Immunohistochemical study of myofibroblasts in normal colonic mucosa, @entity1127 , and adenomatous XXXX .

@entity652 @entity32 @entity1 @entity2283 @entity1127 @entity5 @entity1412 @entity2918 @entity2277 @entity6523 @entity2467 @entity2513
CONTEXT: Myofibroblasts are distinct cells with characteristics of both smooth muscle cells and fibroblasts. Through their ability to secrete cytokines, chemokines, @entity2918 , growth factors, and matrix components, they are thought to play critical roles in @entity32 , growth, repair, and @entity5 . OBJECTIVE: The goal of this study was to identify the distinct cell populations of the lamina propria of normal colon and @entity1127 . DESIGN: We studied the expression of alpha-smooth muscle actin (alphaSMA), smooth muscle myosin (SMM), @entity2283 , @entity2277 , and @entity2467 by intestinal mesenchymal (stromal) cells in the normal colonic mucosa (n = 5), as well as in @entity1127 (n = 5), sporadic @entity2513 (n = 47), and @entity652 from @entity1 with @entity1412 (n = 36). RESULTS: In the normal colonic mucosa, the pericryptal stromal cells were alphaSMA+, SMM+, @entity2283 -, and @entity2277 +, defining them as myofibroblasts. In contrast, cells of the muscularis mucosae were alphaSMA+, SMM+, @entity2283 +, and @entity2277 -, defining them as smooth muscle cells. alpha-Smooth muscle actin also highlighted direct connections between the muscularis mucosae and the pericryptal myofibroblasts, and @entity2277 immunostaining showed a network of connections between the alphaSMA+ pericryptal myofibroblasts and the alphaSMA- fibroblasts in the interstitium. In all @entity1127 and @entity6523 , the interstitial stromal cells (fibroblasts) now also express alphaSMA and form a syncytium of alphaSMA+ networklike connections throughout the lamina propria. Stromal cells of sporadic @entity652 demonstrated the same immunohistochemical staining characteristics displayed by @entity652 from @entity1 with @entity1412 and by @entity1127 . Conclusions.-These findings indicate that in normal colon, alphaSMA- fibroblasts are the predominant cell type in the lamina propria. However, the pericryptal (subepithelial) stromal cells are a distinct cell type (alphaSMA+ myofibroblast) that is immunophenotypically different from muscularis mucosae smooth muscle cells and are connected to the interstitial, nonpericryptal fibroblasts with which they exist as a network throughout the lamina propria of the normal colon. Furthermore, in both hyperplastic and @entity1127 , there are changes in nonpericryptal fibroblasts from @entity2277 +, alphaSMA-, and SMM- to @entity2277 +, alphaSMA+, and SMM+; thus, the interstitial fibroblasts are replaced by myofibroblasts. The factors that cause these changes and the origin of the myofibroblasts need to be determined to clarify the biology of colorectal tumorigenesis.
