Elevated malonyldialdehyde levels, altered membrane lipid asymmetry, and hypercoagulability of erythrocytes from newborn infants

Abstract

This study has examined membrane lipid peroxidative damage, phospholipid (PL) organization, and coagulability of red blood cells (RBC) of newborns (N) and adults (A). Peroxidative lipid damage was assessed by quantitating malonyldialdehyde (MDA) by thiobarbituric acid-reactivity and by lipid extract fluorescence. Membrane PL organization was detected by Bee venom phospholipase-A2 (Plase) treatment, which specifically hydrolyzes outer bilayer phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylcholine (PC). Coagulability was measured by Russell's viper venom clotting time. Results show MDA level of 7.47 +/- 0.72 in N-RBC and 3.86 +/- 0.23 nmoles/ml PCV in A-RBC, with relative lipid extract fluorescence of 12 +/- 1 and 9 +/- 1 U respectively. PLase hydrolyzed 63 PC, 9 PE, and 0% PS in A-RBC and 56 PC, 16 PE, and 8% PS in N-RBC, suggesting that a portion of PS is also present in outer bilayer in N-RBC. N-RBC took 16% less time than A-RBC to form a firm fibrin clot on recalcification. This study suggests significantly greater membrane lipid peroxidative damage in the neonatal RBC. Hypercoagulability due to the PS externalization in N-RBC may have a role in the disseminated intravascular coagulation of newborn infants.