Extended Data Fig. 4: NAD+/ NADH ratio, and the glutathione/oxiglutathion oxidative stress pathway.
From: Healthy aging and muscle function are positively associated with NAD+ abundance in humans
(a) NAD + to NADH ratio (log2 scale) in young and older adults belonging to trained, normal, and impaired aging groups. (b) The glutathione – oxliglutathione oxidative stress pathway for metabolites measured in this study. Glutamate and glycine feed into glutathione production. Conversion of glutathione to oxiglutathione results in quenching of free radicals, whereby the ratio of glutathione to oxiglutathione is indicative of this process. A byproduct of this pathway is ophthalmic acid (data presented in Fig. 2c). Data suggests an increase of the oxidative milieu in the aged groups relative to young. Sample sizes are: young n = 12, older adults; trained n = 17, Normal=17, impaired=6. Significance was determined using an empirical Bayes moderated t test (two-sided, p values adjusted for multiple comparisons between groups, * p < 0.05, ** p < 0.01, n.s. = not significant). Boxplots: Inner line within the box is the median of the data, the box extends to the upper and lower quartile of the dataset (25% of the data above and below the median), whiskers (dashed lines) represent up to 1.5 times the upper or lower quartiles, circles beyond the whisker represent individual data points outside this range. Source data: Statistical_Source_Data.csv, all exact p values for comparison between groups are listed therein.
