Brain’s Ability to Dispose of Key Alzheimer’s Protein Drops with Age

Researchers from Washington University School of Medicine in St. Louis have identified some of the key changes in the aging brain that lead to increasing the risk of developing Alzheimer’s disease. The changes center on amyloid beta 42, a main component of brain plaques that contribute to Alzheimer’s disease. The protein, a natural byproduct of brain activity, is typically cleared from the brain before it can clump together into plaques. “We found that people in their 30s typically take about four hours to clear half the amyloid beta 42 from the brain,” said the senior author of the study. “In this new study, we show that at over 80 years old, it takes more than 10 hours.” The slowdown in clearance results in rising levels of amyloid beta 42 in the brain. Higher levels of the protein increase the chances that it will clump together to form Alzheimer’s plaques. During the study, in patients with evidence of brain plaques, the researchers observed that amyloid beta 42 appears to be more likely to drop out of the fluid that bathes the brain and clump together into plaques. Reduced clearance rates of amyloid beta 42, such as those seen in older participants, were associated with clinical symptoms of Alzheimer’s disease, such as memory loss, dementia and personality changes. Scientists believe the brain disposes of amyloid beta 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, researchers are hoping to identify which of the four methods is the first to slow down as the brain ages. To read more about this study, click here.