Vagus nerve stimulation enhances remyelination and decreases innate neuroinflammation in lysolecithin-induced demyelination.

BACKGROUND: Current treatments for Multiple Sclerosis (MS) poorly address chronic innate neuroinflammation nor do they offer effective remyelination. The vagus nerve has a strong regulatory role in inflammation and Vagus Nerve Stimulation (VNS) has potential to affect both neuroinflammation and remyelination in MS. OBJECTIVE: This study investigated the effects of VNS on demyelination and innate neuroinflammation in a validated MS rodent model. METHODS: Lysolecithin (LPC) was injected in the corpus callosum (CC) of 46 Lewis rats, inducing a demyelinated lesion. 33/46 rats received continuously-cycled VNS (cVNS) or one-minute per day VNS (1minVNS) or sham VNS from 2 days before LPC-injection until perfusion at 3 days post-injection (dpi) (corresponding with a demyelinated lesion with peak inflammation). 13/46 rats received cVNS or sham from 2 days before LPC-injection until perfusion at 11 dpi (corresponding with a partial remyelinated lesion). Immunohistochemistry and proteomics analyses were performed to investigate the extend of demyelination and inflammation. RESULTS: Immunohistochemistry showed that cVNS significantly reduced microglial and astrocytic activation in the lesion and lesion border, and significantly reduced the Olig2+ cell count at 3 dpi. Furthermore, cVNS significantly improved remyelination with 57.4 % versus sham at 11 dpi. Proteomic gene set enrichment analyses showed increased activation of (glutamatergic) synapse pathways in cVNS versus sham, most pronounced at 3 dpi. CONCLUSION: cVNS improved remyelination of an LPC-induced lesion. Possible mechanisms might include modulation of microglia and astrocyte activity, increased (glutamatergic) synapses and enhanced oligodendrocyte clearance after initial injury.

Lifestyle factors in multiple sclerosis disability progression and silent brain damage: A cross-sectional study.

OBJECTIVE: To determine the association between lifestyle risk factors with 1/ the Multiple Sclerosis Severity Score (MSSS) and 2/ ongoing subclinical brain damage in non-active MS patients on high-efficacy treatment. METHODS: Cross-sectional study in persons with Multiple Sclerosis (PwMS) investigating lifestyle factors including cognitive reserve (CR), physical activity (PA), smoking status, alcohol use, dietary habits, body mass index (BMI), blood pressure (BP) and cholesterol ratio. Data were collected through validated questionnaires, clinical and laboratory examination. Serum Neurofilament light chain (sNfL) levels were used as a proxy for ongoing brain damage in a subgroup of persons with non-active MS on high-efficacy treatment. Multiple regression analysis (MRA) models explored the relationship between lifestyle factors with the MSSS score and sNfL. RESULTS: 351 PwMS were included (43.04 ± 11.77 years, 69.8% female). Higher CR and PA were associated with a lower MSSS; overweight or obesity and higher systolic BP with a higher MSSS. The MRA model explained 22.2% of the variance for MSSS (R².255, adjusted R².222). Higher BMI and BP were related to lower sNfL. Twenty-3% (R².279, adjusted R².230) of the variance was explained in the MRA model for sNfL. CONCLUSION: Our study suggests an association between a 'brain healthy lifestyle' with disability progression in MS. A cognitive and physical active lifestyle alongside a normal body weight and blood pressure may help to prevent future disability in MS. Longitudinal and interventional research is necessary to gain insight in the causal pathway of these risk factors in preventing disability progression in MS.

Alemtuzumab in multiple sclerosis: A retrospective analysis of occult hemorrhagic magnetic resonance imaging lesions and risk factors.

BACKGROUND AND PURPOSE: Alemtuzumab, a monoclonal CD52 antibody, is a high-efficacy disease-modifying-therapy in relapsing-remitting multiple sclerosis (RRMS). Recently, intracerebral hemorrhage (ICH) was reported as a possible treatment-related adverse event. Arterial hypertension during infusion was suggested as a potential cause, although platelet or endothelial dysfunction may also contribute. This study aimed to screen for occult hemorrhagic cerebral lesions after alemtuzumab treatment and to further elucidate risk factors. METHODS: We included 30 RRMS patients who received alemtuzumab treatment at Ghent University Hospital or Sint-Jan Bruges Hospital. Retrospective data concerning vital signs, adverse effects and thrombocyte levels during treatment were collected. The occurrence of occult intracranial hemorrhagic lesions was assessed by magnetic resonance imaging with susceptibility-weighted imaging (SWI). RESULTS: The mean (standard deviation [SD]) systolic blood pressure (SBP) during the morning, afternoon and evening was 120 (3.38) mmHg during first administration and 114 (4.40) mmHg during second administration (N = 13). There was no significant increase in SBP when comparing morning, afternoon and evening per day, nor was there a significant difference in daily mean SBP between consecutive administration days. Thrombocyte count during treatment cycles ranged between 107 × 109 /L and 398 × 109 /L, with a mean (SD) absolute reduction of 59.3 × 109 /L (50.65) or a mean (SD) relative reduction of 25.0 (12.84)% (N = 20). No patient had ICH, nor did SWI show any cerebral microbleeds or other hemorrhagic lesions post-treatment (N = 23). CONCLUSIONS: In our patient population, alemtuzumab treatment was not associated with arterial hypertension, ICH or occult microbleeds. Possible differences in administration regimen (ambulatory vs. in-hospital setting) and patient population (cardiovascular risk) might explain an increased risk in different populations.