Three-Dimensionally Printed Biphasic Calcium Phosphate Ceramic Substrates as the Sole Inducer of Osteogenic Differentiation in Stromal Vascular Fraction Cells

The stromal vascular fraction (SVF) is a derivate of fat tissue comprising both adipose-derived mesenchymal stem cells and endothelial cells and serves as a promising cell source for engineering vascularized bone tissues. Its combination with osteoconductive biphasic calcium phosphate (BCP) ceramic may represent a point-of-care agent for bone reconstruction. Here we assessed the proliferation and osteogenic differentiation capacities of SVF on 3D printed BCP implants, in comparison with isolated adipose-derived mesenchymal stem cells (AD-MSCs). AD-MSCs and SVF isolated from human donors were seeded on plastic or 3D printed BCP ceramics with sinusoidal or gyroid macrotopography and cultured in the presence or absence of osteogenic factors. Vascular, hematopoietic and MSC surface markers were assessed by flow cytometry whereas osteogenic activity was investigated through alizarin red staining and alkaline phosphatase activity. Osteogenic factors were necessary to trigger osteogenic activity when cells were cultured on plastic, without significant difference observed between the two cell populations. Interestingly, osteogenic activity was observed on BCP implants in the absence of differentiation factors, without significant difference in level activity between the two cell populations and macrotopography. This study offers supportive data for the use of combined BCP scaffolds with SVF in a perspective of a one-step surgical procedure for bone regeneration.