Tuesday, October 23, 2007

"Vibrating Mice" Develop Less Fat, Study Shows


A new study in mice could shake up the fight against fat.

Laboratory mice that spent 15 minutes a day on a vibrating platform developed 28 percent less fat than control mice during a recent experiment.

But forget the ads for waistband-jiggling vibration belts guaranteed to "burn away fat." These mice experienced very subtle, almost undetectable, tremors.

Scientists theorize that as the mice developed, the vibrations mimicked muscle activity and induced their stem cells to develop into bone or muscle cells rather than fat cells.

"We're not burning fat or taking fat mice and making them skinny," said lead author Clinton Rubin, a biomedical engineer at the State University of New York, Stony Brook.

"We're taking mice who are growing and ... influencing the decision of stem cells [so that they don't] become fat cells."

The finding came in part from research in human spaceflight. Rubin and colleagues are trying to induce stem cells to become bone cells in order to offset the bone loss that results in zero-gravity space environments.

Rubin has also co-founded a for-profit company, Juvent Medical, that is using a similar concept to treat osteoporosis.

The study will appear this week in the journal Proceedings of the National Academy of Science.

Fighting Fat Before it Appears

The human body needs fat cells, which store food energy for future use.

Most doctors believe that obesity is the result of consuming more calories than a body burns. Recent research suggests that genetics and other factors may also play a role.

Rubin cautions that the study is preliminary and raises as many questions as it answers.

But the possibilities for human weight control are intriguing, and they may include developmental as well as metabolic factors.

"Just imagine a way to keep people from getting fat that is not [only] about how many Oreos they eat or how much they exercise—but about keeping them from forming fat cells in the first place," he said.

No Guilt-Free Solutions

But if the prospect of consequence-free overeating and sloth sounds too good to be true, it probably is, experts say.

"The reason we have those cells is to take [in] excess fat," said Roger Unger, an obesity researcher at the University of Texas Southwestern Medical Center.

"If you inhibit [fat cells] and overeat, you haven't done that person a favor," said Unger, who was not involved in the new research.

"The surplus lipids would end up in organs where you don't want to have surplus lipids—like the heart and the liver."

"People that don't have [as many] fat cells, if they overeat, get very sick—[they get] sicker at a much earlier age than people who first get fat and then develop complications."

Rexford Ahima is a University of Pennsylvania endocrinologist.

"The idea that 'non-strenuous work' can reduce body fat is intriguing; however, the findings have to be interpreted with caution," he said.

Ahima noted that key information regarding the mice's energy expenditure, hormones, and metabolism remains unknown and may have impacted the results.

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