Autonomic neuropathy and gastrointestinal motility disorders in children and adolescents with type 1 diabetes mellitus

13 C-gastric emptying breath tests: Clinical use in adults and children

¹³ C-gastric emptying breath tests (¹³ C-GEBT) are validated, reliable, and non-invasive tools for measurement of gastric emptying (GE) velocity of solids and liquids without radiation exposure or risk of toxicity. They are recommended and routinely used for clinical purposes in adult as well as pediatric patients and can be readily performed onsite or even at the patient's home. However, the underlying methodology is rather complex and test results can be influenced by dietary factors, physical activity, concurrent diseases, and medication. Moreover, epidemiological factors can influence gastric emptying as well as production and exhalation of ¹³ CO₂ , which is the ultimate metabolic product measured for all ¹³ C-breath tests. Accordingly, in this issue of Neurogastroenterology & Motility, Kovacic et al. report performance of the ¹³ C-Spirulina breath test in a large group of healthy children and show significant effects of gender, pubertal status, and body size on test results. The purpose of this mini-review is to evaluate the clinical use of ¹³ C-GEBT in adults and children, exploring available protocols, analytical methods, and essential prerequisites for test performance, as well as the role of GE measurements in the light of the current discussion on relevance of delayed GE for symptom generation.

Gastric emptying in children with type 1 diabetes mellitus: A pilot study

AIM

Delayed gastric emptying (GE) has been demonstrated in adults with type 1 diabetes mellitus (T1DM). Little is known about GE in children with T1DM. Most methods to measure GE are invasive, that is, scintigraphy, or are only indirectly related to GE, that is, electrogastrography. Carbon-13 breath testing is a non-invasive, very low-risk procedure that accurately correlates with GE time. This was a pilot study to determine the feasibility of using carbon-13 breath testing to measure GE in children with T1DM and healthy controls.

METHODS

Cases were recruited from children aged 7-15 years presenting to the paediatric diabetic clinic at Christchurch Hospital. Controls were peers of the cases. Children with known gastrointestinal disease were excluded. After an overnight fast, each child ate a standardised pancake labelled with carbon-13 sodium octanoate. Samples of breath were collected over a 4-h period. Samples were analysed by mass spectrometry. GE half time (GET_1/2 ) and GE coefficients (GEC) were calculated by linear regression to obtain a measure of GE.

RESULTS

A total of 19 cases and 15 age- and gender-matched controls underwent testing. The mean GEC in the cases was 3.19 (±0.38) and 2.90 (±0.29) in controls (P = 0.03), with an effect size = 0.86. Mean GET_1/2 in the cases was 99 (52.1) min and 103 (27.5) in controls (P = 0.8), with an effect size = 0.1.

CONCLUSION

The study generated results suggesting that a larger study will be worthwhile to investigate the relationship between GE and T1DM.

Targeting postprandial glycaemia in children with diabetes: Opportunities and challenges

Postprandial glycaemia makes a substantial contribution to overall glycaemic control in diabetes, particularly in patients whose preprandial glycaemia is relatively well controlled and glycated haemoglobin (HbA1c) only modestly elevated. Our review addresses the determinants of postprandial glycaemia and how it may be targeted therapeutically in children with diabetes. Postprandial glycaemia is influenced by preprandial glycaemia, macronutrients and their absorption, insulin delivery and sensitivity, the action of the enteroendocrine system, and the rate of gastric emptying. Contemporary continuous glucose monitoring systems reveal patterns of post prandial glycaemia and allow management to be guided more precisely. Delays in blood glucose determination, insulin delivery and its absorption remain challenges in the rapidly evolving closed loop continuous subcutaneous insulin and glucagon delivery systems developed for children with type 1 diabetes. Augmentation of the incretin system through nutritional preloads or incretin mimetics targets postprandial glycaemia by slowing gastric emptying as well as insulinotropic and glucagonostatic effects. These treatments are of particular relevance to children with type 2 diabetes. Following the development of targeted therapies in adults, postprandial blood glucose control will now be increasingly targeted in the treatment of diabetes in children.

Serum motilin levels and motilin gene polymorphisms in children with functional constipation

BACKGROUND

Functional constipation is an important clinical problem among chidren all over the world. Its main cause is not completely understood. Motilin is a gastrointestinal hormone that increases intestinal motility. In this study, we aimed to investigate the serum motilin levels and its relationship with stool consistency and motilin gene polymorphisms in constipated children.

METHODS

In this study we investigated 91 constipated patients (mean age 6.84±3.55 years) and 100 healthy controls (mean age 7.78±4.25 years). Serum motilin levels were assessed by sandwich enzyme-linked immunosorbent assay. rs2281820 (c.44 C>T) and rs2281818 (c.66 C>T) mutations were evaluated for motilin gene polymorphisms.

RESULTS

Serum motilin levels were significantly lower in constipated children than healthy controls (6.20±7.86 vs. 11.54±17.89 pg/mL, respectively, P=0.008). Serum motilin levels were significantly correlated with Bristol stool scale rate (r=0.193, P=0.011) in whole study group, but in the constipation group there was no significant correlation (r=-0.072, P=0.528). There were no differences in terms of presence or distribution of the polymorphisms of rs2281820 (c.44 C>T) and rs2281818 (c.66 C>T) in both groups. There was not a significant difference between different polymorphism groups regarding serum motilin concentrations in whole study group and also in both of the study groups.

CONCLUSIONS

This study indicated for the first time that serum motilin levels decreased in constipated children. Further studies are needed to clarify whether motilin or motilin gene polymorphisms has a role in pathogenesis of functional constipation.

Electrophysiological Mechanisms of Gastrointestinal Arrhythmogenesis: Lessons from the Heart

Disruptions in the orderly activation and recovery of electrical excitation traveling through the heart and the gastrointestinal (GI) tract can lead to arrhythmogenesis. For example, cardiac arrhythmias predispose to thromboembolic events resulting in cerebrovascular accidents and myocardial infarction, and to sudden cardiac death. By contrast, arrhythmias in the GI tract are usually not life-threatening and much less well characterized. However, they have been implicated in the pathogenesis of a number of GI motility disorders, including gastroparesis, dyspepsia, irritable bowel syndrome, mesenteric ischaemia, Hirschsprung disease, slow transit constipation, all of which are associated with significant morbidity. Both cardiac and gastrointestinal arrhythmias can broadly be divided into non-reentrant and reentrant activity. The aim of this paper is to compare and contrast the mechanisms underlying arrhythmogenesis in both systems to provide insight into the pathogenesis of GI motility disorders and potential molecular targets for future therapy.

Gastric Emptying Is More Rapid in Adolescents With Type 1 Diabetes and Impacts on Postprandial Glycemia

CONTEXT

Gastric emptying is a critical determinant of postprandial glycemic control in health and type 1 diabetes. There are few studies that assess the relationship between gastric emptying and postprandial glycaemia in adolescents with type 1 diabetes.

OBJECTIVE

The objectives of the study were to quantify gastric emptying in adolescents with type 1 diabetes and examine its relationship to postprandial glycaemia and autonomic function.

DESIGN

This was a case-control study. Gastric half-emptying time of a solid meal was measured by a (13)C-octanoate breath test. Cardio-autonomic function was measured by heart rate variability. Chronic and postprandial gastrointestinal symptoms were evaluated by questionnaire and visual analog scales. Blood glucose concentrations were monitored frequently during the study.

SETTING

The study was conducted at a tertiary pediatric hospital in South Australia.

PARTICIPANTS

Thirty adolescents (aged 15 ± 2.5 y) with type 1 diabetes and age- and sex-matched controls (gastric emptying, n = 20; heart rate variability, n = 135) participated in the study.

MAIN OUTCOME

Gastric half-emptying time was the main outcome in the study.

RESULTS

Gastric emptying was more rapid in subjects with type 1 diabetes than controls [median half emptying time 78 (interquartile range 61-99) vs 109 (interquartile range 71-124) min, P = .02]. The postprandial rise in blood glucose at 60 minutes was strongly related to gastric half-emptying time (R = -0.65, P = .0001). Gastric emptying was slower in subjects with fasting hyperglycemia but was not related to heart rate variability. Nausea, bloating, and anxiety were related to fasting glycemia (P = .03).

CONCLUSION

Rapid gastric emptying is a major determinant of postprandial glycemia in adolescents with type 1 diabetes. This observation has significant implications for therapy.

Gastric emptying of solids and its relationship with microalbuminuria in children and adolescents with type 1 diabetes mellitus

BACKGROUND

The aims of the present study were to determine the frequency of delayed gastric emptying in children and adolescents with type 1 diabetes mellitus (T1DM) and to investigate the relationship between gastric emptying rate and other contributing factors (e.g. serum HbA1c, duration of diabetes and microalbuminuria) in these patients.

METHODS

This was a clinical trial evaluating the rate of gastric emptying of solid meals in 33 children and adolescents with T1DM and in 26 healthy peers using a radionuclide method. Three consecutive overnight urine collections were used to calculate the albumin excretion rate.

RESULTS

There was no significant difference in the gastric half-emptying time (GE t½ ) between patients and controls (151.7 ± 154.5 vs 109.8 ± 60.5 min, respectively; P=0.885) or the frequency of delayed gastric emptying (36.4% vs 30.8%, respectively; P=0.433). There was a moderately positive correlation between GE t½ and the duration of diabetes (r=0.380; P=0.029). There was no correlation between GE t½ and microalbumin levels in T1DM patients. In these patients, the body mass index standard deviation scores were significantly lower than in patients with normal gastric emptying (-0.13 ± 0.87 vs 0.7 ± 1.23, respectively; P=0.044).

CONCLUSION

Progression of delayed gastric emptying is more likely to be related to a longer duration of diabetes than glycemic control in children and adolescents with T1DM. Patients with delayed gastric emptying are thinner compared with patients with a normal rate of gastric emptying; they may also be asymptomatic.

Electrogastrography abnormalities appear early in children with diabetes type 1

OBJECTIVE

The objective of the study was to evaluate gastric myoelectrical activity in young patients with diabetes and to correlate it with their metabolic control [fasting blood glucose, glycosylated haemoglobin, and fructosamine] and BMI during a 3 years follow-up.

METHODS

Surface electrogastrography (EGG) was performed on 49 children with diabetes aged 10.3±4.4 (mean±SD) years and 17 age-matched healthy controls after fasting glucose, glycosylated haemoglobin, and fructosamine were measured. EGG parameters [percentage of bradygastria, 3 cycles per minute, tachygastria, dominant frequency instability coefficient, and power ratio] were analysed and compared with blood analysis.

RESULTS

Patients with diabetes exhibited an increase in preprandial bradygastria 7.9±8.8 cpm (mean±SD) compared with controls 2.1±1.0 (P=0.011), with an associated decrease in preprandial normogastria (72.2±14.5 vs. 82.7±14.7; P=0.013). Normogastric power ratio (postprandial/ preprandial power) was significantly increased in the children with diabetes compared with controls (mean: 6.67 vs. 3.14, P=0.034). A longer duration of diabetes was associated with an increased risk of EGG abnormalities (P=0.036). Marked hyperglycaemia at the time of study was associated with postprandial bradygastria (P=0.01) and power ratio bradygastria (P=0.042). Changes in glycosylated haemoglobin, fructosamine and BMI did not affect EGG parameters.

CONCLUSIONS

EGG abnormalities, presented early in a high proportion of diabetic children, are related to the acute hyperglycaemia. These abnormalities are not consistently present in the follow-up studies and not related to the glycosylated haemoglobin and fructosamine. Diabetic autonomic neuropathy is therefore an unlikely pathogenic factor for EGG abnormalities in children with diabetes.

Gastric emptying and postprandial glucose excursions in adolescents with type 1 diabetes

Because amylin is co-secreted with insulin from beta cells, patients with type 1 diabetes (T1DM) are deficient in both insulin and amylin. Amylin delays gastric emptying and suppresses glucagon in the postprandial period. Hence, we hypothesized that children with complication-naive T1DM have accelerated gastric emptying in response to a mixed meal because of amylin deficiency. Amylin, glucagon, insulin, glucose, and gastric emptying were measured in seven T1DM and in eight control subjects without diabetes. Subjects with T1DM had markedly elevated glucose concentrations when compared with controls (p < 0.0001). Amylin concentrations as predicted were lower in T1DM compared with those in controls (p < 0.0001). Insulin did not peak in the immediate postprandial period in T1DM when compared with controls (p < 0.0001). Glucagon concentrations did not significantly differ between groups. Interestingly, gastric velocity was delayed in patients with T1DM compared with controls (p < 0.01). In conclusion, subjects with T1DM do have amylin deficiency but this is not associated with accelerated gastric emptying as we had hypothesized but rather with delayed gastric emptying. Factors other than amylin play a role in control of gastric motility in T1DM. Subcutaneous insulin delivery fails to reach adequate concentrations in the postprandial period to curtail peak glucose concentration in T1DM.

Effect of tegaserod on gastric emptying and the expression of ghrelin and substance P in diabetic rats

AIM: To investigate the effect of tegaserod on gastric emptying and the expression of ghrelin and substance P (SP) in diabetic rats, and to explore the therapeutic effect of tegaserod on diabetic gastroparesis and its possible mechanism.

METHODS: Fifty Wistar rats were randomly divided into five groups: a normal control group (NC group, n = 10), a diabetes mellitus group (DM group, n = 10), a low dose tegaserod-treated group (TEG-L group, n = 10), a moderate dose tegaserod-treated group (TEG-M group, n = 10) and a high dose tegaserod-treated group (TEG-H group, n = 10). Diabetes was induced by intraperitoneal injection of streptozotocin (STZ). After 8 weeks, tegaserod was administered by intraperitoneal injection at doses of 0.1 mg/kg, 0.5 mg/kg and 1 mg/kg in TEG-L, TEG-M and TEG-H groups, respectively, for 3 days. Gastric emptying was measured by intragastric administration of phenol red. The expression of ghrelin in the gastric mucosa and SP in the gastric antrum was detected by immunohistochemistry.

RESULTS: The staining intensities for ghrelin and SP in all TEG groups were significantly decreased compared with those in the NC group (ghrelin: 34.721 ± 6.759, 33.547 ± 6.255, 35.141 ± 5.987 vs 43.514 ± 5.323, P < 0.05, P < 0.01, P < 0.01; SP: 13.548 ± 1.078, 13.952 ± 1.246, 11.845 ± 1.567 vs 16.383 ± 2.275, all P < 0.01) and increased compared with the DM group (ghrelin: 26.626 ± 4.596, all P < 0.05; SP: 9.257 ± 1.636, all P < 0.01). However, the differences in ghrelin staining intensities among TEG groups were not statistically significant. The staining intensities for SP in the TEG-L and TEG-M groups were increased compared with the TEG-H group (both P < 0.05).

CONCLUSION: Tegaserod may improve delayed gastric emptying in diabetic rats by enhancing the expression and release of ghrelin and SP.

Prevalence of EGG derangement in newly diagnosed type 1 diabetes in childhood

OBJECTIVE

To evaluate gastric myoelectrical activity in children with newly diagnosed type 1 diabetes melliltus (T1DM) in relation to blood glucose control and visceral neuropathy.

METHODS

Percutaneous electrogastrograpy (EGG) was performed on 42 children (20 F; mean age 12.9 +/- 3.1 years) with T1DM of <1 year's duration and on 35 healthy controls (18 F; mean age 13.4 +/- 3.6 years). After overnight fasting, a 30-minute EGG recording was followed by test meal consumption and then a 60-minute postprandial EGG aquisition. Fasting and postprandial periods were analyzed for gastric dysrhythmias, dominant frequency (DF) and additional parameters. In T1DM patients, HbA1c and blood glucose levels were measured and tests for visceral neuropathy were performed.

RESULTS

In 41 T1DM patients (98%), cardiovascular neuropathy tests were negative. In 12 of those patients (29%) and in 32 healthy controls (91%), electrogastrograms were normal. The percentages of fasting and postprandial gastric dysrhythmias were significantly higher in T1DM patients compared to controls (P < 0,05). In T1DM children after feeding, some normalization of gastric myoelectrical rhythm was observed: normogastria increased nearly 2-fold to 72.6 +/- 22.9% and bradygastria decreased to 20.8 +/- 20.4% from 52.3 +/- 32.4% (P < 0.05). The percentages of fasting bradygastria and normogastria were correlated with glycemia level (r = -0.55 and r = 0.51, respectively; P < 0.05), as was postprandial DF (r = 0.41; P < 0.05). There was no correlation between HbA1c levels and EGG parameters.

CONCLUSIONS

Derangement of the gastric myoelectrical activity is present in 71% of children with early stage T1DM. Glucose levels influence gastric myoelectrical activity, whereas long-term glucose control (HbA1c level) does not correlate with EGG parameters.

Early Diabetes-Related Complications in Adolescents

Micro- and macrovascular complications account for the major part of the morbidity and mortality associated with diabetes developing in childhood. Although advanced complications are exceptionally rare in the adolescent age group, it is during this phase that the progression of risk may accelerate. A number of potentially important factors have been identified which might contribute to risk of complication development: some provide insights into the genetics of these complications, while others are potentially modifiable, such as metabolic control, hypertension, smoking, obesity and hyperlipidemia. Recently, both consensus and evidence-based guidelines have been developed to guide those involved in the care of adolescents with diabetes in the prevention, screening and management of early diabetes-related complications in this vulnerable population. This article reviews the literature that underpins the available guidelines and stresses the pivotal role of excellent metabolic control in complication prevention.