New research into Alzheimer's disease may offer possible methods of preventing the degenerative brain disorder from developing.
The work suggests that neurons in the brain are killed off when blood vessels constrict due to the presence of highly reactive "free radical" molecules in the blood.
But the finding has also pointed up a weakness in Britain's science base. A key part of the research was carried out by Mike Mullan, a British scientist now working at the University of South Florida in the US. In 1991 he was one of a six-strong team based at St Mary's Hospital, London, who made a breakthrough by identifying a genetic link for Alzheimer's. However, that team has dissolved, with three of the scientists emigrating to the US and another to France. Only one of the original group is now left at the hospital.
The latest findings, published today in the scientific journal Nature, are based around the effects of an insoluble protein called -amyloid, which is found in the blood and particularly as deposits in the brains of people suffering from Alzheimer's.
-amyloid appears to react with cells in the walls of blood vessels in the brain to create "free radical" oxygen molecules. These are oxygen molecules that have lost an electron in a biochemical reaction and so are highly reactive. The free radicals appear to prompt the constriction of blood vessels which serve the neurons in the brain - leading, suggest the researchers, to the neurons' eventual dysfunction and death.
This leads them to suggest that Alzheimer's might be prevented - though not cured - by the provision of so-called "anti-oxidants", which are enzymes, and other chemicals which effectively neutralise free radicals by "mopping them up".
Other scientists gave a cautious welcome to the work. Jonathan Stamler, of Duke University Medical Centre in the US, said the work still had to be confirmed in humans: the latest work was only carried out on rats. He also queried the short timescale over which the free radicals affect blood vessels, compared with the decades over which Alzheimer's seems to take effect.
Simon Lovestone, of the Institute of Psychiatry in London, said "The idea that free radicals were a factor remained unproven for years. This is very interesting." Professor Mullan said yesterday: "The problem is to find an experimental means of testing our ideas fully. But it does open up new ways to deal with Alzheimer's."
He did not regret emigrating to the US. "After our work in 1991, the team was looking for more resources. The British offers might have meant we could have achieved the same, but it would have taken longer. I'm not sure it would have happened."
John Mulvey, of the pressure group Save British Science, commented that many researchers were put off by the facilities in Britain: The economy loses a competitive edge by not being able to keep its most promising talent, he said.
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