HOPE FOR A VACCINE TO PREVENT DEMENTIA

ANOTHER option is to vaccinate people against dementia — U.S. researchers are already testing a nasal vaccine on people with early Alzheimer’s disease.

The vaccine contains a compound, Protollin, that’s thought to mobilise the immune system’s white blood cells to ‘migrate to the brain and trigger clearance of beta-amyloid plaques’, the researchers from Brigham and Women’s Hospital in Boston in the U.S. said when they launched the trial this month.

The hope is that this could treat Alzheimer’s and prevent it in people at risk.

The University of Leicester is also testing a potential vaccine, albeit so far only in mice. They say they’ve discovered a version of amyloid-beta that specifically causes Alzheimer’s.

‘Trials so far have been targeting amyloid-beta plaque, but this is not a cause of disease but a consequence of it,’ says Mark Carr, a professor of biochemistry and chair of the Antibody-Assisted Drug Discovery Consortium at the university.

Using the analogy of measles, he explains that ‘to cure it you don’t treat the spots, you target the virus that causes disease — we identified a rare form of amyloid-beta that causes Alzheimer’s, and when we targeted it using an antibody in mice, we were able to spectacularly slow disease progression’.

The researchers identified that the type of amyloid-beta involved was hairpin shaped. ‘No one had ever suggested

amyloid-beta would form this type of structure — but this could explain why drugs so far haven’t been effective,’ says Professor Carr.

‘When we identified the structure, we were able to engineer an antibody [called TAP01 and given by injection] to target it.’

This is ‘a very different, interesting approach’, comments Robert Howard, a professor of old age psychiatry at University College London. ‘But it is still being studied in mice, so is a long way from fruition,’ he adds, sounding a note of caution.

‘From experience, we cure dementia in mice at least three times a week, but when we take it into human studies the results aren’t the same.’