Connection between obesity and mitochondria

Scientists at the University of Helsinki have used 49 pairs of identical twins to understand the metabolic changes that can take place in fat tissue as a result of obesity, teasing out some distinct biological processes that were linked to adverse health effects. The study highlights how obesity can affect the performance of mitochondria in our fat cells, which can in turn drive inflammation and a range of obesity-related conditions.

The identical twins share an identical genetic background, often along with many shared life events and family upbringing, they offer scientists a very valuable testbed for researching how environmental factors later in life alone can impact their gene expression. A case in the NASA twins study that compares the genes and biology of twins Mark and Scott Kelly, one of which spent almost a year in space and one of which did not.

The University of Helsinki team applied this methodology to identical twins that were highly discordant for clinical characteristics of obesity, meaning one was heavier than the other. This enabled the team to explore how environmental and lifestyle factors impacted their gene expression, particularly in relation to mitochondria, widely known as the powerhouse of cells.

The team used various analytical tools and biopsies of fat and muscle tissue to gain a picture of genome-wide gene expression in the twins. This showed that mitochondria function in fat tissue was greatly reduced as a result of obesity. The analysis also revealed evidence that these changes in the fat tissue can drive inflammation and many of the biological processes associated with obesity, such as increased fat in the liver and changes to cholesterol, glucose and insulin metabolism. While mitochondria in muscle tissue was also found to be altered, the effects weren’t as profound and weren’t associated with the adverse health effects.