scholarly journals Differential expression of microRNAs in Alzheimer's disease brain, blood and cerebrospinal fluid: a systematic review and meta-analysis

2018 ◽  
Author(s):  
Petros Takousis ◽  
Angélique Sadlon ◽  
Jessica Schulz ◽  
Inken Wohlers ◽  
Valerija Dobricic ◽  
...  

INTRODUCTION: Several microRNAs (miRNAs) have been implicated in Alzheimer's disease (AD) pathogenesis but the evidence from individual case control studies remains inconclusive. METHODS: A systematic literature review was performed, followed by standardised multi-stage data extraction, quality control, and meta-analyses on eligible data for brain, blood, and cerebrospinal fluid (CSF) specimens. Results were compared with miRNAs reported in the abstracts of eligible studies or recent qualitative reviews to assess novelty. RESULTS: Data from 147 independent datasets across 107 publications were quantitatively assessed in 461 meta-analyses. Twenty-five, five, and 32 miRNAs showed study-wide significant differential expression (α<1.08x10-4) in brain, CSF, and blood-derived specimens, respectively, with 5 miRNAs showing differential expression in both brain and blood. Of these 57 miRNAs, 13 had not been reported in the abstracts of previous original or review articles. DISCUSSION: Our systematic assessment of differential miRNA expression is the first of its kind in AD and highlights miRNAs of relevance.

2021 ◽  
pp. 219256822110668
Author(s):  
Kenney K. L. Lau ◽  
Karlen K. P. Law ◽  
Kenny Y. H. Kwan ◽  
Jason P. Y. Cheung ◽  
Kenneth M. C. Cheung ◽  
...  

Study Design Systematic review and meta-analysis Objectives The present review aimed to summarize the evidence regarding differences in proprioception between children with and without adolescent idiopathic scoliosis (AIS). Methods Seven electronic databases were searched from their inception to April 10, 2021. Articles were included if they involved: (1) AIS patients aged between 10 and 18 years, (2) measurements of proprioceptive abilities, and (3) comparisons with non-AIS controls. Animal studies, case reports, commentaries, conference proceedings, research protocols, and reviews were excluded. Two reviewers independently conducted literature screening, data extraction, risks of bias assessments, and quality of evidence evaluations. Relevant information was pooled for meta-analyses. Results From 432 identified citations, 11 case-control studies comprising 1121 participants were included. The meta-analyses showed that AIS participants displayed proprioceptive deficits as compared to non-AIS controls. Moderate evidence supported that AIS participants showed significantly larger repositioning errors than healthy controls (pooled mean difference = 1.27 degrees, P < .01). Low evidence substantiated that AIS participants had significantly greater motion detection threshold (pooled mean difference = 1.60 degrees, P < .01) and abnormal somatosensory evoked potentials (pooled mean difference = .36 milliseconds, P = .01) than non-AIS counterparts. Conclusions Consistent findings revealed that proprioceptive deficits occurred in AIS patients. Further investigations on the causal relationship between AIS and proprioception, and the identification of the subgroup of AIS patients with proprioceptive deficit are needed.


Author(s):  
Lars-Gunnar Gunnarsson ◽  
Lennart Bodin

Objectives: To carry out an integrated and stratified meta-analysis on occupational exposure to electromagnetic fields (EMFs), metals and pesticides and its effects on amyotrophic lateral sclerosis (ALS) and Parkinson’s and Alzheimer’s disease, and investigate the possibility of publication bias. Methods: In the current study, we updated our recently published meta-analyses on occupational exposures in relation to ALS, Alzheimer’s and Parkinson’s disease. Based on 66 original publications of good scientific epidemiological standard, according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) guidelines, we analysed subgroups by carrying out stratified meta-analyses on publication year, statistical precision of the relative risk (RR) estimates, inspection of the funnel plots and test of bias. Results: Based on 19 studies the weighted RR for occupational exposure to EMFs was 1.26 (95% confidence interval (CI) 1.07–1.50) for ALS, 1.33 (95% CI 1.07–1.64) for Alzheimer’s disease and 1.02 (95% CI 0.83–1.26) for Parkinson’s disease. Thirty-one studies concerned occupational exposure to pesticides and the weighted RR was 1.35 (95% CI 1.02–1.79) for ALS, 1.50 (95% CI 0.98–2.29) for Alzheimer’s disease and 1.66 (95% CI 1.42–1.94) for Parkinson’s disease. Finally, 14 studies concerned occupational exposure to metals and only exposure to lead (five studies) involved an elevated risk for ALS or Parkinson’s disease and the weighted RR was 1.57 (95% CI 1.11–2.20). The weighted RR for all the non-lead exposures was 0.97 (95% CI 0.88–1.06). Conclusions: Exposure to pesticides increased the risk of getting the mentioned neurodegenerative diseases by at least 50%. Exposure to lead was only studied for ALS and Parkinson’s disease and involved 50% increased risk. Occupational exposure to EMFs seemed to involve some 10% increase in risk for ALS and Alzheimer’s disease only.


2019 ◽  
Vol 15 (7) ◽  
pp. P1616
Author(s):  
Lianne M. Reus ◽  
Sven Stringer ◽  
Danielle Posthuma ◽  
Charlotte E. Teunissen ◽  
Philip Scheltens ◽  
...  

2019 ◽  
Author(s):  
Vandana Rai

AbstractMethylenetetrahydrofolate reductase (MTHFR) is a crucial enzyme involved in homocysteine/methionone metabolism. It catalyzes the conversion of 5,10methlenetetrahydrofolate in to 5methyltetrahydrofolate. A number of studies have examined the association of MTHFR A1298C polymorphism as risk factor for Alzheimer’s disease (AD), but the results were contradictory. To clarify the influence of MTHFR A1298C polymorphism on Alzheimer’s disease (AD), a meta-analysis of ten case-control studies was carried out. Four electronic databases were searched up to August, 2019 for suitable articles. The pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to evaluate the association. All statistical analyses were performed by MetaAnalyst program.The results of meta-analysis suggested that except allele contrast model, A1298C polymorphism is not risk for Alzheimer’s disease using overall comparisons in three genetic models (C vs. A: OR= 1.26, 95%CI= 0.912-1.76, p= 0.04; CC+AC vs. AA: OR= 1.43; 95%CI= 0.85-2.44; p=0.05; CC vs. AA: OR= 1.16, 95%CI= .88-1.55, p= 0.51; AC vs. AA: 1.55; 95%CI= 0.81-2.93,p=0.07). Publication bias was absent in all five genetic models. In conclusion, results of present meta-analysis showed no significant association between MTHFR A1298C polymorphism and AD risk.


2019 ◽  
Vol 1 ◽  
pp. 15 ◽  
Author(s):  
Nicla Manzari ◽  
Karen Matvienko-Sikar ◽  
Franco Baldoni ◽  
Gerard W. O'Keeffe ◽  
Ali S. Khashan

Background: Prenatal maternal stress (PNMS) is defined as the experience of significant levels of prenatal stress, depression or anxiety during pregnancy. PNMS has been associated with increased risk of autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD) in exposed offspring. However, these findings are inconsistent and other studies found no association, meaning a clear consensus on the impact of PNMS on ASD and ADHD risk is required. The purpose of this systematic review and meta-analysis is to summarize and critically review the existing literature on the effects of PNMS on ASD and ADHD risk. Methods: Electronic databases (PubMed, PsycINFO, Web of Science, Scopus and EMBASE) will be searched for articles following a detailed search strategy. We will include cohort and case-control studies that assessed maternal exposure to psychological and/or environmental stress and had ASD or ADHD as an outcome. Two reviewers will independently screen the titles, abstracts and full articles to identify eligible studies. We will use a standardised data extraction form for extracting data and a bias classification tool for assessing study quality. This systematic review will be reported according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). The generic inverse variance method will be used if possible to perform meta-analyses. Ethics and dissemination: Ethical approval is not required for this study because it will not involve the conduct or inclusion of any experimental or personal data that would require informed consent.  The systematic review will be disseminated in peer-reviewed journals. PROSPERO registration number: CRD42018084222.


2021 ◽  
Vol 79 (1) ◽  
pp. 177-195
Author(s):  
Ivan Koychev ◽  
Katrin Jansen ◽  
Alina Dette ◽  
Liu Shi ◽  
Heinz Holling

Background: The Amyloid Tau Neurodegeneration (ATN) framework was proposed to define the biological state underpinning Alzheimer’s disease (AD). Blood-based biomarkers offer a scalable alternative to the costly and invasive currently available biomarkers. Objective: In this meta-analysis we sought to assess the diagnostic performance of plasma amyloid (Aβ40, Aβ42, Aβ42/40 ratio), tangle (p-tau181), and neurodegeneration (total tau [t-tau], neurofilament light [NfL]) biomarkers. Methods: Electronic databases were screened for studies reporting biomarker concentrations for AD and control cohorts. Biomarker performance was examined by random-effect meta-analyses based on the ratio between biomarker concentrations in patients and controls. Results: 83 studies published between 1996 and 2020 were included in the analyses. Aβ42/40 ratio as well as Aβ42 discriminated AD patients from controls when using novel platforms such as immunomagnetic reduction (IMR). We found significant differences in ptau-181 concentration for studies based on single molecule array (Simoa), but not for studies based on IMR or ELISA. T-tau was significantly different between AD patients and control in IMR and Simoa but not in ELISA-based studies. In contrast, NfL differentiated between groups across platforms. Exosome studies showed strong separation between patients and controls for Aβ42, t-tau, and p-tau181. Conclusion: Currently available assays for sampling plasma ATN biomarkers appear to differentiate between AD patients and controls. Novel assay methodologies have given the field a significant boost for testing these biomarkers, such as IMR for Aβ, Simoa for p-tau181. Enriching samples through extracellular vesicles shows promise but requires further validation.


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