Hunger

The hormone ghrelin, made partly by the cells lining the upper stomach, calls out to us to eat. Could a procedure that may reduce its production allow us to lose weight? (Tracy Boulian / Samuel Goldwyn Films / April 16, 2004)

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A medical procedure that treats bleeding in the upper gastrointestinal tract has an unexpected - and, for some patients, quite welcome - side effect: It makes them lose weight. That procedure, called left gastric artery embolization, may just be the next big thing in the fight against obesity. And as a new study demonstrates, it does seem to work.

In gastric artery embolization, an interventional radiologist threads a catheter up (or down, depending on his or her entry point) to the left gastric artery and deposits a slew of tiny beads to reduce the flow of blood to the gastric fundus, the upper part of the stomach. With its blood supply limited, scientists believe, the upper stomach area cuts back its production of the hormone ghrelin, which is the stomach's signal that it's empty and needs filling.

Along with cells in the pancreas, the cells lining the fundus of the stomach are the body's principal suppliers of the powerful hunger-signaling peptide, ghrelin. In recent years, physicians have observed that patients who had the procedures done tended to lose weight afterward; as evidence of ghrelin's role in appetite mounted, some began to surmise that the weight loss was the result of reduced ghrelin circulating in these patients' bloodstreams following the procedure.

A team of researchers set out to test whether physicians' observations were indeed right, and their findings are to be presented at the annual meeting next week of the Radiological Society of North America. They combed electronic medical records looking for patients who had undergone a left gastric embolization procedure to stanch gastric hemorrhage, and for a comparison group of patients who had undergone another embolization procedure of a different artery for the same complaint. Their subjects had to have had their weight measured within two weeks prior to the procedures, and within three months after.

In all, they compared 15 patients who had embolization of the left gastric artery and 18 patients who had had an embolization procedure elsewhere. The team was led by Massachusetts General Hospital radiologist Rahmi Oklu. Oklu is a liver cancer expert, and the procedure is also widely used to treat the side effects of treatment for advanced liver cancer.

Compared with those who had embolization of a different artery, patients who had their left gastric artery blocked dropped from an average weight of 189.1 to 174.5 pounds, a 7.9% decrease in body weight. Those whose embolization targeted other vessels went from an average weight of 164.7 to 162.8 pounds, a 1.2% loss of body weight.

Left gastric artery embolization is considered a one-day procedure -- a far simpler undertaking than most bariatric surgery. Only much more research will tell whether the weight loss it induces is, in fact, a result of reduced ghrelin production, and whether the body over time compensates for the changes the embolization procedure brings in its wake. The procedure's safety for patients who are healthy but obese is also still far from established.

"These findings may lead to a role for the interventional radiologist in the treatment of obesity," Oklu says in notes for the presentation.

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