New Research Sheds Light on Brain Inflammation and Alzheimer’s Disease

A team of researchers from Mayo Clinic’s Alzheimer’s Disease Research Center (ADRC) recently made an important discovery about what happens in the brain as Alzheimer's disease develops. In a study published in the journal Alzheimer’s and Dementia, investigators used a specialized type of brain scan to look at inflammation (the body's natural response to injury or disease) in the brains of 96 people at different stages of memory health.

Here's what they found:

• Inflammation shows up early. Even before people notice memory problems, signs of inflammation were already building in the brains of those on the path toward Alzheimer's disease.

• It spreads over time. As memory and thinking abilities declined, inflammation spread to more areas of the brain.

• Inflammation is closely tied to tau protein. Tau is one of the proteins that builds up in Alzheimer's disease. The researchers found that inflammation tracked most closely with tau, especially in brain areas that control memory and reasoning.

• Peak inflammation occurs in the early to middle stages of disease. People with only mild memory loss who were still able to function normally in their everyday lives (a stage of disease called mild cognitive impairment, MCI) showed the highest levels of inflammation, which then leveled off in later stages.

Why this matters:  This study tells us that the brain's immune system is actively involved in how Alzheimer's develops and spreads, and not just a side effect reacting to the disease. That opens the door to developing new treatments that could calm inflammation early, before serious memory loss sets in. The more we understand about how this disease works, the closer we get to better prevention and care for everyone.