A new method of treatment can appreciably slow down the progress of the fatal brain disease scrapie in mice. This has been established by researchers from the Universities of Munich and Bonn together with their colleagues at the Max Planck Institute in Martinsried. To do this they used an effect discovered by the US researchers Craig Mello and Andrew Fire, for which they were awarded this years Nobel Prize for Medicine. Scrapie is a variant of the cattle disease BSE and the human equivalent Creutzfeld-Jakob disease. However, it will take years for the method to be introduced to medicine, the researchers warn. Their findings are published in the next issue of the Journal of Clinical Investigation (Vol. 116, No. 12, December 2006).
Scrapie, Creutzfeld-Jakob and BSE are among the most unusual diseases known to medical research. Unusual because the pathogens are apparently neither viruses nor bacteria, being simply protein molecules known as protein prions. What is even more peculiar: exactly the same prion proteins occur in healthy animals. The only difference is that they have a different shape. When there is contact with their diseased twins they change their shape, also becoming diseased. The result is an irresistible chain reaction. The malformed prion proteins can be deposited in the brain, thereby destroying brain tissue. Prion diseases are always fatal, often, however, not until months after the outbreak of the disease. As yet there is no cure.
In mice suffering from scrapie the pathogenic prion protein is known as PrP-Scr, whereas the normal variant is PrP-C. PrP-C seems to have a protective effect in diseases like a stroke. Interestingly, mice which cannot produce any PrP-C appear to be completely healthy. This has become the starting point for a new therapeutic approach which for some years now has been current in research circles: can we not simply switch off the production of healthy PrP-C in infected animals, thereby depriving the d
Contact: Alexander Pfeifer
University of Bonn