Gut Microbiota Regulates Food Intake in a Rodent Model of Intermittent Limited Access to Palatable Food

IUPHAR review: Eating disorders, gut microbiota dysbiosis and epigenetic aberrations

Eating disorders (EDs) are a heterogeneous class of increasing mental disorders that are characterized by disturbances in eating behaviors, body weight regulation, and associated psychological dysfunctions. These disorders create physiological imbalances that alter the diversity and composition of the gut microbiota. While evidence suggests that EDs can arise from epigenetic aberrations, alterations in gut microbial communities may also contribute to the development and/or persistence of EDs through epigenetic mechanisms. Understanding the interplay among gut microbial communities, epigenetic processes, and the risk of EDs provides opportunities for designing preventive and/or therapeutic interventions through gut microbiome modulation. This review highlights how microbiome-based therapeutics and specific dietary interventions can contribute to improving various subtypes of EDs by modulating gut microbial communities and mitigating epigenetic aberrations. First, we briefly review the literature on links between epigenetic aberrations and the pathophysiology of EDs. Second, we examine the potential role of the gut microbiome in the pathogenesis of EDs through epigenetic mechanisms. Next, we explore the associations between EDs and other psychiatric disorders, and examine the potential roles of the microbiome in their pathogenesis. Finally, we present evidence supporting the potential of microbiome-based therapeutics and specific dietary interventions to improve EDs through epigenetic modifications.

Hunger Games: A Modern Battle Between Stress and Appetite

Stress, an evolutionarily adaptive mechanism, has become a pervasive challenge in modern life, significantly impacting feeding-relevant circuits that play a role in the development and pathogenesis of eating disorders (EDs). Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, disrupts specific neural circuits, and dysregulates key brain regions, including the hypothalamus, hippocampus, and lateral septum. These particular structures are interconnected and key in integrating stress and feeding signals, modulating hunger, satiety, cognition, and emotional coping behaviors. Here we discuss the interplay between genetic predispositions and environmental factors that may exacerbate ED vulnerability. We also highlight the most commonly used animal models to study the mechanisms driving EDs and recent rodent studies that emphasize the discovery of novel cellular and molecular mechanisms integrating stress and feeding signals within the hippocampus-lateral septum-hypothalamus axis. In this review, we discuss the role of gut microbiome, an emerging area of research in the field of EDs and unanswered questions that persist and hinder the scientific progress, such as why some individuals remain resilient to stress while others become at high risk for the development of EDs. We finally discuss the need for future research delineating the impact of specific stressors on neural circuits, clarifying the relevance and functionality of hippocampal-septal-hypothalamic connectivity, and investigating the role of key neuropeptides such as CRH, oxytocin, and GLP-1 in human ED pathogenesis. Emerging tools like single-cell sequencing and advanced human imaging could uncover cellular and circuit-level changes in brain areas relevant for feeding in ED patients. Ultimately, by integrating basic and clinical research, science offers promising avenues for developing personalized, mechanism-based treatments targeting maladaptive eating behavior for patients suffering from EDs.