Drugs under development for the treatment of functional dyspepsia and related disorders

Dopamine Receptors and TAAR1 Functional Interaction Patterns in the Duodenum Are Impaired in Gastrointestinal Disorders

Currently, there is a growing amount of evidence for the involvement of dopamine receptors and the functionally related trace amine-associated receptor, TAAR1, in upper intestinal function. In the present study, we analyzed their expression in the duodenum using publicly accessible transcriptomic data. We revealed the expression of DRD1, DRD2, DRD4, DRD5, and TAAR1 genes in different available datasets. The results of the gene ontology (GO) enrichment analysis for DRD2 and especially TAAR1 co-expressed genes were consistent with the previously described localization of D2 and TAAR1 in enteric neurons and secretory cells, respectively. Considering that co-expressed genes are more likely to be involved in the same biological processes, we analyzed genes that are co-expressed with TAAR1, DRD2, DRD4, and DRD5 genes in healthy mucosa and duodenal samples from patients with functional dyspepsia (FD) or diabetes-associated gastrointestinal symptoms. Both pathological conditions showed a deregulation of co-expression patterns, with a high discrepancy between DRDs and TAAR1 co-expressed gene sets in normal tissues and patients' samples and a loss of these genes' functional similarity. Meanwhile, we discovered specific changes in co-expression patterns that may suggest the involvement of TAAR1 and D5 receptors in pathologic or compensatory processes in FD or diabetes accordingly. Despite our findings suggesting the possible role of TAAR1 and dopamine receptors in functional diseases of the upper intestine, underlying mechanisms need experimental exploration and validation.

Targeting the altered duodenal microenvironment in functional dyspepsia

Duodenal micro-inflammation and microbial dysregulation are increasingly recognized to play an important role in functional dyspepsia (FD) pathophysiology, previously regarded as a purely functional disorder. With current therapeutic options contested through insufficient efficacy or unfavorable adverse effects profiles, novel treatments directed to duodenal alterations could result in superior symptom control in at least a subset of patients. Indeed, recent advances in FD research provided evidence for anti-inflammatory therapies to relieve gastroduodenal symptoms by reducing duodenal eosinophils or mast cells. In addition, restoring microbial homeostasis by probiotics proved to be successful in FD. As the exact mechanisms by which these novel pharmacological approaches result in clinical benefit often remain to be elucidated, future research should focus on how immune activation and dysbiosis translate into typical FD symptomatology.

Neural Responses of Acupuncture for Treating Functional Dyspepsia: An fMRI Study

Different acupoints exhibiting similar therapeutic effects are a common phenomenon in acupuncture clinical practice. However, the mechanism underlying this phenomenon remains unclear. This study aimed to investigate the similarities and differences in cerebral activities elicited through stimulation of CV12 and ST36, the two most commonly used acupoints, in the treatment of gastrointestinal diseases, so as to partly explore the mechanism of the different acupoints with similar effects. Thirty-eight eligible functional dyspepsia (FD) patients were randomly assigned into either group A (CV12 group) or group B (ST36 group). Each patient received five acupuncture treatments per week for 4 weeks. The Symptom Index of Dyspepsia (SID), Nepean Dyspepsia Symptom Index (NDSI), and Nepean Dyspepsia Life Quality Index (NDLQI) were used to assess treatment efficacy. Functional MRI (fMRI) scans were performed to detect cerebral activity changes at baseline and at the end of the treatment. The results demonstrated that (1) improvements in NDSI, SID, and NDLQI were found in both group A and group B (p < 0.05). However, there were no significant differences in the improvements of the SID, NDSI, and NDLQI scores between group A and group B (p > 0.05); (2) all FD patients showed significantly increased amplitude of low-frequency fluctuation (ALFF) in the left postcentral gyrus after acupuncture treatment, and the changes of ALFF in the left postcentral gyrus were significantly related to the improvements of SID scores (r = 0.358, p = 0.041); and (3) needling at CV12 significantly decreased the resting-state functional connectivity (rsFC) between the left postcentral gyrus and angular gyrus, caudate, middle frontal gyrus (MFG), and cerebellum, while needling at ST36 significantly increased the rsFC between the left postcentral gyrus with the precuneus, superior frontal gyrus (SFG), and MFG. The results indicated that CV12 and ST36 shared similar therapeutic effects for dyspepsia, with common modulation on the activity of the postcentral gyrus in FD patients. However, the modulatory pattern on the functional connectivity of the postcentral gyrus was different. Namely, stimulation of CV12 primarily involved the postcentral gyrus–reward network, while stimulation of ST36 primarily involved the postcentral gyrus–default mode network circuitry.

Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect

Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.

The effectiveness of acupoint herbal patching for functional dyspepsia: A protocol for systematic review and meta-analysis

BACKGROUND

Functional dyspepsia (FD) has gradually developed into a multiple disease of the digestive system that most patients may be accompanied by mental and emotional disorders, such as insomnia, anxiety, and depression. Acupoint herbal patching (AHP) is usually used as an alternative therapy for patients with FD. This study aimed to design a systematic review and meta-analysis to explore the effects of AHP on FD.

METHODS

We will search the Cochrane Central Register of Controlled Trials, the Web of Science, PubMed, Embase, the Chinese Biomedical Literature Database, the Chinese Scientific Journal Database, the Wan-Fang Database, and the China National Knowledge Infrastructure for randomized controlled trials of FD treated by AHP from inception to June 30, 2021. The primary outcome measures contain clinical effective rate, the symptom score of FD, and secondary outcome measures consist of quality of life, incidence of adverse events, and recurrence rate. We will use RevMan V.5.3 software to analyze data. Two reviewers will evaluate the risk of bias and the quality of the studies by the Cochrane Collaboration risk of bias tool and the Grading of Recommendations Assessment, Development, and Evaluation approach, separately.

RESULTS

This systematic review protocol will analyze the effectiveness, quality of life, improvement of the symptom, and safety of AHP therapy for FD.

CONCLUSION

The findings of this systematic review will provide evidence to evaluate the effectiveness and safety of AHP for FD.

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

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Mfge8 attenuates human gastric antrum smooth muscle contractions

Coordinated gastric smooth muscle contraction is critical for proper digestion and is adversely affected by a number of gastric motility disorders. In this study we report that the secreted protein Mfge8 (milk fat globule-EGF factor 8) inhibits the contractile responses of human gastric antrum muscles to cholinergic stimuli by reducing the inhibitory phosphorylation of the MYPT1 (myosin phosphatase-targeting subunit (1) subunit of MLCP (myosin light chain phosphatase), resulting in reduced LC20 (smooth muscle myosin regulatory light chain (2) phosphorylation. Mfge8 reduced the agonist-induced increase in the F-actin/G-actin ratios of β-actin and γ-actin1. We show that endogenous Mfge8 is bound to its receptor, α8β1 integrin, in human gastric antrum muscles, suggesting that human gastric antrum muscle mechanical responses are regulated by Mfge8. The regulation of gastric antrum smooth muscles by Mfge8 and α8 integrin functions as a brake on gastric antrum mechanical activities. Further studies of the role of Mfge8 and α8 integrin in regulating gastric antrum function will likely reveal additional novel aspects of gastric smooth muscle motility mechanisms.

Risk factors associated with functional dyspepsia in Chinese children: a cross-sectional study

Background

There is no study assessing the risk factors associated with functional dyspepsia (FD) in Chinese children based on the Rome IV criteria.

Methods

In this cross-sectional study, we analyzed data from eight representative primary and secondary schools to assess the risk factors associated with FD in Chinese children based on the Rome IV criteria.

Results

A total of 6976 Chinese children were enrolled. The mean age was 14.3 ± 2.5 years, with a range from 7 to 17 years, and 3497 (50.1%) participants were female. FD was prevalent in 209 (3.0%) of the Chinese child population studied. Age (OR = 1.112, P = 0.006), living independent of parents (OR = 1.677, P < 0.001), prolonged school meals (OR = 2.107, P < 0.001), never eat breakfast (OR = 2.192, P = 0.003), often/daily eat cold foods (OR = 2.296, P = 0.002; OR = 2.736, P = 0.011), and often eat pickled foods (OR = 2.390, P = 0.001) were found to be independent risk factors for FD. A nomogram with these risk factors had good discrimination (AUC = 0.727) and calibration (Hosmer–Lemeshow test was 0.851).

Conclusions

Age, living independent of parents, prolonged school meals, never eat breakfast, often/daily eat cold foods and often eat pickled foods were independent risk factors for FD. The nomogram could be used as a quick screening tool to assess FD in Chinese children.

Management of Dyspepsia and Gastroparesis in Patients with Diabetes. A Clinical Point of View in the Year 2021

Diabetes mellitus is a widespread disease, and represents an important public health burden worldwide. Together with cardiovascular, renal and neurological complications, many patients with diabetes present with gastrointestinal symptoms, which configure the so-called diabetic enteropathy. In this review, we will focus on upper gastrointestinal symptoms in patients with diabetes, with particular attention to dyspepsia and diabetic gastroparesis (DG). These two clinical entities share similar pathogenetic mechanisms, which include autonomic neuropathy, alterations in enteric nervous system and histological abnormalities, such as interstitial cells of Cajal depletion. Moreover, the differential diagnosis may be challenging because of overlapping clinical features. Delayed gastric emptying should be documented to differentiate between DG and dyspepsia and it can be assessed through radioactive or non-radioactive methods. The clinical management of dyspepsia includes a wide range of different approaches, above all Helicobacter pylori test and treat. As regards DG treatment, a central role is played by dietary modification and glucose control and the first-line pharmacological therapy is represented by the use of prokinetics. A minority of patients with DG refractory to medical treatment may require more invasive therapeutic approaches, including supplemental nutrition, gastric electric stimulation, pyloromyotomy and gastrectomy.

The trimebutine effect on Helicobacter pylori-related gastrointestinal tract and brain disorders: A hypothesis

The localization of bacterial components and/or metabolites in the central nervous system may elicit neuroinflammation and/or neurodegeneration. Helicobacter pylori (a non-commensal symbiotic gastrointestinal pathogen) infection and its related metabolic syndrome have been implicated in the pathogenesis of gastrointestinal tract and central nervous system disorders, thus medications affecting the nervous system - gastrointestinal tract may shape the potential of Helicobacter pylori infection to trigger these pathologies. Helicobacter pylori associated metabolic syndrome, by impairing gut motility and promoting bacterial overgrowth and translocation, might lead to brain pathologies. Trimebutine maleate is a prokinetic drug that hastens gastric emptying, by inducing the release of gastrointestinal agents such as motilin and gastrin. Likewise, it appears to protect against inflammatory signal pathways, involved in inflammatory disorders including brain pathologies. Trimebutine maleate also acts as an antimicrobial agent and exerts opioid agonist effect. This study aimed to investigate a hypothesis regarding the recent advances in exploring the potential role of gastrointestinal tract microbiota dysbiosis-related metabolic syndrome and Helicobacter pylori in the pathogenesis of gastrointestinal tract and brain diseases. We hereby proposed a possible neuroprotective role for trimebutine maleate by altering the dynamics of the gut-brain axis interaction, thus suggesting an additional effect of trimebutine maleate on Helicobacter pylori eradication regimens against these pathologies.

Effect of Artemisia rupestris L. Extract on Gastrointestinal Hormones and Brain-Gut Peptides in Functional Dyspepsia Rats

Artemisia rupestris L. is the perennial herb of rupestris belonging to Artemisia (Compositae), which is wildly distributed in Xinjiang (China), middle Asia, and Europe. It is known to have anti-inflammatory, hepatoprotective, immune function regulation, and gastrointestinal function regulation effects. AR is used to treat digestive diseases, but the effects of AR on antifunctional dyspepsia (FD) activity have not yet been reported. In this study, we aimed to investigate the therapeutic effects of Artemisia rupestris L. extract (ARE) on gastrointestinal hormones and brain-gut peptide in functional dyspepsia (FD) rats. Sixty Sprague-Dawley rats were randomly divided into 6 groups. An FD rat model was established by irregular tail clamp stimulation for 14 days except the blank group. After FD rat models, the blank group and model group were given menstruum, and the medicated rats were given corresponding medicine for 14 days. The general observations, bodyweight, and food intake were observed, and the content of serum gastrin (GAS), plasma motilin (MTL), plasma vasoactive intestinal peptide (VIP), and plasma somatostatin (SS) by the enzyme-linked immunosorbent assay was observed. The content of plasma VIP and plasma SS in the ARE group was significantly lower than in the model group, and the content of serum GAS and plasma MTL was increased in the ARE group; the GAS expression of antrum and hypothalamus was increased in the ARE group, and SS expression of antrum and hypothalamus was decreased in the ARE group by immunohistochemical detection; the results of semiquantitative reverse transcription polymerase chain reaction (RT-PCR) indicate that ARE inhibits the mRNA expression of VIP. Our results suggest that ARE can recover gastrointestinal hormone levels and regulation of the peripheral and central nervous system and alter gut peptide levels, which confirm the therapeutic effect of ARE on functional dyspepsia.

Rome III, Rome IV, and Potential Asia Symptom Criteria for Functional Dyspepsia Do Not Reliably Distinguish Functional From Organic Disease

INTRODUCTION

Although the Rome criteria were created primarily for research purposes, it was an important question whether the Rome criteria can distinguish organic dyspepsia from functional dyspepsia (FD). We evaluated the accuracy of the Rome IV criteria in identifying patients with FD and compared the differences between the Rome IV, Rome III, and potential Asia criteria in identifying patients with FD.

METHODS

In this cross-sectional study, we analyzed data from patients who met the inclusion and exclusion criteria from March 2018 to January 2019 at 2 tertiary hospitals.

RESULTS

A total of 600 patients were enrolled in this study, including 381 individuals met the Rome IV criteria for FD, 438 individuals met the Rome III criteria for FD, and 525 individuals met the potential Asia criteria for FD. The Rome IV criteria identified patients with FD with 67.3% sensitivity and 38.4% specificity, and the positive and negative likelihood ratios of FD identified by Rome IV criteria were 1.09 (95% confidence interval 0.97-1.24) and 0.85 (95% confidence interval 0.67-1.08), respectively. There was no significant difference in the area under Rome IV, Rome III, or potential Asia criteria receiver operating characteristic curves in identifying FD (P > 0.05).

DISCUSSION

The Rome IV criteria were no better than the Rome III or potential Asia criteria in identifying FD and were not helpful in identifying patients with FD. Hence, although the Rome criteria remain useful for defining patients with FD for inclusion into clinical treatment trials, they should not be used for diagnosing FD.

Current and emerging therapeutic options for the management of functional dyspepsia

Introduction: Functional Dyspepsia (FD), defined as chronic symptoms originating from the gastroduodenal region in absence of readily identifiable organic disease, is one of the most common gastrointestinal disorders. FD is divided into two subgroups: Post-Prandial Distress Syndrome (PDS) or meal-related FD, characterized by postprandial fullness and early satiation, and Epigastric Pain Syndrome (EPS) or meal-unrelated FD, characterized by epigastric pain and burning.Areas covered: This review summarizes the existing and off-label therapeutic options for FD.Expert opinion: The identification of mechanisms, the Rome IV classification, the reduction of PDS/EPS overlap and pictograms for symptom identification allow a better diagnosis and a more targeted treatment choice. Acotiamide, a first-in-class prokinetic agent available only in Japan and India, is the only agent of proven efficacy for FD, but clinicians use acid-suppressive therapy, prokinetics, neuromodulators and herbal therapies for treating FD symptoms. New emerging targets are duodenal low-grade inflammation with eosinophils and duodenal or other modified luminal microbiota.