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A research participant was monitored over nearly two decades at Mayo Clinic, undergoing annual neurologic assessments, neuropsychological tests, and multimodal imaging. Initially, he was cognitively normal but developed symptoms consistent with Posterior Cortical Atrophy (PCA) during the study. Early tests indicated mild, yet normal-range declines in language and visuospatial skills. FDG-PET scans revealed increased metabolism in posterior brain regions long before symptoms appeared. Advanced analysis using a novel in-house machine-learning tool predicted concurrent Alzheimer's disease and dementia with Lewy bodies. Autopsy confirmed a mixed neurodegenerative condition with significant Alzheimer's pathology and dense neocortical Lewy bodies. This case underscores the value of longitudinal imaging in predicting complex neurodegenerative diseases, offering vital insights into the early neurocognitive changes associated with PCA and dementia with Lewy bodies. [ABSTRACT FROM AUTHOR]

The basal forebrain cholinergic neurons (BFCN) provide the primary source of cholinergic innervation of the human cerebral cortex. They are involved in the cognitive processes of learning, memory, and attention. These neurons are differentially vulnerable in various neuropathologic entities that cause dementia. This review summarizes the relevance to BFCN of neuropathologic markers associated with dementias, including the plaques and tangles of Alzheimer's disease (AD), the Lewy bodies of diffuse Lewy body disease, the tauopathy of frontotemporal lobar degeneration (FTLD‐TAU) and the TDP‐43 proteinopathy of FTLD‐TDP. Each of these proteinopathies has a different relationship to BFCN and their corticofugal axons. Available evidence points to early and substantial degeneration of the BFCN in AD and diffuse Lewy body disease. In AD, the major neurodegenerative correlate is accumulation of phosphotau in neurofibrillary tangles. However, these neurons are less vulnerable to the tauopathy of FTLD. An intriguing finding is that the intracellular tau of AD causes destruction of the BFCN, whereas that of FTLD does not. This observation has profound implications for exploring the impact of different species of tauopathy on neuronal survival. The proteinopathy of FTLD‐TDP shows virtually no abnormal inclusions within the BFCN. Thus, the BFCN are highly vulnerable to the neurodegenerative effects of tauopathy in AD, resilient to the neurodegenerative effect of tauopathy in FTLD and apparently resistant to the emergence of proteinopathy in FTLD‐TDP and perhaps also in Pick's disease. Investigations are beginning to shed light on the potential mechanisms of this differential vulnerability and their implications for therapeutic intervention. [ABSTRACT FROM AUTHOR]

Abstract Diffuse Lewy body disease, also called dementia with Lewy bodies (DLB), is defined as progressive dementia and pathological Lewy bodies distributed in the central and autonomic nervous systems. The clinical features are dementia, cognitive fluctuations, visual hallucinations, parkinsonism, and REM sleep behavior disorder (RBD). Confirmatory techniques include dopamine transporter imaging, meta-iodobenzylguanidine (MIBG) myocardial scintigraphy, and polysomnography. The pathology finding in DLB is misfolded alpha-synuclein, the main component of Lewy bodies, propagating in the central nervous system. This may interrupt the acetylcholine pathway and activate an inflammatory response. Mutations of several genes have been found in patients with DLB, including SNCA , GBA , and APOE. The differential diagnosis of DLB and Parkinson's disease with dementia (PDD) is a debated issue. Clinical features distinguishing DLB from PDD include the timing of dementia and visual hallucinations, responses to dopaminergic agents and anti-psychotics, and imaging findings. As to the management of DLB, cholinesterase inhibitors are the Level-A recommendation for treating dementia in DLB patients and also are beneficial for treating visual hallucinations and psychotic symptoms. Dopamine agonists have the risk of inducing psychotic symptoms, while levodopa should be used carefully for motor symptoms. Melatonin and clonazepam are effective in controlling RBD. Several other treatment methods are undergoing trials, including pimavanserine, nilotinib, psychological interventions, and behavior therapy. Highlights • The fourth consensus report of the DLB Consortium consensus added REM sleep behavior disorder as the core feature. • Polysomnography finding is one of the indicative biomarkers. • Intercellular propagation of alpha-synuclein, microglial activation, and genes mutation are new findings of DLB pathology. • The features distinguish DLB from PDD are cognitive dysfunction and visual hallucination in early stage. • Cholinesterase inhibitors are the first line drugs to manage cognitive dysfunction and visual hallucination. • Antipsychiatry agents, dopamine agonists, and anticholinergics should be avoided because of neuropsychiatric side effects. [ABSTRACT FROM AUTHOR]

Single nucleotide polymorphisms in PICALM, a key component of clathrin-mediated endocytosis machinery, have been identified as genetic susceptibility loci for late onset Alzheimer's disease (LOAD). We previously reported that PICALM protein levels were decreased in AD brains and that PICALM was co-localised with neurofibrillary tangles in LOAD, familial AD with PSEN1 mutations and Down syndrome. In the present study, we analysed PICALM expression, cell localisation and association with pathological cellular inclusions in other tauopathies and in non-tau related neurodegenerative diseases. We observed that PICALM was associated with neuronal tau pathology in Pick disease and in progressive supranuclear palsy (PSP) and co-localised with both 3R and 4R tau positive inclusions unlike in corticobasal degeneration (CBD) or in frontotemporal lobar degeneration (FTLD)- MAPT P301L. PICALM immunoreactivities were not detected in tau-positive tufted astrocytes in PSP, astrocytic plaques in CBD, Lewy bodies in Lewy body disease, diffuse type (LBD) and in TDP-43-positive inclusions in FTLD. In the frontal cortex in tauopathies, the ratio of insoluble to soluble PICALM was increased while the level of soluble PICALM was decreased and was inversely correlated with the level of phosphotau. PICALM decrease was also significantly correlated with increased LC3-II and decreased Beclin-1 levels in tauopathies and in non-tau related neurodegenerative diseases. These results suggest that there is a close relationship between abnormal PICALM processing, tau pathology and impairment of autophagy in human neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

We proposed the term ' Lewy body disease' ( LBD) in 1980. Subsequently, we classified LBD into three types according to the distribution pattern of Lewy bodies: a brainstem type, a transitional type and a diffuse type. Later, we added the cerebral type. As we have proposed since 1980, LBD has recently been used as a generic term, including Parkinson's disease, Parkinson's disease with dementia and dementia with Lewy bodies. LBD has neuropathological characteristics whereby numerous Lewy bodies are present in the central and sympathetic nervous systems, and it is a type of alpha-synucleinopathy because the main component of Lewy body is alpha-synuclein. In this paper we explain the most recent concept of LBD from the historical viewpoint. [ABSTRACT FROM AUTHOR]

The accumulation of fibrillar α-synuclein protein is the pathological hallmark occurring in both multiple system atrophy (MSA) and diffuse Lewy body disease (DLBD). The oligodendrocytes are especially involved in MSA, while subtypes of neurons are the targets in DLBD. In both instances, the changes are widespread within the central nervous system, but with distinct and topistic vulnerability. Two diagnostic subtypes of MSA are currently applied: multiple system atrophy-cerebellar (MSA-C), formerly designated olivopontocerebellar atrophy, and multiple system atrophy-parkinsonian (MSA-P), formerly called striatonigral degeneration. However, overlaps exist between them, notably during the late stages of the illness. The brainstem and cerebellum are especially vulnerable and dysfunctional in MSA-C, but the striatum and mesencephalon in MSA-P, wherein parkinsonism usually prevails. In DLBD, Lewy-body-containing neurons (LBCN) involve the cerebral cortex in addition to the sites affected in Parkinson disease (PD). Thus, dementia and parkinsonism occur, often without brain atrophy. Then, two main pathological subtypes are used: the limbic or the cortical type. Possibly, DLBD, either the limbic or cortical-type, is the ultimate stage of PD, which corresponds to the brainstem type. The epidemiologic and genetic traits causing sporadic MSA and sporadic DLBD are not known. [ABSTRACT FROM AUTHOR]

Highlights: [•] Quantitative autoradiography of dopamine D1, D2, D3 receptors, VMAT2 and DAT. [•] Dopamine D2 and D3 receptor densities were measured using a novel procedure. [•] In Lewy body disease, D3 receptors were upregulated in the striatum. [ABSTRACT FROM AUTHOR]

We recently reported a missense mutation and four variants in eukaryotic translation initiation factor 4-gamma ( EIF4G1) associated with parkinsonism, dementia or both. In those with a positive family history, the mode of inheritance was autosomal dominant. Detailed neuropathologic descriptions of individuals with EIF4G1 genetic variants have not been reported. Herein, we report neuropathologic findings of three individuals from two American families with EIF4G1 variants. The patients had initial clinical presentations of dementia or parkinsonism and all had dementia at the time of autopsy. One family carried an EIF4G1 double variant, c.2056G>T (p.G686C) and c.3589C>T (p.R1197 W), and one family carried variant c.1505C>T (p.A502V). All three patients also carried at least one ε4 allele of apolipoprotein E. One individual presented with cognitive impairment without significant parkinsonism; one presented with memory problems followed by bradykinesia; and the third presented with cardinal signs of Parkinson's disease, followed more than a year later by cognitive dysfunction. Pathological examination showed diffuse cortical Lewy bodies and Lewy neurites in all patients. A small subset of Lewy bodies and Lewy neurites were immunopositive for eIF4G1. All patients had moderate to frequent non-neuritic, cortical amyloid plaques, mostly medial temporal neurofibrillary pathology (Braak neurofibrillary tangle stages of II to IV), and minimal or no TDP-43 pathology. The results suggest that in some patients variants in EIF4G1 can be associated with pathology that has a high likelihood of association with clinical features of dementia with Lewy bodies. [ABSTRACT FROM AUTHOR]

Abstract: Background: Heterozygous glucocerebrosidase (GBA) mutations are the leading genetic risk factor for Parkinson disease, yet imaging correlates, particularly transcranial sonography, have not been extensively described. Methods: To determine whether GBA mutation heterozygotes with Parkinson disease demonstrate hyperechogenicity of the substantia nigra, transcranial sonography was performed in Ashkenazi Jewish Parkinson disease subjects, tested for the eight most common Gaucher disease mutations and the LRRK2 G2019S mutation, and in controls. [18F]-fluorodeoxyglucose or [18F]-fluorodopa positron emission tomography is also reported from a subset of Parkinson disease subjects with heterozygous GBA mutations. Results: Parkinson disease subjects with heterozygous GBA mutations (n = 23) had a greater median maximal area of substantia nigral echogenicity compared to controls (n = 34, aSNmax = 0.30 vs. 0.18, p = 0.007). There was no difference in median maximal area of nigral echogenicity between Parkinson disease groups defined by GBA and LRRK2 genotype: GBA heterozygotes; GBA homozygotes/compound heterozygotes (n = 4, aSNmax = 0.27); subjects without LRRK2 or GBA mutations (n = 32, aSNmax = 0.27); LRRK2 heterozygotes/homozygotes without GBA mutations (n = 27, aSNmax = 0.28); and GBA heterozygotes/LRRK2 heterozygotes (n = 4, aSNmax = 0.32, overall p = 0.63). In secondary analyses among Parkinson disease subjects with GBA mutations, maximal area of nigral echogenicity did not differ based on GBA mutation severity or mutation number. [18F]-fluorodeoxyglucose (n = 3) and [18F]-fluorodopa (n = 2) positron emission tomography in Parkinson disease subjects with heterozygous GBA mutations was consistent with findings in idiopathic Parkinson disease. Conclusions: Both transcranial sonography and positron emission tomography are abnormal in GBA mutation associated Parkinson disease, similar to other Parkinson disease subjects. [Copyright &y& Elsevier]

Reticulons are a group of membrane-bound proteins involved in diverse cellular functions, and are suggested to act as inhibitors of β-secretase enzyme 1 (BACE1) activity that cleaves amyloid precursor protein. Reticulons are known to accumulate in the dystrophic neurites of Alzheimer's disease (AD), and studies have suggested that alterations in reticulons, such as increased aggregation, impair BACE1 binding, increasing amyloid-β production, and facilitating reticulon deposition in dystrophic neurites. To further characterize the cellular distribution of reticulon, we examined reticulon-3 expression in cases of AD, Parkinson's disease, and diffuse Lewy body disease. A more widespread cellular distribution of reticulon-3 was noted than in previous reports, including deposits in dystrophic neurites, neuropil threads, granulovacuolar degeneration, glial cells, morphologically normal neurons in both hippocampal pyramidal cell layer and cerebral neocortex, and specifically neurofibrillary tangles and Lewy bodies. These results are compatible with reticulon alterations as nonspecific downstream stress responses, consistent with its expression during periods of endoplasmic reticulum stress. This emphasizes the increasing recognition that much of the AD pathological spectrum represents a response to the disease rather than cause, and emphasizes the importance of examining upstream processes, such as oxidative stress, that have functional effects prior to the onset of structural alterations. [ABSTRACT FROM AUTHOR]

Visual complaints in patients with dementia are varied and attributable to both visual sensory (afferent) and ocular motor (efferent) dysfunction. This review focuses exclusively on the efferent visual dysfunction associated with dementia and aging. It provides a brief overview of the most common ocular motility disturbances associated with dementia, including Alzheimer’s disease, Parkinson’s disease, diffuse Lewy body disease, corticobasal syndrome, progressive supranuclear palsy, frontotemporal lobar degeneration, Creutzfeldt-Jakob disease, and others. An introduction to the six eye movement systems and the terminology associated with the evaluation of each system are reviewed. Assessment of efferent visual function in patients with dementia may be challenging, but familiarity with the potential pathologic eye movement findings in patients with dementia will allow for a focused assessment, diagnosis, and treatment when possible. [ABSTRACT FROM AUTHOR]

Abstract: Spongiform degeneration is characterized by vacuolation in nervous tissue accompanied by neuronal death and gliosis. Although spongiform degeneration is a hallmark of prion diseases, this pathology is also present in the brains of patients suffering from Alzheimer’s disease, diffuse Lewy body disease, human immunodeficiency virus (HIV) infection, and Canavan’s spongiform leukodystrophy. The shared outcome of spongiform degeneration in these diverse diseases suggests that common cellular mechanisms must underlie the processes of spongiform change and neurodegeneration in the central nervous system. Immunohistochemical analysis of brain tissues reveals increased ubiquitin immunoreactivity in and around areas of spongiform change, suggesting the involvement of ubiquitin–proteasome system dysfunction in the pathogenesis of spongiform neurodegeneration. The link between aberrant ubiquitination and spongiform neurodegeneration has been strengthened by the discovery that a null mutation in the E3 ubiquitin–protein ligase mahogunin ring finger-1 (Mgrn1) causes an autosomal recessively inherited form of spongiform neurodegeneration in animals. Recent studies have begun to suggest that abnormal ubiquitination may alter intracellular signaling and cell functions via proteasome-dependent and proteasome-independent mechanisms, leading to spongiform degeneration and neuronal cell death. Further elucidation of the pathogenic pathways involved in spongiform neurodegeneration should facilitate the development of novel rational therapies for treating prion diseases, HIV infection, and other spongiform degenerative disorders. [Copyright &y& Elsevier]

BACKGROUND AND PURPOSE To characterize the cerebral metabolic changes in dementia with Lewy bodies patients. METHODS The metabolic ratios of NAA/Cr and Cho/Cr in bilateral hippocampus were determined by proton magnetic resonance spectroscopy in 8 patients and 8 age-matched healthy controls. RESULTS Dementia with Lewy bodies patients showed significantly lower NAA/Cr ratios in bilateral hippocampus, while the Cho/Cr ratio did not differ from the control group. CONCLUSIONS Our data show relatively decrease of N-acetylaspartate in the hippocampus of patients with early or intermediate stage DLB. Hence, damage of neurons seems to be an early alteration in DLB. [ABSTRACT FROM AUTHOR]

Background: Nature of the dementing process in Parkinson's disease, and particularly its relationship with Alzheimer's disease, diffuse Lewy body disease or frontal dementia remains controversial. Objective: We hypothesize that origins of dementia in Parkinson's disease are heterogeneous, so we compared cortical regional cerebral blood flow (rCBF) between Parkinson's disease patients with and without dementia. Patients: Forty consecutive patients with Hoehn-Yahr stage III or IV Parkinson's disease were used (13 patients had dementia (PDD group), and 27 patients had no dementia (PDND group)). Results: There were significant rCBF reductions in the left parietal association cortex and left frontal association cortex in PDD. Multiple logistic regression analysis demonstrated that only rCBF of the left frontal association cortex was significant. PDD patients were divided into three groups according to rCBF patterns: frontal hypoperfusion group, Alzheimer's disease-like group, and diffuse Lewy body disease-like group. Conclusions: Controversial study results involving PDD patients may be mainly due to heterogeneity in dementing processes in Parkinson's disease. [ABSTRACT FROM AUTHOR]

Abstract: Vesicular monoamine transporter 2 (VMAT2) is responsible for packing dopamine into vesicles, and reduces the effects of neurotoxins by sequestering them into vesicles. In this report, we tested the hypothesis that VMAT2 is associated with Lewy body (LB) formation by immunohistochemical staining of midbrain and cortical sections of autopsied brains of patients with Parkinson''s disease (PD) and diffuse Lewy body disease (DLBD) for VMAT2 using a polyclonal antibody against VMAT2. LBs in the substantia nigra (SN) of PD and DLBD were immunoreactive for VMAT2, especially in the peripheral zone. Previous electron microscopic studies also revealed the presence of numerous dense core vesicles around the LBs, suggesting that these vesicles are related to LB formation. Indeed, the presence of a few vesicle-linked proteins such as synaptophysin and chromogranin A in LBs has been reported. Together with the low expression of VMAT2 in the SN of PD, the involvement of VMAT2 in LBs of the SN suggests the association of this protein in the neurodegeneration of nigral neurons in PD. [Copyright &y& Elsevier]

We report here a case of diffuse Lewy body disease with the A53T mutation in the α-synuclein gene. The proband presented at the age of 41 years with parkinsonism that was poorly responsive to levodopa. She subsequently developed cognitive impairment and moderate dementia, and died at the age of 50. Her father, paternal grandfather and uncle were all reported to have suffered from Parkinson’s disease. Staining of tissue sections from the proband’s brain with hematoxylin-eosin and α-synuclein antibodies showed small numbers of Lewy bodies in a few brain regions. This contrasted with large numbers of Lewy neurites and neuroaxonal spheroids in many brain regions. By electron microscopy, Lewy neurites consisted of abnormal filaments and dense granular material. Isolated filaments resembled those previously described in idiopathic Parkinson’s disease and dementia with Lewy bodies. They were decorated by antibodies specific for the N and C termini of α-synuclein, indicating the presence of the full-length protein. Nucleus accumbens and the lower layers in limbic areas of the cerebral cortex showed prominent vacuolation, with frequent clustering of microvacuoles around Lewy neurites. Nerve cell loss was most extensive in dorsal motor nucleus of the vagus nerve, substantia nigra and nucleus basalis of Meynert. Neurofibrillary tangles and senile plaques were not observed. However, in several brain regions, a few widely scattered tau-positive nerve cell bodies and neurites were present. By electron microscopy, Alzheimer-type paired helical and straight filaments were seen. [ABSTRACT FROM AUTHOR]

Background. Clinicopathological studies indicate that Alzheimer’s disease (AD) is the most common neurodegenerative cause of dementia, the other frequent causes are AD combined with diffuse Lewy bodies and dementia with Lewy bodies (DLB) by itself. When histological features of AD and DLB are found together in one brain we speak about Lewy body variant of AD (LBVAD). Beside global cognitive impairment LBVAD patients show signs of subcortical dementia and mild extrapiramidal signs.Methods and results. We present two patients with post-mortem diagnosis of LBVAD. Clinical and pathomorphological characteristics of the disease are discussed.Conclusions. Post-mortem studies show that LBVAD is the second most common cause of dementia, following AB.

Most clinicians and researchers still accept diffuse Lewy body disease (DLBD) as a clinicopathological entity. Dementia with fluctuating cognitive deficits, a parkinsonian syndrome, and visual hallucinations are the core symptoms of this proposed disease entity. From a neuropathological point of view, many examples of patients with progressive dementia showing evidence of extensive Lewy body formation in the cerebral cortex together with the occurrence of Lewy bodies in substantia nigra and locus coeruleus have been identified. Confusingly, a large majority of cases showing typical features of DLBD also present with an Alzheimer pathology in the hippocampus and cerebral cortex. It is far from clear that DLBD represents a specific disease entity rather an intermediate variant between Alzheimer disease and idiopathic parkinsonian syndromes. Nevertheless, from a clinical point of view it may be of importance to characterize patients with a symptomatology of DLBD because important management issues such as avoidance of severe neuroleptic sensitivity reactions, dopaminergic antiparkinsonian treatment and a beneficial response to cholinesterase inhibitors can be applied. [ABSTRACT FROM AUTHOR]

Diffuse Lewy body disease (DLBD) is characterized by the presence of Lewy bodies (LB) in the neurons and neurites of cortical, subcortical, and brain stem structures. Recently, α-synuclein (αS) has been found to be a central constituent of LB. In DLBD, abnormal accumulation of αS has been reported in both neurons and glia, but studies on glial lesions in DLBD have been limited. We examined in detail the constituents and distribution of glial lesions in eight patients with DLBD and report the pathogenesis of the glial lesions. αS-positive neuronal cytoplasmic inclusions (NI), neuropil threads (NT), and coiled bodies (CB) showed similar immunostaining profiles. Without pretreatment, NI, NT, and CB were detected by all antibodies against αS. The immunostaining profile of star-like astrocytes (SLA) was quite different from those of NI, NT, and CB. A few SLA were stained by an antibody against the non-Aβ component portion of αS without pretreatment, but formic acid pretreatment dramatically enhanced SLA immunoreactivity. SLA and CB were found in all eight brains with DLBD. SLA were scarce in the brain stem, but there were hundreds of SLA per visual field at ×100 magnification in the temporal cortex of most cases, while CB were found diffusely in both the cerebral cortex and brain stem, similar to NI. This suggests that the pathogenesis of SLA is different from those of NI and CB. [ABSTRACT FROM AUTHOR]

Proton magnetic resonance spectroscopy ([sup 1] H-MRS) provides a non-invasive, in vivo insight into the brain metabolism, and has been successfully used in several neurological conditions. Our objective was to characterise the cerebral metabolic changes in dementia with Lewy bodies (DLB) patients using [sup 1] H-MRS. Single Voxel [sup 1] H-MRS was performed in 12 DLB patients with mild to moderate symptoms and 11 age-matched healthy controls. Volumes of interest (VOI) were selected, including white matter (WM) in the centrum semiovale and grey matter (GM) in the parasagittal parietal cortex. Main metabolic peaks corresponding to N-acetylaspartate (NAA), glutamate/glutamine (Glx), choline-containing compounds (Cho), myo-inositol (Ins), and creatine plus phosphocreatine (Cr) were identified. These areas were measured and referred to that of the water. Metabolic ratios among the different peak areas were also calculated. In comparison with the control group, DLB patients showed significantly lower mean NAA/Cr, Glx1/Cr and Cho/Cr ratios in the WM, while their Ins/Cr and Ins/NAA ratios did not differ from those of the control group. In the GM, no significant differences were found between both groups. Correlations between age at onset, disease duration, Mini-Mental State Examination, the motor section of the Unified Parkinson’s Disease Rating Scale, Hoehn and Yahr staging and metabolic ratios, both for WM and GM, were not significant in DLB patients. Our spectroscopy data show WM involvement, along with GM preservation, in DLB patients with early or intermediate stages. Hence, [sup 1] H-MRS may provide adjunctive information in the ante-mortem diagnosis of DLB.Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Multiple lines of evidence indicate that oxidative stress is a critical pathogenic factor in Parkinson disease (PD) and diffuse Lewy body disease (DLBD). Previously, we demonstrated increased levels of redox-active iron in Lewy bodies, and that Lewy bodies accumulate advanced glycation end-products. To further characterize the role of oxidative stress in diseases with Lewy body formation, we examined immunocytochemically eight cases of PD and five cases of DLBD for adducts of the lipid peroxidation adduct 4-hydroxy-2-nonenal, and for Nε-(carboxymethyl)lysine (CML). Our findings demonstrate immunolocalization of 4-hydroxynonenal and CML to Lewy bodies in PD and DLBD. These findings not only support prior studies indicating that lipid peroxidation is increased in patients with PD and DLBD but that oxidative damage may play a critical role in Lewy body formation. [Copyright &y& Elsevier]

Diffuse Lewy body disease (DLBD) has been studied from various viewpoints and, although clinical diagnostic criteria for DLBD have been proposed, diagnosis remains difficult. DLBD has been reported to be the second most common form of dementia in the aged, following Alzheimer-type dementia. It has, however, been clinically under-diagnosed. Therefore, the search for diagnostic markers for DLBD must continue. Very recently, `dementia with Lewy bodies' (DLB) was proposed as a generic term for various forms of dementia with Lewy bodies, including DLBD and similar disorders. Cortical Lewy bodies are the most important pathologic marker for diagnosis of DLBD. At present, however, the mechanism responsible for cortical Lewy body formation has yet to be disclosed. [ABSTRACT FROM AUTHOR]

Central to the oxidative stress hypothesis of Parkinson’s disease (PD) pathogenesis is the ability of iron to generate hydroxyl radicals via the Fenton reaction, and the consistent demonstration of iron elevation in the pars compacta region of the substantia nigra. However, uncertainty exists as to whether the excess iron exists in a state suitable for redox chemistry. Here, using a method we developed that detects redox-active iron in situ, we were able to demonstrate strong labeling of Lewy bodies in substantia nigra pars compacta neurons in PD. In contrast, cortical Lewy bodies in cases of Lewy body variant of Alzheimer’s disease were unstained. While the presence of elevated iron in PD substantiates the oxidative stress hypothesis, one must remember that these are viable neurons, indicating that Lewy bodies may act to sequester iron in PD brains in a protective, rather than degenerative, mechanism. The absence of redox-active iron in neocortical Lewy bodies highlights a fundamental difference between cortical and brain stem Lewy bodies. [ABSTRACT FROM AUTHOR]