D. H. Van Thiel

Pathogenesis of hepatitis B and C‐induced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is estimated to have an annual worldwide incidence of 0.25 to 1.2 million new cases per year. Both the prevalence and incidence of HCC vary markedly as a function of geography and the local prevalence of chronic viral hepatitis. Both chronic hepatitis B and chronic hepatitis C are recognized as risk factors for HCC. The prevalence of cirrhosis in individuals with HCC and chronic hepatitis B or C is reported to be 80.9% and 75.8%, respectively. HCC occurs at a lower rate in chronic viral hepatitis in the absence of cirrhosis. Moreover, hepatitis C virus (HCV) rather than hepatitis B virus (HBV) is associated with the majority of non‐cirrhotic cases of HCC. It is probable that the ongoing process of hepatocyte necrosis and liver cell renewal coupled with inflammation, which is characteristic of chronic viral hepatitis, causes not only nodular regeneration and cirrhosis but also progressive genomic errors in hepatocytes as well as unregulated growth and repair mechanisms leading to hepatocyte dysplasia and, in some cases, hepatic carcinoma. Current concepts concerning virus‐induced HCC are reported and discussed in the following review.

Proteins but not Nucleic Acids are Molecular Targets for the Free Radical Attack During Reoxygenation of Rat Hepatocytes

Isolated rat hepatocytes generate large amounts of reactive oxygen species and suffer a significant cell injury during postanoxic reoxygenation. The aim of this study was to determine whether oxidation of proteins and nucleic acids occurs during reoxygenation and whether their damage is related to the development of hepatocyte injury. Isolated perfused rat hepatocytes were exposed sequentially to 1 h of aerobic control, 2.5 h of anoxia, and 2 h of reoxygenation. Protein oxidation was determined by measuring the hepatocyte protein carbonyl content. DNA and RNA oxidation was assessed by measuring the 8-hydroxydeoxyguanosine and 8-hydroxyguanosine adducts, respectively. The control preanoxic carbonyl content was 6.48 +/- 1.03 nmol/mg protein. The preanoxic 8-8 hydroxydeoxyguanosine and 8-hydroxyguanosine levels were 4.76 +/- 1.22 pmol/ml and 14.19 +/- 2.17 pmol/ml, respectively. During anoxia, protein and nucleic acid oxidation did not change significantly. With reoxygenation, the protein carbonyl content increased significantly within 30 min, reaching a value of 10.25 +/- 1.58 nmol/mg. The nucleic acid oxidation level remained stable. Perfusion with 100 muM of during reoxygenation abolished protein oxidation. These results indicate that in rat hepatocytes during the early phase of reoxygenation: (1) the protein oxidation level increased significantly above the preanoxic aerobic values; (2) DNA and RNA oxidation does not appear to occur; and (3) free metal-mediated free radical reactions are involved in the oxidative protein damage.

The use of deferoxamine infusions to enhance the response rate to interferon-α treatment of chronic viral hepatitis B

Summary An individuals iron status may affect the response rate achieved with the use of interferon (IFN) as therapy for chronic viral hepatitis. A total of 27 patients with chronic hepatitis B viral infection, who had elevated serum ferritin levels, were randomized to receive either IFN 5 MU, three times weekly by subcutaneous injection alone (n= 14) or in combination with cycles of deferoxamine at a dose of 80 mg kg‐1 per cycle (n= 13) administered over 3 consecutive days, to reduce their iron and maintain a serum ferritin level less than 250 ng ml‐1. All deferoxamine‐treated patients were on a low iron‐containing diet. An IFN response was defined as a normalization of the serum alanine aminotransferase (ALT) level and seroconversion from hepatitis B e antigen (HBeAg) positivity to hepatitis B e antibody (HBeAb) positivity. The deferoxamine‐treated group experienced a reduction in their serum ferritin level to 226 ± 73 ng ml‐1 as a result of the deferoxamine treatment. Six of the 13 (46%) deferoxamine‐treated patients and two of the 14 (14%) control patients normalized their ALT levels. Seven of the 13 (54%) deferoxamine but only 14% of the IFN‐treated group seroconverted to HBeAb positivity. A greater rate of histological improvement and loss of hepatitis B virus (HBV) DNA was seen in the deferoxamine‐treated group. Two of the deferoxamine‐treated patients were treated only once, two were treated twice, seven were treated three times and two were treated four times to achieve a ferritin level below 250 ng ml‐1.

ALEX® (artificial liver for extracorporeal xenoassistance): A new bioreactor containing a porcine autologous biomatrix as hepatocyte support. Preliminary results in an ex vivo experimental model

Long-term maintenance of viability and expression of differentiated hepatocyte function is crucial for bioartificial liver support. We developed a new bioreactor design (ALEX®), associated with a new extracellular autologous hepatocyte biomatrix (Porcine Autologous Biomatrix - PBM) support. To test this new bioreactor, we compared it to a standard BAL (Bio-Artificial Liver) cartridge in a ex vivo model using human plasma added to bilirubin, ammonium and lidocaine. A pathology study was performed on both bioreactors. The results suggest that ALEX® allows a maximal contact between the perfusing plasma and the liver cells and a proper hepatocyte support by a cell-to-matrix attachment. ALEX® is a suitable cell support bioreactor, guaranteeing long-term maintenance of the metabolic activity of hepatocytes when compared to a standard BAL cartridge.

Relationship between the serum alanine aminotransferase level at the end of interferon treatment and histologic changes in wild‐type and precore mutant hepatitis B virus infections

Summary Unravelling the role of interferon (IFN) in the treatment of chronic hepatitis B is complicated by many factors. Several mutant forms of hepatitis B virus (HBV) have recently been discovered; the most common of these is the precore mutant, characterized by hepatitis Be antigen (HBeAg) negativity and hepatitis Be antibody (HBeAb) positivity in an individual with an active HBV infection. The aim of this study was to compare the response rate to IFN therapy in patients with wild‐type HBV infection and in individuals infected with the precore mutant. A second aim was to evaluate the role of an increased serum ferritin in terms of the IFN response rate in these two different types of HBV infection.

Modulation of endothelial cell inflammatory integrins and stress markers with rh‐factor VIIa in patients with advanced chronic hepatitis C

Summary. Individuals with chronic hepatitis C (CHC) progress to cirrhosis and hepatic cancer. Individuals with advanced CHC are coagulopathic and can manifest fibrinolysis. The coagulopathy is a consequence of hepatocytic dysfunction. The fibrinolysis represents a response to local endothelial cell injury, and is of a low‐grade. Based upon this hypothesis, the effect of the infusion of recombinant human factor VIIa (rh‐FVIIa) on endothelial cell inflammatory integrins and measures of endothelial stress were determined in 17 individuals with advanced CHC. Immediately prior to the infusion of rh‐FVIIa, the plasma levels of tissue factor (TF), Thrombomodulin (TM), human soluble ICAM‐1 (hs‐ICAM‐1), human soluble VCAM‐1 (hs‐VCAM‐1), human soluble L‐Selectin (hs‐L‐Selectin), the prothrombin time and the activated partial thromboplastin time were determined. The same parameters were assayed at 5, 10, 30, 120, 240 and 360 min after infusion. TF and TM levels were very high at baseline consistent with a vascular endothelial stress response. Similarly hs‐ICAM‐1, hs‐VCAM‐1 as well as L‐Selectin levels were increased. Thirty minutes after the infusion, a marked reduction in ICAM‐1 and VCAM‐1 and to a lesser degree L‐Selectin levels was observed. This reduction persisted for 360 min. No change in measures of fibrinolysis [plasminogen activator inhibitor‐1 (PAI‐1), total tissue factor pathway inhibitor (t‐TFPI), activated tissue factor pathway inhibitor (TFPIa), d‐dimers (DD), FSP and fibrinogen levels] occurred. In addition, no change in plasma Annexin‐V was observed. Based upon these data it can be concluded that: (1) rh‐FVIIa corrects the coagulopathy seen in advanced CHC; (2) reduces endothelial cell injury and/or stress as evidenced by the TF, TM, hs‐ICAM‐1 and hs‐VCAM‐1 levels in plasma; (3) these changes in coagulation occurred without inducing a propagated vascular thrombosis.