Metabolic substrates can alter postischemic recovery in preconditioned ischemic heart

T. A. Fralix, Charles Jr Steenbergen, R. E. London, E. Murphy

Research output: Contribution to journalArticle

Abstract

The mechanisms that contribute to myocardial cell injury are not well understood. Furthermore, the ability of reperfusion conditions to modify ischemic injury is unclear. Recent studies have indicated that glucose utilization may improve ionic homeostasis. Because considerable derangement of ion concentrations occurs during ischemia, glucose utilization may be beneficial when stimulated during the reperfusion period. The effects of glycolytic vs. mitochondrial substrates on postischemic contractile function, high-energy phosphates and ion balance (intracellular Ca2+ and pH) were determined. Reperfusion conditions were compared in the 'preconditioned ischemic' heart where baseline contractile recovery during reperfusion with glucose as the sole exogenous substrate was 74 ± 5% (n = 10). Contractile recovery was determined for reperfusion with pyruvate (14 ± 2%, n = 10), pyruvate + glucose (23 ± 4%, n = 10), deoxyglucose + acetate (25 ± 4%, n = 10), and lactate + glucose (60 ± 11%, n = 10). Contractile dysfunction could not be attributed to differences in high-energy phosphate contents. Elevated levels of intracellular Ca2+ during reperfusion were, however, correlated with poor contractile function. After 20 min of reperfusion, the mean time- averaged intracellular Ca2+ values, measured with 19F-nuclear magnetic resonance of 5-fluoro-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-loaded hearts, were 994 ± 110 nM (glucose, n = 5), 2,270 ± 494 nM (pyruvate, n = 5), 2,671 ± 419 nM (pyruvate + glucose, n = 5), 2,382 ± 480 nM (deoxyglucose + acetate, n = 5), and 1,019 ± 33 nM (lactate + glucose, n = 5). These results are consistent with a beneficial role for glucose utilization during reperfusion, where enhanced recovery of contractile function and ionic homeostasis were observed.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume263
Issue number1 32-1
StatePublished - 1992
Externally publishedYes

Fingerprint

Reperfusion
Glucose
Recovery
Substrates
Pyruvic Acid
Deoxyglucose
Lactic Acid
Acetates
Homeostasis
Phosphates
Enhanced recovery
Ions
Recovery of Function
Wounds and Injuries
Magnetic Resonance Spectroscopy
Ischemia
Nuclear magnetic resonance

Keywords

  • calcium
  • reperfusion
  • substrates

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Metabolic substrates can alter postischemic recovery in preconditioned ischemic heart. / Fralix, T. A.; Steenbergen, Charles Jr; London, R. E.; Murphy, E.

In: American Journal of Physiology - Cell Physiology, Vol. 263, No. 1 32-1, 1992.

Research output: Contribution to journalArticle

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