The Gut Microbiome Might Influence Risk for Developing Alzheimer Disease

During the past 20 years, the collective genes of the microbes that live on and in our bodies, i.e., our microbiome, have been linked to an increasing number of diseases. The microbial genes produce proteins — including hormones, neurotransmitters, and molecules of inflammation — that affect human physiology. Different bacterial species are found in the guts of people with Alzheimer disease (AD) than in people without AD. But does AD change the gut microbiome, or does the gut microbiome influence risk for developing AD?

Investigators eliminated all bacteria from the guts of healthy young rats. Then they transplanted feces from a large group of AD patients, and feces from non-AD cognitively normal controls, into the rats' intestines. Transpla…