Efficacy and Safety of Relamorelin in Diabetics With Symptoms of Gastroparesis: A Randomized, Placebo-Controlled Study

Effects of stimulating single acupoint and combination acupoints on diabetic gastroparesis: A randomised controlled trial study

Background and aim

The most effective among the acupoints remains to be determined for treating diabetic gastroparesis (DGP). This study aimed to compare single and combination acupoints for their effectiveness in DGP.

Experimental procedure

A prospective, patient-assessor-blinded randomised controlled trial was designed to compare the efficacy of 8-week acupuncture at a single acupoint (Zhongwan, CV-12), combination acupoints (Zhongwan, CV-12 and Zusanli, ST-36), and a sham-acupoint, in 99 adults with DGP. The primary clinical outcome was measured using the Gastroparesis Cardinal Symptom Index (GCSI), while barium meal examination, fasting plasma glucose, the 2-h plasma glucose, short-form health survey (SF-36), and GCSI subscales were performed for evaluating secondary clinical outcomes. These results were analysed by two factorial analysis of variance (ANOVA) test, Chi-Square, Fisher Exact, Kruskal-Wallis tests and Tukey's Honest Significant Difference (HSD) test.

Results

After randomization, 97 patients completed the study. GCSI scores of all groups decreased during both post-treatment and the follow-up period, they were statistically significant compared to the baseline period (p < 0.01), but there was no significant difference among the groups (p > 0.05) during the post-treatment period. GCSI scores improved more in the combination acupoints group than in the single acupoint group which was better than the sham group after treatment. During the follow-up period, the same trend was observed.

Conclusions

Among patients with DGP, the combination acupoints were more beneficial compared with single and sham acupoints.

Trial registration number

NCT02452489.

The goals for successful development of treatment in gastroparesis

BACKGROUND

Gastroparesis is a motility disorder of the stomach characterized by cardinal symptoms and delayed gastric emptying of solid food in the absence of mechanical obstruction. There is significant unmet need in its management, and essentially there are no medications approved for its treatment over four decades.

PURPOSE

The objectives of this review are to develop an understanding of the goals of treatment, the evidence-based criteria for treatment success based on the current scientific understanding of gastroparesis as well as patient response outcomes, and to propose evidence-based principles for the successful development of treatments for gastroparesis. Specifically, we discuss the pathophysiologic targets in gastroparesis, eligibility criteria for clinical trial participation based on validated gastric emptying studies, and the patient response outcome measures that have been validated to appraise effects of treatment on clinically relevant outcomes. These considerations lead to recommendations regarding eligibility, design, and duration of proof-of-efficacy studies, and to endorsing the American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index Daily Diary as a validated patient response outcome and to justification of the shortening of proof-of-efficacy, placebo-controlled clinical trials to 4 weeks treatment duration after a baseline period. We believe that such approaches will increase the likelihood of successful assessment of efficacy of novel approaches to treating patients with gastroparesis.

Prokinetics-safety and efficacy: The European Society of Neurogastroenterology and Motility/The American Neurogastroenterology and Motility Society expert review

BACKGROUND

Prokinetics are a class of pharmacological drugs designed to improve gastrointestinal (GI) motility, either regionally or across the whole gut. Each drug has its merits and drawbacks, and based on current evidence as high-quality studies are limited, we have no clear recommendation on one class or other. However, there remains a large unmet need for both regionally selective and/or globally acting prokinetic drugs that work primarily intraluminally and are safe and without systemic side effects.

PURPOSE

Here, we describe the strengths and weaknesses of six classes of prokinetic drugs, including their pharmacokinetic properties, efficacy, safety and tolerability and potential indications.

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.

Physiological characterization of gastric emptying using high-resolution antropyloroduodenal manometry

Delayed gastric emptying (GE) has been associated with antral and pyloric dysmotility. We aimed to characterize differences in the antral, duodenal, and pyloric motility profiles associated with delayed GE, using high-resolution antropyloroduodenal manometry (HR-ADM). Patients referred for HR-ADM for dyspeptic symptoms performed a concurrent GE breath test (NCT01519180 and NCT04918329). HR-ADM involved 36 sensors 1 cm apart, placed across the pylorus. Interdigestive and postprandial periods were identified. Antral, pyloric, and duodenal motor profiles were analyzed recording the frequency, amplitude, and propagative nature of contractions for each period. Plots of patients with normal and delayed GE were compared. Sixty patients underwent both HR-ADM and GE tests. Twenty-five and 35 patients had delayed and normal GE, respectively. Antral and duodenal motor profiles were not different between the two groups during the interdigestive period. During the postprandial period, a lower frequency of antral contractions was associated with delayed GE (2.22 vs. 1.39 contractions/min; P = 0.002), but no difference in mean contraction amplitude was observed. The pyloric region was identified in all the patients and pylorospasms, defined as 3 min of repeated isolated pyloric contractions, were more frequent in patients with delayed GE (32.0% vs. 5.7%; P = 0.02) during the postprandial period. No difference in duodenal contraction profiles was observed. Manometric profile alterations were observed in 72% of the patients with delayed GE, with 56% having a low frequency of antral contractions. Using HR-ADM, patients with delayed GE displayed different postprandial antropyloric motility as compared with patients with normal GE.NEW & NOTEWORTHY High-resolution antropyloroduodenal manometry (HR-ADM) allows precise characterization of antral, pyloric, and duodenal motility, although its association with gastric emptying (GE) has been poorly investigated. Concurrent HR-ADM with GE measurement showed a lower frequency of antral postprandial contractions and an increased frequency of postprandial pylorospasms in patients with delayed GE. HR-ADM could, therefore, be useful in the future to better select patients for treatments targeting the pylorus.

A Randomized, Controlled Trial of Efficacy and Safety of Cannabidiol in Idiopathic and Diabetic Gastroparesis

BACKGROUND & AIMS

Cannabis (delta-9-tetrahydrocannabinol), a nonselective cannabinoid-receptor agonist, relieves nausea and pain. Cannabidiol (CBD), a cannabinoid receptor 2 inverse agonist with central effects, also reduces gut sensation and inflammation. We compared the effects of 4 weeks of treatment with pharmaceutical CBD vs placebo in patients with idiopathic or diabetic (diabetes mellitus) gastroparesis.

METHODS

We performed a randomized, double-blinded, placebo-controlled study of CBD twice daily (Epidiolex escalated to 20 mg/kg/d; Jazz Pharmaceuticals, Dublin, Ireland) in patients with nonsurgical gastroparesis with delayed gastric emptying of solids (GES). Symptoms were assessed by the Gastroparesis Cardinal Symptom Index Daily Diary. After 4 weeks of treatment, we measured GES, gastric volumes, and Ensure (Abbott Laboratories, Abbott Park, IL) satiation test (1 kcal/mL, 30 mL/min) to assess volume to comfortable fullness and maximum tolerance. Patients underwent specific FAAH and CNR1 genotyping. Statistical analysis compared 2 treatments using analysis of variance including baseline measurements and body mass index as covariates.

RESULTS

Among 44 patients (32 idiopathic, 6 diabetes mellitus type 1, and 6 diabetes mellitus type 2), 5 patients did not tolerate full-dose escalation; 3 withdrew before completing 4 weeks of treatment (2 placebo, 1 CBD); 95% completed 4 weeks of treatment and diaries. Compared with placebo, CBD reduced the total Gastroparesis Cardinal Symptom Index score (P = .008), inability to finish a normal-sized meal (P = .029), number of vomiting episodes/24 hours (P = .006), and overall symptom severity (P = .034). Patients treated with CBD had a higher volume to comfortable fullness and maximum tolerance and slower GES. FAAH rs34420 genotype significantly impacted nutrient drink ingestion. The most common adverse events reported were diarrhea (14 patients), fatigue (8 patients), headache (8 patients), and nausea (7 patients).

CONCLUSIONS

CBD provides symptom relief in patients with gastroparesis and improves the tolerance of liquid nutrient intake, despite slowing of GES.

CLINICALTRIALS

gov NCT #03941288.

Relamorelin in Gastroparesis and Diabetic Gastroparesis: A Meta-Analysis on Its Efficacy and Safety

This meta-analysis aimed to evaluate the efficacy and safety of relamorelin, a synthetic ghrelin receptor agonist, for the treatment of gastroparesis and diabetic gastroparesis. A total of 1,033 participants from five randomized controlled trials were included. The primary outcome was the mean change in gastric emptying time from baseline. Relamorelin demonstrated a statistically significant improvement in gastric emptying time with a mean difference of -11.40 minutes compared to the placebo group. Furthermore, a significant improvement was observed specifically in diabetic gastroparesis patients, with a mean difference of -8.43 minutes. However, adverse effects, such as headaches, dizziness, and gastrointestinal symptoms, were more prevalent in the relamorelin group. Despite these adverse effects, the study concludes that relamorelin offers a promising avenue for gastroparesis treatment, especially given the limited existing therapeutic options. This comprehensive meta-analysis synthesizes existing evidence to inform clinical practice and guides future research in this domain.

Randomized clinical trial: A phase 2b controlled study of the efficacy and safety of trazpiroben (TAK-906) for idiopathic or diabetic gastroparesis

BACKGROUND

Previous clinical studies of trazpiroben, a dopamine D2 /D3 receptor antagonist for long-term treatment of moderate-to-severe idiopathic and diabetic gastroparesis, have shown improved symptoms of fullness. This study assessed trazpiroben efficacy, safety, and tolerability in adults with idiopathic and diabetic gastroparesis versus placebo.

METHODS

This global, multicenter, double-blind, parallel-group, phase 2b study (NCT03544229) enrolled eligible adults aged 18-85 years with symptomatic idiopathic or diabetic gastroparesis. Randomized participants received either oral placebo or trazpiroben 5, 25, or 50 mg, administered twice daily over 12 weeks, and completed the American Neurogastroenterology and Motility Society Gastroparesis Cardinal Symptom Index-Daily Diary. Change in weekly composite score from baseline to week 12 (primary endpoint) and treatment-emergent adverse events were assessed. Data were summarized descriptively.

KEY RESULTS

Overall, 242 participants were enrolled (mean [standard deviation] age 55.7 [14.2] years; 75.6% female); 193 completed the study. No significant differences in change from baseline in weekly average of the daily diary composite score occurred at week 12 between placebo (least-squares mean [standard error] -1.19 [0.12]) and trazpiroben (5, 25, and 50 mg: -1.11 [0.22], -1.17 [0.12], and -1.21 [0.12], respectively). Overall, 41.4% of participants receiving trazpiroben reported treatment-emergent adverse events (placebo, 39.7%). No serious events were considered trazpiroben-related; no life-threatening or fatal events were reported.

CONCLUSIONS & INFERENCES

There was no clinically meaningful difference in efficacy between trazpiroben and placebo in treating gastroparesis, based on the primary endpoint analysis. Trazpiroben was well tolerated with no new safety concerns identified, strengthening evidence supporting its favorable safety profile. NCT number: NCT03544229.

Diabetic Gastroparesis and its Emerging Therapeutic Options: A Narrative Review of the Literature

Diabetic gastroparesis (DG) is one of the many complications of diabetes mellitus (DM). Even though this condition surfaces years after uncontrolled disease, it affects the quality of life in several ways and causes significant morbidity. Common symptoms experienced by the patients include postprandial nausea, vomiting, abdominal fullness, and pain. Strict glycemic control is essential to evade the effects of DG. The purpose of this review article is to briefly study the pathophysiology, clinical features, diagnostic modalities, and the effects of DG on different aspects of life. Furthermore, it also focuses on the emerging treatment modalities for DG. Tradipitant and relamorelin are two such treatment options that are gaining noteworthy recognition and are discussed in detail in this review article. As observed through various clinical trials, these drugs help alleviate symptoms like nausea, vomiting, abdominal pain, and bloating in patients suffering from DG, thereby targeting the most common and bothersome symptoms of the disease. This leads to an improvement in the quality of life, making it a reliable treatment option for this disease. But while pharmacological intervention is vital, psychological support and lifestyle changes are equally important and are the reason why a multidisciplinary approach is required for the treatment of DG.

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.

Gastroparesis: Myths, Misconceptions, and Management

Gastroparesis (GP), a historically vexing disorder characterized by symptoms of nausea, vomiting, abdominal pain, early satiety, and/or bloating, in the setting of an objective delay in gastric emptying, is often difficult to treat and carries a tremendous burden on the quality of patients' lives, as well as the healthcare system in general. Though the etiology of GP has been fairly well defined, much work has been done recently to better understand the pathophysiology of GP, as well as to identify novel effective and safe treatment options. As our understanding of GP has evolved, many myths and misconceptions still abound in this rapidly changing field. The goal of this review is to identify myths and misconceptions regarding the etiology, pathophysiology, diagnosis, and treatment of GP, in the context of the latest research findings which have shaped our current understanding of GP. Recognition and dispelling of such myths and misconceptions is critical to moving the field forward and ultimately advancing the clinical management of what will hopefully become a better understood and more manageable disorder in the future.

A randomized, double-blind, placebo-controlled, phase 2b study of the efficacy and safety of velusetrag in subjects with diabetic or idiopathic gastroparesis

BACKGROUND

This study assessed the efficacy and safety of velusetrag-a 5-HT₄ agonist with pan-gastrointestinal prokinetic activity-for gastroparesis symptom management and gastric emptying (GE).

METHODS

In this multicenter, double-blind, randomized, placebo-controlled study, subjects with diabetic or idiopathic gastroparesis received velusetrag 5, 15, or 30 mg or placebo for 12 weeks. The primary efficacy outcome was a 7-day mean Gastroparesis Cardinal Symptom Index 24-h composite score (GCSI-24H) change from baseline at week 4; GE was evaluated using scintigraphy (GES) and breath tests, and safety from adverse events (AEs).

KEY RESULTS

232 subjects (183 females; 113 idiopathic gastroparesis) received treatment from February 2015 through June 2017. Least-squares mean improvement from baseline GCSI-24H (primary endpoint) at week 4 was -1.5 following velusetrag 5 mg vs -1.1 following placebo (treatment difference, -0.4; 95% confidence interval, -0.75 to -0.03; nominal p = 0.0327; Hochberg-adjusted p = 0.0980 [not significant]). Symptom improvement from baseline was achieved only with velusetrag 5 mg, which resulted in greater improvement from baseline vs placebo in all gastroparesis core symptoms, especially in subjects with idiopathic gastroparesis. Improvement from baseline GE by GES was greater in subjects receiving velusetrag (all doses) vs placebo; >70% of subjects receiving velusetrag 30 mg had GE normalization at 4 h. Treatment-emergent AEs were generally mild.

CONCLUSIONS AND INFERENCES

Velusetrag treatment was generally well-tolerated and associated with improved GE vs placebo in subjects with diabetic or idiopathic gastroparesis; however, only the lowest dose, velusetrag 5 mg, was associated with short-term improvement in gastroparesis symptoms.

CLINICALTRIALS

GOV: NCT02267525.

Efficacy and Safety of Drugs for Gastroparesis: Systematic Review and Network Meta-analysis

BACKGROUND & AIMS

Although there have been multiple drugs tested in gastroparesis, their relative efficacy and safety are unknown. We evaluated this in a network meta-analysis of randomized controlled trials (RCTs).

METHODS

We searched the literature to September 7, 2022. We judged the efficacy of drugs based on global symptoms of gastroparesis; individual symptoms, including nausea, vomiting, abdominal pain, bloating, or fullness; and safety according to total adverse events and adverse events leading to withdrawal. We extracted data as intention-to-treat analyses, assuming dropouts to be treatment failures and reporting pooled relative risks (RRs) of not improving with 95% confidence intervals (CIs), ranking drugs according to P-score.

RESULTS

We identified 29 RCTs (3772 patients). Based on global symptoms, clebopride ranked first for efficacy (RR, 0.30; 95% CI, 0.16-0.57; P-score = .99) followed by domperidone (RR, 0.68; 95% CI, 0.48-0.98; P-score = .76). No other drug was superior to placebo. Only 2 drug classes were efficacious: in rank order, oral dopamine antagonists (RR, 0.58; 95% CI, 0.44-0.77; P-score = .96) and tachykinin-1 antagonists (RR, 0.69; 95% CI, 0.52-0.93; P-score = .83). For individual symptoms, oral metoclopramide ranked first for nausea (RR 0.46; 95% CI, 0.21-1.00; P-score = .95), fullness (RR 0.67; 95% CI, 0.35-1.28; P-score = .86), and bloating (RR 0.53; 95% CI, 0.30-0.93; P-score = .97), based on only 1 small trial. Only prucalopride was more likely to be associated with adverse events than placebo.

CONCLUSIONS

In a network meta-analysis, oral dopamine antagonists and tachykinin-1 antagonists were more efficacious than placebo for gastroparesis, but confidence in the evidence was low to moderate for most comparisons. There is an unmet need for efficacious therapies for gastroparesis.

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.

Gastroparesis: An Evidence-Based Review for the Bariatric and Foregut Surgeon

Gastroparesis is a gastric motility disorder characterized by delayed gastric emptying. It is a rare disease and difficult to treat effectively; management is a dilemma for gastroenterologists and surgeons alike. We conducted a systematic review of the literature to evaluate current diagnostic tools as well as treatment options. We describe key elements in the pathophysiology of the disease, in addition to current evidence on treatment alternatives, including nutritional considerations, medical and surgical options, and related outcomes.

Do prokinetic agents provide symptom relief through acceleration of gastric emptying? An update and revision of the existing evidence

BACKGROUND

Gastroparesis and functional dyspepsia are disorders characterized by upper gastrointestinal symptoms and multifaceted etiologies. One of the main therapeutic approaches is accelerating gastric emptying (GE) by means of prokinetic agents. Their efficacy has been demonstrated, although the association between symptom improvement and acceleration of emptying is less clear. Meta-analyses have found contradictory results. Differences in applied methodology and included trials might drive these contradictions.

OBJECTIVE

To provide a transparent meta-analysis update to elucidate the association between symptom improvement and acceleration of GE due to gastroprokinetic agents available for long-term use in patients with gastroparesis.

DESIGN

Two approaches from earlier meta-analyses were executed and compared. One analyzed the relative changes on active treatment versus baseline, the other compared the change from baseline on active treatment versus the change from baseline on placebo. Papers that reported sufficient numerical data for both analyses were selected. Both analyses included the same trials.

RESULTS

Overall, both approaches yield the same positive direction of association between symptom improvement and acceleration of emptying (0.291 (-0.391, 0.972), p = 0.4 and 0.453 (0.123, 0.782), p = 0.007 for the active-only and placebo-controlled analysis respectively). The association between symptom improvement and GE acceleration for studies using optimal GE tests was either 0.028 (p > 0.9) or 0.463 (p = 0.007), and for sub-optimal GE tests was either 0.370 (p = 0.4) or 0.052 (p > 0.9) depending on the used meta-analysis methodology.

CONCLUSIONS

The applied methodology for GE testing, and the meta-analysis substantially impacts the conclusion. When considering the clinically relevant outcome of improvement from baseline, symptoms and emptying improve with prokinetics, but no correlation is found between both aspects. When the change over placebo is considered, limiting the analysis to scientifically more rigorous study approaches, changes in emptying rate and symptom improvement are positively associated.

Efficacy of prokinetic agents in diabetic gastroparesis comparing symptomatology and scintigraphy - An open-label trial

Background

It is pertinent to objectively assess the severity of diabetic gastroparesis and tailor treatment accordingly. The current study was planned to document gastroparesis by gastric emptying scintigraphy (GES) objectively and see the effect of medications and diet control on clinical and GES after four weeks.

Methods

A prospective, open-label randomized trial was conducted in the Department of Internal Medicine at a tertiary care teaching hospital over twelve months. Type 2 diabetic patients aged 18-65 years diagnosed with a case of delayed gastric emptying by gastric scintigraphy were included. All baseline GSCI was recorded, and then they were allotted to 3 groups - Group-1 (Levosulpiride 25mg once daily), group-2 (Cinitapride 1mg thrice daily), and Group-3 (Waitlisted control) by block randomization and followed-up weekly till four weeks. After four weeks duration, if not improved clinically, then Group-3 on diet and diabetic control only, were randomized into Levosulpiride 25mg once daily (Group 1), and Cinitapride 1mg Thrice daily (Group 2) for the next four weeks.

Results

Forty confirmed cases with diabetic gastroparesis documented by Gastroparesis Symptom Cardinal Index (GCSI) scoring and later by Scintigraphy (GES) were included in this study. However, there was no statistically significant difference between the Levosulpiride and Cinitapride groups when all symptoms were taken into account. Levosulpiride was significantly more effective than Cinitapride in improving individual symptoms like nausea, vomiting, stomach fullness, and early satiety.

Conclusion

Levosulpiride is better than Cinitapride in improving the symptoms of diabetic gastroparesis but no significant effect on gastric scintigraphy.

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.

Novel insights into the pathogenic impact of diabetes on the gastrointestinal tract

Type 2 and type 1 diabetes are common endocrine disorders with a progressively increasing incidence worldwide. These chronic, systemic diseases have multiorgan implications, and the whole gastrointestinal (GI) tract represents a frequent target in terms of symptom appearance and interdependent pathophysiological mechanisms. Metabolic alterations linked with diabetic complications, neuropathy and disrupted hormone homeostasis can lead to upper and/or lower GI symptoms in up to 75% of diabetic patients, with multifactorial involvement of the oesophagus, stomach, upper and lower intestine, and of the gallbladder. On the other hand, altered gastrointestinal motility and/or secretions are able to affect glucose and lipid homeostasis in the short and long term. Finally, diabetes has been linked with increased cancer risk at different levels of the GI tract. The presence of GI symptoms and a comprehensive assessment of GI function should be carefully considered in the management of diabetic patients to avoid further complications and to ameliorate the quality of life. Additionally, the presence of gastrointestinal dysfunction should be adequately managed to improve metabolic homeostasis, the efficacy of antidiabetic treatments and secondary prevention strategies.

Response and Adverse Event Rates With Placebo in Gastroparesis: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Multiple drugs have been used to treat gastroparesis symptoms, yet their therapeutic benefits are poorly understood partly due to lack of insight into response and adverse event rates with placebo in randomized controlled trials (RCTs). We evaluated these issues systematically in drug trials for gastroparesis.

METHODS

We searched the medical literature through August 2, 2022 to identify RCTs comparing active drug with placebo in patients with gastroparesis. We assessed placebo response rates according to at least one of the following endpoints: improvement according to a composite outcome, nausea, vomiting, abdominal pain, bloating, or fullness, as well as total adverse events, and adverse events leading to withdrawal. We extracted data as intention-to-treat analyses with dropouts assumed to be treatment failures. We pooled placebo response and adverse event rates using a random effects model and expressed as proportions with 95% confidence intervals (CIs).

RESULTS

Thirty-five studies were eligible. Among 23 trials reporting a composite endpoint of improvement, the pooled placebo response rate was 29.3% (95% CI, 23.7%-35.2%). Pooled placebo response rates were higher in idiopathic compared with diabetic gastroparesis (34.2% vs 28.1%), among trials that did not use validated symptom questionnaires (31.2% vs 27.4%), and in RCTs of shorter duration (<4 weeks, 32.6% vs ≥9 weeks, 23.2%). Adverse events occurred in 33.8% (95% CI, 26.4%-41.8%) of patients with placebo, in 27 trials, and were less common in idiopathic compared with diabetic gastroparesis (17.9% vs 43.4%), trials of shorter duration (<4 weeks, 33.7% vs ≥9 weeks, 40.7%), and trials with lower randomization ratios of active drug to placebo (1:1, 26.7% vs 3:1, 50.5%).

CONCLUSIONS

This meta-analysis assessed placebo response and adverse event rates in gastroparesis. To accurately assess therapeutic gain, future trials should be a minimum of 8 weeks duration, use validated questionnaires, and distinguish gastroparesis subtypes.

British Society of Gastroenterology guidelines on the management of functional dyspepsia

Functional dyspepsia (FD) is a common disorder of gut-brain interaction, affecting approximately 7% of individuals in the community, with most patients managed in primary care. The last British Society of Gastroenterology (BSG) guideline for the management of dyspepsia was published in 1996. In the interim, substantial advances have been made in understanding the complex pathophysiology of FD, and there has been a considerable amount of new evidence published concerning its diagnosis and classification, with the advent of the Rome IV criteria, and management. The primary aim of this guideline, commissioned by the BSG, is to review and summarise the current evidence to inform and guide clinical practice, by providing a practical framework for evidence-based diagnosis and treatment of patients. The approach to investigating the patient presenting with dyspepsia is discussed, and efficacy of drugs in FD summarised based on evidence derived from a comprehensive search of the medical literature, which was used to inform an update of a series of pairwise and network meta-analyses. Specific recommendations have been made according to the Grading of Recommendations Assessment, Development and Evaluation system. These provide both the strength of the recommendations and the overall quality of evidence. Finally, in this guideline, we consider novel treatments that are in development, as well as highlighting areas of unmet need and priorities for future research.

Poor Gastric Emptying in Patients with Paraesophageal Hernias: Pyloroplasty, Per-Oral Pyloromyotomy, BoTox, or Wait and See?

Gastric emptying delay may be caused with both functional and anatomic derangements. Gastroparesis is suspected in patients presenting with certain foregut symptoms without anatomic obstruction. Data are still emerging regarding the best treatment of this condition. In cases where large paraesophageal hernias alter the upper gastrointestinal anatomy, it is difficult to know if gastroparesis also exists. Management of hiatal hernias is also still evolving, with various strategies to reduce recurrence being actively investigated. In this article, we present a systematic review of the existing literature around the management of gastroparesis and the management of paraesophageal hernias when they occur separately. In addition, since there are limited data to guide diagnosis and management of these conditions when they are suspected to coexist, we provide a rational strategy based on our own experience in patients with paraesophageal hernias who have symptoms or studies that raise suspicion for a coexisting functional disorder.

ACG Clinical Guideline: Gastroparesis

Gastroparesis is characterized by symptoms suggesting retention of food in the stomach with objective evidence of delayed gastric emptying in the absence of mechanical obstruction in the gastric outflow. This condition is increasingly encountered in clinical practice. These guidelines summarize perspectives on the risk factors, diagnosis, and management of gastroparesis in adults (including dietary, pharmacological, device, and interventions directed at the pylorus), and they represent the official practice recommendations of the American College of Gastroenterology. The scientific evidence for these guidelines was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation process. When the evidence was not appropriate for Grading of Recommendations, Assessment, Development, and Evaluation, we used expert consensus to develop key concept statements. These guidelines should be considered as preferred but are not the only approaches to these conditions.

Gastrointestinal hormones and regulation of gastric emptying

PURPOSE OF REVIEW

In this review, we evaluate recent findings related to the association between gastrointestinal hormones and regulation of gastric emptying.

RECENT FINDINGS

Motilin and ghrelin, which act during fasting, promote gastric motility, whereas most of the hormones secreted after a meal inhibit gastric motility. Serotonin has different progastric or antigastric motility effects depending on the receptor subtype. Serotonin receptor agonists have been used clinically to treat dyspepsia symptoms but other hormone receptor agonists or antagonists are still under development. Glucagon-like peptide 1 agonists, which have gastric motility and appetite-suppressing effects are used as a treatment for obesity and diabetes.

SUMMARY

Gastrointestinal hormones play an important role in the regulation of gastric motility. Various drugs have been developed to treat delayed gastric emptying by targeting gastrointestinal hormones or their receptors but few have been commercialized.

AGA Clinical Practice Update on Management of Medically Refractory Gastroparesis: Expert Review

DESCRIPTION

Delayed gastric emptying on objective testing defines gastroparesis, but symptoms overlap with functional dyspepsia and do not correlate well with gastric emptying delay. This review outlines a strategy for defining, diagnosing, and managing refractory gastroparesis.

METHODS

The Best Practice Advice statements presented here were developed from review of existing literature combined with expert opinion to provide practical advice. Because this was not a systematic review, formal rating of the quality of evidence or strength of recommendations was not performed. BEST PRACTICE ADVICE.

Advances in the Development of Nonpeptide Small Molecules Targeting Ghrelin Receptor

Ghrelin is an octanoylated peptide acting by the activation of the growth hormone secretagogue receptor, namely, GHS-R1a. The involvement of ghrelin in several physiological processes, including stimulation of food intake, gastric emptying, body energy balance, glucose homeostasis, reduction of insulin secretion, and lipogenesis validates the considerable interest in GHS-R1a as a promising target for the treatment of numerous disorders. Over the years, several GHS-R1a ligands have been identified and some of them have been extensively studied in clinical trials. The recently resolved structures of GHS-R1a bound to ghrelin or potent ligands have provided useful information for the design of new GHS-R1a drugs. This perspective is focused on the development of recent nonpeptide small molecules acting as GHS-R1a agonists, antagonists, and inverse agonists, bearing classical or new molecular scaffolds, as well as on radiolabeled GHS-R1a ligands developed for imaging. Moreover, the pharmacological effects of the most studied ligands have been discussed.

Efficacy of Pro-Kinetic Agents in Type 2 Diabetes Mellitus Patients With Gastroparesis Using Lactulose Hydrogen Breath Testing: A Randomized Trial

Aim

The aim of the study was to determine the efficacy of prokinetic agents in diabetic gastroparesis patients.

Method

This was a randomized open-label trial conducted on 50 patients with type 2 diabetes experiencing diabetic gastroparesis, which was diagnosed with the lactulose hydrogen breath test. After randomization, all 50 patients were divided into four arms (cinitapride, metoclopramide, levosulpiride, and domperidone) of different prokinetics and followed up for four weeks; after which, repeat gastroparesis cardinal symptom index score and orocecal transit time were recorded in order to assess the response to the treatment.

Result

There was no statistically significant difference among the four groups in terms of all the baseline characteristics except for gender (p=0.032). The follow-up gastroparesis cardinal symptom index was collected for 50 patients but repeat orocecal transit time could be performed only in 37 patients. In all four groups, there was a statistically significant (p<0.05) improvement in terms of orocecal transit time and gastroparesis cardinal symptom index scores. But there was no statistically significant difference in relative efficacy amongst these study groups.

Conclusion

Our study showed statistically significant improvement with four prokinetics drugs in terms of gastroparesis cardinal symptom index score and orocecal transit time, but there was no statistically significant benefit of one prokinetic drug over the other. Our study showed promising results with regard to prokinetic use in diabetic gastroparesis.

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.

Relationship between symptoms during a gastric emptying study, daily symptoms and quality of life in patients with diabetes mellitus

AIMS

Gastric emptying is of limited utility for predicting the severity of symptoms in patients with diabetes mellitus and gastrointestinal symptoms. We evaluated the extent to which symptoms recorded during a ¹³ C-spirulina-based gastric emptying breath test (GEBT) or scintigraphy predicting the severity of daily symptoms in diabetes mellitus.

METHODS

Gastric emptying, symptoms during a gastric emptying study, either scintigraphy (n = 38) or GEBT (n = 111), and daily gastrointestinal symptoms were evaluated in 149 patients with diabetes mellitus and variably severe gastrointestinal symptoms.

KEY RESULTS

Gastric emptying was normal, delayed, and rapid in 37%, 52%, and 9% measured with the GEBT and 55%, 34%, and 11% of patients measured with scintigraphy; differences between GEBT and scintigraphy were not significant. Daily symptoms were moderately severe or more intense in 58% and 21% of patients undergoing scintigraphy and GEBT (P < 0.0001). Symptoms during the GEBT (46%) and emptying t_half (3%) explained 50% of the variance in daily symptoms in the GEBT group. In the scintigraphy group, symptoms explained 29% of this variance; the t_half was insignificant. Patients who reported that one or more symptoms were more severe than the others during the GE study were more likely (OR 3.98, 95% CI 2.16, 7.33) to report the same symptom(s) as being the most severe in the daily diary.

CONCLUSIONS

Symptoms during a GEBT and to a lesser extent during scintigraphy, but not gastric emptying predict the severity of daily symptoms and may serve as a biomarker in patients with diabetes mellitus.

Management of Gastroparesis

Gastroparesis is a gastrointestinal motility disorder characterized by nausea, vomiting, early satiation, postprandial fullness, bloating, and upper abdominal pain. The diagnosis requires documented delay in gastric emptying with an optimal test such as scintigraphy or stable isotope gastric emptying breath test in the absence of mechanical obstruction. The pathophysiologic mechanisms of gastroparesis are multifactorial, including antroduodenal hypomotility, pylorospasm, impaired gastric accommodation, and visceral hypersensitivity. The etiologies of gastroparesis are broad, but the most common subtypes are idiopathic, diabetic, and postsurgical. Less frequent etiologies are neurodegenerative disorder (Parkinson disease), myopathies (scleroderma, amyloidosis), and neoplastic syndrome. Symptoms of gastroparesis can be refractory and challenging to manage, leading to reduced quality of life and significant health care expenditure. This article introduces the epidemiology, clinical presentation, diagnosis, and differential diagnoses of gastroparesis, followed by a focused discussion on its management, including nutritional support, prokinetic and antiemetic agents, and emerging interventions directed at the pylorus. Robust sham-controlled trials are needed to evaluate the long-term efficacy of gastric peroral endoscopic myotomy. A multidisciplinary approach with individualized strategies based on characterization of the patho-physiology is deemed necessary to enhance clinical outcomes.

Hirschsprung disease and Paediatric Intestinal Pseudo-obstruction

Hirschsprung disease (HSCR) and Paediatric Intestinal Pseudo-obstruction (PIPO) comprise two of the most recognized and severe disorders of gastrointestinal (GI) motility. HSCR is a developmental disorder of the enteric nervous system invariably affecting the large intestine, whereas the majority of PIPO conditions represent congenital disorders of one or more components of the neuromusculature and more diffusely affect the GI tract. Histopathology is deemed the gold standard for the diagnosis of HSCR and, arguably, of PIPO, but, other diagnostic modalities such as manometric and genetic studies have seen recent advances that may increase their utility. Especially for PIPO, management is multidisciplinary and best performed in specialist referral centres. Surgery remains the only viable treatment for HSCR and appears essential to optimize and sustain feeding and viability of intestinal function in PIPO patients. Novel therapies such as neural stem cell transplants show promise for the future.

New Developments in Prokinetic Therapy for Gastric Motility Disorders

Prokinetic agents amplify and coordinate the gastrointestinal muscular contractions to facilitate the transit of intra-luminal content. Following the institution of dietary recommendations, prokinetics are the first medications whose goal is to improve gastric emptying and relieve symptoms of gastroparesis. The recommended use of metoclopramide, the only currently approved medication for gastroparesis in the United States, is for a duration of less than 3 months, due to the risk of reversible or irreversible extrapyramidal tremors. Domperidone, a dopamine D2 receptor antagonist, is available for prescription through the FDA's program for Expanded Access to Investigational Drugs. Macrolides are used off label and are associated with tachyphylaxis and variable duration of efficacy. Aprepitant relieves some symptoms of gastroparesis. There are newer agents in the pipeline targeting diverse gastric (fundic, antral and pyloric) motor functions, including novel serotonergic 5-HT4 agonists, dopaminergic D2/3 antagonists, neurokinin NK1 antagonists, and ghrelin agonist. Novel targets with potential to improve gastric motor functions include the pylorus, macrophage/inflammatory function, oxidative stress, and neurogenesis. In the current review, we discuss the use of pharmacological approaches with potential to enhance motor functions in the management of gastroparesis.

The mechanism of esophagus dysmotility in diabetes and research progress of relating treatments

Introduction: Esophagus dysmotility is a crucial risk factor of gastroesophageal reflux disease (GERD), which is one of the most common diseases in digestive medicine globally. This review emphasizes the mechanisms of esophagus dysmotility in diabetes and summarizes more targeted treatments for these patients to avoid the overuse of proton pump inhibitors (PPIs).Areas covered: Diabetes mellitus (DM) is a clear factor that must not be neglected in the development of GERD. Previous studies have preliminarily researched the esophagus deterioration in diabetes. However, the multi-faceted mechanisms of esophagus dysmotility in diabetes need more studies. Besides, targeted treatments for these patients rather than conventional PPIs are urgently needed.Expert opinion: The treatments for GERD patients with diabetes should be further explored. Pharmacological approaches such as prokinetic agents, psychotherapy can be adopted. Meanwhile, it's feasible to explore non-drug treatments. For example, Electroacupuncture (EA) at Zusanli (ST-36) may be effective to protect the networks of intestinal cells of Cajal (ICCs) in diabetes. More effective approaches should be explored to achieve individualized treatment for these patients.

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.

MALAT1: A Pivotal lncRNA in the Phenotypic Switch of Gastric Smooth Muscle Cells via the Targeting of the miR-449a/DLL1 Axis in Diabetic Gastroparesis

Diabetic gastroparesis (DGP) is a common complication of diabetes mellitus (DM). Our previous study suggested that the expression of the long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is closely related to DGP. However, the role of MALAT1 in DGP pathogenesis remains unclear. Here, we aim to characterize the role of MALAT1 in DGP. First, we analyzed the lncRNA expression profiles through lncRNA sequencing. Next, we detected MALAT1 expression in the stomach tissues of DGP model mice and diabetic patients. Then, we investigated the role and mechanisms of MALAT1 in the proliferation, migration, phenotypic switch, and carbachol-induced intracellular Ca²⁺ changes in human gastric smooth muscle cells (HGSMCs) under high glucose (HG) conditions, using short hairpin RNA technology, RNA immunoprecipitation, and dual-luciferase reporter assays. We show that MALAT1 expression was upregulated in the gastric tissues of DGP model mice, the adjacent healthy tissues collected from diabetic gastric cancer patients with DGP symptoms, and in HGSMCs cultured under HG conditions. Functionally, MALAT1 knockdown in vitro impacted the viability, proliferation, migration and promoted the phenotypic switch of HGSMCs under HG conditions. Additionally, we show that MALAT1 sponged miR-449a, regulating Delta-like ligand 1 (DLL1) expression in HGSMCs; any disturbance of the MALAT1/miR-449a/DLL1 pathway affects the proliferation, migration, phenotypic switch, and carbachol-induced Ca²⁺ transient signals in HGSMCs under HG conditions. Collectively, our data highlight a novel regulatory signaling pathway, the MALAT1/miR-449a/DLL1 axis, in the context of DGP.

Gastroparesis in Parkinson Disease: Pathophysiology, and Clinical Management

Patients with Parkinson disease (PD) experience a range of non-motor symptoms, including gastrointestinal symptoms. These symptoms can be present in the prodromal phase of the disease. Recent advances in pathophysiology reveal that α-synuclein aggregates that form Lewy bodies and neurites, the hallmark of PD, are present in the enteric nervous system and may precede motor symptoms. Gastroparesis is one of the gastrointestinal involvements of PD and is characterized by delayed gastric emptying of solid food in the absence of mechanical obstruction. Gastroparesis has been reported in nearly 45% of PD. The cardinal symptoms include early satiety, postprandial fullness, nausea, and vomiting. The diagnosis requires an appropriate test to confirm delayed gastric emptying, such as gastric scintigraphy, or breath test. Gastroparesis can lead to malnutrition and impairment of quality of life. Moreover, it might interfere with the absorption of antiparkinsonian drugs. The treatment includes dietary modifications, and pharmacologic agents both to accelerate gastric emptying and relieve symptoms. Alternative treatments have been recently developed in the management of gastroparesis, and their use in patients with PD will be reported in this review.

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

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

One-year results of gastric peroral endoscopic myotomy for refractory gastroparesis: a French multicenter study

BACKGROUND

Data on the long-term outcomes of gastric peroral endoscopic myotomy (G-POEM) for refractory gastroparesis are lacking. We report the results of a large multicenter long-term follow-up study of G-POEM for refractory gastroparesis.

METHODS

This was a retrospective multicenter study of all G-POEM operations performed in seven expert French centers for refractory gastroparesis with at least 1 year of follow-up. The primary endpoint was the 1-year clinical success rate, defined as at least a 1-point improvement in the Gastroparesis Cardinal Symptom Index (GCSI).

RESULTS

76 patients were included (60.5 % women; age 56 years). The median symptom duration was 48 months. The median gastric retention at 4 hours (H4) before G-POEM was 45 % (interquartile range [IQR] 29 % - 67 %). The median GCSI before G-POEM was 3.6 (IQR 2.8 - 4.0). Clinical success was achieved in 65.8 % of the patients at 1 year, with a median rate of reduction in the GCSI score of 41 %. In logistic regression analysis, only a high preoperative GCSI satiety subscale score was predictive of clinical success (odds ratio [OR] 3.41, 95 % confidence interval [CI] 1.01 - 11.54; P = 0.048), while a high rate of gastric retention at H4 was significantly associated with clinical failure (OR 0.97, 95 %CI 0.95 - 1.00; P = 0.03).

CONCLUSIONS

The results confirm the efficacy of G-POEM for the treatment of refractory gastroparesis, as evidenced by a 65.8 % clinical success rate at 1 year. Although G-POEM is promising, prospective sham-controlled trials are urgently needed to confirm its efficacy and identify the patient populations who will benefit most from this procedure.

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.

Gastric Sensory and Motor Functions and Energy Intake in Health and Obesity-Therapeutic Implications

Sensory and motor functions of the stomach, including gastric emptying and accommodation, have significant effects on energy consumption and appetite. Obesity is characterized by energy imbalance; altered gastric functions, such as rapid gastric emptying and large fasting gastric volume in obesity, may result in increased food intake prior to reaching usual fullness and increased appetite. Thus, many different interventions for obesity, including different diets, anti-obesity medications, bariatric endoscopy, and surgery, alter gastric functions and gastrointestinal motility. In this review, we focus on the role of the gastric and intestinal functions in food intake, pathophysiology of obesity, and obesity management.

Nausea and Vomiting in 2021: A Comprehensive Update

GOAL

A comprehensive review of treatments for nausea and vomiting (N/V).

BACKGROUND

N/V are common symptoms encountered in medicine. While most cases of acute N/V related to a specific cause can be straightforward to manage, other cases of acute N/V such as chemotherapy-induced N/V and especially chronic unexplained N/V can be difficult to control, leading to a significant decline in the patient's quality of life and increased cost of medical care from repeated hospitalizations.

STUDY

Traditional management has relied on pharmacotherapy which may be inadequate in a certain proportion of these patients. Many of the medications used in the management of N/V have significant side effect profiles making the need for new and improved interventions of great importance.

RESULTS

This review covers a broad review of the pathophysiology of N/V, pharmacotherapy, including safety concerns and controversies with established pharmaceuticals, newer immunotherapies, bioelectrical neuromodulation (including gastric electrical stimulation), behavioral and surgical therapies, and complementary medicine.

CONCLUSION

On the basis of emerging understandings of the pathophysiology of N/V, improved therapies are becoming available.

Recent Advances in the Definition and Management of Functional Dyspepsia

In 2016, the Rome criteria were updated as Rome IV, and only minor changes were introduced for functional dyspepsia (FD). The major symptoms of FD now include not only postprandial fullness, but also epigastric pain and burning, and early satiation at above the "bothersome" level. Investigations into the effect of meal ingestion on symptom generation have indicated that not only postprandial fullness and early satiety but also epigastric pain and burning sensation and nausea (not vomiting) may increase after meals. Helicobacter pylori infection is considered to be the cause of dyspepsia if successful eradication leads to sustained resolution of symptoms for more than 6 months, and such a condition has been termed H. pylori-associated dyspepsia. Prompt esophagogastroduodenoscopy and H. pylori "test and treat" may be beneficial, especially in regions with a high prevalence of gastric cancer, such as east Asia. In terms of treatment, acotiamide, tandospirone, and rikkunshito are newly listed in Rome IV as treatment options for FD. Clinical studies in the field of FD should be strictly based on the Rome IV criteria until the next Rome V is published in 2026.

Management of Dyspepsia and Gastroparesis in Patients with Diabetes. A Clinical Point of View in the Year 2021

Diabetes mellitus is a widespread disease, and represents an important public health burden worldwide. Together with cardiovascular, renal and neurological complications, many patients with diabetes present with gastrointestinal symptoms, which configure the so-called diabetic enteropathy. In this review, we will focus on upper gastrointestinal symptoms in patients with diabetes, with particular attention to dyspepsia and diabetic gastroparesis (DG). These two clinical entities share similar pathogenetic mechanisms, which include autonomic neuropathy, alterations in enteric nervous system and histological abnormalities, such as interstitial cells of Cajal depletion. Moreover, the differential diagnosis may be challenging because of overlapping clinical features. Delayed gastric emptying should be documented to differentiate between DG and dyspepsia and it can be assessed through radioactive or non-radioactive methods. The clinical management of dyspepsia includes a wide range of different approaches, above all Helicobacter pylori test and treat. As regards DG treatment, a central role is played by dietary modification and glucose control and the first-line pharmacological therapy is represented by the use of prokinetics. A minority of patients with DG refractory to medical treatment may require more invasive therapeutic approaches, including supplemental nutrition, gastric electric stimulation, pyloromyotomy and gastrectomy.

Direct optogenetic stimulation of smooth muscle cells to control gastric contractility

Rationale: Antral peristalsis is responsible for gastric emptying. Its failure is called gastroparesis and often caused by dysfunction of enteric neurons and interstitial cells of Cajal (ICC). Current treatment options, including gastric electrical stimulation, are non-satisfying and may improve symptoms but commonly fail to restore gastric emptying. Herein, we explore direct optogenetic stimulation of smooth muscle cells (SMC) via the light-gated non-selective cation channel Channelrhodopsin2 (ChR2) to control gastric motor function.

Methods: We used a transgenic mouse model expressing ChR2 in fusion with eYFP under the control of the chicken-β-actin promoter. We performed patch clamp experiments to quantify light-induced currents in isolated SMC, Ca²⁺ imaging and isometric force measurements of antral smooth muscle strips as well as pressure recordings of intact stomachs to evaluate contractile responses. Light-induced propulsion of gastric contents from the isolated stomach preparation was quantified in video recordings. We furthermore tested optogenetic stimulation in a gastroparesis model induced by neuronal- and ICC-specific damage through methylene blue photo-toxicity.

Results: In the stomachs, eYFP signals were restricted to SMC in which blue light (460 nm) induced inward currents typical for ChR2. These depolarizing currents led to contractions in antral smooth muscle strips that were stronger than those triggered by supramaximal electrical field stimulation and comparable to those evoked by global depolarization with high K⁺ concentration. In the intact stomach, panoramic illumination efficiently increased intragastric pressure achieving 239±46% (n=6) of the pressure induced by electrical field stimulation and triggered gastric transport. Within the gastroparesis model, electric field stimulation completely failed but light still efficiently generated pressure waves.

Conclusions: We demonstrate direct optogenetic stimulation of SMC to control gastric contractility. This completely new approach could allow for the restoration of motility in gastroparesis in the future.