Human Immunodeficiency Virus Infection, Antiretroviral Therapy, and Liver Pathology

NNRTI and Liver Damage: Evidence of Their Association and the Mechanisms Involved

Due to the improved effectiveness and safety of combined antiretroviral therapy, human immunodeficiency virus (HIV) infection has become a manageable, chronic condition rather than a mortal disease. However, HIV patients are at increased risk of experiencing non-AIDS-defining illnesses, with liver-related injury standing out as one of the leading causes of death among these patients. In addition to more HIV-specific processes, such as antiretroviral drug-related toxicity and direct injury to the liver by the virus itself, its pathogenesis is related to conditions that are also common in the general population, such as alcoholic and non-alcoholic fatty liver disease, viral hepatitis, and ageing. Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are essential components of combined anti-HIV treatment due to their unique antiviral activity, high specificity, and acceptable toxicity. While first-generation NNRTIs (nevirapine and efavirenz) have been related largely to liver toxicity, those belonging to the second generation (etravirine, rilpivirine and doravirine) seem to be generally safe for the liver. Indeed, there is preclinical evidence of rilpivirine being hepatoprotective in different models of liver injury, independently of the presence of HIV. The present study aims to review the mechanisms by which currently available anti-HIV drugs belonging to the NNRTI family may participate in the development of liver disease.

Mechanistic insights into antiretroviral drug-induced liver injury

All classes of antiretroviral therapy (ART) have been implicated to induce adverse drug reactions such drug-induced liver injury (DILI) and immune-mediated adverse reactions in Human Immunodeficiency Virus (HIV) infected individuals. Patients that develop adverse drug reactions tend to have prolonged stays in hospital and may require to change to alternative regimens if reactions persist upon rechallenge or if rechallenge is contraindicated due to severity of the adverse reaction. Diagnosis of DILI remains a huge obstacle that delays timely interventions, since it is still based largely on exclusion of other causes. There is an urgent need to develop robust diagnostic and predictive biomarkers that could be used alongside the available tools (biopsy, imaging, and serological tests for liver enzymes) to give a specific diagnosis of DILI. Crucial to this is also achieving consensus in the definition of DILI so that robust studies can be undertaken. Importantly, it is crucial that we gain deeper insights into the mechanism of DILI so that patients can receive appropriate management. In general, it has been demonstrated that the mechanism of ART-induced liver injury is driven by four main mechanisms: mitochondrial toxicity, metabolic host-mediated injury, immune reconstitution, and hypersensitivity reactions. The focus of this review is to discuss the type and phenotypes of DILI that are caused by the first line ART regimens. Furthermore, we will summarize recent studies that have elucidated the cellular and molecular mechanisms of DILI both in vivo and in vitro.

Assessing inflammation and its role in comorbidities among persons living with HIV

PURPOSE OF REVIEW

This article describes the use of biomarkers in expanding our understanding of chronic non-AIDS comorbidities among persons living with HIV (PLWH) receiving antiretroviral therapy (ART).

RECENT FINDINGS

We review current evidence that biomarkers of chronic immune activation and inflammation associate with a broad spectrum of end-organ diseases in PLWH. We discuss how ART may impact inflammation associated with HIV infection and the degree to which inflammation persists despite effective suppression of viral replication in plasma. We then discuss the limitations of the current literature, which lacks evidence of causality and disproportionately involves a few protein biomarkers that are unable to disentangle complex and overlapping biological pathways.

SUMMARY

Premature end-organ disease among PLWH has been repeatedly associated with higher levels of blood biomarkers reflecting inflammation and immune activation, which, despite viral suppression and CD4 T-cell increases after ART treatment, remain elevated relative to uninfected persons. There remain important unanswered questions with implications for the development of anti-inflammatory treatment strategies aimed at mitigating excess risk for end-organ comorbidities among PLWH.

Changes in liver stiffness after ART initiation in HIV-infected Nigerian adults with and without chronic HBV

BACKGROUND

There are limited data from sub-Saharan Africa on long-term liver fibrosis changes in HIV- and HIV/HBV-infected individuals.

OBJECTIVES

To assess the effects of ART on liver stiffness measurement (LSM) using transient elastography (TE) in HIV- and HIV/HBV-infected Nigerian adults and examine factors associated with fibrosis regression.

METHODS

We included ART-naive HIV- and HIV/HBV-infected adults (≥18 years) enrolled in a prospective, longitudinal study of liver disease between July 2011 and February 2015 at Jos University Teaching Hospital HIV Care and Treatment Centre in Nigeria. Patients initiated ART and had TE at baseline and follow-up (year 3). LSM cut-offs for Metavir scores were 5.9, 7.6 and 9.4 kPa for moderate fibrosis, advanced fibrosis and cirrhosis, respectively. We used multivariable regression to identify factors associated with TE (≥1 Metavir) stage decline.

RESULTS

A total of 106 HIV- and 71 HIV/HBV-infected patients [70.5% female and median age = 34 years (IQR = 29-42 years)] were studied. Baseline LSM and median LSM decline were significantly higher in HIV/HBV- versus HIV-infected patients; 41% of HIV/HBV-infected patients regressed ≥1 Metavir stage versus 17% of HIV-infected patients (P < 0.01); LSM scores at year 3 were not significantly different between HIV- and HIV/HBV-infected patients. In multivariable analyses, patients with baseline CD4+ T cells ≥200 (versus <200) cells/mm3 and lower BMIs were more likely to experience LSM stage decline.

CONCLUSIONS

HBV coinfection does not attenuate LSM declines in HIV-infected patients after ART initiation despite being a risk factor for more advanced liver disease prior to therapy. The inverse association between BMI and TE stage decline needs further investigation.

A gathering storm: HIV infection and nonalcoholic fatty liver disease in low and middle-income countries

: Despite the decreasing total incidence of liver-related deaths, liver disease remains one of the major non-AIDS causes of morbidity and mortality amongst people living with HIV, and a significant proportion of liver disease in these individuals can be attributed to nonalcoholic fatty liver disease (NAFLD). NAFLD in HIV infection is a growing problem in view of increasing life expectancy associated with the use of effective antiretroviral therapy (ART), wider uptake of ART and increasing rates of obesity in many Asian as well as western countries. The problem may be more pronounced in developing countries where there are limited resources available for mass screening and diagnosis of NAFLD. There is a small but growing body of literature examining NAFLD in the setting of HIV, with data from low and middle-income countries (LMICs) particularly lacking. Here, we review the cohort data on NAFLD in HIV, and discuss the risk factors, pathogenesis of hepatic steatosis, NAFLD and nonalcoholic steatohepatitis (NASH), diagnostic approaches and therapeutic options available for NAFLD in the setting of HIV, and the specific challenges of NAFLD in HIV for LMICs.

Mannose-binding lectin concentrations in people living with HIV/AIDS infected by HHV-8

Background

Mannose-binding lectin (MBL) plays an important role in the innate immune response by activating the complement system via the lectin pathway, and it has been studied in several viral infections; however, the influence of MBL in PLWHA infected with HHV-8 is unknown. The objective of this study was to verify the association of MBL deficient plasma concentrations in HIV/HHV-8 coinfected and HIV monoinfected patients and to correlate these concentrations with HIV viral load and CD4 counts in both groups.

Results

This was an analytical study of case-controls consisting of PLWHA monitored at the medical outpatient of Infectious and Parasitic Diseases of the clinical hospital in the Federal University of Pernambuco. Plasma concentrations of MBL were obtained by an enzyme-linked immunosorbent assay (ELISA) using a commercial Human Mannose Binding Lectin kit (MyBioSource, Inc.) that was performed according to the manufacturer’s guidelines, with values < 100 ng/ml considered deficient. A total of 245 PLWHA samples were analysed; 118 were HIV/HHV-8 coinfected and 127 were HIV monoinfected; 5.1% (6/118) of the coinfected patients and 3.2% (4/127) of the monoinfected patients (p = 0.445) were considered plasma concentration deficient. The median of the plasma concentrations of MBL in the coinfected patients was 2803 log₁₀ ng/ml and was 2.959 log₁₀ ng/ml in the monoinfected patients (p = 0.001). There was an inverse correlation between the plasma concentrations of MBL and the HIV viral load in both groups, but no correlation with the CD4 count.

Conclusions

Although the plasma concentrations considered deficient in MBL were not associated with HHV-8 infection in PLWHA, the coinfected patients showed lower MBL concentrations and an inverse correlation with HIV viral load, suggesting that there may be consumption and reduction of MBL due to opsonization of HIV and HHV-8, leading to the reduction of plasma MBL and non-accumulation in the circulation.

Differential contribution of chronic binge alcohol and antiretroviral therapy to metabolic dysregulation in SIV-infected male macaques

The incidence of alcohol use disorder (AUD) is higher among people living with HIV (PLWH). The advent and continued development of antiretroviral therapy (ART) has significantly reduced mortality, shifting the course of HIV infection to a chronic illness. However, this is associated with an increased incidence of comorbid conditions, including type 2 diabetes mellitus, insulin resistance, and cardiovascular complications. Using a nonhuman primate model of simian immunodeficiency virus (SIV) infection, previous studies have demonstrated that chronic binge alcohol (CBA) administration decreases whole body insulin responsiveness, irrespective of ART administration. The objective of the current study was to determine the effects of CBA and ART on insulin-sensitive peripheral tissues before the development of overt clinical symptoms of SIV disease. Our results show that CBA reduced omental adipocyte cell size, increased collagen expression, and decreased the in vitro differentiation potential of adipose-derived stem cells. In contrast, it did not alter skeletal muscle or omental or hepatic expression of insulin signaling proteins. However, ART significantly decreased skeletal muscle expression of phosphatase and tensin homolog, total mechanistic target of rapamycin, and ribosomal protein S6. In addition, ART increased hepatic phosphorylation of AMP-activated protein kinase α and increased gene expression of key enzymes required for gluconeogenesis and fatty acid synthesis. These findings suggest that CBA and ART differentially promote adverse metabolic effects in an organ-specific manner that may underlie insulin resistance associated with alcohol, SIV, and ART. Whether this is translated in PLWH with AUD remains to be determined.

The Role of Transforming Growth Factor Beta-1 in the Progression of HIV/AIDS and Development of Non-AIDS-Defining Fibrotic Disorders

Even after attainment of sustained viral suppression following implementation of highly active antiretroviral therapy, HIV-infected persons continue to experience persistent, low-grade, systemic inflammation. Among other mechanisms, this appears to result from ongoing microbial translocation from a damaged gastrointestinal tract. This HIV-related chronic inflammatory response is paralleled by counteracting, but only partially effective, biological anti-inflammatory processes. Paradoxically, however, this anti-inflammatory response not only exacerbates immunosuppression but also predisposes for development of non-AIDS-related, non-communicable disorders. With respect to the pathogenesis of both sustained immunosuppression and the increased frequency of non-AIDS-related disorders, the anti-inflammatory/profibrotic cytokine, transforming growth factor-β1 (TGF-β1), which remains persistently elevated in both untreated and virally suppressed HIV-infected persons, may provide a common link. In this context, the current review is focused on two different, albeit related, harmful activities of TGF-β1 in HIV infection. First, on the spectrum of anti-inflammatory/immunosuppressive activities of TGF-β1 and the involvement of this cytokine, derived predominantly from T regulatory cells, in driving disease progression in HIV-infected persons via both non-fibrotic and profibrotic mechanisms. Second, the possible involvement of sustained elevations in circulating and tissue TGF-β1 in the pathogenesis of non-AIDS-defining cardiovascular, hepatic, pulmonary and renal disorders, together with a brief comment on potential TGF-β1-targeted therapeutic strategies.