Can symptoms discriminate among those with delayed or normal gastric emptying in dysmotility-like dyspepsia?

Current Concepts in Gastroparesis and Gastric Neuromuscular Disorders-Pathophysiology, Diagnosis, and Management

Upper gastrointestinal concerns including gastroparesis-like symptoms affect a large portion of the population, and determining the culprit condition can be difficult due to largely shared symptoms, clinical course, pathophysiology, and treatment pathways. The understanding of gastric neuromuscular disorders (GNDs) is emerging as a heterogeneous group encompassing conditions from gastroparesis to functional dyspepsia with chronic nausea, early satiety, bloating, or abdominal pain, irrespective of gastric emptying. This article aims to review the current concepts in gastroparesis and GNDs including pathophysiology, diagnosis, and management. While some established standards in their diagnosis and management exist, a number of novel diagnostics are becoming available. Durable therapeutic options are notably limited for such common conditions with chronic and debilitating symptoms, and neuromodulators may play a key role in symptom control, which has been previously under-recognized and underutilized. Advances in both pharmacologic treatment targets as well as noninvasive and invasive interventions and devices show promise in improving the experience of patients with gastroparesis-like symptoms. At this time, treatment of GNDs requires comprehensive multidisciplinary care from providers to achieve successful treatment outcomes.

Symptoms from the Gastroparesis Cardinal Symptom Index and clinical factors associated with delayed gastric emptying in patients with suspected gastroparesis

BACKGROUND

The association between upper gastrointestinal symptoms and delayed gastric emptying (GE) shows conflicting results. This study aimed to assess whether the symptoms of the Gastroparesis Cardinal Symptom Index (GCSI) and/or the scores were associated with the result of GE tests and whether they could predict delayed GE.

METHODS

Patients referred for suspected gastroparesis (GP) were included in a prospective database. Demographical data, medical history, and symptoms of the GCSI score were collected for each patient. A GE scintigraphy was then performed with a 4-hour recording. Delayed GE was defined as a retention rate ≥ 10% at 4 h.

RESULTS

Among 243 patients included in this study, 110 patients (45%) had delayed GE. The mean age (49.9 vs. 41.3 years; p < 0.001) and weight loss (9.4 kg vs. 5.6 kg; p = 0.025) were significantly higher in patients with delayed GE. Patients with diabetes or a history of surgery had a higher prevalence of delayed GE (60% and 78%, respectively) than patients without comorbidity (17%; p < 0.001). The GCSI score was higher in patients with delayed GE (3.06 vs. 2.80; p = 0.045), but no threshold was clinically relevant to discriminate between patients with normal and delayed GE. Only vomiting severity was significantly higher in patients with delayed GE (2.19 vs. 1.57; p = 0.01).

CONCLUSION

GE testing should be considered when there are symptoms such as a higher weight loss, comorbidities (diabetes, and history of surgery associated with GP), and the presence of vomiting. Other symptoms and the GCSI score are not useful in predicting delayed GE.

Comparing the prevalence and association between anxiety, depression and gastrointestinal symptoms in gastroparesis versus functional dyspepsia: A systematic review and meta-analysis

OBJECTIVE

To determine the prevalence and associations between anxiety/depression, and gastrointestinal (GI) symptoms across gastroparesis and functional dyspepsia.

METHODS

Twenty adult studies were identified through systematic searches of three databases (PubMed, CINAHL and PsycINFO) in September 2023. Meta-analysis was performed to estimate the pooled prevalence rates of anxiety and depression across gastroparesis and functional dyspepsia, and to determine whether the associations of anxiety/depression and gastrointestinal (GI) symptoms differ in gastroparesis versus functional dyspepsia.

RESULTS

The overall pooled prevalence rate for anxiety was similar (χ2(1) = 2.45, p = .12) in gastroparesis (49%) and functional dyspepsia (29%). The overall pooled prevalence rate for depression in gastroparesis (39%), and functional dyspepsia (32%) was also similar (χ2(1) = 0.81, p = .37). No significant relationship between anxiety and GI symptoms (r = 0.11) or depression and GI symptoms (r = 0.16) was found in gastroparesis, whilst significant, though weak, positive relationships between anxiety and GI symptoms (r = 0.30) and depression and GI symptoms (r = 0.32) were found in functional dyspepsia. The association between GI symptoms and anxiety, but not depression, across gastroparesis and functional dyspepsia was found to be significant (χ2(1) = 5.22, p = .02).

CONCLUSION

Contributing to ongoing debate as to whether gastroparesis and functional dyspepsia are interchangeable syndromes, this review found that anxiety and depression prevalence was similar in both conditions. Psychological assessment and the utilisation of effective and holistic care in both conditions is therefore warranted.

Gastric emptying during and following resolution of moderate diabetic ketoacidosis in type 1 diabetes: a case series

INTRODUCTION

To use the 'gold standard' technique of scintigraphy to quantify gastric emptying (GE) as soon as practicable during an admission with diabetic ketoacidosis (DKA) and following its resolution at least 7 days later.

RESEARCH DESIGN AND METHODS

Five patients with type 1 diabetes, age 29±12 years; Body Mass Index 23±3 kg/m2; hemoglobin A1c 11.3%±1.9%, were studied during an admission with DKA and following its resolution. Solid and liquid GE were measured using scintigraphy. Solid emptying was assessed via the percentage intragastric retention at 100 min and that of liquid by the 50% emptying time.

RESULTS

There was no difference in either solid or liquid GE at the initial study compared with the follow-up. Median (IQR) solid retention was 47±20 versus 38%±33%, respectively; p=0.31, and time to empty 50% of liquid was 37±25 min versus 35±15 min, p=0.31, at the initial and follow-up GE study, respectively.

CONCLUSIONS

GE of solids and liquids is not affected by moderate DKA, inferring that earlier reintroduction of oral intake may be appropriate.

Prevalence and disease burden of gastroparesis in Asia

Gastroparesis is a gastrointestinal disorder characterized by significant prolongation of gastric emptying time caused by impaired motility of the stomach. Its estimated prevalence is 24.2 per 100 000 people. However, the prevalence of gastroparesis in Asian countries is unknown due to a limited number of epidemiological studies and significant phenotypic variability of the Asian population in these studies. Analysis of previous research on gastroparesis and functional bowel disorders reveals the possibility of an increased prevalence among Asian individuals. A comparison of ethnic constituents between the recent United Kingdom gastroparesis study and its mother database has demonstrated a higher prevalence of gastroparesis among British Asian patients when compared with British Caucasian patients. An estimated gastroparesis prevalence in the Asian population can be calculated by identifying the individuals who are likely to demonstrate a delayed gastric emptying from all diagnosed functional dyspepsia patients. We suggest that gastroparesis tends to be underdiagnosed in Asians due to a lack of studies on gastroparesis in the Asian continent, a lack of knowledge among practitioners, and poor availability of scintigraphy testing as well as limited therapeutic options for this disease. Given the high probability of Asian predominance in gastroparesis and its disease impact on quality of life, epidemiological research focusing on the Asian population is required.

Meal-eating characteristics among patients with symptoms of gastroparesis: Relationships to delays in gastric emptying

BACKGROUND

Patients with symptoms of gastroparesis (Gp) often modify their diets and consume small meals. However, the relationship between patients' eating behavior and their gastric emptying is not well understood. This study describes meal-eating characteristics of patients with Gp symptoms and relates them to severity of emptying delay.

METHODS

Adult patients with Gp symptoms underwent 4-h gastric emptying scintigraphy and completed questionnaires including the Patient Assessment of GI Symptoms, a nutrition and diet questionnaire, and the Meal Patterns Questionnaire.

KEY RESULTS

Of 119 patients with Gp symptoms, 35 had normal gastric emptying (≤10% gastric retention at 4 h), 26 mildly delayed (>10%-20%), 28 moderately delayed (>20%-35%), and 30 severely delayed (>35%). Most patients (85%) reported eating small meals with an average of 2.4 meals per day. The most common reasons for stopping eating a meal were feeling full (83%), nausea (46%), and abdominal pain (31%). As gastric emptying worsened, patients increasingly made diet modifications such as low-fat, low-fiber, Gp diet, oral supplements, and blenderized meals (r = 0.309, p = 0.0007). Postprandial fullness lasted for 351 ± 451 min for patients with severely delayed emptying versus 207 ± 173 min for patients with normal emptying (p = 0.19).

CONCLUSIONS & INFERENCES

Meal-eating characteristics were found to vary with severity of gastric retention. Patients with severely delayed gastric emptying reported the longest duration of postprandial fullness. Dietary modification increased significantly with gastric retention. These meal-eating characteristics are important to understand as they impact on dietary education given to Gp patients for symptom management.

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

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

Meal Eating Characteristics of Patients with Gastroparesis

BACKGROUND

Patients with gastroparesis often consume only small meals due to early satiety.

AIMS

(1) Describe meal eating characteristics of patients with gastroparesis; (2) Relate meal eating characteristics to symptoms, gastric emptying (GE), and body weight.

METHODS

Patients with gastroparesis filled out questionnaires including Patient Assessment of Upper GI Symptoms (PAGI-SYM), and questionnaire about meal habits and body weight. Patients underwent gastric emptying scintigraphy.

RESULTS

Of 192 gastroparesis patients, 93% endorsed early satiety (ES) with severity of 3.7 ± 1.5 (scored from 0-5) and 93% endorsed postprandial fullness (PPF) with severity of 3.9 ± 1.3. Time spent consuming meals averaged 13.6 ± 17.7 min. Main reasons patients stopped eating were fullness (61%), nausea (48%), and abdominal pain (31%). Time spent eating correlated inversely with severity of nausea (r = -0.18, p < 0.05), stomach fullness (r = -0.21, p < 0.01), PPF (r = -0.23, p < 0.01), loss of appetite (r = -0.34, p < 0.01). Postprandial fullness lasted for 316 ± 344 min. Duration of PPF correlated with nausea (r = 0.30, p < 0.01), retching (r = 0.29, p < 0.01), vomiting (r = 0.28, p < 0.01), stomach fullness (r = 0.33, p < 0.01), loss of appetite (r = 0.35, p < 0.01), and constipation (r = 0.27, p < 0.01). Underweight patients had increased inability to finish a normal size meal (p < 0.01), loss of appetite (p < 0.01), and lower abdominal pain/discomfort (p < 0.05). Patients had lost 3.06 ± 10.60 kgs from their baseline weight. Weight loss correlated with nausea (r = 0.26, p < 0.01), ES (r = 0.30, p < 0.01), loss of appetite (r = 0.28, p < 0.01).

CONCLUSIONS

Early satiety and postprandial fullness were common with high severity. The main reasons for meal cessation were early satiety, nausea, and abdominal pain. Body weight and change in body weight were associated with symptoms of gastroparesis.

Postprandial symptoms in patients with symptoms of gastroparesis: roles of gastric emptying and accommodation

Patients often are evaluated for gastroparesis because of symptoms occurring with meals. Gastric emptying scintigraphy (GES) is used for gastroparesis diagnosis, although results are not well correlated with gastroparesis symptoms. The aim of this study is to assess relationships between gastroparesis symptoms, gastric emptying (GE), and gastric accommodation (GA). Patients with symptoms of gastroparesis completed the Patient Assessment of Upper GI Symptoms (PAGI-SYM) and recorded symptoms during GES and water load satiety test (WLST), an indirect assessment for GA. A total of 109 patients with gastroparesis symptoms were assessed. Symptom severity increased after GES meal for stomach fullness, belching, nausea, abdominal burning, and abdominal pain. There was no difference in symptoms after meal between patients with delayed (n = 66) and normal (n = 42) GE. Diabetic patients (n = 26) had greater gastric retention than idiopathic patients (n = 78), but idiopathic patients had greater postprandial nausea, stomach fullness, and abdominal pain. Water consumed during WLST averaged 421 ± 245 mL. Idiopathic patients had greater nausea scores during WLST than diabetic patients. In comparison to those with normal water consumption (≥238 mL; n = 80), patients with impaired water ingestion (<238 mL; n = 26) had increased stomach fullness, early satiety, postprandial fullness, and loss of appetite on PAGI-SYM. Patients with delayed and normal GE had similar symptom profiles during GES and WLST. Idiopathic patients had less gastric retention but more symptoms after GES meal and after WLST compared with diabetic patients. Patients with impaired water consumption during WLST had increased symptoms by PAGI-SYM. These data suggest that impaired GA, rather than GE, may be important in explaining postprandial symptoms in patients with symptoms of gastroparesis.NEW & NOTEWORTHY Patients with delayed and normal gastric emptying (GE) had similar symptom profiles during gastric emptying scintigraphy (GES). Idiopathic patients with symptoms of gastroparesis had less gastric retention by GES; but more symptoms after GES meal and after water load satiety test (WLST) compared with diabetic patients. In patients with symptoms of gastroparesis, symptoms after WLST increased with decreasing water consumption. Early satiety and loss of appetite were associated with decreased water consumption during WLST. Thus, impaired accommodation and perhaps visceral hypersensitivity are important in explaining postprandial symptoms in gastroparesis.

Yeokwisan, a Standardized Herbal Formula, Enhances Gastric Emptying via Modulation of the Ghrelin Pathway in a Loperamide-induced Functional Dyspepsia Mouse Model

Background: Yeokwisan, a standardized herbal formula, has exhibited clinical benefit for patients suffering from refractory functional dyspepsia (FD) in Korea since 2016. However, data about the mechanism of action of this formula are yet not available. Aim of the study: To evaluate and explore the effects of Yeokwisan on gastric emptying, a major symptom of functional dyspepsia, and its underlying mechanisms of action using a mouse model. Materials and methods: BALB/C mice were pretreated with Yeokwisan (100, 200, and 400 mg/kg, po) or mosapride (3 mg/kg, po) for 5 days and then treated with loperamide (10 mg/kg, ip) after 20 h of fasting. A solution of 0.05% phenol red (500 μL) or diet of 5% charcoal (200 μL) was orally administered, followed by assessment of gastric emptying or intestinal transit. Plasma acyl-ghrelin (ELISA), C-kit (immunofluorescence and western blotting), nNOS (western blotting) and gastric contraction- and ghrelin-related gene/protein expression levels were examined in stomach and small intestine tissues. Results: Loperamide injection substantially delayed gastric emptying, while Yeokwisan pretreatment (especially 200 and 400 mg/kg Yeokwisan) significantly attenuated this peristaltic dysfunction, as evidenced by the quantity of phenol red retained in the stomach (p < 0.05 or 0.01) and stomach weight (p < 0.05 or 0.01). The levels of plasma acyl-ghrelin and expression of gastric ghrelin-related genes, such as growth hormone secretagogue receptor (GHSR), ghrelin-O-acyltransferase (GOAT), adrenergic receptor β1 (ADRB1) and somatostatin receptor (SSTR), were significantly normalized (p < 0.05 or 0.01) by Yeokwisan (400 mg/kg). Yeokwisan (400 mg/kg) significantly tempered the loperamide-induced alterations in the c-kit and nNOS levels (p < 0.01) as well as the expression of contraction- and ghrelin-related genes, such as 5-HT4 receptor (5-HT4R), anoctamin-1 (ANO1), ryanodine receptor 3 (RYR3) and smooth muscle myosin light chain kinase (smMLCK), in the stomach, but not in the small intestine. Conclusion: The present results showed the clinical relevance of Yeokwisan, in treating FD, especially in promoting gastric emptying but not small intestinal transit. The main mechanisms corresponding to these effects may involve the modulation of the ghrelin pathway and activation of interstitial cells of Cajal in stomach tissue.

The Usefulness of Symptom-based Subtypes of Functional Dyspepsia for Predicting Underlying Pathophysiologic Mechanisms and Choosing Appropriate Therapeutic Agents

Functional dyspepsia (FD) is considered to be a heterogeneous disorder with different pathophysiological mechanisms or pathogenetic factors. In addition to traditional mechanisms, novel concepts regarding pathophysiologic mechanisms of FD have been proposed. Candidates of therapeutic agents based on novel concepts have also been suggested. FD is a symptom complex and currently diagnosed by symptom-based Rome criteria. In the Rome criteria, symptom-based subtypes of FD including postprandial distress syndrome and epigastric pain syndrome are recommended to be used, based on the assumption that each subtype is more homogenous in terms of underlying pathophysiologic mechanisms than FD as a whole. In this review, the usefulness of symptombased subtypes of FD for predicting underlying pathophysiologic mechanisms and choosing appropriate therapeutic agents was evaluated. Although several classic pathophysiologic mechanisms are suggested to be associated with individual dyspeptic symptoms, symptom-based subtypes of FD are not specific for a certain pathogenetic factor or pathophysiologic mechanism, and may be frequently associated with multiple pathophysiologic abnormalities. Novel concepts on the pathophysiology of FD show complex interactions between pathophysiologic mechanisms and pathogenetic factors, and prediction of underlying mechanisms of individual patients simply by the symptom pattern or symptom-based subtypes may not be accurate in a considerable proportion of cases. Therefore, subtyping by the Rome criteria appears to have limited value to guide therapeutic strategy, suggesting that the addition of objective parameters or subclassification reflecting physiologic or pathologic tests may be necessary for the targeted therapeutic approaches, particularly when therapeutic agents targeting novel mechanisms are available.

Functional dyspepsia in children: A study of pathophysiological factors

BACKGROUND AND AIM

Functional dyspepsia (FD) is common in children, and treatment targeted towards the altered pathophysiology can improve outcome. We evaluated FD children for abnormality of gastric accommodation and emptying, psychological stressors (PS), Helicobacter pylori (HP) infection, and post-infectious FD.

METHODS

Diagnosis of FD was based on ROME III criteria. Clinical evaluation including dyspeptic symptom scoring and assessment for PS was performed. Satiety drink test for gastric accommodation, gastroscopy with biopsy for HP infection, and solid meal gastric emptying were performed. Sixty-seven healthy children were enrolled for assessing PS and satiety drink test.

RESULTS

Fifty-five FD children (33 boys, age 12 [6-18] years) with symptoms for 4 (2-48) months and dyspeptic score of 5 (1-13) were enrolled. PS were more common in FD than in controls (46/55 vs 9/67; P < 0.001). Median satiety drink volume was 360 mL (180-1320 mL); no patients had satiety drink volume of < 5th centile of healthy children. The frequency (98% vs 85%; P = 0.01) and severity (65 [10-175] vs 50 [5-130]; P < 0.001) of postprandial symptoms were higher in FD than in controls. Of the postprandial symptoms, pain (20.3% vs 0%; P = 0.000) was present only in FD. Delayed gastric emptying was present in 6.5%, HP infection in 11%, and post-infectious FD in 13% cases. Etiological factor was identified in 87% children, with 20% having multiple factors.

CONCLUSIONS

Abnormality of gastric sensorimotor function is seen in one-fourth of FD cases. HP infection and post-infectious FD are present in 11% and 13% cases, respectively.

Addition of small-bowel transit scintigraphy to gastric emptying for assessment of patients with upper gastrointestinal symptoms

BACKGROUND

Dyspeptic symptoms are not well correlated with gastric emptying (GE) results.

AIMS

To determine (a) prevalence of delayed SB transit (SBT) in patients undergoing GE scintigraphy for symptoms of gastroparesis; (b) symptoms associated with delayed SBT.

METHODS

Patients with symptoms of gastroparesis underwent combined GE and SBT scintigraphy (GES/SBTS). Patients ingested a mixed solid (S)-liquid (L) meal with egg whites labeled with 500 µCi Tc-99 m sulfur colloid and water with 125 µCi In-111 DTPA. Retained S and L gastric activity and percent of L In-111 activity in terminal ileum (TI) and/or cecum/colon at 6 h were determined. Patient Assessment of Gastrointestinal Symptoms (PAGI-SYM) assessed symptoms from 0 (none) to 5 (very severe).

KEY RESULTS

Of 363 patients, 174 (47.9%) had delayed S GE, 141 (38.8%) delayed L GE, and 70 (19.3%) delayed SBT. Delayed SBT was seen in 24 (6.6%) with normal S GE and 46 (12.7%) with delayed S GE. Patients with isolated delayed SBT had highest symptom scores for postprandial fullness (3.5), stomach fullness (3.4), nausea (3.2), bloating (3.2), compared to isolated delayed S GE who had highest symptom scores for postprandial fullness (3.7), nausea (3.6), stomach fullness (3.4), and early satiety (3.3).

CONCLUSIONS & INFERENCES

Delayed SBT occurred in 19.3% of dyspeptic patients using GES/SBTS. While postprandial and stomach fullness were common to both delayed S GE and delayed SBT, early satiety was associated with delayed S GE whereas bloating was associated with delayed SBT. Thus, SBTS can augment GES to help explain some symptoms associated with dyspepsia and suspected gastroparesis.

Gastroparesis and functional dyspepsia: different diseases or different ends of the spectrum?

PURPOSE OF REVIEW

This review assesses the relationship between gastroparesis and functional dyspepsia, in light of recent research assessing cause, pathophysiology and treatment.

RECENT FINDINGS

The Gastroparesis Cardinal Symptom Index (GCSI) lacks the ability to readily distinguish functional dyspepsia from gastroparesis based on symptoms. Although prior studies found that the extent of delay in gastric emptying did not accurately predict severity of symptoms, when optimally measured, delayed gastric emptying may in fact correlate with gastroparesis symptoms. Enteric dysmotility may be an important risk factor for gastroparesis. Altered central processing may play a role in symptom generation for both gastroparesis and functional dyspepsia based on functional brain MRI. Treatment directed towards reducing low-grade inflammation and improving mucosal barrier function in the duodenum may represent a novel therapeutic target for functional dyspepsia, whereas gastric peroral endoscopy myotomy (G-POEM) remains a promising intervention for refractory gastroparesis.

SUMMARY

Abnormalities on functional MRI of the brain have been identified in patients with functional dyspepsia and gastroparesis. Small bowel dysmotility and duodenal barrier dysfunction have been implicated in the pathophysiology of gastroparesis and functional dyspepsia, respectively. New treatments for functional dyspepsia may target low-grade duodenal inflammation and barrier dysfunction. The pylorus remains a target in gastroparesis.

Autonomic function in gastroparesis and chronic unexplained nausea and vomiting: Relationship with etiology, gastric emptying, and symptom severity

BACKGROUND

Autonomic dysfunction can be present in patients with idiopathic and diabetic gastroparesis. The role of autonomic dysfunction relating to gastric emptying and upper gastrointestinal symptoms in patients with gastroparesis and chronic unexplained nausea and vomiting (CUNV) remains unclear. The aim of our study is to evaluate autonomic function in patients with gastroparesis and CUNV with respect to etiology, gastric emptying and symptom severity.

METHODS

We studied 242 patients with chronic gastroparetic symptoms recruited at eight centers. All patients had a gastric emptying scintigraphy within 6 months of the study. Symptom severity was assessed using the gastroparesis cardinal symptom index. Autonomic function testing was performed at baseline enrollment using the ANX 3.0 autonomic monitoring system which measures heart rate variability and respiratory activity measurements.

KEY RESULTS

Low sympathetic response to challenge (Valsalva or standing) was the most common abnormality seen impacting 89% diabetic and 74% idiopathic patients. Diabetics compared to idiopathics, exhibited greater global hypofunction with sympathetic (OR = 4.7, 95% CI 2.2-10.3; P < .001) and parasympathetic (OR = 7.2, 95% CI 3.4-15.0; P < .001) dysfunction. Patients with delayed gastric emptying were more likely to have paradoxic parasympathetic excessive during sympathetic challenge [(Valsalva or standing) 40% vs. 26%, P = .05]. Patients with more severe symptoms exhibited greater parasympathetic dysfunction compared to those with mild-moderate symptoms: resting sympathovagal balance [LFa/RFa 1.8 (1.0-3.1) vs. 1.2 (0.6-2.3), P = .006)] and standing parasympathetic activity [0.4 (0.1-0.8) vs. 0.6 (0.2-1.7); P = .03].

CONCLUSIONS

Autonomic dysfunction was common in patients with gastroparesis and CUNV. Parasympathetic dysfunction was associated with delayed gastric emptying and more severe upper gastrointestinal symptoms. Conversely, sympathetic hypofunction was associated with milder symptoms.

INFERENCES

Gastroparesis and CUNV may be a manifestation of GI autonomic dysfunction or imbalance, such that sympathetic dysfunction occurs early on in the manifestation of chronic upper GI symptoms, while parasympathetic dysfunction results in more severe symptoms and delayed gastric emptying.

Pathophysiology, Aetiology and Treatment of Gastroparesis

Gastroparesis is characterized by delayed gastric emptying, with symptoms such as nausea, vomiting and abdominal pain, in the absence of mechanical obstruction. In most cases, it is idiopathic although diabetes mellitus is another leading cause. The physiology of gastric emptying is a complex process which is influenced by various inputs including the central nervous system, enteric nervous system and gut hormones. Developments in our understanding of gastroparesis have now demonstrated dysfunction in these systems, thus disrupting normal gastric emptying. Once mechanical obstruction is excluded, gastric scintigraphy remains the gold standard for diagnosis although wireless motility capsule and breath testing are alternative methods for diagnosis. Treatment for gastroparesis is challenging, and widely available therapies are often limited either by their poor evidence for efficacy or concerns over their long-term safety profile. Novel prokinetic agents have shown initial promise in clinical trials, and new endoscopic techniques such as gastric per-oral endoscopic myotomy are emerging. These new treatment modalities may provide an option in refractory gastroparesis with the adage of reduced morbidity compared to surgical treatments.

Duodenal inflammation: an emerging target for functional dyspepsia?

Introduction: Functional dyspepsia (FD) is one of the most common functional gastrointestinal disorders and is classified into postprandial distress and epigastric pain syndrome. Despite the recognition of duodenal inflammation as a potential trigger of symptoms, only limited anti-inflammatory therapies exist.Areas covered: This narrative review summarizes the recent advances in the pathophysiology and treatment of FD; it identifies potential therapeutic targets and gaps in the field. An electronic literature search was conducted in Pubmed up to 31st of December 2019.Expert opinion: There is compelling evidence for the role of duodenal inflammation and the eosinophil-mast cell axis in the pathogenesis of dyspeptic symptoms. Traditional prokinetic drugs and neuromodulators target gastric dysmotility and visceral hypersensitivity but are hampered by limited efficacy and side effects. Independent of acid suppression, the anti-inflammatory action of proton pump inhibitors, which remain the first-line therapy in FD, may also explain their therapeutic effect. Other existing and newly established anti-inflammatory drugs should be investigated while trials including probiotics and selective antibiotics should examine the host microbiome and immune activation. Targeted treatments for potential causes of duodenal pathology, such as impaired permeability and dysbiosis, are likely to emerge in the future.

Wireless motility capsule compared with scintigraphy in the assessment of diabetic gastroparesis

BACKGROUND

Gastroparesis is a potentially severe late complication of diabetes mellitus. Today, delayed gastric emptying (GE) is mandatory for establishing the diagnosis. In this study, we compared wireless motility capsule (WMC) with gastric emptying scintigraphy (GES).

METHODS

Seventy-two patients (49 women) with diabetes mellitus (59 type 1) and symptoms compatible with gastroparesis were prospectively included between 2014 and 2018. Patients were simultaneously examined with GES and WMC. Symptoms were assessed with the Patient Assessment of Upper Gastrointestinal Symptom Severity Index (PAGI-SYM) questionnaire. All patients were on intravenous glucose-insulin infusion during testing.

KEY RESULTS

WMC and GES correlated r = .74, P < .001. Compared to GES, WMC at ordinary cutoff for delayed GE (300 minutes) had a sensitivity of 0.92, specificity 0.73, accuracy 0.80, and Cohen's kappa κ = 0.61 (P < .001). By receiver operating characteristics (ROC), the area under the curve was 0.95 (P < .001). A cutoff value for delayed GE of 385 minutes produced sensitivity 0.92, specificity 0.83, accuracy 0.86, and Cohen's kappa κ = 0.72 (P < .001). Inter-rater reliability for GE time with WMC was r = .996, κ = 0.97, both P < .001. There was no difference in symptom severity between patients with normal and delayed GE.

CONCLUSIONS & INFERENCES

Our findings demonstrate the applicability of WMC as a reliable test to assess gastric emptying in diabetic gastroparesis showing very high inter-observer correlation. By elevating the cutoff value for delayed emptying from 300 to 385 minutes, we found higher specificity without reducing sensitivity.

Novel concepts in the pathophysiology and treatment of functional dyspepsia

Emerging data increasingly point towards the duodenum as a key region underlying the pathophysiology of functional dyspepsia (FD), one of the most prevalent functional GI disorders. The duodenum plays a major role in the control and coordination of gastroduodenal function. Impaired duodenal mucosal integrity and low-grade inflammation have been associated with altered neuronal signalling and systemic immune activation, and these alterations may ultimately lead to dyspeptic symptoms. Likely luminal candidates inducing the duodenal barrier defect include acid, bile, the microbiota and food antigens although no causal association with symptoms has been convincingly demonstrated. Recognition of duodenal pathology in FD will hopefully lead to the discovery of new biomarkers and therapeutic targets, allowing biologically targeted rather than symptom-based therapy. In this review, we summarise the recent advances in the diagnosis and treatment of FD with a focus on the duodenum.

Role of Gastric Emptying in Symptoms of Gastroparesis

The symptoms of gastroparesis, such as nausea, vomiting, postprandial fullness, early satiety and abdominal pain, frequently impair the quality of life of the affected individuals. The diagnosis of gastroparesis is made after structural etiologies are ruled out and an assessment of gastric function shows delayed gastric emptying. The role of the delay in gastric emptying in the pathogenesis of symptoms of gastroparesis has been debated, with some studies suggesting an association between delayed gastric emptying and the upper gastrointestinal symptoms, while others do not. The recent literature supports the importance of using reliable methods to assess gastric emptying, as delay in gastric emptying measured on a reliable test (4-h scintigraphy or breath test) is associated with the severity of upper gastrointestinal symptoms. In addition to measuring total gastric emptying, evaluation of regional gastric retention in the proximal and distal stomach and whole gut transit to assess small intestinal and colonic transit may provide additional useful information in patients with more generalized symptoms of gastrointestinal dysmotility.

An orally administered magnoloside A ameliorates functional dyspepsia by modulating brain-gut peptides and gut microbiota

AIMS

Functional dyspepsia (FD) is very common worldwide with a high prevalence of 10%-30%, and it becomes a heavy burden to patients because of its hard to be cured. In our previous study, phenylethanoid glycosides were found to exist in Houpo, a traditional Chinese medicine commonly used for the treatment of abdominal distention, pain and dyspepsia. In the present study, the effect of magnoloside A (MA), a main phenylethanoid glycoside in Houpo, on FD was firstly evaluated and its potential mechanism was concluded.

MATERIALS AND METHODS

MA was orally administered consequently for 3 weeks, and its effect on a FD rat model established through transient neonatal gastric irritation and mature alternate-day fasting was tested. Levels of brain-gut peptides and inflammatory factors in blood or tissues were determined by ELISA methods. Meanwhile, the gut microbiota was analyzed by 16S rRNA gene sequencing and short chain fat acids were determined by GC/MS.

KEY FINDINGS

MA exhibited anti-FD activities by fastening the delayed gut emptying rate of FD rat and increasing the levels of gastrin, motilin, and calcitonin gene related protein; and decreasing the levels of 5-hydroxytryptamine, nitric oxide synthase, and vasoactive intestinal peptide. On the other hand, MA can modulate the composition of gut microbiota, resulting in the variation of the short chain fat acids.

SIGNIFICANCE

MA ameliorated FD rats by modulating of the secretion of related brain-gut peptides and altering the composition of intestinal microbiota.

Association between delayed gastric emptying and upper gastrointestinal symptoms: a systematic review and meta-analysis

BACKGROUND

The relationship between delayed gastric emptying and upper GI symptoms (UGI Sx) is controversial.

OBJECTIVE

To assess association between gastric emptying and UGI Sx, independent of treatment.

DESIGN

We performed a systematic review and meta-analysis of the literature from 2007 to 2017, review of references and additional papers identified by content expert. We included studies evaluating the association between gastric emptying and nausea, vomiting, early satiety/postprandial fullness, abdominal pain and bloating. Covariate analyses included optimal gastric emptying test method, gastric emptying type (breath test or scintigraphy) and patient category. Meta-regression compared the differences based on type of gastric emptying tests.

RESULTS

Systematic review included 92 gastric emptying studies (26 breath test, 62 scintigraphy, 1 ultrasound and 3 wireless motility capsule); 25 of these studies provided quantitative data for meta-analysis (15 scintigraphy studies enrolling 4056 participants and 10 breath test studies enrolling 2231 participants). Meta-regression demonstrated a significant difference between optimal and suboptimal gastric emptying test methods when comparing delayed gastric emptying with nausea and vomiting. On evaluating studies using optimal gastric emptying test methodology, there were significant associations between gastric emptying and nausea (OR 1.6, 95% CI 1.4 to 1.8), vomiting (OR 2.0, 95% CI 1.6 to 2.7), abdominal pain (OR 1.5, 95% CI 1.0 to 2.2) and early satiety/fullness (OR 1.8, 95% CI 1.2 to 2.6) for patients with UGI Sx; gastric emptying and early satiety/fullness in patients with diabetes; gastric emptying and nausea in patients with gastroparesis.

CONCLUSIONS

The systematic review and meta-analysis supports an association between optimally measured delayed gastric emptying and UGI Sx.

A comparison of the diagnosis of gastroparesis in 4 h pediatric gastric emptying studies versus 2 h studies

Background

In adults, there is a consensus for standards to diagnose gastroparesis utilizing a gastric emptying study as the key diagnostic modality but there is no consensus for a standard in pediatrics. Additionally, some cost savings might be achieved if symptoms could be utilized to predict patients with gastroparesis. The aims of the current study were to confirm the sensitivity of a 4 h study in the pediatric population and to assess whether the severity of symptoms were predictive of delayed gastric emptying.

Study

This was a single site, two part study. In the first part, results were reviewed for all patients who had completed a 4-h, solid gastric emptying study over the course of a 3 year period. In the second portion of the study, participants scheduled for a gastric emptying study, completed a modified GCSI questionnaire.

Results

Out of a total of 109 participants, at 2 h, 14 participants (12.8%) had abnormal studies as compared to 26 (23.85%) participants who had abnormal studies at 4 h (p = .0027). Of the 95 participants with normal studies at 2 h, 15% (14/95) were abnormal at 4 h. There were no differences in symptom severity scores between those with slow and those with normal emptying at either 2 h or 4 h.

Conclusions

Our study adds independent confirmation that extending studies from 2 to 4 h increases the diagnostic yield and should be the standard in children and adolescents as it is in adults.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-0948-6) contains supplementary material, which is available to authorized users.

Characterization of Upper Gastrointestinal Symptoms, Gastric Motor Functions, and Associations in Patients with Diabetes at a Referral Center

OBJECTIVES

Our aim was to characterize upper gastrointestinal (UGI) symptoms and associations in individuals with diabetes mellitus (DM) who had undergone evaluation of gastric emptying (GE) and accommodation (GA) at a referral center.

METHODS

From the Mayo Clinic Rochester electronic medical records of adults with diabetes types 1 and 2 (DM1 and DM2) evaluated between January 1997 and December 2015, we extracted demographics, UGI symptoms, current medications, treatments for diabetes, GE solids by scintigraphy, GA by single photon emission computed tomography (SPECT), and diabetes complications. We compared subgroups with delayed (GE at 2 h <25% or GE at 4 h <75%), rapid (GE at 1 h > 35%), and normal GE, as well as reduced (<428 mL) and normal GA.

RESULTS

We reviewed 108 patients (60.2% females, median age 49.0 years). Overall, 71.3% had DM2; one-third of these were insulin dependent and had fairly well-controlled diabetes (median HbA1c 6.7% (IQR 6.2; 7.9)). Manifestations of diabetic triopathy (peripheral neuropathy, nephropathy, and retinopathy) were uncommon at presentation with UGI symptoms. Nausea was the most common symptom (80.6%). There were single or combined GE (total 56%: rapid in 37%, slow in 19%) and GA (total 39%) abnormalities; there was normal GA and GE in 28%; 40.3% of the DM2 patients had accelerated GE at 1 h. GE at 1 h is associated with nausea/vomiting, and fasting gastric volume is associated with bloating.

CONCLUSIONS

Among referred diabetic patients with UGI symptoms, GE and GA testing identifies potential targets for individualizing treatment and avoidance of empirical trials for the 28% with no disturbance of GE and GA.

Postprandial distress syndrome: stratification and management

Functional dyspepsia (FD), defined by the Rome consensus as the presence of functional symptoms originating from the gastroduodenum, is one of the most common functional gastrointestinal disorders. FD is subdivided into postprandial distress syndrome (PDS), with meal-related symptoms such as postprandial fullness and early satiation, and epigastric pain syndrome (EPS), with meal-unrelated symptoms such as epigastric pain or burning. We used a literature search for a narrative review on the current state of knowledge regarding PDS. Areas covered: Epidemiological studies support PDS as a separate entity and the biggest FD subgroup. The pathophysiology of PDS is heterogeneous, and disorders of gastric sensorimotor function as well as low grade duodenal inflammation have been implicated. Although prokinetic agents may provide the most pathophysiology-oriented treatment option, there is a paucity of suitable agents, and proton pump inhibitors are the traditional first-line therapy. Other options include agents that enhance gastric accommodation, such as acotiamide and 5-HT_1A agonists, neuromodulators such as mirtazapine, and traditional medicine approaches. Expert commentary: PDS is highly prevalent, with probably heterogeneous underlying pathophysiology. Motility modifying agents and neuromodulators are the cornerstone of PDS therapy, but there is a need for high quality studies of new therapeutic approaches.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Role of the Duodenum in the Pathogenesis of Functional Dyspepsia: A Paradigm Shift

Functional dyspepsia (FD) is a common disorder characterized by chronic epigastric pain or burning, or bothersome postprandial fullness or early satiation, without a definitive organic cause. The pathogenesis of FD is likely heterogeneous. Classically, motor disorders, visceral hypersensitivity, and brain-gut interactions have been implicated in the pathophysiology of FD, but recently an important role for chronic low-grade inflammation and infection in FD has been reported and confirmed. Duodenal low-grade inflammation is frequently observed in FD in those with and without documented previous gastroenteritis. Duodenal eosinophils and in some cases mast cells may together or separately play a key role, and immune activation (eg, circulating homing small intestinal T cells) has been observed in FD. Low-grade intestinal inflammation in patients with FD may provoke impairment in motor-sensory abnormalities along the gastrointestinal neural axis. Among FD patients, the risk of developing dyspeptic symptoms after a bout of gastroenteritis is 2.54 (95% CI, 1.76–3.65) at more than 6 months after acute gastroenteritis. Gut host and microbial interactions are likely important, and emerging data demonstrate both quantitative and qualitative changes of duodenal mucosal and fecal microbiota in FD. Food antigens (eg, wheat proteins) may also play a role in inducing duodenal inflammation and dyspepsia. While causation is not established, the hypothesis that FD is a disorder of microscopic small intestinal inflammation in a major subset is gaining acceptance, opening the possibility of novel treatment approaches that may be able to alter the natural history of the disorder.

Diabetic Gastroparesis: Principles and Current Trends in Management

This article is a comprehensive review of diabetic gastroparesis, defined as delayed or disordered gastric emptying, including basic principles and current trends in management. This review includes sections on anatomy and physiology, diagnosis and differential diagnosis as well as management and current guidelines for treatment of diabetic gastroparesis. Diabetic gastroparesis (DGp) is a component of autonomic neuropathy resulting from long-standing poorly controlled type 1 and type 2 diabetes. The diagnostic workup of DGp first excludes obstruction and other causes including medications that may mimic delayed/disordered gastric emptying. Targeting nutrition, hydration, symptomatic relief and glycemic control are mainstays of treatment for DGp. Additionally, optimal treatment of DGp includes good glycemic management, often involving customizing insulin delivery using basal-bolus insulin and technology, including sensor-augmented pumps and continuous glucose monitoring systems. Prokinetic medications may be helpful in DGp symptoms, although only limited number of medications is currently available in the USA. Selected medication-refractory patients with DGp may benefit from gastric neuromodulation, and some from surgical interventions including pyloric therapies that can also be done endoscopically. As is true of any of the diabetic complications, prevention of DGp by early and optimal glycemic control is more cost-effective.Funding: Hansa Medcell, India.

Change in Populations of Macrophages Promotes Development of Delayed Gastric Emptying in Mice

BACKGROUND & AIMS

Muscularis propria macrophages lie close to cells that regulate gastrointestinal motor function, including interstitial cells of Cajal (ICC) and myenteric neurons. In animal models of diabetic gastroparesis, development of delayed gastric emptying has been associated with loss of macrophages that express cytoprotective markers and reduced networks of ICC. Mice with long-term diabetes and normal gastric emptying have macrophages that express anti-inflammatory markers and have normal gastric ICC. Mice homozygous for the osteopetrosis spontaneous mutation in the colony-stimulating factor 1 gene (Csf1op/op) do not have macrophages; when they are given streptozotocin to induce diabetes, they do not develop delayed gastric emptying. We investigated whether population of the gastric muscularis propria of diabetic Csf1op/op mice with macrophages is necessary to change gastric emptying, ICC, and myenteric neurons and investigated the macrophage-derived factors that determine whether diabetic mice do or do not develop delayed gastric emptying.

METHODS

Wild-type and Csf1op/op mice were given streptozotocin to induce diabetes. Some Csf1op/op mice were given daily intraperitoneal injections of CSF1 for 7 weeks; gastric tissues were collected and cellular distributions were analyzed by immunohistochemistry. CD45⁺, CD11b⁺, F4/80⁺ macrophages were dissociated from gastric muscularis propria, isolated by flow cytometry and analyzed by quantitative real-time polymerase chain reaction. Cultured gastric muscularis propria from Csf1op/op mice was exposed to medium that was conditioned by culture with bone marrow-derived macrophages from wild-type mice.

RESULTS

Gastric muscularis propria from Csf1op/op mice given CSF1 contained macrophages; 11 of 15 diabetic mice given CSF1 developed delayed gastric emptying and had damaged ICC. In non-diabetic Csf1op/op mice, administration of CSF1 reduced numbers of gastric myenteric neurons but did not affect the proportion of nitrergic neurons or ICC. In diabetic Csf1op/op mice given CSF1 that developed delayed gastric emptying, the proportion of nitrergic neurons was the same as in non-diabetic wild-type controls. Medium conditioned by macrophages previously exposed to oxidative injury caused damage to ICC in cultured gastric muscularis propria from Csf1op/op mice; neutralizing antibodies against IL6R or TNF prevented this damage to ICC. CD45⁺, CD11b⁺, and F4/80⁺ macrophages isolated from diabetic wild-type mice with delayed gastric emptying expressed higher levels of messenger RNAs encoding inflammatory markers (IL6 and inducible nitric oxide synthase) and lower levels of messenger RNAs encoding markers of anti-inflammatory cells (heme oxygenase 1, arginase 1, and FIZZ1) than macrophages isolated from diabetic mice with normal gastric emptying.

CONCLUSIONS

In studies of Csf1op/op and wild-type mice with diabetes, we found delayed gastric emptying to be associated with increased production of inflammatory factors, and reduced production of anti-inflammatory factors, by macrophages, leading to loss of ICC.

Small bowel fed response as measured by wireless motility capsule: Comparative analysis in healthy, gastroparetic, and constipated subjects

BACKGROUND

Small bowel fed response is an increased contractile activity pattern following the ingestion of a meal. Postprandial motility is traditionally evaluated using small bowel manometry. Wireless motility capsule (WMC) is an ingestible wireless capsule that measures pH, temperature, and intraluminal pressure. The primary aim of the study was to assess small bowel fed response captured with the non-invasive WMC. The secondary aim was to compare the fed response patterns between healthy subjects and patients with motility disorders of gastroparesis and constipation.

METHODS

All subjects had 250 cc Ensure^® meal 6 hours after WMC ingestion. Frequency of contractions (Ct), area under the curve (AUC), and motility index (MI) were analyzed during 30 minutes of pre-prandial baseline and 60 minutes postprandially in 20-minute windows.

KEY RESULTS

One hundred and eighty-eight subjects (107 healthy, 23 gastroparetics, 58 constipated) were analyzed. Healthy: Ct, AUC, and MI all increased significantly immediately after meal ingestion (P < .01). Motility parameters peak at 20-40 minutes postmeal. The motor activity decreased at the end of postprandial hour, but was still significantly higher than the fasting baseline (P < .01). Gastroparetics: All motility parameters failed to increase significantly compared to the baseline throughout the entire postprandial hour. Constipated: The fed response was similar to healthy subjects.

CONCLUSIONS AND INFERENCES

The small bowel fed response was readily observed in healthy and chronic constipation subjects with WMC but is blunted in gastroparetics. A blunted small bowel fed response suggests neuropathic changes outside the stomach and may contribute to postprandial symptoms.

Feasibility study of structured diagnosis methods for functional dyspepsia in Korean medicine clinics

Background

Functional dyspepsia (FD) is the seventh most common disease encountered in Korean medicine (KM) clinics. Despite the large number of FD patients visiting KM clinics, the accumulated medical records have no utility in evidence development, due to being unstructured. This study aimed to construct a standard operating procedure (SOP) with appropriate structured diagnostic methods for FD, and assess the feasibility for use in KM clinics.

Methods

Two rounds of professional surveys were conducted by 10 Korean internal medicine professors to select the representative diagnostic methods. A feasibility study was conducted to evaluate compliance and time required for using the structured diagnostic methods by three specialists in two hospitals.

Results

As per the results of the professional survey, five questionnaires and one basic diagnostic method were selected. An SOP was constructed based on the survey results, and a feasibility study showed that the SOP compliance score (out of 5) was 3.45 among the subjects, and 3.25 among the practitioners. The SOP was acceptable and was not deemed difficult to execute. The total execution time was 136.5 minutes, out of which the gastric emptying test time was 129 minutes.

Conclusion

This feasibility study of the SOP with structured diagnostic methods for FD confirmed it was adequate for use in KM clinics. It is expected that these study findings will be helpful to clinicians who wish to conduct observational studies as well as to generate quantitative medical records to facilitate Big Data research.

Gender differences in ghrelin, nociception genes, psychological factors and quality of life in functional dyspepsia

AIM

to evaluate gender differences in the aspect of ghrelin, nociception-related genes and psychological aspects and the quality of life (QoL) in Korean functional dyspepsia (FD) patients.

METHODS

Total of 191 persons were prospectively enrolled between March 2013 and May 2016 in Seoul National Bundang Hospital, and classified into control and FD group based on ROME III criteria. Questionnaire included assessment for dyspepsia symptoms, QoL and anxiety or depression. Preproghrelin and nociception genes in the gastric mucosa and plasma acyl/des-acyl ghrelin were measured.

RESULTS

Lower level of plasma acyl ghrelin in FD patients compared to control was significant only in male (15.9 fmol/mL vs 10.4 fmol/mL, P = 0.017). Significantly higher mRNA expressions of nerve growth factor and transient receptor potential vanilloid receptor 1 were observed in male (P = 0.002 and P = 0.014, respectively) than in female. In contrast, female FD patients had a higher anxiety and depression score than male FD (P = 0.029), and anxiety score was correlated with epigastric pain only in female FD patients (female: Spearman rho = 0.420, P = 0.037). The impairment of overall QoL was more prominent in female FD patients than male patients (5.4 ± 0.3 vs 6.5 ± 0.3, P = 0.020).

CONCLUSION

Gender differences of ghrelin and nociception-related genes in male and psychological factors in female underlie FD symptoms. More careful assessment of psychological or emotional status is required particularly for the female FD patients.

Prevalence of Gastric Motility Disorders in Patients with Functional Dyspepsia

Background/Aims

Gastric motility abnormalities have been considered to be pathophysiological features of functional dyspepsia (FD) that are closely related to dyspepsia symptoms, especially postprandial distress syndrome (PDS). The aims of this study are to (1) investigate the prevalence of gastric motility disorders and (2) evaluate the association between gastric motility abnormalities and dyspeptic symptoms using gastric scintigraphy in the PDS type of FD.

Methods

Forty healthy subjects and 94 PDS type FD patients were enrolled in the study. The volunteers and patients ingested a radiolabeled (technetium-99m) solid test meal, and scintigraphic images were recorded. Gastric accommodation and emptying were assessed by scintigraphic imaging. The patients’ dyspeptic symptoms were also explored using self-completed symptom questionnaires with 10 variables (4 scales, 0–3 points) at the same time.

Results

In 94 Japanese FD patients, the prevalence of impaired gastric accommodation and delayed emptying were 14.9% (14/94) and 10.6% (10/94), respectively. Gastric motility abnormalities were seen in 25.5% (24/94) of FD patients. There was no association between gastric motility abnormalities and dyspeptic symptoms.

Conclusions

Gastric motility abnormalities were seen in 25.5% of Japanese PDS type FD patients. However, there was no association between gastric motility abnormalities and dyspeptic symptoms on gastric scintigraphy.

Polymorphisms of 5-HTT LPR and GNβ3 825C>T and Response to Antidepressant Treatment in Functional Dyspepsia: A Study from The Functional Dyspepsia Treatment Trial

OBJECTIVES

The Functional Dyspepsia Treatment Trial reported that amitriptyline (AMI) was associated with adequate relief of functional dyspepsia (FD) symptoms, but the pharmacogenetics of antidepressant response in FD are not known. GNβ3 825C>T CC genotype has been previously linked to FD and TT genotype to antidepressant response in depression. The ss genotype of the 5-HTT LPR variant of the serotonin transporter gene (SLC6A4) has been linked to selective serotonin reuptake inhibitor (SSRI) response. We aimed to examine whether GNβ3 825C>T and 5-HTT LPR polymorphisms result in differential treatment effects in FD patients receiving antidepressant therapy.

METHODS

Participants were randomized to receive placebo, 50 mg AMI, or 10 mg escitalopram (ESC). The primary end point was adequate relief for ≥5 weeks of the last 10 weeks. Genotyping of GNβ3 825C>T and 5-HTT LPR was performed utilizing PCR-based methods.

RESULTS

GNβ3 825C>T and 5-HTT LPR genotype data were available for 256 (88%) and 246 (84%) patients, respectively. Both polymorphisms were in Hardy-Weinberg equilibrium. In tests for differential treatment, neither 5-HTT LPR nor GNβ3 825C>T genotype influenced response to therapy (P=0.89 and P=0.54, respectively). Although there was a tendency for a more favorable response to ESC in the SS/LS genotype compared to the LL genotype groups (40% vs. 31% reporting adequate relief of FD symptoms) among those in the ESC treatment arm, this was not significant (P=0.43).

CONCLUSIONS

GNβ3 825C>T and 5-HTT LPR genetic variants do not alter treatment response to tricyclic and SSRI antidepressants in FD.

Tumor necrosis factor alpha derived from classically activated "M1" macrophages reduces interstitial cell of Cajal numbers

BACKGROUND

Delayed gastric emptying in diabetic mice and humans is associated with changes in macrophage phenotype and loss of interstitial cells of Cajal (ICC) in the gastric muscle layers. In diabetic mice, classically activated M1 macrophages are associated with delayed gastric emptying, whereas alternatively activated M2 macrophages are associated with normal gastric emptying. This study aimed to determine if secreted factors from M1 macrophages could injure mouse ICC in primary culture.

METHODS

Cultures of gastric ICC were treated with conditioned medium (CM) from activated bone marrow-derived macrophages (BMDMs) and the effect of CM was quantified by counting ICC per high-powered field.

KEY RESULTS

Bone marrow-derived macrophages were activated to a M1 or M2 phenotype confirmed by qRT-PCR. Conditioned medium from M1 macrophages reduced ICC numbers by 41.1%, whereas M2-CM had no effect as compared to unconditioned, control media. Immunoblot analysis of 40 chemokines/cytokines found 12 that were significantly increased in M1-CM, including tumor necrosis factor alpha (TNF-α). ELISA detected 0.697±0.03 ng mL^-1 TNF-α in M1-CM. Recombinant mouse TNF-α reduced Kit expression and ICC numbers in a concentration-dependent manner (EC50 = 0.817 ng mL^-1 ). Blocking M1-CM TNF-α with a neutralizing antibody preserved ICC numbers. The caspase inhibitor Z-VAD.fmk partly preserved ICC numbers (cells/field; 6.63±1.04, 9.82±1.80 w/Z-VAD.fmk, n=6, P<.05).

CONCLUSIONS & INFERENCES

This work demonstrates that TNF-α secreted from M1 macrophages can result in Kit loss and directly injure ICC in vitro partly through caspase-dependent apoptosis and may play an important role in ICC depletion in diabetic gastroparesis.

Prokinetic effects of a new 5-HT4 agonist, YKP10811, on gastric motility in dogs

BACKGROUND AND AIM

Prokinetics have been considered the first-line medicine for treating delayed gastric emptying. The aim of this study was to explore the effects and mechanisms of a new 5-HT₄ receptor agonist, YKP10811, on gastric motility in dogs.

METHODS

Four experiments were performed in dogs: (i) dose-response effects of YKP10811 on liquid gastric emptying; (ii) effects and mechanisms of YKP10811 on solid gastric emptying delayed by glucagon; (iii) effects of low-dose YKP10811 on antral contractions; and (iv) effects of low-dose YKP10811 on gastric accommodation.

RESULTS

No adverse events or cardiac dysrhythmia was noted. (i) High-dose YKP10811 (30 mg/kg) accelerated liquid gastric emptying from 15 to 90 min without inducing adverse events or cardiac dysrhythmia. YKP10811 at low doses (0.3, 1, and 3 mg/kg) accelerated gastric emptying in a dose-dependent manner. (ii) YKP10811 (0.1 mg/kg), but not tegaserod (0.3 mg/kg), significantly accelerated glucagon-induced delayed gastric emptying of solid, and the effect was completely blocked by GR113808. (iii) YKP10811 (0.3 mg/kg) enhanced antral contractions. (iv) YKP10811 did not alter gastric accommodation.

CONCLUSIONS

YKP10811 seems to improve antral contractions and accelerate gastric emptying without altering gastric accommodation in dogs via the 5-HT₄ mechanism and is substantially more potent than tegaserod. No adverse events were noted at a dose 300 times the lowest effective dose. YKP10811 may have a therapeutic potential for gastroparesis.

Upper GI Disorders: Pathophysiology and Current Therapeutic Approaches

Symptoms referable to the upper digestive tract are associated with abnormalities of upper gastric neuromuscular function including abnormalities of motility, sensation, and absorption. Of the upper digestive tract, the stomach is of particular importance in its role in symptom generation and is highlighted in this chapter. Gastric symptoms can be associated with alterations in the rates of gastric emptying, impaired accommodation, heightened gastric sensation, or alterations in gastric myoelectrical activity and contractility. Treatment of gastric neuromuscular disorders requires an understanding of pathophysiology of the disorders, the appropriate use and interpretation of diagnostic tests, and the knowledge of effective treatment options. This chapter covers the pathophysiology and current treatment approaches to disorders of the upper gastrointestinal tract, focusing on classic disorders of the stomach, particularly gastroparesis and functional dyspepsia.

Editorial: Moving Away From Focussing on Gastric Pathophysiology in Functional Dyspepsia: New Insights and Therapeutic Implications

Functional dyspepsia (FD) is a prevalent syndrome that affects up to one in six Americans, although misdiagnosis as gastroesophageal reflux disease may be common. Early satiety, postprandial fullness, and epigastric pain or burning are the cardinal symptoms. Traditionally, FD has been blamed on gastric dysfunction and much research effort has focussed on unlocking the gastric pathophysiology. New research suggests gastric dysfunction has only a minor role in the pathogenesis in many cases, and the focus has begun to shift to evaluation of duodenal feedback and subtle inflammation including duodenal eosinophilia. These new data and the management implications are reviewed.

Chronic Unexplained Nausea and Vomiting or Gastric Neuromuscular Dysfunction (GND)? An Update on Nomenclature, Pathophysiology and Treatment, and Relationship to Gastroparesis

OPINION STATEMENT

Chronic unexplained nausea and vomiting is a debilitating condition that dramatically decreases patient quality of life and creates diagnostic and treatment challenges for healthcare providers. Additionally, the significant overlap in symptoms between disorders such as chronic unexplained nausea and vomiting, gastroparesis, and functional dyspepsia has resulted in a blurring of diagnostic lines and added confusion to the therapeutic approach. The identified overlap in clinical symptoms also suggests a common underlying pathophysiological mechanism may drive these conditions, indicating they could possibly be part of a spectrum of gastric neuromuscular disorders instead of discrete processes. This article will discuss the classification, updates in pathophysiology and therapeutic research, and future directions of research in the treatment of chronic unexplained nausea and vomiting.

Disorders of gastrointestinal hypomotility

Ingestion and digestion of food as well as expulsion of residual material from our gastrointestinal tract requires normal propulsive, i.e. motor, function. Hypomotility refers to inherited or acquired changes that come with decreased contractile forces or slower transit. It not only often causes symptoms but also may compromise nutritional status or lead to other complications. While severe forms, such as pseudo-obstruction or ileus, may have a tremendous functional impact, the less severe forms of hypomotility may well be more relevant, as they contribute to common disorders, such as functional dyspepsia, gastroparesis, chronic constipation, and irritable bowel syndrome (IBS). Clinical testing can identify changes in contractile activity, defined by lower amplitudes or abnormal patterns, and the related effects on transit. However, such biomarkers show a limited correlation with overall symptom severity as experienced by patients. Similarly, targeting hypomotility with pharmacological interventions often alters gut motor function but does not consistently improve symptoms. Novel diagnostic approaches may change this apparent paradox and enable us to obtain more comprehensive information by integrating data on electrical activity, mechanical forces, patterns, wall stiffness, and motions with information of the flow of luminal contents. New drugs with more selective effects or more specific delivery may improve benefits and limit adverse effects. Lastly, the complex regulation of gastrointestinal motility involves the brain-gut axis as a reciprocal pathway for afferent and efferent signaling. Considering the role of visceral input in emotion and the effects of emotion on visceral activity, understanding and managing hypomotility disorders requires an integrative approach based on the mind-body continuum or biopsychosocial model of diseases.

The relationship among gastroparetic symptoms, quality of life, and gastric emptying in patients referred for gastric emptying testing

BACKGROUND

Symptoms suggestive of gastroparesis are non-specific and conflicting reports exist regarding the ability of symptoms to predict the presence of gastroparesis. Our aim, therefore, was to evaluate the relationships between gastroparetic symptoms and their impact on quality of life and determine their relationship with clinical factors and gastric emptying.

METHODS

Gastric emptying scintigraphy, sociodemographic features, health care resource utilization, gastroparetic symptoms, and quality of life using validated questionnaires were obtained from consecutive patients referred for gastric emptying testing (GET). Descriptive analyses were conducted and logistic regression was performed to evaluate associations with abnormal gastric emptying after controlling for other covariates.

KEY RESULTS

Two hundred and sixty-six patients participated (195 females; mean age, 49.1 ± 17.6 years); 75% met Rome III criteria for functional dyspepsia. Gastric emptying was delayed in 28.2% at 4 h; the delay was mild in 48%, moderate in 20% and severe in 32%. Nausea/emesis and postprandial fullness, but not bloating, were significantly greater in those with delayed emptying. Postprandial fullness was most severe. Weak correlations were identified between symptom severity and the severity of gastric emptying delay. Quality of life was also lower in the delayed emptying group. Logistic regression analysis demonstrated associations between delayed gastric emptying and lower quality of life and increased symptom severity.

CONCLUSIONS & INFERENCES

In patients referred for GET, gastroparetic symptoms were more severe in those with delayed emptying. A decrease in quality of life in those with delayed gastric emptying was also present; this was not related to the severity of the delay in gastric emptying.

Therapeutic applications of ghrelin agonists in the treatment of gastroparesis

There remains an unmet need for effective pharmacologic treatments for gastroparesis. Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor and has been shown to regulate energy homeostasis and exert prokinetic effects on gastrointestinal motility. In recent years, several ghrelin receptor agonists have been studied in clinical trials of patients with diabetic gastroparesis. The intravenous macrocyclic peptidomimetic, TZP-101, initially suggested improvement in gastroparesis symptoms with intravenous administration when compared to placebo. However, in subsequent studies of oral preparations, TZP-102 failed to confirm these results. Another ghrelin receptor agonist, RM-131, was recently shown to significantly accelerate gastric emptying (GE) in patients with type 1 and type 2 diabetes and delayed GE. RM-131 reduced total Gastroparesis Cardinal Symptom Index-Daily Diary (GCSI-DD) and composite scores among type 1 diabetics. Continued development of ghrelin agonists should be explored in attempts to expand therapeutic options for the treatment of gastroparesis.

Duodenal rather than antral motility contractile parameters correlate with symptom severity in gastroparesis patients

BACKGROUND

Studies of symptomatic gastroparetics consistently find poor correlation with gastric emptying. We hypothesized that concomitant small bowel dysmotility may play a role in symptom causation in gastroparesis and sought to test this hypothesis by using wireless motility capsule (WMC) testing to simultaneously measure antral and duodenal area under pressure curve (AUC) in patients with delayed gastric emptying.

METHODS

Using a cohort from a multicenter clinical trial and a separate tertiary clinical database, we identified gastroparetics that underwent concurrent WMC testing and completed the Gastroparesis Cardinal Symptom Index, a validated questionnaire. Our study included 35 gastroparetics defined by a gastric emptying time (GET) ≥ 5 h. Antral and duodenal AUC were assessed at 1-h windows pre-GET and post-GET, respectively.

KEY RESULTS

We found moderate correlations between duodenal AUC and symptom severity in the combined cohort (n = 35; R = -0.42; p = 0.01; 95% CI -0.7, -0.1). Removing patients with colonic delay resulted in a stronger correlation of duodenal AUC to symptom severity (n = 21; R = -0.63; p < 0.01; 95% CI -0.81, -0.31). The multicenter trial (n = 20) and clinical practice cohorts (n = 15) had significantly different symptom severity and exclusion criteria. When analyzed separately, significant correlations between duodenal AUC and symptom severity were observed (R = -0.71; p < 0.01; 95% CI -0.9, -0.4 and R = -0.72; p < 0.01; 95% CI -0.9, -0.3, respectively). Symptom severity and antral motility showed no correlation.

CONCLUSIONS & INFERENCES

We found significant correlations between duodenal AUC and symptom severity in two cohorts of gastroparetics. Small bowel motility may contribute to symptom generation in gastroparetic patients and this may inform therapeutic considerations.

Clinical presentation and pathophysiology of gastroparesis

Gastroparesis is a heterogeneous disorder defined by delay in gastric emptying. Symptoms of gastroparesis are nonspecific, including nausea, vomiting, early satiety, bloating, and/or abdominal pain. Normal gastric motor function and sensory function depend on a complex coordination between the enteric and central nervous system. This article discusses the pathophysiology of delayed gastric emptying and the symptoms of gastroparesis, including antropyloroduodenal dysmotility, impaired gastric accommodation, visceral hypersensitivity, and autonomic dysfunction. The underlying pathophysiology of gastroparesis is complex and multifactorial. The article discusses how a combination of these factors leads to symptoms of gastroparesis.

Impact of Overlapping Functional Gastrointestinal Disorders on the Presentation and Quality of Life of Patients with Erosive Esophagitis and Nonerosive Reflux Disease

OBJECTIVE

The aim of this study was to investigate the impact of overlapping functional gastrointestinal disorder (FGID) on the quality of life of patients with nonerosive reflux disease (NERD) and erosive esophagitis (EE).

MATERIALS AND METHODS

Data from patients with NERD and EE were collected between January 2009 and March 2010. These cases were further stratified into the subgroups of overlapping NERD-functional dyspepsia (FD), NERD-irritable bowel syndrome (IBS), EE-FD, EE-IBS, and NERD or EE alone according to the symptoms. All patients completed the modified Chinese GERDQ and the SF-36 questionnaires.

RESULTS

Of the 222 enrolled patients, 96 (43.2%) had NERD and 126 (56.8%) had EE. Overlap of FGID occurred in 43.8-45.8% of the NERD patients, and in 41.3-44.4% of EE cases. The impact of overlapping FGID on patient quality of life was greater in the patients with overlapping NERD-FD compared to those with NERD alone (mean SF-36 total scores 59 vs. 72, adjusted p = 0.025) and the cases with overlapping EE-FD compared to those with EE alone (mean SF-36 total scores 53.19 vs. 73.11, adjusted p = 0.047). There were no significant differences between the individuals with overlapping NERD/EE-IBS and those with NERD/EE alone.

CONCLUSIONS

There was a high prevalence of overlapping FGID, with both FD and IBS, among the GERD patients. The individuals with overlapping GERD and FD had lower quality of life scores than those with GERD alone.

Normal values and symptom correlation of a simplified oatmeal-based gastric emptying study in the Chinese population

BACKGROUND AND AIM

Instant oatmeal has been proposed as a good alternative to the standardized low-fat egg white test meal for gastric emptying studies. We aim to establish normal values of oatmeal-based gastric emptying scintigraphy and test its correlation with gastroparesis symptoms in the Chinese population.

METHODS

This study prospectively enrolled 60 healthy volunteers, 30 functional dyspepsia and 30 diabetes patients with gastroparesis symptoms. All participants were evaluated using the Gastroparesis Cardinal Symptom Index. Each participant ingested instant oatmeal mixed with 1 mCi of (99m) Tc diethylenetriaminepentacetic acid, and serial imaging was immediately acquired for 3 h in the supine position using a left anterior oblique projection. Time-activity curves were generated and quantitative parameters were determined. Normal values were established from healthy volunteers and further applied in the symptomatic patients.

RESULTS

All participants finished the test meal and tolerated the procedure well. All gastric emptying parameters were not significantly affected by age or gender. Values above the 95th percentile of T1/2 , gastric retention at 1, 2, and 3 h (85 min, 65%, 28%, and 8%, respectively) were indicative of delayed gastric emptying. Values below the 5th percentile of gastric retention at 0.5 and 1 h (40% and 15%, respectively) were indicative of rapid gastric emptying. The lower gastric retention limit at 0.5 and 1 h were 40% and 15%, respectively. Four (13.3%) diabetes and four (13.3%) functional dyspepsia patients had delayed emptying while three diabetes patients (10%) had rapid emptying. Gastric emptying parameters correlated best with vomiting (r = 0.621) and nausea (r = 0.566) in diabetes patients.

CONCLUSIONS

We established normal values of oatmeal-based gastric emptying scintigraphy and observed good correlation with cardinal gastroparesis symptoms in the Chinese population.