Yet more research[i] has just been published showing the bacterial microbiome’s connection to neurodegenerative diseases like Alzheimer’s and Parkinson’s. A variety of bacteria (including ones found in the mouth) produce amyloid proteins (known as bacterial amyloids) similar to the ones produced naturally by our neurons. (Remember, as I’ve described in a previous post, that amyloid proteins are thought to be a normal part of the immune system.) The amyloids produced by gut bacteria can change the structure of other proteins, thereby “…increasing the inflammation associated with neurodegeneration.”
E. coli, for example, produces amyloid proteins with “abnormal” configurations. In animal models, when E.coli produced these abnormal proteins, “…the animals’ own amyloid proteins also became abnormal – a process called cross-seeding.”
Since animals and humans all have some E.coli as a normal part of the biome, you do have to wonder why this abnormal cross-seeding only happens in some people. Researchers explain that the products of the gut bacteria can be protective or damaging, depending on their environment. Remember my post about H.pylori and immune tolerance?! Scientists explain that, “Cultural differences in human populations can also have profound influence on the microbiota…In fact, the geographical region where a person lives can influence the composition of the gut microbiota and, consequently, neurodegeneration.”
So diet, the depleted microbiome and macrobiome, maybe stress levels, lifestyle choices, etc. lay the stage for whether or not the bacterial amyloids have an adverse effect in us. I really wonder what the defining factor(s) will be? Levels of inflammatory cytokines or lack of regulatory ones? Low levels of particular bacterial species?