Mobilization Of Mesenchymal Stem Cells Research Articles

Mobilization of Mesenchymal Stem Cells by Granulocyte Colony-stimulating Factor in Rats with Acute Myocardial Infarction

Intravenous delivery of mesenchymal stem cells (MSCs), a noninvasive strategy for myocardial repair after acute myocardial infarction (MI), is limited by the low percentage of MSCs migration to the heart. The purpose of this study was to test whether granulocyte colony-stimulating factor (G-CSF) would enhance the colonization of intravenously infused MSCs in damaged heart in a rat model of acute MI. After induction of anterior MI, Sprague-Dawley rats were randomized to receive: (1) saline (n=9); (2) MSCs (n=15); and (3) MSCs plus G-CSF (50 microg/kg/day for 5 consecutive days, n=13). Flow cytometry revealed that G-CSF slightly increased surface CXCR4 expression on MSCs in vitro. After completion of G-CSF administration, MSCs showed a significantly lower colonization in bone marrow and a trend toward higher localization in the infarcted myocardium. At 3 months, vessel density in the infarct region of heart was significantly increased in MSCs group and trended to increase in MSCs+G-CSF group. However, echocardiographic and hemodynamic parameters, including left ventricular (LV) end-diastolic diameters, ejection fraction, and +/-dP/dtmax, were not statistically different. Morphological analysis showed that infarct size and collagen content were similar in the three groups. Immunohistochemistry revealed that the combined therapy accelerated endothelial recovery of the blood vessels in the ischemic myocardium. However, myocardial regeneration resulting from MSCs differentiation was not observed. G-CSF enhanced the migration of systemically delivered MSCs from bone marrow to infarcted heart. However, the beneficial effect of this kind of migration is limited, as cardiac function did not improve.

Autologous synovial fluid enhances migration of mesenchymal stem cells from synovium of osteoarthritis patients in tissue culture system

Synovial fluid from osteoarthritic knee contains mesenchymal stem cells (MSCs). One of the possible reservoirs of MSCs in synovial fluid is synovial tissue, and synovial fluid may induce mobilization of MSCs into synovial fluid in osteoarthritis patients. Here, we investigated whether synovial fluid expanded synovial MSCs in a tissue culture system. Human synovium and synovial fluid were obtained from osteoarthritis patients during total knee arthroplasties. In the tissue culture system, autologous synovial fluid expanded synovial cells statistically higher than alpha MEM + FBS, and the addition of TGF beta 3 to alpha MEM + FBS increased expansion to a similar level in all 11 donors. The addition of decorin or anti-TGFbeta neutralizing antibody to synovial fluid partially inhibited synovial cell expansion. In cell culture assay, synovial fluid proliferated synovial cells fewer than alpha MEM + FBS. The expanded synovial cells in synovial fluid retained multipotentiality and showed surface markers similar to those of MSCs. We demonstrated that autologous synovial fluid enhanced expansion of MSCs in tissue culture of synovium from osteoarthritis patients by promoting cell migration. This effect was partially affected by TGFbeta.

Bone Marrow–Derived Mesenchymal Cell Mobilization by Granulocyte-Colony Stimulating Factor After Acute Myocardial Infarction

Granulocyte-colony stimulating factor (G-CSF) after myocardial infarction does not affect systolic function when compared with placebo. In contrast, intracoronary infusion of bone marrow cells appears to improve ejection fraction. We aimed to evaluate the G-CSF mobilization of subsets of stem cells. We included 78 patients (62 men; 56+/-8 years) with ST-elevation myocardial infarction treated with primary percutaneous intervention <12 hours after symptom onset. Patients were randomized to double-blind G-CSF (10 microg/kg/d) or placebo. Over 7 days, the myocardium was exposed to 25x10(9) G-CSF mobilized CD34+ cells, compared with 3x10(9) cells in placebo patients (P<0.001); and to 4.9x10(11) mesenchymal stem cells, compared with 2.0x10(11) in the placebo group (P<0.001). The fraction of CD34+ cells/leukocyte increased during G-CSF treatment (from 0.3+/-0.2 to 1.1+/-0.9 x10(-3), P<0.001 when compared with placebo), whereas the fraction of putative mesenchymal stem cells/leukocyte decreased (from 22+/-17 to 14+/-11 x10(-3), P=0.01 when compared with placebo). An inverse association between number of circulating mesenchymal stem cells and change in ejection fraction was found (regression coefficient -6.8, P=0.004), however none of the mesenchymal cell subtypes analyzed, were independent predictors of systolic recovery. The dissociated pattern for circulating CD34+ and mesenchymal stem cells could be attributable to reduced mesenchymal stem cell mobilization from the bone marrow by G-CSF, or increased homing of mesenchymal stem cells to the infarcted myocardium. The inverse association between circulating mesenchymal stem cells and systolic recovery may be of clinical importance and should be explored further.

Mechanism of mobilization of mesenchymal stem cell under the effect of granulocyte colony-stimulating factor

We studied the role of cell components and extracellular matrix of the microenvironment in the mechanisms of mobilization of mesenchymal bone marrow stem cells under the effect of granulocyte colony-stimulating factor in vitro and in vivo on CBA/CaLac mice. It was found that the mechanisms underlying the dissociation effect of granulocyte colony-stimulating factor do not include its direct effect on the interaction of precursor cells with fibronectin. The major role in this process is played by changes in functional state of stromal precursors and cell component of the microenvironment induced by granulocytic colony-stimulating factor and mediated by regulatory systems of the microorganism.

P110 Mobilization of mesenchymal stem cells varies with bone marrow stimulation techniques and affects the repair of articular cartilage defect

P110 Mobilization of mesenchymal stem cells varies with bone marrow stimulation techniques and affects the repair of articular cartilage defect

Creation of experimental models and study of the regeneratory potential of stem cells on these models

Mobilization of mesenchymal stem cells and their more mature descendants, their differentiation into tissue-specific precursors, and the possibility of pharmacological stimulation of these processes were studied on models of some prevalent diseases. It was found that the development of any pathological process was associated with more or less pronounced activation of primitive and more differentiated mesenchymal precursors in the bone marrow, their mobilization into the peripheral blood, and increase in the content of regional precursors in organs exposed to pathogenic factors. Additional stimulation of stem cells with granulocytic colony-stimulating factor usually led to earlier or more pronounced increase in the content of mesenchymal progenitors in the bone marrow and peripheral blood. The content of tissue-specific and then fibroblast precursors in the regenerating organs also increased. This was paralleled by a decrease in the volume of developing connective tissue and degree of infiltration in these organs, while the percentage of tissue-specific structures increased.

Mobilization of bone marrow-derived mesenchymal stem cells into the injured tissues after intraarticular injection and their contribution to tissue regeneration

The purpose of present study was to evaluate active mobilization effect of mesenchymal stem cells (MSCs) into injured tissues after intraarticular injection of MSCs, and to evaluate their contribution to tissue regeneration. MSCs, which were obtained from green fluorescent protein (GFP) transgenic Sprague-Dawley (SD) rat and cultivated, were injected into normal SD rats in which multiple tissues had been injured including anterior cruciate ligament (ACL), medial meniscus, and articular cartilage of the femoral condyles. At 4 weeks after injection of MSCs, fluorescent microscopic observation, immunohistochemical or histological examinations were performed to evaluate mobilization of MSCs into injured tissue and their contribution to tissue regeneration. In the group of 1 x 10(6) MSCs injection, GFP positive cells could mobilize into the injured ACL alone in all 8 knees. In the group of 1 x 10(7) MSCs injection, GFP positive cells were observed in the injured site of ACL in all 8 knees and in the injured site of medial meniscus and cartilage of femoral condyles in 6 of 8 knees. More interestingly, extracellular matrix stained by toluidine blue was present around GFP positive cells in the injured femoral condyles cartilage and medial meniscus, indicating tissue regeneration. Intraarticularly injected MSCs could mobilize into the injured tissues, and probably contributed to tissue regeneration. This study demonstrated the possibility of intraarticular injection of MSCs for the treatment of intraarticular tissue injuries including ACL, meniscus, or cartilage. If this treatment option is established, it can be minimally invasive compared to conventional surgeries for these tissues.

Mesenchymal stem cells: unknown mechanisms of differentiation

Mesenchymal stem cells: unknown mechanisms of differentiation

SDF-1-CXCR4 and HGF-c-met Axes Regulate Mobilization/Recruitment to Injured Tissue of Human Mesenchymal Stem Cells.

Human mesenchymal stem cells (MSC) have been shown to egress from the bone marrow (BM), circulate in peripheral blood (PB) and differentiate into many cell types, making them attractive as a potential therapeutic tool for organ/tissue regeneration. However the signals required for their mobilization into PB and their recruitment into injured sites are not fully understood. We previously reported that stromal-derived factor (SDF)-1 and hepatocyte growth factor (HGF) are upregulated at sites of tissue damage (Cancer Research 2003; 63:7926; Leukemia 2004; 18:29) and in this study we examined whether these factors mediate the migration of MSC. We investigated (i) the expression in MSC of CXCR4 and c-met, the cognate receptors of SDF-1 and HGF, (ii) whether they are functional after early and late passages (using a chemotaxis assay across fibronectin and the reconstituted basement membrane Matrigel), and (iii) whether MSC express matrix metalloproteinases (MMPs) known to facilitate mobilization and homing of stem cells. MSC were derived from human bone marrow (BM) or cord blood (CB) and maintained for up to 18 passages (in IMDM and 10–20% FCS) with monitoring of markers for cardiac (Nkx2.5/Csx, GATA-4 and MEF2-C), skeletal muscle (Myo-D and myogenin) and endothelial cells (VE-cadherin and VEGFR-2). We found that (i) CB and BM MSC strongly express CXCR4 and c-met transcripts for up to 15 passages, (ii) these receptors are functional as the MSC cells were chemotactic and chemoinvasive (across Matrigel) towards gradients of SDF-1 (100 ng/mL) or HGF (40 ng/mL), and (iii) CB and BM MSC express MMP-2 mRNA and secrete both latent and active forms of MMP-2. Moreover, we found that CB and BM MSC expressed mRNA for all three cardiac markers and the endothelial marker VE-cadherin, indicating their potential for heart regeneration. In conclusion, these results indicate that the SDF-1-CXCR4 and HGF-c-met axes are important signaling pathways in MSC mobilization and their trafficking in PB, and could be involved in recruitment of MSC to damaged tissues (e.g., myocardium).