Decreased expression of breast cancer resistance protein in the duodenum in patients with obstructive cholestasis

Background/Aims: The expression of transporters involved in bile
acid homeostasis is differentially regulated during obstructive
cholestasis. Since the drug efflux transporter breast cancer
resistance protein (BCRP) is known to transport bile acids, we
investigated whether duodenal BCRP expression could be altered
during cholestasis. Methods: Using real-time RT-PCR analysis we
determined mRNA expression levels in duodenal tissue of 19
cholestatic patients. Expression levels were compared to 14 healthy
subjects. BCRP protein staining was determined in biopsies of 6
cholestatic and 6 healthy subjects by immunohistochemistry.
Results: We found that in patients with obstructive cholestasis
mean duodenal BCRP mRNA levels were significantly reduced to 53%
and mean protein staining was reduced to 57%. Conclusions: BCRP, a
transporter for bile acids and numerous drugs, appears to be
down-regulated in the human duodenum during cholestasis. The
clinical impact of these results has to be investigated in further
studies. Copyright (c) 2006 S. Karger AG, Basel.