Introduction

Gastro-oesophageal reflux disease (GERD), caused by reflux of stomach contents into the oesophagus, results in discomfort and pain. Evidence suggests reflux- induced oxidative stress in oesophageal epithelial cells may have a role in GERD pathogenesis and symptom development. High mobility group box 1 (HMGB1), a nuclear protein found in most cell types, is actively released in response to oxidative stress. HMGB1 binds to TLR2, TLR4, and RAGE, leading to downstream inflammatory signalling.

Aims & Methods

Our aim was to investigate the potential role of epithelial-derived HMGB1 in the context of GERD.
Oesophageal biopsy tissue was obtained from consented healthy volunteers (N=10) and GERD patients categorised as functional heartburn (FH; N=7), non-erosive reflux disease (NERD; N=13), and erosive reflux disease (ERD; N=11) based on clinical assessment. Oesophageal HMGB1 mRNA was assessed by RT-qPCR. Tissue was used to assess protein expression of HMGB1, TLR2, TLR4, and RAGE using immunohistochemistry (IHC). Healthy oesophageal biopsies were used to assess HMGB1 release ex vivo following synthetic refluxate challenge (pH2, 1mM deoxycholate (DCA), 1mg/mL pepsin). Cellular translocation of HMGB1 was assessed using immunofluorescence in NE-1 cells in response to acidic bile salts (pH4, 1mM DCA).

Results

HMGB1 mRNA and epithelial protein expression were consistent between healthy control and GERD patients. TLR2 and TLR4 were expressed primarily on epithelial cells with cell quantification revealing TLR4 to be the predominantly expressed epithelial receptor. The proportion of TLR4+ cells was higher in ERD compared to healthy controls (1.4% ± 0.43 vs 7.2% ± 2.567; p<0.05). In contrast, RAGE was expressed exclusively on CD45+ leukocytes – predominantly in GERD phenotypes. Many RAGE+ immune cells in GERD tissue were in close apposition to sensory CGRP+ nerve fibres. Incubating NE-1 cells with acidic bile salts (10mins), but not acid alone, induced HMGB1 translocation to the cytosol (nuclear:cytosolic HMGB1 ratios: pH7 = 2.42 ± 0.19; pH4 = 2.66 ± 0.07; pH4 + DCA = 1.416 ± 0.06; p=0.0003). Challenging oesophageal biopsies with synthetic refluxate (5mins) led to release of HMGB1 over 18 hours compared to paired biopsies (218 ± 57 vs 586 ± 220 pg/mL/mg; p<0.05).

Conclusion

HMGB1 released by oesophageal epithelial cells following reflux may contribute to inflammatory pathways in GERD, particularly via TLR4 and RAGE on epithelial and immune cells, respectively. This is of particular interest in PPI-refractory GERD, due to the exaggerated role of bile salts in HMGB1 release. Further, the close proximity of RAGE+ leukocytes and CGRP+ nerve fibres may represent a cross-talk between epithelial cells, immune cells, and sensory nerves. HMGB1 may therefore be a potential new treatment target for GERD.

Introduction

Data evaluating the utility of Blue light Imaging (BLI) and Linked Color Imaging (LCI) in the diagnosis of gastric intestinal metaplasia (IM) and atrophic gastritis (AG) is limited.

Aims & Methods

We aimed to evaluate and compare the diagnostic accuracy of BLI and LCI without magnification for the detection of IM and AG.
Single centre prospective study involving consecutive patients aged ≥18 years undergoing diagnostic upper gastrointestinal endoscopy (UGIE), endoscopic follow-up of intestinal metaplasia or gastric cancer screening. Exclusion criteria: previous gastrectomy, contraindication to UGIE due to comorbidities, no gastric mucosal biopsies, refusal of consent. Endoscopy was initially performed with white light image (WLI), followed by BLI and LCI. Standardized photodocumentation of stomach was performed with WLI, BLI and LCI. Imaging features suggestive of IM: lavender color sign and whitish flat elevation with LCI, and light blue crest and white opaque substance with BLI. EGGIM and Kimura-Takamoto Classification (KTC) were applied when IM and AG were suspected. Systematic random biopsies of the antrum, incisura angularis and corpus along with targeted biopsies of suspicious gastric mucosal lesions were obtained. Histology was considered gold standard. Performance of endoscopic imaging in the detection of IM, AG and EGC was evaluated.
Initially, 134 patients were evaluated and 64 were excluded: previous gastrectomy-22, pending histology-20, non-BLI imaging-15, intolerance to UGIE-3, refusal of consent-1, esophageal stenosis-1 and contra-indication to biopsies-2. Final sample included 70 patients.
Qualitative data expressed as percentage were compared with Chi-square test. A p value of <0.05 was considered significant.

Results

Median age was 56 (19-86), with 49 (63%) female. There was family history of gastric cancer in 12(15%) and history of smoking in 35 (44%).
Histological AG was found in 15 (19%) and IM in 20 (26%) patients. WLI was suggestive of IM in 14(20%), confirmed histologically in 9 (64%). IM was suspected by LCI and BLI in 24 (34%) and 23 (32%) cases, confirmed by histology in 16 (67%) and 17 (74%), respectively.
WLI classified 56 (71%) as EGGIM 0 and after LCI and BLI, 10 (18%) and 8 (15%) of these cases had EGGIM 1 or 2. In 10 patients, EGGIM 1-2 with WLI, only 1 was upgraded to EGGIM 3-4 with LCI and BLI. In 3 (4%) EGGIM 3-4 with WLI, after LCI and BLI,1 had extensive IM (EGGIM 6). Among 19(24%) patients EGGIM 1-2 with LCI, 3(16%) had EGGIM 0 with BLI.
Atrophy was suspected by WLI and LCI in 9(12%) and 15(21%) patients, confirmed by histology in 6(67%) and 8(53%) cases, respectively. According to KTC, 5 (6%) were classified as C1, 2 (3%) as C2 and 4 (5%) as O3 with WLI. With LCI images, 8 (10%) were classified as C1, 3(4%) as C2 and 4(5%) as O3. The sensitivity (Sens), specificity (Spec), accuracy, positive predictive value (PPV), negative predictive value (NPV) of WLI, BLI and LCI in detecting AG and IM are shown in table 1.


Table 1. Sens, Spec, accuracy, PPV and NPV in detecting AG and IM with WLI, LCI and BLI.

Conclusion

Both BLI and LCI are promising advanced endoscopic imaging techniques with BLI having higher accuracy than LCI in detection of IM.

References

1. Chen H, Liu Y, Lu Y, Lin X, Wu Q, Sun J, et al. Ability of blue laser imaging with magnifying endoscopy for the diagnosis of gastric intestinal metaplasia. Lasers Med Sci. 2018 Nov 1;33(8):1757–62.
2. Ono S, Abiko S, Kato M. Linked color imaging enhances gastric cancer in gastric intestinal metaplasia. Vol. 29, Digestive Endoscopy. Blackwell Publishing; 2017. p. 230–1.
3. Ono S, Kato M, Tsuda M, Miyamoto S, Abiko S, Shimizu Y, et al. Lavender Color in Linked Color Imaging Enables Noninvasive Detection of Gastric Intestinal Metaplasia. Digestion. 2018 Nov 1;98(4):222–30.
4. Zhang G, Zheng J, Zheng L, Yu S, Jiang C, Lin W, et al. Gastric intestinal metaplasia assessment between linked color imaging based on endoscopy and pathology. Scand J Gastroenterol. 2021;56(1):103–10.
5. Shu X, Wu G, Zhang Y, Wang Y, Zheng Y, Guo Q, et al. Diagnostic value of linked color imaging based on endoscopy for gastric intestinal metaplasia: a systematic review and meta-analysis. Ann Transl Med. 2021 Mar;9(6):506–506.
6. Esposito G, Pimentel-Nunes P, Angeletti S, Castro R, Libânio D, Galli G, et al. Endoscopic grading of gastric intestinal metaplasia (EGGIM): A multicenter validation study. Endoscopy. 2019;51(6):515–21.

Introduction

Recent societal guidelines suggest there is no role for hydrogen and methane breath testing (HMBT) to exclude small intestinal bacterial overgrowth (SIBO) in patients with diarrhoea predominant irritable bowel syndrome (IBS) and to treat symptoms with rifaximin empirically^1,2. However, a positive result for SIBO with lactulose HMBT has been shown to predict more favourable outcomes to rifaximin in patients with diarrhoea predominant IBS³. We wanted to investigate if symptoms and medical history can predict lactulose HMBT outcome hence justifying treatment of SIBO without a formal diagnosis.

Aims & Methods

A large questionnaire-based study was conducted in over 1000 patients of which 731 completed lactulose HMBT. The 26-item questionnaire included questions about medical history, symptoms, and pattern of symptoms, and we used this to identify any positive predictors for SIBO on HMBT. A positive lactulose HMBT was determined by a rise of ≥20 ppm in breath hydrogen from baseline within 90 minutes³. Breath samples were analysed using gas chromatography. Associations and predictors were calculated using chi square tests and logistic regression, respectively.

Results

Bloating (93.6%), abdominal pain (87.3%), and diarrhoea (80.3%) were the most common symptoms reported by those with a positive result for SIBO, but their duration, frequency and onset were no different to patients with a negative result (P > 0.05). There were no positive predictors for SIBO on lactulose HMBT based on symptoms, medications or medical history except for chronic low ferritin (P = 0.025).

Conclusion

This large questionnaire study has demonstrated that symptoms and medical history cannot predict HMBT outcomes for SIBO. Therefore, treatment of SIBO without a diagnosis confirmed on HMBT may lead to unnecessary antibiotic use and costs.

References

1. Vasant DH, Paine PA, Black CJ, Houghton LA, Everitt HA, Corsetti M, Agrawal A, Aziz I, Farmer AD, Eugenicos MP, Moss-Morris R, Yiannakou Y, Ford AC. British Society of Gastroenterology guidelines on the management of irritable bowel syndrome. Gut. 2021 Jul;70(7):1214-1240.
2. Savarino E, Zingone F, Barberio B, Marasco G, Akyuz F, Akpinar H, Barboi O, Bodini G, Bor S, Chiarioni G, Cristian G, Corsetti M, Di Sabatino A, Dimitriu AM, Drug V, Dumitrascu DL, Ford AC, Hauser G, Nakov R, Patel N, Pohl D, Sfarti C, Serra J, Simrén M, Suciu A, Tack J, Toruner M, Walters J, Cremon C, Barbara G. Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility. United European Gastroenterol J. 2022 Jul;10(6):556-584.
3. Rezaie A, Heimanson Z, McCallum R, Pimentel M. Lactulose Breath Testing as a Predictor of Response to Rifaximin in Patients With Irritable Bowel Syndrome With Diarrhea. Am J Gastroenterol. 2019 Dec;114(12):1886-1893.

Introduction

Dietary and lifestyle recommendations are the cornerstones of the treatment of GERD. However, the evidence of the efficacy of those recommendations is lacking. We performed a retrospective analysis of the GISTAR study¹ participants evaluating the symptoms of GERD and dietary and lifestyle parameters developing a tool for predicting GERD symptoms based on the aforementioned criteria.

Aims & Methods

The aim of the study was to analyse the factors pointing to GERD symptoms through the use of data mining and decision tree classifier.
Methods: GERD diagnosis was evaluated using a self-assessment questionnaire ². Dietary, demographic and lifestyle data were collected within the GISTAR study protocol¹. 3340 40-64 year old participants from the GISTAR study were included in the analysis. 1670 of them did not have GERD symptoms. 41 attributes describing demographic, lifestyle, and dietary habits were used for these respondents to induce a decision tree classification model using Orange Data Mining software³.

Results

Fried potatoes including French fries were the most predictive factor of GERD symptoms (65.3% with symptoms; 1516 from 2321), especially for females (82.6%; 1048/1228). This was more pronounced in the group who consumed sweets once per week (87.2%, 950/1090). In males, who consumed fried potatoes, the next most important factor was the consumption of sweets (46.3%, 431/930).
For participants who didn’t consume fried potatoes (14.6%; 147/1008), 1-3 cups of green tea (37.9%; 66/174) and male gender (71.4 % 20/28) were predictors of GERD symptoms.
The accuracy of the decision tree model was: sensitivity (74.8%), precision (75.6%), specificity (75.9%) and AUC (0.841%).

Conclusion

Fried potatoes, female gender and consumption of sweets are the risk factors predicting the diagnosis of GERD. None of the lifestyle factors were displayed as significant.

References

1. Leja M, Park JY, Murillo R, et al. Multicentric randomised study of Helicobacter pylori eradication and pepsinogen testing for prevention of gastric cancer mortality: the GISTAR study. BMJ Open 2017;7:e016999. doi: 10.1136/bmjopen-2017-016999
2. Jones R, Junghard O, Dent J, Vakil N, Halling K, Wernersson B, Lind T. Development of the GerdQ, a tool for the diagnosis and management of gastro-oesophageal reflux disease in primary care. Aliment Pharmacol Ther. 2009 Nov 15;30(10):1030-8. doi: 10.1111/j.1365-2036.2009.04142.x. Epub 2009 Sep 8. PMID: 19737151.
3. Demsar J, Curk T, Erjavec A, Gorup C, Hocevar T, Milutinovic M, Mozina M, Polajnar M, Toplak M, Staric A, Stajdohar M, Umek L, Zagar L, Zbontar J, Zitnik M, Zupan B (2013) Orange: Data Mining Toolbox in Python, Journal of Machine Learning Research 14(Aug): 2349−2353.