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 a-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 (Po0.05) and elevated collagen levels in supernatants (P ¼ 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.
Hepatitis E is the fifth known form of human viral hepatitis. Although not very common in our clinical practice, the incidence in Western countries is increasing. Infection with the hepatitis E virus (HEV) may be related to acute illness, liver failure, chronic hepatitis and cirrhosis. HEV itself is an RNA virus, with eight described genotypes (HEV 1–8), four of which more commonly affect humans and have, thus, been better studied. Besides liver manifestations, genotype 3 is also related to extra-hepatic manifestations, such as neurological, renal and rheumatological. Evolution to chronic disease occurs especially in patients who underwent transplantation, have hematological malignancies requiring chemotherapy, or have infection with the human immunodeficiency virus. The diagnosis may be difficult because of the low availability of tests and due to low sensibility and specificity. The acute form of illness does not have to be treated, but the chronic one does. We present here a literature review of hepatitis E and the relation between chronic hepatitis E and transplantation.
Anemia is common following liver transplantation. Because cyclosporine inhibits erythropoietin (Epo) production in experimental models, we investigated whether Epo production was impaired in liver transplant recipients receiving a cyclosporine-or tacrolimus-based immunosuppressive regimen. First, serum Epo levels were measured before and 1 year after transplantation in 35 liver transplant recipients. Second, serum Epo levels were compared in a large series of liver transplant recipients with stable graft and renal functions: 27 receiving a cyclosporine-based and 31 receiving a tacrolimusbased immunosuppressive regimen. A reference group was made up of 22 blood donors and 21 nontransplanted subjects with iron-deficiency anemia. Serum Epo levels were significantly lower after than before liver transplantation, especially in cyclosporine-treated patients. Serum Epo concentrations correlated with hematocrit values in both transplant recipients and control subjects. Using multiple linear regression models, the polynomial relationship between hematocrit and serum Epo values was similar to the control group in patients under tacrolimus, whereas Epo production was significantly reduced in patients under cyclosporine-based immunosuppression. Hematocrit values and the type of calcineurin inhibitor were the only parameters independently related to Epo levels. In conclusion, cyclosporine, but not tacrolimus, inhibits Epo production at the doses used in clinical practice.
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