Dirty-appearing white matter in multiple sclerosis Preliminary observations of myelin phospholipid and axonal loss

• Published in: Journal of neurology Vol. 255; no. 11; pp. 1802 - 1811
• Main Authors: Moore, G. R. W., Laule, C., MacKay, A., Leung, E., Li, D. K. B., Zhao, G., Traboulsee, A. L., Paty, D. W.
• Format: Journal Article
• Language: English
• Published: Dordrecht D. Steinkopff-Verlag 01-11-2008; Springer; Springer Nature B.V
• Subjects: 2',3'-Cyclic-Nucleotide Phosphodiesterases; Aged; Astrocytes - pathology; Biological and medical sciences; Brain - pathology; Female; Glial Fibrillary Acidic Protein; Humans; Indoles; Male; Medical sciences; Medicine; Medicine & Public Health; Middle Aged; Multiple Sclerosis - pathology; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Myelin Proteins - metabolism; Nerve Degeneration - pathology; Neurology; Neurons - physiology; Neurons - ultrastructure; Neuroradiology; Neurosciences; Original Communication; Phospholipids - metabolism; normal-appearing white matter; magnetic resonance imaging; myelin water fraction; dirty-appearing white matter; multiple sclerosis; Nervous system diseases; Multiple sclerosis; Myelin; Central nervous system disease; Phospholipid; Nuclear magnetic resonance imaging; White matter; Inflammatory disease
• ISSN: 0340-5354; 1432-1459
• DOI: 10.1007/s00415-008-0002-z

“Dirty-appearing white matter” (DAWM) in multiple sclerosis (MS) is defined as a region(s) with ill-defined borders of intermediate signal intensity between that of normal-appearing white matter (NAWM) and that of plaque on T
2
-weighted and proton density imaging. To delineate the histopathology of DAWM, four formalin-fixed cerebral hemisphere slices of three MS patients with DAWM were scanned with T
2
- weighted and proton density sequences. The myelin water fraction (MWF) was obtained by expressing the short T
2
component as a fraction of the total T
2
distribution. Hemispheric sections were then stained with Luxol fast blue (LFB) for myelin phospholipids, for myelin basic protein (MBP) and 2’,3’-cyclic nucleotide 3’-phosphohydrolase (CNP) for myelin; Bielschowsky silver impregnation for axons; and for glial fibrillary acidic protein (GFAP) for astrocytes. Compared to NAWM, DAWM showed reduction in MWF, corresponding to a reduction of LFB staining. DAWM also showed reduced Bielschowsky staining. Quantitatively, the change in MWF in DAWM most consistently correlated with the change in LFB staining. The findings of this preliminary study suggest that DAWM is characterized by loss of myelin phospholipids, detected by the short T
2
component, and axonal reduction.