T-cell phenotypes, apoptosis and inflammation in HIV+ patients on virologically effective cART with early atherosclerosis

Inflammation in HIV and Its Impact on Atherosclerotic Cardiovascular Disease

People living with HIV have a 1.5- to 2-fold increased risk of developing cardiovascular disease. Despite treatment with highly effective antiretroviral therapy, people living with HIV have chronic inflammation that makes them susceptible to multiple comorbidities. Several factors, including the HIV reservoir, coinfections, clonal hematopoiesis of indeterminate potential (CHIP), microbial translocation, and antiretroviral therapy, may contribute to the chronic state of inflammation. Within the innate immune system, macrophages harbor latent HIV and are among the prominent immune cells present in atheroma during the progression of atherosclerosis. They secrete inflammatory cytokines such as IL (interleukin)-6 and tumor necrosis-α that stimulate the expression of adhesion molecules on the endothelium. This leads to the recruitment of other immune cells, including cluster of differentiation (CD)8+ and CD4+ T cells, also present in early and late atheroma. As such, cells of the innate and adaptive immune systems contribute to both systemic inflammation and vascular inflammation. On a molecular level, HIV-1 primes the NLRP3 (NLR family pyrin domain containing 3) inflammasome, leading to an increased expression of IL-1β, which is important for cardiovascular outcomes. Moreover, activation of TLRs (toll-like receptors) by HIV, gut microbes, and substance abuse further activates the NLRP3 inflammasome pathway. Finally, HIV proteins such as Nef (negative regulatory factor) can inhibit cholesterol efflux in monocytes and macrophages through direct action on the cholesterol transporter ABCA1 (ATP-binding cassette transporter A1), which promotes the formation of foam cells and the progression of atherosclerotic plaque. Here, we summarize the stages of atherosclerosis in the context of HIV, highlighting the effects of HIV, coinfections, and antiretroviral therapy on cells of the innate and adaptive immune system and describe current and future interventions to reduce residual inflammation and improve cardiovascular outcomes among people living with HIV.

Exercise to Prevent Accelerated Vascular Aging in People Living With HIV

Given advances in antiretroviral therapy, the mortality rate for HIV infection has dropped considerably over recent decades. However, people living with HIV (PLWH) experience longer life spans coupled with persistent immune activation despite viral suppression and potential toxicity from long-term antiretroviral therapy use. Consequently, PLWH face a cardiovascular disease (CVD) risk more than twice that of the general population, making it the leading cause of death among this group. Here, we briefly review the epidemiology of CVD in PLWH highlighting disparities at the intersections of sex and gender, age, race/ethnicity, and the contributions of social determinants of health and psychosocial stress to increased CVD risk among individuals with marginalized identities. We then overview the pathophysiology of HIV and discuss the primary factors implicated as contributors to CVD risk among PLWH on antiretroviral therapy. Subsequently, we highlight the functional evidence of premature vascular dysfunction as an early pathophysiological determinant of CVD risk among PLWH, discuss several mechanisms underlying premature vascular dysfunction in PLWH, and synthesize current research on the pathophysiological mechanisms underlying accelerated vascular aging in PLWH, focusing on immune activation, chronic inflammation, and oxidative stress. We consider understudied aspects such as HIV-related changes to the gut microbiome and psychosocial stress, which may serve as mechanisms through which exercise can abrogate accelerated vascular aging. Emphasizing the significance of exercise, we review various modalities and their impacts on vascular health, proposing a holistic approach to managing CVD risks in PLWH. The discussion extends to critical future study areas related to vascular aging, CVD, and the efficacy of exercise interventions, with a call for more inclusive research that considers the diversity of the PLWH population.

Cytomegalovirus Immunoglobulin G (IgG) Titer and Coronary Artery Disease in People With Human Immunodeficiency Virus (HIV)

BACKGROUND

Cytomegalovirus (CMV) infection is thought to result in increased immune activation in people with human immunodeficiency virus (HIV, PWH). Although some data have linked asymptomatic CMV infection to cardiovascular disease among PWH, it remains unknown whether CMV is associated with increased or high-risk coronary plaque.

METHODS

The Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) enrolled PWH aged 40-75 years on stable antiretroviral therapy (ART) with low-to-moderate atherosclerotic cardiovascular disease (ASCVD) risk. Among a subset of US REPRIEVE participants, coronary plaque was assessed by coronary computed tomography angiography. Here, we assessed the relationship between CMV immunoglobulin G (IgG) titer and (1) levels of immune activation, (2) inflammatory biomarkers, and (3) coronary plaque phenotypes at study entry.

RESULTS

Of 672 participants, mean age was 51 years, 83% were men, median ASCVD risk score was 4.5%, and 66% had current CD4+ T-cell count ≥500 cells/mm3. Higher CMV IgG quartile group was associated with older age and lower current and nadir CD4+ T-cell counts. CMV IgG titer was associated with specific inflammatory biomarkers (sCD163, MCP-1, interleukin [IL]-6, hsCRP) in univariate analysis, but not after controlling for HIV-specific factors. In contrast, CMV IgG titer was not associated with coronary artery disease indexes, including presence of plaque, coronary artery calcium (CAC) score >0, vulnerable plaque presence, or Leaman score >5.

CONCLUSIONS

No meaningful association was seen between CMV IgG titer and coronary artery disease indexes among ART-treated PWH at study enrollment. Longitudinal assessments in REPRIEVE will determine the relationship of CMV IgG titer to plaque progression and cardiovascular events.

CLINICAL TRIALS REGISTRATION

NCT02344290.

Cardiovascular Disease and Thrombosis in HIV Infection

HIV infection has transitioned from an acute, fatal disease to a chronic one managed by antiretroviral therapy. Thus, the aging population of people living with HIV (PLWH) continues to expand. HIV infection results in a dysregulated immune system, wherein CD4+ T cells are depleted, particularly in the gastrointestinal tract, disrupting the gut epithelial barrier. Long-term HIV infection is associated with chronic inflammation through potentially direct mechanisms caused by viral replication or exposure to viral proteins and indirect mechanisms resulting from increased translocation of microbial products from the intestine or exposure to antiretroviral therapy. Chronic inflammation (as marked by IL [interleukin]-6 and CRP [C-reactive protein]) in PLWH promotes endothelial cell dysfunction and atherosclerosis. PLWH show significantly increased rates of cardiovascular disease, such as myocardial infarction (risk ratio, 1.79 [95% CI, 1.54-2.08]) and stroke (risk ratio, 2.56 [95% CI, 1.43-4.61]). In addition, PLWH have increased levels of the coagulation biomarker D-dimer and have a two to ten-fold increased risk of venous thromboembolism compared with the general population. Several small clinical trials analyzed the effect of different antithrombotic agents on platelet activation, coagulation, inflammation, and immune cell activation. Although some markers for coagulation were reduced, most agents failed to reduce inflammatory markers in PLWH. More studies are needed to understand the underlying mechanisms driving inflammation in PLWH to create better therapies for lowering chronic inflammation in PLWH. Such therapies can potentially reduce atherosclerosis, cardiovascular disease, and thrombosis rates in PLWH and thus overall mortality in this population.

Effect of Antiretroviral Therapy on Cardiac Risk Markers in People Living with HIV/AIDS

Introduction:

Chronic HIV infection and antiretroviral therapy (ART) are the major causes of cardiovascular diseases (CVDs) and mortality in HIV patients. This study was conducted to look upon the effect of ART on CVD risk markers in patients on different ART regimens and ART-naïve patients.

Methods:

It was a cross-sectional, observational study done on 120 HIV-infected patients. CV risk markers were assessed and correlated with disease-specific factors within individual subgroups differentiated as Group A (ART naïve), Group B (first-line ART), and Group C (second-line ART). Carotid intimal medial thickness (CIMT) and high-sensitivity C reactive protein (hsCRP) were done to classify cases as having CVD.

Results:

CVD risk parameters were found to be significantly higher in cases on ART, as compared to ART-naïve cases. The mean CIMT among cases in Group C, Group B, and Group A was 0.072 ± 0.01 cm, 0.063 ± 0.01 cm, and 0.055 ± 0.01 cm, respectively (P < 0.01). 95%, 65% and 25% cases in Group C, Group B, and Group A, respectively, had high CIMT (>0.06 cm) and were seen to be directly correlated with disease-related factors, i.e., duration of disease and ART, type of ART, and low CD4 cell counts. hsCRP was significantly increased in 65 out of total 120 cases. The mean hsCRP in Group A, Group B, and Group C was 3.69 ± 3.37, 4.21 ± 3.4, and 5.72 ± 3.54 mg/L, respectively (P < 0.01), which corresponds to the high risk of CVD.

Conclusion:

CVD risk parameters of CIMT and hsCRP are seen to be higher in patients on ART than ART-naive subjects.

Prevalence of Silent Atherosclerosis and Other Comorbidities in an Outpatient Cohort of Adults Living with HIV: Associations with HIV Parameters and Biomarkers

People living with HIV (PLWH) are at risk of noninfectious comorbidities. It is important to individualize those at higher risk. In a single-center cohort of PLWH, we performed a cross-sectional analysis of comorbidities, diagnosed according to standard procedures. The primary endpoint was the prevalence of subclinical carotid/coronary atherosclerosis. Secondary endpoints were its association with selected inflammatory/immune activation biomarkers and with other comorbidities. Associations were examined by using Chi-square or Fisher's exact test for categorical variables and Student or Wilcoxon tests for quantitative variables, and a stepwise multivariate logistical model was performed for further exploration. Among 790 participants [median age: 49.8 years (interquartile range, IQR: 44.5-55.6), 77.1% males, median CD4: 536/mm³ (IQR: 390-754), 83.6% with undetectable viral load], asymptomatic atherosclerosis was found in 26% and was associated in multivariate analysis with older age, longer known duration of infection, higher sCD14, and lower adiponectin levels. Hypertension was found in 33.5% of participants, diabetes in 19.4%, renal impairment in 14.6%, elevated low-density lipoprotein-cholesterol in 13.3%, elevated triglyceride/high-density lipoprotein (HDL)-cholesterol ratio in 6.6%, and osteoporosis in 7.9%. The presence of two or more comorbidities was found in 42.1% of participants and was associated in multivariate analysis with older age and longer exposure to antiretrovirals. Comorbidities were diversely associated with biomarkers: osteoporosis with higher IL-6, renal impairment with higher sCD14, hypertension with higher D-dimer, diabetes and elevated triglyceride/HDL-cholesterol ratio both with lower adiponectin and lower 25-hydroxyvitamin D. Asymptomatic atherosclerosis and multimorbidity were frequent in a cohort of middle-aged, well-controlled, PLWH and were associated with traditional and HIV-specific factors. Associations between morbidities and inflammatory/immune activation biomarkers were diverse.

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.

Uraemia-induced immune senescence and clinical outcomes in chronic kidney disease patients

BACKGROUND

Patients with chronic kidney disease (CKD) are more prone to develop premature age-related diseases. Data on immune senescence are scarce in CKD populations, except in end-stage renal disease and dialysis. We designed a longitudinal prospective study to evaluate immune senescence at different CKD stages and its influence on CKD patient outcomes.

METHODS

Clinical and biological data collections were performed on 222 patients at different CKD stages [1-2 (n = 85), 4 (n = 53) and 5 (n = 84)]. Immune senescence biomarkers were measured by cytometry on T cells (CD28, CD57, CD45RA, CD31, γH2A.X) or by quantitative polymerase chain reaction [relative telomere length (RTL)] on peripheral blood mononuclear cells and analysed according to CKD stages and outcomes.

RESULTS

CKD was associated with an increase in immune senescence and inflammation biomarkers, as follows: low thymic output (197 ± 25 versus 88 ± 13 versus 73 ± 21 CD4+CD45RA+CD31+ T cells/mm3), an increased proportion of terminally differentiated T cells (CD8+CD28-CD57+) (24 ± 18 versus 32 ± 17 versus 35 ± 19%) restricted to cytomegalovirus-positive patients, telomere shortening (1.11 ± 0.36 versus 0.78 ± 0.24 versus 0.97 ± 0.21 telomere:single copy ratio) and an increase in C-reactive protein levels [median 2.9 (range 1.8-4.9) versus 5.1 (27-9.6) versus 6.2 (3.4-10.5) mg/L]. In multivariate analysis, shorter RTL was associated with death {hazard ratio [HR] 4.12 [95% confidence interval (CI) 1.44-11.75]}. Low thymic output was associated with infections [HR 1.79 (95% CI (1.34-9.58)] and terminally differentiated CD8+ T-cell expansion with a risk of cardiovascular events [CEs; HR 4.86 (95% CI 1.72-13.72)].

CONCLUSION

CKD was associated with premature immune ageing. Each of these alterations increased the risk of specific age-related diseases, such as RTL and death, thymic function and infections and terminally differentiated CD8+ T-cell expansion and CEs.

Impact of Age and HIV Status on Immune Activation, Senescence and Apoptosis

Introduction

Residual immune dysfunctions, resembling those that occur during normal aging, may persist even in well-treated people with HIV (PWH), and accelerated aging has been proposed. We aimed to determine if HIV infection is an independent risk factor for T-cell immune dysfunctions including increased immune activation, senescence and apoptosis. Moreover, in PWH we aimed to identify the associations between age and immune activation, senescence and apoptosis.

Materials and Methods

We included 780 PWH with suppressed viral replication (<50 copies/mL) and absence of hepatitis B and hepatitis C co-infection and 65 uninfected controls from the Copenhagen Co-morbidity in HIV Infection (COCOMO) Study. Flow cytometry was used to determine T-cell activation (CD38+HLA-DR+), senescence (CD28-CD57+), and apoptosis (CD28-CD95+). T-cell subsets are reported as proportions of CD4+ and CD8+ T-cells. We defined an elevated proportion of a given T-cell subset as above the 75th percentile. Regression models were used to determine the association between HIV status and T-cell subset and in PWH to determine the association between age or HIV-specific risk factors and T-cell subsets. Furthermore, an interaction between HIV status and age on T-cell subsets was investigated with an interaction term in models including both PWH and controls. Models were adjusted for age, sex, BMI, and smoking status.

Results

In adjusted models a positive HIV status was associated with elevated proportions of CD8+ activated (p = 0.009), CD4+ senescent (p = 0.004), CD4+ apoptotic (p = 0.002), and CD8+ apoptotic (p = 0.003) T-cells. In PWH a 10-year increase in age was associated with higher proportions of CD4+ and CD8+ senescent (p = 0.001 and p < 0.001) and CD4+ and CD8+ apoptotic T-cells (p < 0.001 and p < 0.001). However, no interaction between HIV status and age was found. Furthermore, in PWH a CD4+/CD8+ ratio < 1 was associated with elevated proportions of T-cell activation, senescence, and apoptosis.

Discussion

We found evidence of residual T-cell immune dysfunction in well-treated PWH without HBV or HCV co-infection, and age was associated with T-cell senescence and apoptosis. Our data supports that HIV infection has similar effects as aging on T-cell subsets. However, since no interaction between HIV status and age was found on these parameters, we found no evidence to support accelerated immunological aging in PWH.

Monocyte activation and gut barrier dysfunction in South African youth on antiretroviral therapy and their associations with endothelial dysfunction

BACKGROUND

There is evidence for endothelial dysfunction in youth living with perinatally acquired HIV (YLPHIV). However, little data exist on its mechanisms.

METHODS

YLPHIV and age-matched HIV-uninfected (HIV-) youth enrolled in the Cape Town Adolescent Antiretroviral Cohort in South Africa between 9 and 14 years of age were included. YLPHIV were on antiretroviral therapy more than 6 months with viral load less than 400 copies/ml at baseline and 24 months. Serum biomarkers of systemic inflammation, monocyte activation, intestinal integrity, and oxidized LDL-cholesterol were measured at baseline and after 24 months. Endothelial function was measured at 24 months using reactive hyperemic index (RHI); endothelial dysfunction was defined as RHI less than 1.35. Spearman correlation coefficient and quantile regression were used to examine associations between RHI and different biomarkers.

RESULTS

We included 266 YLPHIV and 69 HIV- participants. At baseline, median (Q1, Q3) age was 12 (11, 13) years and 53% were females. YLPHIV had poorer endothelial function compared with HIV- youth (RHI = 1.36 vs. 1.52, P < 0.01). At baseline and 24 months, YLPHIV had higher markers of monocyte activation (soluble CD14), gut barrier dysfunction (intestinal fatty acid binding protein) and oxidized LDL-cholesterol (P ≤ 0.04) compared with HIV- youth. Among YLPHIV, soluble CD14 remained associated with endothelial dysfunction after adjusting for age, sex, Tanner stage, and antiretroviral therapy duration (β: -0.05, P = 0.01).

CONCLUSION

Despite viral suppression, South African YLPHIV have poor endothelial function and persistent evidence of monocyte activation and gut barrier dysfunction compared with HIV- youth. The long-term clinical significance of gut integrity and monocyte activation needs to be further assessed in YLPHIV.

A rare case of CMV pneumonia in HIV-infection

Cytomegalovirus (CMV) pneumonia is a rare opportunistic infection in the setting of HIV (Human Immunodeficiency Virus)-infection. Establishing accurate diagnosis of CMV pneumonia in HIV-infection can be challenging. Co-infections by multiple opportunistic pathogens are common and a high degree of clinical vigilance to evaluate for multiple infections, including CMV pneumonia, should be maintained. As there can be a degree of overlap in clinical and radiological features amongst different opportunistic infections affecting the lungs, definitive microbiological and cytohistologic evidences are needed. Reliance on microbiological evidence of CMV in respiratory specimens alone for the diagnosis of CMV pneumonia will lead to an over-diagnosis of the condition and unnecessary treatment.

In our case report, we describe a 53-year-old man with recently diagnosed HIV-infection who presented with non-resolving pneumonia. A diagnosis of CMV pneumonia was reached through consistent clinical, radiological, microbiological and cytologic investigations. The patient made a full clinical recovery after being started on anti-CMV treatment.

The effect of HIV infection, antiretroviral therapy on carotid intima-media thickness: A systematic review and meta-analysis

AIMS

We performed a systematic review and meta-analysis on the effect of HIV infection and antiretroviral therapy (ART) on carotid intima-media thickness (cIMT) to elucidate the role of HIV infection and ART. Also, an analysis on the role of ethnicity and gender on cIMT in HIV-infected populations was performed.

MAIN METHODS

We searched the PubMed, Web of Science, the WHO websites and International AIDS Society for published observational studies were conducted by two independent reviewers for studies comparing HIV-infected antiretroviral-experienced patients and/or inexperienced with healthy controls on cIMT. The primary outcome was the standardized mean difference (SMD) of cIMT.

FINDINGS

Twenty studies (five cohort, 15 cross-sectional, and two both cohort and cross-sectional studies) were identified comprising 7948 subjects (4656 HIV-infected; 3292 controls). In cohort studies, the standardized mean 1-year change in cIMT between HIV-infected patients and uninfected controls was not significantly different (0.16 mm/yr; 95% CI, -0.16, 0.49; p = 0.326). In 17 cross-sectional studies, the SMD in cIMT was significantly higher in HIV-infected than uninfected persons (0.27 mm; 95% CI, 0.04, 0.49; p = 0.027). HIV-infected patients on ART exhibited significantly higher SMD in cIMT compared to those not on ART (0.75 mm; 95% CI, 0.30, 1.19; p = 0.001). No confounding effect of gender and ethnicity could be established using meta-regression p > 0.05.

SIGNIFICANCE

HIV infection itself and ART appear to influence the progression of cIMT and hence may be risk factors for cardiovascular events. No firm conclusions could be drawn on the effect of ethnic/race and gender differences on cIMT in HIV-infected populations.

Rationale and design of the Mechanistic Substudy of the Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE): Effects of pitavastatin on coronary artery disease and inflammatory biomarkers

BACKGROUND

People with HIV (PWH) have increased cardiovascular events, inflammation, and high-risk coronary atherosclerosis. Statin therapy has been shown to lower the risk of cardiovascular disease (CVD) in the general population, but whether this results from reductions in coronary atherosclerosis and is mediated by decreased inflammation remains unknown.

METHODS

REPRIEVE is a randomized, placebo-controlled trial of pitavastatin calcium (4 mg/day) vs. placebo enrolling at least 7500 PWH between 40-75 years, on antiretroviral therapy (ART), with low to moderate traditional CVD risk. The Mechanistic Substudy of REPRIEVE (A5333s) is co-enrolling 800 participants from 31 US sites. These participants undergo serial contrast enhanced coronary computed tomography angiography (CCTA) and measurements of biomarkers of inflammation and immune activation at baseline and after 2 years of follow-up. The primary objectives are to determine the effects of pitavastatin on noncalcified coronary atherosclerotic plaque (NCP) volume, low attenuation plaque, and positive remodeling and on changes in immune activation and inflammation and to assess relationships between the two. Changes in CAD will be assessed in a standardized fashion by a core lab with expert readers blinded to time points and participant information; immune activation and inflammation assessment is also performed centrally.

RESULTS

To date the Mechanistic Substudy has completed planned enrollment, with 805 participants.

CONCLUSION

This study represents the first large, randomized, CCTA-based assessment of the effects of a primary prevention strategy for CVD on high-risk CAD, immune activation and inflammation among PWH. The study will assess pitavastatin's effects on coronary plaque, and the interrelationship of these changes with biomarkers of immune activation and inflammation in PWH to determine mechanisms of CVD prevention and improved outcomes in this population.

Diabetes and dyslipidaemia are associated with oxidative stress independently of inflammation in long-term antiretroviral-treated HIV-infected patients

AIM

Ageing HIV-infected patients controlled by antiretroviral therapy (ART) frequently present age-related comorbidities, such as cardiovascular (CV) events, diabetes, dyslipidaemia, hypertension and chronic kidney disease (CKD). The prevalence of these comorbidities was evaluated in a cohort of long-term-monitored ART-controlled HIV-infected patients, then followed by a search into whether oxidative stress, like inflammation, might be associated with metabolic parameters and/or comorbidities.

METHODS

Included were 352 long-term ART patients who started with protease inhibitors (PIs) in 1997-1999. They were evaluated at their final visit, 11 years later, for previous CV events, prevalence of diabetes, LDL-related and atherogenic (high TG/HDL) dyslipidaemias, hypertension and CKD. Also measured were circulating biomarkers to explore oxidative stress (Lp-PLA2, oxLDL, oxLDL/LDL ratio, paraoxonase and arylesterase activities), inflammation/immune activation (hsCRP, hsIL-6, D dimer, soluble CD14, β2 microglobulin, cystatin C), adipokines and insulin resistance. Levels were compared in patients with and without each comorbidity or condition using non-parametric correlation tests and multivariate adjusted analyses.

RESULTS

At the final visit, 81.5% of patients were male and were aged (median, IQR) 49 years (45-56); BMI was 23.0 kg/m² (21.1-25.4), CD4+ lymphocytes were 620 cells/mm³ (453-790) and 91.5% had undetectable HIV-1 viral loads. The prevalence of diabetes was 11%, and LDL-related dyslipidaemia 28%, atherogenic dyslipidaemia 9%, hypertension 28%, CKD 9% and previous CV events 9%. Diabetes and atherogenic dyslipidaemia were associated with increased oxidative stress and independently with inflammation. LDL-related dyslipidaemia and impaired fasting glucose were associated with increased oxidative stress. No association of these biomarkers was detected with hypertension, CKD and previous CV events.

CONCLUSION

In long-term-treated HIV-infected patients with frequent comorbid conditions, oxidative stress could be contributing to diabetes and LDL-related and atherogenic dyslipidaemias independently of inflammation.

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.

Asymptomatic HIV People Present Different Profiles of sCD14, sRAGE, DNA Damage, and Vitamins, according to the Use of cART and CD4+ T Cell Restoration

We aimed to analyze markers of immune activation, inflammation, and oxidative stress in 92 asymptomatic HIV-infected patients according to the adequate (AR, >500 cells/mm³) or inadequate (IR, <500 cells/mm³) CD4⁺ T recovery and the presence or absence of antiretroviral treatment (cART). In relation to those newly diagnosed, they were divided into two groups, cART-naïve IR (nIR) and cART-naïve AR (nAR). Among those diagnosed more than five years ago, the following division was made: the cART-naïve long-term nonprogressors (LTNP); patient under cART and AR (tAR); and patients under cART and IR (tIR). We investigated the expression of soluble receptor for advanced glycation end products (sRAGE), high-mobility group-box protein −1 (HMGB1), soluble CD14 (sCD14), IL-8, IL-10, 8-isoprostane, vitamins, and DNA damage. We observed higher levels of sRAGE in tAR as compared to nIR, nAR, LTNP, and more sCD14 than in nIR and nAR. As for IL-10 levels, we found nIR > nAR > LTNP > tAR > tIR. Higher levels of 8-isoprostane were observed in nIR. LTNP presented a higher retinol dosage than tAR and less genotoxic damage induced by oxidative stress than the other groups. We suggest that the therapy, despite being related to lesser immune activation and inflammation, alters the vitamin profile and consequently increases the oxidative stress of patients. In addition, the lowest genotoxic index for LTNP indicates that both VL and cART could be responsible for the increased DNA damage. More studies are needed to understand the influence of cART on persistent immune activation and inflammation.

Low Levels of Endothelial Progenitor Cells and Their Association with Systemic Inflammation and Monocyte Activation in Older HIV-Infected Men

Endothelial progenitor cells (EPCs) repair damaged vascular endothelium, and low circulating EPC levels have been associated with cardiovascular disease (CVD). CD34⁺/KDR⁺ EPCs are commonly reported in the literature and CD34⁺/CD133⁺/KDR⁺ EPCs are rare in circulation but highly specific for endothelial lineage. HIV-infected (HIV+) adults have chronic inflammation and increased CVD risk, but the relationship between CVD, vascular inflammation, and EPCs in HIV remains unclear. In a pilot study, EPCs were measured in 57 HIV+ men [≥50 years old, HIV-1 RNA <50 copies/ml on antiretroviral therapy (ART)] by real-time flow cytometry using cellular immaturity (CD34 and/or CD133) and endothelial commitment (KDR) markers. Fasting inflammatory biomarker levels were measured by ELISA. Median age was 57 years; CD4⁺ T lymphocyte count was 570 cells/mm³. Prevalent CVD risk factors included 16% diabetes, 28% hypertension, 53% dyslipidemia, and 33% smoking. Median (interquartile range) EPC values were CD34⁺/KDR⁺ 0.1 (0.0-0.9) cells/10⁵ peripheral blood mononuclear cells (PBMCs) and CD34⁺/CD133⁺/KDR⁺ 0.1 (0.0-0.9) cells/10⁵ PBMCs. We observed a high prevalence of undetectable CD34⁺/KDR⁺ (40%) and CD34⁺/CD133⁺/KDR⁺ EPCs (44%). Men with undetectable EPCs were more likely to have ≥2 CVD risk factors, lower interleukin-6 (IL-6), and higher sCD163 levels. In these older HIV+ men on suppressive ART, CD34⁺/KDR⁺ and CD34⁺/CD133⁺/KDR⁺ EPC levels were low and often undetectable. Undetectable EPC levels were associated with greater CVD risk factor burden, lower IL-6 (consistent with decreased EPC production stimulus), and higher sCD163 (consistent with monocyte activation and prior CVD associations) levels, suggesting a potential relationship between EPCs and atherosclerotic burden in this population.

Emerging Role and Characterization of Immunometabolism: Relevance to HIV Pathogenesis, Serious Non-AIDS Events, and a Cure

Immune cells cycle between a resting and an activated state. Their metabolism is tightly linked to their activation status and, consequently, functions. Ag recognition induces T lymphocyte activation and proliferation and acquisition of effector functions that require and depend on cellular metabolic reprogramming. Likewise, recognition of pathogen-associated molecular patterns by monocytes and macrophages induces changes in cellular metabolism. As obligate intracellular parasites, viruses manipulate the metabolism of infected cells to meet their structural and functional requirements. For example, HIV-induced changes in immune cell metabolism and redox state are associated with CD4(+) T cell depletion, immune activation, and inflammation. In this review, we highlight how HIV modifies immunometabolism with potential implications for cure research and pathogenesis of comorbidities observed in HIV-infected patients, including those with virologic suppression. In addition, we highlight recently described key methods that can be applied to study the metabolic dysregulation of immune cells in disease states.

Association of Macrophage Inflammation Biomarkers With Progression of Subclinical Carotid Artery Atherosclerosis in HIV-Infected Women and Men

Background

Monocytes and monocyte-derived macrophages promote atherosclerosis through increased inflammation and vascular remodeling. This may be especially true in chronic human immunodeficiency virus (HIV) infection.

Methods

We examined 778 women (74% HIV+) in the Women's Interagency HIV Study and 503 men (65% HIV+) in the Multicenter AIDS Cohort Study who underwent repeated B-mode carotid artery ultrasound imaging in 2004-2013. We assessed baseline associations of the serum macrophage inflammation markers soluble (s)CD163, sCD14, galectin-3 (Gal-3), and Gal-3 binding protein (Gal-3BP) with carotid plaque formation (focal intima-media thickness >1.5 mm) over 7 years.

Results

Marker levels were higher in HIV+ persons versus HIV- persons. Presence of focal plaque increased over time: from 8% to 15% in women, and 24% to 34% in men. After adjustment for demographic, behavioral, and cardiometabolic factors, and CRP and interleukin-6, each standard deviation increase in sCD14 was associated with increased plaque formation (risk ratio [RR] 1.24, 95% confidence interval [CI] 1.07-1.43). This pattern was consistentby sex. sCD163 was associated with plaque formation in virally suppressed HIV+ men (RR 1.52, 95% CI 1.04-2.22); Gal-3BP and Gal-3 were not associated with increased plaque.

Conclusions

sCD14 and sCD163 may play important roles in atherogenesis among HIV+ persons.

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.

Subclinical atherosclerosis in low Framingham risk HIV patients

BACKGROUND

Pathogenesis of atherosclerosis is complex, and differences between HIV-infected patients and general population cannot be completely explained by the higher prevalence of traditional cardiovascular risk factors. We aimed to analyse the association between inflammation and subclinical atherosclerosis in HIV patients with low Framingham risk score.

MATERIALS AND METHODS

Case-control study.

SETTING

Outpatient Infectious Diseases clinic in a university hospital.

SUBJECTS

HIV-1-infected patients aged > 35 years receiving antiretroviral treatment with viral load < 50 copies/mL and Framingham risk score < 10%.

EXCLUSION CRITERIA

inflammatory diseases; dyslipidaemia requiring statins; smoking > 5 cigarettes/day; diabetes; hypertension; vascular diseases.

MAIN OUTCOME

subclinical atherosclerosis determined by ultrasonography: common carotid intima-media thickness greater than 0·8 mm or carotid plaque presence. Explanatory variables: ribosomal bacterial DNA (rDNA), sCD14, interleukin-6 (IL-6) and TNF-α.

RESULTS

Eighty-four patients were included, 75% male, mean age 42 years and mean CD4+ cells 657 ± 215/mm³ . Median Framingham risk score was 1% at 10 years (percentile 25-75: 0·5-4%). Eighteen patients (21%) had subclinical atherosclerosis; the associated factors were older age (P = 0·001), waist-hip ratio (P = 0·01), time from HIV diagnosis (P = 0·02), rDNA (P = 0·04) and IL-6 (P = 0·01). In multivariate analysis, OR for subclinical atherosclerosis was 7 (95% CI, 1.3-40, P = 0.02) and 9 (95% CI, 1.0-85, P = 0.04) for patients older than 44 years and IL-6 > 6·6 pg/mL, respectively.

CONCLUSIONS

Well-controlled HIV patients with low Framingham risk score have a high prevalence of subclinical carotid atherosclerosis, and the main risk factors are age and inflammation. These patients are not receiving primary prophylaxis for cardiovascular events according to current guidelines.

Antithymocyte globulins in renal transplantation-from lymphocyte depletion to lymphocyte activation: The doubled-edged sword

Compelling data suggest that lymphocyte depletion following T cell depleting therapy may induce prolonged CD4 T cell lymphopenia and trigger lymphocyte activation in some patients. These profound and non-reversible immune changes in T cell pool subsets are the consequence of both impaired thymic renewal and peripheral homeostatic proliferation. Chronic viral challenges by CMV play a major role in these immune alterations. Even when the consequences of CD4 T cell lymphopenia have been now well described, recent studies shed new light on the clinical consequences of immune activation. In this review, we will first focus on the mechanisms involved in T cell pool reconstitution after T cell depletion and further consider the clinical consequences of ATG-induced T cell activation and senescence in renal transplant recipients.

CCR5+ CD8 T-cell levels and monocyte activation precede the onset of acute coronary syndrome in HIV-infected patients on antiretroviral therapy

Acute coronary syndrome (ACS) is nowadays one of the leading causes of morbid-mortality in HIV-infected population, but innate and adaptive immune mechanisms preceding this event are unknown. In this work we comprehensively and longitudinally observed, by multiparametric flow cytometry and following a case-control design, increased CCR5⁺CD8⁺ T-cells levels and monocytes expressing activation and adhesion markers in HIV-infected patients who are going to suffer ACS. In addition, we found direct associations between activated CD8⁺ T-cells and myeloid cells that were only statistically significant in the group of patients with ACS and in the follow up time point just before the ACS. Our data highlight the important role of CCR5 in the onset of ACS and suggest this receptor as a marker of cardiovascular risk and potential therapeutic target to prevent the development of such non-AIDS-related event in HIV-infected patients.

Role of T-Cell Dysfunction, Inflammation, and Coagulation in Microvascular Disease in HIV

BACKGROUND

Compared to uninfected adults, HIV-infected adults on antiretroviral therapy are at increased risk of cardiovascular disease. Given the increase in T-cell dysfunction, inflammation, and coagulation in HIV infection, microvascular dysfunction is thought to contribute to this excess cardiovascular risk. However, the relationships between these variables remain undefined.

METHODS AND RESULTS

This was a cross-sectional study of 358 HIV-infected adults from the SCOPE cohort. Macrovascular endothelial function was assessed using flow-mediated dilation of the brachial artery and microvascular function by reactive hyperemia. T-cell phenotype was determined by flow cytometry. Plasma markers of inflammation (tumor necrosis factor-α, interleukin-6, high-sensitivity C-reactive protein, sCD14) and coagulation (fibrinogen, D-dimer) were also measured. In all HIV+ subjects, markers of inflammation (tumor necrosis factor-α, high-sensitivity C-reactive protein), coagulation (D-dimer) and T-cell activation (CD8+PD1+, CD4+interferon+cytomegalovirus-specific) were associated with worse reactive hyperemia after adjusting for traditional cardiovascular risk factors and co-infections. In treated and suppressed subjects, tumor necrosis factor-α and CD8+PD1+ cells remained associated with worse reactive hyperemia after adjustment. Compared to the untreated subjects, CD8+PD1+ cells were increased in the virally suppressed group. Reactive hyperemia was predictive of flow-mediated dilation.

CONCLUSIONS

CD8+PD1+ cells and tumor necrosis factor-α were associated with microvascular dysfunction in all HIV+ subjects and the treated and suppressed group. Additionally, D-dimer, high-sensitivity C-reactive protein, sCD-14, and interleukin-6 were associated with microvascular dysfunction in all HIV+ subjects. Although T-cell dysfunction, inflammation, and microvascular dysfunction are thought to play a role in cardiovascular disease in HIV, this study is the first to look at which T-cell and inflammatory markers are associated with microvascular dysfunction in HIV-infected individuals.

Subclinical myocyte injury, fibrosis and strain in relationship to coronary plaque in asymptomatic HIV-infected individuals

BACKGROUND

Cardiovascular disease (CVD) rates are increased in HIV. The degree to which myocyte injury, strain, and fibrosis occur prior to clinical disease and relate to coronary plaque in HIV is unknown.

OBJECTIVE

To investigate newer cardiac biomarkers of subclinical myocyte injury [high-sensitivity troponin T (hs-cTnT)], strain (amino terminal proB-type natriutretic peptide), fibrosis (soluble ST2, Galectin-3), and vascular inflammation (oxidized LDL, lipoprotein-associated phospholipase A2) in HIV-infected individuals and non-HIV controls and relate these to coronary plaque by cardiac computed tomography angiography.

DESIGN

Observational.

METHODS

Markers were investigated in 155 HIV-infected and 70 non-HIV-infected participants without known CVD and with low traditional CVD risk and related to cardiac computed tomography angiography data.

RESULTS

Age, sex, and race did not differ between the groups. Hs-cTnT [3.1 (3.0, 6.4) vs. 3.0 (3.0, 4.0) ng/l, P = 0.03], Galectin-3 [13.5 (10.6, 18.1) vs. 11.6 (9.9, 14.5) ng/ml, P = 0.002], and soluble ST2 [31.5 (24.5, 41.5) vs. 28.3 (20.2, 33.5) ng/ml, P = 0.01] were significantly higher in HIV-infected participants vs.

CONTROLS

Detectable hs-cTnT (seen in 50% of HIV participants) related to the overall presence of plaque [odds ratio (OR) 2.3, P = 0.01] and particularly to coronary calcium (OR for Agatston calcium score > 0, 3.3, P = 0.0008 and OR for calcified plaque 7.4, P = 0.01) in HIV, but not in non-HIV.

CONCLUSION

Subclinical myocyte injury is observed among young, asymptomatic HIV-infected individuals with low traditional cardiac risk factors. In the setting of HIV infection, the presence of detectable cardiac troponin is strongly associated with coronary plaque, particularly calcified plaque among an asymptomatic group. Future studies are needed to assess if early subclinical injury marked by hs-cTnT predicts plaque progression and cardiac events in HIV.

Greater carotid intima media thickness at a younger age in HIV-infected patients compared with reference values for an uninfected cohort

OBJECTIVES

In contrast to the general population, no decline in cardiovascular disease (CVD) has been noted in HIV-infected patients over the last 10 years. We compared the carotid artery intima media thickness (CIMT) of HIV-infected patients to that of age- and gender-matched reference values and determined the relationship between CVD risk factors and CIMT.

METHODS

A total of 292 HIV-infected patients were enrolled in the study. Data collected included vascular screening data, data obtained using a questionnaire, data obtained from laboratory assessments and CIMT measurement. Using linear regression (adjusted for age/gender/known HIV), the association between HIV-specific and classical cardiovascular risk factors and CIMT was evaluated.

RESULTS

The cohort comprised for 91% of male patients, aged 49.4 ± 10.5 years, with a known duration of HIV infection of 8.8 ± 6.7 years. The mean with standard deviation (mean ± SD) CIMT was 0.77 ± 0.19 mm, compared with 0.58 ± 0.05 mm in the controls. A steeper increase of CIMT per age was seen in the HIV-infected patients. A significant relationship between CIMT and hypertension, diabetes mellitus, smoking, systolic blood pressure, HbA1c (glycated hemoglobin) and ankle brachial index was found. Of the HIV-specific variables, only a relationship between CIMT and length of cART use and between CIMT and (inversely) current cART use was seen.

CONCLUSIONS

A greater CIMT was found in HIV-infected patients compared with controls. In contrast to HIV-specific variables, classical CVD risk factors were associated with a greater CIMT and should therefore be the focus of preventive measures.

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.

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.

CD4+/CD8+ ratio, age, and risk of serious noncommunicable diseases in HIV-infected adults on antiretroviral therapy

OBJECTIVE

In virologically suppressed HIV-infected adults, noncommunicable diseases (NCDs) have been associated with immune senescence and low CD4/CD8 lymphocyte ratio. Age differences in the relationship between CD4/CD8 ratio and NCDs have not been described.

DESIGN

Observational cohort study.

METHODS

We assessed CD4/CD8 ratio and incident NCDs (cardiovascular, cancer, liver, and renal diseases) in HIV-infected adults started on antiretroviral therapy between 1998 and 2012. Study inclusion began once patients maintained virologic suppression for 12 months (defined as baseline). We examined age and baseline CD4/CD8 ratio and used Cox proportional hazard models to assess baseline CD4/CD8 ratio and NCDs.

RESULTS

This study included 2006 patients. Low baseline CD4/CD8 ratio was associated with older age, male sex, and low CD4 lymphocyte counts. In models adjusting for CD4 lymphocyte count, CD4/CD8 ratio was inversely associated with age (P < 0.01). Among all patients, 182 had incident NCDs, including 46 with coronary artery disease (CAD) events. CD4/CD8 ratio was inversely associated with risk of CAD events [adjusted HR per 0.1 increase in CD4/CD8 ratio = 0.87, 95% confidence interval (CI): 0.76-0.99, P = 0.03]. This association was driven by those under age 50 years (adjusted HR 0.83 [0.70-0.97], P = 0.02) vs. those over age 50 years (adjusted HR = 0.96 [0.79-1.18], P = 0.71). CD4/CD8 ratio was not significantly associated with incident noncardiac NCDs.

CONCLUSIONS

Higher CD4/CD8 ratio after 1 year of HIV virologic suppression was independently predictive of decreased CAD risk, particularly among younger adults. Advanced immune senescence may contribute to CAD events in younger HIV patients on antiretroviral therapy.

Higher Levels of Osteoprotegerin and Immune Activation/Immunosenescence Markers Are Correlated with Concomitant Bone and Endovascular Damage in HIV-Suppressed Patients

HIV-infected patients appear to have a significantly greater risk of non-AIDS comorbidities such as osteoporosis and atherosclerosis. Subjects with osteoporosis are at a higher risk of developing cardiovascular disease than those with normal bone mass, therefore a possible relation between these two conditions can be hypothesized. In the setting of HIV infection, several factors might contribute to bone disease and endothelial dysfunction. The aim of our study was to evaluate the relationship between bone and cardiovascular disease and to investigate the role of traditional factors, T-cell phenotype and osteoprotegerin in HIV positive subjects on effective antiretroviral therapy. We included 94 HIV positive subjects on antiretroviral therapy with virological suppression and 41 healthy subjects matched for age and gender as a control group. Carotid-Intima Media Thickness (c-IMT) and bone mineral density (BMD) were performed by ultrasound and DEXA, respectively. CD4+/CD8+ T-cell activation, senescence and osteoprotegerin plasma levels were measured by flow-cytometry and ELISA, respectively. Among HIV positive patients, 56.4% had osteopenia/osteoporosis and 45.7% had pathological c-IMT (>0.9 mm). Subjects with pathological c-IMT and BMD exhibited higher CD4+ and CD8+ activated, CD8+ senescent and osteoprotegerin than subjects with normal c-IMT and BMD. HIV positive subjects with osteopenia/osteoporosis had higher c-IMT than subjects with normal BMD, and linear regression analysis showed a negative correlation between BMD and c-IMT. Several factors are implicated in the pathogenesis of non-AIDS comorbidities in HIV positive patients. Osteoprotegerin together with inflammation and immunosenescence in HIV positive patients could affect bone and vascular system and could be considered as a possible common link between these two diseases.

START or SMART? Timing of Antiretroviral Therapy Initiation and Cardiovascular Risk for People With Human Immunodeficiency Virus Infection

The Initiation of Antiretroviral Therapy in Early Asymptomatic HIV Infection (START) study has reinforced the benefits of early initiation of antiretroviral therapy (ART). However, a notable secondary finding from that study was that immediate initiation of ART did not prevent cardiovascular disease (CVD) events (0.17 vs 0.20 events/1000 person-years, P = .65). This result appears to contradict a body of evidence, most notably from the Strategies for Management of Antiretroviral Therapy (SMART) study, which reported a 70% increased hazard of cardiovascular events for those deferring or interrupting treatment. Thus, an important unresolved question is whether the timing of ART impacts CVD risk. In this review, published data on relationships between timing of ART and CVD risk are reviewed. The data support a role for ART in mitigating CVD risk at lower CD4 counts, but data also suggests that, among those initiating therapy early, ART alone appears to suboptimally mitigate CVD risk. Additional interventions to address CVD risk among human immunodeficiency virus-infected populations are likely to be needed.

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.

Pro-Inflammatory Markers in Relation to Cardiovascular Disease in HIV Infection. A Systematic Review

Background

In the past years many inflammatory markers have been studied in association with clinically manifest cardiovascular disease (CVD) and carotid intima-media thickness (CIMT) in HIV-infected patients, to obtain insights in the increased cardiovascular risk observed in HIV infection. This systematic review provides an oversight of the current knowledge.

Methods

A search was performed in PubMed, Embase and Cochrane in July 2014, identifying all articles from 1996 onwards addressing the relation between inflammatory markers and CVD or CIMT in HIV-positive adults. Two authors, using predefined criteria, independently conducted the selection of articles, critical appraisal and extraction of the data. Analysis was focused on the immune markers that were most frequently assessed. The review protocol was registered in the PROSPERO database at 11 July 2014 (registration number CRD42014010516). This review was performed according to the PRISMA guideline.

Findings

Forty articles were selected; eight addressing cardiovascular disease (CVD) and thirty-two addressing CIMT. C-reactive protein (CRP), interleukin-6 (IL-6) and d-dimer were assessed most frequently in relation to the occurrence of CVD; in four out of eight studies. All three markers were positively related to CVD in three out of four studies. Studies addressing CIMT were too heterogeneous with respect to patient populations, inflammatory markers, CIMT measurement protocols and statistical methods to allow for a formal meta-analysis to obtain summary statistics. CRP, IL-6 and soluble vascular cell adhesion molecule (sVCAM-1) were the most studied markers in relation to CIMT. None of the inflammatory markers showed an association with CIMT.

Interpretation

This review showed a relation between some inflammatory markers and CVD, however, no consistent relation is observed for CIMT. Statistical approaches that yields effect estimates and standardized CIMT protocols should be chosen. Further research should focus on prospective studies and a selected set of inflammatory markers.

Persistent Immune Activation and Carotid Atherosclerosis in HIV-Infected Ugandans Receiving Antiretroviral Therapy

BACKGROUND

Human immunodeficiency virus (HIV) infection and associated immune activation predict the risk of cardiovascular disease in resource-rich areas. Less is known about these relationships in sub-Saharan Africa.

METHODS

Beginning in 2005, we enrolled subjects in southwestern Uganda into a cohort at the time of antiretroviral therapy (ART) initiation. Multiple immune activation measures were assessed before and 6 months after ART initiation. Beginning in 2013, participants aged >40 years underwent metabolic profiling, including measurement of hemoglobin A1c and lipid levels and carotid ultrasonography. We fit regression models to identify traditional and HIV-specific correlates of common carotid intima media thickness (CCIMT).

RESULTS

A total of 105 participants completed carotid ultrasonography, with a median completion time of 7 years following ART initiation. Age, low-density lipoprotein cholesterol level, and pre-ART HIV load were correlated with CCIMT. No association was found between CCIMT and any pre-ART biomarkers of immune activation. However, in multivariable models adjusted for cardiovascular disease risk factors, lower absolute levels of soluble CD14 and interleukin 6 and greater declines in the CD14 level and kynurenine-tryptophan ratio after 6 months of ART predicted a lower CCIMT years later (P < .01).

CONCLUSIONS

Persistent immune activation despite ART-mediated viral suppression predicts the future atherosclerotic burden among HIV-infected Ugandans. Future work should focus on clinical correlates of these relationships, to elucidate the long-term health priorities for HIV-infected people in the region.

HIV-related metabolic comorbidities in the current ART era

Despite effective antiretroviral therapy (ART), HIV-infected individuals have residual chronic immune activation that contributes to the pathogenesis of HIV infection. This immune system dysregulation is a pathogenic state manifested by very low naïve T-cell numbers and increased terminally differentiated effector cells that generate excessive proinflammatory cytokines with limited functionality. Immune exhaustion leaves an individual at risk for accelerated aging-related diseases, including renal dysfunction, atherosclerosis, diabetes mellitus, and osteoporosis. We highlight research that clarifies the role of HIV, ART, and other factors that contribute to the development of these diseases among HIV-infected persons.

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.

Relationships of pulmonary function, inflammation, and T-cell activation and senescence in an HIV-infected cohort

OBJECTIVE

To determine associations between circulating markers of immune activation, immune cell senescence, and inflammation with HIV-associated abnormalities of pulmonary function.

DESIGN

HIV infection is an independent risk factor for abnormal pulmonary function. Immune activation, immune senescence, and chronic inflammation are characteristics of chronic HIV infection that have been associated with other HIV-associated comorbidities and may be related to pulmonary disease in this population.

METHODS

Participants from an HIV-infected cohort (n = 147) completed pulmonary function testing (PFT). Markers of T-cell activation and senescence were determined by flow cytometry, and plasma levels of interleukin-6, interleukin-8, and C-reactive protein (CRP) were measured, as was telomere length of peripheral blood mononuclear cells (PBMC). Regression models adjusting for clinical risk factors were constructed to examine relationships between biomarkers and PFT outcomes.

RESULTS

Activated CD25(+) T cells and activated/senescent CD69(+)/CD57(+)/CD28(null) CD4(+) T cells, interleukin-6, and CRP were associated with PFT abnormalities. Shortening of PBMC telomere length correlated with airflow obstruction and diffusing impairment. Paradoxically, circulating senescent CD57(+)/CD28(null) CD8(+) T cells were associated with better PFT outcomes.

CONCLUSION

Circulating T cells expressing markers of activation and inflammatory cytokine levels are independently correlated with PFT abnormalities in HIV-infected persons. Overall telomere shortening was also associated with pulmonary dysfunction. The paradoxical association of senescent CD8(+) T cells and better PFT outcomes could suggest an unrecognized beneficial compensatory function of such cells or a redistribution of these cells from the circulation to local compartments. Further studies are needed to differentiate and characterize functional subsets of local pulmonary and circulating T-cell populations in HIV-associated pulmonary dysfunction.

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.

Invariant natural killer T (iNKT) cells in HAART-treated, HIV-positive patients with bone and cardiovascular impairment

Background

Invariant Natural Killer T (iNKT) cells represent a determinant in the course of infections and diseases, however, their role in the pathogenesis of non-infectious co-morbidities in HIV-positive patients is unknown.

Methods

Flow cytometry was used to investigate iNKT cell frequency, phenotype and function in HIV-infected patients on HAART with bone and/or cardiovascular disorders and in HIV-positive controls free from co-morbidities.

Results

iNKT cells from subjects with bone and cardiovascular impairment expressed high levels of CD161 and predominantly secreted TNF. iNKT cells from individuals with bone disease alone did not show any distinctive phenotypical or functional characteristics. The functional capacity of iNKT cells in patients with cardiovascular disorder was impaired with no cytokine release upon stimulation.

Conclusion

iNKT cells may have a role in non-infectious co-morbidities in treated HIV disease, possibly through the exacerbation of inflammation. Further studies are needed to investigate iNKT cells in the pathogenesis of non-communicable disorders in HIV infection.

Immune activation, immunosenescence, and osteoprotegerin as markers of endothelial dysfunction in subclinical HIV-associated atherosclerosis

HIV-infected patients have a significantly greater risk of cardiovascular disease. Several markers including osteoprotegerin have been shown to be involved in the development and progression of atherosclerosis. We investigated the relationship between T-cell phenotype, osteoprotegerin, and atherosclerosis evaluated by carotid intima-media thickness (c-IMT) in 94 HIV+ patients on suppressive antiretroviral therapy with Framingham score <10%. As for the control group, 24 HIV-negative subjects were enrolled. c-IMT was assessed by ultrasound. CD4+/CD8+ T-cell activation (CD38+ HLADR+) and senescence (CD57+ CD28−) were measured by flow cytometry. IL-6 and OPG levels were measured by ELISA kit. c-IMT was higher in HIV+ than in controls. Among HIV+ patients, 44.7% had pathological c-IMT (≥0.9 mm). CD8+ T-cell activation and senescence and OPG plasma levels were higher in HIV+ patients than in controls. Subjects with pathological c-IMT exhibited higher CD8+ immune activation and immunosenescence and OPG levels than subjects with normal c-IMT. Multivariate analysis showed that age, CD8+ CD38+ HLADR+, and CD8+ CD28− CD57+ were independently associated with pathological c-IMT. Several factors have been implicated in the pathogenesis of atherosclerosis in HIV patients. Immune activation and immunosenescence of CD8+ T cell together with OPG plasma levels might be associated with the development and progression of early atherosclerosis, even in the case of viral suppression.

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.

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.

Cytomegalovirus coinfection is associated with an increased risk of severe non-AIDS-defining events in a large cohort of HIV-infected patients

BACKGROUND

Chronic cytomegalovirus (CMV) infection has been associated with immunosenescence and immunoactivation in the general population. In human immunodeficiency virus type 1 (HIV-1)-infected people, CMV coinfection, in addition to residual HIV replication and microbial translocation, has been proposed as a key factor in sustaining immune activation, even in individuals with a controlled HIV load.

METHODS

Patients from the ICONA Study with at least 1 CMV immunoglobulin G (IgG) test available without active CMV disease were included in the analysis. AIDS-defining event or AIDS-related death and severe non-AIDS-defining event or non-AIDS-related death were taken as clinical progression end points. Independent predictors of CMV were identified by multivariable logistic regression. Probabilities of reaching the end points were estimated by survival analyses.

RESULTS

A total of 6111 subjects were included, of whom 5119 (83.3%) were CMV IgG positive at baseline. Patients with CMV IgG positivity at baseline were more likely to develop a severe non-AIDS-defining event/non-AIDS-related death (adjusted hazard ratio [HR], 1.53 [95% confidence interval {CI}, 1.08-2.16]. In particular, CMV seropositivity was an independent risk factor for cardiovascular and cerebrovascular diseases (adjusted HR, 2.27 [95% CI, .97-5.32]).

CONCLUSIONS

In our study population, CMV/HIV coinfection was associated with the risk of severe non-AIDS-defining events/non-AIDS-related death, especially with cardiovascular and cerebrovascular events, independently of other prognostic factors. This finding supports a potential independent role of CMV coinfection in vascular/degenerative organ disorders in HIV-infected subjects.