Mesenchymal Stromal Cells Populations Research Articles

Isolation and characterization of primary bone marrow mesenchymal stromal cells.

Bone marrow (BM) contains a rare population of mesenchymal stromal cells (MSCs), which have been characterized as nonhematopoietic skeletal progenitor cells with central importance for the hematopoietic microenvironment. Classically, MSCs are isolated by plastic adherence and subsequent culture. However, as cultured stromal cells differ from their in vivo progenitors, it is important to identify the phenotype of the primary MSCs to study these cells in more detail. In the past years, several surface markers have been reported to be suitable for effective enrichment of BM-MSCs, and recent data indicate that the putative MSC stem/progenitor cell population in human adult BM is highly enriched in Lin(-) CD45(-) CD271(+) CD140a (PDGFRα)(low/-) cells. Moreover, surface marker combinations have been described for the isolation of MSCs from murine BM. On the basis of these findings, the role of primary MSCs can now be studied in normal and, importantly, diseased BM. Furthermore, genetically engineered mouse models have been developed as powerful tools to investigate well-defined BM stromal cell populations in vivo. Our discussion aims to provide a concise overview of the current state of the art in BM-MSC isolation in humans and briefly present murine MSC isolation approaches and genetic models.

Can Targeting Stroma Pave the Way to Enhanced Antitumor Immunity and Immunotherapy of Solid Tumors?

Solid tumors are complex organ-like structures. The potential of normal neighboring cells to contribute to the initiation, progression, and metastasis of epithelial-derived carcinomas has long been appreciated. However, the role of host cells has proven complex. Through multiple local and systemic mechanisms, nontransformed host cells can promote transition from a tumor-resistant to tumor-permissive environment, drive neoplastic transformation of epithelial cells, promote tumor growth, progression, and metastasis, but also constrain tumorigenesis. This complexity reflects the spatially and temporally dynamic involvement of multiple cell types and processes, including the development and recruitment of inflammatory, immune, endothelial, and mesenchymal stromal cells, and the remodeling of extracellular matrix. Our mechanistic understanding, as well as our ability to translate advances in our understanding of these mechanisms for therapeutic benefit, is rapidly advancing. Further insights will depend on delineating pathways that mediate the communication networks between inflammatory and immune cells with tumor and mesenchymal stromal cells and extracellular matrix. Here, we discuss the diversity of mesenchymal stromal cell populations and how context can dictate either their promotion or constraint of tumorigenesis. We review evidence for plasticity that allows for reprogramming of stromal cells and how tumor immunogenicity and desmoplasia influence the balance of immune-independent and immune-dependent regulation of tumor growth. The pivotal roles of matrix and mesenchymal stromal cells in modulating inflammation, antitumor immunity, and the efficacy of immune-based therapies are discussed. These concepts have emerged from data obtained from tumors of multiple organs, but we focus mostly on studies of pancreatic ductal adenocarcinomas.

Wnt/β-Catenin Stimulation and Laminins Support Cardiovascular Cell Progenitor Expansion from Human Fetal Cardiac Mesenchymal Stromal Cells.

SummaryThe intrinsic regenerative capacity of human fetal cardiac mesenchymal stromal cells (MSCs) has not been fully characterized. Here we demonstrate that we can expand cells with characteristics of cardiovascular progenitor cells from the MSC population of human fetal hearts. Cells cultured on cardiac muscle laminin (LN)-based substrata in combination with stimulation of the canonical Wnt/β-catenin pathway showed increased gene expression of ISL1, OCT4, KDR, and NKX2.5. The majority of cells stained positive for PDGFR-α, ISL1, and NKX2.5, and subpopulations also expressed the progenitor markers TBX18, KDR, c-KIT, and SSEA-1. Upon culture of the cardiac MSCs in differentiation media and on relevant LNs, portions of the cells differentiated into spontaneously beating cardiomyocytes, and endothelial and smooth muscle-like cells. Our protocol for large-scale culture of human fetal cardiac MSCs enables future exploration of the regenerative functions of these cells in the context of myocardial injury in vitro and in vivo.

Evaluation of GMP-compliant culture media for invitro expansion of humanbone marrow mesenchymal stromal cells.

Mesenchymal stromal cells (MSCs) from human bone marrow serve as a resource for cell-based therapies in regenerative medicine. Clinical applications require standardized protocols according to good manufacturing practice (GMP) guidelines. Donor variability as well as the intrinsic heterogeneity of MSC populations must be taken into consideration. The composition of the culture medium is a key factor in successful MSC expansion. The aim of this study was to comparatively assess the efficiency of xeno-free human platelet lysate (HPL)-based cell expansion with two commercially available media-StemPro MSC SFM CTS (for human exvivo tissue and cell culture processing applications) and MSCGM (non-GMP-compliant, for research only)-in an academic setting as the first optimization step toward GMP-compliant manufacturing. We report the feasibility of MSC expansion up to the yielded cell number with all three media. MSCs exhibited the typical fibroblastoid morphology, with distinct differences in cell size depending on the medium. The differentiation capacity and characteristic immunophenotype were confirmed for all MSC populations. Proliferation was highest using StemPro MSC SFM CTS, whereas HPL medium was more cost-effective and its composition could be adjusted individually according to the respective needs. In summary, we present a comprehensive evaluation of GMP-compatible culture media for MSC expansion. Both StemPro and HPL medium proved to be suitable for clinical application and allowed sufficient cell proliferation. Specific differences were observed and should be considered according to the intended use. This study provides a detailed cost analysis and tools that may be helpful for the establishment of GMP-compliant MSC expansion.

Cisplatin-induced mesenchymal stromal cells-mediated mechanism contributing to decreased antitumor effect in breast cancer cells.

BackgroundCells of the tumor microenvironment are recognized as important determinants of the tumor biology. The adjacent non-malignant cells can regulate drug responses of the cancer cells by secreted paracrine factors and direct interactions with tumor cells.ResultsHuman mesenchymal stromal cells (MSC) actively contribute to tumor microenvironment. Here we focused on their response to chemotherapy as during the treatment these cells become affected. We have shown that the secretory phenotype and behavior of mesenchymal stromal cells influenced by cisplatin differs from the naïve MSC. MSC were more resistant to the concentrations of cisplatin, which was cytotoxic for tumor cells. They did not undergo apoptosis, but a part of MSC population underwent senescence. However, MSC pretreatment with cisplatin led to changes in phosphorylation profiles of many kinases and also increased secretion of IL-6 and IL-8 cytokines. These changes in cytokine and phosphorylation profile of MSC led to increased chemoresistance and stemness of breast cancer cells.ConclusionTaken together here we suggest that the exposure of the chemoresistant cells in the tumor microenvironment leads to substantial alterations and might lead to promotion of acquired microenvironment-mediated chemoresistance and stemness.

Nanopit-induced osteoprogenitor cell differentiation: The effect of nanopit depth

We aimed to assess osteogenesis in osteoprogenitor cells by nanopits and to assess optimal feature depth. Topographies of depth 80, 220 and 333 nm were embossed onto polycaprolactone discs. Bone marrow–derived mesenchymal stromal cells were seeded onto polycaprolactone discs, suspended in media and incubated. Samples were fixed after 3 and 28 days. Cells were stained for the adhesion molecule vinculin and the osteogenic transcription factor RUNX2 after 3 days. Adhesion was lowest on planar controls and it was the shallowest, and 80-nm-deep pits supported optimal adhesion formation. Deep pits (80 and 220 nm) induced most RUNX2 accumulation. After 28 days, osteocalcin and osteopontin expression were used as markers of osteoblastic differentiation. Deep pits (220 nm) produced cells with the highest concentrations of osteopontin and osteocalcin. All topographies induced higher expression levels than controls. We demonstrated stimulation of osteogenesis in a heterogeneous population of mesenchymal stromal cells. All nanopit depths gave promising results with an optimum depth of 220 nm after 28 days. Nanoscale modification of implant surfaces could optimise fracture union or osteointegration.

Restoration of a Critical Mandibular Bone Defect Using Human Alveolar Bone-Derived Stem Cells and Porous Nano-HA/Collagen/PLA Scaffold.

Periodontal bone defects occur in a wide variety of clinical situations. Adult stem cell- and biomaterial-based bone tissue regeneration are a promising alternative to natural bone grafts. Recent evidence has demonstrated that two populations of adult bone marrow mesenchymal stromal cells (BMSCs) can be distinguished based on their embryonic origins. These BMSCs are not interchangeable, as bones preferentially heal using cells that share the same embryonic origin. However, the feasibility of tissue engineering using human craniofacial BMSCs was unclear. The goal of this study was to explore human craniofacial BMSC-based therapy for the treatment of localized mandibular defects using a standardized, minimally invasive procedure. The BMSCs' identity was confirmed. Scanning electron microscopy, a cell proliferation assay, and supernatant detection indicated that the nHAC/PLA provided a suitable environment for aBMSCs. Real-time PCR and electrochemiluminescence immunoassays demonstrated that osteogenic markers were upregulated by osteogenic preinduction. Moreover, in a rabbit critical-size mandibular bone defect model, total bone formation in the nHAC/PLA + aBMSCs group was significantly higher than in the nHAC/PLA group but significantly lower than in the nHAC/PLA + preinduced aBMSCs. These findings demonstrate that this engineered bone is a valid alternative for the correction of mandibular bone defects.

Loss of TGF-β Signaling in Bone Marrow Mesenchymal Progenitors Promotes Adipocyte over Osteoblast Differentiation but Does Not Disrupt the HSC Niche

Hematopoietic stem cells (HSCs) reside in specialized microenvironments (niches) in the bone marrow. Several mesenchymal stromal cells have been implicated in hematopoietic niches, including osteoblasts, pericytes, CXCL12-abundant reticular (CAR) cells, and mesenchymal stem cells (MSCs). Members of the transforming growth factor (TGF) superfamily, in particular TGF-β, have a well-documented role in regulating osteoblast development. However, the contribution of TGF family member signaling to the establishment and maintenance of hematopoietic niches is largely unknown. Here, we characterize the role of transforming growth factor-β (TGF-β) signaling in mesenchymal stromal cells on the HSC niche.TGF-β receptor 2 (encoded by Tgfbr2) is required for all TGF-β signaling. To selectively disrupt TGF-β signaling in bone marrow mesenchymal stromal cells, we generated Osx-C re Tgfbr2fl/fl mice. Osx-Cre targets most bone marrow mesenchymal stromal cells (including osteoblasts, CAR cells, MSCs, pericytes, and adipocytes) but not endothelial cells or hematopoietic cells. Osx-C re Tgfbr2fl/fl mice are severely runted and most die by 4 weeks of age. We analyzed mice at 3 weeks, when the mice appeared healthy. Osteoblast number was severely reduced in Osx-C re Tgfbr2fl/fl mice, as assessed by histomorphometry and immunostaining for osteocalcin. Accordingly, microCT analysis demonstrated reduced tissue mineral density and cortical thickness of long bone and marked trabecularization of long bones in diaphyseal regions. Surprisingly, marrow adiposity, as measured by osmium tetroxide staining with microCT, was strikingly increased in Osx-C re Tgfbr2fl/fl mice. CAR cells are mesenchymal progenitors with osteogenic and adipogenic potential in vitro. To assess CAR cells, we generated Osx-Cre Tgfrb2fl/fl x Cxcl12gfp mice. Surprisingly, CAR cell number was significantly increased. However, despite the increase in CAR cells, the number of CFU-osteoblast (CFU-OB) in Osx-C re Tgfbr2fl/fl mice is nearly undetectable. Together, these data suggest that TGF-b signaling contributes to lineage commitment of mesenchymal progenitors. Specifically, our data suggest that TGF-β signaling suppresses commitment to the osteoblast lineage, while increasing adipogenic differentiation.We next asked whether alterations in bone marrow stromal cells present in Osx-C re Tgfbr2fl/fl mice affect HSC number or function. The increase in marrow adipocytes and loss of osteolineage cells is predicted to impair HSC maintenance, while the increase in CAR cells might augment HSCs. Osx-Cre Tgfrb2fl/fl mice have modest leukopenia, but normal red blood cell and platelet counts. Bone marrow and spleen cellularity are reduced, even after normalizing for body weight. The frequency of phenotypic HSCs (defined as Kit+ lineage- Sca+ CD34- Flk2- cells) is comparable to control mice. To assess HSC function, we performed competitive repopulation assays with bone marrow from Osx-Cre Tgfrb2fl/fl or control mice. Surprisingly, these data show that the long-term multi-lineage repopulating activity of HSCs from Osx-Cre Tgfrb2fl/fl mice is normal. Moreover, serial transplantation studies suggest that the self-renewal capacity of HSCs is normal. Thus, despite major alterations in mesenchymal stromal cell populations, the HSC niche is intact in Osx-Cre Tgfrb2fl/fl mice.Collectively, these data show that TGF-b signaling in mesenchymal progenitors is required for the proper development of multiple stromal cell populations that contribute to hematopoietic niches. Studies are underway to assess the impact of post-natal deletion of Tgfbr2 in mesenchymal stromal cell on hematopoietic niches. Since drugs that modulate the activity of TGF-b are in development, this research may suggest novel approaches to modulate hematopoietic niches for therapeutic benefit. DisclosuresNo relevant conflicts of interest to declare.

Mesenchymal Cell Associated Fibrosis in Experimental mplW515L Mouse Model of Myelofibrosis

Background: Bone marrow fibrosis caused by excessive collagen deposition represents a significant indicator of poor prognosis in myeloproliferative neoplasms (MPNs). Genetic driver mutations have been identified as JAK2, CALR and mpl, but the precise mechanism and cell type leading to fibrosis remains unanswered. TGFβ production by mutant hematopoietic cells is the primary factor responsible for fibrosis initiation. Although effective JAK2 inhibitor therapy has been adopted to manage disease symptoms and decrease abnormal hematopoietic cells, this pharmacological inhibitor does not reverse fibrosis. Our previous observations in patients with Large granular lymphocyte (LGL) leukemia indicate that mesenchymal-derived fibroblasts, distinguished by the capacity to undergo trilineage differentiation into osteoblasts, adipocytes and chondrocytes, are responsible for the fibrosis observed in these patients. In this study, we report the identification of a similar fibrosis-initiating mesenchymal cell population in a mouse model of MPN induced by transplantation of gfp-mplW515L retrovirus-expressing hematopoietic cells and indicate a mechanism to reverse the fibrotic phenotype.Methods: Primary mesenchymal stromal cells (MSCs) were isolated from mice with MPN caused by the transplantation of gfp-mplW515L -transduced bone marrow cells (MPN mice) and from control mice that received transplants with gfp-wild-type(wt)-mpl-expressing bone marrow. MSCs were harvested 17 days post-transplant when WBC counts exceeded at least >20,000 cells/μl. Fibrillar collagen I (detected with trichrome stain in bone marrow biopsies) and collagen III (detected with reticulin stain in bone marrow biopsies) were identified as the major proteins produced in the bone marrow and by cultured MSCs in MPN mice consistent with pathologic examination. The amount of collagen was quantified in MSCs grown under reduced oxygen in undifferentiating culture conditions. To determine pluripotency, cells were grown with differentiation-specific culture media and stained with Alizarin Red S (to detect osteoblasts) and Alcian blue (chondrocytes). Collagen production was determined by qRT-PCR and polychromatic immunofluorescence staining of three-dimensional cultures and TGFβ was measured by qRT-PCR and ELISA.Results: To isolate purified populations of MSCs, gfp-positive hematopoietic cells were removed and MSCs were maintained in long-term culture in the absence of malignant cells. MSCs were isolated in micro-cultures from gfp-wt-mpl (ie, control) and mplW515L transplanted mice. Using gfp-wt-mpl-derived MSCs, we first showed that the addition of TGFβ induced collagen I and III expression as expected from previous studies. Original undifferentiated MSCs derived from control and MPN mice grew continuously in undifferentiated culture conditions with a similar life expectancy, and both populations were capable of further differentiation into osteoblasts and chondrocytes. Collagen I (p<0.0001) and III (p=0.0008) mRNA and fiber formation were increased in the MSCs from mplW515L -transplanted mice compared to control. Without exogenous cytokines or HSC supernatant, the MSCs from mutant-mpl-mice maintained greater than 2-fold increase in collagen suggesting that intrinsic reprogramming occurred in the MSC population independent of tumor cells that are normally considered the source of TGFβ and other fibrosis-initiating cytokines. TGFβ mRNA (0.9878±0.129, control vs 1.023±0.319, MPN p=ns) and total TGFβ secreted protein detected by ELISA (165.0±22.7pg/ml, control vs 144.1±21.8pg/ml, MPN p=ns) was similar in control and MPN-derived MSCs indicating that excessive TGFβ production does not maintain the fibrotic phenotype in culture. We have shown previously that collagen from fibrotic MSCs in LGL leukemia is inhibited by culturing the cells with fibroblast growth factor-b (FGFb, FGF-2). Similar to LGL leukemia-dervied MSCs, the addition of FGFb stimulated proliferation and restored normal levels of collagen I and III in the MSCs from MPN mice.Conclusions: This study indicates that expanded MPN-derived MSCs can be re-programmed to produce normal amounts of collagen, which may reverse fibrosis. This study has implications for the development of MSC-based cell therapies in MPN. DisclosuresNo relevant conflicts of interest to declare.

Transcriptomic comparisons between cultured human adipose tissue-derived pericytes and mesenchymal stromal cells

Mesenchymal stromal cells (MSCs), sometimes called mesenchymal stem cells, are cultured cells able to give rise to mature mesenchymal cells such as adipocytes, osteoblasts, and chondrocytes, and to secrete a wide range of trophic and immunomodulatory molecules. Evidence indicates that pericytes, cells that surround and maintain physical connections with endothelial cells in blood vessels, can give rise to MSCs (da Silva Meirelles et al., 2008 [1]; Caplan and Correa, 2011 [2]). We have compared the transcriptomes of highly purified, human adipose tissue pericytes subjected to culture-expansion in pericyte medium or MSC medium, with that of human adipose tissue MSCs isolated with traditional methods to test the hypothesis that their transcriptomes are similar (da Silva Meirelles et al., 2015 [3]). Here, we provide further information and analyses of microarray data from three pericyte populations cultured in pericyte medium, three pericyte populations cultured in MSC medium, and three adipose tissue MSC populations deposited in the Gene Expression Omnibus under accession number GSE67747.

Three-dimensional spheroid cell culture of umbilical cord tissue-derived mesenchymal stromal cells leads to enhanced paracrine induction of wound healing.

IntroductionThe secretion of trophic factors by mesenchymal stromal cells has gained increased interest given the benefits it may bring to the treatment of a variety of traumatic injuries such as skin wounds. Herein, we report on a three-dimensional culture-based method to improve the paracrine activity of a specific population of umbilical cord tissue-derived mesenchymal stromal cells (UCX®) towards the application of conditioned medium for the treatment of cutaneous wounds.MethodsA UCX® three-dimensional culture model was developed and characterized with respect to spheroid formation, cell phenotype and cell viability. The secretion by UCX® spheroids of extracellular matrix proteins and trophic factors involved in the wound-healing process was analysed. The skin regenerative potential of UCX® three-dimensional culture-derived conditioned medium (CM3D) was also assessed in vitro and in vivo against UCX® two-dimensional culture-derived conditioned medium (CM2D) using scratch and tubulogenesis assays and a rat wound splinting model, respectively.ResultsUCX® spheroids kept in our three-dimensional system remained viable and multipotent and secreted considerable amounts of vascular endothelial growth factor A, which was undetected in two-dimensional cultures, and higher amounts of matrix metalloproteinase-2, matrix metalloproteinase-9, hepatocyte growth factor, transforming growth factor β1, granulocyte-colony stimulating factor, fibroblast growth factor 2 and interleukin-6, when compared to CM2D. Furthermore, CM3D significantly enhanced elastin production and migration of keratinocytes and fibroblasts in vitro. In turn, tubulogenesis assays revealed increased capillary maturation in the presence of CM3D, as seen by a significant increase in capillary thickness and length when compared to CM2D, and increased branching points and capillary number when compared to basal medium. Finally, CM3D-treated wounds presented signs of faster and better resolution when compared to untreated and CM2D-treated wounds in vivo. Although CM2D proved to be beneficial, CM3D-treated wounds revealed a completely regenerated tissue by day 14 after excisions, with a more mature vascular system already showing glands and hair follicles.ConclusionsThis work unravels an important alternative to the use of cells in the final formulation of advanced therapy medicinal products by providing a proof of concept that a reproducible system for the production of UCX®-conditioned medium can be used to prime a secretome for eventual clinical applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0082-5) contains supplementary material, which is available to authorized users.

The Human Umbilical Cord Tissue-Derived MSC Population UCX®Promotes Early Motogenic Effects on Keratinocytes and Fibroblasts and G-CSF-Mediated Mobilization of BM-MSCs when Transplanted In Vivo

Mesenchymal stromal cells (MSCs) play an important role in tissue regeneration mainly through the secretion of trophic factors that enhance the repair of damaged tissues. The main goal of this work was to study the paracrine mechanisms by which an umbilical cord tissue-derived MSC population (UCX(®)) promotes the migration capacity of human dermal fibroblasts and keratinocytes, which is highly relevant for skin regeneration. Furthermore, the differences between paracrine activities of MSCs from the umbilical cord tissue and the bone marrow (BM-MSCs) were also evaluated. In vitro scratch assays revealed that conditioned media (CM) obtained from both growing and stationary-phase UCX(®) cultures induced human dermal fibroblast (HDF) and keratinocyte (HaCaT) migration. These assays showed that the motogenic activity of UCX(®) CM to HaCaTs was significantly higher than to HDFs, in opposition to the effect seen with CM produced by BM-MSCs that preferentially induced HDF migration. Accordingly, a comparative quantification of key factors with vital importance in the consecutive stages of wound healing revealed very different secretome profiles between UCX(®) and BM-MSCs. The relatively higher UCX(®) expression of EGF, FGF-2, and KGF strongly supports early induction of keratinocyte migration and function, whereas the UCX(®)-specific expression of G-CSF suggested additional roles in mobilization of healing-related cells including CD34(-)/CD45(-) precursors (MSCs) known to be involved in tissue regeneration. Accordingly, in vitro chemotaxis assays and an in vivo transplantation model for chemoattraction confirmed that UCX(®) are chemotactic to CD34(-)/CD45(-) BM-MSCs via a cell-specific mobilization mechanism mediated by G-CSF. Overall, the results strongly suggest different paracrine activities between MSCs derived from different tissue sources, revealing the potential of UCX(®) to extend the regenerative capacity of the organism by complementing the role of endogenous BM-MSCs.

MP19-13 DEVELOPMENT OF A LARGE XENOGRAFT ANIMAL MODEL TO INVSTIGATE EFFICACY OF CELL-BASED THERAPIES TO TREAT STRESS URINARY INCONTINENCE

You have accessJournal of UrologyStem Cell Research1 Apr 2015MP19-13 DEVELOPMENT OF A LARGE XENOGRAFT ANIMAL MODEL TO INVSTIGATE EFFICACY OF CELL-BASED THERAPIES TO TREAT STRESS URINARY INCONTINENCE Bastian Amend, Alexandra Kelp, Martin Vaegler, Arnulf Stenzl, and Karl-Dietrich Sievert Bastian AmendBastian Amend More articles by this author , Alexandra KelpAlexandra Kelp More articles by this author , Martin VaeglerMartin Vaegler More articles by this author , Arnulf StenzlArnulf Stenzl More articles by this author , and Karl-Dietrich SievertKarl-Dietrich Sievert More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1005AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Currently, a functional cure for stress urinary incontinence (SUI) does not exist. The only feasible treatment is to ameliorate symptoms. Application of regeneration-competent progenitor or stem cells could possibly restore function of the rhabdosphincter. This study aims to develop a large animal model that incorporates safe, yet precise cell injection technologies, to investigate localization, distribution, survival, and possible integration of human mesenchymal stromal cells (MSC) after injection in the bladder sphincter muscle of minipigs. METHODS Undifferentiated different human MSC (bone marrow, placenta or adipose tissue) were injected into the rhabdosphincter (4 depots,2x106 cells in total) by transurethral-guided needle injection. Seventy-two immune-supressed female minipigs were divided into 12 groups with six animals each: 3 groups of MSC populations consisting of 4 follow-up points (3w,3m,6m,and 12m). Sham (24) underwent treatment with culture media. Functional regeneration of rhabdosphincter was evaluated by urodynamic urethral pressure profile(UPP) at above mentioned follow-up. The rhabdosphincter was harvested for further investigation. General histology was performed at the localization, distribution of MSC on cryostat sections as well as TUNEL-staining for the apoptosis rate. RESULTS Prior to initial MSC treatment, all animals received an MSC treatment Cyclosporine®(15mg/kg, iv) and continued orally post-operatively. Six did not survive; 5 from sham group and 1 that received cells. All animals tested (n=59/72) did not demonstrate signs of human MSC rejection nor inflammation. Only in 1/59, a fibrotic encapsulation of MSC injected was observed. The 59 urodynamic-investigated pigs demonstrated a functional increased UPP compared to sham without differences related to MSC source. During all tested evaluation points, cells remained in the region of injection without migration and/or disappearance. Over time the depots appeared to decrease. Throughout the investigation, apoptosis was present in ≤10% of injected MCS locations according to TUNEL-staining in the depots, whereas the host tissue had an average apoptosis of 2%. CONCLUSIONS Immune-supressed minipigs served as a model in preclinical cell therapy studies. Transurethral needle injection of human MSC is feasible and potential minimal-invasive application technique for clinical regeneration of injured and degenerated rhabdosphincter in the future, given that injected cells survived and effected functional regeneration. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e220 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Bastian Amend More articles by this author Alexandra Kelp More articles by this author Martin Vaegler More articles by this author Arnulf Stenzl More articles by this author Karl-Dietrich Sievert More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Therapeutic potential of ixmyelocel-T, an expanded autologous multicellular therapy for treatment of ischemic cardiovascular diseases.

IntroductionBone marrow derived cellular therapies are an emerging approach to promoting therapeutic angiogenesis in ischemic cardiovascular disease. However, the percentage of regenerative cells in bone marrow mononuclear cells (BMMNCs) is small, and large amounts of BMMNCs are required. Ixmyelocel-T, an expanded autologous multicellular therapy, is manufactured from a small sample of bone marrow aspirate. Ixmyelocel-T contains expanded populations of mesenchymal stromal cells (MSCs) and M2-like macrophages, as well as many of the CD45+ cells found in the bone marrow. It is hypothesized that this expanded multi-cellular therapy would induce angiogenesis and endothelial repair.MethodsA rat model of hind limb ischemia was used to determine the effects of ixmyelocel-T on blood flow recovery. To further determine the effects on endothelial cells, ixmyelocel-T was co-cultured with human umbilical vein endothelial cells (HUVEC) in non-contacting Transwell® inserts.ResultsCo-culture of HUVECs with ixmyelocel-T resulted secretion of a variety of pro-angiogenic factors. HUVECs stimulated by ixmyelocel-T exhibited enhanced migration, proliferation, and branch formation. Ixmyelocel-T co-culture also resulted in increased endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production. In tumor necrosis factor alpha (TNFα)-stimulated HUVECs, ixmyelocel-T co-culture decreased apoptosis and reactive oxygen species generation, increased super oxide dismutase activity, and decreased nuclear factor kappa B (NFκB) activation. Treatment with ixmyelocel-T in a rat model of hind limb ischemia resulted in significantly increased blood flow perfusion and capillary density, gene expression and plasma levels of the anti-inflammatory cytokine interleukin (IL)-10, plasma nitrates, plasma platelet-derived growth factor (PDGF)-BB, vascular endothelial growth factor (VEGF) expression, and significantly decreased plasma thiobarbituric acid reactive substances (TBARS).ConclusionsThis work demonstrates that ixmyelocel-T interacts with endothelial cells in a paracrine manner, resulting in angiogenesis and endothelial protection. This data suggests that ixmyelocel-T could be useful for promoting of angiogenesis and tissue repair in ischemic cardiovascular diseases. In conclusion, ixmyelocel-T therapy may provide a new aspect of therapeutic angiogenesis in this patient population where expanded populations of regenerative cells might be required.

Endogenous mesenchymal stromal cells in bone marrow are required to preserve muscle function in mdx mice.

The physiological role of "endogenous" bone marrow (BM) mesenchymal stromal cells (MSCs) in tissue regeneration is poorly understood. Here, we show the significant contribution of unique endogenous BM-MSC populations to muscle regeneration in Duchenne muscular dystrophy (DMD) mice (mdx). Transplantation of BM cells (BMCs) from 10-week-old mdx into 3-4-week-old mdx mice increased inflammation and fibrosis and reduced muscle function compared with mdx mice that received BMCs from 10-week-old wild-type mice, suggesting that the alteration of BMC populations in mdx mice affects the progression of muscle pathology. Two distinct MSC populations in BM, that is, hematopoietic lineage (Lin)(-) /ckit(-) /CD106(+) /CD44(+) and Lin(-) /ckit(-) /CD106(+) /CD44(-) cells, were significantly reduced in 10-week-old mdx mice in disease progression. The results of a whole-transcriptome analysis indicated that these two MSC populations have distinct gene expression profiles, indicating that the Lin(-) /ckit(-) /CD106(+) /CD44(+) and Lin(-) /ckit(-) /CD106(+) /CD44(-) MSC populations are proliferative- and dormant-state populations in BM, respectively. BM-derived Lin(-) /CD106(+) /CD44(+) MSCs abundantly migrated to damaged muscles and highly expressed tumor necrosis factor-alpha-stimulated gene/protein-6 (TSG-6), an anti-inflammatory protein, in damaged muscles. We also demonstrated that TSG-6 stimulated myoblast proliferation. The injection of Lin(-) /ckit(-) /CD106(+) /CD44(+) MSCs into the muscle of mdx mice successfully ameliorated muscle dysfunction by decreasing inflammation and enhancing muscle regeneration through TSG-6-mediated activities. Thus, we propose a novel function of the unique endogenous BM-MSC population, which countered muscle pathology progression in a DMD model.

Are MSCs Stem Cells? Demonstration of in Vitro and in Vivo Stem Cell Properties of Highly Enriched linneg/CD45neg/CD271pos/CD140alow/Neg Mesenchymal Stromal Cells from Adult Human Bone Marrow

Human bone marrow contains a rare population of non-hematopoietic mesenchymal stromal cells (BM-MSC) with multilineage differentiation capacity, which are essential constituents of the hematopoietic microenvironment. Self-renewal and differentiation are the two key properties of somatic stem cells, however, stem cell properties of human adult BM-MSC have not been demonstrated conclusively yet. We have previously shown that low/negative expression of PDGFRα on linneg/CD45neg/CD271pos cells identified a highly enriched population of primary BM-MSC in adult human bone marrow (Li et al. Blood, 2013, 122:3699). Based on this work, the current study aimed to investigate the in-vitro and in-vivo stem cell properties of this putative stromal stem cell population.The in-vitro clonogenic potential of freshly sorted human linneg/CD45neg/CD271pos/PDGFRlow/neg cells was evaluated by utilizing the CFU-F assay as well as the recently-developed mesensphere assay, which enables MSC amplification while preserving an immature phenotype (Isern et al, Cell Reports 2013, 30: 1714-24). Comparable colony frequencies were obtained with both assays (19.3 ± 2 and 17.5 ± 2.3 CFU-F and spheres per 100 plated cells, respectively, n=6, p=0.19). In order to test whether both assays identified the same population of clonogenic cells, colonies and spheres were replated under both conditions for up to three generations. The results showed comparable capacities of CFU-F and mesenspheres to form secondary and tertiary CFU-F and spheres. In-vitro self-renewal as indicated by increasing numbers of CFU-F and spheres (416.6 ± 431.7-fold and 49.5 ± 65.7-fold, respectively, n=3) was observed up to the third generation and decreased thereafter. The total number of generations was five (CFU-F) and six (spheres). In-vitro differentiation assays with both, CFU-F- and sphere-derived cells (tested until passage three) demonstrated tri-lineage differentiation potential (adipocytes, osteoblasts, chondrocytes). In addition, CFU-Fs and spheres had comparable surface marker profiles (CD73, CD90, CD105, and HLA-ABC positive; CD31, CD34 and HLA-DR negative), except for CD90, which was higher expressed on CFU-Fs.To investigate in-vivo self-renewal and differentiation potential of the putative stromal stem cells, linneg/CD45neg/CD271pos/PDGFRlow/neg -derived CFU-F and spheres were serially transplanted s.c into NSG mice. After 8 weeks, implants were harvested, human cells were FACS-isolated (CD90 and CD105 expression), and re-assayed under CFU-F and sphere conditions. Whereas in-vivo self-renewal of CFU-F could not be shown (111.5 ± 36 –fold decrease in total CFU-F numbers after primary transplantation, n=3), sphere self-renewal was clearly demonstrated by increased numbers of spheres after primary as well as secondary transplantation (1.13 ± 0.05 and 2.06 ± 0.26 –fold, respectively, n=3), which is remarkable given the fact that the number of recovered human cells is underestimated due to the isolation approach. Here, confirming GFP-marking experiments are ongoing. Finally, preliminary data indicate that linneg/CD45neg/CD271pos/PDGFRlow/neg –derived spheres display full in-vivo differentiation capacity in primary and secondary transplantations.Taken together, our data demonstrate - for the first time - that primary human linneg/CD45neg/CD271pos/PDGFRlow/neg cells meet stringent stem cell criteria, i.e. in-vitro and in-vivo self-renewal and differentiation. These findings answer the long-open question of the potential stem cell properties of adult human MSC and will enable to better understand the properties of native BM-MSC and their biological role in the bone marrow. DisclosuresNo relevant conflicts of interest to declare.

Influence of inflammation on the immunological profile of adult-derived human liver mesenchymal stromal cells and stellate cells

Background aimsStem cell therapy for liver diseases has recently emerged as a promising alternative to liver transplantation. Eligible cells should have an appropriate immunophenotype. The aim of the present study was to define the immunological profile of two human liver-derived mesenchymal stromal cell populations, namely, stem cells (ADHLSC) and hepatic stellate cells (HSC). MethodsThe study was conducted under normal and inflammatory conditions with the use of human bone marrow mesenchymal stromal cells (BM-MSC) as reference. ResultsLike BM-MSC and ADHLSC, HSC were negative for hematopoietic (CD45) and endothelial (CD34) markers but positive for stromal markers. All cell types were constitutively positive for HLA class I and negative for human leukocyte antigen (HLA) class II and co-stimulatory molecules (CD80, CD86, CD134 and CD252). Inflammation induced the expression of CD40 in all cell types, but the highest values were observed on HSCs; high CD252 expression was only observed on HSC as compared with ADHLSC and BM-MSC. The expression of various adhesion molecules (CD54, CD58, CD106 and CD166) was dissimilar in these three cell types and was differentially influenced by inflammation as well. ADHLSC and HSC constitutively expressed the immunosuppressive molecule HLA-G, whereas CD274 expression was induced by inflammation, as in the case of BM-MSC. Moreover, all cell types expressed the two major natural killer ligands CD112 and CD115. ConclusionsToll-like receptors (TLR) 1, 3, 4 and 6 messenger RNA was expressed by both cell types, whereas TLR 2, 5, 7, 9 and 10 were only expressed by ADHLSC. Inflammation increased the expression of TLR 2 and 3 by ADHLSC and HSC. Finally, both liver-derived cell types were immunosuppressive because they inhibited the proliferation of mitogen-activated T cells.

Current View on Osteogenic Differentiation Potential of Mesenchymal Stromal Cells Derived from Placental Tissues.

Mesenchymal stromal cells (MSC) isolated from human term placental tissues possess unique characteristics, including their peculiar immunomodulatory properties and their multilineage differentiation potential. The osteogenic differentiation capacity of placental MSC has been widely disputed, and continues to be an issue of debate. This review will briefly discuss the different MSC populations which can be obtained from different regions of human term placenta, along with their unique properties, focusing specifically on their osteogenic differentiation potential. We will present the strategies used to enhance osteogenic differentiation potential in vitro, such as through the selection of subpopulations more prone to differentiate, the modification of the components of osteo-inductive medium, and even mechanical stimulation. Accordingly, the applications of three-dimensional environments in vitro and in vivo, such as non-synthetic, polymer-based, and ceramic scaffolds, will also be discussed, along with results obtained from pre-clinical studies of placental MSC for the regeneration of bone defects and treatment of bone-related diseases.

Low/Negative Expression of PDGFR-α Identifies the Candidate Primary Mesenchymal Stromal Cells in Adult Human Bone Marrow

SummaryHuman bone marrow (BM) contains a rare population of nonhematopoietic mesenchymal stromal cells (MSCs), which are of central importance for the hematopoietic microenvironment. However, the precise phenotypic definition of these cells in adult BM has not yet been reported. In this study, we show that low/negative expression of CD140a (PDGFR-α) on lin−/CD45−/CD271+ BM cells identified a cell population with very high MSC activity, measured as fibroblastic colony-forming unit frequency and typical in vitro and in vivo stroma formation and differentiation capacities. Furthermore, these cells exhibited high levels of genes associated with mesenchymal lineages and HSC supportive function. Moreover, lin−/CD45−/CD271+/CD140alow/− cells effectively mediated the ex vivo expansion of transplantable CD34+ hematopoietic stem cells. Taken together, these data indicate that CD140a is a key negative selection marker for adult human BM-MSCs, which enables to prospectively isolate a close to pure population of candidate human adult stroma stem/progenitor cells with potent hematopoiesis-supporting capacity.

Multivariate biophysical markers predictive of mesenchymal stromal cell multipotency.

The capacity to produce therapeutically relevant quantities of multipotent mesenchymal stromal cells (MSCs) via in vitro culture is a common prerequisite for stem cell-based therapies. Although culture expanded MSCs are widely studied and considered for therapeutic applications, it has remained challenging to identify a unique set of characteristics that enables robust identification and isolation of the multipotent stem cells. New means to describe and separate this rare cell type and its downstream progenitor cells within heterogeneous cell populations will contribute significantly to basic biological understanding and can potentially improve efficacy of stem and progenitor cell-based therapies. Here, we use multivariate biophysical analysis of culture-expanded, bone marrow-derived MSCs, correlating these quantitative measures with biomolecular markers and in vitro and in vivo functionality. We find that, although no single biophysical property robustly predicts stem cell multipotency, there exists a unique and minimal set of three biophysical markers that together are predictive of multipotent subpopulations, in vitro and in vivo. Subpopulations of culture-expanded stromal cells from both adult and fetal bone marrow that exhibit sufficiently small cell diameter, low cell stiffness, and high nuclear membrane fluctuations are highly clonogenic and also exhibit gene, protein, and functional signatures of multipotency. Further, we show that high-throughput inertial microfluidics enables efficient sorting of committed osteoprogenitor cells, as distinct from these mesenchymal stem cells, in adult bone marrow. Together, these results demonstrate novel methods and markers of stemness that facilitate physical isolation, study, and therapeutic use of culture-expanded, stromal cell subpopulations.