Glymphatic System May Mediate the Relation Between Choroid Plexus and Brain Damage in Multiple Sclerosis

Area of Science:

• Neuroimmunology
• Neuroimaging
• Cerebrospinal Fluid Dynamics

Background:

• The choroid plexus (CP) regulates brain immunity and cerebrospinal fluid (CSF) production, crucial for the glymphatic system.
• In multiple sclerosis (MS), CP enlargement and glymphatic dysfunction are observed but their relationship to brain damage is unclear.

Purpose of the Study:

• To investigate if glymphatic system dysfunction mediates the association between CP enlargement and brain damage in MS patients.
• To explore the link between CP volume, glymphatic function, and brain injury markers in MS.

Main Methods:

• MRI scans (FLAIR, T1-weighted, DWI, SWI) were acquired from 146 MS patients and 72 healthy controls (HC).
• Glymphatic function was assessed using the diffusion along the perivascular space (DTI-ALPS) index.
• Automated measurement of CP volume was performed.

Main Results:

• MS patients exhibited larger CP and white matter (WM) lesion volumes, and reduced DTI-ALPS index and brain volumes compared to HC.
• In MS, increased CP volume correlated with lower DTI-ALPS index and higher WM lesion volumes.
• The DTI-ALPS index partially mediated the association between normalized CP volume and WM lesion volumes, as well as normalized brain volumes.

Conclusions:

• Enlarged normalized CP volume in MS may contribute to brain damage.
• This contribution might occur through promoting a chronic proinflammatory state and mediating glymphatic system dysfunction.