Doses Of Mesenchymal Stromal Cells Research Articles

Inter- and Intra-donor Variability in Bone Marrow-Derived Mesenchymal Stromal Cells: Implications for Clinical Applications

Mesenchymal stromal cells (MSCs) are attractive as a therapeutic modality in multiple disease conditions characterized by inflammation and vascular compromise. Logistically they are advantageous since they can be isolated them from adult tissue sources, such as bone marrow (BM). The phase 2a START clinical trial determined BM-MSCs to be safe in patients with moderate to severe acute respiratory distress syndrome (ARDS). Herein, we examine a subset of the clinical doses of MSCs generated for the phase 2a START trial from three unique donors (1-3), where one of the donors’ donated BM on two separate occasions (Donor 3 and 3W). The main objective of this study was to correlate properties of the cells from the four lots with plasma biomarkers from treated patients and relevant to ARDS outcomes. To do this we evaluated MSC donor lots for (1) post-thaw viability, (2) growth kinetics, (3) metabolism, (4) surface marker expression, (5) protein expression, (6) immunomodulatory ability, and (7) their functional effects on regulating endothelial cell permeability. MSC-specific marker expression and protection of thrombin-challenged endothelial barrier permeability was similar among all four donor lots. Inter and intra-donor variability was observed in all the other in vitro assays. Furthermore, patient plasma ANG-2 and Protein C levels at 6 hours post-transfusion were correlated to cell viability in an inter- and intra-donor dependent manner. These findings highlight the potential of donor dependent (inter-) and collection dependent (intra-) effects in patient biomarker expression.

A Phase I Dose-Escalation Clinical Trial to Assess the Safety and Efficacy of Umbilical Cord-Derived Mesenchymal Stromal Cells in Knee Osteoarthritis.

Osteoarthritis (OA) is the most common degenerative joint disease. Mesenchymal stromal cells (MSC) are promising cell-based therapy for OA. However, there is still a need for additional randomized, dose-dependent studies to determine the optimal dose and tissue source of MSC for improved clinical outcomes. Here, we performed a dose-dependant evaluation of umbilical cord (UC)-derived MSC (Celllistem) in a murine model and in knee OA patients. For the preclinical study, a classical dose (200.000 cells) and a lower dose (50.000 cells) of Cellistem were intra-articularly injected into the mice knee joints. The results showed a dose efficacy response effect of Cellistem associated with a decreased inflammatory and degenerative response according to the Pritzker OARSI score. Following the same approach, the dose-escalation phase I clinical trial design included 3 sequential cohorts: low-dose group (2 × 106 cells), medium-dose group (20 × 106), and high-dose group (80 × 106). All the doses were safe, and no serious adverse events were reported. Nonetheless, 100% of the patients injected with the high-dose experienced injection-related swelling in the knee joint. According to WOMAC total outcomes, patients treated with all doses reported significant improvements in pain and function compared with baseline after 3 and 6 months. However, the improvements were higher in patients treated with both medium and low dose as compared to high dose. Therefore, our data demonstrate that the intra-articular injection of different doses of Cellistem is both safe and efficient, making it an interesting therapeutic alternative to treat mild and symptomatic knee OA patients. Trial registration ClinicalTrials.gov NCT03810521.

Human Wharton’s jelly-derived mesenchymal stromal cells promote bone formation in immunodeficient mice when administered into a bone microenvironment

BackgroundWharton’s Jelly (WJ) Mesenchymal Stromal Cells (MSC) have emerged as an attractive allogeneic therapy for a number of indications, except for bone-related conditions requiring new tissue formation. This may be explained by the apparent recalcitrance of MSC,WJ to differentiate into the osteogenic lineage in vitro, as opposed to permissive bone marrow (BM)-derived MSCs (MSC,BM) that readily commit to bone cells. Consequently, the actual osteogenic in vivo capacity of MSC,WJ is under discussion.MethodsWe investigated how physiological bone environments affect the osteogenic commitment of recalcitrant MSCs in vitro and in vivo. To this end, MSC of BM and WJ origin were co-cultured and induced for synchronous osteogenic differentiation in vitro using transwells. For in vivo experiments, immunodeficient mice were injected intratibially with a single dose of human MSC and bone formation was evaluated after six weeks.ResultsCo-culture of MSC,BM and MSC,WJ resulted in efficient osteogenesis in both cell types after three weeks. However, MSC,WJ failed to commit to bone cells in the absence of MSC,BM’s osteogenic stimuli. In vivo studies showed successful bone formation within the medullar cavity of tibias in 62.5% of mice treated with MSC, WJ. By contrast, new formed trabeculae were only observed in 25% of MSC,BM-treated mice. Immunohistochemical staining of human COXIV revealed the persistence of the infused cells at the site of injection. Additionally, cells of human origin were also identified in the brain, heart, spleen, kidney and gonads in some animals treated with engineered MSC,WJ (eMSC,WJ). Importantly, no macroscopic histopathological alterations, ectopic bone formation or any other adverse events were detected in MSC-treated mice.ConclusionsOur findings demonstrate that in physiological bone microenvironment, osteogenic commitment of MSC,WJ is comparable to that of MSC,BM, and support the use of off-the-shelf allogeneic MSC,WJ products in bone repair and bone regeneration applications.

Allogenic mesenchymal stromal cells and their extracellular vesicles in COVID-19 induced ARDS: a randomized controlled trial

Background and aimsThe main causes of death in patients with severe Coronavirus disease-2019 (COVID-19) are acute respiratory distress syndrome (ARDS) and multiorgan failure caused by a severe inflammatory cascade. Novel treatment strategies, such as stem-cell-based therapy and their derivatives can be used to relieve inflammation in these cases. In this study, we aimed to evaluate the safety and efficacy of therapy using mesenchymal stromal cells (MSCs) and their derived extracellular vesicles in COVID-19 patients.Materials and methodsCOVID-19 patients with ARDS were included in this study and allocated into two study and control groups using block randomization. While all patients received recommended treatment based on guidelines from the national advisory committee for COVID-19 pandemic, the two intervention groups received two consecutive injections of MSCs (100 × 106 cells) or one dose of MSCs (100 × 106 cells) followed by one dose of MSC-derived extracellular vesicles (EVs). Patients were assessed for safety and efficacy by evaluating clinical symptoms, laboratory parameters, and inflammatory markers at baseline and 48 h after the second intervention.ResultsA total number of 43 patients (the MSC alone group = 11, MSC plus EV group = 8, and control group = 24) were included in the final analysis. Mortality was reported in three patients in the MSC alone group (RR: 0.49; 95% CI 0.14–1.11; P = 0.08); zero patient in the MSC plus EV group (RR: 0.08; 95% CI 0.005–1.26; P = 0.07) and eight patients in the control group. MSC infusion was associated with a decrease in inflammatory cytokines such as IL-6 (P = 0.015), TNF-α (P = 0.034), IFN-γ (P = 0.024), and CRP (P = 0.041).ConclusionMSCs and their extracellular vesicles can significantly reduce the serum levels of inflammatory markers in COVID-19 patients, with no serious adverse events.Trial registration IRCT, IRCT registration number: IRCT20200217046526N2. Registered 13th April 2020, http://www.irct.ir/trial/47073.

Safety and efficacy of mesenchymal stem cells in severe/critical patients with COVID-19: A systematic review and meta-analysis.

SummaryBackgroundThe present study aims to better understand the efficacy and safety of mesenchymal stromal cells (MSCs) in treating severe/critical patients with COVID-19.MethodsPubMed, the Cochrane Library, and the Chinese electronic database CNKI were searched from inception up to Dec 19, 2021. Original comparative studies for MSC treatment + standard treatment for severe/critical patients with COVID-19, with placebo or standard treatment as the control group, were included. The primary outcomes were in-hospital mortality and adverse events (AEs). A meta-analysis was performed to compare the mortality rates between the two groups. Then, a subgroup analysis was performed according to the category of the disease (severe or critical) and MSC dose. Afterwards, a descriptive analysis was performed for AEs and secondary outcomes. The funnel plot and Egger's test were used for the publication bias assessment.FindingsCompared to placebo or standard care, MSCs provide significant benefit in the treatment of patients with severe/critical COVID-19, in terms of in-hospital mortality rate (odds ratio: 0.52, 95% CI 0.32-0.84), with very low heterogeneity (P=0.998 [Q test], I2=0.0%) and less AEs. No significant difference was found in mortality rate due to the different disease categories or MSC doses. Furthermore, no publication bias was found.InterpretationThe present study demonstrates that MSCs are highly likely to reduce mortality and are safe to use for patients with severe or critical COVID-19, regardless of whether 1-3 doses are applied. However, due to the small sample size of the included studies, further high-quality, large-scale trials are needed to confirm this statement in the future.FundingThe National Key Research and Development Program of China (No. 2020YFC0860900), the Science and Technology Project of Wuhan (No. 2020020602012112), the Tianjin Science and Technology Research Program (18PTSYJC00070 and 16PTWYHZ00030), Haihe Laboratory of Cell Ecosystem Innovation Fund (HH22KYZX0046), and the Tianjin Free Trade Zone Innovation Development Project (ZMCY-03-2021002-01) funded the study. We are also grateful for the support from the 3551 Talent Plan of China Optics Valley.

Intravenously transplanted mesenchymal stromal cells: a new endocrine reservoir for cardioprotection

BackgroundIntravenous administration of mesenchymal stromal cells (MSCs) has an acknowledged competence of cardiac repair, despite a lack of systematic description of the underlying biological mechanisms. The lung, but not the heart, is the main trapped site for intravenously transplanted MSCs, which leaves a spatial gap between intravenously transplanted MSCs and the injured myocardium. How lung-trapped MSCs after intravenous transplantation rejuvenate the injured myocardium remains unknown.MethodsMSCs were isolated from human placenta tissue, and DF-MSCs or Gluc-MSCs were generated by transduced with firefly luciferase (Fluc)/enhanced green fluorescence protein (eGFP) or Gaussia luciferase (Gluc) lactadherin fusion protein. The therapeutic efficiency of intravenously transplanted MSCs was investigated in a murine model of doxorubicin (Dox)-induced cardiotoxicity. Trans-organ communication from the lung to the heart with the delivery of blood was investigated by testing the release of MSC-derived extracellular vesicles (MSC-EVs), and the potential miRNA inner MSC-EVs were screened out and verified. The potential therapeutic miRNA inner MSC-EVs were then upregulated or downregulated to assess the further therapeutic efficiencyResultsDox-induced cardiotoxicity, characterized by cardiac atrophy, left ventricular dysfunction, and injured myocardium, was alleviated by consecutive doses of MSCs. These cardioprotective effects might be attributed to suppressing GRP78 triggering endoplasmic reticulum (ER) stress-induced apoptosis in cardiomyocytes. Our results confirmed that miR-181a-5p from MSCs-derived EVs (MSC-EVs) inhibited GRP78. Intravenous DF-MSCs were trapped in lung vasculature, secreted a certain number of EVs into serum, which could be confirmed by the detection of eGFP+ EVs. GLuc activity was increased in serum EVs from mice administrated with GLuc-MSCs. MiR-181a-5p, inhibiting GRP78 with high efficacy, was highly expressed in serum EVs and myocardium after injecting consecutive doses of MSCs into mice treated with Dox. Finally, upregulation or downregulation of miR-181a-5p levels in MSC-EVs enhanced or weakened therapeutic effects on Dox-induced cardiotoxicity through modulating ER stress-induced apoptosis.ConclusionsThis study identifies intravenously transplanted MSCs, as an endocrine reservoir, to secrete cardioprotective EVs into blood continuously and gradually to confer the trans-organ communication that relieves Dox-induced cardiotoxicity.

Intravenous administration of mesenchymal stromal cells leads to a dose-dependent coagulopathy and is unable to attenuate acute traumatic coagulopathy in rats.

Mesenchymal stromal cells (MSCs) express surface tissue factor (TF), which may affect hemostasis and detract from therapeutic outcomes of MSCs if administered intravenously. In this study, we determine a safe dose of MSCs for intravenous (IV) administration and further demonstrate the impact of IV-MSC on acute traumatic coagulopathy (ATC) in rats. Tissue factor expression of rat bone marrow-derived mesenchymal stromal cell (BMSC) or adipose-derived mesenchymal stromal cell (AMSC) was detected by immunohistochemistry and enzyme-linked immunosorbent assay. The coagulation properties were measured in MSC-treated rat whole blood, and blood samples were collected from rats after IV administration of MSCs. Acute traumatic coagulopathy rats underwent polytrauma and 40% hemorrhage, followed by IV administration of 5 or 10 million/kg BMSCs (BMSC-5, BMSC-10), or vehicle at 1 hour after trauma. Rat MSCs expressed TF, and incubation of rat BMSCs or AMSCs with whole blood in vitro led to a significantly shortened clotting time. However, a dose-dependent prolongation of prothrombin time with reduction in platelet counts and fibrinogen was found in healthy rat treated with IV-MSCs. Bone marrow-derived mesenchymal stromal cells at 5 million/kg or less led to minimal effect on hemostasis. Mesenchymal stromal cells were not found in circulation but in the lungs after IV administration regardless of the dosage. Acute traumatic coagulopathy with prolonged prothrombin time was not significantly affected by 5 or 10 million/kg BMSCs. Intravenous administration of 10 million/kg BMSCs led to significantly lower fibrinogen and platelet counts, while significantly higher levels of lactate, wet/dry weight ratio, and leukocyte infiltration in the lung were present compared with BMSC-5 or vehicle. No differences were seen in immune or inflammatory profiles with BMSC treatment in ATC rats, at least in the acute timeframe. Intravenous administration of MSCs leads to a risk of coagulopathy associated with a dose-dependent reduction in platelet counts and fibrinogen and is incapable of restoring hemostasis of rats with ATC after polytrauma and hemorrhagic shock.

Mesenchymal Stromal Cells for the Treatment of Graft Versus Host Disease.

Graft versus host disease (GvHD) is a life-threating complication of allogeneic hematopoietic stem cell transplantation, which is initially treated with high dose corticosteroids. Approximately 50% of acute GvHD cases are resistant to steroid treatment, and two-year mortality rates in those steroid-resistant patients exceed 80%. Chronic GvHD necessitates prolonged corticosteroid use, which is typically associated with limited efficacy and troublesome adverse effects. No agent has yet been established as an optimal second line therapy for either acute or chronic GvHD, but mesenchymal stromal cells (MSCs) have shown substantial promise. MSCs promote an immunosuppressive and immunoregulatory environment via multifactorial mechanisms, including: secretion of proteins/peptides/hormones; transfer of mitochondria; and transfer of exosomes or microvesicles containing RNA and other molecules. A large number of clinical studies have investigated MSCs from various sources as a treatment for acute and/or chronic GvHD. MSCs are generally safe and well tolerated, and most clinical studies have generated encouraging efficacy results, but response rates have varied. Confounding factors include variability in MSC donor types, production methodology and dose regimens, as well as variations in study design. It is well-established that extensive culture expansion of primary donor-derived MSCs leads to marked changes in functionality, and that there is a high level of inter-donor variability in MSC properties. However, recent manufacturing innovations may be capable of overcoming these problems. Further adequately powered prospective studies are required to confirm efficacy and establish the place of MSC therapy in the treatment of this condition.

MESENCHYMAL STROMAL CELLS PROTECT AGAINST VASCULAR DAMAGE AND DEPRESSION-LIKE BEHAVIOR IN MICE SURVIVING CEREBRAL MALARIA

<h3>Introduction</h3> Cerebral malaria (CM) is a severe systemic inflammatory disease, that leads to behavioral impairments, such as depression. Currently, there are no therapies to treat the neurological sequelae of CM, and mesenchymal stromal cells (MSC) may be an alternative. <h3>Objectives</h3> To investigate the effects of MSC therapy on the blood-brain barrier (BBB), leukocyte rolling and adherence in the brain, and depression like-behavior in experimental CM. <h3>Methods</h3> Male C57BL/6 mice were infected with Plasmodium berghei ANKA (PbA, 1 × 106, intraperitoneally). At day 6, PbA-infected animals received chloroquine (25 mg/kg orally for seven days) and were then randomized to receive MSC (105 cells) or saline intravenously. All animal experiments were approved by the ethics committee of the Oswaldo Cruz Institute (L-012/2015), and had a number of 3 to 12 animals per group. In vitro, endothelial cells were used to evaluate the effects of conditioned media derived from MSC (CMMSC) on cell viability by lactate dehydrogenase (LDH) release. We used a one-way analysis of variance with post-hoc Tukey test to assess the differences between more than two groups and Student‘s t test when data from only two groups were analyzed. <h3>Results</h3> MSC therapy improved the vascular damage at 7 days after infection (dpi). Evans blue assay and intravital microscopy showed that infected mice, who received only saline, had an increase in BBB permeability (n=7; 0.0084±0.0016) and adherent leukocytes (n=3; 3.76±0.23). PbA+MSC mice had reduced BBB permeability (n=4; 0.0063±0.0012) and leukocyte adhesion in the brain microvasculature (n=4; 2.18±0.37). PbA-infected mice presented reduced levels of BDNF 7 dpi (n=4; 0.025±0.0015), and depression-like behavior 15 dpi evaluated by the tail suspension test (TST, n=5; 44.38±4) and the forced swim test (FST, n=5; 45.5±4.8). MSC therapy restored BDNF levels (n=11; 0.029±0.0008) and mitigated behavioral alterations (n=5; TST:18±2.7; FST:18.2±2.8). CMMSC reduced LDH release in endothelial cells stimulated with heme (group heme: 1,89±0,11; group CMMSC: 0,96±0,06), suggesting a paracrine mechanism of action. <h3>Conclusion</h3> A single dose of MSC as an adjuvant therapy protected against vascular damage and improved depression-like behavior in mice that survived experimental CM.

Dose- and Time-Dependent Effects of Human Mesenchymal Stromal Cell Infusion on Cardiac Allograft Rejection in Mice.

Heart transplantation is the final life-saving therapeutic strategy for many end-stage heart diseases. Long-term immunosuppressive regimens are needed to prevent allograft rejection. Mesenchymal stromal cells (MSCs) have been shown as immunomodulatory therapy for organ transplantation. However, the effect of dose and timing of MSC treatment on heart transplantation has not yet been examined. In this study, we infused three doses (1 × 106, 2 × 106, or 5 × 106 cells) of human MSCs (hMSCs) to the recipient BALB/c mice before (7 days or 24 h) or after (24 h) receiving C57BL/6 cardiac transplants. We found that infusion of high dose hMSCs (5 × 106) at 24 h post-transplantation significantly prolonged the survival time of cardiac grafts. To delineate the underlying mechanism, grafts, spleens, and draining lymph nodes were harvested for analysis. Dose-dependent effect of hMSC treatment was shown in: (1) alleviation of International Society of Heart and Lung Transplantation (ISHLT) score in grafts; (2) reduction of the population of CD4+ and CD8+ T cells; (3) increase of regulatory T (Treg) cells; (4) and decrease of serum levels of inflammatory cytokines and donor-specific antibodies. Taken together, we showed timing critical and dose-dependent immunomodulatory effects of hMSC treatment against acute allograft rejection in a mouse model of heart transplantation.

Cross-matching of allogeneic mesenchymal stromal cells eliminates recipient immune targeting.

Allogeneic mesenchymal stromal cells (MSCs) have been used clinically for decades, without cross‐matching, on the assumption that they are immune‐privileged. In the equine model, we demonstrate innate and adaptive immune responses after repeated intra‐articular injection with major histocompatibility complex (MHC) mismatched allogeneic MSCs, but not MHC matched allogeneic or autologous MSCs. We document increased peri‐articular edema and synovial effusion, increased synovial cytokine and chemokine concentrations, and development of donor‐specific antibodies in mismatched recipients compared with recipients receiving matched allogeneic or autologous MSCs. Importantly, in matched allogeneic and autologous recipients, but not mismatched allogeneic recipients, there was increased stromal derived factor‐1 along with increased MSC concentrations in synovial fluid. Until immune recognition of MSCs can be avoided, repeated clinical use of MSCs should be limited to autologous or cross‐matched allogeneic MSCs. When non–cross‐matched allogeneic MSCs are used in single MSC dose applications, presensitization against donor MHC should be assessed.

Bone marrow stromal cell therapy improves survival after radiation injury but does not restore endogenous hematopoiesis

The only available option to treat radiation-induced hematopoietic syndrome is allogeneic hematopoietic cell transplantation, a therapy unavailable to many patients undergoing treatment for malignancy, which would also be infeasible in a radiological disaster. Stromal cells serve as critical components of the hematopoietic stem cell niche and are thought to protect hematopoietic cells under stress. Prior studies that have transplanted mesenchymal stromal cells (MSCs) without co-administration of a hematopoietic graft have shown underwhelming rescue of endogenous hematopoiesis and have delivered the cells within 24 h of radiation exposure. Herein, we examine the efficacy of a human bone marrow-derived MSC therapy delivered at 3 h or 30 h in ameliorating radiation-induced hematopoietic syndrome and show that pancytopenia persists despite MSC therapy. Animals exposed to radiation had poorer survival and experienced loss of leukocytes, platelets, and red blood cells. Importantly, mice that received a therapeutic dose of MSCs were significantly less likely to die but experienced equivalent collapse of the hematopoietic system. The cause of the improved survival was unclear, as complete blood counts, splenic and marrow cellularity, numbers and function of hematopoietic stem and progenitor cells, and frequency of niche cells were not significantly improved by MSC therapy. Moreover, human MSCs were not detected in the bone marrow. MSC therapy reduced crypt dropout in the small intestine and promoted elevated expression of growth factors with established roles in gut development and regeneration, including PDGF-A, IGFBP-3, IGFBP-2, and IGF-1. We conclude that MSC therapy improves survival not through overt hematopoietic rescue but by positive impact on other radiosensitive tissues, such as the intestinal mucosa. Collectively, these data reveal that MSCs could be an effective countermeasure in cancer patients and victims of nuclear accidents but that MSCs alone do not significantly accelerate or contribute to recovery of the blood system.

Mesenchymal Stromal Cell (MSC) Compassionate Use in France in Treatment of Steroid-Refractory Graft-Versus-Host-Disease (GVHD) after Approval By the Expert Committee of Société Française De Greffe De Moelle Et Thérapie Cellulaire (SFGM-TC)

Mesenchymal Stromal Cell (MSC) Compassionate Use in France in Treatment of Steroid-Refractory Graft-Versus-Host-Disease (GVHD) after Approval By the Expert Committee of Société Française De Greffe De Moelle Et Thérapie Cellulaire (SFGM-TC)

Mesenchymal Stromal Cells (MSCs) Experience in France to Prevent Graft Failure after Hematopoietic Stem Cell Transplantation: A Retrospective Study from the MSCs/CTL Group of the Francophone Society SFGM-TC

Graft failure occurs in 3-5% of hematopoietic stem cell transplantations (HSCT) and raises up to 10% for mismatched HSCT. It is a severe complication leading to lethal infections or bleedings. Several studies reported that engraftment could be improved by mesenchymal stromal cells (MSCs) infusion. Those cells are multipotent cells capable of differentiation in at least 3 lineages (adipocytes, chondrocytes and osteocytes) and of supportive effects on hematopoiesis. This treatment is considered as an Advanced Therapy Medicinal Product in France and there is currently no authorization for its use outside of clinical trials. We retrospectively analyzed the demands from HSCT French centers to the expert committee of the SFGMTC and the French regulatory agency (ANSM), since 2014, in order to ask for MSCs exceptional recourse for patients with graft failure. Nine requests for MSCs were made. One patient did not receive any MSCs because MSCs bag was contaminated, another one had an haploidentical transplantation without MSCs instead. Finally, 7 patients received 1 or 2 infusions of MSCs (Table). Median age was of 6 years (4-23), sex ratio was of 2,5. Two patients (29%) had an acute lymphoblastic leukemia (ALL) and 5 patients (71%) had an aplastic anemia (idiopathic n=4, congenital n=1). Five patients had received one transplantation, and 2 patients had received two transplantations, followed by a primary graft failure (n=6) and a secondary graft failure (n=1). Only 2 patients had received a myeloablative conditioning regimen (MAC) for the first procedure, one chemo- and one TBI- based. The other 5 patients had received a reduced-intensity conditioning (RIC) regimen, 4 of them with 2 grays TBI. Two patients had received a cord blood unit and 5 bone marrows from 1 sibling, 3 haploidentical and 1 mismatched donors. Only 2 patients had received antithymoglobulins in their previous regimen. Engraftments failed despite a median richness of 5,14.106 CD34 cells/kg/bone marrow graft (1,84-9,5) and of 1,25.105CD34 cells/kg/cord blood unit (1,2-1,3). Median delay between first HSCT with graft failure and MSCs infusion was of 2 months (1-32). To prepare last HSCT,six patients received a reduced intensity conditioning regimen with 2 grays TBI (Baltimore), and one patient received a myeloablative, chemo-based, regimen, with antithymoglobulins. Three patients received a graft from the same previous donor. Six patients received a haploidentical graft (5 bone marrows, 1 peripheral blood stem cells), and 1 received bone marrow from a mismatched donor. Median number of CD34+ cells was of 9,02.106/kg (1,61-12,43). All MSCs were from 8 pooled donors (OBNITIX®) except for one patient who received MSCs from a relative donor (which was different from the HSCT donor). All infusions were well tolerated and made on the same day as HSCT, apart from one patient who received MSCs for a secondary graft failure on day 228 post-transplantation, followed by an infusion of CD34+ cells on day 231, and a second infusion of MSCs on day 259. Mean dose of MSCs was of 1,72.106/kg (1,25-3,1). Median time for neutrophil recovery (neutrophils over 0.5 G/L) and platelet recovery (platelets over 50 G/L) on 3 consecutive days was respectively of 23 days (10-34) and 35 days (26-238). At day 30, 5 patients (71%) had a full donor chimerism. Only one patient presented a graft failure leading to a third HSCT. No secondary graft failure occurred after a median follow-up of 13 months (4-104). At last follow-up, none of the patients who achieved platelet and neutrophil recovery required neither blood or platelets transfusion nor thrombopoietin receptor analogs. Infusion of MSCs at the time of HSCT to prevent graft failure was safe and effective for 6/7 patients. Larger prospective trials are necessary to confirm MSCs impact on engraftment and graft function. Table Disclosures Dalle: AbbVie Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria; Jazz Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Orchard: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Medac: Consultancy, Honoraria; Bellicum: Consultancy, Honoraria; Sanofi-Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees. Rubio:Medac: Consultancy; Gilead: Honoraria; MSD: Honoraria; Novartis: Honoraria; Neovii: Research Funding.

Mesenchymal stromal cells protect against vascular damage and depression-like behavior in mice surviving cerebral malaria

BackgroundMalaria is one of the most critical global infectious diseases. Severe systemic inflammatory diseases, such as cerebral malaria, lead to the development of cognitive and behavioral alterations, such as learning disabilities and loss of memory capacity, as well as increased anxiety and depression. The consequences are profound and usually contribute to reduce the patient’s quality of life. There are no therapies to treat the neurological sequelae of cerebral malaria. Mesenchymal stromal cells (MSCs) may be an alternative, since they have been used as therapy for neurodegenerative diseases and traumatic lesions of the central nervous system. So far, no study has investigated the effects of MSC therapy on the blood-brain barrier, leukocyte rolling and adherence in the brain, and depression like-behavior in experimental cerebral malaria.MethodsMale C57BL/6 mice were infected with Plasmodium berghei ANKA (PbA, 1 × 106 PbA-parasitized red blood cells, intraperitoneally). At day 6, PbA-infected animals received chloroquine (25 mg/kg orally for seven consecutive days) as the antimalarial treatment and were then randomized to receive MSCs (1 × 105 cells in 0.05 ml of saline/mouse) or saline (0.05 ml) intravenously. Parasitemia, clinical score, and survival rate were analyzed throughout the experiments. Evans blue assay was performed at 6, 7, and 15 days post-infection (dpi). Behavioral tests were performed at 5 and 15 dpi. Intravital microscopy experiments and brain-derived neurotrophic factor (BDNF) protein expression analyses were performed at 7 dpi, whereas inflammatory mediators were measured at 15 dpi. In vitro, endothelial cells were used to evaluate the effects of conditioned media derived from MSCs (CMMSC) on cell viability by lactate dehydrogenase (LDH) release.ResultsPbA-infected mice presented increased parasitemia, adherent leukocytes, blood-brain barrier permeability, and reduced BDNF protein levels, as well as depression-like behavior. MSCs mitigated behavioral alterations, restored BDNF and transforming growth factor (TGF)-β protein levels, and reduced blood-brain barrier dysfunction and leukocyte adhesion in the brain microvasculature. In a cultured endothelial cell line stimulated with heme, CMMSC reduced LDH release, suggesting a paracrine mechanism of action.ConclusionA single dose of MSCs as adjuvant therapy protected against vascular damage and improved depression-like behavior in mice that survived experimental cerebral malaria.

Mesenchymal stromal cells for the prophylaxis and treatment of graft-versus-host disease\u2014a meta-analysis

BackgroundGraft-versus-host disease (GvHD) is the main life-threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT). Thirty to 80% of GvHD patients do not respond to first-line treatment and a second-line treatment is not universally established. Based on their immunomodulatory properties, mesenchymal stromal cells (MSC) have been proposed for the prevention and the treatment of GvHD in patients undergoing HSCT. Unfortunately, previous studies reported conflicting results regarding the prophylactic and therapeutic effects of MSC for GvHD. Consequently, we carried out a meta-analysis to clarify whether MSC administration can improve the dismal outcome of these patients.MethodsWe carried out a systematic review and selected studies (2004–2019) reporting data about the administration of allogeneic MSC for the prevention (n = 654 patients) or treatment of acute (n = 943 patients) or chronic (n = 76 patients) GvHD after HSCT. Our primary outcome was overall survival at the last follow-up. The secondary outcomes were the response and development of GvHD. Subgroup analyses included age, MSC dose, first infusion day after HSCT, number of organs and organ-specific involvement, acute GvHD grade (I–IV), and chronic GvHD grade (limited or extensive).ResultsPatients infused with MSC for GvHD prophylaxis showed a 17% increased overall survival (95% CI, 1.02–1.33) and a reduced incidence of acute GvHD grade IV (RR = 0.22; 95% CI, 0.06–0.81) and chronic GvHD (RR = 0.64; 95% CI, 0.47–0.88) compared with controls. Overall survival of acute GvHD patients (0.50; 95% CI, 0.41–0.59) was positively correlated with MSC dose (P = 0.0214). The overall response was achieved in 67% (95% CI, 0.61–0.74) and was complete in 39% (95% CI, 0.31–0.48) of acute patients. Organ-specific response was higher for the skin. Twenty-two percent (95% CI, 0.16–0.29) of acute patients infused with MSC developed chronic GvHD. Sixty-four percent (95% CI, 0.47–0.80) of chronic patients infused with MSC survived; the overall response was 66% (95% CI, 0.55–0.76) and was complete in 23% (95% CI 0.12–0.34) of patients.ConclusionsOur meta-analysis indicates that allogeneic MSC could be instrumental for the prophylaxis and treatment of GvHD. Future trials should investigate the effect of the administration of MSC as an adjuvant therapy for the treatment of patients with GvHD from the onset of the disease.

What Happens When You Administer Mesenchymal Stromal Cells During Normalthermic Machine Perfusion of Porcine Kidneys: Possible and Helpful, or not?

K Rozenberg 1, L Knijff 1, J M Sierra Parraga 2, L Lo Faro 1, M J Hoogduijn 2, C 2, J Hunter 1, R Ploeg 1&#x0D; &#x0D; Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom&#x0D; Department of Internal Medicine, Nephrology and Transplantation, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands&#x0D; &#x0D; BackgroundDonation after circulatory death kidneys are widely used to increase the donor pool, despite their inferior quality. Normothermic machine perfusion (NMP) could provide a platform to assess organ viability prior to transplantation and offers the unique opportunity for active interventions to an isolated organ. Mesenchymal stromal cells (MSC) have been shown to possess potent anti-inflammatory and regenerative properties ameliorating ischaemia reperfusion injury. However, the most common delivery route of MSC is intravenous infusion, which is associated with off-target distribution. We aimed to determine the dose of MSC needed to allow successful homing in donor kidneys during NMP without adversely affecting renal perfusion dynamics.&#x0D; MethodsPorcine slaughterhouse kidneys with 20 min warm ischaemia were retrieved and underwent 3h hypothermic machine perfusion followed by NMP for 7h. An oxygenated, autologous blood-based solution containing albumin, electrolytes and nutrients was used as perfusate. Following 1h of NMP, either a vehicle, 2 x 106, 10 x 106 or 50 x 106 labelled (Qdots) porcine adipose derived MSC (n=3 per group) were injected into the cannulated renal artery. Physiological recordings were taken regularly. Perfusate, urine and biopsies were obtained for biomarker analysis and to locate MSC.&#x0D; ResultsNo difference was found in average renal blood flow (p=0.668), renal resistance (p=0.828) and urine production (p=0.307) between all MSC groups compared to control. Damage markers LDH and AST increased during NMP and remained similar between groups (p=0.816 and p=0.312). Confocal microscopy demonstrated mainly glomerular localization of MSC (Figure 1), but they were also observed in the capillary network around the tubules. Additionally, a significant percentage of localised MSC was observed in the glomeruli in the 10 and 50 million MSC groups compared to 2 million MSC (p=0.002 and p&lt;0.0001). No differences were observed between the 2 and 10 million MSCs group (p&gt;0.05). There is a significant increase in secreted inflammatory mediator PGE2 with time in all groups (P&lt;0.05).&#x0D; DiscussionAdministration of different doses of MSC to the donor kidneys during NMP is safe and feasible. MSC successfully homed in the glomeruli. This model provides us with the opportunity of getting a better insight in the interaction between MSC and injured donor kidney: how do MSC or their released secretome affect tissue integrity and renal function.

The Importance of Dosing, Timing, and (in)Activation of Adipose Tissue-Derived Mesenchymal Stromal Cells on Their Immunomodulatory Effects.

Mesenchymal stromal cells (MSCs) are attractive candidates for immunomodulatory cell therapy. However, it remains unknown how far therapeutic efficacy and potency are dependent on the dosage and activity of the MSCs. We previously observed that infusion of MSCs leads to rapid and transient changes in cytokine expression in blood, lung, and liver. In the present study, increasing doses of syngeneic adipose tissue-derived MSCs were infused in healthy mice and systemic changes in G-CSF, IL6, IL-10, and CXCL5 were detected 2 h after administration of 3 × 105 MSCs per animal, but not at lower doses. In lung and liver tissue, dose-dependent effects of MSCs on cytokine mRNA expression levels were detected from doses as low as 3 × 103 MSCs. Infusion of secretome-deficient or IFNγ-activated MSCs in healthy mice had similar effects on systemic cytokine levels as control MSCs, suggesting that in vivo at least the initial systemic effect of MSC administration is independent of the level of activity of MSCs, but depends on the response of host cells to MSCs. The results of this study reveal a rapid dose-dependent effect of MSCs and stress the important role of host cells in MSC treatment. This knowledge contributes to the design of rational MSC trials and to the quest for clinical efficacy of MSC therapy.

Multiple doses of adipose tissue-derived mesenchymal stromal cells induce immunosuppression in experimental asthma.

In experimental house dust mite (HDM)‐induced allergic asthma, therapeutic administration of a single dose of adipose tissue‐derived mesenchymal stromal cells (MSCs) ameliorates lung inflammation but is unable to reverse remodeling. We hypothesized that multiple doses of MSCs might exert better therapeutic effects by reducing lung inflammation and remodeling but might also result in immunosuppressive effects in experimental asthma. HDM was administered intranasally in C57BL/6 mice. After the last HDM challenge, mice received two or three doses of MSCs (105 cells per day) or saline intravenously. An additional cohort of mice received dexamethasone as a positive control for immunosuppression. Two and three doses of MSCs reduced lung inflammation, levels of interleukin (IL)‐4, IL‐13, and eotaxin; total leukocyte, CD4+ T‐cell, and eosinophil counts in bronchoalveolar lavage fluid; and total leukocyte counts in bone marrow, spleen, and mediastinal lymph nodes. Two and three doses of MSCs also reduced collagen fiber content and transforming growth factor‐β levels in lung tissue; however, the three‐dose regimen was more effective, and reduced these parameters to control levels, while also decreasing α‐actin content in lung tissue. Two and three doses of MSCs improved lung mechanics. Dexamethasone, two and three doses of MSCs similarly increased galectin levels, but only the three‐dose regimen increased CD39 levels in the thymus. Dexamethasone and the three‐dose, but not the two‐dose regimen, also increased levels of programmed death receptor‐1 and IL‐10, while reducing CD4+CD8low cell percentage in the thymus. In conclusion, multiple doses of MSCs reduced lung inflammation and remodeling while causing immunosuppression in HDM‐induced allergic asthma.

Human mesenchymal stromal cells ameliorate complement induced inflammatory cascade and improve renal functions in a rat model of ischemia-reperfusion induced acute kidney injury.

IntroductionThe primary rational for using mesenchymal stromal cells (MSCs) to rejuvenate damaged tissue is mostly based on their capacity to trans-differentiate and repair injured organs. However, previous studies have demonstrated that MSCs are beneficial even at very early stages, before differentiation and proliferation can be expected. The aim of the current study was to investigate the multifaceted immunological effects of systemically administrating MSCs in the setting of acute kidney injury (AKI) induced by ischemic-reperfusion (I/R).MethodsA rat model of I/R induced AKI was used. The rats underwent a unilateral nephrectomy with simultaneously clamping the contralateral kidney for 60 minutes. Four treatment groups received intravenously, increasing doses of human MSCs and after 48 hours, the rats were sacrificed. Blood was taken to evaluate renal functions and to measure systemic inflammatory markers. Kidneys were taken for histopathologic examinations and evaluations of intra-renal complement activation and inflammatory mediators.ResultsRenal functions improved in U shaped dose dependent manner. Mean serum creatinine levels were 4.5, 2.9, 2.6, 1.7 and 4.1 mg/dL in I/R + placebo, I/R + 150x103 cells, I/R + 250x103 cells, I/R + 500x103 cells and I/R + 1,000x103 cells respectfully (p-values<0.05). Urea demonstrated consistent results with the same U shape improvement manner. The extensive activation of the complement system was ameliorated in the MSCs treatment groups. In addition, MSCs significantly decreased intra-renal levels of IL-1β and TNF-α. It should be noted that the highest doses of MSCs induced renal hypoxia, marked by the Hypoxy-probe staining.ConclusionsThe early beneficial effect of MSCs in the setting of AKI may be attributed to their immunomodulatory effects. Safe treatment with MSCs can block the deleterious activation of the complement cascade and alleviate the hazardous inflammatory mediator-related cascade.