Early Stages Of Liver Fibrosis Research Articles

Insulin Resistance and Hyperinsulinemia in Patients with Chronic Liver Disease and Hepatocellular Carcinoma

ObjectivesTo investigate the role of insulin resistance (IR) and insulin plasma levels (IRI) in patients with chronic liver disease (CLD) and hepatocellular carcinoma (HCC).MethodsWe recruited the following patients: 125 with HCC, 128 with liver cirrhosis (LC) and 133 with chronic hepatitis C (CHC). IR was assessed by the HOMA-IR method. To define IR and hyperinsulinemia we selected as a cut-off level, the value of the 80th percentile for HOMA-IR (2.72) and IRI (11.18) in 113 healthy subjects.ResultsThe mean levels of HOMA-IR and IRI increase progressively among CHC (2.7 ± 2.9 and 11.5 ± 10.5, respectively), LC (5.4 ± 4.5 and 17.6 ± 11.2) and HCC (6.4 ± 9.8 and 18.2 ± 18.8). In the upper quintiles for HOMA-IR and IRI, the frequency of patients in the LC and HCC groups was twice as much in CHC cases. HCC with DM2 have the greatest percentage above the 80th percentile of HOMA-IR, their quintiles distribution is inverted and HOMA-IR mean values are significantly higher in comparison with HCC without DM2 cases.DiscussionOur study shows that the association between IR and CLD begins in the early stages of liver fibrosis. DM2 increases HOMA-IR and IRI mean levels in HCC patients and these metabolic factors could play a major role in the link between diabetes mellitus and hepatocarcinoma.

Pharmacological IKK2 inhibition blocks liver steatosis and initiation of non-alcoholic steatohepatitis

Background: Non-alcoholic-steatohepatitis (NASH) leading to fibrosis, end-stage cirrhosis and hepatocellular carcinoma is an increasing health problem in the Western world. Thus, the need for new therapeutic approaches is increasing. IKK2...

Noninvasive Assessment of Liver Fibrosis and Portal Hypertension With Transient Elastography

Hepatic fibrogenesis, the "final" common result of injury to the liver, is believed to be a critical factor leading to hepatic dysfunction and may be important in the pathogenesis of portal hypertension. Thus, accurate assessment of the degree of fibrosis is important clinically. For many years, examination of hepatic histopathology has been considered to be the "gold standard" tool used to assess fibrosis. However, liver biopsy is invasive, and in many instances not favored by patients or physicians. Thus, alternative approaches to measure liver fibrosis would be extremely attractive. To the extent that transient elastography is able to measure "liver stiffness," which is proportional to the degree of liver fibrosis, this technique holds great promise.

Abrogation of the Antifibrotic Effects of Natural Killer Cells/Interferon-γ Contributes to Alcohol Acceleration of Liver Fibrosis

Chronic alcohol drinking accelerates liver fibrosis in patients with viral hepatitis that cannot be fully explained by ethanol-enhanced liver damage. Here, we identified a novel mechanism by which alcohol accelerates liver fibrosis: inhibition of the antifibrotic effects of natural killer (NK) cells and interferon-gamma (IFN-gamma). Alcohol administration was achieved by feeding mice with a liquid diet containing 5% ethanol for 8 weeks. Liver fibrosis was induced by administration of carbon tetrachloride (CCl(4)) for 2 weeks. Hepatic stellate cells (HSCs) were also isolated and cultured for in vitro studies. CCl(4) treatment induced greater fibrosis and less apoptosis of HSCs in ethanol-fed mice compared with pair-fed mice. Polyinosinic-polycytidylic acid (Poly I:C) or IFN-gamma treatment inhibited liver fibrosis in pair-fed but not in ethanol-fed mice. Poly I:C activation of NK cell cytotoxicity against HSCs was attenuated in ethanol-fed mice compared with pair-fed mice, which was due to reduced natural killer group 2 member D (NKG2D), tumor necrosis factor-related apoptosis-inducing ligand, and IFN-gamma expression on NK cells from ethanol-fed mice. In vitro, HSCs from ethanol-fed mice were resistant to IFN-gamma-induced cell cycle arrest and apoptosis compared with pair-fed mice. Such resistance was due to diminished IFN-gamma activation of signal transducer and activator of transcription 1 (STAT1) in HSCs from ethanol-fed mice caused by the induction of suppressors of cytokine signaling proteins and the production of oxidative stress. Finally, HSCs from ethanol-fed mice were resistant to NK cell killing, which can be reversed by transforming growth factor-beta1 (TGF-beta1) neutralizing antibody. Chronic ethanol consumption attenuates the antifibrotic effects of NK/IFN-gamma/STAT1 in the liver, representing new and different therapeutic targets with which to treat alcoholic liver fibrosis.

Differential regulated expression of keratinocyte growth factor and its receptor in experimental and human liver fibrosis

Background and aim Immunomodulatory and protective properties have been identified for the keratinocyte growth factor (KGF). For hepatocytes, pro-proliferative and anti-apoptotic effects of this growth factor have been reported in vitro. This study was designed to characterize a putative role of KGF in observed histomorphological changes in both, human and experimental liver fibrosis. Methods Liver fibrosis and cirrhosis was induced in rats by repetitive exposure to phenobarbitone and increasing doses of carbon tetrachloride. Human samples were obtained from patients undergoing surgery for partial hepatectomy or transplantation. Organ samples were scored for inflammation and morphological changes. Expression of KGF and its receptor (KGFR) mRNA was quantified by real-time RT-PCR. Protein expression and receptor phosphorylation was determined by Western blot analysis. In-situ hybridization and immunohistochemistry were utilized to determine distribution of KGF and KGFR in the liver. Results Expression of KGF was significantly increased in damaged liver tissue in correlation to the degree of fibrosis, whereas expression of the receptor was up-regulated in early stages of liver fibrosis and down-regulated in cirrhotic organs. Protein expression of this growth factor and its receptor correlated with the alterations in mRNA. KGF expression was restricted to mesenchymal cells, whereas expression of KGFR was detected on hepatocytes only. Conclusion The expression of KGF and KGFR is differentially and significantly regulated in damaged liver tissue. This growth factor might therefore not only contribute to morphological alterations but also regeneration of liver parenchyma most likely mediated by indirect mechanisms of action.

Molecular profiling of early stage liver fibrosis in patients with chronic hepatitis C virus infection

The molecular mechanisms of acute hepatitis C virus (HCV) infection, end-stage hepatitis (cirrhosis), and hepatocellular carcinoma have been extensively studied, but little is known of the changes in liver gene expression during the early stages of liver fibrosis associated with chronic HCV infection, that is, the transition from normal liver (NL) of uninfected patients to the first stage of liver fibrosis (F1-CH-C). To obtain insight into the molecular pathogenesis of F1-CH-C, we used real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to study the mRNA expression of 240 selected genes in liver tissue with F1-CH-C, in comparison with NL. The expression of 54 (22.5%) of the 240 genes was significantly different between F1-CH-C and NL; 46 genes were upregulated and 8 were downregulated in F1-CH-C. The most noteworthy changes in gene expression mainly affected the transcriptional network regulated by interferons (IFNs), including both IFN-α/β-inducible genes ( STAT1, STAT2, ISGF3G/IRF9, IFI27, G1P3, G1P2, OAS2, MX1) and IFN-γ-inducible genes ( CXCL9, CXCL10, CXCL11). Interesting, upregulation of IFN-α/β-inducible genes (but not IFN-γ-inducible genes) was independent of histological scores (grade and stage of fibrosis) and HCV characteristics (hepatic HCV mRNA levels and the HCV genotype), and was specific to HCV (as compared to hepatitis B virus (HBV)). Other genes dysregulated in F1-CH-C, albeit less markedly than IFN-α/β- and IFN-γ-inducible genes, were mainly involved in the activation of lymphocytes infiltrating the liver ( IFNG, TNF, CXCL6, IL6, CCL8, CXCR3, CXCR4, CCR2), cell proliferation ( p16/CDKN2A, MKI67, p14/ARF), extracellular matrix remodeling ( MMP9, ITGA2), lymphangiogenesis ( XLKD1/LYVE), oxidative stress ( CYP2E1), and cytoskeleton microtubule organization ( STMN2/SCG10). Thus, a limited number of signaling pathways, and particularly the transcriptional network regulated by interferons, are dysregulated in the first stage of HCV-induced liver fibrosis. Some of the genes identified here could form the basis for new approaches aimed at refining IFN-based therapies for chronic HCV infection.

Doppler measurements: a surrogate marker of liver fibrosis?

The potential diagnostic value of performing Doppler measurements of liver vasculature to assess early stages of liver fibrosis has not been established. Due to the potential clinical impact, this study focused on the correlation between Doppler measurements and histologically proven liver fibrosis. Forty-three consecutive patients with chronic viral hepatitis (79% hepatitis C) were enrolled. At the time of liver biopsy, two independent investigators measured maximum and mean blood flow velocity, resistance indices, vessel diameter and blood flow volume in the portal vein, hepatic artery and hepatic veins. All measurements were taken in triplicate. The mean values were correlated to the degree of liver fibrosis using the Ludwig score. Sixty-seven per cent of the patients in our study group had no or only mild fibrosis (Ludwig score stage I or II). Thirty-three per cent showed progressive fibrosis or cirrhosis (Ludwig score stage III or IV). There was a large overlap in the Doppler measurements and findings between the various disease stages. No significant changes of Doppler parameters were detected, even between patients with no or mild fibrosis and patients with severe fibrosis (Ludwig score stage III or IV). Doppler measurements of the portal vein, hepatic artery and hepatic vein(s) are not a valid surrogate marker of liver fibrosis. Nor are Doppler measurements a useful method to estimate the degree of liver fibrosis.

Functional state of the hematopoietic system in different stages of CCl4-induced liver fibrosis in mice

The state of hemopoietic system at different stages of CCL4-induced liver fibrosis in mice and its reaction to stimuli was examined. At early stages of liver fibrosis (2 weeks of CCL4-administration) we observed a disinhibition of granulo-monocytopoiesis. This is manifested in an increase of the number of immature granulocytes, monocytes/macrophages and CFU-GM in the bone marrow. After 24 h of zymosan injection in this stage an increase of both bone marrow CFU-GM and CFU-E, and the rate of serum colony stimulating activity (CSA) occurred. On the contrary, in advanced liver fibrosis (16 weeks of CCL4 administration), the rate of both granulo-monocytopoiesis and erythropoiesis were decreased as compared with the preceding stage of the process and the response to zymosan became perverted: the number of CFU-GM was paradoxically decreased, while the number of CFU-E remained practically unchanged. The rate of serum CSA increased very poorly too. Thus, in advanced liver fibrosis the hemopoietic system is functionally defective and this factor may be important in development of fibrotic process in the liver.

Cellular distribution of transforming growth factor-beta 1 and procollagen types I, III, and IV transcripts in carbon tetrachloride-induced rat liver fibrosis.

The cellular distribution and temporal expression of transcripts from transforming growth factor-beta 1 (TGF-beta 1) and procollagen alpha 1(I), alpha 1(III), and alpha 1(IV) genes were studied in carbon tetrachloride (CCl4)-induced rat liver fibrosis by using in situ hybridization technique. During the fibrotic process, TGF-beta 1 and procollagen genes were similarly and predominantly expressed in Desmin-positive perisinusoidal cells (e.g., fat-storing cells and myofibroblasts) and fibroblasts and their expression continued to be higher than those observed in control rats. These transcripts were also observed in inflammatory cells mainly granulocytes and macrophage-like cells at the early stages of liver fibrosis. The production of extracellular matrix along small blood vessels and fibrous septa coincided with the expression of these genes. Expression of TGF-beta 1 and procollagen genes were not detected in hepatocytes throughout the experiment. No significant differences in cellular distribution or time course of gene expression among procollagen alpha 1(I), alpha 1(III), and alpha 1(IV) were observed. Desmin-positive perisinusoidal cells and fibroblasts appeared to play the principal role in synthesis of collagens in CCl4-induced hepatic fibrosis. The simultaneous expression of TGF-beta 1 and procollagen genes in mesenchymal cells, including Desmin-positive perisinusoidal cells, during hepatic fibrosis suggests the possibility that TGF-beta 1 may have an important role in the production of fibrosis.