Two bone substitutes analyzed in vitro by porcine and human adipose-derived stromal cells

Nowadays, the repair of large bone defects is an important goal in orthopaedic and dental fields. Tissue engineering, applied to increase the bone regeneration process, combines suitable scaffolds with either terminally differentiated cells or Mesenchymal Stromal Cells. In vitro studies with Adipose-derived Stromal Cells (ASCs) may identify new bioactive supports, to be tested in preclinical model. In this study, we evaluated the biocompatibility and the osteoinductive properties of two bone substitutes, RegenOSS (RO-1) and a new generation scaffold (RO-2), on both porcine and human ASCs. Porcine ASCs need a prolonged initial phase to adapt to both substitutes; indeed, their growth was initially reduced respect to cells cultured in their absence. In contrast, human ASCs were not negatively affected. However, no toxicity of RO-1 and -2 was observed on both ASC populations which are able to stick to both biomaterials. RO-1 and -2 supported osteogenic differentiation of porcine and human ASCs in a different manner: the presence of RO-1 up-regulated both alkaline phosphatase (ALP) activity and collagen production of human ASCs, whereas in porcine ASCs, RO-2 seemed to up-regulate ALP activity, while the production of collagen is mainly stimulated by the presence of RO-1. We suggest to use not just human ASCs, but also animal ones to select suitable scaffolds to generate bio-constructs in vitro, which then need to be tested in animal model before reaching the market.