Enhancement of osteogenic differentiation of human adipose derived stem cells by the controlled release of platelet lysates from hybrid scaffolds produced by supercritical fluid foaming

A new generation of scaffolds capable of acting not only as support for cells but also as a source of biological
cues to promote tissue regeneration is currently a hot topic of in bone Tissue Engineering (TE) research. The
inclusion of growth factor (GF) controlled release functionalities in the scaffolds is a possible strategy to
achieve such goal. Platelet Lysate (PL) is an autologous source of GFs, providing several bioactive agents
known to act on bone regeneration. In this study, chitosan-chondroitin sulfate nanoparticles loaded with
PL were included in a poly(D,L-lactic acid) foam produced by supercritical fluid foaming. The tridimensional
(3D) structures were then seeded with human adipose-derived stem cells (hASCs) and cultured in vitro
under osteogenic stimulus. The osteogenic differentiation of the seeded hASCs was observed earlier for the
PL-loaded constructs, as shown by the earlier alkaline phosphatase peak and calcium detection and stronger
Runx2 expression at day 7 of culture, in comparison with the control scaffolds. Osteocalcin gene expression
was upregulated in presence of PL during all culture period, which indicates an enhanced osteogenic induction.
These results suggest the synergistic effect of PL and hASCs in combinatory TE strategies and support the
potential of PL to increase the multifunctionality of the 3D hybrid construct for bone TE applications.