Document Detail

Calcium sensitivity of force in human ventricular cardiomyocytes from donor and failing hearts.
MedLine Citation:
PMID:  12479245     Owner:  NLM     Status:  MEDLINE    
In failing human myocardium changes occur, in particular, in isoform composition and phosphorylation level of the troponin T (TnT) and troponin I (TnI) subunits of the actin filament and the myosin light chains (MLC-1 and -2), but it is unclear to what extent they influence cardiac performance. This overview concentrates on the relation between contractile function, contractile protein composition and phosphorylation levels in small biopsies from control (donor) hearts, from biopsies obtained during open heart surgery (NYHA Class I-IV) and from end-stage failing (explanted, NYHA class IV) hearts. Furthermore, attention is paid to the effect of the catalytic subunit of protein kinase A on isometric force development in single Triton-skinned human cardiomyocytes isolated from donor and end-stage failing left ventricular myocardium at different resting sarcomere lengths. A reduction in sarcomere length from 2.2 to 1.8 microm caused reductions in maximum isometric force by approximately 35% both in donor and in failing cardiomyocytes. The midpoints of the calcium sensitivity curves (pCa50) of donor and end-stage failing hearts differed markedly at all sarcomere lengths (mean delta pCa50 = 0.22). Our findings indicate that 1) TnI phosphorylation contributes to the differences in calcium sensitivity between donor and end-stage failing hearts, 2) human ventricular myocardium is heterogeneous with respect of the phosphorylation of TnT, MLC-2 and the isoform distribution of MLC-1 and MLC-2, and 3) the Frank-Starling mechanism is preserved in end-stage failing myocardium.
J van der Velden; N M Boontje; Z Papp; L J Klein; F C Visser; J W de Jong; V J Owen; P B J Burton; G J M Stienen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Basic research in cardiology     Volume:  97 Suppl 1     ISSN:  0300-8428     ISO Abbreviation:  Basic Res. Cardiol.     Publication Date:  2002  
Date Detail:
Created Date:  2002-12-13     Completed Date:  2002-12-27     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0360342     Medline TA:  Basic Res Cardiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  I118-26     Citation Subset:  IM    
Laboratory for Physiology, Institute for Cardiovascular Research (ICaR-VU), Vrije Universiteit, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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MeSH Terms
Calcium / metabolism*
Cardiac Output, Low / physiopathology*
Cyclic AMP-Dependent Protein Kinases / pharmacology
Heart Transplantation*
Muscle Proteins / metabolism
Myocardial Contraction / physiology
Myocytes, Cardiac / drug effects,  physiology*
Sarcomeres / physiology
Tissue Donors*
Ventricular Function*
Reg. No./Substance:
0/Muscle Proteins; 7440-70-2/Calcium; EC AMP-Dependent Protein Kinases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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