Human immunodeficiency virus and liver disease forum 2010: conference proceedings

Liver Disease in Human Immunodeficiency Virus Infection

Liver disease in human immunodeficiency virus (HIV) remains a main cause of morbidity and mortality. Liver-related morbidity and mortality can be caused by multiple etiologic factors, including opportunistic infections, direct and indirect effects of antiretrovirals, direct and indirect effects of HIV, and viral hepatitides. These factors present with varied liver pathophysiologic mechanisms that lead to abnormalities in liver enzymes and synthetic function test, followed by distinct clinical presentations. This article elucidates the direct effects on HIV in the liver and explores the diagnostic and management challenges in patients with HIV in the era of highly active antiretroviral treatment.

Solid organ transplantation in the HIV-infected patient: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the management of transplantation in HIV-infected individuals. Transplantation has become the standard of care for patients with HIV and end-stage kidney or liver disease. Although less data exist for thoracic organ and pancreas transplantation, it is likely that transplantation is also safe and effective for these recipients as well. Despite what is typically a transient decline in CD4⁺ T lymphocytes, HIV remains well controlled and infection risks are similar to those of HIV-uninfected transplant recipients. The availability of effective directly active antivirals for the treatment of Hepatitis C is likely to improve outcomes in HIV and HCV co-infected individuals, a population previously noted to have decreased survival. Drug interactions remain an important consideration, and integrase inhibitor-based regimens are preferred due to the absence of interactions with calcineurin and mTOR inhibitors. Additionally, despite the use of more potent immunosuppression, rejection rates exceed those found in HIV-uninfected recipients. Ongoing research evaluating HIV-positive organ donors may provide support for utilizing these donors for HIV-positive patients in need of transplantation.

Reproductive Aging and Hepatic Fibrosis Progression in Human Immunodeficiency Virus/Hepatitis C Virus-Coinfected Women

BACKGROUND

Severity of hepatic fibrosis is greater in postmenopausal than in premenopausal women, perhaps owing to protective effects of estrogens. However, prior studies of estrogen and liver fibrosis lack serial fibrosis measures, adjustment for age, or longitudinal observations in coinfected populations.

METHODS

In a longitudinal cohort of women coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV), we assessed fibrosis progression across reproductive age, using validated serum fibrosis markers, aminotransferase platelet ratio index (APRI) and fibrosis 4 (FIB-4). Fibrosis rate was evaluated within each woman as she transitioned from pre- to postmenopause, defined by a biomarker of ovarian function.

RESULTS

The median follow-up (n = 405) was 9.1 years (interquartile range, 5.0-15.2 years), with a median menopausal age of 49 years (47-52 years). When fully controlled for chronologic aging, the fibrosis progression rate was accelerated during perimenopause, as shown using FIB-4 (0.12 units per year faster than during premenopause; 95% confidence interval [CI], .02-.21; P = .01) and APRI (0.05 units per year faster; -.002 to .09; P = .06). Accelerated fibrosis was also observed during postmenopause compared with premenopause, for FIB-4 (0.14 units per year faster; 95% CI, -.01 to .29; P = .07) and APRI (0.07 units per year faster; -.003 to .15; P = .06). Accelerated fibrosis in perimenopause persisted after adjustment for Hispanic ethnicity, antiretroviral use, and alcohol (0.10 FIB-4 units per year faster than during premenopause; 95% CI, .008-.20; P = .03).

CONCLUSIONS

In HIV/HCV-coinfected women, hepatic fibrosis accelerates with reproductive aging. Accelerated fibrosis begins in perimenopause, highlighting a previously unrecognized group of women at increased risk for advanced fibrosis and associated complications. Longitudinal analyses of fibrosis rates across reproductive age should be conducted in non-HCV-related liver diseases, given potential implications in a broader spectrum of women.

Mechanisms of Accelerated Liver Fibrosis Progression during HIV Infection

With the introduction of antiretroviral therapy (ART), a dramatic reduction in HIV-related morbidity and mortality has been observed. However, it is now becoming increasingly clear that liver-related complications, particularly rapid fibrosis development from ART as well as from the chronic HIV infection itself, are of serious concern to HIV patients. The pathophysiology of liver fibrosis in patients with HIV is a multifactorial process whereby persistent viral replication, and bacterial translocation lead to chronic immune activation and inflammation, which ART is unable to fully suppress, promoting production of fibrinogenic mediators and fibrosis. In addition, mitochondrial toxicity, triggered by both ART and HIV, contributes to intrahepatic damage, which is even more severe in patients co-infected with viral hepatitis. In recent years, new insights into the mechanisms of accelerated fibrosis and liver disease progression in HIV has been obtained, and these are detailed and discussed in this review.

MECHANISMS OF INTERACTION OF VIRAL CAUSATIVE AGENTS IN PATIENTS CO-INFECTED WITH HUMAN IMMUNODEFICIENCY AND HEPATITIS C VIRUSES

In patients infected with human immunodeficiency virus (HIV) in 20 - 30% of cases co-infection with hepatitis C virus (HCV) is observed, that is associated with common routes of transmission for these causative agents. The main cause of lethal outcome for co-infected patients is liver damage. Thus, analysis of mechanisms of mutual influence of HIV and HCV under the conditions of co-infection gains special attention, that can be examined from both standpoints of direct inter-molecular interaction of 2 viral causative agents, as well as from the position of their immune-mediated effect. Negative effect of HIV on the course of fibrosis process in liver during HCVinfection is associated with the feature of this virus to cause deep alteration in the immune system by direct damage of CD4+ cells, disruption of mechanisms of immunological memory, suppression of functions of liver fraction of NK and NKT, as well as its ability of co-receptor interaction with hepatocytes and stellate cells, enhancing progress of fibrosis alterations and HCV replication in liver. HCV is also established to effect replication of HIV, stimulate infection of macrophages with this virus. All these events facilitate the rise in lethality during HIV and HCV co-infection.

Liver fibrosis in human immunodeficiency virus/hepatitis C virus coinfection: Diagnostic methods and clinical impact

Several non-invasive surrogate methods have recently challenged the main role of liver biopsy in assessing liver fibrosis in hepatitis C virus (HCV)-monoinfected and human immunodeficiency virus (HIV)/HCV-coinfected patients, applied to avoid the well-known side effects of liver puncture. Serological tests involve the determination of biochemical markers of synthesis or degradation of fibrosis, tests not readily available in clinical practice, or combinations of routine tests used in chronic hepatitis and HIV/HCV coinfection. Several radiologic techniques have also been proposed, some of which commonly used in clinical practice. The studies performed to compare the prognostic value of non-invasive surrogate methods with that of the degree of liver fibrosis assessed on liver tissue have not as yet provided conclusive results. Each surrogate technique has shown some limitations, including the risk of over- or under-estimating the extent of liver fibrosis. The current knowledge on liver fibrosis in HIV/HCV-coinfected patients will be summarized in this review article, which is addressed in particular to physicians involved in this setting in their clinical practice.

Modulation of HCV replication after combination antiretroviral therapy in HCV/HIV co-infected patients

The hepatitis C virus (HCV) is an important contributor to morbidity and mortality in patients co-infected with HIV. Co-infection results in increased HCV replication and more rapid rates of liver disease progression. The effect of HIV combination antiretroviral therapy (cART) on HCV replication has not been studied in depth. To address this issue, we enrolled a small cohort of HCV/HIV co-infected patients into a cART initiation trial and used dynamic modeling combined with evaluation of immune responses and microarray profiles to determine how effective treatment of HIV affects HCV. Treatment with cART resulted in increased HCV replication and increased alanine aminotransferase (ALT) in a subset of patients. Subjects with evidence of hepatic injury (increased ALT) were more likely to have HCV-specific immune responses directed against HCV epitopes. Over time, HCV viral loads declined. Reproducible and biologically important gene expression changes occurred in co-infected patients who underwent successful cART. The effective suppression of HIV by cART initiated a cascade of early and late events in treated patients. Early events involving down-regulation of interferon-stimulated genes may have led to transiently increased viral replication and hepatic injury. At later time points, HCV viral load declined to levels comparable to those seen in the setting of HCV monoinfection. These findings support early antiretroviral therapy in those with HCV/HIV co-infection.

Combination lamivudine and adefovir versus entecavir for the treatment of naïve chronic hepatitis B patients: a pilot study

BACKGROUND

The aim of this study was to compare the effect of combination lamivudine (LAM) and adefovir dipivoxil (ADV) versus entecavir (ETV) monotherapy for naïve HBeAg-positive chronic hepatitis B (CHB) patients.

MATERIAL/METHODS

Fifty enrolled patients with CHB were evenly divided into 2 groups: a group treated with of lamivudine (LAM) (100 mg/day) plus adefovir (ADV) (10 mg/day) combination, and a group treated with entecavir (ETV) (0.5 mg/day). Serum levels of ALT, AST, creatinine, bilirubin, HBsAg, HBeAg and HBV viral load, and genotypic resistance were analyzed at 0, 12, 24, 52, and 104 weeks. HBV DNA levels were determined by real-time PCR and HBsAg and HBeAg by chemiluminescence. Serum levels of ALT, AST, creatinine, and bilirubin were measured by an automatic biochemical analyzer. Data analysis was performed with SPSS 12.0 software.

RESULTS

There were no significant differences in the virological response (VR) rates between LAM+ADV and ETV cohorts at 24, 52, and 104 weeks (P>0.05). The HBeAg seroconversion rates were 28% and 20%, and the biochemical response (BR) rates were 88% and 84% at week 104 in the LAM+ADV and ETV groups, respectively. The rates of undetectable HBV DNA, HBeAg seroconversion, and ALT normalization rates were similar in both cohorts. No virological breakthrough or serious adverse effects were noted for any patient during the study period.

CONCLUSIONS

Both LAM+ADV combination therapy and ETV monotherapy were effective and safe in the treatment of -naïve HBeAg-positive CHB patients. However, further studies are needed to obtain long-term results.

Pathogenesis of accelerated fibrosis in HIV/HCV co-infection

Human immunodeficiency virus (HIV) infection is a major cause of acceleration of hepatitis C virus-related liver disease, cirrhosis, and death. However, studies of liver disease pathogenesis in HIV/HCV coinfection have thus far been limited. Emerging data support multiple derangements attending HIV coinfection, including increases in profibrogenic cytokine expression and secretion, generation of enhanced oxidative stress, and increases in hepaotcyte apoptosis. These derangements may be further augmented in the presence of increased microbial translocation in the setting of HIV disease. New insight into the mechanisms of HIV/HCV pathogenesis causing accelerated liver fibrosis could lead to new therapeutic strategies designed to retard ths process.

Hepatitis C and HIV co-infection: new drugs in practice and in the pipeline

HCV/HIV coinfection continues to represent a serious health issue with risk of liver disease progression and development of hepatocellular carcinoma. Pegylated interferon with ribavirin is approved for treatment but results are suboptimal and tolerability poor. First-generation HCV protease inhibitors appear to significantly improve HCV treatment response in the setting of HIV infection. Interactions with HIV protease inhibitors have been documented, but the significance of this in terms of adverse reactions and HCV or HIV viral breakthrough remains uncertain. Next generation agents hold the promise of even better efficacy, with improved dosing schedules and perhaps decreased risk of drug:drug interactions.

Drug-drug interactions between antiretroviral and immunosuppressive agents in HIV-infected patients after solid organ transplantation: a review

Since the introduction of combination antiretroviral therapy (cART) resulting in the prolonged survival of HIV-infected patients, HIV infection is no longer considered to be a contraindication for solid organ transplantation (SOT). The combined management of antiretroviral and immunosuppressive therapy proved to be extremely challenging, as witnessed by high rates of allograft rejection and drug toxicity, but the profound drug-drug interactions between immunosuppressants and cART, especially protease inhibitors (PIs) also play an important role. Caution and frequent drug level monitoring of calcineurin inhibitors, such as tacrolimus are necessary when PIs are (re)introduced or withdrawn in HIV-infected recipients. Furthermore, the pharmacokinetics of glucocorticoids and mTOR inhibitors are seriously affected by PIs. With the introduction of integrase inhibitors, CCR5-antagonists and fusion inhibitors which cause significantly less pharmacokinetic interactions, have minor overlapping toxicity, and offer the advantage of pharmacodynamic synergy, it is time to revaluate what may be considered the optimal antiretroviral regimen in SOT recipients. In this review we provide a brief overview of the recent success of SOT in the HIV population, and an update on the pharmacokinetic and pharmacodynamic interactions between currently available cART and immunosuppressants in HIV-infected patients, who underwent SOT.

Challenges for HCV vaccine development in HIV-HCV coinfection

It is estimated that 4-5 million HIV-infected patients are coinfected with HCV. The impact of HIV on the natural course of HCV infection is deleterious. This includes a higher rate of HCV persistence and a faster rate of fibrosis progression. Coinfected patients show poor treatment outcome following standard HCV therapy. Although direct antiviral agents offer new therapeutic options, their use is hindered by potential drug interactions and toxicity in HIV-infected patients under HAART. Overtime, a large reservoir of HCV genotype 1 patients will accumulate in resource poor countries where the hepatitis C treatment is not easily affordable and HIV therapy remains the primary health issue for coinfected individuals. HCV vaccines represent a promising strategy as an adjunct or alternative to current HCV therapy. Here, the authors review the pathogenesis of hepatitis C in HIV-infected patients, with a focus on the impact of HIV on HCV-specific immune responses and discuss the challenges for vaccine development in HIV-HCV coinfection.