Animal study suggests inadequate sleep may exacerbate cellular aging in the elderlyJune 30, 2008Cellular response to sleep deprivation is impaired in old mice PHILADELPHIA - Researchers at the University of Pennsylvania School of Medicine have shown that the unfolded protein response, which is a reaction to stress induced by sleep deprivation, is impaired in the brains of old mice. The findings suggest that inadequate sleep in the elderly, who normally experience sleep disturbances, could exacerbate an already-impaired protective response to protein misfolding that happens in aging cells. "Protein misfolding and aggregation is associated with many diseases like Alzheimer's and Parkinson's," notes first author Nirinjini Naidoo, PhD, Assistant Professor in the Division of Sleep Medicine. The study appears in the June issue of the Journal of Neuroscience. The unfolded protein response (UPR) is one part of the quality control system for monitoring protein synthesis in the endoplasmic reticulum, the cellular compartment where some proteins are made. In this study, researchers found that the UPR was activated in 10-week old, sleep-deprived mice, so that misfolded proteins did not accumulate in the endoplasmic reticulum of brain cells in the cerebral cortex. However, in two-year-old, sleep-deprived mice, the UPR failed to do its job and misfolded proteins clogged the endoplasmic reticulum. Old mice that were not stressed by sleep deprivation were shown to already have an impaired UPR. Sleep in mice is characterized by short periods of inactivity throughout the day and night. On average, mice sleep approximately one hour for every two they are awake. In order to deprive mice of sleep, researchers constantly monitored and gently stroked the mice with a brush to disturb periods of inactivity. At 3, 6, 9, or 12 hours of sleep deprivation, proteins were examined from the mouse brains. By six hours of sleep deprivation, young mice demonstrated that the UPR system was in place because protein synthesis was shut off by a chaperone protein called BiP/GRP78. In contrast, there was no BiP/GRP78 in old mice so protein synthesis continued. Old mice also had less of the proteins that refold abnormal proteins than young mice, and old mice had more of the proteins that cause cell death than young mice. Thus, several processes are upset in old mouse brains by sleep deprivation, and the overall result is a further accumulation of misfolded proteins. "We could speculate that sleep disturbance in older humans places an additional burden on an already-stressed protein folding and degradation system," says Naidoo. Future studies will examine whether augmenting key protective proteins delays the effects of aging and reduces sleep disturbances. University of Pennsylvania School of Medicine |
|||||||||||||||||||||
| Related Sleep Deprivation Current Events and Sleep Deprivation News Articles Study shows that sleep deprivation can negatively affect information processing A study in the Nov.1 issue of the journal Sleep shows that sleep deprivation causes some people to shift from a more automatic, implicit process of information categorization (information-integration) to a more controlled, explicit process (rule-based). Fighting Sleep, Penn Researchers Reverse the Cognitive Impairment Caused By Sleep Deprivation A research collaboration led by biologists and neuroscientists at the University of Pennsylvania has found a molecular pathway in the brain that is the cause of cognitive impairment due to sleep deprivation. First human gene implicated in regulating length of human sleep Scientists have discovered the first gene involved in regulating the optimal length of human sleep, offering a window into a key aspect of slumber, an enigmatic phenomenon that is critical to human physical and mental health. Dementia induced and blocked in Parkinson's fly model Parkinson's disease is well-known for impairing movement and causing tremors, but many patients also develop other serious problems, including sleep disturbances and significant losses in cognitive function known as dementia. Lack of sleep could be more dangerous for women than men Women who get less than the recommended eight hours sleep a night are at higher risk of heart disease and heart-related problems than men with the same sleeping patterns. Sleep duration is associated with variations in levels of inflammatory markers in women A study in the July 1 issue of the journal SLEEP demonstrates that levels of inflammatory markers varied significantly with self-reported sleep duration in women but not men. Poor sleep is independently associated with depression in postpartum women A study in the July 1 issue of the journal SLEEP suggests that postpartum depression may aggravate an already impaired sleep quality, as experiencing difficulties with sleep is a symptom of depression. Gene predicts how brain responds to fatigue, human study shows New imaging research in the June 24 issue of The Journal of Neuroscience helps explain why sleep deprivation affects some people more than others. Caffeine intake prevents risk taking after extreme sleep deprivation Caffeine use prevents increased risk taking that occurs after several nights of total sleep deprivation. Older adults less affected by sleep deprivation than younger adults during cognitive performance Older adults are able to retain better cognitive functioning during sleep deprivation than young adults. More Sleep Deprivation Current Events and Sleep Deprivation News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||