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Published on: May 24, 2016
Mechanical function and fatty acid oxidation in the neonatal pig heart with ischemia and reperfusion
R J Ascuitto1, N T Ross-Ascuitto, D Ramage
1Tulane University School of Medicine, Department of Pediatrics, New Orleans, Louisiana 70112.
Insights
Neonatal pig hearts showed similar recovery after low-flow or no-flow ischemia. Fatty acid oxidation significantly increased during reperfusion in both groups.
Area of Science:
- Cardiology
- Neonatal Physiology
- Metabolic Research
Background:
- Neonatal hearts have unique metabolic properties.
- Understanding ischemia-reperfusion injury is crucial for neonatal cardiac care.
Purpose of the Study:
- To investigate mechanical function and fatty acid oxidation in neonatal pig hearts after ischemia-reperfusion.
- To compare the effects of low-flow versus no-flow ischemia on neonatal heart recovery.
Main Methods:
- Isolated, isovolumically-beating neonatal pig hearts were subjected to 30 minutes of either low-flow or no-flow ischemia.
- Mechanical function and exogenous fatty acid oxidation were measured before, during, and after reperfusion.
- Perfusion solutions were erythrocyte-enriched at 37 degrees C.
Main Results:
- Both ischemia types reduced mechanical function and fatty acid oxidation.
- During reperfusion, mechanical parameters initially exceeded pre-ischemia levels before returning to baseline.
- Fatty acid oxidation rates were approximately 60% higher than pre-ischemia levels late in reperfusion for both groups.
Conclusions:
- The neonatal pig heart exhibits comparable recovery from both low-flow and no-flow ischemia.
- Increased fatty acid oxidation during reperfusion suggests a metabolic shift in the recovering neonatal heart.
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)
