The University of Southampton study has revealed important new evidence about the hallmark protein build-up that takes place during Alzheimer’s.
The 2002, Phase 2, AN1792 (Elan) vaccine trial had to be halted as some participants developed serious side effects. The researchers have followed patients who were on the trial to find out exactly what effect the vaccine had on the brain.
The team found that the vaccine, while targeted at clearing the characteristic build-up of the amyloid protein from the brain, was also effective at dispersing the second key protein, tau, from nerve cell branches. It demonstrates for the first time in patients that the two proteins involved with Alzheimer’s disease are closely linked.
The team also revealed that the vaccine wasn’t effective at clearing the tau protein ‘tangles’ from the nerve cell body, only from the cell branches. It suggests this could be an important reason why the vaccine failed to help improve patients’ dementia and reveals it as a crucial treatment target.
Dr Delphine Boche, from the University of Southampton, said:
“The findings show that treatment aimed at amyloid may also modify tau changes in Alzheimer’s.
“The lack of change in tau in the bodies of nerve cells might explain why the people in the original AN1792 trial didn’t experience an improvement in cognitive functioning even though we saw amyloid clearance.
“This study demonstrates a link between these two Alzheimer’s-related proteins, which has been suspected but not clearly demonstrated in the human brain. The findings give us more basic information about the interaction between beta amyloid and tau in Alzheimer’s and may clarify how the disease progresses in the brain.”
Rebecca Wood, Chief Executive of the Alzheimer’s Research Trust, the UK’s leading dementia research charity, said:
“These are important findings and add to the evidence that the tau protein is a key target in our fight against Alzheimer’s disease. It’s crucial that we identify as many treatment targets as possible for this incredibly complex disease to increase the chances of swift progress.
“Research is the only answer to dementia, yet UK scientists remain the poor relations in comparison to other serious diseases. With the right level of support, our scientists can help avert the massive increase in numbers living with dementia forecast for the next generation.”