Effects of electromagnetic stimulation on gene expression of mesenchymal stem cells and repair of bone lesions

Objective: Most people experience bone damage and bone disorders during their lifetimes. The use of autografts is a suitable way for injury recovery and healing. Mesenchymal stem cells [MSCs] are key players in tissue engineering and regenerative medicine. Their proliferation potential and multipotent differentiation ability enable MSCs to be considered as appropriate cells for therapy and clinical applications. Differentiation of stem cells depends on their microenvironment and biophysical stimulations. The aim of this study is to analyze the effects of an electromagnetic field on osteogenic differentiation of stem cells

Materials and Methods: In this experimental animal study, we assessed the effects of the essential parameters of a pulsatile electromagnetic field on osteogenic differentiation. The main purpose was to identify an optimum electromagnetic field for osteogenesis induction. After isolating MSCs from male Wistar rats, passage-3 [P3] cells were exposed to an electromagnetic field that had an intensity of 0.2 millitesla [mT] and frequency of 15 Hz for 10 days. Flow cytometry analysis confirmed the mesenchymal identity of the isolated cells. Pulsatile electromagnetic field-stimulated cells were examined by immunocytochemistry and real-time polymerase chain reaction [PCR]

Results: Electromagnetic field stimulation alone motivated the expression of osteogenic genes. This stimulation was more effective when combined with osteogenic differentiation medium 6 hours per day for 10 days. For the in vivo study, an incision was made in the cranium of each animal, after which we implanted a collagen scaffold seeded with stimulated cells into the animals. Histological analysis revealed bone formation after 10 weeks of implantation

Conclusion: We have shown that the combined use of chemical factors and an electromagnetic field was more effective for inducing osteogenesis. These elements have synergistic effects and are beneficial for bone tissue engineering applications

In vivo vascularization of endothelial cells derived from bone marrow mesenchymal stem cells in SCID mouse model

Objective: In vivo and in vitro stem cell differentiation into endothelial cells is a promising area of research for tissue engineering and cell therapy

Materials and Methods: We induced human mesenchymal stem cells [MSCs] to differentiate to endothelial cells that had the ability to form capillaries on an extracellular matrix [ECM] gel. Thereafter, the differentiated endothelial cells at early stage were characterized by expression of specific markers such as von Willebrand factor [vWF], vascular endothelial growth factor [VEGF] receptor 2, and CD31. In this experimental model, the endothelial cells were transplanted into the groins of severe combined immunodeficiency [SCID] mice. After 30 days, we obtained tissue biopsies from the transplantation sites. Biopsies were processed for histopathological and double immunohistochemistry [DIHC] staining

Results: Endothelial cells at the early stage of differentiation expressed endothelial markers. Hematoxylin and eosin [H and E] staining, in addition to DIHC demonstrated homing of the endothelial cells that underwent vascularization in the injected site

Conclusion: The data clearly showed that endothelial cells at the early stage of differentiation underwent neovascularization in vivo in SCID mice. Endothelial cells at their early stage of differentiation have been proven to be efficient for treatment of diseases with impaired vasculogenesis

Capillary network formation by endothelial cells differentiated from human bone marrow mesenchymal stem cells

Human bone marrow derived mesenchymal stem cells [HBMSCs] have the potential to differentiate into cells such as adipocyte, osteocyte, hepatocyte and endothelial cells. In this study, the differentiation of hBMSCs into endothelial like-cells was induced in presence of vascular endothelial growth factor [VEGF] and insulin-like growth factor [IGF-1]. The differentiated endothelial cells were examined for their ability to express VEGF receptor-2 [VEGFR2] and von willebrand factor [vWF]. Then the cells were adopted to grow and develop capillary network in a semisolid gel matrix in vitro. The capillary network formation in a well of 24-well plate was found to be 85% in presence of VEGF [50ng/ml] and IGF-1 [20ng/ml] of the culture media. These data may suggest that the expression of endothelial markers in endothelial like-cells derived from hBMSCs is associated with their ability to form capillaries

Development of a novel three-dimensional biocompatible nanofibrous scaffold for the expansion and hepatogenic differentiation of human bone marrow mesenchymal stem cells

In this present study, we examined the differentiation potential of human bone marrow derived mesenchymal stem cells [hBMSCs] into hepatocytes on a three-dimentional [3D] nanofibrous scaffold formed by Poly [e-caprolactone] [PCL], collagen and polyethersulfone [PES]. The nanofiber was prepared by the electrospining technique. HBMSCs were isolated using combining gradient density centrifugation with plastic adherence. Flow cytometric analysis was used to identify the isolated MSCs. The performance of the cells on the scaffold was evaluated by scanning electron microscopy [SEM] and MTT assay. The hBMSCs were then cultured in a hepatic differentiation medium containing hepatocyte growth factor [HGF], oncostatin M [OSM] and dexamethasone [DEX] for up to 21 days. The results showed that the isolated hBMSCs expressed specific markers such as CD44, CD166, CD105 and CD13. The integrity of the MSCs was further confirmed by their differentiation potential to osteogenic and adipogenic lineages. Scanning electron micrographs and MTT analysis revealed that the cells adhered and proliferated well on the nanofibrous hybrid scaffolds. Immunocytochemical analysis of albumin and a-fetoprotein [AFP] showed the accumulation of these markers in the differentiated cells on the scaffold. Hepatocyte differentiation was further confirmed by showing expression of albumin, AFP and cytokeratin-19 [CK-19] at mRNA levels in differentiated cells. In conclusion, the evidences presented in this study show that the engineered scaffold is promising for maintenance of hepatocyte-like cells suitable for transplantation