The following is a summary of “Influence of Cardiorespiratory Fitness and MRI Measures of Neuroinflammation on Hippocampal Volume in Multiple Sclerosis Patients,” published by Morozumi, et al.

This study aimed to examine whether or not improved cardiorespiratory fitness (CRF) mitigates the adverse effects of neuroinflammation on hippocampus volume in the leading multiple sclerosis (MS) clinical phenotypes. The hippocampus is an adult brain area characterized by adaptability and neurogenesis with critical clinical applications. Neuroinflammation and CRF may directly affect hippocampus integrity, altering the balance between processes that foster neurogenesis and neuroprotection.

A total of 81 people with MS (relapsing-remitting [RR] and 54 progressive [P]) and 47 age- and sex-matched health controls (HC) had structural MRIs of their brains taken and their maximum oxygen consumption (VO2 max), a proxy of CRF. Two volumes were measured to assess neuroinflammation: the T2-hyperintense lesion volume (T2-LV) in the white matter and the choroid plexus volume (CPV). Using linear regression analysis, researchers looked at the correlations between T2-LV, CPV, and CRF and normalized brain (NBV), gray matter (NGMV), thalamic (NTV), and hippocampus volumes. Hierarchical stepwise regression models were used to assess the relative importance of demographic, clinical, T2-LV, CPV, and VO2 max variables in explaining the volumes of interest.

Except for NGMV (P=0.105), increased T2-LV in MS was linked with reduced global and regional brain volumes (standardized- β from -0.706 to -0.356, P ≤ 0.009). In RRMS and PMS patients, higher CPV was only significantly linked with reduced NBV and NTV (standardized- β from -0.545 to -0.290, P ≤ 0.045). Only in individuals with RRMS did an increase in VO2 max correlate with increased normalized hippocampus volume (standardized-β =0.448, P =0.013). A considerable amount of hippocampus volume variance was explained by T2-LV in both RRMS (∆R2=0.124, P=0.043) and PMS patients (∆R2=0.095, P =0.028) and VO2max exclusively in RRMS (∆R2=0.153, P=0.014) using stepwise hierarchical regression models. A greater CRF may play a unique neuroprotective role for the hippocampus, especially in the early stages of MS, by exerting positive neurotrophic effects.