Axonal changes in chronic demyelinated cervical spinal cord plaques

Imaging and pathomorphological studies in multiple sclerosis suggest that a xonal injury and axonal loss are playing a crucial role in those with persi stent disability and long-standing disease. Although the existence of axona l injury in multiple sclerosis is proven, especially in the zone of active inflammation, the effect of chronic inflammation on the axons remains elusi ve, The aim of this study was to perform a quantitative morphometrical anal ysis, estimating axonal loss and evaluating axonal degenerative changes in cervical spinal cord samples of patients suffering from secondary progressi ve multiple sclerosis, Completely demyelinated plaques, normal appearing wh ite matter (NAWM) and control material from anatomically identical regions of the cord have been compared. Neurofilament immunostaining was used for i dentification of the axons, We observed a significant reduction of axonal d ensity (number of axons/mm(2)) in multiple sclerosis, both in the plaque an d in the NAWM compared with the control cases, Axons under similar to 3.3 m u m diameter seemed to be more affected. The intensity of the immunostainin g was significantly reduced in the plaque compared with either NAWM or cont rol. Our results on the cervical cord combined with other observations supp ort the concept of slow axonal degeneration rather than acute damage as a c ause of chronic disability in multiple sclerosis.