Auriel Willette, Iowa State University – Alzheimer’s Disease and the Immune System

There’s a new area in the body to focus on in Alzheimer’s research.

Auriel Willette, assistant professor of food science and human nutrition at Iowa State University, says the immune system has a role to play beyond fighting off illnesses.

Dr. Willette’s laboratory examines the impact of obesity on the structure and function of the human brain. His main foci are metabolic dysfunction, such as insulin resistance, and chronic neuroinflammation. Archival and directly acquired primary data are used. Imaging techniques include volumetrics, FLAIR, DTI microstructure and tractography, MRS, task and resting state fMRI, ASL, FDG-PET, PiB-PET, AV45-PET. Non-imaging techniques include neuropsychological tests and questionnaires of cognition and affect/emotion, and body composition imaging, as well as ELISA, RIA, and mass spectrometry to associate biomarkers with neuroimaging and behavioral outcomes. Collaborations on animal models include diabetic dogs and rodents.

Alzheimer’s Disease and the Immune System

The immune system helps our body fight off illness…but it also plays a role in the debilitating memory loss associated with Alzheimer’s disease. As researchers, we’ve often focused on the damage or shrinking it causes in the medial temporal lobe – an area of the brain critical for creating conscious memories. But my colleague, Ashley Swanson, and I found we needed to pay more attention to other immune functions that help form memories and may defend against Alzheimer’s.

In our study, we examined memory performance and the medial temporal lobe over a two-year period for hundreds of older adults with no memory problems to those with moderate Alzheimer’s disease. We identified two proteins in the immune system that best predicted memory loss and shrinking in the medial temporal lobe.

One protein clears away debris outside of neurons and helps create stronger connections to relate more information. The second protein causes damage to neurons and shrinks the brain. Of the two, the one that helped build memories clearly stood out, while the damaging protein had little effect.

After two years, the memory-building protein explained nearly 30-percent of why some older adults had bigger or smaller medial temporal lobes. Most importantly, it could explain 56-percent of the difference between people with better or worse memory. Critically, more years of education were related to higher levels of the protein. This suggests that more time spent on learning and training your brain to process information will make your brain stronger. 

Our next steps are to understand how we can boost these protein levels. We are taking a comprehensive approach to see if diet, type of occupation, and even how people feel might affect the memory-building protein and our capacity to remember as we get older.