Effects Of Mesenchymal Stromal Cells Research Articles

Effects of mesenchymal stromal cells on monocyte differentiation to M1 phenotype and M1/M2 macrophage switching

Objective. Mesenchymal stromal cells (MSCs) promote the differentiation of unprimed macrophages (Mр) or classically activated M1 cells towards alternatively activated, M2 macrophages. The aim of the work was to study the ability of MSC to induce M1→M2 switching by comparing the MSC effects on polarized M1 macrophages and monocytes stimulated by granulocyte-macrophage colony-stimulating factor to M1 differentiation. Material and мethods. MSC were co-cultured with monocytes for 7 days or M1 macrophages for 48 hours in Transwell system to prevent direct cell-to-cell contacts. To characterize generated Mр, classical M2 marker CD206, allostimulatory activity in a mixed lymphocyte culture (MLC), and the ability to secrete pro-/antiinflammatory mediators were analyzed. Results. Co-cultivation of MSCs and M1 macrophages led to the appearance of phenotypic (increased expression of CD206) and functional (decrease in allostimulatory activity) features of M2 phenotype. When MSCs were cultured with monocytes in the M1-inducing medium, generated Mр elicited a pronounced stimulating activity in MLC similar to that of M1 (stimulation index 3.45 and 3.4, p = 0.46) and significantly higher than allostimulatory activity of M2 cells (3.45 vs 2.2, p = 0.03). In addition, MSCs did not influence the expression of CD206, as well as the production of pro- (IL-1β, TNF-α, IL-6, IL-12) and anti-inflammatory (IL1-ra, IL-4, IL-10) cytokines, immunoregulatory cytokines (IFN-γ, IL-17) and chemokines (IP-10, MCP-1, MIP-1b, Rantes, Eotaxin). Conclusions: The ability of MSC to induce the M2 phenotype depends on the stage of differentiation of monocyte/macrophages. MSCs promote M1→M2 switching in cultures of polarized M1 macrophages. In contrast, when MSCs interacted with monocytes in M1-inducing medium, a population of M1-like macrophages is formed with high allostimulatory activity and typical for M1 spectrum of produced cytokines and chemokines.

Bone marrow mesenchymal stromal cells protect allograft lung transplants from acute rejection via the PD-L1/IL-17A axis.

Using a rat model of allograft lung transplantation, we investigated the effectiveness of mesenchymal stromal cells (MSCs) as prophylactic and therapeutic agents against the acute rejection of lung grafts. Lung grafts were harvested from donor rats and transplanted orthotopically into major histocompatibility complex-mismatched rats. MSCs were administered to the recipients once (on day 0) or twice (on days 0 and 3) after transplantation. The grade of acute rejection was evaluated both macroscopically and microscopically 6days after transplantation. To elucidate the related mechanism, mRNA levels of inflammatory cytokines and immunomodulatory receptors in the transplanted grafts were measured using quantitative RT-PCR. The lung graft tissue from the rats that received MSCs post-surgically was protected from acute rejection significantly better than that from the untreated controls. Notably, the rats administered MSCs twice after surgery exhibited the least signs of rejection, with a markedly upregulated mRNA level of PD-L1 and a downregulated mRNA level of IL-17A. This study assessed MSC protection of lung allografts from acute rejection by modulating T cell activity via enforced expression of PD-L1 in transplants and downregulation of IL-17A.

Suppressive effect of mesenchymal stromal cells on interferon-γ-producing capability of spleen cells was specifically enhanced through humoral mediator(s) from mouse oral squamous cell carcinoma Sq-1979 Cells In Vitro

Aim: The aim of this study was to compare the immunomodulatory effects in the tumor milieu of mouse oral squamous cell carcinoma (OSCC) cells harboring primary and advanced phenotypes. We established an in vitro co-culture system using mouse OSCC cells, spleen cells, and mesenchymal stromal cells. Methods: Sq-1979 is an OSCC cell line derived from C3H mice; 233-11 cells were established from a primary Sq-1979 tumor; L3–5, L5–11, and L6–8 cells were established from lymph node-metastasized Sq-1979 cells. 10T1/2 is a fibroblast line derived from C3H mice. The OSCC cells were co-cultured with anti-CD3 antibody-stimulated mouse spleen cells in the presence or absence of 10T1/2 cells, and the producing capability of interferon (IFN)-γ and interleukin (IL)-10 was evaluated using enzyme-linked immunosorbent assay. Results: The production of IFN-γ by the stimulated spleen cells was specifically enhanced in the presence of co-cultured L-cells. The production of IL-10 was conversely reduced in the co-culture with all the OSCC cell lines used. The production of IFN-γ was significantly reduced in the co-culture with directly contacted 10T1/2 cells, and further reduction was observed in the presence of Sq-1979 and 233-11 cells but remained unchanged in the presence of L-cells. The reduction of IFN-γ production was also observed by the addition of conditioned medium from the Sq-1979-1 cells. Conclusion: Sq-1979 cells specifically enhanced the immune-suppressive activity of mesenchymal stromal cells through humoral factor (s).

Activation of NK Cells in Mixed Cultures of Wharton's Jelly Mesenchymal Stromal Cells and Peripheral Blood Lymphocytes.

Mesenchymal stromal cells possess immunosuppressive properties that might be used for the therapy of inflammatory diseases of various geneses. The effects of mesenchymal stromal cells depend on their lifetime in the recipient tissues. During heterologous transplantation, mesenchymal stromal cells are eliminated by NK cells. We studied NK cell formation in mixed cultures of Wharton's jelly mesenchymal stromal cells and peripheral blood lymphocytes from an autologous donor. Lymphocytes were activated by a mitogen or IL-2. The lifetime of mesenchymal stromal cells was estimated by MTT test. Cytotoxic activity and phenotype of NK cells were evaluated by flow cytometry. It was found that activation of NK cells depended on IL-2 and was registered on day 2 of incubation with IL-2. In cultures with mitogen-activated lymphocytes, cytotoxicity was observed after 5-6 days. Cytotoxicity of NK correlated with significant decrease in CD16+ and increase in CD56+ NK and with reduction of mesenchymal stromal cell viability. Thus, the main mechanism of elimination of mesenchymal stromal cells is cytotoxicity of NK cells that depended on IL-2 production.

Mesenchymal stromal cells improve human islet function through released products and extracellular matrix.

The aims of the present study were (i) to determine whether the reported beneficial effects of mesenchymal stromal cells (MSCs) on mouse islet function extend to clinically relevant human tissues (islets and MSCs), enabling translation into improved protocols for clinical human islet transplantation; and (ii) to identify possible mechanisms through which human MSCs influence human islet function. Human islets were co-cultured with human adipose tissue-derived MSCs (hASCs) or pre-treated with its products - extracellular matrix (ECM) and annexin A1 (ANXA1). Mouse islets were pre-treated with mouse MSC-derived ECM. Islet insulin secretory function was assessed in vitro by radioimmunoassay. Quantitative RT-PCR was used to screen human adipMSCs for potential ligands of human islet G-protein-coupled receptors. We show that co-culture with hASCs improves human islet secretory function in vitro, as measured by glucose-stimulated insulin secretion, confirming previous reports using rodent tissues. Furthermore, we demonstrate that these beneficial effects on islet function can be partly attributed to the MSC-derived products ECM and ANXA1. Our results suggest that hASCs have the potential to improve the quality of human islets isolated for transplantation therapy of Type 1 diabetes. Furthermore, it may be possible to achieve improvements in human islet quality in a cell-free culture system by using the MSC-derived products ANXA1 and ECM.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles Provide Long-Term Survival After Total Body Irradiation Without Additional Hematopoietic Stem Cell Support

The therapeutic effect of mesenchymal stromal cells (MSC) in tissue regeneration is based mainly on the secretion of bioactive molecules. Here, we report that the radioprotective effect of mouse bone marrow derived mesenchymal stromal cells (mMSC) can be attributed to extracellular vesicles (EV) released from mMSC. The transplantation of mMSC-derived EV into lethally irradiated mice resulted in long-term survival but no improvement in short-term reconstitution of the recipients. Importantly, the radiation rescue was efficient without additional hematopoietic support. In vitro we show a protection by EV of irradiated hematopoietic stem cells but not progenitor cells using stroma-cell cultures and colony-forming assays. After systemic infusion into lethally irradiated recipients, labeled EV traveled freely through the body reaching the bone marrow within 2 hours. We further show that long-term repopulating Sca-1 positive and c-kit low-positive stem cells were directly targeted by EV leading to long-term survival. Collectively, our data suggest EV as an effective first-line treatment to combat radiation-induced hematopoietic failure which might also be helpful in alleviating myelosuppression due to chemotherapy and toxic drug reaction. We suggest the infusion of MSC-derived EV as efficient and immediate treatment option after irradiation injuries. Stem Cells 2017;35:2379-2389.

Mesenchymal stromal cell therapy reduces lung inflammation and vascular remodeling and improves hemodynamics in experimental pulmonary arterial hypertension

BackgroundExperimental research has reported beneficial effects of mesenchymal stromal cell (MSC) therapy in pulmonary arterial hypertension (PAH). However, these studies either were based on prophylactic protocols or assessed basic remodeling features without evaluating possible mechanisms. We analyzed the effects of MSC therapy on lung vascular remodeling and hemodynamics and its possible mechanisms of action in monocrotaline (MCT)-induced PAH.MethodsTwenty-eight Wistar rats were randomly divided into two groups. In the PAH group, animals received MCT 60 mg/kg intraperitoneally, while a control group received saline (SAL) instead. On day 14, both groups were further randomized to receive 105 adipose-derived MSCs or SAL intravenously (n = 7/group). On day 28, right ventricular systolic pressure (RVSP) and the gene expression of mediators associated with apoptosis, inflammation, fibrosis, Smad-1 levels, cell proliferation, and endothelial–mesenchymal transition were determined. In addition, lung histology (smooth muscle cell proliferation and plexiform-like injuries), CD68+ and CD163+ macrophages, and plasma levels of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) were evaluated.ResultsIn the PAH group, adipose-derived MSCs, compared to SAL, reduced mean RVSP (29 ± 1 vs 39 ± 2 mmHg, p < 0.001), lung tissue collagen fiber content, smooth muscle cell proliferation, CD68+ macrophages, interleukin-6 expression, and the antiapoptotic mediators Bcl-2 and survivin. Conversely, expression of the proapoptotic mediator procaspase-3 and plasma VEGF increased, with no changes in PDGF. In the pulmonary artery, MSCs dampened the endothelial–mesenchymal transition.ConclusionIn MCT-induced PAH, MSC therapy reduced lung vascular remodeling, thus improving hemodynamics. These beneficial effects were associated with increased levels of proapoptotic markers, mesenchymal-to-endothelial transition, reduced cell proliferation markers, and inflammation due to a shift away from the M1 phenotype.

Proliferation of Peripheral Blood Lymphocytes and Mesenchymal Stromal Cells Derived from Wharton's Jelly in Mixed and Membrane-Separated Cultures.

We studied the effect of mesenchymal stromal cells on proliferation of CFSE-stained T cells in mixed and membrane-separated (Transwell) cultures and in 3D culture of mesenchymal stromal cells from Wharton's jelly. The interaction of mesenchymal stromal cells with mitogen-activated peripheral blood lymphocytes from an allogeneic donor was followed by suppression of T-cell proliferation in a wide range of cell proportions. Culturing in the Transwell system showed the absence of suppression assessed by the fraction of proliferating cells and by the cell cycle analysis. In 3D cultures, contact interaction of mesenchymal stromal cells and lymphocytes was demonstrated that led to accumulation of G2/M phase lymphocytes and G0/G1 phase mesenchymal stromal cells. The suppressive effect of mesenchymal stromal cells from Wharton's jelly is mediated by two mechanisms. The effects are realized within 6 days, which suggests that the therapeutic effects of mesenchymal stromal cells persist until their complete elimination from the body.

Ameliorative Effect of Mesenchymal Stromal Cells on Diabetic Nephropathy in Male Rats

Ameliorative Effect of Mesenchymal Stromal Cells on Diabetic Nephropathy in Male Rats

Ameliorative Effect of Mesenchymal Stromal Cells on Diabetic Nephropathy in Male Rats

Both types of diabetes mellitus (DM) are recognized by the destruction of pancreas or deficient function of Islets’ cells causing several complications. Diabetes mainly affect the kidney leading to diabetic nephropathy (DN) in the late renal stage, which caused higher mortality in diabetic patients. Since diabetic disease appearance, nephropathy may be observed in patients with type 1 or 2 diabetes. Recently, cell culture can be used in the regenerative medicine as a new method for treating diabetes and DN. Therefore, the aim of the current study was to prove the beneficial effect of mesenchymal stromal cells (MSCs) transplantation on DN during the early stage. Male rats were randomized in 3 groups (each 20 rats): the 1st group was normal rats, while the 2 nd was streptozotocin (STZ) diabetic rats and the 3 rd was diabetic rats treated with a single intravenous dose of bone marrow mesenchymal stromal cells (BM-MSCs) after 3 days from STZ induction. Results indicated that STZ induced DN represented by weight loss, hyperglycemia, hypoinsulineamia, decreased glycated hemoglobin, leukocytosis and impairment of kidney function and oxidative stress in kidney tissue. After BM-MSCs treatment, blood glucose level was improved, renal function was retained, body weight loss was decreased, insulin level and HBA1C percent were ameliorated with improved oxidative stress in kidney tissue. BM-MSCs have the capacity to regenerate and differentiate into insulin- producing cells improving DM and DN.

Paracrine Effects of Mesenchymal Stromal Cells Cultured in Three-Dimensional Settings on Tissue Repair.

Mesenchymal stromal cells (MSCs) are a promising cell source for promoting tissue repair, due to their ability to release growth, angiogenic, and immunomodulatory factors. However, when injected as a suspension, these cells suffer from poor survival and localization, and suboptimal release of paracrine factors. While there have been attempts to overcome these limitations by modifying MSCs themselves, a more versatile solution is to grow them in three dimensions, as aggregates or embedded into biomaterials. Here we review the mechanisms by which 3D culture can influence the regenerative capacity of undifferentiated MSCs, focusing on recent examples from the literature. We further discuss how knowledge of these mechanisms can lead to strategic design of MSC therapies that overcome some of the challenges to their effective translation.

Cytokine Production in Mixed Cultures of Mesenchymal Stromal Cells from Wharton's Jelly and Peripheral Blood Lymphocytes.

We compared the production of 19 humoral factors in mixed cultures of mesenchymal stromal cells from Wharton's jelly and allogenic peripheral blood lymphocytes. For evaluation of the specificity of immunosuppressive activity of mesenchymal stromal cells, comparative analysis of the production of these humoral factors in mixed cultures of lymphocytes and epithelial BxPC-3 cells was conducted. The production of soluble factors in both mono- and mixed cultures significantly correlated (p<0.05). The maximum production was found for proinflammatory chemokine IP-10 and IFN-γ and anti-inflammatory cytokine IL-10. The major difference of mesenchymal stromal cells from epithelial BxPC-3 cells was 7-fold higher production of IL-10, which can explain the immunosuppressive effect of mesenchymal stromal cells.

Left Ventricular Dysfunction Switches Mesenchymal Stromal Cells Toward an Inflammatory Phenotype and Impairs Their Reparative Properties Via Toll-Like Receptor-4.

Little is known about the potentially unfavorable effects of mesenchymal stromal cell (MSC) activation on the heart. MSCs can respond to tissue injury by anti- or proinflammatory activation. We aimed to study the potential negative interaction between left ventricular dysfunction (LVD) and MSC activation. We isolated MSCs from cardiac and subcutaneous fat tissues of mice with LVD 28 days after myocardial infarction or sham operation. To evaluate the effect of LVD on MSCs, we characterized cardiac MSCs and subcutaneous MSCs in vitro. Subsequently, we injected MSCs or saline into the infarcted myocardium of mice and evaluated LV remodeling and function 28 days after myocardial infarction. To test the hypothesis that toll-like receptor 4 (TLR4) mediates proinflammatory polarization of MSCs, we characterized cardiac MSCs from TLR4-/- and wild-type (WT) mice after inflammatory stimulation in vitro. Next, we transplanted cardiac MSCs from TLR4-/- and WT male mice into the infarcted myocardium of female WT mice and evaluated infarct size, MSC retention, inflammation, remodeling, and function after 7 days. LVD switched cardiac MSCs toward an inflammatory phenotype, with increased secretion of inflammatory cytokines as well as chemokines. The effect of LVD on subcutaneous MSCs was less remarkable. Although transplantation of cardiac MSCs and subcutaneous MSCs from LVD and sham hearts did not improve LV remodeling and function, cardiac MSCs from LVD exacerbated anterior wall thinning 28 days after myocardial infarction. The inflammatory polarization of cardiac MSCs by LVD was mediated by TLR4, as we found less secretion of inflammatory cytokines and higher secretion of anti-inflammatory cytokines from activated cardiac MSCs of TLR4-deficient mice, compared with WT cardiac MSCs. Significantly, TLR4 deficiency preserved the expression of CD47 (don't eat me signal) on cardiac MSCs after both TLR4 stimulation in vitro and transplantation into the infarcted heart. Compared with WT cardiac MSCs and saline, TLR4-/- cardiac MSCs survived in the cardiac tissue and maintained their reparative properties, reduced infarct size, increased scar thickness, and attenuated LV dilatation 7 days after myocardial infarction. The environment of the failing and infarcted myocardium drives resident and transplanted MSCs toward a proinflammatory phenotype and restricts their survival and reparative effects in a mechanism mediated by TLR4.

Hypoxia-Induced Mesenchymal Stromal Cells Exhibit an Enhanced Therapeutic Effect on Radiation-Induced Lung Injury in Mice due to an Increased Proliferation Potential and Enhanced Antioxidant Ability

Background/Aims: Radiation therapy is an important treatment for thoracic cancer; however, side effects accompanied with radiotherapy lead to limited tumor control and a decline in patient quality of life. Among these side effects, radiation-induced lung injury (RILI) is the most serious and common. Hence, an effective remedy for RILI is needed. Mesenchymal stromal cells (MSCs) are multipotent adult stem cells that have been demonstrated to be an effective treatment in some disease caused by tissue damage. However, unlike other injuries, RILI received limited therapeutic effects from implanted MSCs due to local hypoxia and extensive reactive oxygen species (ROS) in irradiated lungs. Since the poor survival of MSCs is primarily due to hypoxia and ROS generation, we hypothesize that persistent and adaptive hypoxia treatment induces enhanced resistance to hypoxic stress in implanted MSC. The aim of this study is to investigate whether persistent and adaptive hypoxia treatment of bmMSCs prior to their transplantation in injured mice enhanced survival and improved curative effects in RILI. Methods: Primary bmMSCs were obtained from the marrow of six-week-old male C57BL6/J mice and were cultured either under normoxic conditions (21% O₂) or hypoxic conditions (2.5% O₂). Mice were injected with normoxia/hypoxia MSCs after thoracic irradiation (20 Gy). The therapeutic effects of MSCs on RILI were assessed by pathological examinations that included H&E staining, Masson staining and α-SMA staining; meanwhile, inflammatory factors were measured using an ELISA. The morphology of MSCs in vitro was recorded using a microscope and identified by flow cytometry, cell viability was measured using the CCK-8 assay, the potential for proliferation was detected by the EdU assay, and ROS levels were measured using a ROS fluorogenic probe. In addition, HIF-1α and several survival pathway proteins (Akt, p-Akt, Caspase-3) were also detected by western blotting. Results: Implanted MSCs alleviated both early radiation-induced pneumonia and late pulmonary fibrosis. However, hypoxia MSCs displayed a more pronounced therapeutic effect compared to normoxia MSCs. Compared to normoxia MSCs, the hypoxia MSCs demonstrated greater cell viability, an enhanced proliferation potential, decreased ROS levels and increased resistance to hypoxia and ROS stress. In addition, hypoxia MSCs achieved higher activation levels of HIF-1α and Akt, and HIF-1α played a critical role in the development of resistance. Conclusion: Hypoxia enhances the therapeutic effect of mesenchymal stromal cells on radiation-induced lung injury by promoting MSC proliferation and improving their antioxidant ability, mediated by HIF-1α.

Effects of Mesenchymal Stromal Cells on the Neuropathic Pain Induced by Chronic Constriction Injury in Rats

Background: Neuropathic pain remains a persistent clinical problem and characterized by mechanical allodynia and heat hyperalgesia. Chronic pain conditions are among the major health problems which are difficult to treat. Bone marrow-derived mesenchymal stromal cells (BMSCs) have generated great interest as an option for cell-based therapy. BMSCs are easy to isolate and expand ex vivo. Clinical studies show that direct injection of BMSCs does not produce side effects as rejection and is well tolerated by the immune system. Methods: Neuropathic pain model in rats was developed with the ligation of the sciatic nerve. BMSCs were isolated from femur and tibia aspirates of rats and kept in culture media. rBMSCs were injected locally into injured sciatic nerve area of rats and efficiency of the therapy was observed with thermal sensitivity and motor functions for 4 weeks after injection of rBMSCs. Results: After injection into injured area rBMSCs were located in sciatic nerve tissue. In the present study, we showed that a single systemic local injection (into the lesion site) of rBMSCs reversed pain hypersensitivity in rats after injury and decreased the pain symptoms for 2 weeks and these effects got back in 4 weeks. Discussion: Our results revealed that single injection of rBMSCs showed relief of pain in short-term follow-up and further booster injection needed for long term prolonged therapeutic approach.

Mesenchymal stromal cells support the viability and differentiation of thymocytes through direct contact in autologous co-cultures.

The development of thymocytes and generation of mature T cells is a complex process that requires spatio-temporal interactions of thymocytes with the other cells of the thymus microenvironment. Recently, mesenchymal stromal cells were isolated from the neonatal human thymus and differentiated into chondrogenic, osteogenic, and adipogenic lineages, just like their bone marrow counterparts. However, their function in thymocyte homeostasis is unknown. In our autologous co-cultures of rat mesenchymal stromal cells and thymocytes, the stromal cells preserve the viability of cultured thymocytes and stimulate the development of CD4-CD8- double-negative and the maturation of mainly CD4+ single-positive thymocytes. Thymocytes also influence the stemness of bone marrow mesenchymal stromal cells, as their expression of CD44, a marker associated with cellular proliferation and migration, is reduced in co-cultures. Mesenchymal stromal cells' influence on thymocyte development requires direct physical contact between the two cells and is not mediated by a soluble factor. When the two types of cells were physically separated, the stimulative effects of mesenchymal stromal cells on thymocytes did not occur. Electron microscopy confirmed the close contact between the membranes of thymocytes and mesenchymal stromal cells. Our experiments suggest that membrane exchanges could occur between mesenchymal stromal cells and thymocytes, such as the transfer of CD44 from mesenchymal stromal cells to the thymocytes, but its functional significance for thymocytes development remains to be established. These results suggest that mesenchymal stromal cells could normally be a part of the in vivo thymic microenvironment and form a niche that could sustain and guide the development of thymocytes.

Effects of mesenchymal stromal cells on human myeloid dendritic cell differentiation and maturation in a humanized mouse model

Mesenchymal stromal cells (MSCs) have shown promise as cellular therapy in allogeneic transplantation, although the precise mechanisms underlying their benefit in clinical trials are difficult to study. We previously demonstrated that MSCs exert immunoregulatory effects in mouse bone marrow-derived dendritic cell (DC) culture. Since mouse studies do not reliably reproduce human events, we used a humanized mouse model to study the immunomodulatory effects of human MSCs on human DC immunobiology. Humanized mice were established by injection of cord blood CD34+ cells into NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NOD scid gamma, NSG) mice. Human cells were detected in the mouse bone marrow, blood, and spleen 12weeks after transplantation. Human DCs were differentiated from humanized mouse bone marrow cells during human MSC co-culture. MSCs inhibited DC differentiation and kept DCs in an immature state as demonstrated by phenotype and function. In conclusion, humanized mouse models represent a useful method to study the function of human MSCs on human DC immunobiology.

A New Hypothesis: The Immunomodulatory Effects of Mesenchymal Stromal Cell Derived Extracellular Vesicles in Ischemic Kidney Injury Partly through Spleen

A New Hypothesis: The Immunomodulatory Effects of Mesenchymal Stromal Cell Derived Extracellular Vesicles in Ischemic Kidney Injury Partly through Spleen

Small intestinal submucosa-derived extracellular matrix bioscaffold significantly enhances angiogenic factor secretion from human mesenchymal stromal cells

IntroductionThe in vivo therapeutic effect of mesenchymal stromal cells (MSCs) is currently believed to be tightly linked to their paracrine secretion ability. However, insufficient or imprecise cell delivery, low cell survival and retention post-transplant, along with harsh donor site microenvironments, are major barriers to the clinical success of MSC therapies. Here we tested a small intestinal submucosa (SIS)-derived extracellular matrix (ECM) bioscaffold augmented with MSCs, with the hypothesis that they will facilitate the precise delivery of increased numbers of MSCs therefore improving cell viability and retention.MethodsIn this study, we evaluated the secretion of angiogenic factors from three human MSC lines cultured on SIS ECM. We used human antibody array and enzyme-linked immunosorbent assay to measure the level of angiogenic factors released from MSCs when cultured on SIS ECM or regular tissue culture plastic. We tested MSCs cultured for three different time points.ResultsWe found that the SIS ECM culture environment can significantly enhance the release of several angiogenic factors when compared to MSCs cultured on standard tissue culture plastic. Specifically, vascular endothelial growth factor and interleukin-8 secretion was significantly increased at 24, 48 and 72 hours postseeding onto SIS ECM whereas vascular endothelial growth factor release for cells cultured on plastic surface remained the same during these time points. We also observed significant donor to donor variation in cytokine production.ConclusionsThis study demonstrates that MSCs transplanted onto a SIS ECM may greatly increase their therapeutic potential through an increase in pro-angiogenic cytokine release.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0165-3) contains supplementary material, which is available to authorized users.

In Vivo Effects of Mesenchymal Stromal Cells in Two Patients With Severe Acute Respiratory Distress Syndrome

Mesenchymal stromal cells (MSCs) have been investigated as a treatment for various inflammatory diseases because of their immunomodulatory and reparative properties. However, many basic questions concerning their mechanisms of action after systemic infusion remain unanswered. We performed a detailed analysis of the immunomodulatory properties and proteomic profile of MSCs systemically administered to two patients with severe refractory acute respiratory distress syndrome (ARDS) on a compassionate use basis and attempted to correlate these with in vivo anti-inflammatory actions. Both patients received 2×10(6) cells per kilogram, and each subsequently improved with resolution of respiratory, hemodynamic, and multiorgan failure. In parallel, a decrease was seen in multiple pulmonary and systemic markers of inflammation, including epithelial apoptosis, alveolar-capillary fluid leakage, and proinflammatory cytokines, microRNAs, and chemokines. In vitro studies of the MSCs demonstrated a broad anti-inflammatory capacity, including suppression of T-cell responses and induction of regulatory phenotypes in T cells, monocytes, and neutrophils. Some of these in vitro potency assessments correlated with, and were relevant to, the observed in vivo actions. These experiences highlight both the mechanistic information that can be gained from clinical experience and the value of correlating in vitro potency assessments with clinical effects. The findings also suggest, but do not prove, a beneficial effect of lung protective strategies using adoptively transferred MSCs in ARDS. Appropriate randomized clinical trials are required to further assess any potential clinical efficacy and investigate the effects on in vivo inflammation. This article describes the cases of two patients with severe refractory adult respiratory syndrome (ARDS) who failed to improve after both standard life support measures, including mechanical ventilation, and additional measures, including extracorporeal ventilation (i.e., in a heart-lung machine). Unlike acute forms of ARDS (such in the current NIH-sponsored study of mesenchymal stromal cells in ARDS), recovery does not generally occur in such patients.