HIV disease, metabolic dysfunction and atherosclerosis: A three year prospective study

Changes in the lipid profile in people with HIV after one year of antiretroviral therapy - the significance of immune parameters

Objectives

This study aimed to analyze lipid profiles among people with HIV and observe changes in lipid parameters during 1 year of antiretroviral therapy (ART), with particular reference to immune parameters.

Methods

We analyzed adult newly diagnosed people with HIV (PWH) who started ART, continued uninterruptedly for 1 year and achieved complete viral suppression. Patients were not receiving lipid-lowering therapy. The cluster of differentiation (CD4) count, CD4:CD8 ratio, HIV type 1 viral load, and lipid profile were examined at HIV diagnosis and after 12 months of ART.

Results

The study included 70 patients. Significant increases in total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol and decreases in triglyceride concentrations after 1 year of ART were observed. A baseline CD4 count <200/µl was associated with higher baseline LDL cholesterol (P = 0.036), and female sex with elevated total, LDL, and non-HDL cholesterol (P = 0.005; P = 0.011; P = 0.008). Patients with baseline CD4 counts <200/µl had significantly higher total, LDL, and non-HDL cholesterol (P = 0.033; P = 0.009; P = 0.009) and triglyceride (P = 0.003) levels after 1 year of ART than patients with CD4 levels ≥200/µl.

Conclusions

Lipid parameters should be regularly assessed in all PWH receiving ART, especially in patients with baseline CD4 counts <200/µl.

HDL-based therapeutics: A promising frontier in combating viral and bacterial infections

Low levels of high-density lipoprotein (HDL) and impaired HDL functionality have been consistently associated with increased susceptibility to infection and its serious consequences. This has been attributed to the critical role of HDL in maintaining cellular lipid homeostasis, which is essential for the proper functioning of immune and structural cells. HDL, a multifunctional particle, exerts pleiotropic effects in host defense against pathogens. It functions as a natural nanoparticle, capable of sequestering and neutralizing potentially harmful substances like bacterial lipopolysaccharides. HDL possesses antiviral activity, preventing viruses from entering or fusing with host cells, thereby halting their replication cycle. Understanding the complex relationship between HDL and the immune system may reveal innovative targets for developing new treatments to combat infectious diseases and improve patient outcomes. This review aims to emphasize the role of HDL in influencing the course of bacterial and viral infections and its and its therapeutic potential.

Atherosclerosis and HIV: Exploring Cardiovascular Risks and Management

The advent of antiretroviral therapy has markedly improved the life expectancy of individuals with HIV, leading to a shift in clinical focus from managing opportunistic infections to addressing chronic conditions, such as atherosclerotic cardiovascular disease (ASCVD). Emerging evidence highlights an elevated risk of ASCVD among people living with HIV, characterized by a higher incidence of acute myocardial infarction, ischemic stroke, and heart failure compared with the general population. This review examines the epidemiology, pathophysiology, and management of ASCVD in the context of HIV. It explores the interplay between HIV infection, antiretroviral therapy, and traditional cardiovascular risk factors, underscoring the need for comprehensive cardiovascular risk reduction strategies tailored to people living with HIV. Through synthesizing data from clinical trials, observational studies, and basic research, the review aims to enhance understanding of HIV-associated ASCVD and inform healthcare practices to improve the longevity and quality of life for this patient population.

Inflammatory and Immune Mechanisms for Atherosclerotic Cardiovascular Disease in HIV

Atherosclerotic vascular disease disproportionately affects persons living with HIV (PLWH) compared to those without. The reasons for the excess risk include dysregulated immune response and inflammation related to HIV infection itself, comorbid conditions, and co-infections. Here, we review an updated understanding of immune and inflammatory pathways underlying atherosclerosis in PLWH, including effects of viral products, soluble mediators and chemokines, innate and adaptive immune cells, and important co-infections. We also present potential therapeutic targets which may reduce cardiovascular risk in PLWH.

Cardiovascular Dynamics in HIV: The Influence of Adrenal Function and Nutritional Status

This interdisciplinary review explores the intricate nexus between HIV infection, nutrition, adrenal gland function, and cardiovascular health, highlighting a critical aspect of HIV management often overlooked in current literature. With the advent of antiretroviral therapy, the life expectancy of people living with HIV has dramatically improved, transforming HIV into a manageable chronic condition. However, this success brings forth new challenges, notably an increased risk of cardiovascular diseases among people living with HIV. We examine the normal physiology of the adrenal gland, including its role in mineral metabolism, a crucial facet of nutrition. We discuss the evolution of knowledge tying adrenal pathology to cardiovascular disease. We explore the impact of HIV on adrenal gland findings from a gross pathology perspective, as well as the clinical impact of adrenal insufficiency in HIV. The review further elucidates the role of nutrition in this context, considering the double burden of undernutrition and obesity prevalent in regions heavily affected by HIV. By aggregating findings from longitudinal studies and recent clinical trials, the review presents compelling evidence of increased cardiovascular disease among people living with HIV compared with people without HIV. It highlights the critical role of the adrenal glands in regulating nutrient metabolism and its implications for cardiovascular health, drawing attention to the potential for dietary interventions and targeted therapies to mitigate these risks. This review urges a paradigm shift in the management of HIV, advocating for a holistic approach that incorporates nutritional assessment and interventions into routine HIV care to address the complex interplay between HIV, adrenal function, and cardiovascular health. Through this lens, we offer insights into novel therapeutic strategies aimed at reducing cardiovascular risk in people living with HIV, contributing to the ongoing efforts to enhance the quality of life and longevity in this population.

Association of Lipoprotein(a) with peri-coronary inflammation in persons with and without HIV infection

BACKGROUND

Persons with human immunodeficiency virus (HIV) (PWH) have an increased risk of developing cardiovascular disease (CVD) compared to persons without HIV (PWoH). Lipoprotein(a) [Lp(a)] is a known atherosclerotic risk factor in PWoH, but there are no studies investigating Lp(a) and peri-coronary inflammation.

OBJECTIVE

To investigate whether Lp(a) is associated with peri-coronary inflammation as assessed by the fat attenuation index (FAI) and activated monocytes and T lymphocytes in PWH and PWoH.

METHODS

We measured plasma levels of Lp(a) at study entry in 58 PWH and 21 PWoH without CVD and who had FAI measurements. Associations of Lp(a) with FAI values of the right coronary artery (RCA) and left anterior descending artery were evaluated using multivariable regression models adjusted for potential confounders. Correlations between Lp(a) levels and systemic inflammatory markers and immune cell subsets were examined.

RESULTS

Lp(a) was associated with greater peri-coronary inflammation among PWH compared to PWoH (β=1.73, P=0.019) in the RCA, in adjusted models. Significant correlations were observed with certain inflammatory markers (tumor necrosis factor receptor [TNFR]-I, b=0.295, P<0.001; TNFR-II, b=0.270, P=0.002; high-sensitivity C-reactive protein, b=0.195, P=0.028). Significant correlations were found between Lp(a) levels and several markers of monocyte activation: CD16 -CD163+ (b= -0.199, P=0.024), and CD16 -DR+ MFI (b= -0.179, P=0.042) and T cell subset CD38+CD4+ TEMRA (b= 0.177, P= 0.044).

CONCLUSIONS

Lp(a) was associated with greater peri-coronary inflammation in the RCA in PWH compared to PWoH, as well as with select systemic inflammatory markers and specific subsets of immune cells in peripheral circulation.

Human Immunodeficiency Virus as a Risk Factor for Cardiovascular Disease

The developments in HIV treatments have increased the life expectancy of people living with HIV (PLWH), a situation that makes cardiovascular disease (CVD) in that population as relevant as ever. PLWH are at increased risk of CVD, and our understanding of the underlying mechanisms is continually increasing. HIV infection is associated with elevated levels of multiple proinflammatory molecules, including IL-6, IL-1β, VCAM-1, ICAM-1, TNF-α, TGF-β, osteopontin, sCD14, hs-CRP, and D-dimer. Other currently examined mechanisms include CD4 + lymphocyte depletion, increased intestinal permeability, microbial translocation, and altered cholesterol metabolism. Antiretroviral therapy (ART) leads to decreases in the concentrations of the majority of proinflammatory molecules, although most remain higher than in the general population. Moreover, adverse effects of ART also play an important role in increased CVD risk, especially in the era of rapid advancement of new therapeutical options. Nevertheless, it is currently believed that HIV plays a more significant role in the development of metabolic syndromes than treatment-associated factors. PLWH being more prone to develop CVD is also due to the higher prevalence of smoking and chronic coinfections with viruses such as HCV and HBV. For these reasons, it is crucial to consider HIV a possible causal factor in CVD occurrence, especially among young patients or individuals without common CVD risk factors.

Risk factors and longitudinal changes of dyslipidemia among Chinese people living with HIV receiving antiretroviral therapy

BACKGROUND

Antiretroviral therapy (ART) improved the prognosis of people living with human immunodeficiency virus (HIV) (PLWH). Life-long treatment is required in PLWH and is accompanied by various metabolic abnormalities in the disease course. Data about the epidemiology and the dynamic changes of dyslipidemia in PLWH receiving antiretroviral therapy were scarce in Asian countries. This study aimed to explore the risk factors of dyslipidemia and analyze the longitudinal changes of dyslipidemia among Chinese PLWH receiving HAART.

METHODS

We conducted a longitudinal analysis of PLWH enrolled in two large multicenter clinical trials across China, and outpatients followed at the clinic of Peking Union Medical College Hospital. Demographic data and clinical parameters were collected. The risk factors and longitudinal changes in lipid profiles associated with HIV-1 infection were analyzed. The definition of dyslipidemia was made based on the National Cholesterol Education Program, Adult Treatment Panel (NCEP-ATP) III guidelines.

RESULTS

A total of 1542 PLWH were included. The median follow-up was 6 years. At baseline, the concentrations of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were 4.1 ± 0.91 mmol/L, 1.2 (interquartile ranges [IQR] 0.85-1.75) mmol/L, 1.1 ± 0.37 and 2.4 ± 0.76 mmol/L, respectively. The rate of hypercholesterolemia, hyperglyceridemia, high LDL-C, and low HDL-C were 10.18%, 26.39%, 9.08%, and 44.94%, respectively. The overall prevalence of dyslipidemia was 69.3%, which raised to 84.3% after antiretroviral therapy, substantially higher. CD4/CD8 ratio < 0.3 and viral load > 105 copies/mL were risk factors associated with any subtype of dyslipidemia. A negative correlation between CD8+CD38+ percentage and HDL-C concentration was found. The regimens including efavirenz (EFV) and tenofovir (TDF) showed better lipid profiles. Longitudinal analysis revealed that both the level and the percentage of abnormal TG and HDL-C occurred drastic change in the first 6 months after ART initiation (from 4.07 to 4.41, from 1.11 to 1.28mmol/L, from 26.39 to 31.1% and from 44.94 to 29.5%, respectively).

CONCLUSIONS

The prevalence of dyslipidemia is high in PLWH and increases after ART, mainly represented as high TG and low HDL-C and associated with advanced stage of HIV-1 infection. The greatest changes in lipids occurred in the early stage after initiating ART therapy. The results suggest that dyslipidemia should be monitored and managed when starting ART.

HIV-1 Infection Promotes Cholesterol Aggregation by Inducing miR-33b-5p to Suppress ABCA1 Expression

MicroRNAs play an important role in the interaction between viruses and hosts. In this study, we found that the expression level of miR-33b-5p was markedly increased in human immunodeficiency virus type 1 (HIV-1)-infected cell lines and the serum of person with HIV-1. Further investigation revealed that the level of ATP-binding cassette transporter (ABCA1), which transports cholesterol between intracellular and extracellular compartments to maintain cholesterol homeostasis, was reduced in HIV-1-infected target cells, as the target gene of miR-33b-5p. Furthermore, HIV-1 infection stimulated abnormal lipid transport in macrophages, resulting in lipid accumulation in cells. These changes can be reversed by an miR-33b-5p inhibitor. We discovered a mechanism through which HIV-1 infection caused miR-33b-5p to target ABCA1 and caused aberrant lipid transport, providing a novel method for diagnosing and treating poor lipid metabolism in person with HIV-1.

The anti-atherosclerotic effects of natural polysaccharides: from phenomena to the main mechanisms of action

Polysaccharides (PSs) of plant origin have a variety of biological activities, anti-atherosclerotic including, but their use in atherosclerosis therapy is hindered by insufficient knowledge on the cellular and molecular mechanisms of action. In this review, the influence of several natural PSs on the function of macrophages, viral activity, and macrophage cholesterol metabolism has been discussed considering the tight interplay between these aspects in the pathogenesis of atherosclerosis. The anti-atherosclerotic activities of natural PSs related to other mechanisms have been also explored. Directions for further research of anti-atherosclerotic effects of natural PSs have been outlined, the most promising of which can be nutrigenomic studies.

Cardiovascular toxicity of contemporary antiretroviral therapy

PURPOSE OF REVIEW

HIV treatment has evolved since the introduction of antiretroviral therapy (ART) in the 1990s. Earlier treatment strategies, and the introduction of integrase inhibitors in preferred first-line ART have fundamentally changed cardiovascular side effects due to HIV infection and ART. This review provides an update on cardiovascular toxicity of contemporary ART.

RECENT FINDINGS

Cardiovascular disease (CVD) risk, including heart failure, is still increased in people living with HIV (PLWH). Exposure to older antiretrovirals, including stavudine and zidovudine, still impact on CVD risk through persistent changes in body fat distribution years after discontinuation. Protease inhibitors (PI) and efavirenz have associated metabolic disturbances and increased risk of CVD, although use is decreasing worldwide. Integrase inhibitors and CCR5 antagonists seem to have negligible immediate CVD toxicity. Weight gain on newer antiretrovirals including integrase inhibitors is a reason for concern.

SUMMARY

CVD risk should be monitored carefully in PLWH who were exposed to first generation ART, efavirenz or to PIs. Registries should capture ART use and CVD events to stay informed on actual clinical risk in the current era of rapid initiation on integrase inhibitor-based ART.

MiRNA expression profiling in HIV pathogenesis, disease progression and response to treatment: a systematic review

Aim: A systematic review was conducted to identify the association of miRNA expression with HIV pathogenesis, progression and treatment. Methods: A search of articles was conducted in MEDLINE^®, Cochrane Central Register of Controlled Trials and Global Health. Results: 35 articles were included. Due to the heterogeneity of HIV phenotypes, a harmonization based on key progression parameters was proposed. The hsa-miR-29 family, hsa-miR-146b-5p and hsa-miR-150-5p, are the most frequently differentially expressed in HIV. Direct comparison of studies was not possible due to heterogeneity in biological samples and miRNA analysis techniques. Conclusion: This is the first attempt to systematically identify miRNA's different expression in well-defined patient phenotypes and could represent a helpful way to increase general knowledge in this field.

Infections at the nexus of metabolic-associated fatty liver disease

Metabolic-associated fatty liver disease (MAFLD) is a chronic liver disease that affects about a quarter of the world population. MAFLD encompasses different disease stadia ranging from isolated liver steatosis to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis and hepatocellular carcinoma. Although MAFLD is considered as the hepatic manifestation of the metabolic syndrome, multiple concomitant disease-potentiating factors can accelerate disease progression. Among these risk factors are diet, lifestyle, genetic traits, intake of steatogenic drugs, male gender and particular infections. Although infections often outweigh the development of fatty liver disease, pre-existing MAFLD could be triggered to progress towards more severe disease stadia. These combined disease cases might be underreported because of the high prevalence of both MAFLD and infectious diseases that can promote or exacerbate fatty liver disease development. In this review, we portray the molecular and cellular mechanisms by which the most relevant viral, bacterial and parasitic infections influence the progression of fatty liver disease and steatohepatitis. We focus in particular on how infectious diseases, including coronavirus disease-19, hepatitis C, acquired immunodeficiency syndrome, peptic ulcer and periodontitis, exacerbate MAFLD. We specifically underscore the synergistic effects of these infections with other MAFLD-promoting factors.

Comparison of Predicted Cardiovascular Risk Profiles by Different CVD Risk-Scoring Algorithms between HIV-1-Infected and Uninfected Adults: A Cross-Sectional Study in Tanzania

Purpose

Cardiovascular disease (CVD) risk assessment is a suitable way to differentiate between high-risk individuals requiring intervention and risk modification, and those at low risk. However, concerns have been raised when adopting a CVD-risk prediction algorithm for HIV-infected patients in sub-Saharan Africa.

Patients and Methods

We compared cardiovascular risk profiles between HIV-infected (with and without antiretroviral therapy (ART)) and HIV-uninfected adults as predicted by the American College of Cardiology/American Heart Association (ASCVD) and the Framingham cardiovascular risk score (FRS) algorithms and assessed the concordance of the algorithms in predicting 10-year CVD risk separately in HIV-infected and uninfected groups in a hospital-based cross-sectional study in Tanzania. A cross-sectional hospital-based study including 40 HIV-infected ART-naive, 64 HIV-infected on ART, and 50 HIV-uninfected adults was conducted. Traditional cardiovascular risk factors were determined by standard investigations. The primary outcome was the absolute 10-year CVD risk score based on the two algorithms.

Results

Compared to HIV-uninfected, HIV-infected adults were classified at a higher 10-year CVD risk. ASCVD algorithms predicted a higher proportion of high-risk individuals compared to FRS in both HIV-infected and uninfected groups. The concordance between ASCVD and FRS-lipid algorithms was reasonable for both HIV-infected and uninfected groups though relatively higher in the HIV-uninfected group.

Conclusion

HIV-infected individuals have a higher 10-year cardiovascular risk compared to HIV-uninfected persons. The concordance between ASCVD and FRS-lipid algorithms is reasonable in both HIV-uninfected and infected persons in Tanzania. Development of an HIV-specific algorithm is needed to accurately predict CVD risk in this population at high-risk.

Non-linear optical imaging of atherosclerotic plaques in the context of SIV and HIV infection prominently detects crystalline cholesterol esters

Chronic HIV infection may exacerbate atherosclerotic vascular disease, which at advanced stages presents as necrotic plaques rich in crystalline cholesterol. Such lesions can catastrophically rupture precipitating myocardial infarct and stroke, now important causes of mortality in those living with HIV. However, in this population little is known about plaque structure relative to crystalline content and its chemical composition. Here, we first interrogated plaque crystal structure and composition in atherosclerotic SIV-infected macaques using non-linear optical microscopy. By stimulated Raman scattering and second harmonic generation approaches both amorphous and crystalline plaque lipid was detected and the crystal spectral profile indicated a cholesterol ester (CE) dominated composition. Versus controls, SIV⁺ samples had a greater number of cholesterol crystals (CCs), with the difference, in part, accounted for by crystals of a smaller length. Given the ester finding, we profiled HIV⁺ plaques and also observed a CE crystalline spectral signature. We further profiled plaques from Ldlr^-/- mice fed a high fat diet, and likewise, found CE-dominate crystals. Finally, macrophage exposure to CCs or AcLDL induced auto-fluorescent puncta that co-stained with the LC3B autophagy sensor. In aggregate, we show that atheromatous plaques from mice, macaques and humans, display necrotic cores dominated by esterified CCs, and that plaque macrophages may induce autophagic vesicle formation upon encountering CCs. These findings help inform our knowledge of plaque core lipid evolution and how the process may incite systemic inflammation.

Metabolic Changes in Pediatric HIV-Positive Patients and Potential Lifestyle Interventional Strategies

Metabolic changes in the HIV population have been well-studied, particularly after the advent of antiretroviral therapy. More notably, the emergence of the metabolic syndrome within the HIV population, due to prolonged survival, has led to an increasing rate of cardiovascular occurrence and mortality within the population in adult life. Importance of early intervention in HIV children, particularly lifestyle modifications, is necessary to reduce cardiovascular disease (CVD) risk and mortality in adulthood. Potential clinical interventions include routine anthropometric measurements as a measure of CVD risk, a low saturated fat and high fiber diet, and vigorous aerobic exercise have been shown to decrease CVD risk in the HIV population. The literature review found multiple knowledge gaps due to minimal studies completed on the HIV population and even less on HIV-positive children. Overall, a standardized protocol was required to better care for HIV-positive children and potential future CVD mortality.

Immune activation and arterial stiffness in lean adults with HIV on antiretroviral therapy

Background

Greater T-cell activation was associated with reduced vascular compliance amongst persons living with HIV (PLWH) especially among overweight and obese individuals. There is a paucity of data regarding immune activation and arterial stiffness amongst PLWH in sub-Saharan Africa (SSA).

Objective

To determine the association between immune activation and arterial stiffness in lean PLWH in SSA.

Method

Forty-eight human immunodeficiency virus positive (HIV+) adults on antiretroviral therapy (ART) >5 years and 26 HIV-negative adults, all with BMI < 25 kg/m² and no history of CVD, were enrolled. The relationship of vascular compliance with circulating CD4+ and CD8+ naïve, memory, activated and senescent T cells, and serum 8-isoprostane was assessed by HIV status.

Results

Increased immune activation was observed in the CD4+ and CD8+ T cells of PLWH, 16.7% vs. 8.9% and 22.0% vs. 12.4% respectively; p < 0.001 (both). Furthermore, a higher proportion of senescent CD4+ T cells were associated with a lower carotid-femoral pulse wave velocity (cfPWV; p = 0.01), whilst a higher proportion of activated CD8+ T cells were associated with a lower carotid-radial pulse wave velocity (crPWV; p = 0.04), after adjustment for BMI and age. However, PLWH also had a higher median carotid-femoral augmentation index (cfAiX) (21.1% vs. 6.0%; p < 0.05) in comparison to their HIV controls.

Conclusion

Our population of lean PLWH had increased immune activation and higher cfAiX, a marker of arterial stiffness, compared to HIV-negative persons. The negative association between immune activation and arterial stiffness as measured by crPWV in PLHW on long-term treatment needs further elucidation.

The Role of the ATP-Binding Cassette A1 (ABCA1) in Human Disease

Cholesterol homeostasis is essential in normal physiology of all cells. One of several proteins involved in cholesterol homeostasis is the ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein widely expressed in many tissues. One of its main functions is the efflux of intracellular free cholesterol and phospholipids across the plasma membrane to combine with apolipoproteins, mainly apolipoprotein A-I (Apo A-I), forming nascent high-density lipoprotein-cholesterol (HDL-C) particles, the first step of reverse cholesterol transport (RCT). In addition, ABCA1 regulates cholesterol and phospholipid content in the plasma membrane affecting lipid rafts, microparticle (MP) formation and cell signaling. Thus, it is not surprising that impaired ABCA1 function and altered cholesterol homeostasis may affect many different organs and is involved in the pathophysiology of a broad array of diseases. This review describes evidence obtained from animal models, human studies and genetic variation explaining how ABCA1 is involved in dyslipidemia, coronary heart disease (CHD), type 2 diabetes (T2D), thrombosis, neurological disorders, age-related macular degeneration (AMD), glaucoma, viral infections and in cancer progression.

HIV-related cardiovascular disease: any role for high-density lipoproteins?

The introduction of antiretroviral therapy (ART) has improved the life expectancy of patients infected with human immunodeficiency virus (HIV). However, this population is at an increased risk for noncommunicable diseases, including atherosclerotic cardiovascular disease (CVD). Both ART and viral infection may be potential contributors to the pathophysiology of HIV-related CVD. The mechanisms behind this remain unclear, but it is critical to delineate early biomarkers of cardiovascular risk in the HIV population. In this review, we postulate that potential biomarkers could include alterations to high-density lipoprotein (HDL). Indeed, recent data suggest that HIV and ART may induce structural changes of HDL, thus resulting in shifts in HDL subclass distribution and HDL functionality.

Lipids, biomarkers, and subclinical atherosclerosis in treatment-naive HIV patients starting or not starting antiretroviral therapy: Comparison with a healthy control group in a 2-year prospective study

Objective

To assess the effect of HIV infection and combined antiretroviral therapy (c-ART) on various proatherogenic biomarkers and lipids and to investigate their relationship with subclinical atherosclerosis in a cohort of treatment-naive HIV-infected patients.

Methods

We performed a prospective, comparative, multicenter study of 2 groups of treatment-naive HIV-infected patients (group A, CD4>500 cells/μL, not starting c-ART; and group B, CD4<500 cells/μL, starting c-ART at baseline) and a healthy control group. Laboratory analyses and carotid ultrasound were performed at baseline and at months 12 and 24. The parameters measured were low-density lipoprotein (LDL) particle phenotype, lipoprotein-associated phospholipase A2 (Lp-PLA2), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), sCD14, sCD163, monocyte chemoattractant protein-1(MCP-1), and asymmetric dimethylarginine (ADMA). A linear mixed model based on patient clusters was used to assess differences in biomarkers between the study groups and over time.

Results

The study population comprised 62 HIV-infected patients (group A, n = 31; group B, n = 31) and 22 controls. Age was 37 (30–43) years, and 81% were men. At baseline, the HIV-infected patients had a worse LDL particle phenotype and higher plasma concentration of sCD14, sCD163, hs-CRP, and LDL-Lp-PLA2 than the controls. At month 12, there was an increase in total cholesterol (p = 0.002), HDL-c (p = 0.003), and Apo A-I (p = 0.049) and a decrease in sCD14 (p = <0.001) and sCD163 (p<0.001), although only in group B. LDL particle size increased in group B at month 24 (p = 0.038). No changes were observed in group A or in the healthy controls. Common carotid intima-media thickness increased in HIV-infected patients at month 24 (Group A p = 0.053; group B p = 0.048). Plasma levels of sCD14, sCD163, and hs-CRP correlated with lipid values.

Conclusions

In treatment-naive HIV-infected patients, initiation of c-ART was associated with an improvement in LDL particle phenotype and inflammatory/immune biomarkers, reaching values similar to those of the controls. HIV infection was associated with progression of carotid intima-media thickness.

Comorbidities of HIV infection: role of Nef-induced impairment of cholesterol metabolism and lipid raft functionality

Combination antiretroviral therapy has dramatically changed the outcome of HIV infection, turning it from a death sentence to a manageable chronic disease. However, comorbidities accompanying HIV infection, such as metabolic and cardio-vascular diseases, as well as cognitive impairment, persist despite successful virus control by combination antiretroviral therapy and pose considerable challenges to clinical management of people living with HIV. These comorbidities involve a number of pathological processes affecting a variety of different tissues and cells, making it challenging to identify a common cause(s) that would link these different diseases to HIV infection. In this article, we will present evidence that impairment of cellular cholesterol metabolism may be a common factor driving pathogenesis of HIV-associated comorbidities. Potential implications for therapeutic approaches are discussed.

Exosomes containing HIV protein Nef reorganize lipid rafts potentiating inflammatory response in bystander cells

HIV infection has a profound effect on “bystander” cells causing metabolic co-morbidities. This may be mediated by exosomes secreted by HIV-infected cells and containing viral factors. Here we show that exosomes containing HIV-1 protein Nef (exNef) are rapidly taken up by macrophages releasing Nef into the cell interior. This caused down-regulation of ABCA1, reduction of cholesterol efflux and sharp elevation of the abundance of lipid rafts through reduced activation of small GTPase Cdc42 and decreased actin polymerization. Changes in rafts led to re-localization of TLR4 and TREM-1 to rafts, phosphorylation of ERK1/2, activation of NLRP3 inflammasome, and increased secretion of pro-inflammatory cytokines. The effects of exNef on lipid rafts and on inflammation were reversed by overexpression of a constitutively active mutant of Cdc42. Similar effects were observed in macrophages treated with exosomes produced by HIV-infected cells or isolated from plasma of HIV-infected subjects, but not with exosomes from cells and subjects infected with ΔNef-HIV or uninfected subjects. Mice injected with exNef exhibited monocytosis, reduced ABCA1 in macrophages, increased raft abundance in monocytes and augmented inflammation. Thus, Nef-containing exosomes potentiated pro-inflammatory response by inducing changes in cholesterol metabolism and reorganizing lipid rafts. These mechanisms may contribute to HIV-associated metabolic co-morbidities.

HIV infects only a limited repertoire of cells expressing HIV receptors. Nevertheless, co-morbidities of HIV infection, such as atherosclerosis, dementia, renal impairment, myocardial pathology, abnormal haematopoiesis and others, involve dysfunction of cells that can not be infected by HIV. These co-morbidities persist even after successful application of antiretroviral therapy, when no virus is found in the blood. Many co-morbidities of HIV have a common element in their pathogenesis, impairment of cholesterol metabolism. In this study we show that HIV protein Nef released from infected cells in extracellular vesicles is taken up by un-infected (‘bystander’) cells impairing cholesterol metabolism in these cells. This impairment causes formation of excessive lipid rafts, re-localization of the inflammatory receptors into rafts, and triggers inflammation. These mechanisms may contribute to HIV-associated metabolic co-morbidities. Our work demonstrates how a single viral factor released from infected cells into circulation may cause a pleiotropy of pathogenic responses.