Postprandial symptoms in disorders of gut-brain interaction and their potential as a treatment target.

Postprandial, or meal-related, symptoms, such as abdominal pain, early satiation, fullness or bloating, are often reported by patients with disorders of gut-brain interaction, including functional dyspepsia (FD) or irritable bowel syndrome (IBS). We propose that postprandial symptoms arise via a distinct pathophysiological process. A physiological or psychological insult, for example, acute enteric infection, leads to loss of tolerance to a previously tolerated oral food antigen. This enables interaction of both the microbiota and the food antigen itself with the immune system, causing a localised immunological response, with activation of eosinophils and mast cells, and release of inflammatory mediators, including histamine and cytokines. These have more widespread systemic effects, including triggering nociceptive nerves and altering mood. Dietary interventions, including a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols, elimination of potential food antigens or gluten, IgG food sensitivity diets or salicylate restriction may benefit some patients with IBS or FD. This could be because the restriction of these foods or dietary components modulates this pathophysiological process. Similarly, drugs including proton pump inhibitors, histamine-receptor antagonists, mast cell stabilisers or even tricyclic or tetracyclic antidepressants, which have anti-histaminergic actions, all of which are potential treatments for FD and IBS, act on one or more of these mechanisms. It seems unlikely that food antigens driving intestinal immune activation are the entire explanation for postprandial symptoms in FD and IBS. In others, fermentation of intestinal carbohydrates, with gas release altering reflex responses, adverse reactions to food chemicals, central mechanisms or nocebo effects may dominate. However, if the concept that postprandial symptoms arise from food antigens driving an immune response in the gastrointestinal tract in a subset of patients is correct, it is paradigm-shifting, because if the choice of treatment were based on one or more of these therapeutic targets, patient outcomes may be improved.

Alterations in gastrointestinal motility assessed by high-resolution antroduodenal manometry in patients with severe disorders of gut-brain interaction.

Data are limited regarding gastrointestinal motility disturbance in disorders of gut-brain interaction (DGBI). This study aimed to characterize antroduodenal motor alterations in patients with high-resolution antroduodenal manometry (HR-ADM). HR-ADM was performed in patients with severe DGBI and compared with healthy volunteers (HV). HR-ADM used a commercially available probe composed of 36 electronic sensors spaced 1 cm apart and positioned across the pylorus. Antral and duodenal motor high-resolution profiles were analyzed, based on the frequency, amplitude, and contractile integral/sensor (CI/s) calculated for each phase of the migrating motor complex (MMC). Eighteen HV and 64 patients were investigated, 10 with irritable bowel syndrome (IBS), 24 with functional dyspepsia (FD), 15 with overlap IBS-FD, and 15 with other DGBI. Compared with HV, patients had a lower frequency of phase II duodenal contractions (27 vs. 51 per hour; P = 0.002) and a lower duodenal phase II contraction amplitude (70 vs. 100 mmHg; P = 0.01), resulting in a lower CI/s of phase II (833 vs. 1,901 mmHg·cm·s; P < 0.001) in the duodenum. In addition, the frequency of phase II propagated antroduodenal contractions was lower (5 vs. 11 per hour; P < 0.001) in patients compared with HV. Interestingly, the antral CI/s of phase III was decreased in FD patients but not in IBS patients. Patients with severe DGBI display alterations in antral and intestinal motility assessed by commercially available HR-ADM. Whether these alterations may explain symptom profiles in such patients remains to be confirmed (NCT04918329 and NCT01519180).NEW & NOTEWORTHY Gastrointestinal dysmotility has been assessed poorly in disorders of gut-brain interaction (DGBI), especially with high-resolution antroduodenal manometry. Plots of DGBI patients showed lower duodenal contractions during phase II regarding amplitude, frequency, and contractile integral/sensor (CI/s) compared with healthy volunteers. A lower frequency of propagated antroduodenal contractions was also reported. Finally, antral CI/s was lower in patients with functional dyspepsia during phase III. Further studies are needed to assess the clinical significance of these alterations.

Current opinion: functional dyspepsia.

PURPOSE OF REVIEW: Functional dyspepsia is a common gastrointestinal disease that is under-recognized and under-diagnosed. It is a complex disorder of gut-brain interaction with no FDA-approved treatment options. The purpose of this review is to highlight updates in the proposed pathophysiology and present new data regarding potential therapies for functional dyspepsia. RECENT FINDINGS: Alterations in the intestinal microbiome and integrity of the intestinal membrane may play a crucial role in the pathogenesis of functional dyspepsia. The low FODMAP diet, in addition to modulating the microbiome with antibiotics and probiotics, are targets for large future studies. Novel methods of delivery of gut-brain therapies have shown promising results, especially virtual reality. SUMMARY: The pathophysiology and management of functional dyspepsia is complex and there is still much unknown; however, continued research is identifying new targets for treatment. New and more targeted treatment options provide clinicians a variety of tools to offer patients with functional dyspepsia.

Management of abdominal bloating and distension, from subjective to objective.

Abdominal distension is a clinical occurrence that involves a measurable, objective increase in abdominal circumference, which patients report as feeling like pregnant or like having a balloon inside the abdomen. This sign is often preceded by a subjective feeling of abdominal heaviness or bloating, reported as the sensation of having a huge amount of gas trapped inside. These manifestations are highly prevalent and may reflect on their own a gut-brain axis condition, such as functional abdominal distension, or be part of other disorders such as functional dyspepsia or irritable bowel syndrome (IBS). The prevalence of abdominal distension and bloating is 3.5 %. However, when associated with other gut-brain axis disorders such as dyspepsia or IBS, prevalence grows above 50 %. The etiology and pathophysiology of abdominal bloating and distension are highly complex and represent a challenge for both the practitioner and the patient. The patient often associates these sensations with trapped gas, and attributes them to some food intolerance, hence he/she adopts a highly restrictive diet that fails to resolve distension while incurring the risk of nutritional deficiencies or secondary dysbiosis, making a directed treatment guideline necessary.

[Comparative analysis of efficacy of different forms of Galli Gigerii Endothelium Corneum on functional dyspepsia in rats based on composition-pharmacodynamics].

A systematic evaluation of the differences in the chemical composition and efficacy of the different forms of Galli Gigerii Endothelium Corneum(GGEC) was conducted based on modern analytical techniques and a functional dyspepsia(FD) rat model, which clarifies the material basis of the digestive efficacy of GGEC. Proteins, enzymes, polysaccharides, amino acids, and flavonoids in GGEC powder and decoction were determined respectively. The total protein of the powder and decoction was 0.06% and 0.65%, respectively, and the pepsin and amylase potency of the powder was 27.03 and 44.05 U·mg~(-1) respectively. The polysaccharide of the decoction was 0.03%, and there was no polysaccharide detected in the powder. The total L-type amino acids in the powder and decoction were 279.81 and 8.27 mg·g~(-1) respectively, and the total flavonoid content was 59.51 µg·g~(-1). Enzymes and flavonoids were not detected in the decoction. The powder significantly reduced nutrient paste viscosity, while the decoction and control group showed no significant reduction in nutrient paste viscosity. FD rat models were prepared by iodoacetamide gavage and irregular diet. The results showed that both powder and decoction significantly increased the gastric emptying effect, small intestinal propulsion rate, digestive enzymes activity, gastrin(GAS), motilin(MTL), ghrelin(GHRL) and reduced vasoactive intestinal peptide(VIP), 3-(2-ammo-nioethyl)-5-hydroxy-1H-indolium maleate(5-HT), and somatostatin(SST) content in rats(P<0.05, P<0.01). Comparison of GGEC decoction and powder administration between groups of the same dosage level showed that gastrointestinal propulsion and serum levels of GAS, GHRL, VIP, and SST in the powder group were significantly superior to those in the decoction and that the gastrointestinal propulsion, as well as serum levels of MTL, GAS, and GHRL were slightly higher than those of the decoction with two times its raw dose, and the serum levels of SST, 5-HT, and VIP in the powder group were slightly lower than those of the decoction with two times its raw dose. In conclusion, both decoction and powder have therapeutic effects on FD, but there is a significant difference between the two effects. Under the same dosage, the digestive efficacy of the powder is significantly better than that of the decoction, and the decoction needs to increase the dosage to compensate for the efficacy. It is hypothesized that the digestive efficacy of the GGEC has a duality, and the digestive active ingredients of the powder may include enzymes and L-type amino acids, while the decoction mainly relies on L-type amino acids to exert its efficacy. This study provides new evidence to investigate the digestive active substances of the GGEC and to improve the effectiveness of the drug in the clinic.

Comparison of pancreatic enzyme abnormalities and protease-activated receptor-2-positive eosinophils in the duodenum of patients with functional dyspepsia-irritable bowel syndrome overlap with functional dyspepsia alone in Asian populations.

BACKGROUND AND AIM: Some patients with functional gastrointestinal disorders exhibit pancreatic dysfunctions and pancreatic enzyme abnormalities. Thus, we aimed to clarify whether significant differences in clinical characteristics, prevalence of pancreatic enzyme abnormalities, duodenal inflammation, and protease-activated receptor 2 (PAR2) expression levels related to hypersensitivity exist between functional dyspepsia (FD) alone and FD-irritable bowel syndrome (IBS) overlap group. METHODS: Ninety-three patients based on the Rome IV criteria, FD alone (n = 44) and FD overlapped with IBS (n = 49) group were enrolled. The patients scored their own clinical symptoms after consuming high-fat meals. Serum trypsin, PLA2, lipase, p-amylase, and elastase-1 levels were measured. PAR2, eotaxin-3, and TRPV4 mRNA levels in duodenum were determined using real-time polymerase chain reaction methods. PRG2- and PAR2 in the duodenum were evaluated using immunostaining. RESULTS: FD score and global GSRS in patients with FD-IBS overlap were significantly higher than FD alone. Although the prevalence of pancreatic enzyme abnormalities in patients with FD alone was significantly (P < 0.01) higher than that in FD-IBS overlap, the ratio of aggravation of clinical symptoms following high-fat intake in patients with FD-IBS overlap was significantly higher (P = 0.007) than that in patients with FD alone. PAR2- and PRG2-double positive cells were localized in the degranulated eosinophils in the duodenum of patients with FD-IBS overlap. The number of PAR2- and PRG2-double positive cells in FD-IBS overlap was significantly (P < 0.01) higher than FD alone. CONCLUSIONS: Pancreatic enzyme abnormalities and PAR2 expression on degranulated eosinophils infiltrations in the duodenum may be associated with the pathophysiology of patients with FD-IBS overlap in Asian populations.

Functional Dyspepsia and Gastroparesis in Tertiary Care are Interchangeable Syndromes With Common Clinical and Pathologic Features.

BACKGROUND: The aim of this study was to clarify the pathophysiology of functional dyspepsia (FD), a highly prevalent gastrointestinal syndrome, and its relationship with the better-understood syndrome of gastroparesis. METHODS: Adult patients with chronic upper gastrointestinal symptoms were followed up prospectively for 48 weeks in multi-center registry studies. Patients were classified as having gastroparesis if gastric emptying was delayed; if not, they were labeled as having FD if they met Rome III criteria. Study analysis was conducted using analysis of covariance and regression models. RESULTS: Of 944 patients enrolled during a 12-year period, 720 (76%) were in the gastroparesis group and 224 (24%) in the FD group. Baseline clinical characteristics and severity of upper gastrointestinal symptoms were highly similar. The 48-week clinical outcome was also similar but at this time 42% of patients with an initial diagnosis of gastroparesis were reclassified as FD based on gastric-emptying results at this time point; conversely, 37% of patients with FD were reclassified as having gastroparesis. Change in either direction was not associated with any difference in symptom severity changes. Full-thickness biopsies of the stomach showed loss of interstitial cells of Cajal and CD206+ macrophages in both groups compared with obese controls. CONCLUSIONS: A year after initial classification, patients with FD and gastroparesis, as seen in tertiary referral centers at least, are not distinguishable based on clinical and pathologic features or based on assessment of gastric emptying. Gastric-emptying results are labile and do not reliably capture the pathophysiology of clinical symptoms in either condition. FD and gastroparesis are unified by characteristic pathologic features and should be considered as part of the same spectrum of truly "organic" gastric neuromuscular disorders. CLINICALTRIALS. GOV IDENTIFIER: NCT00398801, NCT01696747.

Ultrasonographic assessment of preoperative gastric volume in patients with dyspepsia: a prospective observational study.

BACKGROUND: Patients undergoing gastroenteroscopy during sedation are prone to aspiration, and most patients with dyspepsia have delayed gastric emptying. This study aimed to investigate the feasibility of measuring the gastric antrum cross-sectional area (CSA) to supply a novel clinical diagnostic reference value in patients with dyspepsia. METHODS: Patients with dyspepsia undergoing elective gastroscopy were included. The Perlas qualitative 0-2 grading scale score was determined before the operation. The anteroposterior diameter (D1) and craniocaudal diameter (D2) between gastric antrum serosal surfaces were measured perpendicular to each other in the supine and right lateral decubitus (RLD) positions. CSA values in the supine position and RLD position were determined. Gastric contents were endoscopically suctioned with the volumes measured and noted as actual gastric volume. Multiple regression analysis was used to fit a mathematical model for estimating the gastric volume. Receiver operating characteristic (ROC) curves were constructed to determine the accuracy of RLD CSA to detect gastric volumes of > 0.8 ml/kg. RESULTS: A total of 117 patients were enrolled and divided into a functional dyspepsia (FD) group and an organic dyspepsia group according to gastroscopy findings. For a gastric volume of > 0.8 ml/kg, cut-off values for FD and organic dyspepsia were 6.7 cm2 and 10.0 cm2, respectively. Two new modified mathematical models were derived to predict an estimated gastric volume for FD and organic dyspepsia: volume = 3.93 × RLD CSA - 0.47 × age; and volume = 6.15 × RLD CSA - 0.61 × age. CONCLUSION: We used the cut-off value of the antral area for the fast diagnosis of gastric volumes in patients with dyspepsia, which may assist clinicians in identifying patients at risk of aspiration. TRIAL REGISTRATION: www.chictr.org.cn ( CHICTR-DDD-17010871 ); registered 15 March 2017.

Transcutaneous auricular vagal nerve stimulation improves functional dyspepsia by enhancing vagal efferent activity.

This study was designed to investigate whether transcutaneous auricular vagal nerve stimulation (taVNS) would be able to improve major pathophysiologies of functional dyspepsia (FD) in patients with FD. Thirty-six patients with FD (21 F) were studied in two sessions (taVNS and sham-ES). Physiological measurements, including gastric slow waves, gastric accommodation, and autonomic functions, were assessed by the electrogastrogram (EGG), a nutrient drink test and the spectral analysis of heart rate variability derived from the electrocardiogram (ECG), respectively. Thirty-six patients with FD (25 F) were randomized to receive 2-wk taVNS or sham-ES. The dyspeptic symptom scales, anxiety and depression scores, and the same physiological measurements were assessed at the beginning and the end of the 2-wk treatment. In comparison with sham-ES, acute taVNS improved gastric accommodation (P = 0.008), increased the percentage of normal gastric slow waves (%NSW, fasting: P = 0.010; fed: P = 0.007) and vagal activity (fasting: P = 0.056; fed: P = 0.026). In comparison with baseline, 2-wk taVNS but not sham-ES reduced symptoms of dyspepsia (P = 0.010), decreased the scores of anxiety (P = 0.002) and depression (P < 0.001), and improved gastric accommodation (P < 0.001) and the %NSW (fasting: P < 0.05; fed: P < 0.05) by enhancing vagal efferent activity (fasting: P = 0.015; fed: P = 0.048). Compared with the HC, the patients showed increased anxiety (P < 0.001) and depression (P < 0.001), and decreased gastric accommodation (P < 0.001) and %NSW (P < 0.001) as well as decreased vagal activity (fasting: P = 0.047). The noninvasive taVNS has a therapeutic potential for treating nonsevere FD by improving gastric accommodation and gastric pace-making activity via enhancing vagal activity.NEW & NOTEWORTHY Treatment of functional dyspepsia is difficult due to various pathophysiological factors. The proposed method of transcutaneous auricular vagal nerve stimulation improves symptoms of both dyspepsia and depression/anxiety, and gastric functions (accommodation and slow waves), possibly mediated via the enhancement of vagal efferent activity. This noninvasive and easy-to-implement neuromodulation method will be well received by patients and healthcare providers.

Functional gastrointestinal disorders: advances in understanding and management.

Gastrointestinal symptoms are highly prevalent, but many people who have them will have no organic explanation for their symptoms. Most of these people will be labelled as having a functional gastrointestinal disorder, such as irritable bowel syndrome, functional dyspepsia, or functional constipation. These conditions affect up to 40% of people at any one point in time, and two-thirds of these people will have chronic, fluctuating symptoms. The pathophysiology of functional gastrointestinal disorders is complex, but involves bidirectional dysregulation of gut-brain interaction (via the gut-brain axis), as well as microbial dysbiosis within the gut, altered mucosal immune function, visceral hypersensitivity, and abnormal gastrointestinal motility. Hence, nomenclature refers to the conditions as disorders of gut-brain interaction. Psychological comorbidity is common; however, whether or not this predates, or is driven by, symptoms is not clear. Patients with functional gastrointestinal disorders can feel stigmatised, and often this diagnosis is not communicated effectively by physicians, nor is education provided. Prompt identification and treatment of these conditions is crucial as they have a considerable impact on health-care systems and society as a whole because of repeated consultations, unnecessary investigations and surgeries, prescriptions and over-the-counter medicine use, and impaired health-related quality of life and ability to work. Symptom-based criteria are used to make a diagnosis, with judicious use of limited investigations in some patients. The general principles of treatment are based on a biopsychosocial understanding and involve management of physical symptoms and, if present, psychological comorbidity. In the future, treatment approaches to functional gastrointestinal disorders are likely to become more personalised, based not only on symptoms but also underlying pathophysiology and psychology.

Functional dyspepsia.

Dyspepsia is a complex of symptoms referable to the gastroduodenal region of the gastrointestinal tract and includes epigastric pain or burning, postprandial fullness, or early satiety. Approximately 80% of individuals with dyspepsia have no structural explanation for their symptoms and have functional dyspepsia. Functional dyspepsia affects up to 16% of otherwise healthy individuals in the general population. Risk factors include psychological comorbidity, acute gastroenteritis, female sex, smoking, use of non-steroidal anti-inflammatory drugs, and Helicobacter pylori infection. The pathophysiology remains incompletely understood, but it is probably related to disordered communication between the gut and the brain, leading to motility disturbances, visceral hypersensitivity, and alterations in gastrointestinal microbiota, mucosal and immune function, and CNS processing. Although technically a normal endoscopy is required to diagnose functional dyspepsia, the utility of endoscopy in all patients with typical symptoms is minimal; its use should be restricted to people aged 55 years and older, or to those with concerning features, such as weight loss or vomiting. As a result of our incomplete understanding of its pathophysiology, functional dyspepsia is difficult to treat and, in most patients, the condition is chronic and the natural history is one of fluctuating symptoms. Eradication therapy should be offered to patients with functional dyspepsia who test positive for Helicobacter pylori. Other therapies with evidence of effectiveness include proton pump inhibitors, histamine-2 receptor antagonists, prokinetics, and central neuromodulators. The role of psychological therapies is uncertain. As our understanding of the pathophysiology of functional dyspepsia increases, it is probable that the next decade will see the emergence of truly disease-modifying therapies for the first time.

Nutrient Drinking Test as Biomarker in Functional Dyspepsia.

INTRODUCTION: Functional dyspepsia (FD) is a prevalent condition with multifactorial pathophysiology, including impaired gastric accommodation (GA), hypersensitivity to gastric distention, and delayed gastric emptying. Drink tests (DT) have been proposed as a potential biomarker for the presence and severity of gastric sensorimotor dysfunction. Thus, we aimed to summarize the state of knowledge on different DT and their potential as a biomarker for FD. METHODS: A PubMed and MEDLINE search was conducted for English language articles, reviews, meta-analyses, case series, and randomized controlled trials, including also published meeting abstracts. RESULTS: Several DT have been described in literature (e.g., different type of liquid, number of calories used, pace of drinking, and subject's awareness of the amount of liquid drunk). FD patients ingest significantly less volume in the different variants of the tests. The slow nutrient ("satiety drinking") test (SDT) studies show the most consistent separation between health and FD and correlation with GA. However, sensitivity to distention may be correlated with rapid DT. SDTs were used to evaluate the effect of several pharmacological agents, often showing concordance between their effects on GA and tolerated nutrient volume. This correlation was not found mainly for agents with central actions. DISCUSSION: An SDT is a potential diagnostic biomarker in FD, reflecting GA. Additional studies are required to confirm its role as a predictive biomarker for treatment outcome in FD.

The rodent model of impaired gastric motility induced by allyl isothiocyanate, a pungent ingredient of wasabi, to evaluate therapeutic agents for functional dyspepsia.

Functional dyspepsia (FD) is thought to be mainly based on gastric motility dysfunction and chronic hypersensitivity, yet FD animal models has been reported a few. We studied to establish the mouse model of impaired gastric motility induced by a pungent ingredient of wasabi allyl isothiocyanate (AITC), which is reliable to evaluate prokinetic agents. Male ddY mice were used. Gastric motility was measured by 13C-acetic acid breath test in conscious mice. AITC (80 mM) was given 60 min before the measurement of motility. Prokinetic agents including itopride (30, 100 mg/kg), mosapride (0.1-1 mg/kg), neostigmine (30 µg/kg), acotiamide (10-100 mg/kg), and daikenchuto (100-1000 mg/kg) were given 40 min before the measurement. AITC impaired gastric motility without mucosal damages, which reverted 24 h after AITC treatment. The decreased motility induced by AITC was restored by prokinetic agents such as itopride, mosapride, neostigmine, and acotiamide. In separate experiment, daikenchuto recovered the decreased motility induced by AITC, although daikenchuto had no effect on motility in normal condition. In conclusion, it is considered that the AITC-induced impaired gastric motility mouse model is useful to develop new prokinetic agents for treatment of FD, and to re-evaluate traditional Japanese herbal medicines.

Functional dyspepsia in children: A study of pathophysiological factors.

BACKGROUND AND AIM: Functional dyspepsia (FD) is common in children, and treatment targeted towards the altered pathophysiology can improve outcome. We evaluated FD children for abnormality of gastric accommodation and emptying, psychological stressors (PS), Helicobacter pylori (HP) infection, and post-infectious FD. METHODS: Diagnosis of FD was based on ROME III criteria. Clinical evaluation including dyspeptic symptom scoring and assessment for PS was performed. Satiety drink test for gastric accommodation, gastroscopy with biopsy for HP infection, and solid meal gastric emptying were performed. Sixty-seven healthy children were enrolled for assessing PS and satiety drink test. RESULTS: Fifty-five FD children (33 boys, age 12 [6-18] years) with symptoms for 4 (2-48) months and dyspeptic score of 5 (1-13) were enrolled. PS were more common in FD than in controls (46/55 vs 9/67; P < 0.001). Median satiety drink volume was 360 mL (180-1320 mL); no patients had satiety drink volume of < 5th centile of healthy children. The frequency (98% vs 85%; P = 0.01) and severity (65 [10-175] vs 50 [5-130]; P < 0.001) of postprandial symptoms were higher in FD than in controls. Of the postprandial symptoms, pain (20.3% vs 0%; P = 0.000) was present only in FD. Delayed gastric emptying was present in 6.5%, HP infection in 11%, and post-infectious FD in 13% cases. Etiological factor was identified in 87% children, with 20% having multiple factors. CONCLUSIONS: Abnormality of gastric sensorimotor function is seen in one-fourth of FD cases. HP infection and post-infectious FD are present in 11% and 13% cases, respectively.

Effect of Acupuncture for Postprandial Distress Syndrome: A Randomized Clinical Trial.

BACKGROUND: Postprandial distress syndrome (PDS) is the most common subtype of functional dyspepsia. Acupuncture is commonly used to treat PDS, but its effect is uncertain because of the poor quality of prior studies. OBJECTIVE: To assess the efficacy of acupuncture versus sham acupuncture in patients with PDS. DESIGN: Multicenter, 2-group, randomized clinical trial. (ISRCTN registry number: ISRCTN12511434). SETTING: 5 tertiary hospitals in China. PARTICIPANTS: Chinese patients aged 18 to 65 years meeting Rome IV criteria for PDS. INTERVENTION: 12 sessions of acupuncture or sham acupuncture over 4 weeks. MEASUREMENTS: The 2 primary outcomes were the response rate based on overall treatment effect and the elimination rate of all 3 cardinal symptoms: postprandial fullness, upper abdominal bloating, and early satiation after 4 weeks of treatment. Participants were followed until week 16. RESULTS: Among the 278 randomly assigned participants, 228 (82%) completed outcome measurements at week 16. The estimated response rate from generalized linear mixed models at week 4 was 83.0% in the acupuncture group versus 51.6% in the sham acupuncture group (difference, 31.4 percentage points [95% CI, 20.3 to 42.5 percentage points]; P < 0.001). The estimated elimination rate of all 3 cardinal symptoms was 27.8% in the acupuncture group versus 17.3% in the sham acupuncture group (difference, 10.5 percentage points [CI, 0.08 to 20.9 percentage points]; P = 0.034). The efficacy of acupuncture was maintained during the 12-week posttreatment follow-up. There were no serious adverse events. LIMITATION: Lack of objective outcomes and daily measurement, high dropout rate, and inability to blind acupuncturists. CONCLUSION: Among patients with PDS, acupuncture resulted in increased response rate and elimination rate of all 3 cardinal symptoms compared with sham acupuncture, with sustained efficacy over 12 weeks in patients who received thrice-weekly acupuncture for 4 weeks. PRIMARY FUNDING SOURCE: Beijing Municipal Science and Technology Commission.

Novel concepts in the pathophysiology and treatment of functional dyspepsia.

Emerging data increasingly point towards the duodenum as a key region underlying the pathophysiology of functional dyspepsia (FD), one of the most prevalent functional GI disorders. The duodenum plays a major role in the control and coordination of gastroduodenal function. Impaired duodenal mucosal integrity and low-grade inflammation have been associated with altered neuronal signalling and systemic immune activation, and these alterations may ultimately lead to dyspeptic symptoms. Likely luminal candidates inducing the duodenal barrier defect include acid, bile, the microbiota and food antigens although no causal association with symptoms has been convincingly demonstrated. Recognition of duodenal pathology in FD will hopefully lead to the discovery of new biomarkers and therapeutic targets, allowing biologically targeted rather than symptom-based therapy. In this review, we summarise the recent advances in the diagnosis and treatment of FD with a focus on the duodenum.

Effects of electroacupuncture on stress-induced gastric dysrhythmia and mechanisms involving autonomic and central nervous systems in functional dyspepsia.

Electroacupuncture (EA) is widely used as an effective method to treat stress-related disorders. However, its mechanisms remain largely unknown. The aim of this study was to investigate the effects and mechanisms of EA on gastric slow wave (GSW) dysrhythmia and c-Fos expression in the nucleus of the solitary tract (NTS) induced by stress in a rodent model of functional dyspepsia (FD). Rats in the neonatal stage were treated using intragastric iodoacetamide. Eight weeks later, the rats were implanted with electrodes in the stomach for the measurement of GSW and electrodes into accupoints ST36 for EA. Autonomic functions were assessed by spectral analysis of heart rate variability. Rats were placed for 30 min in a cylindrical plastic tube for acute restraint stress. The involvement of a central afferent pathway was assessed by measuring c-Fos-immunoreactive cells in the NTS. 1) EA normalized restraint stress-induced impairment of GSW in FD rats. 2) EA significantly increased vagal activity (P = 0.002) and improved sympathovagal balance (P = 0.004) under stress in FD rats. 3) In FD rats under restraint stress, plasma norepinephrine concentration was increased substantially (P < 0.01), which was suppressed with EA. 4) The EA group showed increased c-Fos-positive cell counts in the NTS compared with the sham EA group (P < 0.05) in FD rats. Acute restraint stress induces gastric dysrhythmia in a rodent model of FD. EA at ST36 improves GSW under stress in FD rats mediated via the central and autonomic pathways, involving the NTS and vagal efferent pathway.

Exploration of the mechanism of traditional Chinese medicine by AI approach using unsupervised machine learning for cellular functional similarity of compounds in heterogeneous networks, XiaoErFuPi granules as an example.

'Polypharmacology' is usually used to describe the network-wide effect of a single compound, but traditional Chinese medicine (TCM) has a polypharmacological effect naturally based on the 'multi-components, multi-targets and multi-pathways' principle. It is a challenge to investigate the polypharmacology mechanism of TCM with multiple components. In this study, we used XiaoErFuPi (XEFP) granules as an example to describe an unsupervised learning strategy for polypharmacology research of TCM and to explore the mechanism of XEFP polypharmacology against multifactorial disease function dyspepsia (FD). Unsupervised clustering of compounds based on similarity evaluation of cellular function fingerprints showed that compounds of TCM without similar targets and chemical structure could also exert similar therapeutic effects on the same disease, as different targets participate in the same pathway closely associated with the pathological process. In this study, we proposed an unsupervised machine learning strategy for exploring the polypharmacology-based mechanism of TCM, utilizing hierarchical clustering based on cellular functional similarity, to establish a connection from the chemical clustering module to cellular function. Meanwhile, FDA-approved drugs against FD were used as references for the mechanism of action (MoA) of FD. First, according to the compound-compound network built by the similarity of cellular function of XEFP compounds and FDA-approved FD drugs, the possible therapeutic function of TCM may represent a known mechanism of FDA-approved drugs. Then, as unsupervised learning, hierarchical clustering of TCM compounds based on cellular function fingerprint similarity could help to classify the compounds into several modules with similar therapeutic functions to investigate the polypharmacology effect of TCM. Furthermore, the integration of quantitative omics data of TCM and approved drugs (from LINCS datasets) provides more quantitative evidence for TCM therapeutic function consistency with approved drugs. A spasmolytic activity experiment was launched to confirm vanillic acid activity to repress smooth muscle contraction; vanillic acid was also predicted to be active compound of XEFP, supporting the accuracy of our strategy. In summary, the approach proposed in this study provides a new unsupervised learning strategy for polypharmacological research investigating TCM by establishing a connection between the compound functional module and drug-activated cellular processes shared with FDA-approved drugs, which may elucidate the unique mechanism of traditional medicine using FDA-approved drugs as references, facilitate the discovery of potential active compounds of TCM and provide new insights into complex diseases.

Gastroparesis versus dyspepsia by intragastric meal distribution: new diagnostics and definitions ahead.

Gastroparesis often presents a challenge to the practicing gastroenterologist. Postprandial symptoms with nausea and vomiting may not only lead to nutritional and metabolic consequences, but also significant disruption of social activities that often center around food. The treatment options that affect gastric function are limited and often disappointing. The female predominance, the mostly idiopathic and idiosyncratic nature of the illness, often with some common psychiatric co-morbidity, parallels other functional disorders of the gastrointestinal tract. These parallels have provided the rationale for studies investigating alternative diagnostic features of the gastric emptying test as employed in the clinical setting. Hence, not only the regular cut-offs of 60% or 10% gastric retention of a meal at 2 and 4 h, but also a new concept, the intragastric meal distribution at time 0 (IMD0) is now introduced as a plausible diagnostic feature that should be more aligned with the patients' symptoms as they appear in close connection with the meal. Impaired gastric accommodation with absence of fundic relaxation followed by dumping of the meal into antrum is suggested to be diagnostic for functional dyspepsia and gastroparesis. The diagnostic cut-off is considered when more than 57% of the meal is distributed to the distal part of the stomach immediately on food intake. This new diagnostic feature of the gastric emptying profile lend support to better understanding of the patients' symptoms and provides a new basis for pharmacological treatment options in gastroparesis that may provide an improved quality of life in affected individuals.

A cross-sectional study of nausea in functional abdominal pain: relation to mucosal mast cells and psychological functioning.

BACKGROUND: Nausea is a common symptom in youth with chronic abdominal pain. The aims of the current study were to assess: 1) the frequency of nausea in patients with functional dyspepsia (FD) and irritable bowel syndrome (IBS), respectively, as defined by Rome IV criteria; and, 2) relationships between nausea and mucosal inflammation as defined by antral and duodenal eosinophil and mast cell densities. A secondary aim was to assess relationships between nausea and other gastrointestinal symptoms, non-gastrointestinal somatic symptoms, and psychological dysfunction. METHODS: Records from patients with pain associated functional gastrointestinal disorders were retrospectively reviewed for gastrointestinal and somatic symptoms and anxiety, depression, and somatizations scores as assessed by the Behavior Assessment System for Children (BASC-2). In addition, previous gastric and mucosal biopsies were assessed for mast cell and eosinophil densities, respectively. RESULTS: 250 patients, ages 8 to 17 years, were assessed. Nausea was reported by 78% and was equally prevalent in those with FD alone, those with IBS alone, and those with both FD and IBS. Nausea was associated with increased mean (21.4 vs. 17.5) and peak (26.2 vs. 22.9) duodenal mast cell densities as compared those without nausea. Nausea was also associated with a wide variety of individual gastrointestinal symptoms, as well as headaches, fatigue, and dizziness. Lastly, nausea was associated with elevated self-report scores for anxiety (55.2 vs. 50.0), depression (50.2 vs. 46.1), and somatization (70.3 vs. 61.8). CONCLUSIONS: Nausea is common in children and adolescents with pain-associated FGIDs as defined by Rome IV and is not unique to either FD or IBS. Nausea is associated with increased mucosal mast cell density, non-gastrointestinal somatic symptoms, and psychologic dysfunction.