Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue engineering may offer patients new options when replacement or repair of an organ is needed. However, most tissues will require a microvascular network to supply oxygen and nutrients. One strategy for creating a microvascular network would be promotion of vasculogenesis in situ by seeding vascular progenitor cells within the biopolymeric construct. To pursue this strategy, we isolated CD34(+)/CD133(+) endothelial progenitor cells (EPC) from human umbilical cord blood and expanded the cells ex vivo as EPC-derived endothelial cells (EC). The EPC lost expression of the stem cell marker CD133 but continued to express the endothelial markers KDR/VEGF-R2, VE-cadherin, CD31, von Willebrand factor, and E-selectin. The cells were also shown to mediate calcium-dependent adhesion of HL-60 cells, a human promyelocytic leukemia cell line, providing evidence for a proinflammatory endothelial phenotype. The EPC-derived EC maintained this endothelial phenotype when expanded in roller bottles and subsequently seeded on polyglycolic acid-poly-l-lactic acid (PGA-PLLA) scaffolds, but microvessel formation was not observed. In contrast, EPC-derived EC seeded with human smooth muscle cells formed capillary-like structures throughout the scaffold (76.5 +/- 35 microvessels/mm(2)). These results indicate that 1) EPC-derived EC can be expanded in vitro and seeded on biodegradable scaffolds with preservation of endothelial phenotype and 2) EPC-derived EC seeded with human smooth muscle cells form microvessels on porous PGA-PLLA scaffolds. These properties indicate that EPC may be well suited for creating microvascular networks within tissue-engineered constructs.
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PMID:Tissue-engineered microvessels on three-dimensional biodegradable scaffolds using human endothelial progenitor cells. 1527 91

Recently, some studies have shown that nicotine increased neovascularization, which involves endothelial progenitor cells (EPCs). The effects of nicotine on EPCs are still unclear at present. Therefore, the authors investigated whether nicotine had influences on EPC number and activity. The EPCs were stimulated with nicotine (to make a series of final concentrations: 10(-12) mol/L, 10(-10) mol/L, 10(-8) mol/L, 10(-6) mol/L, 10(-4) mol/L) or vehicle control for the respective time points(12, 18, 24, 32, and 48 hours). The EPCs were characterized as adherent cells double positive for DiLDL uptake and lectin binding by direct fluorescent staining under a laser-scanning confocal microscope. They were further documented by demonstrating the expression of KDR, VEGFR-2, and AC133 with flow cytometry. The EPC proliferation, migration, and in vitro vasculogenesis activity were assayed with the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay; the modified Boyden chamber assay; and the in vitro vasculogenesis kit, respectively. The EPC adhesion assay was performed by replating those on fibronectin-coated dishes and then counting the adherent cells. As a result, nicotine dose dependently increased the EPC number and the proliferative, migratory, adhesive, and in vitro vasculogenesis capacity at nicotine concentrations of 10(-12) to 10(-8) mol/L. The peak effects on EPCs were observed at concentrations of nicotine 10(-8) mol/L, similar to those in the blood of smokers. In addition, nicotine (10(-8) mol/L) time dependently increased the EPC number and activity. However, cytotoxicity was seen at higher nicotine concentrations (> 10(-6) mol/L). In conclusion, nicotine had complex effects on EPCs: nicotine might induce the augmentation of EPCs with enhanced functional activity at relatively low concentrations. However, cytotoxicity was seen at higher nicotine concentrations.
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PMID:Effects of nicotine on the number and activity of circulating endothelial progenitor cells. 1528 92

Infusion of different hematopoietic stem cell populations and ex vivo expanded endothelial progenitor cells augments neovascularization of tissue after ischemia and contributes to reendothelialization after endothelial injury, thereby, providing a novel therapeutic option. However, controversy exists with respect to the identification and the origin of endothelial progenitor cells. Overall, there is consensus that endothelial progenitor cells can derive from the bone marrow and that CD133/VEGFR2 cells represent a population with endothelial progenitor capacity. However, increasing evidence suggests that there are additional bone marrow-derived cell populations (eg, myeloid cells, "side population" cells, and mesenchymal cells) and non-bone marrow-derived cells, which also can give rise to endothelial cells. The characterization of the different progenitor cell populations and their functional properties are discussed. Mobilization and endothelial progenitor cell-mediated neovascularization is critically regulated. Stimulatory (eg, statins and exercise) or inhibitory factors (risk factors for coronary artery disease) modulate progenitor cell levels and, thereby, affect the vascular repair capacity. Moreover, recruitment and incorporation of endothelial progenitor cells requires a coordinated sequence of multistep adhesive and signaling events including adhesion and migration (eg, by integrins), chemoattraction (eg, by SDF-1/CXCR4), and finally the differentiation to endothelial cells. This review summarizes the mechanisms regulating endothelial progenitor cell-mediated neovascularization and reendothelialization.
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PMID:Endothelial progenitor cells: characterization and role in vascular biology. 1532 44

Endothelial progenitor cells (EPCs) can differentiate from mononuclear cells (MNCs) of adult human peripheral blood, bone marrow, and cord blood during culture. Although MNCs are usually isolated by a Ficoll gradient centrifuge method, this method is time-consuming, and blood is easily contaminated. We developed a novel cell filtration device (StemQuickE, Asahi Kasei Medical, Oita, Tokyo, Japan) to isolate MNCs from human cord blood and examined whether functional EPCs could differentiate from MNCs isolated by this device. Recovery rates of MNCs, CD34(+) and CD133(+) progenitor cells, were significantly greater in the StemQuickE method than in the Ficoll method. During MNC culture, spindle-shaped attaching cells developed, and most of these cells incorporated DiI-acetylated low-density lipoprotein and showed positive binding to fluorescein isothiocyanate-lectin. Reverse transcription-polymerase chain reaction analysis revealed that attaching cells expressed various progenitor and endothelial lineage markers such as KDR, CD31, endothelial cell nitric oxide synthase, CD133, and LOX-1. Culture-expanded EPCs were isolated and labeled with a green fluorescent dye, PKH2-GL, and cocultured with human umbilical vein endothelial cells (HUVECs). EPCs formed angiogenesis-like networks together with HUVECs in 3D matrix gel. Finally, EPCs (3 x 10(5)) were implanted into ischemic hindlimb of nude rats (n = 3), and laser Doppler blood flowmetry (LDBF) revealed that the ratio of ischemic to normal limb LDBF was significantly greater in EPC-transplanted animals compared with controls receiving saline. In conclusion, the novel cell filtration device, StemQuickE, is a useful tool to isolate MNCs from human cord blood. Moreover, MNCs obtained by this filter system can give rise to functional EPCs.
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PMID:Derivation of functional endothelial progenitor cells from human umbilical cord blood mononuclear cells isolated by a novel cell filtration device. 1553 90

Angiogenesis governs the progression of multiple myeloma (MM). Circulating endothelial cells (CECs) contribute to angiogenesis and comprise mature ECs and endothelial progenitor cells (EPCs). The present study sought to characterize CECs and their relation to disease activity and therapeutic response in 31 consecutive patients with MM. CECs, identified as CD34(+)/CD146(+)/CD105(+)/CD11b(-) cells, were 6-fold higher in patients compared to controls and correlated positively with serum M protein and beta(2)-microglobulin. Circulating EPCs displayed late colony formation/outgrowth and capillary-like network formation on matrigel; these processes were inhibited after effective thalidomide treatment. Co-expression of vascular endothelial growth factor receptor-2 (KDR) and CD133 characterized EPCs in MM, and KDR mRNA elevations correlated with M protein levels. In vitro exposure of ECs to thalidomide or its derivative CC-5013 inhibited gene expression of the receptors for transforming growth factor-beta and thrombin. Thus, elevated levels of CECs and EPCs covary with disease activity and response to thalidomide, underscoring the angiogenic aspect of MM and suggesting that angioblastlike EPCs are a pathogenic biomarker and a rational treatment target in MM. The results also highlight the anti-angiogenic properties of thalidomide and CC-5013 and further elucidate possible mechanisms of their effectiveness against MM. (Blood. 2005;105:3286-3294).
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PMID:Circulating endothelial progenitor cells in multiple myeloma: implications and significance. 1561 73

The aim of this study was to investigate the effect of transmuscle laser revascularization (TMR) in combination with endothelial progenitor cell grafting on neovascularization of ischemic hindlimbs of nude rats. Mononuclear cells (MNCs) isolated from human umbilical cord blood (HUCB) by density gradient centrifugation were expanded in vitro. Spindle-shaped attaching (AT) cells and cord-like structures were developed from culture of MNCs. Acetylated low-density lipoprotein (Ac-LDL) incorporation by AT cells was performed. Phenotypic characterization was assessed by immunocytochemistry, and flow cytometry analysis. EPCs were labeled with 1, 1'-dioctadecyl-1 to 3,3, 3', 3'- tetramethyl-indocarbocyanine perchlorate (DiI) before being injected into the Nd:YAG laser channels or ischemic region. An acute ischemic limb model was created with the following four groups of nude rats by ligating the right external iliac artery: TMR + EPC group: rats with local transplantation of EPCs into laser channels; TMR group: those with transmuscular channels created without EPCs; EPC group: those with EPCs injected into the ischemic hindlimb; control group: an ischemic model without TMR or EPCs. All rats underwent femoral artery ultrasonic blood flow measurements of the ischemic and nonischemic limbs to obtain a flow ratio (femoral artery flow index [FAFI]: right femoral artery flow/left femoral artery flow) immediately after ligation of the artery (at baseline) and 28 days postoperation, and the ischemic limb muscle was sampled for histochemical and immunohistologic analysis. AT cells expressed AC 133 and endothelial cell (ECs) markers (KDR, CD34, CD31, and von Willebrand factor) and exhibited function similar to that of ECs as estimated by Ac-LDL incorporation. Flow cytometric analysis revealed that AT cells were positive for CD34 (62% +/- 7%) and AC133 (57.2% +/- 9.8%) at day 7 of culture. Twenty-eight days after the operation, the FAFI was significantly higher in the TMR+EPC group and EPC group than that in the control group. It was significantly higher in the TMR+EPC group, EPC group, and TMR group than that at their respective baselines. The FAFI in the control group was unchanged and no difference in FAFI was found between the TMR group and control group, and among the TMR+EPC, TMR, and EPC groups. TMR+EPC, TMR, and EPC treatment resulted in an increased number of capillaries in the treated regional area compared to the control group. Nd: YAG-laser transmuscle revascularization combined with the EPC grafting can significantly ameliorate perfusion and augment neovascularization in this ischemic hindlimb model of nude rats.
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PMID:Implantation of endothelial progenitor cells into laser-induced channels in rat ischemia hindlimb augments neovascularization. 1578 70

Mesenchymal stem cells (MSC) can be isolated from many sites adults and the fetus. Cells with osteoblastic, chondrogenic, leiomiogenic and stromogenic potentials have been obtained from the bovine artery wall, and we now show that MSC can be isolated also from the adult human vein wall. Cells detached from internal surface of the saphenous vein are cultured in vitro for 2-3 weeks and replated weekly. The culture forms a semi-confluent layer of spindle-shaped cells that are CD13(+), CD29(+), CD44(+), CD34(-), CD45(-), CD14(-), CD133(-), CD31(-), CD33(-), CD54(+), CD106(-), CD90(+), KDR(-), cadherin-5-, HLA class I(+) and HLA-DR- and differentiate in vitro into osteoblasts, chondrocytes and adipocytes. Gene expression, when compared with seven other normal tissues, shows strong similarity with MSC obtained from other sources. Three genes more expressed in saphenous MSC than in the other two MSC are related to angiogenesis, and the expression of two of them is shared by endothelial cells. These results demonstrate that the human vein wall contains mesenchymal cells with morphologic features, immunophenotypic markers, gene expression profile and differentiation potential that are similar to MSC obtained from the bone marrow and from the umbilical vein.
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PMID:Mesenchymal stem cells can be obtained from the human saphena vein. 1601 99

Human pluripotent embryonic stem cells (hESC) have great promise for research into human developmental biology and the development of cell therapies for the treatment of diseases. To meet the increased demand for characterized hESC lines, we present the derivation and characterization of five hESC lines on mouse embryonic fibroblast cells. Our stem cell lines are characterized by morphology, long-term expansion, and expression profiles of a number of specific markers, including TRA-1-60, TRA-1-81, alkaline phosphatase, connexin 43, OCT-4, NANOG, CXCR4, NODAL, LEFTY2, THY-1, TDGF1, PAX6, FOXD3, SOX2, EPHA2, FGF4, TAL1, AC133 and REX-1. The pluripotency of the cell line was confirmed by spontaneous differentiation under in vitro conditions. Whereas all of the cell lines expressed all the characteristics of undifferentiated pluripotent hESC, two of the cell lines carried a triploid karyotype.
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PMID:Generation of new human embryonic stem cell lines with diploid and triploid karyotypes. 1651 55

Endothelial progenitor cells (EPCs) contribute to blood vessel formation in ischemic and tumorous tissues, but comprise only a small population in circulation. We attempted to immortalize putative EPCs from human cord blood. Human CD34+ cord blood cells were cultured in the presence of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF), and transfected with a retroviral vector encoding the simian virus 40 large T (SV40T) antigen. This resulted in the immortalization of cord blood cells, leading to the establishment of several cell lines. One of these lines, HYCEC-1, exhibited a phenotype characteristic of the endothelial lineage, including expression of von Willebrand factor and VEGF receptor-2 (VEGFR-2/KDR/Flk-1) and uptake of acetylated-low density lipoprotein. Flow cytometric analysis revealed that HYCEC-1 cells were strongly positive for CD31 and CD146, moderately positive for CD144, weakly positive for CD133 and CD34, and negative for CD14 and CD45. HYCEC-1 cells formed capillary-like structures on basement matrix gel in vitro. Upon transplantation into the ischemic hind limb of nude rats, HYCEC-1 cells efficiently participated in neovascularization and augmented blood flow. The immortalized HYCEC-1 cells are suggested to be a class of EPCs that can efficiently participate in postnatal neovasculogenesis in the ischemic hind limb, and may also be a useful tool for studying tumor vessel formation.
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PMID:Postnatal neovascularization by endothelial progenitor cells immortalized with the simian virus 40T antigen gene. 1652 29

The number and properties of endothelial progenitor cells (EPC) in disease states is of considerable interest due to the importance attributed to this distinct cell population. However, there has been no study comparing each of the methods employed in the same sampled individuals. Herein, we performed an analysis of several methods used for circulating EPC assessment and correlated them with humoral factors known to influence their numbers. Thirty-eight individuals (mean age of 34 +/- 9 years) were tested. Peripheral blood mononuclear cells were obtained and stained for FACS analysis with antibodies to CD34, CD45, CD133, and KDR and the remaining cells grown under endothelial cell conditions for assessment of colony-forming unit (CFU) numbers and adhesive properties. Levels of circulating vascular endothelial growth factor (VEGF), erythropoietin (EPO), and C-reactive protein (CRP) were determined and correlated with each of the EPC markers. CFU numbers did not correlate with CD34/KDR or CD34/CD133/KDR and negatively correlated with CD34/ CD133 numbers. CD34/KDR numbers correlated with CD34/CD133/KDR, but not with CD34/ CD133. Only CD34/KDR and CD34/CD133/KDR correlated with VEGF serum levels. The number of EPC adhering to fibronectin and endothelial cells correlated with CFU numbers and not with either of the EPC membrane markers. Current methods for quantitatively assessing numbers of circulating EPC are not correlated. VEGF serum levels are associated only with CD34/KDR and CD34/ CD133/KDR, whereas CFU numbers correlate with EPC functional properties. These findings may suggest that CD34/KDR is more appropriate for the definition of circulating EPC, whereas CFU numbers are more likely to reflect their ability to proliferate.
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PMID:Comparative analysis of methods for assessment of circulating endothelial progenitor cells. 1654 91


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