Stress, sex, and the enteric nervous system

Sex shapes gut-microbiota-brain communication and disease

Research into the microbiota-gut-brain axis (MGBA) has entered a golden age, raising the hope that therapeutics acting on it may offer breakthroughs in the treatment of many illnesses. However, most of this work overlooks a fundamental, yet understudied, biological variable: sex. Sex differences exist at every level of the MGBA. Sex steroids shape the structure of the gut microbiota, and these microbes in turn regulate levels of bioactive sex steroids. These hormones and microbes act on gut sensory enteroendocrine cells, which modulate downstream activity in the enteric nervous system, vagus nerve, and brain. We examine recent advances in this field, and discuss the scientific and moral imperative to include females in biomedical research, using autism spectrum disorder (ASD) as an example.

Intestinal retentive systems - recent advances and emerging approaches

Intestinal retentive devices (IRDs) are devices designed to anchor within the lumen of the intestines for long-term residence in the gastrointestinal tract. IRDs can enable impactful medical device technologies including sustained oral drug delivery systems, indwelling sensors, or real-time diagnostics. The design and testing of IRDs present a myriad of challenges, including precise deployment of the device at desired intestinal locations, secure anchoring within the gastrointestinal tract to allow for natural function, and safe removal of the IRD at user-defined times. Advancing the state-of-the-art of IRD is an interdisciplinary effort that requires innovations such as new materials, novel anchoring mechanisms, and medical device design with consistent input from clinical practitioners and end-users. This perspective briefly reviews the current state-of-the-art for IRDs and charts a path forward to inform the design of future concepts. Specifically, this article will highlight materials, retention mechanisms, and test beds to measure the efficacy of IRDs and their mechanisms. Finally, potential synergies between IRD and other medical device technologies are presented to identify future opportunities.

Endo Belly: What Is It and Why Does It Happen?-A Narrative Review

Endometriosis is a chronic inflammatory disease where endometrial-like lesions settle outside the uterus, resulting in extensive inflammatory reactions. It is a complex disease that presents with a range of symptoms, with pain and infertility being the most common. Along with severe dysmenorrhea, cyclic and acyclic lower abdominal pain, cyclic dysuria and dyschezia, dyspareunia, and infertility, there are also nonspecific complaints that can cause confusion and make endometriosis the chameleon among gynecological diseases. These symptoms include unspecific intestinal complaints, cyclic diarrhea, but also constipation, nausea, vomiting, and stomach complaints. It appears that in addition to general bowel symptoms, there are also specific symptoms related to endometriosis such as cyclic bloating of the abdomen, known as endo belly. During the second half of the menstrual cycle leading up to menstruation, the abdomen becomes increasingly bloated causing discomfort and pain due to elevated sensitivity of the intestinal wall. Patients with endometriosis exhibit a reduced stretch pain threshold of the intestinal wall. Here, we review the endo belly, for the first time, pathophysiology and the influence of other diseases (such as irritable bowel syndrome-IBS), microbiome, hormonal levels, inflammation, and diet on the presentation of this condition.

The leaky gut and the gut microbiome in sepsis - targets in research and treatment

Both a leaky gut (a barrier defect of the intestinal surface) and gut dysbiosis (a change in the intestinal microbial population) are intrinsic to sepsis. While sepsis itself can cause dysbiosis, dysbiosis can worsen sepsis. The leaky gut syndrome refers to a status with which there is an increased intestinal permeability allowing the translocation of microbial molecules from the gut into the blood circulation. It is not just a symptom of gastrointestinal involvement, but also an underlying cause that develops independently, and its presence could be recognized by the detection, in blood, of lipopolysaccharides and (1→3)-β-D-glucan (major components of gut microbiota). Gut-dysbiosis is the consequence of a reduction in some bacterial species in the gut microbiome, as a consequence of intestinal mucosal immunity defect, caused by intestinal hypoperfusion, immune cell apoptosis, and a variety of enteric neuro-humoral-immunity responses. A reduction in bacteria that produce short-chain fatty acids could change the intestinal barriers, leading to the translocation of pathogen molecules, into the circulation where it causes systemic inflammation. Even gut fungi might be increased in human patients with sepsis, even though this has not been consistently observed in murine models of sepsis, probably because of the longer duration of sepsis and also antibiotic use in patients. The gut virobiome that partly consists of bacteriophages is also detectable in gut contents that might be different between sepsis and normal hosts. These alterations of gut dysbiosis altogether could be an interesting target for sepsis adjuvant therapies, e.g., by faecal transplantation or probiotic therapy. Here, current information on leaky gut and gut dysbiosis along with the potential biomarkers, new treatment strategies, and future research topics are mentioned.

Understanding the Connection between Gut Homeostasis and Psychological Stress

Long-term exposure to adverse life events that provoke acute or chronic psychological stress (hereinafter "stress") can negatively affect physical health and even increase susceptibility to psychological illnesses, such as anxiety and depression. As a part of the hypothalamic-pituitary-adrenal axis, corticotropin-releasing factor (CRF) released from the hypothalamus is primarily responsible for the stress response. Typically, CRF disrupts the gastrointestinal system and leads to gut microbiota dysbiosis, thereby increasing risk of functional gastrointestinal diseases, such as irritable bowel syndrome. Furthermore, CRF increases oxidative damage to the colon and triggers immune responses involving mast cells, neutrophils, and monocytes. CRF even affects the differentiation of intestinal stem cells (ISCs), causing enterochromaffin cells to secrete excessive amounts of 5-hydroxytryptamine (5-HT). Therefore, stress is often accompanied by damage to the intestinal epithelial barrier function, followed by increased intestinal permeability and bacterial translocation. There are multi-network interactions between the gut microbiota and stress, and gut microbiota may relieve the effects of stress on the body. Dietary intake of probiotics can provide energy for ISCs through glycolysis, thereby alleviating the disruption to homeostasis caused by stress, and it significantly bolsters the intestinal barrier, alleviates intestinal inflammation, and maintains endocrine homeostasis. Gut microbiota also directly affect the synthesis of hormones and neurotransmitters, such as CRF, 5-HT, dopamine, and norepinephrine. Moreover, the Mediterranean diet enhances the stress resistance to some extent by regulating the intestinal flora. This article reviews recent research on how stress damages the gut and microbiota, how the gut microbiota can improve gut health by modulating injury due to stress, and how the diet relieves stress injury by interfering with intestinal microflora. This review gives insight into the potential role of the gut and its microbiota in relieving the effects of stress via the gut-brain axis.

Association between Family Support, Stress, and Sleep Quality among College Students during the COVID-19 Online Learning Period

(1) Background: During the past 3 years, the COVID-19 pandemic has severely affected the normal school schedule of college students, jeopardizing their mental health, sleep quality, and interpersonal relationships. However, previous studies have focused on the dimension of social support received, and few studies have measured in depth the association of support received from family on adolescents’ physical and mental health. Therefore, this study explored the associations between family support received by Chinese college students during COVID-19 pandemic online classes, stress and sleep quality, and the mediating role of stress. (2) Methods: A cross-sectional study conducted at Chongqing Medical University recruited 712 college students through a university-wide incidental random sample using the Questionnaire Star platform. Statistical description and correlation analysis was conducted using SPSS 25.0, and structural equation modeling was constructed using AMOS 22.0 to test for mediating effects; (3) Results: The family support score of college students during the COVID-19 pandemic online course was 19.41 ± 4.62. Correlation analysis showed that sleep quality was negatively correlated with family support (r = −0.224, p < 0.01), positively correlated with stress (r = 0.324, p < 0.01), and family support was negatively correlated with stress (r = −0.159, p < 0.01). The results of structural equation modeling showed that stress partially mediated the relationship between family support and sleep quality among college students (indirect effect = −0.150, p < 0.01, SE = 0.013,95% CI = [−0.208, −0.064]). The model R2 was 36.4%. (4) Conclusions: Schools should consider implementing sleep education, and stress relief curriculum measures to improve the quality of students’ sleep, and should focus on the role that family plays during online classes. This will help students overcome the negative emotional effects of stress in the COVID-19 pandemic and improve their learning efficiency and physical and mental health.

The Effects of Stress and Diet on the "Brain-Gut" and "Gut-Brain" Pathways in Animal Models of Stress and Depression

Compelling evidence is building for the involvement of the complex, bidirectional communication axis between the gastrointestinal tract and the brain in neuropsychiatric disorders such as depression. With depression projected to be the number one health concern by 2030 and its pathophysiology yet to be fully elucidated, a comprehensive understanding of the interactions between environmental factors, such as stress and diet, with the neurobiology of depression is needed. In this review, the latest research on the effects of stress on the bidirectional connections between the brain and the gut across the most widely used animal models of stress and depression is summarised, followed by comparisons of the diversity and composition of the gut microbiota across animal models of stress and depression with possible implications for the gut–brain axis and the impact of dietary changes on these. The composition of the gut microbiota was consistently altered across the animal models investigated, although differences between each of the studies and models existed. Chronic stressors appeared to have negative effects on both brain and gut health, while supplementation with prebiotics and/or probiotics show promise in alleviating depression pathophysiology.

The Pivotal Role of Microbiota in Modulating the Neuronal-Glial-Epithelial Unit

The enteric nervous system (ENS) consists of enteric neurons and enteric glial cells (EGCs) and controls the function of the epithelial barrier. Thus, a novel concept of neuronal–glial–epithelial unit in the gut was put forward by analogy with neuronal–glial–endothelial unit in the brain. The environment in the gastrointestinal (GI) tract is complex as it harbours millions of bacteria, which extensively attach with intestinal epithelium. The cross-talk between the neuronal–glial–endothelial unit and microbiota plays a pivotal role in modulating the epithelial barrier's permeability, intestinal development and immune response. And evidence shows dysbiosis is the potent risk factor in the pathologic process of Parkinson’s disease (PD) and inflammatory bowel disease (IBD). In this review, we summarize the compelling results in favor of microbiota serving as the key modulator in the neuronal–glial–epithelial unit development and function, with profound effects on intestinal homeostasis.

Flupirtine enhances NHE-3-mediated Na+ absorption in rat colon via an ENS-dependent mechanism

Recent studies in our lab have shown that the KV7 channel activator, flupirtine, inhibits colonic epithelial Cl- secretion through effects on submucosal neurons of the enteric nervous system (ENS). We hypothesized that flupirtine would also stimulate Na+ absorption as a result of reduced secretory ENS input to the epithelium. To test this hypothesis, unidirectional 22Na+ fluxes were measured under voltage-clamped conditions. Pharmacological approaches using an Ussing-style recording chamber combined with immunofluorescence microscopy techniques were used to determine the effect of flupirtine on active Na+ transport in the rat colon. Flupirtine stimulated electroneutral Na+ absorption in partially seromuscular-stripped colonic tissues, while simultaneously inhibiting short-circuit current (ISC; i.e., Cl- secretion). Both of these effects were attenuated by pretreatment with the ENS inhibitor, tetrodotoxin. The Na+/H+ exchanger isoform 3 (NHE-3)-selective inhibitor, S3226, significantly inhibited flupirtine-stimulated Na+ absorption, whereas the NHE-2-selective inhibitor HOE-694 did not. NHE-3 localization near the apical membranes of surface epithelial cells was also more apparent in flupirtine-treated colon versus control. Flupirtine did not alter epithelial Na+ channel (ENaC)-mediated Na+ absorption in distal colonic tissues obtained from hyperaldosteronaemic rats and had no effect in the normal ileum but did stimulate Na+ absorption in the proximal colon. Finally, the parallel effects of flupirtine on ISC (Cl- secretion) and Na+ absorption were significantly correlated with each other. Together, these data indicate that flupirtine stimulates NHE-3-dependent Na+ absorption, likely as a result of reduced stimulatory input to the colonic epithelium by submucosal ENS neurons.NEW & NOTEWORTHY We present a novel mechanism regarding regulation of epithelial ion transport by enteric neurons. Activation of neuronal KV7 K+ channels markedly stimulates Na+ absorption and inhibits Cl- secretion across the colonic epithelium. This may be useful in developing new treatments for diarrheal disorders, such as irritable bowel syndrome with diarrhea (IBS-D).

Psychological Distress, Somatic Complaints, and Their Relation to Negative Psychosocial Factors in a Sample of Swedish High School Students

Background: Adolescence is a period in life characterized by major neurobiological, physiological, and psychological changes. Those changes may give rise to worsened mental health and an increased prevalence of somatic complaints combined with a negative psychosocial environment. Rapid changes in society, which may also affect young people in several ways, call for a renewed screening of today's adolescents' mental and somatic well-being. Aim: The present study's primary aim was to measure the level of self-rated psychological distress and the prevalence of somatic complaints in a sample of Swedish high school students. As a secondary aim, it identifies gender-specific patterns and examines mental and somatic health in relation to negative psychosocial factors (such as parental alcohol use problems or the experience of physical or psychological abuse). Method: Two hundred and eighty-seven Swedish high school students completed a survey including the Brief Symptom Inventory (BSI) and a questionnaire about the presence of defined somatic complaints. In order to examine the relationship between negative psychosocial factors and mental and somatic health, three groups were formed: those reporting (i) parental substance use problems, (ii) previous experience of abuse, (iii) none of these problems. Results: The majority of the Swedish high-school students (>80%) reported no or only a few problems with psychological distress and no or only one somatic complaint. Female students disclosed a significantly higher psychological distress level captured by each BSI domain. The number of somatic complaints was similarly distributed between the genders. The students rarely reported parental substance use problems, but almost 40% of the male and 50% of the female students indicated the experience of physical and/or psychological abuse. Such negative psychosocial circumstances were related to an increased level of anxiety in the male and an increased general level of psychological distress in female students. Conclusions: The study confirmed female students' higher psychological distress level. Gender differences in the type of somatic complaints, but not in the number were detected. The experience of physical and/or psychological abuse was found to significantly worsen psychological distress in students of both genders.

Underlying mechanisms for intestinal diseases arising from stress

Stress is an instinctive defense mechanism of the body in the competition for survival, but long-term or chronic stress will lead to systemic pathological manifestations. Intestinal diseases are closely related to pathological stress. This paper reviews the pathogenesis of intestinal diseases arising from stress.

Food, microbes, sex and old age: on the plasticity of gastrointestinal innervation

The gastrointestinal tract is innervated by its own enteric nervous system and by extrinsic neurons that connect it with the central nervous system. Innervation allows the gastrointestinal tract to sense and respond to diverse stimuli, adjusting motility and secretion, but also affecting our physiology, behaviour and immunity. The mechanisms underlying the formation of gastrointestinal neurons are beginning to be elucidated; those that keep them plastic over an organism's lifetime remain to be explored. Here, we review the effects of microbiota, nutrients, sex and ageing on the morphology and function of gastrointestinal innervation in mammals, and discuss how this plasticity shapes gut-brain crosstalk and whole-body physiology. We also highlight insights gained by nascent studies of the enteric innervation of Drosophila melanogaster.

Personality traits are related to functional dyspepsia in a large sample of Iranian adults

BACKGROUND AND OBJECTIVE

Few studies have evaluated the association of personality traits with functional dyspepsia (FD). In the present study, we aimed to explore the relationship between different personality traits and FD in a sample of Iranian adults.

METHODS

This cross-sectional study was conducted on 4763 adults. FD was evaluated using a modified and validated Persian version of the Rome III questionnaire for the diagnosis of functional gastrointestinal disorders. Personality traits were assessed using the five-factor model. Logistic regression was used for data analysis.

RESULTS

After controlling for various potential confounders, neuroticism (OR = 1.043; 95% CI: 1.028, 1.059), agreeableness (OR = 0.965; 95% CI: 0.952, 0.978), extraversion (OR = 0.985; 95% CI: 0.970, 0.990), openness (OR = 0.981; 95% CI: 0.966, 0.996), and conscientious (OR = 0.980; 95% CI: 0.968, 0.991) scores were associated with risk of FD. Similar significant associations were observed in stratified analyses by sex, except for openness which tended to decrease the risk of FD marginally in women (OR = 0.983, 95% CI: 0.966, 1.001) and in men (OR = 0.979, 95% CI: 0.955, 1.003) after adjusting for multiple confounding variables.

CONCLUSION

Our study showed that the higher scores of extraversion, conscientiousness, openness, and agreeableness are independently associated with a lower risk of FD in Iranian general population while higher scores of neuroticism increase the risk of FD.

Can Sertraline and Nortriptyline Protect the Neurons in Submucosal and Myenteric Plexuses of Rat's Colon Against Stress?

BACKGROUND

The colon is partly controlled by myenteric and submucosal plexuses, which respond to stress and lead to some gastrointestinal disorders. These plexuses play roles in irritable bowel syndrome. Patients suffering from this syndrome can be treated with some antidepressants, including sertraline and nortriptyline.

AIMS

The primary aim of study was to compare the effect of a sertraline and a nortriptyline on the structural changes of the enteric neurons after stress exposure in both sexes. The secondary objectives were to evaluate the effects of stress on the submucosal and myenteric plexuses.

METHODS

Male and female Sprague-Dawley rats were assigned to four subgroups. The first subgroup received no stress. The other three subgroups received chronic variable stress (CVS) and were given phosphate buffer, sertraline (10 mg/kg/day), or nortriptyline (10 mg/kg/day). After 45 days, the neuron number in their colon plexuses was estimated using the stereologic method.

RESULTS

The number of neurons increased by 40-51% in the submucosal plexus and by 57-69% in the myenteric plexus in the CVS group compared with the control group (p < 0.002) without any sex preference. The increment was significantly higher in the myenteric plexus than in the submucosal plexus (p < 0.05). Moreover, co-treatment of stressed rats with sertraline and nortriptyline could prevent the cellular hyperplasia of the plexuses, with more effective action for sertraline (p < 0.02).

CONCLUSIONS

Stress exposure for 45 days induced hyperplasia of the colon's enteric plexuses in both sexes. However, these drugs could prevent the changes, with a more effective action for sertraline.

Maternal separation in rodents: a journey from gut to brain and nutritional perspectives

The developmental period constitutes a critical window of sensitivity to stress. Indeed, early-life adversity increases the risk to develop psychiatric diseases, but also gastrointestinal disorders such as the irritable bowel syndrome at adulthood. In the past decade, there has been huge interest in the gut-brain axis, especially as regards stress-related emotional behaviours. Animal models of early-life adversity, in particular, maternal separation (MS) in rodents, demonstrate lasting deleterious effects on both the gut and the brain. Here, we review the effects of MS on both systems with a focus on stress-related behaviours. In addition, we discuss more recent findings showing the impact of gut-directed interventions, including nutrition with pre- and probiotics, illustrating the role played by gut microbiota in mediating the long-term effects of MS. Overall, preclinical studies suggest that nutritional approaches with pro- and prebiotics may constitute safe and efficient strategies to attenuate the effects of early-life stress on the gut-brain axis. Further research is required to understand the complex mechanisms underlying gut-brain interaction dysfunctions after early-life stress as well as to determine the beneficial impact of gut-directed strategies in a context of early-life adversity in human subjects.

Somatic health and its association with negative psychosocial factors in a sample of Moroccan adolescents

Background:

Adolescence is a distinct developmental phase characterized by multiple physical and psychological changes and by an increased vulnerability to somatic and mental health problems. These risk and vulnerability factors are part of a complex biopsychosocial matrix, encompassing multiple factors, such as inherited biological determinants and psychological, societal, and cultural influences, which affect an adolescent’s overall wellbeing. In Morocco, similar to other developing countries, adolescents (young people aged from 15 to 19 years) constitute a substantial proportion of the population (almost 9%). However, studies about adolescents’ health in developing countries are scarce. In this study, we describe adolescents’ somatic health in a sample of high school students from the city of Tetouan, Morocco, and investigate how negative psychosocial factors, such as parental alcohol use problems and/or the experience of abuse, may influence them.

Methods:

The study sample included 655 adolescents (315 boys and 340 girls, M = 16.64 years, range = 15–18 years) from conviniently selected classes of four high schools in the city of Tetouan in Morocco. The students responded to a survey that assessed the prevalence of somatic complaints/disorders. They also indicated whether they had ever experienced physical and/or psychological abuse and whether they had parents with alcohol use problems.

Results:

More than half of the adolescents suffered from headaches and one-third had substantial problems with diarrhea or constipation. Both problems were more common in female students. The third most frequent somatic problem, affecting one in four in both genders, was allergy. Almost one-third of Moroccan adolescents (significantly more boys than girls; p = 0.004) reported no somatic complaints. In adolescents who reported parental alcohol use problems and/or experience of physical and/or psychological abuse, the prevalence of several somatic complaints (epilepsy, migraine, headache, diarrhea/constipation, gluten intolerance, allergy, and skin or thyroid disease) increased highly significantly compared to the adolescents who reported no such psychosocial environmental factors.

Conclusion:

The results suggest that only 3 in 10 urban-living Moroccan adolescents are free of somatic complaints, while the majority suffer from some somatic problems, most often headaches and diarrhea/constipation. The association of certain negative psychosocial factors with adolescents’ somatic health suggests the need of a holistic approach to the treatment of affected adolescents.

Age and Sex-Dependent Differences in the Neurochemical Characterization of Calcitonin Gene-Related Peptide-Like Immunoreactive (CGRP-LI) Nervous Structures in the Porcine Descending Colon

Neurons of the enteric nervous system (ENS) may undergo changes during maturation and aging, but knowledge of physiological stimuli-dependent changes in the ENS is still fragmentary. On the other hand, the frequency of many ENS-related intestinal illnesses depends on age and/or sex. The double immunofluorescence technique was used to study the influence of both of these factors on calcitonin gene-related peptide (CGRP)—positive enteric nervous structures—in the descending colon in young and adult female and castrated male pigs. The influence of age and gender on the number and neurochemical characterization (i.e., co-localization of CGRP with substance P, nitric oxide synthase, galanin, cocaine- and amphetamine-regulated transcript peptide and vesicular acetylcholine transporter) of CGRP-positive nerve structures in the colonic wall has been shown. These observations strongly suggest the participation of CGRP in adaptive processes in the ENS during GI tract maturation. Moreover, although the castration of males may mask some aspects of sex-dependent influences on the ENS, the sex-specific differences in CGRP-positive nervous structures were mainly visible in adult animals. This may suggest that the distribution and exact role of this substance in the ENS depend on the sex hormones.

Stress Triggers Flare of Inflammatory Bowel Disease in Children and Adults

Inflammatory bowel disease (IBD) is an idiopathic inflammatory disease characterized by chronic and relapsing manifestations. It is noteworthy that the prevalence of IBD is gradually increasing in both children and adults. Currently, the pathogenesis of IBD remains to be completely elucidated. IBD is believed to occur through interactions among genetics, environmental factors, and the gut microbiota. However, the relapsing and remitting course of IBD underlines the importance of other modifiers, such as psychological stress. Growing evidence from clinical and experimental studies suggests that stress acts as a promoting or relapsing factor for IBD. Importantly, recent studies have reported an increasing incidence of anxiety or depression in both children and adults with IBD. In this article, we review the mechanisms by which stress affects IBD, such as via impaired intestinal barrier function, disturbance of the gut microbiota, intestinal dysmotility, and immune and neuroendocrine dysfunction. With regard to both children and adults, we provide recent evidence to describe how stress can affect IBD at various stages. Furthermore, we emphasize the importance of mental healing and discuss the value of approaches targeting stress in clinical management to develop enhanced strategies for the prevention and treatment of IBD.

The stress concept in gastroenterology: from Selye to today

More than eighty years after Hans Selye (1907-1982) first developed a concept describing how different types of environmental stressors affect physiological functions and promote disease development (called the "general adaptation syndrome") in 1936, we herein review advances in theoretical, mechanistic, and clinical knowledge in stress research, especially in the area of gastroenterology, and summarize progress and future perspectives arising from an interdisciplinary psychoneurobiological framework in which genetics, epigenetics, and other advanced ( omics) technologies in the last decade continue to refine knowledge about how stress affects the brain-gut axis in health and gastrointestinal disease. We demonstrate that neurobiological stress research continues to be a driving force for scientific progress in gastroenterology and related clinical areas, inspiring translational research from animal models to clinical applications, while highlighting some areas that remain incompletely understood, such as the roles of sex/gender and gut microbiota in health and disease. Future directions of research should include not only the genetics of the stress response and resilience but also epigenetic contributions.

Chronic early life stress induced by limited bedding and nesting (LBN) material in rodents: critical considerations of methodology, outcomes and translational potential

The immediate and long-term effects of exposure to early life stress (ELS) have been documented in humans and animal models. Even relatively brief periods of stress during the first 10 days of life in rodents can impact later behavioral regulation and the vulnerability to develop adult pathologies, in particular an impairment of cognitive functions and neurogenesis, but also modified social, emotional, and conditioned fear responses. The development of preclinical models of ELS exposure allows the examination of mechanisms and testing of therapeutic approaches that are not possible in humans. Here, we describe limited bedding and nesting (LBN) procedures, with models that produce altered maternal behavior ranging from fragmentation of care to maltreatment of infants. The purpose of this paper is to discuss important issues related to the implementation of this chronic ELS procedure and to describe some of the most prominent endpoints and consequences, focusing on areas of convergence between laboratories. Effects on the hypothalamic-pituitary adrenal (HPA) axis, gut axis and metabolism are presented in addition to changes in cognitive and emotional functions. Interestingly, recent data have suggested a strong sex difference in some of the reported consequences of the LBN paradigm, with females being more resilient in general than males. As both the chronic and intermittent variants of the LBN procedure have profound consequences on the offspring with minimal external intervention from the investigator, this model is advantageous ecologically and has a large translational potential. In addition to the direct effect of ELS on neurodevelopmental outcomes, exposure to adverse early environments can also have intergenerational impacts on mental health and function in subsequent generation offspring. Thus, advancing our understanding of the effect of ELS on brain and behavioral development is of critical concern for the health and wellbeing of both the current population, and for generations to come.