Bone Abstracts

The clinical orthopaedic problem of delayed healing or non-union after complex fractures affects 5–10% of all patients, especially within the elderly population. Recently several in vitro studies showed that CD133+ cells bare angiogenic capacities and contribute to a better outcome concerning ischemia induced angiogenesis in vivo. A local administration of these specific cells to the fracture gap appears feasible as a new treatment option for biological impaired fracture healing.

We analyzed availability, angiogenic and osteogenic properties of CD133+ cells derived from peripheral blood of healthy young and aged, male and female probands in vitro to answer the question whether cells obtained from aged patients bare the same regenerative potential as cells from young donors. For this purpose flow cytometric measurements, co-cultures with endothelial cells and osteogenic differentiation assays together with mesenchymal stroma cells were performed. The regenerative capacities of CD133+ cells were also investigated in vivo in an aged animal model with biological impaired fracture healing.

The experiments confirmed that CD133+ cells contain high angiogenic capacities. We also observed that the quantity of CD133+ cells increases twofold in aged people, making them an even more attractive target for intra-operative transplantation. The positive effect of local CD133+ cell transplantation could also be revealed in vivo by an enhanced bone tissue formation accompanied by a twofold increased bone mineral content. The improved bone regeneration went along with a threefold elevated development of new blood vessels within the fracture site.

Aiming to identify a new source for cells utilizable for cell therapy, we could prove that CD133+ mononuclear cells derived from peripheral blood feature bone regenerative capacities. Thus, an application of these cells to fracture sites is a promising approach for the treatment of impaired fracture healing.