The hallmark characteristics of Alzheimer’s disease are buildups of amyloid and tau proteins, which damage neurons over time. But researchers have suspected that Alzheimer’s causes other, smaller changes to the brain, including some generated by the organ itself as it tries to fight the disease. These changes show up as different proteins, or the presence of new proteins altogether, but they’ve been incredibly hard to measure. Some scientists believe that if they could identify which proteins become more or less common in an Alzheimer’s-stricken brain, it could lead to future therapies.
A team of researchers based in England and New Zealand tried a new approach: They compared the brains of nine people who had died after suffering from Alzheimer’s disease to nine healthy brains from individuals who had died of heart disease, lung disease, or cancer. Each brain with Alzheimer’s pathology was age-matched to a healthy brain to rule out any differences due to routine aging. Doing so generated more than 24,000 different data points that show some of the changes in the brain that occur as a result of Alzheimer’s, making it the largest study of its kind to date.
The team compared protein levels in six different regions of the brain. Three of these regions—the hippocampus, entorhinal cortex, and cingulate gyrus—are often severely damaged by Alzheimer’s disease. Not surprisingly, in these regions the team observed major differences in proteins between brains with and without Alzheimer’s.
For a comparison, they also studied the motor cortex, sensory cortex, and cerebellum, which are suspected to show less wear and tear from Alzheimer’s. Sure enough, they found that proteins in these regions were fairly similar among brains with and without Alzheimer’s.
Except for the cerebellum. The scientists found that the proteins in the cerebellum, which sits on top of the brain stem and controls our movement and balance, were drastically different in Alzheimer’s-stricken brains and healthy brains. In a paper published this week in Communications Biology, the authors raise the possibility that “rather than being ‘spared’, the [cerebellum] is affected in a different way to other brain regions and that, given it shows little pathology, these changes may reflect some level of active protection.”
The team made all their data from this study freely available online in the hopes that innovative minds will use it to find potential new therapies for the disease.