Step Toward Potential
Treatment For 'Mad-Cow'-
Like Illnesses

NEW YORK - By identifying a compound that changes the nature of an infectious agent, researchers have taken a step toward treating spongiform encephalopathies, a group of fatal brain disorders that includes 'mad-cow' disease.
Although such diseases are rare in humans, identifying a treatment has become even more important since an outbreak of 'mad-cow' disease in cattle in Great Britain in the 1980s and early 1990s.
It is thought that a new type of Creutzfeldt-Jakob disease (CJD) " an incurable and rapidly fatal illness seen in a handful of young adults in the UK " may be linked to consuming meat from cattle with 'mad-cow' disease.
According to a report in the January 15th issue of The Lancet, researchers have discovered a peptide known as iPrP13 that interferes with the structure of the prion, the infectious agent thought to be the cause of spongiform encephalopathies. The prion accumulates in the brain, triggering biochemical changes that lead to dementia, an inability to talk or walk and ultimately, death.
Dr. Claudio Soto of New York University Medical Center and Serono Pharmaceutical Research Institute in Geneva, Switzerland, and colleagues extracted prions from the brains of mice and humans who had died of spongiform encephalopathy.
The investigators found that the iPrP13 peptide helped break down the prions in laboratory studies. When the peptide was added to the prions and both were injected into mice, the rodents tended to survive for a longer period of time before succumbing to the fatal disorder. The authors estimate that the peptide decreased the infectious nature of the prion by 90% to 95%.
The authors suggest that the findings may help to design treatments of infectious spongiform encephalopathies. The peptides "could represent prototype compounds for the development of new treatments that prevent or reverse... changes implicated in transmissible spongiform encephalopathies," the study concludes.
However, there are a number of problems with peptides that make them inadequate for treating human illness. The peptides tend to be degraded or attacked by the immune system before they reach their target, and it is very difficult to get them into the brain to interact with prions.
"There is still a lot of work to be done before we can use these peptides in the actual treatment of the disease," said Soto in a statement issued by The Lancet. "However, this concept may represent a novel approach for the rational design of drugs that may prevent protein conformational changes implicated in a variety of diseases."


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