Biomarkers of microbial translocation and macrophage activation: association with progression of subclinical atherosclerosis in HIV-1 infection

Inflammatory and cardiovascular diseases biomarkers in chronic hepatitis C virus infection: A review

Hepatitis C virus (HCV) infects 180 million people worldwide and over 4 million people in the United States. HCV infection is a major cause of chronic liver disease and is recognized as a risk factor for clinical cardiovascular disease (CVD). Many studies have shown increased prevalence of cardiac and inflammatory biomarkers in patients with chronic HCV infection (CHC), and though these markers may be used to risk stratify people for cardiac disease in the general population their role in the HCV population is unknown. Patients with CHC have elevated cardiac and inflammatory biomarkers compared to noninfected controls which may play a role in CVD risk stratification. We undertook a systematic review of inflammatory and cardiac biomarkers in people with HCV infection with a focus on the effect of CHC on serum levels of these markers and their utility as predictors of CVD in this population. Medline, EMBASE, and Cochrane databases were searched for relevant articles until June 2019. A total of 2430 results were reviewed with 115 studies included. Our review revealed that HCV infection significantly alters serum levels of markers of inflammation, endothelial function, and cardiac dysfunction prior to HCV treatment, and some of which may change in response to HCV therapy. Current risk stratification tools for development of CVD in the general population may not account for the increased inflammatory markers that appear to be elevated among HCV‐infected patients contributing to increased CVD risk.

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.

Frailty Is an Independent Risk Factor for Mortality, Cardiovascular Disease, Bone Disease, and Diabetes Among Aging Adults With Human Immunodeficiency Virus

BACKGROUND

We characterized associations between frailty and incident cardiovascular disease (CVD), diabetes mellitus (DM), bone disease, and mortality within a cohort of aging persons with human immunodeficiency virus (PWH).

METHODS

Participants underwent frailty evaluations using the Fried frailty assessment (baseline and annually). Frailty was defined as having ≥3 frailty criteria. Clinical outcomes of mortality, CVD events, DM, and bone disease events were recorded throughout the study period (baseline to most recent study or clinic visit, or date of clinical outcome, whichever came first). Poisson regression models were used to evaluate associations between baseline frailty, change in frailty score over 48 weeks, and each clinical outcome.

RESULTS

Among 821 men and 195 women (median age 51 years), 62 (6%) were frail at baseline. Frailty scores increased by ≥1 component among 194 participants (19%) from baseline to 48 weeks. Baseline frailty was associated with an increased risk of incident CVD and DM, with a trend toward a significant association with bone events. Among frailty components, slow gait speed was associated with incident DM and borderline associated with incident CVD. An increase in frailty from baseline to week 48 was associated with mortality but not with the other clinical outcomes.

CONCLUSIONS

Baseline frailty was associated with multiple adverse health outcomes (incident CVD, DM, and bone disease), while increase in frailty score was associated with mortality among PWH engaged in care. Incorporation of frailty assessments into the care of PWH may assist in improvement of functional status and risk stratification for age-related chronic diseases.

Subclinical Atherosclerosis Imaging in People Living with HIV

In many, but not all studies, people living with HIV (PLWH) have an increased risk of coronary artery disease (CAD) events compared to the general population. This has generated considerable interest in the early, non-invasive detection of asymptomatic (subclinical) atherosclerosis in PLWH. Ultrasound studies assessing carotid artery intima-media thickness (CIMT) have tended to show a somewhat greater thickness in HIV+ compared to HIV−, likely due to an increased prevalence of cardiovascular (CV) risk factors in PLWH. Coronary artery calcification (CAC) determination by non-contrast computed tomography (CT) seems promising to predict CV events but is limited to the detection of calcified plaque. Coronary CT angiography (CCTA) detects calcified and non-calcified plaque and predicts CAD better than either CAC or CIMT. A normal CCTA predicts survival free of CV events over a very long time-span. Research imaging techniques, including black-blood magnetic resonance imaging of the vessel wall and 18F-fluorodeoxyglucose positron emission tomography for the assessment of arterial inflammation have provided insights into the prevalence of HIV-vasculopathy and associated risk factors, but their clinical applicability remains limited. Therefore, CCTA currently appears as the most promising cardiac imaging modality in PLWH for the evaluation of suspected CAD, particularly in patients <50 years, in whom most atherosclerotic coronary lesions are non-calcified.

Mass Cytometry Reveals the Immaturity of Circulating Neutrophils during SIV Infection

The infected host fails to eradicate HIV-1, despite significant control of viral replication by combinational antiretroviral therapy. Here, we assessed the impact of HIV infection on immune-cell compartments in a SIVmac251 nonhuman primate infection model, which allowed the choice of contamination route, time of infection, and treatment follow-up. We performed high-throughput multiparameter single-cell phenotyping by mass cytometry to obtain a global vision of the immune system in blood and bone marrow. Circulating polymorphonuclear neutrophils (PMNs) with impaired phagocytosis had altered surface expression of CD62L and CD11b during early chronic infection. The initiation of combinational antiretroviral treatment during primary infection did not restore PMN function. The maturation state of PMNs was highly altered during late chronic SIV infection, showing a primarily immature phenotype. Our results provide new insights into PMN involvement in the pathogenesis of HIV infection and may play a role in the establishment and maintenance of chronic immune activation.

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.

HIV-exposed-uninfected infants have increased inflammation and monocyte activation

BACKGROUND

HIV-exposed-uninfected (HEU) infants have increased infectious morbidity and mortality; little is known about their levels of inflammation and monocyte activation.

METHODS

Plasma samples obtained at birth and 6 months from 86 HEU mother-infant pairs enrolled in the National Institute of Child Health and Human Development cohorts in Brazil were compared with 88 HIV-unexposed mother-infant pairs. HIV-infected mothers received antiretroviral therapy during pregnancy, their infants received zidovudine prophylaxis and were not breastfed. IL-6, soluble TNFα receptor I (sTNF-RI) and II, soluble CD14, soluble CD163, IFN-γ-induced protein 10 (IP-10), vascular cell adhesion molecule, oxidized LDL, D-dimer and high-sensitivity C-reactive protein were assayed by ELISA at birth and at 6 months. sTNF-RI and IL-6 were considered coprimary endpoints.

RESULTS

Among HIV-infected mothers, 79% had HIV-RNA less than 400 copies/ml prior to delivery. Compared with HIV-unexposed, HEU infants had a lower mean gestational age (38.7 vs. 39.3 weeks) and weight (3.1 vs. 3.3 kg); and reached lower weight (5.9 vs. 8.5 kg) and height (53.6 vs. 68.8 cm) at 6 months. With the exception of vascular cell adhesion molecule, inflammatory markers were generally higher (P ≤ 0.005) in HEU at birth, but at 6 months only sTNF-RI and IL-6 remained higher. For HEU pairs, only IP-10 was associated with maternal levels at birth (P < 0.001). In HEU, elevated levels of high-sensitivity C-reactive protein and IP-10 at birth were associated with lower weight at birth (P = 0.04) and at 6 months (P = 0.04).

CONCLUSION

HIV-exposed infants have heightened inflammation and monocyte activation at birth, which for some markers persisted to 6 months of life and was not related to maternal inflammatory status. Inflammation may contribute to the increased HEU infectious morbidity and poor growth.

CD16-expressing monocytes correlate with arterial stiffness in HIV-infected ART-naïve men

Objectives To determine the association of the markers of monocyte activation and arterial stiffness among HIV-infected antiretroviral therapy (ART)-naïve men. Methods Sixty HIV-infected ART-naïve men and 20 HIV-uninfected male controls without symptoms or history of cardiovascular disease were recruited. Pulse wave velocity (PWV) were used as the marker of arterial stiffness and determined using a pulse pressure analyzer. The percentage of CD16-expressing monocytes was used as a marker of monocyte activation. Plasma neopterin concentration, one of the monocyte/macrophage activation markers and plasma tissue factor (TF), the coagulation marker in response to inflammatory stimuli, were also analyzed. Multivariate analyses were used to explore the association of the percentage of CD16-expressing monocytes with arterial stiffness in HIV-infected men. Results HIV-infected ART-naïve men demonstrated significantly higher PWV (1252.8 ± 161.6 vs.1159.2 ± 108.3 cm/s, p = 0.018). The percentage of CD16-expressing monocytes was significantly higher in HIV-infected men comparing male controls (23.4 ± 6.0% vs. 19.6 ± 4.6%, p = 0.012). Plasma concentrations of neopterin (0.91 vs. 0.64 ng/ml), p < 0.001) and TF (5.29 vs. 4.43 pg/ml, p = 0.04) were higher in HIV-infected men comparing controls. In the multivariate model for PWV among HIV-infected men, the percentage of CD16-expressing monocytes (p = 0.023) and age (p = 0.017) were significantly associated with PWV. HIV viral load, CD4 count, percentage of CD8+CD38+T cells and percentage of CD8+HLA-DR+ T cells were not associated with PWV. Discussion Higher level of monocyte activation marker is associated with higher level of arterial stiffness in ART naïve HIV-infected men. HIV viral load, CD4 count, and the markers of CD8 T cell activation were unrelated to PWV.

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.

Diet Quality Is Low and Differs by Sex in People with HIV

Background

People with HIV (PWH) are at risk for developing metabolic comorbidities driven, in part, by immune activation/inflammation. Little is known about diet quality, a potential modifiable factor in PWH.

Objectives

This study aimed to explore diet quality in terms of conformance with US dietary guidelines by calculating Healthy Eating Index-2010 (HEI) scores among adults with and without HIV in Boston, MA, and determine associations with HEI and markers of immune activation/inflammation.

Methods

One-hundred and three HIV-infected [50 women, 53 men; mean ± SD age: 47 ± 7 y; body mass index (BMI, in kg/m2): 26 ± 5] and 38 uninfected adults (17 women, 21 men; age: 46 ± 7 y; BMI: 28 ± 4) were included in this cross-sectional analysis. Participants who completed a 4-d food record from which HEI could be calculated were included. HEI was compared between participants with and without HIV, within HIV-infected participants stratified by sex, and by HIV serostatus and sex. In the HIV group, predictors of HEI were determined in multivariable modeling. Univariate associations with diet quality and inflammation/immune markers were assessed.

Results

The HEI score was 51.3 in the HIV-infected participants and 57.3 in the HIV-uninfected participants (P = 0.052). In the comparison by HIV serostatus and sex, HIV-infected women had significantly lower HEI (49.2) compared with HIV-infected men (55.7) (P = 0.005) and HIV-uninfected men (61.8) (P = 0.002). Adjusting for potential confounding factors, sex remained an independent predictor of HEI in HIV (P = 0.02). In the HIV group, higher log HEI was associated with lower concentration of the immune activation marker sCD14 (P = 0.009).

Conclusions

Diet quality tended to be lower in HIV-infected individuals compared with HIV-uninfected individuals and was lower among HIV-infected women compared with HIV-infected men, and HIV-uninfected men. There may also be an association with diet quality and sCD14 in PWH. Future prospective studies are needed to confirm these findings and determine whether improving diet quality is a useful strategy to reduce metabolic abnormalities in this population. This study was registered at clinicaltrials.gov as NCT00455793.

HIV-associated cardiovascular disease: importance of platelet activation and cardiac fibrosis in the setting of specific antiretroviral therapies

HIV infection is a risk factor for cardiovascular disease (CVD). This risk is accentuated by certain combination antiretroviral therapies (cARTs), independent of their effects on lipid metabolism and insulin sensitivity. We sought to define potential mechanisms for this association through systematic review of clinical and preclinical studies of CVD in the setting of HIV/cART from the English language literature from 1989 to March 2018. We used PubMed, Web of Knowledge and Google Scholar, and conference abstracts for the years 2015-March 2018. We uncovered three themes: (1) a critical role for the HIV protease inhibitor (PI) ritonavir and certain other PI-based regimens. (2) The importance of platelet activation. Virtually all PIs, and one nucleoside reverse transcriptase inhibitor, abacavir, activate platelets, but a role for this phenomenon in clinical CVD risk may require additional postactivation processes, including: release of platelet transforming growth factor-β1; induction of oxidative stress with production of reactive oxygen species from vascular cells; suppression of extracellular matrix autophagy; and/or sustained proinflammatory signalling, leading to cardiac fibrosis and dysfunction. Cardiac fibrosis may underlie an apparent shift in the character of HIV-linked CVD over the past decade from primarily left ventricular systolic to diastolic dysfunction, possibly driven by cART. (3) Recognition of the need for novel interventions. Switching from cART regimens based on PIs to contemporary antiretroviral agents such as the integrase strand transfer inhibitors, which have not been linked to clinical CVD, may not mitigate CVD risk assumed under prior cART. In conclusion, attention to the effects of specific antiretroviral drugs on platelet activation and related profibrotic signalling pathways should help: guide selection of appropriate anti-HIV therapy; assist in evaluation of CVD risk related to novel antiretrovirals; and direct appropriate interventions.

Fractures and the gut microbiome

PURPOSE OF REVIEW

The role of the gut microbiome in the pathogenesis of several inflammatory, non-AIDS comorbidities, such as cardiovascular disease, cognitive impairment and liver disease has become a focus of recent research. Low bone mineral density (BMD) and increased fracture incidence in people living with HIV (PLWH) is also widely reported, however, the relationship between alterations in the gut microbiome and bone disease in PLWH has not been previously reviewed.

RECENT FINDINGS

Murine models that manipulate the gut microbiome, either through breeding of 'germ-free' mice or antibiotic-depleted gut microbiome, show differences in bone mineral density and bone mass in those with altered gut microbiome. This effect is reported to be driven via changes in the gut-immune-skeletal axis, with changes favouring bone resorption. Several inflammatory conditions wherever bone loss is a prominent feature, such as rheumatoid arthritis and inflammatory bowel disease, have also reported alterations in the gut microbiome, which are associated with bone loss, again through changes in the gut-immune-skeletal axis.

SUMMARY

The interplay between the gut microbiome and the immune-skeletal axis in HIV represents a complex relationship. Alterations in the gut microbiome, which induce an activated immune phenotype and inflammatory milieu are associated with non-AIDS comorbidities in PLWH and bone loss in several other conditions characterized by chronic immune activation and inflammation. It is, therefore, likely that there are comparable effects between altered gut microbiome and bone loss in HIV, however, further research is required to better define this relationship in populations of PLWH.

Cardiovascular disease risk among women living with HIV in North America and Europe

PURPOSE OF REVIEW

To examine the epidemiology and mechanistic underpinnings of heightened cardiovascular disease (CVD) risk among women living with HIV (WLHIV) in North America and Europe.

RECENT FINDINGS

WLHIV in North America and Europe exhibit high CVD incidence rates, which are at par with those of compatriot men living with HIV. Compared with uninfected women, WLHIV in these regions face a 2-4-fold increased relative risk for myocardial infarction, stroke, and heart failure. HIV-associated CVD risk is fuelled by a negative synergy of traditional cardiometabolic risk factors and heightened systemic immune activation/inflammation. Among WLHIV, female sex and endogenous sex hormone production influence both traditional cardiometabolic risk factors and patterns of systemic immune activation/inflammation. WLHIV in North America and Europe may also experience heightened CVD risk in relation to a relatively increased prevalence of behavioral and psychosocial CVD risk factors, coupled with suboptimal therapeutic targeting of known traditional cardiometabolic risk factors.

SUMMARY

Additional research on sex-specific mechanisms of HIV-associated CVD - based not only out of North America and Europe but also and especially out of Africa, Asia, and South America - will inform the development of CVD prediction algorithms and prevention guidelines clinically relevant to the approximately 17 million women aging with HIV globally.

The Cholinergic Anti-Inflammatory Response and the Role of Macrophages in HIV-Induced Inflammation

Macrophages are phagocytic immune cells that protect the body from foreign invaders and actively support the immune response by releasing anti- and proinflammatory cytokines. A seminal finding revolutionized the way macrophages are seen. The expression of the neuronal alpha7 nicotinic acetylcholine receptor (α7-nAChR) in macrophages led to the establishment of the cholinergic anti-inflammatory response (CAR) in which the activation of this receptor inactivates macrophage production of proinflammatory cytokines. This novel neuroimmune response soon began to emerge as a potential target to counteract inflammation during illness and infection states. Human immunodeficiency virus (HIV)-infected individuals suffer from chronic inflammation that persists even under antiretroviral therapy. Despite the CAR’s importance, few studies involving macrophages have been performed in the HIV field. Evidence demonstrates that monocyte-derived macrophages (MDMs) recovered from HIV-infected individuals are upregulated for α7-nAChR. Moreover, in vitro studies demonstrate that addition of an HIV viral constituent, gp120_IIIB, to uninfected MDMs also upregulates the α7-nAChR. Importantly, contrary to what was expected, activation of upregulated α7-nAChRs in macrophages does not reduce inflammation, suggesting a CAR disruption. Although it is reasonable to consider this receptor as a pharmacological target, additional studies are necessary since its activity seems to differ from that observed in neurons.

Insulin-like growth factor 1 inversely relates to monocyte/macrophage activation markers in HIV

OBJECTIVE

Monocyte/macrophage activation is increased among people with HIV, and may contribute to the heightened risk of atherosclerosis and neurocognitive dysfunction in this population. Insulin-like growth factor 1 (IGF-1) has been shown to attenuate the innate immune response in animal models of atherosclerosis and inflammatory bowel disease. We investigated, for the first time, relationships of circulating IGF-1 with monocyte/macrophage-specific indices among HIV-infected individuals and uninfected controls.

DESIGN

Observational.

METHODS

One hundred and thirty-one HIV-infected patients and 65 well matched controls without known cardiac disease or viral hepatitis were recruited previously. IGF-1, expressed as a z-score relative to the age-adjusted and sex-adjusted population mean, was related to log-transformed inflammatory markers within HIV and non-HIV groups.

RESULTS

In HIV, IGF-1 inversely related to sCD163 (r = -0.28, P = 0.002), sCD14 (r = -0.29, P = 0.002), and high-sensitivity IL-6 (r = -0.27, P = 0.006). There was no association of IGF-1 with high-sensitivity CRP, MCP-1, IL-18, or LPS in HIV, or between IGF-1 and any inflammatory marker in controls. Relationships of IGF-1 with sCD163 and sCD14 remained significant in HIV after controlling for age, sex, smoking, BMI, visceral fat, statin use, viral load, and antiretroviral therapy. For every one-unit decline in IGF-1 z-score, sCD163 and sCD14 increased by 14% (95% CI, 0.23-29%) and 29% (95% CI, 1.4-63%), respectively.

CONCLUSION

Low IGF-1 was robustly associated with high sCD163 and sCD14 in HIV. Prospective studies are needed to investigate augmentation of IGF-1 as a novel strategy to reduce monocyte/macrophage activation in this population.

Caspase-1-associated immune activation in an accelerated SIV-infected rhesus macaque model

In the antiretroviral therapy (ART) era, chronic HIV infection is primarily associated with chronic inflammation driving comorbidities such as cardiovascular disease and neurocognitive impairment. Caspase-1 activation in leukocytes has been documented in HIV infection; however, whether caspase-1 activation and the downstream pro-inflammatory cytokines interleukin-1beta (IL-1β) and interleukin-18 (IL-18) contribute to chronic inflammation in HIV comorbidities remains undetermined. The relationship between the caspase-1 cascade and persistent inflammation in HIV has not been investigated. Here, we used an accelerated simian immunodeficiency virus (SIV)-infected rhesus macaque model with or without ART to investigate the dynamics of caspase-1 and immune cell activation before infection, 21 days post infection (dpi), and necropsy. Caspase-1, IL-18, IL-1β, and immune markers were measured both in the circulation and lymphoid tissues. We found a significant increase in caspase-1 and IL-18 in SIV infection that positively correlated with inflammatory monocytes and negatively correlated with CD4⁺ T cell counts. ART attenuated these effects at necropsy in the circulation. Further, lymph nodes from SIV+ or SIV+ART animals had increased activation of caspase-1 and potential upstream priming of the NF-κB pathway, indicating that tissue-specific immune activation persists with ART. Together, these results shed light on the interconnectedness of the caspase-1 pathway and peripheral immune activation and further indicate that ART is not sufficient for suppressing inflammation. The caspase-1 pathway may provide novel therapeutic targets to improve HIV-associated comorbidities and health outcomes in the context of viral suppression.

Substance-associated elevations in monocyte activation among methamphetamine users with treated HIV infection

OBJECTIVE

Microbial translocation and monocyte activation predict mortality in treated HIV. We examined whether substance use independently contributes to these pathophysiologic processes.

DESIGN

Cross-sectional study at baseline for a randomized controlled trial.

METHODS

HIV-positive, methamphetamine-using MSM with undetectable HIV viral load (less than 40 copies/ml) were enrolled. We examined if plasma biomarkers of monocyte activation and intestinal barrier integrity were associated with the following: reactive urine toxicology results (Tox+) for stimulants (i.e., methamphetamine or cocaine) and substance use severity measured by the Addiction Severity Index. Multiple linear regression models adjusted for age, antiretroviral therapy regimen, CD4 T-cell count, interleukin-6, and alcohol use severity.

RESULTS

The sample of 84 virally suppressed MSM had a median CD4 T-cell count of 645 cells/μl. Those who were Tox+ for stimulants displayed higher soluble CD14 (sCD14) levels (2087 versus 1801 ng/ml; P = 0.009), and this difference remained significant after adjusting for covariates (standardized beta = 0.23, P = 0.026). Greater substance use severity was also independently associated with higher sCD14 after adjusting for covariates (standardized beta = 0.29, P = 0.013). Being Tox+ for stimulants and substance use severity were not associated with soluble CD163 (sCD163) or intestinal fatty acid binding protein (iFABP) levels (P > 0.05).

CONCLUSIONS

Monocyte activation is one plausible mechanism by which stimulant use may increase clinical HIV progression.

Plasma levels of lipopolysaccharide correlate with insulin resistance in HIV patients

BACKGROUND

In HIV patients using HAART insulin resistance is a central pathophysiological condition that can contribute to the development of diabetes and cardiovascular complications. To examine the role of adipocyte hormones and LPS in insulin resistance in HIV patients, we investigated the role of adiponectin, leptin, visfatin and LPS levels in the insulin resistance of HIV-infected patients treated with HAART.

METHODS

This study included 67 HIV positive individuals on HAART and ten healthy controls. All participants performed plasma or serum levels of glucose; insulin; lipids, visfatin, leptin, adiponectin, and LPS. The homeostasis model assessment (HOMA-IR), was used to estimate insulin resistance.

RESULTS

The levels of visfatin, leptin and adiponectin were similar between controls and HIV patients. However, circulating levels of LPS were higher in HIV patients on HAART than in controls. There was a positive correlation between LPS and TG (r = 0.49, p = 0.0001), between LPS and TG/HDL (r = 0.50, p = 0.0001), between LPS and insulin (r = 0.52, p = 0.0003), and between LPS and HOMA-IR (r = 0.52, p = 0.0005), in HIV patients.

CONCLUSIONS

Our results showed a clear correlation between plasma LPS and markers of insulin resistance, suggesting a relationship between LPS levels and metabolic alterations, particularly affecting lipids and insulin resistance in HIV patients.

Atherosclerotic Cardiovascular Disease and Anti-Retroviral Therapy

In the current era of available therapy for human immunodeficiency virus (HIV), life expectancy for persons living with HIV (PLWH) nears that of the general population. Atherosclerotic cardiovascular disease (ASCVD) has become a particular burden for PLWH and society at large. PLWH have historically been shown to have an excess of cardiovascular risk and subsequent events when compared to the general population. Potential explanations include the increased prevalence of traditional risk factors, direct inflammatory and immunological effects from the HIV virus itself, and metabolic adverse effects of anti-retroviral therapy (ART). Over the past few years, there has been building evidence that chronic inflammation and immune activation independent of virologic suppression contribute significantly to excess ASCVD risk. Although independent agents and combination therapies have varying metabolic effects, the evidence from major randomized controlled trials (RCTs) supports the benefits of early initiation of ART. In this review, we will discuss the epidemiology of ASCVD in HIV-infected patients compared with the general population, give an overview of potential pathogenesis of high-risk plaque in HIV-infected patients, discuss different metabolic effects of individual anti-retrovirals, and discuss the limitations in current screening models for assessing cardiovascular disease (CVD) risk and future directions for treatment.

Sex Differences in Select Non-communicable HIV-Associated Comorbidities: Exploring the Role of Systemic Immune Activation/Inflammation

PURPOSE OF THE REVIEW

The goals of this review are to (1) explore HIV-associated cardiovascular disease (CVD), neurocognitive impairment, and non-AIDS-defining cancers (NADC) as heterogeneous model disease states fuelled in part by systemic immune activation/inflammation; (2) consider sex differences in the epidemiology of these diseases in both high-resource and lower-resource settings; and (3) examine biological and environmental factors which may contribute to heightened systemic immune activation/inflammation specifically among women living with HIV (WLHIV).

RECENT FINDINGS

The observation that WLHIV have higher levels of systemic immune activation/inflammation than men living with HIV (MLHIV) may be relevant to sex differences in select non-communicable HIV-associated comorbidities. Heightened systemic immune activation among WLHIV may be influenced by sex-specific responses to the virus and to immunomodulatory agents, as well as by behavioral choices/comorbid conditions and perturbations in the hypothalamic-pituitary-gonadal axis. Additional research is needed to elucidate region-specific drivers of heightened systemic immune activation/inflammation among WLHIV and to determine whether WLHIV who present with one immune-mediated HIV-associated comorbidity (e.g., cognitive impairment) may be at increased risk for another (e.g., CVD, NADC). This kind of research would facilitate improved risk prediction for non-communicable HIV-associated comorbidities among WLHIV and the development of targeted immunomodulatory prevention strategies.

HDL Cholesterol Efflux Capacity in Newly Diagnosed HIV and Effects of Antiretroviral Therapy

CONTEXT

In the general population, high-density lipoprotein (HDL) cholesterol efflux capacity (HCEC) relates inversely to incident cardiovascular events. Previous studies have suggested that HCEC is decreased in HIV and that antiretroviral therapy (ART) initiation might improve HCEC.

OBJECTIVE

To evaluate HCEC in the context of ART initiation and immune activation in HIV.

DESIGN AND OUTCOME MEASURES

Baseline HCEC from 10 ART-naive HIV-infected males and 12 prospectively matched non-HIV-infected males were analyzed. In the HIV cohort, HCEC 6 months after elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (E/C/F/TDF) therapy was evaluated. HCEC served as the primary outcome and was measured by the ability of J774 mouse macrophages to efflux cholesterol. Our ex vivo assay used two cholesterol acceptors [apolipoprotein B (apoB)-depleted sera or purified HDL] and modulation of cellular efflux pathways using a liver X receptor (LXR) agonist.

RESULTS

The median age was 34 years [interquartile range (IQR), 27 to 51], and baseline HDL was 46 mg/dL (IQR, 38 to 61). HCEC was significantly greater in the non-HIV-infected subjects than in the HIV-infected subjects at baseline. HCEC, assessed using apoB-depleted sera, significantly increased after ART (no LXR agonist, baseline: median, 8.1%; IQR, 7.0% to 11.9%; after ART: median, 12.9%; IQR, 10.4% to 21.1%; P = 0.006; LXR agonist, baseline, 1.3% ± 1.3%; after ART, 2.5% ± 1.0%; P = 0.02), although not to the levels in the non-HIV-infected subjects (no LXR agonist: median, 14.9%; IQR, 11.5% to 19.1%; LXR agonist: 5.8% ± 1.3%). HCEC, assessed using purified HDL, did not significantly increase after ART. The change in HCEC with ART related inversely to the change in the percentage of CD14-CD16+ (nonclassical) monocytes (ρ = -0.74, P = 0.04) and directly to the change in the percentage of CD14+CD16- (classical) monocytes (ρ = 0.72, P = 0.045).

CONCLUSIONS

Our data suggest improvement of HCEC with E/C/F/TDF and a relationship between the ART-induced decrease in immune activation and ART-induced improvement in HCEC.

Inflammation, Immune Activation, and Antiretroviral Therapy in HIV

PURPOSE OF REVIEW

This review focuses on the differential effects of contemporary antiretrovirals on systemic inflammation as heightened immune activation is linked to important co-morbidities and mortality with HIV infection.

RECENT FINDINGS

Antiretroviral therapy (ART) reduces dramatically systemic inflammation and immune activation, but not to levels synchronous with HIV-uninfected populations. In one ART initiation trial, integrase inhibitors appear to reduce inflammation to a greater degree than non-nucleoside reverse transcriptase inhibitors (NNRTIs); however, it is not clear that there are beneficial effects on inflammation resulting from treatment with integrase inhibitors compared to PIs, between PIs and NNRTIs, between specific nucleoside reverse transcriptase inhibitors, or with maraviroc in ART-naïve patients. In ART switch studies, changing to an integrase inhibitor from a PI-, NNRTI-, or enfuvirtide-containing regimen has resulted in improvement in several markers of inflammation. Additional research is needed to conclusively state whether there are clear differences in effects of specific antiretrovirals on inflammation and immune activation in HIV.

The clinical implications of HIV infection and aging

The objectives of this study, presented as part of a plenary session at WW7 in Hyderabad, India were to review (i) the epidemiology and current clinical issues of HIV infection with regard to HIV and older populations and (ii) models for increased morbidity and mortality in older HIV-positive individuals with implications for clinical care. HIV infection for those in treatment has become a complex chronic disease in which end-organ injury and resulting morbidity, functional decline, and mortality do not have a single etiology but reflect cumulative loss of organ system reserve from multiple interacting sources leading to functional decline, organ system failure, and death. Emerging guidelines and recommendations suggest a need for increased awareness and treatment of the multifaceted needs of the aging HIV-infected patient.

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.

Insulin Resistance and Markers of Inflammation in HIV-infected Ugandan Children in the CHAPAS-3 Trial

BACKGROUND

Few studies have investigated metabolic complications in HIV-infected African children and their relation with inflammation.

METHODS

We compared baseline and changes in insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR)] and in markers of inflammation over 48 weeks, in a subset of antiretroviral therapy (ART)-naive Ugandan children from the Children with HIV in Africa-Pharmacokinetics and Adherence/Acceptability of Simple Antiretroviral Regimens trial randomized to zidovudine-, stavudine- or abacavir (ABC)-based regimen. Nonparametric methods were used to explore between-group and within-group differences, and multivariable analysis to assess associations of HOMA-IR.

RESULTS

One-hundred eighteen children were enrolled, and median age (interquartile range) was 2.8 years (1.7-4.3). Baseline median HOMA-IR (interquartile range) was 0.49 (0.38-1.07) and similar between the arms. At week 48, median relative changes in HOMA-IR were 14% (-29% to 97%) in the zidovudine arm, -1% (-30% to 69%) in the stavudine arm and 6% (-34% to 124%) in the ABC arm (P ≤ 0.03 for all the arms compared with baseline, but P = 0.90 for between-group differences). Several inflammation markers significantly decreased in all study arms; soluble CD14 increased on ABC and did not change in the other 2 arms. In multivariate analysis, only changes in soluble CD163 were positively associated with HOMA-IR changes.

CONCLUSIONS

In ART-naive Ugandan children, HOMA-IR changed significantly after 48 weeks of ART and correlated with monocyte activation.

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.

Macrophages and Phospholipases at the Intersection between Inflammation and the Pathogenesis of HIV-1 Infection

Persistent low grade immune activation and chronic inflammation are nowadays considered main driving forces of the progressive immunologic failure in effective antiretroviral therapy treated HIV-1 infected individuals. Among the factors contributing to this phenomenon, microbial translocation has emerged as a key driver of persistent immune activation. Indeed, the rapid depletion of gastrointestinal CD4⁺ T lymphocytes occurring during the early phases of infection leads to a deterioration of the gut epithelium followed by the translocation of microbial products into the systemic circulation and the subsequent activation of innate immunity. In this context, monocytes/macrophages are increasingly recognized as an important source of inflammation, linked to HIV-1 disease progression and to non-AIDS complications, such as cardiovascular disease and neurocognitive decline, which are currently main challenges in treated patients. Lipid signaling plays a central role in modulating monocyte/macrophage activation, immune functions and inflammatory responses. Phospholipase-mediated phospholipid hydrolysis leads to the production of lipid mediators or second messengers that affect signal transduction, thus regulating a variety of physiologic and pathophysiologic processes. In this review, we discuss the contribution of phospholipases to monocyte/macrophage activation in the context of HIV-1 infection, focusing on their involvement in virus-associated chronic inflammation and co-morbidities.

Microbiota-dependent metabolite and cardiovascular disease marker trimethylamine-N-oxide (TMAO) is associated with monocyte activation but not platelet function in untreated HIV infection

Background

HIV infection is associated with increased risk of cardiovascular disease beyond that explained by traditional risk factors. Altered gut microbiota, microbial translocation, and immune activation have been proposed as potential triggers. The microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) predicts myocardial infarction (MI) in the general population and has recently been shown to induce platelet hyperreactivity. In the present study, we investigated if TMAO was associated with platelet function, microbial translocation, and immune activation in both untreated and combination anti-retroviral therapy (cART) HIV infection.

Methods

TMAO and the pre-cursors betaine, choline, and carnitine were quantified by mass-spectrometry in plasma samples from a previously established cross-sectional cohort of 50 untreated and 50 cART treated HIV-infected individuals. Whole-blood impedance aggregometry, C-reactive protein, sCD14, and lipopolysaccharide were assessed as measures of platelet function, inflammation, monocyte activation, and microbial translocation, respectively.

Results

TMAO was not associated with platelet aggregation response after stimulation with four different agonists, or with overall hypo- or hyperreactivity in untreated or treated HIV-infected individuals. In contrast, sCD14 a marker of both monocyte activation and microbial translocation was independently associated with TMAO in untreated HIV-infection (R = 0.381, P = 0.008). Lower levels of carnitine [32.2 (28.4–36.8) vs. 38.2 (33.6–42.0), P = 0.001] and betaine [33.1 (27.3–43.4) vs.37.4 (31.5–48.7, P = 0.02], but similar TMAO levels [3.8 (2.3–6.1), vs. 2.9 μM (1.9–4.8) P = 0.15] were found in cART treated compared to untreated HIV-infected individuals, resulting in higher ratios of TMAO/carnitine [0.12 (0.07–0.20) vs. 0.08 (0.05–0.11), P = 0.02] and TMAO/betaine [0.11 (0.07–0.17) vs. 0.08 (0.05–0.13), P 0.02].

Conclusions

In contrast to recent studies in HIV-uninfected populations, the present study found no evidence of TMAO-induced platelet hyperreactivity in HIV infected individuals. Microbial translocation and monocyte activation may affect TMAO levels in untreated individuals. Furthermore, the elevated ratios of TMAO/betaine and TMAO/carnitine in cART-treated individuals could possibly suggest a role of cART in TMAO metabolism.

Contribution of Oxidative Stress to Non-AIDS Events in HIV-Infected Patients

OBJECTIVE

Recognition of potentially modifiable mechanisms implicated in the pathogenesis of non-AIDS events (NAEs) might help improve outcomes of HIV-infected individuals. HIV infection has been associated with increased oxidative stress. We assessed the association between F2-isoprostanes and serious NAEs, and whether they improve the predictive performance of inflammation and coagulation biomarkers.

METHODS

Prospective multicenter cohort. Individuals who had an incident serious NAE and 2 sex- and age-matched participants with no events were selected. Measurement of F2-isoprostanes, highly sensitive C-reactive protein, interleukin-6, D-dimer, sCD14, sCD40, sCD163, and neopterin levels was performed in successive plasma samples collected from cohort inclusion.

RESULTS

Biomarkers were measured in 78 participants developing serious NAEs or death, and 151 subjects with no events. Adjusted levels of F2-isoprostanes, and also of highly sensitive C-reactive protein, sCD14, and D-dimer were higher in individuals who developed serious NAEs, including or not non-AIDS deaths. The same results were observed when only samples collected since the time of achieving virological suppression were analyzed. The additive incorporation of each biomarker, ending with F2-isoprostanes, in an adjusted model was associated with a graded and significant increase in the quality of model fitting, and 94% sensitivity, 33% specificity, and 0.77 accuracy to predict serious NAEs including non-AIDS-related death.

CONCLUSION

Oxidative stress is associated with a higher risk of serious NAEs, including non-AIDS deaths. This effect is independent and additive to biomarkers of inflammation, monocyte activation, and coagulation. Our results suggest that oxidative stress should be included among mechanisms to deal with to improve prognosis of HIV-infected individuals.

Wellens syndrome in HIV-infected patients: Two case reports

BACKGROUND

Wellens syndrome is a pattern of electrocardiographic (ECG) changes in the context of unstable angina characterized with deep inverted T-waves or biphasic T-waves in the precordial leads. These specific ECG changes are highly suggestive of stenosis in the left anterior descending artery (LAD), which can result in acute myocardial infarction, left ventricular dysfunction, or death. Human immunodeficiency virus (HIV) infection is known as an independent risk factor for the cardiovascular disease.

CASE REPORT

The first case is a 61-year-old African American female with a history of HIV infection who presented with chest pain for 8 h. Electrocardiogram (ECG) showed deep T-waves inversions in leads V3-V6. Emergent cardiac catheterization showed 99% stenosis in the mid-LAD and a drug-eluting stent (DES) was subsequently placed. The second case is a 49-year-old African American female with a medical history of type 2 diabetes mellitus, HIV, active cigarettes smoker admitted for intermittent substernal chest pain of 1-day duration. ECG showed biphasic T-wave in V2 and deep T-waves inversion in V3-V4, coronary angiography showed 95% stenosis in the proximal LAD and a DES was placed.

CONCLUSION

Wellens syndrome has characteristic ECG changes that indicates LAD stenosis. Early recognition of this syndrome, especially in HIV-infected patients who are high risk for cardiovascular disease, will help to avoid impending myocardial infarction.

HIV Persistence in Gut-Associated Lymphoid Tissues: Pharmacological Challenges and Opportunities

An increasing amount of evidence suggests that HIV replication persists in gut-associated lymphoid tissues (GALT), despite treatment with combination antiretroviral therapy (cART). Residual replication in this compartment may propagate infection at other sites in the body and contribute to sustained immune dysregulation and delayed immune recovery. Therefore, it is important to focus efforts on eliminating residual replication at this site. There are several challenges to accomplishing this goal, including low antiretroviral (ARV) exposure at specific tissue locations within GALT, which might be overcome by using the tools of clinical pharmacology. Here, we summarize the evidence for GALT as a site of residual HIV replication, highlight the consequences of persistent infection in tissues, identify current pharmacologic knowledge of drug exposure in GALT, define the challenges that hinder eradication from this site, and propose several avenues for pharmacologic intervention.

Sex-Related Differences in Inflammatory and Immune Activation Markers Before and After Combined Antiretroviral Therapy Initiation

BACKGROUND

Women progress to death at the same rate as men despite lower plasma HIV RNA (viral load). We investigated sex-specific differences in immune activation and inflammation as a potential explanation.

METHODS

Inflammatory and immune activation markers [interferon γ, tumor necrosis factor (TNF) α, IL-6, IL-18, IFN-γ-induced protein 10, C-reactive protein (CRP), lipopolysaccharide, and sCD14] were measured at weeks 0, 24, and 48 after combination antiretroviral therapy (cART) in a random subcohort (n = 215) who achieved virologic suppression in ACTG A5175 (Prospective Evaluation of Antiretrovirals in Resource-Limited Settings). Association between sex and changes in markers post-cART was examined using random effects models. Average marker differences and 95% confidence intervals were estimated using multivariable models.

RESULTS

At baseline, women had lower median log10 viral load (4.93 vs 5.18 copies per milliliter, P = 0.01), CRP (2.32 vs 4.62 mg/L, P = 0.01), detectable lipopolysaccharide (39% vs 55%, P = 0.04), and sCD14 (1.9 vs 2.3 µg/mL, P = 0.06) vs men. By week 48, women had higher interferon γ (22.4 vs 14.9 pg/mL, P = 0.05), TNF-α (11.5 vs 9.5 pg/mL, P = 0.02), and CD4 (373 vs 323 cells per cubic millimeter, P = 0.02). In multivariate analysis, women had greater increases in CD4 and TNF-α but less of a decrease in CRP and sCD14 compared with men.

CONCLUSIONS

With cART-induced viral suppression, women have less reduction in key markers of inflammation and immune activation compared with men. Future studies should investigate the impact of these sex-specific differences on morbidity and mortality.

Porphyromonas gingivalis antibody levels and diagnosis of coronary artery disease in HIV-positive individuals

BACKGROUND AND OBJECTIVE

Periodontal disease has been associated with cardiovascular disease in the general population. It is unknown whether IgG antibody levels for periodontal pathogens are associated with the diagnosis of coronary artery disease (CAD) in HIV-positive individuals.

MATERIAL AND METHODS

Twenty-four HIV-positive individuals (cases) with stored plasma available in the 12 months before CAD diagnosis were age- and sex-matched 1:2 with 46 HIV-positive individuals without CAD (controls). Antibody levels to whole cell extracts from periodontal pathogens Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum, as well as markers of inflammation sCD14, CXCL10 and high-sensitivity C-reactive protein, were compared between cases and controls using enzyme-linked immunosorbent assays.

RESULTS

P. gingivalis-specific IgG levels (μg/mL) were significantly higher in individuals with CAD (median 1.48 [IQR 1.06-2.05]) compared to controls (0.70 [IQR 0.35-1.24], P<.001), and remained significantly higher following adjustment for traditional cardiovascular risk factors and HIV viral load (OR 21.6 [95% CI 3.73-125.63] P=.001). There was a borderline association between A. actinomycetemcomitans IgG antibody levels (cases, median 3.86 [IQR 3.19-4.72]; controls, 3.34 [IQR 2.59-4.07], P=.050) and no association found between F. nucleatum antibody levels and CAD. sCD14 levels (μg/mL) were higher in cases compared with controls (median 3.45 [IQR 3.03-4.11] vs 2.65 [IQR 2.32-2.99] P<.001), while CXCL10 (median 127 pg/mL [IQR 88-157] vs 153 [IQR 90-244] P=.321) and high-sensitivity C-reactive protein (median 3.44 mg/L [1.98-5.32] vs 1.85 [1.13-6.88] P=.203) levels were not different between cases and controls.

CONCLUSION

Periodontal bacteria may be contributing to CAD risk in HIV-positive individuals.

Soluble Levels of Receptor for Advanced Glycation Endproducts (RAGE) and Progression of Atherosclerosis in Individuals Infected with Human Immunodeficiency Virus: ACTG NWCS 332

Identification of biomarkers and/or mediators of cardiovascular disease (CVD) associated with HIV infection would be of diagnostic and therapeutic value. As soluble receptor for advanced glycation endproducts (sRAGE) and endogenous secretory (esRAGE) have been implicated in vascular complications in other settings, we investigated whether either soluble form of RAGE was associated with changes in carotid intima-media thickness (CIMT) in HIV-infected patients and HIV-uninfected controls. We found no differences in sRAGE, esRAGE, or CIMT among groups at study entry, or in yearly rates of change in sRAGE, esRAGE, or CIMT by HIV-serostatus (all p > 0.10). However, yearly rates of change in sRAGE (p = 0.07) and esRAGE (p < 0.001) were higher in those taking protease inhibitors, and lower baseline esRAGE levels (p = 0.06) were associated with increased odds of CIMT progression in HIV-infected individuals. Although esRAGE was not altered by HIV-serostatus (p = 0.17), its inverse relationship with CIMT progression in HIV-infected patients suggests a possible role as a mediator of CVD in HIV-infected persons.

The Expression Level of Neutrophil CD64 Is a Useful Marker of Systemic Inflammation Associated with HIV Infection

CD64 is an Fc-gamma-receptor type 1. The expression level of neutrophil CD64 (nCD64) is a known bacterial infection marker, and it also increases in viral infections. We examined the absolute nCD64 before and after the initiation of antiretroviral therapy (ART) to determine its role as an infection and inflammation marker of human immunodeficiency virus (HIV) infection. In this prospective observational study, 94 HIV-infected patients were enrolled and classified into ART (n = 62), ART naive (n = 24), and acute/early phase groups (n = 8). The median nCD64 was 1,430 molecules/cell in the ART group, 2,994 in the ART naive group, 4,625 in the acute/early phase group, and 1,196 in the healthy control group. The nCD64 in the ART group was significantly higher compared with the healthy controls (p = .041), and the nCD64 in the ART naive and acute/early phase groups was significantly higher compared with the ART group (both p < .001). In the ART naive group, nCD64 was significantly higher in patients with than without concomitant infections (3,942 ± 1,519 vs. 2,300 ± 784, p = .004). However, this was influenced by the fact that nCD64 elevated as the stage of HIV infection progressed. nCD64 decreased significantly during the 24 weeks after starting ART (p = .004), although an upward trend in nCD64 was observed at weeks 2 and 4, without symptoms. When immune reconstitution inflammatory syndrome occurred, nCD64 elevated with a wider range than did C-reactive protein. This preliminary study suggests that nCD64 would be useful as a marker of the systemic inflammation of HIV-infected patients.

Impact of probiotic Saccharomyces boulardii on the gut microbiome composition in HIV-treated patients: A double-blind, randomised, placebo-controlled trial

Dysbalance in gut microbiota has been linked to increased microbial translocation, leading to chronic inflammation in HIV-patients, even under effective HAART. Moreover, microbial translocation is associated with insufficient reconstitution of CD4+T cells, and contributes to the pathogenesis of immunologic non-response. In a double-blind, randomised, placebo-controlled trial, we recently showed that, compared to placebo, 12 weeks treatment with probiotic Saccharomyces boulardii significantly reduced plasma levels of bacterial translocation (Lipopolysaccharide-binding protein or LBP) and systemic inflammation (IL-6) in 44 HIV virologically suppressed patients, half of whom (n = 22) had immunologic non-response to antiretroviral therapy (<270 CD4+Tcells/μL despite long-term suppressed viral load). The aim of the present study was to investigate if this beneficial effect of the probiotic Saccharomyces boulardii is due to modified gut microbiome composition, with a decrease of some species associated with higher systemic levels of microbial translocation and inflammation. In this study, we used 16S rDNA gene amplification and parallel sequencing to analyze the probiotic impact on the composition of the gut microbiome (faecal samples) in these 44 patients randomized to receive oral supplementation with probiotic or placebo for 12 weeks. Compared to the placebo group, in individuals treated with probiotic we observed lower concentrations of some gut species, such as those of the Clostridiaceae family, which were correlated with systemic levels of bacterial translocation and inflammation markers. In a sub-study of these patients, we observed significantly higher parameters of microbial translocation (LBP, soluble CD14) and systemic inflammation in immunologic non-responders than in immunologic responders, which was correlated with a relative abundance of specific gut bacterial groups (Lachnospiraceae genus and Proteobacteria). Thus, in this work, we propose a new therapeutic strategy using the probiotic yeast S. boulardii to modify gut microbiome composition. Identifying pro-inflammatory species in the gut microbiome could also be a useful new marker of poor immune response and a new therapeutic target.

Immune activation and cardiovascular disease in chronic HIV infection

PURPOSE OF REVIEW

This article describes the potential contribution of immune activation in the pathogenesis of HIV-associated cardiovascular disease (CVD) - a leading cause of morbidity and mortality among HIV-positive persons with access to antiretroviral therapy (ART).

RECENT FINDINGS

We review recent literature that suggests abnormalities in both adaptive and innate immunity contributes to CVD risk among persons with HIV infection. In particular, potentially atherogenic T-cell mechanisms include persistent high-level T-cell activation (and associated proinflammatory mechanisms), as well as the presence of copathogens (e.g., cytomegalovirus) providing an ongoing stimulus for cytotoxic T-cell responses. More recent data have then emphasized the potential impact of monocyte-/macrophage-mediated inflammation and injury within atherosclerotic lesions. The abnormality driving innate immune activation many not fully reverse with antiretroviral therapy, highlighting the need for interventions that target inflammation as a CVD prevention strategy.

SUMMARY

Premature CVD among persons with HIV infection is due, in part, to persistent abnormalities in immune activation and systemic inflammation despite viral suppression. Prevention strategies for persons with HIV infection include those that target traditional CVD risk factors, as well as newer candidate treatments with potential immunomodulatory benefits.

(1→3)-β-d-Glucan: A Biomarker for Microbial Translocation in Individuals with Acute or Early HIV Infection?

Background

The extent of gut microbial translocation, which plays roles in HIV disease progression and non-AIDS comorbidities, appears to vary with the composition of the gut microbiome, particularly the presence of Lactobacillales, which reduce mucosal injury. While low proportions of Lactobacillales in the distal gut microbiome are a very promising indicator of microbial translocation, measurement is expensive and complicated and not feasible for clinical routine. (1→3)-β-d-Glucan (BDG) is a component of most fungal cell walls and might be a surrogate marker for Lactobacillales proportion in the gut and a useful indicator of HIV-associated gut injury. This study evaluated BDG as a biomarker of gut integrity in adults with acute or early HIV infection (AEH).

Methods

Study samples were collected longitudinally during study visits at weeks 0, 12, and 24 in a cohort of 11 HIV-infected men starting antiretroviral therapy during AEH. Blood plasma levels of BDG, soluble cluster of differentiation 14 (sCD14) and lipopolysaccharide (LPS) were measured and then correlated with the proportion of Lactobacillales in the distal gut microbiome, as measured by 16s rDNA sequencing by using mixed-effects models with random intercepts.

Results

Mean BDG and sCD14 levels across subjects were associated with Lactobacillales after controlling for time effects and within-subjects correlations (p-values < 0.05), while LPS levels were not. Specifically, each point increase in mean BDG and sCD14 levels across participants was associated with 0.31 ± 0.14 and 0.03 ± 0.01 percent decrease in mean Lactobacillales proportions, respectively.

Conclusion

BDG and sCD14 may be indicators of low Lactobacillales in the gut in adults with acute or early HIV infection, and serve as biomarkers of gut integrity and microbial translocation in HIV infection. Larger studies are needed to confirm our findings.

Changes in plasma levels of oxidized lipoproteins and lipoprotein subfractions with atazanavir-, raltegravir-, darunavir-based initial antiviral therapy and associations with common carotid artery intima-media thickness: ACTG 5260s

BACKGROUND

The role of oxidized lipoproteins (high-density [HDLox] and low-density [LDLox]) and total lipoprotein particle (Lp) number and size in HIV-related cardiovascular disease (CVD) is unclear. The goal of this study was to evaluate changes of these biomarkers and their associations with rate of carotid intima media thickness progression over 3 years (ΔCIMT) in chronic HIV infection.

METHODS

Prospective study of 234 HIV-infected antiretroviral treatment-naive participants without CVD who were randomized to receive tenofovir-emtricitabine plus atazanavir/ritonavir, darunavir/ritonavir or raltegravir (RAL) and achieved plasma HIV-1 RNA <50 copies/ml by week 24 and thereafter. Biomarker changes over 24, 48 or 96 weeks from baseline and pairwise treatment group comparisons were examined. Associations of these biomarkers with ΔCIMT were analysed with mixed effects linear regression.

RESULTS

HDLp number increased with both protease inhibitors (PIs) over 48 weeks, while LDLp number declined with RAL; Lp size did not change. Over 96 weeks, normalized HDLox declined with both PIs; LDLox increased in all groups. Few treatment group differences were observed across all biomarkers. Associations between ΔCIMT and oxidized lipoproteins at all time points were not apparent (P≥0.10). There was some evidence of slower ΔCIMT for higher HDLp number (P=0.06) and for lower LDLp number (P=0.08) measured at baseline.

CONCLUSIONS

Unexpectedly, LDLox increased modestly in all treatment groups after ART initiation. Associations of plasma HDLox and LDLox with ΔCIMT were not apparent. While plasma levels of abnormal lipoproteins have been shown to be associated with CVD outcomes, clear associations with sub-clinical atherosclerosis progression were not apparent in our study.

Plasma IL-6 levels are independently associated with atherosclerosis and mortality in HIV-infected individuals on suppressive antiretroviral therapy

OBJECTIVE

To determine the associations of markers of immune activation with atherosclerosis and mortality, in participants with treated and suppressed HIV infection.

DESIGN

Observational study of 149 HIV-infected participants with virologic suppression on antiretroviral therapy.

METHODS

Cryopreserved mononuclear cells and plasma were used to evaluate markers of T cell and monocyte activation, inflammation and coagulopathy. Carotid artery intima-media thickness (CIMT) was measured by high-resolution ultrasound at the common, bifurcation and internal carotid regions. Associations of immunologic markers with CIMT and all-cause mortality were assessed using multivariable linear regression and Cox proportional hazards regression.

RESULTS

The majority of participants were men (93%) and white (67%), median age of 48.5 years and median CD4 T-cell count of 522 cells/μl. The median baseline IMT was 1.0 mm. Over a median of 8.3-year follow-up, 12 deaths occurred. In multivariate analysis, adjusted for traditional cardiovascular risk factors, higher monocyte C-C motif chemokine receptor 5 (CCR5) expression [5.4%, P = 0.001] was associated with greater common CIMT. Higher plasma IL-6 was associated with greater bifurcation [8.0%, P = 0.007] and overall mean IMT [5.2%, P = 0.026]. Finally, higher plasma IL-6 [hazard ratio 1.9, P = 0.030], internal carotid [hazard ratio 4.1, P = 0.022] and mean IMT [hazard ratio 5.2, P = 0.026] were individually associated with all-cause mortality.

CONCLUSION

Higher monocyte CCR5 expression and plasma IL-6 were associated with atherosclerosis, independent of traditional cardiovascular risk factors. IL-6 and CIMT were individually associated with all-cause mortality. The impact of therapies targeting immune activation in cardiovascular disease in treated HIV infection merits additional investigation.

Risk of Cardiovascular Disease in an Aging HIV Population: Where Are We Now?

With more effective and widespread antiretroviral treatment, the overall incidence of AIDS- or HIV-related death has decreased dramatically. Consequently, as patients are aging, cardiovascular disease (CVD) has emerged as an important cause of morbidity and mortality in the HIV population. The incidence of CVD overall in HIV is relatively low, but it is approximately 1.5-2-fold higher than that seen in age-matched HIV-uninfected individuals. Multiple factors are believed to explain this excess in risk such as overrepresentation of traditional cardiovascular risk factors (particularly smoking), toxicities associated with cumulative exposure to some antiretroviral agents, together with persistent chronic inflammation, and immune activation associated with HIV infection. Tools are available to calculate an individual's predicted risk of CVD and should be incorporated in the regular follow-up of HIV-infected patients. Targeted interventions to reduce this risk must be recommended, including life-style changes and medical interventions that might include changes in antiretroviral therapy.

Genetic polymorphisms in the CD14 gene are associated with monocyte activation and carotid intima-media thickness in HIV-infected patients on antiretroviral therapy

HIV-infected individuals on antiretroviral therapy (ART) are at increased risk of cardiovascular disease (CVD). Given the relationship between innate immune activation and CVD, we investigated the association of single-nucleotide polymorphisms (SNPs) in TLR4 and CD14 and carotid intima-media thickness (cIMT), a surrogate measurement for CVD, in HIV-infected individuals on ART and HIV-uninfected controls as a cross-sectional, case-control study. We quantified the frequency of monocyte subsets (CD14, CD16), markers of monocyte activation (CD38, HLA-DR), and endothelial adhesion (CCR2, CX3CR1, CD11b) by flow cytometry. Plasma levels of lipopolysaccharide, sCD163, sCD14, sCX3CL1, and sCCL2, were measured by ELISA. Genotyping of TLR4 and CD14 SNPs was also performed. The TT genotype for CD14/-260SNP but not the CC/CT genotype was associated with elevated plasma sCD14, and increased frequency of CD11b+CD14+ monocytes in HIV-infected individuals. The TT genotype was associated with lower cIMT in HIV-infected patients (n = 47) but not in HIV-uninfected controls (n = 37). The AG genotype for TLR4/+896 was associated with increased CX3CR1 expression on total monocytes among HIV-infected individuals and increased sCCL2 and fibrinogen levels in HIV-uninfected controls. SNPs in CD14/-260 and TLR4/+896 were significantly associated with different markers of systemic and monocyte activation and cIMT that differed between HIV-infected participants on ART and HIV-uninfected controls. Further investigation on the relationship of these SNPs with a clinical endpoint of CVD is warranted in HIV-infected patients on ART.

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.