A 2-compartment stochastic model of HSC behavior.
Each HSC in the hemopoietic stem-cell reserve may by chance replicate (resulting in a second, identical HSC in this compartment), undergo apoptosis, or differentiate. These fates are probabilistic (stochastic) and occur at mean rates of λ, α, and ν, respectively. An HSC that commits to a differentiation and maturation program initiates a clone that contributes to hemopoiesis until exhaustion (the mean rate of clone exhaustion is μ). R is the number of HSCs in the stem-cell reserve. R0 is the number of HSCs in the stem-cell reserve at time zero, ie, the number of transplanted HSCs. C is the number of contributing clones andC0 is the number of contributing clones immediately after transplantation. Although individual HSC decisions are modeled as random or stochastic and are independent in terms of probability theory, the rates at which the different decisions happen in the HSC compartment are density dependent.1
