The research looked at 3,618 brains stored in the Mayo Clinic.
1,375 had confirmed Alzheimer’s and had died at different ages, providing a timeline of the disease’s progression.
Dr. Murray explained:
“Imagine looking at the rings of a tree — you can identify patterns, like the changing seasons and the aging of the tree, when viewing the tree’s cross-section.
Studying brains at different stages of Alzheimer’s gives us a perspective of the cognitive impact of a wide range of both amyloid and tau severity, and we were very fortunate to have the resource of the Mayo brain bank, in which thousands of people donated their postmortem brains, that have allowed us to understand the changes in tau and amyloid that occur over time.”
The researchers found that it was the tau protein, not amyloid, that predicted the onset of cognitive decline.
Dr. Murray explained the importance of the tau protein:
“Tau can be compared to railroad ties that stabilize a train track that brain cells use to transport food, messages and other vital cargo throughout neurons.
In Alzheimer’s, changes in the tau protein cause the tracks to become unstable in neurons of the hippocampus, the center of memory.
The abnormal tau builds up in neurons, which eventually leads to the death of these neurons.
Evidence suggests that abnormal tau then spreads from cell to cell, disseminating pathological tau in the brain’s cortex.
The cortex is the outer part of the brain that is involved in higher levels of thinking, planning, behavior and attention — mirroring later behavioral changes in Alzheimer’s patients.
Amyloid, on the other hand, starts accumulating in the outer parts of the cortex and then spreads down to the hippocampus and eventually to other areas.
Our study shows that the accumulation of amyloid has a strong relationship with a decline in cognition.
When you account for the severity of tau pathology, however, the relationship between amyloid and cognition disappears — which indicates tau is the driver of Alzheimer’s,”
The study is published in the journal Brain (Murray et al., 2015).
My wife is participating in several research programs at Mass. General Hospital/ Harvard Medical School. In one of the studies she had an MRI using a marker which identifies the Tau protein. In another they look at/measure the prescence of the amyloid plaque. She has had at least one MRI per year and one PET scan at Mass. General and they recently asked if she would donate her brain after her death. I told her she'd get into Harvard one way or another.
Ask if they want her eyes too? When my FIL died we did both which they were glad to get since they are researching spotting dementia via the eyes long before symptoms. It was to one of the research centers there in Boston.
Gawker, my DW participated in a Late Onset AD Genetic Study being conducted by Mayo and others, and donated her brain as well. The autopsy results confirmed the earlier diagnoses.
When my husband was diagnosed 7 years ago I asked his neurologist about it since she works at OHSU and participates in some of the studies. She gave me a number to call and was told they had all they needed. Wonder if it is any different now but then we live 4 hours away.