Glucagon-like peptide 1 interacts with ghrelin and leptin to regulate glucose metabolism and food intake through vagal afferent neuron signaling

Leptin and energy balance: exploring Leptin's role in the regulation of energy intake and energy expenditure

Leptin is a tonic appetite-regulating hormone, which is integral for the long-term regulation of energy balance. The current evidence suggests that the typical orexigenic or anorexigenic response of many of these appetite-regulating hormones, most notably ghrelin and cholecystokinin (CCK), require leptin to function whereas glucagon-like peptide-1 (GLP-1) is required for leptin to function, and these responses are altered when leptin injection or gene therapy is administered in combination with these same hormones or respective agonists. The appetite-regulatory pathway is complex, thus peptide tyrosine tyrosine (PYY), brain-derived neurotrophic factor (BDNF), orexin-A (OXA), and amylin also maintain ties to leptin, however these are less well understood. While reviews to date have focused on the existing relationships between leptin and the various neuropeptide modulators of appetite within the central nervous system (CNS) or it's role in thermogenesis, no review paper has synthesised the information regarding the interactions between appetite-regulating hormones and how leptin as a chronic regulator of energy balance can influence the acute appetite-regulatory response. Current evidence suggests that potential relationships exist between leptin and the circulating peripheral appetite hormones ghrelin, GLP-1, CCK, OXA and amylin to exhibit either synergistic or opposing effects on appetite inhibition. Though more research is warranted, leptin appears to be integral in both energy intake and energy expenditure. More specifically, functional leptin receptors appear to play an essential role in these processes.

High estradiol levels during a long agonist IVF protocol are associated with decreased food intake, higher leptin concentrations, and lower levels of high-sensitivity C-reactive protein

PURPOSE

To study whether different hormonal phases affect appetite regulation, food intake, and concentrations of leptin, glucagon-like peptide-1 (GLP-1), and high-sensitivity C-reactive protein (hs-CRP) during a long agonist in vitro fertilization (IVF) protocol.

METHODS

Fifty-four infertile women were encountered thrice, the first of which was at the beginning of their period (low estradiol). The other two visits were during a gonadotrophin-releasing hormone (GnRH) analog downregulation (low estradiol) and at the end of a follicle-stimulating hormone (FSH) stimulation (high estradiol). The first visit was the reference; the women served as their controls. The concentrations of leptin, GLP-1, and hs-CRP were assessed from plasma. Dietary intake was assessed using food records (FRs). In addition, weight, height, body mass index (BMI), and plasma levels of estradiol, glucose, HbA1c, insulin, and lipids were monitored. Twenty-six of the subjects also had a postprandial test.

RESULTS

During the stimulation protocol, leptin concentrations elevated (P < 0.001), and energy intake decreased (P = 0.03), while estradiol levels increased (P < 0.001). GLP-1 levels unchanged (P = 0.75) and hs-CRP (P = 0.03) concentrations diminished, while estradiol levels increased.

CONCLUSION

No increased food intake or weight gain occurred during the stimulation protocol; thus, leptin may protect from overeating during high estradiol levels, and leptin resistance may not occur during a short follow-up. Also, a favorable anti-inflammatory effect was detected. During this study, we observed no harmful metabolic effects, which might affect negatively maternal health.

Effects of the Inclusion of Dietary Bitter Gourd (Momordica charantia) on the Performance and Carcass Characteristics of Pigs: Potential Application in the Feed Chain

The objective of this study was to determine the effect of bitter gourd (BG) leftovers (stems and leaves) as an alternative dietary ingredient on pig performance, carcass characteristics, serum parameters (urea, insulin, and leptin levels), and faecal consistency. Healthy Tempo × Great Yorkshire and Landrace pigs (N = 240; 120 gilts and 120 boars) weighing 25.8 kg (9-10 weeks of age) were randomly assigned to three treatments (eight pens per treatment; each pen with five gilts and five boars). The three treatments consisted of a non-supplemented commercial diet (control; CON) and a CON diet supplemented with 6.5 g/kg BG (BG1) or 13 g/kg BG (BG2). Pigs were fed the experimental diets until slaughter (120 kg body weight; BW). Feed intake was recorded daily and calculated for each experimental phase (i.e., days 0-36, days 36-66, days 66-98, and the overall experimental period). Average daily feed intake (ADFI), average daily gain (ADG), and feed conversion ratio (FCR) were calculated. The frequencies of visiting the feed station and of feeding were recorded daily. Faecal scores (FS) for consistency were measured per pen twice weekly. On the day of slaughter, two pigs per pen (one male and one female) were randomly selected for the measurement of muscle thickness and blood collection. At the slaughterhouse, carcass weight, dressing percentage, back fat thickness, muscle depth, and lean meat percentage were recorded. Data were analysed using ANOVA, with the pen as the experimental unit. Diets BG1 or BG2 did not affect the performance of the pigs, except for a significant decrease in the ADG of the pigs fed the BG2 diet in the feeding period of 50-80 kg. However, no differences in performance were observed in the overall experimental period. Faecal scores, carcass quality, and serum levels of urea, insulin, and leptin were also not affected by the diet. In summary, leftovers (stems and leaves) of BG can be successfully added to the diet of growing-finishing pigs without interfering with performance and carcass characteristics.

Short-term effect of beinaglutide combined with metformin versus metformin alone on weight loss and metabolic profiles in obese patients with polycystic ovary syndrome: a pilot randomized trial

Objective

To observe the effect of beinaglutide combined with metformin versus metformin alone on weight loss and metabolic profiles in obese patients with polycystic ovary syndrome(PCOS).

Methods

A total of 64 overweight/obese women with PCOS diagnosed via the Rotterdam criteria were randomly assigned to metformin(MET) 850 mg twice a day(BID) or combined MET 850 mg BID with beinaglutide (COMB) starting at 0.1mg three times a day(TID)and increasing to 0.2mg TID two weeks later. The main endpoints were changes in anthropometric measurements of obesity. Glucose and lipid metabolic, gonadal profiles, and antral follicle count changes as secondary outcomes were also observed.

Results

60(93.75%) patients completed the study. In terms of lowering weight, body mass index (BMI),waist circumference(WC) and waist to height ratio(WHtR), COMB treatment outperformed MET monotherapy. Subjects in the COMB arm lost weight 4.54±3.16kg compared with a 2.47±3.59kg loss in the MET arm. In the COMB group, BMI,WC and WHtR were reduced significantly compared with that in the MET group, respectively. COMB therapy is also more favorable in the reduction of fasting insulin(FINS), total testosterone(TT), and homeostasis model assessment-insulin resistance(HOMA-IR) when compared to MET therapy. Antral follicle count and ovarian volume were non-significantly changed in both groups.The most frequent side effects in both groups were mild and moderate digestive symptoms. Itching and induration at the injection site were reported with COMB treatment.

Conclusion

Short-term combined treatment with beinaglutide and metformin appears superior to metformin monotherapy in lowering body weight, BMI, WC,WHtR and improving insulin sensitivity and androgen excess in women with PCOS and obesity, with tolerable adverse events.

Clinical trial registration

https://www.chictr.org.cn/listbycreater.aspx, identifier ChiCTR2000033741.

BI 456906: Discovery and preclinical pharmacology of a novel GCGR/GLP-1R dual agonist with robust anti-obesity efficacy

OBJECTIVE

Obesity and its associated comorbidities represent a global health challenge with a need for well-tolerated, effective, and mechanistically diverse pharmaceutical interventions. Oxyntomodulin is a gut peptide that activates the glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R) and reduces bodyweight by increasing energy expenditure and reducing energy intake in humans. Here we describe the pharmacological profile of the novel glucagon receptor (GCGR)/GLP-1 receptor (GLP-1R) dual agonist BI 456906.

METHODS

BI 456906 was characterized using cell-based in vitro assays to determine functional agonism. In vivo pharmacological studies were performed using acute and subchronic dosing regimens to demonstrate target engagement for the GCGR and GLP-1R, and weight lowering efficacy.

RESULTS

BI 456906 is a potent, acylated peptide containing a C18 fatty acid as a half-life extending principle to support once-weekly dosing in humans. Pharmacological doses of BI 456906 provided greater bodyweight reductions in mice compared with maximally effective doses of the GLP-1R agonist semaglutide. BI 456906's superior efficacy is the consequence of increased energy expenditure and reduced food intake. Engagement of both receptors in vivo was demonstrated via glucose tolerance, food intake, and gastric emptying tests for the GLP-1R, and liver nicotinamide N-methyltransferase mRNA expression and circulating biomarkers (amino acids, fibroblast growth factor-21) for the GCGR. The dual activity of BI 456906 at the GLP-1R and GCGR was supported using GLP-1R knockout and transgenic reporter mice, and an ex vivo bioactivity assay.

CONCLUSIONS

BI 456906 is a potent GCGR/GLP-1R dual agonist with robust anti-obesity efficacy achieved by increasing energy expenditure and decreasing food intake.

PROtein enriched MEDiterranean diet to combat undernutrition and promote healthy neuroCOGnitive ageing in older adults: The PROMED-COG consortium project

Dementia is a major public health challenge owing to its increasing prevalence and recognised impact on disability among older adults. Observational data indicate that weight loss is associated with increased dementia risk of 30%-40% and precedes a diagnosis of cognitive impairment or dementia by at least one decade. Although relatively little is known about the mechanisms of unintentional weight loss in dementia, this provides a window of opportunity to intervene with strategies to counteract undernutrition and delay, or prevent, the onset of dementia. This article provides an overview of the PROMED-COG project and associated work packages. The project aimes to (1) strengthen the epidemiologic evidence to better understand the potential benefits of combating undernutrition for healthy neurocognitive ageing; (2) increase scientific knowledge on the balance between a protein enriched Mediterranean diet (PROMED) and physical exercise to prevent undernutrition and promote healthy neurocognitive ageing, and generate data on mechanistic pathways; (3) stimulate collaboration and capacity building for nutrition and neurocognitive ageing research in Europe; and (4) develop public and practice recommendations to combat undernutrition and promote healthy neurocognitive ageing in older adults. Findings will provide new and critical insights into the role of undernutrition in neurocognitive ageing, how this role can differ by sex, genetic risk and timing of undernutrition exposure, and how modifications of dietary and physical activity behaviour can reduce the burden of undernutrition and neurodegeneration. The research outcomes will be useful to inform policy and practice about the dietary guidelines of older people and provide insight to industry for the development of food-based solutions to prevent undernutrition.

Gut microbes and food reward: From the gut to the brain

Inappropriate food intake behavior is one of the main drivers for fat mass development leading to obesity. Importantly the gut microbiota-mediated signals have emerged as key actors regulating food intake acting mainly on the hypothalamus, and thereby controlling hunger or satiety/satiation feelings. However, food intake is also controlled by the hedonic and reward systems leading to food intake based on pleasure (i.e., non-homeostatic control of food intake). This review focus on both the homeostatic and the non-homeostatic controls of food intake and the implication of the gut microbiota on the control of these systems. The gut-brain axis is involved in the communications between the gut microbes and the brain to modulate host food intake behaviors through systemic and nervous pathways. Therefore, here we describe several mediators of the gut-brain axis including gastrointestinal hormones, neurotransmitters, bioactive lipids as well as bacterial metabolites and compounds. The modulation of gut-brain axis by gut microbes is deeply addressed in the context of host food intake with a specific focus on hedonic feeding. Finally, we also discuss possible gut microbiota-based therapeutic approaches that could lead to potential clinical applications to restore food reward alterations. Therapeutic applications to tackle these dysregulations is of utmost importance since most of the available solutions to treat obesity present low success rate.

Short term effects of experimental gastric outlet obstruction and truncal vagotomy on gut hormones

Gastric outlet obstruction (GOO) is caused mainly by pyloric or duodenal blockage; gastric surgery and vagotomy are effective treatments. We investigated the short term effects of experimental GOO and truncal vagotomy (TV) on gut hormone levels. We used 8-week-old male Wistar rats divided randomly into four groups: control, GOO, TV, and GOO + TV. At the end of the experiment, blood and tissue samples of the pylorus and fundus were obtained for biochemical and immunohistochemical analysis. Gastric motility decreased in the TV group, but there was no difference in food intake compared to the control group; water consumption and urine output were increased. Feces excretion and food intake decreased due to loss of food movement from the stomach of GOO and GOO + TV rats. Levels of insulin and ghrelin were lower than for the control group, but levels of cholecystokinin were higher. Leptin and glucagon-like peptide 1 levels were increased in the GOO group, while somatostatin was decreased. Leptin immunostaining levels were decreased in the GOO + TV group. Gastrin and neuropeptide Y levels were lower in the GOO and GOO + TV groups compared to the other groups. We found that both gut hormone levels related to gastric motility and metabolism, and immunohistochemical staining of the stomach tissue were altered by TV and GOO. Measuring changes in gut hormones following gastric surgery could be useful for monitoring the effectiveness of treatment.

Vagal afferent cholecystokinin receptor activation is required for glucagon-like peptide-1-induced satiation

Peripheral glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) are secreted from enteroendocrine cells, and their plasma concentrations increase in response to eating. While the satiating effect of gut-derived CCK on food-intake control is well documented, the effect of peripheral GLP-1 is less clear. There is evidence that native GLP-1 can inhibit food intake only in the fed state but not in the fasting state. We therefore hypothesized that other gut peptides released during a meal might influence the subsequent effect of endogenous GLP-1 and investigated whether CCK could do so. We found that intraperitoneal injection of CCK in food-restricted mice inhibited food intake during the first 30-minute segment of a 1-hour session of ad libitum chow intake and that mice compensated by increasing their intake during the second half of the session. Importantly, this compensatory behaviour was abolished by an intraperitoneal injection of GLP-1 administered following an intraperitoneal injection of CCK and prior to the 1-hour session. In vivo activation of the free fatty acid 1 (FFA1) receptor with orally administered TAK875 increased plasma CCK concentration and, consistent with the effect of exogenous CCK, we found that prior oral administration of TAK875 increased the eating inhibitory effect of peripherally administered GLP-1. To examine the role of the vagus nerve in this effect, we utilized a saporin-based lesioning procedure to selectively ablate the CCK receptor-expressing gastrointestinal vagal afferent neurones (VANs). We found that the combined anorectic effect of TAK875 and GLP-1 was significantly attenuated in the absence of CCK receptor expressing VANs. Taken together, our results indicate that endogenous CCK interacts with GLP-1 to promote satiation and that activation of the FFA1 receptor can initiate this interaction by stimulating the release of CCK.

Effects of Chronic Intermittent Hypoxia and Chronic Sleep Fragmentation on Gut Microbiome, Serum Metabolome, Liver and Adipose Tissue Morphology

Chronic intermittent hypoxia (CIH) and chronic sleep fragmentation (CSF) are two cardinal pathological features of obstructive sleep apnea (OSA). Dietary obesity is a crucial risk intermediator for OSA and metabolic disorders. Gut microbiota affect hepatic and adipose tissue morphology under conditions of CIH or CSF through downstream metabolites. However, the exact relationship is unclear. Herein, chow and high-fat diet (HFD)-fed mice were subjected to CIH or CSF for 10 weeks each and compared to normoxia (NM) or normal sleep (NS) controls. 16S rRNA amplicon sequencing, untargeted liquid chromatography-tandem mass spectrometry, and histological assessment of liver and adipose tissues were used to investigate the correlations between the microbiome, metabolome, and lipid metabolism under CIH or CSF condition. Our results demonstrated that CIH and CSF regulate the abundance of intestinal microbes (such as Akkermansia mucinphila, Clostridium spp., Lactococcus spp., and Bifidobacterium spp.) and functional metabolites, such as tryptophan, free fatty acids, branched amino acids, and bile acids, which influence adipose tissue and hepatic lipid metabolism, and the level of lipid deposition in tissues and peripheral blood. In conclusion, CIH and CSF adversely affect fecal microbiota composition and function, and host metabolism; these findings provide new insight into the independent and synergistic effects of CIH, CSF, and HFD on lipid disorders.

Recombinant human GLP-1 beinaglutide regulates lipid metabolism of adipose tissues in diet-induced obese mice

GLP-1 analogs are a class of glucose-lowering agents with multiple benefits in diabetes, but its role in adipose tissues remains to be elucidated. The aim of this study was to determine the action of recombinant human GLP-1 (rhGLP-1) Beinaglutide (BN) in the insulin sensitivity and lipid metabolism of adipose tissues. We have shown that, after BN injection, obese mice displayed lower body weight, fat mass, and plasma lipid levels. In addition, BN promoted the insulin sensitivity in the white adipose tissues. Furthermore, we have found that the BN treatment caused significant changes in content and composition of different lipid classes, including glycerolipids, glycerophospholipids, and sphingolipids, as well as expression of genes in lipid metabolic pathways in the adipose tissues. Taken together, our data demonstrate that BN could resist HFD-induced obesity by targeting the composition of major lipid classes and the expression of genes in lipid metabolism of adipose tissues.

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Recombinant human GLP-1 Beinaglutide (BN) reduces high-fat-diet-induced obesity

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BN increases insulin sensitivity of adipocytes in vivo and in vitro

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BN alters lipidomic and transcriptomic profiles in adipose tissues of obese mice

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BN promotes thermogenic gene expression in adipose tissues

Learning of food preferences: mechanisms and implications for obesity & metabolic diseases

Omnivores, including rodents and humans, compose their diets from a wide variety of potential foods. Beyond the guidance of a few basic orosensory biases such as attraction to sweet and avoidance of bitter, they have limited innate dietary knowledge and must learn to prefer foods based on their flavors and postoral effects. This review focuses on postoral nutrient sensing and signaling as an essential part of the reward system that shapes preferences for the associated flavors of foods. We discuss the extensive array of sensors in the gastrointestinal system and the vagal pathways conveying information about ingested nutrients to the brain. Earlier studies of vagal contributions were limited by nonselective methods that could not easily distinguish the contributions of subsets of vagal afferents. Recent advances in technique have generated substantial new details on sugar- and fat-responsive signaling pathways. We explain methods for conditioning flavor preferences and their use in evaluating gut-brain communication. The SGLT1 intestinal sugar sensor is important in sugar conditioning; the critical sensors for fat are less certain, though GPR40 and 120 fatty acid sensors have been implicated. Ongoing work points to particular vagal pathways to brain reward areas. An implication for obesity treatment is that bariatric surgery may alter vagal function.

From leptin to lasers: the past and present of mouse models of obesity

Introduction: Obesity is a prevalent condition that accounts for significant morbidity and mortality across the globe. Despite substantial effort, most obesity pharmacotherapies have proven unsafe or ineffective. The use of obese mouse models provides unique insight into the hormones and mechanisms that regulate appetite and metabolism. Paramount among these models are the 'obese' and 'diabetic' mice that revealed the powerful satiety hormone leptin, revolutionizing obesity research.Areas Covered: In this article, the authors discuss work on leptin therapy, and the clinical response to leptin in humans. The authors describe the use of modern mouse genetics to study targetable mechanisms for genetic forms of human obesity. Additionally, they describe mouse models of neuromodulation and their utility in unraveling neural circuits that govern appetite and metabolism.Expert opinion: Combining past and present models of obesity is required for the development of safe, effective, and impactful obesity therapy. Current research in obesity can benefit from repositories of genetically engineered mouse models to discover interactions between appetitive systems and circuits. Combining leptin therapy with other satiety signals comprising the gut-brain axis is a promising approach to induce significant enduring weight loss.

The Links of Ghrelin to Incretins, Insulin, Glucagon, and Leptin After Bariatric Surgery

Type 2 diabetes mellitus (T2DM) is one of the most prominent and socially significant problems. The present study aimed to identify the mechanisms of interaction of critical regulators of carbohydrate metabolism using bioinformatics and experimental methods and to assess their influence on the development of T2DM. We conducted an in silico search for the relationship of hormones and adipokines and performed functional annotation of the receptors for ghrelin and incretins. Hormones and adipokines were assessed in the plasma of obese patients with and without T2DM as well as after laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB) surgeries. Incretin- and ghrelin-associated functions and metabolic processes were discovered. Low ghrelin levels were observed in obese patients without T2DM compared with healthy volunteers and the other groups. The highest ghrelin levels were observed in obese patients with T2DM. This defense mechanism against insulin resistance could be realized through the receptors G-protein-coupled receptor (GPCR), growth hormone secretagogue receptor (GHSR), and growth hormone-releasing hormone receptor (GHRHR). These receptors are associated with proliferative, inflammatory, and neurohumoral signaling pathways and regulate responses to nutrient intake. Signaling through the GPCR class unites ghrelin, glucagon, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide (GLP)-1. Ghrelin impairs carbohydrate and lipid metabolism in obese patients. Ghrelin is associated with elevated plasma levels of insulin, glucagon, and leptin. Specific activation of receptors and modulation by posttranslational modifications of ghrelin can control IR’s development in obesity, which is a promising area for research.

Transmission of Zearalenone, Deoxynivalenol, and Their Derivatives from Sows to Piglets during Lactation

Sows were fed naturally contaminated diets containing: (i) 100 ppb zearalenone (ZEN) one week before farrowing and during the lactation period (at 26 days), (ii) 100 ppb ZEN one week before farrowing and 300 ppb ZEN during the lactation period, or (iii) 300 ppb ZEN one week before farrowing and during the lactation period. All diets contained 250 ppb deoxynivalenol (DON). The highest levels of ZEN, α-ZEL, or β-ZEL were observed in the serum of sows fed 300 ppb ZEN before farrowing and during lactation. However, only α-ZEL was significantly increased in the colostrum and milk of these sows. Sows fed the 300 ppb ZEN during the complete trial presented a significant decrease in backfat thickness before farrowing. This effect was accompanied by a decrease in serum leptin levels. These sows also presented a decrease in estradiol levels and this effect was observed in their piglets exposed during lactation, which presented increased glucagon-like peptide 1, but no changes in serum levels of ZEN, α-ZEL, or β-ZEL. Although all sows were fed the same levels of DON, the serum levels of DON and de-epoxy-DON were increased only in the serum of piglets from the sows fed a diet with the highest ZEN levels during the whole experimental period. Moreover, these piglets presented gut inflammation, as indicated by significantly increased calprotectin levels in their serum.

Impact of Incretin-Based Therapies on Adipokines and Adiponectin

Adipokines are a family of hormones and cytokines with both pro- and anti-inflammatory effects released into the circulation to exert their hormonal effects. Adipokines are closely involved in most metabolic pathways and play an important modulatory role in lipid and carbohydrate homeostasis as they are involved in the pathophysiology of most metabolic disorders. Incretin-based therapy is a newly introduced class of antidiabetic drugs that restores euglycemia through several cellular processes; however, its effect on adipokines expression/secretion is not fully understood. In this review, we propose that incretin-based therapy may function through adipokine modulation that may result in pharmacologic properties beyond their direct antidiabetic effects, resulting in better management of diabetes and diabetes-related complications.

Immunity and the carotid body: implications for metabolic diseases

Neuro-immune communication has gained enormous interest in recent years due to increasing knowledge of the way in which the brain coordinates functional alterations in inflammatory and autoimmune responses, and the mechanisms of neuron-immune cell interactions in the context of metabolic diseases such as obesity and type 2 diabetes. In this review, we will explain how this relationship between the nervous and immune system impacts the pro- and anti-inflammatory pathways with specific reference to the hypothalamus-pituitary-adrenal gland axis and the vagal reflex and will explore the possible involvement of the carotid body (CB) in the neural control of inflammation. We will also highlight the mechanisms of vagal anti-inflammatory reflex control of immunity and metabolism, and the consequences of functional disarrangement of this reflex in settlement and development of metabolic diseases, with special attention to obesity and type 2 diabetes. Additionally, the role of CB in the interplay between metabolism and immune responses will be discussed, with specific reference to the different stimuli that promote CB activation and the balance between sympathetic and parasympathetic in this context. In doing so, we clarify the multivarious neuronal reflexes that coordinate tissue-specific responses (gut, pancreas, adipose tissue and liver) critical to metabolic control, and metabolic disease settlement and development. In the final section, we will summarize how electrical modulation of the carotid sinus nerve may be utilized to adjust these reflex responses and thus control inflammation and metabolic diseases, envisioning new therapeutics horizons.

Functional interaction between Ghrelin and GLP-1 regulates feeding through the vagal afferent system

The gastrointestinal tract transmits feeding-regulatory signals to the brain via neuronal and hormonal pathways. Here we studied the interaction between the orexigenic gastric peptide, ghrelin, and the anorectic intestinal peptide, glucagon-like peptide 1 (GLP-1), in terms of feeding regulation via the vagal afferents. GLP-1 preadministration 30 min before ghrelin administration to rats and mice abolished ghrelin-induced food intake, while ghrelin preadministration abolished the anorectic effect of GLP-1. Ghrelin preadministration suppressed GLP-1-induced Fos expression in the nodose ganglia (NG). Electrophysiological assessment confirmed that the initially administered peptide abolished the vagal afferent electrical alteration induced by the subsequently administered peptide. Both the growth hormone secretagogue receptor (GHSR) and the GLP-1 receptor (GLP-1R) are co-localised in a major proportion of NG neurons that innervate the stomach. In these Ghsr⁺Glp1r⁺ neurons, ghrelin preadministration abolished the GLP-1-induced calcium response. Ghrelin generated a hyperpolarising current and GLP-1 generated a depolarising current in isolated NG neurons in a patch-clamp experiment. Ghrelin and GLP-1 potently influenced each other in terms of vagally mediated feeding regulation. This peptidergic interaction allows for fine control of the electrophysiological properties of NG neurons.

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

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

Understanding Development of Malnutrition in Hemodialysis Patients: A Narrative Review

Hemodialysis (HD) majorly represents the global treatment option for patients with chronic kidney disease stage 5, and, despite advances in dialysis technology, these patients face a high risk of morbidity and mortality from malnutrition. We aimed to provide a novel view that malnutrition susceptibility in the global HD community is either or both of iatrogenic and of non-iatrogenic origins. This categorization of malnutrition origin clearly describes the role of each factor in contributing to malnutrition. Low dialysis adequacy resulting in uremia and metabolic acidosis and dialysis membranes and techniques, which incur greater amino-acid losses, are identified modifiable iatrogenic factors of malnutrition. Dietary inadequacy as per suboptimal energy and protein intakes due to poor appetite status, low diet quality, high diet monotony index, and/or psychosocial and financial barriers are modifiable non-iatrogenic factors implicated in malnutrition in these patients. These factors should be included in a comprehensive nutritional assessment for malnutrition risk. Leveraging the point of origin of malnutrition in dialysis patients is crucial for healthcare practitioners to enable personalized patient care, as well as determine country-specific malnutrition treatment strategies.

Evolution of Inflammatory and Oxidative Stress Markers in Romanian Obese Male Patients with Type 2 Diabetes Mellitus after Laparoscopic Sleeve Gastrectomy: One Year Follow-Up

Geography is one of the key drivers of the significant variation in the etiopathogenic profile and prevalence of type 2 diabetes mellitus (T2DM) and obesity, therefore geographically based data are fundamental for implementing the appropriate interventions. Presently, the selection criteria of T2DM and obesity patients for laparoscopic sleeve gastrectomy (LSG) have not reached a worldwide consensus—highlighting the need for sharing experts’ guidance in the preoperative evaluation, choice of the interventional procedure, perioperative management and patient long-term care. The aim of the current study was to evaluate the impact of LSG on T2DM (T2DM) remission in Romanian obese male patients, based on a multiparametric, prospective investigation. We have conducted a randomized controlled study on 41 obese male participants with the body mass index (BMI) ≥ 30 kg/m², aged 30–65 years, which were randomly divided in two study groups: one receiving conventional treatment and the second undergoing LSG. The clinical and anthropometrical parameters, resting metabolic rate, general biochemical status, adipocytes profile, gastrointestinal hormones levels, proinflammatory, oxidant and antioxidant profiles were determined at three time points: V1 (baseline), V2 (after six months) and V3 (after 12 months). Glycated hemoglobin (HbA1c), blood glucose levels, BMI, weight, visceral fat level, HDL-cholesterol, incretin hormones, proinflammatory and the oxidative stress status were significantly improved in the LSG versus conventional treatment group. This is the first study reporting on the evaluation of metabolic surgery impact on Romanian obese male patients with T2DM. Our results confirm that LSG could contribute to T2DM remission in patients with diabesity, but this beneficial effect seems to be critically influenced by the duration of T2DM rather than by the obesity status. Our results show that, in addition to the parameters included in the prediction algorithm, the proinsulin levels, proinsulin/insulin ratio and the visceral fat percentage could bring added value to the assessment of metabolic status.

Contribution of macronutrients to obesity: implications for precision nutrition

The specific metabolic contribution of consuming different energy-yielding macronutrients (namely, carbohydrates, protein and lipids) to obesity is a matter of active debate. In this Review, we summarize the current research concerning associations between the intake of different macronutrients and weight gain and adiposity. We discuss insights into possible differential mechanistic pathways where macronutrients might act on either appetite or adipogenesis to cause weight gain. We also explore the role of dietary macronutrient distribution on thermogenesis or energy expenditure for weight loss and maintenance. On the basis of the data discussed, we describe a novel way to manage excessive body weight; namely, prescribing personalized diets with different macronutrient compositions according to the individual's genotype and/or enterotype. In this context, the interplay of macronutrient consumption with obesity incidence involves mechanisms that affect appetite, thermogenesis and metabolism, and the outcomes of these mechanisms are altered by an individual's genotype and microbiota. Indeed, the interactions of the genetic make-up and/or microbiota features of a person with specific macronutrient intakes or dietary pattern consumption help to explain individualized responses to macronutrients and food patterns, which might represent key factors for comprehensive precision nutrition recommendations and personalized obesity management.

Anagliptin suppresses diet-induced obesity through enhancing leptin sensitivity and ameliorating hyperphagia in high-fat high-sucrose diet fed mice

Obesity is a major risk factors for type 2 diabetes, and weight loss is beneficial to diabetic patients who are obese or overweight. Dipeptidyl peptidase-4 (DPP-4) inhibitors are anti-diabetic drugs. Although it has been known that the effect of most of the DPP-4 inhibitors on body weight is neutral, several studies suggested that some DPP-4 inhibitors suppressed body weight. Nonetheless, the mechanisms underlying DPP-4 inhibitor-induced weight loss are not fully understood. In this study, the mice fed high-fat high sucrose diet (HFHSD) containing a DPP4 inhibitor, anagliptin, showed reduced food intake and body weight compared to the mice fed non-treated HFHSD, but oxygen consumption and respiratory exchange ratio (RER) were not altered. Sequential administration of leptin suppressed food intake and body weight more apparently in anagliptin treated HFHSD fed mice than non-treated HFHSD fed mice. Oxygen consumption and RER were comparable between anagliptin treated and non-treated mice after leptin administration. The number of phospho STAT3 expressed cells in the arcuate nucleus after leptin administration was increased in anagliptin treated mice compared to non-treated mice. These data suggested that anagliptin ameliorated leptin resistance induced by HFHSD and thereby decreased food intake and body weight. These effects of anagliptin could be beneficial to the treatment of obese diabetic patients.

The advantages and disadvantages of sleeve gastrectomy; clinical laboratory to bedside review

Sleeve gastrectomy is a surgical technique and a leading method in metabolic surgery. Sleeve gastrectomy gained ever-increasing popularity among laparoscopic surgeons involved in bariatric surgery and has proved to be a successful method in achieving considerable weight loss in a short time. There are some disparate effects that patients may experience after sleeve gastrectomy including a reduction in BMI, weight, blood pressure, stroke, and cancer and also a significant remission in obesity-related diseases including type 2 diabetes (T2D), Non-alcoholic fatty liver (NAFLD), cardiovascular disease, obstructive sleep apnea, and craniopharyngioma-related hypothalamic obesity as well as non-obesity-related diseases such as gout, musculoskeletal problems, ovarian disorders and urinary incontinence. The most common complications of sleeve gastrectomy are bleeding, nutrient deficiencies, and leakage. There are several studies on the impact of gender and ethnic disparities on post-operative complications. This study collects state of the art of reports on sleeve gastrectomy. The aim of this study was to analyze recent studies and review the advantages and disadvantages of sleeve gastrectomy.

Helicobacter pylori infection is associated with diabetes among Chinese adults

AIMS/INTRODUCTION

Several epidemiological studies investigated the effect of Helicobacter pylori infection on diabetes, but the conclusions remained inconsistent. We aimed to explore the relationship between H. pylori infection and diabetes, as well as glycemic metabolism profiles.

MATERIALS AND METHODS

A cross-sectional study including 58,482 Chinese adults was carried out between January 2016 and December 2017. H. pylori infection was diagnosed by the 13 C-urea breath test. Multivariate regression analyses were carried out to evaluate the association of H. pylori infection with diabetes.

RESULTS

Of the 58,482 participants, 3,449 (5.9%) had diabetes. The H. pylori-positive participants had a higher rate of diabetes (7.3% vs 5.2%, P < 0.001), and higher levels of fasting plasma glucose (5.36 ± 1.12 mmol/L vs 5.28 ± 0.95 mmol/L, P < 0.001) and glycated hemoglobin A1c (5.63 ± 0.68% vs 5.57 ± 0.60%, P < 0.001) than the H. pylori negative group. Multivariate regression analyses showed that H. pylori infection was positively related to diabetes (odds ratio 1.25, 95% confidence interval 1.15-1.35). Among the H. pylori-positive participants, the elevated levels of fasting plasma glucose and glycated hemoglobin A1c were 0.033 mmol/L (95% confidence interval 0.016-0.049 mmol/L) and 0.024% (95% confidence interval 0.008-0.041%), respectively. Additionally, H. pylori infection was significantly related to diabetes in participants aged ≥44 years, but not in participants aged <44 years.

CONCLUSIONS

The present study showed that H. pylori infection is associated with diabetes among Chinese adults. More attention should be paid to adults with H. pylori infection for effective prevention of diabetes.

Sustained release and pharmacologic evaluation of human glucagon-like peptide-1 and liraglutide from polymeric microparticles

The GLP1-receptor agonists exert regulatory key roles in diabetes, obesity and related complications. Here we aimed to develop polymeric microparticles loaded with homologous human GLP1 (7-37) or the analogue liraglutide. Peptide-loaded microparticles were prepared by a double emulsion and solvent evaporation process with a set of eight polymers based on lactide (PLA) or lactide-glycolide (PLGA), and evaluated for particle-size distribution, morphology, in vitro release and pharmacologic activity in mice. The resulting microparticles showed size distribution of about 30-50 μm. The in vitro kinetic release assays showed a sustained release of the peptides extending up to 30-40 days. In vivo evaluation in Swiss male mice revealed a similar extension of glycemic and body weight gain modulation for up to 25 days after a single subcutaneous administration of either hGLP1-microparticles or liraglutide-microparticles. Microparticles-loaded hGLP1 shows equivalent in vivo pharmacologic activity to the microparticles-loaded liraglutide.

The perceptions of natural compounds against dipeptidyl peptidase 4 in diabetes: from in silico to in vivo

Dipeptidyl peptidase IV (DPP-4), an incretin glucagon-like peptide-1 (GLP-1) degrading enzyme, contains two forms and it can exert various physiological functions particular in controlling blood glucose through the action of GLP-1. In diabetic use, the DPP-4 inhibitor can block the DDP-4 to attenuate GLP-1 degradation and prolong GLP-1 its action and sensitize insulin activity for the purpose of lowering blood glucose. Nonetheless the adverse effects of DPP-4 inhibitors severely hinder their clinical applications, and notably there is a clinical demand for novel DPP-4 inhibitors from various sources including chemical synthesis, herbs, and plants with fewer side effects. In this review, we highlight various strategies, namely computational biology (in silico), in vitro enzymatic and cell assays, and in vivo animal tests, for seeking natural DPP-4 inhibitors from botanic sources including herbs and plants. The pros and cons of all approaches for new inhibitor candidates or hits will be under discussion.

Inter-organ communication: a gatekeeper for metabolic health

Multidirectional interactions between metabolic organs in the periphery and the central nervous system have evolved concomitantly with multicellular organisms to maintain whole-body energy homeostasis and ensure the organism's adaptation to external cues. These interactions are altered in pathological conditions such as obesity and type 2 diabetes. Bioactive peptides and proteins, such as hormones and cytokines, produced by both peripheral organs and the central nervous system, are key messengers in this inter-organ communication. Despite the early discovery of the first hormones more than 100 years ago, recent studies taking advantage of novel technologies have shed light on the multiple ways used by cells in the body to communicate and maintain energy balance. This review briefly summarizes well-established concepts and focuses on recent advances describing how specific proteins and peptides mediate the crosstalk between gut, brain, and other peripheral metabolic organs in order to maintain energy homeostasis. Additionally, this review outlines how the improved knowledge about these inter-organ networks is helping us to redefine therapeutic strategies in an effort to promote healthy living and fight metabolic disorders and other diseases.

Relationships between Body Composition and Plasma Levels of Pancreatic, Gut, and Adipose Tissue Hormones in db/db Mice, a Model of Type 2 Diabetes Mellitus

We studied the relationships between body composition parameters and plasma levels of pancreatic, gut, and adipose tissue hormones regulating energy balance and glucose metabolism in diabetic db/db mice (BKS.Cg-Dock7^m+/+Lepr^db/J). The body composition parameters in mice aged 8, 12, and 16 weeks were assessed by magnetic resonance imaging. The concentrations of insulin, glucagon, ghrelin, glucagon-like peptide-1, glucose-dependent immunotropic peptide, leptin, resistin, and plasminogen activator-1 were measured by multiplex analysis at the age of 8 and 16 weeks. In comparison with non-diabetic control (db/+), db/db mice demonstrated high fat mass and reduced lean body mass and water content. In 8- and 16-week-old db/db mice, the levels of leptin (p<0.001), insulin (p<0.01), and glucagon-like peptide-1 (p<0.05) were elevated and the concentration of ghrelin (p<0.05) was reduced. The body weight and fat mass positively correlated with the levels of leptin, insulin, plasminogen activator-1, and glucagon-like peptide-1 and negatively correlated with ghrelin concentration. The results provide further details for characteristics of db/db mice, a widely used model of obesity and type 2 diabetes mellitus.

Glucagon, GLP-1 and Thermogenesis

Brown adipose tissue (BAT) thermogenesis is a conserved mechanism to maintain body temperature in mammals. However, since BAT contribution to energy expenditure can represent a relevant modulator of metabolic homeostasis, many studies have focused on the nervous system and endocrine factors that control the activity of this tissue. There is long-established evidence that the counter-regulatory hormone glucagon negatively influences energy balance, enhances satiety, and increases energy expenditure. Despite compelling evidence showing that glucagon has direct action on BAT thermogenesis, recent findings are questioning this conventional attribute of glucagon action. Glucagon like peptide-1 (GLP-1) is an incretin secreted by the intestinal tract which strongly decreases feeding, and, furthermore, improves metabolic parameters associated with obesity and diabetes. Therefore, GLP-1 receptors (GLP-1-R) have emerged as a promising target in the treatment of metabolic disorders. In this short review, we will summarize the latest evidence in this regard, as well as the current therapeutic glucagon- and GLP-1-based approaches to treating obesity.

From Normal to Obesity and Back: The Associations between Mitochondrial DNA Copy Number, Gender, and Body Mass Index

Mitochondrial DNA (mtDNA) encodes core subunits of oxidative phosphorylation complexes and, as a result of intricate regulatory crosstalk between nuclear and mitochondrial genomes, the total number of mtDNA copies fits the requirements of each cell type. Deviations from the physiological number of mtDNA copies are expected to be deleterious and might cause some inherited diseases and normal ageing. We studied 46 obese patients with type 2 diabetes (T2DM) one year after a laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB). The results were compared with normal-weight patients without T2DM (control group 1) (body mass index (BMI) = 22.5 ± 3.01 kg/m²) and patients with obesity without T2DM (control group 2) (BMI = 36 ± 3.45 kg/m²). We detected an increase of mtDNA copy number in the cells of the buffy coat obtained from peripheral blood, sampled one year after bariatric surgery. We also found that average mtDNA copy number as well as its dynamics (before and after the surgery) are gender-specific. To the best of our knowledge, this is the first evidence for the restoration of mtDNA copy number in obese patients after LSG and RYGB.

Vagal Interoceptive Modulation of Motivated Behavior

In addition to regulating the ingestion and digestion of food, sensory feedback from gut to brain modifies emotional state and motivated behavior by subconsciously shaping cognitive and affective responses to events that bias behavioral choice. This focused review highlights evidence that gut-derived signals impact motivated behavior by engaging vagal afferents and central neural circuits that generally serve to limit or terminate goal-directed approach behaviors, and to initiate or maintain behavioral avoidance.

Microbial regulation of organismal energy homeostasis

The gut microbiome has emerged as a key regulator of host metabolism. Here we review the various mechanisms through which the gut microbiome influences the energy metabolism of its host, highlighting the complex interactions between gut microbes, their metabolites and host cells. Among the most important bacterial metabolites are short-chain fatty acids, which serve as a direct energy source for host cells, stimulate the production of gut hormones and act in the brain to regulate food intake. Other microbial metabolites affect systemic energy expenditure by influencing thermogenesis and adipose tissue browning. Both direct and indirect mechanisms of action are known for specific metabolites, such as bile acids, branched chain amino acids, indole propionic acid and endocannabinoids. We also discuss the roles of specific bacteria in the production of specific metabolites and explore how external factors, such as antibiotics and exercise, affect the microbiome and thereby energy homeostasis. Collectively, we present a large body of evidence supporting the concept that gut microbiota-based therapies can be used to modulate host metabolism, and we expect to see such approaches moving from bench to bedside in the near future.

Farnesoid X receptor interacts with cAMP response element binding protein to modulate glucagon-like peptide-1 (7-36) amide secretion by intestinal L cell

Type II diabetes is a complex, chronic, and progressive disease. Glucagon-like peptide-1 (7-36) amide (GLP-1) is a gut hormone released from the L cells which stimulate insulin secretion and promotes insulin gene expression and β-cell growth and differentiation. Elevated levels of hormones secreted by L cells are an essential reason for diabetes improvement. GLP-1 secretion has been reported to be regulated by farnesoid X receptor (FXR), a transcriptional sensor for bile acids which also acts on glucose metabolism. Herein, we attempted to evaluate the effect of FXR on GLP-1 secretion in mouse enteroendocrine L cell line, namely STC-1, and to investigate the underlying mechanism. FXR inversely regulated GLP-1 secretion in STC-1. A total of 24 nonredundant human proteins were shown to be related to FXR by BioGRID; KEGG pathway analysis revealed that FXR was related to glucagon signaling pathway, particularly with the transcriptional activators CREB, PGC1α, Sirt1, and CBP. CREB could positively regulate GLP-1 secretion in STC-1 cells. FXR combined with CREB to inhibit its transcriptional activity, thus inhibiting proprotein convertase subtilisin/kexin type 1 protein level and GLP-1 secretion. In the present study, we demonstrated a negative regulation of GLP-1 secretion by FXR in L cell line, STC-1; FXR exerts its function in L cells through interacting with CREB, a crucial transcriptional regulator of cAMP-CREB signaling pathway, to inhibit its transcriptional activity. Targeting FXR to rescue GLP-1 secretion may be a promising strategy for type II diabetes.

The metabolic role of vagal afferent innervation

The regulation of energy and glucose balance contributes to whole-body metabolic homeostasis, and such metabolic regulation is disrupted in obesity and diabetes. Metabolic homeostasis is orchestrated partly in response to nutrient and vagal-dependent gut-initiated functions. Specifically, the sensory and motor fibres of the vagus nerve transmit intestinal signals to the central nervous system and exert biological and physiological responses. In the past decade, the understanding of the regulation of vagal afferent signals and of the associated metabolic effect on whole-body energy and glucose balance has progressed. This Review highlights the contributions made to the understanding of the vagal afferent system and examines the integrative role of the vagal afferent in gastrointestinal regulation of appetite and glucose homeostasis. Investigating the integrative and metabolic role of vagal afferent signalling represents a potential strategy to discover novel therapeutic targets to restore energy and glucose balance in diabetes and obesity.

Antibiotic-induced microbiome depletion alters metabolic homeostasis by affecting gut signaling and colonic metabolism

Antibiotic-induced microbiome depletion (AIMD) has been used frequently to study the role of the gut microbiome in pathological conditions. However, unlike germ-free mice, the effects of AIMD on host metabolism remain incompletely understood. Here we show the effects of AIMD to elucidate its effects on gut homeostasis, luminal signaling, and metabolism. We demonstrate that AIMD, which decreases luminal Firmicutes and Bacteroidetes species, decreases baseline serum glucose levels, reduces glucose surge in a tolerance test, and improves insulin sensitivity without altering adiposity. These changes occur in the setting of decreased luminal short-chain fatty acids (SCFAs), especially butyrate, and the secondary bile acid pool, which affects whole-body bile acid metabolism. In mice, AIMD alters cecal gene expression and gut glucagon-like peptide 1 signaling. Extensive tissue remodeling and decreased availability of SCFAs shift colonocyte metabolism toward glucose utilization. We suggest that AIMD alters glucose homeostasis by potentially shifting colonocyte energy utilization from SCFAs to glucose.

Antibiotic-induced microbiome depletion is one of the most common approaches to modulate the gut microbiome. Here the authors demonstrate that it affects gut homeostasis and glucose metabolism by decreasing luminal short chain fatty acids and leading to a shift of energy utilization by colonocytes.

Dual Therapy with Liraglutide and Ghrelin Promotes Brain and Peripheral Energy Metabolism in the R6/2 Mouse Model of Huntington's Disease

Neuronal loss alongside altered energy metabolism, are key features of Huntington’s disease (HD) pathology. The orexigenic gut-peptide hormone ghrelin is known to stimulate appetite and affect whole body energy metabolism. Liraglutide is an efficient anti-type 2 diabetes incretin drug, with neuroprotective effects alongside anorectic properties. Combining liraglutide with the orexigenic peptide ghrelin may potentially promote brain/cognitive function in HD. The R6/2 mouse model of HD exhibits progressive central pathology, weight loss, deranged glucose metabolism, skeletal muscle atrophy and altered body composition. In this study, we targeted energy metabolism in R6/2 mice using a co-administration of liraglutide and ghrelin. We investigated their effect on brain cortical hormone-mediated intracellular signalling pathways, metabolic and apoptotic markers, and the impact on motor function in HD. We here demonstrate that liraglutide, alone or together with ghrelin (subcutaneous daily injections of 150 µg/kg (ghrelin) and 0.2 mg/kg (liraglutide), for 2 weeks), normalized glucose homeostatic features in the R6/2 mouse, without substantially affecting body weight or body composition. Liraglutide alone decreased brain cortical active GLP-1 and IGF-1 levels in R6/2 mice, alongside higher ADP levels. Liraglutide plus ghrelin decreased brain insulin, lactate, AMP and cholesterol levels in R6/2 mice. Taken together, our findings encourage further studies targeting energy metabolism in HD.

Profiling of G protein-coupled receptors in vagal afferents reveals novel gut-to-brain sensing mechanisms

OBJECTIVES

G protein-coupled receptors (GPCRs) act as transmembrane molecular sensors of neurotransmitters, hormones, nutrients, and metabolites. Because unmyelinated vagal afferents richly innervate the gastrointestinal mucosa, gut-derived molecules may directly modulate the activity of vagal afferents through GPCRs. However, the types of GPCRs expressed in vagal afferents are largely unknown. Here, we determined the expression profile of all GPCRs expressed in vagal afferents of the mouse, with a special emphasis on those innervating the gastrointestinal tract.

METHODS

Using a combination of high-throughput quantitative PCR, RNA sequencing, and in situ hybridization, we systematically quantified GPCRs expressed in vagal unmyelinated Nav1.8-expressing afferents.

RESULTS

GPCRs for gut hormones that were the most enriched in Nav1.8-expressing vagal unmyelinated afferents included NTSR1, NPY2R, CCK1R, and to a lesser extent, GLP1R, but not GHSR and GIPR. Interestingly, both GLP1R and NPY2R were coexpressed with CCK1R. In contrast, NTSR1 was coexpressed with GPR65, a marker preferentially enriched in intestinal mucosal afferents. Only few microbiome-derived metabolite sensors such as GPR35 and, to a lesser extent, GPR119 and CaSR were identified in the Nav1.8-expressing vagal afferents. GPCRs involved in lipid sensing and inflammation (e.g. CB1R, CYSLTR2, PTGER4), and neurotransmitters signaling (CHRM4, DRD2, CRHR2) were also highly enriched in Nav1.8-expressing neurons. Finally, we identified 21 orphan GPCRs with unknown functions in vagal afferents.

CONCLUSION

Overall, this study provides a comprehensive description of GPCR-dependent sensing mechanisms in vagal afferents, including novel coexpression patterns, and conceivably coaction of key receptors for gut-derived molecules involved in gut-brain communication.

Exercise, Obesity and CNS Control of Metabolic Homeostasis: A Review

This review details the manner in which the central nervous system regulates metabolic homeostasis in normal weight and obese rodents and humans. It includes a review of the homeostatic contributions of neurons located in the hypothalamus, the midbrain and limbic structures, the pons and the medullary area postrema, nucleus tractus solitarius, and vagus nucleus, and details how these brain regions respond to circulating levels of orexigenic hormones, such as ghrelin, and anorexigenic hormones, such as glucagon-like peptide 1 and leptin. It provides an insight as to how high intensity exercise may improve homeostatic control in overweight and obese subjects. Finally, it provides suggestions as to how further progress can be made in controlling the current pandemic of obesity and diabetes.

Aripiprazole-induced adverse metabolic alterations in polyI:C neurodevelopmental model of schizophrenia in rats

Schizophrenia appears to be linked to higher incidence of metabolic syndrome even in the absence of antipsychotic treatment. Atypical antipsychotics substantially differ in their propensity to induce metabolic alterations. Aripiprazole is considered to represent an antipsychotic drug with low risk of metabolic syndrome development. The aim of this study was to evaluate metabolic phenotype of neurodevelopmental polyI:C rat model and assess metabolic effects of chronic aripiprazole treatment with regard to complex neuroendocrine regulations of energy homeostasis. Polyinosinic:polycytidylic acid (polyI:C) was administered subcutaneously at a dose of 8 mg/kg in 10 ml on gestational day 15 to female Wistar rats. For this study 20 polyI:C and 20 control adult male offspring were used, randomly divided into 2 groups per 10 animals for chronic aripiprazole treatment and vehicle. Aripiprazole (5 mg/kg, dissolved tablets, ABILIFY^®) was administered once daily via oral gavage for a month. Altered lipid profile in polyI:C model was observed and a trend towards different dynamics of weight gain in polyI:C rats was noted in the absence of significant antipsychotic treatment effect. PolyI:C model was not associated with changes in other parameters i.e. adipokines, gastrointestinal hormones and cytokines levels. Aripiprazole did not influence body weight but it induced alterations in neurohumoral regulations. Leptin and GLP-1 serum levels were significantly reduced, while ghrelin level was elevated. Furthermore aripiprazole decreased serum levels of pro-inflammatory cytokines. Our data indicate dysregulation of adipokines and gastrointestinal hormones present after chronic treatment with aripiprazole which is considered metabolically neutral in the polyI:C model of schizophrenia.

Characteristics of eating behavior and the level of hormones regulating the appetite in patients with type 2 diabetes mellitus and body mass index more than 35 kg /m2

Background. The role of the hormones in eating behavior in the regulation of appetite has been well studied, but their relationship with various types of eating behavior has not been established. Aims. To study the frequency of different types of eating behavior, hunger/satiety feeling estimated by the visual analog scale and levels of leptin and gastrointestinal tract hormones that are involved in appetite regulation, fat and carbohydrate metabolism (ghrelin and glucagon-like peptide 1) in patients with diabetes mellitus type 2 and obesity. Materials and methods. The study included 35 people with obesity (BMI35 kg/m2) and diabetes mellitus type 2 (T2DM) who received the stable sugar-lowering therapy, the median body mass index (BMI) was 40,1 [36,5; 49,6] kg/m2, the median age was 58 [52,5; 64] years. Blood tests for insulin, leptin, ghrelin, glucagon-like peptide-1, C-peptide, glucose, glycated hemoglobin and lipids profile were done in all cases, also HOMA-IR and HOMA- were calculated. All patients completed questionnaires determining eating behavior type and hunger/satiety feeling severity. Results. In patients with T2DM and obesity a high frequency of combination of different types of eating behavior were found, it was 54,3%. Among the isolated types, restrictive eating behavior was more common in 40%. In patients with different types of eating behavior the tendency to difference in the level of hormones regulating appetite was found, but it was not significant. High frequency of an appropriate reduction of postprandial ghrelin level was found in patients with restrictive type of eating behavior. Correlation between the level of hormones regulating appetite and hunger/satiety feeling was weak, it might reflect the resistance to these hormones in patients with severe obesity and T2DM. At the same time the relationship between the ghrelin level and the -cells functional state parameters was significant. Conclusions. The severity of leptin and ghrelin resistance correlated with each other in T2DM and obesity patients; the severity of ghrelin resistance was associated with the beta cells functional state; according to our data postprandial ghrelin level may have opposite changes in patients with T2DM and obesity and its adequate reduction is more common for patients with restrictive type of eating behavior.

Semaglutide improves postprandial glucose and lipid metabolism, and delays first-hour gastric emptying in subjects with obesity

AIM

To investigate the effects of semaglutide on fasting and postprandial glucose and lipid responses, and on gastric emptying.

MATERIALS AND METHODS

This was a randomized, double-blind, placebo-controlled, 2-period, crossover trial. Subjects with obesity (N = 30) received once-weekly subcutaneous semaglutide, dose-escalated to 1.0 mg, or placebo. After each 12-week treatment period, glucose and lipid metabolism were assessed before and after standardized meals. Gastric emptying (paracetamol absorption test) and peptide YY (PYY) response were also assessed.

RESULTS

Semaglutide treatment significantly lowered fasting concentrations of glucose and glucagon, and increased insulin vs placebo (estimated treatment ratio: 0.95 [95% confidence interval: 0.91, 0.98]; 0.86 [0.75, 0.98]; 1.45 [1.20, 1.75], respectively). Postprandial glucose metabolism significantly improved with semaglutide vs placebo (incremental area under the curve 0 to 5 hours [iAUC0-5h ]; estimated treatment difference: glucose -1.34 mmol h/L [-2.42, -0.27]; insulin -921 pmol h/L [-1461, -381]; C-peptide -1.42 nmol h/L [-2.33, -0.51]). Fasting and postprandial lipid metabolism improved with semaglutide vs placebo. First-hour gastric emptying after the meal was delayed with semaglutide vs placebo (AUC0-1h ; estimated treatment ratio: 0.73 [0.61, 0.87]); this may have contributed to the lower postprandial glucose increase in semaglutide-treated subjects. Overall gastric emptying (AUC0-5h ) was not statistically different between treatments. Fasting and postprandial PYY responses were significantly lower with semaglutide vs placebo (P = .0397 and P = .0097, respectively).

CONCLUSION

Semaglutide improved fasting and postprandial glucose and lipid metabolism. Overall gastric emptying was similar to that with placebo; however, the observed first-hour delay with semaglutide may contribute to a slower entry of glucose into the circulation.

The Anorexigenic Neural Pathways of Oxytocin and Their Clinical Implication

Oxytocin was discovered in 1906 as a peptide that promotes delivery and milk ejection; however, its additional physiological functions were determined 100 years later. Many recent articles have reported newly discovered effects of oxytocin on social communication, bonding, reward-related behavior, adipose tissue, and muscle and food intake regulation. Because oxytocin neurons project to various regions in the brain that contribute to both feeding reward (hedonic feeding) and the regulation of energy balance (homeostatic feeding), the mechanisms of oxytocin on food intake regulation are complicated and largely unknown. Oxytocin neurons in the paraventricular nucleus (PVN) receive neural projections from the arcuate nucleus (ARC), which is an important center for feeding regulation. On the other hand, these neurons in the PVN and supraoptic nucleus project to the ARC. PVN oxytocin neurons also project to the brain stem and the reward-related limbic system. In addition to this, oxytocin induces lipolysis and decreases fat mass. However, these effects in feeding and adipose tissue are known to be dependent on body weight (BW). Oxytocin treatment is more effective in food intake regulation and fat mass decline for individuals with leptin resistance and higher BW, but is known to be less effective in individuals with normal BW. In this review, we present in detail the recent findings on the physiological role of oxytocin in feeding regulation and the anorexigenic neural pathway of oxytocin neurons, as well as the advantage of oxytocin usage for anti-obesity treatment.