Dementia with Lewy bodies: Reclassification of pathological subtypes and boundary with Parkinson's disease or Alzheimer's disease

The present study is an attempt to reclassify the pathological subtypes of DLB based on both Lewy pathology and Alzheimer pathology, and to clarify the pathological boundary between DLB and Parkinson's disease (PD) or Alzheimer's disease (AD) in autopsied cases, using pathological and immunohistochemical methods. Dementia with Lewy bodies was classified into the limbic type and neocortical type according to the degree of Lewy pathology, including Lewy bodies (LB) and LB‐related neurites, by our staging and was classified into the pure form, common form and AD form according to the degree of Alzheimer pathology including NFT and amyloid deposits by Braak staging. These combined subtypes were lined up on a spectrum not only with Lewy pathology but also with other DLB‐related pathologies including Alzheimer pathology, neuronal loss in the substantia nigra, spongiform change in the transentorhinal cortex and LB‐related neurites in the CA2‐3 region. There were some similarities in both Lewy pathology and other DLB‐related pathologies between PD and DLB, although Lewy pathology of PD was below the lowest stage of Lewy pathology. In contrast, AD did not meet the stages of Lewy pathology, and there were also no similarities in other DLB‐related pathologies between AD and DLB. In addition, LB of AD showed the characteristics different from those of DLB on the coexistence of LB with NFT. These present findings suggest that DLB has pathological continuity with PD, but can be pathologically differentiated from AD. The present study clarified the pathological entity of DLB, compared with PD and AD.     

Pathological entity of dementia with Lewy bodies and its differentiation from Alzheimer’s disease

We reclassified the pathological subtypes of dementia with Lewy bodies (DLB), based on both Lewy pathology and Alzheimer pathology, to clarify the pathological entity of DLB and the boundary between DLB and Alzheimers disease (AD) in autopsied cases, using both pathological and immunohistochemical methods. DLB was classified as either limbic type or neocortical type according to the degree of Lewy pathology including Lewy bodies (LB) and LB-related neurites by our staging, and was classified as pure form, common form or AD form according to the degree of Alzheimer pathology including neurofibrillary tangles (NFT) and amyloid deposits by Braak staging. These combined subtypes were lined up on a spectrum, not only with Lewy pathology but also with other DLB-related pathologies including Alzheimer pathology, neuronal loss in the substantia nigra, spongiform change in the transentorhinal cortex and LB-related neurites in the CA2–3 region. In contrast, the Lewy pathology of AD did not meet the stages of Lewy pathology in DLB, and there were scarcely any similarities in other DLB-related pathologies between AD and DLB. In addition, the Lewy pathology of AD had characteristics different from that of DLB, including the coexistence rate of LB with NFT, and the immunohistochemical and immunoelectron microscopic findings of LB and LB-related neurites. These findings suggest that DLB is a distinctive pathological entity that can be differentiated from AD, although it shows some pathological subtypes.     

Frequency and distribution of TUNEL‐positive neurons in brains of dementia with Lewy bodies: Comparison with those in brains of Alzheimer's disease

The present study investigated the frequency and distribution of TUNEL‐positive neurons in brains of dementia with Lewy bodies (DLB) in comparison with those in brains of Alzheimer's disease (AD), Down syndrome (DS) and non‐demented elderly persons. In DLB brains, TUNEL‐positive neurons were increased in frequency compared with those in non‐demented elderly brains, and showed a distribution similar to those in AD and DS brains. DLB cases with TUNEL‐positive neurons showing severe Lewy pathology were all neocortical type, while DLB cases of the limbic type showing mild Lewy pathology did not demonstrate TUNEL‐positive neurons. In addition, we investigated the relationships between TUNEL‐positive neurons and pathological hallmarks of DLB or AD brains. TUNEL‐positive neurons had no Lewy bodies or neurofibrillary tangles, and were not located within amyloid deposits. These findings suggest that neuronal damage showing DNA fragmentations occurs in DLB brains as well as in AD and DS brains, and that it is accelerated by progression of Lewy pathology as well as Alzheimer pathology, although it is not directly related to their pathological hallmarks.     

α-Synuclein pathology in Parkinson’s and Alzheimer’s disease brain: incidence and topographic distribution—a pilot study

To study the incidence and topographic distribution of α-synuclein-positive inclusions in Parkinson’s disease (PD), dementia with LB (DLB), and Alzheimer’s disease (AD), 206 brains of elderly patients, including 53 patients with clinical PD, 110 autopsy-proven AD cases, 22 with dementia with LB (DLB), 1 case with essential tremor, and 20 age-matched controls were investigated using α-synuclein immunohistochemistry. For technical reasons, the olfactory system was not studied. In all PD brains, α-synuclein-positive inclusions and neuronal losses were present in medullary and pontine nuclei, locus coeruleus, and substantia nigra, with additional lesions in amygdala (24%), allocortex (58%), cingulate area (34%), and isocortex (26.5%). All PD cases corresponded to pathology stage 4–6 suggested by Braak et al. (2003, Neurobiol Aging 24:197). In most cases of DLB, the distribution of α-synuclein pathology and neurodegeneration corresponded to stages 5 and 6 of PD pathology. The case with essential tremor and 48.2% of the AD cases showed no LB pathology; in the other AD brains α-synuclein-positive inclusions were seen in various brain areas. None of the controls showed LB pathology. Among 12 cases of incidental Lewy body disease (without clinical parkinsonian signs), 7 corresponded morphologically to PD stage 3 or 4. In further 6 AD cases, 2 with parkinsonian symptoms, considerable damage to locus coeruleus, substantia nigra, nucleus basalis and allocortex with preservation of the medullary nuclei was seen. The preliminary data largely confirm the Braak staging of brain pathology, although some of the clinical PD cases corresponded to stage 3 often considered as “preclinical”. In addition, some cases without demonstrable involvement of medullary nuclei showed extensive PD-like pathology in other brain areas, suggesting deviation from the proposed stereotypic expansion pattern and that incidental LB pathology may affect solely the locus coeruleus and substantia nigra. Striking similarity of LB pathology between DLB and PD suggests close morphological relationship between both disorders. Widespread LB lesions occurred in many sporadic AD cases without parkinsonian symptoms, the pathogenesis and clinical impact of which are unclear. The relationship between AD and PD with particular reference to synaptophysin-positive lesions needs further elucidation.     

Alpha-synuclein pathology in Parkinson's and Alzheimer's disease brain: incidence and topographic distribution--a pilot study

To study the incidence and topographic distribution of -synuclein-positive inclusions in Parkinsons disease (PD), dementia with LB (DLB), and Alzheimers disease (AD), 206 brains of elderly patients, including 53 patients with clinical PD, 110 autopsy-proven AD cases, 22 with dementia with LB (DLB), 1 case with essential tremor, and 20 age-matched controls were investigated using -synuclein immunohistochemistry. For technical reasons, the olfactory system was not studied. In all PD brains, -synuclein-positive inclusions and neuronal losses were present in medullary and pontine nuclei, locus coeruleus, and substantia nigra, with additional lesions in amygdala (24%), allocortex (58%), cingulate area (34%), and isocortex (26.5%). All PD cases corresponded to pathology stage 4–6 suggested by Braak et al. (2003, Neurobiol Aging 24:197). In most cases of DLB, the distribution of -synuclein pathology and neurodegeneration corresponded to stages 5 and 6 of PD pathology. The case with essential tremor and 48.2% of the AD cases showed no LB pathology; in the other AD brains -synuclein-positive inclusions were seen in various brain areas. None of the controls showed LB pathology. Among 12 cases of incidental Lewy body disease (without clinical parkinsonian signs), 7 corresponded morphologically to PD stage 3 or 4. In further 6 AD cases, 2 with parkinsonian symptoms, considerable damage to locus coeruleus, substantia nigra, nucleus basalis and allocortex with preservation of the medullary nuclei was seen. The preliminary data largely confirm the Braak staging of brain pathology, although some of the clinical PD cases corresponded to stage 3 often considered as preclinical. In addition, some cases without demonstrable involvement of medullary nuclei showed extensive PD-like pathology in other brain areas, suggesting deviation from the proposed stereotypic expansion pattern and that incidental LB pathology may affect solely the locus coeruleus and substantia nigra. Striking similarity of LB pathology between DLB and PD suggests close morphological relationship between both disorders. Widespread LB lesions occurred in many sporadic AD cases without parkinsonian symptoms, the pathogenesis and clinical impact of which are unclear. The relationship between AD and PD with particular reference to synaptophysin-positive lesions needs further elucidation.An erratum to this article can be found at     

Numerous and widespread α-synuclein-negative Lewy bodies in an asymptomatic patient

Lewy bodies (LB) and pale bodies (PB), their putative precursors, can be found in a spectrum of diseases characterized by parkinsonism and/or dementia. Furthermore, LB are occasionally observed in some other neurodegenerative diseases and in normal aging. Classical LB are typically found in the brain stem, especially in the substantia nigra, where these inclusions are associated with neuronal loss and clinical signs of idiopathic Parkinson’s disease (PD). The so-called cortical LB occur in the cerebral cortex, amygdala and claustrum with little or no neuronal loss and are clinically associated with dementia in dementia with LB (DLB). We describe a patient without apparent clinical signs of parkinsonism and/or dementia, whose brain contained numerous classical-like LB, pale inclusions with features of PB and transitions between these two. These inclusions had similar immunohistological (ubiquitin positive; neurofilament positive; tau negative) and ultrastructural features as the LB in PD and DLB except for the lack of immunoreactivity for α-synuclein. The pons and cerebral cortex showed the highest number of LB, up to 165/1.76 mm². These numbers were contrasted by the lack of obvious neuronal loss or gliosis. The absence of α-synuclein reactivity in the LB in this symptomless patient corroborates the hypothesis that α-synuclein accumulation in LB is an important step in neurodegeneration in PD and DLB, but tones down the role of α-synuclein in LB formation in general. This patient seems to represent a new variant in the spectrum of diseases associated with LB. Received: 28 May 1998 / Revised: 4 November 1998 / Accepted: 5 November 1998     

Clinical and quantitative pathologic correlates of dementia with Lewy bodies.

OBJECTIVES: To examine the distribution of cortical Lewy bodies (LB) and their contribution to the clinical syndrome in dementia with LB (DLB) and to address their relationship to the pathologic markers of AD and PD. METHODS: We studied 25 cases meeting neuropathologic criteria for DLB: 13 cases without AD (Braak stage I or II) and 12 cases with concomitant AD changes (Braak stages III to V). Age at onset, disease duration, and clinical symptoms were reviewed for each case. We quantified the regional distribution of LB in substantia nigra, paralimbic areas (cingulate gyrus, insula, entorhinal cortex, and hippocampus), and neocortex (frontal and occipital association areas) using anti-alpha-synuclein immunostaining. We compared the LB pathology between groups of patients with different symptoms at onset or with specific clinical phenotypes. RESULTS: There were no significant differences in clinical symptoms or LB density between cases with or without concomitant AD. LB density showed a consistent gradient as follows: substantia nigra > entorhinal cortex > cingulate gyrus > insula > frontal cortex > hippocampus > occipital cortex. LB density in substantia nigra and neocortex was not significantly different in cases that started with parkinsonism compared with those that started with dementia. There were no significant differences in LB density in any region among patients with or without cognitive fluctuations, visual hallucinations, delusions, recurrent falls, or parkinsonism. Duration of the disease correlated with a global LB burden for each case (p = 0.02) but did not correlate with LB density in any individual area. Paralimbic and neocortical LB density were highly correlated with each other (p<0.0001), but neither of these correlated well with the number of LB in substantia nigra. LB density did not correlate with Braak stage or frequency of neuritic plaques. CONCLUSIONS: There is a consistent pattern of vulnerability to LB formation across subcortical, paralimbic, and neocortical structures that is similar for DLB cases with or without concomitant AD. Paralimbic and neocortical LB do not correlate with LB in substantia nigra, suggesting that DLB should not be considered just a severe form of PD. LB density correlates weakly with clinical symptoms and disease duration.     

Non‐uniformity in the regional pattern of Lewy pathology in brains of dementia with Lewy bodies

We examined the regional pattern of Lewy pathology in brains of dementia with Lewy bodies (DLB) to clarify whether Lewy pathology uniformly progresses or not. Thirty‐five autopsied DLB cases were examined using α‐synuclein‐immunohistochemistry, and the regional degree of Lewy pathology in the brainstem, diencephalon and cerebral cortex was quantitatively evaluated. Consequently, we found that the regional pattern of Lewy pathology differed according to the pathological subtype, and was divided into three types: type 1 showed a brainstem‐predominant pattern, type 2 was almost equal for the brainstem and cerebral cortex, and type 3 showed a cerebral cortex‐predominant pattern. The limbic type/pure and common forms were mainly composed of type 1, whereas the neocortical type/common and Alzheimer's disease (AD) forms were mainly composed of type 3. These findings suggest the possibility that Lewy pathology of the limbic type/pure and common forms mainly progresses from the brainstem to the cerebrum, whereas that of the neocortical type/common and AD forms mainly progresses from the cerebrum to the brainstem. Cases with type 1 Lewy pathology mainly developed parkinsonism, whereas those with type 3 Lewy pathology mainly developed dementia. This corresponded to most of the limbic type/pure and common forms which developed parkinsonism, whereas most of the neocortical type/common and AD forms developed dementia. Type 1 cases may thus be clinically diagnosed as having Parkinson's disease (PD) with dementia. These findings suggest that PD has clinico‐pathological continuity with DLB, and that the regional pattern of Lewy pathology is not uniform.     

Neuronal hemoglobin is reduced in Alzheimer's disease, argyrophilic grain disease, Parkinson's disease, and dementia with Lewy bodies

Previous studies have demonstrated the presence of hemoglobin α-chain and β-chain in neurons of the rodent and human brain thus indicating that hemoglobin is a normal component of nerve cells and that hemoglobin may play a role in intraneuronal oxygen homeostasis. Progressing with these studies, hemoglobin expression has been examined in selected cell population in the brains of Alzheimer's disease (AD), argyrophilic grain disease (AGD), Parkinson's disease (PD) and Dementia with Lewy bodies (DLB). Double labeling immunofluorescence and confocal microscopy revealed reduced hemoglobin α-chain and β-chain in practically all neurons with small amounts of granular or punctuate hyperphosphorylated tau deposits and in neurons with tangles in the hippocampus and frontal cortex in AD and in the hippocampus in AGD; in ballooned neurons containing αB-crystallin in the amygdala in AD and AGD; and in about 80% of neurons with punctuate α-synuclein deposits and in neurons with Lewy bodies in the substantia nigra pars compacta and in vulnerable neurons of the medulla oblongata in PD and DLB; and in neurons with Lewy bodies in the frontal cortex in DLB. Hemoglobin immunoreactivity was also observed in the core of neuritic plaques and in diffuse plaques, but not in dystrophic neurites. Loss of hemoglobin was specific as neuroglobin was present equally in neurons with and without abnormal protein inclusions, and erythropoietin receptor was expressed equally in neurons without and in neurons with abnormal protein aggregates in AD, AGD, PD, and DLB.     

Lewy body pathology in Alzheimer’s disease

Lewy bodies, the characteristic pathological lesion of substantia nigra neurons in Parkinson's disease (PD), are frequently observed to accompany the amyloid plaque and neurofibrillary tangle pathology of Alzheimer's disease (AD). However the typical anatomic distribution of Lewy bodies in AD is distinct from PD. The most common site of occurrence is the amygdala, where Lewy bodies are observed in approximately 60% of both sporadic and familial AD. Other common sites of occurrence include the periamygdaloid and entorhinal cortex, while neocortical and brainstem areas develop Lewy bodies in a lower percentage of cases. In contrast, dementia with Lewy bodies (DLB), defined by widespread neocortical and brainstem Lewy bodies but frequently accompanied by variable levels of AD-type pathology, represents the other end of a spectrum of pathology associated with dementia. The observation of Lewy bodies in familial AD cases suggests that like neurofibrillary tangles, the formation of Lewy bodies can be induced by the pathological state caused by Abeta-amyloid overproduction. The role of Lewy body formation in the dysfunction and degeneration of neurons remains unclear. The protein alpha-synuclein appears to be an important structural component of Lewy bodies, an observation spurred by the discovery of point mutations in the alpha-synuclein gene linked to rare cases of autosomal dominant PD. Further investigation of alpha-synuclein and its relationship to pathological conditions promoting Lewy body formation in AD, PD, and DLB may yield further insight into pathogenesis of these diseases.     

Multiple organ involvement by alpha‐synuclein pathology in Lewy body disorders

Lewy body (LB) diseases are characterized by alpha‐synuclein (AS) aggregates in the central nervous system (CNS). Involvement of the peripheral autonomic nervous system (pANS) is increasingly recognized, although less studied. The aim of this study was to systematically analyze the distribution and severity of AS pathology in the CNS and pANS. Detailed postmortem histopathological study of brain and peripheral tissues from 28 brain bank donors (10 with Parkinson's disease [PD], 5 with dementia with LB [DLB], and 13 with non‐LB diseases including atypical parkinsonism and non‐LB dementia). AS aggregates were found in the pANS of all 15 LB disease cases (PD, DLB) in stellate and sympathetic ganglia (100%), vagus nerve (86.7%), gastrointestinal tract (86.7%), adrenal gland and/or surrounding fat (53.3%), heart (100%), and genitourinary tract (13.3%), as well as in 1 case of incidental Lewy body disease (iLBD). A craniocaudal gradient of AS burden in sympathetic chain and gastrointestinal tract was observed. DLB cases showed higher amounts of CNS AS aggregates than PD cases, but this was not the case in the pANS. No pANS AS aggregates were detected in Alzheimer's disease (AD) cases with or without CNS AS aggregates. All pathologically confirmed LB disease cases including 1 case of iLBD had AS aggregates in the pANS with a craniocaudal gradient of pathology burden in sympathetic chain and gastrointestinal tract. AS was not detected in the pANS of any AD case. These findings may help in the search of peripheral AS aggregates in vivo for the early diagnosis of PD. © 2014 International Parkinson and Movement Disorder Society     

Clinicopathological multiplicity of dementia with Lewy bodies

‘Dementia with Lewy bodies (DLB)’ is a generic clinicopathological concept characterized by progressive dementia and Lewy bodies (LB). We examined 23 autopsied DLB cases clinicopathologically and immunohistochemically. These cases were classified into the neocortical type (10 cases), the limbic type (seven cases), the cerebral type (one case) and the brainstem type (none) according to our pathological criteria, which were based on the regional incidence of LB and the degree of neuronal loss in the substantia nigra. Each subtype of DLB was further divided into the common form and the pure form on the basis of the degree of Alzheimer pathology. The remaining five cases were not classified by our pathological criteria, and were designated ‘the senile dementia of Alzheimer type (SDAT) or Alzheimer's disease (AD) type of DLB with neocortical or limbic LB’. We examined how each subtype was correlated with various clinical features, such as the age of disease onset, the clinical duration, the degree of dementia, and the presence or absence of parkinsonism, fluctuating cognition and visual hallucination. The results of this study indicate that DLB can be clinicopathologically divided into a number of subtypes, that each subtype is preferentially correlated with some clinical feature, and that the neocortical type, common form, is the major type of DLB.     

Activated microglial cells and complement factors are unrelated to cortical Lewy bodies

Inflammatory mechanisms have been demonstrated in Alzheimer’s disease (AD) but their presence in other neurodegenerative disorders is not well documented. Complement factors and activated microglia have been reported in the substantia nigra of Parkinson’s disease (PD). In the present study we investigated the cingulate gyrus of 25 autopsied patients with clinically and neuropathologically well-documented PD, with or without dementia, for the presence of (activated) microglial cells and their relation with Lewy body (LB)-bearing neurons. In addition, we studied the presence of complement factors in LBs. Of the 25 patient, 15 were clinically demented, fulfilling criteria for dementia with LBs (DLB); 7 also fulfilled CERAD morphological criteria for probable or definite Alzheimer type of dementia. Microglia clustering was seen around congophilic plaques with or without tau pathology. Microglial cells were not associated with LB-bearing neurons or noncongophilic plaques. The cortex of DLB patients without AD plaques did not show more microglial cells than the cortex of non-demented controls. The number of microglia was the lowest in young control patients who died immediately after trauma. Complement factor C3d was occasionally seen in diffusely ubiquinated neurons but late complement factors were not detected in these neurons. Double staining for complement and α-synuclein was negative, suggesting the absence of complement in LBs. In contrast, AD plaques in the same sections showed complement factors C3c, C3d, C1q and C5–9. In conclusion, we have found no evidence that inflammatory mechanism are involved in LB formation in cerebral cortex. Received: 17 June 1999 / Revised: 20 December 1999 / Accepted: 15 February 2000     

Parkinson's disease and dementia with Lewy bodies: One disease or two?

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) have clinical features in common and are both characterized neuropathologically by the presence of Lewy bodies (LBs). We conducted a clinicopathological correlation pilot study to better understand whether PD and DLB represent two distinct nosological entities or rather exist along the spectrum of a single LB disease. A neuropathologist blinded to clinical diagnoses evaluated brains with largely pure LB pathology to determine LB distribution and frequency. Research clinicians blinded to LB distribution and frequency determined consensus clinical diagnoses. Clinical features separated cases into two groups, one having features most compatible with PD and the other with DLB. The groups were distinguishable mainly by the time course of clinical symptoms. Although the presence of neocortical LBs was more common in the group of patients with clinical features of DLB, neocortical LBs were also present in 1 member of the PD group and even in the clinically normal control subject. Thus, there appear to be two clinical syndromes, distinguished mainly by the time course of symptoms. The mechanisms responsible for the different clinical presentations are not known, and the issue of whether PD and DLB represent two distinct diseases remains unsettled.     

Progressive aphasia with Lewy bodies

Dementia with Lewy bodies (DLB) may include both Alzheimer and Lewy body pathology, but has never been reported to cause primary progressive aphasia. We report a 69-year-old woman who died 11 years after presenting with the syndrome of progressive aphasia. Six years after aphasia onset she developed visual hallucinations, and subsequently parkinsonism. Autopsy examination revealed Alzheimer's disease (AD), cortical Lewy bodies, and depigmentation and Lewy bodies in the substantia nigra and locus ceruleus. The aphasia most likely reflected the initial onset of AD, and the psychosis and parkinsonism most likely reflected the subsequent onset of Lewy body pathology. This first reported case of progressive aphasia occurring within the context of AD and Lewy body pathology uniquely illustrates the clinical and pathological nosological relationships between these two disease processes, and demonstrates a limitation of the general term, 'DLB'.     

An atypical autopsy case of Lewy Body disease with clinically diagnosed major depression: A clinical,radiological and pathological study

We report an 84‐year‐old woman who was clinically diagnosed with late‐life major depression (LLMD) and having a diffuse type of dementia with Lewy bodies (DLB) neuropathologically. Clinically, this case showed depressive mood, anxiety, and irritation, but did not show cognitive dysfunction, visual hallucination, fluctuation of alertness and parkinsonism, which define the criteria for diagnosing DLB. Neuropathological examination demonstrated abundant Lewy‐related pathology including Lewy bodies and neurites in the hippocampal region and the cerebral cortex, and moderate levels in brain stem nuclei including the substantia nigra, locus ceruleus and dorsal raphe nucleus. These findings suggest the possibility that Lewy‐related pathology is associated with the depressive symptoms. Furthermore, it must be noted that some patients diagnosed with LLMD clinically may develop pathology of DLB without the typical or usual clinical symptoms.     

Neuropathological correlates to clinically defined dementia with Lewy bodies

OBJECTIVES: To analyse the neuropathological changes behind clinically defined dementia with Lewy bodies (clinDLB) compared with clinically diagnosed Alzheimer's disease (clinAD). METHODS: The prevalence of neuropathological findings in 48 clinDLB and 45 clinAD cases was compared. Sixteen clinDLB and 10 clinAD cases were reassessed with alpha-synuclein staining for Lewy bodies (LB). RESULTS: Alzheimer pathology was found in 81% of the clinDLB and 93% of the clinAD cases. The clinDLB group had a higher prevalence of frontal white matter pathology, mostly of ischemic type, and a more severe degeneration of the substantia nigra compared with the clinAD group. In hematoxylin-eosin staining, LBs were identified in seven (15%) of the clinDLB and in four (9%) of the clinAD group. In alpha-synuclein staining, 38% of the clinDLB and 40% of the clinAD cases exhibited LBs. The cases without LBs, in the clinDLB group, had AD pathology in combination with frontal white matter disease. Vascular pathology of significant degree was prevalent in more than 40% of all the cases with verified LBs regardless of clinical diagnosis. CONCLUSION: Consecutive dementia cases, fulfilling the clinical consensus criteria for DLB, may exhibit combinations of neuropathological changes which in themselves can explain the clinical picture of DLB even when LBs are absent.     

Immunohistochemical study of the expression of cytokines and nitric oxide synthases in brains of patients with dementia with Lewy bodies

Regional expression of cytokines (IL‐1α, TNF‐α), inducible nitric oxide synthase (iNOS) and neuronal NOS (nNOS) was immunohistochemically investigated in the brains of patients with dementia with Lewy bodies (DLB), compared with those of patients with Alzheimer's disease (AD) and non‐demented elderly persons. It has been reported that inflammatory responses by cytokines and oxygen free radicals such as nitric oxide (NO) are associated with damaged neurons, degenerative neurites or amyloid deposits in AD brains. In the present study, overexpression of IL‐1α, TNF‐α and iNOS was demonstrated in the amygdala, hippocampus, entorhinal and insular cortices of DLB brains, which are pathologically the most vulnerable regions in DLB brains as well as AD brains. In addition, some Lewy body (LB)‐bearing neurons were involved by the processes of IL‐1α‐ and TNF‐α‐positive microglia, and most extracellular LB were associated with the processes of TNF‐α‐ and iNOS‐positive astroglia. Glial involvement was also found around neuritic plaques and extracellular neurofibrillary tangles. In contrast, the expression of nNOS was reduced in the amygdala of DLB brains showing severe Lewy pathology. These findings suggest that cytokines and NO are significantly implicated in neuronal damage and death including LB formation in DLB brains.     

Comparison of dementia with Lewy bodies to Alzheimer's disease and Parkinson's disease with dementia.

We compared the clinical and neuropsychological pattern of dementia with Lewy bodies (DLB) to Alzheimer's disease (AD) and Parkinson's disease with dementia (PD-d). Sixteen patients clinically diagnosed with DLB were compared with two groups of patients with PD-d (n = 15) and AD (n = 16) matched for level of dementia. Isolated cognitive impairment was the most common form of presentation in AD (93.8%) and DLB (31.3%) groups, while parkinsonism was in 100% of PD-d subjects. Psychoses associated with cognitive impairment at the beginning of the disease were more frequent in DLB patients (31.3%) than in AD (6.3%) and PD-d (0%) groups. There were no significant differences in Unified Parkinson Disease Rating Scale motor-subscale scores between DLB and PD-d patients. DLB and PD-d patients performed significantly worse on attentional functions and better on memory tests than AD. DLB patients also showed lower scores than AD subjects on visual memory, visuoperceptive, and visuoconstructive tests. No significant differences were found between PD-d group and DLB subjects on any neuropsychological test. We were unable to find any differences in cognitive tasks between PD-d and DLB subjects. Clinical features and neuropsychological deficiencies of DLB (attentional, visuoperceptive, and visuoconstructive deficits) and PD (attentional deficits) compared to AD (amnesic syndrome) can contribute to accurate identification of these entities and to the understanding of the neuropathological and neurochemical substrate underlying these diseases.     

Association of olfactory dysfunction with incidental Lewy bodies.

Olfactory dysfunction is found in early Parkinson's disease (PD) and in asymptomatic relatives of PD patients. Incidental Lewy bodies (ILB), the presence of Lewy bodies in the brains of deceased individuals without a history of PD or dementia during life, are thought to represent a presymptomatic stage of PD. If olfactory dysfunction were associated with the presence of ILB, this would suggest that olfactory deficits may precede clinical PD. The purpose of this study was to determine the association of olfactory dysfunction during late life with ILB in the substantia nigra or locus ceruleus. Olfaction was assessed during the 1991-1994 and 1994-1996 examinations of elderly Japanese-American men participating in the longitudinal Honolulu-Asia Aging Study. Among those who later died and underwent a standardized postmortem examination, brains were examined for Lewy bodies in the substantia nigra and the locus ceruleus with hematoxylin and eosin stain. Lewy bodies in the brains of individuals without clinical PD or dementia were classified as ILB. There were 164 autopsied men without clinical PD or dementia who had olfaction testing during one of the examinations. Seventeen had ILB. The age-adjusted percent of brains with ILB increased from 1.8% in the highest tertile of odor identification to 11.9% in the mid-tertile to 17.4% in the lowest tertile (P = 0.019 in test for trend). Age-adjusted relative odds of ILB for the lowest versus the highest tertile was 11.0 (P = 0.02). Olfactory dysfunction is associated with ILB. If incidental Lewy bodies represent presymptomatic stage of PD, olfactory testing may be a useful screening tool to identify those at high risk for developing PD.