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.     

Phosphorylated TDP-43 in Alzheimer’s disease and dementia with Lewy bodies

Phosphorylated and proteolytically cleaved TDP-43 is a major component of the ubiquitin-positive inclusions in the most common pathological subtype of frontotemporal lobar degeneration (FTLD-U). Intracellular accumulation of TDP-43 is observed in a subpopulation of patients with other dementia disorders, including Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB). However, the pathological significance of TDP-43 pathology in these disorders is unknown, since biochemical features of the TDP-43 accumulated in AD and DLB brains, especially its phosphorylation sites and pattern of fragmentation, are still unclear. To address these issues, we performed immunohistochemical and biochemical analyses of AD and DLB cases, using phosphorylation-dependent anti-TDP-43 antibodies. We found a higher frequency of pathological TDP-43 in AD (36–56%) and in DLB (53–60%) than previously reported. Of the TDP-43-positive cases, about 20–30% showed neocortical TDP-43 pathology resembling the FTLD-U subtype associated with progranulin gene (PGRN) mutations. Immunoblot analyses of the sarkosyl-insoluble fraction from cases with neocortical TDP-43 pathology showed intense staining of several low-molecular-weight bands, corresponding to C-terminal fragments of TDP-43. Interestingly, the band pattern of these C-terminal fragments in AD and DLB also corresponds to that previously observed in the FTLD-U subtype associated with PGRN mutations. These results suggest that the morphological and biochemical features of TDP-43 pathology are common between AD or DLB and a specific subtype of FTLD-U. There may be genetic factors, such as mutations or genetic variants of PGRN underlying the co-occurrence of abnormal deposition of TDP-43, tau and α-synuclein.     

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     

Lewy body-related α-synucleinopathy in the aged human brain

To clarify the significance of Lewy body (LB)-related alpha-synucleinopathy in aging and various neurodegenerative disorders, its incidence and topographic pattern were examined in 260 brains of elderly patients, including 116 autopsy-proven cases of Alzheimer disease (AD), 71 cases of clinically and autopsy-proven Parkinson disease (PD), 38 of dementia with Lewy bodies (DLB), 8 patients with progressive supranuclear palsy (PSP), one with senile tremor, and 26 age-matched controls without neuropsychiatric disorders. Using immunohistochemistry, alpha-synuclein (AS) positive lesions were assessed semiquantitatively. For technical reasons, the olfactory system was not systematically studied. All PD-brains showed AS-positive lesions in medullary, pontine and mesencephalic nuclei, with involvement of the nucleus basalis (90.1%), limbic cortex (58.9%), cingulate cortex (46%), amygdala, CA 2/3 hippocampal region (36.2%), neocortex (28.8%), and striatum (11%). 88% of clinical PD cases corresponded to LB pathology stages 4-6, 12% to stage 3 according to Braak et al. (2003). 84% of DLB brains were PD stage 5 or 6 and 17% stage 4, without significant differences between DLB with and without neuritic AD pathology, suggesting morphologic similarities betwee these disorders. 6/8 PSP and senile tremor cases, 49.1% of AD and 69% of aged controls were negative. AS-positive lesions in AD showed decreasing incidence from midbrain (24-28%), limbic cortex and amygdala (17-18%), nucleus basalis and medullary nuclei (13-17%), cingulate cortex (12%), CA 2/3 region (8%) to neocortex (2%), without gender differences or relationship to the severity of AD pathology (mean Braak stage 5.1). AD cases with AS positive lesions, particularly those with AS pathology in the amygdala, were older at death than negative ones (86.6 vs 83.3 yrs), but this difference was not statistically significant. 15 AD cases (seven of them with mild PD symptoms) and 3 aged controls without parkinsonian signs but LB pathology stages 3 (n=5) and 4 (n=13) were considered "incidental LB disease". 16 AD brains without parkinsonian symptoms had AS positive lesions in various areas without medullary involvement, suggesting deviation from the proposed stereotypic expansion pattern. Located AS-pathology in the midbrain and limbic cortex was seen in 31% of asymptomatic aged controls. These data 1. largely confirm Braak's staging of LB-pathology in PD; 2. suggest morphologic and pathogenic relations between PD (brainstem type) and DLB with and without coexistent AD pathology; 3. the occurrence of LB-related alpha-synucleinopathy in about 50% of AD brains and about 30% of aged controls. However, the basic mechanisms of LB-related AS-pathology and their pathogenic and clinical relevance in aged brain and neurodegenerative disorders await further elucidation.     

Prevalence and impact of vascular and Alzheimer pathologies in Lewy body disease

Whereas the prevalence and impact of vascular pathology in Alzheimer diease (AD) are well established, the role of vascular and Alzheimer pathologies in the progression of neurodegeneration and cognitive impairment in Parkinson disease (PD) is under discussion. A retrospective clinico-pathologic study of 100 patients with autopsy proven PD (including 44 cases with dementia/PDD) and 20 cases of dementia with Lewy bodies (DLB) confirmed essential clinical (duration of illness, Mini-Mental State Examination/MMSE, age at death) and morphologic differences between these groups; Lewy body Braak scores and Alzheimer pathologies (neuritic Braak stage, cortical Aβ plaque load, and generalized cerebral amyloid angiopathy or CAA) were significantly higher/more severe in DLB and PDD than in PD without dementia. Duration of illness showed no association to any of the examined pathologic parameters, while there was a moderate association between LB scores and neuritic Braak stages, the latter significantly increasing with age. Significant association between cerebrovascular lesions and neuritic Braak stage was seen in PDD but not in PD subjects without dementia. These data suggest an influence of Alzheimer-related lesions on the progression of the neurodegenerative process and, in particular, on cognitive decline in both PDD and DLB. On the other hand, both these factors in PD and DLB appear to be largely independent from coexistent vascular pathology, except in cases with severe cerebrovascular lesions or those related to neuritic AD pathology. Assessment of ApoE genotype in a small number of cases showed no significant differences in the severity of Aβ plaque load and CAA except for much lower intensities in non-demented ε3/3 patients. Despite increasing evidence suggesting synergistic reactions between α-synuclein (αSyn), tau and Aβ-peptides, the major protein markers of both AD and Lewy body diseases, and of both vascular pathology and AD, the molecular background and pathophysiological impact of these pathologies on the progression of neurodegeneration and development of cognitive decline in PD await further elucidation. Dedicated to the memory of Professor Dr. Franz Seitelberger, a pioneer of modern neuropathology and neurosciences.     

Cerebral amyloid angiopathy in Lewy body disease

Summary. While Alzheimer and Lewy body pathologies are discussed as major substrates of dementia in Parkinson’s disease (PD/Lewy body disease of brainstem type), the incidence and impact of cerebral amyloid angiopathy (CAA) and its association with cognitive decline in PD and dementia with Lewy bodies (DLB) are unknown. The severity of CAA and other Alzheimer lesions were assessed in 68 cases of autopsy-confirmed PD, 32 of them with dementia (PDD), and in 20 cases of DLB. PDD patients were significantly older than those without dementia (mean age 84.5 vs 77.6 years; p < 0.01), the age of DLB patients was in between both groups (mean 80.0 years), while duration of disease was DLB < PDD < PD (mean 6.5 vs 8.5 and 14.3 years). PDD patients had a significantly higher neuritic Braak stage (mean 4.2 vs 2.4, p < 0.01), significantly higher cortical amyloid β (Aβ) load, capillary cerebral amyloid angiopathy (CapCAA) and generalized CAA than those without dementia (mild CapCAA in 22% vs moderate to severe CapCAA in 87%; mild generalized CAA in 5.5% vs moderate to severe generalized CAA in 82%). Mean PD stage was higher in both DLB and PDD than in PD (mean 5.2 vs 4.5 and 4.0, respectively): Mean neuritic Braak stage in DLB was 3.4, severe Aβ plaque load was seen in 95%, moderate to severe CapCAA in 90% and mild to severe generalized CAA in 70%. This and other recent studies imply an association of CAA with cognitive decline in both PD/PDD and DLB, particularly in cases with concomitant AD-type pathology. Correspondence: Kurt A. Jellinger, Institute of Clinical Neurobiology, Kenyongasse 18, 1070 Vienna, Austria     

Braak's hypothesis and non-motor symptoms of Parkinson disease

In this review, we discuss dementia, depression, olfactory disturbance, sleep disorders and autonomic dysfunction as nonmotor symptoms of Parkinson disease (PD). PD with dementia (PDD) is defined as onset of dementia more than 1 year after the onset of parkinsonism. If dementia precedes or occurs less than 1 year after the onset of parkinsonism, a diagnosis of dementia with Lewy bodies (DLB) is made. There is essentially no difference in the pathology of PDD and DLB at autopsy, indicating that Braak's hypothesis, which is extracted from PD/PDD and excluding DLB, may be bias. REM-related behavioral disorder (RBD) or depression, the main locus of which is the brain stem, could precede or occur after the onset of PD or DLB, indicating a descending and ascending path of Lewy body (LB) pathology. A disturbance in olfaction usually precedes the onset of PD. Recent data indicate that severe olfactory dysfunction in PD is an indication of a high probability of mental decline. These clinical observations and our pathological reports support the presence of an olfactory-amygdala extension path of LB pathology in addition to Braak's hypothesis. Our pathological studies of consecutive autopsy cases showed that the involvement of autonomic ganglia was more frequent than that of the gastrointestinal tract, suggesting that initial the stage of LB pathology in Braak's hypothesis should be modified.     

Dementia with Lewy bodies and Parkinson's disease

Lewy bodies (LB) in the central nervous system are associated with several different clinical syndromes including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Long term follow up of PD patients finds up to 78% eventually develop dementia, most of these patients exhibiting fluctuating cognition and visual hallucinations similar to DLB and with extensive cortical LB at autopsy. alpha-Synuclein positive, neuritic pathology, in the putamen of DLB and Parkinson's disease dementia (PDD), may contribute to postural-instability gait difficulty, parkinsonism, diminished levodopa responsiveness and increased neuroleptic sensitivity. Cognitive and neuropsychiatric symptoms improve with cholinesterase inhibitor treatment in both patient groups. DLB and PDD should be seen as different points on a spectrum of LB disease. Distinguishing them as separate disorders may be useful in clinical practice, but may be of limited value in terms of investigating and treating the underlying neurobiology.     

Neuropathology of Parkinson's disease dementia and dementia with Lewy bodies with reference to striatal pathology

Dementia is relatively common in Parkinson's Disease (PD). When dementia occurs in the setting of PD, it is referred to as Parkinson's disease dementia (PDD), which is distinguished from the clinical syndrome in which dementia precedes extrapyramidal features, dementia with Lewy bodies (DLB). In this report, the neuropathology of PDD and DLB is reviewed and preliminary findings are reported on striatal pathology in 28 brains, including 7 PD, 7 PDD and 14 DLB. Sections of putamen immunostained for a-synuclein and investigated with image analysis show that striatal pathology is common and that both cortical and striatal a-synuclein pathology is greater in PDD and DLB than PD. Most cases of PDD and DLB have Alzheimer-type pathology, particularly amyloid plaques, which may act in an additive or synergistic manner with a-synuclein pathology. There are few pathologic differences between PDD and DLB, despite differences in their clinical course.     

β‐amyloid in lewy body disease is related to Alzheimer's disease‐like atrophy

The aim of this study was to investigate whether amyloid deposition is associated with Alzheimer's disease (AD)‐like cortical atrophy in Lewy body (LB) disease (LBD). Participants included 15 LBD with dementia patients (8 with dementia with Lewy bodies [DLB] and 7 with Parkinson's disease [PD] with dementia [PDD]), 13 AD patients, and 17 healthy controls. Age, gender, and Mini–Mental State Examination scores were matched between patient groups. All subjects underwent PET scans with [¹¹C]Pittsburgh Compound B to measure brain amyloid deposition as well as three‐dimensional T1‐weighted MRI. Gray‐matter volumes (GMVs) were estimated by voxel‐based morphometry. Volumes‐of‐interest analyses were also performed. Forty percent of the 15 DLB/PDD patients were amyloid positive, whereas all AD patients and none of the healthy controls were amyloid positive. Amyloid‐positive DLB/PDD and AD patients showed very similar patterns of cortical atrophy in the parahippocampal area and lateral temporal and parietal cortices, with 95.2% of cortical atrophy distribution being overlapped. In contrast, amyloid‐negative DLB/PDD patients had no significant cortical atrophy. Compared to healthy controls, parahippocampal GMVs were reduced by 26% in both the amyloid‐positive DLB/PDD and AD groups and by 10% in the amyloid‐negative DLB/PDD group. The results suggest that amyloid deposition is associated with AD‐like atrophy in DLB/PDD patients. Early intervention against amyloid may prevent or delay AD‐like atrophy in DLB/PDD patients with amyloid deposition. © 2012 Movement Disorder Society