Papers by Keyword: Osteogenic Differentiation

Abstract: The aim of this work was to identify robust and reproducible signatures characterizing the different steps of bone cell differentiation, from precursors to mature bone cells, using approaches allowing characterization by label-free imaging. Human mesenchymal stromal cells (hMSCs) were cultured either in a growth medium (GM), unable to induce cell differentiation by itself, or in an osteogenic differentiation medium (ODM) on hydroxyapatite ceramics or borosilicate glass. Cell density as well as cell structure, size, and morphology were investigated. A fluorescence microscopy-based approach was followed, using fluorescent labelling of cell features. Some early morphological changes of hMSC during osteogenic differentiation were identified as soon as 48h that were accentuated after 7 days of culture. Cell density was higher when cells were cultured in GM and the cells exhibited significantly smaller nuclei (size ratio about 1.3-1.5) than those cultured in ODM, regardless of the culture support. In ODM, the cells were also of bigger size (1.2 to 1.5 times) and their focal adhesions were reinforcedType I collagen, a gold standard marker of osteogenic differentiation, appeared more intense in ODM. These cell features can be determined using multimodal label-free imaging methods to characterize the differentiation state of hMSCs at the biomaterial surface. They give rise to new cost-effective approaches to investigate cell behavior by suppressing the chemical markers and reducing both the number of needed samples and the requested time to do so.

Abstract: Vascular endothelial growth factor (VEGF) and bone morphogenetic proteins (BMP-7) are key regulators of angiogenesis and osteogenesis during bone regeneration. The aim of this study was to investigate the possibility of realizing sequential release of the two growth factors using a novel composite scaffold. Poly(lactic-co-glycolic acid) (PLGA)-Akermanite (AK) microspheres were used to make the composite scaffold, which was then loaded with BMP-7, followed by embedding in a gelatin hydrogel matrix loaded with VEGF. The release profiles of the growth factors were studied and selected osteogenic related markers of bone marrow stromal cells (BMSCs) were analysed. It was shown that the composite scaffolds exhibited a fast initial burst release of VEGF within the first 3 days and a sustained slow release of BMP-7 over the full period of 20 days. The in vitro proliferation and differentiation of the BMSCs cultured in the osteogenic medium were enhanced by 1 to 2 times, resulting from the additionally and sequentially release of growth factors from the PLGA-AK/gelatin composite scaffolds.

Abstract: Osteoblasts were perceived as pivotal cells, recognized as the cells that control both the formative and the resorptive phases of the bone remodeling cycle. Osteoblasts were an essential requirement for osteoclastogenesis though expressing or secreating bioactive osteoclast-differentiation-regulatory proteins, osteoclast differentiation factor (ODF)was the most important factor among these, ODF participate nearly in every step of differentiation and activation of osteoclasts. In addition, intercellular adhesion molecule-1 (ICAM-1)and its receptors LFA-1 play a role in osteoclast development by affecting adhesion between stromal cells and osteoclast progenitors before the occurrence of ODF-ODF receptor signaling. However, it is not clear about the relationship between ODF, ICAM-1 expression of osteoblasts and differentiation state of osteoblasts. So,the aim of this study was to investgate whether the expression of ODF, ICAM-1 depended on the stage of osteoblastic differentiation from rat bone marrow mesenchymal stem cells(rBMSCs). The viability of rBMSCs is reduced significantly by osteogenic inducement as differentiating into osteoblasts, ALPase activity of OS-treated rBMSCs was enhanced obviously within 9 days , declined subsequently and recovered nearly the original level at day 14. Expression of ODF is enhanced with osteogenic differentiation guadully. whereas, expression of ICAM-1 is activated at OS-treated day 6, then keeping at a stable level. This study indicated that rBMSCs undergoing osteogenic inducement was an ideal model for studying the differentiation and maturation of osteoblasts. During the early stage of differentiation along osteoblasts from stem cells to osteocytes, rBMSCs or Osteoprogenitor react somewhat differently from osteoblasts, suggesting the ability of osteoblasts to regulating differentiation and maturation of osteoclasts have been improved with osteogenic culture.

Abstract: Mesenchymal stem cells(MSCs) have the potential to self-replicate, proliferate and differentiate into chondrocytes, adipocytes, osteocytes and myocytes. Recent studies indicate that vitamin K2 plays a role in bone metabolism. But the mechanism is still unclear. We evaluated effect of vitamin K2 on osteogenesis and adipogenesis of MSCs from umbilical cord blood(UCB). By exposing MSCs to osteogenic and adipogenic medium with and without vitamin K2, the effects of vitamin K2 were analyzed. The results showed that vitamin K2 inhibits adipogenesis while at the same time it stimulates osteoblastic differentiation. These data are expected to provide novel information needed for successful therapeutic development for various types of osteoporosis and similar diseases related to bone formation.

Abstract: This study was to determine the ectopic osteogenic ability of BMSCs in combination with a scaffolding material comprising hydroxyapatite and β-tricalcium phosphate matrix (HA/β-TCP). BMSCs were obtained from the SD rats and induced to osteogenesis. Then these induced cells were seeded into HA/β-TCP and the constructs were auto-implanted subcutaneously for up to 12 weeks. Histological analysis, immunostaing, RT-PCR and transmission electron microscopy of the retrieved specimens at various intervals showed obvious trends of ectopic bone formation with obvious alteration of cellular phenotype.

Abstract: Previous study showed that the novel poly(ε-caprolactone)–organosiloxane nano-hybrid material (SiOPCL) had bioactivity, biodegradability, and mechanical properties comparable to those of human cancellous bone. In this study, hydroxyl carbonate apatite layer (HCA) was preformed on the surface of SiOPCL, which mimicked the events likely to occur in vivo, and cellular behaviors of human bone marrow stromal cells (hBMSCs) were investigated during the osteogenic differentiation on its surface (SiOPCL/HCA). Initial attachment, proliferation, and ALP activities of hBMSCs were comparable to those on tissue culture plates (TCPs), while the calcium content in the cell layer showed significantly higher value. It means that this novel bioactive nano-hybrid material is likely to be a promising candidate for bone grafting materials because of good hBMSCs responses as well as apatite forming ability in the simulated body fluid.

Abstract: Fibrin is a natural polymer with excellent biocompatibility and widely used as a cell delivery vehicle in tissue engineering. However, fibrin of low concentration is not able to promote cell growth and differentiation within a desired time because of contraction and biodegradation of cell-seeded matrices. In this study we investigated effects of combining fibrin with collagen on growth and osteogenic differentiation of bone marrow stromal cells (BMSCs). Rabbit BMSCs-populated fibrin hydrogels with or without collagen were fabricated and cultured by the free floating method for 4 weeks. The DNA content of fibrin/collagen matrix significantly increased the growth of BMSCs compared to the fibrin-only matrix at 2week. Alkaline phosphatase activity was significantly higher in the fibrin/collagen matrix (71.0 nmol of p-nitrophenol /min/disc) than the fibrin-only matrix (45.1 nmol of p-nitrophenol /min/disc). Deposition of calcium was not significantly different between two groups. Histological examination also revealed more matured organization and deposition of collagen fibers and more concentric calcium deposition in the fibrin/collagen matrix compared to the fibrin-only matrix. These results indicated that fibrin/collagen matrix could be more effective than fibrin alone in supporting growth and osteogenic differentiation of BMSCs.