851 research outputs found

    MicroRNA-24 regulates vascularity after myocardial infarction

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    BACKGROUND: Myocardial infarction leads to cardiac remodeling and development of heart failure. Insufficient myocardial capillary density after myocardial infarction has been identified as a critical event in this process, although the underlying mechanisms of cardiac angiogenesis are mechanistically not well understood. METHODS AND RESULTS: Here, we show that the small noncoding RNA microRNA-24 (miR-24) is enriched in cardiac endothelial cells and considerably upregulated after cardiac ischemia. MiR-24 induces endothelial cell apoptosis, abolishes endothelial capillary network formation on Matrigel, and inhibits cell sprouting from endothelial spheroids. These effects are mediated through targeting of the endothelium-enriched transcription factor GATA2 and the p21-activated kinase PAK4, which were identified by bioinformatic predictions and validated by luciferase gene reporter assays. Respective downstream signaling cascades involving phosphorylated BAD (Bcl-XL/Bcl-2-associated death promoter) and Sirtuin1 were identified by transcriptome, protein arrays, and chromatin immunoprecipitation analyses. Overexpression of miR-24 or silencing of its targets significantly impaired angiogenesis in zebrafish embryos. Blocking of endothelial miR-24 limited myocardial infarct size of mice via prevention of endothelial apoptosis and enhancement of vascularity, which led to preserved cardiac function and survival. CONCLUSIONS: Our findings indicate that miR-24 acts as a critical regulator of endothelial cell apoptosis and angiogenesis and is suitable for therapeutic intervention in the setting of ischemic heart disease. [KEYWORDS: Animals, Apoptosis/drug effects, Arterioles/pathology, Capillaries/pathology, Cell Hypoxia, Cells, Cultured/drug effects/metabolism, Collagen, Drug Combinations, Drug Evaluation, Preclinical, Endothelial Cells/ metabolism/pathology, GATA2 Transcription Factor/biosynthesis/genetics, Gene Expression Profiling, Heart Failure/etiology, Heme Oxygenase-1/biosynthesis/genetics, Laminin, Male, Mice, Mice, Inbred C57BL, MicroRNAs/antagonists & inhibitors/genetics/ physiology, Myocardial Infarc

    Uterine NK cells are critical in shaping DC immunogenic functions compatible with pregnancy progression.

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    Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression

    Exercise training improves vascular mitochondrial function

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    Exercise training is recognized to improve cardiac and skeletal muscle mitochondrial respiratory capacity; however, the impact of chronic exercise on vascular mitochondrial respiratory function is unknown. We hypothesized that exercise training concomitantly increases both vascular mitochondrial respiratory capacity and vascular function. Arteries from both sedentary (SED) and swim-trained (EX, 5 wk) mice were compared in terms of mitochondrial respiratory function, mitochondrial content, markers of mitochondrial biogenesis, redox balance, nitric oxide (NO) signaling, and vessel function. Mitochondrial complex I and complex I + II state 3 respiration and the respiratory control ratio (complex I + II state 3 respiration/complex I state 2 respiration) were greater in vessels from EX relative to SED mice, despite similar levels of arterial citrate synthase activity and mitochondrial DNA content. Furthermore, compared with the SED mice, arteries from EX mice displayed elevated transcript levels of peroxisome proliferative activated receptor-γ coactivator-1α and the downstream targets cytochrome c oxidase subunit IV isoform 1, isocitrate dehydrogenase (Idh) 2, and Idh3a, increased manganese superoxide dismutase protein expression, increased endothelial NO synthase phosphorylation (Ser1177), and suppressed reactive oxygen species generation (all P \u3c 0.05). Although there were no differences in EX and SED mice concerning endothelium-dependent and endothelium-independent vasorelaxation, phenylephrine-induced vasocontraction was blunted in vessels from EX compared with SED mice, and this effect was normalized by NOS inhibition. These training-induced increases in vascular mitochondrial respiratory capacity and evidence of improved redox balance, which may, at least in part, be attributable to elevated NO bioavailability, have the potential to protect against age- and disease-related challenges to arterial function

    Left ventricular remodelling post-myocardial infarction: pathophysiology, imaging, and novel therapies

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    Most patients survive acute myocardial infarction (MI). Yet this encouraging development has certain drawbacks: heart failure (HF) prevalence is increasing and patients affected tend to have more comorbidities worsening economic strain on healthcare systems and impeding effective medical management. The heart's pathological changes in structure and/or function, termed myocardial remodelling, significantly impact on patient outcomes. Risk factors like diabetes, chronic obstructive pulmonary disease, female sex, and others distinctly shape disease progression on the 'road to HF'. Despite the availability of HF drugs that interact with general pathways involved in myocardial remodelling, targeted drugs remain absent, and patient risk stratification is poor. Hence, in this review, we highlight the pathophysiological basis, current diagnostic methods and available treatments for cardiac remodelling following MI. We further aim to provide a roadmap for developing improved risk stratification and novel medical and interventional therapies

    Sacubitril/valsartan in heart failure: efficacy and safety in and outside clinical trials.

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    Heart failure (HF) treatment has changed substantially over the last 30 years, leading to significant reductions in mortality and hospital admissions in patients with HF with reduced ejection fraction (HFrEF). Currently, the optimization of guideline-directed chronic HF therapy remains the mainstay to further improve quality of life, mortality, and HF hospitalizations for patients with HFrEF. The angiotensin receptor-neprilysin inhibitor sacubitril/valsartan (S/V) has an important role in the treatment of patients with HFrEF. The PARADIGM-HF (Prospective Comparison of ARNI with ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure) randomized controlled trial has established solid evidence for the treatment of HFrEF in various subgroups. Apart from HFrEF, several studies have been conducted using S/V in various indications: patients hospitalized with acute decompensated HF, HF with preserved ejection fraction, acute myocardial infarction with reduced ejection fraction, uncontrolled and resistant hypertension, and chronic kidney disease. Data from the German Institute for Drug Use Evaluation reveal that implementation of S/V has increased steadily over time and, by the end of 2021, an estimated 266 000 patients were treated with S/V in Germany. The estimated cumulative real-world patient exposure is >5.5 million patient-treatment years worldwide. The number of patients treated with S/V largely exceeds the number of patients treated in clinical trials, and the current indication for S/V is larger than the strict inclusion/exclusion criteria of the randomized trials. Especially elderly patients, women, and patients with more and more severe comorbidities are underrepresented in the clinical trials. We therefore aimed to summarize the importance of S/V in HF in terms of efficacy and safety in clinical trials and daily clinical practice

    Management of Worsening Heart Failure With Reduced Ejection Fraction:<i>JACC </i>Focus Seminar 3/3

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    Despite worsening heart failure (HF) being extremely common, expensive, and associated with substantial risk of death, there remain no dedicated clinical practice guidelines for the specific management of these patients. The lack of a management guideline is despite a rapidly evolving evidence-base, as a number of recent clinical trials have demonstrated multiple therapies to be safe and efficacious in this high-risk population. Herein, we propose a framework for treating worsening HF with reduced ejection fraction with the sense of urgency it deserves. This includes treating congestion; managing precipitants; and establishing a foundation of rapid-sequence, simultaneous, and/or in-hospital initiation of quadruple medical therapy for HF with reduced ejection fraction, with the top priority being at least low doses of all 4 medications. Moreover, to maximally reduce residual clinical risk, we further propose consideration of upfront simultaneous use of vericiguat (ie, quintuple medical therapy) and administration of intravenous iron for those who are iron deficient.</p
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