Prion diseases, always a threat?

Abstract

Prion disease is caused by prion which was identified as a causative factor of transmissible spongiform encephalopathy such as Creutzfeldt-Jakob disease (CJD) and means proteineaceous infectious particle. Prion diseases are devastating neurodegenerative disorders of human and many animals including sheep, cows, deer, cats and camels. CJD presents usually as a rapidly progressive dementia with other symptoms inevitably resulting in death often in months with no available therapy. Like other neurodegenerative diseases, prion diseases are classified into sporadic and genetic forms. In addition, there is the third category of environmentally acquired form. This type includes kuru and iatrogenic CJD due to human dura mater grafts or human pituitary derived hormones as well as variant CJD transmitted through food contaminated with prion of bovine spongiform encephalopathy (BSE). BSE and variant CJD has been almost controlled but chronic wasting disease, prion disease of deer, is spreading widely in North America and South Korea and recently in northern Europe. Recently Aß, α-synuclein and other proteins related to Alzheimer's, Parkinson's and other diseases were reported to have prion features such as transmission to animals. Aß transmission to human was suggested in iatrogenic CJD cases as well as in cerebral amyloid angiopathy cases with cerebral bleeding long after childhood neurosurgery with or without cadaveric dura. These findings indicate prion diseases due to various prions, namely various transmissible proteins appear to be a threat particularly in this longevity society. To overcome prion diseases is one of the top priority in our society.