The Connection Between Dementia and Infections

A new study from Harvard University suggests that beta amyloid protein may develop in the brain to fight off infections that have crossed the blood-brain barrier.The Connection Between Dementia and Infections

Learn more from this groundbreaking study about the connection between dementia and infections, and its implications on future studies.

How Symptomless Infections Can Lead to Dementia

A new study from Harvard University has found that silent, symptomless infections may lead to dementia. The study, published in the journal Science Translational Medicine, suggests that the production of beta amyloid protein (a hallmark characteristic of the disease), is the brain’s immune response to fight infections. When the infection enters the brain, passing through the blood-brain barrier, which breaks down with age, the brain will produce beta amyloid to capture the infection, leaving behind only the amyloid.

Researchers have tested the connection between dementia and infections in lab settings, using fruit flies, mice, petri dishes, roundworms and yeast. The study, led by Dr. Robert D. Moir and Dr. Rudolph E. Tanzi both of Harvard Medical School and Massachusetts General Hospital, began when the two researchers noticed the beta amyloid protein strongly resembled proteins of the immune system. In one study, researchers injected salmonella into the brains of mice with no beta amyloid plaques in the brain.

Dr. Tanzi said, “Overnight, the bacteria seeded plaques. The hippocampus was full of plaques, and each plaque had a single bacterium at its center.”

New Approaches to Beta Amyloid, Dementia and Infections

In the past, researchers have thought of beta amyloid proteins as waste that had gathered in the brain. Few researchers had thought there could be something else going on. A previous study linked the herpes virus to Alzheimer’s disease, but little other research backed up their findings, until now.

If infections in the brain are correlated to Alzheimer’s, then the herpes virus could be one of those infections wreaking havoc on brain health.

Drs. Tanzi and Moir acknowledge they have a strong hypotheses but are quick to say they have more work to do. Ultimately, researchers will look for microbes in the beta amyloid plaques found in human brains. Dr. Tanzi says that this “Is a big, big second step. First, we need to ask whether there are microbes that may sneak into the brain as we age and trigger amyloid deposition. Then, we can aim at stopping them.”

Did you know about the connection between dementia and infections? What are your thoughts on preventing the disease in this way? Share your suggestions with us in the comments below.

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  • Robyn Youlten

    Laboratory experiments on animals have NEVER proven ANYTHING conclusive in humans.WE have different metabolisms.

  • David burch

    My wife had a MRSA infection in her bloodstream. After heavy antibiotics she recovered but six months later she was diagnosed with AZ. I have always believed the MRSA triggered the AZ.

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