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Center for Cognitive Health

Does Periodontal Bacteria Cause Alzheimer’s Disease?

We have been taught the importance of brushing our teeth since childhood, but could maintaining healthy oral hygiene protect us from getting Alzheimer’s disease? The human mouth is home to at least six billion bacteria! [2]

A recent study published in Science Advances claims that the oral pathogen Porphyromonas gingivalis can travel from the mouth to the brain, where it may instigate Alzheimer’s disease. They have found that people with Alzheimer’s disease have higher levels of the bacterial protease gingipain in their brain tissue, which is produced by the bacterium P. gingivalis. They also found that the brains of people with Alzheimer’s disease contain traces of gum bacteria that may initiate or aggravate Alzheimer’s disease pathology. [1] See the full publication here.

The study suggests that once in the brain, the P. gingivalis bacteria releases toxic proteins, gingipains, that have been shown to destroy neurons and cause other signature signs of Alzheimer’s disease in the brain in animal studies. Once the brain is infected, the brain’s natural defenses gather around the infected cells causing the inflammation and buildup of plaques associated with Alzheimer’s disease.[4]

What is Porphyromonas gingivalis?

P. gingivalis is most commonly associated with degenerative gum disease. In the U.S., periodontal disease affects one-half of the population over 30 years of age and is the major cause of tooth loss among adults. [6] Studies show that older people with periodontal disease have an increased risk of Alzheimer’s disease and cognitive decline, however, it remains unclear whether poor hygiene and gum disease lead to dementia. [1]

How do I improve my oral health?

It has been noted that establishing and maintaining good oral health habits throughout life is imperative. The damage of the P.gingivalis bacterium is done over a lifetime, not just in later life or after the onset of Alzheimer’s disease. Paying extra attention to your oral health can protect you, not only from Alzheimer’s disease, but from other health conditions including diabetes, coronary artery disease, heart attack, and stroke. Below you will find some basic oral health tips to improve or maintain your oral health! 

More research in this area?

Since the publishing of the initial research findings in January 2019, The GAIN Trial, a phase 2/3 trial sponsored by Cortexyme Inc, is just being put into motion. The trial began in April 2019, and is looking to treat more than 500 participants diagnosed with mild to moderate Alzheimer’s disease. Treatment with the study drug will last for one year. P.gingivalis levels will be measured in these participants before starting treatment, as well as, after treatment. Participants cognitive abilities will also be measured before, throughout, and after the study. More information about Cortexyme can be found here. The GAIN Trial website can be found here

[1] An Antimicrobial Approach to Treating Alzheimer’s? [Internet]. ALZFORUM. [cited 2019May14]. Available from: https://www.alzforum.org/news/research-news/antimicrobial-approach-treating-alzheimers
[2] Porphyromonas gingivalis in Alzheimer’s disease brains: Evidence for disease causation and treatment with small-molecule inhibitors [Internet]. Science Advances. Available from: https://advances.sciencemag.org/content/advances/5/1/eaau3333.full.pdf
[3] Cortexyme, Inc [Internet]. Cortexyme, Inc. [cited 2019May14]. Available from: https://www.cortexyme.com/
[4] GAIN Alzheimer’s Clinical Trial [Internet]. GAIN Study. [cited 2019May14]. Available from: https://gaintrial.com/
[5] Photo :Top 10 Dental Hygiene Tips [Internet]. Oswal Dental Clinic. 2016 [cited 2019May14]. Available from: http://www.oswaldentalclinic.com/top-10-dental-hygiene-tips/
[6] How KY, Song KP, Chan KG. Porphyromonas gingivalis: An Overview of Periodontopathic Pathogen below the Gum Line. Frontiers in Microbiology. 2016;7.