3-nitrotyrosine and Hepatitis-B--Chronic

The toxicity of nitric oxide is thought to be engendered, at least in part, by its reaction with superoxide yielding peroxynitrite, a potent oxidant that promotes the formation of nitrotyrosine within cells and tissue lesions. In this study we assessed the intrahepatic localization and distribution of the inducible nitric oxide synthase (iNOS) and nitrotyrosine (NTY) in patients with viral and non-viral liver disease.. We carried out single and double immunostaining experiments on cryostat liver biopsy sections using monoclonal antibodies against iNOS and NTY. We also performed a comparative analysis between the intrahepatic immunostaining score of NTY and the histological activity index of chronic viral hepatitis.. We found a marked hepatocellular expression of iNOS with a diffuse lobular pattern in all liver samples from patients with viral liver disease, whereas NTY localization was mainly restricted to cellular foci consisting of hepatocytes and Kupffer cells. Interestingly, we demonstrated by means of double immunostaining experiments the existence of hepatocellular co-localization of iNOS and NTY in the majority of NTY-expressing liver cells. The amount of NTY was significantly higher in liver biopsies from viral liver disease than in non-viral liver disease. In addition, a statistically significant association between the intrahepatic amount of NTY and the severity of viral liver disease was found.. Nitric oxide-mediated nitration of hepatocellular proteins is markedly induced in the inflamed liver tissue from patients with chronic viral hepatitis, and appears to be associated with the histological severity of viral chronic liver disease.

Topics: Adult; Female; Hepatitis; Hepatitis B, Chronic; Hepatitis C, Chronic; Humans; Immunologic Techniques; Liver; Male; Middle Aged; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Severity of Illness Index; Tissue Distribution; Tyrosine

During inflammation nitric oxide reacts at near diffusion limited rates with superoxide to form the strong oxidant peroxynitrite. Nitration on the ortho position is a major product of peroxynitrite attack on proteins. In the present study we investigated whether immunohistochemical detection of nitrotyrosine (footprint of peroxynitrite) can be associated with human hepatitis. Paraffin-embedded liver tissue biopsies from patients with chronic active hepatitis, chronic active hepatitis plus cirrhosis and chronic persistent hepatitis exhibit significant specific immunostaining with the antibody to nitrotyrosine. Positive staining was found in 57% and 72% of tissue specimens from patients with chronic hepatitis and cirrhosis, respectively. Immunohistochemical staining of nitrotyrosine residues was found in the hepatocytes and Kuppffer cells of the necrotic area. The presence of nitrotyrosine indicates that oxidants derived from nitric oxide such as peroxynitrite are generated in human hepatitis and may be involved in its pathogenesis.

Topics: Adult; Antibodies; Antibody Specificity; Female; Hepatitis B, Chronic; Hepatitis C, Chronic; Humans; Immunohistochemistry; Liver Cirrhosis; Male; Middle Aged; Nitrates; Tyrosine