Achromatic neurons in the cortex of progressive supranuclear palsy

Progressive supranuclear palsy: a review of co-existing neurodegeneration

OBJECTIVES

The neuropathological findings of 32 progressive supranuclear palsy (PSP) cases over a period of 17 years were reviewed.

RESULTS

Of the 26 cases with adequate clinical data, 20 patients either presented with cognitive dysfunction or developed a cognitive impairment subsequently during the course of the disease. Co-existing changes of argyrophilic grains and corticobasal degeneration (CBD) were found in 28% and 32% of the cases respectively. Alzheimer-related pathology was found in 69% of cases but only 18.75% of cases fulfilled the consortium to establish a registry for Alzheimer's disease (CERAD) criteria for either definite or probable Alzheimer's disease. Lewy bodies were noted in four cases (12.5%), all in the subcortical regions. Only seven cases of PSP showed no pathological evidence of other co-existing neurodegenerative diseases. The severity of the cerebrovascular pathology in this cohort was insufficient to explain any clinical symptomatology.

CONCLUSIONS

As in previous studies, this study has demonstrated the frequent co-existence of pathological changes usually noted in other neurodegenerative diseases in PSP. Whether these co-existing pathological changes contribute to the cognitive impairment in PSP remains uncertain.

Progressive supranuclear palsy (PSP): a quantitative study of the pathological changes in cortical and subcortical regions of eight cases

In eight cases of progressive supranuclear palsy (PSP), neurofibrillary tangles (NFT) were numerous in the substantia nigra (SN), red nucleus (RN), locus caeruleus (LC), pontine nuclei (PN), and inferior olivary nucleus (ION) and abnormally enlarged neurons (EN) in the ION, LC and PN. Loss of Purkinje cells was evident in the cerebellum. Tufted astrocytes (TA) were abundant in the striatum, SN and RN and glial inclusions ('coiled bodies') (GI) in the midbrain (SN, RN) and pons (LC). Neuritic plaques were frequent in one case. NFT, GI, and TA densities were uncorrelated in most areas. NFT and EN densities were positively correlated in the midbrain and surviving neurons and disease duration in several areas. These results suggest: 1) predominantly subcortical pathology in PSP with widespread NFT while TA and GI have a more localized distribution, 2) little correlation between neuronal and glial pathologies, and 3) shorter duration cases may be more likely to develop cortical pathology.

Spatial patterns of the pathological changes in neuronal intermediate filament inclusion disease (NIFID): an α-internexin immunohistochemical study

Neuronal intermediate filament inclusion disease (NIFID) is characterized by alpha-internexin positive neuronal cytoplasmic inclusions (NCI), swollen achromatic neurons (SN), neuronal loss, and gliosis. This study tested: 1) whether the spatial patterns of the lesions was topographically organized in areas of the frontal and temporal lobe and 2) whether a spatial relationship exists between the NCI and SN. The NCI were distributed in regular clusters and in a quarter of these areas, the clusters were 400-800 microm in diameter approximating to the size of the cells of origin of the cortico-cortical pathways. Variations in the density of the NCI were positively correlated with the SN. Hence, cortical degeneration in NIFID appears to be topographically organized and may affect the cortico-cortical projections, the clusters of NCI and SN developing within the same vertical columns of cells.

Spatial topography of the neurofibrillary tangles in cortical and subcortical regions in progressive supranuclear palsy

OBJECTIVE

To study the topography of neurofibrillary tangles (NFT) in cortical and subcortical areas in progressive supranuclear palsy (PSP).

METHODS

Pattern analysis was carried out on tau-positive NFT in eight PSP cases.

RESULTS

Of the areas studied, NFT were randomly distributed in 68%, regularly distributed in 3%, and clustered in 29%. A regular distribution of clusters was more frequent in cortical than subcortical areas.

CONCLUSION

NFT topography in subcortical areas was similar to inclusions in the synucleinopathy multiple system atrophy (MSA) but in cortical areas was comparable to other tauopathies.

Corticobasal ganglionic degeneration and progressive supranuclear palsy presenting with cognitive decline

Corticobasal ganglionic degeneration (CBGD) and progressive supranuclear palsy (PSP) were originally described in the sixties as predominantly motor syndromes. Over the years, the detailed study of additional cases of CBGD has shown that it is a distinctive histological entity which can often present as dementia or aphasia. Although some pathological features of CBGD overlap with those of other forms of non-Alzheimer non-Lewy body dementia, the distribution and relative number of these abnormalities and the distinctive pattern of tau immunodeposits allows the distinction of CBGD from Pick's disease and fronto-temporal dementia. In contrast, PSP only rarely presents with prominent dementia or behavioral changes. In these unusual PSP cases, care must be taken to exclude the diagnoses of CBGD and familial tangle-only dementia.

Neuropathological changes in ten cases of neuronal intermediate filament inclusion disease (NIFID): a study using α-internexin immunohistochemistry and principal components analysis (PCA)

Ten cases of neuronal intermediate filament inclusion disease (NIFID) were studied quantitatively. The alpha-internexin positive neurofilament inclusions (NI) were most abundant in the motor cortex and CA sectors of the hippocampus. The densities of the NI and the swollen achromatic neurons (SN) were similar in laminae II/III and V/VI but glial cell density was greater in V/VI. The density of the NI was positively correlated with the SN and the glial cells. Principal components analysis (PCA) suggested that PC1 was associated with variation in neuronal loss in the frontal/temporal lobes and PC2 with neuronal loss in the frontal lobe and NI density in the parahippocampal gyrus. The data suggest: 1) frontal and temporal lobe degeneration in NIFID is associated with the widespread formation of NI and SN, 2) NI and SN affect cortical laminae II/III and V/VI, 3) the NI and SN affect closely related neuronal populations, and 4) variations in neuronal loss and in the density of NI were the most important sources of pathological heterogeneity.

Office of Rare Diseases neuropathologic criteria for corticobasal degeneration

A working group supported by the Office of Rare Diseases of the National Institutes of Health formulated neuropathologic criteria for corticobasal degeneration (CBD) that were subsequently validated by an independent group of neuropathologists. The criteria do not require a specific clinical phenotype, since CBD can have diverse clinical presentations, such as progressive asymmetrical rigidity and apraxia, progressive aphasia, or frontal lobe dementia. Cortical atrophy, ballooned neurons, and degeneration of the substantia nigra have been emphasized in previous descriptions and are present in CBD, but the present criteria emphasize tau-immunoreactive lesions in neurons, glia, and cell processes in the neuropathologic diagnosis of CBD. The minimal pathologic features for CBD are cortical and striatal tau-positive neuronal and glial lesions, especially astrocytic plaques and thread-like lesions in both white matter and gray matter, along with neuronal loss in focal cortical regions and in the substantia nigra. The methods required to make this diagnosis include histologic stains to assess neuronal loss, spongiosis and ballooned neurons, and a method to detect tau-positive neuronal and glial lesions. Use of either the Gallyas silver staining method or immunostains with sensitive tau antibodies is acceptable. In cases where ballooned neurons are sparse or difficult to detect, immunostaining for phospho-neurofilament or alpha-B-crystallin may prove helpful. Methods to assess Alzheimer-type pathology and Lewy body pathology are necessary to rule out other causes of dementia and Parkinsonism. Using these criteria provides good differentiation of CBD from other tauopathies, except frontotemporal dementia and Parkinsonism linked to chromosome 17, where additional clinical or molecular genetic information is required to make an accurate diagnosis.

Regional quantitative analysis of tau-positive neurons in progressive supranuclear palsy: comparison with Alzheimer's disease

In patients with progressive supranuclear palsy (PSP), various tau-positive abnormal structures are found in the cerebral cortex as well as in the subcortical nuclei. Similar tau-positive abnormalities are also identified in cortico-basal degeneration (CBD). It is therefore questionable as to whether PSP can be neuropathologically differentiated from CBD. It also remains nuclear whether neurofibrillary tangles (NFT) in the cerebral cortex of PSP patients consist of PSP-NFT or concomitant Alzheimer's disease (AD)-NFT, although there have been some reports suggesting that PSP- and AD-NFT are different with respect to distribution pattern and biochemical character. In this study, a regional quantitative analysis of the distribution and antigenicity of tau-positive neurons (TPN) was performed in PSP cases and compared with that in AD cases. TPN consisted of NFT with tangle-formation and pretangle neurons (PN) without tangle-formation. In addition, NFT were subdivided into mature and immature NFT according to the difference of staining properties with anti-tau-related antibodies. The comparison of the TPN of the PSP cases with those of the AD cases revealed that the degree of tangle-formation in the TPN of AD was similar in all of the examined regions, while that in the TPN of PSP varied according to the region and case. Moreover, the NFT in the PSP and AD cases had different distributions according to the cortical layer and subnucleus, even in the common predilection sites of PSP and AD, suggesting that NFT in these regions of the PSP cases consist mainly of PSP-NFT. In addition, the PSP cases could be divided into two groups according to the difference of the tangle-formation of TPN; group I with typical PSP pathology and group II with atypical PSP pathology similar to CBD. This suggests that there is a continuity between PSP and CBD with respect to the distribution and antigenicity of TPN.

Unusual clinical presentations of cortical-basal ganglionic degeneration

Cortical-basal ganglionic degeneration classically presents predominantly as a motor disorder with a unique constellation of histological alterations characterized by the presence of neuronal loss and gliosis in a selective distribution, swollen achromasic neurons, and extensive deposition of abnormal tau in neurons and glia. We now report 3 patients with this distinctive pathology who presented with cognitive changes and only mild or delayed motor symptoms. In 2 patients with severe dementia, pathological changes were extensive in the anterior frontal lobe, amygdala, and hippocampus. In a third patient who had an isolated speech disturbance for 5 years before developing the more typical motor features of cortical-basal ganglionic degeneration, the most severe changes were observed in the left motor cortex and adjacent Broca's area. It is therefore apparent that the histological changes of cortical-basal ganglionic degeneration result in a variety of clinical presentations depending on the topography of the lesions. On this basis we conclude that cortical-basal ganglionic degeneration should be considered in the differential diagnosis of language disturbances and dementia, particularly when the latter is accompanied by frontal lobe symptomatology, early speech alterations, or parkinsonism.