The exact origin of inflammatory bowel disease (IBD) is still unknown. The current hypothesis is that IBD is secondary to an abnormal intestinal immun response directed to all or part of the intestinal flora in genetically predisposed individuals. Several experimental studies have demonstrated the ability of mesenchymal stem cells (MSCs) from bone marrow or adipose tissue origin to control intestinal inflammation in animal models. However, to date, there are no data regarding the functions of resident MSCs in the colon and small intestine of IBD patients. We hypothesize that dysfunction of resident intestinal MSCs contributes to the disruption of intestinal homeostasis in patients with IBD causing the development of intestinal inflammation. The aim of this research project is to identify, describe and characterize at the molecular and functional level MSCs of the colon and small intestine of patients with Crohn's disease and ulcerative colitis and to compare them with a control population.