Background and purpose: Cyclosporine A (CyA) is an immunosuppressant drug used to treat various autoimmune diseases and transplantations. It has been reported that, in humans, CyA is metabolized by cytochrome P450 (CYP) 3A or excreted by P-glycoprotein/multidrug resistant protein (MRP) 2. Pravastatin, a statin, is used to treat hyperlipidemia and has also been reported to be excreted primarily by MRP2. We observed an increased blood CyA level in a patient following pravastatin administration, suggesting the possibility that CyA interacted with the pravastatin via MRP2. The aim of the study reported here was to investigate the effects of pravastation on CyA transport via MRP2 using a human colon adenocarcinoma (Caco-2) monolayer model system.
Methods: Calcein, a substrate of MRP families, was first added to the tissue culture medium of the Caco-2 cells, and CyA (5, 50 microM) and pravastatin (0.1, 1.0 mM) were then added to the apical and basolateral sides. After a 30-min incubation, calcein was effluxed from the Caco-2 cells and the level in the culture medium was assayed. CyA was then added to the tissue culture medium of the Caco-2 cells, and pravastatin (0.1, 0.5, 1.0 mM) was added to the apical and basolateral sides. After a 30-min incubation, CyA was effluxed from the Caco-2 cells, and the level in the culture medium was assayed.
Results: The calcein efflux to the apical side was decreased significantly by the addition of pravastatin (1.0 mM) and CyA (5, 50 microM), respectively. The CyA efflux to the apical side was decreased significantly by the addition of pravastatin (1.0 mM).
Conclusions: Based on these results, we suggest that CyA transport may be competitively inhibited by pravastatin via MRP2.