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Notch Signaling is Critical for Gastric Epithelial Cell Homeostasis, Regulating Proliferation, Gastric Antral Stem Cell Marker Expression and Cell Lineage Determination
AGA Abstracts
using 24 hr esophageal impedance pH monitoring. Methods: 39 patients (29 F, age 47 ±13 yrs) with and without globus symptom who were suspected of GERD underwent 24 hr pHimpedance monitoring following esophageal manometry during off therapy. All patients had a negative upper endoscopy before the study. The present of typical reflux symptoms, upper gastrointestinal symptoms and extraesophageal symptoms were evaluated using a symptom questionnaire. Each acid or non-acid reflux event was analyzed visually for temporal relationship with swallows, gas/liquid composition of the refluxate, proximal extent and bolus contact time. Reflux events during meal ingestion were excluded. Acid refluxes defined as typical impedance changes associated with pH fell below 4 for more than 4 seconds . Nonacid refluxes were defined as the impedance changes associated with pH remaining more than 4. Results: 19, 7, and 13 patients had reflux-like dyspepsia, typical reflux and chronic idiopathic ENT problems as their main symptoms, respectively. Nineteen patients (48.7%) had globus sensation. 31.6% of patients with globus sensation had positive pH test (% time pH<4 at lower esophagus >4.5%) which was similar to patients without globus sensation (25%) p>0.05. 587 acid reflux episodes and 248 non-acid reflux episodes were identified. The proportion of acid/non-acid reflux number was similar between patients with and without globus sensation (5.4±7.9 vs 2.3±2.1, p>0.05). Non acid reflux episodes in patients with globus sensation had significantly more prolonged bolus contact time compared to patients without globus sensation (18.4±9.0 vs 11.9±6.1 seconds, p =0.03). Furthermore, there were more prevalence of immediate swallowing (within 15 seconds) after these nonreflux episodes in patients with globus sensation than patients without globus sensation (53.8±31.4 % vs 30±21.3%, p=0.01). Bolus contact time during acid reflux episodes, immediate swallowing rate after acid reflux episodes, proximal acid and non-acid reflux extension, proportion of liquid/mixed liquid-gas refluxate were similar between patients with and without globus sensation (p>0.05). Conclusions: Non-acid reflux episodes occurred in similar proportion between suspected NERD patients with and without globus sensation. However, the non-acid reflux episodes in patients with globus sensation had longer bolus contact time and induced more swallowing response. This study suggests the possible role of nonacid reflux in the pathogenesis of globus sensation in NERD patients with esophageal or extraesophageal symptoms.
Mo1689 The Effects of Gas Reflux on the Perception of Proximal Reflux in Patients With Non-Erosive Reflux Disease (NERD) Who Have a Positive Symptom Index While on Proton Pump Inhibitor Therapy Noriyuki Kawami, Katsuhiko Iwakiri, Hirohito Sano, Yuriko Tanaka, Mariko Umezawa, Seiji Futagami, Yoshio Hoshihara, Choitsu Sakamoto Background: We have reported that the proximal extent of refluxate is an important factor in determining the perception of reflux in NERD patients who have a positive symptom index (SI) on double-dose PPI therapy, irrespective of the acidity of the refluxate and the duration of proximal reflux episodes (Digestion 2010). The effect of gas reflux however, as a determinant of the perception of reflux, is not clear. Methods: 11 NERD patients with persistent symptoms, despite double-dose PPI therapy, were included in this study. All patients had a positive SI, which was determined by ambulatory 24-hour combined impedance-pH monitoring. Reflux episodes were identified and classified as acid, weakly acidic or weakly alkaline reflux and were considered symptomatic if patients recorded a symptom within 5 min. after a reflux episode. A proximal reflux episode, which reached 15-17cm above the LES, was classified as liquid reflux or mixed reflux. Furthermore, with regard to mixed proximal reflux episodes, the proportion of symptomatic reflux episodes was evaluated at either 5-9cm or 15-17 cm above the LES where the gas reached. Results: In the 11 patients with a positive SI, 914 liquid-containing reflux episodes were recorded. 61 (6.7%) reflux episodes were symptomatic reflux episodes but most (88.5%) symptomatic reflux episodes were weakly acidic reflux. The proportion of symptomatic reflux episodes at 5cm, 7cm, 9cm, 15cm and 17cm above the proximal margin of the LES was 1.7% (3/177), 3.8% (7/186), 6.7% (14/208), 13.6% (12/88) and 10.6% (25/255), respectively. Proximal reflux is significantly more likely to be associated with reflux symptoms, irrespective of the acidity of the refluxate or the duration of the proximal reflux episodes. Amongst the 914 liquidcontaining reflux episodes, 345 (38.0%) were proximal reflux, 206 (59.7%) were liquidonly reflux and 139 (40.3%) were mixed (gas-liquid) reflux. There was no difference in the proportion of symptomatic proximal reflux episodes between liquid-only (13.1%) and mixed (12.1%) reflux episodes. The proportion of symptomatic mixed proximal reflux episodes, in which gas reached 5-9cm above the LES, was 10.0% and 10.6% where gas reached 1517cm above the LES. There was no difference in the proportion of symptomatic reflux episodes between the two. Conclusions: In NERD patients, who have a positive SI on doubledose PPI therapy, there was no effect of gas reflux on the perception of proximal reflux. Mo1690
Mo1688
Notch Signaling is Critical for Gastric Epithelial Cell Homeostasis, Regulating Proliferation, Gastric Antral Stem Cell Marker Expression and Cell Lineage Determination Elise Demitrack, Kelli L. VanDussen, Linda C. Samuelson
The Effect of Cholecystectomy on Gastroesophageal Reflux Symptoms: A Prospective Controlled Study Rukiye Vardar, Suleyman Karakose, Tahsin Tekeli, Sinan Ersin, Serhat Bor
BACKGROUND: Although Notch signaling is known to be a critical regulator of cellular proliferation and cell lineage determination in intestine and other tissues, its role in gastric tissue homeostasis has not been reported. Therefore, the goal of this study was to investigate a potential role for Notch signaling in regulation of antral stem cells, epithelial cell proliferation and lineage commitment in the stomach. METHODS: C57BL/6 mice were treated with vehicle (DMSO) or the gamma-secretase inhibitor (GSI) DBZ (30 μmol/kg daily for 5 days) to globally block Notch signaling, and stomach was collected on the sixth day for histological and gene expression analyses. Gastric tissue was analyzed for markers of mature epithelial cell lineages, including surface mucous (Muc5AC), parietal (H+, K+-ATPase), chief (intrinsic factor), endocrine (chromogranin A and gastrin), and glandular mucous (GSII lectin) cells. Expression of the gastric antral stem cell marker Lgr5 was analyzed by quantitative realtime PCR (qPCR). Apoptosis was detected by caspase-3 staining. Proliferation was measured in tissue sections by morphometric analysis of Ki67 staining and In Vitro by measuring growth of human gastric cancer cell lines AGS and MKN45 after treatment with the GSI DAPT (10 μM). RESULTS: In the gastric corpus, surface mucous, parietal, and endocrine cell lineages were similar in DBZ-treated and vehicle-treated mice. In the gastric antrum, however, DBZ treatment induced an apparent cell fate change, as the normally corpusspecific chief cell marker intrinsic factor was activated in cells in the base of the antral glands, resulting in cells that co-express GSII and intrinsic factor similar to transition cells in the gastric corpus. In response to DBZ treatment, cellular proliferation (cell number per nm2) in both the gastric corpus (0.4 ± 0.05 [vehicle] vs. 0.1 ± 0.05 [DBZ]) and antrum (1.7 ± 0.2 [vehicle] vs. 0.9 ± 0.2 [DBZ]) was significantly reduced. The importance of Notch for gastric cell proliferation was also shown by reduced growth of DAPT-treated AGS and MKN45 cells. Reduced proliferation with GSI treatment suggested that Notch signaling regulates gastric stem or progenitor cells. Accordingly, expression of the antral stem cell marker Lgr5 was markedly reduced in DBZ-treated antral tissue. Furthermore, analysis of cellular apoptosis through activated caspase-3 immunostaining revealed apoptotic epithelial cells in the base of the antral glands where the Lgr5-expressing stem cells reside. CONCLUSION: Notch signaling is crucial to maintain gastric epithelial cell homeostasis by regulating cell proliferation in both corpus and antrum and cell lineage commitment in the antrum. Notch regulation of deep antral gland cell apoptosis and expression of Lgr5 suggests that Notch signaling is required to sustain gastric antral stem cells.
BACKGROUND: It is claimed that gastroesophageal reflux disease (GERD) increases following cholecystectomy. However prospective and comparative studies about the effect of cholecystectomy on gastroesophageal reflux symptoms are very limited and contradictory. We aimed to prospectively compare pre- and postsurgical changes in the prevalence of reflux symptoms on patients with cholecystectomy and inguinal hernia repair surgery as controls. METHODS: We recruited 176 patients scheduled to undergo elective cholecystectomy (study group, n= 126) or inguinal hernia repair (controls, n=50) at two hospitals. Both groups filled out the validated GERD questionnaire 1 to 5 days prior the operation including demographic characteristics, upper gastrointestinal symptoms, drug, smoking and alcohol habits with 54 questions. A hundred and ten patients (78 from cholecystectomy group) who could be reached filled out again same questions 6-36 months following surgery. Changes in symptoms between the pre- and post-surgery assessments were compared between the groups. RESULTS: Patients were followed up to three years and asked to fill out the same questionnaire 16.5±7 (6-36) months in study group and 14.6±6.3 (10-36) months in control group. There were no significant differences between pre- and post-operative prevalence of heartburn, regurtation, chest pain, dysphasia, belching, proton pump inhibitor consumption and between two groups. When patients were divided according to the time following surgery (postoperative period shorter than 12 months and ≤12 months) no difference was observed for the same parameters in both groups. However, epigastric pain and vomiting were significantly decreased in postoperative period in the study group (p=0.001) CONCLUSION: Different than the previous limited data, no change has been observed on the symptoms of GERD following cholecystectomy. Decrease in symptoms of epigastric pain and vomiting in the postoperative period was remarkable. Results of The Study
AGA Abstracts
S-628
using 24 hr esophageal impedance pH monitoring. Methods: 39 patients (29 F, age 47 ±13 yrs) with and without globus symptom who were suspected of GERD underwent 24 hr pHimpedance monitoring following esophageal manometry during off therapy. All patients had a negative upper endoscopy before the study. The present of typical reflux symptoms, upper gastrointestinal symptoms and extraesophageal symptoms were evaluated using a symptom questionnaire. Each acid or non-acid reflux event was analyzed visually for temporal relationship with swallows, gas/liquid composition of the refluxate, proximal extent and bolus contact time. Reflux events during meal ingestion were excluded. Acid refluxes defined as typical impedance changes associated with pH fell below 4 for more than 4 seconds . Nonacid refluxes were defined as the impedance changes associated with pH remaining more than 4. Results: 19, 7, and 13 patients had reflux-like dyspepsia, typical reflux and chronic idiopathic ENT problems as their main symptoms, respectively. Nineteen patients (48.7%) had globus sensation. 31.6% of patients with globus sensation had positive pH test (% time pH<4 at lower esophagus >4.5%) which was similar to patients without globus sensation (25%) p>0.05. 587 acid reflux episodes and 248 non-acid reflux episodes were identified. The proportion of acid/non-acid reflux number was similar between patients with and without globus sensation (5.4±7.9 vs 2.3±2.1, p>0.05). Non acid reflux episodes in patients with globus sensation had significantly more prolonged bolus contact time compared to patients without globus sensation (18.4±9.0 vs 11.9±6.1 seconds, p =0.03). Furthermore, there were more prevalence of immediate swallowing (within 15 seconds) after these nonreflux episodes in patients with globus sensation than patients without globus sensation (53.8±31.4 % vs 30±21.3%, p=0.01). Bolus contact time during acid reflux episodes, immediate swallowing rate after acid reflux episodes, proximal acid and non-acid reflux extension, proportion of liquid/mixed liquid-gas refluxate were similar between patients with and without globus sensation (p>0.05). Conclusions: Non-acid reflux episodes occurred in similar proportion between suspected NERD patients with and without globus sensation. However, the non-acid reflux episodes in patients with globus sensation had longer bolus contact time and induced more swallowing response. This study suggests the possible role of nonacid reflux in the pathogenesis of globus sensation in NERD patients with esophageal or extraesophageal symptoms.
Mo1689 The Effects of Gas Reflux on the Perception of Proximal Reflux in Patients With Non-Erosive Reflux Disease (NERD) Who Have a Positive Symptom Index While on Proton Pump Inhibitor Therapy Noriyuki Kawami, Katsuhiko Iwakiri, Hirohito Sano, Yuriko Tanaka, Mariko Umezawa, Seiji Futagami, Yoshio Hoshihara, Choitsu Sakamoto Background: We have reported that the proximal extent of refluxate is an important factor in determining the perception of reflux in NERD patients who have a positive symptom index (SI) on double-dose PPI therapy, irrespective of the acidity of the refluxate and the duration of proximal reflux episodes (Digestion 2010). The effect of gas reflux however, as a determinant of the perception of reflux, is not clear. Methods: 11 NERD patients with persistent symptoms, despite double-dose PPI therapy, were included in this study. All patients had a positive SI, which was determined by ambulatory 24-hour combined impedance-pH monitoring. Reflux episodes were identified and classified as acid, weakly acidic or weakly alkaline reflux and were considered symptomatic if patients recorded a symptom within 5 min. after a reflux episode. A proximal reflux episode, which reached 15-17cm above the LES, was classified as liquid reflux or mixed reflux. Furthermore, with regard to mixed proximal reflux episodes, the proportion of symptomatic reflux episodes was evaluated at either 5-9cm or 15-17 cm above the LES where the gas reached. Results: In the 11 patients with a positive SI, 914 liquid-containing reflux episodes were recorded. 61 (6.7%) reflux episodes were symptomatic reflux episodes but most (88.5%) symptomatic reflux episodes were weakly acidic reflux. The proportion of symptomatic reflux episodes at 5cm, 7cm, 9cm, 15cm and 17cm above the proximal margin of the LES was 1.7% (3/177), 3.8% (7/186), 6.7% (14/208), 13.6% (12/88) and 10.6% (25/255), respectively. Proximal reflux is significantly more likely to be associated with reflux symptoms, irrespective of the acidity of the refluxate or the duration of the proximal reflux episodes. Amongst the 914 liquidcontaining reflux episodes, 345 (38.0%) were proximal reflux, 206 (59.7%) were liquidonly reflux and 139 (40.3%) were mixed (gas-liquid) reflux. There was no difference in the proportion of symptomatic proximal reflux episodes between liquid-only (13.1%) and mixed (12.1%) reflux episodes. The proportion of symptomatic mixed proximal reflux episodes, in which gas reached 5-9cm above the LES, was 10.0% and 10.6% where gas reached 1517cm above the LES. There was no difference in the proportion of symptomatic reflux episodes between the two. Conclusions: In NERD patients, who have a positive SI on doubledose PPI therapy, there was no effect of gas reflux on the perception of proximal reflux. Mo1690
Mo1688
Notch Signaling is Critical for Gastric Epithelial Cell Homeostasis, Regulating Proliferation, Gastric Antral Stem Cell Marker Expression and Cell Lineage Determination Elise Demitrack, Kelli L. VanDussen, Linda C. Samuelson
The Effect of Cholecystectomy on Gastroesophageal Reflux Symptoms: A Prospective Controlled Study Rukiye Vardar, Suleyman Karakose, Tahsin Tekeli, Sinan Ersin, Serhat Bor
BACKGROUND: Although Notch signaling is known to be a critical regulator of cellular proliferation and cell lineage determination in intestine and other tissues, its role in gastric tissue homeostasis has not been reported. Therefore, the goal of this study was to investigate a potential role for Notch signaling in regulation of antral stem cells, epithelial cell proliferation and lineage commitment in the stomach. METHODS: C57BL/6 mice were treated with vehicle (DMSO) or the gamma-secretase inhibitor (GSI) DBZ (30 μmol/kg daily for 5 days) to globally block Notch signaling, and stomach was collected on the sixth day for histological and gene expression analyses. Gastric tissue was analyzed for markers of mature epithelial cell lineages, including surface mucous (Muc5AC), parietal (H+, K+-ATPase), chief (intrinsic factor), endocrine (chromogranin A and gastrin), and glandular mucous (GSII lectin) cells. Expression of the gastric antral stem cell marker Lgr5 was analyzed by quantitative realtime PCR (qPCR). Apoptosis was detected by caspase-3 staining. Proliferation was measured in tissue sections by morphometric analysis of Ki67 staining and In Vitro by measuring growth of human gastric cancer cell lines AGS and MKN45 after treatment with the GSI DAPT (10 μM). RESULTS: In the gastric corpus, surface mucous, parietal, and endocrine cell lineages were similar in DBZ-treated and vehicle-treated mice. In the gastric antrum, however, DBZ treatment induced an apparent cell fate change, as the normally corpusspecific chief cell marker intrinsic factor was activated in cells in the base of the antral glands, resulting in cells that co-express GSII and intrinsic factor similar to transition cells in the gastric corpus. In response to DBZ treatment, cellular proliferation (cell number per nm2) in both the gastric corpus (0.4 ± 0.05 [vehicle] vs. 0.1 ± 0.05 [DBZ]) and antrum (1.7 ± 0.2 [vehicle] vs. 0.9 ± 0.2 [DBZ]) was significantly reduced. The importance of Notch for gastric cell proliferation was also shown by reduced growth of DAPT-treated AGS and MKN45 cells. Reduced proliferation with GSI treatment suggested that Notch signaling regulates gastric stem or progenitor cells. Accordingly, expression of the antral stem cell marker Lgr5 was markedly reduced in DBZ-treated antral tissue. Furthermore, analysis of cellular apoptosis through activated caspase-3 immunostaining revealed apoptotic epithelial cells in the base of the antral glands where the Lgr5-expressing stem cells reside. CONCLUSION: Notch signaling is crucial to maintain gastric epithelial cell homeostasis by regulating cell proliferation in both corpus and antrum and cell lineage commitment in the antrum. Notch regulation of deep antral gland cell apoptosis and expression of Lgr5 suggests that Notch signaling is required to sustain gastric antral stem cells.
BACKGROUND: It is claimed that gastroesophageal reflux disease (GERD) increases following cholecystectomy. However prospective and comparative studies about the effect of cholecystectomy on gastroesophageal reflux symptoms are very limited and contradictory. We aimed to prospectively compare pre- and postsurgical changes in the prevalence of reflux symptoms on patients with cholecystectomy and inguinal hernia repair surgery as controls. METHODS: We recruited 176 patients scheduled to undergo elective cholecystectomy (study group, n= 126) or inguinal hernia repair (controls, n=50) at two hospitals. Both groups filled out the validated GERD questionnaire 1 to 5 days prior the operation including demographic characteristics, upper gastrointestinal symptoms, drug, smoking and alcohol habits with 54 questions. A hundred and ten patients (78 from cholecystectomy group) who could be reached filled out again same questions 6-36 months following surgery. Changes in symptoms between the pre- and post-surgery assessments were compared between the groups. RESULTS: Patients were followed up to three years and asked to fill out the same questionnaire 16.5±7 (6-36) months in study group and 14.6±6.3 (10-36) months in control group. There were no significant differences between pre- and post-operative prevalence of heartburn, regurtation, chest pain, dysphasia, belching, proton pump inhibitor consumption and between two groups. When patients were divided according to the time following surgery (postoperative period shorter than 12 months and ≤12 months) no difference was observed for the same parameters in both groups. However, epigastric pain and vomiting were significantly decreased in postoperative period in the study group (p=0.001) CONCLUSION: Different than the previous limited data, no change has been observed on the symptoms of GERD following cholecystectomy. Decrease in symptoms of epigastric pain and vomiting in the postoperative period was remarkable. Results of The Study
AGA Abstracts
S-628