In clinical studies and animal models, low-intensity ultrasound (US) promotes fracture repair and increases mechanical strength. US also promotes cartilage healing by increasing glycosaminoglycan synthesis of chondrocytes. As mesenchymal stem cells (MSCs) have the ability to differentiate into chondrocytes, US may promote their differentiation. Here, we evaluated the effects of US on the differentiation of MSCs toward chondrocytes and cartilage matrix formation. When human MSCs cultured in pellets were treated with transforming growth factor beta (TGF-beta, 10 ng/mL), they differentiated into chondrocytes as assessed by alcian blue staining and immunostaining for aggrecan, but nontreated cell pellets did not. Furthermore, when low-intensity US was applied for 20 min every day to the TGF-beta-treated cell pellets, chondrocyte differentiation was enhanced. Biochemically, aggrecan deposition was increased by 2.9- and 8.7-fold by treatment with TGF-beta alone, and with both TGF-beta and US, respectively. In contrast, cell proliferation and total protein amount appeared unaffected by these treatments. These results indicate that low-intensity US enhances TGF-beta-mediated chondrocyte differentiation of MSCs in pellet culture and that application of US may facilitate larger preparations of chondrocytes and the formation of mature cartilage tissue.
We developed a gold-coated membrane substrate modified with an oligopeptide layer that can be used to grow and subsequently detach a thick cell sheet through an electrochemical reaction. The oligopeptide CCRRGDWLC was designed to contain a cell adhesive domain (RGD) in the center and cysteine residues at both terminals. Cysteine contains a thiol group that forms a gold–thiolate bond on a gold surface. Cells attached to gold-coated membrane substrates via the oligopeptide layer were readily and noninvasively detached by applying a negative electrical potential to cleave the gold–thiolate bond. Because of the effective oxygen supply, fibroblasts vigorously grew on the membrane substrate and the thickness of the cell sheets was ∼60 μm at 14 days of culture, which was 2.9-fold greater than that of cells grown on a conventional culture dish. The cell sheets were detached after 7 min of electrical potential application. Using this approach, five layers of cell sheets were stacked sequentially with thicknesses reaching >200 μm. This approach was also beneficial for rapidly and readily transplanting cell sheets. Grafted cell sheets secreted collagen and remained at the transplanted site for at least 2 months after transplantation. This simple electrochemical cell sheet engineering technology is a promising tool for tissue engineering and regenerative medicine applications.
In this research, we examined the effect on wound healing applying basic fibroblast growth factor (b-FGF) that is approved for clinical use to enhance wound healing and human deciduous teeth dental pulp cells (hDPCs) in clinics, but that have been attracting attention as a novel stem cell source in recent years. Human deciduous teeth were harvested from healthy volunteers, and hDPCs were isolated. We used a nude mouse full-thickness skin defect model and evaluated wound healing by macroscopic view and histologic and histomorphometric analysis. The mice were randomly divided into 4 groups: phosphate-buffered saline-treated group (control group), b-FGF-treated group (b-FGF group), hDPC-treated group (hDPC group), and hDPC and b-FGF-treated group (hDPC/b-FGF group). Basic fibroblast growth factor and hDPC groups accelerated wound healing compared with the control group. There was no statistically significant difference in wound healing observed between the hDPC and b-FGF groups. The hDPC/b-FGF group demonstrated accelerated wound healing compared with other groups. At day 14, PKH26-positive cells were surrounded by human type I collagen in hDPC and hDPC/b-FGF groups in immunohistologic evaluation. Significantly increased collagen fibril areas in wound tissues were observed in b-FGF, hDPC, and hDPC/b-FGF groups as compared with the control group at days 7 and 14. Our results showed that the hDPC/b-FGF group significantly promotes wound healing compared with other groups. This study implies that deciduous teeth that are currently considered as medical spare parts might offer a unique stem cell resource for potential of new cell therapies for wound healing in combination with b-FGF.
Skin-derived precursor cells promoted diabetic wound healings through vasculogenesis at the early stage of wound healing. Skin-derived precursor cells are a possible therapeutic tool for diabetic impaired wound healing.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.