Ventricular Hypertrophy Research Articles

Semaglutide normalizes increased cardiomyocyte calcium transients in a rat model of high fat diet-induced obesity.

Obesity increases the risk of heart failure with preserved (HFpEF), but not reduced ejection fraction (HFrEF). The glucagon-like peptide-1 receptor agonist (GLP-1-RA) semaglutide improves outcome of patients with obesity with or without HFpEF, while GLP-1-RAs were associated with adverse outcome in patients with HFrEF. Here, we investigate the effect of in vivo treatment with semaglutide on excitation-contraction coupling in a rat model of obesity. Rats received high-fat/high-fructose diet for 8weeks and were then randomized to semaglutide (HFD/Sema) or vehicle (HFD/Veh) for another 8weeks, during which they could choose between HFD and a low-fat/high-fructose diet (LFD). Control rats received either standard chow (CON), HFD or LFD only, without treatment. After 16weeks, sarcomere shortening and cytosolic Ca2+ concentrations ([Ca2+]c) were determined in isolated cardiomyocytes. Compared with CON, HFD/Veh increased the amplitude of [Ca2+]c transients and systolic sarcomere shortening in absence or presence of β-adrenergic stimulation, which was reversed by HFD/Sema. Caffeine-induced sarcoplasmic reticulum (SR) Ca2+ release and L-type Ca2+ channel (LTCC) currents were reduced by HFD/Sema versus HFD/Veh, while SR Ca2+ ATPase activity remained unaffected. Compared with HFD, LFD increased [Ca2+]c transients and sarcomere shortening further despite similar effects on body weight. While HFD increased cardiomyocyte [Ca2+]c transients and systolic sarcomere shortening, semaglutide normalized these alterations, mediated by reduced SR Ca2+ load and LTCC currents. Because increased LTCC currents were previously traced to cardiac hypertrophy, these effects may explain why GLP-1-RAs provide benefits for patients with obesity with or without HFpEF, but rather adverse outcome in HFrEF.

Left atrial function in uraemic patients: Four-dimensional automatic left atrial quantitative technology study.

This study aimed to evaluate the utility of left atrial volume and function in uraemic patients using four-dimensional automatic left atrial quantification (4D auto LAQ) technology. Thirty-four undialysed uraemic patients (U-ND group), 60 dialysed uraemic patients (U-D group), and 32 healthy volunteers (N group) were enrolled in our current study. Conventional echocardiographic parameters were recorded, and left atrial volume and strain parameters were analysed to determine statistical differences among the three groups. The Pearson correlation coefficient was employed to assess the relationships between left atrial ejection fraction and left atrial strain parameters. Compared to the N group, uraemic patients often displayed left atrial enlargement and left ventricular hypertrophy. Significant increases were noted in left atrial diameter, interventricular septum thickness, left ventricular posterior wall thickness, E/e', diastolic blood pressure, systolic blood pressure, left atrial minimum volume, left atrial maximum volume, left atrial pre-atrial contraction volume, left atrial emptying volume and left atrial maximum volume index (P<0.05). Conversely, the e', E/A ratio and left atrial reservoir longitudinal strain were significantly decreased (P<0.05). However, no statistically significant differences were observed in the aforementioned parameters between the U-ND and U-D groups. The absolute values of left atrial conduit longitudinal strain and left atrial conduit circumferential strain, as well as left atrial passive ejection fraction, were notably lower in the U-D group compared to the N and U-ND groups, with statistically significant differences identified among the three groups (P<0.05). Uraemic patients exhibit marked left atrial enlargement and left ventricular hypertrophy, coupled with altered atrial function, particularly ductal dysfunction in the U-D group. The 4D auto LAQ technology proves advantageous in detecting these alterations, offering a promising tool for thorough cardiac assessment in this patient cohort.

Significant regression of left ventricular hypertrophy in patient with arterial hypertension during antihypertensive treatment with perindopril and atorvastatin

Left ventricular hypertrophy (LVH) in arterial hypertension (AH) is one of the modifiable risk factors for cardiovascular events and serves as a justified goal for antihypertensive therapy. The article presents follow-up of a 60-year-old female with AH, hyperlipidemia, and discovered of LVH on the data of electrocardiography and echocardiography. In addition to the SokolowLyon and Cornell voltage criteria, the baseline echocardiographic examination revealed and increase in thickness of the ventricular septum and the left ventricular (LV) posterior wall, an increase in LV myocardial mass and LV myocardial mass index. The patient was recommended to take a drug of the class of angiotensin converting enzyme inhibitors perindopril and atorvastatin. The patient regularly received therapy and periodically underwent repeated echocardiographic examinations. After 40 months follow-up there are a significant decrease in septal hypertrophy (from 1.22 to 0.76 cm, -37.7%), LV posterior wall (from 1.05 to 0.49, -53.3%), as well as LV myocardial mass (from 197.9 to 96 g, -51.5%) and LV myocardial mass index (from 111.18 to 59.11 g/ m2, -51.5%). Thus, during the entire period of follow-up, the LV mass decreased almost twice. There was a decrease in the size of the left atrium, the relative wall thickness, with the same parameters of LV volumes, characteristics of systolic and diastolic function. Among the favorable factors contributing to significant LVH regression, high adherence to treatment, the efficacy of angiotensin converting enzyme inhibitors and the possible antihypertrophic influence of atorvastatin are discussed.

Epigenetic Study of Cohort of Monozygotic Twins With Hypertrophic Cardiomyopathy Due to MYBPC3 (Cardiac Myosin-Binding Protein C).

Hypertrophic cardiomyopathy is an autosomal dominant cardiac disease. The mechanisms that determine its variable expressivity are poorly understood. Epigenetics could play a crucial role in bridging the gap between genotype and phenotype by orchestrating the interplay between the environment and the genome regulation. In this study we aimed to establish a possible correlation between the peripheral blood DNA methylation patterns and left ventricular hypertrophy severity in patients with hypertrophic cardiomyopathy, evaluating the potential impact of lifestyle variables and providing a biological context to the observed changes. Methylation data were obtained from peripheral blood samples (Infinium MethylationEPIC BeadChip arrays). We employed multiple pair-matched models to extract genomic positions whose methylation correlates with the degree of left ventricular hypertrophy in 3 monozygotic twin pairs carrying the same founder pathogenic variant (MYBPC3 p.Gly263Ter). This model enables the isolation of the environmental influence, beyond age, on DNA methylation changes by removing the genetic background. Our results revealed a more anxious personality among more severely affected individuals. We identified 56 differentially methylated positions that exhibited moderate, proportional changes in methylation associated with left ventricular hypertrophy. These differentially methylated positions were enriched in regions regulated by repressor histone marks and tended to cluster at genes involved in left ventricular hypertrophy development, such as HOXA5, TRPC3, UCN3, or PLSCR2, suggesting that changes in peripheral blood may reflect myocardial alterations. We present a unique pair-matched model, based on 3 monozygotic twin pairs carrying the same founder pathogenic variant and different phenotypes. This study provides further evidence of the pivotal role of epigenetics in hypertrophic cardiomyopathy variable expressivity.

Activation patterns of intracellular signaling pathways in cardiac hypertrophy induced by different exercise modes in rats

Abstract Introduction Cardiac remodeling and hypertrophy cause as adaptive responses to physiological and pathological stimuli. Physiological cardiac hypertrophy is characterized by normal or enhanced cardiac function and myocardial metabolism, and induces concentric and eccentric hypertrophy by different exercise modes, without cardiac dysfunction and fibrosis. Each formative mechanism of cardiac hypertrophy is regulated by distinct and/or similar cellular signaling pathways. Activation of cardiac intracellular signaling pathway of phosphoinositide 3- kinase (PI3K) is involved in an underlying mechanism of developed eccentric cardiac hypertrophy by aerobic exercise training (AT). However, the activation patterns of intracellular signaling pathways of physiological cardiac hypertrophy by different exercise modes remain unclear. Purpose The purpose of this study was to investigate the activation patterns of intracellular signaling pathways in cardiac hypertrophy induced by different exercise modes, including AT, resistance training (RT), and high intensity interval training (HIIT). Methods Forty male 10-week-old Sprague-Dawley (SD) rats were divided into four groups; sedentary control (Con, n=10), AT (treadmill running, 60 min at 30 m/min, 5 days/wk for 8 wk, n=10), RT (ladder climbing, 8-10 sets/day, 3 d/wk for 8 wk, n=10), HIIT (14 repeats of 20-s swimming session with 10-s pause between sessions, 4 d/wk for 6 wk from 12-wk-old, n=10) groups. As a cardiac hypertrophic intracellular signaling pathways, PI3K protein expression level and mTOR and MAPK (ERK1/2, JNK1/2 and p38) phosphorylation levels in rat hearts were measured by Western blotting analysis. Results The hearts of rats in each training group developed cardiac hypertrophy. Moreover, the enzyme activity of oxidative phosphorylation in the skeletal muscle was promoted in the AT group, the oxidative phosphorylation and glycolytic enzyme activities were promoted in the HIIT group, and muscle hypertrophy occurred in the RT group. Levels of PI3K protein expression and mTOR phosphorylation in the heart were significantly higher in the AT, RT, and HIIT groups as compared to the Con group (each p&amp;lt;0.05). Additionally, p38 phosphorylation level in the heart was significantly higher in the RT group as compared to the Con, AT, and HIIT groups (each p&amp;lt;0.05). Furthermore, p44 ERK phosphorylation level in the heart of the RT group was significantly higher than that in the AT and HIIT groups (each p&amp;lt;0.05), but p42 ERK phosphorylation level did not differ among four groups. JNK1/2 (p46/p54) phosphorylation level in the heart was significantly higher in the RT group as compared to the Con group (p&amp;lt;0.05). Conclusion These findings suggest that the activation of PI3K-mTOR signaling pathway in the heart may be involved in the development of AT, RT and HIIT-induced cardiac hypertrophy, and the MAPK signaling activation may affect the development of cardiac hypertrophy by RT.

HECT domain containing-3 (HECTD3) E3 ubiquitin ligase attenuates cardiac ischemia and hypertrophy in mice

Abstract HECT domain containing 3 (HECTD3) is one of the E3 ubiquitin ligases, the cardiac function of which is not completely understood yet. We aimed here to understand the role of HECTD3 in cardiomyocytes using loss- and gain-of-function approaches in in vitro and in vivo models. Interestingly, we found that HECTD3 was significantly downregulated in cardiac tissue obtained from human patients suffering from cardiac hypertrophy and ischemia. We thus employed loss- and gain-of-function approaches in neonatal rat cardiomyocytes (NRVCMs) to get further insights into potential cardiac function of HECTD3. Overexpression of HECTD3 in NRVCMs attenuated cardiomyocyte hypertrophy and lipopolysaccharide (LPS) or interferon-γ (IFN- γ) induced cellular inflammation; its knockdown on the other hand aggravated these effects. Mechanistically, using Yeast two-hybrid screen, mass-spectrometry, and transcriptomics analyses, we identified Small Ubiquitin like Modifier 2 (SUMO2) Signal Transducer and Activator of Transcription-1 (STAT1) as novel substrates for HECTD3, regulation of which resulted into attenuation of hypertrophy and inflammation, respectively. To translate these in vitro results in vivo, we employed Adeno-associated virus-9 (AAV-9) mediated gene therapy approach to overexpress HECTD3 specifically in the heart of mouse models of cardiac ischemia due to permanent ligation of the left anterior descending artery (LAD), and cardiac hypertrophy due to transverse aortic constriction (TAC). Overexpression of HECTD3 in mice, though moderate but significantly improved cardiac function upon ischemic or hypertrophic stress compared to respective control groups. Importantly, in vitro findings were consistent in vivo, where AAV-9 mediated overexpression of HECTD3 substantially reduced cardiac hypertrophy and fibrosis, improved cardiac function as assessed by echocardiography, inhibited activation of STAT1-mediated downstream signaling, and attenuated infiltration of inflammatory cells to the heart after TAC or LAD ligation. This data indicates that HECTD3 is a novel modulator of cardiac ischemia, hypertrophy, and inflammation via regulation of SUMO2 and STAT1-signaling. In conclusion, we report here a novel cardioprotective mechanism involving the E3 ubiquitin ligase HECTD3, which exerts anti-hypertrophic and anti-inflammatory effects via dual regulation of SUMO2 and its SUMOylating target STAT1. We believe that this "dual pathway" inhibition exhibits translational importance and could further be exploited for the prevention and/or therapy of heart failure due to cardiac ischemia or hypertrophy.

Pathobiological characterization of pulmonary hypertension associated with heart failure with preserved ejection fraction

Abstract Introduction Heart failure with preserved ejection fraction (HFpEF) is an age-related cardiometabolic disease associated with vascular inflammation in cardiac tissue, pulmonary congestion and right ventricular dysfunction. Patients with HFpEF often develop pulmonary hypertension (PH) and right ventricular (RV) hypertrophy. Pulmonary vascular remodeling contributes to combined post- and precapillary PH (CpcPH), which is associated with worse outcome in humans. A recently developed meta-inflammatory murine HFpEF model approximates the characteristics of human HFpEF. Herein, HFpEF is induced by metabolic (high-fat diet (HFD)) and hypertensive stress (inhibition of constitutive NO synthase by Nω-nitro-1-arginomethyl ester (L-NAME)) over a 12-week period of time. With a focus on PH, we have developed a 'three-hit' model based on this model with a supplementary 21- or 42-day hypoxia phase (HFpEF-CpcPH). Methods Adult C57BL/6N mice were fed HFD for 15 or 18 weeks and supplied with L-NAME (0,5g/L or 1g/L) via drinking water, including a final period of 21 or 42 days, respectively, of hypoxia (normobaric, 10 % oxygen) or normoxia. Transthoracic echocardiography was performed using a small animal ultrasound device (Vevo 3100, Visual Sonics) and measurement of right ventricular systolic pressure (RVSP) using a Millar® pressure catheter (Mil-SPR-1000) inserted into the right ventricle. Right ventricular hypertrophy was measured as the ratio of the wet weight of the right ventricle to the left ventricle including the septum (RV/LV+S). Results Administration of HFD and L-NAME had no significant effect on RVSP in either HFpEF-normoxia group (15 weeks (n=8) or 18 weeks (n=5)) compared to the control group (n=8, n=5). 21 days of hypoxia increased RV systolic pressure (RVSP) to 37.05±1.6 (PH, n=8) and 40.33±0.87 mmHg (HFpEF-CpcPH, n=8) respectively, while 42 days of hypoxia caused no further increase (35.1±3.5 mmHg (PH, n=5) and 35.24±3.47 mmgHg (HFpEF-CpcPH, n=4)), respectively. RV hypertrophy (RV/LV+S) was significantly increased after 21 days of hypoxia in HFpEF-CpcPH compared to HFpEF (n=8) (34.42±1.75 vs. 24.93±1.1). Again, 42 days of hypoxia did not lead to a further increase in RV hypertrophy (35.2±3.9 vs. 25.80±4.39) in HFpEF-CpcPH, even though there was a significant difference compared to the HFpEF group. As expected, the heart weight/body weight ratio was significantly increased in HFpEF-CpcPH compared to HFpEF at both time points. However, mice under the prolonged hypoxia phase showed a significantly greater decrease in body weight, which complicates the interpretation of the results. Conclusion In summary, we could show that in the meta-inflammatory HFpEF model no significant PH can be observed within the investigated periods of time. However, a 21 day hypoxia phase was sufficient to induce a HFpEF-CpcPH phenotype. This model provides an important basis to develop new therapeutic approaches.

Cardiac secreted-HSP90alpha in cardiomyocyte hypertrophy by N-Cadherin mediated signaling under pressure overload

Abstract Background Left ventricular hypertrophy (LVH) in response to pressure overload is strongly associated with adverse cardiovascular outcomes. Heat shock protein 90 (HSP90) has been reported to be involved in cardiac remodeling under stress. Aims Here, we evaluate whether serum HSP90α (an isoform of HSP90) increases and associates with cardiac hypertrophy in patients with hypertension or severe aortic stenosis (AS), and explore the potential mechanisms in experimental pressure overload mouse model. Methods Serum HSP90α levels in patients with hypertension or aortic stenosis (AS) were determined by ELISA. Pressure overload mouse model was built by a transverse aortic constriction (TAC). Cardiac function was assessed by echocardiography. Cardiac hypertrophy was examined by histology, western blot and RNA analysis. Results Serum levels of HSP90α were higher in patients with hypertension or AS than in the control group, respectively, and the levels positively correlated with LVH. HSP90α levels also increased in heart tissues of patients with obstructive hypertrophic cardiomyopathy (HCM), and mice after TAC, in parallel with the hypertrophic markers. TAC induced the enhanced expression and secretion of HSP90α from cardiomyocytes and cardiac fibroblasts. Knockdown of HSP90α or blockade of extracellular HSP90α (eHSP90α) prevent the development of LVH under pressure overload in vivo and in vitro. By Nano-HPLC-MS/MS analysis, we identified eHSP90α interacted with N-cadherin in cardiomyocyte surface, which induced the activation of β-catenin and promoted β-catenin to bind TCF7 (a member of TCF/Lef family) in nucleus, enhanced the transcription of hypertrophic genes, contributing to cardiac hypertrophy and dysfunction under pressure overload. Conclusions Our data demonstrated that cardiac secreted-HSP90α promoted myocardial hypertrophy by N-Cadherin mediated β-catenin/TCF7 signaling under pressure overload. It indicates the therapeutic potential of targeting HSP90α-initiated signaling against cardiac hypertrophy and dysfunction under pressure overload.

Impact of cardiovascular risk factors in cardiac (reverse) remodelling induced by pregnancy

Abstract Introduction Haemodynamic overload during pregnancy induces cardiac remodelling, characterised by cardiac hypertrophy and chamber enlargement, associated with deterioration of diastolic function, despite preservation of the systolic function. After delivery, the woman's heart undergoes reverse remodelling(RR), and myocardial function and structure normalise to their pre-gravid state. The impact of cardiovascular risk factors(CRF) in cardiac remodelling and RR, namely, on cardiac function and structure, is variable and remains to be clarified. Purpose To characterise cardiac remodelling and RR during pregnancy and postpartum, respectively, and to investigate CRF's impact in these processes. Methods This prospective cohort study included volunteer pregnant women (healthy [H group] or obese and/or hypertensive and/or with gestational diabetes [CRF group]) recruited in two tertiary centres between 2019 and 2022. Women were evaluated by transthoracic echocardiography at the 1st trimester [1T,10-15 weeks, baseline], 3rd trimester [3T,30-35 weeks, peak of cardiac remodelling] of pregnancy as well as at the 1st, 6th and 12th month after delivery (during RR). Blood samples were collected in each evaluation moment to quantify plasma troponin I (cTnI), procollagen I COOH-terminal propeptide (PICP), ST2/IL33-receptor, C-reactive protein (CRP) and relaxin-2 by ELISA. Generalised linear mixed-effects models were used to evaluate the extent of RR and its potential predictors. Results We included 130 pregnant women with a median age of 33 [30,36] years, 41.5% with at least one CRF. As shown in Table 1, pregnant women developed cardiac hypertrophy with significant atrial and ventricular enlargement from 1T to 3T in both groups. A significant rise in filling pressures was also documented. During postpartum, a significant regression of cardiac hypertrophy and dilation was verified in the two study groups, accompanied by a significant decrease of E/e’ as soon as 1 month after delivery. These cardiac anatomical and functional adaptations induced by pregnancy were accompanied by a significant reduction in plasma cTnI, PICP, ST2/IL33-receptor, CRP and relaxin-2 levels from 3T to 6-months after delivery. Compared to the healthy pregnant women, the CRF group showed higher relative wall thickness (RWT) for all time points of the follow-up period, with similar values of indexed cardiac mass and volumes. Pregnant women with CRF revealed higher E/e’, contrasting with lower ejection fraction and worse global longitudinal strain. Conclusion The significant cardiac reverse remodelling occurred as soon as 1 month after delivery, returning to basal values 6 months postpartum, supported by a significant reduction of levels of plasma biomarkers related to myocardial injury, repair, fibrosis, and inflammation. Pregnant women with CRF showed higher RWT, impaired relaxation and subclinical LV dysfunction when compared with healthy women at all time points of the study.

Angiotensin II as a linking factor in cardiovascular disease enhanced cancer growth

Abstract Introduction Several publications have demonstrated that cardiovascular diseases (CVD) promote tumor growth in mouse models of breast, lung, and colon cancer, suggesting a causal relationship between both diseases. Cancer and CVD share several risk factors and pathophysiological mechanisms, including inflammation, oxidative stress, neurohormonal activation, and immune system dysfunction that combined could explain why patients with CVD are prone to develop cancer. Recent reports also suggest a link between hypertension and lung cancer, and between cardiac hypertrophy and breast cancer. Angiotensin II (ANGII) is a hormone involved in blood pressure regulation, vascular hemostasis and hypertrophy development. Moreover, ANGII is cancerogenic by increasing proliferation of several cancer cell types. Hence, ANGII could be a link in CVD-induced enhancement of cancer growth. Here, we investigated whether ANGII treatment, and subsequent hypertension and cardiac hypertrophy, could promote cancer growth and metastasis. Methods ANGII (2000ng.kg-1.min-1, 4w) was administered to 10w old C57B6/J mice using subcutaneous osmotic minipumps. After 3w, 5*10^5 Lewis lung carcinoma (LLC) cells or 2*10^5 MC38 colon cancer cells were injected onto the right flank of the mice. Tumor growth was monitored over 21d using a digital caliper. Tumor volume was calculated using the following formula: Length × width² × 0.5 On day 22, mice were sacrificed for further post-mortem analysis. Cardiac echography was performed after 3w of ANGII treatment and before sacrifice to assess cardiac function (data not shown). To assess the formation of cardiac fibrosis trichrome staining’s were performed. In addition, the effect of ANGII on LLC metastasis was investigated. Mice were treated with ANGII as described above. LLC cells, 2*10^6, were injected intravenously (i.v.). Mice were sacrificed 21d after cell injection. Metastatic growth was visualized and quantified by organ weighing and H&amp;E staining. Results LLC tumor growth was significantly increased by ANGII treatment. In addition, post-mortem tumor weight was increased (0.62 ± 0.05 g control vs. 1.17 ± 0.24 g ANGII). Furthermore, we found lung weight increased in the ANGII-treated group injected i.v. with LLC cells, indicating an increase in metastatic growth (0.41 ± 0.08 g control vs. 0.57 ± 0.04 g ANGII). Interestingly, MC38 tumor growth decreased in the ANGII treated group as portrayed by the tumor weight (0.42 ± 0.06 g control vs. 0.19 ± 0.05 g ANGII). Figure 1 shows the tumor growth over time and tumor volume, weight post-mortem. Conclusion Our data suggest a role for ANGII in CVD-enhanced cancer growth, but also that this effect is not universal, illustrated by a differential effect of ANGII on distinct cancer types. Although further investigation is required to unravel the role of ANGII, screening cancer patients with CVD comorbidities for ANGII involvement might be warranted.

Left atrial strain differences between hypertensive and sarcomeric left ventricular hypertrophy: a sign of sarcomeric auricular myopathy?

Abstract Introduction In clinical practice, left ventricular (LV) hypertrophy is a common finding that can be caused by physiologic or pathologic conditions. An etiologic diagnosis is extremely important because it may change the prognosis and management of the patient and his family. Left atrial (LA) dysfunction is common due to diastolic dysfunction but, in patients with sarcomeric LV hypertrophy, primary cardiomyopathy disease could also be present. Purpose To evaluate if there are differences in LA function between arterial hypertension (HT) and hypertrophic cardiomyopathy (HCM) patients. Methods 73 patients with HCM (according to ESC guidelines criteria) and 82 patients with HT (under treatment with ≥1 hypertensive drug for ≥3 months) and ≥13mm of LV hypertrophy underwent an echocardiography to assess LA function with strain analysis and LV diastolic function. Continuous normally distributed variables were compared with T-student test and categoric variables with square-chi or exact Fisher test if required, accepting as significant a p-value &amp;lt;0.05. Results Globally, HCM patients showed thicker LV walls and larger LA indexed volumes (18.7±4.7 vs. 13.3±0,8 mm and 44.9±20.7 vs. 30.7±8.8 ml/m2, p&amp;lt;0.000 for both). Also, HCM patients presented diastolic dysfunction and atrial fibrillation history in a higher frequency (31 vs. 7.6% and 16.4% vs. 0%, p&amp;lt;0.000 for both). LA strain was significantly lower in HCM patients as compared to the HT group (LA contractile 11.5±5.8 vs. 17.2±4.4, p&amp;lt;0.000; LA conduit 12.2±5.4 vs. 13.3±3.8, p=0.041; and LA reservoir 23.9±8.7 vs. 31.1±5.9, p&amp;lt;0.000). In the subgroup of patients with moderate-severe LV hypertrophy (&amp;lt;17mm) and no significant mitral regurgitation (n=103; HCM=21, HT=82), LA contractile strain remained lower in HCM as compared to HT patients (13.2±4.8% vs. 17.2±4.4%, p&amp;lt;0.000) (figure 1); without differences in diastolic dysfunction, LA volumes, significant mitral regurgitation or atrial fibrillation history. Conclusions Our results show that LA strain is more impaired in HCM patients as compared to HT patients. Specifically, contractile LA strain remained lower even in those patients with moderate-severe LV hypertrophy, despite having similar LV diastolic function, LA indexed volumes, significant mitral regurgitation, or atrial fibrillation history. These findings could be caused by HCM involvement of the LA myocytes. In the context of moderate-severe hypertrophy of unknown origin with non-significant mitral regurgitation, the detection of abnormally reduced LA strain could indicate the presence of an HCM.Figure 1

Parathyroid hormone exacerbates pulmonary hypertension via parathyroid hormone receptors on pulmonary artery smooth muscle cells

Abstract Background Pulmonary hypertension (PH) is a right heart failure disease and can be fatal. Parathyroid hormone (PTH) is a bone metabolism hormone and regulates calcium and phosphorus homeostasis. Previous studies have suggested that PTH affects the cardiovascular system and influences cardiovascular diseases. We hypothesized that PTH may play a role in the pathogenesis of PH. Purpose This study aimed to investigate whether PTH has a critical role in pulmonary hemodynamics. Method Serum PTH levels were measured in patients with PH or suspected PH undergoing right heart catheterization. We tested whether the regulation of PTH and the PTH receptor (PTH1R) affected PH in hypoxia (Hx)-induced PH model mice and Sugen/hypoxia (SuHx)-induced PH model ras. Hx mice were treated with PTH daily for 3 weeks or with an inhaled AAV-shRNA system to knockdown PTH1R expression in the lung. SuHx rats underwent parathyroidectomy (PTx). We measured physical data and right ventricular systolic pressure (RVSP) in these models. Human pulmonary artery smooth muscle cells (PASMCs) were cultured and treated with PTH to examine the direct effects of PTH. Result In the clinical study, we enrolled 30 participants and found serum PTH levels correlated with mean pulmonary artery pressure (r = 0.67) and pulmonary vascular resistance (r = 0.62). The ROC curve showed a cut-off PTH level of 46.0 pg/mL (68.2% sensitivity, 100% specificity) to predict PH. In animal models, PTH treatment exacerbated right ventricular hypertrophy and increased right ventricular systolic pressure (RVSP) in Hx mice compared with non-treated Hx mice (Figure 1). In contrast, knockdown of PTH1R in the lungs improved PH in Hx mice, and PTx significantly suppressed PH in SuHx rats (Figure 2). PTH promoted migration and proliferation through PTH receptor-ERK signaling in PASMCs. Conclusion Our clinical and experimental data showed that PTH exacerbates PH and suggest that PTH/PTH1R signaling would be a new target for PH treatment.

Gene-echocardiography: unmasking the covert role of fatty acid metabolism gene mutations in adult cardiomyopathy

Abstract Background Although the role of fatty acid metabolic deficiencies in cardiomyopathy is established, the precise identity of causative genes and their respective phenotypes in adult cardiomyopathy remains unclear. Methods We implemented a combination of echocardiography and whole exome sequencing in clinically diagnosed cardiomyopathy patients to uncover this relationship. This involved recording cardiac phenotypes, identifying genes associated with disrupted fatty acid metabolism, and subsequently followed up with these patients. Results Out of 802 cardiomyopathy patients, 27 exhibited mutations in genes tied to fatty acid metabolism. Specifically, 16 patients demonstrated a hypertrophic cardiomyopathy (HCM) phenotype, and 11 showed a dilated cardiomyopathy (DCM) phenotype. The implicated genes were SLC22A5 (n=7), ACADVL (n=6), ACADS (n=4), ACADM (n=3), SLC25A20 (n=3), ACADL (n=2), HADH (n=1), and AGK (n=1), with a higher prevalence in males. Among these, the SLC22A5 mutation was predominant and correlated with HCM phenotype. Notably, compound mutations were frequently observed (16/27), leading to earlier disease onset and diminished aortic sinus dimension. Further investigation showed that smaller aortic sinus dimensions resulted from abnormal left ventricular myocardial work. HCM phenotype mutation carriers showed more consistent left ventricular hypertrophy and a higher probability of right ventricular hypertrophy, while DCM phenotype mutation carriers exhibited impaired contractile function across all left ventricle segments. After a 24-month follow-up, the DCM phenotype group demonstrated higher cardiovascular risk, including two fatalities. Conclusion Our investigation highlights the significant prevalence of mutations related to abnormal fatty acid metabolism in adult cardiomyopathy patients, underscoring the utility of a gene-echocardiography approach for diagnosis.

Protective role of Metrnl on macrophage recruitment during the acute inflammatory phase in a mouse model of myocardial infarction

Abstract Introduction Meteorin-like protein (Metrnl) is a cytokine involved in the attenuation of inflammation. Previously, a cardioprotective role of Metrnl against cardiac hypertrophy and ischemia/reperfusion has been described. After myocardial infarction (MI), macrophages recruited from the spleen, and their capacity to shift from inflammatory (M1) to reparative (M2) phases determines the fate of cardiac repair. Purpose The aim of this study was to analyse the function of Metrnl in a mouse model of permanent MI during the acute inflammatory phase. Methods Wild-type (WT), Metrnl Knock-out (Metrnl-/-) and Metrnl-reconstituted Metrnl-/- mice (AAV9-Metrnl, with myocardial-specific tropism) were subjected to MI by coronary artery ligation. After 4 days, cardiac function was assessed using echocardiography at baseline and 4 days post-MI. Monocyte populations were analysed in spleen and blood by flow cytometry, and macrophages infiltrating the infarcted myocardium by gene expression analyses. Results Echocardiographic analysis demonstrated that Metrnl deficiency led to cardiac dysfunction (FAC p=0.02) accompanied by myocardial dilation 4 days post-MI (EDV p=0.02; ESV p=0.01). On the contrary, the overexpression of Metrnl in the myocardium of AVV9-Metrnl mice restored cardiac function compared to Metrnl-/- group (FAC p=0.01, EDV p=0.04, ESV p=0.09). Furthermore, we observed a reduction in splenic monocytes (CD11b+F4/80+) in Metrnl-/- mice compared to the WT group at 4 days post-MI (p=0.06). In particular, a significant decrease in pro-inflammatory Ly6CHigh and CD86+ monocytes was noted in the spleens of Metrnl-/- mice compared to the WT group (p=0.03; p=0.04 respectively), suggesting their mobilization out of the spleen, but not in the AVV9-Metrnl group. Although the total number of Ly6CHigh and Ly6CLow monocytes in the bloodstream was similar in all groups, there was a trend to different expression in the CCR2 and CCR5 chemokine receptors (p=0.07; p=0.06 respectively). At the same time, M1 macrophage recruitment chemokines (CCL2) and inflammatory markers (TNFα) were significantly induced in the ischemic area of the infarcted myocardium compared to the remote zone in the WT and Metrnl-/- groups (CCL2 p=0.03; p=0.01 respectively; TNFα p=0.008;p=0.04 respectively). In contrast, TNFα and CCL2 genes were not induced in the ischemic area of AVV9-Metrnl mice. Regarding M2 macrophages, the Arg1 marker was significantly reduced in the ischemic zone of Metrnl-/- mice compared to the WT group (p= 0.01), while in the AVV9-Metrnl group was recovered (p= 0.04). Conclusions Our results demonstrate that the absence of Metrnl promotes the recruitment of inflammatory macrophages to the ischemic myocardium and is associated to cardiac dysfunction.

Effect and mechanism of Adipokine Omentin-1 on cardiac hypertrophy in heart failure with preserved ejection fraction

Abstract Background Omentin-1 secreted by epicardial adipose tissue can inhibit ventricular remodeling and improve early cardiac function after myocardial infarction. Our previous studies have identified the omentin-1 receptor as integrin receptors αvβ3 and αvβ5. However, the effect of omentin-1 on heart failure with preserved ejection fraction (HFpEF) remains poorly understood. Purpose The present study aims to study the role and mechanism of omentin-1 in cardiac function and myocardial cell structure in HFpEF. Methods and Results The influences of omentin-1 were investigated in HFpEF mice (HFD (60% calories from lard) and L-NAME (0.5 g/L in drinking water)), which were treated in vivo. Echocardiography showed better diastolic function in HFpEF mice treated with omentin-1 (5 ug/kg/h) subcutaneously for 4 weeks, and tissue staining showed alleviated myocardial fibrosis and myocardial hypertrophy. The RNA sequencing analysis revealed variations in the gene expression related to ketone body metabolism in HFpEF mice after omentin-1 treatment (600 ng/ml). The supernatant was obtained from mouse bone marrow macrophages treated with ultrapure endotoxin and ATP and was utilized as the macrophage-conditioned medium for culturing primary cardiomyocytes, which were stimulated with isoproterenol for 48 hours to construct the HFpEF cardiomyocyte model. In the heart tissue of HFpEF mice and HFpEF cardiomyocytes treated with omentin-1, there was a notable increase in the expression of a pivotal enzyme of ketone body metabolism- succinyl-CoA transferase (SCOT), and a decrease in the expression of hypertrophy signal. The myocardial hypertrophy model was established by stimulating the myocardial cell line H9C2 with isoproterenol. Following the inhibition of the integrin receptor and PI3K-AKT pathway, the impacts of omentin-1 on SCOT and myocardial hypertrophy signal expression in hypertrophic cardiomyocytes were eliminated. Conclusion This study provides evidence for the effects of omentin-1 on cardiac function and myocardial structure in HFpEF and proposes that omentin-1 may stimulate the downstream PI3K/AKT pathway via integrin receptors on cardiomyocytes, leading to increased expression of SCOT and improvement of cardiomyocyte hypertrophy.

Deletion of nephrocystin 4 exacerbates cardiac function and survival rate in a mouse model of cardio-renal syndrome

Abstract Background Cardiorenal syndrome (CRS), characterized by cardiac and renal dysfunction, is an increasing health problem associated with high mortality rate. Nephrocystin 4 (NPHP4) gene is the major cause of end-stage renal disease in children. We have reported NPHP4 single nucleotide polymorphism is the genetic risk for CRS and subsequent cardiovascular events in general population. However, the functional role of Nphp4 in the development of CRS has never been examined yet. Methods and Results We generated systemic Nphp4 knockout (KO) mice deleting exon 3 to 8 using CRISPR-Cas9 system. RNA sequence analysis of heart and kidney tissues demonstrated that gene-sets related to mitochondrial function were significantly downregulated in Nphp4 KO mice compared to their wild-type (WT) littermates. Nphp4 KO mice showed less cardiac hypertrophy, however, exacerbated cardiac function and survival compared to WT mice in a CRS model induced by thoracic transverse aortic constriction. Nphp4 located in endosome and cell membrane in H9C2 cardiomyocytes. Immunoprecipitation confirmed protein interaction between Nphp4 and HECT-type E3 ligase Itch. Furthermore, we found that Itch targeted Lats2 and insulin-like growth factor-1 receptor in cardiomyocytes. Knockdown of Nphp4 activated Hippo signaling and worsened mitochondrial function in H9C2 cardiomyocytes through the inhibition of Itch-dependent Lats2 degradation. Knockdown of Nphp4 inhibited insulin-like growth factor-1 signaling through the disturbance of Itch-mediated endosome function. Conclusions Deletion of Nphp4 impaired compensatory cardiac hypertrophy and exacerbated cardiac function and survival in a mouse CRS model through mitochondrial dysfunction. Nphp4 mediated Hippo signaling and insulin-like growth factor-1 signaling through the interaction with Itch. NPHP4 could be the novel therapeutic target in CRS.figure1figure2

Milk-derived extracellular vehicles alleviate heart failure with preserved ejection fraction by modulating gut microbiota

Abstract Background Accounting for around 50% of human heart failure, heart failure with preserved ejection fraction (HFpEF) is driven by complex and heterogeneous pathological factors, including gut microbiome dysbiosis. We have previously reported that milk-derived extracellular vesicles (mEVs) modulate the gut microbiota in inflammatory bowel disease. However, whether mEVs can affect gut microbiota and thereby alleviate HFpEF remains unexplored. Aims We aim to uncover potential therapeutic effects of mEVs on HFpEF and if so, the underlying mechanisms. Methods The HFpEF mouse model was generated by feeding C57/B6 mice on a high-fat diet and L-NAME for 15 weeks. Mouse feces samples were analyzed to detect the presence of gut dysbiosis in HFpEF. Mice received bovine mEVs through oral gavage. Heart function was assessed with echocardiography. Mouse feces and plasma were collected to analyze gut microbiota and metabolomics, respectively. Results Gut microbiota was disturbed in HFpEF mice. Oral administration of mEVs effectively attenuated heart failure which was evidenced by less bodyweight gain, reduction in cardiac hypertrophy and lung weight, and improvement in cardiac function parameters such as ratios of E/A (1.8 vs. 1.5, p&amp;lt;0.05) and E/E’ (40 vs. 27, p&amp;lt;0.05). Moreover, the increase in mouse blood pressure in HFpEF was also inhibited upon treatment (SBP 130mmHg vs. 100mmHg, DBP 90mmHg vs. 75mmHg, p&amp;lt;0.05). Mechanistically, we ruled out the possibility of direct action of mEVs on the heart as orally administered mEVs were only distributed in the intestine. On the other hand, mEVs restored gut microbiota by increasing the abundance of beneficial bacteria such as Lachnospiraceae. As a result, oral administration of mEVs elevated blood levels of Lachnospiraceae metabolite, butyric acid, a type of short-chain fatty acid. To confirm the butyric acid-mediated heart-protective effects of mEVs, we administered butyric acid to HFpEF mice. Strikingly, butyric acid largely reproduced the therapeutic effects of mEVs on HFpEF. Conclusions Oral administration of mEVs restores gut microbiota dysbiosis, thereby attenuating heart failure in HFpEF. mEVs may represent a new biological therapeutic for the treatment of HFpEF.

Mammalian Diaphanous-related formin 1 (mDia1) inducing diabetic cardiomyopathy by regulating metabolic reprogramming

Abstract Background Mammalian Diaphanous-related formin 1 (mDia1) is one of the formin family proteins and acts as a rho-effector molecule which is involved in actin organization. Previous studies showed that mDia1 aggravated compensatory cardiac hypertrophy in response to pressure overload. However, the role of mDia1 in diabetic cardiomyopathy and its mechanisms remain elusive. Objective To clarify the mechanisms of mDia1 in DCM through mediating metabolic reprogramming. Methods 5-week-old of mDia1 ko mice were used to induce DCM by feeding high-fat diet (HFD) for 16 weeks. The blood glucose and body weight of the mice were measured regularly. Echocardiography was used to evaluate cardiac function. HE and WGA staining were used to evaluate hypertrophy of cardiomyocytes. Transmission electron microscopy and mitotracker staining were used to observe the morphology of mitochondrial in heart. Proteomics and metabolomics were used to explore the metabolites in hearts of mice. Primary neonatal cardiomyocytes were isolated and stimulated with 35 mM glucose and 250 μM palmitate in vitro. Adenovirus expressing shRNA of mDia1 was used to knockdown mDia1 in cardiomyocytes. Mitochondria were isolated from primary cardiomyocytes to verify the translocation of mDia1. Co-Immunoprecipitation was used to confirm the interaction between mDia1 with succinate dehydrogenase subunits A (SDHA). Results mDia1 had no effects to blood glucose and body weight after 16-week HFD feeding. Loss of mDia1 ameliorated diastolic dysfunction in DCM mice with shorter isovolumic relaxation time (IVRT) and increased E/A ratio in left ventricular. In addition, cardiac hypertrophy was significantly improved in mDia1 ko mice. mDia1 deficiency tended to maintain the normal mitochondrial structure. Results of proteomics showed that mDia1 was involved in mitochondrial function, ATP synthesis and metabolic pathways. Metabolomics showed that HFD induced accumulation of α-ketoglutaric acid in wild type mice compared with mDia1 ko mice. However, mDia1 ko significantly increased fumaric acid but did not affect succinyl-CoA and succinic acid compared with wild type mice. Furthermore，we found that mDia1 translocated into mitochondrial with high glucose and palmitate stimuli. Results of CoIP showed mDia1 interacted with SDHA both in cardiomyocytes and HEK293 cells. Conclusions mDia1 deteriorated DCM through translocating into mitochondrial and interacting with SDHA, a process dependent on metabolic pathways.Figure of Mechanism

Anti-fibrotic effects of the sirt6-activator mdl-800 in cardiac stromal cells

Abstract Background Epigenetic changes are among the molecular substrates of cellular stress responses and tissue remodeling in heart failure progression. The sirtuin family of NAD+-dependent histone and non-histone protein deacetylases exert a protective anti-fibrotic role by negatively modulating the inflammatory response and by positive regulation of autophagy-related genes. Sirtuin6 (SIRT6) stands out as a key cardiac protector that can mitigate aging-induced cardiomyocyte senescence and cardiac hypertrophy. Cardiac stromal cells (CSCs) play a pivotal role in fibrosis and remodeling, regulating the composition and stiffness of the extracellular matrix (ECM). Autophagy enhancement has anti-fibrotic effects in CSCs, but the specific role of SIRT6 modulation in CSCs remains unexplored. Purpose To investigate the biological effects of MDL-800, a synthetic allosteric SIRT6 activator, on the stress response and fibrotic activation of CSCs. Methods CSCs were isolated from 4-week-old C57Bl6J mice by explant culture and stimulated with 10ng/ml of TGF-beta1 (TGFb1) up to 72h to induce fibrotic activation. CSCs were treated with MDL-800 up to 10µM and up to 72h, analyzed for cell viability, gene and protein expression levels. Results TGFb1 treatment led to a 0.64-fold reduction in SIRT6 gene expression after 24h. The MTS assay was used to assess a viability dose-response to MDL-800 up to 72h of treatment. The non-toxic concentrations of 2.5µM and 5µM were selected for further experiments (2.5µM vs CTR 0.97-fold and 5µM vs CTR 0.92-fold, normalized OD vs t0). Co-treatment of 5µM MDL-800 with TGFb1 for 72h resulted in a dose-dependent decrease in the expression of TGFb1-induced fibroblast activation markers, as confirmed by immunofluorescence staining for aSMA (TGFb1 vs CTR 2.21-fold, p&amp;lt;0.05; 5µM vs TGFb1 0.46-fold, p&amp;lt;0.05, N=4; mean fluorescence intensity). The anti-fibrotic effect mediated by MDL-800 was further validated by real-time PCR indicating a reduction in the mRNA expression of multiple fibrotic markers, including ACTA2 (TGFb1 vs CTR 1.67-fold, 5µM vs TGFB 0.29-fold; N=2), COL1a1 (TGFb1 vs CTR 1.32-fold, 5µM vs TGFb1 0.87-fold; N=2) COL3a1 (TGFb1 vs CTR 1.06-fold, 5µM vs TGFb1 0.43-fold; N=2) and POSTN (TGFb1 vs CTR 6.37-fold, 5µM vs TGFb1 0.23-fold; N=2). Treatment with 5µM MDL-800 demonstrated an increase in SIRT6 gene expression, suggesting a transcriptional modulation (TGFb1 vs CTR 0.95-fold, 5µM vs TGFb1 1.68-fold; N=2). Western Blot analyses showed an increase in protein levels of the autophagosome marker LC3-II following treatment with 5µM MDL-800 (TGFb1 vs CTR 0.95-fold; 5µM vs TGFb1 3.01-fold), suggesting that autophagy enhancement may be a potential mechanism for the observed anti-fibrotic effects. Conclusion MDL-800 treatment in CSCs is associated with a dose-dependent reduction of TGFb1-induced fibrotic markers and to increased levels of the autophagy marker, suggesting its potential use as an anti-fibrotic molecule for the heart.

Moderate intensity exercise training ameliorates the heart failure with preserved ejection fraction phenotype in a preclinical model by improving cardiometabolic fitness

Abstract Introduction and Aim Exercise intolerance is a hallmark feature of patients with heart failure with preserved ejection fraction (HFpEF).While clinical evidence suggests potential benefits of exercise training in HFpEF, its mechanisms remain largely unknown.In this study, we used a translationally relevant murine model of cardiometabolic HFpEF(1) to assess whether moderate intensity continuous training(MICT) can ameliorate the HFpEF phenotype in mice and promote cardiometabolic health. Methods Twenty-five adult, male C57BL/6N were fed with the combination of high fat diet(HFD;D12492,Research diet)and L-NAME(0.5 g/L,in drinking water) for 15 weeks to elicit HFpEF as previously described(1).After the establishment of the HFpEF phenotype, mice were randomized in two groups:sedentary(SED,n= 10) and exercised(MICT,n=15)mice.MICT was carried out according to the protocol:running on 10-degree positive inclination treadmill for 8 consecutive weeks,5 times/week,60 minutes/day,at a speed gradually increasing from 0.1 to 0.2 m/sec on a weekly basis.Morphometry, echocardiography(TTE),isoproterenol-induced stress echocardiography(SE),time domain nuclear magnetic resonance, and treadmill exhaustion tests were performed at the beginning and end of MICT.Additionally, at the end of MICT blood and tissues were collected for proteomics analysis(Fig1).Non-trained male C57BL/6N mice(37w) were used as controls for the HFpEF mice. Results Before randomization, all HFpEF mice were similar in terms of phenotypic characteristics. Compared to SED mice, MICT induced a significantly decrease in body weight driven by a reduction of total fat mass with an increased in lean mass(Fig2A+B).Interestingly, MICT had no impact on skeletal muscle mass for all different muscle groups evaluated (extensor digitorum longus, soleus and tibialis anterior).Importantly, MICT led to a significant improvement in exercise capacity in HFpEF mice, as shown by increased running distance and time, surpassing even the running distance seen in non-HFpEF mice (SED:62.8±18.7,MICT:305.7±13.9,non-HFpEF mice: 129.72±15.2meters,p&amp;lt;0.001).Preclinical surrogate of HFpEF such as pulmonary congestion, evaluated by index lung weights, improved after aerobic training.Following MICT there was a marked improvement in diastolic dysfunction(measured by E/E’ratio) both at rest(SED:36.5±3.3,MICT:23.3±5.09,p&amp;lt;0.001) and after isoproterenol challenge(SED:42.6±15.1,MICT:26.09±3.75,p&amp;lt;0.001)(Fig2C).Moreover, the wet cardiac mass was lower in the MICT group(Fig2A), suggesting potential amelioration in cardiac hypertrophy following aerobic training. Conclusion Eight weeks of supervised MICT on treadmill improves functional status, exercise capacity, and diastolic function in a cardiometabolic HFpEF murine model.The most significant effects were seen on weight loss and fat mass reduction.Our findings suggest a beneficial impact of aerobic exercise in mitigating HFpEF by improving metabolic fitness in the preclinical HFpEF model.Fig1-Study DesignFig2-Characteristics SED vs MICT groups