Stress exposure, food intake and emotional state

Musclin prevents depression-like behavior in male mice by activating urocortin 2 signaling in the hypothalamus

Introduction

Physical activity is recommended as an alternative treatment for depression. Myokines, which are secreted from skeletal muscles during physical activity, play an important role in the skeletal muscle-brain axis. Musclin, a newly discovered myokine, exerts physical endurance, however, the effects of musclin on emotional behaviors, such as depression, have not been evaluated. This study aimed to access the anti-depressive effect of musclin and clarify the connection between depression-like behavior and hypothalamic neuropeptides in mice.

Methods

We measured the immobility time in the forced swim (FS) test, the time spent in open arm in the elevated-plus maze (EPM) test, the mRNA levels of hypothalamic neuropeptides, and enumerated the c-Fos-positive cells in the paraventricular nucleus (PVN), arcuate nucleus (ARC), and nucleus tractus solitarii (NTS) in mice with the intraperitoneal (i.p.) administration of musclin. Next, we evaluated the effects of a selective corticotropin-releasing factor (CRF) type 1 receptor antagonist, selective CRF type 2 receptor antagonist, melanocortin receptor (MCR) agonist, and selective melanocortin 4 receptor (MC4R) agonist on changes in behaviors induced by musclin. Finally we evaluated the antidepressant effect of musclin using mice exposed to repeated water immersion (WI) stress.

Results

We found that the i.p. and i.c.v. administration of musclin decreased the immobility time and relative time in the open arms (open %) in mice and increased urocortin 2 (Ucn 2) levels but decreased proopiomelanocortin levels in the hypothalamus. The numbers of c-Fos-positive cells were increased in the PVN and NTS but decreased in the ARC of mice with i.p. administration of musclin. The c-Fos-positive cells in the PVN were also found to be Ucn 2-positive. The antidepressant and anxiogenic effects of musclin were blocked by central administration of a CRF type 2 receptor antagonist and a melanocortin 4 receptor agonist, respectively. Peripheral administration of musclin also prevented depression-like behavior and the decrease in levels of hypothalamic Ucn 2 induced by repeated WI stress.

Discussion

These data identify the antidepressant effects of musclin through the activation of central Ucn 2 signaling and suggest that musclin and Ucn 2 can be new therapeutic targets and endogenous peptides mediating the muscle-brain axis.

Differences in segmental hair cortisol concentration analysis among children and adolescents with overweight and obesity, their parents, and normal weight peers

PURPOSE

Dysregulation of the stress system via incidental long exposure to glucocorticoids (GCs) can lead to weight gain. In addition, family and maternal stress can also have an impact on children's weight. Hair is used in several studies to evaluate cortisol (GC) levels in children and adolescents with excess weight as a retrospective stress biomarker, depending on the hair length the cortisol measurement depicting different time periods. We aimed to investigate whether there is a difference among segmental hair cortisol concentration (HCC) analysis between children and adolescents with overweight and obesity, their mothers, and normal weight peers.

METHODS

This study recruited 25 children aged 6-14 years with a body mass index (BMI) ≥ 85th centile and their mothers, as well as 20 children of the same age with a BMI < 85th centile. Hair cortisol concentration was measured using electrochemiluminescence immunoassay.

RESULTS

Segmental HCC analysis exhibited gradually decreasing values in all participants as segments of hair were more distantly located from the scalp. A positive correlation was found between BMI z-score and HCC of the first segment of hair in children and adolescents with elevated BMI (b = 1.84, p = 0.033), as well as with maternal HCC / of an only child (b = 15.77, p = 0.01). There were no associations between mother-child dyads and children and adolescents of different BMI groups, even though minors with excess weight exhibited higher HCC levels in all segments of hair in comparison to their normal weight counterparts.

CONCLUSIONS

Hair cortisol of all participants exhibited a gradually declining concentration. More studies with larger samples and more sensitive methods of analysis are warranted in order to draw firmer conclusions.

Dissecting the mediating and moderating effects of depression on the associations between traits and coronary artery disease: A two-step Mendelian randomization and phenome-wide interaction study

Background

Depression is often present concurrently with coronary artery disease (CAD), a disease with which it shares many risk factors. However, the manner in which depression mediates and moderates the association between traits (including biomarkers, anthropometric indicators, lifestyle behaviors, etc.) and CAD is largely unknown.

Methods

In our causal mediation analyses using two-step Mendelian randomization (MR), univariable MR was first used to investigate the causal effects of 108 traits on liability to depression and CAD. The traits with significant causal effects on both depression and CAD, but not causally modulated by depression, were selected for the second-step analyses. Multivariable MR was used to estimate the direct effects (independent of liability to depression) of these traits on CAD, and the indirect effects (mediated via liability to depression) were calculated. To investigate the moderating effect of depression on the association between 364 traits and CAD, a cross-sectional phenome-wide interaction study (PheWIS) was conducted in a study population from UK Biobank (UKBB) (N=275,257). Additionally, if the relationship between traits and CAD was moderated by both phenotypic and genetically predicted depression at a suggestive level of significance (Pinteraction≤0.05) in the PheWIS, the results were further verified by a cohort study using Cox proportional hazards regression.

Results

Univariable MR indicated that 10 of 108 traits under investigation were significantly associated with both depression and CAD, which showed a similar direct effect compared to the total effect for most traits. However, the traits "drive faster than speed limit" and "past tobacco smoking" were both exceptions, with the proportions mediated by depression at 24.6% and 7.2%, respectively. In the moderation analyses, suggestive evidence of several traits was found for moderating effects of phenotypic depression or susceptibility to depression, as estimated by polygenic risk score, including chest pain when hurrying, reason of smoking quitting and weight change. Consistent results were observed in survival analyses and Cox regression.

Conclusion

The independent role of traits in CAD pathogenesis regardless of depression was highlighted in our mediation analyses, and the moderating effects of depression observed in our study may be helpful for CAD risk stratification and optimized allocation of scarce medical resources.

Linking drug and food addiction: an overview of the shared neural circuits and behavioral phenotype

Despite a lack of agreement on its definition and inclusion as a specific diagnosable disturbance, the food addiction construct is supported by several neurobiological and behavioral clinical and preclinical findings. Recognizing food addiction is critical to understanding how and why it manifests. In this overview, we focused on those as follows: 1. the hyperpalatable food effects in food addiction development; 2. specific brain regions involved in both food and drug addiction; and 3. animal models highlighting commonalities between substance use disorders and food addiction. Although results collected through animal studies emerged from protocols differing in several ways, they clearly highlight commonalities in behavioral manifestations and neurobiological alterations between substance use disorders and food addiction characteristics. To develop improved food addiction models, this heterogeneity should be acknowledged and embraced so that research can systematically investigate the role of specific variables in the development of the different behavioral features of addiction-like behavior in preclinical models.

Physical exercise practice was positively associated with better dietary practices of aged people during COVID-19 social distance: A cross-sectional study

BACKGROUND & AIMS

COVID-19 is a respiratory syndrome caused by SARS-CoV-2. In the absence of effective treatment and vaccines, social distance (SD) is essential to reduce the spread of the virus. However, SD generates several behavioral changes, especially in psychological (i.e., emotions and depressive symptoms) and lifestyle-related parameters (i.e., diet, physical activity, and sleep), and the aged people could be more susceptible to COVID-19 SD-related effects (i.e., loneliness, stress, fear, concerns about life, etc.). As such, we aimed to explore the relationship between lifestyle- (physical exercise practice and sleep quality) and psychological-related factors with the dietary practices derived from the Brazilian National Food Guide of older adult during the COVID-19 SD.

METHODS

A web-based survey was conducted in São Paulo, Brazil. Data were collected between August and December 2020 (a period of social isolation due to the COVID-19 pandemic). The questions were extracted from validated questionnaires to verify dietary practices (score of adhesion to the food guide for the Brazilian population), sleep quality (by Pittsburgh questionnaire), emotional food-related dimensions (by Three-factor Eating Questionnaire), and depression symptoms (by Beck's questionnaire).

RESULTS

Results were from 229 aged people (mean age 66.5 ± 6.02 years old; mean BMI 27.5 ± 4.32 kg/m²; mean sleep duration 8.23 ± 1.41 h; Pittsburg sleep quality score 6.55 ± 4.83; dietary practice score 42.5 ± 6.47). In the adjusted-linear regression model, we verified that physical exercise practice at home (β = 2.179; 95% CI: 0.599 to 3.758; p = 0.007) during COVID-19 SD was positively associated with better dietary practices in aged people. In contrast, emotional eating was negatively associated with dietary practices (β = -0.051; 95% CI: -0.092 to - 0.009; p = 0.015).

CONCLUSION

We conclude that in aged people, physical exercise practice at home during COVID-19 SD was positively associated with better dietary practices, while emotional eating was negatively associated.

Changes in the Histological Structure of Adrenal Glands and Corticosterone Level after Whey Protein or Bee Pollen Supplementation in Running and Non-Running Rats

Due to the many health-promoting properties of bee pollen and whey protein, both products are widely used as dietary supplements. According to these reports on their health-promoting properties, the aim of our study is to assess whether these products can influence the structure and function of the adrenal glands in rats. Thirty male Wistar rats were divided into six equal groups. Among them, there were three groups which included non-running rats and three groups which included running rats. Both of these running (n = 3) and non-running (n = 3) groups included non-supplemented (control groups), bee-pollen-supplemented groups, and whey-protein-supplemented groups. After 8 weeks, the rats were decapitated, their adrenal glands were collected, and paraffin slides were prepared. Then, staining according to the standard H&E and Masson's trichrome protocols was performed. Fecal and urine samples were collected prior to the end of the study to measure corticosterone levels. In the group of non-running rats, the consumption of bee pollen was noted to be significantly higher when compared to the group of running rats (p < 0.05). The thickness of the particular adrenal cortex layers was similar among all of the groups (p > 0.05). The statistically significant changes in the microscopic structure of the adrenal glands, especially regarding cell nuclei diameter and structure, as well as the architecture of sinusoids, were observed between the groups. Moreover, urine corticosterone concentrations were found to vary between all of the analyzed groups (p < 0.05). These results indicate that both bee pollen and whey protein have limited stress-reducing potential.

Stress-driven potentiation of lateral hypothalamic synapses onto ventral tegmental area dopamine neurons causes increased consumption of palatable food

Stress can cause overconsumption of palatable high caloric food. Despite the important role of stress eating in obesity and (binge) eating disorders, its underlying neural mechanisms remain unclear. Here we demonstrate in mice that stress alters lateral hypothalamic area (LHA) control over the ventral tegmental area (VTA), thereby promoting overconsumption of palatable food. Specifically, we show that glutamatergic LHA neurons projecting to the VTA are activated by social stress, after which their synapses onto dopamine neurons are potentiated via AMPA receptor subunit alterations. We find that stress-driven strengthening of these specific synapses increases LHA control over dopamine output in key target areas like the prefrontal cortex. Finally, we demonstrate that while inducing LHA-VTA glutamatergic potentiation increases palatable fat intake, reducing stress-driven potentiation of this connection prevents such stress eating. Overall, this study provides insights in the neural circuit adaptations caused by stress that drive overconsumption of palatable food.

Leptin receptor co-expression gene network moderates the effect of early life adversity on eating behavior in children

Leptin influences eating behavior. Exposure to early adversity is associated with eating behaviour disorders and metabolic syndrome, but the role of the leptin receptor on this relationship is poorly explored. We investigated whether individual differences in brain region specific leptin receptor (LepR) gene networks could moderate the effects of early adversity on eating behavior and metabolism. We created an expression-based polygenic risk score (ePRS) reflecting variations in the function of LepR gene network in prefrontal cortex and hypothalamus to investigate the interactions between a cumulative index of postnatal adversity on eating behavior in two independent birth cohorts (MAVAN and GUSTO). To explore whether variations in the prefrontal cortex or hypothalamic genetic scores could be associated with metabolic measurements, we also assessed the relationship between LepR-ePRS and fasting blood glucose and leptin levels in a third independent cohort (ALSPAC). We identified significant interaction effects between postnatal adversity and prefrontal-based LepR-ePRS on the Child Eating Behavior Questionnaire scores. In MAVAN, we observed a significant interaction effect on food enjoyment at 48 months (β = 61.58, p = 0.015) and 72 months (β = 97.78, p = 0.001); food responsiveness at 48 months (β = 83.79, p = 0.009) satiety at 48 months (β = −43.63, p = 0.047). Similar results were observed in the GUSTO cohort, with a significant interaction effect on food enjoyment (β = 30.48, p = 0.006) food fussiness score (β = −24.07, p = 0.02) and satiety score at 60 months (β = −17.00, p = 0.037). No effects were found when focusing on the hypothalamus-based LepR-ePRS on eating behavior in MAVAN and GUSTO cohorts, and there was no effect of hypothalamus and prefrontal cortex based ePRSs on metabolic measures in ALSPAC. Our study indicated that exposure to postnatal adversity interacts with prefrontal cortex LepR-ePRS to moderate eating behavior, suggesting a neurobiological mechanism associated with the development of eating behavior problems in response to early adversity. The knowledge of these mechanisms may guide the understanding of eating patterns associated with risk for obesity in response to fluctuations in stress exposure early in life.

An expression-based polygenic risk score analysis of leptin receptor (LepR) genes suggests that LepR-specific genes co-expressed in the prefrontal cortex interact with exposure to postnatal adversity, potentially modulating eating behavior in children.

Food insecurity, diet quality, and suboptimal diabetes management among US adults with diabetes

INTRODUCTION

A healthy diet is recommended to support diabetes management, including HbA1c, blood pressure, and cholesterol (ABC) control, but food insecurity is a barrier to consuming a healthy diet. We determined the prevalence of food insecurity and diet quality among US adults with diabetes and the associations with ABC management.

RESEARCH DESIGN AND METHODS

Cross-sectional analyses were conducted among 2075 adults ≥20 years with diagnosed diabetes who participated in the 2013-2018 National Health and Nutrition Examination Surveys. Food insecurity was assessed using a standard questionnaire and diet quality was assessed using quartiles of the 2015 Healthy Eating Index. Adjusted ORs (aOR, 95% CI) were calculated from logistic regression models to determine the association between household food insecurity/diet quality and the ABCs while controlling for sociodemographic characteristics, healthcare utilization, smoking, medication for diabetes, blood pressure, or cholesterol, and body mass index.

RESULTS

Overall, 17.6% of adults had food insecurity/low diet quality; 14.2% had food insecurity/high diet quality; 33.1% had food security/low diet quality; and 35.2% had food security/high diet quality. Compared with adults with food security/high diet quality, those with food insecurity/low diet quality were significantly more likely to have HbA1c ≥7.0% (aOR=1.85, 95% CI 1.23 to 2.80) and HbA1c ≥8.0% (aOR=1.79, 95% CI 1.04 to 3.08); food insecurity/high diet quality was significantly associated with elevated HbA1c; and food security/low diet quality with elevated A1c.

CONCLUSIONS

Food insecurity, regardless of diet quality, was significantly associated with elevated A1c. For people with food insecurity, providing resources to reduce food insecurity could strengthen the overall approach to optimal diabetes management.

Interactions between central nervous system and peripheral metabolic organs

According to Descartes, minds and bodies are distinct kinds of "substance", and they cannot have causal interactions. However, in neuroscience, the two-way interaction between the brain and peripheral organs is an emerging field of research. Several lines of evidence highlight the importance of such interactions. For example, the peripheral metabolic systems are overwhelmingly regulated by the mind (brain), and anxiety and depression greatly affect the functioning of these systems. Also, psychological stress can cause a variety of physical symptoms, such as bone loss. Moreover, the gut microbiota appears to play a key role in neuropsychiatric and neurodegenerative diseases. Mechanistically, as the command center of the body, the brain can regulate our internal organs and glands through the autonomic nervous system and neuroendocrine system, although it is generally considered to be outside the realm of voluntary control. The autonomic nervous system itself can be further subdivided into the sympathetic and parasympathetic systems. The sympathetic division functions a bit like the accelerator pedal on a car, and the parasympathetic division functions as the brake. The high center of the autonomic nervous system and the neuroendocrine system is the hypothalamus, which contains several subnuclei that control several basic physiological functions, such as the digestion of food and regulation of body temperature. Also, numerous peripheral signals contribute to the regulation of brain functions. Gastrointestinal (GI) hormones, insulin, and leptin are transported into the brain, where they regulate innate behaviors such as feeding, and they are also involved in emotional and cognitive functions. The brain can recognize peripheral inflammatory cytokines and induce a transient syndrome called sick behavior (SB), characterized by fatigue, reduced physical and social activity, and cognitive impairment. In summary, knowledge of the biological basis of the interactions between the central nervous system and peripheral organs will promote the full understanding of how our body works and the rational treatment of disorders. Thus, we summarize current development in our understanding of five types of central-peripheral interactions, including neural control of adipose tissues, energy expenditure, bone metabolism, feeding involving the brain-gut axis and gut microbiota. These interactions are essential for maintaining vital bodily functions, which result in homeostasis, i.e., a natural balance in the body's systems.

Association and interaction of the MC4R rs17782313 polymorphism with plasma ghrelin, GLP-1, cortisol, food intake and eating behaviors in overweight/obese Iranian adults

BACKGROUND

Recent studies have shown that obesity is largely influenced by heredity and created by the interactions between several genes and environmental and behavioral factors. This study aimed to examine association between variant rs17782313 near melanocortin-4 receptor (MC4R) gene and behavioral and hormonal factors then evaluated interactions between variant MC4R rs17782313 with behavioral and hormonal factors on obesity.

METHODS

This cross-sectional study included 403 subjects, overweight and/or obesity, aged 20-50 years from Iran. The MC4R rs17782313 data were measured by the PCR-RFLP method. Dietary intake, physical activity, stress, anxiety, depression, appetite and emotional eating were assessed by using validated questionnaires. Ghrelin, glucagon-like peptide-1 and cortisol were measured by radioimmunoassay in plasma samples. Participants were also divided into three groups based on rs17782313 genotype and BMI.

RESULTS

After adjustment for age, gender, energy intake and PA, significant associations were observed between food intake, appetite, emotional eating, stress and physical activity with MC4R rs17782313 (p ˂0.05). Also, significant interactions were observed between fat intake (p-interaction = 0.002), protein intake (p-interaction = 0.01), energy intake (p-interaction = 0.01), emotional eating (p-interaction = 0.02), appetite (p-interaction = 0.04), stress (p-interaction = 0.04), ghrelin (p-interaction = 0.03), cortisol (p-interaction = 0.04) and physical activity (p-interaction = 0.04) and MC4R rs17782313 in terms of BMI.

CONCLUSION

Interactions between the CC genotype and high intakes of fat and energy, emotional eating, high appetite, and too much stress with high levels of cortisol and ghrelin probably can have an effect on BMI in overweight/obese subjects.

Prevalence of food addiction and its association with anxiety, depression, and adherence to social distancing measures in Brazilian university students during the COVID-19 pandemic: a nationwide study

The study's objective was to determine the prevalence of food addiction (FA) in Brazilian university students and to verify whether there is an association with anxiety, depression, and adherence to the social distancing measures adopted during the COVID-19 pandemic. This is a nationwide cross-sectional study carried out through the application of online questionnaires. Self-reported data on age, sex, economic class, race/skin color, anthropometric data, depression diagnosis, anxiety, modified Yale Food Addiction Scale 2.0 (mYFAS 2.0), and adherence to social distancing measures were collected. 5368 participants were included, with a mean age was 24.1 ± 6.3 years, the majority were female (n = 3990; 74.3%), and the mean BMI in our sample was 24.5 ± 5.3 kg/m². The prevalence of FA was 19.1% (95%CI: 18.0; 20.0%). An association was observed between FA with depression (PR: 1.60; 95%CI: 1.43; 1.78; p < 0.01), and anxiety (3.13; 95%CI: 2.74; 3.58; p < 0.01), but not with adherence to social distancing measures (p = 0.70). In conclusion, there was a higher prevalence of FA in Brazilian university students. Besides, university students with anxiety, depression, overweight, or obesity and females are more prone to FA.Level of evidence Level V, Opinions of authorities, based on descriptive studies, narrative reviews, clinical experience, or reports of expert committees.

Interactions between emotions and eating behaviors: Main issues, neuroimaging contributions, and innovative preventive or corrective strategies

Emotional eating is commonly defined as the tendency to (over)eat in response to emotion. Insofar as it involves the (over)consumption of high-calorie palatable foods, emotional eating is a maladaptive behavior that can lead to eating disorders, and ultimately to metabolic disorders and obesity. Emotional eating is associated with eating disorder subtypes and with abnormalities in emotion processing at a behavioral level. However, not enough is known about the neural pathways involved in both emotion processing and food intake. In this review, we provide an overview of recent neuroimaging studies, highlighting the brain correlates between emotions and eating behavior that may be involved in emotional eating. Interaction between neural and neuro-endocrine pathways (HPA axis) may be involved. In addition to behavioral interventions, there is a need for a holistic approach encompassing both neural and physiological levels to prevent emotional eating. Based on recent imaging, this review indicates that more attention should be paid to prefrontal areas, the insular and orbitofrontal cortices, and reward pathways, in addition to regions that play a major role in both the cognitive control of emotions and eating behavior. Identifying these brain regions could allow for neuromodulation interventions, including neurofeedback training, which deserves further investigation.

A High-Sugar Diet Consumption, Metabolism and Health Impacts with a Focus on the Development of Substance Use Disorder: A Narrative Review

Carbohydrates are important macronutrients in human and rodent diet patterns that play a key role in crucial metabolic pathways and provide the necessary energy for proper body functioning. Sugar homeostasis and intake require complex hormonal and nervous control to proper body energy balance. Added sugar in processed food results in metabolic, cardiovascular, and nervous disorders. Epidemiological reports have shown enhanced consumption of sweet products in children and adults, especially in reproductive age and in pregnant women, which can lead to the susceptibility of offspring’s health to diseases in early life or in adulthood and proneness to mental disorders. In this review, we discuss the impacts of high-sugar diet (HSD) or sugar intake during the perinatal and/or postnatal periods on neural and behavioural disturbances as well as on the development of substance use disorder (SUD). Since several emotional behavioural disturbances are recognized as predictors of SUD, we also present how HSD enhances impulsive behaviour, stress, anxiety and depression. Apart from the influence of HSD on these mood disturbances, added sugar can render food addiction. Both food and addictive substances change the sensitivity of the brain rewarding neurotransmission signalling. The results of the collected studies could be important in assessing sugar intake, especially via maternal dietary patterns, from the clinical perspective of SUD prevention or pre-existing emotional disorders. Methodology: This narrative review focuses on the roles of a high-sugar diet (HSD) and added sugar in foods and on the impacts of glucose and fructose on the development of substance use disorder (SUD) and on the behavioural predictors of drugs abuse. The literature was reviewed by two authors independently according to the topic of the review. We searched the PubMed and Scopus databases and Multidisciplinary Digital Publishing Institute open access scientific journals using the following keyword search strategy depending on the theme of the chapter: “high-sugar diet” OR “high-carbohydrate diet” OR “sugar” OR “glucose” OR “fructose” OR “added sugar” AND keywords. We excluded inaccessible or pay-walled articles, abstracts, conference papers, editorials, letters, commentary, and short notes. Reviews, experimental studies, and epidemiological data, published since 1990s, were searched and collected depending on the chapter structure. After the search, all duplicates are thrown out and full texts were read, and findings were rescreened. After the selection process, appropriate papers were included to present in this review.

Catalpol Exerts Antidepressant-Like Effects by Enhancing Anti-oxidation and Neurotrophy and Inhibiting Neuroinflammation via Activation of HO-1

Catalpol is an iridoid glycoside with rich content, rich nutrition, and numerous biological activities in Rehmanniae Radix contained in classic antidepressant prescriptions in Chinese clinical medicine. Catalpol has been confirmed previously its exact antidepressant-like effect involved heme oxygenase (HO)-1, but its antidepressant molecular targets and mechanism are still unclear. Here, catalpol's antidepressant-like molecular target was diagnosed and confirmed by ZnPP intervention [the antagonist of HO-1, (10 μg/rat), intracerebroventricular] for the first time, and its molecule mechanism network was determined through HO-1 related pathway and molecules in the hippocampus. Results showed that ZnPP significantly abolished catalpol's (10 mg/kg) reversal on depressive-like behaviors of chronic unpredictable mild stress rats, abolished catalpol's up-regulation on the phosphorylation level of extracellular regulated protein kinases (ERK)1/2 and brain-derived neurotrophic factor (BDNF)'s receptor tropomyosin-related kinase B (TrkB), the nuclear expression level of nuclear factor E 2-related factor 2 (Nrf2), the levels of anti-oxidant factors (such as HO-1, SOD, GPX, GST, GSH) and BDNF, and abolished catalpol's down-regulation on the levels of peroxide and neuroinflammation factors [cyclooxygenase-2 (COX-2), induced nitrogen monoxide synthase (iNOS), nitric oxide (NO)]. Thus, HO-1 could serve as an important potential molecular target for catalpol's antidepressant-like process, and the antidepressant-like mechanism of catalpol could at least involve the activation of HO-1 triggering the up-regulation of the ERK1/2/Nrf2/HO-1 pathway-related factors to enhance the anti-oxidant defense, triggering the down-regulation of the COX-2/iNOS/NO pathway-related factors to inhibit neuroinflammation, and triggering the up-regulation of the BDNF/TrkB pathway to enhance neurotrophy.

Association Between Perceived Levels of Stress and Self-Reported Food Preferences Among Males and Females: A Stated Preference Approach Based on the China Health and Nutrition Survey

Objective

Stress is a major public health challenge and is associated with undesirable eating behavior. This cross-sectional study aimed to explore whether there is an association between perceived level of stress and food preference among Chinese adults.

Study Design

Perceived level of stress was measured using the Chinese version of the 14-item Perceived Stress Scale, whereas self-reported food preferences were investigated by means of five food classification questions, including questions regarding the consumption of fast food, salty snacks, fruit, vegetables, and soft/sugary drinks.

Methods

The data were collected from the 2015 China Health and Nutrition Survey. Information of 8,216 adults (≥18 years) on perceived level of stress, self-reported food preferences, and other important covariates was available and analyzed.

Results

Perceived level of stress was negatively associated with a preference for fruit (β = −0.58, 95% CI: −0.81 to −0.34, p < 0.0001) and vegetables (β = −1.13, 95% CI: −1.41 to −0.85, p < 0.0001), while it was positively associated with a preference for fast food (β = 0.36, 95% CI: 0.08–0.64, p = 0.011) and soft/sugary drinks (β = 0.48, 95% CI: 0.30–0.66, p < 0.0001) after adjusting for potential confounders. No association between a preference for salty snacks and perceived level of stress was found in either men or women.

Conclusions

The present population-based study reported strong associations between perceived level of stress and self-reported food preferences among Chinese adults. Sex differences related to this association were also worthy of attention.

Psychological Impact of the Very Early Beginning of the COVID-19 Outbreak in Healthcare Workers: A Bayesian Study on the Italian and Swiss Perspectives

Background

We investigated the COVID19-related psychological impact on healthcare workers in Italy and in Italian-speaking regions of Switzerland, three weeks after its outbreak. All professional groups of public hospitals in Italy and Switzerland were asked to complete a 38 questions online survey investigating demographic, marital and working status, presence of stress symptoms and need for psychological support.

Results

Within 38 h a total of 3,038 responses were collected. The subgroup analysis identified specific categories at risk according to age, type of work and region of origin. Critical care workers, in particular females, reported an increased number of working hours, decline in confidence in the future, presence of stress symptoms and need for psychological support. Respondents reporting stress symptoms and those with children declared a higher need for psychological support.

Conclusions

The large number of participants in such a short time indicates for a high interest on topic among health-care workers. The COVID19 outbreak has been experienced as a repeated trauma for many health-care professionals, especially among female nurses' categories. Early evidence of the need of implementating short and long-term measures to mitigate impact of the emotional burden of COVID-19 pandemic are still relevant.

Association between lifestyle and emotional aspects of food consumption during the COVID-19 pandemic

BACKGROUND AND AIMS

Adequate nutrition during infectious outbreaks require a personal management strategy, especially when there are emotional factors involved. To evaluate the association between lifestyle and emotional aspects of food consumption during the pandemic COVID-19.

METHODS AND RESULTS

Cross-sectional study using online self-applied questionnaire with 15,372 active schoolteachers who worked in primary education (kindergarten, elementary and high school) from Minas Gerais, Brazil. Poisson Regression model with robust variance was used to determine the association between lifestyle and emotional aspects and food consumption. Greater adherence to the healthy consumption profile showed a statistically significant association with decreased weight (PR = 1.58; p = 0.000), decreased physical activity (PR = 1.27; p = 0.000), reduced income, (PR = 1.26; p = 0.000), reduced alcohol consumption (PR = 1.22; p = 0.000), and changes in mental health (PR = 1.19; p = 0.000). Unhealthy consumption profile was significantly correlated with weight gain (PR = 1.54; p = 0.000), consuming more alcohol, or started drinking during the pandemic (PR = 1.44; p = 0.000), increased physical activity (PR = 1.43; p = 0.000); increased cigarette consumption (PR = 1.17; p = 0.000), and being a younger adult (PR = 1.17; p = 0.000).

CONCLUSIONS

The COVID-19 pandemic influenced the food profiles of basic education teachers in the Minas Gerais state education system in a bidirectional manner, favoring the practice of consuming healthy or unhealthy foods.

A cross-species assay demonstrates that reward responsiveness is enduringly impacted by adverse, unpredictable early-life experiences

Exposure to early-life adversity (ELA) is associated with several neuropsychiatric conditions, including major depressive disorder, yet causality is difficult to establish in humans. Recent work in rodents has implicated impaired reward circuit signaling in anhedonic-like behavior after ELA exposure. Anhedonia, the lack of reactivity to previously rewarding stimuli, is a transdiagnostic construct common to mental illnesses associated with ELA. Here, we employed an assay of reward responsiveness validated across species, the Probabilistic Reward Task (PRT). In the PRT, healthy participants reliably develop a response bias toward the more richly rewarded stimulus, whereas participants with anhedonia exhibit a blunted response bias that correlates with current and future anhedonia. In a well-established model of ELA that generates a stressful, chaotic, and unpredictable early-life environment, ELA led to blunted response biases in the PRT in two separate cohorts, recapitulating findings in humans with anhedonia. The same ELA rats had blunted sucrose preference, further supporting their anhedonic-like phenotypes. Probing the aspects of ELA that might provoke these deficits, we quantified the unpredictability of dam/pup interactions using entropy measures and found that the unpredictability of maternal care was significantly higher in the ELA groups in which PRT and sucrose preference reward deficits were present later in life. Taken together, these data position the PRT, established in clinical patient populations, as a potent instrument to assess the impact of ELA on the reward circuit across species. These findings also implicate the unpredictability of maternal signals during early life as an important driver of reward sensitivity deficits.

Diet Prevents Social Stress-Induced Maladaptive Neurobehavioural and Gut Microbiota Changes in a Histamine-Dependent Manner

Exposure to repeated social stress may cause maladaptive emotional reactions that can be reduced by healthy nutritional supplementation. Histaminergic neurotransmission has a central role in orchestrating specific behavioural responses depending on the homeostatic state of a subject, but it remains to be established if it participates in the protective effects against the insults of chronic stress afforded by a healthy diet. By using C57BL/6J male mice that do not synthesize histamine (Hdc-/-) and their wild type (Hdc+/+) congeners we evaluated if the histaminergic system participates in the protective action of a diet enriched with polyunsaturated fatty acids and vitamin A on the deleterious effect of chronic stress. Behavioural tests across domains relevant to cognition and anxiety were performed. Hippocampal synaptic plasticity, cytokine expression, hippocampal fatty acids, oxylipins and microbiota composition were also assessed. Chronic stress induced social avoidance, poor recognition memory, affected hippocampal long-term potentiation, changed the microbiota profile, brain cytokines, fatty acid and oxylipins composition of both Hdc-/- and Hdc+/+ mice. Dietary enrichment counteracted stress-induced deficits only in Hdc+/+ mice as histamine deficiency prevented almost all the diet-related beneficial effects. Interpretation: Our results reveal a previously unexplored and novel role for brain histamine as a mediator of many favorable effects of the enriched diet. These data present long-reaching perspectives in the field of nutritional neuropsychopharmacology.

Stress-induced body weight loss and improvements in cardiometabolic risk factors do not translate to improved myocardial ischemic tolerance in western diet-fed mice

Although both diet-induced obesity and psychological stress are recognized as significant independent contributors to cardiometabolic and behavioral disorders, our understanding of how these two disorders interact and influence cardiometabolic risk and myocardial ischemic tolerance is limited. The aim of this study was to assess the combined effects of an obesogenic diet and psychological stress on cardiometabolic risk factors (body weight, dyslipidemia, insulin sensitivity) and postischemic cardiovascular outcomes. C57Bl/6J mice (n = 48) were subject to a combination of 22 weeks of western diet (WD) feeding and chronic restraint stress (CRS) for the last 4 weeks. Metabolic and behavioral changes were assessed using glucose tolerance tests and open field tests (OFTs), respectively. After 22 weeks, cardiac function and ischemic tolerance were assessed in Langendorff perfused hearts. WD feeding increased body weight and worsened blood lipids and insulin sensitivity. WD-fed mice also exhibited reduced exploratory behavior within the OFT. CRS reduced body weight and increased locomotion in both dietary groups and had differential effects on fasting glucose metabolism in the two dietary groups while not impacting non-fasting insulin. Although the WD only marginally reduced reperfusion left ventricular developed pressure recovery, CRS worsened reperfusion diastolic dysfunction in both dietary groups. Interestingly, despite WD+CRS animals exhibiting improved cardiometabolic parameters compared to the WD group, these changes did not translate to marked improvements to postischemic cardiac outcomes. In conclusion, in this study, combined WD feeding and CRS did not act synergistically to worsen cardiometabolic risk factors but instead improved them. Despite these cardiometabolic improvements, WD+CRS increased reperfusion end diastolic pressure which may be indicative of worsened ischemia/reperfusion injury.

Chrono-communication and cardiometabolic health: The intrinsic relationship and therapeutic nutritional promises

Circadian rhythm, an innate 24-h biological clock, regulates several mammalian physiological activities anticipating daily environmental variations and optimizing available energetic resources. The circadian machinery is a complex neuronal and endocrinological network primarily organized into a central clock, suprachiasmatic nucleus (SCN), and peripheral clocks. Several small molecules generate daily circadian fluctuations ensuring inter-organ communication and coordination between external stimuli, i.e., light, food, and exercise, and body metabolism. As an orchestra, this complex network can be out of tone. Circadian disruption is often associated with obesity development and, above all, with diabetes and cardiovascular disease onset. Moreover, accumulating data highlight a bidirectional relationship between circadian misalignment and cardiometabolic disease severity. Food intake abnormalities, especially timing and composition of meal, are crucial cause of circadian disruption, but evidence from preclinical and clinical studies has shown that food could represent a unique therapeutic approach to promote circadian resynchronization. In this review, we briefly summarize the structure of circadian system and discuss the role playing by different molecules [from leptin to ghrelin, incretins, fibroblast growth factor 21 (FGF-21), growth differentiation factor 15 (GDF15)] to guarantee circadian homeostasis. Based on the recent data, we discuss the innovative nutritional interventions aimed at circadian re-synchronization and, consequently, improvement of cardiometabolic health.

Effects of endocannabinoids on feed intake, stress response and whole-body energy metabolism in dairy cows

Endocannabinoids, particularly anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are instrumental in regulating energy homeostasis and stress response. However, little is known about the endocannabinoid system (ECS) in ruminants, although EC could improve dairy health and productivity, at least by increasing feed intake. In this study, we report if intraperitoneal (i.p.) AEA and 2-AG administration affects feed intake, whole-body macronutrient metabolism, isolation and restraint stress, and whether diet composition modulates circulating endocannabinoid concentrations in cows. Twenty Simmental cows in late lactation were fed a grass silage and a corn silage based diet. On each diet, cows received daily i.p. injections with either AEA (5 µg/kg; n = 7), 2-AG (2.5 µg/kg; n = 6) or saline (n = 7) for 8 days. Endocannabinoid administration for 5 days under free-ranging (non-stressed) conditions had no effect on feed intake or energy balance, but attenuated the stress-induced suppression of feed intake when housing changed to individual tie-stalls without social or tactile interaction. Endocannabinoids increased whole-body carbohydrate oxidation, reduced fat oxidation, and affected plasma non-esterified fatty acid concentrations and fatty acid contents of total lipids. There was no effect of endocannabinoids on plasma triglyceride concentrations or hepatic lipogenesis. Plasma AEA concentrations were not affected by diet, however, plasma 2-AG concentrations tended to be lower on the corn silage based diet. In conclusion, endocannabinoids attenuate stress-induced hypophagia, increase short-term feed intake and whole-body carbohydrate oxidation and decrease whole-body fat oxidation in cows.

Dietary Changes and Anxiety during the Coronavirus Pandemic: Differences between the Sexes

The SARS-CoV-2 (COVID-19) pandemic has been associated with both increased anxiety, deterioration in diet and weight gain. These associations may differ by sex. The present report examines differences by sex in diet quality in order to determine whether associations between diet and psychological stress during the initial phase of the COVID-19 pandemic differed by sex. This online study is available internationally in seven languages. The Mediterranean Diet Score was used to measure diet quality, while the General Anxiety Disorder 7-point scale (GAD-7) was used to measure anxiety. Findings were compared by self-reported sex (male vs. female). A total of 3797 respondents provided informed consent and met eligibility criteria, of whom 526 women were omitted due to being pregnant or six months or less post-partum, or due to reproductive status not being reported. Thus, 3271 individuals are included in the present report, of whom 71.2% were women. The median age of women was 30 (interquartile range (IQR) = 16) years vs. 31 (IQR = 19) years, p = 0.079. The median diet quality score was 9 (IQ = 3) in both women and men (p = 0.75). Despite the overall similarity in diet score, several components of the score differed significantly by sex. Women reported consuming significantly more olive oil, daily servings of vegetables, and weekly servings of sweet baked goods. Men reported consuming significantly more sweetened/carbonated drinks, red meat, alcohol, legumes, and hummus/tahini. Women reported a GAD-7 score of 6 (IQR = 8), while men reported 3 (6), p < 0.001. An inverse association was detected between the Mediterranean diet score and the GAD-7 score in both women (rho = −0.166, p < 0.001) and men (rho = −0.154, p < 0.001), and the correlation coefficients did not differ by sex (p = 0.76). Mediterranean diet score and age both reduced the odds of elevated anxiety (GAD-7 ≥ 10), while female sex, deterioration of diet quality during the outbreak, unemployment, and completing the survey in English increased the odds of this outcome. During the COVID-19 lockdowns, overall diet quality did not differ by sex; however, some differences by sex in components of the total score were detected. Moderate to severe anxiety was positively associated with female sex and poorer diet quality even after controlling for age, employment status, and the language in which the survey was performed.

Assessment of Spanish Food Consumption Patterns during COVID-19 Home Confinement

People's eating habits and lifestyle can have a negative impact on health. In situations of difficulty or socioeconomic crisis, these habits tend to be modified, leading to unhealthy dietary patterns that result in an increase of chronic non-communicable diseases (NCDs). Previous studies have indicated that, due to the state of alarm imposed in Spain to combat the spread of COVID-19, an increase in the purchase of non-core products occurred, along with a decrease in the daily physical activity of the population. This could be a risk factor for COVID-19 infection. The objective of this observational study was to analyze the dietary pattern of the Spanish population during home confinement and to compare it with the pattern of habitual consumption collected in the last National Health Survey, analyzing the possible changes. More than half of the respondents in the sample increased their consumption of sweets and snacks during confinement, while the consumption of fresh products decreased. Most claimed to be emotionally hungry, leading to an increase in their daily energy intake. The stress and anxiety generated by confinement could be the cause of the increased consumption of products rich in sugars and saturated fats, which are associated with greater stress and anxiety.

Does Modern Lifestyle Favor Neuroimmunometabolic Changes? A Path to Obesity

Factors linked to modern lifestyles, such as physical inactivity, Western diet, and poor sleep quality have been identified as key contributors to the positive energy balance (PEB). PEB rises adipose tissue hypertrophy and dysfunction over the years, affecting cells and tissues that are metabolically critical for energy homeostasis regulation, especially skeletal muscle, hypothalamic-pituitary-adrenal axis, and gut microbiota. It is known that the interaction among lifestyle factors and tissue metabolic dysfunction increases low-grade chronic systemic inflammation, leading to insulin resistance and other adverse metabolic disorders. Although immunometabolic mechanisms are widely discussed in obesity, neuroimmunoendocrine pathways have gained notoriety, as a link to neuroinflammation and central nervous system disorders. Hypothalamic inflammation has been associated with food intake dysregulation, which comprises homeostatic and non-homeostatic mechanisms, promoting eating behavior changes related to the obesity prevalence. The purpose of this review is to provide an updated and integrated perspective on the effects of Western diet, sleep debt, and physical exercise on the regulation of energy homeostasis and low-grade chronic systemic inflammation. Subsequently, we discuss the intersection between systemic inflammation and neuroinflammation and how it can contribute to energy imbalance, favoring obesity. Finally, we propose a model of interactions between systemic inflammation and neuroinflammation, providing new insights into preventive and therapeutic targets for obesity.

Adherence to Mediterranean Diet, Alcohol Consumption and Emotional Eating in Spanish University Students

(1) Introduction: The university period may increase the risk of different unhealthy habits, such as low adherence to the Mediterranean diet, high alcohol consumption and eating in response to specific emotions. The aim of this study was to detect early-risk alcohol consumption and alcohol dependence (ADS), the degree of adherence to the Mediterranean diet and emotional eating in university students of the Madrid community. (2) Methods: For each individual, anthropometric parameters, the Alcohol Use Disorders Identification Test (AUDIT), AUDIT-Consumption (AUDIT-C), the Mediterranean Diet Adherence Screener (MEDAS) and the Emotional Eater Questionnaire (EEQ) were assessed. (3) Results: A total of 584 university students aged 20.5 (sex ratio = 0.39) were enrolled in a cross-sectional study. In total, 63.6% of students showed low adherence to the Mediterranean diet, with no differences by sex (64.3% female versus 61.5% male, p = 0.19). According to the AUDIT questionnaire, 26.2% of participants were categorized as high-risk drinkers and 7.7% as ADS. About 38.6% of the students were categorized as eating very emotionally or eating emotionally, and 37.2% were categorized as low emotional eaters. A weak positive correlation was observed between the EEQ and BMI in female students (rho= 0.15, p = 0.03). (4) Conclusions: University students in our sample showed a low adherence to the Mediterranean diet, an important high-risk alcohol consumption and low emotional eating.

Impact of School Closures, Precipitated by COVID-19, on Weight and Weight-Related Risk Factors among Schoolteachers: A Cross-Sectional Study

The school closures, precipitated by the COVID-19 pandemic, required teachers to convert their entire classroom curricula to online formats, taught from home. This shift to a more sedentary teaching environment, coupled with the stresses related to the pandemic, may correlate with weight gain. In total, 52% of study participants reported weight gain, with a higher prevalence observed among kindergarten and elementary school teachers when compared to high school teachers (p < 0.05). Deviations in physical activity, emotional eating, and dietary patterns were assessed among 129 teachers (using the Leisure Time Exercise Questionnaire, the Dutch Eating Behavioral Questionnaire, and a short-form Food Frequency Questionnaire, respectively) to uncover possible associations with the observed weight gain. Increases in sedentariness (p < 0.005), emotional eating (p < 0.001), the consumption of potatoes, fries, breads, cheese, cake (p < 0.05), chips, candy, ice-cream, and soft drinks (p < 0.005) were all positively correlated with weight gain. Decreases in exercise frequency (p < 0.001), and the consumption of fruits (p < 0.05) and beans (p < 0.005), were also positively correlated with weight gain. Weight gain, observed among teachers during school closures, was associated with changes in diet, emotional eating and physical activity.

Unhealthy Food and Psychological Stress: The Association between Ultra-Processed Food Consumption and Perceived Stress in Working-Class Young Adults

BACKGROUND

Ultra-processed foods are industrial formulations made from food extracts or constituents with little or no intact food and often containing additives that confer hyper-palatability. The consumption of these products increases the risk of chronic non-communicable diseases. Stressed people may engage in unhealthy eating as a way to cope. This study aimed to verify whether ultra-processed food consumption was associated with perceived stress levels in industrial and retail workers from Vitoria da Conquista, Brazil.

METHODS

This was a cross-sectional study carried out between July 2017 and August 2018. During the study period, 1270 participants completed a survey administered by an interviewer. Stress levels were assessed using the Perceived Stress Scale. Information regarding weekly ultra-processed food consumption was collected. Ultra-processed foods were classified into four groups: sugary drinks; sugary foods; fast foods; and canned foods, frozen foods, or processed meat. The Student's t-test or one-way analysis of variance was used to assess the differences in stress levels and ultra-processed food consumption. Ordinal regression was used to determine the association between the degrees of stress and ultra-processed food consumption levels.

RESULTS

Factors such as a young age, being unmarried, smoking, high-risk alcohol consumption, negative health perception, and high perceived stress level indicated higher rates of ultra-processed food consumption. Ordinal regression analysis showed that high stress levels were associated with increased odds of higher ultra-processed food consumption (odds ratio: 1.94; 95% CI: 1.54-2.45).

CONCLUSIONS

These findings could help identify appropriate target areas for interventions aimed at mental health promotion and healthier food consumption.

Impact of adverse childhood experiences and fruit and vegetable intake in adulthood

OBJECTIVE

To assess the association between adverse childhood experiences (ACE) and behaviours of fruit and vegetable consumption among adults.

DESIGN

Cross-sectional analysis. Weighted χ2 and weighted multiple logistic regression analyses were conducted to determine the association between ACE and low fruit and vegetable consumption.

SETTING

The 2017 Nevada Behavioral Risk Factor Surveillance System.

PARTICIPANTS

The sample consisted of 2939 adults.

RESULTS

After controlling for potential confounders, exposure to three or more ACE (adjusted OR (AOR) 1·42, 95 % CI 1·02, 2·00) and experiencing parental divorce/separation (AOR 1·50, 95 % CI 1·13, 1·98) were significantly associated with low fruit and vegetable consumption. The study did not find a dose-response relationship between the number of ACE and fruit and vegetable consumption.

CONCLUSIONS

The study suggests that participants who experienced three or more ACE or parental divorce/separation were at increased risk for low fruit and vegetable consumption. The findings highlight the continuing need for public health interventions and policies that decrease exposure to ACE and increase fruit and vegetable intake among the populations with ACE.

Multinational dietary changes and anxiety during the coronavirus pandemic-findings from Israel

BACKGROUND

Increased anxiety was frequently reported during the 2020 global COVID-19 pandemic. An association between anxiety and increased body weight has been documented. Identifying associations between diet quality and anxiety may facilitate the development of preventive dietary policy, particularly relevant since obesity appears to increase the risk of adverse COVID-19 outcomes. In this study we aim to examine associations between changes in diet pattern and body weight and anxiety levels during the COVID-19 pandemic among Israeli respondents to an international online survey.

METHODS

Conducted between March 30-April 252,020, this was cross-sectional, international and online study. The questionnaire was developed and tested in Hebrew and translated into six other languages: English, Arabic, Spanish, French, Italian, and Russian. The survey was conducted on a Google Survey platform, the link to which was posted on several social media platforms. Adults aged 18 or older who saw and responded to the link on a social media site comprised the study population.

RESULTS

Of the 3979 eligible respondents, 1895 indicated their current location as Israel. Most Israeli respondents completed the survey in Hebrew (83.2%) followed by Arabic (9.4%), though responses were recorded in all seven of the survey languages. The median age was 33 (IQ = 22) years, and 75.7% were female. Almost 60% indicated that their pre-pandemic diet was healthier than their current diet, and 25.2% indicated they had gained weight during the pandemic. The median Mediterranean diet score was 9 (IQ = 3). While the median General Anxiety Disorder (GAD-7) score was 5 (IQ = 8), only 37.3% of participants reported at least mild anxiety (a GAD-7 score of 5 or more), while 10.7% reported moderate anxiety or greater (a GAD-7 score of 10 or more). In a multivariate logistic regression model of at least mild anxiety, being male and completing the survey in Hebrew significantly reduced odds of at least mild anxiety, while a worsening of diet quality during the pandemic, weight gain, and isolation significantly increased odds of at least mild anxiety.

CONCLUSIONS

During the COVID pandemic, changes in nutrition quality and habits were associated with greater anxiety. These findings suggest the need for routine and continuous surveillance of the nutritional and psychological consequences of outbreaks as part of healthcare preparedness efforts. Organizations responsible for community-based health services (such as Israeli health plans) should adopt specific interventions to improve case finding and support individuals at increased risk of anxiety and declining nutrition status within primary healthcare settings. These interventions should include the provision of appropriate diagnostic instruments, training of medical staff, feedback to physicians and nurses, and raising awareness among the relevant patient population and their caregivers. Primary care physicians should refer people with high anxiety or substantial weight gain during the pandemic to appropriate mental health and dietetic treatment, as needed.

TRIAL REGISTRATION

NCT04353934 .

Dietary changes and anxiety during the coronavirus pandemic: a multinational survey

Background/objectives

The 2020 global coronavirus pandemic is characterized by increased anxiety. Anxiety has been associated with poor diet quality and weight gain, which may lead to obesity, a risk factor for adverse COVID-19 outcomes. The present study was designed to examine associations between diet quality and anxiety levels during the COVID-19 pandemic.

Subjects/methods

This cross-sectional, international online study was conducted between March 30 and April 25, 2020 and available in seven languages: Arabic (7.6%), English (43.7%), French (0.8%), Hebrew (42.1%), Italian (3%), Russian (1.1%), and Spanish (1.6%). Diet quality was assessed using the Mediterranean Diet Score (possible range: 0–17 points) and anxiety scored using the General Anxiety Disorder 7-point scale (GAD-7). The Google Survey platform was used to conduct the survey.

Results

A total of 3797 persons were included in the present analysis. More than 75% of respondents were female; most completed the survey in English or Hebrew. Median age was 31 (IQ = 18) years. Almost 60% indicated that their pre-pandemic diet was healthier than their current diet. The median Mediterranean diet score was 9 (IQ = 3). The majority (54%) of participants reported at least mild anxiety, while 25% reported moderate anxiety or more severe. In a logistic regression model of at least moderate anxiety, Mediterranean diet score (OR 0.92, 95% CI 0.89–0.95, p < 0.0001) reduced odds of elevated anxiety, even after controlling for age, sex and other variables.

Conclusions

Though causality cannot be inferred, associations between diet quality and anxiety might suggest public health interventions including diet and stress control during future mass lockdowns.

The Impact of Chronic Stress and Eating Concern on Acylated Ghrelin Following Acute Psychological Stress in Healthy Men

Stress, mood, and eating behavior play an important role in appetite and weight regulation. In particular, ghrelin, as the only known orexigenic hormone, has been suggested to be an influential mediator in food intake responses to stress. The exact role of ghrelin in the hypothalamic–pituitary–adrenal axis is still unknown and further challenged by the psychological aspects of stress and eating behavior. This study aimed to assess the effect of chronic stress and subjective concern about eating on acute stress-induced changes in acylated ghrelin. In a 2-day study, sixteen healthy male participants were confronted with a stressful situation as well as a control situation. Additional measurements of heart rate, subjective hunger ratings, and subjective mood ratings were made to assess successful acute stress induction. The linear mixed model approach revealed a significant effect of acute stress on acylated ghrelin for a study-day*chronic-stress interaction (p < 0.001). Concern about eating did not affect acylated ghrelin levels after acute stress exposure. The significant interaction showed that lower chronic stress exposure was associated with a stronger acylated ghrelin response after acute stress exposure versus control condition. At the same time, participants with higher chronic stress exposure showed a blunted acylated ghrelin response after acute stress exposure compared to the control situation. Our findings indicate that chronic stress exposure can influence acylated ghrelin response after acute stress encounters, possibly affecting subsequent food intake and explaining the often diverse outcome in measurements of acute stress responses.

Glucagon-Like Peptide-1 (GLP-1) in the Integration of Neural and Endocrine Responses to Stress

Glucagon like-peptide 1 (GLP-1) within the brain is produced by a population of preproglucagon neurons located in the caudal nucleus of the solitary tract. These neurons project to the hypothalamus and another forebrain, hindbrain, and mesolimbic brain areas control the autonomic function, feeding, and the motivation to feed or regulate the stress response and the hypothalamic-pituitary-adrenal axis. GLP-1 receptor (GLP-1R) controls both food intake and feeding behavior (hunger-driven feeding, the hedonic value of food, and food motivation). The activation of GLP-1 receptors involves second messenger pathways and ionic events in the autonomic nervous system, which are very relevant to explain the essential central actions of GLP-1 as neuromodulator coordinating food intake in response to a physiological and stress-related stimulus to maintain homeostasis. Alterations in GLP-1 signaling associated with obesity or chronic stress induce the dysregulation of eating behavior. This review summarized the experimental shreds of evidence from studies using GLP-1R agonists to describe the neural and endocrine integration of stress responses and feeding behavior.

Bigger doesn't mean bolder: behavioral variation of four wild rodent species to novelty and predation risk following a fast-slow continuum

Background

Understanding how wild species respond to novel situations with associated risk can provide valuable insights for inter-specific behavioral variation and associations with pace-of-life (POL). Rodents, a globally distributed and diverse taxonomic group, have been the subjects of countless studies emulating risky situations. Controlled laboratory experiments with a focus on wild-caught species provide the opportunity to test fine-scale behavioral responses to contexts of risk with ecological implications. For example, assessing the importance of predator cues eliciting antipredator responses, as well as whether wild rodents embody behavioral plasticity and repertoires, illustrated by habituation and variation in behavioral traits, respectively.

Results

In this comparative study, we examined multiple behavioral responses of four rodent species in eastern Taiwan (three native species Mus caroli, Apodemus agrarius, Rattus losea, and one invasive, Rattus exulans) exposed to an unfamiliar microenvironment and novel cue from an allopatric predator, the leopard cat (Prionailurus bengalensis). All wild-caught animals were subjected to two consecutive nights of experimental trials in a laboratory setting. Behavioral responses to a novel situation during the first trial differed between species; smaller species investing more time in non-defensive behaviors compared to the larger species. More specifically, the smaller species M. caroli and A. agrarius allocated more time to exploration and foraging, whereas the larger rat species R. exulans and R. losea spent more time motionless or concealing. During the second trial, the addition of leopard cat cues did not elicit antipredator behaviors, but rather, rodents were found to exhibit increased non-defensive behaviors, specifically foraging efforts.

Conclusions

Our results suggest that these four species do largely follow a behavioral fast-slow continuum with the two smaller mice species demonstrating increased boldness in a novel context compared to the larger rat species. Also, the wild populations of rodents in eastern Taiwan may be naïve to leopard cats. Finally, the rodents in our study demonstrated habituation to the microenvironment, indicating they possess adaptive capacity.

A Humanities-Based Explanation for the Effects of Emotional Eating and Perceived Stress on Food Choice Motives during the COVID-19 Pandemic

Perceived stress affects emotional eating and food choices. However, the extent to which stress associates with food choice motives is not completely understood. This study assessed whether emotional eating mediates the associations between perceived stress levels and food choice motives (i.e., health, mood, convenience, natural content, price, sensory appeal, familiarities, weight control, and ethical concerns) during the Coronavirus Disease 2019 pandemic. A total of 800 respondents were surveyed in the United States in June 2020. Their perceived stress, emotional eating, and food choice motives were assessed by the Perceived Stress Scale, Dutch Eating Behavior Questionnaire, and Food Choice Questionnaire, respectively. Moderate to high levels of perceived stress were experienced by the majority (73.6%) of respondents. Perceived stress was significantly correlated with emotional eating (r = 0.26) as well as five out of nine food choice motives: mood (r = 0.32), convenience (r = 0.28), natural content (r = −0.14), price (r = 0.27), and familiarity (r = 0.15). Emotional eating was significantly correlated with four out of nine food choice motives: mood (r = 0.27), convenience (r = 0.23), price (r = 0.16), and familiarity (r = 0.16). The mediation analyses showed that emotional eating mediates the associations between perceived stress and five food choices motives: mood, convenience, sensory appeal, price, and familiarity. Findings were interpreted using theories and concepts from the humanities, specifically, folklore studies, ritual studies, and symbolic anthropology.

GABAergic System in Stress: Implications of GABAergic Neuron Subpopulations and the Gut-Vagus-Brain Pathway

Stress can cause a variety of central nervous system disorders, which are critically mediated by the γ-aminobutyric acid (GABA) system in various brain structures. GABAergic neurons have different subsets, some of which coexpress certain neuropeptides that can be found in the digestive system. Accumulating evidence demonstrates that the gut-brain axis, which is primarily regulated by the vagus nerve, is involved in stress, suggesting a communication between the "gut-vagus-brain" pathway and the GABAergic neuronal system. Here, we first summarize the evidence that the GABAergic system plays an essential role in stress responses. In addition, we review the effects of stress on different brain regions and GABAergic neuron subpopulations, including somatostatin, parvalbumin, ionotropic serotonin receptor 5-HT3a, cholecystokinin, neuropeptide Y, and vasoactive intestinal peptide, with regard to signaling events, behavioral changes, and pathobiology of neuropsychiatric diseases. Finally, we discuss the gut-brain bidirectional communications and the connection of the GABAergic system and the gut-vagus-brain pathway.

Psychosociocultural Contributors to Maladaptive Eating Behaviors in African American Youth: Recommendations and Future Directions

Childhood overweight and obesity disproportionately affects African Americans, and these children benefit less from standard pediatric weight management treatment programs compared to other racial/ethnic groups. Maladaptive eating behavior has been identified as a behavioral contributor to obesity and is also associated with the development of nonrestrictive eating disorders over time. Unique psychosociocultural factors have been identified that may promote higher risk for maladaptive eating behaviors in African American children beyond the effects of economic disparity. To best treat this group, it is important for practitioners to have a thorough understanding of these factors. We review several of these considerations and describe ways they may interact to contribute to the subsequent development of maladaptive eating behaviors and increased weight. Recommendations are made regarding how attention to these factors could be incorporated into current pediatric weight management treatments to better serve this population via a patient-centered care approach. Future directions will also be discussed.

PPG neurons in the nucleus of the solitary tract modulate heart rate but do not mediate GLP-1 receptor agonist-induced tachycardia in mice

Objective

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are used as anti-diabetic drugs and are approved for obesity treatment. However, GLP-1RAs also affect heart rate (HR) and arterial blood pressure (ABP) in rodents and humans. Although the activation of GLP-1 receptors (GLP-1R) is known to increase HR, the circuits recruited are unclear, and in particular, it is unknown whether GLP-1RAs activate preproglucagon (PPG) neurons, the brain source of GLP-1, to elicit these effects.

Methods

We investigated the effect of GLP-1RAs on heart rate in anaesthetized adult mice. In a separate study, we manipulated the activity of nucleus tractus solitarius (NTS) PPG neurons (PPG^NTS) in awake, freely behaving transgenic Glu-Cre mice implanted with biotelemetry probes and injected with AAV-DIO-hM3Dq:mCherry or AAV-mCherry-FLEX-DTA.

Results

Systemic administration of the GLP-1RA Ex-4 increased resting HR in anaesthetized or conscious mice, but had no effect on ABP in conscious mice. This effect was abolished by β-adrenoceptor blockade with atenolol, but unaffected by the muscarinic antagonist atropine. Furthermore, Ex-4-induced tachycardia persisted when PPG^NTS neurons were ablated, and Ex-4 did not induce expression of the neuronal activity marker cFos in PPG^NTS neurons. PPG^NTS ablation or acute chemogenetic inhibition of these neurons via hM4Di receptors had no effect on resting HR. In contrast, chemogenetic activation of PPG^NTS neurons increased resting HR. Furthermore, the application of GLP-1 within the subarachnoid space of the middle thoracic spinal cord, a major projection target of PPG neurons, increased HR.

Conclusions

These results demonstrate that both systemic application of Ex-4 or GLP-1 and chemogenetic activation of PPG^NTS neurons increases HR. Ex-4 increases the activity of cardiac sympathetic preganglionic neurons of the spinal cord without recruitment of PPG^NTS neurons, and thus likely recapitulates the physiological effects of PPG neuron activation. These neurons therefore do not play a significant role in controlling resting HR and ABP but are capable of inducing tachycardia and so are likely involved in cardiovascular responses to acute stress.

•

Activation of PPG neurons triggers increases in heart rate in mice.

•

PPG neurons do not provide a tonic sympathetic drive to the heart.

•

The tachycardic effect of systemic Ex-4 is not mediated by PPG neurons.

•

GLP-1 receptor activation has a sympathoexcitatory effect that increases heart rate.

•

Local activation of GLP-1R in the spinal cord is sufficient to elicit tachycardia.

Thirty-two weeks of randomized interdisciplinary therapy or combined physical training promote similar improvements in anthropometric and biochemical parameters of obese women

BACKGROUND

Obesity is a multicausal illness that generates large expenses to health systems and also for the families of obese individuals. It is important to note that obesity disrupts all systems, generating metabolic consequences that may be irreversible. Interdisciplinary therapy is recommended as the primary method for treating obesity. However, the cost of interdisciplinary treatment can be high due to the need for various professionals, from different areas of expertise. This study compares the effects of 32 weeks of physical training combined with interdisciplinary therapy on anthropometric and biochemical parameters in obese women.

METHODS

Seventy-six subjects were randomized into two groups: Group Physical Exercise (EXE) and Group Interdisciplinary Treatment (INTER), being evaluated in the initial moment and after 32 weeks. 30 subjects completed the intervention and were evaluated (EXE: N.=13; INTER: N.=17).

RESULTS

Psychobiological and biochemical variables were measured. EXE and INTER were similar before treatment and both showed significantly improvements in anthropometric and biochemical parameters after interventions, without difference between groups.

CONCLUSIONS

The results confirmed the relevant role of physical training or the interdisciplinary therapy on metabolic profile of obese women. We realized that physical training can be incorporated into public or private health systems as an alternative strategy for obesity control, especially in locations that do not have the possibility of offering a complete interdisciplinary therapy.

Effect of nutritive and non-nutritive sweeteners on hemodynamic responses to acute stress: a randomized crossover trial in healthy women

Background

The mechanisms by which chronic stress increases the risk of non-communicable diseases remain poorly understood. On one hand, chronic stress may increase systemic vascular resistance (SVR) and blood pressure, which may lead to blood vessels injury and altered myocardial perfusion. On the other hand, chronic stress may promote the overconsumption of sugar-containing foods and favor obesity. There is indeed evidence that sweet foods are preferentially consumed to alleviate stress responses. The effects of nutritive and non-nutritive sweeteners (NNS) on hemodynamic stress responses remain however largely unknown.

Objective/design

This study aimed at comparing the effects of sucrose-containing and NNS-containing drinks, as compared to unsweetened water, on hemodynamic responses to acute stress in twelve healthy female subjects. Acute stress responses were elicited by a 30-min mental stress (5-min Stroop’s test alternated with 5-min mental arithmetic) and a 3-min cold pressure test (CPT), each preceded by a resting baseline period. Hemodynamic stress responses were investigated by the repeated measurement of mean arterial pressure and the continuous monitoring of cardiac output by thoracic electrical bioimpedance measurement. SVR was selected as a primary outcome because it is a sensitive measure of hemodynamic responses to acute stress procedures.

Results

With all three drinks, SVR were not changed with mental stress (P = 0.437), but were increased with CPT (P = 0.045). Both mental stress and CPT increased mean arterial pressure and heart rate (all P < 0.001). Cardiac output increased with mental stress (P < 0.001) and remained unchanged with CPT (P = 0.252). No significant differences in hemodynamic responses were observed between water, sucrose and NNS (stress × condition, all P > 0.05).

Conclusions

These results demonstrate that sucrose and NNS do not alter hemodynamic responses to two different standardized acute stress protocols.

COVID-19 Related Distress Is Associated With Alcohol Problems, Social Media and Food Addiction Symptoms: Insights From the Italian Experience During the Lockdown

Background: Several scholars hypothesize that one of the most negative impacts of the coronavirus disease 2019 (COVID-19) crisis would concern the increase of prevalence and severity of both substances and behavioral addiction. Despite the general concerns about the increase of prevalence and severity of addictions related to the COVID-19 emergency, few data are still available. Thus, the main aim of this study was to investigate the association between COVID-19 related distress and: (i) alcohol problems, (ii) social media addiction (SMA) symptoms, (iii) food addiction (FA) symptoms. Methods: A national online-survey was carried out during the Italian lockdown (i.e., 9 March 2020-4 May 2020). In the current study, 1,519 participants (365 men and 1,154 women, mean age: 28.49 ± 10.89 years) were included. The survey included socio-demographic related items (e.g., age, sex, residential regions, education level, civil status, tobacco use, etc.), as well as ad-hoc developed questions aimed to investigate COVID-19 related variables (e.g., isolation/quarantine, personal diagnosis to COVID-19, friends or relatives with COVID-19 diagnosis, etc.). Participants also completed the following self-report measures in order to investigate: the psychological impact of COVID-19, alcohol problems, SMA symptoms, FA symptoms, and impulsivity. Results: The psychological impact of COVID-19 was independently associated with alcohol problems (β = 0.058, p = 0.043), SMA symptoms (β = 0.259, p < 0.001), and FA symptoms (β = 0.150, p < 0.001). Conclusion: Taken together, our results seem to confirm the general concerns about the negative impacts of the COVID-19 emergency on addictive behaviors, suggesting that this issue should be carefully monitored.

Stress, Dietary Patterns and Cardiovascular Disease: A Mini-Review

According to the World Health Organization, an unhealthy diet and insufficient physical activity are the leading global risks to health. Dietary behavior is a modifiable factor in cardiovascular disease (CVD) prevention. Furthermore, the fact that cardiovascular events and stress-related emotional disorders share a common epidemiology may indicate the existence of pathways linking these two diseases (Chauvet-Gelinier and Bonin, 2017). Psychosocial stress can lead to changes in dietary patterns (DP) and under chronic stress conditions, high caloric and hyperpalatable foods are preferred. The interplay between these two factors impacts on several biological pathways: for example, it can prime the hippocampus to produce a potentiated neuroinflammatory response, generating memory deficits; it can also affect gut microbiota composition, ultimately influencing behavior and brain health and creating a predisposition to the development of diseases such as obesity, CVD, diabetes and metabolic syndrome. Though both cognition and emotion can be heavily affected by caloric intake, diet composition and stress, the molecular pathways involved remain elusive (Spencer et al., 2017). In this review, we describe the interplay between stress and DP at a molecular level, and how these factors relate to brain health and mental fitness. Finally, we show how these findings could give rise to novel therapeutic targets for chronic diseases.

Animal models of major depression: drawbacks and challenges

Major depression is a leading contributor to the global burden of disease. This situation is mainly related to the chronicity and/or recurrence of the disorder, and to poor response to antidepressant therapy. Progress in this area requires valid animal models. Current models are based either on manipulating the environment to which rodents are exposed (during the developmental period or adulthood) or biological underpinnings (i.e. gene deletion or overexpression of candidate genes, targeted lesions of brain areas, optogenetic control of specific neuronal populations, etc.). These manipulations can alter specific behavioural and biological outcomes that can be related to different symptomatic and pathophysiological dimensions of major depression. However, animal models of major depression display substantial shortcomings that contribute to the lack of innovative pharmacological approaches in recent decades and which hamper our capabilities to investigate treatment-resistant depression. Here, we discuss the validity of these models, review putative models of treatment-resistant depression, major depression subtypes and recurrent depression. Furthermore, we identify future challenges regarding new paradigms such as those proposing dimensional rather than categorical approaches to depression.

Stress and Food Consumption Relationship in Hypertensive Patients

BACKGROUND

Stress is a state of threat to the balance of the organism, which can cause biological and psychological changes. In hypertensive patients, stress can interfere with blood pressure levels, influence on food choices and neglect of the diet.

OBJECTIVE

This study aims to describe the relationship between stress and dietary intake of hypertensive patients.

METHODS

A transversal study was carried out at the Arterial Hypertension Clinic of the Cardiology Institute of Rio Grande do Sul, Brazil. The participants were aged ≥ 18 years and hypertensive. Blood pressure, food consumption and anthropometric measurements were collected. The variables related to stress were evaluated by the Lipp's Stress Symptoms Inventory (LSSI) for adults. Significance level of 5% has been considered for all analyzed data.

RESULTS

The number of participants was 100. There was a higher prevalence of the female sex (67%), the mean age of the study population was 55.87 ± 12.55 years. Among the participants, 86% were classified in some of the stress phases, on which 57% were in the resistance phase. It was observed that there was no correlation between the presence of stress (as well as their actions), pressure levels and food consumption. The consumption of foods rich in lipids and individuals with a prevalence of psychological symptoms of stress displayed a significant association.

CONCLUSIONS

Rich in fat dietary has been the first choice in patients with psychological symptoms of stress. Further studies regarding remodeled dietary intake and blood pressure levels in relation to the stress phases are suggested. These findings are important to contribute to the development of prevention and treatment strategies for cardiovascular diseases.

Oral supplementation with ginseng polysaccharide promotes food intake in mice

INTRODUCTION

Ginseng polysaccharide (GPS, same as Panax polysaccharide) is a kind of polysaccharide extracted from ginseng. It has been reported that GPS has the ability to activate innate immunity, regulates blood sugar balance, and improves antioxidant capacity, but the effect on feeding behavior and its mechanism remains unclear.

METHOD

To investigate the possible effect of GPS on feeding behavior of animals, mice were supplied with GPS in water, and food intake, hedonic feeding behavior, anxiety-like behavior, expression of appetite-regulation peptides in the central nervous system and glucose-related hormone levels in the serum of mice were measured.

RESULTS

Ginseng polysaccharide significantly increased the average daily food intake in mice and promoted hedonic eating behavior. Meanwhile, the levels of serum glucose and glucagon were significantly reduced by GPS, and GPS promoted hypothalamic neuropeptide Y expression, inhibited proopiomelanocortin (POMC) expression, and reduced dopamine D1 receptor (DRD1) levels in the midbrain. We also found that the anxiety level of mice was significantly lower after GPS intake. In conclusion, oral supplementation with GPS promoted food intake in mice, most likely through the regulation of circulating glucose levels.

Secretin Regulates Excitatory GABAergic Neurotransmission to GnRH Neurons via Retrograde NO Signaling Pathway in Mice

In mammals, reproduction is regulated by a wide range of metabolic hormones that maintain the proper energy balance. In addition to regulating feeding and energy expenditure, these metabolic messengers also modulate the functional performance of the hypothalamic-pituitary-gonadal (HPG) axis. Secretin, a member of the secretin-glucagon-vasoactive intestinal peptide hormone family, has been shown to alter reproduction centrally, although the underlying mechanisms have not been explored yet. In order to elucidate its central action in the neuroendocrine regulation of reproduction, in vitro electrophysiological slice experiments were carried out on GnRH-GFP neurons in male mice. Bath application of secretin (100 nM) significantly increased the frequency of the spontaneous postsynaptic currents (sPSCs) to 118.0 ± 2.64% compared to the control, and that of the GABAergic miniature postsynaptic currents (mPSCs) to 147.6 ± 19.19%. Resting membrane potential became depolarized by 12.74 ± 4.539 mV after secretin treatment. Frequency of evoked action potentials (APs) also increased to 144.3 ± 10.8%. The secretin-triggered elevation of the frequency of mPSCs was prevented by using either a secretin receptor antagonist (3 μM) or intracellularly applied G-protein-coupled receptor blocker (GDP-β-S; 2 mM) supporting the involvement of secretin receptor in the process. Regarding the actions downstream to secretin receptor, intracellular blockade of protein kinase A (PKA) with KT-5720 (2 μM) or intracellular inhibition of the neuronal nitric oxide synthase (nNOS) by NPLA (1 μM) abolished the stimulatory effect of secretin on mPSCs. These data suggest that secretin acts on GnRH neurons via secretin receptors whose activation triggers the cAMP/PKA/nNOS signaling pathway resulting in nitric oxide release and in the presynaptic terminals this retrograde NO machinery regulates the GABAergic input to GnRH neurons.

Stressing the importance of choice: Validity of a preclinical free-choice high-caloric diet paradigm to model behavioural, physiological and molecular adaptations during human diet-induced obesity and metabolic dysfunction

Humans have engineered a dietary environment that has driven the global prevalence of obesity and several other chronic metabolic diseases to pandemic levels. To prevent or treat obesity and associated comorbidities, it is crucial that we understand how our dietary environment, especially in combination with a sedentary lifestyle and/or daily-life stress, can dysregulate energy balance and promote the development of an obese state. Substantial mechanistic insight into the maladaptive adaptations underlying caloric overconsumption and excessive weight gain has been gained by analysing brains from rodents that were eating prefabricated nutritionally-complete pellets of high-fat diet (HFD). Although long-term consumption of HFDs induces chronic metabolic diseases, including obesity, they do not model several important characteristics of the modern-day human diet. For example, prefabricated HFDs ignore the (effects of) caloric consumption from a fluid source, do not appear to model the complex interplay in humans between stress and preference for palatable foods, and, importantly, lack any aspect of choice. Therefore, our laboratory uses an obesogenic free-choice high-fat high-sucrose (fc-HFHS) diet paradigm that provides rodents with the opportunity to choose from several diet components, varying in palatability, fluidity, texture, form and nutritive content. Here, we review recent advances in our understanding how the fc-HFHS diet disrupts peripheral metabolic processes and produces adaptations in brain circuitries that govern homeostatic and hedonic components of energy balance. Current insight suggests that the fc-HFHS diet has good construct and face validity to model human diet-induced chronic metabolic diseases, including obesity, because it combines the effects of food palatability and energy density with the stimulating effects of variety and choice. We also highlight how behavioural, physiological and molecular adaptations might differ from those induced by prefabricated HFDs that lack an element of choice. Finally, the advantages and disadvantages of using the fc-HFHS diet for preclinical studies are discussed.

Enhanced anxiety-like behavior emerges with weight gain in male and female obesity-susceptible rats

Epidemiological data suggest that body mass index and obesity are strong risk factors for depression and anxiety. However, it is difficult to separate cause from effect, as predisposition to obesity may enhance susceptibility to anxiety, or vice versa. Here, we examined the effect of diet and obesity on anxiety-like behaviors in male and female selectively bred obesity-prone and obesity-resistant rats, and outbred Sprague-Dawley rats. We found that when obesity-prone and obesity-resistant rats do not differ in weight or fat mass, measures of anxiety-like behavior in the elevated plus maze and open field are similar between the two groups. However, once weight and fat mass diverge, group differences emerge, with greater anxiety in obesity-prone relative to obesity-resistant rats. This same pattern was observed for males and females. Interestingly, even when obesity-resistant rats were "forced" to gain fat mass comparable to obesity-prone rats (via prolonged access to 60% high-fat diet), anxiety-like behaviors did not differ from lean chow fed controls. In addition, a positive correlation between anxiety-like behaviors and adiposity were observed in male but not in female obesity-prone rats. Finally, diet-induced weight gain in and of itself was not sufficient to increase measures of anxiety in outbred male rats. Together, these data suggest that interactions between susceptibility to obesity and physiological alterations accompanying weight gain may contribute to the development of enhanced anxiety.