- guardian.co.uk, Wednesday 31 January 2007 15.11 GMT
A way of reversing brain impairment that strikes in the early stages of prion diseases such as vCJD and BSE has been identified by scientists.
The findings suggest there may be a way to cure vCJD, the human form of BSE, if it can be detected before it has time to kill off large numbers of brain cells.
The disease has so far claimed the lives of 158 people in Britain, and seven more are known to be infected. But many scientists believe that thousands more may be harbouring the disease but have yet to develop symptoms.
Prion diseases are caused when abnormal forms of natural proteins called prions get into the blood stream and force proteins already in the body to retract and suffocate brain cells.
Researchers led by Giovanna Malucci at the MRC prion unit at University College, London (UCL), used genetically modified mice to show that blocking the body's ability to make its own natural, healthy prions, reversed early symptoms of the disease.
They infected mice with abnormal prions and found they began to develop disease. But when the mice stopped producing their own prions, their symptoms cleared up.
"A psychologically healthy mouse will make nests and burrow, but they lose that early in the disease, they get withdrawn and depressed and lose their exploratory capacity," said Dr Malucci. "What we've shown is we can reverse that and get full functional recovery."
Major hurdles remain before the finding could be used as a cure. There is still no test that can detect vCJD infection before symptoms develop and no known drugs can switch off the production of healthy prions in humans.
"If there was a diagnostic test for humans that could pick the disease up early, hopefully there would be a potential for recovery with this treatment," Dr Malucci added. The study appears in the journal Neuron.
The UCL team is screening a vast array of drugs to identify if any can be used to stop prion production, but the next step in their research will investigate whether gene therapy can be used to switch off prion production in mice once they have developed prion disease.
This month, the government launched its first concerted effort to find out how common vCJD infection is in the general population by beginning vCJD tests on 100,000 pairs of tonsils gathered from operations around the country.
