Document Detail

Abnormal splicing in the N-terminal variable region of cardiac troponin T impairs systolic function of the heart with preserved Frank-Starling compensation.
MedLine Citation:
PMID:  25194024     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abnormal splice-out of the exon 7-encoded segment in the N-terminal variable region of cardiac troponin T (cTnT-ΔE7) was found in turkeys and, together with the inclusion of embryonic exon (eTnT), in adult dogs with a correlation with dilated cardiomyopathy. Overexpression of these cTnT variants in transgenic mouse hearts significantly decreased cardiac function. To further investigate the functional effect of cTnT-ΔE7 or ΔE7+eTnT in vivo under systemic regulation, echocardiography was carried out in single and double-transgenic mice. No atrial enlargement, ventricular hypertrophy or dilation was detected in the hearts of 2-month-old cTnT-ΔE7 and ΔE7+eTnT mice in comparison to wild-type controls, indicating a compensated state. However, left ventricular fractional shortening and ejection fraction were decreased in ΔE7 and ΔE7+eTnT mice, and the response to isoproterenol was lower in ΔE7+eTnT mice. Left ventricular outflow tract velocity and gradient were decreased in the transgenic mouse hearts, indicating decreased systolic function. Ex vivo working heart function showed that high afterload or low preload resulted in more severe decreases in the systolic function and energetic efficiency of cTnT-ΔE7 and ΔE7+eTnT hearts. On the other hand, increases in preload demonstrated preserved Frank-Starling responses and minimized the loss of cardiac function and efficiency. The data demonstrate that the N-terminal variable region of cardiac TnT regulates systolic function of the heart.
Han-Zhong Feng; Guozhen Chen; Changlong Nan; Xupei Huang; Jian-Ping Jin
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Publication Detail:
Type:  Journal Article     Date:  2014-09-04
Journal Detail:
Title:  Physiological reports     Volume:  2     ISSN:  2051-817X     ISO Abbreviation:  Physiol Rep     Publication Date:  2014 Sep 
Date Detail:
Created Date:  2014-09-06     Completed Date:  2014-09-06     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101607800     Medline TA:  Physiol Rep     Country:  United States    
Other Details:
Languages:  eng     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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