Background: Term newborns with pneumonia show a reduced pulmonary compliance due to multiple and ill-defined factors. Surfactant proteins' (SPs) changes could have a role in the reduced compliance but the matter is still unsettled. The aim of this study was to clarify the meaning of SPs changes during pneumonia in term newborns.
Methods: In 28 term ventilated newborns, 13 with pneumonia and 15 with no lung disease, we measured SP-B, SP-A, disaturated-phosphatidylcholine (DSPC), and total phospholipids (PL) concentrations in tracheal aspirates at intubation and close to extubation. We also measured DSPC kinetics using (U-(13)C-PA)dipalmitoyl-phosphatidylcholine.
Results: At baseline, SP-B, expressed as % of PL, was significantly different between the groups, being 3.5-fold higher in pneumonia than controls. Conversely, SP-A did not vary between the groups. At extubation, SP-B and SP-A concentrations had decreased significantly in newborns with pneumonia, while there was no significant change in controls. DSPC t1/2 was significantly shorter in the pneumonia group (11.8 (5.5-19.8) h vs. 26.6 (19.3-63.6) h, P = 0.011).
Conclusion: In term newborns with pneumonia, SP-B increases with respect to PL, and DSPC is turned over at a faster rate. Disease's resolution is associated with the restoration of the normal ratio between SP-B and PL.