Beyond the 3Rs: Expanding the use of human-relevant replacement methods in biomedical research

Abstract

20 th century. Relevant techniques include (among others) organson-a-chip (microdevices containing cells and fluids intended to simulate physiological processes in organs); organoids (three-dimensional spheroids containing multiple cell types and intended to simulate physiological processes); high-throughput systems (rapid screening of large numbers of chemicals for biological activity against panels of different cells or biomolecules); induced pluripotent stem cells (adult cells that have been genetically reprogrammed to an embryonic stem cell-like state); and computational modeling (using computation to study the behavior of complex systems).In our view, these methods (and no doubt others in various stages of development) have the potential to replace the use of animals as the default option in both safety testing and biomedical research. That is, these methods will come to comprise the rule, with animal experiments being the exception. This is consistent with Dutch efforts to expeditiously end animal experi- IntroductionThe Principles of Humane Experimental Technique, the landmark book that gave us the 3Rs framework of replacement, reduction, and refinement, turns 60 this year. First published in 1959, Principles was the outcome of a project spearheaded by the Universities Federation for Animal Welfare (UFAW), overseen by a committee that included future Nobel Prize-winning scientist Peter Medawar, and carried out by the British scientists William Russell and Rex Burch (Russell and Burch, 1959). The 3Rs framework helped to inspire and guide humane progress in experimental technique during the second half of the 20 th century and beyond (Stephens and Mak, 2013;Balls et al., 2019).The 60 th anniversary of Principles falls in the midst of substantial developments in non-animal methods, i.e., potential replacement technology. Indeed, scientific experimentation is at the cusp of a new era of techniques hardly imagined in the mid-Food for Thought …

Facilitating Drug Discovery in Human Disease Models Using Insects

“…In the 3Rs, an international principle of experiments using mammals, the use of alternative animals (replacement), pain relief (refinement), and reduction of the number of animals used (reduction) are proposed. 10) Experiments with invertebrates including insects are consistent with the concept of replacement. Invertebrates generally have the following advantages compared with mammals: 1) lower breeding costs; 2) more individuals can be reared in smaller spaces; 3) fewer ethical problems when euthanized; and 4) smaller tissue samples needed due to smaller body sizes (Table 1).…”

“…Attempts have been made to use invertebrates such as nematodes (Caenorhabditis elegans), fruit flies (Drosophila melanogaster), greater wax moths (Galleria mellonella), and silkworms (Bombyx mori) as models for drug discovery research. [6][7][8][9][11][12][13][14] Nematodes and fruit flies have advantages in genetic research, but because of their small size it is difficult to perform quantitative administration of sample solutions into their blood and perform biochemical experiments that require insect blood samples (Table 1). Therefore, there has been little research on the screening and optimization of compounds based on the evaluation of therapeutic effects by injection.…”

“…9) Furthermore, in silkworm experiments, researchers can distinguish between intrahemolymph injection and intramidgut injection. 9,[15][16][17] The former corresponds to intravenous injection in humans, and the latter to oral administration. The injection techniques are important for the evaluation of pharmacokinetics and sample toxicity.…”

“…However, the use of large numbers of mammals, such as mice and rats, causes cost and ethical problems. Recently, the focus has been on insects as useful animals in the initial stage of basic study to seek drug candidates that show therapeutic effects [6][7][8][9] (Fig. 1).…”

“But It’s Just a Fish”: Understanding the Challenges of Applying the 3Rs in Laboratory Aquariums in the UK

“…This is because this is where the vast majority of fish research in the UK is conducted. This is additionally justified because there is already a disproportionate focus on toxicology research in the 3Rs literature [82,83]. Lasting, on average, around one and a half hours, interviews were conducted, where possible, at the place of work of the interviewee.…”