Her team conducted experiments by inducing strokes in both young and old mice. Remarkably 90% of the young mice recovered while nearly all the older mice died. Initially the researchers assumed this was due to larger strokes in older mice but surprisingly their strokes were actually smaller. Yet mortality remained high. Further analysis of blood samples revealed that the older mice had significantly higher levels of inflammation compared to the younger group.

In follow-up studies McCullough’s team discovered that bacteria had spread to the organs of the older mice leading to infections and sepsis common complications that often cause death in elderly stroke patients. When they sequenced these bacteria they found many originated from the gastrointestinal tract which houses the gut microbiome a vast community of microbes that help digest food and produce essential metabolites.

Under normal conditions the gut’s mucosal barrier and immune cells prevent these microbes from entering the bloodstream. However in the older mice stroke had damaged this protective barrier. The researchers also found that the gut bacteria in aged mice were different from those in young mice more pathogenic and harmful.

This led the team to transplant gut bacteria from young healthy mice into older mice after stroke. The results were striking: the older mice showed improved recovery and their survival rates significantly increased.

These and related findings have laid the groundwork for McCullough’s continued exploration of the microbiome’s crucial role in neurological health. Meanwhile other scientists have uncovered links between the gut and a wide range of conditions from depression to inflammatory bowel disease. This growing body of research is driving a shift in medicine toward innovative treatments and preventive strategies that consider the interconnected system known as the gut-brain axis.

Experts studying the gut-brain axis believe that although much remains to be discovered this area offers exciting potential for a science-backed holistic approach to treating and preventing disease one that acknowledges the complex relationship between the gut, brain, body, and mind.The bacteria and microorganisms that make up the microbiome play a vital role in maintaining overall health supporting key functions like digestion and immune system regulation. However when the balance of these gut microbes is disrupted a condition known as dysbiosis it can contribute to or worsen chronic illnesses especially those linked to inflammation. Dysbiosis can be triggered by factors such as diet antibiotic use or stress and may also be both a cause and a consequence of inflammation-related diseases.

Source: https://www.aamc.org/news/follow-your-gut-how-research-gut-brain-axis-could-unlock-new-therapies