Imperial College London
Alternate

Chris Rao

Faculty of Medicine, Department of Surgery & Cancer

Honorary Clinical Research Fellow
 
 
 
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Publications

Citation

BibTex format

@article{Ibrahim:2012:eurjhf/hfs038,
author = {Ibrahim, M and Navaratnarajah, M and Siedlecka, U and Rao, C and Dias, P and Moshkov, AV and Gorelik, J and Yacoub, MH and Terracciano, CM},
doi = {eurjhf/hfs038},
journal = {European Journal of Heart Failure},
pages = {571--580},
title = {Mechanical unloading reverses transverse tubule remodelling and normalizes local Ca2+-induced Ca2+ release in a rodent model of heart failure},
url = {http://dx.doi.org/10.1093/eurjhf/hfs038},
volume = {14},
year = {2012}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - AimsCa2+-induced Ca2+ release (CICR) is critical for contraction in cardiomyocytes. The transverse (t)-tubule system guarantees the proximity of the triggers for Ca2+ release [L-type Ca2+ channel, dihydropyridine receptors (DHPRs)] and the sarcoplasmic reticulum Ca2+ release channels [ryanodine receptors (RyRs)]. Transverse tubule disruption occurs early in heart failure (HF). Clinical studies of left ventricular assist devices in HF indicate that mechanical unloading induces reverse remodelling. We hypothesize that unloading of failing hearts normalizes t-tubule structure and improves CICR.Methods and resultsHeart failure was induced in Lewis rats by left coronary artery ligation for 12 weeks; sham-operated animals were used as controls. Failing hearts were mechanically unloaded for 4 weeks by heterotopic abdominal heart transplantation (HF-UN). HF reduced the t-tubule density measured by di-8-ANEPPS staining in isolated left ventricular myocytes, and this was reversed by unloading. The deterioration in the regularity of the t-tubule system in HF was also reversed in HF-UN. Scanning ion conductance microscopy showed the reappearance of normal surface striations in HF-UN. Electron microscopy revealed recovery of normal t-tubule microarchitecture in HF-UN. L-type Ca2+ current density, measured using whole-cell patch clamping, was reduced in HF but unaffected by unloading. The variance of the time-to-peak of the Ca2+ transient, an index of CICR dyssynchrony, was increased in HF and normalized by unloading. The increased Ca2+ spark frequency observed in HF was reduced in HF-UN. These results could be explained by the recoupling of orphaned RyRs in HF, as indicated by immunofluorescence.ConclusionsOur data show that mechanical unloading of the failing heart reverses the pathological remodelling of the t-tubule system and improves CICR.
AU  - Ibrahim,M
AU  - Navaratnarajah,M
AU  - Siedlecka,U
AU  - Rao,C
AU  - Dias,P
AU  - Moshkov,AV
AU  - Gorelik,J
AU  - Yacoub,MH
AU  - Terracciano,CM
DO  - eurjhf/hfs038
EP  - 580
PY  - 2012///
SN  - 1879-0844
SP  - 571
TI  - Mechanical unloading reverses transverse tubule remodelling and normalizes local Ca2+-induced Ca2+ release in a rodent model of heart failure
T2  - European Journal of Heart Failure
UR  - http://dx.doi.org/10.1093/eurjhf/hfs038
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000304530400004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/29598
VL  - 14
ER  -
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