LINKÖPING, Sweden — A protein implant derived from pig skin could restore a blind person’s vision, according to a new study. Researchers found no one who underwent the operation still dealt with blindness two years later. Moreover, three people who were blind ended up with 20:20 vision after the groundbreaking procedure.
The implant, made out of collagen protein from a pig’s skin, resembles the human cornea — the outermost transparent layer of the eye.
Damaged or diseased corneas cause blindness in more than 12 million people around the world. Typically, doctors can only restore these patients’ vision by performing a human cornea transplant from a donor. However, just one in 70 people who need a cornea transplant can get one.
Researchers say this new transplant is capable of mass production and has a shelf life of two years, while donated corneas from humans must reach patients within two weeks. The new technology could help people in poorer countries where human corneal transplants are especially rare.
New transplant significantly cuts recovery time
For the study, a team from Sweden recruited 14 blind people and six partially sighted people in India and Iran. Participants suffered from the disease keratoconus, where the cornea becomes so thin it can lead to blindness.
Study authors found none of the 14 participants who had been blind before they had the operation were still blind afterwards. Three of the Indian participants who were blind ended up with perfect vision after the transplant. No one reported any complications during the operation or after a two-year follow-up.
Just an eight-week course of eye drops was enough to stop a patient’s eye from rejecting the implant. With conventional corneal transplants, it can take several years of medication before experiencing full recovery.
Making corneal transplants ‘widely available and affordable’
The main purpose of the study was to work out whether the implant was safe to use. The team notes the effectiveness of the transplant was stunning. To make it, the team used collagen molecules coming from pig skin that were highly purified and produced under strict conditions for human use. The pig skin is not the same as the kind the meat industry uses, making it easy to access and economically advantageous.
When researchers constructed the implant, they stabilized the loose collagen molecules to make a robust and transparent material that could withstand handling and implantation in the eye. A larger clinical trial must take place before scientists can declare it to be safe and effective enough to roll out in hospitals.
“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. This gets us around the problem of shortage of donated corneal tissue and access to other treatments for eye diseases,” says Professor Neil Lagali from Linköping University in a media release.
“Safety and effectiveness of the bioengineered implants have been the core of our work,” says Dr. Mehrdad Rafat from LinkoCare Life Sciences AB, who designed and developed the implant.
“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.”
Getting rid of dangerously invasive surgeries for the blind
The team has also developed a new, minimally invasive method for treating keratoconus. Today, a keratoconus patient’s cornea at advanced stage is surgically removed and replaced by a donated cornea, which doctors sew into place using stitches. This kind of surgery is invasive and only done at larger hospitals. Stitches are unnecessary with this new surgical method.
The incision in the cornea can be made accurately using an advanced laser or by hand with simple surgical instrument. The method was first tested on pigs and turned out to be simpler and potentially safer than a conventional cornea transplant.
“A less invasive method could be used in more hospitals, thereby helping more people. With our method, the surgeon doesn’t need to remove the patient’s own tissue. Instead, a small incision is made, through which the implant is inserted into the existing cornea,” says Lagali.
The findings are published in the journal Nature Biotechnology.
South West News Service writer Mark Waghorn contributed to this report.