Functional reserve and contractile phenotype of atrial myocardium from patients with atrial remodeling without and with atrial fibrillation.

Atrial contractility and functional reserve in atrial remodeling (AR) without (AR/-AF) or with atrial fibrillation (AR/+AF) are not well characterized. In this study, functional measurements were performed in right atrial muscle strips (n = 71) obtained from patients (N = 22) undergoing routine cardiac surgery with either no AR [left atrial (LA) diameter < 40 mm and no history of AF (hAF)], AR/-AF (LA diameter ≥ 40 mm, no hAF), or AR/+AF (hAF and LA diameter ≥ 40 mm or LAEF < 45%). AR/-AF and AR/+AF were associated with a prolongation of half-time-to-peak (HTTP, P < 0.001) and time-to-peak (TTP) contraction (P < 0.01) when compared with no AR. This effect was seen at baseline and during ß-adrenergic stimulation with isoproterenol (Iso). Early relaxation assessed by half-relaxation time (HRT) was prolonged in AR/-AF (P = 0.03) but not in AR/+AF when compared with no AR at baseline, but this delay in relaxation in AR/-AF was attenuated with Iso. Late relaxation (τ) did not differ between AR/-AF and no AR but was consistently shorter in AR/+AF than no AR before (P = 0.04) and during Iso (P = 0.01), indicating accelerated late relaxation in AR/+AF. Relative force increase during Iso was higher (P = 0.01) and more dispersed (P = 0.047) in patients with AR/+AF. Relative adrenergic response was unaltered in the myocardium of patients with AR/-AF and AR/+AF. In conclusion, AR/-AF and AR/+AF are associated with changes in myocardial inotropic reserve and contractility. The changes are particularly pronounced in patients with AR/+AF, suggesting that the progression from AR/-AF to AR/+AF is associated with progressive alterations in atrial function that may contribute to arrhythmogenesis.NEW & NOTEWORTHY Mechanical alterations in atrial remodeling without (AR/-AF) and with atrial fibrillation (AR/+AF) have not been studied in detail in human atrial tissue preparations. To our knowledge, this is the first study to compare the mechanical phenotype and inotropic reserve in human atrial myocardial preparations from patients with no atrial remodeling, AR/-AF, and AR/+AF. We identify specific patterns of contractile dysfunction and heterogeneity for both, AR/-AF and AR/+AF, indicating the progression of atrial disease.

Dual SGLT-1 and SGLT-2 inhibition improves left atrial dysfunction in HFpEF.

BACKGROUND: Sodium-glucose linked transporter type 2 (SGLT-2) inhibition has been shown to reduce cardiovascular mortality in heart failure independently of glycemic control and prevents the onset of atrial arrhythmias, a common co-morbidity in heart failure with preserved ejection fraction (HFpEF). The mechanism behind these effects is not fully understood, and it remains unclear if they could be further enhanced by additional SGLT-1 inhibition. We investigated the effects of chronic treatment with the dual SGLT-1&2 inhibitor sotagliflozin on left atrial (LA) remodeling and cellular arrhythmogenesis (i.e. atrial cardiomyopathy) in a metabolic syndrome-related rat model of HFpEF. METHODS: 17 week-old ZSF-1 obese rats, a metabolic syndrome-related model of HFpEF, and wild type rats (Wistar Kyoto), were fed 30 mg/kg/d sotagliflozin for 6 weeks. At 23 weeks, LA were imaged in-vivo by echocardiography. In-vitro, Ca2+ transients (CaT; electrically stimulated, caffeine-induced) and spontaneous Ca2+ release were recorded by ratiometric microscopy using Ca2+-sensitive fluorescent dyes (Fura-2) during various experimental protocols. Mitochondrial structure (dye: Mitotracker), Ca2+ buffer capacity (dye: Rhod-2), mitochondrial depolarization (dye: TMRE) and production of reactive oxygen species (dye: H2DCF) were visualized by confocal microscopy. Statistical analysis was performed with 2-way analysis of variance followed by post-hoc Bonferroni and student's t-test, as applicable. RESULTS: Sotagliflozin ameliorated LA enlargement in HFpEF in-vivo. In-vitro, LA cardiomyocytes in HFpEF showed an increased incidence and amplitude of arrhythmic spontaneous Ca2+ release events (SCaEs). Sotagliflozin significantly reduced the magnitude of SCaEs, while their frequency was unaffected. Sotagliflozin lowered diastolic [Ca2+] of CaT at baseline and in response to glucose influx, possibly related to a ~ 50% increase of sodium sodium-calcium exchanger (NCX) forward-mode activity. Sotagliflozin prevented mitochondrial swelling and enhanced mitochondrial Ca2+ buffer capacity in HFpEF. Sotagliflozin improved mitochondrial fission and reactive oxygen species (ROS) production during glucose starvation and averted Ca2+ accumulation upon glycolytic inhibition. CONCLUSION: The SGLT-1&2 inhibitor sotagliflozin ameliorated LA remodeling in metabolic HFpEF. It also improved distinct features of Ca2+-mediated cellular arrhythmogenesis in-vitro (i.e. magnitude of SCaEs, mitochondrial Ca2+ buffer capacity, diastolic Ca2+ accumulation, NCX activity). The safety and efficacy of combined SGLT-1&2 inhibition for the treatment and/or prevention of atrial cardiomyopathy associated arrhythmias should be further evaluated in clinical trials.

The role of fibroblast - Cardiomyocyte interaction for atrial dysfunction in HFpEF and hypertensive heart disease.

AIMS: Atrial contractile dysfunction is associated with increased mortality in heart failure (HF). We have shown previously that a metabolic syndrome-based model of HFpEF and a model of hypertensive heart disease (HHD) have impaired left atrial (LA) function in vivo (rat). In this study we postulate, that left atrial cardiomyocyte (CM) and cardiac fibroblast (CF) paracrine interaction related to the inositol 1,4,5-trisphosphate signalling cascade is pivotal for the manifestation of atrial mechanical dysfunction in HF and that quantitative atrial remodeling is highly disease-dependent. METHODS AND RESULTS: Differential remodeling was observed in HHD and HFpEF as indicated by an increase of atrial size in vivo (HFpEF), unchanged fibrosis (HHD and HFpEF) and a decrease of CM size (HHD). Baseline contractile performance of rat CM in vitro was enhanced in HFpEF. Upon treatment with conditioned medium from their respective stretched CF (CM-SF), CM (at 21 weeks) of WT showed increased Ca2+ transient (CaT) amplitudes related to the paracrine activity of the inotrope endothelin (ET-1) and inositol 1,4,5-trisphosphate induced Ca2+ release. Concentration of ET-1 was increased in CM-SF and atrial tissue from WT as compared to HHD and HFpEF. In HHD, CM-SF had no relevant effect on CaT kinetics. However, in HFpEF, CM-SF increased diastolic Ca2+ and slowed Ca2+ removal, potentially contributing to an in-vivo decompensation. During disease progression (i.e. at 27 weeks), HFpEF displayed dysfunctional excitation-contraction-coupling (ECC) due to lower sarcoplasmic-reticulum Ca2+ content unrelated to CF-CM interaction or ET-1, but associated with enhanced nuclear [Ca2+]. In human patients, tissue ET-1 was not related to the presence of arterial hypertension or obesity. CONCLUSIONS: Atrial remodeling is a complex entity that is highly disease and stage dependent. The activity of fibrosis related to paracrine interaction (e.g. ET-1) might contribute to in vitro and in vivo atrial dysfunction. However, during later stages of disease, ECC is impaired unrelated to CF.

Cellular mechanisms of metabolic syndrome-related atrial decompensation in a rat model of HFpEF.

Heart failure (HF) with preserved ejection fraction (HFpEF) is present in about 50% of HF patients. Atrial remodeling is common in HFpEF and associated with increased mortality. We postulate that atrial remodeling is associated with atrial dysfunction in vivo related to alterations in cardiomyocyte Calcium (Ca) signaling and remodeling. We examined atrial function in vivo and Ca transients (CaT) (Fluo4-AM, field stim) in atrial cardiomyocytes of ZSF-1 rats without (Ln; lean hypertensive) and with metabolic syndrome (Ob; obese, hypertensive, diabetic) and HFpEF. RESULTS: At 21weeks Ln showed an increased left ventricular (LV) mass and left ventricular end-diastolic pressure (LVEDP), but unchanged left atrial (LA) size and preserved atrial ejection fraction vs. wild-type (WT). CaT amplitude in atrial cardiomyocytes was increased in Ln (2.9±0.2 vs. 2.3±0.2F/F0 in WT; n=22 cells/group; p<0.05). Studying subcellular Ca release in more detail, we found that local central cytosolic CaT amplitude was increased, while subsarcolemmal CaT amplitudes remained unchanged. Moreover, Sarcoplasmic reticulum (SR) Ca content (caffeine) was preserved while Ca spark frequency and tetracaine-dependent SR Ca leak were significantly increased in Ln. Ob mice developed a HFpEF phenotype in vivo, LA area was significantly increased and atrial in vivo function was impaired, despite increased atrial CaT amplitudes in vitro (2.8±0.2; p<0.05 vs. WT). Ob cells showed alterations of the tubular network possibly contributing to the observed phenotype. CaT kinetics as well as SR Ca in Ob were not significantly different from WT, but SR Ca leak remained increased. Angiotensin II (Ang II) reduced in vitro cytosolic CaT amplitudes and let to active nuclear Ca release in Ob but not in Ln or WT. SUMMARY: In hypertensive ZSF-1 rats, a possibly compensatory increase of cytosolic CaT amplitude and increased SR Ca leak precede atrial remodeling and HFpEF. Atrial remodeling in ZSF-1 HFpEF is associated with an altered tubular network in-vitro and atrial contractile dysfunction in vivo, indicating insufficient compensation. Atrial cardiomyocyte dysfunction in vitro is induced by the addition of angiotensin II.

Shockwaves prevent from heart failure after acute myocardial ischaemia via RNA/protein complexes.

Shock wave treatment (SWT) was shown to induce regeneration of ischaemic myocardium via Toll-like receptor 3 (TLR3). The antimicrobial peptide LL37 gets released by mechanical stress and is known to form complexes with nucleic acids thus activating Toll-like receptors. We suggested that SWT in the acute setting prevents from the development of heart failure via RNA/protein release. Myocardial infarction in mice was induced followed by subsequent SWT. Heart function was assessed 4 weeks later via transthoracic echocardiography and pressure-volume measurements. Human umbilical vein endothelial cells (HUVECs) were treated with SWT in the presence of RNase and proteinase and analysed for proliferation, tube formation and LL37 expression. RNA release and uptake after SWT was evaluated. We found significantly improved cardiac function after SWT. SWT resulted in significantly higher numbers of capillaries and arterioles and less left ventricular fibrosis. Supernatants of treated cells activated TLR3 reporter cells. Analysis of the supernatant revealed increased RNA levels. The effect could not be abolished by pre-treatment of the supernatant with RNase, but only by a sequential digestion with proteinase and RNase hinting strongly towards the involvement of RNA/protein complexes. Indeed, LL37 expression as well as cellular RNA uptake were significantly increased after SWT. We show for the first time that SWT prevents from left ventricular remodelling and cardiac dysfunction via RNA/protein complex release and subsequent induction of angiogenesis. It might therefore develop a potent regenerative treatment alternative for ischaemic heart disease.

AMP-activated protein kinase α1-sensitive activation of AP-1 in cardiomyocytes.

AMP-activated protein kinase (Ampk) regulates myocardial energy metabolism and plays a crucial role in the response to cell stress. In the failing heart, an isoform shift of the predominant Ampkα2 to the Ampkα1 was observed. The present study explored possible isoform specific effects of Ampkα1 in cardiomyocytes. To this end, experiments were performed in HL-1 cardiomyocytes, as well as in Ampkα1-deficient and corresponding wild-type mice and mice following AAV9-mediated cardiac overexpression of constitutively active Ampkα1. As a result, in HL-1 cardiomyocytes, overexpression of constitutively active Ampkα1 increased the phosphorylation of Pkcζ. Constitutively active Ampkα1 further increased AP-1-dependent transcriptional activity and mRNA expression of the AP-1 target genes c-Fos, Il6 and Ncx1, effects blunted by Pkcζ silencing. In HL-1 cardiomyocytes, angiotensin-II activated AP-1, an effect blunted by silencing of Ampkα1 and Pkcζ, but not of Ampkα2. In wild-type mice, angiotensin-II infusion increased cardiac Ampkα1 and cardiac Pkcζ protein levels, as well as c-Fos, Il6 and Ncx1 mRNA expression, effects blunted in Ampkα1-deficient mice. Pressure overload by transverse aortic constriction (TAC) similarly increased cardiac Ampkα1 and Pkcζ abundance as well as c-Fos, Il6 and Ncx1 mRNA expression, effects again blunted in Ampkα1-deficient mice. AAV9-mediated cardiac overexpression of constitutively active Ampkα1 increased Pkcζ protein abundance and the mRNA expression of c-Fos, Il6 and Ncx1 in cardiac tissue. In conclusion, Ampkα1 promotes myocardial AP-1 activation in a Pkcζ-dependent manner and thus contributes to cardiac stress signaling.

AMP-activated protein kinase α1 regulates cardiac gap junction protein connexin 43 and electrical remodeling following pressure overload.

BACKGROUND/AIMS: Adenosine 5'-monophosphate (AMP)-activated protein kinase (Ampk) modulates a wide array of cellular functions and regulates various ion channels and transporters. In failing human hearts an increased Ampkα1 activity was observed. The present study aimed to uncover the impact of Ampkα1 on cardiac electrical remodeling. METHODS: Gene-targeted mice lacking functional Ampkα1 (Ampkα1-/-) and corresponding wild-type mice were exposed to pressure overload by "transverse aortic constriction" (TAC). In vivo electrophysiology was performed with a single catheter technique, myocardial conduction velocities and conduction characteristics investigated in isolated hearts, transcript levels quantified by RT-PCR and protein abundance determined by Western blotting. Moreover, connexin 43 (Cx43) was expressed in Xenopus oocytes with or without coexpression of wild-type or mutant AMPK and Cx43 protein abundance quantified utilizing confocal microscopy. RESULTS: TAC treatment increased Ampkα1 protein expression in cardiac tissue from wild-type mice. TAC further increased left ventricular conduction inhomogeneity and triggered conduction blocks, effects blunted in the Ampkα1(-/-) mice. TAC treatment decreased Cx43 protein abundance in cardiac tissue, an effect significantly blunted in the Ampkα1(-/-) mice. TAC treatment did not modify Cx43 mRNA levels but increased ubiquitination of Cx43 protein, an effect mitigated by Ampkα1 deficiency. As shown in Xenopus oocytes, Cx43 cell membrane protein abundance was significantly downregulated by wild-type AMPK(WT) and constitutively active AMPK(γR70Q), but not by catalytically inactive AMPK(αK45R). CONCLUSION: Ampkα1 stimulates ubiquitination of the gap junction protein Cx43, thereby contributing to gap junction remodeling following pressure overload.

Clinical outcome and intraprocedural characteristics of left atrial appendage occlusion: a comparison between single-occlusive plug-type and dual-occlusive disc-type devices.

Background: Percutaneous interventional left atrial appendage occlusion (LAAO) is a reliable, safe, and effective alternative for stroke prevention in selected patients with atrial fibrillation (AF). Methods: In a retrospective observational study, 149 patients underwent LAAO between 2016 and 2022 at the Department of Cardiology of the Charité-Universitätsmedizin Berlin, Campus Virchow, with AF for prevention of thromboembolic complications. We compared patient characteristics, intraoperative details and postoperative outcomes between single-occlusive plug-type (SOPT) and dual-occlusive disc-type (DODT) devices. Results: In all patients, the device implantation was successful. 60 patients received a SOPT occluder, including Watchman (35%) and Watchman FLX Occluders (65%), while 89 patients received a DODT occluder, including Amplatzer Cardiac Plug (37.1%), the Amplatzer Amulet (25.8%), and the LAmbre occluder (37.1%) systems. Procedure duration was significantly longer for DODT occluder implantation (49 ± 33 vs. 41 ± 25 min, p = 0.018). There were no in-hospital deaths or thromboembolic events reported after LAAO in both groups. Beyond that, a low rate of bleeding or access-side-related complications and pericardial tamponades were observed. Anticoagulation at discharge varied. About 60.8% of patients received dual antiplatelet therapy at hospital discharge, and 33.1% received direct oral anticoagulants. A 6-month follow-up was obtained in 85% of the patients. All implanted devices were in the desired position. However, in 5.7% of the patients, a device-related thrombus formation was detected in the SOPT group, while no thrombus was seen in the DODT group (p = 0.11). Thromboembolic events were noticed in 3.1%, without any difference between the device types. There was a statistically non-significant trend for less residual device leaks after SOPT vs. DODT implantation (no leak in 71.7% vs. 62.2%, p = 0.07; minor leaks <5 mm, 9.4% vs. 20.3%, p = 0.1). In the SOPT group, less bleeding complications were reported after LAAO (11.3% vs. 17.6%, p = 0.1). Conclusion: Our data suggest the safety and efficiency of LAAO with a very high procedural implantation success rate irrespective of the used LAA device. Furthermore, no relevant procedural or device-related complication occurred during the 6-month follow-up in all patients.

Occlusion of functional high-volume intra-atrial shunts in older patients after embolic stroke of undetermined source.

Background: Intra-atrial shunts are associated with an elevated risk of embolic stroke of undetermined source (ESUS). Percutaneous occluder implantation is recommended as secondary prevention in younger patients. This study aims to compare the outcome after shunt occlusion between younger and older patients with a history of presumed paradox embolism and to evaluate the impact of high-volume shunting in an elderly population. Methods: We conducted a single-center, retrospective, observational study, involving 187 patients who underwent interventional percutaneous PFO or ASD occlusion at our center between 2013 and 2023. Results: The mean age of participants was 51.8 ± 11.8 years, with 76 patients aged ≤50 years and 111 patients aged >50 years. Older patients presented more cardiovascular risk factors. The presence of atrial septum aneurysm or large shunting was evenly distributed (ASA 26.3% vs. 28.8%, p = 0.833, mean shunt defect size 6.67 vs. 7.23 mm, p = 0.151). There were no significant differences in procedural or intrahospital complications. The event rate during the 6-month follow-up was low. Recurrence of arterial embolism occurred in 1.6% of the younger and 3.8% of the older patients (p = 0.817). Comparison of high-volume shunts (defect size ≥10 mm or passage ≥20 bubbles during bubble study) with low-volume shunts in this elderly cohort with a mean age ≥50 years showed no significant difference in outcomes. There was a statistically non-significant trend toward a higher rate of residual shunt at the end of the procedure in the high-volume shunt group (2.9% vs. 9.8%, p = 0.0894). This difference was not observed at the 6-month follow-up anymore (14.5 vs. 12.1%, p = 0.628). Two unsuccessful implantation attempts were reported in the high-volume shunt group, while none were observed in the low-volume shunt group (p = 0.372). No intervention-related deaths occurred in this patient cohort during follow-up. Conclusion: Occlusion of relevant, intra-atrial shunting is a safe and effective option for secondary prevention of cryptogenic embolism in patients over 50 years of age. The beneficial outcome was irrespective of a high-volume shunting before implantation.

Early clinical outcomes of Portico and Edwards Sapien 3 valve prosthesis in transcatheter aortic valve replacement: propensity-matched analysis.

Introduction: There is a lack of real-world data directly comparing different valve prostheses for transaortic valve replacement (TAVR). We aimed to compare early clinical outcomes at 30-days between the self-expandable Portico valve (Abbott) with the balloon-expandable Edwards Sapien 3 valve (Edwards Lifesciences) (ES3). Methods: Out of 1,901 patients undergoing TAVR between January 2018 and December 2021, all patients who received either Portico valve or ES3 valve via transfemoral TAVR were matched using nearest-neighbor (1:1) propensity scoring. Primary endpoints were single safety endpoints and early safety composite endpoints defined by Valve Academic Research Consortium-2 (VARC-2) criteria. The secondary endpoint was to analyze risk predictors for new permanent pacemaker (PPM) implantation in TAVR. Results: Out of 661 complete cases, a total of 434 patients were successfully matched based on age, sex, Euro Score II and STS-score. In the matched cohort, 217 received either a Portico or valve and 217 received an ES3 valve. The VARC-2 early safety composite scores indicated a significantly greater overall 30-day safety risk in the Portico group at 9.2% (n = 20) compared to 3.7% (n = 8) in the ES3 group (p = 0.032). The requirement for new permanent pacemaker (PPM) implantation was also higher in the Portico group, at 21.2% (n = 46) vs. 13.4% (n = 29) in the ES3 group (p = 0.042). 30-day mortality was higher was 3.7% (n = 8) in Portico group compared to 0.9% in ES3 group (p = 0.11). Furthermore, implantation of the Portico valve was identified as a significant risk predictor for new PPM implantation, alongside higher age, preprocedural atrioventricular block (AVB) and longer total procedure duration. Conclusion: This study shows significantly higher rates of early clinical complications for Portico valve prostheses compared to ES3. These findings should be especially taken into consideration when selecting valve prosthesis for high-risk patients.

Lung-to-Heart Nano-in-Micro Peptide Promotes Cardiac Recovery in a Pig Model of Chronic Heart Failure.

BACKGROUND: The lack of disease-modifying drugs is one of the major unmet needs in patients with heart failure (HF). Peptides are highly selective molecules with the potential to act directly on cardiomyocytes. However, a strategy for effective delivery of therapeutics to the heart is lacking. OBJECTIVES: In this study, the authors sought to assess tolerability and efficacy of an inhalable lung-to-heart nano-in-micro technology (LungToHeartNIM) for cardiac-specific targeting of a mimetic peptide (MP), a first-in-class for modulating impaired L-type calcium channel (LTCC) trafficking, in a clinically relevant porcine model of HF. METHODS: Heart failure with reduced ejection fraction (HFrEF) was induced in Göttingen minipigs by means of tachypacing over 6 weeks. In a setting of overt HFrEF (left ventricular ejection fraction [LVEF] 30% ± 8%), animals were randomized and treatment was started after 4 weeks of tachypacing. HFrEF animals inhaled either a dry powder composed of mannitol-based microparticles embedding biocompatible MP-loaded calcium phosphate nanoparticles (dpCaP-MP) or the LungToHeartNIM only (dpCaP without MP). Efficacy was evaluated with the use of echocardiography, invasive hemodynamics, and biomarker assessment. RESULTS: DpCaP-MP inhalation restored systolic function, as shown by an absolute LVEF increase over the treatment period of 17% ± 6%, while reversing cardiac remodeling and reducing pulmonary congestion. The effect was recapitulated ex vivo in cardiac myofibrils from treated HF animals. The treatment was well tolerated, and no adverse events occurred. CONCLUSIONS: The overall tolerability of LungToHeartNIM along with the beneficial effects of the LTCC modulator point toward a game-changing treatment for HFrEF patients, also demonstrating the effective delivery of a therapeutic peptide to the diseased heart.

Effects of BNP and Sacubitrilat/Valsartan on Atrial Functional Reserve and Arrhythmogenesis in Human Myocardium.

Background: Although the angiotensin receptor-neprilysin inhibitor (ARNI) sacubitril/valsartan started a new era in heart failure (HF) treatment, less is known about the tissue-level effects of the drug on the atrial myocardial functional reserve and arrhythmogenesis. Methods and Results: Right atrial (RA) biopsies were retrieved from patients (n = 42) undergoing open-heart surgery, and functional experiments were conducted in muscle strips (n = 101). B-type natriuretic peptide (BNP) did not modulate systolic developed force in human myocardium during ß-adrenergic stimulation, but it significantly reduced diastolic tension (p < 0.01) and the probability of arrhythmias (p < 0.01). In addition, patient's plasma NTproBNP positively correlated with isoproterenol-induced contractile reserve in atrial tissue in vitro (r = 0.65; p < 0.01). Sacubitrilat+valsartan (Sac/Val) did not show positive inotropic effects on atrial trabeculae function but reduced arrhythmogeneity. Atrial and ventricular biopsies from patients with end-stage HF (n = 10) confirmed that neprilysin (NEP) is equally expressed in human atrial and ventricular myocardium. RA NEP expression correlates positively with RA ejection fraction (EF) (r = 0.806; p < 0.05) and left ventricle (LV) NEP correlates inversely with left atrial (LA) volume (r = -0.691; p < 0.05). Conclusion: BNP ameliorates diastolic tension during adrenergic stress in human atrial myocardium and may have positive long-term effects on the inotropic reserve. BNP and Sac/Val reduce atrial arrhythmogeneity during adrenergic stress in vitro. Myocardial NEP expression is downregulated with declining myocardial function, suggesting a compensatory mechanism in HF.

Cpxm2 as a novel candidate for cardiac hypertrophy and failure in hypertension.

Treatment of hypertension-mediated cardiac damage with left ventricular (LV) hypertrophy (LVH) and heart failure remains challenging. To identify novel targets, we performed comparative transcriptome analysis between genetic models derived from stroke-prone spontaneously hypertensive rats (SHRSP). Here, we identified carboxypeptidase X 2 (Cpxm2) as a genetic locus affecting LV mass. Analysis of isolated rat cardiomyocytes and cardiofibroblasts indicated Cpxm2 expression and intrinsic upregulation in genetic hypertension. Immunostaining indicated that CPXM2 associates with the t-tubule network of cardiomyocytes. The functional role of Cpxm2 was further investigated in Cpxm2-deficient (KO) and wild-type (WT) mice exposed to deoxycorticosterone acetate (DOCA). WT and KO animals developed severe and similar systolic hypertension in response to DOCA. WT mice developed severe LV damage, including increases in LV masses and diameters, impairment of LV systolic and diastolic function and reduced ejection fraction. These changes were significantly ameliorated or even normalized (i.e., ejection fraction) in KO-DOCA animals. LV transcriptome analysis showed a molecular cardiac hypertrophy/remodeling signature in WT but not KO mice with significant upregulation of 1234 transcripts, including Cpxm2, in response to DOCA. Analysis of endomyocardial biopsies from patients with cardiac hypertrophy indicated significant upregulation of CPXM2 expression. These data support further translational investigation of CPXM2.

Increased mortality and worse cardiac outcome of acute myocardial infarction during the early COVID-19 pandemic.

AIMS: This study aimed to evaluate the impact of coronavirus disease 2019 (Covid-19) outbreak on admissions for acute myocardial infarction (AMI) and related mortality, severity of presentation, major cardiac complications and outcome in a tertiary-care university hospital in Berlin, Germany. METHODS AND RESULTS: In a single-centre cross-sectional observational study, we included 355 patients with AMI containing ST-elevation or non-ST-elevation myocardial infarction (STEMI or NSTEMI), admitted for emergency cardiac catheterization between January and April 2020 and the equivalent time in 2019. During the early phase of the Covid-19 pandemic (e-COV) in Berlin (March and April 2020), admissions for AMI halved compared with those in the pre-Covid-19 time (January and February 2020; pre-COV) and with those in the corresponding months in 2019. However, mortality for AMI increased substantially from 5.2% pre-COV to 17.7% (P < 0.05) during e-COV. Severity of presentation for AMI was more pronounced during e-COV [increased levels of cardiac enzymes, reduced left ventricular ejection fraction (LVEF), an increase in the need of inotropic support by 25% (P < 0.01)], while patients' demographic and angiographic characteristics did not differ between pre-COV and e-COV. Time from symptom onset to first medical contact was prolonged in all AMI during e-COV (presentation > 72 h +21% in STEMI, p = 0.04 and presentation > 72 h in NSTEMI +22%, p = 0.02). Door to balloon time was similar in STEMI patients, while time from first medical contact to revascularization was significantly delayed in NSTEMI patients (p = 0.02). Major cardiac complications after AMI occurred significantly more often, and cardiac recovery was worse in e-COV than in pre-COV, demonstrated by a significantly lower LVEF (39 ± 16 vs. 46 ± 16, p < 0.05) at hospital discharge and substantially higher NTproBNP levels. CONCLUSIONS: The Covid-19 outbreak affects hospital admissions for acute coronary syndromes. During the first phase of the pandemia, significantly less patients with AMI were admitted, but those admitted presented with a more severe phenotype and had a higher mortality, more complications, and a worse short-term outcome. Therefore, our data indicate that Covid-19 had relevant impact on non-infectious disease states, such as acute coronary syndromes.

Effects of different exercise modalities on cardiac dysfunction in heart failure with preserved ejection fraction.

AIMS: Heart failure with preserved ejection fraction (HFpEF) is an increasingly prevalent disease. Physical exercise has been shown to alter disease progression in HFpEF. We examined cardiomyocyte Ca2+ homeostasis and left ventricular function in a metabolic HFpEF model in sedentary and trained rats following 8 weeks of moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT). METHODS AND RESULTS: Left ventricular in vivo function (echocardiography) and cardiomyocyte Ca2+ transients (CaTs) (Fluo-4, confocal) were compared in ZSF-1 obese (metabolic syndrome, HFpEF) and ZSF-1 lean (control) 21- and 28-week-old rats. At 21 weeks, cardiomyocytes from HFpEF rats showed prolonged Ca2+ reuptake in cytosolic and nuclear CaTs and impaired Ca2+ release kinetics in nuclear CaTs. At 28 weeks, HFpEF cardiomyocytes had depressed CaT amplitudes, decreased sarcoplasmic reticulum (SR) Ca2+ content, increased SR Ca2+ leak, and elevated diastolic [Ca2+ ] following increased pacing rate (5 Hz). In trained HFpEF rats (HIIT or MICT), cardiomyocyte SR Ca2+ leak was significantly reduced. While HIIT had no effects on the CaTs (1-5 Hz), MICT accelerated early Ca2+ release, reduced the amplitude, and prolonged the CaT without increasing diastolic [Ca2+ ] or cytosolic Ca2+ load at basal or increased pacing rate (1-5 Hz). MICT lowered pro-arrhythmogenic Ca2+ sparks and attenuated Ca2+ -wave propagation in cardiomyocytes. MICT was associated with increased stroke volume in HFpEF. CONCLUSIONS: In this metabolic rat model of HFpEF at an advanced stage, Ca2+ release was impaired under baseline conditions. HIIT and MICT differentially affected Ca2+ homeostasis with positive effects of MICT on stroke volume, end-diastolic volume, and cellular arrhythmogenicity.

Right-ventricular dysfunction in HFpEF is linked to altered cardiomyocyte Ca2+ homeostasis and myofilament sensitivity.

AIMS: Heart failure with preserved ejection fraction (HFpEF) is frequently (30%) associated with right ventricular (RV) dysfunction, which increases morbidity and mortality in these patients. Yet cellular mechanisms of RV remodelling and RV dysfunction in HFpEF are not well understood. Here, we evaluated RV cardiomyocyte function in a rat model of metabolically induced HFpEF. METHODS AND RESULTS: Heart failure with preserved ejection fraction-prone animals (ZSF-1 obese) and control rats (Wistar Kyoto) were fed a high-caloric diet for 13 weeks. Haemodynamic characterization by echocardiography and invasive catheterization was performed at 22 and 23 weeks of age, respectively. After sacrifice, organ morphometry, RV histology, isolated RV cardiomyocyte function, and calcium (Ca2+ ) transients were assessed. ZSF-1 obese rats showed a HFpEF phenotype with left ventricular (LV) hypertrophy, LV diastolic dysfunction (including increased LV end-diastolic pressures and E/e' ratio), and preserved LV ejection fraction. ZSF-1 obese animals developed RV dilatation (50% increased end-diastolic area) and mildly impaired RV ejection fraction (42%) with evidence of RV hypertrophy. In isolated RV cardiomyocytes from ZSF-1 obese rats, cell shortening amplitude was preserved, but cytosolic Ca2+ transient amplitude was reduced. In addition, augmentation of cytosolic Ca2+ release with increased stimulation frequency was lost in ZSF-1 obese rats. Myofilament sensitivity was increased, while contractile kinetics were largely unaffected in intact isolated RV cardiomyocytes from ZSF-1 obese rats. Western blot analysis revealed significantly increased phosphorylation of cardiac myosin-binding protein C (Ser282 cMyBP-C) but no change in phosphorylation of troponin I (Ser23, 24 TnI) in RV myocardium from ZSF-1 obese rats. CONCLUSIONS: Right ventricular dysfunction in obese ZSF-1 rats with HFpEF is associated with intrinsic RV cardiomyocyte remodelling including reduced cytosolic Ca2+ amplitudes, loss of frequency-dependent augmentation of Ca2+ release, and increased myofilament Ca2+ sensitivity.

Impaired Relaxation and Reduced Lusitropic Reserve in Atrial Myocardium in the Obese Patients.

Background: Obesity can influence the structure and function of the atrium, but most studies focused on the relationship of body mass index (BMI) and overt left atrium (LA) dysfunction as assessed by clinical imaging. We combined the assessment of right atrium (RA) function in vivo and in vitro in obese and non-obese patients scheduled for elective cardiac surgery. Methods: Atrial structure and function were quantified pre-operatively by echocardiography. RA tissue removed for the establishment of extracorporeal support was collected and RA trabeculae function was quantified in vitro at baseline and with adrenergic stimulation (isoproterenol). Fatty acid-binding protein 3 (FABP3) was quantified in RA tissue. Results were stratified according to the BMI of the patients. Results: About 76 patients were included pre-operatively for the echocardiographic analysis. RA trabeculae function at baseline was finally quantified from 46 patients and RA function in 28 patients was also assessed with isoproterenol. There was no significant correlation between BMI and the parameters of atrial function measured by the clinical echocardiography. However, in vitro measurements revealed a significant correlation between BMI and a prolonged relaxation of the atrial myocardium at baseline, which persisted after controlling for the atrial fibrillation and diabetes by the partial correlation analysis. Acceleration of relaxation with isoproterenol was significantly lower in the obese group (BMI ≥ 30 kg/m2). As a result, relaxation with adrenergic stimulation in the obese group remained significantly higher compared to the overweight group (25 kg/m2 ≤ BMI < 30 kg/m2, p = 0.027) and normal group (18.5 kg/m2 ≤ BMI < 25 kg/m2, p = 0.036). There were no differences on impacts of the isoproterenol on (systolic) developed force between groups. The expression of FABP3 in the obese group was significantly higher compared to the normal group (p = 0.049) and the correlation analysis showed the significant correlations between the level of FABP3 in the RA trabeculae function. Conclusion: A higher BMI is associated with the early subclinical changes of RA myocardial function with the slowed relaxation and reduced adrenergic lusitropy.

Oxidative Stress and Inflammatory Modulation of Ca2+ Handling in Metabolic HFpEF-Related Left Atrial Cardiomyopathy.

Metabolic syndrome-mediated heart failure with preserved ejection fraction (HFpEF) is commonly accompanied by left atrial (LA) cardiomyopathy, significantly affecting morbidity and mortality. We evaluate the role of reactive oxygen species (ROS) and intrinsic inflammation (TNF-α, IL-10) related to dysfunctional Ca2+ homeostasis of LA cardiomyocytes in a rat model of metabolic HFpEF. ZFS-1 obese rats showed features of HFpEF and atrial cardiomyopathy in vivo: increased left ventricular (LV) mass, E/e' and LA size and preserved LV ejection fraction. In vitro, LA cardiomyocytes exhibited more mitochondrial-fission (MitoTracker) and ROS-production (H2DCF). In wildtype (WT), pro-inflammatory TNF-α impaired cellular Ca2+ homeostasis, while anti-inflammatory IL-10 had no notable effect (confocal microscopy; Fluo-4). In HFpEF, TNF-α had no effect on Ca2+ homeostasis associated with decreased TNF-α receptor expression (western blot). In addition, IL-10 substantially improved Ca2+ release and reuptake, while IL-10 receptor-1 expression was unaltered. Oxidative stress in metabolic syndrome mediated LA cardiomyopathy was increased and anti-inflammatory treatment positively affected dysfunctional Ca2+ homeostasis. Our data indicates, that patients with HFpEF-related LA dysfunction might profit from IL-10 targeted therapy, which should be further explored in preclinical trials.

Left ventricular dysfunction in heart failure with preserved ejection fraction-molecular mechanisms and impact on right ventricular function.

The current classification of heart failure (HF) based on left ventricular (LV) ejection fraction (EF) identifies a large group of patients with preserved ejection fraction (HFpEF) with significant morbidity and mortality but without prognostic benefit from current HF therapy. Co-morbidities and conditions such as arterial hypertension, diabetes mellitus, chronic kidney disease, adiposity and aging shape the clinical phenotype and contribute to mortality. LV diastolic dysfunction and LV structural remodeling are hallmarks of HFpEF, and are linked to remodeling of the cardiomyocyte and extracellular matrix. Pulmonary hypertension (PH) and right ventricular dysfunction (RVD) are particularly common in HFpEF, and mortality is up to 10-fold higher in HFpEF patients with vs. without RV dysfunction. Here, we review alterations in cardiomyocyte function (i.e., ion homeostasis, sarcomere function and cellular metabolism) associated with diastolic dysfunction and summarize the main underlying cellular pathways. The contribution and interaction of systemic and regional upstream signaling such as chronic inflammation, neurohumoral activation, and NO-cGMP-related pathways are outlined in detail, and their diagnostic and therapeutic potential is discussed in the context of preclinical and clinical studies. In addition, we summarize prevalence and pathomechanisms of RV dysfunction in the context of HFpEF and discuss mechanisms connecting LV and RV dysfunction in HFpEF. Dissecting the molecular mechanisms of LV and RV dysfunction in HFpEF may provide a basis for an improved classification of HFpEF and for therapeutic approaches tailored to the molecular phenotype.

Long-term effects of a food pattern on cardiovascular risk factors and age-related changes of muscular and cognitive function.

INTRODUCTION: The mean age of the German population increased over the last years, which resulted in a higher prevalence of cardiovascular diseases, type 2 diabetes, cognitive impairment, sarcopenia and bone fractures. Current evidence indicates a preservation of human wellbeing in the elderly by a healthy diet, although the recommended macronutrient composition and quality remains unclear and needs further long-term investigation. In this context we investigate the effect of a specific dietary pattern on age-related disorders in a randomized controlled multi-center trial (RCT). METHODS: We assess the effect of a specific dietary pattern (NutriAct) with a high proportion of unsaturated fat, plant proteins and fibres (fat 35%-40% of total energy (%E) of which 15%E-20%E monounsaturated fatty acids (MUFA) and 10%E-15%E polyunsaturated fatty acids (PUFA), 15%E-25%E proteins, ≥30 g fibres per day and 35%E-45%E carbohydrates) on age-related impairment of health within a 36-months RCT conducted in the region of Berlin and Potsdam. 502 eligible men (n = 183) and women (n = 319), aged 50 to 80 years, with an increased risk to develop age-related diseases were randomly assigned to either an intervention group focusing on NutriAct dietary pattern or a control group focusing on usual care and dietary recommendations in accordance to the German Nutrition Society (DGE). In the intervention group, 21 nutrition counsellings as well as supplementation of rapeseed oil, oil cake and specific designed foods are used to achieve the intended NutriAct dietary pattern.The primary outcome is a composite endpoint of age-related disorders, including cardiovascular morbidity, decline of cognitive function as well as clinical features of sarcopenia. Secondary outcomes include diet-induced effects on quality of life, depression, frailty, cardiovascular function, bone density, fat distribution pattern, glucose, lipid and energy metabolism, as well as the identification of biomarkers linked with age-related disorders. DISCUSSION: The findings of this trial will provide clinically relevant information regarding dietary effects on age-related impairment of health and will contribute to the definition of the optimal macronutrient composition in the context of healthy aging in the German population.