Circulating microRNAs: promising candidates serving as novel biomarkers of acute hepatitis

Acute liver failure as life threatening condition comprises a difficult diagnostic situation to evaluate potential outcomes and therapeutic options. Thus, prognostic indicators are urgently needed for evaluation of progression of liver injury, clinical outcome, prognosis, and for therapeutic response. Recently, circulating microRNA, in particular miR-122, was described as a potential biomarker of acute liver injury after intoxication of mice. Circulating microRNA (miRNA) molecules are very stable and RNase-resistant due to protein aggregation and vesicle enclosure. Since miRNA species are known to be associated with chronic liver damage or with liver cancer, circulating miRNA patterns are suggested to serve also as reporters for progression of acute liver failure. miRNA profiling analyses using PCR arrays or next generation sequencing, may achieve identification of miRNA species that are linked to the rapid progression of acute liver injury, to the outcome of liver failure, or to the therapeutic response. Therefore, circulating miRNAs are promising, non-invasive biomarkers of future diagnostic approaches. However, normalisation of circulating miRNA levels is essential and further standardisation of miRNA quantification assays is needed

SPARC expression is associated with hepatic injury in rodents and humans with non-alcoholic fatty liver disease

Mechanisms that control progression from simple steatosis to steato-hepatitis and fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) are unknown. SPARC, a secreted matricellular protein, is over-expressed in the liver under chronic injury. Contribution of SPARC accumulation to disease severity is largely unknown in NAFLD. We assessed the hypothesis that SPARC is increased in livers with more necrosis and inflammation and could be associated with more fibrosis. qrt-PCR, immunohistochemistry, and ELISA were employed to localize and quantify changes in SPARC in 62 morbidly obese patients with NAFLD/NASH and in a mouse model of diet-induced-NASH. Results were correlated with the severity of NAFLD/NASH. In obese patients 2 subgroups were identified with either high SPARC expression (n = 16) or low SPARC expression (n = 46) in the liver, with a cutoff of 1.2 fold expression. High expression of SPARC paralleled hepatocellular damage and increased mRNA expression of pro-fibrogenic factors in the liver. In line with these findings, in the NASH animal model SPARC knockout mice were protected from inflammatory injury, and showed less inflammation and fibrosis. Hepatic SPARC expression is associated with liver injury and fibrogenic processes in NAFLD. SPARC has potential as preventive or therapeutic target in NAFLD patients.Fil: Mazzolini Rizzo, Guillermo Daniel. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Atorrasagasti, María Catalina. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Onorato, Agostina Mariana. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Peixoto, Estanislao. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Schlattjan, Martin. Universitat Essen; AlemaniaFil: Sowa, Jan Peter. Universitat Essen; AlemaniaFil: Sydor, Svenja. Universitat Essen; AlemaniaFil: Gerken, Guido. Universitat Essen; AlemaniaFil: Canbay, Ali. Universitat Essen; Alemani

Evaluation of Biomarkers of NAFLD in a Cohort of Morbidly Obese Patients

Hepatocyte apoptosis is a key event in nonalcoholic fatty liver disease (NAFLD), and serum apoptotic markers are emerging as surrogate markers for NAFLD. We studied the role of caspase-cleaved cytokeratin18 in the diagnosis of fibrosis in a cohort of 127 morbidly obese patients and also performed a review of the literature biomarkers of NAFLD and fibrosis. Here, we found that cleaved caspase 18 correlated with liver steatosis and liver injury as assessed by serum transaminase levels. Furthermore, hepatocyte apoptosis as assessed by cleaved CK18 and TUNEL staining correlated with the extent of fibrosis as assessed by Sirius Red staining and serum hyaluronic acid. These results underscore the important role of hepatocyte apoptosis in the pathogenesis of fibrosis in NAFLD, which led to the utilization of surrogate markers for apoptosis in the noninvasive diagnosis of NAFLD. We furthermore reviewed current literature of biomarkers of NAFLD and fibrosis

NLRP3 inflammasome activation is required for fibrosis development in NAFLD

NLR inflammasomes, caspase 1 activation platforms critical for processing key pro-inflammatory cytokines, have been implicated in the development of nonalcoholic fatty liver disease (NAFLD). As the direct role of the NLRP3 inflammasome remains unclear, we tested effects of persistent NLRP3 activation as a contributor to NAFLD development and, in particular, as a modulator of progression from benign hepatic steatosis to steatohepatitis during diet-induced NAFLD. Gain of function tamoxifen-inducible Nlrp3 knock-in mice allowing for in vivo temporal control of NLRP3 activation and loss of function Nlrp3 knockout mice were placed on short-term choline-deficient amino acid-defined (CDAA) diet, to induce isolated hepatic steatosis or long-term CDAA exposure, to induce severe steatohepatitis and fibrosis, respectively. Expression of NLRP3 associated proteins was assessed in liver biopsies of a well-characterized group of patients with the full spectrum of NAFLD. Nlrp3−/− mice were protected from long-term feeding CDAA-induced hepatomegaly, liver injury, and infiltration of activated macrophages. More importantly, Nlrp3−/− mice showed marked protection from CDAA-induced liver fibrosis. After 4 weeks on CDAA diet, wild-type (WT) animals showed isolated hepatic steatosis while Nlrp3 knock-in mice showed severe liver inflammation, with increased infiltration of activated macrophages and early signs of liver fibrosis. In the liver samples of patients with NAFLD, inflammasome components were significantly increased in those patients with nonalcoholic steatohepatitis (NASH) when compared to those with non-NASH NAFLD with mRNA levels of pro-IL1 beta correlated to levels of COL1A1. Our study uncovers a crucial role for the NLRP3 inflammasome in the development of NAFLD. These findings may lead to novel therapeutic strategies aimed at halting the progression of hepatic steatosis to the more severe forms of this disease.Fil: Wree, Alexander. University of California at San Diego; Estados Unidos. University Hospital Essen; AlemaniaFil: McGeough, Matthew D.. University of California at San Diego; Estados UnidosFil: Peña, Carla A.. University of California at San Diego; Estados UnidosFil: Schlattjan, Martin. University Hospital Essen; AlemaniaFil: Li, Hongying. University of California at San Diego; Estados UnidosFil: Inzaugarat, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; ArgentinaFil: Messer, Karen. University of California at San Diego; Estados UnidosFil: Canbay, Ali. University Hospital Essen; AlemaniaFil: Hoffman, Hal M.. University of California at San Diego; Estados Unidos. Ludwig Institute of Cancer Research; Estados UnidosFil: Feldstein, Ariel E.. University of California at San Diego; Estados Unido

Ablation of C-type natriuretic peptide/cGMP signaling in fibroblasts exacerbates adverse cardiac remodeling in mice

Excessive activation of cardiac fibroblasts (CFs) in response to injury provokes cardiac fibrosis, stiffness, and failure. The local mediators counter-regulating this response remain unclear. Exogenous C-type natriuretic peptide (CNP) exerted antifibrotic effects in preclinical models. To unravel the role of the endogenous hormone, we generated mice with fibroblast-restricted deletion (KO) of guanylyl cyclase-B (GC-B), the cGMP-synthesizing CNP receptor.CNP activated GC-B/cGMP signaling in human and murine CFs, preventing proliferative and promigratory effects of AngiotensinII (AngII) and TGF-β. Fibroblast-specific GC-B-KO mice showed enhanced fibrosis in response to AngII infusions. Moreover, after two weeks of mild pressure-overload induced by transverse aortic constriction (TAC), such KO mice had augmented cardiac fibrosis and hypertrophy, together with systolic and diastolic contractile dysfunction. This was associated with increased expression of the profibrotic genes collagen I, III and periostin. Notably, such responses to AngII and TAC were greater in female as compared to male KO mice. Enhanced AngII-induced CNP expression in female hearts and augmented GC-B expression and activity in female CFs may contribute to this sex disparity.The results show that paracrine CNP signaling in CFs has antifibrotic and antihypertrophic effects. The CNP/GC-B/cGMP pathway might be a target for therapies combating pathological cardiac remodeling

Hepatocyte KLF6 expression affects FXR signalling and the clinical course of primary sclerosing cholangitis

Background & Aims: Primary sclerosing cholangitis (PSC) is characterized by chronic cholestasis and inflammation, which promotes cirrhosis and an increased risk of cholangiocellular carcinoma (CCA). The transcription factor Krueppel-like-factor-6 (KLF6) is a mediator of liver regeneration, steatosis, and hepatocellular carcinoma (HCC), but no data are yet available on its potential role in cholestasis. Here, we aimed to identify the impact of hepatic KLF6 expression on cholestatic liver injury and PSC and identify potential effects on farnesoid-X-receptor (FXR) signalling. Methods: Hepatocellular KLF6 expression was quantified by immunohistochemistry (IHC) in liver biopsies of PSC patients and correlated with serum parameters and clinical outcome. Liver injury was analysed in hepatocyte-specific Klf6-knockout mice following bile duct ligation (BDL). Chromatin-immunoprecipitation-assays (ChIP) and KLF6-overexpressing HepG2 cells were used to analyse the interaction of KLF6 and FXR target genes such as NR0B2. Results: Based on IHC, PSC patients could be subdivided into two groups showing either low (80%) hepatocellular KLF6 expression. In patients with high KLF6 expression, we observed a superior survival in Kaplan-Meier analysis. Klf6-knockout mice showed reduced hepatic necrosis following BDL when compared to controls. KLF6 suppressed NR0B2 expression in HepG2 cells mediated through binding of KLF6 to the NR0B2 promoter region. Conclusion: Here, we show an association between KLF6 expression and the clinical course and overall survival in PSC patients. Mechanistically, we identified a direct interaction of KLF6 with the FXR target gene NR0B2

UP-REGULATION OF STRESS-INDUCED LIGANDS IS ASSOCIATED WITH ENHANCED HEPATOCYTE APOPTOSIS AND FIBROSIS IN PATIENTS WITH NASH

60th Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases -- OCT 30-NOV 03, 2009 -- Boston, MAWOS: 000270456001033…Amer Assoc Study Liver Di

SPARC expression is associated with hepatic injury in rodents and humans with non-alcoholic fatty liver disease

Abstract Mechanisms that control progression from simple steatosis to steato-hepatitis and fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) are unknown. SPARC, a secreted matricellular protein, is over-expressed in the liver under chronic injury. Contribution of SPARC accumulation to disease severity is largely unknown in NAFLD. We assessed the hypothesis that SPARC is increased in livers with more necrosis and inflammation and could be associated with more fibrosis. qrt-PCR, immunohistochemistry, and ELISA were employed to localize and quantify changes in SPARC in 62 morbidly obese patients with NAFLD/NASH and in a mouse model of diet-induced-NASH. Results were correlated with the severity of NAFLD/NASH. In obese patients 2 subgroups were identified with either high SPARC expression (n = 16) or low SPARC expression (n = 46) in the liver, with a cutoff of 1.2 fold expression. High expression of SPARC paralleled hepatocellular damage and increased mRNA expression of pro-fibrogenic factors in the liver. In line with these findings, in the NASH animal model SPARC knockout mice were protected from inflammatory injury, and showed less inflammation and fibrosis. Hepatic SPARC expression is associated with liver injury and fibrogenic processes in NAFLD. SPARC has potential as preventive or therapeutic target in NAFLD patients