A management model in blood, tissue and cell establishments to ensure rapid and sustainable patient access to advanced therapy medicinal products in Europe.

Blood, tissue and cell establishments (BTCs) stand out in the management of donor selection, procurement and processing of all types of substances of human origin (SoHO). In the last decades, the framework created around BTCs, including hospitals and national health system networks, and their links to research, development and innovation organizations and agencies have spurred their involvement in the study of groundbreaking advanced therapy medicinal products (ATMP). To further improve strategic synergies in the development of ATMPs, it will be required to promote intra- and inter-European collaborations by creating an international network involving BTCs and major stakeholders (i.e., research organizations, hospitals, universities, patient associations, public agencies). This vision is already shared with the European Blood Alliance, the association of non-profit blood establishments, with 26 member states throughout the European Union and European Free Trade Association states. Herein we present and analyze the "BTC for ATMP Development And Manufacture" (BADAM) model, an ethically responsible business model based on the values and missions of BTCs and their commitment to health equity, patient access and education (based on voluntary donation of SoHO to address unmet clinical needs, while contributing to training professionals and scientific literacy of our Society).

Clinical and MRI Evolution After Local Injection of Bone Marrow-Derived Mesenchymal Stem Cells in Perianal Fistulae in Crohn's Disease: Results From a Prospective Monocentric Study.

BACKGROUND: Local injection of adipose tissue-derived mesenchymal stem cells [MSCs] is effective in fistulizing perianal Crohn's disease [CD]. Less is known about bone marrow-derived MSCs and little is known about predictive factors of response and magnetic resonance imaging [MRI] evolution of the fistulae after MSC injection. Our aims were to evaluate the safety and clinical outcome of bone marrow-derived MSC injection for perianal fistulizing CD, to evaluate the MRI evolution of the fistulae and to identify factors associated with fistula closure. PATIENTS AND METHODS: All CD patients with perianal fistula and appropriate drainage with a seton without abscess at MRI were eligible. Clinical examination, biomarkers and pelvic MRI were performed at weeks 0, 12 and 48. The clinical outcome was assessed by closure of the treated external openings at clinical examination and MRI exploration. RESULTS: Sixteen patients with a median age of 49 years and a median duration of perianal CD of 8 months were included. No unexpected safety event occurred. At weeks 12 and 48, 9/16 and 8/16 patients had complete fistula[e] closure, respectively, whereas 11/16 patients had at least partial closure. At MRI, the degree of fibrosis increased significantly after MSC injection. In total, 86% of patients with >80% of fibrosis of the fistula tract at week 48 had fistula closure. Fistula closure at week 12 was predictive of fistula closure at week 48. The MAGNIFI-CD did not change significantly over time. CONCLUSION: Open-label injection of bone marrow-derived MSCs was safe and was effective in half of the patients in fistulizing perianal CD and induced significant MRI changes associated with favourable clinical outcome.

Multipotent mesenchymal stromal cells as treatment for poor graft function after allogeneic hematopoietic cell transplantation: A multicenter prospective analysis.

Introduction: Poor graft function (PGF) is a rare but serious complication of allogeneic hematopoietic cell transplantation (alloHCT). Due to their hematopoietic supporting properties and immune regulatory effects, multipotent mesenchymal stromal cells (MSC) could be considered a good candidate to help to restore bone marrow (BM) niches homeostasis and facilitate hematopoiesis after alloHCT. Methods: We prospectively assessed the efficacy and safety of ex-vivo expanded BM-derived MSC from third-party donor in a series of 30 patients with prolonged severe cytopenia and PGF after alloHCT. This multicenter trial was registered at www.clinicaltrials.gov (#NTC00603330). Results: Within 90 days post-MSC infusion, 53% (95% CI, 35 - 71%) of patients improved at least one cytopenia (overall response, OR) and 37% (95% CI, 19 - 54%) achieved a complete hematological response (CR: absolute neutrophil count, ANC >0.5 x 109/L, Hb > 80g/L and platelet count > 20 x 109/L with transfusion independence). Corresponding response rates increased to 67% (95% CI, 50 - 84%) OR and 53% (95% CI, 35 - 71%) CR within 180 days after MSC infusion. A significant decrease in red blood cells and platelets transfusion requirement was observed after MSC (median of 30-days transfusion requirement of 0.5 and 0 from d90-120 post-MSC versus 5 and 6.5 before MSC, respectively, p ≤0.001). An increase in ANC was also noted by day +90 and +180, with 3/5 patients with severe neutropenia having recovered an ANC > 1 x 109/L within the 90-120 days after MSC infusion. Overall survival at 1 year post-MSC was 70% (95% CI, 55.4 - 88.5), with all but one of the patients who achieved CR being alive. A single infusion of third-party MSC appeared to be safe, with the exception of one deep vein thrombotic event possibly related to the intervention. Discussion: In conclusion, a single i.v. infusion of BM-derived MSC from third party donor seemed to improve hematological function after alloHCT, although spontaneous amelioration cannot be excluded. Comparative studies are warranted to confirm these encouraging results.

Bone Marrow-Derived Mesenchymal Stromal Cell Therapy in Severe COVID-19: Preliminary Results of a Phase I/II Clinical Trial.

Background: Treatment of acute respiratory distress syndrome (ARDS) associated with COronaVIrus Disease-2019 (COVID-19) currently relies on dexamethasone and supportive mechanical ventilation, and remains associated with high mortality. Given their ability to limit inflammation, induce immune cells into a regulatory phenotype and stimulate tissue repair, mesenchymal stromal cells (MSCs) represent a promising therapy for severe and critical COVID-19 disease, which is associated with an uncontrolled immune-mediated inflammatory response. Methods: In this phase I-II trial, we aimed to evaluate the safety and efficacy of 3 intravenous infusions of bone marrow (BM)-derived MSCs at 3-day intervals in patients with severe COVID-19. All patients also received dexamethasone and standard supportive therapy. Between June 2020 and September 2021, 8 intensive care unit patients requiring supplemental oxygen (high-flow nasal oxygen in 7 patients, invasive mechanical ventilation in 1 patient) were treated with BM-MSCs. We retrospectively compared the outcomes of these MSC-treated patients with those of 24 matched control patients. Groups were compared by paired statistical tests. Results: MSC infusions were well tolerated, and no adverse effect related to MSC infusions were reported (one patient had an ischemic stroke related to aortic endocarditis). Overall, 3 patients required invasive mechanical ventilation, including one who required extracorporeal membrane oxygenation, but all patients ultimately had a favorable outcome. Survival was significantly higher in the MSC group, both at 28 and 60 days (100% vs 79.2%, p = 0.025 and 100% vs 70.8%, p = 0.0082, respectively), while no significant difference was observed in the need for mechanical ventilation nor in the number of invasive ventilation-free days, high flow nasal oxygenation-free days, oxygen support-free days and ICU-free days. MSC-treated patients also had a significantly lower day-7 D-dimer value compared to control patients (median 821.0 µg/L [IQR 362.0-1305.0] vs 3553 µg/L [IQR 1155.0-6433.5], p = 0.0085). Conclusions: BM-MSC therapy is safe and shows very promising efficacy in severe COVID-19, with a higher survival in our MSC cohort compared to matched control patients. These observations need to be confirmed in a randomized controlled trial designed to demonstrate the efficacy of BM-MSCs in COVID-19 ARDS. Clinical Trial Registration: (www.ClinicalTrials.gov), identifier NCT04445454.

Mesenchymal Stem Cell Injection in Crohn's Disease Strictures: A Phase I-II Clinical Study.

BACKGROUND AND AIM: Mesenchymal stem cells [MSCs] have anti-inflammatory and anti-fibrotic properties and could be a potential therapy for Crohn's disease [CD] strictures. In this phase I-II pilot trial, we assessed safety and efficacy of local MSC injection to treat CD strictures. METHODS: CD patients with a short [less than 5 cm in length] non-passable stricture accessible by ileocolonoscopy were included. Allogenic bone-marrow derived MSCs were injected in the four quadrants of the stricture. Adverse events and clinical scores were evaluated at each follow-up visit and endoscopy and magnetic resonance enterography were performed at baseline, Week [W]12 and W48. The main judgement criterion for efficacy was the complete [defined by the ability to pass the ileocolonoscope] or partial [defined by a diameter increase] resolution of the stricture at W12. Second efficacy criteria included assessment of the stricture at W48 and evolution of clinical scores at W12 and W48. RESULTS: We performed 11 MSC injections in 10 CD patients [three primary and seven anastomotic strictures; one stricture injected twice]. MSC injections were well tolerated but four hospitalisations for occlusion were reported. At W12, five patients presented a complete or partial resolution of the stricture [two complete and three partial]. Seven patients were re-evaluated at W48 [one dilated, one operated, and one lost to follow-up] and four patients had a complete resolution. The evolution of clinical scores between W0, W12, and W48 was not statistically significant. CONCLUSIONS: MSCs injection in CD stricture was well tolerated and may offer a benefit.

Infusion of Allogeneic Mesenchymal Stromal Cells After Liver Transplantation: A 5-Year Follow-Up.

Various properties of mesenchymal stromal cells (MSCs) might be particularly of interest after liver transplantation (LT). In this article, we report the long-term results of a prospective, controlled, and first-in-human phase 1 study evaluating the safety of a single MSC infusion after LT. A total of 10 LT recipients treated with standard immunosuppression received 1.5 to 3 × 106 /kg third-party unrelated MSCs on postoperative day 3 and were prospectively compared with a control group of 10 LT recipients. Primary endpoints were set to prospectively detect potentially delayed adverse effects of MSC infusion, particularly the occurrence of infections and cancers. Secondary endpoints of liver graft and patient survival, graft rejection and function, occurrence of bile duct complications, and development of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) against liver or MSC donors were studied. The median follow-up was 85 months. There was no difference in overall rates of infection or cancer at 5 years of follow-up between the 2 groups. There was also no difference in secondary endpoints. The prevalence of de novo liver DSAs related to HLA mismatches was twice as high in the MSC group compared with the control group. All of the de novo class II HLA antibodies against MSCs were linked to a shared HLA mismatch between the liver and MSCs. This study confirms the safety of a single MSC infusion after LT. The potential benefits of MSC injections in the context of organ transplantation have yet to be demonstrated by larger prospective studies. The development of anti-HLA antibodies against an MSC donor should be further evaluated, especially in cases of shared HLA mismatches between graft and MSC donors, despite the fact that no deleterious effect has been detected.

Influence of Glucocorticoids on Cellular Senescence Hallmarks in Osteoarthritic Fibroblast-like Synoviocytes.

Osteoarthritis (OA) is recognized as being a cellular senescence-linked disease. Intra-articular injections of glucocorticoids (GC) are frequently used in knee OA to treat synovial effusion but face controversies about toxicity. We investigated the influence of GC on cellular senescence hallmarks and senescence induction in fibroblast-like synoviocytes (FLS) from OA patients and mesenchymal stem cells (MSC). METHODS: Cellular senescence was assessed via the proliferation rate, ß-galactosidase staining, DNA damage and CKI expression (p21, p16INK4A). Experimental senescence was induced by irradiation. RESULTS: The GC prednisolone did not induce an apparent senescence phenotype in FLS, with even higher proliferation, no accumulation of ß-galactosidase-positive cells nor DNA damage and reduction in p21mRNA, only showing the enhancement of p16INK4A. Prednisolone did not modify experimental senescence induction in FLS, with no modulation of any senescence parameters. Moreover, prednisolone did not induce a senescence phenotype in MSC: despite high ß-galactosidase-positive cells, no reduction in proliferation, no DNA damage and no CKI enhancement was observed. CONCLUSIONS: We provide reassuring in vitro data about the use of GC regarding cellular senescence involvement in OA: the GC prednisolone did not induce a senescent phenotype in OA FLS (the proliferation ratio was even higher) and in MSC and did not worsen cellular senescence establishment.

MSC Manufacturing for Academic Clinical Trials: From a Clinical-Grade to a Full GMP-Compliant Process.

Following European regulation 1394/2007, mesenchymal stromal cell (MSCs) have become an advanced therapy medicinal product (ATMP) that must be produced following the good manufacturing practice (GMP) standards. We describe the upgrade of our existing clinical-grade MSC manufacturing process to obtain GMP certification. Staff organization, premises/equipment qualification and monitoring, raw materials management, starting materials, technical manufacturing processes, quality controls, and the release, thawing and infusion were substantially reorganized. Numerous studies have been carried out to validate cultures and demonstrate the short-term stability of fresh or thawed products, as well their stability during long-term storage. Detailed results of media simulation tests, validation runs and early MSC batches are presented. We also report the validation of a new variant of the process aiming to prepare fresh MSCs for the treatment of specific lesions of Crohn's disease by local injection. In conclusion, we have successfully ensured the adaptation of our clinical-grade MSC production process to the GMP requirements. The GMP manufacturing of MSC products is feasible in the academic setting for a limited number of batches with a significant cost increase, but moving to large-scale production necessary for phase III trials would require the involvement of industrial partners.

Did Osteoblastic Cell Therapy Improve the Prognosis of Pre-fracture Osteonecrosis of the Femoral Head? A Randomized, Controlled Trial.

BACKGROUND: In patients with nontraumatic osteonecrosis of the femoral head (ONFH), implantation of bone marrow aspirate concentrate (BMAC) could delay the progression of osteonecrosis and improve symptoms in pre-fracture ONFH. However, the BMAC content, especially in osteoblastic stem cells, could have an important individual variability. An autologous osteoblastic cell product could improve the effect of such cell-based therapy. QUESTIONS/PURPOSES: (1) Does autologous osteoblastic cell therapy decrease the likelihood of progression to subchondral fracture with or without early collapse corresponding to Association Research Circulation Osseous (ARCO) classification Stage III or higher, and provide a clinically important pain improvement compared with BMAC treatment alone? (2) Were patients treated with osteoblastic cell therapy less likely to undergo subsequent THA? (3) What proportion of patients in the treatment and control groups experienced adverse events after surgery? METHODS: Between 2004 and 2011, we treated 279 patients for Stage I to II hip osteonecrosis (ON) with surgery. During that time, our general indications for surgery in this setting included non-fracture ON lesions. To be eligible for this randomized, single-blind trial, patients needed to have an ONFH Stage I or II; we excluded those with traumatic ONFH, hemoglobinopathies and positive serology for hepatitis B, C or HIV. Of those treated surgically for this diagnosis during the study period, 24% (67) agreed to participate in this randomized trial. Hips with pre-fracture ONFH were randomly treated with a core decompression procedure associated with either implantation of a BMAC (BMAC group; n = 26) or osteoblastic cell (osteoblastic cell group; n = 30). The groups were not different in terms of clinical and imaging characteristics. The primary study outcome was treatment response, defined as the absence of progression to subchondral fracture stage (ARCO stage III or higher) plus a clinically important pain improvement defined as 1 cm on a 10-cm VAS. The secondary endpoint of interest was the frequency in each group of subsequent THA and the frequency of adverse events. The follow-up duration was 36 months. We used an as-treated analysis (rather than intention-to-treat) for our efficacy endpoint, and an intention-to-treat analysis for adverse events. Overall, 26 of 26 patients in the BMAC group and 27 of 30 in the osteoblastic cell group completed the trial. RESULTS: At 36 months, no clinically important differences were found in any study endpoint. There was no difference in the proportion of patients who had progressed to fracture (ARCO stage III or higher; 46% of the BMAC hips [12 of 26] versus 22% in the hips with osteoblastic cells [six of 27], hazard ratio, 0.47 [95% CI 0.17 to 1.31]; p = 0.15). There was no clinically important difference in VAS pain scores. No differences were found for either the WOMAC or the Lequesne indexes. With the numbers available, there was no difference in the proportion of patients in the groups who underwent THA at 36 months 15% (four of 27) with osteoblastic cells versus 35% (nine of 26) with BMAC; p = 0.09 With the numbers available, we found no differences between the treatment and control groups in terms of the frequencies of major adverse events. CONCLUSIONS: We found no benefit to osteoblastic cells over BMAC in patients with pre-collapse ONFH; side effects were uncommon and generally mild in both groups. This study could be used as pilot data to help determine sample sizes for larger (presumably multicenter) randomized controlled trials. However, this novel treatment cannot be recommended in routine practice until future, larger studies demonstrate efficacy. LEVEL OF EVIDENCE: Level II, therapeutic study.

Mesenchymal Stromal Cells in Solid Organ Transplantation.

Over the past decade, the clinical application of mesenchymal stromal cells (MSCs) has generated growing enthusiasm as an innovative cell-based approach in solid organ transplantation (SOT). These expectations arise from a significant number of both transplant- and non-transplant-related experimental studies investigating the complex anti-inflammatory, immunomodulatory, and tissue-repair properties of MSCs. Promising preclinical results have prompted clinical trials using MSC-based therapy in SOT. In the present review, the general properties of MSCs are summarized, with a particular emphasis on MSC-mediated impact on the immune system and in the ischemic conditioning strategy. Next, we chronologically detail all clinical trials using MSCs in the field of SOT. Finally, we envision the challenges and perspectives of MSC-based cell therapy in SOT.

Comparison of Mesenchymal Stromal Cells From Different Origins for the Treatment of Graft-vs.-Host-Disease in a Humanized Mouse Model.

Mesenchymal stromal cells (MSCs) have potent immunomodulatory properties that make them an attractive tool against graft- vs.-host disease (GVHD). However, despite promising results in phase I/II studies, bone marrow (BM-) derived MSCs failed to demonstrate their superiority over placebo in the sole phase III trial reported thus far. MSCs from different tissue origins display different characteristics, but their therapeutic benefits have never been directly compared in GVHD. Here, we compared the impact of BM-, umbilical cord (UC-), and adipose-tissue (AT-) derived MSCs on T-cell function in vitro and assessed their efficacy for the treatment of GVHD induced by injection of human peripheral blood mononuclear cells in NOD-scid IL-2Rγnull HLA-A2/HHD mice. In vitro, resting BM- and AT-MSCs were more potent than UC-MSCs to inhibit lymphocyte proliferation, whereas UC- and AT-MSCs induced a higher regulatory T-cell (CD4+CD25+FoxP3+)/T helper 17 ratio. Interestingly, AT-MSCs and UC-MSCs activated the coagulation pathway at a higher level than BM-MSCs. In vivo, AT-MSC infusions were complicated by sudden death in 4 of 16 animals, precluding an analysis of their efficacy. Intravenous MSC infusions (UC- or BM- combined) failed to significantly increase overall survival (OS) in an analysis combining data from 80 mice (hazard ratio [HR] = 0.59, 95% confidence interval [CI] 0.32-1.08, P = 0.087). In a sensitivity analysis we also compared OS in control vs. each MSC group separately. The results for the BM-MSC vs. control comparison was HR = 0.63 (95% CI 0.30-1.34, P = 0.24) while the figures for the UC-MSC vs. control comparison was HR = 0.56 (95% CI 0.28-1.10, P = 0.09). Altogether, these results suggest that MSCs from various origins have different effects on immune cells in vitro and in vivo. However, none significantly prevented death from GVHD. Finally, our data suggest that the safety profile of AT-MSC and UC-MSC need to be closely monitored given their pro-coagulant activities in vitro.

Infusion of third-party mesenchymal stromal cells after kidney transplantation: a phase I-II, open-label, clinical study.

Mesenchymal stromal cells (MSCs) exhibit anti-inflammatory and immune-regulatory properties, and preclinical studies suggest a potential benefit in solid organ transplantation. We report on the 1-year follow-up of an open-label phase I-II trial of a single infusion of third-party MSC post-kidney transplantation, in addition to standard immunosuppression. Ten kidney transplant recipients from deceased donors received third-party bone marrow MSCs (∼2 × 106/kg) on day 3 ± 2 post-transplant and were compared to 10 concurrent controls. No adverse effects were noted at MSC injection. One participant with a history of cardiac disease had a non-ST-elevation myocardial infarction approximately 3 hours after MSC infusion. Incidences of opportunistic infections and acute rejection were similar. At day 7 post-transplant, estimated glomerular filtration rate (eGFR) in MSC-treated recipients reached 48.6 ml/min/1.73m2, compared to 32.5 ml/min/1.73m2 in controls and 29.3 ml/min/1.73m2 in our overall cohort of kidney transplant recipients. No difference in eGFR was found at 1 year. MSC-treated recipients showed increased frequencies of regulatory T cells at day 30, with no significant change in B cell frequencies compared to concurrent controls. Four MSC-treated participants developed antibodies against MSC or shared kidney-MSC HLA, with only 1 with MFI >1500. A single infusion of third-party MSC following kidney transplantation appears to be safe, with one cardiac event of unclear relationship to the intervention. MSC therapy is associated with increased regulatory T cell proportion and with improved early allograft function. Long-term effects, including potential immunization against MSC, remain to be studied.

Infusion of bone marrow derived multipotent mesenchymal stromal cells for the treatment of steroid-refractory acute graft-versus-host disease: a multicenter prospective study.

The prognosis of steroid-refractory acute graft-versus-host disease (aGVHD) remains poor and better treatments are urgently needed. Multipotent mesenchymal stromal cell (MSC)-based therapy emerged as a promising approach but response rates were highly variable across studies. We conducted a multicenter prospective study assessing the efficacy of 1-2 infusion(s) of cryopreserved, third-party donor bone marrow-derived MSCs for treating grade II-IV steroid-refractory or -dependent aGVHD in a series of 33 patients. MSCs were produced centrally and distributed to 8 hospitals throughout Belgium to be infused in 2 consecutive cohorts of patients receiving 1-2 or 3-4 × 106 MSCs/kg per dose, respectively. All patients received MSCs as the first rescue therapy after corticosteroids, with the exception for one patient who received prior treatment with mycophenolate mofetil (that was still ongoing by the time of MSC therapy). In these conditions, MSC therapy resulted in at least a partial response in 13 patients (40.6%) at day 30 and in 15 patients (46%) within 90 days after first MSC infusion. The corresponding complete response rates were 21.6% (7 patients) and 30% (10 patients), respectively. Only 5 patients achieved a sustained complete response, lasting for at least 1 month. The 1-year overall survival was 18.2% (95% CI: 8.82-37.5%). Higher response and survival rates were observed among patients receiving 3-4 × 106 MSCs/kg for first infusion, as compared with patients receiving 1-2 × 106 MSCs/ kg. Response and survival with MSC therapy for SR/SD-aGVHD remains to be optimized.

Infusion of mesenchymal stromal cells after deceased liver transplantation: A phase I-II, open-label, clinical study.

BACKGROUND & AIMS: Mesenchymal stromal cell (MSC) infusion could be a means to establish tolerance in solid organ recipients. The aim of this prospective, controlled, phase I study was to evaluate the feasibility, safety and tolerability of a single infusion of MSCs in liver transplant recipients. METHODS: Ten liver transplant recipients under standard immunosuppression received 1.5-3×106/kg third-party unrelated MSCs on postoperative day 3±2, and were prospectively compared to a control group of ten liver transplant recipients. As primary endpoints, MSC infusion toxicity was evaluated, and infectious and cancerous complications were prospectively recorded until month 12 in both groups. As secondary endpoints, rejection rate, month-6 graft biopsies, and peripheral blood lymphocyte phenotyping were compared. Progressive immunosuppression weaning was attempted from month 6 to 12 in MSC recipients. RESULTS: No variation in vital parameters or cytokine release syndrome could be detected during and after MSC infusion. No patient developed impairment of organ functions (including liver graft function) following MSC infusion. No increased rate of opportunistic infection or de novo cancer was detected. As secondary endpoints, there was no difference in overall rates of rejection or graft survival. Month-6 biopsies did not demonstrate a difference between groups in the evaluation of rejection according to the Banff criteria, in the fibrosis score or in immunohistochemistry (including Tregs). No difference in peripheral blood lymphocyte typing could be detected. The immunosuppression weaning in MSC recipients was not successful. CONCLUSIONS: No side effect of MSC infusion at day 3 after liver transplant could be detected, but this infusion did not promote tolerance. This study opens the way for further MSC or Treg-based trials in liver transplant recipients. LAY SUMMARY: Therapy with mesenchymal stromal cells (MSCs) has been proposed as a means to improve results of solid organ transplantation. One of the potential MSC role could be to induce tolerance after liver transplantation, i.e. allowing the cessation of several medications with severe side effects. This study is the first-in-man use of MSC therapy in ten liver transplant recipients. This study did not show toxicity after a single MSC infusion but it was not sufficient to allow withdrawal of immunosuppression. CLINICAL TRIAL REGISTRATION NUMBER: Eudract: # 2011-001822-81, ClinicalTrials.gov: # NCT 01429038.

Clinical-scale expansion of mesenchymal stromal cells: a large banking experience.

BACKGROUND: Mesenchymal stromal cells (MSC) are largely investigated in clinical trials aiming to control inappropriate immune reactions (GVHD, Crohn's disease, solid organ transplantation). As the percentage of MSC precursors in bone marrow is very low, these must be expanded in vitro to obtain therapeutic cell doses. We describe here the constitution of an allogeneic human third-party MSC bank from screened healthy volunteer donors in compliance with quality specifications and ISCT-release criteria and report follow-up of different aspects of this activity since 2007. METHODS: 68 clinical-grade large-scale MSC cultures were completed and analyzed. The whole process was described, including volunteer donor screening, bone marrow collection, mononuclear cell isolation and expansion over 4 weeks, harvesting, cryopreservation, release, administration and quality controls of the cells (including microbiology, phenotype, and potency assays). RESULTS: From 59 validated donors, 68 cultures were completed (mean of final yields: 886 × 10(6) cells/culture) and a total of 464 MSC aliquots have been produced and stored in liquid nitrogen (mean of 132.8 × 10(6) cells/bag). Each MSC batch underwent extensive testing to verify its conformity with EBMT and ISCT release criteria and was individually validated. As of June 1 2015, 314 bags have been released and infused to patients included in 6 different clinical protocols. All thawed MSC units satisfied to release criteria and no infusion-related toxicity was reported. CONCLUSION: In conclusion, despite low passage cultures, we have been able to create an allogeneic "off-the-shelf" MSC bank with a large number of frozen aliquots and report here an efficient clinical-grade MSC banking activity in place for more than 7 years. Our challenge now is to produce MSC in compliance with good manufacturing practices (GMP) as, in the meantime, MSC have become considered as advanced therapy medicinal products (ATMP). Another significant challenge remains the development of relevant potency assay.

Mesenchymal Stromal Cell Therapy in Ischemia/Reperfusion Injury.

Ischemia/reperfusion injury (IRI) represents a worldwide public health issue of increasing incidence. IRI may virtually affect all organs and tissues and is associated with significant morbidity and mortality. Particularly, the duration of blood supply deprivation has been recognized as a critical factor in stroke, hemorrhagic shock, or myocardial infarction, as well as in solid organ transplantation (SOT). Pathophysiologically, IRI causes multiple cellular and tissular metabolic and architectural changes. Furthermore, the reperfusion of ischemic tissues induces both local and systemic inflammation. In the particular field of SOT, IRI is an unavoidable event, which conditions both short- and long-term outcomes of graft function and survival. Clinically, the treatment of patients with IRI mostly relies on supportive maneuvers since no specific target-oriented therapy has been validated thus far. In the present review, we summarize the current literature on mesenchymal stromal cells (MSC) and their potential use as cell therapy in IRI. MSC have demonstrated immunomodulatory, anti-inflammatory, and tissue repair properties in rodent studies and in preliminary clinical trials, which may open novel avenues in the management of IRI and SOT.

Rationale for the potential use of mesenchymal stromal cells in liver transplantation.

Mesenchymal stromal cells (MSCs) are multipotent and self-renewing cells that reside essentially in the bone marrow as a non-hematopoietic cell population, but may also be isolated from the connective tissues of most organs. MSCs represent a heterogeneous population of adult, fibroblast-like cells characterized by their ability to differentiate into tissues of mesodermal lineages including adipocytes, chondrocytes and osteocytes. For several years now, MSCs have been evaluated for their in vivo and in vitro immunomodulatory and 'tissue reconstruction' properties, which could make them interesting in various clinical settings, and particularly in organ transplantation. This paper aims to review current knowledge on the properties of MSCs and their use in pre-clinical and clinical studies in solid organ transplantation, and particularly in the field of liver transplantation. The first available clinical data seem to show that MSCs are safe to use, at least in the medium-term, but more time is needed to evaluate the potential adverse effects of long-term use. Many issues must be resolved on the correct use of MSCs. Intensive in vitro and pre-clinical research are the keys to a better understanding of the way that MSCs act, and to eventually lead to clinical success.

RETRACTED: Human bone marrow, umbilical cord or liver mesenchymal stromal cells fail to improve liver function in a model of CCl4-induced liver damage in NOD/SCID/IL-2Rγ(null) mice.

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been removed at the request of the Editor in Chief. This retraction comes after a thorough investigation of the scientific research presented in the article, along with an investigation into the authorship of the article and the ownership of the data presented. The Editor in Chief's decision to retract the article is based upon the authors' misuse and misrepresentation of a peer's scientific data without consent or approval.

Impact of cotransplantation of mesenchymal stem cells on lung function after unrelated allogeneic hematopoietic stem cell transplantation following non-myeloablative conditioning.

BACKGROUND: In the context of hematopoietic stem cell transplantation (HSCT), mesenchymal stem cells (MSC) have been used to promote engraftment and prevent graft-versus-host disease. However, in animal models, MSC were shown to cause pulmonary alterations after systemic administration. The impact of MSC infusion on lung function has not been studied in humans. The objective of the study was to investigate the impact of MSC co-infusion on lung function and airway inflammation as well as on the incidence of pulmonary infections and cytomegalovirus (CMV) reactivation after HSCT. METHODS: We have prospectively followed 30 patients who underwent unrelated HSCT with MSC co-infusion after non-myeloablative conditioning (NMA). Each patient underwent detailed lung function testing (FEV1, FVC, FEV1/FVC, RV, TLC, DLCO, and KCO) and measurement of exhaled nitric oxide before HSCT and 3, 6, and 12 months posttransplant. The incidence of pulmonary infections and CMV reactivation were also monitored. This group was compared with another group of 28 patients who underwent the same type of transplantation but without MSC co-infusion. RESULTS: Lung function tests did not show important modifications over time and did not differ between the MSC and control groups. There was a higher 1-year incidence of infection, particularly of fungal infections, in patients having received a MSC co-infusion. There was no difference between groups regarding the 1-year incidence of CMV reactivation. CONCLUSIONS: MSC co-infusion does not induce pulmonary deterioration 1 year after HSCT with NMA conditioning. MSC appear to be safe for the lung, but close monitoring of pulmonary infections remains essential.