PDE9A Inhibition Improves Coronary Microvascular Rarefaction and Left Ventricular Diastolic Dysfunction in the ZSF1 Rat Model of HFpEF.

OBJECTIVE: Heart failure with preserved ejection fraction (HFpEF) commonly arises from comorbid diseases, such as hypertension, obesity, and diabetes mellitus. Selective inhibition of phosphodiesterase 9A (PDE9A) has emerged as a potential therapeutic approach for treating cardiometabolic diseases. Coronary microvascular disease (CMD) is one of the key mechanisms contributing to the development of left ventricular (LV) diastolic dysfunction in HFpEF. Our study aimed to investigate the mechanisms by which PDE9A inhibition could ameliorate CMD and improve LV diastolic function in HFpEF. METHODS AND RESULTS: The obese diabetic Zucker fatty/spontaneously hypertensive heart failure F1 hybrid (ZSF1) rat model of HFpEF was employed in which it was found that a progressively developing coronary microvascular rarefaction is associated with LV diastolic dysfunction when compared to lean, nondiabetic hypertensive controls. Obese ZSF1 rats had an increased cardiac expression of PDE9A. Treatment of obese ZSF1 rats with the selective PDE9A inhibitor, PF04447943 (3 mg/kg/day, oral gavage for 2 weeks), improved coronary microvascular rarefaction and LV diastolic dysfunction, which was accompanied by reduced levels of oxidative and nitrosative stress markers, hydrogen peroxide, and 3-nitrotyrosine. Liquid chromatography-mass spectrometry (LC-MS) proteomic analysis identified peroxiredoxins (PRDX) as downregulated antioxidants in the heart of obese ZSF1 rats, whereas Western immunoblots showed that the protein level of PRDX5 was significantly increased by the PF04447943 treatment. CONCLUSIONS: Thus, in the ZSF1 rat model of human HFpEF, PDE9A inhibition improves coronary vascular rarefaction and LV diastolic dysfunction, demonstrating the usefulness of PDE9A inhibitors in ameliorating CMD and LV diastolic dysfunction through augmenting PRDX-dependent antioxidant mechanisms.

The Impact of Body Mass Index on the Mortality of Myocardial Infarction Patients With Nonobstructive Coronary Arteries.

OBJECTIVES: Myocardial infarction without significant stenosis or occlusion of the coronary arteries carries a high risk of recurrent major adverse cardiovascular events and poor prognosis. This study aimed to investigate the association between body mass index and outcomes in patients with a suspected myocardial infarction with nonobstructive coronary artery disease (MINOCA). METHODS: Patients were recruited at Bergmannsheil University Hospital from January 2010 to April 2021. The primary outcomes were in-hospital and long-term mortality. Secondary outcomes consisted of adverse events during hospitalization and during follow-up. RESULTS: A total of 373 patients were included in the study, with a mean follow-up time of 6.2 years. The patients were divided into different BMI groups: < 25 kg/m² (n = 121), 25-30 kg/m² (n = 140), and > 30 kg/m² (n = 112). In-hospital mortality was 1.7% versus 2.1% versus 4.5% (p = 0.368). However, long-term mortality tended to be higher in the < 25 kg/m² group compared to the 25-30 and > 30 kg/m² groups (log-rank p = 0.067). Subgroup analysis using Kaplan-Meier analysis showed a higher rate of cardiac cause of death in the < 25 kg/m² group compared to the 25-30 and > 30 kg/m² groups: 5.7% versus 1.1% versus 0.0% (log-rank p = 0.042). No significant differences were observed in other adverse events between the different BMI groups during hospitalization and long-term follow-up. CONCLUSIONS: Patients with a BMI < 25 kg/m² who experience a suspected myocardial infarction without significant coronary artery disease may have higher all-cause mortality and cardiovascular cause of death. However, further data are needed to confirm these findings.

Roles and Mechanisms of Dopamine Receptor Signaling in Catecholamine Excess Induced Endothelial Dysfunctions.

Endothelial dysfunction may contribute to pathogenesis of Takotsubo cardiomyopathy, but mechanism underlying endothelial dysfunction in the setting of catecholamine excess has not been clarified. The study reports that D1/D5 dopamine receptor signaling and small conductance calcium-activated potassium channels contribute to high concentration catecholamine induced endothelial cell dysfunction. For mimicking catecholamine excess, 100 µM epinephrine (Epi) was used to treat human cardiac microvascular endothelial cells. Patch clamp, FACS, ELISA, PCR, western blot and immunostaining analyses were performed in the study. Epi enhanced small conductance calcium-activated potassium channel current (ISK1-3) without influencing the channel expression and the effect was attenuated by D1/D5 receptor blocker. D1/D5 agonists mimicked the Epi effect, suggesting involvement of D1/D5 receptors in Epi effects. The enhancement of ISK1-3 caused by D1/D5 activation involved roles of PKA, ROS and NADPH oxidases. Activation of D1/D5 and SK1-3 channels caused a hyperpolarization, reduced NO production and increased ROS production. The NO reduction was membrane potential independent, while ROS production was increased by the hyperpolarization. ROS (H2O2) suppressed NO production. The study demonstrates that high concentration catecholamine can activate D1/D5 and SK1-3 channels through NADPH-ROS and PKA signaling and reduce NO production, which may facilitate vasoconstriction in the setting of catecholamine excess.

Predictors of ventricular tachyarrhythmia in patients with a wearable cardioverter defibrillator: an international multicenter registry.

BACKGROUND AND AIMS: Wearable cardioverter defibrillator (WCD) can protect patients from sudden cardiac death due to ventricular tachyarrhythmias and serve as a bridge to decision of definite defibrillator implantation. The aim of this analysis from an international, multicenter WCD registry was to identify predictors of sustained ventricular tachycardia (VT) and/or ventricular fibrillation (VF) in this population. METHODS: One thousand six hundred seventy-five patients with WCD were included in a multicenter registry from 9 European centers, with a median follow-up of 440 days (IQR 120-893). The primary study end point was the occurrence of sustained VT/VF. RESULTS: Sustained VT was detected by WCD in 5.4% and VF in 0.9% of all patients. Of the 30.3% of patients receiving ICD implantation during follow-up, sustained VT was recorded in 9.3% and VF in 2.6%. Non-ischemic cardiomyopathy (HR 0.5, p < 0.001), and medication with angiotensin-converting enzyme inhibitors (HR 0.7, p = 0.027) and aldosterone antagonists (HR 0.7, p = 0.005) were associated with a significantly lower risk of VT/VF. CONCLUSIONS: Patients who received WCD due to a transient increased risk of sudden cardiac death have a comparatively lower risk of VT/VF in the presence of non-ischemic cardiomyopathy. Of note, optimal medical treatment for heart failure not only results in an improvement in left ventricular ejection fraction but also in a reduction in the risk for VT/VF.

No beneficial use of the wearable cardioverter defibrillator among patients suffering from inherited and congenital heart disease: data from a European multicenter registry.

Background: Data on the use of the wearable cardioverter defibrillator in patients suffering from inherited and congenital heart disease are limited. Consequently, evidence for guideline recommendations in this patient population is lacking. Methods: In total 1,675 patients were included in a multicenter registry of eight European centers. In the present cohort, we included 18 patients suffering from congenital and inherited heart disease. Results: Nine patients (50%) were male with a mean age of 41.3 ± 16.4 years. Four patients suffered from hypertrophic cardiomyopathy (HCM), four patients suffered from non-compaction cardiomyopathy (NCCM), two patients were diagnosed with arrhythmogenic right ventricular cardiomyopathy (ARVC) and one patient suffered from muscular dystrophy of the limb-girdle type with cardiac involvement, secondary cardiomyopathy. Three patients presented with Brugada syndrome (BrS). One patient suffered from long-QT syndrome type 1 (LQTS1). Furthermore, two patients had congenital heart defects and one patient suffered from cardiac sarcoidosis (CS). There were no appropriate/inappropriate shocks with the WCD in this cohort. One patient had recurrent self-limiting sustained ventricular tachycardia during the wear time, but actively inhibited a shock and was hospitalized. The compliance rate in this cohort was 77.8% with a mean wear time of 45.3 ± 26.9 days with a mean follow-up time of 570 ± 734 days. 55.6% (10/18) of the patients received an ICD after WCD wear time. Conclusions: This retrospective study of patients with inherited and congenital heart disease shows that WCD use is not beneficial in the majority of patients with inherited and congenital heart disease.

Prognostic Implications of Coronary Artery Sclerosis in Troponin-Positive Patients with Non-Obstructive Coronary Arteries.

INTRODUCTION: Coronary sclerosis is a risk factor for the progression to obstructive coronary artery disease (CAD). However, understanding its impact on the outcomes of patients with myocardial infarction and non-obstructive coronary arteries is limited. This study aimed to explore the prognostic influence of coronary sclerosis on in- and out-of-hospital events in troponin-positive patients with non-obstructive coronary arteries. METHODS: This study was a retrospective cohort analysis based on prospectively collected data. A total of 24,775 patients who underwent coronary angiography from 2010 to 2021 in a German university hospital were screened, resulting in a final study cohort of 373 troponin-positive patients with non-obstructive coronary arteries and a follow-up period of 6.2 ± 3.1 years. Coronary sclerosis was defined as coronary plaques without angiographically detectable stenotic lesions of 50% or more in the large epicardial coronary arteries. The primary study endpoint was the occurrence of in-hospital events. Secondary endpoints included events during follow-up. RESULTS: Patients with coronary sclerosis were significantly older (70 ± 12 vs. 58 ± 16 years, p < 0.001), had ST-segment elevation less frequently on electrocardiogram (9.4% vs. 18.7%, p = 0.013), and suffered more often from diabetes mellitus (23.3% vs. 13.1%, p = 0.009), arterial hypertension (79.6% vs. 59.8%, p < 0.001), chronic obstructive pulmonary disease (17.1% vs. 9.4%, p = 0.028), chronic kidney disease (22.2% vs. 8.4%, p < 0.001), atrial fibrillation (19.8% vs. 12.2%, p = 0.045), and valvular diseases than patients without CAD. Patients with coronary sclerosis were more likely to receive medication for primary/secondary prevention on admission and at discharge. The incidence of in- and out-of-hospital events was significantly higher in patients with coronary sclerosis (in-hospital: 42.8% vs. 29.9%, p = 0.010; out-of-hospital: 46.0% vs. 26.1%, p < 0.001). Mortality rates tended to be higher in the coronary sclerosis group (29.4% vs. 20.0%, p = 0.066). CONCLUSION: Patients diagnosed with coronary sclerosis presented a higher incidence of comorbidities and increased medication use, and experienced higher rates of both in-hospital and out-of-hospital events, primarily due to the clustering of cardiovascular risk factors.

Mechanisms of myocardial reverse remodelling and its clinical significance: A scientific statement of the ESC Working Group on Myocardial Function.

Cardiovascular disease (CVD) is the leading cause of morbimortality in Europe and worldwide. CVD imposes a heterogeneous spectrum of cardiac remodelling, depending on the insult nature, that is, pressure or volume overload, ischaemia, arrhythmias, infection, pathogenic gene variant, or cardiotoxicity. Moreover, the progression of CVD-induced remodelling is influenced by sex, age, genetic background and comorbidities, impacting patients' outcomes and prognosis. Cardiac reverse remodelling (RR) is defined as any normative improvement in cardiac geometry and function, driven by therapeutic interventions and rarely occurring spontaneously. While RR is the outcome desired for most CVD treatments, they often only slow/halt its progression or modify risk factors, calling for novel and more timely RR approaches. Interventions triggering RR depend on the myocardial insult and include drugs (renin-angiotensin-aldosterone system inhibitors, beta-blockers, diuretics and sodium-glucose cotransporter 2 inhibitors), devices (cardiac resynchronization therapy, ventricular assist devices), surgeries (valve replacement, coronary artery bypass graft), or physiological responses (deconditioning, postpartum). Subsequently, cardiac RR is inferred from the degree of normalization of left ventricular mass, ejection fraction and end-diastolic/end-systolic volumes, whose extent often correlates with patients' prognosis. However, strategies aimed at achieving sustained cardiac improvement, predictive models assessing the extent of RR, or even clinical endpoints that allow for distinguishing complete from incomplete RR or adverse remodelling objectively, remain limited and controversial. This scientific statement aims to define RR, clarify its underlying (patho)physiologic mechanisms and address (non)pharmacological options and promising strategies to promote RR, focusing on the left heart. We highlight the predictors of the extent of RR and review the prognostic significance/impact of incomplete RR/adverse remodelling. Lastly, we present an overview of RR animal models and potential future strategies under pre-clinical evaluation.

Small conductance calcium-activated potassium channel contributes to stress induced endothelial dysfunctions.

Patients with Takotsubo syndrome displayed endothelial dysfunction, but underlying mechanisms have not been fully clarified. This study aimed to explore molecular signalling responsible for catecholamine excess induced endothelial dysfunction. Human cardiac microvascular endothelial cells were challenged by epinephrine to mimic catecholamine excess. Patch clamp, FACS, ELISA, PCR, and immunostaining were employed for the study. Epinephrine (Epi) enhanced small conductance calcium-activated potassium channel current (ISK1-3) through activating α1 adrenoceptor. Phenylephrine enhanced edothelin-1 (ET-1) and reactive oxygen species (ROS) production, and the effects involved contribution of ISK1-3. H2O2 enhanced ISK1-3 and ET-1 production. Enhancing ISK1-3 caused a hyperpolarization, which increases ROS and ET-1 production. BAPTA partially reduced phenylephrine-induced enhancement of ET-1 and ROS, suggesting that α1 receptor activation can enhance ROS/ET-1 generation in both calcium-dependent and calcium-independent ways. The study demonstrates that high concentration catecholamine can activate SK1-3 channels through α1 receptor-ROS signalling and increase ET-1 production, facilitating vasoconstriction.

Catecholamine induces endothelial dysfunction via Angiotensin II and intermediate conductance calcium activated potassium channel.

Endothelial dysfunction contributes to the pathogenesis of Takotsubo syndrome (TTS). However, the exact mechanism underlying endothelial dysfunction in the setting of TTS has not been completely clarified. This study aims to investigate the roles of angiotensin II (Ang II) and intermediate-conductance Ca2+-activated K+ (SK4) channels in catecholamine-induced endothelial dysfunction. Human cardiac microvascular endothelial cells (HCMECs) were exposed to 100 µM epinephrine (Epi), mimicking the setting of TTS. Epi treatment increased the ET-1 concentration and reduced NO levels in HCMECs. Importantly, the effects of Epi were found to be mitigated in the presence of Ang II receptor blockers. Furthermore, Ang II mimicked Epi effects on ET-1 and NO production. Additionally, Ang II inhibited tube formation and increased cell apoptosis. The effects of Ang II could be reversed by an SK4 activator NS309 and mimicked by an SK4 channel blocker TRAM-34. Ang II also inhibited the SK4 channel current (ISK4) without affecting its expression level. Ang II could depolarize the cell membrane potential. Ang II promoted ROS release and reduced protein kinase A (PKA) expression. A ROS blocker prevented Ang II effect on ISK4. The PKA activator Sp-8-Br-cAMPS increased SK4 channel currents. Epinephrine enhanced the activity of ACE by activating the α1 receptor/Gq/PKC signal pathway, thereby promoting the secretion of Ang II. The study suggested that high-level catecholamine can increase Ang II release from endothelial cells by α1 receptors/Gq/PKC signal pathway. Ang II can inhibit SK4 channel current by increasing ROS generation and reducing PKA expression, thereby contributing to endothelial dysfunction.

Empagliflozin inhibits increased Na influx in atrial cardiomyocytes of patients with HFpEF.

AIMS: Heart failure with preserved ejection fraction (HFpEF) causes substantial morbidity and mortality. Importantly, atrial remodelling and atrial fibrillation are frequently observed in HFpEF. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have recently been shown to improve clinical outcomes in HFpEF, and post-hoc analyses suggest atrial anti-arrhythmic effects. We tested if isolated human atrial cardiomyocytes from patients with HFpEF exhibit an increased Na influx, which is known to cause atrial arrhythmias, and if that is responsive to treatment with the SGTL2i empagliflozin. METHODS AND RESULTS: Cardiomyocytes were isolated from atrial biopsies of 124 patients (82 with HFpEF) undergoing elective cardiac surgery. Na influx was measured with the Na-dye Asante Natrium Green-2 AM (ANG-2). Compared to patients without heart failure (NF), Na influx was doubled in HFpEF patients (NF vs. HFpEF: 0.21 ± 0.02 vs. 0.38 ± 0.04 mmol/L/min (N = 7 vs. 18); P = 0.0078). Moreover, late INa (measured via whole-cell patch clamp) was significantly increased in HFpEF compared to NF. Western blot and HDAC4 pulldown assay indicated a significant increase in CaMKII expression, CaMKII autophosphorylation, CaMKII activity, and CaMKII-dependent NaV1.5 phosphorylation in HFpEF compared to NF, whereas NaV1.5 protein and mRNA abundance remained unchanged. Consistently, increased Na influx was significantly reduced by treatment not only with the CaMKII inhibitor autocamtide-2-related inhibitory peptide (AIP), late INa inhibitor tetrodotoxin (TTX) but also with sodium/hydrogen exchanger 1 (NHE1) inhibitor cariporide. Importantly, empagliflozin abolished both increased Na influx and late INa in HFpEF. Multivariate linear regression analysis, adjusting for important clinical confounders, revealed HFpEF to be an independent predictor for changes in Na handling in atrial cardiomyocytes. CONCLUSION: We show for the first time increased Na influx in human atrial cardiomyocytes from HFpEF patients, partly due to increased late INa and enhanced NHE1-mediated Na influx. Empagliflozin inhibits Na influx and late INa, which could contribute to anti-arrhythmic effects in patients with HFpEF.

Ejection Fraction-Related Differences of Baseline Characteristics and Outcomes in Troponin-Positive Patients without Obstructive Coronary Artery Disease.

Background: The development and course of myocardial infarction with non-obstructive coronary artery (MINOCA) disease is still not fully understood. In this study, we aimed to examine the baseline characteristics of in-hospital outcomes and long-term outcomes of a cohort of troponin-positive patients without obstructive coronary artery disease based on different left ventricular ejection fractions (LVEFs). Methods and results: We included a cohort of 254 patients (mean age: 64 (50.8-75.3) years, 120 females) with suspected myocardial infarction and no obstructive coronary artery disease (MINOCA) in our institutional database between 2010 and 2021. Among these patients, 170 had LVEF ≥ 50% (84 females, 49.4%), 31 patients had LVEF 40-49% (15 females, 48.4%), and 53 patients had LVEF < 40% (20 females, 37.7%). The mean age in the LVEF ≥ 50% group was 61.5 (48-73) years, in the LVEF 40-49% group was 67 (57-78) years, and in the LVEF < 40% group was 68 (56-75.5) years (p = 0.05). The mean troponin value was highest in the LVEF < 40% group, at 3.8 (1.7-4.6) µg/L, and lowest in the LVEF ≥ 50% group, at 1.1 (0.5-2.1) µg/L (p = 0.05). Creatine Phosphokinase (CK) levels were highest in the LVEF ≥ 50% group (156 (89.5-256)) and lowest in the LVEF 40-49% group (127 (73-256)) (p < 0.05), while the mean BNP value was lowest in the LVEF ≥ 50% group (98 (48-278) pg/mL) and highest in the <40% group (793 (238.3-2247.5) pg/mL) (p = 0.001). Adverse in-hospital cardiovascular events were highest in the LVEF < 40% group compared to the LVEF 40-49% group and the LVEF ≥ 50% group (56% vs. 55% vs. 27%; p < 0.001). Over a follow-up period of 6.2 ± 3.1 years, the all-cause mortality was higher in the LVEF < 40% group compared to the LVEF 40-49% group and the LVEF ≥ 50% group. Among the different factors, LVEF < 40% and LVEF 40-49% were associated with an increased risk of in-hospital cardiovascular events in the multivariable Cox regression analysis. Conclusions: LVEF has different impacts on in-hospital cardiovascular events in this cohort. Furthermore, LVEF influences long-term all-cause mortality.

Impacts of gene variants on drug effects-the foundation of genotype-guided pharmacologic therapy for long QT syndrome and short QT syndrome.

The clinical significance of optimal pharmacotherapy for inherited arrhythmias such as short QT syndrome (SQTS) and long QT syndrome (LQTS) has been increasingly recognised. The advancement of gene technology has opened up new possibilities for identifying genetic variations and investigating the pathophysiological roles and mechanisms of genetic arrhythmias. Numerous variants in various genes have been proven to be causative in genetic arrhythmias. Studies have demonstrated that the effectiveness of certain drugs is specific to the patient or genotype, indicating the important role of gene-variants in drug response. This review aims to summarize the reported data on the impact of different gene-variants on drug response in SQTS and LQTS, as well as discuss the potential mechanisms by which gene-variants alter drug response. These findings may provide valuable information for future studies on the influence of gene variants on drug efficacy and the development of genotype-guided or precision treatment for these diseases.

Sex-specific cardiovascular remodeling leads to a divergent sex-dependent development of heart failure in aged hypertensive rats.

INTRODUCTION: The prevalence of heart failure with preserved ejection fraction (HFpEF) is continuously rising and predominantly affects older women often hypertensive and/or obese or diabetic. Indeed, there is evidence on sex differences in the development of HF. Hence, we studied cardiovascular performance dependent on sex and age as well as pathomechanisms on a cellular and molecular level. METHODS: We studied 15-week- and 1-year-old female and male hypertensive transgenic rats carrying the mouse Ren-2 renin gene (TG) and compared them to wild-type (WT) controls at the same age. We tracked blood pressure and cardiac function via echocardiography. After sacrificing the 1-year survivors we studied vascular smooth muscle and endothelial function. Isolated single skinned cardiomyocytes were used to determine passive stiffness and Ca2+-dependent force. In addition, Western blots were applied to analyse the phosphorylation status of sarcomeric regulatory proteins, titin and of protein kinases AMPK, PKG, CaMKII as well as their expression. Protein kinase activity assays were used to measure activities of CaMKII, PKG and angiotensin-converting enzyme (ACE). RESULTS: TG male rats showed significantly higher mortality at 1 year than females or WT male rats. Left ventricular (LV) ejection fraction was specifically reduced in male, but not in female TG rats, while LV diastolic dysfunction was evident in both TG sexes, but LV hypertrophy, increased LV ACE activity, and reduced AMPK activity as evident from AMPK hypophosphorylation were specific to male rats. Sex differences were also observed in vascular and cardiomyocyte function showing different response to acetylcholine and Ca2+-sensitivity of force production, respectively cardiomyocyte functional changes were associated with altered phosphorylation states of cardiac myosin binding protein C and cardiac troponin I phosphorylation in TG males only. Cardiomyocyte passive stiffness was increased in TG animals. On a molecular level titin phosphorylation pattern was altered, though alterations were sex-specific. Thus, also the reduction of PKG expression and activity was more pronounced in TG females. However, cardiomyocyte passive stiffness was restored by PKG and CaMKII treatments in both TG sexes. CONCLUSION: Here we demonstrated divergent sex-specific cardiovascular adaptation to the over-activation of the renin-angiotensin system in the rat. Higher mortality of male TG rats in contrast to female TG rats was observed as well as reduced LV systolic function, whereas females mainly developed HFpEF. Though both sexes developed increased myocardial stiffness to which an impaired titin function contributes to a sex-specific molecular mechanism. The functional derangements of titin are due to a sex-specific divergent regulation of PKG and CaMKII systems.

Protein Kinase D Plays a Crucial Role in Maintaining Cardiac Homeostasis by Regulating Post-Translational Modifications of Myofilament Proteins.

Protein kinase D (PKD) enzymes play important roles in regulating myocardial contraction, hypertrophy, and remodeling. One of the proteins phosphorylated by PKD is titin, which is involved in myofilament function. In this study, we aimed to investigate the role of PKD in cardiomyocyte function under conditions of oxidative stress. To do this, we used mice with a cardiomyocyte-specific knock-out of Prkd1, which encodes PKD1 (Prkd1loxP/loxP; αMHC-Cre; PKD1 cKO), as well as wild type littermate controls (Prkd1loxP/loxP; WT). We isolated permeabilized cardiomyocytes from PKD1 cKO mice and found that they exhibited increased passive stiffness (Fpassive), which was associated with increased oxidation of titin, but showed no change in titin ubiquitination. Additionally, the PKD1 cKO mice showed increased myofilament calcium (Ca2+) sensitivity (pCa50) and reduced maximum Ca2+-activated tension. These changes were accompanied by increased oxidation and reduced phosphorylation of the small myofilament protein cardiac myosin binding protein C (cMyBPC), as well as altered phosphorylation levels at different phosphosites in troponin I (TnI). The increased Fpassive and pCa50, and the reduced maximum Ca2+-activated tension were reversed when we treated the isolated permeabilized cardiomyocytes with reduced glutathione (GSH). This indicated that myofilament protein oxidation contributes to cardiomyocyte dysfunction. Furthermore, the PKD1 cKO mice exhibited increased oxidative stress and increased expression of pro-inflammatory markers interleukin (IL)-6, IL-18, and tumor necrosis factor alpha (TNF-α). Both oxidative stress and inflammation contributed to an increase in microtubule-associated protein 1 light chain 3 (LC3)-II levels and heat shock response by inhibiting the mammalian target of rapamycin (mTOR) in the PKD1 cKO mouse myocytes. These findings revealed a previously unknown role for PKD1 in regulating diastolic passive properties, myofilament Ca2+ sensitivity, and maximum Ca2+-activated tension under conditions of oxidative stress. Finally, we emphasized the importance of PKD1 in maintaining the balance of oxidative stress and inflammation in the context of autophagy, as well as cardiomyocyte function.

Takotsubo syndrome outcomes predicted by thyroid hormone signature: insights from cluster analysis of a multicentre registry.

BACKGROUND: Recently, abnormal thyroid function was shown to be common in patients with Takotsubo syndrome (TTS), being classified into "endocrine-type" and "stress-type" responses. The aim of this study was to investigate the association between thyroid homeostasis and TTS in a larger international registry. METHODS: In total 288 patients with TTS were enrolled through the GEIST multicentre registry from Germany, Italy and Spain. Thyrotropin (TSH), free T4 (FT4) and free T3 (FT3) concentrations were analysed at admission. Data were collected both retrospectively and prospectively from 2017 onwards. Primary endpoints included in-hospital and all-cause fatality, determined by cluster analysis using an unsupervised machine learning algorithm (k-medoids). FINDINGS: Three clusters were identified, classifying TTS with low (TSLT), high (TSHT) and normal (TSNT) thyroid output, based on TSH and FT4 levels in relation to the median thyroid's secretory capacity (SPINA-GT). Although TSH and FT4 concentrations were similar among survivors and non-survivors, these clusters were significantly associated with patient outcomes. In the longitudinal Kaplan-Meier analysis including in- and out-of-hospital survival, the prognosis related to concentrations of TSH, FT4, and FT3 as well as SPINA-GT, deiodinase activity (SPINA-GD) and clusters. Patients in the TSHT cluster and with cardiogenic shock had a lower initial left ventricular ejection fraction (LVEF). INTERPRETATION: This study suggests that thyroid hormones may impact the evolution and prognosis of TTS. The findings indicate that thyroid-derived biomarkers may help identify high-risk patients and pave the way for novel personalized and preventive therapeutic options. FUNDING: This research was not funded by any public, commercial, or not-for-profit agencies.

Reorganization of the actin cytoskeleton during the formation of neutrophil extracellular traps (NETs).

We analyzed actin cytoskeleton alterations during NET extrusion by neutrophil-like dHL-60 cells and human neutrophils in the absence of DNase1 containing serum to avoid chromatin degradation and microfilament disassembly. NET-formation by dHL-60 cells and neutrophils was induced by Ionomycin or phorbol-12-myristat-13-acetate (PMA). Subsequent staining with anti-actin and TRITC-phalloidin showed depolymerization of the cortical F-actin at spatially confined areas, the NET extrusion sites, effected by transient activation of the monooxygenase MICAL-1 supported by the G-actin binding proteins cofilin, profilin, thymosin ß4 and probably the F-actin fragmenting activity of gelsolin and/or its fragments, which also decorated the formed NETs. MICAL-1 itself appeared to be proteolyzed by neutrophil elastase possibly to confine its activity to the NET-extrusion area. The F-actin oxidization activity of MICAL-1 is inhibited by Levosimendan leading to reduced NET-formation. Anti-gasdermin-D immunohistochemistry showed a cytoplasmic distribution in non-stimulated cells. After stimulation the NET-extrusion pore displayed reduced anti-gasdermin-D staining but accumulated underneath the plasma membrane of the remaining cell body. A similar distribution was observed for myosin that concentrated together with cortical F-actin along the periphery of the remaining cell body suggesting force production by acto-myosin interactions supporting NET expulsion as indicated by the inhibitory action of the myosin ATPase inhibitor blebbistatin. Isolated human neutrophils displayed differences in their content of certain cytoskeletal proteins. After stimulation neutrophils with high gelsolin content preferentially formed "cloud"-like NETs, whereas those with low or no gelsolin formed long "filamentous" NETs.

The impact of diabetes mellitus on the outcome of troponin-positive patients with non-obstructive coronary arteries.

Background: Diabetes mellitus is a major cardiovascular risk factor for the development of coronary artery disease, but knowledge about the impact of diabetes mellitus on the outcome of patients with myocardial infarction with non-obstructive coronary arteries is limited. The aim of this study was to investigate the prognostic impact of diabetes mellitus on in- and out-of-hospital adverse events in troponin-positive patients with non-obstructive coronary arteries. Methods and Results: A total of 373 troponin-positive patients with non-obstructive coronary arteries between 2010 and 2021 at Bergmannsheil University Hospital Bochum were enrolled, including 65 diabetics and 307 nondiabetics. The median follow-up was 6.2 years. The primary study end point was a composite of in-hospital major adverse cardiovascular events (MACE). Secondary endpoints covered MACE during follow-up.Mean age of the study cohort was 62.9 years and 49.3 % were male. Although the overall rate of in-hospital MACE was higher in diabetics (41.5 %) than in non-diabetics (33.9 %), this difference did not reach statistical significance (p = 0.240). The in-hospital mortality rate was low in both groups, 0 % of diabetes group versus 2.9 % of non-diabetic patients. During follow-up, diabetic patients had a significantly higher rate of MACE (51.9 % vs. 31.1 %, p = 0.004) and a significantly higher all-cause mortality rate than non-diabetic patients (42.3 % vs. 20.1 %, p < 0.001). Conclusion: Our study reveals that the impact of diabetes mellitus on cardiovascular outcomes in troponin-positive patients with non-obstructive coronary arteries intensifies over the long term, leading to increased rates of both cardiovascular adverse events and overall mortality.