Effect of the GLP-1 analog liraglutide on satiation and gastric sensorimotor function during nutrient-drink ingestion

Gastrointestinal hormones and regulation of gastric emptying

PURPOSE OF REVIEW

In this review, we evaluate recent findings related to the association between gastrointestinal hormones and regulation of gastric emptying.

RECENT FINDINGS

Motilin and ghrelin, which act during fasting, promote gastric motility, whereas most of the hormones secreted after a meal inhibit gastric motility. Serotonin has different progastric or antigastric motility effects depending on the receptor subtype. Serotonin receptor agonists have been used clinically to treat dyspepsia symptoms but other hormone receptor agonists or antagonists are still under development. Glucagon-like peptide 1 agonists, which have gastric motility and appetite-suppressing effects are used as a treatment for obesity and diabetes.

SUMMARY

Gastrointestinal hormones play an important role in the regulation of gastric motility. Various drugs have been developed to treat delayed gastric emptying by targeting gastrointestinal hormones or their receptors but few have been commercialized.

The effect of prucalopride on gastric sensorimotor function and satiation in healthy volunteers

BACKGROUND

Gastric motor function alterations have been implicated in the pathogenesis of functional dyspepsia with postprandial distress syndrome (PDS). Prucalopride, a 5-TH4 agonist, is known to stimulate gastrointestinal motility. We aimed to evaluate the effect of prucalopride on gastric sensorimotor function in healthy subjects (HV).

METHODS

Barostat and intragastric pressure (IGP) measurements were performed in 17 HV (59% females, age 29.4 ± 2.7 y) after treatment with placebo or prucalopride (2 mg) (single-blind cross-over). Isobaric stepwise distensions and gastric sensations were assessed to determine gastric compliance and sensitivity. Gastric accommodation (GA) with the barostat was quantified before and after ingestion of 200 ml of a nutrient drink (ND). GA measured by IGP was quantified as the drop of IGP from baseline during the intragastric infusion of ND until maximal satiation (60 ml/min).

KEY RESULTS

Prucalopride did not affect barostat assessed gastric compliance or sensitivity. No differences were observed in GA after prucalopride. During the barostat study, 10 min after the meal, 7 HVs reported significantly higher ratings for nausea after prucalopride (p < 0.001), and vomiting was induced in 4 of the HVs. A positive correlation was observed between the delta mean perception of nausea with the delta mean increase of intra-balloon volume before and after meal ingestion (r = 0.37, p = 0.03). During IGP measurements, no effect on nutrient tolerance was observed and increased cramp severity scores were observed which were associated with a significant increase of distal IGP (r = 0.78, p < 0.0001).

CONCLUSIONS & INFERENCES

Prucalopride does not enhances gastric accommodation but it might increase sensitivity to gastric distention. Furthermore, the increase in sensitivity seems to be related to an increase in nausea with distension. Clinicaltrials.gov: NCT04429802.

Impact of joint hypermobility syndrome on gastric accommodation and nutrient tolerance in functional dyspepsia

Functional dyspepsia (FD) is defined as the presence of gastroduodenal symptoms in the absence of organic disease that is likely to explain the symptoms. Joint hypermobility (JH) refers to the increased passive or active movement of a joint beyond its normal range and is characteristically present in patients with joint hypermobility syndrome (JHS), which is a hypermobile subtype of Ehlers-Danlos syndrome (EDS). Recent reports have highlighted the co-existence of FD with Ehlers-Danlos syndrome. Our aim was to study the prevalence of JHS in FD compared with healthy subjects and to study the impact of co-existing JHS on gastric motility, nutrient tolerance, and dyspeptic symptoms in FD.

METHODS

FD patients filled out a dyspepsia symptom severity score. Intragastric pressure (IGP) was measured with high-resolution manometry (HRM) during the intragastric infusion of nutrition drink (ND, 1.5 Kcal/ml, 60 ml/min) until maximal satiation in healthy subjects and FD. We compared IGP profiles and nutrient tolerance in HS and FD with or without JHS.

RESULTS

JHS was present in 54% of FD patients (n = 39, 41.2 ± 2.2 years old) and 7% of healthy subjects (n = 15, 27.3 ± 2.3 years old). IGP drop and nutrient tolerance were lower in non-JHS-FD compared with JHS-FD and HS (AUC JHS-FD: -17.9 ± 2.5 vs. non-JHS-FD: -13.0 ± 3.3 mmHg min, p = 0.2, HS:-19.6 ± 2.9 mmHg min; ND tolerance non-JHS-FD: 671.0 ± 96.0 vs. JHS-FD: 842.7 ± 105.7 Kcal, p = 0.25, HS: 980.0 ± 108.1 Kcal).

CONCLUSION

JHS often co-exists with FD. Non-JHS-FD was characterized by decreased accommodation and lower nutrient tolerance characterized compared with JHS-FD. Clinicaltrials.gov, reference number NCT04279990.

The gastrointestinal tract in hunger and satiety signalling

BACKGROUND

Different peripheral pathways are implicated in the regulation of the food ingestion-digestion cycle.

METHODS

Narrative review on gastrointestinal mechanisms involved in satiety and hunger signalling.

RESULTS

Combined mechano- and chemoreceptors, peripherally released peptide hormones and neural pathways provide feedback to the brain to determine sensations of hunger (increase energy intake) or satiation (cessation of energy intake) and regulate the human metabolism. The gastric accommodation reflex, which consists of a transient relaxation of the proximal stomach during food intake, has been identified as a major determinant of meal volume, through activation of tension-sensitive gastric mechanoreceptors. Motilin, whose release is the trigger of gastric Phase 3, has been identified as the major determinant of return of hunger after a meal. In addition, the release of several peptide hormones such as glucagon-like peptide 1 (GLP-1), cholecystokinin as well as motilin and ghrelin contributes to gut-brain signalling with relevance to control of hunger and satiety. A number of nutrients, such as bitter tastants, as well as pharmacological agents, such as endocannabinoid receptor antagonists and GLP-1 analogues act on these pathways to influence hunger, satiation and food intake.

CONCLUSION

Gastrointestinal mechanisms such as gastric accommodation and motilin release are key determinants of satiety and hunger.

Duodenal nutrient exposure contributes to enhancing gastric accommodation

BACKGROUND

The gastric accommodation reflex consists of a relaxation which creates a reservoir for the ingested food before emptying to the duodenum occurs. The mechanisms that control gastric accommodation are not fully understood. This study aims to use intragastric pressure (IGP) measurement and pyloric balloon obstruction to determine the contribution of duodenal nutrient exposure to gastric accommodation and meal-induced satiation.

METHODS

Two conditions were tested in 11 healthy subjects (28.3 ± 3.2 years; 23.6 ± 0.7 kg/m² ; four females). IGP was measured during an intragastric nutrient drink (ND) infusion at a constant rate (60 mL/min) in the presence of a deflated (control) or inflated (pyloric obstruction) balloon placed into the pylorus. During the study, subjects filled out Likert scales for satiation scores and visual analogue scale for 9 epigastric symptoms (hunger, expected amount to eat, satiation, bloating, fullness, nausea, belching, gastric cramps, and pain) before and during ND infusion until maximal satiation.

KEY RESULTS

During pyloric obstruction, the IGP drop and the area above the IGP curve (AAC) were significantly smaller compared with the control condition (6.7 ± 1.0 mm Hg vs3.6 ± 0.8 mm Hg, P = .03 and 69.7 ± 13.5 mm Hg × min vs 20.1 ± 9.0 mm Hg × min, P = .001, respectively). Pyloric obstruction decreased nutrient tolerance compared with the control condition (787.9 ± 73.1 mL vs 970.9 ± 79.2 mL, respectively, P < .05). Pyloric obstruction increased symptoms of bloating (1.3 ± 0.4 vs 2.6 ± 0.6; P = .04), fullness (2.3 ± 0.5 vs 3.6 ± 0.3; P = .03), and nausea (0.4 ± 0.2 vs 1.3 ± 0.4; P = .04) compared to control.

CONCLUSION & INFERENCES

Duodenal nutrient exposure contributes to enhancing gastric accommodation. Preventing the passage of nutrients from the stomach to the duodenum inhibits gastric accommodation and increases meal-induced satiation, bloating, nausea, and fullness.

Randomised clinical trial: the DPP-4 inhibitor, vildagliptin, inhibits gastric accommodation and increases glucagon-like peptide-1 plasma levels in healthy volunteers

BACKGROUND

Dipeptidyl peptidase-4 (DPP-4) inactivates glucagon-like peptide-1 (GLP-1). Whether DPP-4 inhibition affects GLP-1 metabolism and/or food intake in humans remains unknown.

AIMS

To evaluate the effect of vildagliptin (DPP-4 inhibitor) on gastric accommodation and ad libitum food intake in healthy volunteers (HVs) METHODS: The effects of acute oral vildagliptin administration (50 mg) were evaluated in two randomised, placebo-controlled, single-blinded trials. Protocol 1 (n = 10, 32.3 ± 3 years, 23.4 ± 0.7 kg/m² ): 60 min after treatment, a nutrient drink (270 kcal) was infused intragastrically and intragastric pressure (IGP) was measured for 1 h. Protocol 2 (n = 10, 24.3 ± 0.8 years, 22.3 ± 0.9 kg/m² ): 60 min after treatment, HVs consumed one nutrient drink (300 kcal). Thirty minutes thereafter, HVs ate ad libitum from a free-choice buffet for 30 min. Blood was collected at several time points to measure active GLP-1 plasma levels.

RESULTS

During the first 20 min after nutrient infusion, the drop in IGP was smaller after vildagliptin compared to placebo (treatment-by-time interaction effect: P = 0.008). No differences were seen on epigastric symptom scores. Planned contrast analysis showed that active GLP-1 levels were higher after vildagliptin compared to placebo (P = 0.018) only after nutrient ingestion. Total food intake (316.38 ± 58.89 g vs 399.58 ± 63.02 g, P = 0.359) and total caloric intake (594.77 ± 115.17 kcal vs 742.77 ± 107.10 kcal, P = 0.371) did not differ between treatments.

CONCLUSIONS

Vildagliptin inhibits gastric accommodation without affecting epigastric symptom scoring in HVs. Active GLP-1 plasma levels were increased after vildagliptin treatment, but the increase was not sufficient to affect ad libitum food intake. The study was registered at Clincialtrials.gov (NCT 03500900).

GI Motility Testing: Stomach, Small Bowel, and Colon

Symptoms of abdominal pain, nausea, vomiting, bloating, abdominal distention, diarrhea, and constipation are common and may relate to abnormalities in gastrointestinal motility. There are a number of different options to study gastrointestinal motility. This article reviews novel and standard motility tests available in the stomach, small bowel, and colon. The indications for testing, technical details, advantages, and disadvantages of each test will be summarized.

Plausibility criteria for putative pathophysiological mechanisms in functional gastrointestinal disorders: a consensus of experts

BACKGROUND AND AIMS

The functional gastrointestinal disorders (FGIDs) are extremely common conditions associated with a considerable personal, social and health economic burden. Managing FGIDs in clinical practice is challenging because of the uncertainty of symptom-based diagnosis, the high frequency of overlap between these conditions and the limited efficacy of available therapies. It has often been argued that successful drug development and management of FGIDs requires knowledge of the underlying pathophysiology. Numerous and highly variable candidate pathophysiological mechanisms have been implicated in the generation of FGID symptoms, but there is no current consensus on how to best define the relevance of these disturbances.

METHODS

A group of international experts on FGIDs developed plausibility criteria that should be fulfilled by relevant pathophysiological mechanisms in FGIDs.

RESULTS

Five criteria are proposed: (1) the presence of the abnormality in a subset of patients, (2) temporal association between proposed mechanism and symptom(s), (3) correlation between the level of impairment of the mechanism and symptom(s), (4) induction of the symptom(s) by provoking the pathophysiological abnormality in healthy subjects and (5) treatment response by a therapy specifically correcting the underlying disorder or congruent natural history of symptoms and dysfunction in the absence of specific therapy. Based on strength of evidence for these five criteria according to the Grading of Recommendations Assessment, Development and Evaluation system, a plausibility score can be calculated for each mechanism.

CONCLUSION

Evaluation of the strength of evidence for candidate pathophysiological abnormalities fulfilling these five plausibility criteria will help to identify the most relevant mechanisms to target for novel diagnostic approaches and for the development of new therapies.

The effect of sildenafil on gastric motility and satiation in healthy controls

Sildenafil induces relaxation of smooth muscle cells by blocking PDE5. Dyspepsia is one of sildenafil's most frequently reported adverse events, suggesting its effect on gastric motility. Our aim was to study the effect of sildenafil on gastric accommodation (GA) and gastric emptying (GE) in healthy volunteers (HVs).

Methods

Sildenafil (50 mg) or placebo was randomly administered to 16 blinded HVs. After a manometry probe and an infusion catheter were positioned in the proximal stomach, the intragastric pressure (IGP) was measured before and during nutrient drink infusion (ND, 60 ml/min). HVs were asked to score their hunger, satiation and six epigastric symptoms at five-minute intervals. The experiment ended when the HVs scored maximal satiation during ND infusion at one-minute intervals. To assess GE, breath samples were collected every 15 minutes for six hours after the meal (244 kcal).

Results

ND infusion induced a drop in proximal stomach IGP, which was suppressed by sildenafil (average area under the curve for sildenafil: -33.6 ± 8.8 mmHg; placebo: -60.8 ± 11.3 mmHg, p = 0.005). Sildenafil-treated volunteers reached earlier maximal satiation compared to placebo (678 ± 70 ml vs. 836 ± 82.6 ml, p = 0.019). Finally, GE was significantly slower after sildenafil (90.6 ± 5.9 min vs. 76.6 ± 7.1 min, p = 0.04).

Conclusion

Sildenafil inhibits GA, leading to significantly decreased nutrient tolerance, and slightly delays the GE rate in humans.

Effect of Liraglutide Treatment on Jejunostomy Output in Patients With Short Bowel Syndrome: An Open-Label Pilot Study

BACKGROUND

An impaired hormonal "ileo-colonic brake" may contribute to rapid gastric emptying, gastric hypersecretion, high ostomy losses, and the need for parenteral support in end-jejunostomy short bowel syndrome (SBS) patients with intestinal failure (IF). Liraglutide, a glucagon-like peptide 1 receptor agonist, may reduce gastric hypersecretion and dampen gastric emptying, thereby improving conditions for intestinal absorption.

MATERIALS AND METHODS

In an 8-week, open-label pilot study, liraglutide was given subcutaneously once daily to 8 end-jejunostomy patients, aged 63.4 ± 10.9 years (mean ± SD) and with small bowel lengths of 110 ± 66 cm. The 72-hour metabolic balance studies were performed before and at the end of treatment. Food intake was unrestricted. Oral fluid intake and parenteral support volume were kept constant. The primary end point was change in the ostomy wet weight output.

RESULTS

Liraglutide reduced ostomy wet weight output by 474 ± 563 g/d from 3249 ± 1352 to 2775 ± 1187 g/d (P = .049, Student t test). Intestinal wet weight absorption tended to increase by 464 ± 557 g/d (P = .05), as did urine production by 765 ± 759 g/d (P = .02). Intestinal energy absorption improved by 902 ± 882 kJ/d (P = .02).

CONCLUSION

Liraglutide reduced ostomy wet weight output in end-jejunostomy patients with SBS-IF and increased their intestinal wet weight and energy absorption. If larger, randomized, placebo-controlled studies confirm these effects, it adds to the hypothesis that many ileo-colonic brake hormones in conjunction may be involved in the process of intestinal adaptation. By identification of key hormones and addressing their potential synergistic effects, better treatments may be provided to patients with SBS-IF. This trial was registered at clinicaltrialsregister.eu as 2013-005499-16.

The effect of mirtazapine on gastric accommodation, gastric sensitivity to distention, and nutrient tolerance in healthy subjects

BACKGROUND

Disturbances of gastric motor function of functional dyspepsia (FD) have been implicated in the pathogenesis of the symptoms, and hence, motility modifying agents are considered for its treatment. Mirtazapine was recently shown to improve symptoms and increase nutrient tolerance in FD patients with weight loss. We aim to evaluate the effect of mirtazapine on gastric sensorimotor function in healthy volunteers (HV).

METHODS

Thirty-one HV underwent an intragastric pressure (IGP) and barostat measurements on separate days before and after 3 weeks of placebo or mirtazapine (15 mg). Gastric compliance, sensitivity and accommodation (GA) measured by the barostat. GA was quantitated as the difference (delta) in intra-balloon volume before and after ingestion of 200 mL of a nutrient drink (ND). GA measured by IGP was quantitated as the drop of IGP from baseline during the intragastric infusion of ND until maximal satiation.

KEY RESULTS

Mirtazapine significantly increased the bodyweight of subjects (67.8±3.7 to 69.1±3.7 kg; P=.01). Barostat results showed no effect on gastric compliance, sensitivity, and GA. Nutrient tolerance was not affected after treatment (1170±129.4 vs 1104±133.6 kcal; P=.4), and mirtazapine was associated with lower symptom ratings. The IGP drop during meal ingestion was significantly suppressed (area under the curve: -43.3±4.5 mm Hg vs -28.9±3.1 mm Hg; P=.005).

CONCLUSIONS & INFERENCES

In HVs, the occurrence of weight gain and decreased meal-induced symptoms in spite of a suppressed meal-induced IGP drop, point towards a central mode of action. Mirtazapine does not display changes in gastric sensorimotor function that could explain its beneficial effects on symptoms and nutrient tolerance in FD.

Effects of liraglutide on weight, satiation, and gastric functions in obesity: a randomised, placebo-controlled pilot trial

BACKGROUND

Liraglutide, a long-acting GLP-1 receptor agonist, is approved for treatment of obesity; however, the mechanisms of action of liraglutide are incompletely understood. We compared effects of liraglutide versus placebo on gastric motor functions, satiation, satiety, and weight in obese individuals over 16 weeks.

METHODS

We did a randomised, double-blind, placebo-controlled pilot trial at a single centre (Mayo Clinic, Rochester, MN, USA). Participants were randomly allocated (1:1) by a computer generated randomisation schedule with no stratification to receive subcutaneous liraglutide (3·0 mg) or placebo, with standardised nutritional and behavioural counselling. Allocation was concealed from participants and study investigators. Otherwise healthy, local residents aged 18-65 years with body-mass index (BMI) 30 kg/m² or higher were included. Liraglutide or placebo was escalated by 0·6 mg/day each week for 5 weeks and continued until week 16. The primary outcome was change in gastric emptying (delay relative to baseline) of solids T_1/2 (time taken for half the radiolabelled meal to empty from the stomach), measured at 5 weeks and 16 weeks in all patients who received at least one dose of study drug, with missing data imputed. Secondary outcomes included weight loss at weeks 5 and 16, satiation (volume to fullness and maximum tolerated volume), satiety, and fasting and postprandial gastric volumes at 16 weeks. This trial is registered with ClinicalTrials.gov, number NCT02647944, and is closed to new participants.

FINDINGS

Between Dec 18, 2015, and Sept 1, 2016, 40 adults were enrolled and randomly allocated (19 to the liraglutide group; 21 to the placebo group). Compared with placebo, liraglutide delayed gastric emptying of solids at 5 weeks (median 70 min [IQR 32 to 151] vs 4 min [-21 to 18]; p<0·0001) and 16 weeks (30·5 min [-11 to 54] vs -1 min [-19 to 7]; p=0·025). There was also significantly greater weight loss in the liraglutide group than in the placebo group (at 5 weeks: median 3·7 kg [IQR 2·8 to 4·8] vs 0·6 kg [-0·3 to 1·4], p<0·0001; at 16 weeks: 5·3 kg [5·2 to 6·8] vs 2·5 kg [0·1 to 4·2], p=0·0009). Satiation, as assessed by maximum tolerated volume at 16 weeks, was lower in the liraglutide group (median 750 mL [IQR 651 to 908]) compared with the placebo group (1126 mL [944-1185]; p=0·054). No significant differences were noted between groups in terms of volume to fullness, satiety, or fasting and postprandial gastric volumes at week 16. Post-hoc analysis showed that the T_1/2 of gastric emptying of solids at 5 weeks correlated with change in weight loss at week 16 with liraglutide (Rs 0·567, p=0·018). Nausea was the most common adverse event in the liraglutide group (12 of 19) compared with placebo (four of 21).

INTERPRETATION

Effects of liraglutide on weight loss are associated with delay in gastric emptying of solids; measurement of gastric emptying (eg, at 5 weeks of treatment) may be a biomarker of responsiveness and may help to select individuals for prolonged treatment with this class of drug.

FUNDING

US National Institutes of Health grant R56-DK67071.

The Intragastric Pressure Measurement: A Novel Method to Assess Gastric Accommodation in Functional Dyspepsia Children

BACKGROUND

Impaired gastric accommodation (GA) is proposed as a main pathophysiological mechanism for functional dyspepsia (FD). At present, the gastric barostat is the criterion standard to measure GA. Hence, this procedure is invasive and it may alter gastric physiology. Recently, we proposed the measurement of intragastric pressure (IGP) by means of high-resolution manometry during nutrient intake as a potential alternative for assessing GA in adults.

OBJECTIVES

Our aim was first to study the feasibility of the IGP measurement with nutrient tolerance in children with FD and second to compare these results with young healthy adults.

METHODS

A high-resolution manometry probe and a feeding tube were positioned in the proximal stomach. The IGP was measured before and during intragastric infusion of a nutrient drink (ND, 300 kcal, 60 mL/min). Subjects were asked to score their satiation and epigastric symptoms. The test ended when the subjects scored maximal satiation.

RESULTS

A total of 15 healthy volunteers (HVs, 21.7 ± 4.7 years, 21.1 ± 0.3 kg/m) and 17 patients with FD (14.4 ± 0.7 years, 19.6 ± 0.7 kg/m) participated. Patients with FD experienced mainly from postprandial fullness (86%), epigastric pain (71%), and bloating (62%). In both groups, intragastric infusion of ND induced a drop in IGP (area above the IGP curve FD: -15.5 ± 3.5 mmHg vs HVs: -18.0 ± 8.7 mmHg; P = 0.57). Patients showed impaired nutrient tolerance compared with HVs (587.6 ± 80.2 vs 936 ± 66.2 kcal; P = 0.003). All patients and HVs tolerated the catheters and could finalize the study.

CONCLUSIONS

The measurement of IGP during intragastric ND infusion was well tolerated in children. Nutrient tolerance was reduced in children with FD compared with HVs. In the future, this may be a useful tool to assess GA accommodation and nutrient tolerance in children.

Measurement of Gastrointestinal and Colonic Motor Functions in Humans and Animals

Accurately measuring the complex motor behaviors of the gastrointestinal tract has tremendous value for the understanding, diagnosis and treatment of digestive diseases. This review synthesizes the literature regarding current tests that are used in both humans and animals. There remains further opportunity to enhance such tests, especially when such tests are able to provide value in both the preclinical and the clinical settings.

GLP-1 based therapies: clinical implications for gastroenterologists

The gut-derived incretin hormone, glucagon-like peptide 1 (GLP-1) lowers postprandial blood glucose levels by stimulating insulin and inhibiting glucagon secretion. Two novel antihyperglycaemic drug classes augment these effects; GLP-1 receptor agonists and inhibitors of the GLP-1 degrading enzyme dipeptidyl peptidase 4. These so called GLP-1 based or incretin based drugs are increasingly used to treat type 2 diabetes, because of a low risk of hypoglycaemia and favourable effect on body weight, blood pressure and lipid profiles. Besides glucose control, GLP-1 functions as an enterogastrone, causing a wide range of GI responses. Studies have shown that endogenous GLP-1 and its derived therapies slow down digestion by affecting the stomach, intestines, exocrine pancreas, gallbladder and liver. Understanding the GI actions of GLP-1 based therapies is clinically relevant; because GI side effects are common and need to be recognised, and because these drugs may be used to treat GI disease.

The stomach in health and disease

The stomach is traditionally regarded as a hollow muscular sac that initiates the second phase of digestion. Yet this simple view ignores the fact that it is the most sophisticated endocrine organ with unique physiology, biochemistry, immunology and microbiology. All ingested materials, including our nutrition, have to negotiate this organ first, and as such, the stomach is arguably the most important segment within the GI tract. The unique biological function of gastric acid secretion not only initiates the digestive process but also acts as a first line of defence against food-borne microbes. Normal gastric physiology and morphology may be disrupted by Helicobacter pylori infection, the most common chronic bacterial infection in the world and the aetiological agent for most peptic ulcers and gastric cancer. In this state-of-the-art review, the most relevant new aspects of the stomach in health and disease are addressed. Topics include gastric physiology and the role of gastric dysmotility in dyspepsia and gastroparesis; the stomach in appetite control and obesity; there is an update on the immunology of the stomach and the emerging field of the gastric microbiome. H. pylori-induced gastritis and its associated diseases including peptic ulcers and gastric cancer are addressed together with advances in diagnosis. The conclusions provide a future approach to gastric diseases underpinned by the concept that a healthy stomach is the gateway to a healthy and balanced host. This philosophy should reinforce any public health efforts designed to eradicate major gastric diseases, including stomach cancer.

GLP-1: benefits beyond pancreas

INTRODUCTION

Glucagon-like peptide 1 (GLP-1) is an intestinal hormone secreted after the ingestion of various nutrients. The main role of GLP-1 is to stimulate insulin secretion in a glucose-dependent manner. However, the expression of GLP-1 receptor was found to be expressed in a variety of tissues beyond pancreas such as lung, stomach, intestine, kidney, heart and brain. Beyond pancreas, a beneficial effect of GLP-1 on body weight reduction has been shown, suggesting its role for the treatment of obesity. In addition, GLP-1 has been demonstrated to reduce cardiovascular risk factors and to have a direct cardioprotective effect, fostering heart recovery after ischemic injury. Further, data from both experimental animal models and human studies have shown beneficial effect of GLP-1 on bone metabolism, either directly or indirectly on bone cells.

MATERIALS AND METHODS

We review here the recent findings of the extra-pancreatic effects of GLP-1 focusing on both basic and clinical studies, thus opening future perspectives to the use of GLP-1 analogs for the treatment of disease beyond type 2 diabetes.

CONCLUSION

Finally, the GLP-1 has been demonstrated to have a beneficial effect on both vascular, degenerative diseases of central nervous system and psoriasis.

Effect of dietary macronutrients on postprandial incretin hormone release and satiety in obese and normal-weight women

The aim of the present study was to assess the effect of dietary macronutrients on postprandial incretin responses and satiety and hunger sensation in obese and normal-weight women. A total of eleven obese and nine normal-weight women were recruited for the assessment of plasma concentrations of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and insulin and the sensation of satiety and hunger using a visual analogue scale before and during a 6 h period after administration of three different macronutrient test meals. The AUCtotalGLP-1 and AUCtotalGIP values were decreased in obese women after the consumption of a fatty meal and all the test meals, respectively. However, the AUCtotal insulin value after a carbohydrate meal was greater in the obese group. The AUCtotal satiety value was decreased only after the intake of the protein meal in obese women when compared with normal-weight women. After the consumption of the fatty meal, a significant positive correlation between maximum satiety sensation and the AUCtotal GLP-1 value in the obese group and that between minimum hunger sensation and the AUCtotal GLP-1 value in the normal-weight group were observed. In conclusion, the findings of the present study suggest that: (1) satiety sensation after consumption of carbohydrate and protein meals in the obese group is related to the postprandial insulin response, while after consumption of a fatty meal, it is related to the postprandial GLP-1 release; (2) the postprandial GIP response does not influence the sensation of satiety and hunger; (3) the reduced GLP-1 release after the intake of a fatty meal in obese individuals may explain impaired satiety sensation; (4) the impaired postprandial GIP response is not related to the consumption of macronutrients and may be the early indicator of incretin axis dysfunction in obese women.