GENE-EXPRESSION OF GROUP-II PHOSPHOLIPASE-A2 IN INTESTINE IN ULCERATIVE-COLITIS

Background-It has been suggested that phospholipase A2 (PLA2) has an e ssential role in the pathogenesis of inflammatory bowel diseases. Aims -This study aimed at identifying cells in intestinal and mesenteric ti ssue samples that might express group II phospholipase A2 (PLA2-II) at the mRNA and enzyme protein levels in patients with ulcerative coliti s. Patients and tissue samples-Tissue samples were obtained from the i ntestine, mesentery, skeletal muscle, and subcutaneous fat of six pati ents who underwent panproctocolectomy for severe ulcerative colitis. M ucosal biopsy specimens were obtained from the colon of another group of six patients with ulcerative colitis during routine diagnostic colo noscopies. Tissues from six patients without intestinal inflammatory d iseases served as controls. Methods-Tissue samples were studied by lig ht microscopy, immunohistochemistry for PLA2-II enzyme protein, and in situ hybridisation and northern hybridisation for PLA2-II mRNA. Resul ts-PLA2-II mRNA and PLA2-II protein were detected in metaplastic Panet h cells in six patients and in the columnar epithelial cells of coloni c mucosa in four out of six patients with active ulcerative colitis. P ositive findings were less numerous in patients with mild ulcerative c olitis. Only two out of six control patients had a weak positive signa l for PLA2-II mRNA and one of these two patients had a weak positive i mmunoreaction for PLA2-II in columnar epithelial cells in the colonic mucosa. None of the control patients had metaplastic Paneth cells. Con clusions-Metaplastic Paneth cells and colonic epithelial cells synthes ise PLA2-II in ulcerative colitis. The activity of the PLA2-II synthes is seems to be related to the degree of inflammation in the diseased b owel.