Cryopreserved mesenchymal stromal cell treatment is safe and feasible for severe dilated ischemic cardiomyopathy

Background aimsBone marrow (BM) mesenchymal stromal cells (MSC) represent a novel therapy for severe heart failure with extensive myocardial scarring, especially when performed concurrently with conventional revascularization. However, stem cells are difficult to transport in culture media without risk of contamination, infection and reduced viability. We tested the feasibility and safety of off-site MSC culture and expansion with freeze-controlled cryopreservation and subsequent rapid thawing of cells immediately prior to implantation to treat severe dilated ischemic cardiomyopathy.MethodsWe recruited three consecutive patients with end-stage ischemic heart failure with evidence of full-thickness myocardial scarring. MSC was isolated from 20 mL BM aspiration, expanded and cryopreserved using 10% dimethyl sulfoxide (DMSO). Cells were transported in a cryoshipper. Patients underwent concurrent coronary artery bypass graft (CABG) with intramyocardial MSC injection.ResultsThe cell viability after thawing exceeded 90% for all samples. The supernatant was free from bacterial and fungal growth. All patients underwent the procedure safely. There were no arrhythmias noted. There was significant improvement in cardiac function and volume, resolution of scarring and increased wall thickness for all patients on cardiac magnetic resonance imaging at 6 months compared with baseline. The magnitude of improvement was more than was expected with CABG alone. Patients remained well at 1 year.ConclusionsRate-controlled freezing with 10% DMSO is a safe, feasible and practical method of cryopreserving MSC for cell storage and transportation without risk of contamination or cell death. Direct MSC injection may be beneficial as an adjunct to cardiac revascularization.     

Mesenchymal stromal cells inhibit graft-versus-host disease of mice in a dose-dependent manner

Background aimsGraft-versus-host disease (GvHD) remains a major complication after allogeneic hematopoietic cell transplantation (HCT). Recent literature demonstrates a potential benefit of human mesenchymal stromal cells (MSC) for the treatment of refractory GvHD; however, the optimal dose remains uncertain. We set out to develop an animal model that can be used to study the effect of MSC on GvHD.MethodsA GvHD mouse model was established by transplanting C3H/he donor bone marrow (BM) cells and spleen cells into lethally irradiated BALB/c recipient mice. MSC were obtained from C3H/he mice and the C3H/10T1/2 murine MSC line.ResultsThe mRNA expression of Foxp3 in regional lymph nodes (LN) localized with T cells was markedly increased by the addition of C3H10T1/2 cells in a real-time polymerase chain reaction (PCR). Using a mixed lymphocyte reaction, we determined the optimal splenocyte proliferation inhibition dose (MSC:splenocyte ratios 1:2 and 1:1). Three different C3H10T1/2 cell doses (low, 0.5 × 10⁶, intermediate, 1 × 10⁶, and high, 2 × 10⁶) with a consistent splenocyte dose (1 × 10⁶) were evaluated for their therapeutic potential in an in vivo GvHD model. The clinical and histologic GvHD score and Kaplan–Meier survival rate were improved after MSC transplantation, and these results demonstrated a dose-dependent inhibition.ConclusionsWe conclude that MSC inhibit GvHD in a dose-dependent manner in this mouse model and this model can be used to study the effects of MSC on GvHD.     

A regenerative approach for bone repair in congenital pseudarthrosis of the tibia associated or not associated with type 1 neurofibromatosis: correlation between laboratory findings and clinical outcome

Background and aimsCongenital pseudarthrosis of the tibia (CPT) is a rare orthopedic disease presenting spontaneous fractures that do not heal. The treatment of CPT is characterized by repeated surgical procedures that often fail, with the inevitable outcome of severe disability and amputation. We tested the hypothesis that CPT may benefit from regenerative strategies based on mesenchymal stromal cells (MSC) combined with platelet-rich fibrin (PRF) as a source of growth factors. The aim of the study was to verify whether laboratory testing to assess the osteogenic properties of MSC and the osteo-inductive activity of PRF correlated with the clinical outcome.MethodsTen patients affected by refractory CPT were treated by using MSC derived from the iliac crest (IC-MSC), PRF and lyophilized bone. In six patients, CPT was associated with type 1 neurofibromatosis (NF1). Biochemical, functional and molecular assays were performed to assess the intrinsic osteogenic potential of IC-MSC (cells cultured with fetal calf serum) and the osteo-inductive properties of PRF (cells cultured with autologous serum).ResultsBone consolidation was obtained in three patients who had CPT and NF1. In these patients, the IC-MSC exposed to autologous serum were able to form mineral nodules in vitro, while the mineralizing ability was totally abrogated in patients with a poor clinical outcome.ConclusionsCell therapy may be a useful tool for the treatment of refractory CPT because it increases the opportunity to achieve effective bone tissue regeneration. Our data suggest that the presence of pro-osteogenic growth factors is an essential requirement for bone healing.     

Human umbilical cord provides a significant source of unexpanded mesenchymal stromal cells

Background aimsHuman mesenchymal stromal cells (MSC) have considerable potential for cell-based therapies, including applications for regenerative medicine and immune suppression in graft-versus-host disease (GvHD). However, harvesting cells from the human body can cause iatrogenic disorders and in vitro expansion of MSC carries a risk of tumorigenesis and/or expansion of unexpected cell populationsMethodsGiven these problems, we have focused on umbilical cord, a tissue obtained with few ethical problems that contains significant numbers of MSC. We have developed a modified method to isolate MSC from umbilical cord, and investigated their properties using flow cytometry, mRNA analysis and an in vivo GvHD modelResultsOur study demonstrates that, using umbilical cord, large numbers of MSC can be safely obtained using a simple procedure without in vitro expansion, and these non-expanded MSC have the potential to suppress GvHD.ConclusionsOur results suggest that the combined banking of umbilical cord-derived MSC and identical cord blood-derived hematopoietic stem cell banking, where strict inspection of the infectious disease status of donors is performed, as well as further benefits of HLA-matched mesenchymal cells, could become one of the main sources of cells for cell-based therapy against various disorders.     

Intramyocardial and intracoronary autologous bone marrow-derived mesenchymal stromal cell treatment in chronic severe dilated cardiomyopathy

Background aimsMesenchymal stromal cells (MSC) may improve cardiac function following myocardial infarction. MSC can differentiate into cardiomyocytes and endothelial cells while exerting additional paracrine effects. There is limited information regarding the efficacy of route for MSC treatment of severe dilated cardiomyopathy (DCM). The aim of this study was to demonstrate the clinical safety, feasibility and efficacy of direct intramyocardial and intracoronary administration of autologous bone marrow-derived MSC treatment for no-option patients with chronic severe refractory DCM.MethodsTen symptomatic patients with DCM and refractory cardiac function, despite maximum medical therapy, were selected. Five had ischemic DCM deemed unlikely to benefit from revascularization alone and underwent bypass operations with concurrent intramyocardial MSC injection (group A). Two patients had previous revascularization and three had non-ischemic DCM and received intracoronary MSC injection (group B).ResultsGroup A and B patients received 0.5–1.0 × 10⁶ and 2.0–3.0 × 10⁶ MSC/kg body weight, respectively. All patients remained alive at 1 year. There were significant improvements from baseline to 6 and 12 months in left ventricular ejection fraction and other left ventricular parameters. Scar reduction was noted in six patients by 12 months.ConclusionsAutologous bone marrow MSC treatment is safe and feasible for treating chronic severe refractory DCM effectively, via intracoronary or direct intramyocardial administration at prescribed doses.     

Attempt to treat congenital pseudarthrosis of the tibia with mesenchymal stromal cell transplantation

Background aimsCongenital pseudarthrosis of the tibia (CPT) caused by neurofibromatosis type 1 (NF1) is a refractory disease occurring in childhood. We present two cases that had failed all earlier treatment attempts and, as a last treatment attempt, the patients were chosen to receive mesenchymal stromal cell (MSC) transplantation prior to amputation.MethodsThe MSC from bone marrow (BM) were harvested from the iliac crest and cultured in osteoinductive medium for 3 weeks. The cultured MSC were injected in solution into BM canals of the tibia and around the resection line or bone defect in a 3-dimensional collagen sponge scaffold. After the MSC transplantation, the patients were monitored during a 10-month follow-up period. In both cases, bone formation at the pseudarthrosis site was observed and two of three treated bone defects healed. For clinical reasons not related to cell transplantation, such as new infection and pseudarthrosis and severe shortening of the leg, both extremities were finally amputated and bone samples were analyzed to evaluate MSC therapy effect and safety.ResultsMSC transplantation normalized bone remodeling, promoted bone resorption and improved the overall structure of bone. The number of osteoclasts in the cortical bone was 2-fold higher compared with the monitored situation before MSC transfer. In addition, the mineral content of the bone improved after transplantation. We could see no sign of aberrant bone formation or malignant transformation.ConclusionsOur data suggest that MSC transplantation is a possibility for treatment of CPT caused by NF1 in less severe cases without adjunct defects.     

Human platelet lysate stimulates high-passage and senescent human multipotent mesenchymal stromal cell growth and rejuvenation in vitro

Background aimsMultipotent mesenchymal stromal cells (MSCs) are clinically useful because of their immunomodulatory and regenerative properties, but MSC therapies are limited by the loss of self-renewal and cell plasticity associated with ex vivo expansion culture and, on transplantation, increased immunogenicity from xenogen exposure during culture. Recently, pooled human platelet lysate (hPL) has been used as a culture supplement to promote MSC growth; however, the effects of hPL on MSCs after fetal bovine serum (FBS) exposure remain unknown.MethodsMSCs were cultured in medium containing FBS or hPL for up to 16 passages, and cell size, doubling time and immunophenotype were determined. MSC senescence was assessed by means of a fluorometric assay for endogenous β-galactosidase expression. MSCs cultured with FBS for different numbers of passages were switched to hPL conditions to evaluate the ability of hPL to “rescue” the proliferative capacity of MSCs.ResultshPL culture resulted in more rapid cell proliferation at earlier passages (passage 5 or earlier) than remove FBS; by day 4, hPL (5%) yielded an MSC doubling time of 1.28 days compared with 1.52 days in 16% FBS. MSCs cultured first in FBS and switched to hPL proliferated more and demonstrated less β-galactosidase production and smaller cell sizes than remove MSCs continuously propagated in FBS.ConclusionshPL enables rapid expansion of MSCs without adversely affecting immunophenotype. hPL culture of aged and senescent MSCs demonstrated cellular rejuvenation, reflected by decreased doubling time and smaller cell size. These results suggest that expansion of MSCs in hPL after FBS exposure can enhance cell phenotype and proliferative capacity.     

Immunophenotypic characteristics of multipotent mesenchymal stromal cells that affect the efficacy of their use in the prevention of acute graft vs host disease

BACKGROUNDMultipotent mesenchymal stromal cells (MSCs) are widely used in the clinic due to their unique properties, namely, their ability to differentiate in all mesenchymal directions and their immunomodulatory activity. Healthy donor MSCs were used to prevent the development of acute graft vs host disease (GVHD) after allogeneic bone marrow transplantation (allo-BMT). The administration of MSCs to patients was not always effective. The MSCs obtained from different donors have individual characteristics. The differences between MSC samples may affect their clinical efficacy.AIMTo study the differences between effective and ineffective MSCs.METHODSMSCs derived from the bone marrow of a hematopoietic stem cells donor were injected intravenously into allo-BMT recipients for GVHD prophylaxis at the moment of blood cell reconstitution. Aliquots of 52 MSC samples that were administered to patients were examined, and the same cells were cultured in the presence of peripheral blood mononuclear cells (PBMCs) from a third-party donor or treated with the pro-inflammatory cytokines IL-1β, IFN and TNF. Flow cytometry revealed the immunophenotype of the nontreated MSCs, the MSCs cocultured with PBMCs for 4 d and the MSCs exposed to cytokines. The proportions of CD25-, CD146-, CD69-, HLA-DR- and PD-1-positive CD4+ and CD8+ cells and the distribution of various effector and memory cell subpopulations in the PBMCs cocultured with the MSCs were also determined.RESULTSDifferences in the immunophenotypes of effective and ineffective MSCs were observed. In the effective samples, the mean fluorescence intensity (MFI) of HLA-ABC, HLA-DR, CD105, and CD146 was significantly higher. After MSCs were treated with IFN or cocultured with PBMCs, the HLA-ABC, HLA-DR, CD90 and CD54 MFI showed a stronger increase in the effective MSCs, which indicated an increase in the immunomodulatory activity of these cells. When PBMCs were cocultured with effective MSCs, the proportions of CD4+ and CD8+central memory cells significantly decreased, and the proportion of CD8+CD146+ lymphocytes increased more than in the subpopulations of lymphocytes cocultured with MSC samples that were ineffective in the prevention of GVHD; in addition, the proportion of CD8+effector memory lymphocytes decreased in the PBMCs cocultured with the effective MSC samples but increased in the PBMCs cocultured with the ineffective MSC samples. The proportion of CD4+CD146+ lymphocytes increased only when cocultured with the inefficient samples.CONCLUSIONFor the first time, differences were observed between MSC samples that were effective for GVHD prophylaxis and those that were ineffective. Thus, it was shown that the immunomodulatory activity of MSCs depends on the individual characteristics of the MSC population.     

Clinicopathologic findings following intra-articular injection of autologous and allogeneic placentally derived equine mesenchymal stem cells in horses

Background aimsThe development of an allogeneic mesenchymal stem cell (MSC) product to treat equine disorders would be useful; however, there are limited in vivo safety data for horses. We hypothesized that the injection of self (autologous) and non-self (related allogeneic or allogeneic) MSC would not elicit significant alterations in physical examination, gait or synovial fluid parameters when injected into the joints of healthy horsesMethodsSixteen healthy horses were used in this study. Group 1 consisted of foals (n = 6), group 2 consisted of their dams (n = 5) and group 3 consisted of half-siblings (n = 5) to group 1 foals. Prior to injection, MSC were phenotyped. Placentally derived MSC were injected into contralateral joints and MSC diluent was injected into a separate joint (control). An examination, including lameness evaluation and synovial fluid analysis, was performed at 0, 24, 48 and 72 h post-injectionResultsMSC were major histocompatibility complex (MHC) I positive, MHC II negative and CD86 negative. Injection of allogeneic MSC did not elicit a systemic response. Local responses such as joint swelling or lameness were minimal and variable. Intra-articular MSC injection elicited marked inflammation within the synovial fluid (as measured by nucleated cell count, neutrophil number and total protein concentration). However, there were no significant differences between the degree and type of inflammation elicited by self and non-self-MSCConclusionsThe healthy equine joint responds similarly to a single intra-articular injection of autologous and allogeneic MSC. This pre-clinical safety study is an important first step in the development of equine allogeneic stem cell therapies.     

血必净联合利奈唑胺注射液对老年重症肺炎患者血清肺表面活性蛋白、基质金属蛋白酶及其组织抑制剂水平的影响

目的:探讨血必净联合利奈唑胺注射液治疗老年重症肺炎患者的临床疗效及对患者血清肺表面活性蛋白(Pulmonary surfactant protein,SP)、基质金属蛋白酶(Matrix metalloproteinases,MMPs)及其组织抑制剂(Matrix metalloproteinases tissue inhibitor,TIMPs)水平的影响。方法:选择我院2015年6月～2017年12月收治的101例老年重症肺炎患者,按随机数字表法分为对照组(n=48)和研究组(n=53)。对照组采用利奈唑胺注射液治疗,研究组在对照组基础上采用血必净治疗。比较两组临床疗效,细菌清除情况,症状缓解时间,治疗前后血清SP、MMPs、TIMPs水平的变化,动脉血气,肺功能,不良反应的发生情况和28天内病死率。结果:治疗后,研究组有效率、细菌清除率均显著高于对照组(均P0.05),发热消失、血常规恢复、痰液颜色改变及胸部影像明显吸收时间均明显短于对照组(P0.05);两组血清SP-A、SP-B、SP-C、SP-D、MMP-2、MMP-9及TIMP-1及TIMP-2、血氧饱和度(blood oxygen saturation,SaO_2)、动脉血二氧化碳分压(arterial blood,PaCO_2)、动脉血二氧化碳分压(arterial blood CO_2 partial pressure of CO_2 partial pressure,PaCO_2)、峰流速(peak velocity of flow,PEF)水平均较治疗前显著下降,而血氧饱和度(blood oxygen saturation,SaO_2)、氧分压(oxygen partial pressure,PaO2)、最大呼气中段流量(maximum tidal midexpiratory flow,MMF)、用力肺活量(forced vital capacity,FVC)均较治疗前明显上升,且研究组以上指标变化较对照组更明显(均P0.05)。两组不良反应的发生情况比较差异无统计学意义(P0.05),而研究组在28天内病死率显著低于对照组(P0.05)。结论:血必净联合利奈唑胺注射液对老年重症肺炎患者的疗效优于单用利奈唑胺注射液治疗,可能与其显著降低患者血清SP、MMPs及TIMPs水平,改善肺功能,降低病死率有关。     

Alternatives to donor matching for control of graft-versus-host disease

Graft-versus-host disease (GvHD) after bone-marrow transplantation in dogs is controlled by many different genetic systems. In littermate combinations identical for the major histocompatibility complex (MHC) the number of systems that influence GvHD is related to the number of donor lymphocytes injected. If the number of donor lymphocytes administered is sufficiently low, minor histocompatibility systems do not influence survival after bone-marrow transplantation. With increasing numbers of donor lymphocytes the beneficial influence of MHC matching on GvH incidence and severity disappears and minor histocompatibility antigens, coded for on at least two other autosomal chromosomes as well as possibly the Y chromosome, can cause severe GvHD. In contrast, the X chromosome does not appear to carry a histocompatibility system that is of relevance to GvHD control. The severity and tissue distribution of histological signs of GvHD in recipients of bone-marrow and lymph-node cells from MHC-identical donors are similar to those in recipients of MHC-mismatched bone-marrow cells. Female donors do appear to cause severe GvHD more frequently than males. In contrast to rhesus monkey and human bone-marrow cells, dog bone-marrow cells are negative in PHA tests. This is in accordance with the generally benign course of GvHD in dogs that are treated with bone-marrow cells only from histocompatible littermate donors. The influence of the sex of the bone-marrow donor on GvHD incidence and severity is not reflected in differences between PHA tests with male and female dog lymphocytes. A better predictive test for GvH potential than the PHA test appears to be needed. Alternatives to additional donor selection for the prevention of GvHD in histocompatible recipients appear to be the use of a male donor and the removal of lymphocytes from bone-marrow-cell suspensions prior to transplantation.     

Impact of individual platelet lysates on isolation and growth of human mesenchymal stromal cells

Background aimsCulture medium for mesenchymal stromal cells (MSC) is frequently supplemented with fetal calf serum (FCS). FCS can induce xenogeneic immune reactions, transmit bovine pathogens and has a high lot-to-lot variability that hampers reproducibility of results. Several studies have demonstrated that pooled human platelet lysate (HPL) provides an attractive alternative for FCS. However, little is known about the variation between different platelet lysates.MethodsWe compared activities of individual HPL on initial fibroblastoid colony-forming units (CFU-F), proliferation, in vitro differentiation and long-term culture. These data were correlated with chemokine profiles of HPL.ResultsIsolation of MSC with either HPL or FCS resulted in similar CFU-F frequency, colony morphology, immunophenotype and adipogenic differentiation potential. Osteogenic differentiation was even more pronounced in HPL than FCS. There were significant differences in MSC proliferation with different HPL, but it was always higher in comparison with FCS. Cell growth correlated with the concentration of platelet-derived growth factor (PDGF) and there was a moderate association with platelet counts. All HPL facilitated expansion for more than 20 population doublings.ConclusionsTaken together, reliable long-term expansion was possible with all HPL, although there was some variation in platelet lysates of individual units. Therefore the use of donor recipient-matched or autologous HPL is feasible for therapeutic MSC products.     

Mesenchymal stromal cells promote or suppress the proliferation of T lymphocytes from cord blood and peripheral blood: the importance of low cell ratio and role of interleukin-6

Background aimsMesenchymal stromal cells (MSC) have been shown to possess immunomodulatory functions and proposed as a tool for managing or preventing graft-versus-host disease (GvHD) as well as promoting clinical transplantation tolerance. We investigated the capacity of human bone marrow (BM) MSC to modulate the proliferation of T cells obtained from peripheral blood (PB) and umbilical cord blood (CB). We addressed the importance of the MSC:T-cell ratio, requirement for cell contact and impact of soluble factors on the MSC-mediated effects. We also analyzed whether regulatory T cells could be modulated by MSC in co-cultures.MethodsThe effect of different MSC concentrations on T-cell proliferation induced by allogeneic, mitogenic or CD3/CD28 stimulation was analyzed using bromodeoxyuridine (BrdU) incorporation and carboxyfluorescein diacetate–succinimidyl ester (CFDA-SE) labeling. The level of regulatory T cells was assessed using quantitative real-time polymerase chain reaction (PCR) and flow cytometry analysis.ResultsMSC induced a dose- and contact-dependent inhibition of T-cell proliferation but lymphocytes from CB and PB were differentially affected. At low concentrations, MSC supported both CB and PB T-cell proliferation, rather than inhibiting their proliferation. This supportive effect was contact independent and soluble factors such interleukin-6 (IL-6) appeared to be involved. Interestingly, among the expanded T-cell population in both CB and PB, regulatory T cells were increased and were a part of the new cells promoted by MSC at low doses.ConclusionsMSC represent an attractive tool for reducing the lymphocyte response by inhibiting T-cell activation and proliferation as well as promoting tolerance by maintaining and promoting the expansion of regulatory cells. Nevertheless, the dual ability of MSC to either sustain or suppress T-cell proliferation according to conditions should be considered in the context of clinical applications.     

Dexamethasone has variable effects on mesenchymal stromal cells

Background aimsDexamethasone (Dex) is a potent synthetic member of the glucocorticoid class of steroid drugs. Frequently, Dex has been used to enhance osteogenic, chondrogenic and adipogenic differentiation of mesenchymal stromal cells (MSC). Recently, Dex was applied to promote MSC proliferation, because of the rare frequency of MSC in bone marrow, and could protect the cells from apoptosis. The effects of Dex on MSC cytobiology behavior needs to be investigated.MethodsMSC were obtained from human umbilical cord. The surface phenotype and functional characterization of MSC cultured with different concentrations of Dex were investigated, in comparison with a control group, including MSC proliferation, apoptosis, cytokine expression and immunosuppression.ResultsDifferent concentrations of Dex exerted diverse effects on MSC proliferation and apoptosis. Dex was also able to affect the pattern of cytokine expression of MSC. Furthermore, Dex impaired immunosuppression of MSC on peripheral blood mononuclear cells.ConclusionsA low dose of Dex favors MSC expansion in vitro, and protects against apoptosis. It is not suitable for MSC to be pre-treated with Dex when they are to be used to treat immunologic disease. However, when MSC are applied to promote angiogenesis, it is beneficial for them to be pre-treated with 10^?9 mol/L Dex.     

Fibrogenic Potential of Human Multipotent Mesenchymal Stromal Cells in Injured Liver

Multipotent mesenchymal stromal cells (MSC) are currently investigated clinically as cellular therapy for a variety of diseases. Differentiation of MSC toward endodermal lineages, including hepatocytes and their therapeutic effect on fibrosis has been described but remains controversial. Recent evidence attributed a fibrotic potential to MSC. As differentiation potential might be dependent of donor age, we studied MSC derived from adult and pediatric human bone marrow and their potential to differentiate into hepatocytes or myofibroblasts in vitro and in vivo. Following characterization, expanded adult and pediatric MSC were co-cultured with a human hepatoma cell line, Huh-7, in a hepatogenic differentiation medium containing Hepatocyte growth factor, Fibroblast growth factor 4 and oncostatin M. In vivo, MSC were transplanted into spleen or liver of NOD/SCID mice undergoing partial hepatectomy and retrorsine treatment. Expression of mesenchymal and hepatic markers was analyzed by RT-PCR, Western blot and immunohistochemistry. In vitro, adult and pediatric MSC expressed characteristic surface antigens of MSC. Expansion capacity of pediatric MSC was significantly higher when compared to adult MSC. In co-culture with Huh-7 cells in hepatogenic differentiation medium, albumin expression was more frequently detected in pediatric MSC (5/8 experiments) when compared to adult MSC (2/10 experiments). However, in such condition pediatric MSC expressed alpha smooth muscle more strongly than adult MSC. Stable engraftment in the liver was not achieved after intrasplenic injection of pediatric or adult MSC. After intrahepatic injection, MSC permanently remained in liver tissue, kept a mesenchymal morphology and expressed vimentin and alpha smooth muscle actin, but no hepatic markers. Further, MSC localization merges with collagen deposition in transplanted liver and no difference was observed using adult or pediatric MSC. In conclusion, when transplanted into an injured or regenerating liver, MSC differentiated into myofibroblasts with development of fibrous tissue, regardless of donor age. These results indicate that MSC in certain circumstances might be harmful due to their fibrogenic potential and this should be considered before potential use of MSC for cell therapy.     

Inactivated human platelet lysate with psoralen: a new perspective for mesenchymal stromal cell production in Good Manufacturing Practice conditions

Background aimsMesenchymal stromal cells (MSC) are ideal candidates for regenerative and immunomodulatory therapies. The use of xenogeneic protein–free Good Manufacturing Practice–compliant growth media is a prerequisite for clinical MSC isolation and expansion. Human platelet lysate (HPL) has been efficiently implemented into MSC clinical manufacturing as a substitute for fetal bovine serum (FBS). Because the use of human-derived blood materials alleviates immunologic risks but not the transmission of blood-borne viruses, the aim of our study was to test an even safer alternative than HPL to FBS: HPL subjected to pathogen inactivation by psoralen (iHPL).MethodsBone marrow samples were plated and expanded in α-minimum essential medium with 10% of three culture supplements: HPL, iHPL and FBS, at the same time. MSC morphology, growth and immunophenotype were analyzed at each passage. Karyotype, tumorigenicity and sterility were analyzed at the third passage. Statistical analyses were performed.ResultsThe MSCs cultivated in the three different culture conditions showed no significant differences in terms of fibroblast colony-forming unit number, immunophenotype or in their multipotent capacity. Conversely, the HPL/iHPL-MSCs were smaller, more numerous, had a higher proliferative potential and showed a higher Oct-3/4 and NANOG protein expression than did FBS-MSCs. Although HPL/iHPL-MSCs exhibit characteristics that may be attributable to a higher primitive stemness than FBS-MSCs, no tumorigenic mutations or karyotype modifications were observed.ConclusionsWe demonstrated that iHPL is safer than HPL and represents a good, Good Manufacturing Practice–compliant alternative to FBS for MSC clinical production that is even more advantageous in terms of cellular growth and stemness.     

Modified Extracorporeal Photopheresis with Cells from a Healthy Donor for Acute Graft-versus-Host Disease in a Mouse Model

Background

Graft-versus-host disease (GvHD) is a major challenge after hematopoietic stem cell transplantation but treatment options for patients are still limited. In many cases first-line treatment with glucocorticoids is not successful. Among second-line therapies the extracorporeal photopheresis (ECP) is frequently performed, due to induction of selective tolerance instead of general immunosuppression. However, for some patients with severe acute GvHD the leukapheresis step of the ECP procedure is physically exhausting and limits the number of ECP cycles.

Methods

We hypothesized that leukocytes from healthy cell donors could be used as a replacement for ECP leukocytes gained from the GvHD patient. For this purpose we used a well established mouse model of acute GvHD. The ECP therapy was based on cells with the genetic background of the initial donor of the stem cell transplantation. As a precondition we developed a protocol representing conventional ECP in mice equivalent to clinical used ECP setup.

Results

We could demonstrate that conventional, clinically derived ECP setup is able to alleviate acute GvHD. By using leukocytes obtained from healthy mice with the bone marrow donor’s genetic background we could not observe a statistically significant therapeutic effect.

Conclusions

Conventional human ECP setup is effective in the mouse model of severe acute GvHD. In addition we could not prove that ECP cells from healthy mice with bone marrow donor’s genetic background are as effective as ECP cells derived from GvHD mice. Based on our findings, new questions arise for further studies, in which the cellular characteristics for ECP mediated immune tolerance are a matter of investigation.     

Impaired differentiation potential of human trabecular bone mesenchymal stromal cells from elderly patients

Background aimsAdvances in bone tissue engineering with mesenchymal stromal cells (MSC) as an alternative to conventional orthopedic procedures has opened new horizons for the treatment of large bone defects. Bone marrow (BM) and trabecular bone are both sources of MSC. Regarding clinical use, we tested the potency of MSC from different sources.MethodsWe obtained MSC from 17 donors (mean age 64.6 years) by extensive washing of trabecular bone from the femoral head and trochanter, as well as BM aspirates of the iliac crest and trochanter. The starting material was evaluated by histologic analysis and assessment of colony-forming unit–fibroblasts (CFU-F). The MSC populations were compared for proliferation and differentiation potential, at RNA and morphologic levels.ResultsMSC proliferation potential and immunophenotype (expression of CD49a, CD73, CD90, CD105, CD146 and Stro-1) were similar whatever the starting material. However, the differentiation potential of MSC obtained by bone washing was impaired compared with aspiration; culture-amplified cells showed few Oil Red O-positive adipocytes and few mineralized areas and formed inconsistent Alcian blue-positive high-density micropellets after growth under adipogenic, osteogenic and chondrogenic conditions, respectively. MSC cultured with 1 ng/mL fibroblast growth factor 2 (FGF-2) showed better differentiation potential.ConclusionsTrabecular bone MSC from elderly patients is not good starting material for use in cell therapy for bone repair and regeneration, unless cultured in the presence of FGF-2.     

Microbial community structure and dynamics in a mixotrophic nitrogen removal process using recycled spent caustic under different loading conditions

A laboratory-scale Bardenpho process was established to investigate the proper nitrogen loading rate (NLR) when modified spent caustic (MSC) is applied as electron donor and alkalinity source for denitrification. MSC injection induced autotrophic nitrogen removal with sulfur as electron donor and heterotrophic denitrification. The nitrogen removal rate (NRR) did not increase proportionally to NLR. Based on the total nitrogen concentration in the effluent observed in the trials with MSC, the NLR in the influent should not exceed 0.15 kg N/m³ d in order to satisfy water quality regulations. Microbial communities in the anoxic reactors were characterized by pyrosequencing of 16S rRNA gene sequences amplified by the polymerase chain reaction of DNA extracted from sludge samples. Microbial diversity was lower as MSC dosage was increased, and the injection of MSC caused an increase in SOB belonging to the genus Thiobacillus which is responsible for denitrification using sulfur.