The Role of One-Carbon Metabolism After Ischemic Stroke in an Aged Mouse Model

Abstract Objectives Nutrition is a modifiable risk factor for stroke, which is one of the leading causes of death and disability world-wide. In humans deficiencies in one-carbon metabolism, including the methyltetrahydrofolate reductase (MTHFR) polymorphism, have been linked to increased risk of stroke. The Mthfr+/− mice mouse model mimics the phenotype of the MTHFR677C – >T polymorphism. In our work using in vitro and in vivo models of ischemic stroke we have observed decreased recovery after stroke through reduced neuronal and astrocyte viability and increased apoptosis in MTHFR-deficient mice. In addition, we have previously shown dietary supplementation of one-carbon metabolites increases neuroplasticity and reduced oxidative stress after ischemic stroke. Using the MTHFR-deficient mouse model, the aim of this study was to investigate the impact of dietary supplementation with one-carbon metabolites on stroke outcome. Methods Male Mthfr+/− and wildtype littermate control mice were aged to 1.5-year-old and were placed on control diet (CD) 4-weeks prior to sensorimotor cortex damage using photothrombosis (PT), a model for ischemic stroke. Post-operatively, one group of Mthfr+/− and wildtype littermate mice were fed a supplemented diet (SD) containing 5-methylTHF, vitamin B12, and choline. Four weeks after PT damage and SD motor function was assessed and brain tissue was processed to assess lesion volume and investigate biochemical and molecular changes. Results Mthfr +/− mice fed a SD after PT did not have an impaired neuroscore compared to CD Mthfr+/− mice. When compared to CD, SD Mthfr+/− mice were able to stay on the accelerating rotarod longer and travelled further, they also used their impaired forepaw more. Total homocysteine levels in plasma and lesion volume were reduced in SD Mthfr+/+ and Mthfr+/− mice. In the brain, within the damage site, there were reduced levels of apoptotic cell death and an increased neuroprotective cellular response in SD treated Mthfr+/− mice. Conclusions This study reveals a critical role for one-carbon supplementation in supporting improvement of function after ischemic stroke. Our data suggests that in stroke affected patients, nutritional supplementation maybe an important component to post-operative care, in addition to pharmacological and rehabilitation therapies. Funding Sources NSERC.