Roles of NAD⁺in Health and Aging

NAD + , the essential metabolite involved in multiple reactions such as the regulation of cellular metabolism, energy production, DNA repair, mitophagy and autophagy(definition), inflammation, and neuronal function, has been the subject of intense research in the field of aging and disease over the last decade.NAD + levels decline with aging and in some age-related diseases, and reduction in NAD + affects all the telomere(definition) attrition, cellular senescence(definition))." style="text-decoration:underline dotted; text-underline-offset:2px; cursor:help;">hallmarks of aging(definition).Here, we present an overview of the discovery of NAD + , the cellular pathways of producing and consuming NAD + , and discuss how imbalances in the production rate and cellular request of NAD + likely contribute to aging and age-related diseases including neurodegeneration.Preclinical studies have revealed great potential for NAD + precursors in promotion of healthy aging and improvement of neurodegeneration.This has led to the initiation of several clinical trials with NAD + precursors to treat accelerated aging, age-associated dysfunctions, and diseases including Alzheimer's and Parkinson's.NAD supplementation has great future potential clinically, and these studies will also provide insight into the mechanisms of aging. THE DISCOVERY OF NAD +N icotinamide adenine dinucleotide (NAD) can exist in two forms, the oxidized form, NAD + , and the reduced form, NADH, which are coupled together and known as a "redox couple."While they are chemically similar, here we mainly focus on NAD + .NAD + is an essential metabolite for life and health, as it participates in dozens of known cellular reactions that affect redox status, energy production, and metabolic homeostasis, in addition to having anti-inflammatory properties, and assisting in stem cell rejuvenation, autophagy/mitophagy, nuclear-mitochondrial communication,