THURSDAY, Dec. 4 (HealthDay News) -- Lining the upper small intestine with an impermeable sleeve may be as effective as invasive gastric bypass surgery to help people lose weight and avoid diabetes, a new report says.

The procedure, tested on rats by the Massachusetts General Hospital Weight Center and Gastrointestinal Unit, led to reduced appetite, weight loss and a return to a normal glucose levels.

"This is a clear proof of principle that the human version of this device may be an effective treatment for obesity and diabetes. The clinical device would be placed endoscopically, making it far less invasive than surgical therapies," study leader Dr. Lee Kaplan, director of the MGH Weight Center, said in a hospital news release.

Researchers secured a 10-centimeter-long "endoluminal sleeve" at the outlet of the rats' stomach so it blocked the duodenum and upper jejunum, areas of the small intestine where nutrients are sensed and absorbed. Obese and diabetic rats raised on a high-fat diet given the sleeve consumed 30 percent less of that diet and lost 20 percent more weight than their counterparts who did not receive the sleeve. After 16 weeks, the fasting blood glucose levels, insulin levels and oral glucose tolerance of all rats with the sleeve returned to normal levels.

In other tests on lean rats genetically prone to rapid weight gain, rats with and without the sleeve were given access to a high-fat diet. Both groups gained weight, but those with the endoluminal sleeve ate less and weighed 12 percent less than the control group after four weeks.

"A key finding of this study is that the device induced a decrease in food intake as part of its effect and does not act by reducing absorption of nutrients," said Kaplan, who is also an associate professor of medicine at Harvard Medical School. "Like gastric bypass, it appears to change the way that neural and endocrine signals stimulated by nutrients act on their target organs."

The study was published in the journal Obesity.

Kaplan said conducting large-scale controlled trials of the procedure on humans would be the next step.

More information

The American Diabetes Association has more about type 2 diabetes.