Monocytes expand with immune dysregulation and is associated with insulin resistance in older individuals with chronic HIV

Dynamics of peripheral T cell exhaustion and monocyte subpopulations in neurocognitive impairment and brain atrophy in chronic HIV infection

BACKGROUND

HIV-associated neurocognitive disorders (HAND) is hypothesized to be a result of myeloid cell-induced neuro-inflammation in the central nervous system that may be initiated in the periphery, but the contribution of peripheral T cells in HAND pathogenesis remains poorly understood.

METHODS

We assessed markers of T cell activation (HLA-DR + CD38+), immunosenescence (CD57 + CD28-), and immune-exhaustion (TIM-3, PD-1 and TIGIT) as well as monocyte subsets (classical, intermediate, and non-classical) by flow cytometry in peripheral blood derived from individuals with HIV on long-term stable anti-retroviral therapy (ART). Additionally, normalized neuropsychological (NP) composite test z-scores were obtained and regional brain volumes were assessed by magnetic resonance imaging (MRI). Relationships between proportions of immune phenotypes (of T-cells and monocytes), NP z-scores, and brain volumes were analyzed using Pearson correlations and multiple linear regression models.

RESULTS

Of N = 51 participants, 84.3% were male, 86.3% had undetectable HIV RNA < 50 copies/ml, median age was 52 [47, 57] years and median CD4 T cell count was 479 [376, 717] cells/uL. Higher CD4 T cells expressing PD-1 + and/or TIM-3 + were associated with lower executive function and working memory and higher CD8 T cells expressing PD-1+ and/or TIM-3+ were associated with reduced brain volumes in multiple regions (putamen, nucleus accumbens, cerebellar cortex, and subcortical gray matter). Furthermore, higher single or dual frequencies of PD-1 + and TIM-3 + expressing CD4 and CD8 T-cells correlated with higher CD16 + monocyte numbers.

CONCLUSIONS

This study reinforces evidence that T cells, particularly those with immune exhaustion phenotypes, are associated with neurocognitive impairment and brain atrophy in people living with HIV on ART. Relationships revealed between T-cell immune exhaustion and inflammatory in CD16+ monocytes uncover interrelated cellular processes likely involved in the immunopathogenesis of HAND.

Identification of immune subsets with distinct lectin binding signatures using multi-parameter flow cytometry: correlations with disease activity in systemic lupus erythematosus

Objectives

Cell surface glycosylation can influence protein-protein interactions with particular relevance to changes in core fucosylation and terminal sialylation. Glycans are ligands for immune regulatory lectin families like galectins (Gals) or sialic acid immunoglobulin-like lectins (Siglecs). This study delves into the glycan alterations within immune subsets of systemic lupus erythematosus (SLE).

Methods

Evaluation of binding affinities of Galectin-1, Galectin-3, Siglec-1, Aleuria aurantia lectin (AAL, recognizing core fucosylation), and Sambucus nigra agglutinin (SNA, specific for α-2,6-sialylation) was conducted on various immune subsets in peripheral blood mononuclear cells (PBMCs) from control and SLE subjects. Lectin binding was measured by multi-parameter flow cytometry in 18 manually gated subsets of T-cells, NK-cells, NKT-cells, B-cells, and monocytes in unstimulated resting state and also after 3-day activation. Stimulated pre-gated populations were subsequently clustered by FlowSOM algorithm based on lectin binding and activation markers, CD25 or HLA-DR.

Results

Elevated AAL, SNA and CD25+/CD25- SNA binding ratio in certain stimulated SLE T-cell subsets correlated with SLE Disease Activity Index 2000 (SLEDAI-2K) scores. The significantly increased frequencies of activated AALlow Siglec-1low NK metaclusters in SLE also correlated with SLEDAI-2K indices. In SLE, activated double negative NKTs displayed significantly lower core fucosylation and CD25+/CD25- Siglec-1 binding ratio, negatively correlating with disease activity. The significantly enhanced AAL binding in resting SLE plasmablasts positively correlated with SLEDAI-2K scores.

Conclusion

Alterations in the glycosylation of immune cells in SLE correlate with disease severity, which might represent potential implications in the pathogenesis of SLE.

Factors associated with insulin resistance in a longitudinal study of Ugandan youth with and without HIV

Prospective investigations from sub-Saharan Africa on metabolic complications in youth with perinatally acquired HIV (PHIV) are lacking. We investigated the changes in insulin resistance in Ugandan PHIV on ART and uninfected controls and their relationship with inflammation, HIV, and cardiovascular disease (CVD) risk factors. Participants 10-18 years of age were included in a prospective study performed in Kampala, Uganda. We compared baseline and changes in insulin resistance (by HOMA-IR) and in markers of inflammation at baseline and 96 weeks. PHIVs were on ART with HIV-1 RNA level 400 copies/ml or less. Generalized Estimating Equation models were used to assess associations between HOMA-IR, and demographic as well as inflammatory markers. Of the 197 participants recruited at baseline (101 PHIV, 96 HIV-negative), 168 (89 PHIV, 79 HIV-negative) had measurements at 96 weeks. At baseline, median (Q1, Q3) age was 13 years (11,15), 53.5% were women, median CD4 + cell counts were 988 cells/μl (631, 1310). At baseline, HOMA-IR was significantly higher in PHIV than in controls ( P  = 0.03). HOMA-IR did not significantly change by week 96 in either group, and at 96 weeks, was similar between groups ( P  = 0.15). HOMA-IR was not associated with any inflammatory markers, or any specific ART. In longitudinal analysis, age and Tanner stage remained associated with higher HOMA-IR throughout the study period, after adjusting for HIV status. In this longitudinal cohort of virally suppressed PHIV in Uganda, PHIV have decreased insulin sensitivity compared to controls, however this difference does not persist through adolescence. ART and immune activation do not appear to affect glucose homeostasis in this population.

Monocytes subsets altered distribution and dysregulated plasma hsa-miR-21-5p and hsa-miR-155-5p in HCV-linked liver cirrhosis progression to hepatocellular carcinoma

PURPOSE

The authors aim to investigate the altered monocytes subsets distribution in liver cirrhosis (LC) and subsequent hepatocellular carcinoma (HCC) in association with the expression level of plasma Homo sapiens (has)-miR-21-5p and hsa-miR-155-5p. A step toward non-protein coding (nc) RNA precision medicine based on the immune perturbation manifested as altered monocytes distribution, on top of LC and HCC.

METHODS

Seventy-nine patients diagnosed with chronic hepatitis C virus (CHCV) infection with LC were enrolled in the current study. Patients were sub-classified into LC group without HCC (n = 40), LC with HCC (n = 39), and 15 apparently healthy controls. Monocyte subsets frequencies were assessed by flow cytometry. Real-time quantitative PCR was used to measure plasma hsa-miR-21-5p and hsa-miR-155-5p expression.

RESULTS

Hsa-miR-21-5p correlated with intermediate monocytes (r = 0.30, p = 0.007), while hsa-miR-155-5p negatively correlated with non-classical monocytes (r = - 0.316, p = 0.005). ROC curve analysis revealed that combining intermediate monocytes frequency and hsa-miR-21 yielded sensitivity = 79.5%, specificity = 75%, and AUC = 0.84. In comparison, AFP yielded a lower sensitivity = 69% and 100% specificity with AUC = 0.85. Logistic regression analysis proved that up-regulation of intermediate monocytes frequency and hsa-miR-21-5p were independent risk factors for LC progression to HCC, after adjustment for co-founders.

CONCLUSION

Monocyte subsets differentiation in HCC was linked to hsa-miR-21-5p and hsa-miR-155-5p. Combined up-regulation of intermediate monocytes frequency and hsa-miR-21-5p expression could be considered a sensitive indicator of LC progression to HCC. Circulating intermediate monocytes and hsa-miR-21-5p were independent risk factors for HCC evolution, clinically and in silico proved.

Blood monocyte and dendritic cell profiles among people living with HIV with Mycobacterium tuberculosis co-infection

BACKGROUND

Understanding the complex interactions of the immune response mediated by Mycobacterium tuberculosis and HIV co-infection is fundamental to disease biomarker discovery, vaccine, and drug development. Using flow cytometry, we characterized the frequencies and phenotypic differences in monocytes and dendritic cell populations using peripheral blood mononuclear cells from individuals with recurrent, active pulmonary tuberculosis with and without coexisting HIV infection (CAPRISA 011, Clinicaltrials.gov, NCT02114684, 29/01/2014) and compared them to samples from HIV positive individuals and healthy controls. Additionally, we assessed the associations between the frequency of monocyte and dendritic cell subsets and time to culture conversion and cavitary disease in patients with active TB using a cox proportional hazards and logistic regression models.

RESULTS

Compared to healthy controls, the frequency of total monocytes (HLA-DR + CD14 +) was significantly higher in the TB/HIV and TB groups and the frequency of dendritic cells (HLA-DR + CD14-) was significantly higher in TB/HIV and HIV groups. We observed significant variation in the expression of CCR2, CD40, CD11b, CD86, CD163, CX3CR1 across different cell subsets in the four study groups. Increase in CCR2, CD11b and CD40 was associated with active TB infection, while decrease in CX3CR1 and increase in CD163 was associated with HIV infection. Expression of CX3CR1 (aHR 0.98, 95% CI 0.963 - 0.997, p = 0.019) on non-classical monocytes associated with longer time to TB culture conversion in the multivariable model correcting for randomization arm, age, sex, HIV status, lung cavitation, alcohol use, smoking and BMI. Higher surface expression of CD86 (aOR 1.017, 95% CI 1.001 - 1.032, p = 0.033) on intermediate monocytes associated with the presence of lung cavitation, while higher expression of transitional monocytes (aOR 0.944, 95% CI 0.892 - 0.999, p = 0.047) associated with the absence of lung cavitation in the multivariable model.

CONCLUSION

These data provide valuable insight into the heterogenous role of monocyte and dendritic cells in TB and HIV infections.

Optimization of monocyte gating to quantify monocyte subsets for the diagnosis of chronic myelomonocytic leukemia

BACKGROUND

The presence of >94% classical monocytes (MO1, CD14++/CD16-) in peripheral blood (PB) has an excellent performance for the diagnosis of chronic myelomonocytic leukemia (CMML). However, the monocyte gating strategy is not well defined. The objective of the study was to compare monocyte gating strategies and propose an optimal one.

METHODS

This is a prospective, single center study assessing monocyte subsets in PB. First, we compared monocyte subsets using 13 monocyte gating strategies in 10 samples. Then we developed our own 10 color tube and tested it on 124 patients (normal white blood cell counts, reactive monocytosis, CMML and a spectrum of other myeloid malignancies). Both conventional and computational (FlowSOM) analyses were used.

RESULTS

Comparing different monocyte gating strategies, small but significant differences in %MO1 and percentually large differences in %MO3 (nonclassical monocytes) were found, suggesting that the monocyte gating strategy can impact monocyte subset quantification. Then, we designed a 10-color tube for this purpose (CD45/CD33/CD14/CD16/CD64/CD86/CD300/CD2/CD66c/CD56) and applied it to 124 patients. This tube allowed proper monocyte gating even in highly abnormal PB. Computational analysis found a higher %MO1 and lower %MO3 compared to conventional analysis. However, differences between conventional and computational analysis in both MO1 and MO3 were globally consistent and only minimal differences were observed when comparing the ranking of patients according to %MO1 or %MO3 obtained with the conventional versus the computational approach.

CONCLUSIONS

The choice of monocyte gating strategy appears relevant for the monocyte subset distribution test. Our 10-color proposal allowed satisfactory monocyte gating even in highly abnormal PB. Computational analysis seems promising to increase reproducibility in monocyte subset quantification.

Cytokines in the mechanisms of regulation of monocytopoiesis in ischemic heart disease

Introduction. The relationship of the violation of the subpopulation composition of blood monocytes in ischemic cardiomyopathy (ICMP) with changes in monocytopoiesis, as well as the effect of colony-stimulating factor of macrophages (M-CSF) and cytokines on the differentiation of monocytes of various immunophenotypes in the bone marrow is of great relevance.

Aim – to study the role of cytokines in the mechanisms of local and distant regulation of differentiation of classical, intermediate, non-classical and transitional bone marrow monocytes in combination with the content of VEGFR2+-monocytes and hypoxia-induced factor-1a (HIF-1a) in the blood of patients with ischemic heart disease (IHD), suffering and not suffering from ischemic cardiomyopathy.

Materials and methods. Seventy-four patients with IHD, suffering and not suffering from ICMP (30 and 44 people, respectively) were examined. The number of subpopulations of classical (CD14++CD16–), intermediate (CD14++CD16+), nonclassical (CD14+CD16++) and transitional (CD14+CD16–) monocytes (in bone marrow samples) and CD14+VEGFR2+-monocytes (in blood and bone marrow) was determined by flow cytofluorimetry; the concentration of cytokines IL-10, IL-13, TNF-α, IFN-γ, M-CSF in bone marrow and blood, as well as HIF-1a in the blood, was determined by ELISA.

Results. Content of hematopoietins IL-10, IL-13, TNF-α, M-CSF in the bone marrow, as well as the ability of M-CSF to activate and IL-13 to inhibit the differentiation of classical monocytes from transitional cell forms were comparable between groups of patients with IHD. In the blood of patients with ICMP the concentration of IL-10 was higher, and the content of HIF-1α and CD14+VEGFR2+-cells was lower than in patients with IHD without ICMP (IL-10 – 30.00 (26.25–34.50) pg/ mL vs. 0 (23.0–28.0) pg/mL, p < 0.05; HIF-1α – 0.040 (0.029–0.053) ng/mL vs. 0.063 (0.054–0.122) ng/mL, p < 0.05; CD14+VEGFR2+ – 7.00 (5.67–7.15) % vs. 7.80 (7.23–8.17) %, p < 0.05). A feature of monocytopoiesis in ICMP compared with patients with IHD without ICMP is a high concentration of IFN-γ in the BM and a low ratio of M-CSF/IL-13 (10.00 (0.65–18.23) and 0.02 [0–0.15) pg/mL, p < 0.001; 1.02 (0.41–2.00) and 9.00 (2.13–22.09), p < 0.05, respectively), in association with a decrease in the number of classical, intermediate monocytes and an increase in the number of transitional cells in the BM in patients with ICMP relative to patients without cardiomyopathy (21.0 (19.5–23.0) and 47 (41–61.5) %, p < 0.001; 0.3 (0.0–1.2) and 18.5 (6.5–28.0) %, p < 0.01; 76.2 (73.0–78.5) and 30.5 (13.0–41.5) %, p < 0.001, respectively). At the same time, regardless of the clinical form of IHD, IL-10 and IL-13 are distant hematopoietins, TNF-α is local hematopoietin.

Conclusion. An increase in the concentration of IFN-γ and a low ratio of M-CSF/IL-13 in the bone marrow, as well as an excess of IL-10 and a lack of HIF-1a and CD14+VEGFR2+-cells in the blood of IHD patients, are associated with inhibition of differentiation of mature forms of monocytes and the development of ICMP.

Circulating brain-derived extracellular vesicles expressing neuroinflammatory markers are associated with HIV-related neurocognitive impairment

Background

Neurocognitive impairment remains prevalent in people with HIV (PWH) despite long term virological suppression by antiretroviral therapy (ART) regimens. Systemic and neuro-inflammatory processes are suggested to contribute to the complex pathology leading to cognitive impairment in this population, yet the underlying mechanisms remain unresolved. Extracellular vesicles (EVs) play a central role in intracellular communication and have emerged as key modulators of immunological and inflammatory responses. In this report, we examined the impact of EVs in PWH experiencing cognitive deficits to determine their relevance in HIV associated neuropathology.

Methods

EV phenotypes were measured in plasma samples from 108 PWH with either cognitive impairment (CI, n=92) or normal cognition (NC, n=16) by flow cytometry. Matched cerebrospinal fluid (CSF)-derived EVs were similarly profiled from a subgroup of 84 individuals who underwent a lumbar puncture. Peripheral blood mononuclear cells were assayed by flow cytometry to measure monocyte frequencies in a subset of 32 individuals.

Results

Plasma-EVs expressing CD14, CD16, CD192, C195, and GFAP were significantly higher in HIV-infected individuals with cognitive impairment compared to individuals with normal cognition. Increased CSF-EVs expressing GFAP and CD200 were found in the cognitive impairment group compared to the normal cognition group. Frequencies of patrolling monocytes correlated with plasma-EVs expressing CD14, CD66b, MCSF, MAP2, and GFAP. Frequencies of CD195 expression on monocytes correlated positively with plasma-EVs expressing CD41a, CD62P, and CD63. Expression of CD163 on monocytes correlated positively with CSF-EVs expressing GFAP and CD200. Finally, the expression of CD192 on total monocytes correlated with CSF-EVs expressing CD200, CD62P, and CD63.

Conclusions

EVs expressing monocyte activation and neuronal markers associated with HIV associated cognitive impairment, suggesting that distinct EV subsets may serve as novel biomarkers of neuronal injury in HIV infection. Further circulating platelet EV levels were linked to monocyte activation indicating a potential novel interaction in the pathogenesis of HIV-related cognitive impairment.

Characterization of Circulating Fibrocytes in People Living with HIV on Stable Antiretroviral Therapy

Highly effective combination antiretroviral therapy has reduced HIV infection to a manageable chronic disease, shifting the clinical landscape toward management of noninfectious comorbidities in people living with HIV (PLWH). These comorbidities are diverse, generally associated with accelerated aging, and present within multiple organ systems. Mechanistically, immune dysregulation and chronic inflammation, both of which persist in PLWH with well-controlled virally suppressive HIV infection, are suggested to create and exacerbate noninfectious comorbidity development. Persistent inflammation often leads to fibrosis, which is the common end point pathologic feature associated with most comorbidities. Fibrocytes are bone marrow-derived fibroblast-like cells, which emerged as key effector cells in tissue repair and pathologic fibrotic diseases. Despite their relevance to fibrosis, the circulating fibrocyte concentration in PLWH remains poorly characterized, and an understanding of their functional role in chronic HIV is limited. In this study, utilizing PBMCs from a cross-sectional adult HIV cohort study with matched uninfected controls (HIV-), we aimed to identify and compare circulating fibrocytes in blood. Both the percentage and number of fibrocytes and α-smooth muscle actin+ fibrocytes in circulation did not differ between the HIV+ and HIV- groups. However, circulating fibrocyte levels were significantly associated with increasing age in both the HIV+ and HIV- groups (the percentage and number; r = 0.575, p ≤ 0.0001 and r = 0.558, p ≤ 0.0001, respectively). Our study demonstrates that circulating fibrocyte levels and their fibroblast-like phenotype defined as collagen I and α-smooth muscle actin+ expression are comparable between, and strongly associated with, age irrespective of HIV status.

Altered adipose tissue macrophage populations in people with HIV on integrase inhibitor-containing antiretroviral therapy

OBJECTIVE

Antiretroviral therapy (ART) extends the life of people with HIV (PWH), but these individuals are at increased risk for obesity, dyslipidemia, diabetes, and cardiovascular disease. These comorbidities may be a consequence of HIV-related chronic inflammation and/or adverse effects of ART on tissue regulatory adipose tissue macrophages (ATMs). We sought to determine the effects of HIV/ART on metabolically beneficial ATM populations and functions.

DESIGN

We examined subcutaneous ATMs from PWH on integrase inhibitor-containing ART ( n  = 5) and uninfected persons ( n  = 9). We complemented these studies with ex vivo and in vitro analyses of peripheral blood mononuclear cell (PBMC) and murine macrophage lipid metabolism and fatty acid oxidation gene expression.

METHODS

ATM populations were examined by flow cytometry. Macrophage lipid metabolism and fatty acid oxidation gene expression were examined by Seahorse assay and quantitative PCR.

RESULTS

Adipose tissue from PWH had reduced populations of metabolically activated CD9 + ATMs compared to that of uninfected controls ( P  < 0.001). PBMCs of PWH had lower fatty acid metabolism compared to those of uninfected controls ( P  < 0.01). Analysis of murine macrophages revealed that dolutegravir reduced lipid metabolism ( P  < 0.001) and increased expression of the fatty acid beta-oxidation enzyme enoyl-CoA hydratase, short chain 1 ( P  < 0.05).

CONCLUSIONS

We report the loss of metabolically beneficial ATM populations in PWH on ART, altered fatty acid metabolism of blood immune cells, and evidence that dolutegravir alters macrophage fatty acid metabolism. Future studies should examine direct or indirect effects and mechanisms of dolutegravir, and other integrase inhibitors and ART classes, on fatty acid beta-oxidation.

Coronary Vasculature and Myocardial Structure in HIV: Physiologic Insights From the Renin-Angiotensin-Aldosterone System

The landscape of HIV medicine dramatically changed with the advent of contemporary antiretroviral therapies, which has allowed persons with HIV (PWH) to achieve good virologic control, essentially eliminating HIV-related complications and increasing life expectancy. As PWH are living longer, noncommunicable diseases, such as cardiovascular disease (CVD), have become a leading cause of morbidity and mortality in PWH with rates that are 50% to 100% higher than in well-matched persons without HIV. In this review, we focus on disease of the coronary microvasculature and myocardium in HIV. We highlight a key hormonal system important to cardiovascular endocrinology, the renin-angiotensin-aldosterone system (RAAS), as a potential mediator of inflammatory driven-vascular and myocardial injury and consider RAAS blockade as a physiologically targeted strategy to reduce CVD in HIV.

Galectin 3 and non-classical monocytes of blood as myocardial remodeling factors at ischemic cardiomyopathy

Aims

To identify an imbalance of cardiac remodeling mediators and monocytes subpopulation in blood, distribution of myocardium macrophages in patients with ischemic cardiomyopathy (ICMP).

Methods

The study engaged 30 patients with ICMP, 26 patients with coronary heart disease (CHD) without ICMP, 15 healthy donors. Concentrations of TGFβ, MMP-9, MCP-1, galectin-3 were measured in plasma of blood from the coronary sinus and peripheral blood in CHD patients, as well as in peripheral blood in healthy donors, by enzyme immunoassay method. The ration of classical, intermediate, non-classical, transitional monocytes in peripheral blood of patients and healthy donors was assessed by flow cytometry (expression CD14, CD16); the content of CD68+ macrophages in myocardium – by immunohistochemistry method.

Results

In both samples of blood, the content of galectin-3 in patients with ICMP was higher than in CHD patients without ICMP and the level of TGFβ was comparable between the groups. At ICMP, the concentration of MMP-9 in sinus blood was higher than that in CHD patients without ICMP in whom an excess of MCP-1 in the general blood flow was determined. The density of distribution of CD68+ cells in the myocardium in patients with ICMP was higher in the perianeurysmal zone than in the right atrium appendage. ICMP was characterized by a deficiency of non-classical monocytes, and CHD without ICMP – by an excess of intermediate cells in peripheral blood.

Conclusion

Myocardium remodeling at ICMP is mediated by not so much TGFβ but intracardiac galectin-3, which determines the subpopulation composition of blood monocytes.

Development of a 43 color panel for the characterization of conventional and unconventional T-cell subsets, B cells, NK cells, monocytes, dendritic cells, and innate lymphoid cells using spectral flow cytometry

Although many flow cytometers can analyze 30-50 parameters, it is still challenging to develop a 40+ color panel for the phenotyping of immune cells using fluorochrome conjugated antibodies due to limitations in the availability of spectrally unique fluorochromes that can be excited by the commonly used laser lines (UV, Violet, Blue, Green/Yellow-green, and Red). Spectral flowcytometry is capable of differentiating fluorochromes with significant overlap in the emission spectra, enabling the use of spectrally similar fluorochrome pairs such as Brilliant Blue 515 and FITC in a single panel. We have developed a 43 color panel to characterize most of the immune subsets within the peripheral immune system, including conventional T cells, unconventional T cells such as invariant natural killer T cells (iNKT), Gamma delta (γδ) T-cell subsets (TCR Vδ2, TCR Vγ9) and mucosal-associated invariant T cells (MAIT), B-cell subsets, natural killer (NK) cells, plasmacytoid dendritic cells, dendritic cell subsets, hematopoietic progenitor cells, basophils, and innate lymphoid cell (ILC) subsets (CD117, CRTH2). The panel includes surface markers to analyze activation (CD38, HLA-DR, ICOS/CD278), differentiation (CD45RA, CD27, CD28, CD57), expression of cytokine and chemokine receptors (CD25, CD127, CCR10, CCR6, CCR4, CXCR3, CXCR5, CRTH2/CD294), and co-inhibitory molecules and exhaustion (PD-1, CD223/LAG-3, TIGIT), which enables a deep characterization of PBMCs from peripheral blood. Cells were analyzed on a 5-laser Cytek Aurora and data analysis was done using FlowJo. This panel can help to make a thorough interpretation of immune system, specifically when specimen quantity is low. The panel has not been completely optimized but would rather act as a guide toward the development of a workflow for optimized multicolor immunophenotyping panel.

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

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

Dysfunctional Immunometabolism in HIV Infection: Contributing Factors and Implications for Age-Related Comorbid Diseases

PURPOSE OF REVIEW

An increasing body of evidence indicates that persons living with HIV (PLWH) display dysfunctional immunometabolism. Here, we provide an updated review of this topic and its relationship to HIV-associated immune stimuli and age-related disease.

RECENT FINDINGS

HIV infection alters immunometabolism by increasing reliance on aerobic glycolysis for energy and productive infection and repurposing oxidative phosphorylation machinery for immune cell proliferation and survival. Recent studies in PLWH with diabetes mellitus or cardiovascular disease have identified an association with elevated T cell and monocyte glucose metabolism, respectively. Immunometabolic dysfunction has also been observed in PLWH in frailty and additional studies suggest a role for immunometabolism in non-AIDS defining cancers and neurocognitive disease. There is a plethora of HIV-associated immune stimuli that could drive immunometabolic dysfunction and age-related disease in PLWH, but studies directly examining their relationship are lacking. Immunometabolic dysfunction is characteristic of HIV infection and is a potential link between HIV-associated stimuli and age-related comorbidities.

Increased Monocyte Inflammatory Responses to Oxidized LDL Are Associated with Insulin Resistance in HIV-Infected Individuals on Suppressive Antiretroviral Therapy

Despite long term antiretroviral therapy (ART), insulin resistance (IR) is common among people living with HIV/AIDS (PLWHA) exposing this population to a greater risk of cardiometabolic complications when compared to their uninfected counterparts. We previously identified an expansion in monocyte subpopulations in blood that were linked to the degree of IR in persons with HIV on stable ART. In this study, we directly assessed monocyte inflammatory functional properties from PLWHA on ART (n = 33) and HIV-uninfected controls (n = 14) of similar age, gender, and cardiovascular disease risk and determined the relationship with IR (homeostatic model assessment-insulin resistance (HOMA-IR)), calculated from fasting blood glucose and insulin measurements. Peripheral blood mononuclear cells were stimulated with oxidized low-density lipoproteins (oxLDL) and polyfunctional monocyte cytokine responses (IL-1β, IL-6, IL-8, or TNF-α) were determined by flow cytometry. Higher monocyte IL-1β and IL-8 responses to oxLDL were associated with higher IR in PLWHA but not in the control group. We observed that higher basal monocyte cytokine responses were associated with both duration since HIV diagnosis and ART initiation. In the management of IR in chronic HIV, strategies lowering monocyte IL-1β and IL-8 responses should be considered in addition to ART in order to limit adverse cardio-metabolic outcomes.

T Lymphocyte Subsets Associated With Prevalent Diabetes in Veterans With and Without Human Immunodeficiency Virus

BACKGROUND

A higher proportion of circulating memory CD4+ T cells is associated with prevalent diabetes mellitus in the general population. Given the broad changes in adaptive immunity, including memory T-cell expansion, and rising prevalence of diabetes in the human immunodeficiency virus (HIV) population, we assessed whether similar relationships were present in persons with HIV (PWH).

METHODS

Multiple CD4+ and CD8+ T-cell subsets were measured by flow cytometry, and prevalent diabetes cases were adjudicated by 2 physicians for PWH and HIV-negative participants in the Veterans Aging Cohort Study. Multivariable logistic regression models evaluated the association of T-cell subsets and diabetes stratified by HIV status, adjusted for cytomegalovirus serostatus and traditional risk factors.

RESULTS

Among 2385 participants (65% PWH, 95% male, 68% African American), higher CD45RO+ memory CD4+ T cells and lower CD38+ CD4+ T cells were associated with prevalent diabetes, and had a similar effect size, in both the PWH and HIV-negative (P ≤ .05 for all). Lower CD38+CD8+ T cells were also associated with diabetes in both groups.

CONCLUSIONS

The CD4+ and CD8+ T-cell subsets associated with diabetes are similar in PWH and HIV-negative individuals, suggesting that diabetes in PWH may be related to chronic immune activation.

Lower Interferon Regulatory Factor-8 Expression in Peripheral Myeloid Cells Tracks With Adverse Central Nervous System Outcomes in Treated HIV Infection

Cognitive dysfunction persists in 30–50% of chronically HIV-infected individuals despite combination antiretroviral therapy (ART). Although monocytes are implicated in poor cognitive performance, distinct biological mechanisms associated with cognitive dysfunction in HIV infection are unclear. We previously showed that a regulatory region of the interferon regulatory factor-8 (IRF8) gene is hyper-methylated in HIV-infected individuals with cognitive impairment compared to those with normal cognition. Here, we investigated IRF-8 protein expression and assessed relationships with multiple parameters associated with brain health. Intracellular IRF-8 expression was measured in cryopreserved peripheral blood mononuclear cells from chronically HIV-infected individuals on ART using flow cytometry. Neuropsychological performance was assessed by generating domain-specific standardized (NPZ) scores, with a global score defined by aggregating individual domain scores. Regional brain volumes were obtained by magnetic resonance imaging and soluble inflammatory factors were assessed by immunosorbent assays. Non-parametric analyses were conducted and statistical significance was defined as p < 0.05. Twenty aviremic (HIV RNA<50 copies/ml) participants, 84% male, median age 51 [interquartile range (IQR) 46, 55], median CD4 count 548 [439, 700] were evaluated. IRF-8 expression was highest in plasmacytoid dendritic cells (pDCs). Assessing cognitive function, lower IRF-8 density in classical monocytes significantly correlated with worse NPZ_learning memory (LM; rho = 0.556) and NPZ_working memory (WM; rho = 0.612) scores, in intermediate monocytes with worse NPZ_LM (rho = 0.532) scores, and in non-classical monocytes, lower IRF-8 correlated with worse global NPZ (rho = 0.646), NPZ_LM (rho = 0.536), NPZ_WM (rho = 0.647), and NPZ_executive function (rho = 0.605) scores. In myeloid DCs (mDCs) lower IRF-8 correlated with worse NPZ_WM (rho = 0.48) scores and in pDCs with worse NPZ_WM (rho = 0.561) scores. Declines in IRF-8 in classical monocytes significantly correlated with smaller hippocampal volume (rho = 0.573) and in intermediate and non-classical monocytes with smaller cerebral white matter volume (rho = 0.509 and rho = 0.473, respectively). IRF-8 density in DCs did not significantly correlate with brain volumes. Among biomarkers tested, higher soluble ICAM-1 levels significantly correlated with higher IRF-8 in all monocyte and DC subsets. These data may implicate IRF-8 as a novel transcription factor in the neuropathophysiology of brain abnormalities in treated HIV and serve as a potential therapeutic target to decrease the burden of cognitive dysfunction in this population.

Relationship between Circulating Inflammatory Monocytes and Cardiovascular Disease Measures of Carotid Intimal Thickness

Aims: Cardiovascular disease (CVD) remains the leading cause of death worldwide despite improvements in the treatment of atherosclerosis, an inflammatory disease and major underlying cause of CVD. Monocytes, an innate immune cell type, are linked to CVD progression; however, given their heterogeneity, the association between distinct monocyte subsets and increased risk of CVD remains unclear. This study investigated the association between peripheral monocyte subpopulation numbers and carotid intima-media thickness (cIMT), a sensitive measure of CVD risk, in a cohort of adults recruited from the general population.

Methods: We used clinical data and peripheral blood mononuclear cell (PBMC) specimens from 67 individuals. cIMT was measured by high-resolution, B-mode, ultrasound images of the right carotid artery. PBMCs were stained with conjugated monoclonal antibodies to define monocyte subpopulations based on CD14 and CD16 co-expressions into classical (CD14⁺⁺CD16⁻), intermediate/inflammatory (CD14⁺⁺CD16⁺), and non-classical/patrolling (CD14^low/+CD16⁺⁺) monocytes.

Results: We found a higher intermediate monocyte count was significantly correlated with increased right common carotid artery (RCCA) and right carotid bifurcation (RBIF) intima-media thickness (IMT) (p = 0.004 and 0.006, respectively), even after adjusting for CVD-associated clinical data (p = 0.006 and 0.004, respectively).

Conclusion: Our study demonstrated a strong correlation between inflammatory monocyte counts and cIMT. These results suggest that, in the general population, there is a relationship between intermediate monocyte expansion and elevated predictors for CVD risk, and intermediate monocytes may be involved in the development of atherosclerosis and metabolic diseases. Strategies targeting inflammatory monocytes may be needed to slow CVD progression.

Comparative DNA methylomic analyses reveal potential origins of novel epigenetic biomarkers of insulin resistance in monocytes from virally suppressed HIV-infected adults

BACKGROUND

Compared to healthy individuals, those with stably repressed HIV experience a higher risk of developing insulin resistance, a hallmark of pre-diabetes and a major determinant for cardiometabolic diseases. Although epigenetic processes, including in particular DNA methylation, appear to be dysregulated in individuals with insulin resistance, little is known about where these occur in the genomes of immune cells and the origins of these alterations in HIV-infected individuals. Here, we examined the genome-wide DNA methylation states of monocytes in HIV-infected individuals (n = 37) with varying levels of insulin sensitivity measured by the homeostatic model assessment of insulin resistance (HOMA-IR).

RESULTS

By profiling DNA methylation at single-nucleotide resolution using the Illumina Infinium HumanMethylation450 BeadChip in monocytes from insulin-resistant (IR; HOMA-IR ≥ 2.0; n = 14) and insulin-sensitive (IS; HOMA-IR < 2.0; n = 23) individuals, we identified 123 CpGs with significantly different DNA methylation levels. These CpGs were enriched at genes involved in pathways relating to glucose metabolism, immune activation, and insulin-relevant signaling, with the majority (86.2%) being hypomethylated in IR relative to IS individuals. Using a stepwise multiple logistic regression analysis, we observed 4 CpGs (cg27655935, cg02000426, cg10184328, and cg23085143) whose methylation levels independently predicted the insulin-resistant state at a higher confidence than that of clinical risk factors typically associated with insulin resistance (i.e., fasting glucose, 120-min oral glucose tolerance test, Framingham Risk Score, and Total to HDL cholesterol ratio). Interestingly, 79 of the 123 CpGs (64%) exhibited remarkably similar levels of methylation as that of hematopoietic stem cells (HSC) in monocytes from IR individuals, implicating epigenetic defects in myeloid differentiation as a possible origin for the methylation landscape underlying the insulin resistance phenotype. In support of this, gene ontology analysis of these 79 CpGs revealed overrepresentation of these CpGs at genes relevant to HSC function, including involvement in stem cell pluripotency, differentiation, and Wnt signaling pathways.

CONCLUSION

Altogether, our data suggests a possible role for DNA methylation in regulating monocyte activity that may associate with the insulin-resistant phenotype. The methylomic landscape of insulin resistance in monocytes could originate from epigenetic dysregulation during HSC differentiation through the myeloid lineage. Understanding the factors involved with changes in the myeloid trajectory may provide further insight into the development of insulin resistance. Furthermore, regulation of specific genes that were implicated in our analysis reveal possible targets for modulating immune activity to ameliorate insulin resistance.

Inflammation and Metabolic Complications in HIV

PURPOSE OF REVIEW

We aim to provide an in-depth review of recent literature highlighting the role of inflammation involving the adipose tissue, liver, skeletal muscles, and gastrointestinal tract in the development of metabolic complications among persons living with HIV (PLWH).

RECENT FINDINGS

Recent studies in PLWH have demonstrated a significant association between circulating inflammatory markers and development of insulin resistance and metabolic complications. In adipose tissue, pro-inflammatory cytokine expression inhibits adipocyte insulin signaling, which alters lipid and glucose homeostasis. Increased lipolysis and lipogenesis elevate levels of circulating free fatty acids and promote ectopic fat deposition in liver and skeletal muscles. This leads to lipotoxicity characterized by a pro-inflammatory response with worsening insulin resistance. Finally, HIV is associated with gastrointestinal tract inflammation and changes in the gut microbiome resulting in reduced diversity, which is an additional risk factor for diabetes. Metabolic complications in PLWH are in part due to chronic, multisite tissue inflammation resulting in dysregulation of glucose and lipid trafficking, utilization, and storage.

Factors Associated With Insulin Resistance in Adults With HIV Receiving Contemporary Antiretroviral Therapy: a Brief Update

PURPOSE OF REVIEW

This narrative review summarizes recent data on factors associated with insulin resistance (IR) in adults with HIV, including contemporary antiretroviral therapy (ART).

RECENT FINDINGS

IR remains common in persons with HIV, even those receiving contemporary ART. Generalized and abdominal obesity and ectopic fat are correlates of IR, and emerging data have identified associations with biomarkers of inflammation and immune activation. Small studies suggest associations between mitochondria and IR. In ART-naïve individuals, IR increased within 4 weeks of starting ART in persons receiving contemporary boosted protease inhibitors or an integrase inhibitor. The importance of IR in non-diabetic persons with HIV will continue to grow as the population ages and obesity increases. Non-invasive estimates of IR appear to perform well in persons with HIV, but clinically relevant cutoffs are uncertain. Unexpected metabolic effects of newer HIV integrase inhibitors have been reported; thus, careful observation for and studies of IR are still warranted.

Acute hyperinsulinemia effects on systemic markers of immune activation in HIV

: The well treated HIV population remains at risk for insulin resistance and chronic immune activation. We tested the effects of acute hyperinsulinemia on inflammation in HIV. Twenty HIV-infected and 10 non-HIV-infected individuals well matched for BMI underwent oral glucose tolerance testing to stimulate insulin secretion and assess for changes in circulating soluble CD163, soluble CD14, and monocyte chemoattract protein 1. Soluble CD14 decreased significantly after stimulation of hyperinsulinemia and no significant changes in soluble CD163 or monocyte chemoattract protein 1 were demonstrated in HIV-infected and non-HIV-infected groups.

Plasminogen Activator Inhibitor-1 Predicts Negative Alterations in Whole-Body Insulin Sensitivity in Chronic HIV Infection

Plasminogen activator inhibitor type 1 (PAI-1), a key negative regulator of fibrinolysis, has been investigated to be one of the potential mechanisms of the development of impaired insulin sensitivity, insulin resistance, and diabetes mellitus. Because chronically stable HIV-infected individuals frequently develop abnormal glucose metabolism, including insulin resistance and diabetes mellitus, we postulated that PAI-1 could be one of the multifactorial pathogenic roles in the development of impaired insulin sensitivity and insulin resistance among chronic HIV-infected individuals. From our longitudinal cohort study, we selectively recruited chronically stable HIV-infected individuals without diagnosis of diabetes mellitus at baseline (N = 62) to analyze the correlation of baseline inflammatory cytokines, including PAI-1 and whole-body insulin sensitivity, with 2-year follow-up, as measured by Matsuda Index. We found a negative correlation between baseline PAI-1 and Matsuda Index (r = -0.435, p = .001) and a negative correlation between baseline PAI-1 and Matsuda Index at 2 years (r = -0.377, p = .005). In a linear regression model that included age, total body fat mass percentage, serum amyloid A, and family history of diabetes mellitus, PAI-1 still remained significantly associated with Matsuda Index at 2-year follow-up (β = -.397, p = .002). Our longitudinal study suggests that PAI-1 is an independent predictor of impaired insulin sensitivity among chronic HIV-infected individuals.

Antiretroviral Therapy-induced Insulin Resistance and Oxidative Deoxy Nucleic Acid Damage in Human Immunodeficiency Virus-1 Patients

BACKGROUND AND OBJECTIVES

Insulin resistance (IR) is frequent in human immunodeficiency virus (HIV) infection and may be related to antiretroviral therapy (ART). Increased oxidative stress parameters and carbonyl protein are linked to insulin sensitivity. The present study is aimed to determine IR, its association with oxidative deoxy nucleic acid (DNA) damage in HIV-1-infected patients with different ART status.

MATERIALS AND METHODS

In this case-control study, a total 600 subjects were included. We used plasma levels of the oxidized base, 8-hydroxy-2-deoxyguanosine (8-OHdG), as our biomarker of oxidative DNA damage. 8-OHdG was measured with the highly sensitive 8-OHdG check enzyme-linked immunosorbent assay kit. IR was determined using homeostasis model assessment.

RESULTS

All subjects were randomly selected and grouped as HIV-negative (control group) (n = 300), HIV-positive without ART (n = 100), HIV-positive with ART first line (n = 100), and HIV-positive with ART second line (n = 100). IR and oxidative DNA damage were significantly higher in HIV-positive patients with second-line ART and HIV-positive patients with first-line ART than ART-naive patients. In a linear regression analysis, increased IR was positively associated with the increased DNA damage (odds ratio: 3.052, 95% confidence interval: 2.595-3.509) P < 0.001.

INTERPRETATION AND CONCLUSIONS

In this study, we observed that ART plays a significant role in the development of IR and oxidative DNA damage in HIV-positive patients taking ART. Awareness and knowledge of these biomarkers may prove helpful to clinicians while prescribing ART to HIV/AIDS patients. Larger studies are warranted to determine the exact role of ART in the induction of IR and DNA damage.

Effects of Sodium Restriction on Activation of the Renin-Angiotensin-Aldosterone System and Immune Indices During HIV Infection

BACKGROUND

 Human immunodeficiency virus (HIV)-infected patients demonstrate increased activation of the renin-angiotensin-aldosterone system (RAAS). We evaluated changes in immune markers with physiological RAAS activation.

METHODS

 Immune activation markers were assessed serially in 18 HIV-infected and 7 non-HIV-infected subjects consuming an ad libitum diet followed by a standardized low-sodium diet.

RESULTS

 Levels of CCL-2 (P = .0004) and soluble CD163 (P = .0001) significantly increased with sodium restriction and RAAS activation, compared with levels in individuals with ad libitum sodium intake, among chronically treated HIV-infected subjects (mean duration of ART [±SEM], 11 ± 1 years), but not among non-HIV-infected subjects of similar age and sex.

CONCLUSIONS

 Dietary sodium restriction, which activates RAAS, uniquely stimulates critical indices of immune activation during HIV infection.

CLINICAL TRIALS REGISTRATION

 NCT01407237.

Short Communication: Do Cytomegalovirus Antibody Levels Associate with Age-Related Syndromes in HIV Patients Stable on Antiretroviral Therapy?

HIV(+) persons stable on antiretroviral therapy (ART) face early onset of age-related diseases. This may arise from a high burden of cytomegalovirus (CMV). To address the role of CMV, we investigated univariate and multivariate associations between markers of systemic and endothelial inflammation, vascular damage, insulin resistance (IR), neurocognitive decline, and antibodies reactive with CMV. In this study, HIV(+) participants (n = 91) aged >45 years with <50 copies HIV RNA/ml plasma after >2 years on ART were assessed for cardiovascular risk (the D:A:D algorithm), type II diabetes (the HOMA-IR index), and neurocognitive performance. Blood samples were assayed for lipids, T cells, insulin, glucose, C-reactive protein, CX3CL1, sTNF-R1, total immunoglobulin G (IgG), and antibodies reactive with CMV lysate, glycoprotein B, or immediate-early-1. Levels of antibodies detected with the three antigens were tightly correlated. Levels of CMV lysate antibody were higher in patients than in age-matched healthy controls and reflected their nadir CD4 T-cell count (p = .001), total IgG (p = .02), and age (p = .08). Levels of CMV lysate antibody correlated with D:A:D score (p = .04), neurocognitive performance (p = .045), and fasting insulin (p = .02). In multivariable analyses, some associations reflected the effect of age, but CMV lysate antibody and CD8 T-cell counts were significant predictors of the HOMA-IR index (R(2) = 0.09, p = .01) independent of age. We conclude that associations between levels of CMV antibodies, cardiovascular risk, and neurocognitive health in HIV(+) patients stable on ART are moderated by age-associated increases in response to CMV, while CMV antibodies may be independently linked with IR.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

DESIGN AND METHODS

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

RESULTS

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

CONCLUSION

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

Systemic and cell-specific mechanisms of vasculopathy induced by human immunodeficiency virus and highly active antiretroviral therapy

OBJECTIVE

Patients infected with human immunodeficiency virus (HIV) have higher rates of dyslipidemia, atherosclerosis, and chronic inflammation that can damage the vascular system compared with the general population. This can be attributed both to HIV itself and to highly active antiretroviral therapy (HAART) they receive. This review outlines the mechanisms by which HIV and HIV medications can cause vascular complications and identifies strategic areas of research to treat these dysfunctions.

REVIEW

HIV and HAART affect the vascular system through several mechanisms that target systemic or metabolic systems and specific cells. HIV causes dyslipidemia and chronic immune activation, which can contribute to atherosclerosis. In addition, HIV damages macrophages, endothelial cells, smooth muscle cells, and platelets, and this damage also plays a role in the development of atherosclerosis. HAART, particularly protease inhibitors, interferes with cholesterol metabolism and can affect macrophages, endothelial cells, and smooth muscle cells. The metabolic changes and cell damage induced by HIV and HAART put HIV patients at increased risk for atherosclerosis, dyslipidemia, and serious cardiovascular events such as myocardial infarction and stroke.

CONCLUSIONS

HIV patients have increased risk of developing potentially life-threatening cardiovascular pathology, which cannot be explained by traditional cardiovascular risk factors alone. More research is needed into therapies to target this HIV-specific vasculopathy.

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

BACKGROUND

Persistent inflammation and immune activation has been hypothesized to contribute to increased prevalence of subclinical atherosclerosis and cardiovascular disease (CVD) risk in patients with chronic HIV infection. In this study, we examined the correlation of peripheral monocyte subsets and soluble biomarkers of inflammation to coronary artery calcium (CAC) progression, as measured by cardiac computed tomography scan.

METHODS

We conducted a longitudinal analysis utilizing baseline data of 78 participants with HIV infection on stable antiretroviral therapy (ART) in the Hawaii Aging with HIV-Cardiovascular study who had available baseline monocyte subset analysis as well as CAC measurement at baseline and at 2-year follow up. Monocyte phenotypes were assessed from cryopreserved blood by flow cytometry and plasma was assayed for soluble biomarkers using antibody-coated beads in a high sensitivity Milliplex Luminex platform. Change in CAC over 2 years was analyzed as the primary outcome variable.

RESULTS

Of all monocyte subsets and biomarkers tested, higher non-classical monocyte percentage (ρ = 0.259, p = 0.022), interleukin (IL)-6 (ρ = 0.311, p = 0.012), and monocyte chemoattractant protein (MCP)-1 (ρ = 0.524, p = <0.001) were significantly correlated to higher 2-year CAC progression in unadjusted Spearman's correlation. Non-classical monocyte percentage (ρ = 0.247, p = 0.039), and MCP-1 (ρ = 0.487, p = <0.001), remained significantly correlated to 2-year CAC progression, while IL-6 was not (ρ = 0.209, p = 0.120) after adjustment for age, hypertension, diabetes mellitus, total/HDL cholesterol ratio, smoking history, and BMI.

CONCLUSION

The percentage of non-classical monocytes and plasma MCP-1 levels were independently associated with CAC progression and may be related to the progression of atherosclerosis and increased CVD risk associated with chronic HIV infection on stable ART.

Loss of intraepidermal nerve fiber density during SIV peripheral neuropathy is mediated by monocyte activation and elevated monocyte chemotactic proteins

Background

Peripheral neuropathy (PN) continues to be a major complication of human immunodeficiency virus (HIV) infection despite successful anti-retroviral therapy. Human HIV-PN can be recapitulated in a CD8-depleted, simian immunodeficiency virus (SIV)-infected rhesus macaque animal model, characterized by a loss of intraepidermal nerve fiber density (IENFD) and damage to the dorsal root ganglia (DRG). Increased monocyte traffic to the DRG has previously been associated with severe DRG pathology, as well as a loss in IENFD. Here, we sought to characterize the molecular signals associated with monocyte activation and trafficking to the DRGs.

Methods

Eleven SIV-infected CD8-depleted rhesus macaques were compared to four uninfected control animals. sCD14, sCD163, sCD137, regulated on activation normal T cell expressed and secreted (RANTES), and monocyte chemoattractant protein 1 (MCP-1) were measured in plasma and the latter three proteins were also quantified in DRG tissue lysates. All SIV-infected animals received serial skin biopsies to measure IENFD loss as well as BrdU inoculations to measure monocyte turnover during the course of infection. The number of BrdU+ and CD14+ CD16+ peripheral blood monocytes was determined by flow cytometry. The number of MAC387+, CCR2+, CCR5+, and CD137+ cells in DRG tissue was quantified by immunohistochemistry.

Results

sCD14, sCD163, MCP-1, and sCD137 increased significantly in plasma from pre-infection to necropsy. Plasma sCD163 and RANTES inversely correlated with IENFD. Additionally, sCD137 in DRG tissue lysate was elevated with severe DRG pathology and associated with the recruitment of MAC387+ cells to DRG. Elevated numbers of CCR5+ and CCR2+ satellite cells in the DRG were found, suggesting a chemotactic role of their ligands, RANTES, and MCP-1 in recruiting monocytes to the tissue.

Conclusions

We characterized the role of systemic (plasma) and tissue-specific (DRG) monocyte activation and associated cytokines in the pathogenesis of SIV-PN. We identified sCD163 and RANTES as potential biomarkers for HIV-PN, as these were associated with a loss of IENFD. Additionally, we identified CD137 signaling to play a role in MAC387+ cell traffic to DRG and possibly contribute to severe pathology. These studies highlight the role of monocyte activation and traffic in the pathogenesis of SIV-PN, while identifying specific signaling proteins for future pharmacological blockade.

Risk factors for the development of glucocorticoid-induced diabetes mellitus

AIMS

To evaluate the incidence of glucocorticoid-induced diabetes mellitus (GC-DM) by repeated measurements of the postprandial glucose and detect predictors for the development of GC-DM.

METHODS

Inpatients with rheumatic or renal disease who received glucocorticoid therapy were enrolled in this study. We compared the clinical and laboratory parameters of the GC-DM group with the non-GC-DM group and performed a multivariate analysis to identify risk factors.

RESULTS

During a four-week period, 84 of the 128 patients (65.6%) developed GC-DM. All patients were diagnosed based on the detection of postprandial hyperglycemia. The GC-DM group had an older age (65.2 vs. 50.4 years, p<0.0001), higher levels of fasting plasma glucose (93.3 vs. 89.0mg/dl, p=0.027) and HbA1c (5.78 vs. 5.50%, 39.7 vs. 36.6 mmol/mol, p=0.001) and lower eGFR values (54.0 vs. 77.1 ml/min/1.73 m(2), p=0.0003) than the non-GC-DM group. According to the multivariate analysis, an older age (more than or equal to 65 years), higher HbA1c level (more than or equal to 6.0%) and lower eGFR (<40 ml/min/1.73m(2)) were identified as independent risk factors for GC-DM (OR 2.95, 95% CI 1.15-7.92, OR: 3.05, 95% CI 1.11-9.21, OR: 3.42, 95% CI: 1.22-10.8, respectively). The risk ratio for the development of GC-DM in the patients with at least one of these three risk factors was 2.28. The dose of glucocorticoids was not statistically related to the development of GC-DM.

CONCLUSIONS

Patients with an older age, higher HbA1c level and lower eGFR require close monitoring for the development of GC-DM, regardless of the dose of glucocorticoids being administered.

Modulation of monocyte subsets in infectious diseases

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

Treatment intensification with maraviroc (CCR5 antagonist) leads to declines in CD16-expressing monocytes in cART-suppressed chronic HIV-infected subjects and is associated with improvements in neurocognitive test performance: implications for HIV-associated neurocognitive disease (HAND)

HIV-associated neurocognitive disorders (HAND) continues to be prevalent (30-50%) despite plasma HIV-RNA suppression with combination antiretroviral therapy (cART). There is no proven therapy for individuals on suppressive cART with HAND. We have shown that the degree of HIV reservoir burden (HIV DNA) in monocytes appear to be linked to cognitive outcomes. HIV infection of monocytes may therefore be critical in the pathogenesis of HAND. A single arm, open-labeled trial was conducted to examine the effect of maraviroc (MVC) intensification on monocyte inflammation and neuropsychological (NP) performance in 15 HIV subjects on stable 6-month cART with undetectable plasma HIV RNA (<48 copies/ml) and detectable monocyte HIV DNA (>10 copies/10(6) cells). MVC was added to their existing cART regimen for 24 weeks. Post-intensification change in monocytes was assessed using multiparametric flow cytometry, monocyte HIV DNA content by PCR, soluble CD163 (sCD163) by an ELISA, and NP performance over 24 weeks. In 12 evaluable subjects, MVC intensification resulted in a decreased proportion of circulating intermediate (median; 3.06% (1.93, 6.45) to 1.05% (0.77, 2.26)) and nonclassical (5.2% (3.8, 7.9) to 3.2% (1.8, 4.8)) CD16-expressing monocytes, a reduction in monocyte HIV DNA content to zero log10 copies/10(6) cells and in levels of sCD163 of 43% by 24 weeks. This was associated with significant improvement in NP performance among six subjects who entered the study with evidence of mild to moderate cognitive impairment. The results of this study suggest that antiretroviral therapy with potency against monocytes may have efficacy against HAND.