Distinct patterns of multiple sclerosis pathology indicates heterogeneity on pathogenesis

Area of Science:

• Neuroscience
• Immunology
• Pathology

Background:

• Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system.
• MS pathology is characterized by demyelinated plaques and glial scarring.
• Existing understanding suggests potential heterogeneity in myelin destruction pathogenesis.

Purpose of the Study:

• To present a novel classification scheme for lesional activity in MS.
• To categorize demyelination patterns based on the molecular composition of myelin degradation products.
• To explore the heterogeneous nature of myelin destruction in MS.

Main Methods:

• Analysis of demyelination patterns, oligodendroglia pathology, and tissue reactions.
• Classification of lesional activity using molecular composition of myelin degradation products in macrophages.
• Review of experimental models of inflammatory demyelination.

Main Results:

• Distinguished diverse demyelination patterns: relative oligodendrocyte preservation, concomitant oligodendrocyte destruction, primary myelinating cell destruction with secondary demyelination.
• Identified cases of primary selective demyelination followed by secondary oligodendrocyte loss.
• Observed severe lesions with loss of myelin, oligodendrocytes, axons, and astrocytes.

Conclusions:

• The heterogeneity of plaque pathology in MS is significant.
• Different immunological pathways can lead to demyelinated plaques with diverse structural features.
• Demyelinated plaques in MS may represent a common pathological endpoint of various immunological myelin destruction mechanisms.