Contractile protein function in failing and nonfailing human myocardium

G. Hasenfuss, L. A. Mulieri, B. J. Leavitt, P. D. Allen, C. Holubarsch, H. Just, N. R. Alpert

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Isometric heat and force measurements were used to relate mechanical performance to function of contractile proteins in muscle strips from failing and nonfailing human hearts (37°C, 60 beats per minute). Compared to control myocardium, crossbridge behavior was altered in myocardium from hearts with end-stage failing dilated and ischemic cardiomyopathy, resulting in increased crossbridge force-time integral by 33% and 36%, respectively. Peak isometric twitch tension was reduced significantly by 46% in muscle strips from hearts with dilated cardiomyopathy. In myocardium from hearts with ischemic cardiomyopathy peak isometric twitch tension was comparable to values from nonfailing hearts. Including all three types of myocardium, there was a close correlation between the number of crossbridge interactions during the isometric twitch (tension-dependent heat) and peak twitch tension (r=0.88; p < 0.001). Compared to control, in failing myocardium from dilated cardiomyopathic hearts, tension-independent heat (calcium cycling) was significantly reduced. This indicates that in dilated cardiomyopathy reduced peak twitch tension results from decreased calcium activation of contractile proteins with reduced number of crossbridge interactions during the isometric twitch. In ischemic cardiomyopathy mechanisms different from those observed in dilated cardiomyopathy seem to be involved in the development of heart failure.

Original languageEnglish (US)
Pages (from-to)107-116
Number of pages10
JournalBasic Research in Cardiology
Volume87
Issue numberSUPPL. 1
StatePublished - 1992
Externally publishedYes

Keywords

  • Calcium cycling
  • Crossbridge cycle
  • Crossbridge force-time integral
  • Myocardial failure
  • Myothermal measurements

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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