Exosomes and “Stemness”

Fight for Sight, Glaucoma UK, and Health and Care Research Wales are funding the work of Cardiff University, Wales, researchers, who demonstrated that bone marrow stem cells can prevent the death of retinal ganglion cells in animal models of glaucoma (1). Now, the researchers want to focus on stem-cell derived exosomes (the extracellular vesicles that transport proteins and genetic information between cells) to replicate the same benefits – while avoiding the risks of injecting cells into the eye. We speak to Ben Mead, Assistant Professor at the School of Optometry and Vision Sciences, Cardiff, Wales, to find out more. 

Why did you decide to pursue this lane of research?
Around 10 years ago, I was investigating stem cell therapies and was fascinated by their ability to promote repair of damaged tissues without replacing lost cells. I found that, despite the name stem cell, it is not their “stemness” that is responsible for their effectiveness, but rather their ability to release a large amount of positive therapeutic factors.

What makes bone marrow cells suitable for a potential therapeutic – and are there any drawbacks?
These cells are naturally pro-regenerative and are involved in many repair-related roles in the body. They secrete a steady supply of therapeutic factors – essentially acting as “mini-factories” that pump out a cocktail of positive compounds as well as a substantial number of exosomes. Notably, exosomes appear to mediate much of the therapeutic effects of stem cells. Another benefit of using adult stem cells is that they are free of much of the ethics associated with stem cells.

The main downside is that they are a dividing cell, which, when injected in the eye, could continue dividing. And that’s why we have adopted a cell-free approach, harvesting and then purifying the positive secretions of the stem cells before delivery into the eye.

Could this approach be used to address other retinal diseases in time?
We are currently investigating this question, but we do believe other retinal diseases are amenable to stem cell-derived exosome treatment.

What are the next steps for your research – and what are your expectations for the future?
The next steps are to test different types of stem cells/stem cell-derived exosomes, including those derived from adipose tissue, umbilical cord blood, and wisdom teeth. We aim to find the most therapeutically efficacious formulation to take forward into clinical testing.