Cell sheets for ectocornea formation, method of producing the same and method of using the same

Abstract

The present invention has as its objective providing acorneal epithelium forming cell sheet that will adhere well to an anterior segment tissue. To attain this objective, a corneal epithelium forming cell sheet is produced by a process comprising the steps of cultivating under specified conditions corneal epithelium forming cells on a cell culture support comprising a substrate having its surface covered with a temperature responsive polymer of which the hydrating force varies in a temperature range of 0-80° C., optionally stratifying the layer of cultured cells, and thereafter, (1) adjusting the temperature of the culture solution to either above an upper critical dissolution temperature or below a lower critical dissolution temperature, (2) bringing the cultured corneal epithelium forming cells into close contact with a carrier, and (3) detaching the sheet together with the carrier under specified conditions.

Description

TECHNICAL FIELD OF THE INVENTION [0001] This invention relates to corneal epithelium forming cell sheets in biology, medicine and other fields, as well as processes for producing such sheets, and therapeutic methods using them. BACKGROUND ART [0002] With marked advances in medical technology, it has recently become popular to perform organ transplants, i.e., replacing a difficult-to-treat organ with another person's organ. The organs that can be transplanted are quite diverse and include the skin, cornea, kidney, liver and heart, and in addition, the postoperative progress of organ transplants has improved so remarkably that they are already becoming established as a medical procedure. Keratoplasty is one example and as early as 40 years ago, an eye bank was organized in Japan to start transplanting activities. However, as of today, the number of donors in Japan is very small and notwithstanding the fact that there are annually about 20,000 patients who need keratoplasty, only a ten...

AI Technical Summary

Benefits of technology

[0018] In order to attain the stated objects, the present inventors engaged in R&D activities taking various angles of study. As a result, the inventors found that a corneal epithelium forming cell sheet that would adhere very well to a living tissue could be obtained by a process comprising the steps of cultivating corneal epithelium forming cells under specified conditions on a cell culture support comprising a substrate having its surface covered with a specified temperatu

Problems solved by technology

However, as of today, the number of donors in Japan is very small and notwithstanding the fact that there are annually about 20,000 patients who need keratoplasty, only a tenth of them (ca.

Although keratoplasty is a virtually established procedure, it suffers the problem of shortage in donors, giving rise to the need for the development of a next-generation medical procedure.

However, the artificial skin using synthetic polymers has the potential to cause rejection and other side effects that make it undesirable as skin grafts.

However, it has been pointed out that the recovery of grown cells by treatment with chemical reagents involves some disadvantages such as the processing steps becoming cumbersome to increase the chance of contamination by impurities and the grown cells becoming denatured or damaged by the chemical treatment to have their inherent functions injured.

(5) As the result, the diseased site to which the cell sheet has been grafted is prone to infection.

In addition to these defects of the prior art method, anterior segment related cells that are contemplated in the present invention, such as corneal epithelial cells, corneal endothelial cells and conjunctival epithelial cells, do not have as strong intercellular binding as dermal cells and have had the problem that cultivated cells cannot be detached and recovered as a single sheet even if the dispase is employed.

However, the cultured corneal epithelial sheet described in WO 98 / 31316 has been detached by the dispase treatment and has had the problem that it adheres so poorly to the laser ablated corneal tissue that no significant therapeutic efficacy is achievable.

However, the cultured oral mucosa reported in the article was detached by dispase treatment and had the problem that it adhered so poorly to the corneal tissue of the patient that no significant therapeutic efficacy would be achievable.