Document Detail


Cardioprotection by postconditioning in conscious rats is limited to coronary occlusions <45 min.
MedLine Citation:
PMID:  16815986     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: Brief episodes of ischemia and reperfusion after a lethal ischemic insult confer cardioprotection, a phenomenon termed "ischemic postconditioning." However, all studies reported to date have been conducted in open-chest animal models. We sought to determine whether postconditioning occurs in conscious animals and whether it protects against severe myocardial injury.
METHODS: Chronically instrumented rats were assigned to a 30- (Subset 1), 45- (Subset 2), or 60-min (Subset 3) coronary occlusion followed by 24 h of reperfusion. In each subset, rats received no further intervention (control), were preconditioned with 12 cycles of 2-min occlusion/2-min reperfusion immediately (early preconditioning; EPC) or 24 h (late preconditioning; LPC) before myocardial infarction, or were postconditioned with 20 cycles of 10-s occlusion/10-s reperfusion immediately after myocardial infarction (20-10 PostC).
RESULTS: With a 30-min occlusion, infarct size (54.4 +/- 2.3% of risk region in control-30) was significantly reduced in EPC-30, LPC-30, and 20-10 PostC-30 groups (by 72, 70, and 47%, respectively; all P < 0.05 vs. control-30). With a 45-min occlusion, infarct size (62.2 +/- 2.4% in control-45) was reduced in EPC-45 and LPC-45 groups (by 47 and 41%, respectively; all P < 0.05 vs. control-45) but not in the 20-10 PostC-45 group [55.4 +/- 2.3%, P = not significant (NS) vs. control-45]. With a 60-min occlusion, infarct size (72.7 +/- 2.2% in control-60) was reduced in the EPC-60 (by 20%, P < 0.05) but not in the LPC-60 (63.6 +/- 2.5%, P = NS) or in the 20-20 PostC group (71.5 +/- 3.4%, P = NS).
CONCLUSIONS: Both early and late ischemic preconditioning as well as ischemic postconditioning confer protection in conscious rats; however, unlike early preconditioning, postconditioning protects only against coronary occlusions <45 min. In the conscious rat, the cardioprotection afforded by postconditioning is limited to mild to moderate myocardial injury.
Authors:
Xian-Liang Tang; Hiroshi Sato; Sumit Tiwari; Buddhadeb Dawn; Qiuli Bi; Qianhong Li; Gregg Shirk; Roberto Bolli
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-06-30
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  291     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2006 Nov 
Date Detail:
Created Date:  2006-10-10     Completed Date:  2007-01-12     Revised Date:  2013-09-05    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2308-17     Citation Subset:  IM    
Affiliation:
Division of Cardiology, Univ. of Louisville, Louisville, KY 40202, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Consciousness
Coronary Disease / physiopathology*,  prevention & control*
Creatine Kinase / blood
Electrocardiography
Ischemic Preconditioning, Myocardial*
Male
Myocardial Infarction / pathology,  prevention & control
Myocardial Reperfusion
Random Allocation
Rats
Rats, Inbred F344
Time Factors
Grant Support
ID/Acronym/Agency:
P01 HL078825/HL/NHLBI NIH HHS; R01 HL055757/HL/NHLBI NIH HHS; R01 HL068088/HL/NHLBI NIH HHS; R01 HL070897/HL/NHLBI NIH HHS; R01 HL074351/HL/NHLBI NIH HHS; R01 HL076794/HL/NHLBI NIH HHS; R01-HL-55757/HL/NHLBI NIH HHS; R01-HL-68088/HL/NHLBI NIH HHS; R01-HL-70897/HL/NHLBI NIH HHS; R01-HL-74351/HL/NHLBI NIH HHS; R01-HL-76794/HL/NHLBI NIH HHS; R01-HL-78825/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
EC 2.7.3.2/Creatine Kinase
Comments/Corrections

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