Adult c-kit(pos) cardiac stem cells are necessary and sufficient for functional cardiac regeneration and repair.

The epidemic of heart failure has stimulated interest in understanding cardiac regeneration. Evidence has been reported supporting regeneration via transplantation of multiple cell types, as well as replication of postmitotic cardiomyocytes. In addition, the adult myocardium harbors endogenous c-kit(pos) cardiac stem cells (eCSCs), whose relevance for regeneration is controversial. Here, using different rodent models of diffuse myocardial damage causing acute heart failure, we show that eCSCs restore cardiac function by regenerating lost cardiomyocytes. Ablation of the eCSC abolishes regeneration and functional recovery. The regenerative process is completely restored by replacing the ablated eCSCs with the progeny of one eCSC. eCSCs recovered from the host and recloned retain their regenerative potential in vivo and in vitro. After regeneration, selective suicide of these exogenous CSCs and their progeny abolishes regeneration, severely impairing ventricular performance. These data show that c-kit(pos) eCSCs are necessary and sufficient for the regeneration and repair of myocardial damage.

Role of the Epigenome in Heart Failure.

Gene expression is needed for the maintenance of heart function under normal conditions and in response to stress. Each cell type of the heart has a specific program controlling transcription. Different types of stress induce modifications of these programs and, if prolonged, can lead to altered cardiac phenotype and, eventually, to heart failure. The transcriptional status of a gene is regulated by the epigenome, a complex network of DNA and histone modifications. Until a few years ago, our understanding of the role of the epigenome in heart disease was limited to that played by histone deacetylation. But over the last decade, the consequences for the maintenance of homeostasis in the heart and for the development of cardiac hypertrophy of a number of other modifications, including DNA methylation and hydroxymethylation, histone methylation and acetylation, and changes in chromatin architecture, have become better understood. Indeed, it is now clear that many levels of regulation contribute to defining the epigenetic landscape required for correct cardiomyocyte function, and that their perturbation is responsible for cardiac hypertrophy and fibrosis. Here, we review these aspects and draw a picture of what epigenetic modification may imply at the therapeutic level for heart failure.

Cardiac Aging Is Promoted by Pseudohypoxia Increasing p300-Induced Glycolysis.

BACKGROUND: Heart failure is typical in the elderly. Metabolic remodeling of cardiomyocytes underlies inexorable deterioration of cardiac function with aging: glycolysis increases at the expense of oxidative phosphorylation, causing an energy deficit contributing to impaired contractility. Better understanding of the mechanisms of this metabolic switching could be critical for reversing the condition. METHODS: To investigate the role of 3 histone modifications (H3K27ac, H3K27me3, and H3K4me1) in the metabolic remodeling occurring in the aging heart, we cross-compared epigenomic, transcriptomic, and metabolomic data from mice of different ages. In addition, the role of the transcriptional coactivator p300 (E1A-associated binding protein p300)/CBP (CREB binding protein) in cardiac aging was investigated using a specific inhibitor of this histone acetyltransferase enzyme. RESULTS: We report a set of species-conserved enhancers associated with transcriptional changes underlying age-related metabolic remodeling in cardiomyocytes. Activation of the enhancer region of Hk2-a key glycolysis pathway gene-was fostered in old age-onset mouse heart by pseudohypoxia, wherein hypoxia-related genes are expressed under normal O2 levels, via increased activity of P300/CBP. Pharmacological inhibition of this transcriptional coactivator before the onset of cardiac aging led to a more aerobic, less glycolytic, metabolic state, improved heart contractility, and overall blunting of cardiac decline. CONCLUSIONS: Taken together, our results suggest how epigenetic dysregulation of glycolysis pathway enhancers could potentially be targeted to treat heart failure in the elderly.

Single-Cell RNA Sequencing Reveals Metabolic Stress-Dependent Activation of Cardiac Macrophages in a Model of Dyslipidemia-Induced Diastolic Dysfunction.

BACKGROUND: Metabolic distress is often associated with heart failure with preserved ejection fraction (HFpEF) and represents a therapeutic challenge. Metabolism-induced systemic inflammation links comorbidities with HFpEF. How metabolic changes affect myocardial inflammation in the context of HFpEF is not known. METHODS: We found that ApoE knockout mice fed a Western diet recapitulate many features of HFpEF. Single-cell RNA sequencing was used for expression analysis of CD45+ cardiac cells to evaluate the involvement of inflammation in diastolic dysfunction. We focused bioinformatics analysis on macrophages, obtaining high-resolution identification of subsets of these cells in the heart, enabling us to study the outcomes of metabolic distress on the cardiac macrophage infiltrate and to identify a macrophage-to-cardiomyocyte regulatory axis. To test whether a clinically relevant sodium glucose cotransporter-2 inhibitor could ameliorate the cardiac immune infiltrate profile in our model, mice were randomized to receive the sodium glucose cotransporter-2 inhibitor dapagliflozin or vehicle for 8 weeks. RESULTS: ApoE knockout mice fed a Western diet presented with reduced diastolic function, reduced exercise tolerance, and increased pulmonary congestion associated with cardiac lipid overload and reduced polyunsaturated fatty acids. The main immune cell types infiltrating the heart included 4 subpopulations of resident and monocyte-derived macrophages, determining a proinflammatory profile exclusively in ApoE knockout- Western diet mice. Lipid overload had a direct effect on inflammatory gene activation in macrophages, mediated through endoplasmic reticulum stress pathways. Investigation of the macrophage-to-cardiomyocyte regulatory axis revealed the potential effects on cardiomyocytes of multiple inflammatory cytokines secreted by macrophages, affecting pathways such as hypertrophy, fibrosis, and autophagy. Finally, we describe an anti-inflammatory effect of sodium glucose cotransporter-2 inhibitor in this model. CONCLUSIONS: Using single-cell RNA sequencing , in a model of diastolic dysfunction driven by hyperlipidemia, we have determined the effects of metabolic distress on cardiac inflammatory cells, in particular on macrophages, and suggest sodium glucose cotransporter-2 inhibitors as potential therapeutic agents for the targeting of a specific phenotype of HFpEF.

Multiparametric Mapping via Cardiovascular Magnetic Resonance in the Risk Stratification of Ventricular Arrhythmias and Sudden Cardiac Death.

Risk stratification for malignant ventricular arrhythmias and sudden cardiac death is a daunting task for physicians in daily practice. Multiparametric mapping sequences obtained via cardiovascular magnetic resonance imaging can improve the risk stratification for malignant ventricular arrhythmias by unveiling the presence of pathophysiological pro-arrhythmogenic processes. However, their employment in clinical practice is still restricted. The present review explores the current evidence supporting the association between mapping abnormalities and the risk of ventricular arrhythmias in several cardiovascular diseases. The key message is that further clinical studies are needed to test the additional value of mapping techniques beyond conventional cardiovascular magnetic resonance imaging for selecting patients eligible for an implantable cardioverter defibrillator.

P2Y12 Inhibitors Monotherapy in Patients Undergoing Complex vs Non-Complex Percutaneous Coronary Intervention: A Meta-Analysis of Randomized Trials.

BACKGROUND: Monotherapy with P2Y12 inhibitors (P2Y12i) is emerging as alternative strategy to dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI). However, early withdrawal of aspirin as part of P2Y12i monotherapy regimens may pose concerns in high-risk patients, such as those undergoing complex PCI. Our aim was to evaluate the efficacy and safety of P2Y12i monotherapy after a short course of DAPT (1-3-month) compared with standard DAPT (≥12-month) according to PCI complexity. METHODS: We performed a meta-analysis of randomized trials using random effects models to combine hazard ratios (HRs) with 95% confidence intervals (CIs). Within-trial interactions were pooled to estimate heterogeneity between complex and noncomplex PCI strata. The study protocol was registered in the PROSPERO (CRD42021291027). RESULTS: We identified 5 trials including 31,627 patients, of whom 8,328 (26.3%) underwent complex PCI. P2Y12i monotherapy compared with standard DAPT was associated with a similar risk of all-cause death, stent thrombosis, and stroke, with no evidence for interaction between complex and noncomplex PCI. We found heterogeneity in the treatment effect of P2Y12i monotherapy vs standard DAPT with respect to myocardial infarction (P-interaction = 0.027). Compared with standard DAPT, P2Y12i monotherapy decreased the risk of myocardial infarction in complex PCI (HR 0.77, 95%CI 0.60-0.99, P = .042), but not in noncomplex PCI patients (HR 1.09, 95%CI 0.90-1.30, P = .382). The risk of major bleeding was significantly reduced by P2Y12i monotherapy with a consistent treatment effect (P-interaction = 0.699) in both complex and noncomplex PCI strata. CONCLUSIONS: Patients undergoing complex PCI may derive more benefit and less harm from P2Y12i monotherapy after early aspirin withdrawal compared with standard DAPT.

Integration of epigenetic regulatory mechanisms in heart failure.

The number of "omics" approaches is continuously growing. Among others, epigenetics has appeared as an attractive area of investigation by the cardiovascular research community, notably considering its association with disease development. Complex diseases such as cardiovascular diseases have to be tackled using methods integrating different omics levels, so called "multi-omics" approaches. These approaches combine and co-analyze different levels of disease regulation. In this review, we present and discuss the role of epigenetic mechanisms in regulating gene expression and provide an integrated view of how these mechanisms are interlinked and regulate the development of cardiac disease, with a particular attention to heart failure. We focus on DNA, histone, and RNA modifications, and discuss the current methods and tools used for data integration and analysis. Enhancing the knowledge of these regulatory mechanisms may lead to novel therapeutic approaches and biomarkers for precision healthcare and improved clinical outcomes.

Clinical relevance of clonal hematopoiesis in persons aged ≥80 years.

Clonal hematopoiesis of indeterminate potential (CHIP) is associated with increased risk of cancers and inflammation-related diseases. This phenomenon becomes common in persons aged ≥80 years, in whom the implications of CHIP are not well defined. We performed a mutational screening in 1794 persons aged ≥80 years and investigated the relationships between CHIP and associated pathologies. Mutations were observed in one-third of persons aged ≥80 years and were associated with reduced survival. Mutations in JAK2 and splicing genes, multiple mutations (DNMT3A, TET2, and ASXL1 with additional genetic lesions), and variant allele frequency ≥0.096 had positive predictive value for myeloid neoplasms. Combining mutation profiles with abnormalities in red blood cell indices improved the ability of myeloid neoplasm prediction. On this basis, we defined a predictive model that identifies 3 risk groups with different probabilities of developing myeloid neoplasms. Mutations in DNMT3A, TET2, ASXL1, or JAK2 were associated with coronary heart disease and rheumatoid arthritis. Cytopenia was common in persons aged ≥80 years, with the underlying cause remaining unexplained in 30% of cases. Among individuals with unexplained cytopenia, the presence of highly specific mutation patterns was associated with myelodysplastic-like phenotype and a probability of survival comparable to that of myeloid neoplasms. Accordingly, 7.5% of subjects aged ≥80 years with cytopenia had presumptive evidence of myeloid neoplasm. In summary, specific mutational patterns define different risk of developing myeloid neoplasms vs inflammatory-associated diseases in persons aged ≥80 years. In individuals with unexplained cytopenia, mutational status may identify those subjects with presumptive evidence of myeloid neoplasms.

Safety of metformin continuation in diabetic patients undergoing invasive coronary angiography: the NO-STOP single arm trial.

BACKGROUND: Despite paucity of data, it is common practice to discontinue metformin before invasive coronary angiography due to an alleged risk of Metformin-Associated Lactic Acidosis (M-ALA). We aimed at assessing the safety of metformin continuation in diabetic patients undergoing coronary angiography in terms of significant increase in lactate levels. METHODS: In this open-label, prospective, multicentre, single-arm trial, all diabetic patients undergoing coronary angiography with or without percutaneous coronary intervention at 3 European centers were screened for enrolment. The primary endpoint was the increase in lactate levels from preprocedural levels at 72-h after the procedure. Secondary endpoints included contrast associated-acute kidney injury (CA-AKI), M-ALA, and all-cause mortality. RESULTS: 142 diabetic patients on metformin therapy were included. Median preprocedural lactate level was 1.8 mmol/l [interquartile range (IQR) 1.3-2.3]. Lactate levels at 72 h after coronary angiography were 1.7 mmol/l (IQR 1.3-2.3), with no significant differences as compared to preprocedural levels (p = 0.91; median difference = 0; IQR - 0.5 to 0.4 mmol/l). One patient had 72-h levels ≥ 5 mmol/l (5.3 mmol/l), but no cases of M-ALA were reported. CA-AKI occurred in 9 patients (6.1%) and median serum creatinine and estimated glomerular filtration rate remained similar throughout the periprocedural period. At a median follow-up of 90 days (43-150), no patients required hemodialysis and 2 patients died due to non-cardiac causes. CONCLUSIONS: In diabetic patients undergoing invasive coronary angiography, metformin continuation throughout the periprocedural period does not increase lactate levels and was not associated with any decline in renal function. TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov (NCT04766008).

Clinical and procedural outcomes of percutaneous coronary intervention for de novo lesions involving the ostial left circumflex coronary artery.

BACKGROUND: Percutaneous treatment for ostial left circumflex artery (LCx) lesions is known to be associated with suboptimal results. AIMS: The present study aims to assess the procedural and long-term clinical outcomes of percutaneous coronary intervention (PCI) for de novo ostial LCx lesions overall and according to the coronary revascularization strategy. METHODS: Consecutive patients undergoing PCI with second generation drug eluting stents or drug coated balloons for de novo ostial LCx lesions in three high-volume Italian centers between 2012 and 2021 were retrospectively evaluated. The primary endpoint was target-vessel revascularization (TVR) at 2 years. Secondary endpoints included major adverse cardiovascular and cerebrovascular events (MACCE), target lesion revascularization, myocardial infarction, stroke, all-cause death, and repeat revascularization. RESULTS: A total of 366 patients were included in the analysis with a median follow-up of 901 (IQR: 450-1728) days. 79.5% of the patients were male, 33.6% were diabetic, 49.7% had a previous PCI, and 23.1% a prior surgical revascularization. Very ostial LCx stenting was performed in 34.1%, crossover from left main to LCx in 17.3%, and a two-stent strategy in 48.6% of cases, respectively. In the overall population, the incidence of TVR at 2 years was 19.0% while MACCE rate was 25.7%. No major differences in clinical outcomes were found according to the stenting strategy. Use of intracoronary imaging was associated with fewer MACCE (HR: 0.47, 95% CI: 0.25-1.13, p = 0.01), while the diameter of the stent implanted in the ostial LCx was associated with less TVR (HR: 0.43, 95% CI: 0.25-0.75, p = 0.002). CONCLUSIONS: Percutaneous revascularization of the ostial LCx is associated with a high rate of TVR, regardless of the stenting strategy. Intracoronary imaging and proper stent sizing may reduce the failure rates.

Role of Reticulated Platelets in Cardiovascular Disease.

Human platelets differ considerably with regard to their size, RNA content and thrombogenicity. Reticulated platelets (RPs) are young, hyper-reactive platelets that are newly released from the bone marrow. They are larger and contain more RNA compared to older platelets. In comparison to more mature platelets, they exhibit a significantly higher thrombogenicity and are known to be elevated in patients with an increased platelet turnover such as, diabetics and after acute myocardial infarction. Several studies have shown that RPs correlate with an insufficient antiplatelet response to aspirin and specific P2Y12 receptor inhibitors. In addition, RPs are promising novel biomarkers for the prediction of adverse cardiovascular events in cardiovascular disease. However, the reason for RPs intrinsic hyper-reactivity and their association with ischemic events is not completely understood and the biology of RPs is still under investigation. We here present a structured review of preclinical and clinical findings concerning the role of RPs in cardiovascular disease.

Atrial arrhythmias and heart failure: A "modern view" of an old paradox.

BACKGROUND: Heart failure (HF) and atrial arrhythmias (AAs) are two clinical conditions that characterize the daily clinical practice of cardiologists. In this perspective review, we analyze the shared etiopathogenetic pathways of atrial arrhythmias, which are the most common cause of atrial arrhythmias-induced cardiomyopathy (AACM) and HF. HYPOTHESIS: The aim is to explore the pathophysiology of these two conditions considering them as a "unicum", allowing the definition of a cardiovascular continuum where it is possible to predict the factors and to identify the patient phenotype most at risk to develop HF due to atrial arrhythmias. METHODS: Potentially eligible articles, identified from the Electronic database (PubMed), and related references were used for a literature search that was conducted between January 2022 and January 2023. Search strategies were designed to identify articles that reported atrial arrhythmias in association with heart failure and vice versa. For the search we used the following keywords: atrial arrhythmias, atrial fibrillation, heart failure, arrhythmia-induced cardiomyopathy, tachycardiomyopathy. We identified 620 articles through the electronic database search. Out of the 620 total articles we removed 320 duplicates, thus selecting 300 eligible articles. About 150 titles/abstracts were excluded for the following reasons: no original available data, no mention of atrial arrhythmias and heart failure crosstalk, very low quality analysis or evidence. We excluded also non-English articles. When multiple articles were published on the same topic, the articles with the most complete set of data were considered. We preferentially included all papers that could provide the best evidence in the field. As a result, the present review article is based on a final number of 104 references. RESULTS: While the pathophysiology of AACM and Heart Failure with reduced ejection fraction (HFrEF) has been studied in detail over the years, the causal link between atrial arrhythmias and heart failure with Preserved Ejection Fraction (HFpEF) has been often subject of interest. HFpEF is strictly related to AAs, which has always been considered significant risk factor. In this review we described the pathophysiological links between atrial fibrillation and heart failure. Furthermore, we illustrated and discussed the preclinical and clinical predicting factors of AF and HFpEF, and the corresponding targets of the available therapeutic agents. Finally, we outlined the patient phenotype at risk of developing AF and HFpEF (Central Illustration). CONCLUSIONS: In this review, we underline how these two clinical conditions (AF and HFpEF) represent a "unicum" and, therefore, should be considered as a single disease that can manifest itself in the same phenotype of patients but at different times. Furthermore, considering that today we have few therapeutic strategies to treat these patients, it would be good to make an early diagnosis in the initial stages of the disease or intervene even before the development of signs and symptoms of HF. This is possible only by paying greater attention to patients with predisposing factors and carrying out a targeted screening with the correct diagnostic methods. A systemic approach aimed at improving the immuno-metabolic profile of these patients by lowering the body mass index, threatening the predisposing factors, lowering the mean heart rate and reducing the sympathetic nervous system activation is the key strategy to reduce the clinical impact of this disease.

Long-term prognostic impact of subclinical myocardial dysfunction in patients recovered from COVID-19.

BACKGROUND: Cardiovascular sequelae may occur in patients recovered from coronavirus disease 2019 (COVID-19). Recent studies have detected a considerable incidence of subclinical myocardial dysfunction-assessed with speckle-tracking echocardiography-and of long-COVID symptoms in these patients. This study aimed to define the long-term prognostic role of subclinical myocardial dysfunction and long-COVID condition in patients recovered from COVID-19 pneumonia. METHODS: We prospectively followed up 110 patients hospitalized at our institution due to COVID-19 pneumonia in April 2020 and then recovered from SARS-CoV-2 infection. A 7-month clinical and echocardiographic evaluation was performed, followed by a 21-month clinical follow-up. The primary outcome was major adverse cardiovascular events (MACE), a composite of myocardial infarction, stroke, heart failure hospitalization, and all-cause mortality. RESULTS: A subclinical myocardial dysfunction-defined as an impairment of left ventricular global longitudinal strain (≥-18%)-was identified at a 7-month follow-up in 37 patients (34%), was associated with an increased risk of long-term MACE with a good discriminative power (area under the curve: .73) and resulted in a strong independent predictor of extended MACE in multivariate regression analyses. Long-COVID condition was not associated with a worse long-term prognosis, instead. CONCLUSIONS: In patients recovered from COVID-19 pneumonia, a subclinical myocardial dysfunction is present in one-third of the whole population at 7-month follow-up and is associated with a higher risk of MACE at long-term follow-up. Speckle-tracking echocardiography is a promising tool to optimize the risk-stratification in patients recovered from COVID-19 pneumonia, while the definition of a long-COVID condition has no prognostic relevance.

The epigenetic enzyme DOT1L orchestrates vascular smooth muscle cell-monocyte crosstalk and protects against atherosclerosis via the NF-κB pathway.

AIMS: Histone H3 dimethylation at lysine 79 is a key epigenetic mark uniquely induced by methyltransferase disruptor of telomeric silencing 1-like (DOT1L). We aimed to determine whether DOT1L modulates vascular smooth muscle cell (VSMC) phenotype and how it might affect atherosclerosis in vitro and in vivo, unravelling the related mechanism. METHODS AND RESULTS: Gene expression screening of VSMCs stimulated with the BB isoform of platelet-derived growth factor led us to identify Dot1l as an early up-regulated epigenetic factor. Mouse and human atherosclerotic lesions were assessed for Dot1l expression, which resulted specifically localized in the VSMC compartment. The relevance of Dot1l to atherosclerosis pathogenesis was assessed through deletion of its gene in the VSMCs via an inducible, tissue-specific knock-out mouse model crossed with the ApoE-/- high-fat diet model of atherosclerosis. We found that the inactivation of Dot1l significantly reduced the progression of the disease. By combining RNA- and H3K79me2-chromatin immunoprecipitation-sequencing, we found that DOT1L and its induced H3K79me2 mark directly regulate the transcription of Nf-κB-1 and -2, master modulators of inflammation, which in turn induce the expression of CCL5 and CXCL10, cytokines fundamentally involved in atherosclerosis development. Finally, a correlation between coronary artery disease and genetic variations in the DOT1L gene was found because specific polymorphisms are associated with increased mRNA expression. CONCLUSION: DOT1L plays a key role in the epigenetic control of VSMC gene expression, leading to atherosclerosis development. Results identify DOT1L as a potential therapeutic target for vascular diseases.

Myeloid-Derived Growth Factor Protects Against Pressure Overload-Induced Heart Failure by Preserving Sarco/Endoplasmic Reticulum Ca2+-ATPase Expression in Cardiomyocytes.

BACKGROUND: Inflammation contributes to the pathogenesis of heart failure, but there is limited understanding of inflammation's potential benefits. Inflammatory cells secrete MYDGF (myeloid-derived growth factor) to promote tissue repair after acute myocardial infarction. We hypothesized that MYDGF has a role in cardiac adaptation to persistent pressure overload. METHODS: We defined the cellular sources and function of MYDGF in wild-type (WT), Mydgf-deficient (Mydgf-/-), and Mydgf bone marrow-chimeric or bone marrow-conditional transgenic mice with pressure overload-induced heart failure after transverse aortic constriction surgery. We measured MYDGF plasma concentrations by targeted liquid chromatography-mass spectrometry. We identified MYDGF signaling targets by phosphoproteomics and substrate-based kinase activity inference. We recorded Ca2+ transients and sarcomere contractions in isolated cardiomyocytes. Additionally, we explored the therapeutic potential of recombinant MYDGF. RESULTS: MYDGF protein abundance increased in the left ventricular myocardium and in blood plasma of pressure-overloaded mice. Patients with severe aortic stenosis also had elevated MYDGF plasma concentrations, which declined after transcatheter aortic valve implantation. Monocytes and macrophages emerged as the main MYDGF sources in the pressure-overloaded murine heart. While Mydgf-/- mice had no apparent phenotype at baseline, they developed more severe left ventricular hypertrophy and contractile dysfunction during pressure overload than WT mice. Conversely, conditional transgenic overexpression of MYDGF in bone marrow-derived inflammatory cells attenuated pressure overload-induced hypertrophy and dysfunction. Mechanistically, MYDGF inhibited G protein-coupled receptor agonist-induced hypertrophy and augmented SERCA2a (sarco/endoplasmic reticulum Ca2+-ATPase 2a) expression in cultured neonatal rat ventricular cardiomyocytes by enhancing PIM1 (Pim-1 proto-oncogene, serine/threonine kinase) expression and activity. Along this line, cardiomyocytes from pressure-overloaded Mydgf-/- mice displayed reduced PIM1 and SERCA2a expression, greater hypertrophy, and impaired Ca2+ cycling and sarcomere function compared with cardiomyocytes from pressure-overloaded WT mice. Transplanting Mydgf-/- mice with WT bone marrow cells augmented cardiac PIM1 and SERCA2a levels and ameliorated pressure overload-induced hypertrophy and dysfunction. Pressure-overloaded Mydgf-/- mice were similarly rescued by adenoviral Serca2a gene transfer. Treating pressure-overloaded WT mice subcutaneously with recombinant MYDGF enhanced SERCA2a expression, attenuated left ventricular hypertrophy and dysfunction, and improved survival. CONCLUSIONS: These findings establish a MYDGF-based adaptive crosstalk between inflammatory cells and cardiomyocytes that protects against pressure overload-induced heart failure.

Left atrial appendage closure with the II generation Ultraseal device: An international registry. The LIGATE study.

OBJECTIVES: To assess feasibility and safety of second-generation left atrial appendage closure (LAAC) Ultraseal device in patients with nonvalvular atrial fibrillation (NVAF). BACKGROUND: LAAC with first-generation Ultraseal device (Cardia, Eagan, Minnesota) has been shown to be a feasible therapeutic option in patients with NVAF. However, there is a paucity of data regarding the novel second-generation Ultraseal device. METHODS: All patients with NVAF undergoing second-generation Ultraseal device implantation between February 2018 and September 2020 were included in a multicenter international registry. Periprocedural and post-discharge events were collected through 6-month follow-up. Co-primary efficacy endpoints were device success and technical success while primary safety endpoint was in-hospital major adverse event (MAE) occurrence. RESULTS: A total of 52 patients were included: mean age 75 ± 8, 30.8% women, mean HAS-BLED 3 ± 1. The device was successfully implanted in all patients. Technical success was achieved in 50 patients (96.1%). In-hospital MAEs occurred in three patients (5.8%). The incidence of 6-month all-cause death and major bleeding was 11.6% and 2.1%, respectively. No strokes, transient ischemic attacks, systemic embolisms, or device embolization were reported after discharge. CONCLUSIONS: Second-generation Ultraseal device implantation was associated with high success rates and a low incidence of peri-procedural complications. Larger studies with longer follow-up are warranted to further evaluate the safety and the efficacy of this device, especially at long-term follow-up.

miR-128-3p Is a Novel Regulator of Vascular Smooth Muscle Cell Phenotypic Switch and Vascular Diseases.

RATIONALE: MicroRNAs (miRNAs, miRs) are small noncoding RNAs that modulate gene expression by negatively regulating translation of target genes. Although the role of several miRNAs in vascular smooth muscle cells (VSMCs) has been extensively characterized, the function of miRNA-128-3p (miR-128) is still unknown. OBJECTIVE: To determine if miR-128 modulates VSMC phenotype and to define the underlying mechanisms. METHODS AND RESULTS: We screened for miRNAs whose expression is modulated by an altered DNA methylation status in VSMCs, and among the hits, we selected miR-128. We found that miR-128 was expressed in various tissues, primary murine cells, and pathological murine and human vascular specimens. Through gain- and loss-of-function approaches, we determined that miR-128 affects VSMC proliferation, migration, differentiation, and contractility. The alterations of those properties were dependent upon epigenetic regulation of key VSMC differentiation genes; notably, Kruppel-like factor 4 was found to be a direct target of miR-128 and able to modulate the methylation status of the pivotal VSMC gene myosin heavy chain 11 (Myh11). Finally, in vivo lentiviral delivery of miR-128 prevented intimal hyperplasia in a mouse model of carotid restenosis without modifying vital cardiovascular parameters. CONCLUSION: miR-128 is a critical modulator of VSMCs and is regulated by epigenetic modifications upon stress. Its modulation in the context of disease could be exploited for therapeutic purposes.

Biochemical Efficacy of Sodium-Glucose Cotransporter 2 Inhibitors by Cardiovascular Risk Profile and Volume Status in a Real-World Diabetic Population.

ABSTRACT: Despite large-scale randomized clinical trials (RCTs) highlighting a consistent prognostic benefit of sodium-glucose cotransporter 2 inhibitors (SGLT2is) both in diabetic patients at high cardiovascular risk and in those with heart failure, there is relative paucity of data on their biochemical effects in a real-world setting. We performed a retrospective analysis on consecutive diabetic patients who were prescribed a SGLT2i in a tertiary referral center and completed at least 1 year of treatment. Changes in glycated hemoglobin, weight, and hematocrit were compared across 2 cardiovascular risk categories, defined through the inclusion criteria of 3 large RCTs. Of the 459 patients screened, 312 completed 1 year of treatment (68.0%), 92 interrupted the treatment prematurely (20.0%), and 55 were lost to follow-up (12.0%). The most common cause of drug discontinuation was genital or urinary tract infections (9.4%). At 1 year, reduction in glycated hemoglobin concentration (-0.7 ± 1.5%, P < 0.001) and body weight (2.4 ± 4.6 kg, P < 0.001) was comparable between patients at high versus low cardiovascular risk, while hematocrit increase (2.3 ± 3.3%, P < 0.001) was more marked in patients with high cardiovascular risk and low baseline hematocrit. In a real-world population of diabetic patients, SGLT2is were well-tolerated at 1 year and led to improved glycemic control and weight loss. Hematocrit increase was more consistent in patients with high cardiovascular risk and signs of fluid overload, indicating euvolemic restoration as a potential cardioprotective mechanism mediated by these compounds.

Mass cytometry of platelet-rich plasma: a new approach to analyze platelet surface expression and reactivity.

Mass cytometry (CyTOF) is a new technology that allows the investigation of protein expression at single cell level with high resolution. While several protocols are available to investigate leukocyte expression, platelet staining and analysis with CyTOF have been described only from whole blood. Moreover, available protocols do not allow sample storage but require fresh samples to be obtained, processed, and measured immediately. We provide a structured and reproducible method to stain platelets from platelet-rich plasma to study thrombocyte protein expression and reactivity using mass cytometry. With our method, it is possible to acquire a large number of events allowing deep bioinformatic investigation of platelet expression heterogeneity. Integrated in our protocol is also a previously established freezing protocol that allows the storage of stained samples and to delay their measurement. Finally, we provide a structured workflow using different platelet stimulators and a freely available bioinformatic pipeline to analyze platelet expression. Our protocol unlocks the potential of CyTOF analysis for studying platelet biology in health and disease.

Myocardial hypoxic stress mediates functional cardiac extracellular vesicle release.

AIMS: Increased shedding of extracellular vesicles (EVs)-small, lipid bilayer-delimited particles with a role in paracrine signalling-has been associated with human pathologies, e.g. atherosclerosis, but whether this is true for cardiac diseases is unknown. METHODS AND RESULTS: Here, we used the surface antigen CD172a as a specific marker of cardiomyocyte (CM)-derived EVs; the CM origin of CD172a+ EVs was supported by their content of cardiac-specific proteins and heart-enriched microRNAs. We found that patients with aortic stenosis, ischaemic heart disease, or cardiomyopathy had higher circulating CD172a+ cardiac EV counts than did healthy subjects. Cellular stress was a major determinant of EV release from CMs, with hypoxia increasing shedding in in vitro and in vivo experiments. At the functional level, EVs isolated from the supernatant of CMs derived from human-induced pluripotent stem cells and cultured in a hypoxic atmosphere elicited a positive inotropic response in unstressed CMs, an effect we found to be dependent on an increase in the number of EVs expressing ceramide on their surface. Of potential clinical relevance, aortic stenosis patients with the highest counts of circulating cardiac CD172a+ EVs had a more favourable prognosis for transcatheter aortic valve replacement than those with lower counts. CONCLUSION: We identified circulating CD172a+ EVs as cardiac derived, showing their release and function and providing evidence for their prognostic potential in aortic stenosis patients.