The team studied mice both with and without Alzheimer’s and compared the composition of their intestinal bacteria. Those with the neurodegenerative disease had a different composition of gut bacteria compared to those without.
The team also examined mice with no gut bacteria who had Alzheimer’s and found that these mice had a much smaller presence of beta-amyloid plaque in the brain. This plaque forms lumps at the end of nerve fibers in those with Alzheimer’s, and the lower levels in relation to the lack of gut bacteria show a relationship between the two factors.
To further explore this connection, bacteria from diseased mice was transferred to mice without bacteria, and more plaque was developed as a result. In comparison, bacteria transferred from healthy mice to the mice with no bacteria had much less plaque growth. Frida Fak Hallenius was part of the research team and commented, “Our study is unique as it shows a direct causal link between gut bacteria and Alzheimer’s disease. It was striking that the mice which completely lacked bacteria developed much less plaque in the brain.”
The effect of gut bacteria on the progression of Alzheimer’s may open the door for new treatment and prevention methods through the manipulation of this bacteria. Hallenius commented, “The results mean that we can now begin researching ways to prevent the disease and delay the onset.” Further research is needed to understand whether these conclusions may be applied to humans, as well as what modifications would be necessary to slow and prevent the development of Alzheimer’s.
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