Pilot study of coronary atherosclerotic risk and plaque burden in HIV patients: 'a call for cardiovascular prevention'

Coronary Artery Calcification and Plaque Characteristics in People Living With HIV: A Systematic Review and Meta-Analysis

Background

Studies have reported that people living with HIV have higher burden of subclinical cardiovascular disease, but the data are not adequately synthesized. We performed meta‐analyses of studies of coronary artery calcium and coronary plaque in people living with HIV.

Methods and Results

We performed systematic search in electronic databases, and data were abstracted in standardized forms. Study‐specific estimates were pooled using meta‐analysis. 43 reports representing 27 unique studies and involving 10 867 participants (6699 HIV positive, 4168 HIV negative, mean age 52 years, 86% men, 32% Black) were included. The HIV‐positive participants were younger (mean age 49 versus 57 years) and had lower Framingham Risk Score (mean score 6 versus 18) compared with the HIV‐negative participants. The pooled estimate of percentage with coronary artery calcium >0 was 45% (95% CI, 43%–47%) for HIV‐positive participants, and 52% (50%–53%) for HIV‐negative participants. This difference was no longer significant after adjusting for difference in Framingham Risk Score between the 2 groups. The odds ratio of coronary artery calcium progression for HIV‐positive versus ‐negative participants was 1.64 (95% CI, 0.91–2.37). The pooled estimate for prevalence of noncalcified plaque was 49% (95% CI, 47%–52%) versus 20% (95% CI, 17%–23%) for HIV‐positive versus HIV‐negative participants, respectively. Odds ratio for noncalcified plaque for HIV‐positive versus ‐negative participants was 1.23 (95% CI, 1.08–1.38). There was significant heterogeneity that was only partially explained by available study‐level characteristics.

Conclusions

People living with HIV have higher prevalence of noncalcified coronary plaques and similar prevalence of coronary artery calcium, compared with HIV‐negative individuals. Future studies on coronary artery calcium and plaque progression can further elucidate subclinical atherosclerosis in people living with HIV.

Coronary Artery Disease in HIV-Infected Patients: Downside of Living Longer

PURPOSE OF REVIEW

Introduction of combination antiretroviral therapy (ART) has increased the life expectancy of patients with HIV infection, allowing them to live longer with this chronic medical condition and consequently experiencing conditions such as cardiovascular diseases (CVDs). Several studies have investigated the increased risk of CVD in people living with HIV (PLWH). However, less is known about the exact mechanisms involved in this increased risk. Also, specific guidelines for management of CVD in PLWH have not been developed yet. In this article, we review the recent literature on the mechanisms involved in pathogenesis of CVD in PLWH, with an emphasis on coronary artery disease (CAD).

RECENT FINDINGS

Although initial studies suspected the increased prevalence of traditional CVD risk factors and side effects of ART to be involved in the increased CVD risk in PLWH, recent studies have uncovered the important role of chronic persistent inflammation in this increased risk. In addition, biomarkers of inflammation have been associated with both CVD events and subclinical CAD in this population. Lastly, recent studies and ongoing clinical trials have been investigating medical interventions that aim to reduce inflammation and cardiovascular events. Different mechanisms of inflammation have been examined in PLWH, including subclinical viremia, microbial translocation, and coinfection with other pathogens such as cytomegalovirus. Although inflammatory biomarkers have been consistently associated with CVD and subclinical CVD outcomes, their prognostic value is unknown. Recent and ongoing trials are exploring the benefits of anti-inflammatory drugs, statins, and antimicrobial translocation drugs on both inflammation and CVD risk among PLWH.

Pharmacokinetic, Pharmacogenetic, and Other Factors Influencing CNS Penetration of Antiretrovirals

Neurological complications associated with the human immunodeficiency virus (HIV) are a matter of great concern. While antiretroviral (ARV) drugs are the cornerstone of HIV treatment and typically produce neurological benefit, some ARV drugs have limited CNS penetration while others have been associated with neurotoxicity. CNS penetration is a function of several factors including sieving role of blood-brain and blood-CSF barriers and activity of innate drug transporters. Other factors are related to pharmacokinetics and pharmacogenetics of the specific ARV agent or mediated by drug interactions, local inflammation, and blood flow. In this review, we provide an overview of the various factors influencing CNS penetration of ARV drugs with an emphasis on those commonly used in sub-Saharan Africa. We also summarize some key associations between ARV drug penetration, CNS efficacy, and neurotoxicity.

Inflammatory Markers Associated With Subclinical Coronary Artery Disease: The Multicenter AIDS Cohort Study

Background

Despite evidence for higher risk of coronary artery disease among HIV+ individuals, the underlying mechanisms are not well understood. We investigated associations of inflammatory markers with subclinical coronary artery disease in 923 participants of the Multicenter AIDS Cohort Study (575 HIV+ and 348 HIV− men) who underwent noncontrast computed tomography scans for coronary artery calcification, the majority (n=692) also undergoing coronary computed tomography angiography.

Methods and Results

Outcomes included presence and extent of coronary artery calcification, plus computed tomography angiography analysis of presence, composition, and extent of coronary plaques and severity of coronary stenosis. HIV+ men had significantly higher levels of interleukin‐6 (IL‐6), intercellular adhesion molecule‐1, C‐reactive protein, and soluble‐tumor necrosis factor‐α receptor (sTNFαR) I and II (all P<0.01) and a higher prevalence of noncalcified plaque (63% versus 54%, P=0.02) on computed tomography angiography. Among HIV+ men, for every SD increase in log‐interleukin‐6 and log intercellular adhesion molecule‐1, there was a 30% and 60% increase, respectively, in the prevalence of coronary stenosis ≥50% (all P<0.05). Similarly, sTNFαR I and II in HIV+ participants were associated with an increase in prevalence of coronary stenosis ≥70% (P<0.05). Higher levels of interleukin‐6, sTNFαR I, and sTNFαR II were also associated with greater coronary artery calcification score in HIV+ men (P<0.01).

Conclusions

Higher inflammatory marker levels are associated with greater prevalence of coronary stenosis in HIV+ men. Our findings underscore the need for further study to elucidate the relationships of inflammatory pathways with coronary artery disease in HIV+ individuals.

Coronary Heart Disease Risk, Dyslipidemia, and Management in HIV-Infected Persons

Dyslipidemia and coronary heart disease (CHD) are of increasing concern in persons with human immunodeficiency virus (HIV) infection who are living longer because of the benefits of highly active antiretroviral therapy (HAART). All classes of drugs used in HAART have been associated with atherogenic changes in lipid profiles. The management of HIV-infected persons with dyslipidemia and/or CHD currently emphasizes the importance of monitoring and optimizing lipid levels through lifestyle changes, switching antiretrovirals (ARVs), and lipid-lowering treatments utilizing guidelines developed for persons without HIV infection. In HIV-infected persons, the use of lipid-lowering drugs may result in pharmacokinetic interactions with ARVs, complicating the management of patients. Recent advances in our understanding of the differential effects of specific ARVs on lipids is beginning to alter the clinical approach to management. In the absence of randomized clinical trials, clinicians should aggressively treat atherogenic dyslipidemia by primarily utilizing or switching to ARVs with the lowest potential to induce CHD or, when this is not possible or is ineffective, secondarily by the addition of lipid-lowering therapy. The current optimal management of HIV infection requires careful selection of ARVs with consideration given to the potential development of CHD and an understanding of how to manage dyslipidemia.

Lipoprotein-associated phospholipase A2, a novel cardiovascular inflammatory marker, in HIV-infected patients

BACKGROUND

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an emerging biomarker of cardiovascular disease. This study was conducted to describe the distribution of Lp-PLA2 in a cohort of human immunodeficiency virus (HIV)-infected adults and to determine associations between Lp-PLA2, cardiometabolic risk factors, and subclinical atherosclerosis in this population.

METHODS

Lp-PLA2 was assessed in 341 (25% women, 52% white, 74% on highly active antiretroviral therapy [HAART]) participants of a cohort with detailed characterization of atherogenic risk factors, including surrogate markers of carotid and coronary atherosclerosis.

RESULTS

Mean Lp-PLA2 mass was 313 ± 105 ng/mL and activity 173 ± 49 nmol/minute/mL. Seventy-five percent of participants had abnormal Lp-PLA2. Those in the highest Framingham Risk Score tertile had significantly higher Lp-PLA2 activity. Participants with abnormal carotid intima-media thickness (cIMT) had higher Lp-PLA2 mass and activity. Those with coronary artery calcium (CAC) scores >100 had significantly higher Lp-PLA2 mass than those with lower or nondetectable calcium. Those on HAART and protease inhibitor (PI)-based treatment had significantly higher Lp-PLA2 mass and activity than those who were treatment-naive or not on PIs. In multivariate regression, HAART and PI use were positively associated with Lp-PLA2 activity and mass after adjusting for age, race, sex, low-density and high-density lipoprotein cholesterol levels, triglyceride level, and smoking. Adding Lp-PLA2 activity tertiles to the model improved the predictive value for abnormal common cIMT, but not internal cIMT or CAC score.

CONCLUSIONS

Lp-PLA2 is highly abnormal in HIV-infected patients and is associated with several cardiovascular and HIV treatment-specific risk factors. Lp-PLA2 may be used as an additional and more vascular specific biomarker for cardiovascular risk stratification in HIV-positive patients.

Metabolic disorders and cardiovascular consequences of HIV infection and antiretroviral therapy

Metabolic disturbances associated with HIV disease have become an important factor in patient management and have important implications for long-term outcomes, both in regards to mortality and healthcare burden. Recent research has implicated both HIV infection itself and specific antiretroviral therapies in the development of these disorders. This review examines recent findings from research into insulin and glucose dysregulation, serum lipid abnormalities, adipose tissue and derangements in bone metabolism. This review then describes the cardiovascular consequences and management of these metabolic disorders, and summarizes current thinking on the pathogenesis and effects of antiretroviral therapy. Finally, the review raises some questions regarding ongoing challenges and unmet needs in this field of research.

Fatty liver disease is associated with underlying cardiovascular disease in HIV-infected persons(*)

BACKGROUND

Cardiovascular disease is an increasing concern among HIV-infected persons and their providers. We determined if fatty liver disease is a marker for underlying coronary atherosclerosis among HIV-infected persons.

METHODS

We performed a cross-sectional study in HIV-infected adults to evaluate the prevalence of and factors, including fatty liver disease, associated with subclinical coronary atherosclerosis. All participants underwent computed tomography for determination of coronary artery calcium (CAC; positive defined as a score >0) and fatty liver disease (defined as a liver-to-spleen ratio <1.0). Factors associated with CAC were determined using multivariate logistic regression models.

RESULTS

We included in the study 223 HIV-infected adults with a median age of 43 years [interquartile range (IQR) 36-50 years]; 96% were male and 49% were Caucasian. The median CD4 count was 586 cells/μL and 83% were receiving antiretroviral medications. Seventy-five (34%) had a positive CAC score and 29 (13%) subjects had fatty liver disease. Among those with CAC scores of 0, 1-100 and >100, the percentage with concurrent fatty liver disease was 8, 18 and 41%, respectively (P=0.001). In the multivariate model, CAC was associated with increasing age [odds ratio (OR) 4.3 per 10 years; P<0.01], hypertension (OR 2.6; P<0.01) and fatty liver disease (OR 3.8; P<0.01).

CONCLUSIONS

Coronary atherosclerosis as detected using CAC is prevalent among young HIV-infected persons. The detection of fatty liver disease among HIV-infected adults should prompt consideration of assessment for underlying cardiovascular disease and risk factor reduction.

Increased coronary artery calcium score and noncalcified plaque among HIV-infected men: relationship to metabolic syndrome and cardiac risk parameters

OBJECTIVE

In this study, the effects of traditional cardiac risk factors on coronary artery calcium (CAC) score and presence of plaque, including noncalcified plaque, measured by computed tomography coronary angiography, were compared among HIV-infected and non-HIV-infected subjects, with respect to the presence of the metabolic syndrome (MS).

DESIGN AND METHODS

HIV-infected men recruited for the presence of the MS (HIV + MS, n = 27) were compared with 2 control groups, HIV-infected men recruited without regard to metabolic criteria (HIV, n = 87), and HIV-negative control men (C, n = 40), also recruited without regard to any metabolic criterion.

RESULTS

All 3 groups were similar in age, demographic parameters, and smoking. MS was seen in 100% of the HIV + MS group, compared with 28% in the HIV-infected control group and 11% in the HIV-negative controls. HIV + MS subjects had higher mean CAC score than HIV-infected controls (72 ± 25 vs. 30 ± 8, P = 0.04, HIV + MS vs. HIV) and HIV-negative controls (72 ± 25 vs. 18 ± 7; P = 0.02, HIV + MS vs. C). With respect to CAC, only the HIV + MS group had increased CAC compared with non-HIV. In contrast, both HIV groups demonstrated an increased prevalence of plaque [63% vs. 38%, P = 0.04 (HIV + MS vs. C) and 59% vs. 38%, P = 0.02, (HIV vs. C)] and increased number of noncalcified plaque segments compared with the HIV-negative group [1.26 ± 0.31 vs. 0.45 ± 0.16, P = 0.01 (HIV + MS vs. C); 1.02 ± 0.18 vs. 0.45 ± 0.16, P = 0.04 (HIV vs. C)]. Plaque and noncalcified plaque did not differ significantly between the HIV groups.

CONCLUSIONS

Metabolic abnormalities in HIV patients are specifically associated with increased coronary artery calcification, whereas HIV itself or other factors may be associated with the development of noncalcified lesions.

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.

Vascular dysfunction and cardiovascular complications

PURPOSE OF REVIEW

Antiretroviral (ARV) therapy has altered the course of HIV disease and dramatically increased the lifespan of HIV-infected individuals. Accumulating evidence, however, suggests that prolonged ARV use contributes to metabolic and cardiovascular changes. Understanding the toxicities of ARV treatment and sequelae of long-term infection is critical. This review will examine recent evidence related to vascular dysfunction and cardiovascular complications in HIV infection.

RECENT FINDINGS

Recent studies investigating circulating markers of inflammation, surrogate markers of subclinical atherosclerotic disease, and novel imaging modalities suggest the presence of endothelial dysfunction in HIV-infected patients. In addition, data from several recently updated cohort studies confirm an association between ARV therapy and cardiovascular events.

SUMMARY

New data suggest that cardiovascular disease is increased among HIV-infected patients receiving highly active ARV therapy. The mechanisms of increased cardiovascular disease may relate to direct effects of the HIV virus and inflammation on the vasculature or to toxicities from specific ARV therapies, which may increase traditional cardiovascular risk factors. Understanding and modifying these risks and preventing cardiovascular events are critical to the long-term management of the HIV-infected patient.

Cardiovascular complications in HIV-infected individuals

PURPOSE OF REVIEW

This review updates the relationship between HIV and cardiovascular abnormalities in the context of the pathophysiology of coronary artery disease.

RECENT FINDINGS

The evaluation of cardiovascular risk in patients with HIV hinges upon a complex interplay of direct and indirect vascular effects of HIV infection, antiretroviral therapy, aging, and exposure to cardiovascular risk factors. Carotid artery intima-media thickness and endothelial-dependent flow-mediated vasodilatation of the brachial artery, which gives an indication of the structural and functional aspect of the endothelium as well as soluble biomarkers, can help to assess the potential harm and benefits of antiretroviral drugs and address the residual burden of cardiovascular risk in the HIV population.

SUMMARY

Given the complex pathophysiology of cardiovascular disease, no single biomarker is likely to be able to provide a universal surrogate whereby change observed independently predicts benefit, increased risk, or no effect across all drugs and mechanistic targets. Investigations and treatments must be tailored in the single patient according to non-modifiable and modifiable risk factors, including exposure to highly active antiretroviral therapy. With proper risk stratification altering the approach to highly active antiretroviral therapy, lifestyle changes, and lipid-lowering medications are the basis for reducing cardiovascular risk in HIV-infected patients.

Cardiovascular complications and atherosclerotic manifestations in the HIV-infected population: type, incidence and associated risk factors

Before the introduction of successful antiretroviral therapy (ART), cardiovascular complications in HIV-infected patients were largely those resulting from immunosuppression (e.g. myocarditis, pericarditis, tamponade). With the advent of ART, there has been a spectacular decrease in morbidity and mortality in HIV-infected individuals. However, alongside metabolic complications caused by ART such as insulin resistance, dyslipidemia and lipodystrophy syndrome have been observed, which potentially increase the risk of cardiovascular complications, in particular coronary artery disease. Whether HIV infection and ART are independent and individual coronary risk factors is still controversial. More and more data are available demonstrating that increasing the duration of exposure to ART, and in particular protease inhibitors, increases the risk of myocardial infarction. At the same time, chronic infection, inflammation and the disruption of immune balance as a result of HIV infection itself may have the potential to alter vascular structure and function. In this article, we will review cardiovascular complications in HIV-infected patients before and after the advent of ART, focusing on coronary artery disease, its diagnosis, prognosis and therapy.

Subclinical coronary atherosclerosis, HIV infection and antiretroviral therapy: Multicenter AIDS Cohort Study

OBJECTIVE

To evaluate the association of HIV infection and cumulative exposure to highly active antiretroviral therapy (HAART) with the presence and extent of coronary artery calcification (CAC).

DESIGN

A cross-sectional study of 947 male participants (332 HIV-seronegative, 84 HAART-naive and 531 HAART-experienced HIV-infected) from the Multicenter AIDS Cohort Study.

METHODS

The main outcome was CAC score calculated as the geometric mean of the Agatston scores of two computed tomography replicates. Presence of CAC was defined as calcification score above 10, and extent of CAC by the score for those with CAC present. Multivariable regression was used to evaluate the association between HIV infection and HAART and presence and extent of calcification.

RESULTS

Increasing age was most strongly associated with both prevalence and extent of CAC for all study groups. After adjustment for age, race, family history, smoking, high-density lipoprotein-C, low-density lipoprotein-C and hypertension, HIV infection (odds ratio, 1.35; 95% confidence interval, 0.70, 2.61) and long-term HAART use (odds ratio, 1.33; 95% confidence interval, 0.87, 2.05) increased the odds for presence of CAC. In contrast, after adjustment for these covariates, the extent of CAC was lower among HAART users. Among those not taking lipid-lowering therapy, HAART usage of at least 8 years was associated with significantly reduced CAC scores (relative CAC score, 0.43; 95% confidence interval, 0.24, 0.79).

CONCLUSION

HAART use may have different effects on the presence and extent of coronary calcification. Although prevalence of calcification was marginally increased among long-term HAART users, the extent of calcification was significantly reduced among HAART users compared with HIV-seronegative controls.

Coronary atherosclerotic lesions in human immunodeficiency virus-infected patients: a histopathologic study

BACKGROUND

Studies suggest human immunodeficiency virus-positive (HIV+) patients have an increased risk of coronary artery disease (CAD), yet little is known about the histopathology, severity, or distribution of lesions.

METHODS

The coronary arteries of 66 deceased AIDS patients and 19 HIV controls (age <55) were dissected and graded for percent luminal stenosis by intimal lesions, percent of intima involved with lipid, and extent of intimal calcification on a scale of 0 to 3. Medical histories, antiretroviral therapies, and CAD risk factors were reviewed.

RESULTS

HIV+ patients were older than controls (P=.06), and more were male (P=.02). Thirty-five percent of HIV+ patients had stenosis >or=75% of at least one artery. Compared to controls, HIV+ patients had three times greater odds of stenosis >or=75%, controlling for age and sex (one-sided P=.03). Older age and male sex were also risk factors (one-sided P<.001). HIV seropositivity was associated with increased plaque lipid content (one-sided P=.02) and calcification (one-sided P=.08). Duration of HIV infection, antiretroviral therapy, and immune status did not predict severe disease in multivariate analyses. Previously unreported patterns of dystrophic calcification were observed in HIV+ patients and older controls.

CONCLUSIONS

Young to middle-aged patients dying from advanced AIDS have atherosclerotic CAD that may result in luminal narrowing, heavy calcification, and high plaque lipid content. The pattern of disease, location of lesions, and plaque composition are typical of atherosclerosis in HIV-negative patients. No relationship between antiretroviral therapies and atherosclerosis was seen in this small study of heavily treated patients.

Metabolic syndrome and subclinical atherosclerosis in patients infected with HIV

BACKGROUND

The present study examines the association between carotid and coronary atherosclerosis and metabolic syndrome in human immunodeficiency virus (HIV)-infected adults.

METHODS

We measured the common and internal carotid intima-media thickness (c-IMT) using B-mode ultrasonography, and we measured coronary artery calcium (CAC) using high-resolution, electrocardiographic, synchronized, computed tomography, for 314 HIV-infected men and women. Metabolic syndrome was defined by National Cholesterol Education Program/Adult Treatment Panel III criteria. We compared the c-IMT measurements and CAC scores of patients with metabolic syndrome with the scores of those without metabolic syndrome using a Wilcoxon test for continuous variables and a chi2 test for categorical variables. To examine the association between surrogate markers and metabolic syndrome, we used logistic regression analysis.

RESULTS

Participants with metabolic syndrome were more likely to have a common c-IMT measurement >0.8 mm than were those without metabolic syndrome (17% vs.7%; P=.009), but both groups were equally likely to have an internal c-IMT measurement >1.0 mm (20% vs. 13%; P=.15). Any positive CAC score was more likely to occur for participants with metabolic syndrome (80.3% vs. 46.7%; P<.0001). In a multivariate model adjusted for sex, age, ethnicity, and smoking status, participants with metabolic syndrome were more likely than those without metabolic syndrome to have an abnormal common c-IMT measurement (odds ratio [OR], 2.9; P=.020) and detectable CAC scores (OR, 4.9; P<.0001) but not a higher internal c-IMT measurement (OR, 1.6; P=.255).

CONCLUSION

Our study demonstrates that HIV-infected individuals with metabolic syndrome may be at increased risk for subclinical atherosclerosis and supports screening for metabolic syndrome among HIV-infected patients at risk for cardiovascular disease.

Both long-term HIV infection and highly active antiretroviral therapy are independent risk factors for early carotid atherosclerosis

OBJECTIVE

There is controversy over whether or not chronic HIV infection contributes to atherosclerosis. We investigated the relationship between HIV infection, antiretroviral medication and ultrasound evidence of early atherosclerosis in the context of vascular risk factors.

DESIGN

A case-control design with 292 HIV-positive subjects and 1168 age- and sex-matched controls.

METHODS

We assessed vascular risk factors, blood pressure, serum lipids and carotid intima media thickness (IMT) in cases and controls. With multivariate regression models, we investigated the effects of HIV status and antiretroviral medication on IMT.

RESULTS

The common carotid artery (CCA) IMT value was 5.70% (95% confidence interval [3.08-8.38%], p<0.0001) or 0.044 mm [0.021-0.066 mm] (p=0.0001) higher in HIV-positives, adjusted for multiple risk factors. In the carotid bifurcation (BIF), the IMT values were 24.4% [19.5-29.4%] or 0.250 mm [0.198-0.303 mm] higher in HIV patients (p<0.0001). An investigation of antiretroviral substances revealed higher CCA- and BIF-IMT values in patients receiving combination antiretroviral therapy (HAART).

CONCLUSIONS

HIV infection and HAART are independent risk factors for early carotid atherosclerosis. Assuming a risk ratio similar to that in large population-based cohorts, the observed IMT elevation suggests that vascular risk is 4-14% greater and the "vascular age" 4-5 years higher in HIV-positive subjects. The underlying mechanisms remain to be clarified.

Strategies for management and treatment of dyslipidemia in HIV/AIDS

With the improved survival of HIV-infected patients, there are increased concerns about the long-term effects of treatment, including protease inhibitor (PI)-related dyslipidemia. Some 50-70% of patients receiving combination antiretroviral therapy (ART) involving PIs develop lipid abnormalities consisting of elevated levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides that are well-known risk factors for cardiovascular disease. Treatment of HIV dyslipidemia should include lifestyle modifications such as a low-fat diet, increased exercise, reduced alcohol consumption and smoking cessation. In many patients, however, these changes alone will not correct lipid levels. In some patients, changing the PI component of ART to another PI or non-PI and/or lipid-lowering drugs has proven successful. Each approach is associated with advantages and limitations and the need to maintain viral suppression must be balanced with the need to treat abnormal lipid levels.

Substitution of nevirapine or efavirenz for protease inhibitor versus lipid-lowering therapy for the management of dyslipidaemia

OBJECTIVES

To evaluate simplified protease inhibitor (PI)-sparing antiretroviral treatment versus lipid-lowering therapy for the management of highly active antiretroviral therapy (HAART)-induced hyperlipidaemia.

DESIGN

Randomized, open-label clinical trial assessing the efficacy on hyperlipidaemia of a switching therapy from PI to non-nucleoside reverse transcriptase inhibitor (NNRTI) nevirapine or efavirenz versus a hypolipidaemic treatment (with pravastatin or bezafibrate) added to current, unchanged antiretroviral combination.

METHODS

All HIV-infected patients on their first HAART regimen, with stable immuno-virological features, naive to all NNRTIs, and with mixed hyperlipidaemia, were randomized to replace PI with nevirapine (arm A) or efavirenz (arm B), or to receive pravastatin (arm C) or bezafibrate (arm D) with unchanged HAART regimen, and were followed-up for 12 months.

RESULTS

One hundred and thirty patients were evaluated: 29 patients were randomized to arm A, 34 to arm B, 36 to arm C, and 31 to arm D. At the end of the 12-month follow-up, a reduction of 25.2, 9.4, 41.2 and 46.6% in mean triglyceridaemia versus respective baseline values was reported in groups A, B, C and D, respectively, with statistically significant difference between arms A-B and C-D (P < 0.01). Similar results were reported for total and low-density lipoprotein cholesterol levels. Viro-immunological efficacy and tolerability profile were comparable in all considered arms.

CONCLUSION

Pravastatin and bezafibrate proved significantly more effective in the management of HAART-related hyperlipidaemia than the switching therapy from PI to nevirapine or efavirenz.

Coronary artery calcium in HIV-infected men treated with highly active antiretroviral therapy

Calcium is a common component of an atherosclerotic plaque; therefore, the presence of coronary artery calcium (CAC) indicates atherosclerosis. This study investigated the difference in total CAC scores between HIV-infected patients treated with highly active antiretroviral therapy (HAART) and HIV-negative age-matched controls. HIV patients were 27 men treated with a protease inhibitor-containing HAART regimen for more than 1 year (M = 4.92 years, SD = 2.02), aged 30 to 60 years (M = 43.52 years, SD = 6.65), and not receiving lipid-lowering or hypoglycemic drugs. Controls were age-matched men randomly selected (three controls to one case, for a total of 81 controls) from our existing database of 25,250 men who self-referred for CAC screening (control database). Electron beam tomography was used to obtain CAC scores. The CAC scores were coded as above or below the age-specific (stratified in 5-year increments) 10th, 25th, 50th, 75th, or 90th percentile of our control database. Chi-square analyses for two independent samples indicated (1) a larger frequency of controls with CAC scores above the 10th (chi1= 8.32, P = .004) and 25th (chi1= 5.45, P = .02) percentiles than that of HIV patients, (2) no differences in CAC scores between groups above the 50th (chi = 0.85, P = .357) or 75th (chi = 0.46, P = .497) percentile, and (3) a larger frequency of HIV patients who were above the 90th percentile (chi = 4.5, P = .034). The strength of the relationship between group membership and scoring above the 90th percentile was significant (phi = 0.20, P = .034). These results tentatively suggest that there is an elevated level of subclinical atherosclerosis in HIV patients treated with HAART.

HIV-1 Tat increases the adhesion of monocytes and T-cells to the endothelium in vitro and in vivo: implications for AIDS-associated vasculopathy

HIV-1-infected patients exhibit severe damages of the aortic endothelium, develop angioproliferative lesions such as Kaposi's sarcoma (KS), and have an increased risk of cardiovascular diseases and atherosclerosis. An increased adhesion of leukocytes to the endothelium is a common pathogenic parameter of AIDS-associated vascular diseases. Here we show that the HIV-1 Tat protein, a regulatory protein of HIV-1 released by infected cells, and TNF-alpha, a cytokine increased in sera and tissues of HIV-1-infected patients, activate synergistically the adhesion of leukocytes to endothelial cells both in vitro and in vivo. This effect is selectively mediated by HIV-1 Tat, since HIV-1 Nef, another HIV-1 regulatory protein, and the HIV-1 envelope protein gp41, had no effect. In vitro adhesion assays with PBMC and quantitative cell type analysis of adherent cells by FACS demonstrated that HIV-1 Tat selectively activates the adhesion of T-cells and monocytes but not of B-cells. Intravital microscopic studies in mice confirmed the synergistic activity of HIV-1 Tat and TNF-alpha on leukocyte adhesion to the endothelium in vivo. These data indicate that HIV-1 Tat in cooperation with TNF-alpha may contribute to the vascular damage and cardiovascular diseases observed in AIDS patients but also to the prominent extravasation of T-cells and monocytes which is a key process in the formation and progression of KS lesions.

HIV Lipodystrophy Syndrome: A Primer

Treatment with highly active antiretroviral therapy (HAART) has been implicated in the development of anthropomorphic and metabolic abnormalities termed HIV lipodystrophy syndrome (or LDS). This primer offers a comprehensive overview of LDS including epidemiology, hypothesized etiologies, and clinical consequences. The evidence-based literature is reviewed for current treatment strategies including discontinuation of specific antiretrovirals, pharmacological management of dyslipidemia and insulin resistance, exercise training, facial augmentation, liposuction, and hormonal therapy. Patient education, counseling, and adherence are discussed.

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.

Expression of adipogenic transcription factors, peroxisome proliferator-activated receptor gamma co-activator 1, IL-6 and CD45 in subcutaneous adipose tissue in lipodystrophy associated with highly active antiretroviral therapy

OBJECTIVE

To determine the expressions of multiple genes in the subcutaneous adipose tissue of HIV-positive, highly active antiretroviral therapy (HAART)-treated patients with and without lipodystrophy.

DESIGN AND METHODS

Real-time polymerase chain reaction was used to measure gene expressions in this cross-sectional study.

RESULTS

The messenger RNA concentrations of adipose transcription factors (peroxisome proliferator-activated receptor (PPAR) gamma and delta and sterol regulatory element binding protein 1c) were all significantly lower in the lipodystrophic than the non-lipodystrophic group. The mRNA concentration of PPAR-gamma co-activator 1 (PGC-1), which regulates mitochondrial biogenesis, was lower in the lipodystrophic than the non-lipodystrophic group. The mRNA expression of lipoprotein lipase, acyl coenzyme A synthase and glucose transport protein 4 were significantly lower in the lipodystrophic than the non-lipodystrophic group, but the mRNA concentrations of fatty acid transport and binding proteins were similar in both groups. The mRNA concentrations of IL-6 and CD45 (a common leukocyte marker) were significantly higher in the lipodystrophic than the non-lipodystrophic group.

CONCLUSION

Multiple alterations characterize gene expression in the subcutaneous adipose tissue of patients with HAART-associated lipodystrophy compared with HIV-positive, HAART-treated patients without lipodystrophy. The low expression of transcription factors inhibits adipocyte differentiation. The low expression of PGC-1 may contribute to mitochondrial defects. In addition, IL-6 and CD45 expressions are increased, the latter implying an excessive number of cells of leukocyte origin in lipodystrophic adipose tissue. Mitochondrial injury and an excess of proinflammatory cytokines may lead to increased apoptosis. All these changes may contribute to the loss of subcutaneous fat in HAART-associated lipodystrophy.

Incidence of myocardial infarction in randomized clinical trials of protease inhibitor-based antiretroviral therapy: an analysis of four different protease inhibitors

Protease inhibitor (PI) therapy for patients infected with the human immunodeficiency virus has been associated with lipid disorders and insulin resistance. We compared the incidence of myocardial infarction (MI) among participants receiving treatment with PIs with or without nucleoside reverse transcriptase inhibitors (nRTIs) to nRTI therapy alone in 30 phase II/III double-blind, randomized studies conducted before 1999 for the first 4 PI drugs. In most trials included in this analysis, participants could receive combination therapy with a PI plus nRTIs in open-label extensions after the blinded phase concluded. Person-years (PY) of follow-up were calculated from treatment initiation to the diagnosis of MI, or to the end of the randomized phases for nRTI-only therapy or to the conclusion of the studies for PI-containing regimens. Separate analyses were conducted for the randomized and the randomized-plus-extension phases. Among 10,986 participants, 7951 (72%) received PI drugs at some point for an average duration of 12 months. There were 10 MIs (1.31/1000 PY) in the randomized phases and 19 MIs (1.63/1000 PY) in the randomized-plus-extension phases. The overall stratified relative risk of MI for PI-containing (1.82 MI/1000 PY) versus nRTI-only (1.05 MI/1000 PY) regimens of 1.69 was not significantly increased (95% confidence interval [CI], 0.54 to 7.48). The absolute difference in MI risk was +0.77 (95% CI, -0.71 to +2.26) MIs/1000 PY. Compared with NRTI-only therapy, patients receiving PI-containing regimens for an average of 1 year did not have significantly more MIs, but the upper bound of the 95% CI indicates there may be up to 2.3 additional MIs per 1000 PY. Although studies with a longer duration of PI therapy are in progress to assess whether a later increase in MI incidence occurs, our analysis did not demonstrate a dramatic increase in MI risk during the first year of PI therapy.

Decrease in LDL size in HIV-positive adults before and after lopinavir/ritonavir-containing regimen: an index of atherogenicity?

BACKGROUND

Hypertriglyceridemia (HTG) is frequently observed during highly active antiretroviral therapy (HAART) including protease inhibitor. Apolipoprotein (apo) CIII could be involved in this HTG by inhibition of triglyceride (TG) hydrolysis, which leads to the occurrence of small dense low density lipoprotein (sdLDL), a recognized cardiovascular risk factor.

OBJECTIVE

To characterize the influence of lopinavir/ritonavir-containing regimen on lipoprotein profile.

DESIGN AND METHODS

24 antiretroviral-experienced HIV infected adults (including 14 patients in therapeutic interruption of at least 2 months) and 14 HIV uninfected healthy controls were enrolled. Serum lipid parameters (total cholesterol (TC), HDL-C, LDL-C, TG, apoA1, apoB, apoCIII), lipoprotein composition and LDL size were determined before initiation of lopinavir/ritonavir-containing regimen, and at 1 and 3 months thereafter.

RESULTS

At baseline an atherogenic lipid profile was evidenced, characterized by a moderate HTG associated to a smaller mean LDL size (25.16 vs 25.93 nm, P<0.001), an enrichment in TG of LDL (11.4 vs 6.0%, P<0.01) and a high prevalence of sdLDL (75 vs 7%, P<0.01) when compared to controls. After 1 month of lopinavir/ritonavir-containing regimen, a significant reduction of LDL size (24.81 vs 25.16 nm, P<0.05) and a significant increase in cholesterol total (5.53 vs 4.49 mmol/l, P<0.001), in TG (4.20 vs 2.01 mmol/l, P<0.001), in apoA1 (1.28 vs 1.11 g/l, P<0.001), in apoB (1.08 vs 0.94 g/l, P<0.01), in apoCIII (0.16 vs 0.10 g/l, P<0.001), in TG percentage in LDL (14.4 vs 11.4, P<0.05) and in TG percentage in HDL (10.2 vs 8.3, P<0.05) were observed.

CONCLUSIONS

Advanced stage of HIV infection is associated with an atherogenic lipid profile including a high prevalence of sdLDL. Lopinavir/ritonavir-containing regimen accentuates the reduction of LDL size. Since fibrates decrease TG and increase LDL size, they appear as a logical option to manage HAART-induced HTG.