LEXINGTON, Ky. — Two newly published studies from researchers at the University of Kentucky's Sanders-Brown Center on Aging are advancing understanding of how environmental factors and brain inflammation may influence sleep, circadian rhythms and Alzheimer's disease progression.

The research, led by neuroscience associate professor Adam Bachstetter, Ph.D., suggests that sleep disruptions in Alzheimer's disease may stem from both external environmental factors — such as nighttime light exposure — and inflammatory processes occurring in the brain itself.

In the first study, published in the journal SLEEP, researchers examined how dim light at night — similar to light from televisions, phones, hallway lighting and streetlights — affects circadian rhythms and Alzheimer's-related brain changes. The team found that nighttime light exposure disrupted daily activity rhythms and, in Alzheimer's disease models, modestly worsened amyloid buildup while altering immune cell activity toward a more inflammatory state.

"These studies examine why sleep and daily biological rhythms become disrupted in Alzheimer's disease, and whether those disruptions are influenced by both the outside environment and inflammation inside the brain," Bachstetter said. An accompanying editorial in SLEEP described artificial light at night as a potentially modifiable environmental factor that could influence Alzheimer's disease risk or progression.

The second study, published in Alzheimer's & Dementia, focused on what drives poor sleep once Alzheimer's pathology is already present. Researchers found that disrupted sleep and fragmented circadian rhythms emerged in midlife — before major memory deficits appeared. They then tested MW151, a compound developed by Sanders-Brown Director Linda Van Eldik, Ph.D., that targets excessive inflammatory signaling from glial cells in the brain.

Treatment with MW151 improved sleep patterns and restored more typical daily rhythms without reducing amyloid buildup. This finding suggests that inflammation — rather than amyloid alone — may be driving sleep disruption in Alzheimer's disease, according to the research.

"We now know that sleep can be improved without reducing amyloid," Bachstetter said. The Sanders-Brown Center on Aging is a nationally recognized leader in aging research and home to one of the world's premier brain banks dedicated to studying causes and treatments for Alzheimer's disease and related dementias.