Intestinal mucosal mast cells.

ABSTRACT

Mast cells are unique tissue cells with high affinity surface receptors for IgE and the capacity to synthesize and store histamine in mediator-containing cytoplasmic granules that stain metachromatically upon exposure to cationic dyes. The prominence of mast cells in the gastrointestinal tract and the potential effects of newly generated and preformed mediators released by stimulated mast cells on surrounding gastrointestinal tissues have raised important questions regarding the role of the mast cell in both physiologic and pathophysiologic events in the gut. The elucidation of the role of the mast cell in the gastrointestinal tract is a complex task as illustrated by studies revealing the presence of heterogeneous populations of mast cells in this organ. Morphologic, biochemical, and functional differences have been demonstrated between mast cells located primarily in the mucosa (atypical or mucosal mast cells) and mast cells distributed throughout the connective tissues of the gut (typical or connective tissue mast cells). Awareness of the distinguishing features of mast cell populations in the gut is an important step in unraveling the functional role of gastrointestinal mast cells and may lead to the development of innovative therapeutic approaches to gastrointestinal diseases in which mast cell activation occurs.