Effects of Tobacco Usage and Antiretroviral Therapy on Biomarkers of Systemic Immune Activation in HIV-Infected Participants

TLR3 polymorphisms in HIV infected individuals naïve to ART

BACKGROUND

TLR3 polymorphisms affect the risk of HIV infection and modify the disease course. Consequently, we analyzed the association of TLR3 polymorphism (rs5743312, rs3775296, and rs3775291) with susceptilbity to HIV-1 acquisition and disease progression.

METHOD

This is a cross-sectional study. Genotyping of TLR3 polymorphisms were completed by the utilization of the PCR-RFLP technique in 153 HIV naive subjects and 158 healthy controls.

RESULT

A haplotype is a physical grouping of genomic variants that tend to be inherited together. The TCC haplotype was increased in HIV infected individuals compared with healthy controls (0.05% versus 0.03%). TLR3 rs3775291CT genotype was associated to the early stage of HIV infection (OR=2.19, P=0.04), with a higher occurrence in advance stage of HIV infection when contrasted with healthy controls (41.2% versus 32.3%). TLR3 rs3775296 CA genotype was likely to be associated with intermediate stage of HIV infection (19.5% versus 31.6%, OR=0.42, P=0.06). TLR3 rs5743312TT genotype was used to be greater prevalence in advanced stage of HIV infection compared with healthy controls (2.9% versus 1.9%). TLR3 rs3775296CA genotype was less prevalent in HIV subjects devouring tobacco when contrasted with non-users (9.1% versus 34.9%, OR=0.25, P=0.09). TLR3 rs3775296AA and rs3775291CT and TT genotypes have been overrepresented in HIV subjects using alcohol when contrasted with non-users (5.6% versus 1.1%, OR=1.83, P=0.67; 50.0% versus 42.2%, OR=1.84, P=0.31; 5.6% versus 3.3%, OR=2.70, P=0.50). In multivariate examination, rs5743312TT genotype showed a greater risk for HIV infection (OR=1.86, P=0.50).

CONCLUSION

TLR3 rs3775291 C/T polymorphism may assist the risk of disease progression in alcohol consumers. TLR3 rs3775291 CT genotype may enhance the disease progression whereas the TLR3 rs3775296 CA genotype may protect for disease progression.

An Emerging Syndemic of Smoking and Cardiopulmonary Diseases in People Living with HIV in Africa

BACKGROUND

African countries have the highest number of people living with HIV (PWH). The continent is home to 12% of the global population, but accounts for 71% of PWH globally. Antiretroviral therapy has played an important role in the reduction of the morbidity and mortality rates for HIV, which necessitates increased surveillance of the threats from pernicious risks to which PWH who live longer remain exposed. This includes cardiopulmonary comorbidities, which pose significant public health and economic challenges. A significant contributor to the cardiopulmonary comorbidities is tobacco smoking. Indeed, globally, PWH have a 2-4-fold higher utilization of tobacco compared to the general population, leading to endothelial dysfunction and atherogenesis that result in cardiopulmonary diseases, such as chronic obstructive pulmonary disease and coronary artery disease. In the context of PWH, we discuss (1) the current trends in cigarette smoking and (2) the lack of geographically relevant data on the cardiopulmonary conditions associated with smoking; we then review (3) the current evidence on chronic inflammation induced by smoking and the potential pathways for cardiopulmonary disease and (4) the multifactorial nature of the syndemic of smoking, HIV, and cardiopulmonary diseases. This commentary calls for a major, multi-setting cohort study using a syndemics framework to assess cardiopulmonary disease outcomes among PWH who smoke.

CONCLUSION

We call for a parallel program of implementation research to promote the adoption of evidence-based interventions, which could improve health outcomes for PWH with cardiopulmonary diseases and address the health inequities experienced by PWH in African countries.

The relationship of smoking and unhealthy alcohol use to the HIV care continuum among people with HIV in an integrated health care system

INTRODUCTION

Smoking tobacco and unhealthy alcohol use may negatively influence HIV care continuum outcomes but have not been examined in combination.

METHODS

Participants were people with HIV (PWH) in Kaiser Permanente Northern California. Predictors included smoking status and unhealthy alcohol use (exceeding daily and/or weekly limits) reported by patients during primary care screening (index date). Outcomes were based on not achieving the following steps in the care continuum: linkage to HIV care (≥1 visit within 90 days of newly identified HIV diagnosis), retention (2+ in-person visits, 60+ days apart) and HIV RNA control (<75 copies/mL). Adjusted odds ratios (ORs) were obtained from separate logistic regression models for each outcome associated with smoking and unhealthy alcohol use independently and combined.

RESULTS

The overall sample (N = 8958) had a mean age of 48.0 years; was 91.3 % male; 54.0 % white, 17.6 % Latino, 15.1 % black, and 9.6 % other race/ethnicity. Smoking was associated with higher odds of not being linked to HIV care (OR = 1.60 [95 % CI 1.03-2.48]), not retained (OR = 1.30 [95 % CI 1.13-1.50]), and HIV RNA not in control (OR = 1.91 [95 % CI 1.60-2.27]). Alcohol measures were not independently associated with outcomes. The combination of unhealthy alcohol use and smoking (versus neither) was associated with higher odds of not being linked to care (OR = 2.83 [95 % CI 1.40-5.71]), although the interaction did not reach significance (p = 0.18).

CONCLUSIONS

In this large sample of PWH in an integrated health care system, smoking, both independently and in combination with unhealthy alcohol use, was associated with worse HIV care continuum outcomes.

Differential Responsiveness of the Platelet Biomarkers, Systemic CD40 Ligand, CD62P, and Platelet-Derived Growth Factor-BB, to Virally-Suppressive Antiretroviral Therapy

Systemic biomarkers of inflammation, including cytokines and chemokines, are potentially useful in the management of both HIV infection and non-AIDS-defining disorders. However, relatively little is known about the utility of measurement of circulating biomarkers of platelet activation as a strategy to monitor the efficacy of combination antiretroviral therapy (cART), as well as the persistence of systemic inflammation following virally-suppressive therapy in HIV-infected persons. These issues have been addressed in the current study to which a cohort consisting of 199 HIV-infected participants was recruited, 100 of whom were cART-naïve and the remainder cART-treated and virally-suppressed. Fifteen healthy control participants were included for comparison. The study focused on the effects of cART on the responsiveness of three biomarkers of platelet activation, specifically soluble CD40 ligand (sCD40L), sCD62P (P-selectin), and platelet-derived growth factor-BB (PDGF-BB), measured using multiplex suspension bead array technology. Most prominently sCD40L in particular, as well as sCD62P, were significantly elevated in the cART-naïve group relative to both the cART-treated and healthy control groups. However, levels of PDGF-BB were of comparable magnitude in both the cART-naïve and -treated groups, and significantly higher than those of the control group. Although remaining somewhat higher in the virally-suppressed group relative to healthy control participants, these findings identify sCD40L, in particular, as a potential biomarker of successful cART, while PDGF-BB may be indicative of persistent low-level antigenemia.

Impact of HIV infection on aging and immune status

Introduction: Thanks to antiretroviral therapy (ART), persons living with HIV (PLWH), have a longer life expectancy. However, immune activation and inflammation remain elevated, even after viral suppression, and contribute to morbidity and mortality in these individuals.Areas covered: We review aspects related to immune activation and inflammation in PLWH, their consequences, and the potential strategies to reduce immune activation in HIV-infected individuals on ART.Expert opinion: When addressing a problem, it is necessary to thoroughly understand the topic. This is the main limitation faced when dealing with immune activation and inflammation in PLWH since there is no consensus on the ideal markers to evaluate immune activation or inflammation. To date, the different interventions that have addressed this problem by targeting specific mediators have not been able to significantly reduce immune activation or its consequences. Given that there is currently no curative intervention for HIV infection, more studies are necessary to understand the mechanism underlying immune activation and help to identify potential therapeutic targets that contribute to improving the life expectancy of HIV-infected individuals.

Independent and Combined Effects of Nicotine or Chronic Tobacco Smoking and HIV on the Brain: A Review of Preclinical and Clinical Studies

Tobacco smoking is highly prevalent among HIV-infected individuals. Chronic smokers with HIV showed greater cognitive deficits and impulsivity, and had more psychopathological symptoms and greater neuroinflammation than HIV non-smokers or smokers without HIV infection. However, preclinical studies that evaluated the combined effects of HIV-infection and tobacco smoking are scare. The preclinical models typically used cell cultures or animal models that involved specific HIV viral proteins or the administration of nicotine to rodents. These preclinical models consistently demonstrated that nicotine had neuroprotective and anti-inflammatory effects, leading to cognitive enhancement. Although the major addictive ingredient in tobacco smoking is nicotine, chronic smoking does not lead to improved cognitive function in humans. Therefore, preclinical studies designed to unravel the interactive effects of chronic tobacco smoking and HIV infection are needed. In this review, we summarized the preclinical studies that demonstrated the neuroprotective effects of nicotine, the neurotoxic effects of the HIV viral proteins, and the scant literature on nicotine or tobacco smoke in HIV transgenic rat models. We also reviewed the clinical studies that evaluated the neurotoxic effects of tobacco smoking, HIV infection and their combined effects on the brain, including studies that evaluated the cognitive and behavioral assessments, as well as neuroimaging measures. Lastly, we compared the different approaches between preclinical and clinical studies, identified some gaps and proposed some future directions. Graphical abstract Independent and combined effects of HIV and tobacco/nicotine. Left top and bottom panels: Both clinical studies of HIV infected persons and preclinical studies using viral proteins in vitro or in vivo in animal models showed that HIV infection could lead to neurotoxicity and neuroinflammation. Right top and bottom panels: While clinical studies of tobacco smoking consistently showed deleterious effects of smoking, clinical and preclinical studies that used nicotine show mild cognitive enhancement, neuroprotective and possibly anti-inflammatory effects. In the developing brain, however, nicotine is neurotoxic. Middle overlapping panels: Clinical studies of persons with HIV who were smokers typically showed additive deleterious effects of HIV and tobacco smoking. However, in the preclinical studies, when nicotine was administered to the HIV-1 Tg rats, the neurotoxic effects of HIV were attenuated, but tobacco smoke worsened the inflammatory cascade.

A Cross-Sectional Analysis of Tobacco Use and Concurrent Alcohol and Substance Use Among Patients Living with HIV/HCV Co-infection: Findings from a Large Urban Tertiary Center

This study aimed to assess the prevalence of and factors associated with tobacco use among patients living with HIV/HCV co-infection. Patient reported outcomes (PROs) were analyzed of patients living with HIV/HCV co-infection (n = 313) who presented for clinical evaluation and treatment of HCV between 2013 and 2017 at a university-affiliated HIV/HCV Co-infection Clinic. The prevalence of tobacco use in patients living with HIV/HCV co-infection was 48%. Compared to non-smokers, a higher proportion of tobacco smokers had substance use disorders and concurrent alcohol and substance use. In the multivariate analysis, concurrent alcohol and substance use was positively associated with tobacco use. The findings suggest clinical interventions are urgently needed to reduce tobacco use among patients living with HIV/HCV co-infection—a doubly-vulnerable immunocompromised population. Otherwise, failed efforts to dedicate resources and targeted behavioral interventions for this respective population will inhibit survival—especially considering the recent and evolving COVID-19 pandemic.

Differential packaging of inflammatory cytokines/ chemokines and oxidative stress modulators in U937 and U1 macrophages-derived extracellular vesicles upon exposure to tobacco constituents

Smoking, which is highly prevalent in HIV-infected populations, has been shown to exacerbate HIV replication, in part via the cytochrome P450 (CYP)-induced oxidative stress pathway. Recently, we have shown that extracellular vesicles (EVs), derived from tobacco- and/or HIV-exposed macrophages, alter HIV replication in macrophages by cell-cell interactions. We hypothesize that cigarette smoke condensate (CSC) and/or HIV-exposed macrophage-derived EVs carry relatively high levels of pro-oxidant and pro-inflammatory cargos and/or low levels of antioxidant and anti-inflammatory cargos, which are key mediators for HIV pathogenesis. Therefore, in this study, we investigated differential packaging of pro- and anti-inflammatory cytokines/chemokines and pro- and anti-oxidant contents in EVs after CSC exposure to myeloid cells (uninfected U937 and HIV-infected U1 cells). Our results showed that relatively long to short exposures with CSC increased the expression of cytokines in EVs isolated from HIV-infected U1 macrophages. Importantly, pro-inflammatory cytokines, especially IL-6, were highly packaged in EVs isolated from HIV-infected U1 macrophages upon both long and short-term CSC exposures. In general, anti-inflammatory cytokines, particularly IL-10, had a lower packaging in EVs, while packaging of chemokines was mostly increased in EVs upon CSC exposure in both HIV-infected U1 and uninfected U937 macrophages. Moreover, we observed higher expression of CYPs (1A1 and 1B1) and lower expression of antioxidant enzymes (SOD-1 and catalase) in EVs from HIV-infected U1 macrophages than in uninfected U937 macrophages. Together, they are expected to increase oxidative stress factors in EVs derived from HIV-infected U1 cells. Taken together, our results suggest packaging of increased level of oxidative stress and inflammatory elements in the EVs upon exposure to tobacco constituents and/or HIV to myeloid cells, which would ultimately enhance HIV replication in macrophages via cell-cell interactions.

Extracellular Vesicles in Smoking-Mediated HIV Pathogenesis and their Potential Role in Biomarker Discovery and Therapeutic Interventions

In the last two decades, the mortality rate in people living with HIV/AIDS (PLWHA) has decreased significantly, resulting in an almost normal longevity in this population. However, a large portion of this population still endures a poor quality of life, mostly due to an increased inclination for substance abuse, including tobacco smoking. The prevalence of smoking in PLWHA is consistently higher than in HIV negative persons. A predisposition to cigarette smoking in the setting of HIV potentially leads to exacerbated HIV replication and a higher risk for developing neurocognitive and other CNS disorders. Oxidative stress and inflammation have been identified as mechanistic pathways in smoking-mediated HIV pathogenesis and HIV-associated neuropathogenesis. Extracellular vesicles (EVs), packaged with oxidative stress and inflammatory agents, show promise in understanding the underlying mechanisms of smoking-induced HIV pathogenesis via cell-cell interactions. This review focuses on recent advances in the field of EVs with an emphasis on smoking-mediated HIV pathogenesis and HIV-associated neuropathogenesis. This review also provides an overview of the potential applications of EVs in developing novel therapeutic carriers for the treatment of HIV-infected individuals who smoke, and in the discovery of novel biomarkers that are associated with HIV-smoking interactions in the CNS.

Bidirectional Associations among Nicotine and Tobacco Smoke, NeuroHIV, and Antiretroviral Therapy

People living with HIV (PLWH) in the antiretroviral therapy (ART) era may lose more life-years to tobacco use than to HIV. Yet, smoking rates are more than twice as high among PLWH than the general population, contributing not just to mortality but to other adverse health outcomes, including neurocognitive deficits (neuroHIV). There is growing evidence that synergy with chronic inflammation and immune dysregulation that persists despite ART may be one mechanism by which tobacco smoking contributes to neuroHIV. This review will summarize the differential effects of nicotine vs tobacco smoking on inflammation in addition to the effects of tobacco smoke components on HIV disease progression. We will also discuss biomarkers of inflammation via neuroimaging as well as biomarkers of nicotine dependence (e.g., nicotine metabolite ratio). Tobacco smoking and nicotine may impact ART drug metabolism and conversely, certain ARTs may impact nicotine metabolism. Thus, we will review these bidirectional relationships and how they may contribute to neuroHIV and other adverse outcomes. We will also discuss the effects of tobacco use on the interaction between peripheral organs (lungs, heart, kidney) and subsequent CNS function in the context of HIV. Lastly, given the dramatic rise in the use of electronic nicotine delivery systems, we will discuss the implications of vaping on these processes. Despite the growing recognition of the importance of addressing tobacco use among PLWH, more research is necessary at both the preclinical and clinical level to disentangle the potentially synergistic effects of tobacco use, nicotine, HIV, cognition and immune dysregulation, as well as identify optimal approaches to reduce tobacco use. Graphical Abstract Proposed model of the relationships among HIV, ART, smoking, inflammation, and neurocognition. Solid lines represent relationships supported by evidence. Dashed lines represent relationships for which there is not enough evidence to make a conclusion. (a) HIV infection produces elevated levels of inflammation even among virally suppressed individuals. (b) HIV is associated with deficits in cognition function. (c) Smoking rates are higher among PLWH, compared to the general population. (d) The nicotine metabolite ratio (NMR) is associated with smoking behavior. (e) HIV and tobacco use are both associated with higher rates of psychiatric comorbidities, such as depression, and elevated levels of chronic stress. These factors may represent other mechanisms linking HIV and tobacco use. (f) The relationship between nicotine, tobacco smoking, and inflammation is complex, but it is well-established that smoking induces inflammation; the evidence for nicotine as anti-inflammatory is supported in some studies, but not others. (g) The relationship between tobacco use and neurocognition may differ for the effects of nicotine (acute nicotine use may have beneficial effects) vs. tobacco smoking (chronic use may impair cognition). (h) Elevated levels of inflammation may be associated with deficits in cognition. (i) PLWH may metabolize nicotine faster than those without HIV; the mechanism is not yet known and the finding needs validation in larger samples. We also hypothesize that if HIV-infection increases nicotine metabolism, then we should observe an attenuation effect once ART is initiated. (j) It is possible that the increase in NMR is due to ART effects on CYP2A6. (k) We hypothesize that faster nicotine metabolism may result in higher levels of inflammation since nicotine has anti-inflammatory properties.