Japanese
English
- 有料閲覧
- Abstract 文献概要
- 1ページ目 Look Inside
- 参考文献 Reference
はじめに
プリオン病は,“プリオン”の脳内増殖により起こるヒトおよび動物の神経変性疾患である1)。動物プリオン病のプロトタイプであるヒツジのスクレーピー(scrapie)はヒトに感染しないことがこれまでの疫学的調査から示唆され,動物からヒトへの感染にはいわゆる“種の壁”といわれる大きなバリアーが存在すると考えられてきた2)。しかし,英国で大量に発生した牛海綿状脳症(bovine spongiform encephalopathy:BSE,または狂牛病)がヒトに感染し,新型クロイツフェルト・ヤコブ病(new variant Creutzfeldt-Jakob disease:nvCJD)を引き起こすという事実は3,4),あるタイプの動物プリオン病は種の壁を乗り越えてヒトに感染する可能性を示した。また英国では,nvCJDに感染しているヒトの血液を輸血されたヒトが後にnvCJDを発病した例が4例報告され,nvCJDが血液を介しヒトに2次感染する可能性も示された5)。しかし,プリオン病に対する有効な治療法は開発されていない。
本稿では,プリオンおよびプリオン病について概説するとともに,プリオン病の治療開発の現状について紹介する。
Abstract
Prion diseases are fatal infectious neurodegenerative disorders; examples include the Creutzfeldt-Jakob disease affecting humans and bovine spongiform encephalopathy in cattle. The causative agents of these diseases―the prions―are thought to consist of the pathogenic isoform of the prion protein PrPSc,which is produced by the conformational conversion of the normal isoform PrPC. Many lines of evidence indicate that the constitutive conversion of PrPC to PrPSc,resulting in a marked accumulation of PrPSc in the brain,is a central event in the pathogenesis of prion diseases. A large number of compounds have been identified as anti-prion agents and capable of reducing the PrPSc levels in infected cells. Some of these compounds have been found to be partially effective in infected animals,thus resulting in the prolongation of the incubation or survival times and a few of these compounds were or are under clinical trials. However,none of these compounds have proven to be therapeutically effective against this group of diseases. This is probably because (1) these compounds fail to cross the blood-brain barrier and (2) their effectiveness is reduced because they are administered only to patients with clinically advanced disease owing to a lack of diagnostic indicators for presymptomatic individuals. In this communication,we systematically list these anti-prion compounds and summarize their effectiveness and possible mechanisms of action.
Copyright © 2009, Igaku-Shoin Ltd. All rights reserved.