Document Detail


Developmental changes in tolerance to ischaemia in the rabbit heart: disparity between interpretations of structural, enzymatic and functional indices of injury.
MedLine Citation:
PMID:  1479615     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The vulnerability of the heart to injury during ischaemia and reperfusion and its responsiveness to various protective and pharmacological interventions are age-dependent. Using three independent indices of tissue injury (cardiac structure, contractile function and creatine kinase leakage), we compared the response of adult (60-90 days old) and neonatal (7 days old) isolated perfused rabbit hearts to global ischaemia and reperfusion. Prior to ischaemia, heart rate was significantly higher in neonatal hearts, as were control values for coronary flow, aortic flow and cardiac output when expressed on a dry wt basis. In experiments in which adult and neonatal hearts (n = 8 per group) were subjected to 2 min of cardioplegia and 45 min of ischaemia, the post-ischaemic recovery of all indices of cardiac function (when expressed as a percentage of pre-ischaemic control) was significantly higher in neonatal than in adult hearts. Thus, cardiac output recovered to 82.9 +/- 3.6% in the neonate but to only 57.9 +/- 6.7% in the adult (P < 0.05). The functional evidence of a greater resistance to ischaemia in the neonate was, however, contradicted by the levels of creatine kinase leakage which tended to be greater in the neonatal than in the adult heart (32.0 +/- 4.7 vs 20.0 +/- 3.1 IU/15 min/g dry wt). Morphological studies indicated that injury was comparable (moderate-to-severe in degree) in both groups. To assess further the relationship between the three indices, additional experiments were undertaken in which the duration of ischaemia in the neonate was extended to 60 min so that the post-ischaemic recovery of function was reduced to a level similar to that seen in the adult after 45 min of ischaemia. Under these conditions cardiac output recovered to 55.6 +/- 4.8% in the neonatal heart (P = NS when compared with the adult) and creatine kinase leakage increased to 88.2 +/- 13.9 IU/15 min/g dry wt--a value over four times greater than that measured in adult hearts with a comparable degree of functional injury. Morphological examination of tissue obtained after 15 min of reperfusion revealed a remarkable recovery of structure in both age groups. In conclusion, in functional terms the neonatal heart was more resistant to ischaemia than the adult; enzymic leakage, however, indicated the opposite and structural assessment revealed no differences. Thus, in comparing injury during ischaemia and reperfusion between different age groups, it is clearly important to employ several independent indices.
Authors:
T Murashita; M Borgers; D J Hearse
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of molecular and cellular cardiology     Volume:  24     ISSN:  0022-2828     ISO Abbreviation:  J. Mol. Cell. Cardiol.     Publication Date:  1992 Oct 
Date Detail:
Created Date:  1993-02-11     Completed Date:  1993-02-11     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0262322     Medline TA:  J Mol Cell Cardiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1143-54     Citation Subset:  IM    
Affiliation:
Cardiovascular Research, Rayne Institute, St. Thomas' Hospital, London, UK.
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MeSH Terms
Descriptor/Qualifier:
Age Factors
Animals
Animals, Newborn
Cardiac Output
Creatine Kinase / analysis*
Heart / physiopathology
Heart Rate
Myocardial Ischemia / metabolism,  physiopathology*
Myocardial Reperfusion Injury / metabolism,  physiopathology*
Myocardium / pathology
Rabbits
Grant Support
ID/Acronym/Agency:
HL 39457/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
EC 2.7.3.2/Creatine Kinase

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


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