Papers by Keyword: Mesenchymal Stem Cell (MSC)

Abstract: Background Numerous studies have provided data on the efficacy of ADSCs, supporting their use in current and future clinical applications. This is the first study to our knowledge, which aims at comparing the cell viability and the absolute number of mesenchymal stem cells and ADSCs from three different approaches of preparing adipose tissue for autologous transplantation. Patients & MethodsAdipose tissue was taken from the hip/thigh region of 8 female donors undergoing liposuction. From every patient, there was sent three different fat samples: lipoaspirated fat decanted (A), lipoaspirated fat prepared by normal saline washing (B) and stromal enriched lipograft (C). Multi-parameter flow cytometry to determine the absolute number and viability of ADSCs was performed. ResultsThe mean absolute cell counts per gram of adipose tissue were 8.33x10⁶ in samples A and 5.97x10⁶ in sample C. In B samples the mean absolute cell counts per gram of adipose tissue were 2.13x10⁶. The presence of ADSCs specific markers in all the C samples showed high expression (> 95%) in the positive markers and low expression (< 2%) in the negative markers and are essential to validate the purity of adipose stem cells in a sample. ConclusionThe results obtained from the analysis of eight different donors of lipoaspirate indicate that the highest absolute number of viable adipose derived stem cells is found in the Stromal Enriched Lipograft (sample C). Their purity was confirmed by the high expression (> 95%) in the positive markers and low expression (< 2%) in the negative markers.

Abstract: The aim of this study is to evaluate the injectable cross-linked chitosan (CS) microparticles (MPs) to apply for biomedical applications specifically for bone regeneration. The CS MPs were fabricated by emulsification method and formed the cross-links between the amide groups in the CS and phosphate groups in the sodium tripolyphosphate (TPP) ionic cross-linking agent. The MPS were analyzed for morphology by Scanning Electron Microscope (SEM). The fabricated CS MPs were in the spherical shape with the size range of 20-100 m. These CS MPs were analyzed for biodegradation by immersing in phosphate buffered saline (PBS, pH = 7.4) at 37°C for 30 weeks. The biodegradation of CS MPs in PBS was initiated at week 25. Mesenchymal stem cells (MSCs) were harvested from the bone marrow of mice tibia and femurs. The MSC attachment on CS MPs was tested using LIVE/DEAD cell sassy with a Fluorescence Microscope. The murine MSCs attachment onto CS MPs at day 2 was confirmed by visualizing fluorescence images. The CS MPs were also analyzed for the injectability and retainability at the site using a subcutaneous injection in a rat model. The fabricated CS MPs possess injectability, biodegradability and biocompatibility. Therefore, these CS MPs have a great potential to apply for various biomedical applications including bone regeneration by injection.

Abstract: Dental pulp cell research might open a promising application in tooth tissue regeneration. The aim of this study is to establish a protocol for in vitro culture the human dental pulp stem cells to apply in tissue engineering. Human premolar and impacted third molars were collected and disinfected. Dental pulp fragments were cultured with Dulbecco's Modified Eagle Medium: Nutrient Mixture F-12 (DMEM/F12) medium supplemented with 10% Fetal Bovine Serum (FBS). Dental pulp stem cells (DPSCs) were identified using proliferation assay, RT-PCR and flow cytometry. Growth of DPSCs on dentin surface was assessed by MTT assay. The study showed that we successfully isolated, cultured and characterized dental pulp cells by outgrowth method. Cultured population of cells expressed in high level of Oct4, CD146, CD90, CD44. DPSCs proliferated on chemically and mechanically treated dentin surface. This research provides important information and a basis for further investigations to establish dental tissue engineering protocols.

Abstract: Aseptic loosening induced by wear debris particles of artificial joint is characterized by a considerable suppression of osteogenesis. The objective of this investigation was to determine the effect of different-sized titanium particle on protein synthesis, and mineralization in bone marrow–derived mesenchymal stem cells(BMSCs) induced toward osteogenic differentiation in vitro. Rat bone marrow–derived mesenchymal stem cells (rBMSCs) induced toward osteogenesis were cultured in the presence or absence of titanium particles in varied size, 0.9µm, 2.7µm, 6.9µm, respectively. Flow cytometry characterization of rBMSCs proved 99% homogeneity by using with cell-surface antibody. The bone matrix protein synthesis evaluation showed that three size groups of titanium particles could suppress early, middle, and late markers of the osteogenic lineage, i.e., alkaline phosphatase activity, C-terminal type I procollagen and osteocalcin secretion repectively, in a dose- and time-dependent manner. The least detrimental particle size group was 0.9 μm, which is a reasonable finding as this group is more susceptible to phagocytosis due to smaller size. The cell-mediated matrix mineralization in terminally differentiated cultures by Alizarin Red S assay revealed a reduction in the number and area of mineralizing nodules, even mineralization calcium concentration in BMSCs cultures after titanium particles treatment. Collectively, the data suggest that different size titanium particles alters osteogenic differentiation in BMSCs cultures during lineage progression and provide further insight into wear debris-induced reduced bone formation.

Abstract: To stimulate bone regeneration, the design of bioactive implants is a great challenge in current orthopedic research. We reasoned that implants should be suitable both to stimulate osteogenic differentiation of mesenchymal stem cells and prevent infections at the site of implantation. Therefore, we focus on copper ions, which are known to exert antimicrobial effects. On the other hand, copper is essential for the cell physiology, including the formation of the extracellular matrix. We studied the influence of copper ions on mesenchymal stem cells at various concentrations and identified the limits of copper concentrations for cell survival. Below the critical concentration for cell survival we analysed proliferation and osteogenic differentiation of the cells in the presence of copper ions. We found that copper stimulated the proliferation of the mesemchymal stem cells at 0.1 mM. Osteogenic differentiation decreased after 14 days at a concentration of 0.05 - 0.1 mM copper ions in osteogenic medium measured by the expression of osteogenic proteins, like alkaline phosphatase (ALP), bone sialoprotein (BSP) and collagen I (COL). We argue that at the implant surface a higher concentration of copper could prevent biofilm formation of bacteria and physiological concentrations in the vicinity of the implant would stimulate stem cell expansion. Together, copper is an interesting agent to control both bacteria and stem cells in the field of implant technology.

Abstract: The development of skin tissue engineering provides a noninvasive method for skin restoration. Unfortunately, the lack of a vascular plexus leads to greater time for vascularization compared with native skin autografts and contributes to graft failure. Our purpose was to construct tissue-engineered skin with VEGF- modified human bone marrow mesenchymal stem cells (hMSCs) as well as acellular dermal matrix(ADM) in vitro , Thus by increased vascular endothelial growth factor expression, which could prospectively improve vascularization of tissue-engineered skin for wound healing applications. To reach this aim, hMSCs were isolated and cultured with density gradient centrifugation combined with attachment culture method in vitro. Liposome- mediated gene transfer was used to generate a population of hMSCs overexpressing the gene encoding VEGF165. Then VEGF- modified hMSCs were seeded onto the surface of ADM. The experimental results showed that ADM we prepared has good compatibility with MSCs, the cells in ADM grew and proliferated well in vitro and the tissue - engineered skin with VEGF- modified hMSCs and ADM has been successfully constructed.

Abstract: Degenerative disc disease has been implicated as a major component of spine pathology. However, though biological repair of the degenerate disc would be the ideal treatment, there is a lack of a universally accepted scaffold for tissue engineering of intervertebral discs (IVD) and little is known of how to differentiate mesenchymal stem cells (MSCs) to a disc-like phenotype. We show that 2.5% Protasan® UP G213 cross-linked to 5% genipin might be a promising scaffold for disc tissue engineering. Furthermore, we have developed extremely N-rich plasma polymer layers, which we call "PPE:N" (N-doped plasma-polymerized ethylene, containing up to 36% [N]). We show that PPE:N almost completely suppresses the expression not only of type X collagen, but also of osteogenic marker genes such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). In contrast, neither aggrecan nor types 1 collagen expression were significantly affected. These results indicate that PPE:N coatings may be suitable surfaces for inducing MSCs to a chondrocyte or disc-like phenotype for tissue engineering of cartilage or IVDs, in which hypertrophy and osteogenesis are suppressed.

Abstract: Mesenchymal stem cells are multipotential cells capable of differentiating into osteoblasts, chondrocytes, adipocytes, tenocytes, and myoblasts. Wharton’s jelly consists of stem cells that are a rich source of primitive multipotent mesenchymal cells. Demineralized bone matrix (DBM) has been widely utilized as a biomaterial to promote new bone formation. We isolate and characterize umbilical cord Wharton’s Jelly-derived mesenchymal stem (UCMS) cells derived from Wharton’s jelly and examine the biological activity of DBM in this cell line. Osteoblast differentiation of the UCMS cells was determined using alkaline phosphatase (ALP) activity assay. To examine differential gene expression during osteogenic differentiation, total RNA was isolated from UCMS cells in the absence or presence of DBM on day7 and analyzed using osteogenesis cDNA gene array. The selected genes were verified using reverse transcriptase-polymerase chain reaction (RT-PCR) analyses. Wharton’s jelly derived cells could differentiate along an osteogenic lineage after treatment of DBM. The ALP activity assay showed that human UCMS cells could differentiate into osteogenic lineage. Gene expression of human UCMS cells treated with DBM for 7 days was analyzed by using cDNA array and RT-PCR analyses. We found that expression of RUNX2 and SMAD2 was upregulated whereas SMAD7 expression was downregulated as confirmed by RT-PCR. UCMS cells from a Wharton’s jelly of human umbilical cord could express osteogenesis genes for treatment with DBM. Wharton’s jelly from umbilical cord is a new source of mesenchymal stem cells that are readily available for application to bone tissue engineering.

Abstract: Porous calcium phosphate cement (CPC) scaffolds were successfully fabricated utilizing particle-leaching method. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffolds and the proliferation and differentiation of MSCs into osteoblastic phenotype were determined using MTT assay, ALP activity and ESEM. The results revealed that the CPC scaffolds were biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity of the scaffolds were investigated. Both pure scaffolds and MSCs/scaffold constructs were implanted in rabbit mandibles and studied histologically. The results showed that CPC scaffolds exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffolds dramatically enhanced the efficiency of new bone formation initially.

Abstract: The decrease in bone mass caused by wear debris-induced osteolysis could have been compensated through osteoblasts secreting enough new bone matrix. However, the normal osteoblastic population depends on the regular differentiation of their progenitor cells, the bone marrow mesenchymal stem cells (BMSCs). It is not possible to predict whether wear particles will affect the BMSCs’ viability, and subsequently their differentiation. Furthermore, little is known about the extent to which the sizes of the wear particles loading can impact the viability the most. This study has, therefore, concentrated on the potential mechanism for rat BMSCs’ (rBMSCs) viability influenced by different-sized titanium particle (Ti) loading in vitro.rBMSCs were harvested and loaded with circular Ti particles having three different mean diameters, 0.9, 2.7 and 6.9 .m respectively. The results showed that different-sized titanium particles all inhibited rBMSCs’ proliferation and induced rBMSCs’ apoptosis response , but this influence varied with the size of the Ti particles, their concentration and the duration of loading. The smallest Ti particles (0.9.m) exhibited the earliest and largest suppression on the proliferation and the most powerful induction on the apoptotic response of rBMSCs. qRT-PCR analysis demonstrated that those apoptotic effects were association with the abnormal accentuation of inducible nitric oxide synthase(iNOS) activity. The size of titanium particles generated through wear of a prosthetic device and the osteoblastic progenitor BMSCs may be both important considerations in the development of superior implant technology.