Mosaab Awad

Soluble Urokinase Receptor and Chronic Kidney Disease

BACKGROUND Relatively high plasma levels of soluble urokinase-type plasminogen activator receptor (suPAR) have been associated with focal segmental glomerulosclerosis and poor clinical outcomes in patients with various conditions. It is unknown whether elevated suPAR levels in patients with normal kidney function are associated with future decline in the estimated glomerular filtration rate (eGFR) and with incident chronic kidney disease. METHODS We measured plasma suPAR levels in 3683 persons enrolled in the Emory Cardiovascular Biobank (mean age, 63 years; 65% men; median suPAR level, 3040 pg per milliliter) and determined renal function at enrollment and at subsequent visits in 2292 persons. The relationship between suPAR levels and the eGFR at baseline, the change in the eGFR over time, and the development of chronic kidney disease (eGFR <60 ml per minute per 1.73 m(2) of body-surface area) were analyzed with the use of linear mixed models and Cox regression after adjustment for demographic and clinical variables. RESULTS A higher suPAR level at baseline was associated with a greater decline in the eGFR during follow-up; the annual change in the eGFR was -0.9 ml per minute per 1.73 m(2) among participants in the lowest quartile of suPAR levels as compared with -4.2 ml per minute per 1.73 m(2) among participants in the highest quartile (P<0.001). The 921 participants with a normal eGFR (≥ 90 ml per minute per 1.73 m(2)) at baseline had the largest suPAR-related decline in the eGFR. In 1335 participants with a baseline eGFR of at least 60 ml per minute per 1.73 m(2), the risk of progression to chronic kidney disease in the highest quartile of suPAR levels was 3.13 times as high (95% confidence interval, 2.11 to 4.65) as that in the lowest quartile. CONCLUSIONS An elevated level of suPAR was independently associated with incident chronic kidney disease and an accelerated decline in the eGFR in the groups studied. (Funded by the Abraham J. and Phyllis Katz Foundation and others.).

Platelets confound the measurement of extracellular miRNA in archived plasma

Extracellular miRNAs are detectable in biofluids and represent a novel class of disease biomarker. Although many studies have utilized archived plasma for miRNA biomarker discovery, the effects of processing and storage have not been rigorously studied. Previous reports have suggested plasma samples are commonly contaminated by platelets, significantly confounding the measurement of extracellular miRNA, which was thought to be easily addressed by additional post-thaw plasma processing. In a case-control study of archived plasma, we noted a significant correlation between miRNA levels and platelet counts despite post-thaw processing. We thus examined the effects of a single freeze/thaw cycle on microparticles (MPs) and miRNA levels, and show that a single freeze/thaw cycle of plasma dramatically increases the number of platelet-derived MPs, contaminates the extracellular miRNA pool, and profoundly affects the levels of miRNAs detected. The measurement of extracellular miRNAs in archived samples is critically dependent on the removal of residual platelets prior to freezing plasma samples. Many previous clinical studies of extracellular miRNA in archived plasma should be interpreted with caution and future studies should avoid the effects of platelet contamination.

Circulating Progenitor Cells Identify Peripheral Arterial Disease in Patients With Coronary Artery Disease

RATIONALE Peripheral arterial disease (PAD) is a clinical manifestation of extracoronary atherosclerosis. Despite sharing the same risk factors, only 20% to 30% of patients with coronary artery disease (CAD) develop PAD. Decline in the number of bone marrow-derived circulating progenitor cells (PCs) is thought to contribute to the pathogenesis of atherosclerosis. Whether specific changes in PCs differentiate patients with both PAD and CAD from those with CAD alone is unknown. OBJECTIVE Determine whether differences exist in PCs counts of CAD patients with and without known PAD. METHODS AND RESULTS 1497 patients (mean age: 65 years; 62% men) with known CAD were identified in the Emory Cardiovascular Biobank. Presence of PAD (n=308) was determined by history, review of medical records, or imaging and was classified as carotid (53%), lower extremity (41%), upper extremity (3%), and aortic disease (33%). Circulating PCs were enumerated by flow cytometry. Patients with CAD and PAD had significantly lower PC counts compared with those with only CAD. In multivariable analysis, a 50% decrease in cluster of differentiation 34 (CD34+) or CD34+/vascular endothelial growth factor receptor-2 (VEGFR2+) counts was associated with a 31% (P=0.032) and 183% (P=0.002) increase in the odds of having PAD, respectively. CD34+ and CD34+/VEGFR2+ counts significantly improved risk prediction metrics for prevalent PAD. Low CD34+/VEGFR2+ counts were associated with a 1.40-fold (95% confidence interval, 1.03-1.91) and a 1.64-fold (95% confidence interval, 1.07-2.50) increases in the risk of mortality and PAD-related events, respectively. CONCLUSIONS PAD is associated with low CD34+ and CD34+/VEGFR2+ PC counts. Whether low PC counts are useful in screening for PAD needs to be investigated.

Depression and chest pain in patients with coronary artery disease

BACKGROUND Depression is common in patients with coronary artery disease (CAD) and is associated with more frequent chest pain. It is however unclear whether this is due to differences in underlying CAD severity. We sought to determine [1] whether depressive symptoms are associated with chest pain independently of CAD severity, [2] whether improvement in depressive symptoms over time is associated with improvement in chest pain and [3] whether the impact of revascularization on chest pain differs between patients with and without depression. METHODS AND RESULTS 5158 patients (mean age 63±12years, 65% male, 20% African American) undergoing cardiac catheterization completed the Seattle Angina Questionnaire (SAQ) and Patient Health Questionnaire-8 (PHQ-8) to assess angina severity and screen for depression, respectively, both at baseline and between 6 and 24months of follow-up. We found significant correlations between PHQ-8 scores and angina frequency (SAQ-AF, r=-0.28), physical limitation (SAQ-PL, r=-0.32) and disease perception (SAQ-DS r=-0.37, all P<0.001), which remained significant after adjustment for clinical characteristics, CAD severity, and anti-depressant use. Improvement in depressive symptoms at follow-up was associated with improvement in angina subscales (SAQ-AF β 1.34, P<0.001), SAQ-PL β 1.85, P<0.001), and SAQ-DS (β 2.12, P<0.001), independently of CAD severity or revascularization. Patients with depression who underwent revascularization had less improvement in chest pain frequency than those without depressive symptoms. CONCLUSIONS Depression is associated with angina, independently of CAD severity. Patients with depression may not derive as adequate symptomatic benefit from revascularization as those without. Whether treatment of underlying depression improves chest pain needs to be further studied.

Computational fluid dynamics applied to virtually deployed drug-eluting coronary bioresorbable scaffolds: Clinical translations derived from a proof-of-concept

Background: Three-dimensional design simulations of coronary metallic stents utilizing mathematical and computational algorithms have emerged as important tools for understanding biomechanical stent properties, predicting the interaction of the implanted platform with the adjacent tissue, and informing stent design enhancements. Herein, we demonstrate the hemodynamic implications following virtual implantation of bioresorbable scaffolds using finite element methods and advanced computational fluid dynamics (CFD) simulations to visualize the device-flow interaction immediately after implantation and following scaffold resorption over time. Methods and Results: CFD simulations with time averaged wall shear stress (WSS) quantification following virtual bioresorbable scaffold deployment in idealized straight and curved geometries were performed. WSS was calculated at the inflow, endoluminal surface (top surface of the strut), and outflow of each strut surface post-procedure (stage I) and at a time point when 33% of scaffold resorption has occurred (stage II). The average WSS at stage I over the inflow and outflow surfaces was 3.2 and 3.1 dynes/cm2 respectively and 87.5 dynes/cm2 over endoluminal strut surface in the straight vessel. From stage I to stage II, WSS increased by 100% and 142% over the inflow and outflow surfaces, respectively, and decreased by 27% over the endoluminal strut surface. In a curved vessel, WSS change became more evident in the inner curvature with an increase of 63% over the inflow and 66% over the outflow strut surfaces. Similar analysis at the proximal and distal edges demonstrated a large increase of 486% at the lateral outflow surface of the proximal scaffold edge. Conclusions: The implementation of CFD simulations over virtually deployed bioresorbable scaffolds demonstrates the transient nature of device/flow interactions as the bioresorption process progresses over time. Such hemodynamic device modeling is expected to guide future bioresorbable scaffold design.

Bioactive Lipids and Circulating Progenitor Cells in Patients with Cardiovascular Disease

Bone marrow‐derived progenitor cells are mobilized into the peripheral blood after acute myocardial injury and in chronic ischemic heart disease. However, the mechanisms responsible for this mobilization are poorly understood. We examined the relationship between plasma levels of bioactive lipids and number of circulating progenitor cells (CPCs) in patients (N = 437) undergoing elective or emergent cardiac catheterization. Plasma levels of sphingosine‐1 phosphate (S1P) and ceramide‐1 phosphate (C1P) were quantified using mass spectrometry. CPCs were assessed using flow cytometry. S1P levels correlated with the numbers of CD34+, CD34+/CD133+, and CD34+/CXCR4+ CPCs even after adjustment for potential confounding factors. However, no significant correlation was observed between C1P levels and CPC count. Plasma levels of S1P correlated with the number of CPCs in patients with coronary artery disease, suggesting an important mechanistic role for S1P in stem cell mobilization. The therapeutic effects of adjunctive S1P therapy to mobilize endogenous stem cells need to be investigated. Stem Cells Translational Medicine 2017;6:731–735

Cardiovascular Disease Biomarkers and suPAR in Predicting Decline in Renal Function: A Prospective Cohort Study

Introduction Soluble urokinase-type plasminogen activator receptor (suPAR) strongly predicts outcomes and incident chronic kidney disease (CKD) in patients with cardiovascular disease (CVD). Whether the association between suPAR and CKD is a reflection of its overall association with chronic inflammation and poor CVD outcomes is unclear. We examined whether CVD biomarkers, including high-sensitivity C-reactive protein (hs-CRP), fibrin-degradation products (FDPs), heat-shock protein 70 (HSP-70), and high-sensitivity troponin I (hs-TnI) were associated with a decline in kidney function in the Emory Cardiovascular Biobank cohort, in which suPAR levels were shown to be predictive of both incident CKD and CVD outcomes. Methods We measured suPAR, hs-CRP, HSP-70, FDP, and hs-TnI plasma levels in 3282 adults (mean age 63 years, 64% male, 75% estimated glomerular filtration rate [eGFR] >60 ml/min per 1.73 m2). Glomerular filtration rate was estimated using Chronic Kidney Disease–Epidemiology Collaboration (eGFR) at enrollment (n = 3282) and follow-up (n = 2672; median 3.5 years). Urine protein by dipstick at baseline was available for 1335 subjects. Results There was a weak correlation among biomarkers (r range: 0.17−0.28). hs-CRP, FDPs, hs-TnI, and suPAR were independently associated with baseline eGFR and proteinuria. The median yearly decline in eGFR was −0.6 ml/min per 1.73 m2. hs-CRP (β: −0.04; P = 0.46), FDPs (β: −0.13; P = 0.08), HSP-70 (β: 0.05; P = 0.84), or hs-TnI (β: −0.01; P = 0.76) were associated with eGFR decline. suPAR remained predictive of eGFR decline even after adjusting for all biomarkers. Discussion hs-CRP, FDP, HSP-70, and hs-TnI were not associated with eGFR decline. The specific association of suPAR with eGFR decline supported its involvement in pathways specific to the pathogenesis of kidney disease.

Marital Status and Outcomes in Patients With Cardiovascular Disease

Background Being unmarried is associated with decreased survival in the general population. Whether married, divorced, separated, widowed, or never‐married status affects outcomes in patients with cardiovascular disease has not been well characterized. Methods and Results A prospective cohort (inception period 2003–2015) of 6051 patients (mean age 63 years, 64% male, 23% black) undergoing cardiac catheterization for suspected or confirmed coronary artery disease was followed for a median of 3.7 years (interquartile range: 1.7–6.7 years). Marital status was stratified as married (n=4088) versus unmarried (n=1963), which included those who were never married (n=451), divorced or separated (n=842), or widowed (n=670). The relationship between marital status and primary outcome of cardiovascular death and myocardial infarction was examined using Cox regression models adjusted for clinical characteristics. There were 1085 (18%) deaths from all causes, 688 (11%) cardiovascular‐related deaths, and 272 (4.5%) incident myocardial infarction events. Compared with married participants, being unmarried was associated with higher risk of all‐cause mortality (hazard ratio [HR]: 1.24; 95% confidence interval [CI], 1.06–1.47), cardiovascular death (HR: 1.45; 95% CI, 1.18–1.78), and cardiovascular death or myocardial infarction (HR: 1.52; 95% CI, 1.27–1.83). Compared with married participants, the increase in cardiovascular death or myocardial infarction was similar for the participants who were divorced or separated (HR: 1.41; 95% CI, 1.10–1.81), widowed (HR: 1.71; 95% CI, 1.32–2.20), or never married (HR: 1.40; 95% CI, 0.97–2.03). The findings persisted after adjustment for medications and other socioeconomic factors. Conclusions Marital status is independently associated with cardiovascular outcomes in patients with or at high risk of cardiovascular disease, with higher mortality in the unmarried population. The mechanisms responsible for this increased risk require further study.

The impact of moderate distance recreational running and ageing on cardiac physiology

Objective Exercise-induced cardiac dysfunction and corollary biomarker release have been documented following long-distance running events. To what degree these processes occur during shorter distance running events is unknown. Methods 72 healthy recreational runners (54% male/46% female) recruited by age (group 1 (18–20 years old, N=19); group 2 (45–50 years old, N=27); group 3 (70–75 years old, N=26)) were studied with echocardiography and biochemical profiling during participation in a 10 km running race. Results Despite age-dependent baseline differences in ventricular size and diastolic tissue velocities, there were no significant within group or across group decrements in ventricular systolic or diastolic function following race completion. Postrace increases in cardiac troponin-I (cTnI), B-type natriuretic peptide (BNP) and high-sensitivity C-reactive protein (hs-CRP) were common and demonstrated distinct age dependent profiles. Specifically, BNP increases were most pronounced among older runners (group 3Δ: 16±22 pg/mL, p=0.001), hs-CRP increased only among younger runners (group 1Δ: 1.5±2.7 mg/L, p=0.03) and cTnI increased in both younger (group 1Δ: 0.01±0.02 ng/mL, p=0.028) and older (group 3Δ: 0.01±0.01 ng/mL, p=0.007) runners, but not middle aged runners (group 2Δ: 0.00±0.00 ng/mL, p=0.57). Conclusions Moderate distance recreational running leads to distinct age-dependent biomarker release but is not associated with cardiac fatigue, a proposed stimulus for pathologic cardiac remodelling that has been observed following longer distance running events.

THE IMPACT OF AGE AND COMPLETION OF A MODERATE DISTANCE RUNNING RACE ON CARDIAC FUNCTION: RESULTS FROM P.E.A.C.H. (PROFILING THE EFFECTS OF AGING ON EXERCISE-INDUCED CHANGES IN CARDIAC MECHANICS)

Participation in ultra-endurance exercise is associated with transient cardiac dysfunction, or cardiac fatigue. The effects of aging and participation in a moderate distance running race on changes in cardiac function have not been studied. 73 healthy runners spanning a wide age spectrum [(Group 1