Fatty acid composition of phospholipids in erythrocytes of adults, normal newborn infants, and neonates with Rh erythroblastosis.

Abstract

Extract: The fatty acid patterns of the total phospholipids (PL) and the individual PL, namely phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl serine (PS), and sphingomyelin (SP), in erythrocytes from five adults, five healthy newborn infants, and four neonates with Rh erythroblastosis were analyzed by gas-liquid chromatography (GLC) after the PL had been separated by thin layer chromatography (TLC). The content of linoleic acid in the total PL in erythrocytes of newborn infants was significantly smaller than in erythrocytes of adults (3.8% versus 11.9% of total fatty acid content). Furthermore, the contents of 20:1n-9, 20:5n-3, and 22:5n-3 were also smaller. The concentrations of the saturated fatty acids 16:0 and 20:0 and of the unsaturated fatty acids 20:3n-9, 22:3n-9, 20:3n-6; 20:4n-6, 22:5n-6, and 22:6n-3 were significantly larger. Within the oleate, linoleate, and linolenate family, there was a shift toward more highly unsaturated fatty acids. Corresponding changes were found in the fatty acid patterns of the individual PL. The fatty acid pattern in erythrocytes from newborn infants resembled that induced by a deficiency of essential fatty acids. The fatty acid pattern of the total PL in erythrocytes from neonates with Rh erythroblastosis corresponded to that of normal newborn infants, whereas there were only slight differences in the fatty acid compositions of the individual PL. Thus, a change in the lipid and fatty acid compositions cannot account for the hemolysis caused by antibodies. Speculation: The pattern of fatty acids of PL in erythrocytes from newborn infants differs from that of adults. The difference is obviously the result of a deficiency of essential fatty acids in the fetus. This lack could be induced by a permeability barrier in the placenta or by insufficient binding of lipids onto the plasma proteins of the fetus. Insufficient uptake of fatty acids by the fetus is recognizable by a decreased content of essential fatty acids, since the other fatty acids can be synthesized de novo by the fetus.