An unexpected connection found between intestinal problems and Alzheimer's disease

Scientists have found new evidence of a connection between gut health and the development of Alzheimer's disease. An international study led by specialists from the University of Wisconsin showed that people with signs of neurodegeneration have significantly higher levels of inflammation in the intestines, and this is directly related to the accumulation of pathological proteins in the brain. The work was published in the journal Scientific Reports.

As reported by BAKU.WS with reference to Scientific Reports, previous animal experiments had already indicated the role of the microbiome in transmitting signs of Alzheimer's disease to young mice. The new research clarifies the possible mechanism of this process - chronic inflammation in the intestines.

Scientists analyzed stool samples from 125 participants in two Alzheimer's disease prevention programs. They measured levels of calprotectin - a protein that serves as a marker of intestinal inflammation. In addition, participants underwent cognitive tests, questionnaires about family disease history, genetic analyses, and some of them underwent neuroimaging to detect amyloid plaques in the brain.

It was found that calprotectin levels increase with age, but they were especially high in people with amyloid plaques - a characteristic sign of Alzheimer's disease. At the same time, the increase in intestinal inflammation was accompanied by an increase in other biomarkers of the disease and a decrease in memory indicators. This connection was observed even in participants without a clinical diagnosis of dementia.

"We have shown that people with Alzheimer's disease have more pronounced inflammation in the intestines. And those who have higher inflammation accumulate more amyloid plaques in the brain," explained psychologist Barbara Bendlin from the University of Wisconsin.

According to one hypothesis, changes in the microbiome increase the permeability of the intestinal barrier. As a result, inflammatory molecules and toxins enter the bloodstream, which can disrupt brain protection, enhance neuroinflammation, and contribute to neuronal damage.

"Chronic, low-grade inflammation can accumulate damage imperceptibly for years and ultimately trigger neurodegenerative processes," noted bacteriologist Federico Rey, co-author of the study.

Scientists are currently continuing experiments on animal models, checking whether dietary changes that increase inflammation in the intestines can provoke the development of Alzheimer's disease analogs in mice.

Despite decades of research, effective treatment for Alzheimer's disease still does not exist. However, understanding the role of the gut and chronic inflammation brings scientists closer to a more holistic picture of the disease and potentially opens up new avenues for prevention and therapy.