Flagship 3: Diagnosis and therapy of gastric dysrhythmias

Summary

Contractions of the smooth muscle in the gastrointestinal (GI) tract are regulated and coordinated by electrophysiological events known as slow waves. Despite outstanding potential to treat significant functional GI motility diseases, the clinical use of GI electrophysiological measurements remains in its infancy. This is in stark comparison with the cardiac field, where electro-anatomical mapping, ablation and pacemakers are routinely performed to manage rhythm disorders constituting a multi-billion dollar industry.

Members of Flagship 3 have been instrumental in developing the tools and techniques that have allowed the discovery of complex spatial GI electrical dysrhythmias (see figure below) associated with functional gastric motility disorders (e.g., gastroparesis and chronic unexplained nausea and vomiting). Patients suffering from such disorders lead a poor quality of life and often have symptoms such as chronic nausea, bloating and vomiting.

As the slow wave dysrhythmias in these patients often occur at frequencies similar to the frequency of normal activity, the use of high-resolution spatial recordings provide critical information that can easily be missed with sparse recordings that often only analyse frequency dynamics.

An example of the tools and techniques that have allowed the discovery of complex spatial GI electrical dysrhythmias.

However, existing techniques are highly invasive and the electrodes require direct access to the serosal (outside) surface of the stomach (see figure below). As such, these methods can only be employed in intraoperative studies at a limited number of centres.

To address these limitations, we will develop and validate new technologies that are less invasive and can be routinely used clinically for assessing the functional state of a patient with gastric motility disorders. In particular, we will develop systems for characterising gastric slow wave activity during (i) laparoscopic surgery and (ii) endoscopy.

The team will also work closely with major US based hospitals that treat patients with functional motility disorders, on pre-clinical validation studies.

Team

Principal Investigators

University of Auckland

Associate Investigators

  • Dr Timothy Angeli
  • Dr Peng Du
  • Professor Richard Gearry
  • Dr Gregory O’Grady
  • Dr Niranchan Paskaranandavadivel
  • Dr Shameer Sathar

Our Work

Collaborators

  • University of Auckland (New Zealand)
  • University of Otago (New Zealand)
  • Mayo Clinic (USA)
  • Washington and Lee University (USA)
  • FlexiMap Ltd (New Zealand)

Publications

  1. Patterns of Abnormal Gastric Pacemaking After Sleeve Gastrectomy Defined by Laparoscopic High-Resolution Electrical Mapping
  2. Loss of Interstitial Cells of Cajal and Patterns of Gastric Dysrhythmia in Patients With Chronic Unexplained Nausea and Vomiting
  3. Concerning the Validity of Gastrointestinal Extracellular Recordings
  4. Multi-channel Wireless Mapping of Gastrointestinal Serosal Slow Wave Propagation
  5. Gastric Arrhythmias in Gastroparesis: Low- and High-resolution Mapping of Gastric Electrical Activity
  6. A Multiscale Tridomain Model for Simulating Bioelectric Gastric Pacing
  7. The Impact of Surgical Excisions on Human Gastric Slow Wave Conduction, Defined by High-resolution Electrical Mapping and In Silico Modeling
  8. Measuring Gastrointestinal Electrical Activity With Extracellular Electrodes
  9. Slow Wave Conduction Patterns in the Stomach: from Waller's Foundations to Current Challenges
  10. Characterization of Electrophysiological Propagation by Multichannel Sensors
  11. Diabetic Gastroparesis Alters the Biomagnetic Signature of Gastric Slow Wave
  12. Simultaneous Anterior and Posterior Serosal Mapping of Gastric Slow Wave Dysrhythmias Induced by Vasopressin
  13. Iterative Covariance-based Removal of Time-Synchronous Artifacts: Application to Gastrointestinal Electrical Recordings
  14. Acute Slow Wave Responses to High-Frequency Gastric Electrical Stimulation in Patients With Gastroparesis Defined by High-Resolution Mapping
  15. Functional Physiology of the Human Terminal Antrum defined by High-resolution Electrical Mapping and Computational Modeling
  16. High-resolution Electrical Mapping of Porcine Gastric Slow-wave Propagation from the Mucosal Surface
  17. A Novel Retractable Laparoscopic Device for Mapping Gastrointestinal Slow Wave Propagation Patterns
  18. Time-Delay Mapping of High-Resolution Gastric Slow-Wave Activity
  19. Restoration of Normal Colonic Motor Patterns and Meal Responses after Distal Colorectal Resection
  20. The Virtual Intestine: In silico Modeling of Small Intestinal Electrophysiology and Motility and the Applications
  21. A Theoretical Analysis of Electrogastrography (EGG) Signatures Associated with Gastric Dysrhythmias