DIETARY NUCLEOTIDES ENHANCE PLASMA LECITHIN-CHOLESTEROL ACYL TRANSFERASE-ACTIVITY AND APOLIPOPROTEIN A-IV CONCENTRATION IN PRETERM NEWBORN-INFANTS

The activity of lecithin cholesterol acyl transferase (LCAT), a key en zyme in lipoprotein metabolism, is low in newborn preterm infants. It has been suggested that a normal gastrointestinal function might be ne cessary to induce a postnatal increase of LCAT activity because apopro teins A-I and A-IV (apoA-I and apoA-IV) synthesized in considerable am ounts in the intestine are known activators of LCAT. Dietary nucleotid es have been reported to enhance intestinal growth and maturation; the refore, we hypothesized that nucleotide supplementation to formulas fo r preterm infants may influence LCAT activity. To investigate this hyp othesis, two groups of preterm infants were fed either a nucleotide-fr ee formula or a nucleotide-supplemented formula during the first month of life. The plasma LCAT activity, plasma levels of apoA-I and apoA-I V, plasma cholesteryl esters, and plasma fatty acid composition of cho lesteryl esters and phospholipids were then determined. Infants receiv ing nucleotides had higher LCAT activities and apoA-IV levels than tho se receiving the nucleotide-free formula for a few weeks. The changes in apoA-IV levels were highly correlated with those of the LCAT activi ties. However, there were no significant correlations between changes in LCAT activity and plasma cholesteryl esters or phospholipids. These findings indicate that nucleotide supplementation to formulas for pre term infants may improve dietary lipid tolerance by enhancing plasma L CAT activity, probably as a result of an increase in apoA-IV plasma co ncentrations; they also suggest that nucleotides may enhance apoA-IV s ynthesis in the intestine during the neonatal period.