Implantation of osteogenic differentiated donor mesenchymal stem cells causes recruitment of host cells

The interaction between host and donor cells is believed to play an important role in osteogenesis. However, it is still unclear how donor osteogenic cells behave and interact with host cells in vivo. The purpose of this study was to track the interactions between transplanted osteogenic cells and host cells during osteogenesis. In vitro migration assay was carried out to investigate the ability of osteogenic differentiated human mesenchymal stem cells (O‐hMSCs) to recruit MSCs. At the in vivo level, O‐hMSCs were implanted subcutaneously or into skull defects in severe combined immunodeficient (SCID) mice. New bone formation was observed by micro‐CT and histological procedures. In situ hybridization (ISH) against human Alu sequences was performed to distinguish donor osteogenic cells from host cells. In vitro migration assay revealed an increased migration potential of MSCs by co‐culturing with O‐hMSCs. In agreement with the results of in vitro studies, ISH against human Alu sequences showed that host mouse MSCs migrated in large numbers into the transplantation site in response to O‐hMSCs. Interestingly, host cells recruited by O‐hMSCs were the major cell populations in newly formed bone tissues, indicating that O‐hMSCs can trigger and initiate osteogenesis when transplanted in orthotopic sites. The observations from this study demonstrated that in vitro induced O‐hMSCs were able to attract host MSCs in vivo and were involved in osteogenesis together with host cells, which may be of importance for bone tissue‐engineering applications. Copyright © 2012 John Wiley & Sons, Ltd.     

Osteogenic capacity of human BM‐MSCs,AT‐MSCs and their co‐cultures using HUVECs in FBS and PL supplemented media

Human bone marrow‐derived mesenchymal stem cells (BM‐MSCs) and human adipose tissue‐derived mesenchymal stem cells (AT‐MSCs) are the most frequently used stem cells in tissue engineering. Due to major clinical demands, it is necessary to find an optimally safe and efficient way for large‐scale expansion of these cells. Considering the nutritional source in the culture medium and method, this study aimed to analyze the effects of FBS‐ and PL‐supplemented media on osteogenesis in stem cell mono‐ and co‐cultures with human umbilical vein endothelial cells (HUVECs). Results showed that cell metabolic activity and proliferation increased in PL‐ compared to FBS‐supplemented media in mono‐ and co‐cultures for both BM‐MSCs and AT‐MSCs. In addition, calcium deposition was cell type dependent and decreased for BM‐MSCs but increased for AT‐MSCs in PL‐supplemented medium in both mono‐ and co‐cultures. Based on the effects of co‐cultures, BM‐MSCs/HUVECs enhanced osteogenesis compared to BM‐MSCs monocultures in both FBS‐ and PL‐supplemented media whereas AT‐MSCs/HUVECs showed similar results compared to AT‐MSCs monocultures. Copyright © 2013 John Wiley & Sons, Ltd.     

Control of dental-derived induced pluripotent stem cells through modified surfaces for dental application

Objective: The aim of this study is to investigate the behaviour of iPSc derived from dental stem cells in terms of initial adhesion, differentiation potential on differently surface-treated titanium disc.

Materials and methods: iPSc derived from human gingival fibroblasts (hGFs) were established using 4-reprogramming factors transduction with Sendai virus. The hGF-iPSc established in this study exhibited the morphology and growth properties similar to human embryonic stem (ES) cells and expressed pluripotency makers. Alkaline Phosphatase (AP) staining, Embryoid Body (EB) formation and in vitro differentiation and karyotyping further confirmed pluripotency of hGF-iPSc. Then, hGF-iPSc were cultured on machined- and Sandblasted and acid etched (SLA)-treated titanium discs with osteogenic induction medium and their morphological as well as quantitative changes according to different surface types were investigated using Alizrin Red S staining, Scanning electron microscopy (SEM), Flow cytometry and RT-PCR.

Results: Time-dependent and surface-dependent morphological changes as well as quantitative change in osteogenic differentiation of hGF-iPSc were identified and osteogenic gene expression of hGF-iPSc cultured on SLA-treated titanium disc found to be greater than machined titanium disc, suggesting the fate of hGF-iPSc may be determined by the characteristics of surface to which hGF-iPSc first adhere.

Conclusions: iPSc derived from dental stem cell can be one of the most promising and practical cell sources for personalized regenerative dentistry and their morphological change as well as quantitative change in osteogenic differentiation according to different surface types may be further utilized for future clinical application incorporated with dental implant.     

Molecular Outcome,Prediction, and Clinical Consequences of Splice Variants in COL1A1, Which Encodes the proα1(I) Chains of Type I Procollagen

Approximately 10%–20% of germline pathogenic variants alter mRNA splicing, with phenotypes often dependent on the stability of the mRNA produced by the mutant allele. To better understand the relationships between genotype, mRNA splicing, and phenotype, we examined clinical and molecular data from 243 probands with osteogenesis imperfecta (OI) representing 145 unique splicing variants within the type I procollagen gene, COL1A1. All individuals with IVSX‐1G>A mutations had OI type I because the substitution shifted the splice acceptor site 1 nt downstream and destabilized the mRNA. OI phenotypes were not consistent for any other splice variant identified. We sequenced all cDNA species from cultured dermal fibroblasts from 40 individuals to identify splice outcome and compared those results to splice predictions from Human Splice Finder (HSF), Spliceport (SP), and Automatic Splice Site and Exon Definition Analyses (ASSEDA). Software‐based splice predictions were correct in 42%, 55%, and 74% instances for HSF, SP, and ASSEDA, respectively. As molecular diagnostics move increasingly to DNA sequence analysis, the need to understand the effects of splice site variants will increase. These data demonstrate that caution must be exercised when using splice prediction software to predict splice outcome.     

Combined magnetic fields accelerate bone‐tendon junction injury healing through osteogenesis

The objective of this study was to explore the effect of combined magnetic fields (CMFs) on osteogenesis and the remodeling of newly formed bone at bone‐tendon (BT) junction. Forty‐eight mature rabbits in whom partial patellectomy was performed were used to establish a BT junction injury model at the patella‐patellar tendon (PPT) complex and were then allocated to CMF treatment group (CMF group) or placebo treatment group (control group). Daily CMF therapy was delivered continuously from post‐operative day 3 to weeks 4, 8, and 16. At each time point, the animals were sacrificed, and the PPT complexes were harvested for radiographic, histological, peripheral quantitative computed tomography, and micro‐computed tomography (micro‐CT) evaluation. The area, length, and bone mineral density of the newly formed bone in the CMF group were significantly greater than the control group at post‐operative weeks 8 and 16. The micro‐CT results showed that the newly formed bone in the CMF group contained more and thicker trabeculae than the control group at weeks 8 and 16. Histologically, the CMF group showed better remodeling of the BT junction. In conclusion, CMF treatment was able to accelerate osteogenesis during BT junction repair, thus facilitating the healing of BT junction injury.