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Circadian rhythms and aging . Julia Tong RE|NOUS March 03, 2014 General Meeting III . Outline. What is circadian rhythms (CR)? How does CR pertain to aging? How does CR affect AD? . Circadian Rhythms . Body go through cycles each day to maintain homeostasis.
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Circadian rhythms and aging Julia Tong RE|NOUS March 03, 2014 General Meeting III
Outline • What is circadian rhythms (CR)? • How does CR pertain to aging? • How does CR affect AD?
Circadian Rhythms • Body go through cycles each day to maintain homeostasis. • Every cell in your body has a rhythm (internal clock) and the output oscillates according to the environment. • Examples: • Blood pressure • Melatonin levels • Liver enzymes • Body temperature
Circadian Rhythms II • Think of bodily functions and secretions are clocks • SCN is the central clock • It is the site of the biological clock • Without it, the body is arrhythmic • Animal dies
SCN is critical to Circadian Rhythms Lehman et al. 1987
Circadian Rhythms and Aging • Aging changes the human circadian behavior • Older humans/animals circadian activity cycle shortens with age. • Think about your own circadian (sleep/wake) cycle! • Numerous studies have shown CR interconnected with longevity and age related changes in rhythms. • No clear mechanistic or molecular factors identified yet.
Looking at SIRT1 role in central circadian control of physiology and behavior
Paper’s Conclusion • SIRT1 regulate central circadian control to determine period, acitivty level, and adjust to reentrainment. • SIRT1 directly activates Bmal1 in SCN • Increasing expression of other clock genes • Aged mice have low SIRT1 and BMAL1 • Inability to adjust to abrupt light adaptation • Overexpressing brain SIRT1 are partially protected • Reversitol • Low fat diet
CR and Alzheimer’s Disease • AD pts. have disrupted CR • Sundowning: agitated during evening • Never get a complete night sleep, issues with sleep/wake cycle. • Sleep disturbances have devastating effects that leaves pts. Institutionalize. • Studies show that AD pts have disturbances in CR and sundowning is related to phase delay of body temperature
Slow aging with a good clock • Treat age related diseases by enhancing Circadian Function. • SIRT1 to brain • Other drugs along pathway • Treatment for AD patients, ease sundowning • Adjust patients to the Light/dark cycle • Understand patient’s CR • Sync them to environment • Bright light during morning • Melatonin at night