“Nature” sub-issue: Scientists make pigskin into corneas, allowing blind people to regain light

A cornea made of pigskin collagen restored light to 14 blind people.

Writing | Ling Jun, Yan Xiaoliu

Source | “Medical Community” Public Account

In a study published Aug. 11 in Nature Biotechnology, scientists demonstrated a cornea made of pigskin collagen to make 20 14 patients with keratoconus regained their sight – including 14 who were already blind.

The results offer new hope for corneal disease patients worldwide by replacing traditional human corneal donation with bioengineered implants. As one of the serious blinding diseases, according to statistics, about 12.7 million people in the world are blind due to corneal diseases, but on average, every 70 people can wait for the opportunity of corneal transplantation.

The study’s lead author, Professor Neil Lagali, Department of Laboratory Ophthalmology, Linköping University, Sweden, said the newly developed biomaterial has the potential to meet all the criteria for a human implant while being capable of mass production , the storage period is up to two years, or it may solve the problem of corneal donation shortage.

Corea derived from pig skin

The human cornea is located at the front of the eye and has functions including transmitting light, refracting light and protecting the inner eye structures such as the pupil and lens. Keratoconus is characterized by a thinning of the cornea, which loses its natural shape and begins to bulge toward a cone, and a misshapen cornea can also affect vision.

In this study, conducted by a team of Biomedical and Experimental Ophthalmology at Linköping University in Sweden, scientists created a bioengineered cornea called BPCDX. They first dissolved pig skin tissue, extracted and purified pig skin collagen, and then chemically and photochemically enhanced the stability to form a contact lens-like, strong and transparent hydrogel as a corneal stroma replacement.

As far as the material itself is concerned, its advantage is that the raw material pig skin is readily available and inexpensive. At the same time, human donated corneas are usually used within 2 weeks, while BPCDX can be stored for more than 2 years after sterile packaging because it does not contain cells.

The treatment process is also different from traditional invasive surgery. The doctor does not need to remove the original diseased corneal tissue of the patient, but directly implants the BPCDX over the original corneal tissue through a 2 mm incision. on the cornea.

The director of the ophthalmology department of a tertiary hospital in Shanghai analyzed the “medical community”, and it is generally understood that this artificial cornea is a “lens”.

“When using this artificial cornea, the doctor only needs to make a small incision on the patient’s cornea with a laser, make a surgical tunnel, implant the artificial cornea, and the operation is completed. No stitches,” he said.

It can be clearly seen through imaging imaging that BPCDX fills in the lost thickness of keratoconus, while the corneal curvature returns to normal. In addition, BPCDX showed strong resistance to degradation in vivo and remained intact after 2 years of implantation in human eyes, so that the corneal thickness was always maintained.

Changes in corneal thickness, arrows indicate contours after implant BPCDX (bottom)

3 blind patients regained 1.0 vision

To test the clinical efficacy of BPCDX, scientists recruited 20 patients with keratoconus from Iran and India, 14 of whom were blind and 6 were near blind.

2 years after BPCDX implantation, central corneal thickness increased by an average of 285 ± 99 µm in Iranian patients and 209 ± 18 µm in Indian patients. — With a flattened keratoconus, scientists found that patients’ corrected vision improved significantly.

Specifically, the average corrected visual acuity recovered to 20/26 (about 0.8) for 8 Indian patients and 20/58 (about 0.35) for 12 Iranian patients. In addition, all 14 blind patients regained their vision, three of whom had a corrected visual acuity of 1.0.

“I remember when I had my first implant surgery, I stayed up all night waiting for the surgeon to inform me of the progress of the procedure,” said one of the researchers, Professor Mehrdad Rafat. ” Surprisingly, we got much better results than expected.”

The results show that the vision improvement after BPCDX implantation has reached a level comparable to that of human cornea transplants. In contrast, traditional corneal transplants require patients to take immunosuppressive drugs for several years. “But the implant from pigskin has a low risk of rejection because collagen is a protein made up of amino acids and does not contain any cells,” the researchers said.

Postoperatively, the 20 patients received immunosuppressive eye drops for only 8 weeks, and no rejections, scars or inflammation were observed during the 2-year follow-up.

In the next step, Prof. Neil Lagali and team plan to replicate the results of this study in 100 or more patients to get BPCDX approved by the government, with the ultimate goal of rolling it out globally Technology – especially in regions where organ transplant resources are extremely scarce.

“This is a very good product.” The aforementioned director of ophthalmology commented on the “medical community”. It can achieve large-scale mass production, there is no rejection problem, a smaller implantation wound and a relatively simple minimally invasive surgical method are all its advantages.

The drawback, however, is that the patient population to which BPCDX can be applied may still be limited. “The cornea of ​​keratoconus patients is not diseased, but deformed. For patients with other corneal diseases, this artificial cornea may not be suitable. The graft materials used after keratopathy are different, and some patients need to remove the full thickness. Cornea, get a brand new cornea,” he said.

The researchers also said that they will continue to explore whether the technology can be used to treat more eye diseases and increase individual adaptability to obtain greater efficacy.


[1]Eye implant made from pig skin restored sight in blind people, according to study, https://globalnews.ca/news/9055629/pig-skin-cornea-implants -blindness-study/

[2]Cornea made from pig collagen gives people who were blind 20/20 vision, https://www.newscientist.com/article/2333290-cornea-made-from- pig-collagen-gives-people-who-were-blind-20-20-vision/

[3]Could THIS be the way to reverse blindness? Pioneering cornea implant made from PIG’S SKIN restores sight in 20 visually-impaired people in promising trial, https://www.dailymail .co.uk/sciencetech/article-11105183/Cornea-implant-PIGS-SKIN-restores-sight-20-visually-impaired-people-promising-trial.html

Source: Medicine

Editor in charge: Tian Dongliang

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