Risk factors for hepatotoxicity in HIV-1-infected patients receiving ritonavir and saquinavir with or without stavudine. Prometheus Study Group

PXR-mediated idiosyncratic drug-induced liver injury: mechanistic insights and targeting approaches

INTRODUCTION

The human liver is the center for drug metabolism and detoxification and is, therefore, constantly exposed to toxic chemicals. The loss of liver function as a result of this exposure is referred to as drug-induced liver injury (DILI). The pregnane X receptor (PXR) is the primary regulator of the hepatic drug-clearance system, which plays a critical role in mediating idiosyncratic DILI.

AREAS COVERED

This review is focused on common mechanisms of PXR-mediated DILI and on in vitro and in vivo models developed to predict and assess DILI. It also provides an update on the development of PXR antagonists that may manage PXR-mediated DILI.

EXPERT OPINION

DILI can be caused by many factors, and PXR is clearly linked to DILI. Although emerging data illustrate how PXR mediates DILI and how PXR activity can be modulated, many questions concerning the development of effective PXR modulators remain. Future research should be focused on determining the mechanisms regulating PXR functions in different cellular contexts.

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism.

Liver Toxicity of Current Antiretroviral Regimens in HIV-Infected Patients with Chronic Viral Hepatitis in a Real-Life Setting: The HEPAVIR SEG-HEP Cohort

OBJECTIVE

To assess the current frequency of ART-associated grade 3-4 transaminase elevations (TE) and grade 4 total bilirubin elevations (TBE) in HIV-infected patients with chronic hepatitis B and/or C, who start a new regimen of ART.

PATIENTS AND METHODS

A total of 192 pre-treated or treatment-naive HIV infected patients with HBV and/or HCV-coinfection who started ART in eight Southern Spanish centers from July/2011-December/2013, were followed for 12 months in this prospective study.

RESULTS

Forty-one (21.4%) subjects had been naïve to ART, median (IQR) follow-up was 11.6 (5.6-12.9) months. The most frequently initiated NRTI were tenofovir/emtricitabine [49 patients (25.5%)]. Eighty-nine (46.4%) patients started a ritonavir-boosted protease inhibitor and 77 (40.1%) individuals a NNRTI. Raltegravir and maraviroc were initiated in 24 (12.5%) and 9 (4.7%) individuals. Ten [5.21%; 95% confidence interval (CI): 2.53%-9.37%] patients presented grade 3 TE, while 8 (4.17%; 95%CI: 1.82%-8.04%) subjects showed grade 4 TBE. No episodes of grade 4 TE or ART discontinuation due to hepatotoxic events were observed. The use of ritonavir-boosted atazanavir was the only independent predictor for grade 4 TBE [adjusted odds ratio: 7.327 (95%CI: 1.417-37.89); p = 0.018] in an analysis adjusted for age, sex and baseline HIV-RNA levels, while no factor could be independently associated with grade 3-4 TE.

CONCLUSIONS

Currently, the frequency of severe ART-associated TE and TBE under real-life conditions in patients with chronic viral hepatitis is similar to what has been reported previously. However, episodes of grade 4 TE are less frequent and severe TE appears to be of lesser concern.

Hepatotoxicity and associated risk factors in HIV-infected patients receiving antiretroviral therapy at Felege Hiwot Referral Hospital, Bahirdar, Ethiopia

Background

In Human Immunodeficiency Virus (HIV) infected patients on antiretroviral treatment (ART), hepatotoxicity is life threatening. Its outcome may lead to liver failure and death. This study was conducted to determine the rate and determinants of elevated alanine amino transferase (ALT) (referred as >40IU/L for both males and females).

Methods

A cross sectional study was conducted on HIV infected individuals who are on ART and suspected of drug resistance at Felege Hiwot Referral Hospital, Bahir Dar from July to December 2012. Venous bloods were collected from each patient and processed parallely to determine ALT, number of HIV RNAs, CD4 and CD8 T cells count, anti hepatitis C virus (HCV) and hepatitis B surface antigen.

Results

Out of 269 HIV infected patients receiving ART, 32% were confirmed of grades 1–4 levels of elevated ALT. The rate of severe hepatotoxicity (grade 3 and 4) was 1.84%. Patients with increased CD8 T cell counts (P=0.011; AOR=1.82; CI: 1.12 –2.54), alcohol over use (P=0.014; AOR = 1.23; CI: 1.36–3.29) and detectable HIV-1 RNA copies (P=0.015; AOR=2.07; CI: 1.15–3.74) independently predicts the elevation of ALT.

Conclusions

In HIV infected patients on ART, extreme elevations of ALT were infrequent but minor elevations were common so that patient-linked variables such as use of alcohol intake must be taken in to account for better clinical management of ART patients. The role of active HCV co-infection on the treatment outcome of ART should be further studied.

Modelling Hepatotoxicity of Antiretroviral Therapy in the Liver during HIV Monoinfection

Liver related complications are currently the leading cause of morbidity and mortality among human immunodeficiency virus (HIV) infected individuals. In HIV monoinfected individuals on therapy, liver injury has been associated with the use of antiretroviral agents as most of them exhibit some degree of toxicity. In this study we proposed a mathematical model with the aim of investigating hepatotoxicity of combinational therapy of antiretroviral drugs. Therapy efficacy and toxicity were incorporated in the model as dose-response functions. With the parameter values used in the study, protease inhibitors-based regimens were found to be more toxic than nonnucleoside reverse transcriptase inhibitors-based regimens. In both regimens, the combination of stavudine and zidovudine was the most toxic baseline nucleoside reverse transcriptase inhibitors followed by didanosine with stavudine. However, the least toxic combinations were zidovudine and lamivudine followed by didanosine and lamivudine. The study proposed that, under the same second line regimens, the most toxic first line combination gives the highest viral load and vice versa.

Long-term responses to first-line antiretroviral therapy in HIV and hepatitis B co-infection in Ghana

OBJECTIVES

To observe the long term response to first-line antiretroviral therapy (ART) in HIV and hepatitis B virus (HBV) co-infected patients in Ghana and explore predictors of poor clinical outcomes.

METHODS

Retrospective cohort study of hepatitis B surface antigen (HBsAg) positive and negative patients receiving predominantly NNRTI-based ART with lamivudine plus either zidovudine or stavudine for up to seven years. Cox proportional hazards and Kaplan Meier survival analyses compared clinical outcomes and identified baseline characteristics predictive of poor outcomes. A mixed effects model compared changes in CD4 counts.

RESULTS

A total of 299 HBsAg-positive and 1869 HBsAg-negative patients started ART between 2004 and 2008. Over a median 35 months of follow-up, HBsAg-positive patients were more likely to die or default care than HBsAg-negative patients, aHR 1.36 (95% CI, 1.03-1.80). HBsAg-positive patients were also more likely to develop Grade 3/4 hepatotoxicity than HBsAg-negative patients, HR 1.99 (1.16-3.40) on survival analysis. There was no significant difference in CD4 responses between HBsAg-positive and HBsAg-negative patients.

CONCLUSIONS

HBsAg-positive patients are at significantly increased risk of adverse clinical outcomes after starting ART. Further studies are warranted to evaluate whether these risks remain now that tenofovir is becoming routinely available in Ghana.

Safety of protease inhibitors in HIV-infected pregnant women

The dire conditions of the human immunodeficiency virus/acquired immune deficiency syndrome epidemic and the immense benefits of antiretroviral prophylaxis in prevention of mother-to-child transmission far outweigh the potential for adverse effects and undeniably justify the rapid and widespread use of this therapy, despite incomplete safety data. Highly active antiretroviral therapy has now become standard care, and more than half the validated regimens include protease inhibitors. This paper reviews current knowledge of the safety of these drugs during pregnancy, in terms of maternal and fetal outcomes. Transfer of protease inhibitors across the placenta is known to be minimal, and current data about birth defects and fetal malignancies are reassuring. Maternal liver function and glucose metabolism should be monitored in women treated with protease inhibitor-based regimens, but concerns about the development of maternal resistance, should treatment be discontinued, have been shown to be groundless. Neonates should be screened for hematologic abnormalities, although these are rarely severe or permanent and are not usually related to the protease inhibitor component of the antiretroviral combination. Current findings concerning pre-eclampsia and growth restriction are discordant, and further research is needed to address the question of placental vascular complications. The increased risk of preterm birth attributed to protease inhibitors should be interpreted with caution considering the discrepant results and the multitude of confounding factors often overlooked. Although data are thus far reassuring, further research is needed to shed light on unresolved controversies about the safety of protease inhibitors during pregnancy.

Mathematical modeling of liver enzyme elevation in HIV mono-infection

HIV-infected individuals are increasingly becoming susceptible to liver disease and, hence, liver-related mortality is on a rise. The presence of CD4+ in the liver and the presence of C-X-C chemokine receptor type 4 (CXCR4) on human hepatocytes provide a conducive environment for HIV invasion. In this study, a mathematical model is used to analyse the dynamics of HIV in the liver with the aim of investigating the existence of liver enzyme elevation in HIV mono-infected individuals. In the presence of HIV-specific cytotoxic T-lymphocytes, the model depicts a unique endemic equilibrium with a transcritical bifurcation when the basic reproductive number is unity. Results of the study show that the level of liver enzyme alanine aminotransferase (ALT) increases with increase in the rate of hepatocytes production. Numerical simulations reveal significant elevation of alanine aminotransferase with increase in viral load. The findings presuppose that while liver damage in HIV infection has mostly been associated with HIV/HBV coinfection and use of antiretroviral therapy (ART), it is possible to have liver damage solely with HIV infection.

HIV antiretroviral medications and hepatotoxicity

PURPOSE OF REVIEW

This review considers the differential diagnosis, pathophysiology and risk of hepatotoxicity of specific antiretroviral medications.

RECENT FINDINGS

Currently prescribed antiretroviral medications are associated with an incidence of grade 3/4 liver enzyme elevation of less than 5%. Clinically apparent hepatotoxicity rates are much lower. The risk of adverse events with combination HIV and hepatitis C virus treatments is low, assuming that several nucleosides including didanosine and stavudine are avoided.

SUMMARY

Irrespective of the HIV antiretroviral regimen prescribed, careful observation of liver function and enzymes is advised, especially in those with comorbid liver disease. The majority of patients do not experience treatment-limiting liver toxicities, achieve virological suppression, and realize immunological restoration.

Effectiveness of protease inhibitor monotherapy versus combination antiretroviral maintenance therapy: a meta-analysis

BACKGROUND

The unparalleled success of combination antiretroviral therapy (cART) is based on the combination of three drugs from two classes. There is insufficient evidence whether simplification to ritonavir boosted protease inhibitor (PI/r) monotherapy in virologically suppressed HIV-infected patients is effective and safe to reduce cART side effects and costs.

METHODS

We systematically searched Medline, Embase, the Cochrane Library, conference proceedings and trial registries to identify all randomised controlled trials comparing PI/r monotherapy to cART in suppressed patients. We calculated in an intention to treat (loss-of follow-up, discontinuation of assigned drugs equals failure) and per-protocol analysis (exclusion of protocol violators following randomisation) and based on three different definitions for virological failure pooled risk ratios for remaining virologically suppressed.

FINDINGS

We identified 10 trials comparing 3 different PIs with cART based on a PI/r plus 2 reverse transcriptase inhibitors in 1189 patients. With the most conservative approach (viral load <50 copies/ml on two consecutive measurements), the risk ratios for viral suppression at 48 weeks of PI/r monotherapy compared to cART were in the ITT analysis 0.94 8 (95% CI 0.89 to 1.00) p = 0.06; risk difference -0.06 (95%CI -0.11 to 0) p = 0.05, p for heterogeneity  = 0.08, I(2) = 43.1%) and in the PP analysis 0.93 ((95%CI 0.90 to 0.97) p<0.001; risk difference -0.07 (95%CI -0.10 to -0.03) p<0.001, p for heterogeneity  = 0.44, I(2) = 0%). Reintroduction of cART in 44 patients with virological failure led in 93% to de-novo viral suppression.

INTERPRETATION

Virologically well suppressed HIV-infected patients have a lower chance to maintain viral suppression when switching from cART to PI/r monotherapy. Failing patients achieve high rates of de-novo viral suppression following reintroduction of reverse transcriptase inhibitors.

Hepatic profile analyses of tipranavir in Phase II and III clinical trials

Background

The risk and course of serum transaminase elevations (TEs) and clinical hepatic serious adverse event (SAE) development in ritonavir-boosted tipranavir (TPV/r) 500/200 mg BID recipients, who also received additional combination antiretroviral treatment agents in clinical trials (TPV/r-based cART), was determined.

Methods

Aggregated transaminase and hepatic SAE data through 96 weeks of TPV/r-based cART from five Phase IIb/III trials were analyzed. Patients were categorized by the presence or absence of underlying liver disease (+LD or -LD). Kaplan-Meier (K-M) probability estimates for time-to-first US National Institutes of Health, Division of AIDS (DAIDS) Grade 3/4 TE and clinical hepatic SAE were determined and clinical actions/outcomes evaluated. Risk factors for DAIDS Grade 3/4 TE were identified through multivariate Cox regression statistical modeling.

Results

Grade 3/4 TEs occurred in 144/1299 (11.1%) patients; 123/144 (85%) of these were asymptomatic; 84% of these patients only temporarily interrupted treatment or continued, with transaminase levels returning to Grade ≤ 2. At 96 weeks of study treatment, the incidence of Grade 3/4 TEs was higher among the +LD (16.8%) than among the -LD (10.1%) patients. K-M analysis revealed an incremental risk for developing DAIDS Grade 3/4 TEs; risk was greatest through 24 weeks (6.1%), and decreasing thereafter (>24-48 weeks: 3.4%, >48 weeks-72 weeks: 2.0%, >72-96 weeks: 2.2%), and higher in +LD than -LD patients at each 24-week interval. Treatment with TPV/r, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4⁺ > 200 cells/mm³ at baseline were found to be independent risk factors for development of DAIDS Grade 3/4 TE; the hazard ratios (HR) were 2.8, 2.0, 2.1 and 1.5, respectively. Four of the 144 (2.7%) patients with Grade 3/4 TEs developed hepatic SAEs; overall, 14/1299 (1.1%) patients had hepatic SAEs including six with hepatic failure (0.5%). The K-M risk of developing hepatic SAEs through 96 weeks was 1.4%; highest risk was observed during the first 24 weeks and decreased thereafter; the risk was similar between +LD and -LD patients for the first 24 weeks (0.6% and 0.5%, respectively) and was higher for +LD patients, thereafter.

Conclusion

Through 96 weeks of TPV/r-based cART, DAIDS Grade 3/4 TEs and hepatic SAEs occurred in approximately 11% and 1% of TPV/r patients, respectively; most (84%) had no significant clinical implications and were managed without permanent treatment discontinuation. Among the 14 patients with hepatic SAE, 6 experienced hepatic failure (0.5%); these patients had profound immunosuppression and the rate appears higher among hepatitis co-infected patients. The overall probability of experiencing a hepatic SAE in this patient cohort was 1.4% through 96 weeks of treatment. Independent risk factors for DAIDS Grade 3/4 TEs include TPV/r treatment, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4⁺ > 200 cells/mm³ at baseline.

Trial registration

US-NIH Trial registration number: NCT00144170

Chronic viral hepatitis may diminish the gains of HIV antiretroviral therapy in sub-Saharan Africa

There is a heavy burden of HIV-hepatitis B virus (HBV) and HIV-hepatitis C virus (HCV) co-infection in many regions of the developing world. An often unmentioned illness, issues of poverty, socio-economic status, nutrition, access to medical care, and mistrust of Western-style medicine conspire to reduce the opportunity to receive clinical work-up and treatment for chronic viral hepatitis. We discuss key issues specific to the treatment of viral hepatitis and obstacles to success with this endeavor in the context of HIV co-infection in Africa. We predict that provision of viral hepatitis antiviral therapy will become a more pressing issue as more HIV-infected patients receive lifesaving combination antiretroviral therapy only to succumb thereafter from viral hepatitis-induced liver disease. Given the lessons learned from combination antiretroviral rollout in sub-Saharan Africa, establishing expertise and infrastructure for viral hepatitis care and antiviral therapy is relevant. Failure to act now may diminish the milestones and the gains made with antiretroviral therapy in the developing world.

Management of hepatic complications in HIV-infected persons

In the era of effective antiretroviral therapy (ART), liver disease is the second most common cause of death among persons with human immunodeficiency virus (HIV) infection. Liver disease-related deaths mostly result from chronic infection with hepatitis B virus (HBV) and/or hepatitis C virus (HCV). In addition, recent reports suggest that HCV infection may be transmitted sexually between HIV-infected men who have sex with men. Management of these conditions in HIV-infected persons requires careful consideration, balancing the potential benefits of therapy with the potential for significant treatment-related adverse effects (HCV infection) and viral resistance and/or hepatitis flares (HBV infection). Furthermore, several antiretroviral agents are active against HBV infection, including lamivudine, emtricitabine, tenofovir, and, more recently, entecavir. Despite the complexity and potential for antiretroviral-associated hepatotoxicity, ART usually is safe for patients with viral hepatitis coinfection, and, in some cases, treatment for HIV infection may be beneficial for the liver.

Safety of stavudine in the treatment of HIV infection with a special focus on resource-limited settings

BACKGROUND

Western randomized trials and prospective cohorts in resource-limited settings have proven virological success with stavudine-based highly active antiretroviral therapy. However, stavudine is no longer recommended in first-line treatments in these two settings due to its intrinsic toxicities and side effects. Yet it remains a cornerstone of treatment in resource-limited settings, due to lack of alternatives and its availability in generic fixed-dose combinations.

OBJECTIVE

To review the toxic effects of stavudine and their prevention and management strategies, especially in resource-limited settings.

METHODS

Data from clinical and pharmacological trials in Western countries, as well as prospective cohorts in resource-limited settings, were reviewed.

CONCLUSION

Initiating or switching to less toxic nucleoside analogues whenever possible, or lowering stavudine doses to 30 mg b.i.d., is strongly recommended.

Inflammation and repair in viral hepatitis C

Hepatitis C viral infection (HCV) results in liver damage leading to inflammation and fibrosis of the liver and increasing rates of hepatic decompensation and hepatocellular carcinoma (HCC). However, the host's immune response and viral determinants of liver disease progression are poorly understood. This review will address the determinants of liver injury in chronic HCV infection and the risk factors leading to rapid disease progression. We aim to better understand the factors that distinguish a relatively benign course of HCV from one with progression to cirrhosis. We will accomplish this task by discussion of three topics: (1) the role of cytokines in the adaptive immune response against the HCV infection; (2) the progression of fibrosis; and (3) the risk factors of co-morbidity with alcohol and human immunodeficiency virus (HIV) in HCV-infected individuals. Despite recent improvements in treating HCV infection using pegylated interferon alpha (PEGIFN-alpha) and ribavirin, about half of individuals infected with some genotypes, for example genotypes 1 and 4, will not respond to treatment or cannot be treated because of contraindications. This review will also aim to describe the importance of IFN-alpha-based therapies in HCV infection, ways of monitoring them, and associated complications.

An overview of HIV and chronic viral hepatitis co-infection

Combination antiretroviral therapy often controls HIV disease, may indirectly slow HCV progression, and creates an immune environment which may optimize HCV drug therapy response. Monitoring for antiretroviral-related liver adverse events is vital. However, this complication infrequently causes clinically significant liver toxicity. HCV antiviral therapy should, in most cases, be reserved for those abstaining from alcohol and achieving HIV RNA suppression and immune restoration on combination antiretroviral therapy or for those with nadir CD4 counts above 350 cells/mul. Given the high prevalence of HBV and HCV co-infection, chronic viral hepatitis will influence the health and treatment of HIV-infected individuals for the foreseeable future.

Liver enzymes elevation and immune reconstitution among treatment-naïve HIV-infected patients instituting antiretroviral therapy

OBJECTIVES

Because liver enzymes elevation (LEE) complicates antiretroviral (ARV) therapy, and because the strongest risk factor for ARV-related LEE is HBV/HCV coinfection, it is speculated that ARV-related LEE may be a form of immune reconstitution disease. This study summarizes the relation between immune reconstitution, ARV-induced LEE, and HBV/HCV coinfection.

METHODS

Medical records of ARV-naïve HIV-infected patients initiating ARV were reviewed for hepatitis coinfection, LEE (grade > or =2 AST/ALT) and changes in CD4 T-cell counts over time in an urban HIV clinic. Risk factors for LEE were statistically evaluated, and changes in CD4 T-cell counts were estimated by a mixed-effects linear model.

RESULTS

Predictors of LEE included HBV/HCV coinfection (OR = 6.44) and stavudine use (OR = 2.33). Nelfinavir use was protective (OR = 0.45). The mean rate of change in CD4 T-cell counts was higher in HBV/HCV coinfected subjects who developed LEE (99 cells/microL per month) compared with non-coinfected subjects who did not develop LEE (59 cells/microL per month, P = 0.03), non-coinfected subjects who developed LEE (36 cells/microL per month, P =0.01), and coinfected subjects who did not develop LEE, 38% higher (62 cells/microL per month; P =0.11)

CONCLUSIONS

A more robust immune restoration was observed among HBV/HCV coinfected subjects who developed liver enzyme elevation after antiretroviral initiation compared with other groups. This finding suggests that ARV-related liver enzyme elevation may be related in part to immune reconstitution, as measured by changes in CD4 T-cell counts.

Idiosyncratic drug-induced liver injury: an overview

Drug-induced liver injury (DILI) encompasses a spectrum of clinical disease ranging from mild biochemical abnormalities to acute liver failure. The majority of adverse liver reactions are idiosyncratic, occurring in most instances 5-90 days after the causative medication was last taken. The diagnosis of DILI is clinical, based on history, probability of the suspect medication as a cause of liver injury and exclusion of other hepatic disease. DILI can be hepatocellular (predominant rise in alanine transaminase), cholestatic (predominant rise in alkaline phosphatase) or mixed liver injury. An elevated bilirubin level more than twice the upper limit of normal in patients with hepatocellular liver injury implies severe DILI, with a mortality of approximately 10% and with an incidence rate of 0.7-1.3 per 100,000. Although acute liver failure is rare, 13-17% of all acute liver failure cases are attributed to idiosyncratic drug reactions. Response to drug withdrawal may be delayed up to 1 year with cholestatic liver injury with occasional subsequent progressive cholestasis known as the vanishing bile duct syndrome. Overall, chronic disease may occur in up to 6% even if the offending drug is withdrawn. Antibiotics and NSAIDs are the most common cause of DILI. Statins rarely cause significant liver injury whereas antiretroviral therapy is associated with hepatotoxicity in 10% of treated patients. Multiple mechanisms of DILI have been implicated, including TNF-alpha-activated apoptosis, inhibition of mitochondrial function and neoantigen formation. Risk factors for DILI include age, sex and genetic polymorphisms of drug-metabolising enzymes such as cytochrome P450. In patients with human immunodeficiency virus, the presence of chronic viral hepatitis increases the risk of antiretroviral therapy hepatotoxicity. Over the next decade, the combination of accurate case ascertainment of DILI via clinical networks and the application of genomics and proteomics will hopefully lead to accurate prediction of risk of DILI, so that pharmacotherapy can be optimised with avoidance of adverse hepatic events.

Drug-induced liver injury associated with HIV medications

Antiretroviral therapy (ART) for HIV infection frequently has been associated with elevated liver enzyme levels. Determining the cause of elevated liver enzyme levels in patients who have HIV is difficult because ART usually consists of three different drugs, patients may be taking additional hepatotoxic medications and patients who have HIV often suffer from other liver diseases. Several agents, however, are recognized as having noteworthy and specific patterns of toxicity. This article reviews the different HIV drug classes, incidence of elevated liver enzyme values by class and by individual drug, risk factors, specific toxicities, and possible mechanisms of injury.

Uridine supplementation antagonizes zalcitabine-induced microvesicular steatohepatitis in mice

Zalcitabine is an antiretroviral nucleoside analogue that exhibits long-term toxicity to hepatocytes by interfering with the replication of mitochondrial DNA (mtDNA). Uridine antagonizes this effect in vitro. In the present study we investigate the mechanisms of zalcitabine-induced hepatotoxicity in mice and explore therapeutic outcomes with oral uridine supplementation. BalbC mice (7 weeks of age, 9 mice in each group) were fed 0.36 mg/kg/d of zalcitabine (corresponding to human dosing adapted for body surface), or 13 mg/kg/d of zalcitabine. Both zalcitabine groups were treated with or without Mitocnol (0.34 g/kg/d), a dietary supplement with high bioavailability of uridine. Liver histology and mitochondrial functions were assessed after 15 weeks. One mouse exposed to high dose zalcitabine died at 19 weeks of age. Zalcitabine induced a dose dependent microvesicular steatohepatitis with abundant mitochondria. The organelles were enlarged and contained disrupted cristae. Terminal transferase dUTP nick end labeling (TUNEL) assays showed frequent hepatocyte apoptosis. mtDNA was depleted in liver tissue, cytochrome c-oxidase but not succinate dehydrogenase activities were decreased, superoxide and malondialdehyde were elevated. The expression of COX I, an mtDNA-encoded respiratory chain subunit was reduced, whereas COX IV, a nucleus-encoded subunit was preserved. Uridine supplementation normalized or attenuated all toxic abnormalities in both zalcitabine groups, but had no effects when given without zalcitabine. Uridine supplementation was without apparent side effects.

CONCLUSION

Zalcitabine induces mtDNA-depletion in murine liver with consequent respiratory chain dysfunction, up-regulated synthesis of reactive oxygen species and microvesicular steatohepatitis. Uridine supplementation attenuates this mitochondrial hepatotoxicity without apparent intrinsic effects.

Hepatotoxicity and antiretroviral therapy with protease inhibitors: A review

Highly active antiretroviral therapy including protease inhibitors has led to dramatic decrease in the morbidity and mortality resulting from infection with human immunodeficiency virus-1. However, this combination regimen can be associated with the occurrence of serious toxicities, which may reduce patient compliance. In particular, human immunodeficiency virus-1 protease inhibitors and nevirapine among nonnucleoside reverse transcriptase inhibitors, have the potential for producing hepatotoxicity. We summarise current knowledge of the hepatotoxic effects associated with the commercially available human immunodeficiency virus-1 protease inhibitors based on a literature review of the major retrospective and prospective clinical studies designed to elucidate risk factors for developing hepatotoxicity among human immunodeficiency virus-1-infected patients receiving antiretroviral therapy containing protease inhibitors. Coinfection with chronic hepatitis, a common occurrence in human immunodeficiency virus-1-infected patients, is identified as an independent risk factor for developing hepatotoxicity in antiretroviral-treated human immunodeficiency virus-1-infected patients treated with antiretroviral regimens containing protease inhibitors. The importance of other risk factors for developing protease inhibitor-associated hepatotoxicity and the mechanism underlying the drug-related hepatotoxicity are discussed. The data indicate that the potential for producing hepatotoxicity is variable among the protease inhibitors and suggest that based on differences in drug-related hepatotoxicity, certain protease inhibitors may be preferred for the treatment of human immunodeficiency virus-hepatitis C virus coinfected patients.

Hepatotoxicity of antiretrovirals: incidence, mechanisms and management

One of the toxicities linked to the use of antiretrovirals is the elevation of transaminases. Liver toxicity is a cause of morbidity, mortality, and treatment discontinuation in HIV-infected patients. While several antiretrovirals have been reported to cause fatal acute hepatitis, they most often cause asymptomatic elevations of transaminases. Liver toxicity is more frequent among subjects with chronic hepatitis C and/or B. The incidence of drug-induced liver toxicity is not well known for most antiretrovirals. The contribution of each particular drug to the development of hepatotoxicity in a HAART regimen is difficult to determine. Possible pathogenic mechanisms involved in hepatotoxicity are multiple, including direct drug toxicity, immune reconstitution in the presence of HCV and/or HBV co-infections, hypersensitivity reactions with liver involvement, and mitochondrial toxicity. Other pathogenic pathways may be involved, such as insulin resistance caused by several antiretrovirals, which may contribute to the development of steatohepatitis. The management of liver toxicity is based mainly on its clinical impact, severity and pathogenic mechanism.

Management of HIV Infection in Persons Co-infected With Hepatitis

Co-infection with hepatitis C virus (HCV) and/or hepatitis B virus (HBV) is becoming a rampant disparity in HIV-infected patients. The advent of antiretroviral therapy has led to agents that are effective for suppression of both HIV and HBV; however, this can not be extrapolated to patients who are coinfected with HCV. Treatment of HCV disease is often strenuous and can lead to untoward adverse effects. Co-infection with HIV often leads to higher rates of cirrhosis and liver failure in patients with HBV or HCV, compromising antiretroviral treatment in this patient population due to the hepatotoxicity of these agents. The purpose of this review is to familiarize health care providers to the management of HIV infection in patients who are also co-infected with HBV or HCV.

Therapeutic Interventions for HIV Infection and Chronic Viral Hepatitis

Combination antiretroviral therapy reduces overall and liver-specific morbidity and mortality in coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) and represents the most beneficial pharmaceutical treatment intervention for most coinfected patients. Antiviral therapy for HCV infection is potentially organ- and life-saving but, in general, should be reserved for patients who achieve suppression of HIV RNA and immune restoration from combination antiretroviral therapy or for patients with nadir CD4+ T lymphocyte levels of >350 cells/microL. Safe and virologically active treatment of coinfection with HIV and hepatitis B virus can be concurrently achieved by the use of combination antiretroviral therapy regimens containing lamivudine and/or tenofovir.

Coinfection with HIV and Hepatitis C Virus in Injection Drug Users and Minority Populations

Coinfection with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is common. In the United States, it has been estimated that 25% of persons infected with HIV are also infected with HCV. The prevalence of coinfection with HIV and HCV is highest among those infected via percutaneous routes. In fact, in urban areas in the United States, 50%-90% of persons infected with HIV via injection drug use are coinfected with HCV. In addition, limited data from drug treatment centers in these urban areas suggest that the prevalence of coinfection with HIV and HCV may be highest among African Americans and Hispanics. Little information is available with regard to the epidemiology of coinfection with HIV and HCV among injection drug users (IDUs) or minority populations. Likewise, although there is a growing body of data on the potential complexities of treating HCV among IDUs and the poor response to current anti-HCV treatment among African Americans, few data address the therapy of coinfection with HIV and HCV among IDUs and minority populations.

Liver enzymes elevation after HAART in HIV-HCV co-infection

Hepatitis C virus (HCV) co-infection is common among human immunodeficiency virus (HIV) patients. The incidence and risk factors associated with hepatotoxicity in this population after high active antiretroviral therapy (HAART) is initiated are still not well-understood. We argued to evaluate the incidence and risk factors associated with liver enzyme elevation (LEE) and their clinical significance. A retrospective chart review of patients who started HAART and had follow up at our centre for at least 1 year was undertaken. The frequency and severity of alanine aminotransferase (ALT)/aspartate aminotransferase (AST) elevation after treatment initiation were investigated and searched for clinical manifestations. Between January 1996 and March 2002, 85 HIV-HCV co-infected patients began HAART and continued follow up for at least 1 year. The incidence of severe toxicity [grades 3 + 4 LEE: >5 and >10 times the upper limit of normal (ULN) of ALT or AST] was calculated at 4% per person-years. There were no clinical manifestations of liver toxicity, and patients continued their treatment with a trend towards a decrease of their enzymes. No statistical differences in opportunistic infections or mortality were evident. The variables associated with severe hepatotoxicity were a higher baseline AST, higher international normalized ratio (INR) and lower albumin. A baseline AST < 2.1 ULN had a negative predictive value of 92% of leading to severe hepatotoxicity. In HIV-HCV co-infected patients therefore, the group at a higher risk of developing higher transaminase elevations is the one with a higher baseline AST, higher INR and lower albumin.

Hepatotoxicity and nelfinavir: a meta-analysis

BACKGROUND & AIMS

The inclusion of protease inhibitors in 3-drug highly active antiretroviral regimens for treating patients who are infected with human immunodeficiency virus-1 has had a significant impact in increasing survival and decreasing morbidity. However, the effectiveness of this class of drugs may be compromised by the occurrence of drug-related hepatotoxicity, which is problematic especially in individuals co-infected with hepatitis viruses. Based on its clinical and pharmacologic profile, especially its unique pattern of resistance, nelfinavir has been used frequently as a first-line protease-inhibitor therapy for human immunodeficiency virus-1-infected patients. The aim of this study was to identify the relative potential for developing hepatotoxicity for nelfinavir vs other protease inhibitors.

METHODS

An exploratory meta-analysis of liver enzyme level increases was conducted in a combined total of 4268 patients derived from 3 large recently conducted prospective and retrospective clinical trials and a prospective cohort study.

RESULTS

The results indicate that among 4 commercially available protease inhibitors and a 2-protease inhibitor combination, nelfinavir and indinavir are associated with the lowest rates of occurrence of severe hepatotoxicity (ie, combined estimates of liver enzyme level increases of 2.9% and 3.1%, respectively). The low rate of occurrence of severe hepatotoxicity for nelfinavir was shown even among patients co-infected with hepatitis viruses.

CONCLUSIONS

In conclusion, these data provide support for the conclusion that differences in the potential for hepatotoxicity do exist among the commercially available protease inhibitors.

Therapies for HIV and viral hepatitis coinfection

The natural history of chronic viral hepatitis is altered by HIV coinfection. Liver fibrosis rates and clinical features of liver disease develop more rapidly. Although HIV-hepatitis C virus coinfected subjects may progress more rapidly to AIDS, this is probably explained by comorbid illness, substance abuse and socioeconomic circumstances. Safe and virologically active treatment of HIV-hepatitis B virus coinfection can be concurrently achieved by the use of highly active antiretroviral therapy regimens containing lamivudine and/or tenofovir. In most cases, highly active antiretroviral therapy represents the most beneficial initial pharmaceutical intervention for HIV-hepatitisC virus coinfection. HepatitisC virus antiviral therapy should, in most cases, be reserved for those achieving HIV RNA suppression and immune restoration from highly active antiretroviral therapy or with nadir CD4 T-lymphocytes above 350 cells/microl.

Hepatitis C coinfection increases the risk of fulminant hepatic failure in patients with HIV in the HAART era

BACKGROUND/AIMS

It is uncertain if patients coinfected with hepatitis C and HIV are more likely to suffer fulminant hepatic failure (FHF) when compared to patients with HIV-only.

METHODS

We conducted a retrospective cohort study using national administrative databases from the Department of Veterans Affairs in patients hospitalized for the first time with HIV and/or hepatitis C between 10/1991 and 9/2000. Fulminant hepatic failure was defined as occurring after the index hospitalization through 9/2001 in the absence of pre-existing liver disease. We calculated incidence rates, Kaplan Meier cumulative incidence curves, and Cox proportional hazards ratios while adjusting for demographics and other potential confounders.

RESULTS

We identified 11,678 patients with HIV-only and 4761 patients with coinfection. There were 92 cases of fulminant hepatic failure yielding an incidence rate of 1.1/1000 person-years and 2.5/1000 person-years in the HIV-only and coinfected groups. The cumulative incidence of fulminant hepatic failure in the coinfected group was higher than in the HIV-only group (P<0.0001). The risk of fulminant hepatic failure in patients with coinfection compared to HIV-only during the HAART era was several folds higher than that during the pre-HAART era.

CONCLUSIONS

HAART and hepatitis C coinfection appeared to act synergistically in HIV-infected patients to increase the risk of fulminant hepatic failure, a rare but often fatal disease.

Hepatotoxicity of Antiretrovirals

Hepatotoxicity is a relevant adverse effect derived from the use of antiretrovirals that may increase the morbidity and mortality among treated HIV-infected patients and challenges the treatment of HIV infection. Although several antiretrovirals have been reported to cause fatal acute hepatitis, they most often cause an asymptomatic elevation of transaminase levels. In addition to ruling out a variety of processes not related to the use of antiretrovirals or to the HIV infection, for appropriate management of the complication it is necessary to deduce the possible pathogenic mechanisms of the hepatotoxicity. Among these mechanisms, direct drug toxicity, immune reconstitution in the presence of hepatitis C virus (HCV) and/or hepatitis B virus (HBV) co-infections, hypersensitivity reactions with liver involvement and mitochondrial toxicity play a major role, although several other pathogenic pathways may be involved. Liver toxicity is more frequent among subjects with chronic HCV and/or HCB co-infections and alcohol users. Complex immune changes that alter the response against hepatitis virus antigens might be involved in the elevation of transaminase levels after suppression of the HIV replication by highly active antiretroviral therapy (HAART) in patients co-infected with HCV/HBV. The contribution of each particular drug to the development of hepatotoxicity in a HAART regimen is difficult to determine. The incidence of liver toxicity is not well known for most of the antiretrovirals. Although it is most often mild, fatal cases of acute hepatitis linked to the use of HAART have been reported across all families of antiretrovirals. Acute hepatitis is related to hypersensitivity reactions in the case of non-nucleosides and to mitochondrial toxicity in the case of nucleoside analogues. Alcohol intake and use of other drugs are other co-factors that increase the incidence of transaminase level elevation among HIV-infected patients. The management of liver toxicity is based mainly on its clinical impact, severity and pathogenic mechanism. Although low-grade HAART-related hepatotoxicity most often spontaneously resolves, severe grades may require discontinuation of the antiretrovirals, for example when there is liver decompensation, hypersensitivity reaction or lactic acidosis.

Hepatotoxicity associated with protease inhibitor-based antiretroviral regimens with or without concurrent ritonavir

OBJECTIVE

To determine the incidence of significant liver enzyme elevations following the initiation of protease inhibitor (PI)-based antiretroviral therapy (ART) with or without pharmacokinetic boosting with ritonavir (RTV), and to define the role of chronic viral hepatitis in its development.

DESIGN

Prospective, cohort analysis of 1161 PI-naive, HIV-infected patients receiving RTV-boosted (lopinavir, indinavir and saquinavir) and unboosted PI-based ART (indinavir, nelfinavir) that had at least one liver enzyme measurement before and during therapy.

METHODS

The incidence of grade 3 and 4 liver enzyme elevations among persons with and without hepatitis B and/or C co-infection treated with PI-based ART were compared. Severe hepatotoxicity was defined as an increase in serum liver enzyme >/= 5-times the upper limit of the normal range or 3.5-times an elevated baseline level.

RESULTS

The incidence of grade 3 or 4 elevations among PI-naive patients was: nelfinavir, 11%; lopinavir/RTV (200 mg/day), 9%; indinavir, 13%; indinavir/RTV (200-400 mg/day), 12.8%; and saquinavir/RTV (800 mg/day), 17.2%. The risk was significantly greater among persons with chronic viral hepatitis (63% of cases); however, the majority of hepatitis C virus (HCV)-infected patients treated with nelfinavir (84%), saquinavir/RTV (74%), indinavir, 86%, indinavir/RTV (90%) or lopinavir/RTV (87%) did not develop hepatotoxicity.

CONCLUSIONS

Our data suggest that the lopinavir/RTV is not associated with a significantly increased risk of hepatotoxity among HCV-infected and uninfected patients compared with an alternative PI-based regimen, nelfinavir. Accordingly, other medication-related factors (e.g, efficacy and non-hepatic toxicity) should guide individual treatment decisions.

The management of chronic viral hepatitis: A Canadian consensus conference 2004

Several government and nongovernment organizations held a consensus conference on the management of acute and chronic viral hepatitis to update previous management recommendations. The conference became necessary because of the introduction of new forms of therapy for both hepatitis B and hepatitis C. The conference issued recommendations on the investigation and management of chronic hepatitis B, including the use of lamivudine, adefovir and interferon. The treatment of hepatitis B in several special situations was also discussed. There were also recommendations on the investigation and treatment of chronic hepatitis C and hepatitis C-HIV coinfection. In addition, the document makes some recommendations about the provision of services by provincial governments to facilitate the delivery of care to patients with hepatitis virus infection. The present document is meant to be used by practitioners and other health care providers, including public health staff and others not directly involved in patient care.

Lopinavir/ritonavir treatment in HIV antiretroviral-experienced patients: evaluation of risk factors for liver enzyme elevation

OBJECTIVES

To evaluate the risk factors for lopinavir/ritonavir (LPV/r)-related liver enzyme elevation (LEE) in HIV antiretroviral-experienced patients.

METHODS

An open prospective observational study was carried out to analyse the incidence and time of LEE development during LPV/r treatment, and to determine whether LEE development was correlated with epidemiological, clinical and biochemical data, immune and virological profiles, concomitant hepatic diseases, antiretroviral therapy, or histological and ultrasonography liver examination results. A diagnosis of LEE was considered when LEE symptoms occurred after LPV/r introduction and was confirmed by a second control within 2 weeks.

RESULTS

A total of 782 HIV-positive outpatients have been enrolled in six different Infectious Diseases Departments in Northern Italy since August 2000. Of these patients, 71 (9.1%) developed LEE within 115+/-85 days (mean+/-standard deviation); 13 of these subjects discontinued LPV/r and four were hospitalized. Of the patients with LEE, 74.6% and 25.4% had grade 2 and > or =3 toxicity, respectively. No correlation between LEE and sex, baseline CD4 cell count, viral load, HIV stage, triglyceride values, histological and ultrasonography liver examination results, nevirapine use, or increase in CD4 cell count was observed. Higher baseline alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) values (P < 0.0001 and P=0.004, respectively), younger age (P=0.008), previous hepatitis B virus (HBV) infection (P=0.012), efavirenz use (P=0.04), and hepatitis C virus (HCV) and/or HBV coinfection (P < 0.0001, relative risk 4.78) were significantly related to LEE. No correlations between LEE and the same risk factors as investigated in the whole study population were found in subgroups of patients with HCV and/or HBV infection.

CONCLUSIONS

HCV and HBV testing and measurement of baseline ALT values are essential for screening subjects at risk of LEE before starting LPV/r. Strict monitoring of clinical and biochemical parameters should be performed in these patients.

Treatment of the hepatitis C virus in patients coinfected with HIV

Hepatitis C virus (HCV) coinfection is common among individuals with HIV, and the progression of liver disease is accelerated in coinfected individuals compared with those with HCV alone. HCV coinfection also can decrease tolerability of highly active antiretroviral therapy. Additionally, the presence of HCV appears to increase morbidity and mortality in these individuals, and as such the management of both HCV and HIV in coinfected individuals requires careful consideration. Although coinfected patients should be considered for HCV therapy, the limited information to date indicates a lower rate of virologic response with current HCV therapies. Moreover, interactions between HCV and HIV antiviral medications may occur and potentially affect treatment efficacy. Thus, the decision to undertake HCV treatment must be individualized.

The Problems Faced When Assessing the Prevalence and Incidence of Antiretroviral-Related Toxicities

Although the dramatic effect of highly active antiretroviral therapy (HAART) in reducing morbidity and mortality must not be underestimated, it is also important to consider the incidence and prevalence of HAART-related toxicities. Although several studies have investigated HAART-related toxicities, there has been great variety between them in the reported incidence and prevalence rates of these toxicities. Various factors, including whether the study type was a clinical trial or an observational study, the definition of the toxicity endpoints, the demographic characteristics of the study populations and the effect of calendar year on analyses, may all influence the rates observed. We investigated the possible explanations for the differences in the incidence and prevalence rates of HAART-related toxicities between studies, focussing on metabolic and hepatotoxic disorders.

HIV and hepatitis C coinfection within the CAESAR study

The declining incidence of AIDS-related opportunistic diseases among people with HIV infection has shifted the focus of clinical management to prevention and treatment of comorbidities such as chronic liver disease. The increased risk of hepatitis C virus (HCV)-related advanced liver disease in people with HIV infection makes early HCV diagnosis a priority. To assess HCV prevalence and predictors of HIV/HCV coinfection, we have conducted a retrospective analysis of people enrolled in the CAESAR (Canada, Australia, Europe, South Africa) study, a multinational randomized placebo-controlled study of the addition of lamivudine to background antiretroviral therapy. The impact of HCV on HIV disease progression was also examined. Anti-HCV antibody testing on 1649 CAESAR study participants demonstrated a HIV/HCV coinfection prevalence of 16.1%, which varied from 1.9% in South Africa to 48.6% in Italy. The strongest predictor of HIV/HCV coinfection was HIV exposure category (P<0.0001), with odds ratios (ORs) compared to homosexual as follows: injecting drug use (IDU), 365 [95% confidence interval (CI): 179-742]; transfusion or blood products, 32.2 (95% CI: 15.2-67.6); homosexual and IDU, 22.9 (95% CI: 8.5-62.1). The prevalence of HIV/HCV was low (3.7%) among homosexual men without reported IDU. Other predictors of HIV/HCV coinfection were alanine aminotransferase (ALT), country of residence, ethnicity and stage of HIV disease. A history of IDU or ALT > or =40 U/L at baseline had a positive predictive value (PPV) of 35%, negative predictive value (NPV) of 96%, sensitivity of 82% and specificity of 71% for HIV/HCV coinfection. HIV disease progression was similar in HIV monoinfected and HIV/HCV coinfected patients. People with HIV and a history of IDU or elevated liver function tests should be targeted for HCV testing. The low prevalence of HIV/HCV coinfection among homosexual men without a history of IDU suggests low efficiency of sexual HCV transmission.

Pitfalls of assessing hepatotoxicity in trials and observational cohorts

The relationship between the use of antiretroviral drugs and the development of hepatic abnormalities has been documented in both randomized controlled trials (RCTs) and observational database studies. Both types of study design are known to have limitations when addressing this issue. Whereas RCTs may enroll a population that is at lower risk for the development of hepatotoxicity, thus underestimating the possible effect of antiretroviral therapy on hepatic abnormalities, observational databases may encompass information from a more heterogeneous group of patients, allowing the drugs to be assessed in a more realistic situation. However, a number of possible biases associated with the use of observational data may limit the conclusions that can be drawn from such studies. I describe some of the benefits and limitations of RCTs and observational data sets when drawing conclusions about the relationship between antiretroviral therapy and the development of hepatic abnormalities.

Drug-Induced Liver Injury Associated with Antiretroviral Therapy that Includes HIV-1 Protease Inhibitors

Since their introduction, hepatotoxicity has been associated with the use of human immunodeficiency virus (HIV)-1 protease inhibitors (PIs). However, the complexity of the HIV-infected patient and the combinations of medications used to treat HIV complicate the understanding of the independent effects of PIs in the development of drug-induced liver injury (DILI). I discuss the current understanding of PI-associated hepatotoxicity. Of the PI regimens studied, the greatest risk of DILI has been observed among patients receiving full-dose ritonavir. Similarly, hepatitis B and/or C virus coinfection has been associated with a greater risk of DILI, compared with those with no hepatitis. Although the specific mechanism by which viral hepatitis increases this risk is not known, patients with cirrhosis may have decreased cytochrome P450 activity, leading to increased PI exposure. Clearly, further research is needed to define the interaction of PIs and chronic viral hepatitis in the development of DILI.

Drug- and chemical-induced cholestasis

Cholestasis caused by medicinal and chemical agents is an increasingly well-recognized cause of liver disease. Clinical drug-induced cholestatic syndromes producing jaundice and bile duct injury can mimic extrahepatic biliary obstruction, primary biliary cirrhosis, and sclerosing cholangitis, among others. This article updates the various forms of drug-induced cholestasis, focusing on the clinicopathologic features of this form of hepatic injury and on the known or putative mechanisms by which drugs and chemicals lead to cholestasis.

Cholestasis in HIV-infected patients

Cholestasis is frequently observed in the HIV-infected population and can be caused by drugs, such as highly active antiretroviral therapy (HAART) and antimicrobial agents, and by opportunistic infections of the liver. Less common causes such as HIV-related malignancies or biliary tract disease are also encountered. Most disorders respond to medical management, but patient outcome was often dictated by the stage of the HIV infection and concomitant illnesses in the pre-HAART era. Prompt recognition and specific treatment may improve the outcome for these patients in the HAART era.

SARS-associated viral hepatitis caused by a novel coronavirus: report of three cases

Liver impairment is commonly reported in up to 60% of patients who suffer from severe acute respiratory syndrome (SARS). Here we report the clinical course and liver pathology in three SARS patients with liver impairment. Three patients who fulfilled the World Health Organization case definition of probable SARS and developed marked elevation of alanine aminotransferase were included. Percutaneous liver biopsies were performed. Liver specimens were examined by light and electron microscopy, and immunohistochemistry. Reverse-transcriptase polymerase chain reaction (RT-PCR) using enhanced real-time PCR was applied to look for evidence of SARS-associated coronavirus infection. Marked accumulation of cells in mitosis was observed in two patients and apoptosis was observed in all three patients. Other common pathologic features included ballooning of hepatocytes and mild to moderate lobular lymphocytic infiltration. No eosinophilic infiltration, granuloma, cholestasis, fibrosis, or fibrin deposition was noted. Immunohistochemical studies revealed 0.5% to 11.4% of nuclei were positive for proliferative antigen Ki-67. RT-PCR showed evidence of SARS-associated coronavirus in the liver tissues, but not in the sera of all 3 patients. However, electron microscopy could not identify viral particles. No giant mitochondria, micro- or macro-vesicular steatosis was observed. In conclusion, hepatic impairment in patients with SARS is due to SARS-associated coronavirus infection of the liver. The prominence of mitotic activity of hepatocytes is unique and may be due to a hyperproliferative state with or without disruption of cell cycle by the coronavirus. With better knowledge of pathogenesis, specific therapy may be targeted to reduce viral replication and modify the disease course.

SARS-associated viral hepatitis caused by a novel coronavirus: report of three cases

Liver impairment is commonly reported in up to 60% of patients who suffer from severe acute respiratory syndrome (SARS). Here we report the clinical course and liver pathology in three SARS patients with liver impairment. Three patients who fulfilled the World Health Organization case definition of probable SARS and developed marked elevation of alanine aminotransferase were included. Percutaneous liver biopsies were performed. Liver specimens were examined by light and electron microscopy, and immunohistochemistry. Reverse-transcriptase polymerase chain reaction (RT-PCR) using enhanced real-time PCR was applied to look for evidence of SARS-associated coronavirus infection. Marked accumulation of cells in mitosis was observed in two patients and apoptosis was observed in all three patients. Other common pathologic features included ballooning of hepatocytes and mild to moderate lobular lymphocytic infiltration. No eosinophilic infiltration, granuloma, cholestasis, fibrosis, or fibrin deposition was noted. Immunohistochemical studies revealed 0.5% to 11.4% of nuclei were positive for proliferative antigen Ki-67. RT-PCR showed evidence of SARS-associated coronavirus in the liver tissues, but not in the sera of all 3 patients. However, electron microscopy could not identify viral particles. No giant mitochondria, micro- or macro-vesicular steatosis was observed. In conclusion, hepatic impairment in patients with SARS is due to SARS-associated coronavirus infection of the liver. The prominence of mitotic activity of hepatocytes is unique and may be due to a hyperproliferative state with or without disruption of cell cycle by the coronavirus. With better knowledge of pathogenesis, specific therapy may be targeted to reduce viral replication and modify the disease course.

Acute liver enzyme elevations in HIV-1-infected patients

BACKGROUND

Acute liver enzyme elevations (ALEE) have been associated with a first-line highly active antiretroviral therapy (HAART) and/or viral hepatitis coinfections in HIV-infected patients. By comparison, the frequency and the risk factors of ALEE in untreated patients and in patients treated with several antiretroviral regimens need to be assessed.

PURPOSE

To describe the long-term frequency and the characteristics of ALEE in antiretroviral treated and untreated patients and to define risk factors for ALEE in a retrospective cohort of HIV-1-infected patients.

METHOD

An HIV-infected cohort was retrospectively examined. ALEE was defined as levels of alanine amino transferase and/or alkaline phosphatase rising to at least 2.5 times above baseline values. Hazard ratios (HR) for ALEE were estimated using an extension of the Cox proportional model taking into account recurrent events.

RESULTS

Out of 239 assessable patients, 12 (5%) were coinfected with hepatitis B virus (HBV) and 34 (14.2%) with hepatitis C virus (HCV). The incidence rate of ALEE was 9.9/100 patients-year and the cumulative incidence was 20.9%. HCV genotype 3 tended to give a higher risk of ALEE. Independent factors for developing ALEE in multivariate logistic regression were HBV (HR = 4.0) and HCV (HR = 3.4) coinfections, antiretroviral therapy (HR = 2.6), CDC stage C (HR = 2.5), and high alkaline phosphatase baseline values (HR = 1.7).

CONCLUSION

The occurrence of ALEE is influenced more by the past medical history and the clinical background of the patients than by antiretroviral therapy. These patient-linked variables must be taken into account to avoid unwarranted treatment withdrawal.