Osteogenic differentiation ability of human mesenchymal stem cells on Chitosan/Poly (Caprolactone)/nano beta Tricalcium Phosphate composite scaffolds.

Our work depicts the development and characterization of Chitosan/Poly (caprolactone)/nano beta-Tricalcium phosphate (CS/PCL/ß-TCP) porous composite scaffolds by freeze drying method. Addition of PCL to CS/ß-TCP composite scaffolds had significantly increased the compressive strength besides decelerating the degradation rate. Human mesenchymal stem cells (hMSCs) were chosen to assess in-vitro biocompatibility of the prepared scaffolds in terms of cell viability, cell attachment and proliferation by MTT assay, SEM and DNA Quantification assays respectively. Further, increased osteogenic differentiation assay results (Alkaline Phosphatase assay and Total calcium content) revealed the role of ß-TCP in composite scaffolds. Altogether, results suggest the potentiality of prepared porous freeze dried composite scaffolds in bone tissue engineering applications.

Design and Assessment of a Dynamic Perfusion Bioreactor for Large Bone Tissue Engineering Scaffolds.

Bioreactors can be used to apply fluid flow in vitro to scaffolds to improve mass transport of media and apply mechanical forces to cells. In this study, we developed and tested an autoclavable, modular perfusion bioreactor suitable for large scaffolds. We investigated the effects of fluid flow induced shear stress (FFSS) on osteogenic differentiation of human embryonic stem cell-derived mesenchymal progenitors (hES-MP cells) cultured on large polyurethane (PU) scaffolds (30 mm diameter × 5 mm thickness) in osteogenesis induction media (OIM). After seeding, scaffolds were either maintained in static conditions or transferred to the bioreactor 3 days post-seeding and a continuous flow rate of 3.47 mL/min was applied. Alkaline phosphatase activity (ALP) was used to evaluate osteogenic differentiation and resazurin salt reduction (RR) to measure metabolic activity after 10 days. Cultures subjected to flow contained significantly more metabolically active cells and higher total DNA content, as well as significantly higher ALP activity compared to scaffolds grown in static culture. These results confirm the responsiveness of hES-MP cells to fluid flow stimuli, and present a cost-effective, user-friendly bioreactor capable of supporting the growth and differentiation of mesenchymal progenitor cells within scaffolds capable of filling large bone defects.

Role of signaling pathways in mesenchymal stem cell differentiation.

Mesenchymal Stem Cells (MSCs) are self-renewing cells with ability to differentiate into organized, functional network of cells. In recent past research in developing clinical applications for MSCs has increased significantly. MSCs exhibit multi potential proliferation, and are capable of differentiating into cartilage, bone, neuronal cells and adipocytes, etc. Signaling pathways, transcription factors and growth factors modulate the differentiation of MSCs into different cell lineages. Besides, physical factors may regulate the molecular differentiation of stem cells. The main theme of this paper is to review the signaling pathways related to bone morphogenetic proteins (BMPs), epidermal growth factors (EGF), transforming growth factors (TGF), wingless type MMTV integration site (wnt) proteins, fibroblastic growth factor (FGF), and transcriptional regulating factors significance in the MSCs differentiation.

Optimization of amorphadiene production in engineered yeast by response surface methodology.

Isoprenoids are among the most diverse bioactive compounds synthesized by biological systems. The superiority of these compounds has expanded their utility from pharmaceutical to fragrances, including biofuel industries. In the present study, an engineered yeast strain Saccharomyces cerevisiae (YCF-AD1) was optimized for production of Amorpha-4, 11-diene, a precursor of anti-malarial drug using response surface methodology. The effect of four critical parameters such as KH2PO4, methionine, pH and temperature were evaluated both qualitatively and quantitatively and further optimized for enhanced amorphadiene production by using a central composite design and model validation. The "goodness of fit" of the regression equation and model fit (R2) of 0.9896 demonstrate this study to be an effective model. Further, this model will be used to validate theoretically and experimentally at the higher level of amorphadiene production with the combination of the optimized values of KH2PO4 (4.0), methionine (1.49), pH (5.4) and temperature (33 °C).

Enhanced proliferation and osteogenic differentiation of human umbilical cord blood stem cells by L-ascorbic acid, in vitro.

The multilineage potentiality of cord blood stem cells has been experimentally proven in a number of cell based therapies. Umbilical cord blood (UCB) derived mesenchymal stem cells (MSCs), on prolonged exposure with Lascorbic acid have been successfully differentiated in to osteoblasts (bone forming cells) without altering the phenotype of the cells. In this case study, the role of L-ascorbic acid on collagen biosynthesis and mineral deposition in MSCs has been assessed, which are ultimately matured in to an insoluble extra cellular matrix (ECM), giving mechanical strength to the bone cells. Moreover, up to specific concentration of L-ascorbic acid (250µM), proliferation as well as differentiation potential of the cells remains unaltered. Further increase in concentrations of L-ascorbic acid (500 µM) reduced the cell proliferation and subsequently leads to morphological changes in the cultures. This may be due to an immature antioxidant defense system, which can be overcome by treating the cell cultures with antioxidants. Our final results conclude that Lascorbic acid has positive effect on the ostogenic differentiation of cord blood stem cells, and the concentration of ascorbic acid is vital in cell proliferation and differentiation.