Mass General - Division of Clinical Research

FOR SYMPTOMATIC PARTICIPANTS: 1. Provision of signed and dated informed consent form. 2. Stated willingness to comply with all study procedures and availability for the duration of the study. 3. Male or female, aged 18-85 4. Symptoms of gastroparesis, either diabetic or idiopathic etiology 5. Symptoms of gastroparesis with minimum Gastroparesis Cardinal Symptom Index (GCSI) score of 2.0 6. Individual will have had a prior 4-hour gastric emptying scintigraphy test performed for clinical evaluation within the last 6 months. This gastric emptying test would be done for clinical evaluation and is not part of the research study. From these participants with gastroparesis symptoms, we will include those with delayed gastric emptying as well as those with normal gastric emptying. 7. Participant must not initiate any new treatments until completion of the study procedures. 8. Willingness to: 1. Stop histamine 2 antagonists, prokinetics (e.g., metoclopramide, erythromycin, domperidone, prucalopride), narcotics, anticholinergics, constipation medications (over the counter laxatives, isotonic polyethylene glycol (PEG) electrolyte preparations (e.g. MiraLax), prescription laxatives (e.g. lubiprostone), proton pump inhibitors, cannabinoids, and cannabidiol (CBD) for 3 days prior to each visit; 2. Abstain from food and water after midnight (at least for 8 hours) before the start of each visit until after the visit. INCLUSION CRITERIA FOR CONTROL PARTICIPANTS 1. Provision of signed and dated informed consent form 2. Male or female, aged 18 or older 3. Undergoing an upper endoscopy for their clinical evaluation of diarrhea, GI bleed, or iron-deficiency anemia, or evaluation for bariatric surgery. 4. Do not have upper GI symptoms greater than 1 as assessed by the Gastroparesis Cardinal Symptom Index (GCSI) of PAGI-SYM questionnaire.

1. Prior gut lumen surgery on the esophagus or the stomach, including Nissen fundoplication. 2. Prior surgery on the pylorus (G-POEM, surgical pyloroplasty, surgical pyloromyotomy) 3. Known history of achalasia or esophageal stricture 4. Known history of physiological or mechanical GI obstruction 5. Abnormalities seen on a prior upper endoscopy placing patient at increased risk: - Ulcer of the esophagus, stomach, or duodenum - Esophageal varices 6. Individuals at risk for prolonging the endoscopy procedure: severe chronic pulmonary disease, severe food retention in the stomach on endoscopy. 7. Presence of significant gastric or duodenal pathology that could be expected to cause dysmotility (e.g. significant inflammation, infiltrate disorders etc) 8. Individuals with a history of other chronic disease potentially causative of gastrointestinal symptom 9. Acute or chronic renal insufficiency 10. Current eating disorders 11. Females who are pregnant. A urine pregnancy test is routinely obtained on all females immediately prior to endoscopic procedures. 12. Individuals with contraindications for endoscopy, including bleeding abnormalities 13. Allergy to eggs preventing sedation with propofol and/or gastric emptying test 14. Significant dysphagia 15. Prior inflammatory bowel disease, Crohn's 16. History of any esophageal/gastric/pyloric injection of botulinum toxin 17. Patients on daily opioid use or >3 day/week use 18. Use of glucagon-like peptide 1 (GLP1) receptor agonists or Sodium-Glucose Transport Protein 2 (SGLT2); Gastric inhibitory polypeptide (GIP)- glucagon-like peptide (GLP) combo