Gastric Activity and Gut Peptides in Patients With Functional Dyspepsia: Postprandial Distress Syndrome Versus Epigastric Pain Syndrome

The Overlap Subgroup of Functional Dyspepsia Exhibits More Severely Impaired Gastric and Autonomic Functions

GOALS

A combination of multiple tests was introduced to noninvasively investigate the differences in pathophysiologies among functional dyspepsia (FD) subgroups, including postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), and overlap.

BACKGROUND

It has not been extensively evaluated whether different pathophysiologies are involved in FD subgroups.

STUDY

This multicenter study included 364 FD patients fulfilling Rome IV criteria and 47 healthy controls. A combined noninvasive gastric and autonomic function test was performed: The electrogastrogram and electrocardiogram were recorded simultaneously in the fasting state and after a drink test. Symptoms after drinking were recorded using visual analog scale.

RESULTS

(1) Compared with HC, FD patients showed a decreased maximum tolerable volume (MTV) ( P <0.01) and percentage of normal gastric slow waves [normal gastric slow waves (%NSW)] ( P <0.01), and increased postdrinking symptoms, anxiety ( P <0.01), and depression ( P <0.01). The drink reduced %NSW in both FD patients and HC; however, the effect was more potent in patients. (2) The PDS and overlap groups displayed a reduced MTV ( P <0.05). The overlap group exhibited a higher symptom score at 30 minutes after drinking, and higher anxiety and depression scores, and a higher sympathovagal ratio than the EPS ( P <0.05 for all) and PDS ( P <0.01 for all). (3) In the PDS subgroup, the MTV, postprandial sympathovagal ratio, and depression were associated with the overall dyspepsia symptom scale (DSS, P =0.034, 0.021, 0.043, respectively). No significant associations were found in the other 2 subgroups.

CONCLUSIONS

The combination of multiple tests can detect pathophysiological abnormities in FD patients. Overall, patients with overlap symptoms display more severe pathophysiologies.

Neurotensin Gene rs2234762 C>G Variant Associates with Reduced Circulating Pro-NT Levels and Predicts Lower Insulin Resistance in Overweight/Obese Children

Neurotensin (NT) is a small protein implicated in the regulation of energy balance which acts as both a neurotransmitter in the central nervous system and as a gastrointestinal peptide. In the gut, NT is secreted after fat ingestion and promotes the absorption of fatty acids. The circulating levels of its precursor, pro-NT, predicts the presence and development of metabolic and cardiovascular diseases. Despite the extensive knowledge on the dynamic changes that occur to pro-NT = after fat load, the determinants of fasting pro-NT are unknown. The aim of this study was to determine the possible genetic regulation of plasma pro-NT. The NT gene (NTS) was sequenced for potential functional variants, evaluating its entire genomic and potentially regulatory regions, in DNA from 28 individuals, stratified by low and high pro-NT levels. The identified variant differently distributed in the two pro-NT subgroups was genotyped in a cohort of nine hundred and thirty-two overweight/obese children and adolescents. A total of seven sequence variations across the NTS gene, none of them located in coding regions, were identified. The rs2234762 polymorphism, sited in the NTS gene promoter, was statistically more frequent in the lowest pro-NTS level group. Carriers of the rs2234762 variant showed lower pro-NT levels, after adjusting for sex, age, BMI, triglycerides and the Tanner stage. Having NTS rs2234762 predicted less pronounced insulin resistance at the 6.5-year follow-up with OR: 0.46 (0.216–0.983), at the logistic regression analysis adjusted for age, sex and BMI. In conclusion, the NTS rs2234762 gene variant is a determinant of reduced circulating pro-NT levels in overweight and obese children, which predisposes this group to a more favorable metabolic profile and a reduced insulin resistance later in life, independently from metabolic confounders.

Clinical associations of functional dyspepsia with gastric dysrhythmia on electrogastrography: A comprehensive systematic review and meta-analysis

BACKGROUND

Functional dyspepsia (FD) is a common gastroduodenal disorder, yet its pathophysiology remains poorly understood. Bioelectrical gastric slow-wave abnormalities are thought to contribute to its multifactorial pathophysiology. Electrogastrography (EGG) has been used to record gastric electrical activity; however, the clinical associations require further evaluation.

AIMS

This study aimed to systematically assess the clinical associations of EGG in FD.

METHODS

MEDLINE, EMBASE, and CENTRAL databases were systematically searched for articles using EGG in adults with FD. Primary outcomes were percentage normal versus abnormal rhythm (bradygastria, normogastria, and tachygastria). Secondary outcomes were dominant power, dominant frequency, percentage coupling, and the meal responses.

RESULTS

1751 FD patients and 555 controls from 47 studies were included. FD patients spent less time in normogastria while fasted (SMD -0.74; 95%CI -1.22 to -0.25) and postprandially (-0.86; 95%CI -1.35 to -0.37) compared with controls. FD patients also spent more fasted time in bradygastria (0.63; 95%CI 0.33-0.93) and tachygastria (0.45; 95%CI 0.12-0.78%). The power ratio (-0.17; 95%CI -0.83-0.48) and dominant frequency meal-response ratio (0.06; 95%CI -0.08-0.21) were not significantly different to controls. Correlations between EGG metrics and the presence and timing of FD symptoms were inconsistent. EGG methodologies were diverse and variably applied.

CONCLUSION

Abnormal gastric slow-wave rhythms are a consistent abnormality present in FD, as defined by EGG and, therefore, likely play a role in pathophysiology. The aberrant electrophysiology identified in FD warrants further investigation, including into underlying mechanisms, associated spatial patterns, and symptom correlations.

Effects of Rome IV Definitions of Functional Dyspepsia Subgroups in Secondary Care

BACKGROUND & AIMS

Functional dyspepsia (FD) is subdivided into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS) according to the Rome III consensus. In clinical practice, there is a major overlap between these subgroups. The Rome IV criteria included postprandially occurring symptoms in the PDS subgroup. We aimed to analyze the effects of the Rome IV criteria, compared with Rome III, on FD subgroups in patients recruited from secondary care.

METHODS

Patients with FD (n = 224; mean age, 43 ± 1 y; 77% women) were recruited from secondary-care units in Belgium and filled out symptom questionnaires, allowing subdivision according to Rome III and Rome IV criteria and identification of postprandial symptoms. Symptom patterns and demographics were compared between the subgroups. Statistical analysis was performed using the t test and the Fisher exact test.

RESULTS

According to the Rome III criteria, 25% of participants had PDS, 8% had EPS, and 67% had an overlap. Postprandial fullness, early satiation, and bloating were present in significantly more patients in the PDS and overlap groups than the EPS group (P < .0001). A higher proportion of patients in the overlap group showed symptoms such as postprandial epigastric pain and nausea than in the EPS group (both P ≤ .02). With the Rome IV criteria, the overlap group was reduced to 35%; 57% of patients were considered to have PDS and 8% to have EPS. Postprandial pain was significantly more prevalent in the PDS than in the EPS group (P ≤ .002), and postprandial nausea was significantly more prevalent in the PDS group than the overlap group (P = .007).

CONCLUSIONS

Compared with Rome III criteria, the Rome IV criteria significantly reduces the overlap between PDS and EPS groups. Studies are needed to determine if Rome IV subgroups are associated differently with psychological comorbidities and treatment responses.

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.

Progress in research of gastrointestinal motility regulation

Gastrointestinal motility is an important part of the physiological function of the digestive tract, and its dysfunction is one of the key factors that cause different gastrointestinal motility disorders. These diseases seriously affect patients' normal life. With the development of scientific research and technology, well-designed research studies have been conducted on the regulatory mechanisms of gastrointestinal motility, which mainly include the regulation of gastrointestinal hormones, intestinal microflora, neurotransmitters, brain-gut peptides, interstitial cells of Cajal, and gastrointestinal electrical activities. In addition, current studies have proved that bitter taste receptors have certain regulatory effects on gastrointestinal motility. This paper primarily discusses the relevant pathways controlling gastrointestinal motility.

Neurotensin up-regulation is associated with advanced fibrosis and hepatocellular carcinoma in patients with MAFLD

BACKGROUND & AIMS

Neurotensin (NTS), a 13-aminoacid peptide localized in central nervous system and gastrointestinal tract, is involved in lipid metabolism and promotes various cancers onset mainly by binding to neurotensin receptor 1 (NTSR1). Increased plasma levels of pro-NTS, the stable NTS precursor, have been associated with type 2 diabetes (T2D), cardiovascular diseases and metabolic associated fatty liver disease (MAFLD). We aimed to evaluate 1) the impact of NTS rs1800832 and NTSR1 rs6090453 genetic variants on liver damage in 1166 MAFLD European individuals, 2) the relation between NTS variant and circulating pro-NTS and 3) the hepatic NTS expression by RNAseq transcriptomic analysis in 125 bariatric patients.

RESULTS

The NTS rs1800832 G allele was associated with hepatic fibrosis (OR 1.27, 95% confidence interval (CI). 1.02-1.58; p = 0.03), even more in carriers of both NTS and NTSR1 G risk alleles (OR 1.17, 95% CI. 1.03-1.34; p = 0.01), with cirrhosis (OR 1.58, 95% CI. 1.07-2.34; p = 0.02) and HCC (OR 1.98, 95% CI. 1.24-3.2; p = 0.004). Pro-NTS circulating levels were correlated with T2D (p = 0.005), BMI, (p = 0.04), age (p = 0.0016), lobular inflammation (p = 0.0025), fibrosis>2 (p < 0.0001), cirrhosis (p = 0.0009) and HCC (p < 0.0001) and more so after stratification for the NTS G allele. Transcriptomic data showed that hepatic NTS expression correlated with that of fibrogenic genes (p < 0.05).

CONCLUSIONS

NTS rs1800832 variant is associated with advanced fibrosis and HCC in MAFLD patients likely affecting NTS protein activity. The rs6090453 NTSR1 gene variant synergizes with NTS rs1800832 mutation to promote liver damage. Prospective studies are necessary to confirm NTS role in liver disease progression.

The Role of GI Peptides in Functional Dyspepsia and Gastroparesis: A Systematic Review

Functional dyspepsia (FD) and gastroparesis (GP) are common disorders of the upper gastrointestinal tract. The pathophysiology of these conditions is likely to be heterogenous, and factors such as altered motility, sensitivity and response to nutrition have been identified as putative underlying mechanisms. Motility, sensitivity as well as responses to nutrition can be influenced or mediated by peptide hormones and serotonin released from the gastrointestinal mucosa. This review summarizes the role of GI peptides in functional dyspepsia and gastroparesis. In most studies, the levels of somatostatin, ghrelin, and motilin did not differ between healthy volunteers and FD or GP patients, but higher symptom burden was often correlated with higher peptide levels. Ghrelin and motilin receptor agonists showed promising results in improvement of the gastric emptying, but the link with improvement of symptoms is less predictable. Serotonin agonists have a potential to improve symptoms in both FD and idiopathic gastroparesis. Drugs acting on the GLP-1 and on the PYY receptors deserve further investigation. There is a need for systematic large scale studies.

Noninvasive biomarkers of gut barrier function identify two subtypes of patients suffering from diarrhoea predominant-IBS: a case-control study

Background

Alterations of the small-intestinal permeability (s-IP) might play an essential role in both diarrhoea-predominant IBS (D-IBS) and celiac disease (CD) patients. Our aims were to analyse in D-IBS patients the symptom profile along with the levels of urinary sucrose (Su), lactulose (La), mannitol (Ma), and circulating biomarkers (zonulin, intestinal fatty acid binding protein - I-FABP, and diamine oxidase - DAO) of the gastrointestinal (GI) barrier function. The pro-inflammatory interleukins 6 and 8 (IL-6 and IL-8), the plasma values of lipopolysaccharide (LPS), and Toll-like receptor 4 (TLR-4) were also investigated. Besides, these biomarkers were compared with those in CD and healthy controls (HC). Finally, comparisons were performed between D-IBS patients with [D-IBS(+)] and without [D-IBS(−)] increased s-IP according to normal or altered La/Ma ratio.

Methods

The study included 39 D-IBS patients, 32 CD patients, and 20 HC. GI permeability was assayed by high-performance liquid chromatography determination in the urine of Su and La/Ma ratio. ELISA kits assayed circulating concentrations of zonulin, I-FABP, DAO, IL-6, IL-8, LPS, and TLR-4. The Mann–Whitney or the Kruskal–Wallis with Dunn’s post-test was used to assess differences among the groups.

Results

As for the La/Ma ratio, %Su, and I-FABP levels, D-IBS patients were significantly different from CD, but not HC. IL-6 levels were significantly higher in CD than HC, whereas IL-8 levels were significantly higher in both D-IBS and CD patients than HC. By opposite, LPS, and TLR-4 concentrations did not differ significantly among the groups. When D-IBS patients were categorised according to normal or altered s-IP, D-IBS(+) patients had %La, %Su, I-FABP, and DAO levels significantly higher than D-IBS(−) ones. The inflammatory parameters and markers of bacterial translocation (namely, IL-6 and LPS) were significantly higher in D-IBS(+) patients than D-IBS(−) ones.

Conclusions

The present study suggests that two distinct D-IBS subtypes could be identified. The investigation of possible s-IP alterations (i.e., considering the La/Ma ratio) might be useful to assess better and categorise this heterogeneous D-IBS population.

Trial registration

NCT01574209. Registered March 2012. First recruitment started in April 2012.

Gastroduodenal motility disorders

PURPOSE OF REVIEW

This review summarizes recent progress in the epidemiology, pathophysiology and treatment of gastroduodenal motility disorders with an emphasis on functional dyspepsia and gastroparesis.

RECENT FINDINGS

Pathophysiological research has focused on the association of delayed emptying and impaired accommodation with symptom pattern. Studies also confirmed the presence of altered mucosal integrity and low-grade immune activation in the duodenum in functional dyspepsia, while changes in numbers of interstitial cells of Cajal and myenteric neurons were confirmed in gastroparesis. Treatment advances in gastroparesis include new prokinetics such as the ghrelin receptor agonist relamorelin and the antiemetic agent aprepitant. The efficacy and use of neuromodulators were reviewed and new management guidelines for functional dyspepsia were published.

SUMMARY

Pathophysiological research has focused on cellular changes in gastroparesis and gastroduodenal motility disorders. New treatments include relamorelin and aprepitant for gastroparesis.

Electroacupuncture for patients with refractory functional dyspepsia: A randomized controlled trial

BACKGROUND

To test the efficacy of electroacupuncture for patients with refractory functional dyspepsia (FD).

METHODS

A 24-week, 2-arm, single-blind, randomized controlled trial was conducted at three hospitals in China. Patients with refractory FD were randomly assigned to receive 20 sessions of authentic or sham electroacupuncture in a treatment duration of 4 weeks. The primary outcome was complete absence of dyspeptic symptoms at 16 weeks after initiation of acupuncture (week 16). The secondary outcomes included adequate relief of dyspeptic symptoms, Leeds Dyspepsia Questionnaire (LDQ), Nepean Dyspepsia Index (NDI), and adverse events. Intention-to-treat analysis was performed.

KEY RESULTS

Two hundred patients were included, of which 196 (98%) completed follow-up data at week 24. At week 16, 17 (17%) patients in the authentic electroacupuncture group vs 6 (6%) patients in the sham group achieved the primary outcome (P = .014). Sixty-two (62%) patients had adequate relief in the authentic electroacupuncture group, as compared to 22 (22%) in the sham group (P = .001). The scores of LDQ and NDI were significantly improved in both groups at week 16, and patients in the authentic electroacupuncture group have more improvements (LDQ, mean difference, -2.2, 95% confidence interval, -2.3 to -2.1, P < .001; NDI, -7.3, -10.5 to -4.2, P < .001). Results were similar for all the outcomes assessed at week 24. No serious adverse events were reported in both groups.

CONCLUSION

Acupuncture efficaciously improves dyspeptic symptoms in patients with refractory FD.

Colonic Transit Time and Gut Peptides in Adult Patients with Slow and Normal Colonic Transit Constipation

PURPOSE

To investigate whether pathophysiological differences exist among healthy controls (HC) and patients with slow and normal transit constipation (STC and NTC), we evaluated (1) gastrointestinal (GI) symptoms using validated questionnaires; (2) circulating concentrations of neurotensin, motilin, corticotrophin-releasing factor (CRF), and somatostatin; and (3) possible differences in frequency distribution of the neurotensin rs1800832 A/G and Neurotensin Receptor 1 rs6090453 C/G SNPs.

METHODS

Fifty-one patients with severe functional constipation and 20 HC completed the study. Symptoms were evaluated by GSRS and Constipaq scoring system. Plasma concentrations of GI peptides were evaluated by ELISA on fasting and six sequential blood samples after a standard meal. Genotyping was performed by PCR and endonuclease digestion.

RESULTS

Symptom profiles largely overlapped between NTC and STC patients. As for peptide profiles, neurotensin showed lower concentrations at 60 and 90 min in STC versus HC, and motilin showed throughout the curve 85% and 82% lower levels in STC than HC and NTC, respectively. Finally, neurotensin polymorphism resulted in being associated with the peptide levels.

CONCLUSIONS

Symptom profile is not a reliable tool to discriminate STC, whilst the GI peptide profiles might help in identifying it.