Hypertrophic Heart Disease Research Articles

The functional role of m6A demethylase ALKBH5 in cardiomyocyte hypertrophy

Cardiomyocyte hypertrophy is a major outcome of pathological cardiac hypertrophy. The m6A demethylase ALKBH5 is reported to be associated with cardiovascular diseases, whereas the functional role of ALKBH5 in cardiomyocyte hypertrophy remains confused. We engineered Alkbh5 siRNA (siAlkbh5) and Alkbh5 overexpressing plasmid (Alkbh5 OE) to transfect cardiomyocytes. Subsequently, RNA immunoprecipitation (RIP)-qPCR, MeRIP-qPCR analysis and the dual-luciferase reporter assays were applied to elucidate the regulatory mechanism of ALKBH5 on cardiomyocyte hypertrophy. Our study identified ALKBH5 as a new contributor of cardiomyocyte hypertrophy. ALKBH5 showed upregulation in both phenylephrine (PE)-induced cardiomyocyte hypertrophic responses in vitro and transverse aortic constriction (TAC)/high fat diet (HFD)-induced pathological cardiac hypertrophy in vivo. Knockdown or overexpression of ALKBH5 regulated the occurrence of hypertrophic responses, including the increased cardiomyocyte surface areas and elevation of the hypertrophic marker levels, such as brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP). Mechanically, we indicated that ALKBH5 activated JAK2/STAT3 signaling pathway and mediated m6A demethylation on Stat3 mRNA, but not Jak2 mRNA, resulting in the phosphorylation and nuclear translocation of STAT3, which enhances the transcription of hypertrophic genes (e.g., Nppa) and ultimately leads to the emergence of cardiomyocytes hypertrophic growth. Our work highlights the functional role of ALKBH5 in regulating the onset of cardiomyocyte hypertrophy and provides a potential target for hypertrophic heart diseases prevention and treatment.ALKBH5 activated JAK2/STAT3 signaling pathway and mediated m6A demethylation on Stat3 mRNA, but not Jak2 mRNA, resulting in the phosphorylation and nuclear translocation of STAT3, which enhances the transcription of hypertrophic genes (e.g., Nppa) and ultimately leads to the emergence of cardiomyocytes hypertrophic growth.

Endogenous adenine is a potential driver of the cardiovascular-kidney-metabolic syndrome.

Mechanisms underlying the cardiovascular-kidney-metabolic (CKM) syndrome are unknown, although key small molecule metabolites may be involved. Bulk and spatial metabolomics identified adenine to be upregulated and specifically enriched in coronary blood vessels in hearts from patients with diabetes and left ventricular hypertrophy. Single nucleus gene expression studies revealed that endothelial methylthioadenosine phosphorylase (MTAP) was increased in human hearts with hypertrophic cardiomyopathy. The urine adenine/creatinine ratio in patients was predictive of incident heart failure with preserved ejection fraction. Heart adenine and MTAP gene expression was increased in a 2-hit mouse model of hypertrophic heart disease and in a model of diastolic dysfunction with diabetes. Inhibition of MTAP blocked adenine accumulation in the heart, restored heart dysfunction in mice with type 2 diabetes and prevented ischemic heart damage in a rat model of myocardial infarction. Mechanistically, adenine-induced impaired mitophagy was reversed by reduction of mTOR. These studies indicate that endogenous adenine is in a causal pathway for heart failure and ischemic heart disease in the context of CKM syndrome.

The challenges in risk assessment of the military profession: A case of apical hypertrophic heart disease

The challenges in risk assessment of the military profession: A case of apical hypertrophic heart disease

Adequacy of Size Matching With Predicted Heart Mass Ratio in Diverse Types of Cardiomyopathies

Predicted heart mass ratio (PHMr) has been proposed as an optimal size metric in the selection of a donor heart for transplant; however, it is not known if the same size matching criteria pertains uniformly to all types of cardiomyopathies. Heart transplant recipients in the United Network for Organ Sharing registry database were categorized into 6 groups based on the type of cardiomyopathy, dilated, coronary artery disease, hypertrophic, restrictive, valvular and adult congenital heart disease. Patients in each group of etiology were stratified based on the PHMr into 5 groups: severely undersized <0.86, moderately undersized 0.86 to 0.94, matched 0.95 to 1.04, moderately oversized 1.05 to 1.24, and severely oversized >1.25. The survival and cause of death of patients in each etiology group were reviewed. The United Network for Organ Sharing registry database from January 1987 to July 2021 included 53,573 patients who received a heart transplant. Compared with patients with size matched hearts, recipients with dilated (hazard ratio 1.17, p=0.001) and valvular (hazard ratio 1.79, p=0.032) cardiomyopathy who had an undersized heart with PHMr <0.86 had decreased survival. In addition, the survival of patients with hypertrophic or restrictive cardiomyopathy and adult congenital heart disease was not affected by size matching based on the PHMr (0.601 and 0.079, respectively, p=0.873). In conclusion, our analysis suggests that the size matching criteria based on PHMr may not be uniform to all patients across various etiologies of cardiomyopathy. Therefore, the data can be used to increase the acceptance rate of donor hearts, particularly, for patients with hypertrophic, restrictive cardiomyopathy and congenital heart disease in which size matching is less significant for survival outcome.

P479 PATIENT WITH REGRESSION MULTIPLE MYELOMA AND INFILTRATIVE HYPERTROPHIC CARDIOMYOPATHY OF NDD UNDERGO CARDIAC TRANSPLANT

Abstract Introduction We report the case of a 52–year–old patient with a history of multiple myeloma undergoing chemotherapy treatment according to the DaraRD scheme and currently in remission. Associated with haematological pathology, infiltrative hypertrophic cardiomyopathy of ndd is highlighted. Following haematological and instrumental screening tests, the patient underwent a heart transplant for frequent exacerbations of heart failure. Case Report A 52–year–old patient, suffering from multiple myeloma for about 1 year, for which he began chemotherapy treatment with DaraRD scheme and good response to therapy. The patient also presented dyspnoic symptoms and declining edema with echocardiographic finding of infiltrative hypertrophic heart disease for which he undergoes diagnostic investigations. He performs: • Serial echocardiograms which showed marked uniform hypertrophy with ground glass appearance of the left ventricle and severely reduced systolic function; • PET–CT with no hyperaccumulation of the radiopharmaceutical; • Cardiac MRI with evidence of severely hypocontractile left ventricle and wall changes which could be associated with amyloid infiltration; • myocardial scintigraphy that does not give evidence for the deposit of the amyloid substance of the ATTR type in the heart; • biopsy of umbilical fat and cardiac biopsy, both negative for deposition of substance AL with Congo Red staining; • Right cardiac catheterization with evidence of post–capillary pulmonary hypertension. The patient was subjected to several exacerbations of heart failure which required continuous infusion therapy with inotropes and, ultimately, heart transplantation. At the time of surgery, the heart appeared enlarged, extremely hypocontractile and with rigid walls, with poor compliance of the ventricular muscle wall. The patient responded well to the surgical procedure, in the absence of signs and symptoms of rejection, with improvement of general clinical condition. Conclusions At the end of the surgical procedure and the rehabilitation period, the patient was discharged home, without showing signs and symptoms of graft rejection or multiple myeloma exacerbations, in stable and satisfactory general clinical conditions.

Molecular perspectives in hypertrophic heart disease: An epigenetic approach from chromatin modification.

Epigenetic changes induced by environmental factors are increasingly relevant in cardiovascular diseases. The most frequent molecular component in cardiac hypertrophy is the reactivation of fetal genes caused by various pathologies, including obesity, arterial hypertension, aortic valve stenosis, and congenital causes. Despite the multiple investigations performed to achieve information about the molecular components of this pathology, its influence on therapeutic strategies is relatively scarce. Recently, new information has been taken about the proteins that modify the expression of fetal genes reactivated in cardiac hypertrophy. These proteins modify the DNA covalently and induce changes in the structure of chromatin. The relationship between histones and DNA has a recognized control in the expression of genes conditioned by the environment and induces epigenetic variations. The epigenetic modifications that regulate pathological cardiac hypertrophy are performed through changes in genomic stability, chromatin architecture, and gene expression. Histone 3 trimethylation at lysine 4, 9, or 27 (H3-K4; -K9; -K27me3) and histone demethylation at lysine 9 and 79 (H3-K9; -K79) are mediators of reprogramming in pathologic hypertrophy. Within the chromatin architecture modifiers, histone demethylases are a group of proteins that have been shown to play an essential role in cardiac cell differentiation and may also be components in the development of cardiac hypertrophy. In the present work, we review the current knowledge about the influence of epigenetic modifications in the expression of genes involved in cardiac hypertrophy and its possible therapeutic approach.

NLRP3 Inflammasome Activation Through Heart-Brain Interaction Initiates Cardiac Inflammation and Hypertrophy During Pressure Overload.

Mechanical stress on the heart, such as high blood pressure, initiates inflammation and causes hypertrophic heart disease. However, the regulatory mechanism of inflammation and its role in the stressed heart remain unclear. IL-1β (interleukin-1β) is a proinflammatory cytokine that causes cardiac hypertrophy and heart failure. Here, we show that neural signals activate the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3) inflammasome for IL-1β production to induce adaptive hypertrophy in the stressed heart. C57BL/6 mice, knockout mouse strains for NLRP3 and P2RX7 (P2X purinoceptor 7), and adrenergic neuron-specific knockout mice for SLC17A9, a secretory vesicle protein responsible for the storage and release of ATP, were used for analysis. Pressure overload was induced by transverse aortic constriction. Various animal models were used, including pharmacological treatment with apyrase, lipopolysaccharide, 2'(3')-O-(4-benzoylbenzoyl)-ATP, MCC950, anti-IL-1β antibodies, clonidine, pseudoephedrine, isoproterenol, and bisoprolol, left stellate ganglionectomy, and ablation of cardiac afferent nerves with capsaicin. Cardiac function and morphology, gene expression, myocardial IL-1β and caspase-1 activity, and extracellular ATP level were assessed. In vitro experiments were performed using primary cardiomyocytes and fibroblasts from rat neonates and human microvascular endothelial cell line. Cell surface area and proliferation were assessed. Genetic disruption of NLRP3 resulted in significant loss of IL-1β production, cardiac hypertrophy, and contractile function during pressure overload. A bone marrow transplantation experiment revealed an essential role of NLRP3 in cardiac nonimmune cells in myocardial IL-1β production and cardiac phenotype. Pharmacological depletion of extracellular ATP or genetic disruption of the P2X7 receptor suppressed myocardial NLRP3 inflammasome activity during pressure overload, indicating an important role of ATP/P2X7 axis in cardiac inflammation and hypertrophy. Extracellular ATP induced hypertrophic changes of cardiac cells in an NLRP3- and IL-1β-dependent manner in vitro. Manipulation of the sympathetic nervous system suggested sympathetic efferent nerves as the main source of extracellular ATP. Depletion of ATP release from sympathetic efferent nerves, ablation of cardiac afferent nerves, or a lipophilic β-blocker reduced cardiac extracellular ATP level, and inhibited NLRP3 inflammasome activation, IL-1β production, and adaptive cardiac hypertrophy during pressure overload. Cardiac inflammation and hypertrophy are regulated by heart-brain interaction. Controlling neural signals might be important for the treatment of hypertensive heart disease.

P289 EYESHOT OF CARDIAC AMYLOIDOSIS CASES PRESENTED TO A CARDIOLOGY UO IN CENTRAL ITALY IN 2021

Abstract Introduction ATTR–related cardiac amyloidosis, caused by the accumulation of insoluble fibrillar proteins derived from transthyretin misfolding, is an often underdiagnosed pathology, especially when neurological involvement is absent or minor. Transthoracic echocardiography represents the first fundamental step in the diagnostic process. Abstract During the year 2021, a total of 9 patients with an echocardiographic feature of hypertrophic heart disease suggestive of infiltrative pathology were referred to our Cardiology unit. Of these patients, 89% were male (8 out of 9), aged between 60 and 88 years (average age of 72 years). The clinic presentation was heart failure in 5 cases (55% of the total), arrhythmic storm in 1 case, history of amyloid polyneuropathy in 1 case and it was an occasional finding in 2 patients who required a cardiological evaluation for other reasons. The 12–lead ECG documented atrial fibrillation arrhythmia in 4 out of 9 cases (44%) and sinus rhythm in the remaining 5 cases (56%). Transthoracic echocardiography revealed left ventricular hypertrophy with granular sparkling aspect of the SIV in all patients, with indexes of global systolic function preserved in 4 out of 9 cases (44%), moderately reduced in 3 out of 9 cases (33%) and severely reduced in the remaining 2 cases (22%). Diastolic dysfunction was present in all patients, with a restrictive pattern in 4 of 9 cases (44%). Myocardial scintigraphy with DPD was performed in 7 patients, which confirmed the suspicion of aTTR amyloidosis in 6 cases (Perugini Score = 2), in the remaining 2 patients the diagnostic procedure was not performed due to severe comorbidities. At present, diagnostic confirmation of aTTR amyloidosis has been confirmed by biopsy in 2 patients; a patient‘s biopsy is currently under analysis; 1 patient is on Patisiran therapy. Conclusions Cardiac amyloidosis represents a frequent clinical condition especially in the elderly population. In the light of the most recent therapeutic strategies, a correct and early etiopathogenetic diagnosis is of fundamental importance.

The Combination of Feature Tracking and Late Gadolinium Enhancement for Identification Between Hypertrophic Cardiomyopathy and Hypertensive Heart Disease.

BackgroundThe differentiation between hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) is challenging due to similar myocardial hypertrophic phenotype. The purpose of this study is to evaluate the feasibility of cardiovascular magnetic resonance feature tracking (CMR-FT) and late gadolinium enhancement (LGE) to distinguish between HCM and HHD and the potential relationship between myocardial strain and cardiac functional parameters.MethodsOne hundred and seventy subjects (57 HCM, 45 HHD, and 68 controls) underwent 3.0 T CMR, including steady-state free precession cines and LGE images. Global and segmental (basal, mid, and apical) analyses of myocardial radial, circumferential, longitudinal strain, and left ventricular (LV) torsion, as well as global and 16 segments of LGE were assessed. The multivariate analysis was used to predict the diagnostic ability by combining comprehensive myocardial strain parameters and LGE.ResultsGlobal radial strain (GRS), global circumferential strain (GCS), and LV torsion were significantly higher in the HCM group than in the HHD group (GRS, 21.18 ± 7.52 vs. 14.56 ± 7.46%; GCS, −13.34 ± 3.52 vs. −10.11 ± 4.13%; torsion, 1.79 ± 0.69 vs. 1.23 ± 0.65 deg/cm, all P < 0.001). A similar trend was also seen in the corresponding strain rate. As for segmental strain analysis, basal radial strain (BRS), basal circumferential strain (BCS), basal longitudinal strain (BLS), mid-radial strain (MRS), and mid-circumferential strain (MCS) were higher in the HCM group than in the HHD group (all P < 0.001). The receiver operating characteristic (ROC) results showed that the area under the curve (AUC) of LGE in the mid-interventricular septum (mIVS) was the highest among global and segmental LGE analyses. On the multivariate regression analysis, a combined model of LGE (mIVS) with GRS obtained the highest AUC value, which was 0.835 with 88.89% sensitivity and 70.18% specificity, respectively. In addition, for patients with HCM, GRS, GCS, and global longitudinal strain had correlations with LV ejection fraction (LVEF), maximum interventricular septum thickness (IVST max), and left ventricular mass index (LVMi). Torsion was mildly associated with LVEF.ConclusionCMR-FT-derived myocardial strain and torsion provided valuable methods for evaluation of HCM and HHD. In addition, the combination of GRS and LGE (mIVS) achieved the highest diagnostic value.

ATGL deficiency aggravates pressure overload-triggered myocardial hypertrophic remodeling associated with the proteasome-PTEN-mTOR-autophagy pathway.

Persistent myocardial hypertrophy frequently leads to heart failure (HF). Intramyocardial triacylglycerol (TAG) accumulation is closely related with cardiac remodeling and abnormal contractile function. Adipose triglyceride lipase (ATGL), a key enzyme in TAG metabolism, regulates cardiac function. However, its associated molecular pathways have not been fully defined. Here, cardiac hypertrophy and HF were induced in wild-type (WT) or ATGL knockout (KO) mice through transverse aortic constriction (TAC) for up to 4weeks. TAC in WT mice significantly reduced cardiac function and autophagy while enhancing left ventricular hypertrophy, interstitial fibrosis, inflammatory response, superoxide generation, and cardiomyocyte apoptosis, accompanied with upregulation of the proteasome activity, reduction of PTEN level and activation of AKT-mTOR signaling, and these effects were further aggravated in ATGL KO mice. Interestingly, ATGL KO-mediated cardiac dysfunction and remodeling were markedly reversed by proteasome inhibitor (epoxomicin) or autophagic activator (rapamycin), but accelerated by PTEN inhibitor (VO-OHpic) or autophagy inhibitor 3-MA. Mechanistically, ATGL KO upregulated proteasome expression and activity, which in turn mediates PTEN degradation leading to activation of AKT-mTOR signaling and inhibition of autophagy, thereby enhancing hypertrophic remodeling and HF. In conclusion, ATGL KO contributes to TAC-induced cardiac dysfunction and adverse remodeling probably associated with the proteasome-PTEN-mTOR-autophagy pathway. Therefore, modulation of this pathway may have a therapeutic effect potential for hypertrophic heart disease. TAC-induced downregulation of ATGL results in increased proteasome (β1i/β2i/β5i) activity, which in turn promotes degradation of PTEN and activation of AKT-mTOR signaling and then inhibits autophagy and ATP production, thereby leading to cardiac hypertrophic remodeling and dysfunction. Conversely, blocking proteasome activity or activating autophagy attenuates these effects.

AntimiR-132 Attenuates Myocardial Hypertrophy in an Animal Model of Percutaneous Aortic Constriction

BackgroundPathological cardiac hypertrophy is a result of afterload-increasing pathologies including untreated hypertension and aortic stenosis. It features progressive adverse cardiac remodeling, myocardial dysfunction, capillary rarefaction, and interstitial fibrosis often leading to heart failure. ObjectivesThis study aimed to establish a novel porcine model of pressure-overload–induced heart failure and to determine the effect of inhibition of microribonucleic acid 132 (miR-132) on heart failure development in this model. MethodsThis study developed a novel porcine model of percutaneous aortic constriction by implantation of a percutaneous reduction stent in the thoracic aorta, inducing progressive remodeling at day 56 (d56) after pressure-overload induction. In this study, an antisense oligonucleotide specifically inhibiting miR-132 (antimiR-132), was regionally applied via intracoronary injection at d0 (percutaneous transverse aortic constriction induction) and d28. ResultsAt d56, antimiR-132 treatment diminished cardiomyocyte cross-sectional area (188.9 ± 2.8 vs. 258.4 ± 9.0 μm2 in untreated hypertrophic hearts) and improved global cardiac function (ejection fraction 48.9 ± 1.0% vs. 36.1 ± 1.7% in control hearts). Moreover, at d56 antimiR-132-treated hearts displayed less increase of interstitial fibrosis compared with sham-operated hearts (Δsham 1.8 ± 0.5%) than control hearts (Δsham 10.8 ± 0.6%). Of note, cardiac platelet and endothelial cell adhesion molecule 1+ capillary density was higher in the antimiR-132–treated hearts (647 ± 20 cells/mm2) compared with in the control group (485 ± 23 cells/mm2). ConclusionsThe inhibition of miR-132 is a valid strategy in prevention of heart failure progression in hypertrophic heart disease and may be developed as a treatment for heart failure of nonischemic origin.

MRNA modifications in cardiovascular biology and disease: with a focus on m6A modification.

Among several known RNA modifications, N6-methyladenosine (m6A) is the most studied RNA epitranscriptomic modification and controls multiple cellular functions during development, differentiation, and disease. Current research advancements have made it possible to examine the regulatory mechanisms associated with RNA methylation and reveal its functional consequences in the pathobiology of many diseases, including heart failure. m6A methylation has been described both on coding (mRNA) and non-coding RNA species including rRNA, tRNA, small nuclear RNA and circular RNAs. The protein components which catalyze the m6A methylation are termed methyltransferase or 'm6A writers'. The family of proteins that recognize this methylation are termed 'm6A readers' and finally the enzymes involved in the removal of a methyl group from RNA are known as demethylases or 'm6A erasers'. At the cellular level, different components of methylation machinery are tightly regulated by many factors to maintain the m6A methylation dynamics. The m6A methylation process impacts different stages of mRNA metabolism and the biogenesis of long non-coding RNA and miRNA. Although, mRNA methylation was initially described in the 1970s, its regulatory roles in various diseases, including cardiovascular diseases are broadly unexplored. Recent investigations suggest the important role of m6A mRNA methylation in both hypertrophic and ischaemic heart diseases. In the present review, we evaluate the significance of m6A methylation in the cardiovascular system, in cardiac homeostasis and disease, all of which may help to improve therapeutic intervention for the treatment of heart failure. RNA methylation in cardiovascular diseases: altered m6A RNA (coding and non-coding RNA) methylation is identified during different cardiovascular diseases. Increased cardiac hypertrophy is observed following METTL3 overexpression. In contrast, reduced FTO level was seen in mice following myocardial infarction. Increased cardiac fibroblasts activation or increased atherosclerotic plaques were also co-related with m6A RNA methylation.

S‐acyltransferase zDHHC9 Promotes Pathogenic Signaling in the Heart

Heart disease remains a leading cause of mortality, contributing to over 600,000 deaths per year in the United States. Notwithstanding, the molecular mechanisms underlying the pathophysiology of heart disease remain largely elusive. Receptors, ion channels, and signaling proteins that regulate cardiac contractility and physiology are modified by post-translational modifications such as phosphorylation. Recent research into the roles of S-acylation or palmitoylation, the reversible post-translational modification of proteins with fatty acids, has demonstrated critical functions in the regulation of intracellular signaling in physiology and disease. Palmitoylation, which is catalyzed by the zinc finger Asp-His-His-Cys (zDHHC) family of S-acyltransferases, has been implicated in trafficking, stability, sorting and binding of proteins to cofactors. However, the roles of palmitoylation in cardiac signal transduction and cardiac pathogenesis are not well understood. Our preliminary work indicates that cardiac-specific transgenic overexpression of the Golgi-specific acyl transferase zDHHC9 (TgZdhhc9) results in cardiac hypertrophy and severe cardiomyopathy at six and eight months of age respectively in mice. Furthermore, using unbiased palmitoyl proteomics, we discovered that zDHHC9 palmitoylates Rab3 GTPase-activating protein catalytic subunit (Rab3gap1) that hydrolyzes the active GTP-bound form of Rab3 GTPase protein (Rab3) and inactivates Rab3 function. More so, mice subjected to transverse aortic constriction surgery, a pressure-overload model of pathological cardiac hypertrophy, showed increased palmitoylation of Rab3gap1, compared to sham controls. In addition, we observed that overexpression of zDHHC9 resulted in retention of Rab3gap1 at the Golgi and post-Golgi vesicles in cardiomyocytes and TgZdhhc9 hearts showed increased levels of Rab3a-GTP prior to disease onset, suggesting enhancement of cardiac Rab3a activity. Ongoing research will identify which hypertrophic signaling effectors are modulated by the zDHHC9/ Rab3gap1/Rab3a cascade in the heart. Altogether, these data suggest zDHHC9-mediated palmitoylation of Rab3gap1 may contribute to hypertrophic signaling and heart disease.

Hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) diagnosis using echocardiography and electrocardiography

ABSTRACT Echocardiography and electrocardiogram (ECG) are the primary tools used by cardiologists to diagnose cardiovascular heart diseases. Contrary to the critical role of combining the echocardiography and ECG information in clinical examinations, to our knowledge, no study has considered this to classify heart diseases. Left ventricular hypertrophy (LVH) is caused by a variety of origins such as hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD). Differentiating HCM and HHD is challenging . We proposed an HCM and HHD patient classifier to use ECG and echocardiography information. Longitudinal strain and strain rate from echocardiography frames and amplitude and temporal features from ECG signals, are extracted. To eliminate incompetent features, Fisher’s discrimination ratio (FDR), information gain, and Relief-F weights are used. Finally, support vector machine (SVM) and K-nearest neighbours classifiers are used to classify the normal, HCM, and HHD subjects. The results on 30 subjects show that the best classification refers to SVM classifier using five selected features from ECG and echocardiography information using FDR. The precision, sensitivity, and F-measure are 97.62, 93.33 and 95.43%, respectively. According to the results, the combination of echocardiography and ECG information leads to diagnosis improvement compared to the classification based on separated information of ECG and echocardiography.

VEGF-C/VEGFR-3 axis protects against pressure-overload induced cardiac dysfunction through regulation of lymphangiogenesis.

Prolonged pressure overload triggers cardiac hypertrophy and frequently leads to heart failure (HF). Vascular endothelial growth factor‐C (VEGF‐C) and its receptor VEGFR‐3 are components of the central pathway for lymphatic vessel growth (also known as lymphangiogenesis), which has crucial functions in the maintenance of tissue fluid balance and myocardial function after ischemic injury. However, the roles of this pathway in the development of cardiac hypertrophy and dysfunction during pressure overload remain largely unknown. Eight‐ to 10‐week‐old male wild‐type (WT) mice, VEGFR‐3 knockdown (VEGFR‐3f/−) mice, and their WT littermates (VEGFR‐3f/f) were subjected to pressure overload induced by transverse aortic constriction (TAC) for 1–6 weeks. We found that cardiac lymphangiogenesis and the protein expression of VEGF‐C and VEGFR‐3 were upregulated in the early stage of cardiac hypertrophy but were markedly reduced in failing hearts. Moreover, TAC for 6 weeks significantly reduced cardiac lymphangiogenesis by inhibiting activation of VEGFR‐3‐mediated signals (AKT/ERK1/2, calcineurin A/NFATc1/FOXc2, and CX43), leading to increased cardiac edema, hypertrophy, fibrosis, apoptosis, inflammation, and dysfunction. These effects were further aggravated in VEGFR‐3f/− mice and were dose‐dependently attenuated by delivery of recombinant VEGF‐C156S in WT mice. VEGF‐C156s administration also reversed pre‐established cardiac dysfunction induced by sustained pressure overload. Thus, these results demonstrate, for the first time, that activation of the VEGF‐C‐VEGFR‐3 axis exerts a protective effect during the transition from cardiac hypertrophy to HF and highlight selective stimulation of cardiac lymphangiogenesis as a potential new therapeutic approach for hypertrophic heart diseases.

SOCS3 Negatively Regulates Cardiac Hypertrophy via Targeting GRP78-Mediated ER Stress During Pressure Overload.

Pressure overload-induced hypertrophic remodeling is a critical pathological process leading to heart failure (HF). Suppressor of cytokine signaling-3 (SOCS3) has been demonstrated to protect against cardiac hypertrophy and dysfunction, but its mechanisms are largely unknown. Using primary cardiomyocytes and cardiac-specific SOCS3 knockout (SOCS3cko) or overexpression mice, we demonstrated that modulation of SOCS3 level influenced cardiomyocyte hypertrophy, apoptosis and cardiac dysfunction induced by hypertrophic stimuli. We found that glucose regulatory protein 78 (GRP78) was a direct target of SOCS3, and that overexpression of SOCS3 inhibited cardiomyocyte hypertrophy and apoptosis through promoting proteasomal degradation of GRP78, thereby inhibiting activation of endoplasmic reticulum (ER) stress and mitophagy in the heart. Thus, our results uncover SOCS3-GRP78-mediated ER stress as a novel mechanism in the transition from cardiac hypertrophy to HF induced by sustained pressure overload, and suggest that modulating this pathway may provide a new therapeutic approach for hypertrophic heart diseases.

CRD-733, a Novel PDE9 (Phosphodiesterase 9) Inhibitor, Reverses Pressure Overload-Induced Heart Failure.

Augmentation of NP (natriuretic peptide) receptor and cyclic guanosine monophosphate (cGMP) signaling has emerged as a therapeutic strategy in heart failure (HF). cGMP-specific PDE9 (phosphodiesterase 9) inhibition increases cGMP signaling and attenuates stress-induced hypertrophic heart disease in preclinical studies. A novel cGMP-specific PDE9 inhibitor, CRD-733, is currently being advanced in human clinical studies. Here, we explore the effects of chronic PDE9 inhibition with CRD-733 in the mouse transverse aortic constriction pressure overload HF model. Adult male C57BL/6J mice were subjected to transverse aortic constriction and developed significant left ventricular (LV) hypertrophy after 7 days (P<0.001). Mice then received daily treatment with CRD-733 (600 mg/kg per day; n=10) or vehicle (n=17), alongside sham-operated controls (n=10). CRD-733 treatment reversed existing LV hypertrophy compared with vehicle (P<0.001), significantly improved LV ejection fraction (P=0.009), and attenuated left atrial dilation (P<0.001), as assessed by serial echocardiography. CRD-733 prevented elevations in LV end diastolic pressures (P=0.037) compared with vehicle, while lung weights, a surrogate for pulmonary edema, were reduced to sham levels. Chronic CRD-733 treatment increased plasma cGMP levels compared with vehicle (P<0.001), alongside increased phosphorylation of Ser273 of cardiac myosin binding protein-C, a cGMP-dependent protein kinase I phosphorylation site. The PDE9 inhibitor, CRD-733, improves key hallmarks of HF including LV hypertrophy, LV dysfunction, left atrial dilation, and pulmonary edema after pressure overload in the mouse transverse aortic constriction HF model. Additionally, elevated plasma cGMP may be used as a biomarker of target engagement. These findings support future investigation into the therapeutic potential of CRD-733 in human HF.

Zebrafish Heart as a Model to Elucidate the Mechanisms of Sudden Cardiac Death

The heart of zebrafish has been used as a simple, low-cost model to study development, structure and function of the heart from early to late stages of life. Also, it has been established as a model to study different cardiac pathologies generated through different methods. Cardiac pathologies include from functional disorders such as arrhythmia, to structural disorders such as hypertrophic heart disease; in many of them, genetic and molecular aspects have been associated. Noteworthy, some of these genetic and molecular factors have been invoked as causes of sudden cardiac death in humans. This adverse outcome is common in many cardiovascular pathologies and can occur at any age. Unfortunately, etiology and physiopathology of sudden cardiac death are unclear, so extensive research in this area is required. This mini-review highlight three related points: First, the relevance of sudden cardiac death in humans. Second, advances in knowledge of the development, function and pathologies in the zebrafish heart model. Finally, the possibility of using the zebrafish model for the study of sudden cardiac. For this review, a literature search was performed using the PubMed database and the search engine Google Scholar: the words sudden cardiac death, zebrafish, arrhythmias, cardiomyopathies were combined for this search.

Left ventricular septal convexity in differentiating hypertrophic cardiomyopathy from hypertensive heart disease – cardiac MRI study

Abstract Background Subjects with hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) have left ventricular hypertrophy (LVH). It is a common clinical problem to distinguish HCM from HHD. Septal convexity (SC) into the left ventricle is increased in subjects with hypertrophic cardiomyopathy (HCM)-causing mutations with and without LVH. Purpose Our objective was to study if SC by cardiac magnetic resonance (CMR) differentiates between HCM and HHD. Methods We measured SC in 29 subjects with hypertension and LVH (left ventricular maximal wall thickness (LVMWT) ≥13 mm), in 49 subjects with HCM (LVMWT ≥13 mm) caused by the D175N mutation in the alpha-tropomyosin (TPM1) or the Q1061X mutation in the myosin binding protein C (MYBPC3) genes, and in 20 healthy controls with no LVH. SC into the LV was measured in end-diastolic 4-chamber images as the maximal distance between LV septal endocardial border and a line connecting septal mid-wall points at the level of tricuspid valve insertion and at the level of apical right ventricular insertion on the LV. Results Subjects with HCM had significantly increased septal convexity compared to subjects with HHD both in non-indexed and in BSA-indexed measurements (10.7±4.0 mm vs 4.9±2.7 mm, P&amp;lt;0.001 and 5.5±2.1 mm/m2 vs 2.4±1.3 mm/m2, P&amp;lt;0.001). To differentiate between HCM and HHD, septal convexity cutoff value of 7.85 mm performed best with sensitivity of 77% and specificity of 90%. BSA-indexed SC cutoff value of 3.68 mm differentiated between HCM and HHD with sensitivity of 81% and specificity of 86%. Conclusions CMR derived septal convexity is easily measured and is useful in discriminating between HCM caused by sarcomere mutations versus HHD. Measurement of septal convexity Funding Acknowledgement Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Finnish Foundation of Cardiovascular Research, the special governmental subsidy for health sciences research of the University Hospital of Kuopio

PKG oxidation at Cys42 amplifies mTORC1 activation to worsen hypertrophic heart disease

Abstract Rationale Protein kinase G-1a (PKG1a) phosphorylation of tuberous sclerosis complex 2 (TSC2, or tuberin) at serine 1365 (S1365) potently suppresses mTORC1 activation. This results in greater autophagy and limits pathological hypertrophy myocytes and the heart. Cardiac stress also induce oxidation of PKG1a between cysteine 42 residues in homo-monomers, which reduces cardioprotection. Objective We tested the hypothesis that pathological mTORC1 activation is potently amplified by concomitant PKG1a C42-oxidation, and that this is countered by stimulating soluble guanylyl cyclase-1 (GC-1). Methods and results In mice expressing only C42-redox inhibited PKG1a (PKG1aCS), pressure-overload (PO) induces markedly less mTORC1 activation, increasing autophagic flux and reducing protein aggregation, hypertrophy, and dysfunction compared to PO in PKG1aWT mice. Similar results were obtained in cardiomyocytes exposed to endothelin-1. Protection against PO in PKG1aCS mice was similar to PKG1aWT co-treated with the mTORC1-inhibitor everolimus. TSC2 S1365 phosphorylation increased more in PKG1aCS than PKG1aWT myocardium after PO. Knock-in mice with TSC2 S1365A and PKG1aCS mutations, to prevent TSC2 phosphorylation by PKG1a displayed amplified mTORC1, cardiodepression, and mortality after PO as compared to PKG1aCS. Lastly, the marked disparity between PKG1aWT and PKG1aCS PO phenotype for TSC2 S1365 phosphorylation, mTORC1 activation, and cardiac dysfunction is overcome by BAY-602770, a direct stimulator of GC-1. Conclusion Oxidant-induced PKG1a C42 dimerization blunts its attenuation of mTORC1 activity by reducing TSC2 S1365 phosphorylation, thereby contributing to inadequate autophagy and worsened hypertrophic dysfunction. This is ameliorated by direct GC-1 stimulation. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): DFG