In a new study, published in the journal Acta Biomaterialia, a team of experts detail their technique for creating membranes to help in the grafting of stem cells onto the eye, a way to imitate attributes of the eye. This technology has been developed to treat injuries to the cornea, the see-through layer on the front of the eye, one of the biggest causes of blindness around the world.
The research team used methods known as microstereolithography and electrospinning to create a disc of biodegradable material which can be placed over the cornea. The disc is then filled with stem cells which multiply, permitting the eye to be fixed naturally.
EPSRC Fellow, Dr Ílida Ortega Asencio, from Sheffield's Faculty of Engineering, says:
"The disc has an outer ring containing pockets into which stem cells taken from the patient's healthy eye can be placed. The material across the centre of the disc is thinner than the ring, so it will biodegrade more quickly allowing the stem cells to proliferate across the surface of the eye to repair the cornea."
An important quality of the disc is that it has pockets to store and protect the stem cells, simulating niches found around the rim of an undamaged cornea. Regular treatments for corneal blindness are corneal transplants, also known as grafting stem cells, onto the eye with the human amniotic membrane from a donor, used as a short-term delivery method for these cells to reach the eye.
Occasionally, this treatment can stop working after several years - the fixed eyes do not retain these stem cells, which should be repairing the cornea continuously.
If this continuous repair does not take place, thick white scar tissue can develop across the cornea, resulting in partial or total vision loss.
The investigators have created the small pockets that are formed in the membrane to aid cells to combine and act as a beneficial storage supply of daughter cells, so that a healthy group of stem cells remain in the eye.
Professor Sheila MacNeil explains:
"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.
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."
In the developing world, corneal blindness treatment is a growing issue where accidental or chemical damage to the eye are commonplace. However, intricate treatments like amniotic membrane grafts and transplants are simply no available for most people.
This method is more realistic in developed countries, such as the United States or the UK. Current methods for treatment require access to a tissue bank, which some countries do not have access to. It is also nearly impossible to completely prevent human tissue related disease.
The authors suggest that by using a synthetic material, the risks are removed and the material is readily available to surgeons. Using the discs will not only be better than current treatment, it will also be less expensive.
Scientists at the UK Stem Cell Foundation are currently researching on the use of stem cell treatment to cure vision loss caused by glaucoma, another major cause of blindness worldwide.
Written by Kelly Fitzgerald