Show 1159: Do Cold Sores Boost Your Risk for Dementia?

The past few months have produced some fascinating science stories from international sources. We interviewed two scientists in far-flung places to learn more about unexpected ways that microbes interact with us and affect our health. One researcher has developed some unique ways to study the microbiome of our digestive tract. Another is examining whether the herpes viruses that cause cold sores boost your risk of Alzheimer disease.

How Does Our Gut Microbiota Respond to Probiotics?

Dr. Eran Elinav works at the Weizmann Institute of Science in Israel. He has been studying the gut microbiota. Each of us carries a collection of microbes as unique as our fingerprints. Studying them isn’t easy: not all of the bacteria and viruses in our digestive tracts show up in stool. Dr. Elinav and his colleagues used colonoscopies to collect good samples directly from the large intestine. They also did an experiment to compare the effects of probiotics and placebo.

Surprisingly, they found that some proportion of people are resistant to any changes wrought by the probiotics. Others who take probiotics make room for the new species, at least temporarily. What could account for the differences? Dr. Elinav’s research group has also considered possible downsides from probiotics. One way that people often use probiotics, or “beneficial bacteria,” is to counteract the harm that antibiotics can do to our microbiota. How well do they work for that?

Do Cold Sores Boost Your Risk of Alzheimer Disease?

Dr. Ruth Itzhaki of the University of Manchester in England has been studying microbes that get into the brain, especially the virus that causes cold sores. Herpes simplex virus type 1 (HSV1) can travel along nerve cells and enter the brain. For years, Dr. Itzhaki has been collecting data suggesting that infection with HSV1 could contribute to the development of Alzheimer disease. A fascinating study from Taiwan suggests that people who take antiviral drugs to suppress HSV1 are much less prone to this form of dementia. Who might benefit from such medications?

This Week’s Guests:

Eran Elinav, MD, PhD, holds the Sir Marc & Lady Tania Feldmann Professorial Chair in Immunology at the Weizmann Institute of Science in Israel. Dr. Elinav is HHMI & the Bill and Melinda Gates Foundation International Research Scholar. He is also a Senior Fellow at the Canadian Institute For Advanced Research (CIFAR). The photo is of Dr. Elinav.

His website is: http://www.weizmann.ac.il/immunology/elinav
The research we discussed with him was published in Cell, Sep. 6, 2018. https://www.cell.com/cell/fulltext/S0092-8674(18)31102-4
https://www.cell.com/cell/fulltext/S0092-8674(18)31108-5

Ruth Itzhaki, PhD, is Professor Emeritus of Molecular Neurobiology at the University of Manchester and Honorary Senior Research Fellow at the University of Oxford.

You can find her publications in Neurotherapeutics, Jan. 2019 
and in Frontiers in Aging Neuroscience, Oct. 19, 2018.