TY - JOUR A1 - Schreiber, Laura M. A1 - Lohr, David A1 - Baltes, Steffen A1 - Vogel, Ulrich A1 - Elabyad, Ibrahim A. A1 - Bille, Maya A1 - Reiter, Theresa A1 - Kosmala, Aleksander A1 - Gassenmaier, Tobias A1 - Stefanescu, Maria R. A1 - Kollmann, Alena A1 - Aures, Julia A1 - Schnitter, Florian A1 - Pali, Mihaela A1 - Ueda, Yuichiro A1 - Williams, Tatiana A1 - Christa, Martin A1 - Hofmann, Ulrich A1 - Bauer, Wolfgang A1 - Gerull, Brenda A1 - Zernecke, Alma A1 - Ergün, Süleyman A1 - Terekhov, Maxim T1 - Ultra-high field cardiac MRI in large animals and humans for translational cardiovascular research JF - Frontiers in Cardiovascular Medicine N2 - A key step in translational cardiovascular research is the use of large animal models to better understand normal and abnormal physiology, to test drugs or interventions, or to perform studies which would be considered unethical in human subjects. Ultrahigh field magnetic resonance imaging (UHF-MRI) at 7 T field strength is becoming increasingly available for imaging of the heart and, when compared to clinically established field strengths, promises better image quality and image information content, more precise functional analysis, potentially new image contrasts, and as all in-vivo imaging techniques, a reduction of the number of animals per study because of the possibility to scan every animal repeatedly. We present here a solution to the dual use problem of whole-body UHF-MRI systems, which are typically installed in clinical environments, to both UHF-MRI in large animals and humans. Moreover, we provide evidence that in such a research infrastructure UHF-MRI, and ideally combined with a standard small-bore UHF-MRI system, can contribute to a variety of spatial scales in translational cardiovascular research: from cardiac organoids, Zebra fish and rodent hearts to large animal models such as pigs and humans. We present pilot data from serial CINE, late gadolinium enhancement, and susceptibility weighted UHF-MRI in a myocardial infarction model over eight weeks. In 14 pigs which were delivered from a breeding facility in a national SARS-CoV-2 hotspot, we found no infection in the incoming pigs. Human scanning using CINE and phase contrast flow measurements provided good image quality of the left and right ventricle. Agreement of functional analysis between CINE and phase contrast MRI was excellent. MRI in arrested hearts or excised vascular tissue for MRI-based histologic imaging, structural imaging of myofiber and vascular smooth muscle cell architecture using high-resolution diffusion tensor imaging, and UHF-MRI for monitoring free radicals as a surrogate for MRI of reactive oxygen species in studies of oxidative stress are demonstrated. We conclude that UHF-MRI has the potential to become an important precision imaging modality in translational cardiovascular research. KW - ultrahigh-field MRI KW - large animal models KW - translational research KW - research infrastructure KW - heart KW - organoid KW - pig KW - cardiovascular MRI Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-317398 SN - 2297-055X VL - 10 ER - TY - THES A1 - Yaqub, Jonathan F. T1 - Geschlechtsspezifische Unterschiede der myokardialen Kontraktilität, Geschlechtshormonspiegel und NT-proBNP-Spiegel bei koronarchirurgischen Patienten T1 - Sex-specific differences in myocardial contractility, sex hormone levels and NT-proBNP levels in coronary bypass surgery patients N2 - Die vorliegende klinisch-experimentelle Arbeit beleuchtet den Zusammenhang zwischen biologischem Geschlecht, den Konzentrationen der Geschlechtshormone Testosteron, Estradiol sowie dem kardialen Protein NT-pro-BNP in vivo und der Kraftentwicklung stimulierter Herzmuskelzellen in vitro. Im Studienzeitraum wurden insgesamt 225 Patienten (35 weiblich, 190 männlich), die sich einer elektiven koronarchirurgischen Operation unter Einsatz der Herz-Lungen-Maschine unterzogen, in die Studie eingeschlossen. Im Rahmen der Operation wurden Herzmuskelproben vom linken und rechten Herzohr gewonnen. Aus diesen wurde experimentell der kontraktile Apparat isoliert. Diese Muskelfaserbündel wurden mittels Immersion in verschieden stark konzentrierten Kalziumbädern zur Kontraktion stimuliert und die resultierende Kraftentwicklung erfasst. Diese Daten wurden den im Patientenblut bestimmten Serumkonzentrationen von Estradiol, Testosteron und NT-pro-BNP gegenübergestellt. Es konnte, auch unter Berücksichtigung der Hormonkonzentrationen, weder eine Korrelation des Patientengeschlechts mit der Kraftentwicklung festgestellt werden, noch korrelierte die Konzentration von NT-pro-BNP mit der Kraftentwicklung im experimentellen Modell. N2 - This clinical-experimental study aims to investigate a potential connection between biological gender, the serum levels of the hormones testosterone and estradiol, as well as the cardiac protein NT-pro-BNP and the force generated by stimulated heart muscle cells in vitro. 225 patients (190 males, 35 females) undergoing coronary bypass surgery were included in the study. During surgery, heart muscle specimens were collected from the left and right atrial auricles. These muscle fiber bundles were experimentally processed to isolate the contractile apparatus, which was then brought to contract by immersion in solutions with varying calcium concentrations. The resulting force values were tracked. No correlation between hormone levels, gender or force was found, nor did the levels of NT-pro-BNP correlate with force generation. KW - Herz KW - heart Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-291163 ER - TY - JOUR A1 - Gergs, Ulrich A1 - Jahn, Tina A1 - Schulz, Nico A1 - Großmann, Claudia A1 - Rueckschloss, Uwe A1 - Demus, Uta A1 - Buchwalow, Igor B. A1 - Neumann, Joachim T1 - Protein phosphatase 2A improves cardiac functional response to ischemia and sepsis JF - International Journal of Molecular Sciences N2 - Reversible protein phosphorylation is a posttranslational modification of regulatory proteins involved in cardiac signaling pathways. Here, we focus on the role of protein phosphatase 2A (PP2A) for cardiac gene expression and stress response using a transgenic mouse model with cardiac myocyte-specific overexpression of the catalytic subunit of PP2A (PP2A-TG). Gene and protein expression were assessed under basal conditions by gene chip analysis and Western blotting. Some cardiac genes related to the cell metabolism and to protein phosphorylation such as kinases and phosphatases were altered in PP2A-TG compared to wild type mice (WT). As cardiac stressors, a lipopolysaccharide (LPS)-induced sepsis in vivo and a global cardiac ischemia in vitro (stop-flow isolated perfused heart model) were examined. Whereas the basal cardiac function was reduced in PP2A-TG as studied by echocardiography or as studied in the isolated work-performing heart, the acute LPS- or ischemia-induced cardiac dysfunction deteriorated less in PP2A-TG compared to WT. From the data, we conclude that increased PP2A activity may influence the acute stress tolerance of cardiac myocytes. KW - protein phosphorylation KW - PP2A KW - transgenic mice KW - heart KW - LPS KW - sepsis KW - ischemia Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284035 SN - 1422-0067 VL - 23 IS - 9 ER - TY - JOUR A1 - Weiß, Emil A1 - Ramos, Gustavo Campos A1 - Delgobo, Murilo T1 - Myocardial-Treg crosstalk: How to tame a wolf JF - Frontiers in Immunology N2 - The immune system plays a vital role in maintaining tissue integrity and organismal homeostasis. The sudden stress caused by myocardial infarction (MI) poses a significant challenge for the immune system: it must quickly substitute dead myocardial with fibrotic tissue while controlling overt inflammatory responses. In this review, we will discuss the central role of myocardial regulatory T-cells (Tregs) in orchestrating tissue repair processes and controlling local inflammation in the context of MI. We herein compile recent advances enabled by the use of transgenic mouse models with defined cardiac antigen specificity, explore whole-heart imaging techniques, outline clinical studies and summarize deep-phenotyping conducted by independent labs using single-cell transcriptomics and T-cell repertoire analysis. Furthermore, we point to multiple mechanisms and cell types targeted by Tregs in the infarcted heart, ranging from pro-fibrotic responses in mesenchymal cells to local immune modulation in myeloid and lymphoid lineages. We also discuss how both cardiac-specific and polyclonal Tregs participate in MI repair. In addition, we consider intriguing novel evidence on how the myocardial milieu takes control of potentially auto-aggressive local immune reactions by shaping myosin-specific T-cell development towards a regulatory phenotype. Finally, we examine the potential use of Treg manipulating drugs in the clinic after MI. KW - Tregs (regulatory T cells) KW - Foxp3 KW - myocardial infarction KW - heart KW - fibrosis KW - T-cells Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-275591 SN - 1664-3224 VL - 13 ER - TY - THES A1 - Augustin, Anne Marie T1 - Auswirkung der SPRED2-Defizienz auf die kardiale Funktion und Beeinflussung durch die Behandlung mit dem Aldosteronantagonisten Eplerenon T1 - Impact of SPRED2-deficiency on cardiac function and influence through treatment with aldosterone receptor antagonist eplerenone N2 - SPRED2 ist ein Inhibitor des Ras/ERK-MAPK-Signalwegs. Um die Folgen einer SPRED2-Defizienz zu erforschen, wurden im Rahmen vorheriger von Ullrich et al. durchgeführter Untersuchungen mittels Gene-Trap-Methode bereits mannigfaltige Auffälligkeiten im Phänotyp der SPRED2-Mäuse festgestellt. So zeigten die Tiere einen Hypochondroplasie-ähnlichen Zwergenwuchs, Verhaltensauffälligkeiten, einen krankhaft gesteigerten Wasserkonsum und nicht zuletzt eine deutlich reduzierte Lebenserwartung im Vergleich mit den WT-Tieren. Des Weiteren fielen erhöhte Aldosteronspiegel auf, die bei näheren Untersuchungen nicht einer erhöhten Aktivität des RAAS geschuldet zu sein schienen. Vielmehr zeigte sich eine deutlich erhöhte Aldosteron-Synthase-Expression in der Nebennierenrinde. Erste Hinweise darauf, dass die SPRED2-Defizienz auch Auswirkungen auf den kardiologischen Phänotyp haben könnte, ergaben sich bereits bei initialen Untersuchungen von Ullrich et al. So konnte bei den SPRED2-KO-Tieren neben hämodynamischer Auffälligkeiten eine gesteigerte Herz-Körpergewicht-Ratio festgestellt werden. Die im Rahmen dieses Folgeprojekts durchgeführten Untersuchungen sollten die Frage klären, ob die Defizienz des SPRED2-Gens Auswirkungen auf die Herzleistung hat und hierüber die verkürzte Lebenserwartung der KO-Tiere verschulden könnte. Hierfür wurden zunächst Untersuchungen der elektrischen kardialen Aktivität mittels EKG und Elektrophysiologischer Untersuchung durchgeführt. Die Ermittlung von Herzrhythmusstörung und die Quantifizierung derselben spielte hierbei eine besondere Rolle. Des Weiteren sollte mit der Durchführung von PSR-Färbungen zur Bestimmung des kardialen Kollagengehaltes histologischen Fragestellungen Rechnung getragen werden. Aufgrund des bereits aus den vorherigen Studien bekannten Hyperaldosteronismus der KO-Tiere stellte sich darüber hinaus die Frage, ob die im Rahmen der Studie feststellbaren kardiologischen Auffälligkeiten als Konsequenz der gesteigerten Aldosteronwerte, oder aber als direkte Folge des Genotyps gewertet werden müssen. Aus diesem Grund wurden alle oben genannten Untersuchungen mit Tieren, welche einer Behandlung mit dem Aldosteronantagonisten Eplerenon zugeführt worden waren, wiederholt. Bei der Auswertung der basalen Ruhe- und Stress-EKGs zeigten sich einige Parameter bei den KO-Tieren pathologisch verändert. So war das QRS-Intervall, als Korrelat zur intraventrikulären Überleitungszeit, bei den KO-Mäusen verlängert, im Stress-EKG waren darüber hinaus sowohl die Dauer der P-Welle als auch des PQ-Intervalls erhöht. Durch die Behandlung mit Aldosteron waren diese Unterschiede zwischen WT- und KO-Gruppe teilweise nicht mehr feststellbar. Das die atrioventrikuläre Überleitungszeit abbildende PQ-Intervall war sowohl im Vergleich mit dem behandelten WT, als auch mit dem unbehandelten WT nicht mehr signifikant erhöht. Auch die Länge des QRS-Komplexes näherte sich unter Eplerenon-Behandlung dem der unbehandelten WT-Tiere an und sank bei der Stress-EKG-Auswertung sogar unterhalb des Signifkanzniveaus. Bei der EKG-Analyse in Bezug auf Arrhythmien ergab sich bei Gegenüberstellung der basalen WT- und KO-Gruppe eine deutlich gesteigerte Vulnerabilität für Herzrhythmusstörungen bei den KO-Tieren. Durch die Behandlung mit Eplerenon konnte hierbei ein deutlicher Erfolg erzielt werden mit signifikanter Reduktion der Arrhythmieereignisse. Die elektrophysiologische Untersuchung ergab neben unauffälligen Parametern der Funktion des Sinusknotens und der AV-Überleitung ebenfalls Hinweise für eine gesteigerte Empfindlichkeit für Arrhythmien. Die durch EPU induzierten Arrhythmien zeigten sich durch Eplerenon-Behandlung gleichermaßen rückgängig. Mittels Kollagenfärbung konnte der initiale Verdacht, dass die SPRED2-KO-Tiere zu einer vermehrten kardialen Fibrosierung neigen, bestätigt werden. Dabei zeigte sich durch die Behandlung mit Eplerenon eine deutliche Beeinflussung und Reduktion des kardialen Kollagengehaltes. Insgesamt lässt sich schlussfolgern, dass die mannigfaltigen phänotypischen Effekte, die die SPRED2-Defizienz bedingt, nur teilweise dem Hyperaldosteronismus der Tiere geschuldet sind und durch therapeutische Einflussnahme auf diesen auch nur partiell kompensiert werden können. N2 - SPRED proteins are inhibitors of the Ras/ERK/MAPK signaling pathway, an evolutionary highly conserved and very widespread signaling cascade regulating cell proliferation, differentiation, and growth. To elucidate physiological consequences of SPRED2 deficiency, SPRED2 KO mice were generated by a gene trap approach and heart investigations were systematically performed. An initial phenotypical characterization in studies of Ullrich et al showed a hypochondroplasia-like dwarfism, abnormally high water uptakes, behavioural syndromes with excessive grooming and reduced survival times. Also, investigations revealed hyperaldosteronism in SPRED2 KO mice with doubled serum aldosterone as compared with WT mice. Systematic investigation of contributing upstream hormone axes demonstrated, that hyperaldosteronism developed independently of an overactivated Renin-Angiotensin system as indicated by halved serum Ang II levels in KO mice. However, aldosterone synthase expression in the adrenal gland was substantially augmented. First indications for cardiac pathologies in SPRED KO mice resulted from initial cardiac tests of Ullrich et al., revealing enlarged hearts with elevated heart weight/body weight ratios, as well as increased stroke volumes in KO mice. To investigate whether the cardiac phenotype and the reduced survival time is a consequence of the genotype or secondary due to hyperaldosteronism, electrocardiograms, electrophysiological studies, both with arrhythmia analysis, as well as PSR-stainings, were performed with untreated mice, as well as animals after eplerenone treatment. Some ECG-parameters showed significant differences, for example QRS-interval was prolonged in KO-mice, as correlation for ventricular conduction time. Under isoproterenol stimulation, p-wave duration as well as PQ-interval revealed to be extended. These differences showed to be reduced due to eplerenone treatment, in case of PQ-time and QRS-interval after isoproterenol stimulation, even in significant dimension. Concerning the arrhythmia analysis in ECG and EPU, results showed a distinctly increased vulnerability for arrhythmias in KO-mice, which could be influenced with eplerenone treatment. EP studies revealed no significant differences regarding function of sinus and atrioventricular node, but, analogous to ECG-studies, significant more and severe arrhythmias could be detected in KO-mice, which could be clearly reduced with eplerone. By use of Picro-sirius red staining as a tool to appraise collagen fibers, a significant higher amount of collagen in heart slices of KO-mice could be proved, while treatment with eplerenone reduced fibrosis distinctly, both in WT and in KO-mice. In summary, manifold phenotypical characterizations of SPRED2 KO mice showed to be only partially result of the hyperaldosteronism and revealed only partial influence due to eplerenone treatment. KW - Spred-Proteine KW - Renin-Angiotensin-System KW - Aldosteronantagonist KW - Herzfunktion KW - MAP-Kinase KW - Gen-Knockout KW - Renin-Angiotensin-Aldosteron-System KW - heart KW - aldosterone Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166029 ER - TY - CHAP A1 - Werner, Rudolf A1 - Chen, Xinyu A1 - Lapa, Constantin A1 - Robinson, Simon A1 - Higuchi, Takahiro T1 - Intracellular behavior of the novel sympathetic nerve agent \(^{18}\)F-LMI1195 T2 - Journal of Nuclear Cardiology N2 - No abstract available. KW - Herz KW - PET KW - sympathetic nerve KW - autonomic nervous system KW - 18F-LMI1195 KW - positron emission tomography KW - heart KW - cardiac Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161137 SN - 1071-3581 N1 - This is a post-peer-review, pre-copyedit version of an article published in J Nucl Cardiol. ISSN: 1071-3581. Supplement (2017) Aug;24;4: 1461-1496. The final authenticated version is available online at: http://dx.doi.org/10.1007/s12350-017-0984-y VL - 24 IS - 4 Supplement (2017) Aug ER - TY - JOUR A1 - Van Steenbergen, Anne A1 - Balteau, Magali A1 - Ginion, Audrey A1 - Ferté, Laura A1 - Battault, Sylvain A1 - de Meester de Ravenstein, Christophe A1 - Balligand, Jean-Luc A1 - Daskalopoulos, Evangelos-Panagiotis A1 - Gilon, Patrick A1 - Despa, Florin A1 - Despa, Sanda A1 - Vanoverschelde, Jean-Louis A1 - Horman, Sandrine A1 - Koepsell, Hermann A1 - Berry, Gerard A1 - Hue, Louis A1 - Bertrand, Luc A1 - Beauloye, Christophe T1 - Sodium-myoinositol cotransporter-1, SMIT1, mediates the production of reactive oxygen species induced by hyperglycemia in the heart JF - Scientific Reports N2 - Hyperglycemia (HG) stimulates the production of reactive oxygen species in the heart through activation of NADPH oxidase 2 (NOX2). This production is independent of glucose metabolism but requires sodium/glucose cotransporters (SGLT). Seven SGLT isoforms (SGLT1 to 6 and sodium-myoinositol cotransporter-1, SMIT1) are known, although their expression and function in the heart remain elusive. We investigated these 7 isoforms and found that only SGLT1 and SMIT1 were expressed in mouse, rat and human hearts. In cardiomyocytes, galactose (transported through SGLT1) did not activate NOX2. Accordingly, SGLT1 deficiency did not prevent HG-induced NOX2 activation, ruling it out in the cellular response to HG. In contrast, myo-inositol (transported through SMIT1) reproduced the toxic effects of HG. SMIT1 overexpression exacerbated glucotoxicity and sensitized cardiomyocytes to HG, whereas its deletion prevented HG-induced NOX2 activation. In conclusion, our results show that heart SMIT1 senses HG and triggers NOX2 activation. This could participate in the redox signaling in hyperglycemic heart and contribute to the pathophysiology of diabetic cardiomyopathy. KW - hyperglycemia KW - Sodium-myoinositol cotransporter-1 (SMIT1) KW - glucose metabolism KW - heart KW - NADPH oxidase 2 (NOX2) KW - sodium/glucose cotransporters (SGLT) KW - cardiomyocytes Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-180891 VL - 7 ER - TY - JOUR A1 - Brodehl, Andreas A1 - Belke, Darrell D. A1 - Garnett, Lauren A1 - Martens, Kristina A1 - Abdelfatah, Nelly A1 - Rodriguez, Marcela A1 - Diao, Catherine A1 - Chen, Yong-Xiang A1 - Gordon, Paul M. K. A1 - Nygren, Anders A1 - Gerull, Brenda T1 - Transgenic mice overexpressing desmocollin-2 (DSC2) develop cardiomyopathy associated with myocardial inflammation and fibrotic remodeling JF - PLoS ONE N2 - Background Arrhythmogenic cardiomyopathy is an inherited heart muscle disorder leading to ventricular arrhythmias and heart failure, mainly as a result of mutations in cardiac desmosomal genes. Desmosomes are cell-cell junctions mediating adhesion of cardiomyocytes; however, the molecular and cellular mechanisms underlying the disease remain widely unknown. Desmocollin-2 is a desmosomal cadherin serving as an anchor molecule required to reconstitute homeostatic intercellular adhesion with desmoglein-2. Cardiac specific lack of desmoglein-2 leads to severe cardiomyopathy, whereas overexpression does not. In contrast, the corresponding data for desmocollin-2 are incomplete, in particular from the view of protein overexpression. Therefore, we developed a mouse model overexpressing desmocollin-2 to determine its potential contribution to cardiomyopathy and intercellular adhesion pathology. Methods and results We generated transgenic mice overexpressing DSC2 in cardiac myocytes. Transgenic mice developed a severe cardiac dysfunction over 5 to 13 weeks as indicated by 2D-echocardiography measurements. Corresponding histology and immunohistochemistry demonstrated fibrosis, necrosis and calcification which were mainly localized in patches near the epi- and endocardium of both ventricles. Expressions of endogenous desmosomal proteins were markedly reduced in fibrotic areas but appear to be unchanged in non-fibrotic areas. Furthermore, gene expression data indicate an early up-regulation of inflammatory and fibrotic remodeling pathways between 2 to 3.5 weeks of age. Conclusion Cardiac specific overexpression of desmocollin-2 induces necrosis, acute inflammation and patchy cardiac fibrotic remodeling leading to fulminant biventricular cardiomyopathy. KW - heart KW - mouse models KW - gene expression KW - fibrosis KW - inflammation KW - gene expression KW - genetically modified animals KW - cardiomyopathies KW - hyperexpression techniques Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171084 VL - 12 IS - 3 ER - TY - JOUR A1 - Kirschmer, Nadine A1 - Bandleon, Sandra A1 - von Ehrlich-Treuenstätt, Viktor A1 - Hartmann, Sonja A1 - Schaaf, Alice A1 - Lamprecht, Anna-Karina A1 - Miranda-Laferte, Erick A1 - Langsenlehner, Tanja A1 - Ritter, Oliver A1 - Eder, Petra T1 - TRPC4α and TRPC4β Similarly Affect Neonatal Cardiomyocyte Survival during Chronic GPCR Stimulation JF - PLoS ONE N2 - The Transient Receptor Potential Channel Subunit 4 (TRPC4) has been considered as a crucial Ca\(^{2+}\) component in cardiomyocytes promoting structural and functional remodeling in the course of pathological cardiac hypertrophy. TRPC4 assembles as homo or hetero-tetramer in the plasma membrane, allowing a non-selective Na\(^{+}\) and Ca\(^{2+}\) influx. Gαq protein-coupled receptor (GPCR) stimulation is known to increase TRPC4 channel activity and a TRPC4-mediated Ca\(^{2+}\) influx which has been regarded as ideal Ca\(^{2+}\) source for calcineurin and subsequent nuclear factor of activated T-cells (NFAT) activation. Functional properties of TRPC4 are also based on the expression of the TRPC4 splice variants TRPC4α and TRPC4β. Aim of the present study was to analyze cytosolic Ca\(^{2+}\) signals, signaling, hypertrophy and vitality of cardiomyocytes in dependence on the expression level of either TRPC4α or TRPC4β. The analysis of Ca\(^{2+}\) transients in neonatal rat cardiomyocytes (NRCs) showed that TRPC4α and TRPC4β affected Ca\(^{2+}\) cycling in beating cardiomyocytes with both splice variants inducing an elevation of the Ca\(^{2+}\) transient amplitude at baseline and TRPC4β increasing the Ca\(^{2+}\) peak during angiotensin II (Ang II) stimulation. NRCs infected with TRPC4β (Ad-C4β) also responded with a sustained Ca\(^{2+}\) influx when treated with Ang II under non-pacing conditions. Consistent with the Ca\(^{2+}\) data, NRCs infected with TRPC4α (Ad-C4α) showed an elevated calcineurin/NFAT activity and a baseline hypertrophic phenotype but did not further develop hypertrophy during chronic Ang II/phenylephrine stimulation. Down-regulation of endogenous TRPC4α reversed these effects, resulting in less hypertrophy of NRCs at baseline but a markedly increased hypertrophic enlargement after chronic agonist stimulation. Ad-C4β NRCs did not exhibit baseline calcineurin/NFAT activity or hypertrophy but responded with an increased calcineurin/NFAT activity after GPCR stimulation. However, this effect was not translated into an increased propensity towards hypertrophy but rather less hypertrophy during GPCR stimulation. Further analyses revealed that, although hypertrophy was preserved in Ad-C4α NRCs and even attenuated in Ad-C4β NRCs, cardiomyocytes had an increased apoptosis rate and thus were less viable after chronic GPCR stimulation. These findings suggest that TRPC4α and TRPC4β differentially affect Ca\(^{2+}\) signals, calcineurin/NFAT signaling and hypertrophy but similarly impair cardiomyocyte viability during GPCR stimulation. KW - Apoptosis KW - calcineurin signaling cascade KW - small interfering RNAs KW - G protein coupled receptors KW - hyperexpression techniques KW - heart KW - adenoviruses KW - cardiac pacing Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178539 VL - 11 IS - 12 ER - TY - JOUR A1 - Gyberg, Viveca A1 - De Bacquer, Dirk A1 - De Backer, Guy A1 - Jennings, Catriona A1 - Kotseva, Kornelia A1 - Mellbin, Linda A1 - Schnell, Oliver A1 - Tuomilehto, Jaakko A1 - Wood, David A1 - Ryden, Lars A1 - Amouyel, Philippe A1 - Bruthans, Jan A1 - Conde, Almudena Castro A1 - Cifkova, Renata A1 - Deckers, Jaap W. A1 - De Sutter, Johan A1 - Dilic, Mirza A1 - Dolzhenko, Maryna A1 - Erglis, Andrejs A1 - Fras, Zlatko A1 - Gaita, Dan A1 - Gotcheva, Nina A1 - Goudevenos, John A1 - Heuschmann, Peter A1 - Laucevicius, Aleksandras A1 - Lehto, Seppo A1 - Lovic, Dragan A1 - Milicic, Davor A1 - Moore, David A1 - Nicolaides, Evagoras A1 - Oganov, Raphae A1 - Pajak, Andrzej A1 - Pogosova, Nana A1 - Reiner, Zeljko A1 - Stagmo, Martin A1 - Störk, Stefan A1 - Tokgözoglu, Lale A1 - Vulic, Dusko T1 - Patients with coronary artery disease and diabetes need improved management: a report from the EUROASPIRE IV survey: a registry from the EuroObservational Research Programme of the European Society of Cardiology JF - Cardiovascular Diabetology N2 - Background: In order to influence every day clinical practice professional organisations issue management guidelines. Cross-sectional surveys are used to evaluate the implementation of such guidelines. The present survey investigated screening for glucose perturbations in people with coronary artery disease and compared patients with known and newly detected type 2 diabetes with those without diabetes in terms of their life-style and pharmacological risk factor management in relation to contemporary European guidelines. Methods: A total of 6187 patients (18-80 years) with coronary artery disease and known glycaemic status based on a self reported history of diabetes (previously known diabetes) or the results of an oral glucose tolerance test and HbA1c (no diabetes or newly diagnosed diabetes) were investigated in EUROASPIRE IV including patients in 24 European countries 2012-2013. The patients were interviewed and investigated in order to enable a comparison between their actual risk factor control with that recommended in current European management guidelines and the outcome in previously conducted surveys. Results: A total of 2846 (46 %) patients had no diabetes, 1158 (19 %) newly diagnosed diabetes and 2183 (35 %) previously known diabetes. The combined use of all four cardioprotective drugs in these groups was 53, 55 and 60 %, respectively. A blood pressure target of <140/90 mmHg was achieved in 68, 61, 54 % and a LDL-cholesterol target of <1.8 mmol/L in 16, 18 and 28 %. Patients with newly diagnosed and previously known diabetes reached an HbA1c <7.0 % (53 mmol/mol) in 95 and 53 % and 11 % of those with previously known diabetes had an HbA1c >9.0 % (>75 mmol/mol). Of the patients with diabetes 69 % reported on low physical activity. The proportion of patients participating in cardiac rehabilitation programmes was low (approximate to 40 %) and only 27 % of those with diabetes had attended diabetes schools. Compared with data from previous surveys the use of cardioprotective drugs had increased and more patients were achieving the risk factor treatment targets. Conclusions: Despite advances in patient management there is further potential to improve both the detection and management of patients with diabetes and coronary artery disease. KW - heart KW - glycaemic control KW - cardiovascular diseases KW - myocardial infarction KW - glucose control KW - blood-glucose KW - risk factors KW - follow-up KW - mellitus KW - mortality KW - guidelines KW - coronary artery disease KW - type 2 diabetes KW - secondary prevention KW - management KW - guideline adherence KW - blood pressure KW - blood lipids Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-141358 VL - 14 IS - 133 ER - TY - JOUR A1 - Boivin, Valérie A1 - Beyersdorf, Niklas A1 - Palm, Dieter A1 - Nikolaev, Viacheslav O. A1 - Schlipp, Angela A1 - Müller, Justus A1 - Schmidt, Doris A1 - Kocoski, Vladimir A1 - Kerkau, Thomas A1 - Hünig, Thomas A1 - Ertl, Georg A1 - Lohse, Martin J. A1 - Jahns, Roland T1 - Novel Receptor-Derived Cyclopeptides to Treat Heart Failure Caused by \(Anti-β_1-Adrenoceptor\) Antibodies in a Human-Analogous Rat Model JF - PLoS One N2 - Despite recent therapeutic advances the prognosis of heart failure remains poor. Recent research suggests that heart failure is a heterogeneous syndrome and that many patients have stimulating auto-antibodies directed against the second extracellular loop of the \(β_1\) adrenergic receptor \((β_1EC2)\). In a human-analogous rat model such antibodies cause myocyte damage and heart failure. Here we used this model to test a novel antibody-directed strategy aiming to prevent and/or treat antibody-induced cardiomyopathy. To generate heart failure, we immunised n = 76/114 rats with a fusion protein containing the human β1EC2 (amino-acids 195–225) every 4 weeks; n = 38/114 rats were control-injected with 0.9% NaCl. Intravenous application of a novel cyclic peptide mimicking \(β_1EC2\) (\(β_1EC2-CP\), 1.0 mg/kg every 4 weeks) or administration of the \(β_1-blocker\) bisoprolol (15 mg/kg/day orally) was initiated either 6 weeks (cardiac function still normal, prevention-study, n = 24 (16 treated vs. 8 untreated)) or 8.5 months after the 1st immunisation (onset of cardiomyopathy, therapy-study, n = 52 (40 treated vs. 12 untreated)); n = 8/52 rats from the therapy-study received \(β_1EC2-CP/bisoprolol\) co-treatment. We found that \(β_1EC2-CP\) prevented and (alone or as add-on drug) treated antibody-induced cardiac damage in the rat, and that its efficacy was superior to mono-treatment with bisoprolol, a standard drug in heart failure. While bisoprolol mono-therapy was able to stop disease-progression, \(β_1EC2-CP\) mono-therapy -or as an add-on to bisoprolol- almost fully reversed antibody-induced cardiac damage. The cyclo¬peptide acted both by scavenging free \(anti-β_1EC2-antibodies\) and by targeting \(β_1EC2\)-specific memory B-cells involved in antibody-production. Our model provides the basis for the clinical translation of a novel double-acting therapeutic strategy that scavenges harmful \(anti-β_1EC2-antibodies\) and also selectively depletes memory B-cells involved in the production of such antibodies. Treatment with immuno-modulating cyclopeptides alone or as an add-on to \(β_1\)-blockade represents a promising new therapeutic option in immune-mediated heart failure. KW - memory B cells KW - antibodies KW - T cells KW - B cells KW - heart KW - heart failure KW - kidneys KW - enzyme-linked immunoassays Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126028 VL - 10 IS - 2 ER - TY - JOUR A1 - Macedo, Robson A1 - Javadi, Som Mehrbod A1 - Higuchi, Takahiro A1 - Ferreira de Carvalho, Marilia Daniela A1 - Lima Paiva Medeiros, Vanessa de Fátima A1 - Azevedo, Ítalo Medeiros A1 - Lima, Francisco Pignataro A1 - Medeiros, Aldo Cunha T1 - Heart and systemic effects of statin pretreatment in a rat model of abdominal sepsis. Assessment by Tc\(^{99m}\)-sestamibi biodistribition JF - Acta Cirúrgica Brasileira N2 - PURPOSE: To evaluate the heart and the Tc-99m-sestamibi biodistribution after statin pretreatment in a rat model of abdominal sepsis. METHODS: Twenty-four Wistar rats were randomly distributed into four groups (n=6 per group): 1) sepsis with simvastatin treatment, 2) sepsis with vehicle, 3) sham control with simvastatin and 4) sham control with vehicle. 24 hours after cecal ligation and puncture rats received 1.0MBq of Tc-99m-sestamibi i.v. 30min after, animals were euthanized for ex-vivo tissue counting and myocardium histological analysis. RESULTS: Myocardial histologic alterations were not detected 24 hours post-sepsis. There was significantly increased cardiac Tc-99m-sestamibi activity in the sepsis group with simvastatin treatment (1.9\(\pm\)0.3%ID/g, p<0.001) in comparison to the sepsis group+vehicle (1.0\(\pm\)0.2% ID/g), control sham group+ simvastatin (1.2\(\pm\)0.3% ID/g) and control sham group (1.3\(\pm\)0.2% ID/g). Significant Tc-99m-sestamibi activity in liver, kidney and lungs was also detected in the sepsis group treated with simvastatinin comparison to the other groups. CONCLUSIONS: Statin treatment altered the biodistribution of Tc-99m-sestamibi with increased cardiac and solid organ activity in rats with abdominal sepsis, while no impact on controls. Increased myocardial tracer activity may be a result of a possible protection effect due to increased tissue perfusion mediated by statins. KW - P-glycoprotein expression KW - mechanisms retention KW - Simvastatin KW - Technetium Tc 99m Sestamibi Rats KW - heart KW - inflammation KW - sepsis Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151887 VL - 30 IS - 6 SP - 388 EP - 393 ER - TY - JOUR A1 - Brand, Susanne A1 - Amann, Kerstin A1 - Mandel, Philipp A1 - Zimnol, Anna A1 - Schupp, Nicole T1 - Oxidative DNA Damage in Kidneys and Heart of Hypertensive Mice Is Prevented by Blocking Angiotensin II and Aldosterone Receptors JF - PLOS ONE N2 - INTRODUCTION: Recently, we could show that angiotensin II, the reactive peptide of the blood pressure-regulating renin-angiotensin-aldosterone-system, causes the formation of reactive oxygen species and DNA damage in kidneys and hearts of hypertensive mice. To further investigate on the one hand the mechanism of DNA damage caused by angiotensin II, and on the other hand possible intervention strategies against end-organ damage, the effects of substances interfering with the renin-angiotensin-aldosterone-system on angiotensin II-induced genomic damage were studied. METHODS: In C57BL/6-mice, hypertension was induced by infusion of 600 ng/kg • min angiotensin II. The animals were additionally treated with the angiotensin II type 1 receptor blocker candesartan, the mineralocorticoid receptor blocker eplerenone and the antioxidant tempol. DNA damage and the activation of transcription factors were studied by immunohistochemistry and protein expression analysis. RESULTS: Administration of angiotensin II led to a significant increase of blood pressure, decreased only by candesartan. In kidneys and hearts of angiotensin II-treated animals, significant oxidative stress could be detected (1.5-fold over control). The redox-sensitive transcription factors Nrf2 and NF-κB were activated in the kidney by angiotensin II-treatment (4- and 3-fold over control, respectively) and reduced by all interventions. In kidneys and hearts an increase of DNA damage (3- and 2-fold over control, respectively) and of DNA repair (3-fold over control) was found. These effects were ameliorated by all interventions in both organs. Consistently, candesartan and tempol were more effective than eplerenone. CONCLUSION: Angiotensin II-induced DNA damage is caused by angiotensin II type 1 receptor-mediated formation of oxidative stress in vivo. The angiotensin II-mediated physiological increase of aldosterone adds to the DNA-damaging effects. Blocking angiotensin II and mineralocorticoid receptors therefore has beneficial effects on end-organ damage independent of blood pressure normalization. KW - aldosterone KW - oxidative stress KW - transcription factors KW - kidneys KW - heart KW - hypertension KW - DNA damage KW - blood pressure Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-118011 SN - 1932-6203 VL - 9 IS - 12 ER - TY - JOUR A1 - Haring, Bernhard A1 - Wyler von Ballmoos, Moritz C. A1 - Appel, Lawrence J. A1 - Sacks, Frank M. T1 - Healthy Dietary Interventions and Lipoprotein (a) Plasma Levels: Results from the Omni Heart Trial N2 - Background: Increased lipoprotein(a) [Lp(a)] levels are associated with atherosclerotic cardiovascular disease. Studies of dietary interventions on changes in Lp(a) are sparse. We aimed to compare the effects of three healthy dietary interventions differing in macronutrient content on Lp(a) concentration. Methods: Secondary analysis of a randomized, 3-period crossover feeding study including 155 (89 blacks; 66 whites) individuals. Participants were given DASHtype healthy diets rich in carbohydrates [Carb], in protein [Prot] or in unsaturated fat [Unsat Fat] for 6 weeks each. Plasma Lp(a) concentration was assessed at baseline and after each diet. Results: Compared to baseline, all interventional diets increased mean Lp(a) by 2 to 5 mg/dl. Unsat Fat increased Lp(a) less than Prot with a difference of 1.0 mg/dl (95% CI, -0.5, 2.5; p=0.196) in whites and 3.7 mg/dl (95% CI, 2.4, 5.0; p<0.001) in blacks (p-value between races=0.008); Unsat Fat increased Lp(a) less than Carb with a difference of 20.6 mg/dl, 95% CI, -2.1, 0.9; p=0.441) in whites and 21.5 mg/dl (95% CI, -0.2, -2.8; p=0.021) in blacks (p-value between races=0.354). Prot increased Lp(a) more than Carb with a difference of 0.4 mg/dl (95% CI, -1.1, 1.9; p=0.597) in whites and 2.2 mg/dl (95%CI, 0.9, 3.5; p=0.001) in blacks (p-value between races=0.082). Conclusion: Diets high in unsaturated fat increased Lp(a) levels less than diets rich in carbohydrate or protein with greater changes in blacks than whites. Our results suggest that substitutions with dietary mono- and polyunsaturated fatty acids in healthy diets may be preferable over protein or carbohydrates with regards to Lp(a). KW - diet KW - carbohydrates KW - blood plasma KW - heart KW - food consumption KW - cholesterol KW - fatty acids KW - plasma proteins Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-111005 ER - TY - JOUR A1 - Pachel, Christina A1 - Mathes, Denise A1 - Bayer, Barbara A1 - Dienesch, Charlotte A1 - Wangorsch, Gaby A1 - Heitzmann, Wolfram A1 - Lang, Isabell A1 - Ardehali, Hossein A1 - Ertl, Georg A1 - Dandekar, Thomas A1 - Wajant, Harald A1 - Frantz, Stefan T1 - Exogenous Administration of a Recombinant Variant of TWEAK Impairs Healing after Myocardial Infarction by Aggravation of Inflammation JF - PLoS ONE N2 - Background: Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factorinducible 14 (Fn14) are upregulated after myocardial infarction (MI) in both humans and mice. They modulate inflammation and the extracellular matrix, and could therefore be important for healing and remodeling after MI. However, the function of TWEAK after MI remains poorly defined. Methods and results: Following ligation of the left coronary artery, mice were injected twice per week with a recombinant human serum albumin conjugated variant of TWEAK (HSA-Flag-TWEAK), mimicking the activity of soluble TWEAK. Treatment with HSA-Flag-TWEAK resulted in significantly increased mortality in comparison to the placebo group due to myocardial rupture. Infarct size, extracellular matrix remodeling, and apoptosis rates were not different after MI. However, HSA-Flag-TWEAK treatment increased infiltration of proinflammatory cells into the myocardium. Accordingly, depletion of neutrophils prevented cardiac ruptures without modulating all-cause mortality. Conclusion: Treatment of mice with HSA-Flag-TWEAK induces myocardial healing defects after experimental MI. This is mediated by an exaggerated neutrophil infiltration into the myocardium. KW - apoptosis KW - myocardial infarction KW - neutrophils KW - cytokines KW - inflammation KW - myocardium KW - heart KW - extracellular matrix Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-129889 VL - 8 IS - 11 ER - TY - JOUR A1 - Benz, Peter M. A1 - Merkel, Carla J. A1 - Offner, Kristin A1 - Abeßer, Marco A1 - Ullrich, Melanie A1 - Fischer, Tobias A1 - Bayer, Barbara A1 - Wagner, Helga A1 - Gambaryan, Stepan A1 - Ursitti, Jeanine A. A1 - Adham, Ibrahim M. A1 - Linke, Wolfgang A. A1 - Feller, Stephan M. A1 - Fleming, Ingrid A1 - Renné, Thomas A1 - Frantz, Stefan A1 - Unger, Andreas A1 - Schuh, Kai T1 - Mena/VASP and alphaII-Spectrin complexes regulate cytoplasmic actin networks in cardiomyocytes and protect from conduction abnormalities and dilated cardiomyopathy JF - Cell Communication and Signaling N2 - Background: In the heart, cytoplasmic actin networks are thought to have important roles in mechanical support, myofibrillogenesis, and ion channel function. However, subcellular localization of cytoplasmic actin isoforms and proteins involved in the modulation of the cytoplasmic actin networks are elusive. Mena and VASP are important regulators of actin dynamics. Due to the lethal phenotype of mice with combined deficiency in Mena and VASP, however, distinct cardiac roles of the proteins remain speculative. In the present study, we analyzed the physiological functions of Mena and VASP in the heart and also investigated the role of the proteins in the organization of cytoplasmic actin networks. Results: We generated a mouse model, which simultaneously lacks Mena and VASP in the heart. Mena/VASP double-deficiency induced dilated cardiomyopathy and conduction abnormalities. In wild-type mice, Mena and VASP specifically interacted with a distinct αII-Spectrin splice variant (SH3i), which is in cardiomyocytes exclusively localized at Z- and intercalated discs. At Z- and intercalated discs, Mena and β-actin localized to the edges of the sarcomeres, where the thin filaments are anchored. In Mena/VASP double-deficient mice, β-actin networks were disrupted and the integrity of Z- and intercalated discs was markedly impaired. Conclusions: Together, our data suggest that Mena, VASP, and αII-Spectrin assemble cardiac multi-protein complexes, which regulate cytoplasmic actin networks. Conversely, Mena/VASP deficiency results in disrupted β-actin assembly, Z- and intercalated disc malformation, and induces dilated cardiomyopathy and conduction abnormalities. KW - Mena/VASP KW - dilated cardiomyopathy KW - actin KW - heart KW - spectrin Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128760 VL - 11 IS - 56 ER - TY - JOUR A1 - Jazbutyte, Virginija A1 - Stumpner, Jan A1 - Redel, Andreas A1 - Lorenzen, Johan M. A1 - Roewer, Norbert A1 - Thum, Thomas A1 - Kehl, Franz T1 - Aromatase Inhibition Attenuates Desflurane-Induced Preconditioning against Acute Myocardial Infarction in Male Mouse Heart In Vivo JF - PLoS One N2 - The volatile anesthetic desflurane (DES) effectively reduces cardiac infarct size following experimental ischemia/reperfusion injury in the mouse heart. We hypothesized that endogenous estrogens play a role as mediators of desflurane-induced preconditioning against myocardial infarction. In this study, we tested the hypothesis that desflurane effects local estrogen synthesis by modulating enzyme aromatase expression and activity in the mouse heart. Aromatase metabolizes testosterone to 17b- estradiol (E2) and thereby significantly contributes to local estrogen synthesis. We tested aromatase effects in acute myocardial infarction model in male mice. The animals were randomized and subjected to four groups which were pre-treated with the selective aromatase inhibitor anastrozole (A group) and DES alone (DES group) or in combination (A+DES group) for 15 minutes prior to surgical intervention whereas the control group received 0.9% NaCl (CON group). All animals were subjected to 45 minutes ischemia following 180 minutes reperfusion. Anastrozole blocked DES induced preconditioning and increased infarct size compared to DES alone (37.94615.5% vs. 17.163.62%) without affecting area at risk and systemic hemodynamic parameters following ischemia/reperfusion. Protein localization studies revealed that aromatase was abundant in the murine cardiovascular system with the highest expression levels in endothelial and smooth muscle cells. Desflurane application at pharmacological concentrations efficiently upregulated aromatase expression in vivo and in vitro. We conclude that desflurane efficiently regulates aromatase expression and activity which might lead to increased local estrogen synthesis and thus preserve cellular integrity and reduce cardiac damage in an acute myocardial infarction model. KW - smooth muscle cells KW - estrogens KW - heart KW - anesthetics KW - immunostaining KW - endothelial cells KW - gene expression KW - myocardial infarction Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-151258 VL - 7 IS - 8 ER - TY - THES A1 - Bönhof, Leoni Jacobea T1 - Herzinfarkt-scheinoperierte Ratten vs. gesunde Ratten: Ein Vergleich in der Cine-Herzmagnetresonanztomografie T1 - Heart infarct Sham-operated rats vs. healthy rats - A comparison in Cine Magnetic resonance imaging N2 - In der vorliegenden Arbeit wurde überprüft, ob sich sham-operierte Versuchsratten und gesunde Vergleichsratten in via Cine-Herz-MRT zu erfassenden Parametern signifkant unterscheiden. Hierzu wurden an einem Bruker 7 Tesla-Magnetresonanztomografen drei verschiedene Tiergruppen à 6 Tiere untersucht. Der erste Vergleich fand statt zwischen der gesunden Vergleichsgruppe und einer ähnlich schweren Shamtiergruppe, die sich in der 8. postoperativen Woche befand. Nachdem hier keinerlei signifikante Unterschiede zwischen den beiden Gruppen festzustellen waren, wurde der Vergleich ausgeweitet: Die Shamgruppe wurde zu einem frühen postoperativen Zeitpunkt (7-14 Tage postoperativ) ein zweites Mal mit der gesunden Gruppe verglichen. N2 - The aim of this study was to test whether heart infarction sham operated rats were disparable from healthy rats by parameters captured by Cine MRI, gold standard of cardiac imaging. Therefore three groups of animals were examined, right and left ventricular myocardial parameters were determined and a comprehensive comparison of cardiac parameters was done. The first comparison was drawn between a healthy animal group and sham operated animals of nearly similar weight and age, 8 weeks after surgical procedure. Furthermore, we compared the same healthy animals’ group with remarkably younger sham animals quite shortly (in the 2nd week) after surgery. KW - Herz KW - MRT KW - Cine KW - Ratte KW - Sham KW - Myokard KW - Infarkt KW - Cine KW - MRI KW - rats KW - heart KW - infarction Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-71520 ER - TY - THES A1 - Link, Martin Benedikt [jetzt: Sittl, Martin] T1 - Die Rolle der neuronalen Stickstoffmonoxid-Synthase im Herzen T1 - The role of neuronal nitric oxide synthase in the heart N2 - Diese Arbeit zeigt, dass die spezifische Inhibition der neuronalen NO-Synthase zu einer Reduktion der myokardialen Ökonomie führt. Umgekehrt lässt sich postulieren, dass die Produktion von Stickstoffmonoxid durch die nNOS eine gesteigerte Effizienz des Herzmuskelgewebes bewirkt. N2 - This study shows that specific inhibition of neuronal NO synthase leads to a reduction of myokardial efficiency. Vice versa one can postulate that the production of nitric oxide by nNOS improves the efficiency of the myokardium. KW - Stickstoffmonoxid-Synthase KW - Herzmuskel KW - nNOS KW - neuronal nitric oxide synthase KW - heart KW - nNOS Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69252 ER - TY - THES A1 - Kirchmaier, Bettina Carmen T1 - Characterization of the Popeye domain containing gene family in zebrafish T1 - Charakterisierung der Popeye domain containing Genfamilie im Zebrafisch N2 - The Popeye domain containing (Popdc) gene family of membrane proteins is predominantly expressed in striated and smooth muscle tissues and has been shown to act as novel cAMP-binding proteins. In mice, loss of Popdc1 and Popdc2, respectively, affects sinus node function in the postnatal heart in an age and stress-dependent manner. In this thesis, I examined gene expression pattern and function of the Popdc gene family during zebrafish development with an emphasis on popdc2. Expression of the zebrafish popdc2 was exclusively present in cardiac and skeletal muscle during cardiac development, whereas popdc3 was expressed in striated muscle tissue and in distinct regions of the brain. In order to study the function of these genes, an antisense morpholino-based knockdown approach was used. Knockdown of popdc2 resulted in aberrant development of facial and tail musculature. In the heart, popdc2 morphants displayed irregular ventricular contractions with 2:1 and 3:1 ventricular pauses. Recordings of calcium transients using a transgenic indicator line Tg(cmlc2:gCaMP)s878 and selective plane illumination microscopy (SPIM) revealed the presence of an atrioventricular (AV) block in popdc2 morphants as well as a complete heart block. Interestingly, preliminary data revealed that popdc3 morphants developed a similar phenotype. In order to find a morphological correlate for the observed AV conduction defect, I studied the structure of the AV canal in popdc2 morphants using confocal analysis of hearts of the transgenic line Tg(cmlc2:eGFP-ras)s883, which outlines individual cardiac myocytes with the help of membrane-localized GFP. However, no evidence for morphological alterations was obtained. To ensure that the observed arrhythmia phenotype in the popdc2 morphant was based on a myocardial defect and not caused by defective valve development, live imaging was performed revealing properly formed valves. Thus, in agreement with the data obtained in knockout mice, popdc2 and popdc3 genes in zebrafish are involved in the regulation of cardiac electrical activity. However, both genes are not required for cardiac pacemaking, but they play essential roles in AV conduction. In order to elucidate the biological importance of cAMP-binding, wild type Popdc1 as well as mutants with a significant reduction in binding affinity for cAMP in vitro were overexpressed in zebrafish embryos. Expression of wild type Popdc1 led to a cardiac insufficiency phenotype characterized by pericardial edema and venous blood retention. Strikingly, the ability of the Popdc1 mutants to induce a cardiac phenotype correlated with the binding affinity for cAMP. These data suggest that cAMP-binding represents an important biological property of the Popdc protein family. N2 - Die Popeye domain containing (Popdc) Gene kodieren für eine Familie von Membranproteinen, die vorwiegend in der gestreiften und glatten Muskulatur exprimiert werden und in der Lage sind cAMP zu binden. In Mäusen resultiert der Verlust von Popdc1 oder Popdc2 in einer stressinduzierten Sinusknotendysfunktion, die sich altersabhängig entwickelt. In meiner Dissertation habe ich das Expressionsmuster und die Funktion der Popdc Genfamilie mit Schwerpunkt auf dem popdc2-Gen im Zebrafisch untersucht. Das popdc2-Gen im Zebrafisch wurde ausschließlich in der Herz- und Skelettmuskulatur exprimiert, während popdc3 sowohl in der quergestreiften Muskulatur, als auch im Gehirn exprimiert wurde. Um die Funktion dieser Gene zu untersuchen, wurde die Prozessierung der prä-mRNA mit Hilfe von Morpholinos unterdrückt, die gegen die Spleißdonor bzw. -akzeptorsequenzen von popdc2 und popdc3 gerichtet waren. Das Fehlen von popdc2 im Zebrafisch resultierte in einer Fehlentwicklung der Gesichts- und Schwanzmuskulatur. Im Herzen der popdc2-Morphanten waren ventrikuläre Überleitungsstörungen mit einem 2:1 oder 3:1 Rhythmus zu beobachten. Analysen der Calciumfreisetzung mittels SPIM (selective plane illumination microscopy) in der transgenen Zebrafischlinie Tg(cmlc2:gCaMP)s878, die einen fluoreszierenden Calciumindikator exprimiert, zeigten in den popdc2-Morphanten einen AV-Block bis hin zum kompletten Herzblock. Interessanterweise ergaben vorläufige Analysen in popdc3-Morphanten einen ähnlichen Phänotyp. Um eine mögliche morphologische Ursache der beobachteten AV-Überleitungsstörung zu finden, habe ich die Struktur des AV-Kanals von popdc2-Morphanten mit Hilfe der transgenen Zebrafischlinie Tg(cmlc2:eGFP-rass883) und konfokaler Mikroskopie untersucht. Allerdings konnte ich kein Anzeichen für morphologische Veränderungen erkennen. Um sicherzugehen, dass der beobachtete Rhythmusphänotyp der popdc2-Morphanten nicht auf einer myokardialen Störung beruht oder auf einem Defekt bei der Klappenentwicklung, wurden zusätzlich Lebendaufnahmen angefertigt, die zeigten, dass die Klappen normal entwickelt waren. In Übereinstimmung mit den Daten aus den Knockout-Mäusen haben die popdc2- und popdc3-Gene auch im Zebrafisch eine wichtige Funktion bei der elektrischen Reizleitung im Herzen. Allerdings sind die beiden Gene für die Erregungsbildung im Sinusknoten nicht essentiell, sondern werden für die Signalübertragung im AV-Kanal benötigt. Um die biologische Signifikanz der cAMP-Bindung zu untersuchen, wurden Wildtyp-Popdc1 und Punktmutanten, die eine Reduktion in der cAMP-Bindung aufweisen, nach RNA-Injektion in Zebrafischembryonen überexprimiert. Die Injektion von Wildtyp-Popdc1 induzierte eine embryonale Herzinsuffizienz, die durch perikardiales Ödem und venösen Blutstau charakterisiert war. Die Fähigkeit der Popdc1-Punktmutanten, einen Herzphänotyp nach Überexpression zu induzieren, war direkt korreliert mit der Bindungsaffinität für cAMP. Diese Daten lassen den Schluss zu, dass die Fähigkeit der cAMP-Bindung eine wichtige biologische Eigenschaft der Popdc-Proteinfamilie darstellt. KW - Zebrabärbling KW - Genexpression KW - Herzmuskel KW - Herz KW - Popdc Genfamilie KW - heart KW - popdc gene family Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-49413 ER -