Evaluation of bone regeneration potential of injectable extracellular matrix (ECM) from porcine dermis loaded with biphasic calcium phosphate (BCP) powder.

Extracellular matrix (ECM) contains a wide array of complex proteins, growth factors and cytokines that regulate cell behavior and tissue development. ECM harvested from non-homologous ECM sources still provide a structural support and biochemical cues to cells for effective tissue remodeling. The aim of this study is to evaluate the effect of non-tissue specific decellularized ECM from porcine dermis loaded with biphasic calcium phosphate powder (BCP) in bone regeneration. Thermosensitive ECM hydrogels with BCP powder exhibited a porous morphology with a suitable injectability and increased mechanical stability. In-vitro studies using MC3T3-E1 pre osteoblast cells showed that the injectable ECM hydrogels were biocompatible and supported the osteogenic differentiation. The bone regeneration capacity of the injectable ECM hydrogels was evaluated in-vivo by implanting in rat femoral head for 4 and 8 weeks. Micro-CT and histological staining results indicated that the injectable ECM hydrogels loaded with BCP powder showed higher and improved bone formation compared with the unfilled defect. Injectable ECM loaded with BCP powder is a good potential biomaterial for non-load bearing bone regeneration application.

Enhanced decellularization technique of porcine dermal ECM for tissue engineering applications.

Effective removal of cellular components while retaining extracellular matrix (ECM) proteins is the ultimate goal of decellularization. The aim of this study is to produce a decellularized ECM with highly preserved ECM proteins and to determine the effect of isopropanol as a decellularization solvent on the characteristics of the decellularized porcine skin. Two different protocols were used for porcine skin decellularization. Protocol 1 consisted of Triton-X and sodium dodecyl sulfate (SDS) in water while protocol 2 consisted of Triton-X and SDS in 70% isopropanol. After decellularization, DNA components decreased significantly in protocol 2 with lower amount of lipid content and higher ECM proteins such as collagen (92.91 ±â€¯9.02 µg/mg sample), α-elastin (142.32 ±â€¯6.74 µg/mg sample) and sulfated glycosaminoglycan (sGAG; 7.44 ±â€¯1.30 µg/mg sample) compared with protocol 1 ECM. Higher amount of vascular endothelial growth factor (VEGF; 11.26 ±â€¯0.44 pg/mg sample) content was quantified in protocol 2 compared with protocol 1 while higher trace amount of bone morphogenic protein 2 (BMP-2; 0.28 ±â€¯0.04 pg/mg sample) was also observed in protocol 2 compared with protocol 1. Protocol 2 ECM did not significantly affect the cell viability and exhibited no cytotoxicity when exposed to three different cell lines: L929 fibroblast cells, MC3T3-E1 pre-osteoblast cells, and rat mesenchymal stem cells (BMSC). Subcutaneous implantation after 7 and 21 days revealed higher cell infiltration in protocol 2 ECM and enhanced neovascularization. Isopropanol/surfactants proved to be effective in cell and lipid removal during decellularization while preserving the higher amount of ECM proteins.