Large Intravenous Loads of Bilirubin Photoconversion Products, in Contrast to Bilirubin, Do Not Cause Cholestasis in Bile Acid-Depleted Pigs

Abstract

Background: Large intravenous bilirubin infusions in bile acid-depicted pigs (BADF) destroy hepatocyte canalicular membrane microvilli (CMV) and cause cholestasis. This study examines whether bilirubin photoconversion product infusions do the same. Methods: The effects of systemic infusion of 135 µmol - kg⁻¹ body weight bilirubin photoconversion products on CMV density and cholcretic response to intruportal bile acid infusion were studied in BADP. Furthermore, the effects of 135 µmol - kg⁻¹ b.w. bilirubin infusion, cither through an artcriovenous bilirubin photoconversion shunt device (PCD) or intravenously, were measured in PCD-connected BADP. Results: Intravenous bilirubin photoconversion product infusions affected neither the CMV density nor the choleretic response to cholic acid infusion, and neither did bilirubin infusion through the PCD. In contrast, intravenous bilirubin infusion caused canalicular injury and cholestasis in four of six PCD-connected 13ADP. Conclusion: Bilirubin photo-conversion products do not destroy CMV or cause cholestasis in BADP. A bilirubin photoconversion shunt device can confer cholestasis protection to bilirubin-loaded BADP.

Key Words:

• Bile secretion
• bilirubin
• bilirubin photoconversion
• canalicular membrane
• cholestasis protection
• cholic acid
• liver
• pig