Shared monocyte subset phenotypes in HIV-1 infection and in uninfected subjects with acute coronary syndrome. Blood. 2012;120:4599-4608. [PMID: 23065151 DOI: 10.1182/blood-2012-05-433946]

Pathophysiology and management of cardiovascular disease in patients with HIV

Results from several studies have suggested that people with HIV have an increased risk of cardiovascular disease, especially coronary heart disease, compared with people not infected with HIV. People living with HIV have an increased prevalence of traditional cardiovascular disease risk factors, and HIV-specific mechanisms such as immune activation. Although older, more metabolically harmful antiretroviral regimens probably contributed to the risk of cardiovascular disease, new data suggest that early and continuous use of modern regimens, which might have fewer metabolic effects, minimises the risk of myocardial infarction by maintaining viral suppression and decreasing immune activation. Even with antiretroviral therapy, however, immune activation persists in people with HIV and could contribute to accelerated atherosclerosis, especially of coronary lesions that are susceptible to rupture. Therefore, treatments that safely reduce inflammation in people with HIV could provide additional cardiovascular protection alongside treatment of both traditional and non-traditional risk factors.

Plasma CXCL10, sCD163 and sCD14 Levels Have Distinct Associations with Antiretroviral Treatment and Cardiovascular Disease Risk Factors

We investigate the associations of three established plasma biomarkers in the context of HIV and treatment-related variables including a comprehensive cardiovascular disease risk assessment, within a large ambulatory HIV cohort. Patients were recruited in 2010 to form the Royal Perth Hospital HIV/CVD risk cohort. Plasma sCD14, sCD163 and CXCL10 levels were measured in 475 consecutive patients with documented CVD risk (age, ethnicity, gender, smoking, blood pressure, BMI, fasting metabolic profile) and HIV treatment history including immunological/virological outcomes. The biomarkers assessed showed distinct associations with virological response: CXCL10 strongly correlated with HIV-1 RNA (p<0.001), sCD163 was significantly reduced among 'aviraemic' patients only (p = 0.02), while sCD14 was unaffected by virological status under 10,000 copies/mL (p>0.2). Associations between higher sCD163 and protease inhibitor therapy (p = 0.05) and lower sCD14 with integrase inhibitor therapy (p = 0.02) were observed. Levels of sCD163 were also associated with CVD risk factors (age, ethnicity, HDL, BMI), with a favourable influence of Framingham score <10% (p = 0.04). Soluble CD14 levels were higher among smokers (p = 0.002), with no effect of other CVD risk factors, except age (p = 0.045). Our findings confirm CXCL10, sCD163 and sCD14 have distinct associations with different aspects of HIV infection and treatment. Levels of CXCL10 correlated with routinely monitored variables, sCD163 levels reflect a deeper level of virological suppression and influence of CVD risk factors, while sCD14 levels were not associated with routinely monitored variables, with evidence of specific effects of smoking and integrase inhibitor therapy warranting further investigation.

Inflammation, immune activation, and cardiovascular disease in HIV

Cardiovascular disease is one of the leading causes of morbidity and mortality in people living with HIV. Several epidemiological studies have shown an increased risk of myocardial infarction and stroke compared to uninfected controls. Although traditional risk factors contribute to this increased risk of cardiovascular disease, HIV-specific mechanisms likely also play a role. Systemic inflammation has been linked to cardiovascular disease in several populations suffering from chronic inflammation, including people living with HIV. Although antiretroviral therapy reduces immune activation, levels of inflammatory markers remain elevated compared to uninfected controls. The causes of this sustained immune response are likely multifactorial and incompletely understood. In this review, we summarize the evidence describing the relationship between inflammation and cardiovascular disease and discuss potential anti-inflammatory treatment options for cardiometabolic disease in people living with HIV.

Maraviroc Intensification Improves Endothelial Function in Abacavir-Treated Patients, an Open-Label Randomized Cross-Over Pilot Study

Background

The increased risk of abacavir in cardiovascular disease (CVD) in HIV-infected patients is still being debated. Maraviroc, a CCR5 blocker, has been shown to decrease immune activation and monocyte infiltration in atherosclerotic plaques in murine experiments. Therefore, we examined the effect of maraviroc intensification on flow-mediated dilatation (FMD) in abacavir-treated HIV-infected patients and its effect on immunological and inflammatory parameters.

Methods

A open-label prospective crossover study with a duration of 16 weeks: 8 weeks of intervention (maraviroc intensification) and 8 weeks of control (unchanged cART regimen). FMD, HIV-specific variables, expression of HIV co-receptors, markers of inflammation and coagulation and cellular markers of immune activation were measured at weeks 0, 8 and 16. The changes (Δ) in these variables were compared between intervention and control periods using non-parametric tests. To evaluate the relation with the change in FMD, linear regression modeling was used.

Results

Twenty-one male patients with suppressed plasma HIV-RNA, on cART, had a known HIV infection for 9.2 years (IQR 6.9–13.5) with abacavir use for 6.5 years (2.8–9.3). A significantly increased FMD of 0.73% (IQR −0.25 to 1.70) was seen after maraviroc intensification compared to a decrease of −0.42% (IQR −1.89 to 0.25; p = 0.049) in the control period. There was a negative relation between ΔFMD with ΔD-dimer (β −22.70, 95% CI −39.27; −6.13, p = 0.011) and ΔCD95+ CD4+ T cells (β −0.16, 95% CI −0.28; −0.04, p = 0.013), adjusted for age and duration of HIV.

Conclusion

Maraviroc intensification modestly improves endothelial function in HIV-infected patients on an abacavir-containing regimen.

Trial registration

NCT01389063.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-016-0115-0) contains supplementary material, which is available to authorized users.

The role of statins in the setting of HIV infection

HIV-infected individuals are at an increased risk of cardiovascular disease (CVD) and other HIV-related co-morbidities. This is due in part to dyslipidemia associated with antiretroviral therapy and increased inflammation and immune activation from chronic HIV infection. Statins not only have potent lipid-lowering properties but are also anti-inflammatory and immunomodulators. Studies suggest that statin therapy in the HIV-infected population may decrease the risk of CVD and other non-AIDS-defining co-morbidities. This review summarizes the recent literature on statin use in the HIV setting.

Non-classical monocytes predict progression of carotid artery bifurcation intima-media thickness in HIV-infected individuals on stable antiretroviral therapy

BACKGROUND

Inflammation may contribute to cardiovascular disease (CVD) among antiretrovirally suppressed HIV-infected individuals. We assessed relationships of monocyte, CD8 T-cell activation and plasma biomarkers to changes in carotid artery intima-media thickness (CIMT).

METHODS

Longitudinal study of HIV-infected subjects ≥40 years and on stable antiretroviral therapy (ART) ≥3 months. Peripheral blood mononuclear cells were immunophenotyped by multiparameteric flow cytometry to quantify classical (CD14(++)CD16(-)), intermediate (CD14(++)CD16(+)), non-classical (CD14(low/+)CD16(++)) and transitional (CD14(+)CD16(-)) monocyte subsets and activated (CD38(+)HLA-DR(+)) CD8(+) T-cells at baseline. Plasma biomarkers were assessed by multiplex Luminex assay. High-resolution B-mode ultrasounds of right carotid arteries were obtained. Changes in CIMT over two years at the right common carotid artery (CIMTCCA) and right bifurcation (CIMTBIF) were outcome variables.

RESULTS

We studied 50 subjects: 84% male, median age 49 (Q1, Q3; 46, 56) years, median CD4 count 461 (317, 578) cells/mm(3), and with HIV RNA ≤ 50 copies/mL in 84%. Change in CIMTBIF correlated with log values of baseline absolute count of non-classical monocytes (r = 0.37, p = 0.020), and with MCP-1 (r = 0.42, p = 0.0024) and TNF-α (r = 0.30, p = 0.036) levels. In multivariable linear regression, only non-classical monocytes and MCP-1 predicted the change in CIMTBIF, independent of Framingham Risk Score and baseline CIMTBIF. No correlation was noted between CD8 T-cell activation and CIMTBIF change. Monocyte subsets, CD8 T-cell activation, and biomarker concentrations were not correlated with changes in CIMTCCA.

CONCLUSIONS

Our findings highlight the role of non-classical monocytes and MCP-1 in the progression of CIMTBIF in HIV-infected individuals on stable ART independent of traditional cardio-metabolic risk factors.

Elevation of Non-Classical (CD14+/lowCD16++) Monocytes Is Associated with Increased Albuminuria and Urine TGF-β1 in HIV-Infected Individuals on Stable Antiretroviral Therapy

OBJECTIVE

High rates of albuminuria are observed among HIV-infected individuals on stable antiretroviral therapy (ART). Though pro-inflammatory and pro-fibrotic responses are described as components of albuminuria in the general population, it is unclear how these responses are associated to albuminuria in ART-treated chronic HIV. We investigated the relationship of monocyte subsets and urine inflammatory and fibrotic biomarkers to albuminuria in ART-treated HIV-infected participants.

DESIGN AND METHODS

Cross-sectional analyses were performed on Hawaii Aging with HIV-cardiovascular disease study cohort participants who were required at entry to be ≥40 years old and on ART ≥3 months. Monocyte subpopulations were determined in banked peripheral blood mononuclear cells (PBMC) using multi-parametric flow-cytometry. Entry random urine samples were assessed for albumin-to-creatinine ratios (UACR). Urine samples were measured for inflammatory and fibrotic biomarkers using Luminex technology.

RESULTS

Among 96 HIV-infected subjects with measured UACR (87% male, 59% Caucasian, and 89% undetectable HIV RNA with median CD4 of 495.5 cells/μL), 18 patients (19%) had albuminuria. Non-classical (CD14low/+CD16++) monocytes were significantly elevated in subjects with albuminuria (p = 0.034) and were correlated to UACR (r = 0.238, p = 0.019). Elevated non-classical monocyte counts were significant predictors of worsening albuminuria, independent of traditional- and ART-associated risk factors (β = 0.539, p = 0.007). Urine TGF-β1 and collagen-IV were significantly higher in albuminuric compared to non-albuminuric participants (TGF-β1; p = 0.039 and collagen-IV; p = 0.042). Urine TGF-β1 was significantly correlated with non-classical monocyte counts (r = 0.464, p = 0.017).

CONCLUSION

Alterations in monocyte subpopulations and urine pro-fibrotic factors may play a role in kidney dysfunction during chronic HIV infection and warrants further study.

Innate immune reconstitution with suppression of HIV-1

Progressive HIV-1 infection leads to both profound immune suppression and pathologic inflammation in the majority of infected individuals. While adaptive immune dysfunction, as evidenced by CD4⁺ T cell depletion and exhaustion, has been extensively studied, less is known about the functional capacity of innate immune cell populations in the context of HIV-1 infection. Given the broad susceptibility to opportunistic infections and the dysregulated inflammation observed in progressive disease, we hypothesized that there would be significant changes in the innate cellular responses. Using a cohort of patients with multiple samplings before and after antiretroviral therapy (ART) initiation, we demonstrated increased responses to innate immune stimuli following viral suppression, as measured by the production of inflammatory cytokines. Plasma viral load itself had the strongest association with this change in innate functional capacity. We further identified epigenetic modifications in the TNFA promoter locus in monocytes that are associated with viremia, suggesting a molecular mechanism for the observed changes in innate immune function following initiation of ART. These data indicate that suppression of HIV-1 viremia is associated with changes in innate cellular function that may in part determine the restoration of protective immune responses.

Inflammation and Change in Body Weight With Antiretroviral Therapy Initiation in a Multinational Cohort of HIV-Infected Adults

BACKGROUND

Both wasting and obesity are associated with inflammation, but the extent to which body weight changes influence inflammation during human immunodeficiency virus infection is unknown.

METHODS

Among a random virologically suppressed participants of the Prospective Evaluation of Antiretrovirals in Resource-Limited Settings trial, inflammatory markers were measured at weeks 0, 24, and 48 after antiretroviral therapy (ART) initiation. Associations between both baseline and change in body mass index (BMI; calculated as the weight in kilograms divided by the height in meters squared) and changes in inflammation markers were assessed using random effects models.

RESULTS

Of 246 participants, 27% were overweight/obese (BMI, ≥ 25), and 8% were underweight (BMI < 18.5) at baseline. After 48 weeks, 37% were overweight/obese, and 3% were underweight. While level of many inflammatory markers decreased 48 weeks after ART initiation in the overall group, the decrease in C-reactive protein (CRP) level was smaller in overweight/obese participants (P = .01), and the decreases in both CRP (P = .01) and interleukin 18 (P = .02) levels were smaller in underweight participants. Each 1-unit gain in BMI among overweight/obese participants was associated with a 0.02-log10 increase in soluble CD14 level (P = .05), while each 1-unit BMI gain among underweight participants was associated with a 9.32-mg/L decrease in CRP level (P = .001).

CONCLUSIONS

Being either overweight or underweight at ART initiation was associated with heightened systemic inflammation. While weight gain among overweight/obese persons predicted increased inflammation, weight gain among underweight persons predicted reduced inflammation.

Serum oxidized low-density lipoprotein decreases in response to statin therapy and relates independently to reductions in coronary plaque in patients with HIV

OBJECTIVE

Circulating oxidized low-density lipoprotein (oxLDL) levels are elevated in HIV-infected patients and have been associated with atherosclerosis. Statins have been shown to reduce plaque on coronary computed tomography angiography (cCTA) in HIV-infected individuals. Thus, we investigated the effect of statins on serum oxLDL levels and the relationship between changes in oxLDL and coronary atherosclerosis on cCTA in patients with HIV.

DESIGN

We previously conducted a 12-month randomized, placebo-controlled trial with atorvastatin in 40 HIV-infected patients on stable antiretroviral therapy with subclinical coronary atherosclerosis and low-density lipoprotein (LDL)-cholesterol less than 130 mg/dl.

METHODS

In the current analysis, patients underwent cCTA and measurements of serum oxLDL, sCD14, sCD163, lipoprotein phospholipase-A2, and fasting lipids at baseline and end of the study.

RESULTS

Nineteen patients were randomized to atorvastatin and 21 patients to placebo. Serum oxLDL decreased -22.7% (95% CI -28.7 to -16.7) in the atorvastatin group and increased 7.5% (95% CI -3.3 to 18.4) in the placebo group (P < 0.0001). Change in oxLDL significantly correlated with changes in noncalcified plaque volume, total plaque volume, positively remodeled plaque, and low attenuation plaque. The association between changes in oxLDL and noncalcified plaque volume was independent of the baseline 10-year Framingham risk, LDL, CD4 cell count, and viral load.

CONCLUSION

Statins lower oxLDL levels in HIV-infected patients, and reductions in oxLDL are related to improvements in coronary atherosclerosis, independent of traditional cardiovascular risk factors. Reductions in oxLDL may be one mechanism through which statins exert beneficial effects on reducing atherosclerosis in HIV-infected individuals.

Vitamin D, D-dimer, Interferon γ, and sCD14 Levels are Independently Associated with Immune Reconstitution Inflammatory Syndrome: A Prospective, International Study

To determine the immunological profile most important for IRIS prediction, we evaluated 20 baseline plasma biomarkers in Acquired Immunodeficiency Syndrome (AIDS) patients initiating antiretroviral therapy (ART). Patients were enrolled in a randomized, placebo-controlled ART initiation trial in South Africa and Mexico to test whether maraviroc could prevent IRIS. Participants were classified prospectively as having IRIS within 6 months of ART initiation. Twenty plasma biomarkers were measured at study enrollment for 267 participants. Biomarkers were tested for predicting IRIS with adjustment for covariates chosen through forward stepwise selection. Sixty-two participants developed IRIS and of these 19 were tuberculosis (TB)-IRIS. Baseline levels of vitamin D and higher d-dimer, interferon gamma (IFNγ), and sCD14 were independently associated with risk of IRIS in multivariate analyses. TB-IRIS cases exhibited a distinct biosignature from IRIS related to other pathogens, with increased levels of C-reactive protein (CRP), sCD14, IFNγ, and lower levels of Hb that could be captured by a composite risk score. Elevated markers of Type 1 T helper (Th1) response, monocyte activation, coagulation and low vitamin D were independently associated with IRIS risk. Interventions that decrease immune activation and increase vitamin D levels warrant further study.

The Association of Human Cytomegalovirus with Biomarkers of Inflammation and Immune Activation in HIV-1-Infected Women

Three groups of cytomegalovirus (CMV)-seropositive women (total n = 164) were selected from the Chicago Women's Interagency HIV-1 Study to investigate the association between CMV coinfection and immune activation: (1) HIV-1 viremic, (2) HIV-1 aviremic, and (3) HIV-1 uninfected. Quantitative measures of CMV serum IgG, CMV DNA, and serum biomarkers interleukin (IL)-6, soluble CD163 (sCD163), soluble CD14 (sCD14), and interferon gamma-induced protein (IP10) were obtained. Levels of CMV IgG and the serum biomarkers were significantly higher in the HIV-1 viremic group compared to the aviremic and uninfected groups (p < 0.001). No significant associations with CMV IgG levels were found for HIV-uninfected women. When each of the HIV-infected groups was analyzed, sCD14 levels in the viremic women were significantly associated with CMV IgG levels with p < 0.02 when adjusted for age, CD4 count, and HIV viral load. There was also a modest association (p = 0.036) with IL-6 from plasma and cervical vaginal lavage specimens both unadjusted and adjusted for CD4 count and HIV viral load. The association of CMV IgG level with sCD14 implicates the monocyte as a potential site for interaction of the two viruses, which eventually may lead to non-AIDS-defining pathological conditions.

Residual immune activation in combined antiretroviral therapy-treated patients with maximally suppressed viremia

Residual immune activation was studied in 51 HIV-infected individuals, 16 with viral load between 1 and 20 copies/ml and 35 with viral load less than 1 copy/ml, and compared with results in 20 healthy blood donors. Higher T-cell activation and IP-10/CXCL10, MIG/CXCL9 and sCD14 plasma levels persisted in both HIV+ groups. The proportion of activated HLA-DR+ CD4 T cells was inversely correlated with the CD4 nadir and the current CD4 cell counts.

Altered Maturation Status and Possible Immune Exhaustion of CD8 T Lymphocytes in the Peripheral Blood of Patients Presenting With Acute Coronary Syndromes

OBJECTIVE

Inflammation in response to oxidized lipoproteins is thought to play a key role in acute coronary syndromes (ACS), but the pattern of immune activation has not been fully characterized. We sought to perform detailed phenotypic and functional analysis of CD8 T lymphocytes from patients presenting with ACS to determine activation patterns and potential immunologic correlates of ACS.

APPROACH AND RESULTS

We used polychromatic flow cytometry to analyze the cytokine production profiles of naïve, effector, and memory CD8 T cells in patients with ACS compared with control subjects with stable coronary artery disease. ACS was associated with an altered distribution of circulating CD8(+) T-cell maturation subsets with reduced proportions of naïve cells and expansion of effector memory cells. ACS was also accompanied by impaired interleukin-2 production by phenotypically naïve CD8 T cells. These results were validated in a second replication cohort. Naïve CD8 cells from patients with ACS also had increased expression of programmed cell death-1, which correlated with interleukin-2 hypoproduction. In vitro, stimulation of CD8 T cells with oxidized low-density lipoprotein was sufficient to cause programmed cell death-1 upregulation and diminished interleukin-2 production by naïve CD8 T cells.

CONCLUSIONS

In this exploratory analysis, naïve CD8(+) T cells from patients with ACS show phenotypic and functional characteristics of immune exhaustion: impaired interleukin-2 production and programmed cell death-1 upregulation. Exposure to oxidized low-density lipoprotein recapitulates these features in vitro. These data provide evidence that oxidized low-density lipoprotein could play a role in immune exhaustion, and this immunophenotype may be a biomarker for ACS.

Antiretroviral therapy in HIV-1-infected individuals with CD4 count below 100 cells/mm3 results in differential recovery of monocyte activation

Reversal of monocyte and macrophage activation and the relationship to viral suppression and T cell activation are unknown in patients with advanced HIV-1 infection, initiating antiretroviral therapy. This study aimed to determine whether reduction in biomarkers of monocyte and macrophage activation would be reduced in conjunction with viral suppression and resolution of T cell activation. Furthermore, we hypothesized that the addition of CCR5 antagonism (by maraviroc) would mediate greater reduction of monocyte/macrophage activation markers than suppressive antiretroviral therapy alone. In the CCR5 antagonism to decrease the incidence of immune reconstitution inflammatory syndrome study, antiretroviral therapy-naïve patients received maraviroc or placebo in addition to standard antiretroviral therapy. PBMCs and plasma from 65 patients were assessed during 24 wk of antiretroviral therapy for biomarkers of monocyte and macrophage activation. Markers of monocyte and macrophage activation were reduced significantly by 24 wk, including CD14(++)CD16(+) intermediate monocytes (P < 0.0001), surface CD163 (P = 0.0004), CD169 (P < 0.0001), tetherin (P = 0.0153), and soluble CD163 (P < 0.0001). A change in CD38(+), HLA-DR(+) CD8 T cells was associated with changes in CD169 and tetherin expression. Maraviroc did not affect biomarkers of monocyte/macrophage activation but resulted in greater percentages of CCR5-positive monocytes in PBMC. HIV-1 suppression after 24 wk of antiretroviral therapy, with or without maraviroc, demonstrates robust recovery in monocyte subset activation markers, whereas soluble markers of activation demonstrate minimal decrease, qualitatively differentiating markers of monocyte/macrophage activation in advanced disease.

Immune activation in the course of HIV-1 infection: Causes, phenotypes and persistence under therapy

Systemic immune activation is a striking consequence of HIV-1 infection. Even in virologically suppressed patients, some hyperactivity of the immune system and even of the endothelium and of the coagulation pathway may persist. Apart from immune deficiency, this chronic activation may contribute to various morbidities including atherothrombosis, neurocognitive disorders, liver steatosis and osteoporosis, which are currently main challenges. It is therefore of major importance to better understand the causes and the phenotypes of immune activation in the course of HIV-1 infection. In this review we will discuss the various causes of immune activation in HIV-1 infected organisms: the presence of the virus together with other microbes, eventually coming from the gut, CD4+ T cell lymphopenia, senescence and dysregulation of the immune system, and/or genetic factors. We will also describe the activation of the immune system: CD4+ and CD8+ T cells, B cells, NKT and NK cells, dendritic cells, monocytes and macrophages, and neutrophils of the inflammation cascade, as well as of the endothelium and the coagulation system. Finally, we will see that antiretroviral therapy reduces the hyperactivity of the immune and coagulation systems and the endothelial dysfunction, but often does not abolish it. A better knowledge of this phenomenon might help us to identify biomarkers predictive of non AIDS-linked comorbidities, and to define new strategies aiming at preventing their emergence.

Altered Monocyte Phenotype in HIV-1 Infection Tends to Normalize with Integrase-Inhibitor-Based Antiretroviral Therapy

Background

Monocytes are increasingly implicated in the inflammatory consequences of HIV-1 disease, yet their phenotype following antiretroviral therapy (ART) initiation is incompletely defined. Here, we define more completely monocyte phenotype both prior to ART initiation and during 48 weeks of ART.

Methods

Cryopreserved peripheral blood mononuclear cells (PBMCs) were obtained at baseline (prior to ART initiation) and at weeks 12, 24, and 48 of treatment from 29 patients participating in ACTG clinical trial A5248, an open label study of raltegravir/emtricitibine/tenofovir administration. For comparison, cryopreserved PBMCs were obtained from 15 HIV-1 uninfected donors, each of whom had at least two cardiovascular risk factors. Thawed samples were stained for monocyte subset markers (CD14 and CD16), HLA-DR, CCR2, CX3CR1, CD86, CD83, CD40, CD38, CD36, CD13, and CD163 and examined using flow cytometry.

Results

In untreated HIV-1 infection there were perturbations in monocyte subset phenotypes, chiefly a higher frequency and density (mean fluorescence intensity–MFI) of HLA-DR (%-p = 0.004, MFI-p = .0005) and CD86 (%-p = 0.012, MFI-p = 0.005) expression and lower frequency of CCR2 (p = 0.0002) expression on all monocytes, lower CCR2 density on inflammatory monocytes (p = 0.045) when compared to the expression and density of these markers in controls’ monocytes. We also report lower expression of CX3CR1 (p = 0.014) on patrolling monocytes at baseline, compared to levels seen in controls. After ART, these perturbations tended to improve, with decreasing expression and density of HLA-DR and CD86, increasing CCR2 density on inflammatory monocytes, and increasing expression and density of CX3CR1 on patrolling monocytes.

Conclusions

In HIV-1 infected patients, ART appears to attenuate the high levels of activation (HLA-DR, CD86) and to increase expression of the chemokine receptors CCR2 and CX3CR1 on monocyte populations. Circulating monocyte phenotypes are altered in untreated infection and tend to normalize with ART; the role of these cells in the inflammatory environment of HIV-1 infection warrants further study.

Chronic Psoriatic Skin Inflammation Leads to Increased Monocyte Adhesion and Aggregation

Psoriasis patients exhibit an increased risk of death by cardiovascular disease (CVD) and have elevated levels of circulating intermediate (CD14(++)CD16(+)) monocytes. This elevation could represent evidence of monocyte dysfunction in psoriasis patients at risk for CVD, as increases in circulating CD14(++)CD16(+) monocytes are predictive of myocardial infarction and death. An elevation in the CD14(++)CD16(+) cell population has been previously reported in patients with psoriatic disease, which has been confirmed in the cohort of our human psoriasis patients. CD16 expression was induced in CD14(++)CD16(-) classical monocytes following plastic adhesion, which also elicited enhanced β2 but not β1 integrin surface expression, suggesting increased adhesive capacity. Indeed, we found that psoriasis patients have increased monocyte aggregation among circulating PBMCs, which is recapitulated in the KC-Tie2 murine model of psoriasis. Visualization of human monocyte aggregates using imaging cytometry revealed that classical (CD14(++)CD16(-)) monocytes are the predominant cell type participating in these aggregate pairs. Many of these pairs also included CD16(+) monocytes, which could account for apparent elevations of intermediate monocytes. Additionally, intermediate monocytes and monocyte aggregates were the predominant cell type to adhere to TNF-α- and IL-17A-stimulated dermal endothelium. Ingenuity Pathway Analysis demonstrated that monocyte aggregates have a distinct transcriptional profile from singlet monocytes and monocytes following plastic adhesion, suggesting that circulating monocyte responses to aggregation are not fully accounted for by homotypic adhesion, and that further factors influence their functionality.

HIV vasculopathy: role of mononuclear cell-associated Krüppel-like factors 2 and 4

OBJECTIVE

To determine the relationships between Krüppel-like factors (KLF) 2 and 4, immune-activation, and subclinical vascular disease in HIV-infected patients on antiretroviral therapy (ART).

DESIGN

Double-blind, randomized, placebo-controlled trial.

METHODS

We studied 74 HIV-infected adults on ART enrolled in a randomized clinical trial of statin therapy. KLF2 and KLF4 gene expression was measured by quantitative PCR from peripheral blood mononuclear cells (PBMCs) at baseline and after 24 weeks of 10 mg daily rosuvastatin or placebo. At the same time points, T-cell and monocyte activation were assessed by flow cytometry and vascular health was assessed by cardiac computed tomography and carotid ultrasound.

RESULTS

KLF4 expression was negatively correlated with duration of ART (r = -0.351, P = 0.004) and positively correlated with measures of immune activation: proinflammatory monocytes [CD14CD16 (r = 0.343, P = 0.003)], patrolling monocytes [CD14CD16 (r = 0.276, P = 0.017)], and activated CD8 T-lymphocytes [CD8DRCD38 (r = 0.264, P = 0.023)]. KLF2 expression was negatively correlated with subclinical atherosclerosis: mean-mean common carotid artery intima-media thickness (r = -0.231, P = 0.048), mean-max carotid artery intima-media thickness (r = -0.271, P = 0.020), and coronary artery calcium score (r = -0.254, P = 0.029). There were no statistically significant changes in KLF2/4 expression in PBMCs after 24 weeks of rosuvastatin.

CONCLUSION

Expression of KLF4 in PBMCs positively correlates with cellular markers of immune activation, whereas KLF2 expression negatively correlates with markers of subclinical atherosclerosis in this HIV-infected population on ART. Additional studies are needed to determine if targeted interventions might alter KLF2/4 expression to reduce inflammation and vascular risk in humans.

Oxidized LDL Levels Are Increased in HIV Infection and May Drive Monocyte Activation

BACKGROUND

HIV infection is associated with increased cardiovascular risk, and this risk correlates with markers of monocyte activation. We have shown that HIV is associated with a prothrombotic monocyte phenotype, which can be partially mitigated by statin therapy. We therefore explored the relationship between oxidized low-density lipoprotein (oxLDL) particles and monocyte activation.

METHODS

We performed phenotypic analysis of monocytes using flow cytometry on fresh whole blood in 54 patients with HIV and 24 controls without HIV. Plasma levels of oxLDL, soluble CD14, IL-6, and soluble CD163 were measured by enzyme-linked immunosorbent assay. In vitro experiments were performed using flow cytometry.

RESULTS

Plasma levels of oxLDL were significantly increased in HIV infection compared with controls (60.1 units vs. 32.1 units, P < 0.001). Monocyte expression of the oxLDL receptors, CD36 and Toll-like receptor 4, was also increased in HIV. OxLDL levels correlated with markers of monocyte activation, including soluble CD14, tissue factor expression on inflammatory monocytes, and CD36. In vitro stimulation with oxLDL, but not to low-density lipoprotein, resulted in expansion of inflammatory monocytes and increased monocyte expression of tissue factor, recapitulating the monocyte profile we find in HIV disease.

CONCLUSIONS

OxLDL may contribute to monocyte activation, and further study in the context of HIV disease is warranted.

Differential Reduction in Monocyte Activation and Vascular Inflammation With Integrase Inhibitor-Based Initial Antiretroviral Therapy Among HIV-Infected Individuals

BACKGROUND

Little is known about how different antiretrovirals effect inflammation and monocyte activation in human immunodeficiency virus (HIV) infection.

METHODS

We examined plasma specimens obtained during a randomized, double-blinded trial in antiretroviral therapy (ART)-naive HIV-infected adults which compared the efficacy of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/c/FTC/TDF) with that of efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF). From a random sample achieving an HIV type 1 RNA load of <50 copies/mL by week 48, changes over 24 and 48 weeks in levels of biomarkers of monocyte activation (soluble CD14 [sCD14] and soluble CD163 [sCD163]), systemic inflammation (soluble tumor necrosis factor α receptor I [sTNF-RI], interleukin 6 [IL-6], and high-sensitivity C-reactive protein [hsCRP]), and vascular inflammation (lipoprotein-associated phospholipase A2 [Lp-PLA2]) were compared. Multivariable linear regression was used.

RESULTS

A total of 200 participants were included. Significant differences favoring EVG/c/FTC/TDF were noted for changes in sCD14, hsCRP, and Lp-PLA2 levels. Factors independently associated with a larger decrease in the sCD14 level included random assignment to receive EVG/c/FTC/TDF, higher baseline sCD14 level, and larger decreases in hsCRP and sCD163 levels; factors associated with a larger Lp-PLA2 decrease included higher baseline Lp-PLA2 and IL-6 levels, smaller increases in total cholesterol and triglycerides levels, a larger decrease in the sCD14 level, and a smaller decrease in the sCD163 level.

CONCLUSIONS

EVG/c/FTC/TDF led to greater decreases in sCD14, hsCRP, and Lp-PLA2 levels, compared with EFV/FTC/TDF. Randomization group independently predicted the change in sCD14 level, and changes in monocyte activation independently predicted the change in Lp-PLA2 level. There appears to be a more favorable effect of the integrase inhibitor EVG over efavirenz on immune activation, which may affect vascular inflammation.

Monocytes from HIV-infected individuals show impaired cholesterol efflux and increased foam cell formation after transendothelial migration

DESIGN

HIV-infected (HIV+) individuals have an increased risk of atherosclerosis and cardiovascular disease which is independent of antiretroviral therapy and traditional risk factors. Monocytes play a central role in the development of atherosclerosis, and HIV-related chronic inflammation and monocyte activation may contribute to increased atherosclerosis, but the mechanisms are unknown.

METHODS

Using an in-vitro model of atherosclerotic plaque formation, we measured the transendothelial migration of purified monocytes from age-matched HIV+ and uninfected donors and examined their differentiation into foam cells. Cholesterol efflux and the expression of cholesterol metabolism genes were also assessed.

RESULTS

Monocytes from HIV+ individuals showed increased foam cell formation compared with controls (18.9 vs. 0%, respectively, P = 0.004) and serum from virologically suppressed HIV+ individuals potentiated foam cell formation by monocytes from both uninfected and HIV+ donors. Plasma tumour necrosis factor (TNF) levels were increased in HIV+ vs. control donors (5.9 vs. 3.5 pg/ml, P = 0.02) and foam cell formation was inhibited by blocking antibodies to TNF receptors, suggesting a direct effect on monocyte differentiation to foam cells. Monocytes from virologically suppressed HIV+ donors showed impaired cholesterol efflux and decreased expression of key genes regulating cholesterol metabolism, including the cholesterol transporter ABCA1 (P = 0.02).

CONCLUSION

Monocytes from HIV+ individuals show impaired cholesterol efflux and are primed for foam cell formation following transendothelial migration. Factors present in HIV+ serum, including elevated TNF levels, further enhance foam cell formation. The proatherogenic phenotype of monocytes persists in virologically suppressed HIV+ individuals and may contribute mechanistically to increased atherosclerosis in this population.

Highly Active Antiretroviral Therapy (HAART)-Related Hypertriglyceridemia Is Associated With Failure of Recovery of CD14lowCD16+ Monocyte Subsets in AIDS Patients

As cellular reservoirs, CD16 monocyte subsets play important roles in the progression of HIV infection. Previous studies have shown that highly active antiretroviral therapy (HAART) reduced the percentages of CD14CD16 monocyte subsets, but did not recover the percentages of CD14CD16 subsets. Eighty-four chronic HIV-infected, HAART-naïve individuals and 55 HIV-negative subjects (31 without hyperlipidemia and 24 with hypertriglyceridemia) were enrolled. Plasma HIV-1 RNA levels, CD4 T-cell counts, triglycerides, total cholesterol, high-density lipoprotein, and low-density lipoprotein were followed up for 48 weeks during HAART treatment in the longitudinal study. We found that mild hypertriglyceridemia in HIV-negative subjects and HIV-infected patients, naïve to HAART, did not affect the percentage of monocyte subsets. However, a failure of CD14CD16 subset recovery was observed in patients with HAART-related hypertriglyceridemia at 48 weeks. Thus, HAART-related hypertriglyceridemia altered homeostasis of monocyte subsets to antiviral therapy, which might further affect immune reconstitution.

The histone deacetylase inhibitor panobinostat lowers biomarkers of cardiovascular risk and inflammation in HIV patients

OBJECTIVE

To investigate the effect of the histone deacetylase inhibitor panobinostat on HIV-associated inflammation.

DESIGN

Sub-study of a single-arm, phase I/II clinical trial.

METHODS

HIV-infected adults on suppressive antiretroviral therapy received oral panobinostat 20 mg three times per week, every other week, for 8 weeks, that is, four cycles of treatment. Plasma levels of high-sensitivity C-reactive protein, matrix metalloproteinase 9, soluble CD40 ligand and interleukin-6 were determined using human ELISA kits. Soluble endothelia selectin (E-selectin) was measured by a multiplex immunoassay. Total monocyte count, phenotype changes on monocytes and monocyte histone acetylation were analyzed using flow cytometry. Whole-genome expression in peripheral blood mononuclear cells was analyzed at baseline and on-panobinostat employing the Affymetrix Human Transcriptome Array 2.0 microarray assay. Changes from baseline were analyzed using Wilcoxon signed-rank test. For the gene-expression analyses, fold-changes, P values and false detection rate were computed using TAC software.

RESULTS

Panobinostat treatment led to significant reductions in multiple established plasma markers of inflammation. Notably, high-sensitivity C-reactive protein decreased by a median of 58% during treatment and this change persisted for 4 weeks after treatment. Plasma levels of interleukin-6, matrix metalloproteinase 9, E-selectin and soluble CD40 ligand also significantly decreased on and/or postpanobinostat. Additionally, we observed a significant reduction in the proportions of intermediate monocytes and tissue factor-positive monocytes. This suppression of cardiovascular risk biomarkers was associated with a prominent reduction in the expression of genes related to inflammation and atherosclerosis.

CONCLUSION

Collectively, these data indicate that panobinostat may have therapeutic potential to target excess inflammation in HIV patients with high cardiovascular risk.

Brief report: Endothelial colony-forming cells and inflammatory monocytes in HIV

The relationships between HIV infection, monocyte activation, and endothelial colony-forming cells (ECFCs) are unknown. We compared ECFC, intermediate monocytes (CD14 CD16), and nonclassical monocytes (CD14 CD16) levels in HIV-infected participants virologically suppressed on antiretroviral therapy, HIV-infected treatment-naive participants, and HIV-uninfected healthy controls. ECFC levels were significantly higher in the HIV-infected virologically suppressed group compared with the uninfected controls. CD14 CD16 percentages (but not CD14 CD16 cells) were significantly higher in both HIV-infected groups vs. uninfected controls. In the HIV-infected groups, ECFCs and CD14 CD16 intermediate monocytes were significantly and inversely correlated. Lower availability of ECFCs may partly explain the relationship between greater intermediate monocytes and atherosclerosis in HIV.

Plasma levels of cytokines and chemokines and the risk of mortality in HIV-infected individuals: a case-control analysis nested in a large clinical trial

BACKGROUND

All-cause mortality and serious non-AIDS events (SNAEs) in individuals with HIV-1 infection receiving antiretroviral therapy are associated with increased production of interleukin-6 which appears to be driven by monocyte/macrophage activation. Plasma levels of other cytokines or chemokines associated with immune activation might also be biomarkers of an increased risk of mortality and/or SNAEs.

METHODS

Baseline plasma samples from 142 participants enrolled into the Strategies for Management of Antiretroviral Therapy study, who subsequently died, and 284 matched controls, were assayed for levels of 15 cytokines and chemokines. Cytokine and chemokine levels were analysed individually and when grouped according to function (innate/proinflammatory response, cell trafficking and cell activation/proliferation) for their association with the risk of subsequent death.

RESULTS

Higher plasma levels of proinflammatory cytokines (interleukin-6 and tumour necrosis factor-α) were associated with an increased risk of all-cause mortality but in analyses adjusted for potential confounders, only the association with interleukin-6 persisted. Increased plasma levels of the chemokine CXCL8 were also associated with all-cause mortality independently of hepatitis C virus status but not when analyses were adjusted for all confounders. In contrast, higher plasma levels of cytokines mediating cell activation/proliferation were not associated with a higher mortality risk and exhibited a weak protective effect when analysed as a group.

CONCLUSION

Whereas plasma levels of interleukin-6 are the most informative biomarker of cytokine dysregulation associated with all-cause mortality in individuals with HIV-1 infection, assessment of plasma levels of CXCL8 might provide information about causes of mortality and possibly SNAEs.

Changes in Inflammation and Immune Activation With Atazanavir-, Raltegravir-, Darunavir-Based Initial Antiviral Therapy: ACTG 5260s

BACKGROUND

It is unclear whether the integrase inhibitor raltegravir (RAL) reduces inflammation and immune activation compared with ritonavir-boosted protease inhibitors (PIs).

METHODS

In a prospective, randomized, multicenter clinical trial that included 328 human immunodeficiency type 1 (HIV-1)-infected, treatment-naive participants were randomized to receive tenofovir disoproxil fumarate-emtricitabine (TDF/FTC) plus atazanavir/ritonavir (ATV/r), darunavir/ritonavir (DRV/r), or RAL. A total of 234 participants (71%) with HIV-1 RNA levels <50 copies/mL by week 24 were included. Plasma biomarkers of inflammation and coagulation that were analysed included high-sensitivity C-reactive protein, interleukin-6 (IL-6), GlycA, D-dimer, soluble CD14 (sCD14), sCD163, and sIL-2r; blood cellular markers included %CD38+DR+ of T-cell subsets and %CD14+CD16+ and%CD14(dim)CD16+ monocyte subsets. Changes from baseline were examined at earlier (24 or 48 weeks) and later (96 weeks) time points, with 95% confidence intervals on fold-change. Pairwise treatment groups were compared using Wilcoxon rank sum tests, with P values adjusted for false discovery rate control.

RESULTS

Changes in biomarkers varied by regimen during the 96 weeks of follow-up as follows: hsCRP declined with ATV/r and RAL, IL-6 declined only with RAL, and GLycA decreased in all groups. D-dimer declined with ATV/r and DRV/r and was unchanged with RAL. Markers of T-cell activation and sCD163 (but not sCD14 and CD14-+CD16+) declined in all groups.

CONCLUSIONS

Despite some differences in specific markers of inflammation and immune activation between the antiretroviral therapy (ART) regimens, we found no consistent evidence that the reduction of inflammation and immune activation with ART initiation was different between RAL and PI-based regimens.

CLINICAL TRIALS REGISTRATION

NCT00811954 and NCT00851799.

Rosuvastatin reduces vascular inflammation and T-cell and monocyte activation in HIV-infected subjects on antiretroviral therapy

BACKGROUND

Despite suppressive antiretroviral therapy (ART), increased levels of immune activation persist in HIV-infected subjects. Statins have anti-inflammatory effects and may reduce immune activation in HIV disease.

METHODS

Stopping Atherosclerosis and Treating Unhealthy bone with RosuvastatiN in HIV (SATURN-HIV) is a randomized, double-blind placebo-controlled trial assessing the effect of rosuvastatin (10 mg daily) on markers of cardiovascular risk and immune activation in ART-treated patients. T-cell activation was measured by expression of CD38, HLA-DR, and PD1. Monocyte activation was measured with soluble markers (sCD14 and sCD163) and by enumeration of monocyte subpopulations and tissue factor expression. Markers of systemic and vascular inflammation and coagulation were also measured. SATURN-HIV is registered on clinicaltrials.gov (identifier: NCT01218802).

RESULTS

Rosuvastatin, compared with placebo, reduced sCD14 (-10.4% vs 0.5%, P = 0.006), lipoprotein-associated phospholipase A2 (-12.2% vs -1.7%, P = 0.0007), and IP-10 (-27.5 vs -8.2%, P = 0.03) levels after 48 weeks. The proportion of tissue factor-positive patrolling (CD14CD16) monocytes was also reduced by rosuvastatin (-41.6%) compared with placebo (-18.8%, P = 0.005). There was also a greater decrease in the proportions of activated (CD38HLA-DR) T cells between the arms (-38.1% vs -17.8%, P = 0.009 for CD4 cells, and -44.8% vs -27.4%, P = 0.003 for CD8 cells).

CONCLUSIONS

Forty-eight weeks of rosuvastatin treatment reduced significantly several markers of inflammation and lymphocyte and monocyte activation in ART-treated subjects.

Acute Spontaneous Coronary Artery Thrombosis as Initial Presentation of HIV Infection in a Young Man

Introduction. The presentation of acute coronary syndrome (ACS) in young HIV patients may be atypical with different pathophysiological and clinical features. Acute coronary thrombosis, as a presentation of acute coronary syndrome in young patients with HIV, raises diagnostic and treatment challenges. Case Presentation. We describe a case of a 33-year-old African man, without traditional atherosclerotic risk factors, who presented with chest pain of acute onset. Emergent coronary angiography revealed extensive thrombus in the left anterior descending coronary artery with no evidence of atherosclerosis in this or other coronary vessels. Plaque and/or thrombus prolapse through the stent was noted following percutaneous coronary intervention (PCI). Resolution of chest pain and improvement in ST-segment elevation was noted after the procedure. A diagnosis of HIV infection was made during the workup for HIV infection. Conclusion. In young patients without traditional risk factors, HIV infection is a possible etiological factor for spontaneous coronary artery thrombosis. Percutaneous coronary intervention in patients with this presentation may be compounded with atherothrombotic complications. The likely pathophysiological pathway is superficial endothelial cell denudation as a result of chronic inflammation and immune activation.

Inflammation-induced foam cell formation in chronic inflammatory disease

Atherosclerosis is the leading cause of cardiovascular disease and is both a metabolic and inflammatory disease. Two models describe early events initiating atherosclerotic plaque formation, whereby foam cells form in response to hyperlipidaemia or inflammation-associated stimuli. Although these models are inextricably linked and not mutually exclusive, identifying the unique contribution of each in different disease settings remains an important question. Circulating monocytes are key mediators of atherogenesis in both models as precursors to lipid-laden foam cells formed in response to either excess lipid deposition in arteries, signalling via pattern-associated molecular patterns or a combination of the two. In this review, we assess the role of monocytes in each model and discuss how key steps in atherogenesis may be targeted to enhance clinical outcomes in patients with chronic inflammatory disease.

Anaemia is associated with monocyte activation in HIV-infected adults on antiretroviral therapy

BACKGROUND

Anaemia has been linked with mortality in HIV infection. The mechanism of anaemia in the era of contemporary antiretroviral therapy is not understood. The aim of this study was to describe the association between anaemia and markers of immune activation and inflammation in a cohort of HIV-infected adults on stable antiretroviral therapy.

METHODS

We performed a cross-sectional study of HIV-infected adults on antiretroviral therapy with HIV-1 RNA<1,000 copies/ml. Soluble and cellular markers of inflammation and immune activation were measured. Relationships between haemoglobin levels, anaemia (haemoglobin <13 g/dl for men and <12 g/dl for women) and mild anaemia (haemoglobin <14 g/dl for men and <13 g/dl for women) and these markers were explored using multivariable linear regression.

RESULTS

Among the 147 participants, median age was 46 years, 78% were men, 68% were African American and 29% were Caucasian. Median body mass index (BMI) was 26.7 kg/m(2), nadir and current CD4(+) T-cell counts were 179 and 613 cells/mm(3), respectively, and 78% had HIV-1 RNA<50 copies/ml (range 20-600 copies/ml). Median (IQR) haemoglobin was 14.3 (13.1-15.1) g/dl; 14% were anaemic and 33% had at least mild anaemia. In multivariable analyses, mild anaemia was independently associated with female sex, older age, shorter duration of antiretroviral therapy, lower white blood cell count, higher platelet count, higher sCD14 and a greater number of CD14(dim)CD16(+) cells or 'patrolling' monocytes, which remained significant after further adjusting for race and BMI.

CONCLUSIONS

Having haemoglobin <14 g/dl for men and <13 g/dl for women was independently associated with monocyte activation (sCD14 and CD14(dim)CD16(+) cells) in HIV-infected adults on stable antiretroviral therapy.

Characterization of lipid composition and high-density lipoprotein function in HIV-infected individuals on stable antiretroviral regimens

There is an increase in the cardiovascular disease (CVD) morbidity in individuals infected with HIV that may be due to inflammatory lipid modulation not captured by traditional lipid measures. The objective of this study was to perform advanced lipoprotein phenotyping inclusive of the high-density lipoprotein (HDL) cholesterol efflux capacity and lipoprotein particle concentration and size in a well-phenotyped group of 118 patients infected with HIV. We used simple and multivariable analyses to determine the associations between advanced lipoprotein parameters and known cardiometabolic risk factors. Participants were on stable antiretroviral therapy (ART) and had benign traditional lipid panels [median total cholesterol, low-density lipoprotein (LDL)-C, HDL-C, and triglycerides of 178 mg/dl, 108 mg/dl, 44 mg/dl, and 122.5 mg/dl, respectively]. However, advanced lipoprotein phenotyping demonstrated an elevation of LDL particle number (median of 1,233 nmol/liter) and a decrease in LDL size (median of 20.4 nm), along with a decrease in protective, large HDL particles (median of 3.15 μmol/liter) and reduced HDL cholesterol efflux capacity in comparison to controls of other studies. HDL cholesterol efflux capacity was associated with HDL levels (β=0.395, p<0.001), small LDL particle concentration (β=-0.198, p=0.031), insulin sensitivity by the Matsuda index (β=0.218, p=0.029), and the Framingham Risk Score (β=-0.184, p=0.046). We demonstrate an atherogenic lipoprotein profile by NMR spectroscopy and HDL efflux measurement in a group of HIV-infected patients on stable ART with normal lipid panels.

The CD14 C-260T single nucleotide polymorphism (SNP) modulates monocyte/macrophage activation in treated HIV-infected individuals

Background

HIV-infected individuals have an increased risk of cardiovascular disease (CVD). T-allele carriers of the CD14 C-260T single-nucleotide polymorphism (SNP) have reported increased expression of the LPS-binding receptor, CD14 and inflammation in the general population. Our aim was to explore the relationship of this SNP with monocyte/macrophage activation and inflammation and its association with sub-clinical atherosclerosis in HIV-infected individuals.

Methods

Patients with no pre-existing CVD risk factors on suppressive antiretroviral therapy were recruited from University Malaya Medical Centre, Malaysia (n = 84). The CD14 C-260T and TLR4 SNPs, Asp299Gly and Thr399Ile were genotyped and soluble(s) CD14 and sCD163 and high-sensitivity C-reactive protein, hsCRP were measured in plasma. Subclinical atherosclerosis was assessed by measuring carotid intima media thickness (cIMT). The association between CD14 C-260T SNP carriage and cIMT was assessed in a multivariable quantile regression model where a p-value of <0.05 was considered significant.

Results

We found the CD14 C-260T T-allele in 56% of the cohort and evidence of subclinical atherosclerosis in 27%. TT genotype was associated with higher sCD163 (p = 0.009) but only marginally higher sCD14 (p = 0.209) and no difference in hsCRP (p = 0.296) compared to CC/CT. In multivariable analysis, only Framingham risk score was independently associated with higher cIMT while lower sCD163 was trending towards significance. No association was found in TT-genotype carriers and cIMT measurements.

Conclusion

The CD14 C-260T SNP was associated with increased monocyte activation but not systemic inflammation or cIMT in this HIV-infected cohort with low CVD risk profile.

Cardiovascular disease risk in an aging HIV population: not just a question of biology

PURPOSE OF REVIEW

The objective of this review is to appraise recently published literature that describes the relationship between HIV, biologic and environmental risk factors, and cardiovascular disease (CVD) risk with particular emphasis on the aging HIV population and to demonstrate that these biologic and environmental factors may interact to increase the risk of CVD in the HIV population.

RECENT FINDINGS

The mechanisms linking HIV and CVD are multifactorial and encompass biological and 'environmental' modalities including multimorbid conditions that co-occur with HIV, immunologic alterations associated with HIV, polypharmacy (which affects adherence and increases likelihood of adverse drug-drug interactions) and healthcare disparities in CVD risk reduction by HIV status.

SUMMARY

Data regarding optimal treatment strategies that balance immunological restoration and CVD risk reduction are needed.

Elevated plasma soluble CD14 and skewed CD16+ monocyte distribution persist despite normalisation of soluble CD163 and CXCL10 by effective HIV therapy: a changing paradigm for routine HIV laboratory monitoring?

Objective

We investigated plasma and flow cytometric biomarkers of monocyte status that have been associated with prognostic utility in HIV infection and other chronic inflammatory diseases, comparing 81 HIV⁺ individuals with a range of treatment outcomes to a group of 21 healthy control blood donors. Our aim is to develop and optimise monocyte assays that combine biological relevance, clinical utility, and ease of adoption into routine HIV laboratory practice.

Design

Cross-sectional evaluation of concurrent plasma and whole blood samples.

Methods

A flow cytometry protocol was developed comprising single-tube CD45, CD14, CD16, CD64, CD163, CD143 analysis with appropriately matched isotype controls. Plasma levels of soluble CD14 (sCD14), soluble CD163 (sCD163) and CXCL10 were measured by ELISA.

Results

HIV status was associated with significantly increased expression of CD64, CD143 and CD163 on CD16⁺ monocytes, irrespective of the virological response to HIV therapy. Plasma levels of sCD14, sCD163 and CXCL10 were also significantly elevated in association with viremic HIV infection. Plasma sCD163 and CXCL10 levels were restored to healthy control levels by effective antiretroviral therapy while sCD14 levels remained elevated despite virological suppression (p<0.001).

Conclusions

Flow cytometric and plasma biomarkers of monocyte activation indicate an ongoing systemic inflammatory response to HIV infection, characterised by persistent alterations of CD16⁺ monocyte expression profiles and elevated sCD14 levels, that are not corrected by antiretroviral therapy and likely to be prognostically significant. In contrast, sCD163 and CXCL10 levels declined on antiretroviral therapy, suggesting multiple activation pathways revealed by these biomarkers. Incorporation of these assays into routine clinical care is feasible and warrants further consideration, particularly in light of emerging therapeutic strategies that specifically target innate immune activation in HIV infection.

Sex differences in monocyte activation in systemic lupus erythematosus (SLE)

Introduction

TLR7/8 and TLR9 signaling pathways have been extensively studied in systemic lupus erythematosus (SLE) as possible mediators of disease. Monocytes are a major source of pro-inflammatory cytokines and are understudied in SLE. In the current project, we investigated sex differences in monocyte activation and its implications in SLE disease pathogenesis.

Methods

Human blood samples from 27 healthy male controls, 32 healthy female controls, and 25 female patients with SLE matched for age and race were studied. Monocyte activation was tested by flow cytometry and ELISA, including subset proportions, CD14, CD80 and CD86 expression, the percentage of IL-6-producing monocytes, plasma levels of sCD14 and IL-6, and urine levels of creatinine.

Results

Monocytes were significantly more activated in women compared to men and in patients with SLE compared to controls in vivo. We observed increased proportions of non-classic monocytes, decreased proportions of classic monocytes, elevated levels of plasma sCD14 as well as reduced surface expression of CD14 on monocytes comparing women to men and lupus patients to controls. Plasma levels of IL-6 were positively related to sCD14 and serum creatinine.

Conclusion

Monocyte activation and TLR4 responsiveness are altered in women compared to men and in patients with SLE compared to controls. These sex differences may allow persistent systemic inflammation and resultant enhanced SLE susceptibility.

Coagulation and morbidity in treated HIV infection

HIV infected patients are at increased risk for venous and arterial thromboembolic events. Multiple markers related to inflammation (IL-6, TNFrI, C-reative protein) and coagulation (tissue factor expression, FVIII, thrombin, fibrinogen and D-dimer levels) are increased in HIV infection, and several are predictive of thrombotic risk and mortality in HIV disease. The mechanisms behind the risk for abnormal coagulation in HIV infection have not been fully elucidated, but may be related to a chronic immune activation and inflammatory state in both untreated and treated HIV infection. The contribution of traditional risk factors, including smoking and dyslipidemia, overly represented in HIV infected patients, must also be considered when assessing thrombotic risk in this setting. Currently, several interventional studies are aimed at reducing inflammation and cardiovascular risk in HIV disease and may provide insights into the determinants of clotting events in HIV infected patients.

Modulation of monocyte subsets in infectious diseases

Monocytes are effector immune cells but a precise analysis of their role in immune response has been precluded by their heterogeneity. Indeed, human monocytes are composed of at least three different subsets with different phenotypic characteristics and functional properties, the so-called classical, intermediate and non-classical monocytes. A review of the literature shows that these monocyte subsets are differently affected during viral, bacterial, parasitic and fungal infections. The expansion of the CD16⁺ compartment (intermediate and non-classical monocytes) is typically observed in the majority of infectious diseases and the increased proportion of CD16⁺ monocytes is likely related to their activation through their direct interaction with the pathogen or the inflammatory context. In contrast, the number of non-classical and intermediate monocytes is decreased in Q fever endocarditis, suggesting that complex mechanisms govern the equilibrium among monocyte subsets. The measurement of monocyte subsets would be useful in better understanding of the role of monocyte activation in the pathophysiology of infectious diseases.

Elevated soluble CD163 plasma levels are associated with disease severity in patients with hemorrhagic fever with renal syndrome

Background

Hantaan virus is a major zoonotic pathogen that causesing hemorrhagic fever with renal syndrome (HFRS). Although HFRS pathogenesis has not been entirely elucidated, the importance of host-related immune responses in HFRS pathogenesis has been widely recognized. CD163, a monocyte and macrophage-specific scavenger receptor that plays a vital function in the hosts can reduce inflammation, is shed during activation as soluble CD163 (sCD163). The aim of this study was to investigate the pathological significance of sCD163 in patients with HFRS.

Methods

Blood samples were collected from 81 hospitalized patients in Tangdu Hospital from October 2011 to January 2014 and from 15 healthy controls. The sCD163 plasma levels were measured using a sandwich ELISA, and the relationship between sCD163 and disease severity was analyzed. Furthermore, CD163 expression in 3 monocytes subset was analyzed by flow cytometry.

Results

The results demonstrated that sCD163 plasma levels during the HFRS acute phase were significantly higher in patients than during the convalescent stage and the levels in the healthy controls (P<0.0001). The sCD163 plasma levels in the severe/critical group were higher than those in the mild/moderate group during the acute (P<0.0001). A Spearman correlation analysis indicated that the sCD163 levels were positively correlated with white blood cell, serum creatine, blood urea nitrogen levels, while they were negatively correlated with blood platelet levels in the HFRS patients. The monocyte subsets were significantly altered during the acute stage. Though the CD163 expression levels within the monocyte subsets were increased during the acute stage, the highest CD163 expression level was observed in the CD14++CD16+ monocytes when compared with the other monocyte subsets.

Conclusion

sCD163 may be correlated with disease severity and the disease progression in HFRS patients; however, the underlying mechanisms should be explored further.

Glucose transporter 1-expressing proinflammatory monocytes are elevated in combination antiretroviral therapy-treated and untreated HIV+ subjects

Monocyte activation during HIV-1 infection is associated with increased plasma levels of inflammatory markers and increased risk for premature development of age-related diseases. Because activated monocytes primarily use glucose to support cellular metabolism, we hypothesized that chronic monocyte activation during HIV-1 infection induces a hypermetabolic response with increased glucose uptake. To test this hypothesis, we evaluated glucose transporter 1 (Glut1) expression and glucose uptake by monocyte subpopulations in HIV-seropositive (HIV(+)) treatment-naive individuals (n = 17), HIV(+) individuals on combination antiretroviral therapy with viral loads below detection (n = 11), and HIV-seronegative (HIV(-)) individuals (n = 16). Surface expression of Glut1 and cellular uptake of the fluorescent glucose analog 2-(N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino)-2 deoxyglucose were analyzed by flow cytometry on monocyte subpopulations. Irrespective of treatment status, monocytes from HIV(+) persons had significantly increased surface expression of Glut1 compared with those from HIV(-) controls. Nonclassical (CD14(+)CD16(++)) and intermediate (CD14(++)CD16(+)) monocyte subpopulations showed higher Glut1 expression than did classical (CD14(++)CD16(-)) monocytes. Intermediate monocytes from treatment-naive HIV(+) individuals also showed increased uptake of 2-(N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino)-2 deoxyglucose compared with those from HIV(-) controls. Our results show that HIV infection is associated with increased glucose metabolism in monocytes and that Glut1 expression by proinflammatory monocytes is a potential marker of inflammation in HIV-infected subjects. However, the possibility exists whereby other Gluts such as Glut3 and Glut4 may also support the influx of glucose into activated and inflammatory monocyte populations.

Neutrophils in antiretroviral therapy-controlled HIV demonstrate hyperactivation associated with a specific IL-17/IL-22 environment

BACKGROUND

Despite control of HIV infection under antiretroviral therapy (ART), immune T-cell activation persists in patients with controlled HIV infection, who are at higher risk of inflammatory diseases than the general population. PMNs play a key role in host defenses against invading microorganisms but also potentiate inflammatory reactions in cases of excessive or misdirected responses.

OBJECTIVE

The aim of our study was to analyze PMN functions in 60 ART-treated and controlled HIV-infected patients (viral load, <20 RNA copies/mL; CD4 count, ≥ 350 cells/mm(3)) with (HIV[I] group) and without (HIV[NI] group) diseases related to an inflammatory process and to compare them with 22 healthy control subjects.

METHODS

Flow cytometry was used to evaluate PMN functions in whole-blood conditions. We studied in parallel the activation markers of T lymphocytes and monocytes and the proinflammatory cytokine environment.

RESULTS

Blood samples from HIV-infected patients revealed basal PMN hyperactivation associated with deregulation of the apoptosis/necrosis equilibrium. Interestingly, this hyperactivation was greater in HIV(I) than HIV(NI) patients and contrasted with a lack of monocyte activation in both groups. The percentage of circulating cells producing IL-17 was also significantly higher in HIV-infected patients than in control subjects and was positively correlated with markers of basal PMN activation. In addition, the detection of IL-22 overproduction in HIV(NI) patients suggests that it might contribute to counteracting chronic inflammatory processes during HIV infection.

CONCLUSIONS

This study thus demonstrates the presence of highly activated PMNs in HIV-infected patients receiving effective ART and the association of these cells with a specific IL-17/IL-22 environment.

Inflammatory co-morbidities in HIV+ individuals: learning lessons from healthy ageing

Increased life expectancy due to improved efficacy of cART has uncovered an increased risk of age-related morbidities in HIV+ individuals and catalyzed significant research into mechanisms driving these diseases. HIV infection increases the risk of non-communicable diseases common in the aged, including cardiovascular disease, neurocognitive decline, non-AIDS malignancies, osteoporosis, and frailty. These observations suggest that HIV accelerates immunological ageing, and there are many immunological similarities with the aged, including shortened telomeres, accumulation of senescent T cells and altered monocyte phenotype/function. However, the most critical similarity between HIV+ individuals and the elderly, which most likely underpins the heightened risk of non-communicable diseases, is chronic inflammation and associated immune activation. Here, we review the similarities between HIV+ individuals and the aged regarding the pathogenesis of inflammatory diseases, the current evidence for mechanisms driving these processes and discuss current and potential therapeutic strategies for addressing inflammatory co-morbidity in HIV+ infection.

Risk of coronary heart disease in patients with HIV infection

The lives of individuals infected with HIV who have access to combination antiretroviral therapy (cART) are substantially prolonged, which increases the risk of developing non-AIDS comorbidities, including coronary heart disease (CHD). In Europe and the USA, individuals with HIV infection have a ∼1.5-fold increased risk of myocardial infarction relative to uninfected individuals. In Africa, the relative risk of myocardial infarction is unknown, but broadened access to life-extending cART suggests that rates of CHD will rise in this and other resource-constrained regions. Atherogenesis in HIV is affected by complex interactions between traditional and immune risk factors. cART has varied, regimen-specific effects on metabolic risk factors. Overall, cART seems to lessen proatherogenic immune activation, but does not eliminate it even in patients in whom viraemia is suppressed. Current strategies to decrease the risk of CHD in individuals infected with HIV include early initiation of cART regimens with the fewest metabolic adverse effects, and careful management of traditional CHD risk factors throughout treatment. Future strategies to prevent CHD in patients with HIV infection might involve the use of HIV-tailored CHD risk-prediction paradigms and the administration of therapies alongside cART that will further decrease proatherogenic HIV-specific immune activation.

Protease inhibitor monotherapy is associated with a higher level of monocyte activation, bacterial translocation and inflammation

Introduction

Monotherapy with protease-inhibitors (MPI) may be an alternative to cART for HIV treatment. We assessed the impact of this strategy on immune activation, bacterial translocation and inflammation.

Methods

We performed a cross-sectional study comparing patients on successful MPI (n=40) with patients on cART (n=20). Activation, senescence, exhaustion and differentiation stage in CD4+ and CD8+ T lymphocyte subsets, markers of monocyte activation, microbial translocation, inflammation, coagulation and low-level viremia were assessed.

Results

CD4+ or CD8+ T lymphocyte subset parameters were not significantly different between both groups. Conversely, as compared with triple cART, MPI patients showed a higher proportion of activated monocytes (CD14+ CD16−CD163+ cells, p=0.031), soluble markers of monocyte activation (sCD14 p=0.004, sCD163 p=0.002), microbial translocation (lipopolysaccharide (LPS)-binding protein; LBP p=0.07), inflammation (IL-6 p=0.04) and low-level viremia (p=0.035). In a multivariate model, a higher level of CD14+ CD16−CD163+ cells and sCD14, and presence of very low-level viremia were independently associated with MPI. Monocyte activation was independently associated with markers of inflammation (IL-6, p=0.006), microbial translocation (LBP, p=0.01) and low-level viremia (p=0.01).

Conclusions

Patients on MPI showed a higher level of monocyte activation than patients on standard therapy. Microbial translocation and low-level viremia were associated with the high level of monocyte activation observed in patients on MPI. The long-term clinical consequences of these findings should be assessed.

The importance of monocytes and macrophages in HIV pathogenesis, treatment, and cure

Monocytes and macrophages play critical roles in HIV transmission, viral spread early in infection, and as a reservoir of virus throughout infection. There has been a recent resurgence of interest in the biology of monocyte subsets and macrophages and their role in HIV pathogenesis, partly fuelled by efforts to understand difficulties in achieving HIV eradication. This article examines the importance of monocyte subsets and tissue macrophages in HIV pathogenesis. Additionally, we will review the role of monocytes and macrophages in the development of serious non-AIDS events including cardiovascular disease and neurocognitive impairment, their significance in viral persistence, and how these cells represent an important obstacle to achieving HIV eradication.

IFN-stimulated gene LY6E in monocytes regulates the CD14/TLR4 pathway but inadequately restrains the hyperactivation of monocytes during chronic HIV-1 infection

Owing to ongoing recognition of pathogen-associated molecular patterns, immune activation and upregulation of IFN-stimulated genes (ISGs) are sustained in the chronically infected host. Albeit most ISGs are important effectors for containing viral replication, some might exert compensatory immune suppression to limit pathological dysfunctions, although the mechanisms are not fully understood. In this study, we report that the ISG lymphocyte Ag 6 complex, locus E (LY6E) is a negative immune regulator of monocytes. LY6E in monocytes negatively modulated CD14 expression and subsequently dampened the responsiveness to LPS stimulation in vitro. In the setting of chronic HIV infection, the upregulation of LY6E was correlated with reduced CD14 level on monocytes; however, the immunosuppressive effect of LY6E was not adequate to remedy the hyperresponsiveness of activated monocytes. Taken together, the regulatory LY6E pathway in monocytes represents one of negative feedback mechanisms that counterbalance monocyte activation, which might be caused by LPS translocation through the compromised gastrointestinal tract during persistent HIV-1 infection and may serve as a potential target for immune intervention.

The role of T cells in the development of cardiovascular disease in HIV-infected patients

Cardiovascular disease (CVD) is highly prevalent in HIV-infected patients. Besides the classical cardiovascular risk factors, HIV related factors play a role, such as immune activation and treatment with highly active antiretroviral therapy (HAART). The resulting T cell activation is regarded as one of the driving forces behind this accelerated atherogenesis. Interventions, such as early treatment and anti-inflammatory therapy, decreasing T cell activation might lead to a lower incidence of CVD in future HIV infected patients. This review specifically explores the role of T cells in the development of atherosclerosis in HIV-infected patients.

Higher levels of circulating monocyte-platelet aggregates are correlated with viremia and increased sCD163 levels in HIV-1 infection

Increased levels of monocyte-platelet aggregates (MPAs) are reported to be highly correlated with cardiovascular events. In this study, the MPA levels in different monocyte subsets and the associations between MPA levels, HIV-1 viremia and monocyte activation were evaluated during HIV-1 infection. The results showed that the percentages of MPAs in all three monocyte subsets were higher in HIV-1-infected subjects than in healthy controls, and were associated with the plasma viral load in the non-classical and intermediate monocyte subsets. The plasma levels of sCD14 and sCD163 were upregulated in HIV-1 infection and were positively associated with viral loads and negatively associated with CD4 counts. P-selectin glycoprotein ligand-1 (PSGL-1) was shown to be expressed at significantly lower levels on all three monocyte subsets and was negatively correlated with the sCD163 level. The MPA level was correlated with the levels of plasma sCD163 but negatively correlated with CD163 and PSGL-1 on all three monocyte subsets. An elevated immune activation status was correlated with increased MPA formation, underlying the potential interaction between monocyte activation and MPA formation. This interaction may be related to a higher thromboembolic risk in patients infected with HIV-1.Cellular & Molecular Immunology advance online publication, 11 August 2014; doi:10.1038/cmi.2014.66.

Rosuvastatin preserves renal function and lowers cystatin C in HIV-infected subjects on antiretroviral therapy: the SATURN-HIV trial

BACKGROUND

In chronic human immunodeficiency virus (HIV) infection, plasma cystatin C may be influenced by factors other than glomerular filtration rate such as inflammation. Statins may improve cystatin C by improving glomerular function or by decreasing inflammation.

METHODS

The Stopping Atherosclerosis and Treating Unhealthy Bone With Rosuvastatin in HIV (SATURN-HIV) trial randomized 147 patients on stable antiretroviral therapy (ART) with low-density lipoprotein cholesterol ≤130 mg/dL to blinded 10 mg daily rosuvastatin or placebo. We analyzed relationships of baseline and 0- to 24-week changes in plasma cystatin C concentration with measures of vascular disease, inflammation, and immune activation.

RESULTS

Median age was 46 (interquartile range, 40-53) years; 78% were male, 68% African American. Tenofovir and protease inhibitors were used in 88% and 49% of subjects, respectively. Baseline cystatin C was associated with higher carotid intima-media thickness and epicardial adipose tissue independent of age, sex, and race. Biomarkers of endothelial activation and inflammation were associated with cystatin C in a multivariable model independent of creatinine-based estimated glomerular filtration rate (eGFRcr). After 24 weeks, statin use slowed mean eGFRcr decline (1.61 vs -3.08 mL/minute/1.73 m(2) for statin vs placebo; P = .033) and decreased mean cystatin C (-0.034 mg/L vs 0.010 mg/L; P = .008). Within the statin group, changes in cystatin C correlated with changes in endothelial activation, inflammation, and T-cell activation.

CONCLUSIONS

Rosuvastatin 10 mg daily reduces plasma cystatin C and slows kidney function decline in HIV-infected patients on ART. Reductions in cystatin C with statin therapy correlate with reductions in inflammatory biomarkers. Relationships between cystatin C, kidney function, and cardiovascular risk in HIV may be mediated in part by inflammation. Clinical Trials Registration. NCT01218802.