Pineal Gland Dysfunction in Alzheimer’s disease: Sleep distu
Alzheimer’s disease (AD) is a globally common neurodegenerative disease, which is accompanied by alterations to various lifestyle patterns, such as sleep disturbance. The pineal gland is the primary endocrine organ that secretes hormones, such as melatonin, and controls the circadian rhythms.

Melatonin has been reported to have multiple roles in the central nervous system, including improving neurogenesis and synaptic plasticity, suppressing neuroinflammation, enhancing memory function, and protecting against oxidative stress. Sleep disorders occur in 25–66% of AD patients. Several studies showed that sleep disturbance leads to cognitive decline, and increases the risk of AD by increasing Aβ burden.

Melatonin secreted from the pineal gland and extrapineal organs are important mediators of communication between pineal gland and the immune system in AD. Additionaly, pineal dysfunction in AD results in reduced melatonin production, which finally triggers sleep disturbance and poor sleep quality. Pineal dysfunction leads to the reduced hippocampal neurogenesis and hypothalamic neurogenesis.