Understanding the links between gum disease and brain health: Why is periodontitis a risk factor for dementia

Code: BC-DTP_2026_64

Title: Understanding the links between gum disease and brain health: Why is periodontitis a risk factor for dementia

Primary Supervisor: Simon McArthur

Email: s.mcarthur@qmul.ac.uk

Institute: Institute of Dentistry

Secondary Supervisor: Abish Stephen

Email: a.s.stephen@qmul.ac.uk

Institute: Institute of Dentistry

Lay Summary:

Periodontitis, chronic inflammation in the gums and jaw, is very often undiagnosed, despite affecting almost half of all adults in the UK. As well as potentially leading to tooth loss, periodontitis is a risk factor for major diseases including diabetes, heart disease and dementia. We do not understand the underlying reasons for these links however, so designing interventions to break them is very difficult. 

Our research group has gathered preliminary evidence suggesting that the bacteria P. gingivalis, a major driver of periodontitis, may be an important culprit. We have shown that this bacterium produces chemicals that damage experimental models of brain blood vessels, causing changes very similar to those seen in patients with dementia, and that are known to increase the brain’s vulnerability to inflammation and other challenges. 

This PhD project will take this work forward in three ways: 1) Studying the biological pathways by which P. gingivalis-derived chemicals damage brain blood vessels, 2) Investigating the consequences of these molecules for brain and behaviour in mice, and 3) Collecting oral samples and testing memory function in individuals attending periodontitis clinics at the Royal London Dental hospital, to verify the links proposed in our experimental work. 

The PhD student will gain a range of skills in laboratory, pre-clinical and clinical research, including in liaising with patients and the public. Together, this will help build a picture of how periodontitis can affect the brain, identifying points where interventions can be made to break the links between gum and brain disease.

Aims

1. To determine the mechanism of action of organosulfur compound-mediated damage to BBB function in vitro, combining bioinformatic analyses with signalling pathway studies.
2. To extend our in vitro findings to an in vivo murine model of periodontitis, comparing the relative ability of wild-type or mutant, organosulfur-non-producing, P. gingivalis strains to affect BBB function, neuroinflammatory parameters and cognitive function.
3. To extend our preclinical analyses to a human context, analysing the relationship between periodontal disease, circulating organosulfur compound levels and cognition in patients attending periodontitis clinics at the Royal London Dental Hospital.

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