Pathogenesis of tissue injury in MS lesions

Multiple sclerosis (MS) is an inflammatory disease of the central nervous s ystem. The primary pathological target in multiple sclerosis is myelin. Mos t MS patients follow a relapsing-remitting (RR-MS) course for 10 to 15 year s that transforms into a chronic or secondary progressive disease (SP-MS). This review summarizes studies from our laboratory that implicate activated microglia and astrocytes in early stages of myelin destruction in MS brain . In addition, we review evidence that indicates that axonal transection is a major pathological process in multiple sclerosis. Our data support the h ypothesis that neurological disability in RR-MS is due to inflammatory demy elination while axonal loss plays a significant role in the irreversible ne urological decline in SP-MS. Further elucidation of the pathological target s and pathological mechanisms of tissue destruction in MS brain will help i dentify new therapeutics. (C) 1999 Elsevier Science B.V. All rights reserve d.