Chemical structures and descriptions
NAD metabolome
What is measured?
Nicotinic acid riboside (NAR), nicotinic acid adenine dinucleotide (NAAD), nicotinic acid (NA), nicotinamide riboside (NR), nicotinamide N-oxide (NAMO), nicotinamide mononucleotide (NMN), nicotinamide adenine dinucleotide phosphate (reduced form) (NADPH), nicotinamide adenine dinucleotide phosphate (oxidized form) (NADP), nicotinamide adenine dinucleotide (reduced form) (NADH), nicotinamide adenine dinucleotide (oxidized form) (NAD), nicotinamide (NAM), 4-methylpyridine (m4PY), 2-methylpyridine (m2PY), and 1-methylnicotinamide (mNAM).
Method(s): LC-MS/MS
The NAD metabolome
The profile includes NAD/NADH and NADP/NADPH pairs that are essential for electron transfer in biochemical pathways, with the former reflecting NAD status. NR and NMN serve as NAD precursors that are given as supplements. The profile also includes mNAM which is a NAD catabolite that is further oxidized to m2PY, and m4PY (mice), and NAMO that is formed as a result of the oxidation of NAM.
Indication(s)
The NAD metabolome is currently investigated in relation to  mitochondrial function, energy metabolism, cellular senescence, epigenetic regulation, and neuroinflammation and is relevant to research investigating neurodegenerative diseases, type 2 diabetes, insulin resistance and obesity.
Specimen, collection and processing
Whole blood should be sampled in cold EDTA tubes, preferentially put in liquid nitrogen, and stored at –80°C. Freeze-thawing causes preanalytical distortion of the metabolite profile, including rapid degradation of NADH (and NADPH), and a substantial formation of NAM.
Transportation
Frozen, on dry ice. (for general instruction on transportation, click here)
Reported values, interpretation
The reported values for the NAD metabolome vary substantially across publications, partly related to preanalytical degradation and metabolite interconversion in hemolyzed blood. After supplementation with NR, NAAD in particularly, but also NAMO, m2PYand mNAM may increase more than 10-fold from values close to LOD to several micromolar. Also, NAD and NADH may increase more that 2-fold following supplementation.
Reported values (µmol/L): NAR, 3-15; NAAD, 0.005-1; NA, 0-0.6; NR, 0-9; NAMO, 0.005-1.5; NMN, 2-10; NADPH, 1-4; NADP, 10-40; NADH, 0.5-3; NAD, 10-50; NAM, 5-25; m2PY, 0-20; mNAM, 0.1-3.
Literature
1. Iqbal, T., & Nakagawa, T. (2024). The therapeutic perspective of NAD+ precursors in age-related diseases. Biochem Biophys Res Commun, 702, 149590.
2. Migaud, M. E., Ziegler, M., & Baur, J. A. (2024). Regulation of and challenges in targeting NAD+ metabolism. Nat Rev Mol Cell Biol, 25(10), 822-840.
3. Gindri, I. M., Ferrari, G., Pinto, L. P. S., Bicca, J., Dos Santos, I. K., Dallacosta, D. et al. (2024). Evaluation of safety and effectiveness of NAD in different clinical conditions: a systematic review. Am J Physiol Endocrinol Metab, 326(4), E417-E427.