Biology subjects

Talbot, S. R.

Publications and source records attributed to Talbot, S. R..

6 recordsLinked to original sources

bioRxiv2024

T-cell development and activation in humanized mice lacking mouse major histocompatibility complexes

Humanized mice transplanted with CD34+ hematopoietic progenitor cells (HPCs) are used to study human immune responses in vivo. However, the mismatch between the mouse major histocompatibility complexes (MHCs) and the human leukocyte antigens (HLAs) is not optimal for T-cell development and can trigger xenograft reactivity. We evaluated human T-cell development in NOD.Scid.Gamma mice lacking expression of MHC class I and II (NSG-DKO). Human leukocyte engraftment was detectable at 8 weeks post-transplantation. Human CD4+ and CD8+ T-cells were detectable in blood, thymus, bone marrow and spleen of humanized NSG-DKO mice for up to 20 weeks post-transplantation. Further, we evaluated the effects of lentiviral vector (LV) systemic delivery of HLA-A*02:01, HLA-DRB1*04:01, human GM-CSF/IFN- and the human cytomegalovirus gB antigen. LV delivery promoted development and activation of human central memory, {beta} and {gamma}{delta} T-cells with amplifications of the T-cell repertoire. LV administration unleashed multiple reactome pathways such as type-I interferon responses, cell cycle and metabolic processes. In summary, development of human T-cells in humanized mice does not rely on mouse MHCs and can be boosted systemically via LV administration.

immunology↗

bioRxiv2024

A Systematic Assessment of Robustness in CNS Safety Pharmacology

Irwin tests are key preclinical study elements for characterizing drug-induced neurological side effects. This multicenter study aimed to assess the robustness of Irwin tests across multinational sites during three stages of protocol harmonization. The projects were part of the EQIPD framework (Enhanced Quality in Preclinical Data, https://quality-preclinical-data.eu/), aiming to increase success rates in transition from preclinical testing to clinical application. Female and male NMRI mice were assigned to one of three groups (vehicle, 0.1 mg/kg MK-801, 0.3 mg/kg MK-801). Irwin scores were assessed at baseline and multiple times following injection of MK-801, a non-competitive NMDA antagonist, using local protocols (stage 1), a shared protocol with harmonized environmental design (stage 2), and fully harmonized Irwin scoring protocols (stage 3). The analysis based on the four functional domains (motor, autonomic, sedation, and excitation) revealed substantial data variability in stages 1 and 2. Although there was still marked overall heterogeneity between sites in stage 3 after complete harmonization of the Irwin scoring scheme, heterogeneity was only moderate within functional domains. When comparing treatment groups vs. vehicle, we found large effect sizes in the motor domain and subtle to moderate effects in the excitation-related and autonomic domain. The pronounced interlaboratory variability in Irwin datasets for the CNS-active compound MK-801 needs to be carefully considered by companies and experimenters when making decisions during drug development. While environmental and general study design had a minor impact, the study suggests that harmonization of parameters and their scoring can limit variability and increase robustness.

neuroscience↗

bioRxiv2022

Robustness of a multivariate composite score when evaluating distress of animal models for gastrointestinal diseases

The fundament of an evidence-based severity assessment in laboratory animal science is reliable distress parameters. Many readouts are used to evaluate and determine animal distress and the severity of experimental procedures. Therefore, we analyzed four distinct parameters like the body weight, burrowing behavior, nesting, and distress score in the four gastrointestinal animal models (pancreatic ductal adenocarcinoma (PDA), pancreatitis, CCl4 intoxication, and bile duct ligation (BDL)). Further, we determined the parameters robustness in various experimental subgroups due to slight variations like drug treatment or telemeter implantations. We used non-parametric bootstrapping to get robust estimates and 95 % confidence intervals for the experimental groups. It was found that the performance of the readout parameters is model-dependent and that the distress score is prone to experimental variation. On the other hand, we also found that burrowing and nesting can be more robust than, e.g., the body weight when evaluating PDA. However, the body weight still was highly robust in BDL, pancreatitis, and CCl4 intoxication. To address the complex nature of the multi-dimensional severity space, we used the Relative Severity Assessment (RELSA) procedure to combine multiple distress parameters into a score and mapped the subgroups and models against a defined reference set obtained by telemeter implantation. This approach allowed us to compare the severity of individual animals in the experimental subgroups using the maximum achieved severity (RELSAmax). With this, the following order of severity was found for the animal models: CCl4 < PDA {approx} Pancreatitis < BDL. Furthermore, the robustness of the RELSA procedure and outcome was externally validated with a reference set from another laboratory also obtained from telemeter implantation. Since the RELSA procedure reflects the multi-dimensional severity information and is highly robust in estimating the quantitative severity within and between models, it can be deemed a valuable tool for laboratory animal severity assessment.

animal behavior and cognition↗

bioRxiv2022

Experimenter familiarization is a crucial prerequisite for assessing behavioral outcomes and reduces stress in mice not only under chronic pain conditions

ABSTARCTRodent behavior is affected by different environmental conditions. These do not only comprise experimental and housing conditions but also familiarization with the experimenter. However, specific effects on pain-related behavior and chronic pain conditions have not been examined. Therefore, we aimed to investigate the impact of different housing conditions, inverted day-night cycles, and experimenter familiarization on male mice following peripheral neuropathy using the spared nerve injury (SNI) model. Using a multimodal approach, we evaluated evoked pain-related-, anxiety- and depression-like behavior, corticosterone metabolite levels and utilized an integrative approach for relative-severity-assessment. Different environmental conditions are represented by individually ventilated cages and standard open cages combined with a reversed day-night-light cycle and experimenter habituation, inducing differentially modulated multidimensional pain- and emotion-like phenotypes in SNI mice. In addition, familiarization reduced the stress level caused by behavioral tests. Although no environmental condition significantly modulated the severity in SNI mice, it influenced pain-affected phenotypes and is, therefore, crucial for designing and interpreting preclinical pain studies. Moreover, environmental conditions should be considered more in the reporting guidelines, described in more detail, and discussed as a potential influence on pain phenotypes.

animal behavior and cognition↗

bioRxiv2022

Establishment of the Body Conditioning Score for adult female Xenopus laevis

The assessment of animals health and nutritional status using a Body Condition Score (BCS) has become a common and reliable tool in lab-animal science. It enables a simple, semi-objective, and non-invasive assessment (palpation of osteal prominences and subcutaneous fat tissue) in routine examination of an animal. In mammals, the BCS classification contains 5 levels: A low score describes a poor nutritional condition (BCS 1-2). A BCS of 3 to 4 is considered optimum, whereas a high score (BCS=5) is associated with obesity. While BCS are published for most common laboratory mammals, these assessment criteria are not directly applicable to clawed frogs (Xenopus laevis) due to their intracoelomic fat body instead of subcutaneous fat tissue. Therefore this assessment tool is still missing for Xenopus laevis. The present study aimed to establish a species-specific BCS for clawed frogs in terms of experimental refinement. Accordingly, 62 adult female Xenopus laevis were weighed and sized. Further, the body contour was defined, classified, and assigned to BCS groups. A BCS 5 was associated with a mean body weight of 193.3 g ({+/-} 27.6 g), whereas a BCS 4 ranged at 163.1 g ({+/-}16.0 g). Animals with a BCS=3 had an average body weight of 114.7 g ({+/-}16.7 g). A BCS=2 was determined in 3 animals (103 g, 110 g, and 111 g). One animal had a BCS=1 (83 g), which would be equivalent to a humane endpoint. In conclusion, individual examination using the presented visual BCS provides a quick and easy assessment of nutritional status and overall health of adult female Xenopus laevis. Due to their ectothermic nature and the associated special metabolic situation, it can be assumed that a BCS [≥]3 is to be preferred for female Xenopus laevis. In addition, BCS assessment may indicate underlying subclinical health problems that require further diagnostic investigation.

animal behavior and cognition↗

bioRxiv2020

One score to rule them all: severity assessment in laboratory mice

Animal welfare and the refinement of experimental procedures are fundamental aspects of biomedical research. They provide the basis for robust experimental designs and reproducibility of results. In many countries, the determination of welfare is a mandatory legal requirement and implies the assessment of the degree of the severity that an animal experiences during an experiment. However, for an effective severity assessment, an objective and exact approach/system/strategy is needed. In light of these demands, we have developed the Relative Severity Assessment (RELSA) score.This comprehensive composite score was established on the basis of physiological and behavioral data from a surgical mouse study. Body weight, the Mouse Grimace Scale score, burrowing behavior, and the telemetry-derived parameters heart rate, heart rate variability, temperature, and general activity were used to investigate the quality of indicating severity during postoperative recovery. The RELSA scores not only revealed individual severity levels but also allowed a comparison of severity in distinct mouse models addressing colitis, sepsis, and restraint stress using a k-means clustering approach with the maximum achieved RELSA scores.We discriminated and classified data from sepsis nonsurvivors into the highest relative severity level. Data from mice after intraperitoneal transmitter implantation and sepsis survivor al were located in the next lower cluster, while data from mice subjected to colitis and restraint stress were placed in the lowest severity cluster. Analysis of individual variables and their combinations revealed model- and time-dependent contributions to severity levels.In conclusion, we propose the RELSA score as a validated tool for objective real-time applicability in severity assessment and as a first step towards a unified and accessible risk assessment tool in biomedical research. As an effective severity assessment system, it will fundamentally improve animal welfare, as well as data quality and reproducibility.Competing Interest StatementThe authors have declared no competing interest.View Full Text

animal behavior and cognition↗