Every year in France, you have to 8,000 corneas to cover corneal transplant needs Population. Given the shortage of donors, medical teams have to import around 1,600 corneas each year. To better meet the demand for corneas, researchers are trying to develop other types of transplants, including corneal transplants from pig cells. A recent study has just been published on this subject in the scientific journal Nature Biotechnology.
8,000 corneal transplants each year in France
Corneal transplantation, scientifically called full-thickness keratoplasty, aims to replace a pathological cornea, with opacity impacting vision, with a healthy cornea. There are many indications for corneal transplantation:
- Bullous dystrophies occurring following cataract surgery, which represent between 20 and 50% of transplants. The optimization of cataract surgery techniques might reduce corneal transplants in this indication in the coming years;
- Keratoconus, a progressive disease that causes a progressive deformation of the cornea. This cause can account for up to 30% of corneal transplants;
- Infectious keratitis, inflammatory diseases of the cornea linked to an infection, in particular by the Herpes virus;
- Fuchs dystrophy and hereditary dystrophies are rarer causes;
- Corneal graft failures, which lead to repeat surgery;
- As well as corneal scarring following severe eye trauma.
This intervention allows the patient to regain vision, with an 85% probability of success. In addition, as with any transplant, the patient must take preventive treatment once morest graft rejection. This treatment includes corticosteroids and immunosuppressants.
Towards an alternative to corneas taken from a deceased donor
Nowadays, corneal transplants are performed from healthy corneas, taken from a deceased donor. However, in recent years, an increasing number of families have been reluctant to accept this type of organ harvesting, which contributes to the recurrent lack of available grafts. For researchers and doctors, another possibility would be to turn to other types of grafts: grafts of animal origin, synthetic grafts, a mixture of a synthetic substrate and human cells.
This potential breakthrough in corneal transplantation is the subject of active research, as evidenced by the recent published study on corneal transplantation from pig cells. In this study, researchers developed a corneal tissue obtained from a synthetic substrate associated with cells of porcine origin. They carried out a pilot clinical trial in India and Iran, to implant this corneal tissue, with a minimally invasive method, in 20 patients with an advanced form of keratoconus.
Improved vision and good tolerance
In this novel form of corneal transplant, doctors did not remove existing corneal tissue or suture. They returned the cornea to normal shape by implanting the synthetic corneal tissue. The patients thus transplanted were followed over a period of 24 months, without any adverse event occurring.
At the end of the follow-up period, the researchers observed an improvement of :
- Corneal thickness (average increase of 209 µm in India, 285 µm in Iran);
- Keratometry measurements (measurement of the radius of curvature of the cornea);
- Visual acuity.
All 14 patients who were blind at the time of their inclusion in the study saw their vision improve and were able to wear contact lenses to improve their visual abilities. The results of this study suggest that the use of a synthetic cornea made from porcine cells might be an interesting alternative to corneal transplantation from human cornea. A solution that might be developed in the coming years to better meet the needs of patients.
Estelle B., Doctor of Pharmacy
Sources
– The corneal transplant (keratoplasty penetrating). snof.org. Accessed September 21, 2022.