Somatic genomic changes in single Alzheimer's disease neurons.

Dementia in Alzheimer's disease progresses alongside neurodegeneration1-4, but the specific events that cause neuronal dysfunction and death remain poorly understood. During normal ageing, neurons progressively accumulate somatic mutations5 at rates similar to those of dividing cells6,7 which suggests that genetic factors, environmental exposures or disease states might influence this accumulation5. Here we analysed single-cell whole-genome sequencing data from 319 neurons from the prefrontal cortex and hippocampus of individuals with Alzheimer's disease and neurotypical control individuals. We found that somatic DNA alterations increase in individuals with Alzheimer's disease, with distinct molecular patterns. Normal neurons accumulate mutations primarily in an age-related pattern (signature A), which closely resembles 'clock-like' mutational signatures that have been previously described in healthy and cancerous cells6-10. In neurons affected by Alzheimer's disease, additional DNA alterations are driven by distinct processes (signature C) that highlight C>A and other specific nucleotide changes. These changes potentially implicate nucleotide oxidation4,11, which we show is increased in Alzheimer's-disease-affected neurons in situ. Expressed genes exhibit signature-specific damage, and mutations show a transcriptional strand bias, which suggests that transcription-coupled nucleotide excision repair has a role in the generation of mutations. The alterations in Alzheimer's disease affect coding exons and are predicted to create dysfunctional genetic knockout cells and proteostatic stress. Our results suggest that known pathogenic mechanisms in Alzheimer's disease may lead to genomic damage to neurons that can progressively impair function. The aberrant accumulation of DNA alterations in neurodegeneration provides insight into the cascade of molecular and cellular events that occurs in the development of Alzheimer's disease.

Attitudes toward epilepsy among medical staffs in basic-level hospitals from southern China.

OBJECTIVE: The objectives of the study were to assess attitudes toward epilepsy among medical staffs from basic-level hospitals in southern China and identify significant predictive factors for future stigma reduction interventions. METHODS: The Public Attitudes Toward Epilepsy (PATE) scale, a two dimensional 14-item scale addressing two major domains: general domain and personal domain, was administered to 448 medical staffs from basic-level hospitals in southern China. Positively stated items in the PATE scale were reversely scored; in this case, a higher score would indicate a more negative attitude. Also, we compared the overall score and per-item scores of the medical staffs versus those of the general population reported in the previous studies using the same scale. RESULTS: The cumulative score of the medical staffs was 41.65 ±â€¯6.99, which is significantly lower as compared with 51.38 ±â€¯6.80 of the general population (t (645) = -16.473, p < 0.001). The general average score (t (645) = -16.473, p < 0.001) and the mean score in the general domain (t (645) = -22.573, p < 0.001) of the PATE scale were both significantly lower in the medical staffs compared with the general population, whereas there was no significant difference between the two groups in the personal domain (t(645) = -0.180, p = 0.857). Age or years in clinical practice, specialty, and title had a significant impact on both the general domain and personal domain. Residence was the only factor found affecting the medical staffs' attitudes toward epilepsy in the personal domain but not in the general domain. CONCLUSION: Medical staffs from basic-level hospitals in southern China demonstrate significant positive attitudes toward people with epilepsy in general aspects when compared with the general population. However, they still showed negative and conservative attitudes when it comes to the personal domain. Future strategies for stigma-reducing public interventions could focus on increasing better understanding of epilepsy among medical staffs in basic-level hospitals in China.

Prevalence and predictors of seizure clusters: A prospective observational study of adult patients with epilepsy.

OBJECTIVE: The purpose of this prospective observational study was to describe the prevalence and adverse outcomes associated with seizure clusters (defined as ≥2 seizures in a 6-hour period) in a large sample of adult patients with a range of epilepsy severities and to identify clinical characteristics predictive of clustering. METHODS: Patients maintained a seizure diary and were contacted monthly to verify compliance and data accuracy. Logistic regression models were utilized to test associations between individual patient demographic/clinical characteristics and seizure clustering. Fisher's exact test was utilized to test associations between rescue medication use and adverse seizure-related outcomes. RESULTS: A total of 300 patients were followed prospectively for one year; 247 patients qualified for final analysis. Six-hour seizure clusters occurred in 45.8% of patients with active epilepsy at enrollment, including 62.7% of those with prior day-clusters and 30.0% of those without prior day-clusters. The odds of clustering were markedly greater among patients who reported a higher seizure frequency (>4 seizures per year vs. 1-4 seizures per year) (adjusted odds ratio (OR): 8.9; 95% confidence interval (CI): 3.2-24.6; p < 0.0001) and among patients with prior day-clusters (adjusted OR: 11.0; 95% CI: 1.2-104.2; p = 0.036). Rescue medication use was associated with significantly fewer injuries and emergency department visits, but rescue medication was underutilized. CONCLUSIONS: Seizure clusters are common, occurring in nearly half of adult patients with active epilepsy followed prospectively over one year, and are more frequent in those with higher seizure frequencies and prior day-clusters. Although underutilized, rescue medication was associated with fewer injuries and emergency department visit.

Seizures and Sleep in the Thalamus: Focal Limbic Seizures Show Divergent Activity Patterns in Different Thalamic Nuclei.

The thalamus plays diverse roles in cortical-subcortical brain activity patterns. Recent work suggests that focal temporal lobe seizures depress subcortical arousal systems and convert cortical activity into a pattern resembling slow-wave sleep. The potential simultaneous and paradoxical role of the thalamus in both limbic seizure propagation, and in sleep-like cortical rhythms has not been investigated. We recorded neuronal activity from the central lateral (CL), anterior (ANT), and ventral posteromedial (VPM) nuclei of the thalamus in an established female rat model of focal limbic seizures. We found that population firing of neurons in CL decreased during seizures while the cortex exhibited slow waves. In contrast, ANT showed a trend toward increased neuronal firing compatible with polyspike seizure discharges seen in the hippocampus. Meanwhile, VPM exhibited a remarkable increase in sleep spindles during focal seizures. Single-unit juxtacellular recordings from CL demonstrated reduced overall firing rates, but a switch in firing pattern from single spikes to burst firing during seizures. These findings suggest that different thalamic nuclei play very different roles in focal limbic seizures. While limbic nuclei, such as ANT, appear to participate directly in seizure propagation, arousal nuclei, such as CL, may contribute to depressed cortical function, whereas sleep spindles in relay nuclei, such as VPM, may interrupt thalamocortical information flow. These combined effects could be critical for controlling both seizure severity and impairment of consciousness. Further understanding of differential effects of seizures on different thalamocortical networks may lead to improved treatments directly targeting these modes of impaired function.SIGNIFICANCE STATEMENT Temporal lobe epilepsy has a major negative impact on quality of life. Previous work suggests that the thalamus plays a critical role in thalamocortical network modulation and subcortical arousal maintenance, but its precise seizure-associated functions are not known. We recorded neuronal activity in three different thalamic regions and found divergent activity patterns, which may respectively participate in seizure propagation, impaired level of conscious arousal, and altered relay of information to the cortex during focal limbic seizures. These very different activity patterns within the thalamus may help explain why focal temporal lobe seizures often disrupt widespread network function, and can help guide future treatments aimed at restoring normal thalamocortical network activity and cognition.

Validation of the Chinese version of public attitudes toward epilepsy scale in Mainland China.

PURPOSE: Epilepsy is a significant yet seriously underappreciated public health issue in Mainland China. The stigma and discrimination toward people with epilepsy (PWE) and their families are especially severe in China based on cultural misconceptions which cause tremendous psychological, economic and social burdens. It is imperative to formulate a targeted public intervention to eliminate knowledge gaps and correct these misconceptions of epilepsy. However, to date, the essential tools that may drive such an intervention by measuring the public perspective on PWEs is lacking in China. The goal of this study is to test the reliability and validity of a Simplified Chinese version of the "Public Attitude Toward Epilepsy" scale (PATE) in Mainland China which can be used to understand the content and identify the possible sources of stigma to better inform the design and focus of future stigma reduction interventions. METHODS: The standard procedure of cross-cultural adaptation was used in the translation process. Subjects from different economic and social backgrounds were enrolled by convenience sampling in central China. Exploratory factor analysis and confirmatory factor analysis were used to check the underlying factor structure of the items. Furthermore, Cronbach's alpha was utilized to assess internal consistency. RESULTS: 199 respondents were included in the final analysis. Content validity of this Chinese PATE was assessed to be adequate for assessing public attitudes toward epilepsy among the mainland Chinese. Two factors were extracted from the data by exploratory factor analysis; confirmatory factor analysis further confirmed good consistency of theoretical constructs between the original Public Attitudes Toward Epilepsy scale and our Chinese PATE. Our Chinese PATE presented excellent internal consistency (α=0.853-0.909). CONCLUSION: This version of the Chinese PATE showed acceptable psychometric properties, indicating that it can be implemented in surveying public attitudes toward epilepsy in Mainland China.

HGFA Is an Injury-Regulated Systemic Factor that Induces the Transition of Stem Cells into GAlert.

The activation of quiescent stem cells into the cell cycle is a key step in initiating the process of tissue repair. We recently reported that quiescent stem cells can transition into GAlert, a cellular state in which they have an increased functional ability to activate and participate in tissue repair. However, the precise molecular signals that induce GAlert in stem cells have remained elusive. Here, we show that the injury-induced regulation of hepatocyte growth factor (HGF) proteolytic processing via the systemic protease, hepatocyte growth factor activator (HGFA), stimulates GAlert in skeletal muscle stem cells (MuSCs) and fibro-adipogenic progenitors (FAPs). We demonstrate that administering active HGFA to animals is sufficient to induce GAlert in stem cells throughout the body and to significantly accelerate the processes of stem cell activation and tissue repair. Our data suggest that factors that induce GAlert will have broad therapeutic applications for regenerative medicine and wound healing.

Restoring Conscious Arousal During Focal Limbic Seizures with Deep Brain Stimulation.

Impaired consciousness occurs suddenly and unpredictably in people with epilepsy, markedly worsening quality of life and increasing risk of mortality. Focal seizures with impaired consciousness are the most common form of epilepsy and are refractory to all current medical and surgical therapies in about one-sixth of cases. Restoring consciousness during and following seizures would be potentially transformative for these individuals. Here, we investigate deep brain stimulation to improve level of conscious arousal in a rat model of focal limbic seizures. We found that dual-site stimulation of the central lateral nucleus of the intralaminar thalamus (CL) and the pontine nucleus oralis (PnO) bilaterally during focal limbic seizures restored normal-appearing cortical electrophysiology and markedly improved behavioral arousal. In contrast, single-site bilateral stimulation of CL or PnO alone was insufficient to achieve the same result. These findings support the "network inhibition hypothesis" that focal limbic seizures impair consciousness through widespread inhibition of subcortical arousal. Driving subcortical arousal function would be a novel therapeutic approach to some forms of refractory epilepsy and may be compatible with devices already in use for responsive neurostimulation. Multisite deep brain stimulation of subcortical arousal structures may benefit not only patients with epilepsy but also those with other disorders of consciousness.

Optogenetic stimulation of cholinergic brainstem neurons during focal limbic seizures: Effects on cortical physiology.

Focal temporal lobe seizures often cause impaired cortical function and loss of consciousness. Recent work suggests that the mechanism for depressed cortical function during focal seizures may depend on decreased subcortical cholinergic arousal, which leads to a sleep-like state of cortical slow-wave activity. To test this hypothesis, we sought to directly activate subcortical cholinergic neurons during focal limbic seizures to determine the effects on cortical function. Here we used an optogenetic approach to selectively stimulate cholinergic brainstem neurons in the pedunculopontine tegmental nucleus during focal limbic seizures induced in a lightly anesthetized rat model. We found an increase in cortical gamma activity and a decrease in delta activity in response to cholinergic stimulation. These findings support the mechanistic role of reduced subcortical cholinergic arousal in causing cortical dysfunction during seizures. Through further work, electrical or optogenetic stimulation of subcortical arousal networks may ultimately lead to new treatments aimed at preventing cortical dysfunction during seizures.