Introduction

Functional dyspepsia (FD) is a common gastrointestinal disorder, affecting 10–20% of the population. Although Helicobacter pylori (Hp) eradication is recommended in FD, its therapeutic benefit is modest, and no clear correlation exists between eradication success and symptom improvement. Emerging evidence suggests that microbiota changes may contribute to symptom relief beyond Hp clearance. Since antibiotics and acid-suppressing agents—both integral to eradication regimens—can significantly affect the gut microbiota, it is uncertain whether the observed clinical improvement stems primarily from the elimination of H. pylori, or from microbiota shifts induced by the treatment itself.

Aims & Methods

We aimed to investigate the effects of antibiotics and a potassium-competitive acid blocker on microbiome changes in FD patients with or without Hp infection, and to examine their association with symptom improvement. Four Hp(+) and eight Hp(-) patients with FD, diagnosed based on the Rome IV criteria, were prospectively enrolled. All patients were treated with tegoprazan 50 mg, amoxicillin 1000 mg, and clarithromycin 500 mg, twice daily for 10 days, regardless of Hp status. Hp infection was determined using a rapid urease test and a serum Hp IgG test. Symptom changes were assessed using the Korean version of the Nepean Dyspepsia Index (NDI-K) at baseline, 3 months, and 6 months after eradication. Biopsy samples were taken from the antrum, duodenal bulb, and second portion of the duodenum at baseline and 3 months after eradication. Microbiome profiling via 16S rRNA sequencing was performed to assess alpha and beta diversity, and LEfSe was used to identify discriminative bacterial taxa. Eosinophil counts were also measured at baseline and 3 months after eradication.

Results

At baseline, the median NDI-K total score was 71.5 in the Hp(+) group and 33.5 in the Hp(-) group. Three months after eradication therapy, the median scores decreased to 26.5 and 12.0, respectively. This reduction in symptom scores persisted through six months, with median NDI-K total scores of 21.0 and 11.0, respectively. In the Hp(+) group, the ACE and Chao1 alpha indices in the duodenal bulb were significantly decreased at 3 months after eradication compared with baseline. All indices of alpha diversity in the antrum and duodenal second portion were decreased at 3 months after eradication compared with baseline, although the changes were not statistically significant. In the Hp(-) group, alpha diversity in the antrum and duodenum tended to decrease at 3 months after eradication compared with baseline. At the phylum level, Proteobacteria were predominant in both groups, followed by Firmicutes, Bacteroidetes, and Actinobacteria. In the antrum of the Hp(-) group, Proteobacteria decreased in relative abundance from 59.9% at V2 to 48.7% at V4. In contrast, Firmicutes showed a tendency to increase from 17.7% at V2 to 26% at V4. LEfSe analysis identified multiple species-level differences in microbial composition between the two groups. Median eosinophil counts decreased in the duodenal bulb and the second portion of the duodenum at 3 months after eradication, regardless of Hp status.

Conclusion

Hp eradication therapy resulted in gut microbiota alterations and symptom improvement, regardless of H. pylori status. Duodenal microbial diversity tended to decrease after treatment, and this pattern was observed in both Hp(+) and Hp(–) groups, although the magnitude of change differed. These microbiota shifts may have contributed to the observed improvement in symptoms.

References

1. Ford, Alexander C., et al. "Functional dyspepsia." The Lancet 396.10263 (2020): 1689-1702.
2. Kim, Sung Eun, et al. "Prevalence and risk factors of functional dyspepsia in health check-up population: a nationwide multicenter prospective study." Journal of neurogastroenterology and motility 24.4 (2018): 603.
3. Tan, Victoria PY, et al. "Randomised clinical trial: rifaximin versus placebo for the treatment of functional dyspepsia." Alimentary pharmacology & therapeutics 45.6 (2017): 767-776.
4. Imhann, Floris, et al. "Proton pump inhibitors affect the gut microbiome." Gut 65.5 (2016): 740-748.
5. Oh, Jung Hwan, et al. "Clinical practice guidelines for functional dyspepsia in Korea." Journal of neurogastroenterology and motility 26.1 (2020): 29.

Disclosure

This study was supported by research funding from HK inno.N.

Introduction

Eosinophilic Esophagitis (EoE) is a clinicopathological disease that requires an integrated assessment combining clinical, endoscopic, and histological findings. Despite this, treatment decisions often remain symptom based. A treat-to-target strategy has recently been proposed to guide EoE management.

Aims & Methods

Retrospective single-center study of EoE patients followed between March 2012 and January 2024, with ≥12 months of follow-up. Clinical, endoscopic, histological data, and complications were assessed using the I-SEE score.

Results

A total of 82 patients with EoE were evaluated [75.6% (n=62) male, mean age 29 ± 13 years], with 37.8% (n=31) diagnosed during childhood. The most frequent symptom was food impaction (74.4%), and atypical symptoms were more common in pediatric patients (p=0.014). At baseline, 55.1% (n=43) presented with a fibrostenotic phenotype, more frequently in adults (p=0.012), and 32.9% (n=27) had moderate-to-severe disease based on the I-SEE score.
During follow-up, 56.1% (n=46) developed complications, most commonly food impaction requiring endoscopy. The presence of a fibrostenotic phenotype on initial endoscopy was a predictor of complications (OR 3.122; 95% CI 1.210–8.055; p=0.019). Both fibrostenotic phenotype (p=0.018) and moderate-to-severe I-SEE scores (p=0.004) were associated with increased need for therapeutic switching.
At 12 months, 50.0% (n=41) were asymptomatic; however, only 12.2% (n=10) had endoscopic healing and 9.8% (n=8) histologic remission. Throughout the study period, the rates of endoscopic and histologic healing remained below 25%.

Conclusion

The authors highlight the clinical dissociation of inflammatory activity and emphasize the importance of endoscopic and histologic healing to prevent disease progression.

References

Dellon, Evan S., et al. "A clinical severity index for eosinophilic esophagitis: development, consensus, and future directions." Journal of Allergy and Clinical Immunology 150.1 (2022): 33-47.

Introduction

Gastric visceral hypersensitivity (VH) is a key pathophysiological feature of functional dyspepsia (FD), characterized by enhanced perception of gastric distension and postprandial pain. Recent studies suggest that dietary gluten may act as a pro-nociceptive factor in FD, particularly in individuals without celiac disease but with dyspeptic symptoms. However, mechanisms linking gluten to VH remain elusive.

Aims & Methods

In the clinical arm, multiple linear regression assessed associations between gluten intake and symptom frequency/severity (postprandial fullness, epigastric pain, early satiety), adjusting for age, sex, and BMI. In the experimental arm, Sprague-Dawley rats received either a 20% gluten diet or gluten-free diet for 8 weeks; an iodoacetamide-induced FD model served as a positive control. Gastric sensitivity was evaluated by abdominal withdrawal reflex (AWR) and electromyography (EMG) following surgical placement of a gastric balloon and electrodes. Duodenal and fecal samples were collected for 16S rRNA microbiota profiling and RNA-seq. Histological and molecular analyses included H&E staining, intraepithelial lymphocyte (IEL) counts, RT-qPCR of cytokines, and quantification of GFAP, Substance P, and MAPK components by RT-qPCR, Western blot, or immunofluorescence. Aprepitant (10 mg/kg/day) was administered during the final 2 weeks to assess its therapeutic effect.

Results

A total of 74 patients diagnosed with FD based on Rome IV criteria (EPS (epigastric pain syndrome)+PDS (postprandial distress syndrome): 29, EPS: 12, PDS: 33) and 29 healthy controls were included. FD patients, particularly EPS subtypes, exhibited significantly higher gluten intake than healthy controls (P＜0.001). Multiple linear regression revealed that gluten intake was a significant positive predictor of symptom frequency and severity in FD patients (frequency: β = 0.0407, 95% CI: 0.0197–0.0617, P ＜0.001; severity: β = 0.0230, 95% CI: 0.0091–0.0368, P＜0.01).
In rats, gastric sensitivity in the 20% gluten group was comparable to the iodoacetamide-induced FD model and significantly greater than the gluten-free control group, exhibited by slower weight gain, increased AWR score, higher area under the curve (AUC) of electromyograph and reduced 24-hour food intake. Compared to controls, gluten-fed rats showed reduced fecal abundance of Lactobacillus and Lactococcus, increased Lachnoclostridium, and decreased Lactococcus in duodenal mucosa. Duodenal tissues also exhibited elevated intraepithelial lymphocyte (IEL) counts, increased expression of IL-1β, IL-4, and IL-5, and upregulation of inflammation-related genes Reg1α and Reg3β, indicating low-grade mucosal inflammation. In addition, gluten exposure significantly increased duodenal expression of Substance P (SP), GFAP, and phosphorylated MAPK pathway proteins.
At week 8, rats in the gluten group were treated with either the NK1R antagonist aprepitant or saline. Aprepitant administration significantly attenuated VH, as shown by reduced AWR scores and EMG AUC compared with the gluten+saline group. Aprepitant also suppressed the expression of IL-1β, IL-4, Reg1α, Reg3β, and MAPK-related genes, suggesting a key role of SP-mediated neuroimmune activation in gluten-induced VH.

Conclusion

Long-term high gluten intake induces gastric hypersensitivity, accompanied by gut dysbiosis, mucosal inflammation, and SP-mediated MAPK signaling. Targeting neuroimmune pathways may offer novel therapeutic strategies for gluten-induced epigastric symptom management.

References

POMENTI S, DEVINSKY J, JODORKOVSKY D. Diet for Functional Gastrointestinal Disorders/Disorders of Gut-Brain Interaction [J]. The Medical clinics of North America, 2022, 106(5): 899-912.
SHAH A, KANG S, TALLEY N J, et al. The duodenal mucosa associated microbiome, visceral sensory function, immune activation and psychological comorbidities in functional gastrointestinal disorders with and without self-reported non-celiac wheat sensitivity [J]. Gut microbes, 2022, 14(1): 2132078.

Introduction

Biomarkers, like stool short-chain fatty acids (SCFA), metabolites by fermented nondigestible carbohydrates and branched-chain fatty acids (BCFA) derived from the metabolism of essential amino acids may allow for objective measurements of IBS biological changes without self-reporting bias. Diets low in FODMAP significantly reduce the abnormal fecal total SCFA in IBS patients, indicating that the diet normalizes the IBS patients’ abnormal fecal SCFA output.

Aims & Methods

By conducting an exploratory analysis, we aimed to measure stool SCFAs/BCFAs level changes in a subgroup of subjects enrolled in an RCT evaluating the efficacy of a Mediterranean version of the Low-FODMAPS diet (MED-LFD) compared to the nutritional recommendations of the British National Institute for Health and Care Excellence (NICE) for managing non-constipation IBS. A subset of 40 (23 MED-LFD & 17 NICE) patients provided stool samples at 3 time points: Before dietary intervention, at the 1st (4 weeks after initiation of intervention for NICE and at the end of phase 2 for MED-LFD), and the 2nd folow-up (FU), 6 months after intervention initiation. We measured symptoms severity using IBS-SSS. Table 1 shows the detailed measurement of the consumed FODMAPs per day assessed using a triple-pass 24-hour dietary recall twice at the two FUs.

Table 1.

	1st Follow-up			2nd Follow-up
FODMAPs, M(IQR)	MED-LFD (N=20)	NICE (N=17)	p	MED-LFD (N=19)	NICE (N=15)	p
Excess fructose, g/meal	0.17 (0.13-0.38)	0.19 (0.11-0.83)	0.563	0.22 (0.11, 0.39)	0.3 (0.2, 0.47)	0.275
Sorbitol, g/meal	0.02 (0.0-0.06)	0.11 (0.01-0.39)	0.021	0.02 (0, 0.08)	0.14 (0.01, 0.28)	0.245
Mannitol, g/meal	0.004 (0.0-0.07)	0.06 (0.01-0.13)	0.077	0.02 (0.01, 0.13)	0.04 (0, 0.09)	0.664
Fructans, g/meal	0.43 (0.33-0.54)	0.63 (0.48-0.7)	0.051	0.54 (0.27, 0.8)	0.73 (0.51, 1.07)	0.080
GOS, g/meal	0.09 (0.07-0.18)	0.21 (0.09-0.36)	0.106	0.14 (0.07, 0.32)	0.23 (0.14, 0.48)	0.171
Total oligosaccharides, g/meal	0.54 (0.39-0.79)	0.85 (0.65-1.1)	0.038	0.7 (0.33, 1.16)	1.08 (0.72, 1.52)	0.050
Total FODMAPs, g/meal	1.36 (1.0- 1.90)	2.51 (1.68-3.42)	0.011	1.54 (1.10-2.62)	2.62 (1.42-3.90)	0.086
Lactose, g/meal	0.04 (0.01-0.56)	1.36 (0.47-2.46)	0.002	0.32 (0.04, 1.15)	0.27 (0.01, 2.39)	0.808

SCFAs/BCFAs were extracted from frozen samples and analyzed using Gas Chromatography/Mass Spectrometry. SCFAs and BCFAs levels were measured in umol/g of stool. A paired/unpaired t-test was performed to illustrate the organic acid changes among and within two groups. In multiple groups comparison, significant differences between means were examined using one-way analysis of variance. A polynomial regression model was used to describe the relation between BCFAs/SCFAs levels change with IBS-SSS change from baseline at the 1st FU.

Results

We detected a significant reduction in the concentrations of total SCFAs and BCFAs in the MED-LFD (-21.4±20 and -0.429±0.882) and the NICE (-9.9±17.7 and -0.819±0.933) groups, respectively, at the 1st FU. At the 2nd FU, similar reductions from the baseline concentration levels were detected in both intervention groups (total SCFAs: -20.2±18.7 in MED-LFD vs. -10.9±7.4 in NICE; total BCFAs: -0.494±0.806 in MED-LFD vs. -0.76±0.83 in NICE). A polynomial association was observed between the changes in IBS-SSS scores and the changes in stool concentrations of BCFAs and SCFAs from baseline to the 1st FU. Specifically, there was a slight upward trend in the difference of BCFA levels, indicating that a decrease in IBS-SSS scores is associated with a reduction in BCFA levels during the 1st follow-up. This trend peaked around an IBS-SSS change of minus 50 points, the cut-off value for clinical response. Beyond this point, this association slightly declines. A similar trend was noted for SCFA level changes, with the peak occurring around an IBS-SSS change of minus 100 points, after which the association diminishes.

Conclusion

SCFA/BCFA stool levels changes from baseline might be an objective measure of successful dietary intervention for IBS

References

1. Ju X, Jiang Z, Ma J, Yang D. Changes in Fecal Short-Chain Fatty Acids in IBS Patients and Effects of Different Interventions: A Systematic Review and Meta-Analysis. Nutrients. 2024;16(11):1727
2. Rossi M, Aggio R, Staudacher HM, et al. Volatile Organic Compounds in Feces Associate With Response to Dietary Intervention in Patients With Irritable Bowel Syndrome. Clin Gastroenterol Hepatol. 2018;16(3):385-391.e1.

Introduction

Emerging epidemiologic evidence suggested that moderate-to-vigorous physical activity (MVPA) was associated with a lower risk of steatotic liver disease (SLD).¹ However, several issues remain unanswered. First, prospective association between PA and hepatic steatosis was less investigated, with few studies mainly in Western populations,^{2, 3} but not in Chinese populations. Second, since sedentary behavior and PA are interrelated and may jointly affect the health outcomes,⁴ a key concern is whether moderate-to-vigorous physical activity (MVPA) can mitigate the detrimental link between sedentary time and SLD. Moreover, PA was shown to affect the gut microbiome by altering the bile acid profile and promoting the production of metabolites such as short-chain fatty acids^5,6 with benefit to SLD in animal models.⁷ However, PA-related gut microbes and metabolites, as well as their associations with SLD risk were rarely investigated at the population level.

Aims & Methods

We investigated the association between PA and the SLD risk in a cohort of 2,942 adults from the Anhui Liver Disease Study (ALDS), in which PA and SLD were measured using a validated self-reported questionnaire and transient elastography, respectively. In a subset of ALDS (n=330), we further identified gut microbial changes and serum metabolites related to MVPA assessed by accelerometer, and examined their associations with SLD risk. Fecal samples for 16S ribosomal RNA sequencing were collected twice (1-year apart) to evaluate 1-year microbial changes, targeted metabolomics analysis of baseline serum samples was performed using liquid chromatography tandem mass spectrometry, while PA was measured using a wrist-worn accelerometer for 3 consecutive days at baseline. Cox and Logistic regression models were used to calculate hazard ratios (HRs) and odds ratios (ORs) with 95%CIs, respectively.

Results

From 2020 to 2025, 565 SLD cases were newly diagnosed. MVPA levels were inversely (per 1-SD increase HR=0.91, 95%CI: 0.83–0.99) and sedentary hours were positively associated with the risk of SLD (HR=1.13, 95%CI: 1.03–1.24). Relative to long-low group (i.e., participants with long sedentary time and low MVPA level), HRs (95%CIs) for SLD risk were 1.00 (0.78–1.28), 0.93 (0.73–1.19), and 0.75 (0.58–0.97) for long-high, short-low, and short-high group, respectively. The α-diversity decreased in the low MVPA group (p=0.024) and the β-diversity changed in both low and high MVPA groups (all p=0.001). We identified 14 microbial genera whose relative abundance significantly changed in low or high MVPA group (all p_FDR<0.05). Among these genera, Proteus and Synergistes were associated with both low and high MVPA but in opposite directions, and were associated with SLD with ORs (95%CIs) of 1.15 (1.01–1.32) and 0.91 (0.78–1.06), respectively. Targeted metabolomics showed an inverse association between MVPA and serum L-Valine (β=-0.068, p_FDR=0.031), which was positively related to SLD risk (OR=16.40, 95%CI: 2.67–111.94). Significant correlations were also found between PA-associated microbial genera and L-Valine.

Conclusion

MVPA may modify gut microbial diversity and composition, as well as serum metabolite levels, and is associated with lower SLD risk, whereas sedentary behavior is associated with higher SLD risk.

References

[1] European Association for the Study of the Liver . Electronic address eee, European Association for the Study of D, European Association for the Study of O, et al. EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD). J Hepatol 2024;81:492-542.
[2] McDonough DJ, Mathew M, Pope ZC, et al. Aerobic and Muscle-Strengthening Physical Activity, Television Viewing, and Nonalcoholic Fatty Liver Disease: The CARDIA Study. Journal of Clinical Medicine 2023;12.
[3] Liu M, Ye Z, Zhang Y, et al. Accelerometer-derived moderate-to-vigorous physical activity and incident nonalcoholic fatty liver disease. BMC Medicine 2024;22.
[4] Ekelund U, Tarp J, Steene-Johannessen J, et al. Dose-response associations between accelerometry measured physical activity and sedentary time and all cause mortality: systematic review and harmonised meta-analysis. Bmj 2019;366:l4570.
[5] Penney N, Barton W, Posma JM, et al. Investigating the Role of Diet and Exercise in Gut Microbe-Host Cometabolism. mSystems 2020;5.
[6] Campaniello D, Corbo MR, Sinigaglia M, et al. How Diet and Physical Activity Modulate Gut Microbiota: Evidence, and Perspectives. Nutrients 2022;14.
[7] Chen J, Vitetta L. Gut Microbiota Metabolites in NAFLD Pathogenesis and Therapeutic Implications. Int J Mol Sci 2020;21.

Introduction

The lactulose breath test (L-BT) is a non-invasive method to assess small intestinal bacterial overgrowth (SIBO). However, diagnostic criteria for intestinal methanogenic overgrowth (IMO) differ among experts, and international guidelines lack a definition. Methanogenic flora is linked to slower gut transit in irritable bowel syndrome (IBS), but the effects of methane-targeting treatments on methanogens, colonic transit, and stool form remain unclear.

Aims & Methods

To examine relationships between methanogenesis, constipation, pain and bloating in healthy volunteers and patients with and without IBS. METHODS: Cross-sectional study on adults with L-BT between 2016–2024 at a single center. Each patient completed a Rome IV questionnaire, sociodemographic and medical data and Bristol stool scale. IMO was diagnosed if there were more than 3 measurements of CH₄ over 10 ppm over 180 minutes. We examineded 3 alternate diagnostic thresholds: (A) 10 ppm at any time (American criteria or C1); (B) 10 ppm over baseline before 90 minutes (C2); and (C) 10 ppm over baseline before 60 minutes (C3), We considered “high producers” of CH₄ those that had 2 measurements over 60 ppm. Statistical analysis with Mann-Whitney and Kruskal Wallis test.

Results

We included 5,053 subjects who underwent L-BT (mean age 49 years, 81% women). Of these, 10% were exclusive H2 producers, 2% CH4 producers, and 2.7% were non H2/CH4 producers. CH4 producers had a higher frequency of constipation (p<0.001) and greater total CH4 production in the Bristol 1-2 group. CH4 production over 180 minutes was lower in IBS-D patients, though the overall methane production rate was similar to healthy volunteers. Based on diagnostic thresholds, 92.6% of constipated patients met C1, 52.3% C2, and 18.1% C3, with significant differences (p=0.001). Stricter IMO criteria were associated with greater bloating and pain intensity.

Conclusion

The high proportion of methane production in our asymptomatic controls, compared to previous series, may reflect demographic differences. Methane producers had a higher frequency of constipation. The IMO diagnosis rate varied depending on the criteria used, with stricter criteria identifying patients with more frequent constipation, bloating, and abdominal pain.

Disclosure

None

Introduction

Irritable bowel syndrome (IBS) pathophysiology is multifactorial, with fermentable, oligo, di- and mono-saccharides and polyols (FODMAP) playing a role in symptom induction, presumably through osmotic effects and rapid colonic fermentation. While dietary studies assessed effects on symptoms, few have investigated the direct impact on colonic motility.

Aims & Methods

Using high-resolution colonic manometry (HRCM), we examined the effects of intracolonic fructose, fructans (fructo-oligosaccharides), or mannitol infusion on colonic motility in healthy volunteers (HV).
A double-blind three-way crossover study was conducted in 15 HVs, with a ≥ 2-week wash-out period between visits. After three days of a low FODMAP and low fiber diet, subjects came fasted to the hospital's endoscopy unit. They received a 250 mL water enema before advancing a 36-sensor solid state HRCM catheter with perfusion lumen into the ascending colon via colonoscopy under conscious sedation. After a 1 h recovery period, colonic pressures were recorded 1 h in the fasted state, for 20 min during infusion of FODMAP in the ascending colon (200 mL 290 mOsm/kg fructose, fructans, or mannitol), 2 h post-infusion, and 1 h postprandially after a standardized low-calorie meal. Colonic motor patterns were manually identified and compared between the three FODMAPs, with long ones ≥12 cm and high amplitude ones with at least 3 sensors ≥100 mmHg. Gastrointestinal symptoms were recorded every 15 minutes during the 4.5 h measurement. Results are presented as median with minimum and maximum ranges.

Results

Fifteen HV, 40% male (mean age 32 years (range 19-64 y), mean BMI 22.6 kg/m² (range 19.6-33.1)), completed the three study visits. Post FODMAP infusion, a significant difference in long anterograde patterns (p=0.04) was detected (Table). Postprandially, long synchronous (p=0.001) and long anterograde (LA) (p=0.0008) were more frequently observed with fructans, while mannitol tended to induce long retrograde patterns (p=0.07). Many of the long anterograde patterns were pan-colonic interrupted pressurizations (IP; previously described as related to gas transit; Leibbrandt J Clin Med 2023), and these were significantly more frequent after fructans infusion (p=0.004). High-amplitude retrograde-propagating contractions occurred 36 times in five HV: 50% after mannitol, 25% after fructans, and 25% after fructose infusion. There was no significant difference in gastrointestinal symptoms between the three FODMAPs, although flatulence and abdominal cramps were slightly increased after infusion of fructans.

Type of colonic motor pattern	Fructans	Fructose	Mannitol	P-value	Adjusted p-value
Post FODMAP_LA	23 (5-46)	13 (4-38)	17 (1-50)	0.04
Postprandial_LS	6 (0-22)*	2 (0-25)	2 (0-10)*	0.001	*0.003
Postprandial_LA	40 (6-60)*°	20 (3-58)°	17 (3-37)*	0.0008	*0.001/°0.02
Postprandial_IP	12 (0-55)*°	6 (0-39)°	5 (0-18)*	0.004	*0.008/°0.04

Conclusion

Fructans and mannitol alter colonic motility patterns in distinct ways. Upon fructan infusion, there is a higher frequency of anterograde and synchronous activity, including interrupted pressurizations, which are suggested to be linked to gas transit. However, the frequency of these motor patterns was not altered by mannitol. These responses to different FODMAPs may contribute to symptom generation in IBS.

References

Van den Houte et al. Gastroenterology 2024
Leibbrandt J et al. Clin Med 2023