Longevity Briefs: Is Brain Shrinkage Always A Bad Thing?

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

A loss of brain volume is generally considered to be a bad thing, representing a loss of neurons that translates to a decline in cognitive function. Brain volume declines with age, but loss of brain volume is most drastic in the late stages of neurodegenerative diseases like Alzheimer’s. However, antibody treatments for Alzheimer’s, which are designed to clear amyloid plaque from the brain, also result in an excess loss of brain volume (not explained by the disease). Why does this happen, and is it a problem? A recent study investigates.

The discovery:

The researchers analysed data from existing clinical trials for amyloid-targeting antibodies and found that while these therapies were consistently associated with brain volume loss, there was no evidence that this loss of brain volume was harmful to patients. The extent of brain volume loss also correlated with how effective the therapy was at removing amyloid plaque. As a result, the researchers propose that removal of amyloid itself was responsible for the volume loss, which they term “amyloid-removal-related pseudo-atrophy”.

The implications:

A loss of brain volume being a benefit to health would be a first. It is interesting to think about whether there are any other situations in which brain atrophy might actually be harmless or even beneficial. Further clinical trials looking at this issue specifically will be needed to confirm these findings, but based on the available data, it looks like loss of brain volume in the context of these treatments is not a cause for concern.