Novel and validated approaches for gastric emptying scintigraphy in patients with suspected gastroparesis

Safe Continuation of Glucagon-like Peptide 1 Receptor Agonists at Endoscopy: A Case Series of 57 Adults Undergoing Endoscopic Sleeve Gastroplasty

PURPOSE

Glucagon-like receptor agonists (GLP1-RAs) have raised peri-procedural concerns due to their potential to delay gastric emptying. The American Association of Anesthesiologists has advised pausing a single dose before elective endoscopy. However, a subsequent directive from multiple gastroenterology societies underscored the need for further assessment to substantiate this practice. We aimed to evaluate the frequency of serious adverse events and retained gastric products during endoscopic sleeve gastroplasty (ESG) with uninterrupted GLP1-RA use.

MATERIALS AND METHODS

We conducted a retrospective evaluation of all patients undergoing ESG while on GLP1-RAs at three centers from August 2022 to February 2024. Per standard protocol, all patients had refrained from solid foods for at least 24 h and maintained nil per os for 12 h preceding their ESG. Records were reviewed for patient characteristics and medication type and doses. Primary outcomes included serious adverse events and retained gastric products based on patient records, procedure reports, and procedural videos.

RESULTS

Fifty-seven consecutive adults (89.5% women, mean age of 44 ± 9 years, mean BMI of 40.1 ± 8.1 kg/m2, 35.1% with T2DM, and 26.3% with pre-T2DM) underwent ESG without stopping GLP1-RAs, which included semaglutide (45.6%), liraglutide (19.3%), dulaglutide (22.8%), and tirzepatide (12.3%). During intubation, endoscopy, and recovery, there were no instances of retained gastric solids, pulmonary aspiration, gastroesophageal regurgitation, or hypoxia.

CONCLUSION

A ≥ 24-h pre-endoscopy liquid-only diet with ≥ 12-h pre-endoscopy fast may negate the need for GLP1-RA interruption for routine upper endoscopy in adults with native gastric anatomy.

Meal effects on gastric bioelectrical activity utilizing body surface gastric mapping in healthy subjects

BACKGROUND

Gastric sensorimotor disorders are prevalent. While gastric emptying measurements are commonly used, they may not fully capture the underlying pathophysiology. Body surface gastric mapping (BSGM) recently emerged to assess gastric sensorimotor dysfunction. This study assessed varying meal size on BSGM responses to inform test use in a wider variety of contexts.

METHODS

Data from multiple healthy cohorts receiving BSGM were pooled, using four different test meals. A standard BSGM protocol was employed: 30-min fasting, 4-h post-prandial, using Gastric Alimetry® (Alimetry, New Zealand). Meals comprised: (i) nutrient drink + oatmeal bar (482 kcal; 'standard meal'); (ii) oatmeal bar alone; egg and toast meal, and pancake (all ~250 kcal). Gastric Alimetry metrics included BMI-adjusted Amplitude, Principal Gastric Frequency, Gastric Alimetry Rhythm Index (GA-RI) and Fed:Fasted Amplitude Ratio (ff-AR).

KEY RESULTS

238 participants (59.2% female) were included. All meals significantly increased amplitude and frequency during the first postprandial hour (p < 0.05). There were no differences in postprandial frequency across meals (p > 0.05). The amplitude and GA-RI of the standard meal (n = 110) were significantly higher than the energy bar alone (n = 45) and egg meal (n = 65) (all p < 0.05). All BSGM metrics were comparable across the three smaller meals (p > 0.05). A higher symptom burden was found in the oatmeal bar group versus the standard meal and pancake meal (p = 0.01, 0.003, respectively).

CONCLUSIONS & INFERENCES

The consumption of lower calorie meals elicited different postprandial responses, when compared to the standard Gastric Alimetry meal. These data will guide interpretations of BSGM when applied with lower calorie meals.

The role of gastric function in control of food intake (and body weight) in relation to obesity, as well as pharmacological and surgical interventions

PURPOSE

The objectives of this review are to summarize the role of gastric motor functions in the development of satiation (defined broadly as postprandial fullness) and satiety (reduced appetite or postponing desire to eat after a meal) and their impact on weight change. The specific topics are the methods of measurement of gastric emptying and accommodation and their impact on food intake, satiation, and satiety. A second focus contrasts bariatric surgery to endoscopic gastroplasty that alter gastric emptying and incretin responses in markedly divergent manners.

BACKGROUND

The hormone, GLP-1, retards gastric emptying and increases gastric accommodation through vagally-mediated effects. Indeed, these effects provide the basis for the association of altered gastric emptying in the appetite and weight loss responses to pharmacological interventions particularly by those acting on receptors of incretin agonists such as liraglutide and the dual agonists, tirzepatide and cotadutide, all of which retard gastric emptying. In fact, retardation of gastric emptying and gastrointestinal adverse effects have been shown to contribute in part to the weight loss in response to this class of pharmacological agents.

SUMMARY

The motor functions of the stomach are relevant to postprandial fullness and to interventions aimed at weight loss in people with obesity.

Review article: Pharmacologic management of obesity - updates on approved medications, indications and risks

BACKGROUND

Obesity has reached epidemic proportions, with >40% of the US population affected. Although traditionally managed by lifestyle modification, and less frequently by bariatric therapies, there are significant pharmacological advancements.

AIMS

To conduct a narrative review of the neurohormonal and physiological understanding of weight gain and obesity, and the development, clinical testing, indications, expected clinical outcomes, and associated risks of current FDA-approved and upcoming anti-obesity medications (AOMs).

METHODS

We conducted a comprehensive review in PubMed for articles on pathophysiology and complications of obesity, including terms 'neurohormonal', 'obesity', 'incretin', and 'weight loss'. Next, we searched for clinical trial data of all FDA-approved AOMs, including both the generic and trade names of orlistat, phentermine/topiramate, bupropion/naltrexone, liraglutide, and semaglutide. Additional searches were conducted for tirzepatide and retatrutide - medications expecting regulatory approval. Searches included combinations of terms related to mechanism of action, indications, side effects, risks, and future directions.

RESULTS

We reviewed the pathophysiology of obesity, including specific role of incretins and glucagon. Clinical data supporting the use of various FDA-approved medications for weight loss are presented, including placebo-controlled or, when available, head-to-head trials. Beneficial metabolic effects, including impact on liver disease, adverse effects and risks of medications are discussed, including altered gastrointestinal motility and risk for periprocedural aspiration.

CONCLUSION

AOMs have established efficacy and effectiveness for weight loss even beyond 52 weeks. Further pharmacological options, such as dual and triple incretins, are probable forthcoming additions to clinical practice for combating obesity and its metabolic consequences such as metabolic dysfunction-associated steatotic liver disease.

A global bibliometric and visualized analysis of the status and trends of gastroparesis research

BACKGROUND

Gastroparesis has a substantial impact on the quality of life but has limited treatment options, which makes it a public health concern. No bibliometric studies on gastroparesis have been published thus far. Thus, this article aims to summarize and analyze research hotspots to provide a reference for clinical researchers.

MATERIALS AND METHODS

Gastroparesis-related research articles were searched in the Web of Science Core Collection (WOSCC), and relevant information was extracted after screening. A total of 1033 documents were analyzed with the bibliometric method using Microsoft Excel, Citespace, and VOSviewer.

RESULTS

Overall, our search retrieved 1033 papers contributed by 966 research institutions from 53 countries. Since 1980, publications in this field have increased rapidly. United States (n = 645) and Temple University (n = 122) were the most productive country and institution, respectively. Parkman, with 96 publications, was the most prominent author.

CONCLUSIONS

Research hotspots in gastroparesis can be summarized into four domains: innovation in diagnostic modalities, change of oral therapeutic agents, choice of surgical interventions, and pathological mechanisms. Future research on gastroparesis should focus on the quality of life of patients, diagnostic techniques, pyloromyotomy, and transpyloric stent placement.

Abnormal gastrointestinal motility is a major factor in explaining symptoms and a potential therapeutic target in patients with disorders of gut-brain interaction

The objective of this article is to review the evidence of abnormal gastrointestinal (GI) tract motor functions in the context of disorders of gut-brain interaction (DGBI). These include abnormalities of oesophageal motility, gastric emptying, gastric accommodation, colonic transit, colonic motility, colonic volume and rectal evacuation. For each section regarding GI motor dysfunction, the article describes the preferred methods and the documented motor dysfunctions in DGBI based on those methods. The predominantly non-invasive measurements of gut motility as well as therapeutic interventions directed to abnormalities of motility suggest that such measurements are to be considered in patients with DGBI not responding to first-line approaches to behavioural or empirical dietary or pharmacological treatment.

Overview of the Enteric Nervous System

Propulsion of contents in the gastrointestinal tract requires coordinated functions of the extrinsic nerves to the gut from the brain and spinal cord, as well as the neuromuscular apparatus within the gut. The latter includes excitatory and inhibitory neurons, pacemaker cells such as the interstitial cells of Cajal and fibroblast-like cells, and smooth muscle cells. Coordination between these extrinsic and enteric neurons results in propulsive functions which include peristaltic reflexes, migrating motor complexes in the small intestine which serve as the housekeeper propelling to the colon the residual content after digestion, and mass movements in the colon which lead to defecation.

Gastrointestinal Dysmotility in Critically Ill Patients: Bridging the Gap Between Evidence and Common Misconceptions

Disruption of normal gastrointestinal (GI) function in critical illness is linked to increased morbidity and mortality, and GI dysmotility is frequently observed in patients who are critically ill. Despite its high prevalence, the diagnosis and management of GI motility problems in the intensive care unit remain very challenging, given that critically ill patients often cannot verbalize symptoms and the general lack of understanding of underlying pathophysiology. Common clinical presentations of GI dysmotility issues among critically ill patients include: (1) high gastric residual volumes, acid reflux, and vomiting, (2) abdominal distention, and (3) diarrhea. In this review, we discuss the differential diagnosis for intensive care unit patients with symptoms and signs concerning GI motility issues. There are many myths and longstanding misconceptions about the diagnosis and management of GI dysmotility in critical illness. Here, we uncover these myths and discuss relevant evidence in each subject area, with the goal of re-conceptualizing GI motility disorders in critical care and providing evidence-based recommendations for clinical care.

Gastroparesis

Gastroparesis is characterized by symptoms suggestive of, and objective evidence of, delayed gastric emptying in the absence of mechanical obstruction. This review addresses the normal emptying of solids and liquids from the stomach and details the myogenic and neuromuscular control mechanisms, including the specialized function of the pyloric sphincter, that result in normal emptying, based predominantly on animal research. A clear understanding of fundamental mechanisms is necessary to comprehend derangements leading to gastroparesis, and additional research on human gastric muscles is needed. The section on pathophysiology of gastroparesis considers neuromuscular diseases that affect nonsphincteric gastric muscle, disorders of the extrinsic neural control, and pyloric dysfunction that lead to gastroparesis. The potential cellular basis for gastroparesis is attributed to the effects of oxidative stress and inflammation, with increased pro-inflammatory and decreased resident macrophages, as observed in full-thickness biopsies from patients with gastroparesis. Predominant diagnostic tests involving measurements of gastric emptying, the use of a functional luminal imaging probe, and high-resolution antral duodenal manometry in characterizing the abnormal motor functions at the gastroduodenal junction are discussed. Management is based on supporting nutrition; dietary interventions, including the physical reduction in particle size of solid foods; pharmacological agents, including prokinetics and anti-emetics; and interventions such as gastric electrical stimulation and pyloromyotomy. These are discussed briefly, and comment is added on the potential for individualized treatments in the future, based on optimal gastric emptying measurement and objective documentation of the underlying pathophysiology causing the gastroparesis.

United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on gastroparesis

BACKGROUND

Gastroparesis is a condition characterized by epigastric symptoms and delayed gastric emptying (GE) rate in the absence of any mechanical obstruction. The condition is challenging in clinical practice by the lack of guidance concerning diagnosis and management of gastroparesis.

METHODS

A Delphi consensus was undertaken by 40 experts from 19 European countries who conducted a literature summary and voting process on 89 statements. Quality of evidence was evaluated using grading of recommendations assessment, development, and evaluation criteria. Consensus (defined as ≥80% agreement) was reached for 25 statements.

RESULTS

The European consensus defined gastroparesis as the presence of symptoms associated with delayed GE in the absence of mechanical obstruction. Nausea and vomiting were identified as cardinal symptoms, with often coexisting postprandial distress syndrome symptoms of dyspepsia. The true epidemiology of gastroparesis is not known in detail, but diabetes, gastric surgery, certain neurological and connective tissue diseases, and the use of certain drugs recognized as risk factors. While the panel agreed that severely impaired gastric motor function is present in these patients, there was no consensus on underlying pathophysiology. The panel agreed that an upper endoscopy and a GE test are required for diagnosis. Only dietary therapy, dopamine-2 antagonists and 5-HT₄ receptor agonists were considered appropriate therapies, in addition to nutritional support in case of severe weight loss. No consensus was reached on the use of proton pump inhibitors, other classes of antiemetics or prokinetics, neuromodulators, complimentary, psychological, or more invasive therapies. Finally, there was consensus that gastroparesis adversely impacts on quality of life and healthcare costs and that the long-term prognosis of gastroparesis depends on the cause.

CONCLUSIONS AND INFERENCES

A multinational group of European experts summarized the current state of consensus on definition, symptom characteristics, pathophysiology, diagnosis, and management of gastroparesis.

United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on gastroparesis

Background

Gastroparesis is a condition characterized by epigastric symptoms and delayed gastric emptying (GE) rate in the absence of any mechanical obstruction. The condition is challenging in clinical practice by the lack of guidance concerning diagnosis and management of gastroparesis.

Methods

A Delphi consensus was undertaken by 40 experts from 19 European countries who conducted a literature summary and voting process on 89 statements. Quality of evidence was evaluated using grading of recommendations assessment, development, and evaluation criteria. Consensus (defined as ≥80% agreement) was reached for 25 statements.

Results

The European consensus defined gastroparesis as the presence of symptoms associated with delayed GE in the absence of mechanical obstruction. Nausea and vomiting were identified as cardinal symptoms, with often coexisting postprandial distress syndrome symptoms of dyspepsia. The true epidemiology of gastroparesis is not known in detail, but diabetes, gastric surgery, certain neurological and connective tissue diseases, and the use of certain drugs recognized as risk factors. While the panel agreed that severely impaired gastric motor function is present in these patients, there was no consensus on underlying pathophysiology. The panel agreed that an upper endoscopy and a GE test are required for diagnosis. Only dietary therapy, dopamine‐2 antagonists and 5‐HT₄ receptor agonists were considered appropriate therapies, in addition to nutritional support in case of severe weight loss. No consensus was reached on the use of proton pump inhibitors, other classes of antiemetics or prokinetics, neuromodulators, complimentary, psychological, or more invasive therapies. Finally, there was consensus that gastroparesis adversely impacts on quality of life and healthcare costs and that the long‐term prognosis of gastroparesis depends on the cause.

Conclusions and Inferences

A multinational group of European experts summarized the current state of consensus on definition, symptom characteristics, pathophysiology, diagnosis, and management of gastroparesis.

Current knowledge

The epidemiology of gastroparesis is not well known.

Diagnosis and treatment of gastroparesis is challenging due to uncertainties in definition and optimal therapeutic approach.

What is new here

A Delphi panel consisting of 40 experts from 19 European countries established the level of consensus on 89 statements regarding gastroparesis.

The statements reaching consensus serve to guide clinicians in recognizing, diagnosing and treating gastroparesis in clinical practice.

The statements without consensus identify areas in need of future research.

Relationship of motor mechanisms to gastroparesis symptoms: toward individualized treatment

Following a classical paper by Dr. Keith A. Kelly published in this journal, and over the past 40 years, there has been increased understanding of the functions of different regions of the stomach, specifically the fundus, antrum, and pylorus. Several of the important physiological principles were based on in vivo animal studies that led to the appreciation of regional function and control mechanisms. These include the roles of the extrinsic parasympathetic vagal innervation, the gastric enteric nervous system and electrical syncytium consisting of pacemaker cells and smooth muscle cells, and duodenogastric reflexes providing feedback regulation following the arrival of food and hydrogen ions stimulating the release of hormones and vagal afferent mechanisms that inhibit gastric motility and stimulate pyloric contractility. Further insights on the role of regional motor functions in gastric emptying were obtained from observations in patients following diverse gastric surgeries or bariatric procedures, including fundoplication, Billroth I and sleeve gastrectomy, and sleeve gastroplasty. Antropyloroduodenal manometry and measurements of pyloric diameter and distensibility index provided important assessments of the role of antral hypomotility and pylorospasm, and these constitute specific targets for individualized treatment of patients with gastroparesis. Moreover, in patients with upper gastrointestinal symptoms suggestive of gastroparesis, the availability of measurements of gastric accommodation and pharmacological agents to reduce gastric sensitivity or enhance gastric accommodation provide additional specific targets for individualized treatment. It is anticipated that, in the future, such physiological measurements will be applied in patients to optimize choice of therapy, possibly including identifying the best candidate for pyloric interventions.

Gastroesophageal Reflux Disease and Foregut Dysmotility in Children with Intestinal Failure

Gastrointestinal dysmotility is a common problem in a subgroup of children with intestinal failure (IF), including short bowel syndrome (SBS) and pediatric intestinal pseudo-obstruction (PIPO). It contributes significantly to the increased morbidity and decreased quality of life in this patient population. Impaired gastrointestinal (GI) motility in IF arises from either loss of GI function due to the primary disorder (e.g., neuropathic or myopathic disorder in the PIPO syndrome) and/or a critical reduction in gut mass. Abnormalities of the anatomy, enteric hormone secretion and neural supply in IF can result in rapid transit, ineffective antegrade peristalsis, delayed gastric emptying or gastroesophageal reflux. Understanding the underlying pathophysiologic mechanism(s) of the enteric dysmotility in IF helps us to plan an appropriate diagnostic workup and apply individually tailored nutritional and pharmacological management, which might ultimately lead to an overall improvement in the quality of life and increase in enteral tolerance. In this review, we have focused on the pathogenesis of GI dysmotility in children with IF, as well as the management and treatment options.

Gastric Per Oral Pyloromyotomy for Post-Vagotomy-Induced Gastroparesis Following Esophagectomy

BACKGROUND

Following the success of per-oral endoscopic myotomy (POEM) for achalasia, application of this minimally invasive skillset has broadened to other disease processes. Since 2013, gastric per-oral pyloromyotomy (GPOP) has become an increasingly accepted therapy for refractory gastroparesis. Although it does not treat the underlying etiology of the disease, pyloromyotomy has demonstrated measurable improvements in gastric emptying scintigraphy, nausea, and quality of life. Gastroparesis is a common complication of esophagectomy due to the inherent vagotomy that occurs during creation of the gastric conduit. Fifteen to 30% of post-esophagectomy patients develop gastroparesis with a large portion of them reporting symptoms refractory to medical therapy, botox injection, and endoscopic dilation. Therefore, GPOP may have the potential to offer symptomatic relief to a significant population of debilitated post-esophagectomy patients.

MATERIALS AND METHODS

The procedure was recorded using standard operating room equipment. Materials utilized included high-definition single-channel gastroscope, therapeutic overtube, clear endoscopic cap, triangle tip (TT) knife, ERBE energy source, endoscopic clips, sclerotherapy needle, methylene blue with epinephrine, and CO₂ insufflator.

RESULTS

We present a video of GPOP for a 71-year-old male with post-vagotomy-induced gastroparesis after esophagectomy. His pre-operative course was significant for persistent nausea and vomiting, diet intolerance, 20 lb weight loss, and frequent hospitalizations for aspiration pneumonia. Post-operatively, the patient recovered well and was discharged home on post-operative day 1 on a liquid diet. At 3-week follow-up, his nausea, vomiting, and PO intolerance had improved. At 6-month follow-up, he had no recent admissions for aspiration pneumonia and his pylorus remained widely patent on EGD.

CONCLUSIONS

GPOP status post-esophagectomy presented multiple challenges: difficulty maintaining field of view and insufflation, establishing tension and counter tension for the mucosotomy, and a limited working space. With care and patience, endoscopists trained to perform POEM may apply their skillset to help a large population of patients suffering with post-esophagectomy gastroparesis.

Role of Gastric Emptying in Symptoms of Gastroparesis

The symptoms of gastroparesis, such as nausea, vomiting, postprandial fullness, early satiety and abdominal pain, frequently impair the quality of life of the affected individuals. The diagnosis of gastroparesis is made after structural etiologies are ruled out and an assessment of gastric function shows delayed gastric emptying. The role of the delay in gastric emptying in the pathogenesis of symptoms of gastroparesis has been debated, with some studies suggesting an association between delayed gastric emptying and the upper gastrointestinal symptoms, while others do not. The recent literature supports the importance of using reliable methods to assess gastric emptying, as delay in gastric emptying measured on a reliable test (4-h scintigraphy or breath test) is associated with the severity of upper gastrointestinal symptoms. In addition to measuring total gastric emptying, evaluation of regional gastric retention in the proximal and distal stomach and whole gut transit to assess small intestinal and colonic transit may provide additional useful information in patients with more generalized symptoms of gastrointestinal dysmotility.

GI Motility Testing: Stomach, Small Bowel, and Colon

Symptoms of abdominal pain, nausea, vomiting, bloating, abdominal distention, diarrhea, and constipation are common and may relate to abnormalities in gastrointestinal motility. There are a number of different options to study gastrointestinal motility. This article reviews novel and standard motility tests available in the stomach, small bowel, and colon. The indications for testing, technical details, advantages, and disadvantages of each test will be summarized.

Unhealthy gut, unhealthy brain: The role of the intestinal microbiota in neurodegenerative diseases

The number of bacterial cells living within the human body is approximately equal to, or greater than, the total number of human cells. This dynamic population of microorganisms, termed the human microbiota, resides mainly within the gastrointestinal tract. It is widely accepted that highly diverse and stable microbiota promote overall human health. Colonization of the gut with maladaptive and pathogenic microbiota, a state also known as dysbiosis, is associated with a variety of peripheral diseases ranging from type 2 diabetes mellitus to cardiovascular and inflammatory bowel disease. More recently, microbial dysbiosis has been associated with a number of brain pathologies, including autism spectrum disorder, Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), suggesting a direct or indirect communication between intestinal bacteria and the central nervous system (CNS). In this review, we illustrate two pathways implicated in the crosstalk between gut microbiota and CNS involving 1) the vagus nerve and 2) transmission of signaling molecules through the circulatory system and across the blood-brain barrier (BBB). We summarize the available evidence of the specific changes in the intestinal microbiota, as well as microorganism-induced modifications to intestinal and BBB permeability, which have been linked to several neurodegenerative disorders including ALS, AD, and PD. Even though each of these diseases arises from unique pathogenetic mechanisms, all are characterized, at least in part, by chronic neuroinflammation. We provide an interpretation for the substantial evidence that healthy intestinal microbiota have the ability to positively regulate the neuroimmune responses in the CNS. Even though the evidence is mainly associative, it has been suggested that bacterial dysbiosis could contribute to an adverse neuroinflammatory state leading to increased risk of neurodegenerative diseases. Thus, developing strategies for regulating and maintaining healthy intestinal microbiota could be a valid approach for lowering individual risk and prevalence of neurodegenerative diseases.

The Gastrointestinal Tract as an Integrator of Mechanical and Hormonal Response to Nutrient Ingestion

Glucose tolerance after meal ingestion in vivo is the result of multiple processes that occur in parallel. Insulin secretion together with reciprocal inhibition of glucagon secretion contributes to glucose tolerance. However, other factors beyond glucose effectiveness and insulin action require consideration. The absorption of ingested nutrients and their subsequent systemic rate of appearance largely depend on the rate of delivery of nutrients to the proximal small intestine. This is determined by the integrated response of the upper gastrointestinal tract to a meal. While gastric emptying is probably the most significant component, other factors need to be considered. This review will examine all processes that could potentially alter the fraction and rate of appearance of ingested nutrients in the peripheral circulation. Several of these processes may be potential therapeutic targets for the prevention and treatment of diabetes. Indeed, there is increased interest in gastrointestinal contributions to nutritional homeostasis, as demonstrated by the advent of antidiabetes therapies that alter gastrointestinal motility, the effect of bariatric surgery on diabetes remission, and the potential of the intestinal microbiome as a modulator of human metabolism. The overall goal of this review is to examine current knowledge of the gastrointestinal contributions to metabolic control.

Novel Diet, Drugs, and Gastric Interventions for Gastroparesis

This review of the pathophysiologic basis for gastroparesis and recent advances in the treatment of patients with gastroparesis shows that there are several novel approaches to advance treatment of gastroparesis including diet, novel prokinetics, interventions on the pylorus, and novel forms of gastric electrical stimulation. The field of gastroparesis is likely to advance with further studies, with help from a guidance document from the Food and Drug Administration on gastroparesis, and with recent approval of the stable isotope gastric emptying test to ensure eligibility of participants in multicenter trials. Clinical experience and a formal, randomized, controlled trial provide insights on optimizing dietary interventions in patients with gastroparesis. This review addresses the biologic rationale of these different treatments, based on known physiology and pathophysiology of gastric emptying. The novel medications include the motilin agonist, camicinal; 5-HT4 receptor agonists, such as velusetrag; and the ghrelin agonist, relamorelin. New approaches target pylorospasm by stent placement, endoscopic pyloric myotomy, or laparoscopic pyloroplasty. These approaches offer the opportunity to achieve more permanent reduction of resistance to flow at the pylorus over the intrapyloric injection of botulinum toxin, which typically has to be repeated every few months if it is efficacious. A novel device, deployed in porcine stomach, involved per-endoscopic electrical stimulation. These promising approaches require formal, randomized, controlled trials and deployment in patients. The presence of concomitant antral hypomotility may be a significant factor in the responsiveness to interventions at the pylorus.

Drug-resin drug interactions in patients with delayed gastric emptying: What is optimal time window for drug administration?

Most drug-drug interactions involve overlap or competition in drug metabolic pathways. However, there are medications, typically resins, whose function is to bind injurious substances such as bile acids or potassium within the digestive tract. The objective of this article is to review the functions of the stomach and the kinetics of emptying of different food forms or formulations to make recommendations on timing of medication administration in order to avoid intragastric drug interactions. Based on the profiles and kinetics of emptying of liquid nutrients and homogenized solids, a window of 3 h between administration of a resin drug and another 'target' medication would be expected to allow a median of 80% of medications with particle size <1 mm to empty from the stomach and, hence, avoid potential interaction such as binding of the 'target' medication within the stomach.

Functional Dyspepsia and Gastroparesis

BACKGROUND

Upper gastrointestinal disorders typically present with common symptoms. The most relevant non-mucosal diseases are gastroparesis, functional dyspepsia and rumination syndrome. The literature pertaining to these 3 conditions was reviewed.

KEY MESSAGES

Gastroparesis is characterized by delayed gastric emptying in the absence of mechanical obstruction of the stomach. The cardinal symptoms include postprandial fullness (early satiety), nausea, vomiting and bloating. The most frequently encountered causes of these symptoms are mechanical obstruction (pyloric stenosis), iatrogenic disease, gastroparesis, functional dyspepsia, cyclical vomiting and rumination syndrome. The most common causes of gastroparesis are neuropathic disorders such as diabetes, idiopathic, post-vagotomy and scleroderma among myopathic disorders. Principles of management of gastroparesis include exclusion of mechanical obstruction with imaging and iatrogenic causes with careful medication and past surgical history. Prokinetics and anti-emetics are the mainstays of treatment. Functional dyspepsia is characterized by the same symptoms as gastroparesis; in addition to delayed gastric emptying, pathophysiological abnormalities include accelerated gastric emptying, impaired gastric accommodation and gastric or duodenal hypersensitivity to distension and nutrients. Novel treatments include tricyclic antidepressants in patients with normal gastric emptying, acotiamide (acetyl cholinesterase inhibitor) and 5-HT1A receptor agonists such as buspirone. Rumination syndrome is characterized by repetitive regurgitation of gastric contents occurring within minutes after a meal. Episodes often persist for 1-2 h after the meal, and the regurgitant consists of partially digested food that is recognizable in its taste. Regurgitation is typically effortless or preceded by a sensation of belching. This has been summarized as a 'meal in, meal out, day in, day out' behavior for weeks or months, differentiating rumination from gastroparesis. Patients often have a background of psychological disorder or a prior eating disorder. Treatment is based on behavioral modification.

CONCLUSION

Precise identification of the cause and pathophysiology of upper gastrointestinal symptoms is essential for optimal management.

Measurement of Gastrointestinal and Colonic Motor Functions in Humans and Animals

Accurately measuring the complex motor behaviors of the gastrointestinal tract has tremendous value for the understanding, diagnosis and treatment of digestive diseases. This review synthesizes the literature regarding current tests that are used in both humans and animals. There remains further opportunity to enhance such tests, especially when such tests are able to provide value in both the preclinical and the clinical settings.

Gastric Emptying in the Elderly

Aging is characterized by a diminished homeostatic regulation of physiologic functions, including slowing of gastric emptying. Gastric and small intestinal motor and humoral mechanisms in humans are complex and highly variable: ingested food is stored, mixed with digestive enzymes, ground into small particles, and delivered as a liquefied form into the duodenum at a rate allowing efficient digestion and absorption. In healthy aging, motor function is well preserved whereas deficits in sensory function are more apparent. The effects of aging on gastric emptying are relevant to the absorption of oral medications and the regulation of appetite, postprandial glycemia, and blood pressure.

Gastroparesis in children

PURPOSE OF REVIEW

Gastroparesis is a disorder with delayed gastric emptying in the absence of mechanical obstruction. It is one of the more common dysmotilities that occur in the gastrointestinal tract, and is thought to primarily affect adults. Pediatric cases of gastroparesis were considered rare; however, recent evidence suggests growing recognition in children and adolescents. Therefore, it is important for the pediatric caregiver to understand the condition and the treatment options available.

RECENT FINDINGS

The majority of patients are women, and presentation is usually with symptoms of persistent nausea, emesis, postprandial pain and bloating, and early satiety. Weight loss may occur in some cases, though this is not universal. The majority of cases are idiopathic, with diabetes mellitus the second most common cause.

SUMMARY

Treatment consists of symptomatic relief with medication to counteract the nausea, emesis, pain, bloating, gastroesophageal reflux, early satiety, and improve gastric emptying. Dietary modification is also used with small meals and avoidance of high fiber and fat-containing foods. Recalcitrant cases of gastroparesis require the use of additional approaches such as jejunal feeds, intrapyloric botulinum toxin, gastric emptying procedures such as pyloroplasty, and gastric electrical stimulation. We will review these options in this article.