Role of myofibroblasts in inflammatory bowel disease and tumourigenesis

Myofibroblasts are specialized mesenchymal cells that exhibit the ultrastructural features of both fibroblasts and smooth muscle cells. They contain -smooth muscle actin (-SMA) and vimentin, but not desmin. These cells are located in the lamina propria under the epithelial cells in the intestine. Myofibroblasts, like intestinal epithelial cells, proliferate, differentiate and migrate towards the intestine lumen and finally undergo apoptosis. These cells secrete cytokines, chemokines, growth factors, prostaglandins and components of the extracellular matrix. The inflammation increases their number. Subepithelial myofibroblasts constitutively express molecules of class II major histocompatibility complex; therefore they may function as non-professional antigen-presenting cells. It is considered that myofibroblasts may play an important role in organogenesis, epithelial cell growth and differentiation, inflammation, healing of mucosa injuries, tissue regeneration as well as in fibrosis and carcinogenesis. Explanation of their properties may help in understanding of the aetiology of such diseases as inflammatory bowel disease (IBD).