Regular sleep disruptions may not only make someone cranky the next day, it may be an underlying cause of learning and memory loss found in Alzheimer’s disease.
Gregory Brewer, PhD, of the University of California, Irvine, and colleagues subjected mice to circadian disturbances. They changed normal light-dark patterns with an eight hour shorter dark period every three days for young mice with Alzheimer’s and compared them to normal mice.
The jet lag the researchers created reduced activity in both groups of mice. However, in water maze tests, the Alzheimer’s mice had serious learning difficulties not seen in the normal mice, the researchers reported in the Journal of Alzheimer’s Disease.
Further examination of tissues found that the jet lag caused a decrease in the amount of glutathione, an antioxidant that prevents damage to parts of the cell, in the brain cells of all mice. However, the levels were far lower in the Alzheimer’s mice. Accelerated oxidative stress is an important part of Alzheimer’s-related learning and memory loss.
“The issue is whether poor sleep accelerates the development of Alzheimer's disease or vice versa,” Brewer said in a statement. “It's a chicken-or-egg dilemma, but our research points to disruption of sleep as the accelerator of memory loss.”
Understanding Alzheimer’s Disease
Alzheimer disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks, according to the National Institute on Aging. In most people with Alzheimer’s, symptoms first…
Chemical changes in brain cells caused by disturbances in the body’s day-night cycle may be a key underlying cause of the learning and memory loss associated with Alzheimer’s disease, according to a University of California, Irvine study.
The research on mice, led by UCI biomedical engineering professor Gregory Brewer, provides the first evidence that circadian rhythm-altering sleep disruptions similar to jet lag promote memory problems and chemical alterations in the brain.
Clinical application of this finding may lead to more emphasis on managing the sleep habits of people at risk for Alzheimer’s disease and those with mild cognitive impairment. Study results appear online in the Journal of Alzheimer’s Disease.