Biosynthetic cornea
Scientists from Canada and Sweden have demonstrated for the first time the safety of artificial cornea transplantation from biosynthetic materials, which can significantly improve vision without resorting to the use of donor material, according to an article published in Science Translational Medicine (Per Fagerholm et al., A Biosynthetic Alternative to Human Donor Tissue for Inducing Corneal Regeneration: 24-Month Follow-Up of a Phase 1 Clinical Study).
Today, more than 10 million people in the world live with a damaged cornea, which leads either to vision impairment or to complete blindness. The only way to restore their ability to see is to transplant a donor cornea – a very expensive operation that patients have been waiting for for years.
The shortage of donor corneal tissues has led to the fact that scientists have been looking for other ways of treatment for a long time. At the same time, the operation does not guarantee the restoration of vision, since no person can be insured against rejection of donor tissues. In such cases, doctors sometimes resort to transplanting synthetic corneas made of polymers. However, such products do not lead to tissue regeneration, and therefore are used very limited.
"While we are at the stage of testing a prototype, however, the results already prove that artificially manufactured corneas can take root in the human eye and stimulate its regeneration. Additional research will make this approach to restoring vision accessible to millions of people who have to wait for years for expensive donor material for transplantation these days," said the lead author of the publication, Dr. May Griffith, quoted by the press service of the Ottawa Hospital Research Institute in Canada.
Griffith's group tried to find a replacement for donor tissues and synthetic corneas by resorting to the use of biosynthetic tissues derived from human collagen synthesized by genetically modified microorganisms. Such recombinant proteins could, according to the idea of the authors of the article, be used to make corneas suitable for transplantation and able to take root in a new place.
As the work of scientists with collagen produced on a commercial basis by an American company has shown, this is quite real. In their experiment with ten volunteers, which lasted for two years, the scientists found that the new corneas, obtained on the basis of recombinant collagen, really take root well, promote the regeneration of the nervous tissues of the eye and lead to the restoration of vision.
In 9 out of 10 cases, tissue and nerve regeneration occurred, which indicates that the transplanted materials successfully took root in the bodies of patients. When using additional contact lenses, the degree of recovery in six volunteers was no worse than when using donor corneas.
None of the patients had tissue rejection and none of them had to undergo long–term suppression of immunity - the two main problems that doctors face when transplanting donor corneal transplants.
Now doctors have to improve the technology of transplantation, in particular, to solve the problem of sutures that make the surface of the cornea rough. In addition, the biosynthetic tissue is still too fragile and therefore suitable only for transplantation to patients with superficial corneal injuries, but not for cases when the inner layer – the endothelium - is destroyed. In this respect, donor tissues have a serious advantage, so the biosynthetic cornea requires serious refinement.
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the ABC magazine and other open sources.
27.08.2010