Functional dyspepsia is associated with GNβ3 C825T and CCK-AR T/C polymorphism

Meta-Analysis of the Association Between 5-Hydroxytryptamine Transporter Gene-Linked Polymorphic Region and Functional Dyspepsia and its Subtypes

Background: Association studies of variations in the 5-hydroxytryptamine (5-HT, serotonin) transporter gene-linked polymorphic region (5-HTTLPR) and functional dyspepsia (FD) have yielded contradictory results. Hence, we performed a meta-analysis to clarify inconsistencies between the 5-HTTLPR polymorphism with FD and it subtypes. Methods: We performed a literature search in PubMed, Embase, Web of Science, Cochrane Library, and CNKI, including articles published until March 2022. We calculated and pooled odds ratios (ORs) with their 95% confidence intervals (CIs) in Stata 15.0. Data extraction was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Cochrane Handbook for Systematic Reviews of Interventions. Results: The meta-analysis included six studies, comprising 488 cases and 1513 healthy controls. We did not observe a significant association between the 5-HTTLPR polymorphism and FD in the overall population. In subgroup analyses, the 5-HTTLPR polymorphism was significantly associated with FD-subtype epigastric pain syndrome (EPS) (SS vs. LL+LS, OR = 0.620, 95% CI: 0.414-0.930; SS vs. LS, OR = 0.640, 95% CI: 0.417-0.980; S vs. L, OR = 0.655, 95% CI: 0.471-0.911). However, no association was observed with the other subtype, postprandial distress syndrome (PDS). Conclusion: While the 5-HTTLPR polymorphism had no relationship with FD overall, splitting the disease into its subtypes revealed a clear association with EPS.

Current Treatment Options and Therapeutic Insights for Gastrointestinal Dysmotility and Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) have been re-named as disorders of gut-brain interactions. These conditions are not only common in clinical practice, but also in the community. In reference to the Rome IV criteria, the most common FGIDs, include functional dyspepsia (FD) and irritable bowel syndrome (IBS). Additionally, there is substantial overlap of these disorders and other specific gastrointestinal motility disorders, such as gastroparesis. These disorders are heterogeneous and are intertwined with several proposed pathophysiological mechanisms, such as altered gut motility, intestinal barrier dysfunction, gut immune dysfunction, visceral hypersensitivity, altered GI secretion, presence and degree of bile acid malabsorption, microbial dysbiosis, and alterations to the gut-brain axis. The treatment options currently available include lifestyle modifications, dietary and gut microbiota manipulation interventions including fecal microbiota transplantation, prokinetics, antispasmodics, laxatives, and centrally and peripherally acting neuromodulators. However, treatment that targets the pathophysiological mechanisms underlying the symptoms are scanty. Pharmacological agents that are developed based on the cellular and molecular mechanisms underlying pathologies of these disorders might provide the best avenue for future pharmaceutical development. The currently available therapies lack long-term effectiveness and safety for their use to treat motility disorders and FGIDs. Furthermore, the fundamental challenges in treating these disorders should be defined; for instance, 1. Cause and effect cannot be disentangled between symptoms and pathophysiological mechanisms due to current therapies that entail the off-label use of medications to treat symptoms. 2. Despite the knowledge that the microbiota in our gut plays an essential part in maintaining gut health, their exact functions in gut homeostasis are still unclear. What constitutes a healthy microbiome and further, the precise definition of gut microbial dysbiosis is lacking. More comprehensive, large-scale, and longitudinal studies utilizing multi-omics data are needed to dissect the exact contribution of gut microbial alterations in disease pathogenesis. Accordingly, we review the current treatment options, clinical insight on pathophysiology, therapeutic modalities, current challenges, and therapeutic clues for the clinical care and management of functional dyspepsia, gastroparesis, irritable bowel syndrome, functional constipation, and functional diarrhea.

Role of microRNAs in Disorders of Gut-Brain Interactions: Clinical Insights and Therapeutic Alternatives

Disorders of gut–brain interactions (DGBIs) are heterogeneous in nature and intertwine with diverse pathophysiological mechanisms. Regular functioning of the gut requires complex coordinated interplay between a variety of gastrointestinal (GI) cell types and their functions are regulated by multiple mechanisms at the transcriptional, post-transcriptional, translational, and post-translational levels. MicroRNAs (miRNAs) are small non-coding RNA molecules that post-transcriptionally regulate gene expression by binding to specific mRNA targets to repress their translation and/or promote the target mRNA degradation. Dysregulation of miRNAs might impair gut physiological functions leading to DGBIs and gut motility disorders. Studies have shown miRNAs regulate gut functions such as visceral sensation, gut immune response, GI barrier function, enteric neuronal development, and GI motility. These biological processes are highly relevant to the gut where neuroimmune interactions are key contributors in controlling gut homeostasis and functional defects lead to DGBIs. Although extensive research has explored the pathophysiology of DGBIs, further research is warranted to bolster the molecular mechanisms behind these disorders. The therapeutic targeting of miRNAs represents an attractive approach for the treatment of DGBIs because they offer new insights into disease mechanisms and have great potential to be used in the clinic as diagnostic markers and therapeutic targets. Here, we review recent advances regarding the regulation of miRNAs in GI pacemaking cells, immune cells, and enteric neurons modulating pathophysiological mechanisms of DGBIs. This review aims to assess the impacts of miRNAs on the pathophysiological mechanisms of DGBIs, including GI dysmotility, impaired intestinal barrier function, gut immune dysfunction, and visceral hypersensitivity. We also summarize the therapeutic alternatives for gut microbial dysbiosis in DGBIs, highlighting the clinical insights and areas for further exploration. We further discuss the challenges in miRNA therapeutics and promising emerging approaches.

Digestive promoting effect and mechanism of Jiao Sanxian in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao Sanxian, a customary term for the three Traditional Chinese Medicines of charred hawthorn (Crataegi Fructus), charred malt (Hordei Fructus Germinatus) and Liu Shenqu (Massa Medicata Fermentata), is a classic prescription for the treatment of functional dyspepsia (FD). This prescription is called "Jiao Sanxian" in China because people believe that it is a miracle medicine for enhancing digestion and improving stagnation of digestive system. Even though Jiao Sanxian is widely used in clinical treatment, the underlying mechanism has not been clarified to date.

AIM OF THE STUDY

The present study is aimed to explore the efficacy and mechanism of Jiao Sanxian in improving the symptoms of FD in rats by using multiple pharmacological methods.

MATERIALS AND METHODS

The Sprague Dawley (SD) rats were divided into control, model, Jiao Sanxian decoction low-dosage (JSXD LD), Jiao Sanxian decoction medium-dosage (JSXD MD), and Jiao Sanxian decoction high-dosage (JSXD HD) group at random. A FD model was established with reserpine, and animals were given intragastric administration. During this period, weight and food intake of animals were recorded. Samples of rat gastric antrum, spleen, and duodenum were collected for pathological staining and immunohistochemical determination of Ghrelin protein expression after 19 days of treatment. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration of related brain gut peptides in serum. Moreover, 16S rRNA sequencing was used to valuate the influence of intestinal flora structure of the cecal contents of experimental rats. And plasma metabolomics by Ultra Performance Liquid Chromatography coupled with Quadrupole-Time-of-Flight mass spectrometry (UPLC-Q/TOF-MS) were performed to further reveal the mechanism of action.

RESULTS

Jiao Sanxian decoction (JSXD) group with different dosage could increase body weight and food intake, improve histopathological changes, and alter disordered brain gut peptides in FD rats. 16S rRNA sequencing results described that JSXD improved the disorder of structural composition, biodiversity and function of gut microbiota in FD rats. Metabolomics illustrated 26 metabolites with JSXD treatment underwent continuous changes, which revealed JSXD might exert digestive effect by ameliorating abnormal metabolic pathways. The most relevant metabolic pathways were arachidonic acid metabolism, pyruvate metabolism, glycerophospholipid metabolism, alanine, aspartate and glutamate metabolism.

CONCLUSIONS

JSXD can improve functional dyspepsia in rats and the mechanism is related to regulate secretion of brain gut peptides, significantly improve the disorder of intestinal flora and ameliorated multi-metabolic pathways.

Characterizing clinical features and location-specific gene expression profiles associated with pain burden in children with functional dyspepsia

BACKGROUND

In children with functional dyspepsia (FD), genes involved in pain modulation may be differentially expressed contributing to chronic pain.

METHODS

Children with suspected FD (cases) and known eosinophilic esophagitis (controls) undergoing esophagogastroduodenoscopy completed the Rome IV Diagnostic, Pain Burden and Frequency Severity-Duration questionnaires. Two antral and two duodenal biopsies were collected and relative fold differences in gene expression for 84 pain-associated genes compared to pain-free controls were calculated.

RESULTS

Sixty-six subjects with FD (postprandial distress syndrome = 34, epigastric pain syndrome = 7, both = 25; 65% female; mean age 13.7 years) and 13 pain-free controls (8% female; mean age 12.7) were studied. There were no significant differences in antral and duodenal eosinophilic counts or distribution between the pain and pain-free groups. Pain severity and burden did not differ significantly between FD subgroups and neither measure significantly correlated with eosinophil counts in the antrum or duodenum. Analysis of 47 antral and 39 duodenal biospecimens revealed 5 candidate genes significantly associated with pain burden: antral EDN1, PTGES3 and duodenal HTR1A, P2Y1, SCN3A (p < 0.01). Subsequent stringent statistical analysis comparing those with significant pain versus no pain revealed antral PTGES3 and duodenal SCN3A were the highest priority candidate genes (p < 0.001).

CONCLUSIONS

Pain burden in pediatric FD may be linked to antral EDN1, PTGES3 and duodenal HTR1A, P2Y1, SCN3A differential expression. These genes are known to be involved in pain conduction, modulation, and neurotransmission, suggesting potential therapeutic targets for managing pain in FD.

Developing the Patient Health Questionnaire-8 for a greater impact on the quality of life of patients with functional dyspepsia compared to Somatic Symptom Scale-8

Background

To develop the Patient Health Questionnaire-8 (PHQ-8) as a more reliable approach than the Somatic Symptom Scale-8 (SSS-8), evaluating somatization which might be a critical factor influencing the quality of life (QoL) in patients with functional dyspepsia (FD). Also, the effects of somatization on QoL of FD patients were assessed by these two approaches.

Methods

Herein, 612 FD patients completed a questionnaire involving 25 items. 8/25 items were selected to develop the PHQ-8 by four methods of discrete degree, correlation coefficient, factor analysis, and Cronbach’s α coefficient. Reliability and validity of the PHQ-8 and the SSS-8 were compared by principal component and confirmatory factor analyses. The effects of somatization, depression, and anxiety on the Nepean Dyspepsia Index (NDI) for QoL were explored by Pearson’s correlation coefficient and linear regression analysis.

Results

The Cronbach’s α coefficient for the PHQ-8 and the SSS-8 was 0.601 and 0.553, respectively, and the cumulative contribution rate of three extracted factors for the developed PHQ-8 and SSS-8 was 55.103% and 51.666%, respectively. Somatization evaluated by the PHQ-8 (r = 0.309, P < 0.001) and the SSS-8 (r = 0.281, P < 0.001) was found to be correlated to NDI. The model used for the PHQ-8 showed that the values of goodness-of-fit index (GFI) and adjusted GFI (AGFI) were 0.984 and 0.967, respectively, which indicated that the model fitted well. Linear regression analysis unveiled that somatization (β = 0.270, P < 0.001), anxiety (β = 0.163, P < 0.001), and depression (β = 0.136, P = 0.003) assessed by the PHQ-8 were correlated to NDI. In addition, somatization (β = 0.250, P < 0.001), anxiety (β = 0.156, P < 0.001), and depression (β = 0.155, P = 0.001) evaluated by the SSS-8 were correlated to NDI.

Conclusions

PHQ-8 showed a superior reliability and validity, and somatization assessed by the developed PHQ-8 showed a greater influence on the QoL of FD patients as compared to the SSS-8. Our findings suggested that the developed PHQ-8 may show improvement in a reliable assessment of the effects of somatization on FD patients in lieu of the SSS-8.

Analysis of risk factors and prevention strategies for functional delayed gastric emptying in 1243 patients with distal gastric cancer

Background

Analysis of the risk factors associated with functional delayed gastric emptying after distal gastric cancer surgery to provide a basis for further reduction of the incidence of this complication.

Methods

Total of 1382 patients with distal gastric cancer from January 2016 to October 2018 were enrolled. Correlation analysis was performed in 53 patients with FDGE by logistic regression. Subgroup risk analysis was performed in 114 patients with preoperative pyloric obstruction. A Pearson Chi-square analysis was used to compare categorical variables between normal distribution groups. Meanwhile, a t test was used to compare continuous variables between groups. Odds ratio (OR) was used for comparison of the two groups, and it was summarized with its 95% confidence interval (CI) and p value using logistic regression.

Result

In multivariable analysis, age (OR 1.081, 95% CI, 1.047–1.117), BMI (OR 1.233, 95% CI, 1.116–1.363), preoperative pyloric obstruction (OR 3.831, 95% CI, 1.829–8.023), smaller volume of residual stomach (OR 1.838, 95% CI, 1.325–6.080), and anastomosis in greater curvature perpendicular (OR 3.385, 95% CI, 1.632–7.019) and in greater curvature parallel (OR 2.375, 95% CI, 0.963–5.861) were independent risk factors of FDGE. In the preoperative pyloric obstruction group, higher BMI (OR 1.309, 95% CI, 1.086–1.579) and preoperative obstruction time (OR 1.054, 95% CI, 1.003–1.108) were independent risk factors of FDGE and preoperative gastrointestinal decompression (OR 0.231, 95% CI, 0.068–0.785) was independent protective factor of FDGE.

Conclusion

Adequate gastrointestinal decompression should be performed before the operation to reduce the incidence of postoperative gastroparesis in patients with preoperative pyloric obstruction. We also could improve the surgical methods to reduce the occurrence of FDGE, such as controlling the size of the residual stomach, ensuring blood supply. Especially selecting an appropriate stapler and anastomosis during the anastomosis process, the occurrence of FDGE can be reduced.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-020-02085-2.

Gene Polymorphisms and Susceptibility to Functional Dyspepsia: A Systematic Review and Meta-Analysis

Functional dyspepsia (FD) is a common chronic gastrointestinal disorder with a complex, undefined mechanism. Clustering of patients with FD in families highlights the role of genetic factors in the pathogenesis of FD. We performed a systematic review and meta-analysis to clarify the associations between specific gene polymorphisms and FD susceptibility. PubMed, EMBASE, the Cochrane Library, and HuGE database were searched. An additive model was adopted to determine whether previous studied genes are associated with FD susceptibility. Carriers of minor allele in GNB3 825C>T (OR = 1.15, 95% CI 0.99-1.34, P = 0.07), SCL6A4 5HTTLPR (OR = 0.92, 95% CI 0.75-1.12, P = 0.40), and CCK-1R 779T>C (OR = 0.86, 95% CI 0.72-1.03, P = 0.09) genes failed to demonstrate susceptibility to FD. In a subgroup analysis, only minor allele (T) in GNB3 825C>T was associated with an increased susceptibility to the epigastric pain syndrome subtype (OR = 1.34, 95% CI 1.10-1.63, P = 0.003). Our meta-analysis based on available studies using an additive model failed to show that GNB3, SCL6A4, and CCK-1R polymorphisms are associated with FD susceptibility.

Immunopathological and molecular basis of functional dyspepsia and current therapeutic approaches

INTRODUCTION

Functional dyspepsia (FD) is widespread with 20% prevalence worldwide and a significant economic burden due to health care cost and constraints on daily activities of patients. Despite extensive investigation, the underlying causes of dyspepsia in a majority of patients remain unknown. Common complaints include abdominal discomfort, pain, burning, nausea, early satiety, and bloating. Motor dysfunction of the gut was long considered a major cause, but recent investigations suggest immune-based pathophysiological and molecular events in the duodenum are more probable contributing factors. Areas Covered: Inflammatory mediators and immune cells including duodenal eosinophils, intraepithelial lymphocytes, and T-cells have been implicated in the underlying cause of disease process, as have genetic factors. In this article, we critically reviewed findings, identified gaps in knowledge and suggested future directions for further investigation to identify targets and develop better therapeutic approaches. Expert commentary: Impaired gastric accommodation, slow gastric emptying, and increased visceral sensitivity have long been thought of as main causal factors of FD. However, more recent identification of eosinophilic degranulation and recruitment of T cells that induce mild duodenal inflammation are giving rise to new insights into immune-mediated pathophysiology. These insights offer promising avenues to explore for immune-mediated therapy in the future.

Does colectomy predispose to small intestinal bacterial (SIBO) and fungal overgrowth (SIFO)?

Objectives

After subtotal colectomy, 40% of patients report chronic gastrointestinal symptoms and poor quality of life. Its etiology is unknown. We determined whether small intestinal bacterial overgrowth (SIBO) or small intestinal fungal overgrowth (SIFO) cause gastrointestinal symptoms after colectomy.

Methods

Consecutive patients with unexplained abdominal pain, gas, bloating and diarrhea (>1 year), and without colectomy (controls), and with colectomy were evaluated with symptom questionnaires, glucose breath test (GBT) and/or duodenal aspiration/culture. Baseline symptoms, prevalence of SIBO/SIFO, and response to treatment were compared between groups.

Results

Fifty patients with colectomy and 50 controls were evaluated. A significantly higher (p = 0.005) proportion of patients with colectomy, 31/50 (62%) had SIBO compared to controls 16/50 (32%). Patients with colectomy had significantly higher (p = 0.017) prevalence of mixed SIBO/SIFO 12/50 (24%) compared to controls 4/50 (8%). SIFO prevalence was higher in colectomy but not significant (p = 0.08). There was higher prevalence of aerobic organisms together with decreased anaerobic and mixed organisms in the colectomy group compared to controls (p = 0.008). Patients with colectomy reported significantly greater severity of diarrhea (p = 0.029), vomiting (p < 0.001), and abdominal pain (p = 0.05) compared to controls, at baseline. After antibiotics, 74% of patients with SIBO/SIFO in the colectomy and 69% in the control group improved (p = 0.69).

Conclusion

Patients with colectomy demonstrate significantly higher prevalence of SIBO/SIFO and greater severity of gastrointestinal symptoms. Colectomy is a risk factor for SIBO/SIFO.

Functional Dyspepsia: Advances in Diagnosis and Therapy

Functional dyspepsia (FD) is a common but under-recognized syndrome comprising bothersome recurrent postprandial fullness, early satiety, or epigastric pain/burning. Epidemiologically, there are two clinically distinct FD syndromes (although these often overlap clinically): postprandial distress syndrome (PDS; comprising early satiety or meal-related fullness) and epigastric pain syndrome. Symptoms of gastroesophageal reflux disease overlap with FD more than expected by chance; a subset has pathological acid reflux. The pre-test probability of FD in a patient who presents with classical FD symptoms and no alarm features is high, approximately 0.7. Coexistent heartburn should not lead to the exclusion of FD as a diagnosis. One of the most exciting observations in FD has been the consistent finding of increased duodenal eosinophilia, notably in PDS. Small bowel homing T cells, signaling intestinal inflammation, and increased cytokines have been detected in the circulation, and elevated tumor necrosis factor-α levels have been significantly correlated with increased anxiety. Postinfectious gastroenteritis is a risk factor for FD. Therapeutic options remain limited and provide only symptomatic benefit in most cases. Only one therapy is known to change the natural history of FD–Helicobacter pylori eradication. Treatment of duodenal eosinophilia is under investigation.

Functional dyspepsia and gastroparesis

PURPOSE OF REVIEW

This review summarizes recent progress in the epidemiology, pathophysiology and treatment of functional dyspepsia and gastroparesis.

RECENT FINDINGS

The definition of functional dyspepsia and its subgroups has been revised in the recent Rome IV consensus. In gastroparesis, the symptom pattern and its similarities and differences from functional dyspepsia have been a focus of recent research. In functional dyspepsia, pathophysiological research continued to evaluate gastric sensorimotor dysfunctions, but low-grade inflammatory changes and loss of mucosal integrity in the duodenum is a new topic of intense research. Treatment advances include new prokinetics such as acotiamide and the ghrelin receptor agonist relamorelin. The efficacy of tricyclic antidepressants was recently reviewed and mirtazapine is a new agent used in the treatment of functional dyspepsia and gastroparesis. In gastroparesis, research has focused on the role of macrophages in loss of interstitial cells of Cajal, and on the role of pyloric resistance as a target for therapy, using botulinum toxin injection and gastric per-endoscopic pyloric myotomy.

SUMMARY

The functional dyspepsia definition and subgrouping were updated in the Rome IV consensus. Research focuses on duodenal mucosal alterations in functional dyspepsia and pyloric resistance in gastroparesis. New treatments include novel prokinetics and pylorus-directed interventions.

Functional dyspepsia susceptibility is related to CD14, GNB3, MIF, and TRPV1 gene polymorphisms in the Greek population

BACKGROUND

Functional dyspepsia (FD) susceptibility might be influenced by polymorphisms of genes related to inflammation (CD14, macrophage migration inhibitory factor [MIF]), motor (GNB3), and sensory dysfunction (GNB3, TRPV1). We examined the association between CD14 rs2569190, GNB3 rs5443, MIF rs222747, and TRPV1 rs755622 gene polymorphisms with FD (Rome III criteria) in the Greek population.

METHODS

We genotyped 174 dyspeptics (115 with epigastric pain syndrome; 41% Helicobacter pylori positive) and 181 controls using polymerase chain reaction-based methods and we measured disease symptoms' burden with a modified Gastrointestinal Symptoms Related Scale.

KEY RESULTS

Homozygous for the TT genotype and the T allele of the CD14 gene were significantly associated (OR [95% CI]) with FD (2.65 [1.42-4.94] and 1.67 [1.23-2.26], respectively). The CT, TT genotypes, and T allele frequencies of GNB3 showed also significant association with FD (2.18 [1.35-3.54], 3.46 [1.30-9.23], and 2.18 [1.48-3.19]). While heterozygous GC MIF genotype was more common in dyspeptics (1.67 [1.07-2.60]), homozygous CC genotype and the C allele of TRPV1 gene were more prevalent in controls (0.47 [0.25-0.87] and 0.69 [0.51-0.92], respectively). None of the gene polymorphism was related either to dyspepsia clinical syndrome type or to the H. pylori infection. Among dyspeptics, CD14 TT genotype was related to lower epigastric pain burden score (p<.011); CD14 CT genotype was related to higher epigastric burning and nausea burden scores (p<.04) while belching score was lower (p=.027) in MIF CG dyspeptics.

CONCLUSION & INFERENCES

Functional dyspepsia susceptibility is related to CD14, GNB3, MIF, and TRPV1 gene polymorphisms, while CD14 and MIF gene variants are also associated with dyspepsia symptoms burden.

Functional dyspepsia

PURPOSE OF REVIEW

Functional dyspepsia affects 10% of the population. Emerging data are beginning to unravel the pathogenesis of this heterogeneous disorder, and new data on treatment are helping to guide evidence-based practice. In this review, the latest advances are summarized and discussed.

RECENT FINDINGS

The Rome IV criteria were published in 2016 and are similar to Rome III but further emphasize the subtypes (postprandial distress syndrome and epigastric pain syndrome) rather than focussing on the syndrome as a whole, and conclude that gastroesophageal reflux disease and irritable bowel syndrome are part of the functional dyspepsia spectrum. Environment is dominant in the pathogenesis. New data implicate herbivore pets and antibiotic exposure for a nongastrointestinal infection but require confirmation. Further experimental data suggest duodenal eosinophils and mast cells can alter enteric neuronal structure and function in functional dyspepsia.

SUMMARY

Advances in our understanding of functional dyspepsia are changing clinical practice.