Adipocyte size distribution: Mathematical model of a tissue property

White adipose tissue is in charge of storing excess of energy in form of lipids. The main cells involved in the process – the adipocytes – adapt their sizes up to $200\mu m$ of diameter to accommodate the storage. In addition, their size distribution is bimodal. A previous mathematical model based on lipid fluxes provided size distribution bimodality. However, the variability within cell population was not fully explored. In the previous model, bimodality was considered a consequence of a bistable distribution of cell sizes at equilibrium: meaning that adipocytes had to have two stable sizes. In this study, we first provide a computational method to evaluate equilibria taking into account cells variability. Our results suggest that this variability is key to provide realistic distributions. In addition, we show that size distributions with a proportion of cell with bi-stable profile are not in good agreement with the measurements. We find that mono-stable (i.e. one equilibrium size) profile within the adipose tissue is enough to explain bimodality and to reproduce qualitatively size distribution data. We thus show that bimodality of adipose tissue size distribution does not arise directly from cellular bi-stability but rather from a tissue property.