Lactate improves cardiac efficiency after hemorrhagic shock

Jeffrey A. Kline, Lisa R. Thornton, Gary D. Lopaschuk, R. Wayne Barbee, John A. Watts

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

This study was undertaken to examine the role of lactate on cardiac function and metabolism after severe acute hemorrhagic shock. Anesthetized, nonheparinized rats were bled to a mean arterial pressure of 25-30 mm Hg for 1 h; controls were not bled. Their hearts were removed, and cardiac work and efficiency (work/oxygen consumption) were measured in the isolated working heart mode for 60 min. The hearts were perfused with one of five substrate combinations: 1) glucose (11 mM), 2) glucose + 0.4 mM palmitate, 3) glucose + 0.4 mM palmitate + 8.0 mM lactate, 4) glucose + 1.2 mM palmitate, or 5) glucose + 1.2 mM palmitate + 8.0 mM lactate. After perfusion, hearts were freeze-clamped, and tissue contents of free coenzyme-A (CoA), acetyl CoA, and succinyl CoA were measured, as was myocardial pyruvate dehydrogenase (PDH) activity. The addition of 8.0 mM lactate significantly improved cardiac work in shocked hearts perfused with 0.4 mM palmitate and increased cardiac efficiency in the presence of either 0.4 mM or 1.2 mM palmitate. Compared to control hearts, shocked hearts exhibited a 20-30% decrease in PDH activity. Shocked hearts perfused with lactate demonstrated no increase in acetyl CoA content but did have a significant increase in tissue succinyl CoA compared to control hearts perfused with lactate or shocked hearts perfused without lactate. In the heart recovering from severe hemorrhagic shock, lactate improves cardiac efficiency in the presence of free fatty acids, possibly by a anaplerosis of the tricarboxylic acid cycle.

Original languageEnglish (US)
Pages (from-to)215-221
Number of pages7
JournalShock
Volume14
Issue number2
DOIs
StatePublished - Aug 2000
Externally publishedYes

Keywords

  • Cardiac efficiency
  • Fatty acids
  • Hemorrhage
  • Lactate
  • Myocardial metabolism
  • Shock
  • Trauma
  • Tricarboxylic acid cycle

ASJC Scopus subject areas

  • Emergency Medicine
  • Critical Care and Intensive Care Medicine

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  • Cite this

    Kline, J. A., Thornton, L. R., Lopaschuk, G. D., Barbee, R. W., & Watts, J. A. (2000). Lactate improves cardiac efficiency after hemorrhagic shock. Shock, 14(2), 215-221. https://doi.org/10.1097/00024382-200014020-00023