IMMEDIATE COMMENCEMENT OF AMINO-ACID SUPPLEMENTATION IN PRETERM INFANTS - EFFECT ON SERUM AMINO-ACID-CONCENTRATIONS AND PROTEIN KINETICS ONTHE FIRST DAY OF LIFE
Jb. Vangoudoever et al., IMMEDIATE COMMENCEMENT OF AMINO-ACID SUPPLEMENTATION IN PRETERM INFANTS - EFFECT ON SERUM AMINO-ACID-CONCENTRATIONS AND PROTEIN KINETICS ONTHE FIRST DAY OF LIFE, The Journal of pediatrics, 127(3), 1995, pp. 458-465
To determine whether the general reluctance to begin amino acid admini
stration to preterm infants from birth onward might lead to loss of le
an body mass and impairment of growth, we measured amino acid levels a
nd protein kinetics in 18 preterm infants, Nine infants received amino
acids (1.15 +/- 0.06 gm . kg(-1). day(-1)) and glucose (6.05 +/- 1.58
gm . kg(-1). day(-1)), whereas the other nine infants received only g
lucose (6.48 +/- 1.30 gm . kg(-1). day(-1)) from birth onward, Protein
kinetics on the first postnatal day were measured with a stable isoto
pe dilution technique with (1-C-13)leucine as a tracer, No statistical
ly significant differences were noted in blood pH, base excess, urea c
oncentration, or glucose levels, Both total amino acid concentration a
nd total essential amino acid concentration were significantly lower a
nd were below the reference range in the nonsupplemented group, Plasma
amino acid levels of five essential amino acids (methionine, cystine,
isoleucine, leucine, arginine) were below the reference range in the
nonsupplemented group, whereas only cystine was below the reference ra
nge in the supplemented group, Nitrogen retention was improved signifi
cantly by the administration of amino acids (-110 +/- 44 mg nitrogen p
er kilogram per day in the glucose-only group vs +10 +/- 127 mg nitrog
en per kilogram per day in the group given glucose and amino acids; p
= 0.001); leucine oxidation was not significantly increased in the sup
plemented group (41 +/- 13 mu mol . kg(-1). hr(-1) vs 46 +/- 16 mu mol
. kg(-1). hr(-1)). Leucine balance also improved significantly (-41 /- 13 mu mol . kg(-1). hr(-1) vs -8 +/- 16 mu mol . kg(-1). hr(-1); p
= 0.01) because of a combination of an increased amount of leucine bei
ng used for protein synthesis and a lower amount of leucine coming fro
m protein breakdown, Plasma cystine concentration, the only amino acid
below the reference range in the supplemented group, was highly predi
ctive for protein synthesis in that group. We conclude that the admini
stration of amino acids to preterm infants from birth onward seems saf
e and prevents the loss of protein mass.