Animal Models for Anorexia Nervosa—A Systematic Review

Abstract

Anorexia nervosa is an eating disorder characterized by intense fear of gaining weight and a distorted body image which usually leads to low caloric intake and hyperactivity. The underlying mechanism and pathogenesis of anorexia nervosa is still poorly understood. In order to learn more about the underlying pathophysiology of anorexia nervosa and to find further possible treatment options, several animal models mimicking anorexia nervosa have been developed. The aim of this review is to systematically search different databases and provide an overview of existing animal models and to discuss the current knowledge gained from animal models of anorexia nervosa. For the systematic data search, the Pubmed—Medline database, Embase database, and Web of Science database were searched. After removal of duplicates and the systematic process of selection, 108 original research papers were included in this systematic review. One hundred and six studies were performed with rodents and 2 on monkeys. Eighteen different animal models for anorexia nervosa were used in these studies. Parameters assessed in many studies were body weight, food intake, physical activity, cessation of the estrous cycle in female animals, behavioral changes, metabolic and hormonal alterations. The most commonly used animal model (75 of the studies) is the activity-based anorexia model in which typically young rodents are exposed to time-reduced access to food (a certain number of hours a day) with unrestricted access to a running wheel. Of the genetic animal models, one that is of particular interest is the anx/anx mice model. Animal models have so far contributed many findings to the understanding of mechanisms of hunger and satiety, physical activity and cognition in an underweight state and other mechanisms relevant for anorexia nervosa in humans.

Is the Activity-Based Anorexia Model a Reliable Method of Presenting Peripheral Clinical Features of Anorexia Nervosa?

“…Thus, it would be unrealistic to build an animal model upon the entire AN pathology. Still, ABA is not only highly similar to AN, but it is also considered the best animal model of any psychiatric disorder [ 12 , 13 , 14 ]. ABA successfully captures numerous clinical features of anorexia nervosa, such as severe weight loss, hunger-induced hyperactivity, anxiety, cessation of the estrous cycle (females), and heightened vulnerability during puberty [ 7 ].…”

Exploring the Mechanisms of Recovery in Anorexia Nervosa through a Translational Approach: From Original Ecological Measurements in Human to Brain Tissue Analyses in Mice

“…However, persistence of symptoms after weight gain, illustrated here through treatment-seeking patients with prAN, has to be further investigated. The interaction between physical activity, caloric restriction and weight loss has been widely described and explored with various rodent models mimicking several physiological, metabolic and endocrine aspects of AN [ 32 , 50 , 51 ]. We further investigated such models here.…”

“…For this purpose, using preclinical models is a prerequisite to better understand mechanisms involved in the remission or relapse of AN. Several animal models are now available to assess the various aspects of AN [ 32 , 49 , 50 , 51 , 52 ]. Using the “activity based-anorexia” (ABA) model, Verhagen et al (2011) demonstrate that central leptin injections in the lateral ventricle or local injections of leptin into the ventral tegmental area suppress the running wheel activity [ 53 ].…”

A Framework for Developing Translationally Relevant Animal Models of Stress-Induced Changes in Eating Behavior

“…Recommendations: Ideally, the development of a consensus on several standardized assays that could be used as battery to evaluate stress related feeding would permit comparisons between groups, enhancing the rigor and reproducibility of the research, as shown for models of anorexia-like and binge eating behaviors (reviewed in (16,17)). Until that happens, there are several ways to increase the impact of studies by individual groups.…”

“…This relationship between stress and feeding in rodents is best studied in the context of pathophysiological eating behaviors. Rodent paradigms to model binge eating behavior and activity-based anorexia produce a consistent and robust increase or suppression of food intake, respectively (reviewed in (16,17)). Standardization of these assays has permitted comparisons of findings between labs and across species that are critical to establish relevance to humans.…”