Polymorphism of human plasma apolipoprotein C-III at birth and in early neonatal life

Abstract

Studies were carried out to investigate potential changes in apolipoprotein C-III (apoC-III) polymorphism from birth through the first month of life. Maternal serum at term and neonatal serum at birth, 3, 14, and 28 days were analyzed for the three principal polymorphic forms of apoC-III: apoC-III-0, apoC-III-1, and apoC-III-2. A two-dimensional electrophoretic procedure combining isoelectric focusing and electroimmunoassay was developed for this purpose. In maternal serum (n = 28), apoC-III-1 to apoC-III-2 ratios (1.45) were typical of normolipidemic adult serum, while the corresponding cord sera (n = 32) had a reversal of the apoC-III-1 to apoC-III-2 ratio (0.55). Basic polyacrylamide gel electrophoretic patterns of isolated cord sera lipoprotein density classes confirmed the reversal of the apoC-III-1 to apoC-III-2 ratio in each class. Following birth, the apoC-III-1 to apoC-III-2 ratio reached unity (1.04) at 3 days and did not change significantly thereafter. It can be concluded that the apoC-III-1 to apoC-III-2 ratio in the normal newborn increases shortly after birth primarily due to an increase in apoC-III-1, and this change appears to be associated with oral feeding, suggesting that intestinal factors may play a role in controlling the ratio of plasma apoC-III-1 to apoC-III-2.