RESUMO
Context: Sub-epithelial myofibroblasts are known to influence the biology (proliferation, differentiation and apoptosis) of overlying epithelia. In the intestine, myofibroblasts have been demonstrated to be essential for epithelial differentiation. It is therefore hypothesized that myofibroblasts may also be involved in intestinal metaplasia that is characteristic of Barrett esophagus. Objective: This study endeavors to immunohistologically evaluate epithelial-myofibroblast interaction in Barrett's metaplasia. Materials and Methods: Nineteen archival esophageal endoscopic biopsies of Barrett's metaplasia were immune-phenotyped for the following epithelial and myofibroblast antigens - cytokeratins (CK) 8, 13, 18, CDX2 (Caudal type homeobox 2), a-smooth muscle actin (SMA). Results: α-SMA immunostaining revealed close association between myofibroblasts and metaplastic Barrett's epithelium but not with normal esophageal squamous epithelium. Myofibroblasts were more prominent in dysplastic than in non-dysplastic Barrett metaplasia. CDX2 and CK 8/18, indicators of intestinal differentiation were expressed in Barrett metaplasia but not normal esophageal squamous epithelium, while the reverse was the case for CK 13, which only stained normal esophageal squamous epithelium. Conclusion: Although their precise role is yet to be clearly defined, sub-epithelial myofibroblasts are very likely involved in the pathogenesis of Barrett's metaplasia.