The relation between inflammation and neurodegeneration in multiple sclerosis brains

Area of Science:

• Neurology
• Immunology
• Neuroscience

Background:

• Recent research suggests neurodegeneration in progressive multiple sclerosis (MS) might be independent of inflammation.
• Understanding the interplay between inflammation, neurodegeneration, and disease progression is crucial across all MS stages.

Purpose of the Study:

• To analyze the interdependence of inflammation, neurodegeneration, and disease progression in multiple sclerosis (MS).
• To investigate these relationships in various MS stages, focusing on progressive MS, lesional activity, and clinical course.

Main Methods:

• Detailed quantification of inflammatory cells (T-cells, B-cells, plasma cells) and axonal injury in 67 MS autopsies and 28 controls.
• Comparison across different disease stages (acute, relapsing, secondary progressive, primary progressive) and age-matched controls.

Main Results:

• Pronounced brain inflammation observed in all MS stages, including progressive forms.
• Plasma cell infiltrates persisted in secondary progressive multiple sclerosis (SPMS) and primary progressive multiple sclerosis (PPMS) even as T- and B-cell infiltrates declined.
• A significant association between inflammation and axonal injury was found in the overall MS population and specifically in progressive MS.
• In older, long-standing MS patients, inflammation and axonal injury levels approached those of controls, suggesting other pathologies may drive ongoing neurodegeneration.

Conclusions:

• A strong association exists between inflammation and neurodegeneration across all lesions and disease stages of multiple sclerosis (MS).
• The study indicates that MS disease processes might diminish in elderly patients with long-standing disease.
• While inflammation and neurodegeneration are linked, other pathologies may contribute to neurodegeneration in aged, long-term MS patients.