Non-Classical Monocytes and Monocyte Chemoattractant Protein-1 (MCP-1) Correlate with Coronary Artery Calcium Progression in Chronically HIV-1 Infected Adults on Stable Antiretroviral Therapy

Evaluating immunological and inflammatory changes of treatment-experienced people living with HIV switching from first-line triple cART regimens to DTG/3TC vs. B/F/TAF: the DEBATE trial

Background

The aim of this randomized clinical trial (RCT) was to compare immunological changes in virally suppressed people living with HIV (PLWH) switching from a three-drug regimen (3DR) to a two-drug regimen (2DR).

Methods

An open-label, prospective RCT enrolling PLWH receiving a 3DR who switched to bictegravir/emtricitabine/tenofovir alafenamide (B/F/TAF) or dolutegravir/lamivudine (DTG/3TC) was performed. Blood was taken at baseline and months 6 and 12. The primary outcome was the change in CD4+ or CD8+ T-cell counts and CD4/CD8 ratio over time points. The secondary outcomes were the changes in immunological and inflammatory parameters. Parametric mixed-linear models with random intercepts and slopes were fitted separately for each marker after controlling for potential confounders.

Results

Between the two arms (33 PLWH each), there was no difference in CD4+ or CD8+ T cells, CD4/CD8 ratio, and IL-6 trajectories. PLWH switching to DTG/3TC had increased levels of both transitional memory and terminally differentiated CD4+ T cells (arm-time interaction p-value = 0.02) and to a lesser extent for the corresponding CD8+ T-cell subsets (p = 0.09). Significantly lower levels of non-classical monocytes were detected in the B/F/TAF arm at T6 (diff = -6.7 cells/mm3; 95% CI; -16, +2.6; p-value for interaction between arm and time = 0.03). All differences were attenuated at T12.

Conclusion

No evidence for a difference in absolute CD4+ and CD8+ T-cell counts, CD4/CD8 ratio, and IL-6 trajectories by study arm over 12 months was found. PLWH on DTG/3TC showed higher levels of terminally differentiated and exhausted CD4+ and CD8+ T lymphocytes and non-classical monocytes at T6. Further studies are warranted to better understand the clinical impact of our results.

Clinical Trial Registration

https://clinicaltrials.gov, identifier NCT04054089.

Combined effects of loneliness and inflammation on depression in people with HIV

OBJECTIVE

Loneliness is prevalent in people with HIV (PWH) and associated with adverse health-related consequences, including depression. Chronic inflammation has been linked to depression in PWH, though its association with loneliness is less well established. Simultaneous examination of inflammation, loneliness and depression is needed to clarify these relationships. This study investigated the relationship between loneliness and inflammation, and the effects of loneliness and inflammation on depression in PWH.

METHODS

82 PWH who were on suppressive ART (mean age [SD] = 53.2 [9.0]) completed the UCLA Loneliness Scale-Version 3 and the Center for Epidemiologic Studies Depression Scale as part of a comprehensive evaluation. Biomarkers of systemic inflammation (CRP, IL-6, CCL2/MCP-1, sCD14) and coagulation (D-dimer) were measured in blood using commercial immunoassays.

RESULTS

Multivariable linear regression analyses revealed that higher D-dimer, CCL2/MCP-1, and sCD14 were significant predictors of loneliness (ps < .05) while accounting for relevant covariates. Stepwise multiple linear regression models that included loneliness, biomarkers, and their interactions as predictors of depressive symptoms revealed significant main effects of loneliness and CCL2/MCP-1 levels (ps < .05), and a significant loneliness by D-dimer interaction (p < .05) whereby higher D-dimer was associated with increased depressive symptoms only at higher levels of loneliness.

CONCLUSIONS

Increased coagulation activity is associated with loneliness, and in the context of loneliness, may increase risk for depression. Increased inflammation was associated with depression suggesting potentially dissociable underlying biological processes. To the extent that these processes are modifiable, such findings could have important implications in the treatment of loneliness and depression in PWH.

Increased transmigration of intermediate monocytes associated with atherosclerotic burden in people with HIV on antiretroviral therapy

This study evaluated the association between the transmigration of monocyte subpopulations that contributes to atherosclerosis development, along with surrogate biomarkers of inflammation and atherosclerosis, through carotid intima-media thickness (cIMT) measurements of 72 people with HIV (PWH) on suppressive antiretroviral therapy (ART). We found that the transmigration of intermediate monocytes was positively correlated with D-dimer and cIMT, suggesting that intermediate monocytes may have a greater propensity to promote cardiovascular disease (CVD) in PWH on ART.

LDL associates with pro-inflammatory monocyte subset differentiation and increases in chemokine receptor profile expression in African Americans

BACKGROUND

In the United States, African Americans (AAs) have greater risk for Class III obesity and cardiovascular disease (CVD). Previous reports suggest that AAs have a different immune cell profile when compared to Caucasians.

METHODS

The immune cell profile of AAs was characterized by flow cytometry using two experimental setups: ex vivo (N = 40) and in vitro (N = 10). For ex vivo experiments, PBMC were treated with participant serum to understand how lipid contents may contribute to monocyte phenotypic differences. For in vitro experiments, monocytes were low-density lipoprotein (LDL)- or vehicle-treated for four hours and subsequently analyzed by flow cytometry and RT-qPCR.

RESULTS

When PBMCs were treated with participant sera, subsequent multivariable regression analysis revealed that serum triglycerides and LDL levels were associated with monocyte subset differences. In vitro LDL treatment of monocytes induced a phenotypic switch in monocytes away from classical monocytes accompanied by subset-specific chemokine receptor CCR2 and CCR5 expression changes. These observed changes are partially translation-dependent as determined by co-incubation with cycloheximide.

CONCLUSIONS

LDL treatment of monocytes induces a change in monocyte subsets and increases CCR2/CCR5 expression in a subset-specific manner. Understanding the molecular mechanisms could prove to have CVD-related therapeutic benefits, especially in high-risk populations with hyperlipidemia and increased risk for CVD.

Plasma CD16+ Extracellular Vesicles Associate with Carotid Artery Intima-Media Thickness in HIV+ Adults on Combination Antiretroviral Therapy

HIV-infected individuals have increased risk for cardiovascular disease (CVD) despite suppressive antiretroviral therapy (ART). This is likely a result of persistent immune activation and systemic inflammation. Extracellular vesicles (EVs) have emerged as critical mediators of intercellular communication and may drive inflammation contributing to CVD. EVs were characterized in plasma from 74 HIV-infected individuals on combination antiretroviral therapy (cART) and 64 HIV-uninfected controls with paired carotid intima-media thickness (cIMT) assessment. EVs were profiled with markers reflecting lymphoid, myeloid, and endothelial origin. Seventeen plasma inflammatory biomarkers were also assessed. Human umbilical vein endothelial cell (HUVEC) apoptosis was quantified after EV exposure. A significant correlation was observed in HIV-infected participants between cIMT and EVs expressing CD16, and the monocyte-related markers CD4, CD14, and CX3CR1 showed a similar but nonsignificant association with cIMT. No significant correlation between cIMT measurements from HIV-uninfected individuals and EVs was observed. Levels of serum amyloid A, C-reactive protein, and myeloperoxidase significantly correlated with CD14⁺, CD16⁺, and CX3CR1⁺ EVs. No correlation was noted between cIMT and soluble inflammatory markers. HUVECs showed increased necrosis after exposure to the EV-containing fraction of plasma derived from HIV-infected individuals compared to uninfected controls. Our study reveals that EVs expressing monocyte markers correlated with cIMT in HIV-infected individuals on cART. Moreover, EV fractions derived from HIV-infected individuals lead to greater endothelial cell death via necrotic pathways. Collectively, EVs have potential as biomarkers of and therapeutic targets in the pathogenesis of CVD in the setting of treated HIV disease. IMPORTANCE HIV-infected individuals have a 2-fold-increased risk of cardiovascular disease compared with the general population, yet the mechanisms underlying this comorbidity are unclear. Extracellular vesicles have emerged as important mediators in cell-cell communication and, given what we know of their biology, may drive inflammation contributing to cardiovascular disease in this vulnerable population.

Sex modifies the association between HIV and coronary artery disease among older adults in Uganda

INTRODUCTION

Little is known about the epidemiology of coronary artery disease (CAD) in sub-Saharan Africa, where the majority of people living with HIV (PLHIV) live. We assessed the association of HIV with CAD and explored relationships with monocyte activation in sex-stratified analyses of older PLHIV and people without HIV (PWOH) in Uganda.

METHODS

The Ugandan Study of HIV effects on the Myocardium and Atherosclerosis (mUTIMA) follows 100 PLHIV on antiretroviral therapy (ART) and 100 age- and sex-matched PWOH controls in Kampala, Uganda; all >45 years of age with >1 cardiovascular disease risk factor. At the year 2 exam (2017-2019), 189 participants had available coronary calcium score and 165 had coronary CT angiography (CCTA) for this analysis. A subset of participants (n = 107) had both CCTA and fresh whole blood flow cytometry for monocyte phenotyping.

RESULTS

Median age was 57.8 years and 63% were females. Overall, 88% had hypertension, 37% had diabetes and 4% were smokers. Atherosclerotic cardiovascular disease (ASCVD) risk was modestly higher for PWOH, but not statistically significant (median 10-year ASCVD risk 7.2% for PLHIV vs. 8.6% for PWOH, p = 0.09). Median duration of ART was 12.7 years and 86% had suppressed viral load. Despite a high prevalence of risk factors, only 34/165 (21%, 95% CI 15-28%) had any coronary plaque. After adjustment for ASCVD risk score, HIV status was not associated with CAD (OR 0.55, 95% CI 0.23-1.30) but was associated with more severe CAD (segment severity score>3) among those with disease (OR 10.9, 95% CI 1.67-70.45). Females had a trend towards higher odds of CAD among PLHIV (OR 4.1, 95% CI 0.4-44.9), but a trend towards lower odds of CAD among PWOH (OR 0.30; 95% CI 0.07-1.3; HIV*sex interaction p = 0.019). CAD was positively correlated with classical monocytes (r = 0.3, p = 0.012) and negatively correlated with CX3CR1 expression (r = -0.31, p = 0.011) in PLHIV and negatively correlated with patrolling monocytes (r = -0.36, p = 0.031) and tissue factor expression (r = -0.39, p = 0.017) in PWOH.

CONCLUSIONS

Our results suggest that HIV may be associated more with severity rather than the presence of CAD in Uganda. Sex differences in the HIV effect suggest that tailored CAD prevention strategies may be required in this setting.

Nature versus Number: Monocytes in Cardiovascular Disease

Monocytes play a key role in cardiovascular disease (CVD) as their influx into the vessel wall is necessary for the development of an atherosclerotic plaque. Monocytes are, however, heterogeneous differentiating from classical monocytes through the intermediate subset to the nonclassical subset. While it is recognized that the percentage of intermediate and nonclassical monocytes are higher in individuals with CVD, accompanying changes in inflammatory markers suggest a functional impact on disease development that goes beyond the increased proportion of these ‘inflammatory’ monocyte subsets. Furthermore, emerging evidence indicates that changes in monocyte proportion and function arise in dyslipidemia, with lipid lowering medication having some effect on reversing these changes. This review explores the nature and number of monocyte subsets in CVD addressing what they are, when they arise, the effect of lipid lowering treatment, and the possible implications for plaque development. Understanding these associations will deepen our understanding of the clinical significance of monocytes in CVD.

Role of Brain Arterial Remodeling in HIV-Associated Cerebrovascular Outcomes

As the life expectancy of people living with HIV (PLWH) on combination antiretroviral therapy (cART) increases, so does morbidity from cerebrovascular disease and neurocognitive disorders. Brain arterial remodeling stands out as a novel investigational target to understand the role of HIV in cerebrovascular and neurocognitive outcomes. We therefore conducted a review of publications in PubMed, EMBASE, Web of Science and Wiley Online Library, from inception to April 2021. We included search terms such as HIV, cART, brain, neuroimmunity, arterial remodeling, cerebrovascular disease, and neurocognitive disorders. The literature shows that, in the post-cART era, PLWH continue to experience an increased risk of stroke and neurocognitive disorders (albeit milder forms) compared to uninfected populations. PLWH who are immunosuppressed have a higher proportion of hemorrhagic strokes and strokes caused by opportunistic infection and HIV vasculopathy, while PLWH on long-term cART have higher rates of ischemic strokes, compared to HIV-seronegative controls. Brain large artery atherosclerosis in PLWH is associated with lower CD4 nadir and higher CD4 count during the stroke event. HIV vasculopathy, a form of non-atherosclerotic outward remodeling, on the other hand, is associated with protracted immunosuppression. HIV vasculopathy was also linked to a thinner media layer and increased adventitial macrophages, suggestive of non-atherosclerotic degeneration of the brain arterial wall in the setting of chronic central nervous system inflammation. Cerebrovascular architecture seems to be differentially affected by HIV infection in successfully treated versus immunosuppressed PLWH. Brain large artery atherosclerosis is prevalent even with long-term immune reconstitution post-cART. HIV-associated changes in brain arterial walls may also relate to higher rates of HIV-associated neurocognitive disorders, although milder forms are more prevalent in the post-cART era. The underlying mechanisms of HIV-associated pathological arterial remodeling remain poorly understood, but a role has been proposed for chronic HIV-associated inflammation with increased burden on the vasculature. Neuroimaging may come to play a role in assessing brain arterial remodeling and stratifying cerebrovascular risk, but the data remains inconclusive. An improved understanding of the different phenotypes of brain arterial remodeling associated with HIV may reveal opportunities to reduce rates of cerebrovascular disease in the aging population of PLWH on cART.

Utilization of absolute monocyte counts to predict cardiovascular events in people living with HIV

OBJECTIVES

Cardiovascular risk is increased in people living with HIV (PLWH). In HIV-uninfected populations, total absolute monocyte count (AMC) has been shown to be predictive of future cardiovascular events (CVEs). We sought to determine whether AMC predicts CVEs in PLWH independent of established and HIV-related cardiovascular risk factors.

METHODS

We identified all PLWH within the Partners HIV Cohort without factors that could confound the monocyte count. CVE was defined as fatal or non-fatal acute myocardial infarction or ischaemic stroke. Baseline-measured AMC was defined as the average of all outpatient AMC counts a year before and after the baseline date. Multivariable Cox proportional hazards models were used to assess the association of baseline AMC with CVEs.

RESULTS

Our cohort consisted of 1980 patients, with median follow-up of 10.9 years and 182 CVEs. Mean (± SD) age was 41.9 ± 9.3 years; 73.0% were male. Mean CD4 count was 506.3 ± 307.1 cells/µL, 48% had HIV viral load (VL) < 400 copies/mL, and 87% were on antiretroviral therapy. Mean AMC was 0.38 × 10³  ± 0.13 cells/µL. In multivariable modelling adjusted for traditional CV risk factors, CD4 cell count, and HIV VL, AMC quartile 2 (Q2) (HR = 1.01, P = 0.98), Q3 (HR = 1.07, P = 0.76), and Q4 (HR = 0.97, P = 0.89) were not significantly predictive of CVE compared with Q1.

DISCUSSION

Baseline AMC was not associated with long-term CVEs in PLWH. AMC obtained in routine clinical encounters does not appear to enhance CV risk stratification in PLWH.

Short Communication: Carotid Artery Plaque Burden in HIV Is Associated with Soluble Mediators and Monocytes

Maximum carotid plaque thickness (MCPT) measures the largest plaque thickness in the carotid artery and reflects atherosclerosis plaque burden. MCPT may be a better predictor of cardiovascular disease than carotid artery intima-media thickness (cIMT) because it identifies potential unstable arterial atherosclerosis plaques. We assessed the relationships of monocyte and T cell populations and plasma soluble mediators with MCPT measures. We performed a cross-sectional and small follow-up analysis in people living with HIV (PLWH) aged >40 years on stable antiretroviral therapy (ART) >6 months. MCPT was acquired by high-resolution B-mode ultrasound. Existing monocyte subsets and T cell activation frequencies were determined by flow cytometry and plasma mediators of inflammation and apolipoproteins were measured by Luminex assay. One hundred twenty-five ART-treated PLWH, 88% male, 55% Caucasian, with a median age of 51 years, median CD4 count of 477 cells/μL (Q1: 325, Q3: 612), 84% undetectable plasma HIV RNA (<50 copies/mL). Twenty-five PLWH had detectable carotid plaque. MCPT correlated with monocyte chemoattractant protein-1 (MCP-1; r = 0.487, p = .016), tumor necrosis factor-α (TNF-α; r = 0.474 p = .019), soluble vascular cell adhesion molecule-1 (sVCAM-1; r = 0.472, p = .020), apolipoprotein B6 (ApoB6; r = -0.473, p = .019), and interleukin-6 (IL-6; r = 0.455, p = .025). In a multivariable regression model, MCP-1, TNF-α, and sVCAM-1 remained significant after adjustment for age. Carotid plaque burden was associated with increased inflammatory, monocyte, and endothelial measures, including MCP-1, TNF-α, and sVCAM-1 levels. Further investigation on the evolution or severity of plaque burden in this population is warranted.

Single-Cell Immune Profiling in Coronary Artery Disease: The Role of State-of-the-Art Immunophenotyping With Mass Cytometry in the Diagnosis of Atherosclerosis

Coronary artery disease remains the leading cause of death globally and is a major burden to every health system in the world. There have been significant improvements in risk modification, treatments, and mortality; however, our ability to detect asymptomatic disease for early intervention remains limited. Recent discoveries regarding the inflammatory nature of atherosclerosis have prompted investigation into new methods of diagnosis and treatment of coronary artery disease. This article reviews some of the highlights of the important developments in cardioimmunology and summarizes the clinical evidence linking the immune system and atherosclerosis. It provides an overview of the major serological biomarkers that have been associated with atherosclerosis, noting the limitations of these markers attributable to low specificity, and then contrasts these serological markers with the circulating immune cell subtypes that have been found to be altered in coronary artery disease. This review then outlines the technique of mass cytometry and its ability to provide high-dimensional single-cell data and explores how this high-resolution quantification of specific immune cell subpopulations may assist in the diagnosis of early atherosclerosis in combination with other complimentary techniques such as single-cell RNA sequencing. We propose that this improved specificity has the potential to transform the detection of coronary artery disease in its early phases, facilitating targeted preventative approaches in the precision medicine era.

Enhancing care for people living with HIV: current and future monitoring approaches

INTRODUCTION

Antiretroviral therapy (ART) is the most significant advance in the medical management of HIV-1 infection. Given the fact that HIV cannot be eradicated from the body, ART has to be indefinitely maintained. New approaches need to be defined for monitoring HIV-infected individuals (PLWHIV), including clinical, virologic, immunological parameters and also ways to collect individual points of view and quality of life.

AREAS COVERED

We discuss which tests may be used to improve the management of PLWHIV and respond to a comprehensive health demand.

EXPERT OPINION

Viral load and CD4 counts are well-validated outcome measures and we still need them, but they do not completely depict the health status of PLWHIV. We need to better understand and to apply to clinical practice what happens in sanctuaries, what is the role of HIV DNA, what is the meaning of low-level viremia. Most of these questions do not yet have a definitive response. Further, we need to understand how to modify these variables in order to improve outcomes.Similar points may be raised for immunological measures and for tests exploring the tolerability of drugs. The goal must be the evolution from a viro/immunologic-based to a comprehensive quality-of-health-based evaluation of PLWHIV.

Plasma tissue factor and immune activation are associated with carotid intima-media thickness progression in treated HIV infection

OBJECTIVES

We evaluated the roles of biomarkers of immune activation with carotid intima-media thickness (CIMT) progression in treated HIV infection.

DESIGN

Longitudinal observational study of 118 treated and virologically suppressed individuals.

METHODS

We measured biomarkers of immune activation at baseline using cryopreserved samples. CIMT was measured at baseline and longitudinally using high-resolution ultrasound. Linear regression was used to estimate biomarker associations with CIMT progression, and logistic regression was used to model plaque progression.

RESULTS

The median duration of follow-up was 2.0 years. The median annual rate of change in mean CIMT was 6.0%. Rates of progression were more rapid in the bifurcation (5.6%/year, P = 0.006) and internal (6.5%/year, P = 0.0008) than common CIMT (4.3%/year). Incident plaque occurred in 13 of the 52 individuals without baseline plaque. In multivariable adjusted analysis, plasma tissue factor and monocyte chemoattractant protein-1 were associated with more rapid common CIMT progression (0.058 mm/year, P = 0.0004 and 0.067 mm/year, P = 0.017; all estimates per doubling). CD8 T-cell count and percentage of HLA-DRCD38CD8 T cells were associated with more rapid internal CIMT progression (0.10 mm/year, P = 0.008 and 0.054 mm/year, P = 0.045). CD8 T-cell count was also associated with 0.068 mm/year more rapid mean CIMT progression (P = 0.011). Each 10% increase in CD4 T-cell count at baseline was associated with a 34% reduced odds of plaque progression (P = 0.018).

CONCLUSION

Residual immune activation and plasma tissue factor are independently associated with CIMT progression in treated HIV infection. Interventions targeting coagulation and inflammatory pathways to reduce cardiovascular disease risk in HIV merit additional investigations.

HIV-1 Tat: Role in Bystander Toxicity

HIV Tat protein is a critical protein that plays multiple roles in HIV pathogenesis. While its role as the transactivator of HIV transcription is well-established, other non-viral replication-associated functions have been described in several HIV-comorbidities even in the current antiretroviral therapy (ART) era. HIV Tat protein is produced and released into the extracellular space from cells with active HIV replication or from latently HIV-infected cells into neighboring uninfected cells even in the absence of active HIV replication and viral production due to effective ART. Neighboring uninfected and HIV-infected cells can take up the released Tat resulting in the upregulation of inflammatory genes and activation of pathways that leads to cytotoxicity observed in several comorbidities such as HIV associated neurocognitive disorder (HAND), HIV associated cardiovascular impairment, and accelerated aging. Thus, understanding how Tat modulates host and viral response is important in designing novel therapeutic approaches to target the chronic inflammatory effects of soluble viral proteins in HIV infection.

Immune cell phenotyping in low blood volumes for assessment of cardiovascular disease risk, development, and progression: a pilot study

Background

Cardiovascular disease (CVD) is the leading cause of death in the world. Given the role of immune cells in atherosclerosis development and progression, effective methods for characterizing immune cell populations are needed, particularly among populations disproportionately at risk for CVD.

Results

By using a variety of antibodies combined in one staining protocol, we were able to identify granulocyte, lymphocyte, and monocyte sub-populations by CD-antigen expression from 500 µl of whole blood, enabling a more extensive comparison than what is possible with a complete blood count and differential (CBC). The flow cytometry panel was established and tested in a total of 29 healthy men and women. As a proof of principle, these 29 samples were split by their race/ethnicity: African-Americans (AA) (N = 14) and Caucasians (N = 15). We found in accordance with the literature that AA had fewer granulocytes and more lymphocytes when compared to Caucasians, though the proportion of total monocytes was similar in both groups. Several new differences between AA and Caucasians were noted that had not been previously described. For example, AA had a greater proportion of platelet adhesion on non-classical monocytes when compared to Caucasians, a cell-to-cell interaction described as crucially important in CVD. We also examined our flow panel in a clinical population of AA women with known CVD risk factors (N = 20). Several of the flow cytometry parameters that cannot be measured with the CBC displayed correlations with clinical CVD risk markers. For instance, Framingham Risk Score (FRS) calculated for each participant correlated with immune cell platelet aggregates (PA) (e.g. T cell PA β = 0.59, p = 0.03 or non-classical monocyte PA β = 0.54, p = 0.02) after adjustment for body mass index (BMI).

Conclusion

A flow cytometry panel identified differences in granulocytes, monocytes, and lymphocytes between AA and Caucasians which may contribute to increased CVD risk in AA. Moreover, this flow panel identifies immune cell sub-populations and platelet aggregates associated with CVD risk. This flow cytometry panel may serve as an effective method for phenotyping immune cell populations involved in the development and progression of CVD.

Evidence for Persistent Monocyte and Immune Dysregulation After Prolonged Viral Suppression Despite Normalization of Monocyte Subsets, sCD14 and sCD163 in HIV-Infected Individuals

BACKGROUND

People living with HIV on antiretroviral therapy (HIV/ART) experience excess non-AIDS comorbidities, and also remain at increased risk for certain infections and viral malignancies. Monocytes/macrophages are central to many of these comorbidities, and elevated plasma cytokines and immune activation during untreated infection are often incompletely reversed by ART and are also associated with comorbidities.

METHODS

We investigated monocyte surface markers, gene expression, and plasma cytokines in 11 HIV-infected older individuals (median 53 years) who started therapy with low CD4 counts (median 129 cells/µl), with elevated hsCRP (≥ 2mg/L) despite long-term ART (median 7.4 years), along with matched controls.

RESULTS

Frequency of monocyte subsets (based on CD14/CD16/CD163), were not different from controls, but surface expression of CD163 was increased (P = 0.021) while PD1 was decreased (P = 0.013) along with a trend for higher tissue factor (P = 0.096). As a group, HIV/ART participants had elevated plasma CCL2 (MCP-1; P = 0.0001), CXCL9 (MIG; P = 0.04), and sIL2R (P = 0.015), which were correlated, while sCD14 was not elevated. Principal component analysis of soluble markers revealed that 6/11 HIV/ART participants clustered with controls, while 5 formed a distinct group, driven by IL-10, CCL11, CXCL10, CCL2, CXCL9, and sIL2R. These individuals were significantly older than those clustering with controls. Transcriptomic analysis revealed multiple genes linked to immune functions including inflammation, immune cell development, and cell-cell signaling that were downregulated in HIV/ART monocytes and distinct from patterns in untreated subjects.

CONCLUSIONS

Long-term ART-treated individuals normalize monocyte subsets but exhibit immune dysregulation involving both aberrant inflammation and monocyte dysfunction, as well as inter-individual heterogeneity, suggesting complex mechanisms linking monocytes and HIV/ART comorbidities.

Inflammatory biomarker levels over 48 weeks with dual vs triple lopinavir/ritonavir-based therapy: Substudy of a randomized trial

Background

Inflammation has been associated with increased morbidity and mortality in HIV-positive patients. We compared inflammatory biomarkers with dual therapy using lopinavir/ritonavir plus lamivudine (LPV/r+3TC) versus triple therapy using LPV/r plus two nucleoside reverse transcriptase inhibitors (LPV/r+2NRTIs) in treatment-naïve HIV-positive adults.

Methods

This was a substudy among Argentinian participants in the randomized trial GARDEL. We measured hsCRP, IL-6, MCP-1, TNF, D-dimer and sCD14 from plasma collected at baseline, week 24 and week 48. Generalized estimating equations with an identity/logit link were used to model the average impact of dual versus triple therapy on each biomarker over time, controlling for baseline levels. Additional models estimated the average effect of virologic suppression on biomarker levels over time, adjusting for age, sex, and baseline CD4 count.

Results

Of 191 trial participants enrolled in Argentina, 172 had baseline and follow-up measurements and were included. Median (IQR) age was 35.5 (28.5, 45) years and CD4 cell count was 310 (219, 414) cells/mm³. Dual therapy was not associated with significantly different biomarker levels over 48 weeks relative to triple therapy. Virologic suppression was associated with statistically significant decreases in MCP-1, TNF and D-dimer levels and an unexpected increase in sCD14 levels. No change was observed in hsCRP or the proportion of participants with undetectable IL-6 levels.

Conclusions

In addition to having virologic non-inferiority, LPV/r+3TC dual therapy is generally associated with similar inflammatory biomarker levels over 48 weeks compared to LPV/r+2NRTIs triple therapy in treatment-naïve adults. Further study of dual treatment regimens is warranted.

Limited correlation between systemic biomarkers and neurocognitive performance before and during HIV treatment

The AIDS Clinical Trials Group (ACTG) study A5303 investigated the associations between neuropsychological performance (NP) and inflammatory biomarkers in HIV-infected participants. Fifteen NP tests were administered at baseline and week 48 to 233 ART naïve participants randomized to maraviroc- or tenofovir-containing ART. Neurocognition correlated modestly with markers of lymphocyte activation and inflammation pre-ART (percent CD38+/HLA-DR+(CD4+) (r = - 0.22, p = 0.02) and percent CD38+/HLA-DR+(CD8+) (r = - 0.25, p = 0.02)), and with some monocyte subsets during ART (r = 0.25, p = 0.02). Higher interleukin-6 and percent CD38+/HLA-DR+(CD8+) were independently associated with worse severity of HIV-associated neurocognitive disorders (HAND) (p = 0.04 and 0.01, respectively). More studies to identify HAND biomarkers are needed.

Inflammatory and immunometabolic consequences of gut dysfunction in HIV: Parallels with IBD and implications for reservoir persistence and non-AIDS comorbidities

The gastrointestinal mucosa is critical for maintaining the integrity and functions of the gut. Disruption of this barrier is a hallmark and a risk factor for many intestinal and chronic inflammatory diseases. Inflammatory bowel disease (IBD) and HIV infection are characterized by microbial translocation and systemic inflammation. Despite the clinical overlaps between HIV and IBD, significant differences exist such as the severity of gut damage and mechanisms of immune cell homeostasis. Studies have supported the role of metabolic activation of immune cells in promoting chronic inflammation in HIV and IBD. This inflammatory response persists in HIV+ persons even after long-term virologic suppression by antiretroviral therapy (ART). Here, we review gut dysfunction and microbiota changes during HIV infection and IBD, and discuss how this may induce metabolic reprogramming of monocytes, macrophages and T cells to impact disease outcomes. Drawing from parallels with IBD, we highlight how factors such as lipopolysaccharides, residual viral replication, and extracellular vesicles activate biochemical pathways that regulate immunometabolic processes essential for HIV persistence and non-AIDS metabolic comorbidities. This review highlights new mechanisms and support for the use of immunometabolic-based therapeutics towards HIV remission/cure, and treatment of metabolic diseases.

Continued Interest and Controversy: Vitamin D in HIV

PURPOSE OF REVIEW

Vitamin D (VitD) deficiency is highly prevalent among HIV-infected individuals. Given the overlapping risk for several chronic disease and immunomodulatory outcomes from both long-standing HIV and VitD deficiency, there is great interest in clarifying the clinical role of VitD for this population.

RECENT FINDINGS

Recent studies have expanded our knowledge regarding the epidemiology and mechanisms of VitD deficiency-associated outcomes in the setting of HIV. Clinical trials focusing on VitD supplementation have demonstrated a positive impact on bone mineral density in subgroups of HIV-infected individuals initiating ART or on suppressive ART regimens; however, significant heterogeneity exists between studies and data are less consistent with other clinical outcomes. Further research is needed to clarify uncertainly in several domains, including identifying patients at greatest risk for poor outcomes from VitD deficiency, standardizing definitions and measurement techniques, and better quantifying the benefits and risks of VitD supplementation across different demographic strata for skeletal and extra-skeletal outcomes.

Loss of CXCR4 on non-classical monocytes in participants of the Women's Interagency HIV Study (WIHS) with subclinical atherosclerosis

AIMS

To test whether human immunodeficiency virus (HIV) infection and subclinical cardiovascular disease (sCVD) are associated with expression of CXCR4 and other surface markers on classical, intermediate, and non-classical monocytes in women.

METHODS AND RESULTS

sCVD was defined as presence of atherosclerotic lesions in the carotid artery in 92 participants of the Women's Interagency HIV Study (WIHS). Participants were stratified into four sets (n = 23 each) by HIV and sCVD status (HIV-/sCVD-, HIV-/sCVD+, HIV+/sCVD-, and HIV+/sCVD+) matched by age, race/ethnicity, and smoking status. Three subsets of monocytes were determined from archived peripheral blood mononuclear cells. Flow cytometry was used to count and phenotype surface markers. We tested for differences by HIV and sCVD status accounting for multiple comparisons. We found no differences in monocyte subset size among the four groups. Expression of seven surface markers differed significantly across the three monocyte subsets. CXCR4 expression [median fluorescence intensity (MFI)] in non-classical monocytes was highest among HIV-/CVD- [628, interquartile range (IQR) (295-1389)], followed by HIV+/CVD- [486, IQR (248-699)], HIV-/CVD+ (398, IQR (89-901)), and lowest in HIV+/CVD+ women [226, IQR (73-519)), P = 0.006 in ANOVA. After accounting for multiple comparison (Tukey) the difference between HIV-/CVD- vs. HIV+/CVD+ remained significant with P = 0.005 (HIV-/CVD- vs. HIV+/CVD- P = 0.04, HIV-/CVD- vs. HIV-/CVD+ P = 0.06, HIV+/CVD+ vs. HIV+/CVD- P = 0.88, HIV+/CVD+ vs. HIV-/CVD+ P = 0.81, HIV+/CVD- vs. HIV-/CVD+, P = 0.99). All pairwise comparisons with HIV-/CVD- were individually significant (P = 0.050 vs. HIV-/CVD+, P = 0.028 vs. HIV+/CVD-, P = 0.009 vs. HIV+/CVD+). CXCR4 expression on non-classical monocytes was significantly higher in CVD- (501.5, IQR (249.5-887.3)) vs. CVD+ (297, IQR (81.75-626.8) individuals (P = 0.028, n = 46 per group). CXCR4 expression on non-classical monocytes significantly correlated with cardiovascular and HIV-related risk factors including systolic blood pressure, platelet and T cell counts along with duration of antiretroviral therapy (P < 0.05). In regression analyses, adjusted for education level, study site, and injection drug use, presence of HIV infection and sCVD remained significantly associated with lower CXCR4 expression on non-classical monocytes (P = 0.003), but did not differ in classical or intermediate monocytes.

CONCLUSION

CXCR4 expression in non-classical monocytes was significantly lower among women with both HIV infection and sCVD, suggesting a potential atheroprotective role of CXCR4 in non-classical monocytes.

T cell senescence predicts subclinical atherosclerosis in HIV-infected patients similarly to traditional cardiovascular risk factors

The main objective of this study is to evaluate the predictive capacity of T cell activation/senescence in subclinical atherosclerosis (SCA) in a group of HIV-infected patients. So, a cross-sectional analysis was performed on 91 long-term triple-ART therapy HIV-infected patients from an observational and prospective cohort. Carotid Intima Media Thickness (cIMT) was measured. Binary logistic regression was used to evaluate independent variables associated with SCA. Compared to patients without SCA, patients with SCA (60.4%) were older (41.33 ± 9.04 vs. 51.73 ± 8.44 years old, p < 0.001) and showed Framingham risk score (2.63 ± 3.127 vs. 7.66 ± 5.84, p = 0.008), as well as higher numbers of CD4⁺CD8⁺ double positive T cells (0.50 ± 0.42% vs. 0.81 ± 0.79%, p = 0.037), CD8⁺CD28^- T cells (41.70 ± 16.96% vs. 50.22 ± 16.15%, p = 0.018), higher expression of CD28 on CD8⁺CD28⁺ T cells (1865 ± 789 vs. 2243 ± 917 MFI, P = 0.046). In contrast, they showed lower expression of CD38 on CD19⁺ B cells (65.38 ± 27.47% vs. 42.67 ± 30.26%, P < 0.001). Logistic multivariable analysis showed that Framingham risk score >10% (OR = 14.84, CI95% 1.63-125; p = 0.016) and numbers of CD8⁺CD28^- T cells (OR = 1.032, CI 95% 1-1.065; p = 0.045) were independent factors associated with SCA. Patients with CD8⁺CD28^- T cells ≥59% compared to those <59% had higher risk of SCA (OR = 4, CI95% 1.19-13.3, p = 0.024). Interestingly, 27.4% of patients with low Framingham risk score had elevated levels of CD8⁺CD28^- T cells. In conclusion, immune senescence represented by accumulation of CD8⁺CD28^- T cells may contribute to improve the predictive capacity of the Framingham risk score, especially when the scores are low and can explain, at least in part, the higher prevalence of SCA observed in long-term ART-treated stable HIV infected patients.

Diastolic Dysfunction in Individuals With Human Immunodeficiency Virus Infection: Literature Review, Rationale and Design of the Characterizing Heart Function on Antiretroviral Therapy (CHART) Study

Antiretroviral therapy (ART) has been associated with a shift in the epidemiology of human immunodeficiency virus (HIV)-associated cardiomyopathy from a phenotype of primarily left ventricular (LV) systolic dysfunction to LV diastolic dysfunction (DD). Patients with HIV receiving ART have higher rates of DD compared with age-matched control subjects and develop DD at a younger age. However, little is known about the natural history and pathogenesis of DD in virally suppressed HIV-infected patients. Current evidence suggests that immune processes modulate the risk for cardiac involvement in HIV-infected persons. Ongoing inflammation appears to have myocardial effects, and accelerated myocardial fibrosis appears to be a key mediator of HIV-induced DD. The Characterizing Heart Function on Antiretroviral Therapy (CHART) study aims to systematically investigate determinants, mechanisms, and consequences of DD in HIV-infected patients. We will compare ART-treated virally suppressed HIV-infected individuals with and without DD and HIV- individuals with DD regarding (1) systemic inflammation, myocardial stress, and subclinical myocardial necrosis as indicated by circulating biomarkers; (2) immune system activation as indicated by cell surface receptors; (3) myocardial fibrosis according to cardiac magnetic resonance examination; (4) markers of fibrosis and remodeling, oxidative stress, and hypercoagulability; (5) left atrial function according to echocardiographic examination; (6) myocardial stress and subclinical necrosis as indicated by circulating biomarkers; (7) proteomic and metabolic profiles; and (8) phenotype signatures derived from clinical, biomarker, and imaging data.

Ageing with HIV

The population of people living with HIV (PLWH) is growing older with an estimated 4 million over the age of 50 years, a figure which has doubled since the introduction of effective antiretroviral therapy (ART) and which is increasing globally. Despite effective ART, PLWH still experience excess morbidity and mortality compared to the general population with increased prevalence of age-related, non-AIDS illnesses (NAI) such as cardiovascular disease, malignancies, cognitive impairment and reduced bone mineral density, which impact disability and everyday functioning. This review will discuss the challenges presented by comorbidities in ageing PLWH and discuss the aetiology and management of age-related illnesses in this vulnerable population.

HIV infection and stroke

The landscape of human immunodeficiency virus (HIV) infection is changing with the increasing coverage of antiretroviral therapy (ART). Patients are living longer but continually exposed to a virologically suppressed HIV infection. This has resulted in a decrease in acquired immune deficiency syndrome (AIDS)-related complications such as opportunistic infections, and an increase in non-AIDS complications such as stroke. In this era, stroke is perhaps the most important neurologic complication of HIV infection. Furthermore, stroke is more of a heterogeneous disease in people living with HIV infection and therefore needs to be approached systematically. Many of the etiologies are treatable. HIV-associated vasculopathy is perhaps the most common etiology in this population and our understanding of this is still evolving. Moreover, the treatment of HIV infection may contribute to an excess risk of stroke and interact with stroke therapies.

Nucleoside/nucleotide reverse transcriptase inhibitors attenuate angiogenesis and lymphangiogenesis by impairing receptor tyrosine kinases signalling in endothelial cells

BACKGROUND AND PURPOSE

Cardiovascular disease associated with antiretroviral therapy (ART) has become a major clinical challenge for HIV-positive patients. However, the role of ART in blood vessel growth is largely unknown. Here, we examined an integral component of ART, nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and investigated their effects on key microvascular functions, including angiogenesis and lymphangiogenesis.

EXPERIMENTAL APPROACH

The angiogenesis/lymphangiogenesis capability of endothelial cells (ECs) was evaluated using migration, proliferation and tube formation assays in vitro, and mouse ear and Matrigel plug assays in vivo. Expressions of signalling molecules and mitochondrial antioxidant catalases were determined using Western blotting. Receptor tyrosine kinase (RTK) internalization and endocytosis were examined using flow cytometry and confocal immunofluorescence microscopy respectively. Mitochondrial DNA copy number and ROS were determined using quantitative real-time PCR and MitoSOX staining respectively.

KEY RESULTS

Pharmaceutical doses of NRTIs [azidothymidine (AZT), tenofovir disoproxil fumarate (TDF) and lamivudine (3TC)] inhibited angiogenesis and lymphangiogenesis both in vivo and in vitro by affecting the proliferation and migration of ECs. Correspondingly, NRTIs selectively attenuated the activation and transduction of endothelial RTK signals, VEGFR2 and FGFR1 pathways, in vascular ECs and the VEGFR3 pathway in lymphatic ECs. Both TDF and 3TC restrained RTKs' endocytosis into early endosomes but not internalization, while AZT blocked the protein maturation of RTKs. Excessive ROS levels were detected in NRTI-treated ECs, and the MnSOD mimic MnTMPyP alleviated the angiogenic/lymphangiogenic defects induced by NRTIs.

CONCLUSIONS AND IMPLICATIONS

NRTIs negatively regulate angiogenesis and lymphangiogenesis by inducing mitochondrial oxidative stress and subsequently impairing RTK signalling in ECs.

LINKED ARTICLES

This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.

HIV-1-Associated Atherosclerosis: Unraveling the Missing Link

Cardiovascular disease, including atherosclerosis and atherosclerosis-associated complications, is an increasing cause of morbidity and mortality in human immunodeficiency virus (HIV) patients in the post-antiretroviral therapy era. HIV alone accelerates atherosclerosis. Antiretroviral therapy; HIV-associated comorbidities, such as dyslipidemia, drug abuse, and opportunistic infections; and lifestyle are risk factors for HIV-associated atherosclerosis. However, our current understanding of HIV-associated atherogenesis is very limited and has largely been obtained from clinical observation. There is a pressing need to experimentally unravel the missing link between HIV and atherosclerosis. Understanding these mechanisms will help to better develop and design novel therapeutic interventions for the treatment of HIV-associated cardiovascular disease. HIV mainly infects T cells and macrophages resulting in the induction of oxidative and endoplasmic reticulum stress, the formation of the inflammasome, and the dysregulation of autophagy. These mechanisms may contribute to HIV-associated atherogenesis. In this review, we will summarize our current understanding and propose potential mechanisms of HIV-associated atherosclerosis.

Association of Arterial and Lymph Node Inflammation With Distinct Inflammatory Pathways in Human Immunodeficiency Virus Infection

Importance

Human immunodeficiency virus (HIV) infection is associated with a high risk of cardiovascular disease and increased arterial inflammation. In HIV, inflammation is also increased within lymph nodes (LNs), tissues known to harbor the virus even among treated and suppressed individuals.

Objective

To test the hypothesis that arterial inflammation is linked to HIV disease activity and to inflammation within HIV-infected tissues (LNs).

Design, Setting, and Participants

For this case-control study, participants were recruited from the SCOPE (Observational Study of the Consequences of the Protease Inhibitor Era) cohort, a clinic-based cohort of individuals receiving care at San Francisco General Hospital and the San Francisco Veteran's Affairs Medical Center. Arterial and LN inflammation were measured using 18F-fluorodeoxyglucose positron emission tomography. Detailed immunophenotyping was performed, along with measurement of viral activity/persistence and of circulating inflammatory biomarkers.

Main Outcomes and Measures

Arterial and LN inflammation.

Results

A total of 74 men were studied (45 HIV-infected men with a median age of 53 years [interquartile range, 49-59 years] and 29 uninfected male controls with a median age of 52 years [interquartile range, 46-56 years]). Lymph node inflammation was higher in HIV-infected individuals and correlated with markers of viral disease activity (viral load, CD8+ T cells, and CD4/CD8 ratio) and CD4+ T-cell activation. Uninfected controls had the lowest LN activity (mean [SD] maximum axillary LN standardized uptake value, 1.53 [0.56]), the elite controller and ART-suppressed groups had intermediate levels of LN (mean [SD] maximum axillary LN standardized uptake value, 2.12 [0.87] and 2.32 [1.79], respectively), and the noncontrollers had the highest activity (mean [SD] maximum axillary LN standardized uptake value, 8.82 [3.08]). Arterial inflammation was modestly increased in HIV-infected individuals and was positively correlated with circulating inflammatory biomarkers (high-sensitivity C-reactive protein and IL-6) and activated monocytes (CD14dimCD16+; nonclassical) but not with markers of HIV. While LN and arterial inflammation were increased in HIV, inflammatory activity in these tissues was not related (r = 0.09, P = .56).

Conclusions and Relevance

While LNs and, to a lesser degree, the arterial wall are inflamed in HIV, inflammation in these tissues is not closely linked. Namely, measures of HIV disease activity are strongly associated with LN inflammation but not with arterial inflammation. These data suggest that LN and arterial inflammation do not share underlying pathways of immune activation and also that therapeutic interventions that reduce viral disease activity may not predictably reduce arterial inflammation in HIV or its downstream consequence (ie, cardiovascular disease).

Increased glucose transporter-1 expression on intermediate monocytes from HIV-infected women with subclinical cardiovascular disease

OBJECTIVE

People living with HIV (PLWH) have chronic immune activation and increased cardiovascular disease (CVD) risk. Activation of monocytes and T lymphocytes causes upregulation of glucose transporter-1 (GLUT1) for efficient function. PLWH have an increased percentage of GLUT1-expressing monocytes and T lymphocytes, but it is unclear if these cells are associated with CVD. We evaluated the expression of GLUT1 and CD38 on monocyte and T lymphocyte populations from HIV-infected women with subclinical CVD.

METHODS

Participants with more than 75th percentile (n = 15) and less than 25th percentile (n = 15) age-adjusted intima-media thickness (IMT) at the right common carotid artery and bifurcation were identified from the Women's Interagency HIV Study. Groups were matched by age, race/ethnicity, smoking status, and CD4 cell count. All women were receiving suppressive antiretroviral therapy except for one high and one low IMT participant. Monocyte and T lymphocyte populations were evaluated for GLUT1 and CD38 expression using flow cytometry.

RESULTS

Intermediate monocytes from high IMT women had significantly increased expression of GLUT1 (310 MFI vs. 210 MFI, P = 0.024) (66.4% vs. 48.5%, P = 0.031) and CD38 (339 MFI vs. 211 MFI, P = 0.002) (10.5% vs. 3.8%, P = 0.0002) compared with women with low IMT. High and low IMT participants showed no differences in GLUT1 or CD38 expression on classical monocytes, nonclassical monocytes, CD4 and CD8 T lymphocytes.

CONCLUSION

GLUT1-expressing intermediate monocytes are elevated in HIV-infected women with subclinical CVD. These cells may contribute to development of CVD in PLWH and could be a novel target to limit inflammation.

A curated compendium of monocyte transcriptome datasets of relevance to human monocyte immunobiology research

Systems-scale profiling approaches have become widely used in translational research settings. The resulting accumulation of large-scale datasets in public repositories represents a critical opportunity to promote insight and foster knowledge discovery. However, resources that can serve as an interface between biomedical researchers and such vast and heterogeneous dataset collections are needed in order to fulfill this potential. Recently, we have developed an interactive data browsing and visualization web application, the Gene Expression Browser (GXB). This tool can be used to overlay deep molecular phenotyping data with rich contextual information about analytes, samples and studies along with ancillary clinical or immunological profiling data. In this note, we describe a curated compendium of 93 public datasets generated in the context of human monocyte immunological studies, representing a total of 4,516 transcriptome profiles. Datasets were uploaded to an instance of GXB along with study description and sample annotations. Study samples were arranged in different groups. Ranked gene lists were generated based on relevant group comparisons. This resource is publicly available online at http://monocyte.gxbsidra.org/dm3/landing.gsp.