Cornelia Laule1, 2, Vlady Pavlova1, David K.B. Li2, Guojun Zhao2, Piotr Kozlowski2, Anthony L. Traboulsee, G.R. W. Moore1
1Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada; 2Radiology, University of British Columbia, Vancouver, BC, Canada
Given the potential prognostic importance of non-lesional white matter abnormalities in MS, histological studies are warranted to elucidate the pathology underlying the MRI-defined phenomena of diffusely abnormal white matter (DAWM). Post-mortem MS brain was examined with multi-echo T2 relaxation and histological staining. DAWM showed substantial decreases in myelin water fraction (-30%) and myelin phospholipids (-29%, -24%), with much less involvement of the myelin proteins (-11% to -5%). Lesions demonstrated more severe abnormalities than DAWM, with decreases in both myelin lipids and proteins. Our findings are consistent with a primary lipid abnormality that antedates myelin protein loss in DAWM.