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Ultrastructural studies of experimental scrapie and Creutzfeldt-Jakob disease in hamsters. I. Alterations of myelinated axons

100%

Liberski P. P., Bratosiewicz-Wasik J., Gajdusek D. C., Brown P.

Acta Neurobiologiae Experimentalis

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2002

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vol. 62

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issue 3

121-129

EN

Classical and ultrastructural neuropathology of prion diseases are generally well described. Here we report that alterations of myelinated fibres in hamsters infected either with polioencephalopathic strains of scrapie or panencephalopathic strains of CJD (Echigo-1) are virtually identical and differ only quantitatively. In contrast, mice infected with the panencephalopathic Fujisaki strain of CJD exhibited much more elaborate changes of myelinated fibres.

2

Ultrastructural studies of experimental scrapie and Creutzfeldt-Jakob disease in hamsters. II. Astrocytic and macrophage reaction toward the axonal destruction

100%

Liberski P. P., Bratosiewicz-Wasik J., Gajdusek D. C., Brown P.

Acta Neurobiologiae Experimentalis

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2002

|

vol. 62

|

issue 3

131-139

EN

We report here the microglial (macrophage) and astrocytic reaction in several models of transmissible spongiform encephalopathies (TSEs) or prion diseases. With the low power electron microscopy it was readily apparent that myelinated vacuoles were surrounded by cells and their processes. The latter belonged either to hyperplastic reactive astrocytes or to macrophages. Typically reactive astrocytes exhibited cytoplasm filled with innumerable glial filaments and, occasionally, other organelles (like cilia) and abundant tortuous intercellular junctions of adhesive plaque junction type. Desmosome-like junctions connecting astrocytic elements were also seen. As described earlier, astrocytic processes were occasionally interdigitated with oligodendroglial cells and their processes. Two types of macrophages were readily described. The majority of them exhibited electron-dense cytoplasm and numerous ?empty? vacuoles (digestive chambers) containing cellular debris. Occasional vacuoles were surrounded by a thin collar reminiscent of ?lyre-like inclusions? of the second type of macrophages. The latter were rare and characterized by numerous ?lyre-like? inclusions. Several mylinated fibres were clearly engulfed by the cytoplasm of a macrophage containing unusual annulate lamellae.

3

How do neurons degenerate in prion diseases or transmissible spongiform encephalopathies (TSEs): neuronal autophagy revisited

100%

Liberski P. P., Gajdusek D. C., Brown P.

Acta Neurobiologiae Experimentalis

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2002

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vol. 62

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issue 3

141-147

EN

As in other neurodegenerative diseases such as Alzheimer?s disease, neurons in prion diseases or transmissible spongiform encephalopathies (TSEs) die via programmed cell death of which the apoptotic process is relatively well characterized. A subcellular alteration linked to apoptosis is the formation of autophagic vacuoles, which we and others demonstrated in CJD- and scrapie-affected rodent brains. Autophagy may co-exist with apoptosis or may precede it and the process may be induced by apoptotic stimuli. Here, we extend these observations using different model of scrapie and CJD. Both scrapie models (the 263K and 22C-H) demonstrated autophagic vacuoles with the same frequency; hence, they will be described together. While the following changes had been observed simultaneously in different areas of the same sample, this description is organised as if it followed a sequence of events. First, a part of the neuronal cytoplasm was sequestrated by concentric arrays of membrane; that part of the cytoplasm closed by membranes appeared relatively normal but its density often appeared increased. Next, electron density of the central dramatically increased. Then, membranes proliferated within the cytoplasm in a labyrinth-like manner and an area sequestrated by these membranes enlarged and became more complex structure consisting of vacuoles, electron-dense area and areas of normally-looking cytoplasm connected with convoluted membranes. Finally, a large area of the cytoplasm was transformed into a collection of autophagic vacuoles of different sizes. Virtually identical alterations, albeit with much lower frequency, were seen in terminally ill CJD-affected hamsters.

4

Exuberant cellular reaction of the optic nerves in experimental Creutzfeldt-Jakob disease

76%

Liberski P. P., Sikorska B., Bratosiewicz-Wasik J., Walis A., Brown P., Brown D.

Acta Neurobiologiae Experimentalis

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2003

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vol. 63

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issue 4

309-318

EN

We report here on the exuberant glial reaction in the optic nerves affected by prion diseases. Optic nerves from CJD- and GSS-, and scrapie-infected mice and hamsters showed severe pathology. These lesions were qualitatively indistinguishable from each other but were more intense in the Fujisaki model than in the hamsters inoculated with Echigo-1. Exuberant cellular reaction comprised of macrophages containing numerous mitochondria, abundant rough endoplasmic reticulum, and secondary lysosomes filled with digested myelin debris, electron-dense material and occasionally, entire myelin-bound vacuoles were readily observed in both models. Macrophages actively digesting myelin fragments and containing lyre-like bodies and paracrystalline inclusions were frequently noted. Some macrophages extended long filopodia to form labyrinth-like structures, and within a few macrophages, concentric arrays of cisterns and channels sequestrated part of the cytoplasm. An analogous network of narrow cisterns was seen to surround whole segments of the myelinated fibers.

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Ultrastructural studies of experimental scrapie and Creutzfeldt-Jakob disease in hamsters. I. Alterations of myelinated axons

Ultrastructural studies of experimental scrapie and Creutzfeldt-Jakob disease in hamsters. II. Astrocytic and macrophage reaction toward the axonal destruction

How do neurons degenerate in prion diseases or transmissible spongiform encephalopathies (TSEs): neuronal autophagy revisited

Exuberant cellular reaction of the optic nerves in experimental Creutzfeldt-Jakob disease