Modeling the architecture and dynamics of hematopoiesis

Hematopoiesis is a multistep process that results in the production of a variety of blood cells with different morphologies and diverse functions. All of these cells have their origin in hematopoietic stem cells (HSCs) that replicate slowly to selfrenew and give rise to progeny cells that proceed along the path of differentiation. The process is complex with the cells responding to a wide variety of cytokines and growth factors. We discuss a model of hematopoiesis based on stochastic cell behavior. Multiple compartments are introduced to keep track of each cell division process and increasing differentiation. Despite its simplicity, the model is able to account for the salient features of hematopoiesis and is compatible with considerable and independent experimental data. The model is applicable to hematopoiesis across mammals and can be used to understand the dynamics of various disorders both in humans and in animal models.