Western diet feeding since adolescence impairs functional hyperemia probed by functional ultrasound imaging at adulthood and middle age: rescue by a balanced ω-3:ω-6 polyunsaturated fatty acids ratio in the diet

Obesity is a devastating worldwide metabolic disease, with the highest prevalence in children and adolescence. Obesity impacts neuronal function but the fate of functional hyperemia, a vital mechanism making possible cerebral blood supply to active brain areas, is unknown in organisms fed a high caloric Western Diet (WD) since adolescence. We mapped changes in cerebral blood volume (CBV) in the somatosensory cortex in response to whiskers stimulation in adolescent, adult and middle-aged mice fed a WD since adolescence. To this aim, we used non-invasive and high-resolution functional ultrasound imaging (fUS). Functional hyperemia is compromised as early as 3 weeks of WD and remains impaired thereafter. Starting WD in adult mice does not trigger the profound impairment in sensory-evoked CBV observed in young mice, suggesting a cerebrovascular vulnerability to WD during adolescence. A balanced ω-6:ω-3 polyunsaturated fatty acids ratio in WD achieved by docosahexaenoic acid supplementation is efficient to restore glucose homeostasis and functional hyperemia in adults. ### Competing Interest Statement The authors have declared no competing interest.