Copper/Prions

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Copper Influences Prion Disorders

April 29, 1999

NEW YORK (Reuters Health) -- The elements copper and zinc may prompt prions

-- the infectious proteins that cause " mad cow disease " and similar fatal

neurological diseases -- to change shape, leading to the generation of

different strains of prions.

The finding, from a study conducted by Dr. D.F. Wadsworth of the

Imperial College School of Medicine at St. 's in London, UK, and

colleagues, suggests that drugs that control copper levels in the brain might

be useful in treating prion disorders, such as Creutzfeldt-Jakob disease

(CJD), which currently have no known treatment or cure, according to the

report in the May issue of Nature Cell Biology.

Prion disorders -- including bovine spongiform encephalopathy, or " mad cow

disease " in cattle, CJD in humans, and scrapie in sheep -- are all

characterized by progressive neurological degeneration resulting in death.

These diseases are caused by a prion, an abnormal version of a

naturally-occurring protein, but researchers have recognized different

strains of prions that differ in incubation times, symptoms, and severity of

illness.

The researchers came to the conclusion by studying two different human prion

types that result in subtypes of CJD. There are four different types of CJD,

including a new variant that has appeared in young adults in recent years in

the UK and France, and is believed by some experts to be linked to

consumption of cattle infected with bovine spongiform encephalopathy.

Wadsworth's team studied types 1 and 2 of classical CJD -- rare disorders

that tend to strike in middle-age or later, causing dementia, muscle wasting,

and involuntary movements. Type 1 tends to be more aggressive and death often

occurs about 2 months after symptoms begin, while people with type 2 tend to

survive for about 8 months.

In laboratory studies, the researchers found that one prion type could be

converted into another in the presence of the copper or zinc ions.

The finding has " widespread implications " for both the classification and the

study of prion diseases in humans and animals, the authors conclude.

SOURCE: Nature Cell Biology 1999;1:55-59.