Clinical trial restored sight to 20 people with corneas made from unlikely source: ScienceAlert

Implants made from pigskin restored sight to 20 people with diseased corneas in exciting pilot project clinical test. Many patients were blind before receiving help from this bio-engineered fabric.

Incredibly, after two years, these 14 blind people have had their vision restored and three of them, and three of them now have perfect 20/20 vision.

“This allows us to circumvent the problem of [a] the shortage of donated corneal tissue and access to other treatments for eye disease,” said Neil Lagali, researcher in ophthalmology at Linköping University.

While approximately 12.7 million people suffer vision loss due to corneal problems, only 1 in 70 manage to receive a corneal transplant – the only way to restore their vision.

Because the means to provide these transplants are expensive and cornea donations are rare, most people in the world do not have access to effective treatments.

“We have gone to great lengths to ensure that our invention will be widely available and affordable to everyone and not just the wealthy. That is why this technology can be used in all parts of the world,” said Mehrdad Rafat, biomedical engineer from Linköping University.

To achieve this, Rafat and his colleagues developed a new technique that requires no stitches so doctors can perform the implant procedure with less specialized conditions and equipment.

“A less invasive method could be used in more hospitals, helping more people. With our method, the surgeon does not need to remove the patient’s own tissue. Instead, a small incision is made, through which the implant is inserted into the existing cornea,” Explain They lied.

Additionally, the material used to create the implant is a by-product of the food industry, and thanks to specially developed packaging and sterilization processes, the final product can be stored for up to two years. In contrast, donated human corneas must be used within two weeks.

Our cornea – the clear shield on the front part of our eye that protects our iris and pupil – is mostly made up of different types of collagen. This structure can gradually thin over time, causing it to bulge outward and distort our vision in a condition called keratoconus.

Although the exact cause of this thinning is not known, genetics, vigorous eye rubbing, and conditions such as hay feverasthma, Down syndrome and Ehlers-Danlos syndrome can increase the risk of developing keratoconus.

The researchers therefore purified the collagen from pig skin to create a new layer of cornea. They used chemical and photochemical methods to strengthen this usually soft material, making it more stable, resulting in a hydrogel they called a bioengineered, double cross-linked porcine construct (BPCDX).

Changes in corneal thickness with arrows indicating the contours of the implant after the operation.
Changes in corneal thickness with arrows indicating the contour of the implant after the operation (bottom). (Rafat et al, Natural biotechnology2022)

Refining their techniques in animal models, the researchers then developed a simple method to insert BPCDX into the recipient’s cornea, eliminating the need to remove existing tissue.

Here, the implant flattens the buckling of the cornea and provides the lost thickness, repairing the eye’s ability to focus.

Minimally invasive surgery leaves the corneal nerves and cell layers intact, allowing the wound to heal quickly.

After implantation through a 2 mm incision, the BPCDX successfully remained transparent. There was no scar formation or adverse reaction, and no intensive therapy or other surgery was required; just an eight-week treatment with immunosuppressive eye drops and a bandage.

The bio-engineered cornea has checked all the security boxes.

After two years, participants from Iran and India experienced an average increase of more than 200 micrometers in the thickness of their cornea and a decrease in its curvature, improving their vision at least to the extent of traditional corneal transplants. .

Previously attempted biomaterial implants in the eye eventually thinned, but the fortified pig cell collagen remained strong and kept the implant stable even after eight years, the team reported. based on their previous studies and unpublished data.

“No previous study has, to our knowledge, achieved complete corneal transparency in vivo with sufficient thickening and flattening of the cornea, or with significant visual acuity gains as shown here,” the researchers said. written in their diary.

A larger clinical trial is now planned, but if the pilot is any indication, researchers are hoping for additional promising results that will help the new procedure meet regulatory approvals.

“The results show that it is possible to develop a biomaterial that meets all the criteria to be used as a human implant, which can be mass-produced and stored for up to two years and thus reach even more people with health problems. vision”, Lagali concludes.

This research was published in Natural biotechnology.

Leave a Comment