Human Immunodeficiency Virus Is Associated With Higher Levels of Systemic Inflammation Among Kenyan Adults Despite Viral Suppression

Dopamine-driven Increase in IL-1β in Myeloid Cells is Mediated by Differential Dopamine Receptor Expression and Exacerbated by HIV

The catecholamine neurotransmitter dopamine is classically known for regulation of central nervous system (CNS) functions such as reward, movement, and cognition. Increasing evidence also indicates that dopamine regulates critical functions in peripheral organs and is an important immunoregulatory factor. We have previously shown that dopamine increases NF-κB activity, inflammasome activation, and the production of inflammatory cytokines such as IL-1β in human macrophages. As myeloid lineage cells are central to the initiation and resolution of acute inflammatory responses, dopamine-mediated dysregulation of these functions could both impair the innate immune response and exacerbate chronic inflammation. However, the exact pathways by which dopamine drives myeloid inflammation are not well defined, and studies in both rodent and human systems indicate that dopamine can impact the production of inflammatory mediators through both D1-like dopamine receptors (DRD1, DRD5) and D2-like dopamine receptors (DRD2, DRD3, and DRD4). Therefore, we hypothesized that dopamine-mediated production of IL-1β in myeloid cells is regulated by the ratio of different dopamine receptors that are activated. Our data in primary human monocyte-derived macrophages (hMDM) indicate that DRD1 expression is necessary for dopamine-mediated increases in IL-1β, and that changes in the expression of DRD2 and other dopamine receptors can alter the magnitude of the dopamine-mediated increase in IL-1β. Mature hMDM have a high D1-like to D2-like receptor ratio, which is different relative to monocytes and peripheral blood mononuclear cells (PBMCs). We further confirm in human microglia cell lines that a high ratio of D1-like to D2-like receptors promotes dopamine-induced increases in IL-1β gene and protein expression using pharmacological inhibition or overexpression of dopamine receptors. RNA-sequencing of dopamine-treated microglia shows that genes encoding functions in IL-1β signaling pathways, microglia activation, and neurotransmission increased with dopamine treatment. Finally, using HIV as an example of a chronic inflammatory disease that is substantively worsened by comorbid substance use disorders (SUDs) that impact dopaminergic signaling, we show increased effects of dopamine on inflammasome activation and IL-1β in the presence of HIV in both human macrophages and microglia. These data suggest that use of addictive substances and dopamine-modulating therapeutics could dysregulate the innate inflammatory response and exacerbate chronic neuroimmunological conditions like HIV. Thus, a detailed understanding of dopamine-mediated changes in inflammation, in particular pathways regulating IL-1β, will be critical to effectively tailor medication regimens.

Accelerated aging in people living with HIV: The neuroimmune feedback model

People living with HIV (PLWH) experience earlier onset of aging-related comorbidities compared to their counterparts without HIV. This paper lays out a theoretical model to explain why PLWH experience accelerated aging. Briefly, the model is structured as follows. PLWH experience disproportionately heavy burdens of psychosocial stress across the life course. This psychosocial stress increases risks for depressive symptoms and problematic substance use. Depressive symptoms and problematic substance use interfere with long-term adherence to antiretroviral therapy (ART). Lower ART adherence, in turn, exacerbates the elevated systemic inflammation stemming from HIV infection. This inflammation increases risks for aging-related comorbidities. Systemic inflammation also reduces connectivity in the brain's central executive network (CEN), a large-scale brain network that is critical for coping with stressful circumstances. This reduced capacity for coping with stress leads to further increases in depressive symptoms and problematic substance use. Together, these changes form a neuroimmune feedback loop that amplifies the impact of psychosocial stress on aging-related comorbidities. In this paper, I review the existing evidence relevant to this model and highlight directions for future research.

Multi-modal analysis of inflammation as a potential mediator of depressive symptoms in young people with HIV: The GOLD depression study

People living with HIV are at three times greater risk for depressive symptoms. Inflammation is a notable predictor of depression, and people with HIV exhibit chronic inflammation despite antiretroviral therapy. We hypothesised that inflammatory biomarkers may mediate the association between HIV status and depressive symptoms. Participants (N = 60, 53% girls, median [interquartile range (IQR)] age 15.5 [15.0, 16.0] years, 70% living with HIV, of whom 90.5% were virally-suppressed) completed the nine-item Patient Health Questionnaire (PHQ-9). We measured choline and myo-inositol in basal ganglia, midfrontal gray matter, and peritrigonal white matter using magnetic resonance spectroscopy, and 16 inflammatory proteins in blood serum using ELISA and Luminex™ multiplex immunoassays. Using structural equation mediation modelling, we calculated standardised indirect effect estimates with 95% confidence intervals. Median [IQR] total PHQ-9 score was 3 [0, 7]. HIV status was significantly associated with total PHQ-9 score (B = 3.32, p = 0.022). Participants with HIV showed a higher choline-to-creatine ratio in the basal ganglia than those without HIV (β = 0.86, pFDR = 0.035). In blood serum, participants with HIV showed higher monocyte chemoattractant protein-1 (MCP-1, β = 0.59, pFDR = 0.040), higher chitinase-3 like-1 (YKL-40, β = 0.73, pFDR = 0.032), and lower interleukin-1beta (IL-1β, β = -0.67, pFDR = 0.047) than those without HIV. There were no significant associations of any biomarkers with total PHQ-9 score. None of the indirect effects were significant, mediating <13.1% of the association. Findings remained consistent when accounting for age, gender, and time between neuroimaging and PHQ-9 administration. Using a robust analytical approach in a community-based sample, we have shown that participants living with HIV reported greater depressive symptoms than those without HIV, but we did not find that neuroimaging and blood biomarkers of inflammation significantly mediated this association. Further studies with participants experiencing severe depression may help to elucidate the links between HIV, inflammation, and depression.

Impact of steatotic liver disease and non-alcoholic steatohepatitis on cognitive impairment in people living with HIV: A cross-sectional study

INTRODUCTION

The link between fatty liver diseases and cognitive impairment among people living with HIV (PLWH) remains unclear. We investigated the association of steatotic liver disease (SLD), advanced liver fibrosis and non-alcoholic steatohepatitis (NASH) with significant activity and liver fibrosis with cognitive impairment in PLWH.

METHODS

Cognitive performance was assessed for PLWH aged ≥50 years on stable antiretroviral therapy (ART) with the Thai-validated version of the Montreal Cognitive Assessment (MoCA), and a cut-off of <25/30 was used to define cognitive impairment. SLD and NASH with significant activity and liver fibrosis were defined as having a controlled attenuation parameter value ≥248 dB/m and a FibroScan-AST (FAST) score ≥0.67, respectively. Multivariable logistic regression was employed to investigate the association of cognitive impairment with SLD or NASH.

RESULTS

Of the 319 PLWH (63.3% male and 98% had HIV-1 RNA ≤50 copies/mL) included, 74 (38%) had SLD. NASH with significant activity and liver fibrosis was present in 66 (20.1%) participants. Some 192 (60.2%) participants had cognitive impairment. In a multivariable analysis, NASH with significant activity and liver fibrosis was significantly associated with cognitive impairment (adjusted odds ratio [aOR] 2.01, 95% CI 1.02-3.98, p = 0.04), after adjusting for HIV-related parameters, age, sex, body mass index, employment status, education, income level, smoking, alcohol use, diabetes mellitus, hypertension and HIV-related parameters. The association of a lone diagnosis of SLD and cognitive impairment was not statistically significant.

CONCLUSIONS

NASH with significant activity and liver fibrosis was associated with lower cognitive performance, even after controlling for demographics and HIV disease parameters. Additional research is needed to better understand the underlying mechanisms.

Latent tuberculosis is associated with heightened levels of pro-and anti-inflammatory cytokines among Kenyan men and women living with HIV on long-term antiretroviral therapy

BACKGROUND

Persons with HIV (PWH) on antiretroviral therapy (ART) have persistent immune activation associated with increased risk for non-AIDS related diseases. Latent tuberculosis infection (LTBI), endemic in Africa, may contribute to this immune dysregulation. We evaluated the impact of HIV and TB co-infection on plasma pro- and anti-inflammatory cytokines among Kenyan adults.

METHODS

We compared data from 221 PWH on long-term ART and 177 HIV-negative adults examining biomarkers of pro-[sCD14, interleukin (IL)-2, IL-6, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-12p70, IL-17A] and anti(IL-4, IL-5, IL-13) inflammatory cytokines, by HIV/LTBI status (HIV+LTBI+, HIV+LTBI-, HIV-LTBI+, HIV-LTBI-). LTBI was diagnosed based on a positive QuantiFERON TB Gold-Plus test in the absence of active TB symptoms. Linear regression was used to evaluate the associations of HIV, LTBI, and HIV/LTBI status with biomarkers adjusting for clinical factors including HIV-specific factors.

RESULTS

Half of the participants were women and 52% had LTBI. HIV was independently associated with higher sCD14, IL-15, IL-6, IL-4, IL-5. LTBI was independently associated with higher TNF-α, IL-12p70, IL-17A, IL-4, IL-13 in adjusted models ( P  < 0.05). LTBI status was associated with higher IL-4 and IL-12p70 only among PWH, but not HIV-negative participants ( P  < 0.05 for interactions). In multivariate analysis, only HIV+LTBI+ demonstrated elevated levels of TNF-α, IL-6, IL-12p70, IL-15, IL-17A, IL4, IL-5, IL-13 in comparison to the HIV-LTBI- ( P  < 0.05 for all). The effect of LTBI on cytokines among PWH was independent of CD4 + T-cell count and ART duration.

CONCLUSIONS

Despite viral suppression, persons with HIV and LTBI exhibit abnormal cytokine production accompanied by high concentrations of pro- and anti-inflammatory cytokines.

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 role of IL-1β during human immunodeficiency virus type 1 infection

Interleukin (IL)-1β is a key innate cytokine that is essential for immune activation and promoting the inflammatory process. However, abnormal elevation in IL-1β levels has been associated with unwanted clinical outcomes. IL-1β is the most extensively studied cytokine among the IL-1 family of cytokines and its role in pathology is well established. During the course of human immunodeficiency virus type 1 (HIV-1) infection, the level of this proinflammatory cytokine is increased in different anatomical compartments, particularly in lymphatic tissues, and this elevation is associated with disease progression. The aim of this review is to address the pathological roles play by IL-1β in the light of enhancing HIV-1 replication, driving immune cell depletion, and chronic immune activation. The role of IL-1β in HIV-1 transmission (sexually or vertically 'from mother-to-child') will also be discussed. Additionally, the impact of the available antiretroviral therapy regimens on the levels of IL-1β in HIV-1 treated patients is also discussed. Finally, we will provide a glance on how IL-1β could be targeted as a therapeutic strategy.

Inflammation markers and the risk of hypertension in people living with HIV

Background

The incidence of hypertension is high in people living with HIV (PLWH). High-sensitivity C-reactive protein (hsCRP), systemic inflammation response index (SIRI), and neutrophil-to-monocyte ratio (NMR) are considered economic and convenient parameters that reflect the levels of inflammation in patients. Our aim was to explore whether indirect inflammation markers are associated with hypertension in PLWH.

Methods

This was a case-control study. The case group (hypertension) comprised PLWH with hypertension, and the control group (non-hypertension) comprised sex- and age-(± 3 years)-matched PLWH without hypertension. Demographic parameters, hsCRP, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune- inflammation index (SII), SIRI, lymphocyte-to-monocyte ratio (LMR), platelet-to-neutrophil ratio (PNR), platelet-to-monocyte ratio (PMR), NMR, time to HIV diagnosis, antiretroviral therapy (ART) duration, recent CD4⁺ and CD8⁺ cell counts, recent CD4⁺/CD8⁺ ratio, recent HIV viral load (HIV-RNA),and recent ART regimen were obtained from the patients' electronic medical records. A t-test or Wilcoxon rank-sum test was performed to compare differences between the two groups, and conditional logistic regression was used to analyze the risk factors of hypertension. Correlations between inflammation markers and CD4⁺ cell counts, CD8⁺ cell counts, and CD4⁺/CD8⁺ ratio were analyzed using Spearman's correlation.

Results

In the hypertension group, body mass index (BMI), hsCRP, NLR, SII, SIRI, NMR, time to HIV diagnosis, ART duration, CD4⁺ and CD8⁺ cell counts, and CD4⁺/CD8⁺ ratio, the ratio of HIV-RNA < 100 copies/mL were all higher than those in the non-hypertension group, while the PNR was lower than that in the non-hypertension group. ART duration, CD4⁺ cell counts, HIV-RNA < 100 copies/mL, hsCRP, SIRI, and NMR were positively associated with hypertensive risk in PLWH. CD8⁺ cell counts and CD4⁺/CD8⁺ ratio was negatively associated with hypertensive risk in PLWH. SIRI was negatively correlated with CD4⁺ cell counts and CD8⁺ cell counts, but positively correlated with CD4⁺/CD8⁺ ratio.

Conclusions

We identified positive associations between inflammation markers hsCRP, SIRI, NMR and hypertensive risk in PLWH. Alleviating inflammation may help control or delay the occurrence of hypertension in PLWH.

Central obesity is a contributor to systemic inflammation and monocyte activation in virally suppressed adults with chronic HIV in Kenya

OBJECTIVES

Heightened systemic inflammation is common in obese individuals and persons with HIV (PWH) and is independently associated with an increased risk of cardiovascular diseases (CVDs). We investigated the combined effect of central obesity, a surrogate measure of visceral fat and HIV on circulating levels of inflammatory cytokines among Kenyan adults.

DESIGN

A cross-sectional study.

METHODS

We analysed and compared data from 287 virally suppressed PWH and 277 noninfected Kenyan adults, including biomarkers of gut epithelial dysfunction (intestinal fatty acid binding protein), monocyte activation (soluble CD163 and CD14) and inflammation [interleukin (IL)-1β, IL-6, TNF-α and hsCRP] by HIV/central obesity status (HIV-positive/obese, HIV-negative/obese, HIV-positive/nonobese and HIV-negative/nonobese). Central obesity was defined as waist circumference more than 80 cm for women and more than 94 cm for men. We assessed the association of HIV/obesity status with elevated biomarkers (>75th percentile) using logistic regression.

RESULTS

Median age for participants was 44 years and 37% were centrally obese. Levels of all biomarkers were higher among the HIV-positive/obese compared with the HIV-negative/nonobese (P < 0.05 for all comparisons). The HIV-positive/obese group had the greatest odds of having elevated inflammatory biomarkers compared with other groups even after adjustment of age, BMI and other conventional CVD risk factors (P < 0.05 for all). Additional adjustment for sCD163 in the multivariate model substantially attenuated the association for HIV-positive/obesity with IL-1β, IL-6 and TNF-α but not hsCRP. The contribution of HIV-positive/obesity to inflammation was independent of the degree of immunosuppression.

CONCLUSION

Central obesity is prevalent among virally suppressed African PWH and is associated with greater inflammation and monocyte activation independent of other comorbidities and HIV-specific factors.