This is a reprint from The Gathered View, courtesy of PWSA (USA).
Obesity and problems with overeating can be influenced by a number of factors in the brain. One such factor is brain-derived neurotrophic factor (BDNF), which is involved in eating and energy regulation. BDNF is found in the brain in the cortex, the hippocampus, and the basal forebrain and it helps brain cells survive and grow. Low levels of BDNF have been linked to depression, dementia, schizophrenia, Obsessive-Compulsive Disorder, Alzheimer’s Disease and Huntington’s Disease.
Unger and colleagues have recently explored the role of BDNF in energy regulation and eating behaviors by giving normal mice injections of glucose (sugar) and measuring the amount of BDNF in a brain region that is know to be important for these processes, the Ventromedial Hypothalamus (VMH) (Selective Deletion of Bdnf in the Ventromedial and Dorsomedial Hypothalamus of Adult Mice Results in Hyperphagic Behavior and Obesity , The Journal of Neuroscience, 2007). They found that glucose leads to an increase in BDNF, indicating that when the body gets enough sugar and is full, it signals the brain to make BDNF.
Next, they wanted to see if taking BDNF out of an adult animal’s brain could affect eating behaviors and obesity as it has been shown to do in fetal and very young mice. Removing BDNF from the VMH and another important brain region, the Dorsomedial Hypothalamus (DMH), caused them to eat more and become obese. Thus, BDNF normally signals when to stop eating.
This study showed for the first time that BDNF in the adult brain is important for energy balance. If further studies can continue to confirm the role of BDNF in obesity and overeating problems, this factor may be added to the list of factors important for understanding and managing the weight and hyperphagia problems in individuals with PWS. The mechanisms of overeating involve (to name a few) leptin, insulin, melanocortins, noradrenaline, dopamine, serotonin, and the gut hormone ghrelin. There is likely not one singular factor or protein in the brain that causes the complex eating behaviors and subsequent complications seen in those with PWS, but the study of BDNF may be the next step in better understanding the complexity of energy regulation in PWS.