High‐Fat‐Diet Intake Enhances Cerebral Amyloid Angiopathy and Cognitive Impairment in a Mouse Model of Alzheimer's Disease, Independently of Metabolic Disorders

BACKGROUND The high-fat Western diet is postulated to be associated with the onset and progression of Alzheimer's disease (AD). However, the role of high-fat-diet consumption in AD pathology is unknown. This study was undertaken to examine the role of high-fat-diet intake in AD. METHODS AND RESULTS 5XFAD mice, a useful mouse model of AD, and control wild-type mice were fed (1) high-fat diet or (2) control diet for 10 weeks. The effects on cerebral AD pathology, cognitive function, and metabolic parameters were compared between each group of mice. High-fat diet significantly enhanced cerebrovascular β-amyloid (Aβ) deposition (P<0.05) and impaired cognitive function (P<0.05) in 5XFAD mice, but not in wild-type mice. High-fat diet enhanced hippocampal oxidative stress (P<0.05) and NADPH oxidase subunits, gp91(phox) (P<0.01) and p22(phox) (P<0.01) in 5XFAD mice, but not in wild-type mice. Furthermore, high-fat diet reduced cerebral occludin (P<0.05) in 5XFAD mice, but not in wild-type mice. Thus, 5XFAD mice exhibited greater susceptibility to high-fat diet than wild-type mice regarding cerebrovascular injury and cognitive impairment. On the other hand, 5XFAD mice fed high-fat diet exhibited much less increase in body weight, white adipose tissue weight, and adipocyte size than their wild-type counterparts. High-fat diet significantly impaired glucose tolerance in wild-type mice but not in 5XFAD mice. Thus, 5XFAD mice had much less susceptibility to high-fat-diet-induced metabolic disorders than wild-type mice. CONCLUSIONS High-fat diet, independently of metabolic disorders, significantly promotes the progression of AD-like pathology through enhancement of cerebral amyloid angiopathy and oxidative stress.