Meta-analysis of NAD(P)(H) quantification results exhibits variability across mammalian tissues

Abstract

Nicotinamide Adenine Dinucleotide (NAD+) plays an important role in energy metabolism and signaling pathways controlling crucial cellular functions. The increased interest in NAD+ metabolism and NAD+-boosting therapies has reinforced the necessity for accurate NAD+ quantification. To examine the published NAD(P)(H) measures across mammalian tissues, we performed a meta-analysis of the existing data. An Ovid MEDLINE database search identified articles with NAD(P)(H) quantification results obtained from mammalian tissues published between 1961 and 2021. We screened 4890 records and extracted quantitative data, as well as the quantification methods, pre-analytical conditions, and subject characteristics. The extracted physiological NAD(P)(H) concentrations in various tissues from mice, rats, and humans, revealed an important inter- and intra-method variability that extended to recent publications. This highlights the relatively poor potential for cross-experimental analyses for NAD(P)(H) quantitative data and the importance of standardization for NAD(P)(H) quantification methods and pre-analytical procedures for future preclinical and clinical studies.

Conditional Cell Penetration of Masked CPPs by an ADEPT-like Approach

“…NAD is involved in many processes, acting as a coenzyme for redox reactions in energy metabolism or substrate for numerous enzymes and is therefore primarily found intracellularly at an estimated 200–500 μM concentration depending on tissue. − Extracellular NAD concentrations are very low. The median concentration of NAD in human whole blood was determined to be 44 μM, whereby the NAD content primarily originates from the red blood cells, where a median concentration of 46 μM was determined, while blood plasma only contained 0.4 μM . However, some tumor cells exhibited elevated NAD levels in the extracellular matrix, for example in prostate cancer cells .…”

“…The median concentration of NAD in human whole blood was determined to be 44 μM, whereby the NAD content primarily originates from the red blood cells, where a median concentration of 46 μM was determined, while blood plasma only contained 0.4 μM. 37 However, some tumor cells exhibited elevated NAD levels in the extracellular matrix, for example in prostate cancer cells. 38 Inflammation can also trigger release of NAD into the extracellular space, about 10 μM NAD in a mouse model.…”

A Simple, Fast, Sensitive LC-MS/MS Method to Quantify NAD(H) in Biological Samples: Plasma NAD(H) Measurement to Monitor Brain Pathophysiology

“…In addition, intracellular NAD + levels vary between 1 µM and 1 mM [28,38]. Because NAD + and NADH are present endogenously in a wide range of concentrations [53], their simultaneous analysis is very difficult. Nucleotides tend to fragment in the source, producing interfering isobaric species.…”

“…There have been reports of NADH and indirectly measured NAD + in human plasma using an enzymatic assay [57], but none in mouse plasma samples [53]. Although there are reports of measuring only NAD + in whole blood samples [16][17][18], there are no reports of measuring NADH.…”

“…Different compositions of extraction buffers can change NADH to NAD + (or vice versa in enzyme assay buffers), so this should be kept in mind when measuring NAD(H) (especially trace amounts of NADH). Clement et al measured NAD(H) in human plasma using LC-MS/MS [45], but there have been no reports of studies measuring NADH in mouse plasma [53].…”