The Effects of Substrates and Hydrostatic Pressure on Differentiation of Mesenchymal Stem Cell / 대한정형외과연구학회지

PURPOSE: This study investigated the potential of dual differentiation of stem cells into osteo- and chodrogenesis depending on scaffold type even in the same environment. MATERIALS AND METHODS: For the part of the cartilage tissue section, MSCs were suspended in alginate solution and bead droplets were made using 23G syringe. For the bone tissue section, PCL/HA scaffolds were made using the bio-plotting system followed by seeding mesenchymal stem cells (MSCs) onto the scaffolds. Scaffolds with MSCs were cultured in cocktail media containing osteogenic and chondrogenic growth factors for up to 21 days. To provide mechanical environments which articular cartilage experiences in-vivo, intermittent hydrostatic pressure (IHP) was engaged. Various cellular responses were assessed: the quantitative analysis of DNA contents, GAG contents, ALP activities and immunofluorescence. RESULTS: We found that IHP promoted MSCs differentiation into the targeted cell types. That is, MSCs in alginate scaffolds were able to be differentiated into chondrocytes, while those onto PCL/HA scaffolds were able to be differentiated into osteoblasts. CONCLUSION: Depending on the scaffold characteristics MSCs can be differentiated into bone cells or chondrocytes. This technique can provide a cue for the treatment of osteochondral defects utilizing tissue engineering.

The Effects of Substrates and Hydrostatic Pressure on Differentiation of Mesenchymal Stem Cell / 대한정형외과연구학회지

PURPOSE: This study investigated the potential of dual differentiation of stem cells into osteo- and chodrogenesis depending on scaffold type even in the same environment. MATERIALS AND METHODS: For the part of the cartilage tissue section, MSCs were suspended in alginate solution and bead droplets were made using 23G syringe. For the bone tissue section, PCL/HA scaffolds were made using the bio-plotting system followed by seeding mesenchymal stem cells (MSCs) onto the scaffolds. Scaffolds with MSCs were cultured in cocktail media containing osteogenic and chondrogenic growth factors for up to 21 days. To provide mechanical environments which articular cartilage experiences in-vivo, intermittent hydrostatic pressure (IHP) was engaged. Various cellular responses were assessed: the quantitative analysis of DNA contents, GAG contents, ALP activities and immunofluorescence. RESULTS: We found that IHP promoted MSCs differentiation into the targeted cell types. That is, MSCs in alginate scaffolds were able to be differentiated into chondrocytes, while those onto PCL/HA scaffolds were able to be differentiated into osteoblasts. CONCLUSION: Depending on the scaffold characteristics MSCs can be differentiated into bone cells or chondrocytes. This technique can provide a cue for the treatment of osteochondral defects utilizing tissue engineering.

The effect of angiogenic factors with HA/PCL scaffold containing matrigel in a rat calvarial defect model / 동물의과학연구지

The current study was conducted in order to investigate bone formation using matrigel and angiogenic factors with HA and poly epsilon-caprolactone (HA/PCL) in a rat calvarial defect model. Calvarial defect formation was surgically created in Sprague Dawley rats (n=36). Rats in the control group (CD group, n=6) did not receive a graft. The HA/PCL scaffold was grafted with matrigel (M-HA/PCL group, n=6) or without matrigel (HA/PCL group, n=6); and 100 ng of vascular endothelial growth factor with HA/PCL scaffold containing matrigel (VEGF100 group, n=6), 100 ng (PDGF100 group, n=6) and 300 ng (PDGF300 group, n=6) of PDGF with HA/PCL scaffold containing matrigel were grafted in calvarial defects, respectively. Four weeks after surgery, bone formation was evaluated with micro computed tomography (micro CT) scanning, and histologically. According to the results, bone mineral density was significantly increased in the VEGF100, PDGF100, and PDGF300 groups compared to the HA/PCL group, in which angiogenic factors were not applied. In histological evaluation, more new bone formation around scaffolds was observed in the PDGF100 and the PDGF300 groups, compared with the VEGF100 group. Thus, the results indicate that HA/PCL containing matrigel with VEGF and PDGF is an effective grafting material for enhancement of bone formation in critical-sized bone defects. Especially, due to its price and capacity for bone formation, PDGF may be more effective than VEGF.

Fabrication of an alpha-lipoic acid-eluting poly-(D,L-lactide-co-caprolactone) cuff for the inhibition of neointimal formation

The purpose of this study was to develop a novel polymer cuff for the local delivery of alpha-lipoic acid (ALA) to inhibit neointimal formation in vivo. The polymer cuff was fabricated by incorporating the ALA into poly-(D,L-lactide-co-caprolactone) 40:60 (PLC), with or without methoxy polyethylene glycol (MethoxyPEG). The release kinetics of ALA and in vitro degradation by hydrolysis were analyzed by HPLC and field emission scanning electron microscopy (FE-SEM), respectively. In vivo evaluation of the effect of the ALA-containing polymer cuff was carried out using a rat femoral artery cuff injury model. At 24 h, 48% or 87% of the ALA was released from PCL cuffs with or without MethoxyPEG. FE-SEM results indicated that ALA was blended homogenously in the PLC with MethoxyPEG, whereas ALA was distributed on the surface of the PLC cuff without MethoxyPEG. The PLC cuff with MethoxyPEG showed prolonged and controlled release of ALA in PBS, in contrast to the PLC cuff without MethoxyPEG. Both ALA-containing polymer cuffs had a significant effect on the inhibition of neointimal formation in rat femoral artery. Novel ALA-containing polymer cuffs made of PLC were found to be biocompatible and effective in inhibiting neointimal formation in vivo. Polymer cuffs containing MethoxyPEG allowed the release of ALA for one additional week, and the rate of drug release from the PLC could be controlled by changing the composition of the polymer. These findings demonstrate that polymer cuffs may be an easy tool for the evaluation of anti-restenotic agents in animal models.