Serum bile acids in cystic fibrosis patients – glycodeoxycholic acid as a potential marker of liver disease

Background
Cystic fibrosis (CF) and CF-related liver disease can lead to disturbances in bile acid metabolism.
Aim
This study determined serum bile acid concentrations in CF to define their usefulness in liver disease assessment.
Methods
Primary, secondary and conjugated bile acid levels were measured in three CF groups (25 patients each) exhibiting: liver cirrhosis, other liver disease, no liver disease, and in 25 healthy subjects (HS).
Results
Bile acid levels were higher in CF patients than in HS, except for glycodeoxycholic acid (GDCA). However, bile acid concentrations did not differ between patients with cirrhosis and other liver involvement. GDCA and deoxycholic acid (DCA) differentiated CF patients with non-cirrhotic liver disease from those without liver disease (GDCA-AUC: 0.924, 95%CI 0.822–1.000, p<0.001; DCA-AUC: 0.867, 95%CI: 0.731–1.000, p<0.001). Principal component analysis revealed that in CF liver disease was related to GDCA, GGTP activity, severe genotype and pancreatic insufficiency.
Conclusions
A CF-specific bile acid profile was defined and shown to relate to liver disease. GDCA differentiates patients with non-cirrhotic liver involvement from those with no detectable liver disease. Hence, GDCA is a candidate for validation as a biomarker of non-cirrhotic progression of liver disease in CF.