fig2

Figure 2. Aging is associated with altered SCFA profiles in both mouse and human serum. (A) Flowchart of the study design. Young (8-week-old, n = 7) and aged (24-month-old, n = 7) C57BL/6J mice, as well as young human subjects (< 65 years old, n = 97) and aged human subjects (≥ 65 years old, n = 30), were enrolled. Serum samples were collected for targeted SCFA metabolomics analysis via GC/MS. (B) Quantification of individual SCFA concentrations in serum from young (blue) and aged (red) mice (n = 7 per group). (C) Quantification of individual SCFA concentrations in serum from young (cyan) and aged (purple) human subjects (young, n = 97; aged, n = 30). (D) Heatmap of differentially expressed SCFAs in mouse serum, with rows representing individual SCFAs and columns representing individual samples, clustered by group (young, blue; aged, red; n = 7 per group). The color scale indicates z-score-normalized SCFA concentrations. (E) Heatmap of differentially expressed SCFAs in human serum, with rows representing individual SCFAs and columns representing individual samples, clustered by group (young, cyan; aged, purple; young, n = 97; aged, n = 30). The color scale indicates z-score-normalized SCFA concentrations. Data are presented as mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.001 vs. young group (unpaired two-tailed Student’s t-test with Bonferroni correction for multiple comparisons). (A) was created in BioRender. Xie, Y. (2026) https://BioRender.com/mk23x70 and https://BioRender.com/1rzaufz.