Clinical trial: effect of mitemcinal (a motilin agonist) on gastric emptying in patients with gastroparesis - a randomized, multicentre, placebo-controlled study

Effects of ondansetron on symptoms during a gastric emptying study and enteral lipid challenge and on daily symptoms in diabetic gastroenteropathy

BACKGROUND

This study compared the effects of ondansetron and placebo in patients with diabetes mellitus and symptoms of dyspepsia (diabetic gastroenteropathy [DGE]).

METHODS

We performed a randomized, double-blinded, placebo-controlled study of ondansetron tablets (8 mg) three times daily for 4 weeks in DGE patients. Symptoms were assessed with the Gastroparesis Cardinal Symptom Index daily diaries. Gastric emptying (GE) of solids (scintigraphy) and duodenal lipid infusions (300 kcal over 2 h) were each assessed twice, with placebo and ondansetron. Drug effects on GE, symptoms during the GE study and during lipid infusion, and daily symptoms were analyzed.

KEY RESULTS

Of 41 patients, 37 completed both GE studies and one completed 1; 31 completed both lipid infusions and four only placebo; and all 35 randomized patients completed 4 weeks of treatment. Compared to placebo, ondansetron reduced the severity of fullness (p = 0.02) and belching (p = 0.049) during lipid infusion but did not affect GE T1/2. Both ondansetron and placebo improved daily symptoms versus the baseline period (p < 0.05), but the differences were not significant. In the analysis of covariance of daily symptoms during the treatment period, the interaction term between treatment and the acute effect of ondansetron on symptoms during lipid challenge was significant (p = .024).

CONCLUSIONS & INFERENCES

Ondansetron significantly reduced fullness during enteral lipid infusion in patients with DGE. Overall, ondansetron did not improve daily symptoms versus placebo. But patients in whom ondansetron improved symptoms during enteral lipid challenge were perhaps more likely to experience symptom relief during daily treatment.

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.

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.

Multimodal Approaches in the Treatment of Chronic Peripheral Neuropathy-Evidence from Germany

Patients with chronic peripheral neuropathy suffer greatly and their quality of life is often restricted. Drug therapy can be accompanied by undesirable side effects and intolerances, or the hoped-for effect does not materialize. Therefore, in addition to drug therapy, attempts are also made to treat the physical symptoms with complementary procedures. In the case of severe forms, the search for a suitable form of therapy is difficult. Complex treatments can be an innovative way to treat peripheral neuropathy. At the same time, several different therapy methods are carried out at high frequency by a specialized treatment team. This study aimed to provide an overview of possible complementary forms of therapy. The focus was on a comparison of two interdisciplinary complex therapies that are used in severe cases in an acute inpatient care setting in Germany. The six dimensions (energy, sleep, pain, physicality, emotional response and social isolation) of the Nottingham Health Profile (NHP) were used to assess quality of life. Both complex treatments (naturopathic complex therapy/multimodal pain therapy) showed a significant reduction in impairment in all dimensions of the NHP. In addition, a multivariate analysis was carried out to take into account several influencing variables at the same time. At the time of admission to the hospital, the degree of chronicity was recorded for each patient. This allowed statements to be made about the effect of the respective therapy depending on the chronification stage of the patient. It has been shown that patients with acutely exacerbated pain with the highest degree of chronicity also benefit from both complex treatments. The naturopathic complex treatment gives the treatment team more options. Aspects such as nutrition, methods from phytotherapy and traditional Chinese medicine can be integrated into inpatient care. Thus, a patient-centered, holistic therapy can take place. However, an interdisciplinary holistic therapy requires more time for both the practitioner and the patient. This should be taken into account in the health systems in the context of the diagnosis related groups.

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.

Physiological functions and potential clinical applications of motilin

Motilin is a gastrointestinal hormone secreted by the duodenum. This peptide regulates a characteristic gastrointestinal contraction pattern, called the migrating motor complex, during the fasting state. Motilin also affects the pressure of the lower esophageal sphincter, gastric motility and gastric accommodation in the gastrointestinal tract. Furthermore, motilin induces bile discharge into the duodenum by promoting gallbladder contraction, pepsin secretion in the stomach, pancreatic juice and insulin secretion from the pancreas. In recent years, it has been shown that motilin is associated with appetite, and clinical applications are expected for diseases affected by food intake, e.g. obesity, by regulating motilin levels. Gastric acid and bile are the two major physiological regulators for motilin release. Caloric foods have varying effects on motilin levels, depending on their composition. Among non-caloric foods, bitter substances reduce motilin levels and are therefore expected to have an appetite-suppressing effect. Various motilin receptor agonists and antagonists have been developed but have yet to reach clinical use.

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.

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.

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.

Robust Methods to Detect Abnormal Initiation in the Gastric Slow Wave from Cutaneous Recordings

Upper gastrointestinal (GI) disorders are highly prevalent, with gastroparesis (GP) and functional dyspepsia (FD) affecting 3% and 10% of the US population, respectively. Despite overlapping symptoms, differing etiologies of GP and FD have distinct optimal treatments, thus making their management a challenge. One such cause, that of gastric slow wave abnormalities, affects the electromechanical coordination of pacemaker cells and smooth muscle cells in propelling food through the GI tract. Abnormalities in gastric slow wave initiation location and propagation patterns can be treated with novel pacing technologies but are challenging to identify with traditional spectral analyses from cutaneous recordings due to their occurrence at the normal slow wave frequency. This work advances our previous work in developing a 3D convolutional neural network to process multi-electrode cutaneous recordings and successfully classify, in silico, normal versus abnormal slow wave location and propagation patterns. Here, we use transfer learning to build a method that is robust to heterogeneity in both the location of the abnormal initiation on the stomach surface as well as the recording start times with respect to slow wave cycles. We find that by starting with training lowest-complexity models and building complexity in training sets, transfer learning one model to the next, the final network exhibits, on average, 80% classification accuracy in all but the most challenging spatial abnormality location, and below 5% Type-I error probabilities across all locations.

Ghrelin inhibits autonomic response to gastric distension in rats by acting on vagal pathway

Ghrelin is the only orexigenic peptide currently known and a potent prokinetic by promoting gastric motility but novel insights suggest that its role extends beyond satiety regulation. Whereas ghrelin was shown to provide somatic and colonic antinociception, its impact on gastric sensitivity is unknown even though stomach is a major ghrelin secreting tissue. Autonomic response to gastric mechanosensitivity was estimated by measuring blood pressure variation as a surrogate marker in response to gastric distension (GD) before and after ghrelin (or vehicle) administration. Involvement of spinal and vagal pathways in the ghrelin effect was studied by performing celiac ganglionectomy and subdiaphragmatic vagotomy respectively and by evaluating the expression of phosphorylated extracellular-regulated kinase 1/2 (p-ERK1/2) in dorsal root and nodose ganglia. Finally the phenotype of Ghrelin receptor expressing neurons within the nodose ganglia was determined by in situ hybridization and immunofluorescence. Ghrelin reduced blood pressure variation in response to GD except in vagotomized rats. Phosphorylated-ERK1/2 levels indicated that ghrelin reduced neuronal activation induced by GD in nodose ganglion. The effect of ghrelin on gastric mechanosensitivity was abolished by pre-treatment with antagonist [D-Lys³]-GHRP-6 (0.3 mg/kg i.v.). Immunofluorescence staining highlights the colocalization of Ghrelin receptor with ASIC3 and TRPV1 within gastric neurons of nodose ganglion. Ghrelin administration reduced autonomic response to gastric distension. This effect likely involved the Ghrelin receptor and vagal pathways.

The Role of GI Peptides in Functional Dyspepsia and Gastroparesis: A Systematic Review

Functional dyspepsia (FD) and gastroparesis (GP) are common disorders of the upper gastrointestinal tract. The pathophysiology of these conditions is likely to be heterogenous, and factors such as altered motility, sensitivity and response to nutrition have been identified as putative underlying mechanisms. Motility, sensitivity as well as responses to nutrition can be influenced or mediated by peptide hormones and serotonin released from the gastrointestinal mucosa. This review summarizes the role of GI peptides in functional dyspepsia and gastroparesis. In most studies, the levels of somatostatin, ghrelin, and motilin did not differ between healthy volunteers and FD or GP patients, but higher symptom burden was often correlated with higher peptide levels. Ghrelin and motilin receptor agonists showed promising results in improvement of the gastric emptying, but the link with improvement of symptoms is less predictable. Serotonin agonists have a potential to improve symptoms in both FD and idiopathic gastroparesis. Drugs acting on the GLP-1 and on the PYY receptors deserve further investigation. There is a need for systematic large scale studies.

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.

Diabetic Gastroparesis and Glycaemic Control

PURPOSE OF REVIEW

Gastroparesis is an important complication of diabetes that may have a major impact on the quality of life as a result of upper gastrointestinal symptoms and impaired glycaemic control. Current management strategies include optimising blood glucose control, dietary modifications and supportive nutrition. Pharmacologic approaches with drugs that have prokinetic and/or antiemetic effects are also used widely; however, current available treatments have major limitations. There is increasing recognition that the rate of gastric emptying (GE) is a key determinant of the glycaemic response to a meal.

RECENT FINDINGS

There is ongoing uncertainty regarding the impact of longstanding hyperglycaemia on GE, which requires clarification. New diagnostic techniques have been developed to better characterise the mechanisms underlying gastroparesis in individual patients, and these have the potential to lead to more personalised therapy. Management of gastroparesis is complex and suboptimal; novel approaches are desirable. This review summarises recent advances in the understanding of diabetic gastroparesis, with an emphasis on the current therapies that influence GE, and the bidirectional relationship between glycaemic control and GE.

Spatial Patterns From High-Resolution Electrogastrography Correlate With Severity of Symptoms in Patients With Functional Dyspepsia and Gastroparesis

BACKGROUND & AIMS

Invasive gastric electrical mapping has revealed spatial abnormalities of the slow wave in subjects with gastroparesis and functional gastrointestinal disorders. Cutaneous high-resolution electrogastrography (HR-EGG) is a non-invasive method that can detect spatial features of the gastric slow wave. We performed HR-EGG in subjects with active foregut symptoms to evaluate associations between gastric myoelectric abnormalities, symptoms (based on a validated questionnaire), and gastric emptying.

METHODS

We performed a case-control study of 32 subjects, including 7 healthy individuals (controls), 7 subjects with functional dyspepsia and normal gastric emptying, and 18 subjects with gastroparesis, from a tertiary care program. All subjects were assessed by computed tomography imaging of the abdomen and HR-EGG and completed the PAGI-SYM questionnaire on foregut symptoms, which includes the gastroparesis cardinal symptom index. We performed volume reconstruction of the torso and stomach from computed tomography images to guide accurate placement of the HR-EGG array.

RESULTS

Spatial slow-wave abnormalities were detected in 44% of subjects with foregut symptoms. Moreover, subjects with a higher percentage of slow waves with aberrant propagation direction had a higher total gastroparesis cardinal symptom index score (r = 0.56; P < .001) and more severe abdominal pain (r = 0.46; P = .009). We found no correlation between symptoms and traditional EGG parameters.

CONCLUSIONS

In case-control study, we found that the genesis of symptoms of functional dyspepsia and gastroparesis is likely multifactorial, including possible contribution from gastric myoelectric dysfunction. Abnormal spatial parameters, detected by cutaneous HR-EGG, correlated with severity of upper gastrointestinal symptoms, regardless of gastric emptying. This noninvasive, repeatable approach might be used to identify patients for whom gastric myoelectric dysfunction contributes to functional dyspepsia and gastroparesis.

Bayesian inverse methods for spatiotemporal characterization of gastric electrical activity from cutaneous multi-electrode recordings

Gastrointestinal (GI) problems give rise to 10 percent of initial patient visits to their physician. Although blockages and infections are easy to diagnose, more than half of GI disorders involve abnormal functioning of the GI tract, where diagnosis entails subjective symptom-based questionnaires or objective but invasive, intermittent procedures in specialized centers. Although common procedures capture motor aspects of gastric function, which do not correlate with symptoms or treatment response, recent findings with invasive electrical recordings show that spatiotemporal patterns of the gastric slow wave are associated with diagnosis, symptoms, and treatment response. We here consider developing non-invasive approaches to extract this information. Using CT scans from human subjects, we simulate normative and disordered gastric surface electrical activity along with associated abdominal activity. We employ Bayesian inference to solve the ill-posed inverse problem of estimating gastric surface activity from cutaneous recordings. We utilize a prior distribution on the spatiotemporal activity pertaining to sparsity in the number of wavefronts on the stomach surface, and smooth evolution of these wavefronts across time. We implement an efficient procedure to construct the Bayes optimal estimate and demonstrate its superiority compared to other commonly used inverse methods, for both normal and disordered gastric activity. Region-specific wave direction information is calculated and consistent with the simulated normative and disordered cases. We apply these methods to cutaneous multi-electrode recordings of two human subjects with the same clinical description of motor function, but different diagnosis of underlying cause. Our method finds statistically significant wave propagation in all stomach regions for both subjects, anterograde activity throughout for the subject with diabetic gastroparesis, and retrograde activity in some regions for the subject with idiopathic gastroparesis. These findings provide a further step towards towards non-invasive phenotyping of gastric function and indicate the long-term potential for enabling population health opportunities with objective GI assessment.

Diabetic Gastroparesis

This review covers the epidemiology, pathophysiology, clinical features, diagnosis, and management of diabetic gastroparesis, and more broadly diabetic gastroenteropathy, which encompasses all the gastrointestinal manifestations of diabetes mellitus. Up to 50% of patients with type 1 and type 2 DM and suboptimal glycemic control have delayed gastric emptying (GE), which can be documented with scintigraphy, 13C breath tests, or a wireless motility capsule; the remainder have normal or rapid GE. Many patients with delayed GE are asymptomatic; others have dyspepsia (i.e., mild to moderate indigestion, with or without a mild delay in GE) or gastroparesis, which is a syndrome characterized by moderate to severe upper gastrointestinal symptoms and delayed GE that suggest, but are not accompanied by, gastric outlet obstruction. Gastroparesis can markedly impair quality of life, and up to 50% of patients have significant anxiety and/or depression. Often the distinction between dyspepsia and gastroparesis is based on clinical judgement rather than established criteria. Hyperglycemia, autonomic neuropathy, and enteric neuromuscular inflammation and injury are implicated in the pathogenesis of delayed GE. Alternatively, there are limited data to suggest that delayed GE may affect glycemic control. The management of diabetic gastroparesis is guided by the severity of symptoms, the magnitude of delayed GE, and the nutritional status. Initial options include dietary modifications, supplemental oral nutrition, and antiemetic and prokinetic medications. Patients with more severe symptoms may require a venting gastrostomy or jejunostomy and/or gastric electrical stimulation. Promising newer therapeutic approaches include ghrelin receptor agonists and selective 5-hydroxytryptamine receptor agonists.

Metoclopramide for the treatment of diabetic gastroparesis

Introduction: Gastroparesis is a chronic disorder of the stomach characterized by delayed gastric emptying without mechanical obstruction. Diabetes is the most commonly known cause of gastroparesis. Management of diabetic gastroparesis involves lifestyle modifications, glycemic control, pharmacological drugs, and for refractory cases surgical treatments. Metoclopramide remains the only drug approved by the Food and Drug Administration for diabetic gastroparesis. The aim of this article is to provide a concise review of the pharmacology, clinical efficacy and tolerability of metoclopramide. Areas covered: We searched PubMed using the key words 'metoclopramide', 'diabetic gastroparesis', and 'gastric emptying'. The relevant articles and their bibliography were reviewed. Metoclopramide acts on several different receptors; primarily as a dopamine receptor antagonist, both peripherally improving gastric emptying, and centrally resulting in an anti-emetic effect. Metoclopramide side effects, mostly related to its ability to cross the blood-brain barrier, include drowsiness, restlessness, hyperprolactinemia, and tardive dyskinesia (TD), a movement disorder that may be irreversible. Expert opinion: Metoclopramide carries a black box warning for use >12 weeks due to the risk of TD. However, gastroparesis patients experience chronic symptoms often requiring prolonged treatments. Physicians and patients look forward to FDA approval of new agents for gastroparesis with better efficacy and safety profile.

A Deep Convolutional Neural Network Approach to Classify Normal and Abnormal Gastric Slow Wave Initiation From the High Resolution Electrogastrogram

OBJECTIVE

Gastric slow wave abnormalities have been associated with gastric motility disorders. Invasive studies in humans have described normal and abnormal propagation of the slow wave. This study aims to disambiguate the abnormally functioning wave from one of normalcy using multi-electrode abdominal waveforms of the electrogastrogram (EGG).

METHODS

Human stomach and abdominal models are extracted from computed tomography scans. Normal and abnormal slow waves are simulated along stomach surfaces. Current dipoles at the stomachs surface are propagated to virtual electrodes on the abdomen with a forward model. We establish a deep convolutional neural network (CNN) framework to classify normal and abnormal slow waves from the multi-electrode waveforms. We investigate the effects of non-idealized measurements on performance, including shifted electrode array positioning, smaller array sizes, high body mass index (BMI), and low signal-to-noise ratio (SNR). We compare the performance of our deep CNN to a linear discriminant classifier using wave propagation spatial features.

RESULTS

A deep CNN framework demonstrated robust classification, with accuracy above 90% for all SNR above 0 dB, horizontal shifts within 3 cm, vertical shifts within 6 cm, and abdominal tissue depth within 6 cm. The linear discriminant classifier was much more vulnerable to SNR, electrode placement, and BMI.

CONCLUSION

This is the first study to attempt and, moreover, succeed in using a deep CNN to disambiguate normal and abnormal gastric slow wave patterns from high-resolution EGG data.

SIGNIFICANCE

These findings suggest that multi-electrode cutaneous abdominal recordings have the potential to serve as widely deployable clinical screening tools for gastrointestinal foregut disorders.

Role of Gut Microbiota-Gut Hormone Axis in the Pathophysiology of Functional Gastrointestinal Disorders

Gut microbiota exert a pivotal influence on various functions including gastrointestinal (GI) motility, metabolism, nutrition, immunity, and the neuroendocrine system in the host. These effects are mediated by not only short-chain fatty acids produced by microbiota but also gut hormones and inflammatory signaling by enteroendocrine and immune cells under the influence of the microbiota. GI motility is orchestrated by the enteric nervous system and hormonal networks, and disturbance of GI motility plays an important role in the pathophysiology of functional gastrointestinal disorders (FGIDs). In this context, microbiota-associated mediators are considered to act on specific receptors, thus affecting the enteric nervous system and, subsequently, GI motility. Thus, the pathophysiology of FGIDs is based on alterations of the gut microbiota/gut hormone axis, which have crucial effects on GI motility.

Effect of Pistacia atlantica kurdica gum on diabetic gastroparesis symptoms: a randomized, triple-blind placebo-controlled clinical trial

BACKGROUND

Gastroparesis is a recognized problem of type 1 and 2 diabetes mellitus that is defined by delayed gastric emptying. Due to insufficient satisfaction of current treatments, the use of complementary and alternative medicine in this field seems essential. According to Persian medicine, Pistacia atlantica gum has proper effect on gastrointestinal disorder specially stomach diseases.

OBJECTIVE

The aim of this study was to assess the effect of Pistacia atlantica gum on diabetic gastroparesis symptoms.

METHODS

A triple-blind randomized placebo-controlled trial on subjects with diabetic gastroparesis was conducted at the clinic of Imam Reza Hospital in Mashhad city in Iran, from November 2016 to May 2017. Fifty-four patients (16.7% males and 83.3% females) enrolled in the 8-week study and were randomly divided into two groups of intervention Pistacia atlantica and placebo groups. Both of the groups had received current dietary advice. Severity of gastroparesis symptoms was assessed with a Gastroparesis cardinal symptom index (GCSI) questionnaire. SPSS software version 16 was used to analyze the data and Generalized Estimating Equation (GEE) model, Independent-samples t-test, Paired-samples t-test, Mann-Whitney U test, and Wilcoxon signed-rank test were used to assess variables.

RESULTS

All gastroparesis symptoms of patients (14.6% diabetes type 1 and 85.4% diabetes type 2) including nausea/vomiting, postprandial fullness/early satiety, and bloating were significantly declined in each group during study (p<0.0001). Pistacia atlantica gum significantly reduced severity of gastroparesis symptoms including Postprandial fullness/early satiety (p=0.04), Bloating (p<0.0001), and GCSI scores (p=0.001) versus placebo. Systolic blood pressure (p=0.006), BMI (p=0.018), and HbA1c (p=0.038) significantly decreased in the Pistacia atlantica group after the intervention.

CONCLUSION

This study showed that daily consumption of Pistacia atlantica gum for one month improves diabetic gastroparesis symptoms.

TRIAL REGISTRATION

The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the code of IRCT2016110630739N1.

FUNDING

This study was supported by funding (grant no.: 950153) from the Mashhad University of Medical Sciences Research Council, Mashhad, Iran.

Gastroparesis Updates on Pathogenesis and Management

Gastroparesis (Gp) is a chronic disease that presents with clinical symptoms of early satiety, bloating, nausea, vomiting, and abdominal pain. Along with these symptoms, an objective finding of delayed gastric emptying, along with a documented absence of gastric outlet obstruction, are required for diagnosis. This article focuses on updates in the pathogenesis and management of Gp. Recent studies on full thickness biopsies of Gp patients have shed light on the complex interactions of the central, autonomic, and enteric nervous systems, which all play key roles in maintaining normal gut motility. The management of Gp has evolved beyond prokinetics and antiemetics with the use of gastric electrical stimulators (GES). In addition, this review aims to introduce the concept of gastroparesis-like syndrome (GLS). GLS helps groups of patients who have the cardinal symptoms of Gp but have a normal or rapid emptying test. Recent tests have shown that patients with Gp and GLS have similar pathophysiology, benefit greatly from GES placement, and likely should be treated in a similar manner.

Glass half empty? Lessons learned about gastroparesis

Gastroparesis is defined as a combination of chronic dyspeptic symptoms and delayed emptying of a solid test meal. It remains a difficult-to-treat disorder with a significant impact on quality of life. Although gastroparesis is defined by delayed emptying, several important studies did not find a correlation between this biomarker and symptom severity or treatment success. Thus, some of the more recent trials explored strategies that ranged from antiemetics to antidepressants. Although dietary management showed benefit, most of the other interventions were barely superior to placebo or were not superior at all. Placebo responses were often quite high and this complicates the assessment of active agents. While it complicates the design and interpretation of clinical trials, high response rates for active and sham interventions indicate that we can achieve symptom relief in many patients and thus give them some reassurance. If indeed most therapies are only marginally better than placebo, the differences in adverse effects should be weighed more strongly, a point that is especially important in view of the controversy surrounding metoclopramide. Mechanistic studies introduced the network of macrophages as another potentially important player in the development of gastroparesis. Results are too preliminary and are largely based on preclinical data but show up- and downregulation of cellular elements controlling gastric function. Thus, future developments may teach us how they interfere with some of these mechanisms in clinical settings, potentially making gastroparesis a reversible process.

The Investigation and Treatment of Diabetic Gastroparesis

PURPOSE

This review provides an update on the investigations and treatment options for gastroparesis.

METHODS

A comprehensive literature search of Medline, PubMed, Embase and OVID was conducted which included all systematic reviews and research articles that focused on the diagnosis, investigations and management diabetic gastroparesis.

FINDINGS

Dietary modifications and pharmacologic treatment with prokinetics to increase gastric motility form the mainstay of treatment. However, the use of prokinetics is limited by adverse effects and serious adverse effects, leaving metoclopramide as the only drug approved by the US Food and Drug Administration for the treatment of gastroparesis. Newer therapies, including motilin receptor agonists, ghrelin receptor agonists, and neurokinin receptor antagonists, are currently being investigated. Transpyloric stenting, gastric electrical stimulation, and gastric per-oral endoscopic myotomy provide mechanical options for intervention, and surgical interventions in severe intractable gastroparesis include laparoscopic pyloroplasty or gastrectomy.

IMPLICATIONS

Advances to better understand the pathophysiology and management of diabetic gastroparesis have been limited, especially with discordance between symptoms and severity of delay in gastric emptying. Established treatment options are limited; however, recent pharmacologic and surgical interventions show promise.

Manometric evaluation of the motilin receptor agonist camicinal (GSK962040) in humans

BACKGROUND

The gut hormone motilin stimulates gastrointestinal motility by inducing gastric phase III of the migrating motor complex (MMC) and enhancing the rate of gastric emptying. Camicinal (GSK962040), a small molecule motilin receptor agonist, has been shown to increase gastrointestinal motility.

METHODS

In this proof of concept study the effects of camicinal on MMC activity, esophageal and gastric pH was evaluated in eight healthy volunteers as a secondary endpoint. Doses of 50 and 150 mg were compared to placebo for a period of 24 hours in a double-blinded randomized crossover trial.

KEY RESULTS

The 50 mg dose (n=4) of camicinal had no significant impact on gastroduodenal manometry or pH parameters. A single dose of 150 mg (n=4) induced a gastric phase III after 0:34 h (0:25-0:58), which was significantly faster compared to placebo (18:15 h (4:32-22:16); P=.03). Moreover, the high dose significantly increased the occurrence of gastric phase III contractions compared to placebo (12% vs 39%; P=.0003). This increase in gastric phase III contractions during a period of 24 hour was due to an increased occurrence of gastric phases III during the daytime (5% vs 50%; P=.0001). The same dose however did not affect small bowel manometry parameters or esophageal and gastric pH.

CONCLUSIONS AND INFERENCES

Considering its stimulating effect on the MMC and gastric emptying, camicinal is an attractive candidate for the treatment of gastroparesis and gastroesophageal reflux disease. This trial was registered at clinicaltrials.gov as NCT00562848.

Management of gastrointestinal complications in hereditary transthyretin amyloidosis: a single-center experience over 40 years

Hereditary transthyretin amyloidosis (ATTRm amyloidosis) is a rare disease caused by the deposition and accumulation of insoluble non-native transthyretin fibrils in the body. The disease inevitably results in widespread organ disruption, and poor life expectancy. The GI tract is one organ system vulnerable to disruption and, although the clinical presentation of the disease varies, GI involvement affects most patients with ATTRm amyloidosis. Areas covered: This article presents our experience with diagnosing and treating the GI symptoms of ATTRm amyloidosis patients at our center over the last 40 years, in the Swedish clustering area of the disease. Our aim is to help other physicians to better manage GI complications in patients with this rare but widespread condition. Expert commentary: GI symptoms are debilitating complications for ATTRm amyloidosis patients to experience, yet with the appropriate questioning and diagnosis methods, symptomatic treatments of these symptoms can be implemented to provide relief. Further, patients with fewer GI complications and a good nutritional status are also better candidates for liver transplantation which, in selected cases, is the best disease-modifying treatment of ATTRm amyloidosis to date.

From Harmful Treatment to Secondary Gain: Adverse Event Reporting in Dyspepsia and Gastroparesis

INTRODUCTION

Medical management of gastroparesis and functional dyspepsia remains difficult with several recent trials showing limited or no benefit. If treatment comes with only marginal improvements, concerns about adverse events become more relevant. We therefore examined the type and outcomes of side effects submitted to a public repository.

METHODS

We searched the Federal Adverse Event Reporting System for reports associated with the treatment of dyspepsia or gastroparesis. Demographic data, medications used and implicated, side effects, and outcomes were abstracted for the years 2004-2015.

RESULTS

Acid-suppressive agents and prokinetics were the most commonly listed medications with a stronger emphasis on prokinetics in gastroparesis. Submissions related to metoclopramide by far exceeded reports about other agents and mostly described tardive dyskinesia or other neurological concerns. They peaked around 2012, driven by submissions through legal workers. Most reports about metoclopramide described short-term use to prevent or treat nausea and vomiting. Concerns about acid-suppressive medications increased over time and spanned a wide spectrum of potential problems, including osteoporosis, worsening renal function, or cardiac events.

CONCLUSION

Despite biasing factors, such as pending legal action, the voluntary repository of adverse events provides insight into current medical practice and its associated risk. Knowing about common and uncommon, but potentially serious risks may enable patients and providers to decide on effective and safe management strategies.

Gastroparesis: Medical and Therapeutic Advances

Gastroparesis is a chronic, bothersome, and often disabling neuromuscular disorder of the upper gastrointestinal tract. The most frequently reported symptoms of gastroparesis include nausea, vomiting, epigastric pain, early satiety, and unintentional weight loss. Etiologies of gastroparesis include diabetes, connective tissue disorders, prior infection, mesenteric ischemia, and post-surgical complications. The largest category of gastroparesis patients is comprised of those in whom no definitive cause can be identified (idiopathic gastroparesis). The individual and societal burden of gastroparesis is substantial. It considerably reduces patients' quality of life accompanied by a significant negative impact to the healthcare system. The current treatments of gastroparesis are less than ideal. Dietary modification may improve symptoms in patients with mild disease. Metoclopramide is the only medication currently approved for the treatment of gastroparesis; however, it is associated with adverse effects in a sizable proportion of patients. Other medications are frequently employed to treat symptoms of nausea and vomiting, although technically all are used off-label since they are not FDA approved for the treatment of gastroparesis. These data highlight the need to identify novel, more effective treatment options for this disabling disease. This review will provide a brief synopsis on the epidemiology, etiology, and impact of gastroparesis, discussing new therapeutic advances.

Upper GI Disorders: Pathophysiology and Current Therapeutic Approaches

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

Disorders of gastrointestinal hypomotility

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

Relamorelin Reduces Vomiting Frequency and Severity and Accelerates Gastric Emptying in Adults With Diabetic Gastroparesis

BACKGROUND & AIMS

Gastroparesis is an important complication of diabetes. We investigated the effects of relamorelin (a pentapeptide-selective agonist of the ghrelin receptor that speeds gastric emptying in patients with diabetes) in patients with diabetic gastroparesis.

METHODS

We performed a double-blind trial of 204 patients (78% Caucasian; 67% female; mean age, 55 y; 88% with type 2 diabetes) with diabetic gastroparesis with moderate to severe symptoms and delayed gastric emptying at 27 clinical centers, from June 2012 until August 2013. Patients were assigned randomly (1:1:1) to groups given placebo or subcutaneous relamorelin 10 μg once or twice daily. The primary end point was the half-time of gastric emptying. Secondary end points included nausea, abdominal pain, bloating, early satiety, as well as the composite score of these 4 subjective symptoms and vomiting frequency and severity.

RESULTS

Twice-daily relamorelin significantly accelerated gastric emptying (P < .03) and reduced vomiting frequency (by ∼60%) and severity vs placebo (P ≤ .033). Compared with placebo, relamorelin did not improve other gastrointestinal symptoms, such as abdominal pain and satiety. In the 119 patients (58.3%) with baseline vomiting, twice-daily relamorelin significantly reduced the half-time of gastric emptying and vomiting, as well as nausea, abdominal pain, bloating, and early satiety compared with placebo (composite score, P = .043). No overall safety concerns were identified.

CONCLUSIONS

In a clinical trial of patients with diabetic gastroparesis, relamorelin (10 μg twice daily) significantly accelerated gastric emptying and significantly reduced vomiting, compared with placebo. Among patients with baseline vomiting, relamorelin had prokinetic effects and significantly reduced vomiting and also improved other symptoms of diabetic gastroparesis compared with placebo. ClincialTrials.gov number: NCT01571297.

Pharmacologic Treatment for Pediatric Gastroparesis: A Review of the Literature

There have been a number of agents that have been tried for treatment of gastroparesis over the past 3 decades, with varying levels of success. Guidelines exist for the management of gastroparesis in adults; however, even though the cause of gastroparesis in children is similar to that in adults, no guidelines exist for treating pediatric gastroparesis as studies on the topic are limited. With what little information we have on pediatric gastroparesis, medications used in children's studies do not seem to demonstrate the same results as in adult patients with gastroparesis; thus, future studies of whether certain medications are effective for treating pediatric gastroparesis and at what dose still need to be conducted. Pharmacological treatment options for pediatric gastroparesis do not show a clear correlation of resolving or even maintaining gastroparesis-associated symptoms or disease state. This article reviews the available studies of drugs that have shown some efficacy, with an emphasis on pediatric studies.

Systematic review and meta-analysis: Gastric electrical stimulation for gastroparesis

BACKGROUND

Controlled trials of gastric electrical stimulation (GES) for gastroparesis reported no significant improvement in symptoms, while open label studies suggested substantial clinical benefits.

AIM

To determine if GES is effective in reducing symptoms in patients with gastroparesis.

METHODS

We searched PubMed and Embase for articles published in English (1990-2014) using "gastroparesis" as a search term restricted to "clinical trial". We included studies describing repeated patient-based symptom ratings before and during standardized treatments of at least one week duration.

RESULTS

Five studies randomly allocated patients to periods with or without GES. Total symptom severity (TSS) scores did not differ between these periods (0.17 [95% confidence interval: -0.06 to 0.4]; P=0.15). However, sixteen open label studies of GES showed a significant TSS decrease (2.68 [2.04-3.32]; Q=39.0; P<0.001). Other treatment modalities similarly improved TSS by 1.97 [1.5-2.44] for medical therapy (MED), by 1.52 [0.9-2.15] for placebo arms (PLA), and by 2.32 [1.56-3.06] for botulinum toxin (BTx). There were significant differences in baseline TSS ratings among these studies (GES: 6.28 [6.28-7.42]; MED: 4.76 [4.09-5.42]; PLA: 4.59 [3.77-5.42]; BTx: 6.02 [5.3-6.74]; Q=35.1; P<0.001). Meta-regression analysis showed these baseline differences to significantly impact TSS ratings during treatment (Q=71.8; P<0.001).

CONCLUSION

Independent of the treatment modality, baseline symptom severity impacts treatment results in gastroparesis. Considering the skewed population with refractory symptoms, regression to the mean likely contributes to the substantial discrepancies between the reported results of controlled and open label GES studies, raising questions about the use of GES outside of defined clinical trials.

Randomized clinical trial: a controlled pilot trial of the 5-HT4 receptor agonist revexepride in patients with symptoms suggestive of gastroparesis

BACKGROUND

Gastroparesis is a chronic gastric disorder characterized by delayed gastric emptying without mechanical obstruction, and clinical symptoms as postprandial fullness, early satiety, bloating, nausea, vomiting, and abdominal pain. Prokinetic agents are used for the treatment of gastroparesis. Revexepride, a 5-hydroxytryptamine (serotonin) receptor (5-HT4 R) agonist, could be a good candidate drug for the gastroparesis treatment.

AIM

In the current phase II, exploratory, double-blind, randomized, stratified, placebo-controlled, repeated dose trial (EudraCT number 2007-004997-23), the efficacy on gastrointestinal symptoms and gastric emptying rate, safety, and pharmacokinetic profile of three oral doses of revexepride (0.02, 0.1, and 0.5 mg administered orally t.i.d. for 4 weeks) was evaluated in trial participants (diabetic and non-diabetic) with upper gastrointestinal tract symptoms suggestive for gastroparesis.

METHODS

Eighty participants, enrolled in four parallel treatment groups, were asked to score their symptom diary data, gastroparesis cardinal symptom index (GCSI), patient assessment of upper gastrointestinal disorders-symptom severity index (PAGI-SYM), quality of life questionnaires, and meal-related symptom score. Gastric emptying rate was evaluated by (13) C-octanoic acid breath test.

KEY RESULTS

The severity of the symptoms assessed by means of GCSI and PAGI-SYM decreased at Week 2 and decreased further at Week 4 in all treatment groups including placebo, with similar trends in all treatment groups. Quality of life improved in all treatment groups after 4 weeks of treatment. No differences on gastric emptying rate were shown between any of the active treatment groups and placebo. Revexepride was generally safe and well-tolerated.

CONCLUSIONS & INFERENCES

Four weeks of revexepride treatment did not improve symptoms or gastric emptying over placebo in patients with symptoms suggestive of gastroparesis.

Current and Emerging Medical Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis likely involves various pathophysiological disorders and is increasingly prevalent as complications of surgeries, medications, and chronic diabetes. Key to diagnosis is evidence of delayed gastric emptying, generally based on standardized scintigraphy, and ruling out distal obstruction or other dysmotilities. Initial medical management includes reviewing potentially exacerbating medications and ruling out other reversible causes, achieving tighter glucose control in diabetics, and implementing dietary and lifestyle changes. While current available medications are limited, symptomatic control is aimed at improving gastric emptying, alleviating nausea and vomiting, and treating associated abdominal pain. Other potential therapies are aimed at reducing acid production, improving gastric accommodation or pyloric dysfunction, and treating bacterial overgrowth. Future studies should be aimed toward identification of subpopulations of gastroparetics who are better responders to the various medications based on differences in underlying pathophysiology and adopting standardized study end point measures that may allow for comparisons across trials. This chapter will review current treatment options, upcoming promising medications, and some of the hurdles in advancing the field forward.

Medical treatment of functional dyspepsia

Functional dyspepsia (FD) is a condition in which upper abdominal symptoms, such as epigastralgia, postprandial discomfort, and bloating, occur in the absence of any organic or metabolic disease that could explain the symptoms. The prevalence of FD is increasing, presumably because of an increasingly stressful environment, as well as overlap with other motility disorders such as gastroesophageal reflux diseases and irritable bowel syndrome. Numerous studies have attempted to determine the pathophysiological mechanisms of FD and establish effective FD treatment, with little success. Several therapeutic options have been explored, including Helicobacter pylori eradication, proton pump inhibitors, prokinetic agents, anti-depressant and anxiolytic agents, and acotiamide, a recent emerging drug. Through the many trials evaluating the efficacy of drugs for FD treatment, we found that it is necessary to treat according to the symptoms of FD and to use a combination of therapeutic options. Additional well-designed, prospective studies are needed to confirm the management of FD.

Gastric emptying and glycaemia in health and diabetes mellitus

The rate of gastric emptying is a critical determinant of postprandial glycaemia and, accordingly, is fundamental to maintaining blood glucose homeostasis. Disordered gastric emptying occurs frequently in patients with longstanding type 1 diabetes mellitus and type 2 diabetes mellitus (T2DM). A complex bidirectional relationship exists between gastric emptying and glycaemia--gastric emptying accounts for ∼35% of the variance in peak postprandial blood glucose concentrations in healthy individuals and in patients with diabetes mellitus, and the rate of emptying is itself modulated by acute changes in glycaemia. Clinical implementation of incretin-based therapies for the management of T2DM, which diminish postprandial glycaemia, in part by slowing gastric emptying, is widespread. Other therapies for patients with T2DM, which specifically target gastric emptying include pramlintide and dietary-based treatment approaches. A weak association exists between upper gastrointestinal symptoms and the rate of gastric emptying. In patients with severe diabetic gastroparesis, pathological changes are highly variable and are characterized by loss of interstitial cells of Cajal and an immune infiltrate. Management options for patients with symptomatic gastroparesis remain limited in their efficacy, which probably reflects the heterogeneous nature of the underlying pathophysiology.

Time trends in gastroparesis treatment

INTRODUCTION

While delayed emptying is the defining criterion for gastroparesis, prokinetics often only have a limited impact on symptoms and have been associated with potentially serious adverse effects. The goal of this study was to determine how this information and regulatory changes affected gastroparesis management.

METHODS

The electronic medical records of patients seen between 2003 and 2012 in the outpatient clinic of a large tertiary center were retrieved based on the billing diagnosis of gastroparesis. Demographic, clinical, and survival data were abstracted.

RESULTS

A total of 709 patients were identified, with diabetes (21.2 %) and prior surgery (9.8 %) being the most common identifiable causes. The majority of patients (56 %) had idiopathic gastroparesis. The cohort was female predominant (79.5 %) with an average age of 45.4 ± 0.6 years. At the index encounter, 61.8 % received prokinetics. About one-third (37.7 %) used antiemetics at least intermittently. Between 2003 and 2012, prokinetic use dropped from 81 to 43 %, while the use of antiemetics increased from 14 to 41 %. Similarly, there was a significant increase in prescribed opioids and antidepressants. During the period of the study, 44 patients (6.2 %) died. Increasing age, a higher comorbidity burden, anxiety, and medication use were associated with higher mortality risks.

CONCLUSION

This large outpatient cohort suggests that treatment trends move away from prokinetics and focus on symptom-oriented therapy and/or confounding mood disorders.

Management of gastroparesis: beyond basics

OPINION STATEMENT

Gastroparesis is defined as the presence of delayed gastric emptying in the absence of mechanical obstruction, with a variety of upper gastrointestinal symptoms. Although measurement of gastric emptying is necessary for the diagnostic labeling, this finding has little impact in terms of explaining the symptom pattern and determining the prognosis and therapeutic approach. Clinical management is based on ruling out of mechanical causes and serum electrolyte imbalances, followed by initial medical treatment with a gastroprokinetic agent in most cases. However, the evidence that these drugs provide substantial symptomatic benefit is weak. Recent attempts to establish efficacy with newer prokinetics, including serotonin-4, motilin, and ghrelin receptor agonists, have seen few successes, but a new group of agents is under evaluation. More recently, also, no benefit was found with treatment with a tricyclic antidepressant in idiopathic gastroparesis. In refractory cases, especially when there is weight loss, invasive therapeutics such as insertion of feeding tubes, intrapyloric injection of botulinum toxin, implantable gastric electrical stimulation, or surgical (partial) gastrectomy are occasionally considered, but there is little evidence of efficacy, and these are not devoid of potentially major complications. Gastroparesis is likely to remain a challenging condition in the clinic in the foreseeable future.

ER stress and ER stress-induced apoptosis are activated in gastric SMCs in diabetic rats

AIM: To investigate the gastric muscle injury caused by endoplasmic reticulum (ER) stress in rats with diabetic gastroparesis.

METHODS: Forty rats were randomly divided into two groups: a control group and a diabetic group. Diabetes was induced by intraperitoneal injection of 60 mg/kg of streptozotocin. Gastric emptying was determined at the 4^th and 12^th week. The ultrastructural changes in gastric smooth muscle cells (SMCs) were investigated by transmission electron microscopy. TdT-mediated dUTP nick end labeling (TUNEL) assay was performed to assess apoptosis of SMCs. Expression of the ER stress marker, glucose-regulated protein 78 (GRP78), and the ER-specific apoptosis mediator, caspase-12 protein, was determined by immunohistochemistry.

RESULTS: Gastric emptying was significantly lower in the diabetic rats than in the control rats at the 12^th wk (40.71% ± 2.50%, control rats vs 54.65% ± 5.22%, diabetic rats; P < 0.05). Swollen and distended ER with an irregular shape was observed in gastric SMCs in diabetic rats. Apoptosis of gastric SMCs increased in the diabetic rats in addition to increased expression of GRP78 and caspase-12 proteins.

CONCLUSION: ER stress and ER stress-mediated apoptosis are activated in gastric SMCs in diabetic rats with gastroparesis.

Effect of nortriptyline on symptoms of idiopathic gastroparesis: the NORIG randomized clinical trial

IMPORTANCE

Gastroparesis remains a challenging syndrome to manage, with few effective treatments and a lack of rigorously controlled trials. Tricyclic antidepressants are often used to treat refractory symptoms of nausea, vomiting, and abdominal pain. Evidence from well-designed studies for this use is lacking.

OBJECTIVE

To determine whether treatment with nortriptyline results in symptomatic improvement in patients with idiopathic gastroparesis.

DESIGN, SETTING, AND PARTICIPANTS

The NORIG (Nortriptyline for Idiopathic Gastroparesis) trial, a 15-week multicenter, parallel-group, placebo-controlled, double-masked, randomized clinical trial from the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Clinical Research Consortium (GpCRC), comparing nortriptyline with placebo for symptomatic relief in idiopathic gastroparesis. One hundred thirty patients with idiopathic gastroparesis were enrolled between March 2009 and June 2012 at 7 US academic medical centers. Patient follow-up was completed in October 2012. Inclusion criteria included delayed gastric emptying and moderate to severe symptom scores using the Gastroparesis Cardinal Symptom Index (GCSI). INTERVENTIONS Nortriptyline vs placebo. Study drug dose was increased at 3-week intervals (10, 25, 50, 75 mg) up to 75 mg at 12 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome measure of symptomatic improvement was a decrease from the patient's baseline GCSI score of at least 50% on 2 consecutive 3-week GCSI assessments during 15 weeks of treatment.

RESULTS

The primary symptomatic improvement outcome did not differ between 65 patients randomized to nortriptyline vs 65 patients randomized to placebo: 15 (23% [95% CI, 14%-35%]) in the nortriptyline group vs 14 (21% [95% CI, 12%-34%]) in the placebo group (P = .86). Treatment was stopped more often in the nortriptyline group (19 [29% {95% CI, 19%-42%}]) than in the placebo group (6 [9%] {95% CI, 3%-19%}]) (P = .007), but numbers of adverse events were not different (27 [95% CI, 18-39] vs 28 [95% CI, 19-40]) (P = .89).

CONCLUSIONS AND RELEVANCE

Among patients with idiopathic gastroparesis, the use of nortriptyline compared with placebo for 15 weeks did not result in improvement in overall symptoms. These findings do not support the use of nortriptyline for idiopathic gastroparesis.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00765895.

DA-9701: A New Multi-Acting Drug for the Treatment of Functional Dyspepsia

Motilitone^® (DA-9701) is a new herbal drug that was launched for the treatment of functional dyspepsia in December 2011 in Korea. The heterogeneous symptom pattern and multiple causes of functional dyspepsia have resulted in multiple drug target strategies for its treatment. DA-9701, a compound consisting of a combination of Corydalis Tuber and Pharbitidis Semen, has being developed for treatment of functional dyspepsia. It has multiple mechanisms of action such as fundus relaxation, visceral analgesia, and prokinetic effects. Furthermore, it was found to significantly enhance meal-induced gastric accommodation and increase gastric compliance in dogs. DA-9701 also showed an analgesic effect in rats with colorectal distension induced visceral hypersensitivity and an antinociceptive effect in beagle dogs with gastric distension-induced nociception. The pharmacological effects of DA-9701 also include conventional effects, such as enhanced gastric emptying and gastrointestinal transit. The safety profi le of DA-9701 is also preferable to that of other treatments.

Neurochemical mechanisms and pharmacologic strategies in managing nausea and vomiting related to cyclic vomiting syndrome and other gastrointestinal disorders

Nausea and vomiting are common gastrointestinal complaints which could be triggered by stimuli in both the peripheral and central nervous systems. They may be considered as defense mechanisms when threatening toxins/agents enter the gastrointestinal tract or there is excessive retention of gastrointestinal contents due to obstruction. The pathophysiology of nausea and vomiting is complex and much still remains unknown. Therefore, treatments are restricted or ineffective in many cases. Nausea and vomiting with functional etiologies including cyclic vomiting syndrome are challenging in gastroenterology. In this article, we review potential pathways, neurochemical transmitters, and their receptors which are possibly involved in the pathophysiology of nausea and vomiting including the entity cyclic vomiting syndrome.

Delayed gastric emptying in Parkinson's disease

Gastrointestinal symptoms are evident in all stages of Parkinson's disease (PD). Most of the gastrointestinal abnormalities associated with PD are attributable to impaired motility. At the level of the stomach, this results in delayed gastric emptying. The etiology of delayed gastric emptying in PD is probably multifactorial but is at least partly related to Lewy pathology in the enteric nervous system and discrete brainstem nuclei. Delayed gastric emptying occurs in both early and advanced PD but is underdetected in routine clinical practice. Recognition of delayed gastric emptying is important because it can cause an array of upper gastrointestinal symptoms, but additionally it has important implications for the absorption and action of levodopa. Delayed gastric emptying contributes significantly to response fluctuations seen in people on long-term l-dopa therapy. Neurohormonal aspects of the brain-gut axis are pertinent to discussions regarding the pathophysiology of delayed gastric emptying in PD and are also hypothesized to contribute to the pathogenesis of PD itself. Ghrelin is a gastric-derived hormone with potential as a therapeutic agent for delayed gastric emptying and also as a novel neuroprotective agent in PD. Recent findings relating to ghrelin in the context of PD and gastric emptying are considered. This article highlights the pathological abnormalities that may account for delayed gastric emptying in PD. It also considers the wider relevance of abnormal gastric pathology to our current understanding of the etiology of PD.

Pathophysiology and pharmacotherapy of gastroparesis: current and future perspectives

INTRODUCTION

Gastroparesis is an important clinical disorder characterised by delayed gastric emptying in the absence of mechanical outlet obstruction. Idiopathic, diabetes and postsurgical causes represent the most common aetiologies. The condition commonly manifests as upper gastrointestinal symptoms, including nausea, vomiting, postprandial fullness, early satiety, abdominal pain and bloating.

AREAS COVERED

This paper provides a review of the prevalence, pathophysiology and clinical features associated with gastroparesis, with a particular focus on current pharmacological management options and novel and emerging therapies. A literature search was undertaken using the search terms: gastroparesis, diabetic gastroparesis, idiopathic gastroparesis, gastric emptying, prokinetic, metoclopramide, domperidone, erythromycin, motilin, alemcinal, KC11458, mitemcinal, ghrelin, TZP-101, TZP-102, RM-131, tegaserod, prucalopride, naronapride, velusetrag, levosulpiride, itopride, botulinum toxin, gastric electrical stimulation, Enterra.

EXPERT OPINION

Strategies for the management of gastroparesis include correction of malnutrition, dehydration and electrolyte imbalance, relief of symptoms by appropriate use of prokinetic and antiemetic agents and, in patients with gastroparesis associated with diabetes or critical illness-induced hyperglycaemia, optimisation of glycaemic control. Conventional prokinetic agents form the mainstay of treatment. While novel pharmacotherapies are in development, compelling evidence for their efficacy, particularly in symptom relief, remains to be established.

Recent advances in the pathophysiology and treatment of gastroparesis

Gastroparesis is a clinical disorder characterized by upper gastrointestinal symptoms related with delayed gastric emptying of solids and liquids in the absence of mechanical obstruction. Diabetes mellitus has been the most common cause of gastroparesis and idiopathic gastroparesis also accounts for a third of all chronic cases. The most important mechanisms of gastroparesis, as understood to date, are loss of expression of neuronal nitric oxide synthase and loss of the interstitial cells of Cajal. However, the pathogenesis of gastroparesis is poorly understood. There have been several studies on specific molecules related to the pathogenesis of gastroparesis. Additionally, the Gastroparesis Clinical Research Consortium of the National Institutes of Health has achieved several promising results regarding the pathophysiology of gastroparesis. As the progress in the pathophysiology of gastroparesis has been made, a promising new drug therapy has been found. The pathophysiology and drug therapy of gastroparesis are focused in this review. Until now, the real-world medication options for treatment of gastroparesis are limited. However, it is expected to be substantially improved as the pathophysiology of gastroparesis is elucidated.