According to a study by Gain and colleagues published in JAMA Ophthalmology, an estimated 12.7 million people are on a waiting list for cornea transplants, which is the only curative treatment for corneal blindness. Only one in 70, however, is able to get the surgery. Furthermore, most patients who are in need of the surgery, which requires a human donation, are in low and middle-income countries in Asia, Africa and the Middle East.
Fortunately, a recent study published in Nature Biotechnology by Rafat and colleagues could provide a new and less invasive alternative to human corneal donation for corneal blindness patients. The researchers in the paper were from Linkoping University and LinkoCare Life Sciences, and they were able to return vision to 14 blind patients with a special corneal implant made from medical-grade collagen from pig skin, a purified food industry product that is used in US FDA-approved medical devices to treat glaucoma.
Donor availability is not the only limitation with the typical treatment for those with corneal blindness. The typical treatment also requires a physician to surgically replace a cornea and sew it into position, which carries the risks of graft rejection, healing complications, infections, astigmatism and a need for long-term support. With this new method of using pig skin protein, however, no stitches are required when inserting the implant into the existing cornea; additionally, the incision is minimally invasive with either an advanced laser or by hand.
A press release for the study stated: “The operations were free from complications; the tissue healed fast; and an eight-week treatment with immunosuppressive eye drops was enough to prevent rejection of the implant. With conventional cornea transplants, medicine must be taken for several years. The patients were followed for two years, and no complications were noted during that time.”
The scientists found that the patients’ new corneas were restored to normal, and their sight improved as much as it would have done with the typical cornea transplant, if not more. Bioengineering implantable tissues such as pig skin is a key to addressing the global burden of corneal blindness. Not only does the procedure provide promising results, but the new corneas can also be more accessible as they can be stored much longer than typical organ donations – two years, compared with two weeks for human organ donations. This is because the new corneas are packaged and sterile and do not require pathogen testing if there were viral outbreaks, according to the study.
Despite these results, the researchers still need to perform a larger clinical study before could the product can be formally approved and used in healthcare. “We’ve made significant efforts to ensure that our invention will be widely available and affordable by all and not just by the wealthy,” Mehrdad Rafat, the researcher and entrepreneur behind the design and development of the implants, said in a press release. “That’s why this technology can be used in all parts of the world.”