Plasma ADMA concentrations at birth and mechanical ventilation in preterm infants: a prospective pilot study.
BACKGROUND
Nitric oxide (NO) produced in the lung is an important mediator of normal lung development, vascular smooth muscle relaxation, and ventilation perfusion matching. NO is synthesized from arginine by the action of NO-synthase (NOS). Asymmetric dimethylarginine (ADMA), an endogenous derivate of arginine, inhibits NOS and is thereby a determinant of NO synthesis. We compared ADMA and arginine levels in preterm infants requiring mechanical ventilation with preterm infants who did not require mechanical ventilation and determined the relation between ADMA and the length of mechanical ventilation in these infants.


METHODS
Thirty preterm infants, mean (SD) gestational age 29.3 (1.7) weeks and birth weight 1,340 (350) gram, of the Neonatal Intensive Care Unit of the VU University Medical Center were included. ADMA and arginine were measured in umbilical cord blood and the length of mechanical ventilation (days) was registered.


RESULTS
Gestational age and birth weight were significantly smaller in infants requiring mechanical ventilation, but were not significantly correlated with plasma ADMA concentration after birth. Plasma ADMA concentrations were significantly higher in infants who required mechanical ventilation than in infants who did not require mechanical ventilation (1.53 +/- 0.23 and 1.37 +/- 0.14 micromol/L, respectively; P = 0.036). ADMA concentration was significantly related to length of mechanical ventilation (B = 3.4; 95% CI: 1.1-5.6; P = 0.006), also after adjustment for gestational age (B = 2.3; 95% CI: 0.4-4.2; P = 0.024).


CONCLUSIONS
Preterm infants who require mechanical ventilation have increased ADMA levels compared to non-ventilated preterm infants. ADMA levels at birth are related to the length of mechanical ventilation. An increased ADMA concentration could reduce NO synthesis, which could lead to insufficient gas exchange and, consequently, a longer period of mechanical ventilation.
Richir
Milan C
MC
Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands.
van Leeuwen
Paul A M
PA
van den Berg
Anemone
A
Wessels
Ronni
R
Twisk
Jos W R
JW
Rauwerda
Jan A
JA
Teerlink
Tom
T
de Vries
Theo P G M
TP
van Elburg
Ruurd M
RM
D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010865:Pilot Projects; D047928:Premature Birth / Q000097:blood*; D011446:Prospective Studies; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000097:blood* / Q000628:therapy*; D013997:Time Factors
C018524:N,N-dimethylarginine; D001120:Arginine; D019001:Nitric Oxide Synthase