P-glycoprotein (ABCB1) is involved in vitamin K efflux

International audience; ABCB1 (P-glycoprotein/MDR1) is a multidrug efflux transporter that has previously been involved in cholesterol and vitamin D metabolism. Our aim was to explore whether ABCB1 is also involved in vitamin K efflux. Vitamin K apical efflux was significantly decreased in presence of ABCB1 inhibitor in Caco-2 cells (− 20.4%; p < 0.05) and increased in Griptite cells overexpressing ABCB1 (+40.7%; p < 0.05). In vivo, the vitamin K postprandial response was higher in male Abcb1 − /− mice after gavage compared to control animals (+115%; p < 0.05), but was unchanged in female mice. Finally, a vitamin K transintestinal efflux and a biliary vitamin K efflux were observed, but the specific involvement of ABCB1 could not be confirmed in these pathways. Overall, we showed for the first time that ABCB1 is involved in enterocyte vitamin K efflux in both cell and mouse models and regulates vitamin K absorption in mice. Recently, the multidrug membrane transporter ABCB1 (Sharom, 2011) has been identified to contribute to the intestinal transport of vitamin D (Margier et al., 2019