"Infectious agents have been implicated in the development and progression of Alzheimer's disease before, but the evidence of causation hasn't been convincing", said Stephen Dominy, M.D., Cortexyme co-founder and lead author on the paper.
Scientists from Cortexyme, Inc., a privately held, clinical-stage pharmaceutical company, analyzed the brain tissues of patients with Alzheimer's disease and found evidence of Porphyromonas gingivalis, the bacteria associated with gum disease.
Now, scientists are saying they've got one of the most definitive leads yet for a bacterial culprit behind Alzheimer's, and it comes from a somewhat unexpected quarter: gum disease.
People with Alzheimer's are more susceptible to getting infections in their brains, so it may be that the gum disease bacteria and the toxic proteins they secrete are a by-product of Alzheimer's rather than a cause.
In the study, "Neuropsychological Deficit Profiles, Vascular Risk Factors, and Neuropathological Findings in Hispanic Older Adults with Autopsy-Confirmed Alzheimer's Disease" in the Journal of Alzheimer's Disease, autopsies of 14 Hispanic and 20 non-Hispanic persons were reviewed, all with autopsy-confirmed physiological evidence of AD.
And, in follow-up studies in mice, researchers at Washington University School of Medicine in St. Louis showed sleeplessness accelerates the spread through the brain of toxic clumps of tau.
Following on from their findings, the team also tested blocking the bacteria in mice by injecting small molecules targeting Pg, to inhibit it, and found that it could reduce neurodegeneration in the brain, showing a potential new way to tackle Alzheimer's disease. The treatment recently passed human safety studies and is due to enter Phase II/III clinical trials in mild to moderate Alzheimer's patients this year.
The authors of the new study published in Science Advances propose that Alzheimer's develops when gingipains accumulate fast enough to cause a patient to show symptoms. This time, experimenting on mice, the researchers found: caused by bacteria infection correlated with an increase in brain beta-amyloid protein whose accumulation is associated with damage to neurons in the brain and development of Alzheimer's disease. Jerrah Holth and colleagues studied tau levels in the brain ISF of mice as their sleep patterns were disrupted.
Edelmayer also cautions not to put too much weight on drugs tested in mice. "With individuals, we want people to know that the association really does a lot as far as education, support groups, health line and many other ways to help those in need". The researchers attribute this loss to an "elevation" of proteins responsible for suppressing glutamate receptor maintenance, otherwise known as repressive histone modifiers.
AD results from both genetic and environmental risk factors, such as ageing, which combine to result in epigenetic changes, leading to gene expression changes, but little is known about how that occurs.
The researchers hope this will provide the basis for developing a new therapy that could one day treat humans in a similar way.
One way to do that is to attend a Dementia Friendly training event like the one I will be hosting in conjunction with the Alzheimer's Society at the Age UK Roundhouse in Ashington on Friday, February 8, at 11.30am.