ADHESION AND OSTEOGENIC DIFFERENTIATION OF NON-ADHERENT PROGENITORS FROM ADIPOSE-DERIVED STEM CELLS (napASCs) OVER INTEGRA DERMAL REGENERATION TEMPLATE

INTRODUCTION: Non-adherent progenitors from adipose-derived stem cells (n.a.p.ASCs) represent an upstream lineage of multipotent stem cell progenitors capable of clonal expansion and asymmetric divisions comparable to stem cell spheres observed in breast, thyroid and colon, and, as such, confirm the stemness of cells extracted from lipoaspirate. The identification of napASCs confirms the stem-cell origin of the more differentiated and commonly used adherent mesenchymal stromal cells (MSCs). NapASCs adhesion for differentiation purposes may be useful in tissue engineering. In this study we investigate the feasibility of napASCs adhesion over Integra® dermal regeneration template for cell colonization and differentiation toward the osteogenic lineage. MATERIAL AND METHODS: NapASCs were extracted from adipose tissue from 18 healthy donors following patients written consent. NapASCs were expanded in suspension and plated with Integra® andosteogenic medium containing dexamethasone, beta-glycerophosphate and ascorbic acid. Differentiation to the osteogenic lineage was assessed by presence of alkaline phosphatase (ALP), osteopontin (OP) and calcium deposits. H&E stain was used to assess pre-osteoblasts within the dermal template. RESULTS: NapASCs spheres were visible in 1-2 weeks and their stemness confirmed in vitro by clonal expansion. Adhesion of napASCs to Integra® and phenotype change to fibroblast-like precursors was achieved in 48-72 hours. Phenotype change to the osteogenic lineage was obtained in 3-7 days, strong ALP activity in 14 days, OP positivity and calcium deposits on Von Kossa in 21 days. Spheres of napASCs and pre-osteoblasts were visible on H&E stain in histology sections within Integra® fibers. CONCLUSIONS: NapASCs can grow and differentiate in pre-osteoblasts within a clinically available three-dimensional regenerative template such as Integra®. These promising results should encourage furtherin vivo studies for future clinical application.