Objective: To study the expressions of cyclooxygenase-2 (COX-2) and Peroxisome proliferator-activated receptor gamma (PPARg) in liver of patients with hepatitis B virus (HBV) related acute-on-chronic liver failure (ACLF) and their correlation with clinical parameters.
Methods: 35 patients with ACLF, 35 patients with HBV related chronic liver failure (CLF), 27 patients with chronic hepatitis B(CHB) and 15 normal control were enrolled to study the expressions of COX-2 and PPARg in the liver tissues by immunohistochemical staining, and to analyze the correlation of the COX-2 and PPARg levels in liver tissues with clinical parameters.
Results: COX-2 was distinctly expressed in the cytoplasm of the hepatocytes, but PPARg was mostly expressed in the nuclei of the hepatocytes and also could be seen in the cytoplasm. The expressions of COX-2 in the liver of ACLF, CLF and CHB groups increased significantly as compared with NC group (z = -5.18, -4.50, -5.32, P is less than 0.01). The levels of COX-2 in ACLF livers also increased evidently as compared with CLF groups (z = -1.98, P is less than 0.05). The expression levels of PPARg in ACLF liver tissues were much higher than the other three groups, and statistical significances existed between ACLF group and the other two groups (CLF, NC groups) (z = -2.62, -4.28, P is less than 0.01). In ACLF group, the expression of COX-2 correlated with MELD score (r = 0.337, P is less than 0.05) and the expression of PPARg correlated with HBV DNA load (r = 0.348, P is less than 0.05). Clinical data showed that the levels of AST, TBil, CHOL, PT, INR, FIB and MELD score in ACLF group were significantly different from that in CLF, CHB and NC groups.
Conclusions: COX-2 expressed in liver may be a marker to reflect the degree of inflammation and injury of liver tissue. The PPARg expression of liver could be increased during chronic HBV infection and may be a protective mechanism against liver injury.