While beta-amyloid plaque is a common feature in the brains of older people with Alzheimer’s disease, the protein may start forming in the brains of people as young as 20.
Changiz Geula, PhD, of Northwestern University Feinberg School of Medicine, and colleagues examined brain cells known as basal forebrain cholinergic neurons, which are involved in memory. They are also are among the first brain cells to die as a result of both aging and Alzheimer’s disease.
The researchers examined these brain cells in three different groups of people who had died. Thirteen people were aged between 20 and 66 and had normal cognition upon their death. Sixteen people aged between 70 and 99 who did not have dementia when they died. And 21 people aged between 60 and 95 had Alzheimer's disease when they passed away.
Amyloid protein began to accumulate in these brain cells in young adulthood, the researchers reported in the journal Brain. In addition, they said that neurons in other regions of the brain did not have the same level of amyloid accumulation as in the basal forebrain cholinergic neurons.
“The lifelong accumulation of amyloid in these neurons likely contributes to the vulnerability of these cells to pathology in aging and loss in Alzheimer’s,” Geula said in a statement.
Faulty amyloid protein can form toxic clusters known as amyloid oligomers. The clusters were small in younger, healthier individuals, but larger in older people and those with Alzheimer’s, the researchers noted.
Understanding Alzheimer’s Disease
Alzheimer disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks, according to the National Institute on Aging. In most people with Alzheimer’s, symptoms first…
Brains of older people with Alzheimer’s disease show characteristic abnormal clusters of faulty protein called amyloid. Now, for the first time, scientists have discovered amyloid can begin to accumulate in the brains of people as young as 20. The finding is surprising because it was thought amyloid only began to accumulate later in life.
The researchers, from Northwestern University, Evanston, IL, report their findings in the journal Brain.
In their study, Prof. Changiz Geula and colleagues examined a specific group of brain cells known as basal forebrain cholinergic neurons. These brain cells are closely involved in memory and attention and are among the first to die in normal aging and in Alzheimer’s disease.