Corneal thickness changes, arrows indicate postoperative implant contours.

Clinical trial restores vision in 20 patients with corneas from unlikely sources: ScienceAlert

In an exciting pilot clinical trial, an implant made from pigskin has restored vision in 20 people with corneal lesions. Many patients were blind before receiving the help of this bioengineered tissue.

Incredibly, after two years, all 14 blind people had full vision and 3 of them now have perfect 20/20 vision.

“This allows us to [a] There is a shortage of donated corneal tissue and other treatments for eye diseases,” said Neil Lagali, researcher in ophthalmology at Linköping University.

While some 12.7 million people have lost their sight due to corneal problems, only 1 in 70 people are able to receive a corneal transplant—the only way to restore vision.

Due to the high cost of providing these transplants and the short supply of donated corneas, most people in the world do not have access to effective treatment.

“We have made a huge effort to ensure that our invention will be widely used and affordable by all, not just the wealthy. That’s why this technology can be used all over the world,” said a biomedical engineer at Linköping University Mehrdad Rafat said.

To achieve this, Rafat and colleagues developed a new technique that does not require sutures, so physicians can perform implant procedures with less specialized conditions and equipment.

“The less invasive approach could be used in more hospitals, helping more people. With our approach, the surgeon does not need to remove the patient’s own tissue. Instead, a small incision is made through which the implant will be placed. The implant is inserted into the existing cornea,” Lagali explained.

What’s more, the materials used to make the implants are by-products of the food industry, and thanks to specially developed packaging and sterilization processes, the final product can be stored for up to two years. By contrast, donated human corneas must be used within two weeks.

Our corneas — the transparent screen at the front of our eyes that protect our iris and pupils — are mostly made up of different types of collagen. This structure gradually thins over time, causing it to bulge outward and distort our vision in a condition called keratoconus.

While the exact cause of this thinning is unknown, genetics, vigorous eye rubbing, and conditions such as hay fever, asthma, Down syndrome, and Ehlers-Danlos syndrome all increase the chance of developing keratoconus.

So the researchers purified collagen from pig skin to create a new corneal layer. They used chemical and photochemical methods to strengthen the normally soft material and make it more stable, resulting in a hydrogel they called Bioengineered Pig Structure, Double Cross-Linked (BPCDX).

Changes in corneal thickness, arrows indicate postoperative implant profile (bottom). (Rafat et al., natural biotechnology2022)

The researchers refined their technique in animal models and then developed a simple method to insert BPCDX into the recipient’s cornea without removing existing tissue.

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

The minimally invasive procedure leaves the corneal nerves and cell layers intact, allowing the wound to heal quickly.

BPCDX successfully remained transparent after implantation through a 2 mm incision. No scarring or adverse effects, no intensive treatment or further surgery; just eight weeks of treatment with immunosuppressive eye drops and bandages.

Bioengineered corneas checked all safety boxes.

After two years, participants from Iran and India had an average increase of more than 200 microns in corneal thickness, reduced curvature, and improved vision at least to that of conventional corneal transplants.

Based on previous research and unpublished data, the team reported that previous attempts to implant the biomaterial into the eye resulted in thinning, but the fortified pig cell collagen remained strong and kept the implant stable even after eight years.

“To the best of our knowledge, previous studies have not achieved complete corneal transparency in vivo, sufficient corneal thickening and flattening, or significant improvement in vision,” the researchers wrote in their paper, which the researchers wrote in their paper. wrote in the paper.

A larger clinical trial is currently planned, but if the pilot is any indication, the researchers hope to get more promising results that will help the new procedure gain regulatory approval.

“The results show that it is possible to develop a biomaterial that meets all the criteria for use as a human implant, which can be mass-produced and stored for up to two years, thereby benefiting more people with vision problems,” Lagalli said. concluded.

The study was published in natural biotechnology.

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