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

Menopause and Estrogen Associations With Gut Barrier, Microbial Translocation, and Immune Activation Biomarkers in Women With and Without HIV

OBJECTIVES

Estrogens may protect the gut barrier and reduce microbial translocation and immune activation, which are prevalent in HIV infection. We investigated relationships of the menopausal transition and estrogens with gut barrier, microbial translocation, and immune activation biomarkers in women with and without HIV.

DESIGN

Longitudinal and cross-sectional studies nested in the Women's Interagency HIV Study.

METHODS

Intestinal fatty acid binding protein, lipopolysaccharide binding protein, and soluble CD14 (sCD14) levels were measured in serum from 77 women (43 with HIV) before, during, and after the menopausal transition (∼6 measures per woman over ∼13 years). A separate cross-sectional analysis was conducted among 72 postmenopausal women with HIV with these biomarkers and serum estrogens.

RESULTS

Women in the longitudinal analysis were a median age of 43 years at baseline. In piecewise, linear, mixed-effects models with cutpoints 2 years before and after the final menstrual period to delineate the menopausal transition, sCD14 levels increased over time during the menopausal transition (Beta [95% CI]: 38 [12 to 64] ng/mL/yr, P = 0.004), followed by a decrease posttransition (-46 [-75 to -18], P = 0.001), with the piecewise model providing a better fit than a linear model (P = 0.0006). In stratified analyses, these results were only apparent in women with HIV. In cross-sectional analyses, among women with HIV, free estradiol inversely correlated with sCD14 levels (r = -0.26, P = 0.03). Lipopolysaccharide binding protein and intestinal fatty acid binding protein levels did not appear related to the menopausal transition and estrogen levels.

CONCLUSIONS

Women with HIV may experience heightened innate immune activation during menopause, possibly related to the depletion of estrogens.

Gut permeability is associated with lower insulin sensitivity in youth with perinatally acquired HIV

The relationships between alterations in the intestinal barrier, and bacterial translocation with the development of metabolic complications in youth with perinatally acquired HIV (YPHIV) have not been investigated. The PHACS Adolescent Master Protocol enrolled YPHIV across 15 U.S. sites, including Puerto Rico, from 2007 to 2009. For this analysis, we included YPHIV with HIV viral load 1000 c/ml or less, with at least one measurement of homeostatic assessment of insulin resistance (HOMA-IR) or nonhigh density lipoprotein (non-HDLc) between baseline and year 3 and plasma levels of intestinal fatty-acid binding protein (I-FABP), lipopolysaccharide-binding protein (LBP), and zonulin levels at baseline. We fit linear regression models using generalized estimating equations to assess the association of baseline log 10 gut markers with log 10 HOMA-IR and non-HDLc at all timepoints. HOMA-IR or non-HDLc was measured in 237, 189, and 170 PHIV at baseline, Yr2, and Yr3, respectively. At baseline, median age (Q1, Q3) was 12 years (10, 14), CD4 + cell count was 762 cells/μl (574, 984); 90% had HIV RNA less than 400 c/ml. For every 10-fold higher baseline I-FABP, HOMA-IR dropped 0.85-fold at baseline and Yr2. For a 10-fold higher baseline zonulin, there was a 1.35-fold increase in HOMA-IR at baseline, 1.23-fold increase in HOMA-IR at Yr2, and 1.20-fold increase in HOMA-IR at Yr3 in adjusted models. For a 10-fold higher baseline LBP, there was a 1.23-fold increase in HOMA-IR at baseline in the unadjusted model, but this was slightly attenuated in the adjusted model. Zonulin was associated with non-HDLc at baseline, but not for the other time points. Despite viral suppression, intestinal damage may influence downstream insulin sensitivity in YPHIV.

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.

The changing landscape of HIV-associated kidney disease

The HIV epidemic has devastated millions of people globally, with approximately 40 million deaths since its start. The availability of antiretroviral therapy (ART) has transformed the prognosis of millions of individuals infected with HIV such that a diagnosis of HIV infection no longer automatically confers death. However, morbidity and mortality remain substantial among people living with HIV. HIV can directly infect the kidney to cause HIV-associated nephropathy (HIVAN) - a disease characterized by podocyte and tubular damage and associated with an increased risk of kidney failure. The reports of HIVAN occurring primarily in those of African ancestry led to the discovery of its association with APOL1 risk alleles. The advent of ART has led to a substantial decrease in the prevalence of HIVAN; however, reports have emerged of an increase in the prevalence of other kidney pathology, such as focal segmental glomerulosclerosis and pathological conditions associated with co-morbidities of ageing, such as hypertension and diabetes mellitus. Early initiation of ART also results in a longer cumulative exposure to medications, increasing the likelihood of nephrotoxicity. A substantial body of literature supports the use of kidney transplantation in people living with HIV, demonstrating significant survival benefits compared with that of people undergoing chronic dialysis, and similar long-term allograft and patient survival compared with that of HIV-negative kidney transplant recipients.

Efficacy and safety of raltegravir plus lamivudine maintenance therapy

BACKGROUND

Decreasing medication burden with raltegravir plus lamivudine in virologically suppressed persons with HIV (PWH) maintained efficacy and was well tolerated at 24 weeks, but more comprehensive data over longer follow-up are required.

METHODS

Prospective 48 week extension phase of the raltegravir plus lamivudine arm from a previous 24 week pilot randomized clinical trial in which virologically suppressed PWH were randomized 2:1 to switch to fixed-dose combination 150 mg lamivudine/300 mg raltegravir twice daily or to continue therapy. In this 48 week extension phase, raltegravir was dosed at 1200 mg/day and lamivudine 300 mg/day. Primary outcome was the proportion of PWH with treatment failure at Week 48. Secondary outcomes were changes in ultrasensitive plasma HIV RNA, HIV DNA in CD4 cells, serum IL-6, ultrasensitive C-reactive protein and sCD14, body composition, sleep quality, quality of life and adverse effects.

RESULTS

Between May 2018 and June 2019, 33 PWH were enrolled. One participant experienced virological failure without resistance mutations and re-achieved sustained virological suppression without therapy discontinuation, and two others discontinued therapy due to adverse effects. Treatment failure was 9% (95% CI 2%-24%) and 3% (95% CI 0%-17%) in the ITT and on-treatment populations. There were significant changes between baseline and Week 48 in serum cytokines but not in other secondary outcomes.

CONCLUSIONS

Switching to raltegravir and lamivudine in PWH with virological suppression maintains efficacy and is well tolerated. This maintenance regimen might be a cost-effective option for PWH at risk of drug-drug interactions or needing to avoid specific toxicities of certain antiretroviral drugs or their negative impact on comorbidities.

Pitavastatin in the Prevention of Cardiovascular Disease in People Living with HIV: A Review

HIV is associated with a wide array of pathophysiologic mechanisms that ultimately contribute to mortality. While HIV is traditionally known as a disease that attacks the immune system, it is now established that infection with HIV can cause cardiovascular disease (CVD). Through inflammation, atherogenesis, interactions with antiretroviral therapy/highly-active antiretroviral therapy (ART/HAART), and other mechanisms, HIV is an independent risk factor for the development of CVD. The treatment of the CVD risks associated with HIV is complicated, especially due to interactions with hyperlipidemic drugs and ART/HAART. There is a prompt need for a drug (or drug class) that is known to reduce the risk of CVD, specifically in people living with HIV. Recently, the randomized trial to prevent vascular events in HIV trial evaluated the usage of pitavastatin in preventing major cardiac events in people with HIV, showing a significant reduction in cardiac events among those taking the therapeutic. In this review, we evaluate the mechanisms by which HIV contributes to CVD, and the randomized trial to prevent vascular events in HIV trial, and postulate about future directions of the drug in treating people living with HIV.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

HIV-1-Host Interaction in Gut-Associated Lymphoid Tissue (GALT): Effects on Local Environment and Comorbidities

HIV-1 replication in the gastrointestinal (GI) tract causes severe CD4+ T-cell depletion and disruption of the protective epithelial barrier in the intestinal mucosa, causing microbial translocation, the main driver of inflammation and immune activation, even in people living with HIV (PLWH) taking antiretroviral drug therapy. The higher levels of HIV DNA in the gut compared to the blood highlight the importance of the gut as a viral reservoir. CD4+ T-cell subsets in the gut differ in phenotypic characteristics and differentiation status from the ones in other tissues or in peripheral blood, and little is still known about the mechanisms by which the persistence of HIV is maintained at this anatomical site. This review aims to describe the interaction with key subsets of CD4+ T cells in the intestinal mucosa targeted by HIV-1 and the role of gut microbiome and its metabolites in HIV-associated systemic inflammation and immune activation that are crucial in the pathogenesis of HIV infection and related comorbidities.

Monocyte-derived Dll4 is a novel contributor to persistent systemic inflammation in HIV patients

Background

In people living with HIV (PLWH) on combination antiretroviral therapy (cART), persistent systemic inflammation is a driving force for the progression of comorbidities, such as cardiovascular and cerebrovascular diseases. In this context, monocyte- and macrophage-related inflammation rather than T cell activation is a major cause of chronic inflammation. However, the underlying mechanism of how monocytes cause persistent systemic inflammation in PLWH is elusive.

Methods and Results

In vitro, we demonstrated that lipopolysaccharides (LPS) or tumor necrosis factor alpha (TNFα), induced a robust increase of Delta-like ligand 4 (Dll4) mRNA and protein expression in human monocytes and Dll4 secretion (extracellular Dll4, exDll4) from monocytes. Enhanced membrane-bound Dll4 (mDll4) expression in monocytes triggered Notch1 activation to promote pro-inflammatory factors expression. Dll4 silencing and inhibition of Nocth1 activation diminished the LPS or TNFα -induced inflammation. exDll4 releases in response to cytokines occurred in monocytes but not endothelial cells or T cells. In clinical specimens, we found that PLWH, both male and female, on cART, showed a significant increase in mDll4 expression, activation of Dll4-Notch1 signaling, and inflammatory markers in monocytes. Although there was no sex effect on mDII4 in PLWH, plasma exDll4 was significantly elevated in males but not females compared to HIV uninfected individuals. Furthermore, exDll4 plasma levels paralleled with monocytes mDll4 in male PLWH. Circulating exDll4 was also positively associated with pro-inflammatory monocytes phenotype and negatively associated with classic monocytes phenotype in male PLWH.

Conclusion

Pro-inflammatory stimuli increase Dll4 expression and Dll4-Notch1 signaling activation in monocytes and enhance monocyte proinflammatory phenotype, contributing to persistent systemic inflammation in male and female PLWH. Therefore, monocyte mDll4 could be a potential biomarker and therapeutic target of systemic inflammation. Plasma exDll4 may also play an additional role in systemic inflammation but primarily in men.

Human Immunodeficiency Virus and Clonal Hematopoiesis

The evolution of antiretroviral therapies (ART) has tremendously improved the life expectancy of people living with human immunodeficiency virus (HIV) (PLWH), which is currently similar to the general population. However, as PLWH are now living longer, they exhibit various comorbidities such as a higher risk of cardiovascular disease (CVD) and non-acquired immunodeficiency syndrome (AIDS)-defined malignancies. Clonal hematopoiesis (CH) is the acquisition of somatic mutations by the hematopoietic stem cells, rendering them survival and growth benefit, thus leading to their clonal dominance in the bone marrow. Recent epidemiologic studies have highlighted that PLWH have a higher prevalence of CH, which in turn is associated with increased CVD risk. Thus, a link between HIV infection and a higher risk for CVD might be explained through the induction of inflammatory signaling in the monocytes carrying CH mutations. Among the PLWH, CH is associated with an overall poorer control of HIV infection; an association that requires further mechanistic evaluation. Finally, CH is linked to an increased risk of progression to myeloid neoplasms including myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), which are associated with particularly poor outcomes among patients with HIV infection. These bidirectional associations require further molecular-level understanding, highlighting the need for more preclinical and prospective clinical studies. This review summarizes the current literature on the association between CH and HIV infection.

Heroin Use Is Associated With Vascular Inflammation in Human Immunodeficiency Virus

BACKGROUND

Heroin use may work synergistically with human immunodeficiency virus (HIV) infection to cause greater immune dysregulation than either factor alone. Unraveling how this affects end-organ disease is key as it may play a role in the excess mortality seen in people with HIV (PWH) who use heroin despite access to care and antiretroviral therapy.

METHODS

This is a prospectively enrolled, cross-sectional study of adults with and without HIV who use and do not use heroin using (18)F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to compare tissue-specific inflammation including aortic (target-to-background ratio [TBR]), splenic, and bone marrow (standardized uptake value [SUV]).

RESULTS

A total of 120 participants were enrolled. The unadjusted mean difference in aortic TBR was 0.43 between HIV-positive [HIV+] heroin+ and HIV+ heroin-negative [heroin-] (P = .02); however, among HIV-, aortic TBR was similar regardless of heroin-use status. Further, HIV-by-heroin-use status interaction was significant (P = .02), indicating that the relationship between heroin use and higher aortic TBR depended on HIV status. On the other hand, both HIV (1.54 vs 1.68; P = .04, unadjusted estimated means for HIV+ vs HIV-) and heroin use were associated with lower bone marrow SUV, although the effect of heroin depended on sex (heroin-use-by-sex interaction, P = .03). HIV-by-heroin-use interaction was not significant for splenic or bone marrow SUV.

CONCLUSIONS

Aortic inflammation was greatest in PWH who use heroin, but paradoxically, bone marrow activity was the least in this group, suggesting complex and possibly divergent pathophysiology within these different end organs.

The Gut Microbiome, Microbial Metabolites, and Cardiovascular Disease in People Living with HIV

PURPOSE OF REVIEW

To synthesize recent evidence relating the gut microbiome and microbial metabolites to cardiovascular disease (CVD) in people living with HIV (PLWH).

RECENT FINDINGS

A few cross-sectional studies have reported on the gut microbiome and cardiovascular outcomes in the context of HIV, with no consistent patterns emerging. The largest such study found that gut Fusobacterium was associated with carotid artery plaque. More studies have evaluated microbial metabolite trimethylamine N-oxide with CVD risk in PLWH, but results were inconsistent, with recent prospective analyses showing null effects. Studies of other microbial metabolites are scarce. Microbial translocation biomarkers (e.g., lipopolysaccharide binding protein) have been related to incident CVD in PLWH. Microbial translocation may increase CVD risk in PLWH, but there is insufficient and/or inconsistent evidence regarding specific microbial species and microbial metabolites associated with cardiovascular outcomes in PLWH. Further research is needed in large prospective studies integrating the gut microbiome, microbial translocation, and microbial metabolites with cardiovascular outcomes in PLWH.

Macrophage-Targeted Sodium Chlorite (NP001) Slows Progression of Amyotrophic Lateral Sclerosis (ALS) through Regulation of Microbial Translocation

Amyotrophic lateral sclerosis (ALS) is a heterogeneous, progressive, and universally fatal neurodegenerative disease. A subset of ALS patients has measurable plasma levels of lipopolysaccharide (LPS) and C-reactive protein (CRP) consistent with low-grade microbial translocation (MT). Unless interrupted, MT sets up a self-perpetuating loop of inflammation associated with systemic macrophage activation. To test whether MT contributed to ALS progression, blood specimens from a phase 2 study of NP001 in ALS patients were evaluated for changes in activity in treated patients as compared to controls over the 6-month study. In this post hoc analysis, plasma specimens from baseline and six-month timepoints were analyzed. Compared with baseline values, biomarkers related to MT were significantly decreased (LPS, LPS binding protein (LBP), IL-18, Hepatocyte growth factor (HGF), soluble CD163 (sCD163)) in NP001-treated patients as compared to controls, whereas wound healing and immunoregulatory factors were increased (IL-10, Epidermal growth factor (EGF), neopterin) by the end of study. These biomarker results linked to the positive clinical trial outcome confirm that regulation of macrophage activation may be an effective approach for the treatment of ALS and, potentially, other neuroinflammatory diseases related to MT.

Comprehensive assessment of neurocognitive function, inflammation markers, and adiposity in treated HIV and control

To compare the neurocognitive scores between persons living with human immunodeficiency virus (PLWH) and persons without human immunodeficiency virus (HIV) and assess the relationship between neurocognition, HIV status and variables, inflammation, and body composition measures. Cross-sectional study involving 225 participants (126 PLWH on antiretroviral therapy [ART] and 99 persons without HIV). For the first time in HIV, we used Cognivue®, an food and drug administration (FDA)-approved computer-based test to assess cognitive function. The test was calibrated to individuals' unique cognitive ability and measured 6 cognitive domains and 2 performance parameters. Markers of inflammation, immune activation, insulin resistance, and body fat composition (using dual-energy X-ray absorptiometry scan) were collected. Classical t tests, chi-square tests, and spearman correlations were used to compare and explore relationships between variables. Inverse probability weighting adjusted average treatment effect models were performed to evaluate the differences between PLWH and persons without HIV, adjusting for age, race, sex, and heroin use. Overall, 64% were male, 46% were Black, with a mean age of 43 years. Among PLWH, 83% had an undetectable HIV-1 RNA level (≤20 copies/mL). Compared persons without HIV, PLWH performed poorer across 4 domains: visuospatial (P = .035), executive function (P = .029), naming/language (P = .027), and abstraction (P = .018). In addition, PLWH had a significantly longer processing speed time compared to controls (1686.0 ms vs 1606.0 ms [P = .007]). In PLWH, lower cognitive testing domain scores were associated with higher inflammatory markers (high sensitivity C-reactive protein [hsCRP]) and with higher total fat and visceral adipose tissue (P < .05). Neurocognitive impairment (NCI) in HIV is associated with inflammation and total and central adiposity.

Factors Associated With Systemic Immune Activation Indices in a Global Primary Cardiovascular Disease Prevention Cohort of People With Human Immunodeficiency Virus on Antiretroviral Therapy

BACKGROUND

Among antiretroviral therapy (ART)-treated people with human immunodeficiency virus (PWH), persistent systemic immune activation contributes to atherogenesis atherosclerotic, cardiovascular disease (CVD) events, and mortality. Factors associated with key immune activation indices have not previously been characterized among a global primary CVD prevention cohort of PWH.

METHODS

Leveraging baseline Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) data, we evaluated factors associated with soluble CD14 (sCD14) and oxidized low-density lipoprotein (oxLDL).

RESULTS

The primary analysis cohort included 4907 participants from 5 global-burden-of-disease regions (38% female, 48% Black, median age 50 years). In fully adjusted models for sCD14, female sex and White race (among those in high-income regions) were associated with higher sCD14 levels, while higher body mass index (BMI) and current use of nucleoside reverse transcriptase inhibitor + integrase strand transfer inhibitor ART were associated with lower sCD14 levels. In fully adjusted models for oxLDL, male sex, residence in high-income regions, White race (among those in high-income regions), and higher BMI were associated with higher oxLDL levels. In a subanalysis cohort of 1396 women with HIV, increased reproductive age was associated with higher sCD14 levels but not with higher oxLDL levels.

CONCLUSIONS

Factors associated with sCD14 and oxLDL, 2 key indices of immune-mediated CVD risk, differ. Future studies will elucidate ways in which medications (eg, statins) and behavioral modifications influence sCD14 and oxLDL and the extent to which dampening of these markers mediates CVD-protective effects.

CLINICAL TRIALS REGISTRATION

NCT0234429.

Clonal hematopoiesis in men living with HIV and association with subclinical atherosclerosis

OBJECTIVES

People with HIV (PWH) are at increased risk for premature cardiovascular disease (CVD). Clonal hematopoiesis is a common age-related condition that may be associated with increased CVD risk. The goal of this study was to determine the prevalence of clonal hematopoiesis and its association with chronic inflammation and CVD in PWH.

DESIGN

Cross-sectional study utilizing archived specimens and data from 118 men (86 PWH and 32 HIV-uninfected) from the Baltimore-Washington DC center of the Multicenter AIDS Cohort Study (MACS) who had had coronary computed tomography angiography (CTA) and measurement of 34 serologic inflammatory biomarkers.

METHODS

Clonal hematopoiesis was assessed on peripheral blood mononuclear cells utilizing targeted error-corrected next generation sequencing (NGS) focused on 92 genes frequently mutated in hematologic malignancies. Clinical and laboratory data were obtained from the MACS database.

RESULTS

Clonal hematopoiesis with a variant allele frequency (VAF) greater than 1% was significantly more common in PWH [20/86 (23.3%)] than in HIV-uninfected men [2/32 (6.3%)] ( P  = 0.035). PWH with clonal hematopoiesis (VAF > 1%) were more likely to have coronary artery stenosis of at least 50% than those without clonal hematopoiesis [6/20 (30%) vs. 6/64 (9%); P  = 0.021]. Presence of clonal hematopoiesis was not significantly associated with serological inflammatory markers, except for significantly lower serum leptin levels; this was not significant after adjustment for abdominal or thigh subcutaneous fat area.

CONCLUSION

Clonal hematopoiesis was more common in PWH and among PWH was associated with the extent of coronary artery disease. Larger studies are needed to further examine the biological and clinical consequences of clonal hematopoiesis in PWH.

Estrogen May Enhance Toll-Like Receptor 4-Induced Inflammatory Pathways in People With HIV: Implications for Transgender Women on Hormone Therapy

Background

Transgender women (TW) are at increased risk for both human immunodeficiency virus (HIV) and cardiovascular disease (CVD). Antiretroviral therapy-treated HIV has been associated with a two-fold increased risk of CVD, potentially due to dysregulated Toll-like receptor (TLR)-induced immune activation. Use of estrogens in feminizing hormone therapy (FHT) may enhance inflammatory responses and the risk of cardiovascular mortality in TW. Despite this, the immunomodulatory effects of estrogen use in TW with HIV have been inadequately explored.

Methods

As an in vitro model for FHT, cryopreserved PBMCs (cryoPBMCs) from HIV negative (HIV-), HIV+ ART-suppressed (HIV+SP), and HIV+ ART-unsuppressed (HIV+USP) cisgender men were cultured overnight in the presence of 17-β estradiol or 17-α ethinylestradiol with and without the TLR4 agonist LPS or the TLR8 agonist ssPolyU. Monocyte activation (CD69, HLA-DR, CD38) was assessed by flow cytometry. Cytokine levels (IL-6, TNF-α, IL-1β, and IL-10) were measured in cell culture supernatants by Legendplex. Levels of phosphorylated TLR signaling molecules (JNK, MAPK p38) were assessed by Phosflow. Plasma levels of immune activation biomarkers (LPS-binding protein, monocyte activation markers sCD14 and sCD163, and inflammatory molecules IL-6 and TNF-α receptor I) were measured by ELISA.

Results

PBMCs from people with HIV (PWH) produced greater levels of inflammatory cytokines following exposure to LPS or ssPolyU compared to levels from cells of HIV- individuals. While estrogen exposure alone induced mild changes in immune activation, LPS-induced TLR4 activation was elevated with estrogen in cisgender men (CM) with HIV, increasing monocyte activation and inflammatory cytokine production (IL-6, TNF-α). Interestingly, testosterone inhibited LPS-induced cytokine production in CM regardless of HIV status. Plasma markers of immune activation and microbial translocation (e.g., sCD14, sCD163, LPS-binding protein) were generally higher in PWH compared to HIV- CM, and these markers were positively associated with in vitro responsiveness to estrogen and LPS in CM with HIV.

Conclusions

Our in vitro data suggest that estrogen exposure may enhance innate immune activation in PWH. Further examination is needed to fully understand the complex interactions of FHT, HIV, and CVD in TW, and determine optimal FHT regimens or supplementary treatments aimed at reducing excess immune activation.

Immune correlates of cardiovascular co-morbidity in HIV infected participants from South India

BACKGROUND

Understanding the immune correlates of cardiovascular disease (CVD) risk in HIV infection is an important area of investigation in the current era of aging with HIV infection. Less is known about CVD risk and HIV infection in developing nations where additional risk factors may be playing a role in the CVD development. In this study, we assessed the effects of systemic inflammation, microbial translocation (MT), T cell immune activation (IA), and nadir CD4 counts on cardiac function and arterial stiffness as markers of subclinical atherosclerosis in HIV-infected individuals.

METHODS

People with HIV (PWH) who were ART naïve (n = 102) or virally suppressed on ART (n = 172) were stratified on nadir CD4 counts and compared to HIV-uninfected controls (n = 64). Determination was made of cardiac function via radial pulse wave and carotid intima thickness (C-IMT) measurements. Plasma biomarkers of inflammation and MT by ELISA or multiplex assays, and immune activation (IA) of T cells based HLA-DR and CD38 expression were investigated by flow cytometry. T-test, Mann-Whitney U test, and Spearman correlation were used to analyze study parameters.

RESULTS

Reduction in cardiac function with lower cardiac ejection time (p < 0.001), stroke volume (p < 0.001), cardiac output (p = 0.007), higher arterial stiffness (p < 0.05) were identified in ART-naïve participants, compared to PWH on ART (p < 0.05). No significant difference in C-IMT values were noted. Higher inflammatory and MT markers were found in the ART-naïve group compared to treated group who were comparable to uninfected participants, except for having higher TNF-α (p < 0.001) and sCD14 (p < 0.001). Immune activation of CD4 and CD8 T-cells was greater in ART-naïve participants compared to ART-treated and uninfected controls (p < 0.05). Lower nadir CD4 counts, higher inflammation, and higher MT predicted poor cardiac measures in the ART-naïve with nadir CD4 < 200cells/mm³ manifesting the highest arterial stiffness, and lowest cardiac function, whereas ART-treated, even with nadir < 200 cells/mm³ were similar to uninfected in these measures.

CONCLUSIONS

In HIV-infected individuals, initiation of ART even at nadir of < 200 cells/mm³ may prevent or reverse cardiovascular disease outcomes that are easily measurable in low income countries.

Association between inflammation and coagulation biomarkers and carotid atherosclerosis among treated people with HIV

Background

Atherosclerotic cardiovascular disease (CVD) is a common cause of morbidity among people with human immunodeficiency virus (PWH) who initiate antiretroviral therapy (ART). Little is known about the roles of inflammation in atherosclerotic CVD among PWH.

Methods

This cross-sectional evaluation included 178 PWH between 40 and 70 years on stable (>3 months) ART who were derived from the ongoing, prospective cohort for Comparative HIV and Aging Research in Taizhou (CHART), China, from February 2017 to August 2018. Carotid intima-media thickness (cIMT) ≥1 mm was considered as cIMT thickening indicative of atherosclerotic CVD. Plasma inflammation and coagulation biomarkers were quantified by a multiplex bead cytokine assay for 27 cytokines and enzyme-linked immunosorbent assay (ELISA) for soluble CD14 and D-dimer, respectively. We performed a series of multiparametric analyses of biomarkers and developed a composite score for atherosclerotic CVD assessment among PWH.

Results

Of 178 PWH, 53 (30.9%) had cIMT thickening. In multivariable logistic analysis adjusting for CVD and human immunodeficiency virus-specific risk factors, interleukin (IL)-4 (odds ratio [OR] = 19.0; 95% confidence interval [CI], 1.6–226.5), IL-7 (OR = 16.7; 95% CI, 1.8–151.7), IL-10 (OR = 11.9; 95% CI, 2.0–72.1), and D-dimer (OR = 3.1; 95% CI, 1.0–10.1) were significantly associated with cIMT thickening. We also developed a composite score incorporating markers (IL-7, IL-10, D-dimer, and hypertension) that accurately evaluated atherosclerotic CVD.

Conclusions

The associations of IL-4, IL-7, IL-10, and D-dimer with atherosclerosis underscores research needs to further understand the inflammatory mechanisms in the pathogenesis of atherosclerosis CVD among treated PWH. The composite score for atherosclerotic CVD assessment could be useful for risk stratification in PWH.

Menopause Is Associated With Immune Activation in Women With HIV

BACKGROUND

Persistent immune activation due to gut barrier dysfunction is a suspected cause of morbidity in HIV, but the impact of menopause on this pathway is unknown.

METHODS

In 350 women with HIV from the Women's Interagency HIV Study, plasma biomarkers of gut barrier dysfunction (intestinal fatty acid binding protein; IFAB), innate immune activation (soluble CD14 and CD163; sCD14, sCD163), and systemic inflammation (interleukin-6 and tumor necrosis factor receptor 1; IL-6, TNFR1) were measured at 674 person-visits spanning ≤2 years.

RESULTS

Menopause (post- vs premenopausal status) was associated with higher plasma sCD14 and sCD163 in linear mixed-effects regression adjusting for age and other covariates (β = 161.89 ng/mL; 95% confidence interval [CI], 18.37-305.41 and 65.48 ng/mL, 95% CI, 6.64-124.33, respectively); but not with plasma IFAB, IL-6, or TNFR1. In piece-wise linear mixed-effects regression of biomarkers on years before/after the final menstrual period, sCD14 increased during the menopausal transition by 250.71 ng/mL per year (95% CI, 16.63-484.79; P = .04), but not in premenopausal or postmenopausal periods.

CONCLUSIONS

In women with HIV, menopause may increase innate immune activation, but data did not support an influence on the gut barrier or inflammation. Clinical implications of immune activation during menopausal transition warrant further investigation.

Effect of gluten-free diet on levels of soluble CD14 and lipopolysaccharide-binding protein in adult patients with celiac disease

Introduction

Celiac disease (CD) is an autoimmune enteropathy triggered by gluten ingestion in genetically susceptible individuals. In CD, activation of the immune response causes damage of the intestinal mucosa, and a gluten-free diet (GFD) is the only available therapy. Intestinal damage can lead to an increase in the circulation of components of bacteria from the intestinal lumen, such as lipopolysaccharide (LPS). Soluble CD14 (sCD14) and lipopolysaccharide-binding protein (LBP) participate in the recognition of LPS, and their levels are altered in different pathologies. In the present study, the circulating levels of sCD14 and LBP from untreated CD patients were evaluated and compared to CD patients on a GFD and controls.

Material and methods

In total seventy-two adult patients with CD, twenty-three untreated CD patients and forty-nine on a GFD were included. In addition, fifty-five healthy individuals were included as controls. Additionally, the effect of LPS on sCD14 production by both normal and inflamed intestinal tissue culture was explored.

Results

Serum levels of sCD14 were found to be significantly increased in untreated CD patients compared to patients on a GFD and controls. In addition, we found that LPS induced the production of sCD14 by biopsies of intestinal tissue from untreated CD patients.

Conclusions

The data from this study show that circulating levels of sCD14 are increased in the untreated CD patients compared to patients on a GFD. Our data show that LPS induces the production of sCD14 by the intestinal tissue from untreated CD patients.

Effect of aspirin on HIV disease progression among HIV-infected individuals initiating antiretroviral therapy: study protocol for a randomised controlled trial

INTRODUCTION

An increase in cardiovascular disease (CVD) among people living with HIV infection is linked to platelet and immune activation, a phenomenon unabolished by antiretroviral (ARV) drugs alone. In small studies, aspirin (acetylsalicylic acid [ASA]) has been shown to control immune activation, increase CD4+ count, halt HIV disease progression and reduce HIV viral load (HVL). We present a protocol for a larger ongoing randomised placebo controlled trial on the effect of an addition of ASA to ARV drugs on HIV disease progression.

METHODS AND ANALYSIS

A single-centre phase IIA double-blind, parallel-group randomised controlled trial intends to recruit 454 consenting ARV drug-naïve, HIV-infected adults initiating ART. Participants are randomised in blocks of 10 in a 1:1 ratio to receive, in addition to ARV drugs, 75 mg ASA or placebo for 6 months. The primary outcome is the proportion of participants attaining HVL of <50 copies/mL by 8, 12 and 24 weeks. Secondary outcomes include proportions of participants with HVL of >1000 copies/mL at week 24, attaining a >30% rise of CD4 count from baseline value at week 12, experiencing adverse events, with normal levels of biomarkers of platelet and immune activation at weeks 12 and 24 and rates of morbidity and all-cause mortality. Intention-to-treat analysis will be done for all study outcomes.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from institutional and national ethics review committees. Findings will be submitted to peer-reviewed journals and presented in scientific conferences.

TRIAL REGISTRATION NUMBER

PACTR202003522049711.

Implications for the role of lipopolysaccharide in the development of atherosclerosis

Mounting scientific evidence over decades has established that atherosclerosis is a chronic inflammatory disorder. Among the potentially critical sources of vascular inflammation during atherosclerosis are the components of pathogenic bacteria, especially lipopolysaccharide (LPS). Toll-like receptor (TLR)-4, expressed on different inflammatory cells involved with the recognition of bacterial LPS, has been recognized to have mutations that are prevalent in a number of ethnic groups. Such mutations have been associated with a decreased risk of atherosclerosis. In addition, epidemiological investigations have proposed that LPS confers a risk factor for the development of atherosclerosis. Gram-negative bacteria are the major source of LPS in an individual's serum, which may be generated during subclinical infections. The major cell receptors on inflammatory cells involved in the pathogenesis of atherosclerosis, like macrophages, monocytes, and dendritic cells (DCs), are CD14, MD-2, and LPS binding protein (LBP). These receptors have been blamed for the development of atherosclerosis through dysregulated activation following LPS recognition. Lipoproteins may also play a role in modulating the LPS-induced inflammatory events during atherosclerosis development. In this review article, we attempt to clarify the role of LPS in the initiation and progression of atherosclerotic lesion development.

Incorporating Frailty Into the Pooled Cohort Equations to Predict Cardiovascular Disease Among Persons With HIV

BACKGROUND

The 2013 Pooled Cohort Equations (PCEs) have underestimated cardiovascular disease (CVD) events among persons with HIV (PWH). We evaluate whether the addition of frailty improves PCE's ability to estimate CVD risk among aging PWH.

SETTING

Multicenter study.

METHODS

We assessed baseline frailty and 5-year atherosclerotic CVD risk using PCEs for participants in the AIDS Clinical Trials Group A5322 observational study. The primary outcome was incident CVD. We fit Cox proportional hazards regression models for incident CVD with (1) PCEs alone and (2) PCEs and frailty together (which included separate models for frailty score, frailty status, slow gait speed, and weak grip strength). We evaluated discrimination ability for the models with and without frailty by comparing their areas under receiver operating characteristic curve (AUCs) and Uno C-statistics, as well as by calculating the net reclassification improvement and integrated discrimination improvement.

RESULTS

The analysis included 944 A5322 participants (759 men, 185 women, median age 50 years, 47% White non-Hispanic). Thirty-nine participants experienced incident CVD during the study period. PCEs predicted 5-year CVD risk in all models. With frailty score, frailty status, slow gait speed, or weak grip strength added, the AUC and C-statistics were relatively unchanged, and the NRI and integrated discrimination improvement indicated little improvement in model discrimination. However, frailty score independently predicted CVD risk [frailty score: hazard ratio = 1.30, 95% confidence interval (CI) = 1.00 to 1.70, P = 0.05].

CONCLUSIONS

Frailty did not improve the predictive ability of PCEs. Baseline PCEs and frailty score independently predicted CVD. Incorporation of frailty assessment into clinical practice may provide corroborative and independent CVD risk estimation.

Switching from boosted PIs to dolutegravir decreases soluble CD14 and adiponectin in high cardiovascular risk people living with HIV

BACKGROUND

Switching from boosted PIs to dolutegravir in people living with HIV (PLWH) with high cardiovascular risk improved plasma lipids at 48 weeks in the NEAT022 trial. Whether this strategy may have an impact on cardiovascular biomarkers is unknown.

METHODS

We assessed 48 week changes in biomarkers associated with inflammation, endothelial dysfunction, monocyte immune activation, oxidation, insulin resistance, hypercoagulability, heart failure, myocardial injury, and glomerular and tubular kidney injury.

RESULTS

Of 415 PLWH randomized in the NEAT022 study, 313 (75.4%) remained on allocated therapy and had paired samples available. Soluble CD14 (-11%, P < 0.001) and adiponectin (-11%, P < 0.001) significantly declined and high-sensitive C-reactive protein (-13%, P = 0.069) and oxidized LDL (-13%, P = 0.084) tended to decrease with dolutegravir. Switching to dolutegravir remained significantly associated with soluble CD14 and adiponectin reductions after adjustment for baseline variables. There were inverse correlations between soluble CD14 and CD4 count changes (P = 0.05), and between adiponectin and BMI changes (P < 0.001).

CONCLUSIONS

Switching from boosted PIs to dolutegravir in PLWH with high cardiovascular risk led to soluble CD14 and adiponectin reductions at 48 weeks. While decreasing soluble CD14 may entail favourable health effects in PLWH, adiponectin reduction may reflect less insulin sensitivity associated with weight gain.

Changes in Immune Activation During Pregnancy and the Postpartum Period in Treated HIV Infection

Background

Pregnant women with HIV (PWWH) have high postpartum morbidity and mortality from infections like tuberculosis. Immunologic changes during pregnancy and postpartum periods may contribute to these risks, particularly the immunoregulatory kynurenine pathway of tryptophan catabolism, which contributes to both HIV and tuberculosis pathogenesis and increases in the early postpartum period.

Methods

Women with HIV initiating antiretroviral therapy (ART) in the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort who were pregnant at enrollment or became pregnant during observation were studied (n = 54). Plasma kynurenine/tryptophan (KT) ratio, soluble CD14 (sCD14), sCD163, sCD27, interferon-inducible protein 10 (IP-10), D-dimer, interleukin-6, and intestinal fatty-acid binding protein levels were assessed through the first year of ART and at 3-month intervals throughout pregnancy and 1 year postpartum. Biomarker changes were assessed with linear mixed models adjusted for ART duration. Hemoglobin concentration changes were used to estimate pregnancy-related changes in plasma volume.

Results

The median pre-ART CD4 count was 134. D-dimer increased through the third trimester before returning to baseline postpartum, while most other biomarkers declined significantly during pregnancy, beyond what would be expected from pregnancy-associated plasma volume expansion. IP-10 and sCD14 remained suppressed for at least 12 months postpartum. KT ratio was the only biomarker that increased above prepregnancy baseline postpartum (mean + 30%; P < .001) and remained higher than baseline for ≥9 months (P ≤ .045 for all time points).

Conclusions

Several immune activation markers decline during pregnancy and remain suppressed postpartum, but the kynurenine pathway of tryptophan catabolism increases above baseline for ≥9 months postpartum. The mechanisms underlying postpartum kynurenine pathway activity are incompletely understood but may contribute to increased tuberculosis risk in this setting.

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.

Gastrointestinal Dysfunction and HIV Comorbidities

PURPOSE OF REVIEW

Gut dysfunction and resulting chronic low-grade inflammation have been linked to metabolic and chronic diseases in the general population. In this review, we present recently published studies of HIV-associated gut dysfunction and comorbidities including obesity, diabetes, cardiovascular disease, liver disease, and neurocognitive disease.

RECENT FINDINGS

Biomarkers of microbial translocation, dysbiosis, or intestinal epithelial integrity have been used to investigate relationships between HIV-associated gut dysfunction and metabolic, cardiovascular, and neurologic complications. Many studies point to worsened comorbidities associated with gut dysfunction in people with HIV (PWH), but some studies show mixed results, and thus, the data are still inconclusive and limited to surrogate biomarkers rather than direct intestinal assessments. Inflammation and immune activation stemming from changes in intestinal epithelial integrity and dysbiosis are present in PWH and relate to metabolic, cardiovascular, and neurologic complications of HIV. However, future investigations, especially future studies that directly assess intestinal pathology, are needed to investigate the direct contributory role of gastrointestinal dysfunction to comorbidities of HIV.

Antiretroviral therapy reduces but does not normalize immune and vascular inflammatory markers in adults with chronic HIV infection in Kenya

INTRODUCTION

Markers of monocyte/macrophage activation and vascular inflammation are associated with HIV-related cardiovascular diseases (CVD) and mortality. We compared these markers among African people living with HIV (PLWH) and HIV-negative adults, and examined risk factors associated with elevated biomarkers (>75th percentile) in PLWH on antiretroviral therapy (ART).

DESIGN

Cross-sectional study.

METHODS

We measured serum concentrations of a gut integrity biomarker (intestinal-fatty acid binding protein), monocyte/macrophage activation biomarkers (soluble CD14 and CD163), and vascular inflammation biomarkers [soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular adhesion molecule 1 (sVCAM-1)]. We assessed the relationship of these inflammatory parameters with HIV, using logistic regression adjusting for traditional CVD risk factors.

RESULTS

Among the 541 participants, median age was 43 years and half were female. Among 275 PLWH, median CD4 T-cell count and duration of ART use was 509 cells/μl and 8 years, respectively. PLWH had significantly higher prevalence of elevated inflammatory biomarkers compared with HIV-negative individuals even after adjustment for traditional CVD risk factors. Compared with individuals without HIV, the prevalence of elevated biomarkers was highest among persons with detectable viral load and CD4 T-cell counts 200 cells/μl or less. In a subanalysis among PLWH, nadir CD4 T-cell count 200 cells/μl or less was associated with elevated soluble CD14 (sCD14); dyslipidemia with elevated sCD14, sICAM-1, and sVCAM-1; and overweight/obesity with reduced sCD14. Longer ART exposure (>4 years) was associated with reduced sVCAM-1 and sICAM-1.

CONCLUSION

HIV and not traditional CVD risk factors is a primary contributor of monocyte/macrophage activation and inflammation despite ART. Anti-inflammatory therapies in addition to ART may be necessary to reduce these immune dysregulations and improve health outcomes of African PLWH.

Statin effect on coronary calcium distribution, mass and volume scores and associations with immune activation among HIV+ persons on antiretroviral therapy

BACKGROUND

Inflammation has been associated with whole heart coronary artery calcification (CAC) among people with HIV (PWH) on antiretroviral therapy (ART); however, prior studies have not evaluated the distribution of calcium or separated mass versus volume scores, which are differentially associated with clinical events in the general population. Statins may also have a greater effect on CAC mass compared with volume.

METHODS

147 PWH were randomized 1:1 to rosuvastatin 10 mg or placebo and followed for 96 weeks. We re-analysed coronary calcium scans from 0, 48 and 96 weeks to determine mass and volume scores and measures of CAC diffusivity. Mixed effects models and generalized estimating equations were used to examine longitudinal associations of CAC with treatment and biomarkers.

RESULTS

Median age at study entry was 46 years; 78% were male and 68% African American. Median CD4+ was 613 and half were on protease inhibitors. Randomization to statin therapy was not associated with a change in mass score, volume score, number of involved vessels or diffusivity index (all P>0.1). Soluble CD14 was associated with the presence of CAC (P=0.05) and borderline associated with number of involved vessels (P=0.07) across all three time points.

CONCLUSIONS

In PWH on ART, moderate intensity rosuvastatin does not appear to have a significant effect on volume, mass or regional distribution of CAC over 96 weeks. We extend previous cross-sectional observations to show that soluble CD14 is associated with whole heart CAC over time and independently of age and systolic blood pressure.

Block-And-Lock: New Horizons for a Cure for HIV-1

HIV-1/AIDS remains a global public health problem. The world health organization (WHO) reported at the end of 2019 that 38 million people were living with HIV-1 worldwide, of which only 67% were accessing antiretroviral therapy (ART). Despite great success in the clinical management of HIV-1 infection, ART does not eliminate the virus from the host genome. Instead, HIV-1 remains latent as a viral reservoir in any tissue containing resting memory CD4⁺ T cells. The elimination of these residual proviruses that can reseed full-blown infection upon treatment interruption remains the major barrier towards curing HIV-1. Novel approaches have recently been developed to excise or disrupt the virus from the host cells (e.g., gene editing with the CRISPR-Cas system) to permanently shut off transcription of the virus (block-and-lock and RNA interference strategies), or to reactivate the virus from cell reservoirs so that it can be eliminated by the immune system or cytopathic effects (shock-and-kill strategy). Here, we will review each of these approaches, with the major focus placed on the block-and-lock strategy.

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.

Sex Differences in the Treatment of HIV

PURPOSE OF REVIEW

Biological and societal influences are different for men and women leading to different HIV outcomes and related infectious and non-infectious complications. This review evaluates sex differences in the epidemiology and immunological response to HIV and looks at major complications and coinfections, as well as care delivery systems focusing on low- and middle-income countries (LMICs) where most people with HIV live.

RECENT FINDINGS

More women than men access testing and treatment services in LMIC; women are more likely to be virologically suppressed in that environment. There is a growing recognition that the enhanced immunological response to several pathogens including HIV may result in improved outcomes for infectious comorbidities but may result in a greater burden of non-communicable diseases. Men and women have different requirements for HIV care. Attention to these differences may improve outcomes for all.

Managing HIV-associated inflammation and ageing in the era of modern ART

OBJECTIVES

This paper aims to address the concerns around ongoing immune activation, inflammation, and resistance in those ageing with HIV that represent current challenges for clinicians.

METHODS

Presentations at a symposium addressing issues of ageing with HIV infection were reviewed and synthesised.

RESULTS

The changing natural history and demographics of human immunodeficiency virus (HIV)-infected individuals means new challenges in contemporary management. In the early years of the epidemic,management was focussed on acute, potentially life-threatening AIDS-related complications. From initial monotherapy with first-generation antiretroviral therapy (ART), the development of combination highly active ART (HAART) allowed HIV control but ART toxicities, treatment adherence and drug resistance emerged as major issues. Today, the availability of potent and tolerable ART has made viral suppression achievable in most people living with HIV (PLHIV), and clinicians are confronted with managing a chronic condition among an ageing population. The combination of diseases of ageing and the co-morbidities associated with HIV-infection, even when well controlled, results in a complex set of challenges for many older PLHIV. There is a growing appreciation that many non-AIDS-related co-morbidities are caused, at least in part, by persistent, low-grade immune activation, inflammation, and hypercoagulability, despite suppressive ART.

CONCLUSIONS

In order to further improve HIV management, it is important to understand the enduring effects of chronically suppressed HIV infection, the potential contribution of these factors to the ageing process, the possibility of drug resistance, and the impact of different treatment strategies, including early ART initiation.

Endothelial Dysfunction Is Related to Monocyte Activation in Antiretroviral-Treated People With HIV and HIV-Negative Adults in Kenya

BACKGROUND

Residual monocyte activation may contribute to increased risk for endothelial dysfunction and subsequent atherosclerotic cardiovascular diseases (CVDs) among people with HIV (PWH) on antiretroviral therapy (ART). We examined the relationship between monocyte activation and endothelial activation in PWH in Kenya.

METHODS

Serum levels of markers of endothelial activation (soluble/circulating intercellular [sICAM-1] and vascular [sVCAM-1] cell adhesion molecule-1), intestinal barrier dysfunction (intestinal fatty acid binding protein [I-FABP]), and monocyte activation (soluble CD14 [sCD14]) were measured in 275 PWH on ART and 266 HIV-negative persons. Linear regression was used to evaluate associations, adjusting for demographic and traditional CVD risk factors.

RESULTS

Among 541 participants, the median age was 43 years, 50% were female, and most PWH were virally suppressed (97%). sICAM-1 and sVCAM-1 levels were significantly higher in PWH than in HIV-negative participants (P < .001 for both). After further adjustment for traditional CVD risk factors, HIV infection remained associated with 49% (95% CI, 33% to 67%) greater sICAM-1 and 30% (95% CI, 14% to 48%) greater sVCAM-1 relative to uninfected controls. Adjustment for sCD14 substantially attenuated the difference between PWH and HIV-negative individuals. In a stratified analysis of PWH, both sICAM-1 and sVCAM-1 were positively associated with sCD14 (P < .001).

CONCLUSIONS

Despite viral suppression, African PWH have evidence of enhanced endothelial activation associated with sCD14, suggesting that monocyte activation plays a role in atherosclerotic plaque development. Future studies are needed to determine mechanistic pathways leading to monocyte activation in this population.

A Randomized, Double-blinded, Placebo-controlled Trial of Sitagliptin for Reducing Inflammation and Immune Activation in Treated and Suppressed Human Immunodeficiency Virus Infection

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inhibitors have pleotropic anti-inflammatory and immune regulatory effects in addition to glucoregulation. We evaluated inflammation and immune markers in suppressed human immunodeficiency virus (HIV) infection during treatment with the DPP-4 inhibitor sitagliptin.

METHODS

Virologically suppressed adults with HIV without diabetes on stable antiretroviral therapy (ART) with ≥100/μL CD4 cells were randomized to 16 weeks of sitagliptin 100 mg/day vs placebo in a multicenter trial. The primary endpoint was the change in plasma soluble CD14 (sCD14) from baseline to week 15-16.

RESULTS

Ninety participants were randomized, and 42 from each arm were included in per-protocol analyses. Participants were 45% non-Hispanic white, 38% non-Hispanic black, and 15% Hispanic, with a median age of 51 years; 83% were male; and the median CD4 count was 602 cells/μL. At week 15-16, there was no difference in sCD14 change between the 2 arms (P = .69). Relative to placebo, the sitagliptin arm had 47% greater decline in CXCL10 (95% confidence interval, -57% to -35%) at week 15 (P < .001). There were no significant between-arm differences in other soluble biomarkers, total CD4 and CD8 counts, or markers of lymphocyte or monocyte activation. Sitagliptin was well tolerated.

CONCLUSIONS

Sixteen weeks of sitagliptin had no effect on sCD14 levels in virologically suppressed participants with HIV. CXCL10, a chemokine involved in atherogenesis that predicts non-AIDS events during ART, declined markedly with sitagliptin. This suggests that DPP-4 inhibition has the potential to reduce cardiovascular morbidity in treated HIV infection.

CLINICAL TRIALS REGISTRATION

NCT01426438.

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.

Lipids, biomarkers, and subclinical atherosclerosis in treatment-naive HIV patients starting or not starting antiretroviral therapy: Comparison with a healthy control group in a 2-year prospective study

Objective

To assess the effect of HIV infection and combined antiretroviral therapy (c-ART) on various proatherogenic biomarkers and lipids and to investigate their relationship with subclinical atherosclerosis in a cohort of treatment-naive HIV-infected patients.

Methods

We performed a prospective, comparative, multicenter study of 2 groups of treatment-naive HIV-infected patients (group A, CD4>500 cells/μL, not starting c-ART; and group B, CD4<500 cells/μL, starting c-ART at baseline) and a healthy control group. Laboratory analyses and carotid ultrasound were performed at baseline and at months 12 and 24. The parameters measured were low-density lipoprotein (LDL) particle phenotype, lipoprotein-associated phospholipase A2 (Lp-PLA2), interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), sCD14, sCD163, monocyte chemoattractant protein-1(MCP-1), and asymmetric dimethylarginine (ADMA). A linear mixed model based on patient clusters was used to assess differences in biomarkers between the study groups and over time.

Results

The study population comprised 62 HIV-infected patients (group A, n = 31; group B, n = 31) and 22 controls. Age was 37 (30–43) years, and 81% were men. At baseline, the HIV-infected patients had a worse LDL particle phenotype and higher plasma concentration of sCD14, sCD163, hs-CRP, and LDL-Lp-PLA2 than the controls. At month 12, there was an increase in total cholesterol (p = 0.002), HDL-c (p = 0.003), and Apo A-I (p = 0.049) and a decrease in sCD14 (p = <0.001) and sCD163 (p<0.001), although only in group B. LDL particle size increased in group B at month 24 (p = 0.038). No changes were observed in group A or in the healthy controls. Common carotid intima-media thickness increased in HIV-infected patients at month 24 (Group A p = 0.053; group B p = 0.048). Plasma levels of sCD14, sCD163, and hs-CRP correlated with lipid values.

Conclusions

In treatment-naive HIV-infected patients, initiation of c-ART was associated with an improvement in LDL particle phenotype and inflammatory/immune biomarkers, reaching values similar to those of the controls. HIV infection was associated with progression of carotid intima-media thickness.

Peripheral innate immune and bacterial signals relate to clinical heterogeneity in Parkinson's disease

The innate immune system is implicated in Parkinson's disease (PD), but peripheral in-vivo clinical evidence of the components and driving mechanisms involved and their relationship with clinical heterogeneity and progression to dementia remain poorly explored. We examined changes in peripheral innate immune-related markers in PD cases (n = 41) stratified according to risk of developing early dementia. 'Higher Risk'(HR) (n = 23) and 'Lower Risk' (LR) (n = 18) groups were defined according to neuropsychological predictors and MAPT H1/H2 genotype, and compared to age, gender and genotype-matched controls. Monocyte subsets and expression of key surface markers were measured using flow cytometry. Serum markers including alpha-synuclein, inflammasome-related caspase-1 and bacterial translocation-related endotoxin were measured using quantitative immuno-based assays. Specific markers were further investigated using monocyte assays and validated in plasma samples from a larger incident PD cohort (n = 95). We found that classical monocyte frequency was elevated in PD cases compared to controls, driven predominantly by the HR group, in whom Toll-Like Receptor (TLR)4+ monocytes and monocyte Triggering Receptor Expressed on Myeloid cells-2 (TREM2) expression were also increased. Monocyte Human Leukocyte Antigen (HLA)-DR expression correlated with clinical variables, with lower levels associated with worse cognitive/motor performance. Notably, monocyte changes were accompanied by elevated serum bacterial endotoxin, again predominantly in the HR group. Serum alpha-synuclein and inflammasome-related caspase-1 were decreased in PD cases compared to controls regardless of group, with decreased monocyte alpha-synuclein secretion in HR cases. Further, alpha-synuclein and caspase-1 correlated positively in serum and monocyte lysates, and in plasma from the larger cohort, though no associations were seen with baseline or 36-month longitudinal clinical data. Principal Components Analysis of all monocyte and significant serum markers indicated 3 major components. Component 1 (alpha-synuclein, caspase-1, TLR2+ monocytes) differentiated PD cases and controls in both groups, while Component 2 (endotoxin, monocyte TREM2, alpha-synuclein) did so predominantly in the HR group. Component 3 (classical monocytes, alpha-synuclein) also differentiated cases and controls overall in both groups. These findings demonstrate that systemic innate immune changes are present in PD and are greatest in those at higher risk of rapid progression to dementia. Markers associated with PD per-se (alpha-synuclein, caspase-1), differ from those related to cognitive progression and clinical heterogeneity (endotoxin, TREM2, TLR4, classical monocytes, HLA-DR), with mechanistic and therapeutic implications. Alpha-synuclein and caspase-1 are associated, suggesting inflammasome involvement common to all PD, while bacterial translocation associated changes may contribute towards progression to Parkinson's dementia. Additionally, HLA-DR-associated variations in antigen presentation/clearance may modulate existing clinical disease.

HIV-1 Persistence and Chronic Induction of Innate Immune Responses in Macrophages

A hallmark of HIV-1 infection is chronic inflammation, which plays a significant role in disease pathogenesis. Acute HIV infection induces robust inflammatory responses, which are insufficient to prevent or eliminate virus in mucosal tissues. While establishment of viral set-point is coincident with downregulation of acute innate responses, systemic inflammatory responses persist during the course of chronic HIV infection. Since the introduction of combination antiviral therapy (cART), most HIV-1⁺ individuals can suppress viremia under detection levels for decades. However, chronic immune activation persists and has been postulated to cause HIV associated non-AIDS complications (HANA). Importantly, inflammatory cytokines and activation markers associated with macrophages are strongly and selectively correlated with the incidence of HIV-associated neurocognitive disorder (HAND), cardiovascular dysfunctions (CVD) and other HANA conditions. In this review, we discuss the roles of macrophages in facilitating viral persistence and contributing to generation of persistent inflammatory responses.

Brief Report: Zinc Supplementation and Inflammation in Treated HIV

OBJECTIVE

In this study, we explored the effect of zinc supplementation on markers of inflammation and monocyte activation in antiretroviral therapy-treated HIV infection.

METHODS

This is a phase I open-labeled randomized double-arm study, exploring the efficacy and safety of zinc supplementation on inflammation in ≥18-year-old people living with HIV in the US, on stable antiretroviral therapy and with zinc levels ≤75 µg/dL in the last 60 days. Patients were randomized 1:1 to zinc gluconate capsules at a dose of 45 mg (low-dose), or 90 mg (high-dose) elemental zinc daily for 16 weeks. We assessed inflammatory and gut integrity biomarkers at baseline and 16 weeks.

RESULTS

Overall, a total of 52 participants were enrolled (25 participants in the low-dose arm and 27 participants in the high-dose arm). Median (Interquartile range) age was 49 (38, 60) years, 77% were men and 73% were African Americans. At baseline, median zinc levels were 73 (64, 86) µg/dL. Median circulating zinc levels increased to 91 µg/dL in the low-dose arm and to 100 µg/dL in the high-dose arm. Overall, 48%-60% of participants experienced a reduction in biomarkers levels. The margin of reduction ranged between 8% and 21%. This change was meaningful with large effect size (Cohen D ranging from 5 to 19).

CONCLUSIONS

In this pilot study, we found that zinc supplementation is effective at increasing circulating zinc levels. In addition, our findings provide novel data suggesting that zinc can affect a biological signature in people living with HIV and modulate biomarkers associated with clinical comorbidities.

A therapeutic HIV-1 vaccine reduces markers of systemic immune activation and latent infection in patients under highly active antiretroviral therapy

HIV infection is characterized by chronic immune activation and the establishment of a pool of latently infected cells. Antiretroviral therapy (ART) can suppress viral load to undetectable levels in peripheral blood by standard measure, however immune activation/chronic inflammation and latent infection persist and affect quality of life. We have now shown that a novel therapeutic HIV vaccine consisting of replication-defective HIV (HIVAX), given in the context of viral suppression under ART, can reduce both immune activation/chronic inflammation and latent infection. Immune activation, as measured by percent of CD8 + HLA-DR + CD38 + T cells, approached levels of healthy controls at week 16 following vaccination. Reduced immune activation was accompanied by a reduction in pro-inflammatory cytokines and peripheral α4β7 + plasmacytoid DC (a marker of mucosal immune activation). Levels of both HIV-1 DNA and 2-LTR circles were reduced at week 16 following vaccination, suggesting HIVAX can impact HIV-1 latency and reduce viral replication. Surprisingly, reduced immune activation/chronic inflammation was accompanied by an increase in the percent of memory CD4 + T cells expressing markers PD-1 and TIM-3. In addition, evaluation of HIV-1 Gag-specific CD4 + T cells for expression of 96 T cell related genes pre- and post-therapy revealed increased expression of a number of genes involved in the regulation of immune activation, T cell activation, and antiviral responses. Overall this study provides evidence that vaccination with HIVAX in subjects under long term antiviral suppression can reduce immune activation/chronic inflammation and latent infection (Clinicaltrials.gov, identifier NCT01428596).

The Opioid Epidemic: Impact on Inflammation and Cardiovascular Disease Risk in HIV

PURPOSE OF REVIEW

People infected with HIV through injection drug use are more likely to experience progression to AIDS, death due to AIDS, and all-cause mortality even when controlling for access to care and antiretroviral therapy. While high-risk behavior and concurrent infections most certainly are contributors, chronic immune activation, downstream metabolic comorbidities may play an important role.

RECENT FINDINGS

Altered intestinal integrity plays a major role in HIV-related immune activation and microbial translocation markers are heightened in active heroin users. Additionally, greater injection frequency drives systemic inflammation and is associated with HIV viral rebound. Finally, important systemic inflammation markers have been linked with frailty and mortality in people who inject drugs with and without concurrent HIV infection. Heroin use may work synergistically with HIV infection to cause greater immune activation than either factor alone. Further research is needed to understand the impact on downstream metabolic comorbidities including cardiovascular disease. Medication-assisted treatment for opioid use disorder with methadone or buprenorphine may ameliorate some of this risk; however, there is presently limited research in humans, including in non-HIV populations, describing changes in immune activation on these treatments which is of paramount importance for those with HIV infection.

Subclinical cardiovascular disease in HIV controller and long-term nonprogressor populations

OBJECTIVES

Elite controllers (ECs), viraemic controllers (VCs), and long-term nonprogressors (LTNPs) control HIV viral replication or maintain CD4 T-cell counts without antiretroviral therapy, but may have increased cardiovascular disease (CVD) risk compared to HIV-uninfected persons. We evaluated subclinical carotid and coronary atherosclerosis and inflammatory biomarker levels among HIV controllers, LTNPs and noncontrollers and HIV-uninfected individuals in the Multicenter AIDS Cohort Study (MACS) and the Women's Interagency HIV Study (WIHS).

METHODS

We measured carotid plaque presence and common carotid artery intima-media thickness (IMT) in 1729 women and 1308 men, and the presence of coronary artery calcium and plaque in a subgroup of men. Associations between HIV control category and carotid and coronary plaque prevalences were assessed by multivariable regression analyses adjusting for demographics and CVD risk factors. Serum inflammatory biomarker concentrations [soluble CD163 (sCD163), soluble CD14 (sCD14), galectin-3 (Gal-3), galectin-3 binding protein (Gal-3BP) and interleukin (IL)-6] were measured and associations with HIV control category assessed.

RESULTS

We included 135 HIV controllers (30 ECs) and 135 LTNPs in the study. Carotid plaque prevalence and carotid IMT were similar in HIV controllers, LTNPs and HIV-uninfected individuals. HIV controllers and LTNPs had lower prevalences of carotid plaque compared to viraemic HIV-infected individuals. The prevalence of coronary atherosclerosis was similar in HIV controllers/LTNPs compared to HIV-uninfected and viraemic HIV-infected men. Controllers and LTNPs had higher concentrations of sCD163 and sCD14 compared to HIV-uninfected persons.

CONCLUSIONS

Subclinical CVD was similar in HIV controllers, LTNPs and HIV-uninfected individuals despite elevated levels of some inflammatory biomarkers. Future studies of HIV controllers and LTNPs are needed to characterize the risk of CVD among HIV-infected persons.

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

OBJECTIVES

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

DESIGN

Longitudinal observational study of 118 treated and virologically suppressed individuals.

METHODS

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

RESULTS

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

CONCLUSION

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

Monocytes from men living with HIV exhibit heightened atherogenic potential despite long-term viral suppression with antiretroviral therapy

OBJECTIVE

People living with HIV have an increased risk of cardiovascular disease (CVD) despite effective antiretroviral therapy (ART). Monocytes play a key role in the early stages of atherosclerosis-driven CVD by forming lipid-laden foam cells within artery walls. HIV infection potentiates foam cell formation ex vivo, but the mechanisms contributing to this are not known.

METHODS

We investigated the atherosclerosis-promoting potential of monocytes from 39 virologically suppressed men living with HIV (MLHIV) on ART and no evidence of CVD, and 25 HIV-uninfected controls of comparable age, sex, smoking status and CVD risk.

RESULTS

Despite absence of clinical atherosclerosis in both MLHIV and uninfected cohorts (evidenced by a carotid intima-media thickness of 0.6 mm for both groups; P = 0.254), monocytes from MLHIV showed increased potential to form atherosclerosis-promoting foam cells compared with controls in an ex-vivo assay (36.6% vs. 27.6%, respectively, P = 0.003). Consistent with observations of persistent inflammation and immune/endothelial activation in ART-treated HIV infection, levels of soluble tumour necrosis factor receptor II, CXCL10 and soluble VCAM-1 were elevated in MLHIV (P ≤ 0.005 for all), but were not significantly associated with foam cell formation. Foam cell formation was associated with an impaired ability of monocytes to undergo reverse transmigration, and a reduced ability to efflux cholesterol ex vivo (P < 0.05 for both). Importantly, foam cell formation declined significantly with duration of viral suppression (P = 0.004).

CONCLUSION

These findings highlight the persistence of HIV-related changes to the atherogenic potential of monocytes despite long-term viral suppression, and provide insights into mechanisms potentially driving increased CVD in ART-treated HIV infection.

HIV, Sexual Orientation, and Gut Microbiome Interactions

Recent studies have raised interest in the possibility that dysbiosis of the gut microbiome (i.e., the communities of bacteria residing in the intestine) in HIV-infected patients could contribute to chronic immune activation, and, thus, to elevated mortality and increased risk of inflammation-related clinical diseases (e.g., stroke, cardiovascular disease, cancer, long-bone fractures, and renal dysfunction) found even in those on effective antiretroviral therapy. Yet, to date, a consistent pattern of HIV-associated dysbiosis has not been identified. What is becoming clear, however, is that status as a man who has sex with men (MSM) may profoundly impact the structure of the gut microbiota, and that this factor likely confounded many HIV-related intestinal microbiome studies. However, what factor associated with MSM status drives these gut microbiota-related changes is unclear, and what impact, if any, these changes may have on the health of MSM is unknown. In this review, we outline available data on changes in the structure of the gut microbiome in HIV, based on studies that controlled for MSM status. We then examine what is known regarding the gut microbiota in MSM, and consider possible implications for research and the health of this population. Lastly, we discuss knowledge gaps and needed future studies.

Brief Report: Hazardous Cannabis Use and Monocyte Activation Among Methamphetamine Users With Treated HIV Infection

BACKGROUND

The use of stimulants, such as methamphetamine, has been associated with greater immune activation in treated HIV infection. However, relatively little is known about whether concomitant cannabis use is associated with lower immune activation among HIV-positive stimulant users.

SETTING

HIV-positive, sexual minority men with biologically confirmed, recent methamphetamine use were enrolled in San Francisco, CA.

METHODS

In total, 78 methamphetamine-using sexual minority men with an undetectable HIV viral load (<40 copies/mL) completed self-report measures of cannabis use and substance use disorder severity. Plasma biomarkers of monocyte activation (ie, sCD14 and sCD163) and intestinal barrier integrity (iFABP) were measured. The associations of hazardous cannabis use with these measurements were examined after adjusting for substance use disorder severity, age, antiretroviral therapy regimen, CD4 T-cell count, and interleukin-6.

RESULTS

Hazardous cannabis users had the highest mean sCD14 levels (2181 ng/mL) compared with nonhazardous users (1991 ng/mL) and nonusers (1859 ng/mL; P = 0.05). In adjusted analyses, greater cannabis use severity was associated with higher sCD14 compared with nonusers (unstandardized beta = 133.6 ng/mL, P = 0.03). Cannabis use severity was not significantly associated with sCD163 or iFABP.

CONCLUSIONS

Hazardous cannabis use is independently associated with elevations in a clinically relevant marker of immune activation in methamphetamine users with treated HIV.

The Impact of Human Immunodeficiency Virus Infection on Gut Microbiota α-Diversity: An Individual-level Meta-analysis

BACKGROUND

Whether human immunodeficiency virus (HIV) infection impacts gut microbial α-diversity is controversial. We reanalyzed raw 16S ribosomal RNA (rRNA) gene sequences and metadata from published studies to examine α-diversity measures between HIV-uninfected (HIV-) and HIV-infected (HIV+) individuals.

METHODS

We conducted a systematic review and individual level meta-analysis by searching Embase, Medline, and Scopus for original research studies (inception to 31 December 2017). Included studies reported 16S rRNA gene sequences of fecal samples from HIV+ patients. Raw sequence reads and metadata were obtained from public databases or from study authors. Raw reads were processed through standardized pipelines with use of a high-resolution taxonomic classifier. The χ2 test, paired t tests, and generalized linear mixed models were used to relate α-diversity measures and clinical metadata.

RESULTS

Twenty-two studies were identified with 17 datasets available for analysis, yielding 1032 samples (311 HIV-, 721 HIV+). HIV status was associated with a decrease in measures of α-diversity (P < .001). However, in stratified analysis, HIV status was associated with decreased α-diversity only in women and in men who have sex with women (MSW) but not in men who have sex with men (MSM). In analyses limited to women and MSW, controlling for HIV status, women displayed increased α-diversity compared with MSW.

CONCLUSIONS

Our study suggests that HIV status, sexual risk category, and gender impact gut microbial community α-diversity. Future studies should consider MSM status in gut microbiome analyses.