Growth hormone-releasing hormone attenuates cardiac hypertrophy and improves heart function in pressure overload-induced heart failure

It has been shown that growth hormone-releasing hormone (GHRH) reduces cardiomyocyte (CM) apoptosis, prevents ischemia/reperfusion injury, and improves cardiac function in ischemic rat hearts. However, it is still not known whether GHRH would be beneficial for life-threatening pathological conditions, like cardiac hypertrophy and heart failure (HF). Thus, we tested the myocardial therapeutic potential of GHRH stimulation in vitro and in vivo, using GHRH or its agonistic analog MR-409. We show that in vitro, GHRH(1-44)NH2attenuates phenylephrine-induced hypertrophy in H9c2 cardiac cells, adult rat ventricular myocytes, and human induced pluripotent stem cell-derived CMs, decreasing expression of hypertrophic genes and regulating hypertrophic pathways. Underlying mechanisms included blockade of Gq signaling and its downstream components phospholipase Cβ, protein kinase Ce, calcineurin, and phospholamban. The receptor-dependent effects of GHRH also involved activation of Gαsand cAMP/PKA, and inhibition of increase in exchange protein directly activated by cAMP1 (Epac1). In vivo, MR-409 mitigated cardiac hypertrophy in mice subjected to transverse aortic constriction and improved cardiac function. Moreover, CMs isolated from transverse aortic constriction mice treated with MR-409 showed improved contractility and reversal of sarcolemmal structure. Overall, these results identify GHRH as an antihypertrophic regulator, underlying its therapeutic potential for HF, and suggest possible beneficial use of its analogs for treatment of pathological cardiac hypertrophy

Parallel Lineage-Tracing Studies Establish Fibroblasts as the Prevailing In Vivo Adipocyte Progenitor.

Summary: Despite decades of studies suggesting that the in vivo adipocyte progenitor resides within the vascular niche, the exact nature of this progenitor remains controversial because distinct studies have attributed adipogenic properties to multiple vascular cell types. Using Cre recombinases labeling distinct vascular lineages, we conduct parallel lineage tracing experiments to assess their degree of contribution to de novo adipogenesis. Although we detect occasional adipocytes that were lineage traced by endothelial or mural recombinases, these are rare events. On the other hand, platelet-derived growth factor receptor alpha (PDGFRα)-expressing adventitial or capsular fibroblasts make a significant contribution to adipocytes in all depots and experimental settings tested. Our data also suggest that fibroblasts transition to an intermediate beige adipocyte phenotype prior to differentiating to a mature white adipocyte. These observations, together with histological analyses revealing that adipose tissue fibroblasts express the mural cell marker PDGFRβ, harmonize a highly controversial field with implications for multiple human diseases, including the pandemic of obesity. : Cattaneo et al. used genetic fate mapping in murine models to test the adipogenic potential of distinct cell types of the vascular wall. These parallel lineage-tracing experiments reveal that fibroblasts are the sole vascular cell type with significant adipocyte progenitor activity, giving rise to brown, beige, and white adipocytes. Keywords: adipogenesis, obesity, vascular wall, lineage tracing, endothelium, mural cells, fibroblast

Dietary essential amino acids for the treatment of heart failure with reduced ejection fraction

Aims: Heart failure with reduced ejection fraction (HFrEF) is a leading cause of mortality worldwide, requiring novel therapeutic and lifestyle interventions. Metabolic alterations and energy production deficit are hallmarks and thereby promising therapeutic targets for this complex clinical syndrome. We aim to study the molecular mechanisms and effects on cardiac function in rodents with HFrEF of a designer diet in which free essential amino acids - in specifically designed percentages - substituted for protein. Methods and results: Wild-type mice were subjected to transverse aortic constriction (TAC) to induce left ventricle (LV) pressure overload or sham surgery. Whole body glucose homeostasis was studied with glucose tolerance test, while myocardial dysfunction and fibrosis were measured with echocardiogram and histological analysis. Mitochondrial bioenergetics and morphology were investigated with oxygen consumption rate measurement and electron microscopy evaluation. Circulating and cardiac non-targeted metabolite profiles were analyzed by ultrahigh performance liquid chromatography-tandem mass spectroscopy, while RNA sequencing was used to identify signalling pathways mainly affected. The amino acid-substituted diet shows remarkable preventive and therapeutic effects. This dietary approach corrects the whole-body glucose metabolism and restores the unbalanced metabolic substrate usage - by improving mitochondrial fuel oxidation - in the failing heart. In particular, biochemical, molecular, and genetic approaches suggest that renormalization of branched-chain amino acid oxidation in cardiac tissue, which is suppressed in HFrEF, plays a relevant role. Beyond the changes of systemic metabolism, cell-autonomous processes may explain at least in part the diet's cardioprotective impact. Conclusion: Collectively, these results suggest that manipulation of dietary amino acids, and especially essential amino acids, is a potential adjuvant therapeutic strategy to treat systolic dysfunction and HFrEF in humans

ATENÇÃO BÁSICA E PREVENÇÃO DO CÂNCER DE MAMA

Breast cancer is one of the main public health problems worldwide, affecting millions of women each year. Primary care plays a crucial role in the prevention, early detection and management of this disease. The objective of this study is to analyze the role of primary care in preventing breast cancer, highlighting its strategies for health promotion, education, screening and early interventions. The aim is to identify the best practices and scientific evidence that support the actions of primary care in reducing the incidence and mortality from breast cancer. To achieve our objective, we carried out an integrative literature review. The integrative review is a method that allows the synthesis of research of different types, such as experimental, observational studies and systematic reviews, with the aim of obtaining a comprehensive view of the topic. Scientific databases were consulted, such as PubMed, Scopus and Google Scholar, using keywords related to primary care and breast cancer. Based on the integrative review carried out, we can conclude that primary care plays a fundamental role in preventing breast cancer. Strategies such as health education programs, breastfeeding promotion, regular screening and early interventions have proven effective in reducing the incidence and mortality from this disease.O câncer de mama é um dos principais problemas de saúde pública em todo o mundo, afetando milhões de mulheres a cada ano. A atenção básica desempenha um papel crucial na prevenção, detecção precoce e manejo dessa doença. O objetivo deste estudo é analisar o papel da atenção básica na prevenção do câncer de mama, destacando suas estratégias de promoção da saúde, educação, rastreamento e intervenções precoces. Busca-se identificar as melhores práticas e evidências científicas que embasam a atuação da atenção básica na redução da incidência e mortalidade por câncer de mama. Para alcançar nosso objetivo, realizamos uma revisão integrativa da literatura. A revisão integrativa é um método que permite a síntese de pesquisas de diferentes tipos, como estudos experimentais, observacionais e revisões sistemáticas, com o intuito de obter uma visão abrangente sobre o tema. Foram consultadas bases de dados científicas, como PubMed, Scopus e Google Scholar, utilizando palavras-chave relacionadas à atenção básica e câncer de mama. Com base na revisão integrativa realizada, podemos concluir que a atenção básica desempenha um papel fundamental na prevenção do câncer de mama. Estratégias como programas de educação em saúde, promoção da amamentação, rastreamento regular e intervenções precoces têm se mostrado eficazes na redução da incidência e mortalidade por essa doença

Whole Genome Expression Profiling of Semitendinosus Tendons from Children with Diplegic and Tetraplegic Cerebral Palsy

Cerebral palsy (CP) is the most common movement disorder in children, with a prevalence ranging from 1.5 to 4 per 1000 live births. CP is caused by a non-progressive lesion of the developing brain, leading to progressive alterations of the musculoskeletal system, including spasticity, often leading to the development of fixed contractures, necessitating tendon lengthening surgery. Total RNA-sequencing analysis was performed on semitendinosus tendons from diplegic and tetraplegic CP patients subjected to tendon lengthening surgery compared to control patients undergoing anterior cruciate ligament reconstructive surgery. Tetraplegic CP patients showed increased expression of genes implicated in collagen synthesis and extracellular matrix (ECM) turnover, while only minor changes were observed in diplegic CP patients. In addition, tendons from tetraplegic CP patients showed an enrichment for upregulated genes involved in vesicle-mediated transport and downregulated genes involved in cytokine and apoptotic signaling. Overall, our results indicate increased ECM turnover with increased net synthesis of collagen in tetraplegic CP patients without activation of inflammatory and apoptotic pathways, similar to observations in athletes where ECM remodeling results in increased tendon stiffness and tensile strength. Nevertheless, the resulting increased tendon stiffness is an important issue in clinical practice, where surgery is often required to restore joint mobility

DNA hydroxymethylation controls cardiomyocyte gene expression in development and hypertrophy

Methylation at 5-cytosine (5-mC) is a fundamental epigenetic DNA modification associated recently with cardiac disease. In contrast, the role of 5-hydroxymethylcytosine (5-hmC)-5-mC's oxidation product-in cardiac biology and disease is unknown. Here we assess the hydroxymethylome in embryonic, neonatal, adult and hypertrophic mouse cardiomyocytes, showing that dynamic modulation of hydroxymethylated DNA is associated with specific transcriptional networks during heart development and failure. DNA hydroxymethylation marks the body of highly expressed genes as well as distal regulatory regions with enhanced activity. Moreover, pathological hypertrophy is characterized by a shift towards a neonatal 5-hmC distribution pattern. We also show that the ten-eleven translocation 2 (TET2) enzyme regulates the expression of key cardiac genes, such as Myh7, through 5-hmC deposition on the gene body and at enhancers. Thus, we provide a genome-wide analysis of 5-hmC in the cardiomyocyte and suggest a role for this epigenetic modification in heart development and disease

An autofluorescence-based method for the isolation of highly purified ventricular cardiomyocytes

Aims The aim of our study was to set up a simple and reliable isolation method of living ventricular cardiomyocytes (vCMs) for molecular and biological studies. Methods and results A standard technique for the retrograde perfusion of an enzymatic solution was used to isolate cardiac cells from adult mouse heart. Fluorescence-activated cell sorting (FACS) on adult murine cardiac ventricle cells was performed, comparing the intrinsic autofluorescence in the FITC channel and the forward scatter (FSC) parameter in order to isolate highly fluorescent cells. The expression of cell-specific mRNAs was assessed with real-time PCR in cells sorted on the basis of their FITC and FSC characteristics. We identified two distinct subpopulations of cells harvested after retrograde perfusion of wild-type heart: FITC high /FSC dim and FITC dim /FSC high. Immunophenotyping and mRNA analysis (qPCR and RNA sequencing) revealed that only FITC high /FSC dim cells were highly enriched in CM markers. Genes with high expression in endothelial cells and fibroblasts were enriched in the FITC dim /FSC high subpopulation. With the use of tdTomato fl/fl -α-myosin heavy chain MerCreMer +/' mouse heart, we found that tdTomato-positive vCMs were present in the FITC high /FSC dim region but were only rare in the FITC dim /FSC high fraction. Conclusion We have developed a simple and reliable method for the isolation of highly purified vCMs from the adult murine myocardium, avoiding fixation and permeabilization steps. These isolated vCMs can be used in particular for detailed molecular studies, avoiding contamination with other myocardial cell types

The epigenetic modifier DOT1L regulates gene regulatory networks necessary for cardiac patterning and cardiomyocyte cell cycle withdrawal

Mechanisms by which specific histone modifications regulate distinct gene regulatory networks remain little understood. We investigated how H3K79me2, a modification catalyzed by DOT1L and previously considered a general transcriptional activation mark, regulates gene expression in mammalian cardiogenesis. Early embryonic cardiomyocyte ablation of Dot1l revealed that H3K79me2 does not act as a general transcriptional activator, but rather regulates highly specific gene regulatory networks at two critical cardiogenic junctures: left ventricle patterning and postnatal cardiomyocyte cell cycle withdrawal. Mechanistic analyses revealed that H3K79me2 in two distinct domains, gene bodies and regulatory elements, synergized to promote expression of genes activated by DOT1L. Surprisingly, these analyses also revealed that H3K79me2 in specific regulatory elements contributed to silencing genes usually not expressed in cardiomyocytes. As DOT1L mutants had increased numbers of postnatal mononuclear cardiomyocytes and prolonged cardiomyocyte cell cycle activity, controlled inhibition of DOT1L might be a strategy to promote cardiac regeneration post-injury

DOT1L regulates chamber-specific transcriptional networks during cardiogenesis and mediates postnatal cell cycle withdrawal

Mechanisms by which specific histone modifications regulate distinct gene networks remain little understood. We investigated how H3K79me2, a modification catalyzed by DOT1L and previously considered a general transcriptional activation mark, regulates gene expression during cardiogenesis. Embryonic cardiomyocyte ablation of Dot1l revealed that H3K79me2 does not act as a general transcriptional activator, but rather regulates highly specific transcriptional networks at two critical cardiogenic junctures: embryonic cardiogenesis, where it was particularly important for left ventricle-specific genes, and postnatal cardiomyocyte cell cycle withdrawal, with Dot1L mutants having more mononuclear cardiomyocytes and prolonged cardiomyocyte cell cycle activity. Mechanistic analyses revealed that H3K79me2 in two distinct domains, gene bodies and regulatory elements, synergized to promote expression of genes activated by DOT1L. Surprisingly, H3K79me2 in specific regulatory elements also contributed to silencing genes usually not expressed in cardiomyocytes. These results reveal mechanisms by which DOT1L successively regulates left ventricle specification and cardiomyocyte cell cycle withdrawal