Research: Lead-Associated Changes in Axonal Integrity in an Alzheimer's Disease Model
Awards: Westlake Science Fair 2021 Participant
Mentor: Dr. Kim
Research Location: New York Medical Center
Abstract:
Lead is a heavy metal that is found in small amounts in the earth’s crust. It is used in a variety of ways, and can be found throughout our environment, including in the air, water, and in our homes. Several studies have found that lead critically affects the body’s systems by hijacking the role of calcium in the body and brain. Lead can cause demyelination and increase stress on neurons, leading to neuronal death. Moreover, lead can cause heart disease, especially since it tends to take calcium’s role in blood vessel constriction, forcing the heart to pump blood through veins that are too narrow. Lead also tends to stay in the body for years, especially if absorbed by bones or astrocytes in the brain. Additionally, it has been found that lead exposure in developmental years can lead to Alzheimer’s disease (AD) later in life through changes in gene expression. In AD, two proteins, Abeta and tau, accumulate and cause damage to neuronal axons. Neuronal PC12 cells were cultured and exposed to lead. They were then allowed to cultivate over a period of 21 days. Myelination, axonal integrity, and microglial activation were observed every 7 days. Over the 21 day period, axonal integrity decreased, and the amount of myelinated axons decreased. After demyelination, axons have a reduced quality, abnormal neurofilament distribution, and an increase in microglia activation. Lead is detrimental to neurons, impairing axonal integrity and interfering with myelination.