Gene expression of group II phospholipase A2 in intestine in Crohn's disease

Abstract

Objective: Phospholipase A2 (PLA2) has been suggested to play an important role in the pathogenesis of inflammatory bowel diseases. Our aim was to identify cells that express group II phospholipase A2 (PLA2-II) at the mRNA and enzyme protein levels in the intestine in Crohn's disease.

Methods: Tissue samples were obtained from the intestine of 20 patients with Crohn's disease (seven operated and 13 colonoscopied) and from eight control patients without inflammatory diseases. The samples were studied by immunohistochemistry for PLA2-II enzyme protein and in situ hybridization for PLA2-II mRNA.

Results: PLA2-II protein and mRNA were detected in the Paneth cells of the small intestinal mucosa in all patients and controls. PLA2-II protein and mRNA were found in the columnar epithelial cells of the small intestinal mucosa in six of eight and eight of eight patients with Crohn's ileitis, respectively. In the eight control patients PLA2-II protein and mRNA were not found in these cells (p = 0.007 and p < 0.001, respectively). Metaplastic Paneth cells, which consistently contained PLA2-II mRNA, were found in the colonic mucosa in five of six patients with Crohn's colitis and of one of eight control patients (p = 0.026). The columnar epithelial cells of the colonic mucosa contained PLA2-II protein in three of six and PLA2-II mRNA in six of six patients with Crohn's colitis, whereas the protein was found in these cells in none of eight of the controls (p = 0.055) and the mRNA in only one of eight (p = 0.005) controls.

Conclusions: In Crohn's disease, Paneth cells and columnar epithelial cells of the small and large intestinal mucosa synthesize PLA2-II at the site of active inflammation.