Effects of GLP-1 and Its Analogs on Gastric Physiology in Diabetes Mellitus and Obesity

The processing of proglucagon in intestinal L cells results in the formation of glucagon, GLP-1, and GLP-2. The GLP-1 molecule becomes active through the effect of proconvertase 1, and it is inactivated by dipeptidyl peptidase IV (DPP-IV), so that the half-life of endogenous GLP-1 is 2-3 min. GLP-1 stimulates insulin secretion from β cells in the islets of Langerhans. Human studies show that infusion of GLP-1 results in slowing of gastric emptying and increased fasting and postprandial gastric volumes. Retardation of gastric emptying reduces postprandial glycemia. Exendin-4 is a peptide agonist of the GLP-1 receptor that promotes insulin secretion. Chemical modifications of exendin-4 and GLP-1 molecules have been accomplished to prolong the half-life of GLP-1 agonists or analogs. This chapter reviews the effects of GLP-1-related drugs used in treatment of diabetes or obesity on gastric motor functions, chiefly gastric emptying. The literature shows that diverse methods have been used to measure effects of the GLP-1-related drugs on gastric emptying, with most studies using the acetaminophen absorption test which essentially measures gastric emptying of liquids during the first hour and capacity to absorb the drug over 4-6 h, expressed as AUC. The most valid measurements by scintigraphy (solids or liquids) and acetaminophen absorption at 30 or 60 min show that GLP-1-related drugs used in diabetes or obesity retard gastric emptying, and this is associated with reduced glycemia and variable effects on food intake and appetite. GLP-1 agonists and analogs are integral to the management of patients with type 2 diabetes mellitus and obesity. The effects on gastric emptying are reduced with long-acting preparations or long-term use of short-acting preparations as a result of tachyphylaxis. The dual agonists targeting GLP-1 and another receptor (GIP) do not retard gastric emptying, based on reports to date. In summary, GLP-1 agonists and analogs are integral to the management of patients with type 2 diabetes mellitus and obesity, and their effects are mediated, at least in part, by retardation of gastric emptying.

Mechanisms of Esophageal and Gastric Transit Following Sleeve Gastrectomy

PURPOSE

Sleeve gastrectomy (SG) patients have substantially altered anatomy. The mechanism of rapid gastric emptying and the role of esophageal contractile function in esophago-gastric transit has not been defined. We aimed to determine the mechanisms of esophago-gastric transit and role of esophageal function following sleeve gastrectomy.

METHODS

Prospective study of twenty-six asymptomatic participants post SG underwent nuclear scintigraphy and high-resolution manometry. Fourteen had semi-solid stress barium to model the emptying process. Concurrent video fluoroscopy and manometry were performed on 7 participants.

RESULTS

Demographic data are as follows: age 45.3 ± 15.0 years, 73.1% female, excess weight loss 62.2 ± 28.1% at 8 months. Scintigraphy showed rapid gastric emptying (24.4 ± 11.4 vs. 75.80 ± 45.19 min in control, p < 0.001) with 35.24 ± 17.12% of bolus transited into small bowel on initial frame. Triggered deglutitive reflux was common (54.4% vs. 18.2%, p = 0.017). Stress barium delineated separate vertical and antral gastric compartments with cyclical emptying of 8 stages, including reflux-induced repeated esophageal peristalsis. During manometry, ramping effects were noted, with sequential swallows producing sustained isobaric pressurizations in proximal stomach (33.6 ± 29.5 mmHg). Video fluoroscopy showed individual esophageal peristalsis generating pressurizations at 5.0 ± 1.4 cm below lower esophageal sphincter (LES), at amplitude of 31.6 ± 13.1 mmHg, associated with intragastric transit. Pressurizations were sustained for 17.3 ± 8.2 s, similar to the prolonged LES contraction (18.5 ± 9.0 s, p = 0.355).

CONCLUSIONS

Repeated esophageal peristaltic contractions induced isobaric pressurization of proximal stomach, thus providing the drive to pressurize and empty the vertical compartment of the gastric sleeve. Transit following SG appeared to be esophageal-mediated and followed a distinct cycle with strong associations with reflux.

Technical emptiability of dairy product packaging and its environmental implications in Austria

BACKGROUND

Food waste is a major ecological concern around the globe. While the main function of packaging is to contain and protect food, it may also lead to food waste if residues remain in a package after emptying. Such residues could be attributed to wasteful behavior of consumers, but also to properties of packaging (e.g., geometry, surface tension) and food (e.g., surface tension, viscosity).

METHODS

In this study, the technical emptiability (ability of packaging to be emptied entirely) of 36 dairy products is analyzed. Firstly, the amount of food residues in packaging after emptying at room and refrigerator temperature was weighed and set in relation to the original filling quantity. Secondly, streamlined life cycle assessments (LCAs) based on the Product Environmental Footprint guidance with a functional unit of "one kg of consumed dairy product at room or refrigerator temperature in the home of the consumer" are conducted. Finally, technical emptiability was included in the streamlined LCA and attributed to the primary packaging in order to evaluate its environmental impact.

RESULTS

Technical emptiability for both temperatures combined was found to be between 0.25% (±0.11) and 5.79% (±0.43) for the analyzed dairy products. While there were differences in emptiability results of the same product and different temperatures, no significant trend (p = 0.94) between emptiability and temperature could be observed. Liquid yogurt, cream, and buttermilk in beverage cartons and plastic bottles yielded the highest amounts, while milk in beverage cartons and glass bottles yielded the lowest amounts regarding food residues. Looking at global warming potential, poor technical emptiability of cream in a beverage carton leads to even higher environmental impacts than the production and waste management of its packaging.

DISCUSSION

The streamlined LCA results show that food residues can contribute substantially to the footprint of packaging and can have similar or even higher environmental impacts than packaging production and waste management. Yet, emptiability is remarkably under-researched to this day. Future studies should further develop the methods presented in this paper, while LCA analysts should include technical emptiability when assessing the sustainability of packaging, particularly for those containing resource-intensive goods.

Association Between Gastric Emptying Time and Incidence of Cardiovascular Diseases in Subjects With Diabetes

Background/Aims

Delayed gastric emptying (GE) is associated with high morbidity and mortality in subjects with diabetes. The aim of this study is to investigate associations between GE time and the major cardiovascular events (coronary heart diseases and ischemic stroke) in diabetic subjects with upper gastrointestinal (UGI) symptoms.

Methods

Among 259 subjects with chronic UGI symptoms who underwent gastric emptying study (GES) over 13 years, 122 diabetic subjects without gastric surgery and/or rapid GE were enrolled in this study. We also gathered data about baseline demographics, clinical characteristics, estimated GE half-time (GE T_½) and incidence of cardiovascular events following GES.

Results

The mean age of subjects was 64.0 ± 17.4 years. There were 86 women and 104 subjects with type 2 diabetes. There were 52 (42.6%) subjects with normal GE, 50 (41.0.%) subjects with mild delayed GE, and 20 (16.4%) subjects with marked delayed GE. During follow-up (median, 207 weeks), cardiovascular events occurred in 7 (13.5%) subjects with normal GE, 4 (8.0%) subjects with mild delayed GE and 7 (35.0%) subjects with marked GE (P = 0.015). Univariate analysis showed that GE T_½ was significantly associated with incidence of cardiovascular events (crude OR, 1.74; 95% CI, 1.12–2.69; P = 0.014). In a multivariate model, association between GE T_½ and incidence of cardiovascular events remained statistically significant after adjustment for baseline characteristics and comorbidities (adjusted OR, 1.94; 95% CI, 1.21–3.12; P = 0.006).

Conclusion

A delay of GE was associated with an increased incidence of cardiovascular events in diabetic subjects with chronic UGI symptoms.

Effect of Laparoscopic-assisted Gastropexy on Gastrointestinal Transit Time in Dogs

Background

Prophylactic gastropexy has been promoted as a means of preventing gastric volvulus during gastric dilatation and volvulus (GDV) syndrome. Little is known about the impact of gastropexy on gastrointestinal transit time.

Hypothesis

Laparoscopic‐assisted gastropexy (LAG) will not alter gastrointestinal transit times when comparing gastric (GET), small and large bowel (SLBTT), and whole gut transit times (TTT) before and after surgery.

Animals

10 healthy client‐owned large‐breed dogs.

Methods

Prospective clinical trial. Before surgery, all dogs underwent physical examination and diagnostic evaluation to ensure normal health status. Dogs were fed a prescription diet for 6 weeks before determination of gastrointestinal transit with a wireless motility capsule. LAG was then performed, and dogs were fed the diet for 6 additional weeks. Measurement of transit times was repeated 6 weeks after surgery.

Results

Ten dogs of various breeds at‐risk for GDV were enrolled. No complications were encountered associated with surgery or capsule administration. There were no significant differences in GET 429 [306–1,370] versus 541 [326–1,298] (P = 0.80), SLBTT 1,243 [841–3,070] versus 1,540 [756–2,623] (P = 0.72), or TTT 1,971 [1,205–3,469] versus 1,792 [1,234–3,343] minutes (median, range) (P = 0.65) before and after LAG.

Conclusions and Clinical Importance

An effect of LAG on gastrointestinal transit time was not identified, and wireless motility capsule can be safely administered in dogs after LAG.

Acute effect of smoking on gallbladder emptying and refilling in chronic smokers and nonsmokers: A sonographic study

AIM: To ultrasonographicaly evaluate the acute effects of smoking on gallbladder contraction and refilling in chronic smokers and nonsmokers.

METHODS: Fifteen chronic smokers (21-30 years old) and fifteen nonsmokers (21-35 years old) participated in this study. Chronic smokers were selected among the volunteers who had been smoking for at least 5 years and 10 cigarettes per day (mean 17.5/d). Examinations were performed in two separate days. In the first day, basal gallbladder (GB) volumes of volunteers were measured after 8-h fasting. After the examinations, participants had a meal containing at least 30-40 gram fat. Gallbladder volume was assessed at 5, 15, 30, 60, 120 and 180 min after the meal. In the second day, participants smoked 2 cigarettes after 8-h fasting. Then, they had the same meal, and gallbladder measurements were repeated at the same time points. Same procedures were applied to both groups.

RESULTS: The mean starving GB volumes were 23.3 ± 3.3 mL in the first day, 21.9 ± 3.0 mL in the second day in nonsmoker group and 18.3 ± 3.0 mL in the first day, 19.5 ± 2.8 mL in second day in smoker group. There was no significant difference between starving GB volumes. We did not find any significant difference between the GB volumes measured at 5, 15, 30, 60, 120 and 180 min in the first and second days in nonsmoker group. In smokers, post cigarette GB volume was found significantly higher at 5, 15 and 30 min which corresponded to GB contraction phase (P < 0.05). Control GB volume measurements were not significantly different between the two groups. Post-smoking GB volumes were also not significantly different between the two groups.

CONCLUSION: Smoking prolongs the maximal GB emptying time both in smokers and in nonsmokers though it is not significant. It delays GB contraction in chronic smokers and causes a significant decrease in GB emptying volume. Smoking causes no significant delay in GB refilling in both smokers and nonsmokers. These effects of smoking observed in acute phase result in bile stasis in GB. Bile stasis is the underlying cause of most GB disorders in chronic process.