Obesity increases one's risk of developing certain diseases, such as cancer, heart disease, and stroke. The symptoms of these diseases don't always lie in areas where extra fat has accumulated. In fact, the diseases often manifest in areas distant from the fat. An international group of scientists now identified changes that occur in almost all tissues in response to obesity.
The results further confirm that obesity is a systematic condition. More specifically, it's a condition of systemic inflammation. Identifying the biological processes behind obesity can help researchers find potential tissue-specific targets to treat obesity.
In conducting the study, the researchers set out to find the connection between obesity and gene expression in 44 tissue types. The tissue types included brain and internal organ tissue, which are rarely accessible to study in large sample sizes. However, for this study, the researchers used the GTEx dataset of tissues. This dataset contains thousands to tissue samples from autopsy donors. The study is the first to explore the simultaneous changes in tissue function in response to obesity in so many different body systems.
“Interestingly, the changes in tissue function appeared to be only partially shared between different types of tissues," said Taru Tukiainen, a postdoctoral researcher at the Institute for Molecular Medicine in Finland. Some tissues responded in pairs, either enhancing or undermining the function of the other. Adipose tissue and adrenal glands are a clear example of tissues responding together. Both are organs that secrete hormones essential to metabolism. However, when reacting to changes in BMI, they act in “completely opposite ways,” Tukiainen said. For example, adipose tissues exhibit a decrease in metabolic activity, while adrenal glands exhibit an increase in metabolic activity.
The researchers hope scientists will use their data to find ways to prevent and treat serious complications of obesity. "An association between two variables does not necessarily imply there is a causal link,” Tukiainen said. So, at this time, the researchers are unable to tell from the gene expression results alone which drives which. "We can, however, address the potential causes by using genetic variants known to be associated with BMI in combination with our data on gene expression," Tukiainen said.
The researchers have presented their research today at the annual European Society of Human Genetics conference.
Source: European Society of Human Genetics via EurekAlert!