The ethical challenges of animal research

Renal proximal tubule-on-a-chip in PDMS: fabrication, functionalization, and RPTEC:HUVEC co-culture evaluation

'On-a-chip' technology advances the development of physiologically relevant organ-mimicking architecture by integrating human cells into three-dimensional microfluidic devices. This method also establishes discrete functional units, faciliting focused research on specific organ components. In this study, we detail the development and assessment of a convoluted renal proximal tubule-on-a-chip (PT-on-a-chip). This platform involves co-culturing Renal Proximal Tubule Epithelial Cells (RPTEC) and Human Umbilical Vein Endothelial Cells (HUVEC) within a polydimethylsiloxane microfluidic device, crafted through a combination of 3D printing and molding techniques. Our PT-on-a-chip significantly reduced high glucose level, exhibited albumin uptake, and simulated tubulopathy induced by amphotericin B. Remarkably, the RPTEC:HUVEC co-culture exhibited efficient cell adhesion within 30 min on microchannels functionalized with plasma, 3-aminopropyltriethoxysilane, and type-I collagen. This approach significantly reduced the required incubation time for medium perfusion. In comparison, alternative methods such as plasma and plasma plus polyvinyl alcohol were only effective in promoting cell attachment to flat surfaces. The PT-on-a-chip holds great promise as a valuable tool for assessing the nephrotoxic potential of new drug candidates, enhancing our understanding of drug interactions with co-cultured renal cells, and reducing the need for animal experimentation, promoting the safe and ethical development of new pharmaceuticals.

When Is Something an Alternative? A General Account Applied to Animal-Free Alternatives to Animal Research

The first "R" from animal research ethics prescribes the replacement of animal experiments with animal-free alternatives. However, the question of when an animal-free method qualifies as an alternative to animal experiments remains unresolved.Drawing lessons from another debate in which the word "alternative" is central, the ethical debate on alternatives to germline genome editing, this paper develops a general account of when something qualifies as an alternative to something. It proposes three ethically significant conditions that technique, method, or approach X must meet to qualify as an alternative to Y: (1) X must address the same problem as Y, under an appropriate description of that problem; (2) X must have a reasonable chance of success, compared to Y, in solving the problem; and (3) X must not be ethically unacceptable as a solution. If X meets all these conditions, its relative advantages and disadvantages determine whether it is preferable, indifferent, or dispreferable as an alternative to Y.This account is then applied to the question of whether animal-free research methods qualify as alternatives to animal research. Doing so breaks down the debate around this question into more focused (ethical and other) issues and illustrates the potential of the account.

Student insights towards animal welfare science and law. Survey results from Sassari University, Italy

In this paper, we describe the results of an online survey consisting of 23 questions created to evaluate the knowledge and interest on animal welfare by students attending 15 different scientific, medical, and biomedical courses at University of Sassari, Italy. The survey collected students' demographic data, level of knowledge both on animal welfare and 3Rs, as well as their opinions on animal experimentation. The majority of the cohort was female and over 24 years of age. About a third of the students responded that their graduate programme included subjects that taught science, ethics, and animal welfare legislation. Just 21.2% of respondents had heard about the concept of 3Rs. About a quarter of the students believed that animal models can be replaced by in vitro and in silico methods while half believed that both are needed. However, 70% of the participants did not know the existence of an Ethics and Animal Welfare Committee. The result showed the importance of an Animal Welfare Course for the professional future of a larger number of students and underlined the key role of veterinary medicine in promoting ethics and animal experimentation.

Toward an Anti-Maleficent Research Agenda

Important advances in biomedical and behavioral research ethics have occurred over the past few decades, many of them centered on identifying and eliminating significant harms to human subjects of research. Comprehensive attention has not been paid to the totality of harms experienced by animal subjects, although scientific and moral progress require explicit appraisal of these harms. Science is a public good and the prioritizing within, conduct of, generation of, and application of research must soundly address questions about which research is morally defensible and valuable enough to support through funding, publication, tenure, and promotion. Likewise, educational pathways of re-imagined science are critical.

Preparation and Culture of Organotypic Hippocampal Slices for the Analysis of Brain Metastasis and Primary Brain Tumor Growth

Brain metastasis is a major challenge for therapy and defines the end stage of tumor progression with a very limited patients' prognosis. Experimental setups that faithfully mimic these processes are necessary to understand the mechanism of brain metastasis and to develop new improved therapeutic strategies. Here, we describe an in vitro model, which closely resembles the in vivo situation. Organotypic hippocampal brain slice cultures (OHSCs) prepared from 3- to 8-day-old mice are well suited for neuro-oncology research including brain metastasis. The original morphology is preserved in OHSCs even after culture periods of several days to weeks. Tumor cells or cells of metastatic origin can be seeded onto OHSCs to evaluate micro-tumor formation, tumor cell invasion, or treatment response. We describe preparation and culture of OHSCs including the seeding of tumor cells. Finally, we show examples of how to treat the OHSCs for life-dead or immunohistochemical staining.

Alternative strategies in cardiac preclinical research and new clinical trial formats

An efficient and safe drug development process is crucial for the establishment of new drugs on the market aiming to increase quality of life and life-span of our patients. Despite technological advances in the past decade, successful launches of drug candidates per year remain low. We here give an overview about some of these advances and suggest improvements for implementation to boost preclinical and clinical drug development with a focus on the cardiovascular field. We highlight advantages and disadvantages of animal experimentation and thoroughly review alternatives in the field of three-dimensional cell culture as well as preclinical use of spheroids and organoids. Microfluidic devices and their potential as organ-on-a-chip systems, as well as the use of living animal and human cardiac tissues are additionally introduced. In the second part, we examine recent gold standard randomized clinical trials and present possible modifications to increase lead candidate throughput: adaptive designs, master protocols, and drug repurposing. In silico and N-of-1 trials have the potential to redefine clinical drug candidate evaluation. Finally, we briefly discuss clinical trial designs during pandemic times.

Enzyme-digested Colla Corii Asini (E'jiao) accelerates wound healing and prevents ultraviolet A-induced collagen synthesis decline and wrinkle formation in three-dimensional skin equivalents

Cutaneous wound healing delay, collagen synthesis decline and wrinkle formation are the common features of skin aging. The aim of this study is to investigate repressive effects of Colla Corii Asini (CCA) (a traditional Chinese medicine which has been used for anti-aging) on hydrogen peroxide (300 µM, 2 h) and ultraviolet A (UVA) (3.2 mJ/cm²)-induced skin aging in vitro. To simulate the in vivo condition of CCA, CCA was digested by gastrointestinal enzymes and added to human gingival fibroblasts (HGF) and three dimensional (3D) skin equivalents at different concentrations. Cell viability assay showed that the enzyme-digested CCA (CCAD) exhibited significant preventive effects on hydrogen peroxide- and UVA-induced cell death. The in vitro scratch assay showed that CCAD was able to prevent hydrogen peroxide-induced wound healing delay in HGF cell sheets. Immunostaining and imaging analysis showed that CCAD could suppress UVA-reduced expression of type IV collagen and elastin in both HGF cells and the 3D skin equivalents. Using a tissue stretching system, wrinkles were formed on UVA-irradiated 3D skin equivalents. Without CCAD-treatment, the wrinkles on the skin were deep, whereas CCAD markedly reduced the depth of wrinkles. In conclusion, CCAD could protect skin cells from oxidative stress and UVA-induced harmful effects, accelerate wound healing, promote synthesis of collagen and elastin, and reduce wrinkles formation. CCAD might be developed as an anti-skin aging reagent in the cosmetic industry.

The Emergence and Development of Animal Research Ethics: A Review with a Focus on Nonhuman Primates

The ethics of using nonhuman animals in biomedical research is usually seen as a subfield of animal ethics. In recent years, however, the ethics of animal research has increasingly become a subfield within research ethics under the term "animal research ethics". Consequently, ethical issues have become prominent that are familiar in the context of human research ethics, such as autonomy or self-determination, harms and benefits, justice, and vulnerability. After a brief overview of the development of the field and a discussion of relevant theoretical ethical frameworks, I consider two of these issues, namely autonomy and self-determination on the one hand, and harms and benefits on the other hand. My concern is with philosophical and ethical issues, rather than animal research oversight. I focus my discussion on nonhuman primates, as the most plausible nonhuman candidates for this approach. I conclude that the approach, although promising, depends strongly on the moral status of nonhuman research subjects.

Statistical significance: p value, 0.05 threshold, and applications to radiomics-reasons for a conservative approach

Here, we summarise the unresolved debate about p value and its dichotomisation. We present the statement of the American Statistical Association against the misuse of statistical significance as well as the proposals to abandon the use of p value and to reduce the significance threshold from 0.05 to 0.005. We highlight reasons for a conservative approach, as clinical research needs dichotomic answers to guide decision-making, in particular in the case of diagnostic imaging and interventional radiology. With a reduced p value threshold, the cost of research could increase while spontaneous research could be reduced. Secondary evidence from systematic reviews/meta-analyses, data sharing, and cost-effective analyses are better ways to mitigate the false discovery rate and lack of reproducibility associated with the use of the 0.05 threshold. Importantly, when reporting p values, authors should always provide the actual value, not only statements of "p < 0.05" or "p ≥ 0.05", because p values give a measure of the degree of data compatibility with the null hypothesis. Notably, radiomics and big data, fuelled by the application of artificial intelligence, involve hundreds/thousands of tested features similarly to other "omics" such as genomics, where a reduction in the significance threshold, based on well-known corrections for multiple testing, has been already adopted.

Hematological reference values and animal welfare parameters of BALB/C-FMABC (Mus musculus) inoculated with Ehrlich tumor kept in the vivarium at ABC Medical School

BACKGROUND

Biochemical and hematological parameters are important tools for assessing the physiological profile of vital organs, and can be recorded to create reference values used for clinical diagnosis of diseases. Many research laboratories lack the means to establish their own set of reference parameters for use in their research, and while there are articles in the literature that discuss laboratory parameters for healthy BALB/c mice, few studies address the evaluation of these parameters in pathological situations, such as in mice inoculated with Ehrlich tumor.

METHOD

BALB/c-FMABC mice previously inoculated with Ehrlich tumor were maintained under appropriate conditions. Blood samples were taken for analysis of hematological parameters using automated and semi-automated equipment to create a set of the animal welfare parameters for evaluation.

RESULT

Results were obtained for all the hematological parameters for all groups analyzed. These showed: statistically significant differences between the initial and final tumor weight; comparable initial tumour volume and weight; an increase in leukocytes in the 7-day group with a characteristic predominance of lymphocytes and neutrophils; statistically significant changes in RDW in the 21-day group and in the welfare parameters in the 28-day group.

CONCLUSION

The study successfully defined and established reference values for hematological and welfare parameters for all groups analyzed.

The zebrafish tail immobilization (ZTI) test as a new tool to assess stress-related behavior and a potential screen for drugs affecting despair-like states

BACKGROUND

Affective disorders, especially depression and anxiety, are highly prevalent, debilitating mental illnesses. Animal experimental models are a valuable tool in translational affective neuroscience research. A hallmark phenotype of clinical and experimental depression, the learned helplessness, has become a key target for 'behavioral despair'-based animal models of depression. The zebrafish (Danio rerio) has recently emerged as a promising novel organism for affective disease modeling and CNS drug screening. Despite being widely used to assess stress and anxiety-like behaviors, there are presently no clear-cut despair-like models in zebrafish.

NEW METHOD

Here, we introduce a novel behavioral paradigm, the zebrafish tail immobilization (ZTI) test, as a potential tool to assess zebrafish despair-like behavior. Conceptually similar to rodent 'despair' models, the ZTI protocol involves immobilizing the caudal half of the fish body for 5 min, leaving the cranial part to move freely, suspended vertically in a small beaker with water.

RESULTS

To validate this model, we used exposure to low-voltage electric shock, alarm pheromone, selected antidepressants (sertraline and amitriptyline) and an anxiolytic drug benzodiazepine (phenazepam), assessing the number of mobility episodes, time spent 'moving', total distance moved and other activity measures of the cranial part of the body, using video-tracking. Both electric shock and alarm pheromone decreased zebrafish activity in this test, antidepressants increased it, and phenazepam was inactive. Furthermore, a 5-min ZTI exposure increased serotonin turnover, elevating the 5-hydroxyindoleacetic acid/serotonin ratio in zebrafish brain, while electric shock prior to ZTI elevated both this and the 3,4-dihydroxyphenylacetic acid/dopamine ratios. In contrast, preexposure to antidepressants sertraline and amitriptyline lowered both ratios, compared to the ZTI test-exposed fish.

COMPARISON WITH EXISTINGMETHOD(S)

The ZTI test is the first despair-like experimental model in zebrafish.

CONCLUSIONS

Collectively, this study suggests the ZTI test as a potentially useful protocol to assess stress-/despair-related behaviors, potentially relevant to CNS drug screening and behavioral phenotyping of zebrafish.

The current state of animal models in research: A review

Animal models have provided invaluable information in the pursuit of medical knowledge and alleviation of human suffering. The foundations of our basic understanding of disease pathophysiology and human anatomy can largely be attributed to preclinical investigations using various animal models. Recently, however, the scientific community, citing concerns about animal welfare as well as the validity and applicability of outcomes, has called the use of animals in research into question. In this review, we seek to summarize the current state of the use of animal models in research.

A Belmont Report for Animals?

Human and animal research both operate within established standards. In the United States, criticism of the human research environment and recorded abuses of human research subjects served as the impetus for the establishment of the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research, and the resulting Belmont Report. The Belmont Report established key ethical principles to which human research should adhere: respect for autonomy, obligations to beneficence and justice, and special protections for vulnerable individuals and populations. While current guidelines appropriately aim to protect the individual interests of human participants in research, no similar, comprehensive, and principled effort has addressed the use of (nonhuman) animals in research. Although published policies regarding animal research provide relevant regulatory guidance, the lack of a fundamental effort to explore the ethical issues and principles that should guide decisions about the potential use of animals in research has led to unclear and disparate policies. Here, we explore how the ethical principles outlined in the Belmont Report could be applied consistently to animals. We describe how concepts such as respect for autonomy and obligations to beneficence and justice could be applied to animals, as well as how animals are entitled to special protections as a result of their vulnerability.

La responsabilidad: un principio para retomar en la reflexión bioética

La ciencia y su brazo, la tecnología, pueden centrarse en una lógica antropocéntrica en la medida en que se empecinen en satisfacer únicamente las necesidades humanas a expensas del dominio (o destrucción) de la naturaleza y las especies coexistentes. También es posible que se pongan al servicio de poderes económicos y políticos y se investigue únicamente bajo una lógica centrada en la ganancia. En medio de este panorama, se hace un llamado a un acto de conciencia para retomar la propuesta del filósofo alemán Hans Jonas sobre el principio de responsabilidad, según el cual, es necesaria una reflexión más allá de las relaciones inmediatas, que incluya a la naturaleza, los animales y las generaciones futuras en la formulación de una nueva ética que debe enseñarse y practicarse desde la academia.

Design of a cost-effective, hemodynamically adjustable model for resuscitative endovascular balloon occlusion of the aorta (REBOA) simulation

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct technique for salvaging patients with noncompressible torso hemorrhage. Current REBOA training paradigms require large animals, virtual reality simulators, or human cadavers for acquisition of skills. These training strategies are expensive and resource intensive, which may prevent widespread dissemination of REBOA. We have developed a low-cost, near-physiologic, pulsatile REBOA simulator by connecting an anatomic vascular circuit constructed out of latex and polyvinyl chloride tubing to a commercially available pump. This pulsatile simulator is capable of generating cardiac outputs ranging from 1.7 to 6.8 L/min with corresponding arterial blood pressures of 54 to 226/14 to 121 mmHg. The simulator accommodates a 12 French introducer sheath and a CODA balloon catheter. Upon balloon inflation, the arterial waveform distal to the occlusion flattens, distal pulsation within the simulator is lost, and systolic blood pressures proximal to the balloon catheter increase by up to 62 mmHg. Further development and validation of this simulator will allow for refinement, reduction, and replacement of large animal models, costly virtual reality simulators, and perfused cadavers for training purposes. This will ultimately facilitate the low-cost, high-fidelity REBOA simulation needed for the widespread dissemination of this life-saving technique.

Glycosaminoglycan-Based Biohybrid Hydrogels: A Sweet and Smart Choice for Multifunctional Biomaterials

Glycosaminoglycans (GAGs) govern important functional characteristics of the extracellular matrix (ECM) in living tissues. Incorporation of GAGs into biomaterials opens up new routes for the presentation of signaling molecules, providing control over development, homeostasis, inflammation, and tumor formation and progression. Recent approaches to GAG-based materials are reviewed, highlighting the formation of modular, tunable biohybrid hydrogels by covalent and non-covalent conjugation schemes, including both theory-driven design concepts and advanced processing technologies. Examples of the application of the resulting materials in biomedical studies are provided. For perspective, solid-phase and chemoenzymatic oligosaccharide synthesis methods for GAG-derived motifs, rational and high-throughput design strategies for GAG-based materials, and the utilization of the factor-scavenging characteristics of GAGs are highlighted.