Increase of Colonic Mast Cells in Obstructed Defecation and Their Relationship with Enteric Glia

Mast cells are involved in visceral hypersensitivity and motor activity of the gastrointestinal tract. However, there is almost no information concerning mast cells in constipated patients. The purpose of this study was to investigate mast cells distribution in all colonic layers in controls and severely constipated patients with obstructed defecation. Full-thickness specimens from colons of patients undergoing surgery for obstructed defecation due to refractoriness to other therapeutic interventions (n = 11), compared to controls, were obtained and the number of mast cells (evaluated by specific monoclonal antibodies) were counted in the whole viscus and in the various colonic segments (cecum, ascending, transverse, descending, and sigmoid). Compared to controls, constipated patients had significantly higher numbers of mast cells, both as an overall number and in single colonic segments. This increase was especially evident in the mucosa and submucosa. Mast cells were homogeneously represented in the various segment of the large bowel, in both controls and patients. Degranulated mast cells were found to be close to enteric glial cells and glial filaments. Colonic mast cells are increased in obstructed defecation patients. This might represent a vicariating mechanism to the impaired colonic propulsive activity of these patients.