Very low-density lipoprotein in the cord blood of preterm neonates

Human fetuses have markedly low levels of serum lipids and a unique lipoprotein profile with respect to quality, with low-density lipoprotein (LDL)-like particle as the dominant cholesterol carrier. However, little is known about triglyceride (TG) distribution. In addition, lipid metabolism is important in lung development, with indications that TG from very low-density lipoprotein (VLDL) is essential for surfactant synthesis. We investigated TG distribution in preterm neonate cord blood and the relationship of VLDL-TG levels with respiratory distress syndrome (RDS). The study included 103 appropriate-for-gestational-age neonates (61 males). We performed serum lipoprotein analyses in cord blood by high-performance liquid chromatography with gel permeation columns. Term neonates had low cord blood TG concentrations distributed equally to the LDL and VLDL fractions. However, preterm neonates had even lower TG concentrations, with VLDL as the dominant carrier. The LDL-TG and high-density lipoprotein-TG concentrations in cord blood increased gradually with gestational age, but cord blood VLDL-TG concentrations increased dramatically from 32 to 34 weeks of gestational age. Neonates with RDS exhibited no RDS-specific lipoprotein profile; however, most were born before the timing of the dramatic VLDL-TG increase. Our results suggest that 34 weeks of gestation is a critical period for TG metabolism, indicating the need for evaluation of the lipid nutritional state in preterm neonates.