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PRESTON, UK: People with poor oral hygiene or gum disease may be at a greater risk of developing Alzheimer’s disease, a study led by the University of Central Lancashire’s (UCLan) School of Medicine and Dentistry has found. For their study, the researchers examined samples from the donated brains of ten people without dementia and ten people with dementia. The research found the presence of products from Porphyromonas gingivalis in the brains of dementia patients.
The bacterium is commonly associated with chronic periodontal disease. These bacteria enter the bloodstream through daily activities, such as eating, chewing and toothbrushing, and through invasive dental treatment in particular, and potentially enter the brain on a regular basis from there. The researchers proposed that every time the bacteria reach the brain they may trigger immune system responses by the already primed brain cells, causing them to release more chemicals that kill neurons. This could be one mechanism that leads to changes in the brain, which is typical of Alzheimer’s disease, and could be responsible for causing symptoms such as confusion and deteriorating memory.
The new research indicates a possible association between gum disease and individuals who may be susceptible to developing Alzheimer’s disease if exposed to the appropriate trigger.
The research benefited from donated brain samples provided by Brains for Dementia Research, a brain donation scheme supported by Alzheimer’s Research UK and Alzheimer’s Society. Finding P. gingivalis in the brains of dementia sufferers is significant, as its presence in the brains of Alzheimer’s disease patients has not been documented previously and the finding adds to a growing body of evidence that suggests an association between poor oral health and dementia.
These published research findings from human brain specimens are further supported by recent unpublished research on periodontal disease from the same group using animal models, which was carried out in collaboration with the University of Florida. This animal work has confirmed that P. gingivalis in the mouth finds its way to the brain once periodontal disease has become established.
Prof. John Crean, Dean of the School of Medicine and Dentistry, said: “Whereas previous studies have indicated a link between dementia and other bacteria and viruses such as the Herpes simplex virus Type I, this new research indicates a possible association between gum disease and individuals who may be susceptible to developing Alzheimer’s disease if exposed to the appropriate trigger. Research currently underway at UCLan is playing an active role in exploring this link, but it remains to be proven whether poor dental hygiene can lead to dementia in healthy people, which obviously could have significant implications for the population as a whole. It is also likely that these bacteria could make the existing disease condition worse.”
Dr Sim K. Singhrao, Senior Research Fellow at UCLan, said: “We are working on the theory that when the brain is repeatedly exposed to bacteria and/or their debris from our gums, subsequent immune responses may lead to nerve cell death and possibly memory loss. Thus, continued visits to dental hygiene professionals throughout one’s life may be more important than currently believed, with inferences for health outside of the mouth. To help us prove our hypothesis, we are hoping to use the Brains for Dementia Research tissue resource to examine brain tissue from people with both intact and compromised memory for whom relevant dental records are available. The research ultimately aims to determine whether P. gingivalis can be used as a marker, via a simple blood test, to predict the development of Alzheimer’s disease in at-risk patients.”
