42 - Brain microvasculature in multiple sclerosis

Summary

Introduction

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disorder of the central nervous system (CNS) that is the most common cause of acquired neurological dysfunction in young adults. The clinical manifestations and progression of MS vary widely amongst patients but are characterized by focal involvement of the optic nerves, spinal cord and brain that remit to a varying extent and recur over a period of years. Although the etiology remains unknown, there is strong circumstantial evidence to support the conclusion that it is mediated by an autoimmune attack directed against CNS myelin (Hafler and Weiner, 1995). A substantial genetic component to the disease process has been implicated by the observations that the risk for first degree relatives is increased over the general population, but environmental factors have also been shown to play a role (Ebers, et al., 1995). Active lesions are characterized by perivascular cuffs of lymphocytes and macrophages centered on post-capillary venules, particularly in the periventricular white matter, the optic nerve and tract, the corpus callosum and brainstem. Older lesions are immunologically silent in terms of inflammation and comprise large astroglial scars and demyelinated axons (Raine, 1990). Lesions are rarely noted beyond the root entry zones of the cranial and spinal nerves.