Investigation of Ornithine Carbamoyltransferase as a Biomarker of Liver Cirrhosis

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Objective Ornithine carbamoyltransferase (OCT) is a liver-specific mitochondrial matrix enzyme and potential biomarker of liver fibrosis. This study investigated the OCT levels in patients with chronic liver disease with or without cirrhosis in order to assess the usefulness of OCT as a biomarker of cirrhosis.
Methods The subjects included 440 Japanese patients with chronic liver disease and 80 control subjects. The patients were divided into two groups, those with and without cirrhosis, both of which were further stratified into high-OCT and low-OCT subgroups.
Results In the non-cirrhosis group, the patients with non-alcoholic steatohepatitis (NASH), alcoholic liver disease, primary biliary cirrhosis and primary sclerosing cholangitis (PSC) comprised the high-OCT subgroup, while the patients with hepatitis B, hepatitis C and autoimmune hepatitis formed the low-OCT subgroup. There were significant differences in the OCT levels, OCT/aspartate aminotransferase ratios and OCT/alanine transaminase (ALT) ratios between these two subgroups (p<0.001). The same findings were observed in the cirrhosis group. The OCT levels were markedly higher in the cirrhosis group than in the non-cirrhosis group, particularly among the patients with PSC (p<0.001). The most useful biomarker for predicting cirrhosis was the OCT/ALT ratio in the patients with hepatitis C and NASH and the OCT level in patients with PSC.
Conclusion The OCT level differs among patients with different chronic liver diseases. The role of OCT should be further evaluated in order to improve our understanding of the pathogenesis of these diseases. The OCT level is a useful surrogate marker of cirrhosis, particularly in PSC patients.