Why dyspepsia can occur without organic disease: pathogenesis and management of functional dyspepsia

Efficacy and safety of the herbal formula Naesohwajung-tang for functional dyspepsia: a randomized, double-blind, placebo-controlled, multi-center trial

Background: Current treatment and management options for functional dyspepsia (FD) often fail to alleviate symptoms. Naesohwajung-tang (NHT) is a herbal formula frequently used to treat functional dyspepsia in traditional Korean medicine. However, few animal and case reports on the use of Naesohwajung-tang for functional dyspepsia treatment exist, and the clinical evidence remains deficient. Objectives: This study aimed to evaluate the efficacy of Naesohwajung-tang in patients with functional dyspepsia. Methods: We enrolled 116 patients with functional dyspepsia at two study sites in this 4 weeks, randomized, double-blind, placebo-controlled trial and randomly assigned them to either the Naesohwajung-tang or placebo group. To evaluate the efficacy of Naesohwajung-tang, the primary endpoint was a score on the total dyspepsia symptom (TDS) scale after treatment. The overall treatment effect (OTE), single dyspepsia symptom (SDS) scale, food retention questionnaire (FRQ), Damum questionnaire (DQ), functional dyspepsia-related quality of life (FD-QoL) questionnaire, and gastric myoelectrical activity measured using electrogastrography were evaluated as secondary outcomes. Laboratory tests were performed to confirm the safety of the intervention. Results: The 4 weeks administration of Naesohwajung-tang granules demonstrated a significantly higher reduction in the total dyspepsia symptom (p < 0.05) and a higher degree of improvement in the total dyspepsia symptom (p < 0.01) than the placebo group. Patients who underwent Naesohwajung-tang had a significantly higher overall treatment effect and a greater increase in the degree of improvement in scores such as epigastric burning, postprandial fullness, early satiation, functional dyspepsia-related quality of life, and Damum questionnaire (p < 0.05). Additionally, the Naesohwajung-tang group showed a greater effect in preventing a decrease in the percentage of normal gastric slow waves after meals than the placebo group. As a result of subgroup analyses using the degree of improvement in total dyspepsia symptom, Naesohwajung-tang was found to be more effective than placebo in female, younger patients (<65 years), with a high body-mass index (≥22), overlap type, food retention type, and Dampness and heat in the spleen and stomach systems pattern. There was no significant difference in the incidence of adverse events between the two groups. Conclusion: This is the first randomized clinical trial to verify that Naesohwajung-tang leads on symptom relief in patients with functional dyspepsia. Clinical Trial Registration: https://cris.nih.go.kr/cris/search/detailSearch.do/17613, identifier KCT0003405.

Aqueous Extract of Phyllanthus emblica L. Alleviates Functional Dyspepsia through Regulating Gastrointestinal Hormones and Gut Microbiome In Vivo

Phyllanthus emblica L. fruits were extracted by a hot water assistant with ultrasonication to obtain aqueous Phyllanthus emblica L. extract (APE). The ameliorating functional dyspepsia (FD) effect of a low dose (150 mg/kg) and a high dose (300 mg/kg) of APE was exhibited by determining the gastrointestinal motility, gastrointestinal hormones, and gut microbiome shifts in reserpine induced FD male balb/c mice. APE increased the gastrointestinal motility including the gastric emptying (GE) rate and small intestinal transit (SIT) rate. The level of serum gastrointestinal hormones such as motilin (MTL) and gastrin (GAS) increased, and the vasoactive intestinal peptide (VIP) level decreased after the administration of APE. Furthermore, the gut microbiome analysis demonstrated that APE could regulate the microbiome structure and restore homeostasis by elevating useful bacterial abundance, while simultaneously decreasing harmful bacterial abundance. This study demonstrated the ameliorating FD effect of APE and its potential efficacy in curing functional gastrointestinal disorders and maintaining a healthy digestive tract.

Yokukansan Suppresses Gastric Hypersensitivity and Eosinophil-associated Microinflammation in Rats With Functional Dyspepsia

Background/Aims

Herbal medicine is an important complementary therapy for functional dyspepsia (FD). However, its effect against gastric hypersensitivity in patients with FD has rarely been evaluated. Yokukansan (YKS), a traditional Japanese herbal medicine, is effective against neuropathic and inflammatory pain. This study aims to use a maternal separation (MS) stress-induced FD model to investigate the effects of YKS against gastric hypersensitivity, gastric motility, and duodenal micro-inflammation.

Methods

The MS stress model was established by separating newborn Sprague-Dawley rats from their mothers for 2 hours a day from postnatal days 1 to 10. At the age of 7-8 weeks, the rats were treated with YKS at a dose of 5 mL/kg (1 g/kg) for 7 consecutive days. After YKS treatment, electromyographic activity in the acromiotrapezius muscle by gastric distention and the gastric-emptying rate were assessed. Immunohistochemical analysis of eosinophils in the duodenum and phosphorylated extracellular signal-regulated kinase (p-ERK) 1/2 in the spinal cord was performed.

Results

YKS treatment suppressed MS stress-induced gastric hypersensitivity and decreased the elevated levels of p-ERK1/2 in the spinal cord. In the gastroduodenal tract, YKS inhibited eosinophil-associated micro-inflammation but did not improve gastric dysmotility.

Conclusions

YKS treatment improved gastric hypersensitivity by alleviating eosinophil-associated micro-inflammation in the gastroduodenal tract. This treatment may be considered an effective therapeutic option for epigastric pain and micro-inflammation in patients with FD.

Functional dyspepsia: a multifaceted problem in gastroenterology

The article presents the views on dyspepsia in world practice, data on the difficulties of diagnosis and the problem of the effectiveness of various therapy regimens. Particular attention is paid to the use of fixed forms of drugs for functional dyspepsia, in particular Omez DSR.

Frequency and risk factors of non-alcoholic fatty liver disease in Helicobacter pylori-infected dyspeptic patients: A cross-sectional study

Background

In dyspeptic patients with Helicobacter pylori contributes to non-alcoholic fatty liver disease. However, little evidence available from Pakistan.

Objective

The study aims to determine the frequency and risk factors of non-alcoholic fatty liver disease in dyspeptic patients with Helicobacter pylori.

Methods

This cross-sectional study was conducted between 22 November 2016 and 30 June 2018. Adults of age between 18 and 90 years who attended the out-patient department due to abdominal discomfort, pain, fullness, and bloating who underwent upper gastrointestinal tract endoscopy were enrolled after taking informed consent. Patients with celiac disease, inflammatory bowel disease, taking alcohol, pregnant women and lactating mothers, known cases of hepatitis B and C, and history of recent antibiotic use were excluded. Data on age, gender, smoking, alcohol use, dyslipidemia, hypertension, type 2 diabetes mellitus, and ischemic heart disease were collected. Non-alcoholic fatty liver disease was diagnosed through ultrasonography. Helicobacter pylori infection was detected using a carbon urea breath test.

Results

A total of 698 patients were screened for eligibility, and 399 (57.2%) had Helicobacter pylori infection and were enrolled in the study after consent. The median age was 50.1 (interquartile range = 14.5) years and 209 (52.4%) were males. Frequency of non-alcoholic fatty liver disease in patients with Helicobacter pylori dyspeptic patients was 153 (38.3%). Factors associated with non-alcoholic fatty liver disease in the presence of Helicobacter pylori were dyslipidemia 7.38 (95% confidence interval = 2.4-22.71), type 2 diabetes mellitus 5.96 (95% confidence interval = 1.86-19.07), hypertension 3.0 (95% confidence interval = 1.21-7.45), and moderate gastritis 2.81 (95% confidence interval = 1.2-6.59).

Conclusion

The frequency of non-alcoholic fatty liver disease in Helicobacter Pylori dyspeptic patients was 38.3%. Male gender, dyslipidemia, hypertension, ischemic heart disease, and moderate gastritis were associated with non-alcoholic fatty liver disease.

Upper gastrointestinal endoscopy; A study from a rural population of Sindh, Pakistan

Objective:

To discuss common indications and findings on upper gastrointestinal endoscopy as well as to correlate these findings with alarm symptoms in the rural population of Gadap town, Sindh.

Methods:

This was a retrospective study on 1288 patients conducted in the medical ward of Fatima Hospital, Baqai Medical University. Patients’ demographics and other data related to the procedure were recovered from patients’ records. SPSS version 20 was used for statistical analysis.

Results:

Ratio of male and female patients was approximately 1:1. Majority of the patients were young, and most procedures were done as outpatients without the requirement of conscious sedation. Epigastric pain was the primary indication for upper GI endoscopy (62.6%). One third of the procedures performed did not report any pathological finding. Probability of a positive finding was more likely if a patient presented with dysphagia, heart-burn, hematemesis, vomiting, or for screening endoscopy (for varices). Patients who were diagnosed with esophageal candidiasis, esophageal varices or esophageal growth/ ulcer had reported one or more alarm symptoms in their history.

Conclusions:

Upper gastrointestinal endoscopy is a useful test to diagnose disorders of the esophagus, stomach and duodenum. However, it is an expensive procedure and therefore referring physicians should keep appropriate clinical indication and ethical considerations in mind before recommending such an investigation to their patients.

Effect of Massa Medicata Fermentata on the Gut Microbiota of Dyspepsia Mice Based on 16S rRNA Technique

Massa Medicata Fermentata (MMF) is a traditional Chinese medicine (TCM) for treating indigestion and its related disorders. This study analyzes the effect of MMF on intestinal microorganisms in dyspepsia mice based on 16S rRNA technology. We take a dyspepsia model caused by a high-protein, high-calorie, high-fat diet. The 60 specific-pathogen free Kunming (SPF KM) mice were randomly divided into a model group (n=12), an MMF group (LSQ group, n=12), a Jianweixiaoshi group (JWXS group, n=12), a domperidone group (DP group, n=12), and a blank group (n=12). On the seventh day of administration, mice were fasted and deprived of water. After 24 h, take the second feces of stress defecation in mice under strict aseptic conditions and quickly transfer them to a sterile cryotube. This study comprehensively evaluates the α-diversity, β-diversity, flora abundance and composition of each group of mice's intestinal microorganisms, and their correlation with functional dyspepsia based on the 16S rRNA gene sequencing technology. After modeling, some dyspepsia reactions, proximal gastric relaxation reduction, and intestinal microflora changes were noted. Dyspepsia mice showed dyspepsia reactions and proximal gastric relaxation reduction, characterized by a significant decrease of contents of gastrin (P < 0.01) and cholinesterase (P < 0.01). MMF can improve dyspepsia symptoms and promote proximal gastric relaxation. Significant intestinal flora disorders were found in dyspepsia mice, including downregulation of Bacteroidetes, Lactobacillus, and Prevotellaceae and upregulation of Proteobacteria, Verrucomicrobia, Epsilonbacteraeota, Firmicutes, Lachnospiraceae NK4A136 group, and Lachnospiraceae. MMF could alleviate intestinal microflora disturbance, and the regulation effect of MMF on Bacteroidetes, Verrucomicrobia, and Epsilonbacteraeota was more reliable than that of Jianweixiaoshi tables and domperidone. The intestinal microflora may be correlated with the promoted digestion of MMF.

[Functional diseases of the gastrointestinal tract in the context with overlapping functional disorders: current status of the problem]

Functional diseases of the gastrointestinal tract cause significant damage to the health care system. Their frequent combination in the same patient with the migration of clinical symptoms throughout the digestive tube is accompanied by continuous exacerbations, refractory to the therapy and severe psychosocial disorders. This review provides data on the main etiopathogenetic factors, clinical manifestations, course features and management tactics for patients with overlapping for the most common functional diseases of the gastrointestinal tract.

Recent understanding of the pathophysiology of functional dyspepsia: role of the duodenum as the pathogenic center

Over almost 30 years since functional dyspepsia (FD) was defined, researchers have endeavored to elucidate the pathophysiology of functional gastrointestinal disorders. Now a consensus is emerging that the gastric symptoms of FD are caused mainly by gastric motility abnormalities and gastric hypersensitivity. The involvement of other causative factors including acid, Helicobacter pylori, psychological factors, and diet has been debated, but how they are involved in the manifestation of dyspeptic symptoms remains unclear. We believe that most of those factors cause FD symptoms by inducing gastric motility abnormalities and gastric hypersensitivity via the duodenum. Here, we discuss 2 possible reasons why patients with FD experience chronic upper abdominal symptoms: (1) the possibility that the contents of the duodenum of patients with FD differ from those of healthy persons and the different contents stimulate the duodenum, and (2) the possibility that the duodenum of patients with FD is more sensitive to noxious stimuli because of low-grade inflammation and increased mucosal permeability.

Ethnic/racial differences in gastrointestinal symptoms and diagnosis associated with the risk of Helicobacter pylori infection in the US

Background

In the US, neither the prevalence nor the gastrointestinal (GI) diagnosis/symptoms associated with Helicobacter pylori (HP) have been examined in different racial/ethnic groups.

Aim

To determine the racial/ethnic differences in HP infection associated with GI diagnoses/symptoms using the Cerner Health Facts^® database.

Methods

This cross-sectional study collected data during the period of 2000–2015 from the following ethnic/racial groups: 8,236,317 white, 2,085,389 black, 426,622 Hispanic, 293,156 Asian Pacific/Islander (APIs), and 89,179 Native American/Alaskan Native (NA/AN) patients aged 21–65 years old; the data were then analyzed. The primary dependent variable was a diagnosis of HP (ICD-9-Clinical Modification/ICD-10 classification). SAS version 9.4 was used for the statistical analysis. The statistical analysis was performed on 11,130,663 patients with GI symptoms, and of these, 152,086 patients were positive for the infection.

Results

Hispanics and NA/ANs had the highest prevalence of HP associated with upper GI symptoms/diagnosis. Nevertheless, blacks and APIs presented the highest relative risk (RR) of HP associated with dyspepsia (RR [95% CI] =11.2 [10.7–11.9] and 14.2 [12.8–15.6]), peptic ulcer (RR =13.8 [13.3–14.5] and 10.7 [9.3–12.3]), and atrophic gastritis (RR =9 [8.5–9.6] and 7.4 [6.4–8.5]), respectively. In all racial/ethnic groups, HP was also associated with inflammatory bowel diseases, liver diseases, and celiac diseases.

Conclusion

Black and API populations had the highest risk of HP associated with upper GI symptoms/diagnosis. Black patients also had the highest risk for HP associated with GI cancer.

Higher frequency of upper gastrointestinal symptoms in healthy young Japanese females compared to males and older generations

BACKGROUND

The aim of this study was to evaluate the differences in upper gastrointestinal symptoms between generations and genders in relatively healthy Japanese subjects.

METHODS

Altogether, 4086 healthy Japanese male and female (M/F) adults (M/F: 2244/1842) were analyzed. Among them, 3505 subjects (M/F: 1922/1583) were underwent a routine medical checkup at one of five hospitals in Saga, Japan from January 2013 to December 2013. The others were 581 (M/F: 322/259) healthy young volunteers at the Saga Medical School from April 2007 to March 2013. The participants were asked to complete the frequency scale for the symptoms of gastroesophageal reflex disease (FSSG) questionnaire, undergo upper gastrointestinal endoscopy, and submit to a rapid urease test to diagnose Helicobacter pylori infection. Among the 4086 subjects, the 2414 who had no H. pylori infection and no positive endoscopic findings were enrolled in the study.

RESULTS

Subjects' average age was 46.9 ± 12.2 years, with males' and females' ages being almost equivalent. The total FSSG score were high in females compared to males (P < 0.01) and decreased significantly with aging (P < 0.05). Among the generations, FSSG scores were the highest for those 20-29 years old, and they were significantly decreased with ageing in both males and females (P < 0.05).

CONCLUSION

The FSSG score was significantly higher in healthy Japanese females than in males, and the scores decreased with aging.

A randomized placebo-controlled trial on the effects of Menthacarin, a proprietary peppermint- and caraway-oil-preparation, on symptoms and quality of life in patients with functional dyspepsia

BACKGROUND

Functional dyspepsia (FD) is a very common condition affecting more than 10% of the population. While there is no cure, a few drugs have been found to be effective for the relief of symptoms, although most are only effective in a subgroup of patients. We assess and compare the efficacy of a fixed peppermint/caraway-oil-combination (Menthacarin) on symptoms and quality of life (QoL) in patients with FD symptoms consistent with epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS).

METHODS

In a prospective, double-blind, multicenter trial, 114 outpatients with chronic or recurrent FD were randomized and treated for 4 weeks with the proprietary peppermint- and caraway-oil-preparation Menthacarin or placebo (2×1 capsule/day). Improvement of abdominal pain and discomfort were used as co-primary efficacy measures (scores measured with the validated Nepean Dyspepsia Index).

KEY RESULTS

After 2 and 4 weeks, active treatment was superior to placebo in alleviating symptoms consistent with PDS and EPS (P all <.001). After 4 weeks of treatment, pain and discomfort scores improved by 7.6±4.8 and 3.6±2.5 points (full analysis set; mean±SD) for Menthacarin and by 3.4±4.3 and 1.3±2.1 points for placebo, respectively. All secondary efficacy measures showed advantages for Menthacarin.

CONCLUSIONS & INFERENCES

Menthacarin is an effective therapy for the relief of pain and discomfort and improvement of disease-specific QoL in patients with FD and significantly improves symptoms consistent with EPS and PDS.

Genetic variants of immune-related genes IL17F and IL10 are associated with functional dyspepsia: A case-control study

BACKGROUND

Low-grade inflammation may play an important role in pathogenesis of functional dyspepsia (FD). Since cytokines may influence gastric mucosal inflammation, which is associated with FD, we evaluated singe nucleotide polymorphisms (SNPs) of pro-inflammatory IL17F and anti-inflammatory IL10 cytokine genes in patients with FD and healthy subjects (HS).

METHODS

Two hundred and thirty-seven consecutive patients with FD (Rome III) and 250 HS were genotyped for IL17F (rs2397084: A/G, rs763780: T/C) and IL10 (rs1800896: G/A, rs1800871: C/T) (PCR-RFLP).

RESULTS

Patients with FD [173 (73%) men, age 38.4±12 years] were comparable with HS [195 (78%) men, age 37.3±12 years] with respect to age and gender. Out of 237 patients, 26 (11%) had epigastric pain, 55 (23.2%) had post-prandial distress syndromes (EPS, PDS), and 156 (65.8%) had EPS-PDS overlap. Among 237 patients with FD, GG (variant) genotype of IL17F (rs2397084) was more common than HS [15 (6.3%) vs. 4 (1.6%), p=0.015, odds ratio (OR)=4.0, 95% confidence interval (CI)=1.3-12.3]. IL17F (rs763780) and IL10 (rs1800896) were comparable among patients and HS (p=0.56, 0.28), respectively. However, TT (variant) genotype of IL10 (rs1800871) was more common among patients than HS [39 (16.5%) vs. 32 (12.8%), p=0.06, OR=1.7, 95% CI=0.98-2.98]. SNPs of IL17F and IL10 (rs2397084, rs763780, rs1800896 and rs1800871) were comparable among patients among sub-types of FD (p=0.80 and 0.44).

CONCLUSION

SNPs of IL17F (rs2397084) and IL10 (rs1800871) genes are associated with FD.

Helicobacter pylori infection status had no influence on upper gastrointestinal symptoms: a cross-sectional analysis of 3,005 Japanese subjects without upper gastrointestinal lesions undergoing medical health checkups

BACKGROUND

This study aimed to evaluate the influence of Helicobacter pylori infection and its eradication on the upper gastrointestinal symptoms of relatively healthy Japanese subjects.

METHODS

A total of 3,005 subjects (male/female: 1,549/1,456) undergoing medical health checkups were enrolled in the present study, at five hospitals in Saga, Japan, from January to December 2013. They had no significant findings following upper gastrointestinal endoscopy. All subjects completed a questionnaire that addressed a frequency scale for symptoms of gastroesophageal reflux disease. The questionnaire comprised seven questions regarding reflux symptoms and seven regarding acid-related dyspepsia, which were answered with a score based on the frequency of symptoms. Helicobacter pylori infection was identified by a rapid urease test and/or H. pylori antibody titer, and an eradication history was confirmed by the subjects' medical records.

RESULTS

Helicobacter pylori infection was positive in 894 subjects out of 3,005 (29.8%). Eradication of Helicobacter pylori was successfully achieved in 440 subjects of 458 treated. Helicobacter pylori infection had no influence on the acid-related dyspepsia evaluated by the questionnaire, whereas the mean reflux score was relatively high in the Helicobacter pylori native negative subjects compared to Helicobacter pylori native positive. Eradication of Helicobacter pylori and time span after the eradication had no effect on the upper gastrointestinal symptoms evaluated by the questionnaire.

CONCLUSION

Helicobacter pylori infection and history of eradication did not affect acid-related dyspepsia symptoms in Japanese healthy subjects.

Impaired Interoception in a Preclinical Model of Functional Dyspepsia

INTRODUCTION

The etiologies of functional dyspepsia symptoms, including postprandial distress syndrome, remain unknown. We tested the hypothesis that neonatal colon inflammation induces postprandial distress syndrome-like symptoms in adult life that associate with increased activation of vagal afferent pathways and forebrain limbic regions.

RESULTS

These rats showed a significant decrease in nutrient meal consumption to satiety after an overnight fast, decrease in gastric emptying, decrease in total distance traveled, and decrease in percent distance traveled in midfield versus control rats in open field test, indicating postprandial anxiety- and depression-like behaviors. Adult naïve rats treated with oral iodoacetamide to induce H. pylori-like mild gastritis demonstrated similar postprandial effects as the above rats.

CONCLUSIONS

We concluded that neonatal colon inflammation is a risk factor for the development of postprandial distress syndrome-like symptoms. While mild gastritis can induce symptoms similar to those of neonatal colon inflammation, gastritis in these rats does not worsen the symptoms.

Effect of Pixu 1 recipe on isocitrate dehydrogenase expression in liver tissue of functional dyspepsia rats with spleen deficiency

AIM

To investigate the expression of isocitrate dehydrogenase (IDH) protein and mRNA in liver tissue of functional dyspepsia (FD) rats with spleen deficiency after intervention with Pixu 1 recipe.

METHODS

Seventy 10-day-old male SD rat pups were randomly divided into a normal control group (n = 10), an FD model group (n = 10), and an FD with spleen deficiency model group (n = 50). The normal control group was gavaged with 0.2 mL of 2% sucrose, and the FD model group and FD with spleen deficiency model group were gavaged with 0.2 mL of 0.1% iodacetamide in 2.0% sucrose, for 6 d. From the postnatal age of 43 d, the FD with spleen deficiency model group was given modified multiple platform method (MMPM), 14 h every day, for 14 d. The FD with spleen deficiency model group was then randomly divided into an FD with spleen deficiency model group (n = 10), a western medicine group (n = 10), a low-dose Chinese herbs group (n = 10), a medium-dose Chinese herbs group (n = 10), and a high-dose Chinese herbs group (n = 10), which were gavaged with 1 mL/100 g•d of distilled water, 0.3125 mg/100 g•d of domperidone, 0.1275 g/100 g•d of Pixu 1 recipe, 0.255 g/100 g•d of Pixu 1 recipe, and 0.51 g/100 g•d of Pixu 1 recipe, for 14 d, respectively. IDH protein and mRNA expression in liver tissues was detected by Western blot, immunohistochemistry and RT-PCR.

RESULTS

Compared with the FD with spleen deficiency model group, IDH protein expression detected by immunohistochemistry was significantly higher in the normal group, FD model group, domperidone group, low-, medium-, and high-dose Pixu 1 recipe groups (P < 0.05 or P < 0.01); IDH protein expression detected by Western blot was significantly higher in the normal group, domperidone group, high-dose Pixu 1 recipe group and FD model group (P < 0.05 or P < 0.01); IDH mRNA expression detected by RT-PCR was significantly higher in the normal group, FD model group, domperidone group, high-dose Pixu 1 recipe group (P < 0.01).

CONCLUSION

FD rats with spleen deficiency have reduced energy metabolism, and Pixu 1 recipe improves spleen deficiency probably by increasing the expression of IDH protein and mRNA in FD rats with spleen deficiency.

Peptide YY3-36 and glucagon-like peptide-1 in functional dyspepsia. Secretion and role in symptom generation

OBJECTIVE

The role of peptide YY3-36 (PYY3-36), glucagon-like peptide-1 (GLP-1), and glucose homoeostasis in symptom development in functional dyspepsia (FD) is unclear. The aim was to investigate postprandial changes in plasma PYY3-36, GLP-1, glucose and insulin, and the relationship between PYY3-36, GLP-1, dyspeptic symptoms, and satiety measurements.

MATERIALS AND METHODS

Thirty-six patients with functional dyspepsia and 18 healthy controls consumed a liquid meal at two occasions. Firstly, a fixed amount of 250 mL (300 kcal) was consumed and gastric emptying was assessed using the paracetamol method. Secondly, participants drank 75 mL (90 kcal) per five min until maximal satiety. PYY3-36, GLP-1, glucose, and insulin concentrations were assessed. Satiety measures and dyspeptic symptoms were registered using visual analogue scales.

RESULTS

Gastric emptying, glucose, PYY3-36, and GLP-1 concentrations were similar in patients and controls. Patients with epigastric pain syndrome had higher postprandial insulin levels. Patients reported more satiety, nausea, and pain. Area under the curve (AUC) for GLP-1 correlated positively to nausea in patients and negatively to nausea in controls during a single meal. AUC for PYY3-36 correlated similarly to sensation of fullness in the two groups; however, the correlation was negative for the single meal and positive for the satiety test.

CONCLUSIONS

In epigastric pain syndrome, postprandial insulin secretion seems to be increased. Neither GLP-1 nor PYY3-36 secretion is altered in functional dyspepsia, but postprandial GLP-1 secretion seems to correlate with nausea and PYY3-36 to the sensation of fullness, and therefore, these hormones might be involved in symptom generation.

Effect of Aurantii Fructus Immaturus Flavonoid on the Contraction of Isolated Gastric Smooth Muscle Strips in Rats

This study was designed to investigate the effect of Aurantii fructus immaturus flavonoid (AFIF) on the contraction of isolated gastric smooth muscle in rats and explore its underlying mechanisms. Isolated antral longitudinal smooth muscle strip (ALSMS) and pyloric circular smooth muscle strip (PCSMS) of rats were suspended in tissue chambers. The responses of ALSMS and PCSMS to administration of AFIF were observed. Cyclic guanosine monophosphate (cGMP) and protein kinase G (PKG) levels of PCSMS were measured by ELISA kits. In this study, AFIF showed no significant effect on ALSMS contraction, but it dose-dependently reduced the mean contraction amplitude of PCSMS. When the concentration of AFIF reached 3000 μg/mL, 6000 μg/mL, and 10000 μg/mL, its inhibitory effect on PCSMS contraction was significant. This effect of AFIF was weakened in Ca²⁺-rich environment. And Nω-nitro-L-arginine methyl (L-NAME), the inhibitor of nitric oxide synthase (NOS), significantly inhibited AFIF's action in comparison with control (P < 0.05). After incubation with AFIF for 30 min, levels of cGMP and PKG in PCSMS were significantly increased compared with control (P < 0.05). Our results suggest that AFIF has a dose-dependent diastolic effect on PCSMS in rats, which may be related to the regulatory pathway of NO/cGMP/PKG/Ca²⁺.

Upper Gastrointestinal Symptoms Are More Frequent in Female than Male Young Healthy Japanese Volunteers as Evaluated by Questionnaire

Background/Aims

Upper gastrointestinal symptoms are more frequent and severe in female than in male outpatients in Japan. This study compared the upper gastrointestinal symptoms between healthy male and female young adult volunteers using a questionnaire.

Methods

In total, 581 third-grade medical students at Saga Medical School aged 22 to 30 years underwent upper gastrointestinal endoscopy and completed a questionnaire (frequency scale for symptoms of gastroesophageal reflux disease) from 2007 to 2013. Of these 581 students, 298 who were negative for Helicobacter pylori infection and had no particular lesions on endoscopic examination were enrolled in the present evaluation. A symptom was defined as positive when the subject evaluated the frequency of the symptom as sometimes, often, or always.

Results

The subjects comprised of 163 males (average age, 23.7 years) and 135 females (average age, 23.1 years). Upper gastrointestinal symptoms were more frequent in the females (75 of 135, 55.6%) than males (69 of 163, 42.3%; P < 0.05), with a high score for 4 symptoms (bloated stomach, heavy feeling in the stomach after meals, subconscious rubbing of the chest with the hand, and feeling of fullness while eating meals). Of the 144 subjects (69 males and 75 females) who complained of these symptoms, the females complained of dysmotility symptoms more often than did the males, but this was not true for reflux symptoms.

Conclusions

This study suggests that females develop upper gastrointestinal symptoms more frequently than do males among the young healthy Japanese population.

Small Intestinal Bacterial Overgrowth in Patients with Refractory Functional Gastrointestinal Disorders

Background/Aims

Small intestinal bacterial overgrowth (SIBO) is considered to be involved in the pathogenesis of functional gastrointestinal disorders (FGID). However, the prevalence and clinical conditions of SIBO in patients with FGID remain to be fully elucidated. Here, we examined the frequency of SIBO in patients with refractory FGID.

Methods

We prospectively enrolled patients with refractory FGID based on Rome III criteria. A glucose hydrogen breath test (GHBT) was performed using a gas analyzer after an overnight fast, with breath hydrogen concentration measured at baseline and every 15 minutes after administration of glucose for a total of 3 hours. A peak hydrogen value ≥ 10 ppm above the basal value between 60 and 120 minutes after administration of glucose was diagnosed as SIBO.

Results

A total of 38 FGID patients, including 11 with functional dyspepsia (FD), 10 with irritable bowel syndrome (IBS), and 17 with overlapping with FD and IBS, were enrolled. Of those, 2 (5.3%) were diagnosed with SIBO (one patient diagnosed with FD; the other with overlapping FD and IBS). Their symptoms were clearly improved and breath hydrogen levels decreased to normal following levofloxacin administration for 7 days.

Conclusions

Two patients initially diagnosed with FD and IBS were also diagnosed with SIBO as assessed by GHBT. Although the frequency of SIBO is low among patients with FGID, it may be important to be aware of SIBO as differential diagnosis when examining patients with refractory gastrointestinal symptoms, especially bloating, as a part of routine clinical care.

Prevalence of gastroesophageal reflux disease in children, adults, and elderly in the same community

BACKGROUND AND AIM

The prevalence of gastroesophageal reflux disease (GERD) in adults is increasing in Japan as well as worldwide likely due to increasing obesity and the decreasing rate of Helicobacter pylori infection. However, data regarding the prevalence of GERD in children and adolescents in Japan are lacking. We investigated the prevalence of GERD in children, adults, and elderly living in the same community.

METHODS

We surveyed employees of Shimane University Hospital and a related facility and their families using the Gastroesophageal Reflux Disease Questionnaire (GerdQ) and Izumo Scale instruments with demographic information (age, sex, body height, and body weight) and information regarding concurrent medication being taken for GERD. The presence of GERD was defined as a GerdQ score of ≥ 8.

RESULTS

A total of 1859 subjects (771 males, 1088 females; 6-96 years old) were eligible for assessment. The prevalence of GERD in those under 20 years old was 4.4%, which was approximately one third of the rate in adults (11.6%). GERD prevalence was closely associated with obesity in adults, but not in subjects under 20 years old. GERD and other gastrointestinal symptoms frequently overlapped in both adults and younger subjects.

CONCLUSION

We found that the prevalence of GERD in subjects under 20 years of age was lower than that in adults and not associated with obesity. Nevertheless, it is important to be aware of symptoms such as heartburn and/or regurgitation when children and adolescents seek routine clinical care.

Childhood abuse history is associated with the development of dyspepsia: a population-based survey in Japan

BACKGROUND

Functional dyspepsia (FD) is a heterogeneous disorder, and it is not clear whether childhood abuse influences the severity of dyspeptic symptoms and the type of dyspepsia. Accordingly, we administered a questionnaire survey to evaluate the association of abuse history in the development of dyspepsia.

METHODS

Study subjects were selected from among a panel of volunteers, to make equal distribution of age, sex, and residential area. A Web-based questionnaire was administered to uninvestigated dyspepsia subjects who had obtained a consultation at a medical institute, dyspepsia subjects who had not, and healthy control subjects. Dyspepsia was categorized into epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS) using the Rome III adult FGID questionnaire. Physical, sexual, and psychological abuse history and severity of dyspeptic symptoms were assessed by a questionnaire.

RESULTS

Each type of abuse was significantly prevalent in uninvestigated dyspepsia subjects. Childhood abuse history was significantly prevalent in dyspepsia. However, these abuse histories were not associated with consultation behavior. Childhood abuse was more prevalent in subjects with dyspepsia and in females. Severity of dyspeptic symptoms was significantly greater in dyspepsia subjects with a history of abuse. Childhood abuse was more prevalent in dyspepsia subjects with the overlap of EPS and PDS and in those who also had irritable bowel syndrome (IBS).

CONCLUSIONS

Childhood abuse history was associated with the development of dyspepsia especially in the overlapping diagnoses of EPS and PDS, and overlapping with IBS but not with consultation behavior. Abuse history should be assessed in the care of patients with dyspepsia.

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.

Sasang constitution affects the prevalence of functional dyspepsia

Background

Functional dyspepsia (FD), which is a very common disorder worldwide, is known to be caused by multiple factors including environmental and genetic factors. Sasang constitutional medicine (SCM) is a component of traditional Korean medicine that emphasizes inherited characteristics of the physical and psychological patterns of a patient. This study investigated whether the prevalence of FD differs depending on Sasang classification.

Methods

A total 517 subjects (190 males and 327 females) were recruited, and interviewed for the presence of FD using a Rome III-based questionnaire. The Sasang constitution of all subjects were diagnosed using a Sasang constitutional analytical tool (SCAT). A Chi-square test was performed to compare prevalence of DF among different Sasang constitutional types.

Results

Of the 517 subjects, 115 (22.2 %) met the diagnostic criteria for FD, and the prevalence was significantly higher in females (26.9 %) than males (14.2 %, p < 0.01). The Sasang-constitution-based prevalence among all subjects was 27.5 % for Taeumin, 23.1 % for Soumin, and 16.4 % for Soyangin (p = 0.055). When compared by sex, the prevalence of FD among Sasang types showed significantly different patterns between males and females (p < 0.05); in females with FD, Taeumin predominated (32.5 % compared with 29.5 % and 18.8 % for Soumin and Soyangin, respectively; p < 0.05), whereas males with FD displayed a higher prevalence of Soumin (17.3 % compared with 9.1 % and 11.3 % for Taeumin and Soyangin, respectively; p > 0.05).

Conclusions

This study identified significant differences in FD prevalence depending on Sasang constitution and sex. Our findings provide data to guide future research on the prevention and management of FD.

Novel sequential stress model for functional dyspepsia: Efficacy of the herbal preparation STW5

BACKGROUND

Many screening procedures for agents with potential usefulness in functional dyspepsia (FD) rely on animals exposed to stress early in life (neonatal maternal separation, NMS) or in adulthood (restraint stress, RS).

PURPOSE

Since many clinical cases of FD have been associated with stress in early life followed by stress in adulthood, a sequential model simulating the clinical situation is described. To explore the validity of the model, the efficacy of STW5, a multicomponent herbal preparation of proven usefulness in FD, was tested.

STUDY DESIGN/METHODS

A sequential stress model established where rats are exposed to NMS after birth followed later by RS in adulthood. Stress hormones and ghrelin were measured in plasma, while responsiveness of stomach fundus strips to smooth muscle stimulants and relaxants was assessed ex-vivo. The effectiveness of treatment with STW5 a few days before and during exposure to RS in preventing changes induced by the stress model is reported and compared to its efficacy when used in animals subjected to RS alone.

RESULTS

Responses to both stimulants and relaxants were reduced to various extents in the studied models, but treatment with STW5 tended to normalize gastric responsiveness. Plasma levels of ghrelin, corticosterone releasing factor, and corticosterone were raised by RS as well as the sequential model. Treatment with STW5 tended to prevent the deranged parameters.

CONCLUSION

The sequential stress model has a place in drug screening for potential usefulness in FD as it simulates more the clinical setting. Furthermore, the findings shed more light on the mechanisms of action of STW5 in FD.

Efficacy of mosapride and pantoprazole in treatment of children with functional dyspepsia

AIM: To compare the efficacy and safety of mosapride and pantoprazole in the treatment of children with functional dyspepsia.

METHODS: Sixty children with functional dyspepsia were selected and randomly divided into either an observation group or a control group, with 30 cases in each group. Subjects in the observation group were treated with mosapride (5 mg, po, tid). Subjects in the control group were treated with pantoprazole (40 mg, po, qd). After 2 wk of treatment, the symptom score and clinical efficacy of the two groups were observed and compared.

RESULTS: After treatment, the scores of total symptoms, abdominal fullness after meals, early satiety, epigastric pain, and epigastric burning sensation in the two groups were significantly lower than those before the treatment (observation group: 14.39 ± 7.13 vs 20.79 ± 11.36, 4.39 ± 1.37 vs 4.84 ± 5.16, 3.89 ± 1.19 vs 4.17 ± 4.43, 3.74 ± 1.05 vs 6.37 ± 5.36, 3.95 ± 1.98 vs 6.73 ± 6.21; control group: 13.57 ± 6.42 vs 20.68 ± 11.41, 3.27 ± 1.16 vs 4.91 ± 5.21, 3.16 ± 1.08 vs 4.20 ± 4.52, 4.29 ± 1.23 vs 6.29 ± 5.83, 4.17 ± 1.54 vs 6.82 ± 6.08; P < 0.05 for all). The scores of total symptoms, abdominal fullness after meals, early satiety, epigastric pain, and epigastric burning sensation after treatment showed no significant differences between the two groups (P > 0.05 for all). The difference in the total response rate between the two groups was not statistically significant (70.00% vs 66.67%, P > 0.05). There were no significant differences in the response rates for postprandial distress syndrome and epigastric pain syndrome between the two groups (70.59% vs 64.71%, 69.23% vs 69.23%, P > 0.05 for both).

CONCLUSION: Both mosapride and pantoprazole have good efficacy in the treatment of children with functional dyspepsia.

Effects of GC7101, a Novel Prokinetic Agent on Gastric Motor Function: Ex Vivo Study

Background/Aims

GC7101, an extract of Lonicera Flos, is a novel developing drug for reflux esophagitis and functional dyspepsia. However, the drug’s exact pharmacological mechanism of action remains unclear. This study assessed the effects of GC7101 on gastrointestinal (GI) motor function.

Methods

We used male guinea pigs to evaluate the effects of GC7101 on GI motility. The contraction of antral circular muscle in the presence of different doses of GC7101 was measured in a tissue bath. The prokinetic effects of GC7101 were tested using the charcoal transit assay from the pylorus to the most distal point of migration of charcoal mixture. To clarify the mechanism of action of GC7101, atropine, dopamine and the selective 5-hydroxytryptamine 4 receptor antagonist, GR113808 were used.

Results

The maximal amplitude of circular muscle contraction was induced by 5 mg mL⁻¹ GC7101. The area under the curve of contraction was significantly increased at 5 mg mL⁻¹ GC7101. Addition of 10⁻⁶ M atropine, 10⁻⁸ M dopamine or 10⁻⁷ M GR 113808 to GC7101 5 mg mL⁻¹ decreased the amplitude and area under curve compared to GC7101 5 mg mL⁻¹ alone. GC7101 accelerated GI transit in a dose dependent manner except 100 mg kg⁻¹. Delayed GI transit caused by atropine, dopamine and GR 113808 was restored by GC7101 50 mg kg⁻¹.

Conclusions

GC7101, an extract of Lonicera Flos, exerts a gastric prokinetic effect in guinea pig through cholinergic, antidopaminergic and serotonergic mechanisms. Therefore, GC7101 might be a novel drug for the treatment of functional dyspepsia.

Overlap in patients with dyspepsia/functional dyspepsia

Patients with dyspepsia/functional dyspepsia (FD) show frequent overlapping of other gastrointestinal (GI) diseases, such as irri-table bowel syndrome, and non-GI diseases, in addition to internal subgroup overlapping. These overlap patients have more frequent or more severe symptoms, poorer health-related quality of life and higher somatization scores, and they are more like-ly to experience anxiety, depression or insomnia compared to non-overlap patients. The higher prevalence of overlap in patients with dyspepsia/FD is not by chance, indicating common pathogeneses, including visceral hypersensitivity, altered GI motility, in-fection, and stressful early life events. There are few clinical trials targeting overlap in patients with dyspepsia/FD, and no ther-apeutic strategy has been established. Further studies in this research area are needed. In this review, we describe the epidemi-ology, pathogenesis and treatment of overlap in patients with dyspepsia/FD.(J Neurogastroenterol Motil 2014;20:447-457).

Association of genetic variants in GNβ3 with functional dyspepsia: a meta-analysis

BACKGROUND

Functional dyspepsia (FD) is a functional upper gastrointestinal disorder. The etiology and pathogenesis of FD remain unclear, with genetic factors playing an important role. Previous studies investigated the association of C825T in GNβ3 with FD, with conflicting results reported.

AIMS

The aim of this meta-analysis is to assess the association of genetic variants in GNβ3 with FD.

METHODS

We performed a systematic literature search in PubMed, Cochrane Library, Google Scholar, and Web of Knowledge, and conducted a meta-analysis to assess the association of C825T in GNβ3 with FD. For sensitivity analysis, we analyzed the association between C825T and subtypes of FD. We also performed meta-analyses separately for individual ethnic groups/countries of origin.

RESULTS

A total of eight studies met the eligibility criteria and were included in our analyses. Our meta-analysis finds no association between 825CC and FD (OR 1.19, 95% CI 0.84-1.67, p = 0.328). However, the association is significant under an additive model (OR 0.59, 95% CI 0.38-0.92, p = 0.018). Sensitivity analysis indicated a significant association of C825T with FD in participants from Korea but not in those from Japan, Europe, or the United States. We also detected a significant association of this SNP with dysmotility.

CONCLUSIONS

The genetic variant C825T in GNβ3 is significantly associated with FD under an additive model and the association is race-specific. Further studies with larger samples sizes are needed to validate our findings and to explore the potential mechanism underlying the association.

Brain-gut axis in the pathogenesis of Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is the main pathogenic factor for upper digestive tract organic diseases. In addition to direct cytotoxic and proinflammatory effects, H. pylori infection may also induce abnormalities indirectly by affecting the brain-gut axis, similar to other microorganisms present in the alimentary tract. The brain-gut axis integrates the central, peripheral, enteric and autonomic nervous systems, as well as the endocrine and immunological systems, with gastrointestinal functions and environmental stimuli, including gastric and intestinal microbiota. The bidirectional relationship between H. pylori infection and the brain-gut axis influences both the contagion process and the host’s neuroendocrine-immunological reaction to it, resulting in alterations in cognitive functions, food intake and appetite, immunological response, and modification of symptom sensitivity thresholds. Furthermore, disturbances in the upper and lower digestive tract permeability, motility and secretion can occur, mainly as a form of irritable bowel syndrome. Many of these abnormalities disappear following H. pylori eradication. H. pylori may have direct neurotoxic effects that lead to alteration of the brain-gut axis through the activation of neurogenic inflammatory processes, or by microelement deficiency secondary to functional and morphological changes in the digestive tract. In digestive tissue, H. pylori can alter signaling in the brain-gut axis by mast cells, the main brain-gut axis effector, as H. pylori infection is associated with decreased mast cell infiltration in the digestive tract. Nevertheless, unequivocal data concerning the direct and immediate effect of H. pylori infection on the brain-gut axis are still lacking. Therefore, further studies evaluating the clinical importance of these host-bacteria interactions will improve our understanding of H. pylori infection pathophysiology and suggest new therapeutic approaches.

Functional dyspepsia symptom resolution after Helicobacter pylori eradication with two different regimens

INTRODUCTION

Functional dyspepsia (FD), a common functional gastrointestinal disorder, has a complex underlying pathophysiological mechanism that involves changes in gastric motility, visceral hypersensitivity, genetic susceptibility, psychosocial factors and Helicobacter pylori infection. Although there are several H. pylori eradication treatments, there is not enough data that compare these different eradication treatments for FD symptom resolution. Most previous studies have focused on the eradication rates of H. pylori rather than symptom relief in FD.

AIM

In this regard, we aimed to clarify if there is any difference between standard triple therapy and sequential therapy for symptom resolution of FD patients with H. pylori, using a validated health quality index.

MATERIAL AND METHODS

A total of 194 patients were included in this study. The patients were randomly assigned to receive standard triple therapy (omeprazole, amoxicilline and clarithromycin for 14 days) or sequential therapy (omeprazole plus amoxicilline for 7 days and omeprazole twice daily, metronidazole and clarithromycin for a subsequent 7 days) by a blind physician for H. pylori status. Outcome measures were based on symptomatic improvement at 12 months using a validated measure of subjective well-being (Gastrointestinal Symptom Rating Scale - GSRS).

RESULTS

We observed significant symptom resolution at 12 months in both treatment groups. On the other hand, there was no difference between the sequential or standard triple therapy groups regarding the alleviation of symptoms.

CONCLUSIONS

No difference for symptom relief exists between sequential and triple therapy in patients with FD.

Gastric sensitivity and reflexes: basic mechanisms underlying clinical problems

Both reflex and sensory mechanisms control the function of the stomach, and disturbances in these mechanisms may explain the pathophysiology of disorders of gastric function. The objective of this report is to perform a literature-based critical analysis of new, relevant or conflicting information on gastric sensitivity and reflexes, with particular emphasis on the comprehensive integration of basic and clinical research data. The stomach exerts both phasic and tonic muscular (contractile and relaxatory) activity. Gastric tone determines the capacity of the stomach and mediates both gastric accommodation to a meal as well as gastric emptying, by partial relaxation or progressive recontraction, respectively. Perception and reflex afferent pathways from the stomach are activated independently by specific stimuli, suggesting that the terminal nerve endings operate as specialized receptors. Particularly, perception appears to be related to stimulation of tension receptors, while the existence of volume receptors in the stomach is uncertain. Reliable techniques have been developed to measure gastric perception and reflexes both in experimental and clinical conditions, and have facilitated the identification of abnormal responses in patients with gastric disorders. Gastroparesis is characterised by impaired gastric tone and contractility, whereas patients with functional dyspepsia have impaired accommodation, associated with antral distention and increased gastric sensitivity. An integrated view of fragmented knowledge allows the design of pathophysiological models in an attempt to explain disorders of gastric function, and may facilitate the development of mechanistically orientated treatments.

Prevalence and risk factors of functional dyspepsia: a nationwide multicenter prospective study in Korea

GOALS

To evaluate the prevalence of functional dyspepsia (FD) and its risk factors.

BACKGROUND

FD is a common disorder, but its negative influences greatly affect the quality of life. The predictive factors of FD are still ambiguous.

STUDY

A total of 3399 participants underwent screening gastroscopy at one of 7 nationwide health care centers in Korea and who completed a questionnaire. Atrophic gastritis was defined by gastroscopy. Serologic Helicobacter pylori immunoglobulin G antibody was measured by enzyme-linked immunosorbent assay.

RESULTS

Of the 3399 participants who did not have organic diseases, 694 (20.4%) had dyspeptic symptoms such as epigastric pain/soreness or postprandial discomfort. Among the 694 participants, atrophic gastritis and positive H. pylori serology were found in 282 (40.6%) and 422 (60.8%), respectively; these proportions were not different from the remaining asymptomatic subjects. Multivariate analysis showed that having relatives with gastric cancer [odds ratio (OR), 1.35; 95% confidence interval (CI), 1.01-1.81], education below college (OR, 1.32; 95% CI, 1.06-1.64), and high-salt diet (OR, 1.33; 95% CI, 1.05-1.68) were associated with FD symptoms.

CONCLUSIONS

FD symptoms were frequently found in the health check-up subjects. Relatives of gastric cancer, education below college, and high-salt diet were risk factors of FD, suggesting that FD is a multifactorial disease.

Role of metabotropic glutamate receptors in the regulation of pancreatic functions

The pancreas consists of two major divisions, the exocrine and the endocrine pancreas. Recent data from our laboratory have shown that the functions of the two divisions are under modulatory regulation by separate neurocircuits that originate in the dorsal motor nucleus of the vagus (DMV). Metabotropic glutamate receptors (mGluRs) are expressed throughout the central nervous system and have been implicated in the modulation of synaptic transmission. mGluRs consist of three groups of receptors, which can be distinguished based on their pharmacological properties and second messenger systems. Group I mGluRs predominantly increase, whereas group II and III mGluRs decrease synaptic transmission. Group II and group III mGluRs are present on excitatory and inhibitory synaptic terminals impinging on pancreas-projecting DMV neurons. We have shown that group II mGluRs regulate both exocrine pancreatic secretions and insulin release, whereas group III mGluRs only regulate insulin release. Several mGluR agonists and antagonists have been shown to have clinical uses for disorders accompanied by abnormal synaptic transmission, including anxiety and Parkinson's disease. Moreover, a negative allosteric modulator of Group I mGluRs is effective in alleviating symptoms of gastro-esophageal reflux disease (GERD). Since the role of the three mGluR groups in mediating different gastrointestinal (GI) functions appears to be highly specific, the use of agonists or antagonists directed at a single receptor group could potentially provide highly selective targets for the treatment of GI disorders including GERD, functional dyspepsia and acute pancreatitis.

The role of ghrelin in patients with functional dyspepsia and its potential clinical relevance (Review)

Functional dyspepsia (FD) is a functional gastrointestinal disorder (FGID). According to the Rome III consensus, FD is divided into 2 subgroups: epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS). Although multiple mechanisms of FD pathogenesis have been suggested, its underlying etiology and pharmacological therapy remain unclear. Ghrelin is a gut-derived peptide found in the stomach. It plays a role in the regulation of gastric motility and appetite. The ghrelin gene encodes 3 molecular forms, acyl ghrelin, des-acyl ghrelin and obestatin. Acyl ghrelin acts as an endogenous ligand for growth hormone secretagogue receptor; furthermore, it is orexigenic, with effects on food intake, energy homeostasis and gastrointestinal motility. Des-acyl ghrelin exerts an opposite effect to acyl ghrelin. Obestatin exerts an inhibitory effect on the motor activity of the antrum and duodenum in fed animals. These peptides exert differential effects on gut motility and food intake. The therapeutic potential of ghrelin has attracted attention due to its varied bioactivities. Certain studies have shown that total ghrelin levels are significantly lower in patients with FD compared with healthy volunteers and that the acyl ghrelin levels of patients with FD are higher compared with healthy volunteers. However, a recent study demonstrated that acyl ghrelin levels in patients with PDS were lower compared with healthy volunteers; the association between FD and other ghrelin family gene products also remains unclear. Although certain studies have demonstrated the beneficial effects of acyl ghrelin administration and its agonist in patients with FD, only a few clinical reports exist. Further studies are required in order to examine the effects of ghrelin on FD.

Advances in understanding the relationship between functional dyspepsia and mental factors

The co-morbidity of functional dyspepsia (FD) and mental disorders is 42%-61%. Growing evidence shows that visceral hypersensitivity and abnormality of brain gut peptides are possibly responsible for the interactions between FD and mental disorders, and the brain-intestine axis plays a crucial role in the development of visceral pain. Functional magnetic resonance imaging is a novel and effective tool for studying visceral hypersensitivity. Gastric pain activates a wide range of cortical and subcortical structures, including the cortex of frontal lobe, anterior cingulate cortices, insula, thalamus and amygdala. Several studies show that selected serotonergic antidepressants and some traditional Chinese medicine can improve the symptoms, especially pain, of FD; however, the underlying mechanisms remain unclear.