In the new study,mature male rats immunised with specific types of the active vaccine ate normally yet gained less weight and had less body fat, indicating that the vaccine directly affects the body's metabolism and energy use.
This finding may be especially important to stop what is commonly known as "yo-yo dieting,"the cycle of repeated loss and regain of weight experienced by many dieters. The new vaccine,which is directed against the harmone ghrelin,a naturally occuring harmone thathelps regulate energy balance in the body,has shown the potential, in animal models at least, to put an end to that risky often furtile struggle.
These finding may mark aturning point in the treatment of obesity by confirming the effectiveness of immunopharmacotherapy to combat this serious growing global problem.
Immunopharmacotherapy engages the immune system, specifically antibodies, to bind selected targets, directing the body's own immune response against them. This approach is being tested in the number of other areas including drug addiction, especially addiction to cocaine and nicotine.
"The study shows our vaccine slows weight gain and decreases stored fat in rat,"said the senior author of the paper Kim jnda, who is Ely R. Callaway, Jr.professor of Chemistry at Scripps Research, amember of The Skaggs Institute for Chemical Biology,and Director of the Worm Institute of Research and Medicine.
"While food intake was unchanged in all testing groups, those who were gien the most effective vaccine gained the least amount of weight. To have an impact on apetite and weight gain, ghrelin first has to move from the bloodstream into the brain-where,over long periods, it simulates the retention of a level of stored energy as fat. Our study is the first published evidence proving that preventing ghrekin from reaching the central nervous system can produce a desired reduction in weight gain."
Ghrelin, a gastic endocrine harmone produced primarily in the stomach, plays a physiological role in energy homeostasis, although the full extent of that role remains unknown. It was first identified in 1999 as a naturally occuring ligand-a molecule that binds to another to form a larger molecular complex-for a natural growth harmone secretagogue receptor.
What is known is that ghrelin promotes weight gain and fat storage through its metabolic actions, decreasing the breakdown of stored at for energy as well as crubing energy expenditure itself. During periods of weight loss, such as dieting, the body produces high levels of ghrelin to slow down fat metabolism, encourage eating, and promote fat retention, changes which normally make it difficult to lose weight and keep it off.