Researchers have succeeded in designing eye implants from pig skin proteins, thus managing to restore the sight of 14 blind people.
Visual impairment due to corneal stromal disease affects millions of people worldwide. The loss of corneal transparency is among the leading causes of blindness worldwide. It can be treated by transplantation, but more than half of the world’s population does not have access to corneal transplantation due to a lack of infrastructure for tissue donation, and because of economic, cultural, technological, political and ethical. A new study may therefore revolutionize the fate of many patients, as it demonstrates the possibility of restoring patients’ vision. “using an approach that is potentially as effective, safer, simpler and more widely available than donor corneal transplantation”.
Researchers have bioengineered an implantable medical device as a substitute for human transplantation. As a raw material, they used pig tissue to form a purified collagen solution, which is already used in FDA-approved medical devices. This solution was used to design a hydrogel that mimics the human cornea. Surgeons made an incision in the patients cornea to thicken and reshape it so it could restore function.
Keratoconus, a disease of the cornea characterized by thinning, weakening and scarring of the stroma, is the main condition compatible with a corneal transplant. The experiment was carried out on twenty patients with keratoconus, 14 of whom had been rendered completely blind by this disease. Of the patients, three have completely regained their sight, and the rest have partially regained it. After two years, the patients’ bodies had not rejected the implants and they had no inflammation or scarring, thus validating the success of the transplant, as rejections occur the year following the operation.
Traditionally, human tissue is needed for corneal transplants. But there are few of them, because people have to volunteer to donate them after they die. Thus, this inexpensive and widely available substitute could democratize transplantation for the treatment of blindness.
“In general, the body handles pig tissue quite well”, said Dr. Uri Soiberman, assistant professor of ophthalmology at Johns Hopkins Medicine, who was not involved in the research. Xenografts are a big topic of debate within the scientific community. Last January, in the United States, David Bennett was the first man to receive a heart transplant from a genetically modified pig. Following the patient’s death, two months after the operation, the doctors revealed that the graft was contaminated with a porcine virus.