Mortality in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE)

OBJECTIVE

We report mortality outcomes in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE) among people with type 2 diabetes diagnosed within 10 years and no recent history of cardiovascular events or cancer.

RESEARCH DESIGN AND METHODS

Overall mortality rates and major causes of death were assessed over an average of 5 years of follow-up. Cause of death was adjudicated centrally by a committee masked to treatment assignment. We examined baseline covariates and the 10-year Framingham Risk Score for associations.

RESULTS

Mortality rate was low (0.59 per 100 participant-years). Participants who died during follow-up were likely to be older, be male, have a history of hypertension, have a history of smoking, and have moderate albuminuria. The two most common underlying causes of death were "cardiovascular-cause" (a composite of underlying causes) (38.6%) and cancer (26.8%). There were no differences by treatment group.

CONCLUSIONS

Among people with diabetes of relatively short duration, cause of death was varied. Attention to health risks beyond cardiovascular diseases is warranted.

Impact of Glucose-Lowering Medications on Health-Related Quality of Life in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE)

OBJECTIVE

Diabetes is associated with reduced health-related quality of life (HRQoL). Information on the relationship between HRQoL and glucose-lowering medications in recently diagnosed type 2 diabetes (T2D) is limited. We assessed changes in HRQoL in participants with T2D receiving metformin plus one of four glucose-lowering medications in Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE).

RESEARCH DESIGN AND METHODS

A total of 5,047 participants, baseline mean age 57 years, with <10 years T2D duration and glycated hemoglobin level 6.8-8.5% and taking metformin monotherapy, were randomly assigned to glargine, glimepiride, liraglutide, or sitagliptin. HRQoL was evaluated at baseline for 4,885 participants, and at years 1, 2, and 3, with use of the self-administered version of the Quality of Well-being Scale (QWB-SA) and SF-36 physical (PCS) and mental (MCS) component summary scales. Linear models were used to analyze changes in HRQoL over time in intention-to-treat analyses.

RESULTS

None of the medications worsened HRQoL. There were no differences in QWB-SA or MCS by treatment group at any time point. PCS scores improved with liraglutide versus other groups at year 1 only. Greater weight loss during year 1 explained half the improvement in PCS scores with liraglutide versus glargine and glimepiride. Liraglutide participants in the upper tertile of baseline BMI showed the greatest improvement in PCS scores at year 1.

CONCLUSIONS

Adding liraglutide to metformin in participants within 10 years of T2D diagnosis showed improvement in the SF-36 PCS in comparisons with the other medications at 1 year, which was no longer significant at years 2 and 3. Improvement was related to weight loss and baseline BMI.

Genetic control of the dynamic transcriptional response to immune stimuli and glucocorticoids at single-cell resolution

Synthetic glucocorticoids, such as dexamethasone, have been used as a treatment for many immune conditions, such as asthma and, more recently, severe COVID-19. Single-cell data can capture more fine-grained details on transcriptional variability and dynamics to gain a better understanding of the molecular underpinnings of inter-individual variation in drug response. Here, we used single-cell RNA-seq to study the dynamics of the transcriptional response to glucocorticoids in activated peripheral blood mononuclear cells from 96 African American children. We used novel statistical approaches to calculate a mean-independent measure of gene expression variability and a measure of transcriptional response pseudotime. Using these approaches, we showed that glucocorticoids reverse the effects of immune stimulation on both gene expression mean and variability. Our novel measure of gene expression response dynamics, based on the diagonal linear discriminant analysis, separated individual cells by response status on the basis of their transcriptional profiles and allowed us to identify different dynamic patterns of gene expression along the response pseudotime. We identified genetic variants regulating gene expression mean and variability, including treatment-specific effects, and showed widespread genetic regulation of the transcriptional dynamics of the gene expression response.

Suppression of lusitropy as a disease mechanism in cardiomyopathies

In cardiac muscle the action of adrenaline on β1 receptors of heart muscle cells is essential to adjust cardiac output to the body's needs. Adrenergic activation leads to enhanced contractility (inotropy), faster heart rate (chronotropy) and faster relaxation (lusitropy), mainly through activation of protein kinase A (PKA). Efficient enhancement of heart output under stress requires all of these responses to work together. Lusitropy is essential for shortening the heartbeat when heart rate increases. It therefore follows that, if the lusitropic response is not present, heart function under stress will be compromised. Current literature suggests that lusitropy is primarily achieved due to PKA phosphorylation of troponin I (TnI) and phospholamban (PLB). It has been well documented that PKA-induced phosphorylation of TnI releases Ca2+ from troponin C faster and increases the rate of cardiac muscle relaxation, while phosphorylation of PLB increases SERCA activity, speeding up Ca2+ removal from the cytoplasm. In this review we consider the current scientific evidences for the connection between suppression of lusitropy and cardiac dysfunction in the context of mutations in phospholamban and thin filament proteins that are associated with cardiomyopathies. We will discuss what advances have been made into understanding the physiological mechanism of lusitropy due to TnI and PLB phosphorylation and its suppression by mutations and we will evaluate the evidence whether lack of lusitropy is sufficient to cause cardiomyopathy, and under what circumstances, and consider the range of pathologies associated with loss of lusitropy. Finally, we will discuss whether suppressed lusitropy due to mutations in thin filament proteins can be therapeutically restored.

Relations of postural change in blood pressure with hypertension-mediated organ damage in middle-aged adults of the Framingham heart study: A cross-sectional study

Background

Dysregulation of compensatory mechanisms to regulate blood pressure (BP) upon postural change is a phenotype of BP variability and an emerging risk factor for cardiovascular outcomes.

Materials and methods

We assessed postural change in BP (starting 2 min after standing from a supine position), carotid-femoral pulse wave velocity (cfPWV), and markers of hypertension-mediated organ damage (HMOD) in the heart, kidney, and brain in Framingham Third Generation, Omni-2, and New Offspring Spouse Cohort participants. We related vascular measures (postural change in BP measures and cfPWV) with HMOD in 3,495 participants (mean age 47 years, 53% women) using multivariable logistic and linear regression models.

Results

In multivariable-adjusted models, we did not observe significant associations of vascular measures with presence of left ventricular hypertrophy, albuminuria, covert brain infarcts, or white matter hyperintensities (Bonferroni-adjusted P-values > 0.05/20 > 0.0025). In multivariable models, greater cfPWV (est. β = 0.11 ± 0.03; P < 0.001), but not postural change in BP measures (Bonferroni-adjusted P-values > 0.05/20 > 0.0025), was associated with higher white matter free water using brain magnetic resonance imaging. In multivariable models, greater postural change in pulse pressure was associated with higher urinary albumin-creatinine ratio (est. β = 0.07 ± 0.02; P < 0.001). No other postural change in BP measure was associated with urinary albumin-creatinine ratio (Bonferroni-adjusted P-values > 0.05/20 > 0.0025). In sex-specific analyses, higher cfPWV was associated with higher urinary albumin-creatinine ratio in men (est. β: 0.11 ± 0.04; P = 0.002) but not in women (est. β: 0.03 ± 0.03; P = 0.44). We also observed marginal to strong effect modification by above vs. at/below median postural change in BP for the association of cfPWV with urinary albumin-creatinine ratio (Bonferroni-adjusted interaction P < 0.001-0.01). Vascular measures were not related to left ventricular mass index or fractional anisotropy (Bonferroni-adjusted P-values > 0.05/20 > 0.0025).

Conclusion

Baroreflex dysfunction is associated with greater subclinical kidney damage. Additionally, relations of higher aortic stiffness with greater kidney damage may be modified by associated baroreflex dysregulation.

BMAL1 drives muscle repair through control of hypoxic NAD+ regeneration in satellite cells

The process of tissue regeneration occurs in a developmentally timed manner, yet the role of circadian timing is not understood. Here, we identify a role for the adult muscle stem cell (MuSC)-autonomous clock in the control of muscle regeneration following acute ischemic injury. We observed greater muscle repair capacity following injury during the active/wake period as compared with the inactive/rest period in mice, and loss of Bmal1 within MuSCs leads to impaired muscle regeneration. We demonstrate that Bmal1 loss in MuSCs leads to reduced activated MuSC number at day 3 postinjury, indicating a failure to properly expand the myogenic precursor pool. In cultured primary myoblasts, we observed that loss of Bmal1 impairs cell proliferation in hypoxia (a condition that occurs in the first 1-3 d following tissue injury in vivo), as well as subsequent myofiber differentiation. Loss of Bmal1 in both cultured myoblasts and in vivo activated MuSCs leads to reduced glycolysis and premature activation of prodifferentiation gene transcription and epigenetic remodeling. Finally, hypoxic cell proliferation and myofiber formation in Bmal1-deficient myoblasts are restored by increasing cytosolic NAD+ Together, we identify the MuSC clock as a pivotal regulator of oxygen-dependent myoblast cell fate and muscle repair through the control of the NAD+-driven response to injury.

Applications of single-cell genomics and computational strategies to study common disease and population-level variation

The advent and rapid development of single-cell technologies have made it possible to study cellular heterogeneity at an unprecedented resolution and scale. Cellular heterogeneity underlies phenotypic differences among individuals, and studying cellular heterogeneity is an important step toward our understanding of the disease molecular mechanism. Single-cell technologies offer opportunities to characterize cellular heterogeneity from different angles, but how to link cellular heterogeneity with disease phenotypes requires careful computational analysis. In this article, we will review the current applications of single-cell methods in human disease studies and describe what we have learned so far from existing studies about human genetic variation. As single-cell technologies are becoming widely applicable in human disease studies, population-level studies have become a reality. We will describe how we should go about pursuing and designing these studies, particularly how to select study subjects, how to determine the number of cells to sequence per subject, and the needed sequencing depth per cell. We also discuss computational strategies for the analysis of single-cell data and describe how single-cell data can be integrated with bulk tissue data and data generated from genome-wide association studies. Finally, we point out open problems and future research directions.

Mortality and ventilatory effects of central serotonin deficiency during postnatal development depend on age but not sex

Serotonin (5-HT) influences brain development and has predominantly excitatory neuromodulatory effects on the neural respiratory control circuitry. Infants that succumb to sudden infant death syndrome (SIDS) have reduced brainstem 5-HT levels and Tryptophan hydroxylase 2 (Tph2). Furthermore, there are age- and sex-dependent risk factors associated with SIDS. Here we utilized our established Dark Agouti transgenic rat lacking central serotonin KO to test the hypotheses that CNS 5-HT deficiency leads to: (1) high mortality in a sex-independent manner, (2) age-dependent alterations in other CNS aminergic systems, and (3) age-dependent impairment of chemoreflexes during post-natal development. KO rat pups showed high neonatal mortality but not in a sex-dependent manner and did not show altered hypoxic or hypercapnic ventilatory chemoreflexes. However, KO rat pups had increased apnea-related metrics during a specific developmental age (P12-16), which were preceded by transient increases in dopaminergic system activity (P7-8). These results support and extend the concept that 5-HT per se is a critical factor in supporting respiratory control during post-natal development.

Obesogenic home food availability, diet, and BMI in Pakistani and White toddlers

Individuals of South Asian ethnicity have an increased risk for obesity and related diseases. Foods available in the home during the first 1000 days (conception to 24 months old) are an important determinant of diet, yet no study has examined the association of early-life home food availability (HFA) with later diet and obesity risk in South Asian households. We examined whether obesogenic HFA at 18 months of age is associated with dietary intake and body mass index (BMI) at 36 months of age in low-income Pakistani and White households in the United Kingdom. In this prospective birth cohort study (Born in Bradford 1000), follow-up assessments occurred at 18 (n = 1032) and 36 (n = 986) months of age. Variety and quantity of snack foods and sugar-sweetened beverages (SSBs) in the home and consumed were measured using the HFA Inventory Checklist and food frequency questionnaires, respectively. BMI was calculated using measured length/height and weight. Multinomial logistic regression models examined associations between HFA and tertiles of dietary intake, and multivariable linear regression models assessed associations between HFA and BMI. Pakistani households had a greater variety and quantity of snack foods and SSBs available compared with White households. Variety and quantity of snack foods and SSBs in the home at 18 months were positively associated with children's intake of these items at 36 months, but associations between HFA and BMI were null. Reducing obesogenic HFA during the first 1000 days may promote the development of more healthful diets, though this may not be associated with lower obesity risk during toddlerhood.

Tissue-specific differences in HIV DNA levels and mechanisms that govern HIV transcription in blood, gut, genital tract and liver in ART-treated women

INTRODUCTION

Sex-specific differences affect multiple aspects of HIV infection, yet few studies have quantified HIV levels in tissues from women. Since an HIV functional cure will likely require a major reduction of infected cells from most tissues, we measured total and intact HIV DNA and the HIV transcription profile in blood, gut, genital tract and liver from HIV-positive antiretroviral therapy (ART) -treated women.

METHODS

Peripheral blood mononuclear cells (PBMC) and biopsies from the gastrointestinal (ileum, colon, rectosigmoid +/- liver) and genital (ectocervix, endocervix and endometrium) tracts were collected from 6 ART-treated (HIV RNA < 200 copies/mL) women. HIV DNA (total and intact) and levels of read-through, initiated (total), 5'elongated, polyadenylated and multiply spliced HIV transcripts were measured by droplet digital PCR. Immunophenotyping of cells was performed using Cytometry by time of flight (CyTOF).

RESULTS

We detected total HIV DNA in all tissues and intact HIV DNA in blood, ileum, colon, rectosigmoid and ectocervix. Initiated HIV transcripts per provirus were higher in PBMC and endometrium than in ileum, colon, rectosigmoid, ectocervix or endocervix, and higher in the rectum than either ileum or colon. 5'Elongated HIV transcripts per provirus were comparable in PBMC and endometrium, but higher than in gut or cervical samples. Polyadenylated and multiply spliced HIV transcripts were detected in PBMC (6/6 and 3/6 individuals respectively), but rarely in the tissues.

CONCLUSIONS

These results suggest tissue-specific differences in the mechanisms that govern HIV expression, with lower HIV transcription in most tissues than blood. Therapies aimed at disrupting latency, such as latency-reversing or latency-silencing agents, will be required to penetrate into multiple tissues and target different blocks to HIV transcription.

Food insecurity and frailty among women with and without HIV in the United States: a cross-sectional analysis

INTRODUCTION

Frailty is frequently observed among people with HIV, and food insecurity is associated with frailty in the general population. Evidence is scarce on the associations between food insecurity and frailty among women with HIV who may be particularly vulnerable to the impacts of food insecurity. The goal of this study was to assess associations between food insecurity and frailty among women with and without HIV.

METHODS

There were 1265 participants from the Women's Interagency HIV Study who participated in frailty assessments in 2017. Frailty was measured using the Fried Frailty Phenotype, and women were subsequently categorized as robust, pre-frail or frail. Food insecurity was assessed using the U.S. Household Food Security Survey Module, with women categorized as having high, marginal, low or very low food security. Multinomial logistic regression models were conducted to examine cross-sectional associations between food insecurity and frailty while adjusting for socio-demographic, behavioural and HIV status covariates.

RESULTS AND DISCUSSION

Approximately one-third (31.9%) of the women had marginal, low or very low food security, and the proportions of women who met the criteria for frailty or pre-frailty were 55.6% and 12.4% respectively. In the adjusted model, the relative risk ratio (RRR) of frailty for women with very low food security versus women with high food security was 3.37 (95% CI [1.38 to 8.24], p < 0.01); the corresponding RRR of pre-frailty was 3.63 (95% CI [1.76 to 7.51], p < 0.001). Higher annual household income was associated with lower RRRs of frailty or pre-frailty (p < 0.01). Similarly, older age was associated with more frequent frailty (RRR=1.06, 95% CI [1.03 to 1.09], p < 0.001). HIV serostatus was not significantly associated with either pre-frailty (RRR=0.97, 95% CI [0.71 to 1.31]) or frailty (RRR=0.75, 95% CI [0.48 to 1.16]).

CONCLUSIONS

Very low food security was associated with more frequent frailty and pre-frailty among women with and without for HIV. HIV serostatus was not associated with frailty.

Sex differences in congestive markers in patients hospitalized for acute heart failure

AIMS

We sought to examine sex differences in congestion in patients hospitalized for acute heart failure (AHF). Understanding congestive patterns in women and men with AHF may provide insights into sex differences in the presentation and prognosis of AHF patients.

METHODS AND RESULTS

In a prospective, two-site study in adults hospitalized for AHF, four-zone lung ultrasound (LUS) was performed at the time of echocardiography at baseline (LUS1) and, in a subset, pre-discharge (LUS2). B-lines on LUS and echocardiographic images were analysed offline, blinded to clinical information and outcomes. Among 349 patients with LUS1 data (median age 74, 59% male, and 87% White), women had higher left ventricular ejection fraction (mean 43% vs. 36%, P < 0.001), higher tricuspid annular plane systolic excursion (mean 17 vs. 15 mm, P = 0.021), and higher measures of filling pressures (median E/e' 20 vs. 16, P < 0.001). B-line number on LUS1 (median 6 vs. 6, P = 0.69) and admission N-terminal pro-B-type natriuretic peptide levels (median 3932 vs. 3483 pg/mL, P = 0.77) were similar in women and men. In 121 patients with both LUS1 and LUS2 data, there was a similar and significant decrease in B-lines from baseline to discharge in both women and men. The risk of the composite 90 day outcome increased with higher B-line number on four-zone LUS2: unadjusted hazard ratio for each B-line tertile was 1.86 (95% confidence interval 1.08-3.20, P = 0.025) in women and 1.65 (95% confidence interval 1.03-2.64, P = 0.037) in men (interaction P = 0.72).

CONCLUSIONS

Among patients with AHF, echocardiographic markers differed between women and men at baseline, whereas B-line number on LUS did not. The dynamic changes in B-lines during a hospitalization for AHF were similar in women and men.

Mechanisms of phase-3 early afterdepolarizations and triggered activities in ventricular myocyte models

Early afterdepolarizations (EADs) are abnormal depolarizations during the repolarizing phase of the action potential, which are associated with cardiac arrhythmogenesis. EADs are classified into phase-2 and phase-3 EADs. Phase-2 EADs occur during phase 2 of the action potential, with takeoff potentials typically above -40 mV. Phase-3 EADs occur during phase 3 of the action potential, with takeoff potential between -70 and -50 mV. Since the amplitude of phase-3 EADs can be as large as that of a regular action potential, they are also called triggered activities (TAs). This also makes phase-3 EADs and TAs much more arrhythmogenic than phase-2 EADs since they can propagate easily in tissue. Although phase-2 EADs have been widely observed, phase-3 EADs and TAs have been rarely demonstrated in isolated ventricular myocytes. Here we carry out computer simulations of three widely used ventricular action potential models to investigate the mechanisms of phase-3 EADs and TAs. We show that when the T-type Ca2+ current (ICa,T ) is absent (e.g., in normal ventricular myocytes), besides the requirement of increasing inward currents and reducing outward currents as for phase-2 EADs, the occurrence of phase-3 EADs and TAs requires a substantially large increase of the L-type Ca2+ current and the slow component of the delayed rectifier K+ current. The presence of ICa,T (e.g., in neonatal and failing ventricular myocytes) can greatly reduce the thresholds of these two currents for phase-3 EADs and TAs. This implies that ICa,T may play an important role in arrhythmogenesis in cardiac diseases.

Feasibility/acceptability of an acceptance-based therapy intervention for diverse adolescent girls with overweight/obesity

BACKGROUND

Behavioral obesity interventions using an acceptance-based therapy (ABT) approach have demonstrated efficacy for adults, yet feasibility and acceptability of tailoring an ABT intervention for adolescents remains unknown.

OBJECTIVE

This study assessed the feasibility and acceptability of an ABT healthy lifestyle intervention among diverse adolescent cisgender girls with overweight/obesity (OW/OB).

METHODS

Adolescent cisgender girls aged 14-19 with a BMI of ≥85th percentile-for-sex-and-age were recruited for participation in a single-arm feasibility study. The primary outcomes were recruitment and retention while the secondary outcome was change in BMI Z-score over the 6-month intervention. Exploratory outcomes included obesity-related factors, health-related behaviors, and psychological factors.

RESULTS

Recruitment goals were achieved; 13 adolescents (>60% racial/ethnic minorities) participated in the intervention, and 11 completed the intervention (85% retention). In completers (n = 11), a mean decrease in BMI Z-score of -0.15 (SD = 0.34, Cohen's d = -0.44) was observed. Improvements were also noted for change in percentage of 95th percentile (d = -0.35), percent body fat (d = -0.35), quality of life (d = 0.71), psychological flexibility (d = -0.86), and depression (d = -0.86).

CONCLUSIONS

These preliminary findings suggest an ABT healthy lifestyle intervention tailored for adolescent cisgender girls with OW/OB may be an acceptable treatment that could lead to improvements in BMI Z-score, obesity-related measures, and psychological outcomes.

Longitudinal profiling of circulating miRNA during cardiac allograft rejection: a proof-of-concept study

AIMS

Allograft rejection following heart transplantation (HTx) is a serious complication even in the era of modern immunosuppressive regimens and causes up to a third of early deaths after HTx. Allograft rejection is mediated by a cascade of immune mechanisms leading to acute cellular rejection (ACR) and/or antibody-mediated rejection (AMR). The gold standard for monitoring allograft rejection is invasive endomyocardial biopsy that exposes patients to complications. Little is known about the potential of circulating miRNAs as biomarkers to detect cardiac allograft rejection. We here present a systematic analysis of circulating miRNAs as biomarkers and predictors for allograft rejection after HTx using next-generation small RNA sequencing.

METHODS AND RESULTS

We used next-generation small RNA sequencing to investigate circulating miRNAs among HTx recipients (10 healthy controls, 10 heart failure patients, 13 ACR, and 10 AMR). MiRNA profiling was performed at different time points before, during, and after resolution of the rejection episode. We found three miRNAs with significantly increased serum levels in patients with biopsy-proven cardiac rejection when compared with patients without rejection: hsa-miR-139-5p, hsa-miR-151a-5p, and hsa-miR-186-5p. We identified miRNAs that may serve as potential predictors for the subsequent development of ACR: hsa-miR-29c-3p (ACR) and hsa-miR-486-5p (AMR). Overall, hsa-miR-486-5p was most strongly associated with acute rejection episodes.

CONCLUSIONS

Monitoring cardiac allograft rejection using circulating miRNAs might represent an alternative strategy to invasive endomyocardial biopsy.

Trends in demographic and clinical characteristics and initiation of antiretroviral therapy among adult patients enrolling in HIV care in the Central Africa International epidemiology Database to Evaluate AIDS (CA-IeDEA) 2004 to 2018

INTRODUCTION

The Central Africa International epidemiology Database to Evaluate AIDS (CA-IeDEA) is an open observational cohort study investigating impact, progression and long-term outcomes of HIV/AIDS among people living with HIV (PLWH) in Burundi, Cameroon, Democratic Republic of Congo (DRC), Republic of Congo (ROC) and Rwanda. We describe trends in demographic, clinical and immunological characteristics as well as antiretroviral therapy (ART) use of patients aged > 15 years entering into HIV care in the participating CA-IeDEA site.

METHODS

Information on sociodemographic characteristics, height, weight, body mass index (BMI), CD4 cell count, WHO staging and ART status at entry into care from 2004 through 2018 were extracted from clinic records of patients aged > 15 years enrolling in HIV care at participating clinics in Burundi, Cameroon, DRC, ROC and Rwanda. We assessed trends in patient characteristics at enrolment in HIV care including ART initiation within the first 30 days after enrolment in care and calculated proportions, means and medians (interquartile ranges) for the main variables of interest.

RESULTS

Among 69,176 patients in the CA-IeDEA cohort, 39% were from Rwanda, 24% from ROC, 18% from Cameroon, 14% from Burundi and 5% from DRC. More women (66%) than men enrolled in care and subsequently initiated ART. Women were also younger than men (32 vs. 38 years, P < 0.001) at enrolment and at ART initiation. Trends over time show increases in median CD4 cell count at enrolment from 190 cells/µL in 2004 to 334 cells/µL in 2018 at enrolment. Among those with complete data on CD4 counts (60%), women had a higher median CD4 cell count at care entry than men (229 vs. 249 cells/µL, P < 0.001). Trends in the proportion of patients using ART within 30 days of enrolment at the participating site show an increase from 16% in 2004 to 75% in 2018.

CONCLUSIONS

Trends from 2004 to 2018 in the characteristics of patients participating in the CA-IeDEA cohort highlight improvements at entry into care and subsequent ART initiation including after the implementation of Treat All guidelines in the participating sites.

Ambulatory Care Fragmentation and Incident Stroke

Background More fragmented ambulatory care (ie, care spread across many providers without a dominant provider) has been associated with excess emergency department and inpatient care. We sought to determine whether more fragmented ambulatory care is associated with an increase in the hazard of incident stroke, overall and stratified by health status and by race. Methods and Results We conducted a secondary analysis of data from the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study (2003-2016), including participants aged ≥65 years who had linked Medicare fee-for-service claims and no history of stroke (N=12 510). We measured fragmentation of care with the reversed Bice-Boxerman index. We used Poisson models to determine the association between fragmentation and adjudicated incident stroke. The average age of participants was 70.5 years; 53% were women, 32% were Black participants, and 16% were participants with fair or poor health. Overall, the adjusted rate of incident stroke was similar for high versus low fragmentation (8.2 versus 8.1 per 1000 person-years, respectively; P=0.89). Among participants with fair or poor self-rated health, having high versus low fragmentation was associated with a trend toward a higher adjusted rate of incident strokes (14.8 versus 10.4 per 1000 person-years, respectively; P=0.067). Among Black participants with fair or poor self-rated health, having high versus low fragmentation was associated with a higher adjusted rate of strokes (19.3 versus 10.3 per 1000 person-years, respectively; P=0.02). Conclusions Highly fragmented ambulatory care is independently associated with incident stroke among Black individuals with fair or poor health.

Epidemiology of Heart Failure Stages in Middle-Aged Black People in the Community: Prevalence and Prognosis in the Atherosclerosis Risk in Communities Study

Background Black individuals have a higher burden of risk factors for heart failure (HF) and subclinical left ventricular remodeling. Methods and Results We evaluated 1871 Black participants in the Atherosclerosis Risk in Communities Study cohort who attended a routine examination (1993-1996, median age 58 years) when they underwent echocardiography. We estimated the prevalences of 4 HF stages: (1) Stage 0: no risk factors; (2) Stage A: presence of HF risk factors (hypertension, diabetes mellitus, obesity, smoking, dyslipidemia, coronary artery disease without clinical myocardial infarction), no cardiac structural/functional abnormality; (3) Stage B: presence of prior myocardial infarction, systolic dysfunction, left ventricular hypertrophy, regional wall motion abnormality, or left ventricular enlargement; and (4) Stage C/D: prevalent HF. We assessed the incidence of clinical HF, atherosclerotic cardiovascular disease events, and all-cause mortality on follow-up according to HF stage. The prevalence of HF Stages 0, A, B, and C/D were 3.8%, 20.6%, 67.0%, and 8.6%, respectively, at baseline. On follow-up (median 19.0 years), 309 participants developed overt HF, 390 incurred new-onset cardiovascular disease events, and 651 individuals died. Incidence rates per 1000 person-years for overt HF, cardiovascular disease events, and death, respectively, were Stage 0, 2.4, 0.8, and 7.6; Stage A, 7.4, 9.7, and 13.5; Stage B 13.6, 15.9, and 22.0. Stage B HF was associated with a 1.5- to 2-fold increased adjusted risk of HF, cardiovascular disease events and death compared with Stages 0/A. Conclusions In our large community-based sample of Black individuals, we observed a strikingly high prevalence of Stage B HF in middle age that was a marker of high cardiovascular morbidity and mortality.

Cell-Laden Multiple-Step and Reversible 4D Hydrogel Actuators to Mimic Dynamic Tissue Morphogenesis

Shape-morphing hydrogels bear promising prospects as soft actuators and for robotics. However, they are mostly restricted to applications in the abiotic domain due to the harsh physicochemical conditions typically necessary to induce shape morphing. Here, multilayer hydrogel actuator systems are developed using biocompatible and photocrosslinkable oxidized, methacrylated alginate and methacrylated gelatin that permit encapsulation and maintenance of living cells within the hydrogel actuators and implement programmed and controlled actuations with multiple shape changes. The hydrogel actuators encapsulating cells enable defined self-folding and/or user-regulated, on-demand-folding into specific 3D architectures under physiological conditions, with the capability to partially bioemulate complex developmental processes such as branching morphogenesis. The hydrogel actuator systems can be utilized as novel platforms for investigating the effect of programmed multiple-step and reversible shape morphing on cellular behaviors in 3D extracellular matrix and the role of recapitulating developmental and healing morphogenic processes on promoting new complex tissue formation.

Therapeutic Delivery of Pip4k2c-Modified mRNA Attenuates Cardiac Hypertrophy and Fibrosis in the Failing Heart

Heart failure (HF) remains a major cause of morbidity and mortality worldwide. One of the risk factors for HF is cardiac hypertrophy (CH), which is frequently accompanied by cardiac fibrosis (CF). CH and CF are controlled by master regulators mTORC1 and TGF-β, respectively. Type-2-phosphatidylinositol-5-phosphate-4-kinase-gamma (Pip4k2c) is a known mTORC1 regulator. It is shown that Pip4k2c is significantly downregulated in the hearts of CH and HF patients as compared to non-injured hearts. The role of Pip4k2c in the heart during development and disease is unknown. It is shown that deleting Pip4k2c does not affect normal embryonic cardiac development; however, three weeks after TAC, adult Pip4k2c-/- mice has higher rates of CH, CF, and sudden death than wild-type mice. In a gain-of-function study using a TAC mouse model, Pip4k2c is transiently upregulated using a modified mRNA (modRNA) gene delivery platform, which significantly improve heart function, reverse CH and CF, and lead to increased survival. Mechanistically, it is shown that Pip4k2c inhibits TGFβ1 via its N-terminal motif, Pip5k1α, phospho-AKT 1/2/3, and phospho-Smad3. In sum, loss-and-gain-of-function studies in a TAC mouse model are used to identify Pip4k2c as a potential therapeutic target for CF, CH, and HF, for which modRNA is a highly translatable gene therapy approach.

Anti-factor Xa activity assays of direct-acting oral anticoagulants during clinical care: An observational study

BACKGROUND

Direct-acting oral anticoagulants (DOACs) are increasingly used to prevent and treat thromboembolism. Although measurement of DOAC concentrations is not currently recommended as part of routine patient care, measurement of DOAC concentrations with anti-factor Xa activity assays have recently become clinically available.

OBJECTIVES

Our goal was to determine the clinical conditions under which DOAC concentration measurements are requested.

MATERIALS AND METHODS

Retrospective electronic medical record analysis of indications for DOAC concentration measurements by anti-factor Xa activity assay at a single academic medical center from July 2015 through April 2020.

RESULTS AND CONCLUSIONS

Ninety-one DOAC concentration measurements were made in 69 patients: 28 received apixaban and 41 received rivaroxaban. The most frequent indication for concentration measurement was drug exposure assessment (38/69; 55%) in patients with potentially altered pharmacokinetics (altered absorption or clearance), recurrent thromboembolic events, or possible medication nonadherence. Fourteen of 69 patients had repeated measurements during preoperative evaluation before emergent surgery; one-third of those with detectable levels upon presentation had repeated measurements until concentrations were undetectable. Levels were undetectable in 4 of 4 patients scheduled for elective surgery. Eleven of 69 patients had DOAC measurements in the setting of major bleeding; 5 of these 11 received a specific DOAC reversal agent. While most of the observed indications appear in clinical guidelines, altered absorption does not. Overall, clinicians are requesting DOAC concentration measurements to evaluate drug exposure in patients with conditions that might alter the absorption or clearance of the DOAC, to evaluate surgical bleeding risk, and in the setting of major bleeding.

Cardiac-Specific Deletion of Orai3 Leads to Severe Dilated Cardiomyopathy and Heart Failure in Mice

Background Orai3 is a mammalian-specific member of the Orai family (Orai1‒3) and a component of the store-operated Ca2+ entry channels. There is little understanding of the role of Orai channels in cardiomyocytes, and its role in cardiac function remains unexplored. Thus, we developed mice lacking Orai1 and Orai3 to address their role in cardiac homeostasis. Methods and Results We generated constitutive and inducible cardiomyocyte-specific Orai3 knockout (Orai3cKO) mice. Constitutive Orai3-loss led to ventricular dysfunction progressing to dilated cardiomyopathy and heart failure. Orai3cKO mice subjected to pressure overload developed a fulminant dilated cardiomyopathy with rapid heart failure onset, characterized by interstitial fibrosis and apoptosis. Ultrastructural analysis of Orai3-deficient cardiomyocytes showed abnormal M- and Z-line morphology. The greater density of condensed mitochondria in Orai3-deficient cardiomyocytes was associated with the upregulation of DRP1 (dynamin-related protein 1). Cardiomyocytes isolated from Orai3cKO mice exhibited profoundly altered myocardial Ca2+ cycling and changes in the expression of critical proteins involved in the Ca2+ clearance mechanisms. Upregulation of TRPC6 (transient receptor potential canonical type 6) channels was associated with upregulation of the RCAN1 (regulator of calcineurin 1), indicating the activation of the calcineurin signaling pathway in Orai3cKO mice. A more dramatic cardiac phenotype emerged when Orai3 was removed in adult mice using a tamoxifen-inducible Orai3cKO mouse. The removal of Orai1 from adult cardiomyocytes did not change the phenotype of tamoxifen-inducible Orai3cKO mice. Conclusions Our results identify a critical role for Orai3 in the heart. We provide evidence that Orai3-mediated Ca2+ signaling is required for maintaining sarcomere integrity and proper mitochondrial function in adult mammalian cardiomyocytes.

Sex-related differences in cognitive trajectories in older individuals with type 2 diabetes and overweight or obesity

INTRODUCTION

It is unknown whether rates of cognitive decline differ between older women and men with type 2 diabetes (T2D) and overweight or obesity.

METHODS

Two to four cognitive assessments were obtained across up to 10 years from 2799 adults (mean age 68 years; 62% women) with T2D who had been enrolled in a clinical trial of weight loss intervention. Sex-related differences in means and rates of decline of cognitive scores were assessed.

RESULTS

Women outperformed men in verbal learning and processing speed (P < 0.001), but not executive function (P = 0.22). The rates of decline over time for women and men were similar (P ≥  0.10); however women, but not men, with apolipoprotein E (APOE) ε4 alleles had steeper declines in verbal learning (P = 0.02) and processing speed (P = 0.007) than those without these alleles.

DISCUSSION

Cognitive advantages for women with T2D and overweight/obesity over men are preserved as they age; however, these are eroded by the APOE ε4 genotype.

Estimated Impact of Achieving Optimal Cardiovascular Health Among US Adults on Cardiovascular Disease Events

Background Better cardiovascular health (CVH) scores are associated with lower risk of cardiovascular disease (CVD). However, estimates of the potential population-level impact of improving CVH on US CVD event rates are not currently available. Methods and Results Using data from the National Health and Nutrition Examination Survey 2011 to 2016 (n=11 696), we estimated the proportions of US adults in CVH groups. Levels of 7 American Heart Association CVH metrics were scored as ideal (2 points), intermediate (1 point), or poor (0 points), and summed to define overall CVH (low, 0-8 points; moderate, 9-11 points; or high, 12-14 points). Using individual-level data from 7 US community-based cohort studies (n=30 447), we estimated annual incidence rates of major CVD events by levels of CVH. Using the combined data sources, we estimated population attributable fractions of CVD and the number of CVD events that could be prevented annually if all US adults achieved high CVH. High CVH was identified in 7.3% (95% CI, 6.3%-8.3%) of US adults. We estimated that 70.0% (95% CI, 56.5%-79.9%) of CVD events were attributable to low and moderate CVH. If all US adults attained high CVH, we estimated that 2.0 (95% CI, 1.6-2.3) million CVD events could be prevented annually. If all US adults with low CVH attained moderate CVH, we estimated that 1.2 (95% CI, 1.0-1.4) million CVD events could be prevented annually. Conclusions The potential benefits of achieving high CVH in all US adults are considerable, and even a partial improvement in CVH scores would be highly beneficial.

Strategies to manage weight during the holiday season among US adults: A descriptive study from the National Weight Control Registry

BACKGROUND

Holidays are challenging for weight control and are consistently associated with weight gain. Managing holiday weight gain may be especially difficult for individuals with higher body weight or a history of overweight/obesity. The current study evaluated how individuals with a history of successful weight loss plan for the holiday season and how the use of weight control strategies was associated with weight change.

METHODS

A subgroup of participants in the National Weight Control Registry (NWCR) were asked to complete a survey before (November) and after the holidays (January). At pre-holiday, participants reported height, weight, and weight goals for the holiday season (lose, maintain, minimize gains, or gain), and selected the top three weight control strategies they planned to use (from a list of 18). Post-holiday, participants reported weight and how often (frequently, infrequently, or not at all) they used each of the 18 strategies throughout the holidays.

RESULTS

Individuals who completed both surveys were included in the analysis (n = 683; 69% female, 93% white, 54.6 years [SD: 13.2], 26.9 kg/m2 [SD: 5.5]). Pre-holiday, 64% of participants were currently trying to lose weight. Only 35% of the sample wanted to continue losing weight during the holiday season. The most common strategies individuals planned to use during the holiday season were evidence based (maintaining exercise, monitoring portions, tracking foods, and self-weighing). Participants gained 0.66 kg (SD: 1.85) from pre- to post-holiday and reported using an average of 12/18 strategies. A greater number of strategies were associated with less weight gain (F[1, 670] = 4.28, p = 0.04). Daily self-weighing (p = 0.03) and prioritizing food choices (p = 0.02) were individually associated with less weight gain.

DISCUSSION

Participants in the NWCR entered the holiday season with a variety of goals for their weight and used many different strategies to control their weight. Having a wider range of strategies may be helpful to navigate the challenges to weight control during the holidays.

High-protein vs. standard-protein diets in overweight and obese patients with heart failure and diabetes mellitus: findings of the Pro-HEART trial

AIMS

The intermediate-term effects of dietary protein on cardiometabolic risk factors in overweight and obese patients with heart failure and diabetes mellitus are unknown. We compared the effect of two calorie-restricted diets on cardiometabolic risk factors in this population.

METHODS AND RESULTS

In this randomized controlled study, 76 overweight and obese (mean weight, 107.8 ± 20.8 kg) patients aged 57.7 ± 9.7 years, 72.4% male, were randomized to a high-protein (30% protein, 40% carbohydrates, and 30% fat) or standard-protein diet (15% protein, 55% carbohydrates, and 30% fat) for 3 months. Reductions in weight and cardiometabolic risks were evaluated at 3 months. Both diets were equally effective in reducing weight (3.6 vs. 2.9 kg) and waist circumference (1.9 vs. 1.3 cm), but the high-protein diet decreased to a greater extent glycosylated haemoglobin levels (0.7% vs. 0.1%, P = 0.002), cholesterol (16.8 vs. 0.9 mg/dL, P = 0.031), and triglyceride (25.7 vs. 5.7 mg/dL, P = 0.032), when compared with the standard-protein diet. The high-protein diet also significantly improved both systolic and diastolic blood pressure than the standard-protein diet (P < 0.001 and P = 0.040, respectively).

CONCLUSIONS

Both energy-restricted diets reduced weight and visceral fat. However, the high-protein diet resulted in greater reductions in cardiometabolic risks relative to a standard-protein diet. These results suggest that a high-protein diet may be more effective in reducing cardiometabolic risk in this population, but further trials of longer duration are needed.

PAR1 regulation of CXCL1 expression and neutrophil recruitment to the lung in mice infected with influenza A virus

BACKGROUND

Protease-activated receptor 1 (PAR1) is expressed in various immune cells and in the lung. We showed that PAR1 plays a role in Coxsackievirus B3 infection by enhancing toll-like receptor 3-dependent interferon- β expression in cardiac fibroblasts.

OBJECTIVES

We investigated the role of PAR1 in a mouse model of influenza A virus (IAV) infection.

METHODS

We used mice with either a global deficiency of PAR1, cell type-specific deficiencies of PAR1, or mutation of PAR1 at the R41 or R46 cleavage sites.

RESULTS

PAR1-deficient mice had increased CXCL1 expression in the lung, increased neutrophil recruitment, increased protein levels in the bronchoalveolar lavage fluid, and increased mortality after IAV infection compared with control mice infected with IAV. Results from mice with cell type-specific deletion of PAR1 indicated that PAR1 expression by hematopoietic cells suppressed CXCL1 expression, whereas PAR1 expression by endothelial cells enhanced CXCL1 expression in response to IAV infection. PAR1 activation also enhanced polyinosinic:polycytodylic acid induction of interleukin-8 in a human endothelial cell line. Mutation of the R46 cleavage site of PAR1 was associated with increased CXCL1 expression in the lung in response to IAV infection, which suggested that R46 signaling suppresses CXCL1 expression.

CONCLUSIONS

These results indicate that PAR1 expression by different cell types and activation by different proteases modulates the immune response during IAV infection.

Characteristics of Populations Excluded From Clinical Trials Supporting Intensive Blood Pressure Control Guidelines

Background Only one third of patients recommended intensified treatment by the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guideline for high blood pressure would have been eligible for the clinical trials on which recommendations were largely based. We sought to identify characteristics of adults who would have been trial-ineligible in order to inform clinical practice and research priorities. Methods and Results We examined the proportion of adults diagnosed with hypertension who met trial inclusion and exclusion criteria, stratified by age, diabetes mellitus status, and guideline recommendations in a cross-sectional study of the National Health and Nutrition Examination Survey, 2013-2016. Of the 107.7 million adults (95% CI, 99.3-116.0 million) classified as having hypertension by the ACC/AHA guideline, 23.1% (95% CI, 20.8%-25.5%) were below the target blood pressure of 130/80 mm Hg, 22.2% (95% CI, 20.1%-24.4%) would be recommended nonpharmacologic treatment, and 54.6% (95% CI, 52.5%-56.7%) would be recommended additional pharmacotherapy. Only 20.6% (95% CI, 18.8%-22.4%) of adults with hypertension would be trial-eligible. The majority of adults <50 years were excluded because of low cardiovascular risk and lack of access to primary care. The majority of adults aged ≥70 years were excluded because of multimorbidity and limited life expectancy. Reasons for trial exclusion were similar for patients with and without diabetes mellitus. Conclusions Intensive blood pressure treatment trials were not representative of many younger adults with low cardiovascular risk and older adults with multimorbidity who are now recommended more intensive blood pressure goals.

Slow wave sleep in naps supports episodic memories in early childhood

Naps have been shown to benefit visuospatial learning in early childhood. This benefit has been associated with sleep spindles during the nap. However, whether young children's naps and their accompanying physiology benefit other forms of declarative learning is unknown. Using a novel storybook task, we found performance in children (N = 22, mean age = 51.23 months) was better following a nap compared to performance following an equivalent interval spent awake. Moreover, performance remained better the following day if a nap followed learning. Change in post-nap performance was positively associated with the amount of time spent in slow wave sleep during the nap. This suggests that slow wave sleep in naps may support episodic memory consolidation in early childhood. Taken in conjunction with prior work, these results suggest that multiple features of brain physiology during naps may contribute to declarative memory processing in early childhood.

Isomerization of trans-3-methylglutaconic acid

3-Methylglutaconic (3MGC) aciduria is a common phenotypic feature of a growing number of inborn errors of metabolism. "Primary" 3MGC aciduria is caused by deficiencies in leucine pathway enzymes while "secondary" 3MGC aciduria results from inborn errors of metabolism that impact mitochondrial energy production. The metabolic precursor of 3MGC acid is trans-3MGC CoA, an intermediate in the leucine catabolism pathway. Gas chromatography-mass spectrometry (GC-MS) analysis of commercially available trans-3MGC acid yielded a mixture of cis and trans isomers while 1H-NMR spectroscopy of trans-3MGC acid at 25°C provided no evidence for the cis isomer. When trans-3MGC acid was incubated under conditions used for sample derivatization prior to GC-MS (but with no trimethylsilane added), 1H-NMR spectroscopy provided evidence of trans to cis isomerization. Incubation of trans-3MGC acid at 37°C resulted in time-dependent isomerization to cis-3MGC acid. Cis-3MGC acid behaved in a similar manner except that, under identical incubation conditions, less isomerization occurred. In agreement with these experimental results, molecular modeling studies provided evidence that the energy minimized structure of cis-3MGC acid is 4 kJ/mol more stable than that for trans-3MGC acid. Once generated in vivo, trans-3MGC acid is proposed to isomerize via a mechanism involving π electron delocalization with formation of a resonance structure that permits bond rotation. The data presented are consistent with the occurrence of both diastereomers in urine samples of subjects with 3MGC aciduria.

APOE alleles' association with cognitive function differs across Hispanic/Latino groups and genetic ancestry in the study of Latinos-investigation of neurocognitive aging (HCHS/SOL)

INTRODUCTION

Apolipoprotein E (APOE) alleles are associated with cognitive decline, mild cognitive impairment (MCI), and Alzheimer's disease in Whites, but have weaker and inconsistent effects reported in Latinos. We hypothesized that this heterogeneity is due to ancestry-specific genetic effects.

METHODS

We investigated the associations of the APOE alleles with significant cognitive decline and MCI in 4183 Latinos, stratified by six Latino backgrounds, and explored whether the proportion of continental genetic ancestry (European, African, and Amerindian) modifies these associations.

RESULTS

APOE ε4 was associated with an increased risk of significant cognitive decline (odds ratio [OR] = 1.15, P-value = 0.03), with the strongest association in Cubans (OR = 1.46, P-value = 0.007). APOE-ε2 was associated with decreased risk of MCI (OR = 0.37, P-value = 0.04) in Puerto Ricans. Amerindian genetic ancestry was found to protect from the risk conferred by APOE ε4 on significant cognitive decline.

DISCUSSION

Results suggest that APOE alleles' effects on cognitive outcomes differ across six Latino backgrounds and are modified by continental genetic ancestry.

Exploring the utility of a novel point-of-care whole blood thrombin generation assay following trauma: A pilot study

INTRODUCTION

Plasma thrombin generation kinetics as measured by the calibrated automated thrombogram (CAT) assay is a predictor of symptomatic venous thromboembolism after trauma. We hypothesized that data from a new prototype assay for measurement of thrombin generation kinetics in fresh whole blood (near patient testing of thrombin generation), will correlate with the standard CAT assay in the same patients, making it a potential tool in the future care of trauma patients.

METHODS

Patients were enrolled from June 2018 to February 2020. Within 12 hours of injury, blood samples were collected simultaneously for both assays. Variables compared and correlated between assays were lag time, peak height, time to peak, and endogenous thrombin potential. Data are presented as median with interquartile range (IQR). Spearman and Pearson correlations were estimated and tested between both assays; a P value of <0.05 was considered to be significant.

RESULTS

A total of 64 trauma patients had samples analyzed: injury severity score = 17 (IQR), 10-26], hospital length of stay = 7.5 (IQR), 2-18) days, age = 52 (IQR, 35-63) years, 71.9% male, and 42.2% of patients received a transfusion within 24 hours of injury. Thrombin generation parameters between plasma and whole blood were compared and found that all parameters of the two assays correlate in trauma patients.

CONCLUSION

In this pilot study, we have found that a novel point-of-care whole blood thrombin generation assay yields results with modest but statistically significant correlations to those of a standard plasma thrombin generation assay. This finding supports studying this device in a larger, adequately powered study.

miR-467 regulates inflammation and blood insulin and glucose

Obesity is associated with inflammation and insulin resistance (IR), but the regulation of insulin sensitivity (IS) and connections between IS and inflammation remain unclear. We investigated the role of miR-467a-5p, a miRNA induced by hyperglycaemia, in regulating inflammation and blood glucose handling. We previously demonstrated that miR-467a-5p is induced by hyperglycaemia and inhibits the production of thrombospondin-1 (TSP-1), a protein implicated in regulating inflammation. To investigate the role of miR-467 in blood glucose handling and tissue inflammation, WT C57BL/6 mice were fed chow or Western diet from 5 to 32 weeks of age and injected weekly with miR-467a-5p antagonist. Inhibiting miR-467a-5p resulted in 47% increase in macrophage infiltration and increased Il6 levels in adipose tissue, higher plasma insulin levels (98 ng/mL vs 63 ng/mL), and 17% decrease in glucose clearance without increase in weight or HDL/LDL. The antagonist effect was lost in mice on Western diet. Mice lacking TSP-1 lost some but not all of the miR-467 effects, suggesting Thbs1 (and other unknown transcripts) are targeted by miR-467 to regulate inflammation. miR-467a-5p provides a physiological feedback when blood glucose is elevated to avoid inflammation and increased blood glucose and insulin levels, which may prevent IR.

Associations of Job Strain, Stressful Life Events, and Social Strain With Coronary Heart Disease in the Women's Health Initiative Observational Study

Background

The association between psychosocial stress and coronary heart disease (CHD) may be stronger in women than men and may differ across types of stressors. In this study, we assessed associations of psychosocial stressors, including job strain, stressful life events, and social strain with the incidence of CHD in women.

Methods and Results

We used longitudinal data from 80 825 WHI‐OS (Women's Health Initiative Observational Study) participants with a mean age of 63.4 years (7.3 years) at baseline. Job strain was assessed through linkage of Standard Occupational Classification codes to the Occupational Information Network. Stressful life events and social strain were assessed via validated self‐reported questionnaires. Cox proportional hazard models were used to evaluate associations of each stressor with CHD separately and jointly. A total of 3841 (4.8%) women developed CHD during an average of 14.7 years of follow‐up. After adjustment for age, other stressors, job tenure, and socioeconomic factors, high stressful life events score was associated with a 12% increased CHD risk, and high social strain was associated with a 9% increased CHD risk. Job strain was not independently associated with CHD risk, but we observed a statistically significant interaction between job strain and social strain (P=0.04), such that among women with high social strain, passive job strain was associated with a 21% increased CHD risk.

Conclusions

High stressful life events and social strain were each associated with higher CHD risk. Job strain and social strain work synergistically to increase CHD risk.

Experiences and Beliefs of Low-Income Patients With Hypertension in Louisiana and Mississippi During the COVID-19 Pandemic

Background The coronavirus disease 2019 (COVID-19) pandemic disproportionately affects individuals with hypertension and health disparities. Methods and Results We assessed the experiences and beliefs of low-income and minority patients with hypertension during the COVID-19 pandemic. Participants (N=587) from the IMPACTS-BP (Implementation of Multifaceted Patient-Centered Treatment Strategies for Intensive Blood Pressure Control) study completed a telephone survey in May and June of 2020. Participants were 65.1% Black and 59.7% female, and 57.7% reported an income below the federal poverty level. Overall, 2.7% tested positive and 15.3% had lost a family member or friend to COVID-19. These experiences were significantly more common in Black (3.9% and 19.4%, respectively) than in non-Black participants (0.5% and 7.8%, respectively). In addition, 14.5% lost a job and 15.9% reported food shortages during the pandemic. Most participants complied with stay-at-home orders (98.3%), social distancing (97.8%), and always wearing a mask outside their home (74.6%). Participants also reported high access to needed health care (94.7%) and prescription medications (97.6%). Furthermore, 95.7% of respondents reported that they continued to take their regular dosage of antihypertensive medications. Among the 44.5% of participants receiving a healthcare appointment by telehealth, 96.6% got the help they needed, and 80.8% reported that the appointment quality was as good as or better than in-person visits. Finally, 88.9% were willing to return to their primary care clinic. Conclusions These data suggest that low-income patients, especially Black patients, were negatively impacted by COVID-19. However, most patients were able to access needed healthcare services and were willing to return to their primary care clinic for hypertension management. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03483662.

Maternal Coronary Heart Disease, Stroke, and Mortality Within 1, 3, and 5 Years of Delivery Among Women With Hypertensive Disorders of Pregnancy and Pre-Pregnancy Hypertension

Background Pre-pregnancy hypertension and hypertensive disorders of pregnancy (HDP; preeclampsia, eclampsia, gestational hypertension) are major health risks for maternal morbidity and mortality. However, it is unknown if racial/ethnic differences exist. We aimed to determine the impact of HDP and pre-pregnancy hypertension on maternal coronary heart disease, stroke, and mortality risk ≤1, 3, and 5 years post-delivery and by race/ethnicity ≤5 years. Methods and Results This retrospective cohort study included women aged 12 to 49 years with a live, singleton birth between 2004 to 2016 (n=254 491 non-Hispanic White; n=137 784 non-Hispanic Black; n=41 155 Hispanic). Birth and death certificates and International Classification of Diseases, Ninth and Tenth Revision, Clinical Modification (ICD-9-CM and ICD-10-CM) diagnosis codes in hospitalization/emergency department visit data defined HDP, pre-pregnancy hypertension, incident coronary heart disease and stroke, and all-cause mortality. During at least 1 pregnancy of the 433 430 women, 2.3% had pre-pregnancy hypertension with superimposed HDP, 15.7% had no pre-pregnancy hypertension with HDP, and 0.4% had pre-pregnancy hypertension without superimposed HDP, whereas 81.6% had neither condition. Maternal deaths from coronary heart disease, stroke, and all causes totaled 2136. Within 5 years of delivery, pre-pregnancy hypertension, and HDP were associated with all-cause mortality (hazard ratio [HR], 2.21; 95% CI, 1.61-3.03), incident coronary heart disease (HR, 3.79; 95% CI, 3.09-4.65), and incident stroke (HR, 3.10; 95% CI, 2.09-4.60). HDP alone was related to all outcomes. Race/ethnic differences were observed for non-Hispanic Black and non-Hispanic White women, respectively, in the associations of pre-pregnancy hypertension and HDP with all-cause mortality within 5 years of delivery (HR, 2.34 [95% CI, 1.58-3.47]; HR, 2.11 [95% CI, 1.23-3.65]; P interaction=0.001). Conclusions Maternal cardiovascular outcomes including mortality were increased ≤5 years post-delivery in HDP, pre-pregnancy hypertension, or pre-pregnancy hypertension with superimposed HDP. The race/ethnic interaction for all-cause mortality ≤5 years of delivery warrants further research.

Association of Psychosocial Factors With Short-Term Resting Heart Rate Variability: The Atherosclerosis Risk in Communities Study

Background Psychosocial factors predict heart disease risk, but our understanding of underlying mechanisms is limited. We sought to evaluate the physiologic correlates of psychosocial factors by measuring their relationships with heart rate variability (HRV), a measure of autonomic health, in the ARIC (Atherosclerosis Risk in Communities) study. We hypothesize that increased psychosocial stress associates with lower HRV. Methods and Results We studied 9331 participants in ARIC with short-term HRV data at visits 2 and 4. The mean (SD) age was 54.4 (5.7) years, 55% were women, and 25% were Black. Psychosocial factors included: (1) vital exhaustion (VE), (2) anger proneness, a personality trait, and (3) perceived social support. Linear models adjusted for sociodemographic and cardiovascular risk factors. Low frequency HRV (ln ms2) was significantly lower in the highest versus lowest quartiles of VE (B=-0.14, 95% CI, -0.24 to -0.05). When comparing this effect to age (B=-0.04, 95% CI, -0.05 to -0.04), the difference was equivalent to 3.8 years of accelerated aging. Perceived social support associated with lower time-domain HRV. High VE (versus low VE) also associated with greater decreases in low frequency over time, and both anger and VE associated with greater increases in resting heart rate over time. Survival analyses were performed with Cox models, and no evidence was found that HRV explains the excess risk found with high VE and low perceived social support. Conclusions Vital exhaustion, and to a lesser extent anger and social support, were associated with worse autonomic function and greater adverse changes over time.

Low-density lipoprotein receptor is required for cholesteryl ester transfer protein to regulate triglyceride metabolism in both male and female mice

Elevated triglycerides (TGs) and impaired TG clearance increase the risk of cardiovascular disease in both men and women, but molecular mechanisms remain poorly understood. Cholesteryl ester transfer protein (CETP) is a lipid shuttling protein known for its effects on high-density lipoprotein cholesterol. Although mice lack CETP, transgenic expression of CETP in mice alters TG metabolism in males and females by sex-specific mechanisms. A unifying mechanism explaining how CETP alters TG metabolism in both males and females remains unknown. Since low-density lipoprotein receptor (LDLR) regulates both TG clearance and very low density lipoprotein (VLDL) production, LDLR may be involved in CETP-mediated alterations in TG metabolism in both males and females. We hypothesize that LDLR is required for CETP to alter TG metabolism in both males and females. We used LDLR null mice with and without CETP to demonstrate that LDLR is required for CETP to raise plasma TGs and to impair TG clearance in males. We also demonstrate that LDLR is required for CETP to increase TG production and to increase the expression and activity of VLDL synthesis targets in response to estrogen. Additionally, we show that LDLR is required for CETP to enhance β-oxidation. These studies support that LDLR is required for CETP to regulate TG metabolism in both males and females.

Hypertension preserves the magnitude of microvascular flow-mediated dilation following transient elevation in intraluminal pressure

OBJECTIVE

The objective of this study was to measure flow-mediated dilation (FMD) prior to and following transient increases in intraluminal pressure (IILP) in resistance arterioles isolated from subjects with and without coronary artery disease (CAD) (CAD and non-CAD) and non-CAD subjects with hypertension.

METHODS

Arterioles were isolated from discarded surgical tissues (adipose and atrial) from patients without coronary artery disease (non-CAD; ≤1 risk factor, excluding hypertension), with CAD, and non-CAD patients with hypertension (hypertension as the only risk factor). To simulate transient hypertension, increased IILP was generated (150 mmHg, 30 min) by gravity. Arterioles were constricted with endothelin-1, followed by FMD and endothelial-independent dilation prior to and following exposure to IILP.

RESULTS

IILP reduced FMD in non-CAD and CAD arterioles relative to pre-IILP (p <.05 at 100 cmH2 O). In contrast, arterioles from non-CAD hypertensive subjects exhibited no reduction in maximal FMD following IILP (p = .84 at 100 cmH2 O). FMD was reduced by L-NAME prior to IILP in non-CAD hypertensive patients (p < .05 at 100 cmH2 O); however, following IILP, FMD was inhibited by peg-cat (p < .05 at 100 cmH2 O), indicating a switch from NO to H2 O2 as the mechanism of dilation.

CONCLUSIONS

Acute exposure (30 min) to IILP (150 mmHg) attenuates the magnitude of FMD in non-CAD and CAD resistance arterioles. The presence of clinically diagnosed hypertension in non-CAD resistance arterioles preserves the magnitude of FMD following IILP as a result of a compensatory switch from NO to H2 O2 as the mechanism of dilation.

Hypertension and endothelial dysfunction in the pristane model of systemic lupus erythematosus

Autoimmune diseases such as psoriasis, rheumatoid arthritis, and systemic lupus erythematosus (SLE) have high rates of hypertension and cardiovascular disease. Systemic lupus erythematosus is a prototypic autoimmune disorder that primarily affects women of childbearing age and is associated with a loss of self-tolerance, autoreactive B and T lymphocytes, and the production of autoantibodies, especially to nuclear components. In this study, we hypothesized that the pristane-inducible model of SLE would develop hypertension and vascular dysfunction as the disease progressed. To test this hypothesis, female C57BL/6 mice were administered PBS or pristane. Seven months after pristane administration, mice developed various autoantibodies, including anti-dsDNA IgG, anti-ssDNA IgG, and anti-nRNP IgG, as well as hypergammaglobulinemia. Several other immunological changes, including increased circulating neutrophils and increased CD4- CD8- (double negative) thymocytes were also detected. Mean arterial pressure (MAP) was elevated in pristane-treated mice when compared to PBS-treated mice. In addition, second-order mesenteric arteries from pristine-treated mice had impaired relaxation to the endothelium-dependent vasodilator acetylcholine compared to PBS-treated mice. These data suggest that the immune system dysfunction present in the pristane model of lupus contributes to the development of hypertension and vascular dysfunction.

CD4+ T Cell-Specific Proteomic Pathways Identified in Progression of Hypertension Across Postmenopausal Transition

Background Menopause is associated with an increase in the prevalence and severity of hypertension in women. Although premenopausal females are protected against T cell-dependent immune activation and development of angiotensin II (Ang II) hypertension, this protection is lost in postmenopausal females. Therefore, the current study hypothesized that specific CD4+ T cell pathways are regulated by sex hormones and Ang II to mediate progression from premenopausal protection to postmenopausal hypertension. Methods and Results Menopause was induced in C57BL/6 mice via repeated 4-vinylcyclohexene diepoxide injections, while premenopausal females received sesame oil vehicle. A subset of premenopausal mice and all menopausal mice were infused with Ang II for 14 days (Control, Ang II, Meno/Ang II). Proteomic and phosphoproteomic profiles of CD4+ T cells isolated from spleens were examined. Ang II markedly increased CD4+ T cell protein abundance and phosphorylation associated with DNA and histone methylation in both premenopausal and postmenopausal females. Compared with premenopausal T cells, Ang II infusion in menopausal mice increased T cell phosphorylation of MP2K2, an upstream regulator of ERK, and was associated with upregulated phosphorylation at ERK targeted sites. Additionally, Ang II infusion in menopausal mice decreased T cell phosphorylation of TLN1, a key regulator of IL-2Rα and FOXP3 expression. Conclusions These findings identify novel, distinct T cell pathways that influence T cell-mediated inflammation during postmenopausal hypertension.

Trends, Management, and Outcomes of Acute Myocardial Infarction Hospitalizations With In-Hospital-Onset Versus Out-of-Hospital Onset: The ARIC Study

Background Acute myocardial infarction (AMI) with in-hospital onset (AMI-IHO) has poor prognosis but is clinically underappreciated. Whether its occurrence has changed over time is uncertain. Methods and Results Since 1987, the ARIC (Atherosclerosis Risk in Communities) study has conducted adjudicated surveillance of AMI hospitalizations in 4 US communities. Our analysis was limited to patients aged 35 to 74 years with symptomatic AMI. Patients with symptoms initiating after hospital arrival were considered AMI-IHO. A total of 26 678 weighted hospitalizations (14 276 unweighted hospitalizations) for symptomatic AMI were identified from 1995 to 2014, with 1137 (4%) classified as in-hospital onset. The population incidence rate of AMI-IHO increased in the 4 ARIC communities from 1995 through 2004 to 2005 through 2014 (12.7-16.9 events per 100 000 people; P for 20-year trend <0.0001), as did the proportion of AMI hospitalizations with in-hospital onset (3.7%-6.1%; P for 20-year trend =0.03). The 10-year proportions were stable for patients aged 35 to 64 years (3.0%-3.4%; P for 20-year trend =0.3) but increased for patients aged ≥65 years (4.6%-7.8%; P for 20-year trend =0.008; P for interaction by age group =0.04). AMI-IHO had a more severe clinical course with lower use of AMI therapies or invasive strategies and higher in-hospital (7% versus 3%), 28-day (19% versus 5%), and 1-year (29% versus 12%) mortality (P<0.0001 for all). Conclusions In this population-based community surveillance, AMI-IHO increased from 2005 to 2014, particularly among older patients. Quality initiatives to improve recognition and management of AMI-IHO should be especially focused on hospitalized patients aged >65.

Impact of diabetes on serum biomarkers in heart failure with preserved ejection fraction: insights from the TOPCAT trial

Aims

Diabetes mellitus (DM) is common in heart failure with preserved ejection fraction (HFpEF). Patients with DM and heart failure with reduced ejection fraction have higher levels of cardiac, profibrotic, and proinflammatory biomarkers relative to non‐diabetics. Limited data are available regarding the biomarker profiles of HFpEF patients with diabetes (DM) vs. no diabetes (non‐DM) and the impact of spironolactone on these biomarkers. This study aims to address such gaps in the literature.

Methods and results

Biomarkers were measured at randomization and at 12 months in 248 patients enrolled in Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist's North American cohort. At baseline, DM patients had significantly lower estimated glomerular filtration rate and higher high‐sensitivity C‐reactive protein, pro‐collagen type III amino‐terminal peptide, tissue inhibitor of metalloproteinase 1 (TIMP‐1), and galectin‐3 levels than those without diabetes. There was a significantly larger 12 month increase in levels of high‐sensitivity troponin T (hs‐TnT), a marker of myocyte death, in DM patients. Elevated pro‐collagen type III amino‐terminal peptide and galectin‐3 levels were associated with an increased risk of the primary outcome (cardiovascular mortality, aborted cardiac arrest, or heart failure hospitalization) in DM patients, but not in those without diabetes. A statistically significant interaction between spironolactone and diabetes status was observed for hs‐TnT and for TIMP‐1, with greater biomarker reductions among those with diabetes treated with spironolactone.

Conclusions

The presence of diabetes is associated with higher levels of cardiac, profibrotic, and proinflammatory biomarkers in HFpEF. Spironolactone appears to alter the determinants of extracellular matrix remodelling in an anti‐fibrotic fashion in patients with diabetes, reflected by changes in hs‐TnT and TIMP‐1 levels over time.

Proteomic Signatures of Lifestyle Risk Factors for Cardiovascular Disease: A Cross-Sectional Analysis of the Plasma Proteome in the Framingham Heart Study

Background Proteomic biomarkers related to cardiovascular disease risk factors may offer insights into the pathogenesis of cardiovascular disease. We investigated whether modifiable lifestyle risk factors for cardiovascular disease are associated with distinctive proteomic signatures. Methods and Results We analyzed 1305 circulating plasma proteomic biomarkers (assayed using the SomaLogic platform) in 897 FHS (Framingham Heart Study) Generation 3 participants (mean age 46±8 years; 56% women; discovery sample) and 1121 FOS (Framingham Offspring Study) participants (mean age 52 years; 54% women; validation sample). Participants were free of hypertension, diabetes mellitus, and clinical cardiovascular disease. We used linear mixed effects models (adjusting for age, sex, body mass index, and family structure) to relate levels of each inverse-log transformed protein to 3 lifestyle factors (ie, smoking, alcohol consumption, and physical activity). A Bonferroni-adjusted P value indicated statistical significance (based on number of proteins and traits tested, P<4.2×10-6 in the discovery sample; P<6.85×10-4 in the validation sample). We observed statistically significant associations of 60 proteins with smoking (37/40 top proteins validated in FOS), 30 proteins with alcohol consumption (23/30 proteins validated), and 5 proteins with physical activity (2/3 proteins associated with the physical activity index validated). We assessed the associations of protein concentrations with previously identified genetic variants (protein quantitative trait loci) linked to lifestyle-related disease traits in the genome-wide-association study catalogue. The protein quantitative trait loci were associated with coronary artery disease, inflammation, and age-related mortality. Conclusions Our cross-sectional study from a community-based sample elucidated distinctive sets of proteins associated with 3 key lifestyle factors.

Murine cadherin-6 mediates thrombosis in vivo in a platelet-independent manner

BACKGROUND

Platelet adhesion is the critical process mediating stable thrombus formation. Previous reports of cadherin-6 on human platelets have demonstrated its role in platelet aggregation and thrombus formation.

OBJECTIVES

We aimed to further characterize the importance of cadherin-6 in thrombosis in vivo.

METHODS

Cadherin-6 platelet expression was evaluated by western blotting, flow cytometry, and immunoprecipitation. Thrombosis was evaluated using the FeCl3 and Rose Bengal carotid artery models in C57Bl6 mice treated with anti-cadherin-6 or IgG and wild-type or Cdh6-/- mice. Platelet function was compared in wild-type and Cdh6-/- mice using tail-clip assays, aggregometry, and flow cytometry.

RESULTS

Human platelet expression of cadherin-6 was confirmed at ~3000 copies per platelet. Cdh6-/- mice or those treated with anti-cadherin-6 antibody showed an increased time to occlusion in both thrombosis models. Cadherin-6 was not expressed on mouse platelets, and there were no differences in tail bleeding times, platelet aggregation, or platelet activation in wild-type versus Cdh6-/- mice.

CONCLUSIONS

Cadherin-6 plays an essential role in thrombosis in vivo. However, cadherin-6 is not expressed on murine platelets. These data are in contrast to human platelets, which express a functional cadherin-6/catenin complex. The essential, platelet-independent role for cadherin-6 in hemostasis may allow it to be an effective and safe therapeutic target.

High-salt intake reduces renal tissue levels of inflammatory cytokines in mice

High salt (HS) intake is usually considered as an aggravating factor to induce inflammatory renal injury. However, the changes in the renal levels of inflammatory cytokines during HS intake is not yet clearly defined. We hypothesize that HS increases renal levels of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) but decreases interleukin-10 (IL-10; anti-inflammatory cytokine) and these responses exacerbate in NO deficient conditions. Both wild-type (WT) and endothelial NO synthase knockout (eNOSKO) mice (~8 weeks old, n = 6 in each group) were given normal-salt (NS; 0.3% NaCl) and HS (4% NaCl) containing diets for 2 weeks. Systolic blood pressure (SBP) was determined by tail-cuff plethysmography and urine collections were made using metabolic cages. Basal SBP was higher in eNOSKO than WT mice (131 ± 7 vs 117 ± 3 mmHg; p < .05). HS intake for 2 weeks increased SBP in eNOSKO (161 ± 5 mmHg) but not in WT mice. In NS groups, the cytokine levels in renal tissues (measured using ELISA kits and expressed in pg/mg protein) were significantly higher in eNOSKO than WT mice (TNF-α, 624 ± 67 vs. 325 ± 73; IL-6, 619 ± 106 vs. 166 ± 61; IL-10, 6,087 ± 567 vs. 3,929 ± 378). Interestingly, these cytokine levels in HS groups were significantly less both in WT (TNF-α, 114 ± 17; IL-6, 81 ± 14; IL-10, 865 ± 130) and eNOSKO (TNF-α, 115 ± 18; IL-6, 56 ± 7; IL-10, 882 ± 141) mice. These findings indicate that HS induces downregulation of cytokines in the kidney. Such HS-induced reduction in cytokines, particularly TNF-α (a natriuretic agent), would facilitate more salt-retention, and thus, leading to salt-sensitive hypertension in NO deficient conditions.

α-Adrenergic receptor blockade attenuates pressor response during mental stress in young black adults

Black individuals exhibit increased blood pressure (BP) responses to sympathetic stimulation that are associated with an increased risk of hypertension (HTN). We tested the hypothesis that α1 -adrenergic blockade inhibits the increased BP response during and after 45-min stress in young normotensive Black adults, which may be mediated, in part, by dampened vasoconstriction and decreased renal sodium retention. Utilizing a double-masked randomized, crossover study design, 51 normotensive Black adults (31 ± 8 yr) were treated with either a placebo or 1 mg/day of prazosin for 1 week. On the final day of each treatment, hemodynamic measures and urinary sodium excretion (UNaV) were collected before (Rest), during (Stress) and after (Recovery) 45 min of mental stress induced via a competitive video game task. During the Stress period, diastolic BP and total peripheral resistance (TPR) were significantly lower with prazosin compared to placebo (p < .05 for both). Similarly, we observed lower systolic BP, diastolic BP, and TPR during the Recovery period with prazosin versus placebo (p < .05 for both). There was no effect of prazosin on stress-associated UNaV. The change in systolic BP from Rest to Recovery was positively associated with the change in TPR with both treatments (p < .05 for both). In summary, prazosin treatment dampened BP reactivity to 45-min mental stress and lowered post-stress BP over the recovery period, which was linked to reduce TPR in young normotensive Black adults. These results suggest that α1 -adrenergic receptor activity may contribute to BP responses and delayed BP recovery to prolonged mental stress through increased vasoconstriction in Black adults.

ECHS1 disease in two unrelated families of Samoan descent: Common variant - rare disorder

Mutations in the short-chain enoyl-CoA hydratase (SCEH) gene, ECHS1, cause a rare autosomal recessive disorder of valine catabolism. Patients usually present with developmental delay, regression, dystonia, feeding difficulties, and abnormal MRI with bilateral basal ganglia involvement. We present clinical, biochemical, molecular, and functional data for four affected patients from two unrelated families of Samoan descent with identical novel compound heterozygous mutations. Family 1 has three affected boys while Family 2 has an affected daughter, all with clinical and MRI findings of Leigh syndrome and intermittent episodes of acidosis and ketosis. WES identified a single heterozygous variant in ECHS1 at position c.832G > A (p.Ala278Thr). However, western blot revealed significantly reduced ECHS1 protein for all affected family members. Decreased SCEH activity in fibroblasts and a mild increase in marker metabolites in urine further supported ECHS1 as the underlying gene defect. Additional investigations at the DNA (aCGH, WGS) and RNA (qPCR, RT-PCR, RNA-Seq, RNA-Array) level identified a silent, common variant at position c.489G > A (p.Pro163=) as the second mutation. This substitution, present at high frequency in the Samoan population, is associated with decreased levels of normally spliced mRNA. To our understanding, this is the first report of a novel, hypomorphic allele c.489G > A (p.Pro163=), associated with SCEH deficiency.

Complement factor C4a does not activate protease-activated receptor 1 (PAR1) or PAR4 on human platelets

BACKGROUND

Protease-activated receptor (PAR) 1 and PAR4 are key thrombin signal mediators for human platelet activation and aggregation in response to vascular injury. They are primarily activated by thrombin cleavage of the N-terminus to expose a tethered ligand. In addition to the canonical activation by thrombin, a growing panel of proteases can also elicit PAR1- or PAR4-mediated signal transduction. Recently, complement factor C4a was reported as the first endogenous agonist for both PAR1 and PAR4. Further, it is the first endogenous nontethered ligand that activates PAR1 and PAR4. These studies were conducted with human microvascular cells; the impact of C4a on platelet PARs is unknown.

OBJECTIVES

The goal of this study was to interrogate PAR1 and PAR4 activation by C4a on human platelets.

METHODS

Platelet-rich plasma (PRP) was isolated from healthy donors. PRP was stimulated with C4a, and the platelet aggregation was measured. Human embryonic kidney (HEK) 293 Flp-In T-rex cells were used to further test if C4a stimulation can initiate PAR1- or PAR4-mediated Gαq signaling, which was measured by intracellular calcium mobilization.

RESULTS

C4a failed to elicit platelet aggregation via PAR1- or PAR4-mediated manner. In addition, no PAR1- or PAR4-mediated calcium mobilization was observed upon C4a stimulation on HEK293 cells.

CONCLUSIONS

Complement factor C4a does not activate PAR1 or PAR4 on human platelets. These data show that PAR1 and PAR4 activation by C4a on microvascular cells likely requires a cofactor, which reinforces the concept of cell type-specific regulation of protease signaling.

Thrombocytosis with acquired von Willebrand disease in an adolescent with sickle cell disease

Thrombocytosis is common in sickle cell disease and may contribute to vaso-occlusion. Hydroxyurea treats extreme thrombocytosis. Acquired von Willebrand disease should be considered prior to aspirin therapy.