The defectiveness of bone marrow mesenchymal stem cells (BM-MSCs) in acquired aplastic anemia (AA) has been a frequent research topic in recent years. This review summarizes the defectiveness of BM-MSCs which is responsible for the mechanism of acquired AA and the prospective application of BM-MSCs in the treatment of acquired AA. An increasingly number of laboratory statistics has demonstrated that the defectiveness of BM-MSCs is more likely to play an important role in the pathogenesis of AA, namely, the apparently different biological characteristics and gene expression profiles, the decreased ability of supporting hematopoiesis as well as self-renewal and differentiation, and the exhaustion of regulating immune response of hematopoietic environment. Those abnormalities continuously prompt AA to become irreversible bone marrow failure along with the imbalanced immunity. With deepening research on MSCs, infusion of MSCs for the primary purpose of recovering hematopoietic microenvironment may become a new approach for the treatment of AA.
Anemia, Aplastic ; etiology ; immunology ; therapy ; Bone Marrow ; Cell Differentiation ; Cell Proliferation ; Cytokines ; analysis ; Humans ; Lymphocyte Activation ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stromal Cells ; physiology ; T-Lymphocytes, Regulatory ; immunology

Xerostomia is a severe side effect of radiation therapy in head and neck cancer patients. To date, no satisfactory treatment option has been established. Because mesenchymal stem cells (MSCs) have been identified as a potential treatment modality, we aimed to evaluate stem cell distribution following intravenous and intraglandular injections using a surgical model of salivary gland damage and to analyse the effects of MSC injections on the recruitment of immune cells. The submandibular gland ducts of rats were surgically ligated. Syngeneic adult MSCs were isolated, immortalised by simian virus 40 (SV40) large T antigen and characterized by flow cytometry. MSCs were injected intravenously and intraglandularly. After 1, 3 and 7 days, the organs of interest were analysed for stem cell recruitment. Inflammation was analysed by immunohistochemical staining. We were able to demonstrate that, after intravenous injection, MSCs were recruited to normal and damaged submandibular glands on days 1, 3 and 7. Unexpectedly, stem cells were recruited to ligated and non-ligated glands in a comparable manner. After intraglandular injection of MSCs into ligated glands, the presence of MSCs, leucocytes and macrophages was enhanced, compared to intravenous injection of stem cells. Our data suggest that injected MSCs were retained within the inflamed glands, could become activated and subsequently recruited leucocytes to the sites of tissue damage.
Animals ; Antigens, Polyomavirus Transforming ; immunology ; Cell Culture Techniques ; Cell Movement ; physiology ; Cell Transformation, Viral ; Clone Cells ; physiology ; Flow Cytometry ; Immunohistochemistry ; Injections, Intralesional ; Injections, Intravenous ; Leukocytes ; pathology ; Macrophages ; pathology ; Mesenchymal Stem Cell Transplantation ; methods ; Mesenchymal Stromal Cells ; pathology ; physiology ; Necrosis ; Rats, Wistar ; Salivary Ducts ; pathology ; Sialadenitis ; pathology ; therapy ; Simian virus 40 ; immunology ; Submandibular Gland ; pathology ; Submandibular Gland Diseases ; pathology ; therapy ; Time Factors

Mesenchymal stem cells (MSCs) are self-renewing, multipotent progenitor cells with multilineage potential to differentiate into cell types of mesodermal origin, such as adipocytes, osteocytes, and chondrocytes. In addition, MSCs can migrate to sites of inflammation and exert potent immunosuppressive and anti-inflammatory effects through interactions between lymphocytes associated with both the innate and adaptive immune system. Along with these unique therapeutic properties, their ease of accessibility and expansion suggest that use of MSCs may be a useful therapeutic approach for various disorders. In the clinical setting, MSCs are being explored in trials of various conditions, including orthopedic injuries, graft versus host disease following bone marrow transplantation, cardiovascular diseases, autoimmune diseases, and liver diseases. Furthermore, genetic modification of MSCs to overexpress antitumor genes has provided prospects for clinical use as anticancer therapy. Here, we highlight the currently reported uses of MSCs in clinical trials and discuss their efficacy as well as their limitations.
Animals ; Cell Differentiation ; Cell Lineage ; Cell Movement ; Cell Proliferation ; Gene Expression Regulation ; Humans ; *Mesenchymal Stem Cell Transplantation/adverse effects ; Mesenchymal Stromal Cells/immunology/*physiology ; *Regeneration ; Regenerative Medicine/*methods ; Treatment Outcome

Mesenchymal stem cells have generated great interest among researchers and physicians due to their unique biological characteristics and potential clinical applications. Here, I propose for the first time the concept of a hierarchical system which is composed of all mesenchymal stem cells from post-embryonic subtotipotent stem cells to MSC progenitors. Post-embryonic subtotipotent stem cells are left-over cells during embryonic development and are on the top of the hierarchy. MSC system is a combination of cells that are derived from different stages of embryonic development, possess different differentiation potential and ultimately give rise to cells that share a similar set of phenotypic markers. The concept of MSC system has important implications: (1) it entirely explains the three important biological characteristics of MSC: stem cell properties of MSC, MSC as components of tissue microenvironment and immunomodulatory functions of MSC. (2) It balances immune responses and tissue metabolism. (3) It could provide tissue-specific stem cells for clinical application with high efficiency and safety. In a word, this concept constitutes an important part of the biological properties of MSC and will help researchers gain better insight into MSC.
Cell Differentiation ; Cellular Microenvironment ; Humans ; Immunomodulation ; Mesenchymal Stromal Cells ; immunology ; physiology ; Phenotype

OBJECTIVETo investigate the effects of B7H4 on human bone marrow mesenchymal stem cells (HBMSC) mediating immune suppression.

METHODSThe expression of the negative immunoregulatory factor B7H4 on HBMSC were analyzed by RT-PCR and flow cytometry (FCM), respectively. The blocking experiment was used to detect the effects of B7H4 on HBMSC mediating suppression on PHA induced T cell activation, proliferation and cell cycle. HBMSC inhibiting T cell proliferation was examined by transwell cell culture system.

RESULTSB7H4 was highly expressed on HBMSC. Blocking the B7H4 expression by B7H4mAb significantly attenuated the inhibitory effects of HBMSC on T cell proliferation. Compared with that of the unblocking group, T cell stimulator index (SI) of the B7H4 blocked group was significantly increased (53 +/- 5 vs 15 +/- 8, P < 0.01) and the inhibitory effects of HBMSC on T cell cycle were weakened significantly through down-regulating the cell number in G(0)/G(1) phase \[(85.6 +/- 9.9)% vs (95.8 +/- 9.9)%\] and up-regulating those in S phase\[(5.8 +/- 3.2)% vs (2.3 +/- 2.2)%, P < 0.05\]. The suppressive effects of HBMSC on T cell proliferation were significantly weakened after separating HBMSC from T cells by transwell cell culture system. Compared with the cell to cell contact group, T cell SI was significantly increased (27 +/- 17 vs 15 +/- 3, P < 0.01).

CONCLUSIONHBMSC highly express B7H4, which plays an important role in the suppressive effects of HBMSC on T cell proliferation.

B7-1 Antigen ; metabolism ; physiology ; Bone Marrow Cells ; immunology ; metabolism ; Cell Cycle ; immunology ; Cell Proliferation ; Cells, Cultured ; Humans ; Lymphocyte Activation ; drug effects ; immunology ; Mesenchymal Stromal Cells ; immunology ; metabolism ; Phytohemagglutinins ; pharmacology ; T-Lymphocytes ; cytology ; drug effects ; immunology ; V-Set Domain-Containing T-Cell Activation Inhibitor 1

The study was aimed to investigate the potential immunotherapeutical values of umbilical cord tissue-derived mesenchymal stem cells (UC-MSC) on patients with chronic idiopathic thrombocytopenic purpura (ITP). UC-MSC was cocultured in vitro with splenocytes isolated from ITP patients who experienced splenectomy. The level of IgG antiplatelet antibody (PAIgG) was determined by a competitive micro-enzyme-linked immunosorbent assay (ELISA) method. The proliferation of platelet-reactive CD4+ T lymphocytes was also measured in the presence of UC-MSCs. The results showed that UC-MSCs could stimulate the spontaneous secretion of PAIgG in supernatants; In the platelet-inducing condition, UC-MSC inhibited the production of PAIgG at a low ratio of 1 UC-MSC to 100 splenocytes, but promoted at a high proportion of 1 UC-MSC to 10 splenocytes. Moreover, UC-MSC exerted a suppressive effect on proliferation of platelet-reactive T helper cells in a dose-dependent manner. It is concluded that the UC-MSCs can regulate secretion of antiplatelet antibodies in vitro. Its concrete regulation mechanism and potential immunotherapeutical value are need to further study.
Antibodies ; metabolism ; Blood Platelets ; immunology ; CD4-Positive T-Lymphocytes ; cytology ; Cell Proliferation ; Humans ; Infant, Newborn ; Lymphocyte Activation ; Mesenchymal Stromal Cells ; physiology ; Purpura, Thrombocytopenic, Idiopathic ; metabolism ; Spleen ; cytology ; Umbilical Cord ; physiology

The study was aimed to compare the effects of T-cell suppression mediated by mesenchymal stem cells (MSC) from normal individuals and myelodysplastic syndromes (MDS) patients. MSC were cultured from the bone marrow of 12 healthy volunteers and 12 MDS patients, the morphology, surface markers and expression of several cytokines of MSC from normal individuals and MDS patients were compared, and the effects of T-cell suppression were tested in the following assays: phytohemaglutinin (PHA)-primed cultures, mixed lymphocyte reaction (MLR), cell cycle of T-cell after PHA-primed cultures and apoptosis of T-cell as well. The results showed that the MSC from normal individuals and MDS patients were similar in morphology, proliferation and surface markers. The suppressions of T-cell proliferation induced by PHA and alloantigens mediated by MDS-MSC were significantly lower than that of normal MSC. More T-cells were arrested in G0/G1 phase by normal MSC, while the effects were deficient by MDS-MSC. The suppression of T-cell activation mediated by MDS-MSC was also lower than that of normal MSC, but suppression effect on T-cell apoptosis increased. The cytokines TGF-beta1, 3, FasL expressed by MDS-MSC were reduced as compared with normal MSC, but TGF-beta2 expression increased in MDS-MSC. It is concluded that although the morphology, proliferation and cell surface markers of MDS-MSC are normal, the T-cell suppression mediated by MDS-MSC is deficient as compared with normal controls. Whether these abnormalities are relevant to the pathogenesis of aplastic anemia remains to be determined.
Adult ; Aged ; Bone Marrow Cells ; cytology ; physiology ; Female ; Humans ; Immune Tolerance ; immunology ; physiology ; Male ; Mesenchymal Stromal Cells ; immunology ; physiology ; Middle Aged ; Myelodysplastic Syndromes ; immunology ; pathology ; T-Lymphocytes ; immunology

This study was purposed to investigate the immunoregulatory effect of endothelial cells derived from mesenchymal stem cells (MSC). The human MSC was induced to differentiate into endothelial cells for one week. The phenotypes were evaluated by flow cytometry, the cell morphologic feature was observed by invert phase-contrast microscope and analysis of capillary formation was performed by using the in vitro angiogenesis kit. The immunoregulatory effect was detected by lymphocyte transformation test. The result indicated that during the differentiation cells grew fast and there was no significant change in the phenotypes, i.e. CD73, CD105, HLA-ABC were positive and CD34, CD80, CD86, HLA-DR, CD31 were negative. Immunofluorescence analysis showed typical expression of the von Willebrand factor. Differentiated MSCs formed capillary-like structure. Endothelial cells derived from MSC also revealed immunosuppressive effect on T cell proliferation in a dose-dependent manner. It is concluded that endothelial cells derived from MSC also harbor immunoregulatory effect on T lymphocytes.
5'-Nucleotidase ; metabolism ; Cell Differentiation ; physiology ; Cells, Cultured ; Child ; Endothelial Cells ; cytology ; immunology ; Humans ; Mesenchymal Stromal Cells ; cytology ; metabolism ; T-Lymphocytes ; immunology ; von Willebrand Factor ; metabolism

BACKGROUNDThe coordinated change of haematopoietic supporting microenvironment in bone marrow (BM) is crucial for innate immunity and inflammation. As the precursors of marrow stroma, BM derived mesenchymal stem cells (MSCs) promote haematopoietic function, but their roles in innate immunity or inflammation have not been investigated. Here we investigated the expression of Toll like receptor 4 (TLR-4) and the effect of lipopolysaccharide (LPS) on its expression in BM MSCs in vitro.

METHODSMSCs were harvested from adult rat's BM cells by density gradient centrifugation and adhesive culture. The purity of MSCs were identified with the cell morphological feature and osteogenic capacity, the phenotypes were tested by flow cytometry. Cultured MSCs were treated by LPS (1 microg/ml, 10 microg/ml or 100 microg/ml) for 24 hours. The relative expression levels of TLR-4 mRNA were detected by semiquantitative reverse transcription polymerase chain reaction and costimulatory molecules (CD80, CD86 and MHC-II) expressed on MSCs were analyzed by flow cytometry. The levels of tumor necrosis factor-alpha (TNF-alpha) in supernatants were determined by enzyme linked immunosorbent assay.

RESULTSAfter incubation with LPS, MSCs expressed the higher levels of TLR-4 mRNA, costimulatory molecules and TNF-alpha than the untreated group: LPS 10 microg/ml was the most effective (P < 0.01); the levels of TLR-4 mRNA, costimulatory molecules and TNF-alpha decreased when MSCs were exposed to 100 microg/ml LPS. Except for MHC-II and TNF-alpha (P > 0.05), the levels of CD80, CD86 and TLR-4 mRNA were significantly lower than that in the treated group of 10 microg/ml (P < 0.01).

CONCLUSIONMSCs expressed TLR-4 mRNA. LPS activated the functional expression levels of TLR-4 in MSCs although the activity may depend on the concentration of LPS.

Animals ; B7-2 Antigen ; analysis ; Bone Marrow Cells ; immunology ; Cell Differentiation ; Cells, Cultured ; Immunophenotyping ; Lipopolysaccharides ; pharmacology ; Male ; Mesenchymal Stromal Cells ; drug effects ; immunology ; Rats ; Rats, Sprague-Dawley ; Toll-Like Receptor 4 ; physiology ; Tumor Necrosis Factor-alpha ; biosynthesis ; Up-Regulation

The study was aimed to isolate and establish mesenchymal stem cell line from adult murine bone marrow as well as to identify its biological characteristics and differentiation potential. Bone marrow cells (BMCs) were collected by flushing the femurs and tibias of 4 - 5-week-old male C57BL/6 mice, and were inoculated at a concentration of 1 x 10(6)/cm(2). mMSCs were isolated, enriched and expanded by using bone marrow adherant culture and monoclonal culture. The characteristics of the cells, such as morphology, growth pattern, cell cycle, phenotype, karyotype and multipotent differentiation potential, cytogenetic stability and tumorigenesis were determined. The results indicated that the cell population consisted of spindle- and star-shaped cells, they were highly positive for CD29, CD44, Sca-1, MHC-I, moderate positive for CD13, CD90.2 and negative for CD117, CD45, Flk-1 and MHC-II. mMSCs could be induced to differentiate into adipocytes, osteoblast cells and chondrocytes. It is concluded that mMSC can be isolted, expanded and enriched by using bone marrow adhcrent culture and monoclonal culture. No tumor formations are observed for 3 months in nude mice after subcutaneous injection. mMSCs retain their properties after at least 30 passages in culture as well as from frozen stocks.
Animals ; Cell Differentiation ; physiology ; Cell Proliferation ; Cell Separation ; methods ; Cells, Cultured ; Hyaluronan Receptors ; metabolism ; Integrin beta1 ; metabolism ; Male ; Mesenchymal Stromal Cells ; cytology ; immunology ; physiology ; Mice ; Mice, Inbred C57BL ; Mice, Nude