Introduction

Endoscopic resection techniques, particularly endoscopic submucosal dissection (ESD), are increasingly adapted for lesions located beyond the gastrointestinal tract, including the hypopharynx. Atypical lesions in the pyriform sinus are uncommon and pose significant diagnostic and therapeutic challenges due to their anatomical complexity and limited endoscopic experience. We present a rare case of a flat mucosal lesion in the left pyriform sinus, initially suggestive of low-grade dysplasia (LGD) managed by ESD for excisional biopsy. Our optical diagnosis and resection strategy were based on a previously published case by Di et al., who demonstrated the feasibility of modified ESD in the hypopharyngeal region. (BMC Cancer 17, 712 (2017).

Aims & Methods

A 28-year-old female presented with upper abdominal pain and was referred for diagnostic esophagogastroduodenoscopy (EGD). She was a non-smoker with no relevant oncological family history. Routine examination of the esophagus, stomach, and duodenum was unremarkable. However, careful inspection of the hypopharynx revealed a flat elevated lesion (Paris 0-IIa), approximately 10×10 mm in size, with a demarcated border, located in the left pyriform sinus. Under narrow-band imaging (NBI) with dual focus, intrapapillary capillary loop (IPCL) pattern type IV was observed, raising suspicion for low-grade neoplasia or high-grade neoplasia. The lesion was photo-documented, and the patient was referred for therapeutic resection.
ESD was performed under general anesthesia. En bloc excision was achieved without adverse events; the resection time was 12 minutes.

Results

Histopathologic analysis revealed stratified non-keratinizing squamous epithelium overlying subepithelial lymphoid tissue, consistent with mucosa-associated lymphoid tissue (MALT). Areas of lymphoid follicular hyperplasia with fused follicles were present. The epithelium was non-dysplastic, with regenerative changes and mild intraepithelial lymphocytosis. Immunohistochemistry revealed non-block-type p16 staining, and Ki-67 expression was limited to the basal layer. No morphological or immunohistochemical evidence of high-grade squamous intraepithelial lesion (HSIL) was found.
The patient experienced mild local discomfort for two weeks post-procedure, controlled with ibuprofen. Follow-up endoscopy at one month confirmed complete healing with no recurrence.

Conclusion

This case highlights the growing applicability of advanced endoscopic techniques beyond the gastrointestinal tract and emphasizes the diagnostic limitations of optical assessment in small hypopharyngeal lesions. Despite features suggestive of squamous dysplasia, accurate diagnosis relied on excisional biopsy. ESD proved to be a safe and effective therapeutic option in this anatomically challenging location.

References

Di, L., Fu, KI., Xie, R. et al. A modified endoscopic submucosal dissection for a superficial hypopharyngeal cancer: a case report and technical discussion. BMC Cancer 17, 712 (2017). https://doi.org/10.1186/s12885-017-3685-7

Introduction

The cause of Crohn’s Disease (CD) remains unclear; however evidence suggests that dietary factors play a key role. With a rising incidence and no definitive cure, identifying modifiable risk factors is critical in preventing CD development. We aimed to study the association between fermentable dietary fibre intake and the future development of CD in an at-risk population.

Aims & Methods

Participants were recruited as part of the Crohn’s and Colitis Canada GEM study, a prospective cohort study of healthy first-degree relatives of patients with CD. At enrolment, a validated food frequency questionnaire was administered. Pectin, β-glucan, inulin, fructooligosaccharides (FOS), and arabinoxylan intake were quantified, and values energy-adjusted. Survival analysis was used to test the association between intake of fibre subtypes and risk of CD development. Generalized estimating equation tested the association between fibre intake and baseline impaired intestinal permeability (fractional urinary excretion of lactulose to mannitol ratio (LMR) >0.025); subclinical gut inflammation (faecal calprotectin (FCP) >250 μg/g); and faecal microbiome composition via 16s rRNA sequencing.

Results

76 of the 2,659 participants developed CD with a median follow-up of 8.9 years (IQR=5.7-12.3). Median age at recruitment was 17 years (IQR=12-25). 47% were male. Higher intake of inulin (HR = 0.78; 95% CI=0.61–0.99; p=0.04) and β-glucan (HR = 0.78; 95% CI=0.61–0.99; p=0.04) were associated with a reduced risk of CD development. No fibre subtype was associated with a higher risk of CD development. Lower intake of pectin, inulin, FOS and β-glucan was associated with impaired intestinal permeability (0.005<p<0.04). Lower inulin intake was associated with high FCP levels (p = 0.046). Higher pectin intake was associated with increased alpha diversity of faecal microbiome (p = 0.028). Higher inulin, FOS and pectin intake was associated with a shift in microbial taxa previously shown to be protective against CD onset in the GEM cohort; a reduction in Ruminococcus torques and an increase in NK4A214 group (phylum Firmicutes) presence (3.25×10⁻¹⁰<q<0.04).

Conclusion

This study demonstrates that dietary intake of fermentable fibre subtypes is associated with a reduced risk of CD development as well as with pleiotropic changes in CD risk biomarkers including microbiome, intestinal permeability, and subclinical inflammation. This suggests that the potential benefit of fermentable fibres on CD risk may involve changes in barrier function, and microbiome composition and function. Targeted interventions based on these findings could prove effective in preventing the onset of CD.

Introduction

Microplastic particles (MPs), defined as plastic fragments smaller than 5 mm, are pervasive pollutants that accumulate in ecosystems and the human food chain (1). Literature points at various health risks, including the induction of carcinogenesis (2). Emerging evidence from animal models (3) suggests that MPs may influence the gut microbiome, but the impact on the human gut microbiome remains poorly understood.

Aims & Methods

This study aimed to evaluate how various MP types influence gut microbial composition and metabolism using an ex vivo bioreactor model, with a focus on exploring potential carcinogenic effects arising from MP–microbiome interactions.
Stool samples from healthy donors were used to inoculate bioreactor cultures, which were maintained under anaerobic conditions for five days with daily nutrient feeding. These cultures were exposed to five common MP types—polystyrene (PS), polypropylene (PP), low-density polyethylene (LDPE), poly(methyl methacrylate) (PMMA), and polyethylene terephthalate (PET)—at concentrations mimicking both estimated human exposure (4) and higher doses to assess dose-dependence. Cell viability and total bacterial counts, as well as culture pH, were measured throughout the experiment. To further explore potential microbiome and metabolic alterations, 16S rRNA gene sequencing and targeted metabolomics were performed.

Results

MP exposure did not lead to significant changes in total or viable bacterial cell counts. However, MP-treated cultures exhibited a consistent and significant decrease in pH compared to controls, suggesting changes in microbial metabolic activity. Microbiome sequencing revealed plastic-type-dependent alterations in microbial composition, with certain bacterial taxa increasing or decreasing in abundance depending on the MP type. These shifts occurred across multiple genera within diverse families, including Lachnospiraceae, Oscillospiraceae, Enterobacteriaceae, and Ruminococcaceae, with the majority of changes occurring withing the phylum Bacillota. These compositional changes were accompanied by shifts in the metabolomic profiles, some of which correlated with the observed pH changes. Several plastic types induced changes in valeric acid levels, while individual MP types were associated with alterations in distinct metabolites such as uracil, lactic acid, and acetic acid.

Conclusion

This study demonstrates that MPs can affect gut microbial activity and metabolism without significantly altering overall bacterial abundance in the short term. The variation in microbiome response across plastic types highlights the complexity of MP-microbiome interactions. Changes in faecal pH are known to be associated with various gastrointestinal diseases (5). Interestingly, some of the MP-induced changes in microbial composition resembled patterns linked to diseases such as depression and colorectal cancer. In contrast, other changes showed patterns that differed from those typically associated with conditions like Parkinson’s disease and irritable bowel syndrome, highlighting the complexity of these associations and the dependency on the context. The bioreactor model provided a controlled environment for identifying direct MP-microbiome interactions; however, in humans, additional factors like diet, immune response, and individual microbiome variations play a role in determining long-term effects. Exposure duration may also play a critical role in shaping the extent and nature of microbiome alterations (6), underscoring the need for further research into the effects of chronic MP exposure and associated health risks.

References

(1) Mamun, A. A., Prasetya, T. A. E., Dewi, I. R., & Ahmad, M. (2023). Microplastics in human food chains: Food becoming a threat to health safety. The Science of the total environment, 858(Pt 1), 159834. https://doi.org/10.1016/j.scitotenv.2022.159834
(2) Kumar, R., Manna, C., Padha, S., Verma, A., Sharma, P., Dhar, A., Ghosh, A., & Bhattacharya, P. (2022). Micro(nano)plastics pollution and human health: How plastics can induce carcinogenesis to humans?. Chemosphere, 298, 134267. https://doi.org/10.1016/j.chemosphere.2022.134267
(3) Hirt, N., & Body-Malapel, M. (2020). Immunotoxicity and intestinal effects of nano- and microplastics: a review of the literature. Particle and fibre toxicology, 17(1), 57. https://doi.org/10.1186/s12989-020-00387-7
(4) Senathirajah, K., Attwood, S., Bhagwat, G., Carbery, M., Wilson, S., & Palanisami, T. (2021). Estimation of the mass of microplastics ingested - A pivotal first step towards human health risk assessment. Journal of hazardous materials, 404(Pt B), 124004. https://doi.org/10.1016/j.jhazmat.2020.124004
(5) Yamamura, R., Inoue, K. Y., Nishino, K., & Yamasaki, S. (2023). Intestinal and fecal pH in human health. Frontiers in Microbiomes, 2, 1192316.
(6) Yin, L., Yang, M., Teng, A., Ni, C., Wang, P., & Tang, S. (2025). Unraveling Microplastic Effects on Gut Microbiota across Various Animals Using Machine Learning. ACS nano, 19(1), 369–380. https://doi.org/10.1021/acsnano.4c07885

Introduction

TPM502 is a mixture of three distinct nanoparticles, each coupled with one celiac disease (CeD)-relevant gluten peptide, representing immunodominant and deamidated CD4⁺ T cell epitopes. TPM502 targets liver sinusoidal endothelial cells, which are unconventional antigen-presenting cells capable of inducing antigen-specific tolerance.

Aims & Methods

TCeD21 (NCT00565136) was a phase 2a double-blind, randomized, placebo-controlled study in HLA-DQ2.5-positive adults with confirmed CeD on a gluten-free diet. Patients achieving a predefined IL-2 response to a single dose (6 g) gluten challenge (GC1) were randomized into four cohorts to receive two intravenous infusions with escalating doses of TPM502 or placebo on day (D) 1 and D15. The GC was repeated 7 days after the second TPM502 dose (GC2). Peripheral blood mononuclear cells collected from each patient at predefined timepoints were analyzed by high-dimensional (30-color) flow cytometry, before and after HLA-DQ2.5-gliadin-specific tetramer (tet) enrichment, using surface staining for various phenotypic markers. The study aimed to characterize the phenotypes of gluten-specific T cells in CeD patients before and after TPM502 treatment to assess its immunomodulatory effects.

Results

Samples from 36 patients completing the study (12 placebo, 24 TPM502) were analyzed across five timepoints. In the placebo group, tet⁺ CD45RA^-CD62L^-CD4⁺ T (Ttet) cells increased after both GCs. By contrast, the TPM502 cohorts exhibited elevated Ttet cell numbers before GC2 (D22) but showed limited expansion afterward (D29), suggesting that TPM502 treatment may prevent further activation-induced expansion. Moreover, the frequency of activated Ttetcells—indicated by activation markers CD38, ICOS, and OX40—significantly decreased across all TPM502 dose levels after GC2 compared to the placebo group (fold change D22 vs D29, all p < 0.0001 by Kruskal-Wallis test). Notably, the diminished gluten response of Ttet cells post-treatment was accompanied by enhanced expression of co-inhibitory receptors TIGIT and PD-1 (D-21 vs D29, p < 0.0001), along with reduced CD127 expression (p < 0.01), indicative of decreased cell survival. These phenotypic changes, consistent with T cell exhaustion or anergy, persisted until study end and were visibly distinct from those in the placebo group, as illustrated by the heatmap of delta log-transformed flow cytometry data of Ttet cells across timepoints, clustered hierarchically. Gliadin-specific CD4⁺ regulatory T cells (CD25⁺CD127^- Ttet) and CD39⁺ Ttet cells increased post-treatment at the highest TPM502 dose, suggesting the induction of regulatory states in these T cells. Moreover, pre-enriched samples showed reduced activation of αEβ7⁺ γδ⁺ and CD8⁺ Tcells after GC2 at the highest TPM502 dose, suggesting potential bystander effects.

Conclusion

Data from the first longitudinal tetramer-based flow cytometry analysis in CeD patients provide evidence that TPM502 induces antigen-specific tolerance through T-cell immunomodulation. These results corroborate other pharmacodynamic outcomes generated in this study, including a significant and dose-dependent reduction in ex vivo IL-2 and IFN-γ secretion by gluten-specific T cells after treatment. In addition to a good safety and tolerability profile of TPM502, this nanoparticle-mediated induction of antigen-specific tolerance may provide a novel therapeutic avenue to treat celiac disease.