Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 450999875 Background Transmembrane protein 43 (TMEM43) is a phylogenetically highly conserved and ubiquitously expressed protein with unknown function. The protein contains four transmembrane domains located in the inner nuclear envelope and the endoplasmic reticulum (ER). A large acidic domain located between the first and second transmembrane domains, with unknown function, is exposed to the ER lumen. TMEM43-c.1073C>T is a rare fully penetrant mutation that leads to arrhythmogenic right ventricular cardiomyopathy type 5 (ARVC5). ARVC5 is associated with myocardial fibrosis, fibrofatty replacement and progressive loss of right ventricular myocardial tissue and severe arrhythmias causing sudden cardiac death (SCD) especially in males. The pathomechanism of ARVC5 is not well understood. Methods We isolated and cultivated primary dermal fibroblasts of three different individuals carrying TMEM43-c.1073C>T (p.S358L). Proteins were isolated from cell cultures and analysed by Orbitrap mass spectrometry. Proteome data of the mutation carriers were compared to TMEM43 wildtype control fibroblasts. Additionally, TMEM43-p.S358L and control fibroblasts were investigated by transmission electron microscopy (TEM). Results A total of 9 proteins were upregulated in fibroblasts expressing TMEM43-p.S358L (p<0.003). Of note, proteins involved in fatty acid metabolism, such as acyl-coenzym A (CoA) thioesterase 1 encoded by the gene ACOT1, and Malonate-CoA ligase encoded by ACSF3 were strongly upregulated (FC>3 or >2, respectively). ACOT1 catalyses hydrolysis acyl-CoAs to long chain fatty acids and CoA. ACSF3 catalyses the formation of thioesters between fatty acids and CoA. ACOT1 and ACSF3 regulate the intracellular levels of free fatty acids and are expressed in the cardiomyocytes of the human myocardium. TEM images of TMEM43-p.S358L carriers show an accumulation of multilamellar vesicles, which may support the dysregulation of the lipid metabolism. Conclusion The differentially regulated proteins in dermal fibroblasts and the accumulation of multilamellar vesicles suggest a dysregulation of the lipid metabolism by TMEM43-p.S358L, which may also have relevance for the development of myocardial fibrofatty replacement contributing to ARVC5.

Purpose Ventricular assist devices (VAD) are implanted in patients for bridging to heart transplantation (BTT) or nowadays in an increasing number of cases for destination therapy. However, about 2% of the patients develop spontaneously myocardial recovery for unknown reasons (BTR). Currently, myocardial recovery is not predictable, since reliable biomarkers are lacking. The aim of our study was the identification of novel biomarkers for myocardial recovery. Methods and Materials Total-RNA from left ventricular (LV) samples of 7 rejected donor hearts (NF), and LV-apex samples of 7 BTR- and 7 BTT-patients from VAD-implantation were isolated. NF-, BTR-, BTT-patients were matched according to age, gender and etiology. We analysed the myocardial transcriptome using Affymetrix-chips for the identification of secretory proteins. Differentially expressed transcripts were confirmed by real time RT-PCR. Expression profiling was evaluated by principal component analysis (PCA) and target gene identification. Transcripts of secretory proteins were analysed by enzyme linked immunosorbant assay (ELISA) for differences in the plasma at the time VAD-implantation. Results The principal component analysis (PCA) did not reveal clear separation of the HF samples. However, transcripts related to the immune system like plasma TNF-alpha stimulated gene 14 (TSG14) and interferon inducible protein 10kD (CXCL10) are by trend increased in BTR-samples compared to controls. Of note, TSG14 and CXCL10 were not different between BTR and BTT patients. However, both proteins were significantly elevated in VAD-patients before device implantation. Conclusions Molecular differences in the myocardium of patients with and without myocardial recovery are small. However, the identified transcripts such as TSG14 or CXCL14 related to immune-modulatory functions may indicate an uncomplete cardiac remodelling in patients weaned from the device. Both markers are significantly increased in heart failure patients.

Objectives: Endothelins are potent vasoconstrictors mediating their activity through endothelin receptor-A (ETA) and -B (ETB) belonging to the superfamily of G-protein-coupled receptors. In the heart endothelin has positive chronotropic as well as positive inotropic effects. Furthermore it mediates cell proliferation through induction of myocardial cell hypertrophy and fibrosis. Ventricular assist devices (VAD) are implanted in terminal failing patients as a bridge for heart-transplantation. In some cases mechanical circulatory support (MCS) leads to improvement of the cardiac phenotype. However, the endothelin system in unloaded failing myocardium is incompletely understood.

Upregulation of the extracellular matrix (ECM) is a hallmark of heart failure (HF). During ventricular assist device (VAD) support highly controversal data were published so far, revealing upregulation, no regulation or even downregulation of the collagen fraction during VAD-support. We therefore analysed in a comparable high number of VAD-patients 4-hydroxyproline (4OHP) and the regulation of the prolyl-4-hydroxylase (P4H) being the key enzyme for collagen synthesis.

Purpose: The upregulation of the extracellular matrix is a hallmark of heart failure (HF). During VAD-support highly controversal data were published so far, revealing upregulation, no regulation or even downregulation of the collagen fraction during VAD-support. We therefore analysed in a comparable high number of patients 4-hydroxyproline (4OHP) and the regulation of the prolyl-4-hydroxylase (P4H), which is a key enzyme for synthesis of collagen within the myocardium.

Background: in this study we analyzed putative biomarkers for myocardial remodeling in plasma from 55 endstage heart failure patients with the need for mechanical circulatory support (MCS). We compared our data to 40 healthy controls and examined if MCS by either ventricular assist devices or total artificial hearts has an impact on plasma concentrations of remodeling biomarkers.Methods & Plasma biomarkers were analysed pre and 30 days post implantation of a MCS device using Results: commercially available enzyme linked immunosorbent assays (ELISA). We observed that the plasma concentrations of remodeling biomarkers: tissue inhibitor of metalloproteinase 1 (TIMP1), tenascin C (TNC), galectin 3 (LGALS3), osteopontin (OPN) and of neurohumoral biomarker brain natriuretic peptide (BNP), are significantly elevated in patients with terminal heart failure compared to healthy controls. We did not find elevated plasma concentrations for matrix metalloproteinase 2 (MMP2) and procollagen I C-terminal peptide (PCIP). However, only BNP plasma levels were reduced by MCS, whereas the concentrations of remodeling biomarkers remained elevated or even increased further 30 days after MCS. LGALS3 plasma concentrations at device implantation were significantly higher in patients who did not survive MCS due to multi organ failure (MOF).Conclusions: Our findings indicate that mechanical unloading in endstage heart failure is not reflected by a rapid reduction of remodeling plasma biomarkers.

Aims: There is general agreement that mechanical circulatory support of the failing myocardium leads to regression of cardiomyocyte hypertrophy. However, little is known on the response to unphysiological unloading of the terminal failing ventricle by non-pulsatile ventricular assist devices (VAD). Therefore we analysed the circumferential diameters (CD) in cryosections of cross sectioned cardiomyocytes (CM) by computer assisted histometry.

Purpose: Mechanical unloading by ventricular assist devices (VAD) leads to significant gene-expression changes often summarized as reverse remodeling. However, little is known on individual transcriptome changes during VAD-support and its relationship to non-failing hearts (NF). In addition no data are available for the transcriptome regulation during non-pulsatile VAD-support. Therefore we analysed gene-expression patterns of 34 paired samples from VAD-supported (including 6 non-pulsatile VADs) and 10 non-failing control hearts (NF). We used the first total human genome-array available.

Teleradiologie und Telemedizin werden in den nächsten Jahren immer weiter zusammenwachsen. Im Bereich ehealth stehen deutsche und internationale Projekte an, die eine sektorübergreifende Kommunikation auf zunehmend hohem Niveau ermöglichen werden. Zu den Entwicklungen der informationstechnischen Voraussetzungen hat die Radiologie einen wesentlichen Beitrag geleistet; die Teleradiologie ist eine führende Telemedizinanwendung. Insbesondere mit Standards wie DICOM e-mail ist eine sektorübergreifende Kommunikation mit einer Vielzahl von Partnern sowie eine Anbindung an Strukturen und Dienste der sektorübergreifenden elektronischen Patientenakte (SEPA) und der elektronischen Gesundheitskarte (eGk) möglich. Mit neuen Konzepten, z.B. aus der IHE – Initiative, wird auch eine Zusammenarbeit in komplexeren Strukturen des Gesundheitswesens mit hoher Funktionalität und Vorteilen für die Beteililgten unter Wahrung des Datenschutzes und der Patientenrechte vorbereitet.

Background: Whether adverse structural changes in the myocardium due to remodelling can be reversed by ventricular assist device (VAD) support in patients with end-stage heart failure is controversial.Aims: To investigate the effect of VAD support on the extra-cellular matrix.Methods: We analysed the collagen content in terminal failing ventricles of VAD-patients and donor hearts using 4-hydroxyproline for total collagen and real time RT-PCR for fibronectin (IN), collagen I alpha 1 (Col1A1), III alpha 1 (Col3A1) and TGF beta I analysis.Results: Compared to donor hearts we found similar increases in Col1A1 and TGF betal but not Col3A1 and IN mRNAs, which were similar in the myocardium from patients receiving a VAD or heart transplant. However, patients receiving ACE-I during VAD-support had lower Col1A1 mRNA content at transplantation. The total collagen content was not influenced by mechanical unloading or by ACE-I medication.Conclusion: Mechanical unloading by VAD does not reduce the collagen content of the terminal failing ventricle possibly due to increased TGF betal levels. However, Col1A1 production may be reduced by ACE-I medication during VAD support. (c) 2005 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

Objectives: In failing myocardium the beta-adrenergic signal transduction is blunted due to receptor-downregulation, -modification and upregulation of inhibitory G-protein subunits (Gi-alpha). We and others showed, that ventricular assist device (VAD) support leads to upregulation of beta1-adrenergic receptors. However, the regulation of inhibitory G-proteins is not known. Thus, we analysed the expression of Gi-alpha 2 and -alpha 3 on mRNA and protein level.

Objectives: Loading of the increased terminal failing ventricle in dilated cardiomyopathy is claimed to be of importance for the remodeling process of the failing ventricle due to wall tension. The extracellular matrix provides a scaffold for cardiomyocytes during heart failure and is a hallmark of remodeling. Little is known on the influence of the collagen scaffold on the relative expression changes of BNP under VAD support.

Purpose: Ventricular remodeling of failing myocardium has impact on the outcome in chronic heart failure. Increased expression of extracellular matrix proteins (ECM) is triggered by wall strain in failing hearts. Whether remodeling can be reversed by mechanical unloading remains controversial. To enhance recovery our MCS patients (pts) receive ACE inhibitors (ACE-I) unless they cannot tolerate them. To determine the influence of ACE -I we analyzed total collagen and rnRNA of ECM. Methods: In terminal failing ventricles of 26 HTX candidates bridged by MCS we analyzed collagen by 4-hydroxyproline analysis and mRNA by real time RT-PCR of fibronectin (FN), collagen 1 alpha 1 (collAl), 3 alpha 1 (col3Al) and transforming growth factor beta 1 (TGF beta 1). Findings were compared for pts receiving ACE-I and those without and by comparison to non-failing donor hearts. Results: CollAl and TCF betal were significantly increased in MCS pts compared to non-failing donor hearts; mean levels did not differ at time of MCS implantation and htx. Col 3A1 and FN mRNA were not significantly increased in failing hearts, neither at MCS implant time nor at htx. Pts receiving ACE-I during MCS revealed significantly lower CollAl mRNA contents at Htx than those without ACE-I. Total collagen content was unchanged by mechanical unloading and ACE-I. Conclusion: Mechanical unloading by MCS does not reduce the collagen content of failing ventricles, probably due to increased TCF betal levels. However, the neo-synthesis of collAl can be reduced by ACE -I medication under MCS support.

Objectives: In terminal failing hearts beta adrenergic receptors (bAR) are downregulated and intracellular adrenergic signal transduction is blunted. Mechanical circulatory support by ventricular assist devices (VAD) is used to bridge patients to heart transplantation (HTx). Mechanical unloading by VAD is regarded to induce reverse remodeling and to restore adrenergic response in HTx candidates. However little is known on the relative regulation of bAR subtype and bAR signal-transduction.

Background: Chronic heart failure is a multifactorial, progressive disease of many causes and is associated with complex ventricular remodeling. Deposition of extracellular matrix proteins and sarcomeric disarray of the myocytes occur in end-stage heart failure. Ventricular assist devices (VAD), implanted as bridge to transplantation, may reverse ventricular remodeling. Although successfully weaning patients from VAD support has been reported, it is not clear to what degree reversal of remodeling,occurs in unloaded failing hearts. Because collagen deposition, and ultrastructural disarray are hallmarks of myocardial remodeling, we analyzed the myocardial ultrastructure and collagen content of VAD-supported hearts before and after mechanical unloading.Methods: We used amino acid analysis to measure collagen content (4-hydroxyproline content) in 24 transplant candidates receiving VAD support. We used transmission electron microscopy to examine the ultrastructure in 6 patients receiving VAD support.Results: The 4-hydroxyprohne content increased significantly at VAD implantation and was not altered by mechanical unloading. The ultrastructure showed signs of persisting. cardiomyopathy.Conclusion: Mechanical unloading does not alter the total collagen content of the supported, failing heart. Thus, structural reversal of the remodeling process associated with heart failure is not a general phenomenon in mechanically unloaded hearts.

BACKGROUND:Myocardial recovery is observed in some end-stage heart failure patients after mechanical circulatory support. The sarcoplasmic reticulum Ca(2+)-adenosine triphosphatase (Ca2+-ATPase) activity is down-regulated in failing myocardium and contributes to heart failure-associated contraction/relaxation abnormalities. Regulation of Ca(2+)-ATPase after mechanical support was shown to be heterogeneous. Thus, we analyzed Ca(2+)-ATPase activity and protein expression in the paired myocardial samples of 21 patients supported by ventricular assist devices to identify factors that influence restoration of the Ca(2+)-transient after ventricular assist device support. METHODS:We measured Ca(2+)-ATPase activity using a reduced nicotinamide-adenine dinucleotide-coupled reaction, determined sarcoplasmic reticulum Ca(2+)-dependent ATPase protein using Western blotting, and determined 4-hydroxyproline using amino-acid analysis. RESULTS:The mean Ca(2+)-ATPase activity decreased at assist-device implantation and slightly increased at transplantation, but remained significantly lower than in non-failing donor hearts. However, individual responses were heterogeneous. Patients with older age, increased left ventricular diameter, and increased 4-hydroxyproline content showed down-regulation of Ca(2+)-ATPase activity, whereas we found up-regulation in patients with low values for these parameters after assist-device support. CONCLUSIONS:Sarcoplasmic reticulum Ca(2+)-ATPase activity, which influences the myocardial Ca(2+)-transient, generally is not restored to normal values in assist-device-supported hearts, but depends on a combined score of the left ventricular end-diastolic diameter, degree of ventricular fibrosis, and age of the patient at the time of assist-device implantation.