Association of Endothelial Dysfunction and Antiretroviral Therapy in Early HIV Infection

Connection Between HIV and Mitochondria in Cardiovascular Disease and Implications for Treatments

HIV infection and antiretroviral therapy alter mitochondrial function, which can progressively lead to mitochondrial damage and accelerated aging. The interaction between persistent HIV reservoirs and mitochondria may provide insight into the relatively high rates of cardiovascular disease and mortality in persons living with HIV. In this review, we explore the intricate relationship between HIV and mitochondrial function, highlighting the potential for novel therapeutic strategies in the context of cardiovascular diseases. We reflect on mitochondrial dynamics, mitochondrial DNA, and mitochondrial antiviral signaling protein in the context of HIV. Furthermore, we summarize how toxicities related to early antiretroviral therapy and current highly active antiretroviral therapy can contribute to mitochondrial dysregulation, chronic inflammation, and poor clinical outcomes. There is a need to understand the mechanisms and develop new targeted therapies. We further consider current and potential future therapies for HIV and their interplay with mitochondria. We reflect on the next-generation antiretroviral therapies and HIV cure due to the direct and indirect effects of HIV persistence, associated comorbidities, coinfections, and the advancement of interdisciplinary research fields. This includes exploring novel and creative approaches to target mitochondria for therapeutic intervention.

Association of HIV infection with clinical features and outcomes of patients with aortic aneurysms

Data on the characteristics and outcomes of hospitalized patients with aortic aneurysms (AA) and HIV remain scarce. This is a cohort study of hospitalized adult patients with a diagnosis of AA from 2013 to 2019 using the US National Inpatient Readmission Database. Patients with a diagnosis of HIV were identified. Our outcomes included trends in hospitalizations and comparison of clinical characteristics, complications, and mortality in patients with AA and HIV compared to those without HIV. Among 1,905,837 hospitalized patients with AA, 4416 (0.23%) were living with HIV. There was an overall age-adjusted increase in the rate of HIV among patients hospitalized with AA over the years (14-29 per 10,000 person-years; age-adjusted p-trend < 0.001). Patients with AA and HIV were younger than those without HIV (median age: 60 vs 76 years, p < 0.001) and were less likely to have a history of smoking, hypertension, dyslipidemia, diabetes mellitus, and obesity. Thoracic aortic aneurysms were more prevalent in those with HIV (37.5% vs 26.7%, p < 0.001). On multivariable logistic regression, HIV was not associated with increased risk of aortic rupture (OR: 0.79; 95% CI: 0.61-1.01, p = 0.06), acute aortic dissection (OR: 0.73; 95% CI: 0.51-1.06, p = 0.3), readmissions (OR: 1.04; 95% CI: 0.95-1.13, p = 0.4), or aortic repair (OR: 0.89; 95% CI: 0.79-1.00, p = 0.05). Hospitalized patients with AA and HIV had a lower crude mortality rate compared to those without HIV (OR: 0.75 (0.63-0.91), p = 0.003). Hospitalized patients with AA and HIV likely constitute a distinct group of patients with AA; they are younger, have fewer traditional cardiovascular risk factors, and a higher rate of thoracic aorta involvement. Differences in clinical features may account for the lower mortality rate observed in patients with AA and HIV compared to those without HIV.

HIV-associated thrombotic thrombocytopenic purpura (HIV-TTP): A practical guide and review of the literature

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP), a serious thrombotic microangiopathy (TMA), is prevalent in the South African HIV-infected population. The exact pathogenesis of HIV-associated TTP (HIV-TTP) is however still unclear with diagnostic and therapeutic inconsistancies.

METHODS

A systematic review of the published literature regarding HIV-TTP was performed.

RESULTS

HIV-TTP is still associated with significant morbidity and mortality in Africa despite the availability of anti-retroviral therpy (ART). Diagnosis of HIV-TTP requires the presence of a micro-angiopathic haemolytic anaemia with significant red blood cell schistocytes and thrombocytopenia in the absence of another TMA but background activation of the coagulation system and inflammation in HIV infected people can result in diagnostic anbiguity. Plasma therapy in the form of infusion or exchange is successful but expensive, associated with side-effects and not widely available. Adjuvant immunosuppression therapy may of benefit in patients with HIV-TTP and ART must always be optimised. Endothelial dysfunction caused by chronic inflammation and complement activation most likely contributes to the development of HIV-TTP.

CONCLUSION

The role of adjuvant immunomodulating therpy, the therapeutic targets and pathogenic contribution from endothelial dysfunction in HIV-TTP requires further investigation.

Pulse wave velocity demonstrates increased aortic stiffness in newly diagnosed, antiretroviral naïve HIV infected adults: A case-control study

Increased aortic stiffness is an important predictor of cardiovascular disease (CVD). It remains controversial whether HIV infected persons have increased aortic stiffness at the time of HIV diagnosis. An explorative, case-control study was performed using carotid-femoral pulse wave velocity (PWV) in a newly diagnosed, antiretroviral treatment (ART)-naïve cohort with modest baseline cardiovascular risk. We recruited 85 newly diagnosed adults without known CVD from health care facilities in South Africa (43 female; mean age 33). Median CD4 count was 285, IQR 156-393 cells/µL. Twenty two HIV uninfected controls were recruited from the same facilities (8 female; mean age 33). PWV was measured using the Vicorder module (Skidmore Medical, United Kingdom) using a corrective factor of 0.8. The HIV infected group's mean PWV measured 11% higher than controls (5.88 vs 5.28 m/s; P = .02). Median aortic distensibility in HIV infected persons was 18% lower than controls (0.37 vs 0.45 mm Hg-1; P = .009). Multivariate analysis revealed that the difference in PWV between groups remained significant when corrected for age, sex, mean blood pressure and kidney function (mean difference 0.52 m/s; P = .01). Mean blood pressure, estimated glomerular filtration rate, HIV infection per se, age and male sex were important associations with increased PWV. Our study provides evidence for increased aortic stiffness in ART naïve adults already demonstrable at the time of HIV diagnosis. The cohort's young age and recent HIV diagnosis makes atherosclerosis a less likely explanation for the difference. Alternative, potentially reversible, explanations that require further research include vasomotor tone abnormalities and endothelial dysfunction.

Benefits of antiretroviral therapy initiation during acute HIV infection

Objectives: In the last decade, there has been increasing scientific and legislative focus on antiretroviral treatment (ART) for all people living with HIV. Especially early ART initiation, preferably during acute HIV infection, has been named as a promising strategy, both for the individual and for the society. This article will review the benefits and possible future applications of immediate ART initiation during acute HIV infection and explore the remaining hurdles towards this strategy.Results: On an individual level, initiation of ART during acute HIV infection limits the viral reservoir, preserves immune function, and decreases systemic inflammation. In addition, obtaining viral suppression soon after infection can be beneficial for the society by decreasing the chance of onward HIV transmission. Reducing the transmission will reduce HIV incidence and can curtail HIV-related health expenditure. Furthermore, the favorable immunological and virological profile obtained by treating during acute HIV infection will form an ideal starting point for several HIV cure strategies.Conclusions: Initiation of ART during acute HIV infection has shown distinct benefits for the individual, for the society, and for future research on HIV cure. In order to implement this strategy, equal focus should be placed on early diagnosis.

Viral Endothelial Dysfunction: A Unifying Mechanism for COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible virus with significant global impact, morbidity, and mortality. The SARS-CoV-2 virus may result in widespread organ manifestations including acute respiratory distress syndrome, acute renal failure, thromboembolism, and myocarditis. Virus-induced endothelial injury may cause endothelial activation, increased permeability, inflammation, and immune response and cytokine storm. Endothelial dysfunction is a systemic disorder that is a precursor of atherosclerotic vascular disease that is associated with cardiovascular risk factors and is highly prevalent in patients with atherosclerotic cardiovascular and peripheral disease. Several studies have associated various viral infections including SARS-CoV-2 infection with inflammation, endothelial dysfunction, and subsequent innate immune response and cytokine storm. Noninvasive monitoring of endothelial function and identification of high-risk patients who may require specific therapies may have the potential to improve morbidity and mortality associated with subsequent inflammation, cytokine storm, and multiorgan involvement.

Effect of HIV-1 Infection on Angiopoietin 1 and 2 Levels and Measures of Microvascular and Macrovascular Endothelial Dysfunction

Background Individuals infected with HIV have an increased risk of developing cardiovascular disease; yet, the underlying mechanisms remain unknown. Recent evidence has implicated the Tie-2 tyrosine kinase receptor system and its associated ligands ANG1 (angiopoietin 1) and ANG2 (angiopoietin 2) in maintaining vascular homeostasis. In the general population, lower ANG1 levels and higher ANG2 levels are strongly correlated with the development of cardiovascular disease. In this study, we aim to investigate the associations of HIV infection with angiopoietin levels and endothelial dysfunction. Methods and Results In this cross-sectional study, we compared measures of ANG1, ANG2, and endothelial dysfunction using flow-mediated vasodilation of the brachial artery in 39 untreated subjects infected with HIV, 47 treated subjects infected with HIV, and 46 uninfected subjects from the SCOPE (Observational Study of the Consequences of the Protease Inhibitor Era) cohort. Compared with uninfected controls, treated individuals infected with HIV had 53.1% lower mean ANG1 levels (P<0.01) and similar ANG2 levels. On the other hand, untreated individuals infected with HIV had similar ANG1 levels, and 29.2% had higher ANG2 levels (P<0.01) compared with uninfected controls. When compared with individuals with untreated HIV infection, those with treated HIV infection had 56% lower ANG1 levels (P<0.01) and 22% lower ANG2 levels (P<0.01).Both treated and untreated HIV infection were associated with significant impairment in hyperemic velocity, a key measure of microvascular dysfunction (median 61 versus 72 cm/s, P<0.01), compared with uninfected controls (median 73 cm/s). This difference persisted after adjustment for ANG1 and ANG2 levels. Interestingly, when compared with untreated individuals infected with HIV, treated individuals infected with HIV had worse hyperemic velocity (-12.35 cm/s, P=0.05). In contrast, HIV status, ANG1 levels, and ANG2 levels were not associated with macrovascular dysfunction as measured by flow-mediated dilatation and brachial artery diameter, 2 other measures of vascular homeostasis. Conclusions HIV infection affects the balance between levels of ANG1 and ANG2 and may disturb endothelial homeostasis through disruption of vascular homeostasis. Individuals with treated HIV had decreased ANG1 levels and similar ANG2 levels, whereas individuals with untreated HIV had similar ANG1 levels and increased ANG2 levels, suggesting that treatment status may alter the balance between ANG1 and ANG2. HIV also promotes endothelial dysfunction via impairment of microvascular dysfunction, independent of the Tie-2 receptor system; the finding of worse microvascular dysfunction in the setting of treated HIV infection may reflect the impact of viral persistence on the microvasculature or toxicities of specific antiretroviral regimens. Further research to clarify the mechanism of HIV-mediated endothelial dysfunction is necessary to advance treatment of cardiovascular complications of HIV infection.

Cardiometabolic Complications in Youth With Perinatally Acquired HIV in the Era of Antiretroviral Therapy

PURPOSE OF REVIEW

Antiretroviral therapy (ART) scale-up has dramatically reduced rates of pediatric HIV mortality and morbidity. Children living with perinatally acquired HIV (PHIV) are now expected to live through adolescence and well into adulthood, such that adolescents now represent the largest growing population living with HIV. This review aims to discuss the prevalence and mechanisms for cardiometabolic comorbidities in the setting of newer ART regimens and the research gaps that remain.

RECENT FINDINGS

Data highlight the continued risks of subclinical cardiometabolic complications in PHIV in the setting of newer ART. Novel techniques in imaging and omics may help identify early cardiometabolic abnormalities in this young population and potentially identify early changes in the mechanistic pathways related to these changes. Further studies to determine risk and management strategies of the cardiometabolic effects in PHIV adolescents, beyond ART, are warranted. Focus should be on prevention of these complications in youth to avoid new epidemic of diabetes and cardiovascular disease when these youths become aging adults.

The Effects of Acute Aerobic Exercise on Blood Pressure, Arterial Function, and Heart Rate Variability in Men Living With HIV

PURPOSE

This study aims to investigate the effects of acute cycling on blood pressure (BP), arterial function, and heart rate variability (HRV) in men living with HIV (MLHIV) using combined antiretroviral therapy (cART).

METHODS

Twelve MLHIV (48.7 ± 9.2 years; 25.2 ± 2.8 kg m-2) and 13 healthy controls (41.2 ± 9.9 years; 26.3 ± 2.9 kg m-2) performed a cycling bout (ES) (intensity: 50% oxygen uptake reserve; duration: time to achieve 150 kcal-MLHIV: 24.1 ± 5.5 vs. controls: 23.1 ± 3.0 min; p = 0.45), and a 20-min non-exercise session (NES).

RESULTS

At rest (p < 0.05), MLHIV presented higher brachial systolic/diastolic BP (SBP/DBP: 123.2 ± 14.2/76.8 ± 6.3 vs. 114.3 ± 5.1/71.6 ± 2.6 mmHg) and central BP (cSBP/cDBP: 108.3 ± 9.3/76.5 ± 6.5 vs. 101.6 ± 4.9/71.3 ± 4.4 mmHg) vs. controls but lower absolute maximal oxygen uptake (2.1 ± 0.5 vs. 2.5 ± 0.3 L min-1) and HRV indices reflecting overall/vagal modulation (SDNN: 24.8 ± 7.1 vs. 42.9 ± 21.3 ms; rMSSD: 20.5 ± 8.5 vs. 38.1 ± 22.8 ms; pNN50: 3.6 ± 4.2 vs. 13.6 ± 11.3%). DBP postexercise lowered in controls vs. MLHIV (∼4 mmHg, p < 0.001; ES: 0.6). Moreover, controls vs. MLHIV had greater reductions (p < 0.05) in augmentation index (-13.6 ± 13.7 vs. -3.1 ± 7.2% min-1; ES: 2.4), and HRV indices up to 5 min (rMSSD: -111.8 ± 32.1 vs. -75.9 ± 22.2 ms min-1; ES: 3.8; pNN50: -76.3 ± 28.3 vs. -19.0 ± 13.7% min-1; ES: 4.4). Within-group (ES vs. NES; p < 0.05) reductions occurred in controls for SBP (∼10 mmHg, 2 h), DBP (∼6 mmHg, 20, 30, and 70 min), cSBP (∼9 mmHg, 30 min), cDBP (∼7 mmHg, 30 and 70 min), augmentation index (∼10%, 30 min), and pNN50 (∼20%; up to 2 h), while in MLHIV only cSBP (∼6 mmHg, 70 min) and cDBP (∼4 mmHg, 30 min) decreased. Similar increases (up to 5 min) in heart rate (∼22 bpm) and decreases in SDNN (∼18 ms) and rMSSD (∼20 ms) occurred in both groups.

CONCLUSION

MLHIV under cART exhibited attenuated postexercise hypotension vs. healthy controls, which seemed to relate with impairments in vascular function.

Assessment of the impact of HIV infection and anti-retroviral treatment on the cardiometabolic health of pregnant mothers and their offspring (ARTMOMSBABES)

BACKGROUND

The risk of cardiovascular diseases (CVDs) is becoming more prevalent in pregnant women though not much data is available for pregnant women with human immunodeficiency virus (HIV). Foetoplacental vascular endothelial dysfunction is thought to be at the origin of chronic diseases such as diabetes and obesity later on in life. Because HIV and anti-retroviral treatment (ARTs) are associated with endothelial dysfunction, children exposed in utero to these conditions may be at greater risk of developing CVDs. Despite the high prevalence of HIV in pregnant South African women, little is known about the effects of ART on the cardiovascular health of the mother and offspring. Hence, the proposed study intends to investigate how HIV/ARTs may affect the cardiovascular health of the mother and offspring at different time points during the pregnancy and up to 2 years after birth.

METHODS

A longitudinal case-control study in HIV positive pregnant women on ART and HIV negative pregnant women will be conducted. All pregnant women will be assessed for cardio-metabolic risk factors and markers (lipids, anthropometric and glycaemic indies, oxidative stress), hemodynamic status (blood pressure parameters) and vascular function (arterial compliance, retinal microvasculature, uterine artery mean pulsatility index). Child health will be monitored in utero and postnatally via routine foetal health screening, placental integrity, anthropometry, blood pressure parameters, markers of oxidative stress and endothelial function in cord blood and cardiovascular epigenetic markers in urine.

DISCUSSION

There is a paucity of studies in South Africa and sub-Sahara Africa as a whole that utilised a longitudinal study model to assess the effects of ARTs on vascular endothelial changes in pregnant women living with HIV and the cardiometabolic health of their offspring. This study will therefore help to monitor changes in cardiometabolic risk during pregnancy and in children exposed in utero to HIV-infection and ART use. Findings from this study will provide useful information for developing guidelines on the use of ARTs in pregnancy and management of cardiometabolic health of the offspring of HIV positive mothers.

HIV-Infected Naïve Patients Exhibit Endothelial Dysfunction Concomitant with Decreased Natural Antibodies Against Defined Apolipoprotein B Autoantigens

Fundamento:

Fatores de risco definidos para HIV e tradicionais podem estar associados a um aumento de eventos cardiovasculares. Estudos recentes sugerem que a resposta imune humoral à LDL modificada pode estar associada ao processo de aterosclerose.

Objetivos:

Avaliar a presença de anti-LDL oxidada e de peptídeos derivados da Apolipoproteína B no sangue, bem como sua associação à função endotelial na infecção por HIV.

Métodos:

Este estudo incluiu consecutivamente sujeitos com idade, sexo e dados demográficos correspondentes em dois grupos: (1) indivíduos infectados com HIV e naïve para terapia antiviral e (2) indivíduos não infectados. A aterosclerose subclínica foi avaliada pela espessura íntima-média, utilizando-se a ultrassonografia das artérias carótidas. A função endotelial foi determinada pela dilatação mediada por fluxo (DMF) da artéria braquial por ultrassonografia. Os níveis de autoanticorpos (IgM, IgG) de lipoproteínas de baixa densidade antioxidadas (LDL-ox), fragmentos de peptídeos antiapolipoproteína B (peptídeos ApoB-D e 0033G-Cys), e citocina foram avaliados por meio de ELISA.

Resultados:

Os resultados deste estudo não mostraram diferenças na aterosclerose subclínica entre os grupos. Entretanto, os sujeitos infectados com HIV apresentaram uma DMF mais baixa, em comparação com os sujeitos não infectados. Portanto, os sujeitos infectados com HIV apresentaram níveis mais altos de citocinas inflamatórias, títulos de IgG anti-LDL-ox, e IgG anti-ApoB-D. Em contraste, títulos de IgM anti-ApoB-D foram mais baixos em indivíduos infectados com HIV e associados a funções endoteliais diminuídas.

Conclusões:

Os resultados deste estudo mostram que a infecção por HIV, em sujeitos naïve, está associada à disfunção endotelial e à diminuição de anticorpos naturais para antígenos Apo-B.

Relationship between Endothelial Function, Antiretroviral Treatment and Cardiovascular Risk Factors in HIV Patients of African Descent in South Africa: A Cross-Sectional Study

Limited information on the effect of antiretroviral treatment (ART) on vascular function in South Africans of African descent living with human immunodeficiency virus (HIV) is available. The relationship between ART, vascular function and cardiovascular risk factors in South Africans of African ancestry with HIV was therefore studied. This cross-sectional study recruited 146 HIV-positive individuals on ART (HIV⁺ART⁺), 163 HIV-positive individuals not on ART (HIV⁺ART⁻) and 171 individuals without HIV (HIV⁻) in Mthatha, Eastern Cape Province of South Africa. Flow-mediated dilation (FMD) test was performed to assess endothelial function. Anthropometry and blood pressure parameters were measured. Lipid profile, glycaemic indices, serum creatinine as well as CD4 count and viral load were assayed in blood. Urinary albumin to creatinine ratio (ACR) was determined as a marker of cardiovascular risk. Obesity and albuminuria were positively associated with HIV, and HIV⁺ART⁺ participants had significantly higher HDL cholesterol. Dyslipidaemia markers were significantly higher in hypertensive HIV⁺ART⁺ participants compared with the controls (HIV⁺ART⁻ and HIV⁻ participants). FMD was not different between HIV⁺ART⁺ participants and the controls. Moreover, HIV⁺ART⁺ participants with higher FMD showed lower total cholesterol and LDL cholesterol comparable to that of HIV⁻ and HIV⁺ART⁻ participants. A positive relationship between FMD and CD4 count was observed in HIV⁺ART⁺ participants. In conclusion, antiretroviral treatment was associated with cardiovascular risk factors, particularly dyslipidaemia, in hypertensive South Africans of African ancestry with HIV. Although, ART was not associated with endothelial dysfunction, flow-mediated dilatation was positively associated with CD4 count in HIV-positive participants on ART.

HIV-1 Tat Protein Enters Dysfunctional Endothelial Cells via Integrins and Renders Them Permissive to Virus Replication

Previous work has shown that the Tat protein of Human Immunodeficiency Virus (HIV)-1 is released by acutely infected cells in a biologically active form and enters dendritic cells upon the binding of its arginine-glycine-aspartic acid (RGD) domain to the α5β1, αvβ3, and αvβ5 integrins. The up-regulation/activation of these integrins occurs in endothelial cells exposed to inflammatory cytokines that are increased in HIV-infected individuals, leading to endothelial cell dysfunction. Here, we show that inflammatory cytokine-activated endothelial cells selectively bind and rapidly take up nano-micromolar concentrations of Tat, as determined by flow cytometry. Protein oxidation and low temperatures reduce Tat entry, suggesting a conformation- and energy-dependent process. Consistently, Tat entry is competed out by RGD-Tat peptides or integrin natural ligands, and it is blocked by anti-α5β1, -αvβ3, and -αvβ5 antibodies. Moreover, modelling–docking calculations identify a low-energy Tat-αvβ3 integrin complex in which Tat makes contacts with both the αv and β3 chains. It is noteworthy that internalized Tat induces HIV replication in inflammatory cytokine-treated, but not untreated, endothelial cells. Thus, endothelial cell dysfunction driven by inflammatory cytokines renders the vascular system a target of Tat, which makes endothelial cells permissive to HIV replication, adding a further layer of complexity to functionally cure and/or eradicate HIV infection.