Effects of TGF-β1 and alginate on the differentiation of rabbit bone marrow-derived mesenchymal stem cells into a chondrocyte cell lineage

Alginate and its application to tissue engineering

Alginate is a polysaccharide of natural origin, which shows outstanding properties of biocompatibility, gel forming ability, non-toxicity, biodegradability and easy to process. Due to these excellent properties of alginate, sodium alginate, a hydrogel form of alginate, oxidized alginate and other alginate based materials are used in various biomedical fields, especially in drug delivery, wound healing and tissue engineering. Alginate can be easily processed as the 3D scaffolding materials which includes hydrogels, microcapsules, microspheres, foams, sponges, and fibers and these alginate based bio-polymeric materials have particularly used in tissue healing, healing of bone injuries, scars, wound, cartilage repair and treatment, new bone regeneration, scaffolds for the cell growth. Alginate can be easily modified and blended by adopting some physical and chemical processes and the new alginate derivative materials obtained have new different structures, functions, and properties having improved mechanical strength, cell affinity and property of gelation. This can be attained due to combination with other different biomaterials, chemical and physical crosslinking, and immobilization of definite ligands (sugar and peptide molecules). Hence alginate, its modified forms, derivative and composite materials are found to be more attractive towards tissue engineering. This article provides a comprehensive outline of properties, structural aspects, and application in tissue engineering.

The effect of cartilage extracellular matrix particle size on the chondrogenic differentiation of bone marrow mesenchymal stem cells

Aim: To investigate the effect of cartilage extracellular matrix (ECM) particle size on the chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Materials & methods: BMSCs were seeded into the scaffolds fabricated by small particle ECM materials and large particle ECM materials. For the positive control, chondrogenically induced BMSCs were seeded into commercial poly-lactic-glycolic acid scaffolds. Macroscopic observation, histological and immunohistochemical staining, mechanical testing and biochemical analysis were performed to the cell-scaffold constructs. Results: BMSCs in small particle ECM materials and poly-lactic-glycolic acid scaffolds were induced to differentiate into chondrocytes, while BMSCs in the large particle ECM materials scaffold did not differentiate into chondrocytes. Conclusion: The small ECM particle materials improved the induction ability of the cartilage ECM-derived scaffold.

Leptin attenuates the growth of rabbit mesenchymal stem cells via the extracellular signal-regulated kinase signaling pathway

When stimulated, mesenchymal stem cells (MSCs) may differentiate into chondroblasts, adipocytes or osteoblasts. Leptin is an adipocyte-derived hormone, which regulates food intake and glucose homeostasis. The aim of the present study was to identify the potential role of mitogen-activated protein kinase in the leptin-induced growth of rabbit bone MSCs (rBMSCs). Various concentrations of leptin were used to culture rBMSCs and the viability of cells was observed as well as alterations in the phosphorylation state of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase and p38. It was revealed that the growth of leptin-treated rBMSCs was primarily inhibited by phosphorylated ERK1/2, which was mediated by the leptin receptor. In conclusion, the results of the present study demonstrated that leptin inhibits the growth of rBMSCs principally via the ERK1/2 signaling pathway.

The effects of doxorubicin-loaded liposomes on viability, stem cell surface marker expression and secretion of vascular endothelial growth factor of three-dimensional stem cell spheroids

The aim of the present study was to evaluate the effects of anionic, cationic and neutral liposomes containing doxorubicin on the cellular viability and osteogenic differentiation of three-dimensional stem cell spheroids. Doxorubicin-loaded liposomes were prepared using the traditional thin-lipid-film-hydration method and were characterized using transmission electron microscopy and a zeta potential analyzer. The doxorubicin release profile from these liposomes was also analyzed in vitro. Three-dimensional cell spheroids were fabricated using silicon elastomer-based concave microwells. Qualitative results of cellular viability were observed using a confocal microscope and quantitative cellular viability was evaluated using a Cell-Counting Kit-8 (CCK-8) assay. Furthermore, the secretion of vascular endothelial growth factor was evaluated. Western blot analysis was performed to assess the expression of collagen I and glyceraldehyde 3-phosphate. Results indicated that the spheroids were well formed in silicon elastomer-based concave microwells on day 1. In general, the shapes of the cells in the in the doxorubicin-loaded anionic, cationic and neutral liposome groups were similar to the control group except for the 10 µg/ml groups on days 3, 5, and 7. No significant changes in cellular viability were noted with the addition of doxorubicin at day 1 but significant decreases in cellular viability were noted with application of doxorubicin at day 5. Notably, higher concentrations of doxorubicin reduced the secretion of vascular endothelial growth factor and stem cell marker expression. To conclude, the present study indicated that doxorubicin-loaded anionic liposomes produced the most sustained release profile and cationic liposomes produced the highest uptake of the stem cell spheroids. These findings suggested that higher concentrations of doxorubicin-loaded liposomes affected cellular viability, the secretion of vascular endothelial growth factor and stem cell marker expression.

The role of Sox9 in collagen hydrogel-mediated chondrogenic differentiation of adult mesenchymal stem cells (MSCs)

Sox9 is a transcription factor that regulates chondrogenesis, but its role in the chondrogenic differentiation of mesenchymal stem cells (MSCs) triggered by materials is poorly understood.

Piezoelectric material - A promising approach for bone and cartilage regeneration

Bone and cartilage are major weight-bearing connective tissues in human and possesses utmost vulnerability for degeneration. The potential causes are mechanical trauma, cancer and disease condition like osteoarthritis and osteoporosis, etc. The regeneration/repair is a challenging, since their complex structures and activities. Current treatment options comprise of auto graft, allograft, artificial bone substituent, autologous chondrocyte implantation, mosaicplasty, marrow stimulation and tissue engineering. Were incompetent to overcome the problem like abandoned growth factor degradation, indistinct growth factor dose and lack of integrity and mechanical properties in regenerated tissues. Present, paper focuses on the novel hypothesis for regeneration of bone and cartilage by using piezoelectric smart property of scaffold material.