Antioxidant response in patients with chronic hepatitis B or C.

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1 Antioxidant response in patients with chronic hepatitis B or C. Kamila Wójcik, Anna Piekarska, Elżbieta Jabłonowska Department of Infectious Diseases and Hepatology, Medical University of Lodz, Poland

2 Oxidative stress HCV core proteins and HBV X protein increase the mitochondrial production of reactive oxygen species (ROS),which induces oxidative stress and results in the peroxidation of membrane lipids and cell death. Okuda M. Gastroenterology 2002 Waris G. Mol Cell Biol 2001

3 Oxidative stress in HCV infection Reactive oxygen species (ROS) production can suppress HCV replication. Choi J. Hepatology 2004 Excessive production of ROS may cause hepatocyte damage. Mutlu-Turkoglu U. Res Commun Mol Pathol Pharmacol 1997 Antioxidant enzymes, such as Heme oxygenase-1 (HO- 1), induced in response to stressful stimuli, play a crucial role by suppressing inflammation and protecting against oxidative stress. Abraham NG. Pharmacol Rev 2008

4 Antioxidant response Upon oxidative stress, an adaptive antioxidant response is harnessed by the liver to sustain redox homeostasis and cellular integrity. Central to this self-protective antioxidant mechanism is the Nuclear factor (erythroidderived 2)-like 2 (Nrf2), encoded by the NFE2L2 gene. Nguyen T. Annu Rev Pharmacol Toxicol 2003

5 Antioxidant response

6 Antioxidant response Nrf2 binds to a conserved antioxidant response element (ARE) and is responsible for the transcriptional activation of cytoprotective genes. Bach1 (BTB and CNC homology 1, basic leucine zipper transcription factor 1) is a transcriptional repressor that antagonizes NRF2 binding to an antioxidant response element. Jyrkkänen HK. Biochem J 2011

7 Aims of study To analyze the antioxidant response and its regulatory factors in chronic hepatitis B and C.

8 Aims To examine the expression of the antioxidant genes GFER1(Growth factor erv1-like), HMOX-1 (heme oxygenase (decycling)-1) and NQO-1 (NAD(P)H:quinone oxidoreductase-1) in liver biopsy specimens obtained from patients with chronic hepatitis B or C. To investigate the importance of the regulatory genes NFE2L2 (nuclear factor erythroid 2-related factor 2) and Bach1 (BTB and CNC homology 1, basic leucine zipper transcription factor 1) in the antioxidant response.

9 Inclusion criteria Chronic hepatitis B (diagnosed as the presence of HBsAg, anti-hbeag and HBV-DNA (PCR) positivity and anti-hbe negativity for longer than 6 months). Chronic hepatitis C genotype 1 (based on anti- HCV and HCV-RNA (PCR) positivity lasting more than 6 months). All patients provided their written informed consent and the study was approved by the local Bioethics Committee.

10 Exclusion criteria cirrhosis (in liver biopsy), other causes of liver diseases, other systemic or inflammatory diseases, alcoholism, pregnancy, use of concomitant medication, including antioxidant vitamin and diet supplements within 6 months

11 Methods Liver biopsy was performed in all patients prior to treatment. The grade of inflammation and necrotic changes and the state of fibrosis were assessed according to the Batts and Ludwig scale. The hepatic expression of HMOX-1, GFER1, NQO-1,NFE2L2 and Bach-1 were determined using Real-Time PCR (RT-PCR).

12 Statistical analysis The Mann-Whitney test was used to evaluate differences between the examined groups. Correlations between hepatic expression of antioxidant genes HMOX-1, GFER1, NQO-1 and regulatory gene NFL2L2 and Bach-1 were analyzed with the Spearman rank correlation coefficient.

13 Results The study group consisted of 76 patients (42 with chronic HCV and 34 with chronic HBV infection).

14 Characteristics of the study group HCV infection (n=42) HBV infection (n=34) p MEDIAN LQ-UQ MEDIAN LQ-UQ Age in years >0.5 ALT U/l >0.5 HCV-RNA IU/ml HBV-DNA copies/ml Number of patients Fraction Number of patients Fraction G< >0.5 G , S<2 8 19, >0.5 S , Age >40 years >0.5 Age <40 years Women >0.5 Men

15 Hepatic expression of antioxidant genes HMOX1, GFER1, NQO-1 in chronic hepatitis B or C HCV infection HBV infection MEDIAN LQ-UQ MEDIAN LQ-UQ p HMOX < GFER NQO BACH NFE2L

16 Correlations between hepatic expression of antioxidant genes and the regulatory gene NFE2L2 in chronic hepatitis B or C HCV infection HBV infection Spearman`s rank correlation p-value Spearman`s rank correlation p-value GFER 1vs NFE2L2 HMOX-1 vs NFE2L2 NQO-1 vs NFE2L < < < <0.0001

17 Conclusions The hepatic expression of the antioxidant genes HMOX-1, GFER 1 and NQO-1 is higher in patients with chronic HBV than those with chronic HCV infection, and may be associated with better antioxidant response in the course of HBV infection. Dysregulation of NFE2L2 and Bach1 in patients with chronic hepatitis C is involved in impaired antioxidant response.