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

Chronic hepatitis B virus (HBV) infection can cause severe liver disease, including cirrhosis and hepatocellular carcinoma. Lamivudine is a relatively recent alternative to alpha interferon for the treatment of HBV infection, but unfortunately, resistance to lamivudine commonly develops during monotherapy. Lamivudine-resistant HBV mutants display specific mutations in the YMDD (tyrosine, methionine, aspartate, aspartate) motif of the viral polymerase (reverse transcriptase [rt]), which is the catalytic site of the enzyme, i.e., methionine 204 to isoleucine (rtM204I) or valine (rtM204V). The latter mutation is often accompanied by a compensatory leucine-to-methionine change at codon 180 (rtL180M). In the present study, a novel sequencing method, pyrosequencing, was applied to the detection of lamivudine resistance mutations and was compared with direct Sanger sequencing. The new pyrosequencing method had advantages in terms of throughput. Experiments with mixtures of wild-type and resistant viruses indicated that pyrosequencing can detect minor sequence variants in heterogeneous virus populations. The new pyrosequencing method was evaluated with a small number of patient samples, and the results showed that the method could be a useful tool for the detection of lamivudine resistance in the clinical setting.
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PMID:Pyrosequencing for detection of lamivudine-resistant hepatitis B virus. 1547 42

Endothelin-1 is known to be implicated in the pathogenesis of hepatobiliary diseases such as cirrhosis, especially in portal hypertension. This study aimed to investigate the effects of ursodeoxycholic acid on endothelin-1 production in human endothelial cells. The effects of ursodeoxycholic acid and its conjugates (tauroursodeoxycholic and glycoursodeoxycholic acids) on endothelin-1 production as well as nitric oxide (NO) in human umbilical vein endothelial cells (HUVECs) were examined. The production of endothelin-1 and nitric oxide in culture medium was measured using enzyme-linked immunosorbent assay (ELISA) and the Griess method, respectively. Endothelin-1 and endothelial nitric oxide synthase (eNOS) mRNA expression were investigated by real-time quantitative reverse transcriptase/polymerase chain reaction (RT-PCR). Ursodeoxycholic acid (30-1000 microM) inhibited endothelin-1 production in a concentration-dependent manner, and ursodeoxycholic acid at concentrations higher than 300 microM increased nitric oxide production in culture medium. The conjugates of ursodeoxycholic acid also increased nitric oxide production and decreased endothelin-1 production, which was less effective than ursodeoxycholic acid. N-nitro-L-arginine-mythel-ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, suppressed the ursodeoxycholic acid-induced nitric oxide production, but it did not antagonize the inhibitory effects of ursodeoxycholic acid on endothelin-1 production. Ursodeoxycholic acid also induced a concentration-dependent decrease in endothelin-1 mRNA expression without significant changes in eNOS mRNA expression. These results provide novel evidence that ursodeoxycholic acid inhibits endothelin-1 production in human endothelial cells, but nitric oxide is not responsible for the inhibitory effect of ursodeoxycholic acid on endothelin-1. Thus, ursodeoxycholic acid therapy may prevent the development of several pathogenesis such as portal hypertension observed in patients with cirrhosis due to the improvement of endothelial function.
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PMID:Ursodeoxycholic acid inhibits endothelin-1 production in human vascular endothelial cells. 1555 38

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-alpha/beta-inducible genes (STAT1, STAT2, ISGF3G/IRF9, IFI27, G1P3, G1P2, OAS2, MX1) and IFN-gamma-inducible genes (CXCL9, CXCL10, CXCL11). Interesting, upregulation of IFN-alpha/beta-inducible genes (but not IFN-gamma-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-alpha/beta- and IFN-gamma-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.
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PMID:Molecular profiling of early stage liver fibrosis in patients with chronic hepatitis C virus infection. 1566 Nov 46

Infection with hepatitis B virus (HBV) leads to a wide spectrum of clinical presentations ranging from an asymptomatic carrier state to self-limited acute or fulminant hepatitis to chronic hepatitis with progression to cirrhosis and hepatocellular carcinoma (HCC). Infection with HBV is one of the most common viral diseases affecting man. Both viral factors as well as the host immune response have been implicated in the pathogenesis and clinical outcome of HBV infection. Evidence has been accumulating that HBV mutants are associated with certain clinical disease manifestations, may affect the natural course of the infection and confer resistance to antivirals. Naturally occurring mutations have been identified in the structural and non-structural genes as well as regulatory elements of the virus. The best characterized mutants comprise the pre-core (pre-C) stop codon mutation resulting in a loss of hepatitis B e antigen (HBeAg), defined clusters of mutations in the core promotor resulting in enhanced viral replication and mutations in the hepatitis B core and surface antigens (HBcAg and HBsAg) altering the antigenicity of the virus. More recently, several mutations in the reverse transcriptase/polymerase gene have been identified conferring resistance to antivirals used for the treatment of chronic hepatitis B. In this review, we will focus on the biological phenotype of HBV genetic variants and discuss their clinical relevance for the pathogenesis of HBV-induced liver disease.
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PMID:Genetic variants of hepatitis B virus and their clinical relevance. 1575 49

There is increasing concern that patients with chronic HIV infection may be at increased risk of nonalcoholic fatty liver disease (NAFLD), which can evolve into nonalcoholic steatohepatitis (NASH) and cirrhosis. Multiple factors have been hypothesized to be necessary for the development and progression of this condition. Potential risk factors, which tend to accumulate in the HIV-positive population, include metabolic derangements, chronic inflammation, hepatitis coinfection, and treatment with certain nucleoside reverse transcriptase inhibitors (NRTIs). HIV-associated conditions such as hyperlactatemia and lipodystrophy frequently overlap with fatty liver disease. The cornerstone of management of HIV-associated fatty liver disease is currently to treat the predominant underlying condition. There is a need for more epidemiologic data to better define the role of comorbidities and drugs in the development of NAFLD. Further work is also needed to elucidate the pathogenesis and to evaluate the therapeutic effect of treating comorbidities and avoiding certain antiretroviral drugs.
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PMID:Hepatic steatosis and HIV infection. 1598 31

Cardiac contractility in cirrhosis is normal at baseline but hyporesponsive to stimuli, a phenomenon known as 'cirrhotic cardiomyopathy'. The pathogenesis remains unclear. Endocannabinoids are vasoactive, but have not previously been examined in the cirrhotic heart. We therefore aimed to systematically clarify a possible role of endocannabinoids in the pathogenesis of cirrhotic cardiomyopathy. Cirrhosis was induced in Sprague-Dawley rats by bile duct ligation; controls underwent a sham operation. At 4 weeks after operation, isolated left ventricular papillary muscle contractility was studied. Dose-response curve for a beta-adrenergic agonist isoproterenol was constructed in the presence and absence of a CB-1 antagonist AM251 (1 microM). Cirrhotic muscles had a blunted response to isoproterenol, which was completely restored by AM251. Dose-response curves to anandamide, and CB-1 and CB-2 protein and mRNA expression in Western blot and reverse transcriptase-polymerase chain reaction experiments were not significantly different between cirrhotic and sham muscles. Force-frequency relationship studies were performed in cirrhotic and normal muscles. At higher frequencies, anandamide reuptake blockers (VDM11 and AM404) significantly enhanced muscle relaxation in cirrhotic muscles, but not in controls. This effect was completely blocked by AM251 and pertussis toxin, whereas tetrodotoxin partially reversed it. Taken together, these results indicate a pathogenic role for increased local (neuronal) production of endocannabinoids, mediated by a G(i)-protein-dependent CB-1-responsive pathway in cirrhotic cardiomyopathy. The increased tachycardia-stress-induced release of endocannabinoids may help explain why contractility is normal at baseline but attenuated with stress.
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PMID:Role of endocannabinoids in the pathogenesis of cirrhotic cardiomyopathy in bile duct-ligated rats. 1602 38

Since highly active antiretroviral therapies became available, the future of HIV-infected patients has been transformed. However, 20 to 25% of HIV patients are co-infected with hepatitis B or C viruses, and the course of these diseases has worsened, since these patients have an enhanced sensitivity to the hepatic toxicity of antiretrovirals. The relation between high antiretroviral concentrations and toxicity has been clearly demonstrated with certain protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTI) that have a predominantly hepatic metabolism (CYP4503A4). The nucleoside reverse transcriptase inhibitors (NRTI) are not predominantly metabolized by the liver, but may nevertheless be toxic for the liver through mitochondrial involvement. The hepatic toxicity observed in a patient treated with early or delayed antiretrovirals may be due to a cytolytic, cholestatic or mixed, direct or indirect, mechanism. Before initiating antiretroviral treatments, hepatic fibrosis must be explored (punch biopsy, biological fibrosis test, and Child-Pugh's score). It is recommended that the most hepatotoxic drugs be avoided, notably didanosine, didanosine+stavudine, nevirapine, and full-dose ritonavir. Although it is possible to initiate an antiretroviral at the standard dose in patients with cirrhosis (the therapeutic margin with antiretrovirals is wide), early assays are essential, particularly with PI and NNRTI, to adjust the dose and avoid adverse events. In any event rigorous monitoring is a must.
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PMID:[Antiretroviral agents in HIV-infected patients with cirrhosis]. 1602 67

In the Asia Pacific region Human Immunodeficiency virus (HIV) is often acquired in individuals already infected with hepatitis B virus (HBV). The immune suppression caused by HIV infection reduces cellular immune response against HBV and liver inflammation may improve, but the risk of developing cirrhosis is not. HBV infection does not affect the progression of HIV disease. Anti-retroviral agents may be directly hepatotoxic and cause ALT elevations in patients with chronic hepatitis. Highly active anti-retroviral therapy (HAART) improves immunity and as cytotoxic lymphocyte responses improve, hepatitis flares can occur, usually r within 3 months of initiation of HAART. These hepatitis flares may be followed by normalization of ALT and clearance of HBVDNA. If lamivudine is included in the HAART regime, hepatitis flares may not occur till late and these late flares signal the development of lamivudine resistant HBV strains (90% of HBV/HIV co-infection). Treatment options for chronic HBV infection include interferon (IFN), and nucleoside analogues. Lamivudine, adefovir dipivoxil, tenofovir disoproxil fumarate (DF) are nucleoside analogues with activity against both HBVDNA polymerase and HIV reverse transcriptase. The latter two compounds have added activity against lamivudine resistant HBVDNA. Lamivudine should be avoided in the initial treatment of both hepatitis B as well as HIV because of the high incidence of resistance. Interferon should be considered first for treatment of HBV in HIV co-infected individuals and is usually unsuccessful in the later stages of HIV infection when immune suppression is extreme. As new and improved agents in HAART continue to prolong survival, the use of liver transplantation for cirrhotic patients co-infected with HIV and HBV may increase.
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PMID:Treatment of chronic hepatitis B in HIV co-infected patients. 1610 74

Adefovir dipivoxil is an up-to-date drug for the treatment of chronic hepatitis B. Adefovir dipivoxil is a lipophilic prodrug of adefovir, an analogue of adenosine monophosphate (AMP). It suppresses efficaciously the replication of the hepatitis B virus and of other viruses. After conversion to its active metabolite, it can inhibit both DNA polymerase and reverse transcriptase. It is well absorbed by the intestinal mucosa, its bio-availability is approx. 59%, it is distributed to most tissues and eliminated by the kidneys. There are no known clinically significant drug interactions. The recommended dose is 10 mg/day; in patients with renal impairment the dose must be adjusted. Treatment has to continue for at least one year. Compared with lamivudine, adefovir resistance develops more slowly. Virus resistant to lamivudine is sensitive to adefovir and vice versa. The efficacy and safety of this treatment have been verified in four published clinical trials with more than one thousand patients, including patients with decompensated cirrhosis prior to and after liver transplantation. In these patients there was an improvement of several virological, biochemical and clinical markers. The drug is well tolerated. Seen adverse side-effects were gastrointestinal disorders, headache and a mild to moderate increase in serum creatinine. There are no specific contraindications to the therapy, with the exception of hypersensitivity. However, there are only insufficient data on the administration of the drug to pregnant women and to children. Adefovir dipivoxil offers a new treatment possibility for patients presenting a chronic infection with the hepatitis B virus, especially those infected with a lamivudine-resistant virus. Key words: adefovir dipivoxil-chronic hepatitis B-hepatitis B virus-lamivudine.
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PMID:[Adefovir dipivoxil-a new effective treatment for chronic infection with hepatitits B virus.]. 1613 74

Growth arrest and DNA damage 45-alpha (GADD45-alpha) is a nuclear protein involved in maintenance of genomic stability, DNA repair, and suppression of cell growth through interaction with nuclear elements, including cyclin-dependent kinase inhibitor 1A (CDKN1A) and PCNA. In this study, GADD45-alpha expression was assessed in 28 cases of hepatocellular carcinoma (HCC) and matched cirrhosis tissues, and correlated with the presence of DNA-bound PCNA and CDKN1A as markers of DNA repair, as well as with clinicopathologic variables including histopathologic grade, tumor size, nodularity, viral status, alpha-fetoprotein serum levels, and p53 and Ki67 immunostaining. GADD45-alpha and CDKN1A messenger RNA (mRNA) were analyzed by reverse transcriptase-polymerase chain reaction. GADD45-alpha protein expression was evaluated by Western blot (WB) and enzyme-linked immunosorbent assays (ELISAs). PCNA and CDKN1A DNA-bound fractions were determined by WB. GADD45-alpha mRNA was down-regulated in 20 of 26 HCCs with respect to matched cirrhosis, but no correlation was found with the corresponding protein levels assessed by both WB and ELISA. GADD45-alpha and CDKN1A protein levels were related to each other both in cirrhotic and in neoplastic tissues, and a concordant up- or down-regulation was observed in HCCs with respect to cirrhosis. DNA-bound PCNA and CDKN1A were present in 5 HCCs and were associated with higher GADD45-alpha protein levels assessed by ELISA. No significant association was found in HCCs between GADD45-alpha protein expression and histopathologic grading, nodule size, focality, and proliferation, whereas a positive correlation was found with alpha-fetoprotein serum levels. In conclusion, GADD45-alpha mRNA was down-regulated with respect to matched cirrhosis in most HCCs; however, no correlation was found between mRNA and protein levels. GADD45-alpha protein levels were higher in HCCs with DNA-bound CDKN1A and PCNA, suggesting a possible role in DNA repair.
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PMID:GADD45-alpha expression in cirrhosis and hepatocellular carcinoma: relationship with DNA repair and proliferation. 1626 Feb 67


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