Critical Limb Ischemia (CLI) is the most severe form of peripheral arterial disease. It is a highly prevalent condition with suboptimal therapeutic options. One third of CLI patients are not suitable for surgical revascularization - these 'no-option' patients have substantial morbidity and mortality and frequently have diabetes mellitus. Hence, new treatments are urgently required. Mesenchymal Stem Cells (MSCs) are a novel and exciting potential for inducing therapeutic angiogenesis. However, MSCs are heterogeneous in nature and the angiogenic potential of different clonal populations from the same donor is currently unknown. We hypothesize that MSC heterogeneity will allow for the isolation of clonal cell populations with enhanced angiogenic potential. These populations may have enhanced therapeutic potential and may also be of interest in exploring the mechanism of MSC-induced angiogenesis.