Discovery may revolutionize methods of weight loss
An international team at Georgetown University, headed by a Polish doctor, has discovered that long-term stress can generate weight gain.That is the opposite of the weight loss that short-term stress can induce.Professor Zofia Zukowska?s team also identified the biological mechanism that precipitates weight gain in the face of long-term stress, the Polish Press Agency (PAP) reported. The discovery, published on the web site of the journal ?Nature Medicine,? could revolutionize human cosmetic and reconstructive plastic surgery. It could also lead to better control of the combination of risk factors ? known as metabolic syndrome ? that increase a patient?s chances of developing heart disease, stroke and diabetes.?Nature Medicine,? the premier journal for biomedical research, said mice exposed to long-term stress grew fat and developed hypertension and diabetes. The stress included exposing them to an aggressive mouse or making them stand in a puddle of cold water an hour a day for two weeks. Georgetown said researchers also discovered the biological mechanism through which stress activates weight gain in mice. They called it a neuro-chemical pathway ? and they said they were able to manipulate it.It may explain why people who are chronically stressed gain more weight than they should, based on the calories they consume. The pathway involves a neuropeptide NPY neurotransmitter and a neuropeptide Y2R receptor. The neurotransmitter, which is produced under stress, increases fat storage. The neurotransmitter regulates the daily rhythm of the body, sexual functions and appetite. It also increases the activity of noradrenalin and regulates the immune system?s reaction to infections. Physical activity, stress and contact with high-frequency electricity increase the production of NPY.The researchers learned that blocking NPY?s ability to get to the receptors prevented fat storage and encouraged speedy weight loss. After they applied the blocker for two weeks, the mice?s cells started to lose weight. ?We couldn?t believe such fat remodeling was possible, but the numerous different experiments conducted over four years demonstrated that it is, at least in mice,? said Zukowska, the study?s senior author. Zukowska, who holds both medical and Ph.D. degrees, is chair of the Department of Physiology and Biophysics at Georgetown University Medical Center.?We are hopeful that these findings might eventually lead to control of metabolic syndrome, which is a huge health issue for many Americans,? she added. ?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.? ?This is the first study to show that stress has a direct effect on fat accumulation, body weight and metabolism,? said Lydia Kuo, a medical student whose work on the study helped her earn her Ph.D. in physiology. ?In humans, this kind of stress-mediated fat gain may have nothing to do with the brain, and is actually just a physiological response of their fat tissue,? she said. ?Perhaps the most rapid clinical application of these results will be in both cosmetic and reconstructive plastic surgery,? said another author of the study, Dr. Stephan Baker, an associate professor of plastic surgery at Georgetown University Hospital. The ability to add fat as a graft would be useful in facial rejuvenation, breast surgery, buttock and lip enhancement and facial reconstruction, he said. And using injections like those tested in the study could make fat grafts inexpensive, biocompatible and permanent. ?This is the first well-described mechanism found that can effectively eliminate fat without using surgery,? he said. ?A safe, effective, non-surgical means to eliminate undesirable body fat would be of great benefit to our patients.? ?Although we don?t expect that, in the future, a person will be able to eat everything he or she wants, chase it down with a Y2R blocking agent, and end up looking like a movie star, we are encouraged that these findings could improve human health,? Zukowska said. The study was funded by National Institutes of Health grants awarded to Zukowska, an American Heart Association Predoctoral Mid-Atlantic Fellowship to Kuo, and grants from the National Institutes of Health and the Plastic Surgery Educational Foundation to Baker.