Clinical and pathological features affecting cardiac sympathetic denervation in autopsy-confirmed dementia with Lewy bodies.

BACKGROUND AND PURPOSE: The aim was to clarify the features affecting cardiac sympathetic denervation in autopsy-confirmed dementia with Lewy bodies (DLB) patients. METHODS: Fifty-four autopsy-confirmed DLB patients were enrolled. Tissue samples of the left ventricular anterior wall were immunostained with anti-tyrosine hydroxylase antibody to identify catecholaminergic nerve axons. Immunostained areas were quantified as residual cardiac sympathetic nerve (CSN) axons and the relationship between the degree of residual CSN axons and clinical and neuropathological features was examined. RESULTS: Virtually all patients showed small amounts of residual CSN axons (0.87%, range 0.02%-9.98%), with 50 patients (92.6%) showing <2.0% of residual axons. The patients who showed psychological symptoms within the first year of the disease had significantly more residual CSN axons than the remaining patients did (1.50% vs. 0.40%, P < 0.01). Patients with a short disease duration and neocortical-type Lewy body pathology tended to have more preserved CSN axons, although this difference was not statistically significant. Fifty-three patients (98.1%) who had neurofibrillary tangles in the brain and strong concomitant Alzheimer's disease pathology also had statistically significantly more preserved CSN axons. The patient with the most preserved CSN axons showed different characteristics from the results, except for the first symptom. CONCLUSION: Psychological symptoms within the first year of the disease, a short disease duration, neocortical-type Lewy body pathology and strong concomitant Alzheimer's disease pathology may be related to mild CSN degeneration in DLB patients. Thus, DLB patients with broad Lewy body pathology in the brain in the early stages may show mild CSN degeneration.

Local extension of HMGB1 in atherosclerotic lesions of human main cerebral and carotid arteries.

High mobility group box 1 protein (HMGB1) is a non-histone chromosomal protein which is highly conserved, ubiquitous, and widely distributed. HMGB1 has multiple functions in the nucleus, including the maintenance of nucleosome structure, the regulation of gene transcription, and involvement in DNA recombination. HMBG1 is currently recognized to have a wide range of potential functions and pathological relevance. HMGB1 is released into the extracellular space from necrotic cells and from activated macrophages. HMGB1 binds to the receptor for advanced glycation end products, resulting in the induction of inflammatory cytokines, and to endothelial cell thrombomodulin. HMGB1 neutralization may also reduce the development of atherosclerosis and ameliorate brain infarction. We investigated the immunolocalization of HMGB1 in atherosclerotic lesions of human cerebral and carotid arteries using a specific antibody, and confirmed the detailed expression and cell type localization using double immunofluorolabeling. In the main cerebral arteries, this anti-HMGB1 antibody intensely immunolabeled both normal morphological vascular smooth muscle cells (VSMCs) within the tunica media and infiltrating VSMCs within the intima of thickened fibrous cap plaques. Endothelial cells were also positive for HMGB1. In carotid plaques, HMGB1-like immunoreactivity (IR) was intense in macrophages, although this IR decreased with increasing cell size. Medium-sized foam cells (50-150 µm) were the most intensely stained. This IR was also observed in the nuclei of foam cells and VSMCs. These findings may provide a basis for understanding the association of HMGB1 with atherosclerotic lesions of the cerebral and carotid arteries, and for constructing strategies to counteract atherosclerosis with anti-HMGB1 antibody.

Amnesia in frontotemporal dementia with amyotrophic lateral sclerosis, masquerading Alzheimer's disease.

A 68-year-old man with a clinical diagnosis of Alzheimer's disease (AD) later developed amyotrophic lateral sclerosis (ALS), which was confirmed at autopsy at age 72 years. Because neuronal loss and AD-type pathologies (Braak stage II for neurofibrillary tangles) were scant, TDP-43-positive intracytoplasmic inclusions in hippocampal dentate granular cells and in neurons in the subiculum and amygdala, even though small in amount, may represent the earliest lesions of ALS-related dementia and could be the cause of dementia in this patient. Although the persistent elevation of creatine kinase from the onset could be a pointer to the presence of motor involvement, more accurate characterization of dementia, which may differentiate ALS-related dementia and AD, is necessary.

Unmyelinated axons are more vulnerable to degeneration than myelinated axons of the cardiac nerve in Parkinson's disease.

AIMS: We recently demonstrated accumulation of α-synuclein aggregates of the cardiac sympathetic nerve in Parkinson's disease (PD) and a possible relationship between degeneration of the cardiac sympathetic nerve and α-synuclein aggregates. The aim of this study is to determine whether there is a difference in the degenerative process between unmyelinated and myelinated axons of the cardiac nerve. METHODS: We immunohistochemically examined cardiac tissues from four pathologically verified PD patients, nine patients with incidental Lewy body disease (ILBD) and five control subjects, using antibodies against neurofilament, myelin basic protein (MBP) and α-synuclein. First, we counted the number of neurofilament-immunoreactive axons not surrounded by MBP (unmyelinated axons) and those surrounded by MBP (myelinated axons). Next, we counted the number of unmyelinated and myelinated axons with α-synuclein aggregates. RESULTS: (i) The percentage of unmyelinated axons in PD (77.5 ± 9.14%) was significantly lower compared to that in control subjects (92.2 ± 2.40%). (ii) The ratio of unmyelinated axons with α-synuclein aggregates to total axons with α-synuclein aggregates in ILBD ranged from 94.4 to 100 (98.2 ± 2.18%). Among axons with α-synuclein aggregates, unmyelinated axons were the overwhelming majority, comprising 98.2%. CONCLUSION: These findings suggest that in PD unmyelinated axons are more vulnerable to degeneration than myelinated axons of the cardiac nerve, because α-synuclein aggregates accumulate much more abundantly in unmyelinated axons.

Attenuated nuclear shrinkage in neurones with nuclear inclusions of SCA1 brains.

BACKGROUND: Spinocerebellar ataxia type 1 (SCA1) is one of the autosomal dominant neurodegenerative disorders commonly linked to pathological expansion of the CAG repeat of the relevant gene. Nuclear inclusions and neurodegeneration are both triggered by this pathological expansion of the CAG/polyglutamine repeat on ataxin-1, but it remains to be determined whether or not nuclear inclusion formation is associated with accelerated neurodegeneration. OBJECTIVE: To examine the influence of nuclear inclusions on nuclear size and deformity in human brains from patients suffering from SCA1. MATERIAL: Pontine sections of brains obtained at necropsy from seven patients with SCA1 and five controls. METHODS: The size and deformity of each neuronal nucleus was quantified. Nuclei with and without inclusions were examined separately to assess the possible influence of nuclear inclusions on neurodegeneration. RESULTS: Nuclear shrinkage and deformity were more marked in SCA1 brains than in controls. This shrinkage was attenuated in neurones containing nuclear inclusions. CONCLUSIONS: The existence of nuclear inclusions in SCA1 is presumably linked to a mechanism that attenuates rather than accelerates nuclear shrinkage. This in vivo finding may provide a clue to constructing a rational therapeutic strategy for combating neurodegeneration associated with nuclear inclusions.

Paradoxical absence of nuclear inclusion in cerebellar Purkinje cells of hereditary ataxias linked to CAG expansion.

Degeneration of cerebellar cortex is one of the principal features of hereditary ataxias linked to expansion of CAG repeat. In an attempt to clarify possible correlation between neuronal depletion and neuronal intranuclear inclusions, both triggered by the pathological expansion of CAG repeat, cerebellar sections from SCA1, SCA2, SCA3, and DRPLA cases were immunostained with anti-ubiquitin or anti-expanded polyglutamine antibody (1C2) and were screened for the presence of neuronal intranuclear inclusions. Although the degree of cerebellar degeneration varied greatly, cerebellar Purkinje cells were uniformly characterised by the absence of neuronal intranuclear inclusion. Complete absence of neuronal intranuclear inclusion in Purkinje cells is apparently paradoxical and hardly explained if neuronal intranuclear inclusion formation is positively correlated to a mechanism accelerating neuronal death. It may, otherwise, suggest an intrinsic link between neuronal intranuclear inclusion formation and neurodegeneration in opposite directions in human Purkinje cells, more or less affected in these CAG repeat disorders.

Constant involvement of the Betz cells and pyramidal tract in amyotrophic lateral sclerosis with dementia: a clinicopathological study of eight autopsy cases.

We investigated clinicopathologically pyramidal signs, including hyperreflexia, Babinski sign, and spasticity, and the involvement of the primary motor cortex and pyramidal tract, in eight Japanese autopsy cases of amyotrophic lateral sclerosis (ALS) with dementia. Pyramidal signs were observed in seven (88%) of the eight autopsy cases. Hyperreflexia and Babinski sign were evident in seven (88%) and three (38%) patients, respectively, but spasticity was not observed in any of the eight patients. Loss of Betz cells in the primary motor cortex was evident in the seven cases in which this structure was examined. Astrocytosis in the fifth layer of the primary motor cortex was noticed in three cases. In all eight cases, involvement of the pyramidal tract was obvious in the medulla oblongata, but no involvement of the pyramidal tract was found in the midbrain. Involvement of the pyramidal tract in the spinal cord, particularly of large myelinated fibers, was observed in all six cases in which the spinal cord was examined. In ALS with dementia, pyramidal signs were shown to be present more frequently than previously believed, and the clinicopathological correlation between pyramidal signs and involvement of the pyramidal tract was obvious. Constant involvement of Betz cells and the pyramidal tract in ALS with dementia has not been reported. Our clinicopathological findings may make a contribution to the understanding of the clinicopathological hallmarks of this disorder. Furthermore, we believe that this study will also contribute to the elucidation of the nosological status of ALS with dementia.

Delayed-onset ataxia in mice lacking alpha -tocopherol transfer protein: model for neuronal degeneration caused by chronic oxidative stress.

alpha-Tocopherol transfer protein (alpha-TTP) maintains the concentration of serum alpha-tocopherol (vitamin E), one of the most potent fat-soluble antioxidants, by facilitating alpha-tocopherol export from the liver. Mutations of the alpha-TTP gene are linked to ataxia with isolated vitamin E deficiency (AVED). We produced a model mouse of AVED by deleting the alpha-TTP gene, which showed ataxia and retinal degeneration after 1 year of age. Because the brain alpha-TTP functions in maintaining alpha-tocopherol levels in the brain, alpha-tocopherol was completely depleted in the alpha-TTP(-/-) mouse brain, and the neurological phenotype of alpha-TTP(-/-) mice is much more severe than that of wild-type mice when maintained on an alpha-tocopherol-deficient diet. Lipid peroxidation in alpha-TTP(-/-) mice brains showed a significant increase, especially in degenerating neurons. alpha-Tocopherol supplementation suppressed lipid peroxidation and almost completely prevented the development of neurological symptoms. This therapy almost completely corrects the abnormalities in a mouse model of human neurodegenerative disease. Moreover, alpha-TTP(-/-) mice may prove to be excellent animal models of delayed onset, slowly progressive neuronal degeneration caused by chronic oxidative stress.

Different conformation of neuronal tau deposits distinguished by double immunofluorescence with AT8 and thiazin red combined with Gallyas method.

Different kinds of tau deposits were quantitatively investigated with thiazin red (TR), a fluorochrome that binds to fibrillary structures like neurofibrillary tangles (NFTs), in brains obtained at autopsy from patients with Alzheimer's disease (AD), Pick body (PB) disease, corticobasal degeneration (CBD) or diffuse NFTs with calcification (DNTC). After recording double-labeling fluorescence images with anti-paired helical filament tau (AT8) and TR, the sections were subjected to Gallyas method (GAL). This enabled three different staining properties to be compared on the identical neuron. AT8-positive neocortical neurons of AD and DNTC were fibrillary and uniformly positive for TR and GAL, consistently forming NFTs. NFTs lacking AT8 immunoreactivity (IR) were more frequent in DNTC than in AD, suggesting that evolution of NFTs is more accelerated in DNTC. Scarce TR staining in tau-positive neocortical neurons of CBD suggests their paucity of fibrillary structure. Since the affinity of TR for PB was not consistent, this may be dependent not only on the amount but also the characteristics of fibrillary structures. PBs were further characterized by the scarcity of GAL staining. This approach, which quantitatively clarifies differences between AT8-IR, TR and GAL, provides a morphological basis for further investigations of the different conformational states of tau from its deposition to fibril formation of various types.

Non-expanded polyglutamine proteins in intranuclear inclusions of hereditary ataxias--triple-labeling immunofluorescence study.

Neuronal intranuclear inclusions (NIIs) found in CAG/polyglutamine-expansion disorders contain both expanded polyglutamine and the gene product without the CAG repeat. The gene product containing expanded polyglutamine has, therefore, been considered to be a major component of NIIs. In this immunohistochemical study, we showed recruitment of ataxin-2, ataxin-3 and TATA box binding protein (TBP) into NIIs of the pontine neurons of spinocerebellar ataxia type (SCA) 1, SCA2, SCA3 and dentatorubral-pallidoluysian atrophy brains. Triple-labeling immunofluorescence demonstrated colocalization of ataxin-2 and ataxin-3 in NIIs containing expanded polyglutamine, irrespective of the disease examined. These in vivo findings indicate that polyglutamine proteins recruited into NIIs are not restricted to their expanded form. Among these proteins, recruitment of ataxin-2 was least frequent in every case examined, suggesting that the rate of recruitment partly depends on the protein transported into NIIs. Because other proteins lacking polyglutamine motif were not detected in NIIs, it is suggested that the presence of polyglutamine is a prerequisite for these proteins to be recruited into nucleus and to form NIIs. Interaction between expanded and non-expanded polyglutamine may play roles during these processes.

Preferential recruitment of ataxin-3 independent of expanded polyglutamine: an immunohistochemical study on Marinesco bodies.

In an immunohistochemical study of Marinesco bodies--a neuronal intranuclear inclusion often seen in neurons of the substantia nigra of patients with hepatic encephalopathy--it was shown that one of the polyglutamine proteins, ataxin-3, is preferentially recruited into this inclusion, whereas other polyglutamine proteins (ataxin-2 and TATA box-binding protein) are not. This suggests that recruitment of each of the polyglutamine proteins may be differently regulated. Because this nuclear inclusion is thought to be formed in response to cellular stress, as occurs in hepatic encephalopathy, even in the absence of an expanded CAG/polyglutamine repeat, recruitment of ataxin-3 and ubiquitin into Marinesco bodies may represent a cellular response to noxious external stimuli unrelated to expanded CAG/polyglutamine.

Evolution from pretangle neurons to neurofibrillary tangles monitored by thiazin red combined with Gallyas method and double immunofluorescence.

Double immunofluorescence for paired helical filament (PHF)-tau (AT8) and ubiquitin, enhanced by catalyzed reporter deposition amplification, was combined with thiazin red (TR), a fluorochrome, which has an affinity to fibrillary structures such as neurofibrillary tangles (NFTs). After recording these triple-fluorescent images, sections were subjected to the Gallyas silver impregnation method, so that four different staining properties could be compared on the same structure. Among pyramidal neurons quantified in the hippocampus from six cases of Alzheimer's disease, 60.3% were positive for ubiquitin, and were consistently positive for TR. TR-positive neurons (77.1%) harbored fibrillary structures in the cytoplasm and were always positive for the Gallyas stain, which stained the largest number of legions (94.5%). AT8-positive neurons without fibrillary structure were negative for TR (11.6%, pretangle neurons). Some of the pretangle neurons were positive for the Gallyas stain even without fibrillary structures. Appearance of TR stain and ubiquitin in NFTs, but not in pretangle neurons, suggests that ubiquitin is integrated into tau-positive neurons after their transformation into NFTs. Because TR-positive NFTs sometimes lacked ubiquitin-like immunoreactivity, involvement of ubiquitin may not be an early event during NFT formation. This combined method is now found useful in determining how molecules other than tau are involved during the evolution from tau-positive neurons to NFTs in various neurological disorders characterized by the deposition of tau.

SCA17, a novel autosomal dominant cerebellar ataxia caused by an expanded polyglutamine in TATA-binding protein.

Genetic etiologies of at least 20% of autosomal dominant cerebellar ataxias (ADCAs) have yet to be clarified. We identified a novel spinocerebellar ataxia (SCA) form in four Japanese pedigrees which is caused by an abnormal CAG expansion in the TATA-binding protein (TBP) gene, a general transcription initiation factor. Consequently, it has been added to the group of polyglutamine diseases. This abnormal expansion of glutamine tracts in TBP bears 47--55 repeats, whereas the normal repeat number ranges from 29 to 42. Immunocytochemical examination of a postmortem brain which carried 48 CAG repeats detected neuronal intranuclear inclusion bodies that stained with anti-ubiquitin antibody, anti-TBP antibody and with the 1C2 antibody that recognizes specifically expanded pathological polyglutamine tracts. We therefore propose that this new disease be called SCA17 (TBP disease).

Recruitment of nonexpanded polyglutamine proteins to intranuclear aggregates in neuronal intranuclear hyaline inclusion disease.

Recruitment of polyglutamine-containing proteins into nuclear inclusions (NIs) was investigated in neuronal intranuclear hyaline inclusion disease (NIHID). Some polyglutamine-containing proteins, ataxin-2, ataxin-3, and TATA box binding protein (TBP), as well as unidentified proteins with expanded polyglutamine tracts were recruited into NIs with different frequencies. Ataxin-3 was incorporated into most of the NIs and disappeared from its normal cytoplasmic localization, whereas only a small fraction of NIs contained ataxin-2 and TBP. The consistent presence of ataxin-3 in NIs could reflect a biological feature of wild-type ataxin-3, which is translocated into the nucleus under pathological conditions and participates in the formation of aggregates. Ataxin-2 also accumulated in the nucleus, but was not necessarily incorporated into NIs, suggesting that transport of these cytoplasmic proteins into the nucleus and their recruitment into NIs are not wholly explained by an interaction with a polyglutamine stretch and must be regulated in part by other mechanisms. The prevalence of ubiquitin-immunopositive NIs was inversely correlated to neuronal loss in all cases examined. This correlation could be explained if NI formation is a protective mechanism involving the ubiquitin-proteasome pathway. This hypothesis is supported by the finding that the polyglutamine epitope in the center of NIs was surrounded by ubiquitin.

Bunina body in frontal lobe dementia without clinical manifestations of motor neuron disease.

We report here an early autopsy case of a 60-year-old woman clinically diagnosed as having frontal lobe dementia without other neurological deficits. Postmortem examination revealed mild spongiosis in layers II and III of the frontal cortex, together with depletion of melanin-containing neurons in the substantia nigra. In addition to ubiquitin-positive neurites, ubiquitin-positive, tau-negative inclusions, which were previously considered to be a hallmark for motor neuron disease with or without dementia, were identified in neurons of the hippocampal dentate gyrus and of the temporal cortex. Although the patient lacked lower motor symptoms, the presence of Bunina bodies identified in the hypoglossal nuclei further supported the relationship of this case to motor neuron disease. Bunina bodies might be present in some cases of frontal lobe dementia. The presence or absence of Bunina bodies should be scrutinized even in cases without motor symptoms. In this case, creatine kinase of skeletal muscle origin was elevated, which might also be a potential indicator that suggests subclinical involvement of lower motor neurons.