Preventable decrements of cerebral microvascular volume and vasodilatation in a rat model of diet‐induced Vascular Cognitive Impairment: non‐invasive detection by absolute Near Infrared Spectroscopy

Abstract

The brain microvascular circulation has considerable structural plasticity and can expand or regress in response to metabolic and dietary challenges We hypothesized that such changes might underlie the association of folate deficiency and hyperhomocysteinemia with cerebrovascular and neurodegenerative disease. Previously, we found that dietary folate deficiency can impair cognition in Sprague Dawley rats and that this can be mitigated by adding methionine to the folate‐deficient diet. Separately, we used non‐invasive absolute Near Infrared Spectroscopy (NIRS) to obtain evidence of brain microvascular changes in folate‐deficient rats, finding diminished cerebral blood volume and vasoreactivity compared to controls. Here we extend these findings by showing that folate deficiency reproducibly diminishes cerebral blood volume and vascular reactivity, and that these changes can be reversed by methionine supplementation. Our findings are consistent with the hypothesis that reversible microvascular changes may contribute to cognitive impairment. The ability to non‐invasively manipulate, detect and measure such changes can help to understand the role of microvascular plasticity in dementia.Support: Israel Science Foundation and EU‐IRG