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Background: Differentiation ofmesenchymal stem cells (MSCs) to hepatocyte-like cells could be associated with development of liver function factors. The impact of differentiation-dependent changes on DNA integrity is not well understood. In this study, hepatocytes and their progenitor stem cells were treated with aflatoxin B1 (AFB1) and amplification of selected genes linked to DNA damage was examined. Methods: MSCs and CD34+ cells isolated from umbilical cord blood (UCB) were treated with AFB1 (0, 2.5, 10 and 20 µM) in selective media supporting the hepatocyte differentiation. After 24 htreatment the DNA damage (Comet assay) and amplification rates ofP53 and β-globin genes were measured using real time polymerase chain reaction (QPCR). Results:The results show that AFB1 treatments resulted in a concentration- dependent increase in the DNA damage and suppression of the specific gene amplification. The extent of DNA damage was significantly greater in hepatocytes differentiated from MSCs when compared to those obtained from CD34+ cells. The effects of AFB1 on the rate of selected gene amplification in QPCR showed that the lesions (expressed as lesions/10 kb) in P53 and β-globin genes was significantly greater in hepatocytes derived from MSCs as compared to the cells derived from CD34+ cells. Conclusions: These data together with the results of cytochrome P450 (CYP3A4) expression in the cells suggest that the non-differentiated stem cells are probably less vulnerable to genotoxic agents as compared to hepatocytes differentiated from them.

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Background: In recent years we have successfully adopted an in vitro hepatogenic differentiation of mesenchymal stem cells (MSCs). In this protocol the biologically active hepatocyte-like cells were differentiated from the stem cells isolated from either bone marrow or umbilical cord blood (UCB) samples. The aim of the present study was to compare the efficiency of the hepatogenic differentiation of MSCs isolated from UCB and MSCs. Methods: Differentiation process of MSCs was carried out in a selective medium supporting hepatogenic differentiation for 3 weeks. Then using specific markers we have examined the hepatocyte formation following hepatogenic differentiation of the stem cells. Hepatogenic markers namely albumin, α-fetoprotein (AFP) and cytochrome P450 3A4 (CYP3A4) were monitored at different time intervals during differentiation. Results: Transdifferentiation of the UCB and bone marrow MSCs was also characterized by measuring albumin, AFP and CYP3A4 at mRNA levels using reverse transcription polymerase chain reaction (RT-PCR). AFP was expressed in the undifferentiated UCB-MSCs and increased on day 21 of differentiation. However, AFP was not detected in the undifferentiated bone marrow MSCs. But, AFP expression started during the first week of differentiation. Albumin expression was detected in hepatocytes from UCB as well as bone marrow. The expression of albumin and its secretion from hepatocyte prepared from bone marrow appeared earlier compared to the cells derived from UCB. Metabolic function of the hepatocytes evaluated by secretion of albumin in the culture media was also similar in the cells isolated from both the sources. Conclusions: The differentiation potential of MSCs derived from human UCB and bone marrow under in vitro condition is comparable. However, it appears that there is time-dependent difference in the onset of expression of liver specific markers particularly albumin synthesis in hepatocytes derived from different stem cells.

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Background: Osteoarthritis (OA) has been recognized, as the most common inflammatory disease in the world. Adipose Stem Cells (ASCs), as a new feasible source with high numbers of stem cells and proliferative capacity have been used for regenerative medicine. Based immunomodulatory and chondrogenic properties of ASCs, this study aimed to assess intra articular injection of ASC effect on improvement of osteoarthritis signs. Methods and Materials: Adipose tissue samples were obtained from subcutaneous of abdomen. ASCs were isolated and cultured for at least three passages in culture media containing autologous serum and expanded them to 15-20 × 10⁶ cell. The morphology and proliferative potency of ASCs were determined. Immuno phenotype characteristics of ASCs were analyzed by flow-cytometry. Then cell suspensions were injected into knee articular spaces. After 6 months the function of knee was assessed by WOMAC, KOOS, Lysholm and Lequesne indexes. Results: The results of this study showed that homogenous spindle-shape ASCs expanded rapidly with low doubling time. The low expression of CD14 and CD45 indicated that ASCs are non hematopoietic cells and expressed high percentages of CD44, CD105 and CD90. Our results showed that injected ASCs were effective in improvement of OA by scoring systems for evaluation of pain, joint movements and daily physical activities were significantly changed due to injection of stem cells. Osteoarthritis severity indexes means of WOMAC and Lequesne were decreased from 53 to 12.3 and 15.1 to 2.1 respectively. Also osteoarthritis improvement indexes Lysholm & KOOS means were significantly increased from 35 to 15.1 and 70 to 126.7 respectively. In six months follow up of intra articular injection of ASCs, we observed no local or systemic side effect. After ASCs injection, walking distance considerably increased. The flexion angle of knee improved by 20-30 degrees compares to before of treatment. Conclusion: Autologous ASCs injection could be resulted in increasing of knee function, alleviated of pain and quality of life improvement.

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  Cancer stem cells (CSC) are the tumor-associated cells existed within tumors or hematological cancers which share characteristics similar to normal stem cells. The common characteristics of a normal stem cell and a CSC are their differentiation capacity and self-renewal in tumors. The expression pattern of CSC markers differs depending on the type and location of cancers. CD molecules are probably the most common biomarkers for CSCs. CD molecules such as CD133, CD24, CD44, CD138 and similar CD molecules are well known markers for identification of CSCs. In addition, ATP-Binding Cassette (ABC) transporters such as ABCG2 and ABCB5 as well as EpCAM, ALDH1 and CXCR4 have been used to identify certain CSCs. Therefore these markers may be considered specific for better identification and diagnosis of a specific tumor. Currently studies are in progress to find new cell surface markers which can distinguish specific markers from other markers for isolation and characterization of CSCs. The future of this area of research is promising in developing novel prognostic assays and therapeutic approaches based on cellular and signaling functions of these markers.

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Stem cell therapy has been introduced as an innovative and promising treatment in Ischemic diseases. Mesenchymal stem cells are considered for cell therapy to some extent due to their immunemodulatory, differentiation potential, feasibility of isolation and proliferation properties. Stem cells, after transplantation, often encounter harsh and hypoxic environment in ischemic tissues, which leads to cell death and decreased therapeutic efficiency. On the other hand, the fate of stem cell viability and differentiation  is still an ambiguous issue in cell therapy regenerative medicine. To overcome this problem, Hypoxic/Ischemic preconditioning has been reported as a powerful tool with beneficial effects on cell survival. The reported master regulator in this process is a transcription factor known as HIF-1α. This study aimed to over-express HIF-1α in mesenchymal stem cells along with eGFP by using lenti viral vectors. Bisistronic expression of eGFP and HIF-1α provides the possibilities of tracking the transplanted cells and mimicking the hypoxic conditions for genetically modified stem cells for future animal model studies.  

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Most patients with liver diseases are in the waiting list of liver implantation for a long period of time because of the lack of enough donors. Liver differentiation potential of Mesenchymal Stem Cells (MSCs) is a new perspective in curing these patients. Tissue engineering improves hepatocyte differentiation by coating the culture surfaces with Glycosaminoglycans (GAGs) such as Heparan Sulfate (HS). Cell detachment and death during hepatogenic differentiation hamper the efficiency of cell therapy. This study aims to establish a matrix. mimicking the liver extracellular matrix, which supports the attachment and proliferation potential of MSCs, as well. Collagen was physically coated on polystyrene plates. Collagen-GAG matrix was constructed by covalently immoblizing the HS molecules on collagen by EDC. Cell attachment and proliferation were evaluated by direct cell-counting and MTT methods. GAG presence on collagen was verified by Safranin O staining. Comparisons showed that the highest attachment belonged to collagen, collagen-HS and polystyrene, respectively. Collagen matrix showed also the highest cell proliferation. Collagen-GAG provided more suitable matrix for cell proliferation compared to polystyrene. The results further showed that biomimicked collagen-GAG matrix supports superior attachment and viability for MSCs compared to polystyrene.

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Backgrounds: It is evident that the success of common cancer treatments is reduced due to limited drug access to tumor tissue, the drug toxicity intolerance in healthy cells, as well as the exposure of the immune system to the drug. Cancer stem cells are also a small population of tumor cells, which have different potentials for regeneration, proliferation, and differentiation and serve as a carcinogenic driving force. They are believed to play a key role in the onset, progression, drug resistance, recurrence of cancer, or metastasis. Although mesenchymal stem cells (MSC) have a slight ability to migrate toward the tumor, they could be considered as a cellular carrier for tumor targeting due to lack of recognition by the host immune system. Stem cells with their own ligands could effectively target cancer cells. One of the CD markers that exist on the surface of stem cells is CD44v6, which is considered as a homing receptor. Given that the expression level of stem cell markers is reduced during consecutive cultures in vitro environment; therefore, in the present study, stem cells were engineered using CD44 lentiviral vectors to more effectively improve the implantation and targeting of the colon cancer cell model.
Materials & Methods: In this study, the structure of the CD44 gene was designed in lentiviral vectors and transfected to the HEK293T cell line along with auxiliary plasmids PSPAX2 and PMDG2. The growth medium of virus-containing cells was collected at optimized intervals, and transduction into mice mesenchymal stem cells, injection into mice, and homing processes were traced.
Findings: Successful production of lentiviral vectors and proper expression of the corresponding factor after transduction were effective in improving the MSC homing in cancer cell.
Findings: According to these findings, it could be suggested that high expression of CD44v6 factor could be effective in improving the implantation process in cancer cells and targeting treatment.
 

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Clinical application of embryonic stem (ES) cells faces difficulties regarding tissue rejection as well as ethical limitations. One solution for these issues is to reprogram somatic cells by the injection of their nucleus into an enucleated oocyte or zygote. However, technical complications and ethical considerations have impeded the therapeutic implications of this technology. An approach which is most recently developed is in vitro induction of reprogramming in adult cells. This was first achieved by using four transcription factors, including Oct4, Sox2, c-Myc and Klf4. Subsequently, many ongoing efforts were performed for enhancing this method, also for making it compatible with clinical applications. However, there is still a long road ahead. In this paper we review strategies to reprogram somatic cells to embryonic state and discuss about the recent strategy and the relevant developments.

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Cancer stem cells are responsible for the formation the resistance to treatment, tumor relapse, and metastasis. miRNAs play an important role in the regulation of biological processes. Therefore, the purpose of this review is to candidate miRNAs that are involved in the regulation of all three properties including stemness, metastasis, and drug resistance and find their target genes and signaling pathways by using literature learning and data mining. The present systematic review is done to identify stemness-regulating miRNAs. By using CORMINE database, metastasis and drug resistance regulating miRNAs collected. Finally, we compared these three lists of miRNAs and found common miRNAs in these three properties. ONCO.IO database and KEGG pathway have been done to obtain the interaction between miRNA-miRNA target and cancer-related signaling pathway respectively. We collected 191 stemness-regulating miRNAs from 21 excluded studies. Based on CORMINE database, 161 miRNAs and 57 miRNAs had metastasis and stemness features respectively. We obtained 7 common miRNAs that 4 of them including has-miR-34a, has-miR-23a, has-miR-30a, has-miR-100 has a significant role for targeting signaling pathways involved in cancer and their most important targets regulate many processes of cells. These data suggest that three important properties can regulate by common miRNAs. Therefore, target these miRNAs or their targets can be helpful to stop tumor growth and metastasis and may be useful biomarkers for early detection of gastric cancer.

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Aims: In bone tissue engineering, the scaffold as a supportive structure, plays a vital role. Putting the scaffold in dynamic cell culture, such as perfusion bioreactor, makes the role of mechanical parameters such as shear stress and hydrodynamic pressure more important. On the other hand, these mechanical parameters are influenced by scaffold architecture. In this study, the effects of bone scaffold architecture on mechanical stimuli have been analyzed and their effects on the mesenchymal stem cell fate have been predicted.
Material & Methods: Using the tools of computer simulation, five bone scaffolds (Gyroid, high porous Gyroid, Diamond, IWP, and gradient architecture Gyroid) based on mathematical functions of minimal surfaces were designed and exposed in a simulated dynamic cell culture under the inlet velocities of 1, 10, 25, 50, and 100μm/s. Cell accumulation on the inner part of the scaffold was considered as an 8.5-micron layer. This layer was designed for Gyroid and IWP scaffolds.
Findings: Based on the results, Diamond scaffold showed the most efficient performance from the homogeneity of stresses point of view. In the presence of the cell layer, the von Mises stress was reported as 60 and 50 mPa on the Gyroid and IWP scaffolds, respectively which eases osteogenic differentiation.
Conclusion: In gradient architecture scaffolds under dynamic conditions, there is a gradient in shear stress that causes various signaling in different positions of theses scaffold and facilitates multi-differentiation of the cells on the same scaffold.

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Objective: The environmental exposure to Magnetic Fields (MFs) may interact with biological systems. MFs are generated from various sources such as power lines, electric appliances at homes and offices, electrified transportation systems including urban railway systems and diagnostic devices such as Magnetic Resonance Imaging (MRI). There are some scientific evidences that imply the exposure to MFs are hazardous to our health and increases the rate of some cancers like leukemia. The biological consequences of exposure to MFs have been investigated from a variety of endpoints. However, most studies have been performed in vitro and have examined effects on cellular processes and its malfunction; such studies can be used as evidence of effects in vivo. Materials and Methods: In this study Bone Marrow Stem Cells were grown in the absence and in the presence of a 15 mT Static Magnetic Field for 5 hours in order to determine any changes in cell cycle progression using the count of cells in different phases. The count of cells in a special phase of cell cycle indicates the length of that phase. The Static Magnetic Field was performed using a locally designed MF generator. Results: A significant increase in the number of cells in G0/G1 was observed in comparison with the controls. Also the number of cells in G0/G1 in the cells treated with Hydrogen-Peroxide, as an oxidative agent, was significantly increased in Static MF. Conclusion: Genetic material damages or mal-function of related proteins may cause these halts. Mfs have not enough energy to affect the biological molecules directly but the mechanism of free radical mediators is probable. These kinds of damages (direct or indirect) can permanently bring the cell cycle to a halt.

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Spermatogonial stem cells (SSCs) are unique with an important role in the transmission of genetic information to the next generation. Thus, they play an important role for the production of interspecies germ line chimeras. Therefore, the objective of this study was to produce chimera through the intraperitoneal transplantation of Caspian brown trout SSCs into newly-hatched rainbow trout. Spermatogonial cell were isolated from the testes of 8-month-old Caspian brown trout through enzymatic digestion. The spermatogonial cell suspension was enriched using differential plating technique to remove testicular somatic cells. After culturing for 48 h in L15 supplemented with 10% serum, suspended cells were collected and stained with the fluorescent membrane dye PKH26. The stained cells were intraperitoneally transplanted into triploid rainbow trout hatchlings. At 15 and 30 days after transplantation, the recipients were investigated under a fluorescent microscope. The gonads of recipients were dissected for molecular analysis at 180 days after transplantation. Transplanted spermatogonial cells migrated toward and incorporated into recipient genital ridges. The presence of the Caspian brown trout genetic material was confirmed by PCR in 41.4% of the rainbow trout testes. These results demonstrated for the first time that the interspecies spermatogonial transplantation was successful in rainbow trout and that the somatic microenvironment of the rainbow trout gonad can support the colonization and survival of intraperitoneally transplanted cells derived from a fish species belonging to a different genus. Therefore, the SSCs transplantation can be used as a tool for conservation of Caspian brown trout genetic resources.

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 Graphene-based nanomaterials are being investigated for their biocompatibility and bioactivity, as well as their ability to improve osteogenic differentiation. In this research, the base material, reduced graphene oxide (rGO) sheets, were decorated with hydroxyapatite and strontium (rGO / HAp-Sr) to induce osteogenic differentiation in adipose-derived mesenchymal stem cells. Different techniques were used to determine the properties of the nanocomposite such as diffraction analysis techniques (XRD) and transmission electron microscopy (to evaluate the size and morphology of HAp-Sr on rGO plates), FT-IR (to analyze the nanocomposite functional group), Raman spectroscopy (to investigate possible disorders in nanocomposite structure and number of layers), induced dual plasma emission spectroscopy (to assess atomic concentration of Ca and Sr), zeta potential(electrical potential of the nanocomposite) and MTT (nanocomposite cytotoxicity assessment) were used. The ossification potential of the synthesized nanocomposite was investigated and confirmed using the calcium deposition test in dipose-derived mesenchymal stem cells. According to the obtained results, osteogenic differentiation induction is possible using synthesized nanocomposites without the need for chemical inducers.
 

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Mechanical properties of living cells play an important role in helping to understand cell physiology and pathology. Evaluation of mechanical properties of cells may potentially lead to new mechanical diagnostic methods for some of these diseases. In this study, viscoelastic properties of the outer layer (cytoplasm and membrane) were extracted using standard linear solid model. Finite element modeling of the two cell layers is performed and the model is validated by experimental data. In the two-layer model, the effect of the radius of the nucleus and the location of the nucleus in the cell are investigated on the cell properties. By reducing the cytoplasmic radius ratio up to 43%, the whole cell properties follow the cytoplasmic properties and the effect of the nucleus can be neglected. The 50-second displacement change at a radial ratio of 0.53 increased to 4.5% compared to radial ratio of 1.58.  At a radial ratio of 0.43, a change in cell behavior was observed compared to the previous one, with a displacement change equals to 6.8% compared to radial ratio of 1.85 and a displacement reduction of 9.5% at a radial ratio of 0.53. The results demonstrate that the location of the nucleus and the ratio of the radius of the cytoplasm to the radius of the nucleus can effectively influence the viscoelastic properties and mechanical behavior of the cell.

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Objective: Average Age of population in the industrial countries has increased. Because of aging the percent of the diseases related to the oldness such as multiple myeloma have also increased. It has both common and unique symptoms and effects. The unique effects include wide bone reabsorption. It seems necessary to understand the structure of Bone Marrow Niche and the effects of Myeloma cells on adjacent hematopoietic Stem cells with a new approach. Materials and Methods: We have studied the differentiating effect induced by the Myeloma cells through co-culturing the Myeloma cells and hematopoietic stem cells, extracted out of cord blood. In this investigation we also cocultured myeloma cells with the monoblastic cell line (U937) in order to evaluate the effect of myeloma cells on monoblastic cells differentiation. Results: Our findings show that increased expression of myeloid and monocytoid markers in coculturing of myeloma cells and HSCs. Moreover following monoblastic and myeloid cells coculturing, we observed probably TRAP positive osteoclastic like cells. Conclusion: Our findings show that presence of myeloma cells in Bone Marrow play essential role in HSCs differentiation to monocytoid (osteoclastic) lineage.

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Objective: Cell vital function has correlation with mechanical loadings that cell experiences. Here, effects of in-vitro combined cyclic-static stretch on proliferation of human mesenchymal stem cell (HMSC) were evaluated. Materials and Methods: HMSCs were cultured on gelatin coated elastic membranes, and exposed to stretch loading. Four different regimes of cyclic, static, combined cyclic-static, and cyclic with a period of unloading were exerted on the elastic membrane. Duration of cyclic loading and static loading was 5 and 12 hours respectively. Results: The results illustrate that 10% cyclic stretch causes cell alignment but there were no significant proliferation differences between control and test group. Combined cyclic-static stretch reduced proliferation significantly while cyclic stretch with an unloading period increased cell proliferation significantly. At last, static stretch did not affect cell proliferation significantly. Conclusion: Cell stretching regimes and post-loading duration are effective factors on cell proliferation.

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Stem cells are characterized by their capacity for self-renewal and their ability to differentiate into specific cell types under the influence of their microenvironment. It is known that matrix chemistry controls stem cell differentiation. Single cell encapsulations of the Mesenchymal stem cells into a semi-permeable microgel, allows a greater control of the stem cell fate. In this study, a chip for single-cell encapsulation was designed and fabricated using microfluidic technology. By using microfluidic chip, human bone marrow mesenchymal stem cells (hBMSCs) are encapsulated inside alginate and alginate-poly-l lysine (PLL) microgels. The results of long-term viability of MSCs inside alginate-PLL microgels, shows a significant increase compared to alginate microgels. Mesenchymal stem cell proliferation in alginate-PLL microgels also increased significantly on days 14 and 21. It seems that PLL improves cell adhesion and function by creating a positively charged matrix. Microscopic studies indicate that the morphology of the cells inside the microgels is spherical. However, the average diameter and volume of cells in microgels containing PLL are smaller than others, which indicates more proliferation and space limitation inside the microgels. Therefore, single cell alginate-PLL microgels provide a suitable substrate in clinical studies for tissue engineering, organ transplantation and cell therapy.

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Evaluating the response of the stem cells to different mechanical stimulation is an important issue to obtain control over cell behavior in the culture environment. One of the effective parameters in the mechanoregulation of stem cells is the microstructure of scaffolds. Evaluating the effect of microstructure of scaffold in the lab environment is very complicated. Therefore, in this study, the effect of scaffold architecture on mechanical factors in the scaffold was investigated under oscillatory fluid flow by using numerical modeling. In this study, distribution of shear stress and fluid velocity in three types of scaffolds with spherical, cubical and regular hexagonal pores with length of 300, 350, 400, 450 and 500 micrometers were investigated by using computational fluid dynamics method. The results of the computational fluid dynamics model showed that the scaffold with spherical and cubic pores shape with length of 500 micrometers and scaffold with hexagonal pores with length of 450 micrometers experienced shear stress in the range of 0.1-10 mPa. This range of the shear stress is suitable for differentiation of the stem cell to bone cells. Moreover, the result of exerting oscillatory fluid flow to these scaffolds indicated that dead zones of the scaffold, where isn’t suitable for cell seeding, was decreased due to the access of fluid flow to the different area of scaffold. The results of this study can be used in a laboratory to achieve optimal stem cell culture to provide suitable environment culture for differentiation of stem cells toward the bone cell.