Differential influences of gastric bypass and sleeve gastrectomy on plasma nesfatin-1 and obestatin levels in patients with type 2 diabetes mellitus

State of art on the mechanisms of laparoscopic sleeve gastrectomy in treating type 2 diabetes mellitus

Obesity and type-2 diabetes mellitus (T2DM) are metabolic disorders. Obesity increases the risk of T2DM, and as obesity is becoming increasingly common, more individuals suffer from T2DM, which poses a considerable burden on health systems. Traditionally, pharmaceutical therapy together with lifestyle changes is used to treat obesity and T2DM to decrease the incidence of comorbidities and all-cause mortality and to increase life expectancy. Bariatric surgery is increasingly replacing other forms of treatment of morbid obesity, especially in patients with refractory obesity, owing to its many benefits including good long-term outcomes and almost no weight regain. The bariatric surgery options have markedly changed recently, and laparoscopic sleeve gastrectomy (LSG) is gradually gaining popularity. LSG has become an effective and safe treatment for type-2 diabetes and morbid obesity, with a high cost-benefit ratio. Here, we review the me-chanism associated with LSG treatment of T2DM, and we discuss clinical studies and animal experiments with regard to gastrointestinal hormones, gut microbiota, bile acids, and adipokines to clarify current treatment modalities for patients with obesity and T2DM.

Does NUCB2/Nesfatin-1 Influence Eating Behaviors in Obese Patients with Binge Eating Disorder? Toward a Neurobiological Pathway

Nesfatin-1 is a new anorexigenic neuropeptide involved in the regulation of hunger/satiety, eating, and affective disorders. We aimed to investigate nesfatin-1 secretion in vitro, in murine adipose cells, and in human adipose fat samples, as well as to assess the link between circulating nesfatin-1 levels, NUCB2 and Fat Mass and Obesity Gene (FTO) polymorphisms, BMI, Eating Disorders (EDs), and pathological behaviors. Nesfatin-1 secretion was evaluated both in normoxic fully differentiated 3T3-L1 mouse adipocytes and after incubation under hypoxic conditions for 24 h. Omental Visceral Adipose tissue (VAT) specimens of 11 obese subjects, and nesfatin-1 serum levels' evaluation, eating behaviors, NUCB2 rs757081, and FTO rs9939609 polymorphisms of 71 outpatients seeking treatment for EDs with different Body Mass Index (BMI) were studied. Significantly higher levels of nesfatin-1 were detected in hypoxic 3T3-L1 cultured adipocytes compared to normoxic ones. Nesfatin-1 was highly detectable in the VAT of obese compared to normal-weight subjects. Nesfatin-1 serum levels did not vary according to BMI, sex, and EDs diagnosis, but correlations with grazing; emotional, sweet, and binge eating; hyperphagia; social eating; childhood obesity were evident. Obese subjects with CG genotype NUCB2 rs757081 and AT genotype FTO rs9939609 polymorphisms had higher nesfatin-1 levels. It could represent a new biomarker of EDs comorbidity among obese patients.

NUCB2/nesfatin-1 is associated with severity of eating disorder symptoms in female patients with obesity

BACKGROUND

Nesfatin-1 has been described as an anorexigenic peptide. Comprehensive evidence also points towards an involvement of nesfatin-1 in the modulation of emotional pathways with a sex-specific regulation of nesfatin-1 in association with anxiety. Although the implication of nesfatin-1 in the regulation of food intake is well-established in animals, data in humans are lacking. Therefore, we investigated a possible association of circulating NUCB2/nesfatin-1 with eating disorder symptoms in female and male patients displaying a wide range of body weight.

METHODS

We enrolled 243 inpatients (177 female, 66 male) hospitalized due to anorexia nervosa (n = 66) or obesity (n = 144) or with normal weight and suffering from somatoform, adjustment, depressive or anxiety disorders (n = 33). Plasma samples (NUCB2/nesfatin-1 levels measured by ELISA) and measures of eating disorder symptoms (by EDI-2, range 0-100) were obtained within three days after admission.

RESULTS

The study population displayed a distinct prevalence of eating disorder symptoms with female patients with anorexia nervosa (+ 77.0%, p < 0.001) and obesity (+ 87.9%, p < 0.001) reported significantly higher EDI-2 scores than normal weight patients of the same sex. Accordingly, males with anorexia nervosa (+ 39.7%, p < 0.05) and obesity (+ 51.7%, p < 0.001) had significantly higher EDI-2 scores than males with normal weight. Within the same BMI group, women displayed significantly higher scores than men (+ 21.4%, p < 0.05 in patients with anorexia nervosa, + 18.8%, p < 0.001 in participants with obesity). We observed a positive correlation between NUCB2/nesfatin-1 levels and EDI-2 total scores in female patients with obesity (r = 0.285, p = 0.015), whereas no associations were found in other subgroups. A positive correlation between NUCB2/nesfatin-1 levels and BMI was only observed in the male study population (r = 0.315, p = 0.018).

CONCLUSIONS

NUCB2/nesfatin-1 plasma levels were positively associated with EDI-2 total scores in women with obesity, while no association was observable in men. The lacking association of NUCB2/nesfatin-1 and EDI-2 total scores in female patients with anorexia nervosa might be due to already low NUCB2/nesfatin-1 plasma levels. Whether NUCB2/nesfatin-1 is selectively involved in eating behavior in women with obesity will have to be further investigated.

Neurohormonal Changes in the Gut–Brain Axis and Underlying Neuroendocrine Mechanisms following Bariatric Surgery

Obesity is a complex, multifactorial disease that is a major public health issue worldwide. Currently approved anti-obesity medications and lifestyle interventions lack the efficacy and durability needed to combat obesity, especially in individuals with more severe forms or coexisting metabolic disorders, such as poorly controlled type 2 diabetes. Bariatric surgery is considered an effective therapeutic modality with sustained weight loss and metabolic benefits. Numerous genetic and environmental factors have been associated with the pathogenesis of obesity, while cumulative evidence has highlighted the gut–brain axis as a complex bidirectional communication axis that plays a crucial role in energy homeostasis. This has led to increased research on the roles of neuroendocrine signaling pathways and various gastrointestinal peptides as key mediators of the beneficial effects following weight-loss surgery. The accumulate evidence suggests that the development of gut-peptide-based agents can mimic the effects of bariatric surgery and thus is a highly promising treatment strategy that could be explored in future research. This article aims to elucidate the potential underlying neuroendocrine mechanisms of the gut–brain axis and comprehensively review the observed changes of gut hormones associated with bariatric surgery. Moreover, the emerging role of post-bariatric gut microbiota modulation is briefly discussed.

Inflammatory mechanisms linking obesity and tendinopathy

Chronic tendinopathy is a debilitating tendon disorder with disappointing treatment outcomes. This review focuses on the potential roles of chronic low-grade inflammation in promoting tendinopathy in obesity. A systematic literature search was performed to identify all clinical studies supporting the actions of obesity-associated inflammatory mediators in the development of tendinopathy. The mechanisms of obesity-induced chronic inflammation in adipose tissue are firstly reviewed. Common inflammatory mediators potentially linking obesity and the development of tendinopathy, and their association with mechanical overuse, are discussed, along with pre-clinical evidences and a systematic literature search on clinical studies. The potential contribution of local adipose tissues in the promotion of inflammation, pain and tendon degeneration is then discussed. The future research directions are proposed.

Translational potential statement

Better understanding of the roles of obesity-associated inflammatory mediators on tendons will clarify the pathophysiological drivers of tendinopathy in patients with obesity and identify possible treatment targets. Further studies on the mechanisms of obesity-induced chronic inflammation on tendon are a promising direction for the treatment of tendinopathy.

Neuroendocrine Peptides of the Gut and Their Role in the Regulation of Food Intake

The regulation of food intake encompasses complex interplays between the gut and the brain. Among them, the gastrointestinal tract releases different peptides that communicate the metabolic state to specific nuclei in the hindbrain and the hypothalamus. The present overview gives emphasis on seven peptides that are produced by and secreted from specialized enteroendocrine cells along the gastrointestinal tract in relation with the nutritional status. These established modulators of feeding are ghrelin and nesfatin-1 secreted from gastric X/A-like cells, cholecystokinin (CCK) secreted from duodenal I-cells, glucagon-like peptide 1 (GLP-1), oxyntomodulin, and peptide YY (PYY) secreted from intestinal L-cells and uroguanylin (UGN) released from enterochromaffin (EC) cells. © 2021 American Physiological Society. Compr Physiol 11:1679-1730, 2021.

Alterations in Small Intestine and Liver Morphology, Immunolocalization of Leptin, Ghrelin and Nesfatin-1 as Well as Immunoexpression of Tight Junction Proteins in Intestinal Mucosa after Gastrectomy in Rat Model

The stomach is responsible for the processing of nutrients as well as for the secretion of various hormones which are involved in many activities throughout the gastrointestinal tract. Experimental adult male Wistar rats (n = 6) underwent a modified gastrectomy, while control rats (n = 6) were sham-operated. After six weeks, changes in small intestine (including histomorphometrical parameters of the enteric nervous plexuses) and liver morphology, immunolocalization of leptin, ghrelin and nesfatin-1 as well as proteins forming adherens and tight junctions (E-cadherin, zonula occludens-1, occludin, marvelD3) in intestinal mucosa were evaluated. A number of effects on small intestine morphology, enteric nervous system ganglia, hormones and proteins expression were found, showing intestinal enteroplasticity and neuroplasticity associated with changes in gastrointestinal tract condition. The functional changes in intestinal mucosa and the enteric nervous system could be responsible for the altered intestinal barrier and hormonal responses following gastrectomy. The results suggest that more complicated regulatory mechanisms than that of compensatory mucosal hypertrophy alone are involved.

NUCB2/nesfatin-1 - Inhibitory effects on food intake, body weight and metabolism

Since its discovery in 2006 by Oh-I and colleagues, NUCB2/nesfatin-1 encoded by nucleobindin-2 (NUCB2) has drawn sustained attention as reflected in over 500 publications. Among those, more than half focused on the alterations of food intake, body weight and metabolism (glucose, fat) induced by nesfatin-1 and/or NUCB2/nesfatin-1. In the current review we discuss the existing literature focusing on NUCB2/nesfatin-1's influence on food intake, body weight and glucose as well as fat metabolism and highlight gaps in knowledge.

Current status of endoscopic sleeve gastroplasty: An opinion review

Bariatric surgeries have been demonstrated to be safe and effective treatment options for morbid obesity patients, but operative risks and high health care costs limit their clinical application. Endoscopic bariatric therapies are emerging as valuable alternatives for patients with doubts about bariatric surgery or ineligible for it. Endoscopic sleeve gastroplasty (ESG), a relatively novel technique of endoscopic bariatric therapies, has gained standing in the past few years. The safety, feasibility, repeatability, and potential for reversibility of ESG have been proven by multicenter studies. Compared to other weight loss strategies, current evidence demonstrates that ESG offers satisfactory efficacy in weight loss. Even though it is inferior to laparoscopic sleeve gastrectomy, it has lower risks of adverse events than surgical interventions and intragastric balloon within one-year follow-up. Furthermore, ESG may be the ideal weight control strategy for patients who have poor adherence to behavioral interventions. Even so, trends in decreased weight loss effect over time, post-procedure weight regain, post-procedure gut hormone alteration, and possible effects of race and ethnicity on ESG still remain undetermined due to very limited reports and very short follow-ups. Further clinical trials are required to validate and answer these questions.

Changes in Serum Nesfatin-1 After Laparoscopic Sleeve Gastrectomy are Associated with Improvements in Nonalcoholic Fatty Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a serious and widespread disease worldwide. Bariatric surgery is one of the treatments for NAFLD. Nesfatin-1 is located in the brain, periphery and plasma. We studied the relationship between nesfatin-1 changes after laparoscopic sleeve gastrectomy (LSG) and NAFLD remission.

METHODS

A total of 29 patients participated in the study, which collected clinical information on the patients and indicators of liver function, hepatic steatosis score and nesfatin-1 level before and after LSG.

RESULTS

The average BMI of the patients before surgery was 42.63±8.91 kg/m², and the average BMI was 28.54±5.63 kg/m² one year after surgery (p < 0.05). One year after LSG, the total weight loss percentage (TWL%) was 32.11±7.10%. The mean value of nesfatin-1 before surgery was 3.04±0.81 ng/mL, and the mean value of nesfatin-1 was 5.52±1.55 ng/mL at one year after surgery (p < 0.05). The average preoperative hepatic steatosis index (HSI) score of the patients was 52.55±9.17, and the average postoperative HSI score was 38.84±5.82 (p < 0.05). Before LSG (p < 0.05, r= -0.81) and 1 year after surgery (p < 0.05, r = -0.58), HSI and nesfatin-1 were significantly negatively correlated. Percentage of increased nesfatin-1 and percentage of decreased HSI showed positive correlation after LSG.

CONCLUSION

There was a negative correlation between HSI and nesfatin-1 before and after LSG, which may suggest that nesfatin-1 plays a role in NAFLD.

The influence of bariatric surgery on serum levels of irisin and nesfatin-1

Introduction: Bariatric surgery is associated with multiple endocrine and metabolic changes. Irisin and nesfatin-1 have recently been described as regulatory peptides involved in obesity-related insulin resistance. Our aim was to analyze the changes of those two molecules observed in patients after bariatric procedures. Materials and methods: This prospective study involved 40 patients treated for morbid obesity. Irisin and nesfatin-1 were measured before, 6 months and 1 year after surgical intervention. We also gathered demographic data, information concerning comorbidities, factors related to the surgery and outcomes of bariatric treatment. Results: Twenty-seven patients completed the study (15 females). The mean age of the group was 43.5 ± 10.4 years. Six (22.2%) patients were submitted to Laparoscopic Sleeve Gastrectomy and 21 (77.8%) patients were submitted to Laparoscopic Roux-en-Y Gastric Bypass. The participants in our study achieved significant weight loss. The irisin level remained stable in the whole study group during all three measurements included in our study protocol (p = .71). Our study group presented a reduction of the nesfatin-1 level 6 months after bariatric surgery and a slight further decrease after one-year observation, although these changes were also not significant (p = .17). Conclusions: We did not find any significant correlation between changes of irisin or nesfatin-1 level and bariatric surgery, as an aid in the regulation of glucose metabolism.

Sex-specific association of plasma nesfatin-1 concentrations with obesity in children

BACKGROUND

Nesfatin-1, an anorexigenic peptide, has been associated with food intake and thermogenesis, with discordant findings in humans and scarce studies in children to date.

OBJECTIVES

The aim of this study was to analyze the relationship of obesity with nesfatin-1 levels in two cohorts of children.

METHODS

Plasma nesfatin-1 concentrations were analyzed in 6- to 9-year-olds (n = 140) and 12- to 16-year-old children (n = 96), including children with obesity and their sex- and age-matched normal-weight counterparts. Anthropometric measurements were assessed. Cholesterol and triglycerides were determined enzymatically, insulin concentrations were measured by radioimmunoassay using a commercial kit and nesfatin-1, leptin and hs-CRP concentrations were determined using commercial ELISA kits.

RESULTS

Nesfatin-1 concentrations were significantly lower in younger (P = .001) and older (P = .009) girls with obesity than in their normal-weight counterparts, without showing significant differences in boys. Nesfatin-1 showed a negative significant (P < .010) correlation with weight and BMI in girls but not in boys. A significant positive correlation of nesfatin-1 levels with insulin, HOMA, and leptin levels appears in girls after adjusting by age and BMI. A significant positive correlation (P = .003) was observed between nesfatin-1 and fat mass in older children.

CONCLUSIONS

Our study shows lower concentrations of nesfatin-1 related to obesity in girls but not in boys at two different ages. The existence of a sex-specific association between nesfatin-1 concentrations and presence of obesity highlights the need of an analysis by gender of the relationship of nesfatin-1 with obesity.

Hypothalamic nesfatin-1 mediates feeding behavior via MC3/4R-ERK signaling pathway after weight loss in obese Sprague-Dawley rats

Nesfatin-1 is an anorexic peptide derived from nucleobindin 2 (NUCB2). An increase in hypothalamic nesfatin-1 inhibits feeding behavior and promotes weight loss. However, the effects of weight loss on hypothalamic nesfatin-1 levels are unclear. In this study, obese rats lost weight in three ways: Calorie Restriction diet (CRD), Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB). We found an increase in nesfatin-1 serum and cerebrospinal fluid levels after weight loss in obese Sprague-Dawley (SD) rats. Moreover, weight loss also increased hypothalamic melanocortin 3/4 receptor (MC3/4R) and extracellular regulated kinase phosphorylation (p-ERK) signaling. Third ventricle administration of antisense morpholino oligonucleotide (MON) against the gene encoding NUCB2 inhibited hypothalamic nesfatin-1 and p-ERK signaling, increased food intake and reduced body weight loss in SG and RYGB obese rats. Third ventricle administration of SHU9119 (MC3/4R blocker) blocked hypothalamic MC3/4R, inhibited p-ERK signaling, increased food intake and reduced body weight loss in SG and RYGB obese rats. These findings indicate that weight loss leads to an increase in hypothalamic nesfatin-1. The increase in hypothalamic nesfatin-1 participates in regulating feeding behavior through the MC3/4R-ERK signaling especially after SG and RYGB.

SERUM NESFATIN-1 LEVEL IN HEALTHY SUBJECTS WITH WEIGHT-RELATED ABNORMALITIES AND NEWLY DIAGNOSED PATIENTS WITH TYPE 2 DIABETES MELLITUS; A CASE-CONTROL STUDY

Context

Nesfatin-1 is a novel peptide with both central and peripheral anorexigenic regulatory properties. Besides its effects on food intake, few studies have suggested a possible role for this peptide in the pathogenesis of diabetes mellitus type 2.

Objective

To compare serum levels of nesfatin-1 between healthy, normal-weight persons and three groups including healthy underweight, healthy obese and diabetic subjects.

Design

Prospective, case-control study, performed between January 2015 and January 2016.

Subjects and Methods

Fasting levels in serum nesfatin-1 were measured in 30 healthy, normal-weight individuals (controls), 30 healthy underweight persons, 30 healthy obese persons, and 30 patients with newly diagnosed diabetes type 2 using standard enzyme-linked immunosorbent assay (ELISA) kits.

Results

The mean serum nesfatin-1 level was significantly higher in controls (2.61 ng/mL) compared to that in obese (1.13 ng/mL) and diabetic (0.99 ng/mL) patients; and significantly lower than that in the underweight group (3.50 ng/mL). The obese and diabetic groups were comparable in this regard. No significant association was found between serum nesfatin-1 level and age, sex, or body mass index.

Conclusions

Serum nesfatin-1 is possibly associated with weight-related abnormalities in otherwise healthy subjects and diabetes type 2. Obesity and diabetes type 2 may share a common pathologic point in this regard.

Current Understanding of the Role of Nesfatin-1

Nesfatin-1 was discovered in 2006 and implicated in the regulation of food intake. Subsequently, its widespread central and peripheral distribution gave rise to additional effects. Indeed, a multitude of actions were described, including modulation of gastrointestinal functions, glucose and lipid metabolism, thermogenesis, mediation of anxiety and depression, as well as cardiovascular and reproductive functions. Recent years have witnessed a great increase in our knowledge of these effects and their underlying mechanisms, which will be discussed in the present review. Lastly, gaps in knowledge will be highlighted to foster further studies.

Biochemical properties and biological actions of obestatin and its relevence in type 2 diabetes

Obestatin was initially discovered in rat stomach extract, and although it is principally produced in the gastric mucosa, it can be found throughout the gastrointestinal tract. This 23-amino acid C-terminally amidated peptide is derived from preproghrelin and has been ascribed a wide range of metabolic effects relevant to type 2 diabetes. Obestatin reportedly inhibits gastrointestinal motility, reduces food intake and lowers body weight and improves lipid metabolism. Furthermore, it appears to exert actions on the pancreatic β-cell, most notably increasing β-cell mass and upregulating genes associated with insulin production and β-cell regeneration, with relevance to type 2 diabetes. It is becoming evident that obestatin also exerts pleiotropic effects on the cardiovascular system, possibly modulating blood pressure, endothelial function and triggering cardioprotective mechanisms, which may be important in determining cardiovascular outcomes in type 2 diabetes. Furthermore, it seems that like other gut peptides obestatin has neuroprotective properties. This review examines the biochemical properties of the obestatin peptide (its structure, sequence, stability and distribution) and the candidate receptors through which it may act. It provides a balanced examination of the reported pancreatic and extrapancreatic actions of obestatin and evaluates its potential relevance with respect to diabetes therapy, together with discussion of direct evidence linking alterations in obestatin signalling with obesity/diabetes and other diseases.

Alterations of circulating NUCB2/nesfatin-1 during short term therapeutic improvement of anxiety in obese inpatients

In addition to its anorexigenic properties in the neuroendocrine regulation of hunger and satiety, mounting evidence indicates a role for NUCB2/nesfatin-1 in the regulation of emotional stress responses which seems to occur in a sex-specific way. In the present study, we investigated the association of NUCB2/nesfatin-1 plasma levels with anxiety, depressiveness and perceived stress in obese men and women and their alterations during inpatient treatment. We expected a decrease of NUCB2/nesfatin-1 levels in female and an increase in male patients reporting a relevant alleviation of anxiety. We analyzed 69 inpatients (44 female, 25 male; body mass index, mean: 50.2±9.5kg/m², range: 31.8-76.5kg/m²; mean age: 45.0±12.4years) hospitalized due to morbid obesity with mental (not necessarily anxiety disorders) and somatic comorbidities. NUCB2/nesfatin-1 plasma levels were measured by ELISA. Anxiety (GAD-7), depressiveness (PHQ-9) and perceived stress (PSQ-20) were concurrently determined as patient-reported outcomes. All measurements were carried out at the initiation of and during inpatient treatment when a clinically meaningful improvement of anxiety was achieved (≥5 points on GAD-7) or missed (±1 point). NUCB2/nesfatin-1 was positively correlated with anxiety scores in women at the beginning of (r=0.411; p=0.006) and during (r=0.301; p=0.047) inpatient treatment. In men, a significant negative correlation was observed following treatment (r=-0.469; p=0.018), while at the outset of treatment only a trend was observed (r=-0.381; p=0.059). Unexpectedly, neither women (n=19; at beginning vs. during treatment; 0.49±1.00ng/ml vs. 0.38±0.72ng/ml; p=0.687) nor men (n=9; 0.17±0.31ng/ml vs. 0.19±0.36ng/ml; p=0.427) who improved in anxiety scores (p<0.001) displayed significant changes of NUCB2/nesfatin-1 plasma levels, although the direction of change was as expected with a decrease in women (-23.3%) and an increase in men (+12.4%). In addition, the change of NUCB2/nesfatin-1 was not explained by the course of anxiety (women: p=0.587; men: p=0.373). In conclusion, women and men showed an inverse association between NUCB2/nesfatin-1 and anxiety with a positive correlation in women and a negative correlation in men (although this correlation was not statistically significant in men at the beginning of treatment). However, no significant change of NUCB2/nesfatin-1 following improvement of anxiety has been observed. This might be due to the short observation interval, or due to too small anxiety improvements associated with too low baseline anxiety levels.

Vascular Effects of Obestatin in Lean and Obese Subjects

Obese patients have impaired vasodilator reactivity and increased endothelin 1 (ET-1)-mediated vasoconstriction, two abnormalities contributing to vascular dysfunction. Obestatin, a product of the ghrelin gene, in addition to favorable effects on glucose and lipid metabolism, has shown nitric oxide (NO)-dependent vasodilator properties in experimental models. Given these premises, we compared the effects of exogenous obestatin on forearm flow in lean and obese subjects and assessed its influence on ET-1-dependent vasoconstrictor tone in obesity. In both lean and obese participants, infusion of escalating doses of obestatin resulted in a progressive increase in blood flow from baseline (both P < 0.001). This vasodilation was predominantly mediated by enhanced NO activity, because N^G-monomethyl-l-arginine markedly blunted the flow response to obestatin in both groups (both P < 0.05 vs. saline). In obese subjects, antagonism of ET_A receptors by BQ-123 increased forearm flow during saline (P < 0.001) but did not induce additional vasodilation (P > 0.05) during obestatin. Circulating obestatin levels were not different between lean and obese participants (P = 0.41). Our findings indicate that obestatin causes NO-dependent vasodilation in the human circulation. This effect is preserved in obesity, where it is accompanied by reduced ET-1-mediated vasoconstriction. These latter observations make obestatin a promising target for vascular prevention in obesity and diabetes.

Control of Food Intake by Gastrointestinal Peptides: Mechanisms of Action and Possible Modulation in the Treatment of Obesity

This review focuses on the control of appetite by food intake-regulatory peptides secreted from the gastrointestinal tract, namely cholecystokinin, glucagon-like peptide 1, peptide YY, ghrelin, and the recently discovered nesfatin-1 via the gut-brain axis. Additionally, we describe the impact of external factors such as intake of different nutrients or stress on the secretion of gastrointestinal peptides. Finally, we highlight possible conservative—physical activity and pharmacotherapy—treatment strategies for obesity as well as surgical techniques such as deep brain stimulation and bariatric surgery also altering these peptidergic pathways.

Relation of serum and vitreous nesfatin-1 concentrations with diabetic retinopathy

OBJECTIVE

Nesfatin-1, belonging to adipokine family, serves as an anti-inflammatory mediator. We performed this investigation to evaluate the relation between serum and vitreous nesfatin-1 concentrations with diabetic retinopathy (DR).

METHODS

This study was performed in a population of 189 diabetic patients and 48 control subjects. Diabetic patients were then divided into diabetic patients without DR, non-proliferative diabetic retinopathy (NPDR) patients, and proliferative diabetic retinopathy (PDR) patients.

RESULTS

Serum and vitreous nesfatin-1 concentrations were significantly lower in the diabetic patients than in the controls. NPDR patients had reduced vitreous nesfatin-1 concentrations compared with patients without DR. In addition, there were significantly lower serum and vitreous nesfatin-1 concentrations in PDR patients compared with the other three groups. Pearson correlation analysis showed that serum nesfatin-1 was negatively correlated with body mass index and fasting plasma glucose in diabetic patients.

CONCLUSION

Serum and vitreous nesfatin-1 concentrations were negatively correlated with DR.

Association between nesfatin-1 levels and metabolic improvements in severely obese patients who underwent biliopancreatic derivation with duodenal switch

CONTEXT

Nesfatin-1 is a neuroendocrine peptide with potent anorexigenic activity in rodents. The potential role of nesfatin-1 on the regulation of energy balance, metabolic functions and inflammation is currently debated in obese humans. In the present study, nesfatin-1 fluctuations and their associations with metabolic factors were investigated in severely obese patients who underwent biliopancreatic diversion with duodenal switch (BPD/DS) and severely obese controls (SOC).

BASIC PROCEDURES

Sixty severely obese patients who underwent BPD/DS and 15 SOC (matched for BMI and age) were included in the study. Associations between nesfatin-1 levels and body composition, glucose metabolism, lipid profile as well as inflammatory markers were evaluated at baseline and over a post-surgery12-month (12M) period.

MAIN FINDINGS

Body weight was reduced at 6M and at 12M in BPD/DS patients (P<0.001). Nesfatin-1 levels were reduced at 6M (women: P<0.05) and at 12M (men and women; P<0.001) in BPD/DS patients. At baseline, nesfatin-1 levels negatively correlated with weight, fat (FM) and fat-free mass (FFM) in the whole population (combined BPD/DS and SOC patients). At 12M, nesfatin-1 concentrations positively correlated with weight, FM, fasting insulin, insulin resistance, total cholesterol, LDL-cholesterol, triglyceride and apoB values. At 12M, % changes in nesfatin-1 were positively associated with% changes in weight, FM, FFM, fasting insulin, insulin resistance, total cholesterol, LDL-cholesterol, apoB and C-reactive protein.

CONCLUSION

Nesfatin-1 levels decrease following BPD/DS-induced weight loss and are significantly associated with parameters of metabolic health.

The role of obestatin in roux-en-Y gastric bypass-induced remission of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a complex and multifactorial disease that is generally characterized by insulin resistance and loss of β-cell function that develops in adulthood. To date, more than 6% of the world's population is affected by T2DM. The main treatments of T2DM are dietary and lifestyle changes. However, only dependent on behaviour modification and oral hypoglycemics, many patients are unable to maintain glycemic control. Emerging evidence indicates that up to 80% of patients with T2DM undergoing Roux-en-Y gastric bypass (RYGB) experience complete remission of their T2DM and the majority of remissions occur almost immediately following the operation. Obestatin is a 23-amino-acid peptide, which is not only thought to suppress food intake and decrease gastric emptying but also found to exert survival effects in pancreatic β cells, increase glucose-stimulated insulin secretion, and reduce insulin resistance and inflammation. In addition, some researchers demonstrated that obestatin is a nutritional marker reflecting body adiposity and insulin resistance. Although results from previous studies were conflicting, the peripheral blood concentrations of obestatin were changed after RYGB. Therefore, regulation of obestatin level may be another mechanism for RYGB-induced remission of T2DM. In this article, we review briefly the effect of RYGB on T2DM in humans and offer an overview of the published data on the effects of RYGB on obestatin level in patients with T2DM. Furthermore, the possible roles of obestatin in the remission of T2DM following RYGB are also reviewed. Copyright © 2015 John Wiley & Sons, Ltd.

Laparoscopic Roux-en-Y Gastric Bypass Versus Laparoscopic Sleeve Gastrectomy to Treat Morbid Obesity-Related Comorbidities: a Systematic Review and Meta-analysis

Our aim was to compare laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) for treating morbid obesity and its related comorbidities. An electronic literature search was performed from inception to May 2015 and a total of 18,455 patients, enrolled in 62 recent studies, were included in this meta-analysis. Patients receiving LRYGB had a significantly higher percentage of excess weight loss and better resolution of hypertension, dyslipidemia, gastroesophageal reflux disease, and arthritis compared with those receiving LSG. LRYGB and LSG showed similar effects on type 2 diabetes mellitus and sleep apnea.

Obestatin as a key regulator of metabolism and cardiovascular function with emerging therapeutic potential for diabetes

Obestatin is a 23-amino acid C-terminally amidated gastrointestinal peptide derived from preproghrelin and which forms an α helix. Although obestatin has a short biological half-life and is rapidly degraded, it is proposed to exert wide-ranging pathophysiological actions. Whilst the precise nature of many of its effects is unclear, accumulating evidence supports positive actions on both metabolism and cardiovascular function. For example, obestatin has been reported to inhibit food and water intake, body weight gain and gastrointestinal motility and also to mediate promotion of cell survival and prevention of apoptosis. Obestatin-induced increases in beta cell mass, enhanced adipogenesis and improved lipid metabolism have been noted along with up-regulation of genes associated with beta cell regeneration, insulin production and adipogenesis. Furthermore, human circulating obestatin levels generally demonstrate an inverse association with obesity and diabetes, whilst the peptide has been shown to confer protective metabolic effects in experimental diabetes, suggesting that it may hold therapeutic potential in this setting. Obestatin also appears to be involved in blood pressure regulation and to exert beneficial effects on endothelial function, with experimental studies indicating that it may also promote cardioprotective actions against, for example, ischaemia-reperfusion injury. This review will present a critical appraisal of the expanding obestatin research area and discuss the emerging therapeutic potential of this peptide for both metabolic and cardiovascular complications of diabetes.

Comparison of gut hormones and adipokines stimulated by glucagon test among patients with type II diabetes mellitus after metabolic surgery

Laparoscopic Roux-en-Y gastric bypass (RYGB) achieves a higher remission of type 2 diabetes mellitus (T2DM) than laparoscopic sleeve gastrectomy (SG) in non-morbidly obese patients. However, the mechanisms of the higher remission are unknown. To compare glucagon-provoked acute insulin responses, as well as changes of gut and pancreatic hormones and adipokines between patients with T2DM after RYGB and SG at one year post-operatively, a total of 14 RYGB and 13 SG patients were followed-up and evaluated for glucose metabolism, gut and pancreatic hormones, and adipokines. One year after surgery, 1-mg intravenous glucagon tests were performed. The differences in each hormone at different time points and the area under the curve (AUC) were compared between the two groups. Glucagon-stimulated acute insulin responses were not different between the RYGB and SG groups, nor were they different between the remitters and non-remitters at one year after the metabolic surgery. Plasma des-acyl ghrelin and nesfatin-1 levels significantly decreased at 6 min after glucagon stimulation in the RYGB and SG groups, as well as in the remitters and non-remitters. The glucagon test did not affect intestinal hormones. Plasma resistin was suppressed after intravenous glucagon stimulation in both RYGB and SG groups. In conclusion, intravenous glucagon inhibited plasma levels of des-acyl ghrelin, nesfatin-1, and resistin in T2DM patients at one year after both RYGB and SG, whereas post-glucagon suppression of plasma obestatin and resistin was shown in the remitters but not in the non-remitters.

Nesfatin-1 - More than a food intake regulatory peptide

Nesfatin-1 was discovered a decade ago and despite the fact that it represents just one of a multitude of food intake-inhibiting factors it received increasing attention. This led to a detailed characterization of NUCB2/nesfatin-1's physiological property to reduce food intake and also gave rise to an involvement in the long term regulation of body weight, especially under conditions of obesity. In addition, studies indicated the involvement of NUCB2/nesfatin-1 in other homeostatic functions as well: glucose homeostasis, water intake, gastrointestinal functions, temperature regulation, cardiovascular functions, puberty onset and sleep. These pleiotropic actions underline the physiological relevance of this peptide. Recently, the involvement of NUCB2/nesfatin-1 in psychiatric disorders such as anxiety has been investigated giving rise to the speculation that NUCB2/nesfatin-1 represents a peptidergic link between eating and anxiety/depression disorders.

The gut sensor as regulator of body weight

The gastrointestinal (GI) tract comprises a large endocrine organ that regulates not only nutrient sensing and metabolising but also satiety and energy homeostasis. More than 20 hormones secreted from the stomach, intestine, and pancreas as well as signaling mediators of the gut microbiome are involved in this process. A better understanding of how related pathways affect body weight and food intake will help us to find new strategies and drugs to treat obesity. For example, weight loss secondary to lifestyle intervention is often accompanied by unfavorable changes in multiple GI hormones, which may cause difficulties in maintaining a lower body weight status. Conversely, bariatric surgery favorably changes the hormone profile to support improved satiety and metabolic function. This partially explains stronger sustained body weight reduction resulting in better long-term results of improved metabolic functions. This review focuses on GI hormones and signaling mediators of the microbiome involved in satiety regulation and energy homeostasis and summarizes their changes following weight loss. Furthermore, the potential role of GI hormones as anti-obesity drugs is discussed.

Peripheral signals mediate the beneficial effects of gastric surgery in obesity

Obesity is nowadays a public health problem both in the industrialized world and developing countries. The different treatments to fight against obesity are not very successful with the exception of gastric surgery. The mechanism behind the achievement of this procedure remains unclear although the modifications in the pattern of gastrointestinal hormones production appear to be responsible for the beneficial effect. The gastrointestinal tract has emerged in the last time as an endocrine organ in charge of response to the different stimulus related to nutritional status by the modulation of more than 30 signals acting at central level to modulate food intake and body weight. The production of some of these gastric derived signals has been proved to be altered in obesity (ghrelin, CCK, and GLP-1). In fact, bariatric surgery modifies the production of both gastrointestinal and adipose tissue peripheral signals beyond the gut microbiota composition. Through this paper the main peripheral signals altered in obesity will be reviewed together with their modifications after bariatric surgery.

Can medical therapy mimic the clinical efficacy or physiological effects of bariatric surgery?

The number of bariatric surgical procedures performed has increased dramatically. This review discusses the clinical and physiological changes, and in particular, the mechanisms behind weight loss and glycaemic improvements, observed following the gastric bypass, sleeve gastrectomy and gastric banding bariatric procedures. The review then examines how close we are to mimicking the clinical or physiological effects of surgery through less invasive and safer modern interventions that are currently available for clinical use. These include dietary interventions, orlistat, lorcaserin, phentermine/topiramate, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, pramlintide, dapagliflozin, the duodenal-jejunal bypass liner, gastric pacemakers and gastric balloons. We conclude that, based on the most recent trials, we cannot fully mimic the clinical or physiological effects of surgery; however, we are getting closer. A 'medical bypass' may not be as far in the future as we previously thought, as the physician's armamentarium against obesity and type 2 diabetes has recently got stronger through the use of specific dietary modifications, novel medical devices and pharmacotherapy. Novel therapeutic targets include not only appetite but also taste/food preferences, energy expenditure, gut microbiota, bile acid signalling, inflammation, preservation of β-cell function and hepatic glucose output, among others. Although there are no magic bullets, an integrated multimodal approach may yield success. Non-surgical interventions that mimic the metabolic benefits of bariatric surgery, with a reduced morbidity and mortality burden, remain tenable alternatives for patients and health-care professionals.

Impact of bariatric surgery on ghrelin and obestatin levels in obesity or type 2 diabetes mellitus rat model

We aimed to evaluate the therapeutic efficacy on weight control by different bariatric surgeries and investigate the ghrelin and obestatin changes after these surgeries in obesity and nonobese type 2 diabetes mellitus (T2DM) rats. Obese rats were randomly assigned to receive sleeve gastrectomy (SG, n = 8), minigastric bypass (MGBP, n = 8), roux-en-Y gastric bypass (RYGBP, n = 8), and sham operation (SO, n = 4). Another 4 rats served as control. Besides, Goto-Kakisaki (GK) rats were also randomly divided into similar groups except for total gastrectomy (TG, n = 8) group. The results showed that in obese rats, weigh loss in RYGBP group was similar to that in MGBP group but larger than that in SG group. Ghrelin significantly increased in RYGB group, but obestatin increased in MGBP group. Ghrelin/obestatin ratio significantly decreased in SG group. In GK rats, weight loss was most obvious in TG group. Postoperatively, ghrelin was significantly increased in MGBP and RYGB groups but decreased in TG group. Obestatin also showed an increase in MGBP and RYGB groups. Ghrelin/obestatin in TG group decreased significantly. In conclusion, RYGB and MGBP may be more suitable for obese rats, but TG may be the best strategy for T2DM rats to control weight with different mechanisms.

The role of nesfatin-1 in the regulation of food intake and body weight: recent developments and future endeavors

Nesfatin-1 was discovered in 2006 and introduced as a potential novel anorexigenic modulator of food intake and body weight. The past years have witnessed increasing evidence establishing nesfatin-1 as a potent physiological inhibitor of food intake and body weight and unravelled nesfatin-1's interaction with other brain transmitters to exert its food consumption inhibitory effect. As observed for other anorexigenic brain neuropeptides, nesfatin-1 is also likely to exert additional, if not pleiotropic, actions in the brain and periphery. Recent studies established the prominent expression of the nesfatin-1 precursor, nucleobindin2 (NUCB2), in the stomach and pancreas, where nesfatin-1 influences endocrine secretion. This review will highlight the current experimental state-of-knowledge on the effects of NUCB2/nesfatin-1 on food intake, body weight and glucose homeostasis. Potential implications in human obesity will be discussed in relation to the evidence of changes in circulating levels of NUCB2/nesfatin-1 in disease states, the occurrence of genetic NUCB2 polymorphisms and--in contrast to several other hormones--the independence of leptin signalling known to be blunted under conditions of chronically increased body weight.