Researchers find potential link between gum disease and Alzheimer's

October 4, 2013

(Medical Xpress)—Oral bacteria from poor dental hygiene have been linked to brain tissue degeneration, according to new evidence from an international team of researchers, including one at the University of Florida College of Dentistry.

UF's Lakshmyya Kesavalu, an associate professor in the College of Dentistry department of periodontology, and researchers from the University of Central Lancashire and The Blizzard Institute in the United Kingdom examined samples from the brains of patients with and without dementia.

Lipopolysaccharide, a component of Porphyromonas gingivalis, an oral bacterium, was found in four out of 10 Alzheimer's disease 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 and Alzheimer's disease, but not causal association," Kesavalu said.

Oral bacteria can enter the bloodstream during chewing, brushing and flossing, and during dental procedures. The bacteria, researchers believe, can enter through the bloodstream to the brain and can potentially lead to degeneration in that appears similar to Alzheimer's disease.

The research, led by senior author StJohn Crean, dean of the College of Medicine and Dentistry at the University of Central Lancashire, is the first study to show a link between the existence of the oral bacterium component lipopolysaccharide and Alzheimer's disease. The paper was published in July in the Journal of Alzheimer's Disease.

The study follows work at UF on mice infected with four major periodontal pathogens. In that unpublished study, the researchers found the oral bacterium moved to the brain in the mice as well, further confirming the group's research on humans.

Gingivitis is seen 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. According to the Centers for Disease Control and Prevention, about 64 percent of seniors age 65 and over have moderate or severe periodontal disease. Alzheimer's disease, according to the Alzheimer's Association, is the sixth leading cause of death in the United States—affecting more than 5 million Americans.

The brain disease costs the U.S. both money and lives. One in three senior citizens dies from Alzheimer's or another form of dementia. In 2013 Alzheimer's is projected to cost the country $203 billion, according to the Alzheimer's Association.

"Right now, globally about 36 million people are affected by Alzheimer's disease (according to the World Health Organization) and it may go up to 115 million by 2050," Kesavalu said.

According to the study, researchers think the bacterium found in the brain can trigger immune system responses and pathological changes, which may lead to diseases such as Alzheimer's. Researchers studied the brain tissue of 10 Alzheimer's patients and compared it 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 lipopolysaccharide.

Although the findings do not prove that causes Alzheimer's disease, preventing gum disease is still a good idea, and there are easy steps to take to do this, Kesavalu said.

"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.

So what's next in Kesavalu's 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.

Explore further: New Alzheimer's research suggests possible cause: The interaction of proteins in the brain

Related Stories

New Alzheimer's research suggests possible cause: The interaction of proteins in the brain

June 19, 2013
For years, Alzheimer's researchers have focused on two proteins that accumulate in the brains of people with Alzheimer's and may contribute to the disease: plaques made up of the protein amyloid-beta, and tangles of another ...

What goes wrong in a brain affected by Alzheimer's disease?

August 22, 2013
The ability of different regions of the brain to communicate gradually breaks down with aging and in Alzheimer's disease, but there are key differences between these two processes. Some of these differences are reported in ...

Fluorescent compounds allow clinicians to visualize Alzheimer's disease as it progresses

September 18, 2013
What if doctors could visualize all of the processes that take place in the brain during the development and progression of Alzheimer's disease? Such a window would provide a powerful aid for diagnosing the condition, monitoring ...

New hope for dementia sufferers

February 8, 2013
(Medical Xpress)—Research that aims to rid dementia sufferers' brains of toxins could lead to a new treatment that reverses the symptoms of Alzheimer's disease in the future.

Key cellular auto-cleaning mechanism mediates the formation of plaques in Alzheimer's brain

October 3, 2013
Autophagy, a key cellular auto-cleaning mechanism, mediates the formation of amyloid beta plaques, one of the hallmarks of Alzheimer's disease. It might be a potential drug target for the treatment of the disease, concludes ...

Alzheimer's patients show striking individual differences in molecular basis of disease

September 12, 2013
Alzheimer's disease is thought to be caused by the buildup of abnormal, thread-like protein deposits in the brain, but little is known about the molecular structures of these so-called beta-amyloid fibrils. A study published ...

Recommended for you

Lifestyle changes to stave off Alzheimer's? Hints, no proof

July 20, 2017
There are no proven ways to stave off Alzheimer's, but a new report raises the prospect that avoiding nine key risks starting in childhood just might delay or even prevent about a third of dementia cases around the world.

Steering an enzyme's 'scissors' shows potential for stopping Alzheimer's disease

July 19, 2017
The old real estate adage about "location, location, location" might also apply to the biochemical genesis of Alzheimer's disease, according to new research from the University of British Columbia.

Brain scans may change care for some people with memory loss

July 19, 2017
Does it really take an expensive brain scan to diagnose Alzheimer's? Not everybody needs one but new research suggests that for a surprising number of patients whose memory problems are hard to pin down, PET scans may lead ...

Can poor sleep boost odds for Alzheimer's?

July 18, 2017
(HealthDay)— Breathing problems during sleep may signal an increased risk for Alzheimer's disease, a trio of studies suggests.

Hearing is believing: Speech may be a clue to mental decline

July 17, 2017
Your speech may, um, help reveal if you're uh ... developing thinking problems. More pauses, filler words and other verbal changes might be an early sign of mental decline, which can lead to Alzheimer's disease, a study suggests.

Bacteria found in Alzheimer's brains

July 17, 2017
Researchers in the UK have used DNA sequencing to examine bacteria in post-mortem brains from patients with Alzheimer's disease. Their findings suggest increased bacterial populations and different proportions of specific ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.