Newly identified factors cause adipose tissue to malfunction in the presence of excess fat and may play a role in obesity-related disorders, report researchers from Finland (Pietilainen KH et al. PLoS Biol. 2011;9:e1000623). Adipose tissue, the main storage site for excess body fat, has a finite capacity to expand. Once this limit is exceeded, lipids are deposited in organs such as the liver, muscle, and pancreas, causing metabolic disease.
In the study, an analysis of the lipid composition of adipose tissue in pairs of monozygotic twins in which one twin was lean and the other obese but still metabolically healthy showed that composition of membrane phospholipids differed between the lean and obese twins. The researchers hypothesized that in obese individuals, changes in membrane lipid composition may be an adaptation to adipose tissue expansion that occurs to preserve the physical properties and function of the membranes. However, this protection comes with the cost of increasing vulnerability to inflammation, which can lead to metabolic disorders such as high blood pressure and diabetes.