The brain plays a crucial role in our body weight by controlling our eating habits. The gray cells receive the necessary information about the current energy status of the body from insulin, hormones from adipose tissue and many other transmitters. At the symposium “Insulin, Adipokines and the Brain” of the German Center for Diabetes Research (DZD) at the Spring Meeting of the German Diabetes Society (DDG), the focus was on the function of the brain and its neurotransmitters in the pathogenesis of obesity, and as a consequence diabetes. The symposium, which was held in Stuttgart on May 18, 2012 under the auspices of the DZD directors Professor Martin Hrabĕ de Angelis, Helmholtz Zentrum München, and Professor Hans-Ulrich Häring, University of Tübingen, presented the most recent research findings.
Does obesity start in the head?
At the DZD symposium, leading diabetes researchers and neuroscientists sought to answer this question. An audience of more than 450 people listened with great interest to the presentation of the new findings on the role of the brain in metabolism.
Professor Häring underlined the importance of the new approach in diabetes research: “Type 2 diabetes also originates in the head. The brain plays a crucial role in our eating behavior and in associated diseases such as type 2 diabetes.” Hormones and other messenger substances as well as the nervous system constantly send the “gray cells” a status update about the energy reserves and their distribution in the body. According to this information, the brain controls food intake and energy expenditure. A dysregulation in this complex interaction can lead to overeating. The resulting obesity is one of the causes for the development of type 2 diabetes.
“The German Center for Diabetes Research provides great conditions for addressing these complex interdisciplinary research questions,” Prof. Hrabĕ de Angelis pointed out. “Completely new therapy options are opening up for personalized treatment of the patient.
Active fat tissue
Contrary to what scientists have assumed for decades, white adipose tissue not only serves as energy storehouse in the body, but is also actively involved in the regulation of the metabolism. This takes place through the release of a variety of hormones that affect the brain. Among the best known of these neurotransmitters – known as adipokines – is leptin, which inhibits the appetite. In his symposium lecture, Professor Hendrik Lehnert of the University Hospital Schleswig-Holstein, Campus Lübeck presented nesfatin-1 and FGF-1 as additional adipokines besides leptin that influence satiety.
Insulin as satiety factor
Insulin not only has an effect on the muscles, liver and fat tissue, but also on the brain. Professor Andreas Fritsche of the Institute of Diabetes Research and Metabolic Diseases of Helmholtz Zentrum München at the University of Tübingen, a DZD partner institute, explained in his lecture, “Insulin not only lowers blood glucose levels, through its direct effect on specific brain regions it controls metabolism and also human behavior.” After eating, elevated levels of insulin send the “I’m full” signal to the brain, thus putting the brakes on calorie intake. In elderly or obese individuals, insulin no longer has much effect in the brain, and insulin resistance develops. This may be caused by genetic factors, but elevated blood lipid levels may also play a role.
How our diet affects the brain
A high-fat diet induces modifications in brain regions that control the energy balance of the body. In mice, a high-fat diet over multiple days led to inflammatory processes in the hypothalamus, which in turn caused a change in the nerve tissue of these regions. Physical activity led to an improvement. Professor Tschöp from the DZD partner institute Helmholtz Zentrum München said, “Our findings shed new light on the impact of our diet on the brain.”
Re-learning eating behavior
The neuroscientist Professor Niels Birbaumer of the University of Tübingen presented a new approach to treating obese individuals. In his lecture he showed that brain regions responsible for food intake can be controlled by the respective individual. Images displaying the degree of blood flow to specific brain regions are shown to the test subject, and he/she is then rewarded for changes in the blood flow. Thus, almost anyone can learn how to actively influence circulation. Remarkably, obese individuals can better control their brain regions that regulate their desire for food than individuals with normal weight. However, they do not associate this with other brain regions that are involved in eating behavior and thus are not successful in changing their behavior.
The intensive discussions following the presentations illustrate the importance and innovativeness of this topic for diabetes research.
A press release in German language regarding the symposium „Insuline, Adipokines und Brain“ at the Annual Meeting of the German Diabetes Society(DDG) you can find here.
Press photos of the symposium you can find here.