The role of gut hormones in appetite regulation (review)

PACAP and VIP Neuropeptides' and Receptors' Effects on Appetite, Satiety and Metabolism

The overwhelming increase in the prevalence of obesity and related disorders in recent years is one of the greatest threats to the global healthcare system since it generates immense healthcare costs. As the prevalence of obesity approaches epidemic proportions, the importance of elucidating the mechanisms regulating appetite, satiety, body metabolism, energy balance and adiposity has garnered significant attention. Currently, gastrointestinal (GI) bariatric surgery remains the only approach capable of achieving successful weight loss. Appetite, satiety, feeding behavior, energy intake and expenditure are regulated by central and peripheral neurohormonal mechanisms that have not been fully elucidated yet. Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) and Vasoactive Intestinal Polypeptide (VIP) are members of a family of regulatory peptides that are widely distributed in parallel with their specific receptors, VPAC1R, VPAC2R and PAC1R, in the central nervous system (CNS) and in the periphery, such as in the gastrointestinal tract and its associated organs and immune cells. PACAP and VIP have been reported to play an important role in the regulation of body phenotype, metabolism and homeostatic functions. The purpose of this review is to present recent data on the effects of PACAP, VIP, VPAC1R, VPAC2R and PAC1R on the modulation of appetite, satiety, metabolism, calorie intake and fat accumulation, to evaluate their potential use as therapeutic targets for the treatment of obesity and metabolic syndrome.

Association of ghrelin gene polymorphisms with slaughter traits in pig

It has been hypothesized that mutations in the ghrelin gene in pigs may play a similar role as in humans and may be associated with obesity. The aim of study was to analyse the polymorphisms of ghrelin gene and to evaluate its effect on pigs’ carcass traits. The effect of c.-93A>G, 4428T>C and g.4486C>T polymorphisms at the ghrelin gene on slaughter performance were analysed in 346 gilts represented by three breeds (Polish Landrace, Duroc, Pietrain). Animals were fattened from 30 to 100 (±2.5) kg body weight. After slaughter, the carcasses were chilled for 24 hours (4ºC), weighted and the right half-carcasses were dissected and evaluated. A number of data were obtained including: meat weight in primary cuts, weight of ham, backfat thickness and carcass yield. From breeding and production point of view, the favourable results were obtained for pigs with the GG genotype at the c.-93A>G locus, characterized by better carcass results than those with the AA genotype, e.g. higher ham weight and lower average backfat thickness. In pigs with the TT genotype at the g.4428T>C locus, we found lower mean backfat thickness than pigs with the CC genotype.

Suprachiasmatic to paraventricular nuclei interaction generates normal food searching rhythms in mice

Searching for food follows a well-organized decision process in mammals to take up food only if necessary. Moreover, scavenging is preferred during their activity phase. Various time-dependent regulatory processes have been identified originating from the suprachiasmatic nuclei (SCN), which convert external light information into synchronizing output signals. However, a direct impact of the SCN on the timing of normal food searching has not yet been found. Here, we revisited the function of the SCN to affect when mice look for food. We found that this process was independent of light but modified by the palatability of the food source. Surprisingly, reducing the output from the SCN, in particular from the vasopressin releasing neurons, reduced the amount of scavenging during the early activity phase. The SCN appeared to transmit a signal to the paraventricular nuclei (PVN) via GABA receptor A1. Finally, the interaction of SCN and PVN was verified by retrograde transport-mediated complementation. None of the genetic manipulations affected the uptake of more palatable food. The data indicate that the PVN are sufficient to produce blunted food searching rhythms and are responsive to hedonistic feeding. Nevertheless, the search for normal food during the early activity phase is significantly enhanced by the SCN.

The significance and potential of functional food ingredients for control appetite and food intake

Dramatically rising global levels of obesity have raised consumers’ commercial and public health interest in foods that may help control appetite and weight. The satiety cascade consists of sensory, cognitive, physical, and hormonal events following food intake, preventing overeating, and the desire to eat for a long time. Functional foods can be one of the most influential factors in reducing appetite as long as effective ingredients, such as fiber and protein, are used to design these products. Also, functional foods should be designed to reduce appetite at different levels of oral processing, stomach, small intestine, and large intestine by various mechanisms. Therefore, the satiety power of functional foods depends on the type of ingredients and their amount. Because each compound has a different mechanism of action, it is recommended to use different compounds to influence satiety in functional foods.

The VIP/VPAC1R Pathway Regulates Energy and Glucose Homeostasis by Modulating GLP-1, Glucagon, Leptin and PYY Levels in Mice

Simple Summary

The current study is the first complete characterization of the phenotypic, metabolic, calorimetric, and homeostatic effects of VPAC1R in a null murine model. To evaluate the role of VPAC1R on body phenotype, feeding behavior, glucose/energy homeostasis, metabolic rate and plasma hormones, a long-term study was conducted in VPAC1R^−/− and WT mice. The outcome data document that VPAC1R^−/− mice have altered metabolism and insulin intolerance, with significant increase of feeding bouts, reduction of total energy expenditure and respiratory gases during both the dark and light cycle, together with elevated fasting levels of GLP-1 and PYY, and higher postprandial levels of GLP-1, glucagon leptin and PYY. These findings suggests that VPAC1R controls glucose homeostasis and energy balance by regulating plasma metabolic hormones.

Abstract

Vasoactive Intestinal Peptide binds with high affinity to VPAC1R and VPAC2R, thus regulating key physiologic functions. Previously, we documented in VIP^−/− mice a leaner body phenotype and altered metabolic hormones. Past reports described in VPAC2^−/− mice impaired circadian rhythm, reduced food intake, and altered metabolism. To better define the effects of VPAC1R on body phenotype, energy/glucose homeostasis, and metabolism, we conducted a 12-week study in a VPAC1R null model. Our results reveal that VPAC1^−/− mice experienced significant metabolic alterations during the dark cycle with greater numbers of feeding bouts (p = 0.009), lower Total Energy Expenditure (p = 0.025), VO₂ (p = 0.029), and VCO₂ (p = 0.016); as well as during the light cycle with lower Total Energy Expenditure (p = 0.04), VO₂ (p = 0.044), and VCO₂ (p = 0.029). Furthermore, VPAC1^−/− mice had significantly higher levels of GLP-1 and PYY during fasting, and higher levels of GLP-1, glucagon leptin and PYY during postprandial conditions. In addition, VPAC1^−/− mice had lower levels of glucose at 60′ and 120′, as assessed by insulin tolerance test. In conclusion, this study supports a key role for VPAC1R in the regulation of body glucose/energy homeostasis and metabolism.

Efficiency of Resistant Starch and Dextrins as Prebiotics: A Review of the Existing Evidence and Clinical Trials

In well-developed countries, people have started to pay additional attention to preserving healthy dietary habits, as it has become common knowledge that neglecting them may easily lead to severe health impairments, namely obesity, malnutrition, several cardiovascular diseases, type-2 diabetes, cancers, hypertensions, and inflammations. Various types of functional foods were developed that are enriched with vitamins, probiotics, prebiotics, and dietary fibers in order to develop a healthy balanced diet and to improve the general health of consumers. Numerous kinds of fiber are easily found in nature, but they often have a noticeable undesired impact on the sensory features of foods or on the digestive system. This led to development of modified dietary fibers, which have little to no impact on taste of foods they are added to. At the same time, they possess all the benefits similar to those of prebiotics, such as regulating gastrointestinal microbiota composition, increasing satiety, and improving the metabolic parameters of a human. In the following review, the evidence supporting prebiotic properties of modified starches, particularly resistant starches and their derivatives, resistant dextrins, was assessed and deliberated, which allowed drawing an interesting conclusion on the subject.

Appetite-regulating hormone trajectories and relationships with fat mass development in term-born infants during the first 6 months of life

Background

The first 6 months of life are a critical window for adiposity programming. Appetite-regulating hormones (ARH) are involved in food intake regulation and might, therefore, play a role in adiposity programming. Studies examining ARH in early life are limited.

Purpose

To investigate ghrelin, peptide YY (PYY) and leptin until 6 months and associations with fat mass percentage (FM%), infant feeding and human milk macronutrients.

Procedures

In 297 term-born infants (Sophia Pluto Cohort), ghrelin (acylated), PYY and leptin were determined at 3 and 6 months, with FM% measurement by PEAPOD. Exclusive breastfeeding (BF) was classified as BF ≥ 3 months. Human milk macronutrients were analyzed (MIRIS Human Milk Analyzer).

Main findings

Ghrelin increased from 3 to 6 months (p < 0.001), while PYY decreased (p < 0.001), resulting in increasing ghrelin/PYY ratio. Leptin decreased. Leptin at 3 months was higher in girls, other ARH were similar between sexes. Leptin at 3 and 6 months correlated with FM% at both ages(R ≥ 0.321, p ≤ 0.001) and gain in FM% from 1 to 6 months(R ≥ 0.204, p = 0.001). In BF infants, also ghrelin and ghrelin/PYY ratio correlated with this gain in FM%. Exclusively BF infants had lower ghrelin and higher PYY compared to formula fed infants at 3 months (p ≤ 0.039). ARH did not correlate with macronutrients.

Conclusions

Increasing ghrelin and decreasing PYY, thus increasing ghrelin/PYY ratio, suggests an increasing orexigenic drive until 6 months. ARH were different between BF and FF infants at 3 months, but did not correlate with human milk macronutrients. Ghrelin and leptin, but not PYY, correlated with more FM development during the first 6 months, suggesting that they might be involved in adiposity programming.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02533-z.

Gut Hormones in Health and Obesity: The Upcoming Role of Short Chain Fatty Acids

We are currently facing an obesity pandemic, with worldwide obesity rates having tripled since 1975. Obesity is one of the main risk factors for the development of non-communicable diseases, which are now the leading cause of death worldwide. This calls for urgent action towards understanding the underlying mechanisms behind the development of obesity as well as developing more effective treatments and interventions. Appetite is carefully regulated in humans via the interaction between the central nervous system and peripheral hormones. This involves a delicate balance in external stimuli, circulating satiating and appetite stimulating hormones, and correct functioning of neuronal signals. Any changes in this equilibrium can lead to an imbalance in energy intake versus expenditure, which often leads to overeating, and potentially weight gain resulting in overweight or obesity. Several lines of research have shown imbalances in gut hormones are found in those who are overweight or obese, which may be contributing to their condition. Therefore, this review examines the evidence for targeting gut hormones in the treatment of obesity by discussing how their dysregulation influences food intake, the potential possibility of altering the circulating levels of these hormones for treating obesity, as well as the role of short chain fatty acids and protein as novel treatments.

An Overview of the Pathophysiology of Metabolic Changes and Their Sequence of Occurrence in Obese Diabetic Females: A Narrative Review

Obesity and diabetes both mediate their effects through insulin resistance and frequently co-exist. Insulin resistance is one of the key factors in the development of the metabolic syndrome. Adult females tend to develop obesity more frequently than males. One of the factors causing this difference is the pattern of changes that occur as females age from pre-menopausal to the post-menopausal stage, causing a change in the pattern of accumulation of fats. Several studies have explored and described the association between obesity and metabolic syndrome and their effect on type II diabetes. We conducted our literature search using PubMed and Google Scholar as our primary databases. We selected a total of 49 articles for review after applying the inclusion and exclusion criteria and removing the duplicate articles. We chose the full-text articles that were published in the English language only. The selected studies were randomized controlled trials and review papers. The reviewed articles showed that visceral fat, central obesity, and fasting blood sugar of post-menopausal is higher than in pre-menopausal women and needs adequate management. More studies are needed in the future to explore the patterns of the metabolic changes in obese females to provide early and better management of diabetes and prevent related complications.

Effects of Flavanols on Enteroendocrine Secretion

Some beneficial effects of grape seed proanthocyanidin extract (GSPE) can be explained by the modulation of enterohormone secretion. As GSPE comprises a combination of different molecules, the pure compounds that cause these effects need to be elucidated. The enterohormones and chemoreceptors present in the gastrointestinal tract differ between species, so if humans are to gain beneficial effects, species closer to humans-and humans themselves-must be used. We demonstrate that 100 mg/L of GSPE stimulates peptide YY (PYY) release, but not glucagon-like peptide 1 (GLP-1) release in the human colon. We used a pig ex vivo system that differentiates between apical and basolateral intestinal sides to analyse how apical stimulation with GSPE and its pure compounds affects the gastrointestinal tract. In pigs, apical GSPE treatment stimulates the basolateral release of PYY in the duodenum and colon and that of GLP-1 in the ascending, but not the descending colon. In the duodenum, luminal stimulation with procyanidin dimer B2 increased PYY secretion, but not CCK secretion, while catechin monomers (catechin/epicatechin) significantly increased CCK release, but not PYY release. The differential effects of GSPE and its pure compounds on enterohormone release at the same intestinal segment suggest that they act through chemosensors located apically and unevenly distributed along the gastrointestinal tract.

Abnormal Uroguanylin Immunoreactive Cells Density in the Duodenum of Patients with Diarrhea-Predominant Irritable Bowel Syndrome Changes following Fecal Microbiota Transplantation

Altered densities of enteroendocrine cells play an important role in patients with irritable bowel syndrome (IBS). Uroguanylin activates guanylate cyclase-C to regulate intestinal electrolyte and water transport. Aim. To quantify uroguanylin immunoreactive cells density in the duodenum of diarrhea-predominant IBS (IBS-D) patients compared to controls and to investigate the effect of fecal microbiota transplantation (FMT) on these cell densities. Method. Twelve patients with IBS-D according to Rome III criteria were included. The cause was identified as post infectious (PI, n = 6) or idiopathic (n = 6). They completed the IBS-symptom questionnaire before and 3 weeks after FMT. Thirty grams of fresh feces donated from healthy relatives were diluted with 60 ml normal saline and instilled via endoscope into the duodenum. Biopsies were taken from the patients' duodenum before and 3 weeks after FMT. Duodenal biopsies taken from eight healthy controls were also included. The biopsies were immunostained for uroguanylin and quantified using computerized image analysis. Results. Uroguanylin immunoreactive cells were found both in duodenal villi and crypts in both controls and IBS-D patients. The densities of uroguanylin immunoreactive cells were significantly lower in the villi (P < 0.0001) and higher in the crypts (P < 0.0001) for the patients than the controls. Following FMT, the densities of uroguanylin immunoreactive cells for the total group and idiopathic subgroup decreased significantly in the duodenal crypts (P = 0.049 and 0.04, respectively) but not in the villi. No significant changes were shown in the PI-IBS subgroups. The cells density in only the crypts correlated with diarrhea (r = 0.97, P = 0.001) and bloating (r = -0.91, P = 0.01) in the PI-IBS subgroup before FMT and with abdominal pain (r = 0.63, P = 0.03) in the total group of IBS-D patients after FMT. Conclusion. Altered uroguanylin immunoreactive cells density was found in IBS-D patients compared to controls. Changes in these cells density following FMT correlated with IBS symptoms (diarrhea, bloating, and abdominal pain).

Appetite-regulating hormones and anthropometric indicators of infants according to the type of feeding

It has been accepted that satiety- and appetite-stimulating hormones play a role in the regulation of food intake and body composition during and after the lactation stage. Therefore, the purpose was to demonstrate that serum appetite-regulating hormones in infants differ according to anthropometric indicators and type of feeding. In a nonrandom cohort study, 169 mother-newborn dyads whose pregnancy and birth were attended at the Hospital Civil de Guadalajara were enrolled. According to the type of feeding, infants were classified as full breastfeeding (FBF), partial breastfeeding (PBF), and infants receiving human milk substitutes (HMS). Serum concentrations of ghrelin (pg/ml), leptin (ng/ml), peptide YY (pg/ml), and glucagon-like peptide-1 (GLP-1) (pM) were measured. Anthropometric measurements including weight, length, cephalic, arm circumference, tricipital, and subscapular skinfolds were obtained. Weight/age, weight/height, height/age, and BMI Z-score indexes were estimated. We performed one-way ANOVA, unpaired Student's t test, post hoc Tukey test, and Pearson correlation tests. The ANOVA comparison of the three feeding types showed significant differences in most anthropometric indicators (z-scores), especially between infants receiving FBF versus HMS and particularly on indicators of adiposity; no differences were observed in length and cephalic circumference z-scores at 8th and 16th weeks. Further, significant correlations were found between most of the adiposity indicators with ghrelin, leptin, and GLP-1, especially in infants who received FBF. There were differences in anthropometric and body composition parameters among infants receiving FBF, PBF, and HMS. There were significant correlations between body composition indicators with ghrelin, leptin, and GLP-1 mainly in infants receiving FBF.

Concentration of ghrelin and leptin in serum and human milk in nursing mothers according to the type of feeding

INTRODUCTION

Objective: we assessed the relationship between serum and human foremilk and hindmilk concentrations of ghrelin and leptin in nursing mothers according to the type of feeding. Methods: this cohort design was carried out on 131 mother-newborn dyads admitted to a physiological puerperium ward. The independent variables were the type of feeding, full breastfeeding (FBF, 56.5%) and partial breastfeeding (PBF, 43.5%). The dependent variables were the concentration of total ghrelin (pg/ml) and leptin (ng/ml) in serum, foremilk and hindmilk at eight and 16 weeks. Fasting blood samples were obtained from the nursing mothers at four months for serum assays. Unpaired Student's t-test, Mann-Whitney U test, Pearson's correlation tests, coefficient of determination and linear regression were used. Results: the concentration of ghrelin and leptin in hindmilk was higher than that of foremilk in both groups at eight and 16 weeks. The concentration of ghrelin and leptin was higher in serum than in foremilk in both groups. These values showed a direct and significant linear correlation with the exception of ghrelin in the FBF group. The serum concentration of leptin in mothers explained 32% of the variance of its concentration in foremilk in the FBF and 13% in the PBF groups. Conclusion: the hindmilk/foremilk gradient suggests an intake regulating mechanism during the fed. The concentration of ghrelin and leptin was higher in the serum than in foremilk and its correlation and determination coefficients could suggest plasma-milk transfer in addition to synthesis regulation by the mammary gland, adipose tissue or other organs.

A Comparison of Gastric and Jejunal Feeding in Hypercatabolism Associated With Hypothalamic AMPK-Autophagy-POMC in Endotoxemic Rats

BACKGROUND

Hypercatabolism is associated with increased infectious rates and mortality in critically ill patients. Enteral nutrition (EN) is usually used to counteract hypercatabolism. However, the impact of different routes of EN on hypercatabolism remains unknown. Here, we compared the impact of gastric feeding (GF) and jejunal feeding (JF) on gastrointestinal hormones and hypercatabolism, which is associated with hypothalamic adenosine 5'-monophosphate-activated protein kinase (AMPK)-autophagy-proopiomelanocortin (POMC).

METHODS

Sixty adult male Sprague-Dawley rats were divided into 5 groups: Sham and lipopolysaccharide (LPS) groups fed a standard chow diet, a pair-fed group that was a subset of saline-treated rats pair-fed with the LPS group, and LPS + JF and LPS + GF groups (received EN via jejunal and gastric tube, respectively, for 3 days [100 kcal/kg/d]). Hypercatabolism was measured by insulin resistance, muscle protein synthesis, and atrophy. Serum gastrointestinal hormones, hypothalamic ghrelin, growth hormone secretagogue receptor-1α (GHS-R1α), and AMPK-autophagy-POMC markers were also detected.

RESULTS

GF increased serum total, acylated, desacylated, and hypothalamic ghrelin and decreased glucagon-like peptide-1 (GLP-1). But no effect on pancreatic polypeptide (PYY) and hypothalamic GHS-R1α was observed. JF showed no effect on hypothalamic ghrelin, GHS-R1α, and serum total, acylated, and desacylated ghrelin and even further aggravated GLP-1 and PYY. GF could effectively augment hypothalamic AMPK-autophagy-POMC and hypercatabolism. However, JF showed no effect on hypothalamic AMPK-autophagy-POMC and hypercatabolism.

CONCLUSIONS

GF could activate hypothalamic AMPK-autophagy and suppress POMC expression via gastrointestinal hormones to ameliorate hypercatabolism compared with JF, which suggested that GF may be the preferred route of EN in endotoxemic rats.

Meal-Related Acyl and Des-Acyl Ghrelin and Other Appetite-Related Hormones in People with Obesity and Binge Eating

OBJECTIVE

Potential mechanisms of abnormal food intake, such as dysregulation of meal-related appetite hormones, including acyl ghrelin (AG) and des-acyl ghrelin (DAG), were investigated among men and women with obesity, with and without binge eating (BE).

METHODS

Participants (n = 42: 19 female, 23 male) were assigned to a liquid meal and water condition in counterbalanced order, and blood samples for measuring hormones were obtained before and after these conditions.

RESULTS

Participants with BE had significantly lower fasting and postingestive AG concentrations than participants without BE in both conditions. During the meal condition, postprandial decreases in AG concentrations were significantly smaller for the BE group than for the non-BE group. There were no significant differences in DAG by BE group. Leptin increased significantly less after meals for those with BE compared with those without BE. There were no differences in other hormones by BE group. Fasting and postmeal hunger ratings were significantly higher for those with BE than for those without BE.

CONCLUSIONS

In individuals with BE, lower fasting AG may be due to downregulation by habitual overeating, and a smaller postmeal decline in AG may contribute to overeating. Lower postmeal leptin concentrations may also contribute to overeating.

Physiology of energy homeostasis: Models, actors, challenges and the glucoadipostatic loop

The aim of this review is to discuss the physiology of energy homeostasis (EH), which is a debated concept. Thus, we will see that the set-point theory is highly challenged and that other models integrating an anticipative component, such as energy allostasis, seem more relevant to experimental reports and life preservation. Moreover, the current obesity epidemic suggests that EH is poorly efficient in the modern human dietary environment. Non-homeostatic phenomena linked to hedonism and reward seem to profoundly impair EH. In this review, the apparent failed homeostatic responses to energy challenges such as exercise, cafeteria diet, overfeeding and diet-induced weight loss, as well as their putative determinants, are analyzed to highlight the mechanisms of EH. Then, the hormonal, neuronal, and metabolic factors of energy intake or energy expenditure are briefly presented. Last, this review focuses on the contributions of two of the most pivotal and often overlooked determinants of EH: the availability of endogenous energy and the pattern of energy intake. A glucoadipostatic loop model is finally proposed to link energy stored in adipose tissue to EH through changes in eating behavior via leptin and sympathetic nervous system activity.

Association Between Single Nucleotide Polymorphisms in PPARA and EPAS1 Genes and High-Altitude Appetite Loss in Chinese Young Men

Appetite loss is a common symptom that occurs in high altitude (HA) for lowlanders. Previous studies indicated that hypoxia is the initiating vital factor of HA appetite loss. PPARA, EPAS1, EGLN1, HIF1A, HIF1AN, and NFE2L2 play important roles in hypoxic responses. We aimed to explore the association of these hypoxia-related gene polymorphisms with HA appetite loss. In this study, we enrolled 416 young men who rapidly ascended to Lhasa (3700 m) from Chengdu (<500m) by plane. PPARA, EPAS1, EGLN1, HIF1A, HIF1AN, and NFE2L2 were genotyped by MassARRAY. Appetite scores were measured to identify HA appetite loss. Logistic regression and multiple genetic models were tested to evaluate the association between the single nucleotide polymorphisms (SNPs) and risk of HA appetite loss in crude and adjusted (age and SaO₂) analysis. Subsequently, Haploview software was used to analyze the linkage disequilibrium (LD), haplotype construction and the association of diverse haplotypes with the risk of HA appetite loss. Our results revealed that allele “A” in PPARA rs4253747 was significantly associated with the increased risk of HA appetite loss. Codominant, dominant, recessive, and log-additive models of PPARA rs4253747 showed the increased risk of HA appetite loss in the crude and adjusted analysis. However, only dominant, overdominant, and log-additive models of EPAS1 rs6756667 showed decreased risk of HA appetite loss in the crude and adjusted analysis. Moreover, the results from haplotype-based test showed that the rs7292407-rs6520015 haplotype “AC” was associated with HA appetite loss in the crude analysis rather than the adjusted analysis. In this study, we first established the association of SNPs in PPARA (rs4253747) and EPAS1 (rs6756667) genes with susceptibility to HA appetite loss in Han Chinese young men. These findings provide novel insights into understanding the mechanisms involved in HA appetite loss.

Serum concentration of appetite-regulating hormones of mother-infant dyad according to the type of feeding

Satiety and appetite-stimulating hormones play a role in the regulation of food intake. Breastfed infants may have a different profile of serum appetite-regulating hormones than formula-fed infants. We propose to demonstrate that the serum concentration of appetite regulatory hormones differs according to the type of feeding and that there is a correlation between the serum concentrations of these hormones in mothers and in infants at 4 months of age. In a cross-sectional analysis, 167 mother-newborn dyads at the Hospital Civil de Guadalajara were enrolled: 74 full breastfeeding (FBF), 56 partial breastfeeding (PBF), and 37 receiving human milk substitutes (HMS). Serum levels of ghrelin (pg/ml), leptin (ng/ml), peptide YY (pg/ml), and glucagon-like peptide-1 (GLP-1) (pM) were measured. We performed one-way analysis of variance, unpaired Student t test, post hoc Tukey test, and Pearson correlation. The total sample at 16 weeks postpartum included 167 dyads. The mean age was 16 ± 1 weeks. The concentrations of GLP-1 (pM) and peptide YY (pg/ml) were higher in the FBF group (42.6 and 442.9) than in the HMS group (35.2 and 401.9), respectively, p = 0.046 and p = 0.056. And, the FBF group had higher correlation coefficients of ghrelin (r = 0.411 vs. 0.165), GLP-1 (r = 0.576 vs. 0.407), and peptide YY (r = 0.218 vs. 0.067), respectively, than the HMS group. The concentrations of GLP-1 and peptide YY were higher in the FBF group when compared with the HMS group. Mother-infant dyads fed by FBF had more significant direct correlations of appetite-regulating hormones than those who received HMS.

Impact of Pre-Processed Chickpea Flour Incorporation into "Mankoushe" on Appetite Hormones and Scores

Recently, there has been an increasing interest in integrating pulse flours into pastries and baked products to improve their nutritional and health benefits. "Mankoushe," a popular Lebanese pastry made up of refined wheat flour was enriched with chickpea flour that is of better nutritional value, and its postprandial glycemia, insulinemia, lipidemia and appetite measures were monitored. A randomized cross-over study was performed on sixteen healthy Lebanese females, age (years): 22.90 ± 3.00, and BMI (kg/m²): 22.70 ± 2.65. Over-night fasted females were asked to consume two iso-energetic meals (201 g; 681 kcal) on two separate days, three days apart. One meal was the "Regular Mankoushe" (RM) made with white flour 100%, and the second meal was the "Chickpeas Mankoushe" (CM) made with a mixture of wheat/chickpea flour (70/30). Blood samples were collected 15 min before meal ingest and at 30, 90, 150 and 210 min postprandial. Glucose, insulin, triglycerides (TG), ghrelin, and glucagon-like peptide 1 (GLP-1) plasma levels were measured. Subjective appetite rating and food intake were also assessed. Incorporation of pre-processed chickpea flour into "Mankoushe" as 30% of the dough was associated with a modest reduction in both glucose and insulin levels, and TG was minimally affected. At the level of appetite hormones, changes in GLP-1 were similar, whereas the reduction in ghrelin was significantly lower after the RM meal and thus favored a higher satiating effect compared to CM. This was not paralleled by a similar change in subjective appetite scores and subsequent energy intake. In conclusion, findings suggest that pre-processed chickpea flour could be a promising functional ingredient of traditional pastries to improve their nutritional quality. Nevertheless, further investigations are warranted regarding its satiating effect.

Role of the gut, melanocortin system and malonyl-CoA in control of feed intake in non-ruminant animals

Regulation of feed intake is under complex control, involving physical, chemical, hormonal and neuronal responses. Understanding the regulation of feed intake in farm animals is key to optimisation of intake to meet production and profitability goals. Fundamental mechanisms regulating feed intake include constraints imposed by the gut, systems monitoring current and long-term energy status to increase or decrease intake, and hedonic, reward-related drives. Feed intake is closely related to the rate of passage of digesta and the capacity of the gastrointestinal tract. Indigestible fibre increases the rate of digesta passage and feed intake until excess distension sends signals of satiety to the brain. The presence of partially digested nutrients and products of microbial fermentation in the distal intestines releases peptides (PYY, OXM, GPL-1, Apo A-IV, amylin) from gut and pancreas to activate the intestinal brake, which slows the rate of passage and reduces feed intake. These peptides also act on orexigenic (NPY, AgRP) and anorexigenic (POMC, CART) peptides of the melanocortin system of the hypothalamus to reduce intake over the long term. Immediate energy status of the animal is monitored through the ratio of AMP : ATP via adenosine monophosphate-activated kinase and mammalian target of rapamycin, whereas the overall animal energy status is monitored by insulin, leptin and ghrelin. These energy-monitoring systems control short- and long-term intakes through the melanocortin system of the hypothalamus, primarily via malonyl-CoA, to alter the relative expression of orexigenic and anorexigenic peptides. Gut and hypothalamic control of feed intake can be over-ridden by hedonic, reward-related centres of the brain, predominantly through the release of dopamine. These hedonic responses can lead to over-consumption and obesity under some circumstances or reduced feed intake under stressful or other negative environmental situations. Knowledge of these mechanisms can be used to identify practical strategies for either increasing or decreasing voluntary intake in pigs.

Short-chain fatty acids in control of energy metabolism

Short-chain fatty acids (SCFAs), especially acetate, propionate and butyrate, are the end products from the intestinal microbial fermentation of dietary fibers and resistant starch. It has been well documented that plasma and colonic SCFAs are associated with metabolic syndromes. Recently, the involvement of SCFAs in energy homeostasis regulation has been extensively studied. The importance of SCFAs on energy metabolism has highlighted the potential of modulating SCFAs as a nutritional target to prevent and counteract metabolism disorders and its associated diseases such as obesity and type 2 diabetes. Here, we summarize the current knowledge about the biological properties of SCFAs with their impact on the energy homeostasis.

Metabolism disrupting chemicals and metabolic disorders

The recent epidemics of metabolic diseases, obesity, type 2 diabetes(T2D), liver lipid disorders and metabolic syndrome have largely been attributed to genetic background and changes in diet, exercise and aging. However, there is now considerable evidence that other environmental factors may contribute to the rapid increase in the incidence of these metabolic diseases. This review will examine changes to the incidence of obesity, T2D and non-alcoholic fatty liver disease (NAFLD), the contribution of genetics to these disorders and describe the role of the endocrine system in these metabolic disorders. It will then specifically focus on the role of endocrine disrupting chemicals (EDCs) in the etiology of obesity, T2D and NAFLD while finally integrating the information on EDCs on multiple metabolic disorders that could lead to metabolic syndrome. We will specifically examine evidence linking EDC exposures during critical periods of development with metabolic diseases that manifest later in life and across generations.

Concentrations of prealbumin and some appetite-controlling hormones in pregnancies associated with hyperemesis gravidarium

Background Hyperemesis gravidarum, which affects 0.3-2.3% of pregnancies, is defined as excessive vomiting during pregnancy and usually starts in week 4 or 5 of gestation. Symptoms include weight loss, dehydration, ketonaemia, ketonuria, fasting acidosis, alkalosis due to hydrochloric acid loss and hypokalaemia and its exact cause is unknown. The present study was undertaken to investigate the relationship between prealbumin, ghrelin, nesfatin-1 and obestatin concentrations in pregnancies associated with hyperemesis gravidarum. Methods A total of 40 pregnant females with hyperemesis gravidarum and 38 pregnant females without hyperemesis gravidarum as controls were included in this study. Serum concentrations of prealbumin, ghrelin, obestatin and nesfatin-1 were measured. Results There were no significant differences in age, gestational week, gravidity and parity between the two groups. Body mass index was significantly lower in cases than in controls. Serum ghrelin and prealbumin concentrations were significantly lower in cases than in controls ( P  <0.05 and P < 0.001, respectively). There was no significant difference in serum concentrations of obestatin and nesfatin-1 between the two groups. There was no significant association between body mass index and serum ghrelin, nesfatin-1, obestatin or prealbumin concentrations in patients with hyperemesis gravidarum. Conclusions Decreased serum concentrations of ghrelin and prealbumin in patients with hyperemesis gravidarum are independent of body mass index. Based on our results, we believe that ghrelin may be considered to play a role in the aetiopathogenesis of hyperemesis gravidarum and that hyperemesis gravidarum may result in disruption of the relationship between nesfatin-1 and ghrelin. In addition, we believe that the measurement of serum prealbumin may be used for assessing nutritional status in pregnancy.

Long-term Outcome after Robotic-assisted Gastroplication in Adolescents: Hunger Hormone and Food Preference Changes Two Case Reports

Weight loss surgery (WLS) is efficacious for long-term weight reduction and decreases overall mortality in severely obese patients. The mechanisms implicated in long-term weight loss are not fully understood. Proposed mechanisms include changes in gut hormones and brain regulation of appetite and satiety. We aimed to investigate the long-term ghrelin and leptin profiles and changes in food preference and eating behavior after WLS in adolescent patients. Two obese females aged 15 years and 14 4/12 years, who did not respond to lifestyle changes, including dietary intervention and physical exercise in combination with medical therapy, underwent robotic-assisted gastroplication. Anthropometric measurements, food habits and eating behavior, as well as metabolic and hormonal changes during long-term post-surgical follow-up were monitored. Long-term weight reduction was obtained in both patients, with a significant decrease in waist circumference. Resting energy expenditure showed a decrease over time, with a respiratory quotient that increased showing a shift from oxidation of a high-fat diet before surgery to oxidation of a mixed diet two and three years later. Both subjects improved their eating habits and lifestyle. Co-morbidity resolution was also noted. Increased pre-prandial ghrelin levels as well as higher post-prandial ghrelin and a leptin drop compared with pre-surgery values were observed in both patients. Persistent weight loss after gastroplication is associated with a favorable change in gut hormones and food preferences. The role of hormonal and sensory components in long-term results seems crucial. Particularly in adolescent patients, a multidisciplinary approach and continuous nutritional care is mandatory for weight maintenance and consolidation of changes.

Appetite-regulating hormones in early life and relationships with type of feeding and body composition in healthy term infants

Introduction

Body composition in early life influences development of obesity during childhood and beyond. Appetite-regulating hormones (ARH) play a role in regulation of food intake and might thus influence body composition in later life. Studies on associations between ARH and body composition in early life are limited.

Methods

In 197 healthy term infants, we measured serum fasting levels of ghrelin, leptin, insulin, glucose-dependent insulinotropic peptide (GIP), pancreatic polypeptide (PP) and peptide YY (PYY) at 3 months and in 41 infants also at 6 months and their associations with type of feeding and longitudinal fat mass percentage (FM%) measured by air displacement plethysmography at 1, 3 and 6 months and abdominal visceral and subcutaneous fat, measured by ultrasound, at 3 and 6 months.

Results

Infants with formula feeding for 3 months had significantly higher serum levels of ghrelin, leptin, insulin, GIP and PP (p = 0.026, p = 0.018, p = 0.002, p < 0.001, resp.) and lower serum levels of PYY (p = 0.002) at 3 months than breastfed infants. Leptin and ghrelin correlated positively with FM% at 3 months and insulin with change in FM% between 1 and 3 months (r = 0.40, p < 0.001, r = 0.23, p < 0.05, r = 0.22, p < 0.01, resp.). Leptin at 3 months correlated with subcutaneous fat at 3 months (r = 0.23, p < 0.001), but not with visceral fat. Other ARH did not correlate with body composition.

Conclusion

Formula-fed infants had a different profile of ARH than breastfed infants, suggesting that lower levels of ghrelin, leptin and insulin in breastfed infants contribute to the protective role of breastfeeding against obesity development. Leptin, ghrelin and insulin were associated with fat mass percentage or its changes.

Impact of [d-Lys(3)]-GHRP-6 and feeding status on hypothalamic ghrelin-induced stress activation

Ghrelin administration directly into hypothalamic nuclei, including the arcuate nucleus (ArcN) and the paraventricular nucleus (PVN), alters the expression of stress-related behaviors. In the present study we investigated the effect of feeding status on the ability of ghrelin to induce stress and anxiogenesis. Adult male Sprague Dawley rats were implanted with guide cannula targeting either the ArcN or PVN. In the first experiment we confirmed that ArcN and PVN ghrelin treatment produced anxiety-like behavior as measured using the elevated plus maze (EPM) paradigm. Ghrelin was administered during the early dark cycle. Immediately after microinjections rats were placed in the EPM for 5min. Both ArcN and PVN treatment reduced open arm exploration. The effect was attenuated by pretreatment with the ghrelin 1a receptor antagonist [d-Lys(3)]-GHRP-6. In a separate group of animals ghrelin was injected into either nucleus and rats were returned to their home cages for 60min with free access to food. An additional group of rats was returned to home cages with no food access. After 60min with or without food access all rats were tested in the EPM. Results indicated that food consumption just prior to EPM testing reversed the avoidance of the open arms of the EPM. In contrast, rats injected with ghrelin, placed in their home cage for 60min without food, and subsequently tested in the EPM, exhibited an increased avoidance of the open arms, consistent with stress activation. Overall, our findings demonstrate that ghrelin 1a receptor blockade and feeding status appear to impact the ability of ArcN and PVN ghrelin to elicit stress and anxiety-like behaviors.

Hexarelin Protects Rodent Pancreatic Β-Cells Function from Cytotoxic Effects of Streptozotocin Involving Mitochondrial Signalling Pathways In Vivo and In Vitro

Mitochondrial functions are crucial for pancreatic β-cell survival and glucose-induced insulin secretion. Hexarelin (Hex) is a synthetic small peptide ghrelin analogue, which has been shown to protect cardiomyocytes from the ischemia-reperfusion process. In this study, we used in vitro and in vivo models of streptozotocin (STZ)-induced β-cell damage to study the protective effect of Hex and the associated mechanisms. We found that STZ produced a cytotoxic effect in a dose- and time-dependent manner in MIN6 cells (a mouse β-cell line). Hex (1.0 μM) decreased the STZ-induced damage in β-cells. Rhodamine 123 assay and superoxide DHE production assay revealed that Hex ameliorated STZ-induced mitochondrial damage and excessive superoxide activity in β-cells. In addition, Hex significantly reduced STZ-induced expression of cleaved Caspases-3, Caspases-9 and the ratio of pro-apoptotic protein Bax to anti-apoptotic protein Bcl-2 in MIN6 cells. We further examined the in vivo effect of Hex in a rat model of type 1 diabetes induced by STZ injection. Hex ameliorated STZ-induced decrease in plasma insulin and protected the structure of islets from STZ-induced disruption. Hex also ameliorated STZ-induced expression of cleaved Caspase-9 and the Bax in β-cells. In conclusion, our data indicate that Hex is able to protects β-cell mass from STZ-caused cytotoxic effects involving mitochondrial pathways in vitro and in vivo. Hex may serve as a potential protective agent for the management of diabetes.

Endocrine disruptors and obesity

The increasing incidence of obesity is a serious global public health challenge. Although the obesity epidemic is largely fueled by poor nutrition and lack of exercise, certain chemicals have been shown to potentially have a role in its aetiology. A substantial body of evidence suggests that a subclass of endocrine-disrupting chemicals (EDCs), which interfere with endocrine signalling, can disrupt hormonally regulated metabolic processes, especially if exposure occurs during early development. These chemicals, so-called 'obesogens' might predispose some individuals to gain weight despite their efforts to limit caloric intake and increase levels of physical activity. This Review discusses the role of EDCs in the obesity epidemic, the latest research on the obesogen concept, epidemiological and experimental findings on obesogens, and their modes of action. The research reviewed here provides knowledge that health scientists can use to inform their research and decision-making processes.

Functional foods as potential therapeutic options for metabolic syndrome

Obesity as part of metabolic syndrome is a major lifestyle disorder throughout the world. Current drug treatments for obesity produce small and usually unsustainable decreases in body weight with the risk of major adverse effects. Surgery has been the only treatment producing successful long-term weight loss. As a different but complementary approach, lifestyle modification including the use of functional foods could produce a reliable decrease in obesity with decreased comorbidities. Functional foods may include fruits such as berries, vegetables, fibre-enriched grains and beverages such as tea and coffee. Although health improvements continue to be reported for these functional foods in rodent studies, further evidence showing the translation of these results into humans is required. Thus, the concept that these fruits and vegetables will act as functional foods in humans to reduce obesity and thereby improve health remains intuitive and possible rather than proven.

Multiplexed Quantification of Proglucagon-Derived Peptides by Immunoaffinity Enrichment and Tandem Mass Spectrometry after a Meal Tolerance Test

BACKGROUND

Proglucagon-derived peptides (PGDPs), which include glucagon-like peptide (GLP)-1, glucagon, and oxyntomodulin, are key regulators of glucose homeostasis and satiety. These peptide hormones are typically measured with immuno-based assays (e.g., ELISA, RIA), which often suffer from issues of selectivity.

METHODS

We developed a multiplexed assay for measuring PGDPs including GLP-1 (7-36) amide, GLP-1 (9-36) amide, glucagon, and oxyntomodulin by mass spectrometry and used this assay to examine the effect of a meal tolerance test on circulating concentrations of these hormones. Participants fasted overnight and were either given a meal (n = 8) or continued to fast (n = 4), with multiple blood collections over the course of 3 h. Plasma samples were analyzed by microflow immunoaffinity (IA)-LC-MS/MS with an isotope dilution strategy.

RESULTS

Assay performance characteristics were examined and established during analytical validation for all peptides. Intra- and interassay imprecision were found to be 2.2%-10.7% and 6.8%-22.5%, respectively. Spike recovery was >76%, and dilution linearity was established up to a 16-fold dilution. Immediately after the meal tolerance test, GLP-1 and oxyntomodulin concentrations increased and had an almost identical temporal relationship, and glucagon concentrations increased with a slight delay.

CONCLUSIONS

IA-LC-MS/MS was used for the simultaneous and selective measurement of PGDPs. This work includes the first indication of the physiological concentrations and modulation of oxyntomodulin after a meal.