Circulating microRNAs (miRs) may reflect pathophysiologically relevant processes in the atherosclerotically diseased coronary arterial wall. Given the unmet medical need to identify patients with an unstable plaque phenotype, we determined the relation of circulating atherosclerosis-regulatory miRs with plaque phenotypes. We assessed coronary atherosclerotic plaque burden and phenotype by optical coherence tomography in 52 patients and measured the levels of circulating miRs across the transcoronary gradient. The overall plaque load was significantly correlated with transcoronary concentration gradients of miR-126-3p (P = 0.04), miR-145-5p (P = 0.01), miR-155-5p (P < 0.01), and miR-29b-3p (P = 0.02), but not with other miRs such as miR-92a-3p. In patients with a high extent of vulnerable plaques as assessed by the presence of thin-cap fibroatheromas (TCFAs), significantly higher transcoronary gradients were observed, particularly for miR-126-3p, miR-126-5p, and miR-145-5p (all P < 0.02). Transcoronary gradients of miR-126-3p (P < 0.01), miR-126-5p (P < 0.01), miR-145-5p (P = 0.01), miR-29b-3p (P = 0.03), and miR-155-5p (P = 0.02) demonstrated a significant discriminatory power to predict the presence of TCFAs (AUC > 0.7 for all). Moreover, aortic and venous coronary sinus levels of miR-29b-3p were inversely correlated with plaque fibrosis, a finding that is consistent with the anti-fibrotic activity of miR-29b-3p. The overall plaque burden and plaque phenotypes are associated with changes in the kinetics of miR-concentrations across the transcoronary passage. Transcoronary gradients of the anti-atherosclerotic miR-126-3p and miR-145-5p correlated with the extent of TCFAs, suggesting that instable plaques may affect the local uptake or degradation of these miRs.

Rationale:: Endothelial progenitor cells (EPCs) are present in the systemic circulation and home to sites of ischemic injury where they promote neoangiogenesis. β ₂ -Adrenergic receptor (β ₂ AR) plays a critical role in vascular tone regulation and neoangiogenesis. Objective:: We aimed to evaluate the role of β ₂ AR on EPCs’ function. Methods and Results:: We firstly performed in vitro analysis showing the expression of β ₂ AR on EPCs. Stimulation of wild-type EPCs with β-agonist isoproterenol induced a significant increase of Flk-1 expression on EPCs as assessed by fluorescence-activated cell sorter. Moreover, β ₂ AR stimulation induced a significant increase of cell proliferation, improved the EPCs migratory activity, and enhanced the EPCs’ ability to promote endothelial cell network formation in vitro. Then, we performed in vivo studies in animals model of hindlimb ischemia. Consistent with our in vitro results, in vivo EPCs’ treatment resulted in an improvement of impaired angiogenic phenotype in β ₂ AR KO mice after induction of ischemia, whereas no significant amelioration was observed when β ₂ AR knock out (KO) EPCs were injected. Indeed, wild-type–derived EPCs’ injection resulted in a significantly higher blood flow restoration in ischemic hindlimb and higher capillaries density at histological analysis as compared with not treated or β ₂ AR KO EPC-treated mice. Conclusions:: The present study provides the first evidence that EPCs express a functional β ₂ AR. Moreover, β ₂ AR stimulation results in EPCs proliferation, migration, and differentiation, enhancing their angiogenic ability, both in vitro and in vivo, leading to an improved response to ischemic injury in animal models of hindlimb ischemia.

Background: The clinical impact of PlA2 polymorphism has been investigated in several diseases, but the definition of its specific role on thrombotic cardiovascular complications has been challenging. We aimed to explore the effect of PlA2 polymorphism on outcome in patients with atherosclerosis. Methods: We studied 400 consecutive patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention. A replication study was conducted in 74 hypertensive patients with cerebrovascular events while a group of 100 healthy subjects was included as control population. PlA genotype was determined by PCR-RFLP on genomic DNA from peripheral blood cells. Major adverse cardiac events (MACE), were considered as end points, and recorded at a mean follow up of 24 ± 4.3 months. Results: The frequencies of PlA2 polymorphism was similar between groups and genotype distribution was in Hardy-Weinberg equilibrium. In patients with CAD, the presence of PlA2 allele was associated with higher incidence of cardiac death (13.1% vs. 1.5%, p = 0.0001), myocardial infarction (10.7% vs. 2.6%, p = 0.004) and needs of new revascularization (34.8% vs. 17.7%, p = 0.010). Accordingly, the Kaplan-Meier analysis for event free survival in patients harboring the PlA2 allele showed worse long-term outcome for these patients (p = 0.015). Cox regression analysis identified the presence of PlA2 as an independent predictor of cardiac death (OR: 9.594, 95% CI: 2.6 to 35.3, p = 0.002) and overall MACE (OR: 1.829, 95% CI: 1.054 to 3.176, p = 0.032). In the replication study, the PlA2 polymorphism increased the risk of stroke (OR: 4.1, 95% CI: 1.63-12.4, p = 0.02) over TIA and was identified as an independent risk factor for stroke (B:-1.39; Wald: 7.15; p = 0.001). Conclusions: Our study demonstrates that in patients with severe atherosclerosis the presence of PlA2 allele is associated with thrombotic cardiovascular complications.

Aims: Several studies have shown that muscle mass loss is an important pathogenic issue in heart failure (HF). Atrogin-1 is a F-box protein selectively expressed in cardiac and skeletal muscle tissue, which plays a pivotal role in muscle wasting regulation. The aim of this study was to investigate the expression of Atrogin-1 and the molecular pathway involved in Atrogin-1 regulation in human HF. Methods and results: Cardiac tissue from patients with HF (HF group: n = 10) or with normal left ventricular function (control group: n = 9) was studied by western blot and real time-PCR analysis. Linear regression analysis between patients left ventricular ejection fraction (LVEF) and Atrogin1 or its regulator Forkhead box O 3a (Foxo3a) myocardial expression was performed to test correlations between protein expression and LVEF. Western blot analysis revealed that the myocardial expression of Atrogin-1 in the HF group was 2.5-fold increased compared with controls (P = 0.007). Accordingly, Atrogin-1 mRNA was 1.5 higher than in controls (P = 0.003). The expression of Foxo3a and its up-stream regulator AKT were also measured. Western blot analysis demonstrated in the HF group a 2.56-fold reduction of AKT phosphorylation and a 3.32-fold increase of Foxo3a as compared with controls (P = 0.002 and P = 0.001, respectively). Finally, linear regression showed a significant relationship between Foxo3a or Atrogin-1 expression and LVEF (R = 0.976, P < 0.0001 and R = 0.895, P = 0.003, respectively). Conclusion: Our results suggest that in human HF, the activity of AKT decreases, with activation of Foxo3a and induction of Atrogin-1, thereby leading to a molecular state that favours heart muscle loss and left ventricular dysfunction.

The association between cardiovascular risk factors (CVRF) and the risk of coronary events is widely acknowledged. Whether individual risk factors may be associated with distinct plaque characteristics is currently unclear. We investigated the relationship between CVRF and coronary plaque burden and phenotype.Methods and Results:We assessed coronary atherosclerotic plaque characteristics by optical coherence tomography in 67 patients with stable coronary artery disease undergoing coronary angiography. The plaque burden and the distinct plaque phenotypes were compared with regard to different CVRF. Overall plaque burden was significantly greater in patients with diabetes mellitus (P=0.010), prediabetes (P=0.035) and obesity (P=0.024), and correlated with the number of CVRF (R=0.358, P=0.003). Patients with diabetes had a greater extent of fibroatheroma (P=0.015), calcific fibroatheroma (P=0.031), thin-cap fibroatheroma (TCFA-P=0.011) and plaque erosion (P=0.002). Obese patients showed a greater extent of fibroatheroma (P=0.007), TCFA (P=0.015) and macrophage load (P=0.043). The number of CVRF correlated with fibroatheroma (R=0.425, P<0.001), calcific fibroatheroma (R=0.321, P=0.008), TCFA (R=0.347, P=0.004), macrophage load (R=0.314, P=0.010) and erosion (R=0.271, P=0.029). In the multivariate analysis, altered glycemic status and obesity were the only independent predictors of TCFA (P=0.026 and P=0.046, respectively), whereas altered glycemic status was the only independent predictor of plaque erosion (P=0.001). Patients with diabetes, prediabetes and obesity show more extensive coronary atherosclerosis and more vulnerable plaque phenotypes.