Hepatobiliary membrane transporters involving in the formation of cholesterol calculus.

Background: Cholecyst cholesterol lithiasis is a common disease of the digestive system; however, the cause of lithogenesis is still unclear. Although bile salt export pump (BSEP), multidrug resistance protein 2 (MRP2), and multiple drug resistance 3 (MDR3) are 3 well-known transporting proteins, their effect on lithogenesis has not been elucidated. This study was undertaken to examine the relationship between BSEP, MRP2, MDR3, and cholesterol calculus formation.
Methods: Liver tissue specimens were taken from 20 patients with cholesterol calculus and from 10 patients with normal liver. mRNA and protein expressions of BSEP, MRP2, and MDR3 were determined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot, respectively. This study was approved by the ethics committee of China Medical University and informed consent was obtained from all patients.
Results: mRNA and protein expressions of BSEP, MRP2, and MDR3 were significantly down-regulated in the liver tissue of the patients with cholesterol calculus compared with normal liver tissue of the controls.
Conclusion: The down-regulation of BSEP, MRP2, and MDR3 may be correlated with the formation of cholesterol calculus.