Interferon Does Not Affect Duration Of "Black Hole" Lesions In Multiple Sclerosis
Sep 13, 2005 - 1:56:38 PM
Although treatment with interferon appears to reduce the formation of new areas of damage in the brains of patients with multiple sclerosis (MS), including lesions that appear as highly contrasted images, called black holes, on magnetic resonance imaging (MRI), treatment does not appear to affect the duration of these damaged regions, according to a new study posted online today by the Archives of Neurology, one of the JAMA/Archives journals. The study will be published in the November print edition of the journal.
Previous studies have shown that treatment with interferon beta-1b, a chemical that has activity on the immune system, reduces the formation of lesions visible to MRI, according to background information in the article. Chronic, persisting black holes reflect areas of irreversible nerve fiber loss and permanent damage. Black holes of shorter duration are believed to reflect the presence of short-term swelling. Shortening the duration of black holes, the authors suggest, may prevent the formation of permanent detrimental lesions, ultimately exerting a neuro-protective effect.
Francesca Bagnato, M.D., of the National Institute of Neurological Disorders and Stroke, Bethesda, Md., and colleagues analyzed MRIs for both the formation and duration of black holes for six patients with relapsing-remitting type MS. Monthly MRIs were obtained for 36 months before the treatment was initiated (natural history phase) and for 36 months during treatment with interferon (therapy phase).
The researchers found that the number of new black holes increased during both the treatment and natural history phases for all patients, but the accumulation of new black holes was substantially lower for patients during the treatment phase. The duration of new black holes arising during the treatment phase was not shorter than the duration of black holes arising during the natural history phase, however.
"The sample size is small, but the length of the longitudinal followup (i.e., 72 months) represents a robust and valid data set for describing the course of MS during both the NHPs [natural history phase] and TPs [therapy phase]," the authors note. "We demonstrate that new BHs [black holes] may significantly accumulate over time even when IFNβ-1b [interferon beta-1b] is administered. However, repeated administration of the drug did significantly decrease the rate of BH formation, thus protecting the brain tissue from accumulating degenerative lesions."
"One can postulate that although IFNβ-1b may reduce the frequency of BHs, after the lesion occurs, the drug is not changing the pathological process," the authors write. They suggest larger studies over longer periods might reduce difficulties in interpretation encountered in this study, allowing a better assessment of whether the analysis used might be useful in establishing the proper role of neuroprotective drugs of the central nervous system in the treatment of patients with MS.
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