Gady G. Katz

Tumor necrosis factor-α and transforming growth factor-β reflect severity of liver damage in primary biliary cirrhosis

Background and Aims The pathogenesis of primary biliary cirrhosis (PBC) is unknown. The role of cytokines such as tumor necrosis factor‐α (TNF‐α) and transforming growth factor‐β (ΤGF‐β), and the effect of ursodeoxycholic acid (UDCA) in modifying the cytokine environment in patients with PBC has remained largely unstudied. Our aims were to determine: (i) the relationship between serum levels of TNF‐α and TGF‐β and the severity of PBC; and (ii) the effects of UDCA therapy on TNF‐α and TGF‐β levels in patients with PBC.

Cytokines as predictors for sustained response and as markers for immunomodulation in patients with chronic hepatitis C.

OBJECTIVES (i) To characterize serum cytokine levels of tumor necrosis factor alpha (TNF alpha), interleukin 6 (IL 6), IL 8 and IL 12 in non-cirrhotic patients with chronic hepatitis C, (ii) to correlate the levels of these cytokines with the degree of the disease at the basal level, (iii) to correlate these levels with the response to therapy, (iv) to compare profiles of cytokines in monotherapy (MT) versus combination therapy (CT), and (v) to compare the immunomodulatory effects of MT versus CT. DESIGN AND METHODS 47 patients were enrolled in the study. The controls were 120 volunteers (recruited from students and staff) that did not present HCV RNA positive and were not known to suffer any other metabolic disease. Thirty patients formed the other group of controls, with alcoholic liver disease (ALD). Serum cytokine levels were assessed using enzyme-linked immunosorbent assay (ELISA). RESULTS The sustained responders (SRs) have basal values much lower than relapsed responders (RRs) and non-responders (NRs) regardless of the therapy. CONCLUSIONS Cytokines can be used as non-invasive markers for sustained response and as monitors for the outcome of therapy.

Kinetics of serum cytokines reflect changes in the severity of chronic hepatitis C presenting minimal fibrosis

Our aims were to measure the kinetics of serum tumour necrosis alpha (TNF‐α) and transforming growth factor beta (TGF‐β) levels as markers of progression of disease in nontreated chronic hepatitis C virus (HCV)‐infected patients with minimal or no fibrosis and minimal histology activity index (HAI) scores. Our study group consisted of 56 patients diagnosed with minimal (1) or no fibrosis (0) and minimal HAI (0–1) on their first biopsy as defined by Knodell and METAVIR scores. We compared their initial (entry of study) cytokine levels with a group of 103 HCV controls with minimal (0–1) to mild fibrosis (0–3) and mild HAI (5.5). Serum TNF‐α and TGF‐β levels were measured by enzyme‐linked‐immunosorbent‐assay. A significant difference was seen in TNF‐α levels at baseline in the study group vs. controls. Regardless of their HAI, there was a correlation between TGF‐β and degree of fibrosis. As shown by their biopsies, during the 3 years (from entry to follow up), many of the patients that initially had minimal fibrosis progressed to higher degree of fibrosis. This progression is paralleled by an increase in TGF‐β levels when comparing initial and follow‐up levels. In conclusion, serum TNF‐α reflects the progression of inflammation as seen in liver biopsies and TGF‐β reflects the degree of fibrosis in HCV patients.

CYP2E1-mediated modulation of valproic acid-induced hepatocytotoxicity

OBJECTIVES To determine the cytotoxicity of valproic acid (VPA) and its metabolite, 4-ene-valproic acid (4-ene-VPA) in human hepatoblastoma cells (Hep G2), and to study the modulatory effect of cytochrome P450 2E1 induction in this model. METHODS Cells were exposed to VPA or 4-ene-VPA in the presence of either ethanol (EtOH), or EtOH combined with disulphiram (DS). Some cells were exposed to alpha-fluoro-VPA or to alpha-fluoro-4-ene-VPA in the absence of CYP2E1 inducers. Apoptosis and necrosis were measured by analyzing 6000 cells per sample using transmission electron microscopy, while cytokine release and apoptosis were quantitated by ELISA. RESULTS VPA + EtOH increased VPA cytotoxicity. 4-ene-VPA + EtOH significantly increased toxicity, while DS + EtOH significantly reduced this toxicity. Alpha-fluorinated analogues reduced cytotoxicity compared to the corresponding VPA compounds. Neither VPA nor alpha-fluorinated VPA increased the release of IL-6 or TNF-alpha in media. A significant increase in the release of TNF-alpha was observed in cells exposed to 4-ene-VPA that further increased with EtOH exposure. CONCLUSIONS Cells exposed to 4-ene-VPA experience greater cytotoxicity than those treated with VPA. Cytochrome P450 2E1 inducers enhance toxicity in VPA-exposed cells, while alpha-fluorination of VPA diminishes cytotoxicity by directly interfering with the beta-oxidation of the 4-ene-VPA metabolite.

Predictors of sustained response to alpha interferon therapy in chronic hepatitis C.

BACKGROUND/AIMS The aim of this study was to determine the predictors for sustained response to alpha interferon therapy in a large population of patients with chronic hepatitis C, using multivariate analysis. METHODS Two hundred and ninety-six patients were included in four controlled trials of alpha interferon. Pretreatment serum HCV RNA levels were assessed by the branched DNA version 2.0 assay and HCV genotypes by the reverse hybridization assay (LiPA). RESULTS Sustained responses were observed in 37%, 14% and 6% of the patients with low, medium and high pretreatment serum HCV RNA levels, respectively (p<10(-4)). Sustained responses were observed in 5%, 4%, 32% and 27% of the patients with genotype 1a, 1b, 2a and 3a, respectively (p<10(-4)). The multivariate analysis showed that a non-transfusional source of HCV infection, low serum HCV RNA levels and HCV genotypes non-1 (2a or 3a) were independent factors associated with sustained response to interferon therapy. CONCLUSION Virological factors (low pretreatment serum HCV RNA level and HCV genotype non-1a and non-1b), when adjusted in a large population of patients, using improved technology, are the main independent predictors of sustained response to alpha interferon therapy.

Signaling for ethanol-induced apoptosis and repair in vitro.

OBJECTIVES To evaluate whether caspases are involved in ethanol (EtOH)-induced apoptosis and if polyenylphosphatidylcholine (PPC) affects apoptosis, in vitro in Hep G2 cells. METHODS Cells were treated with 100 mmol/L EtOH for 24 h and with 2 doses of 100 mmol/L EtOH (1/24 h) in the presence of absence of 20 mmol/L of PPC or 50 micromol/L caspase 3 inhibitor (IDN). Cells were analyzed for apoptosis by transmission electron microscopy (TEM) 6000 cells/treatment, DNA fragmentation by ELISA and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (T dt-mediated d-UTP) nick-end-labeling, TUNEL. RESULTS 100 mmol/L dose of EtOH resulted in 22 +/- 2.5% (p < 0.001) apoptosis (vs. control). Two consecutive doses of 100 mmol/L EtOH for 24 h each caused 36 +/- 3.0% (p < 0.001 vs. control and p < 0.05 vs. one dose). PPC significantly reduced apoptosis (vs. non exposed to PPC): 100 mmol/L -12 +/- 1.5% (p < 0.05) and 2 x 10(-)(0) mmol/L -20 +/- 2.0% (p < 0.001). Pretreatment with 50 micromol caspase inhibitor reduced EtOH-induced apoptosis in a similar proportion. CONCLUSIONS PPC downregulates EtOH-apoptosis by a mechanism similar to caspase inhibition.

Ethanol signals for apoptosis in cultured skin cells

Ethanol is commonly used in cosmetic and pharmaceutical preparations. To test whether ethanol may cause apoptosis in skin cells, we treated A431 epidermoid skin cells and neonatal human primary skin cells with different concentrations of ethanol, for different time periods. Ethanol was toxic to cells in both a dose- and time-dependent manner and increased the percentage of cells undergoing apoptosis. Treatment of cells with 40 and 100 mM ethanol increased release of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) into culture medium and increased its expression in cells. The TNF-alpha was toxic to A431 epidermoid skin cells at concentrations similar to those released by cells on exposure to ethanol. Ethanol-treated cells examined by electron microscopy showed organelle damage, condensed chromatin, and apoptotic bodies. Therefore, even at low concentrations, ethanol may induce apoptosis in skin cells by enhancing the effects of TNF-alpha.

Cytokine network in nonresponding chronic hepatitis C patients with genotype 1: role of triple therapy with interferon alpha, ribavirin, and ursodeoxycholate.

OBJECTIVE (i) to characterize the profile of tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), IL 10, Fas-ligand and transforming growth factor beta (TGF beta), chronic hepatitis C (HCV) patients with genotype 1; (ii) to determine the influence of triple therapy (TT) with interferon alpha (IFN alpha) + ribavirin + ursodeoxycholic acid on these cytokines and (iii) to establish the relationship between the pro-inflammatory cytokines and the outcome of treatment. DESIGN AND METHODS 22 patients infected with HCV-genotype 1 a/b and non responsive to IFN-alpha monotherapy were enrolled in the TT. The controls were 49 HCV naïve patients with genotype 1 a/b. Cytokine levels were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS The baseline TNF alpha values (pg/mL) in the sustained responders (SRs) (63+/-3) were significantly lower than non-responders (NRs) (140+/-16) (p < 0.001). Baseline Fas (ng/mL) levels were also lower in SRs (4.3+/-0.2) than NRs (5.4+/-0.4) (p < 0.05). CONCLUSIONS Fas and TNF alpha may be used as serological markers of inflammation and effectiveness of therapy.

Serum TNFA and TGF b levels in patients with chronic hepatitis C reflect the severity of the disease

SERUM TNFA AND TGF B LEVELS IN PATIENTS WITH CHRONIC HEPATITIS C REFLECT THE SEVERITY OF THE DISEASE. Manuela G. Neuman , Laurence M. Blendis, Daniel Sapir, Zamir Halpern, Neil H. Shear . Izabella M. Malkiewicz, Gady G. Katz, Jean-Pierre Benhamou, Patrick Marcellin, Fred Konikoff, Sunnybrook & Womens Call Health Sci Ctr, Toronto, ON. Canada; Toronto Gen Hasp, Toront o, ON, Canada; lchilov Hosp, Tel -Aviv, Israel; Hasp Beaujon, Paris. France.