RxPG News : Stem Cell Research

Researchers construct erectile tissue in rabbits

Mon, 23 Nov 2009 17:25:07 PST

( from http://www.rxpgnews.com ) The day is not far off when surgeons will be able to reconstruct or replace damaged or diseased penile tissue in humans and enable them to return to a normal life, says a new study.

Researchers at Wake Forest University Baptist Medical Centre's - Institute for Regenerative Medicine - have used tissue engineering techniques to completely replace penile erectile tissue in rabbits.

After implantation, the rabbits had normal sexual function and produced offspring.

Researchers successfully grew erectile tissue from rabbit cells in the lab. This is the most complete replacement of functional penile erectile tissue to date.

The erectile tissue they engineered is known as the corpora cavernosa penis. Two columns of this sponge-like tissue form a significant part of the penis.

These structures, which are bound together with connective tissue and covered with skin, fill with blood during erection.

'Further studies are required, of course, but our results are encouraging and suggest that the technology has considerable potential for patients who need penile reconstruction,' said Anthony Atala, director of IRM.

'Our hope is that patients with congenital abnormalities, penile cancer, traumatic injury and some cases of erectile dysfunction will benefit from this technology in the future.'

Reconstructing damaged or diseased penile erectile tissue has traditionally been a challenge because of the tissue's unique structure and complex function. There is no replacement for this tissue that allows for normal sexual function.

Various surgeries have been attempted, often multi-stage procedures that can involve a silicone penile prosthesis, but natural erectile function is generally not restored.

Wake Forest scientists were the first in the world to engineer a human organ in the lab, bladders that have been implanted in almost 30 children and adults. Many of the same techniques used to build bladders were used in the current study, said a Wake Forest release.

'These results are encouraging,' said Atala. 'They indicate the possibility of using laboratory-engineered tissue in men who require reconstructive procedures. A lack of erectile tissue currently prevents us from restoring sexual function to these patients.'

These findings were published in the online early edition of the Proceedings of the National Academy of Sciences.

Early stage sperm cells created in laboratory

Sat, 14 Apr 2007 06:17:09 PST

( from http://www.rxpgnews.com ) Human bone marrow has been used to create early-stage sperm cells for the first time, a scientific step forward that will help researchers understand more about how sperm cells are created.

For the experiment, Prof Nayernia and his team took bone marrow from male volunteers and isolated the mesenchymal stem cells. These cells have previously been found to grow into other body tissues such as muscle.

They cultured these cells in the laboratory and coaxed them into becoming male reproductive cells, which are scientifically known as âgerm cellsâ.

Genetic markers showed the presence of partly-developed sperm cells called spermatagonial stem cells, which are an early phase of the male germ cell development. In most men, spermatagonial cells eventually develop into mature, functional sperm but this progression was not achieved in this experiment.

The research was carried out in Germany. Prof Nayernia is continuing with this work at NESCI, which has just opened a suite of new laboratories at the Cente for Life in Newcastle.

Earlier research led by Prof Nayernia using mice, published in Laboratory Investigations, also created spermatagonial cells from mouse bone marrow. The cells were transplanted into mouse testes and were observed to undergo early meiosis - cell division - the next stage to them becoming mature sperm cells, although they did not develop further.

Talking about his newly published research paper, Prof Nayernia said : âWeâre very excited about this discovery, particularly as our earlier work in mice suggests that we could develop this work even further.

âOur next goal is to see if we can get the spermatagonial stem cells to progress to mature sperm in the laboratory and this should take around three to five years of experiments. Iâll be collaborating with other NESCI scientists to take this work forward.

Professor Karim Nayernia

Prof Nayernia says a lengthy process of scientific investigation is required within a reasonable ethical and social framework to be able to take this work to its next stage or to say if it has potential applications in terms of fertility treatments in humans.

Prof Nayernia gained worldwide acclaim in July 2006 when he announced in the journal Developmental Cell that he and colleagues had created sperm cells from mouse embryonic stem cells and used these to fertilise mice eggs, resulting in seven live births.

Neural stem cells derived from human embryonic stem cells carry abnormal gene expression

Sun, 06 Aug 2006 06:46:37 PST

( from http://www.rxpgnews.com ) Neural stem cells grown from one of the federally approved human embryonic stem cell lines proved to be inferior to neural stem cells derived from fetal tissue donated for research, a UCLA study has found.

Researchers from the Institute for Stem Cell Biology and Medicine at UCLA coaxed cells from the federally approved line to differentiate into neural stem cells, a process that might one day be used to grow replacement cells to treat such debilitating diseases as Parkinson's and Alzheimer's. However, the neural stem cells expressed a lower level of a metabolic gene called CPT 1A, a condition that causes hypoglycemia in humans.

The study may shed new light on better ways to grow neural and other stem cells in the lab so they mirror normal cells and promote normal functioning, said Guoping Fan, an assistant professor of human genetics and a researcher in UCLA's stem cell institute. The study appears this week in an early online edition of the journal Human Molecular Genetics.

"This study is a very important first step in looking at the differentiation process in neural stem cells," said Fan, senior author of the study. "Now we have a direct measurement of the types of cells that eventually, we hope, will be used for transplantation. We can tell, are they normal or not. Understanding why these cells under-expressed CPT 1A is the first step in a comprehensive understanding of cells obtained from human embryonic stem cells."

The study, Fan said, deals with one of the most important aspects in stem cell biology - potential abnormalities in cells derived from human embryonic stem cells. Stem cells with abnormalities may not effectively treat the diseases they were created to treat, or they may result in secondary problems such as hypoglycemia, Fan said.

UCLA researchers also compared the neural stem cells they grew to cancer cells to ensure that the neural stem cells did not have any abnormalities in a DNA modification associated with gene silencing. The abnormal DNA modification is characteristically a hallmark of cancer cells. The good news, Fan said, is that the neural stem cells in their study did not share any abnormal characteristics associated with cancer. The means, theoretically, that a patient undergoing transplantation with these neural stem cells would not later develop a malignancy.

In the three-year study, researchers compared the neural stem cells grown in the lab from human embryonic stem cells to neural stem cells that already had differentiated and were derived from donated fetal tissue. The question: would the cell lines be the same and mirror the normal neural stem cells found in humans or would one cell line be superior to the other?

"Compared to the normal cells derived from the fetal tissue, the level of gene expression in the neural stem cells grown in the lab is lower," Fan said. "Proper levels of gene expression are essential for normal cell function. This study suggests that the differentiation procedure used in the lab needs to be improved so all genes are properly regulated in the stem cells we grow."

Fan and his colleagues now are studying what may have gone awry in the process they used to coax the human embryonic stem cells to differentiate into neural stem cells that may have resulted in the under-expression of the CPT 1A gene. They're also planning to repeat their work on other federally approved stem cell lines to see if the abnormality was an aberration found only in this one stem cell line. Fan and other UCLA researchers said the abnormality found in the federally approved stem cell line reinforces the need for other embryonic stem cells lines on which to conduct research.

To compare the neural stem cells, researchers extracted DNA fragments and used high throughput micro array technology to study the pattern of DNA cytosine methylation. They also monitored for levels of gene expression that are necessary for cell function as well as abnormalities that might be problematic.

"Any stem cells that might one day be used for transplantation have to be as close as possible to normal stem cells," Fan said. "The next step is to see if we can improve the way we grown these cells. I think we learned an important lesson with this study."

Neurons grown from embryonic stem cells restore function in paralyzed rats

Wed, 21 Jun 2006 00:44:37 PST

( from http://www.rxpgnews.com ) For the first time, researchers have enticed transplants of embryonic stem cell-derived motor neurons in the spinal cord to connect with muscles and partially restore function in paralyzed animals. The study suggests that similar techniques may be useful for treating such disorders as spinal cord injury, transverse myelitis, amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy. The study was funded in part by the NIH's National Institute of Neurological Disorders and Stroke (NINDS).

The researchers, led by Douglas Kerr, M.D., Ph.D., of The Johns Hopkins University School of Medicine, used a combination of transplanted motor neurons, chemicals capable of overcoming signals that inhibit axon growth, and a nerve growth factor to attract axons to muscles. The report is published in the July 2006 issue of Annals of Neurology.

"This work is a remarkable advance that can help us understand how stem cells might be used to treat injuries and disease and begin to fulfill their great promise. The successful demonstration of functional restoration is proof of the principle and an important step forward. We must remember, however, that we still have a great distance to go," says Elias A. Zerhouni, Director of the National Institutes of Health.

"This study provides a 'recipe' for using stem cells to reconnect the nervous system," says Dr. Kerr. "It raises the notion that we can eventually achieve this in humans, although we have a long way to go."

In the study, Dr. Kerr and his colleagues cultured embryonic stem cells from mice with chemicals that caused them to differentiate into motor neurons. Just before transplantation, they added three nerve growth factors to the culture medium. Most of the cells were also cultured with a substance called dibutyrl cAMP (dbcAMP) that helps to overcome axon-inhibiting signals from myelin, the substance that insulates nerve fibers in the spinal cord.

The cells were transplanted into eight groups of paralyzed rats. Each group received a different combination of treatments. Some groups received injections of a drug called rolipram under the skin before and after the transplants. Rolipram, a drug approved to treat depression, helps to counteract axon-inhibiting signals from myelin. Some animals also received transplants of neural stem cells that secreted the nerve growth factor GDNF into the sciatic nerve (the sciatic nerve extends from the spine down the back of the hind leg). GDNF causes axons to grow toward it.

Three months after the transplants, the investigators examined the rats for signs that the stem cell-derived neurons had survived and integrated with the nervous system. The rats that had received the full cocktail of treatments transplanted motor neurons, rolipram, dbcAMP, and GDNF-secreting neural stem cells in the sciatic nerve had several hundred transplant-derived axons extending into the peripheral nervous system, more than in any other group. The axons in these animals reached all the way to the gastrocnemius muscle in the lower leg and formed functional connections, called synapses, with the muscle. The rats showed an increase in the number of functioning motor neurons and an approximately 50 percent improvement in hind limb grip strength by 4 months after transplantation. In contrast, none of the rats given other combinations of treatments recovered lost function.

"We found that we needed a combination of all of the treatments in order to restore function," Dr. Kerr says.

Follow-up experiments with GDNF treatment on only one side of the body showed that, by 6 months after treatment, 75 percent of rats given the full combination of treatments regained the ability to bear weight on the GDNF-treated limbs and to take steps and push away with the foot on that side of the body.

"This research represents significant progress," says David Owens, Ph.D., the NINDS program director for the grant that funded the work. "It is a convergence of embryonic stem cell research with other areas of research that we've funded, including work that uses combination therapies such as rolipram and dbcAMP, growth factors, and cells to facilitate the repair of the injured spinal cord."

Previous studies have shown that stem cells can halt spinal motor neuron degeneration and restore function in animals with spinal cord injury or ALS. However, this study is the first to show that transplanted neurons can form functional connections with the adult mammalian nervous system, the researchers say. They used both electrophysiological and behavioral studies to verify that the recovery was due to connections between the peripheral nervous system and the transplanted neurons.

"We've previously shown that stem cells can protect at-risk neurons, but in ongoing neurodegenerative diseases, there is a very small window of time to do so. After that, there is nothing left to protect," says Dr. Kerr. "To overcome the loss of function, we need to actually replace lost neurons."

While these results are promising, much work remains before a similar strategy could be tried in humans, Dr. Kerr says. The therapy must first be tested in larger animals to determine if the nerves can reconnect over longer distances and to make sure the treatments are safe. There currently is no large-animal model for motor neuron degeneration, so Dr. Kerr's group is working to develop a pig model. Researchers also need to test human embryonic stem cells to learn if they will work in the same way as the mouse cells. It has only recently become possible to grow motor neurons from human embryonic stem cells, Dr. Kerr adds. However, if the future studies go well, this type of therapy might eventually be useful for spinal muscular atrophy, ALS, and other motor neuron diseases.

New stem-cell findings can help the body to cure itself

Fri, 16 Jun 2006 00:48:37 PST

( from http://www.rxpgnews.com ) Researchers at Karolinska Institutet have identified an important mechanism that regulates how many new cells are produced by each intestinal stem cell. The study is published in the latest issue of the prestigious scientific journal, Cell. "This might eventually help us develop new drugs for things like neurological disorders and anaemia," says Professor Jonas Frisén.

In most organs of the body, old cells are continually being replaced by new. If too many new cells are produced, however, it can lead to overgrowth and tumour formation. Too few cells, on the other hand, can result in organ degeneration. It is therefore crucial that exactly the right number of cells are produced.

As many serious disorders cause a reduction in the production of new cells, scientists are keen to develop drugs that stimulate the process, which in turn could help the body to cure itself.

It has long been known that the new cells are often formed by immature cells known as stem cells, but the mechanism regulating the number of new cells produced has remained something of a mystery. However, in a new study to be published by Cell stem-cell researcher Jonas Frisén has succeeded in showing how the body's own stem cells do just this. Working alongside an American group of researchers, Professor Frisén and his team have identified a signal transduction process that regulates the degree of stem-cell division.

"Understanding how cell production is regulated increases our chances of producing drugs able to stimulate the endogenous production of new cells," says Professor Frisén.

He hopes that the new findings can be used to develop drugs that stimulate, for example, the formation of new nerve cells to treat conditions such as stroke and Parkinson's and skin cells to facilitate the healing of wounds. Professor Frisén is best known for his research on cerebral stem cells; the present study, however, has been carried out on stem cells in the intestine, one of the organs in the body with the highest rates of cell renewal.

"We also know that blood, brain and skin stem cells express the genes that we now know to be important in the intestine," he says. "This suggests that the cell production mechanism can be the same for these stem cells too."

The next step for Professor Frisén and his group is therefore to study how blood and skin stem cells go about producing new cells.

Putting avian transgenics on a par with transgenic mice

Thu, 08 Jun 2006 07:42:37 PST

( from http://www.rxpgnews.com ) Origen Therapeutics announced today that it has succeeded in developing a robust and versatile technology for genetically modifying chickens that, for the first time, puts avian transgenics on a par with transgenic mice. The company made the announcement in conjunction with the publication of an article this week by Origen scientists and a collaborator from the University of California, Davis on its transgenic technology in the journal Nature. Using the new technology, Origen can, in principle, make any genetic modification desired to the chicken genome, including the insertion of genetic elements for the production of human therapeutics and the modification of the chicken immune system to produce novel human sequence polyclonal antibodies. Moreover, the new technology opens up the possibility of producing chickens with enhanced agronomic traits, including resistance to avian flu.

"This research breakthrough came when we turned our attention to primordial germ cells, the precursor cells to sperm and eggs," said Marie-Cecile van de Lavoir, senior scientist at Origen. "These cells which we are the first to successfully culture without changing their commitment -- proved to be the key to introducing genetic elements into the chicken genome. As a result, we can now take transgene designs that work well in model systems and breed flocks of birds depositing therapeutic proteins in their eggs. The use of primordial germ cells, the ease of producing small or large flocks of chickens, and the existing infrastructure for rearing chickens and processing eggs means that therapeutic proteins can now be produced efficiently and economically in the eggs of chickens."

Origen scientists first demonstrated the potential for the production of human protein therapeutics in chicken eggs in August 2005, when company scientists published in Nature Biotechnology the production of human sequence monoclonal antibodies having greatly enhanced cancer killing activity compared to antibodies produced via conventional methods.

"While that earlier research was done with chimeric chickens, it demonstrated the enormous opportunities that transgenic chickens hold as a therapeutics production system," said Robert Kay, Ph.D. Origen Therapeutics president and chief executive officer. "We believe a transgenic chicken system offers a number of advantages over either plant or other transgenic animal systems for protein production. Besides the ability to produce antibodies with enhanced cell killing properties, the time from antibody identification to production in eggs is a matter of months, the purification of proteins from eggs is relatively simple, and good manufacturing practices have long been established for vaccine production in chicken eggs. Moreover, the overall cost of facility and operations is a fraction of that associated with fermentation methods of manufacture. The ability to readily create transgenic chickens through this technology, and then to scale up production through conventional breeding further adds to the practicality of this technology for large-scale production of therapeutic proteins."

In the early embryo, only a few cells known as primordial germ cells (PGCs) become sperm or eggs in the adult animal. Previous attempts to culture PGCs from mice and humans produced embryonic germ cells that look and act like embryonic stem cells. The chicken is the first species from which PGCs can be isolated, cultured and genetically modified while retaining their commitment to the germ line. Additionally, under certain conditions, Origen scientists could induce the PGCs in vitro to differentiate into embryonic germ cells that contribute to somatic tissue.

"As well as the practical applications of this work, the ability to engineer PGCs and influence them to commit in cell culture to either the germline or the somatic lineages provides a very useful new tool for understanding some of the earliest and most fundamental events in developmental biology on a molecular level," said Robert J. Etches, Ph.D., D.Sc., vice president of research at Origen Therapeutics.

"This work addresses a major biomedical issue -- how to produce antibody-based medicines in an easy, cost-effective way," said Matthew E. Portnoy, Ph.D., of the National Institute of General Medical Sciences, which partially funded the research. "Beyond that, it will help researchers understand stem cell biology and development --something that holds great value for all sorts of basic studies. This is exactly the kind of result we hope for through our Small Business Innovation Research Program."

Harvard to Create Human Embryonic Stem Cell Lines

Wed, 07 Jun 2006 19:56:37 PST

( from http://www.rxpgnews.com ) After more than two years of intensive ethical and scientific review, Harvard Stem Cell Institute (HSCI) researchers at Harvard and Children's Hospital Boston have been cleared to begin experiments using Somatic Cell Nuclear Transfer (SCNT) to create disease-specific stem cell lines in an effort to develop treatments for a wide range of now-incurable conditions afflicting tens of millions of people.

The work is being entirely supported with private funds because of the federal restrictions on human embryonic stem cell work. If successful, it will mark a major step forward in the effort to use stem cells to treat chronic diseases.

Harvard University Provost Steven E. Hyman said during a June 6 telephone press conference that the work has been the subject of "more than two years of thoughtful, intensive review by as many as eight different Institutional Review Boards and Stem Cell oversight committees at five different institutions," including Harvard, Children's Hospital, Partners Health Care, Brigham and Women's Hospital, Boston IVF, and Columbia University.

Harvard University President Lawrence H. Summers called the approvals "a seminal event in the University's effort to advance this tremendously promising area of science and fulfill that promise as quickly as possible for the countless patients suffering from diabetes, Parkinson's disease, heart disease, cancers, and a host of other illnesses.

"While we understand and respect the sincerely held beliefs of those who oppose this research, we are equally sincere in our belief that the life-and-death medical needs of countless suffering children and adults justifies moving forward with this research," Summers said, referring to the controversy over embryonic stem cell work.

Harvard University Stem Cell Institute researchers (left to right) George Daley, Doug Melton and Kevin Eggan speak to the media about their plan to proceed with SCNT (somatic cell nuclear transfer) in embryonic stem cells. (Credits: Justin Ide/Harvard News Office)

Somatic Cell Nuclear Transfer involves removing nuclei, which contain the cellular DNA (genes) from egg cells, and replacing them with the nuclei of donor cells. The resulting cell is subject to a chemical, or electrical, charge that triggers cell division and the creation of an embryo genetically identical to the donor of the nuclei. In the HSCI experiments, aimed at understanding diseases, the nuclei will be taken from skin cells donated by patients suffering from diabetes, blood diseases, and neurodegenerative diseases.

Research involving human embryonic stem cells is controversial because extracting the cells - which can differentiate into any cell or tissue type in the body - requires the destruction of a human embryo, albeit a blastocyst of only a few hundred cells, literally half the size of the period at the end of this sentence. Melton, in collaboration with Kevin Eggan and Douglas Powers of Boston IVF , has already created 31 stem cell lines using left-over frozen embryos donated by couples who went through in vitro fertilization (IVF), and has distributed those stem cell lines to scientists around the world.

Embryonic stem cells are the master cells of the body, capable of developing into any tissue type. The researchers will seek to learn how to control that differentiation, with a goal of eventually creating lines of cells that can, for instance, produce insulin-making islet cells in the pancreas, which are depleted or absent in diabetics. Melton and Eggan's first nuclear transfer experiments will attempt to create diabetes specific stem cells by removing the nuclei from skin cells taken from diabetic volunteers at the Naomi Berrie Diabetes Center at Columbia University Medical Center and inserting them into donor eggs from which the nuclei have been removed.

In addition to collaborating with Melton on this project, Eggan, whose work is supported by the Stowers Medical Institute, is seeking approvals to study diseases of the nervous system.

Children's Hospital researcher and HSCI Executive Committee member George Daley explains that the ultimate goal of all three HSCI researchers, once they understand how embryonic stem cells are programmed to differentiate into specific cell types, is to literally move a patient's disease into a petri [laboratory] dish. "We plan to take skin cells from a patient with a genetic disease, like sickle cell anemia or any one of more than 40 bone marrow disorders, and reprogram that skin cell back to its embryonic state. We can then study the disease using these cells, correct their genetic defects and coax the repaired cells to become normal blood cells. Our ultimate goal is to return the repaired cells to the patients." Egg donation and reimbursement

Research using human embryonic stem cells is ineligible for federal funding, including grants from the National Institute of Health; only private money may be used to support SCNT research. Under the protocol approved by the Institutional Review Board (IRB) of Harvard's Faculty of Arts and Science, and the IRB of Boston IVF, where the ova will be collected for Melton and Eggan's work, donors will not be paid. The committees struggled to ensure not only that potential donors would understand all potential risks associated with ova donation, but would also understand that they will be contributing to basic science experiments, and that it will be many years - at best - before patients benefit directly from the work.

Speaking of the IRB decisions at Harvard, Children's Hospital, Boston IVF, Brigham and Women's Hospital - where Daley is obtaining ova for his experiments - and Columbia University allowing the Harvard Stem Cell Institute SCNT work to proceed, Melton says, "I think Harvard University has done the right thing by giving this research very careful review by multiple boards, and allowing plenty of time for reconsideration and reflection.

Stem Cell Study for Patients with Heart Attack Damage Seeks to Regenerate Heart Muscle

Sat, 22 Apr 2006 19:15:37 PST

( from http://www.rxpgnews.com ) Rush cardiologists are hoping that transplanted stem cells can regenerate damaged heart muscle in those who experience a first heart attack. The study involves an intravenous infusion of adult mesenchymal stem cells from healthy donor bone marrow that might possibly reverse damage to heart tissue.

A unique benefit of the stem cell product is that it is given to patients through a standard IV line. Other therapies require delivery to the site of the disease through catheterization or open surgical procedures, but this one is very simple and easy for the patient.

A person who has had a single, severe heart attack may survive but can be left with substantial damage to the heart muscle as a result of the blood supply to the heart muscle being cut off during the heart attack. The damaged muscle inhibits the hearts overall ability to pump blood, leading to heart failure, said Rush principal investigator cardiologist Dr. Gary Schaer, head of the Rush Cardiac Catheterization Laboratory. Rush is the only center in Illinois participating in the trial. There are 15 other sites nationwide participating in the study.

He explained that mesenchymal stem cells (MSC) are found in the adult bone marrow and have the potential to develop into mature heart cells and new blood vessels. The MSC cells are derived from normal, healthy adult volunteer bone marrow donors and are not derived from a fetus, embryo or animal. Because they are in an early stage of development, it is believed that they do not trigger an immune response when placed in someone elses body.

Similar to Blood Type O, these MSCs are being used without tissue type matching to a specific patient.

Dr. Schaer says the cells are grown in culture to very high numbers, allowing a single donor's cells to treat thousands of patients. The cells have the ability to expand, or multiply, under controlled conditions, and the expanded cells have the ability to develop into different types of cells in the appropriate environment. One donation can produce billions of MSCs. The cells can be stored for years in a frozen state, ready to be used when they are needed.

Adult stem cells are designed by nature to perform tissue repair in a mature adult. It is believed that these cells can be used in patients unrelated to the donor, without rejection, eliminating the need for donor matching and recipient immune suppression. Once transplanted, the cells promote healing of damaged or diseased tissues.

Research has demonstrated that mesenchymal stem cells follow inflammatory signals or home to sites of injury in the body. Schaer says the stem cells know to go to the heart muscle in a patient who has had a recent heart attack.

When MSCs were injected into animals that have not experienced a heart attack, the cells return to the bone marrow where they were originally located. In animals that had a heart attack induced, the MSCs given intravenously followed the signals to the injured section of the heart and aided in repair. These cells have also been studied for different diseases and have been shown to follow inflammatory signals to various areas of the body to aid in repair. The delivered cells are expected to respond to the body's own signals and migrate to the area of injury.

The Phase I study is double blind; two thirds of the participants receive the stem cells and one-third receive a placebo. To be eligible for the trial, patients must have experienced a first heart attack within the past seven days, and are between 21 and 85 years old. Patients are given a pulmonary breathing test, a CT scan and an MRI before the procedure. Patients undergo an MRI at the end of the study to see how much of the diseased heart muscle has been repaired and measure heart function. A patient may stay in the hospital only 2-3 days for observation, and then go home.

Stem cells - An alternative to skin grafting?

Fri, 07 Apr 2006 13:45:37 PST

( from http://www.rxpgnews.com ) A Singapore company has used stem cells to help victims of serious burns and other wounds grow fresh skin, its chief medical officer said in a report published Friday.

While some more research work has to be done to test the new treatment, Dr Ivor Lim of the Singapore-based Cell Research Corporation said, "the procedure has allowed three patients so far to do away with painful skin grafts".

The company led the research work at the National Hospital of Traditional Medicine and St Paul's Hospital Burns Centre in Vietnam.

The treatment involves growing stem cells on synthetic scaffolds and transferring them onto the patients' wounds. Stem cells are cells that have the ability to continuously divide and develop into various other kinds of cell or tissues.

In case of stem cell treatment "the healing rate has been as fast as with a conventional skin graft, with no complications or rejection", Lim told The Straits Times.

"It would also be a help for patients who are so badly wounded they do not have enough skin for a graft," he added.

Wound healing is widely regarded as an area, which will reap the rewards of stem cell research early.

Bone morphogenetic protein 6 (BMP-6) factor stimulates cartilage growth from stem cells

Wed, 05 Apr 2006 14:41:37 PST

( from http://www.rxpgnews.com ) A novel growth factor significantly improves the ability of specialized stem cells derived from human fat to be transformed into cartilage cells, according to Duke University Medical Center and Pratt School of Engineering researchers.

Such growth factors are crucial to the bioengineering of tissues for clinical use in humans, the researchers said, because cells would need to be grown quickly and in large numbers in order to be practical. For the current study, as well as for past experiments in this area, the Duke team isolated the specialized cells, known as human adipose-derived adult stem cells (hADAS), from fat obtained during liposuction procedures, and then exposed the cells to a cocktail of various growth factors in order to stimulate their transformation into cartilage cells.

The growth factor that the Duke team used in hADAS cells for the first time is called bone morphogenetic protein 6 (BMP-6), a naturally occurring protein that is involved in hardening, or ossifying, the soft ends of long bones that come into contact with cartilage.

The researchers found that BMP-6 significantly increased the production of two important biochemical markers of cartilage cell proliferation. Specifically, hADAS cells treated with BMP-6 increased by 205 times the expression of aggrecan, a component of articular cartilage, and they increased by 38 times the production of a type of collagen uniquely present in cartilage, compared with cells without BMP-6 in the cocktail.

"Our studies suggest that growing hADAS cells with BMP-6 could provide tissue that could be used to repair damaged cartilage," said Bradley Estes, a graduate student in Pratt's Department of Bioengineering and lead author of a paper published in the April 2006 issue of the journal Arthritis and Rheumatism. The team's research was supported by the National Institutes of Health.

"One potential approach would be to take cells from a patient and then treat and grow the cells outside the body to create a tissue that could be reimplanted into the joint," Estes said. "Another strategy would be to use genetic engineering techniques to insert the gene for the production of BMP-6 into hADAS cells and then inject these cells into the site of damage."

Cartilage damage is difficult to treat, the researchers said, because the tissue lacks a supply of blood, nerve and lymph and has limited capacity for repair. Current strategies for treating cartilage damage, such as microfracture surgery or cartilage transplants, have been largely disappointing, they said.

However, over the past five years, Duke researchers under the direction of Farshid Guilak, Ph.D., director of orthopedic research, have been investigating novel approaches to treating cartilage damage. In their experimental system, the team exposes hADAS cells to different cocktails of nutrients, vitamins and growth factors. This chemical reprogramming forces the stem cells to progress along different paths, whether to bone, cartilage or nerve cells.

In their latest experiments, the researchers added BMP-6 to the cocktail in which hADAS cells were grown in tiny spheres of a complex carbohydrate known as alginate. The three-dimensional scaffold provided by the alginate spheres promotes differentiation of treated hADAS cells into cartilage tissue.

Interestingly, the Duke team also found that hADAS cells comprise a distinct lineage of stem cells.

Other researchers have found that a certain type of stem cell, called mesenchymal stem cells, which come from bone marrow, also can be transformed into cartilage cells when exposed to the right cocktail of growth factors. But that is where their similarity with hADAS cells ends, according to the Duke team.

"While the treatment of mesenchymal stem cells with BMP-6 tends to stimulate the transformation into bone cells, the treatment of hADAS cells with BMP-6 stimulates cartilage cell growth, as well as the blockage of bone cell growth," Estes said. "This shows that the hADAS cells we use are very different from the mesenchymal stem cells. They may look alike, but they act quite differently."

Based on their current tests, the researchers are confident that hADAS cells already have demonstrated the potential to serve as a readily available source for creating new cells and tissues to treat cartilage damage. Moreover, the researchers said, evidence suggests that the addition of other growth factors and in differing combinations could generate an even more robust response in the cells that would increase their utility even more.

"We don't currently have a satisfactory remedy for people who suffer a cartilage-damaging injury," Guilak said. "There is a real need for a new approach to treating these injuries. We envision being able to remove a little bit of fat and then grow customized, three-dimensional pieces of cartilage that could be surgically implanted in the joint. One of the beauties of this system is that since the cells are from the same patients, there are no worries of adverse immune responses or disease transmission."

Doctors grow organ from patients' own cells

Wed, 05 Apr 2006 14:15:37 PST

( from http://www.rxpgnews.com ) For the first time in medical history, scientists have grown a human organ from patients' own cells to transplant back into their bodies.

The breakthrough was pioneered by US doctors who developed bladders in the laboratory and are now using their techniques to work on doing the same for 20 kinds of tissues and organs, including blood vessels and hearts.

With tissues grown from their own cells, patients do not face the risk of rejection as they do with ordinary transplants and would not have to live with the fear that a donor might not be found.

"This is one small step in our ability to go forward in replacing damaged tissues and organs," Dr Anthony Atala, who led the research, said Monday in announcing the development.

Atala developed the procedure for patients born with spina bifida, a birth defect in which their spines were not enclosed and that impaired their bladder functions.

The traditional treatment replaces the bladder with one formed from part of the intestine, but because the intestine absorbs nutrients and the bladder excretes, the procedure can lead to its own host of problems, including kidney stones, osteoporosis and a higher cancer risk.

Atala began work in 1990 on an alternative that led to the transplants in seven patients, aged between four and 19 years, which he reported in the Lancet medical journal.

He began his work at Boston Children's Hospital before moving to the Wake Forest University School of Medicine in the US state of North Carolina. Atala said that he and his team of researchers removed a small portion of the patients' bladders, extracted cells from the biopsies and began using those cells to grow more like them in Petri dishes. The cells were then placed on a mold shaped like a bladder to grow further.

In seven to eight weeks after the biopsy, the engineered bladders were then sewn onto the patients' original bladders, and a few weeks after the surgery, the engineered organs had grown into normal-sized bladders and had begun functioning, the researchers said.

The first transplant was done in 1999, and the team said the engineered bladders have functioned as well as bladders reconstructed with intestinal tissue, but without the side effects.

The procedure relieved pressure within the bladder, which can cause kidney damage, and improved the patients' incontinence, they said.

"We have shown that regenerative-medicine techniques can be used to generate functional bladders that are durable," Atala said. "This suggests that regenerative medicine may one day be a solution to the shortage of donor organs in this country for those needing transplants."

Atala added that further study is needed before the techniques could be put into wide use, but additional clinical trials were scheduled to begin this year.

Stem cells can repair torn tendons or ligaments

Wed, 05 Apr 2006 13:34:37 PST

( from http://www.rxpgnews.com ) Weekend athletes who overexert themselves running or playing basketball may one day reap the benefits of research at the Hebrew University of Jerusalem that shows that adult stem cells can be used to make new tendon or ligament tissue.

Tendon and ligament injuries present a major clinical challenge to orthopedic medicine. In the United States, at least 200,000 patients undergo tendon or ligament repair each year. Moreover, the intervertebral disc, which is composed in part of tendon-like tissue, tends to degenerate with age, leading to the very common phenomenon of low-back pain affecting a major part of the population.

Until the present time, therapeutic options used to repair torn ligaments and tendons have consisted of tissue grafting and synthetic prostheses, but as yet, none of these alternatives has provided a successful long-term solution.

A novel approach for tendon regeneration is reported in the April issue of the Journal of Clinical Investigation. Researchers Prof. Dan Gazit and colleagues at the Skeletal Biotechnology Laboratory at the Hebrew University Faculty of Dental Medicine engineered mesenchymal stem cells (MSCs), which reside in the bone marrow and fat tissues, to express a protein called Smad8 and another called BMP2.

When the researchers implanted these cells into torn Achilles tendons of rats they found that the cells not only survived the implantation process, but also were recruited to the site of the injury and were able to repair the tendon. The cells changed their appearance to look more like tendon cells (tenocytes), and significantly increased production of collagen, a protein critical for creating strong yet flexible tendons and ligaments.

Tendon tissue repair was detected using a special type of imaging known as proton DQF MRI, developed by Prof. Gil Navon at Tel Aviv University, which recognizes differences among collagen-containing tissue such as tendon, bone, skin, and muscle. The authors note that BMP and Smad proteins are involved in other tissues such as nerve and liver, suggesting that this type of delivery technology may be helpful for other degenerative diseases.

In an accompanying commentary in the Journal of Clinical Investigation, Dwight A. Towler and Richard Gelberman from the Washington University School of Medicine in St. Louis, Missouri, state, "Given our limited understanding of how MSCs become tenocytes, the recent progress demonstrated in these studies is quite remarkable and may be potentially useful in cell-based therapeutic approaches to musculoskeletal injuries."

New research could coax bone cells into produce up to 75 times more calcium

Tue, 14 Feb 2006 17:12:37 PST

( from http://www.rxpgnews.com ) In a significant advance for regenerative medicine, researchers at Rice University have discovered a new way to culture adult stem cells from bone marrow such that the cells themselves produce a growth matrix that is rich in important biochemical growth factors.

The research, which appears online this week in the Proceedings of the National Academy of Sciences, is notable not just because of the science researchers found they could coax bone cells into produce up to 75 times more calcium but also because the study was conducted by an undergraduate bioengineering senior, Néha Datta.

"These results are important, not just because they hold great promise for regenerating healthy bone but also because they may be applicable to other tissues," said researcher Antonios Mikos, the John W. Cox Professor of Bioengineering and Director of Rice's Center for Excellence in Tissue Engineering. "This is also a notable personal achievement for Néha, because PNAS is one of the top scientific journals in the country and because this is the third peer-reviewed paper and the second first-authored paper -- that she's produced in the past year."

Tissue engineering, also known as regenerative medicine, involves harvesting stem cells from a patient's body and using them to grow new tissues that can be transplanted back into the patient without risk of rejection. Most tissue engineering approaches involve three components: the harvested adult stem cells, growth factors that cause the stem cells to differentiate into the right kind of tissue cells like skin or bone and a porous scaffold, or template, that allows the tissue to grow into the correct shape.

"Finding the right combination of growth factors is always a challenge," Mikos said. "It's not unusual for adult stem cells to progress through a half-dozen or more stages of differentiation on their way to becoming the right tissue and any missed cue will derail the process. In most cases, engineers have little choice but to take a trial-and-error approach to designing a growth-factor regime."

In the study, Mikos's team hit upon the idea of having the stem cells create the proper growth medium themselves. The group, which included graduate student Quynh Pham and postdoctoral research associate Upma Sharma, accomplished this by seeding discs of titanium mesh with stem cells and encouraging them to form extracellular matrix, or ECM, the boney, calcified deposit that gives bone its structural strength.

A comparison was then run on these pre-generated ECM constructs and on non-treated titanium scaffolds. The pre-treated surfaces encouraged calcification at a much faster rate. The researchers also found up to 75 times more calcium in the bone created by tissues in the pre-treated cultures.

"To me, the most important element of the research is that it may one day contribute to new treatment options for patients," said Datta, who is planning to enter medical school in the fall. "One of the reasons I want to become a surgeon is so I can help bring cutting-edge work from the laboratory into clinical practice."

Datta said one of the main reasons she chose to attend Rice was because of the tremendous opportunities available through Rice's Century Scholars Program. The program included funding for tuition as well as a chance to begin research in Mikos's lab during her freshman year.

"My research experience at Rice has been life-changing in ways I could never have imagined four years ago," Datta said. "I never anticipated I would be traveling to international conferences, for example, but from the very beginning Dr. Mikos treated me as a valuable member of his research team. He provided encouragement. He let me follow my ideas. In short, he is the perfect mentor."

Stem cell injections may prove beneficial in treating peripheral artery disease

Fri, 10 Feb 2006 15:59:37 PST

( from http://www.rxpgnews.com ) Indiana University School of Medicine scientists have begun a unique clinical trial using stem cell injections as a treatment that could offer hope to tens of thousands of people who face sores, ulcers and even amputations due to severe peripheral artery disease.

An estimated 10 million Americans are affected by the poor blood circulation -- generally in the legs -- of peripheral artery disease (PAD). It is caused by atherosclerosis, the clogging and hardening of arteries that can lead to heart attacks. Although about half of those with PAD have no symptoms, others report varying levels of pain and other symptoms including numbness and sores on the legs and feet.

Early treatment is similar to actions to prevent heart disease, such as a better diet, stopping smoking cessation, weight loss and if appropriate, cholesterol-lowering drugs. If the disease progresses, patients may receive an artery bypass graft or an angioplasty procedure that widens the blood vessel.

But as many as 12 percent of PAD patients cannot undergo such surgical procedures, and 30,000 to 50,000 people in the United States receive amputations annually due to PAD, said Michael Murphy, M.D. assistant professor of surgery and an investigator at the Indiana Center for Vascular Biology and Medicine at the medical school, who is leading the stem cell trial. For many of these severely affected patients, their quality of life is similar to patients battling terminal cancer, he said.

The cells used in the IU trial include adult stem cells, which are "parent" cells that can create new specialized cells when needed by the body. In the IU trial, researchers are using stem cells -- and slightly more specialized descendants called progenitor cells -- that can create the cells that make up the lining of blood vessels.

In the clinical trial at IU School of Medicine, Dr. Murphy and his colleagues extract bone marrow from the patient's hip while the patient is under a general anesthetic. The adult stem cells and progenitor cells are separated from the bone marrow in a laboratory procedure while the patient recovers from the anesthesia. The cells then are injected into the patient's leg.

Patients will receive one injection and then will be evaluated on several occasions for 12 weeks. IU doctors expect to treat 10 patients in the trial, and seven have already undergone the procedure. (Two of the patients were treated at Duke University where Dr. Murphy was previously on faculty.) Although the researchers will be looking at such indicators as blood vessel growth and wound healing, the current trial is a initial, or phase 1, test meant primarily to demonstrate that the procedure is safe.

However, said Dr. Murphy, "We think this is a very promising treatment that could help patients with severe peripheral artery disease for whom there is now no effective therapy."

Previous studies in animals and other laboratory tests have indicated that injections of the stem and progenitor cells into tissues resulted in development of new blood vessels.

In addition, research has shown that people with heart disease, or who are at increased risk of heart disease, tended to have fewer of the blood vessel stem and progenitor cells circulating in their blood.

"Our hypothesis is that people run out of these cells, or they have inadequate supplies -- perhaps because of genetic factors. As a result, they can't repair or replace damaged blood vessel cells, and heart disease ensues," said Keith March, M.D., Ph.D., director of the vascular biology and medicine center and professor of medicine and of cellular and integrative physiology.

The IU scientists hope to counteract the shortage of those critical cells by introducing the stem cells and progenitor cells taken from the patients' bone marrow. In turn, it's hoped, they will promote blood vessel repair and the growth of new blood vessels by stimulating the production of special protein growth factors.

By introducing the stem and progenitor cells taken from the patient's bone marrow, the IU scientists hope that they will be able to jump-start those repair and replacement processes. They expect that would occur when the bone-marrow derived cells stimulate the production of special protein growth factors that would stimulate the development of new blood vessels.

If the current trial shows that the procedure is safe, the next step would be to test the procedure in a larger number of patients next year, Dr. Murphy said. In that test, the cells would be delivered intravenously in hopes that it would have a broader impact on circulation than a local injection. In addition, he and his colleagues hope to conduct trials using cells taken from fat tissue and from umbilical cord blood to avoid the surgery necessary for bone marrow extraction. Research also is underway to determine whether the cells could be modified in ways to encourage them to produce more growth enhancing proteins before they are given to the patients, Dr. Murphy said.

Hyperbaric oxygen treatments mobilize stem cells

Sun, 01 Jan 2006 21:01:37 PST

( from http://www.rxpgnews.com ) According to a study to be published in the American Journal of Physiology-Heart and Circulation Physiology, a typical course of hyperbaric oxygen treatments increases by eight-fold the number of stem cells circulating in a patient's body. Stem cells, also called progenitor cells are crucial to injury repair. The study currently appears on-line and is scheduled for publication in the April 2006 edition of the American Journal.

Stem cells exist in the bone marrow of human beings and animals and are capable of changing their nature to become part of many different organs and tissues. In response to injury, these cells move from the bone marrow to the injured sites, where they differentiate into cells that assist in the healing process. The movement, or mobilization, of stem cells can be triggered by a variety of stimuli including pharmaceutical agents and hyperbaric oxygen treatments. Where as drugs are associated with a host of side effects, hyperbaric oxygen treatments carry a significantly lower risk of such effects.

"This is the safest way clinically to increase stem cell circulation, far safer than any of the pharmaceutical options," said Stephen Thom, MD, Ph.D., Professor of Emergency Medicine at the University of Pennsylvania School of Medicine and lead author of the study. "This study provides information on the fundamental mechanisms for hyperbaric oxygen and offers a new theoretical therapeutic option for mobilizing stem cells."

"We reproduced the observations from humans in animals in order to identify the mechanism for the hyperbaric oxygen effect," added Thom. "We found that hyperbaric oxygen mobilizes stem/progenitor cells because it increases synthesis of a molecule called nitric oxide in the bone marrow. This synthesis is thought to trigger enzymes that mediate stem/progenitor cell release."

Hopefully, future study of hyperbaric oxygen's role in mobilizing stem cells will provide a wide array of treatments for combating injury and disease.

Clinical trial to test stem cell approach for children with brain injury

Fri, 23 Dec 2005 03:06:38 PST

( from http://www.rxpgnews.com ) A unique clinical trial will gauge the safety and potential of treating children suffering traumatic brain injury with stem cells derived from their own bone marrow starting early next year at The University of Texas Medical School at Houston and Memorial Hermann Children's Hospital.

The clinical trial is the first to apply stem cells to treat traumatic brain injury. It does not involve embryonic stem cells.

"There is no reparative treatment for traumatic brain injury," said principal investigator Charles Cox, M.D., The Children's Fund, Inc. Distinguished Professor in Pediatric Surgery and Trauma at the medical school. "All we can do now is try to prevent secondary damage by relieving pressure on the brain caused by the initial injury."

Unlike bone, muscle and other organs, the brain does not repair itself effectively. Traumatic brain injury victims can regain some function through rehabilitation. Studies show between 15 and 25 percent of children suffering severe traumatic brain injury die, and survivors of even moderate injury often are devastated for life.

Approved by the U.S. Food and Drug Administration and the university's Committee for the Protection of Human Subjects (CPHS), the clinical trial builds on laboratory and animal research indicating that bone-marrow derived stem cells can migrate to an injured area of the brain, differentiate into new neurons and support cells, and induce brain repair.

"This would be an absolutely novel treatment, the first ever with potential to repair a traumatically damaged brain," said James Baumgartner, M.D., associate professor of pediatric neurosurgery and co-principal investigator on the project.

As a Phase I clinical trial, the project's first emphasis is to establish the safety of the procedure, with a secondary goal of observing possible therapeutic effects.

Cox and Baumgartner have permission to recruit 10 head injury patients to the study between the ages of 5 and 14 who meet criteria set for enrollment. After initial treatment and evaluation, a pediatric surgeon will approach the injured child's parents to explain the trial and request permission to enroll the child in the study.

If permission is granted, bone marrow will be extracted from the child's hip and then processed to derive two types of progenitor stem cells: mesenchymal stem cells, which differentiate into bone, cartilage and fat cells, and research indicates can also differentiate into neurons; and hematopoietic stem cells, which form all the cells needed for blood.

Preclinical research indicates that the mesenchymal stem cells play the major role in producing new neurons and support cells.

The Center for Cell and Gene Therapy at Baylor College of Medicine will process the bone marrow into the stem cell preparation and return it to Memorial Hermann Children's Hospital, where it will be given intravenously to the injured child.

All of this will be accomplished within 48 hours of the injury, Cox said. The children will be carefully monitored throughout for possible side effects. They will be evaluated for brain function one month and six months after the procedure to see if it is improved compared with historical data on the brain function of children of similar age who suffered a similar injury.

Safety trials involve too few patients to draw broad conclusions about the effectiveness of treatment. But they can set the stage for larger-scale research.

"All the preclinical data suggest this is a safe procedure with substantial information suggesting a possible treatment effect," Cox said.

Because the children are receiving their own cells, an immunological response to the treatment is unlikely.

Even marginal improvement could mean a great deal to someone who suffers a brain injury. "It could be the difference between being able to recognize your loved ones and not being able to, or between doing things for yourself or having to rely on others. That would be a huge impact on families and on society," Cox said.

Trauma is far and away the main cause of death and disability among children, and the main reason children die from trauma is brain injury, Cox said.

The proposal was under review for a year. The U.S. Food and Drug Administration approved Cox's Investigational New Drug (IND) application in September. The UT-Houston CPHS, the university's institutional review board for research projects, approved the project in November and will continue to monitor it.

The project is funded by the Memorial Hermann Foundation, internal research funds from The Office of the President at The University of Texas Health Science Center at Houston, and the National Institute of Child Health and Development and the National Heart, Lung, and Blood Institute of the National Institutes of Health.

How stem cells become brain cells

Thu, 15 Dec 2005 16:11:38 PST

( from http://www.rxpgnews.com ) Researchers at the Oregon National Primate Research Center at Oregon Health & Science University (OHSU) have discovered one key gene that appears to control how stem cells become various kinds of brain cells. The finding has significant implications for the study of Parkinson's disease, brain and spinal cord injury, and other conditions or diseases that might be combated by replacing lost or damaged brain cells.

"In the early stages of brain development prior to birth, brain stem cells, also known as neural stem cells, will differentiate into neurons," explained Larry Sherman, Ph.D., an associate scientist in the Division of Neuroscience at the Oregon National Primate Research Center and an adjunct associate professor of cell and developmental biology in the OHSU School of Medicine. "In later stages, these same stem cells suddenly start becoming glial cells, which perform a number of functions that include supporting the neurons. We wanted to find out what factors cause this switch in differentiation. We also wanted to determine if the process can be controlled and used as a possible therapy. What amazed us is that it turns out a single gene may be responsible for this incredibly important task."

The key gene that the scientists studied is called brahma-related gene-1 (Brg-1) that is found in both mice and humans. This protein had been previously studied extensively in human cancers, but not in the nervous system. To determine the precise role of Brg-1, Sherman, in collaboration with Dr. Steven Matsumoto from the Integrative Biosciences Department at the OHSU School of Dentistry, bred mice lacking the gene in the nervous system. This resulted in the development of embryos with smaller brains containing neurons but virtually no glial cells. When they isolated neural stem cells, placed them into cell culture and then removed Brg1, the cells in the culture turned into neurons but failed to differentiate into glia.

"This research shows us that in mice, Brg-1 is a critical signal that prevents stem cells from turning into neurons at the wrong time. However, since we can manipulate Brg1 expression in stem cells in culture, we now have a powerful way to generate neurons that could be used to replace cells lost in a variety of diseases and conditions that affect the brain and spinal cord. That is our next step." said Sherman. "Since the process only involves a single gene, it is highly amenable for the development of drugs targeted at promoting stem cell differentiation in the adult nervous system."

While much more research needs to be conducted, the scientists believe these findings could play a role in the development of therapies to combat a variety of diseases and conditions. For instance, Parkinson's disease is related to the loss of dopamine-producing brain cells. Scientists hypothesize that it may be possible to correctly time the expression of brg-1 in neuronal stem cells either in a culture dish or in the brain to replace the lost dopamine-producing cells. Another possibility would be the replacement of lost or damaged motor neurons in patients who have suffered brain or spinal cord damage.

This research was funded in part by the Medical Research Foundation of Oregon, the National Institute's of Health and the Christopher Reeve Paralysis Foundation.

"CRF is pleased to have provided support for this study", said Susan Howley, Director of Research and Executive Vice President, Christopher Reeve Foundation. "Identifying a gene that controls how stem cells turn into different kinds of nerve cells has important implications for clinical application in spinal cord repair strategies."

Human Brain Cells Grown Inside Mouse Skull

Tue, 13 Dec 2005 15:28:38 PST

( from http://www.rxpgnews.com ) Previous studies have shown that undifferentiated human embryonic stem cells (hESC) can survive in the brains of laboratory rats with Parkinsons disease. But until now it was unclear whether hESCs can become fully functional members of the host animals neuronal architecture - a basic necessity if stem cells are ever to be used in medical treatments replenishing missing or damaged neurons in human patients with neurodegenerative diseases such as Parkinson's or Alzheimers disease.

Now, research at the Salk Institute for Biological Studies indicates for the first time that hESCs mature into fully functional adult brain cells and integrate into the existing nervous system when these human cells are injected in the developing brains of two-week-old mouse embryos.

The Salk researchers led by Fred H. Gage, Ph.D, professor and co-head of the Laboratory of Genetics at the Salk Institute, published their finding in this weeks Proceedings of the National Academy of Science.

Besides its therapeutic potential, our finding also opens up the possibility to study human disease in a new context, says first author Alysson R. Muotri, Ph.D. We can ask if neurodegeneration is the function of an individual diseased cell or if it is caused by the local environment in the brain.

Far less than 0.1 percent of their brain cells were of human origin, and those few had taken on the size and shape of their neighbors. This illustrate that injecting human stem cells into mouse brains doesnt restructure the brain, explains Gage.

At least in theory, hESCs can grow indefinitely in the lab as unspecialized cells and can be coaxed to differentiate into various cell types.

This assay will be very valuable to determine whether any given human stem cell lines still have the capacity to form fully functional neurons, says Gage, explaining that scientists currently do not know whether stem cells that have been kept in culture outside the body for extended periods of time have lost the potential to become a neuron or not.

He also emphasizes that this procedure will also allow other laboratories and drug companies to test the toxicity of new compounds and assess their effects on human brain cells, not just in a Petri dish, but in the context of a functional brain.

In the past, hESC injected into adult mice often formed tumors or were rejected by the mouse immune system. Hoping to circumvent these problems, Gage and his team opted for injecting hESCs into the developing brains of embryonic mice.

The green glowing hESCs differentiated into different types of neurons and supporting glia cells, migrated throughout the brain and settled in different regions without forming tumors or being rejected by the mouses immune system.

When we characterized these cells two months later, we found that had the morphology, shape and characteristics of mouse cells, says Gage.

Other authors who contributed to the work include co-first author Kinichi Nakashima, formerly at the Salk and now at Nara Institute of Science and Technology in Japan, and post-doctoral researchers Nicolas Toni and Vladislav M. Sandler. In accordance with guidelines and the Salks internal Human Stem Cell Research Guidelines, the mice used in these experiments were not allowed to breed.

Stem cells may trigger bone cancer

Wed, 23 Nov 2005 21:29:38 PST

( from http://www.rxpgnews.com ) Stem cells may cause some forms of bone cancer, University of Florida scientists report.

The researchers are the first to identify a population of cells with characteristics of adult and embryonic stem cells in cultures derived from biopsies of patients' bone tumors. They describe their findings in this month's issue of the medical journal Neoplasia.

"We're saying the cell of origin of these tumors may be very, very primitive," said C. Parker Gibbs, M.D., an associate professor of orthopaedic oncology and a member of the UF Shands Cancer Center. Gibbs collaborated with several UF scientists, including Dennis A. Steindler, Ph.D., director of UF's McKnight Brain Institute.

Researchers elsewhere already have implicated stem cells in the development of leukemia, and Steindler's lab previously discovered stem-like cells in brain cancer. Others have identified these same cells in some breast cancers.

The studies are laying the foundation for novel ideas about cancer and its development, and are opening new avenues of research that could someday lead to more effective treatments that target the mutant cells that grow into tumors.

The cancer stem cell theory holds that a small subpopulation of rogue stem cells exists within a tumor and has the ability to sustain itself. As these abnormal cells divide, they may generate the bulk of a malignant tumor, then help to spur on its growth.

"Most current chemotherapeutic regimens are developed against the bulk tumor and therefore may not affect the small number of malignant stem cells, allowing recurrence and even metastasis," Gibbs said.

Osteosarcoma is the most common bone malignancy in children, most of whom are 10 to 20 years old and in a period of rapid growth when the disease is diagnosed. Despite advances in surgery and chemotherapy, many patients do not survive long-term.

"Osteosarcoma is an extremely aggressive tumor that destroys bone and requires surgery and chemotherapy to cure," Gibbs said. "The current cure rate is approximately 65 percent with yearlong chemotherapy and radical surgery, but we still lose 30 to 40 percent of these kids despite that kind of aggressive therapy. So the thought was, 'Gee, what are we missing?'

"The existence of stem-like cells in bone sarcomas suggests that the study of stem cell biology may provide opportunities for targeted therapies that are markedly less toxic than current aggressive chemotherapy and surgical protocols," he added.

Stem cells are primed to multiply and divide in almost unlimited fashion, and develop into many kinds of organs. A bone stem cell, for example, develops into bone. Osteosarcoma resembles bone but looks abnormal. A stem cell "gone bad" could potentially multiply to produce an abnormal organ that is cancerous, Gibbs said.

"Osteosarcoma occurs right next to the most active centers of growth, the growth plates in long bones," Gibbs said. "These areas of the skeleton contain many stem cells undergoing rapid growth and developing into bone during the adolescent growth spurt. It makes sense that bone sarcomas occur in anatomic areas containing stimulated stem cells. A stimulated, abnormal stem cell might therefore be the cell of origin of osteosarcoma."

UF researchers studied two types of tumors - osteosarcomas common in childhood and adolescence, and chondrosarcomas, a form of adult bone cancer that requires aggressive surgery to treat because it does not respond to chemotherapy or radiation.

Using specialized cell culture techniques, they were able to isolate stem-like cells from bone tumors. About one in 1,000 cells in the samples they studied had features of embryonic stem cells. The researchers also found abundant levels in their samples of the two key factors that help maintain embryonic stem cells in a very primitive state.

"We found expression of these two transcription factors not only in culture but also in actual tumors," Gibbs said. "We were first to show these cancers expressed both of these embryonic stem cell markers.

"That these cells exist in bone sarcomas suggests osteosarcomas and chondrosarcomas might be stem cell diseases," he added. "This is pretty exciting stuff."

The discovery gives scientists new targets for treatment, he said.

"The next step, which is ongoing, is isolating and growing tumors from these cells in animals and then finding ways to interfere with that growth based on their stem cell biology," Gibbs said. "So the study of embryonic and adult stem cell biology may provide more effective ways to treat childhood sarcomas."

Still, the precise role stem-like cells play in the development of cancer is not entirely clear, said Eric C. Holland, M.D., Ph.D., an associate professor in the departments of neurosurgery, neurology, and cancer biology and genetics at Memorial Sloan-Kettering Cancer Center.

"Dr. Gibbs' identification of very early cells in these tumors has important implications for our understanding of cancer biology," Holland said. "But further work needs to be done to determine what the role of cells of this nature is in cancer biology - whether they are the cells of origin, the cause of cancer or the effect of the environment generated by a tumor. Clearly it's quite an exciting time for people who are interested in cells like this."

Stem cells successfully grown into cartilage cells

Wed, 16 Nov 2005 20:56:38 PST

( from http://www.rxpgnews.com ) Scientists from Imperial College London have successfully converted human embryonic stem cells into cartilage cells, offering encouragement that replacement cartilage could one day be grown for transplantation.

Cartilage is the dense connective tissue usually found between bones to allow the smooth movement of joints.

Research to be published in Tissue Engineering shows how the Imperial team directed embryonic stem cells to become cartilage cells. This could allow doctors to grow cartilage for transplantation for a number of injuries and medical problems, including sports injuries, new cartilage for people having hip replacements, and even for cosmetic surgery.

Dr Archana Vats, from Imperial College London and first author of the paper, said: "The ability to grow cartilage using stem cells could have enormous implications for a number of medical problems. With the UK's increasing ageing population there will be an inevitable increase in problems created by people living longer. Although doctors have been able to carry out joint replacements for a number of years, it has not possible to replace the worn out cartilage. By replacing the cartilage it may be possible to avoid the need for a joint replacement for some time."

The research involved growing human embryonic stem cells with chondrocytes or cartilage cells, in Petri dishes in the laboratory in a specialised system that encouraged them to change into cartilage cells. When this was compared with just growing the human embryonic stem cells alone, the mixed stem cells and cartilage were found to have higher levels of collagen, the protein constituent of cartilage.

The cells were then implanted in mice on a bioactive scaffold for 35 days. When they removed the scaffold, the cells were found to have formed new cartilage, showing they can be successfully transplanted in living tissue.

The scientists also believe this technique could be used in cosmetic and reconstructive surgery. When removing head and neck cancers, surgeons often have to cut away parts of cartilage, and then take grafts from other parts of the body. With this new technique doctors would potentially be able to take stem cells from the patient, grow them in a laboratory, and then transplant them after the surgery.

This work builds on an earlier collaboration between medical researchers and engineers at Imperial College. The team had previously developed the bioactive scaffold which was used as a scaffold to grow the stem cells on.

Dr Anne Bishop, from Imperial College London, and one of the authors, added: "The potential of stem cells has been widely known for many years, but it is only recently we have started to make progress towards the ultimate goal of using them in patients. These results show it may be as little as five years before this advance can be used to directly benefit patients for a huge variety of illnesses and injuries."

The team included Professor Dame Julia Polak, Head of the Tissue Engineering and Regenerative Medicine Centre, Imperial College London, as well as Mr Neil Tolley, ENT Dept, St Mary's Hospital and also researchers from the University of Bristol.

Functional ion channels in human embryonic stem cells (ESCs) discovered

Sat, 22 Oct 2005 02:32:38 PST

( from http://www.rxpgnews.com ) Researchers from Johns Hopkins have discovered the presence of functional ion channels in human embryonic stem cells (ESCs). These ion channels act like electrical wires and permit ESCs, versatile cells that possess the unique ability to become all cell types of the body, to conduct and pass along electric currents.

If researchers could selectively block some of these channels in implanted cells, derived from stem cells, they may be able to prevent potential tumor development. The paper appears Aug. 5 online in the journal Stem Cells.

"A major concern for human ESC-based therapies is the potential for engineered grafts to go haywire after transplantation and form tumors, for instance, due to contamination by only a few undifferentiated human ESCs," says Ronald A. Li, Ph.D., an assistant professor of medicine at The Johns Hopkins University School of Medicine and senior author of the study. "Our discovery of functional ion channels, which are valves in a cell's outer membrane allowing the passage of charged atoms, the basis of electricity, provides an important link to the differentiation, or maturation, and cell proliferation, or growth of human ESCs."

Because human ESCs can potentially provide an unlimited supply of even highly specialized cells, such as brain and heart cells, for transplantation and cell-based therapies, they may provide an ultimate solution to limited donor availability.

In an earlier study, Li's lab genetically engineered heart cells derived from human ESCs, suggesting the possibility of transplanting unlimited supplies of healthy, specialized cells into damaged organs.

"We do not want to be taking any chances of tumor formation. Based on our previous research, we therefore decided to explore the existence of ion channels in pluripotent, or versatile, human ESCs because electrical activity is known to regulate cell differentiation and proliferation," says Li. "To my knowledge, the electrical properties of human ESCs were never studied up to this point."

In the current study, the researchers measured the electric currents of single human ESCs, discovered several channels that allow and control passage of potassium, and observed the electric current's effect on cell differentiation and proliferation.

"In a number of different cell types, from cancer to T-lymphocytes, potassium channels are responsible for altering the membrane voltage of cells," says Li. "This in turn is required for the progression of certain cells into the next phase of a cell cycle."

Li hopes the targeting of specific potassium channels will give scientists more understanding and control in engineering healthy cells for transplantation.

"We found that blocking potassium channels in ESCs also slowed their growth," says Li. "Our findings may lead to genetic strategies that suppress undesirable cell division after transplantation, not only for ESCs and their derivatives, but perhaps for adult stem cells as well." Li adds that much more work is necessary to know for sure.

New Approach Maintains Developmental Potential of Embryo

Tue, 18 Oct 2005 13:55:38 PST

( from http://www.rxpgnews.com ) The generation of embryonic stem cell lines using an alternative approach that does not interfere with the developmental potential of embryos is possible. The research, which appears online (ahead of print) in the journal Nature, by ACT and its collaborators, describes a method of deriving stem cells in mice using a technique of single-cell embryo biopsy similar to that used in preimplantation genetic diagnosis (PGD) to test for genetic defects.

The most basic objection to embryonic stem cell research is the fact that embryos are deprived of any further potential to develop into a complete human being, said Robert Lanza, Medical Director at ACT, and senior author of the study. We have shown in a mouse model that you can generate embryonic stem cells using a method that does not interfere with the developmental potential of the embryo. It is important to note that this work was performed in the mouse and needs to be extended to the human species. It would be tragic not to pursue all options and methods available to us to get this technology to the bedside as soon as possible, added Lanza.

Five embryonic stem (ES) cells and seven extraembryonic (trophoblast) stem cell lines were produced from single mouse blastomeres, which maintained normal karyotype (chromosome type) and markers of pluripotency or TS cells for up to more than 50 passages. The ES cells differentiated into derivatives of all three germ layers both in vitro and in chimeric offspring and teratomas. Single-blastomere-biopsied embryos developed to term without a reduction in their developmental capacity. These results are consistent with human data, which indicate that normal and PGD-biopsied embryos develop into blastocysts with comparable efficiency.

In the past, stem cell lines have been isolated from the inner cell mass of blastocysts and in a few instances, from earlier, cleavage-stage embryos said Young Chung, Senior Scientist at ACT, and first author of the paper. We generated five ES and seven trophoblast stem (TS) cell lines from single mouse embryo cells. The stem cells were able to generate all the cell types of body, including nerve cells, bone, and beating heart.

Ultimately the goal of stem cell research is to provide new treatments for what are now incurable diseases, added Michael West, President & Chief Scientific Officer at ACT. Therefore, it is important to emphasize that these advances do not obviate the need of medical researchers to pursue somatic cell nuclear transfer and other related technologies that have so much potential in the emerging field of regenerative medicine.

Spinal cord injury treatment with neural stem cells

Tue, 20 Sep 2005 20:37:38 PST

( from http://www.rxpgnews.com ) Researchers at the UC Irvine Reeve-Irvine Research Center have used adult human neural stem cells to successfully regenerate damaged spinal cord tissue and improve mobility in mice.

The findings point to the promise of using this type of cells for possible therapies to help humans who have spinal cord injuries. Additionally, transplanted cells differentiated into new neurons that formed synaptic connections with mouse neurons.

When myelin is stripped away through disease or injury, sensory and motor deficiencies result and, in some cases, paralysis can occur. Previous Reeve-Irvine research has shown that transplantation of oligodendrocyte precursors derived from human embryonic stem cells restores mobility in rats.

We were excited to find that the cells responded to the damage by making appropriate new cells that could assist in repair. This study supports the possibility that formation of new myelin and new neurons may contribute to recovery.

Mice that received human neural stem cells nine days after spinal cord injury showed improvements in walking ability compared to mice that received either no cells or a control transplant of human fibroblast cells (which cannot differentiate into nervous system cells). Further experiments showed behavioral improvements after either moderate or more severe injuries, with the treated mice being able to step using the hind paws and coordinate stepping between paws whereas control mice were uncoordinated.

The cells survived and improved walking ability for at least four months after transplantation. Sixteen weeks after transplantation, the engrafted human cells were killed using diphtheria toxin (which is only toxic to the human cells, not the mouse). This procedure abolished the improvements in walking, suggesting that the human neural stem cells were the vital catalysts for the maintained mobility.

This study differs from previous work using human embryonic stem cells in spinal cord injury because the human neural stem cells were not coaxed into becoming specific cell types before transplantation.

This work is a promising first step, and supports the need to study multiple stem cell types for the possibility of treating of human neurological injury and disease, Anderson said.

SPECT/CT can trace stem cells destinations after being injected

Wed, 14 Sep 2005 21:37:38 PST

( from http://www.rxpgnews.com ) A team of scientists from the Johns Hopkins Department of Radiology and Institute of Cell Engineering has used a non-invasive imaging technique, called SPECT/CT, to successfully trace stem cells destinations after being injected into the body to treat animal hearts damaged by myocardial infarction, or heart attack.

In the study, researchers surgically induced acute myocardial infarctions in seven dogs, six of which later received canine mesenchymal stem cells (MSCs) labeled with a radioactive tracer and magnetic resonance imaging (MRI) contrast agent to enhance image quality. Both the tracer and contrast agent are widely used in research and routine clinical practice.

The internal distribution of the injected stem cells was tracked with SPECT/CT and MRI scanners immediately after injection as well as at multiple time points over seven days to assess whether the MSCs preferentially migrated or homed in on damaged cardiac tissue. Previous studies in animals were only able to demonstrate homing by examining the tissue microscopically after death.

The teams results, reported in the Sept. 6, 2005, issue of Circulation, revealed redistribution of the radiolabeled MSCs from the initial localization in the lungs to the target organ, the heart, at 24 hours post-injection. Moreover, the cells remained visible in SPECT/CT images until seven days after the injection.

SPECT/CT also found redistribution of the MSCs to non-target organs, such as the liver, kidney and spleen. Measuring the radiation levels in tissues obtained from the animals after their death validated these finding.

MRI, because of its lower sensitivity, was unable to demonstrate targeted cardiac localization of MSCs.

Our study demonstrates that SPECT/CT imaging is well suited to dynamically track the biodistribution and movement of stem cells to both target and non-target organs, says lead investigator Dr. Dara L. Kraitchman, an associate professor of radiology at the Johns Hopkins Russell H. Morgan Department of Radiology and Radiological Science. Such a non-invasive means of studying stem cell movement could be very helpful in monitoring therapeutic safety and efficacy in clinical trials. With her co-workers, Drs. Jeff W.M. Bulte, Mark F. Pittenger, Benjamin M.W. Tsui, Randell G. Young, and Richard L. Wahl, she anticipates that this technique will useful in developing customized therapies for future patient trials.

SPECT, or single photon emission computed tomography, is a special type of emission computed tomography (ECT) scan in which a small amount of a radioactive tracer is injected into a vein, and a scanner is used to make detailed images that are highly sensitive to the location of the radioactive materials inside the body. CT, or computed tomography, uses X-rays to produce high-resolution images of the anatomical structure of the bodys interior. Combining the two techniques greatly enhances anatomical mapping and localization, permitting researchers to know more precisely what cells or organs are taking up the radiolabeled tracer.

A new link between stem cells and tumors

Wed, 14 Sep 2005 03:37:38 PST

( from http://www.rxpgnews.com ) Scientists at the European Molecular Biology Laboratory [EMBL] in Heidelberg and the Institute of Biomedical Research of the Parc Científic de Barcelona [IRB-PCB] have now added key evidence to claims that some types of cancer originate with defects in stem cells. The study, reported this week in the on-line edition of Nature Genetics [September 4] shows that if key molecules aren't placed in the right locations within stem cells before they divide, the result can be deadly tumors.

Cells in the very early embryo are interchangeable and undergo rapid division. Soon, however, they begin differentiating into more specific types, finally becoming specialized cells like neurons, blood, or muscle. As they differentiate, they should stop dividing and usually become embedded in particular tissues. Some tumor cells are more like stem cells because they are identical, they divide quickly, and in the worst case metastasize they wander through the body and implant themselves in new tissues.

Specialized cells may die through age or injuries, so the body keeps stocks of stem cells on hand to generate replacements. Usually the stem cell divides into two types: one that is just like the parent, which is kept to maintain the stock, and another that differentiates. This is what happens with neuroblasts. Cell division creates one large neuroblast and a smaller cell that can become part of a nerve. This process is controlled by events that happen prior to division. The parent cell becomes asymmetrical: it collects a set of special molecules, including Prospero and other proteins, in the area that will bud off and become the specialized cell.

"This asymmetry provides the new cell with molecules it needs to launch new genetic programs that tell it what to become," says Cayetano González, whose group began the project at EMBL and has continued the work as they moved to the IRB-PCB. "The current study investigates what happens when the process of localizing these molecules is disturbed."

Whether Prospero and its partners get to the right place depends on the activity of specific genes in the stem cell. EMBL PhD student Emmanuel Caussinus from González's group created neuroblasts in which these genes were disrupted. "We no longer had normal neuroblasts and daughter cells capable of becoming part of a nerve," Caussinus says. "Instead, we had a tumor."

When these altered cells were transplanted into flies, the results were swift and dramatic. The tissue containing the altered cells grew to 100 times its initial size; cells invaded other tissues, and death followed. The growing tumor became "immortal", Caussinus says; cells could be retransplanted into new hosts for years, generation after generation, with similar effects.

The study proves that specific genes in stem cells those which control the fates of daughter cells are crucial. If such genes are disrupted, the new cells may no longer be able to control their reproduction, and this could lead to cancer. "It puts the focus on the events that create asymmetrical collections of molecules inside stem cells," González says. "This suggests new lines of investigation into the relationship between stem cells and tumors in other model organisms and humans."

Some cancers originate with defects in stem cells

Tue, 06 Sep 2005 06:33:38 PST

( from http://www.rxpgnews.com ) Scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg and the Institute of Biomedical Research of the Parc Científic de Barcelona (IRB-PCB) have now added key evidence to claims that some types of cancer originate with defects in stem cells. The study, reported this week in the on-line edition of Nature Genetics (September 4) shows that if key molecules aren't placed in the right locations within stem cells before they divide, the result can be deadly tumors.

Cells in the very early embryo are interchangeable and undergo rapid division. Soon, however, they begin differentiating into more specific types, finally becoming specialized cells like neurons, blood, or muscle. As they differentiate, they should stop dividing and usually become embedded in particular tissues. Some tumor cells are more like stem cells because they are identical, they divide quickly, and in the worst case metastasize they wander through the body and implant themselves in new tissues.

Specialized cells may die through age or injuries, so the body keeps stocks of stem cells on hand to generate replacements. Usually the stem cell divides into two types: one that is just like the parent, which is kept to maintain the stock, and another that differentiates. This is what happens with neuroblasts. Cell division creates one large neuroblast and a smaller cell that can become part of a nerve. This process is controlled by events that happen prior to division. The parent cell becomes asymmetrical: it collects a set of special molecules, including Prospero and other proteins, in the area that will bud off and become the specialized cell.

"This asymmetry provides the new cell with molecules it needs to launch new genetic programs that tell it what to become," says Cayetano González, whose group began the project at EMBL and has continued the work as they moved to the IRBB-PCB. "The current study investigates what happens when the process of localizing these molecules is disturbed."

Whether Prospero and its partners get to the right place depends on the activity of specific genes in the stem cell. EMBL PhD student Emmanuel Caussinus from González's group created neuroblasts in which these genes were disrupted. "We no longer had normal neuroblasts and daughter cells capable of becoming part of a nerve," Caussinus says. "Instead, we had a tumor."

When these altered cells were transplanted into flies, the results were swift and dramatic. The tissue containing the altered cells grew to 100 times its initial size; cells invaded other tissues, and death followed. The growing tumor became "immortal", Caussinus says; cells could be retransplanted into new hosts for years, generation after generation, with similar effects.

The study proves that specific genes in stem cells those which control the fates of daughter cells are crucial. If such genes are disrupted, the new cells may no longer be able to control their reproduction, and this could lead to cancer. "It puts the focus on the events that create asymmetrical collections of molecules inside stem cells," González says. "This suggests new lines of investigation into the relationship between stem cells and tumors in other model organisms and humans."

Challenging the accepted theory of stem cell operation in kidney repair

Sun, 04 Sep 2005 09:09:38 PST

( from http://www.rxpgnews.com ) Acute renal failure, or ARF, is as serious as it sounds. An estimated 40% of critical care hospital admissions experience ARF. Estimates of their death rate range from 50% to 80%, complicated by the fact that patients with ARF often simultaneously suffer failure of other major organ systems.

The most serious form of ARF is caused by ischemia, or loss of blood supply to the kidneys caused by shock, blood infection or major cardiovascular surgery, particularly in such high- risk patients as those with diabetes, underlying renal disease, and the elderly. In the kidneys, such insults lead to destruction of kidney tubular and vascular cells, initiating a significant inflammatory response. Recovery of kidney function that is adequate for patient survival depends primarily on the protection and regeneration of destroyed and injured cells.

Yet virtually no progress has been made toward development of any highly effective ARF therapy for decades. Basically, catastrophic loss of kidney function has remained treatment-resistant despite dialysis and intensive care. Treating patients with ARF thus presents a major clinical dilemma, particularly when severe ARF occurs with multiple organ failure, Christof Westenfelder from the University of Utah explained. Our laboratory has therefore been pursuing development of novel therapeutic interventions that are urgently needed to treat this common, devastating and costly human disease, Westenfelder said.

Challenging the accepted theory of stem cell operation

In a new study, Westenfelders team reported that injecting stem cells similar to the type used in bone marrow transplants is highly renoprotective, showing almost immediate improvement in both kidney function and degree of tissue injury, followed by accelerated regeneration and return of function, he said. Furthermore, these beneficial effects are predominantly mediated, as our data suggest, by paracrine rather than transdifferentiation-dependent mechanisms, the paper reported. Paracrine indicates action instigated by nearby cells.

These new results challenge the most popular hypothesis of how stem cells work in kidney protection and repair, which holds that administered stem cells enter an injured organ where they differentiate into those cells that have been destroyed, and thus replace them both anatomically and functionally, Westenfelder said.

MSC paracrine effects prompt a positive cascade, halt inflammatory response

Rather, the Utah team found that administered stem cells dont stay in the kidney that has ARF long enough to differentiate into kidney cells, but rather appear to alter the course of ARF by a number of identifiable and some still unexplored paracrine mechanisms. The former include the induction of organ-protective and repair-supporting genes in surviving renal cells, robust suppression of proinflammatory cytokines in the ARF kidney and upregulation of anti-inflammatory genes, as well as the delivery and release at the site of injury of organ-protective and other beneficial gene products by the stem cells per se. Collectively, these and as yet unidentified mechanisms represent a highly potent intervention in ARF, Westenfelder stated.

The study, Administered mesenchymal stem cells protect against ischemic acute renal failure through differentiation-independent mechanisms, appears in the American Journal of Physiology-Renal Physiology, published by the American Physiological Society. Research was conducted by Florian Tögel, Zhuma Hu, Kathleen Weiss, and Christof Westenfelder of the University of Utah and the Veterans Affairs Medical Center; Jorge Isaac, University of Utah; and Claudia Lange, Bone Marrow Transplantation Center, Hamburg.

Stem cell time in the kidney: about two hours

At first, Westenfelder conceded, the researchers experienced substantial frustration because the cells were detectable in the kidney for only two hours and then disappeared. But after entry into the kidneys with ARF, we found that they fundamentally changed a number of important gene expression profiles. In fact, the intrarenal location of administered stem cells is such that it facilitates the delivery of renoprotective growth factors and cytokines to the sites where kidney cells are primarily destroyed from both the blood and urinary aspects of the cells that must be protected and repaired! Westenfelder reported.

With their rapid mode of action within only two hours in the kidney, the researchers deduced that the mechanism mediating the protective effects of MSC (mesenchymal stem cells) must be primarily paracrine, as implied by their demonstrated expression of several growth factors such as HGF (hepatocyte growth factor), VEGF and IGF-1, all known to improve renal function in ARF, mediated by their antiapoptotic, mitogenic and other cytokine actions, the paper said.

Specifically, these as yet incompletely defined paracrine actions of MSC result in the renal downregulation of proinflammatory cytokines IL-1-beta, TNF-alpha, and IFN-gamma, as well as iNOS (inducible nitric oxide synthase), and upregulation of anti-inflammatory and organ-protective interleukin-10, as well as bFGF (basic fibroblast growth factor), TGF-alpha (transforming growth factor alpha) and antiapoptotic Bc1-2, the paper added.

Beneficial paracrine actions are elicited early and late after onset of ARF

The study said it provides the first clear evidence that therapy with MSC affords significant renoprotection in rats with ischemic/reperfusion (I/R) ARF. Animals infused with MSC either immediately or 24 hours after reperfusion had significantly better renal function, lower renal injury and cell-death scores, and higher cell division indices than vehicle-treated control animals, the paper stated. Indeed, administration after 24 hours of more severe ARF had an even greater beneficial effect.

Based on utilization of several genomic and nongenomic cell-tagging techniques, the researchers were able to follow the stem cells as they circulated through the renal microcirculation of two different strains of rats used in the experiments. Although we did not detect transdifferentiation events during the 72-hour period of observation, it is possible that cell transdifferentiation and integration may be important at later states of organ repair, the study noted.

The Utah team used MSC for several reasons, notably the fact that they can be harvested easily from bone marrow, isolated, grown in culture and genetically engineered. To test that MSC subsequently used in these studies retained their phenotype after being cultured, the researchers routinely tested whether their characteristic potential to differentiate into fat and bone cells was preserved.

The researchers conceded that it is surprising that the very transient presence of MSC in the injured kidney, as we document, is sufficient to greatly ameliorate the course of I/R ARF and also note that the rat model of ARF used in the study is a suitable if somewhat imperfect model of the most common and the most treatment-resistant type of human ischemic ARF.

Adipose tissue stem cells could be used to treat injured or damaged tissues

Sun, 04 Sep 2005 08:23:38 PST

( from http://www.rxpgnews.com ) National and international scientists, including those from the University of Virginia Health System, will announce findings from a significant number of studies showing that adult stem cells from adipose tissue (fat) could eventually be used to treat injured or damaged tissues. They will present their research findings at the Omni Hotel in Charlottesville, Virginia, September 10-13, during the third annual International Fat Applied Technology Society conference, The Role of Adipose Tissue in Regenerative Medicine: Opportunities for Clinical Therapy. Reporters are invited to attend and a press room will be open to meet their needs.

In total, 47 research abstracts will be presented from both academia and the private sector. Findings suggest that adipose-derived stem cells can be used to repair or regenerate new blood vessels, cardiac muscle, nerves, bones and other tissue, potentially helping heart attack victims, patients with brain and spinal cord injuries and people with osteoporosis. The work to be presented reflects a growing number of researchers who believe that adipose tissue (fat) will be a practical and appealing source of stem cells for regenerative therapies of the future.

"Five years ago we were seen as mavericks," says Dr. Adam Katz, plastic surgeon at the University of Virginia Health System, co-founder and president of the International Fat Applied Technology Society, and conference coordinator. "Now there is a sense of validation and growing enthusiasm from an increasing number of international researchers who view adipose tissue as a potentially valuable source of therapeutic cells."

Fusing adult somatic cells with embryonic stem cells - New Technique

Mon, 22 Aug 2005 21:40:38 PST

( from http://www.rxpgnews.com ) Researchers have developed a new technique for creating human embryonic stem cells by fusing adult somatic cells with embryonic stem cells. The fusion causes the adult cells to undergo genetic reprogramming, which results in cells that have the developmental characteristics of human embryonic stem cells.

This approach could become an alternative to somatic cell nuclear transfer (SCNT), a method that is currently used to produce human stem cells. SCNT involves transferring the nuclei of adult cells, called somatic cells, into oocytes in which scientists have removed the nuclei.

The researchers said that -- while the technique might one day be used along with SCNT, which involves the use of unfertilized human eggs -- technical hurdles must be cleared before the new technique sees widespread use. It is more likely that the new technique will see immediate use in helping to accelerate understanding of how embryonic cells "reprogram" somatic cells to an embryonic state.

The researchers published their findings in the August 26, 2005, issue of the journal Science. Senior author Kevin Eggan and Howard Hughes Medical Institute investigator Douglas A. Melton, both at Harvard University, led the research team, which also included Harvard colleagues Chad Cowan and Jocelyn Atienza.

In theory, researchers can induce embryonic stem cells to mature into a variety of specialized cells. For that reason, many researchers believe stem cells offer promise for creating populations of specialized cells that can be used to rejuvenate organs, such as the pancreas or heart, that are damaged by disease or trauma. Stem cells also provide a model system in which researchers can study the causes of genetic disease and the basis of embryonic development.

Eggan, Melton and their colleagues decided to pursue their alternative route after other researchers had shown that genetic reprogramming can occur when mouse somatic cells are fused to mouse embryonic stem cells. The scientists knew that if their studies were successful, it would provide the research community with a new option for producing reprogrammed cells using embryonic stem cells, which are more plentiful and easier to obtain than unfertilized human eggs.

In the studies published in Science, the researchers combined human fibroblast cells with human embryonic stem cells in the presence of a detergent-like substance that caused the two cell types to fuse. The researchers demonstrated that they had achieved fusion of the two cell types by searching the fused cells for two distinctive genetic markers present in the somatic fibroblast and stem cells. The researchers were also able to further confirmed that fusion occurred by studying the chromosomal makeup of the fused cells. Their analyses showed that the hybrid cells were "tetraploid" meaning they contained the combined chromosomes of both the somatic cells and the embryonic stem cells.

One of the key findings from the study was that the fusion cells have the characteristics of human embryonic stem cells. "Our assays showed that the hybrid cells, unlike adult cells, showed the development potential of embryonic stem cells," said Eggan. "We found they could be induced to mature into nerve cells, hair follicles, muscle cells and gut endoderm cells. And, since these cell types are derived from three different parts of the embryo, this really demonstrated the ability of these cells to give rise to a variety of different cell types."

Furthermore, Eggan noted that genetic analyses of the fused cells revealed that the somatic cell genes characteristic of adult cells had all been switched off, while those characteristic of embryonic cells had been switched on. "With the exception of a few genes one way or the other -- which is perhaps because these cells are now tetraploid -- the hybrid cells are indistinguishable from human embryonic stem cells," he said.

"The long term goal for this experiment was to do cell fusion in a way that would allow the elimination of the embryonic stem cell nucleus to create an embryonic stem cell from the somatic cell," said Melton. "This paper reports only the first step toward that goal, because we end up with a tetraploid cell. So, while this does not obviate the need for human oocytes, it demonstrates that this general approach of cell fusion is an interesting one that should be further explored."

The researchers also performed fusion experiments using pelvic bone cells as the somatic cells and a different human embryonic cell line, to demonstrate that their technique was not restricted to one adult cell type or embryonic cell line.

In both cases, the researchers observed extensive reprogramming of the somatic cells. "We were surprised at how complete the reprogramming was," said Eggan. "I think we were expecting that there would be more 'memory' of the adult state than the embryonic in the hybrid cells. It was quite clear that when we looked at these hybrid cells, they had completely reverted to an embryonic state."

Melton said that the remaining technical hurdle is figuring out a way to eliminate the embryonic stem cell nucleus in the hybrid cell, causing it to have a normal number of chromosomes. One problem, said Melton, is that the nucleus in stem cells is large, occupying nearly the entire cell. Thus, it is not practical to physically extract the nucleus, as is currently done with oocytes, which have a relatively small nucleus. An alternative approach of destroying the embryonic stem cell nucleus with chemicals or radiation would induce the cell's suicide program, called apoptosis, he said.

Melton emphasized that "at this at this stage in our understanding, the hard fact is that the only way to create an embryonic stem cell from a somatic cell is by nuclear transfer into oocytes. Taking advantage of this current capability -- such as colleagues in South Korea and other countries are doing -- is critical if we are to maintain the progress necessary to realize the extraordinary clinical potential of this technology."

Eggan added that the most realistic current promise of the fusion technique is in studying the machinery of genetic reprogramming of somatic cells by embryonic cells. "It is extremely difficult to study the reprogramming process using eggs, because in the case of humans it is very difficult to obtain eggs in any quantity and difficult or impossible to genetically manipulate them," he said. "But embryonic stem cells can be grown in large quantities. We can isolate the components of the reprogramming machinery, and we can genetically manipulate the cells to analyze the reprogramming process."

Method to produce symmetrical divisions of mouse brain stem cells derived from ES cells

Fri, 19 Aug 2005 18:51:38 PST

( from http://www.rxpgnews.com ) In all the hullabaloo about stem cells, nobody has noted their uncanny similarity to pizza dough. You can divide either into two or four or eight identical pieces, but that doesnt determine what kind of cell or pizza you're going to make. But once you let a cell grow hundreds of nuclei, or you pile on the pepperoni, youre on your way to making a skeletal muscle fiber or a pepperoni pizza. If you want a white blood cell or an all-veggie pie, youre out of luck. The commitment to becoming a certain cell type is called differentiation.

Stem cells in living organisms can multiply without differentiating, preserved by molecular signals in special niche environments; without these signals in the petri dish, they differentiate. Pluripotent mouse embryonic stem (ES) cells, a special type of stem cell with the potential to develop into many different cell types, are an exception. Because they divide symmetrically, the scads of artificially grown ES cells are all the same. This leads researchers to wonder: what conditions in the body keep stem cells from differentiating, why are ES cells the only kinds that dont differentiate in the petri dish, and how can scientists create undifferentiated tissue-specific stem cells in the lab?

In a new paper, Austin Smith and colleagues developed a method to produce symmetrical divisions of mouse brain stem cells derived from ES cells. Their novel method creates an on/off switch for differentiation of tissue-specific stem cells: they can multiply without differentiation, and they can also become normal brain cells. The authors also managed to cultivate the brain stem cells without re-creating the rarefied neurosphere, the highly specialized environment or microenvironment in which the body grows its own brain stem cells.

Many scientists believe that in the body, these microenvironments prevent stem cells from differentiating. Neurospheres, for example, contain some undifferentiated brain stem cells floating in a broth of differentiating cells. One feature of the neurosphere is that a very low percent of cells are brain stem cells. In fact, neurospheres have so few of these cells that scientists have a hard time even observing them! But by cultivating brain stem cells outside the neurosphere, the scientists showed that a complex microenvironment may not be necessary. To grow their stem cells, Smith et al. combined epidermal growth factor (EGF) and fibroblast growth factor (FGF), two small proteins that bind to stem cells and promote growth.

Previously, scientists had grown brain stem cells with FGF. Upon removing FGF, the cells failed to differentiate and become mature. The cells that Smith et al. grew, in contrast, became mature cells upon removal of the growth factor cocktail. They observed both neurons and astrocytes, the two types of cells into which the brain stem cells mature.

In the future, scientists may use this new technique to produce large quantities of the cells to study their basic properties and also to explore their value for modeling neurodegenerative afflictions, including Huntington disease, Parkinson disease, and Alzheimer disease. Additionally, these cells may clinch the debate of whether doctors will be able to use stem cells directly to repair brain damage.

Producing embryonic-like cells from umbilical cord blood

Thu, 18 Aug 2005 13:38:38 PST

( from http://www.rxpgnews.com ) A breakthrough in human stem cell research, producing embryonic-like cells from umbilical cord blood may substantially speed up the development of treatments for life-threatening illnesses, injuries and disabilities. The discovery made during a project undertaken with experts from the University of Texas Medical Branch and the Synthecon Corporation in the United States provides medical researchers and physicians with an ethical and reliable source of human stem cells for the first time.

The study, funded by the UK Government's Department of Trade and Industry, is led by Dr Colin McGuckin and Dr Nico Forraz from Kingston University's School of Life Sciences. It represents a significant step forward in the fast-developing field of stem cell research. Until now, experts have struggled to find a supply of cells in sufficient numbers that does not offend previous critics of stem cell research. The latest advance looks set to overcome such difficulties.

The trans-Atlantic team has been working with Drs Randall Urban, Larry Denner and Ronald Tilton from the University of Texas Medical Branch in Galveston. They have been using bioreactors at the Synthecon Corporation base in Houston enabling them to produce stem cells sharing many of the same characteristics as cells found in embryos. Research has so far relied on so-called adult cells found in blood and bone marrow from birth onwards or cells grown from embryos. The new type detected by the team harnesses the benefits of both. "We have found a unique group of cells that bring together the essential qualities of both types of stem cells for the first time," Dr McGuckin said.

The researchers findings may bring renewed hope to people awaiting treatment for a range of serious illnesses such as Diabetes, Alzheimer's Disease and multiple sclerosis. "Acquiring stem cells from embryos also has major limitations because it is difficult to obtain enough cells to transplant as well as getting the right tissue type for the patient," Dr McGuckin said. "Using cord blood gets over that obstacle because we can produce more stem cells and, with a global birth rate of 100 million babies a year, there is a better chance of getting the right tissue type for the many patients out there waiting for stem cell therapy. There is also far less likelihood of such cells being rejected when they are transplanted into people with liver disease, for example."

The team has taken its first steps towards proving its claims by growing defined liver tissue using the new cell type. By making use of special NASA-derived technology, the team is able to cultivate greater numbers of cells in equipment mimicking the effects of space microgravity. "Using Synthecon's bioreactors, originally designed by NASA, means the cells are able to expand faster, giving us a greater supply to work with," Dr Forraz said. "This system provides more cells for more tests, so we have the potential to make significant progress in applying the new cells to cure difficult to treat conditions such as juvenile diabetes, stroke, heart and liver disease."

Dr Urban who chairs UTMB's Internal Medicine department and serves as director of its Stark Diabetes Centre said he looked forward to the next phase of what was proving to be a fruitful collaboration. "We plan to use this technology to engineer pancreatic tissue as we work towards our goal of developing a cure for type 1 diabetes," he added.

Promising cells similar to embryonic stem cells from amnion

Sat, 06 Aug 2005 16:52:38 PST

( from http://www.rxpgnews.com ) Routinely discarded as medical waste, placental tissue could feasibly provide an abundant source of cells with the same potential to treat diseases and regenerate tissues as their more controversial counterparts, embryonic stem cells, suggests a University of Pittsburgh study to be published in the journal Stem Cells and available now as an early online publication in Stem Cells Express.

A part of the placenta called the amnion, or the outer membrane of the amniotic sac, is comprised of cells that have strikingly similar characteristics to embryonic stem cells, including the ability to express two key genes that give embryonic stem cells their unique capability for developing into any kind of specialized cell, the researchers report. And according to the results of their studies, these so-called amniotic epithelial cells could in fact be directed to form liver, pancreas, heart and nerve cells under the right laboratory conditions.

"If we could develop efficient methods that would allow amnion-derived cells to differentiate into specific cell types, then placentas would no longer be relegated to the trashcan. Instead, we'd have a useful source of cells for transplantation and regenerative medicine," said senior author Stephen C. Strom, Ph.D., associate professor of pathology at the University of Pittsburgh School of Medicine and a researcher at the university's McGowan Institute for Regenerative Medicine.

According to U.S. census figures, there are more than 4 million live births each year. For each discarded placenta, the researchers calculate there are about 300 million amniotic epithelial cells that potentially could be expanded to between 10 and 60 billion cells relatively easily.

"Provided that research advances to the point that we can demonstrate these cells' true therapeutic benefit, parents could conceivably choose to bank their child's amniotic epithelial cells in the event they may someday be needed, as is sometimes done now with umbilical cord blood," commented Dr. Strom.

The amnion is derived from the embryo and forms as early as eight days after fertilization, when the fate of cells has yet to be determined, and serves to protect the developing fetus. According to the researchers' studies using placentas from full-term pregnancies, amniotic epithelial cells have many of the telltale surface markers that define embryonic stem cells, and also express the Oct-4 and nanog genes that are known to be required for self-renewal and pluripotency the ability to develop into any type of cell.

Yet the authors are careful to point out that despite their remarkable similarities to embryonic stem cells, amniotic epithelial cells are not stem cells per se, because they can't grow indefinitely. This may be due to the fact that these amnion-derived cells do not express a certain enzyme, called telomerase, that is important for normal DNA and chromosome replication, and by extension, ultimately, cell division.

"Perhaps it's to their advantage that the amnion epithelial cells lack telomerase expression, because telomerase is associated with many cancers and one of the main concerns about stem cell therapies is that transplanted stem cells would replicate in the recipient to form tumors," noted Toshio Miki, M.D., Ph.D., first author of the paper and an instructor in the department of pathology at the School of Medicine.

To help determine if amnion-derived cells that are delivered directly to tissues would cause tumors, the researchers conducted studies in immune system-deficient mice and found no evidence that tumors had developed seven months after the cells were injected into multiple sites.

While amniotic epithelial cells do not share the same capacity for unlimited replication as do embryonic stem cells, they still can double in population size about 20 times over without needing another cell type serving as a feeder cell layer. This is significant, because to replicate, the currently available embryonic stem cell lines require a bed of mouse cells, traces of which can end up in each new generation of stem cells. Amniotic epithelial cells, on the other hand, create their own feeder layer, with some cells choosing to spread out at the bottom of the culture dish thereby giving those cells just above them the best environment for replicating and for retaining their stem cell characteristics.

With the addition of various growth factors, the authors report the amnion-derived cells could differentiate to become liver cells, heart cells, the glial and neuronal cells that make up the nervous system, and pancreatic cells with genetic markers for insulin and glycogen production.

"In this first paper we sought to determine if amniotic epithelial cells have the potential to differentiate into many different cell types rather than focusing on ways for optimizing this potential for a specific cell type. Further studies will be required to better understand if and how they may be useful in a clinical setting," Dr. Strom added.

The researchers say their original motivation was, and still is, to identify cells with the same therapeutic promise as embryonic stem cells. To this end, they began looking at the viability of amnion as a cell source in late 2001, obtaining discarded placentas from full-term births under an Institutional Review Board-approved protocol. In 2002, the University of Pittsburgh licensed the technology to a company now called Stemnion, LLC, and as part of the agreement, and in keeping with university patent policy, Drs. Strom and Miki will receive license proceeds. Both have served as paid consultants and hold equity in Stemnion.

Study - how cells become specialized for secretion

Wed, 27 Jul 2005 13:19:38 PST

( from http://www.rxpgnews.com ) Johns Hopkins researchers have discovered that a single protein regulates secretion levels in the fruit flys salivary gland and its skin-like outer layer.

Described in the May 15 issue of Development, the finding improves understanding of how cells become specialized for secretion, which is a critical ability of certain glands and cell types in organisms from insects to humans.

The researchers discovered that a protein called CrebA single-handedly controls the entire set of events leading to secretion in the fruit flys salivary gland and epidermis, its skin-like outer layer.

CrebA, or a closely related human gene, might play the same role in certain human cells, too, the researchers say.

In juvenile (type I) diabetes, for example, pancreatic cells that normally produce and secrete insulin don't work, and stem cells might be able to help fix that problem, the researchers note. The key is knowing how pancreatic cells know what hormones to produce and release, or how any gland does, and the new findings add to that knowledge, says Deborah Andrew, Ph.D., professor of cell biology in Johns Hopkins' Institute for Basic Biomedical Sciences.

Curiosity brought Andrew and Elliott Abrams, then a graduate student, to focus on secretion in the salivary gland, the largest glandular organ in the fruit fly embryo, approximately six years ago. In humans and in fruit flies, the gland secretes saliva, a fluid containing water, mucus, electrolytes, and food-dissolving enzymes, into the mouth, and is important to the digestive system.

In their new experiments, the researchers looked at the expression of 34 secretory genes in a normal fruit fly embryo to see which genes were turned on when. All 34 genes were expressed at high levels in the early salivary gland, they found. According to Andrew, This suggests the salivary gland becomes programmed for secretion because all the components required to allow secretion to occur are turned on very early in development.

In order for any gene's instructions to be used to make a protein, the process of reading the instructions is jump-started by proteins called transcription factors. In the salivary gland, the researchers found two of these proteins that controlled secretory gene expression in the salivary gland: CrebA (Cyclic-AMP response element binding protein A) and Fkh (Fork head).

CrebA is required for the expression of the secretory genes throughout development, while Fkh appears to be required only in later embryonic stages. The group has shown that Fkh is required to maintain expression of CrebA in the salivary gland. CrebA is the more immediate factor involved in keeping secretory genes expressed at high levels, and Fork head acts through it, said Andrew.

CrebAs role in the fruit flys epidermis gives it secretion-promoting powers there as well, the researchers note. In fruit flies, epidermal cells secrete the cuticle, a protective covering for the organism.

Our findings suggest that this single transcription factor directly determines the amount of secretory activity in a given cell type, said Andrew.

New chemical to accelerate stem cell mobilization

Wed, 27 Jul 2005 13:15:38 PST

( from http://www.rxpgnews.com ) The finding has led to the development of a new chemical compound that can accelerate this process (called stem cell mobilization) in mice--which could eventually lead to more efficient stem cell harvesting for human use.

The researchers, from the Cincinnati Children's Hospital Medical Center and the University of Cincinnati (UC), studied the migration of mouse stem cells to better understand how adult cells move into the bone marrow during stem cell transplants--or can be directed into the blood stream, where they can be more easily harvested for use in transplant procedures.

The team, led by Jose Cancelas, MD, PhD, and David Williams, MD, found that a group of proteins known as the RAC GTPase family plays a significant role in regulating the location and movement of stem cells in bone marrow.

Dr. Cancelas, lead author of the report, is director of research at UC's Hoxworth Blood Center. Dr. Williams, the senior author, heads experimental hematology at Cincinnati Children's.

The researchers discovered that by inhibiting RAC GTPase activity in mice, they were able to "instruct" stem cells to move from their home in the bone marrow and into the blood stream, where they can easily be collected. They achieved this using a drug, developed by Cincinnati Children's faculty member Yi Zheng, PhD, known as NSC23766.

Their findings are reported in the Aug. 6 edition of the scientific journal Nature Medicine.

Scientists have long known that bone marrow stem cells regenerate blood cells. Recent research has also suggested that these cells may help repair damage in other organs, such as the heart and brain.

Injected during transplants procedures, stem cells migrate to a specific location in the bone marrow, where they reestablish the mechanism of blood formation.

"Our findings demonstrate that RAC GTPase proteins are essential for injected stem cells to migrate into the correct location in the bone marrow," said Dr. Williams.

Researching the location of and the factors involved in stem cell regeneration is important to the development of new therapeutic tools in stem cell therapy, said Dr. Cancelas, lead author of the report.

"We wanted to know why stem cells are located in specific pockets of the bone marrow," he said, "and how can they be mobilized to move into the blood stream for easier collection."

Adult stem cell transplantation, or bone marrow transplantation, is used during the treatment of cancer and genetic blood diseases, such as sickle cell anemia, to restore blood cell formation in bone marrow that has been damaged by high-dose chemotherapy or radiation therapy. It has also shown promise in animal studies for possible treatment of organ damage, such as that seen in heart disease and degenerative diseases like Parkinson's.

During high-dose radiation therapy treatment, given to kill advanced cancer, normal stem cells found in bone marrow are also destroyed. Without a bone marrow transplant, new blood cells cannot be produced and the patient will die.

When bone marrow or adult stem cells are taken from a matching donor and injected into the patient after radiation or chemotherapy, the cells move through the recipient's blood stream and settle in the same type of tissue they inhabited in the donor.

Although bone marrow is the best known reservoir of stem cells, only one of 100,000 cells in the marrow is a stem cell. There are also small reservoirs of stem cells in other major organs, such as brain, muscle, heart and other tissue.

The research team also included Andrew Lee, Rethinasamy Prabhakar, PhD, and Keith Stringer, MD, PhD. Their work was supported by grants from the National Institutes of Health and the National Blood Foundation.

More than 40,000 bone marrow transplants are performed each year worldwide, about 25,000 using the recipient's own tissue, and 15,000 using tissue from matching donors.

Discovery of adult stem cells in the uterus

Fri, 22 Jul 2005 16:43:38 PST

( from http://www.rxpgnews.com ) Monash Institute of Medical Research (MIMR) senior scientist Dr Caroline Gargett's discovery of adult stem cells in the uterus that can be grown into bone, muscle, fat and cartilage, has been hailed as a major medical and scientific development by international reproduction experts.

Taking out a major award at the recent European Society for Human Reproduction and Embryology (ESHRE) conference in Copenhagen, one of the most prestigious meetings in this field, Dr Gargett explained how two types of adult stem cells have been extracted from endometrial tissue in the uterus.

"While adult stems cells have been found in other parts of the body, no-one has ever identified them in the uterus before," said Dr Gargett, a senior scientist in the Centre for Women's Health Research at MIMR. "Not only will this assist with understanding how several diseases of the uterus develop, but could also further general studies into adult stem cells."

"The discovery of mesenchymal stem cells is particularly significant as it is from this type of stem cell that bone, muscle, fat and cartilage are formed," she said. "We can now grow these tissues in the lab and are investigating avenues to apply the technology."

The initial focus of this team at MIMR is on using these stem cells to aid the repair of pelvic floor prolapse.

"If we could offer women a bioengineered ligament that is made from their own stem cells, the long term quality of life for the thousands of women who suffered from this problem could be greatly enhanced," she said.

Monash Medical Centre Urogynaecologist Dr Anne Rosamilia agrees that such a development could be significant.

"About one in ten women require treatment for uterine prolapse, usually in their 50s and older, although it can happen to younger women. The pelvic floor is weakened during pregnancy and childbirth and as a woman ages the strength of these muscles can deteriorate further," Dr Rosamilia explained.

"At present we use surgery to repair prolapsed uterus, which is a form of hernia," she said. However, in almost 30% of women the prolapse can reoccur. In order to reduce this chance of a recurrence a reinforcement material, often a synthetic mesh is applied. . While this technique can be successful, complications also frequently arise due to erosion or rejection of the foreign matter. A firm natural tissue would certainly be advantageous."

The development of this new treatment for pelvic floor problems is in its early stages, however the significance of this Australian discovery is being widely acknowledged around the world.

Does the Heart Contain Stem Cells?

Fri, 22 Jul 2005 00:54:38 PST

( from http://www.rxpgnews.com ) Steven Houser, Ph.D., Director of Cardiovascular Center for Temple University School of Medicine and Senior Associate Dean of Research, is sold on the idea that the heart - like the skin - contains its own stem cells: cells that are self-renewing and can be differentiated into different types of heart tissue. It's a controversial subject in cardiovascular circles, but for Houser, who spent thirty years studying the molecular biology of heart cells, the stakes are worth it when it comes to combating congestive heart failure (CHF).

CHF, which afflicts 4.8 million Americans, occurs when the heart no longer has the strength to pump blood efficiently, resulting in an increasingly diminished quality of life. While a wide variety of well-understood conditions such as high blood pressure or excess weight can lead to CHF, a cure for the debilitating disease is less clear. Invasive surgical procedures such as a bypass operation or the insertion of a stent can extend a patient's life, but the essential damage to the heart caused by the condition remains. Pharmacological therapies to improve the function of cardiac muscle cells improve heart function, but the treatments often lead to fatal arrhythmias, canceling out any benefits. To Houser, the problem proved frustrating.

"Cells were dying in the heart and there were simply not enough new cells to replace them," he says. "They were tired soldiers who could no longer work efficiently, and there were no new soldiers coming to take their place."

Although stem cells have been found in many other organs in the body, including the brain, many cardiac researchers remain unconvinced that the heart contains stem cells. For one, stem cells can over multiply and cause tumors, and the heart rarely gets tumors. These facts and the observations that adult cardiac myocytes do not have the capacity to proliferate have led most investigators to accept the dogma that no new cardiac myocytes are manufactured in the normal heart.

Houser respectfully disagrees. Abandoning his prior cell research, he joined forces with one of the foremost investigators in cardiac stem cells, Pierro Anversa, Ph.D. professor of medicine and Director of the Cardiovascular Institute at the New York Medical College at Valhalla, New York. Anversa, who has been on the forefront of stem cell research for the past five years, has suggested that heart cells undergo an ongoing turnover fueled by cardiac stem cells. In June of this year, Anversa published a study that actually identified cardiac stem cells in animal models that repaired tissue damaged by a heart attack.

One element that convinced Houser of Anversa's work was his own research into how the heart reacts under the stress of hypertensive diseases that can lead to congestive heart failure. Early in the disease, the heart muscle mass increases and the chambers stretch in a vain attempt to increase contracting power. While part of the enlargement is due to increased muscle mass, the question of how the chambers grow is less certain.

The traditional view holds that cardiac cells simply grow larger to accommodate the increased need, but Houser and Anversa developed a different theory - that spurred by the cardiac stem cells, cardiomyocytes actually increase in number in their response to the heart's traumatic condition.

"It was striking that with hypertension there were actually more cardiomyocytes than were originally lost," says Houser. "New myocytes were forming in excess of the cells that were dying."

And if that were true, these were the new soldiers to replace those missing in action.

To test this theory, Houser, with the help of Anversa, has received a new NIH grant to study if there are autologous stem cells in the heart. The two researchers have arrived at a deceptively simple idea. After inducing hypertension in an animal model to produce a distressed heart they will study the heart tissue and count cells, first in the normal heart and then in a heart that must work harder to develop excess pressure. If, according to the scientists' thesis, there are more cardiomyocytes in the heart as opposed to simply larger cells, they will conclude that stem cells had a hand in an attempt to repair and restore the heart.

If their hunch proves correct, the implications for treatment of heart disease are profound. In the future, for example, Houser envisions people banking their own stem cells, so that when a problem arises, new tissue can be made by injecting these cells into the damaged heart. The idea is simple, use the patients own cardiac stem cells to repair their damaged heart.

"We've made a tremendous impact on cardiovascular diseases such as congestive heart failure through the hard work of physicians, better service, stents and bypasses," he says. "But what we need to do now is to reverse this disease rather than just slow its progression."

Although his colleagues may remain skeptical, Houser has committed himself to the stem cell model. Inducing cells to promote repair can answer the question that has haunted his career.

"We don't know how to fix the broken heart, but stem cells might be a large part of the answer."

Unlimited mesenchymal precursor cells derived from human embryonic stem cell

Tue, 28 Jun 2005 01:05:38 PST

( from http://www.rxpgnews.com ) According to research published today, investigators from Memorial Sloan-Kettering Cancer Center (MSKCC) have used new techniques in the laboratory that allowed them for the first time to derive unlimited numbers of purified mesenchymal precursor cells from human embryonic stem cells (HESCs). Mesenchymal precursor cells are capable of giving rise to fat, cartilage, bone, and skeletal muscle cells, and may potentially be used for regenerative stem cell therapy in bone, cartilage, or muscle replacement.

The new study, demonstrating the specialized techniques for isolating mesenchymal precursors and generating, purifying, and differentiating those cells in culture, is published online and freely available in the journal PLoS Medicine (Public Library of Science).

Researchers took two lines of completely undifferentiated HESCs and by culturing them in the presence of mouse cells, stimulated them to turn into mesenchymal cells. They then treated these cells with compounds to make them change into specialized bone, cartilage, fat, and muscle cells. According to the study, researchers were able to confirm that these cells were all human cells and that there was no evidence that the cells became cancerous.

Mesenchymal precursors derived from HESCs are different from adult mesenchymal cells because they can efficiently differentiate into skeletal muscle (adult mesenchymal cells do not) in addition to fat, cartilage, and bone. Limited numbers of mesenchymal stem cells have been isolated from adult bone marrow and connective tissues, but harvesting these cells from any of these sources requires invasive procedures and the availability of a suitable donor. The capacity of these cells for long-term proliferation is also poor. In contrast, HESCs could provide an unlimited number of specialized cells.

According to Lorenz Studer, MD, PhD, Head of the Stem Cell and Tumor Biology Laboratory at MSKCC and senior author of the PLoS Medicine study, the high purity, unlimited availability, and multi-potentiality of mesenchymal precursors derived from HESCs will provide the basis for preclinical mouse studies to assess the safety of these cells. The investigators have already taken the next step in this research and are testing the therapeutic potential of embryonic stem cell-derived muscle cells in animal models of muscle disorders.

Human embryonic stem cells have the capacity to develop into eggs or sperm

Mon, 20 Jun 2005 16:31:38 PST

( from http://www.rxpgnews.com ) Scientists in the UK have proved that human embryonic stem cells can develop in the laboratory into the early forms of cells that eventually become eggs or sperm. Their work opens up the possibility that eggs and sperm could be grown from stem cells and used for assisted reproduction, therapeutic cloning and the creation of more stem cells for further research and for the improved treatments for patients suffering from a range of diseases.

Behrouz Aflatoonian will tell the 21st annual conference of the European Society of Human Reproduction and Embryology today (Monday 20 June) that the research also solves the practical and ethical problems associated with obtaining human samples of primordial germ cells (PGCs), which are the ancestral cells that eventually form eggs and sperm (gametes). "Investigating the mechanisms of human primordial germ cell and gamete development is important for understanding the causes of infertility and the potential harmful effects of environmental chemicals on reproductive development," he will say. "But at present it is very difficult to obtain human samples of these cells as they only occur early in development."

Mr Aflatoonian, who is a PhD student in Professor Harry Moore's laboratory at the Centre for Stem Cell Biology, University of Sheffield, UK, said that studies with mice embryonic stem cells had shown that they were capable of differentiating into PGCs and subsequently eggs and sperm, so he set out to see if the same applied to human embryonic stem cells (HESCs).

"We derived six embryonic stem cell lines from embryos donated for research under HFEA regulations by couples undergoing IVF treatment. In addition, we utilised cell lines from the University of Wisconsin.

"The human embryonic stem cells were allowed to develop into collections of cells called embryoid bodies. The embryoid bodies were tested to see which genes were active, or 'expressed', in them and it was found that within two weeks a very tiny proportion of cells in the embryoid bodies began to express some of the genes that are found in human primordial germ cells. Some cells also expressed proteins only found in maturing sperm. This suggests that HESCs may have the ability to develop into PGCs and early gametes as has been shown previously for mouse embryonic stem cells."

However, Mr Aflatoonian stressed that there was still a lot of work to be done before the promise of these early results could be translated into reality. "Embryoid bodies can differentiate into all sorts of tissue types, so we need to choose the cells that are going to develop into PGCs and then work out how we can encourage them to grow into gametes.

"Producing functional gametes is much more difficult, because we have to recreate for the cultured cells the environment of the developing follicle for egg development or the tissue of the testis for sperm. We want to test whether HESCs can differentiate to cells that produce the hormones for sperm and egg development and isolate these as well. What is extraordinary is that the embryoid bodies seem to produce spontaneously the tissue and environment conducive for sperm and egg development in quite a short time in culture."

Speaking before the conference, Prof Moore said: "One of the reasons for doing this research is that it may allow us to investigate the very earliest processes of how a human gamete and gonad (ovary and testis) develops. Many scientists believe that environmental chemical pollutants that mimic the action of hormones (so called endocrine disrupting chemicals) might interfere with human development at this stage and cause congenital abnormalities, infertility and possibly cancer (in particular testicular cancer). By developing suitable tests with embryonic stem cells as they differentiate to germ cells we can investigate the action of these chemicals in the laboratory.

"Ultimately it might be possible to produce sperm and eggs for use in assisted conception treatments. This is a long way off and we would have to prove it was safe because, for example, the culture process may cause genetic changes. For some men and women this would be the only route for producing sperm and eggs. It would not be reproductive cloning as fertilisation would involve only one set of gametes produced in this way and therefore a unique embryo would form.

"In addition, if we could produce eggs from HESCs they could also be used for therapeutic cloning (somatic nuclear replacement) circumventing the need for eggs from patients who donate them, as this is a major limitation of this technique at the moment. We would then have completed the circle of making HESCs from eggs that came from HESCs what came first the chicken or the egg?!"

Transplanted Spermatogonial Stem Cells Restores Fertility after Chemotherapy

Mon, 20 Jun 2005 10:43:38 PST

( from http://www.rxpgnews.com ) While more than 70% of patients survive childhood leukemia, curative chemotherapy can often irreversibly impair the formation of spermatozoa, causing infertility in males. Currently, the only established clinical option for the preservation of fertility in leukemia patients is to bank sperm before treatment commences. However, as mature germ cells do not develop until the onset of puberty, children are unable to later benefit from such assisted reproductive techniques. Although the transplantation of one's own germ cells after chemotherapy holds promise for restoring fertility, a major hurdle has been the risk of contamination by leukemic cells, which may induce relapse.

Now, in a study appearing online on June 16 in advance of print publication in the July 1 issue of the Journal of Clinical Investigation, Akira Tsujimura and colleagues from Osaka University describe a way in which healthy germ cells, including spermatogonial stem cells, can be distinguished and completely separated from leukemic cells in mice, and then harvested and preserved. These cells were then transplanted into the gonads of healthy recipient mice previously exposed to chemotherapeutic agents. The transplanted germ cells successfully colonized and were able to produce healthy progeny. The successful birth of offspring of recipient mice, without the transmission of leukemia to the recipient, suggests the potential of autotransplantation of carefully sorted germ cells in order to treat the infertility that arises as a result of anticancer treatment for childhood leukemia.

A number of issues surrounding the harvest of such material from prepubertal children with leukemia, that could be safely stored and retransplanted into chemotherapy-damaged testes, have not yet been solved.

These include:

( i ) the harvest of sufficient numbers of healthy germ cells, without significant tissue loss;

( ii ) careful isolation of germ cells, including stem cells, from the population of malignant cells to avoid relapse; and

( iii ) ensuring that isolated germ cells are able to undergo normal spermatogenesis. However, this overall approach may hold great potential for the treatment of infertility following recovery from childhood leukemia.

Canada's first two human embryonic stem cell lines developed

Thu, 09 Jun 2005 18:07:38 PST

( from http://www.rxpgnews.com ) A senior scientist at Mount Sinai Hospital has developed Canada's first two human embryonic stem cell lines, giving researchers across the country new potential and hope for eventually discovering treatments and cures for many chronic and fatal diseases.

"My hope and the hope of my world-class laboratory team is that our step of developing the first Canadian embryonic stem cell lines will ultimately bring Canada and the world closer to treating or curing diseases such as Multiple Sclerosis, Parkinson's Disease, Alzheimer's Disease, Diabetes and spinal cord injuries," said Dr. Andras Nagy, a researcher at Mount Sinai's Samuel Lunenfeld Research Institute.

"Our research remains in an early phase but the ability of these cells to develop into any kind of function cells in adult bodies holds enormous promise for these cells to regenerate damaged tissues that cause incurable diseases."

The Canadian Institutes of Health Research's Stem Cell Oversight Committee (SCOC) determined that Dr. Nagy derived these new stem cells lines in a manner consistent with the Stem Cell Guidelines.

The two cell lines have since been submitted to, and approved by, the International Stem Cell Initiative (ISCI). The use of the two new lines in Canada will be directed by the Stem Cell Network. The McLaughlin Centre for Molecular Medicine at the University of Toronto contributes to the support of a human embryonic stem cell core facility.

The stem cell lines will be freely available to the Canadian scientific community and will enable Canadian scientists to research potential treatments for a variety of diseases.

"Having our own cell lines gives Canadian researchers access to a valuable research tool. These two lines will be shared with scientists all over Canada and with the scientific community at large. They are a valuable contribution to stem cell research on a global scale," said Dr. Michael Rudnicki, Scientific Director of the Stem Cell Network.

Stem cell breakthrough in UK

Sat, 21 May 2005 14:34:38 PST

( from http://www.rxpgnews.com ) Newcastle University scientists have taken a major step forward in stem cell research, putting Britain in the vanguard of technology that could produce treatments for a range of conditions such as diabetes, Parkinsons disease and spinal injuries.

A team led by Dr Miodrag Stojkovic, based at the Centre for Life in Newcastle upon Tyne, announced that they have created a cluster of human cells, known as a blastocyst, by inserting DNA into an unfertilised human egg and inducing it to multiply.

This is the first step towards producing embryonic stem cells master cells that can form any tissue in the body, and which could be used to repair parts of the human body.

The team of University researchers work alongside the NHS-funded Life Fertility Centre at Newcastle, which supplies unfertilised eggs leftover from IVF treatment, with the consent of the donors.

The Newcastle team published details of their research simultaneously with a South Korean teams announcement that they have produced 11 batches of stem cells containing the genes of patients.

Oligodendrocyte Progenitors Show Functional Improvements in Spinal Cord Injuries

Wed, 11 May 2005 18:53:38 PST

( from http://www.rxpgnews.com ) Geron Corporation (Nasdaq:GERN) announced today the publication of studies showing that oligodendrocyte progenitors, differentiated from human embryonic stem cells (hESCs), produce functional improvements in rats with spinal cord injuries. These studies provide proof of concept for the therapeutic potential of differentiated hESCs in the treatment of neurological disorders such as spinal cord injury.

In the May 11 issue of the Journal of Neuroscience, Dr. Hans Keirstead and his colleagues from the Reeve Irvine Research Center at the University of California, Irvine published studies demonstrating that hESC-derived oligodendroglial progenitor cells (OPCs) could be delivered to the injured spinal cord in rats and resulted in functional improvement in locomotion as well as histological evidence of spinal cord repair.

Oligodendrocytes are normal cellular components of the central nervous system that wrap and insulate neurons in a process known as myelination. Such myelin wrapping enables efficient electrical transmission in neurons in the central nervous system. After spinal cord injury and the subsequent inflammatory response, native oligodendrocytes at the injury site die, leading to myelin destruction and consequent impaired electrical conduction even in those neurons that may have survived the initial injury. Demyelination of neurons leads to both sensory and motor deficits.

hESC-derived OPCs transplanted directly into the rat spinal cord injury survived and migrated appropriately both upstream and downstream from the lesion. Rats transplanted seven days after injury showed improved walking ability compared to animals receiving a control transplant. The OPC-treated animals showed improved hindlimb-forelimb coordination and weight bearing capacity, increased stride length, and better paw placement compared to control-treated animals. Such improvements in locomotor function were not observed when injured animals were treated ten months after injury, likely due to extensive scar formation which developed at the injury site in the months prior to OPC transplant. The studies document the potential therapeutic use of hESC-derived OPCs in acute spinal cord injury.

Microscopic examination of the spinal cords of OPC-treated animals showed evidence of spinal cord repair. Transplantation of the OPCs seven days after injury led to remyelination or "reinsulation" of demyelinated axons at the lesion site. Using labeled OPCs, the transplanted cells were visually observed to produce branches which wrapped the rat neurons. These results provide direct evidence for the structural tissue reparative function of these hESC-derived cells.

"Numerous studies have addressed the impact of demyelination in the pathophysiology of spinal cord injury," stated Thomas B. Okarma, Ph.D., M.D., Geron's president and chief executive officer. "The work published today demonstrates the potential for human embryonic stem cell-based therapies to restore normal physiological function by means of repairing tissue lost to injury or disease. We are currently engaged in preclinical development studies to ultimately enable testing of these cells in humans."

These studies in Dr. Keirstead's laboratory were conducted with support from Geron Corporation, a University of California Discovery Grant and the Roman Reed Spinal Cord Injury Fund of California.

Now a Stem Cell Therapy Targeted at Injured Tissue in Knee Surgery Patients

Sat, 02 Apr 2005 20:39:38 PST

( from http://www.rxpgnews.com ) Osiris Therapeutics, Inc. announced today that it has received clearance from the U.S. Food and Drug Administration to begin enrollment in the first human clinical trial for a stem cell therapy targeted at injured tissue in knee surgery patients. Chondrogen(TM), a formulation of adult mesenchymal stem cells, will be evaluated in a forty-eight patient, randomized trial to be conducted at the University of Southern California's University Hospital. The Phase I/II study will evaluate the safety and efficacy of the stem cell treatment for the regeneration of meniscus.

"Given the complexity of considerations involved in a stem cell clinical trial, I am proud that our team has been able to once again provide the FDA with the data necessary to move a product into the clinic," said C. Randal Mills, Ph.D., President and CEO of Osiris. "They did an excellent job conducting and compiling a large amount of research. Our focus now turns to executing the clinical trial." Chondrogen joins Prochymal(TM) and Provacel(TM) in the family of stem cell products under human clinical testing by Osiris.

In the U.S. alone, approximately 800,000 people each year have surgery to remove a portion of damaged meniscus, a cartilage-like tissue in the knee that acts as a shock absorber. In several large animal studies, Chondrogen has demonstrated the potential to regenerate the excised meniscus, as well as prevent the typical progression to osteoarthritis associated with this procedure.

"Patients who require removal of their damaged meniscus are at a much higher risk of developing arthritis," said C. Thomas Vangsness, MD, Professor of Orthopedic Surgery at USC's Keck School of Medicine and Chief of Sports Medicine at University Hospital. "To provide my patients the opportunity to regrow their own, naturally functioning meniscus would be revolutionary for the treatment of knee injuries and for the practice of sports medicine." Dr. Vangsness will serve as the Principal Investigator in the trial.

Regarding the relationship with USC, Mills said, "We are honored to be working with an institution of such high caliber. With their clinical expertise and Osiris' technology and resources, this study will be the foundation for a future pivotal trial and eventual product launch."

Chondrogen, which has been in development at Osiris since 1999, has shown encouraging preclinical results that served as the basis for FDA's decision to allow the first human treatments with the therapy. "The evidence suggests that a simple injection of MSCs into the knee has the potential to regenerate healthy meniscus," said Dr. Vangsness. "If these results are confirmed in humans, the impact will be enormous."

Adult Mesenchymal Stem Cells (MSCs) will Help Treat the Consequences of Heart Attack

Fri, 01 Apr 2005 09:27:38 PST

( from http://www.rxpgnews.com ) Osiris Therapeutics, Inc. announced today that is has begun a multi-center, randomized clinical trial with Provacel(TM), a novel therapeutic based on adult mesenchymal stem cells (MSCs).

"We are extremely enthusiastic about this study which represents the first use of an allogeneic adult stem cell to treat the consequences of heart attack in humans. The trial design is supported by an extensive series of preclinical studies performed in animal models that demonstrate that MSCs safely and effectively reduce the damage caused by heart attack," said lead investigator Dr. Joshua Hare, Director of Heart Failure and Cardiac Transplantation and the Cardiobiology Section of the Institute for Cell Engineering at Johns Hopkins University School of Medicine.

Enrollment in the Phase I study began March 24. It is being conducted in accordance with U.S. Food and Drug Administration guidelines, and is designed to evaluate safety and investigate the therapeutic benefits of treatment with allogeneic adult MSCs.

"Our investigators, hospitals, and team have worked exceptionally well together to advance the trial to this point," said C. Randal Mills, PhD, President and CEO of Osiris Therapeutics. "We remain committed to bringing this and other revolutionary treatments to patients who need them, while making every effort to ensure their safety by conducting tightly controlled clinical studies."

Osiris is evaluating Provacel with pioneers in the cardiac research field at leading U.S. institutions. "We are investigating an exciting new approach to address the unmet needs of cardiac patients," said Dr. Nabil Dib, Chief of Cardiovascular Research at the Arizona Heart Institute, another investigator in the trial.

"According to the American Heart Association, about two thirds of heart attack patients never completely recover. This is due to the fact that heart cells can't repair themselves, so we have to try innovative ways to treat the damage that occurs at the time of heart attack. If the research conducted to date is any indication, mesenchymal stem cells may be the answer."

Provacel is a formulation of MSCs shown to repair damaged tissue. A unique benefit of the product is that it is given to patients through a standard IV line. The delivered cells, responding to the body's own signals, migrate to the area of injury. Osiris recently became the first company to receive Fast Track designation from FDA for a similar stem cell product, Prochymal(TM), for the treatment of graft versus host disease in cancer patients.

Trial of adult mesenchymal stem cells to repair muscle damaged by heart attack

Sun, 27 Mar 2005 16:17:38 PST

( from http://www.rxpgnews.com ) Researchers at Johns Hopkins have begun what is believed to be the first clinical trial in the United States of adult mesenchymal stem cells to repair muscle damaged by heart attack, or myocardial infarct.

The so-called Phase I study is designed to test the safety of injecting adult stem cells at varying doses in patients who have recently suffered a heart attack.

An estimated 7 million Americans alive today have suffered at least one heart attack and so are at greater risk for chronic heart failure, sudden cardiac death or another, potentially fatal, heart attack.

"This is an important milestone on the journey to better cardiovascular care and to realization of the promise of adult stem cell research," says lead study investigator and cardiologist Joshua Hare, M.D., professor of medicine at The Johns Hopkins University School of Medicine and its Heart Institute.

"Current approaches to cardiovascular disease can prevent heart attack or alleviate its after-effects, but they have not included repair of damage that leaves sizably dead portions of heart tissue as dangerous scars in the heart," says study co-investigator and cardiologist Steven Schulman, M.D., a professor at Hopkins and director of the coronary care unit at The Johns Hopkins Hospital.

Previous research in animals showed that when adult stem cells were injected directly into the heart muscle, heart function was restored to its original condition within two months. Last November, at the American Heart Association Scientific Sessions 2004, the Hopkins team showed, again in animal studies, that more than 75 percent of dead scar tissue disappeared after therapy, which produced mostly healthy, normal-looking heart tissue and left only a small trace of the heart attack.

The Phase I study is being conducted at Hopkins, with support from Baltimore-based Osiris Therapeutics, which developed the stem cell product. The study will involve 48 adults who have had their first heart attack within 10 days of enrollment in the trial. All patients will have been stabilized before acceptance to the trial, and have undergone cardiac catheterization and ultrasound echocardiography to check that their main coronary vessels are clear of blockages that may precipitate another heart attack.

Eligible candidates must be able to safely travel to Hopkins Hospital in Baltimore, Md., be referred by a physician, be between 21 and 85 years old, and have no pre-existing heart condition that has been treated or requires treatment during the study period. Physicians interested in referring patients should call tel. 410-955-1160 for further information.

Upon acceptance in the study, patients will be randomly assigned to one of four groups, each made up of 12 patients who will receive a preset dose of stem cell therapy or placebo. The study is double blinded, with neither researchers nor patients aware of who received stem cells until the Phase I study ends, six months after the last patient has enrolled.

After injecting stem cells taken from the bone marrow of an adult, human donor, into subjects' bloodstream, the researchers will monitor the patient's progress for two years to ensure that patients safely tolerated the infusion, determine any side effects and assess any differences in the three doses under study, each involving millions of adult stem cells. Initially, study participants will spend four days in the hospital, immediately after the procedure. The patients will then return for preset checkups, monthly for the first three months, and again after six months, 18 months and 24 months.

Magnetic resonance imaging (MRI) studies, to show the size of the area of heart muscle scarred by the infarct and gauge the organ's ability to pump, will be conducted at the beginning and end of the study as a measure of heart function. Conclusive results will only be available when and if Phase II and Phase III clinical trials proceed.

The Hopkins team expects that after injection, the adult stem cells will migrate to the damaged areas of the heart muscle, responding to chemical signals released by the heart after an infarct that triggers a repair response from the bone marrow.

Related clinical research under way in China also uses adult stem cells, but they come directly from the patient, and no universal donor is used as in the Hopkins study.

It remains unclear from earlier animal studies how or why the adult stem cells develop into new and healthy heart tissue, or exactly how long their healing effects last.

Adult stem cells are being used because they are readily available from the bone marrow, where they are plentiful. A special kind of bone marrow stem cell, called a mesenchymal stem cell, was separated from other kinds for use in this study. While their precise biological action is not known, mesenchymal bone marrrow stem cells are known to give rise to a variety of cell types, including bone, cartilage, fat, and other kinds of connective tissue cells such as those in tendons, as well as muscle, such as the heart. A stem cell is a special type of body cell that gives rise to other types of specialized cells.

"Using mesenchymal stem cells also avoids potential problems with immunosuppression, in which every human's immune system might attack stem cells from sources other than itself," notes Hare. "Because they remain in an early stage of development, mesenchymal stem cells do not trigger an immune response, unlike what would happen if more developed stem cells were used.

"While the bone marrow adult stem cells do not have the same potential to develop into different organ tissues as do embryonic stem cells, the use of adult stem cells in this study shows their tremendous potential in developing effective therapies for heart disease, and avoids the controversy surrounding destruction of embryos to obtain the embryonic variety," he adds.

"Among its many benefits are that adult stem cells are readily available from a number of donors, and grow in large quantities in the lab. In our experiment, the treatment regimen is relatively simple, requiring only injection."

Heart Repair Gets New Muscle

Fri, 18 Mar 2005 17:30:38 PST

( from http://www.rxpgnews.com ) When you think of the cell as the fundamental unit of life, its not surprising that some organs deal with injury better than others. A flesh wound or muscle tear might hurt, but, assuming you are otherwise healthy, both will heal. The prognosis for a heart attack, on the other hand, is not so clear-cut. What accounts for the difference?

Skin cells reproduce regularly to replace dead cells, and simply increase production in the event of injury. Skeletal muscles recruit new muscle cells from a type of precursor cell within the muscle, called satellite cells, to repair a tear. Cardiac cells (cardiomyocytes), it has long been thought, appear to lack this capacity for self-renewal and repair, impeding the chances of a full recovery. Thats why therapies derived from stem cellswhich retain a unique ability to morph into any of the bodys 200-plus cell typeshold such promise. But stem cells are a hot-button issue in the United States, complicating efforts to explore this promise.

Recent evidence suggests that the heart might harbor stem cells after all and that such cells can be transformed into cardiomyocytes. In a new study, Neal Epstein and colleagues report that cells isolated from the skeletal muscle of adult mice can turn into beating cardiomyocytes in a test tube within days of isolationand without the addition of gene-altering drugs or special cardiac factors. When freshly isolated cells (called skeletal precursors of cardiomyocytes, or Spoc cells) are injected into the tail veins of mice with heart damage, they migrate to the damaged tissue and differentiate into cardiac muscle cells.

What distinguishes a cardiomyocyte from a skeletal muscle cell? Specialized cells produce unique proteins, allowing scientists to use those proteins as identifying markers. The so-called Spoc cells do not express any of the usual markers associated with either skeletal muscle satellite cells or partially differentiated skeletal muscle cells. By day 7 in culture, Spoc cells have undergone several rounds of cell division and have begun to express a (mostly) cardiac-specific protein, and have formed clusters of cardiac precursor cells, some of which beat. These precursors in turn express other cardiac-specific proteins.

Epstein and colleagues further divided Spoc-derived precursor cells into two groups based on whether or not they expressed another protein marker (Sca-1, a common marker found on blood stem cells). About 80% of cells without this protein differentiated into immature beating cells after proliferating for seven to ten days. They remained in an immature state (round and loosely attached) for over two months in culture, but differentiated into mature beating heart cells (elongated and adherent) when mixed with Sca-1 cells. The authors use video microscopy to track the cells progression to beating cells, complete with contraction-generating thick myosin filaments that are nearly identical to those seen in developing cardiomyocytes. Epstein and colleagues also demonstrate that the Spoc cells are distinct from stem cells cultured out of bone marrow, heart, or fat tissuesources of beating cells in other studies. The authors also injected these Spoc cells into mice with acute heart lesions to test the cells ability to integrate into the damaged tissue. Many cells successfully migrated to and engrafted into the site of injury; some of these cells developed into cardiomyocytes. The cells showed a similar, though less robust, response to an older heart injury.

Epstein and colleagues argue that Spoc cells are more likely to be precursors to cardiomyocytes than to be some other type of skeletal muscle stem cell. This is based on an absence of protein markers for skeletal muscle or skeletal satellite cells in Spoc cells, as well as the fact that Spoc-derived cells display spontaneous rhythmic beating and express cardiac markers, whether they are grown in a test tube or have migrated to injured hearts in study mice. The authors cant say why skeletal muscle would harbor cardiac stem cells or why so few of these cells pitch in to repair a cardiac injury. But for now, the Spoc cells provide a valuable tool for studying heart cell differentiation. And with time, they might prove an important resource for developing cell-based therapies for heart disease. See also the Primer Alchemy and the New Age of Cardiac Muscle Cell Biology (DOI: 10.1371/journal.pbio.0030131).

Signal-joint TRECs might predict success of stem cell transplant

Fri, 25 Feb 2005 18:32:38 PST

( from http://www.rxpgnews.com ) Measuring the quantity of a certain type of immune cell DNA in the blood could help physicians predict whether a bone marrow stem cell transplant will successfully restore a population of infection-fighting cells called T lymphocytes in a child.

This finding could help physicians predict whether children receiving such a transplant will experience either failure or significant delay in the reconstitution of the T cell population. Moreover, if the transplant is successful, T cells arising from donated stem cells will be available to launch attacks on the patients cancer cellsthe so-called graft-versus-tumor response. This will further improve the patients outcome following initial therapy (chemotherapy, irradiation and surgery).

Physicians sometimes treat patients with stem cell transplants as part of therapy for a variety of diseases such as leukemia or sickle cell disease. In these cases physicians eliminate the patients own stem cells that produce cancerous white cells or faulty red cells and replace them with healthy stem cells from donors. If the transplants succeed, the donated stem cells repopulate the blood with healthy red and white cells.

The St. Jude team showed that the more copies of tiny rings of DNA called signal-joint TRECs (sjTRECs) there are in a childs blood, the more likely it is that the patients thymus gland can act as an efficient factory where stem cells become T cells. The thymus is an immune system organ behind the breastbone that processes immature precursor immune cells into specialized T cells.

T lymphocytes are specialized immune cells carrying proteins called receptors on their surface. The target that a T cell recognizes and attacks depends on the makeup of its receptor, which is constructed of protein building blocks. Each protein building block is coded by a specific gene. sjTRECs form during a mix-and-match rearrangement of these genes into any one of countless combinations. The rings represent sections of DNA cut out of chromosomes during the mixing and matching of genes that are chosen to build a particular receptor. Each T cell uses the resulting combination of genes to make a receptor that lets the cell recognize a specific target. When stimulated to multiply, each of those cells produce an army of immune cells against their designated target.

Specific infectious organisms or other foreign substances stimulate T cells to divide and multiply in order to form an attacking army. However, the sjTRECs dont multiply when the original T cells divide and multiply. Instead, the more T cells that are produced in the blood as the parent cells containing sjTRECs divide and produce daughter cells, the more the sjTRECs in those original T cells get diluted within the growing army of these immune cells. This proves that high levels of sjTREC in blood means that a large number of stem cells have been converted to parent T cellseach of which targets a specific foreign substance, according to Rupert Handgretinger, M.D., Ph.D., director of Stem Cell Transplantation at St. Jude and co-director of the Transplantation and Gene Therapy Program.

sjTRECs appear only after the gene shuffling has successfully occurred in the parent cell, Handgretinger said. So if we extract large numbers of sjTRECs from T cells in the blood of a patient about to undergo a stem cell transplant, thats a good sign. It means the patients thymus is a good T-cell factory.

Handgretinger is the senior author of the Blood report.

The St. Jude team tested levels of sjTREC in the blood of 77 healthy donors who provided stem cells to their siblings. The researchers also tested 244 samples from 26 of the recipients themselves. The recipients had been treated for either white cell cancers (e.g., acute lymphoblastic leukemia) or red cell diseases (e.g., sickle cell disease).

Because blood from the normal, healthy donors contained 1,200 to 155,000 sjTREC copies per milliliter of blood, the investigators chose 1,200 as the lowest end of the normal range for sjTRECs.
The team found that transplant recipients who had more than 1,200 copies of sjTREC in each milliliter of their blood before transplantation were more likely than patients with fewer copies to experience successful reconstitutions of their T cell populations. In patients with fewer than 1,200 copies per milliliter, the transplantation was likely either to fail or be significantly slow in reconstructing the T cell population.

This is the first demonstration that high levels of sjTREC in a potential stem cell recipient can predict that their thymus will successfully reconstitute their T cell population using donated stem cells, said Xiaohua Chen, Ph.D., first author of the Blood article. This kind of information should help physicians improve their ability to manage individual patients by predicting how they will respond to stem cell transplants.

oct-4 gene discovered in adult stem cells

Fri, 18 Feb 2005 16:17:38 PST

( from http://www.rxpgnews.com ) Michigan State University researchers have found that a certain gene, expressed within a human adult stem cell, could hold the key to not only offering new hope to cancer patients, but also to answering the question of how cancer originates.

The discovery that the gene known as oct-4 is expressed in normal adult stem cells, by MSUs James Trosko and colleagues, is detailed in the February issue of Carcinogenesis, one of the worlds top cancer-research journals.

It was already known that the oct-4 gene was located in embryonic stem cells as well as tumor cells, but researchers were uncertain whether it was expressed in adult stem cells.

The MSU researchers, using methods pioneered in their laboratory, were able to test adult stem cells for the expression of the oct-4 gene and found that it was expressed in some adult stem cells.

If oct-4 is a biomarker for adult stem cells that gives rise to cancer cells, Trosko said, then learning how to turn off the expression of the oct-4 gene in cancer cells or even in pre-malignant cells should have tremendous implications for both prevention and treatment of cancer.

In particular, he said, the use of oct-4 as a screening marker to identify new chemoprevention dietary agents and chemotherapeutic drugs could be extremely helpful in fighting cancer.

This is especially significant in light of recent findings that, within the billions of cells of a tumor, there exists a few cancer stem cells that seem to be the cells that are resistant to cancer therapy, Trosko said. In other words, current practices to treat cancers have been directed at the wrong tumor cells.

The oct-4 gene is a regulatory gene, one whose job is to control the expression of other genes.

When it comes to the question of where cancer cells originate, there are two prevailing theories: Either a single stem cell is the target for the process to begin, or any highly specialized, or differentiated, cell can be the target cell.

The problem with the second theory, said Trosko, is that for a differentiated cell one that is already on its way to becoming a kidney cell or breast cell or any other specialized type of cell to become cancerous, it must first revert back to stem-cell stage.

In other words, he said, it has to turn back time.

So what we found is that the human adult stem cell in which the oct-4 gene was expressed was the target cell for the carcinogenic process to begin. In cells in which it was not expressed, they could not convert back to the adult stem cell stage and then go cancerous.

Trosko added that there are many benefits to working with adult stem cells, as opposed to embryonic stem cells.

In particular, were able to bypass the ethical, religious, legal and political issues that are raised when we talk about embryonic stem cells, he said. Were able to get the adult stem cells from consenting adults.

Hemophilia reversed in mice with stem cells

Wed, 16 Feb 2005 15:29:38 PST

( from http://www.rxpgnews.com ) University of North Carolina at Chapel Hill researchers have made a discovery that may have implications for the treatment of liver-based genetic defects such as hemophilia A and B in humans. Mouse embryonic stem cells treated in culture with a growth factor and then injected into the liver reverse a form of hemophilia in mice analogous to hemophilia B in humans, the new study shows. A report of the study appears in the journal Proceedings of the National Academy of Sciences today (Feb. 15).

The genetically altered mice lack the clotting substance factor IX, which in humans results in the hereditary bleeding disorder known as hemophilia B. This disease, much less common than hemophilia A, affects roughly one of every 35,000 people, primarily males.

Although embryonic stem, or ES, cells can differentiate into most cell types in the body, numerous problems have arisen in translating their potential into therapeutic strategies, the UNC School of Medicine study authors reported.

These problems include poor engraftment, limited function, rejection of engrafted cells by the immune system and teratomas, tumors involving a mixture of tissue not normally found at that site.

The new study used a line of mouse ES cells developed in the laboratory of senior co-author Dr. Oliver Smithies, Excellence professor of pathology and laboratory medicine at UNC.

A member of the National Academy of Sciences, Smithies has won many honors for gene targeting, a technique he pioneered. This technique allows for the development of mice with specific genetic mutations that mimic human illnesses such as hemophilia. In 2001, Smithies received the Albert Lasker Award for Basic Medical Research, often called "Americas Nobel."

In the study, ES cells were treated with fibroblast growth factor for seven days prior to injection. As expected, this resulted in ES cells differentiating into early endoderm like precursors, which the researchers named "putative endoderm precursors," or PEPs. Endoderm refers to the inner layer of early embryonic cells that develops into the digestive and respiratory systems.

"Not only do ES cells differentiate into PEPs, they also engraft, persist, differentiate further and then function following injection, resulting in the persistent production of factor IX protein that can only come from a hepatocyte (liver cell) and hemophilia reversal," said study lead author Dr. Jeffrey H. Fair, associate professor of surgery and division chief of abdominal transplant surgery.

Moreover, he said, the PEP cells robustly engraft within the liver and were not recognized by the immune system as foreign.

"Within a few weeks, PEPs became hepatocytes," Fair added. "They went from something that is a very early grandparent of the hepatocyte to becoming hepatocytes. After 115 days, nearly four months after injection, mice still produced factor IX without immune suppression. This occurred even in mice that were a complete immunologic tissue mismatch to the PEPs. In addition, the incidence of teratomas was low."

The researchers believe this study demonstrates the power of multidisciplinary collaboration, said co-lead author Dr. Bruce A. Cairns, assistant professor of surgery and director of research in the N.C. Jaycee Burn Center. "This approach may not only be beneficial, but required in order to solve complex problems such as these in medicine."

Although a number of questions need to be answered, this work has great potential for future applications, not only as a novel therapeutic possibility for hemophilia but also for other genetic or acquired diseases of the liver, said senior co-author Dr. Jeffery A. Frelinger, Kenan professor and chairman of microbiology and immunology.

"The data published in this study shows that embryonic stem cells partially differentiated, are able to remain in the liver and be functional without apparent immunological rejection. This transforms them into possible candidates for cellular transplantation into the liver."

Along with Fair, Cairns, Smithies and Frelinger, co-authors from the department of surgery are Dr. Michael A. LaPaglia, Dr. Montserrat Caballero, Dr. Anthony A. Meyer (chairman) and W. Andrew Pleasant. From the department of pathology and laboratory medicine are Drs. Seigo Hatada and Hyung-suk Kim. From the College of Arts and Sciences department of biology are Drs. Tong Gui and Darrel W. Stafford; and from the department of genetics, Dr. Larysa Pevny.

The research was supported by grants from the National Institutes of Health and the N.C. Jaycee Burn Center.

Specialized stem cells located in heart of newborns

Thu, 10 Feb 2005 18:01:38 PST

( from http://www.rxpgnews.com ) The first evidence of cardiac progenitor cells rare, specialized stem cells located in the newborn heart of rats, mice and humans has been shown by researchers at the University of California, San Diego (UCSD) School of Medicine. The cells are capable of differentiation into fully mature heart tissue.

Called isl1+ cells, these cardiac progenitor cells are stem cells that have been programmed to form heart muscle during fetal growth. Until this new discovery, the cells were thought to be absent after birth. However, the UCSD team discovered a small number of the specialized stem cells remained embedded in a region of the newborn heart called the atrium. They also determined that the cells could be expanded into millions of progenitor cells by growing them on a layer of neighboring heart cells called fibroblasts.

Published in the February 10, 2005 issue of the journal Nature, the research identified the isl1+ progenitor cells in the tissue of newborn rats and mice, and then in heart tissue taken from five newborn human babies undergoing surgery for congenital heart defects.

Study author Sylvia Evans, Ph.D., a member of the UCSD Institute of Molecular Medicine (IMM) and professor of pharmacology, and co-first author Alessandra Moretti, Ph.D., IMM member, explained that the cells are programmed to become spontaneously beating cardiac muscle cells simply by exposure to other neighboring heart cells.

And, since these rare cardiac progenitor cells are found in regions of the atrium that are normally discarded during routine cardiac surgery, the discovery raises the possibility that an individual could receive their own cardiac stem cells to correct a wide spectrum of pediatric cardiac diseases, according to co-first authors Moretti and Karl-Ludwig Laugwitz, M.D., a Heisenberg-Scholar of the German Research Foundation.

"Conceptually, these cells could provide a cell-therapy based approach to pediatric cardiac disease, which is new for cardiology," said the study's senior author, Kenneth Chien, M.D., Ph.D., director of the UCSD Institute of Molecular Medicine. "Traditionally, pediatric cardiologists and cardiac surgeons have relied on mechanical devices, human and synthetic tissue grafts, and artificial and animal derived valves to surgically repair heart defects. While progenitor cells won't grow a whole new heart, our research has shown that they can spontaneously become cells from specific parts of the heart by simple co-exposure to other heart cells, which could augment existing surgical procedures. If the cells maintain pacemaker function when placed in the intact heart, they might serve as biological pacemakers for infants born with heart block, which could also be valuable."

After the isl1+ cells were found in newborn rats, the UCSD team used sophisticated genetic methods to tag the progenitor cells in living embryonic tissue and in the newborn heart of mice. With these techniques, they were able to show that the isl1+ progenitor cells were spontaneously able to form cardiac muscle tissue.

"Furthermore, the cardiac muscle cells formed were totally mature and had the complete array of function that one would expect in completely differentiated heart tissue," said the study's co-first author Jason Lam, Ph.D. candidate in the IMM. The cells exhibited contractility, pumping ability, the correct electrical physiology and normal heart structure. In addition, the progenitor cells coupled with neighboring cardiac muscle cells with resulting normal electrical heart beats.

"Another important discovery was the ability to expand the few cells found in a newborn heart, into millions of cells in lab culture dishes," Laugwitz said. "This implies that the isl1+ cells potentially could be harvested from an individual's heart tissue, multiplied in a laboratory setting, then re-implanted into the patient. Furthermore, the developmental lineage marker which identifies undifferentiated cardiogenic precursors suggests the feasibility of isolating isl1+ cardiac progenitors from mouse and human embryonic stem cell systems during cardiogenesis."

"We think that these cells normally play an important role in the remodeling of the heart after birth, when the newborn heart no longer relies upon the mother's circulation and oxygenation," Chien said. "We believe the isl1+ progenitor cells are left over from fetal development so that they can insure the closure of any existing small heart defects and the formation of a completely mature heart in newborns."

The UCSD team noted in the Nature paper that the next research steps with the isl1+ cells will be cellular transplantation in living animals to study their role in endogenous repair after cardiac injury.

Human Neural Stem Cells Transplantation to Help Children with Batten Disease,under trial

Wed, 02 Feb 2005 10:23:38 PST

( from http://www.rxpgnews.com ) Batten disease is a rare, fatal genetic disorder that affects the central nervous system of children.If approved by the FDA, this would mark the first-ever FDA-approved clinical trial to use a purified composition of human neural stem cells as the potential therapeutic agent.

StemCells Inc.,today announced that it has been in communication with the U.S. Food and Drug Administration (FDA) regarding the filing of the Company's first Investigational New Drug (IND)application.The filing, announced on January 4,2005,is for a Phase I clinical trial of StemCells' proprietary neural cell therapy product-HuCNS-in Batten disease.

This is truly a significant milestone, not only for StemCells,Inc.,but also for all scientists who have been seeking to evaluate possible therapies for neural and neurodegenerative diseases, said Martin McGlynn, chief executive officer of StemCells, Inc.

He added,Our pre-clinical research has shown great promise and this filing is an essential step in discovering how to translate those pre-clinical results into treatment of human victims of terrible disorders like Batten disease and other neurodegenerative lysosomal storage diseases.It is only a first step, thoughthis is a Phase I,or safety, trial, from which we hope to learn about the behavior of the cells when they are transplanted into a human recipient.There will be many other steps to take before we arrive.But it is our hope that transplantation of human neural stem cells could prove to be a platform technology for a wide range of conditions for which there is now no reliable and effective treatment.

We are looking forward to working with the scientists at StemCells in this historic clinical trial, said Dr. Huhn, at the Stanford University School of Medicine. We are exploring new territory, which dictates that we proceed with due caution.I believe, however, that our path has been determined by rigorous research and a well-designed protocol.Physicians have been essentially helpless to assist children suffering from Battens, and all of us involved in this trial are hoping it will lead to a future in which we will have an efficient treatment, or even a cure.As a pediatric neurosurgeon, I am particularly excited about this avenue of research.

The proposed Phase I trial is designed to investigate the safety of HuCNS-SC in the treatment of infantile and late-infantile neuronal ceroid lipofuscinosis (NCL),the most severe forms of a group of disorders commonly referred to as Batten disease.

The trial will be an open label study of two dose levels involving three subjects in each of two cohorts.The primary objective of the trial will be to measure the safety of HuCNS-SC, however, the trial will also evaluate HuCNS-SCs ability to affect the progression of the disease.The patient/subject evaluation will be up to one year post HuCNS-SC transplantation. Candidates from anywhere in the world will be referred by their primary physicians to the Co-principal Investigators at LPCH/SUMC. Potential patients will be tested for eligibility and then evaluated for baseline disease status prior to transplantation.

Batten disease is named after the British pediatrician who first described the juvenile form of NCL in 1903. It is also known as Spielmeyer-Vogt-Sjogren-Batten disease.The name is now commonly used to encompass all three forms of NCL.

The forms of NCL are classified by age of onset (infantile, late infantile and juvenile) but are more precisely classifiable in terms of the specific enzyme causing the disease.They all have the same basic causelack of a lysosomal enzymeand similar progression and outcome, but are all genetically different.Children with Batten disease suffer seizures, progressive loss of motor skills, sight and mental capacity, eventually becoming blind, bedridden and unable to communicate.Today,Batten disease is always fatal.

In two sub-types of the NCLs infantile and late infantile or, more technically,CLN1 and CLN2normally secreted housekeeping lysosomal enzymes are either defective or missing altogether, as a result of gene mutations.Lack of either enzyme causes a buildup of lipofuscin (aggregates of lipids and proteins) primarily in the brain and leads to neuronal cell loss.

These lysosomal storage disorders are brought on by inherited genetic mutations in CLN1 gene,which codes for palmitoyl-protein thioesterase 1(PPT1) and in the CLN2 gene, which codes for tripeptidyl peptidase I (TPP-I).

The consequence of these mutations is the accumulation of lipofuscin-like fluorescent inclusions in various cell types that eventually lead to cell degeneration.

In the proposed clinical trial, HuCNS-SC will be transplanted in the CLN1 and CLN2 patients in part to determine if the transplanted cells secrete the missing lysosomal enzymes in the brains of affected individuals.

HuCNS-SC have been shown to produce both PPT1 and TPP-I enzymes, providing a scientific justification for enzyme replacement and cellular rescue in this indication.In preclinical models of PPT1 deficiency, the corresponding enzyme activity increases with time after transplantation.

Genetic selection of mouse male germline stem cells in vitro: Offspring from single stem cells

Tue, 04 Jan 2005 18:55:38 PST

( from http://www.rxpgnews.com ) Since the classic work of Brinster and colleagues demonstrating that spermatogonial stem cells could be transplanted within seminiferous tubules, where they proliferate and undergo sperm development, it has been hoped that the system could be adapted for germline modifications. This, however, entails a number of challenging technical steps such as the propagation of cultures of spermatogonial stem cells, introduction of genetic modifications, and selection of the modified stem cells.

Mito Kanatsu-Shinohara and colleagues met the first challenge with a cocktail of growth factors, published previously in Biology of Reproduction (Kanatsu-Shinohara M, Ogonuki N, Inoue K, Miki H, Ogura A, Toyokuni S, Shinohara T. Long-term proliferation in culture and germline transmission of mouse male germline stem cells. Biol Reprod 2003; 69: 612-616.); they refer to the spermatogonial stem cells established in this way as germline stem cells (GS). In the January 2005 issue of Biology of Reproduction, this group reports another very significant step forward. They transfected the GS cells with a construct designed to express both enhanced green fluorescent protein (EGFP) and neo to allow drug selection of modified cells. The colonies derived from single modified and selected GS cells were expanded and then injected into seminiferous tubules of germ cell-free mutant mice. After mating, these mice produced offspring that not only expressed the introduced EGFP construct but also passed it on to their offspring and subsequent generations. This groundbreaking work sets the stage for further germline modifications that will be important for a wide range of experimental analyses. Further, this work will have profound implications if the technologies can be applied to the clinic.