Fig. 3

Strategies for metabolomic analysis. Metabolomic profiles (light green) and collagen fiber quantitation data (yellow) were analyzed through differential gene expression and correlation analyses. The correlation of serological metabolites with fibrosis severity was investigated (dark green), and the list of significant metabolites was shortened. Unbiased clustering was performed through primary component analysis and heatmap analysis; the results are presented in Fig. 4A, B. The results of a comparison of the 16- and 32-week feeding durations in terms of metabolomic changes in the experimental mice (time effect) are presented in Fig. 5A, B (Wilcoxon rank-sum test). A multigroup comparison (Kruskal–Wallis test) was performed to differentiate between the significant metabolites. Significant metabolites were compared with significant collagen deposition (Kruskal–Wallis test; yellow squares); the correlation between collagen deposition and metabolome was investigated (correlation analysis; yellow square; Fig. 6A). The intersection of significant metabolites among the 32-week, WD, and HFC groups is depicted in Fig. 6B (dark-colored square), and the shortened metabolite list is presented in Fig. 6C