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Huang IH, Calder S, Gharibans AA, Schamberg G, Varghese C, Andrews CN, Tack J, O'Grady G. Meal effects on gastric bioelectrical activity utilizing body surface gastric mapping in healthy subjects. Neurogastroenterol Motil 2024:e14823. [PMID: 38764250 DOI: 10.1111/nmo.14823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/01/2024] [Accepted: 05/09/2024] [Indexed: 05/21/2024]
Abstract
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.
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Affiliation(s)
- I-Hsuan Huang
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Stefan Calder
- Alimetry Ltd, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Armen A Gharibans
- Alimetry Ltd, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Gabriel Schamberg
- Alimetry Ltd, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Christopher N Andrews
- Alimetry Ltd, Auckland, New Zealand
- Division of Gastroenterology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Greg O'Grady
- Alimetry Ltd, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
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Huang IH, Schol J, Calder S, Gharibans AA, Van den Houte K, Verheyden A, Broeders B, Carbone F, O'Grady G, Tack J. Effects of corticotropin-releasing hormone on gastric electrical activity and sensorimotor function in healthy volunteers: a double-blinded crossover study. Am J Physiol Gastrointest Liver Physiol 2024; 326:G622-G630. [PMID: 38375576 DOI: 10.1152/ajpgi.00298.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/06/2024] [Accepted: 02/15/2024] [Indexed: 02/21/2024]
Abstract
Biopsychosocial factors are associated with disorders of gut-brain interaction (DGBI) and exacerbate gastrointestinal symptoms. The mechanisms underlying pathophysiological alterations of stress remain unclear. Corticotropin-releasing hormone (CRH) is a central regulator of the hormonal stress response and has diverse impact on different organ systems. The aim of the present study was to investigate the effects of peripheral CRH infusion on meal-related gastrointestinal symptoms, gastric electrical activity, and gastric sensorimotor function in healthy volunteers (HVs). In a randomized, double-blinded, placebo-controlled, crossover study, we evaluated the effects of CRH on gastric motility and sensitivity. HVs were randomized to receive either peripheral-administered CRH (100 µg bolus + 1 µg/kg/h) or placebo (saline), followed by at least a 7-day washout period and assignment to the opposite treatment. Tests encompassed saliva samples, gastric-emptying (GE) testing, body surface gastric mapping (BSGM, Gastric Alimetry; Alimetry) to assess gastric myoelectrical activity with real-time symptom profiling, and a gastric barostat study to assess gastric sensitivity to distention and accommodation. Twenty HVs [13 women, mean age 29.2 ± 5.3 yr, body mass index (BMI) 23.3 ± 3.8 kg/m2] completed GE tests, of which 18 also underwent BSGM measurements during the GE tests. The GE half-time decreased significantly after CRH exposure (65.2 ± 17.4 vs. 78.8 ± 24.5 min, P = 0.02) with significantly increased gastric amplitude [49.7 (34.7-55.6) vs. 31.7 (25.7-51.0) µV, P < 0.01], saliva cortisol levels, and postprandial symptom severity. Eleven HVs also underwent gastric barostat studies on a separate day. However, the thresholds for discomfort during isobaric distensions, gastric compliance, and accommodation did not differ between CRH and placebo.NEW & NOTEWORTHY In healthy volunteers, peripheral corticotropin-releasing hormone (CRH) infusion accelerates gastric-emptying rate and increases postprandial gastric response, accompanied by a rise in symptoms, but does not alter gastric sensitivity or meal-induced accommodation. These findings underscore a significant link between stress and dyspeptic symptoms, with CRH playing a pivotal role in mediating these effects.
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Affiliation(s)
- I-Hsuan Huang
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Jolien Schol
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | | | | | - Karen Van den Houte
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Annelies Verheyden
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Bert Broeders
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Florencia Carbone
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - Greg O'Grady
- Alimetry, Ltd., Auckland, New Zealand
- Surgical and Translational Research Centre, The University of Auckland, Auckland, New Zealand
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
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Xu W, Wang T, Foong D, Schamberg G, Evennett N, Beban G, Gharibans A, Calder S, Daker C, Ho V, O'Grady G. Characterization of gastric dysfunction after fundoplication using body surface gastric mapping. J Gastrointest Surg 2024; 28:236-245. [PMID: 38445915 DOI: 10.1016/j.gassur.2023.12.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/09/2023] [Accepted: 12/22/2023] [Indexed: 03/07/2024]
Abstract
BACKGROUND Adverse gastric symptoms persist in up to 20% of fundoplication operations completed for gastroesophageal reflux disease, causing significant morbidity and driving the need for revisional procedures. Noninvasive techniques to assess the mechanisms of persistent postoperative symptoms are lacking. This study aimed to investigate gastric myoelectrical abnormalities and symptoms in patients after fundoplication using a novel noninvasive body surface gastric mapping (BSGM) device. METHODS Patients with a previous fundoplication operation and ongoing significant gastroduodenal symptoms and matched controls were included. BSGM using Gastric Alimetry (Alimetry Ltd) was employed, consisting of a high-resolution 64-channel array, validated symptom-logging application, and wearable reader. RESULTS A total of 16 patients with significant chronic symptoms after fundoplication were recruited, with 16 matched controls. Overall, 6 of 16 patients (37.5%) showed significant spectral abnormalities defined by unstable gastric myoelectrical activity (n = 2), abnormally high gastric frequencies (n = 3), or high gastric amplitudes (n = 1). Patients with spectral abnormalities had higher Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index scores than those of patients without spectral abnormalities (3.2 [range, 2.8-3.6] vs 2.3 [range, 2.2-2.8], respectively; P = .024). Moreover, 7 of 16 patients (43.8%) had BSGM test results suggestive of gut-brain axis contributions and without myoelectrical dysfunction. Increasing Principal Gastric Frequency Deviation and decreasing Rhythm Index scores were associated with symptom severity (r > .40; P < .05). CONCLUSION A significant number of patients with persistent postfundoplication symptoms displayed abnormal gastric function on BSGM testing, which correlated with symptom severity. Our findings advance the pathophysiologic understanding of postfundoplication disorders, which may inform diagnosis and patient selection for medical therapy and revisional procedures.
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Affiliation(s)
- William Xu
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Tim Wang
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Daphne Foong
- Alimetry Ltd, Auckland, New Zealand; School of Medicine, Western Sydney University, Penrith, Australia
| | - Gabe Schamberg
- Department of Surgery, University of Auckland, Auckland, New Zealand; Alimetry Ltd, Auckland, New Zealand
| | - Nicholas Evennett
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Grant Beban
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Armen Gharibans
- Alimetry Ltd, Auckland, New Zealand; Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Stefan Calder
- Alimetry Ltd, Auckland, New Zealand; Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Charlotte Daker
- Alimetry Ltd, Auckland, New Zealand; Department of Gastroenterology, North Shore Hospital, Auckland, New Zealand
| | - Vincent Ho
- School of Medicine, Western Sydney University, Penrith, Australia; Department of Gastroenterology and Hepatology, Campbelltown Hospital, Campbelltown, Australia
| | - Greg O'Grady
- Department of Surgery, University of Auckland, Auckland, New Zealand; Alimetry Ltd, Auckland, New Zealand; Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
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Du P, Maharjan A, Calder S, Schultz M, Schamberg G, Gharibans A, O'Grady G, Cakmak YO. Transcutaneous Auricular Vagus Nerve Stimulation Normalizes Induced Gastric Myoelectrical Dysrhythmias in Controls Assessed by Body-Surface Gastric Mapping. Neuromodulation 2024; 27:333-342. [PMID: 36997454 DOI: 10.1016/j.neurom.2023.02.078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 01/24/2023] [Accepted: 02/13/2023] [Indexed: 03/31/2023]
Abstract
OBJECTIVES Transcutaneous auricular vagus nerve stimulation (TaVNS) is a supplementary treatment for gastric symptoms resulting from dysrhythmias. The main objective of this study was to quantify the effects of 10, 40, and 80 Hz TaVNS and sham in healthy individuals in response to a 5-minute water-load (WL5) test. MATERIALS AND METHODS Eighteen healthy volunteers aged between 21 and 55 years (body mass index: 27.1 ± 3.2) were recruited. Each subject fasted for up to eight hours and participated in four 95-minute sessions, which consisted of 30 fasted baseline, 30 minutes TaVNS, WL5, and 30 minutes post-WL5. Heart rate variability was assessed using sternal electrocardiogram. Body-surface gastric mapping and bloating (/10) were recorded. One-way ANOVA with post hoc Tukey test was performed to test the difference between TaVNS protocols in terms of frequency, amplitude, bloating scores, root mean square of the successive differences (RMSSD), and stress index (SI). RESULTS On average, the subjects consumed 526 ± 160 mL of water, with volume ingested correlated to bloating (mean score 4.1 ± 1.8; r = 0.36, p = 0.029). In general, the reduction in frequency and rhythm stability during the post-WL5 period in sham was normalized by all three TaVNS protocols. Both 40- and 80-Hz protocols also caused increases in amplitude during the stim-only and/or post-WL5 periods. RMSSD increased during the 40-Hz protocol. SI increased during the 10-Hz protocol but decreased during the 40- and 80-Hz protocols. CONCLUSION TaVNS proved effective in normalizing gastric dysrhythmias by WL5 in healthy subjects by altering both parasympathetic and sympathetic pathways.
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Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Ashim Maharjan
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Stefan Calder
- Department of Surgery, The University of Auckland, Auckland, New Zealand; Alimetry Ltd, Auckland, New Zealand
| | - Michael Schultz
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | | | - Armen Gharibans
- Department of Surgery, The University of Auckland, Auckland, New Zealand; Alimetry Ltd, Auckland, New Zealand
| | - Gregory O'Grady
- Department of Surgery, The University of Auckland, Auckland, New Zealand; Alimetry Ltd, Auckland, New Zealand
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Wang WJ, Foong D, Calder S, Schamberg G, Varghese C, Tack J, Xu W, Daker C, Carson D, Waite S, Hayes T, Du P, Abell TL, Parkman HP, Huang IH, Fernandes V, Andrews CN, Gharibans AA, Ho V, O’Grady G. Gastric Alimetry Expands Patient Phenotyping in Gastroduodenal Disorders Compared with Gastric Emptying Scintigraphy. Am J Gastroenterol 2024; 119:331-341. [PMID: 37782524 PMCID: PMC10872929 DOI: 10.14309/ajg.0000000000002528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/04/2023] [Indexed: 10/03/2023]
Abstract
INTRODUCTION Gastric emptying testing (GET) assesses gastric motility, however, is nonspecific and insensitive for neuromuscular disorders. Gastric Alimetry (GA) is a new medical device combining noninvasive gastric electrophysiological mapping and validated symptom profiling. This study assessed patient-specific phenotyping using GA compared with GET. METHODS Patients with chronic gastroduodenal symptoms underwent simultaneous GET and GA, comprising a 30-minute baseline, 99m TC-labelled egg meal, and 4-hour postprandial recording. Results were referenced to normative ranges. Symptoms were profiled in the validated GA App and phenotyped using rule-based criteria based on their relationships to the meal and gastric activity: (i) sensorimotor, (ii) continuous, and (iii) other. RESULTS Seventy-five patients were assessed, 77% female. Motility abnormality detection rates were as follows: GET 22.7% (14 delayed, 3 rapid), GA spectral analysis 33.3% (14 low rhythm stability/low amplitude, 5 high amplitude, and 6 abnormal frequency), and combined yield 42.7%. In patients with normal spectral analysis, GA symptom phenotypes included sensorimotor 17% (where symptoms strongly paired with gastric amplitude, median r = 0.61), continuous 30%, and other 53%. GA phenotypes showed superior correlations with Gastroparesis Cardinal Symptom Index, Patient Assessment of Upper Gastrointestinal Symptom Severity Index, and anxiety scales, whereas Rome IV Criteria did not correlate with psychometric scores ( P > 0.05). Delayed emptying was not predictive of specific GA phenotypes. DISCUSSION GA improves patient phenotyping in chronic gastroduodenal disorders in the presence and absence of motility abnormalities with increased correlation with symptoms and psychometrics compared with gastric emptying status and Rome IV criteria. These findings have implications for the diagnostic profiling and personalized management of gastroduodenal disorders.
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Affiliation(s)
- William Jiaen Wang
- Gastrointestinal Motility Disorders Unit, Western Sydney University, Australia
- Department of Gastroenterology and Hepatology, Campbelltown Hospital, Australia
- Gastroenterology and Hepatology, Princess Alexandra Hospital, Australia
| | - Daphne Foong
- Gastrointestinal Motility Disorders Unit, Western Sydney University, Australia
| | - Stefan Calder
- Department of Surgery, Auckland City Hospital, New Zealand
- Auckland Bioengineering Institute, University of Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
| | - Gabriel Schamberg
- Department of Surgery, Auckland City Hospital, New Zealand
- Alimetry Ltd, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, Auckland City Hospital, New Zealand
| | - Jan Tack
- Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Belgium
| | - William Xu
- Department of Surgery, Auckland City Hospital, New Zealand
| | - Charlotte Daker
- Department of Gastroenterology, North Shore Hospital, Auckland, New Zealand
| | - Daniel Carson
- Department of Surgery, Auckland City Hospital, New Zealand
| | | | - Thomas Hayes
- Department of Surgery, Auckland City Hospital, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | - Thomas L. Abell
- Division of Gastroenterology, University of Louisville, KY, USA
| | - Henry P. Parkman
- Gastroenterology Section, Department of Medicine, Lewis Katz School of Medicine, Temple University, USA
| | - I-Hsuan Huang
- Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven, Belgium
| | | | | | - Armen A. Gharibans
- Department of Surgery, Auckland City Hospital, New Zealand
- Auckland Bioengineering Institute, University of Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
| | - Vincent Ho
- Gastrointestinal Motility Disorders Unit, Western Sydney University, Australia
- Department of Gastroenterology and Hepatology, Campbelltown Hospital, Australia
| | - Greg O’Grady
- Department of Surgery, Auckland City Hospital, New Zealand
- Auckland Bioengineering Institute, University of Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
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Andrews PLR, Golding JF, Sanger GJ. An assessment of the effects of neurokinin 1 receptor antagonism against nausea and vomiting: Relative efficacy, sites of action and lessons for future drug development. Br J Clin Pharmacol 2023; 89:3468-3490. [PMID: 37452618 DOI: 10.1111/bcp.15852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
A broad-spectrum anti-vomiting effect of neurokinin1 receptor antagonists (NK1 RA), shown in pre-clinical animal studies, has been supported by a more limited range of clinical studies in different indications. However, this review suggests that compared with vomiting, the self-reported sensation of nausea is less affected or possibly unaffected (depending on the stimulus) by NK1 receptor antagonism, a common finding for anti-emetics. The stimulus-independent effects of NK1 RAs against vomiting are explicable by actions within the central pattern generator (ventral brainstem) and the nucleus tractus solitarius (NTS; dorsal brainstem), with additional effects on vagal afferent activity for certain stimuli (e.g., highly emetogenic chemotherapy). The central pattern generator and NTS neurones are multifunctional so the notable lack of obvious effects of NK1 RAs on other reflexes mediated by the same neurones suggests that their anti-vomiting action is dependent on the activation state of the pathway leading to vomiting. Nausea requires activation of cerebral pathways by projection of information from the NTS. Although NK1 receptors are present in cerebral nuclei implicated in nausea, and imaging studies show very high receptor occupancy at clinically used doses, the variable or limited ability of NK1 RAs to inhibit nausea emphasizes: (i) our inadequate understanding of the mechanisms of nausea; and (ii) that classification of a drug as an anti-emetic may give a false impression of efficacy against nausea vs. vomiting. We discuss the potential mechanisms for the differential efficacy of NK1 RA and the implications for future development of drugs that can effectively treat nausea, an area of unmet clinical need.
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Affiliation(s)
- Paul L R Andrews
- Division of Biomedical Sciences, St George's University of London, London, UK
| | | | - Gareth J Sanger
- Blizard Institute, Faculty of Medicine and Dentistry, Queen Mary University of London, London, UK
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Foong D, Calder S, Varghese C, Schamberg G, Xu W, Daker C, Ho V, Andrews CN, Gharibans AA, O’Grady G. Gastric Alimetry ® Test Interpretation in Gastroduodenal Disorders: Review and Recommendations. J Clin Med 2023; 12:6436. [PMID: 37892572 PMCID: PMC10607701 DOI: 10.3390/jcm12206436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/04/2023] [Accepted: 10/08/2023] [Indexed: 10/29/2023] Open
Abstract
Chronic gastroduodenal symptoms are prevalent worldwide, and there is a need for new diagnostic and treatment approaches. Several overlapping processes may contribute to these symptoms, including gastric dysmotility, hypersensitivity, gut-brain axis disorders, gastric outflow resistance, and duodenal inflammation. Gastric Alimetry® (Alimetry, New Zealand) is a non-invasive test for evaluating gastric function that combines body surface gastric mapping (high-resolution electrophysiology) with validated symptom profiling. Together, these complementary data streams enable important new clinical insights into gastric disorders and their symptom correlations, with emerging therapeutic implications. A comprehensive database has been established, currently comprising > 2000 Gastric Alimetry tests, including both controls and patients with various gastroduodenal disorders. From studies employing this database, this paper presents a systematic methodology for Gastric Alimetry test interpretation, together with an extensive supporting literature review. Reporting is grouped into four sections: Test Quality, Spectral Analysis, Symptoms, and Conclusions. This review compiles, assesses, and evaluates each of these aspects of test assessment, with discussion of relevant evidence, example cases, limitations, and areas for future work. The resultant interpretation methodology is recommended for use in clinical practice and research to assist clinicians in their use of Gastric Alimetry as a diagnostic aid and is expected to continue to evolve with further development.
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Affiliation(s)
- Daphne Foong
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
| | - Stefan Calder
- Department of Surgery, Auckland City Hospital, Auckland 1023, New Zealand
- Alimetry Ltd., Auckland 1010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - Chris Varghese
- Department of Surgery, Auckland City Hospital, Auckland 1023, New Zealand
| | - Gabriel Schamberg
- Alimetry Ltd., Auckland 1010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - William Xu
- Department of Surgery, Auckland City Hospital, Auckland 1023, New Zealand
| | - Charlotte Daker
- Department of Gastroenterology, North Shore Hospital, Auckland 0620, New Zealand
| | - Vincent Ho
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia
- Department of Gastroenterology and Hepatology, Campbelltown Hospital, Sydney, NSW 2560, Australia
| | - Christopher N. Andrews
- Division of Gastroenterology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Armen A. Gharibans
- Department of Surgery, Auckland City Hospital, Auckland 1023, New Zealand
- Alimetry Ltd., Auckland 1010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - Greg O’Grady
- Department of Surgery, Auckland City Hospital, Auckland 1023, New Zealand
- Alimetry Ltd., Auckland 1010, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
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O'Grady G, Varghese C, Schamberg G, Calder S, Du P, Xu W, Tack J, Daker C, Mousa H, Abell TL, Parkman HP, Ho V, Bradshaw LA, Hobson A, Andrews CN, Gharibans AA. Principles and clinical methods of body surface gastric mapping: Technical review. Neurogastroenterol Motil 2023; 35:e14556. [PMID: 36989183 PMCID: PMC10524901 DOI: 10.1111/nmo.14556] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/29/2023] [Accepted: 02/12/2023] [Indexed: 03/30/2023]
Abstract
BACKGROUND AND PURPOSE Chronic gastric symptoms are common, however differentiating specific contributing mechanisms in individual patients remains challenging. Abnormal gastric motility is present in a significant subgroup, but reliable methods for assessing gastric motor function in clinical practice are lacking. Body surface gastric mapping (BSGM) is a new diagnostic aid, employs multi-electrode arrays to measure and map gastric myoelectrical activity non-invasively in high resolution. Clinical adoption of BSGM is currently expanding following studies demonstrating the ability to achieve specific patient subgrouping, and subsequent regulatory clearances. An international working group was formed in order to standardize clinical BSGM methods, encompassing a technical group developing BSGM methods and a clinical advisory group. The working group performed a technical literature review and synthesis focusing on the rationale, principles, methods, and clinical applications of BSGM, with secondary review by the clinical group. The principles and validation of BSGM were evaluated, including key advances achieved over legacy electrogastrography (EGG). Methods for BSGM were reviewed, including device design considerations, patient preparation, test conduct, and data processing steps. Recent advances in BSGM test metrics and reference intervals are discussed, including four novel metrics, being the 'principal gastric frequency', BMI-adjusted amplitude, Gastric Alimetry Rhythm Index™, and fed: fasted amplitude ratio. An additional essential element of BSGM has been the introduction of validated digital tools for standardized symptom profiling, performed simultaneously during testing. Specific phenotypes identifiable by BSGM and the associated symptom profiles were codified with reference to pathophysiology. Finally, knowledge gaps and priority areas for future BSGM research were also identified by the working group.
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Affiliation(s)
- Gregory O'Grady
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Gabriel Schamberg
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
| | | | - Peng Du
- Alimetry Ltd, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - William Xu
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Jan Tack
- Department of Gastroenterology, University Hospitals, Leuven, Belgium
| | | | - Hayat Mousa
- Division of Gastroenterology, Lustgarten Motility Center, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Thomas L Abell
- Division of Gastroenterology, Hepatology and Nutrition, University of Louisville, Louisville, Kentucky, USA
| | - Henry P Parkman
- Department of Medicine, Temple University Hospital, Philadelphia, Pennsylvania, USA
| | - Vincent Ho
- Western Sydney University, Sydney, New South Wales, Australia
| | | | | | - Christopher N Andrews
- Division of Gastroenterology and Hepatology, University of Calgary, Calgary, Alberta, Canada
| | - Armen A Gharibans
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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Makwana R, Sanger GJ. Characterization of rat gastric myogenic contractions and modulation by oxytocin and arginine-vasopressin. Eur J Pharmacol 2023; 955:175906. [PMID: 37429518 DOI: 10.1016/j.ejphar.2023.175906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/12/2023]
Abstract
BACKGROUND Interstitial cells of Cajal generate slow wave gastric electrical activity, initiating spontaneous muscle contractions. This becomes dysrhythmic during nausea when [Arg8]-vasopressin (AVP) is also released. In human stomach AVP increased spontaneous contraction activity and muscle tone, not neuronally-mediated contractions. Rodents cannot vomit, releasing the related hormone, oxytocin (OT) instead. We hypothesised that rat stomach would behave differently. EXPERIMENTAL APPROACH Spontaneous and electrically-evoked (EFS) contractions were measured in rat forestomach and antrum circular muscle. Custom software defined spontaneous contractions by analysing eight motility parameters. RESULTS The forestomach was quiescent. Irregular antrum contractions became regular adjacent to the pylorus (1.7 ± 0.4 mN; 1.2 ± 0.1 contractions/min, n = 12). These were unaffected by tetrodotoxin (10-6 M), atropine (10-6 M) and L-NAME (3 × 10-4 M). In both regions, AVP (pEC50∼9.0) and OT (∼0.5 log10-unit less potent) caused contraction (greater in antrum), competitively antagonized by, respectively, SR49059 (pKB∼9.5) and L371257 (pKB∼9.0), reduced by tetrodotoxin but unaffected by atropine. In the antrum, AVP and OT (∼2 log10-units less potent/efficacious) regularized and increased spontaneous contraction amplitude, frequency, rates of contraction/decay. In both regions, EFS-evoked contractions, abolished by atropine/tetrodotoxin, were reduced by AVP and OT, with AVP more potent and efficacious, particularly in forestomach. CONCLUSION Irregular spontaneous contractions of gastric antrum suggest variable ICC-muscle coupling. AVP and less potently, OT, enhanced frequency and force of contractions via V1A and OT receptors. Compared with human, differences in contraction regularity, potency and ability of AVP/OT to affect neuronal function suggests caution when using rat stomach to model ICC functions and nauseagenic stimuli.
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Affiliation(s)
- Raj Makwana
- Blizard Institute, Queen Mary University of London, UK
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10
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Schamberg G, Calder S, Varghese C, Xu W, Wang WJ, Ho V, Daker C, Andrews CN, O'Grady G, Gharibans AA. Comparison of Gastric Alimetry ® body surface gastric mapping versus electrogastrography spectral analysis. Sci Rep 2023; 13:14987. [PMID: 37696955 PMCID: PMC10495352 DOI: 10.1038/s41598-023-41645-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023] Open
Abstract
Electrogastrography (EGG) non-invasively evaluates gastric motility but is viewed as lacking clinical utility. Gastric Alimetry® is a new diagnostic test that combines high-resolution body surface gastric mapping (BSGM) with validated symptom profiling, with the goal of overcoming EGG's limitations. This study directly compared EGG and BSGM to define performance differences in spectral analysis. Comparisons between Gastric Alimetry BSGM and EGG were conducted by protocolized retrospective evaluation of 178 subjects [110 controls; 68 nausea and vomiting (NVS) and/or type 1 diabetes (T1D)]. Comparisons followed standard methodologies for each test (pre-processing, post-processing, analysis), with statistical evaluations for group-level differences, symptom correlations, and patient-level classifications. BSGM showed substantially tighter frequency ranges vs EGG in controls. Both tests detected rhythm instability in NVS, but EGG showed opposite frequency effects in T1D. BSGM showed an 8× increase in the number of significant correlations with symptoms. BSGM accuracy for patient-level classification was 0.78 for patients vs controls and 0.96 as compared to blinded consensus panel; EGG accuracy was 0.54 and 0.43. EGG detected group-level differences in patients, but lacked symptom correlations and showed poor accuracy for patient-level classification, explaining EGG's limited clinical utility. BSGM demonstrated substantial performance improvements across all domains.
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Affiliation(s)
- Gabriel Schamberg
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
| | - Stefan Calder
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - William Xu
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - William Jiaen Wang
- School of Medicine, Western Sydney University, Sydney, Australia
- Department of Gastroenterology and Hepatology, Campbelltown Hospital, Sydney, Australia
- Department of Gastroenterology and Hepatology, Townsville University Hospital, Townsville, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia
| | - Vincent Ho
- School of Medicine, Western Sydney University, Sydney, Australia
- Department of Gastroenterology and Hepatology, Campbelltown Hospital, Sydney, Australia
| | - Charlotte Daker
- Department of Gastroenterology, North Shore Hospital, Auckland, New Zealand
| | | | - Greg O'Grady
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry Ltd, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Armen A Gharibans
- Department of Surgery, The University of Auckland, Auckland, New Zealand.
- Alimetry Ltd, Auckland, New Zealand.
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
- Perelman School of Medicine, University of Pennsylvania, Pennsylvania, United States.
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11
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Di Natale MR, Athavale ON, Wang X, Du P, Cheng LK, Liu Z, Furness JB. Functional and anatomical gastric regions and their relations to motility control. Neurogastroenterol Motil 2023; 35:e14560. [PMID: 36912719 DOI: 10.1111/nmo.14560] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/12/2023] [Accepted: 02/24/2023] [Indexed: 03/14/2023]
Abstract
The common occurrence of gastric disorders, the accelerating emphasis on the role of the gut-brain axis, and development of realistic, predictive models of gastric function, all place emphasis on increasing understanding of the stomach and its control. However, the ways that regions of the stomach have been described anatomically, physiologically, and histologically do not align well. Mammalian single compartment stomachs can be considered as having four anatomical regions fundus, corpus, antrum, and pyloric sphincter. Functional regions are the proximal stomach, primarily concerned with adjusting gastric volume, the distal stomach, primarily involved in churning and propelling the content, and the pyloric sphincter that regulates passage of chyme into the duodenum. The proximal stomach extends from the dome of the fundus to a circumferential band where propulsive waves commence (slow waves of the pacemaker region), and the distal stomach consists of the pacemaker region and the more distal regions that are traversed by waves of excitation, that travel as far as the pyloric sphincter. Thus, the proximal stomach includes the fundus and different extents of the corpus, whereas the distal stomach consists of the remainder of the corpus and the antrum. The distributions of aglandular regions and of specialized glands, such as oxyntic glands, differ vastly between species and, across species, have little or no relation to anatomical or functional regions. It is hoped that this review helps to clarify nomenclature that defines gastric regions that will provide an improved basis for drawing conclusions for different investigations of the stomach.
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Affiliation(s)
- Madeleine R Di Natale
- Department of Anatomy & Physiology, University of Melbourne, Parkville, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Omkar N Athavale
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Xiaokai Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Zhongming Liu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - John B Furness
- Department of Anatomy & Physiology, University of Melbourne, Parkville, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
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12
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Aghababaie Z, Wang THH, Nisbet LA, Matthee A, Dowrick J, Sands GB, Paskaranandavadivel N, Cheng LK, O'Grady G, Angeli-Gordon TR. Anaesthesia by intravenous propofol reduces the incidence of intra-operative gastric electrical slow-wave dysrhythmias compared to isoflurane. Sci Rep 2023; 13:11824. [PMID: 37479717 PMCID: PMC10362009 DOI: 10.1038/s41598-023-38612-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023] Open
Abstract
Gastric motility is coordinated by bioelectrical slow-wave activity, and abnormal electrical dysrhythmias have been associated with nausea and vomiting. Studies have often been conducted under general anaesthesia, while the impact of general anaesthesia on slow-wave activity has not been studied. Clinical studies have shown that propofol anaesthesia reduces postoperative nausea and vomiting (PONV) compared with isoflurane, while the underlying mechanisms remain unclear. In this study, we investigated the effects of two anaesthetic drugs, intravenous (IV) propofol and volatile isoflurane, on slow-wave activity. In vivo experiments were performed in female weaner pigs (n = 24). Zolazepam and tiletamine were used to induce general anaesthesia, which was maintained using either IV propofol (n = 12) or isoflurane (n = 12). High-resolution electrical mapping of slow-wave activity was performed. Slow-wave dysrhythmias occurred less often in the propofol group, both in the duration of the recorded period that was dysrhythmic (propofol 14 ± 26%, isoflurane 43 ± 39%, P = 0.043 (Mann-Whitney U test)), and in a case-by-case basis (propofol 3/12, isoflurane 8/12, P = 0.015 (Chi-squared test)). Slow-wave amplitude was similar, while velocity and frequency were higher in the propofol group than the isoflurane group (P < 0.001 (Student's t-test)). This study presents a potential physiological biomarker linked to recent observations of reduced PONV with IV propofol. The results suggest that propofol is a more suitable anaesthetic for studying slow-wave patterns in vivo.
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Affiliation(s)
- Zahra Aghababaie
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Tim Hsu-Han Wang
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Linley A Nisbet
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Ashton Matthee
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Jarrah Dowrick
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Gregory B Sands
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | | | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Gregory O'Grady
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Timothy R Angeli-Gordon
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand.
- Department of Surgery, University of Auckland, Auckland, New Zealand.
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13
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Varghese C, Schamberg G, Calder S, Waite S, Carson D, Foong D, Wang WJ, Ho V, Woodhead J, Daker C, Xu W, Du P, Abell TL, Parkman HP, Tack J, Andrews CN, O'Grady G, Gharibans AA. Normative Values for Body Surface Gastric Mapping Evaluations of Gastric Motility Using Gastric Alimetry: Spectral Analysis. Am J Gastroenterol 2023; 118:1047-1057. [PMID: 36534985 DOI: 10.14309/ajg.0000000000002077] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/06/2022] [Indexed: 06/02/2023]
Abstract
INTRODUCTION Body surface gastric mapping (BSGM) is a new noninvasive test of gastric function. BSGM offers several novel and improved biomarkers of gastric function capable of differentiating patients with overlapping symptom profiles. The aim of this study was to define normative reference intervals for BSGM spectral metrics in a population of healthy controls. METHODS BSGM was performed in healthy controls using Gastric Alimetry (Alimetry, New Zealand) comprising a stretchable high-resolution array (8 × 8 electrodes; 196 cm 2 ), wearable Reader, and validated symptom-logging App. The evaluation encompassed a fasting baseline (30 minutes), 482 kCal meal, and 4-hour postprandial recording. Normative reference intervals were calculated for BSGM metrics including the Principal Gastric Frequency, Gastric Alimetry Rhythm Index (a measure of the concentration of power in the gastric frequency band over time), body mass index (BMI)-adjusted amplitude (μV), and fed:fasted amplitude ratio. Data were reported as median and reference interval (5th and/or 95th percentiles). RESULTS A total of 110 subjects (55% female, median age 32 years [interquartile range 24-50], median BMI 23.8 kg/m 2 [interquartile range 21.4-26.9]) were included. The median Principal Gastric Frequency was 3.04 cycles per minute; reference interval: 2.65-3.35 cycles per minute. The median Gastric Alimetry Rhythm Index was 0.50; reference interval: ≥0.25. The median BMI-adjusted amplitude was 37.6 μV; reference interval: 20-70 μV. The median fed:fasted amplitude ratio was 1.85; reference interval ≥1.08. A higher BMI was associated with a shorter meal-response duration ( P = 0.014). DISCUSSION This study provides normative reference intervals for BSGM spectral data to inform diagnostic interpretations of abnormal gastric function.
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Affiliation(s)
- Chris Varghese
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Gabriel Schamberg
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry, Auckland, New Zealand
| | - Stefan Calder
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry, Auckland, New Zealand
| | | | - Daniel Carson
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | | | | | - Vincent Ho
- Western Sydney University, Sydney, Australia
| | | | | | - William Xu
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Peng Du
- Alimetry, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Thomas L Abell
- Division of Gastroenterology, Hepatology and Nutrition, University of Louisville, Kentucky, USA
| | - Henry P Parkman
- Department of Medicine, Temple University Hospital, Philadelphia, Pennsylvania, USA
| | - Jan Tack
- Department of Gastroenterology, University Hospitals, Leuven, Belgium
| | | | - Gregory O'Grady
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Armen A Gharibans
- Department of Surgery, The University of Auckland, Auckland, New Zealand
- Alimetry, Auckland, New Zealand
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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14
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Wang WJ, Foong D, Calder S, Schamberg G, Varghese C, Tack J, Xu W, Daker C, Carson D, Waite S, Hayes T, Du P, Abell TL, Parkman HP, Huang IH, Fernandes V, Andrews CN, Gharibans AA, Ho V, O'Grady G. Gastric Alimetry ® improves patient phenotyping in gastroduodenal disorders compared to gastric emptying scintigraphy alone. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.18.23290134. [PMID: 37292604 PMCID: PMC10246136 DOI: 10.1101/2023.05.18.23290134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Objectives Gastric emptying testing (GET) assesses gastric motility, however is non-specific and insensitive for neuromuscular disorders. Gastric Alimetry® (GA) is a new medical device combining non-invasive gastric electrophysiological mapping and validated symptom profiling. This study assessed patient-specific phenotyping using GA compared to GET. Methods Patients with chronic gastroduodenal symptoms underwent simultaneous GET and GA, comprising a 30-minute baseline, 99m TC-labelled egg meal, and 4-hour postprandial recording. Results were referenced to normative ranges. Symptoms were profiled in the validated GA App and phenotyped using rule-based criteria based on their relationships to the meal and gastric activity: i) sensorimotor; ii) continuous; and iii) other. Results 75 patients were assessed; 77% female. Motility abnormality detection rates were: GET 22.7% (14 delayed, 3 rapid); GA spectral analysis 33.3% (14 low rhythm stability / low amplitude; 5 high amplitude; 6 abnormal frequency); combined yield 42.7%. In patients with normal spectral analysis, GA symptom phenotypes included: sensorimotor 17% (where symptoms strongly paired with gastric amplitude; median r=0.61); continuous 30%; other 53%. GA phenotypes showed superior correlations with GCSI, PAGI-SYM, and anxiety scales, whereas Rome IV Criteria did not correlate with psychometric scores (p>0.05). Delayed emptying was not predictive of specific GA phenotypes. Conclusions GA improves patient phenotyping in chronic gastroduodenal disorders in the presence and absence of motility abnormalities with improved correlation with symptoms and psychometrics compared to gastric emptying status and Rome IV criteria. These findings have implications for the diagnostic profiling and personalized management of gastroduodenal disorders. Study Highlights 1) WHAT IS KNOWN Chronic gastroduodenal symptoms are common, costly and greatly impact on quality of lifeThere is a poor correlation between gastric emptying testing (GET) and symptomsGastric Alimetry® is a new medical device combining non-invasive gastric electrophysiological mapping and validated symptom profiling 2) WHAT IS NEW HERE Gastric Alimetry generates a 1.5x higher yield for motility abnormalities than GETWith symptom profiling, Gastric Alimetry identified 2.7x more specific patient categories than GETGastric Alimetry improves clinical phenotyping, with improved correlation with symptoms and psychometrics compared to GET.
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15
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Jones KL, Rayner CK, Horowitz M. Editorial: empirical pharmacological management of gastroparesis-a cautionary tale. Aliment Pharmacol Ther 2023; 57:1178-1179. [PMID: 37094319 DOI: 10.1111/apt.17499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Affiliation(s)
- Karen L Jones
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Christopher K Rayner
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia
- Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Michael Horowitz
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide, South Australia, Australia
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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16
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Schamberg G, Varghese C, Calder S, Waite S, Erickson J, O'Grady G, Gharibans AA. Revised spectral metrics for body surface measurements of gastric electrophysiology. Neurogastroenterol Motil 2023; 35:e14491. [PMID: 36409749 DOI: 10.1111/nmo.14491] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/17/2022] [Accepted: 10/21/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Electrogastrography (EGG) non-invasively evaluates gastric function but has not achieved common clinical adoption due to several technical limitations. Body Surface Gastric Mapping (BSGM) has been introduced to overcome these limitations, but pitfalls in traditional metrics used to analyze spectral data remain unaddressed. This study critically evaluates five traditional EGG metrics and introduces improved BSGM spectral metrics, with validation in a large cohort. METHODS Pitfalls in five EGG metrics were assessed (dominant frequency, percentage time normogastria, amplitude, power ratio, and instability coefficient), leading to four revised BSGM spectral metrics. Traditional and revised metrics were compared to validate performance using a standardized 100-subject database of BSGM tests (30 min baseline; 4-h postprandial) recorded using Gastric Alimetry® (Alimetry). KEY RESULTS BMI and amplitude were highly correlated (r = -0.57, p < 0.001). We applied a conservative BMI correction to obtain a BMI-adjusted amplitude metric (r = -0.21, p = 0.037). Instability coefficient was highly correlated with both dominant frequency (r = -0.44, p < 0.001), and percent bradygastria (r = 0.85, p < 0.001), in part due to misclassification of low frequency transients as gastric activity. This was corrected by introducing distinct gastric frequency and stability metrics (Principal Gastric Frequency and Gastric Alimetry Rhythm Index (GA-RI)TM ) that were uncorrelated (r = 0.14, p = 0.314). Only 28% of subjects showed a maximal averaged amplitude within the first postprandial hour. Calculating Fed:Fasted Amplitude Ratio over a 4-h postprandial window yielded a median increase of 0.31 (IQR 0-0.64) above the traditional ratio. CONCLUSIONS & INFERENCES The revised metrics resolve critical pitfalls impairing the performance of traditional EGG, and should be applied in future BSGM spectral analyses.
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Affiliation(s)
- Gabriel Schamberg
- Alimetry Ltd, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Stefan Calder
- Alimetry Ltd, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
| | | | | | - Greg O'Grady
- Alimetry Ltd, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Armen A Gharibans
- Alimetry Ltd, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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17
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Tomaselli L, Sciullo M, Fulton S, Yates BJ, Fisher LE, Ventura V, Horn CC. Anesthesia suppresses gastric myoelectric power in the ferret. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529745. [PMID: 36865110 PMCID: PMC9980102 DOI: 10.1101/2023.02.23.529745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
BACKGROUND Gastrointestinal myoelectric signals have been the focus of extensive research; although it is unclear how general anesthesia affects these signals, studies have often been conducted under general anesthesia. Here, we explore this issue directly by recording gastric myoelectric signals during awake and anesthetized states in the ferret and also explore the contribution of behavioral movement to observed changes in signal power. METHODS Ferrets were surgically implanted with electrodes to record gastric myoelectric activity from the serosal surface of the stomach, and, following recovery, were tested in awake and isoflurane-anesthetized conditions. Video recordings were also analyzed during awake experiments to compare myoelectric activity during behavioral movement and rest. KEY RESULTS A significant decrease in gastric myoelectric signal power was detected under isoflurane anesthesia compared to the awake condition. Moreover, a detailed analysis of the awake recordings indicates that behavioral movement is associated with increased signal power compared to rest. CONCLUSIONS & INFERENCES These results suggest that both general anesthesia and behavioral movement can affect the amplitude of gastric myoelectric. In summary, caution should be taken in studying myoelectric data collected under anesthesia. Further, behavioral movement could have an important modulatory role on these signals, affecting their interpretation in clinical settings.
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18
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Gharibans AA, Hayes TCL, Carson DA, Calder S, Varghese C, Du P, Yarmut Y, Waite S, Keane C, Woodhead JST, Andrews CN, O'Grady G. A novel scalable electrode array and system for non-invasively assessing gastric function using flexible electronics. Neurogastroenterol Motil 2023; 35:e14418. [PMID: 35699340 PMCID: PMC10078595 DOI: 10.1111/nmo.14418] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/29/2022] [Accepted: 05/05/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Disorders of gastric function are highly prevalent, but diagnosis often remains symptom-based and inconclusive. Body surface gastric mapping is an emerging diagnostic solution, but current approaches lack scalability and are cumbersome and clinically impractical. We present a novel scalable system for non-invasively mapping gastric electrophysiology in high-resolution (HR) at the body surface. METHODS The system comprises a custom-designed stretchable high-resolution "peel-and-stick" sensor array (8 × 8 pre-gelled Ag/AgCl electrodes at 2 cm spacing; area 225 cm2 ), wearable data logger with custom electronics incorporating bioamplifier chips, accelerometer and Bluetooth synchronized in real-time to an App with cloud connectivity. Automated algorithms filter and extract HR biomarkers including propagation (phase) mapping. The system was tested in a cohort of 24 healthy subjects to define reliability and characterize features of normal gastric activity (30 m fasting, standardized meal, and 4 h postprandial). KEY RESULTS Gastric mapping was successfully achieved non-invasively in all cases (16 male; 8 female; aged 20-73 years; BMI 24.2 ± 3.5). In all subjects, gastric electrophysiology and meal responses were successfully captured and quantified non-invasively (mean frequency 2.9 ± 0.3 cycles per minute; peak amplitude at mean 60 m postprandially with return to baseline in <4 h). Spatiotemporal mapping showed regular and consistent wave activity of mean direction 182.7° ± 73 (74.7% antegrade, 7.8% retrograde, 17.5% indeterminate). CONCLUSIONS AND INFERENCES BSGM is a new diagnostic tool for assessing gastric function that is scalable and ready for clinical applications, offering several biomarkers that are improved or new to gastroenterology practice.
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Affiliation(s)
- Armen A Gharibans
- Department of Surgery, University of Auckland, Auckland, New Zealand.,Alimetry Ltd, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Tommy C L Hayes
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Daniel A Carson
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | | | - Chris Varghese
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Peng Du
- Alimetry Ltd, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | | | - Celia Keane
- Department of Surgery, University of Auckland, Auckland, New Zealand.,Alimetry Ltd, Auckland, New Zealand
| | - Jonathan S T Woodhead
- Alimetry Ltd, Auckland, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
| | - Christopher N Andrews
- Alimetry Ltd, Auckland, New Zealand.,Department of Medicine, University of Calgary, NB Calgary, Alberta, Canada
| | - Greg O'Grady
- Department of Surgery, University of Auckland, Auckland, New Zealand.,Alimetry Ltd, Auckland, New Zealand
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19
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Gaskell SK, Burgell R, Wiklendt L, Dinning PG, Costa RJS. Impact of exercise duration on gastrointestinal function and symptoms. J Appl Physiol (1985) 2023; 134:160-171. [PMID: 36476157 DOI: 10.1152/japplphysiol.00393.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The study aimed to determine the impact of exercise duration on gastrointestinal functional responses and gastrointestinal symptoms (GISs) in response to differing exercise durations. Endurance runners (n = 16) completed three trials on separate occasions, randomized to 1 h (1-H), 2 h (2-H), and 3 h (3-H) of running at 60% V̇o2max in temperate ambient temperature. Orocecal transit time (OCTT) was determined by lactulose challenge, with concomitant breath hydrogen (H2) determination. Gastric slow wave activity was recorded using cutaneous electrogastrography (cEGG) before and after exertion. GIS was determined using a modified visual analog scale (mVAS). OCTT response was classified as very slow on all trials (∼93-101 min) with no trial difference observed (P = 0.895). Bradygastria increased postexercise on all trials (means ± SD: 1-H: 10.9 ± 11.7%, 2-H: 6.2 ± 9.8%, and 3-H: 13.2 ± 21.4%; P < 0.05). A reduction in the normal gastric slow wave activity (2-4 cycles/min) was observed postexercise on 1-H only (-10.8 ± 17.6%; P = 0.039). GIS incidence and gut discomfort was higher on 2-H (81% and 12 counts) and 3-H (81% and 18 counts), compared with 1-H (69% and 6 counts) (P = 0.038 and P = 0.006, respectively). Severity of gut discomfort, total-GIS, upper-GIS, and lower-GIS increased during exercise on all trials (P < 0.05). Steady-state exercise in temperate ambient conditions for 1 h, 2 h, and 3 h instigates perturbations in gastric slow wave activity compared with rest and hampers OCTT, potentially explaining the incidence and severity on exercise-associated GIS.NEW & NOTEWORTHY Exercise stress per se appears to instigate perturbations to gastric myoelectrical activity, resulting in an increase in bradygastria frequency, inferring a reduction in gastric motility. The perturbations to gastrointestinal functional responses instigated by exercise per se, likely contribute to the high incidence and severity level of exercise-associated gastrointestinal symptoms. Cutaneous electrogastrography is not commonly used in exercise gastroenterology research, however, may be a useful aid in providing an overall depiction of gastrointestinal function. Particularly relating to gastrointestinal motility and concerning gastroparesis.
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Affiliation(s)
- Stephanie K Gaskell
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Rebecca Burgell
- Medicine, Nursing and Health Sciences, Monash University, Prahan, Victoria, Australia.,Department of Gastroenterology, Alfred Health, Prahan, Victoria, Australia
| | - Lukasz Wiklendt
- Department of Surgery, College of Medicine and Public Health, The Flinders University, Bedford Park, South Australia, Australia
| | - Phil G Dinning
- Department of Surgery, College of Medicine and Public Health, The Flinders University, Bedford Park, South Australia, Australia.,Flinders Medical Centre, Bedford Park, South Australia, Australia
| | - Ricardo J S Costa
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
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20
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Aghababaie Z, O'Grady G, Nisbet LA, Modesto AE, Chan CHA, Matthee A, Amirapu S, Beyder A, Farrugia G, Asirvatham SJ, Sands GB, Paskaranandavadivel N, Cheng LK, Angeli-Gordon TR. Localized bioelectrical conduction block from radiofrequency gastric ablation persists after healing: safety and feasibility in a recovery model. Am J Physiol Gastrointest Liver Physiol 2022; 323:G640-G652. [PMID: 36255716 PMCID: PMC9744642 DOI: 10.1152/ajpgi.00116.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/27/2022] [Accepted: 10/13/2022] [Indexed: 01/31/2023]
Abstract
Gastric ablation has demonstrated potential to induce conduction blocks and correct abnormal electrical activity (i.e., ectopic slow-wave propagation) in acute, intraoperative in vivo studies. This study aimed to evaluate the safety and feasibility of gastric ablation to modulate slow-wave conduction after 2 wk of healing. Chronic in vivo experiments were performed in weaner pigs (n = 6). Animals were randomly divided into two groups: sham-ablation (n = 3, control group; no power delivery, room temperature, 5 s/point) and radiofrequency (RF) ablation (n = 3; temperature-control mode, 65°C, 5 s/point). In the initial surgery, high-resolution serosal electrical mapping (16 × 16 electrodes; 6 × 6 cm) was performed to define the baseline slow-wave activation profile. Ablation (sham/RF) was then performed in the mid-corpus, in a line around the circumferential axis of the stomach, followed by acute postablation mapping. All animals recovered from the procedure, with no sign of perforation or other complications. Two weeks later, intraoperative high-resolution mapping was repeated. High-resolution mapping showed that ablation successfully induced sustained conduction blocks in all cases in the RF-ablation group at both the acute and 2 wk time points, whereas all sham-controls had no conduction block. Histological and immunohistochemical evaluation showed that after 2 wk of healing, the lesions were in the inflammation and early proliferation phase, and interstitial cells of Cajal (ICC) were depleted and/or deformed within the ablation lesions. This safety and feasibility study demonstrates that gastric ablation can safely and effectively induce a sustained localized conduction block in the stomach without disrupting the surrounding slow-wave conduction capability.NEW & NOTEWORTHY Ablation has recently emerged as a tool for modulating gastric electrical activation and may hold interventional potential for disorders of gastric function. However, previous studies have been limited to the acute intraoperative setting. This study now presents the safety of gastric ablation after postsurgical recovery and healing. Localized electrical conduction blocks created by ablation remained after 2 wk of healing, and no perforation or other complications were observed over the postsurgical period.
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Affiliation(s)
- Zahra Aghababaie
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Gregory O'Grady
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Linley A Nisbet
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Andre E Modesto
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | | | - Ashton Matthee
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Satya Amirapu
- Histology Laboratory, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Arthur Beyder
- Division of Gastroenterology and Hepatology, and Enteric Neurosciences Program, Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- Division of Gastroenterology and Hepatology, and Enteric Neurosciences Program, Mayo Clinic, Rochester, Minnesota
| | | | - Gregory B Sands
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Surgery, Vanderbilt University, Nashville, Tennessee
| | - Timothy R Angeli-Gordon
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
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21
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O'Grady G, Carbone F, Tack J. Gastric sensorimotor function and its clinical measurement. Neurogastroenterol Motil 2022; 34:e14489. [PMID: 36371709 PMCID: PMC10078602 DOI: 10.1111/nmo.14489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/24/2022] [Accepted: 10/24/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Gastroduodenal symptoms are highly prevalent, with underlying sensorimotor dysfunction contributing in many patients. Common symptoms include early satiation, postprandial fullness, epigastric bloating, pain or burning, nausea and vomiting, which collectively affect over 7% of adults. However, the clinical evaluation of these symptoms remains challenging, with current tests of gastric function remaining limited in their ability or availability to separate specific patient subgroups or guide-targeted care. PURPOSE In the current edition of Neurogastroenterology & Motility, Silver et al. present new data showing correlations between patterns of intragastric meal distribution and symptom profiles in a large series of patients undergoing gastric emptying scintigraphy. Studies of this type are important, as they motivate understanding beyond existing disease labels, and orient focus toward deeper mechanistic profiling. This brief review provides an overview of gastric sensorimotor function and profiles several current and emerging methods of clinical evaluation. Perspectives are provided on accommodation testing, gastric emptying, measuring gastric myoelectrical activity including new approaches, and antroduodenal manometry. Although gastric physiology is complex, recent progress has been encouraging, with the heterogenous pathophysiology of gastric symptoms continuing to be unraveled, and new techniques for evaluating gastric function and symptoms emerging. CONCLUSIONS AND INFERENCES Ongoing progress will now depend on continuing to accurately profile the underlying mechanisms of gastroduodenal disorders to identify specific disease phenotypes that inform care.
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Affiliation(s)
- Greg O'Grady
- Department of Surgery, The University of Auckland, Auckland, New Zealand.,Alimetry Ltd, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Florencia Carbone
- Department of Gastroenterology, University Hospital Leuven (UZ Leuven), Leuven, Belgium
| | - Jan Tack
- Department of Gastroenterology, University Hospital Leuven (UZ Leuven), Leuven, Belgium.,Translational Research Center for Gastrointestinal Diseases (TARGID), department of Chronic Diseases and Metabolism (ChroMeta), University of Leuven, Leuven, Belgium.,Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Rome Foundation, Raleigh, North Carolina, USA
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22
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Kuhar S, Lee JH, Seo JH, Pasricha PJ, Mittal R. Effect of stomach motility on food hydrolysis and gastric emptying: Insight from computational models. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2022; 34:111909. [PMID: 36407285 PMCID: PMC9667910 DOI: 10.1063/5.0120933] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
The peristaltic motion of stomach walls combines with the secretion of digestive enzymes to initiate the process that breaks down food. In this study, the mixing, breakdown, and emptying of a liquid meal containing protein is simulated in a model of a human stomach. In this model, pepsin, the gastric enzyme responsible for protein hydrolysis, is secreted from the proximal region of the stomach walls and allowed to react with the contents of the stomach. The velocities of the retropulsive jet induced by the peristaltic motion, the emptying rate, and the extent of hydrolysis are quantified for a control case as well as for three other cases with reduced motility of the stomach, which may result from conditions such as diabetes mellitus. This study quantifies the effect of stomach motility on the rate of food breakdown and its emptying into the duodenum and we correlate these observations with the mixing in the stomach induced by the wall motion.
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Affiliation(s)
- Sharun Kuhar
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | | | | | - Pankaj J Pasricha
- Division of Gastroenterology and Hepatology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, USA
| | - Rajat Mittal
- Author to whom correspondence should be addressed:
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23
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Calder S, Cheng LK, Andrews CN, Paskaranandavadivel N, Waite S, Alighaleh S, Erickson JC, Gharibans A, O'Grady G, Du P. Validation of noninvasive body-surface gastric mapping for detecting gastric slow-wave spatiotemporal features by simultaneous serosal mapping in porcine. Am J Physiol Gastrointest Liver Physiol 2022; 323:G295-G305. [PMID: 35916432 DOI: 10.1152/ajpgi.00049.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric disorders are increasingly prevalent, but reliable noninvasive tools to objectively assess gastric function are lacking. Body-surface gastric mapping (BSGM) is a noninvasive method for the detection of gastric electrophysiological features, which are correlated with symptoms in patients with gastroparesis and functional dyspepsia. Previous studies have validated the relationship between serosal and cutaneous recordings from limited number of channels. This study aimed to comprehensively evaluate the basis of BSGM from 64 cutaneous channels and reliably identify spatial biomarkers associated with slow-wave dysrhythmias. High-resolution electrode arrays were placed to simultaneously capture slow waves from the gastric serosa (32 × 6 electrodes at 4 mm spacing) and epigastrium (8 × 8 electrodes at 20 mm spacing) in 14 porcine subjects. BSGM signals were processed based on a combination of wavelet and phase information analyses. A total of 1,185 individual cycles of slow waves were assessed, out of which 897 (76%) were classified as normal antegrade waves, occurring in 10 (71%) subjects studied. BSGM accurately detected the underlying slow wave in terms of frequency (r = 0.99, P = 0.43) as well as the direction of propagation (P = 0.41, F-measure: 0.92). In addition, the cycle-by-cycle match between BSGM and transitions of gastric slow wave dysrhythmias was demonstrated. These results validate BSGM as a suitable method for noninvasively and accurately detecting gastric slow-wave spatiotemporal profiles from the body surface.NEW & NOTEWORTHY Gastric dysfunctions are associated with abnormalities in the gastric bioelectrical slow waves. Noninvasive detection of gastric slow waves from the body surface can be achieved through multichannel, high-resolution, body-surface gastric mapping (BSGM). BSGM matched the spatiotemporal characteristics of gastric slow waves recorded directly and simultaneously from the serosal surface of the stomach. Abnormal gastric slow waves, such as retrograde propagation, ectopic pacemaker, and colliding wavefronts can be detected by changes in the phase of BSGM.
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Affiliation(s)
- Stefan Calder
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Alimetry Ltd., Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Christopher N Andrews
- Alimetry Ltd., Auckland, New Zealand.,Division of Gastroenterology and Hepatology, University of Calgary, Calgary, Alberta, Canada
| | | | | | | | - Jonathan C Erickson
- Department of Physics-Engineering, Washington and Lee University, Lexington, Virginia
| | - Armen Gharibans
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Alimetry Ltd., Auckland, New Zealand
| | - Gregory O'Grady
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Alimetry Ltd., Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Alimetry Ltd., Auckland, New Zealand
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24
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Gharibans AA, Calder S, Varghese C, Waite S, Schamberg G, Daker C, Du P, Alighaleh S, Carson D, Woodhead J, Farrugia G, Windsor JA, Andrews CN, O'Grady G. Gastric dysfunction in patients with chronic nausea and vomiting syndromes defined by a noninvasive gastric mapping device. Sci Transl Med 2022; 14:eabq3544. [PMID: 36130019 PMCID: PMC10042458 DOI: 10.1126/scitranslmed.abq3544] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Chronic nausea and vomiting syndromes (NVSs) are prevalent and debilitating disorders. Putative mechanisms include gastric neuromuscular disease and dysregulation of brain-gut interaction, but clinical tests for objectively defining gastric motor function are lacking. A medical device enabling noninvasive body surface gastric mapping (BSGM) was developed and applied to evaluate NVS pathophysiology. BSGM was performed in 43 patients with NVS and 43 matched controls using Gastric Alimetry (Alimetry), a conformable high-resolution array (8 × 8 electrodes; 20-mm interelectrode spacing), wearable reader, and validated symptom-logging app. Continuous measurement encompassed a fasting baseline (30 minutes), 482-kilocalorie meal, and 4-hour postprandial recording, followed by spectral and spatial biomarker analyses. Meal responses were impaired in NVS, with reduced amplitudes compared to controls (median, 23.3 microvolts versus 38.0 microvolts, P < 0.001), impaired fed-fasting power ratios (1.1 versus 1.6, P = 0.02), and disorganized slow waves (spatial frequency stability, 13.6 versus 49.5; P < 0.001). Two distinct NVS subgroups were evident with indistinguishable symptoms (all P > 0.05). Most patients (62%) had normal BSGM studies with increased psychological comorbidities (43.5% versus 7.7%; P = 0.03) and anxiety scores (median, 16.5 versus 13.0; P = 0.035). A smaller subgroup (31%) had markedly abnormal BSGM, with biomarkers correlating with symptoms (nausea, pain, excessive fullness, early satiety, and bloating; all r > 0.35, P < 0.05). Patients with NVS share overlapping symptoms but comprise distinct underlying phenotypes as revealed by a BSGM device. These phenotypes correlate with symptoms, which should inform clinical management and therapeutic trial design.
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Affiliation(s)
- Armen A Gharibans
- Surgical and Translational Research Centre, University of Auckland, Auckland 1023, New Zealand.,Alimetry Ltd., Auckland 1010, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | - Stefan Calder
- Surgical and Translational Research Centre, University of Auckland, Auckland 1023, New Zealand.,Alimetry Ltd., Auckland 1010, New Zealand
| | - Chris Varghese
- Surgical and Translational Research Centre, University of Auckland, Auckland 1023, New Zealand
| | | | | | - Charlotte Daker
- Department of Gastroenterology, North Shore Hospital, Auckland 0620, New Zealand
| | - Peng Du
- Alimetry Ltd., Auckland 1010, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
| | | | - Daniel Carson
- Surgical and Translational Research Centre, University of Auckland, Auckland 1023, New Zealand
| | | | | | - John A Windsor
- Surgical and Translational Research Centre, University of Auckland, Auckland 1023, New Zealand
| | - Christopher N Andrews
- Division of Gastroenterology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Greg O'Grady
- Surgical and Translational Research Centre, University of Auckland, Auckland 1023, New Zealand.,Alimetry Ltd., Auckland 1010, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
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25
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Athavale ON, Cheng LK, Clark AR, Avci R, Du P. Mathematical Modeling of Gastric Slow Waves During Electrical Field Stimulation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:2266-2269. [PMID: 36086185 DOI: 10.1109/embc48229.2022.9871307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
While neural modulation has been trialed as a therapy for functional gastric motility disorders, a computational model that guides stimulation protocol does not exist. In this work, a mathematical model of gastric slow wave activity, which incorporates the effects of neurotransmitter release during electrical field stimulation (EFS), was developed. Slow wave frequency responses due to the release of acetylcholine and slow wave amplitude responses due to the release of nitric oxide were modeled. The model was calibrated using experimental data from literature. A sensitivity analysis was conducted, which showed that the model yielded stable, periodic solutions for EFS frequencies in the range 0-20 Hz. A 25% increase in the input parameter (EFS frequency) from 5 Hz to 6.25 Hz resulted in a 5.2% increase in slow wave frequency and a 3.2 % decrease in slow wave amplitude. Simulated EFS showed that, for stimulation at 15 Hz, with blocking of the nitrergic neurotransmitter pathway the slow wave increased from the no stimulation scenario in frequency by only 2.4x compared to 2.7x when the nitrergic pathway was not blocked. A 21 % reduction in slow wave amplitude occurred when the cholinergic pathway was blocked, compared to a 46% reduction when no neurotransmitter pathways were blocked. Clinical relevance - This mathematical model is a step towards successful computational modeling of the effects ther-apeutic neural stimulation on the stomach. The model is also a tool for understanding of the physiology of neural stimulation.
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26
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Ding F, Guo R, Cui ZY, Hu H, Zhao G. Clinical application and research progress of extracellular slow wave recording in the gastrointestinal tract. World J Gastrointest Surg 2022; 14:544-555. [PMID: 35979419 PMCID: PMC9258241 DOI: 10.4240/wjgs.v14.i6.544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/21/2022] [Accepted: 05/17/2022] [Indexed: 02/06/2023] Open
Abstract
The physiological function of the gastrointestinal (GI) tract is based on the slow wave generated and transmitted by the interstitial cells of Cajal. Extracellular myoelectric recording techniques are often used to record the characteristics and propagation of slow wave and analyze the models of slow wave transmission under physiological and pathological conditions to further explore the mechanism of GI dysfunction. This article reviews the application and research progress of electromyography, bioelectromagnetic technology, and high-resolution mapping in animal and clinical experiments, summarizes the clinical application of GI electrical stimulation therapy, and reviews the electrophysiological research in the biliary system.
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Affiliation(s)
- Fan Ding
- Center of Gallbladder Disease, East Hospital of Tongji University, Shanghai 200120, China
- Institute of Gallstone Disease, Tongji University School of Medicine, Shanghai 200331, China
| | - Run Guo
- Department of Ultrasonography, East Hospital of Tongji University, Shanghai 200120, China
| | - Zheng-Yu Cui
- Department of Internal Medicine of Traditional Chinese Medicine, East Hospital of Tongji University, Shanghai 200120, China
| | - Hai Hu
- Center of Gallbladder Disease, East Hospital of Tongji University, Shanghai 200120, China
- Institute of Gallstone Disease, Tongji University School of Medicine, Shanghai 200331, China
| | - Gang Zhao
- Center of Gallbladder Disease, East Hospital of Tongji University, Shanghai 200120, China
- Institute of Gallstone Disease, Tongji University School of Medicine, Shanghai 200331, China
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27
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Straface M, Koussai MA, Makwana R, Crawley E, Palmer A, Cai W, Gharibans A, Adebibe M, Loy J, O’Grady G, Andrews PLR, Sanger GJ. A multi-parameter approach to measurement of spontaneous myogenic contractions in human stomach: Utilization to assess potential modulators of myogenic contractions. Pharmacol Res 2022; 180:106247. [DOI: 10.1016/j.phrs.2022.106247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/22/2022] [Accepted: 05/03/2022] [Indexed: 10/18/2022]
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28
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Aghababaie Z, Cheng LK, Paskaranandavadivel N, Avci R, Chan CHA, Matthee A, Amirapu S, Asirvatham SJ, Farrugia G, Beyder A, O’Grady G, Angeli-Gordon TR. Targeted ablation of gastric pacemaker sites to modulate patterns of bioelectrical slow wave activation and propagation in an anesthetized pig model. Am J Physiol Gastrointest Liver Physiol 2022; 322:G431-G445. [PMID: 35137624 PMCID: PMC8917929 DOI: 10.1152/ajpgi.00332.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric motility is coordinated by underlying bioelectrical slow waves. Gastric dysrhythmias occur in gastrointestinal (GI) motility disorders, but there are no validated methods for eliminating dysrhythmias. We hypothesized that targeted ablation could eliminate pacemaker sites in the stomach, including dysrhythmic ectopic pacemaker sites. In vivo high-resolution serosal electrical mapping (16 × 16 electrodes; 6 × 6 cm) was applied to localize normal and ectopic gastric pacemaker sites in 13 anesthetized pigs. Radiofrequency ablation was performed in a square formation surrounding the pacemaker site. Postablation high-resolution mapping revealed that ablation successfully induced localized conduction blocks after 18 min (SD 5). Normal gastric pacemaker sites were eliminated by ablation (n = 6), resulting in the emergence of a new pacemaker site immediately distal to the original site in all cases. Ectopic pacemaker sites were similarly eliminated by ablation in all cases (n = 7), and the surrounding mapped area was then entrained by normal antegrade activity in five of those cases. Histological analysis showed that ablation lesions extended through the entire depth of the muscle layer. Immunohistochemical staining confirmed localized interruption of the interstitial cell of Cajal (ICC) network through the ablation lesions. This study demonstrates that targeted gastric ablation can effectively modulate gastric electrical activation, including eliminating ectopic sites of slow wave activation underlying gastric dysrhythmias, without disrupting surrounding conduction capability or tissue structure. Gastric ablation presents a powerful new research tool for modulating gastric electrical activation and may likely hold therapeutic potential for disorders of gastric function.NEW & NOTEWORTHY This study presents gastric ablation as a novel tool for modulating gastric bioelectrical activation, including eliminating the normal gastric pacemaker site as well as abnormal ectopic pacemaker sites underlying gastric dysrhythmias. Targeted application of radiofrequency ablation was able to eliminate these pacemaker sites without disrupting surrounding conduction capability or tissue structure. Gastric ablation presents a powerful new research tool for modulating gastric electrical activation and may likely hold therapeutic potential for disorders of gastric function.
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Affiliation(s)
- Zahra Aghababaie
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K. Cheng
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,2Department of Surgery, Vanderbilt University, Nashville, Tennessee
| | | | - Recep Avci
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Ashton Matthee
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Satya Amirapu
- 3Histology Laboratory, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | | | - Gianrico Farrugia
- 5Division of Gastroenterology and Hepatology and Enteric Neurosciences Program, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- 5Division of Gastroenterology and Hepatology and Enteric Neurosciences Program, Mayo Clinic, Rochester, Minnesota
| | - Gregory O’Grady
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,6Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Timothy R. Angeli-Gordon
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,6Department of Surgery, University of Auckland, Auckland, New Zealand
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