Nausea and vomiting in gastroparesis: similarities and differences in idiopathic and diabetic gastroparesis

Current and emerging pharmacotherapy for the treatment of gastroparesis

INTRODUCTION

Gastroparesis is a chronic disorder characterized by decreased gastric emptying and presents with nausea, vomiting, and abdominal pain which impacts patients' quality of life greatly. The treatment modalities available for gastroparesis have been expanding over the past 2 decades. Currently, there are multiple options available for gastroparesis, albeit with only one FDA-approved medication until June 2021.

AREAS COVERED

We review the different treatments available for gastroparesis and discuss the recently FDA-approved intranasal formulation of metoclopramide. This nasal spray guarantees metoclopramide absorption within 15 min of application bypassing first pass metabolism in the liver and overcoming the limitations of the oral formulation not passing into the small intestine for absorption because of a gastroparetic stomach or a patient unable to take the oral metoclopramide because of nausea and vomiting.

EXPERT OPINION

We now find ourselves in an oasis after spending many years in a 'desert' regarding pharmacologic therapies available for gastroparesis. The expansion of the research involving dopamine receptor antagonists and delving into alternative mechanisms of alleviating gastroparesis symptoms has been crucial in the landscape of gastroparesis. This is especially true as our knowledge of gastroparesis has proven that simply improving gastric emptying does not necessarily translate to clinical improvement.

The Efficacy of Tradipitant in Patients With Diabetic and Idiopathic Gastroparesis in a Phase 3 Randomized Placebo-Controlled Clinical Trial

BACKGROUND

Neurokinin receptor 1 antagonists are effective in reducing nausea and vomiting in chemotherapy-induced emesis. We investigated the safety and efficacy of tradipitant, a neurokinin receptor 1 antagonist, in patients with idiopathic and diabetic gastroparesis.

METHODS

A total of 201 adults with gastroparesis were randomly assigned to oral tradipitant 85 mg (n = 102) or placebo (n = 99) twice daily for 12 weeks. Symptoms were assessed by a daily symptom dairy, Gastroparesis Cardinal Symptom Index scores, and other patient-reported questionnaires. Blood levels were monitored for an exposure-response analysis. The primary outcome was change from baseline to week 12 in average nausea severity, measured by daily symptom diary.

RESULTS

The intention-to-treat (ITT) population did not meet the prespecified primary endpoint at week 12 (difference in nausea severity change drug vs placebo; P = .741) or prespecified secondary endpoints. Post hoc analyses were performed to control for drug exposure, rescue medications, and baseline severity inflation. Subjects with high blood levels of tradipitant significantly improved average nausea severity beginning at early time points (weeks 2-4). In post hoc sensitivity analyses, tradipitant treatment demonstrated strengthened effects, with statistically significant improvements in nausea at week 12.

CONCLUSIONS

Although tradipitant did not reach significance in the ITT population, a pharmacokinetic exposure-response analysis demonstrated significant effects with adequate tradipitant exposure. When accounting for confounding factors such as baseline severity inflation and rescue medication, a statistically significant effect was also observed. These findings suggest that tradipitant has potential as a treatment for the symptom of nausea in gastroparesis. (ClincialTrials.gov, Number: NCT04028492).

Metoclopramide Nasal Spray in Women with Symptomatic Diabetic Gastroparesis: A Randomized, Double-Blind, Placebo-Controlled Phase 3 Study

BACKGROUND & AIMS

Metoclopramide nasal spray (MNS) was developed as an alternative to oral metoclopramide. Prior phase 2 studies demonstrated efficacy in reducing symptoms in women, but not men with diabetic gastroparesis. The aim of this phase 3 study was to further determine the safety and efficacy of MNS compared with placebo in reducing symptoms of diabetic gastroparesis in women.

METHODS

This US multicenter, randomized, double-blind, parallel group study enrolled women aged 18-75 years with diabetic gastroparesis and delayed gastric emptying. Subjects were randomized 1:1 to receive placebo or MNS 10 mg. The primary efficacy end point was change in mean daily Gastroparesis Symptom Assessment total score from baseline to Week 4. The Gastroparesis Symptom Assessment daily diary is a validated patient-reported outcome instrument that averages scores of nausea, early satiety, prolonged fullness, bloating, and upper abdominal pain on a 5-point ordinal scale.

RESULTS

Two hundred and five subjects were randomized to receive placebo (n = 103) or MNS (n = 102). Overall, the MNS group did not experience a significant reduction in symptoms compared with the placebo group from baseline to Week 4 (P = .881). However, subjects with moderate-to-severe symptoms at baseline had a significant treatment effect from Weeks 1 to 3 (P < .05) and experienced a significant reduction in nausea and upper abdominal pain for all 4 weeks versus placebo (P < .05). Treatment-emergent adverse events were primarily mild to moderate with headache and abdominal pain reported most frequently.

CONCLUSIONS

Although the primary end point was not met using all enrolled patients, treatment with MNS provided significant relief for women with moderate-to-severe diabetic gastroparesis symptoms. MNS was well tolerated and demonstrated a similar safety profile to placebo. (ClinicalTrials.gov identifier: NCT02025725.).

Nausea is the only symptom associated with delayed gastric emptying in pediatric functional dyspepsia patients

OBJECTIVES

Functional dyspepsia (FD) is a heterogeneous functional gastrointestinal disorder (FGID) with a highly prevalent symptom complex. The aim of our study is to investigate the relation between symptoms of FD and results of gastric emptying (GE) breath test in children.

METHODS

This study included patients (6-17 years old) presented at the general gastroenterology outpatient clinic with dyspeptic symptoms (Rome IV criteria) and underwent careful history taking with clinical examination. A GE breath test with a 13 C-octanoic acid labeled (250 kcal) solid meal was performed and dyspepsia symptom scores, clarified using pictograms for postprandial fullness, bloating, belching, nausea, vomiting, epigastric pain and burning, were obtained every 15 min ranging from 0 to 4 for a total of 240 min. The severity of the complaints (overall and individual symptoms) as displayed by the symptom questionnaire was compared between normal and delayed GE groups. The relationship between GE time and the severity of FD symptoms was assessed using Mann-Whitney test.

RESULTS

Thirty nine FD patients (55% girls; mean age: 11.9 ± 3.3 years) participated in the study. Of these, 43% had delayed GE. The overall symptom severity in patients with delayed GE was similar to the symptoms of patients with a normal GE rate (149.5 ± 12.7 points vs. 123.9 ± 9.0; p = 0.19). Individual symptoms scores showed only nausea to be significantly increased in the group with delayed GE (21.5 ± 1.9 points vs. 33.2 ± 4.6; p = 0.048, p < 0.1).

CONCLUSION

Especially in children with nausea as presenting symptom of FD, a low threshold should be withheld to perform a GE breath test.

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.

Characteristics and outcomes of patients with gastroparesis using enteral and/or exclusive parenteral nutrition

BACKGROUND

Patients with gastroparesis (Gp) may need enteral nutrition (EN) or exclusive parenteral nutrition (PN). Among patients with Gp, we aimed to (1) identify the frequency of EN and exclusive PN use and (2) explore characteristics of patients using EN and/or exclusive PN compared with those using oral nutrition (ON), including changes over 48 weeks.

METHODS

Patients with Gp underwent history and physical examination, gastric emptying scintigraphy, water load satiety testing (WLST), and questionnaires assessing gastrointestinal symptoms and quality of life (QOL). Patients were observed 48 weeks.

RESULTS

Of 971 patients with Gp (idiopathic, 579; diabetic, 336; post-Nissen fundoplication, 51), 939 (96.7%) were using ON only, 14 (1.4%) using exclusive PN, and 18 (1.9%) using EN. Compared with patients receiving ON, patients receiving exclusive PN and/or EN were younger, had lower body mass index, and had greater symptom severity. Patients receiving exclusive PN and/or EN had lower physical QOL but not mental QOL or Gp-related QOL scores. Patients receiving exclusive PN and/or EN ingested less water during WLST but did not have worse gastric emptying. Of those who had been receiving exclusive PN and/or EN, 50% and 25%, respectively, resumed ON at 48-week follow-up.

CONCLUSIONS

This study describes patients with Gp requiring exclusive PN and/or EN for nutrition support, who represent a small (3.3%) but important subset of patients with Gp. Unique clinical and physiological parameters are associated with this subset and provide insight into the use of nutrition support in Gp.

2023 update on the clinical management of gastroparesis

INTRODUCTION

Gastroparesis is characterized by symptoms suggesting gastric retention of food and objective evidence of delayed gastric emptying in the absence of a mechanical obstruction. Nausea, vomiting, early satiety, and postprandial fullness are the classic symptoms of gastroparesis. Gastroparesis is increasingly encountered by physicians. There are several recognized etiologies of gastroparesis, including diabetic, post-surgical, medication-induced, post-viral, and idiopathic.

AREAS COVERED

A comprehensive literature review was conducted to identify studies discussing gastroparesis management. Dietary modifications, medication adjustments, glucose control, antiemetic agents, and prokinetic agents are all part of gastroparesis management. In this manuscript, we detail treatments evolving for gastroparesis, including nutritional, pharmaceutical, device, and recent advanced endoscopic and surgical therapies. This manuscript concludes with a speculative viewpoint on how the field will evolve in 5 years' time.

EXPERT OPINION

Identification of the dominant symptoms (fullness, nausea, abdominal pain, and heartburn) helps to direct management efforts of the patients. Treatments for refractory (treatment resistant) symptoms may include gastric electric stimulation and intra-pyloric interventions like botulinum toxin and endoscopic pyloromyotomy. Understanding the pathophysiology of gastroparesis, relating pathophysiologic abnormalities to specific symptoms, new efficacious pharmacotherapies, and better understanding of the clinical predictors of response of therapies, are priorities for future research in the field of gastroparesis.

Review article: An analysis of the pharmacological rationale for selecting drugs to inhibit vomiting or increase gastric emptying during treatment of gastroparesis

BACKGROUND

Drugs which can inhibit nausea/vomiting and/or increase gastric emptying are used to treat gastroparesis, mostly 'off-label'. Within each category, they act at different targets and modulate different physiological mechanisms.

AIMS

Address the questions: In gastroparesis, why should blocking one pathway causing vomiting, be more appropriate than another? Why might increasing gastric emptying via one mechanism be more appropriate than another?

METHODS

Drugs used clinically were identified via consensus opinions and reviews, excluding the poorly characterised. Their pharmacology was defined, mapped to mechanisms influencing vomiting and gastric emptying, and rationale developed for therapeutic use.

RESULTS

Vomiting: Rationale for 5-HT₃ , D₂ , H₁ or muscarinic antagonists, and mirtazapine, amitriptyline, nortriptyline, are poor. Arguments for inhibiting central consequences of vagal afferent transmission by NK₁ antagonism are complicated by doubts over effects on nausea. Gastric emptying: Confusion emerges because of side-effects of drugs increasing gastric emptying: Metoclopramide (5-HT₄ agonist, D₂ and 5-HT₃ antagonist; also blocks some emetic stimuli and causes tardive dyskinesia) and Erythromycin (high-efficacy motilin agonist, requiring low doses to minimise side-effects). Limited trials with selective 5-HT₄ agonists indicate variable efficacy.

CONCLUSIONS

Several drug classes inhibiting vomiting have no scientific rationale. NK₁ antagonism has rationale but complicated by limited efficacy against nausea. Studies must resolve variable efficacy of selective 5-HT₄ agonists and apparent superiority over motilin agonists. Overall, lack of robust activity indicates a need for novel approaches targeting nausea (e.g., modulating gastric pacemaker or vagal activity, use of receptor agonists or new targets such as GDF15) and objective assessments of nausea.

Outcomes of Gastroparesis in Hospitalized Patients With Generalized Anxiety Disorder

Background   Gastroparesis is a common gastrointestinal pathology that has been increasing in prevalence and represents a significant cost to the United States healthcare system. Gastroparesis is associated with psychological dysfunction, including generalized anxiety disorder (GAD). GAD is known to be a prevalent and chronic manifestation of anxiety, which has been increasing in prevalence since the year 2020. Despite the association between gastroparesis and GAD, there has been limited research on the possible impact GAD may have on the morbidity and mortality of patients hospitalized for gastroparesis, which is further evaluated in this study.   Methods   Using the Nationwide Inpatient Sample from the year 2014, a retrospective study was conducted to assess the outcomes of hospitalized gastroparesis patients with and without a history of GAD. In this study, the analyzed outcomes included acute kidney injury (AKI), acute respiratory failure, sepsis, acute deep vein thrombosis, myocardial infarction, intestinal obstruction, and inpatient mortality. To assess whether GAD is an independent risk factor for the outcomes, a multivariate logistic regression analysis was used.   Results   There were 22,150 patients with gastroparesis assessed in this study; GAD was found to be a comorbid diagnosis in 4,196 of those patients. In the GAD cohort, there was an elevated risk for AKI (adjusted odds ratio 1.24, p < 0.001). The adjusted odds ratios for acute respiratory failure, sepsis, acute deep vein thrombosis, myocardial infarction, intestinal obstruction, and inpatient mortality did not meet the threshold for statistical significance.   Conclusion   In hospitalized gastroparesis patients, GAD is a risk factor for AKI. This finding may be attributed to prerenal azotemia due to an increased risk of nausea and vomiting associated with GAD, as well as the medications used to treat GAD such as escitalopram and duloxetine. In addition, the dual inflammatory states caused by the co-existence of both GAD and gastroparesis may also have a role in increasing the risk for AKI. The results of this study may become increasingly relevant given the increasing prevalence of GAD. .

Gastroparesis and Functional Dyspepsia: Spectrum of Gastroduodenal Neuromuscular Disorders or Unique Entities?

Gastroparesis is defined by delayed gastric emptying in the absence of mechanical obstruction of the stomach. Patients experience symptoms of nausea, vomiting, abdominal pain, fullness, and early satiety. The recognition of the disorder has progressed due to availability of gastric emptying scintigraphy and advancements made in understanding its pathophysiology and treatment options. The clinical presentation and treatment of gastroparesis overlap with a more commonly recognized disorder of gut-brain interaction, functional dyspepsia. Recent studies have reenergized the discussion whether these two are separate entities or perhaps reflect a spectrum of gastroduodenal neuromuscular disorders. The societal guidelines conflict on the utility of gastric emptying scintigraphy in assessment of patients with upper gastrointestinal symptoms. A better appraisal of similarities and differences between gastroparesis and functional dyspepsia will allow targeted treatment for these disorders. This is particularly important as specific pharmacological and endoscopic treatment options are being developed for gastroparesis which are unlikely to be helpful for functional dyspepsia. This review makes the case for considering these disorders in a spectrum where identification of both would most ideally position us toward providing the optimal clinical care.

Synergistic augmentation of rhythmic myogenic contractions of human stomach by arginine vasopressin and adrenaline: Implications for the induction of nausea

BACKGROUND AND PURPOSE

Nausea is associated with the hormonal secretion of vasopressin and adrenaline, although their actions in inducing nausea is poorly understood. Here, we have investigated their actions on human stomach muscle.

EXPERIMENTAL APPROACH

Muscle strips were suspended in tissue baths and neuronal-/non-neuronally-mediated contractions were measured. Custom software analysed eight motility parameters defining spontaneous phasic non-neuronally mediated contractions. Receptor distributions were assessed by qPCR and immunofluorescence.

KEY RESULTS

V_1A receptors and α₁ -adrenoceptors were located on muscle as well as interstitial cells of Cajal (ICCs). Myogenic contractions of human proximal and distal stomach (respectively, 2.6 ± 0.1 and 2.7 ± 0.0 per minute; n = 44) were larger in the distal area (1.1 ± 0.1 and 5.0 ± 0.1 mN), developing relatively slowly (proximal) or rapidly (distal). Vasopressin caused tonic (proximal) or short-lived (distal) increases in muscle tone and increased myogenic contraction amplitude, frequency and rate (acting at V_1A receptors; thresholds 10^-11 -10^-10  M); by contrast, cholinergically mediated contractions were unaffected. Oxytocin acted similarly to vasopressin but less potently, at OT receptors). Adrenaline increased (10^-10 -10^-5  M; α₁ -adrenoceptors) and decreased (≥10^-6  M; β-adrenoceptors) muscle tone and enhanced/reduced myogenic contractions. Cholinergically mediated contractions were reduced (α₂ -adrenoceptors). Combined, vasopressin (10^-9  M) and adrenaline (10^-8  M) increased muscle tone and phasic myogenic activity in a synergistic manner.

CONCLUSIONS AND IMPLICATIONS

Vasopressin and adrenaline increased human gastric tone and myogenic contraction amplitude, rate of contraction and frequency. In combination, their actions were further increased in a synergistic manner. Such activity may promote nausea.

Progress in Gastroparesis - A Narrative Review of the Work of the Gastroparesis Clinical Research Consortium

The Gastroparesis Clinical Research Consortium is a multicenter coalition created and funded by the National Institutes of Diabetes and Digestive and Kidney Disorders, with a mission to advance understanding of the pathophysiology of gastroparesis and develop an effective treatment for patients with symptomatic gastroparesis. In this review, we summarize the results of the published Gastroparesis Clinical Research Consortium studies as a ready and convenient resource for gastroenterologists and others to provide a clear understanding of the consortium's experience and perspective on gastroparesis and related disorders.

Duodenal Mucosal Expression of COVID-19-Related Genes in Health, Diabetic Gastroenteropathy, and Functional Dyspepsia

CONTEXT

SARS-CoV-2 infects the gastrointestinal tract and may be associated with symptoms that resemble diabetic gastroparesis. Why patients with diabetes who contract COVID-19 are more likely to have severe disease is unknown.

OBJECTIVE

We aimed to compare the duodenal mucosal expression of SARS-CoV-2 and inflammation-related genes in diabetes gastroenteropathy (DGE), functional dyspepsia (FD), and healthy controls.

METHODS

Gastrointestinal transit, and duodenal mucosal mRNA expression of selected genes were compared in 21 controls, 39 DGE patients, and 37 FD patients from a tertiary referral center. Pathway analyses were performed.

RESULTS

Patients had normal, delayed (5 FD [13%] and 13 DGE patients [33%]; P = 0.03 vs controls), or rapid (5 FD [12%] and 5 DGE [12%]) gastric emptying (GE). Compared with control participants, 100 SARS-CoV-2-related genes were increased in DGE (FDR < 0.05) vs 13 genes in FD; 71 of these 100 genes were differentially expressed in DGE vs FD but only 3 between DGE patients with normal vs delayed GE. Upregulated genes in DGE include the SARS-CoV2 viral entry genes CTSL (|Fold change [FC]|=1.16; FDR < 0.05) and CTSB (|FC|=1.24; FDR < 0.05) and selected genes involved in viral replication (eg, EIF2 pathways) and inflammation (CCR2, CXCL2, and LCN2, but not other inflammation-related pathways eg, IL-2 and IL-6 signaling).

CONCLUSION

Several SARS-CoV-2-related genes were differentially expressed between DGE vs healthy controls and vs FD but not between DGE patients with normal vs delayed GE, suggesting that the differential expression is related to diabetes per se. The upregulation of CTSL and CTSB and replication genes may predispose to SARS-CoV2 infection of the gastrointestinal tract in diabetes.

Prevalence and clinical correlates of antinuclear antibody in patients with gastroparesis

BACKGROUND

Autoimmunity may play a role in the pathogenesis of gastroparesis in a subset of patients. Antinuclear antibody (ANA) testing is often used to screen for autoimmune disorders.

AIMS

1) Determine prevalence of a positive ANA in patients with gastroparesis; 2) Describe characteristics of idiopathic gastroparesis patients with positive ANA.

METHODS

Patients were assessed with gastric emptying scintigraphy (GES), symptom assessment via Patient Assessment of Upper GI Symptoms [PAGI-SYM], and blood tests-ANA, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP).

RESULTS

Positive ANA was seen in 148 of 893 (17%) patients with gastroparesis, being similar in idiopathic (16% of 536 patients), T1DM (16% of 162), T2DM (18% of 147), and postfundoplication (19% of 48 patients) gastroparesis. Among 536 patients with idiopathic gastroparesis, ANA titer 1:40-1:80 was seen in 33 (6%) patients, 1:160-1:320 in 36 (7%) patients, and ≥1:640 in 17 (3%) patients. Increasing ANA titer was associated with female gender (p = 0.05), Hispanic ethnicity (p = 0.02), comorbid rheumatoid arthritis (p = 0.02), systemic sclerosis (p = 0.004), and elevated ESR (p = 0.007). ANA positivity was associated with lower total GCSI (p = 0.007) and lower nausea/vomiting subscale (p = 0.0005), but not related to gastric emptying.

CONCLUSIONS

The prevalence of a positive ANA in patients with gastroparesis was high at ~17% and did not differ significantly based on etiology. In idiopathic patients, ANA positivity was associated with rheumatoid arthritis, systemic sclerosis, and elevated ESR. ANA-positive gastroparesis represents a subset who often have other autoimmune symptoms or disorders, but less severe nausea and vomiting.

Adverse Events during Vitreoretinal Surgery under Adequacy of Anesthesia Guidance—Risk Factor Analysis

Vitreoretinal surgeries require the administration of general anesthesia (GA) in selected groups of patients. The administration of intraoperative rescue narcotic analgesia (IRNA) during GA poses the risk of postoperative nausea and vomiting (PONV). The surgical pleth index (SPI), a crucial component of the adequacy of anesthesia (AoA) guidance of GA, optimizes the intraoperative titration of IRNA. The current analysis evaluated the risk factors for the occurrence of PONV and the oculo-cardiac reflex (OCR) in patients undergoing pars plana vitrectomy (PPV) under AoA guidance. In total, 175 patients undergoing PPV were randomly allocated to receive either GA with SPI-guided IRNA administration using fentanyl alone or in addition to different preoperative analgesia techniques. Any incidence of PONV or OCR was recorded. Obesity, overweight, smoking status, motion sickness, postoperative intolerable pain perception, female gender, fluid challenge and arterial hypertension did not correlate with an increased incidence of PONV or OCR under AoA guidance. Diabetes mellitus, regardless of insulin dependence, was found to correlate with the increased incidence of PONV. The AoA regimen including SPI guidance of IRNA presumably created similar conditions for individual subjects, so no risk factors of the occurrence of PONV or OCR were found, except for diabetes mellitus. We recommend using AoA guidance for GA administration to reduce OCR and PONV rates.

Diabetic Gastroenteropathy: Soothe the Symptoms or Unravel a Cure?

Autonomic neuropathy in patients with diabetes mellitus, and especially complications related to gastrointestinal neuropathy, are often overlooked in the clinic. Diabetic gastroenteropathy affects every segment of the gastrointestinal tract and generates symptoms that may include nausea, early satiety, vomiting, abdominal pain, constipation, and diarrhea. Severe cases can be complicated by weight loss, dehydration, and electrolyte disturbances. The pathophysiology is complex, the diagnostics and treatment options are multidisciplinary, and there is generally a lack of evidence for the treatment options. The aims for this review are first to summarize the pathophysiology and describe possible and expected symptoms and complications.Further, we will try to supply the clinician with a straightforward tool for diagnostics, and then, we shall summarize established treatment options, including diet recommendations, pharmacological and non-pharmacological options. Finally, we will explore the multiple possibilities of novel treatment, looking at medications related to the pathophysiology of neuropathy, other manifestations of autonomic neuropathies, and symptomatic treatment for other gastrointestinal disorders, also including new knowledge of endosurgical and neuromodulatory treatment. The overall goal is to increase awareness and knowledge on this frequent diabetic complication and to provide better tools for diagnosis and treatment. Ultimately, we hope to encourage further research in this field, as there are clear shortcomings in terms of biomarkers, pathophysiology, as well as treatment possibilities. In conclusion, diagnosis and management of diabetic gastroenteropathy are challenging and often require multidisciplinary teams and multimodal therapies. Treatment options are sparse, but new pharmacological, endoscopic, and neuromodulatory techniques have shown promising results in initial studies.

Gastroparesis

Gastroparesis is characterized by symptoms suggestive of, and objective evidence of, delayed gastric emptying in the absence of mechanical obstruction. This review addresses the normal emptying of solids and liquids from the stomach and details the myogenic and neuromuscular control mechanisms, including the specialized function of the pyloric sphincter, that result in normal emptying, based predominantly on animal research. A clear understanding of fundamental mechanisms is necessary to comprehend derangements leading to gastroparesis, and additional research on human gastric muscles is needed. The section on pathophysiology of gastroparesis considers neuromuscular diseases that affect nonsphincteric gastric muscle, disorders of the extrinsic neural control, and pyloric dysfunction that lead to gastroparesis. The potential cellular basis for gastroparesis is attributed to the effects of oxidative stress and inflammation, with increased pro-inflammatory and decreased resident macrophages, as observed in full-thickness biopsies from patients with gastroparesis. Predominant diagnostic tests involving measurements of gastric emptying, the use of a functional luminal imaging probe, and high-resolution antral duodenal manometry in characterizing the abnormal motor functions at the gastroduodenal junction are discussed. Management is based on supporting nutrition; dietary interventions, including the physical reduction in particle size of solid foods; pharmacological agents, including prokinetics and anti-emetics; and interventions such as gastric electrical stimulation and pyloromyotomy. These are discussed briefly, and comment is added on the potential for individualized treatments in the future, based on optimal gastric emptying measurement and objective documentation of the underlying pathophysiology causing the gastroparesis.

The antroduodenal transition time is prolonged in adults with type 1 diabetes

BACKGROUND

The gastroparetic syndrome encompasses antral hypomotility, gastric dysrhythmia, impaired antroduodenal coordination, pyloric dysfunction, and abnormal duodenal motility; the last three collectively referred to as pylorospasms. We hypothesized that antroduodenal motility is diminished and transition time is prolonged in adults with type 1 diabetes (T1D) and polyneuropathy.

METHODS

This cross-sectional study included 124 participants, of which 21 were healthy, 53 had T1D and 50 had T1D with distal symmetrical polyneuropathy (T1D + DSPN). We used the wireless motility capsule to assess antroduodenal transition time, gastric emptying time, gastric and small bowel motility indices (MI), and numbers of alkalic/acidic exposures.

RESULTS

In comparison with controls, patients with T1D had prolonged antroduodenal transition time (1.85±1.5 vs. 6.6±4.8 minutes; p=0.02), which was even more pronounced in patients with T1D+DSPN (1.85±1.5 vs. 17.8±28.5 minutes; p<0.008. T1D+DSPN tended to have diminished gastric MI (11.9±2.4 vs. 12.7±1.0, p=0.07) and small bowel MI (13.1±1.4 vs. 13.6±0.6, p=0.05) and experienced more antral/pyloric alkalic episodes (1.2±1.3 vs. 2.0±2.1, p=0.02) compared with controls.

CONCLUSION

The current method may assess a proxy for severity of pylorospasms in patients with diabetes and other diseases associated with upper gastrointestinal motility disorders, which ultimately may optimize future management.

United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on gastroparesis

BACKGROUND

Gastroparesis is a condition characterized by epigastric symptoms and delayed gastric emptying (GE) rate in the absence of any mechanical obstruction. The condition is challenging in clinical practice by the lack of guidance concerning diagnosis and management of gastroparesis.

METHODS

A Delphi consensus was undertaken by 40 experts from 19 European countries who conducted a literature summary and voting process on 89 statements. Quality of evidence was evaluated using grading of recommendations assessment, development, and evaluation criteria. Consensus (defined as ≥80% agreement) was reached for 25 statements.

RESULTS

The European consensus defined gastroparesis as the presence of symptoms associated with delayed GE in the absence of mechanical obstruction. Nausea and vomiting were identified as cardinal symptoms, with often coexisting postprandial distress syndrome symptoms of dyspepsia. The true epidemiology of gastroparesis is not known in detail, but diabetes, gastric surgery, certain neurological and connective tissue diseases, and the use of certain drugs recognized as risk factors. While the panel agreed that severely impaired gastric motor function is present in these patients, there was no consensus on underlying pathophysiology. The panel agreed that an upper endoscopy and a GE test are required for diagnosis. Only dietary therapy, dopamine-2 antagonists and 5-HT₄ receptor agonists were considered appropriate therapies, in addition to nutritional support in case of severe weight loss. No consensus was reached on the use of proton pump inhibitors, other classes of antiemetics or prokinetics, neuromodulators, complimentary, psychological, or more invasive therapies. Finally, there was consensus that gastroparesis adversely impacts on quality of life and healthcare costs and that the long-term prognosis of gastroparesis depends on the cause.

CONCLUSIONS AND INFERENCES

A multinational group of European experts summarized the current state of consensus on definition, symptom characteristics, pathophysiology, diagnosis, and management of gastroparesis.

Factors that contribute to the impairment of quality of life in gastroparesis

BACKGROUND

Understanding factors that impair quality of life (QOL) in gastroparesis is important for clinical management.

AIMS

(a) Determine QOL in patients with gastroparesis; (b) Determine factors that impair QOL.

METHODS

Gastroparetic patientsAQ6 underwent history and questionnaires assessing symptoms (PAGI-SYM and Rome III), QOL (SF-36v2 and PAGI-QOL), depression (Beck Depression Inventory [BDI]), and anxiety (State Trait Anxiety InventoryAQ7).

KEY RESULTS

715 gastroparesis patients (256 diabetic (DG), 459 idiopathic (IG)) were evaluated. SF-36 physical component (PC) score averaged 33.3 ± 10.5; 41% had impaired score <30. SF-36 PC scores were similar between diabetic and idiopathic gastroparesis. Impaired SF-36 PC associated with increased nausea/vomiting and upper abdominal pain subscores, acute onset of symptoms, higher number of comorbidities, use of narcotic pain medications, and irritable bowel syndrome (IBS). SF-36 mental component (MC) score averaged 38.9 ± 13.0; 26% had impaired score <30. Poor SF-36 MC associated with diabetic etiology, higher Beck depression inventory, and state anxiety scores. PAGI-QOL score averaged 2.6 ± 1.1; 50% had a score of <2.6. Low PAGI-QOL associated with higher fullness, bloating, and upper abdominal pain subscores, more depression and Trait anxiety, smoking cigarettes, need for nutritional support, progressively worsening symptoms and periodic exacerbations.

CONCLUSIONS & INFERENCES

Multiple measures show poor QOL present in gastroparesis. Several areas impacted on reduced QOL: (a) Symptoms of nausea, vomiting, and abdominal pain, as well as IBS; (b) Etiology and acute onset and progressively worsening symptoms; (c) Comorbidities and psychological factors such as anxiety and depression; (d) Patient-related factors such as smoking. Targeting the modifiable factors may improve patient outcomes in gastroparesis.

United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on gastroparesis

Background

Gastroparesis is a condition characterized by epigastric symptoms and delayed gastric emptying (GE) rate in the absence of any mechanical obstruction. The condition is challenging in clinical practice by the lack of guidance concerning diagnosis and management of gastroparesis.

Methods

A Delphi consensus was undertaken by 40 experts from 19 European countries who conducted a literature summary and voting process on 89 statements. Quality of evidence was evaluated using grading of recommendations assessment, development, and evaluation criteria. Consensus (defined as ≥80% agreement) was reached for 25 statements.

Results

The European consensus defined gastroparesis as the presence of symptoms associated with delayed GE in the absence of mechanical obstruction. Nausea and vomiting were identified as cardinal symptoms, with often coexisting postprandial distress syndrome symptoms of dyspepsia. The true epidemiology of gastroparesis is not known in detail, but diabetes, gastric surgery, certain neurological and connective tissue diseases, and the use of certain drugs recognized as risk factors. While the panel agreed that severely impaired gastric motor function is present in these patients, there was no consensus on underlying pathophysiology. The panel agreed that an upper endoscopy and a GE test are required for diagnosis. Only dietary therapy, dopamine‐2 antagonists and 5‐HT₄ receptor agonists were considered appropriate therapies, in addition to nutritional support in case of severe weight loss. No consensus was reached on the use of proton pump inhibitors, other classes of antiemetics or prokinetics, neuromodulators, complimentary, psychological, or more invasive therapies. Finally, there was consensus that gastroparesis adversely impacts on quality of life and healthcare costs and that the long‐term prognosis of gastroparesis depends on the cause.

Conclusions and Inferences

A multinational group of European experts summarized the current state of consensus on definition, symptom characteristics, pathophysiology, diagnosis, and management of gastroparesis.

Current knowledge

The epidemiology of gastroparesis is not well known.

Diagnosis and treatment of gastroparesis is challenging due to uncertainties in definition and optimal therapeutic approach.

What is new here

A Delphi panel consisting of 40 experts from 19 European countries established the level of consensus on 89 statements regarding gastroparesis.

The statements reaching consensus serve to guide clinicians in recognizing, diagnosing and treating gastroparesis in clinical practice.

The statements without consensus identify areas in need of future research.

Relationship of motor mechanisms to gastroparesis symptoms: toward individualized treatment

Following a classical paper by Dr. Keith A. Kelly published in this journal, and over the past 40 years, there has been increased understanding of the functions of different regions of the stomach, specifically the fundus, antrum, and pylorus. Several of the important physiological principles were based on in vivo animal studies that led to the appreciation of regional function and control mechanisms. These include the roles of the extrinsic parasympathetic vagal innervation, the gastric enteric nervous system and electrical syncytium consisting of pacemaker cells and smooth muscle cells, and duodenogastric reflexes providing feedback regulation following the arrival of food and hydrogen ions stimulating the release of hormones and vagal afferent mechanisms that inhibit gastric motility and stimulate pyloric contractility. Further insights on the role of regional motor functions in gastric emptying were obtained from observations in patients following diverse gastric surgeries or bariatric procedures, including fundoplication, Billroth I and sleeve gastrectomy, and sleeve gastroplasty. Antropyloroduodenal manometry and measurements of pyloric diameter and distensibility index provided important assessments of the role of antral hypomotility and pylorospasm, and these constitute specific targets for individualized treatment of patients with gastroparesis. Moreover, in patients with upper gastrointestinal symptoms suggestive of gastroparesis, the availability of measurements of gastric accommodation and pharmacological agents to reduce gastric sensitivity or enhance gastric accommodation provide additional specific targets for individualized treatment. It is anticipated that, in the future, such physiological measurements will be applied in patients to optimize choice of therapy, possibly including identifying the best candidate for pyloric interventions.

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.

Body weight in patients with idiopathic gastroparesis

BACKGROUND

The classic clinical picture of gastroparesis is a symptomatic patient losing weight. In addition, a number of patients with delayed gastric emptying are obese and/or gaining weight. Our aim was to investigate the factors impacting body weight in patients with idiopathic gastroparesis.

METHODS

In patients with idiopathic gastroparesis, detailed history and weight were acquired at enrollment and after 48 weeks. Questionnaires assessed symptoms, food intake, physical activity, and quality of life. Patients underwent laboratory testing, gastric emptying scintigraphy, and water load testing.

RESULTS

Of 138 patients with idiopathic gastroparesis, 10% were underweight (BMI < 18.5), 39% were normal weight (BMI 18.5-25), 20% were overweight with BMI 25 to 30 kg/m² , and 29% were obese with BMI > 30 kg/m² . Body weight at enrollment was positively associated with oral caloric consumption (P < .001), following a gastroparesis diet (P = .04), nutrition consultation (P = .001), upper abdominal pain (P = .01); and negatively associated with energy expenditure (P = .05), alcohol use (P = .003) and severity of bloating (P < .001). When followed over 48 weeks, 53% patients stayed stable (within 5% of baseline weight), 30% gained, and 17% lost weight. Weight gain over 48 weeks was positively associated with oral caloric consumption (P = .003) and constipation severity (P = .005) at enrollment, and negatively associated with lower abdominal pain severity (P = .007) at enrollment, and associated with improvement in inability to finish meal score (P < .001) at 48 weeks.

CONCLUSIONS

In this series of patients with idiopathic gastroparesis, 10% were underweight whereas 29% were obese. Over 48 weeks, 30% of patients increased their body weight ≥ 5%. Diet, activity, and symptoms are important factors associated with body weight in patients with idiopathic gastroparesis.

Efficacy and Safety of Tradipitant in Patients With Diabetic and Idiopathic Gastroparesis in a Randomized, Placebo-Controlled Trial

BACKGROUND & AIMS

Treatments are needed for gastroparesis; antagonists of tachykinin receptor 1 (TACR1, also called NK1R) can reduce symptoms of nausea and vomiting. We investigated the safety and efficacy of tradipitant, an antagonist of NK1R, in patients with idiopathic or diabetic gastroparesis.

METHODS

We performed a double-blind trial of 152 adults with gastroparesis at 47 sites in the United States from November 2016 through December 2018. Participants were randomly assigned to groups given oral tradipitant 85 mg (n = 77) or placebo (n = 75) twice daily for 4 weeks. Symptoms were assessed by a daily symptom dairy, Gastroparesis Cardinal Symptom Index scores, and other patient-reported questionnaires. The primary outcome from the intent-to-treat analysis was change from baseline to week 4 in average nausea severity, measured by the Gastroparesis Core Symptom Daily Diary.

RESULTS

Patients receiving tradipitant had a significant decrease in nausea score (reduction of 1.2) at week 4 compared with placebo (reduction of 0.7) (P = .0099) and a significant increase in of nausea-free days at week 4 (28.8% increase on tradipitant vs 15.0% on placebo; P = .0160). Patients with nausea and vomiting at baseline (n = 101) had an even greater decrease in nausea in when given tradipitant (reduction of 1.4) compared with those given placebo (reduction of 0.4) (P < .0001), as well as an increase in nausea-free days at week 4 (32.3% improvement on tradipitant vs 7.6% on placebo; P = .0003). The average nausea score was 1 or less at week 4 in 32.9% of patients given tradipitant compared with 11.8% of patients given placebo (P = .0013). A greater than 1-point improvement in Gastroparesis Cardinal Symptom Index score was observed in 46.6% of patients given tradipitant compared with 23.5% of patients given placebo (P = .0053).

CONCLUSIONS

Tradipitant resulted in statistically and clinically meaningful improvements in nausea and reduced vomiting, compared with placebo, in patients with idiopathic or diabetic gastroparesis. ClinicalTrials.gov, Number: NCT02970968.

The efficacy and safety of acupoint injection for diabetic gastroparesis: A protocol for systematic review and meta-analysis

BACKGROUND

Diabetic gastroparesis (DGP) is one of the common complications of diabetes. Accumulated evidences have shown that acupoint injection is beneficial for the clinical treatment of diabetic gastroparesis. However, there is currently no systematic review to assess this therapy. This program aims to evaluate the effectiveness and safety of this therapy for the patients with DGP.

METHODS AND ANALYSIS

Literature search will be conducted via following electronic bibliographic databases from inception to Aug 2020: the Cochrane Library, PubMed, MEDLINE, Web of Science, EMBASE, Springer, China National Knowledge Infrastructure (CNKI), China Biology Medicine (CBM), Chinese Scientific Journal Database (VIP), Wan-Fang Database. All randomized controlled trials published in English or Chinese related to acupoint injection for DGP will be included. The primary outcome is the total effective rate. The secondary outcomes are the change of motilin and gastrin levels before and after the treatment. Two researchers will be responsible for the selection of study, extraction of data, and assessment of study quality independently. RevMan V5.3 Software will be used for assessing the risk of bias and synthesizing data.

RESULTS

This study will provide a high-quality synthesis of current available evidence for the treatment of DGP with this therapy clinically.

CONCLUSION

The conclusions of our study will provide new evidence to judge whether acupoint injection is an effective intervention for patients suffered from DGP. OSF REGISTRATION NUMBER:: osf.io/ms58j.

Study on the Mechanisms of Banxia Xiexin Decoction in Treating Diabetic Gastroparesis Based on Network Pharmacology

In China, Banxia Xiexin decoction (BXD) is applied to treat diabetic gastroparesis (DGP), but its key active ingredients and mechanisms against DGP are unclear. This study is designated to reveal the molecular mechanisms of BXD in treating DGP by adopting a creative approach known as network pharmacology to explore the active ingredients and therapeutic targets of BXD. In our study, 730 differentially expressed genes of DGP were obtained, and 30 potential targets of BXD against DGP were screened out (including ADRB2, DRD1, FOS, MMP9, FOSL1, FOSL2, JUN, MAP2, DRD2, MYC, F3, CDKN1A, IL6, NFKBIA, ICAM1, CCL2, SELE, DUOX2, MGAM, THBD, SERPINE1, ALOX5, CXCL11, CXCL2, CXCL10, RUNX2, CD40LG, C1QB, MCL1, and ADCYAP1). Based on the findings, BXD contains 60 compounds with therapeutic effect on DGP, including the key active ingredients such as quercetin, wogonin, baicalein, beta-sitosterol, and kaempferol. Sixty-eight pathways including TNF signaling pathway, IL-17 signaling pathway, and AGE-RAGE signaling pathway were significantly enriched. In this study, the mechanisms of BXD in treating DGP are affirmed to be a complex network with multi-target and multi-pathway, which provides a reference for future experimental studies.

PAN-selective inhibition of cAMP-phosphodiesterase 4 (PDE4) induces gastroparesis in mice

Inhibitors of cAMP-phosphodiesterase 4 (PDE4) exert a number of promising therapeutic benefits, but adverse effects, in particular emesis and nausea, have curbed their clinical utility. Here, we show that PAN-selective inhibition of PDE4, but not inhibition of PDE3, causes a time- and dose-dependent accumulation of chow in the stomachs of mice fed ad libitum without changing the animals' food intake or the weight of their intestines, suggesting that PDE4 inhibition impairs gastric emptying. Indeed, PDE4 inhibition induced gastric retention in an acute model of gastric motility that traces the passage of a food bolus through the stomach over a 30 minutes time period. In humans, abnormal gastric retention of food is known as gastroparesis, a syndrome predominated by nausea (>90% of cases) and vomiting (>80% of cases). We thus explored the abnormal gastric retention induced by PDE4 inhibition in mice under the premise that it may represent a useful correlate of emesis and nausea. Delayed gastric emptying was produced by structurally distinct PAN-PDE4 inhibitors including Rolipram, Piclamilast, Roflumilast, and RS25344, suggesting that it is a class effect. PDE4 inhibitors induced gastric retention at similar or below doses commonly used to induce therapeutic benefits (e.g., 0.04 mg/kg Rolipram), thus mirroring the narrow therapeutic window of PDE4 inhibitors in humans. YM976, a PAN-PDE4 inhibitor that does not efficiently cross the blood-brain barrier, induced gastroparesis only at significantly higher doses (≥1 mg/kg). This suggests that PDE4 inhibition may act in part through effects on the autonomic nervous system regulation of gastric emptying and that PDE4 inhibitors that are not brain-penetrant may have an improved safety profile. The PDE4 family comprises four subtypes, PDE4A, B, C, and D. Selective ablation of any of these subtypes in mice did not induce gastroparesis per se, nor did it protect from PAN-PDE4 inhibitor-induced gastroparesis, indicating that gastric retention may result from the concurrent inhibition of multiple PDE4s. Thus, potentially, any of the four PDE4 subtypes may be targeted individually for therapeutic benefits without inducing nausea or emesis. Acute gastric retention induced by PDE4 inhibition is alleviated by treatment with the widely used prokinetic Metoclopramide, suggesting a potential of this drug to alleviate the side effects of PDE4 inhibitors. Finally, given that the cause of gastroparesis remains largely idiopathic, our findings open the possibility that a physiologic or pathophysiologic downregulation of PDE4 activity/expression may be causative in a subset of patients.

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.

Pharmacological Approaches to Diabetic Gastroparesis: A systematic review of randomised clinical trials

Pharmacological interventions of diabetic gastroparesis (DG) constitute an essential element of a patient’s management. This article aimed to systematically review the available pharmacological approaches of DG, including their efficacy and safety. A total of 24 randomised clinical trials (RCTs) that investigated the efficacy and/or safety of medications targeting DG symptoms were identified using several online databases. Their results revealed that metoclopramide was the only approved drug for accelerating gastric emptying and improving disease symptoms. However, this medication may have several adverse effects on the cardiovascular and nervous systems, which might be resolved with a new intranasal preparation. Acceptable alternatives are oral domperidone for patients without cardiovascular risk factors or intravenous erythromycin for hospitalised patients. Preliminary data indicated that relamorelin and prucalopride are novel candidates that have proven to be effective and safe. Future RCTs should be conducted based on unified guidelines using universal diagnostic modalities to reveal reliable and comprehensive outcomes.

Gastroparesis: a turning point in understanding and treatment

Gastroparesis is defined by delayed gastric emptying (GE) and symptoms of nausea, vomiting, bloating, postprandial fullness, early satiety and abdominal pain. Most common aetiologies include diabetes, postsurgical and postinfectious, but in many cases it is idiopathic. Clinical presentation and natural history vary by the aetiology. There is significant morbidity and healthcare utilisation associated with gastroparesis. Mechanistic studies from diabetic animal models of delayed GE as well as human full-thickness biopsies have significantly advanced our understanding of this disorder. An innate immune dysregulation and injury to the interstitial cells of Cajal and other components of the enteric nervous system through paracrine and oxidative stress mediators is likely central to the pathogenesis of gastroparesis. Scintigraphy and ¹³C breath testing provide the most validated assessment of GE. The stagnant gastroparesis therapeutic landscape is likely to soon see significant changes. Relatively newer treatment strategies include antiemetics (aprepitant), prokinetics (prucalopride, relamorelin) and fundic relaxants (acotiamide, buspirone). Endoscopic pyloromyotomy appears promising over the short term, especially for symptoms of nausea and vomiting. Further controlled trials and identification of the appropriate subgroup with pyloric dysfunction and assessment of long-term outcomes are essential. This review highlights the clinical presentation, diagnosis, mechanisms and treatment advancements for gastroparesis.

Association Between Symptoms, Quality of Life, and Gastric Emptying in Dyspeptic Patients

Background/Aims

Association between symptoms, quality of life and gastric emptying in dyspepsia is inconsistent in the literature. The aim of our study is to investigate if gastric emptying is associated with specific symptoms and quality of life in dyspeptic patients.

Methods

We reviewed retrospectively gastric emptying measured by ¹³C-labelled octanoate breath testing for more than 6 hours in 198 consecutive patients with dyspepsia complaints. Gastrointestinal symptoms were assessed using a 5-points Likert scale and by a symptomatic composite score, whereas quality of life was measured by the GIQLI.

Results

In our cohort, 90 patients (45%) had a delayed gastric emptying (half emptying time above 166 minutes when assessed over 6–8 hours). There was no difference in symptoms or quality of life between patients with or without delayed gastric emptying. However, patients with severely delayed gastric emptying (half emptying time above 200 minutes) had increased postprandial fullness (P = 0.012), abdominal pain (P = 0.026), bloating (P = 0.044), early satiety (P = 0.018), symptomatic composite score (P = 0.005), and a lower quality of life (P = 0.018). This association was no longer observed if the calculation of gastric emptying was limited to the first 4-hour samples.

Conclusions

There is no association between symptoms, quality of life and gastric emptying in an overall dyspeptic population. However, there is an association between symptoms, quality of life of delayed gastric emptying in the subgroup of patients with severely delayed gastric emptying. An 8-hour measurement of gastric emptying should be recommended.

Acupoint catgut embedding for diabetic gastroparesis: A protocol of systematic review

BACKGROUND

Diabetic gastroparesis (DG) is a common complication to diabetes mellitus (DM). A lot of clinical researches have focused on acupoint catgut embedding for diabetic gastroparesis. However, there is no systematic review and meta-analysis has been conducted. We aim to systematically review the effect of acupoint catgut embedding on diabetic gastroparesis.

METHODS

The databases including PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Ovid LWW, EMBASE, CNKI, Wanfang Database will be searched. Studies published from the time when the database establishment to July 2019 will be retrieved. Randomized controlled clinical trials and quasi-randomized controlled trials on acupoint catgut embedding for diabetic gastroparesis will be included. The primary outcomes are gastroparesis Cardinal Symptom Index (GCSI) or a similar scale to score dyspeptic symptoms. RevMan V.5.3 software will be used to perform the analyses.

RESULTS

This study will provide a high-quality synthesis of the effectiveness and safety of acupoint catgut embedding for diabetic gastroparesis.

CONCLUSION

This systematic review will provide a high-quality evidence to judge whether the acupoint catgut embedding is beneficial to treat diabetic gastroparesis.

PROSPERO REGISTRATION NUMBER

CRD42019140951.

Abdominal Pain in Patients with Gastroparesis: Associations with Gastroparesis Symptoms, Etiology of Gastroparesis, Gastric Emptying, Somatization, and Quality of Life

Abdominal pain can be an important symptom in some patients with gastroparesis (Gp).

AIMS

(1) To describe characteristics of abdominal pain in Gp; (2) describe Gp patients reporting abdominal pain.

METHODS

Patients with idiopathic gastroparesis (IG) and diabetic gastroparesis (DG) were studied with gastric emptying scintigraphy, water load test, wireless motility capsule, and questionnaires assessing symptoms [Patient Assessment of Upper GI Symptoms (PAGI-SYM) including Gastroparesis Cardinal Symptom Index (GCSI)], quality of life (PAGI-QOL, SF-36), psychological state [Beck Depression Inventory (BDI), State-Trait Anxiety Index (STAI), PHQ-15 somatization scale].

RESULTS

In total, 346 Gp patients included 212 IG and 134 DG. Ninety percentage of Gp patients reported abdominal pain (89% DG and 91% IG). Pain was primarily in upper or central midline abdomen, described as cramping or sickening. Upper abdominal pain was severe or very severe on PAGI-SYM by 116/346 (34%) patients, more often by females than by males, but similarly in IG and DG. Increased upper abdominal pain severity was associated with increased severity of the nine GCSI symptoms, depression on BDI, anxiety on STAI, somatization on PHQ-15, the use of opiate medications, decreased SF-36 physical component, and PAGI-QOL, but not related to severity of delayed gastric emptying or water load ingestion. Using logistic regression, severe/very severe upper abdominal pain associated with increased GCSI scores, opiate medication use, and PHQ-15 somatic symptom scores.

CONCLUSIONS

Abdominal pain is common in patients with Gp, both IG and DG. Severe/very severe upper abdominal pain occurred in 34% of Gp patients and associated with other Gp symptoms, somatization, and opiate medication use. ClinicalTrials.gov Identifier: NCT01696747.

Opioid Use and Potency Are Associated With Clinical Features, Quality of Life, and Use of Resources in Patients With Gastroparesis

BACKGROUND & AIMS

Many patients with gastroparesis are prescribed opioids for pain control, but indications for opioid prescriptions and the relationship of opioid use to gastroparesis manifestations are undefined. We characterized associations of use of potent vs weaker opioids and presentations of diabetic and idiopathic gastroparesis.

METHODS

We collected data on symptoms, gastric emptying, quality of life, and health care resource use from 583 patients with gastroparesis (>10% 4-h scintigraphic retention) from the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Consortium, from January 2007 through November 2016. Patients completed medical questionnaires that included questions about opioid use. The opioid(s) were categorized for potency relative to oral morphine. Symptom severities were quantified by Patient Assessment of Upper Gastrointestinal Disorders Symptoms questionnaires. Subgroup analyses compared patients on potent vs weaker opioids and opioid effects in diabetic vs idiopathic etiologies.

RESULTS

Forty-one percent of patients were taking opioids; 82% of these took potent agents (morphine, hydrocodone, oxycodone, methadone, hydromorphone, buprenorphine, or fentanyl). Abdominal pain was the reason for prescription for 61% of patients taking opioids. Mean scores for gastroparesis, nausea/vomiting, bloating/distention, abdominal pain, and constipation scores were higher in opioid users (P ≤ .05). Opioid use was associated with greater levels of gastric retention, worse quality of life, increased hospitalization, and increased use of antiemetic and pain modulator medications compared with nonusers (P ≤ .03). Use of potent opioids was associated with worse gastroparesis, nausea/vomiting, upper abdominal pain, and quality-of-life scores, and more hospitalizations compared with weaker opioids (tapentadol, tramadol, codeine, or propoxyphene) (P ≤ .05). Opioid use was associated with larger increases in gastric retention in patients with idiopathic vs diabetic gastroparesis (P = .008).

CONCLUSIONS

Opioid use is prevalent among patients with diabetic or idiopathic gastroparesis, and is associated with worse symptoms, delays in gastric emptying, and lower quality of life, as well as greater use of resources. Potent opioids are associated with larger effects than weaker agents. These findings form a basis for studies to characterize adverse outcomes of opioid use in patients with gastroparesis and to help identify those who might benefit from interventions to prevent opioid overuse.

Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms

The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn's disease in a single trial. Pulses of high-frequency current applied to the vagus nerve have been used to block signalling from the stomach to the brain to reduce appetite with variable outcomes. Bioelectric neuromodulation has also been investigated for postoperative ileus, gastroparesis symptoms and constipation in animal models and some clinical trials. The clinical success of this bioelectric neuromodulation therapy might be enhanced through better knowledge of the targeted nerve pathways and their physiological and pathophysiological roles, optimizing stimulation protocols and determining which patients benefit most from this therapy.

Propagation Characteristics of Fasting Duodeno-Jejunal Contractions in Healthy Controls Measured by Clustered Closely-spaced Manometric Sensors

Background/Aims

High-resolution methods have advanced esophageal and anorectal manometry interpretation but are incompletely established for intestinal manometry. We characterized normal fasting duodeno-jejunal manometry parameters not measurable by standard techniques using clustered closely-spaced recordings.

Methods

Ten fasting recordings were performed in 8 healthy controls using catheters with 3–4 gastrointestinal manometry clusters with 1–2 cm channel spacing. Migrating motor complex phase III characteristics were quantified. Spatial-temporal contour plots measured propagation direction and velocity of individual contractions. Coupling was defined by pressure peak continuity within clusters.

Results

Twenty-three phase III complexes (11 antral, 12 intestinal origin) with 157 (95% CI, 104–211) minute periodicities, 6.99 (6.25–7.74) minute durations, 10.92 (10.68–11.16) cycle/minute frequencies, 73.6 (67.7–79.5) mmHg maximal amplitudes, and 4.20 (3.18–5.22) cm/minute propagation velocities were recorded. Coupling of individual contractions was 39.1% (32.1–46.1); 63.0% (54.4–71.6) of contractions were antegrade and 32.8% (24.1–41.5) were retrograde. Individual phase III contractions propagated > 35 fold faster (2.48 cm/sec; 95% CI, 2.25–2.71) than complexes themselves. Phase III complexes beyond the proximal jejunum were longer in duration (P = 0.025) and had poorer contractile coupling (P = 0.025) than proximal complexes. Coupling was greater with 1 cm channel spacing vs 2 cm (P < 0.001).

Conclusions

Intestinal manometry using clustered closely-spaced pressure ports characterizes novel antegrade and retrograde propagation and coupling properties which degrade in more distal jejunal segments. Coupling is greater with more closely-spaced recordings. Applying similar methods to dysmotility syndromes will define the relevance of these methods.

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.

Gastroparesis

Gastroparesis is a disorder characterized by delayed gastric emptying of solid food in the absence of a mechanical obstruction of the stomach, resulting in the cardinal symptoms of early satiety, postprandial fullness, nausea, vomiting, belching and bloating. Gastroparesis is now recognized as part of a broader spectrum of gastric neuromuscular dysfunction that includes impaired gastric accommodation. The overlap between upper gastrointestinal symptoms makes the distinction between gastroparesis and other disorders, such as functional dyspepsia, challenging. Thus, a confirmed diagnosis of gastroparesis requires measurement of delayed gastric emptying via an appropriate test, such as gastric scintigraphy or breath testing. Gastroparesis can have idiopathic, diabetic, iatrogenic, post-surgical or post-viral aetiologies. The management of gastroparesis involves: correcting fluid, electrolyte and nutritional deficiencies; identifying and treating the cause of delayed gastric emptying (for example, diabetes mellitus); and suppressing or eliminating symptoms with pharmacological agents as first-line therapies. Several novel pharmacologic agents and interventions are currently in the pipeline and show promise to help tailor individualized therapy for patients with gastroparesis.

Diabetic gastroparesis: current challenges and future prospects

Diabetic gastroparesis (DMGP) is a condition of delayed gastric emptying after gastric outlet obstruction has been excluded. Symptoms of nausea, vomiting, early satiety, bloating, and abdominal pain are associated with DMGP. Uncontrolled symptoms can lead to overall poor quality of life and financial burdens on the healthcare system. A combination of antiemetics and prokinetics is used in symptom control; metoclopramide is the main prokinetic available for clinical use and is the only U.S. Food and Drug Administration-approved agent in the United States. However, a black box warning in 2009 reporting its association with tardive dyskinesia and recommending caution in chronically using this agent beyond 3 months has decreased its role in clinical practice. There is an unmet need for new prokinetics with good efficacy and safety profiles. Currently, there are several new drugs with different mechanisms of action in the pipeline that are under investigation and show promising preliminary results. Surgically combining gastric electrical stimulation with pyloroplasty is considered "gold" standard. Advances in therapeutic endoscopic intervention with gastric per-oral endoscopic pyloromyotomy have also been shown to improve gastric emptying and gastroparesis (GP) symptoms. In this review, we will comment on the challenges encountered when managing patients with DMGP and provide an update on advances in drug development and endoscopic and surgical interventions.

Rome IV Diagnostic Questionnaire Complements Patient Assessment of Gastrointestinal Symptoms for Patients with Gastroparesis Symptoms

BACKGROUND

Patient assessment of upper gastrointestinal symptoms (PAGI-SYM) questionnaire assesses severity of gastrointestinal symptoms in gastroparesis (Gp), dyspepsia, and gastroesophageal reflux disease. Rome IV Diagnostic Questionnaire (R4DQ), used to diagnose various functional gastrointestinal disorders, may also help to better understand symptoms of Gp.

AIM

To assess patients with Gp comparing PAGI-SYM to R4DQ.

METHODS

Patients with symptoms of Gp referred to our center from May 2016 to January 2018 filled out PAGI-SYM and R4DQ.

RESULTS

Out of 357 patients, 225 had delayed gastric emptying including 121 with idiopathic gastroparesis (IGp), 60 with diabetic gastroparesis (DGp), 25 with atypical Gp, and 19 with postsurgical gastroparesis (PSGp). Using PAGI-SYM, DGp had more severe retching and vomiting compared to IGp. PSGp had more severe upper abdominal pain compared to IGp. Using R4DQ, the average number of Rome IV diagnoses that Gp patients met criteria was 2.1 ± 0.1. Most Gp patients had functional dyspepsia (n = 197, 90.8%) and chronic nausea and vomiting syndrome (CNVS) (n = 181, 83.4%). Postprandial distress syndrome (PDS) was present in 189 patients (88.3%), and epigastric pain syndrome in 126 patients (59.8%). The combination of PDS and CNVS was seen in 76.5% of Gp patients.

CONCLUSIONS

In this study, Gp patients were characterized using the PAGI-SYM and R4DQ. DGp had more severe retching and vomiting, while PSGp had more severe upper abdominal pain. PDS and CNVS were the most prevalent Rome IV diagnoses. The combination of PDS and CNVS was typically seen in patients with Gp. R4DQ can be helpful to characterize Gp patients.

Chronic nausea and vomiting: evaluation and treatment

Nausea is an uneasy feeling in the stomach while vomiting refers to the forceful expulsion of gastric contents. Chronic nausea and vomiting represent a diverse array of disorders defined by 4 weeks or more of symptoms. Chronic nausea and vomiting result from a variety of pathophysiological processes, involving gastrointestinal and non-gastrointestinal causes. The prevalence of chronic nausea and vomiting is unclear, although the epidemiology of specific conditions, such as gastroparesis and cyclic vomiting syndrome, is better understood. The economic impact of chronic nausea and vomiting and effects on quality of life are substantial. The initial diagnostic evaluation involves distinguishing gastrointestinal causes of chronic nausea and vomiting (e.g., gastroparesis, cyclic vomiting syndrome) from non-gastrointestinal causes (e.g., medications, vestibular, and neurologic disorders). After excluding anatomic, mechanical and biochemical causes of chronic nausea and vomiting, gastrointestinal causes can be grouped into two broad categories based on the finding of delayed, or normal, gastric emptying. Non-gastrointestinal disorders can also cause chronic nausea and vomiting. As a validated treatment algorithm for chronic nausea and vomiting does not exist, treatment should be based on a thoughtful discussion of benefits, side effects, and costs. The objective of this monograph is to review the evaluation and treatment of patients with chronic nausea and vomiting, emphasizing common gastrointestinal causes.

Functional dyspepsia and gastroparesis

PURPOSE OF REVIEW

This review summarizes recent progress in the epidemiology, pathophysiology and treatment of functional dyspepsia and gastroparesis.

RECENT FINDINGS

The definition of functional dyspepsia and its subgroups has been revised in the recent Rome IV consensus. In gastroparesis, the symptom pattern and its similarities and differences from functional dyspepsia have been a focus of recent research. In functional dyspepsia, pathophysiological research continued to evaluate gastric sensorimotor dysfunctions, but low-grade inflammatory changes and loss of mucosal integrity in the duodenum is a new topic of intense research. Treatment advances include new prokinetics such as acotiamide and the ghrelin receptor agonist relamorelin. The efficacy of tricyclic antidepressants was recently reviewed and mirtazapine is a new agent used in the treatment of functional dyspepsia and gastroparesis. In gastroparesis, research has focused on the role of macrophages in loss of interstitial cells of Cajal, and on the role of pyloric resistance as a target for therapy, using botulinum toxin injection and gastric per-endoscopic pyloric myotomy.

SUMMARY

The functional dyspepsia definition and subgrouping were updated in the Rome IV consensus. Research focuses on duodenal mucosal alterations in functional dyspepsia and pyloric resistance in gastroparesis. New treatments include novel prokinetics and pylorus-directed interventions.

Intragastric Meal Distribution During Gastric Emptying Scintigraphy for Assessment of Fundic Accommodation: Correlation with Symptoms of Gastroparesis

Impaired fundic accommodation (FA) limits fundic relaxation and the ability to act as a reservoir for food. Assessing intragastric meal distribution (IMD) during gastric emptying scintigraphy (GES) allows for a simple measure of FA. The 3 goals of this study were to evaluate trained readers' (nuclear medicine and radiology physicians) visual assessments of FA from solid-meal GES; develop software to quantify GES IMD; and correlate symptoms of gastroparesis with IMD and gastric emptying. Methods: After training to achieve a consensus interpretation of GES FA, 4 readers interpreted FA in 148 GES studies from normal volunteers and patients. Mixture distribution and κ-agreement analyses were used to assess reader consistency and agreement of scoring of FA. Semiautomated software was used to quantify IMD (ratio of gastric counts in the proximal stomach to those in the total stomach) at 0, 1, 2, 3, and 4 h after ingestion of a meal. Receiver-operating-characteristic analysis was performed to optimize the diagnosis of abnormal IMD at 0 min (IMD⁰) with impaired FA. IMD⁰, GES, water load testing, and symptoms were then compared in 177 patients with symptoms of gastroparesis. Results: Reader pairwise weighted κ-values for the visual assessment of FA averaged 0.43 (moderate agreement) for normal FA versus impaired FA. Readers achieved 84.0% consensus and 85.8% reproducibility in assessing impaired FA. IMD⁰ based on the division of the stomach into proximal and distal halves averaged 0.809 (SD, 0.083) for normal FA and 0.447 (SD, 0.132) (P < 0.01) for impaired FA. On the basis of receiver-operating-characteristic analysis, the optimal cutoff for IMD⁰ discrimination of normal FA from impaired FA was 0.568 (sensitivity, 86.7%; specificity, 91.7%). Of 177 patients with symptoms of gastroparesis, 129 (72.9%) had delayed gastric emptying; 25 (14.1%) had abnormal IMD⁰ Low IMD⁰ (impaired FA) was associated with increased early satiety (P = 0.02). Conclusion: FA can be assessed visually during routine GES with moderate agreement and high reader consistency. Visual and quantitative assessments of FA during GES can yield additional information on gastric motility to help explain patients' symptoms.

Diabetes and the Stomach

OPINION STATEMENT

Longstanding diabetes mellitus (both type 1 and type 2) can impair gastric motor function and cause significant upper gastrointestinal symptoms which significantly degrade quality of life, cause nutritional deficits, and degrade healthcare resource use. The most commonly considered gut complication of diabetes, diabetic gastroparesis, is a syndrome of delayed gastric emptying in the absence of mechanical obstruction which leads to symptoms of nausea, vomiting, postprandial fullness, early satiation, bloating, and upper abdominal pain. Gastroparesis also can lead to loss of glycemic control. A diagnosis of gastroparesis is made by documenting delayed gastric emptying and excluding mechanical obstruction. Gastric emptying scintigraphy is the most commonly utilized test for the diagnosis of gastroparesis but novel tests of gastric function have recently been introduced including the gastric emptying breath test and wireless motility capsule. Management most often is aimed at controlling symptoms, which includes dietary modification, optimization of glycemic control, and medication therapy with prokinetics, antiemetics, and neuromodulatory agents. Endoscopic and/or surgical therapies may be considered for refractory cases of gastroparesis. Recent research has provided new insights into the pathophysiology of this disease and is characterizing potential benefits of novel therapeutic agents which show promise in the treatment of this condition. This article will review the pathophysiology, new insights into disease mechanism, and treatment options for diabetic gastroparesis.