CRH-stimulated cortisol release and food intake in healthy, non-obese adults

A Review of the Literature on Wellbeing and Modifiable Dementia Risk Factors

Wellbeing-defined broadly as experiencing one's life as enjoyable and fulfilling-has been associated with lower risk for Alzheimer's disease and related dementias. The mechanisms underlying this association are largely unknown. However, prior research and theory suggest that wellbeing impacts health behaviors and biological systems that are relevant to cognitive and brain health. Several of these factors have also been identified by the 2020 Lancet Commission on Dementia Prevention, Intervention, and Care as modifiable dementia risk factors. In the current review, we summarize and evaluate the evidence for associations between wellbeing and each of the 12 Lancet Commission risk factors. We found relatively consistent evidence for associations between higher wellbeing and lower levels of most of the risk factors: physical inactivity, social isolation, smoking, depression, hypertension, diabetes, hearing loss, traumatic brain injury, and air pollution. By contrast, we found evidence for only modest associations between wellbeing and education and mixed evidence for associations of wellbeing with alcohol use and body weight. Although most of the reviewed evidence was observational, longitudinal and experimental evidence suggests that many of the observed associations are likely bidirectional. These findings suggest that modifiable dementia risk factors may be mediators (i.e., intermediate steps in the causal chain) and/or confounders (i.e., variables that impact both wellbeing and dementia, and thus could induce a spurious association) of the association between wellbeing and dementia. We conclude by discussing next steps to test mediation hypotheses and to account for potential confounding in the relation between wellbeing and dementia.

Corticotropin-releasing hormone and obesity: From fetal life to adulthood

Obesity is among the most common chronic disorders, worldwide. It is a complex disease that reflects the interactions between environmental influences, multiple genetic allelic variants, and behavioral factors. Recent developments have also shown that biological conditions in utero play an important role in the programming of energy homeostasis systems and might have an impact on obesity and metabolic disease risk. The corticotropin-releasing hormone (CRH) family of neuropeptides, as a central element of energy homeostasis, has been evaluated for its role in the pathophysiology of obesity. This review aims to summarize the relevance and effects of the CRH family of peptides in the pathophysiology of obesity spanning from fetal life to adulthood.

High perceived stress is associated with decreased sensory-specific satiety in humans

Previous studies have shown that chronic stress increases food intake. One possible mechanism may be due to altered sensory-specific satiety (SSS) among people with high level of chronic stress. In the current study, seventy-six participants were divided into either high-stress or low-stress groups according to their Perceived Stress Scale (PSS) scores. Participants were assigned to consume one of two foods (banana milk and corn soup) ad libitum until they felt comfortably satiated. Before and after eating, participants rated their liking and wanting for the flavor and the odor (via retronasal and orthonasal routes) of the eaten and uneaten foods. Individual interoceptive sensibility and eating behavior were measured using the Multidimensional Assessment of Interoceptive Awareness (MAIA) and Reasons Individuals Stop Eating Questionnaire (RISE-Q-15), respectively. Compared to the low-stress group, the high-stress group demonstrated blunted SSS to the whole food flavor. No significant difference was found for olfactory-specific satiety (retronasal or orthonasal) between the two groups. In addition, across the whole sample of participants, MAIA total score was positively associated with the magnitude of SSS (r = 0.29, p = 0.01). These results indicate that chronic perceived stress may play a role in the experience of reward during eating.

Ramadan fasting in the third trimester of pregnancy and postpartum colostrum cortisol concentrations in Morocco

Breast milk cortisol concentration varies among and within lactating women, but the causes and consequences of variation are not yet fully understood. This study investigated whether maternal fasting from food and water for over 16 h per day during the third trimester of pregnancy was associated with increased concentrations of cortisol in colostrum during the month of Ramadan in a Moroccan sample. Participants were women who gave birth at the public maternity hospital in Rabat, Morocco throughout the month of and month following Ramadan. Participants completed interviews (N = 92), underwent anthropometric assessment (N = 73), and colostrum samples (N = 63) were collected approximately 48-72 h postpartum. Cortisol analysis was completed on a subset of colostrum samples (N = 43). Women were categorized as fasting every day of Ramadan before giving birth (N = 52/92, 57%), fasting some days (N = 29/92, 32%), and not fasting (N = 11/92, 11%). For women who fasted, average fasting duration was 19.5 days (range: 1-29 days), and average time between the last day of fasting and birth was 8.8 days (range: 0-43 days). The number of days of fasting was positively associated with cortisol concentrations in colostrum (p < .009) in a multivariate analysis controlling for maternal anthropometry, hypertension and/or diabetes, and reasons for opting out of fasting. Each day of fasting was associated with a 4.05% increase in colostrum cortisol. Results are consistent with the hypothesis that maternal fasting during the third trimester of pregnancy increases breast milk cortisol and thus alters the hormonal milieu to which the infant is exposed.

POMC-specific knockdown of MeCP2 leads to adverse phenotypes in mice chronically exposed to high fat diet

Methyl-CpG binding protein 2 (MeCP2) is an epigenetic factor associated with the neurodevelopmental disorders Rett Syndrome and MECP2 duplication syndrome. Previous studies have demonstrated that knocking out MeCP2 globally in the central nervous system leads to an obese phenotype and hyperphagia, however it is not clear if the hyperphagia is the result of an increased preference for food reward or due to an increase in motivation to obtain food reward. We show that mice deficient in MeCP2 specifically in pro-opiomelanocortin (POMC) neurons have an increased preference for high fat diet as measured by conditioned place preference but do not have a greater motivation to obtain food reward using a progressive ratio task, relative to wildtype littermate controls. We also demonstrate that POMC-Cre MeCP2 knockout (KO) mice have increased body weight after long-term high fat diet exposure as well as elevated plasma leptin and corticosterone levels compared to wildtype mice. Taken together, these results are the first to show that POMC-specific loss-of-function Mecp2 mutations leads to dissociable effects on the rewarding/motivational properties of food as well as changes to hormones associated with body weight homeostasis and stress.

Suppressive action of nesfatin-1 and nesfatin-1-like peptide on cortisol synthesis in human adrenal cortex cells

Nucleobindin-derived peptides, nesfatin-1 [NESF-1] and nesfatin-1-like-peptide [NLP] have diverse roles in endocrine and metabolic regulation. While both peptides showed a stimulatory effect on the synthesis of proopiomelanocortin (POMC), the adrenocorticotropic hormone (ACTH) precursor in mouse corticotrophs, whether NESF-1 and NLP have any direct effect on glucocorticoid [GC] synthesis in the adrenal cortex remains unknown. The main aim of this study was to determine if NESF-1 and/or NLP act directly on adrenal cortex cells to regulate cortisol synthesis in vitro. Whether NLP injection affects stress-hormone gene expression in the adrenal gland and pituitary in vivo in mice was also assessed. In addition, cortisol synthetic pathway in Nucb1 knockout mice was studied. Human adrenal cortical [H295R] cells showed immunoreactivity for both NUCB1/NLP and NUCB2/NESF-1. NLP and NESF-1 decreased the abundance of steroidogenic enzyme mRNAs, and cortisol synthesis and release through the AC/PKA/CREB pathway in H295R cells. Similarly, intraperitoneal injection of NLP in mice decreased the expression of enzymes involved in glucocorticoid (GC) synthesis in the adrenal gland while increasing the expression of Pomc, Pcsk1 and Crhr1 in the pituitary. Moreover, the melanocortin 2 receptor (Mc2r) mRNA level was enhanced in the adrenal gland samples of NLP injected mice. However, the global genetic disruption in Nucb1 did not affect most steroidogenic enzyme mRNAs, and Pomc, Pcsk2 and Crhr1 mRNAs in mice adrenal gland and pituitary gland, respectively. Collectively, these data provide the first evidence for a direct inhibition of cortisol synthesis and secretion by NLP and NESF-1. NUCB peptides might still elicit a net stimulatory effect on GC synthesis and secretion through their positive effects on ACTH-MC2R pathway in the pituitary.

Association of admission cortisol levels with outcomes and treatment response in patients at nutritional risk : A secondary analysis of a randomized clinical trial

INTRODUCTION

Cortisol is a metabolically active stress hormone that may play a role in the pathogenesis of malnutrition. We studied the association between admission cortisol levels and nutritional parameters, disease severity, and response to nutritional support among medical inpatients at nutritional risk.

METHODS

Admission cortisol was measured in a subset of 764 patients participating in the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a multicentre, randomized-controlled trial that compared individualized nutritional support with usual nutritional care.

RESULTS

Overall, mean cortisol levels were 570 (± 293) nmol/L and significantly higher in patients with high nutritional risk (NRS ≥ 5) and in patients reporting loss of appetite. Cortisol levels in the highest quartile (> 723 nmol/l) were associated with adverse outcomes including mortality at 30 days and 5 years (adjusted HR 2.31, [95%CI 1.47 to 3.62], p = 0.001 and 1.51, [95%CI 1.23 to 1.87], p < 0.001). Nutritional treatment tended to be more effective regarding mortality reduction in patients with high vs. low cortisol levels (adjusted OR of nutritional support 0.54, [95%CI 0.24 to 1.24] vs. OR 1.11, [95%CI 0.6 to 2.04], p for interaction = 0.134). This effect was most pronounced in the subgroup of patients with severe malnutrition (NRS 2002 ≥ 5, p for interaction = 0.047).

CONCLUSION

This secondary analysis of a randomized nutritional trial suggests that cortisol levels are linked to nutritional and clinical outcome among multimorbid medical patients at nutritional risk and may help to improve risk assessment, as well as response to nutritional treatment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02517476.

Aging, testosterone, and neuroplasticity: friend or foe?

Neuroplasticity or neural plasticity implicates the adaptive potential of the brain in response to extrinsic and intrinsic stimuli. The concept has been utilized in different contexts such as injury and neurological disease. Neuroplasticity mechanisms have been classified into neuroregenerative and function-restoring processes. In the context of injury, neuroplasticity has been defined in three post-injury epochs. Testosterone plays a key yet double-edged role in the regulation of several neuroplasticity alterations. Research has shown that testosterone levels are affected by numerous factors such as age, stress, surgical procedures on gonads, and pharmacological treatments. There is an ongoing debate for testosterone replacement therapy (TRT) in aging men; however, TRT is more useful in young individuals with testosterone deficit and more specific subgroups with cognitive dysfunction. Therefore, it is important to pay early attention to testosterone profile and precisely uncover its harms and benefits. In the present review, we discuss the influence of environmental factors, aging, and gender on testosterone-associated alterations in neuroplasticity, as well as the two-sided actions of testosterone in the nervous system. Finally, we provide practical insights for further study of pharmacological treatments for hormonal disorders focusing on restoring neuroplasticity.

Mapping the network biology of metabolic response to stress in posttraumatic stress disorder and obesity

The co-occurrence of stress-induced posttraumatic stress disorder (PTSD) and obesity is common, particularly among military personnel but the link between these conditions is unclear. Individuals with comorbid PTSD and obesity manifest other physical and psychological problems, which significantly diminish their quality of life. Current understanding of the pathways connecting stress to PTSD and obesity is focused largely on behavioral mediators alone with little consideration of the biological regulatory mechanisms that underlie their co-occurrence. In this work, we leverage prior knowledge to systematically highlight such bio-behavioral mechanisms and inform on the design of confirmatory pilot studies. We use natural language processing (NLP) to extract documented regulatory interactions involved in the metabolic response to stress and its impact on obesity and PTSD from over 8 million peer-reviewed papers. The resulting network describes the propagation of stress to PTSD and obesity through 34 metabolic mediators using 302 documented regulatory interactions supported by over 10,000 citations. Stress jointly affected both conditions through 21 distinct pathways involving only two intermediate metabolic mediators out of a total of 76 available paths through this network. Moreover, oxytocin (OXT), Neuropeptide-Y (NPY), and cortisol supported an almost direct propagation of stress to PTSD and obesity with different net effects. Although stress upregulated both NPY and cortisol, the downstream effects of both markers are reported to relieve PTSD severity but exacerbate obesity. The stress-mediated release of oxytocin, however, was found to concurrently downregulate the severity of both conditions. These findings highlight how a network-informed approach that leverages prior knowledge might be used effectively in identifying key mediators like OXT though experimental verification of signal transmission dynamics through each path will be needed to determine the actual likelihood and extent of each marker’s participation.

How exposure to chronic stress contributes to the development of type 2 diabetes: A complexity science approach

Chronic stress contributes to the onset of type 2 diabetes (T2D), yet the underlying etiological mechanisms are not fully understood. Responses to stress are influenced by earlier experiences, sex, emotions and cognition, and involve a complex network of neurotransmitters and hormones, that affect multiple biological systems. In addition, the systems activated by stress can be altered by behavioral, metabolic and environmental factors. The impact of stress on metabolic health can thus be considered an emergent process, involving different types of interactions between multiple variables, that are driven by non-linear dynamics at different spatiotemporal scales. To obtain a more comprehensive picture of the links between chronic stress and T2D, we followed a complexity science approach to build a causal loop diagram (CLD) connecting the various mediators and processes involved in stress responses relevant for T2D pathogenesis. This CLD could help develop novel computational models and formulate new hypotheses regarding disease etiology.

NPFF Decreases Activity of Human Arcuate NPY Neurons: A Study in Embryonic-Stem-Cell-Derived Model

Restoring the control of food intake is the key to obesity management and prevention. The arcuate nucleus (ARC) of the hypothalamus is extensively being studied as a potential anti-obesity target. Animal studies showed that neuropeptide FF (NPFF) reduces food intake by its action in neuropeptide Y (NPY) neurons of the hypothalamic ARC, but the detailed mode of action observed in human neurons is missing, due to the lack of a human-neuron-based model for pharmacology testing. Here, we validated and utilized a human-neural-stem-cell-based (hNSC) model of ARC to test the effects of NPFF on cellular pathways and neuronal activity. We found that in the human neurons, decreased cAMP levels by NPFF resulted in a reduced rate of cytoplasmic calcium oscillations, indicating an inhibition of ARC NPY neurons. This suggests the therapeutic potential of NPFFR2 in obesity. In addition, we demonstrate the use of human-stem-cell-derived neurons in pharmacological applications and the potential of this model to address functional aspects of human hypothalamic neurons.

Daily variation of the cortisol and insulin concentration, glycemia, surface temperature, and behavior patterns due the administration of equine Chorionic Gonadotropin in rams

Sex steroids can modulate the circadian rhythmicity of some physiological and behavioral functions of sheep. During the non-breeding season, Corriedale rams have a low testosterone concentration, but the administration of equine Chorionic Gonadotropin (eCG) stimulates its secretion. Therefore, the daily variation of cortisol and insulin concentrations, glycemia, behavioral pattern (eating, ruminating, standing, lying, and sleeping), and rostral and eye surface temperatures were compared in rams treated or not treated with eCG during the non-breeding season [between August (late winter) and September (early spring)]. Twenty Corriedale adult rams (BW 63.4 ± 7.3 kg; BCS: 3.5 ± 0.5; mean ± SD; age: 2-3 years old) were randomly assigned to 1 of 2 treatments: a) Treated: administration of 1000 IU of eCG intramuscularly and b) Control: control, without application of eCG. All the rams were managed under the same feeding and environmental conditions (individual pens outdoors). All variables were measured each hour for 26 h, except testosterone and insulin that were measured at 09:00, 10:00, 12:00, 15:00, 18:00, 21:00, 22:00, 24:00, 03:00, 06:00, 09:00 and 11:00 h. Testosterone and cortisol concentration were greater in Treated than Control rams (testosterone: 32.7 ± 0.7 nmol/L vs 5.8 ± 0.7 nmol/L; P <0.0001; cortisol: 11.3 ± 0.6 nmol/L vs 9.9 ± 0.6 nmol/L; P =0.02). The eye surface temperature was 0.9°C lower in the Treated than in the Control rams (P =0.004). The characteristics of the daily variation pattern of cortisol, glycemia, glycemia:insulin ratio, and surface temperature were not affected by the treatment, the acrophases being at ∼06:00 h, ∼18:00 h, ∼08:00 h, and ∼11:00 h, respectively. The acrophase of insulin concentration was observed earlier in Treated than in Control rams (13:02 ± 0:56 vs 15:47 ± 0:53; P =0.04). Additionally, the acrophase of the time spent eating was advanced in Treated rams (09:48 ± 00:16 vs 10:20 ± 00:16; P =0.04) and sleeping (21:39 ± 00:57 vs 02:02 ± 01:06; P <0.0001). Treated rams slept less time than Control rams (P =0.04). In conclusion, the administration of eCG modulated the daily variation pattern of insulin concentration and the behavioral pattern (period in which rams were observed eating and sleeping). Nevertheless, although there was a greater cortisol concentration and reduced eye surface temperature, the administration of eCG did not modify their daily variation pattern, suggesting that this is robust, limiting the effect of testosterone on their basal pattern.

Stress-induced alterations in HPA-axis reactivity and mesolimbic reward activation in individuals with emotional eating

BACKGROUND

Emotional eating has emerged as a contributing factor to overeating, potentially leading to obesity or disordered eating behaviors. However, the underlying biological mechanisms related to emotional eating remain unclear. The present study examined emotional, hormonal, and neural alterations elicited by an acute laboratory stressor in individuals with and without emotional eating.

METHODS

Emotional (n = 13) and non-emotional eaters (n = 15) completed two main study visits, one week apart: one visit included a Stress version and the other a No-stress version of the Maastricht Acute Stress Task (MAST). Immediately pre- and post-MAST, blood was drawn for serum cortisol and participants rated their anxiety level. After the MAST, participants completed a Food Incentive Delay (FID) task during functional magnetic resonance imaging (fMRI), followed by an ad libitum snack period.

RESULTS

Emotional eaters exhibited elevated anxiety (p = 0.037) and cortisol (p = 0.001) in response to the Stress MAST. There were no changes in anxiety or cortisol among non-emotional eaters in response to the Stress MAST or in either group in response to the No-stress MAST. In response to the Stress MAST, emotional eaters exhibited reduced activation during anticipation of food reward in mesolimbic reward regions (caudate: p = 0.014, nucleus accumbens: p = 0.022, putamen: p = 0.013), compared to non-emotional eaters. Groups did not differ in snack consumption.

CONCLUSIONS

These data indicate disrupted neuroendocrine and neural responsivity to psychosocial stress amongst otherwise-healthy emotional eaters, who demonstrated hyperactive HPA-axis response coupled with hypoactivation in reward circuitry. Differential responsivity to stress may represent a risk factor in the development of maladaptive eating behaviors.

Cortisol Reactivity to a Digital Version of Trier Social Stress Test and Eating Behavior in Non-Overweight and Overweight Adolescents: A Pilot Study

(1) Background: In the present pilot study, we examined the response of cortisol to a digital version of the Trier Social Stress Test (TSST) and corresponding eating preferences in non-overweight and overweight adolescents. (2) Methods: The experimental study group included 35 adolescents aged 15.7 ± 0.5 years (16 boys and 19 girls). The participants were split into two groups: non-overweight (N = 24) and overweight (N = 11), according to the Body Mass Index (BMI). We induced acute stress in all participants, using a digital version of the Trier Social Stress Test (TSST), with three different digital tasks. We measured salivary cortisol before the test (T0), during the stress induction by digital tasks (T5, T10, T15), and 25 min after the stress test (T40). The Health Behavior in School-Aged Children Questionnaire (HBSC) was administered to assess the influence of stress on eating behavior: the consumption of fruit, vegetables, sweets, and soft drinks and the frequency of snacks. (3) Results: Among the entire group of adolescents, we observed a significant difference between the sexes in terms of cortisol response, girls being predominantly hyperreactive (13 girls compared to 5 boys, p = 0.03). In overweight adolescents, the cortisol reactivity was lower in boys and higher in girls (p = 0.05). The overweight hyperreactive adolescents, as compared to the hyporeactive ones, had a higher frequency of daily consumption of sweets (25% vs. 0%) and soft drink (25% vs. 0). (4) Conclusions: The individual patterns of cortisol reactivity to laboratory-induced stress could be associated with an increased risk of unhealthy eating behavior in adolescents.

Cortisol Reactivity to a Digital Version of Trier Social Stress Test and Eating Behavior in Non-Overweight and Overweight Adolescents: A Pilot Study

(1) Background: In the present pilot study, we examined the response of cortisol to a digital version of the Trier Social Stress Test (TSST) and corresponding eating preferences in non-overweight and overweight adolescents. (2) Methods: The experimental study group included 35 adolescents aged 15.7 ± 0.5 years (16 boys and 19 girls). The participants were split into two groups: non-overweight (N = 24) and overweight (N = 11), according to the Body Mass Index (BMI). We induced acute stress in all participants, using a digital version of the Trier Social Stress Test (TSST), with three different digital tasks. We measured salivary cortisol before the test (T0), during the stress induction by digital tasks (T5, T10, T15), and 25 min after the stress test (T40). The Health Behavior in School-Aged Children Questionnaire (HBSC) was administered to assess the influence of stress on eating behavior: the consumption of fruit, vegetables, sweets, and soft drinks and the frequency of snacks. (3) Results: Among the entire group of adolescents, we observed a significant difference between the sexes in terms of cortisol response, girls being predominantly hyperreactive (13 girls compared to 5 boys, p = 0.03). In overweight adolescents, the cortisol reactivity was lower in boys and higher in girls (p = 0.05). The overweight hyperreactive adolescents, as compared to the hyporeactive ones, had a higher frequency of daily consumption of sweets (25% vs. 0%) and soft drink (25% vs. 0). (4) Conclusions: The individual patterns of cortisol reactivity to laboratory-induced stress could be associated with an increased risk of unhealthy eating behavior in adolescents.

Binge Watching during COVID-19: Associations with Stress and Body Weight

Binge watching is becoming increasingly common and may impact energy balance and body weight. The COVID-19 pandemic has created conditions conducive to binge watching and increased stress. We investigated relationships between COVID-related stress and binge watching behaviors, and potential variation in this relationship by body weight. Adults (n = 466) completed a cross-sectional online survey assessing binge watching behaviors during and before the pandemic, COVID-related stress, and body weight. Participants reported an increase in binge watching frequency from before to during the pandemic (F1,401 = 99.970, p < 0.001), with rates of high binge watching ("3-4 times per week" to "3 or more times per day") increasing from 14.6% to 33.0%. Binge watching episode duration increased from 3.26 ± 1.89 h to 3.92 ± 2.08 h (p < 0.001). The increase in binge watching frequency was greatest in individuals with obesity and high stress (F 4,401 = 4.098, p = 0.003). Participants reporting high stress reported higher frequency of eating while binge watching, as well as higher levels of negative emotional triggers, consequences to binge watching, and lack of control over binge watching (all p < 0.001). Our results show that binge watching increased during the pandemic, with greater increases among individuals reporting higher COVID-related stress, especially those with obesity, and concomitant effects on eating, and highlight a need for interventions to minimize the obesogenic impact of binge watching during the pandemic.

Effects of Growth Hormone Receptor Ablation in Corticotropin-Releasing Hormone Cells

Corticotropin-releasing hormone (CRH) cells are the dominant neuronal population responsive to the growth hormone (GH) in the paraventricular nucleus of the hypothalamus (PVH). However, the physiological importance of GH receptor (GHR) signaling in CRH neurons is currently unknown. Thus, the main objective of the present study was to investigate the consequences of GHR ablation in CRH-expressing cells of male and female mice. GHR ablation in CRH cells did not cause significant changes in body weight, body composition, food intake, substrate oxidation, locomotor activity, glucose tolerance, insulin sensitivity, counterregulatory response to 2-deoxy-D-glucose and ghrelin-induced food intake. However, reduced energy expenditure was observed in female mice carrying GHR ablation in CRH cells. The absence of GHR in CRH cells did not affect anxiety, circadian glucocorticoid levels or restraint-stress-induced corticosterone secretion and activation of PVH neurons in both male and female mice. In summary, GHR ablation, specifically in CRH-expressing neurons, does not lead to major alterations in metabolism, hypothalamic-pituitary-adrenal axis, acute stress response or anxiety in mice. Considering the previous studies showing that central GHR signaling regulates homeostasis in situations of metabolic stress, future studies are still necessary to identify the potential physiological importance of GH action on CRH neurons.

Morphological Analysis of the Hindbrain Glucose Sensor-Hypothalamic Neural Pathway Activated by Hindbrain Glucoprivation

Lowered glucose availability, sensed by the hindbrain, has been suggested to enhance gluconeogenesis and food intake as well as suppress reproductive function. In fact, our previous histological and in vitro studies suggest that hindbrain ependymal cells function as a glucose sensor. The present study aimed to clarify the hindbrain glucose sensor-hypothalamic neural pathway activated in response to hindbrain glucoprivation to mediate counterregulatory physiological responses. Administration of 2-deoxy-D-glucose (2DG), an inhibitor of glucose utilization, into the fourth ventricle (4V) of male rats for 0.5 hour induced messenger RNA (mRNA) expression of c-fos, a marker for cellular activation, in ependymal cells in the 4V, but not in the lateral ventricle, the third ventricle or the central canal without a significant change in blood glucose and testosterone levels. Administration of 2DG into the 4V for 1 hour significantly increased blood glucose levels, food intake, and decreased blood testosterone levels. Simultaneously, the expression of c-Fos protein was detected in the 4V ependymal cells; dopamine β-hydroxylase-immunoreactive cells in the C1, C2, and A6 regions; neuropeptide Y (NPY) mRNA-positive cells in the C2; corticotropin-releasing hormone (CRH) mRNA-positive cells in the hypothalamic paraventricular nucleus (PVN); and NPY mRNA-positive cells in the arcuate nucleus (ARC). Taken together, these results suggest that lowered glucose availability, sensed by 4V ependymal cells, activates hindbrain catecholaminergic and/or NPY neurons followed by CRH neurons in the PVN and NPY neurons in the ARC, thereby leading to counterregulatory responses, such as an enhancement of gluconeogenesis, increased food intake, and suppression of sex steroid secretion.

Cortisol in relation to problematic eating behaviours, adiposity and symptom profiles in Major Depressive Disorder

Aims

Major Depressive Disorder (MDD) is associated with an increased risk of chronic disease related to weight gain, problematic eating behaviours and neuroendocrine changes. MDD is frequently associated with altered hypothalamic-pituitary-adrenal axis activity and cortisol secretion, where cortisol has been implicated in regulating energy balance, food intake and depressogenic weight changes. However, little research has examined the relationships between cortisol, adiposity and depressogenic problematic eating behaviours.

Method

Plasma cortisol concentrations were compared between 37 participants with MDD reporting appetite/weight loss, 43 participants with MDD reporting appetite/weight gain, and 60 healthy controls, by sex. Associations between cortisol, indices of adiposity and problematic eating behaviours were then assessed after accounting for demographic variables and depressive symptoms. Depressive symptoms were assessed using the Depression subscale of the Depression, Anxiety and Stress Scale, and eating behaviours with the Dutch Eating Behaviours Questionnaire and Yale Food Addiction Scale.

Results

Participants with MDD reporting appetite/weight loss had higher cortisol compared to controls, and marginally higher cortisol than those with MDD reporting appetite/weight gain. Cortisol negatively and significantly accounted for unique variance in body mass index and waist circumference after accounting for variance associated with age, sex and depressive symptoms, however it was not a significant predictor of problematic eating behaviours, such as emotional eating or food addiction. Cortisol concentrations did not differ between sexes.

Conclusion

The results indicate that cortisol is related to lower indices of adiposity and depressogenic symptoms of appetite/weight loss but is not related to problematic eating behaviours and appetite increases in MDD. These findings provide further evidence that the melancholic and atypical subtypes of MDD are associated with differential neuroendocrine and anthropometric indices, as well as behavioural and symptom profiles. Further research investigating the temporal nature of the identified relationships may assist in facilitating the development of improved interventions for individuals affected by weight changes in MDD.

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Appetite changes, adiposity and problematic eating in Major Depressive Disorder (MDD) were examined relative to cortisol.

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Cortisol was higher in those with MDD with decreased/unchanged appetite/weight than controls, and marginally higher than those with MDD with increased appetite/weight.

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Cortisol was a negative predictor of indices of adiposity, but was not associated with problematic eating.

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Cortisol may be more relevant to melancholic compared to atypical MDD, supporting differential neuroendocrine and behavioural symptom profiles between depressogenic subtypes.

Eat, sleep, repeat - endocrine regulation of behavioural circadian rhythms

The adaptation of organisms to a rhythmic environment is mediated by an internal timing system termed the circadian clock. In mammals, molecular clocks are found in all tissues and organs. This circadian clock network regulates the release of many hormones, which in turn influence some of the most vital behavioural functions. Sleep-wake cycles are under strict circadian control with strong influence of rhythmic hormones such as melatonin, cortisol and others. Food intake, in contrast, receives circadian modulation through hormones such as leptin, ghrelin, insulin and orexin. A third behavioural output covered in this review is mating and bonding behaviours, regulated through circadian rhythms in steroid hormones and oxytocin. Together, these data emphasize the pervasive influence of the circadian clock system on behavioural outputs and its mediation through endocrine networks.

Periphery signals generated by Piezo-mediated stomach stretch and Neuromedin-mediated glucose load regulate the Drosophila brain nutrient sensor

Nutrient sensors allow animals to identify foods rich in specific nutrients. The Drosophila nutrient sensor, diuretic hormone 44 (DH44) neurons, helps the fly to detect nutritive sugar. This sensor becomes operational during starvation; however, the mechanisms by which DH44 neurons or other nutrient sensors are regulated remain unclear. Here, we identified two satiety signals that inhibit DH44 neurons: (1) Piezo-mediated stomach/crop stretch after food ingestion and (2) Neuromedin/Hugin neurosecretory neurons in the ventral nerve cord (VNC) activated by an increase in the internal glucose level. A subset of Piezo⁺ neurons that express DH44 neuropeptide project to the crop. We found that DH44 neuronal activity and food intake were stimulated following a knockdown of piezo in DH44 neurons or silencing of Hugin neurons in the VNC, even in fed flies. Together, we propose that these two qualitatively distinct peripheral signals work in concert to regulate the DH44 nutrient sensor during the fed state.

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.

Choline and Folic Acid in Diets Consumed during Pregnancy Interact to Program Food Intake and Metabolic Regulation of Male Wistar Rat Offspring

BACKGROUND

North American women consume high folic acid (FA), but most are not meeting the adequate intakes for choline. High-FA gestational diets induce an obesogenic phenotype in rat offspring. It is unclear if imbalances between FA and other methyl-nutrients (i.e., choline) account for these effects.

OBJECTIVE

This study investigated the interaction of choline and FA in gestational diets on food intake, body weight, one-carbon metabolism, and hypothalamic gene expression in male Wistar rat offspring.

METHODS

Pregnant Wistar rats were fed an AIN-93G diet with recommended choline and FA [RCRF; 1-fold, control] or high (5-fold) FA with choline at 0.5-fold [low choline and high folic acid (LCHF)], 1-fold [recommended choline and high folic acid (RCHF)], or 2.5-fold [high choline and high folic acid (HCHF)]. Male offspring were weaned to an RCRF diet for 20 wk. Food intake, weight gain, plasma energy-regulatory hormones, brain and plasma one-carbon metabolites, and RNA sequencing (RNA-seq) in pup hypothalamuses were assessed.

RESULTS

Adult offspring from LCHF and RCHF, but not HCHF, gestational diets had 10% higher food intake and weight gain than controls (P < 0.01). HCHF newborn pups had lower plasma insulin and leptin compared with LCHF and RCHF pups (P < 0.05), respectively. Pup brain choline (P < 0.05) and betaine (P < 0.01) were 22-33% higher in HCHF pups compared with LCHF pups; methionine was ∼23% lower after all high FA diets compared with RCRF (P < 0.01). LCHF adult offspring had lower brain choline (P < 0.05) than all groups and lower plasma 5-methyltetrahydrofolate (P < 0.05) than RCRF and RCHF groups. HCHF adult offspring had lower plasma cystathionine (P < 0.05) than LCHF adult offspring and lower homocysteine (P < 0.01) than RCHF and RCRF adult offspring. RNA-seq identified 144 differentially expressed genes in the hypothalamus of HCHF newborns compared with controls.

CONCLUSIONS

Increased choline in gestational diets modified the programming effects of high FA on long-term food intake regulation, plasma energy-regulatory hormones, one-carbon metabolism, and hypothalamic gene expression in male Wistar rat offspring, emphasizing a need for more attention to the choline and FA balance in maternal diets.

Mid-gestation low-dose LPS administration results in female-specific excessive weight gain upon a western style diet in mouse offspring

Gestational complications, including preeclampsia and gestational diabetes, have long-term adverse consequences for offspring's metabolic and cardiovascular health. A low-grade systemic inflammatory response is likely mediating this. Here, we examine the consequences of LPS-induced gestational inflammation on offspring's health in adulthood. LPS was administered to pregnant C57Bl/6J mice on gestational day 10.5. Maternal plasma metabolomics showed oxidative stress, remaining for at least 5 days after LPS administration, likely mediating the consequences for the offspring. From weaning on, all offspring was fed a control diet; from 12 to 24 weeks of age, half of the offspring received a western-style diet (WSD). The combination of LPS-exposure and WSD resulted in hyperphagia and increased body weight and body fat mass in the female offspring. This was accompanied by changes in glucose tolerance, leptin and insulin levels and gene expression in liver and adipose tissue. In the hypothalamus, expression of genes involved in food intake regulation was slightly changed. We speculate that altered food intake behaviour is a result of dysregulation of hypothalamic signalling. Our results add to understanding of how maternal inflammation can mediate long-term health consequences for the offspring. This is relevant to many gestational complications with a pro-inflammatory reaction in place.

Stress-Induced Suppression of Food Intake in Overweight and Obese Adolescents

OBJECTIVE

Overweight adolescents exhibit greater cortisol reactivity in response to acute stress and are more likely to eat in response to emotional cues, which suggest an increased susceptibility to stress-induced eating. The purpose of this study was to examine the biological (cortisol and α-amylase reactivity) and behavioral (caloric intake) responses to an acute stressor in overweight adolescents.

METHODS

Fifty-one adolescents ages 14 to 19 years (47% female, 55% white; body mass index, 31.2 ± 0.8 kg/m) were exposed to the Trier Social Stress Test and a control condition on separate days. Immediately after each condition, participants were provided with snacks to eat at their leisure. Reactivity was assessed via salivary cortisol and α-amylase area under the curve (AUC), and adolescents were categorized as high or low reactors.

RESULTS

Cortisol AUC was higher during the stress condition (19.6 ± 0.2 μg/dl · min) compared with the control condition (11.4 ± 0.9 μg/dl · min, p < .001). α-Amylase AUC was not different during the stress condition (9999 ± 987 U/ml · min) compared with the control condition (8762 ± 865 U/ml · min, p = .145). Overall, adolescents consumed fewer calories during the stress condition (488 ± 51 kcal) compared with the control condition (637 ± 42 kcal, p = .007). High cortisol reactors decreased their calorie consumption from the control condition (716 ± 52 kcal) to the stress condition (457 ± 53 kcal, p = .001), whereas low cortisol reactors did not change their consumption (stress: 518 ± 87 kcal versus control: 561 ± 62 kcal, p = .574).

CONCLUSION

High cortisol reactivity in overweight adolescents resulted in decreased calorie consumption after an acute stressor. Further research is needed to understand the mechanisms underlying stress-induced suppression of food intake in overweight adolescents.

Identifying stress-related eating in behavioural research: A review

Stress is a commonly reported precipitant of overeating. Understanding the relationship between stress and food intake is important, particularly in view of the increasing prevalence of obesity. The purpose of this review is to examine how stress-related eating has been defined and measured in the literature to date. There are no established diagnostic criteria or gold standards for quantification of stress-related eating. Questionnaires relying on the accuracy of self-report are the mainstay of identifying people who tend to eat in response to stress and emotions. There is a paucity of clinical research linking objective measurements of stress and appetite with self-reported eating behaviour. Limitations of the methodological approaches used and the heterogeneity between studies leave significant knowledge gaps in our understanding of the mechanism of stress related eating, and how best to identify it. These issues are discussed, and areas for further research are explored.

Exercise-related factors that influence post-exercise energy intake: A psychological perspective

OBJECTIVES

Exercise confers numerous health benefits; however, unhealthy, or excessive food and drink consumption post-exercise may counteract at least some of these benefits. There is emerging evidence that certain exercise-related factors, including the psychological experiences associated with different forms of exercise motivation, may influence post-exercise energy intake. Questions remain, though, about the optimal exercise characteristics that may reduce overconsumption of food/drink post-exercise.

DESIGN

Narrative review.

METHODS

In this narrative review, we overview the developing body of literature linking the psychological experiences in exercise with subsequent energy intake, focusing first on the relationship between exercise motivation and food consumption, and then on practical strategies which may be utilised to promote healthier post-exercise food choices.

RESULTS

Preliminary evidence suggests that psychological experiences associated with high-quality autonomous motivation for exercise may reduce subsequent energy intake. Exercise factors (both psychological and physiological in nature) that have been shown to influence post-exercise energy consumption may interact, resulting in synergistic or antagonistic effects on subsequent food and drink consumption, through mechanisms which have not been considered previously.

CONCLUSIONS

Exercise experiences may be shaped to promote healthier subsequent eating behaviours and future work is encouraged to enable researchers to identify combinations of exercise conditions and experiences that have the strongest influence on post-exercise food and drink consumption.

The association of work stress and night work with nutrient intake - a prospective cohort study

Objectives:

In a prospective study among workers in an airline company, we explored whether change in work stress symptoms or night shifts was associated with nutrient intake.

Methods:

Participants in a workplace type 2 diabetes (T2D) prevention study completed a questionnaire on lifestyle, work stress symptoms, work schedule, and food intake at baseline and after 2.4-years follow-up (211 men and 155 women, 93% with increased risk for T2D). Multiple linear regression models with covariates were used to explore the associations between change in work stress symptoms or night shifts and change in nutrient intake during the follow-up.

Results:

Among men, an increase in stress and a decrease in perceived workability was associated with a higher proportion of energy (E%) from fat [β 0.6, 95% confidence interval (CI) 0.07–1.11, β 1.3, 95% CI 0.57–2.05] and saturated fat (β 0.3, 95% CI 0.02–0.58, β 0.5, 95% CI 0.14–0.90), respectively. Furthermore, a decrease in workability was associated with lower vitamin C intake (β -9.2, 95% CI -16.56– -1.84) and an increase in sleepiness with higher E% from saturated fat (β 0.7, 95% CI 0.00–0.15). Among women, an increase in work-related fatigue was associated with higher alcohol intake (β 7.5, 95% CI 1.25–13.74) and an increase of night shifts was associated with higher E% from fat (β 0.24, 95% CI 0.00–0.47) and saturated fat (β 0.17, 95% CI 0.04–0.29).

Conclusions:

Work stress symptoms were associated with a reduction in diet quality especially among men. The possible impact of work stress symptoms on workers’ dietary habits should be acknowledged and the assessment of dietary habits should consequently be incorporated into occupational health examinations.

Not the Root of the Problem-Hair Cortisol and Cortisone Do Not Mediate the Effect of Child Maltreatment on Body Mass Index

BACKGROUND

Experiencing maltreatment during childhood exerts substantial stress on the child and increases the risk for overweight and obesity later in life. The current study tests whether hair cortisol-a measure of chronic stress-and its metabolite cortisone mediate the relation between abuse and neglect on the one hand, and body mass index (BMI) on the other.

METHOD

The sample consisted of 249 participants aged 8 to 87 years (M = 36.13, SD = 19.33). We collected data on child abuse and neglect using questionnaires, measured cortisol and cortisone concentrations in hair, and BMI. In a structural model, the effects of abuse and neglect on hair cortisol, hair cortisone, and BMI were tested, as well as the covariance between hair cortisol and BMI, and hair cortisone and BMI.

RESULTS

Within the sample, 23% were overweight but not obese and 14% were obese. Higher levels of experienced abuse were related to higher cortisone concentrations in hair (β = 0.24, p < .001) and higher BMI (β = 0.17, p =.04). Neglect was not related to hair cortisol, hair cortisone, or BMI. Hair cortisol and cortisone did not mediate the association between maltreatment, and BMI. Sensitivity analyses demonstrate the same pattern of results in a subsample of adult participants currently not living with their parents. However, in younger participants who were still living with their parents, the associations between abuse and cortisone (β = 0.14, p =.35) and abuse and BMI (β = 0.02, p =.92) were no longer significant.

CONCLUSION

These findings confirm that experiencing abuse is related to higher BMI but suggest that hair cortisol and cortisone are not the mechanism underlying the association between child maltreatment and BMI. This is the first study to show abuse may be associated to elevated concentrations of hair cortisone-evidence of long-term alterations in chronic stress levels. Future research may benefit from exploring the effects of maltreatment on weight gain in longitudinal designs, including measures of other potential mediators such as eating as a coping mechanism, and more direct indicators of metabolic health.

High/low cortisol reactivity and food intake in people with obesity and healthy weight

Increased food intake, termed "comfort eating", is a pathologic coping mechanism in chronic stress. Cortisol reactivity under stress is a potent predictor of stress-induced eating behavior affecting the body mass index (BMI). However, cortisol reactivity and food intake under stress in people with obesity has not been evaluated. The aim of this study was to investigate the effect of high/low cortisol reactivity on food intake in people with obesity and healthy weight test controls, following standardized stress induction and a resting condition. Thirty-six men and women with obesity (BMI: 33.00 ± 3.23 kg/m²), as well as 36 age- and gender-matched healthy weight controls (BMI: 21.98 ± 1.81 kg/m²) were categorized into high cortisol reactors (HCR) and low cortisol reactors (LCR) in the Trier Social Stress Test (TSST). Following the TSST and a resting condition, the food intake of all participants was recorded in a standardized laboratory meal. Obese HCR demonstrated a significantly higher food intake than LCR (t (34) = -2.046, p ≤ 0.05). However, there were no significant differences between HCR and LCR in the healthy weight controls (p = 0.26). In addition, HCR of the people with obesity showed lower values in the emotion coping strategy of cognitive reappraisal than obese LCR (t (32) = 2.087, p ≤ 0.05). In conclusion, the magnitude of the cortisol reactivity to stress predicts stress-induced food intake in people with obesity, but not in the healthy weight controls. Limited use of cognitive reappraisal in emotion regulation in the obese HCR may be a marker of vulnerability to stress-induced eating.

The effect of a single, brief practice of progressive muscle relaxation after exposure to an acute stressor on subsequent energy intake

BACKGROUND

Given previous research suggests an association between stress and the intake of energy-dense foods, this study investigated whether poststressor relaxation practice can attenuate stress-induced eating.

METHODS

Twenty-five men and women were exposed to four conditions on separate days: an acute laboratory stressor (S), acute stressor followed by 20 min of relaxation (SR) in the form of Abbreviated Progressive Muscle Relaxation (APMR), relaxation alone (R), and a control condition (C). Physiological and psychological responses to stress and relaxation were assessed, in addition to the subsequent energy intake of high-energy snacks.

RESULTS

Salivary cortisol, blood pressure, heart rate, and perceived stress were transiently elevated postlaboratory stressor (S and SR compared with R and C; p < .05). Meanwhile, perceived relaxation was acutely enhanced after APMR alone (R) compared with S, SR, and C (p < .05) and in SR (immediately after the APMR) compared with S (p < .05). No difference in mean energy intake was observed between conditions (p > .05). Likewise, no differences in perceived appetite or the levels of ghrelin, leptin, and insulin were found between conditions (p > .05).

CONCLUSIONS

Much variation exists in stress-induced dietary responses, and APMR either postacute stressor or in isolation does not appear to consistently alter the intake of commonly eaten snacks.

Fat Intake and Stress Modify Sleep Duration Effects on Abdominal Obesity

Though the association between sleep duration and obesity has been generally acknowledged, there is little information about the mechanisms behind this association. The purpose of this study was to examine the effect of the fat intake and stress variables on the association between sleep duration and abdominal obesity. Data for 13,686 subjects aged ≥ 20 years from the 2013–2017 Korea National Health and Nutrition Examination Survey were used, and hierarchical and stratified logistic regression analyses were employed. In the hierarchical logistic regression analyses, fat intake and stress did not change the significance or the size of the sleep effects upon abdominal obesity. These results suggest that sleep duration does not affect abdominal obesity through fat intake or stress variables. In addition, fat intake and stress are not mediators of the sleep duration variable. However, subjects with different levels of fat intake and stress showed different associations between sleep duration and abdominal obesity. Subjects who were in the lowest or highest group of fat intake as well as self-reported stress level showed a weaker relationship between sleep duration and abdominal obesity, compared with the other groups. In conclusion, fat intake and stress modify the effects of sleep duration on abdominal obesity according to the stratified regression results.

Association between hair cortisol concentration and dietary intake among normal weight preschool children predisposed to overweight and obesity

Background

The association between chronically elevated cortisol, as measured by hair cortisol concentration (HCC), and dietary intake among children has generally not been explored. Moreover, it is unknown whether there is an association between parental HCC and dietary intake among their children.

Objective

To examine associations between HCC and dietary intake among children, and to explore the association between parental HCC and dietary intake among their children.

Methods

We conducted a cross-sectional study based on 296 children predisposed to overweight and obesity who participated in the Healthy Start study. Multiple Linear regression analyses were conducted to assess the association between HCC and total energy intake, macronutrients, fruit and vegetables, added sugar, sugar-sweetened beverages (SSB), and a diet quality index (DQI).

Results

Among the children, we found that higher HCC was associated with a lower consumption of dietary fat (β: -0.7 g/day [95% CI: -1.3, -0.0] per 100 pg/mg HCC). We found no statistically significant association between HCC and intake of total energy, protein, carbohydrate, fruit and vegetables, added sugar, SSB or DQI. We found no association between parental HCC and intake of total energy, added sugar, selected food groups or DQI among their children. However, stratified analyses showed that paternal HCC was associated with a borderline significant lower total energy intake and significantly lower protein intake, but only among daughters (adjusted β: -42 kcal/day [95% CI: -85, 0] and -2.6 g/day [95% CI: -4.4, -0.8] per 100 pg/mg HCC, respectively).

Conclusion

Among children, chronic stress as measured by HCC may be associated with a lower fat consumption, and paternal HCC may be associated with a lower intake of energy and protein among their daughters. However, the associations observed were weak, and any clinical relevance of these findings remains questionable.

The corticosteroid prednisolone increases amygdala and insula reactivity to food approach signals in healthy young men

Short- and long-term treatment with glucocorticoids is widely used in clinical practice and frequently induces features of iatrogenic Cushing syndrome, such as abdominally centered weight gain. Despite decades of glucocorticoids usage, the mechanisms underlying these side effects are still only partly understood. One possibility is that glucocorticoids impact subcortical (hypothalamus, amygdala, insula) and cortical (orbitofrontal and cingulate cortex) brain regions involved in appetite regulation and reward processing. In the present study, we used functional magnetic resonance imaging (fMRI) to study the acute effects of a prednisolone infusion on reactivity of brain reward systems to food stimuli. Twenty healthy normal-weight men were tested in a randomized, double-blind, cross-over study. After an overnight fast and infusion of either 250 mg prednisolone or placebo (always administered between 8 and 9 A M), fMRI scans were taken while presenting food and object pictures in a Go/NoGo (GNG) task. At home, participants were asked to register what they had eaten. On the following morning they came back to the lab and had a supervised ad libitum breakfast at a standardized buffet. Food-Go in contrast to Object-Go pictures yielded increased blood oxygen level dependent (BOLD) activity in hippocampus, amygdala, orbitofrontal cortex, insula and anterior cingulate cortex. Prednisolone increased activation in the bilateral amygdala and right insula for approach-associated food pictures. The buffet test did not reveal significant differences in calorie consumption or preferences of different macronutrients. However, prednisolone-induced insula reactivity to Food-Go images was associated with greater caloric intake, both at home and in the standardized buffet. In sum, we observed a specific effect of prednisolone on the BOLD response of the amygdala and insula to approach-associated food stimuli. As these brain areas have previously been implicated in hedonic eating, the present pattern of results may reflect an increased anticipated reward value of food modulated by glucocorticoids. These effects might potentially drive increased food intake and weight gain under prolonged glucocorticoid treatment.

Effects of Isolation and Social Subchronic Stresses on Food Intake and Levels of Leptin, Ghrelin, and Glucose in Male Rats

Background:

Exposure to psychological stresses can be a reason for obesity. Therefore, identifying the effective nutritional mechanisms such as feeding markers is of high necessity for the psychological stress conditions. Hence, the present study investigates the effects of subchronic isolation and social stresses on food intake, body weight differences (BWD), and levels of leptin, ghrelin, and glucose in rats.

Materials and Methods:

Eighteen male rats were randomly allocated into three groups: control (Co), isolation stress (IS), and social stress (SS) groups. Rats were under stresses for 7 days. The food intake (for three continuous hours after 16–18 h of food deprivation), BWD, levels of ghrelin, leptin, and glucose were measured.

Results:

The results showed that the food intake significantly (P < 0.05) reduced during the 1^st h in the SS group compared to the Co group. At the 2^nd h, the food intake significantly (P < 0.001 and P < 0.01, respectively) decreased in the IS group compared to the Co and SS groups. The cumulative food intake and body weight were significantly (P < 0.05) reduced in the IS group compared to the Co group. The serum ghrelin level significantly reduced in the IS group compared to the Co group.

Conclusions:

The subchronic psychological stresses led to a reduction in food intake by the reduction of serum ghrelin levels. It seems that ghrelin might have a more fundamental role in the food intake with respect to the leptin and glucose levels in subchronic stress condition. Furthermore, the decreased body weight justified the reduction of food intake, particularly in subchronic isolation stress.

Stress and Obesity: Are There More Susceptible Individuals?

PURPOSE OF REVIEW

Stress has long been suspected to be interrelated to (abdominal) obesity. However, interindividual differences in this complex relationship exist. We suggest that the extent of glucocorticoid action partly explains these interindividual differences. We provide latest insights with respect to multiple types of stressors.

RECENT FINDINGS

Increased long-term cortisol levels, as measured in scalp hair, are strongly related to abdominal obesity and to specific mental disorders. However, not all obese patients have elevated cortisol levels. Possibly, the interindividual variation in glucocorticoid sensitivity, which is partly genetically determined, may lead to higher vulnerability to mental or physical stressors. Other evidence for the important role for increased glucocorticoid action is provided by recent studies investigating associations between body composition and local and systemic corticosteroids. Stress may play a major role in the development and maintenance of obesity in individuals who have an increased glucocorticoid exposure or sensitivity. These insights may lead to more effective and individualized obesity treatment strategies.

A Role for Exercise in Attenuating Unhealthy Food Consumption in Response to Stress

It is well established that both acute and chronic stress can be detrimental to health and wellbeing by directly increasing the risk of several chronic diseases and related health problems. In addition, stress may contribute to ill-health indirectly via its downstream effects on individuals’ health-related behaviour, such as promoting the intake of unhealthy palatable foods high in fat and sugar content. This paper reviews (a) the research literature on stress-models; (b) recent research investigating stress-induced eating and (c) the potential physiological and psychological pathways contributing to stress-induced eating. Particular attention is given to (d) the role of physical exercise in attenuating acute stress, with exploration of potential mechanisms through which exercise may reduce unhealthy food and drink consumption subsequent to stressor exposure. Finally, exercise motivation is discussed as an important psychological influence over the capacity for physical exercise to attenuate unhealthy food and drink consumption after exposure to stressors. This paper aims to provide a better understanding of how physical exercise might alleviate stress-induced unhealthy food choices.

Examination of the role of obesity in the association between childhood trauma and inflammation during pregnancy

OBJECTIVE

Childhood trauma is associated with negative perinatal health outcomes including mood disorders and shorter gestation. However, effects of early life exposures on maternal biology are poorly delineated. This study examined associations between childhood trauma and inflammation, as well as the mediating role of obesity in this relationship.

METHOD

This study examined a racially diverse sample of 77 pregnant women assessed in early, mid, and late pregnancy. Assessments included the Childhood Trauma Questionnaire, Center for Epidemiologic Studies-Depression Scale, serum CRP, IL-6, and TNF-α, and prepregnancy BMI.

RESULTS

Per linear mixed models, while no direct relationships were observed between childhood trauma with IL-6 or TNF-α, physical (95% CI: 0.007, 0.080) and emotional (95% CI: 0.005, 0.046) abuse as well as emotional neglect (95% CI: 0.010, 0.051) predicted elevated CRP. Effects remained after adjustment for race, income, education, smoking status, medical conditions, and depressive symptoms. PROCESS analyses showed BMI mediated the relationship between physical abuse and both serum CRP (95% CI: 0.014, 0.062) and IL-6 (95% CI: 0.009, 0.034).

CONCLUSIONS

Exposure to childhood trauma, particularly emotional abuse, physical abuse, and emotional neglect, is associated with inflammation in pregnant women. Obesity served as 1 pathway by which physical abuse contributed to elevations in serum CRP and IL-6. Interventions targeting maternal obesity prior to pregnancy may help mitigate the effects of childhood trauma on perinatal health. These findings have relevance for understanding biological and behavioral pathways by which early life exposures contribute to maternal health. (PsycINFO Database Record

Altered functionality of the corticotrophin-releasing hormone receptor-2 in the hypothalamic paraventricular nucleus of hyperphagic maternally separated rats

Early-life stress induces endocrine and metabolic alterations that increase food intake and overweight in adulthood. The stress response activates the corticotropin-releasing hormone (CRH) and urocortins' (Ucns) system in the hypothalamic paraventricular nucleus (PVN). These peptides induce anorexic effects through CRH-R2 receptor activation; however, chronic stressed animals develop hyperphagia despite of high PVN CRH expression. We analyzed this paradoxical behavior in adult rats subjected to maternal separation (MS) for 180min/daily during post-natal days 2-14, evaluating their body weight gain, food intake, serum corticosterone and vasopressin concentrations, PVN mRNA expression of CRH-R1, CRH-R2, CRH, Ucn2, Ucn3, vasopressin and CRH-R2 protein levels. MS adults increased their feeding, weight gain as well as circulating corticosterone and vasopressin levels, evincing chronic hyperactivity of the stress system. MS induced higher PVN CRH, Ucn2 and CRH-R2 mRNA expression and protein levels of CRH-R2 showed a tendency to decrease in the cellular membrane fraction. An intra-PVN injection of the CRH-R2 antagonist antisauvagine-30 in control adults increased receptor's mRNA expression, mimicking the observed PVN receptor's up-regulation of early-life MS adults. An injection of Ucn-2 directly into the PVN reduced food intake and increased PVN pCREB/CREB ratio in control animals; in contrast, Ucn-2 was unable to reduce food intake and enhance phosphorylated-CREB levels in PVN of MS rats. In conclusion, the chronic hyperactivity of the stress axis and PVN CRH-R2 resistance to Ucn2 effects, supported impaired receptor functionality in MS animals, probably due to its chronic stimulation by CRH or Ucn2, induced by early-life stress.

The Relationship between Stress and Severe Obesity: A Case-Control Study

Background

Several etiological factors for obesity have been identified, whereas other factors related to obesity, such as stress, remain poorly understood. This study used psychiatric methods to examine the relationship between stress and obesity.

Methods

Matched study and control groups were established, and the female and male control subjects were selected separately by random sampling. The control subjects were matched with the case subjects with respect to place of residence, sex, age, date that a pension was granted, and occupation. Psychiatric and psychological methods were assessed using a questionnaire and statistical analyses.

Results

Psychiatric interviews indicated that stress was more prevalent in the study group than in the control group. Separation from parents was nearly significantly more frequently in the study group than in the control group. The questionnaire on coping mechanisms revealed that case subjects tended to resolve their problems in an active manner.

Conclusions

The aim of this case-control study was to examine the relationship between stress and obesity in individuals receiving a disability pension. We identified stress factors that affect the development of obesity. We believe our study is both necessary and important, as these findings provide valuable insight into the relationship between severe obesity and stress.

Examining the effects of cigarette smoking on food cravings and intake, depressive symptoms, and stress

PURPOSE

This study examined the relationships among smoking status and total and specific types of food cravings (i.e., high-fats, sweets, fast-food fats, and complex carbohydrates/starches) and the influence of demographic, clinical, and psychological factors on this relationship.

METHODS

Seven-hundred and twelve adults completed measures of food cravings, dietary intake, and smoking history. Heights and weights were measured. Data were analyzed using univariate and multivariate analyses while adjusting for demographic, clinical, and psychological covariates.

RESULTS

Compared to never smokers, current smokers reported more frequent cravings for high-fat foods and fast-food fats, after controlling for depression, stress, BMI and demographic factors. Current smokers also reported consuming more high-fat foods and fast-food fats. The association between cigarette smoking and total food craving was no longer significant after accounting for depression and stress, suggesting that depression and stress may account for the relationship between smoking and total food craving. Smoking did not moderate the relationship between food cravings and food intake. Nicotine dependence was positively correlated with the frequency of general food cravings and cravings for high fats, sweets, and carbohydrates/starches.

CONCLUSIONS

Cigarette smokers, and especially those with higher nicotine dependence, may have greater difficulties in addressing food craving and changing eating habits, particularly in the context of depression and stress.

Determinants of Perceived Stress in Individuals with Obesity: Exploring the Relationship of Potentially Obesity-Related Factors and Perceived Stress

OBJECTIVE

Associations of specific types of stress with increased food intake and subsequent weight gain have been demonstrated in animal models as well as in experimental and epidemiological studies on humans. This study explores the research question of to what extent potentially obesity-related factors determine perceived stress in individuals with obesity.

METHODS

N = 547 individuals with obesity participated in a cross-sectional study assessing perceived stress as the outcome variable and potential determinants of stress related to obesity. Based on the available evidence, a five factorial model of 'obesity-related obesogenic stressors' was hypothesized, including the dimensions, 'drive for thinness', 'impulse regulation', 'ineffectiveness', 'social insecurity', and 'body dissatisfaction'. The model was tested using multiple linear regression analyses.

RESULTS

The five factorial model of 'potentially obesity-related stressors' resulted in a total variance explanation of adjusted R² = 0.616 for males and adjusted R² = 0.595 for females for perceived stress. The relative variance contribution of the five included factors differed substantially for the two sexes.

CONCLUSION

The findings of this cross-sectional study support the hypothesized, potentially obesity-related factors: 'drive for thinness', 'impulse regulation', 'ineffectiveness', 'social insecurity', and 'body dissatisfaction' as relevant determinants of perceived stress in individuals with obesity.

Acute central effects of corticotropin-releasing factor (CRF) on energy balance: Effects of age and gender

Previously demonstrated age-related changes in the catabolic melanocortin system that may contribute to middle-aged obesity and aging anorexia, raise the question of the potential involvement of corticotropin-releasing factor (CRF) in these phenomena, as this catabolic hypothalamic mediator acts downstream to melanocortins. Catabolic effects of CRF were shown to be mediated by both CRF1 (hypermetabolism) and CRF2 (anorexia) receptors. To test the potential role of CRF in age-related obesity and aging anorexia, we investigated acute central effects of the peptide on energy balance in male and female rats during the course of aging. Effects of an intracerebroventricular CRF injection on food intake (FI), oxygen-consumption (VO₂), core- and tail skin temperatures (Tc and Ts) were studied in male and female Wistar rats of five different age-groups (from 3- to 24-month). Anorexigenic responsiveness was tested during 180-min re-feeding (FeedScale) following 24-h fasting. Thermoregulatory analysis was performed by indirect calorimetry (Oxymax) complemented by thermocouples recording Tc and Ts (indicating heat loss). CRF suppressed FI in 3-month male and female animals. In males, CRF-induced anorexia declined with aging, whereas in females it was maintained in all groups. The peptide increased VO₂ and Tc in all male age-groups, while the weaker hypermetabolic response characterizing 3-month females declined rapidly with aging. Thus, age-related alterations in acute central anorexigenic and hypermetabolic effects of CRF show different non-parallel patterns in males and females. Our findings underline the importance of gender differences. They also call the attention to the differential age-related changes in the CRF1 and CRF2 receptor systems.