Justin Rochford, Anke Roelofs & Cosimo De Bari

Fat cells labelled by a red fluorescent protein specifically expressed in the stem cell population we are investigatingIt is well known that obesity is bad for you. However, this isn’t because the fat tissue itself is always bad. In fact it is normally an important safe store for nutrients in the body. In obesity, fat tissue has been pushed to the limit and can no longer grow to store more energy coming from the diet. As a result the nutrients, particularly fats (lipids) and sugar, go to other organs instead where they don’t belong, preventing them from working normally and causing diseases such as diabetes and heart disease.

We now know that fat tissue in different parts of the body, and the fat cells it is made from, can behave very differently. Some fat cells are beneficial, for instance by protecting organs from lipid accumulation, whereas others are associated with metabolic disease and are harmful. Fat cells are made from stem cells and it is really important to work out which stem cells make which fat cells. If we could find ways to make more of the good fat cells, and less of the bad, this could make a big difference to health.

In this work, we have found a new type of stem cell that only makes certain fat cells and not others. This includes the fat found in the joints as well as other specific places in the body. At the moment, we know very little about these fat cells and what they might do in diseases caused by obesity and conditions that affect the joints, such as osteoarthritis.

We want to find out exactly what fat tissue these stem cells make and work out if it is good or bad. This will tell us whether they could be used in stem cell therapy, or if we could use drugs to make more or less of only these fat cells. This could be an exciting new treatment, either for people who can’t make fat properly, people with joint disease, or for overweight people who need fitter, healthier fat cells.