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Oral Bacteria Found in Alzheimer’s Tissue

Oral Bacteria Found in Alzheimer's TissueA particular type of oral bacteria has been linked to Alzheimer’s disease, according to a new study conducted by an international team of researchers.

They believe that the bacterium found in the brain can trigger immune system responses and pathological changes, which could lead to diseases such as Alzheimer’s.

For the study, Lakshmyya Kesavalu, an associate professor in the College of Dentistry at the University of Florida, and a team of international researchers examined the brain tissues of 10 Alzheimer’s patients and compared them with that of 10 non-Alzheimer’s brain samples.

A special type of test called immunofluorescence labeling and immunoblotting was used to screen the brains and find an oral bacterium called lipopolysaccharide.

Lipopolysaccharide, a component of Porphyromonas gingivalis, was found in four out of 10 Alzheimer’s disease brain samples. It was not found in any samples from the brains of people who did not have Alzheimer’s disease.

“This clearly shows that there is an association between oral bacteria and Alzheimer’s disease, but not causal association,” Kesavalu said.

The study is the first to show a link between the existence of the oral bacterium component lipopolysaccharide and Alzheimer’s disease.

The new research comes after a UF study conducted on mice that had been infected with four major periodontal pathogens. In that unpublished study, the researchers found that the oral bacterium moved to the brain in the mice, further confirming the group’s research on humans.

According to Kesavalu, the findings do not prove that oral bacteria causes Alzheimer’s disease, but preventing gum disease is still a good idea, and there are easy steps to take to do this.

“People should brush their teeth regularly twice a day. Second, they can floss their teeth regularly so there are no bacteria plaques between teeth, and third, they can visit their dentist for regular cleanings. Fourth, not smoking,” he said.

Kesavalu plans to continue this research.

“Having demonstrated oral bacterium components in Alzheimer’s disease brains, we are planning to study the causal association between major periodontal bacteria and Alzheimer’s disease in mouse models,” he said.

Gingivitis is found in 97 percent of the population, Kesavalu said. It is one of the most common diseases to affect humans, more common than the common cold.

Source:  Journal of Alzheimer’s Disease

Oral examination photo by shutterstock.

Oral Bacteria Found in Alzheimer’s Tissue

Traci Pedersen

Traci Pedersen is a professional writer with over a decade of experience. Her work consists of writing for both print and online publishers in a variety of genres including science chapter books, college and career articles, and elementary school curriculum.

APA Reference
Pedersen, T. (2018). Oral Bacteria Found in Alzheimer’s Tissue. Psych Central. Retrieved on November 25, 2020, from
Scientifically Reviewed
Last updated: 8 Aug 2018 (Originally: 5 Oct 2013)
Last reviewed: By a member of our scientific advisory board on 8 Aug 2018
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