Sirtuin is an essential factor that delays cellular senescence and extends the organismal lifespan through the regulation of diverse cellular processes. Suppression of cellular senescence by sirtuin is mainly mediated through delaying the age-related telomere attrition, sustaining genome integrity and promotion of DNA damage repair.
In addition, sirtuin modulates the organismal lifespan by interacting with several lifespan regulating signaling pathways including insulin/IGF-1 signaling pathway, AMP-activated protein kinase, and forkhead box O. Although still controversial, it is suggested that the prolongevity effect of sirtuin is dependent with the level of and with the tissue expression of sirtuin. Since sirtuin is also believed to mediate the prolongevity effect of calorie restriction, activators of sirtuin have attracted the attention of researchers to develop therapeutics for age-related diseases.
Resveratrol, a phytochemical rich in the skin of red grapes and wine, has been actively investigated to activate sirtuin activity with consequent beneficial effects on aging. This article reviews the evidences and controversies regarding the roles of sirtuin on cellular senescence and lifespan extension, and summarizes the activators of sirtuin including sirtuin-activating compounds and compounds that increase the cellular level of nicotinamide dinucleotide (NAD).
FULL TEXT: BMB Reports
Older men (n = 12) and women (n = 18) 65–80 years of age completed twelve weeks of exercise and took either a placebo or resveratrol (500 mg/day) to test the hypothesis that resveratrol treatment combined with exercise would increase mitochondrial density, muscle fatigue resistance, and cardiovascular function more than exercise alone.
Contrary to our hypothesis, aerobic and resistance exercise coupled with resveratrol treatment did not reduce cardiovascular risk further than exercise alone. However, exercise added to resveratrol treatment improved the indices of mitochondrial density, and muscle fatigue resistance, more than placebo and exercise treatments.
In addition, subjects that were treated with resveratrol had an increase in knee extensor muscle peak torque (8%), average peak torque (14%), and power (14%) after training, whereas exercise did not increase these parameters in the placebo-treated older subjects. Furthermore, exercise combined with resveratrol significantly improved mean fiber area and total myonuclei by 45.3% and 20%, respectively, in muscle fibers from the vastus lateralis of older subjects.
Together, these data indicate a novel anabolic role of resveratrol in exercise-induced adaptations of older persons and this suggests that resveratrol combined with exercise might provide a better approach for reversing sarcopenia than exercise alone.
FULL TEXT: J Gerontol A Biol Sci Med Sci
EDITOR’S NOTE: ‘sarcopenia’ is muscle-wasting.
Enzymes like telomerase and resveratrol, though not the Fountain of Youth unto themselves, offer tantalizing clues to how we might someday soon unravel the aging process.