Nocturnal levels of ghrelin and leptin and sleep in chronic insomnia

Poor quality of sleep and musculoskeletal pains among highly trained and elite athletes in Senegal

BACKGROUND

Previous studies reported that poor sleep quality (PSQ) was associated with musculoskeletal pains (MSP) and poor physical performance in athletes.

OBJECTIVE

The current study aimed at determining PSQ and its associations with MSP in some sub-Saharan athletes.

METHODS

A cross sectional study was conducted among 205 highly trained and 115 elite athletes (aged: 25 ± 2 years, Body mass index: 22.8 ± 0.9 kg/m2) in Dakar, Senegal, during a competitive season in a variety of sport disciplines including athletics, basketball, football, rugby, wrestling, tennis. Quality of sleep and MSP were assessed using the French version Pittsburgh Sleep Quality Index (PSQI) and French version of Nordic questionnaire respectively. Pain on body joints during a week was defined as seven-day MSP (MSP-7d) and PSQ for a PSQI > 5.

RESULTS

27.8% (95%CI: 23.2-32.9) of the overall sample suffered PSQ, with 33.7% (95%CI: 24.7-44.0) in basketball and 24.7% (95%CI: 16.9-34.6) in football. According to athletic status and gender, PSQ was more prevalent among highly trained (66.3; 95%CI: 55.9-75.3) and men (69.7%; 95%CI: 59.5-78.7). Among athletes with PSQ 43.8% (95%CI: 33.9-54.2) suffered MSP-7d, with 36.6%; highly trained (95%CI: 23.7-42.9) and 28.1% female. Considering body region, hips/thigh (14.6%; 95% CI: 8.74-23.4) and upper back (13.5%; 95%CI: 7.88 -21, 1) were more affected. Basketball players were more affected from MSP (MSP-7d = 38.5%; 95%CI: 24. 9-54.1) on high on wrists/hands (MSP-7d = 44.4%; 95%CI: 18.9 -73.3; P = 0.04). Based on athletic status, MSP-7d were higher on highly trained necks (100%; 95%CI: 56.1-100; p = 0.04). PSQ was associated with basketball (OR: 3.062, 95%CI: 1.130-8.300, p = 0.02) compared to Athletic. PSQ and MSP-7d were associated on Wrist/hands (OR: 3.352, 95%CI: 1.235-9.099, p = 0.01), and at the upper back (OR: 5.820, 95%CI: 2.096-16.161, p = 0.0007).

CONCLUSION

These results indicate that PSQ is considerable among Senegalese athletes and is associated with MSP during a week. Hence, we recommend to look for strategies optimizing good quality of sleep in order to reduce pains, to improve health.

Sleep restriction alters the integration of multiple information sources in probabilistic decision-making

The detrimental effects of sleep loss on overall decision-making have been well described. Due to the complex nature of decisions, there remains a need for studies to identify specific mechanisms of decision-making vulnerable to sleep loss. Bayesian perspectives of decision-making posit judgement formation during decision-making occurs via a process of integrating knowledge gleaned from past experiences (priors) with new information from current observations (likelihoods). We investigated the effects of sleep loss on the ability to integrate multiple sources of information during decision-making by reporting results from two experiments: the first implementing both sleep restriction (SR) and total sleep deprivation (TSD) protocols, and the second implementing an SR protocol. In both experiments, participants were administered the Bayes Decisions Task on which optimal performance requires the integration of Bayesian prior and likelihood information. Participants in Experiment 1 showed reduced reliance on both information sources after SR, while no significant change was observed after TSD. Participants in Experiment 2 showed reduced reliance on likelihood after SR, especially during morning testing sessions. No accuracy-related impairments resulting from SR and TSD were observed in both experiments. Our findings show SR affects decision-making through altering the way individuals integrate available sources of information. Additionally, the ability to integrate information during SR may be influenced by time of day. Broadly, our findings carry implications for working professionals who are required to make high-stakes decisions on the job, yet consistently receive insufficient sleep due to work schedule demands.

The effects of sleep disruption on metabolism, hunger, and satiety, and the influence of psychosocial stress and exercise: A narrative review

Sleep deficiency is a ubiquitous phenomenon among Americans. In fact, in the United States, ∼78% of teens and 35% of adults currently get less sleep than recommended for their age-group, and the quality of sleep appears to be getting worse for many. The consequences of sleep disruption manifest in a myriad of ways, including insulin resistance and disrupted nutrient metabolism, dysregulation of hunger and satiety, and potentially increased body weight and adiposity. Consequently, inadequate sleep is related to an increased risk of various cardiometabolic diseases, including obesity, diabetes, and heart disease. Exercise has the potential to be an effective therapeutic to counteract the deleterious effects of sleep disruption listed above, whereas chronic psychosocial stress may causally promote sleep disruption and cardiometabolic risk. Here, we provide a narrative review of the current evidence on the consequences of short sleep duration and poor sleep quality on substrate metabolism, circulating appetite hormones, hunger and satiety, and weight gain. Secondly, we provide a brief overview of chronic psychosocial stress and its impact on sleep and metabolic health. Finally, we summarise the current evidence regarding the ability of exercise to counteract the adverse metabolic health effects of sleep disruption. Throughout the review, we highlight areas where additional interrogation and future exploration are necessary.

The low ratio of ghrelin in plasma and cerebrospinal fluid might be beneficial to sleep

OBJECTIVE

Ghrelin is physiologically important for maintaining sleep rhythm. Cigarette smoking has been demonstrated to significantly increase the risk of insufficient sleep by regulating ghrelin at the central and peripheral levels. No research has been published to study the relationship between active smoking and sleep via ghrelin level in cerebrospinal fluid (CSF).

METHODS

A total of 139 Chinese males were recruited and divided into active smokers (n = 77) and non-smokers (n = 62). The levels of CSF and plasma ghrelin were measured. The Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep.

RESULTS

Non-smokers had lower PSQI scores (1.71 ± 1.93) than active smokers (3.70 ± 1.78). Non-smokers have significantly lower plasma ghrelin levels and lower plasma/CSF ghrelin ratio but higher CSF ghrelin than active smokers. Among non-smokers, plasma ghrelin levels were not correlated with PSQI scores (all p > 0.05), CSF ghrelin levels were positively correlated with PSQI scores (r = 0.309, p = 0.019), and the plasma/CSF ghrelin ratio was negatively correlated with PSQI scores (r = -0.346, p = 0.008).

CONCLUSIONS

This study is the first to reveal the relationship between cigarette smoking, high CSF ghrelin levels and insufficient sleep, suggesting that maintaining a normal plasma/CSF ghrelin ratio may be the physiological mechanism of healthy sleep, and the insufficient sleep population must quit smoking.

Sleep Profiles in Eating Disorders: A Scientometric Study on 50 Years of Clinical Research

Sleep and diet are essential for maintaining physical and mental health. These two factors are closely intertwined and affect each other in both timing and quality. Eating disorders, including anorexia nervosa and bulimia nervosa, are often accompanied by different sleep problems. In modern society, an increasing number of studies are being conducted on the relationship between eating disorders and sleep. To gain a more comprehensive understanding of this field and highlight influential papers as well as the main research domains in this area, a scientometric approach was used to review 727 publications from 1971 to 2023. All documents were retrieved from Scopus through the following string "TITLE-ABS (("sleep" OR "insomnia") AND ("anorexia nervosa" OR "bulimia nervosa" OR "binge eating" OR "eating disorder*") AND NOT "obes*") AND (LIMIT-TO (LANGUAGE, "English"))". A document co-citation analysis was applied to map the relationship between relevant articles and their cited references as well as the gaps in the literature. Nine publications on sleep and eating disorders were frequently cited, with an article by Vetrugno and colleagues on nocturnal eating being the most impactful in the network. The results also indicated a total of seven major thematic research clusters. The qualitative inspection of clusters strongly highlights the reciprocal influence of disordered eating and sleeping patterns. Researchers have modelled this reciprocal influence by taking into account the role played by pharmacological (e.g., zolpidem, topiramate), hormonal (e.g., ghrelin), and psychological (e.g., anxiety, depression) factors, pharmacological triggers, and treatments for eating disorders and sleep problems. The use of scientometric perspectives provides valuable insights into the field related to sleep and eating disorders, which can guide future research directions and foster a more comprehensive understanding of this important area.

The Role of Leptin in Rodent and Human Sleep: A Transdiagnostic Approach with a Particular Focus on Anorexia Nervosa

This narrative review addressed to both clinicians and researchers aims to assess the role of hypoleptinemia in disordered sleep with a particular focus on patients with anorexia nervosa (AN). After introducing circadian rhythms and the regulation of circulating leptin, we summarize the literature on disordered sleep in patients with AN and in fasting subjects in general. We highlight novel single-case reports of substantially improved sleep within days after initiation of off-label metreleptin treatment. These beneficial effects are set in relationship to current knowledge of disordered sleep in animal models of an impaired leptin signaling. Specifically, both absolute and relative hypoleptinemia play a major role in animal models for insomnia, obstructive sleep apnea and obesity hypoventilation syndrome. We pinpoint future research required to complement our understanding of the role of leptin in sleep in patients with acute AN. Moreover, within the section clinical applications we speculate that human recombinant leptin may be useful for the treatment of treatment-resistant sleep-wake disorders, which are associated with (relative) hypoleptinemia. Overall, we stress the role of the hormone leptin in sleep.

Total sleep deprivation decreases saliva ghrelin levels in adolescents

Ghrelin, a regulator of food intake and energy expenditure, has been shown to be associated with insufficient sleep. The goal of the present study was to investigate the effect of a single night of total sleep deprivation on fasting saliva ghrelin and on nocturnal variation of saliva ghrelin concentration. A further aim of the study was to investigate the influence of body mass index on changes in saliva ghrelin levels. Altogether 35 adolescents (18 boys; age: 13.8 ± 1.14 years) were studied on two subsequent days (sleep and total sleep deprivation). Saliva samples were collected during the two experimental nights at 21:00 hours, 01:00 hours and 06:00 hours. Total-ghrelin concentration showed a continuous increase from the evening until 06:00 hours. This increase was blunted significantly (p = 0.003) by total sleep deprivation. Total-ghrelin level was significantly lower (p = 0.02) during total sleep deprivation at 06:00 hours (median 403.6 pg ml^-1 ; 95% confidence interval: 343.1-468.9 pg ml^-1 ) as compared with values during the sleep condition (median 471.2 pg ml^-1 ; 95% confidence interval: 205.4-1578.7 pg ml^-1 ). Acyl-ghrelin levels did not present any change at the three time points, and were not affected by total sleep deprivation. Stratifying the study population according to body mass index (normal weight and overweight/obese groups), the blunting effect of total sleep deprivation was more pronounced in the obese/overweight group (sleep: median 428.2 pg ml^-1 ; 95% confidence interval: 331.3-606.9 pg ml^-1 versus total sleep deprivation: median 333.1 pg ml^-1 ; 95% confidence interval: 261.5-412.9 pg ml^-1 ; p = 0.0479). Saliva total-ghrelin concentrations gradually increased during the night, and total sleep deprivation significantly blunted this increase. This blunting effect was mainly observed in subjects with overweight/obesity. The physiological and clinical implications of the present observation are to be clarified by further studies.

Associations of insomnia with insulin resistance traits: a cross-sectional and Mendelian Randomization study

CONTEXT

Insomnia is associated with insulin resistance (IR) in observational studies, however, whether insomnia is causally associated with IR remains unestablished.

OBJECTIVE

This study aims to estimate the causal associations of insomnia with IR and its related traits.

METHODS

In primary analyses, multivariable regression (MVR) and one-sample Mendelian randomization (1SMR) analyses were performed to estimate the associations of insomnia with IR (triglyceride-glucose [TyG] index and triglyceride to high-density lipoprotein cholesterol [TG/HDL-C] ratio) and its related traits (glucose level, TG, and HDL-C) in UK Biobank. Thereafter, two-sample MR (2SMR) analyses were used to validate the findings from primary analyses. Finally, the potential mediating effects of IR on the pathway of insomnia giving rise to T2D were examined using a two-step MR design.

RESULTS

Across the MVR, 1SMR, and their sensitivity analyses, we found consistent evidence suggesting that more frequent insomnia symptoms were significantly associated with higher values of TyG index (MVR: β = 0.024, P < 2.00E-16; 1SMR: β = 0.343, P < 2.00E-16), TG/HDL-C ratio (MVR: β = 0.016, P = 1.75E-13; 1SMR: β = 0.445, P < 2.00E-16), and TG level (MVR: β = 0.019 log mg/dl, P < 2.00E-16; 1SMR: β = 0.289 log mg/dL, P < 2.00E-16) after Bonferroni adjustment. Similar evidence was obtained by using 2SMR, and mediation analysis suggested that about a quarter (25.21%) of the association between insomnia symptoms and T2D was mediated by IR.

CONCLUSIONS

This study provides robust evidence supporting that more frequent insomnia symptoms are associated with IR and its related traits across different angles. These findings indicate that insomnia symptoms can be served as a promising target to improve IR and prevent subsequent T2D.

Sleep duration of lactating mothers and its relationship with feeding pattern, milk macronutrients and related serum factors: A combined longitudinal cohort and cross-sectional study

Objective

Insufficient sleep is common in postpartum mothers. The main objectives of this study are to explore the sleep duration among Chinese lactating mothers and preliminarily investigate the relationship between sleep duration and feeding pattern. The secondary objectives are to investigate the relationships between sleep duration and milk macronutrients and between maternal-related indicators, including melatonin (MT), growth hormone (GH), ghrelin (GHRL), glucagon-like peptide-1 (GLP-1), prolactin (PRL), and cholecystokinin (CCK).

Methods

The present study comprises a longitudinal and a cross-sectional cohort from December 2019 to December 2021. Postpartum lactating women living in Shanghai were recruited through online and offline recruitment. The subjects were included in the longitudinal cohort or cross-sectional study based on their lactation period at the time of recruitment. The longitudinal cohort included a total of 115 mothers. Human milk and feeding pattern were measured and collected at 2–4 months and 5–7 months postpartum. At four predetermined follow-up time points, data on sleep duration was collected (at the time of recruitment, 2–4 months postpartum, 5–7 months postpartum, and 12–17 months postpartum). The cross-sectional study included 35 lactating mothers (2–12 months postpartum) who reported their sleep duration and provided blood samples. Mid-infrared spectroscopy (MIRS) method was used to analyze the macronutrients of breast milk, while MT, GH, GHRL, GLP-1, PRL, and CCK in maternal blood were determined by ELISA.

Results

The maternal sleep duration before pregnancy was 8.14 ± 1.18 h/d (n = 115), 7.27 ± 1.31 h/d (n = 113) for 2–4 months postpartum, 7.02 ± 1.05 h/d (n = 105) for 5–7 months postpartum, and 7.45 ± 1.05 h/d (n = 115) for 12–17 months postpartum. The incidence of insufficient sleep (<7 h/d) before pregnancy (12.17%) was significantly less than at any follow-up time after delivery (vs. 2–4 months postpartum, χ² = 10.101, p = 0.001; vs. 5–7 months postpartum, χ² = 15.281, p < 0.0001; vs. 12–17 months postpartum, χ² = 6.426, p = 0.011). The percentage of insufficient maternal sleep was highest at 5–7 months postpartum (34.29%). No significant difference was found between the incidence of insufficient sleep at 5–7 months postpartum, 2–4 months postpartum (29.20%, χ² = 0.650, p = 0.420), and 12–17 months postpartum (25.22%, χ² = 2.168, p = 0.141). At 2–4 months postpartum, the frequency of formula feeding per day is related to reduced maternal sleep duration (Standardization coefficient β = −0.265, p = 0.005, Adjusted R² = 0.061). At 2–4 months and 5–7 months postpartum, the relationship between macronutrients in breast milk and the mother's sleep duration was insignificant (all p > 0.05). Other than the positive correlation found between maternal GHRL and sleep duration (r = 0.3661, p = 0.0305), no significant relationship was observed between sleep duration and other indexes (all p > 0.05).

Conclusions

Postpartum mothers generally sleep less, but there is no correlation between insufficient sleep and the macronutrient content of breast milk. Formula feeding may be related to the mother's sleep loss, while breastfeeding (especially direct breastfeeding) may be related to increased maternal sleep duration. The findings suggest that sleep duration is related to maternal serum GHRL. More high-quality studies are needed to clarify the mechanism of these findings and provide a solid theoretical basis and support references for breastfeeding.

Ghrelin mediated regulation of neurosynaptic transmitters in depressive disorders

Ghrelin is a peptide released by the endocrine cells of the stomach and the neurons in the arcuate nucleus of the hypothalamus. It modulates both peripheral and central functions. Although ghrelin has emerged as a potent stimulator of growth hormone release and as an orexigenic neuropeptide, the wealth of literature suggests its involvement in the pathophysiology of affective disorders including depression. Ghrelin exhibits a dual role through the advancement and reduction of depressive behavior with nervousness in the experimental animals. It modulates depression-related signals by forming neuronal networks with various neuropeptides and classical neurotransmitter systems. The present review emphasizes the integration and signaling of ghrelin with other neuromodulatory systems concerning depressive disorders. The role of ghrelin in the regulation of neurosynaptic transmission and depressive illnesses implies that the ghrelin system modulation can yield promising antidepressive therapies.

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Ghrelin is the orexigenic type of neuropeptide.

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It binds with the growth hormone secretagogue receptor (GHSR).

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GHSR is ubiquitously present in the various brain regions.

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Ghrelin is involved in the regulation of depression-related behavior.

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The review focuses on the neurotransmission and signaling of ghrelin in neuropsychiatric and depressive disorders.

New Insights on the Relationship between Leptin, Ghrelin, and Leptin/Ghrelin Ratio Enforced by Body Mass Index in Obesity and Diabetes

Currently, adipose tissue is considered an endocrine organ, however, there are still many questions regarding the roles of adipokines—leptin and ghrelin being two adipokines. The purpose of the study was to assess the relationship between the adipokines and their ratio with obesity and diabetes. Methods: Sixty patients (mean age 61.88 ± 10.08) were evaluated. Cardiovascular risk factors, leptin, ghrelin, and insulin resistance score values were assessed. The patients were classified according to their body mass index (BMI) as normal weight, overweight, and obese. Results: 20% normal weight, 51.7% overweight, 28.3% obese, and 23.3% diabetic. Obese patients had higher leptin values (in obese 34,360 pg/mL vs. overweight 18,000 pg/mL vs. normal weight 14,350 pg/mL, p = 0.0049) and leptin/ghrelin ratio (1055 ± 641 vs. 771.36 ± 921 vs. 370.7 ± 257, p = 0.0228). Stratifying the analyses according to the presence of obesity and patients’ gender, differences were found for leptin (p = 0.0020 in women, p = 0.0055 in men) and leptin/ghrelin ratio (p = 0.048 in women, p = 0.004 in men). Mean leptin/BMI and leptin/ghrelin/BMI ratios were significantly higher, and the ghrelin/BMI ratio was significantly lower in obese and diabetic patients. In conclusion, obesity and diabetes are associated with changes not only in the total amount but also in the level of adipokines/kg/m². Changes appear even in overweight subjects, offering a basis for early intervention in diabetic and obese patients.

Understanding insomnia as systemic disease

Sleep plays a critical role in homeostasis of the body and mind. Insomnia is a disease that causes disturbances in the initiation and maintenance of sleep. Insomnia is known to affect not only the sleep process itself but also an individual’s cognitive function and emotional regulation during the daytime. It increases the risk of various neuropsychiatric diseases such as depression, anxiety disorder, and dementia. Although it might appear that insomnia only affects the nervous system, it is also a systemic disease that affects several aspects of the body, such as the cardiovascular, endocrine, and immune systems; therefore, it increases the risk of various diseases such as hypertension, diabetes mellitus, and infection. Insomnia has a wide range of effects on our bodies because sleep is a complex and active process. However, a high proportion of patients with insomnia do not seek treatment, which results in high direct and indirect costs. This is attributed to the disregard of many of the negative effects of insomnia. Therefore, we expect that understanding insomnia as a systemic disease will provide an opportunity to understand the condition better and help prevent secondary impairment due to insomnia.

Association between sleep quality and type 2 diabetes at 20-year follow-up in the Southall and Brent REvisited (SABRE) cohort: a triethnic analysis

Background

The risk of developing type 2 diabetes associated with poor sleep quality is comparable to other lifestyle factors (eg, overweight, physical inactivity). In the UK, these risk factors could not explain the two to three-fold excess risks in South-Asian and African-Caribbean men compared with Europeans. This study investigates (1) the association between mid-life sleep quality and later-life type 2 diabetes risk and (2) the potential modifying effect of ethnicity.

Methods

The Southall and Brent REvisited cohort is composed of Europeans, South-Asians and African-Caribbeans (median follow-up 19 years). Complete-case analysis was performed on 2189 participants without diabetes at baseline (age=51.7±7 SD). Competing risks regressions were used to estimate the HRs of developing diabetes associated with self-reported baseline sleep (difficulty falling asleep, early morning waking, waking up tired, snoring and a composite sleep score), adjusting for confounders. Modifying effects of ethnicity were analysed by conducting interaction tests and ethnicity-stratified analyses.

Results

There were 484 occurrences of incident type 2 diabetes (22%). Overall, there were no associations between sleep exposures and diabetes risk. Interaction tests suggested a possible modifying effect for South-Asians compared with Europeans for snoring only (p=0.056). The ethnicity-stratified analysis found an association with snoring among South-Asians (HR 1.41, 95% CI 1.08 to 1.85), comparing those who snored often/always versus occasionally/never. There were no elevated risks for the other sleep exposures.

Conclusion

The association between snoring and type 2 diabetes appeared to be modified by ethnicity, and was strongest in South-Asians.

Effects of Ramadan intermittent fasting on leptin and adiponectin: a systematic review and meta-analysis

OBJECTIVES

Ramadan intermittent fasting may affect whole-body metabolism by affecting appetite-related hormones. This systematic review and meta-analysis aimed to clarify the possible effects of Ramadan intermittent fasting on the main hormones regulating appetite and satiety, including leptin and adiponectin.

METHODS

All English language papers in the PubMed, Scopus, and Embase databases were searched using the keywords "Ramadan fasting", "adiponectin", and "leptin", up to 2020. Data extraction was conducted based on the main data of the studies; the primary outcomes of the analysis were mean changes of adiponectin and leptin levels during the holy month of Ramadan in fasted subjects.

MAIN RESULTS

Data of 16 eligible studies, conducted between 2003 and 2020, were included in the systematic review. Of these, 10 studies with complete data on leptin and adiponectin were included in the meta-analysis. A significant decrease in leptin levels was observed after Ramadan fasting (WMD = -2.28 ng/ml, 95% CI = -3.72, -0.84). Ramadan fasting had no significant effect on adiponectin levels (WMD = 2.19 ng/ml, 95% CI = -0.29, 4.67). Sub-group analysis demonstrated a greater decrease in leptin levels among normal-weight subjects compared to those of overweight/obese subjects (WMD = -4.67 ng/ml, 95% CI = -6.03, -3.31 vs. WMD = -3.43 ng/ml, 95% CI = -5.69, -1.17).

CONCLUSION

Ramadan fasting may decrease leptin levels, especially in normal-weight subjects. There was high heterogeneity, which may be explained by the differences between the wide ranges of study conditions.

The case for investigating a bidirectional association between insomnia symptoms and eating disorder pathology

Many people with eating disorders (EDs) report symptoms of insomnia (i.e., frequent difficulty falling asleep, staying asleep, and/or early morning wakening) and sleep problems have been linked to alterations in eating behaviors; however, mechanisms of these bidirectional associations remain poorly understood and under researched. This is a problem because higher insomnia symptom severity is a risk factor for the onset and perpetuation of anxiety, mood, trauma, and substance use disorders and, potentially, ED symptoms. Furthermore, insomnia symptoms may hinder recovery and increase relapse rates following successful psychotherapy. In this article, we describe potential mechanisms underlying bidirectional associations between insomnia and eating psychopathology that may contribute to the etiology and maintenance of both disorders. We suggest novel directions for future research to characterize the association between dysregulated sleep and ED symptoms and to evaluate impacts of insomnia symptoms on relapse and recovery for people with co-occurring pathology. Finally, we discuss options for testing the incorporation of existing evidence-based treatments for insomnia disorder (e.g., Cognitive-Behavioral Therapy for Insomnia) with ED care. Overall, insomnia symptoms present a promising intervention point for ED treatment that has not been systematically tested, yet would be highly feasible to address in routine clinical care.

The Role of Sleep Curtailment on Leptin Levels in Obesity and Diabetes Mellitus

Emerging evidence has identified sleep as a significant, but modifiable, risk factor for metabolic syndrome, diabetes, and obesity. Leptin, an adipocyte-derived peptide and a regulator of food intake and energy expenditure, has been shown to be associated with a short sleep duration in the pathophysiology of obesity and consequently type 2 diabetes. This review focuses on the current evidence indicating the effects of a short sleep duration on the regulation of leptin concentration in association with obesity and diabetes mellitus. In summary, the evidence suggests that sleep deprivation, by affecting leptin regulation, may lead to obesity and consequently development of type 2 diabetes through increased appetite and food intake. However, findings on the role of leptin in diabetes due to sleep deprivation are contradictory, and further studies with larger sample sizes are needed to confirm previous findings.

The effect of sleep deficiency on esophageal acid exposure of healthy controls and patients with gastroesophageal reflux disease

BACKGROUND

Studies have demonstrated a bi-directional relationship between sleep deficiency and gastroesophageal reflux disease (GERD). However, there is limited data on how sleep deficiency affects esophageal acid exposure. We aimed to compare the effect of sleep deficiency on esophageal acid exposure of healthy controls versus GERD patients.

METHODS

Eleven patients from each of 2 groups were randomized to undergo pH-testing after 2 consecutive days of 7-8 hours of sleep per night (normal sleep) or 2 consecutive days of 4 hours of sleep per night (deficient sleep). All subjects then crossed over to the other arm, after 1-week washout period. While subjects were instructed to follow the study sleep protocol, actigraphy ensured subjects followed required sleeping time during study period.

KEY RESULTS

After normal sleep, all healthy controls had normal esophageal acid exposure. After deficient sleep, 5 healthy controls demonstrated an abnormal pH test. Overall, there was a significant increase in reflux parameters after deficient sleep as compared with normal sleep (% total time-6.15 ± 5.89 vs 1.74 ± 1.54, % upright time-4.72 ± 5.36 vs 0.87 ± 1.28, P < .05, respectively). After normal sleep, 6 GERD patients (54.5%) demonstrated an abnormal pH-testing. After deficient sleep, 10 GERD patients (90.9%) demonstrated an abnormal pH-testing. GERD patients demonstrated significantly higher reflux parameters than healthy controls after normal sleep (% total time-5.02 ± 3.45 vs 1.74 ± 1.54, % upright time-4.11 ± 3.98 vs 0.87 ± 1.28, P < .05, respectively).

CONCLUSIONS & INFERENCES

Sleep deficiency increased esophageal acid exposure in both healthy controls and GERD patients. Sleep deficiency also resulted in abnormal pH tests in almost half of healthy controls.

Obsessive-compulsive disorder and growth factors: A comparative review

The goal of this article is to clarify the role of various growth factors in the establishment and progression of obsessive-compulsive disorder (OCD). OCD is a chronic mental disorder with recurrent intrusive thoughts and/or repetitive compulsive behaviors that increase during stressful periods. Growth and neurotrophic factors may be contributing factors in the pathophysiology of OCD. Many of them are synthesized and released within the central nervous system and act as trophic agents in neurons; some of them are involved in brain growth, development, neurogenesis, myelination and plasticity, while others take part in the protection of the nervous system following brain injuries. This paper attempts to identify all articles investigating the relationship between OCD and neurotrophic and growth factors, in both animal and human studies, with a focus on adult brain studies. Based on the PubMed and Scopus and Science Direct search tools, the available articles and studies are reviewed. Out of 230 records in total, the ones related to our review topic were taken into account to further understand the pathophysiological mechanism(s) of OCD, providing methods to improve its symptoms via the modification of neurotrophins and growth factor imbalances.

Association between sleep quality and metabolic syndrome: A systematic review and meta-analysis

Sleep quality has been suggested to play an important role in development of metabolic syndrome (MetS). However, the results have been inconsistent. A systematic review of observational studies aimed to evaluate the association between sleep quality and MetS. A comprehensive search was conducted in PubMed and EMBASE. The pooled odd ratios (ORs) were calculated using random effects models. The construction of funnel plot was used to explore publication bias, with further application of Egger's test. 22 studies were included. The pooled finding showed that overall sleep quality had a significant positive association with MetS (OR 1.37, 95% CI 1.15-1.64), with substantial heterogeneity (I² = 62.4%, P < 0.1). Similarly, the complaints of sleep, including difficulty in falling sleep (OR 1.18, 95% CI 1.05-1.33), difficulty in maintaining sleep (OR 1.15, 95% CI 1.02-1.30) and sleep inefficiency (OR 1.40, 95% CI 1.04-1.89) were proved to be associated with the risk of MetS. Our results indicated the overall sleep quality as well as sleep complaints have significant positive associations with MetS. Further studies based on a longitudinal design using validated tools that measure both objective and subjective components of sleep quality are needed to explore the causal relationship between sleep quality and MetS.

Stress and Systemic Inflammation: Yin-Yang Dynamics in Health and Diseases

Studies in psychoneuroimmunology (PNI) would provide better insights into the "whole mind-body system." Systems biology models of the complex adaptive systems (CASs), such as a conceptual framework of "Yin-Yang dynamics," may be helpful for identifying systems-based biomarkers and targets for more effective prevention and treatment. The disturbances in the Yin-Yang dynamical balance may result in stress, inflammation, and various disorders including insomnia, Alzheimer's disease, obesity, diabetes, cardiovascular diseases, skin disorders, and cancer. At the molecular and cellular levels, the imbalances in the cytokine pathways, mitochondria networks, redox systems, and various signaling pathways may contribute to systemic inflammation. In the nervous system, Yin and Yang may represent the dynamical associations between the progressive and regressive processes in aging and neurodegenerative diseases. In response to the damages to the heart, the Yin-Yang dynamical balance between proinflammatory and anti-inflammatory cytokine networks is crucial. The studies of cancer have revealed the importance of the Yin-Yang dynamics in the tumoricidal and tumorigenic activities of the immune system. Stress-induced neuroimmune imbalances are also essential in chronic skin disorders including atopic dermatitis and psoriasis. With the integrative framework, the restoration of the Yin-Yang dynamics can become the objective of dynamical systems medicine.

Pharmacological manipulation of the ghrelin system and alcohol hangover symptoms in heavy drinking individuals: Is there a link?

Ghrelin, an orexigenic peptide synthesized in the stomach, is a key player in the gut-brain axis. In addition to its role in regulating food intake and energy homeostasis, ghrelin has been shown to modulate alcohol-related behaviors. Alcohol consumption frequently results in hangover, an underexplored phenomenon with considerable medical, psychological, and socioeconomic consequences. While the pathophysiology of hangover is not clear, contributions of mechanisms such as alcohol-induced metabolic/endocrine changes, inflammatory/immune response, oxidative stress, and gut dysbiosis have been reported. Interestingly, these mechanisms considerably overlap with ghrelin's physiological functions. Here, we investigated whether pharmacological manipulation of the ghrelin system may affect alcohol hangover symptoms. Data were obtained from two placebo-controlled laboratory studies. The first study tested the effects of intravenous (IV) ghrelin and consisted of two experiments: a progressive-ratio IV alcohol self-administration (IV-ASA) and a fixed-dose IV alcohol clamp. The second study tested the effects of an oral ghrelin receptor inverse agonist (PF-5190457) and included a fixed-dose oral alcohol administration experiment. Alcohol hangover data were collected the morning after each alcohol administration experiment using the Acute Hangover Scale (AHS). IV ghrelin, compared to placebo, significantly reduced alcohol hangover after IV-ASA (p = 0.04) and alcohol clamp (p = 0.04); PF-5190457 had no significant effect on AHS scores. Females reported significantly higher hangover symptoms than males following the IV-ASA experiment (p = 0.04), but no gender × drug condition (ghrelin vs. placebo) effect was found. AHS total scores were positively correlated with peak subjective responses, including 'stimulation' (p = 0.08), 'sedation' (p = 0.009), 'feel high' (p = 0.05), and 'feel intoxicated' (p = 0.03) during the IV-ASA. IV ghrelin blunted the positive association between alcohol sedation and hangover as shown by trend-level drug × sedation effect (p = 0.08). This is the first study showing that exogenous ghrelin administration, but not ghrelin receptor inverse agonism, affects hangover symptoms. Future research should investigate the potential mechanism(s) underlying this effect.

Sleep and Obesity

Rising global prevalence and incidence of obesity lead to increased cardiovascular-renal complications and cancers. Epidemiological studies reported a worldwide trend towards suboptimal sleep duration and poor sleep quality in parallel with this obesity epidemic. From rodents and human models, it is highly plausible that abnormalities in sleep, both quantity and quality, impact negatively on energy metabolism. While excess dietary intake and physical inactivity are the known drivers of the obesity epidemic, promotion of healthy sleep habits has emerged as a new target to combat obesity. In this light, present review focuses on the existing literature examining the relationship between sleep physiology and energy homeostasis. Notably, sleep dysregulation perturbs the metabolic milieu via alterations in hormones such as leptin and ghrelin, eating behavior, neuroendocrine and autonomic nervous systems. In addition, shift work and trans-meridian air travel may exert a negative influence on the hypothalamic-pituitary-adrenal axis and trigger circadian misalignment, leading to impaired glucose tolerance and increased fat accumulation. Amassing evidence has also suggested that uncoupling of the circadian clock can increase the risk of adverse metabolic health. Given the importance of sleep in maintaining energy homeostasis and that it is potentially modifiable, promoting good sleep hygiene may create new avenues for obesity prevention and treatment.

Menopause status is associated with circadian- and sleep-related alterations

OBJECTIVE

The aim of the study was to investigate whether postmenopausal women show differences in circadian-related variables and sleep characteristics compared with premenopausal women, and to analyze potential associations between these circadian-related variables and abdominal fat distribution or metabolic syndrome (MetS) components.

METHODS

A total of 177 women were studied (127 premenopausal, 50 postmenopausal). Sixty percent of the total population was overweight/obese, with no significant differences between premenopausal (60%) and postmenopausal women (62%) (P = 0.865). Wrist temperature (WT) and rest-activity cycles were measured during 8 consecutive days, and sleep and food diaries collected. MetS characteristics and daily patterns of saliva cortisol were analyzed. Sleep characteristics were assessed with domiciliary polysomnography.

RESULTS

Postmenopausal women showed a less robust rhythm in WT with lower amplitude (°C) (0.8 ± 0.4 vs 0.9 ± 0.5) (P < 0.05) and lower mean temperature values at the midpoint of sleep than premenopausal women. Postmenopausal women were also more morning-type than premenopausal women, showing a phase advance of approximately 1 hour in WT and rest-activity rhythms, and more morning-type habits (earlier sleep onset/offset and breakfast intake) (P < 0.05). Postmenopausal women showed higher levels of activity in the morning and lower in the evening compared with premenopausal women (P < 0.05). Daily variability in cortisol was significantly reduced in postmenopausal women compared with premenopausal women (P < 0.05). Postmenopausal women had increased frequency of sleep-related breathing abnormalities (P < 0.0001). In the women studied, abdominal fat and MetS were associated with an increase in circadian alterations (high fragmentation and low amplitude of the rhythm) (P < 0.05).

CONCLUSIONS

Postmenopausal women exhibit loss of circadian robustness and an increase in sleep abnormalities compared with premenopausal women.

Sleep Duration and Diabetes Risk: Population Trends and Potential Mechanisms

Sleep is important for regulating many physiologic functions that relate to metabolism. Because of this, there is substantial evidence to suggest that sleep habits and sleep disorders are related to diabetes risk. In specific, insufficient sleep duration and/or sleep restriction in the laboratory, poor sleep quality, and sleep disorders such as insomnia and sleep apnea have all been associated with diabetes risk. This research spans epidemiologic and laboratory studies. Both physiologic mechanisms such as insulin resistance, decreased leptin, and increased ghrelin and inflammation and behavioral mechanisms such as increased food intake, impaired decision-making, and increased likelihood of other behavioral risk factors such as smoking, sedentary behavior, and alcohol use predispose to both diabetes and obesity, which itself is an important diabetes risk factor. This review describes the evidence linking sleep and diabetes risk at the population and laboratory levels.

Insomnia and obesity

PURPOSE OF REVIEW

Accumulating data suggest that short sleep plays a role in the development of obesity in general population. Insomnia disorder is characterized by short sleep and may persist for years. The question whether these patients have a higher risk of obesity is of socioeconomic as well as therapeutic interest.

RECENT FINDINGS

Numerous recently published cross-sectional and longitudinal studies show positive as well as negative associations between short sleep and overweight. Critical reviews note several methodological limitations that weaken the assumption of short sleep duration as the potential cause for obesity. From a sleep medical perspective, a basic methodological problem is the lack of a biological cut-off for short sleep duration. Therefore, recent findings on the relation between emotional stress in short sleepers and incident of obesity opens a more promising perspective on sleep quality as a possible factor. A few studies on patients with insomnia disorder, however, do not show higher BMIs adding data to a research puzzle.

SUMMARY

The relation of sleep duration and incident obesity so far has insufficient evidence base. Few data on patients with insomnia disorder do not confirm the association. Further research is necessary with focus on sleep quality instead of sleep duration.

Pharmacokinetics and pharmacodynamics of PF-05190457: The first oral ghrelin receptor inverse agonist to be profiled in healthy subjects

AIM

To evaluate safety, tolerability and pharmacokinetics of oral PF-05190457, an oral ghrelin receptor inverse agonist, in healthy adults.

METHODS

Single (SAD) and multiple ascending dose (MAD) studies were randomised, placebo-controlled, double-blind studies. Thirty-five healthy men (age 38.2 ± 10.4 years; body mass index 24.8 ± 3.1 kg m^-2 [mean ± standard deviation]) received ≥1 dose (2, 10, 40 [divided], 50, 100, 150, and 300 [single or divided] mg) of PF-05190457 and/or placebo in the SAD. In the MAD study, 35 healthy men (age 39.7 ± 10.1 years; body mass index 25.9 ± 3.3 kg m^-2 ) received ≥1 dose (2, 10, 40 and 100 mg twice daily) of PF-05190457 and/or placebo daily for 2 weeks.

RESULTS

PF-05190457 absorption was rapid with a T_max of 0.5-3 hours and a half-life between 8.2-9.8 hours. PF-05190457 dose-dependently blocked ghrelin (1 pmol kg^-1  min^-1 )-induced growth hormone (GH) release with (mean [90% confidence interval]) 77% [63-85%] inhibition at 100 mg. PF-05190457 (150 mg) delayed gastric emptying lag time by 30% [7-58%] and half emptying time by 20% [7-35%] with a corresponding decrease in postprandial glucose by 9 mg dL^-1 . The most frequent adverse event reported by 30 subjects at doses ≥50 mg was somnolence. PF-05190457 plasma concentrations also increased heart rate up to 13.4 [4.8-58.2] beats min^-1 and, similar to the effect on glucose and ghrelin-induced GH, was lost within 2 weeks.

CONCLUSIONS

PF-05190457 is a well-tolerated first-in-class ghrelin receptor inverse agonist with acceptable pharmacokinetics for oral daily dosing. Blocking ghrelin receptors inhibits ghrelin-induced GH, and increases heart rate, effects that underwent tachyphylaxis with chronic dosing. PF-051940457 has the potential to treat centrally-acting disorders such as insomnia.

Bright versus dim ambient light affects subjective well-being but not serotonin-related biological factors

Light falling on the retina is converted into an electrical signal which stimulates serotonin synthesis. Previous studies described an increase of plasma and CNS serotonin levels after bright light exposure. Ghrelin and leptin are peptide hormones which are involved in the regulation of hunger/satiety and are related to serotonin. Neopterin and kynurenine are immunological markers which are also linked to serotonin biosynthesis. In this study, 29 healthy male volunteers were exposed to bright (5000lx) and dim (50lx) light conditions for 120min in a cross-over manner. Subjective well-being and hunger as well as various serotonin associated plasma factors were assessed before and after light exposure. Subjective well-being showed a small increase under bright light and a small decrease under dim light, resulting in a significant interaction between light condition and time. Ghrelin concentrations increased significantly under both light conditions, but there was no interaction between light and time. Correspondingly, leptin decreased significantly under both light conditions. Hunger increased significantly with no light-time interaction. We also found a significant decrease of neopterin, tryptophan and tyrosine levels, but no interaction between light and time. In conclusion, ambient light was affecting subjective well-being rather than serotonin associated biological factors.

Ghrelin in psychiatric disorders - A review

Ghrelin is a 28-amino-acid peptide hormone, first described in 1999 and broadly expressed in the organism. As the only known orexigenic hormone secreted in the periphery, it increases hunger and appetite, promoting food intake. Ghrelin has also been shown to be involved in various physiological processes being regulated in the central nervous system such as sleep, mood, memory and reward. Accordingly, it has been implicated in a series of psychiatric disorders, making it subject of increasing investigation, with knowledge rapidly accumulating. This review aims at providing a concise yet comprehensive overview of the role of ghrelin in psychiatric disorders. Ghrelin was consistently shown to exert neuroprotective and memory-enhancing effects and alleviated psychopathology in animal models of dementia. Few human studies show a disruption of the ghrelin system in dementia. It was also shown to play a crucial role in the pathophysiology of addictive disorders, promoting drug reward, enhancing drug seeking behavior and increasing craving in both animals and humans. Ghrelin's exact role in depression and anxiety is still being debated, as it was shown to both promote and alleviate depressive and anxiety-behavior in animal studies, with an overweight of evidence suggesting antidepressant effects. Not surprisingly, the ghrelin system is also implicated in eating disorders, however its exact role remains to be elucidated. Its widespread involvement has made the ghrelin system a promising target for future therapies, with encouraging findings in recent literature.

Associations between Poor Sleep Quality and Stages of Change of Multiple Health Behaviors among Participants of Employee Wellness Program

OBJECTIVE

Using the Transtheoretical Model of behavioral change, this study evaluates the relationship between sleep quality and the motivation and maintenance processes of healthy behavior change.

METHODS

The current study is an analysis of data collected in 2008 from an online health risk assessment (HRA) survey completed by participants of the Kansas State employee wellness program (N=13,322). Using multinomial logistic regression, associations between self-reported sleep quality and stages of change (i.e. precontemplation, contemplation, preparation, action, maintenance) in five health behaviors (stress management, weight management, physical activities, alcohol use, and smoking) were analyzed.

RESULTS

Adjusted for covariates, poor sleep quality was associated with an increased likelihood of contemplation, preparation, and in some cases action stage when engaging in the health behavior change process, but generally a lower likelihood of maintenance of the healthy behavior.

CONCLUSIONS

The present study demonstrated that poor sleep quality was associated with an elevated likelihood of contemplating or initiating behavior change, but a decreased likelihood of maintaining healthy behavior change. It is important to include sleep improvement as one of the lifestyle management interventions offered in EWP to comprehensively reduce health risks and promote the health of a large employee population.

Polysomnographically determined sleep and body mass index in patients with insomnia

We assessed associations between polysomnographically determined sleep, especially the amount of slow-wave sleep (SWS), and body mass index (BMI) in patients with insomnia. One hundred and forty-one insomniacs and 55 healthy volunteers completed overnight polysomnographic recordings, and we measured height and body weight. No significant correlations were obtained between total sleep time and BMI among insomniacs. Compared with normal volunteers, insomnia patients exhibited longer sleep latency and shorter total sleep duration. While the two groups had no significant differences in BMI, insomniacs presented with more N1 but less time spend in SWS and rapid eye movement sleep (REMS). Based on their SWS time, we divided insomnia patients into three groups: short (26.99±13.88), intermediate (59.24±8.12), and long (102.21±26.17) SWS groups. The short-SWS group had significantly greater BMI than the long-SWS group. Further analyses with multiple linear regression showed a significant negative correlation between the amount of SWS and BMI scores in insomniacs, whereas no such correlation was found in healthy volunteers after controlling for potential confounds (e.g., age, sex and AHI). Our study suggests that low amounts of SWS may be associated with higher BMI in patients with insomnia.

Skipping breakfast: morningness-eveningness preference is differentially related to state and trait food cravings

Eveningness preference is associated with unhealthy eating behaviors. We measured state and trait food cravings in chronotypes in the morning and in the evening. Less Evening (E)- than Morning (M)-types reported to have had breakfast. Accordingly, hours that had elapsed since the last meal were higher in E- than M-types in the morning, but did not differ between groups in the evening. E-types reported higher anticipation of positive reinforcement that may result from eating than M-types in the morning, but both had the same hunger levels. On a trait level, M-types reported more feelings of guilt for giving into cravings compared to E-types. Results suggest that E-types skip breakfast more often than M-types, but this eating pattern does not inevitably lead to more food cravings in the evening or more pronounced habitual cravings. Furthermore, E-types did not experience more hunger in the morning although they had not been eating for a longer time period. Results support findings about a different lifestyle in E-types compared to M-types.

Rapid modulation of TRH and TRH-like peptide release in rat brain and peripheral tissues by ghrelin and 3-TRP-ghrelin

Ghrelin is not only a modulator of feeding and energy expenditure but also regulates reproductive functions, CNS development and mood. Obesity and major depression are growing public health concerns which may derive, in part, from dysregulation of ghrelin feedback at brain regions regulating feeding and mood. We and others have previously reported that thyrotropin-releasing hormone (TRH, pGlu-His-Pro-NH(2)) and TRH-like peptides (pGlu-X-Pro-NH(2), where "X" can be any amino acid residue) have neuroprotective, antidepressant, anti-epileptic, analeptic, anti-ataxic, and anorectic properties. For this reason male Sprague-Dawley rats were injected ip with 0.1mg/kg rat ghrelin or 0.9mg/kg 3-Trp-rat ghrelin. Twelve brain regions: cerebellum, medulla oblongata, anterior cingulate, posterior cingulate, frontal cortex, nucleus accumbens, hypothalamus, entorhinal cortex, hippocampus, striatum, amygdala, piriform cortex and 5 peripheral tissues (adrenals, testes, epididymis, pancreas and prostate) were analyzed. Rapid and profound decreases in TRH and TRH-like peptide levels (increased release) occurred throughout brain and peripheral tissues following ip ghrelin. Because ghrelin is rapidly deacylated in vivo we also studied 3-Trp-ghrelin which cannot be deacylated. Significant increases in TRH and TRH-like peptide levels following 3-Trp-ghrelin, relative to those after ghrelin were observed in all brain regions except posterior cingulate and all peripheral tissues except prostate and testis. The rapid stimulation of TRH and TRH-like peptide release by ghrelin in contrast with the inhibition of such release by 3-Trp-TRH is consistent with TRH and TRH-like peptides modulating the downstream effects of both ghrelin and unacylated ghrelin.

Interacting epidemics? Sleep curtailment, insulin resistance, and obesity

In the last 50 years, the average self-reported sleep duration in the United States has decreased by 1.5-2 hours in parallel with an increasing prevalence of obesity and diabetes. Epidemiological studies and meta-analyses report a strong relationship between short or disturbed sleep, obesity, and abnormalities in glucose metabolism. This relationship is likely to be bidirectional and causal in nature, but many aspects remain to be elucidated. Sleep and the internal circadian clock influence a host of endocrine parameters. Sleep curtailment in humans alters multiple metabolic pathways, leading to more insulin resistance, possibly decreased energy expenditure, increased appetite, and immunological changes. On the other hand, psychological, endocrine, and anatomical abnormalities in individuals with obesity and/or diabetes can interfere with sleep duration and quality, thus creating a vicious cycle. In this review, we address mechanisms linking sleep with metabolism, highlight the need for studies conducted in real-life settings, and explore therapeutic interventions to improve sleep, with a potential beneficial effect on obesity and its comorbidities.

Need for early interventions in the prevention of pediatric overweight: a review and upcoming directions

Childhood obesity is currently one of the most prevailing and challenging public health issues among industrialized countries and of international priority. The global prevalence of obesity poses such a serious concern that the World Health Organization (WHO) has described it as a "global epidemic." Recent literature suggests that the genesis of the problem occurs in the first years of life as feeding patterns, dietary habits, and parental feeding practices are established. Obesity prevention evidence points to specific dietary factors, such as the promotion of breastfeeding and appropriate introduction of nutritious complementary foods, but also calls for attention to parental feeding practices, awareness of appropriate responses to infant hunger and satiety cues, physical activity/inactivity behaviors, infant sleep duration, and family meals. Interventions that begin at birth, targeting multiple factors related to healthy growth, have not been adequately studied. Due to the overwhelming importance and global significance of excess weight within pediatric populations, this narrative review was undertaken to summarize factors associated with overweight and obesity among infants and toddlers, with focus on potentially modifiable risk factors beginning at birth, and to address the need for early intervention prevention.

Light modulates leptin and ghrelin in sleep-restricted adults

Acute and chronic sleep restrictions cause a reduction in leptin and an increase in ghrelin, both of which are associated with hunger. Given that light/dark patterns are closely tied to sleep/wake patterns, we compared, in a within-subjects study, the impact of morning light exposures (60 lux of 633-nm [red], 532-nm [green], or 475-nm [blue] lights) to dim light exposures on leptin and ghrelin concentrations after subjects experienced 5 consecutive days of both an 8-hour (baseline) and a 5-hour sleep-restricted schedule. In morning dim light, 5-hour sleep restriction significantly reduced leptin concentrations compared to the baseline, 8-hour sleep/dim-light condition (t(1,32) = 2.9; P = 0.007). Compared to the 5-hour sleep/dim-light condition, the red, green, and blue morning light exposures significantly increased leptin concentrations (t(1,32) = 5.7; P < 0.0001, t(1,32) = 3.6; P = 0.001, and t(1,32) = 3.0; P = 0.005, resp.). Morning red light and green light exposures significantly decreased ghrelin concentrations (t(1,32) = 3.3; P < 0.003 and t(1,32) = 2.2; P = 0.04, resp.), but morning blue light exposures did not. This study is the first to demonstrate that morning light can modulate leptin and ghrelin concentrations, which could have an impact on reducing hunger that accompanies sleep deprivation.

Differences in daily rhythms of wrist temperature between obese and normal-weight women: associations with metabolic syndrome features

The circadian rhythm of core body temperature is associated with widespread physiological effects. However, studies with other more practical temperature measures, such as wrist (WT) and proximal temperatures, are still scarce. The aim of this study was to investigate whether obesity is associated with differences in mean WT values or in its daily rhythmicity patterns. Daily patterns of cortisol, melatonin, and different metabolic syndrome (MetS) features were also analyzed in an attempt to clarify the potential association between chronodisruption and MetS. The study was conducted on 20 normal-weight women (age: 38 ± 11 yrs and BMI: 22 ± 2.6 kg/m(2)) and 50 obese women (age: 42 ± 10 yrs and BMI: 33.5 ± 3.2 kg/m(2)) (mean ± SEM). Skin temperature was measured over a 3-day period every 10 min with the "Thermochron iButton." Rhythmic parameters were obtained using an integrated package for time-series analysis, "Circadianware." Obese women displayed significantly lower mean WT (34.1°C ± 0.3°C) with a more flattened 24-h pattern, a lower-quality rhythm, and a higher intraday variability (IV). Particularly interesting were the marked differences between obese and normal-weight women in the secondary WT peak in the postprandial period (second-harmonic power [P2]), considered as a marker of chronodisruption and of metabolic alterations. WT rhythmicity characteristics were related to MetS features, obesity-related proteins, and circadian markers, such as melatonin. In summary, obese women displayed a lower-quality WT daily rhythm with a more flattened pattern (particularly in the postprandial period) and increased IV, which suggests a greater fragmentation of the rest/activity rhythm compared to normal-weight women. These 24-h changes were associated with higher MetS risk.

Sleep disturbances and depressed mood: a harmful combination associated with increased leptin levels in women with normal weight

Leptin, involved in energy regulation and contributor to cardiovascular disease, has been implicated to play a role in depression and sleep disturbances, two closely intertwined conditions. Previous results investigating leptin level alterations either in sleep disorders or in depression have been inconsistent. We investigate the association between leptin levels and the different combinations of depressed mood and sleep disturbances in 1369 subjects (706 men, 663 women), derived from the population-based MONIKA/KORA study. As leptin regulation is known to differ by sex and weight, analyses were performed in normal weight and overweight men and women separately. We found a highly significant association between leptin levels and the combination of depressed mood and sleep disturbances in normal-weight women (BMI ≤ 25) (p<0.01). No associations were found in men and in overweight women. Our results suggest that leptin regulation in depressed mood and sleep disturbances very much depend on sex and weight.

Correlation of shift work and waist circumference, body mass index, chronotype and depressive symptoms

OBJECTIVE

Correlate shift work with body mass index (BMI), waist circumference, chronotype and depressive symptoms.

SUBJECTS AND METHODS

This study comprising 14 shift workers and 13 day workers. Subjects were workers from the health area aged 25 to 60 years. Minor psychiatric disorders were accessed by Self Report Questionnaire (SRQ-20) and depressive symptoms by Beck Depression Inventory (BDI). Chronotype was accessed using Morningness-Eveningness Questionnaire (MEQ). Anthropometric measures were taken.

RESULTS

Shift workers presented higher BMI (P = 0.03) and waist circumference (P = 0.004) than day workers. Years on shift work were significantly correlated to waist circumference (r = 0.43; P = 0.03) and age (r = 0.47; P = 0.02). Shift work was not correlated with depressive symptoms and chronotype.

CONCLUSION

These results may suggest a role played by shift work on the development and/or the early clinic manifestations of metabolic disturbances, becoming a risk factor to metabolic syndrome.

Ghrelin in mental health, sleep, memory

Ghrelin acts as a neuropeptide. It participates in sleep-wake regulation. After systemic ghrelin treatment nonREM sleep is promoted in male humans and mice. This effect is influenced by gender, time of administration and depression. Ghrelin does not modulate sleep in healthy women and during the early morning in male subjects. In depressed women REM sleep is diminished after ghrelin. In elderly men and depressed men sleep promotion by ghrelin was preserved. In rats after central ghrelin feeding and wakefulness increased. The nocturnal secretion pattern of cortisol, GH, LH, FSH and hypothalamo-pituitary-thyroid hormones are influenced by ghrelin. Furthermore ghrelin appears to be related to memory and to be involved in the pathophysiology of CNS disorders, particularly depression.

Endocrine factors in the hypothalamic regulation of food intake in females: a review of the physiological roles and interactions of ghrelin, leptin, thyroid hormones, oestrogen and insulin

Controlling energy homeostasis involves modulating the desire to eat and regulating energy expenditure. The controlling machinery includes a complex interplay of hormones secreted at various peripheral endocrine endpoints, such as the gastrointestinal tract, the adipose tissue, thyroid gland and thyroid hormone-exporting organs, the ovary and the pancreas, and, last but not least, the brain itself. The peripheral hormones that are the focus of the present review (ghrelin, leptin, thyroid hormones, oestrogen and insulin) play integrated regulatory roles in and provide feedback information on the nutritional and energetic status of the body. As peripheral signals, these hormones modulate central pathways in the brain, including the hypothalamus, to influence food intake, energy expenditure and to maintain energy homeostasis. Since the growth of the literature on the role of various hormones in the regulation of energy homeostasis shows a remarkable and dynamic expansion, it is now becoming increasingly difficult to understand the individual and interactive roles of hormonal mechanisms in their true complexity. Therefore, our goal is to review, in the context of general physiology, the roles of the five best-known peripheral trophic hormones (ghrelin, leptin, thyroid hormones, oestrogen and insulin, respectively) and discuss their interactions in the hypothalamic regulation of food intake.