What makes so many corneal donor stem cell transplants fail?

Overview

The cornea is the clear surface that’s shaped like a dome and covers the front of the eye. It is made up of different types of cells arranged in several layers. They act together to protect the eye and provide clear vision. 

These cells can regenerate themselves continuously thanks to a small number of stem cells located on the surface of the eye. Stem cells are cells with the ability to produce more of themselves (by splitting in two) and become a different type of cell with a specific job to do in the body. 

Being exposed to chemicals or a variety of disorders can damage these stem cells. People with damaged stem cells can’t regenerate the surface of the eye, which means it stops being clear and leads to sight loss. It also causes pain or discomfort. 

The only treatment that can restore sight is a transplant to replace the damaged stem cells. If both eyes are damaged then the stem cells must be taken from a donor. However, success rates for donor stem cell transplants are very poor. Researchers think this is because the donor stem cells are often rejected by the immune system.  

In this project the team is collecting stem cells from donor corneas to see whether they produce molecules or proteins that could potentially trigger rejection by the immune system. They are also testing whether rejection actually happens, by mixing human immune cells called lymphocytes with donor corneal stem cells in a laboratory dish and watching to see if the lymphocytes kill or damage the stem cells. They hope to understand how to prevent donor stem cell rejection and to take that knowledge to the clinic.