Alzheimer’s disease is an extremely debilitating disease not only for sufferers, but for their family members as well. PET scans recently showed Tau deposition that can help track the progressive stages of Alzheimer’s in the brains of normal and healthy aging adults.
The study is being done by researchers at the University of California Berkeley, and they examined Tau deposition and retention patterns in 53 healthy adults. 5 were young adults (20-26), 33 were cognitively healthy adults (64-90), and 15 were adults aged 53-77 who had been diagnosed with dementia resulting from probable AD.
The researchers then measured Tau deposition by using the PET agent (18)F-AV-1451, which is a method created by German researchers through post mortem analysis of suspected AD patients.
The medial temporal lobe, which hosts the hippocampus and the memory center of the brain, is responsible for accumulating the tau protein, the microtubule protein important in maintaining the structure of neurons.
Tau is present in almost all aging brains, and for the study, every elderly person had tau. The team tested the participants episodic memory by asking them to recall a list of words they had viewed only twenty minutes earlier. Episodic memory is memory that regulates new information. Researchers found that higher levels of tau in the brain were linked to decline in episodic memory.
The research team wonders why some people with high levels of tau in their brain do not often develop Alzheimer’s later in life. Additionally, adults who may have beta-amyloid in their brains still end up being cognitively healthy.
A member of the research team, Samuel Lockhart, added that it does not mean that one protein is more vital than the other, and that “our study suggests that they may work together in the progression of Alzeimer’s.”
It may be that amyloid facilitates the spread of tau in the medial temporal lobe to other regions in the brain such as the neocortex. However, they have yet to discover how amyloid affects tau proteins and vice versa. All they know right now is that when the amyloid starts to show up, tau starts to show up in other parts of the brain, and that may be the beginning of symptomatic Alzheimer’s disease.
PET scans can be used as a tool for early diagnosis and staging, and can open up the possibility of developing therapeutic treatments that target the protein, largely depending on the stage of the disease.