The Reduced Uterine Perfusion Pressure as a model for preeclampsia and fetal growth restriction in murine: a systematic review and meta-analysis

BACKGROUND

The Reduced Uterine Perfusion Pressure (RUPP) model is frequently used to study preeclampsia and fetal growth restriction. An improved understanding of influential factors might improve reproducibility and reduce animal use considering the variability in RUPP phenotype.

METHOD

We performed a systematic review and meta-analysis by searching Medline and Embase (until 03-28-2023) for RUPP studies in murine. Primary outcomes included: maternal blood pressure (BP) or proteinuria, fetal weight or crown-rump-length, fetal reabsorptions, or anti-angiogenic factors. We aimed to identify influential factors by meta-regression analysis.

RESULTS

We included 155 studies. Our meta-analysis showed that the RUPP procedure results in significantly higher BP (MD 24.1 mmHg; [22.6;25.7]; n=148), proteinuria (SMD 2.3; [0.9; 3.8]; n=28), fetal reabsorptions (MD 50.4%; [45.5; 55.2]; n=42), circulating soluble FMS-like tyrosine kinase-1 (sFlt-1) (SMD 2.6; [1.7; 3.4]; n=34), and lower fetal weight (MD -0.4 g; [-0.47; -0.34]; n=113. The heterogeneity (variability between studies) in primary outcomes appeared ≥90%. Our meta-regression identified influential factors in the method and time point of BP measurement, randomization in fetal weight, and type of control group in sFlt-1.

DISCUSSION

The RUPP is a robust model considering the evident differences in maternal and fetal outcomes. The high heterogeneity reflects the observed variability in phenotype. Due to underreporting, we observed reporting bias and a high risk of bias. We recommend standardizing study design by optimal time point and method chosen for readout measures to limit the variability. This contributes to improved reproducibility and thereby eventually improves the translational value of the RUPP model.

The effect of bone marrow derived cell therapies on hind limb perfusion, A systematic review and meta-analysis

BACKGROUND

Administration of bone marrow (BM) derived cells to restore perfusion showed promising results in preclinical studies. However, clinical studies in chronic limb threatening ischemia (CLTI) demonstrated conflicting results. We conducted a systematic review and meta-analysis on preclinical studies to assess the efficacy of BM-derived cell administration in restoring relative perfusion in the hind limb ischemia model (HLI) and identify possible determinants of therapeutic efficacy.

METHODS

In vivo animal studies that assessed BM MNCs or BM MSCs in the HLI model and included relative perfusion as an outcome measure were identified using a systematic search in PubMed and EMBASE on January 10th, 2022. Risk of bias was assessed using SYRCLE's risk of bias tool. Study characteristics and outcome data on relative perfusion were extracted. A random effects meta-analysis was performed using the mean difference calculated from the maximum relative perfusion for each study arm in each study.

RESULTS

85 studies that comprised 1053 animals were included. Our meta-analysis shows a significant increase in perfusion in the affected limb after BM cell administration compared to the control (effect size 18.3 (95% CI 15.9 - 20.7, p<0.001). However, we observed a high heterogeneity between studies (I2 91%), which could not be explained by dose, species, cell type or administration route. The risk of several types of bias was unclear due to incomplete reporting. We also detected a substantial risk of publication bias in this evidence base.

DISCUSSION

There is a beneficial effect of BM-derived cell therapy in animal models for CLTI. However, the certainty of the evidence is low according to GRADE assessment. Translational implementation of this method should take this into account.

Effects of postnatal corticosteroids on lung development in newborn animals. A systematic review

BACKGROUND

Postnatal systemic corticosteroids reduce the risk of bronchopulmonary dysplasia but the effect depends on timing, dosing, and type of corticosteroids. Animal studies may provide valuable information on these variable effects. This systematic review summarizes the effects of postnatal systemic corticosteroids on lung development in newborn animals.

METHODS

A systematic search was performed in PubMed and Embase in December 2022. The protocol was published on PROSPERO (CRD42021177701).

RESULTS

Of the 202 eligible studies, 51 were included. Only newborn rodent studies met the inclusion criteria. Most studies used dexamethasone (98%). There was huge heterogeneity in study outcome measures and corticosteroid treatment regimens. Reporting of study quality indicators was mediocre and risk of bias was unclear due to poor reporting of study methodology. Meta-analysis showed that postnatal corticosteroids caused a decrease in body weight as well as persistent alveolar simplification. Subgroup analyses revealed that healthy animals were most affected.

CONCLUSION

In newborn rodents, postnatal systemic corticosteroids have a persistent negative effect on body weight and lung development. There was huge heterogeneity in experimental models, mediocre study quality, unclear risk of bias, and very small subgroups for meta-analysis which limited firm conclusions.

IMPACT

Postnatal corticosteroids reduce the risk of bronchopulmonary dysplasia but the effect depends on timing, dosing, and type of corticosteroids while the underlying mechanism of this variable effect is unknown. This is the first systematic review and meta-analysis of preclinical newborn animal studies reviewing the effect of postnatal systemic corticosteroids on lung development. In newborn rodent models, postnatal corticosteroids have a persistent negative effect on body weight and lung alveolarization, especially in healthy animals.

Navigating PROSPERO4animals: 10 top tips for efficient pre-registration of your animal systematic review protocol

Systematic reviews are an essential tool in identifying knowledge gaps and synthesizing evidence from in vivo animal research to improve human health. The review process follows an explicit and systematic methodology to minimize bias, but is not immune to biases or methodological flaws. Pre-registering a systematic review protocol has several benefits, including avoiding unplanned duplication of reviews, reducing reporting biases, and providing structure throughout the review process. It also helps to align the opinions of review team members and can shield researchers from post-hoc critique. PROSPERO4animals is the international prospective register of systematic reviews (PROSPERO) for the preregistration of systematic review of animal studies. As administrators, here we provide 10 tips to facilitate pre-registration in PROSPERO4animals. These tips address common difficulties that both beginners and experienced researchers may face when pre-registering their systematic review protocols. This article aims to help authors write and register a detailed systematic review protocol on PROSPERO4animals.

"I did not expect the doctor to treat a ghost": a systematic review of published reports regarding chronic postamputation pain in British First World War veterans

Limb trauma remains the most prevalent survivable major combat injury. In the First World War, more than 700,000 British soldiers received limb wounds and more than 41,000 underwent an amputation, creating one of the largest amputee cohorts in history. Postamputation pain affects up to 85% of military amputees, suggesting that up to 33,000 British First World War veterans potentially reported postamputation pain. This qualitative systematic review explores the professional medical conversation around clinical management of chronic postamputation pain in this patient cohort, its development over the 20th century, and how this information was disseminated among medical professionals. We searched The Lancet and British Medical Journal archives (1914-1985) for reports referring to postamputation pain, its prevalence, mechanisms, descriptors, or clinical management. Participants were First World War veterans with a limb amputation, excluding civilians and veterans of all other conflicts. The search identified 9809 potentially relevant texts, of which 101 met the inclusion criteria. Reports emerged as early as 1914 and the discussion continued over the next 4 decades. Unexpected findings included early advocacy of multidisciplinary pain management, concerns over addiction, and the effect of chronic pain on mental health emerging decades earlier than previously thought. Chronic postamputation pain is still a significant issue for military rehabilitation. Similarities between injury patterns in the First World War and recent Iraq and Afghanistan conflicts mean that these historical aspects remain relevant to today's military personnel, clinicians, researchers, and policymakers.

Pharmacological modulation of conditioned fear in the fear-potentiated startle test: a systematic review and meta-analysis of animal studies

RATIONALE AND OBJECTIVES

Fear conditioning is an important aspect in the pathophysiology of anxiety disorders. The fear-potentiated startle test is based on classical fear conditioning and over the years, a broad range of drugs have been tested in this test. Synthesis of the available data may further our understanding of the neurotransmitter systems that are involved in the expression of conditioned fear.

METHODS

Following a comprehensive search in Medline and Embase, we included 68 research articles that reported on 103 drugs, covering 56 different drug classes. The systematic review was limited to studies using acute, systemic drug administration in naive animals.

RESULTS

Qualitative data synthesis showed that most clinically active anxiolytics, but not serotonin-reuptake inhibitors, reduced cued fear. Anxiogenic drugs increased fear potentiation in 35% of the experiments, reduced fear potentiation in 29% of the experiments, and were without effect in 29% of the experiments. Meta-analyses could be performed for five drug classes and showed that benzodiazepines, buspirone, 5-HT1A agonists, 5-HT1A antagonists, and mGluR2,3 agonists reduced cued conditioned fear. The non-cued baseline startle response, which may reflect contextual anxiety, was only significantly reduced by benzodiazepines and 5-HT1A antagonists. No associations were found between drug effects and methodological characteristics, except for strain.

CONCLUSIONS

The fear-potentiated startle test appears to have moderate to high predictive validity and may serve as a valuable tool for the development of novel anxiolytics. Given the limited available data, the generally low study quality and high heterogeneity additional studies are warranted to corroborate the findings of this review.

Designing, conducting, and reporting reproducible animal experiments

In biomedicine and many other fields, there are growing concerns around the reproducibility of research findings, with many researchers being unable to replicate their own or others' results. This raises important questions as to the validity and usefulness of much published research. In this review, we aim to engage researchers in the issue of research reproducibility and equip them with the necessary tools to increase the reproducibility of their research. We first highlight the causes and potential impact of non-reproducible research and emphasise the benefits of working reproducibly for the researcher and broader research community. We address specific targets for improvement and steps that individual researchers can take to increase the reproducibility of their work. We next provide recommendations for improving the design and conduct of experiments, focusing on in vivo animal experiments. We describe common sources of poor internal validity of experiments and offer practical guidance for limiting these potential sources of bias at different experimental stages, as well as discussing other important considerations during experimental design. We provide a list of key resources available to researchers to improve experimental design, conduct, and reporting. We then discuss the importance of open research practices such as study preregistration and the use of preprints and describe recommendations around data management and sharing. Our review emphasises the importance of reproducible work and aims to empower every individual researcher to contribute to the reproducibility of research in their field.

A systematic review of the Woven EndoBridge device-do findings in pre-clinical animal models compare to clinical results?

BACKGROUND

The Woven Endobridge (WEB) is designed to treat intracranial wide-neck bifurcation aneurysms, preventing subarachnoid hemorrhage. The translational value of animal models used for WEB device testing is unknown. With this systematic review, we aim to identify the existing animal models used in testing the WEB device and compare the efficacy and safety outcomes to those of prospective clinical studies.

METHODS

This study was funded by ZonMw: project number 114024133. A comprehensive search was performed in PubMed and in EMBASE via the Ovid interface. The following exclusion criteria were used: 1) not an original full-length research paper, 2) not an in vivo animal study or a human study, 3) no WEB implantation, 4) if in humans: not a prospective study. The SYRCLE risk of bias tool (animal studies) and the Newcastle-Ottawa quality assessment scale for cohort studies (clinical studies) were used to assess risks of bias. A narrative synthesis was performed.

RESULTS

Six animal studies and 17 clinical studies met the inclusion criteria. The rabbit elastase aneurysm model was the only animal model used to assess WEB device performance. Safety outcomes were never reported in animal studies. Efficacy outcomes were more heterogeneous in animal studies than in clinical studies, which could be due to limited external validity of the animal models in terms of aneurysm induction and dimensions. Both animal and clinical studies were predominantly single-arm studies, and were at unclear risk of several types of bias.

CONCLUSIONS

The rabbit elastase aneurysm model was the only pre-clinical animal model used to assess WEB device performance. Safety outcomes were not evaluated in animal studies and could therefore not be compared to clinical outcomes. Efficacy outcomes were more heterogeneous in animal studies than in clinical studies. Future research should focus on improving methodology and reporting in order to draw accurate conclusions on the performance of the WEB device.

Systematic Evaluation of Spinal Cord Injury Animal Models in the Field of Biomaterials

The large number of animal models used in spinal cord injury (SCI) research complicates the objective selection of the most appropriate model to investigate the efficacy of biomaterial-based therapies. This systematic review aims to identify a list of relevant animal models of SCI by evaluating the confirmation of SCI and animal survival in all published SCI models used in biomaterials research up until April 2021. A search in PubMed and Embase based on "spinal cord injury," "animal models," and "biomaterials" yielded 4606 papers, 393 of which were further evaluated. A total of 404 individual animal experiments were identified based on type of SCI, level of SCI, and the sex, species, and strain of the animals used. Finally, a total of 149 unique animal models were comparatively evaluated, which led to the generation of an evidence-based list of well-documented mid-thoracic rat models of SCI. These models were used most often, clearly confirmed SCI, and had relatively high survival rates, and therefore could serve as a future starting point for studying novel biomaterial-based therapies for SCI. Furthermore, the review discusses (1) the possible risk of bias in SCI animal models, (2) the difficulty in replication of such experiments due to frequent poor reporting of the methods and results, and (3) the clinical relevance of the currently utilized models. Systematic review registration: The study was prospectively registered in PROSPERO, registration number CRD42019141162. Impact statement Studies on biomaterial-based therapies within the field of spinal cord injury (SCI) research show a large inconsistency concerning the selection of animal models. This review goes beyond summarizing the existing gaps between experimental and clinical SCI by systematically evaluating all animal models used within this field. The models identified by this work were used most often, clearly confirmed SCI, and had a relatively high survival rate. This evidence-based list of well-documented animal models will serve as a practical guideline in future research on innovative biomaterial-based therapies for SCI.

Assessment of key characteristics, methodology, and effect size measures used in meta-analysis of human-health-related animal studies

Since the early 1990s the number of systematic reviews (SR) of animal studies has steadily increased. There is, however, little guidance on when and how to conduct a meta-analysis of human-health-related animal studies. To gain insight about the methods that are currently used we created an overview of the key characteristics of published meta-analyses of animal studies, with a focus on the choice of effect size measures. An additional goal was to learn about the rationale behind the meta-analysis methods used by the review authors. We show that important details of the meta-analyses are not fully described, only a fraction of all human-health-related meta-analyses provided rationales for their decision to use specific effect size measures. In addition, our data may suggest that authors make post-hoc decisions to switch to another effect size measure during the course of their meta-analysis, and possibly search for significant effects. Based on analyses in this paper we recommend that review teams: 1) publish a review protocol before starting the conduct of a SR, prespecifying all methodological details (providing special attention to the planned meta-analysis including the effect size measure and the rational behind choosing a specific effect size, prespecifying subgroups and restricting the number of subgroup analyses), 2) always use the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) checklist to report your SR of animal studies, and 3) use the random effects model (REM) in human-health-related meta-analysis of animal studies, unless the assumptions for using the fixed effect model (FEM) are all met.

Towards a reporting guideline for developmental and reproductive toxicology testing in C. elegans and other nematodes

Implementation of reliable methodologies allowing Reduction, Refinement, and Replacement (3Rs) of animal testing is a process that takes several decades and is still not complete. Reliable methods are essential for regulatory hazard assessment of chemicals where differences in test protocol can influence the test outcomes and thus affect the confidence in the predictive value of the organisms used as an alternative for mammals. Although test guidelines are common for mammalian studies, they are scarce for non-vertebrate organisms that would allow for the 3Rs of animal testing. Here, we present a set of 30 reporting criteria as the basis for such a guideline for Developmental and Reproductive Toxicology (DART) testing in the nematode Caenorhabditis elegans. Small organisms like C. elegans are upcoming in new approach methodologies for hazard assessment; thus, reliable and robust test protocols are urgently needed. A literature assessment of the fulfilment of the reporting criteria demonstrates that although studies describe methodological details, essential information such as compound purity and lot/batch number or type of container is often not reported. The formulated set of reporting criteria for C. elegans testing can be used by (i) researchers to describe essential experimental details (ii) data scientists that aggregate information to assess data quality and include data in aggregated databases (iii) regulators to assess study data for inclusion in regulatory hazard assessment of chemicals.

A 3-year evaluation of preclinicaltrials.eu reveals room for improvement in preregistration of animal studies

In 2018, the first registry dedicated to preregistration of animal study protocols was launched. Despite international support, the overall number of (pre)registered protocols is still low, illustrating the need for pushing the preregistration agenda among researchers and policymakers.

Introduction to the EQIPD quality system

While high risk of failure is an inherent part of developing innovative therapies, it can be reduced by adherence to evidence-based rigorous research practices. Supported through the European Union's Innovative Medicines Initiative, the EQIPD consortium has developed a novel preclinical research quality system that can be applied in both public and private sectors and is free for anyone to use. The EQIPD Quality System was designed to be suited to boost innovation by ensuring the generation of robust and reliable preclinical data while being lean, effective and not becoming a burden that could negatively impact the freedom to explore scientific questions. EQIPD defines research quality as the extent to which research data are fit for their intended use. Fitness, in this context, is defined by the stakeholders, who are the scientists directly involved in the research, but also their funders, sponsors, publishers, research tool manufacturers, and collaboration partners such as peers in a multi-site research project. The essence of the EQIPD Quality System is the set of 18 core requirements that can be addressed flexibly, according to user-specific needs and following a user-defined trajectory. The EQIPD Quality System proposes guidance on expectations for quality-related measures, defines criteria for adequate processes (i.e. performance standards) and provides examples of how such measures can be developed and implemented. However, it does not prescribe any pre-determined solutions. EQIPD has also developed tools (for optional use) to support users in implementing the system and assessment services for those research units that successfully implement the quality system and seek formal accreditation. Building upon the feedback from users and continuous improvement, a sustainable EQIPD Quality System will ultimately serve the entire community of scientists conducting non-regulated preclinical research, by helping them generate reliable data that are fit for their intended use.

Epidemiology and reporting characteristics of preclinical systematic reviews

In an effort to better utilize published evidence obtained from animal experiments, systematic reviews of preclinical studies are increasingly more common-along with the methods and tools to appraise them (e.g., SYstematic Review Center for Laboratory animal Experimentation [SYRCLE's] risk of bias tool). We performed a cross-sectional study of a sample of recent preclinical systematic reviews (2015-2018) and examined a range of epidemiological characteristics and used a 46-item checklist to assess reporting details. We identified 442 reviews published across 43 countries in 23 different disease domains that used 26 animal species. Reporting of key details to ensure transparency and reproducibility was inconsistent across reviews and within article sections. Items were most completely reported in the title, introduction, and results sections of the reviews, while least reported in the methods and discussion sections. Less than half of reviews reported that a risk of bias assessment for internal and external validity was undertaken, and none reported methods for evaluating construct validity. Our results demonstrate that a considerable number of preclinical systematic reviews investigating diverse topics have been conducted; however, their quality of reporting is inconsistent. Our study provides the justification and evidence to inform the development of guidelines for conducting and reporting preclinical systematic reviews.

Publication rate in preclinical research: a plea for preregistration

OBJECTIVES

The ultimate goal of biomedical research is the development of new treatment options for patients. Animal models are used if questions cannot be addressed otherwise. Currently, it is widely believed that a large fraction of performed studies are never published, but there are no data that directly address this question.

METHODS

We have tracked a selection of animal study protocols approved in the University Medical Center Utrecht in the Netherlands, to assess whether these have led to a publication with a follow-up period of 7 years.

RESULTS

We found that 60% of all animal study protocols led to at least one publication (full text or abstract). A total of 5590 animals were used in these studies, of which 26% was reported in the resulting publications.

CONCLUSIONS

The data presented here underline the need for preclinical preregistration, in view of the risk of reporting and publication bias in preclinical research. We plea that all animal study protocols should be prospectively registered on an online, accessible platform to increase transparency and data sharing. To facilitate this, we have developed a platform dedicated to animal study protocol registration: www.preclinicaltrials.eu.

The transverse aortic constriction heart failure animal model: a systematic review and meta-analysis

The transverse aortic constriction (TAC) model is frequently used to study adverse cardiac remodeling upon pressure overload. We set out to define the most important characteristics that define the degree of cardiac remodeling in this model. A systematic review and meta-analyses were performed on studies using the TAC mouse/rat model and reporting echocardiographic outcome parameters. We included all animal studies in which a constriction around the transverse aorta and at least one of the predefined echocardiography or MRI outcome parameters were assessed. A total of 502 articles and > 3000 wild-type, untreated animals undergoing TAC were included in this study and referenced to a control group. The duration of aortic constriction correlated to the degree of adverse remodeling. However, the mouse data is strongly biased by the preferential use of male C57Bl/6 mice (66% of studies). Furthermore, mostly ketamine/xylazine anesthetics, 27G needle constriction, and silk sutures are used. Nonetheless, despite the homogeneity in experimental design, the model contained a substantial degree of heterogeneity in the functional outcome measures. When looking at study quality, only 12% reported randomization, 23% mentioned any sort of blinding, 25% adequately addressed the outcomes, and an amazingly low percentage (2%) showed sample size calculation. Meta-analyses did not detect specific study characteristics that explained the heterogeneity in the reported outcome measures, however this might be related to the strong bias towards the use of specific mouse lines, sex as well as age or to poor reporting of characteristics of study quality.

A Systematic Review on Transplantation Studies of the Retinal Pigment Epithelium in Animal Models

The retinal pigment epithelium (RPE) and the adjacent light-sensitive photoreceptors form a single functional unit lining the back of the eye. Both cell layers are essential for normal vision. RPE degeneration is usually followed by photoreceptor degeneration and vice versa. There are currently almost no effective therapies available for RPE disorders such as Stargardt disease, specific types of retinitis pigmentosa, and age-related macular degeneration. RPE replacement for these disorders, especially in later stages of the disease, may be one of the most promising future therapies. There is, however, no consensus regarding the optimal RPE source, delivery strategy, or the optimal experimental host in which to test RPE replacement therapy. Multiple RPE sources, delivery methods, and recipient animal models have been investigated, with variable results. So far, a systematic evaluation of the (variables influencing) efficacy of experimental RPE replacement parameters is lacking. Here we investigate the effect of RPE transplantation on vision and vision-based behavior in animal models of retinal degenerated diseases. In addition, we aim to explore the effect of RPE source used for transplantation, the method of intervention, and the animal model which is used.

METHODS

In this study, we systematically identified all publications concerning transplantation of RPE in experimental animal models targeting the improvement of vision (e.g., outcome measurements related to the morphology or function of the eye). A variety of characteristics, such as species, gender, and age of the animals but also cell type, number of cells, and other intervention characteristics were extracted from all studies. A risk of bias analysis was performed as well. Subsequently, all references describing one of the following outcomes were analyzed in depth in this systematic review: a-, b-, and c-wave amplitudes, vision-based, thickness analyses based on optical coherence tomography (OCT) data, and transplant survival based on scanning laser ophthalmoscopy (SLO) data. Meta-analyses were performed on the a- and b-wave amplitudes from electroretinography (ERG) data as well as data from vision-based behavioral assays.

RESULTS

original research articles met the inclusion criteria after two screening rounds. Overall, most studies were categorized as unclear regarding the risk of bias, because many experimental details were poorly reported. Twenty-three studies reporting one or more of the outcome measures of interest were eligible for either descriptive (thickness analyses based on OCT data; n = 2) or meta-analyses. RPE transplantation significantly increased ERG a-wave (Hedges' g 1.181 (0.471-1.892), n = 6) and b-wave (Hedges' g 1.734 (1.295-2.172), n = 42) amplitudes and improved vision-based behavior (Hedges' g 1.018 (0.826-1.209), n = 96). Subgroup analyses revealed a significantly increased effect of the use of young and adolescent animals compared to adult animals. Moreover, transplanting more cells (in the range of 105 versus in the range of 104) resulted in a significantly increased effect on vision-based behavior as well. The origin of cells mattered as well. A significantly increased effect was found on vision-based behavior when using ARPE-19 and OpRegen® RPE.

CONCLUSIONS

This systematic review shows that RPE transplantation in animal models for retinal degeneration significantly increases a- and b- wave amplitudes and improves vision-related behavior. These effects appear to be more pronounced in young animals, when the number of transplanted cells is larger and when ARPE-19 and OpRegen® RPE cells are used. We further emphasize that there is an urgent need for improving the reporting and methodological quality of animal experiments, to make such studies more comparable.

Conflicting Effects of Fetal Growth Restriction on Blood Pressure Between Human and Rat Offspring: A Meta-Analysis

Low birth weight is associated with hypertension. Low birth weight can result from fetal growth restriction (FGR) or prematurity. FGR is postulated to impact blood pressure (BP) by developmental programming. This systematic review and meta-analysis studies BP in human and animal offspring following FGR. Pubmed and Web of Science were searched for studies reporting on BP after placental insufficiency induced FGR compared with normal growth controls. Primary outcome was mean absolute BP difference (ΔBP mm Hg [95% CI]). Meta-analysis was performed using random-effects models. Subgroup analyses were executed on species, sex, age, pregnancy duration, and stress during BP readings. Due to large interspecies heterogeneity, analyses were performed separately for human (n=41) and animal (n=31) studies, the latter restricted to rats (n=27). Human studies showed a ΔBP between FGR and controls of -0.6 mm Hg ([95% CI, -1.7 to 0.6]; I²=91%). Mean ΔBP was -2.6 mm Hg (95% CI, -5.7 to 0.4) in women versus -0.5 mm Hg (95% CI, -3.7 to 2.7) in men. Subgroup analyses did not indicate age, gestational age, and stress during measurements as sources of heterogeneity. In rats, mean BP was 12.0 mm Hg ([95% CI, 8.8-15.2]; I²=81%) higher in FGR offspring. This difference was more pronounced in FGR males (13.6 mm Hg [95% CI, 10.3-17.0] versus 9.1 mm Hg [95% CI, 5.3-12.8]). Subgroup analyses on age showed no statistical interaction. BP readings under restrained conditions resulted in larger BP differences between FGR and control rats (15.3 mm Hg [95% CI, 11.6-18.9] versus 5.7 mm Hg [95% CI, 1.1-10.3]). Rat studies confirm the relation between FGR and offspring BP, while observational studies in humans do not show such differences. This may be due to the observational nature of human studies, methodological limitations, or an absence of this phenomenon in humans. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: CRD42018091819.

The protective effect of anterior cruciate ligament reconstruction on articular cartilage: a systematic review of animal studies

OBJECTIVE

It is unclear if anterior cruciate ligament (ACL) reconstruction can prevent the onset of degenerative changes in the knee. Previous studies were inconclusive on this subject. The aim of this study was to systematically review all studies on the effect of ACL reconstruction on articular cartilage in animals.

DESIGN

Pubmed and Embase were searched to identify all original articles concerning the effect of ACL reconstruction on articular cartilage compared with both its positive (ACL transection) and negative (sham and/or non-operated) control in animals. Subsequently a Risk of bias and meta analysis was conducted based on five outcomes (gross macroscopic assessment, medical imaging, histological histochemical grading, histomophometrics and biomechanical characterization) related to articular cartilage.

RESULTS

From the 19 included studies, 29 independent comparisons could be identified which underwent ACL reconstruction with an average timing of data collection of 23 weeks (range 1-104 weeks). Due to limited data availability meta-analysis could only be conducted for gross macroscopic damage. ACL reconstruction caused significant gross macroscopic damage compared with intact controls (SMD 2.0 [0.88; 3.13]). These findings were supported by individual studies reporting on histomorphometrics, histology and imaging. No significant gross macroscopic damage was found when ACL reconstruction was compared with ACL transection (SMD -0.64 [-1.85; 0.57]).

CONCLUSION

This systematic review with an average follow up of included studies of 23 weeks (range 1-104 weeks) demonstrates that, in animals, ACL reconstruction does not protect articular cartilage from degenerative changes. The consistency of the direction of effect, provides some reassurance that the direction of effect in humans might be the same.

Protocol for a systematic review of guidelines for rigour in the design, conduct and analysis of biomedical experiments involving laboratory animals

Objective

Within the last years, there has been growing awareness of the negative repercussions of unstandardized planning, conduct and reporting of preclinical and biomedical research. Several initiatives have set the aim of increasing validity and reliability in reporting of studies and publications, and publishers have formed similar groups. Additionally, several groups of experts across the biomedical spectrum have published experience and opinion-based guidelines and guidance on potential standardized reporting. While all these guidelines cover reporting of experiments, an important step prior to this should be rigours planning and conduction of studies. The aim of this systematic review is to identify and harmonize existing experimental design, conduct and analysis guidelines relating to internal validity and reproducibility of preclinical animal research. The review will also identify literature describing risks of bias pertaining to the design, conduct and analysis of preclinical biomedical research.

Search strategy

PubMed, Embase and Web of Science will be searched systematically to identify guidelines published in English language in peer-reviewed journals before January 2018 (box 1). All articles or systematic reviews in English language that describe or review guidelines on the internal validity and reproducibility of animal studies will be included. Google search for guidelines published on the websites of major funders and professional organisations can be found in (Box 2).

Screening and annotation

Unique references will be screened in two phases: screening for eligibility based on title and abstract, followed by screening for definitive inclusion based on full text. Screening will be performed in SyRF (http://syrf.org.uk). Each reference will be randomly presented to two independent reviewers. Disagreements between reviewers will be resolved by additional screening of the reference by a third, senior researcher.

Data management and reporting

All data, including extracted text and guidelines, will be stored in the SyRF platform. Elements of the included guidelines will be identified using a standardized extraction form. Reporting will follow the PRISMA guidelines as far as applicable.

Effects of hyperoxia on vascular tone in animal models: systematic review and meta-analysis

BACKGROUND

Arterial hyperoxia may induce vasoconstriction and reduce cardiac output, which is particularly undesirable in patients who already have compromised perfusion of vital organs. Due to the inaccessibility of vital organs in humans, vasoconstrictive effects of hyperoxia have primarily been studied in animal models. However, the results of these studies vary substantially. Here, we investigate the variation in magnitude of the hyperoxia effect among studies and explore possible sources of heterogeneity, such as vascular region and animal species.

METHOD

Pubmed and Embase were searched for eligible studies up to November 2017. In vivo and ex vivo animal studies reporting on vascular tone changes induced by local or systemic normobaric hyperoxia were included. Experiments with co-interventions (e.g. disease or endothelium removal) or studies focusing on lung, brain or fetal vasculature or the ductus arteriosus were not included. We extracted data pertaining to species, vascular region, blood vessel characteristics and method of hyperoxia induction. Overall effect sizes were estimated with a standardized mean difference (SMD) random effects model.

RESULTS

We identified a total of 60 studies, which reported data on 67 in vivo and 18 ex vivo experiments. In the in vivo studies, hyperoxia caused vasoconstriction with an SMD of - 1.42 (95% CI - 1.65 to - 1.19). Ex vivo, the overall effect size was SMD - 0.56 (95% CI - 1.09 to - 0.03). Between-study heterogeneity (I2) was high for in vivo (72%, 95% CI 62 to 85%) and ex vivo studies (86%, 95% CI 78 to 98%). In vivo, in comparison to the overall effect size, hyperoxic vasoconstriction was less pronounced in the intestines and skin (P = 0.03) but enhanced in the cremaster muscle region (P < 0.001). Increased constriction was seen in vessels 15-25 μm in diameter. Hyperoxic constriction appeared to be directly proportional to oxygen concentration. For ex vivo studies, heterogeneity could not be explained with subgroup analysis.

CONCLUSION

The effect of hyperoxia on vascular tone is substantially higher in vivo than ex vivo. The magnitude of the constriction is most pronounced in vessels ~ 15-25 μm in diameter and is proportional to the level of hyperoxia. Relatively increased constriction was seen in muscle vasculature, while reduced constriction was seen in the skin and intestines.

Facilitating healthcare decisions by assessing the certainty in the evidence from preclinical animal studies

Laboratory animal studies are used in a wide range of human health related research areas, such as basic biomedical research, drug research, experimental surgery and environmental health. The results of these studies can be used to inform decisions regarding clinical research in humans, for example the decision to proceed to clinical trials. If the research question relates to potential harms with no expectation of benefit (e.g., toxicology), studies in experimental animals may provide the only relevant or controlled data and directly inform clinical management decisions. Systematic reviews and meta-analyses are important tools to provide robust and informative evidence summaries of these animal studies. Rating how certain we are about the evidence could provide important information about the translational probability of findings in experimental animal studies to clinical practice and probably improve it. Evidence summaries and certainty in the evidence ratings could also be used (1) to support selection of interventions with best therapeutic potential to be tested in clinical trials, (2) to justify a regulatory decision limiting human exposure (to drug or toxin), or to (3) support decisions on the utility of further animal experiments. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach is the most widely used framework to rate the certainty in the evidence and strength of health care recommendations. Here we present how the GRADE approach could be used to rate the certainty in the evidence of preclinical animal studies in the context of therapeutic interventions. We also discuss the methodological challenges that we identified, and for which further work is needed. Examples are defining the importance of consistency within and across animal species and using GRADE's indirectness domain as a tool to predict translation from animal models to humans.

Standardized mean differences cause funnel plot distortion in publication bias assessments

Meta-analyses are increasingly used for synthesis of evidence from biomedical research, and often include an assessment of publication bias based on visual or analytical detection of asymmetry in funnel plots. We studied the influence of different normalisation approaches, sample size and intervention effects on funnel plot asymmetry, using empirical datasets and illustrative simulations. We found that funnel plots of the Standardized Mean Difference (SMD) plotted against the standard error (SE) are susceptible to distortion, leading to overestimation of the existence and extent of publication bias. Distortion was more severe when the primary studies had a small sample size and when an intervention effect was present. We show that using the Normalised Mean Difference measure as effect size (when possible), or plotting the SMD against a sample size-based precision estimate, are more reliable alternatives. We conclude that funnel plots using the SMD in combination with the SE are unsuitable for publication bias assessments and can lead to false-positive results.

A systematic review and meta-analysis of the protective effects of metformin in experimental myocardial infarction

Metformin improves cardiovascular prognosis in patients with diabetes mellitus, compared to alternative glucose-lowering drugs, despite similar glycemic control. Direct cardiovascular protective properties have therefore been proposed, and studied in preclinical models of myocardial infarction. We now aim to critically assess the quality and outcome of these studies. We present a systematic review, quality assessment and meta-analysis of the effect of metformin in animal studies of experimental myocardial infarction. Through a comprehensive search in Pubmed and EMBASE, we identified 27 studies, 11 reporting on ex vivo experiments and 18 reporting on in vivo experiments. The primary endpoint infarct size as percentage of area at risk was significantly reduced by metformin in vivo (MD -18.11[-24.09,-12.14]) and ex vivo (MD -18.70[-25.39, -12.02]). Metformin improved the secondary endpoints left ventricular ejection fraction (LVEF) and left ventricular end systolic diameter. A borderline significant effect on mortality was observed, and there was no overall effect on cardiac hypertrophy. Subgroup analyses could be performed for comorbidity and timing of treatment (infarct size and mortality) and species and duration of ischemia (LVEF), but none of these variables accounted for significant amounts of heterogeneity. Reporting of possible sources of bias was extremely poor, including randomization (reported in 63%), blinding (33%), and sample size calculation (0%). As a result, risk of bias (assessed using SYRCLE’s risk of bias tool) was unclear in the vast majority of studies. We conclude that metformin limits infarct-size and improves cardiac function in animal models of myocardial infarction, but our confidence in the evidence is lowered by the unclear risk of bias and residual unexplained heterogeneity. We recommend an adequately powered, high quality confirmatory animal study to precede a randomized controlled trial of acute administration of metformin in patients undergoing reperfusion for acute myocardial infarction.

A systematic review of discomfort due to toe or ear clipping in laboratory rodents

Toe clipping and ear clipping (also ear notching or ear punching) are frequently used methods for individual identification of laboratory rodents. These procedures potentially cause severe discomfort, which can reduce animal welfare and distort experimental results. However, no systematic summary of the evidence on this topic currently exists. We conducted a systematic review of the evidence for discomfort due to toe or ear clipping in rodents. The review methodology was pre-specified in a registered review protocol. The population, intervention, control, outcome (PICO) question was: In rodents, what is the effect of toe clipping or ear clipping, compared with no clipping or sham clipping, on welfare-related outcomes? Through a systematic search in PubMed, Embase, Web of Science and grey literature, we identified seven studies on the effect of ear clipping on animal welfare, and five such studies on toe clipping. Studies were included in the review if they contained original data from an in vivo experiment in rodents, assessing the effect of toe clipping or ear clipping on a welfare-related outcome. Case studies and studies applying unsuitable co-interventions were excluded. Study quality was appraised using an extended version of SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE)'s risk of bias tool for animal studies. Study characteristics and outcome measures were highly heterogeneous, and there was an unclear or high risk of bias in all studies. We therefore present a narrative synthesis of the evidence identified. None of the studies reported a sample size calculation. Out of over 60 different outcomes, we found evidence of discomfort due to ear clipping in the form of increased respiratory volume, vocalization and blood pressure. For toe clipping, increased vocalization and decreased motor activity in pups were found, as well as long-term effects in the form of reduced grip strength and swimming ability in adults. In conclusion, there is too little evidence to reliably assess discomfort due to toe or ear clipping, and the quality of the available evidence is uncertain. Adequately powered, high-quality studies reporting reliable, relevant outcome measures are needed to accurately assess the impact of these identification techniques. Until more reliable evidence is available, any effect of toe clipping or ear clipping on animal welfare and study results cannot be confirmed or excluded.

Ischaemic preconditioning for the reduction of renal ischaemia reperfusion injury

BACKGROUND

Ischaemia reperfusion injury can lead to kidney dysfunction or failure. Ischaemic preconditioning is a short period of deprivation of blood supply to particular organs or tissue, followed by a period of reperfusion. It has the potential to protect kidneys from ischaemia reperfusion injury.

OBJECTIVES

This review aimed to look at the benefits and harms of local and remote ischaemic preconditioning to reduce ischaemia and reperfusion injury among people with renal ischaemia reperfusion injury.

SEARCH METHODS

We searched Cochrane Kidney and Transplant's Specialised Register to 5 August 2016 through contact with the Information Specialist using search terms relevant to this review.

SELECTION CRITERIA

We included all randomised controlled trials measuring kidney function and the role of ischaemic preconditioning in patients undergoing a surgical intervention that induces kidney injury. Kidney transplantation studies were excluded.

DATA COLLECTION AND ANALYSIS

Studies were assessed for eligibility and quality; data were extracted by two independent authors. We collected basic study characteristics: type of surgery, remote ischaemic preconditioning protocol, type of anaesthesia. We collected primary outcome measurements: serum creatinine and adverse effects to remote ischaemic preconditioning and secondary outcome measurements: acute kidney injury, need for dialysis, neutrophil gelatinase-associated lipocalin, hospital stay and mortality. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

We included 28 studies which randomised a total of 6851 patients. Risk of bias assessment indicated unclear to low risk of bias for most studies. For consistency regarding the direction of effects, continuous outcomes with negative values, and dichotomous outcomes with values less than one favour remote ischaemic preconditioning. Based on high quality evidence, remote ischaemic preconditioning made little or no difference to the reduction of serum creatinine levels at postoperative days one (14 studies, 1022 participants: MD -0.02 mg/dL, 95% CI -0.05 to 0.02; I2 = 21%), two (9 studies, 770 participants: MD -0.04 mg/dL, 95% CI -0.09 to 0.02; I2 = 31%), and three (6 studies, 417 participants: MD -0.05 mg/dL, 95% CI -0.19 to 0.10; I2 = 68%) compared to control.Serious adverse events occurred in four patients receiving remote ischaemic preconditioning by iliac clamping. It is uncertain whether remote ischaemic preconditioning by cuff inflation leads to increased adverse effects compared to control because the certainty of the evidence is low (15 studies, 3993 participants: RR 3.47, 95% CI 0.55 to 21.76; I2 = 0%); only two of 15 studies reported any adverse effects (6/1999 in the remote ischaemic preconditioning group and 1/1994 in the control group), the remaining 13 studies stated no adverse effects were observed in either group.Compared to control, remote ischaemic preconditioning made little or no difference to the need for dialysis (13 studies, 2417 participants: RR 0.85, 95% CI 0.37 to 1.94; I2 = 60%; moderate quality evidence), length of hospital stay (8 studies, 920 participants: MD 0.17 days, 95% CI -0.46 to 0.80; I2 = 49%, high quality evidence), or all-cause mortality (24 studies, 4931 participants: RR 0.86, 95% CI 0.54 to 1.37; I2 = 0%, high quality evidence).Remote ischaemic preconditioning may have slightly improved the incidence of acute kidney injury using either the AKIN (8 studies, 2364 participants: RR 0.76, 95% CI 0.57 to 1.00; I2 = 61%, high quality evidence) or RIFLE criteria (3 studies, 1586 participants: RR 0.91, 95% CI 0.75 to 1.12; I2 = 0%, moderate quality evidence).

AUTHORS' CONCLUSIONS

Remote ischaemic preconditioning by cuff inflation appears to be a safe method, and probably leads to little or no difference in serum creatinine, adverse effects, need for dialysis, length of hospital stay, death and in the incidence of acute kidney injury. Overall we had moderate-high certainty evidence however the available data does not confirm the efficacy of remote ischaemic preconditioning in reducing renal ischaemia reperfusion injury in patients undergoing major cardiac and vascular surgery in which renal ischaemia reperfusion injury may occur.

Renal Perfusion and Function during Pneumoperitoneum: A Systematic Review and Meta-Analysis of Animal Studies

Both preclinical and clinical studies indicate that raised intra-abdominal pressure (IAP) associated with pneumoperitoneum during laparoscopic surgical procedures can cause renal damage, the severity of which may be influenced by variables such as pressure level and duration. Several of these variables have been investigated in animal studies, but synthesis of all preclinical data has not been performed. This systematic review summarizes all available pre-clinical evidence on this topic, including an assessment of its quality and risk of bias. We performed meta-analysis to assess which aspects of the pneumoperitoneum determine the severity of its adverse effects. A systematic search in two databases identified 55 studies on the effect of pneumoperitoneum on renal function which met our inclusion criteria. There was high heterogeneity between the studies regarding study design, species, sex, pressure and duration of pneumoperitoneum, and type of gas used. Measures to reduce bias were poorly reported, leading to an unclear risk of bias in the majority of studies. Details on randomisation, blinding and a sample size calculation were not reported in ≥80% of the studies. Meta-analysis showed an overall increase in serum creatinine during pneumoperitoneum, and a decrease in urine output and renal blood flow. Subgroup analysis indicated that for serum creatinine, this effect differed between species. Subgroup analysis of pressure level indicated that urine output decreased as IAP level increased. No differences between types of gas were observed. Data were insufficient to reliably assess whether sex or IAP duration modulate the effect of pneumoperitoneum. Four studies assessing long-term effects indicated that serum creatinine normalized ≥24 hours after desufflation of pneumoperitoneum at 15mmHg. We conclude that harmful effects on renal function and perfusion during pneumoperitoneum appear to be robust, but evidence on long-term effects is very limited. The reliability and clinical relevance of these findings for healthy patients and patients at high risk of renal impairment remain uncertain. We emphasize the need for rigorous reporting of preclinical research methodology, which is of vital importance for clinical translation of preclinical data.

Preclinical Evidence for the Efficacy of Ischemic Postconditioning against Renal Ischemia-Reperfusion Injury, a Systematic Review and Meta-Analysis

BACKGROUND

Renal ischemia-reperfusion injury (IRI) is a major cause of kidney damage after e.g. renal surgery and transplantation. Ischemic postconditioning (IPoC) is a promising treatment strategy for renal IRI, but early clinical trials have not yet replicated the promising results found in animal studies.

METHOD

We present a systematic review, quality assessment and meta-analysis of the preclinical evidence for renal IPoC, and identify factors which modify its efficacy.

RESULTS

We identified 39 publications studying >250 control animals undergoing renal IRI only and >290 animals undergoing renal IRI and IPoC. Healthy, male rats undergoing warm ischemia were used in the vast majority of studies. Four studies applied remote IPoC, all others used local IPoC. Meta-analysis showed that both local and remote IPoC ameliorated renal damage after IRI for the outcome measures serum creatinine, blood urea nitrogen and renal histology. Subgroup analysis indicated that IPoC efficacy increased with the duration of index ischemia. Measures to reduce bias were insufficiently reported.

CONCLUSION

High efficacy of IPoC is observed in animal models, but factors pertaining to the internal and external validity of these studies may hamper the translation of IPoC to the clinical setting. The external validity of future animal studies should be increased by including females, comorbid animals, and transplantation models, in order to better inform clinical trial design. The severity of renal damage should be taken into account in the design and analysis of future clinical trials.

The usefulness of systematic reviews of animal experiments for the design of preclinical and clinical studies

The question of how animal studies should be designed, conducted, and analyzed remains underexposed in societal debates on animal experimentation. This is not only a scientific but also a moral question. After all, if animal experiments are not appropriately designed, conducted, and analyzed, the results produced are unlikely to be reliable and the animals have in effect been wasted. In this article, we focus on one particular method to address this moral question, namely systematic reviews of previously performed animal experiments. We discuss how the design, conduct, and analysis of future (animal and human) experiments may be optimized through such systematic reviews. In particular, we illustrate how these reviews can help improve the methodological quality of animal experiments, make the choice of an animal model and the translation of animal data to the clinic more evidence-based, and implement the 3Rs. Moreover, we discuss which measures are being taken and which need to be taken in the future to ensure that systematic reviews will actually contribute to optimizing experimental design and thereby to meeting a necessary condition for making the use of animals in these experiments justified.

Systematic review of experimental studies on intestinal anastomosis

BACKGROUND

The contribution of animal research to a reduction in clinical intestinal anastomotic leakage is unknown, despite numerous experimental studies. In view of the current societal call to replace, reduce and refine animal experiments, this study examined the quality of animal research related to anastomotic healing and leakage.

METHODS

Animal studies on intestinal anastomotic healing were retrieved systematically from PubMed and Embase. Study objective, conclusion and animal model were recorded. Reporting quality and internal validity (reporting of randomization and blinding) were assessed.

RESULTS

A total of 1342 studies were identified, with a rising publication rate. The objectives of most studies were therapeutic interventions (64·8 per cent) and identification of risk factors (27·5 per cent). Of 350 articles studying experimental therapies, 298 (85·1 per cent) reported a positive effect on anastomotic healing. On average, 44·7 per cent of relevant study characteristics were not reported, in particular details on anastomotic complications (31·6 per cent), use of antibiotics (75·7 per cent), sterile surgery (83·4 per cent) and postoperative analgesia (91·4 per cent). The proportion of studies with randomization, blinding of surgery and blinding of primary outcome assessment has increased in the past two decades but remains insufficient, being included in only 62·4, 4·9 and 8·5 per cent of publications respectively. Animal models varied widely in terms of species, method to compromise healing, intestinal segment and outcome measures used.

CONCLUSION

Animal research on anastomotic leakage is of poor quality and still increasing, contrary to societal aims. Reporting and study quality must improve if results are to impact on patients.

Cardiovascular pharmacotherapy: Innovation stuck in translation

Systematic reviews of animal studies have revealed serious limitations in internal and external validity strongly affecting the reliability of this research. In addition inter-species differences are likely to further limit the predictive value of animal research for the efficacy and tolerability of new drugs in humans. Important changes in the research process are needed to allow efficient translation of preclinical discoveries to the clinic, including improvements in the laboratory and publication practices involving animal research and early incorporation of human proof-of-concept studies to optimize the interpretation of animal data for its predictive value for humans and the design of clinical trials.

Remote ischemic preconditioning to reduce contrast-induced nephropathy: study protocol for a randomized controlled trial

Background

Despite the increasing use of pre- and posthydration protocols and low-osmolar instead of high-osmolar iodine-containing contrast media, the incidence of contrast-induced nephropathy (CIN) is still significant. There is evidence that contrast media cause ischemia-reperfusion injury of the medulla. Remote ischemic preconditioning (RIPC) is a non-invasive, safe, and low-cost method to reduce ischemia-reperfusion injury.

Methods

The RIPCIN study is a multicenter, single-blinded, randomized controlled trial in which 76 patients at risk of CIN will receive standard hydration combined with RIPC or hydration with sham preconditioning. RIPC will be applied by four cycles of 5 min ischemia and 5 min reperfusion of the forearm by inflating a blood pressure cuff at 50 mmHg above the actual systolic pressure. The primary outcome measure will be the change in serum creatinine from baseline to 48 to 72 h after contrast administration.

Discussion

A recent pilot study reported that RIPC reduced the incidence of CIN after coronary angioplasty. The unusual high incidence of CIN in this study is of concern and limits its generalizability. Therefore, we propose a randomized controlled trial to study whether RIPC reduces contrast-induced kidney injury in patients at risk for CIN according to the Dutch guidelines.

Trial registration

Current Controlled Trials ISRCTN76496973

Low-pressure pneumoperitoneum during laparoscopic donor nephrectomy to optimize live donors' comfort

Nowadays, laparoscopic donor nephrectomy (LDN) has become the gold standard to procure live donor kidneys. As the relationship between donor and recipient loosens, it becomes of even greater importance to optimize safety and comfort of the surgical procedure. Low-pressure pneumoperitoneum has been shown to reduce pain scores after laparoscopic cholecystectomy. Live kidney donors may also benefit from the use of low pressure during LDN. To evaluate feasibility and efficacy to reduce post-operative pain, we performed a randomized blinded study. Twenty donors were randomly assigned to standard (14 mmHg) or low (7 mmHg) pressure during LDN. One conversion from low to standard pressure was indicated by protocol due to lack of progression. Intention-to-treat analysis showed that low pressure resulted in a significantly longer skin-to-skin time (149 ± 86 vs. 111 ± 19 min), higher urine output during pneumoperitoneum (23 ± 35 vs. 11 ± 20 mL/h), lower cumulative overall pain score after 72 h (9.4 ± 3.2 vs. 13.5 ± 4.5), lower deep intra-abdominal pain score (11 ± 3.3 vs. 7.5 ± 3.1), and a lower cumulative overall referred pain score (1.8 ± 1.9 vs. 4.2 ± 3). Donor serum creatinine levels, complications, and quality of life dimensions were not significantly different. Our data show that low-pressure pneumoperitoneum during LDN is feasible and may contribute to increase live donors' comfort during the early post-operative phase.

Rapid, nongenomic stimulation of multidrug resistance protein 2 (Mrp2) activity by glucocorticoids in renal proximal tubule

In renal proximal tubule, multidrug resistance protein 2 (Mrp2) actively transports many organic anions into urine, including drugs and metabolic wastes. Upon exposure to nephrotoxicants or during endotoxemia, both Mrp2 activity and expression are up-regulated. This may result from induced de novo synthesis of Mrp2 or post-transcriptional events involving specific signaling pathways. Here, we investigated glucocorticoid signaling to Mrp2 in killifish renal proximal tubules, a model system in which transport activity can be measured using a fluorescent substrate and confocal imaging. Exposure of tubules to dexamethasone rapidly increased Mrp2-mediated fluorescein methotrexate transport. Other glucocorticoid receptor (GR) ligands, cortisol and triamcinolone acetonide, also stimulated Mrp2-mediated transport. The GR antagonist, mifepristone 17β-hydroxy-11β-[4-dimethylamino phenyl]-17α-[1-propynyl]estra-4,9-dien-3-one (RU486), abolished stimulation by all three ligands, whereas the mineralocorticoid receptor antagonist, spironolactone, was ineffective. Consistent with action through a nongenomic mechanism, dexamethasone stimulation of Mrp2-mediated transport was insensitive to cycloheximide and actinomycin D, and immunohistochemistry revealed no alterations in Mrp2 expression at the luminal membrane. (9S-(9α,10β,12α))-2,3,9,10,11,12-hexahydro-10-hydroxy-10-(methoxycarbonyl)-9-methyl-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i][1,6]benzodiazocin-1-one (K252a), an inhibitor of the tyrosine receptor kinase subfamily, reduced the dexamethasone effect, as did the specific hepatocyte growth factor receptor (c-Met) tyrosine kinase inhibitor, (2R)-1-[[5-[(Z)-[5-[[(2,6-dichlorophenyl)methyl]sulfonyl]-1,2-dihydro-2-oxo-3H-indol-3-ylidene]methyl]-2,4-dimethyl-1H-pyrrol-3-yl]carbonyl]-2-(1-pyrrolidinylmethyl)pyrrolidine (PHA-665752). Hepatocyte growth factor (HGF), an endogenous ligand for c-Met, stimulated Mrp2-mediated transport. This effect was reversed by PHA-665752 but not by RU486. Inhibition of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK 1/2) also abolished the effects of dexamethasone and HGF. Our results disclose a novel mechanism by which glucocorticoids acting through GR, c-Met, and MEK1/2 cause rapid, nongenomic stimulation of Mrp2-mediated transport in renal proximal tubules. This up-regulation may be nephroprotective, enhancing efflux of metabolic wastes and toxicants during cell and tissue stress.