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Title: Effects of Continuous Triiodothyronine Infusion on Citric Acid Cycle in the Normal Immature Swine Heart under Extracorporeal Membrane Oxygenation in vivo

Extracorporeal membrane oxygenation (ECMO) is frequently used in infants with postoperative cardiopulmonary failure. ECMO also suppresses circulating triiodothyronine (T3) levels and modifies myocardial metabolism. We assessed the hypothesis that T3 supplementation reverses ECMO induced metabolic abnormalities in the immature heart. Twenty-two male Yorkshire pigs (age 25-38 days) with ECMO were received [2-13C]lactate, [2,4,6,8-13C]octanoate (medium chain fatty acid) and [U-13C]long-chain fatty acids as metabolic tracers either systemically (totally physiological intracoronary concentration) or directly into the coronary artery (high substrate concentration) for the last 60 minutes of each protocol. Nuclear magnetic resonance (NMR) analysis of left ventricular tissue determined the fractional contribution (Fc) of these substrates to the citric acid cycle (CAC). Fifty percent of the pigs in each group received intravenous T3 supplement (bolus at 0.6 μg/kg and then continuous infusion at 0.2 μg/kg/hour) during ECMO. Under both substrate loading conditions T3 significantly increased lactate-Fc with a marginal increase in octanoate-Fc. Both T3 and high substrate provision increased myocardial energy status indexed by [Phosphocreatine]/[ATP]. In conclusion, T3 supplementation promoted lactate metabolism to the CAC during ECMO suggesting that T3 releases inhibition of pyruvate dehydrogenase. Manipulation of substrate utilization by T3 may be used therapeutically during ECMO to improve resting energy statemore » and facilitate weaning.« less
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [2] ;  [2]
  1. Seattle Children's Research Inst., Seattle, WA (United States)
  2. Seattle Children's Research Inst., Seattle, WA (United States); Univ. of Washington, Seattle, WA (United States)
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0363-6135; 48162; 600306000
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Physiology: Heart and Circulatory Physiology; Journal Volume: 306; Journal Issue: 8
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org:
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES cardiac metabolism; extracorporeal circulation; fatty acids; pediatrics; thyroid hormone; citric acid cycle; Environmental Molecular Sciences Laboratory