Alzheimer’s disease is the leading cause of dementia. It progressively worsens multiple aspects of health over time, from short-term memory loss to behavioral changes to loss of bodily functions. The actual cause of Alzheimer’s is currently unknown. One widely-accepted hypothesis proposes that Alzheimer’s is caused by the accumulation of misfolded proteins in the brain. Unfortunately, many drugs targeting misfolded proteins perform poorly in clinical trials, hinting that this hypothesis might be wrong. Misfolded proteins might be another side effect, not the cause.

Researchers recently published a new line of evidence supporting a hypothesis that Alzheimer’s might be a result of an infection by oral bacteria P. gingivalis. The bacteria produces toxins called gingipains that are found to accumulate in the brain of Alzheimer’s patients. The gingipains degrade human proteins, giving rise to the infamous misfolded proteins. The researchers also developed chemical compounds that could neutralize gingipains. Mice injected with gingipains developed degenerate brain cells, while mice that were pretreated with neutralizing compounds beforehand maintained healthy brain cells.

Although this new work might be the much-needed breakthrough in curing Alzheimer’s disease, the hypothesis is not conclusively proven and many questions still remain. Is P. gingivalis actually the cause of Alzheimer’s? Some experts still believe the disease could be caused by a fungal or viral infection. How does the bacteria get from the gum to the brain? What else does the gingipain toxin interact with in the brain? Are the neutralizing compounds safe or even effective in humans? 

Managing Correspondent: Veerasak (Jeep) Srisuknimit

Original Paper: Science Advance

Press article: Science, ScienceNews

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Image Credit: Modified from Pixabay

14 thoughts on “Oral bacteria may be responsible for Alzheimer’s disease

  1. My husband who has Alzheimers for the past 2 years was treated for gum disease 20 years ago. Do they think its a previous infection or a current infection. Are there any clinical trials expected?
    Thank you

  2. Are there any positive benefits from using drugs such as inbexa , donecept. And resperidone in the treatment of alzheimers

    1. Being so certain n relaxed that Alzheimer will never attack us is not fair,for that matter it can affect any one with aging,may be that in some people it comes as early as at 50 age n in some
      as late as 90 which is taken as normal regressive phenomena. The exact etiology n pathophysiology is not verified as till date but with due time it may be established with causes.

  3. Veerasak, I’ve been doing some research in herbs, and I might have found something promising. Any chance I could get your thoughts on the subject via email? Thank you for your time!

  4. I am very interested to see what comes of this study. I am a dental hygienist and have been wondering if there is a link for the past few years. I have had a few patients over the years diagnosed with Alzheimer’s/Dementia and I started to notice some of them with uncontrolled periodontal disease or what seemed to be more aggressive bacteria present. It’s hard to say if this was always present or lack of homecare due to the disease. It makes me want to keep closer watch on my patients and their health histories. I’m hopeful this is getting closer to a cure.

  5. An alzhemeir patient needs a care from a person. And also gives up his oral care. The person who takes care of him usually gets tire and can ignore the cleaning of teeth, so mouth. So giving up dental care results with an increasing amount of bacteria…

    1. True statement. Lots of patients who don’t use the arms have bad oral health due to people ignoring the oral care. Lots of patients who have dementia will not let you brush their teeth.

  6. Does the regular use of a mouthwash (e.g. Listerine) prevent these bacteria from settling in a person’s mouth?

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