Extrapolating from animals to humans

Analysis of animal-to-human translation shows that only 5% of animal-tested therapeutic interventions obtain regulatory approval for human applications

There is an ongoing debate about the value of animal experiments to inform medical practice, yet there are limited data on how well therapies developed in animal studies translate to humans. We aimed to assess 2 measures of translation across various biomedical fields: (1) The proportion of therapies which transition from animal studies to human application, including involved timeframes; and (2) the consistency between animal and human study results. Thus, we conducted an umbrella review, including English systematic reviews that evaluated the translation of therapies from animals to humans. Medline, Embase, and Web of Science Core Collection were searched from inception until August 1, 2023. We assessed the proportion of therapeutic interventions advancing to any human study, a randomized controlled trial (RCT), and regulatory approval. We meta-analyzed the concordance between animal and human studies. The risk of bias was probed using a 10-item checklist for systematic reviews. We included 122 articles, describing 54 distinct human diseases and 367 therapeutic interventions. Neurological diseases were the focus of 32% of reviews. The overall proportion of therapies progressing from animal studies was 50% to human studies, 40% to RCTs, and 5% to regulatory approval. Notably, our meta-analysis showed an 86% concordance between positive results in animal and clinical studies. The median transition times from animal studies were 5, 7, and 10 years to reach any human study, an RCT, and regulatory approval, respectively. We conclude that, contrary to widespread assertions, the rate of successful animal-to-human translation may be higher than previously reported. Nonetheless, the low rate of final approval indicates potential deficiencies in the design of both animal studies and early clinical trials. To ameliorate the efficacy of translating therapies from bench to bedside, we advocate for enhanced study design robustness and the reinforcement of generalizability.

Value of preclinical systematic reviews and meta-analyses in pediatric research

Similar to systematic reviews (SRs) in clinical fields, preclinical SRs address a specific research area, furnishing information on current knowledge, possible gaps, and potential methodological flaws of study design, conduct, and report. One of the main goals of preclinical SRs is to identify aspiring treatment strategies and evaluate if currently available data is solid enough to translate to clinical trials or highlight the gaps, thus justifying the need for new studies. It is imperative to rigorously follow the methodological standards that are widely available. These include registration of the protocol and adherence to guidelines for assessing the risk of bias, study quality, and certainty of evidence. A special consideration should be made for pediatric SRs, clinical and preclinical, due to the unique characteristics of this age group. These include rationale for intervention and comparison of primary and secondary outcomes. Outcomes measured should acknowledge age-related physiological changes and maturational processes of different organ systems. It is crucial to choose the age of the animals appropriately and its possible correspondence for specific pediatric age groups. The findings of well-conducted SRs of preclinical studies have the potential to provide a reliable evidence synthesis to guide the design of future preclinical and clinical studies. IMPACT: This narrative review highlights the importance of rigorous design, conduct and reporting of preclinical primary studies and systematic reviews. A special consideration should be made for pediatric systematic reviews of preclinical studies, due to the unique characteristics of this age group.

Twelve years after the ARRIVE guidelines: Animal research has not yet arrived at high standards

The reproducibility crisis across animal studies jeopardizes the credibility of the main findings derived from animal research, even though these findings are critical for informing human studies. To clarify and improve transparency among animal studies, the ARRIVE reporting guidelines were first announced in 2010 and upgraded to version 2.0 in 2020. However, compliance with and awareness of those reporting guidelines has remained suboptimal. Journal editors should encourage the authors to adhere to those guidelines. Authors, editors, referees, and reviewers should be aware of the ARRIVE guideline 2.0 when assessing and evaluating the methodology and findings of animal studies. However, we should also question whether reporting guidelines alone can change a research culture and improve the reproducibility of animal investigations. Reported research may not reflect actual research. Large segments of animal research efforts are wasted because of poor design choices and because of non-publication rather than suboptimal reporting. Better training of the scientific workforce, interventions at improving animal research at the design stage, registration practices, and alignment of the reward system with the publication of rigorous animal research may achieve more than reporting guidelines alone.

A scoping review on efficacy and safety of medicinal plants used for the treatment of diarrhea in sub-Saharan Africa

BACKGROUND

In sub-Saharan Africa (SSA), significant morbidity and mortality have been linked to diarrhea, which is frequently caused by microorganisms. A rise in antimicrobial-resistant pathogens has reignited the search for alternative therapies. This scoping review aims to map the literature on medicinal plants in relation to their anti-diarrheal potential from SSA.

METHODS

Studies published from 1990 until April 2022 on medicinal plants used for the treatment of diarrhea from each country in SSA were searched on Scopus, Web of Science, Science Direct and PubMed. The selection of articles was based on the availability of data on the in vitro and/or in vivo, ethnobotanical, and cross-sectional studies on the efficacy of medicinal plants against diarrhea. A total of 67 articles (ethnobotanical (n = 40); in vitro (n = 11), in vivo (n = 7), cross-sectional (n = 3), in vitro and in vivo (n = 2) and ethnobotanical and in vitro (n = 2), were considered for the descriptive analysis, which addressed study characteristics, herbal intervention information, phytochemistry, outcome measures, and toxicity findings.

RESULTS

A total of 587 different plant species (from 123 families) used for diarrhea treatment were identified. Most studies were conducted on plants from the Fabaceae family. The plants with the strongest antimicrobial activity were Indigofera daleoides and Punica granatum. Chromatographic methods were used to isolate six pure compounds from ethyl acetate extract of Hydnora johannis, and spectroscopic methods were used to determine their structures. The majority of anti-diarrheal plants were from South Africa (23.9%), Ethiopia (16.4%), and Uganda (9%). This study highlights the value of traditional remedies in treating common human diseases such as diarrhea in SSA.

CONCLUSION

Baseline knowledge gaps were identified in various parts of SSA. It is therefore recommended that future ethnobotanical studies document the knowledge held by other countries in SSA that have so far received less attention. Additionally, we recommend that future studies conduct phytochemical investigations, particularly on the widely used medicinal plants for the treatment of diarrheal illnesses, which can serve as a foundation for future research into the development of contemporary drugs.

Are Supra-Physiological Plant-Based Antioxidants Ready for the Clinic? A Scoping Review of Hormetic Influences Driving Positive Clinical Outcomes

Background: A pro-inflammatory metabolic state is key to the chronic disease epidemic. Clinicians' ability to use nutrients to balance inflammation via oxidant homeostasis depends on the quality of antioxidants research. Understanding the intersection of two prominent theories for how antioxidants quell inflammation-nutritional hormesis and oxidant scavenging-will enable therapeutic antioxidant use in clinical practice. Purpose: We sought to survey the literature to answer the question: has the hormetic response of exogenous antioxidants been studied in humans and if so, what is its effect Research Design: This review investigates the less well-established theory, nutritional hormesis. To understand the state of hormetic response research, we conducted a literature review describing the relationship between exogenous antioxidants, hormesis, and chronic disease. We used an adaptive search strategy (PubMed and Scopus), retrieving 343 articles, of which 218 were unique. Most studies reviewed the hormetic response in plant and cell models (73.6%) while only 2.2% were in humans. Results: Given the limited robust evidence, clinicians lack research-based guidance on the appropriate therapeutic dose of exogenous antioxidants or, more concerning, supra-physiological dosing via supplements. A critical hurdle in searching the literature is the lack of standardized nomenclature describing the hormetic effect, challenging the ability of clinicians to make informed decisions. Conclusion: Non-human research shows a biphasic, hormetic relationship with antioxidants but observational studies have yet to translate this into the complexities of human biochemistry and physiology. Therefore, we cannot accurately translate this into clinical care. To remedy this insufficiency, we suggest: (1) Improved data collection quality: controlled diet, standardized antioxidant measurements, bioavailability assessed via biomarkers; (2) Larger, harmonized datasets: research subject transparency, keyword standardization, consensus on a hormesis definition.

Factors governing consumers buying behavior concerning nutraceutical product

In recent years, consumers are increasingly attracted to nutraceuticals, an important part of food considered propitious for human health. Therefore, consumers are willingly switching to nutraceuticals and are ready to pay the premium price. This review aims to identify various factors that govern consumer purchasing of nutraceutical products. The outcomes presented in the review provide a closer understanding of consumer attitudes toward buying behavior and their impact on the growth of the global nutraceutical market. The nutraceutical market has been identified depending on the type of nutraceuticals, forms, and regions governing the nutraceutical market. Factors such as health consciousness, knowledge about a product, product availability, price, marketing strategies, and social factors influence consumers' actual buying behavior toward nutraceutical products. A mini survey in Mumbai city of India was conducted to add practical data to the review, and factors affecting consumers' willingness to buy nutraceutical products were identified. It was observed that the decision-making toward buying nutraceutical products was affected by gender, age, education level, and acculturation. It was also identified that the legislation governing nutraceuticals needs to be harmonized throughout many parts of the world, which restricts the growth of this sector to some extent. The findings elucidate that nutraceutical industries should overcome the regulatory barriers and focus on developing innovative products, which will keep current consumers intact and help increase the consumer base and thus expand the nutraceutical market globally.

Auto-STEED: A data mining tool for automated extraction of experimental parameters and risk of bias items from in vivo publications

Background

Systematic reviews, i.e., research summaries that address focused questions in a structured and reproducible manner, are a cornerstone of evidence-based medicine and research. However, certain systematic review steps such as data extraction are labour-intensive which hampers their applicability, not least with the rapidly expanding body of biomedical literature.

Objective

To bridge this gap, we aimed at developing a data mining tool in the R programming environment to automate data extraction from neuroscience in vivo publications. The function was trained on a literature corpus (n=45 publications) of animal motor neuron disease studies and tested in two validation corpora (motor neuron diseases, n=31 publications; multiple sclerosis, n=244 publications).

Results

Our data mining tool Auto-STEED (Automated and STructured Extraction of Experimental Data) was able to extract key experimental parameters such as animal models and species as well as risk of bias items such as randomization or blinding from in vivo studies. Sensitivity and specificity were over 85 and 80%, respectively, for most items in both validation corpora. Accuracy and F-scores were above 90% and 0.9 for most items in the validation corpora. Time savings were above 99%.

Conclusions

Our developed text mining tool Auto-STEED is able to extract key experimental parameters and risk of bias items from the neuroscience in vivo literature. With this, the tool can be deployed to probe a field in a research improvement context or to replace one human reader during data extraction resulting in substantial time-savings and contribute towards automation of systematic reviews. The function is available on Github.

Acute liver failure: A systematic review and network meta-analysis of optimal type of stem cells in animal models

BACKGROUND

The therapeutic effects of various stem cells in acute liver failure (ALF) have been demonstrated in preclinical studies. However, the specific type of stem cells with the highest therapeutic potential has not been determined.

AIM

To validate the efficacy of stem cells in ALF model and to identify the most promising stem cells.

METHODS

A search was conducted on the PubMed, Web of Science, Embase, Scopus, and Cochrane databases from inception to May 3, 2022, and updated on November 16, 2022 to identify relevant studies. Two independent reviewers performed the literature search, identification, screening, quality assessment, and data extraction.

RESULTS

A total of 89 animal studies were included in the analysis. The results of traditional meta-analysis showed that stem cell therapy could significantly reduce the serum levels of alanine aminotransferase [weighted mean difference (WMD) = -181.05 (-191.71, -170.39)], aspartate aminotransferase [WMD = -309.04 (-328.45, -289.63)], tumor necrosis factor-alpha [WMD = -8.75 (-9.93, -7.56)], and interleukin-6 [WMD = -10.43 (-12.11, -8.76)] in animal models of ALF. Further subgroup analysis and network meta-analysis showed that although mesenchymal stem cells are the current research hotspot, the effect of liver stem cells (LSCs) on improving liver function is significantly better than that of the other five types of stem cells. In addition, the ranking results showed that the possibility of LSCs improving liver function ranked first. This fully proves the great therapeutic potential of LSCs, which needs to be paid more attention in the future.

CONCLUSION

LSCs may have a higher therapeutic potential. Further high-quality animal experiments are needed to explore the most effective stem cells for ALF.

Mesenchymal stem cells therapy for acute kidney injury: A systematic review with meta-analysis based on rat model

Objective: To systematically evaluate the efficacy of mesenchymal stem cells (MSCs) for acute kidney injury (AKI) in preclinical studies and to explore the optimal transplantation strategy of MSCs by network meta-analysis with the aim of improving the efficacy of stem cell therapy. Methods: Computer searches of PubMed, Web of Science, Cochrane, Embase, CNKI, Wanfang, VIP, and CBM databases were conducted until 17 August 2022. Literature screening, data extraction and quality evaluation were performed independently by two researchers. Results and Discussion: A total of 50 randomized controlled animal studies were included. The results of traditional meta-analysis showed that MSCs could significantly improve the renal function and injured renal tissue of AKI rats in different subgroups. The results of network meta-analysis showed that although there was no significant difference in the therapeutic effect between different transplant routes and doses of MSCs, the results of surface under the cumulative ranking probability curve (SUCRA) showed that the therapeutic effect of intravenous transplantation of MSCs was better than that of arterial and intrarenal transplantation, and the therapeutic effect of high dose (>1×10⁶) was better than that of low dose (≤1×10⁶). However, the current preclinical studies have limitations in experimental design, measurement and reporting of results, and more high-quality studies, especially direct comparative evidence, are needed in the future to further confirm the best transplantation strategy of MSCs in AKI. Systematic Review Registration: identifier https://CRD42022361199, https://www.crd.york.ac.uk/prospero.

Power and optimal study design in iPSC-based brain disease modelling

Studies using induced pluripotent stem cells (iPSCs) are gaining momentum in brain disorder modelling, but optimal study designs are poorly defined. Here, we compare commonly used designs and statistical analysis for different research aims. Furthermore, we generated immunocytochemical, electrophysiological, and proteomic data from iPSC-derived neurons of five healthy subjects, analysed data variation and conducted power simulations. These analyses show that published case-control iPSC studies are generally underpowered. Designs using isogenic iPSC lines typically have higher power than case-control designs, but generalization of conclusions is limited. We show that, for the realistic settings used in this study, a multiple isogenic pair design increases absolute power up to 60% or requires up to 5-fold fewer lines. A free web tool is presented to explore the power of different study designs, using any (pilot) data.

Perivascular spaces and their role in neuroinflammation

It is uncontested that perivascular spaces play critical roles in maintaining homeostasis and priming neuroinflammation. However, despite more than a century of intense research on perivascular spaces, many open questions remain about the anatomical compartment surrounding blood vessels within the CNS. The goal of this comprehensive review is to summarize the literature on perivascular spaces in human neuroinflammation and associated animal disease models. We describe the cell types taking part in the morphological and functional aspects of perivascular spaces and how those spaces can be visualized. Based on this, we propose a model of the cascade of events occurring during neuroinflammatory pathology. We also discuss current knowledge gaps and limitations of the available evidence. An improved understanding of perivascular spaces could advance our comprehension of the pathophysiology of neuroinflammation and open a new therapeutic window for neuroinflammatory diseases such as multiple sclerosis.

Variability of murine bacterial pneumonia models used to evaluate antimicrobial agents

Antimicrobial resistance has become one of the greatest threats to human health, and new antibacterial treatments are urgently needed. As a tool to develop novel therapies, animal models are essential to bridge the gap between preclinical and clinical research. However, despite common usage of in vivo models that mimic clinical infection, translational challenges remain high. Standardization of in vivo models is deemed necessary to improve the robustness and reproducibility of preclinical studies and thus translational research. The European Innovative Medicines Initiative (IMI)-funded “Collaboration for prevention and treatment of MDR bacterial infections” (COMBINE) consortium, aims to develop a standardized, quality-controlled murine pneumonia model for preclinical efficacy testing of novel anti-infective candidates and to improve tools for the translation of preclinical data to the clinic. In this review of murine pneumonia model data published in the last 10 years, we present our findings of considerable variability in the protocols employed for testing the efficacy of antimicrobial compounds using this in vivo model. Based on specific inclusion criteria, fifty-three studies focusing on antimicrobial assessment against Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii were reviewed in detail. The data revealed marked differences in the experimental design of the murine pneumonia models employed in the literature. Notably, several differences were observed in variables that are expected to impact the obtained results, such as the immune status of the animals, the age, infection route and sample processing, highlighting the necessity of a standardized model.

Animal Models of Choroidal Neovascularization: A Systematic Review

Purpose

Animal models of choroidal neovascularization (CNV) are extensively used to characterize the pathophysiology of chorioretinal diseases with CNV formation and to evaluate novel treatment strategies. This systematic review aims to give a detailed overview of contemporary animal models of CNV.

Methods

A systematic search was performed in PubMed and EMBASE from November 20, 2015, to November 20, 2020, for mammalian animal models of CNV. Following inclusion by two investigators, data from the articles were extracted according to a predefined protocol.

Results

A total of 380 full articles, representing 409 independent animal models, were included. Mice were by far the most utilized animal (76%) followed by rats and non-human primates. The median age of rodents was 8 weeks but with a wide range. Male animals were used in 44% of the studies, but 32% did not report the sex. CNV was laser induced in 89% of the studies, but only 44% of these reported sufficiently on standard laser parameters. Surprisingly, 28% of the studies did not report a sample size for quantitative CNV evaluation. Less than half of the studies performed quantitative in vivo evaluation, and 73% evaluated CNV quantitatively ex vivo. Both in vivo and ex vivo evaluations were conducted primarily at day 7 and/or day 14.

Conclusions

The laser-induced mouse model is the predominant model for experimental CNV. The widespread use of young, healthy male animals may complicate clinical translation, and inadequate reporting challenges reproducibility. Definition and implementation of standardized methodologic and reporting guidelines are attractive.

Questionable Research Practices, Low Statistical Power, and Other Obstacles to Replicability: Why Preclinical Neuroscience Research Would Benefit from Registered Reports

Replicability, the degree to which a previous scientific finding can be repeated in a distinct set of data, has been considered an integral component of institutionalized scientific practice since its inception several hundred years ago. In the past decade, large-scale replication studies have demonstrated that replicability is far from favorable, across multiple scientific fields. Here, I evaluate this literature and describe contributing factors including the prevalence of questionable research practices (QRPs), misunderstanding of p-values, and low statistical power. I subsequently discuss how these issues manifest specifically in preclinical neuroscience research. I conclude that these problems are multifaceted and difficult to solve, relying on the actions of early and late career researchers, funding sources, academic publishers, and others. I assert that any viable solution to the problem of substandard replicability must include changing academic incentives, with adoption of registered reports being the most immediately impactful and pragmatic strategy. For animal research in particular, comprehensive reporting guidelines that document potential sources of sensitivity for experimental outcomes is an essential addition.

Using Noninvasive Electrophysiology to Determine Time Windows of Neuroprotection in Optic Neuropathies

The goal of neuroprotection in optic neuropathies is to prevent loss of retinal ganglion cells (RGCs) and spare their function. The ideal time window for initiating neuroprotective treatments should be the preclinical period at which RGCs start losing their functional integrity before dying. Noninvasive electrophysiological tests such as the Pattern Electroretinogram (PERG) can assess the ability of RGCs to generate electrical signals under a protracted degenerative process in both clinical conditions and experimental models, which may have both diagnostic and prognostic values and provide the rationale for early treatment. The PERG can be used to longitudinally monitor the acute and chronic effects of neuroprotective treatments. User-friendly versions of the PERG technology are now commercially available for both clinical and experimental use.

What Is the Optimal Timing of Transplantation of Neural Stem Cells in Spinal Cord Injury? A Systematic Review and Network Meta-Analysis Based on Animal Studies

Objective

The optimal transplantation timing of neural stem cells in spinal cord injury is fully explored in animal studies to reduce the risk of transformation to clinical practice and to provide valuable reference for future animal studies and clinical research.

Method

Seven electronic databases, namely, PubMed, Web of Science, Embase, Wanfang, Chinese Scientific Journal Database (CSJD-VIP), China Biomedical Literature Database (CBM), and China National Knowledge Infrastructure (CNKI), were searched. The studies were retrieved from inception to November 2021. Two researchers independently screened the literature, extracted data, and evaluated the methodological quality based on the inclusion criteria.

Results and Discussion

Thirty-nine studies were incorporated into the final analyses. Based on the subgroup of animal models and transplantation dose, the results of network meta-analysis showed that the effect of transplantation in the subacute phase might be the best. However, the results of traditional meta-analysis were inconsistent. In the moderate-dose group of moderate spinal cord injury model and the low-dose group of severe spinal cord injury model, transplantation in the subacute phase did not significantly improve motor function. Given the lack of evidence for direct comparison between different transplantation phases, the indirectness of our network meta-analysis, and the low quality of evidence in current animal studies, our confidence in recommending cell transplantation in the subacute phase is limited. In the future, more high-quality, direct comparative studies are needed to explore this issue in depth.

Therapeutic Effect of Exosomes Derived From Stem Cells in Spinal Cord Injury: A Systematic Review Based on Animal Studies

Objective

A systematic review of the role of stem cell-derived exosomes in repairing spinal cord injury (SCI) and the existing problems in animal experiments to provide a reference for better animal experiments and clinical studies in the future.

Method

Three electronic databases, namely PubMed, Web of Science, and Ovid-Embase were searched. The studies were retrieved from inception to October 2021. Two researchers independently screened the literature, extracted data, and evaluated the methodological quality based on the inclusion criteria.

Results and Discussion

Thirty-two studies were incorporated into the final analyses. Exosomes derived from stem cells could not only significantly improve the motor function of animals with SCI, but also significantly increase the expression of anti-inflammatory factors IL-4 and IL-10 and anti-apoptotic protein Bcl-2, while significantly lowering the pro-inflammatory factor IL-1β and TNF-α and the expression of the apoptotic protein BAX. However, the mechanism of exosome-mediated SCI repair, as well as the best source and dosage remain unknown. In addition, there are still some issues with the design, implementation, and reporting of animal experiments in the included studies. Therefore, future research should further standardize the implementation and reporting of animal studies and fully explore the best strategies for exosomes to repair SCI so as to promote the translation of preclinical research results to clinical research better and faster.

Reproducibility, relevance and reliability as barriers to efficient and credible biomedical technology translation

Biomedical research accuracy and relevance for improving healthcare are increasingly identified as costly problems. Basic research data quality, reporting and methodology, and reproducibility are common factors implicated in this challenge. Preclinical models of disease and therapy, largely conducted in rodents, have known deficiencies in replicating most human conditions. Their translation to human results is acknowledged to be poor for decades. Clinical data quality and quantity is also recognized as deficient; gold standard randomized clinical trials are expensive. Few solid conclusions from clinical studies are replicable and many remain unpublished. The translational pathway from fundamental biomedical research through to innovative solutions handed to clinical practitioners is therefore highly inefficient and costly in terms of wasted resources, early claims from fundamental discoveries never witnessed in humans, and few new, improved solutions available clinically for myriad diseases. Improving this biomedical research strategy and resourcing for reliability, translational relevance, reproducibility and clinical impact requires careful analysis and consistent enforcement at both funding and peer review levels.

Target Discovery for Drug Development Using Mendelian Randomization

Making drug development more efficient by identifying promising drug targets can contribute to resource savings. Identifying promising drug targets using human genetic approaches can remove barriers related to translation. In addition, genetic information can be used to identify potentially causal relationships between a drug target and disease. Mendelian randomization (MR) is a class of approaches used to identify causal associations between pairs of genetically predicted traits using data from human genetic studies. MR can be used to prioritize candidate drug targets by predicting disease outcomes and adverse events that could result from the manipulation of a drug target. The theory behind MR is reviewed, including a discussion of MR assumptions, different MR analytical methods, tests for violations of assumptions, and MR methods that can be robust to some violations of MR assumptions. A protocol to perform two-sample MR (2SMR) with summary genome-wide association study (GWAS) results is described. An example of 2SMR examining the causal relationship between low-density lipoprotein (LDL) and coronary artery disease (CAD) is provided as an illustration of the protocol.

The Role of Biodegradable Magnesium and Its Alloys in Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis Based on Animal Studies

Objective: The actual efficacy of magnesium and its alloy in anterior cruciate ligament reconstruction (ACLR) was systematically evaluated to reduce the risk of translation from animal experiments to the clinic.

Methods: Databases of PubMed, Ovid-Embase, Web of Science, CNKI, Wanfang, VIP, and CBM were searched for literature in July 2021. Screening of search results, data extraction, and literature quality evaluation were undertaken independently by two reviewers.

Results and discussion: Seven articles were selected for the meta-analysis. The results showed that the mechanical properties of the femoral-tendon graft–tibia complex fixed with magnesium and its alloys were comparable to those fixed with titanium and its alloys, and magnesium and its alloys were superior to titanium and its alloys in promoting new bone formation. In addition, the unique biodegradability made magnesium and its alloys an orthopedic implant with significant therapeutic potential. However, whether the degradation rate of magnesium and its alloy can match the rate of bone-tendon integration, and whether the bioconjugation of bone-tendon after degradation can meet the exercise load still needs to be explored in further detail. Simultaneously, it is necessary for future research to improve and standardize experimental design, result measurement, etc., so as to minimize the risk of transforming animal experimental results into clinical practice.

A Review of the Current Mammalian Models of Alzheimer's Disease and Challenges That Need to Be Overcome

Alzheimer's disease (AD) is one of the looming health crises of the near future. Increasing lifespans and better medical treatment for other conditions mean that the prevalence of this disease is expected to triple by 2050. The impact of AD includes both the large toll on individuals and their families as well as a large financial cost to society. So far, we have no way to prevent, slow, or cure the disease. Current medications can only alleviate some of the symptoms temporarily. Many animal models of AD have been created, with the first transgenic mouse model in 1995. Mouse models have been beset by challenges, and no mouse model fully captures the symptomatology of AD without multiple genetic mutations and/or transgenes, some of which have never been implicated in human AD. Over 25 years later, many mouse models have been given an AD-like disease and then 'cured' in the lab, only for the treatments to fail in clinical trials. This review argues that small animal models are insufficient for modelling complex disorders such as AD. In order to find effective treatments for AD, we need to create large animal models with brains and lifespan that are closer to humans, and underlying genetics that already predispose them to AD-like phenotypes.

Quantitative cross-species translators of cardiac myocyte electrophysiology: Model training, experimental validation, and applications

Animal experimentation is key in the evaluation of cardiac efficacy and safety of novel therapeutic compounds. However, interspecies differences in the mechanisms regulating excitation-contraction coupling can limit the translation of experimental findings from animal models to human physiology and undermine the assessment of drugs’ efficacy and safety. Here, we built a suite of translators for quantitatively mapping electrophysiological responses in ventricular myocytes across species. We trained these statistical operators using a broad dataset obtained by simulating populations of our biophysically detailed computational models of action potential and Ca2+ transient in mouse, rabbit, and human. We then tested our translators against experimental data describing the response to stimuli, such as ion channel block, change in beating rate, and β-adrenergic challenge. We demonstrate that this approach is well suited to predicting the effects of perturbations across different species or experimental conditions and suggest its integration into mechanistic studies and drug development pipelines.

The laboratory rat: Age and body weight matter

Animal experimentation helps us to understand human biology. Rodents and, in particular, rats are among the most common animals used in animal experiments. Reporting data on animal age, animal body weight, and animal postnatal developmental stages is not consistent, which can cause the failure to translate animal data to humans. This review summarizes age-related postnatal developmental stages in rats by addressing age-related changes in their body weights. The age and body weight of animals can affect drug metabolism, gene expression, metabolic parameters, and other dependent variables measured in animal studies. In addition, considering the age and the body weight of the animals is of particular importance in animal modeling of human diseases. Appropriate reporting of age, body weight, and the developmental stage of animals used in studies can improve animal to human translation.

Biodegradable metals for bone defect repair: A systematic review and meta-analysis based on animal studies

Biodegradable metals are promising candidates for bone defect repair. With an evidence-based approach, this study investigated and analyzed the performance and degradation properties of biodegradable metals in animal models for bone defect repair to explore their potential clinical translation. Animal studies on bone defect repair with biodegradable metals in comparison with other traditional biomaterials were reviewed. Data was carefully collected after identification of population, intervention, comparison, outcome, and study design (PICOS), and following the inclusion criteria of biodegradable metals in animal studies. 30 publications on pure Mg, Mg alloys, pure Zn and Zn alloys were finally included after extraction from a collected database of 2543 publications. A qualitative systematic review and a quantitative meta-analysis were performed. Given the heterogeneity in animal model, anatomical site and critical size defect (CSD), biodegradable metals exhibited mixed effects on bone defect repair and degradation in animal studies in comparison with traditional non-degradable metals, biodegradable polymers, bioceramics, and autogenous bone grafts. The results indicated that there were limitations in the experimental design of the included studies, and quality of the evidence presented by the studies was very low. To enhance clinical translation of biodegradable metals, evidence-based research with data validity is needed. Future studies should adopt standardized experimental protocols in investigating the effects of biodegradable metals on bone defect repair with animal models.

Reflections on chemical risk assessment or how (not) to serve society with science

In this paper, we want to shed light on the demand for chemical and toxicological data growing ever more faster than science can supply and other aspects of assessing chemical risks, including the demand for 'ever greater safety'. The treatise that follows is on the one hand rooted in well-established toxicological theory and on the other hand utilises emerging toxicological insights. Both theoretical conceptions and empirical substantiations are discussed to build up a perspective that produces an outlook on innovation and proliferates insights into our inexorable and invaluable exposure to 'the chemical'. We propose that in toxicology, with the implicit mandatory linear routine of dose-response, there is no tangible scientific drive to understand and unearth the actual empirical dose-response curve for chemicals under scrutiny. This can and should be improved upon as to advance the science of toxicology and to optimise current and future regulatory efforts.

Effect of supplemental prebiotics, probiotics and bioactive proteins on the microbiome composition and fecal calprotectin in C57BL6/j mice

The composition and metabolic activity of the microbiome affect many aspects of health, and there is current interest in dietary constituents that may affect this system. The purpose of this study was to evaluate the effects of a mix of probiotics, a mix of prebiotics and a bioactive protein fraction on the microbiome, when fed to mice alone and in combination at physiologically relevant doses. Mice were fed the total western diet (TWD) supplemented with prebiotics, probiotics, and bioactive proteins individually and in combination for four weeks. Subsequently, effects on the composition of the gut microbiome, gut short-chain fatty acids (SCFAs) concentration, and gut inflammation were measured. Ruminococcus gnavus was increased in mice gut microbiome after feeding prebiotics. Bifidobacterium longum was increased after feeding probiotics. The treatments significantly affected beta-diversity with minor treatment effects on cecal or fecal SCFAs levels, and the treatments did not affect gut inflammation as measured by fecal calprotectin.

Biodegradable metals for bone fracture repair in animal models: a systematic review

Biodegradable metals hold promises for bone fracture repair. Their clinical translation requires pre-clinical evaluations including animal studies, which demonstrate the safety and performance of such materials prior to clinical trials. This evidence-based study investigates and analyzes the performance of bone fractures repair as well as degradation properties of biodegradable metals in animal models. Data were carefully collected after identification of population, interventions, comparisons, outcomes and study design, as well as inclusion criteria combining biodegradable metals and animal study. Twelve publications on pure Mg, Mg alloys and Zn alloys were finally included and reviewed after extraction from a collected database of 2122 publications. Compared to controls of traditional non-degradable metals or resorbable polymers, biodegradable metals showed mixed or contradictory outcomes of fracture repair and degradation in animal models. Although quantitative meta-analysis cannot be conducted because of the data heterogeneity, this systematic review revealed that the quality of evidence for biodegradable metals to repair bone fractures in animal models is 'very low'. Recommendations to standardize the animal studies of biodegradable metals were proposed. Evidence-based biomaterials research could help to both identify reliable scientific evidence and ensure future clinical translation of biodegradable metals for bone fracture repair.

Gap Analysis of Swine-Based Hemostasis Research: "Houses of Brick or Mansions of Straw?"

INTRODUCTION

Hemorrhage control is the top priority in far-forward care. Preclinical studies are essential for determining safety and efficacy before novel therapeutics can be tested in humans. Unfortunately, poor methodological quality jeopardizes translational potential.

METHODS

We systematically reviewed 136 recent publications describing swine models of hemostasis and hemorrhage reduction to assess compliance with established standards for scientific reporting. Quality measures were summarized by descriptive statistics; randomization was assessed by using baseline group differences to test the uniform distribution assumption for observed P-values.

RESULTS

Most articles did not report information essential to assess study validity and reliability of experimental results. Studies claiming random allocation showed clear evidence of systematic bias. Sample sizes were small, but nearly all studies reported statistically significant effects in the direction of "benefit." Excessive hypothesis testing increased the risk of false positives.

CONCLUSIONS

Methodological quality was poor. Although funding agencies actively promote good scientific practice, investigators have been slow to comply. Poorly executed and reported animal research is an ethical and translational issue, wasting animals and potentially harming patients. To properly assess the therapeutic benefit of novel interventions, investigators must rely less on rote hypothesis testing, develop skills in experimental design and quantitative analysis, and comply with best-practice reporting guidelines.

Variability and sex-dependence of hypothermic neuroprotection in a rat model of neonatal hypoxic-ischaemic brain injury: a single laboratory meta-analysis

Therapeutic hypothermia (HT) is standard care for term infants with hypoxic–ischaemic (HI) encephalopathy. However, the efficacy of HT in preclinical models, such as the Vannucci model of unilateral HI in the newborn rat, is often greater than that reported from clinical trials. Here, we report a meta-analysis of data from every experiment in a single laboratory, including pilot data, examining the effect of HT in the Vannucci model. Across 21 experiments using 106 litters, median (95% CI) hemispheric area loss was 50.1% (46.0–51.9%; n = 305) in the normothermia group, and 41.3% (35.1–44.9%; n = 317) in the HT group, with a bimodal injury distribution. Median neuroprotection by HT was 17.6% (6.8–28.3%), including in severe injury, but was highly-variable across experiments. Neuroprotection was significant in females (p < 0.001), with a non-significant benefit in males (p = 0.07). Animals representing the median injury in each group within each litter (n = 277, 44.5%) were also analysed using formal neuropathology, which showed neuroprotection by HT throughout the brain, particularly in females. Our results suggest an inherent variability and sex-dependence of the neuroprotective response to HT, with the majority of studies in the Vannucci model vastly underpowered to detect true treatment effects due to the distribution of injury.

Modeling human prostate cancer progression in vitro

Detailed mechanisms involved in prostate cancer (CaP) development and progression are not well understood. Current experimental models used to study CaP are not well suited to address this issue. Previously, we have described the hormonal progression of non-tumorigenic human prostate epithelial cells (BPH1) into malignant cells via tissue recombination. Here, we describe a method to derive human cell lines from distinct stages of CaP that parallel cellular, genetic and epigenetic changes found in patients with cancers. This BPH1-derived Cancer Progression (BCaP) model represents different stages of cancer. Using diverse analytical strategies, we show that the BCaP model reproduces molecular characteristics of CaP in human patients. Furthermore, we demonstrate that BCaP cells have altered gene expression of shared pathways with human and transgenic mouse CaP data, as well as, increasing genomic instability with TMPRSS2-ERG fusion in advanced tumor cells. Together, these cell lines represent a unique model of human CaP progression providing a novel tool that will allow the discovery and experimental validation of mechanisms regulating human CaP development and progression. This BPH1-derived Cancer Progression (BCaP) model represents different stages of cancer. The BCaP model reproduces molecular characteristics of prostate cancer. The cells have altered gene expression with TMPRSS2-ERG fusion representing a unique model for prostate cancer progression.

Evolving challenges to model human diseases for translational research

Animal models are a significant component of biomedical research and play an important role in translational studies. Traditionally, rodent models have been the mainstay and principal choice of researchers but in recent years, there have been significant changes in the landscape of animal modeling. For example, newer techniques have greatly expanded the use and successful application of large animal models such as pigs for translational studies. The evolving types and species of animal models can influence the research landscape in terms of facilities, expertise, reproducibility and funding streams, which creates new challenges for research studies. It is also important that investigators are prepared to address the necessity of their animal model research and capable to educate the public regarding its value.

Food matrix and the microbiome: considerations for preclinical chronic disease studies

Animal models of chronic disease are continuously being refined and have evolved with the goal of increasing the translation of results to human populations. Examples of this progress include transgenic models and germ-free animals conventionalized with human microbiota. The gut microbiome is involved in the etiology of several chronic diseases. Therefore, consideration of the experimental conditions that may affect the gut microbiome in preclinical disease is very important. Of note, diet plays a large role in shaping the gut microbiome and can be a source of variation between animal models and human populations. Traditionally, nutrition researchers have focused on manipulating the macronutrient profile of experimental diets to model diseases such as metabolic syndrome. However, other dietary components found in human foods, but not in animal diets, can have sizable effects on the composition and metabolic capacity of the gut microbiome and, as a consequence, manifestation of the chronic disease being modeled. The purpose of this review is to describe how food matrix food components, including diverse fiber sources, oxidation products from cooking, and dietary fat emulsifiers, shape the composition of the gut microbiome and influence gut health.

Menagerie: A text-mining tool to support animal-human translation in neurodegeneration research

Discovery studies in animals constitute a cornerstone of biomedical research, but suffer from lack of generalizability to human populations. We propose that large-scale interrogation of these data could reveal patterns of animal use that could narrow the translational divide. We describe a text-mining approach that extracts translationally useful data from PubMed abstracts. These comprise six modules: species, model, genes, interventions/disease modifiers, overall outcome and functional outcome measures. Existing National Library of Medicine natural language processing tools (SemRep, GNormPlus and the Chemical annotator) underpin the program and are further augmented by various rules, term lists, and machine learning models. Evaluation of the program using a 98-abstract test set achieved F1 scores ranging from 0.75-0.95 across all modules, and exceeded F1 scores obtained from comparable baseline programs. Next, the program was applied to a larger 14,481 abstract data set (2008-2017). Expected and previously identified patterns of species and model use for the field were obtained. As previously noted, the majority of studies reported promising outcomes. Longitudinal patterns of intervention type or gene mentions were demonstrated, and patterns of animal model use characteristic of the Parkinson's disease field were confirmed. The primary function of the program is to overcome low external validity of animal model systems by aggregating evidence across a diversity of models that capture different aspects of a multifaceted cellular process. Some aspects of the tool are generalizable, whereas others are field-specific. In the initial version presented here, we demonstrate proof of concept within a single disease area, Parkinson's disease. However, the program can be expanded in modular fashion to support a wider range of neurodegenerative diseases.

Limitations of Animal Studies for Predicting Toxicity in Clinical Trials: Is it Time to Rethink Our Current Approach?

Animal testing is used in pharmaceutical and industrial research to predict human toxicity, and yet analysis suggests that animal models are poor predictors of drug safety in humans. The cost of animal research is high-in dollars, delays in drug approval, and in the loss of potentially beneficial drugs for human use. Human subjects have been harmed in the clinical testing of drugs that were deemed safe by animal studies. Increasingly, investigators are questioning the scientific merit of animal research. This review discusses issues in using animals to predict human toxicity in pharmaceutical development. Part 1 focuses on scientific concerns over the validity of animal research. Part 2 will discuss alternatives to animal research and their validation and use in production of human pharmaceuticals.

Use of Human Pluripotent Stem Cells to Define Initiating Molecular Mechanisms of Cataract for Anti-Cataract Drug Discovery

Cataract is a leading cause of blindness worldwide. Currently, restoration of vision in cataract patients requires surgical removal of the cataract. Due to the large and increasing number of cataract patients, the annual cost of surgical cataract treatment amounts to billions of dollars. Limited access to functional human lens tissue during the early stages of cataract formation has hampered efforts to develop effective anti-cataract drugs. The ability of human pluripotent stem (PS) cells to make large numbers of normal or diseased human cell types raises the possibility that human PS cells may provide a new avenue for defining the molecular mechanisms responsible for different types of human cataract. Towards this end, methods have been established to differentiate human PS cells into both lens cells and transparent, light-focusing human micro-lenses. Sensitive and quantitative assays to measure light transmittance and focusing ability of human PS cell-derived micro-lenses have also been developed. This review will, therefore, examine how human PS cell-derived lens cells and micro-lenses might provide a new avenue for development of much-needed drugs to treat human cataract.

Nasal Administration and Plasma Pharmacokinetics of Parathyroid Hormone Peptide PTH 1-34 for the Treatment of Osteoporosis

Nasal delivery of large peptides such as parathyroid 1-34 (PTH 1-34) can benefit from a permeation enhancer to promote absorption across the nasal mucosa into the bloodstream. Previously, we have published an encouraging bioavailability (78%), relative to subcutaneous injection in a small animal preclinical model, for a liquid nasal spray formulation containing the permeation enhancer polyethylene glycol (15)-hydroxystearate (Solutol^® HS15). We report here the plasma pharmacokinetics of PTH 1-34 in healthy human volunteers receiving the liquid nasal spray formulation containing Solutol^® HS15. For comparison, data for a commercially manufactured teriparatide formulation delivered via subcutaneous injection pen are also presented. Tc-99m-DTPA gamma scintigraphy monitored the deposition of the nasal spray in the nasal cavity and clearance via the inferior meatus and nasopharynx. The 50% clearance time was 17.8 min (minimum 10.9, maximum 74.3 min). For PTH 1-34, mean plasma C_max of 5 pg/mL and 253 pg/mL were obtained for the nasal spray and subcutaneous injection respectively; relative bioavailability of the nasal spray was ≤1%. Subsequently, we investigated the pharmacokinetics of the liquid nasal spray formulation as well as a dry powder nasal formulation also containing Solutol^® HS15 in a crossover study in an established ovine model. In this preclinical model, the relative bioavailability of liquid and powder nasal formulations was 1.4% and 1.0% respectively. The absolute bioavailability of subcutaneously administered PTH 1-34 (mean 77%, range 55-108%) in sheep was in agreement with published human data for teriparatide (up to 95%). These findings have important implications in the search for alternative routes of administration of peptides for the treatment of osteoporosis, and in terms of improving translation from animal models to humans.

Recapitulating Parkinson's disease pathology in a three-dimensional human neural cell culture model

Extensive loss of dopaminergic neurons and aggregation of the protein α-synuclein into ubiquitin-positive Lewy bodies represents a major neuropathological hallmark of Parkinson's disease (PD). At present, the generation of large nuclear-associated Lewy bodies from endogenous wild-type α-synuclein, translationally regulated under its own promoter in human cell culture models, requires costly and time-consuming protocols. Here, we demonstrate that fully differentiated human SH-SY5Y neuroblastoma cells grown in three-dimensional cell culture develop Lewy-body-like pathology upon exposure to exogenous α-synuclein species. In contrast to most cell- and rodent-based PD models, which exhibit multiple diffuse α-synuclein aggregates throughout the cytoplasm, a single large nuclear inclusion that is immunopositive for α-synuclein and ubiquitin is rapidly obtained in our model. This was achieved without the need for overexpression of α-synuclein or genetic modification of the cell line. However, phosphorylation of α-synuclein within these inclusions was not observed. The system described here provides an ideal tool to screen compounds to therapeutically intervene in Lewy body formation, and to investigate the mechanisms involved in disease progression in synucleinopathies.

The effects of microdose LSD on time perception: a randomised, double-blind, placebo-controlled trial

RATIONALE

Previous research demonstrating that lysergic acid diethylamide (LSD) produces alterations in time perception has implications for its impact on conscious states and a range of psychological functions that necessitate precise interval timing. However, interpretation of this research is hindered by methodological limitations and an inability to dissociate direct neurochemical effects on interval timing from indirect effects attributable to altered states of consciousness.

METHODS

We conducted a randomised, double-blind, placebo-controlled study contrasting oral administration of placebo with three microdoses of LSD (5, 10, and 20 μg) in older adults. Subjective drug effects were regularly recorded and interval timing was assessed using a temporal reproduction task spanning subsecond and suprasecond intervals.

RESULTS

LSD conditions were not associated with any robust changes in self-report indices of perception, mentation, or concentration. LSD reliably produced over-reproduction of temporal intervals of 2000 ms and longer with these effects most pronounced in the 10 μg dose condition. Hierarchical regression analyses indicated that LSD-mediated over-reproduction was independent of marginal differences in self-reported drug effects across conditions.

CONCLUSIONS

These results suggest that microdose LSD produces temporal dilation of suprasecond intervals in the absence of subjective alterations of consciousness.

Virulence of Marburg Virus Angola Compared to Mt. Elgon (Musoke) in Macaques: A Pooled Survival Analysis

Angola variant (MARV/Ang) has replaced Mt. Elgon variant Musoke isolate (MARV/MtE-Mus) as the consensus standard variant for Marburg virus research and is regarded as causing a more aggressive phenotype of disease in animal models; however, there is a dearth of published evidence supporting the higher virulence of MARV/Ang. In this retrospective study, we used data pooled from eight separate studies in nonhuman primates experimentally exposed with either 1000 pfu intramuscular (IM) MARV/Ang or MARV/MtE-Mus between 2012 and 2017 at the United States Army Medical Research Institute of Infectious Diseases (USAMRIID). Multivariable Cox proportional hazards regression was used to evaluate the association of variant type with time to death, the development of anorexia, rash, viremia, and 10 select clinical laboratory values. A total of 47 cynomolgus monkeys were included, of which 18 were exposed to MARV/Ang in three separate studies and 29 to MARV/MtE-Mus in five studies. Following universally fatal Marburg virus exposure, compared to MARV/MtE-Mus, MARV/Ang was associated with an increased risk of death (HR = 22.10; 95% CI: 7.08, 68.93), rash (HR = 5.87; 95% CI: 2.76, 12.51) and loss of appetite (HR = 35.10; 95% CI: 7.60, 162.18). Our data demonstrate an increased virulence of MARV/Ang compared to MARV/MtE-Mus variant in the 1000 pfu IM cynomolgus macaque model.

Comparison of Aerosol- and Percutaneous-acquired Venezuelan Equine Encephalitis in Humans and Nonhuman Primates for Suitability in Predicting Clinical Efficacy under the Animal Rule

Licensure of medical countermeasure vaccines to protect against aerosolized Venezuelan equine encephalitis virus (VEEV) requires the use of the Animal Rule to assess vaccine efficacy, because human studies are not feasible or ethical. We therefore performed a retrospective study of VEE cases that occurred in at-risk laboratory workers and support personnel during the United States Biowarfare Program (1943-1969) to better define percutaneous- and aerosol-acquired VEE in humans and to compare these results with those described for the NHP model (in which high-dose aerosol VEEV challenge led to more severe encephalitis than parenteral challenge). Record review and analysis of 17 aerosol- and 23 percutaneous-acquired human cases of VEE included incubation period, symptoms, physical examination findings, and markers of infection. Human VEE disease by both exposure routes presented as acute febrile illness, typically with fever, chills, headache, back pain, malaise, myalgia, anorexia, and nausea. Aerosol exposure more commonly led to upper respiratory tract-associated findings of sore throat (59% compared with 26%), pharyngeal erythema (76% compared with 52%), neck pain (29% compared with 4%), and cervical lymphadenopathy (29% compared with 4%). Other disease manifestations, including encephalitis, were similar between the 2 exposure groups. The increase in upper respiratory tract findings in aerosol-acquired VEE in humans has not previously been reported but is supported by the mouse model, which showed nasal mucosal necrosis, necrotizing rhinitis, and an increase in upper respiratory tract viral burden associated with aerosol VEEV challenge. Fever, viremia, and lymphopenia were common markers of VEE disease in both humans and NHP, regardless of the exposure route. Taken collectively, our findings provide support for use of the nonlethal NHP model for advanced development of medical countermeasures against aerosol- or percutaneous-acquired VEE.

Retrospective harm benefit analysis of pre-clinical animal research for six treatment interventions

BACKGROUND

The harm benefit analysis (HBA) is the cornerstone of animal research regulation and is considered to be a key ethical safeguard for animals. The HBA involves weighing the anticipated benefits of animal research against its predicted harms to animals but there are doubts about how objective and accountable this process is.

OBJECTIVES

i. To explore the harms to animals involved in pre-clinical animal studies and to assess these against the benefits for humans accruing from these studies; ii. To test the feasibility of conducting this type of retrospective HBA.

METHODS

Data on harms were systematically extracted from a sample of pre-clinical animal studies whose clinical relevance had already been investigated by comparing systematic reviews of the animal studies with systematic reviews of human studies for the same interventions (antifibrinolytics for haemorrhage, bisphosphonates for osteoporosis, corticosteroids for brain injury, Tirilazad for stroke, antenatal corticosteroids for neonatal respiratory distress and thrombolytics for stroke). Clinical relevance was also explored in terms of current clinical practice. Harms were categorised for severity using an expert panel. The quality of the research and its impact were considered. Bateson's Cube was used to conduct the HBA.

RESULTS

The most common assessment of animal harms by the expert panel was 'severe'. Reported use of analgesia was rare and some animals (including most neonates) endured significant procedures with no, or only light, anaesthesia reported. Some animals suffered iatrogenic harms. Many were kept alive for long periods post-experimentally but only 1% of studies reported post-operative care. A third of studies reported that some animals died prior to endpoints. All the studies were of poor quality. Having weighed the actual harms to animals against the actual clinical benefits accruing from these studies, and taking into account the quality of the research and its impact, less than 7% of the studies were permissible according to Bateson's Cube: only the moderate bisphosphonate studies appeared to minimise harms to animals whilst being associated with benefit for humans.

CONCLUSIONS

This is the first time the accountability of the HBA has been systematically explored across a range of pre-clinical animal studies. The regulatory systems in place when these studies were conducted failed to safeguard animals from severe suffering or to ensure that only beneficial, scientifically rigorous research was conducted. Our findings indicate a pressing need to: i. review regulations, particularly those that permit animals to suffer severe harms; ii. reform the processes of prospectively assessing pre-clinical animal studies to make them fit for purpose; and iii. systematically evaluate the benefits of pre-clinical animal research to permit a more realistic assessment of its likely future benefits.

Nictitating membrane fixation improves stability of the contact lens on the animal corneal surface

We evaluated the feasibility and safety of nictitating membrane fixation to address reduced contact lens stability by the nictitating membrane in a rabbit model. Under general anesthesia, twelve animals received a horizontal mattress suture between the nictitating membrane and the upper eyelid of one eye. To assess the effects of this technique and secondary side effects, contact lens stability test, Schirmer tear test, tear break-up time measurement, eye tissue pathology and morphology were evaluated. Contact lens stability was increased after nictitating membrane fixation. The percentage of contact lens retention in the nictitating membrane fixed rabbit after 4 hours was 90% whereas that in the untreated rabbit was 42.5%. In addition, there were no significant differences in tear quantity and quality between the fixed and untreated eyes. Furthermore, no remarkable pathological lesions were found in gross observation during the 1-month time period or the following pathological examination. In this study, we demonstrated that nictitating membrane fixation increases contact lens stability without specific side effects using a rabbit model. This minimally invasive procedure could be useful when designing animal models for testing new contact lenses and has potential to apply to other biomaterial research on the ocular surface.

Novel targets and future strategies for acute cardioprotection: Position Paper of the European Society of Cardiology Working Group on Cellular Biology of the Heart

Ischaemic heart disease and the heart failure that often results, remain the leading causes of death and disability in Europe and worldwide. As such, in order to prevent heart failure and improve clinical outcomes in patients presenting with an acute ST-segment elevation myocardial infarction and patients undergoing coronary artery bypass graft surgery, novel therapies are required to protect the heart against the detrimental effects of acute ischaemia/reperfusion injury (IRI). During the last three decades, a wide variety of ischaemic conditioning strategies and pharmacological treatments have been tested in the clinic-however, their translation from experimental to clinical studies for improving patient outcomes has been both challenging and disappointing. Therefore, in this Position Paper of the European Society of Cardiology Working Group on Cellular Biology of the Heart, we critically analyse the current state of ischaemic conditioning in both the experimental and clinical settings, provide recommendations for improving its translation into the clinical setting, and highlight novel therapeutic targets and new treatment strategies for reducing acute myocardial IRI.

The Ebola clinical trials: a precedent for research ethics in disasters

The West African Ebola epidemic has set in motion a collective endeavour to conduct accelerated clinical trials, testing unproven but potentially lifesaving interventions in the course of a major public health crisis. This unprecedented effort was supported by the recommendations of an ad hoc ethics panel convened in August 2014 by the WHO. By considering why and on what conditions the exceptional circumstances of the Ebola epidemic justified the use of unproven interventions, the panel's recommendations have challenged conventional thinking about therapeutic development and clinical research ethics. At the same time, unanswered ethical questions have emerged, in particular: (i) the specification of exceptional circumstances, (ii) the specification of unproven interventions, (iii) the goals of interventional research in terms of individual versus collective interests, (iv) the place of adaptive trial designs and (v) the exact meaning of compassionate use with unapproved interventions. Examination of these questions, in parallel with empirical data from research sites, will help build pragmatic foundations for disaster research ethics. Furthermore, the Ebola clinical trials signal an evolution in the current paradigms of therapeutic research, beyond the case of epidemic emergencies.

Animal Models in Translational Research: Rosetta Stone or Stumbling Block?

Leading animal models are powerful tools for translational research, but they also present obstacles. Poorly conducted preclinical research in animals is a common cause of translational failure, but even when such research is well-designed and carefully executed, challenges remain. In particular, dominant models may bias research directions, elide essential aspects of human disease, omit important context, or subtly shift research targets. Recognizing these stumbling blocks can help us find ways to avoid them: employing a wider range of models, incorporating more realistic environmental conditions, better aligning studies between animals and patients, and focusing on human biology and therapeutic goals. Such changes are costly; but insisting it would be impractical or unrealistic to change strategies offers no way out of the current impasse. Rather, we must acknowledge the obstacles as well as the advantages presented by core models, and direct some of our investments in translational research toward getting around them.

Animal 'models': How a mechanistic approach can reduce suffering and improve translatability

Poorly predictive animal models of disease cause avoidable suffering and hamper the discovery of new treatments for patients. A focus on mechanistic modelling has the potential to reduce animal suffering as well as improving translation from the bench to the bedside.

Epigenetics Changes Nothing: What a New Scientific Field Does and Does Not Mean for Ethics and Social Justice

Recently, ethicists have posited that consideration of epigenetic mechanisms presents novel challenges to concepts of justice and equality of opportunity, such as elevating the importance of environments in bioethics and providing a counterpoint to gross genetic determinism. We argue that new findings in epigenetic sciences, including those regarding intergenerational health effects, do not necessitate reconceptualization of theories of justice or the environment. To the contrary, such claims reflect a flawed understanding of epigenetics and its relation to genetics that may unintentionally undermine appeals to social justice. We provide a brief summary of epigenetic sciences, focusing on phenomena central to the current ethical discourse. We identify three fallacious modes of reasoning arising from the emergent literature on the ethical and policy implications of epigenetics, including mischaracterization, undue extrapolation, and exceptionalism. We end by discussing how these issues may work against mobilizing health equity policies and present a more modest claim regarding the value of new epigenetic knowledge to health justice by setting this discourse within the context of known themes in biomedical ethics and health policy.