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Several studies have shown the presence of fibroblast-like cells in the stromal fraction of different tissues with a high proliferative and differentiation potential. Platelet alpha granules contain growth factors released into the environment during activation. The effects of different supplements for culture medium (human serum, bovine serum and platelet lysate) on cultured human fibroblast-like cells from bone marrow, adipose tissue, trabecular bone and dental pulp have been compared. Expression of typical stromal and hematopoietic markers was analyzed and proliferative rates were determined. Flow cytofluorometry showed a homogenous pattern in serial-passaged cells, with a high level of stromal cell-associated markers (CD13, CD90, CD105). The presence of platelet lysate in culture media increased the number of cell generations obtained regardless of cell source. This effect was serum-dependent. Cell-based therapies can benefit by the use of products from human origin for "ex vivo" expansion of multipotent cells.

1The novel cation channel blocker, LOE 908, was tested for its effects on Ca2+ entry and membrane currents activated by depletion of intracellular Ca2+ stores in human endothelial cells.2 LOE 908 inhibited store-operated Ca2+ entry induced by direct depletion of Ca2+ stores with 100 nM thapsigargin or 100 nM ionomycin with an EC50 of 2 giM and 4 giM, respectively. 3 LOE 908 did not affect thapsigargin-or ionomycin-induced Ca2+ release from intracellular stores up to concentrations of 3 gIM. 4 LOE 908 reversibly suppressed thapsigargin-as well as ionomycin-induced whole-cell membrane currents.5 The LOE 908-sensitive membrane conductance corresponded to a cation permeability of 5.5 and 6.9 fold selectivity for Ca2+ over K+ in the presence of thapsigargin and ionomycin, respectively. 6 Our results suggest that the isoquinoline, LOE 908 is a novel, potent inhibitor of the store-operated (capacitive) Ca2+ entry pathway in endothelial cells.

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The tolerogenic immunophenotype and diminished functionality of CB DCs can be important to create a microenvironment where Treg develop, that in turn may be relevant to observed lower incidence of chronic GVHD after CB transplantation.

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The stromal-vascular fraction (SVF) of human adipose tissue contains, among other cell types, mesenchymal stem cells and precursors of adipocyte and endothelial cells. Here we show that, in addition, the nonhematopoietic fraction of the SVF has hematopoietic activity, since all types of hematopoietic colony-forming units (CFUs) developed when cultured in methylcellulose-based medium. This hematopoietic activity was restricted to the CD45 ؊ CD105 ؉ cell subset, well correlated with KDR ؉ cell content, and increased after culture with a combination of early-acting hematopoietic cytokines. Most of the CD45 ؊ KDR ؉ CD105 ؉ cells were nonadherent and did not express CD31, and this subset included both CD34؊ and CD34 ؉ cells. Moreover, these nonadherent cells migrated in response to KDR gradient, and when they were cultured in the presence of both hematopoietic and endothelial growth factors, a wave of CFUs was followed by a wave of mixed colonies comprising adherent elongated and nonadherent round hematopoietic cells. These mixed hematopoietic-endothelial (Hem-End) colonies were able to generate secondary Hem-End colonies and exhibited both hematopoietic and endothelial activity, as demonstrated by in vitro functional assays. These findings demonstrate for the first time the existence of primitive mesodermal progenitors within the SVF of human adipose tissue that exhibit in vitro hematopoietic and hemangioblastic activities, susceptible to being used in cell therapy and basic cell research.

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