BACKGROUND AND OBJECTIVES: Coronary artery stenting actually shows a high efficacy in the treatment of coronary heart disease, but has the major limitation of restenosis. The ethylene-vinyl acetate copolymer (EVA), a biocompatible nondegradable copolymer, has been employed as a rate-controlling membrane in several drug delivery systems. Herein, the feasibility of an EVA-coated coronary stent was evaluated as a possible route for localized drug delivery. MATERIALS AND METHODS: A total of 15 rabbits were employed in this study. An uncoated stent was implanted into the non-diseased iliac artery in six rabbits, and an EVA-coated stent into a further nine. On the 30th day following the stent implantations, stented segments of the iliac arteries were removed for histological processing and morphometric analysis. RESULTS: The mean neointimal area of the uncoated and coated groups were 1.009 and 1.011 mm2 (p=0.56), respectively. No inflammatory cells were found in coated group. There were no apparent differences between the two groups. CONCLUSION: The results from this study have demonstrated that an EVA-coated coronary stent might be an appropriate method for the controlled-release of a drug.
Biological Availability* ; Coronary Disease ; Coronary Vessels ; Drug Delivery Systems ; Iliac Artery* ; Membranes ; Polyvinyls ; Rabbits ; Stents*

BACKGROUND: It is crucial, in the case of regenerating bone by tissue-engineering technique, that osteoblast progenitors are proliferated and induced to differentiate to osteoblasts sequentially at the proper time. Osteoblasts can be obtained from bone itself or from osteoblast progenitors in bone marrow, even though the amount of human marrow stromal cells in marrow aspirate is usually scanty. These cells, however, have been known demonstrate the potential to easily proliferate and differentiate in osteoblasts, chondroblasts or adipocytes according to different microenvironmental factors. We evaluated the effect of dexamethasone and 1,25(OH)2D3 on the proliferation, differentiation, and mineralization of human marrow stromal cells in vitro. METHODS: We used twelve bone marrow aspirates obtained from different healthy bone marrow donors. Culture plates were randomly divided into the following four experimental groups; group 1 was cultured with control medium only, group 2 with control medium containing 1,25(OH)2D3, group 3 with control medium containing dexamethasone, and group 4 with control medium containing both 1,25(OH)2D3 and dexamethasone. 3H-thymidine uptake, protein content of cell lysates, alkaline phosphatase activities and alkaline phosphatase histochemistries were measured. Alizarin Red-S staining and quantification of dissolved dye were also performed. RESULTS: Combined stimulation of marrow stromal cells with both 1,25(OH)2D3 and dexamethasone was found to be effective to maintain stable long-term culture of the cells and to increased differentiation and mineralization of the cells. Synthesis and mineralization of matrix were highest when the cells were stimulated with 1,25(OH)2D3 alone during the early culture phase. However, 1,25(OH)2D3 shortened the lifespan of the cells. Interestingly, mineralization was higher in female donor cells than in male donor cells when stimulated with dexamethasone alone or with both dexamethasone and 1,25(OH)2D3. Neither 1,25(OH)2D3 nor dexamethasone affected cell proliferation. CONCLUSION: Our results suggest that the synergistic effect of dexamethasone and 1,25(OH)2D3 is important in maintaining long-term culture and differentiation of human marrow stromal cells. It is preferable to administer 1,25(OH)2D3 after the attachment of cultured osteoblasts to biomaterials has been established, since it could shorten cell survival despite the great increase of mineralization at the early culture phase.
Adipocytes ; Alkaline Phosphatase ; Biocompatible Materials ; Bone Marrow* ; Cell Proliferation ; Cell Survival ; Chondrocytes ; Dexamethasone* ; Female ; Humans* ; Male ; Mesenchymal Stromal Cells* ; Osteoblasts ; Stromal Cells ; Tissue Donors ; Tissue Engineering

PURPOSE: To characterize the chondrogenic potential of human mesenchymal stem cells (MSCs) in porous polymeric scaffolds by poly (glycolic acid) (PGA) as three-dimensional constructs to facilitate chondrogenic differentiation. METHODS: Human MSCs were isolated by percoll gradient method and adherent cell cultures were obtained. Isolated MSCs were characterized with CD 34 and Sca-1 antibodies using flow cytometry. MSCs were seeded in the PGA polymeric scaffolds for 28 days in a specialized defined medium. The control group was examined without the specialized defined medium. The chondrogenesis of MSCs-seeded polymer scaffolds culture was assessed by histology, RT-PCR and 35S-sulfate incorporation. RESULTS: Flow cytometry result showed that CD 34 was negative and Sca-1 was 93+/-10% positive. By the histological analysis from Safranin-O staining, it was confirmed that the chondrogenic differentiated human MSCs expressed chondrocyte-like morphologies. We also observed that type II collagen was expressed by RT-PCR. The degree of proteoglycan synthesis was higher in the experimental group than the control group. CONCLUSION: We have demonstrated that the biodegradable porous polymeric scaffolds and the specialized defined medium is able to provide three-dimensional constructs for inducing chondrogenic differentiation of human MSCs.
Antibodies ; Cell Culture Techniques ; Chondrogenesis ; Collagen Type II ; Flow Cytometry ; Humans* ; Mesenchymal Stromal Cells* ; Polymers* ; Proteoglycans

PURPOSE: To evaluate the possibility that human muscle derived stem cells (hMDSCs) can be differentiated into neurons in vitro. MATERIAL AND METHODS: Muscle derived stem cells were isolated from the hamstring muscles during the anterior cruciate ligament reconstruction by preplate technique. For the characterization of these cells, desmin staining, CD 34, Sca-1, CD 29 using the Flow cytometry were performed. In the experimental group, neuronal induction media was added to differentiate hMDSCs to neuronal cells. These cells were evaluated by neuronal markers such as neuron-specific enolase (NSE), neurofilament (NF), TrkA using immunocytochemistry. For the control group, no induction media was added. Statstical analyses were performed by use of Kruskal-Wallis H test and Student-Newman-Keuls test (P<0.01). RESULT: Desmin staining was positive in 92.3+/-6%. Flow cytometry was negative for CD 34 and Sca-1. However it was positive for CD 29. (69.4+/-10%). The immunocytochemical result revealed NSE, NF and TrkA positive with 63.2+/-2.3%, 59.2+/-2.5%, 55+/-2.4% respectively. However, these were negative in the control group. CONCLUSION: Our observations indicate that hMDSCs have the capacity to differentiate into neurons in a specialized culture media.
Anterior Cruciate Ligament Reconstruction ; Culture Media ; Desmin ; Flow Cytometry ; Humans* ; Immunohistochemistry ; Muscles ; Neurons* ; Phosphopyruvate Hydratase ; Stem Cells*