Effects of exogenous glycosaminoglycans on human chondrocytes cultivated on type II collagen scaffolds.

Cartilage extracellular matrix (ECM) is composed primarily of type II collagen (COL II) and large, networks of proteoglycans (PGs) that contain glycosaminoglycans such as hyaluronic acid (HA) and chondroitin sulfate (CS). Since cartilage shows little tendency for self-repair, injuries are kept unhealed for years and can eventually lead to further degeneration. During the past decades, many investigations have pursued techniques to stimulate articular cartilage repair or regeneration. The current study assessed the effects of exogenous glycosaminoglycans (GAGs) including CS-A, CS-B, CS-C, heparan sulfate and HA, administration on human chondrocytes in terms of proliferation and matrix synthesis, while the cells were seeded and grown on the genipin-crosslinked collagen type II (COL II) scaffold. DNA content was measured by Hoechst dye intercalation, matrix deposition was evaluated by DMMB dye. Expression of collagen II and aggrecan mRNAs was assessed by RT-PCR, followed by gel electrophoresis. In a 28-day in vitro culture, administration of 5 microg/ml CS-A, 50 microg/ml CS-B, 50 microg/ml CS-C, 5 microg/ml HS, and 500 kDa HA led to significant increase in biosynthesis rate of PGs. Gene expression of aggrecan and collagen II were upregulated by CS-A, CS-C and HA. These results showed considerable relevance of GAGs to the issue of in vitro/ex vivo neo-cartilage synthesis for tissue engineering and regenerative medical applications.

Stem Cells from Human Exfoliated Deciduous Teeth: A Concise Review.

Stem Cells from Human Exfoliated Deciduous Teeth (SHED) originate from the embryonic neural crest as ectodermal mesenchymal stem cells and are isolated from human deciduous teeth. SHED expresses the same cell markers as Embryonic Stem Cells (ESCs), such as OCT4 and NANOG, which make SHED to have a significant impact on clinical applications. SHED possess higher rates of proliferation, higher telomerase activity, increased cell population doubling, form sphere-like clusters, and possess immature and multi-differentiation capacity; such high plasticity makes SHED one of the most popular sources of stem cells for biomedical engineering. In this review, we describe the isolation and banking method, the current development of SHED in regenerative medicine and tissue engineering in vitro and in vivo.

A study of the differentiation of stem cells from human exfoliated deciduous teeth on 3D silk fibroin scaffolds using static and dynamic culture paradigms.

Stem cells from human exfoliated deciduous teeth (SHED) are considered the best current source of human stem cells due to their ability to differentiate into multiple cell lineages. Dynamic co-culture systems can improve the culture environment, as they provide cells with signaling factors, extracellular matrixes, and cellular shear force, as well as enable the formation of heterotypic clusters. We seeded SHED in 3D silk fibroin porous scaffolds under static and dynamic cultures for 28 days, using the NIH3T3 cultivated medium as an induction agent. Many hepatospheres formed in these porous scaffolds, and cellular viability was shown to continually increase by MTT assays. Hepatic AFP and ALB gene expression, as well as glycogen storage, albumin secretion, and urea synthesis, were greater in cells in the 3D porous scaffold under a dynamic culture than in those cultured under 3D static culture and petri dish conditions. However, the 3D static culture is still superior to the traditional petri dish culture. The NIH3T3 cultivated medium can significantly induce hepatic differentiation of SHED, while the 3D dynamic culture system significantly enhances hepatic differentiation of SHED. This study provides alternative sources of hepatocytes for liver disease treatment.

Effect of chitosan conduit under a dynamic culture on the proliferation and neural differentiation of human exfoliated deciduous teeth stem cells.

Ex vivo engineering of artificial nerve conduit is a suitable alternative clinical treatment for nerve injuries. Stem cells from human exfoliated deciduous teeth (SHEDs) have been considered as alternative sources of adult stem cells because of their potential to differentiate into multiple cell lineages. These cells, when cultured in six-well plates, exhibited a spindle fibroblastic morphology, whereas those under a dynamic culture aggregated into neurosphere-like clusters in the chitosan conduit. In this study, we confirmed that SHEDs efficiently express the neural stem cell marker nestin, the early neural cell marker ß-III-tubulin, the late neural marker neuron-specific enolase and the glial cell markers glial fibrillary acidic protein (GFAP) and 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase). The three-dimensional chitosan conduit and dynamic culture system generated fluid shear stress and enhanced nutrient transfer, promoting the differentiation of SHEDs to neural cells. In particular, the gene expressions of GFAP and CNPase increased by 28- and 53-fold, respectively. This study provides evidence for the dynamic culture of SHEDs during ex vivo neural differentiation and demonstrates its potential for cell therapy in neurological diseases. Copyright © 2013 John Wiley & Sons, Ltd.

Osteogenic differentiation and mineralization of human exfoliated deciduous teeth stem cells on modified chitosan scaffold.

Stem cells from human exfoliated deciduous teeth (SHEDs) have been considered as alternative sources of adult stem cells in tissue engineering because of their potential to differentiate into multiple cell lineages. Strontium has an important function in bone remodeling because it can simulate bone formation and decrease bone resorption. In this study, the effects of strontium phosphate on the osteogenic differentiation of SHEDs were investigated. Strontium phosphate was found to enhance the osteogenic differentiation of SHEDs with up-regulated osteoblast-related gene expression. The proliferation of SHEDs was slightly inhibited by chitosan scaffolds; however, type-I collagen expression, alkaline phosphatase activity, and calcium deposition on chitosan scaffolds containing strontium were significantly enhanced. Furthermore, cells seeded in a 3D scaffold under dynamic culture at an optimal fluid rate might enhance cellular differentiation than static culture in osteoblastic gene expression. This experiment might provide a useful cell resource and dynamic 3D culture for tissue engineering and bone repair.

Type II collagen-chondroitin sulfate-hyaluronan scaffold cross-linked by genipin for cartilage tissue engineering.

Owing to of the limited repair capacity of articular cartilage, it is essential to develop tissue-engineered cartilage for patients suffering from joint disease. Chondroitin sulfate (CS) and hyaluronan (HA) are the components of the cartilage extracellular matrix (ECM) and are known to influence the proliferation and differentiation of chondrocytes. Scaffolds composed of type-II collagen, CS, and HA may create an environment that can preserve the normal phenotype of cells to promote regeneration of cartilage-like constructs. In this investigation, we prepared and characterized 3-dimensional type-II collagen scaffolds both with and without HA and CS. Porous composite scaffolds fabricated by freeze-drying showed interconnected pores with mean diameters of 140+/-30 microm and porosities of 92-95% after cross-linking with genipin. After a 14-day in vitro culture, morphologically round chondrocytes were found to be uniformly distributed throughout the sponges. Expression of genes of aggrecan, type-II collagen and cartilage oligomeric matrix protein (COMP) was statistically and significantly increased on scaffolds with CS and HA than those without CS and HA. Furthermore, there was a markedly greater accumulation of proteoglycans (PGs) on the scaffolds with CS and HA.