A team of scientists say they’ve found a new way to help people with damaged corneas: bioengineered implants created from pig skin. In findings from a small clinical trial published this month, the implants were shown to restore people’s eyesight for up to two years, including in those who were legally blind. Should it continue to show promise, the technology may one day provide a mass-produced alternative to donated human corneas for people with these conditions.
The cornea is the transparent outer covering of the eye. In addition to protecting the rest of the eye, it helps us see by focusing the light that passes through it. Corneas can heal from mild abrasions easily enough, but more serious injury and certain diseases can leave behind permanently damaged corneas that start to impair our eyesight. Around 4 million people are thought to suffer from vision-related problems caused by injured corneas, according to the World Health Organization, and it’s one of the leading causes of blindness.
For those with severely damaged corneas, the only truly effective treatment is a transplant of a healthy cornea, also known as a corneal graft. Unfortunately, like many organs, human corneas have to be used very soon after they’ve been donated, and they’re often in short supply, especially for people living in poorer countries. That scarcity has fueled efforts by researchers to find other methods to replace or support damaged corneas. One such approach is the implant created by researchers from Linköping University (LiU) in Sweden, who have also founded the company LinkoCare Life Sciences AB to further develop it.
In their research, published last week in Nature Biotechnology, the team gave their implant to 20 patients from India and Iran with advanced keratoconus, a condition where the cornea progressively thins out. Nineteen of 20 patients experienced substantial improvements to their eyesight afterward, with all 14 people who were legally blind no longer meeting that threshold. The patients who needed further corrective treatment were also now able to tolerate contact lenses again. And these gains remained stable two years after, while no adverse events were reported.
“The results show that it is possible to develop a biomaterial that meets all the criteria for being used as human implants, which can be mass-produced and stored up to two years and thereby reach even more people with vision problems,” said study author Mehrdad Rafat, a professor at LiU’s Department of Biomedical Engineering and CEO of LinkoCare, in a statement from the university.
There are existing artificial corneas in use, as well as similar treatments in development. But the researchers say their implant should have some key advantages over these options. Many of these treatments still rely on donated corneas to reduce the risk of rejection by the body, while the team’s implant instead uses relatively cheap biosynthetic material derived from purified pig skin. The material is then used to create a thin but durable layer of mostly collagen, the same basic ingredient of the cornea. In the current study, the patients were only given eight weeks of transplant drugs to ensure acceptance by the body, as opposed to the year or more of medication typically given to those with cornea grafts, and no signs of rejection were reported.
They’ve also developed a less invasive method of surgery to insert their implant, one that doesn’t need to remove the original cornea, which should reduce the risk of complications and allow for broader use in places with fewer resources. And other research of theirs suggests that the materials in the implant should remain stable for at least eight years, if not longer.
“We’ve made significant efforts to ensure that our invention will be widely available and affordable by all and not just by the wealthy. That’s why this technology can be used in all parts of the world,” Rafat said.
Of course, these findings are still very small in scope. It will take successful results seen in many more patients before any country would think to approve this treatment. To that end, the researchers are planning larger clinical trials of their implant, and they may broaden their work to see if the treatment can work for other cornea-related conditions.