Expression of transforming growth factor β superfamily and their receptors in the corneal stromal wound healing process after excimer laser keratectomy

Editor,—Corneal stromal clouding (corneal haze) develops after excimer laser keratectomy. During the corneal wound healing process after excimer laser keratectomy, abnormal subepithelial fibrous tissue is formed just under the abraded area, where keratocytes proliferate and extracellular matrix (ECM) components, including collagens (type III, IV, and VII), fibronectin, laminin, and tenascin, are deposited.1-3 This abnormal ECM deposition is thought to correspond to the corneal haze. The transforming growth factor β (TGF-β) superfamily contains many multifunctional proteins, including TGF-βs, activins, and bone morphogenetic proteins (BMPs).4 They regulate cellular proliferation, differentiation, migration, and ECM production.4 Through these functions, TGF-β is known to regulate the wound healing process in many tissue. For example, TGF-β accelerates the abnormal …