Bronchoalveolar lavage fluid phospholipase a2 activities are increased in human adult respiratory distress syndrome. Kim, Dae Kyong, Taeko Fukuda, B. Taylor Thompson, Barbara Cockrill, Charles Hales, and Joseph V. Bonventre. Medical Services, Massachusetts General Hospital and Department of Medicine, Harvard Medical School, Boston MA 02115
APStracts 2:0036L, 1995.
The role of phospholipase A2 (PLA2) in lung injury in humans is unclear. Previous studies have failed to identify an increase in PLA2 activity in bronchoalveolar lavage fluids (BALF) of patients with the adult respiratory distress syndrome (ARDS). In this study increased PLA2 activity was detected in BALF from patients with ARDS. PLA2 levels in BALF correlated positively with lung injury score in patients with lung disease. BALF PLA2 activity in patients with ARDS was resolved into heparin binding and non-binding actvities. Both PLA2 activities were increased in BALF of ARDS patients. The PLA2 activity that bound to heparin was identified as a Group II PLA2 by its chromatographic characteristics, its inhibition by dithiothreitol, its substrate specificity and its approximate molecular mass of 14 kDa. The second PLA2 activity was further purified and found to require Ca2+ at a concentration greater than 2 x 10-4 M for activity. This form of PLA2 exhibited a neutral and broad pH optimum (pH 6.0-pH 8.0) and hydrolyzed both phosphatidylethanolamine and phosphatidylcholine effectively. Its apparent molecular mass was estimated to be 80-90 kDa. Neither anti -pancreatic PLA2 antiserum nor anti-pig spleen cytosolic 100 kDa PLA2 antiserum immunoprecipitated the enzymatic activity. Thus at least two forms of PLA2 are increased in activity in BALF of patients with ARDS, a Group II PLA2 and a biochemically and immunochemically form distinct from Group I, Group II and cytosolic PLA2. Increased lung PLA2 activity may be important for the pathophysiology of ARDS. 

Received 8 September 1994; accepted in final form 1 March 1995.
APS Manuscript Number L266-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 21 March 1995.