Takayoshi Tokutake

Differential levels of α-synuclein, β-amyloid42 and tau in CSF between patients with dementia with Lewy bodies and Alzheimer's disease

Background The clinical diagnosis of dementia with Lewy bodies (DLB) is made on the basis of consensus criteria; however, the sensitivity of the criteria is relatively low. There are no generally accepted biomarkers to distinguish DLB from other dementias. Here the utility of quantification of α-synuclein, β-amyloid42 (Aβ42) and tau in the CSF of patients with DLB, Alzheimers disease (AD) and other dementias was examined. Methods 86 patients were divided into three age and sex matched groups: DLB (n=34), AD (n=31) and other dementias (n=21). Two patients with α-synuclein gene (SNCA) duplication were also examined. Aβ and tau were quantified using an ELISA kit. A modified sandwich ELISA was developed which enables the sensitive quantification of CSF α-synuclein. Results Total and phosphorylated tau levels as well as Aβ40/42 and tau/Aβ42 ratios were significantly higher in AD patients than in patients with DLB (p<0.01) and other dementias (p<0.01). CSF α-synuclein levels in DLB patients were significantly lower than those in patients with AD (p<0.05) and other dementias (p<0.01). CSF α-synuclein level correlated with the Aβ42 level in DLB patients (p=0.01, r=0.43). Two patients with SNCA duplication exhibited relatively low levels of CSF α-synuclein. Conclusions The study suggests that reduced levels of CSF α-synuclein in DLB may reflect the accumulation of α-synuclein with Lewy pathology in the brain and that quantification of CSF α-synuclein helps in the differentiation of DLB from AD and other dementias in combination with Aβ42 and tau analysis.

Hyperphosphorylation of Tau Induced by Naturally Secreted Amyloid-β at Nanomolar Concentrations Is Modulated by Insulin-dependent Akt-GSK3β Signaling Pathway

Background: Little is known about the underlying mechanisms by which extracellular amyloid-β (Aβ) induces Tau phosphorylation in Alzheimer disease (AD). Results: Naturally secreted Aβ induced hyperphosphorylation of Tau and impaired insulin signal transduction. Conclusion: A disturbed insulin signaling cascade may be implicated in the pathway of Aβ-induced Tau hyperphosphorylation. Significance: These findings may explain the molecular link between Alzheimer disease and insulin signaling. Alzheimer disease (AD) is neuropathologically characterized by the formation of senile plaques from amyloid-β (Aβ) and neurofibrillary tangles composed of phosphorylated Tau. Although there is growing evidence for the pathogenic role of soluble Aβ species in AD, the major question of how Aβ induces hyperphosphorylation of Tau remains unanswered. To address this question, we here developed a novel cell coculture system to assess the effect of extracellular Aβ at physiologically relevant levels naturally secreted from donor cells on the phosphorylation of Tau in recipient cells. Using this assay, we demonstrated that physiologically relevant levels of secreted Aβ are sufficient to cause hyperphosphorylation of Tau in recipient N2a cells expressing human Tau and in primary culture neurons. This hyperphosphorylation of Tau is inhibited by blocking Aβ production in donor cells. The expression of familial AD-linked PSEN1 mutants and APP ΔE693 mutant that induce the production of oligomeric Aβ in donor cells results in a similar hyperphosphorylation of Tau in recipient cells. The mechanism underlying the Aβ-induced Tau hyperphosphorylation is mediated by the impaired insulin signal transduction because we demonstrated that the phosphorylation of Akt and GSK3β upon insulin stimulation is less activated under this condition. Treating cells with the insulin-sensitizing drug rosiglitazone, a peroxisome proliferator-activated receptor γ agonist, attenuates the Aβ-dependent hyperphosphorylation of Tau. These findings suggest that the disturbed insulin signaling cascade may be implicated in the pathways through which soluble Aβ induces Tau phosphorylation and further support the notion that correcting insulin signal dysregulation in AD may offer a potential therapeutic approach.

Increased Levels of Soluble LR11 in Cerebrospinal Fluid of Patients with Alzheimer Disease

Background: Recent genetic and pathological studies have suggested that a lipoprotein receptor, LR11, is intricately implicated in the pathogenesis of Alzheimer disease (AD). We have recently established a novel sandwich ELISA, which enabled the sensitive quantification of a soluble LR11 (sLR11). By this ELISA, we attempted to determine the difference in the levels of CSF sLR11 in AD patients. Methods: We examined CSF from 29 AD patients, 20 frontotemporal lobar degeneration patients and 27 age-matched control subjects. The CSF sLR11 level as well as the levels of tau and β-amyloid42 (Aβ42) were determined by sandwich ELISA. Results: The CSF tau level and tau/Aβ42 ratio were significantly increased (p < 0.01) in the AD patients. The CSF sLR11 level in the AD patients was significantly higher (p < 0.01) than that of the frontotemporal lobar degeneration patients and the controls. The APOE-Ε4-positive AD patients have higher sLR11 levels than the APOE-Ε4-negative patients (p < 0.01). Conclusions: These results suggest that the quantification of CSF sLR11 may serve as a biomarker of AD, although the diagnostic value for individual patients is limited. An elevated CSF sLR11 level in AD patients may be relevant to AD pathogenesis.

Clinical and neuroimaging features of patient with early-onset Parkinson's disease with dementia carrying SNCA p.G51D mutation

Mutations in the a-synuclein gene (SNCA) have been shown to cause familial parkinsonism with or without cognitive decline. Three known missense mutations including A53T, A30P, and E46K as well as gene dosage alteration of SNCA by multiplication were shown to cause familial or apparently sporadic parkinsonism and dementia [1]. Recently, two additional missense SNCA mutations, p.H50Q [2,3] and p.G51D [4,5], have been identified in patients with familial parkinsonism. We here report the case of a Japanese patient with SNCA p.G51D mutation who developed early-onset Parkinson’s disease followed by prominent cognitive decline, psychiatric symptoms, and autonomic disturbance. The patient was a 42-year-old female born to nonconsanguineous parents who were neurologically intact at ages of 66 and 64. She has a younger brother, who was healthy at the age of 39 years. Her paternal grandfather developed Parkinson’s disease in his seventies and died at the age of 84. No other neurological disease was observed in the family. She developed bradykinesia, gait disturbance, and postural instability at the age of 28. She was diagnosed as having juvenile parkinsonism and treated with L-dopa (300 mg/day), which provided substantial symptomatic benefits but induced dyskinesia. At the age of 30, hallucination was first noted when on medication with trihexyphenidyl. Subsequently, well-formed visual hallucination and prominent psychiatric symptoms including delusion, impulsion, and excitability repetitively occurred independent of anti-parkinsonian medication. Neurological examination revealed cognitive decline, rigidity, postural imbalance, hyperreflexia without extensor plantar reflexes, spasticity, and bradykinesia. No rest tremor was noted. At the age of 34, she gradually became aspontaneous and incapable of verbal communication, and her Mini-Mental Scale Examination score was 0/30. Autonomic dysfunctions including orthostatic hypotension with syncope and urinary incontinence were noted. She exhibited myoclonus and had tonic seizures. Fourteen years after the onset, she became wheelchair-bound owing to the worsening of her motor symptoms staged at Hoehn and Yahr V. These clinical features led us to diagnose the patient clinically as having earlyonset Parkinson’s disease with dementia.

Diagnostic Value of Brain Calcifications in Adult-Onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia

SUMMARY: Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia is a rare neurodegenerative disease resulting from mutations in the colony stimulating factor 1 receptor gene. Accurate diagnosis can be difficult because the associated clinical and MR imaging findings are nonspecific. We present 9 cases with intracranial calcifications distributed in 2 brain regions: the frontal white matter adjacent to the anterior horns of the lateral ventricles and the parietal subcortical white matter. Thin-section (1-mm) CT scans are particularly helpful in detection due to the small size of the calcifications. These calcifications had a symmetric “stepping stone appearance” in the frontal pericallosal regions, which was clearly visible on reconstructed sagittal CT images. Intrafamilial variability was seen in 2 of the families, and calcifications were seen at birth in a single individual. These characteristic calcification patterns may assist in making a correct diagnosis and may contribute to understanding of the pathogenesis of leukoencephalopathy.

Maintaining glottic opening in multiple system atrophy: efficacy of serotonergic therapy.

Involuntary muscle contractions began in the right deltoid muscle 2 weeks after onset of pain. Contractions were rhythmic, with sinusoidal and undulating/peristaltic qualities. Both the pain and the deltoid contractions were continuous. The movements continued during sleep, and the patient could not voluntarily stop them. Therapeutic interventions including medications, physical therapy, and surgery did not mitigate the pain or affect the movements. Oral analgesics including oxycodone and antiepileptics including phenytoin and gabapentin all proved ineffective. The patient was treated by chiropractors and physical therapists with no benefit. In 2001, a shoulder spur was removed, and later that year an anterior cervical discectomy with fusion at 3 levels (C4–C5, C5–C6, and C6–C7) was performed. Neither surgery produced benefit. On exam, the patient had no focal motor or sensory deficits. Tendon reflexes were normal. Involuntary movements in the right deltoid were constant, although the amplitude, frequency, and extent of contractions varied. Contraction ‘‘waves’’ were rhythmic and began in the posterior deltoid, swept anteriorly, and gave an ‘‘undulating’’ or peristalsislike appearance. Contraction progression involved more muscle fascicles in the posterior middle-deltoid and was more visible with large amplitude contractions (see Video Supplement). His multiple spine magnetic resonance images revealed progressively worsening cervical spondylosis. Multichannel needle electromyographic (EMG) recording was performed with concentric needle electrodes. Deltoid EMG did not show myokymia or myoclonus. EMG activity underlying the contractions were normal-appearing interference patterns with bursts lasting 400–800 ms. During voluntary shoulder abduction, the bursting temporarily disappeared and was replaced by normal-looking tonic EMG activity. There were no other EMG abnormalities in the upper extremities. The pathophysiology of PLMT is poorly understood and likely heterogeneous. In some cases there is evidence of a lesion in the spinal cord, the cauda equina, the lumbar roots, or the peripheral nerves; the syndrome may also occur after minor limb trauma or without any antecedents. In at least 1 publication on PLMT, it was observed that movements could be suppressed at the patient’s volition. Peripheral nervous injury may produce a spectrum of movement disorders including PLMT, yet such etiology is not always confirmed by routine EMG, similar to our case. In the absence of confirmed peripheral nerve injury, the pathophysiology of these symptoms remains uncertain but likely arises from aberrant spinal cord plasticity. Painful shoulder—moving deltoid syndrome represents a spinal segmental movement disorder possibly analogous to PLMT.

Evidence for a Common Founder and Clinical Characteristics of Japanese Families with the MAPT R406W Mutation.

Background/Aim: Mutations in MAPT cause frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17). Patients with the MAPT R406W mutation were reported to show phenotypic heterogeneity in different ethnic backgrounds. We here report the clinical and genetic characteristics of Japanese families with the R406W mutation. Methods: We examined the clinical and neuroimaging features of 6 patients from three families with the R406W mutation. We determined the genotypes of intragenic MAPT single-nucleotide polymorphisms (SNPs) and the flanking microsatellite markers to search for a common founder. Results: The initial symptom was memory loss with the average age at onset being 54 years. Anterograde amnesia with episodic memory impairment was the predominant phenotype. Behavioral and personality changes or parkinsonism is not a prominent feature. A brain MRI study revealed marked atrophy of the medial temporal lobe. Genetic analysis of SNPs and microsatellite markers revealed that the affected members of the three families share common genotypes. Conclusion: The findings of the affected members in this study, which corroborate previously reported findings of European families, suggest that the R406W mutation may represent a phenotype of predominant anterograde amnesia in FTLD-17. Our genetic data suggest that a founder effect may account for some families with the R406W mutation.

ApoE-isoform-dependent cellular uptake of amyloid-β is mediated by lipoprotein receptor LR11/SorLA

The formation of senile plaques composed of β-amyloid (Aβ) in the brain is likely the initial event in Alzheimers disease (AD). Possession of the APOE ε4 allele, the strong genetic factor for AD, facilitates the Aβ deposition from the presymptomatic stage of AD in a gene-dosage-dependent manner. However, the precise mechanism by which apoE isoforms differentially induce the AD pathology is largely unknown. LR11/SorLA is a type I membrane protein that functions as the neuronal lipoprotein endocytic receptor of apoE and the sorting receptor of the amyloid precursor protein (APP) to regulate amyloidogenesis. Recently, LR11/SorLA has been reported to be involved in the lysosomal targeting of extracellular amyloid-β (Aβ) through the binding of Aβ to the vacuolar protein sorting 10 (VPS10) protein domain of LR11/SorLA. Here, we attempted to examine the human-apoE-isoform-dependent effect on the cellular uptake of Aβ through the formation of a complex between an apoE isoform and LR11/SorLA. Cell culture experiments using Neuro2a cells revealed that the cellular uptake of secreted apoE3 and apoE4 was enhanced by the overexpression of LR11/SorLA. In contrast, the cellular uptake of apoE2 was not affected by the expression of LR11/SorLA. Co-immunoprecipitation assay revealed that apoE-isoform-dependent differences were observed in the formation of an apoE-LR11 complex (apoE4>apoE3>apoE2). ApoE-isoform-dependent differences in cellular uptake of FAM-labeled Aβ were further investigated by coculture assay in which donor cells secrete one of the apoE isoforms and recipient cells express FL-LR11. The cellular uptake of extracellular Aβ into the recipient cells was most prominently accentuated when cocultured with the donor cells secreting apoE4 in the medium, followed by apoE3 and apoE2. Taken together, our results provide evidence for the mechanism whereby human-apoE-isoform-dependent differences modulate the cellular uptake of Aβ mediated by LR11/SorLA.

Systematic review and meta-analysis of Japanese familial Alzheimer's disease and FTDP-17

Mutations in APP, PSEN1 and PSEN2 as the genetic causes of familial Alzheimer’s disease (FAD) have been found in various ethnic populations. A substantial number of FAD pedigrees with mutations have been reported in the Japanese population; however, it remains unclear whether the genetic and clinical features of FAD in the Japanese population differ from those in other populations. To address this issue, we conducted a systematic review and meta-analysis of Japanese FAD and frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17) by literature search. Using this analysis, we identified 39 different PSEN1 mutations in 140 patients, 5 APP mutations in 35 patients and 16 MAPT mutations in 84 patients. There was no PSEN2 mutation among Japanese patients. The age at onset in Japanese FAD patients with PSEN1 mutations was significantly younger than that in patients with APP mutations. Kaplan–Meier analysis revealed that patients with MAPT mutations showed a shorter survival than patients with PSEN1 or APP mutations. Patients with mutations in different genes exhibit characteristic clinical presentations, suggesting that mutations in causative genes may modify the clinical presentations. By collecting and cataloging genetic and clinical information on Japanese FAD and FTDP-17, we developed an original database designated as Japanese Familial Alzheimers Disease Database, which is accessible at http://alzdb.bri.niigata-u.ac.jp/.

A Patient with Fragile X-Associated Tremor/Ataxia Syndrome Presenting with Executive Cognitive Deficits and Cerebral White Matter Lesions

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder that primarily affects males who are carriers of a premutation of a CGG expansion in the FMR1 gene. In Asian populations, FXTAS has rarely been reported. Here, we report the case of a Japanese FXTAS patient who showed predominant executive cognitive deficits as the main feature of his disease. In contrast, the patient exhibited only very mild symptoms of intention tremor and ataxia, which did not interfere with daily activities. A gene analysis revealed that the patient carried a premutation of a CGG expansion (111 CGG repeats) in the FMR1 gene. The mRNA expression level of FMR1 in the patient was 1.5-fold higher than in controls. On brain MRI scans, fluid-attenuated inversion recovery images showed high-intensity lesions in the middle cerebellar peduncles and the cerebral white matter, with a frontal predominance. The present case extends previous notions regarding the cognitive impairment in FXTAS patients. Recognizing FXTAS patients with predominant cognitive impairment from various ethnic backgrounds would contribute to our understanding of the phenotypic variation of this disease.