"In terms of computational expertise, the BIO group can make
a major
contribution to the experimental field that explores
the mechanisms
underlying obesity-related disorders," says
Ilpo Vattulainen.
The Biological Physics and Soft Matter Group (BIO) at TUT has taken part in a project that revealed that obesity triggers a transformation in fat cells. The findings can help prevent diseases associated with obesity.
"People who store most of their fat around their waist are at risk of developing metabolic syndrome. The condition commonly precedes the development of type 2 diabetes and other health problems related to obesity. The purpose of the project was to pinpoint the cellular changes that underlie the development of metabolic syndrome," describes Professor Ilpo Vattulainen.
The project was overseen by Professor Matej Oresic from the VTT Technical Research Centre of Finland.In addition to researchers at TUT, the Obesity Research Unit supervised by MD, PhD Kirsi Pietiläinen at Helsinki University Central Hospital and Professor Antonio Vidal-Puig's research group at the University of Cambridge were involved in the project.
The approach was to collect samples of adipose tissue, or body fat, from various sets of identical twins. In each twin pair, one was overweight but not morbidly obese while the other had a normal body mass index. Since identical twins share the same DNA, the weight differences were due to diet and lifestyle choices.
The researchers took biopsies of fat tissue from each twin and analysed the lipid content and composition of the samples.
After the lipids were analysed, Vattulainen's group created atomic-level models of the investigated fat cells. Changes in the lipid composition were modelled using computer simulations.
The research results demonstrated that obesity triggers changes in fat cell membranes that make fat tissue susceptible to inflammation and alter the physical properties of cell membranes.
"Cell membranes are primarily composed of lipids and are normally flexible and fluid. However, as fat cells grow, their lipid content starts to change. Our findings suggest that these changes are actually an adaptation that serves to preserve flexibility and the essential functions of proteins that are attached to cell membranes."
Fat cells of an obese person (left) and a person with a normal body mass index (right).
Photos: Kirsi Pietiläinen.
"However, this compensatory mechanism cannot be maintained indefinitely. It breaks down in those who are morbidly obese, leading to changes in the physical properties of cell membranes and gradually cell malfunction," says Vattulainen.
What induces inflammatory changes in fat tissue? Can the abnormal lipid composition be restored to normal by losing weight? Why do others stay healthy and others not?
Vattulainen's group will continue pursuing research in the field.
"In terms of computational expertise, the BIO group can make a major contribution to the field that explores the mechanisms underlying obesity-related disorders. One of our strategic priority areas is research into lipoproteins. It has important implications for public health," says Ilpo Vattulainen.
Further information:
Biological Physics and Soft Matter Group (BIO)
"While obesity brings serious health risks, a few extra pounds are not harmful. People should not go overboard with dieting," says Ilpo Vattulainen.
"Instead of looking at body mass index, people should monitor the amount of fat they carry. And remember that a certain amount of fat is essential to bodily functions. Fat serves as an energy reserve, cushions internal organs and regulates body temperature. In addition to white fat, our bodies contain brown fat that produces heat but otherwise still remains poorly understood," adds Vattulainen.
