Neuroimmunophysiology of the gastrointestinal mucosa: implications for inflammatory diseases.

In conclusion, studies of the neuroimmunophysiology of the intestinal mucosa of the past 5-8 years have demonstrated an important role for the immune system in modulating water and electrolyte transport as well as intestinal motility in the gut. Activation of mast cells and phagocytes leads to heightened Cl- and water secretion, as well as changes in intestinal motility which leads to diarrheal states. These diarrheal responses are self-protective; they rid the intestine of offending microorganisms and antigens. Our investigation of this response has uncovered a new immune accessory cell Cz, the intestinal myofibroblast. This cell seems to play an important role in amplifying the immune signal. This cell is probably also important for the secretion of growth factors onto the epithelium and also the secretion of collagen which results in fibrosis under diseased states. These intestinal myofibroblasts are prolific prostaglandin producers, an important finding because prostaglandin synthesis inhibition has been shown to decrease the development of neoplasia in the gut. Thus, these intestinal myofibroblasts may have other important roles in addition to just modulating water and electrolyte secretion or gut motility. Our laboratory is now engaged in studying these intestinal myofibroblasts in some detail hoping to better understand the biology of these interesting cells.