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Phospholipase A2 is present in meconium and inhibits the activity of pulmonary surfactant: an in vitro study

A J Schrama1, A J de Beaufort, Y R Sukul

  • 1Department of Pediatrics, Leiden University Medical Center, The Netherlands. A.J.J.Schrama@kgc.azl.nl

Acta Paediatrica (Oslo, Norway : 1992)
|May 3, 2001
PubMed
Abstract

Insights

Phospholipase A2 (PLA2) is found in meconium and inactivates pulmonary surfactant, potentially causing atelectasis in newborns with meconium aspiration syndrome (MAS). This study confirms PLA2

Area of Science:

  • Neonatal respiratory medicine
  • Biochemistry
  • Pulmonary physiology

Background:

  • Atelectasis is a primary cause of respiratory issues in meconium aspiration syndrome (MAS).
  • Meconium components, such as fatty acids, are known to inhibit pulmonary surfactant function.
  • The role of phospholipase A2 (PLA2), an enzyme implicated in surfactant hydrolysis in adult respiratory distress syndrome (ARDS), remained uninvestigated in MAS.

Purpose of the Study:

  • To determine the presence and activity of PLA2 in meconium.
  • To evaluate the inhibitory effect of meconium-derived PLA2 on pulmonary surfactant activity in vitro.

Main Methods:

  • Meconium samples from 10 newborns were analyzed for PLA2 activity by measuring lysophosphatidylcholine formation from labeled dipalmitoylphosphatidylcholine.
  • Meconium was fractionated using Sephadex G-100 column chromatography.
  • The effect of meconium and its fractions on Curosurf (pulmonary surfactant) activity was assessed using a pulsating bubble surfactometer (PBS) by measuring surface tension.

Main Results:

  • PLA2 activity was detected in all tested meconium samples.
  • The addition of meconium significantly increased the surface tension of pulmonary surfactant (from 1.7 +/- 1.6 mN/m to 24.3 +/- 6.7 mN/m, p = 0.0001).
  • A PLA2-containing fraction isolated from meconium also significantly increased surfactant surface tension (from 1.7 +/- 1.6 mN/m to 19.0 +/- 3.58 mN/m, p < 0.0001).

Conclusions:

  • Phospholipase A2 (PLA2) is present in meconium.
  • Meconium-derived PLA2 inhibits pulmonary surfactant activity in vitro.
  • PLA2 in meconium may be a contributing factor to surfactant inactivation and subsequent alveolar atelectasis in MAS.

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