Albumin synthesis in premature neonates is stimulated by parenterally administered amino acids during the first days of life.
BACKGROUND
We recently showed that parenteral administration of amino acids to premature infants immediately after birth is safe and results in a positive nitrogen balance and increased whole-body protein synthesis. However, we did not determine organ-specific effects; albumin, produced by the liver, is an important protein, but its concentration is often low in premature neonates during the first few days after birth.


OBJECTIVE
The objective of the study was to test the hypothesis that the fractional and absolute albumin synthesis rates would increase with the administration of amino acids after birth, even at low nonprotein energy intake.


METHODS
Premature infants (<1500 g birth weight), who were on ventilation, received from birth onward either glucose only (control group, n = 7) or glucose and 2.4 g amino acid kg(-1) d(-1) (intervention group, n = 8). On postnatal day 2, all infants received a primed continuous infusion of [1-(13)C]leucine, and mass spectrometry techniques were used to determine the incorporation of the leucine into albumin. Results are expressed as medians and 25th and 75th percentiles.


RESULTS
Albumin fractional synthesis rates in the intervention group were significantly higher than those in the control group [22.9% (17.6-28.0%)/d and 12.6% (11.0-19.4%)/d, respectively; P = 0.029]. Likewise, the albumin absolute synthesis rates in the intervention group were significantly higher than those in the control group [228 (187-289) mg kg(-1) d(-1) and 168 (118-203) mg kg(-1) d(-1), respectively; P = 0.030].


CONCLUSIONS
Amino acid administration increases albumin synthesis rates in premature neonates even at a low energy intake.
van den Akker
Chris H P
CH
Division of Neonatology, Department of Pediatrics, Erasmus Medical Center-Sophia Children's Hospital, Rotterdam, Netherlands.
te Braake
Frans W J
FW
Schierbeek
Henk
H
Rietveld
Trinet
T
Wattimena
Darcos J L
DJ
Bunt
Jan Erik H
JE
van Goudoever
Johannes B
JB
D000418:Albumins / Q000096:biosynthesis* / Q000187:drug effects / Q000378:metabolism; D000596:Amino Acids / Q000008:administration & dosage*; D002247:Carbon Isotopes; D005260:Female; D005865:Gestational Age; D005947:Glucose / Q000378:metabolism / Q000493:pharmacokinetics; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000378:metabolism*; D007363:Intensive Care Units, Neonatal; D007930:Leucine / Q000378:metabolism / Q000493:pharmacokinetics*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009751:Nutritional Requirements; D009928:Organ Specificity; D010288:Parenteral Nutrition / Q000379:methods*; D013997:Time Factors
D000418:Albumins; D000596:Amino Acids; D002247:Carbon Isotopes; D007930:Leucine; D005947:Glucose