From replica to instruments: animal models in biomedical research

Evaluating the validity of animal models of mental disorder: from modeling syndromes to modeling endophenotypes

This paper provides a historical analysis of a shift in the way animal models of mental disorders were conceptualized: the shift from the mid-twentieth-century view, adopted by some, that animal models model syndromes classified in manuals such as the Diagnostic and Statistical Manual of Mental Disorders (DSM), to the later widespread view that animal models model component parts of psychiatric syndromes. I argue that in the middle of the twentieth century the attempt to maximize the face validity of animal models sometimes led to the pursuit of the ideal of an animal model that represented a behaviorally defined psychiatric syndrome as described in manuals such as the DSM. I show how developments within psychiatric genetics and related criticism of the DSM in the 1990s and 2000s led to the rejection of this ideal and how researchers in the first decade of the twenty-first century came to believe that animal models of mental disorders should model component parts of mental disorders, adopting a so-called endophenotype approach.

Model-as-replica, model-as-instrument: Representational power and contextual versatility in animal models

Existing scholarship on animal models tends to foreground either of the two major roles research organisms play in different epistemic contexts, treating their representational and instrumental roles separately. Based on an empirical case study, this article explores the changing relationship between the two epistemic roles of a research organism over the span of a decade, while the organism was used to achieve various knowledge ends. This rat model was originally intended as a replica of human susceptibility to cardiac arrest. In a fortunate stroke of serendipity, however, the experimenters detected the way mother-infant interactions regulated the pups' resting cardiac rate. This intriguing outcome thus became the model's new representational target and began driving the development of an experimental system. Henceforth, the model acquired an instrumental function, serving to detect and measure system-specific differences. Its subsequent development involved creating stimulus-response measures to explain and theorize those differences. It was this instrumental use of the model that pushed the experimenters into unchartered territory and conferred to the model an ability to adapt to varied epistemic contexts. Despite the prominence of this instrumental role, however, the model's representational power continued to guide research. The model's representational target was widened beyond heart rate to reflect other functional phenomena, such as behavioral activity and sleep/wake rhythm. The rat model was thus transformed from an experimental organism designed to instantiate cardiac regulation to a model organism taken to represent the development of a whole, intact animal under the regulatory influence of maternal care. This article examines this multifaceted transformation within the context of the salient shifts in modeling practice and variations in the model's representational power. It thus explores how the relationship between the representational and instrumental uses of the model changed with respect to the varying exigencies of the investigative context, foregrounding its contextual versatility.

Medical toolkit organisms and Covid-19

The Covid-19 pandemic has intensified interest in animals with superior antiviral defences. I argue that the role of such animals in biomedical research contrasts with the role of disease models.

Commercial Rodents in America: Standard Animals, Model Animals, and Biological Diversity

Rodents as standardized test animals were developed for commercial distribution in the USA between 1910 and the 1930s. The selective breeding of rats (Rattus norvegicus) and pure-bred mice (Mus musculus) at the Wistar Institute and the Jackson Memorial Laboratories eventually led to a decline in the diversity of species used in American medical and life sciences. The early driving figures, science administrator Milton Greenman and the scientists Henry Donaldson and Clarence Little, sought to standardize animals to render science and its application to humanity more precise. But their efforts were exaggerated in the USA through an expanding industrial and engineering ideal, culminating in a preference for Big Science. I explore the nineteenth century origins of this ideal in Emil Du Bois-Reymond's neurophysiology. This foundation later merged with increasing standardization, American commercialism, and the success of Big Science to transform animal laboratory "standards" into "model animals." Recent accounts of research with commercially bred mice reveal how findings can be co-constructed using human clinical data, as animal research is applied to humans. The neglect of evolutionary perspectives and the dominance of "models" may even have begun with the government's post-war emphasis on funding greater species access for large-scale biomedical research.

Introduction to "Working Across Species"

Comparison between different animal species is omnipresent in the history of science and medicine but rarely subject to focussed historical analysis. The articles in the "Working Across Species" topical collection address this deficit by looking directly at the practical and epistemic work of cross-species comparison. Drawn from papers presented at a Wellcome-Trust-funded workshop in 2016, these papers investigate various ways that comparison has been made persuasive and successful, in multiple locations, by diverse disciplines, over the course of two centuries. They explore the many different animal features that have been considered to be (or else made) comparable, and the ways that animals have shaped science and medicine through the use of comparison. Authors demonstrate that comparison between species often transcended the range of practices typically employed with experimental animal models, where standardised practises and apparatus were applied to standardised bodies to produce generalizable, objective data; instead, comparison across species has often engaged diverse groups of non-standard species, made use of subjective inferences about phenomena that cannot be directly observed, and inspired analogies that linked physiological and behavioural characteristics with the apparent affective state of non-human animals. Moreover, such comparative practices have also provided unusually fruitful opportunities for collaborative connections between different research traditions and disciplines.

Animal extrapolation in preclinical studies: An analysis of the tragic case of TGN1412

According to the received view, the transportation view, animal extrapolation consists in inductive prediction of the outcome of a mechanism in a target, based on an analogical mechanism in a model. Through an analysis of the failure of preclinical studies of TGN1412, an innovative drug, to predict the tragic consequences of its first-in-man trial in 2006, the received view is challenged by a proposed view of animal extrapolation, the chimera view. According to this view, animal extrapolation is based on a hypothesis about how human organisms work, supported by the amalgamation of results drawn from various experimental organisms, and only predicting the 'predictive grid', that is, a global framework of the effects to be expected.