Anomalies cellulaires de l'épithélium au cours des maladies inflammatoires

Abstract

The intestinal epithelium plays critical roles in maintenance of the body's homeostasis due to its many functions such as providing a barrier to the outside world, handling of water and electrolytes, and contributing to mucosal immunological processes. Since many of these functions are perturbed in patients with inflammatory bowel diseases, leading to increased permeation of the barrier by luminal antigens and pro-inflammatory molecules, the generation of diarrhoea and an apparent disturbance of immunological accessory function, important pathogenic roles of the epithelium in inflammatory bowel diseases are likely. Although many putative mechanisms of mucosal and luminal origin which may underly these changes have been identified, the differentiation of epithelial abnormalities that are a consequence of inflammation from those that occur earlier in pathogenesis is problematical. Nevertheless, the identification of epithelial abnormalities occurring specifically in ulcerative colitis and independently of the presence of mucosal inflammation has suggested a pivotal role of the large bowel epithelium in early events during the pathogenesis of ulcerative colitis. Evidence that a primary abnormality of intestinal epithelium underlies Crohn's disease, however, remains scant. Increased knowledge of the pathobiology of the intestinal epithelium in inflammatory bowel diseases may lead not only to a greater understanding of disease pathogenesis but also to the development of novel therapeutic approaches.