Mechanisms of Caloric Restriction and Mimetic Vasoprotection in Old Arteries

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DESCRIPTION (provided by applicant): Advancing age is associated with the development of arterial dysfunction characterized by endothelial dysfunction and large artery stiffness. One hypothesis is that the chronic reduction of caloric intake (Caloric Restriction; CR) can activate cellular and molecular events that prevent age-related arterial dysfunction. This proposal aims to determine if lifelong caloric restriction (40%) and/or a pharmacological caloric restriction mimetic can prevent the age-related arterial dysfunction and the cellular and molecular mechanisms by which this may occur. Specifically, we will examine the effect of lifelong CR on the regulation and modulation of nuclear transcription factors, by acetylation, involved in the regulation of arterial oxidative stress, inflammation and apoptosis in middle-aged (MA) and older (O) mice. The specific aims are (1) to measure endothelium dependent dilation (EDD), nitric oxide (NO) bioavailability and stiffness in large arteries of MA/O mice and to determine if advancing age is associated with a pro-oxidative, -inflammatory, -apoptotic phenotype, (2) to determine if CR attenuates the activation and acetylation of the pro- oxidative, -inflammatory and -apoptotic signaling molecules; nuclear factor kappa B (NFkB), p53, and forkhead foxO (FoxO3a) via an increase a nuclear deacetylase SIRT-1 in MA/O mice and (3) to determine if activation of the nuclear deacetylase SIRT-1 can prevent the aged arterial phenotype and dysfunction. To do so, we will study young (Y: 4-6 mo), MA (18-20 mo) and O (29-31 mo) male B6D2F1 mice. Endothelial function, nitric oxide bioavailability, and larger artery stiffness will be measured. Oxidative stress, inflammatory cytokines, markers of apoptosis and activation/acetylation of NFkB, p53 and FoxO3a will be assessed in aortic lysates and endothelial cells. Lastly, we will utilize pharmacological inhibition of the nuclear deacetylase SIRT-1 to determine its role in age and caloric restriction-associated arterial function, oxidative stress, inflammation and apoptosis. The expected results will provide novel insight into the cellular and molecular mechanisms by which CR and CR mimetics preserve age-associated arterial function. PUBLIC HEALTH RELEVANCE: Advancing age is associated with arterial dysfunction. This proposal aims to determine if life-long caloric restriction and/or a pharmacological caloric restriction mimetic can prevent the age-related arterial function and the cellular and molecular mechanisms by which this may occur.