The European livestock resistome

Metagenomic sequencing has proven to be a powerful tool in the monitoring of antimicrobial resistance (AMR). Here, we provide a comparative analysis of the resistome from pigs, poultry, veal calves, turkey, and rainbow trout, for a total of 538 herds across nine European countries. We calculated the effects of per-farm management practices and antimicrobial usage (AMU) on the resistome in pigs, broilers, and veal calves. We also provide an in-depth study of the associations between bacterial diversity, resistome diversity, and AMR abundances as well as co-occurrence analysis of bacterial taxa and antimicrobial resistance genes (ARGs) and the universality of the latter. The resistomes of veal calves and pigs clustered together, as did those of avian origin, while the rainbow trout resistome was different. Moreover, we identified clear core resistomes for each specific food-producing animal species. We identified positive associations between bacterial alpha diversity and both resistome alpha diversity and abundance. Network analyses revealed very few taxa-ARG associations in pigs but a large number for the avian species. Using updated reference databases and optimized bioinformatics, previously reported significant associations between AMU, biosecurity, and AMR in pig and poultry farms were validated. AMU is an important driver for AMR; however, our integrated analyses suggest that factors contributing to increased bacterial diversity might also be associated with higher AMR load. We also found that dispersal limitations of ARGs are shaping livestock resistomes, and future efforts to fight AMR should continue to emphasize biosecurity measures.IMPORTANCEUnderstanding the occurrence, diversity, and drivers for antimicrobial resistance (AMR) is important to focus future control efforts. So far, almost all attempts to limit AMR in livestock have addressed antimicrobial consumption. We here performed an integrated analysis of the resistomes of five important farmed animal populations across Europe finding that the resistome and AMR levels are also shaped by factors related to bacterial diversity, as well as dispersal limitations. Thus, future studies and interventions aimed at reducing AMR should not only address antimicrobial usage but also consider other epidemiological and ecological factors.

Knowledge Transfer and Networking Upon Implementation of a Transdisciplinary Digital Health Curriculum in a Unique Digital Health Training Culture: Prospective Analysis

Background

Digital health has been taught at medical faculties for a few years. However, in general, the teaching of digital competencies in medical education and training is still underrepresented.

Objective

This study aims to analyze the objective acquisition of digital competencies through the implementation of a transdisciplinary digital health curriculum as a compulsory elective subject at a German university. The main subject areas of digital leadership and management, digital learning and didactics, digital communication, robotics, and generative artificial intelligence were developed and taught in a transdisciplinary manner over a period of 1 semester.

Methods

The participants evaluated the relevant content of the curriculum regarding the competencies already taught in advance during the study, using a Likert scale. The participants' increase in digital competencies were examined with a pre-post test consisting of 12 questions. Statistical analysis was performed using an unpaired 2-tailed Student t test. A P value of <.05 was considered statistically significant. Furthermore, an analysis of the acceptance of the transdisciplinary approach as well as the application of an alternative examination method (term paper instead of a test with closed and open questions) was carried out.

Results

In the first year after the introduction of the compulsory elective subject, students of human medicine (n=15), dentistry (n=3), and medical biotechnology (n=2) participated in the curriculum. In total, 13 participants were women (7 men), and 61.1% (n=11) of the participants in human medicine and dentistry were in the preclinical study stage (clinical: n=7, 38.9%). All the aforementioned learning objectives were largely absent in all study sections (preclinical: mean 4.2; clinical: mean 4.4; P=.02). The pre-post test comparison revealed a significant increase of 106% in knowledge (P<.001) among the participants.

Conclusions

The transdisciplinary teaching of a digital health curriculum, including digital teaching methods, considers perspectives and skills from different disciplines. Our new curriculum facilitates an objective increase in knowledge regarding the complex challenges of the digital transformation of our health care system. Of the 16 student term papers arising from the course, robotics and artificial intelligence attracted the most interest, accounting for 9 of the submissions.

Empagliflozin inhibits increased Na influx in HFpEF cardiomyocytes and reduces arrhythmic activity in human atrial trabeculae

Background

Heart failure with preserved ejection fraction (HFpEF) is a major health problem associated with substantial morbidity and mortality. However, the underlying pathophysiological mechanisms are poorly understood, and effective treatment strategies are scarce. Importantly, SGLT2i, which have been suggested to improve cellular Na and Ca homeostasis in HFrEF, have recently been shown to also improve clinical outcomes in patients with HFpEF. Interestingly, post-hoc analyses of clinical data suggest an involvement of anti-arrhythmic effects of SGLT2i.

Purpose

We tested, if isolated human atrial cardiomyocytes from patients with HFpEF exhibit an increased Na influx that is responsive to treatment with the SGLT2i empagliflozin (Empa) and if Empa has anti-arrhythmic properties in human atrial trabeculae.

Methods

Atrial biopsies were obtained from 101 patients undergoing elective cardiac surgery. Na influx was measured as increase in [Na]i during Na/K-ATPase inhibition in isolated cardiomyocytes loaded with the Na-sensitive fluorescence dye Asante Natrium Green–2 AM (ANG-2). Western Blot and HDAC4 pulldown assay were used to investigate NaV1.5 expression/phosphorylation as well as CaMKII expression/autophosphorylation and activity. Anti-arrhythmic effects of Empa were evaluated as the reduction in premature atrial complexes (PACs), which were induced in electrically field-stimulated (1Hz) human atrial trabeculae by superfusion with isoproterenol (100 nM) and high Ca (3.5 mM).

Results

Compared to patients without heart failure (NF), Na influx was almost doubled in HFpEF patients (NF vs HFpEF: 0.21±0.02 vs 0.38±0.04 mmol/L/min (N=7 vs 18); p=0.005) (Fig. 1D, E). CaMKII expression, CaMKII autophosphorylation, CaMKII activity, and CaMKII-dependent NaV1.5 phosphorylation were significantly increased in atrial biopsies of HFpEF patients, whereas NaV1.5 protein abundance remained unchanged (Fig. 1A–C). Consistent with these results, the increased Na influx was significantly reduced by treatment with the specific CaMKII inhibitor autocamtide-2 related inhibitory peptide (AIP) and the late INa inhibitor tetrodotoxin (TTX) (Fig. 1D, E). Importantly, Empa also abolished the increased Na influx in HFpEF cardiomyocytes (Fig. 1D, E). Multivariate linear regression analysis, adjusting for clinical co-variates, revealed HFpEF to be an independent predictor of cardiomyocyte Na handling. In line with Empa-mediated inhibition of Na influx, the frequency of PACs in human atrial trabeculae was significantly reduced by Empa (Fig. 1F, G).

Conclusion

This is the first study to demonstrate increased Na influx in human cardiomyocytes from HFpEF patients potentially by an increased CaMKII-dependent NaV1.5 phosphorylation. Excitingly, treatment with Empa decreases this Na influx in HFpEF cardiomyocytes and reduces isoproterenol-induced arrhythmic activity in human atrial trabeculae, which could contribute to the cardioprotective effects of this drug in patients with HFpEF.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Else Kröner-Fresenius-Stiftung,Deutsche Forschungsgemeinschaft

Electrophysiological remodeling in tachycardia-induced cardiomyopathy

Background

Tachycardia-induced cardiomyopathy (TCM) is a reversible and likely underrecognized form of heart failure. Thus, a better understanding of the TCM-pathophysiology is warranted as the underlying early mechanisms that mediate the progression of TCM remain unclear.

Purpose

This study aimed to identify the cellular mechanisms of TCM.

Methods and results

Human induced pluripotent stem cell cardiomyocytes (iPSC-CM) were utilized as a translational human-based model. We performed chronic tachycardic (120 bpm) or normofrequent (control, 60bpm) cell culture pacing to study cellular changes during TCM progression.

Already after 24h of tachycardic stimulation of iPSC-CM, we detected a decrease in Ca transient amplitude compared to control (Fura-2, n=49/44 cells/9 differentiations). Diastolic Ca levels and cytosolic Ca elimination were not affected after 24h of tachycardia (n=49/44/9). We detected no difference in sarcoplasmic reticulum (SR) Ca load (assessed via caffeine application) or SERCA activity (Ksys-Kcaff) after 24h of tachycardia (n=13/15/5). However, demonstrating the progress of TCM, 7d of tachycardia resulted in progressive decline of Ca transient amplitude together with an impaired Ca elimination, while diastolic Ca concentration was unchanged (n=73/66/8). These changes may underlie the reduced systolic force and impaired relaxation in TCM. We could explain these results by a significantly reduced SR Ca load and a diminished SERCA activity after 7d tachycardia (n=13/7 vs. 13/4). Using confocal microscopy (Fluo-4) we detected no difference in SR Ca spark frequency after 24h of tachycardia (n=82/66/8), while 7d of tachycardia caused an increase of Ca spark frequency (n=76/79/7), which is a typical hallmark of maladaptive remodeling in HF and likely underlie the reduced SR Ca load. Voltage clamp data of late Na current (INaL) showed no difference in INaL after 24h of stimulation (n=17/6 vs. 19/7), whereas INaL was increased after 7d of tachycardia (n=26/7 vs. 19/6). Accordingly, whole-cell current clamp experiments revealed a prolongation of the action potential after 7d of tachycardia compared to control (n=21/6 vs. 19/5), while no difference of action potential duration could be detected after 24h (n=37/31/8). Resting membrane potential and action potential amplitude were not changed. Finally, we investigated tachycardia-mediated effects on explanted human failing hearts. 8h of tachycardic stimulation (120 bpm) of human failing ventricular trabeculae already compromised systolic force, and diastolic tension and relaxation time were markedly increased compared to control (60bpm, n=8/6 trabeculae /7/6 human hearts).

Conclusion

This study demonstrates that persistent tachycardia adversely alters cardiomyocyte excitation-contraction coupling via electrophysiological cellular remodeling. Our translational investigation in human myocardium may help to understand the pathophysiology of an underrated but prevalent disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Else Kröner-Fresenius-Stiftung (EKFS)Deutsche Gesellschaft für Innere Medizin

Investigations regarding the role of NOS1AP in the heart using a conditional overexpression mouse model

Background

35.3% of deaths in 2019 in Germany are caused by cardiovascular diseases (Destatis). 95% of these people were 60 years and older. To increase survival rate in elderly patients we investigate the relevance of altered expression of neuronal nitric oxide synthase 1 (NOS1) adaptor protein (NOS1AP) acting as an L-type calcium channel (CaV1.2) modulator via directing NOS1 to CaV1.2 on cardiac electrophysiology. Genome-wide association studies have linked genetic polymorphisms in NOS1AP to variations in QT interval duration (QTc). The QT interval reflects ventricular de- and repolarization. It may predispose individuals to ventricular tachycardia and sudden cardiac death (SCD) if prolonged, shortened or otherwise unregularly. In addition, about 20% of families with a clinically proven diagnosis of long QT syndrome (LQTS) host no mutation in any of the 16 associated genes.

Methods and results

Transgenic mice with conditional overexpression of NOS1AP in cardiac myocytes were used as model organism. We confirmed the interaction of NOS1AP with NOS1 and CaV1.2. Electrocardiography in NOS1AP overexpressing mice showed atrial and ventricular tachycardia both spontaneously and upon programmed stimulation associated with a significant decrease in QTc. Heart rates in NOS1AP overexpressing mice were similar to non-induced animals. Survival was significantly reduced (only 60% after 12 weeks vs. 100% in non-induced mice). Induced QTc alterations and accompanied deaths subsided upon re-administration of doxycycline.

Whole-cell patch-clamp measurements in isolated adult ventricular myocytes were performed and action potential duration at 90% of repolarization (APD90) was significantly reduced in induced transgenic NOS1AP overexpressing mice compared to control littermates.

In addition, we investigated the functional effect of the human SNP rs16847548 (T/C) located within the NOS1AP promoter. The SNP was found to decrease the transcriptional activity of NOS1AP in vitro and therefore, potentially leading to a decrease in NOS1AP expression in humans.

Conclusion

Myocardial overexpression of NOS1AP leads to short QT syndrome with increased susceptibility to atrial and ventricular arrhythmias and cardiac death. In accordance, APD90 is significantly shortened in overexpressing animals. The human SNP rs16847548, which is located in the promoter region of NOS1AP, results in a reduced NOS1AP promoter activity in vitro, hereby providing an explanation for the frequently published elongation of QT intervals. In summary, not only mutations in ion channels themselves but also genetic alterations in the expression of ion channel modulators such as NOS1AP, have an impact on QTc and arrhythmogenesis and represent a promising therapeutic target for LQTS patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Gesundheitscampus Brandenburg (MWFK)

Effects of atrial fibrillation on ventricular remodeling in the human heart

 

Atrial fibrillation (AF) is often found in patients with heart failure (HF). Clinical data indicated that the arrhythmic component of AF alone could contribute to left-ventricular (LV) dysfunction. However, the effects of non-tachycardic AF with arrhythmic excitation of the human LV, are unknown.

We investigated human LV myocardium from patients with sinus rhythm (SR) or normofrequent AF (mean EF&gt;50%, matched clinical data, derived from septal resections during AVR). In histological analysis we detected no difference between SR (n=17 patients) and AF patients (n=18) regarding the amount and distribution of fibrosis. We isolated human LV cardiomyocytes (CM) and studied cellular Ca-handling (Fura-2). Systolic Ca-transient amplitude of LV CM was reduced in patients suffering from AF (n=8 AF patients vs. 11 SR), while diastolic Ca-levels and Ca-transient kinetics were not significantly changed. These results were confirmed in LV CM from non-failing donors (NF) with AF (n=4 AF patients vs. 8 SR). For the standardized investigation of a normofrequent arrhythmia, we simulated AF in vitro by using arrhythmic (60 bpm, 40% beat-to-beat variability) or rhythmic (60 bpm) field stimulation. Human LV CM from NF SR patients (n=8) showed an impaired Ca-transient amplitude after 24h arrhythmic culture pacing without changes in diastolic Ca and Ca-transient kinetics. For studying a model suitable for more standardized chronic pacing, we utilized human iPSC cardiomyocytes (iPSC-CM) from healthy donors (n=6). After 7 days, arrhythmically paced iPSC-CM exhibited a reduced systolic Ca-transient amplitude, a trend towards a prolonged Ca-elimination time and a reduced sarcoplasmic reticulum Ca-load. Confocal line-scans of arrhythmically paced cells (Fluo-4 AM) showed an increased diastolic Ca-leak from the sarcoplasmic reticulum, possibly underlying the reduced Ca-load. Coupled with the Ca changes, cytosolic Na was elevated after arrhythmia. We found an increased late INa, which could explain the detrimentally altered Ca/Na-interplay. Accordingly, Patch-clamp experiments revealed a prolonged action potential duration after arrhythmia. We further elucidated the underlying mechanisms of this electrophysiological remodeling by showing that oxidative stress (H2O2, LPO) is increased in the LV of patients suffering from AF (n=6 AF patients vs. 6 SR), which was associated with an enhanced NOX2/-4 activity. Consecutively, Ca2+/calmodulin-dependent protein kinase IIδ (CaMKII) was found to be more oxidized (CaMKII-Met281/282) in the LV of AF patients (n=7 AF patients vs. 7 SR) leading to an increased CaMKII activity, which adversely regulated EC-coupling protein phosphorylation including RyR2 hyperphosphorylation.

Normofrequent arrhythmia/AF impairs human ventricular EC-coupling via increased oxidative stress and enhanced CaMKII. Thus, this translational study provides the first mechanistic characterization and the potential negative impact of isolated AF on the human LV.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Else Kröner-Fresenius-Stiftung (EKFS) and Deutsche Gesellschaft für Innere Medizin

Directed, Elliptic, and Higher Order Flow Harmonics of Protons, Deuterons, and Tritons in Au+Au Collisions at sqrt[s_{NN}]=2.4 GeV

Flow coefficients v_{n} of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sqrt[s_{NN}]=2.4  GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

Atrial fibrillation impairs ventricular function by altering excitation-contraction coupling in the human heart

 

Atrial fibrillation (AF) often co-exists in patients with heart failure (HF). Recent clinical evidence suggests that the arrhythmic component of AF alone may contribute to ventricular dysfunction. However, the pathophysiological effects of a non-tachycardic AF on the human ventricle are unknown. To investigate the effects of normofrequent AF on the human ventricle we investigated ventricular myocardium from patients with preserved ejection fraction with sinus rhythm (SR) or AF in the absence of HF (compensated hypertrophy, EF&gt;50%, matched clinical characteristics). In histological analysis we detected no difference between SR (n=9) vs. AF (n=6) regarding the amount and distribution of fibrosis. For functional investigation, Ca-handling was studied (Fura-2 AM). While systolic Ca-transient amplitude was in trend reduced in isolated human ventricular AF cardiomyocytes, we found a significantly prolonged Ca-elimination time (n=17–22 cells/4 pat.). Using caffeine application, a decreased SR Ca-load in AF was detected, which may be explained by a significant decrease in SERCA2a activity (ksys-kCaff, n=10–12/4 pat.). Patch-clamp experiments revealed a prolonged action potential duration in AF cardiomyocytes (n=5/15 cells).

For the standardized evaluation of the mechanisms of persistent normofrequent arrhythmia, we simulated AF in vitro by using arrhythmic (1 Hz, 40% R-R-variability) or rhythmic (1 Hz) field stimulation. We performed contractility experiments using in-toto isolated human ventricular trabeculae from explanted human hearts. After 8h of pacing, arrhythmically stimulated human trabeculae showed a significantly reduced systolic force, an increase in diastolic tension and a prolonged relaxation (n=11–12 trabeculae/11 pat.). For studying the cellular effects of persistent normofrequent arrhythmia in a model suitable for chronic pacing (up to 7 days), we utilized human iPSC cardiomyocytes (iPSC-CM) from healthy donors (n=6). After 7 days, arrhythmic paced iPSC-CM showed a significantly reduced systolic Ca-transient amplitude, a prolonged Ca-elimination time (n=35/45 cells) as well as a reduced SR Ca-load and a trend towards a lower SERCA2a activity compared to control (n=11 cells). Confocal line-scans (Fluo-4 AM) showed an increased diastolic SR Ca-release, which might also explain the reduced SR Ca-content (n=45/35 cells). Moreover, in irregularly paced iPSC-CM we found significant increased levels of cytosolic Na (n=69 cells each) and in patch-clamp experiments a significantly prolonged action potential duration (n=14/11 cells/3 diff.).

This study demonstrates that a normofrequent arrhythmic ventricular excitation as it occurs in AF impairs human ventricular myocardial function by altering cardiomyocyte excitation-contraction coupling. Thus, this study provides the first translational mechanistic characterization and the potential negative impact of isolated AF in the absence of tachycardia on the human ventricle.

Funding Acknowledgement

Type of funding source: None

Cellular mechanisms of early tachycardia-induced ventricular dysfunction in the human heart

Background

Tachycardia-induced cardiomyopathy (TCM) is a reversible form of ventricular dysfunction caused by persistent tachycardia. Characterization of TCM is mainly based on artificially RV paced animal models. Moreover, the underlying mechanisms and time course from compensation to failure remain unclear. This study aimed to investigate early cellular remodeling of tachycardia-induced myocardial dysfunction in human myocardium.

Methods and results

To elucidate early cellular electrophysiological targets mediating the transition to TCM, we chronically paced (120bpm vs 60bpm control) human induced pluripotent stem cell cardiomyocytes (hiPS-CM) for up to 7d. As a major substrate of cellular myocardial dysfunction, we investigated the influence of chronic tachycardia on cellular Ca cycling. After 24h of persistent tachycardia we detected a significant decrease in Ca transient (CaT) amplitude and reduced diastolic Ca levels (Fura-2). Meanwhile, Ca elimination time (RT80) was unchanged compared to control (n=44/42 cells / 8 diff.). Caffeine application was performed to evaluate sarcoplasmic reticulum (SR) Ca load. We found a shortening of caffeine-induced CaT relaxation time, whereas SR Ca load was unchanged (n=12/13 /8). Further illustrating the transition to TCM, CaT amplitude was progressively decreased after 7d of chronic tachycardia. In contrast to 24h of tachycardia, 7d persistent stimulation resulted in slowed relaxation (RT80, n=75/65 /7). These findings could be explained by a significant reduction of SERCA activity (Ksys-Kcaff) and SR Ca load (n=14/12 / 7). Diastolic Ca concentration remained reduced (n=75/65 /7), in total suggesting a shift to transsarcolemmal Ca elimination.

Sodium measurements (SBFI) revealed a significant increase of intracellular sodium concentration (n=69/69 /5) after 7d of tachycardia.

In patch clamp experiments we detected a prolongation of action potential duration as early as 24h after onset of tachycardia (n=26/21 /4), which persisted throughout 7d of pacing (n=8/12 /3). Resting membrane potential and action potential amplitude were not changed.

Finally, we investigated tachycardia-mediated effects on pre-existing human heart failure (HF). 8h tachycardic stimulation (120bpm) of human HF ventricular trabeculae compromised systolic force, while diastolic tension and relaxation time were markedly increased compared to control (60bpm) (n=7/6 trabeculae /6 human hearts).

The extensive molecular characterization of involved ion channels and pathways mediating transition to TCM is currently under investigation.

Conclusion

This study demonstrates that a persistent tachycardia adversely alters cardiomyocyte excitation-contraction coupling via early electrophysiological cellular remodeling. In pre-existing HF persistent tachycardia strongly aggravates ventricular dysfunction. Our first translational investigation in human myocardium may help to understand the pathophysiology of an underrated and very prevalent disease.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Else-Kröner-Fresenius-Stiftung

Neutral Processes Dominate Microbial Community Assembly in Atlantic Salmon, Salmo salar

In recent years, a wealth of studies has examined the relationships between a host and its microbiome across diverse taxa. Many studies characterize the host microbiome without considering the ecological processes that underpin microbiome assembly. In this study, the intestinal microbiota of Atlantic salmon, Salmo salar, sampled from farmed and wild environments was first characterized using 16S rRNA gene MiSeq sequencing analysis. We used neutral community models to determine the balance of stochastic and deterministic processes that underpin microbial community assembly and transfer across life cycle stage and between gut compartments. Across gut compartments in farmed fish, neutral models suggest that most microbes are transient with no evidence of adaptation to their environment. In wild fish, we found declining taxonomic and functional microbial community richness as fish mature through different life cycle stages. Alongside neutral community models applied to wild fish, we suggest that declining richness demonstrates an increasing role for the host in filtering microbial communities that is correlated with age. We found a limited subset of gut microflora adapted to the farmed and wild host environment among which Mycoplasma spp. are prominent. Our study reveals the ecological drivers underpinning community assembly in both farmed and wild Atlantic salmon and underlines the importance of understanding the role of stochastic processes, such as random drift and small migration rates in microbial community assembly, before considering any functional role of the gut microbes encountered.IMPORTANCE A growing number of studies have examined variation in the microbiome to determine the role in modulating host health, physiology, and ecology. However, the ecology of host microbial colonization is not fully understood and rarely tested. The continued increase in production of farmed Atlantic salmon, coupled with increased farmed-wild salmon interactions, has accentuated the need to unravel the potential adaptive function of the microbiome and to distinguish resident from transient gut microbes. Between gut compartments in a farmed system, we found a majority of operational taxonomic units (OTUs) that fit the neutral model, with Mycoplasma species among the key exceptions. In wild fish, deterministic processes account for more OTU differences across life stages than those observed across gut compartments. Unlike previous studies, our results make detailed comparisons between fish from wild and farmed environments, while also providing insight into the ecological processes underpinning microbial community assembly in this ecologically and economically important species.

P5571MitraClip implantation impairs functional echocardiographic parameters of the left atrium in patients with moderate to severe mitral regurgitation

Background

MitraClip implantation induces hemodynamic unloading and reverse remodeling of the left atrium (LA) and the left ventricle (LV). However little data exist concerning the effects of MitraClip implantation on LA and LV strain reflecting LA and LV function.

Methods and results

From August 2017 to September 2018 62 patients with moderate to severe mitral regurgitation were prospectively enrolled in our single-center RETORT-MR trial (Regensburg Trial on TMVR Techniques in Mitral Regurgitation). All included patients were treated using the MitraClip procedure. Two dimensional speckle tracking echocardiography (2DSTE) of the LA as well as of the LV could be performed in 35 patients with follow-up 2DSTE at four weeks and/or three months after MitraClip implantation. In 25.7% of patients primary mitral regurgitation was present (n=9) and in 74.3% of subjects a secondary entity of mitral regurgitation had been diagnosed (n=26). 57.1% of patients (n=20) suffered from heart failure with preserved ejection fraction (HFpEF) and 42.9% of patients (n=15) had heart failure with reduced ejection fraction (HFrEF). Global longitudinal strain (GLS) was reduced at baseline (−15.3%), at four-week (−14.5%, n=27) and at three-month follow-up (−13.9%, n=28) with no statistically significant differences indicating a sustained mechanical impairment of LV. In contrast significant deterioration was observed in the peak atrial longitudinal strain (PALS) representing LA reservoir function (15.3% at baseline vs. 11.8% at four-week follow-up, n=25, p=0.015 and 16.0% at baseline vs. 13.2% at three-month follow-up, n=25, p=0.03). Similarly to LA reservoir function LA booster function indicating left atrial active contraction was significantly reduced after MitraClip implantation (12.5% at baseline vs. 8.0% at four-week follow-up, n=10, p=0.028). Contrary to LA functional parameters LA size did not change significantly after MitraClip implantation (LA volume index at baseline 74.5 ml/m2 vs. 70.1 ml/m2 at four-week follow-up, n=27, p=0.489).

Conclusion

The present study revealed a deterioration of LA functional parameters (LA reservoir and LA booster function) after MitraClip insertion. It is known that severe mitral regurgitation can cause structural changes of the LA such as fibrosis. MitraClip insertion leads to a significant reduction of regurgitant volumes but structural changes of the LA may not be reversible. In addition MitraClip implantation increases afterload in the LA potentially explaining the observed deterioration of LA functional parameters.

Acknowledgement/Funding

None

1173Anti-heart and anti-intercalated disk autoantibodies: possible novel biomarkers of cardiac sarcoidosis

Background

Sarcoidosis is an immune-mediated disease; cardiac involvement, a granulomatous form of myocarditis, is under-recognised and prognostically relevant, as it can present with significant morbidity and mortality. Anti-heart autoantibodies (AHA) and anti-intercalated disk autoantibodies (AIDA) are reliable autoimmune markers in non-sarcoidosis myocarditis forms.

Purpose

The aim of this study was to assess the potential role of serum AHA and AIDA in cardiac sarcoidosis.

Methods

This is a cross-sectional study on a series of 29 patients with biopsy proven extra-cardiac sarcoidosis and with biopsy-proven or clinically suspected cardiac involvement, who were tested for AHA and AIDA. Patients were recruited in two recruiting tertiary centres, in USA and Italy. AHA and AIDA were detected by indirect immunofluorescence on human myocardium and skeletal muscle. Controls included sera from patients with non-inflammatory cardiac disease (NICD) (n=160), with ischemic heart failure (IHF) (n=141) and normal blood donors (NBD) (n=270).

Results

The frequencies of AHA and of AIDA were higher in sarcoidosis (86%; 62%) than in NICD (8%; 4%), IHF (7%; 2%), NBD (9%; 0%) (p=0.0001; p=0.0001 respectively). Sensitivity and specificity were: 86% and 92% for positive AHA and 62% and 98% for positive AIDA, respectively (see figure).

Figure 1

Conclusions

The detection of serum AHA and AIDA in biopsy-proven or clinically suspected cardiac sarcoidosis supports the involvement of heart-specific autoimmunity in the majority of our cases and may provide a novel non invasive diagnostic marker.

P1596Interaction of CaMKII and NaV1.8 modulates cardiac electrophysiology in human heart failure

Introduction

In human heart failure, electrical remodeling contributes to the risk of arrhythmia generation. Increased expression of Ca/Calmodulin-dependent protein kinase IIδ (CaMKIIδ) and an enhanced persistent Na current (INaL) have been linked to arrhythmogenesis. CaMKIIδ increases INaL via regulation of sodium channels thereby contributing to arrhythmias through early- and delayed-afterdepolarizations (EADs and DADs). Genome-wide association studies (GWAS) have described the implication of the neuronal sodium channel isoform NaV1.8 (SCN10A) in cardiac electrophysiology showing modulation in cardiac conduction. We showed that the expression of the isoform Nav1.8 is significantly increased in human failing cardiomyocytes and contributes substantially to the enhanced INaL.

Purpose

We investigated a potential interaction of CaMKIIδ and NaV1.8 and thereby its role in arrhythmia generation and electrophysiology in human and murine failing hearts.

Methods

Cardiomyocytes were isolated from explanted failing hearts and CaMKIIδ transgenic (TG) mice. We performed immunostainings and co-immunoprecipitation (Co-IP) to show interactions of CaMKIIδ and Nav1.8 in isolated cardiomyocytes and homogenates. Whole-cell patch clamp experiments were conducted in isolated human and murine ventricular cardiomyocytes. Additionally, Ca2+ transients were measured using epifluorescence microscopy with the Ca2+ dye fura-2 (10μmol/L) whereas Ca2+ sparks measurements were performed by using confocal microscopy with the Ca2+ dye fluo-4 (10μmol/L). PF-01247324 is a novel specific NaV1.8 inhibitor (orally bioavailable; 1 μmol/L) and autocamtide inhibitory peptide (AIP, 1 μmol/L) was used to inhibit CaMKIIδ.

Results

Co-immunoprecipitation experiments revealed an association of CaMKIIδ and Nav1.8 in human homogenates compared to healthy controls. Furthermore, immunohistochemistry stainings in isolated human cardiomyocytes showed a co-localization of CaMKIIδ and NaV1.8 at the intercalated disc and t-tubules. We observed a significant reduction of INaL integral and proarrhythmic SR-Ca2+ spark frequency (CaSpF) after addition of either PF-01247324 or the CaMKIIδ inhibitor AIP in failing human and murine ventricular cardiomyocytes. When PF-01247324 and AIP were added together, the decrease in INaL integral and CaSpF was comparable to PF-01247324 alone in human failing cardiomyocytes. Inhibition of NaV1.8 did not show an effect on Ca2+ transient amplitude or Ca2+ transient decay at different stimulation frequencies in CaMKIIδ TG cardiomyocytes.

Conclusion

Our results demonstrate the significance of both CaMKIIδ and NaV1.8 in INaL generation and their detrimental interaction. This data suggest that increased CaMKIIδ activity plays a substantial role for the activation of NaV1.8-mediated late sodium current and SR-Ca2+ leak.

Strong Absorption of Hadrons with Hidden and Open Strangeness in Nuclear Matter

We present the first observation of K^{-} and ϕ absorption within nuclear matter by means of π^{-}-induced reactions on C and W targets at an incident beam momentum of 1.7  GeV/c studied with HADES at SIS18/GSI. The double ratio (K^{-}/K^{+})_{W}/(K^{-}/K^{+})_{C} is found to be 0.319±0.009(stat)_{-0.012}^{+0.014}(syst) indicating a larger absorption of K^{-} in heavier targets as compared to lighter ones. The measured ϕ/K^{-} ratios in π^{-}+C and π^{-}+W reactions within the HADES acceptance are found to be equal to 0.55±0.04(stat)_{-0.07}^{+0.06}(syst) and to 0.63±0.06(stat)_{-0.11}^{+0.11}(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the ϕ meson in nuclear medium is strongly coupled to the K^{-} dynamics. The large difference in the ϕ production off C and W nuclei is discussed in terms of a strong ϕN in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.

CaRMeN: a tool for analysing and deriving kinetics in the real world

This paper presents the concepts of an open software tool (CaRMeN) that can be used to rapidly analyse and derive models, in particular chemical kinetics. The software automates the workflow of comparing model vs. experiment, which must currently be done manually and is thus a time-consuming and error-prone task. The capabilities of the software are illustrated through a case study. Experimental data for the conversion of methane over rhodium catalysts in a wide range of conditions and experimental setups are numerically simulated using five different mechanisms from the literature. The applicability of the mechanisms as well as differences between flow and diffusion models are evaluated. The results show that no single mechanism reliably predicts the chemical conversions of all of the experiments. Although the software was initially developed for chemical kinetics applications, it can also be extended to run any simulation code, and can therefore be applied in other scenarios.

First Measurement of Several β-Delayed Neutron Emitting Isotopes Beyond N=126

The β-delayed neutron emission probabilities of neutron rich Hg and Tl nuclei have been measured together with β-decay half-lives for 20 isotopes of Au, Hg, Tl, Pb, and Bi in the mass region N≳126. These are the heaviest species where neutron emission has been observed so far. These measurements provide key information to evaluate the performance of nuclear microscopic and phenomenological models in reproducing the high-energy part of the β-decay strength distribution. This provides important constraints on global theoretical models currently used in r-process nucleosynthesis.

Subthreshold Ξ^{-} production in collisions of p(3.5 GeV)+Nb

Results on the production of the double strange cascade hyperon Ξ^{-} are reported for collisions of p(3.5  GeV)+Nb, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18 at GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt. For the first time, subthreshold Ξ^{-} production is observed in proton-nucleus interactions. Assuming a Ξ^{-} phase-space distribution similar to that of Λ hyperons, the production probability amounts to P_{Ξ^{-}}=[2.0±0.4(stat)±0.3(norm)±0.6(syst)]×10^{-4} resulting in a Ξ^{-}/(Λ+Σ^{0}) ratio of P_{Ξ^{-}}/P_{Λ+Σ^{0}}=[1.2±0.3(stat)±0.4(syst)]×10^{-2}. Available model predictions are significantly lower than the measured Ξ^{-} yield.