A weak or misaligned circadian rhythm, can, over time, be causative of cognitive decline.
There is a daily oscillation in Aβ42 clearance and that this oscillation was lost in cells without a circadian rhythm.
Dissociation between the output of the circadian clock and external environmental cues is a major cause of human cognitive dysfunction.
A robust circadian clock regulates adult hippocampal neurogenesis.
Proper circadian protein function is important in the maintenance of neuronal integrity.
Circadian derangements/disturbed sleep feed the risk of developing AD.
Insufficient sleep can throw the circadian rhythm off, leading to potential cognitive problems.
Circadian dysfunction injures via altered gene expression.
In addition to being a key regulator of the diurnal cycle, the circadian clock might also suppress oxidative stress and synaptic damage. For example, a reduced level of BMAL1, one of the circadian regulating factors, is thought to cause neurodegeneration, as evidenced by the astrogliosis, oxidative damage, and synaptic damage in Bmal1 knockout mice.
In animal models of Alzheimer’s disease, a basal circadian rhythm that controls macroautophagy may be necessary to limit cognitive decline and amyloid deposition. Neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s disease may progress in the setting of altered circadian rhythm dysfunction.
Rats in which the circadian rhythm was messed up with continuous light for four months showed disrupted metabolic profiles, suggestive that their digestive systems may also have been adversely affected by the disrupted circadian rhythms. The level of soluble Aβ in the brain was also significantly higher in these rats compared to the controls, and they experienced down-regulation of anti-aging gene Sirt1 and up-regulation of the neuronal damage markers. Circadian rhythm disruption due to chronic light exposure caused memory and cognitive deficits in the rats. Collectively, these findings were suggestive of an AD-like phenotype.
“If your circadian clock is not quite right for years and years — you routinely suffer from disrupted sleep at night and napping during the day — the cumulative effect of chronic dysregulation could influence inflammatory pathways such that you accumulate more amyloid plaques”.
In patients with Alzheimer’s disease, rhythmic methylation of BMAL1 has been found to be changed in the brains of patients with Alzheimer’s disease, suggesting that alterations in the DNA methylation of clock genes may contribute to cognitive loss and behavior changes in individuals with Alzheimer’s disease
Other brain disorders are linked to a dysfunctional circadian system.
Minimizing blue light in the evening will maximize endogenous melatonin.
A robust circadian oscillation may minimize neuroinflammation