The development could offer an alternative for people unwilling to undergo more invasive treatments such as gastric bypass surgery, or who do not respond well to weight-loss drugs, the researchers said.
“The basic concept is we can have this balloon that is dynamic, so it would be inflated right before a meal and then you wouldn't feel hungry. Then it would be deflated in between meals,” said Giovanni Traverso, an associate professor of mechanical engineering at MIT, a gastroenterologist at Brigham and Women’s Hospital, and the senior author of the study detailed in Device.
Approved for use in the United States, saline filled gastric balloons stimulate a sense of fullness in the stomach, and studies have shown that they work well, but the benefits are often temporary.
“Gastric balloons do work initially. Historically, what has been seen is that the balloon is associated with weight loss. But then in general, the weight gain resumes the same trajectory,” Traverso said in a statement. “What we reasoned was perhaps if we had a system that simulates that fullness in a transient way, meaning right before a meal, that could be a way of inducing weight loss.”
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To achieve a longer-lasting effect in patients, the researchers considered a device that could expand and contract on demand, which led to two prototypes. One is a traditional balloon that inflates and deflates, and the other a mechanical device with four arms that expand outward, pushing out an elastic polymer shell that presses on the stomach wall.
In animal tests, the researchers found that the mechanical-arm device could effectively expand to fill the stomach, but they opted to pursue the balloon option.
“Our sense was that the balloon probably distributed the force better, and down the line, if you have balloon that is applying the pressure, that is probably a safer approach in the long run,” said Traverso.
The researchers’ new balloon is like a traditional gastric balloon, but it is inserted into the stomach through an incision in the abdominal wall. The balloon is connected to an external controller that can be attached to the skin and contains a pump that inflates and deflates the balloon when needed. Inserting this device would be like the procedure used to place a feeding tube into a patient’s stomach.
“If people, for example, are unable to swallow, they receive food through a tube like this. We know that we can keep tubes in for years, so there is already precedent for other systems that can stay in the body for a very long time. That gives us some confidence in the longer-term compatibility of this system,” said Traverso.
In tests in animals, the researchers found that inflating the balloon before meals led to a 60 per cent reduction in the amount of food consumed. These studies were done over the course of a month, but longer-term studies are planned to see if this reduction leads to weight loss.
“The deployment for traditional gastric balloons is usually six months, if not more, and only then you will see good amount of weight loss. We will have to evaluate our device in a similar or longer time span to prove it really works better,” said lead author Neil Zixun Jia.
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