The [13C]acetate breath test accurately reflects gastric emptying of liquids in both liquid and semisolid test meals

Serial change in gastric motility in eosinophilic gastritis with pyloric stenosis assessment by abdominal ultrasonography

Eosinophilic gastritis (EoG) is defined as the presence of upper gastrointestinal symptoms combined with histologic findings of > 30 eosinophils/high-power field (eos/hpf) in 5 hpf in any part of the gastric mucosa, except for the secondary causes of gastric eosinophilia. This is the first case report of a serial change in gastric motility in EoG with pyloric stenosis using abdominal ultrasonography. A 56-year-old woman was diagnosed with pyloric stenosis by upper gastrointestinal radiographic examination during a medical checkup. She had nausea and loss of appetite, her gastrointestinal symptom rating scale (GSRS) score was 20, and her F scale score was 20. Esophagogastroduodenoscopy (EGD) demonstrated pyloric stenosis and multiple superficial ulcerations in the antrum. Histopathological findings of gastric biopsy specimens revealed severe eosinophilic infiltration (100 eos/HPF), and the diagnosis was EoG with pyloric stenosis. Before treatment, the gastric anterior wall thickness was 6.3 mm. The gastric motility in EoG was evaluated by intra-abdominal ultrasonography. Ultrasonography showed low motility in the antrum, especially the amplitude and motility index. After 6 months of steroid treatment, her symptoms improved. Her GSRS score was 13, and her F scale score was 19. Histological eosinophilic infiltration decreased to 50 eos/HPF, showing improvement. On ultrasonography, gastric motility also improved and recovered to normal. After 12 months, several examinations confirmed improvement, including gastric motility by ultrasonography.

Acetate derived from the intestinal tract has a critical role in maintaining skeletal muscle mass and strength in mice

Acetate is a short-chain fatty acid (SCFA) that is produced by microbiota in the intestinal tract. It is an important nutrient for the intestinal epithelium, but also has a high plasma concentration and is used in the various tissues. Acetate is involved in endurance exercise, but its role in resistance exercise remains unclear. To investigate this, mice were administered either multiple antibiotics with and without oral acetate supplementation or fed a low-fiber diet. Antibiotic treatment for 2 weeks significantly reduced grip strength and the cross-sectional area (CSA) of muscle fiber compared with the control group. Intestinal concentrations of SCFAs were reduced in the antibiotic-treated group. Oral administration of acetate with antibiotics prevented antibiotic-induced weakness of skeletal muscle and reduced CSA of muscle fiber. Similarly, a low-fiber diet for 1 year significantly reduced the CSA of muscle fiber and fecal and plasma acetate concentrations. To investigate the role of acetate as an energy source, acetyl-CoA synthase 2 knockout mice were used. These mice had a shorter lifespan, reduced skeletal muscle mass and smaller CSA of muscle fiber than their wild type littermates. In conclusion, acetate derived from the intestinal microbiome can contribute to maintaining skeletal muscle performance.

Effects of physical form of β-lactoglobulin and calcium ingestion on GLP-1 secretion, gastric emptying and energy intake in humans: a randomised crossover trial

The aim of this study was to assess whether adding Ca2+ to aggregate or native forms of β-lactoglobulin alters gut hormone secretion, gastric emptying rates and energy intake in healthy men and women. Fifteen healthy adults (mean ± sd: 9M/6F, age: 24 ± 5 years) completed four trials in a randomised, double-blind, crossover design. Participants consumed test drinks consisting of 30 g of β-lactoglobulin in a native form with (NATIVE + MINERALS) and without (NATIVE) a Ca2+-rich mineral supplement and in an aggregated form both with (AGGREG + MINERALS) and without the mineral supplement (AGGREG). Arterialised blood was sampled for 120 min postprandially to determine gut hormone concentrations. Gastric emptying was determined using 13C-acetate and 13C-octanoate, and energy intake was assessed with an ad libitum meal at 120 min. A protein × mineral interaction effect was observed for total glucagon-like peptide-1 (GLP-1TOTAL) incremental AUC (iAUC; P < 0·01), whereby MINERALS + AGGREG increased GLP-1TOTAL iAUC to a greater extent than AGGREG (1882 ± 603 v. 1550 ± 456 pmol·l-1·120 min, P < 0·01), but MINERALS + NATIVE did not meaningfully alter the GLP-1 iAUC compared with NATIVE (1669 ± 547 v. 1844 ± 550 pmol·l-1·120 min, P = 0·09). A protein × minerals interaction effect was also observed for gastric emptying half-life (P < 0·01) whereby MINERALS + NATIVE increased gastric emptying half-life compared with NATIVE (83 ± 14 v. 71 ± 8 min, P < 0·01), whereas no meaningful differences were observed between MINERALS + AGGREG v. AGGREG (P = 0·70). These did not result in any meaningful changes in energy intake (protein × minerals interaction, P = 0·06). These data suggest that the potential for Ca2+ to stimulate GLP-1 secretion at moderate protein doses may depend on protein form. This study was registered at clinicaltrials.gov (NCT04659902).

Gastrointestinal function following endurance exercise under different environmental temperatures

PURPOSE

We determined the effects of different environmental temperatures on exercise-induced gastrointestinal (GI) damage and delayed gastric emptying (GE) rate.

METHODS

Eleven trained males completed three trials on different days, consisting of (1) exercise in a thermoneutral environment (CON, 23 °C), (2) exercise in a hot environment (HOT, 35 °C), and (3) exercise in a cold environment (COLD, 10 °C). The subjects performed high-intensity interval-type endurance exercises in all trials. Blood intestinal fatty acid binding protein (I-FABP) levels was determine before and after exercise. We evaluated Tmax (time when the 13C-excretion/h reached a maximum level) as an indication of the GE rate during post-exercise.

RESULTS

Rectal temperature during exercise was significantly higher (P < 0.001) in the HOT (38.7 ± 0.3 °C) trial compared with the CON (38.2 ± 0.3 °C) and COLD (38.2 ± 0.3 °C) trials, with no significant difference between the CON and COLD trials. Plasma I-FABP level after exercise (relative to the pre-exercise level) were significantly greater (P = 0.005) in the HOT trial (92.9 ± 69.6%) than in the CON (37.2 ± 31.6%) and COLD (37.6 ± 41.8%) trials. However, there was no significant difference between the CON and COLD trials. Moreover, the Tmax was delayed significantly (P = 0.006) in the HOT trial compared with the CON and COLD trials, with no significant difference between the CON and COLD trials.

CONCLUSION

GI function following endurance exercise was similar between thermoneutral and cold environments, while endurance exercise in a hot environment exacerbated GI function compared with thermoneutral and cold environments.

Consumption of hot protein-containing drink accelerates gastric emptying rate and is associated with higher hunger levels in older adults

Meal temperature is known to affect gastric emptying and appetite. While protein intake is recommended for older age, gastric emptying is delayed with age, resulting in loss of appetite. This study aimed to investigate whether adjusting the temperature of protein-containing drinks could improve gastric emptying and appetite in older individuals. Twenty male and female participants aged 65 years and older underwent three one-day trials in random order. Participants visited the laboratory after a 10-hour fast and consumed 200 mL of protein-containing drink dissolved in 13C-sodium acetate at 4°C, 37°C, or 60°C in a 3-minute period. Then, participants sat in a chair for 90 minutes to measure gastric emptying rate by the 13C-sodium acetate breath test and subjective appetite by a visual analog scale. The results showed that 37°C and 60°C drinks had faster gastric emptying at 5 and 10 min after ingestion than did the 4°C drink (trial-time interaction, p = 0.014). Tmax-calc, an indicator of gastric emptying rate, tended to be faster for the 37°C and 60°C drinks than for the 4°C drink (49.7 ± 17.5 min vs. 44.1 ± 18.5 min vs. 45.3 ± 25.8 min for the 4°C, 37°C, and 60°C, respectively; p = 0.085). There were no significant differences in the change in hunger from baseline among the three different temperature drinks (p > 0.05). Only in the 60°C trial, a shorter gastric emptying time was associated with greater hunger (r=-0.554, p = 0.021). These findings suggest that hot protein-containing drinks may accelerate gastric emptying and contribute to rapid nutrient intake and increased appetite in older adults.

Imaging in Gastroparesis: Exploring Innovative Diagnostic Approaches, Symptoms, and Treatment

Gastroparesis (GP) is a chronic disease characterized by upper gastrointestinal symptoms, primarily nausea and vomiting, and delayed gastric emptying (GE), in the absence of mechanical GI obstruction. The underlying pathophysiology of GP remains unclear, but factors contributing to the condition include vagal nerve dysfunction, impaired gastric fundic accommodation, antral hypomotility, gastric dysrhythmias, and pyloric dysfunction. Currently, gastric emptying scintigraphy (GES) is considered the gold standard for GP diagnosis. However, the overall delay in GE weakly correlates with GP symptoms and their severity. Recent research efforts have focused on developing treatments that address the presumed underlying pathophysiological mechanisms of GP, such as pyloric hypertonicity, with Gastric Peroral Endoscopic Myotomy (G-POEM) one of these procedures. New promising diagnostic tools for gastroparesis include wireless motility capsule (WMC), the 13 carbon-GE breath test, high-resolution electrogastrography, and the Endoluminal Functional Lumen Imaging Probe (EndoFLIP). Some of these tools assess alterations beyond GE, such as muscular electrical activity and pyloric tone. These modalities have the potential to characterize the pathophysiology of gastroparesis, identifying patients who may benefit from targeted therapies. The aim of this review is to provide an overview of the current knowledge on diagnostic pathways in GP, with a focus on the association between diagnosis, symptoms, and treatment.

Effects of co-ingesting glucose and whey protein on blood glucose, plasma insulin and glucagon concentrations, and gastric emptying, in older men with and without type 2 diabetes

AIM

To investigate whether co-ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycaemia in older men with type 2 diabetes (T2D).

MATERIALS AND METHODS

Blood glucose, plasma insulin and glucagon concentrations were measured for 180 minutes following ingestion of a drink containing 30 g of glucose (G; 120 kcal), 30 g of whey protein (120 kcal), 30 g of glucose plus 30 g of whey protein (GP; 240 kcal), or control (~2 kcal) in older men with T2D (n = 10, 77 ± 1 years; 31 ± 1.7 kg/m² ) and without T2D (n = 10, 78 ± 2 years; 27 ± 1.4 kg/m² ). Mixed model analysis was used.

RESULTS

GP versus G markedly reduced the increase in blood glucose concentrations (P < .001) and had a synergistic effect on the increase in insulin concentrations (P < .001), in men both with and without T2D. Glucose concentrations were higher in men with T2D compared with those without T2D, whereas insulin and glucagon concentrations were largely unaffected by the presence of T2D. Gastric emptying was faster in men with T2D than in those without T2D.

CONCLUSIONS

The ability of whey protein to reduce carbohydrate-induced, postprandial hyperglycaemia is retained in older men with T2D compared with those without T2D, and whey protein supplementation may be a useful strategy in the prevention and management of T2D in older people.

Delayed Gastric Emptying and Gastric Remnant Function After Pancreaticoduodenectomy: A Systematic Review of Objective Assessment Modalities

BACKGROUND

Delayed gastric emptying (DGE) is a frequent complication after pancreaticoduodenectomy (PD). The diagnosis of DGE is based on International Study Group for Pancreatic Surgery (ISGPS) clinical criteria and objective assessments of DGE are infrequently used. The present literature review aimed to identify objective measures of DGE following PD and determine whether these measures correlate with the clinical definition of DGE.

METHODS

A systematic search was performed using the MEDLINE Ovid, EMBASE, Google Scholar and CINAHL databases for studies including pancreatic surgery, delayed gastric emptying and gastric motility until June 2022. The primary outcome was modalities undertaken for the objective measurement of DGE following PD and correlation between objective measurements and clinical diagnosis of DGE. Relevant risk of bias analysis was performed.

RESULTS

The search revealed 4881 records, of which 46 studies were included in the final analysis. There were four objective modalities of DGE assessment including gastric scintigraphy (n = 28), acetaminophen/paracetamol absorption test (n = 10), fluoroscopy (n = 6) and the ¹³C-acetate breath test (n = 3). Protocols were inconsistent, and reported correlations between clinical and objective measures of DGE were variable; however, amongst these measures, at least one study directly or indirectly inferred a correlation, with the greatest evidence accumulated for gastric scintigraphy.

CONCLUSION

Several objective modalities to assess DGE following PD have been identified and evaluated, however are infrequently used. Substantial variability exists in the literature regarding indications and interpretation of these tests, and there is a need for a real-time objective modality which correlates with ISGPS DGE definition after PD.

The Impact of Heat Acclimation on Gastrointestinal Function following Endurance Exercise in a Hot Environment

To determine the effects of heat acclimation on gastrointestinal (GI) damage and the gastric emptying (GE) rate following endurance exercise in a hot environment. Fifteen healthy men were divided into two groups: endurance training in hot (HOT, 35 °C, n = 8) or cool (COOL, 18 °C, n = 7) environment. All subjects completed 10 days of endurance training (eight sessions of 60 min continuous exercise at 50% of the maximal oxygen uptake (V·O2max). Subjects completed a heat stress exercise tests (HST, 60 min exercise at 60% V·O2max) to evaluate the plasma intestinal fatty acid-binding protein (I-FABP) level and the GE rate following endurance exercise in a hot environment (35 °C) before (pre-HST) and after (post-HST) the training period. We assessed the GE rate using the ¹³C-sodium acetate breath test. The core temperature during post-HST exercise decreased significantly in the HOT group compared to the pre-HST (p = 0.004) but not in the COOL group. Both the HOT and COOL groups showed exercise-induced plasma I-FABP elevations in the pre-HST (p = 0.002). Both groups had significantly attenuated exercise-induced I-FABP elevation in the post-HST. However, the reduction of exercise-induced I-FABP elevation was not different significantly between both groups. GE rate following HST did not change between pre- and post-HST in both groups, with no significant difference between two groups in the post-HST. Ten days of endurance training in a hot environment improved thermoregulation, whereas exercise-induced GI damage and delay of GE rate were not further attenuated compared with training in a cool environment.

Effects of soy protein isolate and soy peptide preload on gastric emptying rate and postprandial glycemic control in healthy humans

Background

This study aims to compare the effects of soy protein isolate (SPI) and soy peptide (PEP) preload 30 min before a 75-g oral glucose tolerance test (OGTT) on the gastric emptying rate, plasma insulin, and blood glucose responses.

Methods

Nine healthy young subjects were evaluated on four occasions. The participants consumed a 200-ml solution containing either 20 g of SPI or PEP in experiment 1. In experiment 2, 30 min after consuming either 20 g of SPI or PEP solutions, an OGTT was performed to evaluate the individual glycemic response. The gastric emptying rate was measured by the ¹³C-sodium acetate breath test. Blood glucose and plasma insulin were measured before and after consuming either the SPI or PEP solutions and during the OGTT.

Results

In experiment 1, plasma insulin levels were higher 30 min after consuming the PEP solution than after the SPI solution. PEP resulted in a faster gastric emptying rate than SPI. In experiment 2, just before performing the OGTT, the plasma insulin response was higher for PEP than for SPI. Fifteen minutes after starting the OGTT, the blood glucose response was lower after consuming PEP than after SPI. The gastric emptying rate tended to be faster after consuming PEP than after SPI (p = 0.08).

Conclusion

A PEP preload might be slightly more effective for the suppression of postprandial blood glucose excursion compared with SPI; thus, a PEP preload potentially induces an enhanced insulin response just before the OGTT.

Clinical and Molecular Insights into Gastrointestinal Dysfunction in Myotonic Dystrophy Types 1 & 2

Myotonic dystrophy (DM) is a highly variable, multisystemic disorder that clinically affects one in 8000 individuals. While research has predominantly focused on the symptoms and pathological mechanisms affecting striated muscle and brain, DM patient surveys have identified a high prevalence for gastrointestinal (GI) symptoms amongst affected individuals. Clinical studies have identified chronic and progressive dysfunction of the esophagus, stomach, liver and gallbladder, small and large intestine, and rectum and anal sphincters. Despite the high incidence of GI dysmotility in DM, little is known regarding the pathological mechanisms leading to GI dysfunction. In this review, we summarize results from clinical and molecular analyses of GI dysfunction in both genetic forms of DM, DM type 1 (DM1) and DM type 2 (DM2). Based on current knowledge of DM primary pathological mechanisms in other affected tissues and GI tissue studies, we suggest that misregulation of alternative splicing in smooth muscle resulting from the dysregulation of RNA binding proteins muscleblind-like and CUGBP-elav-like is likely to contribute to GI dysfunction in DM. We propose that a combinatorial approach using clinical and molecular analysis of DM GI tissues and model organisms that recapitulate DM GI manifestations will provide important insight into defects impacting DM GI motility.

Measurement of Gastric Emptying Using a 13C-octanoic Acid Breath Test with Wagner-Nelson Analysis and Scintigraphy in Type 2 Diabetes

INTRODUCTION

Breath tests utilising ¹³C-labelled substrates for the assessment of gastric emptying have been applied widely. Wagner-Nelson analysis is a pharmacokinetic model that can be utilised to generate a gastric emptying curve from the % ¹³CO₂ measured in breath samples. We compared Wagner-Nelson analysis with (i) scintigraphy and (ii) conventional breath test modelling to quantify gastric emptying in type 2 diabetes.

METHODS

Thirteen patients (age 68.1±1.5 years, body mass index 31.0±0.9 kg/m², HbA1c 6.3±0.2%) consumed a mashed potato meal comprising 65 g powdered potato, 20 g glucose, 250 ml water, an egg yolk labelled with 100 μL ¹³C-octanoic acid and 20MBq ^99mTc-calcium phytate. Scintigraphic data were acquired and breath samples collected for 4 hours after the meal. Gastric emptying curves were derived based on each technique; the 50% emptying time and intragastric retention at 60 min were also calculated.

RESULTS

With Wagner-Nelson analysis, a K_el=0.60 (the elimination constant) best approximated the scintigraphic gastric emptying curve. There was a relationship between the T50 calculated with scintigraphy and by both Wagner-Nelson K_el=0.60 (r²=0.45, P<0.05) and conventional analysis (r²=0.44, P<0.05). There was no significant difference in the 50% gastric emptying time for scintigraphy (68.5±4.8 min) and Wagner-Nelson K_el=0.60 (71.3±4.5 min), however, the 50% gastric emptying time calculated by conventional analysis was much greater at 164.7±6.0 min (P<0.001).

CONCLUSION

In type 2 diabetes, gastric emptying of a mashed potato meal measured using a ¹³C-octanoic acid breath test analysed with Wagner-Nelson K_el=0.60 closely reflects measurements obtained with scintigraphy, whereas, in absolute terms, the conventional breath test analysis does not.

Effects of different temperatures of carbohydrate-protein-containing drinks on gastric emptying rate after exercise in healthy young men: randomized crossover trial

Background

The present study examined the effects of different temperatures of carbohydrate-protein-containing drinks after exercise on the subsequent gastric emptying rate in healthy young men.

Methods

Twelve healthy young men completed two, 1-day trials in random order. In both trials, the participants completed intermittent cycling exercise for 20 min, consisting of a 120% heart rate peak for 20 s, followed by 25 W for 40 s. Participants consumed 400 mL of carbohydrate-protein-containing drink (0.85 MJ) at 4 °C (EX + 4 °C) or 60 °C (EX + 60 °C) over a 5-min period after exercise. The participants sat on a chair for 2.5 h to measure their gastric emptying rate using the ¹³C-sodium acetate breath test. Subjective feelings of gastrointestinal discomfort and appetite were measured using a visual analog scale. Interstitial fluid glucose levels after drinking were measured using a continuous glucose-monitoring device.

Results

The percentage excretion of ¹³CO₂ tended to be higher at EX + 60 °C than at EX + 4 °C from the start of the test until 30 min after drink ingestion (5.7 ± 0.5 vs. 6.5 ± 0.4%dose/h for the EX + 4 °C and EX + 60 °C trials, respectively; effect sizes [ES] = 0.277, p = 0.065). The time of maximum ¹³CO₂ emissions per hour (Tmax-calc) and the time of half ¹³CO₂ emissions per hour (T_1/2) did not differ between trials. Subjective gastrointestinal discomfort was lower at EX + 60 °C compared to EX + 4 °C (ES = 0.328, p = 0.041). There were no significant differences in interstitial fluid glucose levels between the different temperatures of carbohydrate-protein-containing drinks after exercise (p = 0.698).

Conclusions

Consumption of warm carbohydrate-protein-containing drinks after exercise may accelerate gastric emptying in the very early phase and may reduce gastric discomfort.

Trial registration

University Hospital Medical Information Network, UMIN000045626. Registered on June 10, 2021.

Dietary Fibre and Organic Acids in Kiwifruit Suppress Glycaemic Response Equally by Delaying Absorption-A Randomised Crossover Human Trial with Parallel Analysis of 13C-Acetate Uptake

Non-sugar components of kiwifruit reduce the amplitude of the glycaemic response to co-consumed cereal starch. We determined the relative contribution of different non-sugar kiwifruit components to this anti-glycaemic effect. Healthy participants (n = 9) ingested equal carbohydrate meals containing 20 g starch as wheat biscuit (WB, 30 g), and the sugar equivalent of two kiwifruit (KFsug, 20.4 g), either intrinsic or added as glucose, fructose and sucrose (2:2:1). The meals were WB+KFsug (control, no non-sugar kiwifruit components), WB + whole kiwifruit pulp (WB+KF), WB + neutralised kiwifruit pulp (WB+KFneut), WB + low-fibre kiwifruit juice (WB+KFjuice) and WB+KFsug + kiwifruit organic acids (WB+KFsug+OA). All meals were spiked with 100 mg sodium [1-13C] acetate to measure intestinal absorption. Each participant ingested all meals in random order. Blood glucose and breath 13CO2 were measured at ingestion and at 15 min intervals up to 180 min. Compared with WB+KFsug, whole kiwifruit pulp (WB+KF) almost halved glycaemic response amplitude (p < 0.001), reduced incremental area under the blood glucose response curve (iAUC) at 30 min (peak) by 50% (p < 0.001), and averted late postprandial hypoglycaemia. All other treatments suppressed response amplitude half as much as whole kiwifruit and averted acute hypoglycaemia, with little effect on iAUC. Effects on 13CO2 exhalation paralleled effects on blood glucose (R2 = 0.97). Dietary fibre and organic acids contributed equally to the anti-glycaemic effect of kiwifruit by reducing intestinal absorption rate. Kiwifruit flesh effectively attenuates glycaemic response in carbohydrate exchange, as it contains fructose, dietary fibre and organic acids.

Comparative Effects of Co-Ingesting Whey Protein and Glucose Alone and Combined on Blood Glucose, Plasma Insulin and Glucagon Concentrations in Younger and Older Men

The ingestion of dietary protein with, or before, carbohydrate may be a useful strategy to reduce postprandial hyperglycemia, but its effect in older people, who have an increased predisposition for type 2 diabetes, has not been clarified. Blood glucose, plasma insulin and glucagon concentrations were measured for 180 min following a drink containing either glucose (120 kcal), whey-protein (120 kcal), whey-protein plus glucose (240 kcal) or control (~2 kcal) in healthy younger (n = 10, 29 ± 2 years; 26.1 ± 0.4 kg/m2) and older men (n = 10, 78 ± 2 years; 27.3 ± 1.4 kg/m2). Mixed model analysis was used. In both age groups the co-ingestion of protein with glucose (i) markedly reduced the increase in blood glucose concentrations following glucose ingestion alone (p < 0.001) and (ii) had a synergistic effect on the increase in insulin concentrations (p = 0.002). Peak insulin concentrations after protein were unaffected by ageing, whereas insulin levels after glucose were lower in older than younger men (p < 0.05) and peak insulin concentrations were higher after glucose than protein in younger (p < 0.001) but not older men. Glucagon concentrations were unaffected by age. We conclude that the ability of whey-protein to reduce carbohydrate-induced postprandial hyperglycemia is retained in older men and that protein supplementation may be a useful strategy in the prevention and management of type 2 diabetes in older people.

The [13 C]octanoic acid breath test for gastric emptying quantification: A focus on nutrition and modeling

Gastric emptying (GE) is the process of food being processed by the stomach and delivered to the small intestine where nutrients such as lipids are absorbed into the blood circulation. The combination of an easy and inexpensive method to measure GE such as the CO₂ breath test using the stable isotope [¹³C]octanoic acid with semi‐mechanistic modeling could foster a wider application in nutritional studies to further understand the metabolic response to food. Here, we discuss the use of the [¹³C]octanoic acid breath test to label the solid phase of a meal, and the factors that influence GE to support mechanistic studies. Furthermore, we give an overview of existing mathematical models for the interpretation of the breath test data and how much nutritional studies could benefit from a physiological based pharmacokinetic model approach.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Supraphysiological effects of pancreatic polypeptide on gastric motor function and nutrient tolerance in humans

Pancreatic polypeptide (PP) is known to affect food intake. In this exploratory study, we set out to investigate its supraphysiological effect on food tolerance, gastric accommodation, and emptying. In 12 healthy volunteers, 0, 3, or 10 pmol*kg-1 *min-1 PP was administered intravenously (PP0, PP3 or PP10). Thirty minutes thereafter, nutrient drink infusion (60 ml*min-1 ) through a nasogastric feeding tube was started until maximum satiation. Gastric accommodation was assessed by measuring the intragastric pressure (IGP; nasogastric manometry). In a separate test, the effect of PP0 or PP10 on gastric emptying was tested in 10 healthy volunteers and assessed using the 13 C breath test. Results are presented as mean ± SEM, and p < 0.05 was considered significant. For the IGP test, PP increased ingested nutrient volume: 886 ± 93, 1059 ± 124, and 1025 ± 125 ml for PP0, PP3, and PP10, respectively (p = 0.048). In all groups, Nadir IGP values were reached upon food intake (transformed values: 1.5 ± 0.2, 1.7 ± 0.3, and 1.6 ± 0.3 mmHg for PP0, PP3, and PP10, respectively; NS) to return to baseline thereafter. For the gastric emptying study, volunteers ingested a similar nutrient volume: 802 ± 119 and 1089 ± 128 ml (p = 0.016), and gastric half-emptying time was 281 ± 52 and 249 ± 37 min for PP0 and PP10, respectively (NS). No significant correlation between tolerated nutrient volume and IGP drop (R² < 0.01; p = 0.88 for PP0 vs. PP3 and R² =0.07; p = 0.40 for PP0 vs. PP10, respectively) or gastric half-emptying time (R² = 0.12; p = 0.32) was found. A supraphysiological PP dose enhances food tolerance; however, this effect is not mediated through gastric motility. CLINICAL TRIAL REGISTRY NUMBER: NCT03854708 is obtained from clinicaltrials.gov.

European guideline on indications, performance and clinical impact of 13 C-breath tests in adult and pediatric patients: An EAGEN, ESNM, and ESPGHAN consensus, supported by EPC

Introduction

¹³C‐breath tests are valuable, noninvasive diagnostic tests that can be widely applied for the assessment of gastroenterological symptoms and diseases. Currently, the potential of these tests is compromised by a lack of standardization regarding performance and interpretation among expert centers.

Methods

This consensus‐based clinical practice guideline defines the clinical indications, performance, and interpretation of ¹³C‐breath tests in adult and pediatric patients. A balance between scientific evidence and clinical experience was achieved by a Delphi consensus that involved 43 experts from 18 European countries. Consensus on individual statements and recommendations was established if ≥ 80% of reviewers agreed and <10% disagreed.

Results

The guideline gives an overview over general methodology of ¹³C‐breath testing and provides recommendations for the use of ¹³C‐breath tests to diagnose Helicobacter pylori infection, measure gastric emptying time, and monitor pancreatic exocrine and liver function in adult and pediatric patients. Other potential applications of ¹³C‐breath testing are summarized briefly. The recommendations specifically detail when and how individual ¹³C‐breath tests should be performed including examples for well‐established test protocols, patient preparation, and reporting of test results.

Conclusion

This clinical practice guideline should improve pan‐European harmonization of diagnostic approaches to symptoms and disorders, which are very common in specialist and primary care gastroenterology practice, both in adult and pediatric patients. In addition, this guideline identifies areas of future clinical research involving the use of ¹³C‐breath tests.

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.

The Effect of Continuous Intake of Lactobacillus gasseri OLL2716 on Mild to Moderate Delayed Gastric Emptying: A Randomized Controlled Study

Probiotics have been suggested to be effective for functional dyspepsia, but their effect on gastric motility is not clear. We evaluated the effect of Lactobacillus gasseri OLL2716 (LG21 strain) on mild to moderate delayed gastric emptying by a double-blind, parallel-group, placebo-controlled, randomized trial. Participants (n = 28) were randomly assigned to ingest LG21 strain-containing yogurt (LG21 strain group) or LG21 strain-free yogurt (placebo group) for 12 weeks. The ¹³C gastric emptying breath test was performed to measure the gastric emptying rate over time following ingestion of a liquid meal, and the time to reach the peak (Tmax) was used as an indicator of gastric emptying. We also measured the salivary amylase concentration, an indicator of autonomic dysfunction under stress. The per-protocol population (n = 27, male n = 4, female n = 23) was evaluated for efficacy. When a ≥30% reduction in the difference between participant's Tmax and the Japanese mean Tmax was defined as an improvement, the odds ratio of improvement in delayed gastric emptying compared to placebo after 12 weeks was 4.1 (95% confidence interval, 0.8 to 20.2). Moreover, salivary amylase concentrations were significantly lower than in the placebo group, indicating an improvement in autonomic function. The present data were not enough to support the beneficial effects of the LG21 strain on delayed gastric emptying. However, if we define the odds ratio in further study investigated with a larger number of participants, LG21 strain might be expected to have some impact on delayed gastric emptying.

The validity and reliability of a novel isotope ratio infrared spectrometer to quantify 13C enrichment of expired breath samples in exercise

The traditional method to measure ¹³CO₂ enrichment in breath involves isotope ratio mass spectrometry (IRMS), which has several limitations such as cost, extensive training, and large space requirements. Here, we present the validity and reliability data of an isotope ratio infrared spectrometer (IRIS)-based method developed to combat these limitations. Eight healthy male runners performed 105 min of continuous running on a motorized treadmill while ingesting various carbohydrate beverages enriched with ¹³C and expired breath samples were obtained every 15 min in triplicates. A total of 213 breath samples were analyzed using both methods, whereas 212 samples were repeated using IRIS to determine test-retest reliability. Bland-Altman analysis was performed to determine systematic and proportional bias, and intraclass correlation coefficient (ICC) and coefficient of variation (CV) to assess level of agreement and magnitude of error. The IRIS method demonstrated a small but significant systematic bias to overestimate δ¹³CO₂ (0.18‰; P < 0.05) compared with IRMS, without any proportional bias or heteroscedasticity and a small CV (0.5%). There was a small systematic bias during the test-retest of the IRIS method (-0.07‰; P < 0.05), no proportional bias, an excellent ICC (1.00), and small CV (0.4%). The use of the Delta Ray IRIS to determine ¹³C enrichment in expired breath samples captured during exercise has excellent validity and reliability when compared with the gold standard IRMS.NEW & NOTEWORTHY The use of IRIS to determine ¹³C enrichment in expired breath samples captured during exercise to determine exogenous glucose oxidation during exercise has excellent validity and reliability when compared with the gold standard IRMS.

Heated Corn Oil and 2,4-Decadienal Suppress Gastric Emptying and Energy Intake in Humans

Consumption of 2,4-decadienal (2,4-DD) delays gastric emptying (GE) rate in animals. Oil heating produces 2,4-DD and other aldehydes. Here we examined whether heated oil affects GE rate and food intake in humans, and whether it is mediated by 2,4-DD. In the first experiment, 10 healthy volunteers consumed 240-g pumpkin soup with 9.2 g of heated (HO) or non-heated corn oil (CO). Subsequently, 17 participants consumed pumpkin soup containing 3.1 g of either heated corn oil (HO), 1 mg 2,4-DD + non-heated corn oil (2,4-DD), or non-heated corn oil (CO). Sixty minutes following pumpkin soup, cod roe spaghetti was provided, and then energy intake was determined. To evaluate GE rate, ¹³C breath test (Experiment 1) and ultrasonography (Experiments 1 and 2) were used. The results from the Experiment 1 confirmed that consumption of heated corn oil reduced GE rate. Experiment 2 showed a delayed GE rate in HO and 2,4-DD trials compared with CO trial (p < 0.05). Energy intake was approximately 600–650 kJ lower in HO and 2,4-DD trials compared with CO trial (p < 0.05). These findings suggest that 2,4-DD, either formed by oil heating or added to food, contributes to suppressing GE rate and energy intake.

Body surface mapping of the stomach: New directions for clinically evaluating gastric electrical activity

BACKGROUND

Gastric motility disorders, which include both functional and organic etiologies, are highly prevalent. However, there remains a critical lack of objective biomarkers to guide efficient diagnostics and personalized therapies. Bioelectrical activity plays a fundamental role in coordinating gastric function and has been investigated as a contributing mechanism to gastric dysmotility and sensory dysfunction for a century. However, conventional electrogastrography (EGG) has not achieved common clinical adoption due to its perceived limited diagnostic capability and inability to impact clinical care. The last decade has seen the emergence of novel high-resolution methods for invasively mapping human gastric electrical activity in health and disease, providing important new insights into gastric physiology. The limitations of EGG have also now become clearer, including the finding that slow-wave frequency alone is not a reliable discriminator of gastric dysrhythmia, shifting focus instead toward altered spatial patterns. Recently, advances in bioinstrumentation, signal processing, and computational modeling have aligned to allow non-invasive body surface mapping of the stomach to detect spatiotemporal gastric dysrhythmias. The clinical relevance of this emerging strategy to improve diagnostics now awaits determination.

PURPOSE

This review evaluates these recent advances in clinical gastric electrophysiology, together with promising emerging data suggesting that novel gastric electrical signatures recorded at the body surface (termed "body surface mapping") may correlate with symptoms. Further technological progress and validation data are now awaited to determine whether these advances will deliver on the promise of clinical gastric electrophysiology diagnostics.

Electrogastrographic and autonomic nervous system responses to solid and liquid meals in youth with functional dyspepsia

BACKGROUND

Meal-related symptoms are common in paediatric functional dyspepsia (FD). There are only a small number of paediatric studies assessing mechanisms for meal-related symptoms, and these have not utilized Rome IV criteria. The aim of the current study was to assess gastric myoelectric and autonomic nervous system (ANS) responses to both liquid and solid meals in youth with Rome IV-defined FD.

METHODS

In healthy controls (N = 14) and youth with FD (N = 12), we recorded electrocardiograph (to assess heart rate variability; HRV) and electrogastrograph (EGG) signals before and after two test meals, one liquid and one solid. EGG parameters and HRV were assessed for the entire pre- and postprandial periods and in short time intervals. Additionally, liquid gastric emptying was assessed utilizing a ¹³ C-acetate breath test.

KEY RESULTS

During the EGG, the dominant power increased with both meals in controls but not patients with FD. During HRV assessment, the low frequency to high frequency ratio was higher after the liquid meal in controls, despite being similar preprandial, as compared to patients with FD. In controls, both standard deviation of normal to normal waves (SDNN) and root mean square of successive ECG R peaks (R-R interval) differences (rMSSD) increased after the liquid meal (but not after the solid meal) in controls but not patients with FD.

CONCLUSIONS AND INFERENCES

Youth with Rome IV-defined FD lacks the normal postprandial EGG dominant power response or autonomic nervous system response following a liquid meal. The latter appears to indicate a lack of ANS flexibility.

Wheat Protein Hydrolysate Fortified With l-Arginine Enhances Satiation Induced by the Capsaicinoid Nonivamide in Moderately Overweight Male Subjects

SCOPE

Increasing the intake of satiety-enhancing food compounds represents a promising strategy for maintaining a healthy body weight. Recently, satiating effects for the capsaicinoid nonivamide have been demonstrated. As various proteins and amino acids have also been demonstrated to decrease energy intake, oral glucose tolerance test (oGTT)-based bolus interventions of 75 g glucose + 0.15 mg nonivamide (NV control) are tested with/without combination of a wheat protein hydrolysate (WPH: 2 g) and/or l-arginine (ARG: 3.2 g) for their satiating effects in 27 moderately overweight male subjects.

METHODS AND RESULTS

Compared to NV control intervention, ARG and WPH + ARG treatment both reduce (p < 0.01) total calorie intake from a standardized breakfast by -5.9 ± 4.15% and -6.07 ± 4.38%, respectively. For the WPH + ARG intervention, increased mean plasma serotonin concentrations (AUC: 350 ± 218), quantitated by ELISA, and delayed gastric emptying, assessed by 13 C-Na-acetate breath test (-2.10 ± 0.51%, p < 0.05), are demonstrated compared to NV control. Correlation analysis between plasma serotonin and gastric emptying reveals a significant association after WPH ± ARG intervention (r = -0.396, p = 0.045).

CONCLUSION

Combination of WPH and ARG enhances the satiating effect of nonivamide, providing opportunities to optimize satiating food formulations by low amounts of the individual food constituents.

Coexistence of Alterations of Gastrointestinal Function and Mechanical Allodynia in the Reserpine-Induced Animal Model of Fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a disorder characterized by widespread chronic pain as core symptom and a broad range of comorbidities. Despite the prevalence of gastrointestinal (GI) comorbidities in patients with FM, GI functions have rarely been investigated in animal models of FM.

AIMS

The purpose of the present study is to investigate the coexistence of alterations of GI function in the reserpine-induced myalgia (RIM) rat, a validated FM model associated with disruption of monoamine system.

METHODS

Paw withdrawal threshold (von Frey hair test) was assessed as pain-associated indicator. Gastric emptying (¹³C breath test), small intestinal transit (charcoal meal test), and fecal water content were investigated as GI functions.

RESULTS

The specific regimen of reserpine for the RIM rat, i.e., 1 mg/kg s.c., once daily for three consecutive days, caused a reduction of paw withdrawal threshold (i.e., mechanical allodynia) on days 3, 5, and 7 after the first injection. The ¹³CO₂ excreted from the RIM rat was significantly increased on day 7. The RIM rat exhibited an acceleration of small intestinal transit on day 5. Fecal water content collected from the RIM rat was significantly increased on days 3 and 5. The amount of noradrenaline was significantly decreased in GI tissues on days 3, 5, and 7 in the RIM rat. Conclusions This study revealed that accelerated gastric emptying, accelerated small intestinal transit, and increase in fecal water content coexist with mechanical allodynia in the RIM rat, simulating the coexistence of chronic pain and alterations of GI function in patients with FM.

Suppression of sweet sensing with glucose, but not aspartame, delays gastric emptying and glycemic response

Previously, we reported that oral stimulation with Gymnema sylvestre (GS), a plant that selectively suppresses sweet taste sensation in humans, delayed gastric emptying and glycemic response during and after oral glucose ingestion. It is unclear whether these responses are triggered by sweet taste sensing per se. We tested the hypothesis that the effects of sweet taste sensing involving a low-energy sweetener, aspartame, alters gastric emptying, blood glucose, and plasma insulin responses during and after the prandial phase. Nine participants rinsed their mouths with either 25 mL of water (control) or a 2.5% GS solution, and then ingested 200 g (50 g × four times) of either 0.09% aspartame or 15% glucose solution containing 100 mg of ¹³C-sodium acetate. Gastric emptying was measured with a ¹³C breath test. Blood glucose and plasma insulin were measured at baseline as well as during and after ingestion of the sweet solutions. Decreased subjective sweet taste intensity was observed in the GS group for both the aspartame and glucose trials. In the aspartame trial, no measurements showed significant differences between either group. In the glucose trial, gastric emptying was delayed in the GS group compared to controls. In the initial phase, both during and after glucose ingestion in the glucose trial, blood glucose and plasma insulin responses were lower in the GS group than the controls. The presence or absence of sweet taste-sensing involving glucose had a significant effect on gastric emptying and glycemic metabolism, both during and after the prandial phase, as opposed to the effects involving aspartame.

Duodenal Chemosensing of Short-Chain Fatty Acids: Implications for GI Diseases

PURPOSE OF REVIEW

Short-chain fatty acids (SCFAs), the main bacterial fermentation products in the hindgut of hindgut fermenters, are also present in the foregut lumen. We discuss the impact of SCFAs in the duodenal defense mechanisms and in the gastrointestinal (GI) pathogenesis.

RECENT FINDINGS

Luminal SCFAs augment the duodenal mucosal defenses via release of serotonin (5-HT) and glucagon-like peptide-2 (GLP-2) from enteroendocrine cells. Released GLP-2 protects the small intestinal mucosa from nonsteroidal anti-inflammatory drug-induced enteropathy. SCFAs are also rapidly absorbed via SCFA transporters and interact with afferent and myenteric nerves. Excessive SCFA signals with 5-HT₃ receptor overactivation may be implicated in the pathogenesis of irritable bowel syndrome symptoms. SCFA production exhibits diurnal rhythms with host physiological responses, suggesting that oral SCFA treatment may adjust the GI clocks. SCFAs are not only a source of energy but also signaling molecules for the local regulation of the GI tract and systemic regulation via release of gut hormones. Targeting SCFA signals may be a novel therapeutic for GI diseases and metabolic syndrome.

Time-Restricted Feeding Improves Glucose Tolerance in Men at Risk for Type 2 Diabetes: A Randomized Crossover Trial

OBJECTIVE

This study aimed to assess the effects of 9-hour time-restricted feeding (TRF), early (TRFe) or delayed (TRFd), on glucose tolerance in men at risk for type 2 diabetes.

METHODS

Fifteen men (age 55 ± 3 years, BMI 33.9 ± 0.8 kg/m² ) wore a continuous glucose monitor for 7 days of baseline assessment and during two 7-day TRF conditions. Participants were randomized to TRFe (8 am to 5 pm) or TRFd (12 pm to 9 pm), separated by a 2-week washout phase. Glucose, insulin, triglycerides, nonesterified fatty acids, and gastrointestinal hormone incremental areas under the curve were calculated following a standard meal on days 0 and 7 at 8 am (TRFe) or 12 pm (TRFd).

RESULTS

TRF improved glucose tolerance as assessed by a reduction in glucose incremental area under the curve (P = 0.001) and fasting triglycerides (P = 0.003) on day 7 versus day 0. However, there were no mealtime by TRF interactions in any of the variables examined. There was also no effect of TRF on fasting and postprandial insulin, nonesterified fatty acids, or gastrointestinal hormones. Mean fasting glucose by continuous glucose monitor was lower in TRFe (P = 0.02) but not TRFd (P = 0.17) versus baseline, but there was no difference between TRF conditions.

CONCLUSIONS

While only TRFe lowered mean fasting glucose, TRF improved glycemic responses to a test meal in men at risk for type 2 diabetes regardless of the clock time that TRF was initiated.

Gastric Emptying of Elemental Liquid Diets Versus Semisolid Diets in Bedridden Gastrostomy-fed Patients

BACKGROUND

Aspiration is a common problem in bedridden gastrostomy-fed patients. We compared gastric emptying of an elemental liquid diet and a commercial semisolid diet in bedridden gastrostomy-fed patients.

METHODS

Study 1: from January 2013 to December 2016, consecutive bedridden patients receiving percutaneous endoscopic gastrostomy (PEG) semisolid feeding hospitalized due to aspiration pneumonia were switched to elemental liquid diet feedings. The frequency of defecation, tube feed contents aspirated from the trachea, and aspiration pneumonia during hospitalization were retrospectively reviewed. Study 2 was a randomized, crossover trial comparing C sodium acetate gastric emptying of a commercial elemental liquid or a commercial semisolid diet in bedridden PEG patients and controls.

RESULTS

Study 1: 18 patients were enrolled. Elemental liquid diet was aspirated from the trachea in 1 (5.6%) (once in 24 observations); neither aspiration pneumonia nor diarrhea developed during elemental liquid diet feeding over 2 weeks observation. Study 2: 8 PEG patients and 8 healthy subjects were separately randomized to assess gastric emptying of the commercial elemental and semisolid diets. The elemental liquid diet was associated with a significant decrease of the 10%, 30%, or 50% emptying (excretion) time (P<0.05) and an increased the area under the curve (% dose/h) compared with the commercial semisolid diet (P<0.05). In healthy subjects there was no significant difference in gastric empting between the 2 diets.

CONCLUSIONS

Elemental liquid diets emptied more rapidly from the stomach than semisolid diets in bedridden PEG patients. They may prevent or reduce aspiration pneumonia compared with semisolid diets.

The Effect of Glucose or Fructose Added to a Semi-solid Meal on Gastric Emptying Rate, Appetite, and Blood Biochemistry

The ingestion of fructose is of interest due to previously reported differences in gastrointestinal, appetite, and metabolic effects when compared to glucose ingestion when ingested in liquid solution. The aim of this study was to examine these variables when fructose and glucose are added to a semi-solid meal. Seven healthy male participants completed three experimental trials involving the ingestion of 300 mL of semi-skimmed milk mixed with 40 g of instant porridge mix (CON) and with the addition of either 40 g of glucose (GLU) or fructose (FRU). Subjective feelings of appetite were assessed for 2 h after ingestion with blood samples collected at regular intervals. Gastric emptying rate was assessed using the ¹³C breath test method. Half emptying time was not different between trials (CON = 159 ± 51 min; GLU = 197 ± 46 min; FRU = 198 ± 67 min: P = 0.117). No differences were observed for any subjective measurements of appetite (P > 0.05) while blood glucose was elevated (P < 0.05) 20 min after ingestion on both GLU and FRU with this tending to be higher on GLU than FRU. FRU resulted in greater (P < 0.05) blood lactate concentrations than on the other trials. The results of this study demonstrate that gastric emptying rate of glucose and fructose is similar when ingested in a semi-solid meal. In addition, there is little difference in appetite response between these sugars, however, there are some differences in metabolic response which deserve further study.

Timing of post-resistance exercise nutrient ingestion: effects on gastric emptying and glucose and amino acid responses in humans

This study examined the effects of post-resistance exercise protein ingestion timing on the rate of gastric emptying (GE) and blood glucose (BG) and plasma branched-chain amino acid (BCAA) responses. In all, eleven healthy participants randomly ingested 400 ml of a nutrient-rich drink containing 12 g carbohydrates and 20 g protein at rest (Con), at 5 min (post-exercise (PE)-5) or at 30 min (PE-30) after a single bout of strenuous resistance exercises. The first and second sets comprised ten repetitions at 50 % of each participant's one-repetition maximum (1RM). The third, fourth and fifth sets comprised ten repetitions at 75 % of 1RM, and the sixth set involved repeated repetitions until exhaustion. Following ingestion of the nutrient-rich drink, we assessed the GE rate using 13C-sodium acetate breath test and evaluated two parameters according to the T max-calc (time when the recovery per hour is maximised), which is a standard analytical method, and T 1/2 (time when the total cumulative dose of [13CO2] reaches one-half). T max-calc and T 1/2 were slower for the PE-5 condition than for either the PE-30 or Con condition (T max-calc; Con: 53 (sd 7) min, PE-5: 83 (sd 16) min, PE-30: 62 (sd 9) min, T 1/2; Con: 91 (sd 7) min, PE-5: 113 (sd 21) min, PE-30: 91 (sd 11) min, P<0·05). BG and BCAA responses were also slower for the PE-5 condition than for either the PE-30 or Con condition. Ingesting nutrients immediately after strenuous resistance exercise acutely delayed GE, which affected BG and plasma BCAA levels in blood circulation.

Indirect vs direct assessment of gastric emptying: A randomized crossover trial comparing C-isotope breath analysis and MRI

BACKGROUND

Indirect methods to assess gastric emptying (GE), such as ¹³ C breath tests (BT), are commonly used. However, BT usually use a sampling time of 4+ hours. The current study aims to assess the validity of BT for four liquid meals differing in physicochemical properties. To this aim, we compared them to MRI GE-measurements.

METHODS

Fifteen healthy males (age 22.6 ± 2.4 years, BMI 22.6 ± 1.8 kg/m² ) participated in a randomized 2 × 2 crossover experiment. Test foods were liquid meals, which were either thin/thick and 100/500 kcal, labeled with 100 mg of ¹³ C-octanoate. GE was measured with MRI and assessed by ¹³ C recovery from breath. Participants were scanned every 10 minutes and at six time points breath samples were collected up to t = 90 minutes. Two curves were fitted to the data to estimate emptying halftime (t_{50 Ghoos} and t_{50 Bluck} ). T₅₀ times were ranked per participant and compared between methods.

KEY RESULTS

On average, MRI and BT showed similar t₅₀ rankings for the four liquid meals. In comparison to MRI, t_{50 Ghoos} overestimated, while t_{50 Bluck} underestimated GE time_. Moreover, more viscous foods were overestimated. In most participants individual t₅₀ time rankings differed significantly between methods.

CONCLUSIONS & INFERENCES

BT can assess relative emptying differences on group level and collecting breath data for 90 minutes constitutes a lower burden for participants and the research facility. However, BT has severe shortcomings compared to MRI for individual GE assessment. Notably, food matrix effects should be considered when interpreting the results of BT.

13C-Acetic Acid Breath Test Monitoring of Gastric Emptying during Disease Progression in Diabetic Rats

Gastric motility disturbance is commonly found in long-standing hyperglycemia. Both delayed and rapid gastric emptying has been reported in diabetes. However, very few studies have followed the changes in gastric emptying during disease progression in diabetes because of technical limitations. ¹³C-Acetic acid breath test is a validated method which is non-invasive and can be used repeatedly or serially to evaluate gastric emptying changes in animal. We investigated the gastric emptying changes in different stages of diabetes using ¹³C-acetic acid breath test, as well as its related mechanisms involving interstitial cells of Cajal (ICCs), and stem cell factor (SCF) in streptozotocin-induced diabetic rats. The results showed that gastric emptying was accelerated at the early stage (12 weeks of diabetes) whereas intramuscular ICCs (ICC-IM) networks were not different from normal group. At long-term stage (28 weeks of diabetes), gastric emptying had returned to normal pattern with no delayed. ICC-IM networks were decreased in the diabetic group compared to 12th weeks, and were lower than in the normal group at the same time point. SCF levels were constantly high in the diabetic group than in the normal group. This result indicated that ¹³C-acetic acid breath test is useful to track the alteration in gastric emptying during disease progression. The change of gastric emptying was not found to be significantly associated with ICC-IM. Elevated SCF may help to preserve ICC-IM, especially in the early phase of diabetes.

Expert consensus document: Advances in the diagnosis and classification of gastric and intestinal motility disorders

Disturbances of gastric, intestinal and colonic motor and sensory functions affect a large proportion of the population worldwide, impair quality of life and cause considerable health-care costs. Assessment of gastrointestinal motility in these patients can serve to establish diagnosis and to guide therapy. Major advances in diagnostic techniques during the past 5-10 years have led to this update about indications for and selection and performance of currently available tests. As symptoms have poor concordance with gastrointestinal motor dysfunction, clinical motility testing is indicated in patients in whom there is no evidence of causative mucosal or structural diseases such as inflammatory or malignant disease. Transit tests using radiopaque markers, scintigraphy, breath tests and wireless motility capsules are noninvasive. Other tests of gastrointestinal contractility or sensation usually require intubation, typically represent second-line investigations limited to patients with severe symptoms and are performed at only specialized centres. This Consensus Statement details recommended tests as well as useful clinical alternatives for investigation of gastric, small bowel and colonic motility. The article provides recommendations on how to classify gastrointestinal motor disorders on the basis of test results and describes how test results guide treatment decisions.

Gastric emptying rate before and after orthodontic treatment examined with the [13C] breath test: A pilot study

INTRODUCTION

Orthodontic patients with malocclusion have significantly lower masticatory and gastrointestinal digestive function than persons with normal occlusion. Although several studies have suggested that masticatory function is improved after orthodontic treatment, the relationship between such improvement and change in gastrointestinal symptoms has not been quantitatively evaluated. In this study, we aimed to investigate the change in masticatory function and the gastric emptying rate in patients with malocclusion, before and after orthodontic treatment.

METHODS

Seven women with malocclusion, before (pretreatment group) and after orthodontic treatment (posttreatment group), and 7 healthy dentate female volunteers (control group) underwent a ¹³C-acetate breath test (¹³CO₂) with a liquid meal and the color changeable gum test, along with completing the frequency scale for symptoms of gastroesophageal reflux and a questionnaire on food intake. Between-group differences were evaluated.

RESULTS

The pretreatment group had significantly longer maximum ¹³CO₂ exhalation time and lower masticatory function, quantified using a higher red-color value on the gum test and the questionnaire on food intake, than did the posttreatment and control groups. No significant differences were identified between the posttreatment and the control groups.

CONCLUSIONS

We provide evidence of improvement of masticatory function after orthodontic treatment, which was associated with a faster rate of gastric emptying.

Severe Delayed Gastric Emptying Induces Non-acid Reflux up to Proximal Esophagus in Neurologically Impaired Patients

Background/Aims

The aim of this study is to investigate the degree of delayed gastric emptying (DGE) and evaluate how the severity of DGE affects gastroesophageal reflux disease (GERD) in neurologically impaired (NI) patients utilizing 24-hour multichannel intraluminal impedance pH measurements (pH/MII) and ¹³C-acetate breath test (¹³C-ABT) analyses.

Methods

¹³C-ABT and pH/MII were conducted in 26 NI patients who were referred to our institution due to suspected GERD. At first, correlation analyses were performed to investigate the correlation between the ¹³C-ABT parameters and the clinical or pH/MII parameters. Thereafter, all patients were divided into 2 groups (DGE and severe DGE [SDGE] group) according to each cut off half emptying time (t_1/2, 90-170 minutes). Each pH/MII parameter was compared between the 2 groups in each set-up cutoff t_1/2.

Results

The mean t_1/2 of all patients was 215.5 ± 237.2 minutes and the t_1/2 of 24 (92.3%) patients were > 100 minutes. Significant moderate positive correlations were observed between both t_1/2 and lag phase time and the non-acid reflux related parameters. Furthermore, the patients in the SDGE group demonstrated higher non-acid reflux related parameters than those of the DGE groups when the cutoff was t_1/2 ≥ 140 minutes.

Conclusion

The present study demonstrated that GE with t_1/2 ≥ 140 minutes was related to an increase of non-acid exposure reaching up to the proximal esophagus in NI patients, and indicating that NI patients with SDGE might have a high risk of non-acid GERD.

Gender Difference of Gastric Emptying in Healthy Volunteers and Patients with Functional Dyspepsia

BACKGROUND AND AIM

Delayed gastric emptying is one of the reasons why functional dyspepsia (FD) occurs. The 13C-acetate breath test is widely used to evaluate gastric emptying. Nevertheless, the standard value of 13C-acetate breath test has not taken into account the gender difference of gastric emptying among healthy individuals. The main aim of this study was to readjust the standard value of 13C-acetate breath test in the light of gender differences. In addition, we clarified the prevalence and clinical characteristics of delayed gastric emptying in patients with FD using the modified standard values of 13C-acetate breath test.

METHODS

Fifty-two healthy individuals and 126 patients with patients with FD were enrolled. Gastric emptying was evaluated by the 13C-acetate breath test. The cut-off points of Tmax for the diagnosis of delayed gastric emptying were determined on the basis of results from healthy individuals making a distinction of genders. Gastroesophageal reflux symptoms, dyspeptic symptoms, scores of anxiety and depression, age, body mass index (BMI), smoking and alcohol consumption were compared between the delayed gastric emptying group and the non-delayed gastric emptying group.

RESULTS

Since gastric emptying was delayed in healthy women compared with that in healthy men (Tmax, 53.6 ± 19.3 vs. 42.7 ± 16.9 min, p = 0.04), we set the cut-off points of Tmax at 60 min in men and at 75 min in women. In patients with FD, the prevalence of delayed gastric emptying was not different between men and women with the modified standard values of 13C-acetate breath test. (31.0 vs. 27.4%, p = 0.68). BMI was lower in the delayed gastric emptying group than in the non-delayed group among the male patients. Reflux symptoms were more severe in delayed gastric emptying group than in the non-delayed group among the female patients.

CONCLUSION

The standard values of 13C-acetate breath test should be modified bearing the gender difference in mind. It provides us more appropriate information to understand the mechanisms of FD.

Sarcopenia is closely associated with pancreatic exocrine insufficiency in patients with pancreatic disease

BACKGROUND/OBJECTIVES

The loss of skeletal muscle mass (sarcopenia) is associated with the poor prognosis of pancreatic cancer. It has been reported pancreatic exocrine insufficiency (PEI) is associated with serum nutritional markers in chronic pancreatitis. However, there has been no report about the relationship between sarcopenia and PEI. The aim of this study is to determine whether body composition, including skeletal muscle (SM), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), intramuscular adipose tissue content (IMAC), and serum nutritional markers are associated with pancreatic exocrine function in patients with pancreatic disease.

METHODS

Data were collected prospectively on 132 patients with pancreatic disease. SM, SAT, VAT and IMAC were assessed by computed tomography. Patients underwent a ¹³C-labeled mixed triglyceride breath test to measure pancreatic exocrine function. Serum nutritional markers were measured at the same time of ¹³C-labeled mixed triglyceride breath test. Patients were stratified by quartiles according to each body component, and for each component the lowest group was defined as the lowest quartile, treating men and women separately. The lowest group for SM was defined as sarcopenia. PEI was defined as a percentage ¹³CO₂ cumulative dose at 7 h below 5%.

RESULTS

Sarcopenia was associated with PEI in both men (P < 0.001) and women (P = 0.012). Serum albumin was associated with PEI in men only (P = 0.005). Among all patients, sarcopenia (P = 0.001) and serum albumin (P = 0.058) were associated with PEI. On multivariate analysis, only sarcopenia remained independently associated with PEI (P < 0.001).

CONCLUSIONS

Sarcopenia is independently associated with PEI in patients with pancreatic disease.

A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine

Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both wellness and susceptibility to disease. Targeted delivery of drugs to treat specific small intestinal disorders such as small bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the small intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a surrogate labeled test compound is handled and in turn, if delivered locally as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose (13)C sodium acetate ((13)C-acetate), which is a stable isotope probe that once absorbed in the small intestine can be readily measured non-invasively by collection and analysis of (13)CO2 in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series of in vitro and in vivo pig experiments, we assessed the enteric-protective properties of a commercially available polymer EUDRAGIT(®) L100-55 on gelatin capsules and also on DRcaps(®). Test results demonstrated that DRcaps(®) coated with EUDRAGIT(®) L100-55 possessed enhanced enteric-protective properties, particularly in vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine.

Formation of short chain fatty acids by the gut microbiota and their impact on human metabolism

The formation of SCFA is the result of a complex interplay between diet and the gut microbiota within the gut lumen environment. The discovery of receptors, across a range of cell and tissue types for which short chain fatty acids SCFA appear to be the natural ligands, has led to increased interest in SCFA as signaling molecules between the gut microbiota and the host. SCFA represent the major carbon flux from the diet through the gut microbiota to the host and evidence is emerging for a regulatory role of SCFA in local, intermediary and peripheral metabolism. However, a lack of well-designed and controlled human studies has hampered our understanding of the significance of SCFA in human metabolic health. This review aims to pull together recent findings on the role of SCFA in human metabolism to highlight the multi-faceted role of SCFA on different metabolic systems.

Formation of short chain fatty acids by the gut microbiota and their impact on human metabolism

The formation of SCFA is the result of a complex interplay between diet and the gut microbiota within the gut lumen environment. The discovery of receptors, across a range of cell and tissue types for which short chain fatty acids SCFA appear to be the natural ligands, has led to increased interest in SCFA as signaling molecules between the gut microbiota and the host. SCFA represent the major carbon flux from the diet through the gut microbiota to the host and evidence is emerging for a regulatory role of SCFA in local, intermediary and peripheral metabolism. However, a lack of well-designed and controlled human studies has hampered our understanding of the significance of SCFA in human metabolic health. This review aims to pull together recent findings on the role of SCFA in human metabolism to highlight the multi-faceted role of SCFA on different metabolic systems.

[Gastroparesis. Definition, diagnostics, and therapy]

Gastroparesis is characterized by a constellation of upper gastrointestinal symptoms in association with delayed gastric emptying in the absence of mechanical outlet obstruction from the stomach. Major symptoms are nausea, vomiting, early satiety or postprandial fullness, bloating, and abdominal or epigastric pain. Idiopathic, diabetic, and postsurgical causes represent the most common etiologies. Diagnostic procedures for the evaluation of gastroparesis comprise gastric emptying scintigraphy (gold standard), (13)C-octanoate breath testing, and a wireless motility capsule. Management of gastroparesis includes normalization of nutritional state, relief of symptoms, glycemic control, and improvement of gastric emptying. Medical treatment entails use of prokinetic drugs, which are currently the first-line therapy. Nausea and vomiting might be positively influenced by antiemetic drugs. Gastric electronic stimulation and surgical interventions should be used in well-defined patients and represent a therapeutic option in tertiary centers.

Gastric Emptying of Liquids in Children

OBJECTIVES

The present study was performed to determine normal values for gastric half-emptying time (t1/2GE) of liquids in healthy children.

METHODS

Gastric emptying (GE) of a standardized test milk-drink measured with technetium scintigraphy and the C-acetate breath test (C-ABT) was compared in 19 children ages between 4 and 15 years with upper gastrointestinal symptoms. The C-ABT was subsequently used to determine normal values for GE of the same liquid test meal in 133 healthy children ages between 1 and 17 years.

RESULTS

In the group of children with upper gastrointestinal symptoms, the results showed a significant correlation (r = 0.604, P = 0.0006) between t1/2GE measured with both techniques. In the group of healthy children, the results of t1/2GE showed that there was no influence of age, sex, weight, height, and body mass index on GE.

CONCLUSIONS

Normal values for GE of a standardized test milk-drink in healthy children were determined with the C-ABT. This technique is considered reliable and is well accepted by the patients.

Gastric emptying and gastro-oesophageal reflux in children with cystic fibrosis

BACKGROUND

Gastro-oesophageal reflux (GOR) is common in patients with cystic fibrosis (CF). The aim of this study was to investigate the relationship between gastric emptying (GE) and GOR in children with CF.

METHODS

Multichannel intraluminal impedance-pH monitoring (MII-pH) to measure GOR and GE breath test (GEBT) to measure GE were performed in 28 children with symptoms suggestive for GOR disease (GORD) (group 1). GEBT was performed in another 28 children with/without GOR symptoms who agreed to undergo GEBT but not MII-pH (group 2).

RESULTS

In group 1, we found increased acid GOR (AGOR) in 46.4% and delayed GE (DGE) in 21.4% but no relationship between increased AGOR and DGE. There was no DGE in group 2. We found DGE in 10.7% and rapid GE in 12.5% of the whole group.

CONCLUSIONS

Almost half of the children with CF and symptoms suggestive for GORD have increased AGOR and almost a quarter has DGE. However, there was no relation between GOR and GE.