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Updated: Jun 12, 2026
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Density distribution of myelin fragments isolated from control and multiple sclerosis brains
Abstract:
Myelin from subcortical normal-appearing white matter of control and multiple sclerosis (MS) brains was isolated and subsequently subfractionated on discontinuous sucrose gradients. Three following myelin subfractions were obtained: light myelin (buoyant density ? 0.625 M), medium myelin (0.625 M > buoyant density ? 0.7 M), and heavy myelin (buoyant density > 0.7 M). The yield of total myelin (the sum of all three subfractions) recovered from MS specimens was about 30% lower than that from the white matter of the control brains. Furthermore, MS myelin was deficient in the light subfraction and was enriched in the heavy subfraction. No abnormality in lipid composition of MS subfractions was observed. On the other hand, myelin particles isolated from the MS tissue were depleted in basic protein. The results are interpreted as an evidence for a rather diffused pathological process in MS white matter.
Insights
Multiple sclerosis (MS) brains show reduced myelin yield and altered myelin composition, with less light myelin and more heavy myelin. MS myelin also lacks basic protein, indicating a widespread pathological process.
Area of Science:
- Neuroscience
- Biochemistry
- Pathology
Background:
- Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system.
- Understanding myelin alterations in normal-appearing white matter is crucial for MS research.
Purpose of the Study:
- To investigate the biochemical and compositional changes in myelin from subcortical normal-appearing white matter in MS.
- To characterize myelin subfractions and their protein and lipid content in MS versus control brains.
Main Methods:
- Myelin was isolated from subcortical white matter of control and MS brains.
- Myelin was subfractionated using discontinuous sucrose gradients into light, medium, and heavy fractions.
- Lipid composition and basic protein content of myelin subfractions were analyzed.
Main Results:
- Total myelin yield was approximately 30% lower in MS brains compared to controls.
- MS myelin showed a deficiency in the light subfraction and enrichment in the heavy subfraction.
- While lipid composition remained normal, MS myelin was depleted in basic protein.
Conclusions:
- The observed myelin alterations suggest a diffuse pathological process in the white matter of MS patients.
- Changes in myelin subfractions and basic protein content indicate myelin instability or degradation in MS.
- These findings contribute to understanding the early pathological changes in MS.
