In vivo NAD assay reveals the intracellular NAD contents and redox state in healthy human brain and their age dependences

Zhu XH, Lu M, Lee BY, Ugurbil K, Chen W · Proceedings of the National Academy of Sciences

Non-invasive 7-tesla measurement of brain NAD in living people found NAD+ (r=-0.75), total NAD (r=-0.57) and the NAD+/NADH redox potential (r=-0.76) all falling with age while NADH rose (r=0.68) — the first in vivo evidence, in the authors' words, connecting human aging to cerebral NAD content and redox state, matching the direction ex vivo rodent work had shown.

Population

Healthy adult volunteers scanned at 7 tesla

Intervention

None — magnetic resonance spectroscopy measurement of intracellular NAD+ and NADH in intact brain

Comparator

Age as a continuous variable

Limitations

Seventeen subjects aged 21-68, cross-sectional, single organ; the technique requires a 7T scanner and has not been applied to joint tissue. The near-perfect linear fits the paper reports (R-squared at or above 0.99) are on three averaged age-group means rather than on individuals, whose correlations run r=-0.57 to -0.76, and no p-values are given for them.