A molecule made by bacteria in the human gut may raise the risk of Alzheimer's disease and hasten cognitive decline in people who already have dementia, according to research published in Nature Communications. The compound, imidazole propionate or ImP, is produced by certain intestinal bacteria, and the study's authors suggest it may contribute to the brain changes seen in Alzheimer's and related dementias.
The work builds on a line of research that began almost ten years ago at the University of Wisconsin-Madison, where professors Barbara Bendlin and Federico Rey found that the community of microorganisms living in the intestines looks different in people with Alzheimer's disease than in healthy people. That observation left an obvious question hanging: how could something happening in the gut change what happens in the brain? "Since then, we've been trying to figure out how this difference in the gut perhaps leads to changes in the brain," says Bendlin, a professor of medicine in the UW School of Medicine and Public Health.
Identifying a specific bacterial product, rather than a general shift in gut flora, is what makes this step interesting. A single molecule is something researchers can measure, track and potentially target. The team frames the finding as a possible route toward a treatment strategy aimed at lowering Alzheimer's risk, which would mean intervening somewhere in the body far from the brain itself.
That remains a goal rather than an achievement. The research describes an association and a plausible mechanism linking ImP to disease processes, not a therapy, and nothing in the work establishes that lowering ImP levels would protect anyone's memory.