September 13, 2012
Blood Test For Creutzfeldt-Jakob Disease and Mad Cow On The Horizon
April Flowers for redOrbit.com - Your Universe Online
Medical researchers from the University of Melbourne believe that a simple blood test for Creutzfeldt-Jakob Disease and Bovine Spongiform Encephalopathy, aka Mad Cow disease, is a step closer following a recent breakthrough.
Using newly available genetic sequencing, researchers have discovered cells infected with prions (the infectious protein responsible for these diseases) release particles which contain easily recognized signature genes.
Creutzfeldt-Jakob Disease and Bovine Spongiform Encephalopathy are not related to each other (although variant CJD is a form that is related to Mad Cow disease), however they share some similar traits that make this blood test effective for both.
CJD is a form of brain damage that leads to a rapid decrease of mental function and bodily movement, according to the U.S. National Library of Medicine. It is thought to be caused by a prion, which causes normal proteins to fold abnormally and affects their ability to function properly. CJD is very rare, around 1 in 1 million people have it, and symptoms usually start in the patient's late 50's. Variant CJD (vCJD) accounts for less than 1% of cases, and it tends to affect younger people.
Bovine Spongiform Encephalopathy, Mad Cow, is a fatal neurodegenerative disease in cattle that causes a spongy degeneration in the brain and spinal cord. All breeds of cattle are susceptible, and the heat of cooking the meat does not affect the infectious prion. Transmission seems to occur when healthy cattle are exposed to tainted tissues from infected cattle, for example meat and bone meal from cattle being added to feed. Mad Cow disease was linked to the deaths of nearly 200 people in Great Britain who consumed meat from the infected animals in the late 1980's.
Associate Professor Andrew Hill – from the Department of Biochemistry and Molecular Biology at the Bio21 Institute – said these particles travel in the blood stream, making a diagnostic blood test a possibility.
Since 2000, the Australian Red Cross Blood Service has not accepted blood from anybody who lived in the UK for more than six months between 1980 and 1996, or who received a blood transfusion in the UK after 1980. The American Food and Drug Administration (FDA) put an indefinite deferment period for blood donations on people who spent more than three months in the UK between 1980 and 1996, as of May 2002.
“This might provide a way to screen people who have spent time in the UK, who currently face restrictions on their ability to donate blood,” Hill said. “With a simple blood test nurses could deem a prospective donor´s blood as healthy, with the potential to significantly boost critical blood stocks.”
In the study, published in Nucleic Acids Research, Dr. Shayne Bellingham said the breakthrough might also help detect other human neurodegenerative disease such as Alzheimer's and Parkinson's.
“This is an exciting new field where we can test for conditions in the brain and throughout the body, without being invasive,” Bellingham said.
The researchers´ genetic testing focused on a form of cell discharge called exosomes. If exosomes were infected with prions they were found to also carry a specific signature of small genes called microRNA´s.