PHOSPHOLIPASE A(2) GENE-EXPRESSION AND ACTIVITY IN HISTOLOGICALLY NORMAL ILEAL MUCOSA AND IN CROHNS ILEITIS

Increased activity of phospholipase A(2) (PLA(?)2) in the heal mucosa may contribute to the inflammation in Crohn's disease. The results of this study showed that (a) three months after ileocolonic resection fo r Crohn's disease the neoterminal ileal mucosa showed endoscopically n ew inflammation and had higher PLA(2) activity than at the time of the operation (n = 8); no such findings were seen in controls (n = 7), (b ) histologically normal ileal mucosa (n = 3) contained mRNA for three isoforms of PLA(2) (PLA(2)-I, PLA(2)-II, and cPLA(2)), but the amounts of PLA(2)-II mRNA clearly exceeded the amounts of mRNA for PLA(2)-I a nd cPLA(2), (c) ileal mucosa from Crohn's patients (n = 2) contained h igher values of PLA(2)-II mRNA than ileal mucosa from two controls, (d ) ileal mucosa from Crohn's patients (n = 4) showed increased PLA(2)-I I mRNA three months after ileocolonic resection. In conclusion, these results show that the predominating PLA(2) mRNA in the human ileal muc osa is type II PLA(2), and that increased synthesis of PLA(2)-II might be responsible for the increased PLA(2) activity found in the heal mu cosa accompanying recurrent heal inflammation in Crohn's disease.