Molecular mechanisms of HIV protease inhibitor-induced endothelial dysfunction

Recent developments regarding human immunodeficiency virus infection and stroke

Human immunodeficiency virus (HIV) infection is strongly associated with ischemic stroke in the young. Data obtained from the Nationwide Inpatient Sample in the United States show an increase in the number of stroke hospitalizations in the HIV-infected population despite an overall decrease in the number of stroke hospitalizations. Few data exist, however, that address the mechanism of HIV-associated stroke. Recent studies have demonstrated that HIV may infect the endothelium and alter cerebrovascular functions. Whether the proposed mechanism alters the stroke risk is undetermined. Epidemiological studies suggest that HIV-related stroke is associated with a risk factor profile that differs from the HIV-negative young stroke population in that HIV-associated strokes are less likely to have hypertension, diabetes, hyperlipidemia and smoking as risk factors. A large population-based study, moreover, suggests an association between antiretroviral therapy and increased cardio- and cerebrovascular risks. Specific antiretroviral agents such as protease inhibitors and non-nucleoside reverse transcriptase inhibitors have been implicated in the metabolic syndrome, accelerated atherosclerosis and an increased risk for ischemic stroke. In addition to discussing these developments, this paper also discusses the implications of recent data for stroke prevention in HIV-infected patients.

Association of HIV infection with spontaneous and iatrogenic preterm delivery: effect of HAART

OBJECTIVES

To assess the association between HIV infection and both spontaneous and iatrogenic preterm delivery (PTD), and to explore the impact of HAART on both entities.

METHODS

A matched retrospective cohort study was carried out on 517 HIV-infected pregnant women who consecutively attended a university referral hospital between 1986 and 2010. Two controls were assigned for each case. They were matched by ethnicity, smoking, maternal age and educational level. Exclusion criteria were multiple pregnancy and active injection drug use (IDU). PTD was defined as delivery less than 37.0 weeks. Spontaneous PTD included preterm premature rupture of membranes. Iatrogenic delivery was considered if medically indicated. Factors associated with PTD among HIV-infected women were analyzed by logistic regression.

RESULTS

A total of 1557 pregnant women were analyzed (519 HIV-infected and 1038 noninfected). The incidence of PTD was 19.7% in HIV-infected women and 8.5% in controls [odds ratio (OR) 2.6; 95% CI 1.9-3.6]. There was a significantly higher incidence of both spontaneous [adjusted OR (AOR) 2.1; 95% confidence interval (CI) 1.5-3.0] and iatrogenic prematurity (AOR 3.2; 95% CI 1.8-5.7). Iatrogenic PTD was significantly associated with the use of HAART during the second half of pregnancy, whereas spontaneous PTD was not related to HAART.

CONCLUSION

There is a significant association of HIV infection with PTD, both spontaneous and iatrogenic PTD. HAART use was predominantly associated with iatrogenic PTD.

Cardiovascular disease in HIV infection

PURPOSE OF REVIEW

Highly active antiretroviral therapy (HAART) use has markedly reduced AIDS-related mortality and opportunistic illness. With improved survival, cardiovascular disease (CVD) has emerged as an important noninfectious chronic comorbidity among antiretroviral (ARV)-treated HIV-infected persons.

RECENT FINDINGS

HIV infection can impact CVD and comorbidities known to increase CVD risk. Untreated HIV can cause proatherogenic elevations in serum lipids. Chronic HIV viremia results in increases in systemic inflammation, hypercoagulation, and reductions in endovascular reactivity, all of which are at least partially reversible with virally suppressive HAART. Chronic T-cell activation can also result in adverse vascular effects. Use of some ARV drugs can impact CVD risk by causing pro-atherogenic serum lipid elevations, induction of insulin resistance, increases in visceral adiposity or subcutaneous fat loss. Abacavir use may increase myocardial infarction risk by reducing vascular reactivity and/or increasing platelet activation. Traditional risk factors such as advancing age, smoking, hyperlipidemia, and hypertension remain important predictors of CVD among HAART-treated HIV-infected persons.

SUMMARY

HIV in the HAART era is a chronic manageable condition. CVD is an important cause of morbidity among HIV-infected persons. Untreated HIV can increase CVD risk in several ways and these effects are at least partially reversible with successful treatment. Use of specific ARVs can adversely impact CVD risk but the multiple long-term benefits of chronic HIV suppression and immune reconstitution achievable with potent HAART outweigh the adverse impact upon CVD risks that they may have. Standard CVD screening and risk-reducing interventions should be routinely undertaken for HIV-infected persons.

Premature Senescence of Vascular Cells Is Induced by HIV Protease Inhibitors

Objective— To determine whether and how protease inhibitors (PIs) could affect vascular aging.

Methods and Results— HIV therapy with PIs is associated with an increased risk of premature cardiovascular disease. The effect of ritonavir and a combination of lopinavir and ritonavir (for 30 days) on senescence, oxidative stress, and inflammation was evaluated in human coronary artery endothelial cells (HCAECs). These HCAECs were either cotreated or not cotreated with pravastatin or farnesyl transferase inhibitor (FTI)-277 or with 2 antioxidants (manganese [III] tetrakis [4-benzoic acid] porphyrin [MnTBAP] and N-acetyl cysteine). Senescence markers were evaluated in peripheral blood mononuclear cells (PBMCs) from HIV-infected patients under PI treatment. PIs induced senescence markers, prelamin A accumulation, oxidative stress, and inflammation in HCAECs. Senescence markers and prelamin A were also observed in PBMCs from HIV-infected patients under ritonavir-boosted PIs. Pravastatin, FTI-277, and antioxidants improved PI adverse effects in HCAECs. Senescence markers were lower in PBMCs from PI-treated patients cotreated with statins.

Conclusion— PIs triggered premature senescence in endothelial cells by a mechanism involving prelamin A accumulation. Accordingly, circulating cells from HIV-infected patients receiving PI therapy expressed senescence markers and prelamin A. Statin was associated with improved senescence in endothelial cells and patient PBMCs. Thus, PIs might promote vascular senescence in HIV-infected patients; and statins might exert beneficial effects in these patients.

Antiretroviral therapy with heart

Antiretroviral therapy (ART) has resulted in a substantial improvement in the morbidity and mortality associated with human immunodeficiency virus (HIV) infection. As this population ages, cardiovascular disease is becoming an increasingly important health burden. It is clear that many factors are involved in the development of this problem, with traditional risk factors (smoking, dyslipidemia, diabetes, family history, hypertension) the main contributors. ART and HIV infection itself can modify the risk of cardiovascular disease. Not only does this increased risk seem to be mediated through effects on traditional cardiovascular risk factors, namely dyslipidemia and insulin resistance, but there is also some evidence that HIV and ART may be associated with accelerated atherosclerosis and endothelial dysfunction. Current data are conflicting and further investigation into this area is needed. Drugs from both nucleoside reverse transcriptase inhibitor and protease inhibitor classes have been demonstrated to increase cardiovascular risk; however these effects are variable not only between classes but also between drugs in the same class. As newer therapies become available (in existing and new drug classes), the cardiovascular impact of these will need careful evaluation. Currently published guidelines suggest regular monitoring of cardiovascular risks (both before and after commencing ART) and pre-emptive treatment. Existing risk assessment tools have not been fully validated in an HIV setting and need to be used with caution. Lifestyle modification, in the first instance, and pharmacological intervention to reduce traditional risk factors are important management strategies. Initiating, or switching to, ART with a lower potential for metabolic derangement should also be considered.

Highly active antiretroviral therapy drugs inhibit in vitro cholesterol efflux from human macrophage-derived foam cells

We previously reported that HIV protease inhibitor, ritonavir, could inhibit cholesterol efflux and induce endothelial dysfunction. In this study, we further determined the effects and molecular mechanisms of a clinically relevant combination of highly active antiretroviral therapy (HAART) drugs on in vitro cholesterol efflux from human macrophage-derived foam cells. Foam cells derived from human monocyte cell line (THP-1) and periphery blood mononuclear cells (PBMCs) treated with HAART drugs including stavudine, didanosine and indinavir individually or in combination of three drugs (3-plex), followed by the initiation of cholesterol efflux with apolipoprotein A-I (apoA-I). Clinically relevant concentrations of HAART 3-plex significantly reduced cholesterol efflux in foam cells derived from THP-1 and PBMCs. HAART 3-plex significantly reduced the intracellular cholesterol transport molecule caveolin-1, whereas it increased superoxide anion production in THP-1 foam cells as compared with controls. Furthermore, mitochondrial membrane potential was significantly reduced, whereas the expression of NADPH oxidase subunit p67(phox) was increased in HAART 3-plex-treated macrophages. Consequently, antioxidants including ginsenosides Rb1 and Rg1, S-allyl cysteine sulphoxide (SACS), simvastatin (SVT) and vitamin E significantly abolished HAART 3-plex-induced inhibition of cholesterol efflux. Therefore, HAART drugs significantly inhibit cholesterol efflux from human macrophage-derived foam cells through downregulation of caveolin-1 and increase of oxidative stress.

Ginseng compounds: an update on their molecular mechanisms and medical applications

Ginseng is one of the most widely used herbal medicines and is reported to have a wide range of therapeutic and pharmacological applications. Ginsenosides, the major pharmacologically active ingredients of ginseng, appear to be responsible for most of the activities of ginseng including vasorelaxation, antioxidation, anti-inflammation and anti-cancer. Approximately 40 ginsenoside compounds have been identified. Researchers now focus on using purified individual ginsenoside to reveal the specific mechanism of functions of ginseng instead of using whole ginseng root extracts. Individual ginsenosides may have different effects in pharmacology and mechanisms due to their different chemical structures. Among them the most commonly studied ginsenosides are Rb1, Rg1, Rg3, Re, Rd and Rh1. The molecular mechanisms and medical applications of ginsenosides have attracted much attention and hundreds of papers have been published in the last few years. The general purpose of this update is to provide information of recently described effects of ginsenosides on antioxidation, vascular system, signal transduction pathways and interaction with receptors. Their therapeutic applications in animal models and humans as well as the pharmacokinetics and toxicity of ginsenosides are also discussed in this review. This review concludes with some thoughts for future directions in the further development of ginseng compounds as effective therapeutic agents.

Ginseng compounds: an update on their molecular mechanisms and medical applications

Ginseng is one of the most widely used herbal medicines and is reported to have a wide range of therapeutic and pharmacological applications. Ginsenosides, the major pharmacologically active ingredients of ginseng, appear to be responsible for most of the activities of ginseng including vasorelaxation, antioxidation, anti-inflammation and anti-cancer. Approximately 40 ginsenoside compounds have been identified. Researchers now focus on using purified individual ginsenoside to reveal the specific mechanism of functions of ginseng instead of using whole ginseng root extracts. Individual ginsenosides may have different effects in pharmacology and mechanisms due to their different chemical structures. Among them the most commonly studied ginsenosides are Rb1, Rg1, Rg3, Re, Rd and Rh1. The molecular mechanisms and medical applications of ginsenosides have attracted much attention and hundreds of papers have been published in the last few years. The general purpose of this update is to provide information of recently described effects of ginsenosides on antioxidation, vascular system, signal transduction pathways and interaction with receptors. Their therapeutic applications in animal models and humans as well as the pharmacokinetics and toxicity of ginsenosides are also discussed in this review. This review concludes with some thoughts for future directions in the further development of ginseng compounds as effective therapeutic agents.

The consequences of HIV infection and antiretroviral therapy use for cardiovascular disease risk: shifting paradigms

PURPOSE OF REVIEW

To explore the mechanisms by which HIV infection and antiretroviral therapy (ART) may increase risk for atherosclerotic cardiovascular disease (CVD), with attention to the implications of earlier initiation of ART (i.e. at higher CD4 cell counts than currently recommended by guidelines).

RECENT FINDINGS

Compared with the general population, HIV-infected patients who receive ART have a greater burden of subclinical and clinical atherosclerotic disease. Findings from a recent international treatment interruption trial (SMART) have redirected attention from ART-related drug toxicity toward a better appreciation for the consequences of untreated HIV infection, which may increase CVD risk through inflammation, upregulation of thrombotic pathways, and ultimately early vascular damage and dysfunction. In addition, CVD risk may increase with some ART, and this risk may be class-specific and/or drug-specific.

SUMMARY

Compared with untreated HIV, ART may increase or decrease risk of CVD. Reliable data on the relative risk do not exist. A randomized trial of early ART will provide the best data for assessment of the net risks and benefits of ART use on CVD.

Cardiovascular disease and HIV infection: host, virus, or drugs?

PURPOSE OF REVIEW

With effective antiretroviral therapy, cardiovascular disease has gained importance as a cause of morbidity and mortality in HIV-infected persons. We review the risk of cardiovascular disease in HIV-infected persons compared with that in uninfected persons and discuss the relative contributions of host, HIV, and antiretroviral therapy in the light of current knowledge.

RECENT FINDINGS

The incidence of cardiovascular disease in HIV-infected patients receiving antiretroviral therapy is low. However, the risk of cardiovascular disease increased compared with that in uninfected persons. This fact is substantially due to a higher prevalence of underlying traditional cardiovascular risk factors that are mostly host dependent. HIV may additionally contribute both directly through immune activation and inflammation, and indirectly through immunodeficiency. In a more modest way than that of HIV infection, the type of antiretroviral therapy may also contribute through its impact on metabolic and body fat parameters, and possibly through other factors that are currently unclear.

SUMMARY

Prevention of cardiovascular disease in HIV-infected patients should be standard of care. Traditional risk factors should be investigated and aggressively treated when possible. Antiretroviral therapy should be initiated earlier in patients with high cardiovascular risk. From a purely cardiovascular perspective, the benefits of antiretroviral therapy clearly outweigh any potential risk.

Non-nucleoside reverse transcriptase inhibitor efavirenz increases monolayer permeability of human coronary artery endothelial cells

Highly active antiretroviral therapy (HAART) is often associated with endothelial dysfunction and cardiovascular complications. In this study, we determined whether HIV non-nucleoside reverse transcriptase inhibitor efavirenz (EFV) could increase endothelial permeability. Human coronary artery endothelial cells (HCAECs) were treated with EFV (1, 5 and 10 microg/ml) and endothelial permeability was determined by a transwell system with a fluorescence-labeled dextran tracer. HCAECs treated with EFV showed a significant increase of endothelial permeability in a concentration-dependent manner. With real time PCR analysis, EFV significantly reduced the mRNA levels of tight junction proteins claudin-1, occludin, zonula occluden-1 and junctional adhesion molecule-1 compared with controls (P<0.05). Protein levels of these tight junction molecules were also reduced substantially in the EFV-treated cells by western blot and flow cytometry analyses. In addition, EFV also increased superoxide anion production with dihydroethidium and cellular glutathione assays, while it decreased mitochondrial membrane potential with JC-staining. Antioxidants (ginkgolide B and MnTBAP) effectively blocked EFV-induced endothelial permeability and mitochondrial dysfunction. Furthermore, EFV increased the phosphorylation of MAPK JNK and IkappaBalpha, thereby increasing NFkappaB translocation to the nucleus. Chemical JNK inhibitor and dominant negative mutant JNK and IkappaBalpha adenoviruses effectively blocked the effects of EFV on HCAECs. Thus, EFV increases endothelial permeability which may be due to the decrease of tight junction proteins and the increase of superoxide anion. JNK and NFkappaB activation may be directly involved in the signal transduction pathway of EFV action in HCAECs.

Left ventricular dysfunction in human immunodeficiency virus infection

The relationship between human immunodeficiency virus (HIV) infection and cardiovascular disease is still under debate, but it appears that the risk of myocardial infarction in those with HIV infection who are receiving highly active antiretroviral therapy (HAART) is increased. There has been less focus, however, on the effect of HIV and HAART on left ventricular function. Evidence from the past 20 years in both Westernized and developing countries has indicated that subclinical left ventricular dysfunction in HIV-infected individuals with and without well-controlled HIV infection is prevalent and may represent emerging cardiac disease. The specific roles of HIV infection and HAART are unclear, but they may exert independent direct and indirect effects on the myocardium. These effects may include chronic inflammation, metabolic complications (ie, insulin resistance, lipotoxicity, dyslipidemia), and mitochondrial toxicity. The objective of this article is to review the evidence for HIV- and HAART-related left ventricular dysfunction in persons infected with HIV.

Role of metabolic syndrome components in human immunodeficiency virus-associated stroke

Metabolic syndrome (MetS) is a cluster of risk factors, including elevated mean arterial pressure (MAP), atherogenic dyslipidemia (elevated triglycerides [TRG]), abdominal obesity (increased body mass index [BMI]), glucose intolerance (elevated glucose [GLU]), and prothrombotic/inflammatory state (increases in uric acid [UA]), that are associated with increased risk of cerebrovascular disease. We studied if an association existed between MetS components and human immunodeficiency virus (HIV)-associated cryptogenic strokes-those not caused by HIV complications, endocarditis, or stimulant abuse. We performed a retrospective case-control study. Eleven cryptogenic strokes were identified from 2346 HIV-infected (HIV+) participants. Each case was matched by age, sex, and date of stroke diagnosis to five HIV+ controls without stroke. Nonparametric stratified Wilcoxon ranked sum tests with subsequent mixed effect logistic regression determined the influence of each MetS component on HIV-associated cryptogenic stroke. Although each MetS component appeared higher for HIV+ cases with cryptogenic strokes than HIV+ controls, only MAP (odds ratio [OR] = 5.70, 95% confidence interval [CI] = 1.15-28.3) and UA (OR = 1.88, 95% CI = 1.06-3.32) were statistically different. A significantly higher percentage of HIV-associated cryptogenic stroke cases met criteria for MetS (4/11 = 36%) compared to HIV+ controls (6/55 = 11%). This observational study suggests a possible role for MetS components in HIV+ cryptogenic stroke cases. Although MetS is defined as a constellation of disorders, elevated hypertension and hyperuricemia may be involved in stroke pathogenesis. Reducing MetS component levels in HIV+ patients could therefore protect them from subsequent stroke.

Roles and mechanisms of human immunodeficiency virus protease inhibitor ritonavir and other anti-human immunodeficiency virus drugs in endothelial dysfunction of porcine pulmonary arteries and human pulmonary artery endothelial cells

The objective of this study was to determine the effects of highly active antiretroviral therapy (HAART) drugs on pulmonary endothelial function. Porcine pulmonary arteries or human pulmonary arterial endothelial cells (HPAECs) were incubated with eight HAART drugs [ritonavir, indinavir, lopinavir, zidovudine (AZT), abacavir, stavudine, didanosine (ddI), and lamivudine] individually or in combination [three HAART drugs (3-plex; indinavir, stavudine, and ddI)] at their clinical plasma concentrations for 24 hours. Endothelium-dependent vasorelaxation in response to bradykinin was reduced significantly by the ritonavir in a concentration-dependent manner. Five other HAART drugs (indinavir, lamivudine, abacavir, AZT, and ddI) and the 3-plex significantly also impaired endothelium-dependent vasorelaxation in response to bradykinin. Five HAART drugs (ritonavir, indinavir, lamivudine, abacavir, and AZT) significantly decreased endothelial nitric oxide synthase (eNOS) expression and increased superoxide anion levels in both vessels and HPAECs. Furthermore, both ritonavir and AZT substantially activated ERK2 in HPAECs. Additionally, the antioxidants ginsenoside Rb1 and ginkgolide A effectively reversed HAART drug-induced vasomotor dysfunction and eNOS down-regulation. Inhibition of ERK1/2 also partially blocked ritonavir- and AZT-induced down-regulation of eNOS and vasomotor dysfunction. Thus, HAART drugs significantly impair endothelial functions of porcine pulmonary arteries and HPAECs, which may be mediated by eNOS down-regulation, oxidative stress, and ERK1/2 activation. These findings suggest that HAART drugs may contribute to the high incidence of pulmonary artery hypertension in human immunodeficiency virus-infected patients.

Endothelial function in human immunodeficiency virus-infected antiretroviral-naive subjects before and after starting potent antiretroviral therapy: The ACTG (AIDS Clinical Trials Group) Study 5152s

OBJECTIVES

This study evaluated the effects of 3 class-sparing antiretroviral therapy (ART) regimens on endothelial function in human immunodeficiency virus (HIV)-infected subjects participating in a randomized trial.

BACKGROUND

Endothelial dysfunction has been observed in patients receiving ART for HIV infection.

METHODS

This was a prospective, multicenter study of treatment-naive subjects who were randomly assigned to receive a protease inhibitor-sparing regimen of nucleoside reverse transcriptase inhibitors (NRTIs) + efavirenz, a non-nucleoside reverse transcriptase inhibitor-sparing regimen of NRTIs + lopinavir/ritonavir, or a NRTI-sparing regimen of efavirenz + lopinavir/ritonavir. The NRTIs were lamivudine + stavudine, zidovudine, or tenofovir. Brachial artery flow-mediated dilation (FMD) was determined by B-mode ultrasound before starting on ART, then after 4 and 24 weeks.

RESULTS

There were 82 subjects (median age 35 years, 91% men, 54% white). Baseline CD4 cell counts and plasma HIV ribonucleic acid (RNA) values were 245 cells/mm(3) and 4.8 log(10) copies/ml, respectively. At baseline, FMD was 3.68% (interquartile range [IQR] 1.98% to 5.51%). After 4 and 24 weeks of ART, plasma HIV RNA decreased by 2.1 and 3.0 log(10) copies/ml, respectively. FMD increased by 0.74% (IQR -0.62% to +2.74%, p = 0.003) and 1.48% (IQR -0.20% to +4.30%, p < 0.001), respectively, with similar changes in each arm (Kruskal-Wallis p value >0.600). The decrease in plasma HIV RNA at 24 weeks was associated with greater FMD (r(s) = -0.30, p = 0.017).

CONCLUSIONS

Among treatment-naive individuals with HIV, 3 different ART regimens rapidly improved endothelial function. Benefits were similar for all ART regimens, appeared quickly, and persisted at 24 weeks.

HIV-related pulmonary arterial hypertension: clinical presentation and management

Pulmonary arterial hypertension (PAH) is a progressive albeit rare long-term complication of HIV infection, which has gained importance following the improved survival of HIV-infected patients with the use of HAART. The clinical and pathological findings in PAH associated with HIV infection (HIV-PAH) share many features with the idiopathic form of the disease. HIV-PAH is associated with a particularly poor prognosis and decreased survival compared with HIV-infected patients without this complication, and patients with HIV-PAH tend to die from the effects of PAH rather than as a result of their HIV infection. Prompt diagnosis and effective treatment of PAH in HIV-infected patients is therefore essential. There are currently only limited data regarding the efficacy of PAH therapies in HIV-PAH. Treatment with epoprostenol has been reported to provide benefit in some cases, but is associated with a range of problems linked to the need for continuous intravenous infusion. The dual endothelin receptor antagonist bosentan has proved to be effective in HIV-PAH without affecting the control of HIV infection, and has the benefit of oral administration. Other PAH therapies including prostacyclin analogs, phosphodiesterase type 5 inhibitors and selective endothelin receptor antagonists have yet to be trialed in this setting. Taking into account currently available data and clinical experience, a treatment algorithm for HIV-PAH based on that defined in treatment guidelines for other forms of PAH is suggested.

Platelet-leucocyte adhesion markers before and after the initiation of antiretroviral therapy with HIV protease inhibitors

INTRODUCTION

Thromboembolic complications under antiretroviral therapy (ART) have been described in the past. In particular, the influence of protease inhibitors (PIs) on platelet activation and coagulation is currently under discussion.

METHODS

HIV-1-infected, PI-naive adults (n = 18) were investigated before and 4 weeks after the start of the ART, consisting either of boosted PI regimens (n = 13) plus reverse transcriptase inhibitors (RTIs) or a double PI regimen (n = 5) without RTI co-medication. Administered PIs were saquinavir (n = 15), lopinavir (n = 4), fosamprenavir (n = 2) and atazanavir (n = 2). Platelet CD62P, CD40L (%+ cells) and PAC-1 binding [mean fluorescence intensity (MFI)] as well as monocyte CD11b (MFI) and monocyte-associated CD41 (%+ cells and MFI) expression were assessed by flow cytometry with or without platelet stimulation. To investigate the influence of platelets on coagulation, the endogenous thrombin potential (ETP) [render fluorescence units (RFI)] was determined.

RESULTS

CD62P, PAC-1 binding and CD11b expression remained unchanged. In contrast, the mean+/-SD MFI of CD40L (from 18.2+/-9.0 to 25.5+/-10.4, P = 0.038) and CD41 (from 446.1+/-213.8 to 605.0+/-183.8, P = 0.010) as markers for increased platelet-leucocyte interaction increased significantly. The collagen-induced ETP time-to-peak was altered significantly from 23.8+/-11.4 to 17.0+/-4.2 min (P = 0.028), although the ETP RFI peak showed no evidence for increased procoagulatory capacity (47.1+/-18.6 to 57.3+/-19.9, P = 0.085).

CONCLUSIONS

Effects of the evaluated PI HIV therapy on platelet function assessed under field conditions seem to be minor, not affecting all investigated parameters. We found no evidence for increased platelet activation under PI-containing ART. However, CD41 as a marker for increased platelet-leucocyte interaction and CD40L, which can contribute to atherosclerosis, increased significantly.

The roles of HIV-1 proteins and antiretroviral drug therapy in HIV-1-associated endothelial dysfunction

Since the emergence of highly active antiretroviral therapy (HAART), human immunodeficiency virus-1 (HIV-1)-infected patients have demonstrated dramatic decreases in viral burden and opportunistic infections, and an overall increase in life expectancy. Despite these positive HAART-associated outcomes, it has become increasingly clear that HIV-1 patients have an enhanced risk of developing cardiovascular disease over time. Clinical studies are instrumental in our understanding of vascular dysfunction in the context of HIV-1 infection. However, most clinical studies often do not distinguish whether HIV-1 proteins, HAART, or a combination of these 2 factors cause cardiovascular complications. This review seeks to address the roles of both HIV-1 proteins and antiretroviral drugs in the development of endothelial dysfunction because endothelial dysfunction is the hallmark initial step of many cardiovascular diseases. We analyze recent in vitro and in vivo studies examining endothelial toxicity in response to HIV-1 proteins or in response to the various classes of antiretroviral drugs. Furthermore, we discuss the multiple mechanisms by which HIV-1 proteins and HAART injure the vascular endothelium in HIV-1 patients. By understanding the molecular mechanisms of HIV-1 protein- and antiretroviral-induced cardiovascular disease, we may ultimately improve the quality of life of HIV-1 patients through better drug design and the discovery of new pharmacological targets.

Insulin resistance predicts endothelial dysfunction and cardiovascular risk in HIV-infected persons on long-term highly active antiretroviral therapy

OBJECTIVE

Cardiovascular disease risk among persons with HIV is likely multifactorial, thus testing a variety of available noninvasive vascular ultrasound and other surrogate tests may yield differing results. To address this issue, we assessed multiple metabolic and clinical predictors of endothelial function and carotid intima-media thickness in HIV-infected subjects and compared results with HIV-negative controls.

DESIGN

Prospective, cross-sectional study of 50 HIV-infected, healthy adults on stable highly active antiretroviral therapy matched to 50 HIV-negative controls by age, sex, race, and body mass index.

METHODS

Flow-mediated vasodilation of the brachial artery, carotid intima-media thickness, dual energy X-ray absorptiometry (HIV-infected subjects), and fasting insulin, lipids, and oral glucose tolerance tests were performed. Results were compared between HIV-infected and control groups.

RESULTS

Fifty percent of subjects were African-American with 34% women. Among HIV-infected, mean CD4 cell count was 547 cells/microl; 90% had HIV RNA less than 50 copies/ml. There were no significant differences between HIV-infected and control subjects with regard to brachial artery flow-mediated vasodilation or carotid intima-media thickness. In multivariate analyses of the HIV cohort, independent predictors of endothelial dysfunction (lower flow-mediated vasodilation) were increasing insulin resistance, greater alcohol consumption, and higher baseline brachial artery diameter (P < 0.05); predictors of increased carotid intima-media thickness were hypertension, higher trunk/limb fat ratio, and insulin resistance (P < 0.05).

CONCLUSION

In this HIV cohort on modern highly active antiretroviral therapy with well controlled HIV, there were no significant differences with regard to preclinical markers of cardiovascular disease. Insulin resistance was a strong predictor of impaired brachial artery flow-mediated vasodilation and increased carotid intima-media thickness, and may be an important cardiovascular disease risk factor in the HIV population.

Alterations in the Notch4 pathway in cerebral endothelial cells by the HIV aspartyl protease inhibitor, nelfinavir

Background

Aspartyl protease inhibitors (PIs) used to treat HIV belong to an important group of drugs that influence significantly endothelial cell functioning and angiogenic capacity, although specific mechanisms are poorly understood. Recently, PIs, particularly Nelfinavir, were reported to disrupt Notch signaling in the HIV-related endothelial cell neoplasm, Kaposi's sarcoma. Given the importance of maintaining proper cerebral endothelial cell signaling at the blood brain barrier during HIV infection, we considered potential signaling pathways such as Notch, that may be vulnerable to dysregulation during exposure to PI-based anti-retroviral regimens. Notch processing by γ-secretase results in cleavage of the notch intracellular domain that travels to the nucleus to regulate expression of genes such as vascular endothelial cell growth factor and NFκB that are critical in endothelial cell functioning. Since, the effects of HIV PIs on γ-secretase substrate pathways in cerebral endothelial cell signaling have not been addressed, we sought to determine the effects of HIV PIs on Notch and amyloid precursor protein.

Results

Exposure to reported physiological levels of Saquinavir, Indinavir, Nelfinavir and Ritonavir, significantly increased reactive oxygen species in cerebral endothelial cells, but had no effect on cell survival. Likewise, PIs decreased Notch 4-protein expression, but had no effect on Notch 1 or amyloid precursor protein expression. On the other hand, only Nelfinavir increased significantly Notch 4 processing, Notch4 intracellular domain nuclear localization and the expression of notch intracellular domain targets NFκB and matrix metalloproteinase 2. Pre-treatment with the antioxidant Vitamin E prevented PI-induced reactive oxygen species generation and partially prevented Nelfinavir-induced changes in both Notch 4 processing, and cellular localization patterns. Moreover, in support of increased expression of pro-angiogenic genes after Nelfinavir treatment, Nelfinavir did not inhibit angiogenic capacity.

Conclusion

Nelfinavir affects Notch 4 processing that results in induction of expression of the pro-angiogenic genes NFκB and matrix metalloproteinase 2 in cerebral endothelial cells.

Cardiovascular risk score change in HIV-1-infected patients switched to an atazanavir-based combination antiretroviral regimen

BACKGROUND

We aimed to establish whether the limited impact of atazanavir on the plasma lipid profile could translate into a reduction in the predicted cardiovascular risk in antiretroviral (ARV)-experienced patients switching to an atazanavir-containing regimen.

METHODS

HIV-1-infected treatment-experienced patients, switched to atazanavir for whatever reason and without prior major cardiovascular events, were selected and followed for at least 1 month. An individual cardiovascular risk score (10-year risk of major cardiovascular events) based on validated events and measurable risk factors in Italian cardiovascular cohorts was calculated using software available online.

RESULTS

A total of 197 patients were selected for inclusion in the study. After switching to atazanavir, the mean changes from pre-switch to last available measurement were -6.5% (P<0.001) for total cholesterol, -1.7% (P=0.029) for high-density lipoprotein (HDL) cholesterol, -11.3% (P<0.001) for non-HDL cholesterol and -8.6% (P<0.001) for triglycerides. The crude cardiovascular risk score was reduced from 3.43 to 3.38% (P=0.51); the analysis normalized by age showed a reduction from 3.43 to 3.14% (P<0.001). Subsets of patients with high baseline total cholesterol or triglycerides showed more marked reductions.

CONCLUSIONS

A treatment switch to atazanavir caused significant reductions in plasma lipids and a modest but significant reduction in the normalized-for-age cardiovascular risk score. Efforts should be made to concomitantly reduce the other preventable cardiovascular risk factors.

[Thromboembolic events at the time of highly active antiretroviral therapies against human immunodeficiency virus]

PURPOSE

Vein thrombosis risk and pulmonary embolism seem to be more important among human immunodeficiency virus (HIV) infected patients.

METHOD

We performed a retrospective study including 780 HIV positive patients followed-up between January 2000 and June 2005 at the University Hospital of Clermont-Ferrand.

RESULTS

Among the 780 HIV-infected patients, six cases of thromboembolic events were identified including, four with pulmonary embolism. All the patients were receiving lopinavir/ritonavir combination.

CONCLUSION

Although uncommon, pulmonary embolism occurs more frequently among HIV positive patients than in general population. Clinicians must remain aware about the possibility of the occurrence of a thromboembolic event especially during the first few months after introduction of the antiretroviral therapy.

How HIV protease inhibitors promote atherosclerotic lesion formation

PURPOSE OF REVIEW

One of the aims of this review is to summarize recent clinical approaches used to determine the role of HIV protease inhibitors in the development of cardiovascular disease. Another aim is to discuss possible molecular mechanisms whereby HIV protease inhibitors may promote atherogenesis.

RECENT FINDINGS

Several clinical studies have recently used ultrasonography to demonstrate increased intimal medial thickness and alterations in the structural characteristics of epi-aortic lesions in patients receiving HIV protease inhibitors. Molecular studies have indicated that several mechanisms are likely involved in mediating the effects of protease inhibitors. Possible mechanisms include inhibition of the proteasome, increased CD36 expression in macrophage, inhibition of lipoprotein lipase-mediated lipolysis, decreased adiponectin levels, and dysregulation of the NF-kappaB pathway.

SUMMARY

The currently available data strongly suggest that HIV protease inhibitors negatively impact the cardiovascular system. As is often the case with complex diseases like atherosclerosis it appears that HIV protease inhibitors affect the cardiovascular system through several distinct mechanisms by affecting various components of the arterial wall directly or indirectly by influencing lipoprotein and glucose metabolism of the body.

Key reports from the 9th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV 2007

The 9th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV provided a forum for the presentation of basic and clinical research focused on the pathogenesis and management of lipodystrophy and other adverse events associated with antiretroviral therapy. New data were reported on the contribution of both antiretroviral therapy and HIV infection itself on the development of metabolic abnormalities in patients with lipodystrophy, including insulin resistance and dyslipidaemia, which are associated with an increased risk of diabetes and cardiovascular disease. In addition, an emerging role of HIV and antiretroviral therapy in bone, liver and kidney disease were highlighted. A major focus of the data presented in these areas concerned the identification and evaluation of risk factors and appropriate surrogate markers for defining cardiovascular disease risk as well as other outcomes of long-term treatment. The complexity of defining such risk factors was underscored by data describing the impact of race, age and gender in the progression of metabolic disease and related complications among different HIV-infected populations. Finally, advances in the development of pharmacovigilance reporting systems in resource-limited settings and their impact upon healthcare policies and the provision of patient care were also described.