The Cause of Alzheimer's: Mouth Bacteria ?

[jedishrfu]

In recent years, a growing number of scientific studies have backed an alarming hypothesis: Alzheimer's disease isn't just a disease, it's an infection.

While the https://www.sciencealert.com/bacteria-could-be-the-key-to-understanding-and-treating-alzheimer-s of this infection are something researchers are still trying to isolate, a litany of papers argue the deadly spread of Alzheimer's goes way beyond what we used to think.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.

https://www.sciencealert.com/new-evidence-reveals-an-unexpected-culprit-behind-alzheimer-s-disease

 

[Ygggdrasil]

Here's a link to the study being discussed:

Dominy et al. Porphyromonas gingivalis in Alzheimer’s disease brains: Evidence for disease causation and treatment with small-molecule inhibitors. Sci Adv 5: eaau333 (2019)

Abstract:

Porphyromonas gingivalis, the keystone pathogen in chronic periodontitis, was identified in the brain of Alzheimer’s disease patients. Toxic proteases from the bacterium called gingipains were also identified in the brain of Alzheimer’s patients, and levels correlated with tau and ubiquitin pathology. Oral P. gingivalis infection in mice resulted in brain colonization and increased production of Aβ1–42, a component of amyloid plaques. Further, gingipains were neurotoxic in vivo and in vitro, exerting detrimental effects on tau, a protein needed for normal neuronal function. To block this neurotoxicity, we designed and synthesized small-molecule inhibitors targeting gingipains. Gingipain inhibition reduced the bacterial load of an established P. gingivalis brain infection, blocked Aβ1–42 production, reduced neuroinflammation, and rescued neurons in the hippocampus. These data suggest that gingipain inhibitors could be valuable for treating P. gingivalis brain colonization and neurodegeneration in Alzheimer’s disease.

http://advances.sciencemag.org/content/5/1/eaau3333

There's also evidence that other neurological diseases could be associated with or originate from bacterial infections, such as in Parkinson's disease:
https://www.theguardian.com/society...sease-could-originate-in-appendix-study-finds
http://stm.sciencemag.org/content/10/465/eaar5280

 

[BillTre]

Interesting.
Besides Alzheimer’s disease, periodontal disease has also been linked to heart valve issues and other heart problems.
However, this article says it may be due to a general inflammatory response rather than a direct infection of the valves by Porphyromonas gingivalis.