A versatile fluorescence-quenched substrate for quantitative measurement of glucocerebrosidase activity within live cells.

Loss of activity of the lysosomal glycosidase ß-glucocerebrosidase (GCase) causes the lysosomal storage disease Gaucher disease (GD) and has emerged as the greatest genetic risk factor for the development of both Parkinson disease (PD) and dementia with Lewy bodies. There is significant interest into how GCase dysfunction contributes to these diseases, however, progress toward a full understanding is complicated by presence of endogenous cellular factors that influence lysosomal GCase activity. Indeed, such factors are thought to contribute to the high degree of variable penetrance of GBA mutations among patients. Robust methods to quantitatively measure GCase activity within lysosomes are therefore needed to advance research in this area, as well as to develop clinical assays to monitor disease progression and assess GCase-directed therapeutics. Here, we report a selective fluorescence-quenched substrate, LysoFQ-GBA, which enables measuring endogenous levels of lysosomal GCase activity within living cells. LysoFQ-GBA is a sensitive tool for studying chemical or genetic perturbations of GCase activity using either fluorescence microscopy or flow cytometry. We validate the quantitative nature of measurements made with LysoFQ-GBA using various cell types and demonstrate that it accurately reports on both target engagement by GCase inhibitors and the GBA allele status of cells. Furthermore, through comparisons of GD, PD, and control patient-derived tissues, we show there is a close correlation in the lysosomal GCase activity within monocytes, neuronal progenitor cells, and neurons. Accordingly, analysis of clinical blood samples using LysoFQ-GBA may provide a surrogate marker of lysosomal GCase activity in neuronal tissue.

Endothelin-converting enzymes degrade α-synuclein and are reduced in dementia with Lewy bodies.

We have examined the roles of the endothelin-converting enzyme-1 and -2 (ECE-1 and ECE-2) in the homeostasis of α-synuclein (α-syn) and pathogenesis of Lewy body disease. The ECEs are named for their ability to convert inactive big endothelin to the vasoactive peptide endothelin-1 (EDN1). We have found that ECE-1 and ECE-2 cleave and degrade α-syn in vitro and siRNA-mediated knockdown of ECE-1 and ECE-2 in SH-SY5Y neuroblastoma cells significantly increased α-syn both intracellularly (within the cell lysate) (p < 0.05 for both ECE-1 and -2) and extracellularly (in the surrounding medium) (p < 0.05 for ECE-1 and p = 0.07 for ECE-2). Double immunofluorescent labelling showed co-localization of ECE-1 and ECE-2 with α-syn within the endolysosomal system (confirmed by a proximity ligation assay). To assess the possible relevance of these findings to human Lewy body disease, we measured ECE-1 and ECE-2 levels by sandwich ELISA in post-mortem samples of cingulate cortex (a region with a predilection for Lewy body pathology) in dementia with Lewy bodies (DLB) and age-matched controls. ECE-1 (p < 0.001) and ECE-2 (p < 0.01) levels were significantly reduced in DLB and both enzymes correlated inversely with the severity of Lewy body pathology as indicated by the level of α-syn phosphorylated at Ser129 (r = -0.54, p < 0.01 for ECE-1 and r = -0.49, p < 0.05 for ECE-2). Our novel findings suggest a role for ECEs in the metabolism of α-syn that could contribute to the development and progression of DLB.

Alteration of mitochondrial protein PDHA1 in Lewy body disease and PARK14.

The histopathological hallmark of Parkinson's disease (PD) and dementia with Lewy bodies (DLB) is the occurrence of insoluble fibrillary aggregates known as Lewy bodies. Mitochondria play a vital role in energy production, and the pathogenesis of PD is associated with altered cellular metabolism due to mitochondrial dysfunction. The pyruvate dehydrogenase (PDH) complex provides a primary step in aerobic glucose metabolism by catalyzing the oxidative decarboxylation of pyruvate to acetyl CoA. Pyruvate dehydrogenase alpha 1 (PDHA1) forms the core structure of the PDH complex. Dysfunction of the PDH complex leads to energy production failure, resulting in various neurological disorders. However, no study has investigated the involvement of PDHA1 in the pathogenesis of PD. In the present study, we performed immunohistochemistry and immunoblotting to clarify the involvement of PDHA1 in idiopathic PD, DLB, PARK14-linked parkinsonism (PARK14; a familial form of PD), and multiple system atrophy, in comparison with normal controls. Here we report PDHA1 as a new component of brainstem-type Lewy bodies in idiopathic PD, DLB and PARK14, the level of PDHA1 protein being significantly decreased in the putamen and substantia nigra of patients with idiopathic PD. Our findings suggest that alteration of glucose metabolism through dysfunction of the PDH complex might occur in the pathogenesis of Lewy body disease and PARK14.

Altered Expression of Human Mitochondrial Branched Chain Aminotransferase in Dementia with Lewy Bodies and Vascular Dementia.

Cytosolic and mitochondrial human branched chain aminotransferase (hBCATc and hBCATm, respectively) play an integral role in brain glutamate metabolism. Regional increased levels of hBCATc in the CA1 and CA4 region of Alzheimer's disease (AD) brain together with increased levels of hBCATm in frontal and temporal cortex of AD brains, suggest a role for these proteins in glutamate excitotoxicity. Glutamate toxicity is a key pathogenic feature of several neurological disorders including epilepsy associated dementia, AD, vascular dementia (VaD) and dementia with Lewy bodies (DLB). To further understand if these increases are specific to AD, the expression profiles of hBCATc and hBCATm were examined in other forms of dementia including DLB and VaD. Similar to AD, levels of hBCATm were significantly increased in the frontal and temporal cortex of VaD cases and in frontal cortex of DLB cases compared to controls, however there were no observed differences in hBCATc between groups in these areas. Moreover, multiple forms of hBCATm were observed that were particular to the disease state relative to matched controls. Real-time PCR revealed similar expression of hBCATm mRNA in frontal and temporal cortex for all cohort comparisons, whereas hBCATc mRNA expression was significantly increased in VaD cases compared to controls. Collectively our results suggest that hBCATm protein expression is significantly increased in the brains of DLB and VaD cases, similar to those reported in AD brain. These findings indicate a more global response to altered glutamate metabolism and suggest common metabolic responses that might reflect shared neurodegenerative mechanisms across several forms of dementia.

Hippocampal Lewy pathology and cholinergic dysfunction are associated with dementia in Parkinson's disease.

The neuropathological substrate of dementia in patients with Parkinson's disease is still under debate, particularly in patients with insufficient alternate neuropathology for other degenerative dementias. In patients with pure Lewy body Parkinson's disease, previous post-mortem studies have shown that dopaminergic and cholinergic regulatory projection systems degenerate, but the exact pathways that may explain the development of dementia in patients with Parkinson's disease remain unclear. Studies in rodents suggest that both the mesocorticolimbic dopaminergic and septohippocampal cholinergic pathways may functionally interact to regulate certain aspects of cognition, however, whether such an interaction occurs in humans is still poorly understood. In this study, we performed stereological analyses of the A9 and A10 dopaminergic neurons and Ch1, Ch2 and Ch4 cholinergic neurons located in the basal forebrain, along with an assessment of α-synuclein pathology in these regions and in the hippocampus of six demented and five non-demented patients with Parkinson's disease and five age-matched control individuals with no signs of neurological disease. Moreover, we measured choline acetyltransferase activity in the hippocampus and frontal cortex of eight demented and eight non-demented patients with Parkinson's disease, as well as in the same areas of eight age-matched controls. All patients with Parkinson's disease exhibited a similar 80-85% loss of pigmented A9 dopaminergic neurons, whereas patients with Parkinson's disease dementia presented an additional loss in the lateral part of A10 dopaminergic neurons as well as Ch4 nucleus basalis neurons. In contrast, medial A10 dopaminergic neurons and Ch1 and Ch2 cholinergic septal neurons were largely spared. Despite variable Ch4 cell loss, cortical but not hippocampal cholinergic activity was consistently reduced in all patients with Parkinson's disease, suggesting significant dysfunction in cortical cholinergic pathways before frank neuronal degeneration. Patients with Parkinson's disease dementia were differentiated by a significant reduction in hippocampal cholinergic activity, by a significant loss of non-pigmented lateral A10 dopaminergic neurons and Ch4 cholinergic neurons (30 and 55% cell loss, respectively, compared with neuronal preservation in control subjects), and by an increase in the severity of α-synuclein pathology in the basal forebrain and hippocampus. Overall, these results point to increasing α-synuclein deposition and hippocampal dysfunction in a setting of more widespread degeneration of cortical dopaminergic and cholinergic pathways as contributing to the dementia occurring in patients with pure Parkinson's disease. Furthermore, our findings support the concept that α-synuclein deposition is associated with significant neuronal dysfunction in the absence of frank neuronal loss in Parkinson's disease.

Gaucher disease: haematological presentations and complications.

Gaucher disease (GD) is an autosomal recessive lysosomal storage disease, caused by deficiency of the enzyme glucocerebrosidase, required for the degradation of glycosphingolipids. Clinical manifestations include hepatosplenomegaly, thrombocytopenia, bone disease and a bleeding diathesis, frequently resulting in presentation to haematologists. Historically managed by splenectomy, transfusions and orthopaedic surgery, the development of specific therapy in the form of intravenous enzyme replacement therapy in the 1990s has resulted in dramatic improvements in haematological and visceral disease. Recognition of complications, including multiple myeloma and Parkinson disease, has challenged the traditional macrophage-centric view of the pathophysiology of this disorder. The pathways by which enzyme deficiency results in the clinical manifestations of this disorder are poorly understood; altered inflammatory cytokine profiles, bioactive sphingolipid derivatives and alterations in the bone marrow microenvironment have been implicated. Further elucidating these pathways will serve to advance our understanding not only of GD, but of associated disorders.

Brain expression level and activity of HDAC6 protein in neurodegenerative dementia.

Histone deacetylase 6 (HDAC6) is a multifunctional cytoplasmic protein that plays an especially critical role in the formation of aggresomes, where aggregates of excess protein are deposited. Previous immunohistochemical studies have shown that HDAC6 accumulates in Lewy bodies in Parkinson's disease and dementia with Lewy bodies (DLB) as well as in glial cytoplasmic inclusions in multiple system atrophy (MSA). However, it is uncertain whether the level and activity of HDAC6 are altered in the brains of patients with neurodegenerative dementia. In the present study, we demonstrated that the level of HDAC6 was not altered in the temporal cortex of patients with Alzheimer's disease and DLB in comparison with controls. In contrast, the level of HDAC6 was significantly increased in the temporal cortex of patients with frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP) and in the cerebellar white matter of patients with MSA. However, the level of acetylated α-tubulin, one of the substrates of HDAC6, was not altered in FTLD-TDP and MSA relative to controls. These findings suggest that the induced level of HDAC6 in the brain is insufficient for manifestation of its activity in FTLD-TDP and MSA.

Glucocerebrosidase, a new player changing the old rules in Lewy body diseases.

Mutations in the gene encoding glucocerebrosidase (GBA1) cause Gaucher disease (GD), a lysosomal storage disease with recessive inheritance. Glucocerebrosidase (GCase) is a lysosomal lipid hydrolase that digests glycolipid substrates, such as glucosylceramide and glucosylsphingosine. GBA1 mutations have been implicated in Lewy body diseases (LBDs), such as Parkinson's disease and dementia with Lewy bodies. Parkinsonism occurs more frequently in certain types of GD, and GBA1 mutation carriers are more likely to have LBDs than non-carriers. Furthermore, GCase is often found in Lewy bodies, which are composed of α-synuclein fibrils as well as a variety of proteins and vesicles. In this review, we discuss potential mechanisms of action of GBA1 mutations in LBDs with particular emphasis on α-synuclein aggregation by reviewing the current literature on the role of GCase in lysosomal functions and glycolipid metabolism.

Imaging and acetylcholinesterase inhibitor response in dementia with Lewy bodies.

Acetylcholinesterase inhibitors are commonly used to treat patients with dementia with Lewy bodies. Hippocampal atrophy on magnetic resonance imaging and amyloid-ß load on positron emission tomography are associated with the Alzheimer's disease-related pathology in patients with dementia with Lewy bodies. To date, few studies have investigated imaging markers that predict treatment response in patients with dementia with Lewy bodies. Our objective was to determine whether imaging markers of Alzheimer's disease-related pathology such as hippocampal volume, brain amyloid-ß load on (11)C Pittsburgh compound B positron emission tomography predict treatment response to acetylcholinesterase inhibitors in patients with dementia with Lewy bodies. We performed a retrospective analysis on consecutive treatment-naive patients with dementia with Lewy bodies (n = 54) from the Mayo Clinic Alzheimer's Disease Research Centre who subsequently received acetylcholinesterase inhibitors and underwent magnetic resonance imaging with hippocampal volumetry. Baseline and follow-up assessments were obtained with the Mattis Dementia Rating Scale. Subjects were divided into three groups (reliable improvement, stable or reliable decline) using Dementia Rating Scale reliable change indices determined previously. Associations between hippocampal volumes and treatment response were tested with analysis of covariance adjusting for baseline Dementia Rating Scale, age, gender, magnetic resonance field strength and Dementia Rating Scale interval. Seven subjects underwent (11)C Pittsburgh compound B imaging within 12 weeks of magnetic resonance imaging. Global cortical (11)C Pittsburgh compound B retention (scaled to cerebellar retention) was calculated in these patients. Using a conservative psychometric method of assessing treatment response, there were 12 patients with reliable decline, 29 stable cases and 13 patients with reliable improvement. The improvers had significantly larger hippocampi than those that declined (P = 0.02) and the stable (P = 0.04) group. An exploratory analysis demonstrated larger grey matter volumes in the temporal and parietal lobes in improvers compared with those who declined (P < 0.05). The two patients who had a positive (11)C Pittsburgh compound B positron emission tomography scan declined and those who had a negative (11)C Pittsburgh compound B positron emission tomography scan improved or were stable after treatment. Patients with dementia with Lewy bodies who do not have the imaging features of coexistent Alzheimer's disease-related pathology are more likely to cognitively improve with acetylcholinesterase inhibitor treatment.

Isoform-specific upregulation of FynT kinase expression is associated with tauopathy and glial activation in Alzheimer's disease and Lewy body dementias.

Cumulative data suggest the involvement of Fyn tyrosine kinase in Alzheimer's disease (AD). Previously, our group has shown increased immunoreactivities of the FynT isoform in AD neocortex (with no change in the alternatively spliced FynB isoform) which associated with neurofibrillary degeneration and reactive astrogliosis. Since both the aforementioned neuropathological features are also variably found in Lewy Body dementias (LBD), we investigated potential perturbations of Fyn expression in the post-mortem neocortex of patients with AD, as well as those diagnosed as having one of the two main subgroups of LBD: Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB). We found selective upregulation of FynT expression in AD, PDD, and DLB which also correlated with cognitive impairment. Furthermore, increased FynT expression correlated with hallmark neuropathological lesions, soluble ß-amyloid, and phosphorylated tau, as well as markers of microglia and astrocyte activation. In line with the human post-mortem studies, cortical FynT expression in aged mice transgenic for human P301S tau was upregulated and further correlated with accumulation of aggregated phosphorylated tau as well as with microglial and astrocytic markers. Our findings provide further evidence for the involvement of FynT in neurodegenerative dementias, likely via effects on tauopathy and neuroinflammation.

The role of glucocerebrosidase mutations in Parkinson disease and Lewy body disorders.

Mutations in the gene encoding glucocerebrosidase (GBA), the enzyme deficient in the lysosomal storage disorder Gaucher disease, are associated with the development of Parkinson disease and other Lewy body disorders. In fact, GBA variants are currently the most common genetic risk factor associated with parkinsonism, and identified subjects with Parkinson disease are more than five times more likely to carry mutations in GBA. The mechanisms underlying this association are not known, but proposed theories include enhanced protein aggregation, alterations in lipid levels, and autophagy-lysosomal dysfunction promoting the retention of undegraded proteins. We review the genetic studies linking GBA to parkinsonism, as well as several of the mechanisms postulated to explain the association of GBA mutations and the synucleinopathies, which demonstrate how studies of a rare mendelian disease may provide insights into our understanding of a common complex disorder.

Caspase-cleaved transactivation response DNA-binding protein 43 in Parkinson's disease and dementia with Lewy bodies.

BACKGROUND: Transactivation response DNA-binding protein 43 (TDP-43) proteinopathies are classified based upon the extent of modified TDP-43 and include a growing number of neurodegenerative diseases such as amyotrophic lateral sclerosis, frontotemporal lobar degeneration with ubiquitin-immunoreactive, tau-negative inclusions and frontotemporal lobar degeneration with motor neuron disease. OBJECTIVE: The purpose of the study was to examine whether proteolytic modifications of TDP-43 are a relevant finding in Parkinson's disease (PD) and dementia with Lewy bodies (DLB). METHODS: A novel site-directed caspase cleavage antibody, termed TDP caspase cleavage product antibody (TDPccp), was utilized based upon a known caspase 3 cleavage consensus site within TDP-43 at position 219. RESULTS: Application of this antibody to postmortem brain sections from PD and DLB patients revealed the presence of caspase-cleaved TDP-43 in Lewy bodies and Hirano bodies in all cases examined. Colocalization of TDPccp with an antibody to alpha-synuclein (alpha-Syn), which served as a general marker for Lewy bodies, was evident within the substantia nigra in both alpha-synucleinopathies. Interestingly, the TDPccp antibody detected a greater number of Lewy bodies in PD and DLB compared to the alpha-Syn antibody. In addition, a semiquantitative analysis in both diseases confirmed this finding by indicating that the percentage of caspase-cleaved TDP-43 single-labeled Lewy bodies was approximately twice that of alpha-Syn labeling (in DLB 13.4 vs. 5.5%, while in PD 34.6 vs. 17.6%). CONCLUSION: Collectively, these data have identified caspase-cleaved TDP-43 as a primary component of Lewy and Hirano bodies in PD and DLB, and suggest that the TDPccp antibody is an effective marker for the detection of Lewy bodies in these neurodegenerative diseases.

Cerebrospinal fluid beta-glucocerebrosidase activity is reduced in Dementia with Lewy Bodies.

The autophagy-lysosomal degradation pathway plays a role in the onset and progression of neurodegenerative diseases. Clinical and genetic studies indicate that mutations of beta-glucocerebrosidase represent genetic risk factors for synucleinopathies, including Parkinson's Disease (PD) and Dementia with Lewy Bodies (DLB). We recently found a decreased activity of lysosomal hydrolases, namely beta-glucocerebrosidase, in cerebrospinal fluid of PD patients. We have thus measured the activity of these enzymes - alpha-mannosidase (EC 3.2.1.24), beta-mannosidase (EC 3.2.1.25), beta-glucocerebrosidase (EC 3.2.1.45), beta-galactosidase (EC 3.2.1.23) and beta-hexosaminidase (EC 3.2.1.52) - in cerebrospinal fluid of patients suffering from DLB, Alzheimer's Disease (AD), Fronto-Temporal Dementia (FTD) and controls. Alpha-mannosidase activity showed a marked decrease across all the pathological groups as compared to controls. Conversely, beta-glucocerebrosidase activity was selectively reduced in DLB, further suggesting that this enzyme might specifically be impaired in synucleinopathies.

No differences of butyrylcholinesterase protein activity and allele frequency in Lewy body diseases.

Butyrylcholinesterase (BChE) genotypes and protein (BuChE) activity, especially in combination with Apolipoprotein E4 (ApoE4), have been investigated as risk factors for developing Alzheimer disease (AD) and may be associated with the rate of progression of cognitive decline. Despite similar pathologic (e.g. amyloid deposition) and neurochemical (e.g. cholinergic deficits) aspects between AD and Lewy body diseases (LBD), scarce data is obtainable about BChE genotypes and BuChE activity in LBD. We measured BuChE activity levels in serum and cerebrospinal fluid (CSF) of 114 LBD subjects (59 of them were demented) and 31 elderly controls. We found higher CSF BuChE activity in males compared to females, and a negative correlation of serum BuChE activity with age and cognitive function. Demented LBD patients, non-demented LBD patients and controls did not differ significantly with regard to serum and CSF BuChE activity. Furthermore, BChE K variant and ApoE4 allele frequencies were determined. The BChE K variant was significantly associated with lower serum activity; the same trend was observable in CSF. The subgroups did not differ significantly with regard to BChE K/ApoE4 occurrence. These data confirm and extend previous results on the relationship between BChE gene and BuChE activity, and argue rather against a major impact of BuChE on LBD-associated pathologies.

Age-related neurochemical and behavioural changes in D409V/WT GBA1 mouse: Relevance to lewy body dementia.

Heterozygous mutations in GBA1, the gene which encodes the lysosomal enzyme glucocerebrosidase (GCase), are a strong genetic risk factor for the development of Lewy body dementia (LBD). Until this point however, recapitulation of the symptoms and pathology of LBD has been limited to a homozygous GBA1 mouse model which genetically and enzymatically reflects the lysosomal storage disorder Gaucher's disease. This study reports for the first time cognitive impairment by two independent behavioural tests in heterozygous GBA1 mutant mice (D409V/WT) which demonstrate significant cognitive impairment by the age of 12 months. Furthermore, reductions in GBA1 GCase enzyme activity within the brain reflects levels seen in sporadic and GBA1 mutant LBD patients. While there is no overt deposition of Lewy bodies within the hippocampus, alterations to cholinergic machinery and glial proliferation are evident, both pathological features of LBD. Interestingly, we also describe the novel finding of significantly reduced GBA2 GCase enzyme activity specifically within the hippocampus. This suggests that reduced GBA1 GCase enzyme activity dis-equilibrates the finely balanced glycosphingolipid metabolism pathway and that reductions in GBA2 GCase enzyme could contribute to the pathological and behavioural effects seen. Overall, this study presents evidence to suggest that pathological hallmarks associated with LBD specifically affecting brain regions intrinsically linked with cognition are present in the D409V/WT mice. In the absence of Lewy body deposition, the D409V/WT mice could be considered an early pre-clinical model of LBD with potential for drug discovery. Since few robust pre-clinical models of LBD currently exist, with further characterization, the mouse model described here may contribute significantly to developments in the LBD field.

Proton magnetic resonance spectroscopy detects a relative decrease of N-acetylaspartate in the hippocampus of patients with dementia with Lewy bodies.

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.

Cerebrospinal fluid neuron-specific enolase: a further marker of Alzheimer's disease?

To investigate whether neuron-specific enolase (NSE) plays a role in dementia, we measured cerebrospinal fluid (CSF) concentrations of NSE, Abeta42 and total protein tau (h-tau) in different dementia patients. We studied 159 patients: 76 with Alzheimer's disease (AD), 35 with mild cognitive impairment (MCI), 28 with frontotemporal dementia (FTD), and 20 with Lewy body disease (LBD). Thirty healthy age-matched subjects were studied as controls. NSE was measured by immunoradiometric assay, Abeta42 and h-tau were dosed by ELISA assay. Mean CSF NSE was significantly higher in AD (15.1+/-9.9 ng/ml) than in controls (8.3+/-3.5 ng/ml, p<0.01), FTD (9.1+/-6.1 ng/ml, p<0.05) and MCI (9.7+/-7.8 ng/ml, p<0.05). Ab42 was significantly lower in AD (413.8+/-163.7 pg/ml) than in MCI (708.4+/-422.1 pg/ml, p<0.001) and controls (914.4+/-277.1 pg/ml, p<0.05); it was also significantly reduced in FTD (497.1+/-221.9 pg/ml) versus MCI (p<0.05) and controls (p<0.001); and in LBD patients (477.1+/-225.7 pg/ml) compared with MCI (p<0.05) and controls (p<0.001). H-tau concentration was significantly higher in AD (607.9+/-372.3 pg/ml, p<0.001) than in MCI (383.8+/-277.9 pg/ml, p<0.05), controls (176.6+/-43.9 pg/ml, p<0.001) and LBD (472.3+/-357.7 pg/ml, p<0.05); it was also increased in FTD (541.76+/-362.8 pg/ml) versus contro s (176.6+/-43.9 pg/ml, p<0.001). Furthermore, NSE was inversely correlated with Ab42 (r=-0.333, p=0<0001) and directly correlated with h-tau (r=0.370, p=0<0001). In conclusion, CSF NSE emerged as a specific indicator of AD and showed the same behaviour as the other accepted markers of AD, being correlated with both biomarkers.

Upregulation of PSMB8 and cathepsins in the human brains of dementia with Lewy bodies.

Proteasome and lysosome are responsible for the homeostasis of proteins, lipids and carbohydrates in cells. Numerous reports indicate the proteolytic pathways have altered functions during neurodegeneration and aging. Dementia with Lewy bodies (DLB) is one of the leading forms of dementia, and the proteolytic alteration in DLB has not yet been fully investigated. This study shows that the components of proteasome and lysosome had selectively altered gene expression and enzymatic functions. Specifically, PSMB8, an inducible proteasomal ß subunit, had elevated mRNA level and protein level in DLB brain compared with age-matched controls. The proteasomal caspase-like peptidase showed significant decreased activity in DLB brains and the trypsin-like/chemotrypsin-like activities did not reach statistical significance. Lysosomal cathepsin B and D had elevated mRNA levels while only cathepsin B showed elevated enzymatic activity in DLB brains. This data indicate that the alteration of proteolytic pathways is highly selective and comprehensive. Further study to elucidate the correlation between neurodegenerative development and the alteration of proteolytic pathways would be important for therapeutic development.

Lewy body disease: thalamic cholinergic activity related to dementia and parkinsonism.

Within the spectrum of Lewy body disease cognitive impairment occurs in PD with dementia (PDD) and dementia with Lewy bodies (DLB). Although neocortical cholinergic deficits are associated with cognitive impairments in PDD and DLB, no neurochemical study has been published describing the thalamic cholinergic activity whereas the thalamus plays a major role in modulating cortical activity. Choline acetyltransferase (ChAT) activity was analyzed in reticular (Re), mediodorsal (MD) and centromedian (CM) thalamic nuclei in series of nine controls, five DLB with parkinsonism (DLB + P), five DLB without parkinsonism (DLB - P), six PD without dementia and 14 PDD cases. Significant reductions in ChAT were apparent in PDD as follows: in Re and MD nuclei compared with controls; in MD and CM nuclei compared with DLB + P; and in MD compared with PD. Increased ChAT activity was found in CM nuclei in DLB + P compared with DLB - P. These findings show that significant thalamic presynaptic cholinergic deficits occur only in cases of combined cortical and subcortical neurodegeneration in which dementia developed after prolonged parkinsonism.

Early and widespread cholinergic losses differentiate dementia with Lewy bodies from Alzheimer disease.

BACKGROUND: Reductions in cholinergic function occur in Alzheimer disease (AD) and dementia with Lewy bodies and correlate with cognitive decline. However, whether such alterations appear in early-stage disease is unclear. OBJECTIVE: To examine the timing of cholinergic deficits in AD and dementia with Lewy bodies. METHODS: Autopsy series of 89 patients with AD and 50 patients with the Lewy body variant of AD (LBV). Stage of disease was stratified according to results of the last Mini-Mental State Examination (MMSE) before death as mild, moderate, severe, or very severe. We analyzed choline acetyltransferase (ChAT) activity in the midfrontal, superior temporal, and inferior parietal cortices. RESULTS: Although compared with a normal control group ChAT activity was decreased in the AD and LBV cohorts, ChAT activity reduction for the LBV cohort was much greater. Moreover, although the decline in ChAT activity in the AD cohort compared with the normal control group was significant only for patients in later stages of the illness, the decline in the LBV cohort was significant for those who died with mild-stage disease. When less impaired patients in each cohort (MMSE, > or = 10) underwent separate analysis, the relationship of ChAT activity with the MMSE score was strong and significant for the LBV cohort alone. CONCLUSIONS: Although cholinergic deficits are seen in both AD and LBV, loss of ChAT activity is less severe and occurs later in the clinical course of AD. Conversely, in LBV, loss of ChAT activity is already prominent in the earliest stages of the illness, suggesting that cholinergic replacement therapy may be more effective in LBV than in AD, especially in mild-stage disease.