Novel Cell-Loading Ceramic Scaffolds for Promoting Vascularized Mandibular Bone Regeneration

Objectives: Bone tissue engineering based on cell-loading scaffolds has emerged as a promising application for treatments of large mandibular bone defect. It is still a major obstacle to maintain the long-term survival of seeded cells which participate in tissue regeneration. Hence, we fabricate a novel cell-loading ceramic scaffold (CLC) to improve the survival of seeded cells and accelerate the vascularized mandibular bone healing.
Methods: Adipose-derived stem cells (ADSCs) were utilized as seeded cells and pretreated by FG-4592, which could activate the expression of HIF-1α. The CLC scaffold was fabricated by a 3D printing technique based on a pre-gel environment. During the preparation, FG-4592 treated ADSCs could be induced to the surface of scaffold directly. The morphology of CLC was detected by a scanning electron microscope (SEM) and the immunofluorescence staining assay. The survival and proliferation of ADSCs on scaffolds were evaluated by flow cytometry and CCK-8 assay. The in vitro angiogenesis and osteogenesis of scaffolds were evaluated by quantitative PCR (qPCR), western blot, alkaline phosphatase staining (ALP) and tube formation tests.
Results: Our results indicated that 50 μM was an appropriate and effective concentration of FG-4592 to enhance HIF-1α expression of ADSCs. After printing, ADSCs were successfully loaded on the surface of CLC scaffolds and spread well. In addition, ADSCs on CLC exhibited higher viability for a long time. The expression of osteogenic-related genes was significantly up-regulated in ADSCs on CLC. Meanwhile, the secretion of ADSCs on CLC could enhance the ALP activity of bone marrow mesenchymal stem cells (BMSCs) and tube formation of human umbilical vein endothelial cells (HUVECs).
Conclusions: The CLC scaffold holds promise for maintaining the long-term survival of ADSCs, and FG-4592 treated ADSCs can modulate coupling of angiogenesis and osteogenesis. Our novel scaffold is a promising biomaterial for mandibular bone repair.