Circulating antioxidants as determinants of the rate of biological aging in pigtailed macaques (Macaca nemestrina)

The effect of antioxidant activity on the rate of biological aging was studied in 39 pigtailed macaques (Macaca nemestrina) 7-30 years of age. Scores of seven antioxidant compounds (vitamins C and E, carotenoids, urate, bilirubin, ceruloplasmin, and albumin) were combined to produce an antioxidant variable (AOx) that was tested for correlation with a second composite variable, rate of biological aging (RBA). RBA was formed from seven physiological variables that met a stringent set of criteria as biomarkers of aging. Potential effects of disease on RBA and AOx were excluded by experimental design and by statistical control using a composite index of disease (Dis) that was based on four measures of clinical history and pathology. The study produced three salient findings: (1) there was a significant inverse relation between AOx and RBA (i.e., animals that had high AOx scores had low RBA scores and vice versa); (2) the relation was independent of Dis effects, and (3) there was no significant relation between AOx and Dis independent of RBA (i.e., the correlation between AOx and Dis was dependent on the correlation of AOx with RBA). These results further validated the RBA variable as a measure of the rate of biological aging and supported the concept that antioxidant activity influences both the rate of biological aging and vulnerability to disease.