Lysophospholipid accumulation has been implicated in the pathogenesis of irreversible injury during
myocardial ischemia and reperfusion.
Plasmalogens (
phospholipids with a
vinyl-ether bond in the sn-1 position) account for more than 50% of total myocardial sarcolemmal and sarcoplasmic reticulum
phospholipids. Accumulation of
plasmalogen choline and
ethanolamine lysophospholipids (
lysoplasmenylcholine and
lysoplasmenylethanolamine) or the effects of exogenous
fatty acids on lysoplasmalogen accumulation during
ischemia and reperfusion have not been examined. Isolated working rat hearts perfused with
buffer containing either 11 mM
glucose or 11 mM
glucose plus 1.2 mM
palmitate were subjected to aerobic, ischemic, or
ischemia/reperfusion protocols. Levels of
lysoplasmenylcholine and
lysoplasmenylethanolamine were quantified using a two-stage high-performance liquid chromatographic technique. In hearts perfused with
glucose alone, no significant differences in levels of
lysoplasmenylcholine or
lysoplasmenylethanolamine were seen during
ischemia or reperfusion. In
fatty acid-perfused hearts, however, significant accumulation of
lysoplasmenylethanolamine occurred during reperfusion but not during
ischemia (723 +/- 112, 734 +/- 83, and 1,394 +/- 193 nmol/g dry wt for aerobic, ischemic, and ischemic/reperfused hearts, respectively; p less than 0.05 for ischemic/reperfused hearts versus aerobic or ischemic hearts).
Lysoplasmenylcholine levels after
ischemia and reperfusion did not differ significantly from aerobic values, regardless of whether
fatty acids were present or absent from the perfusate. Aerobic and ischemic/reperfused rabbit hearts, in the presence of
fatty acid, showed a similar profile in their lysoplasmalogen content. We conclude that differential
lysoplasmenylethanolamine accumulation occurs during myocardial reperfusion when exogenous
fatty acid concentrations are high. This may reflect the selective action of
fatty acid intermediates on the metabolism of lysoplasmenylethanolamines.(ABSTRACT TRUNCATED AT 250 WORDS)