Novel NAD+ metabolomic technologies and their applications to Nicotinamide Riboside interventions

Nicotinamide adenine dinucleotide (NAD+) is a cofactor in hydride transfer reactions and consumed substrate of several classes of glycohydrolyitc enzymes, including sirtuins. NAD+, its biosynthetic intermediates, breakdown products, and related nucleotides (the NAD metabolome) is altered in many metabolic disorders, such as aging and obesity. Supplementation with the novel NAD+ precursor, nicotinamide riboside (NR), ameliorates these alterations and opposes systemic metabolic dysfunctions in rodent models. Based on the hypothesis that perturbations of the NAD metabolome are both a symptom and cause of metabolic disease, accurate assessment of the abundance of these metabolites is expected to provide insight into the biology of diseases and the mechanism of action of NR in promoting metabolic health. Current quantitative methods, such as HPLC, lack specificity and sensitivity to detect distinct alterations to the NAD metabolome. In this thesis, I developed novel sensitive, accurate, robust liquid chromatography mass spectrometry methodologies to quantify the NAD metabolome and applied these methods to determine the effects of disease states and NR supplementation on NAD+ metabolism. My investigations indicate that NR robustly increases the NAD metabolome, especially NAD+ in a manner kinetically different than any other NAD+ precursor. I provide the first evidence of effective NAD+ supplementation from NR in a healthy, 52 year old human male, suggesting the metabolic promoting qualities of NR uncovered in rodent studies are translatable to humans. During my investigation of NR supplementation, my work establishes an unexpected robust, dramatic increase in deamino–NAD+, NAAD, directly from NR, which I argue could serve as an accessible biomarker for efficacious NAD+ supplementation and the effect of disease upon the NAD metabolome. Lastly, I further establish NR as a general therapeutic against metabolic disorder by detailing its ability to oppose aspects of chronic alcoholism and diabetes mellitus.