High level of Mn in brain is a risk for Alzheimer disease

Alzheimer disease (AD) is a neurodegenerative disease. Manganese (Mn) is an essential trace element in the human body. It can enter the brain through the blood-brain barrier and blood-cerebrospinal fluid barrier. Excessive accumulation of Mn in the brain may disturb the homeostasis of the central nervous system (CNS) microenvironment and cause severe neuronal damage. The most recent data suggest that excessive Mn is associated with impaired learning and memory in animal models, and may lead to irreversible and progressive mild cognitive impairment and AD. However, the mechanism for the involvement of Mn in AD pathogenesis remains controversial. This paper reviews the effects of Mn on CNS, mitochondrial function, p53 expression, and amyloid precursor protein/β-amyloid metabolism, and analyzes the relationship between these effects and AD pathogenesis.