A genetic deficiency in folic acid metabolism impairs recovery after ischemic stroke

Stroke is a leading cause of disability and death world-wide and nutrition is a modifiable risk factor for stroke. Metheylenetetrahydrofolate reductase (MTHFR) is an enzyme involved in the metabolism of folic acid, a B-vitamin. In humans, a polymorphism in MTHFR (677C→T) is linked to increased risk of stroke, but the mechanisms remain unknown. The Mthfr+/− mice mimic a phenotype described in humans at bp677. Using this mouse model, the aim of this study was to investigate the impact of MTHFR deficiency on stroke outcome. Male Mthfr+/− and wildtype littermate control mice were aged (~1.5-year-old) and trained on the single pellet reaching task. After which the sensorimotor cortex was then damaged using photothrombosis (PT), a model for ischemic stroke. Post-operatively, animals were tested for skilled motor function, and brain tissue was processed to assess cell death. Mthfr+/− mice were impaired in skilled reaching 2-weeks after stroke but showed some recovery at 5-weeks compared to wild types after PT damage. Within the ischemic brain, there was increased expression of active caspase-3 and reduced levels of phospho-AKT in neurons of Mthfr+/− mice. Recent data suggests that astrocytes may play a significant role after damage, the impact of MTHFR and ischemic investigated the impact of MTHFR-deficiency on astrocyte function. MTHFR-deficient primary astrocytes showed reduced cell viability after exposure to hypoxia compared to controls. Increased immunofluorescence staining of active caspase-3 and hypoxia-inducible factor 1-alpha were also observed. The data suggest that MTHFR deficiency decreases recovery after stroke by reducing neuronal and astrocyte viability. •Aged Mthfr+/− mice have impaired skilled reaching after stroke compared to Mthfr+/+.•Daily testing on skilled reaching task improved recovery in Mthfr+/− mice.•Mthfr+/− mice have mildly higher homocysteine, but lesion size does not differ.•There is lower neuronal survival within damage site of Mthfr+/− mice.•MTHFR deficiency results in reduced viability of primary astrocytes after hypoxia.