BGU researchers: How Belly fat can lead to chronic diseases

Fat cells "communicate" with bodily organs and set in motion a variety of risky sicknesses.

By JUDY SIEGEL-ITZKOVICH
obese fat 88 (photo credit: courtesy)
obese fat 88
(photo credit: courtesy)
Having a potbelly usually tells the bearer that he or she should exercise and eat nutritional meals to lose weight - but fat cells in the abdomen have also been found by Ben-Gurion University of the Negev and German researchers to "communicate" with bodily organs and set in motion a variety of risky chronic diseases. The researchers hope that their discovery will lead to finding a way to influence this pathway in reducing the development of diabetes, heart disease and other results of too much abdominal fat. Dr. Assaf Rudich, senior lecturer from BGU's clinical biochemistry department, and colleagues from the University of Leipzig have just published an important paper on this subject in the Endocrine Society's Journal of Clinical Endocrinology and Metabolism. Although it has been known for some time that excessive fat tissue, especially in the belly, is linked with a higher risk for Type 2 diabetes and other diseases, the way this mechanism works has been poorly understood. Rudich and colleagues have now managed to identify a "signaling pathway" involved in intra-abdominal fat, which is most strongly linked to diseases and death. Fat tissue in the overweight and obese is no longer considered simply a storage place for excess calories; it is in fact an active tissue that secretes multiple compounds and communicates with other tissues, such as the the liver, muscles, pancreas and brain. "Normal communication is necessary for optimal metabolism and weight regulation," explains Rudich. "However, in obesity, fat (adipose) tissue becomes dysfunctional, and miscommunicates with the other tissues. This places fat tissue at a central junction in mechanisms leading to common diseases attributed to obesity, like Type 2 diabetes and cardiovascular diseases." The researchers suggest that fat cells become overgrown as they store increasing amounts of fat; this may cause a reduction in the delivery of oxygen to the tissue, causing the inflammation and death of individual cells. In addition, high levels of nutrients such as glucose and fatty acids can also result in increased metabolic demands, and this in itself can cause cellular stress. The BGU and Leipzig teams arranged for the collection of fat tissue samples from people undergoing abdominal surgery. This enabled them to identify the signaling pathway that occurs in belly fat. They compared how much the pathway was activated in people with less abdominal fat than those with much more and discovered that the signaling pathway was more active depending on the amount of fat accumulation in the abdomen. Moreover, the expression of one of the upstream signaling components, a protein called ASK1, predicts whole-body insulin resistance, which is strongly tied to diabetes and cardiovascular disease independent of other traditional risk factors.