Lipids, Lipoproteins and Apolipoproteins AIAII, B, CII, CIIIand E in Newborns

In this study lipid and apolipoprotein patterns were investigated at birth and compared with those of adults. In cord sera, cholesterol, triglycerides, low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol were 38.2, 46.2, 50.5, and 31.9%, respectively, of adult values. Apolipoprotein A_II, B and C_III were 48.6, 30.6 and 44.5% of adult values, while apo A_I, apo C_II and apo E showed values approaching those of adults (63.4, 73.3 and 89.7%, respectively). Also cholesterol/HDL cholesterol and LDL cholesterol/HDL cholesterol ratios were lower in newborns. In cord sera, lipids were correlated with various apolipoproteins in a surprisingly different way from adult sera. HDL cholesterol was not inversely correlated with triglycerides, and showed a highly positive correlation with apo E, apo C_II and apo C_III, which did not correlate with HDL cholesterol in adults. These data supported the presence of significant differences in plasma concentrations and composition of lipoproteins at birth. Therefore HDL, apo C_II, and apo E seem to play a different and more important metabolic role in neonatal lipid metabolism.