Fig. 5

Alterations of fecal and serum metabolome across different CKD-severities. Orthogonal partial least squares discriminant analysis (OPLS-DA) of metabolites in the A fecal and B serum samples, with the ellipse represents the 95% confidence interval. Comparisons of C fecal and D serum metabolites related to arginine and proline metabolism, arachidonic acid metabolism, ubiquinone and other terpenoid-quinone biosynthesis, and glutathione metabolism showed significant elevation or depletion stratified by the severity of chronic kidney disease (CKD). Statistical analysis was performed by Wilcoxon rank-sum test (*P < 0.05, **P < 0.01, ***P < 0.001). Benjamini–Hochberg procedure was employed for the multiple test adjustments. GSH metabolism, glutathione metabolism; AA metabolism, Arachidonic acid metabolism; Ubi biosynthesis, ubiquinone and other terpenoid-quinone biosynthesis; mod-CKD, moderate CKD; ESRD, end-stage renal disease; LTB4, leukotriene B4; TXB2, thromboxane B2; 12-KETE, 12-keto-5,8,10,14-eicosatetraenoic acid