Uremic toxins inhibit transport by breast cancer resistance protein and multidrug resistance protein 4 at clinically relevant concentrations
Publication year
2011Source
PLoS One, 6, 4, (2011), article e18438ISSN
Publication type
Article / Letter to editor

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Organization
Paediatrics - OUD tm 2017
Physiology
Pharmacology-Toxicology
Laboratory of Genetic, Endocrine and Metabolic Diseases
IMM - Institute for Molecules and Materials
Nephrology
Journal title
PLoS One
Volume
vol. 6
Issue
iss. 4
Subject
IGMD 3: Genomic disorders and inherited multi-system disorders NCMLS 4: Energy and redox metabolism; IGMD 6: Hormonal regulation; IGMD 8: Mitochondrial medicine NCMLS 4: Energy and redox metabolism; IGMD 9: Renal disorder; IGMD 9: Renal disorder NCMLS 4: Energy and redox metabolism; IGMD 9: Renal disorder NCMLS 5: Membrane transport and intracellular motility; NCMLS 5: Membrane transport and intracellular motility IGMD 9: Renal disorder; IGMD 8: Mitochondrial medicine NCMLS 4: Energy and redox metabolism; IGMD 9: Renal disorder NCMLS 5: Membrane transport and intracellular motilityAbstract
During chronic kidney disease (CKD), there is a progressive accumulation of toxic solutes due to inadequate renal clearance. Here, the interaction between uremic toxins and two important efflux pumps, viz. multidrug resistance protein 4 (MRP4) and breast cancer resistance protein (BCRP) was investigated. Membrane vesicles isolated from MRP4- or BCRP-overexpressing human embryonic kidney cells were used to study the impact of uremic toxins on substrate specific uptake. Furthermore, the concentrations of various uremic toxins were determined in plasma of CKD patients using high performance liquid chromatography and liquid chromatography/tandem mass spectrometry. Our results show that hippuric acid, indoxyl sulfate and kynurenic acid inhibit MRP4-mediated [3H]-methotrexate ([3H]-MTX) uptake (calculated Ki values: 2.5 mM, 1 mM, 25 µM, respectively) and BCRP-mediated [3H]-estrone sulfate ([3H]-E1S) uptake (Ki values: 4 mM, 500 µM and 50 µM, respectively), whereas indole-3-acetic acid and phenylacetic acid reduce [3H]-MTX uptake by MRP4 only (Ki value: 2 mM and IC50 value: 7 mM, respectively). In contrast, p-cresol, p-toluenesulfonic acid, putrescine, oxalate and quinolinic acid did not alter transport mediated by MRP4 or BCRP. In addition, our results show that hippuric acid, indole-3-acetic acid, indoxyl sulfate, kynurenic acid and phenylacetic acid accumulate in plasma of end-stage CKD patients with mean concentrations of 160 µM, 4 µM, 129 µM, 1 µM and 18 µM, respectively. Moreover, calculated Ki values are below the maximal plasma concentrations of the tested toxins. In conclusion, this study shows that several uremic toxins inhibit active transport by MRP4 and BCRP at clinically relevant concentrations.
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- Academic publications [204859]
- Electronic publications [103204]
- Faculty of Medical Sciences [81031]
- Faculty of Science [32287]
- Open Access publications [71761]
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