Gastroparesis: a turning point in understanding and treatment

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

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

The enteric nervous system in gastrointestinal disease etiology

A highly conserved but convoluted network of neurons and glial cells, the enteric nervous system (ENS), is positioned along the wall of the gut to coordinate digestive processes and gastrointestinal homeostasis. Because ENS components are in charge of the autonomous regulation of gut function, it is inevitable that their dysfunction is central to the pathophysiology and symptom generation of gastrointestinal disease. While for neurodevelopmental disorders such as Hirschsprung, ENS pathogenesis appears to be clear-cut, the role for impaired ENS activity in the etiology of other gastrointestinal disorders is less established and is often deemed secondary to other insults like intestinal inflammation. However, mounting experimental evidence in recent years indicates that gastrointestinal homeostasis hinges on multifaceted connections between the ENS, and other cellular networks such as the intestinal epithelium, the immune system, and the intestinal microbiome. Derangement of these interactions could underlie gastrointestinal disease onset and elicit variable degrees of abnormal gut function, pinpointing, perhaps unexpectedly, the ENS as a diligent participant in idiopathic but also in inflammatory and cancerous diseases of the gut. In this review, we discuss the latest evidence on the role of the ENS in the pathogenesis of enteric neuropathies, disorders of gut-brain interaction, inflammatory bowel diseases, and colorectal cancer.

Transient delayed gastric emptying following laparoscopic Nissen fundoplication for gastroesophageal reflux disease

PURPOSE

Although laparoscopic Nissen fundoplication (LNF) is a kind of minimally invasive surgery, some transition time may still be required to allow the fundoplicated stomach to adapt to the new anatomical position. We observed transient delayed gastric emptying (DGE) post-LNF in our preliminary study. This study aimed to investigate the occurrence rate and development of transient DGE post-LNF.

METHODS

Patients who underwent LNF for gastroesophageal reflux disease (GERD) at our institution were recruited consecutively. They were treated with standardized LNF and prospectively followed up for 2 months. Proper diet guidance and/or pharmacologic therapy were given during these 2 months. GERD Health-Related Quality of Life (GERD-HRQL), DGE symptoms, and DGE status were evaluated preoperatively and postoperatively.

RESULTS

Fifty-one patients underwent LNF and completed a 2-month follow-up. LNF succeeded in all patients. Prior to LNF, no DGE was identified. At the 1-month follow-up, LNF led to a significant reduction in the GERD-HRQL total score but a significantly increased DGE score. Endoscopically, DGE was identified in forty-seven (n = 47, 92.2%) patients. At the 2-month follow-up, the GERD-HRQL scores continued to show decreases compared to the 1 month. The DGE score returned to the baseline value. Endoscopically, no DGE was identified in any patients (n = 0, 0.0%).

CONCLUSIONS

Transient DGE is a very common one-month post-LNF but can recover quickly in the second month following LNF.

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.

Electroacupuncture Regularizes Gastric Contraction and Reduces Apoptosis of Interstitial Cells of Cajal in Diabetic Rats

Background/Aims

Gastric dysmotility is a frequent complication among patients with diabetes mellitus. Electroacupuncture (EA) has been empirically used to relieve gastrointestinal symptoms. The aims of this study were to investigate the effects of EA on gastric contraction and the mechanisms of interstitial cells of Cajal (ICC) involved.

Materials and Methods

Male Sprague–Dawley rats were randomized into the normal control, diabetes (DM), diabetic and sham EA (DM + SEA), diabetic and low-frequency EA (DM + LEA), and diabetic and high-frequency EA (DM + HEA) groups. Diabetic models were established and then treated with EA for 8 weeks. Body weight and blood glucose were recorded every 2 weeks. The spontaneous contractions of distal gastric strips were analyzed. Immunostaining and RT-PCR were used to test the apoptotic ICC, IGF-1/IGF-1R, and Nrf2/HO-1 pathways.

Results

The body weight in the DM + LEA and DM + HEA groups were increased compared with that of the DM group, though there was no effect on the blood glucose. The gastric contractions were obviously disordered in the DM group, but EA could regularize the contractions. The number of apoptotic ICC was dramatically increased in the DM group, but reduced with EA treatment. Meanwhile, the IGF-1/IGF-1R pathway was verified to be significantly altered in diabetic rats. The Nrf2/HO-1 pathway was not significantly increased in the DM group. EA with different frequencies efficiently improved the expression of IGF-1/IGF-1R signaling and activated the Nrf2/HO-1 pathway.

Conclusion

EA could improve gastric motility dysfunction and attenuate ICC apoptosis possibly through the regulation of IGF-1/IGF-1R and Nrf2/HO-1 pathways. EA may be a potential therapeutic method for diabetic gastric motility dysfunction.

Current challenges and future perspectives in oral absorption research: An opinion of the UNGAP network

Although oral drug delivery is the preferred administration route and has been used for centuries, modern drug discovery and development pipelines challenge conventional formulation approaches and highlight the insufficient mechanistic understanding of processes critical to oral drug absorption. This review presents the opinion of UNGAP scientists on four key themes across the oral absorption landscape: (1) specific patient populations, (2) regional differences in the gastrointestinal tract, (3) advanced formulations and (4) food-drug interactions. The differences of oral absorption in pediatric and geriatric populations, the specific issues in colonic absorption, the formulation approaches for poorly water-soluble (small molecules) and poorly permeable (peptides, RNA etc.) drugs, as well as the vast realm of food effects, are some of the topics discussed in detail. The identified controversies and gaps in the current understanding of gastrointestinal absorption-related processes are used to create a roadmap for the future of oral drug absorption research.

A link between gastrointestinal disorders and migraine: Insights into the gut-brain connection

Background

Migraine is a complex, multifaceted, and disabling headache disease that is often complicated by gastrointestinal (GI) conditions, such as gastroparesis, functional dyspepsia, and cyclic vomiting syndrome (CVS). Functional dyspepsia and CVS are part of a spectrum of disorders newly classified as disorders of gut–brain interaction (DGBI). Gastroparesis and functional dyspepsia are both associated with delayed gastric emptying, while nausea and vomiting are prominent in CVS, which are also symptoms that commonly occur with migraine attacks. Furthermore, these gastric disorders are comorbidities frequently reported by patients with migraine. While very few studies assessing GI disorders in patients with migraine have been performed, they do demonstrate a physiological link between these conditions.

Objective

To summarize the available studies supporting a link between GI comorbidities and migraine, including historical and current scientific evidence, as well as provide evidence that symptoms of GI disorders are also observed outside of migraine attacks during the interictal period. Additionally, the importance of route of administration and formulation of migraine therapies for patients with GI symptoms will be discussed.

Methods

A literature search of PubMed for articles relating to the relationship between the gut and the brain with no restriction on the publication year was performed. Studies providing scientific support for associations of gastroparesis, functional dyspepsia, and CVS with migraine and the impact these associations may have on migraine treatment were the primary focus. This is a narrative review of identified studies.

Results

Although the association between migraine and GI disorders has received very little attention in the literature, the existing evidence suggests that they may share a common etiology. In particular, the relationship between migraine, gastric motility, and vomiting has important clinical implications in the treatment of migraine, as delayed gastric emptying and vomiting may affect oral dosing compliance, and thus, the absorption and efficacy of oral migraine treatments.

Conclusions

There is evidence of a link between migraine and GI comorbidities, including those under the DGBI classification. Many patients do not find adequate relief with oral migraine therapies, which further necessitates increased recognition of GI disorders in patients with migraine by the headache community.

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.

Diabetic and Non-Diabetic Gastroparesis: A Retrospective Comparative Outcome Study From the Nationwide Inpatient Sample

Background

Gastroparesis (GP), meaning “gastric palsy”, is a chronic medical condition characterized by delayed or absent gastric emptying in the absence of mechanical obstruction. The primary objective of this study was to determine the patient-specific outcomes and the burden of GP on the US healthcare system.

Methods

This was a population-based, retrospective study designed to analyze data available from the Nationwide Inpatient Sample (NIS) for 2016 and 2017. Using the International Classification of Diseases, Tenth Revision (ICD-10) codes, we identified adult (18 years or older) hospitalizations with a principal diagnosis of GP. The study sample was further classified into two distinct groups based on the presence or absence of GP, namely diabetic GP (DGP) and non-diabetic GP (NDGP). The primary outcome of our study was inpatient mortality secondary to GP while the secondary outcomes included the odds of system-based complications and the burden of the disease on the United States healthcare system.

Results

We identified 99,695 adult (≥ 18 years) hospitalizations with a principal discharge diagnosis of GP in 2016 and 2017. Of these patients, 78.1% (77,885) had DGP and 21.9% (21,810) were classified in the NDGP group. We noted a higher proportion of women (79.3% vs. 63.4%, P < 0.001), patients with a history of smoking (35.8% vs. 31.7%, P < 0.001) and chronic obstructive pulmonary disease (10.7% vs. 7.6%, P < 0.001) in the NDGP group. After adjusting for common confounders excluding age, the inpatient mortality for GP was found to be 0.25%. Furthermore, after adjustments were made for the Charlson comorbidity index (CCI), we noted higher odds of mortality in the NDGP group (0.30% vs. 0.23%, adjusted odds ratio (aOR): 3.18, 95% confidence interval (CI): 1.75 - 5.79, P < 0.001) compared to the DGP group. Additionally, patients with NDGP had a higher mean length of stay (5 vs. 4.1 days, P < 0.001) and higher mean total hospital charge ($44,100 vs. $35,500, P < 0.001) compared to those with DGP. The NDGP group also had higher odds of sepsis, deep vein thrombosis (DVT) and pulmonary embolism (PE); however, the odds of developing acute kidney injury (AKI) were lower than that of the DGP group.

Conclusions

The inpatient mortality for GP was found to be 0.25%. After adjusting for CCI, patients with NDGP had higher odds of inpatient mortality compared to the DGP group. Additionally, patients with NDGP were associated with a longer length of hospital stay, mean total healthcare cost and higher odds of complications such as sepsis, DVT and PE during the hospitalization.

Ultrasound imaging for assessing functions of the GI tract

OBJECTIVE

In the following review we outline how ultrasound can be used to measure physiological processes in the gastrointestinal tract.

APPROACH

We have investigated the potential of ultrasound in assessing gastrointestinal physiology including original research regarding both basic methodology and clinical applications.

MAIN RESULTS

Our main findings show the use of ultrasound to study esophageal motility, measure volume and contractility of the stomach, assess motility, wall thickness, and perfusion of the small bowel, and evaluate wall vascularization and diameters of the large bowel.

SIGNIFICANCE

Ultrasound is a widely accessible technology that can be used for both scientific and clinical purposes. Being radiation-free and user friendly, the examination can be frequently repeated enabling longitudinal studies. Furthermore, it does not influence normal GI physiology, thus being useful to estimate motility and subtle changes in physiology. Accordingly, ultrasound scanning and physiological measurements may make a big difference for the scientist and the doctor; and for the patients who receive an efficient work-up.

Gastric peroral endoscopic pyloromyotomy for decompensated gastroparesis: comprehensive motility analysis in relation to treatment outcomes

Background and study aims  There are no reliable data to predict which patients with gastroparesis (GP) would benefit the most from gastric peroral endoscopic pyloromyotomy (G-POEM). The aim of the present study was to assess whether antro-duodenal motility patterns and pyloric distensibility can predict the outcome of G-POEM in patients with decompensated GP. Patients and methods  In an open-label study, patients with GP and refractory symptoms were eligible for treatment with G-POEM if treatment attempts according to a standardized stepwise protocol had failed. Baseline assessment included Gastroparesis Cardinal Symptom Index (GCSI), C13-octanoic gastric emptying breath test and high-resolution antro-duodenal manometry. Pyloric distensibility using EndoFlip measurements was assessed at baseline and 3 months after the procedure. Explorative analyses were performed on potential predictors of response using logistic regression analyses. Results  Twenty-four patients with decompensated GP underwent G-POEM. At baseline, 78.3 % and 61.9 % of patients showed antral hypomotility and neuropathic motor patterns, respectively. The technical success rate was 100 % (24/24). Mean GCSI improved significantly at 3, 6, and 12 months after G-POEM ( P  = 0.01). Median distensibility index (DI) improved significantly as compared with baseline (7.5 [6.9;11.7] vs. 5.3[3.1;8.1], P  = 0.004). A significant correlation was found between clinical response at 6 months and pyloric DI improvement ( P  = 0.003). No potential predictors of clinical response after G-POEM could be identified in an explorative analysis. Conclusions  G-POEM improved pyloric distensibility patterns in patients with decompensated GP. Clinical response at 6 months after G-POEM was associated with pyloric distensibility improvement. However, no potential predictors of response could be identified from either antro-duodenal motility patterns or pyloric distensibility.

Knowledge, Attitude, and Practice Survey of Gastroparesis in Asia by Asian Neurogastroenterology and Motility Association

Background/Aims

Gastroparesis is identified as a subject that is understudied in Asia. The scientific committee of the Asian Neurogastroenterology and Motility Association performed a Knowledge, Attitude, and Practices survey on gastroparesis among doctors in Asia.

Methods

The questionnaire was created and developed through a literature review of current gastroparesis works of literature by the scientific committee of Asian Neurogastroenterology and Motility Association.

Results

A total of 490 doctors from across Asia (including Bangladesh, China, Hong Kong, Indonesia, Japan, Malaysia, Myanmar, the Philippines, Singapore, South Korea, Taiwan, Thailand, and Vietnam) participated in the survey. Gastroparesis is a significant gastrointestinal condition. However, a substantial proportion of respondents was unable to give the correct definition and accurate diagnostic test. The main reason for lack of interest in diagnosing gastroparesis was "the lack of reliable diagnostic tests" (46.8%) or "a lack of effective treatment" (41.5%). Only 41.7% of respondents had access to gastric emptying scintigraphy. Most doctors had never diagnosed gastroparesis at all (25.2%) or diagnosed fewer than 5 patients a year (52.1%).

Conclusions

Gastroparesis can be challenging to diagnose due to the lack of instrument, standardized method, and paucity of research data on normative value, risk factors, and treatment studies in Asian patients. Future strategies should concentrate on how to disseminate the latest knowledge of gastroparesis in Asia. In particular, there is an urgent need to estimate the magnitude of the problems in high risk and idiopathic patients as well as a standardized diagnostic procedure in Asia.

Gut Microbial Dysbiosis in the Pathogenesis of Gastrointestinal Dysmotility and Metabolic Disorders

Of all microorganisms in the human body, the largest and most complex population resides in the gastrointestinal (GI) tract. The gut microbiota continuously adapts to the host environment and serves multiple critical functions for their hosts, including regulating host immunity, procuring energy from food, and preventing the colonization of pathogens. Mounting evidence has suggested gut microbial imbalance (dysbiosis) as a core pathophysiology in the development of GI motility and metabolic disorders, such as irritable bowel syndrome and diabetes. Current research has focused on discovering associations between these disorders and gut microbial dysbiosis; however, whether these associations are a consequence or cause is still mostly unexplored. State-of-the-art studies have investigated how gut microbes communicate with our body systems through microbiota-derived metabolites and how they are able to modulate host physiology. There is now mounting evidence that alterations in the composition of small intestinal microbes have an association with GI dysmotility and metabolic disorders. Although treatment options for gut microbial dysbiosis are currently limited, antibiotics, fecal microbiota transplantation, probiotics, and dietary interventions are currently the best options. However, treatment with broad-spectrum antibiotics has been viewed with skepticism due to the risk of developing antibiotic resistant bacteria. Studies are warranted to elucidate the cellular and molecular pathways underlying gut microbiota-host crosstalk and for the development of a powerful platform for future therapeutic approaches. Here, we review recent literature on gut microbial alterations and/or interactions involved in the pathophysiology of GI dysmotility and metabolic disorders.

Duodenal mucosal mitochondrial gene expression is associated with delayed gastric emptying in diabetic gastroenteropathy

Hindered by a limited understanding of the mechanisms responsible for diabetic gastroenteropathy (DGE), management is symptomatic. We investigated the duodenal mucosal expression of protein-coding genes and microRNAs (miRNA) in DGE and related them to clinical features. The diabetic phenotype, gastric emptying, mRNA, and miRNA expression and ultrastructure of duodenal mucosal biopsies were compared in 39 DGE patients and 21 controls. Among 3175 differentially expressed genes (FDR < 0.05), several mitochondrial DNA–encoded (mtDNA-encoded) genes (12 of 13 protein coding genes involved in oxidative phosphorylation [OXPHOS], both rRNAs and 9 of 22 transfer RNAs) were downregulated; conversely, nuclear DNA–encoded (nDNA-encoded) mitochondrial genes (OXPHOS) were upregulated in DGE. The promoters of differentially expressed genes were enriched in motifs for transcription factors (e.g., NRF1), which regulate mitochondrial biogenesis. Seventeen of 30 differentially expressed miRNAs targeted differentially expressed mitochondrial genes. Mitochondrial density was reduced and correlated with expression of 9 mtDNA OXPHOS genes. Uncovered by principal component (PC) analysis of 70 OXPHOS genes, PC1 was associated with neuropathy (P = 0.01) and delayed gastric emptying (P < 0.05). In DGE, mtDNA- and nDNA-encoded mitochondrial genes are reduced and increased — associated with reduced mitochondrial density, neuropathy, and delayed gastric emptying — and correlated with cognate miRNAs. These findings suggest that mitochondrial disturbances may contribute to delayed gastric emptying in DGE.

Expression of the regulated isoform of the electrogenic Na+/HCO3- cotransporter, NBCe1, is enriched in pacemaker interstitial cells of Cajal

Interstitial cells of Cajal (ICCs) generate electrical slow waves, which are required for normal gastrointestinal motility. The mechanisms for generation of normal pacemaking are not fully understood. Normal gastrointestinal contractility^- and electrical slow-wave activity depend on the presence of extracellular HCO₃^-. Previous transcriptional analysis identified enrichment of mRNA encoding the electrogenic Na⁺/HCO₃^- cotransporter (NBCe1) gene (Slc4a4) in pacemaker myenteric ICCs in mouse small intestine. We aimed to determine the distribution of NBCe1 protein in ICCs of the mouse gastrointestinal tract and to identify the transcripts of the Slc4a4 gene in mouse and human small intestinal tunica muscularis. We determined the distribution of NBCe1 immunoreactivity (NBCe1-IR) by immunofluorescent labeling in mouse and human tissues. In mice, NBCe1-IR was restricted to Kit-positive myenteric ICCs of the stomach and small intestine and submuscular ICCs of the large intestine, that is, the slow wave generating subset of ICCs. Other subtypes of ICCs were NBCe1-negative. Quantitative real-time PCR identified >500-fold enrichment of Slc4a4-207 and Slc4a4-208 transcripts ["IP3-receptor-binding protein released by IP3" (IRBIT)-regulated isoforms] in Kit-expressing cells isolated from Kit^creERT2/+, Rpl22^tm1.1Psam/Sj mice and from single GFP-positive ICCs from Kit^tm1Rosay mice. Human jejunal tunica muscularis ICCs were also NBCe1-positive, and SLC4A4-201 and SLC4A4-204 RNAs were >300-fold enriched relative to SLC4A4-202. In summary, NBCe1 protein expressed in ICCs with electrical pacemaker function is encoded by Slc4a4 gene transcripts that generate IRBIT-regulated isoforms of NBCe1. In conclusion, Na⁺/HCO₃^- cotransport through NBCe1 contributes to the generation of pacemaker activity in subsets of ICCs.NEW & NOTEWORTHY In this study, we show that the electrogenic Na+/HCO₃^- cotransporter, NBCe1/Slc4a4, is expressed in subtypes of interstitial cells of Cajal (ICCs) responsible for electrical slow wave generation throughout the mouse gastrointestinal tract and is absent in other types of ICCs. The transcripts of Slc4a4 expressed in mouse ICCs and human gastrointestinal smooth muscle are the regulated isoforms. This indicates a key role for HCO₃^- transport in generation of gastrointestinal motility patterns.

Avoidant/restrictive food intake disorder symptoms are frequent in patients presenting for symptoms of gastroparesis

INTRODUCTION

Patients with symptoms of gastroparesis/dyspepsia often avoid foods or restrict eating for symptom management. There is growing interest in understanding risk for feeding/eating disorders (FEDs) like avoidant/restrictive food intake disorder (ARFID). Among patients presenting with gastroparesis/dyspepsia symptoms, we aimed to determine: (a) FED symptom frequency, and (b) relation of FED symptoms to gastrointestinal symptom severity and gastric retention abnormalities.

METHODS

Adult patients (N = 288; 78% female) referred for gastroparesis/dyspepsia symptoms at two academic medical centers from January 2018-February 2019 completed self-report surveys for gastrointestinal symptom severity and FED symptoms. Gastric retention data were available for 210 patients, using 4-hour EggBeater gastric emptying scintigraphy (GES).

RESULTS

Clinically significant FED symptoms were present in 158 patients (54.9%). Interestingly, 115 patients (39.9%) met conservative self-report cutoff for ARFID symptoms, with 67 (23.3%) patients having documented psychosocial/medical impairment. Of those with survey data for other FEDs (n = 239), only 28 patients (11.7%) had restrictive eating disorders (anorexia nervosa; unspecified FED). Likelihood of having FED symptoms was significantly associated with greater gastroparesis symptom severity (OR = 2.23, P < .001), but not GES. In addition, gastroparesis symptom severity was moderately and significantly associated with greater ARFID symptom severity (b = 0.45, P < .001), but neither GES nor other FED symptoms.

DISCUSSION

In patients presenting with gastroparesis/dyspepsia symptoms, FED symptoms were frequent (55%), particularly ARFID, and were associated with greater gastrointestinal symptom severity, but not gastric retention. Gastroparesis/dyspepsia symptoms may mimic FEDs, particularly ARFID. Clinicians should be cautious about diagnosing ARFID in gastroparesis/dyspepsia patients, and screening for ARFID could assist behavioral treatment referral.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Intraoperative endoluminal pyloromyotomy as a novel approach to reduce delayed gastric emptying after pylorus-preserving pancreaticoduodenectomy-a retrospective study

Background

Delayed gastric emptying (DGE) is one of the most common complications after pylorus-preserving partial pancreaticoduodenectomy (ppPD). The aim of this retrospective study was to assess whether an intraoperative pyloromyotomy during ppPD prior to the creation of duodenojejunostomy reduces DGE.

Methods

Patients who underwent pylorus-preserving pancreaticoduodenectomy between January 2015 and December 2017 were divided into two groups on the basis of whether an intraoperative pyloromyotomy was performed (pyloromyotomy (PM) group) or not (no pyloromyotomy (NP) group). The primary endpoint was DGE according to the ISGPS definition. The confirmatory analysis of the primary endpoint was performed with multivariate analysis.

Results

One hundred and ten patients were included in the statistical analysis. Pyloromyotomy was performed in 44 of 110 (40%) cases. DGE of any grade was present in 62 patients (56.4%). The DGE rate was lower in the PM group (40.9%) compared with the NP group (66.7%), and pyloromyotomy was associated with a reduced risk for DGE in univariate (OR 0.35, 95% CI 0.16–0.76; P = 0.008) and multivariate analyses (OR 0.32, 95% CI 0.13–0.77; P = 0.011). The presence of an intra-abdominal complication was an independent risk factor for DGE in the multivariate analysis (OR 5.54, 95% CI 2.00–15.36; P = 0.001).

Conclusion

Intraoperative endoluminal pyloromyotomy during ppPD was associated with a reduced risk for DGE in this retrospective study. Pyloromyotomy should be considered a simple technique that can potentially reduce DGE rates after ppPD.

Inhibition of GSK-3β restores delayed gastric emptying in obesity-induced diabetic female mice

Diabetic gastroparesis (DG) is a clinical syndrome characterized by delayed gastric emptying (DGE). Loss of nuclear factor erythroid 2-related factor 2 (Nrf2) is associated with reduced neuronal nitric oxide synthase-α (nNOSα)-mediated gastric motility and DGE. Previous studies have shown that nuclear exclusion and inactivation of Nrf2 is partly regulated by glycogen synthase kinase 3β (GSK-3β). In the current study, the molecular signaling of GSK-3β-mediated Nrf2 activation and its mechanistic role on DG were investigated in high-fat diet (HFD)-induced obese/Type 2 diabetes (T2D) female mice. Adult female C57BL/6J mice were fed with HFD or normal diet (ND) with or without GSK-3β inhibitor (SB 216763, 10 mg/kg body wt ip) start from the 14th wk and continued feeding mice for an additional 3-wk time period. Our results show that treatment with GSK-3β inhibitor SB attenuated DGE in obese/T2D mice. Treatment with SB restored impaired gastric 1) Nrf2 and phase II antioxidant enzymes through PI3K/ERK/AKT-mediated pathway, 2) tetrahydrobiopterin (BH₄, cofactor of nNOS) biosynthesis enzyme dihydrofolate reductase, and 3) nNOSα dimerization in obese/T2 diabetic female mice. SB treatment normalized caspase 3 activity and downstream GSK-3β signaling in the gastric tissues of the obese/T2 diabetic female mice. In addition, GSK-3β inhibitor restored impaired nitrergic relaxation in hyperglycemic conditions. Finally, SB treatment reduced GSK3 marker, pTau in adult primary enteric neuronal cells. These findings emphasize the importance of GSK-3β on regulating gastric Nrf2 and nitrergic mediated gastric emptying in obese/diabetic rodents.NEW & NOTEWORTHY Inhibition of glycogen synthase kinase 3β (GSK-3β) with SB 216763 attenuates delayed gastric emptying through gastric nuclear factor erythroid 2-related factor 2 (Nrf2)-phase II enzymes in high-fat diet-fed female mice. SB 216763 restored impaired gastric PI3K/AKT/ β-catenin/caspase 3 expression. Inhibition of GSK-3β normalized gastric dihydrofolate reductase, neuronal nitric oxide synthase-α expression, dimerization and nitrergic relaxation. SB 216763 normalized both serum estrogen and nitrate levels in female obese/Type 2 diabetes mice. SB 216763 reduced downstream signaling of GSK-3β in enteric neuronal cells in vitro.

The Enteric Nervous System and Its Emerging Role as a Therapeutic Target

The gastrointestinal (GI) tract is innervated by the enteric nervous system (ENS), an extensive neuronal network that traverses along its walls. Due to local reflex circuits, the ENS is capable of functioning with and without input from the central nervous system. The functions of the ENS range from the propulsion of food to nutrient handling, blood flow regulation, and immunological defense. Records of it first being studied emerged in the early 19th century when the submucosal and myenteric plexuses were discovered. This was followed by extensive research and further delineation of its development, anatomy, and function during the next two centuries. The morbidity and mortality associated with the underdevelopment, infection, or inflammation of the ENS highlight its importance and the need for us to completely understand its normal function. This review will provide a general overview of the ENS to date and connect specific GI diseases including short bowel syndrome with neuronal pathophysiology and current therapies. Exciting opportunities in which the ENS could be used as a therapeutic target for common GI diseases will also be highlighted, as the further unlocking of such mechanisms could open the door to more therapy-related advances and ultimately change our treatment approach.

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

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

Gastroparesis: New insights into an old disease

Gastroparesis (Gp) is a chronic disease characterized by a delayed gastric emptying in the absence of mechanical obstruction. Although this condition has been reported in the literature since the mid-1900s, only recently has there been renewed clinical and scientific interest in this disease, which has a potentially great impact on the quality of life. The aim of this review is to explore the pathophysiological, diagnostic and therapeutical aspects of Gp according to the most recent evidence. A comprehensive online search for Gp was carried out using MEDLINE and EMBASE. Gp is the result of neuromuscular abnormalities of the gastric motor function. There is evidence that patients with idiopathic and diabetic Gp may display a reduction in nitrergic inhibitory neurons and in interstitial cells of Cajal and/or telocytes. As regards diagnostic approach, 99-Technetium scintigraphy is currently considered to be the gold standard for Gp. Its limits are a lack of standardization and a mild risk of radiation exposure. The C13 breath testing is a valid and safe alternative method. ¹³C acid octanoic and the ¹³C Spirulina platensis recently approved by the Food and Drug Administration are the most commonly used diagnostic kits. The wireless motility capsule is a promising technique, but its use is limited by costs and scarce availability in many countries. Finally, therapeutic strategies are related to the clinical severity of Gp. In mild and moderate Gp, dietary modification and prokinetic agents are generally sufficient. Metoclopramide is the only drug approved by the Food and Drug Administration for Gp. However, other older and new prokinetics and antiemetics can be considered. As a second-line therapy, tricyclic antidepressants and cannabinoids have been proposed. In severe cases the normal nutritional approach can be compromised and artificial nutrition may be needed. In drug-unresponsive Gp patients some alternative strategies (endoscopic, electric stimulation or surgery) are available.