Memory loss is a common part of aging, but it varies greatly from person to person. Research shows that changes in the gut microbiome may play an important role in age-related cognitive decline. Certain gut bacteria, especially P. goldsteinii, increase with age and produce medium-chain fatty acids (MCFAs).
These bacterial products trigger inflammation in peripheral immune cells through a receptor called GPR84. The resulting inflammation disrupts signaling through the vagus nerve, reducing communication between the gut and the brain. Weakened gut–brain communication leads to reduced activity in the hippocampus, making it harder to form and store new memories.
The authors injected CCK–SAP and Blank-SAP (125 ng in 0.5 μl per ganglion) into the nodose ganglion of the vagus nerve to determine their role in cognitive decline.
The authors work suggests that in aged mice, memory could be improved by reducing P. goldsteinii, blocking GPR84 signaling, or restoring vagus nerve activity, suggesting new potential treatments for age-related memory loss.
