Ghrelin: much more than a hunger hormone

The Effectiveness of Nigella sativa and Ginger as Appetite Suppressants: An Experimental Study on Healthy Wistar Rats

Background

Obesity is a global pandemic that is associated with high morbidity and mortality. Natural herbs are commonly used for weight reduction and appetite suppression. Therefore, we aim to investigate the role and mechanism of Nigella sativa (NS) and ginger on weight reduction and appetite regulation.

Methods

This experimental study was performed at Imam Abdulrahman Bin Faisal University. Twenty-five female rats were distributed into 5 groups: NS (oral 1000mg/kg), Ginger (500 mg/kg), NS-ginger (both interventions), a positive control (intraperitoneal 50 μg/kg Liraglutide), and a negative control. Each intervention was given for 9 weeks. Food intake and body weight were assessed weekly. Serum lipid profile and peptides involved in appetite control (cholecystokinin (CCK), glucagon-like peptide 1(GLP-1), gastric inhibitory polypeptide (GIP), ghrelin, peptide YY, and orexin) were assayed at the end of the experiment.

Results

None of the interventions showed a statistically significant difference regarding food consumption or weight gain (p > 0.05). However, the three interventions significantly reduced total cholesterol (TC), NS and NS-ginger significantly increased HDL, NS increased ghrelin and ginger increased orexin.

Conclusion

The present dose and duration of NS, ginger, or in combination did not demonstrate a significant change in body weight or food consumption in comparison to the negative or positive controls. However, NS or ginger has improved the lipid profile by reducing TC and increasing HDL. In addition, NS or ginger can influence some of the peptides involved in appetite regulation such as the increase in ghrelin induced by NS and the reduction of orexin induced by ginger. We believe that these latter effects are novel and might indicate a promising effect of these natural products on appetite regulation.

Potential Applications for Growth Hormone Secretagogues Treatment of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) arises from neuronal death due to complex interactions of genetic, molecular, and environmental factors. Currently, only two drugs, riluzole and edaravone, have been approved to slow the progression of this disease. However, ghrelin and other ligands of the GHS-R1a receptor have demonstrated interesting neuroprotective activities that could be exploited in this pathology. Ghrelin, a 28-amino acid hormone, primarily synthesized and secreted by oxyntic cells in the stomach wall, binds to the pituitary GHS-R1a and stimulates GH secretion; in addition, ghrelin is endowed with multiple extra endocrine bioactivities. Native ghrelin requires esterification with octanoic acid for binding to the GHS-R1a receptor; however, this esterified form is very labile and represents less than 10% of circulating ghrelin. A large number of synthetic compounds, the growth hormone secretagogues (GHS) encompassing short peptides, peptoids, and non-peptidic moieties, are capable of mimicking several biological activities of ghrelin, including stimulation of GH release, appetite, and elevation of blood IGF-I levels. GHS have demonstrated neuroprotective and anticonvulsant effects in experimental models of pathologies both in vitro and in vivo. To illustrate, some GHS, currently under evaluation by regulatory agencies for the treatment of human cachexia, have a good safety profile and are safe for human use. Collectively, evidence suggests that ghrelin and cognate GHS may constitute potential therapies for ALS.

Mucosal and hormonal adaptations after Roux-en-Y gastric bypass

The aim of this study was to perform a comprehensive literature review regarding the relevant hormonal and histologic changes observed after Roux-en-Y gastric bypass (RYGB). We aimed to describe the relevant hormonal (glucagon-like peptides 1 and 2 [GLP-1 and GLP-2], peptide YY [PYY], oxyntomodulin [OXM], bile acids [BA], cholecystokinin [CCK], ghrelin, glucagon, gastric inhibitory polypeptide [GIP], and amylin) profiles, as well as the histologic (mucosal cellular) adaptations happening after patients undergo RYGB. Our review compiles the current evidence and furthers the understanding of the rationale behind the food intake regulatory adaptations occurring after RYGB surgery. We identify gaps in the literature where the potential for future investigations and therapeutics may lie. We performed a comprehensive database search without language restrictions looking for RYGB bariatric surgery outcomes in patients with pre- and postoperative blood work hormonal profiling and/or gut mucosal biopsies. We gathered the relevant study results and describe them in this review. Where human findings were lacking, we included animal model studies. The amalgamation of physiologic, metabolic, and cellular adaptations following RYGB is yet to be fully characterized. This constitutes a fundamental aspiration for enhancing and individualizing obesity therapy.

Ghrelin Alleviates Experimental Ulcerative Colitis in Old Mice and Modulates Colonocyte Metabolism via PPARγ Pathway

There is a growing prevalence of inflammatory bowel disease (IBD), a chronic inflammatory condition of the gastrointestinal tract, among the aging population. Ghrelin is a gut hormone that, in addition to controlling feeding and energy metabolism, has been shown to exert anti-inflammatory effects; however, the effect of ghrelin in protecting against colitis in old mice has not been assessed. Here, we subjected old female C57BL/6J mice to dextran sulfate sodium (DSS) in drinking water for six days, then switched back to normal drinking water, administered acyl-ghrelin or vehicle control from day 3 to 13, and monitored disease activities throughout the disease course. Our results showed that treatment of old mice with acyl-ghrelin attenuated DSS-induced colitis. Compared to the DSS group, ghrelin treatment decreased levels of the inflammation marker S100A9 in the colons collected on day 14 but not on day 8, suggesting that the anti-inflammatory effect was more prominent in the recovery phase. Ghrelin treatment also significantly reduced F4/80 and interleukin-17A on day 14. Moreover, acyl-ghrelin increased mitochondrial respiration and activated transcriptional activity of the peroxisome proliferator-activated receptor gamma (PPARγ) in Caco-2 cells. Together, our data show that ghrelin alleviated DSS-induced colitis, suggesting that ghrelin may promote tissue repair in part through regulating epithelial metabolism via PPARγ mediated signaling.

Chicken LEAP2 Level Substantially Changes with Feed Intake and May Be Regulated by CDX4 in Small Intestine

Ghrelin O-acyltransferase (GOAT), ghrelin, and GHSR have been reported to play important roles that influence feed intake in mammals. LEAP2, an endogenous antagonist of GHSR, plays an important role in the regulation of feed intake. However, chicken ghrelin has also been reported to have an inhibitory effect on feed intake. The role of the GOAT-Ghrelin-GHSR-LEAP2 axis in chicken-feed intake remains unclear. Therefore, it is necessary to systematically evaluate the changes in the tissue expression levels of these genes under different energy states. In this study, broiler chicks in different energy states were subjected to starvation and feeding, and relevant gene expression levels were measured using quantitative real-time PCR. Different energy states significantly modulated the expression levels of LEAP2 and GHSR but did not significantly affect the expression levels of GOAT and ghrelin. A high expression level of LEAP2 was detected in the liver and the whole small intestine. Compared to the fed group, the fasted chicks showed significantly reduced LEAP2 expression levels in the liver and the small intestine; 2 h after being refed, the LEAP2 expression of the fasted chicks returned to the level of the fed group. Transcription factor prediction and results of a dual luciferase assay indicated that the transcription factor CDX4 binds to the LEAP2 promoter region and positively regulates its expression. High expression levels of GHSR were detected in the hypothalamus and pituitary. Moreover, we detected GHSR highly expressed in the jejunum-this finding has not been previously reported. Thus, GHSR may regulate intestinal motility, and this aspect needs further investigation. In conclusion, this study revealed the function of chicken LEAP2 as a potential feed-intake regulator and identified the potential mechanism governing its intestine-specific expression. Our study lays the foundations for future studies on avian feed-intake regulation.

Ghrelin level as a biomarker for knee osteoarthritis severity and appearance in HIV + patients

BACKGROUND

Knee Osteoarthritis (KOA) is a multifactorial disease with several mechanisms to promote articular cartilage damage. New molecules, such as ghrelin, have been recently reported to participate in the pathogenesis and progression of KOA. In HIV + patients, arthralgias are the most frequent musculoskeletal manifestations, mainly affecting joints such as the knee. Also, it has been reported that HIV + patients have a reduction of ghrelin even with treatment compared to HIV- patients. However, there is no report in the literature evaluating ghrelin and KOA in the HIV + population. We aimed to evaluate whether serum ghrelin levels can function as a biomarker for OA in HIV + patients.

METHODS

We recruited 40 patients, 20 HIV+, and 20 HIV- controls, and grouped as follows: HIV+/KOA+; HIV+/KOA-; HIV-/KOA+; HIV-/KOA-. Clinical features were obtained during clinical visits. Peripheral blood samples were acquired to measure serum ghrelin levels.

RESULTS

The HIV+/KOA + group significantly reduced serum ghrelin levels when compared with the other groups. Comparing the ghrelin levels with the patients' nadir of CD4⁺ T-cells count, we identified a statistically significant negative correlation in the KOA- group (r = -0.80, P < 0.007). An ROC curve analysis, for the accuracy of ghrelin levels to identified HIV+/KOA + from HIV+/KOA- patients, found an area under the curve of 0.83 (95 % CI 0.65-0.10; P = 0.017), with a cut-off < 4026 pg/mL serum ghrelin levels, with a sensitivity of 0.62 (95 % CI 0.32-0.86), and a specificity of 0.10 (95 % CI 0.59-0.10).

CONCLUSION

This study shows the potential use of ghrelin levels as a biomarker for KOA in the high-risk HIV population that should be further analyzed.

The expression and function of growth hormone secretagogue receptor in immune cells: A current perspective

The orexigenic hormone ghrelin and its receptor, growth hormone secretagogue receptor (GHS-R), have been extensively studied in the last two decades, revealing that ghrelin signaling has important implications in health and disease. Metabolic diseases, such as obesity and diabetes, are often accompanied by low-grade chronic inflammation, that has been coined as "meta-inflammation." Immune cells are key cellular mediators of meta-inflammation, controlling both initiation and resolution of inflammation. Immune cells exhibit dynamic changes in cellular characteristics and functional output in response to the stimuli/insults from their surrounding microenvironment. Emerging evidence shows that ghrelin has an important effect on inflammation, in addition to its well-known effects on metabolism. However, the cellular/molecular mechanism of ghrelin signaling in immunity is largely unknown because the knowledge in regard to the expression and function of GHS-R in immune cells is currently sparse. In this review, we have accumulated the recent findings related to the expression and functions of GHS-R in various immune cells under different physiological and pathological states. This review aims to inspire further investigation of the immunological roles of ghrelin signaling and advance the therapeutic applications of ghrelin signaling in meta-inflammation.

Physiology of the Weight-Reduced State and Its Impact on Weight Regain

Obesity is a chronic disease characterized by long duration, slow progression, and periods of remission and relapses. Despite the development of effective medical and surgical interventions and millions of people conducting tremendous personal efforts to manage their weight every year, recidivism remains a significant barrier to attaining long-term weight maintenance. This review aimed to explain the underlying physiology of the weight-reduced state including changes in energy balance, adipose tissue, genetic, environmental, and behavioral factors that may predispose individuals to weight regain following weight loss.

The Burden of Peripheral Neuropathy in Nondiabetic Chronic Kidney Disease and the Role of Ghrelin Isoforms in its Development

Introduction

Peripheral neuropathy is one of the most common complications in chronic kidney disease (CKD). The neuroprotective role of ghrelin is being explored recently. Here we aim to determine the burden of neuropathy in nondiabetic CKD and to find the association of peripheral nerve function with plasma ghrelin levels in these patients.

Methods

This was a cross-sectional study conducted in nondiabetic CKD patients on conservative management to determine the magnitude of neuropathy. The association of ghrelin isoforms with nerve functions was assessed between three groups, namely CKD with neuropathy, CKD without neuropathy, and healthy volunteers, with 20 participants in each group.

Results

The proportion of neuropathy in nondiabetic CKD was 78% (n = 78), of which 51% (n = 40) were asymptomatic. Des acyl ghrelin (DAG) and total ghrelin (TG) levels were 1545.5 ± 487.4 and 1567.4 ± 485.3 pg/mL, respectively, in CKD patients with neuropathy and were found to be elevated compared to those without neuropathy, who had 1000.4 ± 264.2 and 1019.7 ± 264.3 pg/mL of DAG and TG, respectively (P < 0.001). Assessment of correlation between nerve conduction parameters and DAG levels showed positive correlation between DAG levels and common peroneal latency (r = 0.69; P < 0.01), median sensory latency (r = 0.45; P < 0.05), and sural latency (r = 0.51; P < 0.05). We found negative correlation between median velocity (r =-0.56; P < 0.05), common peroneal velocity (r = -0.64; P < 0.01), median sensory velocity (r =-0.49; P < 0.05), and sural velocity (r = -0.54; P < 0.05). There was no statistically significant difference in acyl ghrelin levels among the groups.

Conclusion

The prevalence of peripheral neuropathy in CKD is significantly higher with almost half of them being asymptomatic. Impaired renal clearance in CKD leads to the accumulation of DAG, which subsequently inhibits the neuroprotective functions of AG leading to neuropathy in CKD.

Class A and C GPCR Dimers in Neurodegenerative Diseases

Neurodegenerative diseases affect over 30 million people worldwide with an ascending trend. Most individuals suffering from these irreversible brain damages belong to the elderly population, with onset between 50 and 60 years. Although the pathophysiology of such diseases is partially known, it remains unclear upon which point a disease turns degenerative. Moreover, current therapeutics can treat some of the symptoms but often have severe side effects and become less effective in long-term treatment. For many neurodegenerative diseases, the involvement of G proteincoupled receptors (GPCRs), which are key players of neuronal transmission and plasticity, has become clearer and holds great promise in elucidating their biological mechanism. With this review, we introduce and summarize class A and class C GPCRs, known to form heterodimers or oligomers to increase their signalling repertoire. Additionally, the examples discussed here were shown to display relevant alterations in brain signalling and had already been associated with the pathophysiology of certain neurodegenerative diseases. Lastly, we classified the heterodimers into two categories of crosstalk, positive or negative, for which there is known evidence.

Deletion of Growth Hormone Secretagogue Receptor in Kisspeptin Neurons in Female Mice Blocks Diet-Induced Obesity

The gut peptide, ghrelin, mediates energy homeostasis and reproduction by acting through its receptor, growth hormone secretagogue receptor (GHSR), expressed in hypothalamic neurons in the arcuate (ARC). We have shown 17β-estradiol (E2) increases Ghsr expression in Kisspeptin/Neurokinin B/Dynorphin (KNDy) neurons, enhancing sensitivity to ghrelin. We hypothesized that E2-induced Ghsr expression augments KNDy sensitivity in a fasting state by elevating ghrelin to disrupt energy expenditure in females. We produced a Kiss1-GHSR knockout to determine the role of GHSR in ARC KNDy neurons. We found that changes in ARC gene expression with estradiol benzoate (EB) treatment were abrogated by the deletion of GHSR and ghrelin abolished these differences. We also observed changes in metabolism and fasting glucose levels. Additionally, knockouts were resistant to body weight gain on a high fat diet (HFD). Behaviorally, we found that knockouts on HFD exhibited reduced anxiety-like behavior. Furthermore, knockouts did not refeed to the same extent as controls after a 24 h fast. Finally, in response to cold stress, knockout females had elevated metabolic parameters compared to controls. These data indicate GHSR in Kiss1 neurons modulate ARC gene expression, metabolism, glucose homeostasis, behavior, and thermoregulation, illustrating a novel mechanism for E2 and ghrelin to control Kiss1 neurons.

Effects of Short-term Fasting on Ghrelin/GH/IGF-1 Axis in Healthy Humans: The Role of Ghrelin in the Thrifty Phenotype

CONTEXT

A greater decrease in 24-hour energy expenditure (24hEE) during short-term fasting is indicative of a thrifty phenotype.

OBJECTIVE

As ghrelin and the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis are implicated in the regulation of energy intake and metabolism, we investigated whether ghrelin, GH, and IGF-1 concentrations mediate the fasting-induced decrease in 24hEE that characterizes thriftiness.

METHODS

In 47 healthy individuals, 24hEE was measured in a whole-room indirect calorimeter both during 24-hour eucaloric and fasting conditions. Plasma total ghrelin, GH, and IGF-1 concentrations were measured by enzyme-linked immunosorbent assay after an overnight fast the morning before and after each 24-hour session.

RESULTS

During 24-hour fasting, on average 24hEE decreased by 8.0% (P < .001), GH increased by ~5-fold (P < .001), whereas ghrelin (mean +23 pg/mL) and IGF-1 were unchanged (both P ≥ .19) despite a large interindividual variability in ghrelin change (SD 150 pg/mL). Greater fasting-induced increase in ghrelin was associated with a greater decrease in 24hEE during 24-hour fasting (r = -0.42, P = .003), such that individuals who increased ghrelin by 200 pg/mL showed an average decrease in 24hEE by 55 kcal/day.

CONCLUSION

Short-term fasting induced selective changes in the ghrelin/GH/IGF-1 axis, specifically a ghrelin-independent GH hypersecretion that did not translate into increased IGF-1 concentrations. Greater increase in ghrelin after 24-hour fasting was associated with greater decrease in 24hEE, indicating ghrelin as a novel biomarker of increased energy efficiency of the thrifty phenotype.

Progress on growth promoting therapies other than growth hormone

Recombinant human growth hormone is a classical therapeutic drug for children with short stature. In recent years, as the mechanism of growth in children has been further explored, growth-promoting therapies other than growth hormone have made great progress. Recombinant human insulin-like growth factor (IGF)-1 is the main treatment for primary IGF-1 deficiency, and C-type natriuretic peptide (CNP) offers a therapeutic option for children with short stature due to chondrodysplasia. Growth hormone-releasing peptide analogues stimulate growth hormone release and may be used for growth-promoting therapy. In addition, gonadotropin-releasing hormone analogue (GnRHa) and aromatase inhibitors may delay the bone age in children and may be beneficial in improving final height. In this article, the research progress of growth-promoting therapies other than growth hormones is reviewed to provide more options for the clinical treatment of children with short stature.

Multiple roles of ghrelin in breast cancer

Breast cancer is one of the most threatening malignant tumors in women worldwide; hence, investigators are continually performing novel research in this field. However, an accurate prediction of its prognosis and postoperative recovery remains difficult. The severity of breast cancer is patient-specific and affected by several health factors; thus, unknown mechanisms may affect its progression. This article analyzes existing literature on breast cancer, ranging from the discovery of ghrelin to its present use, and aims to provide a reference for future research into breast cancer mechanisms and treatment-plan improvement. Various parts of ghrelin have been associated with breast cancer by direct or indirect evidence. The ghrelin system may encompass the direction of expanding breast cancer treatment methods and prognostic indicators. Therefore, we compiled almost all studies on the relationship between the ghrelin system and breast cancer, including unacylated ghrelin, its GHRL gene, ghrelin O-acyltransferase, the receptor growth hormone secretagogue receptor, and several splice variants of ghrelin to lay the foundation for future research.

Sakarinin İştah, Enerji Alımı ve Serum Ghrelin Üzerinde Etkisi Var mı? Sağlıklı Erkeklerde Randomize, Kontrollü, Çapraz Bir Çalışma

Amaç: Günümüzde şeker yerine enerji içermeyen yapay tatlandırıcılar yaygın olarak kullanılmaktadır. Ancak bilinenin aksine yapay tatlandırıcıların metabolizmayı çeşitli yönlerden etkilediği düşünülmektedir. Bu çalışmanın amacı sakarinin serum ghrelin düzeyi, iştah ve besin tüketimi üzerindeki etkilerini değerlendirmektir. Metod: Randomize, kontrollü ve çapraz olarak yapılan çalışmaya 20-29 yaşları arasında dokuz sağlıklı erkek katılmıştır. Her katılımcıya 300 ml su, 75 gram sakaroz içeren 300 ml su ve 240 miligram sakarin içeren 300 ml su verilmiştir. Başlangıç, 30., 60., 90., 120. ve 180. dakikalarda iştahı değerlendirmek için Görsel Analog Skala uygulanmış ve ghrelin analizi için kan örnekleri alınmıştır. Yüzsekseninci sonra katılımcılar ad libitum beslenmişler ve her uygulama günün sonuna kadar 24 saatlik diyet besin tüketim kaydı tutmuşlardır. Bulgular: Altmışıncı ve 120. dakikalarda sadece su ve sakarinli içeceklerde ortalama ghrelin düzeyi sükroz içeren içeceğe kıyasla daha yüksektir (p

Appetite ratings and ghrelin concentrations in young adults after administration of a balanced meal. Does sex matter?

Background

Sex-based differences in appetite ratings have been observed previously. Ghrelin is the only known orexigenic peptide hormone. Sex differences in postprandial ghrelin responses may underlie different perceptions of hunger and satiety, but results are conflicting. We conducted a parallel study to evaluate sex differences in postprandial appetite ratings and ghrelin concentration after administration of a physiological meal among students of University of Milan.

Methods

Twenty-four healthy, normal weight volunteers (12 men and 12 women) aged 18–35 years were recruited. A balanced mixed meal meeting 40% of the estimated daily energy expenditure and providing 60% of calories from carbohydrates, 25% from lipids and 15% from protein was administrated. Sex differences in appetite ratings (satiety, hunger, fullness and desire to eat) and magnitude of ghrelin suppression during postprandial period (up to 180 min) were determined.

Results

In the fasting state, men and women did not differ in appetite ratings and ghrelin concentrations. After feeding, women tended to reach peak of satiety earlier than men, who in turn reached the nadir of hunger later than women (median: 30 min, interquartile range (IQR): 1; 120 vs. 1 min, IQR 1; 1, p = 0.007). Ghrelin suppression was greater in women (median decremental AUC − 95, IQR − 122; − 66) than in men (median decremental AUC − 47, IQR − 87; − 31, p = 0.041).

Conclusions

These findings suggest sex differences in the postprandial appetite regulation that might be important for nutritional strategy to prevent and treat obesity and eating disorders.

Ghrelin pretreatment enhanced the protective effect of bone marrow-derived mesenchymal stem cell-conditioned medium on lipopolysaccharide-induced endothelial cell injury

BACKGROUND

Lung endothelial barrier injury plays a crucial role in the pathophysiology of acute respiratory distress syndrome. It has been demonstrated that bone marrow-derived mesenchymal stem cells-conditioned medium (BMSCs-CM) and ghrelin have a protective effect. This study investigated if ghrelin pretreatment enhanced the protective effect of BMSCs-CM on lipopolysaccharide (LPS)-induced endothelial cell injury.

METHODS

BMSCs were isolated from rat bone marrow, expanded, then phenotypically tested for mesenchymal stem cell-identifying criteria by flow cytometry. The effects of the conditioned medium derived from ghrelin-pretreated BMSCs (BMSCs-^{ghrelin-pretreated}-CM) on LPS-injured endothelial cells were evaluated by migration, apoptosis, permeability, and pro-inflammatory factor (e.g., tumor necrosis factor-α, interleukin (IL)-1β, and IL-6) assays in endothelial cells. Further, AKT/GSK3β pathway activation in endothelial cells was examined by Western blot, and the gene expression profiles of ghrelin-pretreated BMSCs were examined by RNA sequencing.

RESULTS

BMSCs-^{ghrelin-pretreated}-CM had a greater protective effect on LPS-induced endothelial cell injury than BMSCs-CM by improving cell migration, alleviating apoptosis, and reducing endothelial permeability and the release of pro-inflammatory factors in endothelial cells. The mechanism is partly related to AKT/GSK3β pathway activation after BMSCs-^{ghrelin-pretreated}-CM treatment. There were five upregulated candidate genes (Wnt5a [i.e., Wnt Family Member 5A], S100b [i.e., S100 Calcium-Binding Protein B], Bmp2 [i.e., Bone Morphogenetic Protein 2], Id4 [i.e., Inhibitor Of DNA Binding 4], and PTHLH [i.e., Parathyroid Hormone Like Hormone]) in BMSCs after ghrelin treatment, and all were associated with AKT pathway activation and endothelial function.

CONCLUSIONS

Ghrelin pretreatment enhanced the protective effect of BMSCs-CM on LPS-induced endothelial cell injury, partly by activating the AKT/GSK3β pathway.

The Effect of Ghrelin on the Maturation of Sheep Oocytes and Early Embryonic Development In Vitro

Simple Summary

Different gradients of ghrelin (0, 100, 200, and 300 ng/mL) were added to the IVM system of sheep oocytes to observe their changes, and 200 ng/mL ghrelin was found to be the optimal concentration. The RNA-seq analysis showed that the Cell cycle signaling pathway was enriched. The results suggest that adding ghrelin shortens the duration of IVM of sheep oocytes and hinders early embryonic development.

Abstract

In vitro maturation (IVM) of sheep oocytes and early embryonic development are of great scientific importance for the study of reproductive development in sheep. Ghrelin is an important hormone that regulates the secretion of the growth hormone (GH). In this study, different gradients of ghrelin (0, 100, 200, and 300 ng/mL) were added to the IVM system of sheep oocytes to observe their cell morphology, and Hosesth 33342 staining was used to determine the time taken for oocytes to reach different developmental stages. We found 200 ng/mL ghrelin to be the optimal concentration. The RNA-seq analysis showed that many signaling pathways were significantly altered by ghrelin. Cell cycle, Wnt, and oxidative phosphorylation were activated; the P53 was inhibited. These pathways together regulate the maturation of oocytes and early embryonic development in vitro. The effects of the addition of ghrelin were verified by the expression of GLUT1 in early embryonic development. The results suggest that adding ghrelin shortens the duration of the IVM of sheep oocytes and hinders early embryonic development. This study provides new insights into the effects of exogenous ghrelin on sheep oocyte maturation and early embryonic development in vitro.

Molar extraction alters gastric mucosa and ghrelin expression in rat stomach: A preliminary study

Objectives:

Ghrelin is a key regulator of food intake and is considered a hunger hormone that affects cognition, memory, glucose metabolism, and antidepressant effects. Altered occlusion, such as a loss of molars, has been thought to retard digestive function. However, the association between occlusion and digestive function remains poorly understood. Here, we aimed to explore the effect of bilateral maxillary molar extraction on the gastrointestinal mucosa of growing rats and the expression of ghrelin and its receptor, growth hormone secretagogue receptor (GHSR).

Material and Methods:

Twenty-four male 5-week-old Wistar rats were divided into control (CON) and experimental (EXP) groups (n = 12/group). The rats in the EXP group underwent extraction of the bilateral maxillary first, second, and third molars under general anesthesia. Rats in the CON group underwent a sham operation. All rats in both the CON and EXP groups were fed a powder diet and water ad libitum. The body weight of all rats was monitored throughout the EXP period. Rats in both the CON and EXP groups were euthanized on days 14 and 28, and the stomachs were isolated and subjected to histological analysis. Paraffin serial sections were prepared using a microtome for hematoxylin-eosin and immunohistochemical staining using anti-ghrelin and anti-GHSR antibodies. The distribution and expression of ghrelin-immunopositive and GHSR cells were detected and observed under a light microscope. Data were statistically analyzed using t-tests (P < 0.05).

Results:

There were no significant differences in body weight between the CON and EXP groups throughout the EXP period. Histological analysis showed that the area of the submucosa (ASM), and the number of ghrelinimmunopositive cells were significantly decreased in the EXP group compared with the CON group on day 14. Alternatively, there was no significant difference in the ASM and the number of ghrelin-immunopositive cells between the CON and EXP groups on day 28, whereas the number of ghrelin receptors showed no differences across groups. Furthermore, the number of eosinophilic blood cells significantly increased in the EXP group on days 14 and 28.

Conclusion:

Our findings suggest that bilateral maxillary molar extraction may trigger stomach mucosal changes and alter digestive function through ghrelin expression in rats. This is the first report that occlusal deficiency could alter ghrelin expression in the mucosa of the rat stomach, thus raising concerns about the consequential role of ghrelin.

LEAP2: Next game-changer of pharmacotherapy for overweight and obesity?

The world is seeking effective and safe weight-lowering drugs for centuries. LEAP2, acting on ghrelin and growth hormone secretagogue receptor, according to a study by Hageman et al.¹ in this issue of Cell Reports Medicine, found its way toward the next target of pharmacotherapy for obesity and related diseases.

Ghrelin and Cancer: Examining the Roles of the Ghrelin Axis in Tumor Growth and Progression

Ghrelin, a hormone produced and secreted from the stomach, is prim arily known as an appetite stimulant. Recently, it has emerged as a potential regulator/biomarker of cancer progression. Inconsistent results on this subject make this body of literature difficult to interpret. Here, we attempt to identify commonalities in the relationships between ghrelin and various cancers, and summarize important considerations for future research. The main players in the ghrelin family axis are unacylated ghrelin (UAG), acylated ghrelin (AG), the enzyme ghrelin O-acyltransferase (GOAT), and the growth hormone secretagogue receptor (GHSR). GOAT is responsible for the acylation of ghrelin, after which ghrelin can bind to the functional ghrelin receptor GHSR-1a to initiate the activation cascade. Splice variants of ghrelin also exist, with the most prominent being In1-ghrelin. In this review, we focus primarily on the potential of In1-ghrelin as a biomarker for cancer progression, the unique characteristics of UAG and AG, the importance of the two known receptor variants GHSR-1a and 1b, as well as the possible mechanisms through which the ghrelin axis acts. Further understanding of the role of the ghrelin axis in tumor cell proliferation could lead to the development of novel therapeutic approaches for various cancers.

Mechanistic Investigation of GHS-R Mediated Glucose-Stimulated Insulin Secretion in Pancreatic Islets

Ghrelin receptor, a growth hormone secretagogue receptor (GHS-R), is expressed in the pancreas. Emerging evidence indicates that GHS-R is involved in the regulation of glucose-stimulated insulin secretion (GSIS), but the mechanism by which GHS-R regulates GSIS in the pancreas is unclear. In this study, we investigated the role of GHS-R on GSIS in detail using global Ghsr^−/− mice (in vivo) and Ghsr-ablated pancreatic islets (ex vivo). GSIS was attenuated in both Ghsr^−/− mice and Ghsr-ablated islets, while the islet morphology was similar between WT and Ghsr^−/− mice. To elucidate the mechanism underpinning Ghsr-mediated GSIS, we investigated the key steps of the GSIS signaling cascade. The gene expression of glucose transporter 2 (Glut2) and the glucose-metabolic intermediate—glucose-6-phosphate (G6P) were reduced in Ghsr-ablated islets, supporting decreased glucose uptake. There was no difference in mitochondrial DNA content in the islets of WT and Ghsr^−/− mice, but the ATP/ADP ratio in Ghsr^−/− islets was significantly lower than that of WT islets. Moreover, the expression of pancreatic and duodenal homeobox 1 (Pdx1), as well as insulin signaling genes of insulin receptor (IR) and insulin receptor substrates 1 and 2 (IRS1/IRS2), was downregulated in Ghsr^−/− islets. Akt is the key mediator of the insulin signaling cascade. Concurrently, Akt phosphorylation was reduced in the pancreas of Ghsr^−/− mice under both insulin-stimulated and homeostatic conditions. These findings demonstrate that GHS-R ablation affects key components of the insulin signaling pathway in the pancreas, suggesting the existence of a cross-talk between GHS-R and the insulin signaling pathway in pancreatic islets, and GHS-R likely regulates GSIS via the Akt-Pdx1-GLUT2 pathway.

Citrus Extract as a Perspective for the Control of Dyslipidemia: A Systematic Review With Meta-Analysis From Animal Models to Human Studies

This study aims to obtain scientific evidence on the use of Citrus to control dyslipidemia. The surveys were carried out in 2020 and updated in March 2021, in the PubMed, Scopus, LILACS, and SciELO databases, using the following descriptors: Citrus, dyslipidemias, hypercholesterolemia, hyperlipidemias, lipoproteins, and cholesterol. The risk of bias was assessed according to the Cochrane methodology for clinical trials and ARRIVE for preclinical trials. A meta-analysis was performed using the application of R software. A total of 958 articles were identified and 26 studies demonstrating the effectiveness of the Citrus genus in controlling dyslipidemia were selected, of which 25 were included in the meta-analysis. The effects of Citrus products on dyslipidemia appear consistently robust, acting to reduce total cholesterol, LDL, and triglycerides, in addition to increasing HDL. These effects are associated with the composition of the extracts, extremely rich in antioxidant, as flavonoids, and that act on biochemical targets involved in lipogenesis and beta-oxidation. The risk of bias over all of the included studies was considered critically low to moderate. The meta-analysis demonstrated results favorable to control dyslipidemia by Citrus products. On the other hand, high heterogeneity values were identified, weakening the evidence presented. From this study, one can suggest that Citrus species extracts are potential candidates for dyslipidemia control, but more studies are needed to increase the strength of this occurrence.

Novel Role of Ghrelin Receptor in Gut Dysbiosis and Experimental Colitis in Aging

Chronic low-grade inflammation is a hallmark of aging, which is now coined as inflamm-aging. Inflamm-aging contributes to many age-associated diseases such as obesity, type 2 diabetes, cardiovascular disease, and inflammatory bowel disease (IBD). We have shown that gut hormone ghrelin, via its receptor growth hormone secretagogue receptor (GHS-R), regulates energy metabolism and inflammation in aging. Emerging evidence suggests that gut microbiome has a critical role in intestinal immunity of the host. To determine whether microbiome is an integral driving force of GHS-R mediated immune-metabolic homeostasis in aging, we assessed the gut microbiome profiles of young and old GHS-R global knockout (KO) mice. While young GHS-R KO mice showed marginal changes in Bacteroidetes and Firmicutes, aged GHS-R KO mice exhibited reduced Bacteroidetes and increased Firmicutes, featuring a disease-susceptible microbiome profile. To further study the role of GHS-R in intestinal inflammation in aging, we induced acute colitis in young and aged GHS-R KO mice using dextran sulfate sodium (DSS). The GHS-R KO mice showed more severe disease activity scores, higher proinflammatory cytokine expression, and decreased expression of tight junction markers. These results suggest that GHS-R plays an important role in microbiome homeostasis and gut inflammation during aging; GHS-R suppression exacerbates intestinal inflammation in aging and increases vulnerability to colitis. Collectively, our finding reveals for the first time that GHS-R is an important regulator of intestinal health in aging; targeting GHS-R may present a novel therapeutic strategy for prevention/treatment of aging leaky gut and inflammatory bowel disease.

Effect of ghrelin on hypoxia-related cardiac angiogenesis: involvement of miR-210 signalling pathway

OBJECTIVE

Hypoxia is the main stimulus for angiogenesis. Hypoxia-inducible factor (HIF)-1α, vascular endothelial growth factor (VEGF), and miR-210 are involved in the hypoxia-induced angiogenesis. This study examined the effects of hypoxia and/or ghrelin on miR-210, HIF-1α, and VEGF levels in the heart of rats.

METHODS

Wistar rats were randomly divided into 4 groups (n = 6): control; ghrelin, received daily intraperitoneal injections of ghrelin; hypoxia, was exposed to hypoxic condition; hypoxia + ghrelin, was exposed to hypoxic condition and received intraperitoneal injections of ghrelin, for 2 weeks. Myocardial angiogenesis, the expression level of miR-210, and protein levels of HIF-1α and VEGF were assayed in the heart samples.

RESULTS

Hypoxia increased myocardial angiogenesis and cardiac levels of miR-210, HIF-1α, and VEGF. However, ghrelin inhibited these hypoxia-induced changes. Interestingly, ghrelin had no significant effect on miR-210, HIF-1α, and VEGF levels in normoxic condition.

CONCLUSION

Ghrelin may be useful as an anti-angiogenic factor.

EFFECT OF 20-HOUR FASTING AND LOW FAT DIET ON GHRELIN HORMONE, GLUCOSE LEVEL AND LIVER FUNCTION IN ALBINO RATS MALE

OBJECTIVE

The aim: It aims to study the effect of fasting and low fat diet on ghrelin hormone, glucose level, the liver enzymes AST and ALT.

PATIENTS AND METHODS

Materials and methods: The experimental study was conducted using 24 healthy young male albino rat weighing 95±5 gram and age 2 month, one-way (ANOVA) were employed to determine a significance of differences.

RESULTS

Results: A significant increase p≤0.05 in glucose level of non-fasting control group compere with non-fasting low fat diet group, significant increase p≤0.05 in glucose level of control group fasting for 20h compared with low fat diet fasting for 20h group, significant decrease p≤0.05 when compares non-fasting low fat diet compares to 20h fasting low fat diet and significant decrease p≤0.05 when compares non-fasting control compares to 20h fasting control, while the effect of fasting and low fat diet on ghrelin hormone. A significant decrease p≤0.05 in ghrelin hormone level of non-fasting control group compere with non-fasting low fat diet group, significant increase p≤0.05 in ghrelin hormone of control group fasting for 20h compared with low fat diet fasting for 20h group, non-fasting control compares to 20h fasting control show a significant (p≤0.05) increase, Fasting with low fat diet cause a significant decrease p≤0.05 in ALT level, also in AST level there was a significant decrease p≤0.05 after 20h fasting.

CONCLUSION

Conclusions: The fasting and low fat diet have effected on ghrelin hormone, glucose level and fasting with low fat diet cause decrease in ALT level, also in AST level decrease after 20h fasting in male albino rats.

Exocrine-Endocrine Crosstalk: The Influence of Pancreatic Cellular Communications on Organ Growth, Function and Disease

Diabetes mellitus, a disease that affects nearly 536.6 million people worldwide, is characterized by the death or dysfunction of insulin-producing beta cells of the pancreas. The beta cells are found within the islets of Langerhans, which are composed of multiple hormone-producing endocrine cells including the alpha (glucagon), delta (somatostatin), PP (pancreatic polypeptide), and epsilon (ghrelin) cells. There is direct evidence that physical and paracrine interactions between the cells in the islet facilitate and support beta cell function. However, communication between endocrine and exocrine cells in the pancreas may also directly impact beta cell growth and function. Herein we review literature that contributes to the view that "crosstalk" between neighboring cells within the pancreas influences beta cell growth and function and the maintenance of beta cell health.

Serum levels of hormones regulating appetite in patients with cystic fibrosis - a single-center, cross-sectional study

Cystic fibrosis (CF), which is the most common inherited genetically determined disease caused by a mutation in the gene for the CF transmembrane conductance regulator protein. Pulmonary failure is the leading cause of death in this population, while the dysregulation of endocrine system creates significant disorders, including malnutrition, underweight, and CF-related diabetes. Therefore, the objective of our study was to determine the following hormones in the serum of patients with CF: ghrelin, putative peptide YY (PYY), Agouti-signaling protein (ASP), and alpha-melanocyte-stimulating hormone (α-MSH). To our knowledge, serum levels of PYY, ASP, and α-MSH have not yet been assessed in CF. For this purpose, we measured hormone levels using enzyme-linked immunosorbent assays in 38 patients from the local CF care center, as well as 16 sex- and age-matched healthy controls. Moreover, we estimated the correlations between the tested hormones and the parameters of the patients' clinical status. In this study, we found sinificantly reduced serum levels of ghrelin and ASP in patients with CF (p<0.01). There was no difference in PYY and α-MSH levels between participants with CF and healthy subjects. Furthermore, there was no difference in hormone levels between females and males with CF. The type of gene mutation (homozygous or heterozygous for ΔF508) had no effect on hormone levels. Ghrelin was negatively correlated with age, body mass index, and C-reactive protein. PYY was negatively associated with the age of the patients. Hormone dysregulation in CF may contribute to decreased appetite, as well as many other disturbed processes. Therefore, ghrelin appears to play a key role in the regulation of energy management of CF. Future multicenter and multidisciplinary studies should focus on an unequivocal understanding of the role of these hormones in CF.

Ghrelin and Cannabinoid Functional Interactions Mediated by Ghrelin/CB1 Receptor Heteromers That Are Upregulated in the Striatum From Offspring of Mice Under a High-Fat Diet

There is evidence of ghrelinergic-cannabinoidergic interactions in the central nervous system (CNS) that may impact on the plasticity of reward circuits. The aim of this article was to look for molecular and/or functional interactions between cannabinoid CB₁ and ghrelin GHS-R1a receptors. In a heterologous system and using the bioluminescence resonance energy transfer technique we show that human versions of cannabinoid CB₁ and ghrelin GHS-R1a receptors may form macromolecular complexes. Such receptor heteromers have particular properties in terms of CB₁/G_i-mediated signaling and in terms of GHS-R1a-G_q-mediated signaling. On the one hand, just co-expression of CB₁R and GHS-R1a led to impairment of cannabinoid signaling. On the other hand, cannabinoids led to an increase in ghrelin-derived calcium mobilization that was stronger at low concentrations of the CB₁ receptor agonist, arachidonyl-2’-chloroethylamide (ACEA). The expression of CB₁-GHS-R1a receptor complexes in striatal neurons was confirmed by in situ proximity ligation imaging assays. Upregulation of CB₁-GHS-R1a- receptor complexes was found in striatal neurons from siblings of pregnant female mice on a high-fat diet. Surprisingly, the expression was upregulated after treatment of neurons with ghrelin (200 nM) or with ACEA (100 nM). These results help to better understand the complexities underlying the functional interactions of neuromodulators in the reward areas of the brain.

Differential Influence of Pueraria lobata Root Extract and Its Main Isoflavones on Ghrelin Levels in Alcohol-Treated Rats

The study was carried out on alcohol-preferring male Wistar rats. The following drugs were repeatedly (28×) administered: acamprosate (500 mg/kg, p.o.), naltrexone (0.1 mg/kg, i.p), and Pueraria lobata (kudzu) root extract (KU) (500 mg/kg, p.o.) and its isoflavones: daidzin (40 mg/kg, p.o.) and puerarin (150 mg/kg, p.o.). Their effects on a voluntary alcohol intake were assessed. KU and alcohol were also given for 9 days in an experiment on alcohol tolerance development. Finally, total and active ghrelin levels in peripheral blood serum were measured by ELISA method. Acamprosate, naltrexone, daidzin, and puerarin, reducing the alcohol intake, caused an increase in both forms of ghrelin levels. On the contrary, though KU inhibited the alcohol intake and alcohol tolerance development, it reduced ghrelin levels in alcohol-preferring rats. The changes of ghrelin concentration could play a role as an indicator of the currently used drugs. The other effect on the KU-induced shift in ghrelin levels in the presence of alcohol requires further detailed study.

Parkinson's Disease and the Gut: Symptoms, Nutrition, and Microbiota

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide, characterized by symptoms of bradykinesia, rigidity, postural instability, and tremor. Recently, there has been a growing focus on the relationship between the gut and the development of PD. Emerging to the forefront, an interesting concept has developed suggesting that the initial pathophysiological changes occur in the gastrointestinal tract before changes are seen within the brain. This review is aimed at highlighting the relationship between PD and the gastrointestinal tract, along with the supporting evidence for this. Firstly, we will focus on the gastrointestinal conditions and symptoms which commonly affects patients, including both upper and lower gastrointestinal issues. Secondly, the impact of nutrition and diet on neurological health and PD physiology, with particular emphasis on commonly consumed items including macronutrients and micronutrients. Finally, variability of the gut microbiome will also be discussed and its link with both the symptoms and signs of PD. The evidence presented in this review highly suggests that the initial pathogenesis in the gut may proceed the development of prodromal PD subtypes, and therefore building on this further could be imperative and lead to earlier diagnosis with new and improved therapeutics.

The low-carbohydrate-diet score is associated with resting metabolic rate: an epidemiologic study among Iranian adults

Purpose

Low-carbohydrate diet (LCD) has been used for weight loss and preventing obesity, but the association of adherence to LCD and resting metabolic rate (RMR) has not been investigated. This study aimed to investigate the association between the low-carbohydrate-diet score (LCDS) and RMR among Iranian adults.

Methods

This cross-sectional study was conducted on 270 Iranian adults 18-70 y of age. To assess dietary intakes, participants completed a validated food frequency questionnaire. The LCDS was calculated based on carbohydrate, protein and fat intake, expressed as a percentage of energy. The higher score indicates the lower carbohydrate and the higher protein and fat intake. RMR was measured by indirect calorimetry after an overnight fast.

Results

Multivariate-adjusted means showed that RMR significantly increased across tertiles (p = 0.041). However, there were no significant differences in the mean of fat mass (FM) and fat-free mass (FFM) across tertiles of LCDS (p = 0.986 and p = 0.621, respectively). Also LCDS and RMR (r = 0.14, p = 0.021) were found to be correlated, but LCDS and FFM (r = 0.06, p = 0.323), FM (r = -0.05, p = 0.412), had no statistically significant correlation. RMR had a significant positive association with LCDs in the crude model (β = 18.81, 95% CI: 2.55, 35.07, P = 0.024). Moreover, after controlling for covariates this association changed to non-significant (β = -0.14, 95% CI: -7.05, 19.25, P = 0.03).

Conclusion

Adherence to diets lower in carbohydrates and higher in fat and protein were associated with higher RMR. Further studies with a larger sample size are needed to confirm these findings.

Decreased plasma ghrelin in male ALS patients is associated with poor prognosis

Physiological changes including altered nutritional status influence disease progression and survival in patients with amyotrophic lateral sclerosis (ALS). Ghrelin affects the nutritional status by regulating appetite and energy expenditure, and also has neuroprotective effects. To investigate the association between ghrelin and ALS prognosis, we analyzed plasma acylated-ghrelin levels in 33 patients with ALS. Compared among ALS patients, male had lower plasma ghrelin levels than female, although disease specificity is unknown. ALS patients, especially male ALS patients, with low plasma ghrelin levels (<15 fmol/mL) had significantly shorter post-examination survival times than those with high plasma ghrelin levels (≥15 fmol/mL). Univariate and multivariate analyses revealed a significant effect of ghrelin levels on post-examination survival. Immunohistochemical study of autopsied stomach samples from 8 of 33 patients revealed that the population of ghrelin-positive cells tended to be reduced in the low-plasma ghrelin group than in the high-plasma ghrelin group. Our findings suggest that ghrelin levels are an independent predictor of survival in ALS, especially male ALS patients, and the ghrelin-positive cells may decrease in ALS with low plasma ghrelin. Thus, reduced ghrelin secretion may be associated with poor prognosis among patients with ALS.

Walking down Skeletal Muscle Lane: From Inflammasome to Disease

Over the last decade, innate immune system receptors and sensors called inflammasomes have been identified to play key pathological roles in the development and progression of numerous diseases. Among them, the nucleotide-binding oligomerization domain (NOD-), leucine-rich repeat (LRR-) and pyrin domain-containing protein 3 (NLRP3) inflammasome is probably the best characterized. To date, NLRP3 has been extensively studied in the heart, where its effects and actions have been broadly documented in numerous cardiovascular diseases. However, little is still known about NLRP3 implications in muscle disorders affecting non-cardiac muscles. In this review, we summarize and present the current knowledge regarding the function of NLRP3 in diseased skeletal muscle, and discuss the potential therapeutic options targeting the NLRP3 inflammasome in muscle disorders.

Clinical and biomarker assessment of frailty in liver transplantation

PURPOSE OF REVIEW

Liver cirrhosis results in progressive decline, or frailty, which leads to poor outcomes and decreased survival. Multiple biomarkers and clinical assessment tools for quantifying frailty in liver transplant candidates exist, but a universal scoring protocol is lacking. Criteria vary between studies and correlation with patient outcome is not always clear. This review aims to summarize the pertinent biomarkers and assessment tools of frailty in cirrhosis.

RECENT FINDINGS

As cirrhosis progresses, the resultant 'frailty' is an inseparable independent predictor of pre and posttransplant mortality. Pro-inflammatory, neuroendocrine, and adipokine factors are dysregulated - leading to paradoxical anorexia and downregulation of orexigenic signals. The resulting catabolic utilization of amino and fatty acids leads to progressive malnutrition and sarcopenia. Both functional and imaging criteria define sarcopenia in cirrhotic patients, and degree of debilitation correlates with mortality. Liver-disease-specific frailty biomarkers and scoring tools are optimal to assess physical dysfunction in cirrhotics to promote early diagnosis and intervention.

SUMMARY

Liver cirrhosis and resulting frailty are progressive and portend a poor patient prognosis. A comprehensive, validated algorithm for detecting and quantifying frailty specific to liver disease would allow for standardization and facile application in the clinical setting. Early diagnosis is key for timely intervention and improved patient outcomes.

The role of endocrine hormones in the pathogenesis of adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is a common spinal deformity characterized by changes in the three-dimensional structure of the spine. It usually initiates during puberty, the peak period of human growth when the secretion of numerous hormones is changing, and it is more common in females than in males. Accumulating evidence shows that the abnormal levels of many hormones including estrogen, melatonin, growth hormone, leptin, adiponectin and ghrelin, may be related to the occurrence and development of AIS. The purpose of this review is to provide a summary and critique of the research published on each hormone over the past 20 years, and to highlight areas for future study. It is hoped that the presentation will help provide a better understanding of the role of endocrine hormones in the pathogenesis of AIS.

Identification of the Ghrelin and Cannabinoid CB2 Receptor Heteromer Functionality and Marked Upregulation in Striatal Neurons from Offspring of Mice under a High-Fat Diet

Cannabinoids have been reported as orexigenic, i.e., as promoting food intake that, among others, is controlled by the so-called “hunger” hormone, ghrelin. The aim of this paper was to look for functional and/or molecular interactions between ghrelin GHSR1a and cannabinoid CB₂ receptors at the central nervous system (CNS) level. In a heterologous system we identified CB₂-GHSR1a receptor complexes with a particular heteromer print consisting of impairment of CB₂ receptor/G_i-mediated signaling. The blockade was due to allosteric interactions within the heteromeric complex as it was reverted by antagonists of the GHSR1a receptor. Cannabinoids acting on the CB₂ receptor did not affect cytosolic increases of calcium ions induced by ghrelin acting on the GHSR1a receptor. In situ proximity ligation imaging assays confirmed the expression of CB₂-GHSR1a receptor complexes in both heterologous cells and primary striatal neurons. We tested heteromer expression in neurons from offspring of high-fat-diet mouse mothers as they have more risk to be obese. Interestingly, there was a marked upregulation of those complexes in striatal neurons from siblings of pregnant female mice under a high-fat diet.

Is ghrelin a biomarker of early-onset scoliosis in children with Prader-Willi syndrome?

Background

Adolescents with idiopathic scoliosis display high ghrelin levels. As hyperghrelinemia is found in patients with PWS and early-onset scoliosis (EOS) is highly prevalent in these patients, our aims were to explore (1) whether ghrelin levels differ between those with and without EOS and correlate with scoliosis severity, and (2) whether ghrelin levels in the first year of life are associated with the later development of EOS.

Methods

We used a case control study design for the first question and a longitudinal design for the second. Patients with PWS having plasma ghrelin measurements recorded between 2013 and 2018 in our database were selected and 30 children < 10 years old with EOS and 30 age- and BMI-matched controls without EOS were included. The Cobb angle at diagnosis was recorded. In addition, 37 infants with a ghrelin measurement in the first year of life were followed until 4 years of age and assessed for EOS. Total ghrelin (TG), acylated (AG) and unacylated ghrelin (UAG), and the AG/UAG ratio were analyzed.

Results

EOS children had an AG/UAG ratio statistically significantly lower than controls. The Cobb angle was positively correlated with TG and UAG. TG and AG in the first year of life were higher in infants who later develop EOS without reaching a statistically significant difference.

Conclusions

Our results suggest that ghrelin may play a role in the pathophysiology of EOS in PWS. Higher ghrelinemia in the first year of life required careful follow-up for EOS.

Influence of innate immune activation on endocrine and metabolic pathways in infancy

Prematurity is the leading cause of neonatal morbidity and mortality worldwide. Premature infants often require extended hospital stays, with increased risk of developing infection compared with term infants. A picture is emerging of wide-ranging deleterious consequences resulting from innate immune system activation in the newborn infant. Those who survive infection have been exposed to a stimulus that can impose long-lasting alterations into later life. In this review, we discuss sepsis-driven alterations in integrated neuroendocrine and metabolic pathways and highlight current knowledge gaps in respect of neonatal sepsis. We review established biomarkers for sepsis and extend the discussion to examine emerging findings from human and animal models of neonatal sepsis that propose novel biomarkers for early identification of sepsis. Future research in this area is required to establish a greater understanding of the distinct neonatal signature of early and late-stage infection, to improve diagnosis, curtail inappropriate antibiotic use, and promote precision medicine through a biomarker-guided empirical and adjunctive treatment approach for neonatal sepsis. There is an unmet clinical need to decrease sepsis-induced morbidity in neonates, to limit and prevent adverse consequences in later life and decrease mortality.

Role of appetite hormone dysregulation in the cognitive function among patients with bipolar disorder and major depressive disorder

OBJECTIVES

The association of appetite hormones with cognitive function in patients with affective disorders remains unknown.

METHODS

All total, 58 adult patients with bipolar I disorder, 36 with bipolar II disorder, 40 with major depressive disorder were enrolled and age and sex-matched with 40 controls. The levels of appetite hormones leptin, ghrelin, insulin and adiponectin were assessed. Wisconsin Card Sorting Test was used to assess executive function.

RESULTS

A general linear model, adjusted for demographic data and clinical symptoms, demonstrated the ghrelin levels were higher in patients with bipolar I or II disorder than in those with major depressive disorder and controls (p < 0.001). We also identified a positive correlation of ghrelin level and executive function among patients with bipolar I (p = 0.033) and II (p = 0.027) disorders, but not among those with major depressive disorder and controls.

CONCLUSIONS

Patients with bipolar I or II disorder were more likely to have high levels of ghrelin than patients with major depressive disorder and controls, which may have a positive correlation on the cognitive function of patients with bipolar I or II disorder.

How we decide what to eat: Toward an interdisciplinary model of gut-brain interactions

Everyday dietary decisions have important short‐term and long‐term consequences for health and well‐being. How do we decide what to eat, and what physiological and neurobiological systems are involved in those decisions? Here, we integrate findings from thus‐far separate literatures: (a) the cognitive neuroscience of dietary decision‐making, and (b) growing evidence of gut–brain interactions and especially influences of the gut microbiome on diet and health outcomes. We review findings that suggest that dietary decisions and food consumption influence nutrient sensing, homeostatic signaling in the gut, and the composition of the gut microbiome. In turn, the microbiome can influence host health and behavior. Through reward signaling pathways, the microbiome could potentially affect food and drink decisions. Such bidirectional links between gut microbiome and the brain systems underlying dietary decision‐making may lead to self‐reinforcing feedback loops that determine long‐term dietary patterns, body mass, and health outcomes.

This article is categorized under:

Economics > Individual Decision‐Making

Psychology > Brain Function and Dysfunction

Psychology > Reasoning and Decision Making

Food addiction and psychiatric comorbidities: a review of current evidence

BACKGROUND

Food addiction (FA) is characterised by the consumption of appetible foods and by addictive psychological and behavioural symptoms such as cravings, tolerance, limited control of substance intake and withdrawal symptoms. Despite previous research on FA has been hindered by the lack of a formal definition for this condition, recent global trends have stirred the interest of the scientific community towards a proper classification and construct of FA. More specifically, recent studies have pointed towards shared defective neurobiological mechanisms as well as frequent comorbidities between FA, eating disorders, mood disorders, anxiety disorders and substance-related and addictive disorders.

OBJECTIVE

In this review, we will provide an overview of the complex symptomatology of food addiction evaluating its relationship with mood disorders, anxiety disorders, eating disorders and substance-related and addictive disorders.

METHODS

We wrote a systematic review and followed a PRISMA methods.

RESULTS

Patients with FA and substance use disorders show similar risk factors, neurobiological and hormonal correlates, personality traits and symptom profiles. The presence of FA appears to be directly proportional to the burden of symptoms of affective disorder. The comorbidity between FA and other eating disorders is associated with worse clinical conditions and symptoms.

CONCLUSION

FA should be considered a sort of transnosological construct existing in different psychopathological domains that have similarities with substance-related, affective, and eating disorders. Furthermore, FA seems to be likely an important factor related to several psychopathological dimensions, but further studies are needed to clarify this view.

LEVEL OF EVIDENCE

Level V, review article.

A Case Control Study on Serum Levels of Potential Biomarkers in Male Breast Cancer Patients

The global incidence of breast cancer among men is steadily growing. Despite this, compared to female breast cancer patients, there are very few studies on biomarkers in male breast cancer patients. A cross-sectional case control study was carried out to determine the serum levels of melatonin, ghrelin, dopamine, serotonin, epinephrine, and GABA in male breast cancer. All the recruited patients were obese, old, and had recently been diagnosed with the disease. They had not received any treatment for the cancer until the time of the study. Melatonin and epinephrine serum levels were significantly higher in breast cancer patients compared to their age-matched controls, whereas ghrelin, dopamine, GABA, and serotonin serum levels were lower in patients compared to the control group. The serum levels of most of the studied biomarkers in male breast cancer patients were similar to those observed in female breast cancer patients, except for serum melatonin levels.

Comorbidity burden may explain adiponectin's paradox as a marker of increased mortality risk in hemodialysis patients

Despite experimental evidence of beneficial metabolic, antiatherosclerotic and antiinflammatory effects of the 30 kDa adipokine, adiponectin, maintenance hemodialysis (MHD) patients with high adiponectin blood levels have paradoxically high mortality rates. We aimed to examine the direction of the associations between adiponectin and all-cause and cardiovascular mortality as well as with markers of oxidative stress, inflammation and nutrition in MHD patients with varying degrees of comorbidities. A cohort of 261 MHD patients (mean age 68.6 ± 13.6 years, 38.7% women), grouped according to baseline comorbidity index (CI) and serum adiponectin levels, were followed prospectively for six years. High and low concentrations were established according to median CI and adiponectin levels and cross-classified. Across the four CI-adiponectin categories, the group with low comorbidities and high adiponectin exhibited the best outcomes. Conversely, the high comorbidity group with high adiponectin levels had the lowest survival rate in both all-cause mortality (log rankχ² = 23.74, p < 0.001) and cardiovascular mortality (log rankχ² = 34.16, p < 0.001). Further data adjustment for case-mix covariates including fat mass index did not substantially affect these results. In conclusion, the direction of adiponectin’s prognostic associations in MHD patients is inverse in those with few comorbidities and direct in those with many comorbidities.

Gut peptides and the microbiome: focus on ghrelin

PURPOSE OF REVIEW

In this review, we present recent insights into the role of the gut microbiota on gastrointestinal (GI) peptide secretion and signalling, with a focus on the orexigenic hormone, ghrelin.

RECENT FINDINGS

Evidence is accumulating suggesting that secretion of GI peptides is modulated by commensal bacteria present in our GI tract. Recent data shows that the gut microbiome impacts on ghrelinergic signalling through its metabolites, at the level of the ghrelin receptor (growth hormone secretagogue receptor) and highlights concomitant changes in circulating ghrelin levels with specific gut microbiota changes. However, the mechanisms by which the gut microbiota interacts with gut peptide secretion and signalling, including ghrelin, are still largely unknown.

SUMMARY

The gut microbiota may directly or indirectly influence secretion of the orexigenic hormone, ghrelin, similar to the modulation of satiety inducing GI hormones. Although data demonstrating a role of the microbiota on ghrelinergic signalling is starting to emerge, future mechanistic studies are needed to understand the full impact of the microbiota-ghrelin axis on metabolism and central-regulated homeostatic and non-homeostatic controls of food intake.

Nausea and Vomiting in 2021: A Comprehensive Update

GOAL

A comprehensive review of treatments for nausea and vomiting (N/V).

BACKGROUND

N/V are common symptoms encountered in medicine. While most cases of acute N/V related to a specific cause can be straightforward to manage, other cases of acute N/V such as chemotherapy-induced N/V and especially chronic unexplained N/V can be difficult to control, leading to a significant decline in the patient's quality of life and increased cost of medical care from repeated hospitalizations.

STUDY

Traditional management has relied on pharmacotherapy which may be inadequate in a certain proportion of these patients. Many of the medications used in the management of N/V have significant side effect profiles making the need for new and improved interventions of great importance.

RESULTS

This review covers a broad review of the pathophysiology of N/V, pharmacotherapy, including safety concerns and controversies with established pharmaceuticals, newer immunotherapies, bioelectrical neuromodulation (including gastric electrical stimulation), behavioral and surgical therapies, and complementary medicine.

CONCLUSION

On the basis of emerging understandings of the pathophysiology of N/V, improved therapies are becoming available.

The Neural Network of Neuropeptide S (NPS): Implications in Food Intake and Gastrointestinal Functions

The Neuropeptide S (NPS), a 20 amino acids peptide, is recognized as the endogenous ligand of a previously orphan G protein-coupled receptor, now termed NPS receptor (NPSR). The limited distribution of the NPS-expressing neurons in few regions of the brainstem is in contrast with the extensive expression of NPSR in the rodent central nervous system, suggesting the involvement of this receptor in several brain functions. In particular, NPS promotes locomotor activity, behavioral arousal, wakefulness, and unexpectedly, at the same time, it exerts anxiolytic-like properties. Intriguingly, the NPS system is implicated in the rewarding properties of drugs of abuse and in the regulation of food intake. Here, we focus on the anorexigenic effect of NPS, centrally injected in different brain areas, in both sated and fasted animals, fed with standard or palatable food, and, in addition, on its influence in the gastrointestinal tract. Further investigations, regarding the role of the NPS/NPSR system and its potential interaction with other neurotransmitters could be useful to understand the mechanisms underlying its action and to develop novel pharmacological tools for the treatment of aberrant feeding patterns and obesity.

Planned morning aerobic exercise in a fasted state increases energy intake in the preceding 24 h

Purpose

We previously observed increased energy intake (EI) at the meal before planned afternoon exercise, but the proximity of the meal to exercise might have reduced the scale of the pre-exercise anticipatory eating. Therefore, this study examined EI in the 24 h before fasted morning exercise.

Methods

Fourteen males, experienced with gym-based aerobic exercise (age 25 ± 5 years, BMI 23.8 ± 2.5 kg/m²), completed counterbalanced exercise (EX) and resting (REST) trials. On day 1, subjects were told the following morning’s activity (EX/REST), before eating ad-libitum laboratory-based breakfast and lunch meals and a home-based afternoon/evening food pack. The following morning, subjects completed 30-min cycling and 30-min running (EX; 3274 ± 278 kJ) or 60-min supine rest (REST; 311 ± 34 kJ) fasted. Appetite was measured periodically, and EI quantified.

Results

Afternoon/evening EI (EX 7371 ± 2176 kJ; REST 6437 ± 2070 kJ; P = 0.017) and total 24-h EI (EX 14,055 ± 3672 kJ; REST 12,718 ± 3379 kJ; P = 0.011) were greater during EX, with no difference between trials at breakfast (P = 0.761) or lunch (P = 0.071). Relative EI (EI minus energy expended through EX/REST) was lower in EX (EX 10,781 ± 3539 kJ; REST 12,407 ± 3385 kJ; P = 0.004).

Conclusion

This study suggests planned fasted aerobic exercise increases EI during the preceding afternoon/evening, precipitating a ~ 10% increase in EI in the preceding 24-h. However, this increase did not fully compensate for energy expended during exercise; meaning exercise induced an acute negative energy balance.

Neuroendocrine Response to Exogenous Ghrelin Administration, Combined With Alcohol, in Heavy-Drinking Individuals: Findings From a Randomized, Double-Blind, Placebo-Controlled Human Laboratory Study

BACKGROUND

Accumulating evidence has established a role for the orexigenic hormone ghrelin in alcohol-seeking behaviors. Accordingly, the ghrelin system may represent a potential pharmacotherapeutic target for alcohol use disorder. Ghrelin modulates several neuroendocrine pathways, such as appetitive, metabolic, and stress-related hormones, which are particularly relevant in the context of alcohol use. The goal of the present study was to provide a comprehensive assessment of neuroendocrine response to exogenous ghrelin administration, combined with alcohol, in heavy-drinking individuals.

METHODS

This was a randomized, crossover, double-blind, placebo-controlled human laboratory study, which included 2 experimental alcohol administration paradigms: i.v. alcohol self-administration and i.v. alcohol clamp. Each paradigm consisted of 2 counterbalanced sessions of i.v. ghrelin or placebo administration. Repeated blood samples were collected during each session, and peripheral concentrations of the following hormones were measured: leptin, glucagon-like peptide-1, pancreatic polypeptide, gastric inhibitory peptide, insulin, insulin-like growth factor-1, cortisol, prolactin, and aldosterone.

RESULTS

Despite some statistical differences, findings were consistent across the 2 alcohol administration paradigms: i.v. ghrelin, compared to placebo, increased blood concentrations of glucagon-like peptide-1, pancreatic polypeptide, cortisol, and prolactin, both acutely and during the whole session. Lower levels of leptin and higher levels of aldosterone were also found during the ghrelin vs placebo session.

CONCLUSION

These findings, gathered from a clinically relevant sample of heavy-drinking individuals with alcohol use disorder, provide a deeper insight into the complex interplay between ghrelin and appetitive, metabolic, and stress-related neuroendocrine pathways in the context of alcohol use.