Brief Article
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World J Hepatol. Apr 27, 2013; 5(4): 206-213
Published online Apr 27, 2013. doi: 10.4254/wjh.v5.i4.206
Differential expression of hepatic apurinic/apyrimidinic endonuclease 1, a DNA repair enzyme, in chronic hepatitis
Shinichi Sumiyoshi, Yoshimasa Kobayashi, Kinya Kawamura, Kazuhito Kawata, Hirotoshi Nakamura
Shinichi Sumiyoshi, Yoshimasa Kobayashi, Kinya Kawamura, Kazuhito Kawata, Hirotoshi Nakamura, Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, Shizuoka 431-3192, Japan
Author contributions: Sumiyoshi S, Kawamura K and Kawata K performed the majority of experiments; Sumiyoshi S, Kobayashi Y and Nakamura H designed the study and wrote the manuscript.
Correspondence to: Shinichi Sumiyoshi, MD, Second Division, Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan. sumishin@hmedc.or.jp
Telephone: +81-53-4352263 Fax: +81-53-4352354
Received: August 7, 2012
Revised: November 22, 2012
Accepted: December 5, 2012
Published online: April 27, 2013
Abstract

AIM: To determine hepatic expression of apurinic/apyrimidinic endonuclease 1 (APE-1) and 8-hydroxydeoxyguanosine (8-OHdG) in patients with chronic hepatitis B and C.

METHODS: Liver biopsies were obtained from 27 patients with chronic hepatitis B virus (HBV), 30 with chronic hepatitis C virus (HCV), 6 with autoimmune hepatitis (AIH), and 6 with primary biliary cirrhosis (PBC). Normal liver tissue was obtained from surgical resection specimens of four patients. Hepatic APE-1 protein and mRNA expression were assayed by Western blot and by real-time polymerase chain reaction, respectively. Hepatocellular APE-1 and 8-OHdG expression were determined by immunohistochemistry.

RESULTS: The staining intensity of hepatocellular nuclear APE-1 was lower in the HBV group than in the other groups (P < 0.05). Hepatic APE-1 protein levels were reduced in the HBV group relative to the other groups. Hepatic APE-1 mRNA levels were also lower in the HBV group. The proportion of hepatocytes with 8-OHdG-positive nuclei was increased in the HCV, AIH and PBC groups (P < 0.05), but not in the HBV group. Hepatocellular nuclear APE-1 levels were positively correlated with hepatocellular 8-OHdG levels in both the HBV and HCV groups (HBV, r = 0.34, P < 0.05; HCV, r = 0.54, P < 0.01).

CONCLUSION: An imbalance between oxidative DNA damage and APE-1 expression may contribute to hepatocarcinogenesis in chronic viral hepatitis.

Keywords: Apurinic/apyrimidinic endonuclease 1, 8-hydroxydeoxyguanosine, Oxidative stress, Viral hepatitis