Scientists have identified a drug that can help people with genetic obesity lose weight by inhibiting their appetite.
Around two to six per cent of all people with obesity have mutations in one of their 'appetite genes'. This gives them a strong genetic predisposition for developing obesity, also called monogenic obesity. Their experience of hunger is overruling and their feeling of satiety limited.
Such people respond less well to existing obesity treatments. Diets and surgery can help them lose weight, but the long-term effect is poor, as they are unable to maintain the weight loss.
Researchers at the University of Copenhagen in Denmark have discovered that this group of people with obesity can lose weight with the help of the medicine liraglutide, which is a modified form of the appetite-inhibiting hormone GLP-1 naturally secreted from the intestine when we eat. "They feel less hungry and lose six per cent of their body weight within four months," said Signe Sorensen Torekov, who led the study published in the journal Cell Metabolism.
Researchers examined 14 persons with obesity caused by pathogenic mutations in the so-called MC4R gene and 28 persons with obesity without the mutations. Both groups were treated with the medicine for four months; no changes were made to their diet and level of exercise in this period.
The individuals with this most common form of monogenic obesity lost 7 kilogrammes of their body weight compared to 6 kilogrammes for the people with common obesity.
"Many researchers have believed that the function of the medicine was mainly to inhibit the appetite by stimulating this specific appetite receptor in the brain which does not work in this particular group of people with obesity," said Torekov. "However, our study shows that the medicine still has an appetite-inhibiting effect and thus must affect the appetite in a different way," he said.
Medicine acting as an analogue to our natural GLP-1 hormone is already available. The study makes it possible to treat the most common form of genetically caused obesity, where patients respond poorly to existing treatments.