Acotiamide improves stress-induced impaired gastric accommodation

Breaking Barriers in Functional Dyspepsia: A Systematic Review and Meta-analysis on Duodenal Tight Junction Protein Expression

Background/Aims

Disruptions in tight junction (TJ) protein expression leading to duodenal epithelial barrier impairment may contribute to increased intestinal permeability, potentially playing a role in functional dyspepsia (FD) pathophysiology. Currently published studies evaluated the role of several TJ proteins in FD patients with inconsistent results. Therefore, we conducted this systematic review and metaanalysis to evaluate the duodenal mucosal expression of several TJ proteins in FD.

Methods

We performed a systematic electronic search on PubMed, EMBASE, and Scopus using predefined keywords. Diagnosis of FD by Rome III or Rome IV criteria was considered acceptable. Full articles satisfying our inclusion and exclusion criteria were included. The principal summary outcome was the mean difference of several TJ proteins in FD patients and control subjects.

Results

A total of 8 and 5 studies were included in our qualitative and quantitative synthesis, respectively, with a total population of 666 participants, out of which 420 were FD patients. No significant differences were observed between FD patients and controls in the expression of claudin-1 (-0.102 [95% CI, -0.303, 0.099]), claudin-2 (0.161 [95% CI, -0.134, 0.456)], claudin-3 (0.278 [95% CI, -0.280, 0.837]), claudin-4 (0.045 [95% CI, -0.264, 0.354]), ZO-1 (-0.221 [95% CI, -0.683, 0.241]), ZO-2 (-0.070 [95% CI, -0.147, 0.007]), ZO-3 (-0.129 [95% CI, -0.376, 0.118]), β-catenin (-0.135 [95% CI, -0.484, 0.214]), E-cadherin (-0.083 [95% CI, -0.229, 0.063]), and occludin (-0.158 [95% CI, -0.409, 0.093]).

Conclusions

The expressions of all evaluated proteins including claudin-1, claudin-2, claudin-3, claudin-4, ZO-1, ZO-2, ZO-3, β-catenin, E-cadherin, and occludin did not significantly differ between FD patients and controls. However, due to the limited number of included studies, results should be interpreted with caution.

Effective Management of Chronic Intestinal Pseudo-Obstruction in MELAS Using Acotiamide: A Case Report

Introduction

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is reported to be a secondary cause of chronic intestinal pseudo-obstruction (CIPO). Although few case reports have described CIPO in MELAS, effective treatment for CIPO has not been established. Here, we present a case report of amelioration of CIPO symptoms using acotiamide in a patient with MELAS.

Case Presentation

A 51-year-old Japanese female with a mitochondrial disorder with m.3243A>G mutation and a history of anorexia for 2 years presented to our hospital with a left temporal headache and acute paraphasia. A stroke-like episode of MELAS was suspected and combined therapy with arginine, edaravone, and levetiracetam was initiated. Although her symptoms improved, she presented with nausea and vomiting and abdominal distension 6 days following admission. Abdominal contrast-enhanced computed tomography revealed dilatation from the stomach to the intestine, particularly marked the stomach, with neither obstruction nor impaired blood flow in the intestine. CIPO exacerbation with MELAS was suspected, and the patient's symptoms gradually improved with acotiamide.

Conclusion

Patients with MELAS could possibly experience stroke-like episodes during CIPO. Since acetylcholine possibly plays an important role in the pathophysiology of CIPO and acotiamide possesses prokinetic activity by inhibiting acetylcholinesterase, acotiamide could possibly improve CIPO symptoms.

A New Paradigm Shift in Gastroparesis Management

Gastroparesis, once regarded as a rare disease, is difficult to diagnose and challenging to treat; there were many breakthrough advances in the 2010s, shifting the paradigm of the understanding of this complex entity and its management. Similar to diabetes, its increasing prevalence reflects increased accessibility to diagnostic modalities and suggests that gastroparesis was underacknowledged in the past. Major developments in the three main aspects of the disease include the discovery of smooth muscle cells, interstitial cells of Cajal, PDGFRα+ cells syncytium, rather than interstitial cells of Cajal alone, as the main gastric pacemaker unit; the development of validated point-of-care diagnostic modalities such as a wireless motility capsule, the carbon 13-labeled breath test, and impedance planimetry; and the introduction of novel minimally invasive therapeutic options such as newer pharmacologic agents and gastric peroral endoscopic pyloromyotomy. All aspects of these advances will be discussed further in this review.

Gastric accommodation: Physiology, diagnostic modalities, clinical relevance, and therapies

BACKGROUND

Gastric accommodation is an essential gastric motor function which occurs following ingestion of a meal. Impaired gastric fundic accommodation (IFA) is associated with dyspeptic symptoms. Gastric accommodation is mediated by the vagal pathway with several important physiologic factors such as duodenal nutrient feedback playing a significant role. IFA has been described as a pathophysiologic factor in several gastrointestinal disorders including functional dyspepsia, diabetic gastropathy, post-Nissen fundoplication, postsurgical gastrectomy, and rumination syndrome. Modalities for gastric accommodation assessment include gastric barostat, intragastric meal distribution via scintigraphy, drinking tests (eg, water load), SPECT, MRI, 2D and 3D ultrasound, and intragastric high-resolution manometry. Several treatment options including sumatriptan, buspirone, tandospirone, ondansetron, and acotiamide may improve symptoms by increasing post-meal gastric volume.

PURPOSE

Our aim is to provide an overview of the physiology, diagnostic modalities, and therapies for IFA. A literature search was conducted on PubMed, Google Scholar, and other sources to identify relevant studies available until December 2020. Gastric accommodation is an important gastric motor function which if impaired, is associated with several upper gastrointestinal disorders. There are an increasing number of gastric accommodation testing modalities; however, each has facets which warrant consideration. Evidence regarding potentially effective therapies for IFA is growing.

Evaluation of gastric emptying in patients with gastroparesis by three-dimensional ultrasound

Background

To diagnose gastroparesis, it is necessary to assess gastric emptying accurately. This study aims to investigate the role of three-dimensional ultrasonography (3-D US) on the measurement of gastric volume to evaluate gastric accommodation in healthy patients.

Methods

In this study, 21 volunteers, 46 patients with diabetic gastroparesis (DG), and 22 patients with postsurgical gastroparesis (PSG) underwent 3-D US after oral administration of 250 mL gastrointestinal contrast at 2, 30, 60, and 90 min. The volume of the contrast agent in the stomach was then calculated using the virtual organ computer-aided analysis (VOCAL) (Virtual Organ Computer-aided AnaLysis, General Electric Medical Systems, Kretztechnik, Zipf, Austria).

Results

In the DG group, the gastric residue volumes at postprandial 60 and 90 min were significantly higher than those in the healthy group (P<0.05), and the areas under the receiver operating characteristic (ROC) curve of these parameters were 0.830 and 0.957, respectively. There were significant differences between the PSG and healthy groups at 60 and 90 min; however, the AUC of gastric residue at 90 min (0.955) was higher than the AUC at 60 min (0.697).

Conclusions

Therefore, this study showed that the 3-D US is a powerful tool for assessing gastric emptying and provides a new strategy for diagnosing gastroparesis.

L-Glutamine and Physical Exercise Prevent Intestinal Inflammation and Oxidative Stress Without Improving Gastric Dysmotility in Rats with Ulcerative Colitis

The aim of this study was to evaluate the effects of glutamine supplementation or exercise on gastric emptying and intestinal inflammation in rats with ulcerative colitis (UC). Strength exercise consisted of jump training 4 × 10 repetitions/5 days a week/8 weeks with progressive overload. Endurance exercise consisted of swimming without overload for a period of 1 h a day/5 days a week/8 weeks. Another group (sedentary) of animals was supplemented with L-glutamine (1 g/kg of body weight) orally for 8 weeks before induction of UC. Colitis was induced by intra-colonic administration of 1 mL of 4% acetic acid. We assessed gastric emptying, macroscopic and microscopic scoring, oxidative stress markers, and IL-1β, IL-6, and (TNF-α) levels. The UC significantly increased (p < 0.05) the gastric emptying compared with the saline control group. We observed a significantly decrease (p < 0.05) in body weight gain in UC rats compared with the control groups. Both exercise interventions and L-glutamine supplementation significantly prevented (p < 0.05) weight loss compared with the UC group. Strength and endurance exercises significantly prevented (p < 0.05) the increase of microscopic scores and oxidative stress (p < 0.05). L-glutamine supplementation in UC rats prevented hemorrhagic damage and improved oxidative stress markers (p < 0.05). Strength and endurance exercises and glutamine decreased the concentrations of inflammatory cytokines IL-1β, IL-6, and TNF-α compared with the UC group (p < 0.05). Strength and endurance exercises and L-glutamine supplementation prevented intestinal inflammation and improved cytokines and oxidative stress levels without altering gastric dysmotility in rats with UC.

Patients with dyspepsia have impaired mucosal integrity both in the duodenum and jejunum: in vivo assessment of small bowel mucosal integrity using baseline impedance

BACKGROUND

Recent studies reported that impaired proximal duodenal mucosa, assessed by duodenal biopsy, could play an important role in the development of dyspeptic symptoms. The aims of this study were (a) to develop a method to measure "in vivo" duodenal and jejunal baseline impedance (BI) and (b) to assess small bowel mucosal integrity in patients with functional dyspepsia (FD) and healthy controls (HC).

METHODS

We recruited 16 patients with FD and 15 HC. All subjects underwent ambulatory duodeno-jejunal manometry combined with impedance (HRM/Z), BI were determined by measuring impedance immediately after the passage of nocturnal migrating motor complex (MMC) phase IIIs.

RESULTS

The number of MMC phase IIIs in FD was significantly lower than that in HC (2.6 ± 1.4 vs 4.8 ± 1.7, p < 0.001). The BI in patients was significantly lower than that in HC in D1(164.2 ± 59.8 Ω in FD and 243.1 ± 40.5 Ω in HC, p = 0.0061), D2 (191.2 ± 34.1 and 256.5 ± 91.4 Ω, p = 0.01), D3 (214.0 ± 76.9 and 278.1 ± 45.3 Ω, p = 0.009), D4 (270.8 ± 54.2 and 351.8 ± 50.2 Ω, p < 0.001), and J1 (312.2 ± 55.4 and 379.3 ± 38.3 Ω, p = 0.001).

CONCLUSIONS

This is the first study reporting the duodenal and jejunal BI in vivo. The results have shown significantly lowered BI in the proximal small intestine in patients with FD compared to HC. Furthermore it suggests that measurements of small bowel BI could be used as a biomarker for diagnosis and follow up of patients with FD.

Duodenal low-grade inflammation and expression of tight junction proteins in functional dyspepsia

BACKGROUND

Duodenal changes in functional dyspepsia (FD) might be related to the development of symptoms. However, relationships among low-grade inflammation, Helicobacter pylori infection, and protein expression by tight junctions (TJs) in the duodenum are unclear. We therefore aimed to determine whether duodenal inflammation and genes associated with TJ proteins are associated with FD.

METHODS

We evaluated inflammatory cell infiltration of the duodenum, H pylori infection, and genes associated with TJ proteins in duodenal biopsy specimens from 35 patients with FD according to the Rome III diagnostic questionnaire and from 31 asymptomatic controls without structural diseases. We immunohistochemically detected eosinophils and mast cells and counted them. The expression of claudins, occludin, and zonula occludens (ZO)-1 mRNA was evaluated using quantitative RT-PCR. Infection with H pylori was determined by measuring serum antibodies, rapid urease or urea breath tests, and endoscopic findings.

RESULTS

Sex, age, and H pyloriinfection rates did not differ between patients with FD and controls. The numbers of eosinophils and mast cells were significantly increased in patients with FD compared with controls and were significantly correlated. Inflammatory cell counts in the duodenum were not associated with H pylori infection status. Claudin-3 mRNA expression was increased in the patients with FD.

CONCLUSIONS

Subtle inflammation identified in the duodenum of patients with FD might be associated with the onset and persistence of dyspeptic symptoms.

Review article: treatment options for functional dyspepsia

BACKGROUND

Functional dyspepsia, consisting of epigastric pain syndrome and postprandial distress syndrome, is a prevalent functional gastrointestinal disorder. To date, only limited treatment options are available and conflicting results in terms of efficacy have been reported. Consequently, nonpharmacological treatment options are increasingly being explored for functional dyspepsia.

AIM

To provide an overview of current pharmacological and nonpharmacological treatment options for functional dyspepsia.

METHODS

A literature search was conducted on Pubmed and other sources to identify relevant studies.

RESULTS

Acid suppressive therapy reduced symptoms in 30%-70% of the patients, with higher benefit in epigastric pain syndrome and superior effectiveness for proton pump inhibitors compared to H₂ -antagonists. Prokinetic agents, primarily used to treat postprandial distress syndrome, showed variable efficiency: 59%-81% responder rate for dopamine receptor antagonists, 32%-91% for serotonin-4-receptor agonists and 31%-80% for muscarinic receptor antagonists. H Pylori eradication, recommended in infected patients, was effective in 24%-82%. Refractory symptoms are addressed with neuromodulators. However, their efficacy in functional dyspepsia remains incompletely elucidated, available data showing symptom reduction in 27%-71% of the patients. Regarding herbal agents, peppermint oil reduced symptoms in 66%-91%, rikkunshito in 29%-34% and iberogast in 20%-95%. Lastly, acupuncture, cognitive behavioural therapy and hypnotherapy may help to provide symptom control, but research on their efficacy remains sparse.

CONCLUSIONS

None of the available therapies is effective in the majority of patients without being associated with major side effects. Developing new treatment options is challenging due to the heterogeneity of functional dyspepsia, the lack of readily identified target mechanisms and the poor association between pathophysiological disturbances and symptoms.

Role of Bitter Taste Receptors in Regulating Gastric Accommodation in Guinea Pigs

Taste stimulants play important roles in triggering digestion and absorption of nutrients and in toxin detection, under the control of the gut-brain axis. Bitter compounds regulate gut hormone secretion and gastrointestinal motility through bitter taste receptors (TAS2Rs) located in the taste buds on the tongue and in the enteroendocrine cells. Gastric accommodation (GA) is an important physiologic function. However, the role of TAS2R agonists in regulating GA remains unclear. To clarify whether GA is influenced by bitter stimulants, we examined the effect of TAS2R agonist denatonium benzoate (DB), administered intraorally and intragastrically, by measuring the consequent intrabag pressure in the proximal stomach of guinea pigs. Effects of the Kampo medicine rikkunshito (RKT) and its bitter components liquiritigenin and naringenin on GA were also examined. Intraoral DB (0.2 nmol/ml) administration enhanced GA. Intragastric DB administration (0.1 and 1 nmol/kg) promoted GA, whereas higher DB doses (30 μmol/kg) inhibited it. Similar changes in GA were observed with intragastric (1000 mg/kg) and intraoral (200 mg/ml) RKT administration. Liquiritigenin and naringenin also promoted GA. These findings suggest that GA is affected by the stimulation of TAS2Rs in the oral cavity or gut in guinea pigs.

Acotiamide affects antral motility, but has no effect on fundic motility, gastric emptying or symptom perception in healthy participants

BACKGROUND

Acotiamide, a prokinetic agent was shown to be efficacious in the treatment of functional dyspepsia (FD). The exact mechanism of action is incompletely elucidated.

METHODS

This randomized, placebo-controlled, cross-over study aimed to examine the effect of acotiamide on gastric motility, measured as intragastric pressure, gastric emptying (GE) rate and gastrointestinal (GI) symptom perception in healthy volunteers (HVs). Participants were treated with acotiamide (100 mg tid) and placebo for 3 weeks, separated by a 1-week washout period. A daily symptom diary was collected during both treatments. At the end of each treatment period, GE rate and gastric motility were assessed with a ¹³ C-octanoic acid breath test and high-resolution manometry during nutrient infusion, respectively. GI symptom levels were scored during high-resolution manometry. Data were analyzed using mixed models. The study was registered as NCT03402984.

KEY RESULTS

Twenty HVs (10 female, 25 ± 4.1 years, 22.58 ± 2.73 kg/m² ) participated in the study. There was no difference in GE half time between both treatments (P = 0.92). Acotiamide had no effect on fundic pressures before and after nutrient infusion (P = 0.91). However, postprandial antral pressures remained significantly lower compared to placebo (P = 0.015). There was no significant difference in hunger, satiation and GI symptoms scores assessed during IGP measurement and by the daily diary (P > 0.12 for all).

CONCLUSION

Acotiamide is associated with lower antral pressures after nutrient intake, whereas it has no effect on fundic pressures, GE rate and symptom perceptions in HVs. Studies in FD need to elucidate whether lower antral pressures induced by acotiamide underlie postprandial symptom improvement in FD.

Management of functional dyspepsia: state of the art and emerging therapies

Patients with functional dyspepsia, defined in the 2016 Rome IV criteria as bothersome clinical dyspepsia symptoms, experience markedly reduced quality of life. Several etiologies have been associated with the disorder. In the Rome IV criteria, the brain-gut axis was acknowledged as an important factor in the etiology of functional gastrointestinal (GI) disorders. The distinct subgroups of functional dyspepsia, epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS), are treated differently: acid secretion inhibitors are recommended with patients with EPS, whereas prokinetic drugs as mosapride and acotiamide are recommended for patients with PDS. A previous study has reported that proton pump inhibitors (PPIs) and H₂-blockers were equally effective in functional dyspepsia. A new drug, acotiamide, a muscarinic antagonist and cholinesterase inhibitor, has been shown to improve gastric motility in rodents and dogs, and to reduce PDS symptoms in patients in double-blind multicenter studies. The pharmacological mechanisms of acotiamide remain unknown; whether acotiamide alters gastric emptying and gastric accommodation in patients with functional dyspepsia remains an open question. Other emerging treatment options include Rikkunshito, a herbal medicine that improves gastric emptying through 5-hydroxytryptamine (5-HT)2B-mediated pharmacological action, and tricyclic antidepressants (TCAs). Different drugs are needed to accommodate the clinical symptoms and etiology in individual patients.