Tehran University Medical Journal

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Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background: Human bone marrow mesenchymal stem cells (hMSCs) can differentiate into several types of mesenchymal cells, including osteocytes, chondrocytes, and adipocytes, but can also differentiate into non-mesenchymal cells, such as neural cells, under appropriate experimental conditions. Until now, many protocols for inducing neuro-differentiation in MSCs in vitro have been reported. In this study, we induced differentiation into neural phenotype in the hMSCs population by new protocol. In this treatment, hMSCs could express neural markers more than other reports, associating with remarkable morphological modifications. 
Methods: The Bone marrow specimens were aspirated from the iliac crest of normal men. hMSCs were isolated and cultured in DMEM containing 15% FBS. Between 4-8 passages conversion of hMSCs into neurosphere-like structures and induction this cells to nerve precursors in the low-attachment plastic bacterial dishes with bFGF, EGF & RA were initiated. After seven days terminal neural differentiation was initiated by plating the cells on poly-L-ornithin and Laminin coated dishes. Cells were differentiated for 7-14 days. We used flowcytometry and immunocytochemistry analysis for assessment of specific neural stem cell markers in induced cells.
Results: Flowcytometery analysis showed that after induction, 90±2.52 percent of the cells will express neuronal marker Nestin and about 41±1 percent of the cells will express Tuj-1 and about 67±1.05 percent of the cells will express GFAP. Immunocytochemistry and morphologically modifications revealed the same results.
Conclusion: Results showed that hMSCs treatment with bFGF, EGF & RA the number of Tuj1 neurons. These data confirmed that hMSCs can exhibit neuronal differentiation potential in vitro, depending on the protocols of inducement.

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Background: Human embryonic stem cells (hESCs) are capable of self-renewal and large-scale expansion. They also have the capacity to differentiate into a variety of cell types including liver, cardiac and neuron cells. However, it is not yet clear whether hESCs can differentiate to hemangioblasts under in-vitro conditions. Hemangioblasts are bipotential progenitors that can generate hematopoietic lineages and endothelial cells. The aim of this study was to identify the potential of human Royan H5 embryonic stem cells in differentiating into hemangioblast cells.

Methods: HESCs were cultured at suspension system in DMEM/F12 supplemented with bFGF. 7-day old cells differentiated into blast cells under defined condition consisting of hematopoietic cytokines including BMP4, VEGF, etc. Blast cell markers kinase insert domain receptor (KDR), CD31, and CD34 were evaluated by flow cytometry and blast gene expressions (TAL-1, Runx-1 and CD34) were detected by qRT-PCR. Clonogenic assays were performed in semisolid medium by colony forming unit-assays.

Results: The hESCs (Royan H5) had the capacity of differentiating into hemangioblast cells. We could detect colonies that expressed 79%±12.5 KDR+, 5.6%±2.8 CD31+-CD34+ and 6%±2.12 KDR+-CD31+ on day 8 in the hESCs. Up-regulation of TAL-1, Runx-1 and CD34 occurred during hemangioblast commitment (P≤0.05 and P≤0.01, respectively). Moreover, hemangioblast cells generated mixed-type and endothelial-like colonies in semi-solid media.

Conclusion: Our results showed that hESCs (Royan H5) were able to differentiate into hemangioblasts under in-vitro conditions. The hemangioblasts had the potential to generate two non-adherent (Mixed-type) and adherent (endothelial-like) cell populations.

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Embryonic stem cells are pluripotent stem cells which have the ability to indefinitely self-renew and differentiate into all differentiated cells of the body. Regarding their two main properties (unlimited self-renewal and multi-lineage differentiation), these cells have various biomedical applications in basic research and cell based therapy. Because the transplantation of differentiated cells that are derived from embryonic stem cells is allogenic, they face the problem of immune rejection following the transplantation of embryonic stem cell-derived cells into patients. In 2006, researchers from Japan reported the derivation of a new type of pluripotent stem cells which could overcome the problem of immune rejection that is associated with the application of embryonic stem cells. They designated these cells as induced pluripotent stem (iPS) cells, because their production was ‘induced’ from differentiated somatic cells using a combination of four embryonic stem cell-associated transcription factors. Importantly, these pluripotent stem cells exhibit all the key features of embryonic stem cells including unlimited self-renewal and multi-lineage differentiation potential, and can pass the most stringent test of pluripotency which is known as the tetraploid (4n) complementation. Hence, in addition to bypassing the problem of immune rejection, iPS cells have all of the potential applications of embryonic stem cells, including in developmental studies, toxicology research, drug discovery and disease modeling. Also, considering that they could be generated from patient’s own cells, iPS cells hold great promise in the future of patient-specific cell replacement therapies using pluripotent stem cells. In this review article, we will present a comprehensive review on the how and why of the generation of iPS cell from somatic cells of the body and discuss how they should be characterized in terms of morphologically, pluripotent stem cell behavior, and the molecular signature. In addition, their medical applications as well as some of the considerations and future challenges in their use will be discussed.