2024 Alzheimer's Association Research Fellowship (AARF)

The impacts of postoperative delirium on AD progression

How might delirium after surgery contribute to Alzheimer’s progression?

Chengcheng Song, Ph.D.
Duke University
Durham, NC - United States

Background

With surgery there are certain risks that may occur, including  delirium, or the temporary disruption of mental abilities resulting in confusion and decreased awareness of one’s environment. Research has shown that individuals with Alzheimer's have an  increased risk for experiencing delirium after surgery which may accelerate cognitive decline. The precise reasons for this increased risk are unknown. 

The brain is protected by a specialized structure called the blood-brain barrier (BBB), which tightly regulates what is allowed to go into and out of the brain.Normal functioning of the BBB is essential to protect the brain from harmful changes. Studies show that in Alzheimer’s and other brain diseases, the BBB may become leaky and this may contribute to disease-related changes. Dr. Chengcheng Song and colleagues hypothesize that vascular (blood vessel) changes following surgery and disruption of the BBB may play a role in the increased incidence of delirium.

Research Plan

For their studies, Dr. Song and the team will perform orthopedic surgery on genetically engineered Alzheimer’s-like mice that develop amyloid plaques (one of the hallmark brain changes overserved in Alzheimer’s) and will assess BBB integrity after the procedure. They will measure changes in amyloid plaque levels following surgery to examine whether surgery promotes amyloid plaque build-up in the brain. Next, the researchers will perform behavioral and cognitive assessments on the same genetically engineered Alzheimer’s-like mice, as well as older cognitively unimpaired mice, that have undergone surgery.

Impact

Results of this study could improve our understanding of the mechanisms linking post-surgery delirium and Alzheimer’s progression. These findings may help inform care strategies for individuals with Alzheimer’s that undergo surgery.