Introduction

Response rates to the Low FODMAP Diet (LFD) in IBS vary and predictors of benefit remain poorly defined. While several studies from Western populations have identified microbial signatures linked to response, data from Asian cohorts remain limited.

Aims & Methods

This study aims to identify microbial predictors and longitudinal microbiome shifts in Asian IBS-D patients consuming a LFD. We recruited 20 adult Asian patients with IBS-D diagnosed according to the ROME-IV criteria. All subjects received LFD dietary advice from a dietitian at initiation and were followed-up for a total of 28-days. Clinical response was assessed by a ≥50-point improvement in the IBS Symptom Severity Score (IBS-SSS) from Day 0 (baseline) as compared to follow-up at Day 28. Stool samples were collected at baseline, Day 14, and Day 28. Microbial DNA was extracted using bead-beating and Qiagen PowerFecal kits, and the V3–V4 region of the 16S rRNA gene was amplified and sequenced on the Illumina MiSeq platform. Bioinformatic processing included denoising with DADA2, taxonomic assignment using the SILVA 138 database, and rarefaction to even sequencing depth. Microbiome metrics included alpha diversity (Shannon and Simpson), beta diversity (Bray-Curtis PCoA with PERMANOVA), and differential abundance testing with DESeq2.

Results

By Day 28, 11 of 20 patients (55%) achieved clinical response, with a median IBS-SSS reduction of 172 points (IQR: 88–248), compared to 24 points in non-responders (IQR: −11 to 55; p=0.003). Alpha diversity was not significantly different between groups, but responders exhibited a trend toward higher Shannon and Simpson diversity at baseline. Beta diversity analysis using Bray-Curtis dissimilarity revealed partial clustering by responder status (PERMANOVA p=0.06), and PCoA plots showed individual-specific shifts in community structure across time, indicating that the LFD induces personalized microbiome trajectories.
At baseline, responders had significantly higher relative abundances of butyrate-producing and anti-inflammatory genera, including Ruminococcus, Blautia, Eubacterium siraeum, and Bifidobacterium bifidum (adjusted p<0.05). These findings are consistent with prior reports, including Bennet et al. (2018) and Vervier et al. (2022), where such taxa were part of a “health-like” IBS-P (pathogen-enriched) to IBS-H (health-like) axis. The enrichment of Blautia and Ruminococcus is particularly noteworthy as these are established butyrate producers involved in maintaining colonic barrier function and reducing visceral hypersensitivity. By Day 28, differential abundance analysis revealed that responders exhibited increases in Ruminococcus bicirculans, Parabacteroides gordonii, and Weissella cibaria. In contrast, non-responders showed persistence or increases in taxa such as Tyzzerella and Olsenella, which have been associated with inflammation or IBS severity in prior studies (Chuah et al., 2024).

Conclusion

This study provides novel microbiome insights from an underrepresented Asian IBS population consuming a LFD. Despite dietary and baseline microbiota differences from Western populations, we observed remarkably consistent microbiome predictors of response, including higher baseline levels of butyrate-producing taxa and favorable microbial restructuring during the intervention. These results reinforce the reproducibility and functional relevance of microbiome predictors in IBS dietary therapy, and support microbiome profiling as a potential tool for personalized dietary guidance across a diverse global population.

References

Bennet SMP et al. Multivariate modelling of faecal bacterial profiles of patients with IBS predicts responsiveness to a diet low in FODMAPs. Gut. 2018 May;67(5):872-881.
Vervier K et al. Two microbiota subtypes identified in irritable bowel syndrome with distinct responses to the low FODMAP diet. Gut. 2022 Sep;71(9):1821-1830.
Chuah KH, Mahadeva S. Can we predict who will respond to a low-FODMAP diet in irritable bowel syndrome? J Gastroenterol Hepatol. 2024 Feb;39(2):217-218. ​

Introduction

COVID-19 infection may increase the risk of developing Disorders of Gut-Brain Interaction (DGBI). However, the extent of this effect on a population level is poorly understood. We performed a two-country survey to address this issue.

Aims & Methods

A population-based Internet survey with pre-defined demographic quotas was conducted across the UK and USA in 2017 (pre-pandemic, n=4050) and repeated in 2023 (post-pandemic, n=4002). The surveys included the Rome IV diagnostic questionnaire, and questions about non-gastrointestinal somatic symptoms, anxiety and depression, quality of life, and healthcare utilization. The 2023 survey also included questions regarding COVID-19 infection and illness history.

Results

The overall DGBI prevalence, i.e., meeting diagnostic criteria for at least one DGBI, has significantly increased from the pre- to post- pandemic era (38.3% vs. 42.6%, OR 1.20, 95% C.I 1.09-1.31), with similar findings independently noted in the UK and USA. The rise in DGBI was observed within the oesophageal (8.8% vs. 10.1%, OR 1.16), gastroduodenal (11.9% vs. 16.4%, OR 1.45), and bowel domains (30.1% vs. 32.5%, OR 1.12). The two most widely investigated DGBI showed large post-pandemic prevalence increases, with functional dyspepsia rising from 8.3% to 11.9% (OR 1.48) and irritable bowel syndrome from 4.7% to 6.0% (OR 1.31).
In multivariable analysis, factors significantly associated with having DGBI in the post-pandemic era included younger age, female sex, anxiety, depression, medium-to-high somatic symptom severity, increasing number of COVID-19 infections, experiencing abdominal pain or diarrhoea during COVID-19 infection, and suffering with long-COVID.
Individuals with DGBI in the post-pandemic era, in particular those with long-COVID, reported reduced quality of life and higher mood disturbances, somatic symptom reporting and healthcare use than individuals with DGBI in the pre-pandemic era.

Conclusion

The population prevalence and burden of DGBI have increased following the COVID-19 pandemic. Healthcare services and research funding bodies need to adapt to this post-COVID surge in DGBI and address how to best manage this patient group.

Clinical Case Summary

A 74-year-old male presented in November 2022 with abdominal distension, mild anemia, recurrent oral aphthae, and alternating diarrhea and constipation. A 2021 colonoscopy was normal. Enterotomography revealed two segments of irregular parietal thickening in the distal ileum. Repeated colonoscopy confirmed thickened distal ileum with ulcerations. Biopsies identified chronic active ileitis without granuloma; stains for fungi and acid-fast bacillus were negative.
A presumptive diagnosis of Crohn’s disease was made, and azathioprine and prednisone were initiated. In March 2023, the patient developed ileal perforation requiring urgent right ileocolectomy with ileostomy. On follow-up endoscopies, gastric ulcer with unremarkable histopathology and perianastomotic Rutgeerts i2 recurrence were identified, and infliximab was initiated.
In January 2024, patient complained of intense cervical odynophagia and new genital and oral ulcers. Endoscopy showed an ulcer on the aryepiglottic fold, while biopsy of the genital lesion revealed erosive chronic inflammation with fibrinoleukocytic exudate and positive C3c immunofluorescence.
In March 2024, methotrexate and colchicine were initiated for suspected Behçet’s disease, with incomplete improvement of oral ulcers, and a trial of thalidomide 100mg qd was performed with adequate clinical control. A December 2024 endoscopy was normal, and colonoscopy showed only minimal erosions in the blind loop. Patient remained clinically well, with clinical remission.
This case highlights an uncommon presentation of Behçet’s disease (BD). While gastrointestinal involvement is well-documented in BD, the onset in advanced age, as well as initial diagnosis as Crohn’s disease, posed a diagnostic dilemma. The development of oral, genital, and laryngeal ulcers, along with positive C3c and clinical response to colchicine supported the diagnosis. Differentiating BD from Crohn’s disease is critical due to implications for management and prognosis.

References

Image 1: endoscopic image of ileal ulcerations.
Image 2: endoscopic image of the ulceration on the aryepiglottic fold
Image 3: image of tongue ulceration

Introduction

In contrast to mucosal T1 rectal cancers with an R0 rate of up to 92% at centers, R0 resection may drop to 30% in case of deep sm infiltration due to thermal artefacts at the basal resection margin. TME often follows as completion surgery. Deep sm infiltration as isolated risk factor excluding L+, V+, G3 and Bd2-3 seems associated with a low risk of LN metastases of only 2.6%. Endoscopic Intermuscular Dissection (EID) is a new flexible endoscopic dissection technique with separation of the circumferential and longitudinal muscular layer. EID ideally provides a specimen incl. the entire submucosa and inner circumferential mp layer. 12 sequential EIDs were compared to 53 historical rectal ESDs with HGIEN or rectal cancer as hp. result.

Aims & Methods

Lesions with biopsy proven ADC or HGIEN of the rectum without endoscopic, EUS or clinical signs of deep local infiltration. 2 pat. included after neo-adjuvant RT/Ch th. 24 and 26 mo before with complete response and refusing definitive surgery. Both with local flat polyps (SSA (1) hyperplastic polyp / LGIEN adenoma (2). Endoscopy, EUS, MRI, CT and rectal digital examination without suspicion of local malignant infiltration. Pts were offered to prospectively undergo EID after extensive informed consent within a prospective protocol. All procedures were carried out under gen. anesthesia by an exp. interv. endoscopist with >1000 ESDs. Results of EID were compared to a historical collective of 53 cases with rectal ESD and a histological result of rectal cancer or HGIEN (08-2018 to 12-2021).

Results

From 11-2023 to 09-2024, 12 EIDs were carried out in 12 pts (6 f/ 6 m; mean 63 y; 34-83y). 09/12 lower rectum, 1/12 middle, 1/12 lower and middle, 1/12 upper rectum. 'En bloc' resection rate was 100%, R0 resection rate 89% for neoplasia / HGIEN. Histopathology: 3x ADC G2, 6x HGIEN, 3x LGIEN including both cases with neodajuvant RT/Ch. R0 resection was achieved in 2 of the 3 ADCs. Both with deep sm infiltration without any other risk factors. Tumor board: close clin. & imaging FU. In the 3rd ADC: TU infiltration of inner muscular layer (T2). Pat. underwent uneventful TME 10 d after EID. Clinical FU in all others. Length of hosp. stay 7.1 days. No serious major complications. All pts. closely followed with uneventful FU.
In the historical ESD group R0 resection was achieved in 100% of the HGIEN cases (45/45) but only in 3/8 lesions (37.5%) of cases with adenocarcinoma.

Conclusion

EID seems a new perspective for the endosc. resection of T1 rectal cancers and suspicious polyps in the rectum. More experience and a comparison to surgical local procedures (TAMIS etc.) is necessary for the final assessment of EID as new promising endoscopic technique.

References