Distribution of the matrix metalloproteinases stromelysin, gelatinases A and B, and collagenase in Crohn's disease and normal intestine.

AIMS To investigate the role of the matrix metalloproteinases (MMPs) in the connective tissue changes seen in the intestine in Crohn's disease. METHODS Indirect immunofluorescence microscopy using specific antibodies to the MMPs (collagenase, gelatinase A and B, and stromelysin) were used to assess the distribution of these enzymes in normal and diseased intestine. RESULTS In normal intestine the matrix metalloproteinases were confined to a few isolated inflammatory cells, but in Crohn's disease, the inflammatory infiltrate was associated with increased numbers of polymorphonuclear leucocytes which stained positive for gelatinase B. Stromelysin was also detected extracellularly on the connective tissue matrix in regions of smooth muscle cell proliferation and mucosal degradation. Interestingly, in ulcerative colitis, another inflammatory bowel disease, stromelysin was localised in the lamina propria in regions of mucosal loss. CONCLUSIONS The increased numbers of inflammatory cells containing gelatinase B, and the localisation of extracellular stromelysin in regions of fibrosis and mucosal degradation, suggest that these enzymes have a role in the pathological changes seen in Crohn's disease. In cases of ulcerative colitis stromelysin was also detected on the lamina propria in regions of mucosal loss, and seems to be associated with the connective tissue changes that precede mucosal loss.