Abstracts of the 19th American Neurogastroenterology and Motility Society Annual Scientific Meeting August 13–15, 2021 Boston, Massachusetts, USA

Abstracts of the 19th American Neurogastroenterology and Motility Society Annual Scientific Meeting August 13– 15, 2021 Boston, Massachusetts, USAs of the 19th American Neurogastroenterology and Motility Society Annual Scientific Meeting August 13– 15, 2021 Boston, Massachusetts, USA

tious, metabolic, and immune-mediated defects that alter structure and function of the enteric nervous system, interstitial cells of Cajal and intestinal smooth muscle (among other cell types). The role of micronutrients in development and function of cells that control bowel motility is largely unexplored. A few papers show vitamin A deficiency or excess alters enteric nervous system development in mouse and avians at least in part via regulation of RET or PTEN in the enteric nervous system. Vitamin A is a precursor for retinoic acid, a regulator of gene expression that binds to retinoic acid receptors RAR/RXR to control many aspects of development and postnatal cell function. Retinoic acid signaling affects most cell types and many cells support enteric nervous system development. Prior studies in mutant animals or using chemical regulators of RAR did not unambiguously define which cells required retinoic acid signaling for normal development or evaluate the role of RAR signaling at later stages of development. To address these issues, we took advantage of a dominant negative retinoic acid receptor that is expressed after CRE-mediated DNA recombination in mice. We discovered that cell-autonomous retinoic acid receptor signaling within the enteric nervous system lineage is required to activate RET expression in enteric nervous system precursors as they migrate from neural tube to bowel (consistent with prior data), and also is needed to activate PHOX2B expression in these cells. Early loss (E8.5) of retinoic acid signaling therefore causes complete intestinal aganglionosis similar to the phenotype of Ret −/− and Phox2b −/− mice. Loss of cell-autonomous retinoic acid receptor signaling at later stages causes patterning defects and hypoganglionosis in the colon, loss of submucosal neurons, and changes in neuronal subtype identity. RNA sequencing from enteric nervous system cells at E11.5 and E13.5 demonstrated ~1000 genes regulated by retinoic acid at each age. Remarkably, different gene regulatory networks are activated by retinoid signaling at E11.5 and E13.5. Collectively, these data suggest that vitamin A deficiency (a very common global problem) and excess vitamin A can alter bowel motility in many ways and could contribute to the risk of Background: Corticolimbic brain circuits demonstrate abnormal activity in patients with stress-induced visceral pain disorders, such as irritable bowel syndrome (IBS), characterized by colonic hypersensitivity. The prefrontal cortex (PFC) has been shown to participate in both pain and stress modulation. We have previously found that the pathway from the central amygdala to the bed nucleus of the stria terminalis (BNST) modulates colonic sensitivity in the rat. The BNST also receives signals from the PFC, but the role of the PFC in the modulation of stress-induced colonic nociception is unknown. The hypothesis for this study was that activation of PFC-BNST pathway could induce colonic hypersensitivity.

Methods:
The role of PFC-BNST signaling was tested by infecting the PFC with viral vectors to express channelrhodopsin (ChR) or halorhodopsin (HR) and implanting fiber optic cannula at the BNST in male Fischer 344 rats (n = 4/group). A different cohort of rats had a single micropellet (30 µg) of the stress hormone, corticosterone (CORT) or cholesterol (CHOL) control implanted in the PFC (n = 8/group) to test the effect of stress on colonic sensitivity. In freely moving rats, colonic sensitivity was assessed as the number of abdominal contractions to graded, isobaric colorectal distension (20-60 mmHg, 10 min). In rats with opsins, colonic sensitivity was assessed with and without laser stimulation after 10 weeks. In rats with micropellets, colonic sensitivity was measured after 8 days at the peak diffusion of the micropellet. Results were analyzed with a repeated measure two-way ANOVA with Bonferroni's post-hoc analysis (mean ± standard deviation).
To demonstrate the role of stress on PFC signaling, rats with CORT implanted in the PFC developed colonic hypersensitivity compared to CHOL-implanted controls (60 mmHg: 37.9 ± 4.6 vs. 24.3 ± 2.7, p<0.01).
Conclusions: Both optogenetic and stress-induced signaling from the PFC to the BNST induced colonic hypersensitivity. These results support the role of the PFC-BNST pathway as part of a corticolimbic circuit that modulates visceral sensation in response to stress.
Modulation of the PFC-BNST pathway could represent a valid target for novel therapies to treat disorders such as IBS.

| Enteric glia sensitize nociceptor TRPV1 during acute inflammation through connexin-4 3 -dependent pros t aglandin-E2 release
Symptom of dysphagia was more prevalent (p = 0.03) in Group 2, but reflux and regurgitation symptoms were not different. Nervous system disorders were less prevalent in Group 1 (35% vs. 52%, p = 0.03), but prevalence of musculoskeletal/connective tissue, mood, and endocrine disorders was not different. There was no difference in frequency of common medications. On HRM for Group 1, percent of failed contractions was associated with bolus clearance (r = −0.2, p = 0.03) and bolus escape (r = 0.4, p = 0.0001); this association was not significant in Group 2. No correlation was found between motility findings on HRM and barium studies in either group. Percent of weak contractions on HRM and barium tablet delay were associated (p = 0.04) in Group 1, but not in Group 2. Dysphagia was associated with no delay in barium in Group 2 (p = 0.04), with no association in Group 1. Dysphagia-but not reflux, regurgitation, or opioid usewas associated with an abnormal IRP (p = 0.005) when all patients were combined. In all groups, mean LES pressure was not associated with an upper endoscopy finding of esophagitis or hiatal hernia, dysphagia, reflux, or regurgitation.
Conclusions: Most features studied did not differ between Groups 1 and 2. A CCv4.0 IEM diagnosis is associated with worse esophageal function (reduced bolus clearance, increased bolus escape, and barium tablet delay). Symptom of dysphagia is not associated with worse motility, suggesting that dysphagia is not primarily dependent on bolus transit. Three Tam-treated mice that died suddenly and displayed greatly enlarged stomach with food residue at necropsy were also considered to have DGE. In all, 9 of 11 (82%) of Tam-treated ♀ Kit creERT2/+ ;Sdhc fl/ ⁻ mice developed DGE between 0.6 and 7.7 weeks post-DM, whereas only 2 of 8 (25%) ♀ Veh-treated Kit creERT2/+ ;Sdhc fl/ ⁻ mice and 12 of with neurons in neurocircuits that control gastrointestinal functions, but whether neuron-glia communication is heterogeneous in different regions of the intestine remains unknown. We tested whether myenteric glia display regional and functional heterogeneity in two functionally distinct regions: the duodenum and colon. We used in situ calcium (Ca 2+ ) imaging in whole-mount preparations of myenteric plexus from transgenic mice expressing genetically encoded calcium sensors in enteric glia and used immunohistochemistry to assess glial receptor patterns. Comparable proportions of glia responded to ADP (100 µM) and CCK (100 nM) in the duodenum (64% and 47%, respectively) and colon (91% and 79%, respectively), but more glia responded to ADP in the colon than in the duodenum. Ca 2+ responses to both neuromodulators were higher in the colon than duodenum (ADP: p < 0.00010 colon vs duodenum; CCK: p = 0.0005 colon vs duodenum,), although CCK resulted in a greater response in the duodenum than in the colon when compared to peak ADP responses (p = 0.0167 for ADP vs CCK in the duodenum and p < 0.0001 for ADP vs CCK in the colon). The changes in the percentage of glia responding to ADP and CCK upon treatment with TTX (300 nM) or FA (5 mM) in the myenteric plexus of duodenum and colon (−70% for ADP in FA-treated duodenum; −27% and −25% for ADP in TTX-or FA-treated colon and −58% for CCK in FA-treated colon vs untreated tissues) and related glial Ca 2+ responses (−36% and −70% for ADP in TTX-or FA-treated duodenum and +139% for CCK in TTX-treated duodenum; −67% and +27% for ADP in TTXor FA-treated colon and +23% and +60% for CCK in TTX-or FAtreated colon vs untreated tissues) suggest that glial responses to ADP require intercellular signaling with neurons in the duodenum, and that glial responses to CCK involve intercellular signaling with neurons in the duodenum. Our results also show that CCKBR are mainly expressed by neurons in myenteric ganglia of the duodenum (Pearson correlation coefficient for peripherin and GFAP = 0.5095 and 0.1486, respectively) and by myenteric glia in the colon (Pearson correlation coefficient for GFAP and peripherin = 0.8191 and 0.334, respectively). Similar and higher expression of P2Y1Rs is found in the myenteric neurons of both regions (Pearson correlation coefficient for peripherin = 0.6225 and 0.6530, and for GFAP = 0.2291 and 0.2476 in the duodenum and colon, respectively). Our findings support the conclusion that myenteric glia exhibit regional heterogeneity that could contribute to region-specific mechanisms that regulate digestive functions. Glial heterogeneity adds an unexpected layer of complexity in peripheral neurocircuits in the adult ENS.

| RE T signaling in enteroen docrine cells regulates gut motilit y in a sexdependent manner
A. Shepherd 1,* , L. Feinstein 2,* , S. Sabel 2,* , D. Rastelli 1 , E. motility. To test this hypothesis, we examined RET expression in the postnatal gut and identified two populations of RET-expressing cells involved in peristalsis, NOS1 + /VIP + inhibitory motor neurons in the ENS and enteroendocrine cells (EECs) in the epithelium. We generated mice lacking RET in each of these populations and found that RET depletion in EECs, but not neurons, slowed GI transit. This motility defect was observed in males but not females. Pharmacologic inhibition of RET kinase in wildtype mice phenocopied this defect.
EECs are a diverse group of cells that detect information from the gut lumen. The majority of RET + EECs were either enterochromaffin cells, which release serotonin (5-HT), or L-cells, which release peptide YY (PYY). Both 5-HT and PYY can signal to enteric neurons to alter GI motility. We examined the effects of RET disruption on these EEC-derived signals and found that diminished RET signaling led to exaggerated release of PYY in a nutrient-dependent manner both in vitro and in vivo. Pharmacologic blockade of the PYY receptor rescued the motility defect in mice lacking RET in EECs. Together, these findings indicate that RET signaling normally limits nutrientdependent PYY release in L-cells and that this activity is essential for normal GI motility in males. This work highlights a novel mechanism that could underlie chronic dysmotility in post-operative HD patients and a new therapeutic target for modulating motility in functional GI disorders.
benefits of adding gastroparesis diets or drugs like neuromodulators to improve prokinetic responses are unproved. We hypothesized: (i) prokinetics alone have limited benefit in suspected gastroparesis, (ii) symptoms improve more if prokinetics are combined with diet or neuromodulators, and (iii) gastric emptying has modest impact on responses.
Methods: Therapy changes were recommended based on concurrent wireless motility capsule (WMC) and gastric scintigraphy tests for 138 patients with suspected gastroparesis. GCSI (0 = none, 5 = very severe) scores from baseline to 6-month followup were compared relating recommendations to take prokinetics alone or with diets or neuromodulators (tricyclics, mirtazapine, gabapentin, others). Multivariate models assessed WMC gastric emptying time (GET) impact on responses. | 9 of 57 ABSTRACT persist beyond ED remission or are a manifestation of ongoing ED pathology. We sought to determine the relationship between GI disorders and ED remission.

Methods:
We constructed a retrospective review of 250 patients with an ED and GI encounter at a tertiary care center between 2010-2020. We determined diagnostic details, classifying GI diagnoses as "structural" or "functional" and EDs by DSM-IV-TR as anorexia nervosa (AN), bulimia nervosa (BN), or eating disorder not otherwise specified (EDNOS). We determined the temporal relationship between the ED diagnosis and GI consult and assessed ED remission.
We used multivariable regression to determine factors associated with functional GI diagnoses and the relationship to ED remission.

Conclusions:
Over half of patients with EDs and GI symptoms were found to have a functional GI disorder. A subset of ED patients seeking GI care are less likely to be in remission and could benefit from ED-specific treatments. Additionally, the high prevalence of functional GI disorders seen in remitted ED patients suggests a role for past EDs in GI symptom pathogenesis. Functional dyspepsia (FD) patients experience upper gastrointestinal (GI) symptoms possibly due to gastric motor or sensory dysfunction. Gastric afference is received by the nucleus tractus solitarii (NTS). We hypothesize that altered NTS connectivity to higher brain regions in FD will be associated with gastric dysmotility during a meal challenge. 15 FD and 14 healthy control (HC) subjects consumed the maximum tolerable amount of a 470 ml high-calorie pudding. Post meal, subjects alternated 3 times between stomach and brain MRI scans (Siemens 3T Skyra). Gastric 4D cine-MRI were collected continuously for 5 min (temporal resolution: 7 s). During brain scans, resting-state functional MRI data were acquired. Timeseries from left NTS (A) were used to generate seed-to-voxel whole-brain functional connectivity maps. Relative to HCs, FD patients demonstrated increased NTS connectivity to anterior medial prefrontal cortex (mPFC), superior frontal gyrus (SFG), and bilateral inferior frontal gyri (IFG) (B). Peristaltic propagation velocity in the antrum was calculated from the segmented gastric data (C). Reduced peristaltic propagation velocity was found in FD (HC = 5.58 ± 1.68 mm/s, FD = 3.76 ± 0.76, p = 0.003), and was negatively correlated to NTS connectivity (D). Our results reveal shifts in NTS functional connectivity from the self-referential processing Default Mode Network to the executive control processing FrontoParietal Control Network in the brain, potentially related to an altered cognitive processing of visceral GI sensations in FD. Furthermore, these altered connections are linked to physical properties of gastric peristalsis. the gastrointestinal tract (GI). While the etiology of IBS remains unclear, stress has been shown to play a significant role in visceral pain.

| A ltered gut af ference-related br ain connec tivit y in func tional dyspepsia is linked to slower gas tric peris t alsis -a multimodal gut-br ain a xis MRI s tudy
Here, we utilize a monoclonal anti-CGRP F(ab') 2 antibody to test the hypothesis that inhibition of peripheral CGRP signaling will reverse colonic hypersensitivity induced by both a chronic psychological stress and early life stress (ELS) in a rodent model.

Methods:
One cohort of adult rats were exposed to repeated water avoidance stress (WAS) (1 h/day for 10 days). Sham WAS-treated rats served as controls. A second cohort was exposed to an odorattachment learning model of unpredictable ELS. Odor-only treated neonates serves as controls. In adulthood colonic sensitivity was quantified using a visceral motor response (VMR), quantified as the number of abdominal contractions, to graded pressures (0, 20, 40, 60 mmHg) of isobaric colorectal distension (CRD). Spinal extracellular signal-regulated kinase (ERK1/2) phosphorylation was assessed via immunohistochemistry. Stressed rats received a single intraperitoneal (i.p.) administration of anti-CGRP F(ab') 2 (30 mg/kg), 24-hr prior to measuring colonic sensitivity.

Summary and conclusions:
Exposure to either a repeated psychological stress in adulthood or unpredictable stress during the neonatal period induces colonic hypersensitivity as well as enhanced evoked spinal ERK1/2 phosphorylation. These stress-induced phenotypes were reversed by inhibition of peripheral CGRP signaling, suggesting further investigation of an anti-CGRP antibody as a novel treatment strategy for IBS-related stress-induced visceral pain.  1.6 [1.5-1.7], p < 0.0001), with significantly more prevalent sensitivities to 6 of 11 food types; Table 1. Follow-up analyses showed elevated number of reported food sensitivities in IBS diarrhea (IBS-D) and mixed (IBS-M) subtypes, but not in IBS with constipation (IBS-C).

P OS TER S E SS I ON
Number of food sensitivities reported by those with IBS correlated modestly with somatization (r = 0.24, p = 0.01) and was not Purpose: The stomach-brain interaction is critical for regulating gastric function. This interaction is better understood in terms of the vago-vagal reflex but remains largely unclear beyond. A prior study suggests that the human brain maintains a slow rhythm coupled to the gastric slow wave [1]. Here, we further hypothesize that the rat brain not only maintains neural copies of gastric rhythms but also encodes their frequency and power fluctuations. To test this hypothesis, we acquired concurrent fMRI and electrogastrogram (EGG) from eight rats and assessed the relationship between the fMRI signal and the frequency and power fluctuations of gastric slow wave.

Results:
With simultaneous recordings of EGG and fMRI, we assessed the relationship between BOLD activity and various features of EGG in rats. First, the dominant frequency of gastric slow waves was identified for every 4-min segment. The coherence at the dominant frequency was then calculated between EGG and fMRI to assess whether fMRI signals were phase-coupled to the gastric slow waves. The result showed that EGG and fMRI activity were coherent at the dominant frequency in various brain regions, covering the somatomotor, emotion-cognitive, reward-modulation, and olfactory-related areas.
We also extracted temporal fluctuations of narrow-band EGG rhythms and tested their relationship with the BOLD activity. The EGG rhythm at five cycles per minute, a hallmark feature of gastric pace-making activity, could linearly explain the BOLD signal at regions, such as the ventromedial thalamic nucleus, insular cortex, and orbital cortex.

Conclusion:
The rat brain is not only synchronized with the gastric slow wave but also encodes the power fluctuation of gastric pacemaking activity via the NTS-insula-somatosensory network.
[ There was no significant difference between two sexes. hpChAT-ir fibers showed no significant difference among plexi and segments.
A large portion of genes in the myenteric cholinergic neurons are involved in coping with defense response to inflammation via TNF signaling pathway. In parallel, electrical stimulation of the celiac branch of the vagus nerve (CBVN, 2 Hz, 0.3 ms, 5 mA) caused a dramatic increase (>60-fold, compared to baseline) in the plasma IL1ra levels immediately and at 30 min post-stimulation periods.
These results revealed for the first time the regional difference in the autonomic cholinergic innervation in 3D structure and provide neuroanatomical and transcriptomic evidence for CAP in the pig colon. The increased plasma IL1ra in response to CBVN stimulation extends the anti-inflammatory effects of vagal neuromodulation and possible activation of CAP in pigs. GI involvement and dysmotility is limited to superficial biopsies. We aim to characterize GI symptoms and dysmotility in relation to degree of Gb3 involvement. We hypothesize that a higher degree of Gb3 involvement is associated with more GI symptoms.
Subjects were grouped as Low (−/+) or High (++/+++) Deposition.  Sensory systems interpret and transduce environmental stimuli into physiologic responses. The GI tract has a highly developed sensory system that is based the physical interaction between luminal contents and the gut wall. Therefore, it is critical that we understand GI mechanosensing. To process mechanical stimuli, the gut requires specialized sensory neurons called intrinsic primary afferent neurons (IPAN) that reside within both submucosal and myenteric plexuses.
While previous studies demonstrated that some IPANs are mechanosensitive, the molecular mechanisms of mechanotransduction in IPANs remain poorly understood.

Methods:
Recent studies from our group show that the gut uses Advillin+ cell as IPANs. We used Avil creERT2/+ ::tdTomato/GCaMP5 f/+ mice to lineage trace and functionally assess the IPANs. We dissociated the small intestine myenteric plexus to study Advillin cells (tdTo-mato+) using whole cell electrophysiology and Ca 2+ imaging with direct membrane displacement by a piezo-electrically driven microprobe.

Results:
In whole-cell patch clamp, we found that 6 of 6 Advillin+ neurons displayed rapidly adapting mechano-currents (peak −316.02 ± 74.08 pA, inactivation time constant τi = 5.06 ± 0.77 ms) induced by direct membrane displacement (up to 7 μm). In Ca 2+ imaging experiment, we found Ca 2+ increase when Advillin+ neurons were subjected to membrane displacement (2 μm, 68%). Forceinduced Ca2+ increases were reversibly inhibited by Piezo channel blockers: gadolinium (Gd3+, 30 μM, n = 4) and D-GsMTx4 (10 μM, n = 6) (∆F/F0: ctrl 1.07 ± 0.53 vs. Gd3+ 0.0005 ± 0.0003 and ctrl D-       Conclusions: EGJ-CI can independently predict pathological GERD. However, the poor correlation between EGJ-CI and esophageal acid exposure indicates that mechanisms other than baseline EGJ barrier function play a role in GERD development. Factors such as age and integrity of peristalsis also contribute. Calculated thresholds for EGJ-CI and total EGJ-CI yield low sensitivity and specificity for the diagnosis of GERD. Larger studies are required to assess the roles of these manometric tools as independent predictors in the pathophysiology of GERD. Prospective studies to further assess safety and symptomatic outcomes in children are greatly needed. 5 4 | Sar s-CoV-2 (COVID -19) prospec tive qualit y control projec t : exploring a patient prof ile relative to scheduling a motilit y labor ator y procedure related to Sar s-CoV-2 an xiet y   and 0.49 respectively). AUCs for the 4 metrics were statistically similar ( Figure 1).

Conclusion:
The four studied impedance metrics were significantly lower in the severe esophagitis/BE group; they all showed modest ability in distinguishing these patients from controls.
Being the most simple to calculate, BLI can help identify these complications of GERD in patients who decline or cannot perform an EGD.

Figure 1
Receiver operating characteristic (ROC) curve  Patient is being considered for steroid therapy after improvement of complicated aspirational pneumonia.  Charts were reviewed for demographics, symptoms, comorbidities, medications, manometric data, and findings on additional studies.

Discussion
Means are presented with standard deviations (mean ± SD).   Background: Gastroesophageal reflux disease (GERD) has been associated with interstitial lung disease (ILD) and poorer pulmonary function, potentially due to gastric refluxate-induced lung damage.

| E arly life f ac tor s in eosinophilic esophagitis: A s ys tematic review an d met aanalysis
Identifying those at risk for reflux-related lung injury may affect management of ILD, but the optimal strategy to assess GERD and esophageal measures most associated with clinical severity remain unclear.
For linear calculations, adjacent measurements before and after 50% empty were used. Spearman's rho was used for correlations. Conclusions: GES T ½ correlates more strongly with retention at 2 and 3 h than at 4 h; this was seen for each of the three t 1/2 methods.

Results
T 1/2 alone may misclassify patients, particularly those with only late phase delayed GE, reducing its diagnostic utility for gastroparesis.  (2) Relate meal eating characteristics to symptoms, gastric emptying (GE), and body weight.

| Subt y pes of gas troparesis (G P) an d func tional dyspepsia (FD) based on gas tric myoelec tric al ac tivit y (G MA ) in response to the water load s atiet y tes t ( WL S T )
K Methods: Patients with symptoms associated with GP were studied.
GP was defined by > 60% meal retained at 2 hrs. and/or > 10% at 4 hrs. by scintigraphy. GMA was recorded with cutaneous electrogastrography with the WLST during which patients ingested water until completely full over a 5-minute period. The % GMA activity in 4 frequency ranges (normal 2.5-3.7 cpm; bradygastria, 1.0-2.5 cpm; tachygastria, 3.7-10.0 cpm; duodenal-respiration, 10-15 cpm) was determined and compared with controls. Symptoms were assessed using a 100 mm visual analog scale. Ingestion of less than 238 ml of water in 5 min was considered abnormal.
Results: 284 patients with GP and 113 patients with FD (symptoms associated with GP but normal emptying) were studied. GP and FD patients ingested similar volumes of water (mean ± SD: 378 ± 218 ml and 402 ± 226 ml; p = 0.15) and reported similar increases in postprandial fullness, nausea, bloating, and abdominal discomfort. 26% of GP and 19% of FD patients ingested < 238 ml water (p = 0.05).
Gastric dysrhythmias were recorded in 66% and 65% of patients with GP and FD, respectively; normal 3 cpm GMA was recorded in 34% and 35% of patients with GP and FD, respectively. Although overall % of gastric dysrhythmias and normal GMA were similar in the two groups, there were differences in the classifications of specific diagnoses (p = 0.02) ( Table 1).    Further work with chemiluminescent testing in patients with upper

| A new antibo dy ass ay may help identif y abnormalities in patient s with the s y mptoms of gas troparesis
GI motility disorders appears warranted. Sensitivity analysis was performed on pts that reported highest (scaled 3-4) Sx scores (Table 2). Pts with high vomiting Sx were younger (median age 42), 75% of pts. reported nausea and anorexia was the main Sx in the improved group. In the group that did worse, main symptom scores involved nausea and abdominal pain.

Conclusion:
Pts seen in an academic motility center had > 40% improvement in 1pt for either upper or lower GI Sx at 3 year follow-up and 20% improved in both upper and lower Sx. Nausea is a predominant feature that could be used as a target to optimize outcomes.
Pts with anorexia predominant symptoms appear to be a high yield target for future symptom score improvement. Based on this assessment, sx tracking could be an important tool to further characterize the best treatment approaches in GI motility pts. was still a trend towards longer acidification time in patients with positive reflux testing in both groups, but this was not statistically significant. Methods: Data from scintigraphic measurements of GE of solids using a standard 320 kcal egg meal (30% fat) were analyzed. Data were previously published for patients on placebo treatment.
Bland-Altman plot was constructed for the intra-subject comparison for GP on placebo.

Results:
The patient cohort consisted of 30 patients (10 DM1, 10 DM2 with one GE measurement each, and 3 DM and 7 idiopathic GP with two GE measurement each 28 days apart). Bland-Altman plot (figure) in GP showed difference (∆) GE T 1/2 similarly distributed (4 weeks apart) across mean GE T 1/2 120-240 min, except for one patient with severe GP. The GE T 1/2 in gastroparesis demonstrated an average 9.4% change relative to mean GE T 1/2 202.4 min with the COV intra 11.1%.

Conclusions: Inter-subject variations (COV inter ) in scintigraphic GE
results in diabetics with GD symptoms were lowest for GE 4 h%.
Within subject measurements of GE T 1/2 (4 weeks apart) in gastroparesis were also reproducible over time, with average change of 9.4% and COV intra 11.1%.       The period-prevalence of constipation, defined as any occurrence between baseline and week 4, was also compared by age group.

| Motilit y in Parkinson's disease: Iis a multidisciplinar y approach the bes t move?
available pertaining to community gastroenterologists (CG) versus academic gastroenterologists (AG) related to PD symptom work-up.
Objectives: (i) Compare GI symptom presentations of PD patients seen by academic versus community gastroenterologists (ii) Assess differences between CG vs. AG related to diagnostic workup of PD patients.
Methods: Retrospective analysis of 32 adult patients with PD who were referred to either a CG or AG. Collected data included demographics, GI presenting symptoms, urological symptoms, and diagnostic testing ordered (endoscopic, radiological, and physiology).
Statistical analyses included chi-square test and independent t-tests.
p-values < 0.05 were considered statistically significant.
Results: 32 subjects were included in the analysis: mean age of 73.6 ± 9.7: Range: 46-88, mean BMI 24.9 ± 8.2. No demographic differences between CC or AC centers were seen. Statistically significant differences were seen between the CC and AC for symptoms of fecal incontinence and for urological symptoms only. Statistically significant differences between the CC and AC for diagnostic testing included: Modified Barium Swallow Studies, EndoFLIP™ Impedance Planimetry, Gastric Emptying Study, Anorectal manometry and biofeedback therapy. Statistically significant mean total of physiological lab tests between AC and CC: 1.9 ± 1.3 AG and .32 ± .568 CG, p-value < .001.
Radiological testing was also statistically significant with mean .80 ± .632 for AG and .36 ± .492 for CG, p-value .042. Total number of diagnostic tests were similar between the groups: Mean 2.8 ± 1.1 AG and 2.7 ± 1.2 CG. Total number of endoscopic evaluations were also similar with mean 1.3 ± .68 for AG and 1.2 ± 1.2 for CG.

Conclusion:
Patients with PD are referred to academic multidisciplinary centers more commonly for symptom presentations of fecal incontinence and urinary issues. AG were more likely to proceed with ordering radiological and physiology tests. This preliminary data will be used to evaluate the benefit to PD patients of a multidisciplinary approach to care including assessing the benefit of increased diagnostic testing to guide targeted therapies to improve patient's QOL.  time ( ± SD) delay for an air-swallow (60.5 ± 39.2 seconds) prior to a hiccup was significantly longer compared to GER (10.3 ± 4.0 seconds, p = 0.001), gastric belches (9.1 ± 5.9 seconds, p = 0.001) and

Discussion and Conclusion:
While the pathophysiology of hiccups is unclear, studies have suggested distension of the proximal esophagus for playing role. Our study, using a novel application of the MII-pH technology, reveals objective data that support a temporal relationship between hiccups and EAEs (including supragastric belches, gastric belches and air swallows). Additional studies are needed to further explain our observations.
97 | S hould all as y mptomatic inf ant s un der the age of 12 months un der going impedance tes ting be assessed for aerophagia? Background: Gastroesophageal reflux (GER) and air swallowing are both common in infants. While the association of GER with symptoms in infants has been well studied, the association of air swallows with similar symptoms has not. We recently showed that a novel application of multichannel intraluminal impedance and pH monitoring (MII-pH) can be used to objectively assess the temporal relationship between air swallows and GER-like symptoms.

Aim:
The purpose of this investigation was to assess the roll of air swallowing in infants presenting with symptoms suggestive of GER as an etiology.

Methods:
We searched our MMS data base for infants (≤12 months) who had been tested using MII-pH from 2014 to 2020. Tracings were excluded if there were significant technical defects or if recording time during non-feeding periods was < 15 hours. Two copies were made of each tracing; the first copy was used to manually tag GER events and the second copy was used to manually tag air swallows. For both tracings, temporal association was tested using the symptom association probability (SAP) index with a positive association set at > 95%. Significantly more air swallows occurred when the esophagus was not acidified (92.2% vs 7.8%, p < 0.0001). In 8 (17.8%) infants, symptoms were significantly associated with only GER. In 38 (84.4%) infants, symptoms were significantly associated with either GER or air swallows. In 14 (36.8%) infants, symptoms were significantly associated with only air swallows.

Discussion:
The data show that air swallows are indeed common in infants. In a study involving a moderately-sized cohort, the data also show that in the absence of MII-pH analyses that includes air swallowing more than a third of infants may not receive a diagnosis. cm/sec, p = 0.01) but numbers were small. Propofol was used for all tube placements, midazolam was given for 2 cases, and ondansetron was given in 3 cases. One child received fentanyl > 2 hr before fasting testing but showed no difference in same vs. next day HAPCs.

Conclusion:
In a small pediatric series undergoing colon manometry for diverse indications, HAPCs were more often seen the day after catheter placement vs. on same day testing. HAPC propagation characteristics on high resolution analyses were similar (except propagation velocity) on next vs. same day recording. HAPC findings were not related to procedure anesthesia. Based on this initial experience, we have adopted next day recordings for colon manometry interpretation while accumulating ongoing data. (4) At 30 min, the plasma insulin level was 18.8 µIU/ml with SIES, which was significantly higher than that with sham (7.1 µIU/ml, p < 0.001) and that with IES (13.2 µIU/ml, p = 0.046). We included the following Outcomes: Total symptoms score (TSS), vomiting, and nausea as primary outcomes. Early satiety, bloating, postprandial fullness, and epigastric pain as the secondary outcomes.

Conclusions
We analyzed continuous data using mean difference (MD) with relative 95% confidence interval (CI).

Results:
We included six clinical trials. We found that the Diabetic GP group show a significant difference from the Idiopathic GP charge/pulse (micro-coulombs), energy/pulse (micro-joules), power/ pulse (milli-watts) and average power (milliwatts). These energy calculations were then adjusted by total cell counts  and the results were compared by non-parametric analyses and reported as median and intra quartiles.   Hirschsprung disease (HSCR), a birth defect in which ENS is missing from distal bowel, removal of bowel that lacks neurons is theoretically curative. However, post-operative outcomes are highly variable. We hypothesize that adverse outcomes after HSCR surgery are linked to structural defects in residual ENS after pull through surgery and that these could be more readily visualized via threedimensional imaging and tissue clearing.

Results
Aims: To visualize and analyze structure and composition of the ENS of healthy pediatric colon as compared to pediatric HSCR colon and adult colon.

Methods:
We utilize tissue clearing, immunohistochemistry, and confocal imaging to visualize human ENS in full-thickness bowel. We compare segments of descending colon obtained from two pediatric organ donors -ages 3 days old and 5 years old -to five HSCR pullthrough resections and four segments from adult colon. Quantitative analyses of images are performed to define ENS anatomy.

Results:
The frequency of gastric contractions ranged from 2.6 to 4.4 contractions/min, with a mean of 3.4 contractions/min ( Figure 1).
The time between the end of contractions and the passage of MoPill into the duodenum signaling that gastric emptying has occurred is shown in Figure 2. The difference between the two endpoints in this pilot study ranged from 1 to 53 minutes with a mean value of 18 minutes. and antrum, the opening and closing of the pylorus, and tonic contractions over the fundus. Such GI-MRI images with high temporal resolution and full coverage of the stomach will enable the characterization of normal gastric dynamics and differentiation from those associated with gastric-related disorders.

Method: We used KT-Generalized Autocalibrating Partially Parallel
Acquisitions (KT-GRAPPA), a parallel imaging technique exploiting spatiotemporal redundancies to reduce acquisition time and obtain full coverage of the stomach at high spatiotemporal resolution as required to capture peristaltic dynamics. We customized the respiration-triggered FLASH sequence to minimize the respiratory artifacts and maximize SNR. A partially sampled scheme in k-space is implemented to speed up the acquisition with a reduction factor of three. It employed between 8 and 16 autocalibration phase encodings (ACS) in the center of the k-space combined with an interleaved acquisition of the peripheral phase encodings. An in-house KT-GRAPPA reconstruction algorithm was also developed for predicting missing phase encodings and reconstructing the images at full resolution.

Results:
We implemented our method on pre-clinical 7T Agilent MRI.
Compared to earlier work, we extended partial spatial coverage of the stomach from 4 slices to full coverage with 12-20 slices per 1.   Background: Radiotherapy for pelvic cancers can lead to radiationinduced visceral organ injuries that frequently develop into persistent chronic radiation proctitis, colitis, and cystitis. One key symptom associated with both of these conditions is pain associated with the affected organ. Currently, no recommended guidelines for the treatment of visceral pain associated with radiotherapy exist, making the management of these conditions extremely challenging. Here, we test the hypothesis that guanylate cyclase-c (GC-C) engagement via GC-C agonist IW-3300 relieves pain in a rat model of pelvic radiation injury.
Methods: Adult male Lewis rats received a fractionated dose of radiation (FR: 48 Gy total over 8 days), a single high dose of radiation (HR: 25 Gy), or sham irradiation. On day 42 colonic sensitivity was assessed via a visceromotor response (VMR) to graded pressures of isobaric colorectal distension (CRD, 20-60 mmHg) and bladder sensitivity was assessed via quantification of suprapubic withdrawal reflex to von Frey filaments (SWR). Rats exposed to fractionated radiation then received intracolonic IW-3300 (3 µg/kg) or vehicle on days 56-72 and rats exposed to a single high dose of radiation received IW-3300 or vehicle on days 42-72. Colonic and bladder sensitivity was reassessed in both groups on days 56 and 72.
Summary: Irradiation of the pelvic region induces persistent colonic and bladder hypersensitivity in adult male rats that is inhibited by GC-C agonist IW-3300. Introduction: While irritable bowel syndrome with diarrhea in IBD patients is frequently described, IBD patients with constipation has not been well described. We aimed to determine prevalence of constipation in IBD patients and their treatment strategies.

Methods:
Consented patients enrolled in a prospective IBD natural history registry at a tertiary referral center formed the study population. Patients with either Crohn's disease (CD) or ulcerative colitis (UC) followed for a minimum of 2 years were included. Patients specifically prescribed the following IBS-C categories of therapy for constipation-related symptoms were included in the study cohort: general constipation, bulk forming laxatives, stimulant laxatives, osmotic laxatives, suppositories, stool softeners, and medications targeting opioid-induced constipation. IBD specific outcomes included frequency of elevated CRP, Harvey-Bradshaw Index (HBI), Ulcerative Colitis Activity Index (UCAI)), and quality of life (Short Inflammatory Bowel Disease Questionnaire (SIBDQ).
Results: Out of 3,299 IBD patients, only 2.9% (n = 97) received a prescription for at least one IBS-C category therapy (53.5% with Crohn's, 46.5% with UC). More women were noted in the IBS-C medication group (57.0% women vs 43.0% men (p = 0.016)). With an overall elevated CRP of 57.7%, there was no significant difference in elevated CRP between those with Crohn's or those with UC. In terms of disease activity/severity, there was no statistically significant difference in median SIBDQ or HBI-UCAI scores between the two disease types. For both Crohn's and UC, increase in age was associated with likelihood to need IBS-C medication (p < 0.004 for Crohn's and p < 0.001 for UC).
Conclusion: In our registry, ~3% of IBD patients required constipation medications during the study period. Patients with Crohn's disease have a slightly higher prevalence of constipation compared to those with UC. Elevated inflammatory markers suggest that the mechanism for constipation in these patients may be driven by an inflammatory-fibrosis type mechanism. Further studies into treatment strategies for constipation in IBD patients may yield improved patient outcomes in this group.  agents, stimulants, and/or stool softeners, which were permitted to continue during the studies, were identified. Efficacy endpoints included rescue-free laxation (RFL) within 4 or 24 hours after the first dose (ie, a spontaneous bowel movement without requiring rescue laxatives) and pain intensity. Safety endpoints included TEAEs.

Results:
The pooled analysis yielded 363 patients with advanced illness. Of those, 286, 167, or 123 patients were using a laxative regimen at baseline that contained a stimulant, osmotic agent, or stool softener, respectively (patients were permitted to use more than 1 type of laxative). A greater proportion of patients who received MNTX (63%-66%) had RFL within 4 hours compared with PBO (14%-21%) regardless of the type of laxative used at baseline (p < 0.0001). Similar findings were observed for those with RFL response within 24 hours of MNTX treatment (72%-77%) vs PBO (43%-46%, p < 0.005). There were no significant differences between MNTX or PBO in the change from baseline pain scores after 1 day or 7 days regardless of the type of laxative used at baseline. The most commonly reported TEAE was abdominal pain.  Rats were exposed to EE (larger cage, additional cage-mates, and toys) 1 week before and during WAS. Control rats were kept in standard housing (SH). Somatic sensitivity was measured using an electronic von Frey on the hind paw and visceral sensitivity was assessed by measuring the number of abdominal contractions to isobaric colorectal distensions (20, 40 and 60 mmHg) in freely moving rats on day 8. All rats were then put in SH for 3 weeks and viscerosomatic sensitivity assessed again on day 28 before the spinal cords were collected to quantify pERK expression as a measure of neuronal activation. Another cohort was euthanized on day 8 and the CeA collected to measure epigenetic changes at the glucocorticoid (GR) and corticotropin releasing hormone (CRH) promoter regions.

Conclusions
Results were analyzed using 1-or 2-way ANOVA.
Results: Exposure to EE prevented WAS induced visceral hypersensitivity (p < 0.01) and somatic allodynia (p < 0.001) and these effects were persistent up to day 28. EE also prevented stress-induced increase in H3K9 acetylation at the CRH promoter (p < 0.001), decreased H3k9 acetylation at the GR promoter (p < 0.001) and decreased GR-CRH interaction (p < 0.01) in the CeA and blocked stressinduced increase in pERK expression at the dorsal horn (p < 0.0001). following graded pressure (0-60 mmHg) of isobaric distension.

Conclusions
Microglial morphology, microglia-mediated synaptic engulfment and the expression of synaptic pruning-related signals complement C1q and C3R receptor were measured using immunofluorescence and RNAscope assay.

Summary:
Our data suggest that exposure to EE is able to ameliorate stress-induced visceral pain via reducing amygdala microglial activity and microglia-modulated neuronal plasticity. By using the experimental EE paradigm, we uncovered a potential mechanism through which CBT attenuates visceral pain in IBS patients. Methods: The first group of female rats were exposed daily to 1 hour of WAS or SHAM for 7 consecutive days. The second group underwent stereotaxic implantation of indwelling cannulas directly above the CeA, before being exposed to 1 hour of WAS for 7 consecutive days. Each WAS session was followed by infusion of the HDAC inhibitor TSA (100 ng/µl) or vehicle (VEH) in the CeA. Twentyfour hours after the final stressor/infusion, visceral sensitivity was assessed in freely moving rats by quantifying the number of abdominal contractions induced by colorectal distension at isobaric pressures (20, 40 and 60 mmHg). In another cohort, the CeA was isolated for chromatin immunoprecipitation of acetylated histone 3 lysine 9

Sex differences in neurogastroenterology and
(H3K9) and amplification of the GR and CRH promoter regions.

Results:
After WAS, female rats showed an increased number of abdominal contractions when compared to SHAM rats (at 60 mmHg: 38 ± 3 vs 25 ± 3, p < 0.0001). WAS caused a 54% decrease in H3K9 acetylation at the GR promoter (9.5 ± 7.3 vs 20.5 ± 8.7, p < 0.048) and a 102% increase in H3K9 acetylation at the CRH promoter (10.3 ± 5.7 vs 5.11 ± 3.7, p < 0.045). Administration of TSA after WAS reduced the number of abdominal contractions when compared to WAS+VEH (at 60 mmHg: 21 ± 1 vs 39 ± 4, p < 0.0001). TSA after WAS also prevented the decrease of H3K9 acetylation at the GR promoter when compared to WAS+VEH (17.0 ± 6.8 vs 7.3 ± 8.3, p < 0.0058). intestine is greater than the length of the small intestine (approximately 7 meters) that could suggest retrograde motion and segmentation. If the total distance that the capsule travels in the SI is divided by 7, it provides a multiple of the SI travel and could serve as a segmentation index.

Methods:
In a pilot study 9 normal subjects (4 Female; mean BMI 25; and 5 Male mean BMI 23) were given a 250 calorie protein bar and water after an overnight fast and ingested activated MoPill capsule at the same time. The distance the capsule traveled while in the small intestine was divided by 7 to calculate a segmentation index.

Results:
The results of the segmental index for all subjects are presented in Figure 1 based on gender (in descending order), while Figure 2 shows the average (11.3 vs.6.1), and range (25.7 vs.6.9) of the Segmental Index which was higher in female than male participants.

Conclusion:
Though this is a very small study, it appears that females have more segmentation in their small intestine than do males which may lead to greater extraction of nutrients and more weight gain in females than males for similar caloric ingestion. These results need to be verified with a larger study. MoPill is new technology that may be an objective diagnostic tool for assessing the degree of small bowel segmentation as well as transit abnormalities.