The cornea is the clear front of the eye and its clarity is vital for the transmission of light to the retina for visual perception. The surface of the cornea is made up of a multi-layered epithelium, which is maintained by adult stem cells located in the periphery of the cornea, in aregion known as the limbus.
Limbal stem cell deficiency (LSCD) is an irreversible disease resulting from the loss of these corneal epithelial stem cells, or limbal stem cells (LSC), and results in severe ocular surface disease (OSD) characterised bt reduced vision or blindness, chronic ocular irritation and visual glare. The corneal epithelium that normally covers the corneal surface becomes deficient and is replaced by the surrounding conjunctival epithelium, resulting in a thickened, irregular, unstable epithelium, often with secondary neovascularisation, inflammatory cell infiltration and disruption of the basement membrane.
This is a pilot study examining the efficacy and safety of transplanting ex vivo expanded limbal stem cells on human amniotic membrane (AM) as a procedure to restore sight and relieve pain for patients with severe ocular surface disease (OSD) arising from limbal stem cell deficiency.
It aims to:-
-Generate the data required for reliable sample size calculations for subsequent studies.
-Evaluate all the practicalities and logistics of the study including the recruitment process, follow-up procedures, data collection and analysis
-Obtain information on actual recruitment rate
The study also aims to obtain answers to the following questions:-
-Is transplantation of ex vivo expanded corneal limbal stem cells feasible, efficient and safe?
-Does this procedure lead to improvements in vision quality of the ocular surface?
-How does this immunosuppression and limbal stem cell transplantation compare with using immunosuppression and amniotic membrane alone? (from UKCRN Portfolio)
Additional lay summaries...
Background and study aims:
The cornea is the clear front of the eye, and its transparency is vital to allow you to see properly. Special cells called limbal stem cells, at the edge of the cornea, are responsible for repairing any damage and keeping the cornea healthy and clear. If the cornea is very badly damaged or if there aren?t enough of these special cells, this can result in severe ocular surface disease (OSD), which causes blindness, chronic eye irritation and glare.
Human amniotic membrane (the innermost lining of the protective sac round a baby in the womb) is commonly used in the surgical treatment of OSD, as it has very similar biological and physical properties to the surface of the eye. It is also possible to grow limbal stem cells from a donated cornea in the laboratory on human amniotic membrane. Human amniotic membrane is routinely collected, at caesarean section birth, from consenting donors and stored at Tissue Banks approved by the Human Tissue Authority.
This study is to compare the use of limbal stem cells grown on human amniotic membrane with amniotic membrane on its own as a surgical treatment for OSD.
Who can participate?
You are eligible to take part in the study if you are an adult of either sex and have severe ocular surface disease affecting your sight, which is due to a lack of these special limbal stem cells.
What does the study involve?
A total of 20 patients will take part. Half of the patients will receive treatment with limbal stem cells grown on amniotic membrane and the other half will receive treatment with amniotic membrane alone. Neither you, nor your doctor, will know which treatment you have received, and the treatment will be assigned at random.
You will undergo eye surgery to remove the damaged part of your cornea and replace it with either limbal stem cells grown on human amniotic membrane or amniotic membrane on its own.
You will have an eye examination and vision test before your surgery and you will be asked to answer some quality of life questions from two standard questionnaires. You will have further eye examinations and vision tests on days 1, 2 or 3, 7 and 14 after surgery and also at 1, 3, 6, 9, 12 15 and 18 months after your surgery, to assess how well the treatment has worked.
What are the possible benefits and risks of taking part?
It is possible that transplanting limbal stem cells grown on amniotic membrane may prove to be a better treatment for OSD than amniotic membrane alone, but there is no guarantee that this is the case.
As with any surgical procedure there is a risk of infection while the wound is healing. You will be given antibiotic and steroid eye drops to promote healing and help prevent infection. There is also the possibility of rejection of the transplanted tissue but you will be prescribed drugs to minimise this risk. All drugs can cause side effects, although many patients never have them. It is possible you may feel sick, suffer from diarrhoea, abdominal pain, tiredness or excess hair growth. These drugs may also lower your resistance to infection.
Where is the study run from?
The study is being run at the Princess Alexandra Eye Pavilion in Edinburgh and the Tennant Institute of Ophthalmology in Glasgow.
When is the study starting and how long is it expected to run?
The study started in February 2012 and patient recruitment will run until 20 patients have been enrolled. Each patient will be followed up on the study for a period of 18 months after surgery.
Who is funding the study?
The study is funded by grants from the UK Stem Cell Foundation, the Chief Scientist Office and Scottish Enterprise.
Who is the main contact?
Jane Pelly (Trial Manager)
email@example.com (from ISRCTN)