Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023890 (cirrhosis)
 42,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The liver is continuously exposed to a large antigenic load that includes pathogens, toxins, tumor cells and dietary antigens. Amongst the hepatitis viruses, only hepatitis B virus (HBV) and hepatitis C virus (HCV) cause chronic hepatitis, which can progress to cirrhosis and hepatocellular carcinoma. Of the different antiviral defense systems employed by the tissue, apoptosis significantly contributes to the prevention of viral replication, dissemination, and persistence. Loss of tolerance to the liver autoantigens may result in autoimmune hepatitis (AIH). This review outlines the recent findings that highlight the role and mechanisms of apoptotic processes in the course of liver diseases. Among factors that contribute to liver pathology, we discuss the role of tumor necrosis factor (TNF)-alpha, HBx, ds-PKR, TRAIL, FasL, and IL-1alpha. Since TNF and FasL-induced hepatocyte apoptosis is implicated in a wide range of liver diseases, including viral hepatitis, alcoholic hepatitis, ischemia/reperfusion liver injury, and fulminant hepatic failure, these items will be discussed in greater detail in this review. We also highlight some recent discoveries that pave the way for the development of new therapeutic strategies by protecting hepatocytes (for example by employing Bcl-2, Bcl-XL or A1/Bfl-1, IAPs, or synthetic caspase inhibitors), or by the induction of apoptosis in stellate cells. The assessment of the severity of liver disease, as well as monitoring of patients with chronic liver disease, remains a major challenge in clinical hepatology practice. Therefore, a separate chapter is devoted to a novel cytochrome c-based method useful for the diagnosis and monitoring of fulminant hepatitis.
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PMID:Apoptosis in liver diseases--detection and therapeutic applications. 1625 9

Chronic bile duct ligation (BDL) is a useful model of cirrhosis. However, its parallel plasma and liver changes in levels of cytokines and nitric oxide (NO), involved in liver damage, remain unknown. The aims of this work were to quantify both the plasma and hepatic levels of five cytokines and NO in cirrhotic rats, 28 days after bile BDL, and to analyze their relationship with liver damage markers. One group of male Wistar rats was bile duct ligated and another group was sham operated, both groups were sacrificed 28 days after BDL. Plasma and liver cytokines, tumor necrosis factor-alpha (TNF-alpha), interleukin-6, -1beta, -10 (IL-6, -1beta, -10) and interferon-gamma (IFN-gamma), were measured by ELISA. Plasma and hepatic NO was determined as NO(2)(-)+NO(3)(-) by an enzymatic method. Alkaline phosphatase, gamma-glutamyl transpeptidase, alanine aminotransferase and bilirubins were determined in plasma. Collagen, lipid peroxidation and glycogen were quantified in liver. Two histopathological staining techniques were performed. BDL-induced cirrhosis was corroborated by the elevated liver damage markers and histopathological analysis. Chronic BDL significantly increased (P<0.05) most of plasma and hepatic cytokine levels and diminished the hepatic IFN-gamma amount. NO was increased in both tissues, but such change was only significant in plasma. Biliary cirrhosis produces interesting changes in plasma and hepatic levels of cytokines and NO. This finding in chronic BDL model in rats has not been previously described in both tissues for such cytokines and NO. Cytokines and NO imbalance favor establishment and perpetuation of cirrhosis.
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PMID:Chronic bile duct obstruction induces changes in plasma and hepatic levels of cytokines and nitric oxide in the rat. 1661 7

Liver fibrosis commonly occurs in patients with hepatitis C virus (HCV) infection as a consequence of the chronic liver damage, thus leading to the development of liver cirrhosis. When hepatic stellate cells (HSCs) become active, they play an essential role in liver fibrogenesis. In this study, interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), commonly elevated in chronic C hepatitis, stimulate the production of matrix metalloprotease-9 (MMP-9) by human hepatocytes at a transcriptional and translational level, but the addition of recombinant interferon-alpha2b (rIFN-alpha2b) hampers this effect. Furthermore, a human HSC line is activated in vitro by incubation with human MMP-9 in the presence of collagen I, and this effect is blocked by the MMP inhibitor BB94. A similar activation was observed when incubating HSCs with conditioned medium of hepatocytes previously stimulated with IL-1beta and TNF-alpha but not when using conditioned medium of hepatocytes costimulated with IL-1beta or TNF-alpha together with rIFN-alpha2b. In conclusion, our results show that hepatocytes stimulated by inflammatory cytokines participate in the activation of HSCs via MMP-9 production and that antiviral therapy modulates such activation.
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PMID:Antifibrogenic effect of IFN-alpha2b on hepatic stellate cell activation by human hepatocytes. 1668 58

Bacterial DNA (bactDNA) is present in blood and ascitic fluid (AF) in a third of patients with cirrhosis and ascites, but whether this phenomenon represents episodes of bacterial translocation (BT), strictly considered when culture of mesenteric lymph nodes (MLNs) are positive, remains unknown. This study assessed the relationship between bactDNA detection in biological fluids and MLNs and went on to investigate the local and systemic inflammatory status according to its presence. Cirrhosis was induced in rats by ingestion of CCL4. A subgroup of five animals with cirrhosis received norfloxacin (5 mg/kg/day) for 7 days. MLNs and ascitic and pleural fluids were collected at laparotomy and cultured; samples were collected for identification of bactDNA and measurement of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and nitric oxide (NO). BactDNA was detected in MLNs in 12 of 19 animals (63.1%), corresponding in seven cases to culture-positive MLNs, and in five to culture-negative MLNs. BactDNA was detected in biological fluids in 11 of 19 animals (57.9%), and in all cases the same bacteria spp. detected in samples was present in MLNs. BactDNA was not detected in any biological sample from animals receiving norfloxacin. Tumor necrosis factor alpha (TNF-alpha), IL-6, and NO were similar in culture-positive and culture-negative/bactDNA-positive samples, and significantly higher than those observed in animals with culture-negative/bactDNA-negative MLNs, animals with cirrhosis that were receiving norfloxacin, and controls. In conclusion, the presence of bactDNA in biological fluids in rats with cirrhosis constitutes a marker of BT, and it is associated with a marked inflammatory response, independent of the result of the culture.
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PMID:The detection of bacterial DNA in blood of rats with CCl4-induced cirrhosis with ascites represents episodes of bacterial translocation. 1694 89

Cirrhosis is the most important consequence of alcoholic liver disease for which liver transplantation is the only treatment option available. Transdifferentiation of hepatic stellate cells (HSC) to myofibroblastic cells (MF) is a central event in liver fibrogenesis, and understanding molecular mechanisms that underlie this cellular event provides pivotal insights into development of new therapeutic modalities for cirrhosis. To this end, the authors proposed several years ago that transdifferentiation of quiescent HSC to MF may be causally associated with transcriptional regulation known for adipocyte-preadipocytic fibroblast dedifferentiation. In support of this notion, the authors showed that adipogenic transcription factors and their downstream adipocyte specific genes are expressed abundantly in quiescent HSC and that this expression profile is lost in HM. Further, gain-of-function manipulations for adipogenic transcription factors such as peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and sterol regulatory element binding protein-1c have been shown to reverse culture-induced MF to quiescent HSC. The authors also demonstrated that tumor necrosis factor-alpha and Wnt, known mediators of anti-adipogenesis, also suppress the activity of PPAR-gamma and contribute to HSC-MF transdifferentiation. These results reinforce the concept of adipogenic regulation essential to the quiescent phenotype and the loss of such regulation underlying HSC-HM transdifferentiation. They also provide insights into the molecular basis for the use of PPAR-gamma agonists, which has been advocated for treatment of liver fibrosis.
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PMID:Anti-adipogenic regulation underlies hepatic stellate cell transdifferentiation. 1695 58

Most acute and chronic liver diseases are characterized by inflammatory processes with enhanced expression of various pro- and anti-inflammatory cytokines in the liver. These cytokines are the driving force of many inflammatory liver disorders often resulting in fibrosis and cirrhosis. Severe alcoholic hepatitis is a prototypic tumor necrosis factor-alpha (TNF-alpha)-associated disease. This knowledge has recently led to pilot studies with promising results investigating specific anti-TNF drugs such as infliximab or etanercept in the treatment of this disease, although a recently performed controlled French study did show a potential detrimental effect of this approach. Anti-TNF treatment strategies might also improve chronic hepatitis C infection as shown by one controlled trial using etanercept administered subcutaneously for 24 weeks. Furthermore, several case reports suggest that TNF-alpha neutralization is not harmful to patients chronically infected with this virus. In contrast, neutralization of TNF-alpha worsens and might even be associated with fatalities in chronic hepatitis B infection. Anti-inflammatory cytokines such as interleukin-10 (IL-10) have also been tried in patients with chronic liver diseases. Whereas IL-10 administered to patients with chronic hepatitis C virus infection shows indeed anti-inflammatory effects in the liver, it seems to act as a proviral agent thereby limiting its clinical utility. Another cytokine with major anti-inflammatory potential is the adipokine adiponectin, as its administration is beneficial in many experimental models of liver injury. Interference with cytokine pathways and/or administration of anti-inflammatory cytokines will be of major interest in the future therapy of many liver diseases.
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PMID:How to modulate inflammatory cytokines in liver diseases. 1703 2

We previously reported that fibroblast growth factor 2 (FGF2) facilitated the differentiation of transplanted bone marrow cells (BMCs) into hepatocytes. Our earlier study also demonstrated that administration of FGF2 in combination with bone marrow transplantation (BMT) synergistically activated tumor necrosis factor-alpha signaling and significantly improved liver function and prognosis more than BMT alone. However, the way that it affected the extracellular matrix remained unclear. Here, we investigated the effect of FGF2 treatment together with BMT on liver fibrosis in mice treated with carbon tetrachloride (CCl(4)). Transplantation of BMCs and concurrent treatment with FGF2 caused a statistically significant reduction in CCl(4)-induced liver fibrosis that was accompanied by strong expression of matrix metalloproteinase 9 as compared with FGF2-only treatment or BMT alone. Moreover, in this process, the proliferation of bone-marrow-derived cells was accelerated without causing apoptosis. Thus, the administration of FGF2 in combination with BMT synergistically improves CCl(4)-induced liver fibrosis in mice. This treatment has the potential of being an effective therapy for patients with liver cirrhosis.
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PMID:Administration of fibroblast growth factor 2 in combination with bone marrow transplantation synergistically improves carbon-tetrachloride-induced liver fibrosis in mice. 1709 19

Alcoholic liver disease (ALD) and its complications is still one of the most frequent causes of death in the Western world. Treatment modalities for both alcoholic steatohepatitis (ASH; the major inflammatory complication of ALD) and alcoholic liver cirrhosis are insufficient. Severe ASH is associated with a high mortality; although glucocorticoid treatment has been reported to improve survival, meta-analyses of clinical trials performed to date have failed to show a convincing benefit of such an approach. Most of the progress in understanding these diseases, especially ASH, has come from studies of cytokines. Various proinflammatory cytokines, such as tumor necrosis factor (TNF), have been proposed to have an important role in the pathophysiology of ALD and its complications. Pilot studies on the use of anti-TNF drugs, such as pentoxifylline or infliximab, in the treatment of ASH have now been performed with various levels of success. The treatment of patients with alcohol-related cirrhosis is mainly symptomatic and no therapies are currently available except orthotopic liver transplantation for end-stage liver disease. Independent of the stage of disease, abstinence from alcohol is the cornerstone of management. New treatment modalities for these diseases are eagerly awaited.
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PMID:Management strategies in alcoholic liver disease. 1720 86

Cytokines and chemokines are proteins that play a critical role in the regulation of immunity and inflammation in patients with chronic Hepatitis C. The aim of our study was to correlate serum cytokines, chemokines and apoptosis in non-treated chronic hepatitis C patients with various degrees of inflammation and fibrosis. We studied 778 patients: 59 had low Knodell fibrosis score and low Knodell histological activity index; 372 had mild fibrosis and low histological activity index; 270 had moderate fibrosis and moderate histological activity index; and, 77 had high fibrosis and high histological activity index on their biopsy. Serum cytokines, chemokines and apoptosis were measured by enzyme-linked-immunosorbent-assay. Multivariate analysis was employed for statistical purposes. A positive correlation was seen between the degree of inflammation and tumor necrosis factor-alpha (TNF-alpha) levels (r = 0.92) in non-cirrhotic patients and between interleukin 2 in all patients (r = 0.85). Interleukin-8 increased significantly at higher histological activity indices and continued to increase in patients with cirrhosis. Transforming growth factor-beta (TGF-beta) levels increased significantly with the severity of fibrosis, but decreased in cirrhotics. In conclusion, cytokines, chemokines and apoptosis levels reflect the progression of inflammation and fibrosis in hepatitis C infected patients, but their signatures differ.
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PMID:Cytokine--chemokine and apoptotic signatures in patients with hepatitis C. 1732 Jul 98

Obesity is a risk factor for hepatocellular carcinoma (HCC) complicated with alcoholic liver disease (ALD) and cryptogenic cirrhosis. Leptin is a 16-kDa antiobesity hormone secreted mainly by adipocytes. The role of leptin on alcohol-mediated effects in cell line is yet to be unraveled. Therefore, we investigated the effect of leptin against ethanol-elicited cytoxicity in human hepatoma cell lines (HepG2). HepG2 cells were treated with leptin (31.2 nM), ethanol (500 mM), ethanol+leptin and untreated cells served as control. 48 h after treatment, cell viability, apoptosis, TNF-alpha secretory response and oxidative damage were analysed. Our results suggest that leptin at a concentration of 31.2 nM prevents ethanol elicited cytotoxicity as evidenced by MTT and trypan blue dye exclusion assay. Leptin also inhibited ethanol-induced apoptosis, which was confirmed by [(3)H] thymidine uptake and cell cycle analysis using propidium iodide (PI) staining. Further, simultaneous leptin treatment along with ethanol showed protection against ethanol mediated cellular damage as indicated by significantly decreased levels of reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) and significantly increased levels of reactive nitrogen species (RNS), reduced glutathione (GSH) and elevated activities of superoxide dismutase (SOD) and catalase (CAT). In addition, leptin downregulated the secretion of tumor necrosis factor-alpha (TNF-alpha) by ethanol-induced HepG2 cells. Our results demonstrate that simultaneous leptin treatment along with ethanol could be useful in preventing the damage produced by ethanol, which might be of therapeutic interest.
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PMID:Mouse recombinant leptin protects human hepatoma HepG2 against apoptosis, TNF-alpha response and oxidative stress induced by the hepatotoxin-ethanol. 1754 59


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