Secretory phospholipase A(2) in newborn infants with sepsis.

OBJECTIVE: To investigate secretory phospholipase A(2) (sPLA(2)) activity in neonatal sepsis. STUDY DESIGN: Plasma sPLA(2) activity, C-reactive protein (CRP) concentration, leukocyte count and immature/total neutrophil (I/T) ratio were assessed in a group of 156 infants admitted for neonatal intensive care, who were classified as documented sepsis (n=24), suspected infection (n=77) and controls (n=55). Interleukin-6 (IL-6) concentrations were assessed in a subgroup (n=29). RESULT: sPLA(2) activity, CRP concentration and I/T ratio were higher in sepsis than in suspected infection or control groups. sPLA(2) activity advanced with increasing CRP, I/T ratio and IL-6 was highest in infants with respiratory distress syndrome (RDS). Compared to CRP, sPLA(2) had equal sensitivity and lower specificity. Compared to I/T ratio, sensitivity and specificity of sPLA(2) were higher. CONCLUSION: Plasma sPLA(2) activity is increased in neonatal sepsis and highest in infants with RDS. Further studies should assess the potential of sPLA(2) inhibition in neonatal sepsis.

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

UNLABELLED: 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 A2 (PLA2), which hydrolyses surfactant in adult respiratory distress syndrome (ARDS), has not yet been studied. Our objective was to investigate whether PLA2 is present in meconium and inhibits pulmonary surfactant activity in vitro. Therefore, the presence of PLA2 activity in meconium, collected from 10 newborns, was measured by the formation of lysophosphatidylcholine after incubation of meconium with radioactively labelled dipalmitoylphosphatidylcholine. Meconium was fractionated by Sephadex G-100 column chromatography and the fractions were assayed for PLA2 activity. Also, their effect on the surface tension of surfactant (Curosurf) was measured using a pulsating bubble surfactometer (PBS). PLA2 activity was present in all meconium samples. Addition of meconium to surfactant significantly increased surface tension (mean +/- SD: 1.7 +/- 1.6 mN/m to 24.3 +/- 6.7 mN/m, p = 0.0001) and only the addition of the PLA2 containing fraction from meconium to surfactant also significantly increased surface tension (mean 1.7 +/- 1.6 mN/m to 19.0 +/- 3.58 mN/m, p < 0.0001). CONCLUSION: PLA2 is present in meconium and inhibits the activity of pulmonary surfactant in vitro. Therefore, PLA2 in meconium may contribute to surfactant inactivation and alveolar atelectasis in MAS.