Introduction

Pathological esophageal acid exposure may persist in patients with Barrett’s esophagus (BE) despite standard proton pump inhibitor (PPI) therapy and symptom control, although current guidelines recommend at least standard-dose PPI for all patients with BE.¹

Aims & Methods

Aim was to evaluate the role of esophageal function testing in assessing acid exposure in BE patients on PPI therapy and in predicting neoplastic progression. We conducted a multicenter retrospective study including asymptomatic BE patients (defined by GerdQ total score <8 and a score of 0 on the first GerdQ item) who underwent high-resolution manometry and 24-hour pH impedance monitoring while on various PPI regimens. Maximal PPI therapy included esomeprazole 40 mg, pantoprazole 40 mg, rabeprazole 20 mg, or lansoprazole 30 mg, all administered twice daily. All other regimens were considered standard dosing. Index upper endoscopy with biopsies was performed under the same therapeutic regimen. Histologically, presence and degree of neoplasia (all confirmed by a second pathologist) was recorded. Acid exposure time (AET) <4% was defined as adequate acid control; AET >6% as pathological reflux. Predictors of pathological reflux and neoplasia were assessed using logistic regression analysis.

Results

A total of 135 patients (2016-2025) were included (mean age 58 ± 15 years; 73% male). Median BE length was C1 (range 0–3 cm) and M2 (range 1–5 cm), with 41% (n=56) classified as having long-segment BE. Sixty-seven patients (50%) were on standard-dose PPI. Pathological reflux was identified in 37 patients (27%), of whom 25 (67%) were on standard-dose therapy. Fourteen patients (10%) had borderline AET values (4–6%). Among the 84 patients (62%) with adequate acid control, 33 (39%) were taking standard-dose PPI. On multivariable analysis, standard-dose PPI (OR 3.04; 95% CI 1.34–6.89; p=0.008) and type III esophagogastric junction morphology (OR 2.52; 95% CI 1.01–5.01; p=0.047), consistent with manometric hiatal hernia, were independently associated with pathological reflux. Non-dysplastic BE was found in 112 patients, while 13 (10%) had neoplasia at index endoscopy (8 low-grade dysplasia, 3 high-grade dysplasia, 2 intramucosal adenocarcinoma). Pathological reflux was the only independent predictor of neoplasia (OR 10.41; 95% CI 2.65–41.26; p<0.001).

Table 1. Logistic regression analysis for factors associated with neoplasia on index endoscopy.

Conclusion

Nearly one-third of asymptomatic BE patients exhibit pathological reflux on pH-monitoring despite PPI treatment, predominantly among those on standard-dose and with manometric hiatal hernia. Nonetheless, adequate acid control is achieved in over one-third of patients on standard PPI therapy. Pathological reflux is associated with a 10-fold increased risk of neoplasia.

References

1. Shaheen NJ, Falk GW, Iyer PG, et al. Diagnosis and Management of Barrett's Esophagus: An Updated ACG Guideline. Am J Gastroenterol. 2022;117(4):559-587.

Introduction

Spasmolytic polypeptide expressing metaplasia (SPEM) is a cell repair lineage and is a very important phenotype of gastric mucosal injury and precancerous lesion.
Previously, parietal cells loss is considered as the first step and followed with chief cells transdiffernation to induce SPEM. But whether chief cells initial loss cause SPEM
needs to be further investigation. Acidic mammalian chitinase (CHIA) belongs to the 18 glycosidase family and is highly expressed in the chief cells. Our previous study showed that CHIA deficiency in the chief cells is the key event to induce SPME to progress to gastric cancer (Liu et al., DDW 2023 and 2024). However, the molecular role of CHIA in the development of SPEM is need further investigated.

Aims & Methods

Electron microscopy, qRT-PCR and single-cell sequencing (scRNA-seq) technology, as well as histopathological and immunofluorescence (IF) stainning with specific markers were performed in chief cells specific CHIA knockout mouse model (CHIA^rox/rox-GIF-Dre) and wild-type mice(CHIA^rox/rox), and in CHIA over - expression mice (CHIA ^rox/rox - GIF - Dre + rAAv - CHIA) and the control group (CHIA ^rox/rox - GIF - Dre + rAAv - control).

Results

Compared with CHIA^rox/rox mice, histological analysis and scRNA-seq technology data showed that loss of chief cells with increased M2 macrophage infiltration and final SPEM formation, but remaining of parietal cells in CHIA^rox/rox-GIF-Dre mice. Electron microscopy showed CHIA deficiency in mice resulted in endoplasmic reticulum was dilated and swollen, as well as the mitochondrial membrane was discontinuous of chief cells, followed with the accumulation of endoplasmic reticulum stress marker, including PERK, XBP-1, eIF2α/P-eIF2α, and GRP78, together with upregulation of pyroptosis-related marker, including NLRP3, ACS, GSDMD, NEK7, Caspase1, Caspase11, IL-1β, and IL-18, which was detected by qRT-PCR. These data indicating that target CHIA deletion caused chief cells pyroptosis. Furthermore, qRT-PCR analysis showed that CHIA deficiency caused the activation of IL33/IL-13 circuit in the mucosa of mice. Moreover, double immunofluorescence staining confirmed that upregulation and colocalization of IL-33 induced M2 macrophage polarization markers, including F4/80 and CD163⁺ with NLRP3 in the base of gastric mucosal of CHIA^rox/rox-GIF-Dre mice when compared with CHIA^rox/rox mice.Notably, CHIA ^rox/rox - GIF - Dre + rAvv - CHIA mice reversed the above process compared with controls.

Conclusion

Chief cells specific CHIA deficiency resulted in endoplasmic reticulum stress mediate NLRP3 inflammasome activation to induce chief cells proptosis.
Chief cells initial loss is sufficient and the key step to activate IL-33/ST2-M2 macrophage polarization axis to induce SPEM, which is independent of parietal cells loss.