"Untangling" Alzheimer's disease and epilepsy.
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ABSTRACT:
SUBMITTER: Scharfman HE
PROVIDER: S-EPMC3482723 | biostudies-other | 2012 Sep
REPOSITORIES: biostudies-other
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Project description:Alzheimer's disease (AD) is a genetically heterogeneous neurodegenerative disorder caused by fully penetrant single gene mutations in a minority of cases, while the majority of cases are sporadic or show modest familial clustering. These cases are of late onset and likely result from the interaction of many genes and the environment. More than 30 loci have been implicated in AD by a combination of linkage, genome-wide association, and whole genome/exome sequencing. We have learned from these studies that perturbations in endolysosomal, lipid metabolism, and immune response pathways substantially contribute to sporadic AD pathogenesis. We review here current knowledge about functions of AD susceptibility genes, highlighting cells of the myeloid lineage as drivers of at least part of the genetic component in late-onset AD. Although targeted resequencing utilized for the identification of causal variants has discovered coding mutations in some AD-associated genes, a lot of risk variants lie in noncoding regions. Here we discuss the use of functional genomics approaches that integrate transcriptomic, epigenetic, and endophenotype traits with systems biology to annotate genetic variants, and to facilitate discovery of AD risk genes. Further validation in cell culture and mouse models will be necessary to establish causality for these genes. This knowledge will allow mechanism-based design of novel therapeutic interventions in AD and promises coherent implementation of treatment in a personalized manner.
| S-EPMC5699970 | biostudies-literature
Project description:This SuperSeries is composed of the following subset Series: GSE6771: Temporal Cortex Control (mesial temporal lobe epilepsy control) GSE6773: Temporal neocortex mesial temporal lobe epilepsy GSE6774: Temporal Cortex Control (Alzheimer's disease control) GSE6775: Temporal Cortex Alzheimer's Disease GSE6777: Cerebellum Alzheimer's Disease GSE6778: Cerebellum Control (Alzheimer's disease control) Keywords: SuperSeries Refer to individual Series
2007-01-23 | E-GEOD-6834 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below.
2007-01-23 | GSE6834 | GEO
Project description:BACKGROUND:Any type of seizure can be observed in Alzheimer's disease (AD). Antiepileptic drugs seem to prevent the recurrence of epileptic seizures in most people with AD. There are pharmacological and non-pharmacological treatments for epilepsy in people with AD. There are no current systematic reviews to evaluate the efficacy and tolerability of these treatments; this review aims to review those different modalities. This is an updated version of the original Cochrane Review published in Issue 11, 2016. OBJECTIVES:To assess the efficacy and tolerability of pharmacological or non-pharmacological interventions for the treatment of epilepsy in people with AD (including sporadic AD and dominantly inherited AD). SEARCH METHODS:For the latest update, on 10 July 2018 we searched the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group's Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid 1946- ), ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP). In an effort to identify further published, unpublished and ongoing trials, we searched ongoing trials registers, reference lists and relevant conference proceedings, and contacted authors and pharmaceutical companies. SELECTION CRITERIA:We included randomized and quasi-randomized controlled trials investigating treatment for epilepsy in people with AD, with the outcomes of proportion of participants with seizure freedom or proportion of participants experiencing adverse events. DATA COLLECTION AND ANALYSIS:Two review authors independently screened the titles and abstracts of identified records, selected studies for inclusion, extracted data, cross-checked the data for accuracy and assessed the methodological quality. We performed no meta-analyses due to the limited available data. MAIN RESULTS:We included one randomized controlled trial on pharmacological interventions with 95 participants. No studies were found for non-pharmacological interventions. Concerning the proportion of participants with seizure freedom, no significant differences were found for the comparisons of levetiracetam (LEV) versus lamotrigine (LTG) (risk ratio (RR) 1.20, 95% confidence interval (CI) 0.53 to 2.71), LEV versus phenobarbital (PB) (RR 1.01, 95% CI 0.47 to 2.19), or LTG versus PB (RR 0.84, 95% CI 0.35 to 2.02). It seemed that LEV could improve cognition and LTG could relieve depression, while PB and LTG could worsen cognition, and LEV and PB could worsen mood. Unclear risk of bias was found in allocation, blinding and selective reporting. We judged the quality of the evidence to be very low. AUTHORS' CONCLUSIONS:This review does not provide sufficient evidence to support LEV, PB or LTG for the treatment of epilepsy in people with AD. Regarding efficacy and tolerability, no significant differences were found between LEV, PB and LTG. Large randomized controlled trials with a double-blind, parallel-group design are required to determine the efficacy and tolerability of treatment for epilepsy in people with AD.
| S-EPMC6516988 | biostudies-literature
Project description:Alzheimer's disease (AD) is the most common form of dementia present in older adults; its etiology involves genetic and environmental factors. In recent years, epidemiological studies have shown a correlation between AD and chronic epilepsy since a considerable number of patients with AD may present seizures later on. Although the pathophysiology of seizures in AD is not completely understood, it could represent the result of several molecular mechanisms linked to amyloid beta-peptide (A?) accumulation and the hyperphosphorylation of tau protein, which may induce an imbalance in the release and recapture of excitatory and inhibitory neurotransmitters, structural alterations of the neuronal cytoskeleton, synaptic loss, and neuroinflammation. These changes could favor the recurrent development of hypersynchronous discharges and epileptogenesis, which, in a chronic state, favor the neurodegenerative process and influence the cognitive decline observed in AD. Supporting this correlation, histopathological studies in the brain tissue of temporal lobe epilepsy (TLE) patients have revealed the presence of A? deposits and the accumulation of tau protein in the neurofibrillary tangles (NFTs), accompanied by an increase of glycogen synthase kinase-3 beta (GSK3?) activity that may lead to an imminent alteration in posttranslational modifications of some microtubule-associated proteins (MAPs), mainly tau. The present review is focused on understanding the pathological aspects of GSK3? and tau in the development of TLE and AD.
| S-EPMC7089874 | biostudies-literature
Project description:BackgroundNeuroinflammation is an innate immunological response of the central nervous system that may be induced by a brain insult and chronic neurodegenerative conditions. Recent research has shown that neuroinflammation may contribute to the initiation of Alzheimer's disease (AD) pathogenesis and associated epileptogenesis.ObjectiveThis systematic review aimed to investigate the available literature on the shared molecular mechanisms of neuroinflammation in AD and epilepsy.MethodsThe search included in this systematic review was obtained from 5 established databases. A total of 2,760 articles were screened according to inclusion criteria. Articles related to the modulation of the inflammatory biomarkers commonly associated with the progression of AD and epilepsy in all populations were included in this review.ResultsOnly 7 articles met these criteria and were chosen for further analysis. Selected studies include both in vitro and in vivo research conducted on rodents. Several neuroinflammatory biomarkers were reported to be involved in the cross-talk between AD and epilepsy.ConclusionNeuroinflammation was directly associated with the advancement of AD and epilepsy in populations compared to those with either AD or epilepsy. However, more studies focusing on common inflammatory biomarkers are required to develop standardized monitoring guidelines to prevent the manifestation of epilepsy and delay the progression of AD in patients.
| S-EPMC10473147 | biostudies-literature
Project description:It is currently unclear how amyloid-β and tau deposition are linked to changes in synaptic function and axonal structure over the course of Alzheimer's disease. Here, we assessed these relationships by measuring presynaptic (synaptosomal-associated protein 25, SNAP25; growth-associated protein 43, GAP43), postsynaptic (neurogranin, NRGN) and axonal (neurofilament light chain) markers in the CSF of individuals with varying levels of amyloid-β and tau pathology based on 18F-flutemetamol PET and 18F-flortaucipir PET. In addition, we explored the relationships between synaptic and axonal markers with cognition as well as functional and anatomical brain connectivity markers derived from resting-state functional MRI and diffusion tensor imaging. We found that the presynaptic and postsynaptic markers SNAP25, GAP43 and NRGN are elevated in early Alzheimer's disease i.e. in amyloid-β-positive individuals without evidence of tau pathology. These markers were associated with greater amyloid-β pathology, worse memory and functional changes in the default mode network. In contrast, neurofilament light chain was abnormal in later disease stages, i.e. in individuals with both amyloid-β and tau pathology, and correlated with more tau and worse global cognition. Altogether, these findings support the hypothesis that amyloid-β and tau might have differential downstream effects on synaptic and axonal function in a stage-dependent manner, with amyloid-related synaptic changes occurring first, followed by tau-related axonal degeneration.
| S-EPMC8210638 | biostudies-literature
Project description:Alzheimer's disease (AD) and epilepsy are neurological disorders that affect a large cohort of people worldwide. Although both of the two diseases could be influenced by genetic factors, the shared genetic mechanism underlying the pathogenesis of them is still unclear. In this study, we aimed to identify the shared genetic networks and corresponding hub genes for AD and epilepsy. Firstly, the gene coexpression modules (GCMs) were constructed by weighted gene coexpression network analysis (WGCNA), and 16 GCMs were identified. Through further integration of GCMs, genome-wide association studies (GWASs), and expression quantitative trait loci (eQTLs), 4 shared GCMs of AD and epilepsy were identified. Functional enrichment analysis was performed to analyze the shared biological processes of these GCMs and explore the functional overlaps between these two diseases. The results showed that the genes in shared GCMs were significantly enriched in nervous system-related pathways, such as Alzheimer's disease and neuroactive ligand-receptor interaction pathways. Furthermore, the hub genes of AD- and epilepsy-associated GCMs were captured by weighted key driver analysis (wKDA), including TRPC1, C2ORF40, NR3C1, KIAA0368, MMT00043109, STEAP1, MSX1, KL, and CLIC6. The shared GCMs and hub genes might provide novel therapeutic targets for AD and epilepsy.
| S-EPMC8538392 | biostudies-literature
Project description:Dravet syndrome (also known as Severe Myoclonic Epilepsy of Infancy) is a rare genetic epilepsy syndrome commonly associated with loss-of-function mutations in SCN1A, the gene encoding the α subunit of the voltage-gated sodium channel NaV1.1, resulting in haploinsufficiency. Like other voltage-gated sodium channels, NaV1.1 function contributes to the rising phase of the neuronal action potential; thus, the observation that loss-of-function mutations in this channel gene are associated with seizures has created a paradox for the field. Major work has been done to untangle this paradox during the past decade, resulting in the development of two distinct hypotheses to explain seizures in Dravet syndrome. Here, we review the history of these two hypotheses and speculate as to what the history of Dravet syndrome research might tell us about its future.
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