Laboratory-derived porcine collagen cornea restored vision in blind people

Scientists in Sweden have developed an implant made from pig skin collagen that resembles the human cornea of the eye. The experimental implant significantly improved or restored vision in 20 people with a defective cornea, most of whom were previously blind. In some cases, the restoration of vision was complete (20/20 score).

The researchers from LinkoCare Life Sciences AB and LinkoCare University, who published the paper in the biotechnology journal Nature Biotechnology, hope that their achievement will give hope to those suffering from corneal vision loss or blindness by offering them a biomechanical implant as an alternative to donor human corneal transplantation. Such grafts are often rare.

«Our results show that it is possible to develop a biological material that meets all the criteria for use as human implants, which can be mass produced and stored for up to two years, so it will be available to even more people with visual impairments. This allows us to overcome the problem of a lack of corneal tissue from donors,» said Professor Neil Lagali of the Department of Biomedical and Clinical Sciences at Linkeping.

An estimated 12.7 million people in the world are blind due to their cornea, the outer transparent layer of the eye, which can be damaged by disease or injury. So far, the only way to restore vision is through transplantation, but this happens to only one in 70 patients. In addition, most people who need such a transplant live in low and middle-income countries, where access to transplants is de facto very limited.

«The safety and efficacy of biotechnology implants are at the core of our work. We have made significant efforts to ensure that our invention is made widely available and cheap for everyone, not just the rich. That is why this technology can be used in all parts of the world,’ said Associate Professor Mehrad Rafat of the Department of Biomedical Engineering at Linköping, designer of the implants and founder and CEO of LinkoCare Life Sciences AB, the company that produces them.

The human cornea is composed mainly of the protein collagen. To create the laboratory cornea, the researchers used collagen molecules from pig skin (a by-product of the food industry that is widely available and cheap), which were purified and mass-produced for human use. The end result is a durable and transparent material that can be transplanted into the eye. While donor corneas must be transplanted within only two weeks, laboratory corneas have up to two years after they are created.

Researchers have also developed a new minimally invasive method for treating keratoconus, a condition in which the cornea becomes so thin that it can lead to blindness. Until now, a patient's advanced-stage keratoconus has to be surgically removed and replaced with a donor graft, through a procedure that is invasive and only done in specialised medical centres.

«A less invasive method can be used in more hospitals, which will therefore help more people. With our method, a surgeon does not have to remove the patient's tissue. Instead, through a small incision made by laser or manually, the implant is inserted into the existing cornea,» said Dr. Lagali.

The technique was first successfully tested in pigs and then piloted in 20 people in Iran and India (two countries with large numbers of corneal blindness patients), where it proved to be simpler and safer than a conventional corneal transplant. The laboratory implant insertion procedures did not show any complications and a treatment of only eight weeks with immunosuppressive drugs (drops) - rather than years as in the case of conventional transplantation - was enough to prevent rejection of the implant. Its thickness and curvature were restored to normal levels.

Before the operation 14 of the 20 patients were blind, and after two years none of them were blind anymore. In fact, three of those who were blind before had perfect vision after the operation (20/20).

Researchers are not yet sure what the final cost of the new method will be, but they estimate that it will be lower than a normal transplant. However, a larger clinical trial needs to be carried out before the new method can be authorised by the regulatory authorities. Also to be investigated is whether the new technology can be used in other eye diseases, and whether the implant can be made more effective through personalised tailoring to each patient.