Gene/Protein Disease Symptom Drug Enzyme Compound
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All classes of antiretroviral (ARV) therapy have been associated with asymptomatic elevations of alanine aminotransferase/aspartate aminotransferase (ALT/AST) levels, and much less frequently with serious, and at times life threatening, clinical liver hepatotoxicity. The relationship between the risk of developing serious clinical liver injury and the rate and severity of elevated asymptomatic ALT/AST levels is poorly understood. Boehringer Ingelheim has recently completed the Viramune Hepatic Safety Project; its primary objective was to identify risk factors for antiretroviral-associated hepatotoxicity. Data from 1731 nevirapine-treated patients and 1912 control patients who took part in Boehringer Ingelheim-controlled clinical trials as well as 814 nevirapine-treated patients in uncontrolled trials were analyzed. Risk factors for asymptomatic ALT/AST elevations during nevirapine therapy included baseline elevations of ALT/AST levels > 2.5x upper limit of normal (RR = 4.3, p < .01) and co-infection with hepatitis B (RR = 2.3, p < .01) or hepatitis C (RR = 5.2, p < .01). An analysis of ALT/AST elevations > 5x ULN for patients stratified by baseline CD4 cell count demonstrated that men with > or = 400 CD4 cells/mm3 were at increased risk of asymptomatic transaminase elevations while taking nevirapine (RR = 1.6, p < .01). No consistent CD4 cell count cutoff could be identified in women that was associated with an increased risk of ALT/AST elevations. Analyses from five large observational cohorts (N = 8711) demonstrated no significant differences in the rate of serious hepatic events among antiretroviral regimens, including between the non-nucleoside reverse transcriptase inhibitors nevirapine and efavirenz. Use of nevirapine was not associated with a significantly increased risk of clinical hepatotoxic events, including liver failure or liver related death, compared to therapy with other antiretroviral drugs.
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PMID:A comprehensive hepatic safety analysis of nevirapine in different populations of HIV infected patients. 1502 21

The use of all potent drugs is associated with toxicities and antiretroviral (ARV) drugs are no exception. Antiretroviral therapy-associated hepatic toxicity is of increasing concern in the management of patients with HIV/AIDS. Liver toxicity has been reported in some HIV-infected patients being treated with drugs from all of these classes of ARV drugs: protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Although the majority of cases involve asymptomatic elevations of liver enzymes (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]), severe, and, in a minority of cases, life threatening, liver disease has been reported in patients treated with ARV drugs. The exact causes of elevated plasma levels of AST and ALT are complex and, in many cases, obscure. The combination of viral hepatic disease, drugs that act adversely directly on the liver and drugs that act on other systems of the body which in turn, adversely affect the liver, can result in hepatic toxicity. Such toxicity may be inappropriately attributed solely to the direct effect of a drug. Knowledge of the possible causes of liver toxicity, and ways to avoid it, should reduce the risk of developing hepatotoxicity. The physician's task is to prevent the development of liver toxicity, e.g., by choosing appropriate therapeutic regimens and by careful management of the patient. This involves frequent monitoring of the patient, both clinically and by utilizing liver function tests on a regular basis. If signs and symptoms of liver disease do develop, prompt and expert management is essential. This review discusses the influence of a number of factors on hepatic toxicity including viral hepatitis, insulin resistance and the specific ARV drugs used in the treatment of patients with HIV/AIDS.
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PMID:Managing antiretroviral-associated liver disease. 1456 56

Lamivudine is a nucleoside analogue with potent inhibitory effects on hepatitis B virus (HBV) polymerase/reverse transcriptase activity. The rate of hepatitis B e antigen (HBeAg) seroconversion in a large series of Asian patients treated with lamivudine 100 mg daily for 1 year was only 16% and the incidence of YMDD mutants was 14%. Further analysis of this Asian trial has shown that patients with a pretreatment alanine aminotransferase (ALT) level higher than 5-fold the upper limit of normal (ULN) have a much higher HBeAg seroconversion rate as compared with patients with a pretreatment ALT level <2 x upper limit of normal (64 vs. 5%; p < 0.001). In order to avoid the development of YMDD mutants, we selected 186 patients with acute exacerbation for treatment with lamivudine during 9 months, if possible, and not more than 15 months. They were all seropositive for both hepatitis B surface antigen and HBeAg for more than 6 months and also had serum HBV DNA; 138 (74%) of them were male. HBV genotypes were A in 2 (1%), B in 115 (62%), C in 65 (35%), D in 2 (1%) and F in the remaining 2 (1%). Four patients (2%) had liver cirrhosis. They had mean pretreatment levels of ALT at 608 IU/l (range: 184-2,400 IU/l), total bilirubin at 1.5 mg/dl (0.3-14.8 mg/dl), and HBV DNA at 2,246 pg/ml (0.5-25,903 pg/ml). After a median of 8.2 months (3-15 months) on lamivudine, 96 patients (51%) achieved HBeAg seroconversion, while the other 90 (48%) patients did not. Genotype B was detected comparably frequently in seroconverters and nonconverters (63 vs. 61%). During 1-year follow-up after withdrawal of lamivudine, 56 (58%) of the 96 seroconverters experienced flare-ups with ALT levels elevated higher than 5 x ULN in 50 (89%). Of 90 patients who remained HBeAg-positive, in contrast, 80 (86%) experienced ALT flares (with ALT >5 x ULN in 84%) within 1 year. YMDD mutants did not develop in any of these 186 patients during the course of lamivudine therapy. In conclusion, short-term lamivudine therapy in patients with chronic active hepatitis B can reduce the incidence of YMDD mutants and achieve an acceptable HBeAg seroconversion rate. However, the relapse rate was high (60% during 1-year follow-up). Further study is needed to establish how to improve a sustained HBeAg response.
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PMID:Short-term lamivudine therapy in patients with chronic hepatitis B. 1468 53

Our previous study demonstrated that polycationic liposomes are highly stable in the bloodstream and represent an effective agent for liver gene delivery. We report here that liposome-mediated extracellular superoxide dismutase (EC-SOD) gene delivery successfully prevented acute liver injury in mice. The therapeutic efficacy of EC-SOD gene delivery by polycationic liposomes was determined against the toxicity of superoxide anions and hydroxyethyl radicals in HepG2 cells and in a mouse model of acute liver injury caused by D-galactosamine and lipopolysaccharide intoxication. Transfection of HepG2 cells with an EC-SOD plasmid led to a striking increase in superoxide dismutase activity in the medium. The transfected cells had much less cell death after reactive oxygen species exposure compared with untransfected or control plasmid-transfected cells. In a model of acute liver injury, serum alanine aminotransferase levels in mice receiving portal vein injections of EC-SOD lipoplexes were much lower than in those receiving normal saline, liposomes alone, or control lipoplexes. Liver histology confirmed that there was less cell death in the EC-SOD lipoplex-treated group. Quantitative reverse transcriptase polymerase chain reaction showed a 55-fold increase in human EC-SOD gene expression in the liver of mice injected with EC-SOD lipoplexes. Serum superoxide dismutase activity in EC-SOD lipoplex-treated mice was higher than in the control groups; this was associated with higher liver glutathione levels and reduced lipid peroxidation. In conclusion, polycationic liposome-mediated EC-SOD gene delivery protects against reactive oxygen species toxicity in vitro and against lipopolysaccharide-induced acute liver injury in D-galactosamine-sensitized mice.
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PMID:Liposome-mediated extracellular superoxide dismutase gene delivery protects against acute liver injury in mice. 1523 3

Abnormal liver function tests are frequently observed in HIV-infected individuals receiving nevirapine (NVP). Here we investigate the relationship between total and unbound plasma concentrations of NVP and the liver enzymes alanine aminotransferase (ALT) and gamma-glutamyl transferase (gammaGT). HIV-infected individuals [n = 85, 22 female, 34 hepatitis C or B virus (HCV or HBV(+))] receiving NVP (200 mg bd; median duration 66 weeks, range 3-189) and two nucleoside reverse transcriptase inhibitors (NRTIs) were enrolled into this study. Blood samples were taken at C(trough) (12 hr postdose) for measurement of NVP and liver function tests (ALT and gammaGT). Plasma protein bound and unbound drug was separated using ultrafiltration and NVP concentrations quantified using HPLC-MS/MS. A linear relationship was observed between total and unbound NVP C(trough) (r(2) = 0.77, p < 0.0001). Patients with elevated ALT (>37 IU/liter; n = 31) had higher NVP unbound C(trough) than those with ALT within the normal range (median 2268 vs. 1694 ng/ml, p = 0.04) but there was no difference in total C(trough). Logistic regression revealed no association between higher NVP C(trough) and ALT elevations. Significantly higher NVP total and unbound C(trough) were observed in patients with increased gammaGT (>40 IU/liter; n = 63; total 6747 vs. 4530 ng/ml, p = 0.001; unbound 2113 vs. 1557 ng/ml, p = 0.03). Significantly higher unbound NVP C(trough) was observed in HCV/HBV(+) (median 2275 vs. 1726 ng/ml, p = 0.02) and on bivariate analysis, higher NVP C(trough) was associated with HCV/HBV coinfection (chi(2) = 4.228; p = 0.04). Overall we found no strong association between NVP concentrations and hepatotoxicity. Although in this study NVP was well tolerated in HCV/HBV coinfected patients, higher plasma concentrations were observed.
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PMID:The relationship between nevirapine plasma concentrations and abnormal liver function tests. 1530 17

In the present study, we investigated the protective effect of Lycium chinense Miller (Solanaceae) fruit (LFE) against CCl(4)-induced hepatotoxicity and the mechanism underlying these protective effects in rats. The pretreatment of LFE has shown to possess a significant protective effect by lowering the serum aspartate and alanine aminotransferase (AST and ALT) and alkaline phosphatase (ALP). This hepatoprotective action was confirmed by histological observation. In addition, pretreatment of LFE prevented the elevation of hepatic malondialdehyde (MDA) formation and the depletion of reduced glutathione (GSH) content and catalase activity in the liver of CCl(4)-injected rats. The LFE also displayed hydroxide radical scavenging activity in a dose-dependent manner (IC(50) = 83.6 microg/ml), as assayed by electron spin resonance (ESR) spin-trapping technique. The expression level of cytochrome P450 2E1 (CYP2E1) mRNA and protein, as measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis, was significantly decreased in the liver of LFE-pretreated rats when compared with that in the liver of control group. Based on these results, it was suggested that the hepatoprotective effects of the LFE might be related to antioxidative activity and expressional regulation of CYP2E1.
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PMID:Protective effect of Lycium chinense fruit on carbon tetrachloride-induced hepatotoxicity. 1561 74

The objective of this study was to find predictive factors of lopinavir/ritonavir (LPV/r) discontinuation for drug-related toxicities in highly pre-treated human immunodeficiency virus (HIV)-infected subjects. The study was an observational study of HIV patients starting LPV/r with HIV RNA > 3log10 copies/mL and a follow-up > or = 6 months. Parameters studied were HIV RNA, CD4+ cell counts, metabolic parameters and drug-related adverse events. Acquired immune deficiency syndrome (AIDS) events and deaths were recorded. The Kaplan-Meier (KM) model was used to estimate time-dependent probability, and the multivariable Cox model to identify predictors of LPV/r discontinuation for adverse events. The study evaluated 416 HIV-infected patients. Seventy-seven patients (18.5%) discontinued LPV/r for toxicities. Adverse events leading to LPV/r discontinuation were gastrointestinal symptoms in 40 cases, hyperlipidaemia in 27 and increase of aspartate aminotransferase (AST)/alanine aminotransferase (ALT) in 10 patients. Nineteen patients (4.6%) developed an AIDS event during observation and 15 (3.6%) died. The KM probability of LPV/r discontinuation for toxicities was 5.3% (range 3.1-7.5%) at month 12 and 15.7% (range 12.1-19.3%) at month 24. Subjects with hepatitis C virus (HCV)-HIV co-infection (odds ratio (OR) 7.40; 95% confidence interval (CI) 3.73-14.66 versus HCV-negative; P = 0.001) and receiving LPV/r plus nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitor (PI)/non-nucleoside reverse transcriptase inhibitor (NNRTI) (OR 1.74; 95% CI 1.04-2.91 versus LPV/r plus only NRTIs; P = 0.04) showed a higher risk of LPV/r discontinuation by a Cox analysis, whereas non-intravenous drug abusers (IVDUs) (OR 0.40; 95% CI 0.24-0.67 versus IVDUs; P = 0.001) had a lower risk. The rate of discontinuation for toxicity decreased by 17% for each additional month of LPV/r exposure (OR 0.83; 95% CI 0.80-0.86 for each additional month; P < 0.001). LPV/r was substantially well tolerated. Diarrhoea was the most frequent adverse event leading to discontinuation. HCV-HIV co-infected patients and patients with a short exposure to LPV/r have a higher risk of discontinuing LPV/r and should be strictly monitored.
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PMID:Predictive factors of lopinavir/ritonavir discontinuation for drug-related toxicity: results from a cohort of 416 multi-experienced HIV-infected individuals. 1587 62

In vivo studies have shown that chronic alcohol consumption sensitizes the liver to endotoxemic shock, leading to liver microcirculation disruption. In the present study, we investigated the molecular mechanisms involved, focusing on endothelial nitric oxide synthase (eNOS) activity and regulation, which represents one of the major vasodilatory pathways. Male Sprague-Dawley rats were fed an alcohol liquid diet or a control isocaloric diet for 5 weeks. Priming effects of ethanol were studied in a model with or without a 24-h LPS treatment (1 mg/kg body weight). At the end of the diet, liver tissue was harvested for western blot, reverse transcriptase-PCR, histological analysis, and immunostaining and blood for serum alanine aminotransferase analysis. Chronic ethanol and LPS alone induced a mild hepatitis and infiltration, respectively. Combined, LPS and chronic ethanol feeding showed a synergistic effect on the liver, leading to extensive steatohepatitis with extensive focal necrosis associated with significantly higher levels of serum ALT. Chronic ethanol and LPS significantly inhibited eNOS activity, but exerted their effects through different mechanisms. Caveolin-1, an eNOS inhibitory protein, was upregulated after LPS and chronic alcohol consumption. Additionally, chronic alcohol consumption down-regulated endothelin B receptor, eNOS protein levels, and eNOS phosphorylation. In conclusion, chronic ethanol consumption and LPS share a similar pathophysiology and both lead to the impairment of eNOS activity, but through distinct molecular mechanisms. The presence of focal necrosis in a mild stress model could provide a good animal study to investigate the advanced stages of alcoholic liver diseases.
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PMID:Chronic ethanol sensitizes the liver to endotoxin via effects on endothelial nitric oxide synthase regulation. 1624 31

Lamivudine and adefovir have potent inhibitory effects on hepatitis B virus (HBV) replication. Although short-term therapy is feasible in a selected subgroup of patients, prolonged therapy is required for sustained suppression in the majority of patients. However, HBV species with mutations in the tyrosine-methionine-aspartate-aspartate (YMDD) locus of the HBV RNA-dependent DNA polymerase (rtM204 I/V) conferring resistance to lamivudine may emerge after 9-10 months therapy. The incidence increases with duration of therapy up to 70% after 5 years lamivudine therapy. Serum alanine aminotransferase (ALT) elevation and HBV DNA rebound ( I log) occur in >90% of the patients with rtM204 I/V during continued lamivudine therapy. Marked flare of serum ALT may occur, sometimes severe, and may be complicated with decompensation or even fatality. The initial clinical and histologic improvement may also reverse after emergence of rtM204 IN Studies do suggest that stopping seems better than continuing lamivudine therapy. Limited data show that interferon therapy seems ineffective. Add-on adefovir therapy is effective in suppressing rtM204 I/V in both compensated and decompensated patients. Switching to adefovir monotherapy is effective and safe even in cirrhotic patients with decompensation. The overall incidence of adefovirresistant rtN236T and A181V is low, being 0 after one year and 5.9% after 3 years' therapy. The impact of adefovir resistance is less clear but is responsive to lamivudine therapy. In conclusion, monitoring of viral breakthrough to start effective intervention is mandatory during direct antiviral therapy.
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PMID:The current management of HBV drug resistance. 1646 Dec 16

Chronic hepatitis B is a common disease and approximately 20% of infected patients with compensated cirrhosis will decompensate over 5 years. If untreated, the survival of decompensated cirrhosis is poor (15% at 5 years). The extent of hepatitis B virus (HBV) replication, as assessed by serum HBV-DNA level, is a strong predictor of the risk of disease progression and hepatocellular carcinoma. This provides a rationale for antiviral therapy to arrest progression of liver disease. Lamivudine is a pyrimidine analogue that inhibits HBV-DNA reverse transcriptase. It decreases HBV replication, normalises alanine aminotransferase levels and reduces hepatic inflammation and fibrosis in patients with chronic hepatitis B. This article will focus on the use of lamivudine in patients with HBV-cirrhosis. In patients with compensated HBV-cirrhosis, a randomised, placebo-controlled trial has shown that lamivudine significantly reduced the rate of disease progression and hepatocellular carcinoma development over a 3-year period. In patients with decompensated cirrhosis, treatment with lamivudine can produce spectacular improvements of liver function, but the improvement is slow and a clinical benefit is usually not observed until after at least 3-6 months of treatment. A major drawback of lamivudine treatment is the development of resistance, observed in 15-20% of patients after 1 year and up to 70% after 5 years of continued treatment. Thus, patients with HBV-cirrhosis treated with lamivudine should have regular monitoring of serum HBV-DNA levels and prompt institution of additional antiviral therapy if viral breakthrough is observed. Adefovir, tenofovir and entecavir have demonstrated efficacy in patients with lamivudine resistance. In patients with decompensated cirrhosis, in whom the development of resistance can be fatal, combination therapy (such as lamivudine plus adefovir) may prove more effective than monotherapy and this issue needs further study.
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PMID:Lamivudine treatment in patients with chronic hepatitis B and cirrhosis. 1692 9


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