Science

Bioartificial cornea gives sight to the blind – Sciences et Avenir

Three blind men have gained normal vision (20/20) thanks to a new bio-artificial cornea made from pig cells. This is reported by a team from the University of Linköping in Sweden in the journal Nature Biotechnology. So far, this is only the result of an experimental study, the first stage of human trials, but it is very promising. Of the twenty patients recruited for this trial, all with advanced keratoconus, 14 became blind and all regained their sight.

12.7 million people are blind due to corneal damage

Keratoconus is a progressive disease with no known cause that gradually deforms the cornea. Therefore, this thin transparent shell of the eyeball no longer ensures the correct convergence of light to the retina, and vision deteriorates. In some cases, the deformation can be compensated for with special lenses; but in the later stages of disability, only corneal transplantation can resist. But whoever talks about transplants talks about human transplants and, inevitably, an extended waiting list for patients. According to a large survey conducted by French experts in 2016 in JAMA Ophthalmology, 12.7 million people are blind due to damage to the cornea. And only one in 70 patients who need a new cornea is eventually helped by a transplant.

Here, Swedish and Iranian ophthalmologists and bioengineers have developed an implant that looks like a real cornea, or almost. Collagen molecules have been extracted and purified from pig skin cells to stabilize them into a material strong enough to implant, similar to gelatin. The advantage here is also that the raw material is a readily available by-product of the food industry. “We have made great efforts to make our invention widely available and accessible to everyone, not just the rich. That is why this technology can be used anywhere in the world,” Mehrdad Rafat said in a statement. research and CEO of LinkoCare Life Sciences AB, which manufactures the implants used in the trial. According to the team, the graft can even be stored for up to two years before implantation, which compares to the two-week survival time of a human cornea transplant.

© Tor Balhed/Linköping University

The originality of the treatment tried here also lies in the surgical technique used: instead of removing the diseased cornea to replace it with an implant, it is inserted directly into the cornea with sutures. “The surgeon does not have to remove the patient’s own tissue. Instead, a small incision is made through which the implant is inserted into the existing cornea,” says Neil Lagali, professor of ophthalmology experimenting at Linköping University. “It’s a less invasive method that requires fewer resources and could be used in more hospitals, helping more people,” adds the person who led the research team.

“A biomaterial that meets all clinical criteria”

After two years of follow-up, scientists report no complications in the 20 recruited patients. All of them, including 14 blind people, partially or completely regained their sight, doing – at least outwardly – the same way as with human transplants. Better: Eight weeks of treatment with immunosuppressive eye drops was sufficient to prevent implant rejection, whereas with a conventional transplant years of follow-up were needed.

This is not the first time that vision has been restored in people with severe retinal damage. But none of them with such cost savings is likely to be used anywhere else but in the most affluent countries. Nearly three years ago, reprogrammed stem cells were successfully used to regenerate the cornea of ​​a patient in Japan. In 2021, a Rothschild Foundation hospital in France announced the first transplant in Europe of a 100% artificial cornea to a blind patient. An indication that the development of these keratoprostheses is on the rise.

“Our results show that it is possible to develop a biomaterial that meets all clinical criteria, that can be mass-produced, stored for up to two years, and thus reach even more people with vision problems,” said Neil Lagali again. However, it remains for his team to demonstrate this in larger clinical trials and then, after possible approval, go to market.

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