In the study, mature male rats immunized 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 hormone ghrelin, has shown the potential, in animal models at least, to put an end to that risky and often futile struggle.
The scientists believe these findings may mark a turning point in the treatment of obesity by confirming the effectiveness of immunopharmacotherapy to combat this serious and growing global problem. Immunopharmacotherapy engages the immune system, specifically antibodies, to bind to selected targets, directing the body’s own immune response against them. This approach is being tested in a number of other areas including drug addiction.
“Our study is the first published evidence proving that preventing ghrelin from reaching the central nervous system can produce a desired reduction in weight gain,” noted Dr Kim Janda, a senior author of the paper and a professor of chemistry at Scripps Research.
“We’re not claiming that our study answers the question of obesity treatment once and for all,” Dr Janda continued. “What we are saying – and what our study confirms – is that this looks like a serious workable solution to the problem. And while much more research is needed to understand the full therapeutic potential of immunopharmacotherapy in combating obesity, these initial results are extremely positive.”
According to recent reports from the World Health Organization, about one billion people worldwide are overweight or obese, most of them in the developed world.
The ghrelin vaccine produced by Scripps Research scientists is not the only one being tested. Swiss biotech firm Cytos is currently testing a ghrelin-based vaccine in a combined phase I/II study with 112 obese patients. Like the Scripps Research vaccine, Cytos’ vaccine produces antibodies that inhibit the uptake of ghrelin by the brain. However, there are several differences between the two vaccines, Scripps Research scientists have pointed out.