Acta Medica Okayama 72巻 3号
2018-06 発行

Astrocytic Tau Pathologies in Argyrophilic Grain Disease and Related Four-repeat Tauopathies

Ikeda, Chikako Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Yokota, Osamu Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Miki, Tomoko Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Takenoshita, Shintaro Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Ishizu, Hideki Department of Psychiatry, Zikei Institute of Psychiatry
Terada, Seishi Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Yamada, Norihito Department of Neuropsychiatry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Publication Date
2018-06
Abstract
Neurodegenerative diseases in which tau accumulation plays a cardinal role in the pathogenic process are called tauopathies, and when tau isoforms having four repeats of the microtubule binding sites, four-repeat tau, are selectively accumulated as pathological hallmarks, the term four-repeat tauopathy is used. The major four-repeat tauopathies are progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and argyrophilic grain disease (AGD). Historically, neuronal cytopathologies, e.g., neurofibrillary tangles and ballooned neurons, were emphasized as characteristic lesions in PSP and CBD. Now, however, astrocytic tau pathologies, i.e., tufted astrocytes (TAs) and astrocytic plaques (APs), are considered to be highly disease-specific lesions. Although granular/fuzzy astrocytes (GFAs) frequently develop in the limbic system in AGD cases, the specificity is not conclusive yet. Some AGD cases have a few TAs, and to a lesser frequency, a few APs in the frontal cortex and subcortical nuclei. The number of astrocytic tau pathologies including TAs and GFAs increases with the progression of AGD. In this paper, histopathological features of astrocytic tau pathologies in PSP, CBD, and AGD are first reviewed. Then, recent findings regarding the coexistence of these tauopathies are summarized from a viewpoint of astrocytic tau pathologies. Further biochemical and pathological studies focusing tau-positive astrocytic lesions may be useful to increase understanding of the pathological process in four-repeat tauopathies and to develop novel therapeutic strategies for patients with these diseases.
Document Type
Review
Keywords
astrocytic plaque
four-repeat tau
globular glial inclusion
granular fuzzy astrocyte
tufted astrocyte
Link to PubMed
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