Major US Prion Study
Begun - 175,000 BSE Cases
In England To Date
OMAHA, Neb. -- Proteins that may cause "mad cow" disease, chronic wasting disease in mule deer and elk, and Creutzfeldt Jakob disease in humans, all of which are fatal neurological diseases, are the subject of two studies at Creighton funded by federal grants.
Richard Bessen, assistant professor of medical microbiology and immunology, has received a five-year $488,000 National Institutes of Health grant and a three-year $250,000 grant from the United States Department of Agriculture to study prions.
Prions are proteins that all humans possess in their normal form. The disease forms are chemically identical but are configured in different shapes.
"What makes prions unique is that these infectious agents do not appear to contain a nucleic acid molecule which is the genetic basis of all life forms," Bessen said. "Prion diseases are caused by the misfolding of normal prion proteins. There is debate about how this misfolding occurs and how that pattern is replicated."
It appears that "mad cow" disease, or bovine spongiform encephalopathy (BSE), adapted from sheep scrapie.
"If you eat processed foods, such as sausage or products with animal-derived food additives, you may have been exposed to sheep scrapie, with no effect," Bessen said. "However, cattle apparently are susceptible upon oral exposure to scrapie-contaminated feed additives. Once they infected cattle, the prions may have adapted further to create an agent that posed danger to humans.
"The BSE epidemic in the United Kingdom indicates that these agents, transmissible spongiform encephalopathies or TSEs, can adapt unpredictably to new hosts and potentially can cause widespread neurodegenerative disease," Bessen said. "There have been more than 175,000 cases of BSE in Europe, mainly in the United Kingdom."
Initially, the potential danger of BSE to humans was downplayed, but BSE now has been linked to 27 cases of variant Creutzfeldt-Jakob disease in humans. The cattle industry has changed feeding and herd management approaches to avoid possible transmission of prion disease to humans and animals. No cases of BSE have been confirmed in the United States.
Bessen is examining the molecular basis of prion strain diversity and how prions replicate. He also will investigate the ability of drugs to inhibit the conversion of normal prions into the disease forms.
Creighton is an independent Catholic university operated by the Jesuits. It recently was ranked No. 1 for the third consecutive year among Midwestern universities in the U.S. News and World Report magazine's 1999 "America's Best Colleges" edition.
Creighton enrolls approximately 6,200 students in the Colleges of Arts and Sciences and Business Administration, the Graduate School, University College and schools of Nursing, Medicine, Law, Pharmacy and Allied Health Professions, Dentistry, and Summer Sessions.