Mechanism of Action
In the normal physiological performance the stomach dilates upon food intake, nerve signals are sent via the vagus nerve and via the superior cervical ganglion to the hind brain. This controls satiety and triggers signaling to the hypothalamus, where glucose and fatty acid metabolism are controlled. Recently performed studies have shown that stimulation of the stomach with an electrical stimulus using the DIAMOND (TANTALUS) system implant can induce GI hormone secretion as well as activation and modulation of this normal physiologic pathway.
The DIAMOND system uses an automatic eating detection mechanism to identify when food is being consumed and consequently delivers stimulation signals to the gastric muscle (see figure). Unlike pacing, the stimulation signals are delivered during the refractory period of the action potential, and are therefore synchronized to the natural electrical activity of the gastric muscle, without disrupting it. The stimulation is used to control muscle contractility and induces enhancement of the normal process of activation cascade of vagal afferent signals involved in peripheral signaling to the central nervous system (CNS) for food intake, which in turn leads to increased metabolic activity and early meal cessation. The end result is an enhancement of the body’s response to food intake leading to satiety.
GCM= Gastric Contractility Modulation
Figure: The DIAMOND system delivers its electrical stimulation during the refractory period of the normal action potential. The effect is to increase the amplitude of the contraction force without changing the rate of contractions. This increase in contraction force increases afferent signaling to the central nervous system (CNS) through the vagus and perhaps other nerves.
Lebovitz H.E., “Gastric Contractility Modulation in the Management of Type 2 Diabetes”, Diabetes Management, 2007
Watch Prof. Lebovitz present at the Belgrade Investigator Meeting, October 2010