Recovery of OATP1B Activity after Living Kidney Transplantation in Patients with End-Stage Renal Disease.

Purpose: Recently, several studies have shown that renal failure decreases the metabolic clearance of drugs and the transportation capability of some drug transporters. However, whether organic anion transporting polypeptide (OATP)1B activities decrease in renal failure remains unknown. In this study, we measured plasma concentrations of coproporphyrin-I (CP-I), a specific endogenous OATP1B probe, in patients with end stage renal disease before and after living kidney transplantation and evaluated the effect of renal function on OATP1B activity. Methods: This prospective study recruited 13 patients with end-stage renal disease. Plasma CP-I concentrations were measured before and 7, 14, 30 and 90 days after living kidney transplantation. Results: Plasma CP-I concentrations decreased over time after living kidney transplantation and showed significant difference on day 90 compared with before living kidney transplantation [1.12 ± 0.59 vs 0.65 ± 0.27 ng/mL, p < 0.05 (95% CI of difference − 0.927, −0.013)]. A significant negative correlation was observed between estimated glomerular filtration rate and plasma CP-I concentration (r = −0.30, p < 0.05), suggesting recovery of OATP1B activity with improvement in renal function. Conclusions: OATP1B activity may decrease in renal failure and dose adjustment of OATP1B substrates may be needed in patients with renal failure. [ABSTRACT FROM AUTHOR]