Written by Karen Carlson, SIU School of Medicine
If you’ve ever had jet lag, you know how hard it can be to function until you’ve caught up on sleep.
A recently published study shows that long-term disruptions of the sleep/wake cycle causes chemical changes in the brain’s centers for learning and memory that may accelerate memory loss in Alzheimer’s disease. The study, published this month in the Journal of Alzheimer’s Disease, is a collaboration between the University of California-Irvine and SIU School of Medicine.
The study, performed at SIU School of Medicine and funded by the National Institutes of Health* and the SIU Center for Alzheimer’s Disease and Related Disorders (CADRD) provides the first evidence that altered circadian rhythms, similar to what might be experienced during jet-lag or shift work, accelerates memory problems in mice that develop Alzheimer’s-like symptoms.
The research team is a collaboration between the laboratories of Gregory Brewer, PhD, of the University of California-Irvine, and co-authors Shelley Tischkau, PhD, associate professor of pharmacology at SIU School of Medicine and Kelsey LeVault, a former SIU clinical research specialist. Brewer was a professor of Medical Microbiology, Immunology and Cell Biology at SIU School of Medicine for 34 years.
People with Alzheimer’s disease often experience changes in their sleep/wake habits and have trouble sleeping. The underlying cause of these disturbances has been unclear. The researchers tackled this question by changing the time of lights-on so that it occurred eight hours earlier than expected every three days for two weeks in a mouse model of Alzheimer’s disease (AD).
“What the study found was that it’s the timing of sleep is important,” Tischkau said. “Sleeping during the day is proving to be harmful to our body’s metabolism.”
The study design approximates what people would experience if they flew to Europe every three days. Jet-lagged animals in both groups of mice had decreases in overall activity and performed worse on memory tests compared to animals that did not experience changes in their light/dark cycles. The performance of the AD mice was, however, much worse than the jet-lagged normal mice. Follow-up studies indicated that the jet-lagged mice all had decreased levels of glutathione in the brain, and the AD mice were affected more than normal mice. Glutathione is an antioxidant that can protect brain cells from damage due to oxidative stress.
Glutathione deficiencies are associated with harmful changes in energy metabolism within brain cells, creating an environment of oxidative stress. Accelerated oxidative stress is known to contribute to memory loss in Alzheimer’s disease. Therefore, this study shows that circadian disruption decreases the ability of brain cells to protect themselves from oxidative stress. The study identifies these oxidative stress pathways as novel drug targets for treatment of Alzheimer’s disease.
When we turn back the clocks for daylight savings time, we experience how small changes in sleep/wake schedules affect our lives. The take home message for patients, clinicians and caregivers is that good sleep habits, particularly a regular sleep/wake schedule, help maintain good memory.
Copyright © SIU School of Medicine, Springfield, Illinois

http://www.j-alz.com/content/uci-study-finds-jet-lag-sleep-disruptions-spur-alzheimer’s-memory-learning-loss

*grant R01 AG032431