Chinese scientists to produce artificial cornea
A group of Chinese researchers are cultivating human cells to make artificial corneas in a laboratory, bringing hope to some 5 million victims of corneal blindness in China, Xinhua reported.
The research team from the Ocean University of China (OUC) was expected to produce a complete cornea and begin clinical trials in three to five years, said Fan Tingjun, deputy dean of the College of Marine Life Science at the OUC.
An artificial cornea, each expected to cost 10,000 to 20,000 yuan (1,475 to 2,950 U.S. dollars), would provide an alternative for those patients anxiously 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 also playing a key role in creating vision, consists of three main layers -- the endothelium, stroma and epithelium.
The research 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, which added great difficulties to cell cultures, said Fan, whose team started their research in 2002.
Before 2002, many researchers throughout the world resorted to the cancer gene to stimulate the growth of endothelial cells during the culture.
"So their achievements couldn't apply to clinical therapies, but only for further research," Fan said.
After nine years of trial and error, the team successfully cultivated a large quantity of normal human endothelial cells with the assistance of supports made of human amnion.
An evaluation panel of top ophthalmologists described their breakthrough as "building up the first endothelial cell line in the world without risks of causing tumors", as written on the achievement evaluation certificate issued by the State Science and Technology Commission.
The researchers have transplanted the artificial endothelium to 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 outside dust and bacteria from reaching the eye, as well as absorb oxygen and cell nutrients from tears.
Although some of Fan's foreign counterparts 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, adding that the production of epithelium, which was comparatively easier, had been accomplished successfully years ago.
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 who became blind after their endothelium was damaged.
"The mass production of complete corneas will be launched after the artificial cornea passes the clinical trials," Fan said.