Chinese researchers are cultivating human cells to make artificial corneas, bringing hope to the nation's 5 million victims of corneal blindness.

The research team from the Ocean University of China is expected to produce a complete cornea and begin clinical trials in three to five years, said Fan Tingjun, deputy dean of the university's College of Marine Life Science.

An artificial cornea, expected to cost 10,000 to 20,000 yuan (US$1,475 to US$2,950) each, would provide an alternative for patients awaiting donated corneas for transplant surgery, Fan said.

"Chinese doctors can only perform corneal transplant operations, currently the only cure for corneal blindness, on 3,000 to 4,000 people every year due to a lack of donors," he said.

The cornea, a vulnerable shield protecting the eye and which plays a key role in creating vision, consists of three main layers -- the endothelium, stroma and epithelium.

The team had made a major breakthrough by using tissue-engineering technologies to create a tissue similar to the endothelium, an innermost, single layer of cells essential to keeping the cornea clear, Fan said.

The creation of endothelium remained a key barrier in the global study of artificial corneas because the cells of the endothelium could not regenerate, said Fan, whose team started their research in 2002.

After nine years of trial and error, the team successfully cultivated a large quantity of endothelial cells.

The researchers transplanted the artificial endothelium into a rabbit, which maintained the transparency of its cornea for more than a year.

Now the team is working on the production of stroma, which accounts for 90 percent of the thickness of the cornea and serves as a bridge between the endothelium and epithelium, the outmost layer of the cornea to block dust and bacteria from reaching the eye, as well as absorb oxygen and nutrients from tears.

Although foreign researchers have produced artificial stroma similar to that found in the human eye, these have not functioned well when transplanted in animals, Fan said.

"We have chosen proper seed cells and supports made of composite materials to produce stroma. Now, we're performing adjustments of the supports' structure and function and hopefully will be finished in three to five years," Fan said.

The researchers are working with the Qingdao Yuming Biotechnologies Co Ltd to produce 150,000 to 200,000 pieces of endothelium every year to benefit more than 800,000 Chinese whose endothelium was damaged.

"Mass production of complete corneas will be launched after the artificial cornea passes clinical trials," Fan said.

(Xinhua News Aency July 26, 2010)