Instability of epithelial-mesenchymal cells transdifferentiation (EMT) in the formation of pseudoepitheliomatous hyperplasia / 解放军医学杂志

ABSTRACT

Objective To explore the correlation of the formation of pseudoepitheliomatous hyperplasia (PEH) after healing of inappropriately treated wound of skin with epithelial mesenchymal cells transdifferentiation (EMT). Methods Morphological change in epithelial tissue was observed with histopathologic methods in epithelial cells from PEH lesions ( n =11) and normal skin specimens obtained adjacent to PEH (PEH N, n =6) from 11 patients with PEH. At the same time, the characteristic of expressions and distribution of type Ⅰ and Ⅲ collagen, alpha smooth muscule actin (? SMA), vimentin (Vim), desmin (Des), transforming growth factor ?1 (TGF ?1)and its receptor (TGFRI), pan cytokeratin (CKp), and type Ⅳ collagen in PEH were examined with indirect immunofluorescent double labelling method. Results In comparison with PEH N, squamous epithelium in PEH presented a picture of atypical hyperplasia, there was a derangement of basal apical polarity, disrupture in structure, and a displacement of cells foward mesenchyme. Examination under electron microscope revealed deformation of epithelial basal cells, with loose intercellular junction, and newly formed tumor like cells distingaishable from original epithelial cells. Expressions of type Ⅰ and Ⅲ collagen,? SMA,Vim and Des could be detected in the epithelial cells of PEH. However,the protein expressions of CKp, Ⅳ type collagen were significantly decreased in basal epithelial cells. Furthermore, free epithelial cells expressing CKp were found in the deep layer of mesenchyme. Conclusion It was confirmed for the first time that there was a phenomenon of EMT during the course of PEH formation. Epithelial cells in PEH lesion with granuloma and non hypertrophic scar are characteristized by de differentiation, redifferentiation and a decrement of TGF ?1 induction, which are involved in reactive hyperplasia of the epithelium.