Electroceuticals for Mapping and Modulating Gut Activity
Gastrointestinal (GI) motility is coordinated by underlying bio-electrical events known as slow waves. High-resolution (HR) mapping of the slow waves has become a fundamental tool for accurately defining electrophysiological properties in gastroenterology, including dysrhythmias in gastric disorders such as gastroparesis, chronic nausea and unexplained vomiting, and functional dyspepsia. Traditionally, HR mapping is achieved via acquisition of slow waves taken directly from the serosa of fasted subjects undergoing invasive abdominal surgery. As in cardiac electrophysiology, implantable pulse generators (IPGs) have been used for stimulating the stomach. Conventionally, two types of pulses have been applied for potential therapeutic effects: short pulses (high frequency/low energy) and long pulses (low frequency/high energy). Low-energy stimulation is typically delivered with a pulse-width in the order of a few hundred microseconds, at frequencies ranging from 5 to 100Hz, and may improve symptoms such as nausea, vomiting, and bloating. High-energy stimulation (or pacing) is typically delivered with a pulse-width in the order of milliseconds (10-600 ms), at frequencies akin to the natural gastric frequency (i.e., 3 cpm). High-energy stimulation has demonstrated potential to pace slow waves and improve motility. Due to high energy consumption the latter stimulation method has not been widely used. In this talk, Dr. Farajidavar will present novel bioelectronics developed in his lab, and used for HR mapping and modulating of the gut activity in small and large animals. The implantable gastric electrical stimulator devices are designed to modulate the stomach and enteric nervous system through different energy levels. Methodologies to wirelessly power up the implants and recharge them will be also discussed in this talk. Dr. Farajidavar will present the novel techniques that have been developed to implant the system in large animals. Finally, he will discuss the work-in-progress that includes plans to integrate the mapping and modulating technologies into a closed-loop therapy, and to translate the developed technologies to human.