Gastric Sensory and Motor Functions and Energy Intake in Health and Obesity-Therapeutic Implications

The Possible Involvement of Glucagon-like Peptide-2 in the Regulation of Food Intake through the Gut-Brain Axis

Food intake regulation is a complex mechanism involving the interaction between central and peripheral structures. Among the latter, the gastrointestinal tract represents one of the main sources of both nervous and hormonal signals, which reach the central nervous system that integrates them and sends the resulting information downstream to effector organs involved in energy homeostasis. Gut hormones released by nutrient-sensing enteroendocrine cells can send signals to central structures involved in the regulation of food intake through more than one mechanism. One of these is through the modulation of gastric motor phenomena known to be a source of peripheral satiety signals. In the present review, our attention will be focused on the ability of the glucagon-like peptide 2 (GLP-2) hormone to modulate gastrointestinal motor activity and discuss how its effects could be related to peripheral satiety signals generated in the stomach and involved in the regulation of food intake through the gut-brain axis. A better understanding of the possible role of GLP-2 in regulating food intake through the gut-brain axis could represent a starting point for the development of new strategies to treat some pathological conditions, such as obesity.

TAAR1 agonist ulotaront delays gastric emptying of solids in patients with schizophrenia and concurrent metabolic syndrome with prediabetes

BACKGROUND

Metabolic syndrome (MetS), which can be induced or exacerbated by the current class of antipsychotic drugs, is highly prevalent in patients with schizophrenia and presents significant challenges to lifetime disease management. Supported by initial clinical results, trace amine-associated receptor 1 (TAAR1) agonists have emerged as potential novel treatments for schizophrenia. Notably, non-clinical studies have also shown weight-lowering and glucoregulatory effects of TAAR1 agonists, including the investigational agent ulotaront. However, the translatability of these findings to humans has not been adequately assessed. Given that delayed gastric emptying (GE) was identified as a potential mechanism contributing to the metabolic benefits of TAAR1 agonists in rodents, the aim of this study was to evaluate the effect of ulotaront on GE in patients with schizophrenia and concurrent MetS with prediabetes.

METHODS

Patients with schizophrenia were randomized to receive a single oral dose of ulotaront (150 mg) and their previous antipsychotic (PA) in an open-label, crossover, two-sequence design (NCT05402111). Eligible participants fulfilled at least three of five MetS criteria and had prediabetes defined by elevated glycated haemoglobin (5.7-6.4%) and/or fasting homeostatic model assessment of insulin resistance (i.e. ≥2.22). Following an overnight fast and 4 h post-dose, participants ingested a 99mTc-sulphur colloid radiolabelled egg meal (320 kcal, 30% fat). GE was measured by scintigraphy over 4 h. Endpoints included GE of solids half-time (T1/2) and percentage gastric retention at 1, 2 and 4 h.

RESULTS

Thirty-one adults were randomized and 27 completed the study. Ulotaront significantly delayed GE of solids [median GE T1/2 ulotaront at 139 min (119, 182) vs. the participant's PA of 124 min (109, 132), p = .006]. A significant increase in gastric retention was seen in the ulotaront versus the PA group at 1 h (80% vs. 75%, p = .015), 2 h (61% vs. 50%, p = .023) and 4 h (17% vs. 7%, p = .002) post-meal.

CONCLUSION

Ulotaront delayed the GE of solids in patients with schizophrenia and concurrent MetS with prediabetes. Additional studies are needed to assess whether treatment with TAAR1 agonists is associated with weight loss and glucoregulatory improvement.

Leptin-Melanocortin pathway variants and gastric emptying in patients with obesity

BACKGROUND

Accelerated gastric emptying (GE) is a trait seen in obesity. Mutations in the hypothalamic leptin-melanocortin 4 receptor (Leptin-MC4R) pathway have been associated with obesity. We sought to investigate the association of leptin-MC4R pathway variants and GE in patients with obesity.

METHODS

This is a cross-sectional study of patients with a history of severe obesity that were genotyped and completed a GE test by scintigraphy. We evaluated the percentage of GE (GE %) at 2 and 4 h between both groups using ANCOVA with weight and sex as covariates. We subdivide patients into carriers based on the location of the identified variants (i.e., upstream or downstream of the Leptin-MC4R pathway) and compared them with noncarriers using ANOVA. Results are presented as mean and standard deviation (± SD).

KEY RESULTS

A total of 95 patients; nine carriers (67% females; 39.78 ± 12.33 years; BMI: 49.14 ± 12.96 kg/m2) and 86 noncarriers (87% female; 49.98 ± 13.74 years; BMI: 40.75 ± 6.29 kg/m2) were included. At 2 and 4 h, carriers had a delayed GE when compared noncarriers (p = 0.03 and p = 0.005, respectively). In carriers, when compared upstream carriers vs. downstream carriers vs. noncarriers by location there was a significant difference in GE among groups at 2 h and at 4 h (p = 0.02 and p = 0.01, respectively).

CONCLUSIONS & INFERENCES

Carriers of heterozygous variants in the Leptin-MC4R pathway had a delayed GE compared to noncarriers. These findings point the important relationship between the Leptin-MC4R pathway and gastric motility.

How to establish an endoscopic bariatric practice

Obesity is a chronic, progressive, and relapsing disease of excess adiposity that contributes to more than two hundred medical conditions and is projected to affect more than half the adult population of the United States by the year 2030. Given the limited penetrance of traditional bariatric surgery, as well as the cost and adherence barriers to anti-obesity medications, there is growing interest in the rapidly evolving field of endoscopic bariatric therapies (EBTs). EBTs are minimally invasive, same-day, per-oral endoscopic procedures and include endoscopic sleeve gastroplasty, intragastric balloons, and endoscopic bariatric revisional procedures. This field represents an exciting and innovative subspecialty within gastroenterology. However, building a successful endoscopic bariatric practice requires intentional, coordinated, and sustained efforts to overcome the numerous obstacles to entry. Common barriers include acquisition of the technical and cognitive skillset, practice limitations including the availability of nutrition counseling, facility capabilities, direct-to-consumer marketing, and financial pressures such as facility and anesthesia fees. As the highest-volume center for metabolic and bariatric endoscopy in the United States, we provide insights into successfully establishing an endoscopic bariatric program.

TRPV4 in adipose tissue ameliorates diet-induced obesity by promoting white adipocyte browning

The induction of adipocyte browning to increase energy expenditure is a promising strategy to combat obesity. Transient receptor potential channel V4 (TRPV4) functions as a nonselective cation channel in various cells and plays physiological roles in osmotic and thermal sensations. However, the function of TRPV4 in energy metabolism remains controversial. This study revealed the role of TRPV4 in adipose tissue in the development of obesity. Adipose-specific TRPV4 overexpression protected mice against diet-induced obesity (DIO) and promoted white fat browning. TRPV4 overexpression was also associated with decreased adipose inflammation and improved insulin sensitivity. Mechanistically, TRPV4 could directly promote white adipocyte browning via the AKT pathway. Consistently, adipose-specific TRPV4 knockout exacerbated DIO with impaired thermogenesis and activated inflammation. Corroborating our findings in mice, TRPV4 expression was low in the white adipose tissue of obese people. Our results positioned TRPV4 as a potential regulator of obesity and energy expenditure in mice and humans.

Liraglutide modulates morpho-functional and inflammatory gastrointestinal responses in rats

BACKGROUND

Obesity impairs homeostatic control of energy and is associated with chronic low-grade inflammation. Effects of glucagon-like peptide-1, the target in the gastrointestinal tract for anti-obesity drugs such as Liraglutide, were not properly associated with inflammation markers. This study investigated the effects of Liraglutide on metabolic and gastrointestinal parameters in a rat model of obesity.

METHODS

Twenty-six Wistar rats with obesity were randomly distributed to receive saline (n = 10), 400 μg (n = 8), or 1200 μg of Liraglutide/kg/day (n = 8), subcutaneously for 30 consecutive days, once a day. Weight gain, feeding efficiency, caloric consumption, gastric motility, adiposity, histomorphometric, murinometric, biochemical parameters and cytokines TNF-α and TGF-β1 in duodenal tissue were measured. Data were analysed by ANOVA, followed by Bonferroni post hoc or Kruskal-Wallis test, followed by Dunn's multiple comparison test.

RESULTS

Liraglutide-treated animals had better feeding efficiency and higher caloric intake in a dose-dependent manner. Higher doses slowed gastric emptying and diminished the amplitude of gastric contractions. These effects were accompanied by decreases in intestinal muscle layer thickness and crypt depth. Liraglutide significantly reduced retroperitoneal and visceral white adipose tissue depots. High-dose treatment decreased levels of TNF-α and enhanced levels of TGF-β1 in duodenal tissue. Liraglutide treatment provided significant reductions in total cholesterol, triglyceride and hepatic transaminases.

CONCLUSIONS

Liraglutide reduced fat accumulation, improved metabolic parameters and downregulated levels of inflammatory signalling in duodenal tissue. Liraglutide at high doses controlled obesity-related outcomes, and such effects seemed to be driven by its action on glucagon-like peptide-1 receptors in the gastrointestinal tract slowing gastric motility.

TAAR1 agonists improve glycemic control, reduce body weight and modulate neurocircuits governing energy balance and feeding

OBJECTIVE

Metabolic Syndrome, which can be induced or exacerbated by current antipsychotic drugs (APDs), is highly prevalent in schizophrenia patients. Recent preclinical and clinical evidence suggest that agonists at trace amine-associated receptor 1 (TAAR1) have potential as a new treatment option for schizophrenia. Intriguingly, preclinical tudies have also identified TAAR1 as a novel regulator of metabolic control. Here we evaluated the effects of three TAAR1 agonists, including the clinical development candidate ulotaront, on body weight, metabolic parameters and modulation of neurocircuits implicated in homeostatic and hedonic feeding.

METHODS

Effects of TAAR1 agonists (ulotaront, RO5166017 and/or RO5263397) on body weight, food intake and/or metabolic parameters were investigated in rats fed a high-fat diet (HFD) and in a mouse model of diet-induced obesity (DIO). Body weight effects were also determined in a rat and mouse model of olanzapine-, and corticosterone-induced body weight gain, respectively. Glucose tolerance was assessed in lean and diabetic db/db mice and fasting plasma glucose and insulin examined in DIO mice. Effects on gastric emptying were evaluated in lean mice and rats. Drug-induced neurocircuit modulation was evaluated in mice using whole-brain imaging of c-fos protein expression.

RESULTS

TAAR1 agonists improved oral glucose tolerance by inhibiting gastric emptying. Sub-chronic administration of ulotaront in rats fed a HFD produced a dose-dependent reduction in body weight, food intake and liver triglycerides compared to vehicle controls. In addition, a more rapid reversal of olanzapine-induced weight gain and food intake was observed in HFD rats switched to ulotaront or RO5263397 treatment compared to those switched to vehicle. Chronic ulotaront administration also reduced body weight and improved glycemic control in DIO mice, and normalized corticosterone-induced body weight gain in mice. TAAR1 activation increased neuronal activity in discrete homeostatic and hedonic feeding centers located in the dorsal vagal complex and hypothalamus with concurrent activation of several limbic structures.

CONCLUSION

The current data demonstrate that TAAR1 agonists, as a class, not only lack APD-induced metabolic liabilities but can reduce body weight and improve glycemic control in rodent models. The underlying mechanisms likely include TAAR1-mediated peripheral effects on glucose homeostasis and gastric emptying as well as central regulation of energy balance and food intake.

Comparative effectiveness of GLP-1 receptor agonists on glycaemic control, body weight, and lipid profile for type 2 diabetes: systematic review and network meta-analysis

OBJECTIVE

To evaluate the comparative efficacy and safety of glucagon-like peptide-1 receptor agonists (GLP-1RAs) on glycaemic control, body weight, and lipid profile in adults with type 2 diabetes.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

PubMed, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase from database inception to 19 August 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Eligible randomised controlled trials enrolled adults with type 2 diabetes who received GLP-1RA treatments and compared effects with placebo or any GLP-1RA drug, with a follow-up duration of at least 12 weeks. Trials with a crossover design, non-inferiority studies comparing GLP-1RA and other drug classes without a placebo group, using withdrawn drugs, and non-English studies were deemed ineligible.

RESULTS

76 eligible trials involving 15 GLP-1RA drugs and 39 246 participants were included in this network meta-analysis; all subsequent estimates refer to the comparison with placebo. All 15 GLP-1RAs effectively lowered haemoglobin A1c and fasting plasma glucose concentrations. Tirzepatide induced the largest reduction of haemoglobin A1c concentrations (mean difference -2.10% (95% confidence interval -2.47% to -1.74%), surface under the cumulative ranking curve 94.2%; high confidence of evidence), and fasting plasma glucose concentrations (-3.12 mmol/L (-3.59 to -2.66), 97.2%; high confidence), and proved the most effective GLP-1RA drug for glycaemic control. Furthermore, GLP-1RAs were shown to have strong benefits to weight management for patients with type 2 diabetes. CagriSema (semaglutide with cagrilintide) resulted in the highest weight loss (mean difference -14.03 kg (95% confidence interval -17.05 to -11.00); high confidence of evidence), followed by tirzepatide (-8.47 kg (-9.68 to -7.26); high confidence). Semaglutide was effective in lowering the concentration of low density lipoprotein (-0.16 mmol/L (-0.30 to -0.02)) and total cholesterol (-0.48 mmol/L (-0.84 to -0.11)). Moreover, this study also raises awareness of gastrointestinal adverse events induced by GLP-1RAs, and concerns about safety are especially warranted for high dose administration.

CONCLUSIONS

GLP-1RAs are efficacious in treating adults with type 2 diabetes. Compared with the placebo, tirzepatide was the most effective GLP-1RA drug for glycaemic control by reducing haemoglobin A1c and fasting plasma glucose concentrations. GLP-1RAs also significantly improved weight management for type 2 diabetes, with CagriSema performing the best for weight loss. The results prompt safety concerns for GLP-1RAs, especially with high dose administration, regarding gastrointestinal adverse events.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022342845.

Oral stimulation with glucose and fructose, but not sucrose, accelerates gastric emptying in humans

Postprandial regulation of the gastric emptying (GE) rate plays an important role in food intake. Although oral sweetening with glucose may accelerate GE, the effects of different sweetness intensities of glucose (10% and 20%, w/v) and other energy sweeteners (e.g. fructose and sucrose) remain uncertain. The purpose of this study was to determine the effects of different glucose concentrations (Experiment 1) and different sugars with the same sweet taste intensity (Experiment 2) on postprandial GE. In both experiments, after ingesting a 200 kcal carbohydrate solution containing 50 g of maltodextrin, participants repeatedly sipped, but did not swallow, one of three (water, 10% and 20%, w/v glucose) or four (water and equally sweet 20%, w/v glucose, 12%, w/v fructose, and 14%, w/v sucrose) solutions for 1 min every 5 min over a 30 min period. GE was evaluated by measuring the temporal change in the cross-sectional area of the gastric antrum using ultrasound. In Experiment 1, oral stimulation with 20% (w/v) glucose resulted in greater GE than the control stimulus (i.e. water), but the effect of stimulation with 10% (w/v) glucose on GE was not different from that of the control stimulus. In Experiment 2, stimulation with 20% (w/v) glucose or 12% (w/v) fructose resulted in greater GE than the control stimulus. However, the effect of stimulation with 14% (w/v) sucrose on GE did not differ from that of the control stimulus. Consequently, oral stimulation with glucose or fructose solutions of moderate to high sweetness following a meal facilitates postprandial GE.

Embracing the Pros and Cons of the New Weight Loss Medications (Semaglutide, Tirzepatide, Etc.)

PURPOSE OF REVIEW

The history of multiple weight loss medications has been a concerning paradox based on an increased cardiovascular risk despite significant reductions in adipose tissue and weight. A new class of weight loss medications could change this past narrative based on early preliminary results of cardiovascular risk (not events-still need to be determined) and weight reduction in non-diabetics that acutely competes with results achieved with bariatric surgery. The purpose of this review is to provide a comprehensive summary of the advantages and disadvantages of these newer medications, and how they could impact urology.

RECENT FINDINGS

Weight loss of - 15 to - 20% compared to baseline has become plausible in the short-term and preliminary guidance to reduce acute and chronic adverse events are receiving attention. However, the cost, access, conflicts of interest, supply chain, life-long adherence issues, and the long-term diverse implications on mental and physical health when exposed to this class of medications (GLP-1 agonists) are unknown. The profound caloric reductions should also result in baseline or ongoing nutritional deficiency testing, and general and specific dietary recommendations, which could theoretically mimic some bariatric surgery pre- and post-surgical protocols but has yet to be studied. Regardless, the potential impact of these medicines within a variety of medical specialties needs clinical research. Current and future lifestyle interventions, dietary patterns, and medicines in the weight loss category need to be held to a paradigm whereby cardiovascular health should improve with significant weight loss without a negative impact on mental health. In urology, the ability to impact cancer risk, ED, FSD, incontinence, infertility, nephrolithiasis, and multiple other endpoints are plausible (based on bariatric surgery data) but need preliminary clinical research. Other medicines with a similar or even larger potential impact are in clinical trials, and thus, a concise overview for clinicians and researchers was needed for objective guidance. Currently, comprehensive lifestyle changes utilized with and without these medications continue to garner positive mental, physical, and legacy effects, which suggest that they are as necessary as ever in the treatment of the numerous conditions impacted by unhealthy weight gain.

Factors associated with successful weight loss after liraglutide treatment for obesity

AIM

To identify patient factors, including gastrointestinal functions, that are predictive or associated with weight loss in response to once-daily 3 mg liraglutide administered subcutaneously (SQ) or placebo in obesity.

METHODS

One hundred and thirty-six obese adults (87% female) were randomized in a placebo-controlled, 16-week trial of liraglutide, escalated to 3 mg administered SQ daily. Gastrointestinal functions were measured at baseline and 16 weeks: gastric emptying of solids (GET1/2 ); fasting and postprandial gastric volumes; kcal ingested during ad libitum buffet meal and the nutrient drink test. GET1/2 was also measured at 5 weeks. A multiple variable regression model examined variables associated with weight loss of more than 4 kg at 16 weeks. A parsimonious model using backward selection identified the final model.

RESULTS

Weight loss of more than 4 kg at 16 weeks occurred in 71% of liraglutide- and 16% of placebo-treated patients. In all participants combined, parameters univariately associated with a weight loss of more than 4 kg were GET1/2 at 5 and 16 weeks, weight loss at 5 weeks and kcal intake during the buffet meal at 16 weeks. The final parsimonious model (area under the receiver operator characteristics [AUROC] curve = 0.832) identified that factors associated with more than 4-kg weight loss were GET1/2 at 5 weeks (OR = 2.505; 95% CI: 1.57-3.997) per 50 minutes and kcal intake during ad libitum meal at 16 weeks (OR = 0.721; 95% CI: 0.602-0.864) per 100 kcal. Among only the 60 liraglutide-treated subjects, kcal intake at 16 weeks was associated with 4-kg weight loss (AUROC = 0.757).

CONCLUSIONS

Slower GET1/2 and weight loss at 5 weeks predicted a weight loss of more than 4 kg at 16 weeks in all participants. Among liraglutide-treated adults, weight loss of more than 4 kg was associated with ad libitum meal kcal intake at 16 weeks.

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

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

Stearic acid induces CCK and GLP-1 upregulation via GPR120/PLC-β, leading to reduced appetite in Hu sheep fed with rice straw

Due to the poor palatability of straw, feeding untreated rice straw reduces ruminant feed intake, thus affecting the production efficiency of animal husbandry. However, the detailed mechanism by which straw affects ruminants' feed intake is unclear. Therefore, this study aimed to elucidate the molecular mechanism by which a rice straw (RS)-based diet affects appetite regulation in Hu sheep. We found that RS promoted the secretion of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) and decreased feed intake. Blood metabolomics showed that RS activated the arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and alpha-linolenic acid metabolism pathways, and the secretion of stearic acid (SA), their metabolic end product, increased significantly. GPR120, one of the classical receptors of long-chain fatty acids (LCFAs), can be involved in appetite regulation. However, the role of SA in satiety hormone regulation mediated by GPR120 in ruminants is unclear. In this study, in vivo experiments showed that in sheep fed with RS, SA increased significantly and activated GPR120/Ca²⁺, increasing the secretion of the satiety hormones CCK and GLP-1. In vitro mechanism studies showed that SA promotes GLP-1 and CCK secretion by activating GPR120-mediated downstream PKC and IP3R signaling pathways of PLCβ.

A Serious Game for the Prevention of Obesity in School Children–Impact of Parent’s Involvement: A Randomized Controlled Trial

Serious games convey information and use interactive components to reinforce and train behaviours. A serious game addressing nutrition, physical activity and stress coping—the Kids Obesity Prevention Program (KOP)—was previously evaluated for efficacy in children. This study aimed at evaluating the KOP-game regarding: (i) its acceptance and efficacy with respect to parents of primary school children receiving the same game intervention as the children; and (ii) whether the children could benefit by parental involvement. A randomized controlled trial with two groups of children aged 9 to 12 years was conducted which included a 6-month follow-up period. All children played the game twice in two weeks. In the family-intervention group, the parents additionally played the game. The primary outcome was the gain in knowledge in parents and children measured with a pretested questionnaire. The secondary outcomes were knowledge maintenance as well as several behavior changes. Parents and children in both groups improved and maintained their knowledge equally. The KOP-game increases knowledge of nutrition in children independently of the involvement of their parents. KOP games are well accepted in children; further research should examine the structured involvement of parents.

Association of Dietary Energy Intake With Constipation Among Men and Women: Results From the National Health and Nutrition Examination Survey

Background

Previous studies supported that dietary factor was associated with constipation, but the relationship between dietary energy intake and constipation has not been well-studied. Therefore, we aimed to evaluate the prevalence and correlation between energy intake and constipation among men and women.

Methods

These observational analyses included 12,587 adults (≥20 years) from the 2005–2010 cycles of the National Health and Nutrition Examination Surveys (NHANES). Constipation was defined as Bristol Stool Scale Type 1 (separate hard lumps, like nuts) or Type 2 (sausage-like but lumpy). Total energy intake was obtained from the two 24-h dietary recalls and averaged. We used the logistic regression model in Generalized Linear Model (GLM) function, controlling demographic, lifestyle, and dietary factors, to estimate the association between energy intake and constipation among men and women.

Results

The overall weighted incidence of constipation in this research was 7.4%, the incidence in women and men was 10.4 and 4.3%, respectively. After multivariable adjustment, middle energy consumption correlated with decreased risk of constipation in men (OR:0.5, 95% CI:0.29–0.84), and lower-middle energy intake increased the constipation risk in women (OR: 1.56, 95% CI: 1.15–2.13). High energy consumption was not associated with increased or decreased constipation risk.

Conclusions

To our knowledge, this is the first research to investigate the association between energy intake and constipation; the study demonstrates that appropriate energy consumption can help reduce the risk of constipation in men, and relatively low energy intake is associated with increased constipation risk in women.

Chronic nausea and vomiting: a diagnostic approach

INTRODUCTION

Chronic nausea and vomiting (CNV) are commonly encountered symptoms in medical practice. CNV is the presenting symptom in a variety of gastrointestinal and non-gastrointestinal disorders. However, in a significant percentage of patients without an obvious underlying cause, CNV poses a significant diagnostic challenge to the evaluating physician.

AREAS COVERED

A comprehensive clinical history and physical examination form the foundation for further diagnostic work-up. In the present review, we discuss the diagnostic approach to CNV, highlighting the epidemiology, pathophysiology, causes, and modes of evaluation of this condition. Specific investigations, carefully guided by clinical assessment and tailored for each patient, would be more beneficial in diagnosing CNV than empirically performing a blanket of investigations.

EXPERT OPINION

Whilst CNV remains a historically challenging diagnostic and therapeutic dilemma, research into this topic is limited. Hence, there is a growing call for more research into diagnostic modalities for CNV. With scientific advancement and further research, it is hoped that easy-to-use, cheap, noninvasive novel diagnostic modalities for CNV will be available soon.

Energy Imbalance Gap, Anthropometric Measures, Lifestyle, and Sociodemographic Correlates in Latin American Adults-Results from the ELANS Study

Overweight and obesity are often explained by an imbalance between energy intake and expenditure. This, in addition to metabolic effects, makes it difficult to assess the real state of individual energy balance. This study aims to analyze the energy gaps between intake and expenditure in the adult population of Latin America, as well as its relationships with sociodemographic variables and nutrition status, to draw an epidemiological perspective based on the trends observed. The energy imbalance gap was used to this end. The difference between energy intake and expenditure can be applied as a reference to explain whether weight equilibrium can prevent weight gain. Moreover, the energy imbalance gap allows for a better understanding of the design of public health policies. Using data from the Latin American Study of Nutrition and Health, the energy imbalance gap in adult population from eight Latin-American countries was assessed in 5994 subjects aged from 19-65. Usual dietary intake was measured using two non-consecutive 24 h dietary recalls. The sociodemographic questionnaire was supplemented by anthropometric measurements. Physical activity was measured through the long International Physical Activity Questionnaire. Energy expenditure was obtained using the basal metabolic rate. For the overall sample, the mean energy intake was 1939.1 kcal (95% CI: 1926.9; 1951.3), the mean of energy expenditure was 1915.7 kcal (95% CI: 1906.4; 1924.9), and the mean of energy imbalance gap was 23.4 kcal (95% CI: 11.9; 35.0). Results show that energy intake and expenditure were higher in men. Moreover, subjects aged 19-34, of high socioeconomic level, who completed high school, were mestizos and were of normal weight consumed the highest number of calories. Overall, a positive energy imbalance gap was observed. Overweight and obese from Argentina, Costa Rica, Ecuador, Peru, and Venezuela showed a significantly lower energy imbalance gap than underweight subjects. These findings confirm the high variability of energy imbalance gap and the accompanying correlates of energy intake and expenditure. Further research is needed to specifically address interventions in low and middle-income countries such as many in Latin America, to help reduce the prevalence of obesity and eradicate undernutrition.

Association of Glucagon-like Peptide 1 Analogs and Agonists Administered for Obesity with Weight Loss and Adverse Events: A Systematic Review and Network Meta-analysis

BACKGROUND

Comparative effectiveness of 7 glucagon-like peptide 1 (GLP-1) agents on weight loss (WL) in obesity remains unknown.

METHODS

We performed a systematic review, network meta-analysis (NMA) utilizing the following data sources: MEDLINE, EMBASE, Scopus, Cochrane Central and clinical trial registries, from inception to March 2, 2021. The prespecified criteria for study inclusion were randomized clinical trials (RCTs) of ≥12 weeks' duration. The data appraisal and extraction were performed by two investigators independently, using the published reports. The main outcomes and statistical methods were weight loss over placebo (WLOP) and adverse events (AEs) among GLP-1 agents using random-effects NMA (frequentist approach); relative ranking using surface under the cumulative ranking (SUCRA) method and certainty of evidence using grading of recommendations, assessment, development and evaluations (GRADE).

FINDINGS

64 RCTs (from 2004 to 2021) included 27018 patients (median of age, 55.1 years old; 57.4% women; baseline weight 94.8kg and BMI 33.0kg/m2; trial duration 26 weeks). Direct meta-analysis showed significant WLOP with: -1.44kg (95% CI, -2.14 to -0.74) with dulaglutide ≥1.5 mg; -1.82kg (-2.42 to -1.23) with exenatide immediate release (IR); -2.20kg (-4.31 to -0.08) with exenatide extended release (ER); -3.20kg (-6.53 to 0.15) with efpeglenatide; -2.72kg (-3.35 to -2.09) with liraglutide ≤1.8mg; -4.49kg (-5.26 to -3.72) with liraglutide >1.8mg; -0.62kg (-1.22 to -0.02) with lixisenatide; -4.33kg (-5.71 to -3.00) with semaglutide SQ <2.4mg; -9.88kg (-13.17 to -6.59) with semaglutide SQ 2.4mg; -2.73kg (-4.81 to -0.65) with semaglutide oral; and -1.71kg (-2.64 to -0.78) with taspoglutide. Highest WLOP were with semaglutide SQ 2.4mg and <2.4mg, and liraglutide >1.8mg (SUCRAs 100, 86.1, 82.8 respectively). Highest SUCRAs for discontinuation due to AEs were with taspoglutide and liraglutide >1.8mg. Risk of bias was high or unclear for random sequence generation (29.7%), allocation concealment (26.6%), and incomplete outcome data (26.6%). Heterogeneity (I2 >50%) in WL and AEs reflected magnitude, not direction of effect.

Appetite and Satiety Control-Contribution of Gut Mechanisms

The prevalence of obesity, and its comorbidities, particularly type 2 diabetes, cardiovascular and hepatic disease and certain cancers, continues to rise at an alarming rate worldwide [...].

Nitric Oxide: From Gastric Motility to Gastric Dysmotility

It is known that nitric oxide (NO) plays a key physiological role in the control of gastrointestinal (GI) motor phenomena. In this respect, NO is considered as the main non-adrenergic, non-cholinergic (NANC) inhibitory neurotransmitter responsible for smooth muscle relaxation. Moreover, many substances (including hormones) have been reported to modulate NO production leading to changes in motor responses, further underlying the importance of this molecule in the control of GI motility. An impaired NO production/release has indeed been reported to be implicated in some GI dysmotility. In this article we wanted to focus on the influence of NO on gastric motility by summarizing knowledge regarding its role in both physiological and pathological conditions. The main role of NO on regulating gastric smooth muscle motor responses, with particular reference to NO synthases expression and signaling pathways, is discussed. A deeper knowledge of nitrergic mechanisms is important for a better understanding of their involvement in gastric pathophysiological conditions of hypo- or hyper-motility states and for future therapeutic approaches. A possible role of substances which, by interfering with NO production, could prove useful in managing such motor disorders has been advanced.