Liver and biliary problems in cystic fibrosis

Abstract

Liver disease associated with cystic fibrosis has been increasingly diagnosed during recent years probably due to the combined effect of systematic hepatic assessment and reduced death from extra-hepatic causes of CF patients. In a group of 173 CF patients regularly followed at our Center, cumulative incidence of liver disease was 17% over a mean period of 10 years. Although it generally runs a mild course, it is considered a major complication of CF which may limit survival and quality of life of affected patients. CF-associated liver disease should be considered as the first inherited liver disorder in which the primary defect affects cholangiocyte transport systems. Although data assessing the effects of defective CFTR on cholangiocyte pathobiology are not yet available, the impaired secretory function of the biliary epithelium is considered responsible for reduced biliary fluidity and alkalinity and for subsequent bile duct damage by cytotoxic compounds or infectious agents. No clear association with specific CFTR mutations has been observed. Treatment with ursodeoxycholic acid, aimed at improving biliary secretion in terms of bile viscosity and bile acid composition, is currently the most useful therapeutic approach in CF-associated liver disease. Beneficial effects on liver biochemistry, hepatic excretory function, liver histology, and essential fatty acid status have been reported, but no long-term data exist on its effectiveness on clinically relevant outcomes, such as death or need for transplantation. The effectiveness of bile acid therapy may be higher if started in patients with early stage liver disease, before symptoms have become clinically evident. Early diagnosis and identification of CF patients who are more liable to develop liver disease should be actively pursued.