Medicine

Gum disease bug linked to Alzheimer’s (and new drug is being tested)

Gum disease bug linked to Alzheimer’s (and new drug is being tested)

The study, published Thursday in the journal Science, suggests that a lack of adequate sleep can advance Alzheimer's while good sleep could help maintain brain health.

In case you needed more reason to floss, scientists say a growing body of research indicates that Alzheimer's disease might be linked to Porphyromonas gingivalis, a strain of bacteria that's also known for causing chronic gum disease, New Scientist reports.

Researchers looked at brain tissue from autopsies of individuals with and without Alzheimer's disease and found a majority of those with the disease had higher levels of an enzyme called gingipains, which is produced by P. gingivalis.

Interestingly, the brains of 50 control bodies, who were elderly but did not suffer from Alzheimer's, contained low levels of gingipains.

"That is why we have created highly potent, brain penetrant, anti-gingipain small molecules to target P. gingivalis and gingipians in the brain", he said.

And in an experiment on mice, those dosed with gingipains had higher levels of the hallmark Alzheimer's protein, amyloid beta, and greater damage to their neurons than those who didn't.

Cortexyme has developed a drug that block gingipains and intends to run a larger trial later this year.

"Drugs targeting the bacteria's toxic proteins have so far only shown benefit in mice, yet with no new dementia treatments in over 15 years it's important that we test as many approaches as possible to tackle diseases like Alzheimer's", chief scientific officer David Reynolds from Alzheimer's Research commented in a statement.

In the study, Dominy and his colleagues swabbed P. gingivalis onto the gums of healthy mice every other day for 6 weeks.

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The improvements lasted for one week; future studies will focus on developing compounds that penetrate the brain more effectively and are thus longer-lasting. Some 10 percent experience a severe version of the disease, which erodes the gums and the bones that keep our teeth in place, the authors said.

"We will have to see the outcome of this ongoing trial before we know more about its potential as a treatment for Alzheimer's".

They tested the saliva and cerebrospinal fluid (CSF), which surrounds the brain and spinal cord, of people with Alzheimer's disease, looking for presence of P. gingivalis DNA.

"Not enough people are asking what is upstream of the plaques ... and [brain] inflammation", said Lynch, who has a background in Alzheimer's research and was frustrated by the string of failed therapies for the disease. "I'm much less convinced that [it] causes Alzheimer's disease", says neurobiologist Robert Moir of the Harvard University-affiliated Massachusetts General Hospital (MGH) in Boston, whose work suggests the β-amyloid protein that forms plaques in the brains of Alzheimer's patients is a protective response to microbial invaders.

The study adds to evidence of a link between gum disease and dementia, but it's still not clear if gum disease bacteria actually trigger Alzheimer's, said scientists not involved in the study, BBC News reported.

Risk Factors involved with the disease and that age is the greatest known risk factor for Alzheimer's, include an individuals risk for developing Alzheimer's increases after the age of 65, having a parent or sibling with the disease increases an individuals risk and 5.7 million people are now living with Alzheimer's.

In laboratory experiments, they found cell cultures infected with P. gingivalis showed signs of fractured or broken-up tau protein.

Many types of bacteria contributed to gum disease, but P. gingivalis was one of the most important. Inherited Alzheimer's is rare genetic disease.

"We found that in Alzheimer's disease, many subunits of glutamate receptors in the frontal cortex are downregulated, disrupting the excitatory signals, which impairs working memory", Yan said.