Easier diagnosis of Creutzfeldt-Jakob disease discovered
Ortenberg, August 2014 - For the first time, a non-invasive and easy-to-perform test allows early diagnosis of the fatal neurodegenerative Creutzfeldt-Jakob disease (CJD) on living patients. Until now, a clear diagnosis in living patients was still a major challenge as the presence of the responsible pathogenic, the prion protein, could only be detected after a brain biopsy or autopsy.
A new, non-invasive procedure, based on the analysis of samples obtained from patient nasal brushings, proves to be an accurate and reliable diagnose of Creutzfeldt-Jakob disease. Researchers from Byron Caughey’s group at Rocky Mountain Laboratories, Hamilton, USA previously developed a test for the detection of prion proteins, the Real-Time Quaking-Induced Conversion (RT-QuIC), on BMG LABTECH’s FLUOstar® Omega microplate reader. The FLUOstar® Omega meets the requirements of RT-QuIC seeding assays as the reader is very robust and the transport system can handle harsh settings, such as long periods of high-speed shaking. The development of a prion detection test that could be measured on a microplate reader increased throughput and decreased detection time.
Still, this test could be only applied to samples obtained from brain biopsies. In cooperation with the laboratory of Gianluigi Zanusso at the University of Verona, Italy the RT-QuIC test has been applied on samples collected from brushings of the olfactory epithelium, a far less invasive procedure that can also be applied to living patients. The test on nasal brushings had a sensitivity of 97% and tested positive in 30/31 patients with CJD and negative in all (43/43) healthy patients.
This as yet experimental assay was published in the New England Journal of Medicine, the most prestigious journal of medical research. The developed assay consists of the introduction of a swab into the nasal cavity, under the guidance of a fiberscope. The procedure is totally harmless, and can be repeated several times with no danger for the patient. This work opens important perspectives for the diagnosis of neurodegenerative diseases that was so far only possible by autopsy. Moreover, it offers new strategies to identify early markers in the olfactory tissue with potential implications in serious neurodegenerative diseases.
Spongiform encephalopathies or "prion diseases" are a group of fatal neurodegenerative diseases that affect humans and animals. Creutzfeldt-Jakob prion disease is notorious for its transmission to humans following consumption of cattle meat infected with Bovine Spongiform Encephalopathy (mad cow disease). The pathogen is a modified (misfolded) prion protein that is able to modify “healthy” prion proteins and promotes their extracellular aggregation within the central nervous system. These aggregates form plaques which disrupt the normal nervous tissue structure and lead to neurodegenerative diseases.
In animals, the disease is known as Scrapie in sheep and goats, Bovine Spongiform Encephalopathy (BSE) in cattle, and Chronic Wasting Disease in ungulates (deer and elk, mainly in North America). In humans, the most frequent form is sporadic Creutzfeldt-Jakob disease with an incidence of approximately 1/1,000,000 persons per year worldwide. However, there are further very rare clinical forms, caused mainly by genetic mutation. These include Fatal Familial Insomnia disorder and Gerstmann-Sträussler-Scheinker Syndrome.