Immune cell phenotyping in low blood volumes for assessment of cardiovascular disease risk, development, and progression: a pilot study

Social Determinants modulate NK cell activity via obesity, LDL, and DUSP1 signaling

Adverse social determinants of health (aSDoH) are associated with obesity and related comorbidities like diabetes, cardiovascular disease, and cancer. Obesity is also associated with natural killer cell (NK) dysregulation, suggesting a potential mechanistic link. Therefore, we measured NK phenotypes and function in a cohort of African-American (AA) women from resource-limited neighborhoods. Obesity was associated with reduced NK cytotoxicity and a shift towards a regulatory phenotype. In vitro, LDL promoted NK dysfunction, implicating hyperlipidemia as a mediator of obesity-related immune dysregulation. Dual specific phosphatase 1 (DUSP1) was induced by LDL and was upregulated in NK cells from subjects with obesity, implicating DUSP1 in obesity-mediated NK dysfunction. In vitro, DUSP1 repressed LAMP1/CD107a, depleting NK cells of functional lysosomes to prevent degranulation and cytokine secretion. Together, these data provide novel mechanistic links between aSDoH, obesity, and immune dysregulation that could be leveraged to improve outcomes in marginalized populations.

Innate and Adaptive Immunity-Related Markers as Predictors of the Short-Term Progression of Subclinical Atherosclerosis in Middle-Aged Patients

Assessment of inflammation is a promising approach to monitoring the progression of asymptomatic atherosclerosis. The aim of the present study was to investigate the predictive value of innate and adaptive immunity-related markers, in relation to the short-term progression of subclinical atherosclerosis. The study included 183 patients aged 40-64 years who underwent duplex scanning of the carotid and lower limb arteries at two visits with an interval of 12-24 months between examinations. Phenotyping of circulating lymphocytes and monocytes subpopulations were performed through flow cytometry. An increase in the number of circulating TLR4-positive intermediate monocytes (>447.0-467.0 cells/μL) was an independent predictor of the short-term progression of lower limb artery atherosclerosis (p < 0.0001) and polyvascular atherosclerosis (p = 0.003). The assessment of TLR4-positive monocytes significantly improved the prognostic model for the progression of lower limb arterial atherosclerosis (C-index 0.728 (0.642-0.815) versus 0.637 (0.539-0.735); p = 0.038). An increase in the number of circulating TLR4-positive intermediate monocytes was an independent predictor of the short-term progression of lower limb artery and polyvascular atherosclerosis. Their inclusion into models containing conventional risk factors significantly improved their prognostic effectiveness regarding lower limb artery atherosclerosis progression.

Neighborhood socioeconomic deprivation and individual-level socioeconomic status are associated with dopamine-mediated changes to monocyte subset CCR2 expression via a cAMP-dependent pathway

Social determinants of health (SDoH) include socioeconomic, environmental, and psychological factors that impact health. Neighborhood socioeconomic deprivation (NSD) and low individual-level socioeconomic status (SES) are SDoH that associate with incident heart failure, stroke, and cardiovascular mortality, but the underlying biological mechanisms are not well understood. Previous research has demonstrated an association between NSD, in particular, and key components of the neural-hematopoietic-axis including amygdala activity as a marker of chronic stress, bone marrow activity, and arterial inflammation. Our study further characterizes the role of NSD and SES as potential sources of chronic stress related to downstream immunological factors in this stress-associated biologic pathway. We investigated how NSD, SES, and catecholamine levels (as proxy for sympathetic nervous system activation) may influence monocytes which are known to play a significant role in atherogenesis. First, in an ex vivo approach, we treated healthy donor monocytes with biobanked serum from a community cohort of African Americans at risk for CVD. Subsequently, the treated monocytes were subjected to flow cytometry for characterization of monocyte subsets and receptor expression. We determined that NSD and serum catecholamines (namely dopamine [DA] and norepinephrine [NE]) associated with monocyte C-C chemokine receptor type 2 (CCR2) expression (p < 0.05), a receptor known to facilitate recruitment of monocytes towards arterial plaques. Additionally, NSD associated with catecholamine levels, especially DA in individuals of low SES. To further explore the potential role of NSD and the effects of catecholamines on monocytes, monocytes were treated in vitro with epinephrine [EPI], NE, or DA. Only DA increased CCR2 expression in a dose-dependent manner (p < 0.01), especially on non-classical monocytes (NCM). Furthermore, linear regression analysis between D2-like receptor surface expression and surface CCR2 expression suggested D2-like receptor signaling in NCM. Indicative of D2-signaling, cAMP levels were found to be lower in DA-treated monocytes compared to untreated controls (control 29.78 pmol/ml vs DA 22.97 pmol/ml; p = 0.038) and the impact of DA on NCM CCR2 expression was abrogated by co-treatment with 8-CPT, a cAMP analog. Furthermore, Filamin A (FLNA), a prominent actin-crosslinking protein, that is known to regulate CCR2 recycling, significantly decreased in DA-treated NCM (p < 0.05), indicating a reduction of CCR2 recycling. Overall, we provide a novel immunological mechanism, driven by DA signaling and CCR2, for how NSD may contribute to atherogenesis. Future studies should investigate the importance of DA in CVD development and progression in populations disproportionately experiencing chronic stress due to SDoH.

Tetraplex Immunophenotyping of Cell Surface Proteomes via Synthesized Plasmonic Nanotags and Portable Raman Spectroscopy

Multiplex immunophenotyping of cell surface proteomes is useful for cell characterization as well as providing valuable information on a patient's physiological or pathological state. Current methods for multiplex immunophenotyping of cell surface proteomes still have associated technical pitfalls in terms of limited multiplexing capability, challenging result interpretation, and large equipment footprint limited to use in a laboratory setting. Herein, we presented a portable surface-enhanced Raman spectroscopy (SERS) assay for multiplex cell surface immunophenotyping. We synthesized and functionalized customizable SERS nanotags for cell labeling and subsequent signal measurement using a portable Raman spectrometer. We extensively evaluated and validated the analytical assay performance of the portable SERS immunophenotyping assay in two different cellular models (red blood cells and breast cancer cells). In terms of analytical specificity, the cell surface immunophenotyping of both red blood cells and breast cancer cells correlated well with flow cytometry. The portable SERS immunophenotyping assay also has comparable analytical repeatability to flow cytometry, with coefficient of variation values of 21.89-23.33% and 6.88-17.32% for detecting red blood cells and breast cancer cells, respectively. The analytical detection limits were 77 cells/mL for red blood cells and 1-17 cells/mL for breast cancer cells. As an alternative to flow cytometry, the portable SERS immunophenotyping assay demonstrated excellent analytical assay performance and possessed advantages such as quick sample-to-result turnaround time, multiplexing capability, and small equipment footprint.

LDL associates with pro-inflammatory monocyte subset differentiation and increases in chemokine receptor profile expression in African Americans

BACKGROUND

In the United States, African Americans (AAs) have greater risk for Class III obesity and cardiovascular disease (CVD). Previous reports suggest that AAs have a different immune cell profile when compared to Caucasians.

METHODS

The immune cell profile of AAs was characterized by flow cytometry using two experimental setups: ex vivo (N = 40) and in vitro (N = 10). For ex vivo experiments, PBMC were treated with participant serum to understand how lipid contents may contribute to monocyte phenotypic differences. For in vitro experiments, monocytes were low-density lipoprotein (LDL)- or vehicle-treated for four hours and subsequently analyzed by flow cytometry and RT-qPCR.

RESULTS

When PBMCs were treated with participant sera, subsequent multivariable regression analysis revealed that serum triglycerides and LDL levels were associated with monocyte subset differences. In vitro LDL treatment of monocytes induced a phenotypic switch in monocytes away from classical monocytes accompanied by subset-specific chemokine receptor CCR2 and CCR5 expression changes. These observed changes are partially translation-dependent as determined by co-incubation with cycloheximide.

CONCLUSIONS

LDL treatment of monocytes induces a change in monocyte subsets and increases CCR2/CCR5 expression in a subset-specific manner. Understanding the molecular mechanisms could prove to have CVD-related therapeutic benefits, especially in high-risk populations with hyperlipidemia and increased risk for CVD.

Preparation and in vitro and in vivo Evaluation Of Panax Notoginseng Saponins-loaded Nanoparticles Coated with Trimethyl Chitosan Derivatives

In this study, novel Panax notoginseng saponins (PNS)-loaded nanoparticles coated with the Trimethyl chitosan (TMC) derivatives TMC-VB₁₂ and TMC-Cys (PPTT-NPs) were developed to improve the oral absorption of the constituents. PPTT-NPs were prepared by the double emulsion method and showed different encapsulation effects on the major components, including Rg1, Rb1, and R1, in PNS. In vivo, the absorption rate constant and apparent absorption coefficient of PPTT-NPs were higher than PNS solution. These findings preliminarily proved that PPTT-NPs can promote intestinal absorption to a certain extent. The pharmacokinetic results indicated that the blood concentration and the area under the curve of Rg1 and Rb1 in the PPTT-NPs were higher than Xueshuantong capsules. The cell viability of PPTT-NPs was above 90% within 25-150 μg/mL. PPTT-NPs promoted the cellular uptake of PNS by receptor-mediated endocytosis. In summary, NPs coated with TMC-VB₁₂ and TMC-Cys can be used as promising drug delivery systems.

Geospatial Analysis of Neighborhood Environmental Stress in Relation to Biological Markers of Cardiovascular Health and Health Behaviors in Women: Protocol for a Pilot Study

Background

Innovative analyses of cardiovascular (CV) risk markers and health behaviors linked to neighborhood stressors are essential to further elucidate the mechanisms by which adverse neighborhood social conditions lead to poor CV outcomes. We propose to objectively measure physical activity (PA), sedentary behavior, and neighborhood stress using accelerometers, GPS, and real-time perceived ecological momentary assessment via smartphone apps and to link these to biological measures in a sample of White and African American women in Washington, DC, neighborhoods.

Objective

The primary aim of this study is to test the hypothesis that living in adverse neighborhood social conditions is associated with higher stress-related neural activity among 60 healthy women living in high or low socioeconomic status neighborhoods in Washington, DC. Sub-aim 1 of this study is to test the hypothesis that the association is moderated by objectively measured PA using an accelerometer. A secondary objective is to test the hypothesis that residing in adverse neighborhood social environment conditions is related to differences in vascular function. Sub-aim 2 of this study is to test the hypothesis that the association is moderated by objectively measured PA. The third aim of this study is to test the hypothesis that adverse neighborhood social environment conditions are related to differences in immune system activation.

Methods

The proposed study will be cross-sectional, with a sample of at least 60 women (30 healthy White women and 30 healthy Black women) from Wards 3 and 5 in Washington, DC. A sample of the women (n=30) will be recruited from high-income areas in Ward 3 from census tracts within a 15% of Ward 3’s range for median household income. The other participants (n=30) will be recruited from low-income areas in Wards 5 from census tracts within a 15% of Ward 5’s range for median household income. Finally, participants from Wards 3 and 5 will be matched based on age, race, and BMI. Participants will wear a GPS unit and accelerometer and report their stress and mood in real time using a smartphone. We will then examine the associations between GPS-derived neighborhood variables, stress-related neural activity measures, and adverse biological markers.

Results

The National Institutes of Health Institutional Review Board has approved this study. Recruitment will begin in the summer of 2021.

Conclusions

Findings from this research could inform the development of multilevel behavioral interventions and policies to better manage environmental factors that promote immune system activation or psychosocial stress while concurrently working to increase PA, thereby influencing CV health.

International Registered Report Identifier (IRRID)

PRR1-10.2196/29191

Multilevel mobile health approach to improve cardiovascular health in resource-limited communities with Step It Up: a randomised controlled trial protocol targeting physical activity

INTRODUCTION

Although physical activity (PA) reduces cardiovascular disease (CVD) risk, physical inactivity remains a pressing public health concern, especially among African American (AA) women in the USA. PA interventions focused on AA women living in resource-limited communities with scarce PA infrastructure are needed. Mobile health (mHealth) technology can increase access to PA interventions. We describe the development of a clinical protocol for a multilevel, community-based, mHealth PA intervention for AA women.

METHODS AND ANALYSIS

An mHealth intervention targeting AA women living in resource-limited Washington, DC communities was developed based on the socioecological framework for PA. Over 6 months, we will use a Sequential Multi-Assignment, Randomized Trial approach to compare the effects on PA of location-based remote messaging (named 'tailored-to-place') to standard remote messaging in an mHealth intervention. Participants will be randomised to a remote messaging intervention for 3 months, at which point the intervention strategy will adapt based on individuals' PA levels. Those who do not meet the PA goal will be rerandomised to more intensive treatment. Participants will be followed for another 3 months to determine the contribution of each mHealth intervention to PA level. This protocol will use novel statistical approaches to account for the adaptive strategy. Finally, effects of PA changes on CVD risk biomarkers will be characterised.

ETHICS AND DISSEMINATION

This protocol has been developed in partnership with a Washington, DC-area community advisory board to ensure feasibility and acceptability to community members. The National Institutes of Health Intramural IRB approved this research and the National Heart, Lung, and Blood Institute provided funding. Once published, results of this work will be disseminated to community members through presentations at community advisory board meetings and our quarterly newsletter.

TRIAL REGISTRATION NUMBER

NCT03288207.

Hiding in plain sight - platelets, the silent carriers of HIV-1

There are approximately 38 million people globally living with Human immunodeficiency virus 1 (HIV-1) and given the tremendous success of combination antiretroviral therapy (cART) this has dramatically reduced mortality and morbidity with prevention benefits. However, HIV-1 persists during cART within the human body and re-appears upon cART interruption. This HIV-1 reservoir remains a barrier to cure with cellular sites of viral persistence not fully understood. In this study we provide evidence corroborating a recently published article in STM demonstrating the role of platelets as a novel cellular disseminator of HIV-1 particles in the setting of viral suppression. Using classical transmission electron microscopy with and without immunogold labeling, we visualize HIV-1 in both platelets and monocytes in cART suppressed HIV donors. Our study suggests that due to the close proximity of platelets and monocytes an alternative life cycle of HIV-1 cycling within monocytes and platelets without the need of active replication under cART occurs. Our findings are supported by the lack of detectable HIV-1 particles in platelets derived from HIV uninfected donors or the 'Berlin' patient suggesting that platelets may serve as an underappreciated hidden bearer for HIV-1 and should be considered in HIV remission studies and trials.

Health Disparities in COVID-19: Addressing the Role of Social Determinants of Health in Immune System Dysfunction to Turn the Tide

It is evident that health disparities exist during the COVID-19 pandemic, a pandemic caused by the novel coronavirus SARS-CoV-2. Underlying reasons for COVID-19 health disparities are multi-factorial. However, social determinants, including those regarding socioeconomic status, social inequalities, health behaviors, and stress, may have implications on these disparities. Exposure to one or more of these social determinants is associated with heightened inflammatory responses, particularly increases in the cytokine interleukin-6 (IL-6), as well as immune system dysfunction. Thus, an amplified effect during COVID-19 could occur, potentially resulting in vulnerable patients experiencing an intensified cytokine storm due to a hyperactive and dysfunctional immune response. Further understanding how social determinants play a mechanistic role in COVID-19 disparities could potentially help reduce health disparities overall and in future pandemics.

COVID-19: Growing Health Disparity Gaps and an Opportunity for Health Behavior Discovery?

Recently, racial and ethnic disparities within the current coronavirus disease-2019 (COVID-19) pandemic at the state level have received attention and notably highlight the ongoing issues surrounding health disparities within the United States. Among the discussions around health disparities lies a discussion on the role of psychosocial stress during this pandemic, especially with broadly applied social distancing and isolation recommendations. In nonpandemic times, psychosocial stressors have a significant association with physiological responses and behavioral responses. Within the current pandemic, increased attention on health-promoting behaviors, such as cooking and physical activity, has occurred. However, based on disparities from structural racism and socioeconomic effects on neighborhood environments, we may see a limiting value to the possible mitigating role of health behaviors within some disparate communities. We present in this perspective that there may be a role for behavioral interventions to mitigate psychosocial stressors and promote health behaviors. It may also be important to consider the use of multilevel behavioral interventions designed in the context of environmental and perceptual barriers during the COIVD-19 pandemic.