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Artificial cornea to be tried on humans

By Redazione

Patients suffering from damage to the cornea may soon no longer have to wait for human donor tissue, as part of the EU-funded CORNEA project, German researchers at the Fraunhofer Institute for
Applied Polymer Research (IAP) in Potsdam and the Regensburg University Hospital have developed an artificial cornea that may be tested on humans as early as the beginning of 2008.

‘Our artificial corneas are based on a commercially available polymer which absorbs no water and allows no cells to grow on it’, says IAP project manager Joachim Storsberg. Once the polymers
have been shaped, the edge of the cornea is coated with a special protein, which the cells of the natural cornea can latch onto, Strosberg goes on to explain. ‘This way, the cornea implant can
firmly connect with the natural part of the cornea, while the centre remains free of cells.’

So far it has proven difficult to produce suitable artificial corneas due to those conflicting requirements: While the implant has to grow firmly into the natural tissue, the centre has to
remain clear of cells, so as such cell growth would impair vision.

The protein used to solve this particular problem in the new implant can survive thermal sterilisation, the scientists point out, as it does not have the structure typical of large proteins.
Those would be destroyed during sterilisation, changing the material’s properties in the process. In addition, the optical front part of the implant is coated with a water-loving polymer, so as
to keep it moistened with tear fluid.

The new artificial cornea has already been tested in the laboratory, being implanted in rabbits. Those tests have produced promising results, the researchers say.

Cornea damage may occur due to congenital malformation, hereditary disease or corrosion. The common solution in this case is for a donor cornea to be transplanted. 40,000 people in Europe alone
hope for a corneal tissue donation every year as their only means of not losing eyesight, many in vain. Only 27,500 transplantations per year are carried out in Europe due to lack of donors
among other things.

While the original CORNEA project has just been completed, research in the area continues: Currently, the CORNEA ENGINEERING project, also supported by the European Community under the Sixth
Framework Programme (FP6), is trying to reconstruct a human cornea in vitro, using tissue engineering. Such a development would transform eye surgery and dramatically cut the number of
experiments conducted on animals, the project partners believe.

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