Sex- and Diet- Dependent Effects of Microbiome-Derived Metabolite δ-Valerobetaine on Aging

Objectives: We recently found that δ-valerobetaine (δ-VB), a gut microbiome-derived metabolite, inhibits carnitine-dependent mitochondrial fatty acid metabolism and promotes fat accumulation in young mice fed to a Western diet but not in those on a chow diet. Previous studies demonstrated that aged mice have higher δ-VB levels in the brain than young mice, and δ-VB injections impair cognitive performance. Given that δ-VB may have more pronounced effects in aging, this study aimed to evaluate its sex- and diet-dependent effects in aged male and female mice fed either a standard or a Western diet.