title: In vivo effect of pneumonia on surfactant disaturated-phosphatidylcholine kinetics in newborn infants.
abstract: BACKGROUND
  Bacterial pneumonia in newborns often leads to surfactant deficiency or dysfunction, as surfactant is inactivated or its production/turnover impaired. No data are available in vivo in humans on the mechanism of surfactant depletion in neonatal pneumonia. We studied the kinetics of surfactant's major component, disaturated-phosphatidylcholine (DSPC), in neonatal pneumonia, and we compared our findings with those obtained from control newborn lungs.
  
  
  METHODS
  We studied thirty-one term or near-term newborns (gestational age 39.7±1.7 weeks, birth weight 3185±529 g) requiring mechanical ventilation. Fifteen newborns had pneumonia, while 16 newborns were on mechanical ventilation but had no lung disease. Infants received an intratracheal dose of 13C labeled dipalmitoyl-phosphatidylcholine at the study start. We measured the amount and the isotopic enrichment of DSPC-palmitate from serial tracheal aspirates by gas chromatography and gas chromatography-mass spectrometry, respectively, and we calculated the DSPC half-life (HL) and pool size (PS) from the isotopic enrichment curves of surfactant DSPC-palmitate.
  
  
  RESULTS
  The mean DSPC amount obtained from all tracheal aspirates did not differ between the two groups. DSPC HL was 12.7 (6.5-20.2) h and 25.6 (17.9-60.6) h in infants with pneumonia compared with control infants (p = 0.003). DSPC PS was 14.1 (6.6-30.9) mg/kg in infants with pneumonia and 34.1 (25.6-65.0) mg/kg in controls, p = 0.042. Myeloperoxidase (MPO) activity, as a marker of lung inflammation, was 1322 (531-2821) mU/ml of Epithelial Lining Fluid (ELF) and 371(174-1080) mU/ml ELF in infants with pneumonia and in controls, p = 0.047. In infants with pneumonia, DSPC PS and HL significantly and inversely correlated with mean Oxygenation Index (OI) during the study (DSPC PS vs. OI R = -0.710, p = 0.004 and HL vs. OI R = -0.525, p = 0.044, respectively).
  
  
  CONCLUSIONS
  We demonstrated for the first time in vivo in humans that DSPC HL and PS were markedly impaired in neonatal pneumonia and that they inversely correlated with the degree of respiratory failure.
authors.affiliation: Department of Women's and Children's Health, University of Padua, Padua, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Facco
authors.affiliation: Neonatal Medicine, Salesi Children's Hospital, Polytechnic University of Marche and University of Ancona, Ancona, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Nespeca
authors.affiliation: Department of Women's and Children's Health, University of Padua, Padua, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Simonato
authors.affiliation: Department of Women's and Children's Health, University of Padua, Padua, Italy.
authors.forename: Ilena
authors.initials: I
authors.lastname: Isak
authors.affiliation: Department of Women's and Children's Health, University of Padua, Padua, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Verlato
authors.affiliation: Neonatal Medicine, Salesi Children's Hospital, Polytechnic University of Marche and University of Ancona, Ancona, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ciambra
authors.affiliation: Neonatal Medicine, Salesi Children's Hospital, Polytechnic University of Marche and University of Ancona, Ancona, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Giorgetti
authors.affiliation: Neonatal Medicine, Salesi Children's Hospital, Polytechnic University of Marche and University of Ancona, Ancona, Italy.
authors.forename: Virgilio P
authors.initials: VP
authors.lastname: Carnielli
authors.affiliation: Pediatric Cardiac Anesthesia/Intensive Care Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital, Rome, Italy.
authors.forename: Paola E
authors.initials: PE
authors.lastname: Cogo
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000008:administration & dosage / Q000493:pharmacokinetics; D016022:Case-Control Studies; D064907:Diagnostic Uses of Chemicals; D005260:Female; D005865:Gestational Age; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000378:metabolism; D008297:Male; D009195:Peroxidase / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism*; D011014:Pneumonia / Q000378:metabolism* / Q000628:therapy; D011446:Prospective Studies; D012121:Respiration, Artificial
chemical_list: D064907:Diagnostic Uses of Chemicals; D010713:Phosphatidylcholines; C017463:lecithins, disaturated; D015060:1,2-Dipalmitoylphosphatidylcholine; D009195:Peroxidase