Surfactant protein A and saturated phosphatidylcholine in respiratory distress syndrome.
We measured surfactant protein A (SP-A) by ELISA using a rabbit antihuman SP-A polyclonal antibody and saturated phosphatidylcholine (SPC) by thin-layer chromatography in sequential tracheal fluid samples obtained from 16 preterm neonates without lung disease and 37 with respiratory distress syndrome (RDS). SP-A and SPC were lower in neonates with RDS than in control infants (1.0 +/- 0.1 versus 8.9 +/- 2.2 ng SP-A/microgram protein [p < 0.0001] and 0.20 +/- 0.05 versus 0.70 +/- 0.19 mumol SPC/mg protein [p < 0.01], respectively). Initial SP-A concentrations correlated inversely with severity of RDS (r = 0.45, p < 0.01) but did not correlate with initial SPC levels. Significant increases in SP-A were detectable within 12 to 24 h after birth in neonates with RDS. Further increases occurred subsequently and were similar for neonates treated with either a synthetic (Exosurf) or a modified natural (Survanta) surfactant. Using two-dimensional gel electrophoresis, SP-A in tracheal fluid obtained during the early and recovery phases of RDS exhibited lesser degrees of posttranslational modification than SP-A forms from control neonates. Administration of Exosurf or Survanta resulted in comparable increases in SPC in tracheal fluid. Preterm neonates with RDS seem to have an immature SP-A metabolism that persists for several days after birth. The type of surfactant used does not modify the recovery of SP-A or SPC in tracheal fluid from infants with RDS.
Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas 75235.
F R
FR
Moya
H F
HF
Montes
V L
VL
Thomas
A M
AM
Mouzinho
J F
JF
Smith
C R
CR
Rosenfeld
D000704:Analysis of Variance; D005260:Female; D006023:Glycoproteins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D010713:Phosphatidylcholines / Q000032:analysis / Q000378:metabolism*; D011510:Proteolipids / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000008:administration & dosage / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy / Q000378:metabolism*; D018709:Statistics, Nonparametric; D013997:Time Factors; D014132:Trachea / Q000378:metabolism
D006023:Glycoproteins; D010713:Phosphatidylcholines; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants