Asymptomatic atherosclerosis in HIV-positive patients: A case-control ultrasound study

Atherosclerosis and infection: is the jury still not in?

Atherosclerosis is a chronic inflammatory process accounting for increased cardiovascular and cerebrovascular morbidity and mortality. A wealth of recent data has implicated several infectious agents, mainly Chlamydophila pneumoniae, Helicobacter pylori, CMV and periodontal pathogens, in atherosclerosis. Thus, we sought to comprehensively review the available data on the topic, exploring in particular the pathogenetic mechanisms, and discuss anticipated future directions.

The expression of cholesterol metabolism genes in monocytes from HIV-infected subjects suggests intracellular cholesterol accumulation

BACKGROUND

Human immunodeficiency virus (HIV) infection is associated with increased cardiovascular risk and reduced high-density lipoprotein cholesterol (HDL-c). In vitro, HIV impairs monocyte-macrophage cholesterol efflux, a major determinant of circulating HDL-c, by increasing ABCA1 degradation, with compensatory upregulation of ABCA1 messenger RNA (mRNA).

METHODS

We examined expression of genes involved in cholesterol uptake, metabolism, and efflux in monocytes from 22 HIV-positive subjects on antiretroviral therapy (ART-Treated), 30 untreated HIV-positive subjects (ART-Naive), and 22 HIV-negative controls (HIV-Neg).

RESULTS

HDL-c was lower and expression of ABCA1 mRNA was higher in ART-Naive subjects than in both ART-Treated and HIV-Neg subjects (both P < .01), with HDL-c inversely correlated with HIV RNA (ρ = -0.52; P < .01). Expression of genes involved in cholesterol uptake (LDLR, CD36), synthesis (HMGCR), and regulation (SREBP2, LXRA) was significantly lower in both ART-Treated and ART-Naive subjects than in HIV-Neg controls.

CONCLUSIONS

In vivo, increased monocyte ABCA1 expression in untreated HIV-infected patients and normalization of ABCA1 expression with virological suppression by ART supports direct HIV-induced impairment of cholesterol efflux previously demonstrated in vitro. However, decreased expression of cholesterol sensing, uptake, and synthesis genes in both untreated and treated HIV infection suggests that both HIV and ART affect monocyte cholesterol metabolism in a pattern consistent with accumulation of intramonocyte cholesterol.

Fasting Triglyceride Concentrations are Associated with Early Mortality Following Antiretroviral Therapy in Zambia

BACKGROUND: In developing countries, 8 to 71% of patients initiating highly active antiretroviral therapy (HAART) die within the first year of treatment. Apart from baseline CD4 count, viral load, hemoglobin, BMI and stage of the disease, there may be other variables that contribute to AIDS-related mortality. We investigated the potential role of nutrition, lipids and insulin resistance-related phenotypes in predicting early mortality. METHODS: We recruited 210 HAART-naïve HIV/AIDS patients in Lusaka, Zambia. Dietary intake, anthropometric measurements, fasting serum insulin, glucose, and lipid profiles were assessed at baseline. Mortality was assessed after 90 days of follow-up. We used logistic regression models to identify variables associated with mortality. RESULTS: The mean±SD for age, BMI and CD4 count at baseline were 34±7.4 y, 20±3 kg/m(2) and 138±52 cells/μL, respectively. Sixteen patients (7.6%) died during follow-up. Triglyceride concentrations were associated with increased mortality [odds ratio (OR) for 1 mmol/L increase in triglyceride concentration=2.51; 95% CI: 1.34-4.71]. This association remained significant (OR=3.24; 95% CI: 1.51-6.95) after adjusting for age, gender, smoking, alcohol use, total cholesterol, BMI, CD4 count and n3 fatty acid intake. Apart from higher n3 fat intake which was inversely associated with mortality (survivors: 1.81±0.99% total energy/day vs. non-survivors 1.28±0.66% energy/day, P=0.04), there were no other macronutrients associated with mortality. CONCLUSION: Triglyceride concentrations at the time of initiating HAART are independently associated with increased risk for early mortality. If this association is confirmed in larger studies, assessment of triglycerides could become part of routine care of HIV patients initiating HAART in developing countries.

Therapy insight: Body-shape changes and metabolic complications associated with HIV and highly active antiretroviral therapy

Increasingly effective therapies for HIV infection are now available. These treatments, referred to collectively as highly active antiretroviral therapy, comprise various combinations of anti-HIV drugs from different drug classes. Recently, a range of metabolic complications have emerged as important toxicities in treated patients. Complications present as abnormalities of body-fat mass distribution in association with an often significant dyslipidemia and glucose homeostasis dysregulation. The body-shape changes, manifesting as peripheral lipoatrophy or central lipohypertrophy, can have a negative impact on quality of life and consequently on adherence to treatment. The combination of central lipohypertrophy, dyslipidemia and insulin resistance is associated with accelerated rates of atherosclerosis and other potentially significant long-term effects. The pathogenesis of these effects is complex and is still being actively investigated. Possible contributing factors relate to host characteristics, HIV viral parameters and specific effects of anti-HIV drugs on adipose-tissue biology and on intermediary metabolism. Management of these complications involves manipulation of the anti-HIV drugs using an understanding of their particular effects on lipid and glucose metabolism, in association with standard therapeutic interventions. Individualized approaches, taking into consideration quality-of-life issues, and assessment of potential cardiovascular risks, are now an important component of effective care of HIV-infected patients.

A retrospective study of the lipid-lowering efficacy and safety of ezetimibe added to hydroxy methylglutaryl coenzyme A reductase therapy in HIV-infected patients with hyperlipidemia

BACKGROUND

Abnormalities in lipid metabolism are a well-described consequence of human immunodeficiency virus (HIV) infection being treated with highly active antiretroviral therapies (HAART).

OBJECTIVE

The purpose of this study is to evaluate the lipid-lowering efficacy and safety of ezetimibe added to existing hydroxy methylglutaryl coenzyme A reductase (statin) therapy in HIV-infected patients with hyperlipidemia.

METHODS

This is a retrospective study utilizing a comprehensive electronic patient registry to identify all adult HIV-infected patients seen at the Dallas Veterans Affairs (VA) Medical Center during a 4-year period from October 1, 2002 through October 1, 2006.

RESULTS

A total of 26 HIV-infected patients initiated on ezetimibe 10 mg were identified, with 14 adult males meeting strict criteria for inclusion. Median age was 54 years (interquartile range [IQR], 45-59) with a median duration of HIV of 13 years, CD4 count of 513 cells/mm(3) (IQR, 289-736), and 9 of 14 patients had undetectable viral loads at baseline. Initiation of ezetimibe 10 mg resulted in a significant decrease in total cholesterol (TC) from baseline (-12.9%, P = 0.001); low-density lipoprotein cholesterol (LDL-C; -25.7%, P = 0.001); and non-high-density lipoprotein cholesterol (non-HDL-C; -23.9%, P = 0.001). There was also a nonsignificant decrease in triglycerides (15.8%, P = 0.43), and an increase in number of patients achieving National Cholesterol Education Program/Adult Treatment Panel III goal for LDL-C after initiation of ezetimibe (+20.9%, P = 0.125). These improvements occurred without adverse effects or changes in virologic and immunologic control.

CONCLUSION

Addition of ezetimibe to existing statin therapy in HIV-infected VA patients treated with HAART significantly reduces TC, LDL-C, and non-HDL-C concentrations without apparent side effects or compromising of virologic control.

Carotid intima?media thickness in HIV patients treated with antiretroviral therapy

INTRODUCTION

Increased cardiovascular risk in HIV patients in antiretroviral therapy (ART) may be due to HIV infection, direct effect of ART or dyslipidaemia induced by ART. Our aim was to study the relative importance of HIV, ART and dyslipidaemia on atherosclerosis, assessed by the comparison of carotid artery intima-media thickness (IMT) in non-smoking HIV patients with high or low serum cholesterol levels as well as in healthy volunteers.

METHODS

HIV patients in ART with normal cholesterol (<or=5 x 5 mmol l(-1); n=13) or high cholesterol (>or=6 x 5 mmol l(-1); n=12) as well as healthy controls (n=14) were included. All were non-smokers and had never received medication for dyslipidaemia or hypertension. IMT was measured by ultrasonography.

RESULTS

In HIV patients with normal cholesterol (<or=5 x 5 mmol l(-1)), in HIV patients with hypercholesterolaemia (>or=6 x 5 mmol l(-1)) and in controls (5 x 1 +/- 0 x 9 mmol l(-1)) IMT were 683 +/- 119, 656 +/- 99 and 657 +/- 99 microm, respectively. Thus no difference in IMT was found between the three groups. IMT values did not differ between patients receiving and not receiving protease inhibitors (658 +/- 117 microm versus 687 +/- 97 microm, P>0 x 05). In HIV patients IMT correlated inversely with HDL cholesterol levels (r=-0 x 50; P=0 x 01), whereas no correlation was found with total cholesterol or LDL cholesterol.

CONCLUSIONS

In non-smoking HIV patients receiving ART no sign of accelerated atherosclerosis was found as assessed by IMT even not in hypercholesterolaemic HIV patients. IMT correlated with HDL cholesterol but not with LDL cholesterol. Based on these observations, one could speculate whether selective lowering of LDL cholesterol will be successful in reducing cardiovascular risk in non-smoking HIV patients.

Venous and arterial thrombosis in patients with HIV infection

Thromboembolic complications in HIV-infected patients have been reported. To our knowledge, no case-control studies have compared the prevalence of thromboembolic events between HIV-positive and HIV-negative individuals. One hundred and sixty-nine HIV-infected patients and 180 randomly selected blood donors were enrolled. Selected patients completed a specific questionnaire and were subsequently interviewed. Information was collected on family and personal history of cardiovascular disorders and the presence of personal risk factors for venous and arterial thrombosis. All reported events were adjudicated only if adequate documentation of objective tests was available. Mean age and sex were similar in the two groups. A vascular event was documented in six HIV-infected patients (3.55%) and in none of the controls (P=0.0108). Family history of cardiovascular disorders, cigarette smoking and hypertriglyceridemia were more prevalent in HIV patients than in controls. In multivariate analysis, neither family traditional cardiovascular risk factors nor HIV infection were independently associated with the presence of thromboembolic events. The results confirm the hypothesis that HIV-positive patients have an increased risk of thromboembolic disorders. Whether this increased risk has been provoked by HIV infection itself or by other associated risk factors for cardiovascular events, such as cigarette smoking and hypertriglyceridemia, remain to be clarified.

Current Update on HIV-associated Vascular Disease and Endothelial Dysfunction

Highly active antiretroviral therapy (HAART) has greatly reduced the risk of early death from opportunistic infections and extended the lifespan of people infected with the human immunodeficiency virus (HIV). Thus, many complications and organic damage in the HIV-infected population emerge. Cardiovascular disease as coronary artery disease has become a matter of particular concern. Its incidence is greatly increased in the HIV-infected population over that of people of the same age in the absence of general cardiovascular risk factors. Despite several clinical and laboratory studies in the association between HIV infection and cardiovascular disease, the pathogenic mechanisms of this significant clinical problem are largely unknown and are now under active investigation. Endothelial dysfunction is possibly the most plausible link between HIV infection and atherosclerosis. Increased expression of adhesion molecules such as intercellular adhesion molecule (ICAM)-1 and endothelial adhesion molecule (E-selectin) and inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL-6 has been reported in HIV-positive patients. The effect of HAART on endothelial function in HIV-positive patients is also demonstrated. In this review, we focus on the recent research update of HIV-associated vascular disease and vascular injury. We analyze and discuss the recent clinical and laboratory investigations on the effect of HIV, viral protein, and HAART therapy on endothelial injury and vascular disease; identify the areas of controversy and clinical relevance; and suggest some directions for future research.

Macrolide use and the risk of vascular disease in HIV-infected men in the Multicenter AIDS Cohort Study

Background: There has been increasing concern that HIV-infected individuals may be more at risk for cardiovascular events in the highly-active antiretroviral therapy (HAART) era. This study examined the risk of thromboembolic events in HIV-infected and non-infected individuals and the effect of macrolide prophylaxis on those outcomes. Methods: A subcohort analysis was undertaken using data collected in the Multicenter AIDS Cohort Study to examine the relative risk of vascular events (myocardial infarction, unstable angina and ischaemic stroke). Cox proportional hazard model using age as the time scale with time varying cofactors obtained at each semi-annual visit were used to assess the independent effect of macrolide use. Results: Controlling for other significant effects including race and smoking, HIV-infection was not independently associated with vascular events. Increased risk was observed among those who used HAART (relative hazard 1.09, 95% confidence intervals 1.00–1.19 in multivariate model), antihypertensive treatment (1.81 [1.26–2.60]), lipid-lowering medication (1.65 [1.12–2.42]), and antibiotics (1.72 [1.25–2.36]). The protective association of macrolide use for a vascular event in the HAART era was also significant (0.10 [0.01–0.75]). Conclusions: Traditional risk factors are important in the pathogenesis of vascular events in HIV-infected individuals. Macrolide antibiotics may have a protective effect in the HIV-infected individuals in the HAART era.

Cardiovascular complications after renal transplantation and their prevention

By the time of renal transplantation, end-stage renal disease patients have a huge burden of cardiovascular disease (CVD) and are heavily saturated with atherosclerotic risk factors. Worsening of preexisting risk factors or new CVD risk factors may develop in the posttransplant period consequent in part to the diabetogenic and atherogenic potential of immunosuppressive drugs. The annual risk of a fatal or non-fatal CVD event of 3.5 to 5% in kidney transplant recipients is 50-fold higher than the general population. Renal allograft dysfunction, proteinuria, anemia, moderate hyperhomocysteinemia and elevated serum C-reactive protein concentrations, each dependently confer greater risk of CVD morbidity and mortality in the posttransplant period. Long-term care of renal transplant recipients should programmatically incorporate the recommendations of the National Kidney Foundation Working Groups and European Best Practice Guidelines Expert Group on Renal Transplantations into the management of hypertension, dyslipidemia, smoking, and posttransplant diabetes mellitus. Timely utilization of coronary revascularization procedures should be undertaken as these treatments are equally effective in the kidney transplant population.

Rapid progression of carotid lesions in HAART-treated HIV-1 patients

To obtain data on the evolution of carotid lesions, we evaluated 133 patients at their first antiretroviral regimen, followed for at least 2 years; 77 treated with protease inhibitors (PIs): Group A and 56 with non-nucleosidic reverse transcriptase inhibitors (NNRTIs): Group B. All patients were subjected to carotid ultrasonography. In Group A, among the previously normal patients 22.5% developed lesions, 40% remained normal, 37.5% shifted to other antiretroviral regimens. Among the 37 previously pathologic patients, 46% worsened, 19% were stable, in 8% the lesions had disappeared, 27% shifted. In Group B, among the previously normal patients, 12.7% developed lesions, 80.8% remained unaltered, 6.5% shifted. Among the previously pathologic patients, 12.5% worsened, lesions reversed in 25%, remained stable in 50% and 12.5% shifted to PI. At statistical analysis, in Group A both the percentage of patients developing new lesions and the percentage of patients who worsened was significantly higher. In conclusion, we evidenced a more rapid onset of lesions in patients treated with PIs with respect to patients treated with NNRTIs and towards a more rapid evolution of the previous lesions. The shift from PIs to NNRTI/3 NRTI seems related to a lower rate of evolution. Interestingly, a disappearance of lesions was detected in both groups.

Circulating markers of endothelial function in cardiovascular disease

Endothelial dysfunction is a key event in cardiovascular disease. Measurement of endothelial dysfunction in vivo presents a major challenge, but has important implications since it may identify the clinical need for therapeutic intervention, specifically in primary prevention. Several biological markers have been used as indicators of endothelial dysfunction. The soluble adhesion molecules sICAM-1 and sVCAM-1 lack specificity and are increased in inflammatory processes. Both markers are increased in coronary artery disease. sICAM-1 level predicts the risk for cardiovascular disease or diabetes mellitus in healthy individuals. sE-selectin is specific for the endothelium and is increased in coronary artery disease and diabetes mellitus. sE-selectin is also associated with diabetic risk. The endothelium-specific marker, soluble thrombomodulin, is associated with severity of coronary artery disease, stroke or peripheral occlusive arterial disease and is not increased in healthy or asymptomatic subjects. Interestingly, thrombomodulin decreases during treatment of hypercholesterolemia or hyperhomocysteinemia. In contrast, von Willebrand factor is the best endothelial biomarker and predicts risk for ischemic heart disease or stroke.

Dyslipidaemia and cardiovascular risk in HIV infection

Cardiovascular disease is increasingly recognised as a consequence of human immunodeficiency virus (HIV) infection in the era of highly active antiretroviral therapy (HAART). Dyslipidaemia is also a feature of HIV infection itself and the antiretroviral drugs from the protease inhibitor classes. Increased rates of atherosclerotic disease and diabetes have been associated with lipodystrophy and now from one of the major causes of morbidity in HIV and acquired immunodeficiency syndrome (AIDS).This review, based on a multi-database keyword search, summarises the lipid changes observed in the course of HIV infection and its treatment, and puts them into the context of other risk factors for cardiac disease, and other causes of cardiovascular disease in HIV.

Managing cardiovascular risk in patients with HIV infection

Highly active antiretroviral therapy (HAART) improves the survival of patients with HIV infection; however, several observational studies have described associations between HIV infection, HAART, and cardiovascular disease. Important limitations of these studies included a low incidence of cardiovascular events, short duration of HAART exposure, and retrospective design. Nevertheless, the weight of evidence from observational and surrogate end point studies suggests that the dyslipidemia and other metabolic changes that are common in patients with HIV infection and those using HAART may be associated with increased cardiovascular risk. The Infectious Disease Society of America/Adults AIDS Clinical Trials Group guidelines for the evaluation and management of dyslipidemia recommend target lipid levels and treatment of dyslipidemia in patients with HIV infection. Although practitioners should consider dyslipidemia and cardiovascular risk when making plans for initiating or altering HAART therapy, maintaining viremic control should be the overriding factor, because short-term absolute rates of cardiovascular disease are significantly lower than death rates from AIDS in inadequately suppressed patients. This article reviews the cardiovascular risks in patients receiving HAART and discusses the implementation of the new guidelines.

Chronic infection and coronary artery disease

On a variety of fronts, chronic infection has been found to be significantly associated with the development of atherosclerosis and the clinical complications of unstable angina, myocardial infarction, and stroke. For the most part, these relationships are still just associations. Failure to confirm initial reports of serologic associations also has been common. Specific causative relationships on par with that determined between H pylori and peptic ulcer disease have not yet been established. Potential mechanisms whereby chronic infections may play a role in atherogenesis are myriad. In the case of C pneumoniae, the effect may result from direct vessel wall colonization that may damage the vessel either directly or indirectly by initiating immunologic responses. In other cases the effect may simply be that of enhancing the pre-existing chronic inflammatory response of the body to standard risk factors such as hyperlipidemia. Even though the infectious agent may not directly infect the vessel wall, it may perform its critical role from afar. Chronic infection might also influence pre-existing plaque by enhancing T-cell activation or other inflammatory responses that may participate in the destabilization of the intimal cap. Hence chronic infection may play a role either in the initiation, progression, or the destabilization of atherosclerotic plaques. The infectious agents with the most evidence to support an etiologic role in atherosclerosis include C pneumoniae and cytomegalovirus. Evidence is mounting for a variety of other potential agents including other herpes viruses, influenza, other specific bacteria (such as M pneumoniae), and chronic infections with common bacterial agents (periodontal disease, chronic bronchitis, and chronic urinary tract infection, among others) [191]. Future studies are expected to elucidate further the pathophysiologic relationship between chronic infection and atherosclerosis and to evaluate further the potential of a variety of treatment approaches, including antibiotics.

Acute myocardial infarction in patients infected with human immunodeficiency virus

BACKGROUND

Recent clinical and post-mortem reports suggests that human immunodeficiency virus (HIV) infection may participate in the process of atherosclerosis independent of other coronary risk factors. In this prospective and observational study, we investigated whether an associative link exists between HIV infection and coronary artery disease.

METHODS

Of 690 patients admitted to our hospital in a 3-year period, 29 patients (28 men and 1 woman) with a mean age of 46 +/- 10 years had an acute myocardial infarction (AMI) on the basis of acute prolonged chest pain, ischemic electrocardiogram abnormalities, and elevated serum markers of myocardial necrosis at presentation.

RESULTS

ST-segment elevation MI was present in 15 patients, and non-ST-segment elevation MI was present in 14 patients. Twenty-two patients (76%) were <55 years; 17 of these patients had no or 1 coronary risk factor, and 5 patients had 2 or 3 risk factors. Five patients >55 years had 1 coronary risk factor, and 2 patients had 2 risk factors. Thirteen patients underwent a myocardial revascularization procedure, and 1 patient died during hospitalization.

CONCLUSIONS

HIV infection, as a cause of endothelial injury, may initiate the inflammatory process of early atherosclerosis and participate in the evolution of the atherothrombotic lesion responsible for AMI. This study suggests that the association of HIV infection and acute coronary syndrome may be more common than previously reported and underscores the need for further clinical studies.

Hiv Tat protein causes endothelial dysfunction in porcine coronary arteries

PURPOSE

Human immune deficiency virus (HIV) infection is often associated with chronic diseases, including atherosclerosis. However, the molecular mechanisms are largely unknown. We examined the effect of Tat protein, an HIV regulatory protein, on endothelial function in porcine coronary arteries.

METHODS

Porcine coronary arteries were dissected from nine pig hearts and cut into 5-mm ring segments, which were incubated as controls or with Tat protein (10(-7), 10(-9), 10(-11) mol/L) or Tat protein plus anti-Tat antibody, for 24 hours. Myography was performed with thromboxane A(2) analog U46619 (10 (-7) mol/L) for contraction and with graded doses of bradykinin (10(-8), 10(-7), and 10(-6) mol/L) or sodium nitroprusside (10(-5) mol/L) for relaxation. Endothelial nitric oxide synthase (eNOS) messenger RNA was determined with reverse transcriptase polymerase chain reaction (RT-PCR), and protein levels were determined with Western blot analysis. Immunoreactivity of eNOS of treated rings was also detected.

RESULTS

Endothelium-dependent vasorelaxation (10-7 mol/L of bradykinin) was significantly reduced (46.41%) in pig coronary artery rings treated with 10(-7) mol/L of Tat protein, as compared with control arteries (P <.05). Arteries treated with Tat protein plus anti-Tat antibody relaxed similarly as control arteries. There were no differences in smooth muscle contractility (U46619) or endothelium-independent vasorelaxation (sodium nitroprusside) between control and Tat protein-treated groups. RT-PCR for eNOS mRNA showed reduction in eNOS levels for Tat-treated coronary artery rings by 73%, as compared with control vessels (P <.05). Tat protein-treated vessels demonstrated substantially less eNOS protein band intensity and immunoreactivity compared with control vessels.

CONCLUSIONS

Tat protein significantly decreased endothelium-dependent vasorelaxation and eNOS mRNA and protein expression in endothelial cells of porcine coronary arteries. This study suggests that Tat protein-mediated endothelial dysfunction may be important in coronary heart disease in HIV-infected patients.

CD4 cell lymphopenia and atherosclerosis in renal transplant recipients

Several animal studies suggest that T cell-mediated immunodeficiency may play a role in the progression of atherosclerosis. This study examined the association between lymphocyte subsets and atherosclerotic events in renal transplant recipients. A total of 302 consecutive renal transplant recipients were enrolled in this prospective study. Peripheral blood lymphocyte subsets were quantified and analyzed with respect to other known cardiovascular risk factors. The patients were followed for a mean duration of 23.5 +/- 4.5 mo. Mean CD4, CD8, and CD19 cell levels were 511 +/- 290/mm(3), 553 +/- 596/mm(3), and 66 +/- 62/mm(3), respectively. CD4 levels were positively related to transplant duration (r = 0.32; P = 0.02) and inversely related to age (r = 0.35; P = 0.01). Twenty-five atherosclerotic events (AE) occurred in 25 patients (8.3%). CD4 levels were lower in patients who experienced CVE (288 +/- 170/mm(3) versus 531 +/- 290/mm(3); P < 0.0001). Cox regression analysis showed that patients in the three upper quartiles of CD4 cell count had a decreased risk of CVE compared with those in the lowest quartile. There was a linear increase in risk of CVE with decreasing CD4 cell count (P < 0.0001). A CD4 cell count in the highest quartile (>663/mm(3)) divided the risk of CVE by 10 as compared with the lowest quartile. In conclusion, CD4 lymphocytopenia is an independent risk factor for the development of cardiovascular complications in renal transplant recipients, suggesting that impaired immune response promotes accelerated atherogenesis in this population.

HIV-1 envelope glycoprotein 120 increases intercellular adhesion molecule-1 expression by human endothelial cells

Human immunodeficiency virus type 1 (HIV-1) infection is often associated with central nervous system damage and vascular complications. However, the mechanisms of this association are largely unknown. We examined the effect of HIV-1 envelope glycoprotein 120 (gp120) on cell adhesion molecule expression by endothelial cells. We found, for the first time, that both soluble and membrane-bound gp120 could significantly increase the expression of human endothelial intercellular adhesion molecule-1 (ICAM-1) at both mRNA and protein levels, but not vascular cell adhesion molecule-1 and E-selectin. The specificity of gp120-mediated response was demonstrated by blocking experiments using a specific monoclonal antibody against gp120, which successfully abolished the gp120-mediated increase of ICAM-1 expression. Furthermore, there was a significant increase of human monocytic cell line THP-1 adherence onto the gp120-treated endothelial monolayers. This increased cell adhesion was effectively blocked by either anti-gp120 or anti-ICAM antibodies. These findings suggest that HIV-1 gp120-mediated endothelial ICAM-1 expression could be one of the important mechanisms of HIV-1 pathogenesis.

Exercise stress testing for detection of silent myocardial ischemia in human immunodeficiency virus-infected patients receiving antiretroviral therapy

The prevalence of silent myocardial ischemia (SMI) and the factors associated with SMI were evaluated in patients infected with human immunodeficiency virus (HIV) who had been receiving highly active antiretroviral therapy (HAART) for > or =12 months and did not have known coronary artery disease or cardiac symptoms. Patients prospectively underwent exercise stress testing. The prevalence of SMI was 11% (11 of 99 patients). Patients who had SMI were significantly older than were patients who did not (mean+/-SD, 51+/-8 years vs. 42+/-9 years; P=0.001) and were more likely to have trunk obesity (54% of patients vs. 17%; P=.004). A significant correlation was found between a positive exercise test result and obesity (correlation,.006), waist-to-hip ratio (.007), and glucose and cholesterol levels (.04; P=.03). In multivariate analysis, age, central fat accumulation, and cholesterol level were independent variables associated with the detection of SMI. Exercise testing might be recommended for patients with HIV who have central fat accumulation and hypercholesterolemia.

Epidemiology of cardiovascular involvement in HIV disease and AIDS

The epidemiology of cardiac complications related to HIV including cardiomyopathy, increased left ventricular mass, myocarditis, pericardial effusion, endocarditis, and malignancy are discussed. A large number of HIV-infected individuals will present with cardiac complications in the next decade as chronic viral infection, co-infections, drug therapy, and immunosuppression affect the heart. Understanding the nature and course of cardiac illness related to HIV infection will allow appropriate monitoring, early intervention and therapy, and will provide a baseline to evaluate the effects of new therapeutic regimens such as highly active antiretroviral therapy on the cardiovascular system.

Coronary heart disease associated with the use of human immunodeficiency virus (HIV)-1 protease inhibitors: report of four cases and review

Four cases of human immunodeficiency virus (HIV)-infected patients who developed coronary heart disease (CHD) while under treatment with a protease inhibitor (PI) are described, and the epidemiologic and clinical features of 18 cases reported in the literature are analyzed. Cardiac manifestations mostly included myocardial infarctions. Smoking and hyperlipidemia were the most common risk factors for CHD, reported in 72 and 81% of the patients, respectively. Hypercholesterolemia was observed in 75% of the cases at the time of the cardiovascular event. Ninety percent of the patients with pretreatment normal lipid values experienced a rise in the plasma lipid levels during PI therapy. Although a definite relationship between the development of CHD and HIV PIs can not be made, this analysis suggests that PI-induced hyperlipidemia may play a role in accelerating coronary atherosclerosis in patients with concomitant risk factors. Evaluation and control of risk factors for CHD should be performed in each patient for whom treatment with a PI is indicated.

The effects of HIV infection on endothelial function

Endothelial dysfunction and/or injury is pivotal to the development of cardiovascular and inflammatory pathology. Endothelial dysfunction and/or injury has been described in Human Immunodeficiency Virus (HIV) infection. Elaboration of circulating markers of endothelial activation, such as soluble adhesion molecules and procoagulant proteins, occurs in HIV infection. Certain endothelial cells, such as those lining liver sinusoids, human umbilical vein endothelial cells, bone marrow stromal endothelial cells or brain microvascular endothelial cells, have been shown to be variably permissive for HIV infection. Entry of virus into endothelial cells may occur via CD4 antigen or galactosyl-ceramide receptors. Other mechanisms of entry including chemokine receptors have been proposed. Nevertheless, endothelial activation may also occur in HIV infection either by cytokines secreted in response to mononuclear or adventitial cell activation by virus or else by the effects of the secreted HIV-associated proteins, gp 120 (envelope glycoprotein) and Tat (transactivator of viral replication) on endothelium. Enhanced adhesiveness of endothelial cells, endothelial cell proliferation and apoptosis as well as activation of cytokine secretion have all been demonstrated. Synergy between select inflammatory cytokines and viral proteins in inducing endothelial injury has been shown. In HIV infection, dysfunctional or injured endothelial cells potentiate tissue injury, inflammation and remodeling, and accelerate the development of cardiovascular disease.

Sex differences in HAART-associated dyslipidaemia

OBJECTIVES

Because female sex protects against dyslipidaemia and atherosclerosis in normal subjects, we aimed to reveal potential sex differences in metabolic side-effects of a newly initiated highly active antiretroviral therapy (HAART) regimen, and to relate these changes to endothelial cell activation as measured by levels of circulating E-selectin (cE-selectin).

DESIGN

Prospective longitudinal cohort study.

SETTING

Tertiary care centre at a University Hospital.

METHODS

HIV-seropositive male (n = 27) and female patients (n = 13) with a plasma viral load of > or = 10 000 copies/ml and 35 healthy controls were enrolled in the study. All participants were weight stable, free of acute opportunistic infections, and had not taken any protease inhibitors before. Serum levels of lipids, insulin, leptin, and cE-selectin were measured before initiation of HAART, and at 3 and 6 months thereafter.

RESULTS

HAART increased serum levels of triglycerides, leptin, and low-density lipoprotein (LDL) cholesterol; these effects were more distinct in women. Fasting insulin levels and the LDL : high density lipoprotein (HDL) ratio increased only in female HIV-infected patients (P < 0.02 versus men). In contrast, endothelial activation, as measured by cE-selectin, decreased more in men (P < 0.02) than in women. As a consequence, women had higher triglycerides and leptin levels after therapy than did men, and the LDL : HDL ratio and cE-selectin levels, which were initially higher in men, were no longer different between the sexes.

CONCLUSIONS

Metabolic adverse effects during HAART are more pronounced in women than in men. Hence, female HIV-infected patients seem to loose part of their natural protection from atherosclerosis during antiretroviral therapy.

Premature atherosclerosis in HIV-infected individuals--focus on protease inhibitor therapy

OBJECTIVE

Lipid disorders associated with the use of protease inhibitors may contribute to the premature development of atherosclerosis. The purpose of the present study was to determine whether the administration of a protease inhibitor-containing regimen to middle-aged (30-50 years) HIV-infected individuals for 6 months or longer is associated with an increased prevalence of atherosclerosis.

METHODS

High-resolution B-mode ultrasound imaging was used to visualize the femoral and carotid arteries of 68 HIV-negative and 168 HIV-infected individuals, including 136 patients who had received protease inhibitors for 26.8 +/- 8.9 months (mean +/- SD). Atherogenic plaques were defined as a thickening of the intima-media > or = 1200 mm.

RESULTS

The proportion of participants with one or more plaques was higher in the HIV-infected group in comparison with the HIV-negative group (55 versus 38%; P = 0.02), and so was the prevalence of cigarette smoking (61 versus 46%; P = 0.03) and hyperlipidaemia (56 versus 24%; P < 0.001). The presence of plaque was independently associated with age, male gender, plasma low-density lipoprotein cholesterol levels and smoking. In univariate logistic regression analysis, an association was also found with HIV infection. Among HIV-infected subjects protease inhibitor therapy was not associated with the presence of plaque.

CONCLUSIONS

A large proportion of the middle-aged HIV-infected individuals examined during this study had one or more atherosclerotic plaques within the femoral or carotid arteries. The presence of peripheral atherosclerosis within this population is not associated with the use of protease inhibitors, but rather with 'classic' cardiovascular risk factors such as smoking and hyperlipidaemia, which are amenable to interventions.

Hypertension in the HIV-infected patient

HIV infection has reached endemic proportions in many African countries. In addition, HIV infection is a significant cause of renal dysfunction in the United States. HIV patients are at higher risk of developing hypertension at a younger age than the general population. Predisposing factors for developing hypertension include vasculitis in small, medium, and large vessels in the form of leukocytoclastic vasculitis, and aneurysms of the large vessels such as the carotid, femoral, and abdominal aorta with impairment of flow to the renal arteries. A syndrome of acquired glucocorticoid resistance has been described in patients with HIV with hypercortisolism and a lower affinity of the glucocorticoid receptors. The syndrome is characterized clinically by weakness, hypertension or hypotension, and skin pigmentation changes. Acute and chronic renal failure is often associated with HIV infection. The associated dysfunction in water and salt handling often induces hypertension. Finally, atherosclerosis has been described in young adults with HIV infection secondary to receiving highly active antiretroviral therapy.

Microorganisms in the aetiology of atherosclerosis

Recent publications have suggested that infective pathogens might play an important role in the pathogenesis of atherosclerosis. This review focuses on these microorganisms in the process of atherosclerosis. The results of in vitro studies, animal studies, tissue studies, and serological studies will be summarised, followed by an overall conclusion concerning the strength of the association of the microorganism with the pathogenesis of atherosclerosis. The role of the bacteria Chlamydia pneumoniae and Helicobacter pylori, and the viruses human immunodeficiency virus, coxsackie B virus, cytomegalovirus, Epstein-Barr virus, herpes simplex virus, and measles virus will be discussed.

Autoantibodies directed against phospholipids or human beta 2-glycoprotein I in HIV-seropositive patients: relationship with endothelial activation and antimalonic dialdehyde antibodies

BACKGROUND

We investigated the possible role of antiphospholipid (APA) and anti-human 2-glycoprotein I (beta2-GPI) antibodies (Ab) in thrombosis and atherosclerosis in human immunodeficiency (HIV)-positive patients, in whom they seem to be more frequent.

METHODS

We measured APA and anti-beta2-GPI Ab in 58 HIV-positive patients together with markers of disease progression, circulating beta2-GPI, plasma lipids, biological markers of endothelial activation and integrity (plasma thrombomodulin, von Willebrand factor, vascular cell adhesion molecule 1) and with antimalonic dialdehyde antibodies (anti-MDA Ab).

RESULTS

We found a 41% frequency of IgG APA in the HIV-positive patients. APA IgMs were rarely positive (7%), and anti-beta2-GPI IgGs were positive in 3-4% patients. There was no correlation between APA or anti-beta2-GPI Ab and the presence of opportunistic infections. Although plasma thrombomodulin, von Willebrand factor and vascular cell adhesion molecule 1 were significantly increased in the HIV-positive patients, APA was correlated only with vascular cell adhesion molecule 1, suggesting that APAs are correlated with endothelial activation but not with vascular endothelial lesions. A correlation between APA and anti-MDA IgG was demonstrated using multivariate analysis (r=0.542, P < 0.0001), suggesting a relationship between the targets of these antibodies. Finally, IgG APAs are frequent in HIV infection but are not correlated with biological markers of endothelial injury.

CONCLUSION

Our results do not support a role for APA or anti-beta2-GPI in HIV-associated silent vascular endothelial damage. However, the role of these autoantibodies in clinically relevant thrombotic events should be investigated in HIV-positive patients.