From heterogeneity to plasticity in adipose tissues: site-specific differences

In mammals, two types of adipose tissues are present, brown (BAT) and white (WAT). WAT itself can be divided into subcutaneous and internal fat deposits. All these tissues have been shown to present a great tissue plasticity, and recent data emphasized on the multiple differentiation potentials obtained from subcutaneous WAT. However, no study has compared the heterogeneity of stroma-vascular fraction (SVF) cells and their differentiation potentials according to the localization of the fat pad. This study clearly demonstrates that WAT and BAT present different antigenic features and differentiation potentials. WAT by contrast to BAT contains a large population of hematopoietic cells composed essentially of macrophages and hematopoietic progenitor cells. In WAT, the non-hematopoietic population is mainly composed of mesenchymal stem cell (MSC)-like but contains also a significant proportion of immature cells, whereas in BAT, the stromal cells do not present the same phenotype. Internal and subcutaneous WAT present some discrete differences in the phenotype of their cell populations. WAT derived SVF cells give rise to osteoblasts, endothelial cells, adipocytes, hematopoietic cells, and cardiomyoblasts only from inguinal cells. By contrast, BAT derived SVF cells display a reduced plasticity. Adipose tissues thus appear as complex tissues composed of different cell subsets according to the location of fat pads. Inguinal WAT appears as the most plastic adipose tissue and represents a potential and suitable source of stem cell, considering its easy sampling as a major advantage for cell therapy.