Biological, physiological, pathophysiological, and pharmacological aspects of ghrelin

Generation of a mouse model of thyroid storm and preliminary investigation of the therapeutic effects of ghrelin

BACKGROUND

Thyroid storm (TS), a life-threatening condition that can damage multiple organs, has limited therapeutic options. Hypercytokinemia is a suggested background, but the pathological condition is unclear and there are no appropriate animal models. We aimed to develop a TS mouse model by administration of triiodothyronine and lipopolysaccharide, and then to examine the effects of ghrelin on this model.

METHODS

We evaluated the use of serum IL-6 levels as a representative marker of hypercytokinemia in patients with TS. To establish the mouse model, preliminary experiments were conducted to determine the non-lethal doses of triiodothyronine and lipopolysaccharide when administered individually. As a TS model, C57BL/6 mice were administered with triiodothyronine 1.0 mg/kg (subcutaneously, once daily for seven consecutive days) and lipopolysaccharide 0.5 mg/kg (intraperitoneally, on day 7) to develop a lethal model with approximately 30% survival on day 8. We assessed the survival ratio, mouse sepsis scores and blood biomarkers (IL-6, metanephrine, alanine aminotransferase) and evaluated the effects of ghrelin 300 µg/kg on these parameters in TS model.

RESULTS

Serum IL-6 was increased in patients with TS compared with those with Graves' disease as the diseased control (18.2 vs. 2.85 pg/mL, P < .05, n = 4 each). The dosage for the murine TS model was triiodothyronine 1.0 mg/kg and lipopolysaccharide 0.5 mg/kg. The TS model group had increased mouse sepsis score, serum IL-6, metanephrine and alanine aminotransferase. In this model, the ghrelin improved the survival rate to 66.7% (P < .01, vs. 0% [saline-treated group]) as well as the mouse sepsis score, and it decreased the serum IL-6 and metanephrine.

CONCLUSION

We established an animal model of TS that exhibits pathophysiological states similar to human TS with induction of serum IL-6 and other biomarkers by administration of T3 and LPS. The results suggest the potential effectiveness of ghrelin for TS in humans.

Signatures of metabolic diseases on spermatogenesis and testicular metabolism

Diets leading to caloric overload are linked to metabolic disorders and reproductive function impairment. Metabolic and hormonal abnormalities stand out as defining features of metabolic disorders, and substantially affect the functionality of the testis. Metabolic disorders induce testicular metabolic dysfunction, chronic inflammation and oxidative stress. The disruption of gastrointestinal, pancreatic, adipose tissue and testicular hormonal regulation induced by metabolic disorders can also contribute to a state of compromised fertility. In this Review, we will delve into the effects of high-fat diets and metabolic disorders on testicular metabolism and spermatogenesis, which are crucial elements for male reproductive function. Moreover, metabolic disorders have been shown to influence the epigenome of male gametes and might have a potential role in transmitting phenotype traits across generations. However, the existing evidence strongly underscores the unmet need to understand the mechanisms responsible for transgenerational paternal inheritance of male reproductive function impairment related to metabolic disorders. This knowledge could be useful for developing targeted interventions to prevent, counteract, and most of all break the perpetuation chain of male reproductive dysfunction associated with metabolic disorders across generations.

Growth hormone promotes myelin repair after chronic hypoxia via triggering pericyte-dependent angiogenesis

White matter injury (WMI) causes oligodendrocyte precursor cell (OPC) differentiation arrest and functional deficits, with no effective therapies to date. Here, we report increased expression of growth hormone (GH) in the hypoxic neonatal mouse brain, a model of WMI. GH treatment during or post hypoxic exposure rescues hypoxia-induced hypomyelination and promotes functional recovery in adolescent mice. Single-cell sequencing reveals that Ghr mRNA expression is highly enriched in vascular cells. Cell-lineage labeling and tracing identify the GHR-expressing vascular cells as a subpopulation of pericytes. These cells display tip-cell-like morphology with kinetic polarized filopodia revealed by two-photon live imaging and seemingly direct blood vessel branching and bridging. Gain-of-function and loss-of-function experiments indicate that GHR signaling in pericytes is sufficient to modulate angiogenesis in neonatal brains, which enhances OPC differentiation and myelination indirectly. These findings demonstrate that targeting GHR and/or downstream effectors may represent a promising therapeutic strategy for WMI.

Examining linaclotide for the treatment of chronic idiopathic constipation

INTRODUCTION

Chronic idiopathic constipation (CIC) is characterized by infrequent bowel movements and hard stools lasting for at least three months or longer. This disease affects 8-12% of the US population and 10-17% of the world population. Treatment and management involve identifying the primary cause, changing dietary habits, and adequate physical activity. Linaclotide is a guanylate cyclase-agonist acting locally in the luminal surface of the intestinal enterocyte leading to a signal transduction cascade, activation of the cystic fibrosis transmembrane conductance regulator (CFTR), thus increasing secretion of chloride and bicarbonate into the intestinal lumen with eventual increased intestinal fluid and faster transit time.

AREAS COVERED

We reviewed multiple studies and did a thorough literature review on CIC including its pathophysiology. Through this literature review, we were able to discuss and give the context and rationale for drug regimens indicated for CIC.

EXPERT OPINION

The era we live in right now is akin to nutrient-rich and fertilized soil as knowledge and resources are abundant. The opportunities and potential are endless. Constipation being more extensively studied, our understanding of medications and diseases broadens, leading to novel medications being discovered. Linaclotide is a pioneer in this aspect and can pave the way for future generations.

Differential peptide-dependent regulation of growth hormone (GH): A comparative analysis in pituitary cultures of reptiles, birds, and mammals

Growth hormone (GH) is a pituitary protein that exerts pleiotropic roles in vertebrates. The mechanisms regulating GH synthesis and secretion are finely controlled by hypothalamic neuropeptides and other factors. These processes have been considerably studied in mammals but are still poorly understood in other groups. To better understand the pituitary GH regulation during vertebrate phylogeny, we compared the effects of incubating several peptides on cultures of ex-vivo pituitary fragments obtained from representative specimens of reptiles (iguana), birds (chicken) and mammals (rat). The peptides used were: growth hormone-releasing hormone (GHRH), thyrotropin-releasing hormone (TRH), pituitary adenylate cyclase-activating polypeptide (PACAP), ghrelin, gonadotropin-releasing hormone (GnRH), and somatostatin (SST). In rat pituitary cultures, GH secretion was stimulated by GHRH and TRH, while gh mRNA expression was increased by GHRH and PACAP. In the case of chicken pituitaries, GH release was promoted by GHRH, ghrelin, PACAP, and GnRH, although the latter two had a dual effect since at a shorter incubation time they decreased GH secretion; in turn, gh mRNA expression was significantly stimulated by TRH, PACAP, and GnRH. The most intense effects were observed in iguana pituitary cultures, where GH secretion was significantly augmented by GHRH, PACAP, TRH, ghrelin, and GnRH; while gh mRNA expression was stimulated by GHRH, TRH, and PACAP, but inhibited by ghrelin and SST. Also, in the three species, SST was able to block the GHRH-stimulated GH release. Furthermore, it was found that the expression of Pou1f1 mRNA was increased with greater potency by GHRH and PACAP in the iguana, than in chicken or rat pituitary cultures. Additionally, in-silico analysis of the gh gene promoter structures in the three species showed that the reptilian promoter has more Pit-1 consensus binding sites than their avian and mammalian counterparts. Taken together, results demonstrate that pituitary peptide-mediated GH regulatory mechanisms are differentially controlled along vertebrate evolution.

Prevention, Assessment, and Management of Malnutrition in Older Adults with Early Stages of Cognitive Disorders

Malnutrition is common in older adults, and its risk is greater in those living with dementia. Relative to cognitively healthy peers, the prevalence of malnutrition is also increased in individuals with early stages of cognitive disorders owing to pathophysiological, cognitive, and psychosocial changes related to cognitive impairment. Malnutrition is associated with adverse health outcomes, including faster cognitive and functional decline. Here, we provide an overview of the prevention, assessment, and management of malnutrition in older adults, with a special focus on the aspects that are important to consider in individuals with early stages of cognitive disorders. Strategies to prevent malnutrition include systematic screening for malnourishment using validated tools to detect those at risk. If the screening reveals an increased risk of malnutrition, a detailed assessment including the individual's nutritional, medical, and functional status as well as dietary intake should be performed. The management of malnutrition in the early stages of cognitive disorders should be based on the findings of a comprehensive assessment and be personalized according to the individual's specific characteristics. In the article, we also provide an overview of the evidence on vitamin supplements and specific dietary patterns to prevent cognitive decline or attenuate its progression.

Impact of Nutritional Status of Patients with Head and Neck Squamous Cell Carcinoma on the Expression Profile of Ghrelin, Irisin, and Titin

The goal of this paper was the evaluation of the changes in the expression profile of irisin, ghrelin, and titin in the carcinoma tissue and in the blood of patients with head and neck squamous cell carcinoma (HNSCC), including determining the profile of their expression in relation to patient nutrition. The study included 56 patients with diagnosed squamous cell carcinoma of HNSCC in the T3 and T4 stages of the disease. Healthy control tissue specimens were collected from an area 10 mm outside the histologically negative margin. In turn, the blood and serum from the control group came from healthy volunteers treated for non-oncologic reasons (n = 70). The molecular analysis allowed us to determine the profile of irisin, ghrelin, and titin methylation, evaluate their expression on the level of mRNA (quantitative Reverse Transcription Polymerase Chain Reaction; qRT-PCR) and protein (Enzyme-Linked Immunosorbent Assay Reaction; ELISA) in the carcinoma tissue and the margin of healthy tissue, as well as in serum of patients in the study and control groups. At the start of our observations, a Body Mass Index (BMI) < 18.5 was noted in 42 of the patients, while six months after the treatment a BMI < 18.5 was noted in 29 patients. We also noted a decrease in the expression of irisin, ghrelin, and titin both on the level of mRNA and protein, as well as a potential regulation of their expression via DNA methylation. There is no convincing evidence that the proteins assayed in the present work are specific with regard to HNSSC.

Feeding during the resting phase causes gastrointestinal tract dysfunction and desynchronization of metabolic and neuronal rhythms in rats

BACKGROUND

Disrupted circadian rhythms may result from a misalignment between the environmental cycles (due to shift work, sleep restriction, feeding at an unusual time of day) and endogenous rhythms or by physiological aging. Among the numerous adverse effects, disrupted rhythms affect the brain-gut axis, contributing to the pathogenesis of several diseases in the gastrointestinal tract, for example, abdominal pain, constipation, gastric dyspepsia, inflammatory bowel disease, irritable bowel syndrome, and others.

METHODS

This study evaluated the rat gastric emptying, gastrointestinal motility, a clock gene, gut hormones, and the neuron activity on the nucleus of tractus solitarius (NTS), area postrema (AP), and the dorsal motor nucleus of the vagus (DMV) in rats with restricted food access to the rest phase for 4 weeks.

KEY RESULTS

Our results show that food restricted to the rest light period disturbed the expression pattern of a series of transcripts, including metabolic and circadian regulation. Also, the secretion of gastrointestinal hormones, gastric emptying, intestinal motility, and NTS, AP, and DMV activity were altered.

CONCLUSIONS & INFERENCES

These data indicate the importance of the time of the day food is ingested on the regulation of energy balance and the endocrine activity of the stomach and small intestine, emphasizing the importance of food as a powerful circadian synchronizer and an essential factor for the triggering of gastrointestinal diseases and metabolic problems. These findings offer a novel clue regarding the obesity-promoting effect attributed to feeding time and open the possibility of treating this and other intestinal disorders.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Diabetes Remission After LRYGBP With and Without Fundus Resection: a Randomized Clinical Trial

BACKGROUND

Glycemic control, after metabolic surgery, is achieved in two stages, initially with neuroendocrine alterations and in the long-term with sustainable weight loss. The resection of the gastric fundus, as the major site of ghrelin production, is probably related with optimized glucose regulation. The aim of the present study is to investigate whether the modification of laparoscopic Roux-en-Y gastric bypass (LRYGBP) with fundus resection offers superior glycemic control, compared to typical LRYGBP.

MATERIALS AND METHODS

Participants were 24 patients with body mass index (BMI) ≥40kg/m2 and type II diabetes mellitus (T2DM), who were randomly assigned to undergo LRYGBP and LRYGBP with fundus resection (LRYGBP+FR). Gastrointestinal (GI) hormones [ghrelin, glucagon-like-peptide-1 (GLP-1), peptide-YY (PYY)] and glycemic parameters (glucose, insulin, HbA1c, C-peptide, insulinogenic index, HOMA-IR) were measured preoperatively, at 6 and 12 months during an oral glucose tolerance test (OGTT).

RESULTS

Ninety-five percent of patients showed complete remission of T2DM after 12 months. LRYGBP+FR was not related with improved glycemic control, compared to LRYGBP. Ghrelin levels were not significantly reduced at 6 and 12 months after LRYGBP+FR. GLP-1 and PYY levels were remarkably increased postprandially in both groups at 6 and 12 months postoperatively (p<0.01). Patients who underwent LRYGBP+FR achieved a significantly lower BMI at 12 months in comparison to LRYGBP (p<0.05).

CONCLUSION

Fundus resection is not associated with improved glycemic regulation, compared to typical LRYGBP and the significant decrease in BMI after LRYGBP+FR has to be further confirmed with longer follow-up.

Relamorelin in Gastroparesis and Diabetic Gastroparesis: A Meta-Analysis on Its Efficacy and Safety

This meta-analysis aimed to evaluate the efficacy and safety of relamorelin, a synthetic ghrelin receptor agonist, for the treatment of gastroparesis and diabetic gastroparesis. A total of 1,033 participants from five randomized controlled trials were included. The primary outcome was the mean change in gastric emptying time from baseline. Relamorelin demonstrated a statistically significant improvement in gastric emptying time with a mean difference of -11.40 minutes compared to the placebo group. Furthermore, a significant improvement was observed specifically in diabetic gastroparesis patients, with a mean difference of -8.43 minutes. However, adverse effects, such as headaches, dizziness, and gastrointestinal symptoms, were more prevalent in the relamorelin group. Despite these adverse effects, the study concludes that relamorelin offers a promising avenue for gastroparesis treatment, especially given the limited existing therapeutic options. This comprehensive meta-analysis synthesizes existing evidence to inform clinical practice and guides future research in this domain.

Association of dietary oxidative balance score and sleep duration with the risk of mortality: prospective study in a representative US population

OBJECTIVE

We investigated the association between dietary oxidative balance score (DOBS) and mortality and whether this association can be modified by sleep duration.

DESIGN

We calculated DOBS to estimate the overall oxidative effects of the diet, with higher DOBS reflecting more antioxidant intake and less pro-oxidant intake. Cox proportional hazards models were employed to examine the associations between DOBS and all-cause, CVD and cancer mortality in the general population and people with different sleep durations.

SETTING

Prospective analysis was conducted using data from the US National Health and Nutrition Examination Survey (NHANES, 2005-2015).

PARTICIPANTS

A total of 15 991 US adults with complete information on dietary intake, sleep duration and mortality were included.

RESULTS

During a median follow-up of 7·4 years, 1675 deaths were observed. Participants in the highest quartile of DOBS were significantly associated with the lower risk of all-cause mortality (hazard ratio (HR) = 0·75; 95 % CI 0·61, 0·93) compared with those in the lowest. Furthermore, we found statistically significant interactions between DOBS and sleep duration on all-cause mortality (P interaction = 0·021). The inverse association between DOBS and all-cause mortality was significant in short sleepers (HR = 0·66, 95 % CI 0·48, 0·92), but not in normal and long sleepers.

CONCLUSIONS

Our study observed that higher DOBS was associated with lower all-cause mortality, and this association appeared to be stronger among short sleepers. This study provides nutritional guidelines for improving health outcomes in adults, especially for short sleepers.

Circulating ghrelin levels in patients with gastric cancer: a systematic review and meta-analysis

Background

Ghrelin plays a critical role in regulating energy metabolism and homeostasis. The association between circulating ghrelin levels and gastric cancer has not been systematically analyzed.

Objective

This work explored the association between circulating ghrelin levels and gastric cancer.

Methods

The literature search for relevant articles published until November 2022 was performed using PubMed, Cochrane Library, EMBASE, and Web of Science with the keywords "ghrelin" and "gastric cancer". Standardized mean differences (SMD) with 95% confidence intervals were used to measure the effectiveness. We assessed pooled data by use of a random-effects model.

Results

Of 5,302 identified studies, nine were included (N=3,196 participants). Circulating ghrelin levels were lower in gastric cancer patients (SMD=-0.255, 95%CI: -0.528 to 0.017, P < 0.00001), but with high heterogeneity (I2 = 88.8%).

Conclusion

The circulating ghrelin levels in patients with gastric cancer were lower than in controls. However, there was heterogeneity among results; therefore, studies with larger sample sizes are recommended.

Mechanistic insights on impact of Adenosine monophosphate-activated protein kinase (AMPK) mediated signalling pathways on cerebral ischemic injury

Cerebral ischemia is the primary cause of morbidity and mortality worldwide due to the perturbations in the blood supply to the brain. The brain triggers a cascade of complex metabolic and cellular defects in response to ischemic stress. However, due to the disease heterogeneity and complexity, ischemic injury's metabolic and cellular pathologies remain elusive, and the link between various pathological mechanisms is difficult to determine. Efforts to develop effective treatments for these disorders have yielded limited efficacy, with no proper cure available to date. Recent clinical and experimental research indicates that several neuronal diseases commonly coexist with metabolic dysfunction, which may aggravate neurological symptoms. As a result, it stands to a reason that metabolic hormones could be a potential therapeutic target for major NDDs. Moreover, fasting signals also influence the circadian clock, as AMPK phosphorylates and promotes the degradation of the photo-sensing receptor (cryptochrome). Here, the interplay of AMPK signaling between metabolic regulation and neuronal death and its role for pathogenesis and therapeutics has been studied. We have also highlighted a significant signaling pathway, i.e., the adenosine monophosphate-activated protein kinase (AMPK) involved in the relationship between the metabolism and ischemia, which could be used as a target for future studies therapeutics, and review some of the clinical progress in this area.

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.

The role of the gastric fundus in glycemic control

PURPOSE

Ghrelin, one of the most studied gut hormones, is mainly produced by the gastric fundus. Abundant evidence exists from preclinical and clinical studies underlining its contribution to glucose regulation. In the following narrative review, the role of the gastric fundus in glucose regulation is summarized and we investigate whether its resection enhances glycemic control.

METHODS

An electronic search was conducted in the PubMed® database and in Google Scholar® using a combination of medical subject headings (MeSH). We examined types of metabolic surgery, including, in particular, gastric fundus resection, either as part of laparoscopic sleeve gastrectomy (LSG) or modified laparoscopic gastric bypass with fundus resection (LRYGBP + FR), and the contribution of ghrelin reduction to glucose regulation.

RESULTS

Fourteen human studies were judged to be eligible and included in this narrative review. Reduction of ghrelin levels after fundus resection might be related to early glycemic improvement before significant weight loss is achieved. Long-term data regarding the role of ghrelin reduction in glucose homeostasis are sparse.

CONCLUSION

The exact role of ghrelin in achieving glycemic control is still ambiguous. Data from human studies reveal a potential contribution of ghrelin reduction to early glycemic improvement, although further well-designed studies are needed.

Effect of Continuous Positive Airway Pressure on Changes of Plasma/Serum Ghrelin and Evaluation of These Changes between Adults with Obstructive Sleep Apnea and Controls: A Meta-Analysis

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) can be related to high ghrelin hormone levels that may encourage additional energy intake. Herein, a new systematic review and meta-analysis were performed to check the changes in serum/plasma levels of ghrelin in adults with OSA compared to controls, as well as before compared after continuous positive airway pressure (CPAP) therapy in adults with OSA.

MATERIALS AND METHODS

Four main databases were systematically and comprehensively searched until 17 October 2022, without any restrictions. For assessing the quality, we used the Joanna Briggs Institute (JBI) critical appraisal checklist adapted for case-control studies and the National Institutes of Health (NIH) quality assessment tool for before-after studies. The effect sizes were extracted by the Review Manager 5.3 software for the blood of ghrelin in adults with OSA compared with controls, as well as before and after CPAP therapy.

RESULTS

Fifteen articles involving thirteen studies for case-control studies and nine articles for before-after studies were included. The pooled standardized mean differences were 0.30 (95% confidence interval (CI): -0.02, 0.61; p = 0.07; I² = 80%) and 0.10 (95% CI: -0.08, 0.27; p = 0.27; I² = 42%) for case-control and before-after studies, respectively. For thirteen case-control studies, nine had moderate and four high qualities, whereas for nine before-after studies, five had good and four fair qualities. Based on the trial sequential analysis, more studies are needed to confirm the pooled results of the analyses of blood ghrelin levels in case-control and before-after studies. In addition, the radial plot showed outliers for the analysis of case-control studies that they were significant factors for high heterogeneity.

CONCLUSIONS

The findings of the present meta-analysis recommended that the blood levels of ghrelin had no significant difference in the adults with OSA compared with the controls, nor did they have significant difference in adults with OSA before compared with after CPAP therapy. The present findings need to be confirmed in additional studies with more cases and higher qualities.

Connecting insufficient sleep and insomnia with metabolic dysfunction

The global epidemic of obesity and type 2 diabetes parallels the rampant state of sleep deprivation in our society. Epidemiological studies consistently show an association between insufficient sleep and metabolic dysfunction. Mechanistically, sleep and circadian rhythm exert considerable influences on hormones involved in appetite regulation and energy metabolism. As such, data from experimental sleep deprivation in humans demonstrate that insufficient sleep induces a positive energy balance with resultant weight gain, due to increased energy intake that far exceeds the additional energy expenditure of nocturnal wakefulness, and adversely impacts glucose metabolism. Conversely, animal models have found that sleep loss-induced energy expenditure exceeds caloric intake resulting in net weight loss. However, animal models have significant limitations, which may diminish the clinical relevance of their metabolic findings. Clinically, insomnia disorder and insomnia symptoms are associated with adverse glucose outcomes, though it remains challenging to isolate the effects of insomnia on metabolic outcomes independent of comorbidities and insufficient sleep durations. Furthermore, both pharmacological and behavioral interventions for insomnia may have direct metabolic effects. The goal of this review is to establish an updated framework for the causal links between insufficient sleep and insomnia and risks for type 2 diabetes and obesity.

Association of maternal body composition and diet on breast milk hormones and neonatal growth during the first month of lactation

INTRODUCTION

Preterm birth is associated with altered growth patterns and an increased risk of cardiometabolic diseases, with breast milk (BM) being a counteracting factor. Preterm infants also show alterations in adipokines and gut hormones influencing appetite and metabolism. Since these hormones are present in BM, it is possible that their levels may equilibrate deficiencies improving infant growth. We aimed to assess 1) the BM levels of ghrelin, resistin, leptin, insulin, peptide YY, and the gastrointestinal peptide in women with preterm and term labor; 2) the relationship between BM hormones and neonatal growth; and 3) the influence of maternal body composition and diet on these BM hormones.

METHODS

BM from 48 women (30 term and 18 preterm labor) was collected at days 7, 14, and 28 of lactation. Maternal body composition was evaluated by bioimpedance, and neonate anthropometric parameters were collected from medical records. The maternal dietary pattern was assessed by a 72-h dietary recall at days 7 and 28 of lactation. BM hormones were analyzed by the U-Plex Ultra-sensitive method. Data were analyzed using linear regression models. BM from women with preterm labor had lower ghrelin levels, with the other hormones being significantly higher compared to women with term delivery.

RESULTS

In premature infants, growth was positively associated with BM ghrelin, while, in term infants, it was positively associated with insulin and negatively with peptide YY. In the first week of lactation, women with preterm labor had higher body fat compared to women with term labor. In this group, ghrelin levels were positively associated with maternal body fat and with fiber and protein intake. In women with term labor, no associations between anthropometric parameters and BM hormones were found, and fiber intake was negatively associated with peptide YY.

DISCUSSION

Preterm labor is a factor influencing the levels of BM adipokines and gut hormones, with BM ghrelin being a relevant hormone for premature infant growth. Since ghrelin is lower in BM from women with preterm labor and the levels are associated with maternal fat storage and some dietary components, our data support the importance to monitor diet and body composition in women who gave birth prematurely to improve the BM hormonal status.

Obstructive Sleep Apnea, Circadian Clock Disruption, and Metabolic Consequences

Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of apnea and hypopnea during sleep. It is associated with various cardiovascular and metabolic complications, including type 2 diabetes mellitus (T2DM) and obesity. Many pathways can be responsible for T2DM development in OSA patients, e.g., those related to HIF-1 and SIRT1 expression. Moreover, epigenetic mechanisms, such as miRNA181a or miRNA199, are postulated to play a pivotal role in this link. It has been proven that OSA increases the occurrence of circadian clock disruption, which is also a risk factor for metabolic disease development. Circadian clock disruption impairs the metabolism of glucose, lipids, and the secretion of bile acids. Therefore, OSA-induced circadian clock disruption may be a potential, complex, underlying pathway involved in developing and exacerbating metabolic diseases among OSA patients. The current paper summarizes the available information pertaining to the relationship between OSA and circadian clock disruption in the context of potential mechanisms leading to metabolic disorders.

G protein-coupled receptor interactions and modification of signalling involving the ghrelin receptor, GHSR1a

The growth hormone secretagogue receptor 1a (GHSR1a) is intriguing because of its potential as a therapeutic target and its diverse molecular interactions. Initial studies of the receptor focused on the potential therapeutic ability for growth hormone (GH) release to reduce wasting in aging individuals, as well as food intake regulation for treatment of cachexia. Known roles of GHSR1a now extend to regulation of neurogenesis, learning and memory, gastrointestinal motility, glucose/lipid metabolism, the cardiovascular system, neuronal protection, motivational salience, and hedonic feeding. Ghrelin, the endogenous agonist of GHSR1a, is primarily located in the stomach and is absent from the central nervous system (CNS), including the spinal cord. However, ghrelin in the circulation does have access to a small number of CNS sites, including the arcuate nucleus, which is important in feeding control. At some sites, such as at somatotrophs, GHSR1a has high constitutive activity. Typically, ghrelin-dependent and constitutive GHSR1a activation occurs via Gα_q/11 pathways. In vitro and in vivo data suggest that GHSR1a heterodimerises with multiple G protein-coupled receptors (GPCRs), including dopamine D1 and D2, serotonin 2C, orexin, oxytocin and melanocortin 3 receptors (MCR3), as well as the MCR3 accessory protein, MRAP2, providing possible mechanisms for its many physiological effects. In all cases, the receptor interaction changes downstream signalling and the responses to receptor agonists. This review discusses the signalling mechanisms of GHSR1a alone and in combination with other GPCRs, and explores the physiological consequences of GHSR1a coupling with other GPCRs.

Acylation, a Conductor of Ghrelin Function in Brain Health and Disease

Acyl-ghrelin (AG) is an orexigenic hormone that has a unique octanoyl modification on its third serine residue. It is often referred to as the “hunger hormone” due to its involvement in stimulating food intake and regulating energy homeostasis. The discovery of the enzyme ghrelin-O-acyltransferase (GOAT), which catalyses ghrelin acylation, provided further insights into the relevance of this lipidation process for the activation of the growth hormone secretagogue receptor (GHS-R) by acyl-ghrelin. Although acyl-ghrelin is predominantly linked with octanoic acid, a range of saturated fatty acids can also bind to ghrelin possibly leading to specific functions. Sources of ghrelin acylation include beta-oxidation of longer chain fatty acids, with contributions from fatty acid synthesis, the diet, and the microbiome. In addition, both acyl-ghrelin and unacyl-ghrelin (UAG) have feedback effects on lipid metabolism which in turn modulate their levels. Recently we showed that whilst acyl-ghrelin promotes adult hippocampal neurogenesis and enhances memory function, UAG inhibits these processes. As a result, we postulated that the circulating acyl-ghrelin:unacyl-ghrelin (AG:UAG) ratio might be an important regulator of neurogenesis and cognition. In this review, we discuss emerging evidence behind the relevance of ghrelin acylation in the context of brain physiology and pathology, as well as the current challenges of identifying the provenance of the acyl moiety.

Role of the Ghrelin System in Colorectal Cancer

The ghrelin system contains several components (e.g., ghrelin with growing number of alternative peptides, growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT) and participates in regulation of a number of key processes of gastrointestinal (GI) tract cancer progression, including cell proliferation, migration, invasion, apoptosis, inflammation, and angiogenesis. However, its exact role in promoting or inhibiting cancer progression is still unclear. Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Molecular studies suggest an autocrine/paracrine mechanism for the secretion of ghrelin in colorectal carcinogenesis and its contribution to its initial stages. However, the signalling pathways of CRC development involving the ghrelin system are poorly understood. Potential mechanisms of colon carcinogenesis involving components of the ghrelin system were previously described in an animal model and in in vitro studies. However, the diagnostic–prognostic role of serum ghrelin concentrations, tissue expression, or genetic changes of this system in various stages of CRC progression remains an open case. Thus, the aim of this study is to discuss the role of the ghrelin system in colon carcinogenesis, diagnostics and CRC prognostics, as well as the results of studies on the use of ghrelin and its analogues in the therapy of CRC-related syndromes (e.g., cachexia and sarcopenia).

Correlation of body mass index to Ghrelin and IGF-1 among children with short stature

OBJECTIVE

To assess the BMI among children with Growth Hormone Deficiency (GHD) and Idiopathic Short Stature (ISS) and its correlation to ghrelin, Growth Hormone (GH), and Insulin-like Growth Factor-1 (IGF-1) levels.

METHODS

A cross-sectional descriptive study in which 42 patients attending the Pediatric endocrine clinic were enrolled, allocated into two groups: group I: GHD children; group II: ISS children. Ghrelin, IGF-1 and GH in both groups were measured.

RESULTS

Ghrelin was significantly higher among GHD group (p < 0.001). Overall, there was a strong negative correlation between IGF-1 and ghrelin (r = -0.977, p-value = < 0.001) while a moderate positive correlation between ghrelin and BMI (r = 0.419, p-value = 0.006). There was a weak positive non-significant correlation between IGF-1 and BMI (r = 0.276, p-value = 0.077). In GHD group, there was a weak positive non-significant correlation between ghrelin and GH_max measurement (r = 0.052, p-value = 0.824), while a weak negative non-significant correlation between both variables in ISS group (r = -0.243, p-value = 0.288). In GHD group, there was a moderate positive correlation between ghrelin and BMI (r = 0.500, p-value = 0.021), but weak negative non-significant correlation between both variables in ISS group (r = -0.255, p-value = 0.265).

CONCLUSION

There was a negative feedback loop between ghrelin and IGF-1, whereas a positive feedback between ghrelin and BMI. BMI was more affected in the ISS group but was non-significantly correlated with ghrelin. There was no significant compensatory response of ghrelin suggesting its contribution to the pathogenesis of ISS.

The Impact of Sleep-Disordered Breathing on Ghrelin, Obestatin, and Leptin Profiles in Patients with Obesity or Overweight

Background: The impact of concomitant obesity and sleep disorders on neuropeptides related to energy balance is poorly understood. The aim of this study was to assess the nocturnal profile of total ghrelin, obestatin, and leptin in patients with elevated BMI and to investigate the impact of breathing-related sleep disorders on these hormone levels. Methods: The study involved 58 patients with suspicion of obstructive sleep apnea (OSA). Patients underwent anthropometric and sleep examination and measurements of night ghrelin, leptin, and obestatin levels. Results: In patients with OSA (n = 46), recognized on the basis of sleep examination outcomes, the correlation of anthropometric measurements with parameters of sleep disorders and ghrelin levels was observed, contrary to the control group (n = 12). In the OSA group, levels of ghrelin were significantly lower than in the control group at 5:00 and 7:00. Levels of leptin in the OSA group were also lower than those in the control groups (not statistically significant). Profiles of obestatin in both groups were similar. Conclusions: Our results confirm the relationship between obesity and sleep-disordered breathing. Both these disorders affect ghrelin levels—parameters of obesity negatively correlate with hormone concentration, and OSA seems to lower ghrelin values in the second half of the night.

The Complex Relationship Between Microbiota, Immune Response and Creeping Fat in Crohn's Disease

In the last decade, there has been growing interest in the pathological involvement of hypertrophic mesenteric fat attached to the serosa of the inflamed intestinal segments involved in Crohn's disease [CD], known as creeping fat. In spite of its protective nature, creeping fat harbours an aberrant inflammatory activity which, in an already inflamed intestine, may explain why creeping fat is associated with a greater severity of CD. The transmural inflammation of CD facilitates the interaction of mesenteric fat with translocated intestinal microorganisms, contributing to activation of the immune response. This may be not the only way in which microorganisms alter the homeostasis of this fatty tissue: intestinal dysbiosis may also impair xenobiotic metabolism. All these CD-related alterations have a functional impact on nuclear receptors such as the farnesoid X receptor or the peroxisome proliferator-activated receptor γ, which are implicated in regulation of the immune response, adipogenesis and the maintenance of barrier function, as well as on creeping fat production of inflammatory-associated cells such as adipokines. The dysfunction of creeping fat worsens the inflammatory course of CD and may favour intestinal fibrosis and fistulizing complications. However, our current knowledge of the pathophysiology and pathogenic role of creeping fat is controversial and a better understanding might provide new therapeutic targets for CD. Here we aim to review and update the key cellular and molecular alterations involved in this inflammatory process that link the pathological components of CD with the development of creeping fat.

Exploring barriers, motivators and solutions to achieve a healthy lifestyle among undergraduate student nurses

BACKGROUND

Many preregistration student nurses tend to be overweight or obese and have unhealthy lifestyles.

AIMS

This study aimed to quantify the prevalence of these issues, to identify barriers to adopting a healthy lifestyle as well as potential solutions, and to explore the use of smartphone health apps.

METHODS

An online questionnaire examined diet and physical activity habits, general health and attitudes to eHealth. An in-class questionnaire with a new sample assessed current lifestyle, barriers to healthier living, support needed to achieve goals and the use of health apps.

FINDINGS

Half of student nurses were overweight or obese and only 41% met the recommended levels of physical activity. An in-class questionnaire revealed that more than half of them wanted to have a better diet and to exercise more.

CONCLUSION

Generally, student nurses were not satisfied with their current lifestyles. A lack of motivation and time were the most frequently reported barriers; an intervention focusing on motivational support could be an acceptable and effective means of achieving and sustaining positive behaviour change.

The Role of Ghrelin/GHS-R1A Signaling in Nonalcohol Drug Addictions

Drug addiction causes constant serious health, social, and economic burden within the human society. The current drug dependence pharmacotherapies, particularly relapse prevention, remain limited, unsatisfactory, unreliable for opioids and tobacco, and even symptomatic for stimulants and cannabinoids, thus, new more effective treatment strategies are researched. The antagonism of the growth hormone secretagogue receptor type A (GHS-R1A) has been recently proposed as a novel alcohol addiction treatment strategy, and it has been intensively studied in experimental models of other addictive drugs, such as nicotine, stimulants, opioids and cannabinoids. The role of ghrelin signaling in these drugs effects has also been investigated. The present review aims to provide a comprehensive overview of preclinical and clinical studies focused on ghrelin's/GHS-R1A possible involvement in these nonalcohol addictive drugs reinforcing effects and addiction. Although the investigation is still in its early stage, majority of the existing reviewed experimental results from rodents with the addition of few human studies, that searched correlations between the genetic variations of the ghrelin signaling or the ghrelin blood content with the addictive drugs effects, have indicated the importance of the ghrelin's/GHS-R1As involvement in the nonalcohol abused drugs pro-addictive effects. Further research is necessary to elucidate the exact involved mechanisms and to verify the future potential utilization and safety of the GHS-R1A antagonism use for these drug addiction therapies, particularly for reducing the risk of relapse.

An evolving view on food viscosity regulating gastric emptying

Viscosity is a property of most foods. The consumption of the high-viscosity food is associated with a variety of physiological responses, one of which is their ability to regulate gastric emptying and modulate postprandial glycemic response. Gastric emptying has been proven to be a key step affecting the digestion and absorption of food, whereas, the relationship between viscosity and gastric emptying is still far away from being understood. Here, we reviewed the factors that influence food viscosity and food viscosity changes during digestion. Besides, the effect of food viscosity on gastric emptying and food-viscosity-physiological response were highlighted. Finally, "quantitative relationship" of viscosity and gastric emptying was discussed. This review can contribute to the understanding that how food viscosity affects gastric emptying, and help for developing foods that could control satiety and manage body weight for the specific populations.

Ghrelin alleviates 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y cells

Ghrelin is a neuropeptide that has various physiological functions and has been demonstrated to be neuroprotective in a number of neurological disease models. However, the underlying mechanisms of ghrelin in Parkinson’s disease remain largely unexplored. The current study aimed to study the effects of ghrelin in a 6-hydroxydopamine (6-OHDA)-induced Parkinson’s disease model and evaluate the potential underlying mechanisms. In the present study, we treated an SH-SY5Y cell model with 6-OHDA, and observed that pretreatment with different concentrations of ghrelin (1, 10, and 100 nM) for 30 minutes relieved the neurotoxic effects of 6-OHDA, as revealed by Cell Counting Kit-8 and Annexin V/propidium iodide (PI) apoptosis assays. Reverse transcription quantitative polymerase chain reaction and western blot assay results demonstrated that 6-OHDA treatment upregulated α-synuclein and lincRNA-p21 and downregulated TG-interacting factor 1 (TGIF1), which was predicted as a potential transcription regulator of the gene encoding α-synuclein (SNCA). Ghrelin pretreatment was able to reverse the trends caused by 6-OHDA. The Annexin V/PI apoptosis assay results revealed that inhibiting either α-synuclein or lincRNA-p21 expression with small interfering RNA (siRNA) relieved 6-OHDA-induced cell apoptosis. Furthermore, inhibiting lincRNA-p21 also partially upregulated TGIF1. By retrieving information from a bioinformatics database and performing both double luciferase and RNA immunoprecipitation assays, we found that lincRNA-p21 and TGIF1 were able to form a double-stranded RNA-binding protein Staufen homolog 1 (STAU1) binding site and further activate the STAU1-mediated mRNA decay pathway. In addition, TGIF1 was able to transcriptionally regulate α-synuclein expression by binding to the promoter of SNCA. The Annexin V/PI apoptosis assay results showed that either knockdown of TGIF1 or overexpression of lincRNA-p21 notably abolished the neuroprotective effects of ghrelin against 6-OHDA-induced neurotoxicity. Collectively, these findings suggest that ghrelin exerts neuroprotective effects against 6-OHDA-induced neurotoxicity via the lincRNA-p21/TGIF1/α-synuclein pathway.

CIRCULATING GHRELIN LEVELS AND SUSCEPTIBILITY TO COLORECTAL CÂNCER

BACKGROUND AND OBJECTIVE

Considering the association between colorectal cancer (CRC) and both insulin resistance and obesity, and the prominent role of ghrelin in these metabolic disorders, we explored whether plasma levels of ghrelin were associated with CRC. Moreover, in the patients with CRC the possible correlations between ghrelin and insulin, insulin resistance, and body mass index (BMI) as an indicator of obesity were examined.

METHODS

A total of 170 subjects, including 82 cases with CRC and 88 controls were enrolled in this study. Plasma levels of ghrelin, insulin, and glucose were measured in all the subjects using ELISA and glucose oxidase methods. Furthermore, insulin resistance was assessed by calculating HOMA-IR index.

RESULTS

The cases with CRC had decreased ghrelin levels (P<0.001) and a higher HOMA-IR index (P<0.001) than controls. Interestingly, when CRC patients were stratified based on tumor site, lower ghrelin levels and a higher HOMA-IR index were observed in the patients with either colon or rectal cancer vs. controls too. Additionally, there were an age and BMI-independent negative correlation between ghrelin levels and HOMA-IR (r=-0.365, P<0.05), and an age-independent negative correlation between ghrelin levels and BMI (r=-0.335, P<0.05) in the rectal subgroup.

CONCLUSION

Our findings support a role for ghrelin in connection with insulin resistance and obesity in CRC susceptibility; however, it needs to be corroborated by further studies.

Appetite regulation by plant-derived bioactive peptides for promoting health

Appetite is closely regulated not only by gut hormonal and neuronal peptides but also by exogenous peptides derived from food proteins. Food proteins are now recognized to contain many thousands of bioactive compounds that provide additional health benefits beyond their nutritional effects. Bioactive peptides are beneficial to the life and/or to regulate physiological functions. Although animal protein products have been widely applied in the food industry, exploring the possibilities of developing functional foods based on plant protein-derived peptides is considered attractive for achieving sustainable development goals. In addition, peptides from plant proteins have the potential to treat numerous diseases or risk factors and may therefore facilitate a healthy life expectancy. In this review, we discuss the identified plant-based bioactive peptides and their appetite regulating effects. Plant-based bioactive peptides may provide new opportunities to discover novel approaches that can improve and prevent diseases in a sustainable environment.

Interplay of KNDy and nNOS neurons: A new possible mechanism of GnRH secretion in the adult brain

Reproduction in mammals is favoured when there is sufficient energy available to permit the survival of offspring. Neuronal nitric oxide synthase expressing neurons produce nitric oxide in the proximity of the gonadotropin-releasing hormone neurons in the preoptic region. nNOS neurons are an integral part of the neuronal network controlling ovarian cyclicity and ovulation. Nitric oxide can directly regulate the activity of the GnRH neurons and play a vital role neuroendocrine axis. Kisspeptin neurons are essential for the GnRH pulse and surge generation. The anteroventral periventricular nucleus (AVPV), kisspeptin neurons are essential for GnRH surge generation. KNDy neurons are present in the hypothalamus's arcuate nucleus (ARC), co-express NKB and dynorphin, essential for GnRH pulse generation. Kisspeptin-neurokinin B-dynorphin (KNDy) neuroendocrine molecules of the hypothalamus are key components in the central control of GnRH secretion. The hypothalamic neurons kisspeptin, KNDy, nitric oxide synthase (NOS), and other mediators such as leptin, adiponectin, and ghrelin, play an active role in attaining puberty. Kisspeptin signalling is mediated by NOS, which further results in the secretion of GnRH. Neuronal nitric oxide is critical for attaining puberty, but its direct role in adult GnRH secretion is poorly understood. This review mainly focuses on the role of nNOS and its interplay with KNDy neurons in the hormonal regulation of reproduction.

Distribution and effect of ghrelin genotype on plasma lipid and apolipoprotein profiles in obese and nonobese Chinese subjects

PURPOSE

The hormone ghrelin has an important role in a wide range of metabolic and nonmetabolic processes. Ghrelin gene polymorphisms have been reported to influence obesity or lipid abnormalities in some ethnic groups. This study was conducted mainly to examine the possible association of ghrelin - 604 G > A and Leu72Met polymorphisms with obesity and related traits in a Southwest Chinese population.

METHODS

Three hundred and eighty-six Han Chinese individuals (118 obese and 268 normal weight control subjects) in the Chengdu area were studied using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Clinical and biochemical parameters were also analyzed.

RESULTS

The genotype and allele frequencies of ghrelin gene polymorphisms in participants with obesity showed no significant difference compared to those in nonobese controls. However, in the nonobese control group, carriers of genotype Met/Met at the Leu72Met site had higher serum TC and LDL-C concentrations than those of the Leu/Leu genotype (P < 0.05). When nonobese subjects were stratified by sex, the genotype-dependent effects on TC and LDL-C were more evident, although this was observed only in females. In addition, genotype-related effects on these lipid parameters at this site were observed in male obese subjects only.

CONCLUSIONS

The Leu72Met polymorphism of the ghrelin gene is associated with altered plasma TC and LDL-C concentrations, and the effects on TC and LDL-C levels are sex-dependent in both nonobese and obese subjects in the Chinese population of the Chengdu area.

Acylated Ghrelin Attenuates l-Thyroxin-induced Cardiac Damage in Rats by Antioxidant and Anti-inflammatory Effects and Downregulating Components of the Cardiac Renin-angiotensin System

ABSTRACT

This study investigated the protective effect of acylated ghrelin (AG) against l-thyroxin (l-Thy)-induced cardiac damage in rats and examined possible mechanisms. Male rats were divided into five intervention groups of 12 rats/group: control, control + AG, l-Thy, l-Thy + AG, and l-Thy + AG + [D-Lys3]-GHRP-6 (AG antagonist). l-Thy significantly reduced the levels of AG and des-acyl ghrelin and the AG to des-acyl ghrelin ratio. Administration of AG to l-Thy-treated rats reduced cardiac weights and levels of reactive oxygen species and preserved the function and structure of the left ventricle. In addition, AG also reduced the protein levels of cleaved caspase-3 and cytochrome c and prevented mitochondrial permeability transition pore opening. In the left ventricle of both control + AG-treated and l-Thy + AG-treated rats, AG significantly increased left ventricular levels of manganese superoxide dismutase (SOD2), total glutathione (GSH), and Bcl2. It also reduced the levels of malondialdehyde, tumor necrosis factor-α (TNF-α), interleukin-6, and Bax and the nuclear activity of nuclear factor-kappa B. Concomitantly, in both treated groups, AG reduced the mRNA and protein levels of NADPH oxidase 1, angiotensin (Ang) II type 1 receptor, and Ang-converting enzyme 2. All the beneficial effects of AG in l-Thy-treated rats were prevented by the coadministration of [D-Lys3]-GHRP-6, a selective growth hormone secretagogue receptor subtype 1a antagonist. In conclusion, AG protects against hyperthyroidism-induced cardiac hypertrophy and damage, which is mainly due to its antioxidant and anti-inflammatory potentials and requires the activation of GHS-R1a.

Human Milk Metabolic Hormones: Analytical Methods and Current Understanding

Human milk (HM) contains a wide array of peptide hormones including leptin and adiponectin, which are involved in the regulation of infant growth and development. These essential hormones might play an important role in the regulation of metabolic reprogramming of the new-born infant. However, HM hormone studies are sparse and heterogeneous in regard to the study design, sample collection, preparation and analysis methods. This review discussed the limitations of HM hormone analysis highlighting the gaps in pre-analytical and analytical stages. The methods used to quantify HM metabolic hormones (leptin, adiponectin, ghrelin, insulin, obestatin, resistin and apelin) can be classified as immunoassay, immunosensor and chromatography. Immunoassay methods (ELISA and RIA) have been predominantly used in the measurement of these HM hormones. The relative validity parameters of HM hormones analysis are often overlooked in publications, despite the complexity and differences of HM matrix when compared to that of plasma and urine. Therefore, appropriate reports of validation parameters of methodology and instrumentation are crucial for accurate measurements and therefore better understanding of the HM metabolic hormones and their influences on infant outcomes.

Overweight and obesity in type 1 diabetes is not associated with higher ghrelin concentrations

BACKGROUND

Several studies have demonstrated suppressed levels of acylated (AG) and unacylated ghrelin (UAG) in patients with type 2 diabetes. However, the role of these hormones in type 1 diabetes has not been extensively studied. This study assessed the relationship between AG and UAG levels and body composition in patients with type 1 diabetes.

METHODS

We selected eighteen patients with type 1 diabetes and divided them into two groups: non-obese (BMI < 25 kg/m²) and overweight (BMI ≥ 25 kg/m²). Demographics, parameters of body composition and serum parameters including AG and UAG, were assessed.

RESULTS

The patients with a BMI ≥ 25 kg/m² were older and had a longer duration of diabetes. AG and UAG levels were not significantly different between non-obese and overweight groups (mean AG non-obese ± SD: 44.5 ± 29.4 pg/ml and mean UAG non-obese 42.4 ± 20.7 pg/ml vs mean AG overweight ± SD: 46.1 ± 29.6 pg/ml and mean UAG overweight 47.2 ± 18.2 pg/ml). AG/UAG ratios did not discriminate between these groups. There was a positive association of insuline dose/kg bodyweight with BMI (r² = 0.45, p = 0.002).

CONCLUSIONS

Surprisingly, unlike non-diabetics and in T2D, we did not observe a difference in plasma levels of AG and UAG between normal weight and overweight adult type 1 diabetics. However, we did observe a positive correlation between BMI and insuline dose/kg bodyweight, suggesting that exogenous insulin is more important than the ghrelin system in the development of obesity in type 1 diabetes.

Performance and serum parameters of calves (Bos taurus) subject to milk restriction associated with supplementation with 2-hydroxy-4-(methylthio)butanoic acid

Our aim with this study was to evaluate the consumption, performance, quantitative characteristics of carcasses, biochemical profile, plasma levels of ghrelin and leptin, expression of the receptor for ghrelin (GHS-R1a) in the hypothalamus and duodenum, and the number of goblet cells in the duodenum of calves subjected to milk volume restriction and supplemented with 2-hydroxy-4-(methylthio)butanoic acid (HMTBa). We used 21 Holstein mixed-breed calves, aged between 3 and 15 d with an average weight of 36.8 kg, and housed in pens with troughs for hay, concentrate, and water. The study included two consecutive experimental periods (first period [P1] and second period [P2]) of 21 d each, with 7 d of adaptation to the diet and facilities. The calves were distributed in a completely randomized design in three treatments with seven repetitions. 1) Control: 6 liters of milk/d during P1 and 6 liters of milk/day during P2; 2) RES (milk restriction): 3 liters of milk/day during P1 and 6 liters of milk/day during P2; and 3) RES + HMTBa: 3 liters of milk/day during P1 and 6 liters of milk/day during P2 + 3.3 g of HMTBa/day in both periods. HMTBa was supplied in milk, and the amount of concentrated ration and hay provided and leftovers were recorded daily to estimate dry matter (DM) and crude protein consumption. Mean daily weight gain (DWG), final weight (FW), and feed conversion (FC) were obtained at the beginning and at the end of each 21-d period. Plasma concentrations of ghrelin and leptin, triglycerides, total protein, urea, lactate, creatinine, alkaline phosphatase, and cholesterol were measured for P1 and P2 at the end of each 21-d period. At the end of P2, animals were slaughtered; sections of the duodenum were collected to evaluate the expression of GHS-R1a and quantity of goblet cells; hypothalamus was used to evaluate the expression of GHS-R1a; rumen was used to evaluate the thickness of epithelium and keratin and the density, height, and width of ruminal papillae. In P1, total DM consumption, FW, DWG, glucose, and triglycerides were lower in the RES and RES + HMTBa groups (P < 0.001). In P2, there was an improvement in the FC of the RES + HMTBa group (compared with Control and RES groups) and a lower urea concentration in the RES group (compared with Control and RES + HMTBa groups) (P < 0.001). No differences were observed among groups regarding hormonal concentrations, histological parameters, and GHS-R1a expression in the duodenum and hypothalamus. Therefore, milk restriction combined with HMTBa supplementation promoted greater compensatory gain by a mechanism independent of changes in GHS-R1a expression and hormone levels of ghrelin and leptin.

Sleeping patterns and childhood obesity: an epidemiological study in 1,728 children in Greece

STUDY OBJECTIVES

Sleep is an essential normal function for children's growth and development, but over the years, lifestyle changes have resulted in insufficient sleep, a factor that may be associated with increased childhood obesity. The aim of this study was to evaluate the association between sleep duration and sleep patterns separately on weekdays and weekends regarding children's weight status.

METHODS

This study was conducted among Greek students (55.1% girls) in 2014-2016. Children's weight status was classified according to the International Obesity Task Force tables and guidelines. Sleep duration was determined based on the sleep and wake time that children reported, separately for weekdays and weekends. Classification and regression tree analysis was used to derive sleep patterns and evaluate their relation to children's weight status.

RESULTS

Multiadjusted analysis revealed an inverse association between average duration of sleep on weekdays and weekends with the likelihood of being overweight/obese (odds ratio per 1 hour 0.82; 95% confidence interval, 0.73-0.92). This was more prominent on weekends than on weekdays. Children who had lower duration on weekdays, but catch-up sleep duration on weekends, were 2% (95% confidence interval, 0.97-0.99) less likely to be overweight/obese compared to those children having both less or increased sleep duration on weekdays and weekends.

CONCLUSIONS

Sleep duration and sleep patterns seem to be associated with childhood weight status. Interventions should be developed to educate parents on the importance of an adequate sleep duration and healthy sleep patterns for their children's healthy development.

Evaluation the Role of Ghrelin and Leptin as Biochemical Marker in Female with Polycystic Ovarian Syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. PCOS is a heterogeneous complex disorder of unwell defined aetiology. Some studies report its association to various endocrine, metabolic and immunological abnormalities. The hunger hormones ghrelin and leptin affect the pathogenesis of PCOS and might lead to the development of metabolic syndrome (MS) in obese women.

AIM

The study aims at evaluating the role of ghrelin and leptin level in female with poly cystic ovary syndrome as a biochemical marker for the diagnosis and monitoring progression.

SUBJECTS AND METHODS

The study including one hundred PCOS patients and fifty apparently healthy subjects with regular menstrual cycle, visiting gynecology outpatient clinic of Kalar General Hospital, from the beginning of February 2015 to the end of June 2015. Body mass index (BMI) along with serum ghrelin, leptin, Luteinizing hormone (LH), Follicle stimulating hormone (FSH) and testosterone levels were measured for both groups. Serum leptin was determined using sandwich ELISA, while serum ghrelin was determined using competitive ELISA. Differences between patient and control groups were tested by using t-test. Also one way Anova was used to test the relation among different groups.

RESULTS

There was a significant decrease in ghrelin level and increase in leptin levels in women with PCOS when compared with control group. Also there was a significant elevation in serum level of LH ,Testosterone , Prolactin and decrease in serum FSH in PCOS patients when compared to control group. Additionally, serum ghrelin decreased and serum leptin level increased significantly in women with PCOS compared to controls in all age and BMI groups.

CONCLUSION

The significant decrease in ghrelin and increased in leptin in PCOS patients than in controls indicated that they are at high risk for metabolic syndrome development.

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

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

Salmon acyl-ghrelin increases food intake and reduces doxorubicin-induced myocardial apoptosis in rats, likely by anti-oxidative activity

We had reported that orally administered ghrelin-containing salmon stomach extract prevents doxorubicin (DOX)-induced cardiotoxicity. In this study, we investigated the binding affinity of salmon ghrelin to rat ghrelin receptor and the cardioprotective effects of subcutaneous (sc) injected synthetic salmon ghrelin in rats with DOX-induced acute heart failure in order to clarify the potential efficacy of salmon ghrelin. Intracellular calcium mobilization assay was performed on rat GHS-R1a-expressing CHO cells to reveal ghrelin activity. Rats were divided into five groups; the normal control (I), and toxic control (II) groups were given saline (sc, twice daily), and the salmon acyl-ghrelin (sAG) (III), salmon unacylated-ghrelin (sUAG) (IV), and rat acyl-ghrelin (rAG) (V) groups were given corresponding synthetic ghrelins (sc, twice daily), respectively. After seven days of treatment, DOX (20 mg/kg BW) or saline was administered to the corresponding groups by intraperitoneal injection. The toxic control group was the negative control group for the DOX-induced cardiotoxicity groups. While sAG displayed similar affinity to rAG upon application to GHS-R1a-expressing cells, and also decreased DOX-induced apoptosis and increased food intake, sUAG did not. Both sAG and rAG improved DOX-induced deterioration, showing anti-oxidative activity. The anti-oxidative activity of sAG might contribute to the protective effects on cardiomyocytes. The results also suggest that, similar to rAG, sAG is a potent protectant against DOX-induced cardiotoxicity and a potential functional component in orally administered ghrelin-containing salmon stomach extract, which prevented DOX-induced cardiotoxicity in our previous study.

Mice with an RGS-insensitive Gαi2 protein show growth hormone axis dysfunction

Mice carrying an RGS-insensitive Gαi2 mutation display growth retardation early after birth. Although the growth hormone (GH)-axis is a key endocrine modulator of postnatal growth, its functional state in these mice has not been characterized. The present study was undertaken to address this issue. Results revealed that pituitary mRNA levels for GH, prolactin (PRL), somatostatin (SST), GH-releasing-hormone receptor (GHRH-R) and GH secretagogue receptor (GHS-R) were decreased in mutants compared to controls. These changes were reflected by a significant decrease in plasma levels of GH, IGF-1 and IGF-binding protein-3 (IGFBP-3). Mutants were also less responsive to GHRH and ghrelin (GhL) on GH stimulation of release from pituitary primary cell cultures. In contrast, they were more sensitive to the inhibitory effect of SST. These data provide the first evidence for an alteration of the functional state of the GH-axis in Gαi2G184S mice that likely contributes to their growth retardation.

Cooling management effects on dry matter intake, metabolic hormones levels and welfare parameters in dairy cows during heat stress

This research paper addresses the hypothesis that intensive cooling management during the summer improves the secretion of metabolic hormones in dairy cows. To test this hypothesis, we characterized the effect of different cooling managements on the different ghrelin isoforms and leptin secretion of 20 Israeli-Holstein dairy cows during 5 weeks during heat stress. The cows were divided into two groups: one was exposed to 5 cooling sessions per day (5 CS) and the other to 8 cooling sessions per day (8 CS). Blood was collected and leptin and ghrelin isoforms level were radioimmunoassayed. Analysis of the interaction between coolings and the week of the experiment showed that the 8 CS group consumed more food and produced more milk, although neither difference was statistically significant. In addition, the 8 CS group exhibited higher blood levels of acyl-ghrelin and leptin as compared to the 5 CS group. Conversely, the blood levels of total ghrelin were lower in the cows exposed to 8 CS as compared to cows from the 5 CS treatment. Furthermore, a significant correlation was found only between total ghrelin levels and the weeks, but not with other parameters examined. We further compared digestibility as well as stress parameters between the groups. We found that the 8 CS group cows ruminated and lay down more hours during a day and simultaneously had better activity time. No significant difference was detected between groups in milk yield and digestibility parameters. Our results suggest that intensive cooling management during the hot season influences the levels of metabolic hormones in the circulation and helps to mitigate the detrimental effect of heat stress on dairy cow welfare and production.

Gut Microbiota: The Missing Link Between Helicobacter pylori Infection and Metabolic Disorders?

Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. Although the majority of infected individuals remain asymptomatic, this bacterium colonizes the gastric mucosa causing the development of various clinical conditions as peptic ulcers, chronic gastritis and gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas, but complications are not limited to gastric ones. Extradigestive pathologies, including metabolic disturbances such as diabetes, obesity and nonalcoholic fatty liver disease, have also been associated with H. pylori infection. However, the underlying mechanisms connecting H. pylori with extragastric metabolic diseases needs to be clarified. Notably, the latest studies on the topic have confirmed that H. pylori infection modulates gut microbiota in humans. Damage in the gut bacterial community (dysbiosis) has been widely related to metabolic dysregulation by affecting adiposity, host energy balance, carbohydrate metabolism, and hormonal modulation, among others. Taking into account that Type 2 diabetic patients are more prone to be H. pylori positive, gut microbiota emerges as putative key factor responsible for this interaction. In this regard, the therapy of choice for H. pylori eradication, based on proton pump inhibitor combined with two or more antibiotics, also alters gut microbiota composition, but consequences on metabolic health of the patients has been scarcely explored. Recent studies from our group showed that, despite decreasing gut bacterial diversity, conventional H. pylori eradication therapy is related to positive changes in glucose and lipid profiles. The mechanistic insights explaining these effects should also be addressed in future research. This review will deal with the role of gut microbiota as the linking factor between H. pylori infection and metabolic diseases, and discussed the impact that gut bacterial modulation by H. pylori eradication treatment can also have in host's metabolism. For this purpose, new evidence from the latest human studies published in more recent years will be analyzed.

LEAP-2: An Emerging Endogenous Ghrelin Receptor Antagonist in the Pathophysiology of Obesity

Liver-expressed antimicrobial peptide 2 (LEAP-2), originally described as an antimicrobial peptide, has recently been recognized as an endogenous blocker of growth hormone secretagogue receptor 1a (GHS-R1a). GHS-R1a, also known as ghrelin receptor, is a G protein-coupled receptor (GPCR) widely distributed on the hypothalamus and pituitary gland where it exerts its major functions of regulating appetite and growth hormone (GH) secretion. The activity of GHS-R1a is controlled by two counter-regulatory endogenous ligands: Ghrelin (activation) and LEAP-2 (inhibition). Ghrelin activates GHS-R1a on the neuropeptide Y/Agouti-related protein (NPY/AgRP) neurons at the arcuate nucleus (ARC) to promote appetite, and on the pituitary somatotrophs to stimulate GH release. On the flip side, LEAP-2, acts both as an endogenous competitive antagonist of ghrelin and an inverse agonist of constitutive GHS-R1a activity. Such a biological property of LEAP-2 vigorously blocks ghrelin's effects on food intake and hormonal secretion. In circulation, LEAP-2 displays an inverse pattern as to ghrelin; it increases with food intake and obesity (positive energy balance), whereas decreases upon fasting and weight loss (negative energy balance). Thus, the LEAP-2/ghrelin molar ratio fluctuates in response to energy status and modulation of this ratio conversely influences energy intake. Inhibiting ghrelin's activity has shown beneficial effects on obesity in preclinical experiments, which sheds light on LEAP-2's anti-obesity potential. In this review, we will analyze LEAP-2's effects from a metabolic point of view with a focus on metabolic hormones (e.g., ghrelin, GH, and insulin), and discuss LEAP-2's potential as a promising therapeutic target for obesity.

The Relationship Between Food Craving, Appetite-Related Hormones and Clinical Parameters in Bipolar Disorder

Obesity and weight gain in bipolar disorder (BD) have multifactorial underlying causes such as medication side effects, atypical depressive symptomatology, genetic variants, and disturbances in the neuro-endocrinal system. Therefore, we aim to explore the associations between food craving (FC), clinical parameters, psychotropic medication, and appetite-related hormones. In this cross-sectional investigation, 139 individuals with BD and 93 healthy controls (HC) completed the food craving inventory (FCI). In addition, blood samples (including leptin and acylated ghrelin) were analyzed and sociodemographic and anthropometric data were collected. Individuals with BD reported higher frequencies of total FC as well as craving for fat and fast food than HC. Additionally, we found a significant negative correlation between FC and ghrelin levels in BD. Smokers with BD reported significantly more craving for high fat foods than non-smokers. Age was significantly associated with FC independent of group. Individuals with BD taking olanzapine and quetiapine reported higher frequencies of craving for sweet food, while patients currently taking lithium reported less total FC compared to those without lithium therapy. Likewise, patients currently taking valproate reported less total FC and less craving for sweets than those not taking valproate. FC appears to be of clinical relevance in individuals with BD. Contrary to previous data, this does not seem to be a female phenomenon only and might encompass more than the specific craving for carbohydrates. Although due to the cross sectional design, causality cannot be determined, the association between depressive symptomatology and fast food craving warrants further research.