Functional and phenotypic alteration of intrasplenic lymphocytes affected by mesenchymal stem cells in a murine allosplenocyte transfusion model.

Previous data have demonstrated that mesenchymal stem cells (MSCs) can exert immunomodulatory activity in vitro, in which of the process nearly all kinds of immune cell subsets are involved. However, there is still a paucity of information about whether and why MSCs inhibit the ongoing immune responses in vivo. Working in a murine splenocyte transfusion model across the major histocompatibility barrier (C57BL/6 -BALB/c, H2b --> H2d), we have found that MSC coinfusion prolongs the mean survival time (MST) of the recipient mice in a dose-dependent manner and reduces graft-versus-host-associated histopathology in comparison to the allosplenocyte transfusion controls.

Functional and Phenotypic Alteration of Intrasplenic Lymphocytes Affected by Mesenchymal Stem Cells in a Murine Allosplenocyte Transfusion Model.

Previous data have demonstrated that mesenchymal stem cells (MSCs) can exert immunomodulatory activity in vitro, in which of the process nearly all kinds of immune cell subsets are involved. However, there is still a paucity of information about whether and why MSCs inhibit the ongoing immune responses in vivo. Working in a murine splenocyte transfusion model across the major histocompatibility barrier (C57BL/6 → BALB/c, H2b → H2d), we have found that MSC coinfusion prolongs the mean survival time (MST) of the recipient mice in a dose-dependent manner and reduces graft-versus-host-associated histopathology in comparison to the allosplenocyte transfusion controls.

Mesenchymal stem cells derived from human placenta suppress allogeneic umbilical cord blood lymphocyte proliferation.

Human placenta-derived mononuclear cells (MNC) were isolated by a Percoll density gradient and cultured in mesenchymal stem cell (MSC) maintenance medium. The homogenous layer of adherent cells exhibited a typical fibroblast-like morphology, a large expansive potential, and cell cycle characteristics including a subset of quiescent cells. In vitro differentiation assays showed the tripotential differentiation capacity of these cells toward adipogenic, osteogenic and chondrogenic lineages.

[Osteoblasts derived from mesenchymal stem cells harbor immunoregulatory effect].

In an attempt to study the immunoregulatory effect of osteoblasts derived from mesenchymal stem cells (MSC), MSC was induced to differentiate into osteoblasts for one week. The growth pattern and the phenotype were evaluated by MTT and flow cytometry respectively. The immunoregulatory effect was tested by the inhibitory effect on T cell proliferation.

Comparison of mesenchymal stem cells from human placenta and bone marrow.

Background: Nowadays bone marrow represents the main source of mesenchymal stem cells (MSCs). We identified a new population of MSCs derived from human placenta and compared its biological characterization with bone marrow derived MSCs.

Methods: Mononucleated cells (MNC) were isolated from the human placenta tissue perfusate by density gradient fractionation.

[Human placenta derived adherent cells support in vitro expansion of umbilical cord blood CD34+ cells].

The objective of this study was to elucidate the effect of human placenta adherent cells (hPDAC) on expansion of human umbilical cord blood CD34(+) cells in vitro. hPDAC was isolated and characterized in human placenta tissue by using enzyme-digesting method and flow cytometry. A co-culture system was established with hPDAC and cord blood CD34(+) cells.

Isolation of mouse marrow mesenchymal progenitors by a novel and reliable method.

Bone marrow contains a population of rare progenitor cells capable of differentiating into osteoblasts, chondrocytes, adipocytes, myoblasts, and hematopoiesis-supporting stromal cells. These cells, referred to as mesenchymal progenitor cells (MPCs), can be purified and culture-expanded from animals and humans. Using bone-marrow-conditioned medium combined with basic fibroblast growth factor, we cultured a relatively homogeneous population of MPCs from murine bone marrow, which uniformly expressed stem cell antigen-1, CD29, CD44, c-kit, and CD105, while being negative for expression of CD45, CD31, and CD34.

Current basic research of hematopoietic stem cells in China and comments on stem cell plasticity.

The basic studies selected were mainly published since 1998 and related to stem cell biology and engineering and particularly the efforts for developing new sources of hematopoietic stem/progenitor cells ex vivo. Hematopoietic cells and lymphocytes can be developed by induced differentiation in a appropriate way of culture, originating in the embryo- or adult-derived stem cells or tissue-committed stem cells which still exist in the tissue of adults. The most primitive multipotential embryonic stem cell from embryo or adult tissue has the plasticity to differentiate into every kind of progenies, the committed tissue-specific stem cell, by different proper ways of induction in vitro.

[Construction of Expression Vector for Human CD40-Ig Fusion Protein and Its Expression in COS-7 Cells].

CD40/CD40L, besides B7/CD28, is an alternative important costimulation signal transduction pathway. It plays a pivotal role in T cell activation. Moreover, it may play a critical role at many levels of sensitization and effector phases of allograft rejection.

[Challenges to Hematopoietic Stem Cell Research Today].

More works documented recently indicated that human CD34(-) cells exist and are likely to be the precursors of the CD34(+) cells. Anyhow, the CD34(+) enriched populations have already been proved to show long-term reconstitution of hematopoiesis in animals and patients worldwidely. It still remains uncertain whether cells lack of CD34 and Lineage markers are the very best stem cells or maybe the residual embryonic stem cells keeping quiescent in the adult tissues are capable of transfer into hematopoietic stem cells when activated.

[More on Hematopoietic Stem Cell Research and Application Updated].

Allogeneic hematopoietic stem cell transplantation (HSCT) is an effective and proven treatment for malignant and nonmalignant diseases. Most of the natural HSC allografts hardly show overall advantages of high engraftment, slight GVHD and rare relapse. The graft engineering including stem cell engineering to make a tailor-made graft ex vivo is promising to conquer all the risks of low engraftment, lethal GVHD and high relapse, which becomes the key program in current HSC research.

The Presence of Endothelial Cell Precursors in Blood Circulation.

In the present study, an attempt was made to prove the question whether endothelial cell precursors exist in blood circulation during postnatal period. CD34(+) cells were harvested from G-CSF mobilized adult blood and umbilical cord blood and incubated onto fibronectin/gelatin-coated Petric dishes in the presence of recombinant human vascular endothelial cell growth factor(rhVEGF) and basic fibroblast growth factor(rhbFGF). Endothelial cell lineage was identified by von Willebrand factor(vWF) expression and Ulex europous agglutinin I(UEA-I) binding capacity.