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993 Ultrasound Imaging Shows Distinct Differences in 3 Subtypes of Achalasia Esophagus Detected by High Resolution Manometry
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swallows to determine luminal cross sectional area (L-CSA) and muscle thickness. Swallowinduced changes in the luminal size and muscle-CSA(marker of longitudinal muscle contraction) were determined. Results: Luminal CSA was largest in type 1 and the muscle thickest in type 3. Longitudinal muscle contraction with swallow was minimal in type 1 and fairly robust in type 2 and 3 achalasia, see table. Conclusion: US images show that 3 subtypes of HRM defined achalasia show distinct differences at baseline and during swallow in luminal size, and longitudinal muscle contraction associated with swallows.
AGA Abstracts
Localization and Function of Fluorescently-Tagged Delta Opioid Receptor (DOR) Expressed in Enteric Neurons of Knockin Mice Daniel P. Poole, Juan C. Pelayo, Gregory Scherrer, Allan I. Basbaum, Brigitte L. Kieffer, Nigel W. Bunnett Endogenous opioids and opiate drugs have potent effects on intestinal function through activation of μ, δ and κ opioid receptors. Although the role of the μ receptor in these effects and its distribution within the gut wall has been extensively studied, little is known about the expression and function of the δ opioid receptor (DOR) in the intestine. Since the specificity of available DOR antibodies has been questioned (Cell 137:1-12, 2009), we have used an alternative, genetic strategy to determine the distribution and function of DOR in the enteric nervous system (ENS). Methods and Results. Mice in which enhanced GFP (eGFP) was knocked into the opioid delta receptor gene Oprd1 were studied. Western blotting for GFP revealed a protein of ~80kDa in all regions of the gut, consistent with the expected size of DOReGFP. DOReGFP was localized to myenteric and submucosal ganglia and nerve fibers within the muscularis externa and crypts by immunofluorescence, but not in enterocytes, smooth muscle and ICC. Although DOReGFP-positive neurons were rarely observed in submucosal ganglia, DOReGFP was expressed by ~50% of all PGP9.5-immunoreactive (IR) myenteric neurons throughout the intestine. DOReGFP was detected in both ChAT- and NOS-IR neurons of the duodenum (41%, 44%, respectively) and ileum (44%, 53%). DOReGFP also colocalized with ChAT in the cecum (30%), and proximal (9%) and distal colon (20%), but most DOReGFP-positive neurons in the large intestine coexpressed NOS-IR (66%, 96%, 65%, respectively). DOReGFP was not coexpressed with NFM in any region. DOReGFP function was investigated by examining agonist-stimulated trafficking of the receptor in myenteric wholemounts. In unstimulated preparations, DOReGFP was detected at the plasma membrane of the soma and neurites. The DOR agonists SNC80 (10, 100 nM) and met-enkephalin (100 nM) induced receptor clustering within 10 min and receptor trafficking to endosomes after 30 min. After 120-240 min, DOReGFP was in lysosomes, identified by LAMP1-IR. Equivalent results were obtained by live imaging of cultured neurons, and after administration of SNC80 to intact mice. SNC80 (100 nM) stimulated contraction of the isolated distal colon, confirming function. Conclusion. By using a novel approach for specific detection, we found that DOR is similarly distributed in cholinergic excitatory neurons and NOS containing inhibitory motor or interneurons in the small intestine, and that DOR is mostly confined to NOS-positive neurons of the large intestine. Activation induces DOR endocytosis and trafficking to lysosomes, where degradation will down-regulate opioid signaling. Supported by DK399857, NHMRC454858. 967 The CB1 Receptor Antagonist Rimonabant Suppresses Gastric Interdigestive Motility and Hunger Pangs in Healthy Volunteers Sebastien Kindt, Rita Vos, Emidio Scarpellini, Pieter Janssen, Pieter Vanden Berghe, Jan F. Tack
994 Rapid Propagation or Vigorous Contraction: What Defines Esophageal Spasm in High Resolution Esophageal Pressure Topography (HREPT)? Daniel Luger, Peter J. Kahrilas, Neena Malik, Monika A. Kwiatek, Eric Leslie, John E. Pandolfino
Prolonged intake of the the cannabinoid-1 (CB1) receptor antagonist rimonabant results in weight loss, presumably by acting on the central nervous system. However, CB1 receptors are also involved in the control of gastrointestinal motility, and peripheral actions of rimonabant have been implicated in its anti-obesity effect. We identified gastric phase 3 in the interdigestive state as the hunger correlate in the gastrointestinal tract. Our aim was to study the role of CB1 receptors in the control of antroduodenal motility and hunger pangs in man. Methods: Placebo or rimonabant 20 mg were administered orally 20 minutes after the passage of a phase 3 in 9 healthy volunteers (5 women, age 31±2 years, BMI 22.5±0.8 kg/m2) undergoing antroduodenal manometry on 2 occasions, at least 1 week apart, in a double blind cross-over trial. Subjects recorded hunger scores every 10 minutes by 100 mm visual analogue scores. Motility indices from the stomach and small intestine were calculated as the area between signal and baseline normalized over time. Total number of phase 3, time to phase 3 and the number of phase 3 originating from the stomach and duodenum were identified. Student's t-test and Chi-square were applied. Results: In basal conditions mean hunger scores were significantly higher during phase 3 vs. phase 2 (59±6 vs. 38±4 mm, p<0.01) and a gastric origin of phase 3 was identified in 65%. Hunger scores were comparable between phase 2 and 3 originating from the small intestine. Phasic gastric motility was significantly reduced by rimonabant (1.8±0.5 vs. 4.2±0.7 mmHg*min, p<0.05), as were the phase-3 associated hunger pangs (44±8 vs. 63±9 mm, p<0.05). Although after rimonabant, the first phase 3 occurred non-significantly earlier than in placebo (67±8 vs 97±10 min, p=0.07) none (0/9) of the phases 3 had a gastric origin (p<0.05, 4/8 after placebo). Conclusion: Gastric, not small intestinal, phase 3 is associated with hunger pangs. Gastric phase 3 activity and hunger scores are reduced by rimonabant. These actions of the CB1 receptor antagonist rimonabant on the gastrointestinal tract are potentially relevant for the control of appetite and food intake.
BACKGROUND: While the diagnostic criteria of achalasia (absent peristalsis and impaired LES relaxation) are widely agreed upon, those for diffuse esophageal spasm (DES) are less clear. With conventional manometry the most accepted criterion for DES is of simultaneous contractions with at least 20% of test swallows; it is unknown if this criterion applies to HREPT. AIM: To analyze a large series of clinical HREPT studies for different potential phenotypes of spasm (rapid propagation, abnormally vigorous contractions), classify them with current HREPT analytic paradigms, and ascertain their relative prevalence and symptom profiles. METHODS: HREPT studies of 75 control subjects were analyzed to determine 99th percentile upper limits for the contractile front velocity (CFV) and the distal contractile integral (DCI) of their two most abnormal swallows. 2000 consecutive clinical HREPT studies were then reviewed to identify all patients exceeding either of these limits. Type II achalasia was defined by impaired LES relaxation and panesophageal pressurization (>30 mmHg) with ≥20% of swallows; spastic achalasia by impaired LES relaxation and ≥20% swallows with CFV> 99th percentile of normal; DES by normal LES relaxation and ≥20% swallows with CFV> 99th percentile of normal; and spastic nutcracker as normal LES relaxation, normal propagation, and DCI > 99th percentile of normal. RESULTS: The 99th percentile of normal for CFV was 10 cm/s and for DCI 10,000 cm-s-cm. The most common cause of simultaneous esophageal pressurization was type II achalasia (n=171, 8.6% of series). Rapid CFV (mean 35 cm/s) was also seen in 17 (0.9%) patients with spastic achalasia and 2 (0.1%) with DES (mean 37 cm/s). Abnormally vigorous contractions were seen in 32 (1.6%) patients with spastic nutcracker (mean CFV 4.7 cm/s, mean DCI 21,441, maximal peristaltic amplitude/duration 389 mmHg/13 s) and 3 with spastic achalasia (mean DCI 22,120). Both DES patients, 94% of spastic nutcracker patients and 100% of spastic achalasia patients complained of dysphagia and/or chest pain consistent with a major motor disorder. CONCLUSIONS: 1) The only homogeneous non-achalasia major motor disorder in this 2000 patient series, with a prevalence 14% that of achalasia, was spastic nutcracker characterized by normal propagation velocity and repetitive, high amplitude, prolonged contractions. 2) DES, defined by normal LES relaxation and rapidly propagated contractions in conventional manometry, is largely, if not entirely, misdiagnosed achalasia with either panesophageal pressurization or distal spasm.
993 Ultrasound Imaging Shows Distinct Differences in 3 Subtypes of Achalasia Esophagus Detected by High Resolution Manometry Su Jin Hong, Valmik Bhargava, Debbie J. den Boer, Ravinder K. Mittal Background: Achalasia can be divided into 3 distinct types, based on esophageal pressure profile recorded by high-resolution manometry (HRM). Treatment outcome appears to justify the HRM classification. Aims: Goal of our study was to determine if there were differences in the esophageal muscle and luminal area in 3 types of achalasia. Methods: Studies were conducted in 13 patients with manometrically confirmed achalasia esophagus. Simultaneous HRM and high frequency ultrasound images (HFIUS) were recorded during 8 standardized swallows in each subject. HRM determined the type of achalasia based on the swallowinduced pressure changes in the esophagus; type 1, no pressure or simultaneous pressure waves of < 30mmHg, Type 2; simultaneous pressure waves of > 30mmHg, Type 3; contractions with simultaneous onset but sequential ending. US images were analyzed between
AGA Abstracts
995 C-KIT Gene Polymorphism in Achalasia Yesim Ozen Alahdab, Fatih Eren, Feyza Gunduz, Alla E. Kedrah, Yusuf Yilmaz, Ozlen Atug, Nese Imeryuz, Adnan Giral, Erol Avsar, Cem Kalayci Introduction: The number of Cajal cells at the lower esophageal sphincter has been reported to be decreased in achalasia. We hypothesized that the genetic variants in the c-kit gene, which is essential for development and survival of Cajal cells, may be associated with
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swallows to determine luminal cross sectional area (L-CSA) and muscle thickness. Swallowinduced changes in the luminal size and muscle-CSA(marker of longitudinal muscle contraction) were determined. Results: Luminal CSA was largest in type 1 and the muscle thickest in type 3. Longitudinal muscle contraction with swallow was minimal in type 1 and fairly robust in type 2 and 3 achalasia, see table. Conclusion: US images show that 3 subtypes of HRM defined achalasia show distinct differences at baseline and during swallow in luminal size, and longitudinal muscle contraction associated with swallows.
AGA Abstracts
Localization and Function of Fluorescently-Tagged Delta Opioid Receptor (DOR) Expressed in Enteric Neurons of Knockin Mice Daniel P. Poole, Juan C. Pelayo, Gregory Scherrer, Allan I. Basbaum, Brigitte L. Kieffer, Nigel W. Bunnett Endogenous opioids and opiate drugs have potent effects on intestinal function through activation of μ, δ and κ opioid receptors. Although the role of the μ receptor in these effects and its distribution within the gut wall has been extensively studied, little is known about the expression and function of the δ opioid receptor (DOR) in the intestine. Since the specificity of available DOR antibodies has been questioned (Cell 137:1-12, 2009), we have used an alternative, genetic strategy to determine the distribution and function of DOR in the enteric nervous system (ENS). Methods and Results. Mice in which enhanced GFP (eGFP) was knocked into the opioid delta receptor gene Oprd1 were studied. Western blotting for GFP revealed a protein of ~80kDa in all regions of the gut, consistent with the expected size of DOReGFP. DOReGFP was localized to myenteric and submucosal ganglia and nerve fibers within the muscularis externa and crypts by immunofluorescence, but not in enterocytes, smooth muscle and ICC. Although DOReGFP-positive neurons were rarely observed in submucosal ganglia, DOReGFP was expressed by ~50% of all PGP9.5-immunoreactive (IR) myenteric neurons throughout the intestine. DOReGFP was detected in both ChAT- and NOS-IR neurons of the duodenum (41%, 44%, respectively) and ileum (44%, 53%). DOReGFP also colocalized with ChAT in the cecum (30%), and proximal (9%) and distal colon (20%), but most DOReGFP-positive neurons in the large intestine coexpressed NOS-IR (66%, 96%, 65%, respectively). DOReGFP was not coexpressed with NFM in any region. DOReGFP function was investigated by examining agonist-stimulated trafficking of the receptor in myenteric wholemounts. In unstimulated preparations, DOReGFP was detected at the plasma membrane of the soma and neurites. The DOR agonists SNC80 (10, 100 nM) and met-enkephalin (100 nM) induced receptor clustering within 10 min and receptor trafficking to endosomes after 30 min. After 120-240 min, DOReGFP was in lysosomes, identified by LAMP1-IR. Equivalent results were obtained by live imaging of cultured neurons, and after administration of SNC80 to intact mice. SNC80 (100 nM) stimulated contraction of the isolated distal colon, confirming function. Conclusion. By using a novel approach for specific detection, we found that DOR is similarly distributed in cholinergic excitatory neurons and NOS containing inhibitory motor or interneurons in the small intestine, and that DOR is mostly confined to NOS-positive neurons of the large intestine. Activation induces DOR endocytosis and trafficking to lysosomes, where degradation will down-regulate opioid signaling. Supported by DK399857, NHMRC454858. 967 The CB1 Receptor Antagonist Rimonabant Suppresses Gastric Interdigestive Motility and Hunger Pangs in Healthy Volunteers Sebastien Kindt, Rita Vos, Emidio Scarpellini, Pieter Janssen, Pieter Vanden Berghe, Jan F. Tack
994 Rapid Propagation or Vigorous Contraction: What Defines Esophageal Spasm in High Resolution Esophageal Pressure Topography (HREPT)? Daniel Luger, Peter J. Kahrilas, Neena Malik, Monika A. Kwiatek, Eric Leslie, John E. Pandolfino
Prolonged intake of the the cannabinoid-1 (CB1) receptor antagonist rimonabant results in weight loss, presumably by acting on the central nervous system. However, CB1 receptors are also involved in the control of gastrointestinal motility, and peripheral actions of rimonabant have been implicated in its anti-obesity effect. We identified gastric phase 3 in the interdigestive state as the hunger correlate in the gastrointestinal tract. Our aim was to study the role of CB1 receptors in the control of antroduodenal motility and hunger pangs in man. Methods: Placebo or rimonabant 20 mg were administered orally 20 minutes after the passage of a phase 3 in 9 healthy volunteers (5 women, age 31±2 years, BMI 22.5±0.8 kg/m2) undergoing antroduodenal manometry on 2 occasions, at least 1 week apart, in a double blind cross-over trial. Subjects recorded hunger scores every 10 minutes by 100 mm visual analogue scores. Motility indices from the stomach and small intestine were calculated as the area between signal and baseline normalized over time. Total number of phase 3, time to phase 3 and the number of phase 3 originating from the stomach and duodenum were identified. Student's t-test and Chi-square were applied. Results: In basal conditions mean hunger scores were significantly higher during phase 3 vs. phase 2 (59±6 vs. 38±4 mm, p<0.01) and a gastric origin of phase 3 was identified in 65%. Hunger scores were comparable between phase 2 and 3 originating from the small intestine. Phasic gastric motility was significantly reduced by rimonabant (1.8±0.5 vs. 4.2±0.7 mmHg*min, p<0.05), as were the phase-3 associated hunger pangs (44±8 vs. 63±9 mm, p<0.05). Although after rimonabant, the first phase 3 occurred non-significantly earlier than in placebo (67±8 vs 97±10 min, p=0.07) none (0/9) of the phases 3 had a gastric origin (p<0.05, 4/8 after placebo). Conclusion: Gastric, not small intestinal, phase 3 is associated with hunger pangs. Gastric phase 3 activity and hunger scores are reduced by rimonabant. These actions of the CB1 receptor antagonist rimonabant on the gastrointestinal tract are potentially relevant for the control of appetite and food intake.
BACKGROUND: While the diagnostic criteria of achalasia (absent peristalsis and impaired LES relaxation) are widely agreed upon, those for diffuse esophageal spasm (DES) are less clear. With conventional manometry the most accepted criterion for DES is of simultaneous contractions with at least 20% of test swallows; it is unknown if this criterion applies to HREPT. AIM: To analyze a large series of clinical HREPT studies for different potential phenotypes of spasm (rapid propagation, abnormally vigorous contractions), classify them with current HREPT analytic paradigms, and ascertain their relative prevalence and symptom profiles. METHODS: HREPT studies of 75 control subjects were analyzed to determine 99th percentile upper limits for the contractile front velocity (CFV) and the distal contractile integral (DCI) of their two most abnormal swallows. 2000 consecutive clinical HREPT studies were then reviewed to identify all patients exceeding either of these limits. Type II achalasia was defined by impaired LES relaxation and panesophageal pressurization (>30 mmHg) with ≥20% of swallows; spastic achalasia by impaired LES relaxation and ≥20% swallows with CFV> 99th percentile of normal; DES by normal LES relaxation and ≥20% swallows with CFV> 99th percentile of normal; and spastic nutcracker as normal LES relaxation, normal propagation, and DCI > 99th percentile of normal. RESULTS: The 99th percentile of normal for CFV was 10 cm/s and for DCI 10,000 cm-s-cm. The most common cause of simultaneous esophageal pressurization was type II achalasia (n=171, 8.6% of series). Rapid CFV (mean 35 cm/s) was also seen in 17 (0.9%) patients with spastic achalasia and 2 (0.1%) with DES (mean 37 cm/s). Abnormally vigorous contractions were seen in 32 (1.6%) patients with spastic nutcracker (mean CFV 4.7 cm/s, mean DCI 21,441, maximal peristaltic amplitude/duration 389 mmHg/13 s) and 3 with spastic achalasia (mean DCI 22,120). Both DES patients, 94% of spastic nutcracker patients and 100% of spastic achalasia patients complained of dysphagia and/or chest pain consistent with a major motor disorder. CONCLUSIONS: 1) The only homogeneous non-achalasia major motor disorder in this 2000 patient series, with a prevalence 14% that of achalasia, was spastic nutcracker characterized by normal propagation velocity and repetitive, high amplitude, prolonged contractions. 2) DES, defined by normal LES relaxation and rapidly propagated contractions in conventional manometry, is largely, if not entirely, misdiagnosed achalasia with either panesophageal pressurization or distal spasm.
993 Ultrasound Imaging Shows Distinct Differences in 3 Subtypes of Achalasia Esophagus Detected by High Resolution Manometry Su Jin Hong, Valmik Bhargava, Debbie J. den Boer, Ravinder K. Mittal Background: Achalasia can be divided into 3 distinct types, based on esophageal pressure profile recorded by high-resolution manometry (HRM). Treatment outcome appears to justify the HRM classification. Aims: Goal of our study was to determine if there were differences in the esophageal muscle and luminal area in 3 types of achalasia. Methods: Studies were conducted in 13 patients with manometrically confirmed achalasia esophagus. Simultaneous HRM and high frequency ultrasound images (HFIUS) were recorded during 8 standardized swallows in each subject. HRM determined the type of achalasia based on the swallowinduced pressure changes in the esophagus; type 1, no pressure or simultaneous pressure waves of < 30mmHg, Type 2; simultaneous pressure waves of > 30mmHg, Type 3; contractions with simultaneous onset but sequential ending. US images were analyzed between
AGA Abstracts
995 C-KIT Gene Polymorphism in Achalasia Yesim Ozen Alahdab, Fatih Eren, Feyza Gunduz, Alla E. Kedrah, Yusuf Yilmaz, Ozlen Atug, Nese Imeryuz, Adnan Giral, Erol Avsar, Cem Kalayci Introduction: The number of Cajal cells at the lower esophageal sphincter has been reported to be decreased in achalasia. We hypothesized that the genetic variants in the c-kit gene, which is essential for development and survival of Cajal cells, may be associated with
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