The Important Role of Adiponectin and Orexin-A, Two Key Proteins Improving Healthy Status: Focus on Physical Activity

Burnout and Stress in Forensic Science Jobs: A Systematic Review

BACKGROUND/OBJECTIVES

Burnout and occupational stress are significant issues among forensic professionals, impacting their well-being and job performance. This systematic review aims to provide an up-to-date overview of the occupational stress and burnout experienced by forensic personnel, exploring the profound and multifaceted impact on their physical, mental, professional, and interpersonal well-being.

METHODS

A systematic review was conducted following PRISMA guidelines using Scopus and WOS databases to search for articles published from 1 January 2000 to 31 August 2024. The search used keywords related to burnout and forensic professions. Inclusion criteria were original articles in English and French, while reviews, book chapters, editorials, and notes were excluded. A total of 10 studies were included after eliminating duplicates and excluding irrelevant articles.

RESULTS

The review identified seven key findings. (1) High levels of occupational stress and burnout among forensic personnel necessitate effective stress management strategies and resilience training; (2) autopsy technicians in Romania experience burnout and alexithymia, particularly related to traumatic events involving children, highlighting the need for specialized support systems; (3) disparities in burnout and post-traumatic stress disorder (PTSD) symptoms were observed in autopsy technicians and resident doctors, suggesting tailored mental health resources; (4) organizational factors, such as peer support and compensation satisfaction, significantly impact burnout and secondary traumatic stress (STS) among sexual assault nurse examiners; (5) burnout among forensic physicians, both in Romania and Egypt, is linked to personality traits, job satisfaction, and socio-demographic factors; (6) pathologists face a range of health issues, including musculoskeletal problems and psychological disorders, underscoring the need for industry-specific health measures; and (7) the lack of wellness resources for forensic professionals calls for improved mental health support and training.

CONCLUSIONS

The findings highlight the pervasive issue of burnout and stress among forensic professionals globally. Addressing these challenges requires comprehensive stress management programs, tailored mental health resources, and organizational support. Future research should focus on developing and implementing effective interventions to enhance resilience and job satisfaction within this high-stress field.

Neurobiology and medico-legal aspects of suicides among older adults: a narrative review

The task of preventing suicide in older adults is an important social burden as older adults aged above 65 are exposed to singular psychological aspects that increase suicide risks. Moreover, when an older adult corpse is found, the medico-legal inspection represents a fundamental tool to identify the exact cause of death, classifying or excluding it as suicide. In this scenario, this review aims to explore the neurobiological factors that could be related to suicidal behavior in older adults. A further goal of this review is the exploration of the medico-legal aspects surrounding older adult suicides, clarifying the importance of forensic investigation. Particularly, this review examines issues such as neurotransmitter imbalances, cognitive impairment, neuroinflammation, psychosocial factors related to geriatric suicide, and neurodegenerative diseases. Additionally, medico-legal aspects such as policy considerations, legal frameworks, mental health assessments, ethical implications and forensic investigation were explored. Considering the importance of this phenomenon, especially in western countries, a need has emerged for focused screening tools on suicidal behavior among older adults, in order to contain it. Therefore, this review makes an exhaustive appraisal of the literature giving insights into the delicate interplay between neurobiology as well as mental health in relation to older adult suicide within a medico-legal context. The comprehension of different aspects about this complex phenomenon is fundamental to propose new and more effective interventions, supporting tailored initiatives such as family support and improving healthcare, specifically towards vulnerable ageing societies to reduce older adult suicide risks.

Integrated neuromuscular training intervention applied in schools induces a higher increase in salivary high molecular weight adiponectin and a more favorable body mass index, cardiorespiratory fitness and muscle strength in children as compared to the traditional physical education classes

Background

High-molecular-weight adiponectin (HMW-adiponectin) is a cardio-metabolic health protector. Objectives: (1) to compare body mass index (BMI), cardiorespiratory fitness (CRF) and muscle strength (MS) in healthy school-children depending on their baseline salivary-HMW-adiponectin concentration; and (2) to apply a 3-month integrated neuromuscular training (INT) and evaluate its effects on salivary-HMW-adiponectin concentration, BMI, CRF and MS in the same children. Additional goal: to identify if any potential changes during the 3-month period may be related to a potential change in salivary-HMW-adiponectin concentration.

Methods

Ninety children (7.4 ± 0.3 years) were recruited in primary schools and randomly allocated into control or intervention group. The intervention consisted of a 3-month INT applied during physical education (PE) classes, twice-weekly, while the control group had traditional PE classes. Body mass and height were measured, BMI was calculated and HMW-adiponectin was quantified in saliva. To assess CRF and MS, 800 m-run and hand-dynamometry were applied, respectively. All measurements were performed twice, at baseline and after 3 months.

Results

Children with higher baseline salivary-HMW-adiponectin have more favorable BMI (p = 0.006) and slightly higher CRF (p = 0.017) in comparison to the children with lower baseline salivary-HMW-adiponectin. There were no big changes after the 3-month-period neither in the control, nor the INT group. However, it is worthy to note that the INT induced slightly higher increase in salivary-HMW-adiponectin (p = 0.007), and a slightly higher improvement in BMI (p = 0.028), CRF (p = 0.043) and MS (p = 0.003), as compared to the traditional PE classes. Finally, the INT-induced improvement in CRF was associated with the increased post-salivary-HMW-adiponectin concentration (p = 0.022).

Conclusion

Main findings may suggest the potential utility of an INT as a cost-effective strategy that can be applied in schools to induce cardio-protective effects in school-children.

Evaluation of Orexin-A Salivary Levels and its Correlation with Attention After Non-invasive Brain Stimulation in Female Volleyball Players

BACKGROUND

The capacity to change attention from one area to another depending on the many environmental circumstances present is a crucial aspect of selective attention and is strictly correlated to reaction time. The cholinergic system of the basal forebrain is crucial for attentive abilities. Several inputs, particularly orexin neurons, whose cell bodies are found in the postero-lateral hypothalamus, can activate the cholinergic system. The aim of this study was to investigate if high frequencies rTMS at dorsolateral prefrontal cortex (DLPFC) in highly trained volleyball players can change Orexin-A levels, attention and reaction time. This study was a double-blinded (participant and evaluator) matched-pair experimental design. Twenty right-handed female volleyball players were recruited for the study (age 24.6 ± 2.7 years; height 177.0 ± 5.5 cm; body mass 67.5 ± 6.5 kg; BMI 21.5 ± 1.2).

RESULTS

The main finding of this study was that 10 Hz rTMS to the DLPFC seems to increase Orexin-A salivary levels and the percentage of correct answers, while decreasing RT. After rTMS, the athletes show an increase in the percentage of correct answers immediately after the end of stimulation, and also after 15 and 30 min. Moreover, the athletes show decreases in reaction time after the end of stimulation and after 15 and 30 min to the end of stimulation, while no differences were found at the end of stimulation. Finally, the athletes show significant increases in Orexin-A salivary levels after stimulation with a peak after 30' of the end.

CONCLUSION

The results of our study seem to indicate that there is a relationship between salivary Orexin-A levels and RT. These results could provide useful tools for modulating sports training; in fact, if confirmed, they could lead coaches to offer their athletes rTMS sessions appropriately integrated with training. In fact, alternating attention is a mental flexibility that enables people to change their point of focus and switch between tasks requiring various levels of cognition.

Adiponectin-mediated regulation of the adiponectin cascade in cardiovascular disease: Updates

The endocrine function of white adipose tissue is characterized by the synthesis of one its main hormones: adiponectin. Although the biological role of adiponectin has not been fully defined, clinical and experimental observations have shown that low plasma concentrations of adiponectin participate in the prevalence of insulin resistance and cardiovascular diseases, mainly in obese patients. Adiponectin also exerts its effects on the heart and blood vessels, thereby influencing their physiology. Studying the effects of adiponectin presents some complexities, primarily due to potential cross-interactions and interference with other pathways, such as the AdipoR1/R2 pathways. Under optimal conditions, the activation of the adiponectin cascade may involve signals such as AMPK and PPARα. Interestingly, these pathways may trigger similar responses, such as fatty acid oxidation. Understanding the downstream effectors of these pathways is crucial to comprehend the extent to which adiponectin signaling impacts metabolism. In this review, the aim is to explore the current mechanisms that regulate the adiponectin pathways. Additionally, updates on the major downstream factors involved in adiponectin signaling are provided, specifically in relation to metabolic syndrome and atherosclerosis.

Acute non invasive brain stimulation improves performances in volleyball players

OBJECTIVES

The ability to redirect one's attention in response to various environmental situations is a crucial aspect of selective attention in team sports. Thus, the aim of this study was to investigate whether repetitive transcranial magnetic stimulation (rTMS) in volleyball players can improve Posner test response and cortical excitability. This study had a double-blinded (participant and evaluator) matched-pair experimental design.

METHODS

Twenty right-handed female volleyball players were recruited for the study and randomly assigned to either the active rTMS group (n = 10) or the sham stimulation group (n = 10). The stimulation was performed in one session with 10 Hz, 80% of the resting motor threshold (RMT), 5 s of stimulation, and 15 s of rest, for a total of 1,500 pulses. Before and after stimulation, the Posner test and cortical excitability were evaluated.

RESULTS

The significant finding of this paper was that 10 Hz rTMS to the DLPFC seemed to improve Posner test response, and also resulted in a significantly decreased RMT and MEP latency of the ipsilateral motor cortex. After stimulation, the active group showed a significant decrease in the percentage of errors in the Posner test. Moreover, active group showed faster RT after rTMS, suggesting that HF stimulation could enhance performance. Additionally, significant differences in RMT emerged in the active rTMS group after stimulation, while no differences were observed in MEP latency and MEP amplitude.

CONCLUSION

In conclusion, we believe that these results may be of great interest to the scientific community and could have practical implications in the future.

360-Degree Perspectives on Obesity

Alarming statistics show that the number of people affected by excessive weight has surpassed 2 billion, representing approximately 30% of the world's population. The aim of this review is to provide a comprehensive overview of one of the most serious public health problems, considering that obesity requires an integrative approach that takes into account its complex etiology, including genetic, environmental, and lifestyle factors. Only an understanding of the connections between the many contributors to obesity and the synergy between treatment interventions can ensure satisfactory outcomes in reducing obesity. Mechanisms such as oxidative stress, chronic inflammation, and dysbiosis play a crucial role in the pathogenesis of obesity and its associated complications. Compounding factors such as the deleterious effects of stress, the novel challenge posed by the obesogenic digital (food) environment, and the stigma associated with obesity should not be overlooked. Preclinical research in animal models has been instrumental in elucidating these mechanisms, and translation into clinical practice has provided promising therapeutic options, including epigenetic approaches, pharmacotherapy, and bariatric surgery. However, more studies are necessary to discover new compounds that target key metabolic pathways, innovative ways to deliver the drugs, the optimal combinations of lifestyle interventions with allopathic treatments, and, last but not least, emerging biological markers for effective monitoring. With each passing day, the obesity crisis tightens its grip, threatening not only individual lives but also burdening healthcare systems and societies at large. It is high time we took action as we confront the urgent imperative to address this escalating global health challenge head-on.

Association of physical activity with increased PI3K and Akt mRNA levels in adipose tissues of obese and non-obese adults

Phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway regulates glucose and lipid metabolism. We examined the association of PI3K and Akt expression in visceral (VAT) and subcutaneous adipose tissue (SAT) with daily physical activity (PA) in non-diabetic obese and non-obese adults. In this cross-sectional study, we included 105 obese (BMI ≥ 30 kg/m²) and 71 non-obese (BMI < 30 kg/m²) subjects (aged/ ≥ 18 years). PA was measured using a valid and reliable International Physical Activity Questionnaire(IPAQ)-long-form, and the metabolic equivalent of task(MET) was calculated. Real-time PCR was performed to analyze the mRNA relative expression. VAT PI3K expression had a lower level in obese compared to non-obese (P = 0.015), while its expression was higher in active individuals than inactive ones (P = 0.029). SAT PI3K expression was increased in active individuals compared to inactive ones (P = 0.031). There was a rise in VAT Akt expression in the actives compared to the inactive participants (P = 0.037) and in non-obese/active compared to non-obese/inactive individuals (P = 0.026). Obese individuals had a decreased expression level of SAT Akt compared to non-obsesses (P = 0.005). VAT PI3K was directly and significantly associated with PA in obsesses (β = 1.457, P = 0.015). Positive association between PI3K and PA suggests beneficial effects of PA for obese individuals that can be partly described by PI3K/Akt pathway acceleration in adipose tissue.

Adipocytokine plasma level changes in a 24-month dietary and physical activity randomised intervention trial in postmenopausal women

BACKGROUND

Adipocytokines are signaling molecules secreted by adipose tissue contributing to the control of body fat, energy expenditure and secretion of insulin and cytokines. They have been related to the development of obesity, type-2 diabetes, cardiovascular diseases and cancer. Diet and physical activity (PA) may have beneficial effects on their level. We evaluated the effects of a 24-month dietary and/or PA intervention on plasma levels of adipocytokines as a secondary analysis in the DAMA (Diet, physical Activity and Mammography) trial.

METHODS

The 234 study participants (healthy postmenopausal women with high breast density, 50-69 years, non-smokers, no hormone therapy) were randomised to four arms: (1) isocaloric dietary intervention mainly based on plant-foods; (2) moderate-intensity PA intervention with at least 1 h/week of supervised strenuous activity; (3) both interventions; (4) general recommendations on healthy dietary and PA patterns. Leptin, resistin and adiponectin were measured at baseline and at the end of the intervention. Analyses were performed using Tobit regression.

RESULTS

After 24 months, women randomised to PA intervention (arms #2 + #3) showed significant lower level of leptin (37.5% lower) and resistin (65.6% lower) compared to the control group (arms #1 + #4). No significant differences emerged in adiponectin levels. No significant differences in leptin, resistin and adiponectin levels at follow-up emerged in women randomised to the dietary intervention (arms #1 + #3) in comparison with controls (arms #2 + #4).

CONCLUSION

This study supports the effectiveness of PA, even at moderate intensity, in improving the leptin and resistin profile in postmenopausal women.

TRIAL REGISTRATION NUMBER

ISRCTN28492718, date of trial registration 17/05/2012.

The Influence of Conventional and Innovative Rehabilitation Methods on Brain Plasticity Induction in Patients with Multiple Sclerosis

Physical rehabilitation and physical activity are known non-pharmacological methods of treating multiple sclerosis. Both lead to an improvement in physical fitness in patients with movement deficits while improving cognitive function and coordination. These changes occur through the induction of brain plasticity. This review presents the basics of the induction of brain plasticity in response to physical rehabilitation. It also analyzes the latest literature evaluating the impact of traditional physical rehabilitation methods, as well as innovative virtual reality-based rehabilitation methods, on the induction of brain plasticity in patients with multiple sclerosis.

Physiological Role of Orexin/Hypocretin in the Human Body in Motivated Behavior: A Comprehensive Review

Neurohormones are neurosecretory materials released by neurosecretory cells that serve both as neuromodulators in the brain and spinal cord and as circulating regulatory hormones. They serve a wide range of functions, including homeostasis, development, and modulation of neuronal and muscle activity. In the hypothalamus, neurohormones called hypocretins are created that were discovered in the late nineties. Orexin receptors (OXRs) have been shown to enhance synaptic signaling in the central nervous system at the cellular level. The orexins improve stimulated neural activity in the hippocampus, which, in turn, aids with spatial memory, learning, and mood. They present themselves as mediators for the hypothalamic functions. They have been shown to regulate sleep-wake cycles, arousal mechanisms, addiction, sympathetic nerve activity (SNA), blood pressure, and thermogenesis. Its role in storing brown adipose tissue has implications for thermal homeostasis. The significant role of orexins is seen in tumorigenesis when orexin A (OrxA) and orexin B (OrxB) induce apoptosis in fast-growing tumor cells. Orexin-null subjects show clinical narcolepsy, indicating that orexins were responsible for keeping them awake. Orexin microinjections in mice brains stimulated increased physical activity, thus possibly countering diet-induced obesity. Physical activity significantly increased plasma orexin-A levels, which facilitated the process of energy homeostasis. The amount of adrenocorticotropic hormone (ACTH) increases in stress conditions, which further facilitates the release of the stress hormone cortisol. No increase in the ACTH hormone is seen in stressed mice administered with orexin receptor 2 (OX2R) antagonists thus showing orexin's role in stress reaction. As a result of linking hypocretin/orexin to various physiological procedures, increased research into the medicinal potential of drugs targeting these receptors is emerging. We summed up in this review the recent advances in our understanding of how orexin and its receptor system play an essential role in clinical and pathological functions. This research summarizes a new area for research in human medicine, providing the possibility of controlling a vast array of physiological functions through intra-cerebroventricular injections of a single neuropeptide.

Safety, tolerability, pharmacokinetic, and pharmacodynamic characteristics of vutiglabridin: A first-in-class, first-in-human study

This study aimed to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of vutiglabridin, a potential anti-obesity treatment under development, for the first time in humans. A randomized, placebo-controlled, single- and multiple-ascending dose study (SAD and MAD, respectively) was performed in healthy Koreans and Whites. Subjects randomly received a single oral dose of 30-720 mg vutiglabridin or placebo at a ratio of 8:2 in the SAD study or 240-480 mg vutiglabridin or placebo once daily for 14 days in the MAD study. Food effect was also evaluated in 240 mg single dose group. Pharmacokinetics were evaluated through plasma concentrations, and pharmacodynamic biomarkers related to obesity or inflammation were analyzed. Safety and tolerability were assessed throughout the study. Single and multiple doses of vutiglabridin were generally well-tolerated. The pharmacokinetic parameters show less than dose-proportionality increase, and plasma concentrations increased more than two-fold after multiple administrations. The mean half-life of Koreans and Whites in the MAD study was 110 and 73 h, respectively. The systemic exposure of vutiglabridin was significantly increased when taken with a high-fat meal, and the systemic exposure was lower in Whites than in Koreans. Vutiglabridin was well-tolerated in healthy Koreans and Whites. The plasma concentration increased less than the dose-proportionality manner. These results justify further investigation of vutiglabridin in patients with obesity.

Intermittent fasting and exercise therapy abates STZ-induced diabetotoxicity in rats through modulation of adipocytokines hormone, oxidative glucose metabolic, and glycolytic pathway

Diabetes is a global, costly, and growing public health issue. Intermittent fasting (IF) and exercise therapy have been shown to improve insulin sensitivity (IS) in large studies, although the underlying processes are still unknown. The goal of this study, which included both nondiabetic and diabetic rats, was to look at the mechanisms of intermittent fasting and exercise in the management of diabetotoxicity. The effects of starvation and honey on the oral glucose tolerance test, insulin tolerance test, adipocytokines, oxidative glucose metabolic enzymes, glycolytic enzymes, food intake, and body weight in rats with streptozotocin‐induced diabetes were also investigated. In the nondiabetic phase, rats were administered an oral regimen of distilled water (0.5 ml/rat), honey (1 g/kg body weight), and interventions with IF, and starvation for 4 weeks while in the diabetic phase, after STZ or citrate buffer injections, interventions with IF, exercise, starvation, and honey treatment began for 4 weeks. At all OGTT and ITT points, there was a substantial rise in glucose in the STZ group. Adipocytokines hormone, oxidative glucose metabolic enzymes, glycolytic enzymes, and body weight were all affected by STZ when compared to starvation and honey, however, IF and exercise significantly reduced these alterations. In diabetic rats, intermittent fasting and exercise enhanced serum adipocytokines levels. These findings imply that adipokines modulate glycolytic/nonmitochondrial enzymes and glucose metabolic/mitochondrial dehydrogenase to mediate the antidiabetic effects of intermittent fasting and exercise.

Intermittent fasting and exercise therapy abates STZ‐induced diabetotoxicity in rats through modulation of adipocytokines hormone, oxidative glucose metabolic, and glycolytic pathway.

Effects of aerobic exercise on adiponectin levels potentially mediated by vitamin D in type 2 diabetic patients

Objective. The positive effects of exercise on adiponectin and vitamin D have independently been reported. Recent studies have suggested that vitamin D increases adiponectin synthesis through inhibition of the rennin-angiotensin system in adipose tissue. However, studies evaluating the effects of an aerobic exercise on adiponectin and vitamin D simultaneously investigating the potential mechanism of vitamin D-dependent adiponectin pathways in patients with type 2 diabetes mellitus (T2DM) are still limited. This study was undertaken to examine the effects of aerobic exercise on adiponectin and its association with vitamin D in patients with T2DM.

Methods. Total twenty-two patients with T2DM were randomly divided into intervention and control group. The intervention group underwent a moderate intensity of a walking mode treadmill aerobic exercise for four weeks. The exercise protocol was adapted from modified Bruce test with a periodic speed and inclination increase. In both groups, body mass index (BMI), vitamin D, and adiponectin levels, were measured before and after four weeks of the lasting program.

Results. The mean of the increased adiponectin and vitamin D levels after exercise was significantly higher in the intervened than the control group, but statistically significant difference was only found in the adiponectin effect (p=0.017). There was a significant association found between vitamin D and adiponectin in the intervention group after data adjustments to age and BMI (p=0.005).

Conclusion. Moderate intensity of treadmill exercise with increased speed and inclination periodically increased adiponectin level in patients with T2DM. The increased adiponectin might potentially be mediated by increased vitamin D, but the level of their association impact was dependent on the age and BMI.

Exerkines and long-term synaptic potentiation: Mechanisms of exercise-induced neuroplasticity

Physical exercise may improve cognitive function by modulating molecular and cellular mechanisms within the brain. We propose that the facilitation of long-term synaptic potentiation (LTP)-related pathways, by products induced by physical exercise (i.e., exerkines), is a crucial aspect of the exercise-effect on the brain. This review summarizes synaptic pathways that are activated by exerkines and may potentiate LTP. For a total of 16 exerkines, we indicated how blood and brain exerkine levels are altered depending on the type of physical exercise (i.e., cardiovascular or resistance exercise) and how they respond to a single bout (i.e., acute exercise) or multiple bouts of physical exercise (i.e., chronic exercise). This information may be used for designing individualized physical exercise programs. Finally, this review may serve to direct future research towards fundamental gaps in our current knowledge regarding the biophysical interactions between muscle activity and the brain at both cellular and system levels.

Association of fasting Orexin-A levels with energy intake at breakfast and subsequent snack in Chilean adolescents

Orexin-A, a hormone secreted by orexin neurons, is involved in caloric-intake regulation. Current understanding is based primarily on animal studies. Studies of orexin in humans are scarce, and to our knowledge there are no prior studies in adolescents. We studied fasting Orexin-A levels related to energy intake at breakfast and a subsequent snack in adolescents (n = 668) from a longitudinal study in Chile. Body-Mass Index (BMI), components of the metabolic syndrome and fasting blood levels of leptin, insulin, ghrelin, and orexin-A were measured. Energy intake was calculated based on food weights before and after the standardized breakfast and subsequent snack. High energy intake was defined as ≥ 75th percentile. We assessed the relationship between orexin-A and high energy intake, adjusting for confounders. Higher orexin levels were associated with high breakfast energy intake (OR: 1.21; 95%CI: 0.98-1.49). Conversely, those with higher orexin levels showed a non-significant trend for lower odds of high energy intake for the snack (OR: 0.87; 95%CI: 0.70-1.07). There was a significant interaction between high breakfast energy intake and orexin levels. Those who ate more calories at breakfast displayed a lower inhibitory effect of orexin on eating at the snack (p < 0.05). There was no significant interaction between weight status and orexin. In conclusion, orexin-A levels were associated with breakfast energy intake and inversely related with subsequent snack energy intake in participants whose caloric intake at breakfast was within the normal range. Based on these findings, it appears that the association of orexin-A with energy intake depends on eating behavior.

Association of fasting orexin-A levels with energy intake at breakfast and subsequent snack in Chilean adolescents

Orexin-A, a hormone secreted by orexin neurons, is involved in caloric-intake regulation. Current understanding is based primarily on animal studies. Studies of orexin in humans are scarce, and to our knowledge there are no prior studies in adolescents. We studied fasting Orexin-A levels related to energy intake at breakfast and a subsequent snack in adolescents (n = 668) from a longitudinal study in Chile. Body-Mass Index (BMI), components of the metabolic syndrome and fasting blood levels of leptin, insulin, ghrelin, and orexin-A were measured. Energy intake was calculated based on food weights before and after the standardized breakfast and subsequent snack. High energy intake was defined as ≥ 75th percentile. We assessed the relationship between orexin-A and high energy intake, adjusting for confounders. Higher orexin levels were associated with high breakfast energy intake (OR: 1.21; 95%CI: 0.98-1.49). Conversely, those with higher orexin levels showed a non-significant trend for lower odds of high energy intake for the snack (OR: 0.87; 95%CI: 0.70-1.07). There was a significant interaction between high breakfast energy intake and orexin levels. Those who ate more calories at breakfast displayed a lower inhibitory effect of orexin on eating at the snack (p < 0.05). There was no significant interaction between weight status and orexin. In conclusion, orexin-A levels were associated with breakfast energy intake and inversely related with subsequent snack energy intake in participants whose caloric intake at breakfast was within the normal range. Based on these findings, it appears that the association of orexin-A with energy intake depends on eating behavior.

Orexin, serotonin, and energy balance

The lateral hypothalamus is critical for the control of ingestive behavior and spontaneous physical activity (SPA), as lesion or stimulation of this region alters these behaviors. Evidence points to lateral hypothalamic orexin neurons as modulators of feeding and SPA. These neurons affect a broad range of systems, and project to multiple brain regions such as the dorsal raphe nucleus, which contains serotoninergic neurons (DRN) important to energy homeostasis. Physical activity is comprised of intentional exercise and SPA. These are opposite ends of a continuum of physical activity intensity and structure. Non‐goal‐oriented behaviors, such as fidgeting, standing, and ambulating, constitute SPA in humans, and reflect a propensity for activity separate from intentional activity, such as high‐intensity voluntary exercise. In animals, SPA is activity not influenced by rewards such as food or a running wheel. Spontaneous physical activity in humans and animals burns calories and could theoretically be manipulated pharmacologically to expend calories and protect against obesity. The DRN neurons receive orexin inputs, and project heavily onto cortical and subcortical areas involved in movement, feeding and energy expenditure (EE). This review discusses the function of hypothalamic orexin in energy‐homeostasis, the interaction with DRN serotonin neurons, and the role of this orexin‐serotonin axis in regulating food intake, SPA, and EE. In addition, we discuss possible brain areas involved in orexin–serotonin cross‐talk; the role of serotonin receptors, transporters and uptake‐inhibitors in the pathogenesis and treatment of obesity; animal models of obesity with impaired serotonin‐function; single‐nucleotide polymorphisms in the serotonin system and obesity; and future directions in the orexin–serotonin field.

This article is categorized under:

Metabolic Diseases > Molecular and Cellular Physiology

Role of Vitamin E and the Orexin System in Neuroprotection

Microglia are the first line of defense at the level of the central nervous system (CNS). Phenotypic change in microglia can be regulated by various factors, including the orexin system. Neuroinflammation is an inflammatory process mediated by cytokines, by the lack of interaction between neurotransmitters and their specific receptors, caused by systemic tissue damage or, more often, associated with direct damage to the CNS. Chronic activation of microglia could lead to long-term neurodegenerative diseases. This review aims to explore how tocopherol (vitamin E) and the orexin system may play a role in the prevention and treatment of microglia inflammation and, consequently, in neurodegenerative diseases thanks to its antioxidant properties. The results of animal and in vitro studies provide evidence to support the use of tocopherol for a reduction in microglia inflammation as well as a greater activation of the orexinergic system. Although there is much in vivo and in vitro evidence of vitamin E antioxidant and protective abilities, there are still conflicting results for its use as a treatment for neurodegenerative diseases that speculate that vitamin E, under certain conditions or genetic predispositions, can be pro-oxidant and harmful.

Resistance training decreases plasma levels of adipokines in postmenopausal women

Physical inactivity and the onset of menopause increase the risk of cardiovascular disease amongst postmenopausal women. We aim to investigate the effect of resistance training (RT) on plasma levels of selected cytokines, adipokines, myokines, and sex hormones in postmenopausal women with vasomotor symptoms. This was a sub-study of a randomised controlled trial investigating the effects of RT on vasomotor symptoms in postmenopausal women. Women were randomised to join a 15-week RT program (n = 26) or remain sedentary as control (n = 29). Venous blood samples were taken at week-0 and week-15 for all participants. Enzyme-linked immunosorbent assays and multiple bead assays were used to measure cytokines, adipokines, myokines, and sex hormones in plasma. Plasma measurements of 16 of 33 analytes were within detectable limits. After adjusting for good compliance in the RT group (58% of RT participants), after 15 weeks, significantly lower plasma levels of adiponectin (p < 0.001), lipocalin-2 (p < 0.01) and resistin (p = 0.04) were found. Comparing control and RT women, using change-over-time values, significant increases in median testosterone and sex hormone binding globulin levels were seen in RT women. RT intervention lowers the levels of adipokines, particularly adiponectin, in postmenopausal women with vasomotor symptoms. These results were secondary outcomes of a clinical trial, and further investigations in a larger cohort are essential with the additional control of diet control and body composition analyses. Nevertheless, our study shows RT may be a beneficial intervention in reducing inflammation amongst postmenopausal women.

Unacylated Ghrelin Regulates Glucose-Sensitive Neurons Activity and Glycolipid Metabolism via Orexin-A Neurons in the Lateral Hypothalamic Area

The objective of the study was to investigate the regulatory actions of unacylated ghrelin (UAG) on glucose-sensitive (GS) neurons and glycolipid metabolism in the lateral hypothalamus area (LHA) and its involvement with orexin-A-immunopositive neurons. The effects of UAG administered into the LHA on GS neurons discharges and glycolipid metabolism were detected by single neuron discharge recording, biochemical index analysis and quantitative real-time PCR; the level of c-fos protein in orexin-A-immunopositive neurons was observed using immunofluorescence staining. UAG microinjected into the LHA activated glucose-inhibited neurons, which were partially blocked by pre-administration of anti-orexin-A antibody in the LHA. Furthermore, UAG microinjected into the LHA significantly reduced serum triglycerides (TG), total cholesterol, low-density lipoprotein cholesterol, blood glucose, insulin and hepatic TG levels, while elevated serum high-density lipoprotein cholesterol levels. UAG elevated the mRNA expression of carnitine palmitoyltransferase-1 and reduced the mRNA expression of acetyl-CoA carboxylase-1 in the liver. The above-mentioned effects of UAG were partially blocked by pre-administration of anti-orexin-A antibody. The expressions of orexin-A and c-fos were observed in the LHA. After UAG injection into the LHA, some neurons showed double labeling, and the percentage of double-labeled orexin-A/c-fos neurons in orexin-A-immunopositive neurons increased significantly. UAG in the LHA regulates glycolipid metabolism by activating orexin-A-immunopositive neurons in the LHA.