The risk of developing Alzheimer's disease doubles every five years after the age of 65. A new research has highlighted some key changes in the brain that causes Alzheimer's.
Researchers at the Washington University School of Medicine in St. Louis determined the changes associated with the amyloid beta 42 protein, which is the "primary driver" of Alzheimer's disease.
"We found that people in their 30s typically take about four hours to clear half the amyloid beta 42 from the brain. In this new study, we show that at over 80 years old, it takes more than 10 hours," said senior author Randall J. Bateman, Professor of Neurology.
According to the researchers, the slowdown in clearance rates results in rising levels of amyloid beta 42 in the brain, which increases the risk of protein clumping together to form Alzheimer's plaques.
The researchers tested 100 volunteers between the ages of 60 and 87, half of which had clinical signs of Alzheimer's disease and plaques had begun to form in the brains of 67 participants.
The study participants underwent mental and physical evaluations including brain scans and cerebrospinal fluid analyses. Stable isotope-linked kinetics (SILK) was used to evaluate the body's production and clearance of amyloid beta 42.
The researchers observed that in patients with signs of Alzheimer's plaques, amyloid beta 42 tended to be more lilely to fall from the brain fluid and clump together.
Reduced clearance rates of amyloid beta 42 was associated with clinical symptoms of Alzheimer's disease, such as memory loss and personality changes.
The researchers said that the key protein is disposed of in four ways " by moving it into the spine, pushing it across the blood-brain barrier, breaking it down or absorbing it with other proteins, or depositing it into plaques."
"Through additional studies like this, we're hoping to identify which of the first three channels for amyloid beta disposal are slowing down as the brain ages. That may help us in our efforts to develop new treatments," said Bateman.
The findings were reported in a recent edition of the journal Annals of Neurology.