Mesenchymal stem cells (MSC) are a valuable source of multipotent progenitors for regenerative medicine, but may require to be genetically modified to widen their efficacy. For example, overexpression of the angiogenic factor VEGF at controlled levels is an attractive strategy to overcome the crucial bottleneck of graft vascularization and to avoid aberrant vascular growth. Since the regenerative potential of MSC is rapidly lost during in vitro expansion, we developed an optimized technique to achieve high-efficiency retroviral vector transduction of both adipose tissue- and bone marrow-derived MSC (ASC/BMSC) and rapidly select cells expressing desired levels of VEGF with minimal expansion. This platform was then used for various regenerative medicine approaches. The area of application described in this book covers the generation of vascularized osteogenic grafts. The presented data suggests that, even though VEGF over-expression is effective to improve angiogenesis, it has the potential to disrupt bone homeostasis towards excessive degradation. This book is useful to professionals interested in controlled expression of secreted factors, regenerative medicine and bone homeostasis.