Philippe Podevin

Rosiglitazone for Nonalcoholic Steatohepatitis: One-Year Results of the Randomized Placebo-Controlled Fatty Liver Improvement With Rosiglitazone Therapy (FLIRT) Trial

BACKGROUND & AIMS Nonalcoholic steatohepatitis (NASH) is a liver disease that complicates insulin-resistant states. This trial tested the efficacy and safety of rosiglitazone, an insulin-sensitizing agent, in patients with NASH. METHODS Sixty-three patients with histologically proven NASH were randomly assigned to receive rosiglitazone (4 mg/day for the first month and 8 mg/day thereafter; n = 32) or placebo (n = 31) for 1 year. Liver biopsy was performed at the end of treatment. End points were improvement in the histologic score of steatosis, normalization of serum transaminase levels, and improvement in necroinflammation and fibrosis. RESULTS More patients treated with rosiglitazone than receiving placebo had improved steatosis (47% vs 16%; P = .014) and normalized transaminase levels (38% vs 7%; P = .005), although only half of patients responded. There was no improvement in other histologic lesions, including fibrosis, and a composite score of activity, the nonalcoholic fatty liver disease activity score. Improvement of steatosis correlated with reduction of transaminase levels (r = 0.36; P < .005), improvement in insulin sensitivity (r = 0.34; P = .008), and increase in adiponectin levels (r = -0.54; P < .01) but not with weight variations. Independent predictors of response were rosiglitazone treatment, the absence of diabetes, and massive steatosis. Weight gain was the main adverse effect (mean gain of 1.5 kg in the rosiglitazone group vs -1 kg in the placebo group; P < .01), and painful swollen legs was the main reason for dose reduction/discontinuation. Serum hemoglobin level was slightly but significantly reduced. There was no hepatic toxicity. CONCLUSIONS In patients with NASH, rosiglitazone improves steatosis and transaminase levels despite weight gain, an effect related to an improvement in insulin sensitivity. However, there is no improvement in other parameters of liver injury.

Activation of the interferon-inducible protein kinase PKR by hepatocellular carcinoma derived-Hepatitis C virus core protein

Hepatitis C virus (HCV) is a major etiological agent of chronic liver disease and hepatocellular carcinoma (HCC). We demonstrate herewith that HCV core proteins encoded by sequences isolated from HCC tumor tissues, but not those derived from their non-tumor counterparts in the same liver, co-localise in vitro and in vivo and co-immunoprecipitate with PKR in hepatocytic Huh7 cells. We show that this association in fact augments the autophosphorylation of PKR and the phosphorylation of the translation initiation factor eIF2α, which are two markers of PKR activity. The present study therefore identifies a novel model of virus-cell interactions whereby a viral protein, the HCV core, activates PKR activity.

Defective inhibition of peripheral CD8+ T cell IL-2 production by anti-calcineurin drugs during acute liver allograft rejection.

Background. The aim of this study was to evaluate calcineurin activity and interleukin-2 (IL-2) expression by peripheral blood cells as a means of assessing the immune status of liver transplant recipients. Methods. Twenty-one patients were studied in a randomized study comparing cyclosporine and tacrolimus as the main immunosuppressive drug. Calcineurin activity was determined after separation of phosphorylated and dephosphorylated products of a calcineurin specific peptide substrate by high performance liquid chromatography (HPLC). Intracellular IL-2 expression was measured by flow cytometry. In 34 additional patients, intracellular IL-2 expression was prospectively measured. Results. Calcineurin activity fell after transplantation. Values were marginally higher in patients with acute rejection (P=0.059). The percentage of IL-2-producing T cells fell after transplantation. This percentage did not differ between patients with and without rejection. In contrast, the proportion of IL-2-producing CD8+ T cells was higher in patients with acute rejection than in patients free of acute rejection (P=0.003). Moreover, pretransplantation IL-2 expression by CD8+ T cells was higher in patients who subsequently developed acute rejection, suggesting that IL-2 production may be constitutively higher in those patients. The results obtained in the 34 additional patients confirmed these results. Conclusions. These data suggest that quantification of intracellular IL-2 in CD8+ T cells may be a useful index of immune status in liver transplant recipients. Preoperative IL-2 levels might serve to individually tailor the immunosuppressive regimen.

Interleukin-4 induces the activation and collagen production of cultured human intrahepatic fibroblasts via the STAT-6 pathway

Interleukin-4 (IL-4) is overexpressed in liver grafts in a context of severe recurrent hepatitis C, during which the development of fibrosis is dramatically accelerated. In this study, we examined the effects of IL-4 on the activation and collagen production of cultured human intrahepatic (myo)fibroblasts (hIHFs), and investigated the underlying mechanisms. The myofibroblastic nature of cells was evaluated morphologically using activation markers (smooth muscle α-actin, vimentin and prolyl 4-hydroxylase). Quiescent hIHFs were obtained by cell incubation in serum-free medium or cell culture on Matrigel. We first analyzed IL-4 receptor expression, STAT-6 activation by IL-4, and STAT-6 inhibition by an anti-IL-4 antibody or by STAT-6 small-interfering RNA (siRNA) transfection. We then focused on collagen production, using quantitative real-time PCR to analyze the effect of IL-4 on the mRNA expression of collagens I, III and IV, and on collagen levels in supernatants of hIHFs, using the Sircol collagen assay. hIHFs cultured in plastic wells appeared to be morphologically activated. The expression of activation markers was reduced by serum deprivation or culture on Matrigel, and restored by IL-4 incubation. The IL-4 receptor was expressed by hIHFs, and STAT-6 was activated following incubation with IL-4. Both anti-IL-4 antibody and STAT-6 siRNA transfection inhibited this activation. The treatment of hIHFs with IL-4 increased the mRNA expression of collagens I, III and IV (P<0.05) and elevated collagen levels in supernatants (P=0.01 vs untreated cells). Therefore, IL-4 exerts profibrotic effects by activating hIHFs and inducing collagen production and secretion. This effect requires IL4-R binding and STAT-6 activation. IL-4 may thus be involved in accelerated course of fibrogenesis during recurrent hepatitis C.

Interleukin-4 induces human hepatocyte apoptosis through a Fas-independent pathway

IL‐4 is overexpressed in liver grafts during severe recurrent hepatitis C and rejection. Hepatocyte apoptosis is involved in both these phenomena. We therefore examined the proapoptotic effect of IL‐4 on HepG2 cells and human hepatocytes in vitro, together with the underlying mechanisms. We first measured IL‐4 receptor expression, STAT6 activation by IL‐4, and STAT6 inhibition by an anti‐IL‐4 antibody or by STAT6 siRNA transfection. We then focused on the pathways involved in IL‐4‐mediated apoptosis and the role of STAT6 activation in apoptosis initiation. The IL‐4 receptor was expressed on both cell types, and STAT6 was activated by IL‐4. Both anti‐IL‐4 and STAT‐6 siRNA inhibited this activation. IL‐4 induced apoptosis of both HepG2 cells (P= 0.008 vs. untreated control) and human hepatocytes (P<0.001 vs. untreated control). IL‐4 reduced the mitochondrial membrane potential, activated Bid and Bax, and augmented caspase 3, 8, and 9 activity. STAT6 blockade inhibited IL‐4‐induced apoptosis. Expression of Fas and Fas ligand was unaffected when HepG2 cells and hepatocytes were cultured with IL‐4, and Fas/FasL pathway blockade failed to inhibit IL‐4‐induced apoptosis. These results show that IL‐4 induces apoptosis of human hepatocytes through IL‐4 receptor binding, STAT6 activation, decreased mitochondrial membrane potential, and increased caspase activation, independently of the Fas pathway. IL‐4 might thus contribute to the progression of severe liver graft damage.—Aoudjehane, L., Podevin, P., Scatton, O., Jaffray, P., Dusanter‐Fourt, I., Feldmann, G., Massault, P. P., Grira, L., Bringuier, A., Dousset, B., Chouzenoux, S., Soubrane, O., Calmus, Y., Conti, F. Interleukin‐4 induces human hepatocyte apoptosis through a Fas‐independent pathway. FASEB J. 21, 1433–1444 (2007)

CD25, CD28 and CD38 expression in peripheral blood lymphocytes as a tool to predict acute rejection after liver transplantation

Abstract:  Background/Aim:  The aim of this study was to determine whether the expression of CD25, CD28 and CD38 (which reflects the degree of T‐cell activation) by peripheral blood mononuclear cells constitutes a useful means of measuring the immune status of liver transplant recipients.

Quality Indicators for Colonoscopy Procedures: A Prospective Multicentre Method for Endoscopy Units

Background and Aims Healthcare professionals are required to conduct quality control of endoscopy procedures, and yet there is no standardised method for assessing quality. The topic of the present study was to validate the applicability of the procedure in daily practice, giving physicians the ability to define areas for continuous quality improvement. Methods In ten endoscopy units in France, 200 patients per centre undergoing colonoscopy were enrolled in the study. An evaluation was carried out based on a prospectively developed checklist of 10 quality-control indicators including five dependent upon and five independent of the colonoscopy procedure. Results Of the 2000 procedures, 30% were done at general hospitals, 20% at university hospitals, and 50% in private practices. The colonoscopies were carried out for a valid indication for 95.9% (range 92.5–100). Colon preparation was insufficient in 3.7% (range 1–10.5). Colonoscopies were successful in 95.3% (range 81–99). Adenoma detection rate was 0.31 (range 0.17–0.45) in successful colonoscopies. Conclusion This tool for evaluating the quality of colonoscopy procedures in healthcare units is based on standard endoscopy and patient criteria. It is an easy and feasible procedure giving the ability to detect suboptimal practice and differences between endoscopy-units. It will enable individual units to assess the quality of their colonoscopy techniques.

Fulminant autoimmune hepatitis after successful interferon treatment in an HIV-HCV co-infected patient

Summary Hepatitis C (HCV) treatment using interferon-α (IFN-α) and ribavirin is recommended in HIV/HCV co-infected patients to prevent liver cirrhosis and liver-related death. However, in addition to its antiviral activity, IFN is a pleiotropic cytokine able to synergistically amplify T-cell autoreactivity. Here, we report for the first time the induction of a subfulminant autoimmune hepatitis (AIH) after four months of a successful treatment of HCV-1b infection using peg-IFN and ribavirin, in a 48-year-old woman co-infected with HIV. Diagnosis was assessed according to the international AIH scoring system, including liver biopsy and confirmed by positive response to steroid challenge.

Elevated interleukin-4 expression in severe recurrent hepatitis C virus after liver transplantation.

Background. Chronic hepatitis C virus (HCV) is usually associated with high levels of hepatic interleukin (IL)-2 and low levels of IL-4 transcripts. HCV frequently recurs after liver transplantation, and its course is accelerated in this setting. We compared in situ expression of IL-2 and IL-4 in transplanted and nontransplanted patients with HCV. Methods. A total of 74 liver biopsy specimens were studied; 52 came from transplanted patients, 38 of whom were HCV-positive (17 mild and 21 severe cases of recurrent HCV) and 22 came from nontransplanted patients, 17 of whom were HCV-positive (7 mild and 10 severe cases of HCV). The expression of IL-2 and IL-4 mRNA and IL-4 protein was studied using the reverse transcriptase polymerase chain reaction and immunohistochemical methods, respectively. Results. IL-2 transcript levels were significantly higher in severe than in mild HCV in both liver graft recipients and nontransplanted patients. However, IL-2 levels were higher in nontransplanted than in transplanted patients. IL-4 transcripts and protein were preferentially detected in graft recipients with severe recurrent HCV. Conclusion. IL-4 expression is elevated in severe recurrent HCV and may play a role in the progression of hepatic lesions after liver transplantation.

Effects of bile acids on the humoral immune response: a mechanistic approach.

Whereas bile acids in excess depress the cell-mediated immune response, their effects on the humoral response have been little investigated. The aim of this study was to investigate the effects of bile acids on immunoglobulin production. Human peripheral blood mononuclear cells were stimulated for 5 days by Staphylococcus aureus Cowan I (SAC-I). Immunoglobulins were measured in the supernatants and cell lysates using ELISA. We found that bile acids inhibited IgM production in a dose-dependent manner. The inhibitory effects of 50 microM chenodeoxycholic acid (CDCA) and its glyco- and tauro-conjugates (62, 53 and 51%, respectively) were stronger than those of ursodeoxycholic acid (UDCA) and its conjugates (45, 40 and 34%, respectively). The inhibition of IgG production by CDCA and UDCA was weak (23 and 12%, respectively, at 50 microM). IgA production was not modified. The inhibition of intracellular IgM concentration paralleled that observed in the secreted compartment. By contrast, CDCA enhanced intracellular concentration of IgG. In the absence of significant necrosis or apoptosis, CDCA-mediated inhibition of SAC-I-induced IgM production was significantly correlated to the ability of the bile acid to inhibit cell proliferation (r=0.98; p<0.05). In conclusion, we showed that hydrophobic bile acids strongly depress the primary humoral response. This effect resulted from both an inhibition of cell proliferation, and to a lesser extent from a deficient exocytosis of immunoglobulins.