Document Detail


Chronic hypoxia induces adaptive metabolic changes in neonatal myocardium.
MedLine Citation:
PMID:  8691889     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effect of chronic hypoxia on neonatal myocardial metabolism remains undefined. With a new neonatal piglet model, we determined changes in myocardial metabolism during global ischemia after chronic hypoxia. Five-day-old piglets (N = 30) were randomly assigned to two groups and exposed to an atmosphere of 8% oxygen or to room air for 28 days before they were killed. Left ventricular myocardium was then analyzed at control and at 15-minute intervals during 60 minutes of global normothermic ischemia to determine high-energy phosphate levels, glycogen stores, and lactate accumulation. Time to peak ischemic myocardial contracture was measured with intramyocardial needle-tipped Millar catheters as a marker of the onset of irreversible ischemic injury. Results showed an initially greater level of myocardial adenosine triphosphate in the hypoxic group (27 +/- 1.2 vs 19 +/- 1.8 micromol/gm dry wt, p = 0.001) and a delay in adenosine triphosphate depletion during 60 minutes of global ischemia compared with the control group. Initial energy charge ratios (1/2 adenosine diphosphate + adenosine triphosphate/adenosine monophosphate + adenosine diphosphate + adenosine triphosphate) were also greater in the hypoxic group (0.96 +/- 0.01 vs 0.81 +/- 0.04, p = 0.01) and remained so throughout global ischemia. Initial glycogen stores were greater in the hypoxic group (273 +/- 13.3 vs 215 +/- 14.7 micromol/gm dry weight, p = 0.02) when compared with the control group. Lactate levels in the hypoxic group were initially higher (19.1 +/- 6.4 vs 8.9 +/- 3.1 micromol/gm dry weight, p = 0.001) compared with control levels and remained elevated throughout 60 minutes of ischemia. Time to peak ischemic contracture was prolonged in the hypoxic group (69.5 +/- 1.8 vs 48.9 +/- 1.4 minutes, p = 0.001) compared with the controls group. These data show that chronic hypoxia results in significant myocardial metabolic adaptive changes, which in turn result in an improved tolerance to severe normothermic ischemia. These beneficial effects are associated with elevated baseline glycogen storage levels and an accelerated rate of anaerobic glycolysis during ischemia.
Authors:
M D Plunkett; P J Hendry; M P Anstadt; E M Camporesi; M T Amato; J D St Louis; J E Lowe
Related Documents :
17347689 - Newborn hearts are at greater 'metabolic risk' during global ischemia--advantages of co...
3753389 - Evidence against systolic intramural forces as the primary cause of subendocardial prep...
12384479 - Transmural reentry triggered by epicardial stimulation during acute ischemia in canine ...
1999619 - Perioperative myocardial ischemia in patients undergoing noncardiac surgery--ii: incide...
2450489 - Histochemical and fluorescent techniques for detection of early myocardial ischemia fol...
9244239 - Acute ischemic ventricular arrhythmias in pigs with healed myocardial infarction: compa...
6127349 - Ventricular antiarrhythmic effects of beta-adrenergic blocking drugs: a review of mecha...
8783909 - Premature myocardial infarction in singapore--risk factor analysis and clinical features.
21251629 - Persistent coronary no flow after wire insertion is an early and readily available mort...
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  112     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  1996 Jul 
Date Detail:
Created Date:  1996-08-23     Completed Date:  1996-08-23     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  8-13     Citation Subset:  AIM; IM    
Affiliation:
Department of Surgery, Duke University Medical Center, Durham, NC, USA.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn
Anoxia / metabolism*
Chronic Disease
Disease Models, Animal
Glycogen / analysis
Myocardial Contraction
Myocardium / chemistry,  metabolism*
Swine
Ventricular Function, Left*
Grant Support
ID/Acronym/Agency:
HL-17670/HL/NHLBI NIH HHS; HL07819-02/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
9005-79-2/Glycogen

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


Previous Document:  External stenting reduces early medial and neointimal thickening in a pig model of arteriovenous byp...
Next Document:  Effects of inflation volume during lung preservation on pulmonary capillary permeability.