New technique to deliver stem cell therapy may help damaged eyes regain sight
7 December 2012
Engineers at the University of Sheffield have developed a combination of techniques to produce a disc of biodegradable material that can be fixed over the cornea. The disc is loaded with stem cells, which then multiply, allowing the body to heal the eye naturally.
The standard way of treating corneal blindness is a corneal transplant. Stem cell therapy has been successfully performed to repair damaged corneas; however, the current technique involves using donor human amniotic membrane as a temporary carrier to deliver these cells to the eye.
For some patients, the treatment can fail after a few years as the repaired eyes do not retain the stem cells, which are required to carry out ongoing repair of the cornea. Without this constant repair, thick white scar tissue forms across the cornea causing partial or complete sight loss.
The researchers have designed the new biodegradable discs to contain small pockets that are built into the membrane. This helps the cells to group together and act as a useful reservoir so that a healthy population of stem cells can be retained in the eye.
"Laboratory tests have shown that the membranes will support cell growth, so the next stage is to trial this in patients in India, working with our colleagues in the LV Prasad Eye Institute in Hyderabad," says Professor Sheila MacNeil.
"One advantage of our design is that we have made the disc from materials already in use as biodegradable sutures in the eye, so we know they won't cause a problem in the body. This means that, subject to the necessary safety studies and approval from Indian Regulatory Authorities, we should be able to move to early stage clinical trials fairly quickly."
Treating corneal blindness is a particularly pressing problem in low-income countries, where there are many instances of chemical or accidental damage to the eye but complex treatments such as transplants or amniotic membrane grafts are not available to a large part of the population.
The technique has relevance in higher-income countries such as the UK and the USA as well, according to Dr Frederik Claeyssens: "The current treatments for corneal blindness use donor tissue to deliver the cultured cells, which means that you need a tissue bank. But not everyone has access to banked tissues, and it is impossible to completely eliminate all risks of disease transmission with living human tissue.
"By using a synthetic material, it will eliminate some of the risk to patients and be readily available for all surgeons. We also believe that the overall treatment using these discs will not only be better than current treatments, it will be cheaper as well."
The project collaboration between the University of Sheffield and the LV Prasad Eye Institute is supported by a Wellcome Trust Affordable Healthcare in India Award. Watch a video about the project.
Image credit: GovEd Communications.
Ortega I et al. Combined microfabrication and electrospinning to produce 3D architectures for corneal repair. Acta Biomater 2012.