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ABSTRACT: Inadequate blood supply to tissues is a leading cause of morbidity and mortality today. Ischemic symptoms caused by obstruction of arterioles and capillaries are currently not treatable by vessel replacement or dilatation procedures. Therapeutic angiogenesis, the treatment of tissue ischemia by promoting the proliferation of new blood vessels, has recently emerged as one of the most promising therapies. Neovascularization is most often attempted by introduction of angiogenic cells from different sources. Emerging evidence suggests that adipose tissue (AT) is an excellent reservoir of autologous cells with angiogenic potential. AT yields two cell populations of importance for neovascularization: AT-derived mesenchymal stromal cells, which likely act predominantly as pericytes, and AT-derived endothelial cells (ECs). In this concise review we discuss different physiological aspects of neovascularization, briefly present cells isolated from the blood and bone marrow with EC properties, and then discuss isolation and cell culture strategies, phenotype, functional capabilities, and possible therapeutic applications of angiogenic cells obtained from AT.
Stem cells translational medicine. 09/2012; 1(9):658-67.
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ABSTRACT: In vitro generation of large numbers of autologous hematopoietic stem cells would be extremely useful for clinical applications. Adipose tissue derived mesenchymal stem cells (AT-MSC) are an easily available autologous source for cell therapy applications. Like hematopoietic cells, MSC are of mesodermal origin. The Cdx-Hox pathway is an important genetic program for hematopoiesis, where Cdx4 is a key upstream regulator of the Hox family. We introduced ectopic CDX4 gene in an attempt to reprogram AT-MSC to differentiate along the hematopoietic lineage. To further promote hematopoietic reprogramming, we cultured the transduced cells in cocktails of hematopoietic cytokines, growth factors or epigenetic modifiers. However, despite strong expression of CDX4 at the mRNA and protein levels, neither downstream HOX genes, other genes of importance for hematopoietic development or functional colony forming assays showed any evidence of hematopoietic reprogramming. Thus, despite the close developmental association between these cell types, the introduction of one single master switch transcription factor was not sufficient to promote hematopoietic reprogramming in AT-MSC.
Stem cell research 05/2012; 9(2):135-42. · 3.39 Impact Factor
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ABSTRACT: Endothelial cells (ECs) are involved in the process of angiogenesis, the outgrowth of new vessels from preexisting blood vessels. If available in sufficiently large numbers, ECs could be used therapeutically to establish blood flow through in vitro engineered tissues and tissues suffering from severe ischemia. Adipose tissue (AT) is an easily available source of large number of autologous ECs. Here we describe the isolation, in vitro expansion, and characterization of human AT derived ECs (AT-ECs). AT-ECs proliferated rapidly through 15-20 population doublings. The cultured cells showed cobblestone morphology and expressed EC markers including CD31, CD144, eNOS, CD309, CD105, von Willebrand factor, CD146, CD54, and CD102. They bound Ulex europaeus agglutinin I lectin and took up DiI-Ac-LDL. The AT-ECs formed capillary-like tubes in Matrigel in vitro and formed functional blood vessels in Matrigel following subcutaneous injection into immunodeficient mice. In conclusion, AT-ECs reach clinically significant cell numbers after few population doublings and are easily accessible from autologous AT, which also contains mesenchymal stem cells/pericytes. Thus, AT yields two cell populations that may be used together in the treatment of tissue ischemia and in clinical applications of tissue engineering.
Cell Transplantation 06/2011; 21(1):235-50. · 5.13 Impact Factor
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ABSTRACT: Human mesenchymal stem cells (MSC) are popular candidates for tissue engineering. MSC are defined by their properties in two-dimensional (2D) culture systems. Cells in 2D are known to differ from their in vivo counterparts in cell shape, proliferation, and gene expression. Little is so far known about the phenotype and gene expression of cells in three-dimensional (3D) culture systems. To begin to unravel the impact of 3D versus 2D culture conditions on MSC, we have established MSC from adipose tissue and bone marrow in 3D cultures in alginate beads covalently modified with the tripeptide arginine-glycine-aspartic acid (RGD), the integrin-binding motif found in several molecules within the extracellular matrix. The MSC changed from their fibroblastoid shape (2D) to a small, compact shape when embedded in RGD alginate (3D). High viability was maintained throughout the experiment. The MSC retained expression of integrins known to bind RGD, and practically ceased to proliferate. Microarray analysis revealed that the gene expression in cells in RGD alginate was different both from the cells cultured in 2D and from prospectively isolated, uncultured MSC, but more similar to 2D cells. As alginate may be entirely dissolved, leaving the cells as single cell suspensions for various analyses, this represents a useful model for the study of cells in 3D cultures.
Tissue Engineering Part A 01/2009; 15(7):1763-73. · 4.64 Impact Factor
