Chemical liposuction: fat-reducing injection success in primates
A fat-reducing drug, Adipotide, that can reverse obesity in monkeys has been successfully tested by US scientists.
The agent, which was injected daily over a four week study period into a group of naturally obese baboons, macaques and rhesus primates, contains of a short string of amino acids that cause the drug to lock selectively onto the walls of blood vessels that supply adipose tissue. Linked to this short, blood vessel-targeting protein sequence is a further chemical signal that causes cells that are exposed to it to commit suicide. This it achieves by triggering structures called mitochondria, which are essential energy-generating components inside cells, to break down. In this way the agent causes the chemical equivalent of liposuction, culling fat cells and causing weight loss.
Compared control animals, the treated monkeys showed weight reductions of up to 14% and an average fat mass reduction of almost 40%. This translated into a body mass index (BMI) reduction of up to 20% and, just as overweight humans develop an insulin-resistant state that often leads to diabetes, the treated animals showed significantly lower insulin levels afterwards.
Surprisingly, the treated animals showed no signs of altered blood cholesterol or fatty acid levels while receiving the new agent, and there were no obvious behavioural side effects or evidence of altered eating behaviours during the study. The only thing that was picked up during the trial was a trend towards increased urine output and dehydration in animals receiving higher doses of the drug, although the relevance of this finding remains to be shown. The results offer a promising lead in the development of treatments to combat global obesity, which now affects up to one in five adults in many developed countries and carries a cancer risk elevation equivalent to being a regular smoker.
According to co-author Renata Pasqualini, "Development of this compound for human use would provide a non-surgical way to actually reduce accumulated white fat, in contrast to current weight-loss drugs that attempt to control appetite or prevent absorption of dietary fat." The team are now about to commence a human clinical trial involving a 28-day administration of the agent to patients with prostate cancer to determine whether their disease improves alongside the ensuing weight loss.