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Kuruppu S, Cheng LK, Angeli-Gordon TR, Avci R, Paskaranandavadivel N. Electromechanical Response of Mesenteric Ischemia Defined Through Simultaneous High-Resolution Bioelectrical and Video Mapping. Ann Biomed Eng 2024; 52:588-599. [PMID: 37962674 DOI: 10.1007/s10439-023-03404-w] [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: 05/30/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
Intestinal motility is governed in part by bioelectrical slow-waves and spike-bursts. Mesenteric ischemia is a substantial clinical challenge, but its electrophysiological and contractile mechanisms are not well understood. Simultaneous high-resolution bioelectrical and video mapping techniques were used to capture the changes in slow-waves, spike-bursts, and contractile activity during baseline, ischemia, and reperfusion periods. Experiments were performed on anesthetized pigs where intestinal contractions were quantified using surface strain and diameter measurements, while slow-wave and spike-bursts were quantified using frequency and amplitude. Slow-waves entrainment within the ischemic region diminished during ischemia, resulting in irregular slow-wave activity and a reduction in the frequency from 12.4 ± 3.0 cycles-per-minute (cpm) to 2.5 ± 2.7 cpm (p = 0.0006). At the end of the reperfusion period, normal slow-wave entrainment was observed at a frequency of 11.5 ± 2.9 cpm. There was an increase in spike-burst activity between the baseline and ischemia periods (1.1 ± 1.4 cpm to 8.7 ± 3.3 cpm, p = 0.0003) along with a spasm of circumferential contractions. At the end of the reperfusion period, the frequency of spike-bursts decreased to 2.7 ± 1.4 cpm, and contractions subsided. The intestine underwent tonal contraction during ischemia, with the diameter decreasing from 29.3 ± 2.6 mm to 21.2 ± 6.2 mm (p = 0.0020). At the end of the reperfusion period, the intestinal diameter increased to 27.3 ± 3.9 mm. The decrease in slow-wave activity, increase in spike-bursts, and tonal contractions can objectively identify ischemic segments in the intestine. It is anticipated that the use of electrophysiological slow-wave and spike-burst biomarkers, along with contractile measures, could identify mesenteric ischemia in surgical settings and allow an objective biomarker for successful revascularization.
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Affiliation(s)
- Sachira Kuruppu
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Riddet Institute, Centre of Research Excellence, Palmerston North, New Zealand
| | - Timothy R Angeli-Gordon
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
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2
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Doguet M, Oster J, Malka-Mahieu H, Doyen M, Odille F. Body Surface Gastrointestinal Potential Mapping: A Simulation Framework to Evaluate Source Separation Algorithms . ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083102 DOI: 10.1109/embc40787.2023.10340911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Gastrointestinal (GI) potential mapping could be useful for evaluating GI motility disorders. Such disorders are found in inflammatory bowel diseases, such as Crohn's disease, or GI functional disorders. GI potential mapping data originate from a mixture of several GI electrophysiological sources (termed ExG) and other noise sources, including the electrocardiogram (ECG) and respiration. Denoising and/or source separation techniques are required, however, with real measurements, no ground truth is available. In this paper we propose a framework for the simulation of body surface GI potential mapping data. The framework is an electrostatic model, based on fecgsyn toolbox, using dipoles as electrical sources for the heart, stomach, small bowel and colon, and an array of surface electrodes. It is shown to generate realistic ExG waveforms, which are then used to compare several ECG and respiration cancellation techniques, based on, fast independent component analysis (FastICA) and pseudo-periodic component analysis (PiCA). The best performance was obtained with PiCA with a median root mean squared error of 0.005.
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Nagahawatte ND, Cheng LK, Avci R, Angeli-Gordon TR, Paskaranandavadivel N. Systematic review of small intestine pacing parameters for modulation of gut function. Neurogastroenterol Motil 2023; 35:e14473. [PMID: 36194179 PMCID: PMC10078404 DOI: 10.1111/nmo.14473] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 08/22/2022] [Accepted: 09/12/2022] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND PURPOSE The efficacy of conventional treatments for severe and chronic functional motility disorders remains limited. High-energy pacing is a promising alternative therapy for patients that fail conventional treatment. Pacing primarily regulates gut motility by modulating rhythmic bio-electrical events called slow waves. While the efficacy of this technique has been widely investigated on the stomach, its application in the small intestine is less developed. This systematic review was undertaken to summarize the status of small intestinal pacing and evaluate its efficacy in modulating bowel function through preclinical research studies. METHODS The literature was searched using Scopus, PubMed, Ovid, Cochrane, CINAHL, and Google Scholar. Studies investigating electrophysiological, motility, and/or nutrient absorption responses to pacing were included. A critical review of all included studies was conducted comparing study outcomes against experimental protocols. RESULTS The inclusion criteria were met by 34 publications. A range of pacing parameters including amplitude, pulse width, pacing direction, and its application to broad regional small intestinal segments were identified and assessed. Out of the 34 studies surveyed, 20/23 studies successfully achieved slow-wave entrainment, 9/11 studies enhanced nutrient absorption and 21/27 studies modulated motility with pacing. CONCLUSION Small intestine pacing shows therapeutic potential in treating disorders such as short bowel syndrome and obesity. This systematic review proposes standardized protocols to maximize research outcomes and thereby translate to human studies for clinical validation. The use of novel techniques such as high-resolution electrical, manometric, and optical mapping in future studies will enable a mechanistic understanding of pacing.
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Affiliation(s)
- Nipuni D Nagahawatte
- 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, USA.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - 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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Miller KJW, Cheng LK, Angeli-Gordon TR, Avci R, Paskaranandavadivel N. The bioelectrical conduction system around the ileocecal junction defined through in vivo high-resolution mapping in rabbits. Am J Physiol Gastrointest Liver Physiol 2022; 323:G318-G330. [PMID: 35916409 DOI: 10.1152/ajpgi.00329.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Coordinated contractions across the small and large intestines via the ileocecal junction (ICJ) are critical to healthy gastrointestinal function and are in part governed by myoelectrical activity. In this study, the spatiotemporal characteristics of the bioelectrical conduction across the ICJ and its adjacent regions were quantified in anesthetized rabbits. High-resolution mapping was applied from the terminal ileum (TI) to the sacculus rotundus (SR), across the ICJ and into the beginning of the large intestine at the cecum ampulla coli (AC). Orally propagating slow wave patterns in the SR did not entrain the TI. However, aborally propagating patterns from the TI were able to entrain the SR. Bioelectrical activity was recorded within the ICJ and AC, revealing complex interactions of slow waves, spike bursts, and bioelectrical quiescence. This suggests the involvement of myogenic coordination when regulating motility between the small and large intestines. Mean slow wave frequency between regions did not vary significantly (13.74-17.16 cycles/min). Slow waves in the SR propagated with significantly faster speeds (18.51 ± 1.57 mm/s) compared with the TI (14.05 ± 2.53 mm/s, P = 0.0113) and AC (9.56 ± 1.56 mm/s, P = 0.0001). Significantly higher amplitudes were observed in both the TI (0.28 ± 0.13 mV, P = 0.0167) and SR (0.24 ± 0.08 mV, P = 0.0159) within the small intestine compared with the large intestine AC (0.03 ± 0.01 mV). We hypothesize that orally propagating slow waves facilitate a motor-brake pattern in the SR to limit outflow into the ICJ, similar to those previously observed in other gastrointestinal regions.NEW & NOTEWORTHY Competing slow wave pacemakers were observed in the terminal ileum and sacculus rotundus. Prevalent oral propagation in the sacculus rotundus toward the terminal ileum potentially acts as a brake mechanism limiting outflow. Slow waves and periods of quiescence at the ileocecal junction suggest that activation may depend on the coregulatory flow and distention pathways. Slow waves and spike bursts in the cecum impart a role in the coordination of motility.
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Affiliation(s)
- Kiara J W Miller
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute, Palmerston North, New Zealand
| | - Timothy R Angeli-Gordon
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute, Palmerston North, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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Nan K, Feig VR, Ying B, Howarth JG, Kang Z, Yang Y, Traverso G. Mucosa-interfacing electronics. NATURE REVIEWS. MATERIALS 2022; 7:908-925. [PMID: 36124042 PMCID: PMC9472746 DOI: 10.1038/s41578-022-00477-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
The surface mucosa that lines many of our organs houses myriad biometric signals and, therefore, has great potential as a sensor-tissue interface for high-fidelity and long-term biosensing. However, progress is still nascent for mucosa-interfacing electronics owing to challenges with establishing robust sensor-tissue interfaces; device localization, retention and removal; and power and data transfer. This is in sharp contrast to the rapidly advancing field of skin-interfacing electronics, which are replacing traditional hospital visits with minimally invasive, real-time, continuous and untethered biosensing. This Review aims to bridge the gap between skin-interfacing electronics and mucosa-interfacing electronics systems through a comparison of the properties and functions of the skin and internal mucosal surfaces. The major physiological signals accessible through mucosa-lined organs are surveyed and design considerations for the next generation of mucosa-interfacing electronics are outlined based on state-of-the-art developments in bio-integrated electronics. With this Review, we aim to inspire hardware solutions that can serve as a foundation for developing personalized biosensing from the mucosa, a relatively uncharted field with great scientific and clinical potential.
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Affiliation(s)
- Kewang Nan
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
- Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA
| | - Vivian R. Feig
- Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Binbin Ying
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
- Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA
| | - Julia G. Howarth
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Ziliang Kang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
- Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA
| | - Yiyuan Yang
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Giovanni Traverso
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA USA
- Division of Gastroenterology, Hepatology and Endoscopy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA USA
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6
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Nagahawatte ND, Zhang H, Paskaranandavadivel N, Patton HN, Garrett AS, Angeli-Gordon TR, Nisbet L, Rogers JM, Cheng LK. Gastric pacing response evaluated with simultaneous electrical and optical mapping. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:2224-2227. [PMID: 36086523 DOI: 10.1109/embc48229.2022.9871138] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Gastric pacing is an attractive therapeutic approach for correcting abnormal bioelectrical activity. While high-resolution (HR) electrical mapping techniques have largely contributed to the current understanding of the effect of pacing on the electrophysiological function, these mapping techniques are restricted to surface contact electrodes and the signal quality can be corrupted by pacing artifacts. Optical mapping of voltage sensitive dyes is an alternative approach used in cardiac research, and the signal quality is not affected by pacing artifacts. In this study, we simultaneously applied HR optical and electrical mapping techniques to evaluate the bioelectrical slow wave response to gastric pacing. The studies were conducted in vivo on porcine stomachs ( n=3) where the gastric electrical activity was entrained using high-energy pacing. The pacing response was optically tracked using voltage-sensitive fluorescent dyes and electrically tracked using surface contact electrodes positioned on adjacent regions. Slow waves were captured optically and electrically and were concordant in time and direction of propagation with comparable mean velocities ([Formula: see text]) and periods ([Formula: see text]). Importantly, the optical signals were free from pacing artifacts otherwise induced in electrical recordings highlighting an advantage of optical mapping. Clinical Relevance- Entrainment mapping of gastric pacing using optical techniques is a major advance for improving the preclinical understanding of the therapy. The findings can thereby inform the efficacy of gastric pacing in treating functional motility disorders.
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7
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Willis D, Cameron D, Kasmai B, Vassiliou VS, Malcolm PN, Baio G. A novel method for measuring bowel motility and velocity with dynamic magnetic resonance imaging in two and three dimensions. NMR IN BIOMEDICINE 2022; 35:e4663. [PMID: 34913200 DOI: 10.1002/nbm.4663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 11/02/2021] [Accepted: 11/19/2021] [Indexed: 06/14/2023]
Abstract
Increasingly, dynamic magnetic resonance imaging (MRI) has potential as a noninvasive and accessible tool for diagnosing and monitoring gastrointestinal motility in healthy and diseased bowel. However, current MRI methods of measuring bowel motility have limitations: requiring bowel preparation or long acquisition times; providing mainly surrogate measures of motion; and estimating bowel-wall movement in just two dimensions. In this proof-of-concept study we apply a method that provides a quantitative measure of motion within the bowel, in both two and three dimensions, using existing, vendor-implemented MRI pulse sequences with minimal bowel preparation. This method uses a minimised cost function to fit linear vectors in the spatial and temporal domains. It is sensitised to the spatial scale of the bowel and aims to address issues relating to the low signal-to-noise in high-temporal resolution dynamic MRI scans, previously compensated for by performing thick-slice (10-mm) two-dimensional (2D) coronal scans. We applied both 2D and three-dimensional (3D) scanning protocols in two healthy volunteers. For 2D scanning, analysis yielded bi-modal velocity peaks, with a mean antegrade motion of 5.5 mm/s and an additional peak at ~9 mm/s corresponding to longitudinal peristalsis, as supported by intraoperative data from the literature. Furthermore, 3D scans indicated a mean forward motion of 4.7 mm/s, and degrees of antegrade and retrograde motion were also established. These measures show promise for the noninvasive assessment of bowel motility, and have the potential to be tuned to particular regions of interest and behaviours within the bowel.
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Affiliation(s)
- David Willis
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Donnie Cameron
- Norwich Medical School, University of East Anglia, Norwich, UK
- C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bahman Kasmai
- Department of Radiology, Norfolk & Norwich University Hospital NHS Trust, Norwich, UK
| | | | - Paul N Malcolm
- Department of Radiology, Norfolk & Norwich University Hospital NHS Trust, Norwich, UK
| | - Gabriella Baio
- Norwich Medical School, University of East Anglia, Norwich, UK
- Department of Radiology, Norfolk & Norwich University Hospital NHS Trust, Norwich, UK
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8
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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: 9] [Impact Index Per Article: 4.5] [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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9
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Savage M, Avci R, Aghababaie Z, Matthee A, Chamani F, Prakash P, Cheng LK, Angeli-Gordon TR. A computational model of radiofrequency ablation in the stomach, an emerging therapy for gastric dysrhythmias. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:1495-1498. [PMID: 34891568 DOI: 10.1109/embc46164.2021.9630633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gastric ablation has recently emerged as a promising potential therapy for bioelectrical dysrhythmias that underpin many gastrointestinal disorders. Despite similarities to well-developed cardiac ablation, gastric ablation is in early development and has thus far been limited to temperature-controlled, non-irrigated settings. A computational model of gastric ablation is needed to enable in silico testing and optimization of ablation parameters and techniques. In this study, we developed a computational model of radio-frequency (RF) gastric ablation. Model parameters and boundary conditions were established based on the current in vivo experimental application of serosal gastric ablation with a non-irrigated RF catheter. The Pennes bioheat transfer equation was used to model the thermal component of RF ablation, and Laplace's equation was used to model the Joule heating component. Tissue, blood, and catheter parameters were obtained from literature. The performance of the model was compared to previously established experimental values of temperature measured from various distances from the catheter tip. The model produced temperature estimations that were within 6% of the maximum experimental temperature at 2.5 mm from the catheter, and within 13% of the maximum temperature change at 4.7 mm. This model now provides a computational basis through which to conduct in silico testing of gastric ablation, and can be usefully applied to optimize gastric ablation parameters. In future, the model can be expanded to include irrigation of the catheter tip and power-controlled RF settings.Clinical Relevance- This work presents a computational model of gastric ablation that can now guide the in silico development of effective ablation parameters and therapeutic strategies, expanding the breadth of this promising therapy.
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10
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Lin AY, Varghese C, Du P, Wells CI, Paskaranandavadivel N, Gharibans AA, Erickson JC, Bissett IP, O'Grady G. Intraoperative serosal extracellular mapping of the human distal colon: a feasibility study. Biomed Eng Online 2021; 20:105. [PMID: 34656127 PMCID: PMC8520224 DOI: 10.1186/s12938-021-00944-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/05/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Cyclic motor patterns (CMP) are the predominant motor pattern in the distal colon, and are important in both health and disease. Their origin, mechanism and relation to bioelectrical slow-waves remain incompletely understood. During abdominal surgery, an increase in the CMP occurs in the distal colon. This study aimed to evaluate the feasibility of detecting propagating slow waves and spike waves in the distal human colon through intraoperative, high-resolution (HR), serosal electrical mapping. METHODS HR electrical recordings were obtained from the distal colon using validated flexible PCB arrays (6 × 16 electrodes; 4 mm inter-electrode spacing; 2.4 cm2, 0.3 mm diameter) for up to 15 min. Passive unipolar signals were obtained and analysed. RESULTS Eleven patients (33-71 years; 6 females) undergoing colorectal surgery under general anaesthesia (4 with epidurals) were recruited. After artefact removal and comprehensive manual and automated analytics, events consistent with regular propagating activity between 2 and 6 cpm were not identified in any patient. Intermittent clusters of spike-like activities lasting 10-180 s with frequencies of each cluster ranging between 24 and 42 cpm, and an average amplitude of 0.54 ± 0.37 mV were recorded. CONCLUSIONS Intraoperative colonic serosal mapping in humans is feasible, but unlike in the stomach and small bowel, revealed no regular propagating electrical activity. Although sporadic, synchronous spike-wave events were identifiable. Alternative techniques are required to characterise the mechanisms underlying the hyperactive CMP observed in the intra- and post-operative period. NEW FINDINGS The aim of this study was to assess the feasibility of detecting propagating electrical activity that may correlate to the cyclic motor pattern in the distal human colon through intraoperative, high-resolution, serosal electrical mapping. High-resolution electrical mapping of the human colon revealed no regular propagating activity, but does reveal sporadic spike-wave events. These findings indicate that further research into appropriate techniques is required to identify the mechanism of hyperactive cyclic motor pattern observed in the intra- and post-operative period in humans.
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Affiliation(s)
- Anthony Y Lin
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Cameron I Wells
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
| | | | - Armen A Gharibans
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Jonathan C Erickson
- Department of Physics-Engineering, Washington & Lee University, Lexington, VA, USA
| | - Ian P Bissett
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand.,Department of Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Greg O'Grady
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand. .,Department of Surgery, Auckland City Hospital, Auckland, New Zealand.
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11
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Nagahawatte ND, Paskaranandavadivel N, Angeli-Gordon TR, Cheng LK, Avci R. Transmural recordings of gastrointestinal electrical activity using a spatially-dense microelectrode array. Physiol Meas 2021; 42. [PMID: 33607644 DOI: 10.1088/1361-6579/abe80f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/19/2021] [Indexed: 11/11/2022]
Abstract
Objective. High-resolution serosal recordings provide detailed information about the bioelectrical conduction patterns in the gastrointestinal (GI) tract. However, equivalent knowledge about the electrical activity through the GI tract wall remains largely unknown. This study aims to capture and quantify the bioelectrical activity across the wall of the GI tract.Approach. A needle-based microelectrode array was used to measure the bioelectrical activity across the GI wallin vivo. Quantitative and qualitative evaluations of transmural slow wave characteristics were carried out in comparison to the serosal slow wave features, through which the period, amplitude, and SNR metrics were quantified and statistically compared.Main results. Identical periods of 4.7 ± 0.3 s with amplitudes of 0.17 ± 0.04 mV versus 0.31 ± 0.1 mV and signal to noise ratios of 5.5 ± 1.3 dB versus 14.4 ± 1.1 dB were observed for transmural and serosal layers, respectively. Four different slow wave morphologies were observed across the transmural layers of the GI wall. Similar amplitudes were observed for all morphology types, and Type 1 and Type 2 were of the highest prevalence, dominating the outer and inner layers. Type 2 was exclusive to the middle layer while Type 4 was primarily observed in the middle layer as well.Significance. This study demonstrates the validity of new methodologies for measuring transmural slow wave activation in the GI wall and can now be applied to investigate the source and origin of GI dysrhythmias leading to dysmotility, and to validate novel therapeutics for GI health and disease.
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Affiliation(s)
- Nipuni D Nagahawatte
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Timothy R Angeli-Gordon
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand.,Department of Surgery, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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12
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Aghababaie Z, Paskaranandavadivel N, Amirapu S, Chan CHA, Du P, Asirvatham SJ, Farrugia G, Beyder A, O’Grady G, Cheng LK, Angeli-Gordon TR. Gastric ablation as a novel technique for modulating electrical conduction in the in vivo stomach. Am J Physiol Gastrointest Liver Physiol 2021; 320:G573-G585. [PMID: 33470186 PMCID: PMC8238161 DOI: 10.1152/ajpgi.00448.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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 wave" activity. Slow wave dysrhythmias are associated with motility disorders, including gastroparesis, offering an underexplored potential therapeutic target. Although ablation is widely used to treat cardiac arrhythmias, this approach has not yet been trialed for gastric electrical abnormalities. We hypothesized that ablation can create localized conduction blocks and modulate slow wave activation. Radiofrequency ablation was performed on the porcine serosa in vivo, encompassing a range of parameters (55-85°C, adjacent points forming a line, 5-10 s/point). High-resolution electrical mapping (16 × 16 electrodes; 6 × 6 cm) was applied to define baseline and acute postablation activation patterns. Tissue damage was evaluated by hematoxylin and eosin and c-Kit stains. Results demonstrated that RF ablation successfully induced complete conduction block and a full thickness lesion in the muscle layer at energy doses of 65-75°C for 5-10 s/point. Gastric ablation may hold therapeutic potential for gastric electrical abnormalities in the future.NEW & NOTEWORTHY This study presents gastric ablation as a new method for modulating slow wave activation and propagation in vivo, by creating localized electrical conduction blocks in the stomach, validated by high-resolution electrical mapping and histological tissue analysis. The results define the effective energy dose range for creating conduction blocks, while maintaining the mucosal and submucosal integrity, and demonstrate the electrophysiological effects of ablation. In future, gastric ablation can now be translated toward disrupting dysrhythmic slow wave activation.
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Affiliation(s)
- Zahra Aghababaie
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Niranchan Paskaranandavadivel
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,2Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Satya Amirapu
- 3Histology Laboratory, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | | | - Peng Du
- 1Auckland Bioengineering Institute, 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,2Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Leo K. Cheng
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,6Department of Surgery, Vanderbilt University, Nashville, Tennessee
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13
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Carson DA, O'Grady G, Du P, Gharibans AA, Andrews CN. Body surface mapping of the stomach: New directions for clinically evaluating gastric electrical activity. Neurogastroenterol Motil 2021; 33:e14048. [PMID: 33274564 DOI: 10.1111/nmo.14048] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/11/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Gastric motility disorders, which include both functional and organic etiologies, are highly prevalent. However, there remains a critical lack of objective biomarkers to guide efficient diagnostics and personalized therapies. Bioelectrical activity plays a fundamental role in coordinating gastric function and has been investigated as a contributing mechanism to gastric dysmotility and sensory dysfunction for a century. However, conventional electrogastrography (EGG) has not achieved common clinical adoption due to its perceived limited diagnostic capability and inability to impact clinical care. The last decade has seen the emergence of novel high-resolution methods for invasively mapping human gastric electrical activity in health and disease, providing important new insights into gastric physiology. The limitations of EGG have also now become clearer, including the finding that slow-wave frequency alone is not a reliable discriminator of gastric dysrhythmia, shifting focus instead toward altered spatial patterns. Recently, advances in bioinstrumentation, signal processing, and computational modeling have aligned to allow non-invasive body surface mapping of the stomach to detect spatiotemporal gastric dysrhythmias. The clinical relevance of this emerging strategy to improve diagnostics now awaits determination. PURPOSE This review evaluates these recent advances in clinical gastric electrophysiology, together with promising emerging data suggesting that novel gastric electrical signatures recorded at the body surface (termed "body surface mapping") may correlate with symptoms. Further technological progress and validation data are now awaited to determine whether these advances will deliver on the promise of clinical gastric electrophysiology diagnostics.
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Affiliation(s)
- Daniel A Carson
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Greg O'Grady
- Department of Surgery, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - Armen A Gharibans
- Department of Surgery, University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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14
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Penfold JA, Wells CI, Du P, Qian A, Vather R, Bissett IP, O'Grady G. Relationships between serum electrolyte concentrations and ileus: A joint clinical and mathematical modeling study. Physiol Rep 2021; 9:e14735. [PMID: 33527737 PMCID: PMC7851429 DOI: 10.14814/phy2.14735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/30/2020] [Accepted: 01/03/2021] [Indexed: 12/15/2022] Open
Abstract
Aim Prolonged postoperative ileus (PPOI) occurs in around 15% of patients after major abdominal surgery, posing a significant clinical and economic burden. Significant fluid and electrolyte changes may occur peri‐operatively, potentially contributing to PPOI; however, this association has not been clearly elucidated. A joint clinical‐theoretical study was undertaken to evaluate peri‐operative electrolyte concentration trends, their association with ileus, and predicted impact on bioelectrical slow waves in interstitial cells of Cajal (ICC) and smooth muscle cells (SMC). Methods Data were prospectively collected from 327 patients undergoing elective colorectal surgery. Analyses were performed to determine associations between peri‐operative electrolyte concentrations and prolonged ileus. Biophysically based ICC and SMC mathematical models were adapted to evaluate the theoretical impacts of extracellular electrolyte concentrations on cellular function. Results Postoperative day (POD) 1 calcium and POD 3 chloride, sodium were lower in the PPOI group (p < 0.05), and POD3 potassium was higher in the PPOI group (p < 0.05). Deficits beyond the reference range in PPOI patients were most notable for sodium (Day 3: 29.5% ileus vs. 18.5% no ileus, p = 0.04). Models demonstrated an 8.6% reduction in slow‐wave frequency following the measured reduction in extracellular NaCl on POD5, with associated changes in cellular slow‐wave morphology and amplitude. Conclusion Low serum sodium and chloride concentrations are associated with PPOI. Electrolyte abnormalities are unlikely to be a primary mechanism of ileus, but their pronounced effects on cellular electrophysiology predicted by modeling suggest these abnormalities may adversely impact motility recovery. Resolution and correction of electrolyte abnormalities in ileus may be clinically relevant.
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Affiliation(s)
- James A Penfold
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Cameron I Wells
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Anna Qian
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Ryash Vather
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Ian P Bissett
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand
| | - Gregory O'Grady
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
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15
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Johnson AC, Louwies T, Ligon CO, Greenwood-Van Meerveld B. Enlightening the frontiers of neurogastroenterology through optogenetics. Am J Physiol Gastrointest Liver Physiol 2020; 319:G391-G399. [PMID: 32755304 PMCID: PMC7717115 DOI: 10.1152/ajpgi.00384.2019] [Citation(s) in RCA: 2] [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
Neurogastroenterology refers to the study of the extrinsic and intrinsic nervous system circuits controlling the gastrointestinal (GI) tract. Over the past 5-10 yr there has been an explosion in novel methodologies, technologies and approaches that offer great promise to advance our understanding of the basic mechanisms underlying GI function in health and disease. This review focuses on the use of optogenetics combined with electrophysiology in the field of neurogastroenterology. We discuss how these technologies and tools are currently being used to explore the brain-gut axis and debate the future research potential and limitations of these techniques. Taken together, we consider that the use of these technologies will enable researchers to answer important questions in neurogastroenterology through fundamental research. The answers to those questions will shorten the path from basic discovery to new treatments for patient populations with disorders of the brain-gut axis affecting the GI tract such as irritable bowel syndrome (IBS), functional dyspepsia, achalasia, and delayed gastric emptying.
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Affiliation(s)
- Anthony C. Johnson
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma,3Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tijs Louwies
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Casey O. Ligon
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Beverley Greenwood-Van Meerveld
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma,4Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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16
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Miller KJW, Cheng LK, Angeli TR, Avci R, Paskaranandavadivel N. Design and Application of an Inflatable Cuff to Aid High-Resolution Intestinal Slow Wave Recordings . ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:3953-3956. [PMID: 33018865 DOI: 10.1109/embc44109.2020.9175219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Intestinal motility is coordinated by myogenic, neuronal and hormonal factors. Myogenic control of motility via bioelectric slow waves (SW) has been investigated using low-resolution and high-resolution (HR) electrical mapping techniques. Due to the highly conformable and irregular surface of the gut, suboptimal coverage of HR recordings may occur. In this study we designed and developed an inflatable cuff as a platform to apply even pressure across the intestinal surface to achieve consistent and reliable recordings. The inflatable cuff and a HR electrode array were applied in vivo to demonstrate the reliability of SW signal acquisition over a range of inflatable pressures (0 - 5 mm Hg). The frequency, amplitude, percentage of viable signals and signal to noise ratio metrics of the SW signals were computed and compared. Overall, with an increase in inflatable pressure from 0 to 5 mm Hg, the frequency did not change, but the amplitude of the SWs decreased from 0.10 to 0.07 mV. The noise levels were consistent across the range of inflatable pressure levels and the percentage of viable SW recordings improved significantly from 57% to 74% after application of 1 mm Hg of pressure. The inflatable and conformable cuff presented in this study provides a reliable platform for HR mapping of bioelectrical events in the intestines and other conformable organs.Clinical Relevance- This framework improves the quality and reliability of bioelectrical high-resolution recordings obtained from the small intestine. In the future, these recordings will improve our understanding of the pathophysiological mechanisms governing intestinal motility disorders and may provide clinicians with new strategies for diagnosis and treatment.
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17
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Liu Y, Ye F, Zhang S, Li S, Chen J. Characteristics of myoelectrical activities along the small intestine and their responses to test meals of different glycemic index in rats. Am J Physiol Regul Integr Comp Physiol 2020; 318:R997-R1003. [PMID: 32320266 DOI: 10.1152/ajpregu.00282.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The purpose of this study was to characterize intestinal myoelectrical activity along the small intestine and investigate its responses to test meals with different glycemic index at different locations. Sixteen rats were implanted with electrodes in the serosal surface of the duodenum, jejunum, and ileum. Intestinal myoelectrical activities were recorded from these electrodes for 30 min in the fasting state and 3 h after four kinds of meals with different glycemic index, together with the assessment of blood glucose. The results were as follows: 1) in the fasting state, the percentage of normal intestinal slow waves (%NISW) showed no difference; however, the dominant frequency (DF), power (DP), and percentage of spike activity superimposed on the intestinal slow wave (NS/M) were progressively decreased along the entire small intestine; 2) regular solid meal and Ensure solicited no changes in any parameters of intestinal myoelectrical activity; whereas glucose and glucose + glucagon significantly altered the %NISW, DF, DP, and NS/M, and the effects on the proximal intestine were opposite to those in the distal intestine; and 3) postprandial blood glucose level was significantly correlated with %NISW along the entire small intestine. We found that that, in addition to the well-known frequency gradient, there is also a gradual decrease in the DP and spikes along the small intestine in the fasting state. Glucose and hyperglycemic meals inhibit myoelectrical activities in the proximal small intestine but result in enhanced but more dysrhythmic intestinal myoelectrical activities. There is a significant negative correlation between the normality of intestinal slow waves and blood glucose.
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Affiliation(s)
- Yi Liu
- Veterans Research and Education Foundation, Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma.,The 1st Affiliated Hospital of Xi'an Jiaotong University, Shannxi, China.,Department of Physiology, University of Oklahoma, Oklahoma City, Oklahoma.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland
| | - Feng Ye
- Veterans Research and Education Foundation, Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma.,The 1st Affiliated Hospital of Xi'an Jiaotong University, Shannxi, China.,Department of Physiology, University of Oklahoma, Oklahoma City, Oklahoma.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland
| | - Sujuan Zhang
- Veterans Research and Education Foundation, Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma.,Department of Physiology, University of Oklahoma, Oklahoma City, Oklahoma.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland.,Department of Gastroenterology, Tianjin No. 254 Hospital, Tianjin, China
| | - Shiying Li
- Veterans Research and Education Foundation, Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland
| | - Jiande Chen
- Veterans Research and Education Foundation, Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma.,Division of Gastroenterology and Hepatology, Johns Hopkins Center for Neurogastroenterology, Baltimore, Maryland
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18
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Du P, Liu JYH, Sukasem A, Qian A, Calder S, Rudd JA. Recent progress in electrophysiology and motility mapping of the gastrointestinal tract using multi-channel devices. J R Soc N Z 2020. [DOI: 10.1080/03036758.2020.1735455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
- Department of Engineering Science, The University of Auckland, Auckland, New Zealand
| | - Julia Y. H. Liu
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
| | - Atchariya Sukasem
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Anna Qian
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Stefan Calder
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - John A. Rudd
- Faculty of Medicine, School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, People’s Republic of China
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19
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Kamat AA, Paskaranandavadivel N, Alighaleh S, Cheng LK, Angeli TR. Effects of Electrode Diameter and Contact Material on Signal Morphology of Gastric Bioelectrical Slow Wave Recordings. Ann Biomed Eng 2020; 48:1407-1418. [DOI: 10.1007/s10439-020-02457-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 01/11/2020] [Indexed: 12/14/2022]
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20
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Cherian Abraham A, Cheng LK, Angeli TR, Alighaleh S, Paskaranandavadivel N. Dynamic slow-wave interactions in the rabbit small intestine defined using high-resolution mapping. Neurogastroenterol Motil 2019; 31:e13670. [PMID: 31250520 DOI: 10.1111/nmo.13670] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 06/09/2019] [Accepted: 06/18/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND The motility in the small intestine is governed in part by myogenic bio-electrical events, known as slow waves. High-resolution multi-electrode mapping has improved our understanding of slow-wave propagation in the small intestine but has been applied in a limited number of in vivo animal studies. This study applied high-resolution mapping to investigate slow waves in the rabbit small intestine. METHODS A high-resolution flexible printed circuit board array (256 electrodes; 4 mm spacing) was applied in vivo to the rabbit intestine. Extracellular slow-wave activity was acquired sequentially along the length of the intestine. KEY RESULTS AND CONCLUSIONS The majority of the slow waves propagated in the antegrade direction (56%) while retrograde patterns were primarily observed in the distal intestine (29%). Colliding slow-wave events were observed across the length of the small intestine (15%). The interaction of competing pacemakers was mapped in spatiotemporal detail. The frequency and velocity of the slow waves were highest in the duodenum compared to ileum (20.0 ± 1.2 cpm vs 10.5 ± 0.9 cpm, P < 0.001; 14.4 ± 3.4 mm/s vs 12.3 ± 3.4 mm/s; P < 0.05). INFERENCES In summary, extracellular serosal slow-wave activity was quantified spatiotemporally along the length of the rabbit intestine. In particular, the study provides evidence toward the presence and interaction of slow-wave pacemakers acting along the small intestine and how they may contribute to the slow-wave frequency gradient along the length of the intestine.
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Affiliation(s)
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Surgery, Vanderbilt University, Nashville, Tennessee, USA.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Timothy R Angeli
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Saeed Alighaleh
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Niranchan Paskaranandavadivel
- 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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Wang THH, Angeli TR, Beban G, Du P, Bianco F, Gibbons SJ, Windsor JA, Cheng LK, O’Grady G. Slow-wave coupling across a gastroduodenal anastomosis as a mechanism for postsurgical gastric dysfunction: evidence for a "gastrointestinal aberrant pathway". Am J Physiol Gastrointest Liver Physiol 2019; 317:G141-G146. [PMID: 31169993 PMCID: PMC6734376 DOI: 10.1152/ajpgi.00002.2019] [Citation(s) in RCA: 20] [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
Postsurgical gastric dysfunction is common, but the mechanisms are varied and poorly understood. The pylorus normally acts as an electrical barrier isolating gastric and intestinal slow waves. In this report, we present an aberrant electrical conduction pathway arising between the stomach and small intestine, following pyloric excision and surgical anastomosis, as a novel disease mechanism. A patient was referred with postsurgical gastroparesis following antrectomy, gastroduodenostomy, and vagotomy for peptic ulceration. Scintigraphy confirmed markedly abnormal 4-h gastric retention. Symptoms included nausea, vomiting, postprandial distress, and reflux. Intraoperative, high-resolution electrical mapping was performed across the anastomosis immediately before revision gastrectomy, and the resected anastomosis underwent immunohistochemistry for interstitial cells of Cajal. Mapping revealed continuous, stable abnormal retrograde slow-wave propagation through the anastomosis, with slow conduction occurring at the scar (4.0 ± 0.1 cycles/min; 2.5 ± 0.6 mm/s; 0.26 ± 0.15 mV). Stable abnormal retrograde propagation continued into the gastric corpus with tachygastria (3.9 ± 0.2 cycles/min; 1.6 ± 0.5 mm/s; 0.19 ± 0.12 mV). Histology confirmed ingrowth of atypical ICC through the scar, defining an aberrant pathway enabling transanastomotic electrical conduction. In conclusion, a "gastrointestinal aberrant pathway" is presented as a novel proposed cause of postsurgical gastric dysfunction. The importance of aberrant anastomotic conduction in acute and long-term surgical recovery warrants further investigation.NEW & NOTEWORTHY High-resolution gastric electrical mapping was performed during revisional surgery in a patient with severe gastric dysfunction following antrectomy and gastroduodenostomy. The results revealed continuous propagation of slow waves from the duodenum to the stomach, through the old anastomotic scar, and resulting in retrograde-propagating tachygastria. Histology showed atypical interstitial cells of Cajal growth through the anastomotic scar. Based on these results, we propose a "gastrointestinal aberrant pathway" as a mechanism for postsurgical gastric dysfunction.
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Affiliation(s)
- Tim H.-H. Wang
- 1Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Timothy R. Angeli
- 2Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Grant Beban
- 3Department of General Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Peng Du
- 2Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Francesca Bianco
- 4Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota,5Departments of Medical and Surgical Sciences (DIMEC) and Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Simon J. Gibbons
- 4Enteric Neuroscience Program, Mayo Clinic, Rochester, Minnesota
| | - John A. Windsor
- 1Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Leo K. Cheng
- 2Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,6Department of Surgery, Vanderbilt University, Nashville, Tennessee
| | - Gregory O’Grady
- 1Department of Surgery, University of Auckland, Auckland, New Zealand,2Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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22
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Huizinga JD, Parsons SP. Pacemaker network properties determine intestinal motor pattern behaviour. Exp Physiol 2019; 104:623-624. [PMID: 30834572 DOI: 10.1113/ep087465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 02/11/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Jan D Huizinga
- McMaster University, Farncombe Family Digestive Health Research Institute, Department of Medicine, Hamilton, Ontario, Canada
| | - Sean P Parsons
- McMaster University, Farncombe Family Digestive Health Research Institute, Department of Medicine, Hamilton, Ontario, Canada
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23
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Wells CI, O'Grady G, Bissett IP. Colonic Electromechanical Abnormalities Underlying Post-operative Ileus: A Systematic and Critical Review. J Neurogastroenterol Motil 2019; 25:36-47. [PMID: 30504526 PMCID: PMC6326204 DOI: 10.5056/jnm18030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/20/2018] [Accepted: 07/21/2018] [Indexed: 12/25/2022] Open
Abstract
Post-operative ileus (POI) is an inevitable consequence of major abdominal surgery, and may be prolonged in up to 30% of patients. Ileus is commonly presumed to result from paralysis of the GI tract, though there is little direct evidence to support this view. The aim of this review is to systematically search and critically review the literature investigating post-operative colonic electrical and mechanical activity. MEDLINE and Embase databases were systematically searched for articles investigating post-operative colonic motor or electrical activity in human patients. Nineteen original articles investigating post-operative colonic motor or electrical activity were identified. Most studies have used low-resolution techniques, with intermittent recordings of colonic motility. Numerous studies have shown that colonic electrical and motor activity does not cease routinely following surgery, but is of abnormal character for 3–6 days following laparotomy. One recent high-resolution manometry study identified hyperactive cyclic motor patterns occurring in the distal colon on the first post-operative day. Low-resolution studies have shown colonic slow waves are not inhibited by surgery, and are present even in the immediate post-operative period. Recovery of normal motility appears to occur in a proximal to distal direction and is temporally correlated with the clinical return of bowel function. No studies have investigated motility specifically in prolonged POI. Future studies should use high-resolution techniques to accurately characterise abnormalities in electrical and mechanical function underlying POI, and correlate these changes with clinical recovery of bowel function.
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Affiliation(s)
- Cameron I Wells
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand
| | - Gregory O'Grady
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, New Zealand
| | - Ian P Bissett
- Department of Surgery, Faculty of Medical and Health Sciences, The University of Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand
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24
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Huizinga JD. Recent advances in intestinal smooth muscle research: from muscle strips and single cells, via ICC networks to whole organ physiology and assessment of human gut motor dysfunction. J Smooth Muscle Res 2019; 55:68-80. [PMID: 31956167 PMCID: PMC6962316 DOI: 10.1540/jsmr.55.68] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 11/01/2019] [Indexed: 12/12/2022] Open
Abstract
Gastrointestinal smooth muscle research has evolved from studies on muscle strips to spatiotemporal mapping of whole organ motor and electrical activities. Decades of research on single muscle cells and small sections of isolated musculature from animal models has given us the groundwork for interpretation of human in vivo studies. Human gut motility studies have dramatically improved by high-resolution manometry and high-resolution electrophysiology. The details that emerge from spatiotemporal mapping of high-resolution data are now of such quality that hypotheses can be generated as to the physiology (in healthy subjects) and pathophysiology (in patients) of gastrointestinal (dys) motility. Such interpretation demands understanding of the musculature as a super-network of excitable cells (neurons, smooth muscle cells, other accessory cells) and oscillatory cells (the pacemaker interstitial cells of Cajal), for which mathematical modeling becomes essential. The developing deeper understanding of gastrointestinal motility will bring us soon to a level of precision in diagnosis of dysfunction that is far beyond what is currently available.
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Affiliation(s)
- Jan D. Huizinga
- Department of Medicine-Gastroenterology, McMaster University,
Hamilton, Ontario, Canada
- Farncombe Family Digestive Health Research Institute,
Hamilton, Ontario, Canada
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25
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Penfold JA, Wells CI, Du P, Bissett IP, O'Grady G. Electrical Stimulation and Recovery of Gastrointestinal Function Following Surgery: A Systematic Review. Neuromodulation 2018; 22:669-679. [PMID: 30451336 DOI: 10.1111/ner.12878] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 08/27/2018] [Accepted: 09/16/2018] [Indexed: 12/29/2022]
Abstract
OBJECTIVES Postoperative ileus occurs in approximately 5-15% of patients following major abdominal surgery, and poses a substantial clinical and economic burden. Electrical stimulation has been proposed as a means to aid postoperative gastrointestinal (GI) recovery, but no methods have entered routine clinical practice. A systematic review was undertaken to assess electrical stimulation techniques and to evaluate their clinical efficacy in order to identify promising areas for future research. MATERIALS AND METHODS Literature was searched using MEDLINE, EMBASE, Google Scholar and by assessing relevant clinical trial databases. Studies investigating the use of electrical stimulation for postoperative GI recovery were included, regardless of methods used or outcomes measured. A critical review was constructed encompassing all included studies and evaluating and synthesizing stimulation techniques, protocols, and clinical outcomes. RESULTS A broad range of neuromodulation strategies and protocols were identified and assessed. Improved postoperative GI recovery following electrical stimulation was reported by 55% of studies (10/18), most commonly those assessing transcutaneous electrical nerve stimulation and electroacupuncture therapy (7/10). Several studies reported shorter time to first flatus and stool, shorter duration of hospital stay, and reduced postoperative pain. However, inconsistent reporting and limitations in trial design were common, compromising a definitive determination of electrical stimulation efficacy. CONCLUSIONS Electrical stimulation appears to be a promising methodology to aid postoperative GI recovery, but greater attention to mechanisms of action and clinical trial quality is necessary for progress. Future research should also aim to apply validated and standardized gut recovery outcomes and consistent neuromodulation methodologies.
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Affiliation(s)
- James A Penfold
- Faculty of Medical and Health Sciences, Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Cameron I Wells
- Faculty of Medical and Health Sciences, Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Ian P Bissett
- Faculty of Medical and Health Sciences, Department of Surgery, The University of Auckland, Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand
| | - Gregory O'Grady
- Faculty of Medical and Health Sciences, Department of Surgery, The University of Auckland, Auckland, New Zealand.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Department of Surgery, Auckland District Health Board, Auckland, New Zealand
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O'Grady G, Angeli TR, Paskaranandavadivel N, Erickson JC, Wells CI, Gharibans AA, Cheng LK, Du P. Methods for High-Resolution Electrical Mapping in the Gastrointestinal Tract. IEEE Rev Biomed Eng 2018; 12:287-302. [PMID: 30176605 DOI: 10.1109/rbme.2018.2867555] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the last two decades, high-resolution (HR) mapping has emerged as a powerful technique to study normal and abnormal bioelectrical events in the gastrointestinal (GI) tract. This technique, adapted from cardiology, involves the use of dense arrays of electrodes to track bioelectrical sequences in fine spatiotemporal detail. HR mapping has now been applied in many significant GI experimental studies informing and clarifying both normal physiology and arrhythmic behaviors in disease states. This review provides a comprehensive and critical analysis of current methodologies for HR electrical mapping in the GI tract, including extracellular measurement principles, electrode design and mapping devices, signal processing and visualization techniques, and translational research strategies. The scope of the review encompasses the broad application of GI HR methods from in vitro tissue studies to in vivo experimental studies, including in humans. Controversies and future directions for GI mapping methodologies are addressed, including emerging opportunities to better inform diagnostics and care in patients with functional gut disorders of diverse etiologies.
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Opportunities and Challenges for Single-Unit Recordings from Enteric Neurons in Awake Animals. MICROMACHINES 2018; 9:mi9090428. [PMID: 30424361 PMCID: PMC6187697 DOI: 10.3390/mi9090428] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/17/2018] [Accepted: 08/23/2018] [Indexed: 12/18/2022]
Abstract
Advanced electrode designs have made single-unit neural recordings commonplace in modern neuroscience research. However, single-unit resolution remains out of reach for the intrinsic neurons of the gastrointestinal system. Single-unit recordings of the enteric (gut) nervous system have been conducted in anesthetized animal models and excised tissue, but there is a large physiological gap between awake and anesthetized animals, particularly for the enteric nervous system. Here, we describe the opportunity for advancing enteric neuroscience offered by single-unit recording capabilities in awake animals. We highlight the primary challenges to microelectrodes in the gastrointestinal system including structural, physiological, and signal quality challenges, and we provide design criteria recommendations for enteric microelectrodes.
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