Roles of secretory phospholipases A(2) in inflammatory diseases and trauma

Six distinct secretory small molecular weight phospholipases A(2) (PLA(2)) have been cloned and characterized from human tissues. Two of them, pancrea tic group TB PLA(2) (PLA(2)-IB) and synovial-type group IIA PLA(2) (PLA(2)- IIA) have been studied as to their association to various inflammatory dise ases. PLA(2)-IB is a digestive enzyme synthesized by pancreatic acinar cell s. In acute pancreatitis, which is characterized by destruction of pancreat ic tissue, PLA(2)-IB is released into the circulation, but its role in panc reatic and other tissue damage is still hypothetical. The concentration of PLA(2)-IIA increases in blood plasma in generalized inflammatory response r esulting from infections, chronic inflammatory diseases, acute pancreatitis , trauma and surgical operations. PLA(2)-IIA is synthesized in a number of gland cells and is present in cellular secretions on mucosal surfaces inclu ding Paneth cells of intestinal mucosa, prostatic gland cells and seminal p lasma, and lacrimal glands and tears. PLA(2)-IIA is expressed in hepatoma-d erived cells in vitro and hepatocytes in vivo. PLA(2)-IIA is regarded as an acute phase protein and seems to function as an antibacterial agent especi ally effective against Gram-positive bacteria. Other putative functions in the inflammatory reaction include hydrolysis of cell membrane phospholipids and release of arachidonic acid for prostanoid synthesis. (C) 2000 Elsevie r Science B.V. All rights reserved.