Gum disease may trigger dementia: study

By Stephen Beech via SWNS

Gum disease could trigger dementia, suggests a new study.

American researchers have shown that the common oral health issue can lead to changes in brain cells called microglial cells, which are responsible for defending the brain from amyloid plaque.

The plaque is a type of protein that is associated with cell death, and cognitive decline in people with Alzheimer’s disease.

The new study, published in the Journal of Neuroinflammation, provides important insight into how oral bacteria makes its way to the brain.

Most adults have gum disease to some degree and most people experience it at least once.

The early stage of gum disease is known as gingivitis. If isn't treated, a condition can develop called periodontitis which affects more tissues that support teeth and hold them in place.

If periodontitis isn't treated, the bone in the jaw may be damaged and small spaces can open up between the gum and teeth. The teeth can become loose and may eventually fall out.

Although most people don’t associate oral disease with serious health problems, increasing evidence shows that oral bacteria play a significant role in diseases such as colon cancer and heart disease.

Now, new research by scientists at the Forsyth Institute with colleagues at Boston University shows a link between periodontal disease and the formation of amyloid plaque, a hallmark of Alzheimer’s.

Study senior author Dr. Alpdogan Kantarci, of the Forsyth Institute, said: “We knew from one of our previous studies that inflammation associated with gum disease activates an inflammatory response in the brain.

“In this study, we were asking the question, can oral bacteria cause a change in the brain cells?”

The microglial cells the research team studied are a type of white blood cell responsible for digesting amyloid plaque.

Forsyth scientists found that when exposed to oral bacteria the microglial cells became overstimulated and ate too much.

Dr. Kantarci said: “They basically became obese.

“They no longer could digest plaque formations.”

He says the finding is "significant" for showing the impact of gum disease on systemic health.

Gum disease causes lesions to develop between the gums and teeth. The area of the lesion is the size of a human palm.

Dr. Kantarci said: “It’s an open wound that allows the bacteria in your mouth to enter your bloodstream and circulate to other parts of your body."

He explained that the bacteria can pass through the blood/brain barrier and stimulate the microglial cells in the brain.

Using mouse oral bacteria to cause gum disease in lab mice, the research team were able to track periodontal disease progression in mice and confirm that the bacteria had traveled to the brain.

The team then isolated the brain microglial cells and exposed them to the oral bacteria.

The exposure stimulated the microglial cells, activated neuroinflammation and changed how microglial cells dealt with amyloid plaques.

Dr. Kantarci said: “Recognizing how oral bacteria causes neuroinflammation will help us to develop much more targeted strategies."

He added: “This study suggests that in order to prevent neuroinflammation and neurodegeneration, it will be critical to control the oral inflammation associated with periodontal disease.

"The mouth is part of the body and if you don’t take care of oral inflammation and infection, you cannot really prevent systemic diseases, like Alzheimer’s, in a reproducible way.”

The study was the first time that scientists caused periodontal disease with mouse-specific bacteria and could study the effects of same-species oral microbiome on the brain.

Dr. Kantarci said that having same-species bacteria and cells brings the test closer to replicating what the process looks like in humans.