ROCHESTER, Minn. -- A new implantable medical device, developed in collaboration with Mayo Clinic researchers, shows promise as a reversible and less extreme alternative to existing bariatric surgeries, according to findings published in the current issue of the journal Surgery.
Laparoscopic surgery places electrodes into the abdomen. The control unit is under the skin. This treatment is much more reversible than gastric bypass. People who had the therapy done lost weight.
In a six-month open label trial involving three medical centers in Australia, Mexico and Norway, the 31 obese participants who received the vagal nerve blocking device, also called VBLOCTM vagal blocking therapy, lost an average of nearly 15 percent of their excess weight. A quarter of the participants lost more than 25 percent, and three patients lost more than 30 percent.
15% of one's excess weight doesn't sound like so much. But without knowing the absolute amount of weight loss it is hard to judge. Also, will the weight loss continue?
The interesting thing about this approach is that it amounts to playing games to fool one's nervous system.
Michael Camilleri, M.D., is a gastroenterologist who helped design the study and one of the Mayo Clinic researchers whose previous work and know-how contributed to development of the device in collaboration with EnteroMedics, Inc. Dr. Camilleri says the goal is to find a less drastic alternative to bariatric surgery that will still yield significant weight loss. Bariatric surgery techniques include "banding" -- placement of a band around the top part of the stomach to reduce its capacity -- or bypass procedures which reroute food and remove part of the stomach.
"For this study, we wanted to get an initial assessment of whether blocking the vagus nerve electrically could cause obese patients to feel full after a normal-sized meal," Dr. Camilleri explains. "Patients were not put on any restricted diets or given counseling that typically accompanies gastric banding or bypass. We wanted to determine how much weight loss could be attributed to the device alone."
Dr. Camilleri says VBLOC therapy is similar to a heart pacemaker, but instead of stimulating a normal, regular heartbeat, it uses high-frequency electricity to block the nerve impulses between the brain and the stomach and pancreas. A pacemaker continuously monitors the heart and regulates its beating. But the patient flips a switch to activate the VBLOC device when the system is worn during the daytime hours so that the blocking signal can influence how the stomach functions and food is digested following a meal.
With conventional stomach bypass some of the weight loss comes from a reduction in the level of the hunger hormone ghrelin. Does this VBLOC therapy reduce the amount of ghrelin in the bloodstream? If so, does it reduce ghrelin as much as bypass surgery does? A method short of surgery that reduced the amount of ghrelin in the bloodstream would offer a lot of advantages in terms of avoided sometimes deadly complications from surgery and also avoided costs of surgery and recovery.
|Share |||Randall Parker, 2008 June 27 09:01 PM Brain Appetite|