Munich based scientists have yesterday, February 29, 2016, announced a research success which explains and helps battle the yoyo dieting effect. A team of researchers at the Technical University of Munich (TUM), the Helmholtz Zentrum München (HMGU) and the German Center for Diabetes Research (DZD) has identified a new mechanism that regulates the effect of the satiety hormone leptin. The study published in the journal ‘Nature Communications’ identified the enzyme HDAC5 as key factor in our control of body weight and food intake and potential target against the Yoyo dieting effect.
Why do we get fat and why is it so difficult for so many people to keep off excess weight? A team of researchers headed by Prof. Dr. Matthias Tschöp (Helmholtz Diabetes Center at HMGU and Metabolic Diseases Chair at TUM) and Dr. Paul Pfluger (Research Unit Neurobiology of Diabetes at HMGU) now identified a new component in the complex fine-tuning of body weight and food intake. They found that the enzyme histone deacetylase 5 (HDAC5) has a significant influence on the effect of the hormone leptin. This hormone plays a crucial role in triggering satiety and thus on how the body adapts to a changing food environment.
Pfluger describes the results as follows: "HDAC5 is an important link in the communication between our fat tissue and hunger centers in the brain." Initial experiments have shown that the production and activity of HDAC5 in our control center for energy balance, the hypothalamus, is increased by a high-fat diet, by enlarged fat deposits and by the satiety hormone leptin. Dhiraj Kabra, first author of the study, added: "HDAC5 is a molecular switch in the brain that helps the body to recognize how full the fat depots are. Without HDAC5, we cannot adapt our food intake or curb our fat deposition."
Disruption of the Signalling Pathway Leads to Obesity
According to the scientists, mice unable to produce HDAC5 respond significantly worse to leptin – a condition referred to as leptin resistance. They show a continuously increased food intake and – in comparison to mice with intact HDAC5 – show increased obesity, i.e. they get fat. Through targeted activation of HDAC5 the team was able to reverse this effect, and thereby enabling obese animals to loose fat mass and body weight.
"The restoration of leptin sensitivity is an important step on the path towards sustainable weight loss and towards combating potential sequelae of obesity such as type 2 diabetes," said study leader Pfluger. "In addition to the essential changes in diet and exercise behaviour, in the future the individual components of the leptin effect could be potential drug targets to support the weight loss process." One of these essential components – HDAC5 – has already been identified. "However," Pfluger concluded, "it remains to be seen in the coming years whether this enzyme will be a suitable target for combating obesity in humans."
Leptin is secreted by fat tissue in direct correlation to body fat mass, thereby signalling to neurons in the brain that the fat stores are full. This leads to a negative energy balance whereupon the body reduces food intake, which ultimately leads to a reduction of body weight and fat storage. As a consequence, in the reduced fat stores less leptin is released, food intake is increased, and the fat stores and body weight are increased. If you understood everything until here, you can find further info at the website of the Technical University of Munich.