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37 results on '"Lehnart, S."'

7. A protocol for registration and correction of multicolour STED superresolution images

Author

Hebisch, E., Wagner, E., Westphal, V., Sieber, J., and Lehnart, S.

Abstract

Multicolour fluorescence imaging by STimulated Emission Depletion (STED) superresolution microscopy with doughnut-shaped STED laser beams based on different wavelengths for each colour channel requires precise image registration. This is especially important when STED imaging is used for colocalisation studies of two or more native proteins in biological specimens to analyse nanometric subcellular spatial arrangements. We developed a robust postprocessing image registration protocol, with the aim to verify and ultimately optimise multicolour STED image quality. Importantly, this protocol will support any subsequent quantitative localisation analysis at nanometric scales. Henceforth, using an approach that registers each colour channel present during STED imaging individually, this protocol reliably corrects for optical aberrations and inadvertent sample drift. To achieve the latter goal, the protocol combines the experimental sample information, from corresponding STED and confocal images using the same optical beam path and setup, with that of an independent calibration sample. As a result, image registration is based on a strategy that maximises the cross-correlation between sequentially acquired images of the experimental sample, which are strategically combined by the protocol. We demonstrate the general applicability of the image registration protocol by co-staining of the ryanodine receptor calcium release channel in primary mouse cardiomyocytes. To validate this new approach, we identify user-friendly criteria, which - if fulfilled - support optimal image registration. In summary, we introduce a new method for image registration and rationally based postprocessing steps through a highly standardised protocol for multicolour STED imaging, which directly supports the reproducibility of protein co-localisation analyses. Although the reference protocol is discussed exemplarily for two-colour STED imaging, it can be readily expanded to three or more colours and STED channels.

Published
2017

10. P1223Prediction model for shock risk and mortality in ICD patients

Author

Bergau, L, primary, Willems, R, additional, Tuinenburg, A, additional, Vos, M A, additional, Flevari, P, additional, Luethje, L, additional, Fischer, T H, additional, Vandenberk, B, additional, Sprenkeler, D, additional, Roever, C, additional, Hasenfuss, G, additional, Lehnart, S E, additional, Friede, T, additional, and Zabel, M, additional

Published
2018
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11. Optogenetic light crafting tools for the control of cardiac arrhythmias

Author

Richter, C., Christoph, J., Lehnart, S., and Luther, S.

Abstract

The control of spatiotemporal dynamics in biological systems is a fundamental problem in nonlinear sciences and has important applications in engineering and medicine. Optogenetic tools combined with advanced optical technologies provide unique opportunities to develop and validate novel approaches to control spatiotemporal complexity in neuronal and cardiac systems. Understanding of the mechanisms and instabilities underlying the onset, perpetuation, and control of cardiac arrhythmias will enable the development and translation of novel therapeutic approaches. Here we describe in detail the preparation and optical mapping of transgenic channelrhodopsin-2 (ChR2) mouse hearts, cardiac cell cultures, and the optical setup for photostimulation using digital light processing.

Published
2016

13. Preservation of myocardial function after adenoviral gene transfer in isolated myocardium

Author

LEHNART, S. E., JANSSEN, P. M. L., FRANZ, W. M., DONAHUE, J. K., LAWRENCE, J. H., MARBAN, E., PRESTLE, J., and HASENFUSS, G.

Subjects
Adenoviruses -- Research, Rabbits -- Research, Biological sciences
Abstract

Preservation of myocardial function after adenoviral gene transfer in isolated myocardium. Am J Physiol Heart Circ Physiol 279: H986-H991, 2000.--Adenoviral gene transfer to the heart represents a promising model for structure-function analyses. Rabbit hearts were subjected to an ex vivo perfusion protocol that achieves gene transfer in [is greater than] 90% of cardiac myocytes. Contractile function of isolated myocardial preparations of these hearts was then observed for 2 days in a recently developed trabecula culture system. In sham-infected hearts, the initial developed force ([F.sub.init]) (15.6 [+ or -] 3.7 mN/[mm.sup.2]; n = 12) did not change significantly after 48 h (17.0 [+ or -] 1.9 mN/[mm.sup.2]; P = 0.46). In adenovirus-infected preparations, [F.sub.init] (14.3 [+ or -] 1.8 mN/[mm.sup.2]; n = 21) did not significantly differ from the control (P = 0.75) and was unchanged after 48 h (15.3 [+ or -] 2.5 mN/[mm.sup.2]; P = 0.93). After 2 days of continuous contractions, we observed homogenous and high-level expression of the reporter genes LacZ coding for [Beta]-galactosidase and Luc coding for firefly luciferase. Luciferase activity increased more than 2,500-fold from background levels of 8.7 x [10.sup.3] [+ or -] 5.0 x [10.sup.3] relative light units (RLU)/mg protein (from hearts transfected with promotorless adenovirus with luciferase transgene construct AdNULLLuc, n = 5) to 23.4 x [10.sup.6] [+ or -] 11.1 x [10.sup.6] RLU/mg protein (from hearts tranfected with adenovirus with Rous sarcoma virus promotor and luciferase transgene construct AdRSVLuc, n = 5) in infected myocardial preparations (P [is less than] 0.005). Our results demonstrate a new ex vivo approach to achieve homogenous and high-level expression of recombinant adenoviral genes in contracting myocardium without adverse functional effects. adenovirus; trabecula; rabbit

Published
2000

17. Best Basic Science abstract

Author

Wagner, E., primary, Kohl, T., additional, Tuan, H. T. M., additional, Westphal, V., additional, Parlitz, U., additional, Luther, S., additional, Hell, S. W., additional, Jafri, M. S., additional, Lederer, W. J., additional, and Lehnart, S. E., additional

Published
2013
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18. Saturday, 17 July 2010

Author

Dimova, I., primary, Hlushchuk, R., additional, Makanya, A., additional, Djonov, V., additional, Theurl, M., additional, Schgoer, W., additional, Albrecht, K., additional, Beer, A., additional, Patsch, J. R., additional, Schratzberger, P., additional, Mahata, S., additional, Kirchmair, R., additional, Didie, M., additional, Christalla, P., additional, Rau, T., additional, Eschenhagen, T., additional, Schumacher, U., additional, Lin, Q., additional, Zenke, M., additional, Zimmmermann, W., additional, Hoch, M., additional, Fischer, P., additional, Stapel, B., additional, Missol-Kolka, E., additional, Erschow, S., additional, Scherr, M., additional, Drexler, H., additional, Hilfiker-Kleiner, D., additional, Diebold, I., additional, Petry, A., additional, Kennel, P., additional, Djordjevic, T., additional, Hess, J., additional, Goerlach, A., additional, Castellano, J., additional, Aledo, R., additional, Sendra, J., additional, Costales, P., additional, Badimon, L., additional, Llorente-Cortes, V., additional, Dworatzek, E., additional, Mahmoodzadeh, S., additional, Regitz-Zagrosek, V., additional, Posa, A., additional, Varga, C., additional, Berko, A., additional, Veszelka, M., additional, Szablics, P., additional, Vari, B., additional, Pavo, I., additional, Laszlo, F., additional, Brandenburger, M., additional, Wenzel, J., additional, Bogdan, R., additional, Richardt, D., additional, Reppel, M., additional, Hescheler, J., additional, Terlau, H., additional, Dendorfer, A., additional, Heijman, J., additional, Rudy, Y., additional, Westra, R., additional, Volders, P., additional, Rasmusson, R., additional, Bondarenko, V., additional, Ertas Gokhan, M. D., additional, Ural Ertan, M. D., additional, Karaoz Erdal, P. H. D., additional, Aksoy Ayca, P. H. D., additional, Kilic Teoman, M. D., additional, Kozdag Guliz, M. D., additional, Vural Ahmet, M. D., additional, Ural Dilek, M. D., additional, Poulet, C., additional, Christ, T., additional, Wettwer, E., additional, Ravens, U., additional, Van Der Pouw Kraan, C., additional, Schirmer, S., additional, Fledderus, J., additional, Moerland, P., additional, Leyen, T., additional, Piek, J., additional, Van Royen, N., additional, Horrevoets, A., additional, Fleissner, F., additional, Jazbutyte, V., additional, Fiedler, J., additional, Galuppo, P., additional, Mayr, M., additional, Ertl, G., additional, Bauersachs, J., additional, Thum, T., additional, Protze, S., additional, Bussek, A., additional, Li, F., additional, Hoo, R., additional, Lam, K., additional, Xu, A., additional, Subramanian, P., additional, Karshovska, E., additional, Megens, R., additional, Akhtar, S., additional, Heyll, K., additional, Jansen, Y., additional, Weber, C., additional, Schober, A., additional, Zafeiriou, M., additional, Noack, C., additional, Renger, A., additional, Dietz, R., additional, Zelarayan, L., additional, Bergmann, M., additional, Meln, I., additional, Malashicheva, A., additional, Anisimov, S., additional, Kalinina, N., additional, Sysoeva, V., additional, Zaritskey, A., additional, Barbuti, A., additional, Scavone, A., additional, Mazzocchi, N., additional, Crespi, A., additional, Capilupo, D., additional, Difrancesco, D., additional, Qian, L., additional, Shim, W., additional, Gu, Y., additional, Mohammed, S., additional, Wong, P., additional, Zafiriou, M., additional, Schaeffer, H., additional, Kovacs, P., additional, Simon, J., additional, Varro, A., additional, Athias, P., additional, Wolf, J., additional, Bouchot, O., additional, Vandroux, D., additional, Mathe, A., additional, De Carvalho, A., additional, Laurent, G., additional, Rainer, P., additional, Huber, M., additional, Edelmann, F., additional, Stojakovic, T., additional, Trantina-Yates, A., additional, Trauner, M., additional, Pieske, B., additional, Von Lewinski, D., additional, De Jong, A., additional, Maass, A., additional, Oberdorf-Maass, S., additional, Van Gelder, I., additional, Lin, Y., additional, Li, J., additional, Wang, F., additional, He, Y., additional, Li, X., additional, Xu, H., additional, Yang, X., additional, Coppini, R., additional, Ferrantini, C., additional, Ferrara, C., additional, Rossi, A., additional, Mugelli, A., additional, Poggesi, C., additional, Cerbai, E., additional, Rozmaritsa, N., additional, Voigt, N., additional, Dobrev, D., additional, Kienitz, M.-C., additional, Zoidl, G., additional, Bender, K., additional, Pott, L., additional, Kohajda, Z., additional, Kristof, A., additional, Virag, L., additional, Jost, N., additional, Trafford, A., additional, Prnjavorac, B., additional, Mujaric, E., additional, Jukic, J., additional, Abduzaimovic, K., additional, Brack, K., additional, Patel, V., additional, Coote, J., additional, Ng, G., additional, Wilders, R., additional, Van Ginneken, A., additional, Verkerk, A., additional, Xaplanteris, P., additional, Vlachopoulos, C., additional, Baou, K., additional, Vassiliadou, C., additional, Dima, I., additional, Ioakeimidis, N., additional, Stefanadis, C., additional, Ruifrok, W., additional, Qian, C., additional, Sillje, H., additional, Van Goor, H., additional, Van Veldhuisen, D., additional, Van Gilst, W., additional, De Boer, R., additional, Schmidt, K., additional, Kaiser, F., additional, Erdmann, J., additional, De Wit, C., additional, Barnett, O., additional, Kyyak, Y., additional, Cesana, F., additional, Boffi, L., additional, Mauri, T., additional, Alloni, M., additional, Betelli, M., additional, Nava, S., additional, Giannattasio, C., additional, Mancia, G., additional, Vilskersts, R., additional, Kuka, J., additional, Svalbe, B., additional, Liepinsh, E., additional, Dambrova, M., additional, Zakrzewicz, A., additional, Maroski, J., additional, Vorderwuelbecke, B., additional, Fiedorowicz, K., additional, Da Silva-Azevedo, L., additional, Pries, A., additional, Gryglewska, B., additional, Necki, M., additional, Zelawski, M., additional, Grodzicki, T., additional, Scoditti, E., additional, Massaro, M., additional, Carluccio, M., additional, Distante, A., additional, Storelli, C., additional, De Caterina, R., additional, Kocgirli, O., additional, Valcaccia, S., additional, Dao, V., additional, Suvorava, T., additional, Kumpf, S., additional, Floeren, M., additional, Oppermann, M., additional, Kojda, G., additional, Leo, C., additional, Ziogas, J., additional, Favaloro, J., additional, Woodman, O., additional, Goettsch, W., additional, Marton, A., additional, Goettsch, C., additional, Morawietz, H., additional, Khalifa, E., additional, Ashour, Z., additional, Rupprecht, V., additional, Scalera, F., additional, Martens-Lobenhoffer, J., additional, Bode-Boeger, S., additional, Li, W., additional, Kwan, Y., additional, Leung, G., additional, Patella, F., additional, Mercatanti, A., additional, Pitto, L., additional, Rainaldi, G., additional, Tsimafeyeu, I., additional, Tishova, Y., additional, Wynn, N., additional, Kalinchenko, S., additional, Clemente Lorenzo, M., additional, Grande, M., additional, Barriocanal, F., additional, Aparicio, M., additional, Martin, A., additional, Hernandez, J., additional, Lopez Novoa, J., additional, Martin Luengo, C., additional, Kurlianskaya, A., additional, Denisevich, T., additional, Barth, N., additional, Loot, A., additional, Fleming, I., additional, Wang, Y., additional, Gabrielsen, A., additional, Ripa, R., additional, Jorgensen, E., additional, Kastrup, J., additional, Arderiu, G., additional, Pena, E., additional, Kobus, K., additional, Czyszek, J., additional, Kozlowska-Wiechowska, A., additional, Milkiewicz, P., additional, Milkiewicz, M., additional, Madonna, R., additional, Montebello, E., additional, Geng, Y., additional, Chin-Dusting, J., additional, Michell, D., additional, Skilton, M., additional, Dixon, J., additional, Dart, A., additional, Moore, X., additional, Ehrbar, M., additional, Reichmuth, P., additional, Heinimann, N., additional, Hewing, B., additional, Stangl, V., additional, Stangl, K., additional, Laule, M., additional, Baumann, G., additional, Ludwig, A., additional, Widmer-Teske, R., additional, Mueller, A., additional, Stieger, P., additional, Tillmanns, H., additional, Braun-Dullaeus, R., additional, Sedding, D., additional, Troidl, K., additional, Eller, L., additional, Benli, I., additional, Apfelbeck, H., additional, Schierling, W., additional, Troidl, C., additional, Schaper, W., additional, Schmitz-Rixen, T., additional, Hinkel, R., additional, Trenkwalder, T., additional, Pfosser, A., additional, Globisch, F., additional, Stachel, G., additional, Lebherz, C., additional, Bock-Marquette, I., additional, Kupatt, C., additional, Seyler, C., additional, Duthil-Straub, E., additional, Zitron, E., additional, Scholz, E., additional, Thomas, D., additional, Gierten, J., additional, Karle, C., additional, Fink, R., additional, Padro, T., additional, Lugano, R., additional, Garcia-Arguinzonis, M., additional, Schuchardt, M., additional, Pruefer, J., additional, Toelle, M., additional, Pruefer, N., additional, Jankowski, V., additional, Jankowski, J., additional, Zidek, W., additional, Van Der Giet, M., additional, Fransen, P., additional, Van Hove, C., additional, Michiels, C., additional, Van Langen, J., additional, Bult, H., additional, Quarck, R., additional, Wynants, M., additional, Alfaro-Moreno, E., additional, Rosario Sepulveda, M., additional, Wuytack, F., additional, Van Raemdonck, D., additional, Meyns, B., additional, Delcroix, M., additional, Christofi, F., additional, Wijetunge, S., additional, Sever, P., additional, Hughes, A., additional, Ohanian, J., additional, Forman, S., additional, Ohanian, V., additional, Gibbons, C., additional, Vernia, S., additional, Das, A., additional, Shah, V., additional, Casado, M., additional, Bielenberg, W., additional, Daniel, J., additional, Daniel, J.-M., additional, Hersemeyer, K., additional, Schmidt-Woell, T., additional, Kaetzel, D., additional, Tillmans, H., additional, Kanse, S., additional, Tuncay, E., additional, Kandilci, H., additional, Zeydanli, E., additional, Sozmen, N., additional, Akman, D., additional, Yildirim, S., additional, Turan, B., additional, Nagy, N., additional, Acsai, K., additional, Farkas, A., additional, Papp, J., additional, Toth, A., additional, Viero, C., additional, Mason, S., additional, Williams, A., additional, Marston, S., additional, Stuckey, D., additional, Dyer, E., additional, Song, W., additional, El Kadri, M., additional, Hart, G., additional, Hussain, M., additional, Faltinova, A., additional, Gaburjakova, J., additional, Urbanikova, L., additional, Hajduk, M., additional, Tomaskova, B., additional, Antalik, M., additional, Zahradnikova, A., additional, Steinwascher, P., additional, Jaquet, K., additional, Muegge, A., additional, Wang, G., additional, Zhang, M., additional, Tesi, C., additional, Ter Keurs, H., additional, Kettlewell, S., additional, Smith, G., additional, Workman, A., additional, Lenaerts, I., additional, Holemans, P., additional, Sokolow, S., additional, Schurmans, S., additional, Herchuelz, A., additional, Sipido, K., additional, Antoons, G., additional, Wehrens, X., additional, Li, N., additional, Respress, J. R., additional, De Almeida, A., additional, Van Oort, R., additional, Lohmann, H., additional, Saes, M., additional, Messer, A., additional, Copeland, O., additional, Leung, M., additional, Matthes, F., additional, Steinbrecher, J., additional, Salinas-Riester, G., additional, Opitz, L., additional, Hasenfuss, G., additional, Lehnart, S., additional, Caracciolo, G., additional, Eleid, M., additional, Carerj, S., additional, Chandrasekaran, K., additional, Khandheria, B., additional, Sengupta, P., additional, Riaz, I., additional, Tyng, L., additional, Dou, Y., additional, Seymour, A., additional, Dyer, C., additional, Griffin, S., additional, Haswell, S., additional, Greenman, J., additional, Yasushige, S., additional, Amorim, P., additional, Nguyen, T., additional, Schwarzer, M., additional, Mohr, F., additional, Doenst, T., additional, Popin Sanja, S., additional, Lalosevic, D., additional, Capo, I., additional, Momcilov Popin, T., additional, Astvatsatryan, A., additional, Senan, M., additional, Shafieian, G., additional, Goncalves, N., additional, Falcao-Pires, I., additional, Henriques-Coelho, T., additional, Moreira-Goncalves, D., additional, Leite-Moreira, A., additional, Bronze Carvalho, L., additional, Azevedo, J., additional, Andrade, M., additional, Arroja, I., additional, Relvas, M., additional, Morais, G., additional, Seabra, M., additional, Aleixo, A., additional, Winter, J., additional, Zabunova, M., additional, Mintale, I., additional, Lurina, D., additional, Narbute, I., additional, Zakke, I., additional, Erglis, A., additional, Marcinkevics, Z., additional, Kusnere, S., additional, Abolins, A., additional, Aivars, J., additional, Rubins, U., additional, Nassar, Y., additional, Monsef, D., additional, Hamed, G., additional, Abdelshafy, S., additional, Chen, L., additional, Wu, Y., additional, Wang, J., additional, Cheng, C., additional, Sternak, M., additional, Khomich, T., additional, Jakubowski, A., additional, Szafarz, M., additional, Szczepanski, W., additional, Mateuszuk, L., additional, Szymura-Oleksiak, J., additional, Chlopicki, S., additional, Sulicka, J., additional, Strach, M., additional, Kierzkowska, I., additional, Surdacki, A., additional, Mikolajczyk, T., additional, Balwierz, W., additional, Guzik, T., additional, Dmitriev, V., additional, Oschepkova, E., additional, Polovitkina, O., additional, Titov, V., additional, Rogoza, A., additional, Shakur, R., additional, Metcalfe, S., additional, Bradley, J., additional, Demyanets, S., additional, Kaun, C., additional, Kastl, S., additional, Pfaffenberger, S., additional, Huk, I., additional, Maurer, G., additional, Huber, K., additional, Wojta, J., additional, Eriksson, O., additional, Aberg, M., additional, Siegbahn, A., additional, Niccoli, G., additional, Sgueglia, G., additional, Conte, M., additional, Giubilato, S., additional, Cosentino, N., additional, Ferrante, G., additional, Crea, F., additional, Ilisei, D., additional, Leon, M., additional, Mitu, F., additional, Kyriakakis, E., additional, Philippova, M., additional, Cavallari, M., additional, Bochkov, V., additional, Biedermann, B., additional, De Libero, G., additional, Erne, P., additional, Resink, T., additional, Bakogiannis, C., additional, Antoniades, C., additional, Tousoulis, D., additional, Demosthenous, M., additional, Psarros, C., additional, Sfyras, N., additional, Channon, K., additional, Del Turco, S., additional, Navarra, T., additional, Basta, G., additional, Carnicelli, V., additional, Frascarelli, S., additional, Zucchi, R., additional, Kostareva, A., additional, Sjoberg, G., additional, Gudkova, A., additional, Semernin, E., additional, Shlyakhto, E., additional, Sejersen, T., additional, Cucu, N., additional, Anton, M., additional, Stambuli, D., additional, Botezatu, A., additional, Arsene, C., additional, Lupeanu, E., additional, Anton, G., additional, Patsch, J., additional, Huber, E., additional, Lande, C., additional, Cecchettini, A., additional, Tedeschi, L., additional, Trivella, M., additional, Citti, L., additional, Chen, B., additional, Ma, Y., additional, Yang, Y., additional, Ma, X., additional, Liu, F., additional, Hasanzad, M., additional, Rejali, L., additional, Fathi, M., additional, Minassian, A., additional, Mohammad Hassani, R., additional, Najafi, A., additional, Sarzaeem, M., additional, Sezavar, S., additional, Akhmedov, A., additional, Klingenberg, R., additional, Yonekawa, K., additional, Lohmann, C., additional, Gay, S., additional, Maier, W., additional, Neithard, M., additional, Luescher, T., additional, Xie, X., additional, Fu, Z., additional, Kevorkov, A., additional, Verduci, L., additional, Cremisi, F., additional, Wonnerth, A., additional, Katsaros, K., additional, Zorn, G., additional, Weiss, T., additional, De Rosa, R., additional, Galasso, G., additional, Piscione, F., additional, Santulli, G., additional, Iaccarino, G., additional, Piccolo, R., additional, Luciano, R., additional, Chiariello, M., additional, Szymanski, M., additional, Schoemaker, R., additional, Hillege, H., additional, Rizzo, S., additional, Basso, C., additional, Thiene, G., additional, Valente, M., additional, Rickelt, S., additional, Franke, W., additional, Bartoloni, G., additional, Bianca, S., additional, Giurato, E., additional, Barone, C., additional, Ettore, G., additional, Bianca, I., additional, Eftekhari, P., additional, Wallukat, G., additional, Bekel, A., additional, Heinrich, F., additional, Fu, M., additional, Briedert, M., additional, Briand, J., additional, Roegel, J., additional, Pilichou, K., additional, Korkmaz, S., additional, Radovits, T., additional, Pali, S., additional, Hirschberg, K., additional, Zoellner, S., additional, Loganathan, S., additional, Karck, M., additional, Szabo, G., additional, Pucci, A., additional, Pantaleo, J., additional, Martino, S., additional, Pelosi, G., additional, Matteucci, M., additional, Kusmic, C., additional, Vesentini, N., additional, Piccolomini, F., additional, Viglione, F., additional, L'abbate, A., additional, Slavikova, J., additional, Chottova Dvorakova, M., additional, Kummer, W., additional, Campanile, A., additional, Spinelli, L., additional, Ciccarelli, M., additional, De Gennaro, S., additional, Assante Di Panzillo, E., additional, Trimarco, B., additional, Akbarzadeh Najar, R., additional, Ghaderian, S., additional, Tabatabaei Panah, A., additional, Vakili, H., additional, Rezaei Farimani, A., additional, Rezaie, G., additional, Beigi Harchegani, A., additional, Hamdani, N., additional, Gavina, C., additional, Van Der Velden, J., additional, Niessen, H., additional, Stienen, G., additional, Paulus, W., additional, Moura, C., additional, Lamego, I., additional, Eloy, C., additional, Areias, J., additional, Bonda, T., additional, Dziemidowicz, M., additional, Hirnle, T., additional, Dmitruk, I., additional, Kaminski, K., additional, Musial, W., additional, Winnicka, M., additional, Villar, A., additional, Merino, D., additional, Ares, M., additional, Pilar, F., additional, Valdizan, E., additional, Hurle, M., additional, Nistal, J., additional, Vera, V., additional, Karuppasamy, P., additional, Chaubey, S., additional, Dew, T., additional, Sherwood, R., additional, Desai, J., additional, John, L., additional, Marber, M., additional, Kunst, G., additional, Cipolletta, E., additional, Attanasio, A., additional, Del Giudice, C., additional, Campiglia, P., additional, Illario, M., additional, Berezin, A., additional, Koretskaya, E., additional, Bishop, E., additional, Fearon, I., additional, Heger, J., additional, Warga, B., additional, Abdallah, Y., additional, Meyering, B., additional, Schlueter, K., additional, Piper, H., additional, Euler, G., additional, Lavorgna, A., additional, Cecchetti, S., additional, Rio, T., additional, Coluzzi, G., additional, Carrozza, C., additional, Conti, E., additional, Andreotti, F., additional, Glavatskiy, A., additional, Uz, O., additional, Kardesoglu, E., additional, Yiginer, O., additional, Bas, S., additional, Ipcioglu, O., additional, Ozmen, N., additional, Aparci, M., additional, Cingozbay, B., additional, Ivanes, F., additional, Hillaert, M., additional, Susen, S., additional, Mouquet, F., additional, Doevendans, P., additional, Jude, B., additional, Montalescot, G., additional, Van Belle, E., additional, Castellani, C., additional, Angelini, A., additional, De Boer, O., additional, Van Der Loos, C., additional, Gerosa, G., additional, Van Der Wal, A., additional, Dumitriu, I., additional, Baruah, P., additional, Kaski, J., additional, Maytham, O., additional, D Smith, J., additional, Rose, M., additional, Cappelletti, A., additional, Pessina, A., additional, Mazzavillani, M., additional, Calori, G., additional, Margonato, A., additional, Cassese, S., additional, D'anna, C., additional, Leo, A., additional, Silenzi, A., additional, Baca', M., additional, Biasucci, L., additional, Baller, D., additional, Gleichmann, U., additional, Holzinger, J., additional, Bitter, T., additional, Horstkotte, D., additional, Antonopoulos, A., additional, Miliou, A., additional, Triantafyllou, C., additional, Masson, W., additional, Siniawski, D., additional, Sorroche, P., additional, Casanas, L., additional, Scordo, W., additional, Krauss, J., additional, Cagide, A., additional, Huang, T., additional, Wiedon, A., additional, Lee, S., additional, Walker, K., additional, O'dea, K., additional, Perez Berbel, P., additional, Arrarte Esteban, V., additional, Garcia Valentin, M., additional, Sola Villalpando, M., additional, Lopez Vaquero, C., additional, Caballero, L., additional, Quintanilla Tello, M., additional, Sogorb Garri, F., additional, Duerr, G., additional, Elhafi, N., additional, Bostani, T., additional, Swieny, L., additional, Kolobara, E., additional, Welz, A., additional, Roell, W., additional, Dewald, O., additional, Kaludercic, N., additional, Takimoto, E., additional, Nagayama, T., additional, Chen, K., additional, Shih, J., additional, Kass, D., additional, Di Lisa, F., additional, Paolocci, N., additional, Vinet, L., additional, Pezet, M., additional, Briec, F., additional, Previlon, M., additional, Rouet-Benzineb, P., additional, Hivonnait, A., additional, Charpentier, F., additional, Mercadier, J., additional, Cobo, M., additional, Llano, M., additional, Montalvo, C., additional, Exposito, V., additional, Meems, L., additional, Westenbrink, B., additional, Biesmans, L., additional, Bito, V., additional, Driessen, R., additional, Huysmans, C., additional, Mourouzis, I., additional, Pantos, C., additional, Galanopoulos, G., additional, Gavra, M., additional, Perimenis, P., additional, Spanou, D., additional, Cokkinos, D., additional, Panasenko, T., additional, Partsch, S., additional, Harjung, C., additional, Bogdanova, A., additional, Mihov, D., additional, Mocharla, P., additional, Yakushev, S., additional, Vogel, J., additional, Gassmann, M., additional, Tavakoli, R., additional, Johansen, D., additional, Sanden, E., additional, Xi, C., additional, Sundset, R., additional, Ytrehus, K., additional, Bliksoen, M., additional, Rutkovskiy, A., additional, Mariero, L., additional, Vaage, I., additional, Stenslokken, K., additional, Pisarenko, O., additional, Shulzhenko, V., additional, Studneva, I., additional, Serebryakova, L., additional, Tskitishvili, O., additional, Pelogeykina, Y., additional, Timoshin, A., additional, Vanin, A., additional, Ziberna, L., additional, Lunder, M., additional, Drevensek, G., additional, Passamonti, S., additional, Gorza, L., additional, Ravara, B., additional, Scapin, C., additional, Vitadello, M., additional, Zigrino, F., additional, Gwathmey, J., additional, Del Monte, F., additional, Vilahur, G., additional, Juan-Babot, O., additional, Onate, B., additional, Casani, L., additional, Lemoine, S., additional, Calmettes, G., additional, Jaspard-Vinassa, B., additional, Duplaa, C., additional, Couffinhal, T., additional, Diolez, P., additional, Dos Santos, P., additional, Fusco, A., additional, Sorriento, D., additional, Cervero, P., additional, Feliciello, A., additional, Barnucz, E., additional, Kozichova, K., additional, Hlavackova, M., additional, Neckar, J., additional, Kolar, F., additional, Novakova, O., additional, Novak, F., additional, Barsanti, C., additional, Abraham, N., additional, Muntean, D., additional, Mirica, S., additional, Duicu, O., additional, Raducan, A., additional, Hancu, M., additional, Fira-Mladinescu, O., additional, Ordodi, V., additional, Voelkl, J., additional, Haubner, B., additional, Neely, G., additional, Moriell, C., additional, Seidl, S., additional, Pachinger, O., additional, Penninger, J., additional, and Metzler, B., additional

Published
2010
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25. Phospholamban ablation reduces the propensity for triggered activity in CPVT transgenic heart cells despite increased SR Ca2+ load.

Author

Gusev, K. and Lehnart, S. E.

Subjects
*RYANODINE receptors, *SARCOPLASMIC reticulum, *HEART cells
Abstract

The cardiac ryanodine receptor (RyR2), the principal Ca2+ release channel of the heart, is affected by patient mutations and catecholaminergic stress causing defective channel closure, irregular Ca2+ triggered action potentials (tAPs), and a ventricular arrhythmia syndrome (CPVT). Based on results obtained in heterologous overexpression models of CPVT mutant RyR2 channels, other groups suggested that catecholaminergic stimulation may lead to triggered activity by reducing the threshold for store overload-induced Ca2+ release. We have previously shown that heterozygous RyR2-R2474S (RyR2RS) knock-in mice reproduce the characteristic patient phonotype of CPVT. To clarify the physiological arrhythmia mechanism, we evaluated phospholamban deficient (PLN-/-;RyR2RS) cells with constitutive sarcoplasmic reticulum (SR) Ca2+ store overload. Double transgenic model: heterozygous RyR2RS knock-in mice were crossed with PLN-/- mice to produce RyR2RS;PLN-/- mice established in the C57Bl6 background. Electrophysiology: in vivo ECG as well as current-clamp combined with intracellular Ca2+ imaging of isolated ventricular myocytes (37C, fluo-3) was used to evaluate the influence of SR Ca2+ load on arrhythmogenic behavior. Comparing RyR2RS;PLN-/-vs. RyR2RS;PLN+/+ mice showed for PLN deficient RS cells: (1) significant QT interval shortening (60±2 ms vs. 68±2 ms, respectively; p<0.05); (2) significant action-potential shortening (APD90: 89±4 ms vs. 117±8 ms, respectively; p<0.05); (3) significantly accelerated Ca2+ transient decay (28±2 ms vs. 69±5 ms, p<0.001); and (4) significantly increased SR Ca2+ load (ΔF/F0: 9.7±1.6 vs. 5.3±1.4, respectively; p<0.001). (5) As expected, acute β-adrenergic stimulation with 30 nM isoproterenol resulted in no further increase of SR Ca2+ load in PLN-/- (ΔF/F0: RyR2RS;PLN-/-8.1±2.7 vs. RyR2RS;PLN+/+ 7.0±1.7; n.s.). (6) Despite maximal, constitutive SR Ca2+ loading in RyR2RS;PLN-/- cardiomyocytes, the occurrence of tAPs during β-adrenergic stimulation was significantly decreased in RyR2RS;PLN-/- cells (RyR2RS;PLN+/+: 9 out of 12 cells (75%); RyR2RS;PLN-/-: 1 out of 10 cells (10%) had tAP; p<0.05). In summary, our data suggest that maximal upregulation of SERCA2a activity in PLN-/- (1) leads to increased SR Ca2+ load and accelerated cytosolic Ca2+ removal, which shortens the APD and the QT interval in vivo; and (2) decreases the propensity for tAPs in the context of a highly arrhythmogenic CPVT model with significantly increased diastolic SR Ca2+ leak. This suggests that, contrary to expectation, increased SR Ca2+ per se, at levels occurring during catecholaminergic stress, may not trigger APs under physiological conditions. An increased susceptibility of RyR2CaRS cells for tAPs might be blunted by accelerated SR Ca2+ uptake and altered diastolic Ca2+ handling dynamics. [ABSTRACT FROM AUTHOR]

Published
2013

27. P608 ANP potentiates catecholaminergic stress in early cardiac disease.

Author

Perera, R K, Steinbrecher, J H, Lehnart, S E, and Nikolaev, V O

Subjects
ATRIAL natriuretic peptides, CATECHOLAMINES, HEART diseases, FLUORESCENCE resonance energy transfer, AORTIC coarctation, SARCOLEMMA
Abstract

Purpose: Atrial natriuretic peptide (ANP) is a well-known vasodilatory factor and crucial hormone for adaptation to increased blood pressure. ANP plasma levels rise upon elevated cardiac afterload during aortic stenosis and, via guanylyl cyclase A, stimulate cardiomyocyte cGMP levels. Cardiac cGMP is considered as a protective second messenger which counteracts detrimental effects of the chronic β-adrenoceptor (β-AR)-mediated cAMP signaling. Previous studies analyzed cyclic nucleotide signaling mostly in advanced chronic heart disease. The purpose of this work was to investigate subcellular changes in cAMP/cGMP signaling and their interactions in early cardiac hypertrophy.Methods: We used a compensated cardiac hypertrophy model induced by transverse aortic constriction (TAC) in mice. Heart function was evaluated by echocardiography. Plasma ANP was quantified by ELISA. Heart rates were measured from ECG recordings in intact perfused Langendorff hearts. Cardiomyocyte (CM) contractility was analyzed by sarcomere shortening. To monitor cAMP in real time, we generated transgenic mice expressing the membrane targeted Förster resonance energy transfer (FRET) biosensor pmEpac1, localized to the sarcolemma. Individual PDE activities were measured using a classical biochemical assay.Results: 8 weeks post TAC, animals developed mild hypertrophy accompanied by a 2-fold increase in plasma ANP levels. Unexpectedly, ANP could potentiate catecholamine-induced positive chronotropic response in TAC but not sham hearts, which was accompanied by enhanced contractility in single isolated TAC CMs. FRET analysis revealed increased β1- but decreased β2-AR-cAMP signals in TAC cells without any change in β-AR densities. Interestingly, local β2-AR-associated PDE effects were dramatically altered despite unchanged whole cell PDE activities. In particular, we could uncover a switch from the PDE3- to PDE2-dependent regulation of β2-AR-cAMP signals. Since these PDEs are inversely regulated by cGMP, we tested the effect of ANP on β2-AR signaling. We found a turnaround of the cGMP/cAMP crosstalk in this microdomain, which was due to PDE2 and PDE3 redistribution and did directly translate into functional response.Conclusions: We could show that in compensated hypertrophy, elevated levels of ANP potentiate catecholamine-stimulated inotropic and chronotropic effects. This is achieved by a switch in PDE2- and PDE3-dependent regulation of β2-and β1-AR-cAMP signaling. We propose that in early cardiac disease, ANP might transiently compensate an increased demand on cardiac output. [ABSTRACT FROM PUBLISHER]

Published
2014
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28. Multiphoton Imaging of Ca 2+ Instability in Acute Myocardial Slices from a RyR2 R2474S Murine Model of Catecholaminergic Polymorphic Ventricular Tachycardia.

Author

Borile G, Zaglia T, E Lehnart S, and Mongillo M

Abstract

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a familial stress-induced arrhythmia syndrome, mostly caused by mutations in Ryanodine receptor 2 ( RyR 2), the sarcoplasmic reticulum (SR) Ca 2+ release channel in cardiomyocytes. Pathogenetic mutations lead to gain of function in the channel, causing arrhythmias by promoting diastolic spontaneous Ca 2+ release (SCR) from the SR and delayed afterdepolarizations. While the study of Ca 2+ dynamics in single cells from murine CPVT models has increased our understanding of the disease pathogenesis, questions remain on the mechanisms triggering the lethal arrhythmias at tissue level. Here, we combined subcellular analysis of Ca 2+ signals in isolated cardiomyocytes and in acute thick ventricular slices of RyR2 R2474S knock-in mice, electrically paced at different rates (1-5 Hz), to identify arrhythmogenic Ca 2+ dynamics, from the sub- to the multicellular perspective. In both models, RyR2 R2474S cardiomyocytes had increased propensity to develop SCR upon adrenergic stimulation, which manifested, in the slices, with Ca 2+ alternans and synchronous Ca 2+ release events in neighboring cardiomyocytes. Analysis of Ca 2+ dynamics in multiple cells in the tissue suggests that SCRs beget SCRs in contiguous cells, overcoming the protective electrotonic myocardial coupling, and potentially generating arrhythmia triggering foci. We suggest that intercellular interactions may underscore arrhythmic propensity in CPVT hearts with 'leaky' RyR2.

Published
2021
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29. A protocol for registration and correction of multicolour STED superresolution images.

Author

Hebisch E, Wagner E, Westphal V, Sieber JJ, and Lehnart SE

Subjects
Animals, Cells, Cultured, Mice, Image Processing, Computer-Assisted methods, Myocytes, Cardiac enzymology, Optical Imaging methods, Ryanodine Receptor Calcium Release Channel analysis
Abstract

Multicolour fluorescence imaging by STimulated Emission Depletion (STED) superresolution microscopy with doughnut-shaped STED laser beams based on different wavelengths for each colour channel requires precise image registration. This is especially important when STED imaging is used for co-localisation studies of two or more native proteins in biological specimens to analyse nanometric subcellular spatial arrangements. We developed a robust postprocessing image registration protocol, with the aim to verify and ultimately optimise multicolour STED image quality. Importantly, this protocol will support any subsequent quantitative localisation analysis at nanometric scales. Henceforth, using an approach that registers each colour channel present during STED imaging individually, this protocol reliably corrects for optical aberrations and inadvertent sample drift. To achieve the latter goal, the protocol combines the experimental sample information, from corresponding STED and confocal images using the same optical beam path and setup, with that of an independent calibration sample. As a result, image registration is based on a strategy that maximises the cross-correlation between sequentially acquired images of the experimental sample, which are strategically combined by the protocol. We demonstrate the general applicability of the image registration protocol by co-staining of the ryanodine receptor calcium release channel in primary mouse cardiomyocytes. To validate this new approach, we identify user-friendly criteria, which - if fulfilled - support optimal image registration. In summary, we introduce a new method for image registration and rationally based postprocessing steps through a highly standardised protocol for multicolour STED imaging, which directly supports the reproducibility of protein co-localisation analyses. Although the reference protocol is discussed exemplarily for two-colour STED imaging, it can be readily expanded to three or more colours and STED channels., (© 2017 The Authors. Journal of Microscopy published by JohnWiley & Sons Ltd on behalf of Royal Microscopical Society.)

Published
2017
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30. Regulation of ryanodine receptors in the heart.

Author

Lehnart S and Marks AR

Subjects
Animals, Cardiovascular Diseases metabolism, Cardiovascular Diseases physiopathology, Catecholamines physiology, Humans, Ryanodine Receptor Calcium Release Channel physiology, Myocardium metabolism, Ryanodine Receptor Calcium Release Channel metabolism
Published
2007
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31. Overexpression of FK506-binding protein FKBP12.6 in cardiomyocytes reduces ryanodine receptor-mediated Ca(2+) leak from the sarcoplasmic reticulum and increases contractility.

Author

Prestle J, Janssen PM, Janssen AP, Zeitz O, Lehnart SE, Bruce L, Smith GL, and Hasenfuss G

Subjects
Adenoviridae genetics, Animals, Blotting, Western, Caffeine pharmacology, Cells, Cultured, Gene Transfer Techniques, Myocardial Contraction drug effects, Myocardial Contraction genetics, Myocardium cytology, Protein Isoforms, Rabbits, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Ruthenium Red pharmacology, Sarcoplasmic Reticulum drug effects, Sirolimus pharmacology, Tacrolimus pharmacology, Tacrolimus Binding Proteins genetics, Transfection, Calcium metabolism, Myocardial Contraction physiology, Myocardium metabolism, Ryanodine Receptor Calcium Release Channel metabolism, Sarcoplasmic Reticulum metabolism, Tacrolimus Binding Proteins metabolism
Abstract

The FK506-binding protein FKBP12.6 is tightly associated with the cardiac sarcoplasmic reticulum (SR) Ca(2+)-release channel (ryanodine receptor type 2 [RyR2]), but the physiological function of FKBP12.6 is unclear. We used adenovirus (Ad)-mediated gene transfer to overexpress FKBP12.6 in adult rabbit cardiomyocytes. Western immunoblot and reverse transcriptase-polymerase chain reaction analysis revealed specific overexpression of FKBP12.6, with unchanged expression of endogenous FKBP12. FKBP12.6-transfected myocytes displayed a significantly higher (21%) fractional shortening (FS) at 48 hours after transfection compared with Ad-GFP-infected control cells (4.8+/-0.2% FS versus 4+/-0.2% FS, respectively; n=79 each; P:=0.001). SR-Ca(2+) uptake rates were monitored in beta-escin-permeabilized myocytes using Fura-2. Ad-FKBP12.6-infected cells showed a statistically significant higher rate of Ca(2+) uptake of 0.8+/-0.09 nmol/s(-)(1)/10(6) cells (n=8, P:<0.05) compared with 0.52+/-0.1 nmol/s(-)(1)/10(6) cells in sham-infected cells (n=8) at a [Ca(2+)] of 1 micromol/L. In the presence of 5 micromol/L ruthenium red to block Ca(2+) efflux via RyR2, SR-Ca(2+) uptake rates were not significantly different between groups. From these measurements, we calculate that SR-Ca(2+) leak through RyR2 is reduced by 53% in FKBP12.6-overexpressing cells. Caffeine-induced contractures were significantly larger in Ad-FKBP12.6-infected myocytes compared with Ad-GFP-infected control cells, indicating a higher SR-Ca(2+) load. Taken together, these data suggest that FKBP12.6 stabilizes the closed conformation state of RyR2. This may reduce diastolic SR-Ca(2+) leak and consequently increase SR-Ca(2+) release and myocyte shortening.

Published
2001
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32. Influence of cyclosporine A on contractile function, calcium handling, and energetics in isolated human and rabbit myocardium.

Author

Janssen PM, Zeitz O, Keweloh B, Siegel U, Maier LS, Barckhausen P, Pieske B, Prestle J, Lehnart SE, and Hasenfuss G

Subjects
Animals, Cold Temperature, Depression, Chemical, Dose-Response Relationship, Drug, Heart Failure metabolism, Humans, In Vitro Techniques, Rabbits, Sarcoplasmic Reticulum metabolism, Calcium metabolism, Cyclosporine pharmacology, Immunosuppressive Agents pharmacology, Myocardial Contraction drug effects, Myocardium metabolism, Oxygen Consumption drug effects
Abstract

Objective: The immunosuppressive drug Cyclosporine A (CsA) is a key substance in pharmacological therapy following solid organ transplantation and has been suggested to prevent cardiac hypertrophy. We investigated the direct effects of CsA on myocardial function, because these are largely unknown., Methods: In multicellular cardiac muscle preparations from end-stage failing and non-failing human hearts as well as from non-failing rabbit hearts we investigated the effects of CsA on contractile performance, sarcoplasmic reticulum (SR) Ca2+-load, cytosolic calcium transients, calcium sensitivity of the myofilaments, and myocardial oxygen consumption., Results: In failing human muscle preparations there was a concentration dependent decrease in contractile force; the maximal effect amounted to 55.6+/-6.4% of control while EC50 was reached at 1.0+/-0.3 nM (n=6). These concentrations are at and even below the therapeutic plasma levels. CsA decreased the aequorin light signal in human failing trabeculae to 71.5+/-5.9% (n=5), indicating decreased calcium transients. Estimation of the SR calcium load via measurement of rapid cooling contractures revealed a decrease to 84.4+/-6.5% in failing human preparations (n=6). Measurements of both decreased SR calcium load and force development in presence of CsA were also observed in four non-failing human muscle preparations. In rabbit muscle preparations (n=8), developed force decreased to 50.2+/-7.7% (n=8, EC50: 1.9+/-0.4 nM) and rapid cooling contractures to 74.0+/-7.4% of control at 100 nmol/l CsA. No direct effects were observed on myofilament calcium sensitivity nor on maximal force development of permeabilized preparations from the rabbit (n=7). Oxygen consumption measurements showed that CsA decreased the economy of contraction to 76.4+/-7.9% in rabbit preparations (n=8)., Conclusions: CsA causes a direct cardio-depressive effect at clinically relevant concentrations, most likely due to altered handling of Ca2+ by the SR.

Published
2000
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33. Preservation of contractile characteristics of human myocardium in multi-day cell culture.

Author

Janssen PM, Lehnart SE, Prestle J, and Hasenfuss G

Subjects
Electric Stimulation, Heart physiology, Humans, Tissue Preservation, Culture Techniques methods, Myocardial Contraction, Myocardium cytology
Abstract

Functional studies of different human cell types have been successfully conducted under in vitro conditions. Despite many efforts, it has not been possible to develop a human myocardial preparation in which contractile function can be studied over several days. We hypothesize that by mimicking the in vivo situation in an in vitro environment we can preserve viability and function of human myocardial preparations over several days. From explanted hearts of patients undergoing cardiac transplantation, multicellular preparations were dissected and mounted in a sterile muscle chamber. Muscles were stimulated at 0.5 or 1 Hz at 1.75 mmol/l Ca(2+), a pH of 7.4 and at 37 degrees C, and kept contracting isometrically for 2-6 days. This study shows for the first time that contractile function of human myocardial tissue can be preserved over several days; active force development had not significantly changed after 48 h (10.6+/-1.2 at t=0 v 11.4+/-2.8 mN/mm(2)at t=48, n=10), nor had diastolic force (1.0+/-0.1 v 0.9+/-0.1 mN/mm(2)). After at least 48 h, the contractile response to stimulation with 1 micromol/l isoproterenol was clearly present: developed force increased to 631+/-146% of control values, while half-relaxation time declined to 57+/-6% (n=7). In addition, both pharmacological responses and regulatory physiological behavior, such as post-rest potentiation and force-frequency relationships, are preserved. This technique allows the study of the regulation of contractile function of human myocardium in vitro and may be used to link changes in protein expression to consequent changes in myocardial contraction., (Copyright 1999 Academic Press.)

Published
1999
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34. Relationship between Na+-Ca2+-exchanger protein levels and diastolic function of failing human myocardium.

Author

Hasenfuss G, Schillinger W, Lehnart SE, Preuss M, Pieske B, Maier LS, Prestle J, Minami K, and Just H

Subjects
Adult, Aged, Calcium-Transporting ATPases metabolism, Female, Humans, In Vitro Techniques, Male, Middle Aged, Sarcoplasmic Reticulum enzymology, Cardiac Output, Low metabolism, Diastole physiology, Myocardium metabolism, Sodium-Calcium Exchanger
Abstract

Background: In the failing human heart, sarcoplasmic reticulum (SR) calcium handling is impaired, and therefore, calcium elimination and diastolic function may depend on the expression of sarcolemmal Na+-Ca2+ exchanger., Methods and Results: Force-frequency relations were studied in ventricular muscle strip preparations from failing human hearts (n=29). Protein levels of Na+-Ca2+ exchanger and SR Ca2+-ATPase were measured in the same hearts. Hearts were divided into 3 groups by discriminant analysis according to the behavior of diastolic function when stimulation rate of muscle strips was increased from 30 to 180 min-1. At 180 compared with 30 min-1, diastolic force was increased by 160%, maximum rate of force decline was decreased by 46%, and relaxation time was unchanged in group III. In contrast, in group I, diastolic force and maximum rate of force decline did not change, and relaxation time decreased by 20%. Na+-Ca2+ exchanger was 66% higher in group I than in group III. Na+-Ca2+ exchanger was inversely correlated with the frequency-dependent rise of diastolic force when stimulation rate was increased (r=-0.74; P<0.001). Compared with nonfailing human hearts (n=6), SR Ca2+-ATPase was decreased and Na+-Ca2+ exchanger unchanged in group III, whereas Na+-Ca2+ exchanger was increased and SR Ca2+-ATPase unchanged in group I. Results with group II hearts were between those of group I and group III hearts., Conclusions: By discriminating failing human hearts according to their diastolic function, we identified different phenotypes. Disturbed diastolic function occurs in hearts with decreased SR Ca2+-ATPase and unchanged Na+-Ca2+ exchanger, whereas increased expression of the Na+-Ca2+ exchanger is associated with preserved diastolic function.

Published
1999
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35. Sarcoplasmic reticulum proteins in heart failure.

Author

Lehnart SE, Schillinger W, Pieske B, Prestle J, Just H, and Hasenfuss G

Subjects
Animals, Calcium metabolism, Calreticulin, Calsequestrin metabolism, Humans, Ribonucleoproteins metabolism, Calcium-Binding Proteins metabolism, Calcium-Transporting ATPases metabolism, Cardiomyopathy, Dilated physiopathology, Heart Failure physiopathology, Myocardial Contraction physiology, Ryanodine Receptor Calcium Release Channel physiology, Sarcoplasmic Reticulum physiology, Sodium-Calcium Exchanger metabolism
Abstract

Altered calcium homeostasis may play a key role in the pathophysiology of human heart failure. Levels of sarcoplasmic reticulum (SR) proteins and sarcolemmal Na(+)-Ca2+ exchanger were analyzed by Western blot in failing and nonfailing human myocardium and related to myocardial function. Levels of the SR calcium release channel and of calcium storage proteins (calsequestrin and calreticulin) were not different in nonfailing and failing hearts. However, proteins involved in calcium removal were significantly altered in the failing human heart: (1) SR-Ca(2+)-ATPase levels and the ratio of SR-Ca(2+)-ATPase to its inhibitory protein phospholamban were significantly decreased, and (2) Na(+)-Ca2+ exchanger levels and the ratio of Na(+)-Ca2+ exchanger to SR-Ca(2+)-ATPase were significantly increased. SR-Ca(2+)-ATPase levels were closely correlated to systolic function as evaluated by frequency potentiation of contractile force. The frequency-dependent rise of diastolic force was inversely correlated with protein levels of Na(+)-Ca2+ exchanger. These findings indicate that altered expression of SR-Ca(2+)-ATPase and Na(+)-Ca2+ exchanger is relevant for altered systolic and diastolic function in human heart failure.

Published
1998
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36. Frequency-dependence of myocardial energetics in failing human myocardium as quantified by a new method for the measurement of oxygen consumption in muscle strip preparations.

Author

Meyer M, Keweloh B, Güth K, Holmes JW, Pieske B, Lehnart SE, Just H, and Hasenfuss G

Subjects
Biomechanical Phenomena, Diastole, Female, Humans, Male, Middle Aged, Reproducibility of Results, Cardiomyopathies metabolism, Electrophysiology methods, Myocardium metabolism, Oxygen Consumption
Abstract

Diastolic dysfunction at high heart rates may be associated with increased myocardial energy consumption. Frequency-dependent changes of isometric force and oxygen consumption (MVO2) were investigated in strip preparations from endstage failing human hearts exhibiting various degrees of diastolic dysfunction. MVO2 was determined by a new method which was validated. When stimulation rate was increased from 40 to 200 min-1 (n=7), developed force decreased from 16.5+/-4.3 to 7.9+/-2.9 mN/mm2 (P<0.01), diastolic force increased from 15.9+/-3.2 to 22.0+/-3.0 mN/mm2 (P<0.01), and total MVO2 increased from 2.6+/-0.6 to 4.7+/-0.9 ml/min/100 g (P<0.025). Resting MVO2 and resting force were 1.8+/-0.4 ml/min/100 g and 15.9+/-3.0 mN/mm2, respectively. After addition of 30 mm 2,3-butanedione monoxime (BDM) to inhibit crossbridges, resting MVO2 and resting force decreased by 46% (P<0.05) and 15% (P<0.01), respectively, indicating the presence of active force generation in unstimulated failing human myocardium. In each muscle preparation, there was a significant correlation between force-time integral (FTI) and total MVO2 (r=0.96+/-0.01). The strength of these correlations did not vary with the contribution of diastolic FTI to total FTI. The ratio of activity related MVO2 to developed FTI, an inverse index of the economy of contraction, increased depending on the rise of diastolic FTI at higher stimulation rates. In conclusion, in failing human myocardium, diastolic force development is occurring at the same energy expenditure as systolic force generation. Therefore, in muscle preparations with disturbed diastolic function economy of contraction decreases with higher stimulation rates, depending on the rise of diastolic force., (Copyright 1998 Academic Press.)

Published
1998
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37. Influence of SR Ca(2+)-ATPase and Na(+)-Ca(2+)-exchanger on the force-frequency relation.

Author

Schillinger W, Lehnart SE, Prestle J, Preuss M, Pieske B, Maier LS, Meyer M, Just H, and Hasenfuss G

Subjects
Biomechanical Phenomena, Cardiac Output, Low physiopathology, Humans, Subcellular Fractions physiology, Calcium-Transporting ATPases metabolism, Heart Rate physiology, Myocardial Contraction physiology, Sarcoplasmic Reticulum enzymology, Sodium-Calcium Exchanger metabolism
Abstract

The data presented indicate that altered systolic and diastolic function in failing human hearts may result from altered expression of calcium cycling proteins. Decreased systolic force production and inversion of the force-frequency relation seem to be related to reduced protein levels of SR Ca2+ ATPase and/or to increased protein levels of the Na(+)-Ca2+ exchanger resulting in an increased ratio of Na(+)-Ca2+ exchanger to SR Ca2+ ATPase. Impaired diastolic function may result from reduced SR Ca2+ ATPase and is most pronounced in failing hearts with lack of upregulation of the Na(+)-Ca2+ exchanger. Thus, failing hearts with reduced SR Ca2+ ATPase protein levels and unchanged Na(+)-Ca2+ exchanger protein levels exhibit severe impairment of both systolic and diastolic function.

Published
1998
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