Brain communications最新文献

Brain serotonin dysregulation is associated with dementia and neuropsychiatric symptomology. However, the prognostic utility of circulating serotonin levels in detecting features of prodromal dementia including functional decline, cognitive impairment, mild behavioural impairment and brain atrophy remains unclear. In this prospective study of memory clinic subjects followed-up for ≤5 years, dementia-free subjects, classified as having no cognitive impairment or cognitive impairment, no dementia at baseline, underwent annual neuropsychological assessments including Montreal Cognitive Assessment, Global Cognition Z-scores and Clinical Dementia Rating Scale Global Scores (where a ≥ 0.5 increment from baseline denotes functional decline). Mild behavioural impairment was measured using baseline and annual Neuropsychiatric Inventory assessments, while brain atrophy was evaluated using cortical and medial temporal atrophy scores from baseline MRI scans. Baseline serum serotonin was then associated with the neuropsychological and neuroimaging measures cross-sectionally and longitudinally. Furthermore, associations of serum serotonin with cross-sectional brain atrophy scores were studied. Of the 191 elderly subjects included in the study, 63 (33.0%) had no cognitive impairment while 128 (67.0%) had cognitive impairment, no dementia. Fourteen subjects (9.0%) showed baseline mild behavioural impairment. Compared with the highest tertile, subjects within the lowest tertile of serotonin had greater Cortical Atrophy scores (adjusted odds ratio = 2.54, 95% confidence interval=1.22-5.30, P = 0.013). Serotonin levels were not significantly associated with cross-sectional neuropsychological or mild behavioural impairment scores (all P > 0.05). Of the 181 subjects with longitudinal cognitive follow-up (median duration 60.0 months), 56 (30.9%) developed functional decline, while incident mild behavioural impairment occurred in 26/119 (21.8%) subjects. Compared with the highest tertile, lower serotonin levels were associated with higher hazards of functional decline (lowest tertile: adjusted hazards ratio = 2.15, 95% confidence interval = 1.04-4.44, P = 0.039), and incident mild behavioural impairment (lowest tertile: adjusted hazards ratio = 3.82, 95% confidence interval = 1.13-12.87, P = 0.031, middle tertile: adjusted hazards ratio = 3.56, 95% confidence interval =1.05-12.15, P = 0.042). The association between the lowest serotonin tertile and functional decline was mediated via its effect on incident mild behavioural impairment (adjusted odds ratio = 3.96, 95% confidence interval = 1.15-13.61, P = 0.029). In conclusion, low circulating serotonin may be associated with cortical atrophy at baseline, as well as act as an early prognostic marker for functional decline and mild behavioural impairment in elderly, dementia-free subjects.

Primary progressive multiple sclerosis (PPMS) affects 10-15% of multiple sclerosis patients and presents significant variability in the rate of disability progression. Identifying key biological features and patients at higher risk for fast progression is crucial to develop and optimize treatment strategies. Peripheral blood cell transcriptome has the potential to provide valuable information to predict patients' outcomes. In this study, we utilized a machine learning framework applied to the baseline blood transcriptional profiles and brain MRI radiological enumerations to develop prognostic models. These models aim to identify PPMS patients likely to experience significant disease progression and who could benefit from early treatment intervention. RNA-sequence analysis was performed on total RNA extracted from peripheral blood mononuclear cells of PPMS patients in the placebo arm of the ORATORIO clinical trial (NCT01412333), using Illumina NovaSeq S2. Cross-validation algorithms from Partek Genome Suite (www.partek.com) were applied to predict disability progression and brain volume loss over 120 weeks. For disability progression prediction, we analysed blood RNA samples from 135 PPMS patients (61 females and 74 males) with a mean ± standard error age of 44.0 ± 0.7 years, disease duration of 5.9 ± 0.32 years and a median baseline Expanded Disability Status Scale (EDSS) score of 4.3 (range 3.5-6.5). Over the 120-week study, 39.3% (53/135) of patients reached the disability progression end-point, with an average EDSS score increase of 1.3 ± 0.16. For brain volume loss prediction, blood RNA samples from 94 PPMS patients (41 females and 53 males), mean ± standard error age of 43.7 ± 0.7 years and a median baseline EDSS of 4.0 (range 3.0-6.5) were used. Sixty-seven per cent (63/94) experienced significant brain volume loss. For the prediction of disability progression, we developed a two-level procedure. In the first level, a 10-gene predictor achieved a classification accuracy of 70.9 ± 4.5% in identifying patients reaching the disability end-point within 120 weeks. In the second level, a four-gene classifier distinguished between fast and slow disability progression with a 506-day cut-off, achieving 74.1 ± 5.2% accuracy. For brain volume loss prediction, a 12-gene classifier reached an accuracy of 70.2 ± 6.7%, which improved to 74.1 ± 5.2% when combined with baseline brain MRI measurements. In conclusion, our study demonstrates that blood transcriptome data, alone or combined with baseline brain MRI metrics, can effectively predict disability progression and brain volume loss in PPMS patients.

Blood-based biomarkers have been revolutionizing the detection, diagnosis and screening of Alzheimer's disease. Specifically, phosphorylated-tau variants (p-tau₁₈₁, p-tau₂₁₇ and p-tau₂₃₁) are promising biomarkers for identifying Alzheimer's disease pathology. Antibody-based assays such as single molecule arrays immunoassays are powerful tools to investigate pathological changes indicated by blood-based biomarkers and have been studied extensively in the Alzheimer's disease research field. A novel proteomic technology-NUcleic acid Linked Immuno-Sandwich Assay (NULISA)-was developed to improve the sensitivity of traditional proximity ligation assays and offer a comprehensive outlook for 120 protein biomarkers in neurodegenerative diseases. Due to the relative novelty of the NULISA technology in quantifying Alzheimer's disease biomarkers, validation through comparisons with more established methods is required. The main objective of the current study was to determine the capability of p-tau variants quantified using NULISA for identifying abnormal amyloid-β and tau pathology. We assessed 397 participants [mean (standard deviation) age, 64.8 (15.7) years; 244 females (61.5%) and 153 males (38.5%)] from the Translational Biomarkers in Aging and Dementia (TRIAD) cohort where participants had plasma measurements of p-tau₁₈₁, p-tau₂₁₇ and p-tau₂₃₁ from NULISA and single molecule arrays immunoassays. Participants also underwent neuroimaging assessments, including structural MRI, amyloid-PET and tau-PET. Our findings suggest an excellent agreement between plasma p-tau variants quantified using NULISA and single molecule arrays immunoassays. Plasma p-tau₂₁₇ measured with NULISA shows excellent discriminative accuracy for abnormal amyloid-PET (area under the receiver operating characteristic curve = 0.918, 95% confidence interval = 0.883 to 0.953, P < 0.0001) and tau-PET (area under the receiver operating characteristic curve = 0.939; 95% confidence interval = 0.909 to 0.969, P < 0.0001). It also presents the capability for differentiating tau-PET staging. Validation of the NULISA-measured plasma biomarkers adds to the current analytical methods for Alzheimer's disease diagnosis, screening and staging and could potentially expedite the development of a blood-based biomarker panel.

Atrial fibrillation and heart failure have both been suggested to increase stroke and dementia risk. However, in observational studies, reversed causation and unmeasured confounding may occur. To mitigate these issues, this study aims to investigate if higher genetic risk for atrial fibrillation and heart failure increases dementia and stroke risk. Data were obtained from the population-based Gothenburg H70 Birth Cohort Studies in Sweden. Participants (N = 984) were born in 1930 with baseline examinations at age 70, 75, 79 or 85 and follow-ups until age 88-89. Polygenic risk scores at the 5 × 10^-8, 1 × 10^-5, 1 × 10^-3 and 1 × 10^-1 thresholds were generated for atrial fibrillation and heart failure. Stroke was diagnosed based on self-reports, close-informant interviews, and the National Patient Register. Dementia was diagnosed based on neuropsychiatric examinations, close-informant interviews, and the National Patient Register. Cox regression analyses were performed, adjusted for sex, age at baseline and the first five principal components to correct for population stratification. Those within the highest atrial fibrillation-polygenic risk score tertile had a 1.5 (95% CI 1.09-2.03) increased risk of dementia (at the 1 × 10^-5 threshold) and a 1.5 (95% CI 1.07-2.03) increased risk of stroke (at the 1 × 10^-3 threshold) compared to the lowest tertile. Those within the highest heart failure-polygenic risk score tertile had a 1.6 (95% CI 1.19-2.27) increased risk of dementia (at the 5 × 10^-8 threshold), but no increased risk of stroke (HR 1.2; 95% CI 0.83-1.60 at the 1 × 10^-5 threshold), compared to the lowest tertile. When analysing the polygenic risk scores as a continuous variable, the associations were in the same direction, although weaker. This study, investigating genetic risk of atrial fibrillation and heart failure in relation to stroke and dementia, supports the increasing body of evidence suggesting that atrial fibrillation is associated with both stroke and dementia risk. Whether heart failure increases dementia risk is less established, but the present study found that genetic risk of heart failure increased dementia risk. The finding that genetic risk for heart failure did not increase stroke risk needs to be interpreted with caution, as it may be due to a lack of statistical power. There are guidelines on how to best treat atrial fibrillation to prevent stroke, but more knowledge is needed on how to treat atrial fibrillation and heart failure to prevent dementia.

[This retracts the article DOI: 10.1093/braincomms/fcae077.].

Parkinson's disease is primarily marked by mitochondrial dysfunction and metabolic abnormalities. We recently reported that the combined metabolic activators improved the immunohistochemical parameters and behavioural functions in Parkinson's disease and Alzheimer's disease animal models and the cognitive functions in Alzheimer's disease patients. These metabolic activators serve as the precursors of nicotinamide adenine dinucleotide and glutathione, and they can be used to activate mitochondrial metabolism and eventually treat mitochondrial dysfunction. Here, we designed a randomized, double-blinded, placebo-controlled phase II study in Parkinson's disease patients with 84 days combined metabolic activator administration. A single dose of combined metabolic activator contains L-serine (12.35 g), N-acetyl-L-cysteine (2.55 g), nicotinamide riboside (1 g) and L-carnitine tartrate (3.73 g). Patients were administered either one dose of combined metabolic activator or a placebo daily for the initial 28 days, followed by twice-daily dosing for the next 56 days. The main goal of the study was to evaluate the clinical impact on motor functions using the Unified Parkinson's Disease Rating Scale and to determine the safety and tolerability of combined metabolic activator. A secondary objective was to assess cognitive functions utilizing the Montreal Cognitive Assessment and to analyse brain activity through functional MRI. We also performed comprehensive plasma metabolomics and proteomics analysis for detailed characterization of Parkinson's disease patients who participated in the study. Although no improvement in motor functions was observed, cognitive function was shown to be significantly improved (P < 0.0000) in Parkinson's disease patients treated with the combined metabolic activator group over 84 days, whereas no such improvement was noted in the placebo group (P > 0.05). Moreover, a significant reduction (P = 0.001) in Montreal Cognitive Assessment scores was observed in the combined metabolic activator group, with no decline (P > 0.05) in the placebo group among severe Parkinson's disease patients with lower baseline Montreal Cognitive Assessment scores. We showed that improvement in cognition was associated with critical brain network alterations based on functional MRI analysis, especially relevant to areas with cognitive functions in the brain. Finally, through a comprehensive multi-omics analysis, we elucidated the molecular mechanisms underlying cognitive improvements observed in Parkinson's disease patients. Our results show that combined metabolic activator administration leads to enhanced cognitive function and improved metabolic health in Parkinson's disease patients as recently shown in Alzheimer's disease patients. The trial was registered in ClinicalTrials.gov NCT04044131 (17 July 2019, https://clinicaltrials.gov/ct2/show/NCT04044131).

Dominantly inherited intronic GAA repeat expansions in the fibroblast growth factor 14 gene have recently been shown to cause spinocerebellar ataxia 27B. Currently, the pathogenic threshold of (GAA)_≥300 repeat units is considered highly penetrant, while (GAA)_250-299 is likely pathogenic with reduced penetrance. This study investigated the frequency of the GAA repeat expansion and the phenotypic profile in a Cypriot cohort with unresolved late-onset cerebellar ataxia. We analysed this trinucleotide repeat in 155 patients with late-onset cerebellar ataxia and 227 non-neurological disease controls. The repeat locus was examined by long-range PCR followed by fragment analysis using capillary electrophoresis, agarose gel electrophoresis and automated electrophoresis. A comprehensive comparison of all three electrophoresis techniques was conducted. Additionally, bidirectional repeat-primed PCRs and Sanger sequencing were carried out to confirm the absence of any interruptions or non-GAA motifs in the expanded alleles. The (GAA)_≥250 repeat expansion was present in 12 (7.7%) patients. The average age at disease onset was 60 ± 13.5 years. The earliest age of onset was observed in a patient with a (GAA)₂₈₇ repeat expansion, with ataxia symptoms appearing at 25 years of age. All patients with spinocerebellar ataxia 27B displayed symptoms of gait and appendicular ataxia. Nystagmus was observed in 41.7% of the patients, while 58.3% exhibited dysarthria. Our findings indicate that spinocerebellar ataxia 27B represents the predominant aetiology of autosomal dominant cerebellar ataxia in the Cypriot population, as this is the first dominant repeat expansion ataxia type detected in this population. Given our results and existing research, we propose including fibroblast growth factor 14 GAA repeat expansion testing as a first-tier genetic diagnostic approach for patients with late-onset cerebellar ataxia.

Former studies have established that individuals with a cochlear implant (CI) for treating single-sided deafness experience improved speech processing after implantation. However, it is not clear how each ear contributes separately to improve speech perception over time at the behavioural and neural level. In this longitudinal EEG study with four different time points, we measured neural activity in response to various temporally and spectrally degraded spoken words presented monaurally to the CI and non-CI ears (5 left and 5 right ears) in 10 single-sided CI users and 10 age- and sex-matched individuals with normal hearing. Subjective comprehension ratings for each word were also recorded. Data from single-sided CI participants were collected pre-CI implantation, and at 3, 6 and 12 months after implantation. We conducted a time-resolved representational similarity analysis on the EEG data to quantify whether and how neural patterns became more similar to those of normal hearing individuals. At 6 months after implantation, the speech comprehension ratings for the degraded words improved in both ears. Notably, the improvement was more pronounced for the non-CI ears than the CI ears. Furthermore, the enhancement in the non-CI ears was paralleled by increased similarity to neural representational patterns of the normal hearing control group. The maximum of this effect coincided with peak decoding accuracy for spoken-word comprehension (600-1200 ms after stimulus onset). The present data demonstrate that cortical processing gradually normalizes within months after CI implantation for speech presented to the non-CI ear. CI enables the deaf ear to provide afferent input, which, according to our results, complements the input of the non-CI ear, gradually improving its function. These novel findings underscore the feasibility of tracking neural recovery after auditory input restoration using advanced multivariate analysis methods, such as representational similarity analysis.