Alzheimer’s and Gum Disease: Can One Bacterium Cause Both?
Gum problems affect more than half of the
world’s population, but most people choose to ignore their oral health -
a decision that can have dire consequences, as it turns out. An
increasing number of scientific findings point out how gum disease
causing bacteria can spread and affect the entire body, even your brain.
In a previous article, we’ve discussed how poor oral health can
contribute to heart disease and problems with episodic memory, but an
even more worrying finding has been made in 2019, suggesting that a
strain of bacteria that is typically involved in gum disease called
Porphyromonas gingivalis may be the cause of Alzheimer’s disease.
The Science Behind Alzheimer’s Disease
For decades, beta-amyloid plaques and TAU
tangles have been considered the cause of Alzheimer’s disease. These
plaques and tangles bunch together causing clumps in the brain tissue
that interfere with the function of our brain cells. As a result,
certain brain functions, such as short term memory, executive
functioning, and even emotional perception, just to name a few, become
affected, making Alzheimer’s sufferers progressively less and less
independent and capable of living life at its fullest.
An Illustration of Beta-Amyloid Plaques and TAU Tangles in the Brain Image Source: NIH Image Gallery/ Flickr
Indeed, beta-amyloid plaques and TAU
tangles are a unique and frequent finding in post-mortem studies in
Alzheimer’s patients, and for decades, the reason behind their
development was a mystery. One of the major hypotheses was that the
cause may be due to an infection, and once again, post-mortem research
suggested that it might be a strain of the herpes virus or even a fungus
that trigger the condition.
However, these studies were small, and their results too unconvincing
for the global medical community to recognize that infections cause the
neurodegenerative condition, especially since other factors, such as
genetics and age are known risk factors of Alzheimer’s.
The Link Between Gum Disease and Alzheimer’s
In 2019, a new study was published in the Science Advances journal
finding a bacterium typically associated with gum disease in the brains
of Alzheimer’s patients. But the researchers didn’t stop there and did a
follow-up study in an attempt to find not only a cause but also a cure
for the condition.
The scientists suggested that toxins called
gingipains produced by Porphyromonas gingivalis bacteria were to blame
for the creation of plaques and tangles, and they developed a drug they
called COR388 that blocks these gingipains. During this second
experiment, mice were exposed to the Porphyromonas gingivalis bacteria,
and after 6 weeks, the bacteria already appeared in their brain and
started causing plaques.
Then, the mice were treated with the drug the researchers had developed,
which resulted in a significant reduction of plaques in the mice’s
brains and halted neurodegeneration. The researchers conclude that
Alzheimer’s disease is caused by the Porphyromonas gingivalis bacterium,
and they are already in the process of conducting clinical trials on
human subjects to test the efficacy of the experimental drug.
In an interview with the New Scientist in December of 2019, one of the
leading authors of the study Steve Dominy revealed that 570 people with
mild to moderate Alzheimer’s from 95 health centers across the US and
Europe were enrolled in the clinical trial, and we should expect the
results in 2021.
A Critical View
While the gum disease study definitely
uncovered one way the beta-amyloid plaques and TAU tangles
characteristic of Alzheimer’s can occur, many leading scientists in the
field point out that we should look at the bigger picture instead of
stating that Porphyromonas gingivalis is the exclusive cause of
Alzheimer’s, as any other microorganism could likewise be responsible
for the formation of plaques and tangles.
Still, the research is exemplary, as it makes us reimagine what the
plaques and tangles found in Alzheimer's patients' brains really are - a
symptom of the disease, instead of its definitive cause. The study also
managed to show how an infection considered relatively harmless managed
to contribute to the development of the most widespread
neurodegenerative condition - Alzheimer’s disease.
The lesson here is clear: good overall health, including dental hygiene
and oral health, as well as a timely treatment of any infections, even
seemingly minor one, is key in preventing serious future health issues.