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La heterogeneidad transmural y la remodelación del acoplamiento de excitación-contracción ventricular en la
Qing Lou1, Vadim V Fedorov, Alexey V Glukhov
1Department of Biomedical Engineering, Washington University, St. Louis, MO, USA.
Circulation
|April 20, 2011
Resumen
La insuficiencia cardíaca altera el acoplamiento excitación-contracción, causando diferencias espaciales en el manejo del calcio dentro del tejido cardíaco humano. Este estudio revela una remodelación heterogénea en los corazones con insuficiencia cardíaca, que afecta la función cardíaca.
Área de la Ciencia:
- Cardiología Cardiología.
- Fisiología Fisiología Fisiología.
- La bioquímica es la bioquímica.
Sus antecedentes:
- El acoplamiento excitación-contracción (EC) es crucial para la función cardíaca y se sabe que se altera en la insuficiencia cardíaca en etapa terminal.
- La heterogeneidad espacial de la remodelación del acoplamiento EC a nivel de tejido en corazones humanos con fallas sigue siendo poco comprendida.
Objetivo del estudio:
- Investigar la remodelación funcional del acoplamiento EC y el manejo de calcio en corazones humanos con y sin fallas.
- Para establecer la heterogeneidad espacial de estos procesos dentro del tejido cardíaco humano.
Principales métodos:
- Mapeo óptico simultáneo de potenciales de acción y transientes de calcio.
- Utilizó preparaciones de cuña ventricular izquierda con perfusión coronaria de corazones humanos.
- Comparación de fallas (n=5) y no fallas (n=6) de los corazones bajo diferentes ritmos de ritmo (40 y 100 bpm).
Principales resultados:
- Las fallas cardíacas mostraron una mayor duración transitoria del calcio en relación con la duración del potencial de acción en el subendocardio durante la bradicardia.
- El gradiente transmural de la duración transitoria del calcio se redujo en los corazones fallidos a tasas más rápidas.
- Se observaron formas transitorias anormales de calcio (plataforma aplanada, aumento de 2 componentes) en corazones con insuficiencia.
- Se observó una relajación transitoria más lenta del calcio y una reducción de la expresión de la Ca(2+) -ATPasa 2a en el retículo sarcoplásmico en el subendocardio en los corazones con insuficiencia.
Conclusiones:
- Este estudio proporciona la primera evidencia experimental de heterogeneidad transmural en el acoplamiento EC y el manejo del calcio en los corazones humanos.
- La insuficiencia cardíaca en etapa terminal se caracteriza por la remodelación heterogénea de los procesos de acoplamiento de EC y de manipulación de calcio.
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