INTRALUMINAL EXCRETION OF PAF, LYSOPAF, AND ACETYLHYDROLASE IN PATIENTS WITH ULCERATIVE-COLITIS

PAF-acether (PAF) is a phospholipid synthesized by numerous inflammato ry cells. PAF can produce several pathological changes in various orga ns, especially in the colon, In animals PAF causes colonic ulceration and inflammation, which are similar to the anatomic lesions seen in hu man ulcerative colitis. The aim of this study was to measure in vivo c olonic production of PAF in active ulcerative colitis using a modified colonic perfusion method, Ten patients with active ulcerative colitis and six control patients were investigated, A colonic segment was con tinuously perfused with a buffer and the liquid was recovered 20 cm di stally, after a 45-min period of equilibration, at 20-min intervals. P AF, lysoPAF, and acetylhydrolase were measured in the colonic samples, PAF and lysoPAF outputs were significantly higher in patients with ac tive ulcerative colitis compared to controls patients. There was a sig nificant correlation between colonic PAF output and, respectively, mac roscopic mucosal lesions and myeloperoxidase colonic output. We thus c onclude: (1) the colonic perfusion method allows in vivo study of the metabolism of PAF during ulcerative colitis and could also be used to study the efficiency of PAF antagonists in UC; and (2) colonic product ion of PAF is increased during ulcerative colitis and correlated to lo cal injury and inflammation, Whether or not PAF plays a role in the pa thogenesis of ulcerative colitis remains open for further investigatio ns.