Dynamics and heterogeneity of brain damage in multiple sclerosis

Area of Science:

• Neuroimmunology
• Computational Biology
• Clinical Neurology

Background:

• Multiple Sclerosis (MS) is an autoimmune disease causing central nervous system (CNS) damage through inflammation and degeneration.
• The interaction and evolution of these pathogenic mechanisms leading to MS heterogeneity remain poorly understood.

Purpose of the Study:

• To test the hypothesis that disease course variability in MS is driven by the interplay of autoimmune attack, chronic inflammation, neuroaxonal degeneration, and remyelination.
• To explain clinical heterogeneity in MS by proposing differential severity and timing of these pathogenic processes.

Main Methods:

• Developed and validated a mathematical model using longitudinal Expanded Disability Status Scale (EDSS) data from two patient cohorts (retrospective and prospective).
• Employed unsupervised clustering analysis to group EDSS time series and reduce clinical heterogeneity.
• Constrained the model with experimental data, including brain volume time series in the prospective cohort.

Main Results:

• The mathematical model, with parameter adjustments within biological ranges, successfully reproduced diverse MS disease courses, supporting the dynamic CNS damage hypothesis.
• Irreversible axon degeneration in progressive MS is linked to high myelinated axon degeneration rates and low remyelination capacity.
• Relapsing MS exhibits greater resilience than progressive MS due to lower axon degeneration rates and faster remyelination.

Conclusions:

• MS subtypes share a common pathogenesis, with clinical variability arising from distinct dynamics of CNS damage and repair.
• The findings suggest MS can be viewed as a single disease with diverse clinical outcomes driven by specific pathogenic process dynamics.
• Results offer insights for designing stage-specific therapeutic interventions for MS.