10 Current and Novel Treatments for Ulcerative Colitis Cuong D. Tran, Rosa Katsikeros and Suzanne M. Abimosleh Gastroenterology Unit, Women’s and Children’s Health Network, North Adelaide Discipline of Physiology, School of Medical Sciences, University of Adelaide Australia 1. Introduction Ulcerative colitis and Crohn’s disease are defined by a common term of inflammatory bowel disease. These chronic diseases result in significant morbidity and mortality. While there are no cures for these diseases, the last two decades have been a period of major advancement in our understanding of the biology of intestinal inflammation. This can be attributed to a steadily increasing number of experimental animal models with some clinical manifestation similar to those observed in human inflammatory bowel disease. These experimental animal models have also contributed greatly to our current understanding of the immunological, pathological and physiological features of chronic intestinal inflammation. However, specific causes of ulcerative colitis and Crohn’s disease remain unknown. Conventional treatments for the disease include corticosteroids and immunosuppressives, however treatments in many patients are not entirely effective with many therapies associated with significant adverse effects. Thus, treatments that are effective and have little or no side effects remain an unmet need. There are numerous emerging therapeutic strategies which may be useful in the alleviation of chronic intestinal inflammation and this chapter will focus on novel therapies that may be effective for ulcerative colitis in the future. 2. Etiology of ulcerative colitis While the precise etiology of inflammatory bowel disease is unknown, genetic susceptibility, environmental factors, impaired barrier function, imbalances or disruption to the commensal host microflora and an abnormal intestinal immune response are thought to play an important role in its manifestation. 2.1 The immune response It is clear that not one single component of inflammatory bowel disease pathogenesis can trigger and maintain the disease. Understanding mucosal immunity in Crohn’s disease and ulcerative colitis is fundamental in unraveling the complex mechanisms of chronic gut inflammation which can then provide some insight into the treatment of inflammatory bowel disease. The immune response is divided into two components, innate immunity and adaptive immunity.