title: Umbilical vein plasma concentrations of asymmetrical dimethylarginine are increased in male but not female neonates delivered preterm: a pilot study.
abstract: BACKGROUND
  Infants born term have substantially elevated plasma concentrations of the endogenous nitric oxide synthase antagonist asymmetrical dimethylarginine (ADMA) that normalize with growth. The plasma levels of ADMA in preterm newborns are unknown.
  
  
  METHODS
  Plasma concentrations of ADMA, symmetrical dimethylarginine (SDMA) and L-arginine were analyzed from venous umbilical cord blood samples of 19 preterm and 21 term infants by high performance liquid chromatography.
  
  
  RESULTS
  Male preterm newborns (n=11) had higher ADMA (median [95% confidence interval (CI)]: 1.90 [1.73-2.10] micromol/l) than females born preterm (n=8; 1.57 [1.24-1.69] micromol/l; p<0.005). In term born males (n=10) and females (n=11) ADMA was significantly lower than in preterm male infants (all p<0.005), and without sex differences. SDMA and L-arginine concentrations were comparable between all groups. ADMA correlated inversely with body weight in male preterm newborns (r=-0.67; p<0.03).
  
  
  CONCLUSIONS
  Male neonates delivered preterm have significantly higher umbilical cord venous plasma concentrations of ADMA compared to female neonates and infants born term. The sex difference and the time course of elevated ADMA may play a role in development and warrant further investigation.
authors.affiliation: Department of Clinical Pharmacology, Medical University Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Mittermayer
authors.forename: Andrea-Romana
authors.initials: AR
authors.lastname: Prusa
authors.forename: Arnold
authors.initials: A
authors.lastname: Pollak
authors.forename: Michael
authors.initials: M
authors.lastname: Wolzt
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000502:physiology; D001775:Blood Circulation / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D008297:Male; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010865:Pilot Projects; D047928:Premature Birth / Q000097:blood*; D012727:Sex Characteristics; D013997:Time Factors
chemical_list: C487735:dimethylarginine; C018524:N,N-dimethylarginine; D001120:Arginine; D019001:Nitric Oxide Synthase