Erythrocyte lipids in the neonate.

Abstract

Extract: The lipid composition has been characterized in erythrocytes obtained from the cord blood of fullterm normal infants. There is an increase in total lipid, lipid phosphorous and cholesterol per cell (total lipid = 6.45 × 10 -10 mg; Lipid P = 1.54 × 10 -11mg; cholesterol = 1.79 × 10 -10 mg) when compared with adult controls (total lipid = 5.07 × 10 -10 mg; Lipid P = 1.22 × 10 -11mg; cholesterol = 1.33 × 10 -10mg). Despite the increased lipid content, the percentages of total lipid comprised by lipid phosphorous and cholesterol are similar to those found in the adult (P = 2.40% of total lipid in infants, 2.41% in adults: cholesterol = 27.1% of total lipid in infants, 26.0% in adults). Phospholipid fractionation shows minor variations between the two groups. Cord blood erythrocyte phospholipid has 1.0% lysolecithin, 26.0% sphingomyelin, 27.7% phosphatidylcholine, 15.2% combined phosphatidylserine and phosphatidylinositol, and 29.1% phosphatidylethanolamine. Adult erythrocyte phospholipid has 1.2% lysolecithin, 24.1% sphingomyelin, 29.5% phosphatidylcholine, 13.1% combined phosphatidylserine and phosphatidylinositol and 31.2% phosphatidylethanolamine. Phospholipid fatty acid patterns in cord blood erythrocytes show an increased percentage of palmitic acid (cord = 21.3%, adult = 17.0%), stearic acid (cord = 16.3%, adult = 15.3%) arachidonic acid (cord = 19.6%, adult = 17.4%) and combined 22 and 24 carbon fatty acids (cord = 17.6%, adult = 16.3%) associated with decreased percentages of oleic acid (cord = 11.9%, adult = 14.6%) and linoleic acid (cord = 3.4%, adult = 10.9%).Speculation: The erythrocyte lipids of the newborn show deviations from the adult pattern which may have adaptive value for intrauterine life. These same adaptations may render the cell more vulnerable to oxidative damage in postnatal life.