Size of fat cells can cause metabolic disorders

Why are overweight people more susceptible to illness?

Obesity can be caused by many things: by a genetic predisposition, an unhealthy diet, lack of exercise, a slow metabolism, mental health conditions or the use of certain medications. People with obesity often not only encounter stigmatization by society; they are also likely to suffer from reduced quality of life and a greater risk of secondary diseases. They face a higher incidence, for example, of type 2 diabetes, cardiovascular diseases and various cancers.

But why do people have such an increased tendency to illness when they put on weight? Dr. Julius Honecker and Professor Hans Hauner from the Chair of Nutritional Medicine took a closer look at this question. They were supported in this by the Research Group “Experimental Magnetic Resonance Imaging” led by Professor Dimitrios Karampinos from the Department of Diagnostic and Interventional Radiology of the TUM University Hospital rechts der Isar, and by the lab of Professor Melina Claussnitzer,  an institute member at the Broad Institute of MIT and Harvard and assistant professor at Massachusetts General Hospital and Harvard Medical School.

Although the connection between being overweight and being more susceptible to illness has long since been recognized, so far little is known about the importance of fat cell size. The team was now able to show that gene expression – to what extent which genetic information is being used - in adipose tissue is associated with fat cell size and that changes in gene expression in enlarged fat cells are likely to be responsible for the development of metabolic diseases.

“Large fat cells have a significantly altered metabolism and promote among other things the development of type 2 diabetes and cardiovascular diseases,” says Professor Hauner. “This is important evidence that the function of fat cells varies considerably depending on their size.”