Cystic fibrosis. Is treatment with ursodeoxycholic acid of value?

Liver and biliary diseases are common complications in cystic fibrosis (CF) and may even be so severe that liver transplantation is indicated in cases with mild pulmonary disease. The most common complications are steatosis, fibrosis/cirrhosis, micro gallbladder, cholelithiasis, and sclerosing cholangitis. Ursodeoxycholic acid (UDCA) has been used in the treatment of gallstones and pathological liver function in CF. The effect on gallstones has been contradictory, and the effect on liver function tests has been shown to be dose-dependent. A significantly better effect has been shown on liver function tests during treatment over 1 year with doses of 15-20 mg/kg/day. Although supplementation with taurine did not further improve this effect, it has been used in many studies. The biliary bile acid pool was enriched by UDCA from about 10% to 35-40%, but a similar increase was not seen in serum. We have studied the long-term effect of UDCA in 10 patients with liver fibrosis or cirrhosis and/or sclerosing cholangitis. Liver function and liver morphology examined on liver biopsies by both light and transmission electron microscopy (TEM) were followed for 2 years. Preliminary results of this study are encouraging. UDCA is an interesting drug which binds to the hepatocyte membranes, stabilizing membrane structure in in vitro experiments and increasing the bicarbonate excretion in bile in pigs. The mechanism of the effect of UDCA in CF might not only be an increased choleresis; further studies will focus on these aspects.