Swedish researchers have offered hope to patients suffering from corneal blindness and low vision, after developing an implant made of collagen protein from pig skin, which resembles the human cornea, and which has already restored sight to 20 people.
It is a pilot study by the Swedish Linköping University (LiU) and LinkoCare Life Sciences AB, published in Nature Biotechnologywhose results offer an alternative to transplanting donated human corneas, which are scarce in the countries where they are most needed.
“The results show that it is possible to develop a biomaterial that meets all the criteria to be used as a human implant, that can be mass-produced and stored for up to two years and thus reach more patients. This helps us get around the problem of a shortage of donated tissue and access to other treatments for eye diseases,” Neil Lagali, a professor in the Department of Biomedical and Clinical Sciences at LiU, one of the experts behind the study, said in a statement.
It is estimated that 12.7 million people in the world are blind because their corneas, the outermost transparent layer of the eye, are damaged or diseased. The only way to regain vision is to receive one from a human donor. But only one in 70 patients receives a transplant. Furthermore, most of those who need it live in low- and middle-income countries where access to treatment is very limited.
“The safety and efficacy of bioengineered implants have been at the core of our work,” said Mehrdad Rafat, the researcher and entrepreneur behind the design and development of the implants. He is an adjunct associate professor (lecturer) in LiU’s Department of Biomedical Engineering and founder and CEO of LinkoCare Life Sciences AB, which manufactures the corneas used in the study.
“We have made significant efforts to ensure that our invention is widely available and affordable for everyone. Therefore, this technology can be used in all parts of the world”, he assured.
Other advantages
To create an alternative to the human cornea, the researchers used highly purified pigskin-derived collagen molecules produced under strict conditions. The animal skin that is used is a by-product of the food industry, so it is easily accessible and economically advantageous, they argued.
Donated corneas must be used within two weeks, bioengineered corneas can be stored for up to two years.
The researchers also developed a minimally invasive approach to treat keratoconus disease, in which the cornea becomes so thin it can cause blindness. Today, in an advanced stage, it is surgically removed and replaced by a donated one and sutured, an invasive surgery that is only performed in larger university hospitals.
“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,” explained Neil Lagali, its author.
“The incision can be made with great precision thanks to an advanced laser, but also, when necessary, by hand with simple surgical instruments. In addition, it is not sutured. The method was first tested in pigs and was found to be simpler and potentially safer than a conventional transplant,” he added.
The surgical method and implants were used by surgeons in Iran and India, where many people suffer from corneal blindness and low vision, but where donated corneas and treatment options are significantly lacking. Twenty people who were blind or near loss of sight due to advanced keratoconus participated in the pilot clinical study.
“The operations were free of complications; the tissue healed quickly, and an eight-week course of immunosuppressive eye drops was sufficient to prevent rejection. The patients were followed up for two years and no complications were observed during that time”, share the scientists.
A larger clinical study followed by market approval by regulatory authorities is needed for it to be used.
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