Anti-obesity molecule promises to help fat cells burn more energy
One of the more promising avenues in recent obesity research has beenthe investigation into the remarkable energy-burning characteristicsof a specific type of fat, called brown fat. A new study fromresearchers at the University of Cambridge has excitingly discovereda blood-based molecule that can both increase the amount of brown fatin the body and activate its calorie-burning processes.
Most of the fat inour bodies is known as white fat, which forms our internal caloric storagesystem. However, we also hold a second kind of adipose tissue,referred to as brown fat. This type of fat is rich in mitochondriaand holds a great deal more blood vessels than regular white fat,allowing it to burn energy at an incredibly high rate.
Brown fat isimportant in regulating body temperature and is designed to jump intoaction when an animal gets cold, hence its prominence in hibernatinganimals. In humans brown fat is found abundantly in babies but untilrecently it was thought to disappear in older adults as white fattakes over with aging.
Breakthrough research in 2009 revealed brown fat to notonly be present in adult humans, but also still active. Thisdiscovery supercharged obesity research into hunting for ways to turnwhite fat brown, and while several impressive studies have foundtechniques that can trigger the conversion, this may be only half ofthe problem. It is one thing to simply increase the volume of brown fat in a body, but it is a completely different challenge to find ways to activate calorie burning in that fat.
"There have been a lot of studies that have found molecules thatpromote brown fat development, but simply increasing the amount ofbrown fat will not work to treat disease – it has to be able to getenough nutrients and be turned on," explains lead author on the newstudy, Toni Vidal-Puig.
Vidal-Puig and the University of Cambridge team have been workingon ways to activate brown fat for several years. In 2012 theresearchers revealed the discovery of a molecule called BMP8b. Mousestudies showed this molecule effectively triggering brown fat'senergy-burning mechanisms, and when the gene for BMP8b was deletedfrom the animals the brown fat essentially ceased functioning.
The new research set out to investigate what effect increasinglevels of BMP8b would have on the volume and activity of brown fat inmice. The impressive results revealed that upping the levels of BMP8bactually made white fat browner, a process occasionally referred to as beiging. Perhaps even more importantly though was the discoverythat increasing BPM8b resulted in a larger volume of blood vesselsand nerve activity in white fat. This suggests the molecule iseffective at not only converting white fat to brown, but also helpingestablish the environment the cells need to effectively burn energy.
Sam Virtue, co-author on the new study, uses an automotive analogyto explain how important this molecule may be to solving the brownfat/white fat problem.
"It's like taking a one liter engine outof a car and sticking in a two liter engine in its place," saysVirtue. "In theory the car can go quicker, but if you only have a tinyfuel pipe to the engine and don't connect the accelerator pedal itwon't do much good. BMP8b increases the engine size, and fits a newfuel line and connects up the accelerator!"
At this stage the technique has only been effectively demonstrated inmice, so much more work needs to be done before any kind ofanti-obesity treatment is delivered. But, the hypothesis ispromising, as BMP8b is found in the blood of humans, suggesting itcould be manipulated to stimulate brown fat activity. The next stepfor the research is to begin investigating BMP8b in humans.
The new study was published in the journal Nature Communications.
Source: University of Cambridge