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Spongiform encephalopathy: a neurocytologist's viewpoint with a note on Alzheimer's disease

E G Gray

    Neuropathology and Applied Neurobiology
    |March 1, 1986
    PubMed

    Insights

    Spongiform encephalopathy research challenges early findings and examines current theories. New ultrastructural studies suggest dendritic microtubule loss explains neurological decline in Creutzfeldt-Jakob disease and Alzheimer's disease.

    Area of Science:

    • Neuroscience
    • Neuropathology
    • Cell Biology

    Background:

    • Spongiform encephalopathy (SE) research has focused on early pathological changes and current theories like the spiroplasma and prion hypotheses.
    • Existing theories for SE pathogenesis, including the prion (6 nm filament) theory, are not yet fully convincing.

    Purpose of the Study:

    • To investigate early pathological changes in spongiform encephalopathy, specifically kuru.
    • To evaluate the spiroplasma and prion theories in the later stages of SE.
    • To explore the role of dendritic cytoskeleton in neurodegenerative diseases, including Creutzfeldt-Jakob disease (CJD) and Alzheimer's disease (AD).

    Main Methods:

    • Ultrastructural studies of brain tissue from patients with Creutzfeldt-Jakob disease.
    • Experimental modeling involving depletion or loss of dendritic microtubules.
    • Comparative analysis with observations in kuru and Alzheimer's disease.

    Main Results:

    • No very early pathological changes were observed in kuru, challenging previous reports of membrane lamellation.
    • Extensive dismantling of the dendritic microtubule cytoskeleton was observed in Creutzfeldt-Jakob disease brain.
    • Loss of dendritic cytoskeleton correlates with impaired cytotransport and abolished postsynaptic events, potentially explaining neurological symptoms.
    • Spongy vacuoles observed in SE may be fixation artifacts, as suggested by experimental models of microtubule depletion.
    • Similar loss of dendritic microtubules was noted in Alzheimer's disease.

    Conclusions:

    • Dendritic microtubule cytoskeleton loss is a significant pathological feature in Creutzfeldt-Jakob disease, offering an explanation for neurological dysfunction and mortality.
    • The observed microtubule loss in Alzheimer's disease suggests a potential common pathway in neurodegeneration.
    • Further investigation into the role of microtubules and the nature of vacuoles in SE is warranted.

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