Sex-specific dynamic changes of serum short-chain fatty acids in rhesus monkeys during aging.

BACKGROUND

The potential association between short-chain fatty acids (SCFAs) and aging has gained increasing research attention. Although most studies have focused on fecal SCFAs, limited attention has been directed toward SCFAs in peripheral blood. Furthermore, this relationship remains insufficiently explored in non-human primate models.

METHODS

Serum samples were collected from eighty-five healthy Macaca mulatta. Serum SCFA concentrations were quantified using targeted gas chromatography-mass spectrometry. A subset of samples (19 males and 19 females) was further analyzed for reproductive and stress-related hormones using enzyme-linked immunosorbent assay kits.

RESULTS

Significant age-related alterations in SCFA concentrations were identified. Isobutyric acid levels increased with age, whereas acetic acid, propionic acid, and valeric acid levels decreased. Moreover, the direction of SCFA alterations differed between males and females. Integrated analysis with hormone assays demonstrated that these sex-specific differences in SCFAs were closely associated with the activity of the hypothalamic-pituitary-gonadal axis.

CONCLUSION

Serum SCFA profiles varied significantly with both age and sex. The secretion of reproductive and stress-related hormones was highly correlated with these differences. These findings provide new insights into how aging influences sex-dependent SCFA metabolism and may contribute to understanding the mechanisms underlying age- and sex-related physiological changes.