ABCB1 and chronic kidney disease: Degraeve et al. (2023) similarly found that regulation of ABCB1 expression by intestinal bacterial metabolites leads to changes in TAC PK. Guo et al., (2024) observed that IS upregulates the expression of ABCB1, ABCC2 in peripheral blood mononuclear cells from patients with CKD. Our previous study also found a correlation between plasma concentrations of microbiota-derived toxins IS and Hippuric acid (HA) and dose-corrected trough concentrations of TAC in liver transplant recipients (Zhu et al., 2022).