The Department of Biomedicine

BBB seminar: Jørn V. Sagen

Human brown fat and improvement in metabolic health

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Jørn V. Sagen
Hormone Laboratory, Bergen Stem Cell Consortium (BSCC), Haukeland University Hospital, and KG Jebsen Center for Diabetes Research and Department of Clinical Science, University of Bergen

The prevalence of obesity has reached epidemic proportions and is a major contributor to the development of type 2 diabetes mellitus (T2D), cardiovascular disease and certain types of cancer. Today bariatric surgery (“obesity surgery”) has been proven to be a very effective long-term approach for weight reduction. At the Hormone laboratory we have developed a general biobank (Vestnorsk forskningsbiobank for overvekt – VFO) where we in collaboration with the hospitals at Voss, Førde, and Haugesund collect adipose tissue from bariatric patients. This biobank has been of most importance for studying changes in adipose tissue after weight loss, demonstrating the importance of biobanks in medical research.

This biorepository also contains cells isolated from liposuction material. Here we are able to isolate adipose-derived mesenchymal multipotent stem cells which can be differentiated into mature adipocytes. Adipose tissue is a complex organ formed by various cell types, of which adipocytes are the most abundant. There are three types of adipocytes, white, beige and brown fat cells. White adipocytes store energy as triglycerides (lipids) when caloric intake is in excess, whereas brown fat cells utilise lipids and glucose to dissipate energy into heat, which helps maintaining body temperature in the cold environment. Moreover, the third cell type, beige or brite adipocyte, can, similarly to brown fat cells, be stimulated to convert fat into heat. The stimulated brown fat cells also release factors or adipokines that probably work in both a paracrine as well as an endocrine fashion, thereby improving peripheral insulin sensitivity.

In one of our projects we want to develop in vitro models of brown and beige fat cells originating from adipose-derived stem cells, and study mechanisms that increase their energy utilisation. Also, we aim to identify specific factors released by the activated brown and beige fat cells that have positive effects on whole body metabolism. By studying the biology of brown and beige fat cells we also have an opportunity to develop new therapeutic strategies against obesity and T2D.

Chairperson: Tilo Wolf Eichler, BSCC