Gallyas-Braak Silver Staining Research Articles

Neuro-glial underpinning mechanisms in myelin plasticity for memory enhancement

Background and aim: Learning continually shapes our neuronal circuits to form new memories. Neural plasticity was considered as the principal mechanism for learning many decades ago. Although myelin was considered for a long time as static inert insulator, recent studies showed that myelination is dynamically changed to enhance neuronal activity under neural plasticity umbrella in terms of myelin plasticity, so our study aims to figure out the underlying mechanisms of myelin plasticity associated with learning and memory. Hypothesis: We hypothesized that many mechanisms promote memory consolidation by enhancing myelination and that glial cells have a crucial role in this myelin plasticity effect. Methods: The study was conducted on 24 rats, divided into 3 groups, with 8 rats in each; Group I (control); rats remained in their home cage, Group II (control untrained); rats were allowed to move and explore the maze for equal time but there was no active platform location learning, and Group III (trained); rats were trained using Barnez maze behavior test including three days of acquisition trials (AT), followed by two probe trials (PT). The gene expression analysis for SOX10, MYRF, NRG, EDGF, SERPINE2 and MBP was evaluated by qRT-PCR in hippocampus tissues, in addition, histopathological assessment was done with immunohistochemistry for Myelin Basic Protein (MBP), Glial Fibrillary Acidic Protein (GFAP), and Gallyas-Braak Silver staining. Furthermore, Pearson correlation was done comparing all genes with MBP expression. Results and data: The present study showed improved spatial memory with increased myelination in the trained group compared to all other groups (P<0.001), in addition to increase of SOX10, and MYRF expression in the trained group indicating more OPC differentiation into mature oligodendrocytes (P<0.001). NRG and EDGF were highly expressed in the trained group compared to other groups, in addition to the marked increase of number of the neuronal cells with more dendrites formation. SERPINE 2 and GFAP as markers of astrocytes showed high expression in the trained group in comparison with other groups (P<0.001) with strong positive correlation between SEPRINE 2 and MBP (r= 0.76, P=0.02). Conclusion: Myelin plasticity as one of the crucial learning mechanisms, was influenced by different neural and environmental signals. Although role of glial cells was almost apparent in oligodendrocytes differentiation and proliferation, there was a significant role of astrocytes in promoting such myelination effect. There were no external funding sources for this study, it is self-funding This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Argyrophilic grain disease is common in older adults and may be a risk factor for suicide: a study of Japanese forensic autopsy cases

BackgroundNeuropathological diagnosis of argyrophilic grain disease (AGD) is currently based primarily on the combination of argyrophilic grain (AG) visualized using Gallyas–Braak silver staining, phosphorylated tau-positive pretangles, coiled bodies, and ballooned neuron detection. Although AGD is common in patients with dementia and/or prominent psychiatric symptoms, whether it is a distinct neurological disease entity or a by-product of the aging process remains unclear.MethodsIn 1449 serial forensic autopsy cases > 40 years old (823 males and 525 females, aged 40–101 years, mean age 70.0 ± 14.1 years), we examined the frequency and comorbid pathology of AGD cases and investigated the clinical appearance by comparing those with non-AGD cases using the propensity score.ResultsOf the 1449 cases, we detected 342 AGD cases (23.6%; mean age 79.7 years; 177 males and 165 females). The AGD frequency and stage increased with age (P < 0.001). Among AGD cases, 80 (23.4%) patients had dementia, and 51 (15.2%) had a history of psychiatric hospital visits. The frequency of suicide and history of psychiatric disorders were significantly higher in AGD cases than in AGD-negative cases, matched for age, sex, and comorbidity pathology, with a relative risk of suicide of 1.72 (1.30–2.26). The frequency of suicide was significantly higher in AGD cases than in non-AGD cases in female but not male cases. The relative risk of suicide increased to 2.27 (1.20–4.30) and 6.50 (1.58–26.76) in AGD patients with Lewy and progressive supranuclear palsy pathology, respectively, and decreased to 0.88 (0.38–2.10) in those with advanced AD pathology. In AGD cases, 23.4% had dementia; however, the difference was not significant after controlling for age, sex, and comorbid pathology.ConclusionOur study demonstrated that AGD is a significant and isolated risk factor for psychiatric hospital visits and suicide completion. In older adults, AGs may contribute to the progression of functional impairment of the limbic system, which leads to psychiatric disorders and suicide attempts.

The protective effects of Esculentoside A through AMPK in the triple transgenic mouse model of Alzheimer's disease

BackgroundNeurofibrillary tangles comprising hyperphosphorylated tau are vital factors associated with the pathogenesis of Alzheimer's disease (AD). The elimination or reduction of hyperphosphorylated and abnormally aggregated tau is a valuable measure in AD therapy. Esculentoside A (EsA), isolated from Phytolacca esculenta, exhibits pharmacotherapeutic efficacy in mice with amyloid beta-induced AD. However, whether EsA affects tau pathology and its specific mechanism of action in AD mice remains unclear. PurposeTo investigate the roles and mechanisms of EsA in cognitive decline and tau pathology in a triple transgenic AD (3 × Tg-AD) mouse model. MethodsEsA (5 and 10 mg/kg) was administered via intraperitoneal injection to 8-month-old AD mice for eight consecutive weeks. Y-maze and novel object recognition tasks were used to evaluate the cognitive abilities of mice. Potential signaling pathways and targets in EsA-treated AD mice were assessed using quantitative proteomic analysis. The NFT levels and hippocampal synapse numbers were investigated using Gallyas-Braak silver staining and transmission electron microscopy, respectively. Western blotting and immunofluorescence assays were used to measure the expression of tau-associated proteins. ResultsEsA administration attenuated memory and recognition deficits and synaptic damage in AD mice. Isobaric tags for relative and absolute quantitation proteomic analysis of the mouse hippocampus revealed that EsA modulated the expression of some critical proteins, including brain-specific angiogenesis inhibitor 3, galectin-1, and Ras-related protein 24, whose biological roles are relevant to synaptic function and autophagy. Further research revealed that EsA upregulated AKT/GSK3β activity, in turn, inhibited tau hyperphosphorylation and promoted autophagy to clear abnormally phosphorylated tau. In hippocampus-derived primary neurons, inhibiting AMP-activated protein kinase (AMPK) activity through dorsomorphin could eliminate the effect of EsA, as revealed by increased tau hyperphosphorylation, downregulated activity AKT/GSK3β, and blocked autophagy. ConclusionsTo our knowledge, this study is the first to demonstrate that EsA attenuates cognitive decline by targeting the pathways of both tau hyperphosphorylation and autophagic clearance in an AMPK-dependent manner and it shows a high reference value in AD pharmacotherapy research.

An autopsied case of progressive supranuclear palsy presenting with cerebellar ataxia and severe cerebellar involvement

A Japanese male patient presented with gait disturbance at the age of 69 years. His principal symptom was cerebellar ataxia for several years. He was initially diagnosed as having olivopontocerebellar atrophy because dysarthria and ataxia gradually developed, and head CT scan showed apparent atrophy of the cerebellum and brainstem and dilatation of the fourth ventricle. Later, he showed vertical gaze palsy, dysphagia, retrocollis, parkinsonism, axial dominant rigidity and grasp reflex, and therefore, the diagnosis was modified to progressive supranuclear palsy (PSP). Progressive atrophy of the frontotemporal lobe, cerebellum and brainstem, and dilatation of the lateral, third and fourth ventricles were evident on MRI. Gastrostomy and tracheotomy were performed 9 and 10 years after onset, respectively, and the patient died after 11 years disease duration. At autopsy the brain weighed 1000 g and showed atrophy of the frontotemporal lobe, cerebellum and brainstem. Neurofibrillary tangles, mainly globose-type revealed by Gallyas-Braak silver staining, were extensively observed in the cerebral cortex and subcortical grey matter. Numerous glial fibrillary tangles, including tuft-shaped astrocytes and coiled bodies, and extensive argyrophilic threads were also recognized, particularly in the frontal lobe, basal ganglia, cerebellar white matter, brainstem and spinal cord. The Purkinje cell layer showed severe neuron loss with Bergmann's gliosis, and the dentate nucleus showed severe neuron loss with grumose degeneration. Tau-positive/Gallyas-positive inclusions in the Purkinje cells and the glial cells of the Purkinje cell layer were observed. Pathological findings of the present patient were consistent with the diagnosis of PSP, but the olivopontocerebellar involvement, particularly in the cerebellum, was generally more severe, and the quantity of tau-positive/Gallyas-positive structures were more abundant than in typical PSP cases. The existence of a distinct, rare PSP subtype with severe olivopontocerebellar involvement, "PSP-C", which tends to be clinically misdiagnosed as spinocerebellar degeneration in the early disease stage, is noteworthy. The present case corresponded to this rare subtype of PSP.

心筋へのMIBG集積低下をみとめ，交感神経節に限局するLewy小体を合併した大脳皮質基底核変性症の1剖検例

We report on an autopsy case of corticobasal degeneration (CBD) with Lewy bodies in only the sympathetic ganglia. A 79-year-old man showed walking disturbance as an initial symptom, and developed dementia and bradykinesia within the next 2 years. Neurological examination revealed parkinsonism-like akinesia and rigidity in the trunk and neck without resting tremor. Brain magnetic resonance imaging showed frontal lobe atrophy predominantly on the right side. Cardiac uptake of meta-iodobenzylguanidine (MIBG) was reduced (H/M ratio: 1.14). A diagnosis of dementia with Lewy bodies (DLB) was made, but L-dopa treatment was not effective. Seven years later he died of pneumonia. On pathological examination, the frontal cortex and white matter were degenerated, predominantly on the right side. Gallyas-Braak silver staining and AT-8 immunostaining revealed neurofibrillary tangles, pretangles, argyrophilic threads, and astrocytic plaques in the cerebral cortex and basal ganglia, confirming the diagnosis of CBD. Lewy bodies, which were not seen in the central nervous system, were seen only in the sympathetic ganglia, and a severe loss of nerve fibers was apparent in the sympathetic nerve endings in the heart. MIBG is currently used to differentiate DLB from other parkinsonisms, such as CBD, multiple system atrophy, and progressive supranuclear palsy, because reduced cardiac uptake of MIBG represents a pathological change in the sympathetic nerve endings in the heart. However, the distribution of Lewy bodies cannot be determined from this finding. Thus, MIBG should not be used alone to confirm a diagnosis of DLB; other neurodegenerative diseases with incidental Lewy body disease, as in the present case, must be also considered.

An autopsy case of diffuse neurofibrillary tangles with calcification: Early stage pathologic findings

A 66-year-old man with no medically remarkable past or family history gradually showed personality changes, memory disturbance, sleeplessness and abnormal behavior. Neurologic examination showed no focal signs and neither parkinsonism nor cerebellar ataxia was recognized. He died 4 years after the onset of dementia due to chronic renal failure. Neuropathologic examination revealed neuronal loss and gliosis in the temporal cortex, particularly in the subiculum, parahippocampal gyrus and entorhinal cortex, and insular cortex. NFTs were observed to be widespread in the cerebral cortex, especially the temporal cortex and brainstem, while senile plaques were not observed. Gallyas-Braak silver staining revealed the presence of numerous NFTs, glial inclusions and neuropil threads throughout the cerebral neocortex, limbic system, hippocampus and brainstem. The subiculum showed the most severe involvement; severe atrophy, severe neuron loss, and numerous ghost tangles (extracellular NFTs) were apparent. Although NFTs contained both monoclonal anti-3repeat-tau antibody (RD3) and RD4 immunoreactivity, this differed between the intracellular NFTs and ghost tangles. RD3 immunoreactivity was mainly observed in ghost tangles and neuropil threads, whereas RD4 immunoreactivity was mainly observed in intracellular NFTs and glial inclusions. Calcification was also found to be widespread in the cerebral cortex and white matter, basal ganglia, thalamus, cerebellar cortex, white matter and dentate nucleus. These characteristic neuropathologic findings lead to the pathologic diagnosis of diffuse neurofibrillary tangles with calcification (DNTC). It is argued that this patient showed early stage pathologic signs of DNTC due to a short disease duration, which may provide clues regarding the progression of this rare disease.

Tau protein aggregation in the frontal and entorhinal cortices as a function of aging

Objectives. 1 The abnormal accumulation of tau protein is increasingly recognized as the neuropathological hallmark of a number of dementing illness in which frontotemporal lobar degeneration occurs. In this paper we examined the age-dependant deposition of tau protein in the frontal and entorhinal neocortices. Methods. We examined autopsy records from 1997 to 2002 and selected 87 cases (10 in each decade from 0 to 79 years of age, 7 in 80–89 decade) with no history of dementia or other neurodegenerative diseases, and for which neurodegenerative diseases were excluded neuropathologically. Archival paraffin-embedded frontal and entorhinal cortices were examined by both Gallyas–Braak silver staining and a panel of antibodies recognizing tau protein accumulation. Results. Tau neuronal aggregates were observed in both frontal and entorhinal cortices in the third decade. While the frontal neuronal tau aggregates remained infrequent in the remaining decades, the number and extent of neuronal tau aggregates in the entorhinal cortex increased such that by the 7th decade the majority of cases showed extensive tau aggregate formation. The most consistent morphological observation was of dense, perikaryal neuronal tau-immunoreactive aggregates, similar to the total tau distribution, firstly presenting in cortical layers II and III and subsequently involving in layers IV–VI. Neuropil threads became maximal in the 9th decade in both frontal and entorhinal cortices. Astrocytic tau accumulation was first observed in both frontal and entorhinal cortices in the 6th decade, predominantly in layer I and subcortical white matter, and increased in number with aging. Extraneuronal tau reactive aggregates and coiled bodies were rarely observed in the entorhinal cortex, and when present, were scattered through layer II to VI. Conclusions. We have observed an age-dependant pattern of neuronal, extraneuronal and glial tau protein accumulation in the entorhinal cortex in individuals without neurodegenerative diseases. In contrast, tau protein aggregation is infrequently observed in the frontal cortex as a function of aging.

Pathologic diagnosis of non-Alzheimer type dementia

To characterize histopathologic features of non-Alzheimer type dementia. Bodian, Gallyas-Braak silver staining, tau and ubiquitin immunohistochemistry were applied in an analysis of 22 cases of autopsy-proven neurodegenerative dementia. Appearance, distribution and immunoreactivity of neuronal and glial inclusions in the brain were observed. The final histological diagnoses were made according to the pathological criteria for several types of common non-Alzheimer type dementia. Among the 22 cases of neurodegenerative dementia, 12 cases were identified as non-Alzheimer type dementia, including Pick's disease (2 cases), progressive supranuclear palsy (3 cases) and corticobasal degeneration (3 cases), dementia with Lewy bodies (1 case), and Parkinson's disease (3 cases). Another 10 cases consisted of pure Alzheimer's disease (AD, 9 cases) and AD combined with argyrophilic grain disease (1 case). Characteristic neuronal and glial inclusions, such as classical and cortical Lewy body, Pick body, Globous NFTs, astrocytic plaque and tufted astrocyte, argyrophilic grain were found in the brains of non-Alzheimer type dementia. Classical and cortical Lewy bodies were not argyrophilic but were immunoreactive to ubiquitin. Pick bodies, Globous NFTs, astrocytic plaques, tufted astrocytes and argyrophilic grains were all argyrophilic. Pick bodies showed tau and ubiquitin immunoreactivity. However, Globous NFTs, astrocytic plaques, tufted astrocytes, and argyrophilic grains were reactive only to tau immunohistochemistry. Findings of characteristic neuronal and glial inclusions may help to differentiate non-Alzheimer type dementia from AD, and in conjunction with Gallyas-Braak staining and immunohistochemistry for tau and ubiquitin, to further define histopathologic subcategories of non-Alzheimer type dementia.

Distribution of tuft-shaped astrocytes in the cerebral cortex in progressive supranuclear palsy.

The deposition of abnormal levels of tau protein is a major neuropathological feature of progressive supranuclear palsy (PSP), and the presence of tuft-shaped astrocytes is a neuropathological hallmark of PSP. We examined the topographic distribution of tuft-shaped astrocytes in the cerebral hemisphere by Gallyas-Braak silver staining in three Japanese autopsy cases of typical PSP. The distribution of tuft-shaped astrocytes was relatively uniform between cases. Tuft-shaped astrocytes were identified predominantly in posterior frontal areas such as the precentral gyrus and premotor and supplementary motor areas (Brodmann areas 4, 6 and 8). Tuft-shaped astrocytes were most dense in areas of cortical convexity, and they were more abundant in the crests of the cerebral gyri than in the valleys of the cerebral sulci. The temporal, parietal and occipital cortices, including the hippocampal formation and cingulate gyrus, were relatively free of tuft-shaped astrocytes. We confirmed involvement of the cerebral cortex in the pathology of PSP, and showed the widespread presence of tuft-shaped astrocytes, particularly in the precentral gyrus and premotor and supplementary motor areas, to be an essential neuropathological feature of PSP. The extra-pyramidal and pyramidal signs, supranuclear oculomotor abnormalities and other cortical signs associated with PSP may be related to the high density of tuft-shaped astrocytes in the precentral gyrus and premotor and supplementary motor areas. Dementia, apraxia, aphasia and frontal lobe signs may also result, at least in part, from this cortical involvement.

Tau accumulation in a patient with pallidonigroluysian atrophy

We studied the brain of a patient with pallidonigroluysian atrophy (PNLA) in whom argyrophilic and abnormally phosphorylated tau positive neurons and glia were identified in the brain on Gallyas–Braak silver staining and immunohistochemical analysis although neurofibrillary tangles were not seen by Bodian silver stain. Immunohistochemical studies using six anti-tau antibodies that recognize the different phosphorylated epitopes of tau protein revealed that these epitopes in neurons and glial cells share common characteristics with neurofibrillary tangles in Alzheimer's disease. Immunoblot analysis of phosphorylated tau protein showed major bands of 64 and 68 kDa and after dephosphorylation, tau consisted mainly of 4 repeat tau. No mutations were detected in the coding exons and their flanking intronic regions of the tau gene. This study suggests that PNLA is one of tauopathy and the biochemical characteristics of phosphorylated tau are similar to those found in progressive supranuclear palsy and corticobasal degeneration.

Astrocytic plaques and tufts of abnormal fibers do not coexist in corticobasal degeneration and progressive supranuclear palsy.

Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) are characterized by their unique clinical features and neuronal pathology. Although astrocytic plaques and tufts of abnormal fibers have been suggested to be specific histopathologic markers, recent studies have revealed significant clinicopathologic overlap between CBD and PSP. Based on the distinctive camera lucida profile of astrocytic inclusions on Gallyas-Braak silver staining, we found that astrocytic plaques and tufts of abnormal fibers did not coexist in the same patient among 30 cases of clinically diagnosed CBD, PSP and atypical Parkinson's disease. Using Tau immunohistochemistry it was difficult to verify the absence of tufts of abnormal fibers. A morphometric analysis revealed that the two groups classified by the presence or absence of astrocytic plaques and tufts of abnormal fibers exhibited significant differences in the density of ballooned neurons and neurofibrillary tangles and degeneration of the subcortical nuclei. Assessment using the NINDS neuropathologic criteria revealed that the cases with astrocytic plaques and tufts of abnormal fibers closely correspond to CBD and typical PSP, respectively. In addition, the cases lacking either of these two astrocytic inclusions had atypical PSP according to the NINDS criteria, and were associated with novel tau-positive astrocytes (spiny astrocytes). We thus conclude that astrocytic plaques and tufts of abnormal fibers are highly characteristic structures for CBD and typical PSP, respectively. We emphasize the importance of strict differentiation between different astrocytic inclusions not only for diagnosis, but also for further studies for elucidation of their role in the disease mechanisms of CBD and PSP.