title: Mechanical function and fatty acid oxidation in the neonatal pig heart with ischemia and reperfusion.
abstract: We investigated mechanical function and exogenous fatty acid oxidation in neonatal pig hearts subjected to ischemia, followed by reperfusion. Isolated, isovolumically-beating hearts, from pigs 12 h to 2 days of age, were perfused with an erythrocyte-enriched (hematocrit approximately 15%) solution (37 degrees C). All hearts were studied for 30 min. with a perfusion pressure of 60 mmHg (pre-ischemia). One group of hearts (low-flow ischemia, N = 12) was then perfused for 30 min. with a perfusion pressure of approximately 12 mmHg. In the other group (no-flow ischemic arrest, N = 9), the perfusion pressure was zero for 30 min. Following ischemia in both groups, the perfusion pressure was restored to 60 mmHg for 40 min. (reperfusion). Pre-ischemia parameters for all hearts averaged: left ventricular peak systolic pressure, 99.0 +/- 2.0 mmHg; end diastolic pressure, 1.9 +/- 0.2 mmHg; coronary flow, 3.4 +/- 0.1 ml/min per g; myocardial oxygen consumption, 56.6 +/- 1.6 microliter/min per g and fatty acid oxidation, 33.4 +/- 1.4 nmol/min per g. During low-flow ischemia, hearts released lactate, and the corresponding parameters decreased to: 30.7 +/- 0.9 mmHg; 1.2 +/- 0.3 mmHg; 0.8 +/- 0.1 ml/min per g; 26.6 +/- 2.3 microliters/min per g and 12.9 +/- 1.1 nmol/min per g, respectively. Early in reperfusion in both groups, all parameters, except for fatty acid oxidation, exceeded pre-ischemia values, before recovering to near pre-ischemia values. Late in reperfusion, however, rates of fatty acid oxidation exceeded pre-ischemia rates by approximately 60%. Thus, the neonatal pig heart demonstrated similar recovery following 30 min of low-flow ischemia or no-flow ischemic arrest.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Tulane University School of Medicine, Department of Pediatrics, New Orleans, Louisiana 70112.
authors.forename: R J
authors.initials: RJ
authors.lastname: Ascuitto
authors.forename: N T
authors.initials: NT
authors.lastname: Ross-Ascuitto
authors.forename: D
authors.initials: D
authors.lastname: Ramage
authors.forename: K H
authors.initials: KH
authors.lastname: McDonough
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure; D003326:Coronary Circulation; D003971:Diastole; D005227:Fatty Acids / Q000378:metabolism*; D006321:Heart / Q000503:physiopathology*; D006331:Heart Diseases / Q000378:metabolism / Q000503:physiopathology*; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism; D013552:Swine; D013599:Systole
chemical_list: D005227:Fatty Acids; D007773:Lactates; D010169:Palmitic Acids; D019308:Palmitic Acid; D019344:Lactic Acid; D010100:Oxygen