Effects of HIV disease on lipid, glucose and insulin levels: results from a large antiretroviral-naive cohort

The macrophage: the intersection between HIV infection and atherosclerosis

HIV-infected individuals are at increased risk of coronary artery disease (CAD) with underlying mechanisms including chronic immune activation and inflammation secondary to HIV-induced microbial translocation and low-grade endotoxemia; direct effects of HIV and viral proteins on macrophage cholesterol metabolism; and dyslipidemia related to HIV infection and specific antiretroviral therapies. Monocytes are the precursors of the lipid-laden foam cells within the atherosclerotic plaque and produce high levels of proinflammatory cytokines such as IL-6. The minor CD14+/CD16+ "proinflammatory" monocyte subpopulation is preferentially susceptible to HIV infection and may play a critical role in the pathogenesis of HIV-related CAD. In this review, the central role of monocytes/macrophages in HIV-related CAD and the importance of inflammation and cholesterol metabolism are discussed.

Factors associated with serum retinol, alpha-tocopherol, carotenoids, and selenium in Hispanics with problems of HIV, chronic hepatitis C, and drug use

The effects of hepatitis and drug use on nutritional problems in HIV infection have rarely been examined despite the importance of drug use in the global HIV pandemic. We examined the effects of HIV, hepatitis C, and drug use on serum micronutrients in 300 US Hispanic adults. Chronic hepatitis C infection was associated with lower serum retinol (-8.2 microg/dl, P < 0.0001), alpha-tocopherol (-0.10 ln microg/dl, P = 0.024), and carotenoids (-19.8 microg/dl, P < 0.0001). HIV infection was associated with lower selenium (-6.1 microg/l, P = 0.028). Elevated triglycerides in HIV infection were associated with higher serum retinol and alpha-tocopherol. Drug use was not independently associated with micronutrient alterations. We conclude that hepatitis C is an important determinant of low serum micronutrients, and should be considered in any nutritional assessment of HIV infected populations. As the safety of micronutrient supplementation is not established, policy for appropriate HIV clinical care should distinguish between populations with and without hepatitis coinfection.

Association between human adenovirus-36 and lipid disorders in Korean schoolchildren

BACKGROUND

Although the human adenovirus-36 (Ad-36) has been associated with obesity and related lipid disorders in the United States, this association has yet to be identified in other countries. Therefore, we tried to determine whether Ad-36 is associated with obesity or lipid disorders in Korean schoolchildren.

METHOD

A total of 318 Korean schoolchildren aged 6-15 years, who participated in the Ewha Womans University Obesity Research Study, were selected for a community-based cohort study. Non-obese and obese were defined as body mass index (BMI) <85th and > or = 95th percentiles of the Korean reference BMI-for-age curves, respectively, according to International Obesity Task Force definitions. The cutoff points for lipid disorders were modified from the age-modified standards of the National Cholesterol Education Program (NCEP)-Adult Treatment Panel (ATP) III metabolic syndrome criteria. The Ad-36 antibody was measured using a serum neutralization assay.

RESULTS

More obese participants than non-obese participants tested positive for the Ad-36 antibody (28.57 vs 13.56%, respectively; P = 0.0174). Within the obese group, the participants who tested positive for the Ad-36 antibody had higher levels of triglycerides (TG) and total cholesterol than those who tested negative for the Ad-36 antibody (P<0.001). However, these associations were not present in the non-obese group. The unadjusted odds ratio (OR) for Ad-36 antibody positivity was greater in obese participants than non-obese participants (OR = 2.550, 95% confidence interval (CI): 1.154-5.633). However, this OR seemed to be nonsignificant when age, sex and lipid variables were included in the analysis (OR = 1.752, 95% CI: 0.763-4.020). The unadjusted OR for the elevated TG was significantly higher in participants who were Ad-36 antibody-positive than those who were Ad-36 antibody-negative (OR = 2.511, 95% CI: 1.448-4.353). This trend remained constant even after adjustment for age, sex and obesity (OR = 2.328, 95% CI: 1.296-4.181).

CONCLUSION

Ad-36 seems to be strongly associated with lipid disorders in Korean schoolchildren regardless of obesity.

A longitudinal study of the changes in body fat and metabolic parameters in a South African population of HIV-positive patients receiving an antiretroviral therapeutic regimen containing stavudine

The aim of this study was to determine the patterns of change in body fat and metabolic parameters in a South African cohort on a first line ART regimen containing stavudine. Fasting lipogram, blood glucose and insulin levels, CD4 cell count, viral load, BMI, waist-to-hip ratio (WHR), and skinfold thickness at the triceps, scapula, and iliac crest were measured before starting ART in 42 (27 female) subjects. Repeat measurements were performed at four monthly intervals for 2 years. Lipodystrophy was diagnosed using patient perception and assessment by a physician. At baseline, subjects who went on to develop lipodystrophy (LD group) were fatter and had higher skinfold thickness at all three sites and higher insulin levels than subjects who never developed lipodystrophy (NLD group). The WHR increased to a greater extent while hip circumference and tricep skinfolds fell more significantly in the LD than NLD group. Triglyceride and cholesterol levels increased significantly in both groups while lactate and glucose levels increased more and insulin levels increased less in the LD than the NLD group. Neither viral load nor CD4 count differed between the groups during the study. Viral load correlated positively with insulin levels at baseline. Thus, lipodystrophy in the South African population is characterized by a higher BMI before initiation of ART and lipoatrophy of the arms and hips, lipohypertrophy of the waist, and increased lactate production. When compared to the NLD group, the LD subjects display attenuated insulin secretory output in response to a higher weight gain.

The individual and combined influence of HIV and hepatitis C virus on dyslipidaemia in a high-risk Hispanic population

OBJECTIVES

To assess the effects of chronic hepatitis C (HCV) and HIV infection on dyslipidaemia in a Hispanic population at high risk of insulin resistance.

METHODS

We compared serum lipids and C-reactive protein (CRP) in 257 Hispanic adults including 47 HIV- mono-infected, 43 HCV-mono-infected and 59 HIV/HCV-co-infected individuals as well as 108 healthy controls. We also assessed the effect of HCV on lipid alterations associated with antiretroviral therapy (ART), and the impact of HCV and HIV on the associations among insulin resistance, triglycerides and cholesterol.

RESULTS

HCV infection was associated with lower total and low-density lipoprotein (LDL) cholesterol, but not high-density lipoprotein (HDL) cholesterol or triglycerides compared with healthy controls. HIV infection was associated with higher triglycerides and lower HDL, but not total or LDL cholesterol. HCV mitigated the elevation of triglycerides associated with ART. In healthy Hispanic adults, insulin resistance was significantly correlated with higher triglycerides, CRP and lower HDL. HIV infection nullified the association of insulin resistance with triglycerides and HDL, and the association of triglycerides with LDL. HCV infection nullified the association of insulin resistance with triglycerides, HDL and CRP.

CONCLUSIONS

HCV co-infection alters the profile of HIV-associated dyslipidaemia. The clinical significance of these findings for cardiovascular complications in HIV merits further study.

Prevalence and pathogenesis of diabetes mellitus in HIV-1 infection treated with combined antiretroviral therapy

Combined antiretroviral therapy (cART) in the treatment of HIV-1 infection confers significant survival benefit and, by immunoreconstitution, has altered the natural history of this life-threatening disease. Metabolic complications of cART include hyperlipidemia, insulin resistance, and lipodystrophy, with resultant increases in risk for type 2 diabetes and cardiovascular disease. These diseases will present new challenges in the management of HIV infection. This article reviews the prevalence of diabetes mellitus and its antecedents in HIV-infected patients treated with cART. It also reviews the current understanding of mechanisms involved in the pathogenesis of type 2 diabetes in cART considering insulin resistance and insulin secretion, both requisites for the development of type 2 diabetes mellitus.

Improvement in lipid profiles over 6 years of follow-up in adults with AIDS and immune reconstitution

OBJECTIVES

The aim of the study was to evaluate long-term changes in lipids and to assess other coronary heart disease (CHD) risk factors in highly experienced AIDS patients with immune reconstitution, and to examine their association with antiretroviral therapy (ART).

METHODS

We evaluated 433 AIDS patients with prior severe immunosuppression and ART-based immune reconstitution, followed in a multicentre prospective observational study between 2000 and 2006. We estimated the prevalence at entry of hypercholesterolaemia and metabolic syndrome, and 10-year CHD risks. Trends in total cholesterol (TC), triglycerides (TG) and high-density lipoprotein (HDL) cholesterol were evaluated over time, and use of specific ART drugs at each study visit was assessed using mixed effect models, adjusting for CHD risk factors and use of lipid-lowering agents.

RESULTS

At entry to observational follow-up, 28% of the 433 subjects had hypercholesterolaemia and 15% had a predicted 10-year CHD risk above 20%. Average TC and fasting TG levels declined over the follow-up period (median=5.8 years), and these declines were associated with increased use of physician-prescribed lipid-lowering agents and changes in ART regimens. After adjustment for CHD risk factors, TC and TG levels were significantly higher for those on ritonavir-boosted protease inhibitors and those on nonnucleoside reverse transcriptase inhibitors (NNRTIs), particularly efavirenz, than for other patients.

CONCLUSIONS

Abnormalities in serum lipids were common at baseline but became less so over time, and this improvement was associated with increased use of lipid-lowering agents and selection of ART agents with less deleterious effects on lipids.

Cardiovascular complications in HIV management: past, present, and future

Highly active antiretroviral therapy (HAART) has significantly improved the prognosis for many individuals with HIV infection. Consequently, HIV infection has become a chronic and manageable disease. The focus on long-term management of patients with HIV infection has broadened to include comorbid conditions, most notably cardiovascular disease. Patients with HIV infection share many cardiovascular risk factors with the general population, and HIV infection itself may increase cardiovascular risk. Changes in lipid profiles associated with increased cardiovascular risk that have been observed with some HAART regimens have been a cause for concern among clinicians who treat HIV-infected patients. However, the lipid effects of HAART seem to depend on the type and duration of regimens employed. They can be managed effectively according to current guidelines that recommend lifestyle changes (eg, improved diet, increased exercise, smoking cessation) and pharmacologic therapy described in established treatment paradigms for patients on antiretroviral therapy and similar to measures currently used by the general population. A review of the clinical data indicates that the virologic and immunologic benefits of HAART clearly outweigh any metabolic effects observed in some patients over time and that preexisting, established cardiovascular risk factors contribute significantly to the potential development of cardiovascular events. These benefits of antiretroviral therapy have been demonstrated in studies comparing the superior efficacy of continuous vs. intermittent HAART.

Racial differences in changes of metabolic parameters and body composition in antiretroviral therapy-naive persons initiating antiretroviral therapy

OBJECTIVE

To assess by race/ethnicity long-term changes in metabolic parameters and body composition among treatment-naive persons initiating antiretroviral therapy (ART).

METHODS

We compared changes in 398 participants (African American n = 243, Latino n = 43, white n = 112) initiating ART. At baseline, 1-month (metabolic parameters only) and 4-month follow-up intervals (anthropometric measurements) were performed and fasting metabolic parameters measured. Rates of change over time and overall mean changes from baseline were compared.

RESULTS

Latinos had the greatest increase in glucose and insulin resistance and greatest loss of mid-arm and mid-thigh subcutaneous tissue areas. On average, mid-arm and mid-thigh nonsubcutaneous tissue areas increased in all races. Waist subcutaneous tissue area decreased only for Latinos. Visceral tissue area increased the most for Latinos and whites. For all groups, the initial increase in high-density lipoprotein cholesterol was sustained. The initial increase in low-density lipoprotein cholesterol was followed by a gradual decline in all groups. Triglycerides increased for all groups; the increase being the least for African Americans.

CONCLUSIONS

In this prospective long-term evaluation, changes in metabolic parameters and body composition varied across race groups. Latinos experienced the most unfavorable changes. Such changes should be monitored over time as the identified differences may impact ART selection.

Relationship of postprandial nonesterified fatty acids, adipokines, and insulin across gender in human immunodeficiency virus-positive patients undergoing highly active antiretroviral therapy

BACKGROUND

Metabolic derangements are common in human immunodeficiency virus (HIV)-positive subjects undergoing antiretroviral therapy, but little is known about postprandial conditions.

METHODS

We investigated the relationship between leptin, adiponectin, nonesterified fatty acids (NEFA), and insulin in response to a day-long meal pattern and evaluated gender differences in HIV-positive men (n = 12) and women (n = 13) undergoing highly active antiretroviral therapy (HAART).

RESULTS

For both men and women, a significant decrease in postprandial NEFA levels was observed following breakfast (0.53 vs. 0.22 mmol/L, P < 0.001, baseline and at 3 hours, respectively), whereas day-long postprandial leptin and adiponectin levels showed small nonsignificant oscillations. In contrast to NEFA and adiponectin, postprandial leptin levels were significantly higher among women compared to men (P < 0.05). Postprandial NEFA levels correlated positively with fasting insulin levels (r(2) = 0.25, P = 0.016), and the postbreakfast decrease in NEFA levels correlated significantly with the postbreakfast increase in insulin levels (r(2) = 0.17, P = 0.038). No significant association between postprandial adipokines and insulin was observed.

CONCLUSIONS

In HAART-treated, HIV-infected men and women, levels of NEFA, but not adipokines, showed significant postprandial variation. Furthermore, food intake resulted in significant NEFA suppression in proportion to the food-stimulated insulin increase.

O-linked N-acetylglucosaminylation of Sp1 inhibits the human immunodeficiency virus type 1 promoter

Human immunodeficiency virus type 1 (HIV-1) gene expression and replication are regulated by the promoter/enhancer located in the U3 region of the proviral 5' long terminal repeat (LTR). The binding of cellular transcription factors to specific regulatory sites in the 5' LTR is a key event in the replication cycle of HIV-1. Since transcriptional activity is regulated by the posttranslational modification of transcription factors with the monosaccharide O-linked N-acetyl-D-glucosamine (O-GlcNAc), we evaluated whether increased O-GlcNAcylation affects HIV-1 transcription. In the present study we demonstrate that treatment of HIV-1-infected lymphocytes with the O-GlcNAcylation-enhancing agent glucosamine (GlcN) repressed viral transcription in a dose-dependent manner. Overexpression of O-GlcNAc transferase (OGT), the sole known enzyme catalyzing the addition of O-GlcNAc to proteins, specifically inhibited the activity of the HIV-1 LTR promoter in different T-cell lines and in primary CD4(+) T lymphocytes. Inhibition of HIV-1 LTR activity in infected T cells was most efficient (>95%) when OGT was recombinantly overexpressed prior to infection. O-GlcNAcylation of the transcription factor Sp1 and the presence of Sp1-binding sites in the LTR were found to be crucial for this inhibitory effect. From this study, we conclude that O-GlcNAcylation of Sp1 inhibits the activity of the HIV-1 LTR promoter. Modulation of Sp1 O-GlcNAcylation may play a role in the regulation of HIV-1 latency and activation and links viral replication to the glucose metabolism of the host cell. Hence, the establishment of a metabolic treatment might supplement the repertoire of antiretroviral therapies against AIDS.

Predictors of insulin resistance among Hispanic adults infected with or at risk of infection with the human immunodeficiency virus and hepatitis C virus

Both the human immunodeficiency (HIV) and hepatitis C (HCV) viruses have been associated with insulin resistance (IR). However, our understanding of the prevalence of IR, the underlying mechanisms and predisposing factors is limited, particularly among minority populations. We conducted a study of 333 Hispanic adults including: 76 HIV monoinfected, 62 HCV monoinfected, 97 HIV/HCV co-infected and 98 uninfected controls with a specific focus on HCV infection and liver injury as possible predictors of IR. IR was measured using the Quantitative Insulin Sensitivity Check Index (QUICKI). The majority (55-69%) of participants in all groups had QUICKI values <0.350. Body mass index was associated with IR in all groups. Triglycerides were associated with IR in the uninfected control group only (-1.83, SE = 0.58, P = 0.0022). HCV was associated with IR in participants infected with HIV (-0.012, SE = 0.0046, P = 0.010). Liver injury, as measured by score to assess liver injury (FIB-4) score, was significantly associated with IR independently of HCV infection (-0.0035, SE = 0.0016, P = 0.027). In the HIV/HCV co-infected group, treatment with nucleoside reverse-transcriptase (RT) inhibitors plus non-nucleoside RT inhibitors (-0.021, SE = 0.080, P = 0.048), but not protease inhibitors (-0.000042, SE = 0.0082, P = 0.96) was associated with IR. HCV infection and antiretroviral agents, including nucleoside RT inhibitor plus non-nucleoside RT inhibitor treatment are contributors to IR in HIV infection. Liver injury, as measured by the FIB-4 score, is a predictor of IR independently of HCV infection.

Metformin increases HDL3-cholesterol and decreases subcutaneous truncal fat in nondiabetic patients with HIV-associated lipodystrophy

The purpose of this study was to assess metformin effects on high-density lipoprotein (HDL) composition of patients with HIV-associated lipodystrophy (LDHIV). Twenty-four adult outpatients were enrolled to receive metformin (1700 mg/d) during 6 months, but 2 were lost to follow-up and 6 stopped the drug due to adverse events (gastrointestinal in 5, and excessive weight loss in 1). From the 16 subjects who completed the study, 69% were female. At baseline, 3 and 6 months, we assessed: weight, waist and hip circumferences, blood pressure, fasting glucose and insulin, homeostasis model assessment of insulin resistance (HOMA2-IR), lipids, and HDL subfractions by microultracentrifugation. At 0 and 6 months, body fat distribution was assessed by computed tomography (CT) scan (L4 and middle femur). Metformin use was associated with reduction of mean weight (-2.4Kg at 6 months; p < 0.001), body mass index, waist, waist-to-hip ratio and a marked decrease in blood pressure (p < 0.001). Subcutaneous (p = 0.01) and total abdominal fat (p = 0.002) were reduced, but no change was found in visceral or thigh fat. No difference was detected on plasma glucose, insulin, HOMA2-IR, cholesterol or triglycerides, except for an increase in HDL3-cholesterol (from 21 mg/dL to 24 mg/dL, p = 0.002) and a reduction of nascent HDL (the fraction of plasma HDL-cholesterol not associated to subfractions HDL2 or HDL3) (p = 0.008). Adverse effects were very common, but most were gastrointestinal and mild. Thus, metformin use in LDHIV increases HDL3-cholesterol (probably due to improved maturation of HDL) and decreases blood pressure, weight, waist, and subcutaneous truncal fat, making this an attractive option for preventing cardiovascular disease in this population.

Antiretroviral therapy is associated with an atherogenic lipoprotein phenotype among HIV-1-infected men in the Multicenter AIDS Cohort Study

BACKGROUND

Alterations in serum lipids and an increased risk of myocardial infarction have been associated with HIV-1 infection and its treatment.

METHODS

Lipoprotein subclasses were measured by nuclear magnetic resonance spectroscopy in frozen plasma samples from participants in the Multicenter AIDS Cohort Study. The effects of HIV-1 infection, antiretroviral therapy, and other factors on median particle concentrations were examined using quantile regression.

RESULTS

Fasted samples were tested from 1082 men, including 609 HIV-seronegative and 473 HIV-1-infected men. Compared with HIV-seronegative men, HIV-1-infected men on antiretroviral therapy had an atherogenic phenotype with higher numbers of very low density lipoprotein and small low-density lipoprotein particles and lower numbers of high-density lipoprotein and large low-density lipoprotein particles. HIV-infected, antiretroviral-naive men had significantly lower high-density lipoprotein and small low-density lipoprotein particle concentrations compared with the HIV-seronegative men. Among men on antiretroviral therapy, the atherogenic phenotype was most pronounced in men with a good clinical status.

CONCLUSION

Use of antiretroviral therapy in HIV-1-infected men was associated with an "atherogenic lipoprotein phenotype."

Disorders of glucose metabolism in human immunodeficiency virus-infected patients

Over the past 10 years, the development of highly active antiretroviral therapy (HAART) has dramatically improved morbidity and mortality in human immunodeficiency virus (HIV)-infected patients. Since the introduction of HAART however, unexpected metabolic abnormalities, including lipodystrophy, dyslipidaemia and dysregulation of glucose metabolism, are reported with increasing frequency in HIV-infected persons. Such metabolic disorders, if not treated, may be associated with an increased risk of cardiovascular disease in HIV-infected patients. In this paper, the prevalence, mechanisms and therapeutic strategies for the disorders of glucose metabolism in the context of HIV-infection are discussed.

High-density lipoprotein cholesterol in HIV-infected patients: evidence for an association with HIV-1 viral load, antiretroviral therapy status, and regimen composition

Low high-density lipoprotein-cholesterol (HDL-C) levels have been associated with cardiovascular risk in non-HIV populations. Limited information exists on the prevalence of low HDL-C in HIV- infected patients and related factors remain largely unknown. The aims of this study were to estimate the prevalence and characteristics of low HDL-C levels in HIV-infected patients. A cross-sectional study was performed in consecutive HIV-infected patients cared for in an outpatient HIV clinic on the Mediterranean coast of Spain during a 2-month period (September 15, 2003 to November 15, 2003). HDL-C levels below 40 mg/dL were considered low. We analyzed data from 219 patients, 167 of whom were on antiretroviral therapy. The majority (45.20 %) were on non-nucleoside reverse transcriptase inhibitors (NNRTI); 22.83 % were on treatment with protease inhibitors. The prevalence of low HDL-C levels was 44.74 % (98 of 219 patients). In multivariate analysis, hypertriglyceridemia (triglycerides >150 mg/dL; odds ratio [OR], 5.65; 95% confidence interval [CI], 2.85-11.23; p = 0.0001), HIV-1 RNA viral load greater than 50 copies per milliliter (OR, 3.15; 95% CI, 1.63-6.109; p = 0.001) and antiretroviral therapy with regimens other than NNRTIs-based regimens (OR, 2.17; 95% CI, 1.12-4.16; p = 0.021) were associated with low HDL-C levels. These data indicate that prevalence of low HDL-C among HIV-infected patients from this cohort was very high. Low HDL-C was related to triglyceride levels, HIV-1 RNA viral load and antiretroviral therapy composition. Undetectable viral load and treatment with NNRTIs are protective factors, whereas hypertriglyceridemia is directly associated with low HDL-C levels.

Lipid and glucose alterations in HIV-infected children beginning or changing antiretroviral therapy

OBJECTIVE

The objective of this study was to describe lipid profiles and glucose homeostasis in HIV-positive children after initiating or changing antiretroviral therapy and their associations with viral, immune, antiretroviral therapy, and growth factor parameters.

METHODS

Ninety-seven prepubertal HIV-positive children aged 1 month to <13 years were observed for 48 weeks after beginning or changing antiretroviral therapy. Fasting lipid panels, serum glucose, insulin, insulin-like growth factor-1 and binding proteins-1 and -3, plasma viral load, and CD4% were measured. Each child was matched on age, gender, and race/ethnicity to children from the National Health and Nutrition Examination Survey, used to give z scores for each child's lipid values. Multivariate regression was used to evaluate the association of changes in z scores over 48 weeks with suppression of HIV-1 RNA, change in CD4% and growth factors, and antiretroviral therapy, adjusted for entry z score, CD4%, log(10) HIV-1 RNA, Centers for Disease Control and Prevention category, and total fat and cholesterol dietary intake.

RESULTS

Lipid, apolipoprotein, and insulin levels all increased significantly by 48 weeks. Multivariate analysis of changes demonstrated that increased HDL and decreased total-HDL cholesterol ratio were associated with CD4% increase and with insulin-like growth factor-1, which increased to normal (versus remained stable or became low) over 48 weeks. Total cholesterol levels increased among children who achieved HIV-1 RNA of <400 copies per mL. Antiretroviral therapy regimens that included both a protease inhibitor and a non-nucleoside reverse transcriptase inhibitor were associated with greater increases in total-HDL cholesterol ratio than regimens that contained a protease inhibitor or a non-nucleoside reverse transcriptase inhibitor but not both.

CONCLUSIONS

In these HIV-positive children with predominantly mild-to-moderate disease, initiation or change in antiretroviral therapy was associated with significant increases in multiple lipid measures and insulin resistance. Favorable lipid changes were associated with CD4% increases, suggesting a protective effect of immune reconstitution on atherosclerosis, and with increased insulin-like growth factor-1 levels, supporting the theory that reduced growth hormone resistance may be a mechanism by which lipid profiles are improved. Finally, antiretroviral therapy regimens that contain both a non-nucleoside reverse transcriptase inhibitor and a protease inhibitor are associated with worse lipid profiles than regimens that contain 1 but not both of these drug classes.

The associations of regional adipose tissue with lipid and lipoprotein levels in HIV-infected men

BACKGROUND

HIV infection and antiretroviral therapy are associated with dyslipidemia, but the association between regional adipose tissue depots and lipid levels is not defined.

METHODS

The association of magnetic resonance imaging-measured visceral adipose tissue (VAT) and regional subcutaneous adipose tissue (SAT) volume with fasting lipid parameters was analyzed by multivariable linear regression in 737 HIV-infected and 145 control men from the study of Fat Redistribution and Metabolic Change in HIV Infection.

RESULTS

HIV-infected men had higher median triglycerides (170 mg/dL vs. 107 mg/dL; P < 0.0001), lower high-density lipoprotein cholesterol (HDL-C; 38 mg/dL vs. 46 mg/dL; P < 0.0001), and lower low-density lipoprotein cholesterol (LDL-C; 105 mg/dL vs. 125 mg/dL; P < 0.0001) than controls. After adjustment, greater VAT was associated with higher triglycerides and lower HDL-C in HIV-infected and control men, whereas greater leg SAT was associated with lower triglycerides in HIV-infected men with a similar trend in controls. More upper trunk SAT was associated with higher LDL-C and lower HDL-C in controls, whereas more lower trunk SAT was associated with higher triglycerides in controls. After adjustment, HIV infection remained strongly associated (P < 0.0001) with higher triglycerides (+76%, 95% confidence interval [CI]: 53 to 103), lower LDL-C (-19%, 95% CI: -25 to -12), and lower HDL-C (-18%, 95% CI: -22 to -12).

CONCLUSIONS

HIV-infected men are more likely than controls to have higher triglycerides and lower HDL-C, which promote atherosclerosis, but also lower LDL-C. Less leg SAT and more VAT are important factors associated with high triglycerides and low HDL-C in HIV-infected men. The reduced leg SAT in HIV-infected men with lipoatrophy places them at increased risk for proatherogenic dyslipidemia.

Simple anthropometric measures correlate with metabolic risk indicators as strongly as magnetic resonance imaging-measured adipose tissue depots in both HIV-infected and control subjects

BACKGROUND

Studies in persons without HIV infection have compared percentage body fat (%BF) and waist circumference as markers of risk for the complications of excess adiposity, but only limited study has been conducted in HIV-infected subjects.

OBJECTIVE

We compared anthropometric and magnetic resonance imaging (MRI)-based adiposity measures as correlates of metabolic complications of adiposity in HIV-infected and control subjects.

DESIGN

The study was a cross-sectional analysis of 666 HIV-positive and 242 control subjects in the Fat Redistribution and Metabolic Change in HIV Infection (FRAM) study assessing body mass index (BMI), waist (WC) and hip (HC) circumferences, waist-to-hip ratio (WHR), %BF, and MRI-measured regional adipose tissue. Study outcomes were 3 metabolic risk variables [homeostatic model assessment (HOMA), triglycerides, and HDL cholesterol]. Analyses were stratified by sex and HIV status and adjusted for demographic, lifestyle, and HIV-related factors.

RESULTS

In HIV-infected and control subjects, univariate associations with HOMA, triglycerides, and HDL were strongest for WC, MRI-measured visceral adipose tissue, and WHR; in all cases, differences in correlation between the strongest measures for each outcome were small (r

CONCLUSION

Relations of simple anthropometric measures with HOMA, triglycerides, and HDL cholesterol are approximately as strong as MRI-measured whole-body adipose tissue depots in both HIV-infected and control subjects.

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Key Words Collapse

MESH Headings

• Adipose Tissue/anatomy & histology
• Adult
• Anthropometry/methods
• Body Mass Index
• Body Size
• Cross-Sectional Studies
• Female
• HIV Infections/complications
• HIV Infections/epidemiology
• Humans
• Magnetic Resonance Imaging/methods
• Male
• Middle Aged
• Patient Selection
• Predictive Value of Tests
• Reference Values
• Risk Assessment
• Waist-Hip Ratio

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Grants

• HL74814 NHLBI NIH HHS
• R01 HL074814-06 NHLBI NIH HHS
• R01 DK057508-03S1 NIDDK NIH HHS
• M01 RR000054 NCRR NIH HHS
• RR00052 NCRR NIH HHS
• RR0636 NCRR NIH HHS
• M01 RR000083 NCRR NIH HHS
• RR00054 NCRR NIH HHS
• R01 DK057508-03 NIDDK NIH HHS
• R01 DK057508-01S1 NIDDK NIH HHS
• RR00865 NCRR NIH HHS
• R01-DK57508 NIDDK NIH HHS
• R01 DK057508 NIDDK NIH HHS
• R01 HL074814-07 NHLBI NIH HHS
• R01 DK057508-01 NIDDK NIH HHS
• RR00083 NCRR NIH HHS
• M01 RR000865 NCRR NIH HHS
• M01 RR000036 NCRR NIH HHS
• HL 53359 NHLBI NIH HHS
• R01 HL074814-04 NHLBI NIH HHS
• RR00051 NCRR NIH HHS
• R01 DK057508-03S2 NIDDK NIH HHS
• M01 RR000052 NCRR NIH HHS
• R01 HL074814-05 NHLBI NIH HHS
• M01 RR000051 NCRR NIH HHS
• M01-RR00036 NCRR NIH HHS
• R01 HL074814 NHLBI NIH HHS
• R01 DK057508-02 NIDDK NIH HHS

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Affiliation(s)

Rebecca Scherzer Northern California Institute for Research and Education, San Francisco, CA, USA
Wei Shen
Peter Bacchetti
Donald Kotler
Cora E Lewis
Michael G Shlipak
Steven B Heymsfield
Carl Grunfeld

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Metabolic abnormalities and overweight in HIV/AIDS persons-treated with antiretroviral therapy

OBJECTIVE: To describe the proportion of overweight among patients with human immunodeficiency virus/Acquired Immune Deficiency Syndrome and correlate overweight and highly active antiretroviral therapy with metabolic complications. METHODS: A cross-sectional study was conducted among human immunodeficiency virus/Acquired Immune Deficiency Syndrome outpatients undergoing nutritional therapy from 2000 to 2006 in a University Health Center. The sample consisted of 393 human immunodeficiency virus/Acquired Immune Deficiency Syndrome patients. Nutritional and medical records were used as a source of data on personal, clinical and biochemical information. Data analysis included descriptive statistics and the Chi-square test. RESULTS: Sixty-nine percent of the patients were males aging from 26 to 49 years. Overweight and obesity were identified in 49% of this population. The most important metabolic complications were low levels of high-density lipoprotein (70%) and high levels of triglycerides (48%) and cholesterol (40%). Higher body mass index was associated with higher lipid levels and more evidence of insulin resistance. CONCLUSION: This study demonstrated an important proportion of overweight and obesity among human immunodeficiency virus/Acquired Immune Deficiency Syndrome patients. These results suggest that nutritional interventions and lifestyle modifications may be useful strategies to decrease the cardiovascular risk in this population.

HIV therapy, metabolic syndrome, and cardiovascular risk

People with HIV infection have metabolic abnormalities that resemble metabolic syndrome (hypertriglyceridemia, low high-density lipoprotein cholesterol, and insulin resistance), which is known to predict increased risk of cardiovascular disease (CVD). However, there is not one underlying cause for these abnormalities and they are not linked to each other. Rather, individual abnormalities can be affected by the host response to HIV itself, specific HIV drugs, classes of HIV drugs, HIV-associated lipoatrophy, or restoration to health. Furthermore, one component of metabolic syndrome, increased waist circumference, occurs less frequently in HIV infection. Thus, HIV infection supports the concept that metabolic syndrome does not represent a syndrome based on a common underlying pathophysiology. As might be predicted from these findings, the prevalence of CVD is higher in people with HIV infection. It remains to be determined whether CVD rates in HIV infection are higher than might be predicted from traditional risk factors, including smoking.

Metabolic syndrome: a major risk factor for atherosclerosis in HIV-infected patients (SHIVA study)

OBJECTIVE

Metabolic syndrome (MetS) is directly related to a high incidence of cardiovascular disease in the general population. The association is more doubtful among HIV-infected patients, although MetS has an elevated prevalence in this population. We explored the impact of MetS on early atherosclerosis markers.

RESEARCH DESIGN AND METHODS

All HIV-infected outpatients followed at the Brest University Hospital were included in this cross-sectional hospital-based study (SHIVA study, France) (n=154). The MetS status (NCEP ATPIII definition, at least three of these five criteria: fasting glucose, triglycerides, HDL-C, waist circumference and hypertension.) of each patient was analyzed (Mann-Whitney test) according to carotid intima-media thickness, number of plaques, and a combined cardiovascular score.

RESULTS

After exclusion of 6 patients treated with statins or insulin or both, MetS status was available for 140 (90.9%) patients and positive for 10 (7.1%). MetS status was due predominantly to blood glucose and triglyceride levels and was strongly correlated with all atherosclerosis markers (p < or = 0.01).

CONCLUSION

The MetS prevalence in this population is low for a group with HIV infection, even after inclusion of the statin-treated patients (11.4%), but remains higher than among the general population. MetS in this population is probably a heterogeneous cluster of side effects of antiretroviral therapy (high triglycerides, lower HDL-C, and hypertension) and direct effects of HIV (glucose disturbances). Because it is strongly linked to the presence of plaque and intimal thickness, it is a pertinent criterion for deciding about cardiovascular prevention.

HIV and menopause: a review

The use of highly active antiretroviral therapy (HAART) has resulted in dramatic reductions in morbidity and mortality of HIV infected individuals. With increasing life expectancy, a growing population of women will experience menopausal transitions while infected with HIV. Changes associated with menopause may affect HIV disease progression, and HIV-infected women may experience menopause in a different way from that of uninfected women. Age at natural menopause among non-HIV-infected white and Hispanic women is on the average 51 years, and that of African American women is 49 years. Several studies have shown that the mean age of menopause in HIV-infected women is 47-48 years. This is likely due to factors other than HIV infection that predict early menopause, such as drug use, smoking, and low socioeconomic status. It may be difficult to separate out HIV symptoms from menopausal symptoms. The additive effects of menopause, HIV infection, and HAART on changes involving bone, lipid, and glucose metabolism need further investigation. Likewise, there is a need for a better understanding of the prevalence and manifestations of depression among these women.

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.

Cystatin C level as a marker of kidney function in human immunodeficiency virus infection: the FRAM study

BACKGROUND

Although studies have reported a high prevalence of end-stage renal disease in human immunodeficiency virus (HIV)-infected individuals, little is known about moderate impairments in kidney function. Cystatin C measurement may be more sensitive than creatinine for detecting impaired kidney function in persons with HIV.

METHODS

We evaluated kidney function in the Fat Redistribution and Metabolic Change in HIV Infection (FRAM) cohort, a representative sample of 1008 HIV-infected persons and 290 controls from the Coronary Artery Risk Development in Young Adults (CARDIA) study in the United States.

RESULTS

Cystatin C level was elevated in HIV-infected individuals; the mean +/- SD cystatin C level was 0.92 +/- 0.22 mg/L in those infected with HIV and 0.76 +/- 0.15 mg/L in controls (P < .001). In contrast, both mean creatinine levels and estimated glomerular filtration rates appeared similar in HIV-infected individuals and controls (0.87 +/- 0.21 vs 0.85 +/- 0.19 mg/dL [to convert to micromoles per liter, multiply by 88.4] [P = .35] and 110 +/- 26 vs 106 +/- 23 mL/min/1.73 m(2) [P = .06], respectively). Persons with HIV infection were more likely to have a cystatin C level greater than 1.0 mg/L (OR, 9.8; 95% confidence interval, 4.4-22.0 [P <.001]), a threshold demonstrated to be associated with increased risk for death and cardiovascular and kidney disease. Among participants with HIV, potentially modifiable risk factors for kidney disease, hypertension, and low high-density lipoprotein concentration were associated with a higher cystatin C level, as were lower CD4 lymphocyte count and coinfection with hepatitis C virus (all P < .001).

CONCLUSIONS

Individuals infected with HIV had substantially worse kidney function when measured by cystatin C level compared with HIV-negative controls, whereas mean creatinine levels and estimated glomerular filtration rates were similar. Cystatin C measurement could be a useful clinical tool to identify HIV-infected persons at increased risk for kidney and cardiovascular disease.

HIV infection and high density lipoprotein metabolism

HIV infection and its treatment are associated with dyslipidemia, including hypoalphalipoproteinemia, and increased risk of cardiovascular disease. Parameters of HDL metabolism in HIV-positive patients were investigated in a cross-sectional study. The following groups of subjects were selected: (i) 25 treatment-naïve HIV-infected patients or HIV-infected patients on long therapy break, (ii) 28 HIV-infected patients currently treated with protease inhibitors, and (iii) 33 HIV-negative subjects. Compared to the HIV-negative group, all groups of HIV-infected patients were characterized by significantly elevated triglyceride and apolipoprotein B levels, mass and activity of lecithin cholesterol acyl transferase and cholesteryl ester transfer protein (p<0.01). Total and LDL cholesterol was lower in treatment-naïve HIV-infected group only. HDL cholesterol and prebeta(1)-HDL were significantly lower in all HIV-infected groups (p<0.05), while mean levels of apolipoprotein A-I (apoA-I) and ability of plasma to promote cholesterol efflux were similar in all groups. We found a positive correlation between apoA-I and levels of CD4+ cells (r(2)=0.3, p<0.001). Plasma level of phospholipid transfer protein was reduced in the group on antiretroviral therapy. Taken together these results suggest that HIV infection is associated with modified HDL metabolism re-directing cholesterol to the apoB-containing lipoproteins and likely reducing the functionality of reverse cholesterol transport.

Human immunodeficiency virus infection and macrophage cholesterol metabolism

Macrophages play a central role in the pathogenesis of atherosclerosis and are also a host for a number of viruses, most importantly, HIV. Many viruses, including HIV, require cholesterol for their replication and as a structural element. Cholesterol also plays a pivotal role in innate antiviral immune responses. Although impairing innate immune response by increasing cell cholesterol content may be a deliberate strategy used by a pathogen to improve its infectivity, enhancing the risk of atherosclerosis is likely a byproduct. Consistent association between HIV infection and elevated risk of atherosclerosis suggested a connection between virus-induced changes in cholesterol metabolism and atherogenesis, but the mechanisms of such connection have not been identified. We describe in this review various mechanisms enabling viruses to exploit macrophage pathways of cholesterol metabolism, thus diverting cholesterol for a purpose of increasing viral replication and/or for altering innate immune responses. To alter the cellular cholesterol content, viruses "hijack" the pathways responsible for maintaining intracellular cholesterol metabolism. The damage to these pathways by viral infection may result in the inability of macrophages to control cholesterol accumulation and may lead to formation of foam cells, a characteristic feature of atherosclerosis. Further elucidation of the mechanisms connecting viral infection and macrophage cholesterol metabolism may be fruitful for developing approaches to treatment of atherosclerosis and viral diseases.

The management of dyslipidaemias in antiretroviral-treated HIV infection: a systematic review

OBJECTIVES

The aim of the study was to assess the currently available evidence concerning the management of dyslipidaemias in HIV-infected individuals treated with antiretroviral therapy.

METHODS

Randomized trials, published within the 5 years preceding 5 October 2005, were identified in PubMed Medline, Embase, and The Cochrane Central Register of Controlled Trials. Studies were then included or excluded, dependent on their meeting inclusion/exclusion criteria. The evidence obtained in the studies that were included was assessed using methods employed by the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

Thirteen relevant trials were identified, concerning the use of statins, fibrates, antiretroviral drug switches and insulin-sensitizing drugs. Most contained small numbers of trial participants.

CONCLUSIONS

Most studies suggested beneficial effects and satisfactory safety profiles for the interventions studied. However, the insulin-sensitizing drug rosiglitazone appeared to have some detrimental effects on lipid profiles. With the small numbers of participants in the majority of studies, these studies were likely to have been inadequately powered to assess the effects of the interventions examined. Larger trials are therefore necessary.

HIV-positive patients with nonalcoholic fatty liver disease have a lower body mass index and are more physically active than HIV-negative patients

OBJECTIVE

To determine whether the clinical and metabolic features associated with nonalcoholic fatty liver disease (NAFLD) are similar between HIV-positive and HIV-negative male subjects.

METHODS

Twenty-six HIV-positive and 25 HIV-negative subjects with liver biopsy-proven NAFLD were compared for liver histology (extent of steatosis, steatosis grading, and fibrosis staging), blood biochemistry (glucose, insulin, C-peptide, hemoglobin A1c, and lipid profile), insulin resistance (IR) using a homeostasis model assessment, anthropometry (body mass index [BMI], waist circumference, and arm muscle area), dietary intake, and physical activity.

RESULTS

The 2 groups were similar for age, liver histology, and IR. HIV-positive patients had a lower BMI (26.3 +/- 0.5 vs. 30.2 +/- 1.0 kg/m; P = 0.001) and lower percentage of fat mass (19.4 +/- 0.9 vs. 22.7 +/- 1.2; P = 0.026) when compared with HIV-negative patients. Although caloric intake was similar between groups, HIV-positive patients had a higher physical activity level (8.3 +/- 1.6 vs. 4.1 +/- 0.8 units of exercise per day; P = 0.029). Blood triglycerides were significantly higher (3.14 +/- 0.39 vs. 1.86 +/- 0.20 mmol/L; P = 0.006) in HIV-positive patients.

CONCLUSION

Although NAFLD was similar between the 2 groups, HIV-positive patients had a lower BMI and were more physically active compared with HIV-negative patients. This may suggest that in HIV, NAFLD is associated with factors other than those related to body fatness, such as HIV infection and treatment.

Gene expression profiling of rat liver reveals a mechanistic basis for ritonavir-induced hyperlipidemia

The molecular mechanisms of action of a HIV protease inhibitor, ritonavir, on hepatic function were explored on a genomic scale using microarrays comprising genes expressed in the liver of Sprague-Dawley rats (Rattus norvegicus). Analyses of hepatic transcriptional fingerprints led to the identification of several key cellular pathways affected by ritonavir treatment. These effects were compared to a compendium of gene expression responses for 52 unrelated compounds and to other protease inhibitors, including atazanavir and two experimental compounds. We identified genes involved in cholesterol and fatty acid biosynthesis, as well as genes involved in fatty acid and cholesterol breakdown, whose expressions were regulated in opposite manners by ritonavir and bezafibrate, a hypolipidemic agonist of the peroxisome proliferator-activated receptor alpha. Ritonavir also upregulated multiple proteasomal subunit transcripts as well as genes involved in ubiquitination, consistent with its known inhibitory effect on proteasomal activity. We also tested three other protease inhibitors in addition to ritonavir. Atazanavir did not impact ubiquitin or proteasomal gene expression, although the two other experimental protease inhibitors impacted both proteasomal gene expression and sterol regulatory element-binding protein-activated genes, similar to ritonavir. Identification of key metabolic pathways that are affected by ritonavir and other protease inhibitors will enable us to understand better the downstream effects of protease inhibitors, thus leading to better drug design and an effective method to mitigate the side effects of this important class of HIV therapeutics.

Comparison of direct and indirect measurement of LDL-C in HIV-infected individuals: ACTG 5087

BACKGROUND

Hypertriglyceridemia is common in HIV-infected individuals on antiretroviral therapy. Triglyceride (TG) levels >400 mg/dL interfere with the accurate determination of low-density lipoproteins (LDL-C) by the Friedewald equation, making it difficult to assess coronary heart disease risk.

OBJECTIVE

The objective of this study is to compare the agreement of the direct LDL-C assay and the Friedewald equation with a reference ultracentrifugation method in the estimation of LDL-C concentrations.

METHOD

Samples from ACTG 5087 were assayed by ultracentrifugation and a direct enzymatic assay and calculated using the Friedewald equation.

RESULTS

In subjects with TG <400 mg/dL (n = 271), 90% of the direct LDL-C values and Friedewald calculations were within 30 mg/dL and 32 mg/dL of the ultracentrifugation values, respectively. With TG > or = 400 mg/dL (n = 186), 90% of the direct assay and Friedewald observations were within 68 mg/dL and 120 mg/dL of the ultracentrifugation results, respectively. Only 27% of the LDL-C values were within 15 mg/dL of the ultracentrifugation LDL-C results for direct assay and 16.3% for the Friedewald equation.

CONCLUSION

The direct LDL-C assay and the calculated LDL-C values did not display adequate agreement with the reference ultracentrifugation method. In subjects with TG >400 mg/dL, the direct assay overestimates the actual LDL-C whereas the Friedewald calculation underestimates the actual LDL. Clinical usage of these methods may lead to misclassification of the severity of dyslipidemia, resulting in improper management.

Metabolic effects of protease inhibitor-sparing antiretroviral regimens given as initial treatment of HIV-1 Infection (AIDS Clinical Trials Group Study A5095)

OBJECTIVE

To assess metabolic changes after initiation of protease inhibitor (PI)-sparing regimens in antiretroviral-naive patients.

METHODS

Metabolic changes were analyzed within the triple-nucleoside (zidovudine [ZDV]/lamivudine [3TC]/abacavir [ABC])-containing, 3-drug efavirenz (EFV) [ZDV/3TC + EFV]-containing, and 4-drug EFV [ZDV/3TC/ABC + EFV]-containing arms of the AIDS Clinical Trials Group multicenter trial A5095. Metabolic values were compared with published US general population norms.

RESULTS

From week 0 to week 24, all arms exhibited similar mild median increases in glucose and decreases in insulin sensitivity, whereas changes in lipids were greater in the ZDV/3TC + EFV and ZDV/3TC/ABC + EFV arms than in the ZDV/3TC/ABC arm: triglyceride (TG; 7, 18, and -1 mg/dL, respectively), total cholesterol (TC; 23, 28, and 5 mg/dL, respectively), low-density lipoprotein cholesterol (LDL-C; 9, 14, and 1 mg/dL, respectively), and high-density lipoprotein cholesterol (HDL-C; 10, 10, and 5 mg/dL, respectively). Adjusted mean study lipid values of all study participants at week 0 and week 96 compared with those of the National Health and Nutrition Examination Survey (NHANES) 1999 through 2002 values were: TG (148, 187, and 123 mg/dL, respectively), TC (164, 195, and 203 mg/dL, respectively), HDL-C (35, 47, and 51 mg/dL, respectively), and LDL-C (101, 117, and 123 mg/dL, respectively) (P < or = 0.005 for each value vs. NHANES values).

CONCLUSIONS

Similar mild increases in glucose and decreases in insulin sensitivity were observed in all regimens, whereas lipids were modestly higher in the EFV-containing arms. Compared with general population norms, the metabolic dysfunctions of concern after these PI-sparing therapies were increasingly abnormal TC and lower (but improved relative to baseline) HDL-C levels.

Human immunodeficiency virus impairs reverse cholesterol transport from macrophages

Several steps of HIV-1 replication critically depend on cholesterol. HIV infection is associated with profound changes in lipid and lipoprotein metabolism and an increased risk of coronary artery disease. Whereas numerous studies have investigated the role of anti-HIV drugs in lipodystrophy and dyslipidemia, the effects of HIV infection on cellular cholesterol metabolism remain uncharacterized. Here, we demonstrate that HIV-1 impairs ATP-binding cassette transporter A1 (ABCA1)-dependent cholesterol efflux from human macrophages, a condition previously shown to be highly atherogenic. In HIV-1–infected cells, this effect was mediated by Nef. Transfection of murine macrophages with Nef impaired cholesterol efflux from these cells. At least two mechanisms were found to be responsible for this phenomenon: first, HIV infection and transfection with Nef induced post-transcriptional down-regulation of ABCA1; and second, Nef caused redistribution of ABCA1 to the plasma membrane and inhibited internalization of apolipoprotein A-I. Binding of Nef to ABCA1 was required for down-regulation and redistribution of ABCA1. HIV-infected and Nef-transfected macrophages accumulated substantial amounts of lipids, thus resembling foam cells. The contribution of HIV-infected macrophages to the pathogenesis of atherosclerosis was supported by the presence of HIV-positive foam cells in atherosclerotic plaques of HIV-infected patients. Stimulation of cholesterol efflux from macrophages significantly reduced infectivity of the virions produced by these cells, and this effect correlated with a decreased amount of virion-associated cholesterol, suggesting that impairment of cholesterol efflux is essential to ensure proper cholesterol content in nascent HIV particles. These results reveal a previously unrecognized dysregulation of intracellular lipid metabolism in HIV-infected macrophages and identify Nef and ABCA1 as the key players responsible for this effect. Our findings have implications for pathogenesis of both HIV disease and atherosclerosis, because they reveal the role of cholesterol efflux impairment in HIV infectivity and suggest a possible mechanism by which HIV infection of macrophages may contribute to increased risk of atherosclerosis in HIV-infected patients.

HIV1-Nef impairs ABCA1-dependent cholesterol efflux from infected macrophages, promoting the transformation of virally infected macrophages into foam cells (a condition that may put HIV patients at risk for atherosclerosis).

Effects of high-intensity endurance and resistance exercise on HIV metabolic abnormalities: a pilot study

The purposes of this pilot study were to examine the effects of a 16-week supervised high-intensity combined endurance and resistance exercise training program on HIV-associated metabolic abnormalities (abdominal adiposity, dyslipidemia, and insulin resistance) and to explore methodological issues related to the design and implementation of the research protocol in preparation for a randomized controlled trial. A one-group pretest-posttest design was used, with outcomes measured at baseline and within 1 week after the conclusion of the training program. The exercise program consisted of 16 weeks (preceded by a 2-week phase-in period) of three endurance sessions (20 min at 70%-80% of VO (2max)) and two resistance sessions per week (one set of 8-10 repetitions at 80% of one-repetition maximum on seven exercises). Outcome measures included lipid levels (total, high-density lipoprotein, and low-density lipoprotein cholesterol and triglycerides), visceral and subcutaneous adipose area measured by electron beam tomography, fat and lean mass of trunk and limbs measured by dual-energy X-ray absorptiometry, and insulin sensitivity measured by the homeostatic model assessment. Nine participants were recruited, 5 of whom completed the intervention and had pretest and posttest data available for analyses. Aerobic capacity and strength improved over the course of the intervention. Statistically significant decreases were found for total and trunk fat mass (1,324.9 g [+/-733.6] and 992.8 g [+/-733.6], respectively). Triglycerides decreased by 59 mg/dL (+/-69.88), and insulin sensitivity decreased by 15.7% (+/-41.7%), neither of which was a statistically significant change. Results suggest that further testing of the combined exercise intervention in a randomized controlled design is warranted.

Incidence of metabolic syndrome in a cohort of HIV-infected adults and prevalence relative to the US population (National Health and Nutrition Examination Survey)

BACKGROUND

Metabolic syndrome increases the risk of cardiovascular outcomes and type II diabetes. Most of the metabolic abnormalities defining metabolic syndrome are observed in HIV.

OBJECTIVE

To determine the incidence and risk factors for metabolic syndrome in HIV-infected adults in the Nutrition for Healthy Living (NFHL) study (2000-2003) and prevalence relative to the findings of the National Health and Nutrition Examination Survey (NHANES) (1999-2002).

METHODS

Metabolic syndrome is > or =3 of the following: hypertriglyceridemia, low high-density lipoprotein (HDL) cholesterol, hypertension, abdominal obesity, and high serum glucose. The baseline prevalence of metabolic syndrome in the NFHL study (n = 477) was compared to that in the NHANES (n = 1876), adjusted for age, race, gender, poverty, exercise, and diet.

RESULTS

Almost one quarter of NFHL subjects had metabolic syndrome. Most with metabolic syndrome (77%) had low HDL and hypertriglyceridemia plus > or =1 additional abnormality. The prevalence of metabolic syndrome was significantly lower in HAART and non-HAART users compared with NHANES participants unadjusted for body mass index (BMI). After adjustment for BMI, it was no longer significant but the trend remained. The incidence of metabolic syndrome in the NFHL study was higher with increasing viral load, higher BMI, higher trunk-to-limb fat ratio, and Kaletra (lopinavir/ritonavir) or didanosine (ddI) use and lower among college-educated persons.

CONCLUSIONS

Metabolic syndrome is mostly diagnosed through low HDL and high triglycerides in HIV. The risk of developing the syndrome is related to HIV, specific medications, and body fat.

Current Clinical Issues Impacting the Lives of Patients Living With HIV/AIDS

By significantly delaying the onset of AIDS, highly active antiretroviral therapy (HAART) decreases the high rates of mortality and morbidity previously associated with HIV type 1 infection. However, to gain the therapeutic benefits of HAART, patients must commit to lifelong therapy, which carries an increased risk of multiple metabolic comorbidities, including dyslipidemia and hyperglycemia. Hyperlipidemia associated with HAART can be accompanied by abnormal accumulation of adipose tissue in the abdominal and dorsocervical regions, collectively known as lipodystrophy. Additionally, hyperglycemia associated with HAART causes development of type 2 diabetes mellitus. Moreover, patients experiencing adverse metabolic effects associated with HAART have an increased risk for developing cardiovascular disease. Currently, metabolic comorbidities in patients infected with HIV are managed by interventional pharmacotherapy. However, because HAART regimens already have such high pill burdens, treatment of comorbidities with additional drugs may lead to nonadherence. This article will review the differential metabolic effects of various HAART regimens and the clinical implications for patients living with HIV/AIDS.

Non-nucleoside reverse transcriptase inhibitors: a review

Non-nucleoside reverse transcriptase inhibitors form the backbone of antiretroviral treatment for many HIV-infected individuals. The tolerability, pill burden and efficacy associated with this class of agents make them a frequent choice for first-line therapy. Here we review nevirapine and efavirenz in terms of efficacy, resistance and toxicity, focusing particularly on the use of nevirapine to prevent mother-to-child transmission in developing countries.

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.

Tumor necrosis factor-alpha genetic predisposing factors can influence clinical severity in nephropathia epidemica

Severe human infection with Hantavirus is characterized by high fever, cold chills, thrombocytopenia, arterial hypotension, acute renal failure, and/or adult respiratory distress syndrome (ARDS)-like pulmonary involvement, but the clinical course varies greatly between individuals. We investigated whether genetically determined differences in tumor necrosis factor (TNF)-alpha production can influence the severity of Hantavirus disease. We studied a TNF-alpha single-nucleotide promoter polymorphism (SNP) at position -238 (a guanine [G]-to-adenine [A] transition) and ex vivo TNF-alpha production in a recall study of 36 Belgian patients who had a serologically proven form of Puumala virus-induced Hantavirus infection with the kidney as main target organ. In our study, the highest creatinine levels were found in patients with the lowest ex vivo TNF-alpha production. Creatinine levels correlated inversely with TNF-alpha production (R = -0.35, p < 0.05). The number of thrombocytes was significantly lower in patients with the GA-238 genotype (low TNF-alpha producers) compared with patients with the GG-238 genotype. In our study, genetically determined low production of TNF-alpha was associated with some parameters indicating a more severe clinical course of Puumala Hantavirus infection in humans, possibly by impaired activation of TNF-alpha-dependent antiviral mechanisms, which could in turn result in decreased clearance of Hantavirus.

Lipid lowering effects of Momordica charantia (Bitter Melon) in HIV-1-protease inhibitor-treated human hepatoma cells, HepG2

1. Hyperlipidemic effects of HIV-1-protease inhibitors (PI) are associated with increased hepatic production of triglyceride (TG)-rich lipoproteins, rather than lipoprotein clearance. PI are known to increase apolipoprotein B (apoB) secretion, apoC-III mRNA expression and decrease apoA-1 secretion. Nutritional therapy remains an important strategy to manage PI-associated hyperlipidemia. 2. This study investigated the in vitro efficacy of Asian vegetable, Momordica charantia or bitter melon (BM) to ameliorate PI-associated apoB and lipid abnormalities in HepG2 cells. 3. Our study demonstrates that bitter melon juice (BMJ) significantly reduced apoB secretion and apoC-III mRNA expression and normalized apoA-I expression in PI-treated HepG2 cells. BMJ also significantly reduced cellular TG and microsomal TG transfer protein, suggesting that lipid bioavailability and lipidation of apoB assembly may play a role in decreased apoB secretion. 4. Identifying molecular targets of BM may offer alternative dietary strategies to decrease PI-associated hyperlipidemia and improve quality of life among HIV-1-infected patients.

Use of tenofovir disoproxil fumarate and emtricitabine combination in HIV-infected patients

With the continuing spread of HIV infection, particularly in developing countries, cost-effective treatment for its management is a high priority. Truvada (Gilead Sciences) is a single combination pill of the nucleotide reverse transcriptase inhibitors tenofovir disoproxil fumarate and emtricitabine, which is used once daily. It is anticipated to be a clinically potent combination that is free of short-term irritating toxicity. The drug has recently been licensed but there are currently little clinical efficacy data regarding its use. The limited published data have indicated that emtricitabine and lamivudine have equivalent potency, and randomised controlled trials have produced evidence of the efficacy of lamivudine combined with tenofovir disoproxil fumarate in a regimen containing either the non-nucleoside reverse transcriptase inhibitor efavirenz or a protease inhibitor lopinavir/ritonavir. In these trials, long-term durability data are available for < or = 96 weeks.

Recent studies of lipoprotein kinetics in the metabolic syndrome and related disorders

PURPOSE OF REVIEW

Dyslipoproteinemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. Recent in-vivo kinetic studies of dyslipidemia in the metabolic syndrome are reviewed here.

RECENT FINDINGS

The dysregulation of lipoprotein metabolism may be caused by a combination of overproduction of VLDL apolipoprotein B-100, decreased catabolism of apolipoprotein B-containing particles, and increased catabolism of HDL apolipoprotein A-I particles. Nutritional modifications and increased physical exercise may favourably alter lipoprotein transport by collectively decreasing the hepatic secretion of VLDL apolipoprotein B and the catabolism of HDL apolipoprotein A-I, as well as by increasing the clearance of LDL apolipoprotein B. Conventional and new pharmacological treatments, such as statins, fibrates and cholesteryl ester transfer protein inhibitors, can also correct dyslipidemia by several mechanisms, including decreased secretion and increased catabolism of apolipoprotein B, as well as increased secretion and decreased catabolism of apolipoprotein A-I.

SUMMARY

Kinetic studies provide a mechanistic insight into the dysregulation and therapy of lipid and lipoprotein disorders. Future research mandates the development of new tracer methodologies with practicable in-vivo protocols for investigating fatty acid turnover, macrophage reverse cholesterol transport, cholesterol transport in plasma, corporeal cholesterol balance, and the turnover of several subpopulations of HDL particles.