NAD+ depletion drives impaired endothelial cell proliferation and age-related vascular decline

Aging is accompanied by a decline in neovascularisation potential and increased susceptibility to ischemic injury. Here, we confirm the age-related impaired neovascularization following ischemic leg injury and impaired angiogenesis. The age-related deficits in angiogenesis arose primarily from diminished EC proliferation capacity, but not migration or VEGF sensitivity. Aged EC harvested from the mouse hindlimb displayed a pro-angiogenic gene expression phenotype, along with considerable changes in metabolic genes. Metabolomics analysis and 13C glucose tracing revealed that late passage HUVECs display impaired ATP production and altered glycolysis and TCA cycle intermediates, with significant shifts occurring at nicotinamide adenine dinucleotide (NAD⁺)-dependent steps along with NAD+ depletion, suggestive of compromised NAD⁺ metabolism. Supplementation with nicotinamide mononucleotide (NMN), a precursor of NAD⁺, enhances enhanced late-passage EC proliferation and sprouting angiogenesis from aged mice aortas. Taken together, our study illustrates the centrality of NAD+-dependent metabolism in the maintenance of EC proliferation capacity with age.