Obesity vaccines show promise
According to WHO, today every fifth adult in the world has extra pounds, while at least a third of them are obese. Excess weight is an important risk factor for the development of many chronic diseases, including diabetes mellitus, diseases of the cardiovascular system and cancer. Traditional methods of weight loss are diets, pharmacological preparations and physical exercises. However, diets are ineffective, drugs have side effects, and training is not always enough. Surgical removal of subcutaneous fat deposits is also fraught with complications and does not prevent you from gaining the pumped kilograms again. Therefore, experts have high hopes for a fundamentally new approach to combat this problem, which is based on the good old method of vaccination.
Traditional preventive vaccines are used to prevent the spread of infectious diseases, and recently appeared therapeutic vaccines "tune" the immune system to fight existing diseases, such as cancer.
The first version of the obesity vaccine was a drug whose active ingredient is complexes of non–infectious virus-like particles with ghrelin molecules - a hormone that stimulates appetite. Paradoxically, the level of ghrelin in obesity is reduced, but the weight loss that occurs as a result of a decrease in the caloric content of the diet or physical exertion leads to a sharp increase in the production of this hormone.
Vaccine developers from the University of Porto, Portugal, working under the guidance of Dr. Mariana Monteiro, administered an experimental vaccine to mice with normal weight and with an induced diet of obesity. In all vaccinated animals, the formation of anti-grelin antibodies and an increase in the rate of calorie burning were observed. Within 24 hours after the first injection, the amount of food consumed by mice decreased to 82%, and after the final injection – to 50% of the amount of food consumed by animals of the control group. At the same time, the level of expression of another appetite–stimulating hormone, neuropeptide Y, decreased simultaneously in the body of vaccinated mice.
The effect of vaccination persisted for two months, which, when extrapolated to the average life expectancy of a person, corresponds to about 4 years. The results of this work were reported by the authors at the 93rd Annual Congress of the Endocrinology Community ENDO 2011 held in Boston.
Another promising drug is the Somatovac vaccine developed by a small biotech company Braasch Biotech, the introduction of which triggers the production of antibodies against somatostatin, a hormone that restricts the synthesis of growth hormone and insulin–like growth factor I. When vaccinated with this drug in the organisms of various animals (including horses, cows, pigs, mice and dogs), an increase in the levels of the growth hormone releasing factor and growth hormone itself was observed. This was accompanied by an increase in muscle mass and the breakdown of fat deposits. The effect persisted for 2 weeks, after which the levels of the hormones involved decreased to normal values. (An additional bonus was an increase in milk yield in cows by stimulating the synthesis of their own hormones, which eliminates the need for the use of recombinant cow somatotropin – an exogenous hormone that increases milk yield, the use of which in the dairy industry causes a lot of controversy.)
As part of the study on mice with an induced diet, obese animals of the experimental group and the control group were fed food with a fat content 6 times higher than the fat content of conventional rodent feed for 6 weeks before the experiment and throughout the study. By the end of the experiment, the vaccinated animals had gained about 30-40% of the weight gained by the control group mice. It can be assumed that in such conditions, a vaccinated person with a body weight of about 100 kilograms would gain 4-7 kg, and an unvaccinated person would gain 15 kg.
Just like the anti-grelin vaccine, somatovac is positioned as a means for use in combination with lifestyle changes. The developers believe that it is advisable to use it under the careful supervision of doctors for the treatment of obese patients, including those with particularly severe forms, with a body mass index above 30.
A serious advantage of the vaccine produced with the help of recombinant E. coli culture is its low cost. The estimated cost of one dose of somatovac, intended for administration once every 1-2 months, is only 10-20 US dollars. For comparison, an annual course with a similar effect of daily administration of somatotropin – synthetic growth hormone – costs about $ 20,000.
However, like any therapeutic approach, vaccination is not a universal means to combat obesity. Contraindications for its implementation are the absence of the growth hormone gene, immune disorders (HIV, chronic infections) and oncological diseases (growth hormone stimulates the growth of tumors).
Moreover, the development of obesity may have various causes, including infection with adenovirus 36. Therefore, experts emphasize that when selecting optimal methods of treating obesity, it is necessary to take into account the physiological heterogeneity of patients.
The developers also note that somatostatin is a hormone preserved during evolution in all vertebrates, from fish to humans. Therefore, somatovac can also be used to treat obese pets, whose lifestyle and diet, as a rule, coincide with the lifestyle and diet of the owners.
Next year, Braasch Biotech plans to simultaneously submit a request to the U.S. Food and Drug Administration for permission to conduct clinical and veterinary studies of somatovac.
Keith N Haffer's article Effects of novel vaccines on weight loss in diet-induced-obese (DIO) mice is published in the Journal of Animal Science and Biotechnology.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Endocrine News (Obesity Vaccines: A Long Shot?)
10.07.2012