Nicotinamide adenine dinucleotide (NAD)

Nicotinamide Adenine Dinucleotide (NAD+) can directly and indirectly influence many key cellular functions, including metabolic pathways, DNA repair, chromatin remodeling, cellular senescence and immune cell function and is a coenzyme for redox reactions, making it central to energy metabolism. NAD+ is primarily found in three distinct cellular pools: 1) the cytosolic, 2) the mitochondrial, and 3) the nuclear pools [9]. It is also an essential cofactor for non-redox NAD+- dependent enzymes, including sirtuins, CD38 and poly(ADP-ribose) polymerases [1]. NAD+ is critical for maintaining tissue and metabolic homeostasis and for healthy aging, yet aging is accompanied by a gradual decline in tissue and cellular NAD+ levels [1]. In human primary cells, it is firmly established that there is an age-dependent decline of NAD+ levels, which ranges from 10% to 65%, depending on different organs and age [8]. NAD+ levels is linked causally to numerous aging-associated diseases, including cognitive decline, cancer, metabolic disease, sarcopenia and frailty [1]. Many of these aging-associated diseases can be slowed down and even reversed by restoring NAD+ levels [1].