Document Detail


Accelerated recovery of postischemic stunned myocardium after induced expression of myocardial heat-shock protein (HSP70).
MedLine Citation:
PMID:  7715224     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In vitro studies suggest that interventions targeted at myocardial gene regulation of endogenous cytoprotective elements, such as heat-shock protein, may attenuate myocardial ischemic injury. We tested the hypothesis that heat shock-induced expression of myocardial heat-shock protein before ischemia accelerates functional recovery of postischemic stunned myocardium in the intact circulation. Sixteen dogs underwent partial femoral arteriovenous bypass and core temperature was raised to 42 degrees C for 15 minutes in eight dogs (heat-shocked) and maintained at 37 degrees C in eight dogs (nonheat-shocked). After 24 hours dogs were studied to measure myocardial segment length in the circumflex artery region with ultrasonic dimension transducers, left ventricular pressure with a micromanometer, and circumflex coronary flow with an ultrasonic probe. Regional contractile function was quantified by the area beneath the linear preload recruitable stroke work relationship at baseline and at intervals during reperfusion after a 15-minute circumflex artery occlusion followed by 3 hours of reperfusion. Baseline and peak reperfusion hyperemic circumflex flows were 37 +/- 9 ml/min and 154 +/- 33 ml/min, respectively, in heat-shocked dogs (p < 0.001) and 46 +/- 24 ml/min and 171 +/- 57 ml/min, respectively, in nonheat-shocked dogs (p < 0.001), with no differences between groups (p = not significant) at any time during reperfusion. Heart rate and left ventricular peak pressure, end-diastolic pressure, and first derivative of left ventricular pressure were similar (all p = not significant) in heat-shocked and nonheat-shocked dogs during ischemia and reperfusion. Before ischemia, preload recruitable stroke work relationship did not differ (p = not significant) in heat-shocked and nonheat-shocked dogs. Ischemia reduced preload recruitable stroke work relationship to 32% +/- 8% control (p < 0.001) in heat-shocked dogs and to 19% +/- 15% control in nonheat-shocked dogs (p < 0.001) at 15 minutes of reperfusion, indicating a similar (p = not significant) initial degree of injury. During 3 hours of reperfusion, preload recruitable stroke work relationship returned to 80% +/- 38% control in heat-shocked dogs but to only 33% +/- 13% control in nonheat-shocked dogs (p < 0.0001). Myocardial expression of heat-shock protein, quantified by optical densitometry of Western blots using an antibody specific for HSP70, was greater in heat-shocked than in nonheat-shocked dogs (108 +/- 27 versus 71 +/- 14 densitometry units, p < 0.005).(ABSTRACT TRUNCATED AT 400 WORDS)
Authors:
B L Robinson; T Morita; D O Toft; J J Morris
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  109     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  1995 Apr 
Date Detail:
Created Date:  1995-05-17     Completed Date:  1995-05-17     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  753-64     Citation Subset:  AIM; IM    
Affiliation:
Division of Thoracic and Cardiovascular Surgery, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Dogs
HSP70 Heat-Shock Proteins / physiology*
Myocardial Contraction
Myocardial Reperfusion
Myocardial Stunning / physiopathology*,  therapy
Myocardium / chemistry
Stroke Volume
Chemical
Reg. No./Substance:
0/HSP70 Heat-Shock Proteins

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


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