1
|
Drake CE, Cheng LK, Muszynski ND, Somarajan S, Paskaranandavadivel N, Angeli-Gordon TR, Du P, Bradshaw LA, Avci R. Electroanatomical mapping of the stomach with simultaneous biomagnetic measurements. Comput Biol Med 2023; 165:107384. [PMID: 37633085 DOI: 10.1016/j.compbiomed.2023.107384] [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: 03/27/2023] [Revised: 07/17/2023] [Accepted: 08/14/2023] [Indexed: 08/28/2023]
Abstract
Gastric motility is coordinated by bioelectric slow waves (SWs) and dysrhythmic SW activity has been linked with motility disorders. Magnetogastrography (MGG) is the non-invasive measurement of the biomagnetic fields generated by SWs. Dysrhythmia identification using MGG is currently challenging because source models are not well developed and the impact of anatomical variation is not well understood. A novel method for the quantitative spatial co-registration of serosal SW potentials, MGG, and geometric models of anatomical structures was developed and performed on two anesthetized pigs to verify feasibility. Electrode arrays were localized using electromagnetic transmitting coils. Coil localization error for the volume where the stomach is normally located under the sensor array was assessed in a benchtop experiment, and mean error was 4.2±2.3mm and 3.6±3.3° for a coil orientation parallel to the sensor array and 6.2±5.7mm and 4.5±7.0° for a perpendicular coil orientation. Stomach geometries were reconstructed by fitting a generic stomach to up to 19 localization coils, and SW activation maps were mapped onto the reconstructed geometries using the registered positions of 128 electrodes. Normal proximal-to-distal and ectopic SW propagation patterns were recorded from the serosa and compared against the simultaneous MGG measurements. Correlations between the center-of-gravity of normalized MGG and the mean position of SW activity on the serosa were 0.36 and 0.85 for the ectopic and normal propagation patterns along the proximal-distal stomach axis, respectively. This study presents the first feasible method for the spatial co-registration of MGG, serosal SW measurements, and subject-specific anatomy. This is a significant advancement because these data enable the development and validation of novel non-invasive gastric source characterization methods.
Collapse
Affiliation(s)
- Chad E Drake
- 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, TN, USA
| | | | | | | | | | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
| |
Collapse
|
2
|
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.
Collapse
Affiliation(s)
- Raj Makwana
- Blizard Institute, Queen Mary University of London, UK
| | | |
Collapse
|
3
|
Makwana R, Crawley E, Straface M, Palmer A, Gharibans A, Devalia K, Loy J, O'Grady G, Andrews PLR, Sanger GJ. Synergistic augmentation of rhythmic myogenic contractions of human stomach by arginine vasopressin and adrenaline: Implications for the induction of nausea. Br J Pharmacol 2022; 179:5305-5322. [PMID: 36068676 PMCID: PMC9826163 DOI: 10.1111/bph.15943] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 08/30/2022] [Accepted: 09/02/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE Nausea is associated with the hormonal secretion of vasopressin and adrenaline, although their actions in inducing nausea is poorly understood. Here, we have investigated their actions on human stomach muscle. EXPERIMENTAL APPROACH Muscle strips were suspended in tissue baths and neuronal-/non-neuronally-mediated contractions were measured. Custom software analysed eight motility parameters defining spontaneous phasic non-neuronally mediated contractions. Receptor distributions were assessed by qPCR and immunofluorescence. KEY RESULTS V1A receptors and α1 -adrenoceptors were located on muscle as well as interstitial cells of Cajal (ICCs). Myogenic contractions of human proximal and distal stomach (respectively, 2.6 ± 0.1 and 2.7 ± 0.0 per minute; n = 44) were larger in the distal area (1.1 ± 0.1 and 5.0 ± 0.1 mN), developing relatively slowly (proximal) or rapidly (distal). Vasopressin caused tonic (proximal) or short-lived (distal) increases in muscle tone and increased myogenic contraction amplitude, frequency and rate (acting at V1A receptors; thresholds 10-11 -10-10 M); by contrast, cholinergically mediated contractions were unaffected. Oxytocin acted similarly to vasopressin but less potently, at OT receptors). Adrenaline increased (10-10 -10-5 M; α1 -adrenoceptors) and decreased (≥10-6 M; β-adrenoceptors) muscle tone and enhanced/reduced myogenic contractions. Cholinergically mediated contractions were reduced (α2 -adrenoceptors). Combined, vasopressin (10-9 M) and adrenaline (10-8 M) increased muscle tone and phasic myogenic activity in a synergistic manner. CONCLUSIONS AND IMPLICATIONS Vasopressin and adrenaline increased human gastric tone and myogenic contraction amplitude, rate of contraction and frequency. In combination, their actions were further increased in a synergistic manner. Such activity may promote nausea.
Collapse
Affiliation(s)
- Raj Makwana
- Blizard Institute, Faculty of Medicine and DentistryQueen Mary University of LondonLondonUK
| | - Ellie Crawley
- Blizard Institute, Faculty of Medicine and DentistryQueen Mary University of LondonLondonUK
| | - Marilisa Straface
- Blizard Institute, Faculty of Medicine and DentistryQueen Mary University of LondonLondonUK
| | - Alexandra Palmer
- Blizard Institute, Faculty of Medicine and DentistryQueen Mary University of LondonLondonUK
| | - Armen Gharibans
- Department of Surgery and Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand
| | - Kalpana Devalia
- Bariatric Surgery DepartmentHomerton University HospitalLondonUK
| | - John Loy
- Bariatric Surgery DepartmentHomerton University HospitalLondonUK
| | - Greg O'Grady
- Department of Surgery and Auckland Bioengineering InstituteUniversity of AucklandAucklandNew Zealand
| | | | - Gareth J. Sanger
- Blizard Institute, Faculty of Medicine and DentistryQueen Mary University of LondonLondonUK
| |
Collapse
|
4
|
O'Grady G, Gharibans AA, Du P, Huizinga JD. The gastric conduction system in health and disease: a translational review. Am J Physiol Gastrointest Liver Physiol 2021; 321:G527-G542. [PMID: 34549598 DOI: 10.1152/ajpgi.00065.2021] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Gastric peristalsis is critically dependent on an underlying electrical conduction system. Recent years have witnessed substantial progress in clarifying the operations of this system, including its pacemaking units, its cellular architecture, and slow-wave propagation patterns. Advanced techniques have been developed for assessing its functions at high spatiotemporal resolutions. This review synthesizes and evaluates this progress, with a focus on human and translational physiology. A current conception of the initiation and conduction of slow-wave activity in the human stomach is provided first, followed by a detailed discussion of its organization at the cellular and tissue level. Particular emphasis is then given to how gastric electrical disorders may contribute to disease states. Gastric dysfunction continues to grow in their prevalence and impact, and while gastric dysrhythmia is established as a clear and pervasive feature in several major gastric disorders, its role in explaining pathophysiology and informing therapy is still emerging. New insights from high-resolution gastric mapping are evaluated, together with historical data from electrogastrography, and the physiological relevance of emerging biomarkers from body surface mapping such as retrograde propagating slow waves. Knowledge gaps requiring further physiological research are highlighted.
Collapse
Affiliation(s)
- Gregory O'Grady
- Department of Surgery, The University of Auckland, 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.,Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Jan D Huizinga
- Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
5
|
Sclocco R, Nguyen C, Staley R, Fisher H, Mendez A, Velez C, Kettner NW, Kuo B, Napadow V. Non-uniform gastric wall kinematics revealed by 4D Cine magnetic resonance imaging in humans. Neurogastroenterol Motil 2021; 33:e14146. [PMID: 33797166 DOI: 10.1111/nmo.14146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 02/24/2021] [Accepted: 03/16/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Assessment of gastric function in humans has relied on modalities with varying degrees of invasiveness, which are usually limited to the evaluation of single aspects of gastric function, thus requiring patients to undergo a number of often invasive tests for a full clinical understanding. Therefore, the development of a non-invasive tool able to concurrently assess multiple aspects of gastric function is highly desirable for both research and clinical assessments of gastrointestinal (GI) function. Recently, technological advances in magnetic resonance imaging (MRI) have provided new tools for dynamic (or "cine") body imaging. Such approaches can be extended to GI applications. METHODS In the present work, we propose a non-invasive assessment of gastric function using a four-dimensional (4D, volumetric cine imaging), free-breathing MRI sequence with gadolinium-free contrast enhancement achieved through a food-based meal. In healthy subjects, we successfully estimated multiple parameters describing gastric emptying, motility, and peristalsis propagation patterns. KEY RESULTS Our data demonstrated non-uniform kinematics of the gastric wall during peristaltic contraction, highlighting the importance of using volumetric data to derive motility measures. CONCLUSIONS & INFERENCES MRI has the potential of becoming an important clinical and gastric physiology research tool, providing objective parameters for the evaluation of impaired gastric function.
Collapse
Affiliation(s)
- Roberta Sclocco
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Gastroenterology, Harvard Medical School, Center for Neurointestinal Health, Massachusetts General Hospital, Boston, MA, USA.,Department of Radiology, Logan University, Chesterfield, MO, USA
| | - Christopher Nguyen
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Rowan Staley
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Gastroenterology, Harvard Medical School, Center for Neurointestinal Health, Massachusetts General Hospital, Boston, MA, USA
| | - Harrison Fisher
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - April Mendez
- Department of Gastroenterology, Harvard Medical School, Center for Neurointestinal Health, Massachusetts General Hospital, Boston, MA, USA
| | - Christopher Velez
- Department of Gastroenterology, Harvard Medical School, Center for Neurointestinal Health, Massachusetts General Hospital, Boston, MA, USA
| | - Norman W Kettner
- Department of Radiology, Logan University, Chesterfield, MO, USA
| | - Braden Kuo
- Department of Gastroenterology, Harvard Medical School, Center for Neurointestinal Health, Massachusetts General Hospital, Boston, MA, USA
| | - Vitaly Napadow
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Logan University, Chesterfield, MO, USA
| |
Collapse
|
6
|
Sukasem A, Cakmak YO, Khwaounjoo P, Gharibans A, Du P. The effects of low-and high-frequency non-invasive transcutaneous auricular vagal nerve stimulation (taVNS) on gastric slow waves evaluated using in vivo high-resolution mapping in porcine. Neurogastroenterol Motil 2020; 32:e13852. [PMID: 32281229 DOI: 10.1111/nmo.13852] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/25/2020] [Accepted: 03/19/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUNDS Gastric motility is regulated by an electrophysiological activity called slow-wave and neuronal innervations by the vagus nerve. Transcutaneous auricular vagal nerve stimulation (taVNS) has been demonstrated to have therapeutic potential for a wide range of medical conditions, including the management of gastric dysfunctions. The main objective of this study was to gain a better understanding of how non-invasive neuromodulation influences gastric slow wave under in vivo conditions. METHODS TaVNS protocols were applied in conjunction with 192-channel gastric bioelectrical mapping in porcine subjects under general anesthesia. The spatiotemporal profiles of gastric slow wave were assessed under two different taVNS protocols at 10 and 80 Hz. KEY RESULTS The taVNS protocols effectively altered the interval and amplitude of gastric slow waves, but not the velocity or the percentage of spatial dysrhythmias. In the subjects that responded to the protocols, the 10 Hz protocol was shown to normalize slow-wave propagation pattern in 90% of the subjects, whereas the 80 Hz protocol was shown to inhibit slow waves in 60% of the subjects. CONCLUSIONS AND INFERENCES Chronic responses of gastric motility and slow waves in response to taVNS should be investigated using non-invasive means in conscious subjects in future.
Collapse
Affiliation(s)
- Atchariya Sukasem
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Yusuf Ozgur Cakmak
- Department of Anatomy, The University of Otago, Dunedin, New Zealand.,Centre For Health Systems and Technology, The University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, The University of Otago, Dunedin, New Zealand
| | | | - Armen Gharibans
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Department of Surgery, The University of Auckland, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.,Department of Engineering Science, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
7
|
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
| |
Collapse
|
8
|
Du P, Grady GO, Paskaranandavadivel N, Tang SJ, Abell T, Cheng LK. High-resolution Mapping of Hyperglycemia-induced Gastric Slow Wave Dysrhythmias. J Neurogastroenterol Motil 2019; 25:276-285. [PMID: 30870879 PMCID: PMC6474709 DOI: 10.5056/jnm18192] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/27/2018] [Accepted: 01/16/2019] [Indexed: 12/11/2022] Open
Abstract
Background/Aims It is now recognised that gastric dysrhythmias are best characterised by their spatial propagation pattern. Hyperglycemia is an important cause of gastric slow wave dysrhythmia, however, the spatiotemporal patterns of dysrhythmias in this context have not been investigated. This study aims to investigate the relationship between hyperglycemia and the patterns of dysrhythmias by employing high-resolution (multi-electrode) mapping simultaneously at the anterior and posterior gastric serosa. Methods High-resolution mapping (8 × 16 electrodes per serosal) was performed in 4 anesthetized hounds. Baseline recordings (21 ± 8 minutes) were followed by intravenous injection of glucagon (0.5 mg per dose) and further recordings (59 ± 15 minutes). Blood glucose levels were monitored manually using a glucose sensing kit at regular 5-minute intervals. Slow wave activation maps, amplitudes, velocity, anisotropic ratio, and frequency were calculated. Differences were compared between baseline and post glucagon injection. Results Baseline slow waves propagated symmetrically and antegrade. The blood glucose levels were increased by an average of 112% compared to the baseline by the end of the recordings. All subjects demonstrated elevated incidence of slow wave dysrhythmias following injection compared to the baseline (48 ± 23% vs 6 ± 4%, P < 0.05). Dysrhythmias arose simultaneously or independently on anterior and posterior serosa. Spatial dysrhythmias occurred before and persisted after the onset and disappearance of temporal dysrhythmias. Conclusions Infusion of glucagon induced gastric slow wave dysrhythmias, which occurred across a heterogeneous range of patterns and frequencies. The spatial dysrhythmias of gastric slow waves were shown to be more prevalent and persisted over a longer period of time compared to the temporal dysrhythmias.
Collapse
Affiliation(s)
- Peng Du
- 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
| | | | | | | | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Surgery, Vanderbilt University, Nashville, TN, USA
| |
Collapse
|
9
|
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.
Collapse
|
10
|
Du P, Calder S, Angeli TR, Sathar S, Paskaranandavadivel N, O'Grady G, Cheng LK. Progress in Mathematical Modeling of Gastrointestinal Slow Wave Abnormalities. Front Physiol 2018; 8:1136. [PMID: 29379448 PMCID: PMC5775268 DOI: 10.3389/fphys.2017.01136] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/22/2017] [Indexed: 12/19/2022] Open
Abstract
Gastrointestinal (GI) motility is regulated in part by electrophysiological events called slow waves, which are generated by the interstitial cells of Cajal (ICC). Slow waves propagate by a process of "entrainment," which occurs over a decreasing gradient of intrinsic frequencies in the antegrade direction across much of the GI tract. Abnormal initiation and conduction of slow waves have been demonstrated in, and linked to, a number of GI motility disorders. A range of mathematical models have been developed to study abnormal slow waves and applied to propose novel methods for non-invasive detection and therapy. This review provides a general outline of GI slow wave abnormalities and their recent classification using multi-electrode (high-resolution) mapping methods, with a particular emphasis on the spatial patterns of these abnormal activities. The recently-developed mathematical models are introduced in order of their biophysical scale from cellular to whole-organ levels. The modeling techniques, main findings from the simulations, and potential future directions arising from notable studies are discussed.
Collapse
Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Stefan Calder
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Timothy R. Angeli
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Shameer Sathar
- 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
| | - Leo K. Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Surgery, Vanderbilt University, Nashville, TN, United States
| |
Collapse
|
11
|
|
12
|
Du P, O'Grady G, Paskaranandavadivel N, Tang SJ, Abell T, Cheng LK. Reply. Exp Physiol 2017; 102:135. [DOI: 10.1113/ep086141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- P. Du
- University of Auckland; Auckland New Zealand
| | - G. O'Grady
- University of Auckland; Auckland New Zealand
| | | | - S. J. Tang
- University of Mississippi Medical Center; Jackson MS USA
| | - T. Abell
- University of Louisville; Louisville KY USA
| | - L. K. Cheng
- University of Auckland; Auckland New Zealand
| |
Collapse
|