Flagship 3: Diagnosis and therapy of gastric dysrhythmias

Principal Investigators

Associate Professor Leo Cheng, University of Auckland
Professor John Windsor, University of Auckland

Associate Investigators

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

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.

Serosal electrodes.

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.

Three graphs showing dysrhythmic slow wave activity from a gastroparesis patient.

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.

Photos of laparoscopic and endoscopic electrodes (left/right).

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

Seed project 5: A Model-assisted Diagnostic Package for Clinical Electrogastrography (EGG) is a complementary project led by Dr. Peng Du. As part of this seed project, the team will develop system and techniques to transform the efficacy of electrical recordings obtained on the skin surface. An accurate analysis of electrogastrography provides a completely non-invasive method of recording gastric bioelectrical activity, for patients with acute and chronic digestive conditions.

Photo showing a torso tank for EGG studies.