BCL-2 and BAX expression and cell proliferation, after partial hepatectomy with and without ischemia, on cholestatic liver in rats: an experimental study.

BACKGROUND: Liver regeneration after partial hepatectomy (PHx) is regulated by several factors that activate or inhibit hepatocyte proliferation. Apoptosis seems to play an important role in cellular proliferation and liver regeneration. This study investigates the expression apoptosis-associated genes bcl-2 and bax, and the presence of apoptosis and cell proliferation after PHx, in normal and jaundiced rats with or without superimposed ischemia. MATERIALS AND METHODS: The study included 50 male Wistar rats assigned into; five groups (10 rats each). On day 0, rats of groups II, IV, and V underwent common bile duct ligation (BDL). On day 10, total liver ischemia (TLI) (occlusion of hepatic artery and portal vein-TLI) for 30 min was performed on animals of group V. When TLI was completed, all 30 animals (of groups I, IV, and V) underwent PHx (68%). Animals of group III underwent only TLI for 30 min. Rats of groups I, IV, and V were sacrificed 24 and 48 h after PHx was completed. Rats of group II were sacrificed 10, 11, and 12 days after BDL. Rats of group III were sacrificed immediately, 24 and 48 h after TLI completion. Liver tissue was obtained and pathologic examination included: (a) H&E stain, (b) in situ hybridization (detection of bcl-2 and bax mRNA) in paraffin sections, (c) Western blot analysis for the evaluation of bcl-2 and bax protein levels, (d) in situ hybridization (TUNEL) for the detection of apoptotic bodies, and (e) immunohistochemical stains (streptavidin-biotin method) in paraffin sections to detect cells that (i) express bcl-2 and bax proteins and (ii) undergo proliferation (Ki67+ cells). Results were expressed following morphometric analysis. RESULTS: Before hepatectomy, bcl-2 (protein or mRNA) levels were higher in jaundiced rats vs controls. Furthermore, bax (protein or mRNA) levels and apoptotic body index (ABI) were higher in cholestatic livers. After hepatectomy, there was an early decrease in the protein and mRNA levels of antiapoptotic gene bcl-2 and a late increase of proapoptotic gene bax and the ABI, compared to controls. Cell proliferation of hepatocytes was lower in group V (BDL + TLI) compared to that of groups II and IV (BDL). CONCLUSIONS: This study shows that apoptosis takes place in cholestatic livers with or without superimposed ischemia and may contribute in the impaired regenerative response observed in livers of jaundiced rats after partial hepatectomy.

Survival for 5 years after repeat liver resections and multimodality treatment for metastatic intestinal leiomyosarcoma: report of a case.

The liver is a common site of metastases from gastrointestinal or retroperitoneal leiomyosarcomas. Although repeat liver resections can prolong survival, to our knowledge, 5-year survival has never been achieved. We report the case of a woman who has survived for 5 years since her first liver resection, during which time five more resections have been performed, in combination with systemic chemotherapy and radiofrequency ablation.

The potential role of bcl-2 mRNA and protein exression in hepatocellular carcinomas.

BACKGROUND: The bcl-2 gene regulates programmed cell death by providing a survival advantage to rapidly proliferating cells. In several malignant tumors bcl-2 presence has been associated with favorable prognosis. In the liver, bcl-2 is expressed in bile ductular cells and tumors of biliary origin. This study investigates the expression of bcl-2 mRNA and protein in hepatocellular carcinomas (HCC). MATERIALS AND METHODS: The study comprised 35 primary HCC resected from 35 patients; 21 males and 14 females, aged from 43-59 years. The tumors were graded according to Edmondson criteria. In 28 cases HCC was developed on the background of cirrhotic liver. In 9 instances the patients received chemoembolization before surgery. The presence of bcl-2 mRNA was assessed on paraffin-embedded, 4 microm-thick sections, using a standard in situ hybridization method with a commercially available bcl-2 probe (Maxim Biotech, USA), while the streptavidin-biotin immunohistochemical technique was employed to detect bcl-2 protein expression using the monoclonal anti-bcl-2 antibody (DAKO, USA). The results were expressed as % of tumor-positive cells following morphometric analysis. RESULTS: The in situ hybridization study revealed bcl-2 mRNA expression in 25 out of 35 (70%) HCC. In addition, bcl-2 mRNA was detected in hyperplastic cholangioles within fibrous septae in the periphery of the tumors. Immunohistochemical staining failed to reveal any bcl-2 protein expression in tumor cells of HCC, whereas hyperplastic cholangioles of the fibrous septae, in the periphery of the tumors and intratumoral lymphocytes displayed a strong-positive cytoplasmic (perinuclear) stain. No significant correlations were recorded between bcl-2 mRNA expression and tumor histological pattern, grade, stage and the use of previous chemoembolization. CONCLUSION: In hepatocellular carcinomas, the bcl-2 gene is frequently present but its protein product is absent. This suggests a post-translational mechanism of bcl-2 protein degradation, indicating that bcl-2 does not play a substantial role in the progress of hepatocellular carcinoma.

Expresssion of bcl-2 oncoprotein in cases of acute and chronic viral hepatitis type B and type C: a clinicopathologic study.

The bcl-2 gene is involved in the regulation of programmed cell death by providing a survival advantage to rapidly proliferating cells. This study investigates bcl-2 protein expression in liver biopsies with acute or chronic viral hepatitis B (HBV) or C(HCV). The study comprised 60 liver biopsies with hepatitis B or C. These included 10 biopsies from cases with acute lobular hepatitis (ALH), and 50 with chronic hepatitis (CH). In addition, 10 liver biopsies were used as controls. In CH cases, HAI grade ranged from 3/18 to 15/18, and stage from 1 to 6 (6HBV/8HCV). Immunohistochemical bcl-2 expression was assessed using the streptavidin-biotin method and the presence of apoptotic cells was evaluated by TUNEL method. Immunohistochemical and in situ hybridization (TUNEL) results were expressed following morphometric analysis. In CH cases, bcl-2 was detected in portal and intralobular lymphocytes, and in cholangiolar epithelial cells of the interface area. In ALH and control cases, bcl-2 was expressed only in lymphocytes. Lymphocytic bcl-2 expression was correlated directly with categories A, C and D of HAI (P < 0.001), whereas the degree of fibrosis was reversibly correlated to bcl-2 expression. In conclusion, in cases of chronic hepatitis, bcl-2 expression in cholangioles of interface area suggests that this oncoprotein may be involved in regulation of growth of these epithelial cells.