Angiogenesis in newly regenerated bone by secretomes of human mesenchymal stem cells / 대한악안면성형재건외과학회지

BACKGROUND: For an effective bone graft for reconstruction of the maxillofacial region, an adequate vascular network will be required to supply blood, osteoprogenitor cells, and growth factors. We previously reported that the secretomes of bone marrow-derived mesenchymal stem cells (MSC-CM) contain numerous growth factors such as insulin-like growth factor (IGF)-1, transforming growth factor (TGF)-β1, and vascular endothelial growth factor (VEGF), which can affect the cellular characteristics and behavior of regenerating bone cells. We hypothesized that angiogenesis is an important step for bone regeneration, and VEGF is one of the crucial factors in MSC-CM that would enhance its osteogenic potential. In the present study, we focused on VEGF in MSC-CM and evaluated the angiogenic and osteogenic potentials of MSC-CM for bone regeneration. METHODS: Cytokines in MSC-CM were measured by enzyme-linked immunosorbent assay (ELISA). Human umbilical vein endothelial cells (HUVECs) were cultured with MSC-CM or MSC-CM with anti-VEGF antibody (MSC-CM + anti-VEGF) for neutralization, and tube formation was evaluated. For the evaluation of bone and blood vessel formation with micro-computed tomography (micro-CT) and for the histological and immunohistochemical analyses, a rat calvarial bone defect model was used. RESULTS: The concentrations of IGF-1, VEGF, and TGF-β1 in MSC-CM were 1515.6 ± 211.8 pg/mL, 465.8 ± 108.8 pg/mL, and 339.8 ± 14.4 pg/mL, respectively. Tube formation of HUVECs, bone formation, and blood vessel formation were increased in the MSC-CM group but decreased in the MSC-CM + anti-VEGF group. Histological findings suggested that new bone formation in the entire defect was observed in the MSC-CM group although it was decreased in the MSC-CM + anti-VEGF group. Immunohistochemistry indicated that angiogenesis and migration of endogenous stem cells were much more abundant in the MSC-CM group than in the MSC-CM + anti-VEGF group. CONCLUSIONS: VEGF is considered a crucial factor in MSC-CM, and MSC-CM is proposed to be an adequate therapeutic agent for bone regeneration with angiogenesis.

Regulation of the Wnt Signaling Pathways during Cell Culture of Human Mesenchymal Stem Cells for Efficient Bone Regeneration / Oral Science International

Tissue engineering and bone regeneration techniques using mesenchymal stem cells (MSCs) have started to be applied to the field of oral and maxillofacial surgery. Clinically, a shortened treatment time and improved efficiency are necessary because of the patients' needs and the running cost of cell culture. In the present study, the cultivation process for human MSCs (hMSCs) was examined by regulating the Wnt signaling pathway. We activated Wnt signaling with LiCl and inhibited Wnt signaling with sFRP-3 (secreted Frizzled-Related Protein-3). The proliferation of LiCl-treated hMSCs was examined by studying the cell growth rate and performing BrdU assays. Osteogenic differentiation of sFRP-3-treated hMSCs was examined by alizarin red staining, and osteogenic gene expression on days 7 and 14 after induction was examined by reverse-transcription polymerase chain reaction (RT-PCR) analysis and quantitative real-time RT-PCR analysis. LiCl-treated hMSCs showed increased cell numbers and BrdU-positive cells as compared to the untreated cells. Alizarin red staining showed early mineralization of hMSCs on day 7 of the sFRP-3 treatment. A high expression level of the alkaline phosphatase gene on days 7 and 14 of sFRP-3 treatment was also demonstrated. These results suggest that the regulation of the Wnt signaling pathway contributes to the increased cell numbers and the early osteogenic differentiation of hMSCs. This study supports the possibility that the regulation of the Wnt signaling pathway contributes to the development of effective and efficient bone regeneration techniques.