Cyanidin 3-glucoside targets a hepatic bilirubin transporter in rats - 08/12/22

Abstract |
One of the organ-specific functions of the liver is the excretion of bilirubin into the bile. Membrane transport of bilirubin from the blood to the liver is not only an orphan function, because there is no link to the protein/gene units that perform this function, but also a poorly characterised function. The aim of this study was to investigate the pharmacology of bilirubin uptake in the liver of the female Wistar rat to improve basic knowledge in this neglected area of liver physiology. We treated isolated perfused livers of female rats with repeated single-pass, albumin-free bilirubin boli. We monitored both bilirubin and bilirubin glucuronide in perfusion effluent with a bio-fluorometric assay. We tested the ability of nine molecules known as substrates or inhibitors of sinusoidal membrane transporters to inhibit hepatic uptake of bilirubin. We found that cyanidin 3-glucoside and malvidin 3-glucoside were the only molecules that inhibited bilirubin uptake. These dietary anthocyanins resemble bromosulfophthalein (BSP), a substrate of several sinusoidal membrane transporters. The SLCO-specific substrates estradiol-17 beta-glucuronide, pravastatin, and taurocholate inhibited only bilirubin glucuronide uptake. Cyanidin 3-glucoside and taurocholate acted at physiological concentrations. The SLC22-specific substrates indomethacin and ketoprofen were inactive. We demonstrated the existence of a bilirubin-glucuronide transporter inhibited by bilirubin, a fact reported only once in the literature. The data suggest that bilirubin and bilirubin glucuronide are transported to the liver via pharmacologically distinct membrane transport pathways. Some dietary anthocyanins may physiologically modulate the uptake of bilirubin into the liver.
Le texte complet de cet article est disponible en PDF.Graphical Abstract |
Highlights |
• | The dietary flavonoid cyanidin 3-glucoside inhibits hepatic uptake of bilirubin in the isolated perfused rat liver. |
• | The increase in bilirubin triggered by cyanidin 3-glucoside inhibits the reuptake of bilirubin glucuronide. |
• | Oatp (SLCO) substrates exclusively inhibit the reuptake of bilirubin glucuronide. |
• | Some nonsteroidal anti-inflammatory drugs have no effect on bilirubin uptake. |
Abbreviations : BR, BRG, C3G, E17G, M3G, P3G, PRV, TC
Keywords : Bilirubin, Sinusoidal transporter, Cyanidin-3-O-beta-glucopyranoside, Pravastatin, Estradiol-17 betaglucuronide, Organic anion transporters
Plan
Vol 157
Article 114044- janvier 2023 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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