Papers by Keyword: Stem Cell

Abstract: Osteoporosis (OP) is a systemic metabolic disease identified with decrease of bone mineral density and deterioration of microstructure leading to fragility fractures in elderly. Boron (B) is assumed to stimulate osteoblasts. Hydroxyapatite (HAp) is clinically used to conduct bone regeneration and improves implant integration. Nano(n)-HAp expands the surface area for cell adhesion and may improve bone regeneration and tissue integration. The objective of this study was to examine the adhesion, proliferation and differentiation of B-n-HAp with mesenchymal stem cells (MSC’s). Human bone marrow derived MSC’s phenotype was assessed using scanning and transmission electron microscopy after combining with B-n-HAp and n-HAp. Cell adhesion and proliferation potential of these ceramics was examined with the real time cell analysis (xCELLigence, Roche Applied Science and ACEA Bioscience, USA) system and adipogenic-osteogenic differentiation was analyzed with morphological and quantitative methods. MSC’s adhesion and proliferation rates (cell index, 4.50) were higher than controls (cell index, 4.00). Adipogenic and osteogenic differentiation potential of MSC’s remained unchanged in the presence of B-n-HAp ceramics. In conclusion, B-n-HAp stimulates MSC’s adhesion, proliferation and differentiation and has a potential to regenerate bone tissue.

Abstract: Purpose: The adult corneal epithelium is maintained by a population of limbal stem cells (LSCs), transmembrane protein prominin, regarded as stem cell marker was investigated on mouse corneal tissue, to study weather contains CD133-expressing cells and their distribution. Methods: Enucleated mouse eyes were embedded in OCT and cryosections were performed for mmunohistochemical studies using the avidin-biotin-peroxidase complex (ABC) procedure. Meanwhile, dissected mouse corneas were analyzed by westernblot. Results: In the adult mouse, 13A4 immunoreactivity was detected at the apical side of superficial corneal epithelium, including the limbus region, but not by stroma and endothelium. 115 KDa protein was approved in corneal tissue by Westernblot. Conclusions: The stem cell activity does not occur along the limbus but presumably presented by small portion of corneal epithelial cells which may hold a similar properties of stem cells.

Abstract: Chimeric proteins have been used for years for various purposes ranging from biomaterials to candidate drug molecules, and from bench to bulk. Regenerative medicine needs various kinds of proteins for providing essential factors for maintaining starting cells, like induced pluripotent stem cells (iPSC), and renewal, proliferation, targeted differentiation of these cells, and as extracellular matrix for the experimental cells. However, there are several challenges associated with making functional chimeric proteins for effective application as biomaterial in this field. Fc-chimeric protein technology could be an effective solution to overcome many of them. These tailored proteins are recently becoming superior choice of biomaterials in stem cell technology and regenerative medicine due to their specific advantageous biophysical and biochemical properties over other chimeric forms of same proteins. Recent advances in recombinant protein-related science and technology also expedited the popularity of this kind of engineered protein. Over the last decade our lab has been pioneering this field, and we and others have been successfully applied Fc-chimeric proteins to overcome many critical issues in stem cell technologies targeting regenerative medicine and tissue engineering. Fc-chimeric protein-based biomaterials, specifically, E-cad-Fc have been preferentially applied for coating of cell culture plates for establishing xenogeneic-agent free monolayer stem cell culture and their maintenance, enhanced directed differentiation of stem cells to specific lineages, and non-enzymatic on-site one-step purification of target cells. Here the technology, recent discoveries, and future direction related with the E-cad-Fc-chimeric protein in connection with regenerative medicine are described.

Abstract: All over the world a large number of people suffer from tooth diseases like dental caries, tooth abscess, and plaques. Tooth loss or damage, which occurs frequently in our society are generally repaired by applying several conventional methods, such as root-canal treatment, direct pulp capping and dental implants. These methods are quite painful, create damage to the surrounding tooth tissues and also may at times have adverse side-effects. The limitations of the conventional methods can be overcome by applying the concept of tooth tissue engineering. Tooth tissue engineering is the application of biosciences and engineering to regenerate a biofunctional tooth, which can be used to replace the missing tooth or repair the damaged tooth. Tissue engineering involves three key elements - cell, scaffold and growth factors, which interact with each other to regenerate a specific tissue. The success of tissue engineering depends on the proper selection of these three key elements and understanding the interactions among them. To bring us close to the realization of a tissue-engineered tooth, immense progress is going on in understanding how tooth is first developed, and there is a good advancement in tooth regeneration. In this review, “tooth tissue engineering” will be discussed, along with the recent advancements and challenges in bring a biofunctional tooth from laboratory out into clinical use.

Abstract: Electrospinning technique is an efficient processing method to manufacture micro-and nanosized fibrous structures by electrostatic force for different applications. In biomaterial field, electrospinning technique has been successfully utilized to prepare new drug delivery materials and tissue engineering scaffolds. Fiber mats of biodegradable polymers having a diameter in the nanoto submicro-scale can be considered to mimic the nanofibrous structure of native extracellular matrix (ECM). Native extracellular matrix, constituted of proteins and polysaccharides improving cells growth in its nanofibrous porous structure, controls not only the cell phenotype, but the whole structure of the biological tissues. In the present study we investigated the effect of electrospun reconstituted collagen fibers onto metals for oral implants devices manufacturing as far as the osteoblastic differentiation potential of stem cells and cytofunctionality of osteoblasts in-vitro. The cells cultured onto titanium samples coated with ECM constituents showed faster osteoblastic differentiation and more efficient deposition of mineralized matrix in comparison with those onto uncoated substrates.

Abstract: In the present study, we have demonstrated that alginate and collagen sponge can act as scaffolds in order to support 3-dimensional structure for the differentiated bone marrow derived mesenchymal stem cells (BMSCs) during chondrogenesis in vitro and in vivo. The chondrogenic induced BMSCs were well distributed and differentiation in scaffolds system before implantation, then they produced sufficient ECM in the implants to form chondroid aggregates in vivo. In our opinion, well-differentiated BMSCs is a crucial feature of cartilage repair and only can be achieved in scaffold matrix. Furthermore, when dealing with cartilage defects, alginate seem to be superior to collagen sponge, and the combinational strategy of pre-induced BMSCs combined with alginate 3D-culture might be useful in improving conventional autologous cells transplantation or free-cells scaffolds.

Abstract: In our previous study, we discussed the possibility of differentiation activity measurement for rat mesenchymal stem cells (RMSC) by Dielectrophoretic (DEP) levitation. Consequently, it was found that the differentiation activity of the RMSC could be evaluated by DEP levitation without the differentiation induction. Thus, we discuss the possibility of differentiation activity evaluation by DEP levitation with cells other than the RMSC. Human mesenchymal stem cells (HMSC) and human adipose tissue-derived stem cells (ASC) were used as the sample cells. The dielectric characteristics (Re[K(ω)]) measurement, the Re[K(ω)] of both the HMSC and the ASC decreased with the increasing passage number. Moreover, to evaluate the differentiation activity of the HMSC and the ASC that had performed the osteoblast differentiation induction, the amount of Alkaline Phosphatase (ALP) was measured. Consequently, the ALP activity of both the HMSC and ASC decreased with increasing the passage number. Therefore, it was found that the differentiation activity of the HMSC and the ASC could be evaluated by measuring the Re[K(ω)] due to the relationship between the Re[K(ω)] and ALP activity.

Abstract: Functional scaffolds fabricated from biopolymers are of great importance for tissue engineering. In this paper, by mimicking the combination of two major components in Extracellular Matrix – collagen and polysaccharide respectively, we fabricated gelatin and chitosan hybrid sponge for cartilage tissue engineering. Extending previous results of gelatin/chitosan film showed that all the hybrid coating film (chitosan: gelatin= 4:1; 1:1; 1:4) can support the adhesion of ATDC5 that comparable to Tissue Culture Dish (TCD). More importantly, stem cell line ATDC5 on coating dish of chitosan: gelatin=1:4 showed enhanced differentiation rate than that on other films and TCD. For three dimensional scaffolds, we fabricated hybrid sponge scaffold of chitosan: gelatin=4:1, 2:1, 1:1, 1:2, 1:4 respectively. Morphological characterizations of the sponges showed that this kind of gelatin/chitosan hybrid scaffold is promising for application in cartilage tissue engineering.

Abstract: Osteoinductivity of hydroxyapatite (HA) was investigated using uncommitted pluripotent mouse stem cells, C3H10T1/2 in an in vitro differentiation assay. HA exhibited impressive ability to induce expression of osteo-specific genes in C3H10T1/2, including alkaline phosphatase (ALP), type I collagen (COL1) and osteocalcin (OCN); compared with its insignificant up-regulation of the same genes in osteoblast-like cells, Saos-2. HA osteoinductivity exhibited in C3H10T1/2 was comparable to that of a bone morphogenetic protein (BMP) with reference to up-regulating osteo-specific genes except the core binding factor 1 (Cbfa1, Runx). This result implies a difference in osteogenic induction pathway initiated by HA and BMP. HA osteoinductivity was also demonstrated in the stem cells culture using conditioned medium derived from cells cultured on HA substrates. The medium exhibited excellent ability to up-regulate ALP without the presence of HA and BMP. The result suggests that the HA can interact with the cells and generate potent inductive substance released into the medium. Such substance in turn is able to induce uncommitted cells to differentiate into the osteolineage.

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.