Age-associated changes in oxidative stress and NAD+ metabolism in human tissue

Massudi H, Grant R, Braidy N, Guest J, Farnsworth B, Guillemin GJ · PLoS One

Tissue NAD+ fell with age in both sexes (post-pubescent males r=-0.71, p=0.0001; females r=-0.54, p=0.01). PARP activity rose with age in males across the whole 0-77 range (r=0.77, p<0.0001), but the correlation did not survive excluding newborns (r=0.40, p=0.09). SIRT1 activity fell with age in post-pubescent males (r=-0.61, p=0.007) and showed no significant change in females. NAD+ level and SIRT1 activity did not correlate with each other (r=0.06, p=0.77).

Population

Human pelvic skin samples from donors aged newborn to 77 years

Intervention

None — tissue NAD+, PARP activity, SIRT1 activity and DNA damage measured against age

Comparator

Age as a continuous variable

Limitations

Cross-sectional and correlational — cannot establish that falling NAD+ causes anything. One tissue (skin), one cohort, and most associations held only in males.