Prions Creutzfeldt-Jakob disease

The transmissible spongiform encephalopathies, or prion diseases, are fatal neurodegenerative diseases characterized by spongiform changes, astrocytic gliomas, and neuronal loss resulting from the deposition of insoluble protein aggregates in neural cells. They include Creutzfeldt-Jakob disease in humans, scrapie in... 

Prions—protein particles that lack nucleic acid— cause fatal transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease, scrapie, and bovine spongiform encephalopathy. Prion diseases involve an altered secondary-tertiary strucmre of a namrally occurring protein, PrPc. When PrPc interacts with its pathologic isoform PrPSc, its conformation is transformed from a predominantly a-helical strucmre to the P-sheet strucmre characteristic of PrPSc. 

Microorganisms surviving M. tuberculosis Bacterial spores HBV and prions as in Creutzfeldt-Jakob disease Bacterial spores Prions Extreme challenge of resistant bacterial spores Prions (insufficient data)... 

Creutzfeldt-Jakob disease (CJD) New variant CJD Gerstmann-Straussler-Scheinker disease Fatal familial insomnia Kuru Prion protein Extracellular deposits... 

Human prion disease models have also been developed in mice [154,155]. Crossing the species barrier into an experimentally accessible animal system, the prions responsible for Creutzfeldt Jakob disease, new variant CJD, Gerstmann-Straussler-Scheinker disease, and fatal familial insomnia produce a reproducible time-dependent neuronal degeneration leading to death. 

CREUTZFELDT-JAKOB DISEASE AND OTHER PRION DISEASES 662... 

Palmer, M. S., Dryden, A. J., Hughes, J. T. and Collinge, J. Homozygous prion protein genotype predisposes to sporadic Creutzfeldt-Jakob disease. Nature 352 340-342,1991. 

The prion diseases are a closely related group of neuro-degenerative conditions which affect both humans and animals. They have previously been described as the subacute spongiform encephalopathies, slow virus diseases and transmissible dementias, and include scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and the human prion diseases, Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler-Scheinker disease (GSS), fatal familial insomnia (FFI) and kuru. Prion diseases are... 

Giaccone, G., Canciani, B., Puoti, G., Rossi, G., Goffredo, D., Iussich, S., Fociani, P., Tagliavini, F., and Bugiani, O. (2000). Creutzfeldt-Jakob disease Carnoy s fixative improves the immunohistochemistry of the proteinase K-resistant prion protein. Brain Pathol. 10, 31-37. 

The normal cellular form of prion protein (PrPc) can exist as a Cu-metalloprotein in vivo (492). This PrPc is a precursor of the pathogenic protease-resistant form PrPsc, which is thought to cause scrapie, bovine spongiform encephalopathy (BSE), and Creutzfeldt—Jakob disease. Two octa-repeats of PHGGGWGQ have been proposed as Cu(II) binding sites centered on histidine (493). They lack secondary and tertiary structure in the absence of Cu(II). Neurons may therefore have special mechanisms to regulate the distribution of copper. 

Bovine spongiform encephalopathy (BSE or mad cow disease) is a progressive neurological degenerative disease in cattle. It is caused by a mutated protein called a prion. BSE was first reported in the United Kingdom in 1986. Creutzfeldt-Jakob disease (CJD) is a rare disease that occurs in humans. Evidence to date indicates it is possible for humans to acquire CJD after consuming BSE-contaminated cattle products. 

With the background of the mad cow crisis in Europe, questions relating to the prion diseases have attracted intensive interest. It is now widely accepted that prion diseases, such as Creutzfeldt-Jakob disease (CJd) in humans and bovine spongiform encephalopathy (BSE) are caused by a conformational change of the prion protein (PrP) from a normally folded cellular form, PrP ", to an alternate, aggregation-prone, pathogenic scrapie form,... 

The use of hGH extracted from the pituitaries of deceased human donors came to an abrupt end in 1985, when a link between treatment and Creutzfeldt-Jakob disease (CJD, a rare, but fatal, neurological disorder) was discovered. In this year, a young man who had received hGH therapy some 15 years previously died from CJD, which, investigators concluded, he had contracted from infected pituitary extract (CJD appears to be caused by a prion). At least an additional 12 CJD cases suspected of being caused in the same way have subsequently been documented. Fortunately, several recombinant hGH (rhGH) preparations were coming onstream at that time (Table 8.8), and now all hGH preparations used clinically are derived from recombinant sources. Currently, in excess of 20 000 people are in receipt of rhGH therapy. 

Like any other protein, the molecular structure of the prion is subject to conformational flexibility and to various thermal-induced fluctuations between varying conformational states. However, if these fluctuations permit the PrP conformation to be attained, then this abnormal conformer promotes the widespread conversion of PrP to PrP , leading to the precipitous deposition of the abnormal protein throughout the brain (mirrored by the rapid and relentlessly downhill clinical course). This pathological self-propagating shape conversion of a-helical PrP to P-sheet PrP may in principle be initiated by a seed PrP molecule in the neurotoxic conformation. This explains the transmissibility of prion diseases and accounts for how susceptible humans exposed to beef from an animal with mad cow disease develop variant Creutzfeldt-Jakob disease. 

Prion diseases have attracted immense attention over the past decade, prompted, in part, by the outbreak of mad cow disease in the United Kingdom. The most common prion disease is sporadic Creutzfeldt-Jakob disease (CJD). Clinically, CJD is characterized by a rapidly progressive dementia accompanied variably by early-onset seizures, insomnia, disordered movements, and psychiatric disturbances the disease is uniformly fatal. Histochemically, the principal pathological feature of prion disease is the abnormal accumulation of an amyloid-like material composed of prion protein (PrP), which is encoded by a single gene on the short arm of chromosome 20. 

Because they are derived from cattle, there is a concern that gelatins might be vehicles for the transmission of the prion agent responsible for bovine spongiform encephalopathy (BSE) in cattle and variant Creutzfeldt-Jakob disease (vGD) in humans. There is at present no evidence that these products have contributed to the transmission of BSE or vCJD. However, the incubation period may be up to several years, and due prudence is warranted when such products are used. 

Growth hormone is a 191-amino-acid peptide with two sulfhydryl bridges. Its structure closely resembles that of prolactin. In the past, medicinal GH was isolated from the pituitaries of human cadavers. However, this form of GH was found to be contaminated with prions that could cause Creutzfeldt-Jakob disease. For this reason, it is no longer used. Somatropin, the recombinant form of GH, has a 191-amino acid sequence that is identical with the predominant native form of human GH. 

This disease develops when an abnormal prion protein present in the cadaveric material induces a cascade of conformational changes in host protein. Creutzfeldt-Jakob disease in recipients of somatropin differs from the sporadic form, in that it usually presents with cerebellar signs rather than cognitive impairment, and also in the prominence of prion protein amyloid plaques in nervous tissue (18). In a review, 139 cases of Creutzfeldt-Jakob disease were identified worldwide in people treated with cadaveric somatropin before recombinant human growth hormone became available in the mid-1980s (19). The prevalence of this fatal neurodegenerative condition in recipients of somatropin ranges from 0.3% in the USA to 4.4% in France. Creutzfeldt-Jakob disease has been reported to start at 4-30 years after therapy with cadaveric somatropin (18), so that further cases are anticipated and continue to be reported (20). 

Haywood, P. A. R., Bell, J. E., and Ironside, J. W. 1994. Prion protein immunohistochemistry The development of reliable protocols for the investigation of Creutzfeldt-Jakob disease. Neuropathol. Appl. Neurobiol. 20 375-383. 

Zanusso, G., Righetti, P. G., Ferrari, S., Terrin, L., Farinazzo, A., Cardone, F., et al. (2002) Two-dimensional mapping of three phenotype-associated isoforms of the prion protein in sporadic Creutzfeldt-Jakob disease. Electrophoresis 23, 347-355. 

Transmissible prion disease of cattle variation of Creutzfeldt-Jakob disease. 

Prions are believed to cause Creutzfeldt-Jakob disease, also known as Mad Cow disease. 

---