Can we produce a human corneal equivalent by tissue engineering?

Tissue engineering is progressing rapidly. Bioengineered substitutes are al ready available for experimental applications and some clinical purposes su ch as skin replacement. This review focuses on the development of reconstru cted human cornea in vitro by tissue engineering. Key elements to consider in the corneal reconstruction, such as the source for epithelial cells and keratocytes. are discussed and the various steps of production are presente d. Since one application of this human model is ro obtain a better understa nding of corneal wound healing, the mechanisms of this phenomenon as well a s the function played both by membrane-bound integrins and components from the extracellular matrix have also been addressed. The analysis of integrin s by immunohistofluorescence labelling of our reconstructed human cornea re vealed that beta(1), alpha(3), alpha(5), and alpha(6) integrin subunits wer e expressed but alpha(4) was not. Laminin. type VII collagen and fibronecti n were also detected. Finally, the future challenges of corneal reconstruct ion by tissue engineering are discussed and the tremendous applications of such tissue produced in vitro for experimental as well as clinical purposes are considered, (C) 2000 Elsevier Science Ltd. All rights reserved.