[Mucosal protection by phosphatidylcholine as new therapeutic concept in ulcerative colitis]

The colonic mucus serves a first barrier towards invasion of commensal bacteria in stool. One essential component of intestinal mucus is phosphatidylcholine (PC) which represents more than 90 % of the phospholipids in mucus indicative for a selective transport of PC into this compartment. It is arranged in lamellar structures as surfactant-like particles which provide a hydrophobic surface on top of the hydrated mucus gel to prevent invasion of bacteria from the intestinal lumen. In ulcerative colitis (UC) the mucus PC content is reduced by 70 % irrespective of the state of inflammation. Thus, it could represent an intrinsic primary pathogenetic condition predisposing to bacterial invasion and precipitation of inflammation. Since PC was shown to be mainly secreted by the ileal mucosa from where it is assumed to move distally to the colon, the PC content along the colonic wall towards the rectum gradually thins out with lowest PC content in the rectum. It explains the start of the clinical manifestation of UC in the rectum and expansion from there to the upper parts of the colon. When the lacking mucus PC in the UC was supplemented by an oral, delayed released PC preparation, it was shown in three clinical trials that the inflammation improved and even resolved. The data indicate the essential role of the mucus phosphatidylcholine content for protection against inflammation in colon. This can be the basis for the development of an innovative therapy for ulcerative colitis using orally available delayed released phosphatidylcholine.