IgG index of cerebrospinal fluid can reflect pathophysiology associated with Lewy bodies in Parkinson's disease.

BACKGROUND: Neuroinflammation is one of the pathophysiologies of Parkinson's disease (PD). Lewy bodies, the pathological hallmark of PD, emerge as a consequence of α-synuclein aggregation, and neuroinflammation is induced concurrently with this aggregation. Imaging and cerebrospinal fluid (CSF) biomarkers that reflect PD pathophysiology have been developed or are under investigation. The IgG index of CSF is a marker of inflammation, and may also reflect the pathophysiology of PD. AIM: We examined if the IgG index reflects the pathophysiology of PD in drug-naïve PD patients. METHOD: The subjects were 20 consecutive PD patients who underwent 123I-MIBG scintigraphy for assessment of the heart to mediastinum (H/M) ratio and wash out rate, 123I-Ioflupane SPECT for examination of the specific binding ratio in the striatum, and lumbar puncture before treatment. The CSF IgG index and levels of pathogenic proteins (total α-synuclein, oligomeric α-synuclein, total tau, phosphorylated tau and amyloid Aß1-42) were determined. The IgG index was compared with the other parameters using Spearman correlation analysis. RESULTS: The IgG index showed a significant correlation with the H/M ratio in early (r = -0.563, p = 0.010) and delayed (r = -0.466, p = 0.038) images in 123I-MIBG scintigraphy and with the CSF total tau level (r = -0.513, p = 0.021). CONCLUSION: Neuroinflammation is involved in PD pathophysiology in some patients, and a higher IgG index indicates the presence of neuroinflammation accompanied by emergence of Lewy bodies.

The clinical application of optimized AT(N) classification in Alzheimer's clinical syndrome (ACS) and non-ACS conditions.

We aimed to assess the utility of AT(N) classification in clinical practice. We measured the cerebrospinal fluid levels of amyloid-ß (Aß) 42, Aß40, phosphorylated tau, total tau, and neurofilament light chain (NfL) in samples from 230 patients with Alzheimer's clinical syndrome (ACS) and 328 patients with non-ACS. The concordance of two A-markers (i.e., Aß42 alone and the Aß42/Aß40 ratio) was not significantly different between the ACS (87.4%) and non-ACS (74.1%) groups. However, the frequency of discordant cases with AAß42-alone+/AAß-ratio- was significantly higher in the non-ACS (23.8%) than in the ACS group (7.4%). The concordance of two N-markers (i.e., total tau and NfL) was 40.4% in the ACS group and 24.4% in the non-ACS group. In the ACS samples, the frequency of biological Alzheimer's disease (i.e., A+T+) in Ntau+ cases was 95% while that in NNfL+ cases was 65%. Reflecting Aß deposition and neurodegeneration more accurately, we recommend the use of AT(N) classification defined by cerebrospinal fluid AAß-ratioTNNfL in clinical practice.

Different AT(N) profiles and clinical progression classified by two different N markers using total tau and neurofilament light chain in cerebrospinal fluid.

Background: The AT(N) classification was proposed for categorising individuals according to biomarkers. However, AT(N) profiles may vary depending on the markers chosen and the target population. Methods: We stratified 177 individuals who participated in the Japanese Alzheimer's Disease Neuroimaging Initiative by AT(N) classification according to cerebrospinal fluid (CSF) biomarkers. We compared the frequency of AT(N) profiles between the classification using total tau and neurofilament light chain (NfL) as N markers (AT(N)tau and AT(N)NfL). Baseline characteristics, and longitudinal biological and clinical changes were examined between AT(N) profiles. Results: We found that 9% of cognitively unimpaired subjects, 49% of subjects with mild cognitive impairment, and 61% of patients with Alzheimer's disease (AD) dementia had the biological AD profile (ie, A+T+) in the cohort. The frequency of AT(N) profiles substantially differed between the AT(N)tau and AT(N)NfL classifications. When we used t-tau as the N marker (AT(N)tau), those who had T- were more frequently assigned to (N)-, whereas those who had T+were more frequently assigned to (N)+ than when we used NfL as the N marker (AT(N)NfL). During a follow-up, the AD continuum group progressed clinically and biologically compared with the normal biomarker group in both the AT(N)tau and AT(N)NfL classifications. More frequent conversion to dementia was observed in the non-AD pathological change group in the AT(N)tau classification, but not in the AT(N)NfL classification. Conclusions: AT(N)tau and AT(N)NfL in CSF may capture different aspects of neurodegeneration and provide a different prognostic value. The AT(N) classification aids in understanding the AD continuum biology in various populations.

Effects of an essential amino acid mixture on behavioral and psychological symptoms of dementia and executive function in patients with Alzheimer's disease: A double-blind, randomized, placebo-controlled exploratory clinical trial.

BACKGROUND: The increasing number of dementia patients has become a global social problem. Amino acids are known to be used as precursors of neurotransmitters in the brain. Amino acid mixtures as a supplement may be used as a solution to Alzheimer's symptoms. This exploratory study evaluated the efficacy and safety of a mixture containing nine essential amino acids on behavioral and psychological symptoms of dementia (BPSD) and cognitive function in patients with Alzheimer's disease (AD). DESIGN: We conducted a double-blind, randomized, placebo-controlled trial to evaluate the intervention effects of nine essential amino acid mixture for 28 days. A total of 36 patients with AD were enrolled in Japan. BPSD and cognitive function were evaluated by the Neuropsychiatric Inventory-12 item (NPI-12; the primary endpoint), Mini-Mental State Examination (MMSE), Trail Making Test A (TMT-A), Trail Making Test B (TMT-B), Frontal Assessment Battery (FAB), and Clinical Dementia Rating Scale (CDR). RESULTS: Compared with placebo, the amino acid mixture did not improve NPI-12, MMSE, TMT-A and B or CDR scores. However, the analysis of covariance revealed improved FAB scores in the amino acid mixture group as a secondary endpoint. There were four subjects with adverse events in each group. CONCLUSIONS: Our results did not show a beneficial effect of the mixture containing nine essential amino acids on BPSD as a primary endpoint; however, it may improve executive function in patients with AD.

Clinical correlations of cerebrospinal fluid biomarkers including neuron-glia 2 and neurofilament light chain in patients with multiple system atrophy.

BACKGROUND: Multiple system atrophy (MSA) is a progressive neurodegenerative disorder. The usefulness of biomarkers in diagnosing MSA has been recently reported, but few studies have investigated the correlations among cerebrospinal fluid (CSF) biomarkers or the relationship between CSF biomarkers and the clinical parameters of patients with MSA. Thus, this was the aim of our study. METHODS: We performed cross-sectional study of CSF biomarkers in 50 patients with MSA and 20 control subjects. Ten of the patients with MSA were longitudinally followed for a period of 2 ± 1 years (mean ± standard deviation) as a substudy. We quantified CSF biomarkers including α-synuclein (α-syn), ß-amyloid42 (Aß42), total tau (t-tau) and phosphorylated tau (p-tau), neurofilament light chain (NfL), and neuron-glia2 (NG2), and assessed their relationship with clinical parameters (clinical subtypes, motor symptoms, nonmotor symptoms, and disease progression). RESULTS: The levels of CSF α-syn, Aß42, and p-tau were significantly lower, while those of NfL were higher in the patients with MSA than in the control subjects. Importantly, we found the significant elevation of soluble NG2 in the CSF of patients with MSA. CSF NfL showed the optimal diagnostic performance for MSA with levels at baseline significantly associated with longitudinal motor progression. With the exception of t-tau, there were no differences in the levels of CSF biomarkers between the MSA-parkinsonism and MSA-cerebellar subtypes. CONCLUSIONS: Our results suggest CSF levels of NG2 and NfL as possible diagnostic and prognostic biomarkers in MSA. Further study is necessary to validate these findings.

Correlated levels of cerebrospinal fluid pathogenic proteins in drug-naïve Parkinson's disease.

BACKGROUND AND AIM: Toxic oligomeric α-synuclein (αS; O-αS) has been suggested to play a central role in the pathogenesis of Lewy body diseases such as Parkinson's disease (PD). Cerebrospinal fluid (CSF) levels of αS, O-αS, total and phosphorylated tau, and amyloid ß 1-42 (Aß1-42) are thought to reflect the pathophysiology or clinical symptoms in PD. In this study, we examined correlations of the CSF levels of these proteins with the clinical symptoms, and with each other in drug-naïve patients with PD. METHODS: Twenty-seven drug-naïve patients with PD were included. Motor and cognitive functions were assessed using the Unified Parkinson's Disease Rating Scale (UPDRS), Montreal Cognitive Assessment (MoCA), and Neurobehavioral Cognitive Status Examination (COGNISTAT). CSF levels of total αS, O-αS, Aß1-42, total tau and tau phosphorylated at threonine 181 (P-tau181p) were measured. CSF levels of these proteins were compared with clinical assessments from the UPDRS, MoCA and COGNISTAT using Spearman correlation analysis. Spearman correlation coefficients among CSF protein levels were also evaluated. RESULTS: CSF levels of αS were negatively correlated with UPDRS part III (motor score) (p < 0.05) and bradykinesia (p < 0.01), and positively correlated with COGNISTAT subtest of judgement (p < 0.01) and CSF levels of Aß1-42 (p < 0.001), total tau (p < 0.001) and P-tau181p (p < 0.01). Lower CSF levels of Aß1-42, total tau and P-tau181p were significantly related to worsening of some motor and/or cognitive functions. The CSF level of O-αS showed no correlation with any motor and cognitive assessments or with CSF levels of the other proteins. CONCLUSION: CSF levels of αS are correlated with some clinical symptoms and CSF levels of other pathogenic proteins in drug-naïve PD patients. These correlations suggest a central role for interaction and aggregation of αS with Aß1-42, tau, and phosphorylated tau in the pathogenesis of PD. Although O-αS has been shown to have neurotoxic effects, CSF levels do not reflect clinical symptoms or levels of other proteins in cross-sectional assessment.

Longitudinal clinical and neuro-radiological findings in a patient with leukoencephalopathy with brain calcifications and cysts (Labrune syndrome).

Since she was 4 years old, the patient had exhibited frequent convulsive seizures, and she experienced severe headaches and depression in adulthood. At the age of 37 years, cerebral calcifications were detected, but she exhibited no cognitive or motor problems. She suffered a cerebral haemorrhage at 49 years old and experienced cognitive dysfunction, dysarthria, dysphagia, and left-hemiparesis as sequelae. After undergoing gastrostomy, she exhibited very slow cognitive deterioration associated with speech disturbance over more than 10 years. She also gradually developed limb spasticity with Babinski signs. Repeated computerised tomography scans revealed unexpected changes including 2 cysts that appeared separately after small haemorrhages, an intracerebral haemorrhage, and intra-cyst bleeding. These longitudinal scans also showed progressive ventricular dilatation and expansion of the leukoencephalopathy, but there were no apparent changes in the intracranial calcifications. Magnetic resonance imaging revealed numerous microbleeds, and magnetic resonance angiography revealed irregularity of the cerebral artery walls with stoppage. Her SNORD118 gene exhibited compound heteromutation of c.38C > G and c.116G > C on different alleles. She was finally diagnosed with leukoencephalopathy with brain calcifications and cysts (Labrune syndrome) at the age of 61 years. Past reports have suggested that diffuse cerebral microangiopathy underlies Labrune syndrome's pathogenesis, but we speculate that cerebral macroangiopathy may also underlie it.

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 Alzheimer's Disease Database, which is accessible at http://alzdb.bri.niigata-u.ac.jp/.

Cerebrospinal fluid levels of phosphorylated tau and Aß1-38/Aß1-40/Aß1-42 in Alzheimer's disease with PS1 mutations.

We studied seven cases of Alzheimer's disease (AD). Six of the patients had presenilin 1 (PS1) mutations (PS1AD). Three novel PS1 mutations (T99A, H131R and L219R) and three other missense mutations (M233L, H163R and V272A) were found in the PS1AD group. We measured the levels of phosphorylated tau (ptau-181, ptau-199) and Aß (Aß1-42, Aß1-40 and Aß1-38) in the cerebrospinal fluid (CSF) of PS1AD patients, early-onset sporadic AD (EOSAD), late-onset sporadic AD (LOSAD) and non-demented subjects (ND). The CSF levels of Aß1-42 in the three AD groups were significantly lower than those of the ND group (p < 0.0001). CSF levels of Aß1-42 in the PS1AD group were significantly lower than those in the two sporadic AD groups. The Aß1-40 and Aß1-38 levels in the CSF of the PS1AD group were significantly lower than those of the three other groups (p < 0.0001, respectively). The levels of Aß1-40, Aß1-38 and Aß1-42 in the CSF of the PS1AD group remained lower than those of the ND group for 4 years. Not only CSF Aß1-42, but also Aß1-40 and Aß1-38 decreased in the advanced stages of PS1AD.

SORL1 is genetically associated with neuropathologically characterized late-onset Alzheimer's disease.

SORL1 was shown to be genetically associated with late-onset Alzheimer's disease (LOAD) in a large-scale genome-wide association study (GWAS) involving clinically verified subjects. Here, we attempted to replicate the association of SORL1 in Japanese neuropathologically characterized brain donor subjects (LOAD, 213; control, 370) through a single-nucleotide polymorphism (SNP)-based genetic study involving 19 SNPs: 11 SNPs were selected from the initial study reported by Rogaeva et al. (2007), and the other eight were from our GWAS. Among these SNPs, five exhibited a significant association with LOAD after multiple test correction (p < 2.63E-03 [ = 0.05/19]), which was supported by means of multiple logistic regression analysis with adjustment for age, gender, and carrier status of the APOE ε4 allele. Three of these SNPs (rs985421, rs12364988 [Rogaeva's SNP 7], and rs4598682) were encompassed by a 5' linkage disequilibrium (LD) region, and the remaining two (rs3781834 and rs3781836) by a 3' LD region. Strong LD among SNPs was observed within each LD region, implying that there are two genomic regions showing association with LOAD in SORL1. Case-control haplotype analysis demonstrated that some haplotypes are associated with LOAD in both LD regions. Our replication study strongly supports the preceding evidence that SORL1 is likely one of the genes associated with LOAD.

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.

Genetic association study on in and around the APOE in late-onset Alzheimer disease in Japanese.

The epsilon4 allele of APOE is a well-characterized genetic risk factor for late-onset Alzheimer disease (LOAD). Nevertheless, using high-density single nucleotide polymorphisms (SNPs), there have only been a few studies involving genetic association and linkage disequilibrium (LD) analyses of in and around the APOE. Here, we report fine mapping of a genomic region (about 200 kb) including the APOE in Japanese using 260 SNPs (mean intermaker distance, 0.77 kb). A case-control study demonstrated that 36 of these SNPs exhibited significance after adjustment for multiple testing. These SNPs are located in a genomic region including four genes, PVRL2, TOMM40, APOE and APOC1. Recombination rate estimation revealed that the associated region is firmly sandwiched between two recombination hotspots. Strong LD between these SNPs was observed (mean |D'|=0.914). These data suggest that the three genes other than APOE, i.e. PVRL2, TOMM40 and APOC1, could also yield a predisposition to LOAD.

Mutational analysis in early-onset familial dementia in the Japanese population. The role of PSEN1 and MAPT R406W mutations.

BACKGROUND: Three major causative genes have been implicated as the cause of early-onset familial Alzheimer's disease (AD): the amyloid precursor protein gene (APP), presenilin-1 (PSEN1) and PSEN2. Although rare, a tau-related dementia with mutations in the microtubule-associated protein tau gene (MAPT) has been identified in patients showing clinical presentations similar to those of AD. METHODS: We performed mutational analysis of APP, PSEN1, PSEN2, and MAPT in 10 Japanese families with early-onset dementia clinically diagnosed as probable Alzheimer's disease. RESULTS: In 4 index patients, we identified 4 missense PSEN1 mutations, namely, L286V, G378E, L381V, and L392V. The mean age at onset in the patients with PSEN1 mutations was 39 years. In 2 families, we found the R406W mutation in MAPT. The mean age at onset of the patients carrying the R406W mutation was 52 years, and they presented with the peculiar AD-like phenotype without apparent behavioral or language problems. CONCLUSION: These observations suggest that although PSEN1 mutations are the most frequent cause, the MAPT R406W mutation is an important cause of early-onset familial dementia clinically diagnosed as AD. Differentiation of patients with the MAPT mutation from AD patients by genetic testing would be meaningful, considering that a different therapeutic approach should be applied.

Dynamin-binding protein gene on chromosome 10q is associated with late-onset Alzheimer's disease.

The apolipoprotein E (APOE) gene has been consistently shown to be a major genetic risk factor; however, all cases of Alzheimer's disease (AD) cannot be attributed to the epsilon4 variant of APOE, because about half of AD patients have the APOE-epsilon3*3 genotype. To identify an additional genetic risk factor(s), we performed large-scale single nucleotide polymorphism (SNP)-based association analysis of 1526 late-onset AD patients and 1666 control subjects in a Japanese population. We prepared two independent sets consisting of exploratory and validation samples, respectively, with only the APOE-epsilon3*3 genotype, and first carried out genotyping for the exploratory set with 1206 SNPs in the region between 60 and 107 Mb on chromosome 10q that is implicated by linkage studies as containing an AD susceptibility locus. Thirty-five SNPs that showed significant values (P<0.01) were followed-up to detect any association with the validation samples. Finally, six SNPs exhibited replicated significant associations (P=0.000035-0.00048) on meta-analysis of both sets. These SNPs were clustered in a locus spanning 220 kb at genomic position 101 Mb, and three of the six SNPs were located in the dynamin-binding protein (DNMBP) gene. Quantitative real-time RT-PCR analysis demonstrated that neuropathologically confirmed AD brains exhibit a significant reduction of DNMBP mRNA compared with age-matched ones (P<0.0169). Thus, we confirmed the association of DNMBP with AD individuals with the APOE-epsilon3*3 genotype or lacking the epsilon4 allele, and DNMBP may be one of the susceptibility genes for AD.