Gut Microbiome and Alzheimer Disease

Intestinal bacteria may play a role in Alzheimer's disease. New research from Lund University, in Sweden, showed that intestinal bacteria can accelerate the development of Alzheimer's disease. According to the researchers, the results bring in new perspectives for the prevention and treatment of the disease. Our intestinal bacteria have a significant impact on how we feel about the interaction between our immune system, intestinal mucosa, and our diet. So, the composition of the gut microbiome is of great research interest in diseases such as Alzheimer's disease. The exact composition of our microbiome depends on what bacterial species we receive at birth, our genes, and our diet.

In a study with sick and healthy mice, the researchers found that mice with Alzheimer's disease had a different gut microbiome composition than healthy mice. The researchers also studied Alzheimer's disease in germ-free mice to further investigate the link between the intestinal microbiome and the disease. Mice without intestinal microbiome had significantly formed less beta-amyloid plaque in the brain. Beta-amyloid plaques are the aggregates that form in nerve fibers in cases of Alzheimer's disease.

In order to investigate if there is a link between the intestinal microbiome and the onset of the disease, the researchers transferred intestinal bacteria from mice with Alzheimer's disease to germ-free mice. The results showed that these mice developed more beta-amyloid plaques in the brain than the mice from the control group which had received bacteria from healthy mice.

This study is unique, as it shows a direct causal relationship between intestinal bacteria and Alzheimer's disease. It was striking that germ-free mice produced far fewer plaques in the brain. These results indicate that we can now begin the research on ways to prevent the disease and delay its onset.

The researchers continue to study the role of bacteria in the development of Alzheimer's disease and they try to investigate completely new types of prevention and treatment strategies based on the formation of the gut microbiome through diet or/and new types of probiotics.

Harach, T., Marungruang, N., Duthilleul, N., Cheatham, V., Mc Coy, K. D., Frisoni, G. et al., (2017). Reduction of Abeta amyloid pathology in APPPS1 transgenic mice in the absence of gut microbiota. Scientific Reports, 7. DOI: 10.1038 / srep41802