Impact of nevirapine on lipid metabolism

Associations Between Central Obesity and Lifelong Antiviral Therapy in Adults Living With HIV Acquired From Early Childhood

BACKGROUND

Little is known regarding the long-term effects of antiretroviral (ARV) exposure on body composition for people living with HIV (PLWH) since early childhood. This study explores changes in body fat distribution in relation to ARV exposure.

METHODS

We conducted a prospective study of adults with perinatal HIV (n = 70) using dual-energy X-ray absorptiometry and standard anthropometrics. Trunk to limb fat ratio and waist to hip ratio were compared cross-sectionally to 47 matched controls. Furthermore, changes in body composition and ARV exposure were evaluated longitudinally in a subset of 40 PLWH with a median follow-up of 7 years.

RESULTS

Cross-sectional comparisons of PLWH with controls revealed significantly higher waist to hip ratio, trunk to limb fat ratio, HOMA-IR, and triglycerides, whereas BMI did not differ. Among PLWH with longitudinal follow-up, the prevalence of overweight increased from 27.5% to 52.5% and obesity from 12.5% to 25%; waist to hip and trunk to limb fat ratios also increased (P < 0.0001). Changes in waist to hip ratio were positively correlated with longer exposure during follow-up to darunavir (r = 0.36; P = 0.02), whereas increases in trunk to limb fat ratio were positively correlated with longer exposure to stavudine (r = 0.39; P = 0.01) and didanosine (r = 0.39; P = 0.01) but inversely associated with emtricitabine (r = -0.33; P = 0.04). Increases in waist to hip ratio were correlated with increases in triglyceride levels (r = 0.35; P = 0.03).

CONCLUSION

This study presents strong evidence for persistent and worsening central adiposity in young adults with lifelong HIV and extensive ARV exposure. As this cohort ages, continued evaluation of the body composition and metabolic impact of lifelong ARV therapy is warranted to optimize long-term health.

The potential role of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) single-tablet regimen in the expanding spectrum of fixed-dose combination therapy for HIV

Single-tablet regimens (STRs) of highly safe and effective combination antiretroviral therapy (cART) have had a significant beneficial impact on the clinical outcomes and lives of people living with HIV (PLHIV). As a consequence, healthcare professionals caring for PLHIV in high-income countries have increasingly focused on issues beyond those related to HIV itself, i.e. HIV-related neurological disease, or associated opportunistic infections, which include co-infections, and primarily age- and lifestyle-related comorbidities such as cardiovascular disease, diabetes mellitus, renal impairment, osteoporosis and frailty. This review considers drug side effects and comorbidities seen in PLHIV and evaluates the role of a recently licensed STR - bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) - in mitigating some of those challenges. Factors that need to be evaluated for initial cART regimens include: pretreatment CD4 cell count; plasma HIV RNA; HIV drug resistance; hepatitis B co-infection; HLA-B*5701 status; drug-drug interactions; pregnancy and pregnancy potential; psychiatric and physical comorbidities such as renal or bone disease, as well as simplicity and adherence-friendliness, all of which need to be considered in all lines of therapy. BIC/FTC/TAF constitutes a new STR that includes an unboosted integrase strand transfer inhibitor with a high barrier against resistance with TAF and FTC. Its virological efficacy was non-inferior to dolutegravir-based regimens previously recommended by most guidelines for treatment initiation in large double-blind, randomised clinical trials in treatment-naïve or switch patients over 96 weeks. Tolerability and pharmacological properties of the regimen make it a useful tool to address several of the clinical management issues raised above.

Impact of antiretroviral therapy on lipid metabolism of human immunodeficiency virus-infected patients: Old and new drugs

For human immunodeficiency virus (HIV)-infected patients, the 1990s were marked by the introduction of highly active antiretroviral therapy (HAART) representing a new perspective of life for these patients. The use of HAART was shown to effectively suppress the replication of HIV-1 and dramatically reduce mortality and morbidity, which led to a better and longer quality of life for HIV-1-infected patients. Apart from the substantial benefits that result from the use of various HAART regimens, laboratory and clinical experience has shown that HAART can induce severe and considerable adverse effects related to metabolic complications of lipid metabolism, characterized by signs of lipodystrophy, insulin resistance, central adiposity, dyslipidemia, increased risk of cardiovascular disease and even an increased risk of atherosclerosis. New drugs are being studied, new therapeutic strategies are being implemented, and the use of statins, fibrates, and inhibitors of intestinal cholesterol absorption have been effective alternatives. Changes in diet and lifestyle have also shown satisfactory results.

Nevirapine in the treatment of HIV

Nevirapine (Viramune, Boehringer Ingelheim Ltd) is the first marketed non-nucleoside reverse transcriptase inhibitor. As with any antiretroviral drug, nevirapine should always be used as part of a fully suppressive regimen. Clinical studies have shown that nevirapine-containing regimens may accomplish durable virological and immunological responses in approximately half of all antiretroviral-naive patients. It can also be successfully used as a component of salvage therapies and as a part of a strategy to simplify protease inhibitor-containing regimens. Nevirapine has a beneficial effect on the lipid profile in both treatment-naive and -experienced patients. Nevirapine also has an important role in preventing mother-to-child transmission of HIV. It is usually well-tolerated with rash and liver toxicity being the most frequently reported adverse events. Nevirapine interacts with cytochrome P450 enzymes both as a substrate and as an inducer. For this reason, therapeutic drug monitoring should be recommended whenever nevirapine is used with protease inhibitors, methadone (Methadose, Rosemont Pharmaceuticals Ltd), oral contraceptives, rifampicin (Rifadin, Aventis Pharma) and other potentially interacting drugs. Nevirapine-resistant mutations are common to the non-nucleoside reverse transcriptase inhibitor family and they include K103N, V106A, Y181C, Y188C and G190A. A better understanding of the nevirapine profile will certainly contribute to ensuring that its clinical application becomes more effective and beneficial.

Association of clinical and therapeutic factors with incident dyslipidemia in a cohort of human immunodeficiency virus-infected and non-infected adults: 1994-2011

OBJECTIVE

The aim of this study was to determine the incidence rate of dyslipidemia in a retrospective cohort of human immunodeficiency virus (HIV)-infected and non-HIV-infected adults and to evaluate the association of incident dyslipidemia with exposure to combination antiretroviral therapy (cART).

METHODS

The study cohort included HIV-infected individuals and a matched group of non-HIV-infected individuals served through the South Carolina Medicaid database in 1994-2011. Linkage with the HIV/AIDS surveillance database provided time-varying viro-immunological status. Time-dependent proportional hazards analysis and marginal structural models were used to assess the demographic, therapeutic, and clinical factors associated with incident dyslipidemia.

RESULTS

Among 13,632 adults with a median age of 39 years, the overall incidence rate per 1000 person years of dyslipidemia was higher in cART-treated compared to cART-naïve and matched non-HIV groups (24.55 vs. 14.32 vs. 23.23, respectively). Multivariable results suggested a significantly higher risk of dyslipidemia in the cART-treated HIV-infected group [adjusted hazard ratio (aHR)=1.18; 95% confidence interval (CI)=1.07-1.30] and a significantly lower risk in the cART naïve HIV-infected group (aHR=0.66; CI=0.53-0.82) compared to the control non-HIV-infected group. Marginal structural modeling suggested a significant association between incident dyslipidemia and exposure to both protease inhibitor- [adjusted rate ratio (aRR)=1.27; CI=1.08-1.49] and non-nucleoside reverse transcriptase inhibitor- (aRR=1.78; CI=1.19-2.66) based cART regimens. Pre-existing hypertension, obesity, and diabetes increased the risk of dyslipidemia, whereas hepatitis C virus, lower CD4(+) T cell count, and higher HIV viral load had a protective effect.

CONCLUSIONS

Incident dyslipidemia is lower in the early stages of HIV infection, but may significantly increase with cumulative exposure to cART. Viro-immunological status and underlying comorbidities have a strong association with the onset of dyslipidemia.

Pro-atherogenic lipid changes and decreased hepatic LDL receptor expression by tocilizumab in rheumatoid arthritis

OBJECTIVES

Blocking the interleukin-6 pathway by tocilizumab (TCZ) has been associated with changes in the lipoprotein profile, which could adversely impact cardiovascular (CV) risk in patients with rheumatoid arthritis (RA). In the present study, we addressed the effect of TCZ on lipoproteins in both fasting and non-fasting state in RA patients and tested the effect of TCZ on LDL receptor (LDLr) expression in vitro.

METHODS

Twenty patients with active RA and an inadequate response to TNF blockers received monthly TCZ intravenously. On week 0, 1 and 6 blood was drawn before and after an oral fat load, the lipid profiles and HDL antioxidative capacity were measured. Effects of TCZ on LDLr expression in transfected HepG2 cells were subjected.

RESULTS

After 6 weeks of TCZ, total cholesterol increased by 22% (4.8 ± 0.9 to 5.9 ± 1.3 mmol/L; p < 0.001), LDLc by 22% (3.0 ± 0.6 to 3.6 ± 0.8 mmol/L; p < 0.001) and HDLc by 17% (1.4 ± 0.4 to 1.7 ± 0.7 mmol/L; p < 0.016). Fasting triglycerides (TG) increased by 48% (1.0 ± 0.4 to 1.4 ± 0.8 mmol/L; p = 0.011), whereas postprandial incremental area under the curve TG increased by 62% (p = 0.002). Lipid changes were unrelated to the change in disease activity or inflammatory markers. No difference in HDL antioxidative capacity was found. In vitro, LDLr expression in cultured liver cells was significantly decreased following TCZ incubation (P < 0.001).

CONCLUSIONS

TCZ adversely impacts on both LDLc as well as fasting and postprandial TG in patients with RA. The changes in hepatic LDLr expression following TCZ imply that adverse lipid changes may be a direct hepatic effect of TCZ. The net effect of TCZ on CV-morbidity has to be confirmed in future clinical trials.

2'-Deoxythymidine adducts from the anti-HIV drug nevirapine

Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used against HIV-1. Currently, NVP is the most widely used anti-HIV drug in developing countries, both in combination therapy and to prevent mother-to-child transmission of HIV. Despite its efficacy against HIV, NVP produces a variety of toxic responses, including hepatotoxicity and skin rash. It is also associated with increased incidences of hepatoneoplasias in rodents. In addition, epidemiological data suggest that NNRTI use is a risk factor for non-AIDS-defining cancers in HIV-positive patients. Current evidence supports the involvement of metabolic activation to reactive electrophiles in NVP toxicity. NVP metabolism includes oxidation to 12-hydroxy-NVP; subsequent Phase II sulfonation produces an electrophilic metabolite, 12-sulfoxy-NVP, capable of reacting with DNA to yield covalent adducts. Since 2'-deoxythymidine (dT) adducts from several alkylating agents are regarded as having significant mutagenic/carcinogenic potential, we investigated the formation of NVP-dT adducts under biomimetic conditions. Toward this goal, we initially prepared and characterized synthetic NVP-dT adduct standards using a palladium-mediated Buchwald-Hartwig coupling strategy. The synthetic standards enabled the identification, by LC-ESI-MS, of 12-(2'-deoxythymidin-N3-yl)-nevirapine (N3-NVP-dT) in the enzymatic hydrolysate of salmon testis DNA reacted with 12-mesyloxy-NVP, a synthetic surrogate for 12-sulfoxy-NVP. N3-NVP-dT, a potentially cytotoxic and mutagenic DNA lesion, was also the only dT-specific adduct detected upon reaction of dT with 12-mesyloxy-NVP. Our data suggest that N3-NVP-dT may be formed in vivo and play a role in the hepatotoxicity and/or putative hepatocarcinogenicity of NVP.

First-line antiretroviral therapy and changes in lipid levels over 3 years among HIV-infected adults in Tanzania

BACKGROUND

With the rapid rollout of antiretroviral therapy (ART) in sub-Saharan Africa (SSA), there has been an increasing concern about cardiovascular risks related to ART. However, data from human immunodeficiency virus (HIV)-infected populations from this region are very limited.

METHODS

Among 6385 HIV-infected adults in Dar es Salaam, Tanzania, we investigated the nonfasting lipid changes over 3 years following ART initiation and their associations with different first-line ART agents that are commonly used in SSA.

RESULTS

In the first 6 months of ART, the prevalence of dyslipidemia decreased from 69% to 54%, with triglyceride (TG) decreasing from 127 mg/dL to 113 mg/dL and high-density lipoprotein (HDL) cholesterol increasing from 39 mg/dL to 52 mg/dL. After 6 months, TG returned to its baseline level and increased to 139 mg/dL at 3 years; total cholesterol and low-density lipoprotein cholesterol continued to increase whereas HDL cholesterol leveled off. The prevalence of dyslipidemia increased to 73% after a 3-year follow-up. In multivariate analyses, patients on zidovudine-containing regimens had a greater reduction in TG levels at 6 months (-16.0 vs -6.3 mg/dL), and a lower increase at 3 years compared to patients on stavudine-containing regimens (2.1 vs 11.7 mg/dL, P < .001); patients on nevirapine-based regimens had a higher increase in HDL cholesterol levels at 3 years compared to those on efavirenz-based regimens (13.6 vs 9.5 mg/dL, P = .01).

CONCLUSIONS

Our findings support the latest World Health Organization guidelines on the substitution of stavudine in first-line ART in resource-limited settings, and provide further evidence for selection of lipid-friendly ART for patients in SSA.

Lipid profiles in young HIV-infected children initiating and changing antiretroviral therapy

BACKGROUND

Both HIV infection and antiretroviral therapy are associated with dyslipidemias in adults, but there are fewer data on outcomes in young children. Here we examined lipid profile changes in a cohort of young children before and after suppression on an initial ritonavir-boosted lopinavir (LPV/r)-based regimen and after switch to a nevirapine (NVP)-based regimen.

METHODS

One hundred ninety-five HIV-infected children who initiated LPV/r-based therapy when <24 months of age at 1 site in Johannesburg, South Africa, and who achieved viral suppression (<400 copies/mL sustained for ≥ 3 months) were randomized to either continue on the LPV/r-based regimen (n = 99) or to switch to a NVP-based regimen (n = 96). Nonfasting concentrations of total cholesterol (TC), low-density lipoprotein, high-density lipoprotein (HDL), and triglycerides (TG) were measured pretreatment, at randomization when suppressed, and at 9, 20, and 31 months postrandomization.

RESULTS

Median age at treatment initiation was 9 months, and the initial regimen was maintained for an average of 9 months before randomization. TC, low-density lipoprotein, and HDL increased from pretreatment to randomization (P < 0.0001) and TC/HDL ratio and TG decreased (P < 0.0001). After switching to NVP, HDL was significantly higher (P < 0.02) and TC/HDL and TG significantly lower (P < 0.0001) through 31 months postswitch relative to remaining on the LPV/r-based regimen.

CONCLUSION

Initiating antiretroviral therapy was associated with changes to a more favorable lipid profile in young children. Switching from a LPV/r-based regimen to a NVP-based regimen accentuated and continued these improvements. Investigation of safe and effective methods for managing dyslipidemias in children of different ages in resource-limited settings is warranted.

Evaluation of the safety and effectiveness of nevirapine plus coformulated tenofovir/emtricitabine as first-line therapy in routine clinical practice

Despite having demonstrated noninferior efficacy against atazanavir/ritonavir plus coformulated tenofovir/emtricitabine (cTDF/FTC), the combination of nevirapine plus cTDF/FTC is not included among preferred regimens in some international guidelines. This combination is frequently used in Spain. We analyzed its effectiveness and safety as first-line therapy in a routine clinical practice. A retrospective, multicenter study was performed in treatment-naive HIV-1-infected subjects who started nevirapine plus cTDF/FTC as first-line therapy according to the nevirapine CD4(+) cell count threshold. The primary endpoint was the proportion of subjects with plasma HIV-1 RNA <50 copies/ml at week 48. We included 123 subjects starting the regimen from 2005 to 2008. The median age was 41.0 years, the median baseline CD4(+) cell count was 215 cells/μl, the median plasma viral load (VL) was 4.83 log(10) copies/ml, and 22% had hepatitis C coinfection. At week 48, 96 subjects (78%; 95% CI: 69.9-84.4) had a VL <50 copies/ml in an ITT analysis, and the median rise in the CD4(+) cell count was 118 cells/μl. Virological failure was observed in 6.5% (8/123) of subjects, all them before week 24 and related to poor adherence. There was no relationship between virological failure and baseline CD4(+) cell count or VL. Ten percent (13/123) of the subjects discontinued the treatment due to adverse events. There was a significant decrease in total/HDL-cholesterol ratio (p=0.03) with an increase in HDL-cholesterol (p=0.01) over 48 weeks. The combination of nevirapine plus cTDF/FTC showed a high virological efficacy without unexpected toxicities as a first-line treatment in a routine clinical practice.

Morphological and metabolic components of lipodystrophy in various nevirapine-based highly active antiretroviral therapy (HAART) regimens: a cross-sectional, observational study

BACKGROUND

Morphological abnormalities (lipoatrophy and central fat accumulation) and metabolic changes (dyslipidaemia and glucose regulation impairment) have emerged as components of lipodystrophy and as major tolerability issues with long-term use of highly active antiretroviral therapy (HAART) in HIV-positive patients. Protease inhibitors (PIs) are recognized as having the greatest impact in terms of metabolic complications, followed by nucleoside reverse transcriptase inhibitors, while the non-nucleoside reverse transcriptase inhibitors (NNRTIs) have the least impact. In particular, regimens based on the NNRTI nevirapine have been shown to achieve significant metabolic benefits and may help to improve dyslipidaemia. Improvements in body shape changes associated with lipodystrophy have also been reported when nevirapine replaced a PI in long-term triple therapy.

OBJECTIVE

The objective of this cross-sectional observational ('real-world') study was to investigate the effect of three HAART regimens plus stable nevirapine therapy on morphological and metabolic components of lipodystrophy in HIV-infected patients.

METHODS

Consecutive patients (aged >18 years) with serologically documented HIV infection, who had received HAART for at least 2 years and who had been diagnosed with lipodystrophy, were followed up as outpatients at the metabolic clinic of the University of Modena and Reggio Emilia, Modena, Italy. Patients received stable nevirapine therapy plus fixed-dose combinations of tenofovir disoproxil fumarate plus emtricitabine (Truvada(®); TVD), zidovudine plus lamivudine (3TC) [Combivir(®); CBV], or abacavir plus lamivudine (Kivexa(®); KVX). Multivariate regression analyses were performed to analyse predictors of four components of lipodystrophy: lipoatrophy using leg fat mass measured by dual-emission x-ray absorptiometry (DXA), fat accumulation using waist circumference, dyslipidaemia using apolipoprotein (Apo)B/ApoA1 ratio, and glucose intolerance using the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR).

RESULTS

Overall, 101 patients were enrolled (TVD group = 61, CBV group = 20, KVX group = 20); 191 observations were analysed. Male sex was associated with reduced leg fat mass, while age and body mass index (BMI) were associated with increased leg fat mass (all p < 0.05). Leg fat mass and male sex were associated with increased waist circumference (p < 0.001 for both). Leg fat mass predicted reduced ApoB/ApoA1 ratio, while age and BMI predicted increased ApoB/ApoA1 ratio (all p < 0.05). BMI predicted HOMA-IR increase (p = 0.0017). No differences in lipoatrophy, central fat accumulation, dyslipidaemia or glucose metabolism were observed among any of the three different nevirapine plus nucleoside backbone groups (TVD, CBV or KVX).

CONCLUSION

HAART including nevirapine has a limited impact on components of lipodystrophy in patients with HIV infection. Further studies are needed to verify if nevirapine overcomes the expected distinct lipodystrophy risk profile associated with different nucleoside backbone therapies.

Morphological and metabolic components of lipodystrophy in various nevirapine-based highly active antiretroviral therapy (HAART) regimens: a cross-sectional, observational study

BACKGROUND

Morphological abnormalities (lipoatrophy and central fat accumulation) and metabolic changes (dyslipidaemia and glucose regulation impairment) have emerged as components of lipodystrophy and as major tolerability issues with long-term use of highly active antiretroviral therapy (HAART) in HIV-positive patients. Protease inhibitors (PIs) are recognized as having the greatest impact in terms of metabolic complications, followed by nucleoside reverse transcriptase inhibitors, while the non-nucleoside reverse transcriptase inhibitors (NNRTIs) have the least impact. In particular, regimens based on the NNRTI nevirapine have been shown to achieve significant metabolic benefits and may help to improve dyslipidaemia. Improvements in body shape changes associated with lipodystrophy have also been reported when nevirapine replaced a PI in long-term triple therapy.

OBJECTIVE

The objective of this cross-sectional observational ('real-world') study was to investigate the effect of three HAART regimens plus stable nevirapine therapy on morphological and metabolic components of lipodystrophy in HIV-infected patients.

METHODS

Consecutive patients (aged >18 years) with serologically documented HIV infection, who had received HAART for at least 2 years and who had been diagnosed with lipodystrophy, were followed up as outpatients at the metabolic clinic of the University of Modena and Reggio Emilia, Modena, Italy. Patients received stable nevirapine therapy plus fixed-dose combinations of tenofovir disoproxil fumarate plus emtricitabine (Truvada(®); TVD), zidovudine plus lamivudine (3TC) [Combivir(®); CBV], or abacavir plus lamivudine (Kivexa(®); KVX). Multivariate regression analyses were performed to analyse predictors of four components of lipodystrophy: lipoatrophy using leg fat mass measured by dual-emission x-ray absorptiometry (DXA), fat accumulation using waist circumference, dyslipidaemia using apolipoprotein (Apo)B/ApoA1 ratio, and glucose intolerance using the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR).

RESULTS

Overall, 101 patients were enrolled (TVD group = 61, CBV group = 20, KVX group = 20); 191 observations were analysed. Male sex was associated with reduced leg fat mass, while age and body mass index (BMI) were associated with increased leg fat mass (all p < 0.05). Leg fat mass and male sex were associated with increased waist circumference (p < 0.001 for both). Leg fat mass predicted reduced ApoB/ApoA1 ratio, while age and BMI predicted increased ApoB/ApoA1 ratio (all p < 0.05). BMI predicted HOMA-IR increase (p = 0.0017). No differences in lipoatrophy, central fat accumulation, dyslipidaemia or glucose metabolism were observed among any of the three different nevirapine plus nucleoside backbone groups (TVD, CBV or KVX).

CONCLUSION

HAART including nevirapine has a limited impact on components of lipodystrophy in patients with HIV infection. Further studies are needed to verify if nevirapine overcomes the expected distinct lipodystrophy risk profile associated with different nucleoside backbone therapies.

Nevirapine once daily: pharmacology, metabolic profile and efficacy data of the new extended-release formulation

INTRODUCTION

Nevirapine (NVP), a non-nucleoside reverse transcriptase inhibitor, has been an important component of HIV infection treatment for many years. Currently, twice-a-day dosing is required for the successful application of NVP immediate release (IR), but there is potential for a more convenient once-a-day antiretroviral combination.

AREAS COVERED

The purpose of this article is to review the recent data on once-daily NVP extended release (XR) looking at all the important pharmacologic, pharmacokinetic and clinical data on NVP IR/XR through a systematic MEDLINE database search as well as a review of abstracts presented at international HIV meetings on NVP XR studies up to December 2010. The article provides the reader with an overview of all the pharmacodynamic and pharmacokinetic aspects of NVP IR/XR, as well as its preclinical and clinical efficacy and its safety.

EXPERT OPINION

NVP XR is as effective as NVP IR among HIV-infected patients with a similar safety profile. NVP XR requires careful monitoring during initiation, but its favorable lipid profile may be of clinical benefit in reducing the risk for coronary artery disease in HIV-infected patients who are receiving long-term antiretroviral therapy. Further research is needed to predict short-term toxicity.

Premature onset of cardiovascular disease in HIV-infected individuals: the drugs and the virus

Life expectancy in HIV-infected individuals has been greatly enhanced through immunologic restoration and virologic suppression resulting from antiretroviral therapy. Current clinical HIV care in Western countries focuses on treatment of drug toxicities and prevention of comorbidities. These non-AIDS HIV-related comorbidities, such as cardiovascular disease, occur even in individuals with virologic suppression and manifest at an earlier age than when normally presenting in the general population. While traditional risk factors are present in many HIV-infected individuals who develop cardiovascular disease, the additional roles of HIV-related chronic inflammation and immune activation as well as chronic HIV viremia may be significant. This review provides current evidence for the contributions of the virus, in terms of both chronic viremia and its contribution via chronic low-level inflammation, immune activation, premature immune senescence and dyslipidemia, to the pathogenesis of HIV-related cardiovascular disease, and balances this against the propensity of specific antiretroviral therapies to cause cardiovascular disease, in particular through altered cholesterol metabolism.

Antiretroviral therapy as a cardiovascular disease risk factor: fact or fiction? A review of clinical and surrogate outcome studies

PURPOSE OF REVIEW

The aim of this paper is to assess the contribution of antiretroviral therapy to cardiovascular disease, by evaluating relevant clinical and surrogate outcome studies.

RECENT FINDINGS

A large proportion of patients receiving antiretroviral therapy develop insulin resistance and dyslipidemia, particularly if exposed to protease inhibitors. Recent findings from clinical outcome studies suggest that protease inhibitor-based therapy is associated with an increased risk of cardiovascular disease, with a consistent estimated increased risk of 1.16 to 1.17 for each additional year of protease inhibitor exposure. Antiretroviral therapy discontinuation, however, has also been linked with increased risk of cardiovascular disease. There are some data from clinical and surrogate outcome studies, that interventions addressing conventional risk factors and switching antiretroviral therapy may reduce cardiovascular disease risk.

SUMMARY

Combination antiretroviral therapy in general, and protease inhibitor-based antiretroviral therapy in particular, is associated with an increased risk of cardiovascular disease. This risk is likely mediated, in part, by changes in blood lipids. The absolute risk of cardiovascular disease for the individual patient depends on his or hers composite risk profile. It is becoming increasingly important to carry out an adequate cardiovascular disease risk assessment in each patient, in order to identify patients in need of specific interventions.

Clinical factors associated with plasma F2-isoprostane levels in HIV-infected adults

PURPOSE

Oxidant stress may be an effect of antiretroviral therapy (ART) or chronic HIV infection. Plasma F2-isoprostanes (F2-IsoP) reflect lipid peroxidation and oxidant stress and have been described in ART-associated toxicities. We explored factors associated with F2-IsoP in HIV-infected adults.

METHODS

HIV-infected adults enrolled in this cross-sectional study were (a) on ART including zidovudine or stavudine but not non-nucleoside reverse transcriptase inhibitors (NNRTI), (b) on ART including NNRTI, or (c) not on ART. Plasma F2-IsoP levels were quantified by GC/MS, and clinical and laboratory data were collected at enrollment.

RESULTS

Among 285 participants, 24% were female, 37% were African American, and 194 (68%) were on ART; 44 (23%) of whom were receiving efavirenz, 45 (23%) nevirapine, and 85 (44%) protease inhibitors. Median F2-IsoP was lower in those on NNRTI than those on ART without NNRTI (p = .02). In a multivariable model, factors independently associated with increased F2-IsoP were female sex (p = .002), higher BMI (p = .01), and heavy smoking (p = .004). There was a trend toward lower F2-IsoP among nevirapine users (p = .054).

CONCLUSIONS

Among HIV-infected adults, oxidant stress status differs by sex, BMI, smoking status, and perhaps specific ART. Prospective studies should better define relationships between oxidant stress and complications of HIV infection and its therapy.

Immunomodulation by statins: mechanisms and potential impact on autoimmune diseases

Statins are inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and they are the most effective agents for lowering cholesterol in clinical practice for the treatment of cardiovascular diseases. However, it has become clear that statins also have pleiotropic immunomodulatory effects in addition to their lipid-lowering properties. As a result, much attention has been focused on their potential as therapeutic agents for the treatment of inflammatory autoimmune diseases. In this review the effect of statins on the expression and function of a variety of immune-relevant molecules will be discussed alongside the underlying mechanisms that contribute to the immunomodulatory effects of statins.

Effects of nevirapine and efavirenz on HDL cholesterol levels and reverse cholesterol transport in mice

OBJECTIVE

The mechanism by which non-nucleoside reverse transcriptase inhibitors (NNRTIs) increase HDL cholesterol (HDL-C) in HIV+ patients and the benefits of this with respect to cardiovascular risk are not known. Studies were conducted to test the hypothesis that NNRTIs have a beneficial effect on HDL-C and reverse cholesterol transport (RCT).

METHODS

LDLr-/- and hA-I transgenic mice were fed a Western diet containing either nevirapine (20mg/kg per day), efavirenz (10mg/kg per day), or diet alone. hA-I transgenic mice underwent a study to measure RCT (measured by excretion of macrophage [(3)H]-cholesterol into HDL and feces) at 8 weeks.

RESULTS

LDLr-/- and hA-I transgenic mice treated with nevirapine and efavirenz had a significant increase in HDL-C level (up to 23% in hA-I transgenic) at 4 weeks. However, there was no difference in HDL levels beyond 4 weeks of treatment. At 4 weeks, the FPLC profile of hA-I transgenic mice showed an increase in large HDL. hApoA-I transgenic mice treated with efavirenz for 4 weeks had increased expression of human apoA-I in liver and an increased human apoA-I production rate. Incubation of plasma from hA-I transgenic mice treated for 4 weeks with [(3)H]-cholesterol-labeled macrophages revealed increased cholesterol efflux to plasma from mice treated with efavirenz and nevirapine. Following injection of hA-I transgenic mice treated for 8 weeks with [(3)H]-cholesterol-labeled macrophages, RCT was increased in the efavirenz (p=0.01) group and trended towards an increase in the nevirapine (p=0.15) group.

CONCLUSION

Nevirapine and efavirenz transiently increased HDL-C in LDLr-/- and hA-I transgenic mice fed a Western diet that was associated with increased apoA-I production. An increase in RCT in hA-I transgenic mice at 8 weeks despite no difference in HDL levels indicates that these drugs affect additional factors in the RCT pathway that enhance cholesterol efflux from the macrophage and peripheral tissues to plasma and delivery to liver for excretion. These results suggest that treatment with NNRTIs has a beneficial effect on cholesterol efflux and RCT.

Long-term follow-up of nevirapine-treated patients in a single-centre cohort

OBJECTIVES

We reviewed the safety and efficacy of nevirapine (NVP)-based therapy in all patients initiating NVP-containing combined antiretroviral therapy [cART (>or=3 drugs)] in our clinic since 1994.

METHODS

Patient characteristics and laboratory values from the start of the NVP-based cART regimen to the last available follow-up or to NVP discontinuation were retrieved from an observational database.

RESULTS

Five hundred and seventy-three patients were treated with NVP-based cART for a median of 18.4 (range 0.1-128.8) months. The 1-year cumulative estimated probability of discontinuing NVP-containing regimens for toxicity was 0.203. Only 1.9% developed a grade 3 alanine aminotransferase (ALT) elevation. Significant increases in high-density lipoprotein cholesterol were observed up to month 12 except in treatment-naïve patients, where the increase was limited to 3 months. Discontinuation because of cutaneous reaction was predicted independently by female gender [Hazard Ratio (HR) 3.21, P<0.001] and Centers for Disease Control class C (HR 0.50, P=0.012). Discontinuation because of liver toxicity was predicted independently by anti-hepatitis C virus positivity (HR 3.84, P<0.001). In patients starting NVP-containing cART with undetectable viral loads, the 5-year estimated probability of viral load >400 HIV-1 RNA copies/mL was 0.34.

CONCLUSIONS

Long-term follow-up with an NVP-containing cART showed a low rate of discontinuation caused by liver toxicity and the maintenance of virological suppression in patients switched with undetectable viral loads.

Outcome of protease inhibitor substitution with nevirapine in HIV-1 infected children

BACKGROUND

Protease inhibitors (PIs) have been associated with metabolic complications. There is a trend to switch to simpler therapy to improve these disturbances. We report a case-series describing the effects in metabolic abnormalities in seven HIV-infected children, previously treated with protease inhibitor (PI) after switching to nevirapine.

METHODS

Seven children with stable PI-containing regimen and a long lasting HIV-1 RNA < 50 copies/ml were switched to nevirapine. All patients were naïve to non nucleoside reverse transcriptase inhibitor. PIs were switched to nevirapine. Preentry nucleoside reverse transcriptase inhibitors were maintained. The substitution of PIs with nevirapine was made when the patient showed hyperlipidemia or lipodystrophy or the physician and/or the patient's willingness to simplify. Clinical, laboratory data and anthropometric parameters were assessed every 3 months. Dual-energy X-Ray absorptiometry scans (DXA) was performed at baseline and at 12 months.

RESULTS

Seven HIV-infected children were enrolled. Median age: 130 months (99,177). Median baseline CD4%: 32%. All had HIV-1 RNA < 50 copies/ml. Median length of preentry PI-therapy was 47 months (28, 91). Median age at the beginning of nevirapine was 120 months (99,177). Median decrease in cholesterol in 7.2 mmol/L was observed (P = 0.09), from baseline to 12 months. HDL-cholesterol increased in 5.1 mmol/L (P = 0.03) throughout the study period. No significant changes were observed in DXA with regard to body fat, but changes in total body bone mineral content and lean body content were significant. CD4% remained stable. All patients but one maintained viral load < 50 copies/ml at 12 months. The patient with virologic failure referred bad adherence. Children referred to take medication more easily.

CONCLUSION

PI substitution with nevirapine improved lipid profile in our patients, although this strategy did not show significant changes in body fat or lipodystrophy.

Cardiovascular risk and choice of HIV drug regimen

Since the introduction of combination antiretroviral therapy (cART), there have been many conflicting reports linking its use to the development of cardiovascular disease (CVD). Most antiretroviral drugs have been associated with the development of lipid abnormalities to some degree. However, whereas several large observational studies have reported a link between the use of cART (particularly protease inhibitors) and CVD, evidence linking specific antiretroviral drugs to CVD is limited. Much of the evidence linking cART to the development of dyslipidemia derives from randomized trials. However, given the relative infrequency of CVD in most HIV-positive populations, these may be inadequately powered to demonstrate a link with clinical events. In contrast, large observational studies have greater power to describe the development of clinical events but may be affected by bias. This review will describe the current literature linking cART to CVD as well as the limitations of some of the published studies.

Microalbuminuria in HIV infection

OBJECTIVE

Microalbuminuria is associated with increased risk of cardiovascular disease and mortality. The objective of the study was to evaluate if HIV infection was an independent risk factor for microalbuminuria.

DESIGN

Cross sectional.

METHODS

The relationship between HIV infection and microalbuminuria was assessed using subjects enrolled in the study of Fat Redistribution and Metabolic Change in HIV Infection, which consists of HIV-positive and control men and women. Participants with proteinuria (dipstick >or= 1+) were excluded.

RESULTS

Microalbuminuria (urinary albumin/creatinine ratio, ACR > 30 mg/g) was present in 11% of HIV infected, and 2% of control participants (P < 0.001); a fivefold odds after multivariate adjustment (odds ratio, 5.11; 95% confidence interval, 1.97-13.31; P=0.0008). Several cardiovascular risk factors were associated with higher ACR in HIV participants: insulin resistance (HOMA > 4; 32%, P < 0.0001), systolic blood pressure (21%, P = 0.01 for 120-140 versus < 120 mmHg, and 43%, P = 0.06 for > 140 versus < 120 mmHg), and family history of hypertension (17%, P = 0.03). Higher CD4 cell count was associated with lower albumin/creatinine ratio (-24%, P = 0.009 for 200-400 versus < 200 cells/ml and -26%, P = 0.005 for > 400 versus < 200 cells/ml).

CONCLUSION

HIV infection had a strong and independent association with microalbuminuria, the severity of which was predicted by markers of insulin resistance, hypertension, and advanced HIV infection. These associations warrant further investigation, as the increased prevalence of microalbuminuria in HIV infection may be a harbinger of future risk of cardiovascular and kidney diseases.

Long-Term Body Composition and Metabolic Changes in Antiretroviral Naive Persons Randomized to Protease Inhibitor-, Nonnucleoside Reverse Transcriptase Inhibitor-, or Protease Inhibitor Plus Nonnucleoside Reverse Transcriptase Inhibitor-Based Strategy

OBJECTIVE

To assess changes in metabolic parameters and body composition among 422 antiretroviral-naive patients randomized to 3 antiretroviral therapy (ART) strategies: protease inhibitor (PI; n = 141)-, nonnucleoside reverse transcriptase inhibitor (NNRTI; n = 141)-, or PI + NNRTI (n = 140)-based strategies with a median follow-up of 5 years.

METHODS

At baseline and 1-month (metabolic parameters only) and 4-month follow-up intervals, fat-free mass (FFM) and total body fat were calculated, anthropometric measurements were performed, and fasting metabolic parameters were obtained. Rates of change and mean change were compared.

RESULTS

The PI + NNRTI strategy resulted in greater increases in triglycerides and low-density lipoprotein cholesterol compared with the PI and the NNRTI strategies (P < 0.005), with no differences between the PI and NNRTI strategies. High-density lipoprotein cholesterol increased significantly more in the NNRTI strategy than in the PI strategy (P < 0.005). Insulin and insulin resistance increased similarly with all 3 strategies. Changes in total and regional body composition (loss of subcutaneous tissue area and gains in FFM, nonsubcutaneous tissue area, and visceral tissue area) were observed but did not differ by strategy.

CONCLUSIONS

Long-term follow-up of participants initiating 3 ART strategies demonstrated similar changes in total and regional fat, with no differences by ART strategy. The differential effects on lipid metabolism by strategy and the overall increases in insulin and insulin resistance with all 3 strategies necessitate close monitoring of patients on ART.

Statin-induced proinflammatory response in mitogen-activated peripheral blood mononuclear cells through the activation of caspase-1 and IL-18 secretion in monocytes

Statins, which inhibit 3-hydroxy-3-methylglutaryl CoA reductase, have been shown recently to promote proinflammatory responses. We show in this study that both atorvastatin and simvastatin induced proinflammatory responses in mitogen-activated PBMCs by increasing the number of T cells secreting IFN-gamma. This is abolished by the presence of mevalonate, suggesting that statins act specifically by blocking the mevalonate pathway for cholesterol synthesis to promote the proinflammatory response. Both statins at low concentrations induced a dose-dependent increase in the number of IFN-gamma-secreting T cells in mitogen-activated PBMCs, whereas at higher concentrations the effect was abolished. The proinflammatory effect of statins was not seen in purified T cells per se activated with mitogen. However, conditioned medium derived from statin-treated PBMCs enhanced the number of IFN-gamma-secreting cells in activated purified T cells. This effect was not blocked by mevalonate, but was abolished by neutralizing Abs to IL-18 and IL-12. Similarly, the up-regulation of IFN-gamma-secreting T cells in PBMCs costimulated with statins and mitogens was blocked by the neutralizing anti-IL-18 and anti-IL-12. We showed that simvastatin stimulates the secretion of IL-18 and IL-1beta in monocytes. Active caspase-1, which is required for the processing and secretion of IL-18 and IL-1beta, was activated in simvastatin-treated monocytes. This was blocked by mevalonate and the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone. Taken together, the proinflammatory response mediated by statins in activated PBMCs is mediated mainly via the activation of caspase-1 and IL-18 secretion in the monocytes and to a lesser extent by IL-12.

Lipids, metabolic syndrome, and risk factors for future cardiovascular disease among HIV-infected patients

The availability of potent combination antiretroviral therapy has changed the long-term prognosis for people living with HIV/AIDS. There is increasing concern, however, about the effect of HIV therapy on lipid disorders and subsequent development of coronary artery disease. Virtually all classes of antiretroviral drugs have been associated with some aspect of atherogenic changes in the lipid profiles. This article reviews the current literature on HIV-associated dyslipidemias and the metabolic syndrome, their potential effect on future coronary heart disease, and reviews strategies for management.

Efficacy and Safety of Once-Daily Combination Therapy with Didanosine, Lamivudine and Nevirapine in Antiretroviral-Naive HIV-Infected Patients

Background

Simplified antiretroviral regimens are needed to improve patient adherence and quality of life. The purpose of this study was to evaluate the efficacy and safety of a once-daily regimen consisting of didanosine (ddI), lamivudine (3TC) and nevirapine (NVP) for adult antiretroviral-naive patients with HIV-1 infection.

Methods

This was a prospective, one-arm, multicentre pilot study. Daily drug dosage was 250 or 400 mg didanosine, 300 mg lamivudine and 400 mg nevirapine. The primary outcome measure was the percentage of patients with a plasma HIV-RNA level <50 copies/ml at 12 months on an intention-to-treat (ITT) basis.

Results

Seventy patients were enrolled in the study. At baseline, mean plasma HIV-1 RNA was 5.10 log10 copies/ml, and mean CD4 cell count was 262 cells/μl. At month 12, 67% (95% CI: 56–78) of patients maintained a viral load of <50 copies/ml in the ITT analysis and CD4 counts increased a median of 201 cells/μl. The treatment was more effective in patients with baseline CD4 counts >100 cells/μl than in those with a poorer immunological status at baseline, although the number of patients with CD4 counts <100 was low. Four patients died during the study period. Therapy was discontinued in 18 patients due to virological failure in 11, adverse events in seven, loss to follow-up or withdrawal of consent in four and death in one. Eight out of nine patients with available genotype after virological failure showed resistance mutations to NVP (Y181C and others) and 3TC (M184V/I), and four of them also had ddI resistance (L74V). The lipid profile was favourable, with a decrease in the ratio of total-to-high density lipoprotein cholesterol.

Conclusion

A once-daily combination of ddI, 3TC and NVP seems to be an effective, safe and easy-to-take regimen in antiretroviral-naive patients, at least in those who do not have severe immunodepression at baseline.

Substituting abacavir for hyperlipidemia-associated protease inhibitors in HAART regimens improves fasting lipid profiles, maintains virologic suppression, and simplifies treatment

Background

Hyperlipidemia secondary to protease inhibitors (PI) may abate by switching to anti-HIV medications without lipid effects.

Method

An open-label, randomized pilot study compared changes in fasting lipids and HIV-1 RNA in 104 HIV-infected adults with PI-associated hyperlipidemia (fasting serum total cholesterol >200 mg/dL) who were randomized either to a regimen in which their PI was replaced by abacavir 300 mg twice daily (n = 52) or a regimen in which their PI was continued (n = 52) for 28 weeks. All patients had undetectable viral loads (HIV-1 RNA <50 copies/mL) at baseline and were naïve to abacavir and non-nucleoside reverse transcriptase inhibitors.

Results

At baseline, the mean total cholesterol was 243 mg/dL, low density lipoprotein (LDL)-cholesterol 149 mg/dL, high density lipoprotein (HDL)-cholesterol 41 mg/dL, and triglycerides 310 mg/dL. Mean CD4+ cell counts were 551 and 531 cells/mm³ in the abacavir-switch and PI-continuation arms, respectively. At week 28, the abacavir-switch arm had significantly greater least square mean reduction from baseline in total cholesterol (-42 vs -10 mg/dL, P < 0.001), LDL-cholesterol (-14 vs +5 mg/dL, P = 0.016), and triglycerides (-134 vs -36 mg/dL, P = 0.019) than the PI-continuation arm, with no differences in HDL-cholesterol (+0.2 vs +1.3 mg/dL, P = 0.583). A higher proportion of patients in the abacavir-switch arm had decreases in protocol-defined total cholesterol and triglyceride toxicity grades, whereas a smaller proportion had increases in these toxicity grades. At week 28, an intent-to treat: missing = failure analysis showed that the abacavir-switch and PI-continuation arms did not differ significantly with respect to proportion of patients maintaining HIV-1 RNA <400 or <50 copies/mL or adjusted mean change from baseline in CD4+ cell count. Two possible abacavir-related hypersensitivity reactions were reported. No significant changes in glucose, insulin, insulin resistance, C-peptide, or waist-to-hip ratios were observed in either treatment arm, nor were differences in these parameters noted between treatments.

Conclusion

In hyperlipidemic, antiretroviral-experienced patients with HIV-1 RNA levels <50 copies/mL and CD4+ cell counts >500 cells/mm³, substituting abacavir for hyperlipidemia-associated PIs in combination antiretroviral regimens improves lipid profiles and maintains virologic suppression over a 28-week period, and it simplifies treatment.