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In the last years, a substantial contribution of red blood cells (RBCs) in cardiovascular homeostasis has been evidenced, as these cells are able to regulate cardiovascular function by the export of adenosine triphosphate and nitric oxide as well as to maintain redox balance through a well-developed antioxidant system. Recently a link between high-risk plaque (HRP) features and myocardial ischemia, in the absence of severe lumen stenosis, has been evidenced. Nonobstructive coronary artery disease (nonob CAD) has been associated in fact with a greater 1-year risk of myocardial infarction and all-cause mortality compared with no apparent CAD. This new evidence increases interest in searching new triggers to identify these high-risk patients, in the absence/or on top of traditional hazard markers. In this study, we investigated the existence of any association between RBC morphodynamics and HRP features in individuals with different grades of coronary stenosis detected by coronary computed tomography angiography (CCTA). Ninety-one consecutive individuals who underwent CCTA [33 no CAD; 26 nonobstructive (nonob), and 32 obstructive (ob) CAD] were enrolled. RBC morphodynamic features, i.e., RBC aggregability and deformability, were analyzed by means of Laser Assisted Optical Rotation Cell Analyzer (LoRRca MaxSis). The putative global RBC morphodynamic (RMD) score and the related risk chart, associating the extent of HRP (e.g., the non-calcified plaque volume) with both the RMD score and the max % stenosis were computed. In nonob CAD group only positive correlations between RBC rigidity, osmotic fragility or aggregability and HRP features (plaque necrotic core, fibro-fatty and fibro-fatty plus necrotic core plaque volumes) were highlighted. Interestingly, in this patient cohort three of these RBC morphodynamic features result to be independent predictors of the presence of non-calcified plaque volume in this patients group. The risk chart created shows that only in nonob CAD plaque vulnerability increases according to the score quartile. Findings of this work, by evidencing the association between erythrocyte morphodynamic characteristics assessed by LoRRca and plaque instability in a high-risk cohort of nonob CAD, suggest the use of these blood cell features in the identification of high-risk patients, in the absence of severe coronary stenosis.

Introduction: Familial hypercholesterolemia (FH) is characterized by extremely high levels of circulating low-density lipoprotein cholesterol (LDL-C) and is caused by mutations of genes involved in LDL-C metabolism, including LDL receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin/Kexin type 9 (PCSK9). Accordingly, PCSK9 inhibitors (PCSK9i) are effective in LDL-C reduction. However, no data are available on the pleiotropic effect of PCSK9i. To this end, we performed an untargeted metabolomics approach to gather a global view on changes in metabolic pathways in patients receiving treatment with PCSK9i. Methods: Twenty-five FH patients starting treatment with PCSK-9i were evaluated by an untargeted metabolomics approach at baseline (before PCSK9i treatment) and after 12 weeks of treatment. Results: All the 25 FH subjects enrolled were on maximal tolerated lipid-lowering therapy prior to study entry. After a 12 week treatment with PCSK9i, we observed an expected significant reduction in LDL-cholesterol levels (from 201.0 ± 69.5 mg/dL to 103.0 ± 58.0 mg/dL, p < 0.001). The LDL-C target was achieved in 36% of patients. After peak validation and correction, after 12 weeks of PCSK9i treatment as compared to baseline, we observed increments in creatine (p-value = 0.041), indole (p-value = 0.045), and indoleacrylic acid (p-value= 0.045) concentrations. Conversely, significant decreases in choline (p-value = 0.045) and phosphatidylcholine (p-value < 0.01) together with a reduction in platelet activating factor (p-value = 0.041) were observed. Conclusions: Taking advantage of untargeted metabolomics, we first provided evidence of concomitant reductions in inflammation and platelet activation metabolites in FH patients receiving a 12 week treatment with PCSK9i.

Netrin-1 is a laminin-like protein that plays a pivotal role in cell migration and, according to the site of its release, exerts both pro and anti-atherosclerotic functions. Macrophages, key cells in atherosclerosis, are heterogeneous in morphology and function and different subpopulations may support plaque progression, stabilization, and/or regression. Netrin-1 was evaluated in plasma and, together with its receptor UNC5b, in both spindle and round monocyte-derived macrophages (MDMs) morphotypes from coronary artery disease (CAD) patients and control subjects. In CAD patients, plaque features were detected in vivo by optical coherence tomography. CAD patients had lower plasma Netrin-1 levels and a higher MDMs expression of both protein and its receptor compared to controls. Specifically, a progressive increase in Netrin-1 and UNC5b was evidenced going from controls to stable angina (SA) and acute myocardial infarction (AMI) patients. Of note, spindle MDMs of AMI showed a marked increase of both Netrin-1 and its receptor compared to spindle MDMs of controls. UNC5b expression is always higher in spindle compared to round MDMs, regardless of the subgroup. Finally, CAD patients with higher intracellular Netrin-1 levels showed greater intraplaque macrophage accumulation in vivo. Our findings support the role of Netrin-1 and UNC5b in the atherosclerotic process.

Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin growth factor family, well known for its role in the homeostasis of the cardiovascular system. Recently, the human BDNF Val66Met single nucleotide polymorphism has been associated with the increased propensity for arterial thrombosis related to acute myocardial infarction (AMI). Using cardiac magnetic resonance imaging and immunohistochemistry analyses, we showed that homozygous mice carrying the human BDNF Val66Met polymorphism (BDNFMet/Met) undergoing left anterior descending (LAD) coronary artery ligation display an adverse cardiac remodeling compared to wild-type (BDNFVal/Val). Interestingly, we observed a persistent presence of pro-inflammatory M1-like macrophages and a reduced accumulation of reparative-like phenotype macrophages (M2-like) in the infarcted heart of mutant mice. Further qPCR analyses showed that BDNFMet/Met peritoneal macrophages are more pro-inflammatory and have a higher migratory ability compared to BDNFVal/Val ones. Finally, macrophages differentiated from circulating monocytes isolated from BDNFMet/Met patients with coronary heart disease displayed the same pro-inflammatory characteristics of the murine ones. In conclusion, the BDNF Val66Met polymorphism predisposes to adverse cardiac remodeling after myocardial infarction in a mouse model and affects macrophage phenotype in both humans and mice. These results provide a new cellular mechanism by which this human BDNF genetic variant could influence cardiovascular disease.

Reactive oxygen species (ROS) induce nuclear factor erythroid 2–related factor 2 (Nrf2) activation as an adaptive defense mechanism, determining the synthesis of antioxidant molecules, including heme-oxygenase-1 (HO-1). HO-1 protects cells against oxidative injury, degrading free heme and inhibiting ROS production. HO-1 is highly expressed in macrophages during plaque growth. Macrophages are morpho-functionally heterogeneous, and the prevalence of a specific phenotype may influence the plaque fate. This heterogeneity has also been observed in monocyte-derived macrophages (MDMs), a model of macrophages infiltrating tissue. The study aims to assess oxidative stress status and Nrf2/HO-1 axis in MDM morphotypes obtained from healthy subjects and coronary artery disease (CAD) patients, in relation to coronary plaque features evaluated in vivo by optical coherence tomography (OCT). We found that MDMs of healthy subjects exhibited a lower oxidative stress status, lower Nrf2 and HO-1 levels as compared to CAD patients. High HO-1 levels in MDMs were associated with the presence of a higher macrophage content, a thinner fibrous cap, and a ruptured plaque with thrombus formation, detected by OCT analysis. These findings suggest the presence of a relationship between in vivo plaque characteristics and in vitro MDM profile, and may help to identify patients with rupture-prone coronary plaque.