Breakthrough research offers hope for new obesity treatment

December 31, 2015

Bi says the results "made sense," given that NPY has been shown to stimulate eating. The less NPY, the less the rats would eat, his team hypothesized. What was a surprise, however, was what they found after they checked the fat content of rats after death. In the groin area of the NPY rats, researchers discovered not the expected white fat found in adult rats, but the telltale signs of brown fat in its place. They confirmed this change by looking at levels of mitochondrial uncoupling protein-1, or UCP-1, through which brown fat burns to produce heat. They used this protein as a marker to determine that the fat that should have been white was instead brown.

Bi says he believes that the transformation from white to brown fat resulting from NPY suppression may be due to activation of brown fat stem cells contained in white fat tissue. While brown fat seems to vanish in humans as they emerge from infancy, the brown fat stem cells may never disappear and may just become inactive as people age.

Bi says it may be possible to transplant or inject brown fat stem cells under the skin to burn white fat and stimulate weight loss. "Only future research will tell us if that is possible," he says.

This study also shows that low levels of hypothalamic NPY increase spontaneous physical activity, improve blood sugar levels and enhance insulin sensitivity in rats, but it remains undetermined whether this brown fat transformation also contributes to these effects.

Source: hopkinsmedicine/psychiatry/expert_team/faculty/B/Bi.html