Many aspects of immunity decline with age, and NK immune cell function is no exception to this phenomenon. The age-related deterioration of immune function with age is linked to levels of an essential molecule called nicotinamide adenine dinucleotide (NAD+), which also declines with age. However, boosting NAD+ levels has been shown to improve immune function in mice. For example, studies have shown that increasing NAD+ levels by inhibiting an NAD+-consuming enzyme improves immunity to attenuate tumors in mice.
The NAD+ precursor NMN helps with age-related disorders like insulin insensitivity and metabolic impairments like obesity in aged mice. Also, since boosting NAD+ levels have been shown to work against tumors in mice, it may also potentially enhance anti-tumor NK cell activity. Figuring out whether NMN has these immunity-restoring effects in NK cells is critical for determining if it is the compound we’ve been looking for to restore their cytotoxicity.