UCSF prion finding in mice leads team to urge similar study...( University of California San Francisc...)

University of California, San Francisco researchers have made a finding regarding prions in mice that they say warrants similar study in cattle.

In their investigation, published in the March 19 issue of Proceedings of the National Academy of Sciences, the researchers report that mice exposed to the lethal prion (PREE-on) pathogen develop high levels of the infectious agent in some skeletal muscle. Until now, scientists have thought skeletal muscle was neither susceptible to high levels of infection, nor infectious. The researchers have not investigated whether high levels of prions amass in the skeletal muscle of cattle, sheep, deer or elk infected with prions.

Substantial evidence has suggested that prions only accumulate at high levels in brain, spinal cord and lymphatic tissue. As a result, Great Britain where the epidemic of the prion disease known as bovine spongiform encephalopathy (BSE)1. developed in cattle in the mid 1980s and countries of the European Union have banned brain, spinal cord and lymphatic tissues from the human food supply.2. This measure is the most extreme step these countries have taken in light of the considerable evidence that consumption of BSE-contaminated beef products causes a human form of the neurodegenerative disease, known as new variant Creutzfeldt-Jakob disease (nvCJD).

However, researchers have not reported whether the skeletal muscle of BSE-infected cattle transmits to mammals. And the UCSF researchers say that in light of their finding in mice this investigation should be carried out in both livestock and game.

Whether prions accumulate in the skeletal muscle of other animals remains to be established. But our findings indicate the need to carry out a comprehensive and systematic investigation of the distribution of prions in the skeletal muscle of animals who develop prion diseases, says the senior author of the study, Stanley B. Prusiner,3. MD, UCSF professor of neurology and biochemist
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Contact: Jennifer OBrien
jobrien@pubaff.ucsf.edu
415-476-2557
University of California - San Francisco
18-Mar-2002