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Phospholipase A 2 is present in meconium and inhibits the activity of pulmonary surfactant: an in vitro study
Author(s) -
Schrama AJJ,
Beaufort AJ,
Sukul YRM,
Jansen SM,
Poorthuis BJHM,
Berger HM
Publication year - 2001
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.2001.tb00442.x
Subject(s) - meconium , pulmonary surfactant , meconium aspiration syndrome , atelectasis , medicine , chromatography , respiratory distress , lung , chemistry , anesthesia , biochemistry , fetus , biology , pregnancy , genetics
Atelectasis, a major contributor to pulmonary dysfunction in meconium aspiration syndrome (MAS), is produced by bronchiolar obstruction and surfactant inactivation. It has been shown that substances in meconium, e.g. fatty acids, inhibit surfactant activity. However, the role of the enzyme phospholipase A 2 (PLA 2 ), which hydrolyses surfactant in adult respiratory distress syndrome (ARDS), has not yet been studied. Our objective was to investigate whether PLA 2 is present in meconium and inhibits pulmonary surfactant activity in vitro. Therefore, the presence of PLA 2 activity in meconium, collected from 10 newborns, was measured by the formation of lysophosphatidylcholine after incubation of meconium with radioactively labelled dipalmitoylphosphati‐dylcholine. Meconium was fractionated by Sephadex G‐100 column chromatography and the fractions were assayed for PLA 2 activity. Also, their effect on the surface tension of surfactant (Curosurf) was measured using a pulsating bubble surfactometer (PBS). PLA 2 activity was present in all meconium samples. Addition of meconium to surfactant significantly increased surface tension (mean ± SD: 17 ± 1.6 mN/m to 24.3 ± 6.7 mN/m, p = 0.0001) and only the addition of the PLA 2 containing fraction from meconium to surfactant also significantly increased surface tension (mean 1.7 ± 1.6mN/m to 19.0 ± 3.58 mN/m, p < 0.0001). Conclusion: PLA 2 is present in meconium and inhibits the activity of pulmonary surfactant in vitro. Therefore, PLA 2 in meconium may contribute to surfactant inactivation and alveolar ateectasis in MAS.