The stimulation of antral motility by erythromycin is attenuated by hyperglycemia

Inter-relationships between gastric emptying and glycaemia: Implications for clinical practice

Gastric emptying (GE) exhibits a wide inter-individual variation and is a major determinant of postprandial glycaemia in health and diabetes; the rise in blood glucose following oral carbohydrate is greater when GE is relatively more rapid and more sustained when glucose tolerance is impaired. Conversely, GE is influenced by the acute glycaemic environment acute hyperglycaemia slows, while acute hypoglycaemia accelerates it. Delayed GE (gastroparesis) occurs frequently in diabetes and critical illness. In diabetes, this poses challenges for management, particularly in hospitalised individuals and/or those using insulin. In critical illness it compromises the delivery of nutrition and increases the risk of regurgitation and aspiration with consequent lung dysfunction and ventilator dependence. Substantial advances in knowledge relating to GE, which is now recognised as a major determinant of the magnitude of the rise in blood glucose after a meal in both health and diabetes and, the impact of acute glycaemic environment on the rate of GE have been made and the use of gut-based therapies such as glucagon-like peptide-1 receptor agonists, which may profoundly impact GE, in the management of type 2 diabetes, has become commonplace. This necessitates an increased understanding of the complex inter-relationships of GE with glycaemia, its implications in hospitalised patients and the relevance of dysglycaemia and its management, particularly in critical illness. Current approaches to management of gastroparesis to achieve more personalised diabetes care, relevant to clinical practice, is detailed. Further studies focusing on the interactions of medications affecting GE and the glycaemic environment in hospitalised patients, are required.

Diabetic Gastroparesis

This review covers the epidemiology, pathophysiology, clinical features, diagnosis, and management of diabetic gastroparesis, and more broadly diabetic gastroenteropathy, which encompasses all the gastrointestinal manifestations of diabetes mellitus. Up to 50% of patients with type 1 and type 2 DM and suboptimal glycemic control have delayed gastric emptying (GE), which can be documented with scintigraphy, 13C breath tests, or a wireless motility capsule; the remainder have normal or rapid GE. Many patients with delayed GE are asymptomatic; others have dyspepsia (i.e., mild to moderate indigestion, with or without a mild delay in GE) or gastroparesis, which is a syndrome characterized by moderate to severe upper gastrointestinal symptoms and delayed GE that suggest, but are not accompanied by, gastric outlet obstruction. Gastroparesis can markedly impair quality of life, and up to 50% of patients have significant anxiety and/or depression. Often the distinction between dyspepsia and gastroparesis is based on clinical judgement rather than established criteria. Hyperglycemia, autonomic neuropathy, and enteric neuromuscular inflammation and injury are implicated in the pathogenesis of delayed GE. Alternatively, there are limited data to suggest that delayed GE may affect glycemic control. The management of diabetic gastroparesis is guided by the severity of symptoms, the magnitude of delayed GE, and the nutritional status. Initial options include dietary modifications, supplemental oral nutrition, and antiemetic and prokinetic medications. Patients with more severe symptoms may require a venting gastrostomy or jejunostomy and/or gastric electrical stimulation. Promising newer therapeutic approaches include ghrelin receptor agonists and selective 5-hydroxytryptamine receptor agonists.

Diabetic gastroparesis

Gastroparesis is a complication of long-standing type 1 and type 2 diabetes mellitus. Symptoms associated with gastroparesis include early satiety, prolonged postprandial fullness, bloating, nausea and vomiting, and abdominal pain. Mortality is increased in patients with diabetic gastroparesis. A subset of patients with diabetic gastroparesis have pylorospasm that results in obstructive gastroparesis. Current treatment approaches include improving glucose control with insulin and prescribing antinauseant drugs, prokinetic agents, and gastric electric stimulation. Future directions include improved diet counseling based on gastric emptying rate, continuous insulin delivery systems with glucose sensor-augmented monitoring, and drugs for correcting gastric neural and electric abnormalities.

The ghrelin agonist RM-131 accelerates gastric emptying of solids and reduces symptoms in patients with type 1 diabetes mellitus

BACKGROUND & AIMS

RM-131, a synthetic ghrelin agonist, greatly accelerates gastric emptying of solids in patients with type 2 diabetes and delayed gastric emptying (DGE). We investigated the safety and effects of a single dose of RM-131 on gastric emptying and upper gastrointestinal (GI) symptoms in patients with type 1 diabetes and previously documented DGE.

METHODS

In a double-blind cross-over study, 10 patients with type 1 diabetes (age, 45.7 ± 4.4 y; body mass index, 24.1 ± 1.1 kg/m(2)) and previously documented DGE were assigned in random order to receive a single dose of RM-131 (100 μg, subcutaneously) or placebo. Thirty minutes later, they ate a radiolabeled solid-liquid meal containing EggBeaters (ConAgra Foods, Omaha, NE), and then underwent 4 hours of gastric emptying and 6 hours of colonic filling analyses by scintigraphy. Upper GI symptoms were assessed using a daily diary, gastroparesis cardinal symptom index (total GCSI-DD) and a combination of nausea, vomiting, fullness, and pain (NVFP) scores (each rated on a 0-5 scale).

RESULTS

At screening, participants' mean level of hemoglobin A1c was 9.1% ± 0.5%; their total GCSI-DD score was 1.66 ± 0.38 (median, 1.71), and their total NVFP score was 1.73 ± 0.39 (median, 1.9). The t1/2 of solid gastric emptying was 84.9 ± 31.6 minutes when subjects were given RM-131 and 118.7 ± 26.7 when they were given a placebo. The median difference (Δ)was 33.9 minutes (interquartile range [IQR] -12, -49), or -54.7% (IQR, -21%,-110%). RM-131 decreased gastric retention of solids at 1 hour (P = .005) and 2 hours (P = .019). Numeric differences in t1/2 for gastric emptying of liquids, solid gastric emptying lag time, and colonic filling at 6 hours were not significant. Total GCSI-DD scores were 0.79 on placebo (IQR, 0.75, 2.08) and 0.17 on RM-131 (IQR, 0.00, 0.67; P = .026); NVFP scores were lower on RM-131 (P = .041). There were no significant adverse effects.

CONCLUSIONS

RM-131 significantly accelerates gastric emptying of solids and reduces upper GI symptoms in patients with type 1 diabetes and documented DGE.

Treatments for severe gastroparesis

Severe gastroparesis is a kind of gastroparesis that is refractory to conventional drug therapy and requires nutritional support and frequently emergency hospitalization. The selection of treatment for severe gastroparesis has always been a dilemma for clinicians. Currently, there have been limited reports on the treatment of severe gastroparesis. This article sums up the primary treatments, drug treatments and other kinds of treatments for severe gastroparesis and discusses the prospects for the treatment of this refractory disease.

The effect of erythromycin on gastrointestinal motility in subtotal gastrectomized patients

Purpose

Our objective was to determine the effect of erythromycin (EM) in improving gastrointestinal motility in subtotal gastrectomized patients. We used radio-opaque Kolomarks as an objective method. We conducted a prospective, controlled clinical trial study of 24 patients.

Methods

All patients underwent subtotal gastrectomy with 3 capsules containing Kolomarks (20 markers per 1 capsule) in the remnant stomach before anastomosis. From the day of the operation to the 2nd postoperative day, patients in the EM group began receiving 200 mg of EM intravenously for 30 minutes continuously. We counted the number of Kolomarks in the stomach, passed by stomach, in rectum, and in stool with serial simple abdominal X-ray films on the first postoperative day up to the 7th postoperative day.

Results

The study population included 14 patients in the control group and 10 patients in the EM group. The two study groups were compared in terms of their characteristics including age, gender, past medical history, cancer stage, and operation type. No significant differences were found for the demographics between the two groups. We only found a significant difference for the number of Kolomarks passed by the stomach on the 3rd postoperative day (P = 0.026).

Conclusion

Our results demonstrated that 200 mg of EM intravenous infusion during the postoperative period induced rapid gastric emptying, although it did not improve gastrointestinal motility for the entire gastrointestinal tract in subtotal gastrectomized patients.

Nutritional therapy for the management of diabetic gastroparesis: clinical review

Diabetic gastroparesis (DGP), or slow emptying of the stomach, is a well-established complication of diabetes mellitus and is typically considered to occur in individuals with long-standing type 1 and type 2 diabetes mellitus. Clinical consequences of DGP include induction of gastrointestinal (GI) symptoms (early satiety, abdominal distension, reflux, stomach spasm, postprandial nausea, vomiting), alteration in drug absorption, and destabilization of glycemic control (due to mismatched postprandial glycemic and insulin peaks). Effective nutritional management not only helps in alleviating the symptoms, but also in facilitating better glycemic control. Although there have been no evidence-based guidelines pertaining to the nutrition care process of the DGP, the current dietary recommendations are based on expert opinions or observational studies. The dietary management of gastroparesis needs to be tailored according to the severity of malnutrition and kind of upper GI symptom by changing the volume, consistency, frequency, fiber, fat, and carbohydrates in the meal. Small frequent meals, using more liquid calories, reducing high fat or high fiber, consuming bezoar forming foods, and adjusting meal carbohydrates based on medications or insulin helps in improving the upper GI symptoms and glycemic control. Enteral nutrition can be an option for patients who fail to stabilize their weight loss, or for those who cannot gain weight with oral feedings, while total parenteral nutrition is rarely necessary for the patient with gastroparesis.

Glucose control in the intensive care unit: a nutrition support perspective

Hyperglycemia commonly occurs in acutely ill patients who receive nutrition support, even in patients without a history of diabetes. The traditional view that stress hyperglycemia may be a beneficial adaptive response has been replaced by data linking hyperglycemia with increased morbidity and mortality in critically ill populations. Initial randomized studies to control stress hyperglycemia with intensive insulin infusion reported dramatic decreases in infectious complications and decreased mortality. However, recent large multicenter trials have reported that intensive insulin therapy designed to normalize blood glucose resulted in an unacceptable increase in the incidence of hypoglycemia. Review of the methods, protocols, and nutrition provided during these randomized studies is crucial to understanding the different conclusions reached and how these results may be used to influence protocols in intensive care units today. Evidence is reviewed and practical considerations are provided for nutrition support regimens to minimize stress hypoglycemia and assist glucose management.

Diabetic gastroparesis and its impact on glycemia

Diabetes is the most common cause of gastroparesis and it is now recognized that the relationship between gastric emptying and glycemia is complex and intertwined. Postprandial blood glucose levels influence, and are influenced by, the rate of gastric emptying, highlighting the difficulty in determining which is the cause and which is the effect. Novel diagnostic techniques and therapeutic strategies have been developed for the management of diabetic gastroparesis. This article highlights recent advances in knowledge about diabetic gastroparesis, with an emphasis on the inter-relationships between disordered gastric motor function on glycemia and vice versa, as well as therapeutic strategies for optimizing glycemic control using modulation of gastric emptying.

Clinical management of motility disorders in children

We review the current clinical evaluation and management of the most common esophageal and gastrointestinal motility disorders in children based on the literature and our experience in a pediatric motility center in the United States. The disorders discussed include esophageal achalasia, pre- and post-fundoplication motility disorders, gastroparesis, motility disorders occurring after repair of congenital atresias, motility disorders associated with gastroschisis, chronic intestinal pseudo-obstruction, motility after intestinal transplantation, motility disorders after colonic resection for Hirschsprung's disease, chronic functional constipation, and motility disorders associated with imperforate anus.

Pathophysiology and management of gastroparesis

Gastroparesis is characterized by upper gastrointestinal symptoms associated with delayed gastric emptying, without mechanical obstruction. However, symptoms do not correlate well with the magnitude of delay in gastric emptying. Diabetes mellitus and surgery are the most common causes, although more than 30% of cases are idiopathic. Coordination of insulin action with nutrient delivery is important in diabetics, as postprandial blood glucose levels and gastric emptying are interdependent, and gastroparesis probably represents a major cause of poor glycemic control. Scintigraphy is the gold standard for measuring gastric emptying. Current treatment mainly involves the use of prokinetic drugs. Pyloric botulinum toxin injection and gastric electrical stimulation require more evidence from controlled studies before their use can be recommended. Surgical options remain inadequately studied.

Glucose absorption and gastric emptying in critical illness

INTRODUCTION

Delayed gastric emptying occurs frequently in critically ill patients and has the potential to adversely affect both the rate, and extent, of nutrient absorption. However, there is limited information about nutrient absorption in the critically ill, and the relationship between gastric emptying (GE) and absorption has hitherto not been evaluated. The aim of this study was to quantify glucose absorption and the relationships between GE, glucose absorption and glycaemia in critically ill patients.

METHODS

Studies were performed in nineteen mechanically-ventilated critically ill patients and compared to nineteen healthy subjects. Following 4 hours fasting, 100 ml of Ensure, 2 g 3-O-methyl glucose (3-OMG) and 99mTc sulphur colloid were infused into the stomach over 5 minutes. Glucose absorption (plasma 3-OMG), blood glucose levels and GE (scintigraphy) were measured over four hours. Data are mean +/- SEM. A P-value < 0.05 was considered significant.

RESULTS

Absorption of 3-OMG was markedly reduced in patients (AUC240: 26.2 +/- 18.4 vs. 66.6 +/- 16.8; P < 0.001; peak: 0.17 +/- 0.12 vs. 0.37 +/- 0.098 mMol/l; P < 0.001; time to peak; 151 +/- 84 vs. 89 +/- 33 minutes; P = 0.007); and both the baseline (8.0 +/- 2.1 vs. 5.6 +/- 0.23 mMol/l; P < 0.001) and peak (10.0 +/- 2.2 vs. 7.7 +/- 0.2 mMol/l; P < 0.001) blood glucose levels were higher in patients; compared to healthy subjects. In patients; 3-OMG absorption was directly related to GE (AUC240; r = -0.77 to -0.87; P < 0.001; peak concentrations; r = -0.75 to -0.81; P = 0.001; time to peak; r = 0.89-0.94; P < 0.001); but when GE was normal (percent retention240 < 10%; n = 9) absorption was still impaired. GE was inversely related to baseline blood glucose, such that elevated levels were associated with slower GE (ret 60, 180 and 240 minutes: r > 0.51; P < 0.05).

CONCLUSIONS

In critically ill patients; (i) the rate and extent of glucose absorption are markedly reduced; (ii) GE is a major determinant of the rate of absorption, but does not fully account for the extent of impaired absorption; (iii) blood glucose concentration could be one of a number of factors affecting GE.

Noninvasive assessment of the effects of glucagon on the gastric slow wave

Hyperglycemic effects on the gastric slow wave are not well understood, and no studies have examined the effects that hyperglycemia has on gastric slow wave magnetic fields. We recorded multichannel magnetogastrograms (MGGs) before and after intravenous administration of glucagon and subsequent modest hyperglycemia in 20 normal volunteers. Normal slow waves were evident in baseline MGG recordings from all 20 subjects, but within 15 min after glucagon had been given, we noted significant effects on MGG signals. In addition to an overall decrease in the slow wave frequency from 2.9 +/- 0.5 cycles per min (cpm) to 2.2 +/- 0.1 cpm (P < 0.05), we observed significant changes in the number and range of spectral peaks recorded. Furthermore, the propagation velocity determined from surface current density maps computed from the multichannel MGG decreased significantly (7.1 +/- 0.8 mm/s to 5.0 +/- 0.3 mm/s, P < 0.05). This is the first study of biomagnetic effects of hyperglycemia in normal subjects. Our results suggest that the analysis of the MGG provides parameter quantification for gastric electrical activity specific to and characteristic of slow wave abnormalities associated with increased serum glucose by injection of glucagon.

Quantification of distal antral contractile motility in healthy human stomach with magnetic resonance imaging

PURPOSE

To quantify healthy postprandial: 1) propagation, periodicity, geometry, and percentage occlusion by distal antral contraction waves (ACWs); and 2) changes in ACW activity in relationship to gastric emptying (GE).

MATERIALS AND METHODS

Using 1.5-T MR scanner, nine healthy fasted volunteers were examined in the right decubitus position after ingestion of 500 mL of 10% glucose (200 kcal) with 500 microM Gd-DOTA. Total gastric (TGV) and meal volumes (MV) were assessed every five minutes for 90 minutes, in and interspersed with dynamic scan sequences (duration: 2.78 minutes) providing detailed images of distal ACWs.

RESULTS

TGV increased by 738+/-38 mL after ingestion (t0), subsequently decreasing in parallel to GE. The mean GE rate and half-emptying time were 24+/-3 mL/5 minutes and 71+/-6 minutes, respectively. Accompanying ACWs reached a periodicity of 23+/-2 seconds at t35 and propagated at an unvarying speed of 0.27+/-0.01 cm/second. Their amplitude of 0.70+/-0.08 cm was constant, but the width decreased along the antral wall by 6+/-2%/cm (P=0.003). ACWs were nonocclusive (percentage occlusion 58.1+/-5.9%, t0 at the pylorus) with a reduction in occlusion away from the pylorus (P<0.001). No propagation and geometry characteristics of ACWs correlated with the changes of MV (mL/5 minutes; R2<0.05).

CONCLUSION

Our results indicate that ACWs are not imperative for emptying of liquids. This study provides a detailed quantitative reference for MRI inquiries into pharmacologically- and pathologically-altered gastric motility.

Upper gastrointestinal function and glycemic control in diabetes mellitus

Recent evidence has highlighted the impact of glycemic control on the incidence and progression of diabetic micro- and macrovascular complications, and on cardiovascular risk in the non-diabetic population. Postprandial blood glucose concentrations make a major contribution to overall glycemic control, and are determined in part by upper gastrointestinal function. Conversely, poor glycemic control has an acute, reversible effect on gastrointestinal motility. Insights into the mechanisms by which the gut contributes to glycemia have given rise to a number of novel dietary and pharmacological strategies designed to lower postprandial blood glucose concentrations.

The treatment of diabetic gastroparesis with botulinum toxin injection of the pylorus

OBJECTIVE

Gastroparesis is a disorder of delayed gastric emptying that is often chronic in nature. Up to 50% of type 1 diabetic subjects have symptoms of gastroparesis, which include nausea, vomiting, and early satiety. Elevated pyloric pressures may be responsible for delayed gastric emptying in diabetic subjects. Botulinum toxin inhibits the release of acetylcholine and produces transient paralysis when injected into smooth muscle. The aim of this study was to determine whether injection of the pylorus with botulinum toxin in patients with diabetic gastroparesis improves symptoms of gastroparesis, alters gastric emptying scan time, and/or changes weight and insulin use.

RESEARCH DESIGN AND METHODS

This was an open-label trial with age- and sex-matched control subjects from a tertiary care referral center for patients with gastroparesis. Eight type 1 diabetic subjects (six women and two men; mean age 41 years; mean years with diabetes 25.3) who had failed standard therapy were enrolled. Intervention consisted of injection of the pylorus with 200 units of botulinum toxin during upper endoscopy. Symptoms, antropyloric manometry, gastric emptying scan times, weight, and insulin use were all recorded before intervention and during a 12-week follow-up period.

RESULTS

Seven of the eight patients completed the full 12-week follow-up period. No complications were noted. Mean symptom scores declined from 27 to 12.1 (P < 0.01), whereas the SF-36 physical functioning domain also improved (P < 0.05). Four patients noted an increase in insulin use of >5 units/day. Six of the seven patients gained weight (P = 0.05). Gastric emptying scan time improved in four patients.

CONCLUSIONS

Botulinum toxin injection of the pylorus is safe and improves symptoms in patients with diabetic gastroparesis. These results warrant further investigation with a large, double-blind, placebo-controlled trial.

Effect of the motilin agonist KC 11458 on gastric emptying in diabetic gastroparesis

BACKGROUND

KC 11458, a motilin agonist without antibiotic properties, accelerates gastric emptying in animals and healthy humans.

AIM

To evaluate the acute effects of KC 11458 on gastric emptying in diabetic gastroparesis.

METHODS

Twenty-nine patients (6 type 1 and 23 type 2) with gastroparesis underwent assessments of: (i) gastric emptying of a solid/liquid meal using scintigraphy, (ii) glycaemic control (blood glucose at 0, 30, 60, 90 and 120 min during the gastric emptying measurement) and (iii) upper gastrointestinal and 'meal-related' symptoms (questionnaire), at baseline and after treatment with KC 11458 in a dose of 8 mg t.d.s., or placebo for 8 days.

RESULTS

KC 11458 had no statistically significant or clinically relevant effect on gastric emptying of either the solid intragastric retention at 100 min (T100) (P = 0.87) or liquid 50% emptying time (T50) (P = 0.17) components of the meal. KC 11458 slightly worsened (P = 0.04) upper gastrointestinal symptoms when compared with placebo. The magnitude of the change in solid gastric emptying correlated with the change in the blood glucose concentration (r = 0.49; P < 0.05).

CONCLUSIONS

KC 11458, in a dose of 8 mg t.d.s. for 8 days, does not accelerate gastric emptying in patients with diabetic gastroparesis. The absence of efficacy may relate to an effect of hyperglycaemia.

Predictors of delayed gastric emptying in diabetes

OBJECTIVE

To define the predictors of the rate of gastric emptying in patients with diabetes.

RESEARCH DESIGN AND METHODS

A total of 101 outpatients with diabetes (79 type 1 and 22 type 2) underwent measurements of gastric emptying of a solid/liquid meal (scintigraphy), upper gastrointestinal symptoms (questionnaire), glycemic control (blood glucose concentrations during gastric emptying measurement), and autonomic nerve function (cardiovascular reflexes).

RESULTS

The gastric emptying of solid and/or liquid was delayed in 66 (65%) patients. Solid (retention at 100 min 64 +/- 3.2 vs. 50.2 +/- 3.6%, P < 0.005) and liquid (retention at 100 min 22.7 +/- 1.7 vs. 16.0 +/- 1.8%, P < 0.001) gastric emptying was slower in women than in men. Of all upper gastrointestinal symptoms (including nausea and vomiting), only abdominal bloating/fullness was associated with slower gastric emptying (P < 0.005). A multiple regression analysis demonstrated that both abdominal bloating/fullness and female sex were predictors of slower gastric emptying of both solids and liquids.

CONCLUSIONS

We conclude that the presence of abdominal bloating/fullness but not any other upper gastrointestinal symptom is associated with diabetic gastroparesis and that gastric emptying is slower in diabetic women than in diabetic men.

Relationships of upper gastrointestinal motor and sensory function with glycemic control

Acute changes in the blood glucose concentration have a major reversible effect on esophageal, gastric, intestinal, gallbladder, and anorectal motility in both healthy subjects and diabetic patients. For example, gastric emptying is slower during hyperglycemia than euglycemia and accelerated during hypoglycemia. Acute hyperglycemia also affects perceptions arising from the gastrointestinal tract and may accordingly, be important in the etiology of gastrointestinal symptoms in diabetes. Elevations in blood glucose that are within the normal postprandial range also affect gastrointestinal motor and sensory function. Upper gastrointestinal motor function is a critical determinant of postprandial blood glucose concentrations by influencing the absorption of ingested nutrients. Interventions that reduce postprandial hyperglycemia, by modulating the rate of gastric emptying, have the potential to become mainstream therapies in the treatment of diabetes.