Clinical features of dementia with lewy bodies in 35 Chinese patients

Review on anti-alzheimer drug development: approaches, challenges and perspectives

Alzheimer is an irreversible progressive neurodegenerative disease that causes failure of cerebral neurons and disability of the affected person to practice normal daily life activities. There is no concrete evidence to identify the exact reason behind the disease, so several relevant hypotheses emerged, highlighting many possible therapeutic targets, such as acetylcholinesterase, cholinergic receptors, N-methyl d-aspartate receptors, phosphodiesterase, amyloid β protein, protein phosphatase 2A, glycogen synthase kinase-3 beta, β-secretase, γ-secretase, α-secretase, serotonergic receptors, glutaminyl cyclase, tumor necrosis factor-α, γ-aminobutyric acid receptors, and mitochondria. All of these targets have been involved in the design of new potential drugs. An extensive number of these drugs have been studied in clinical trials. However, only galantamine, donepezil, and rivastigmine (ChEIs), memantine (NMDA antagonist), and aducanumab and lecanemab (selective anti-Aβ monoclonal antibodies) have been approved for AD treatment. Many drugs failed in the clinical trials to such an extent that questions have been posed about the significance of some of the aforementioned targets. On the contrary, the data of other drugs were promising and shed light on the significance of their targets for the development of new potent anti-alzheimer drugs.

Tracking the structure and sentiment of vaccination discussions on Mumsnet

Vaccination is one of the most impactful healthcare interventions in terms of lives saved at a given cost, leading the anti-vaccination movement to be identified as one of the top 10 threats to global health in 2019 by the World Health Organization. This issue increased in importance during the COVID-19 pandemic where, despite good overall adherence to vaccination, specific communities still showed high rates of refusal. Online social media has been identified as a breeding ground for anti-vaccination discussions. In this work, we study how vaccination discussions are conducted in the discussion forum of Mumsnet, a UK-based website aimed at parents. By representing vaccination discussions as networks of social interactions, we can apply techniques from network analysis to characterize these discussions, namely network comparison, a task aimed at quantifying similarities and differences between networks. Using network comparison based on graphlets-small connected network subgraphs-we show how the topological structure of vaccination discussions on Mumsnet differs over time, in particular before and after COVID-19. We also perform sentiment analysis on the content of the discussions and show how the sentiment toward vaccinations changes over time. Our results highlight an association between differences in network structure and changes to sentiment, demonstrating how network comparison can be used as a tool to guide and enhance the conclusions from sentiment analysis.

Aluminum neurotoxicity and autophagy: a mechanistic view

It is strongly believed that aluminum is one of the insalubrious agents because of its neurotoxicity effects and influences on amyloid β (Aβ) production and tau protein hyperphosphorylation following oxidative stress, as one of the initial events in neurotoxicity. The autophagy process plays a considerable role in neurons in preserving intracellular homeostasis and recycling organelles and proteins, especially Aβ and soluble tau. Thus, autophagy is suggested to ameliorate aluminum neurotoxicity effects, and dysfunction of this process can lead to an increase in detrimental proteins. However, the relationship between aluminum neurotoxicity and autophagy dysregulation in some dimensions remains unclear. In the present review, we want to give an overview of the autophagy roles in aluminum neurotoxicity and how dysregulation of autophagy can affect aluminum neurotoxicity.

Inhibition of Nwd1 activity attenuates neuronal hyperexcitability and GluN2B phosphorylation in the hippocampus

BACKGROUND

NACHT and WD repeat domain-containing protein 1 (Nwd1) is a member of the innate immune protein subfamily. Nwd1 contributes to the androgen receptor signaling pathway and is involved in axonal growth. However, the mechanisms that underlie pathophysiological dysfunction in seizures remain unclear.

METHODS

Biochemical methods were used to assess Nwd1 expression and localization in a mouse model of kainic acid (KA)-induced acute seizures and temporal lobe epilepsy (TLE) patients. Electrophysiological recordings were used to measure the role of Nwd1 in regulating synaptic transmission and neuronal hyperexcitability in a model of magnesium-free-induced seizure in vitro. Behavioral experiments were performed, and seizure-induced pathological changes were evaluated in a KA-induced seizure model in vivo. GluN2B expression was measured and its correlation with Tyr1472-GluN2B phosphorylation was analyzed in primary hippocampal neurons.

FINDINGS

We demonstrated high protein levels of Nwd1 in brain tissues obtained from mice with acute seizures and TLE patients. Silencing Nwd1 in mice using an adeno-associated virus (AAV) profoundly suppressed neuronal hyperexcitability and the occurrence of acute seizures, which may have been caused by reducing GluN2B-containing NMDA receptor-dependent glutamatergic synaptic transmission. Moreover, the decreased activation of Nwd1 reduced GluN2B expression and the phosphorylation of the GluN2B subunit at Tyr1472.

INTERPRETATION

Here, we report a previously unrecognized but important role of Nwd1 in seizure models in vitro and in vivo, i.e., modulating the phosphorylation of the GluN2B subunit at Tyr1472 and regulating neuronal hyperexcitability. Meanwhile, our findings may provide a therapeutic strategy for the treatment of epilepsy or other hyperexcitability-related neurological disorders. FUND: The funders have not participated in the study design, data collection, data analysis, interpretation, or writing of the report.

Clinical and neuroimaging characteristics of Chinese dementia with Lewy bodies

Dementia with Lewy bodies (DLB) is the second most common subtype of degenerative dementia. To our knowledge, available information about the clinical features of DLB in China remains limited. Our study therefore aimed to address this issue. Thirty-seven Chinese patients with probable DLB were recruited for this study. All subjects underwent neuropsychological assessment by trained neurologists, as well as undergoing MRI, ¹¹C-PIB PET scans for Aβ deposition and ¹⁸F-FDG PET scans for regional cerebral glucose metabolism. Our results showed that the gender ratio of patients was 16:21 (F:M). The mean age of onset was 69.5 ± 9.0 years and the mean age at diagnosis was 71.8 ± 9.1 years. At diagnosis, the prevalence of three core clinical features of DLB was: 64.9% for fluctuating cognition, 73.0% for visual hallucinations and 62.2% for parkinsonism. The result from ¹¹C-PiB PET and ¹⁸F-FDG PET scans confirmed Aβ deposition in the cortex and demonstrated hypometabolism in the bilateral temporoparietooccipital region, the frontal lobe, the insular lobe, and the posterior cingulate, precuneus and caudate nuclei. Our study elucidated the clinical features of Chinese DLB patients, and will improve the understanding and the early diagnosis of DLB in Chinese patients.

Insight of brain degenerative protein modifications in the pathology of neurodegeneration and dementia by proteomic profiling

Dementia is a syndrome associated with a wide range of clinical features including progressive cognitive decline and patient inability to self-care. Due to rapidly increasing prevalence in aging society, dementia now confers a major economic, social, and healthcare burden throughout the world, and has therefore been identified as a public health priority by the World Health Organization. Previous studies have established dementia as a 'proteinopathy' caused by detrimental changes in brain protein structure and function that promote misfolding, aggregation, and deposition as insoluble amyloid plaques. Despite clear evidence that pathological cognitive decline is associated with degenerative protein modifications (DPMs) arising from spontaneous chemical modifications to amino acid side chains, the molecular mechanisms that promote brain DPMs formation remain poorly understood. However, the technical challenges associated with DPM analysis have recently become tractable due to powerful new proteomic techniques that facilitate detailed analysis of brain tissue damage over time. Recent studies have identified that neurodegenerative diseases are associated with the dysregulation of critical repair enzymes, as well as the misfolding, aggregation and accumulation of modified brain proteins. Future studies will further elucidate the mechanisms underlying dementia pathogenesis via the quantitative profiling of the human brain proteome and associated DPMs in distinct phases and subtypes of disease. This review summarizes recent developments in quantitative proteomic technologies, describes how these techniques have been applied to the study of dementia-linked changes in brain protein structure and function, and briefly outlines how these findings might be translated into novel clinical applications for dementia patients. In this review, only spontaneous protein modifications such as deamidation, oxidation, nitration glycation and carbamylation are reviewed and discussed.

Comparisons of clinical symptoms in biomarker-confirmed Alzheimer's disease, dementia with Lewy bodies, and frontotemporal dementia patients in a local memory clinic

BACKGROUND

There has been no previous Chinese study that differentiated the clinical symptoms among biomarker-confirmed Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD). The objective of this study was to compare the cognitive, behavioural, and neuropsychiatric symptoms in biomarker-confirmed AD, DLB, and FTD patients.

METHODS

We recruited 30 patients (14 AD, 7 DLB, 9 FTD) who presented to the memory clinic at Queen Mary Hospital from 1 January 2007 to 31 December 2013. AD was diagnosed according to the National Institution of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association criteria with cerebrospinal fluid biomarkers (tau, phosphorylated tau, and amyloid β-42) fulfilling locally determined cut-off values for AD. DLB was diagnosed based on the McKeith diagnostic criteria. The behavioural variant of FTD was diagnosed based on the revised diagnostic criteria proposed by the International bvFTD Criteria Consortium, and language variant FTD was diagnosed based on the latest published criteria. In addition, patients with DLB and FTD had typical imaging features on single-photon emission computed tomography or (18) fludeoxyglucose-positron emission tomography, either with or without Pittsburgh Compound B imaging, which supported their diagnoses. Data on patient characteristics including demographics, presenting clinical features, Mini-Mental State Examination, clinical dementia ratings, and neuropsychiatry inventory scores were collected.

RESULTS

There were no differences in age, education level, dementia severity, and duration of symptoms before presentation among the three subgroups of patients. All patients had amnesia symptoms, which were not statistically significant. Apraxia was most common in AD. While 83% of the patients were affected by behavioural and neuropsychiatric symptoms of dementia, behavioural disinhibition and decline in executive function were most common in FTD patients. Recurrent hallucinations, fluctuation of consciousness, parkinsonism, and rapid eye movement sleep behaviour disorder were most common in DLB.

CONCLUSION

Memory impairment and apathy are not useful discriminative symptoms in diagnosing AD, DLB, and FTD. Apraxia favours AD. Hallucinations, particularly well-formed visual hallucinations, favour DLB. Overall, behavioural and neuropsychiatric symptoms of dementia symptoms are common among the three groups of dementia patients.

Démence à corps de Lewy et psychiatrie

Introduction

La maladie à corps de Lewy est la seconde cause de démence. Il persiste malgré cela de fréquentes errances diagnostiques, notamment lors de manifestations initiales psychiatriques.

Méthodes

Nous présentons le cas clinique de M F., 60 ans, hospitalisé pour la seconde fois en psychiatrie suite à des troubles du comportement à domicile. Il avait été pris en charge 3 ans auparavant en ambulatoire pour épisode dépressif majeur avec éléments psychotiques , traité par paroxetine et rispéridone. Il a été dans un second temps hospitalisé devant un tableau hypomaniaque, ayant abouti à un diagnostic de trouble bipolaire et la mise en place d’un traitement par valpromide. Aucun bilan neurologique ou neuropsychologique n’avait été effectué.

Résultats

Au cours de l’hospitalisation, le patient a présenté des fluctuations cognitives, un parkinsonisme, des idées délirantes systématisées à thématique de persécution et une hypersensibilité aux neuroleptiques. Ont été également notés une anosognosie, des troubles du sommeil , des éléments maniaques atypiques avec des achats compulsifs et une désinhibition. Le traitement thymorégulateur initial associé à la loxapine a été inefficace et mal toléré. L’arrêt de l’antipsychotique a permis une nette amélioration clinique. Un traitement par valproate a été secondairement initié, permettant un bon apaisement comportemental. La biologie, le scanner cérébral et l’IRM cérébrale ont éliminé les étiologies organiques courantes. Le bilan neuropsychologique a orienté le diagnostic (troubles des fonctions visuo-spatiales , de l’attention et des fonctions exécutives) vers une probable maladie à corps de Lewy.

Discussion

Les éléments cliniques peuvent être en accord avec un trouble bipolaire. Mais le terrain, l’anamnèse, les signes atypiques, la réponse aux différentes thérapeutiques et le bilan neuropsychologique orientent vers une maladie à corps de Lewy. On note donc l’importance d’associer au recueil clinique un bilan neurologique et neuropsychologique en pratique courante.