Introduction: Secretory phospholipase A2 is supposed to play a role in
acute lung injury but no data are available for pediatric acute
respiratory distress syndrome (ARDS). It is not clear which enzyme
subtypes are secreted and what the relationships are between enzyme
activity, biophysical and biochemical parameters, and clinical outcomes.
We aimed to measure the enzyme and identify its subtypes and to study
its biochemical and biophysical effect. The secondary aim was to
correlate enzyme activity with clinical outcome.
Methods: Bronchoalveolar lavage was performed in 24 infants with ARDS
and 14 controls with no lung disease. Samples were assayed for secretory
phospholipase A2 and molecules related to its activity and expression.
Western blotting and captive bubble surfactometry were also performed.
Clinical data were real time downloaded.
Results: Tumor necrosis factor-alpha (814 (506-2,499) vs. 287
(111-1,315) pg/mL; P = 0.04), enzyme activity (430 (253600) vs. 149
(61-387) IU/mL; P = 0.01), free fatty acids (4.3 (2.8-8.6) vs. 2
(0.8-4.6) mM; P = 0.026), and minimum surface tension (25.6 +/- 6.1 vs.
18 +/- 1.8 mN/m; P = 0.006) were higher in ARDS than in controls.
Phospholipids are lower in ARDS than in controls (76.5 (54-100) vs.
1,094 (536-2,907) mu g/mL; P = 0.0001). Three enzyme subtypes were
identified (-IIA, -V, -X), although in lower quantities in controls;
another subtype (-IB) was mainly detected in ARDS. Significant
correlations exist between enzyme activity, free fatty acids (rho =
0.823; P < 0.001), and surface tension (rho = 0.55; P < 0.028).
Correlations also exist with intensive care stay (rho = 0.54; P =
0.001), PRISM-III24 (rho = 0.79; P < 0.001), duration of ventilation
(rho = 0.53; P = 0.002), and oxygen therapy (rho = 0.54; P = 0.001).
Conclusions: Secretory phospholipase A2 activity is raised in pediatric
ARDS and constituted of four subtypes. Enzyme correlates with some
inflammatory mediators, surface tension, and major clinical outcomes.
Secretory phospholipase A2 may be a clinically relevant target in
- BRONCHOALVEOLAR LAVAGE
- LUNG INJURY