Conditioned Medium Enhances Osteogenic Differentiation of Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells

BACKGROUND: Recent studies have shown that induced pluripotent stem cells (iPSCs) could be differentiated into mesenchymal stem cells (MSCs) with notable advantages over iPSCs per se. In order to promote the application of iPSC-MSCs for osteoregenerative medicine, the present study aimed to assess the ability of murine iPSC-MSCs to differentiate into osteoblast phenotype. METHODS: Osteogenic differentiation medium, blending mouse osteoblast-conditioned medium (CM) with basic medium (BM) at ratio 3:7, 5:5 and 7:3, were administered to iPSC-MSCs, respectively. After 14 days, differentiation was evaluated by lineage-specific morphology, histological stain, quantitative reverse transcription-polymerase chain reaction and immunostaining. RESULTS: The osteogenesis-related genes, alp, runx2, col1 and ocn expressions suggest that culture medium consisting of CM:BM at the ratio of 3:7 enhanced the osteogenic differentiation more than other concentrations that were tested. In addition, the alkaline phosphatase activity and osteogenic marker Runx2 expression demonstrate that the combination of CM and BM significantly enhanced the osteogenic differentiation of iPSC-MSCs. CONCLUSION: In summary, this study has shown that osteoblast-derived CM can dramatically enhance osteogenic differentiation of iPSC-MSCs toward osteoblasts. Results from this work will contribute to optimize the osteogenic induction conditions of iPSC-MSCs and will assist in the potential application of iPSC-MSCs for bone tissue engineering.

Osteoinductivity and performance of silk fibroin solution / 中国组织工程研究

BACKGROUND:Silk fibroin, as a kind of high-performance biomaterial, has been widely used to construct scaffolds in bone tissue engineering. However, whether silk fibroin itself holds osteoinductive ability has not been reported yet. OBJECTIVE:To investigate the impact of different concentrations of silk fibroin solution on the proliferation and differentiation of rat bone marrow mesenchymal stem cel s (BMSCs) in vitro. METHODS:Silk fibroin and BMSCs were respectively isolated from silkworm cocoon and rat tibia, and were identified. Then, BMSCs were cultured in different concentrations of silk fibroin solution (0.01%, 0.05%and 0.1%), and the cell proliferation and the alkaline phosphatase activity were detected at different time points. RESULTS AND CONCLUSION:FTIR spectra of the sample extracted from silkworm cocoon showed distinct absorption peaks at 1 653 (amide I), 1 530.5 (amide II) and 1 212.3 cm-1 (amide III), which could be confirmed to be silk fibroin. Thus generated BMSCs showed long fusiform or astral morphology, positive for representative markers (CD29, CD44 and CD90) relating to mesenchymal stem cells, and could differentiate into osteocytes, chondrocytes and adipocytes under specific induction conditions, which further confirmed the extracted cells were BMSCs. Compared with the control group (without silk fibroin), 0.05% silk fibroin not only significantly promoted the cell adhesion, migration and proliferation, but also enhanced the alkaline phosphatase activity (P<0.01). With the increasing of the silk fibroin concentrations, the osteodifferentiation capacity of the BMSCs was progressively improved within the range of 0-0.05%and then declined at 0.01%of silk fibroin solutions. These results suggest that silk fibroin can promote osteogenesis, thus providing scientific evidence for developing silk fibroin-based tissue-engineered scaffolds.

Prospect of stem cells in the treatment of hearing loss / 中国组织工程研究

OBJECTIVE: To review latest researches about the restoration of hair cells loss and injury by stem cells at home and abroad, and probe into the development in investigations about stem-cell substitutive therapy of auditory injury.DATA SOURCES: A computer-based online search was conducted in El-sevier database for English literatures about restoration of hearing impairment by stem cells published from January 1990 to May 2005 by using the key words of "stem cells and hearing cell regeneration".STUDY SELECTION: Collected literatures were screened. Inclusion criteria: ①Articles about hearing impairment and loss. ②Literatures on hearing impairment and restoration. ③Studies about stem-cell substitutive therapy of hearing impairment. Exclusion criteria: ①Literatures about the oncogenicity of stem cells.②Reviews and repetitive studies.DATA EXTRACTION: A total of 54 literatures about restoration of hearing loss were collected, and 17 papers were in accordance with the criteria,9 papers in which made analysis and evaluation on application of stem cells.DATA SYNTHESIS: Degeneration of inner ear cells, especially sensory hair cells and associated neurons, results in hearing impairment and balance disorders. Since the regeneration capacity of hair cells in cochlear and vestibule of mammals are limited, the loss of sensory hair cells is a major cause of neurosensory deafness, which can be hardly restored and regenerated by themselves. Cell substitutive therapy has a wide prospect in treatment of deafness, which is a hot issue in recent investigations of audition. The best method in transplantation treatment of deafness is to utilize otogenous stem cells. Recently, researchers have isolated embryo-like stem cells respectively from the organ of Corti in adult and newborn rats as well as vestibular utricles of adult mice. Therefore, the inner-ear stem cells are an important source of cells for remodeling the regeneration of hair cells and recovering the auditory function.CONCLUSION: Stem cells play an important role in treatment of hearing impairment induced by hair cells loss, which has a promising prospect in cell substitutive therapy as development of further investigation.