Background & aims: Cholestasis complicates total parenteral nutrition (TPN) in preterm infants. Ursodeoxycholic acid (UDCA) is used for several cholestatic problems. The hypothesis of this study was that intravenous UDCA prevents TPN-induced cholestasis by (1) maintaining normal basal and stimulated bile flow, (2) altering bile composition, and (3) changing hepatocyte membrane composition and Na+,K(+)-adenosine triphosphatase (ATPase) activity.
Methods: Three groups of piglets were studied: group 1 received sow's milk, groups 2 and 3 received TPN, and group 3 also received 100 mumol.kg-1.day-1 UDCA intravenously. After 3 weeks, basal and stimulated bile flow were measured. Cholesterol, bile acids, phospholipids, and phospholipid fatty acids were analyzed in bile, and fluidity, phospholipid fatty acid composition, and Na+,K(+)-ATPase were analyzed in hepatocyte membranes.
Results: Bile acid secretion and basal and stimulated bile flow were similar in control and UDCA-treated animals but reduced to < 50% in the TPN group. Bile acid-dependent and -independent bile flow were lower in the TPN group. UDCA did not normalize abnormalities in TPN-induced bile composition. Sinusoidal but not canalicular membrane fluidity was different in TPN than in control and UDCA-treated animals. UDCA also increased Na+,K(+)-ATPase activity. Bile and membrane phospholipid fatty acids reflected dietary fatty acids.
Conclusions: Intravenous UDCA improves bile flow and reduces bilirubin levels in the serum and liver in piglets with TPN-induced cholestasis.