Argyrophilic meshwork structures in the cerebral cortex of patients with progressive supranuclear palsy

Tau-positive glial inclusions in progressive supranuclear palsy, corticobasal degeneration and Pick's disease

The presence of tau-positive glial inclusions has been recently found a consistent feature in the brains of patients with progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Pick's disease (PiD). These inclusions are classified based on cellular origin as tau-positive astrocytes, presumably either fibrillary or protoplasmic, coiled bodies and glial threads. Immunohistochemically, their major structural component is abnormal tau proteins, similar to those found in Alzheimer's disease. Nevertheless, their morphology, including ultrastructural profile, has been suggested to be distinctive for each disease. The profile and extent of particular glial inclusions correlate well with disease phenotype. Highly characteristic correlations include tufts of abnormal fibers in PSP, astrocytic plaques and dense glial threads in CBD and ramified astrocytes and small Pick body-like inclusions in PiD. The significance of the inclusions in disease pathogenesis and their biochemical characteristics remain to be clarified. Nevertheless, these distinctive glial lesions most likely reflect fundamental alterations in isoform composition of tau as well as its specific cellular and regional expression in sporadic tauopathies.

A qualitative and quantitative study of grumose degeneration in progressive supranuclear palsy

Grumose degeneration (GD) of the dentate nucleus is a common feature in progressive supranuclear palsy (PSP), but its pathogenesis has not been well studied, and its clinical significance remains unknown. This report describes a quantitative study of GD in 9 cases of PSP using image analysis with single- and double-immunolabeling, as well as histochemical stains for myelin and axons. GD was associated with demyelination, axonal loss, glial tau pathology, and microgliosis in regions juxtaposed to the dentate nucleus (DN). Specifically, demyelination and microgliosis were prominent in the superior cerebellar peduncle (SCP), dentate hilus, and cerebellar hemispheric white matter. Tau pathology and microgliosis were less prominent in the DN itself. The degree of myelin loss correlated with the tau burden in the SCP. GAP-43, which is a phosphoprotein known to be involved in axonal growth and sprouting, was decreased in the DN of PSP, and the degree of GAP-43 loss correlated with severity of GD. These results suggest that GD may be related to progressive pathology in the dentatorubrothalamic tract as well as the cerebellar hemispheric white matter, and that GD may be a consequence of concurrent degeneration in both output from and input to the DN. The results further suggest a possible role for oligodendroglial and myelin pathology in the pathogenesis of PSP.

Morphologic difference of neuropil threads in Alzheimer's disease, corticobasal degeneration and progressive supranuclear palsy: a morphometric study

Using Gallyas-Braak's silver stain, neuropil threads (NTs) in Alzheimer's disease (AD), corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) were analyzed morphologically and morphometrically. The NT density was highest in the cerebral cortical layer V in AD and CBD, and in the subcortical white matter in PSP. An overlaid, two-dimensional, camera lucida drawing revealed differences in the fine profile of NTs among these three disease groups. The differences were confirmed by computerized feature analysis which revealed differences in maximum length, breadth, Feret's angle and orientation of the NTs. Unlike a previous assumption that all NTs have a similar appearance, our study revealed that NTs in AD, CBD and PSP were distinctively different with respect to their morphology.