In what they have called a "stunning research advance," scientists at Georgetown University Medical school have remodeled body fat in mice using local injections:
In the paper, the Georgetown researchers describe a mechanism they found by which stress activates weight gain in mice, and they say this pathway -- which they were able to manipulate -- may explain why people who are chronically stressed gain more weight than they should based on the calories they consume.
This pathway involves two players -- a neurotransmitter (neuropeptide Y, or NPY) and the receptor (neuropeptide Y2 receptor, or Y2R) it activates in two types of cells in the fat tissue: endothelial cells lining blood vessels and fat cells themselves. In order to add fat selectively to the mice they tested, researchers injected NPY into a specific area. The researchers found that both NPY and Y2R are activated during stress, leading to apple-shape obesity and metabolic syndrome. Both the weight gain and metabolic syndrome, however, were prevented by administration of Y2R blocker into the abdominal fat.
Pilot data in research with monkeys suggests the operation of a similar mechanism, according to the lead author of the study, Dr. Zofia Zukowska, who added:
"We are hopeful that these findings might eventually lead to control of metabolic syndrome, which is a huge health issue for many Americans," she said. "Decreasing fat in the abdomen of the mice we studied reduced the fat in their liver and skeletal muscles, and also helped to control insulin resistance, glucose intolerance, blood pressure and inflammation. Blocking Y2R might work the same way in humans, but much study will be needed to prove that."