Research Focus- Limbal stem cells

The cornea is the clear front of the eye and its clarity is vital for the transmission of light to the retina at the back of the eye for visual perception. The surface of the cornea is composed of an pithelium, and this is continuous with that of the surrounding conjunctiva. The transition between the corneal and conjunctival epithelia is formed by the limbal epithelium, and this harbours the stem cells for the corneal epithelium, the so-called limbal stem cells.

Limbal stem cell deficiency is an ocular surface disease characterised by the loss or dysfunction of limbal stem cells. It results from a variety of causes, including hemical and thermal burns to the eye, contact lens related eye disease, hereditary diseases (such as aniridia and ectodermal dysplasia), and inflammatory diseases
(such as Stevens-Johnson syndrome and ocular cicatricial pemphigoid).

The major research areas for the limbal stem cell project are:

1. Identification of limbal stem cell markers – To date there are no known specific limbal stem cell markers. A major component of the project involves the investigation of new limbal stem cell markers, especially those which can be found on the cell surface.

2. Investigation of the limbal stem cell microenvironment – The environment which supports limbal stem cell survival is also being investigated. This can give important clues about the signalling mechanisms which maintain the limbal stem cells. This will not only aid in the identification of new limbal stem cell markers, but may enable the development of new growth promoting strategies for limbal stem cells.

3. Culture of limbal stem cells – A major new treatment for limbal stem cell deficiency is the culture and expansion of limbal stem cells for the purposes of transplantation in patients with limbal stem cell deficiency. This area of research forms another major component to the project. The cells will be grown in animal
free conditions under Good Manufacturing Practice specifically for therapeutic purposes.

4. Transplantation of limbal stem cells – The main aim of the project is the identification of new treatment strategies for limbal stem cell deficiency. These include the transplantation of expanded limbal stem cells and the use of growth promoters to expand any surviving limbal stem cells. These new treatments are currently being investigated in the form of a clinical trial sponsored by the MRC UK.

This is a collaborative effort between Prof Majlinda Lako and myself.