Say no more lynx eye. Researchers at the University of Linköping, in Sweden, have designed an implant based on pig skin collagen protein, which has improved the sight of 20 people suffering from one of the main corneal diseases, keratoconus. Among them, 14 were initially blind. All recorded an improvement in their vision, 3 even regained optimal vision (20/20). If the results are only those of the first phase of a pilot study, revealed in Nature Biotechnology on August 11, they remain encouraging and could follow up on larger clinical trials.
Faced with a serious shortage of donor corneas, the issue here is very important, because it would reduce the wait for many patients. “An estimated 12.7 million people are waiting for a donor cornea, with one cornea available for every 70 needed. With an incidence of more than one million new cases of corneal blindness per year, the severe shortage of donor corneas presents an unequal burden of blindness that is heavily skewed towards low- and middle-income countries in Asia, Africa and the Middle East. Middle East, alert scientists in the study. More than half of the world’s population does not have access to corneal transplantation due to a lack of infrastructure for tissue donation, collection, testing and eye banking.
The pigskin used is a by-product of the food industry. “We have gone to great lengths to ensure that our invention will be widely available and affordable to everyone, not just the wealthy. This is why this technology can be used in all regions of the world,” says in a press release Mehrdad Rafat, researcher and entrepreneur behind the design and development of the implants.
Less invasive operation
In addition to being economical and easy to access on the market, this bioartificial cornea can be “stored for up to two years and thus reach even more people with vision problems”, adds Neil Lagali, another researcher behind the study. By way of comparison, a human cornea from a donor must imperatively be used within two weeks.
But the feat is also that of innovative surgery. Researchers have developed a less invasive technique to treat keratoconus disease. “With our method, the surgeon does not need to remove tissue from the patient. Instead, a small incision is made, through which the implant is inserted into the existing cornea,” explains Neil Lagali, who led the research group that developed this surgical method. The incision of the cornea can be performed with great precision using a state-of-the-art laser, but also by hand with more conventional surgical instruments.
Prevent the risk of rejection
After two years of follow-up, none of the 20 patients presented adverse postoperative effects. “Transparency was maintained with no degradation, scarring, adverse reactions or events requiring hospitalization, intensive therapy or additional surgery, thus meeting safety criteria,” notes the study. Following a transplant, the fear is also that of rejection. And there again, the scientists had a nice surprise: an eight-week treatment with immunosuppressive drops was enough to prevent this risk. With a conventional transplant, medication is needed for several years.
In November, an ophthalmologist at the Fondation-Rothschild hospital in Paris, Eric Gabison, performed a 100% artificial corneal transplant for the first time in Europe. Suffering from a serious pathology, the patient had been transplanted six times, each time chaining rejections and infections, before this success.
In general, xenografts (with grafts from another species) involving pigs have multiplied in recent years. In Baltimore in January, a pig’s heart was transplanted into a 57-year-old man. Although he died two months later, this represents a world first and a major scientific breakthrough. This animal is one of the best donors for humans, due to its immunological proximity and the size of its organs.