The main cell types and cell differentiation mechanisms involved in ECM secretion and fibrosis in intestine. EMT, epithelial-mesenchymal transition; EndoMT, endothelial-to-mesenchymal transition; TLR, Toll-like receptor; NLR, Nod-like receptor; IL, interleukin; TNF, tumor necrosis factor; TGF-β1, transforming growth factor beta 1.