BMJ Open Science最新文献

Preclinical research is a vital step in the drug discovery pipeline and more generally in helping to better understand human disease aetiology and its management. Systematic reviews (SRs) can be powerful in summarising and appraising this evidence concerning a specific research question, to highlight areas of improvements, areas for further research and areas where evidence may be sufficient to take forward to other research domains, for instance clinical trial. Guidance and tools for preclinical research synthesis remain limited despite their clear utility. We aimed to create an online end-to-end platform primarily for conducting SRs of preclinical studies, that was flexible enough to support a wide variety of experimental designs, was adaptable to different research questions, would allow users to adopt emerging automated tools and support them during their review process using best practice. In this article, we introduce the Systematic Review Facility (https://syrf.org.uk), which was launched in 2016 and designed to support primarily preclinical SRs from small independent projects to large, crowdsourced projects. We discuss the architecture of the app and its features, including the opportunity to collaborate easily, to efficiently manage projects, to screen and annotate studies for important features (metadata), to extract outcome data into a secure database, and tailor these steps to each project. We introduce how we are working to leverage the use of automation tools and allow the integration of these services to accelerate and automate steps in the systematic review workflow.

Objective: Studies in rodents associated the deficits of adult hippocampal neurogenesis with behavioural anomalies which may be reversed by antidepressant treatments. A previous systematic review (SR) and meta-analysis (MA) indicated a hierarchy within the proneurogenic effects of different antidepressants in naive rodents. The present review aims to evaluate a more comprehensive sample of studies investigating the links between the effects of different antidepressants and adult hippocampal neurogenesis.

Search strategy screening annotation data management: Protocols were planned following Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. Searches in Embase, Medline, Scopus and Web of Science followed by screening with inclusion/exclusion criteria will provide relevant publications. First SR will summarise the effects of antidepressants on adult hippocampal neurogenesis on different laboratory rodents. Second SR will summarise the correlations between neurogenic and behavioural effects of antidepressants while the third will focus on cause-effect relationships between them. If feasible, data will be analysed by pairwise or network random-effect or multivariate MA to determine the direction, magnitude, significance and heterogeneity (I²) of the estimated effect sizes on global or subgroup levels. Funnel plotting, Egger regression, 'trim and fill' will be used to estimate the risk of publication bias. Quality assessment of the included publications will be performed by applying adapted CAMARADES, Syrcles' risk of bias or CINeMA tools.

Reporting: Find a preliminary version of this protocol at the Open Science Framework (https://osf.io/gmsvd/). Data extraction has already started. Results shall be published in a peer-reviewed journal. Due to the continuous production in the field, the implementation of a 'living SR' is intended.

Objective: Thigmotaxis is an innate predator avoidance behaviour of rodents and is enhanced when animals are under stress. It is characterised by the preference of a rodent to seek shelter, rather than expose itself to the aversive open area. The behaviour has been proposed to be a measurable construct that can address the impact of pain on rodent behaviour. This systematic review will assess whether thigmotaxis can be influenced by experimental persistent pain and attenuated by pharmacological interventions in rodents.

Search strategy: We will conduct search on three electronic databases to identify studies in which thigmotaxis was used as an outcome measure contextualised to a rodent model associated with persistent pain. All studies published until the date of the search will be considered.

Screening and annotation: Two independent reviewers will screen studies based on the order of (1) titles and abstracts, and (2) full texts.

Data management and reporting: For meta-analysis, we will extract thigmotactic behavioural data and calculate effect sizes. Effect sizes will be combined using a random-effects model. We will assess heterogeneity and identify sources of heterogeneity. A risk-of-bias assessment will be conducted to evaluate study quality. Publication bias will be assessed using funnel plots, Egger's regression and trim-and-fill analysis. We will also extract stimulus-evoked limb withdrawal data to assess its correlation with thigmotaxis in the same animals. The evidence obtained will provide a comprehensive understanding of the strengths and limitations of using thigmotactic outcome measure in animal pain research so that future experimental designs can be optimised. We will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines and disseminate the review findings through publication and conference presentation.

Within preclinical research, attention has focused on experimental design and how current practices can lead to poor reproducibility. There are numerous decision points when designing experiments. Ethically, when working with animals we need to conduct a harm-benefit analysis to ensure the animal use is justified for the scientific gain. Experiments should be robust, not use more or fewer animals than necessary, and truly add to the knowledge base of science. Using case studies to explore these decision points, we consider how individual experiments can be designed in several different ways. We use the Experimental Design Assistant (EDA) graphical summary of each experiment to visualise the design differences and then consider the strengths and weaknesses of each design. Through this format, we explore key and topical experimental design issues such as pseudo-replication, blocking, covariates, sex bias, inference space, standardisation fallacy and factorial designs. There are numerous articles discussing these critical issues in the literature, but here we bring together these topics and explore them using real-world examples allowing the implications of the choice of design to be considered. Fundamentally, there is no perfect experiment; choices must be made which will have an impact on the conclusions that can be drawn. We need to understand the limitations of an experiment's design and when we report the experiments, we need to share the caveats that inherently exist.

Introduction: Multicentre preclinical randomised controlled trials (pRCT) are emerging as a necessary step to confirm efficacy and improve translation into the clinic. The aim of this project is to perform two multicentre pRCTs (one in rats and one in mice) to investigate the efficacy of remote ischaemic conditioning (RIC) in an experimental model of severe ischaemic stroke.

Methods and analysis: Seven research laboratories within the Italian Stroke Organization (ISO) Basic Science network will participate in the study. Transient endovascular occlusion of the proximal right middle cerebral artery will be performed in two species (rats and mice) and in both sexes. Animals will be randomised to receive RIC by transient surgical occlusion of the right femoral artery, or sham surgery, after reperfusion. Blinded outcome assessment will be performed for dichotomised functional neuroscore (primary endpoint) and infarct volume (secondary endpoint) at 48 hours. A sample size of 80 animals per species will yield 82% power to detect a significant difference of 30% in the primary outcome in both pRCTs. Analyses will be performed in a blind status and according to an intention-to-treat paradigm. The results of this study will provide robust, translationally oriented, high-quality evidence on the efficacy of RIC in multiple species of rodents with large ischaemic stroke.

Ethics and dissemination: This is approved by the Animal Welfare Regulatory Body of the University of Milano Bicocca, under project license from the Italian Ministry of Health. Trial results will be subject to publication according to the definition of the outcome presented in this protocol.

Trial registration number: PCTE0000177.

Introduction and objective: The Western diet that comprises high levels of long-chain saturated fats and sugar is associated not only with metabolic disorders such as obesity and type 2 diabetes but also has been recently linked to brain changes and cognitive dysfunction. However, in animal studies, reported effects are variable, and the mechanisms underlying these effects are unclear. In the proposed review, we aim to summarise the diverse evidence of the effects of so-called 'high-fat' and ketogenic diets on behavioural measures of cognition in postweaning mice and rats, relative to animals on standard diets and to determine potential underlying mechanisms of high-fat diet-induced effects.

Search strategy: A comprehensive search strategy was designed to retrieve studies reporting use of a high-fat or ketogenic diet in postweaning mice and rats that included cognitive assessments. Three databases (Medline, SCOPUS and Web of Science) were searched and 4487 unique references were retrieved.

Screening and annotation: Studies were screened for inclusion by two independent reviewers, with 330 studies retained for analysis. Characteristics of disease model choice, experimental design, intervention use and outcome assessment are to be extracted using the Systematic Review Facility (http://syrf.org.uk/) tool. Studies will be assessed for study quality and risk of bias and confidence of mechanistic involvement.

Data management and reporting: For cognitive outcomes, effect sizes will be calculated using normalised mean difference and summarised using a random effects model. The contribution of potential sources of heterogeneity to the observed effects of diet on cognition will be assessed using multivariable meta-regression, with partitioning of heterogeneity as a sensitivity analysis. A preliminary version of this protocol was published on 9 April 2019 on the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies website (http://www.dcn.ed.ac.uk/camarades/research.html%23protocols).

Ethics and dissemination: No ethical approval is required as there are no subjects in the proposed study.

Background: Cancer remains a global threat resulting in significant morbidity and mortality despite advances in therapeutic interventions, suggesting urgency for identification of anticancer agents. Crocodiles thrive in polluted habitat, feed on germ-infested meat, are exposed to carcinogenic heavy metals, are the very few species to survive the catastrophic Cretaceous-Paleogene extinction event, yet have a prolonged lifespan and rarely been reported to develop cancer. Therefore, we hypothesised that animals living in polluted environments such as crocodiles possess anticancer molecules/mechanisms.

Methods: Crocodylus porosus was procured, blood collected, dissected and lysates prepared from internal organs. Organ lysates and sera were tested for growth inhibition, cytotoxic effects and cell survival against HeLa, PC3 and MCF7 cells and subjected to liquid chromatography mass spectrometry. RNA transcriptome analysis and differential gene analysis were performed using Galaxy Bioinformatics.

Results: Sera exhibited potent growth inhibition and cytotoxic effects against cancer cells. 80 molecules were detected from C. porosus and 19 molecules were putatively identified. Additionally, more than 100 potential anticancer peptides were identified from sera using bioinformatics based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition. Following transcriptome analysis, 14 genes in treated HeLa cells, 51 genes in treated MCF7 cells and 2 genes in treated PC3 cells, were found to be expressed, compared with untreated controls.

Conclusion: Animals residing in polluted milieus are an unexploited source for prospective pharmaceutical drugs, and could lead to identification of novel antitumour compound(s) and/or further understanding of the mechanisms of cancer resistance.

Objectives: We evaluated animal-based biomedical 'breakthroughs' reported in the UK national press in 1995 (25 years prior to the conclusion of this study). Based on evidence of overspeculative reporting of biomedical research in other areas (eg, press releases and scientific papers), we specifically examined animal research in the media, asking, 'In a given year, what proportion of animal research "breakthroughs"' published in the UK national press had translated, more than 20 years later, to approved interventions?'

Methods: We searched the Nexis media database (LexisNexis.com) for animal-based biomedical reports in the UK national press. The only restrictions were that the intervention should be specific, such as a named drug, gene, biomedical pathway, to facilitate follow-up, and that there should be claims of some clinical promise.

Main outcome measures: Were any interventions approved for human use? If so, when and by which agency? If not, why, and how far did development proceed? Were any other, directly related interventions approved? Did any of the reports overstate human relevance?

Results: Overspeculation and exaggeration of human relevance was evident in all the articles examined. Of 27 unique published 'breakthroughs', only one had clearly resulted in human benefit. Twenty were classified as failures, three were inconclusive and three were partially successful.

Conclusions: The results of animal-based preclinical research studies are commonly overstated in media reports, to prematurely imply often-imminent 'breakthroughs' relevant to human medicine.