Genes and the development of obesity
6 Jul, 2007 01:36 pm
Obesity is one of the main health problems of our times, and it is estimated that it concerns nearly 300 million people in the world. Furthermore, the number of obese people is increasing. In the United States alone, the number of obese adults has increased by 10% in the last 10 years.
The causes of obesity are multiple and poorly understood, but certainly includes behavioral, social and genetic factors. Genes play a significant role on the development of obesity. Elucidating the genetic and molecular mechanisms by which high caloric diet induces obesity is critical for the understanding of this condition and for the development of new treatment for it.
A new scientific study from the Mayo Clinic (Rochester, MN, USA) explores the mechanism of high caloric diet-induced obesity in mice.
Genetic linkage studies indicate a correlation between chromosome 4 near marker D4S403 where the CD38 gene is located, and the development of a clustering of disease conditions including obesity, diabetes and high cholesterol.
A new study in laboratory animals from Doctors at the Mayo Clinic (USA) has shown that CD38 plays a critical role on the development of obesity and some of its deleterious effects. CD38 regulates energy metabolism in cells and by this mechanism it can alter the activity of the enzyme SIRT1. SIRT1 has received major attention in the recent years since it appears to be the enzyme responsible for increase in longevity observed with caloric restriction and treatment with resveratrol, a compound found in red wine that increase longevity and can prevent obesity in mice. In the recent published work by our group the role of CD38 as a regulator of SIRT1, energy metabolism and obesity, was explored. Our main hypothesis is that CD38 by regulating intracellular levels of NAD and SIRT1 plays a crucial role on the development of obesity. In lay terms CD38 may be a new gene responsible for the development of obesity, since when the CD38 gene is turned off (knock out) mice are resistant to become obese even when feed with a high caloric fat diet.
Although this new study further advances our knowledge on the genetic mechanisms of obesity the main cause of this condition in humans can still be explain by lack of exercise and high caloric diets. It is possible that in the future these new genetic discoveries may help the development of new drugs for the treatment of the deleterious effects of obesity. However, a heath life style that includes diet and exercise are still the best weapons we have to fight obesity.
Reference:
Maria Thereza P. Barbosa, et al, The enzyme CD38 (a NAD glycohydrolase, EC 3.2.2.5) is necessary for the development of diet-induced obesity, The Faseb Journal Online, June 21, 2007
This paper links the CD38 gene in obesity by demonstrating that mice lacking the gene display resistance to diets that promote obesity in normal mice. Such studies provide further evidence for the polygenetic control of obesity in animals.