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Meet the Researcher – Dr Kerrie Thomas

17 October 2022

Dr Kerrie Thomas is a Reader at the Neuroscience and Mental Health Research Institute (NMHRI) and Co-Director of the Hodge Centre for Neuropsychiatric Immunology. Her research looks to further our understanding of PTSD (Post-Traumatic Stress Disorder) and ultimately improve the way we treat this devastating condition.

Tell us a bit about your research

Nightmares, flashbacks, memory loss, insomnia: Post-Traumatic Stress Disorder (PTSD) is debilitating and currently we lack effective drugs to treat it.

Working with Professor Paul Morgan (BSc 1977, MBBCh 1980, PhD 1984), I received a Hodge Foundation grant to research a pilot project to find out whether targeting the complement system could help patients with PTSD.

Patients with PTSD suffer from what we call intransigent, inflexible fear memories. These memories are hard to process. They are intrusive and particularly vivid. We have found that when fearful memories are recalled – as they often are in those who have PTSD – there is a change in the
brain’s hippocampus (the memory hub). Particularly, there is a change in the complement system at work there.

The complement system is part of the immune system. It enhances the body’s removal of the causes of disease, and it ensures normal brain function, refining the connections between brain cells. Our project aims to explore the changes to the complement system in PTSD patients in more depth, in order to treat this disorder.

We are asking whether the communication could be two-way – as the complement system is impacted by fearful memories, could it also modulate fear memory, and therefore could it be a target for the treatment of PTSD?

Specifically, we are investigating the role of microglia, traditionally perceived as support cells, but more and more understood as significant in immune responses, activating the immune system.

We have already been able to show that a single systemic administration of a drug that reduces microglial activation can reduce fear memory long-term. This is the first evidence to show that reducing microglial activation after memory recall can reduce fearful memories and that time-limited treatments targeting microglia could prove to be effective in treating psychiatric disorders.

To learn more about what is going on underneath these findings, we are currently investigating whether blocking the complement signalling system produces similar results.

What is your hope for your research and how it might benefit patients in the future?

We hope we can continue with our research to help develop a new treatment for disorders associated with memory problems. Our work may also inform when to give the treatment and to which subpopulation, for the best chances of recovery. For example, there is a huge gap in our knowledge about whether drug treatments are equally effective in both sexes. Our own data indicate that similar effects of our drug are seen in males and females, but there are some small but important differences. We think this is an important area to focus on.

What inspired or interested you in this particular field of research?

I’ve always been interested in how the brain makes and uses memories. Despite over 100 years of experimental science, we still don’t fully understand the underlying biology in its full, wonderful complexity. However, we are in an exciting new era with new methods of visualising the brain in action, knowing its genetic landscape, and understanding how it interacts with other systems such as the immune and gut systems, to really be able to gain useful insights into health and disease. It’s a great privilege to be involved.

What are the benefits of working at Cardiff University?

The neuroscience academic community and the research resources are excellent – world class. Cardiff has created a relatively unique environment in which it’s easy to collaborate with colleagues across Schools through shared spaces and other funding initiatives.

What are you favourite things about Cardiff?

The green spaces in and around the city, its sense of identity through culture and sport, and the vast array of good food! It is great place to bring up a family. It’s a place that encourages community both inside and outside the University.

What would you say to donors and fundraisers who have helped support your research?

Thank you. Your donations are a vital part of the funding landscape. They provide the Seedcorn funding to help us researchers realise a new idea, taking it off the paper to show proof-of-concept through an experiment. Your support allows us to be truly creative and give us the chance to try new solutions to long-standing issues.

Find out more about neuroscience and mental health research at Cardiff University.