- A disease similar to the fatal human illness CJD can
be prevented and reversed in mice, scientists say.
-
- All CJD-like illnesses occur when normal nerve cell proteins
- prions - convert into an abnormal form, causing dementia and death.
-
- Mutant mice that lacked normal prions did not get sick,
researchers found, even if abnormal prions were present.
-
- This suggests that the disease is caused by the conversion
process - not the abnormal prions.
-
- The findings are published in the journal, Science.
-
- Crippling illness
-
- When a prion becomes abnormal or 'rogue', scientists
believe it changes all the surrounding prions into an abnormal form as
well.
-
- The result of this process is a crippling disease which,
in humans, causes a slow descent into a vegetative state and, ultimately,
death.
-
- It has been the natural assumption that these symptoms
are due to the build up of abnormal prions. It was thought something about
them - their odd shape perhaps - caused the brain to degenerate.
-
- For this reason, most research has focused on finding
ways to prevent the accumulation of abnormal prions in nerve tissue.
-
- But, when tried out on laboratory animals, these therapies
were disappointing.
-
- Now researchers, led by John Collinge and Giovanna Mallucci
of the MRC prion unit, University College London, believe previous experiments
focused on the wrong step of the process.
-
- Prion conversion
-
- The researchers bred a strain of mutant mice which, after
12 weeks of age, lost their normal prions.
-
- When these mice and ordinary mice were both infected
with abnormal prions they all began to develop a CJD-like disease.
-
- But after 12 weeks, when the mutant mice lost their normal
prions, the disease reversed - but continued to progress in the ordinary
mice. Although abnormal prions carried on building up in their brains,
the mutant mice remained healthy, whereas the control mice all died within
two weeks.
-
- These results suggest that abnormal prions themselves
are not the problem - the problem is something to do with the conversion
process between a normal prion and an abnormal prion.
-
- Dr Mallucci and her colleagues conclude that there is
a toxic intermediate stage that is the ultimate cause of CJD-like illnesses.
-
- "The conversion process might produce a toxic intermediate
stage, or it might somehow cause the nerve tissue to break down - but at
the moment we just don't know," Dr Mallucci told BBC News Online.
-
- They suggest that, in the future, CJD might be treated
by therapies that target normal prions within the brain.
-
- Dr Mallucci said: "A therapeutic strategy could
involve developing a drug that binds to normal prions, causing their depletion."
-
- © BBC MMIII
-
- http://news.bbc.co.uk/1/hi/sci/tech/3228549.stm
-
-
- Comment
From Pam Rotella
11-1-3
-
- This info fits with Purdey's theory. According to Purdey
& Brown, the holes in the brain are caused by periods of high oxidation
when normal copper-tipped prions switch to manganese-tipped. But prions
are involved in protecting sensitive tissues from UV radiation, especially
in the eyes. If they come up with a drug to just destroy all prions, I'm
sure blindness & skin cancer would be a side effect. Leave it to modern
medicine to recommend a drug to just destroy prions, instead of dealing
with environmental factors (some of which are their own/organophosphates
as chelating agents) that cause the prions to mutate in the first place...
|
