Changes in osteogenesis by human dental pulp stem cells on porcine decellularised adipose tissue solid foams of different porosity

Abstract

The extracellular matrix of white adipose tissue (AT) is a very promising biomaterial for tissue engineering, due to its abundance, easy accessibility, malleability, and proven biological activity. Decellularised AT (DAT) can be processed by freeze-drying in acetic acid solutions, and changing the DAT concentration in the solution gives rise to three-dimensional (3D) scaffolds of different stiffness and porosity. In a previous report, we demonstrated that human Dental Pulp Stem Cells (hDPSCs) could differentiate to osteoblasts and generate mineralised bone on 3D solid foams of porcine Decellularised Adipose Tissue (pDAT) at a concentration of 0.5 % (w/v). In this research work, we assessed whether and how osteogenesis by hDPSCs would be regulated by testing pDAT solid foams formulated at three different concentrations: 0.25 % (w/v), 0.5 % (w/v), and 1 % (w/v), which showed different stiffness, porosity and water retention properties. As a control condition we tested solid foams formulated with 0.5 % bovine Collagen-I. Thus, we performed Alkaline Phosphatase and Alizarin Red staining, together with Transmission Electron Microscopy and the detection of osteoblastic differentiation markers Osterix and Osteocalcin at both protein and transcript level, to compare the osteogenesis mediated by hDPSCs grown on all these 3D scaffolds, in the presence or absence of osteoblastic induction media. Our results demonstrate that pDAT at 0.25 % supported osteogenesis better than the rest of tested scaffolds, including bovine Collagen-I, in 3D hDPSC cultures. This enhanced osteogenesis could be attributed to the formulation of 0.25 % pDAT solid foams, which presented a higher porosity.

Keywords

• dental pulp stem cells
• 3d culture
• adipose tissue
• osteogenesis
• extracellular matrix
• decellularisation
• solid foam
• cell differentiation
• mineralisation