جستجوی مقالات مرتبط با کلیدواژه "homing" در نشریات گروه "پزشکی"

Nowadays, transplantation of bone marrow-derived Mesenchymal Stromal Cells (BMSCs) is currently an important alternative therapy for patient’s type 1 diabetes mellitus. But a number of critical obstacles lie ahead of this new strategy including reducing stem cell homing to the damaged tissue due to oxidative stress. The purpose of the present study was to investigate whether preconditioning of BMSCs with SDF-1 could enhance their homing to the pancreas and promote regeneration of the pancreatic β cells after being intravenously injected. Mice BMSCs were isolated and expanded. Cell proliferation was assayed by MTT Assay. Preconditioning was performed with 10 ng/ml SDF-1α for 24 hr. Male NMRI mice were injected with high-dose STZ (150 mg/kg). The preconditioned or unpreconditioned BMSCs at a dose of 1×106 cells were infused via the tail vein. Blood and pancreatic tissue samples were taken from all mice for flow cytometry, biochemical and histological studies. Proliferation and homing of BMSCs to the pancreas were significantly increased in the BMSCs with SDF-1α preconditioning. Differentiation of transplanted BMSCs, were significantly increased in preconditioning group. Although BMSCs without SDF-1 preconditioning exhibited remarkable recovery of pancreatic islets structure but this recovery were significantly increased in the BMSCs with SDF-1α preconditioning. Our results showed the effectiveness of SDF-1αpreconditioning in BMSCs transplantation of STZ induced diabetes mice which might be achieved through improvement of BMSCs homing into the injured pancreas.

Hematopoietic stem and progenitor cells (HSPCs) are non-stop travelers throughout body in both time and space. Understanding the mechanism of HSPCs homing and mobilization is important to enhance the efficacy at bone marrow transplantation and cellular therapy. Mobilized HSPCs has largely replaced than the use of bone marrow as a source of stem cells for both allogeneic and autologous stem cell transplantation. This review describes the specific factors which play a key role in homing and mobilization of HSPCs, includes SDF-1 and its receptor CXCR4, proteases (MMPs and CPM). Moreover, chemokines inducing rapid HPSCs mobilization would be discussed. In this article we showed that many factors such as adhesion molecules and SDF-1/CXCR4 have critical roles in homing hematopoietic stem cells and G.CSF, MMPs, adhesion molecules and ROS involvement in mobilization of stem cells. According to above, we can be rich the peripheral blood of HSPCS using of this factors and antagonist for this receptors on the osteoblastic cells or/and HSPCs to bone marrow transplant.

The limited homing potential of bone-marrow-derived mesenchymal stem cells (BM-MSC) is the key obstacle in MSC-based therapy. It is believed that chemokines and chemokine receptor interactions play key roles in cellular processes associated with migration. Meanwhile, MSCs express a low level of distinct chemokine receptors and they even lose these receptors on their surface after a few passages which influence their therapeutic applications negatively. This study investigated whether treatment of BM-MSCs with hypoxia-mimicking agents would increase expression of some chemokine receptors and cell migration. BM-MSCs were treated at passage 2 for our gene expression profiling. All qPCR experiments were performed by SYBR Green method in CFX-96 Bio-Rad Real-Time PCR. The Boyden chamber assay was utilized to investigate BM-MSC homing. Possible approaches to increasing the expression level of chemokine receptors by different hypoxia-mimicking agents such as valproic acid (VPA), CoCl2, and desferrioxamine (DFX) are described. Results show DFX efficiently up-regulate the CXCR7 and CXCR4 gene expression while VPA increase only the CXCR7 gene expression and no significant change in expression level of CXCR4 and the CXCR7 gene was detectable by CoCl2 treatment. Chemotaxis assay results show that pre-treatment with DFX, VPA, and Cocl2 enhances significantly the migration ability of BM-MSCs compared with the untreated control group and DFX treatment accelerates MSCs homing significantly with a higher rate than VPA and Cocl2 treatments. Our data supports the notion that pretreatment of MSC with VPA and DFX improves the efficiency of MSC therapy by triggering homing regulatory signaling pathways.

Bone marrow (BM) is one of the major hematopoietic organs in postnatal life that consists of a heterogeneous population of stem cells which have been previously described. Recently, a rare population of stem cells that are called very small embryonic-like (VSEL) stem cells has been found in the BM. These cells express several developmental markers of pluripotent stem cells and can be mobilized into peripheral blood (PB) in response to tissue injury. In this study we have attempted to investigate the ability of these cells to migrate toward an injured spinal cord after transplantation through the tail vein in a rat model. In this experimental study, VSELs were isolated from total BM cells using a fluorescent activated cell sorting (FACS) system and sca1 and stage specific embryonic antigen (SSEA-1) antibodies. After isolation, VSELs were cultured for 7 days on C2C12 as the feeder layer. Then, VSELs were labeled with 1,1´-dioctadecyl-3,3,3´, ´ tetramethylindocarbocyanine perchlorate (DiI) and transplanted into the rat spinal cord injury (SCI) model via the tail vein. Finally, we sought to determine the presence of VSELs in the lesion site. We isolated a high number of VSELs from the BM. After cultivation, the VSELs colonies were positive for SSEA-1, Oct4 and Sca1. At one month after transplantation, real-time polymerase chain reaction analysis confirmed a significantly increased expression level of Oct4 and SSEA-1 positive cells at the injury site. VSELs have the capability to migrate and localize in an injured spinal cord after transplantation.