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

peer reviewedBackground: 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 NCT0444545

The use of mesenchymal stromal cells in solid organ transplantation

peer reviewedOrgan transplantation is the only definitive treatment for many critical diseases of the liver, kidney, heart, pancreas, and lungs. Although it is the primary therapeutic option at present, transplanted patients have to deal with the numerous side effects of life-long dependence on immunosuppressive drugs, and these drugs still fail to prevent chronic rejection of the transplanted organ in many cases. The risk of developing cancer and opportunistic infections is also markedly increased in solid organ transplant (SOT) recipients receiving long-term immunosuppressive therapy. Cancer and opportunistic infections cannot be completely avoided since they result from the immunosuppressive drugs used posttransplant that affect not only the anti-graft response but also the entire immune response. Finding a way to establish donor-specific immunological tolerance without the need for nonspecific immunosuppression remains one of the major goals in transplantation medicine [1,2]. Another important aim is the improvement of graft survival and function. Overall, graft survival is about 15 years, but the increasing shortage of organs has led to the use of expanded criteria for donor organs often donated by older individuals, which are less robust organs than those donated by younger donors. Mesenchymal stromal cell (MSCs) are currently being evaluated in SOT with the hope of achieving more selective immunosuppression, better graft function, and longer graft survival

The role of mesenchymal stromal cells in the treatment of ulcerative colitis and Crohn’s disease

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Mesenchymal stromal cells and organ transplantation

peer reviewedLes cellules stromales mésenchymateuses (CSM) sont des cellules multipotentes et capables d’autorenouvellement. Les CSM semblent intéressantes pour leurs propriétés immunomodulatrices, dans la prévention ou le traitement du traumatisme ischémique, ainsi que dans la potentielle reconstitution ou amélioration d’organes. Depuis quelques années, le rôle potentiel des CSM en transplantation d’organes est évalué par des études in vitro et dans des modèles animaux. Leurs caractéristiques font des CSM une thérapie cellulaire potentielle idéale en transplantation d’organes, et une étude prospective translationnelle, contrôlée, de phase 1-2, a débuté au CHU de Liège : elle vise à évaluer les risques et les bénéfices de l’injection de CSM après transplantation de foie ou de rein. Les résultats préliminaires de cette étude semblent intéressants, mais seule une évaluation approfondie par une étude de phase 3, randomisée, permettra de confirmer l’intérêt théorique des CSM en transplantation d’organe solide.Mesenchymal stromal cells (MSC) are multipotent and self-renewing cells. MSC are studied for their in vivo and in vitro immunomodulatory effects, in the prevention or the treatment of ischemic injury, and for their potential properties of tissue or organ reconstruction. Over the last few years, the potential role of MSC in organ transplantation has been studied both in vitro and in vivo, and their properties make them an ideal potential cell therapy after solid organ transplantation. A prospective, controlled, phase 1-2 study has been initiated at the CHU of Liege, Belgium. This study assesses the potential risks and benefits of MSC infusion after liver or kidney transplantation. Even if the preliminary results of this study look promising, solely a prospective, randomized, large scale, phase 3 study will allow the clinical confirmation of the theoretical benefits of MSC in solid organ transplantation

Umbilical cord mesenchymal stromal cells are superior to bone marrow and adipose tissue-derived mesenchymal stromal cells for the treatment of xenogeneic graft-versus-host disease in mice.

Mesenchymal stromal cell therapy in the context of hematopoietic stem cell transplantatio

Multipotent mesenchymal stromal cell therapy for steroid-refractory acute graft-versus-host disease after allogeneic stem cell transplantation

Steroid-refractory acute graft-versus-host disease is a severe complication after allogeneic stem cell transplantation. So far, its treatment remains very challenging since the current therapies do not offer significant benefits. Among the most recent approaches, multipotent mesenchymal stromal cell-based therapy has attracted great interest over the past decade. Here, we briefly reviewed the current knowledges about the immunomodulatory properties of multipotent mesenchymal stromal cells as well as results of preclinical and clinical studies having assessed their efficacy to modulate steroid-refractory acute graft-versus-host disease

Impact of dust addition on the microbial food web under present and future conditions of pH and temperature

International audienceIn the oligotrophic waters of the Mediterranean Sea, during the stratification period, the microbial loop relies on pulsed inputs of nutrients through the atmospheric deposition of aerosols from both natural (e.g., Saharan dust), anthropogenic, or mixed origins. While the influence of dust deposition on microbial processes and community composition is still not fully constrained, the extent to which future environmental conditions will affect dust inputs and the microbial response is not known. The impact of atmospheric wet dust deposition was studied both under present and future environmental conditions (+3 ∘C warming and acidification of −0.3 pH units), through experiments in 300 L climate reactors. In total, three Saharan dust addition experiments were performed with surface seawater collected from the Tyrrhenian Sea, Ionian Sea, and Algerian basin in the western Mediterranean Sea during the PEACETIME (ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea) cruise in May-June 2017. Top-down controls on bacteria, viral processes, and community, as well as microbial community structure (16S and 18S rDNA amplicon sequencing), were followed over the 3-4 d experiments. Different microbial and viral responses to dust were observed rapidly after addition and were, most of the time, more pronounced when combined with future environmental conditions. The dust input of nutrients and trace metals changed the microbial ecosystem from a bottom-up limited to a top-down controlled bacterial community, likely from grazing and induced lysogeny. The relative abundance of mixotrophic microeukaryotes and phototrophic prokaryotes also increased. Overall, these results suggest that the effect of dust deposition on the microbial loop is dependent on the initial microbial assemblage and metabolic state of the tested water and that predicted warming and acidification will intensify these responses, affecting food web processes and biogeochemical cycles

Impact of dust addition on the microbial food web under present and future conditions of pH and temperature

International audienceIn the oligotrophic waters of the Mediterranean Sea, during the stratification period, the microbial loop relies on pulsed inputs of nutrients through the atmospheric deposition of aerosols from both natural (e.g., Saharan dust), anthropogenic, or mixed origins. While the influence of dust deposition on microbial processes and community composition is still not fully constrained, the extent to which future environmental conditions will affect dust inputs and the microbial response is not known. The impact of atmospheric wet dust deposition was studied both under present and future environmental conditions (+3 ∘C warming and acidification of −0.3 pH units), through experiments in 300 L climate reactors. In total, three Saharan dust addition experiments were performed with surface seawater collected from the Tyrrhenian Sea, Ionian Sea, and Algerian basin in the western Mediterranean Sea during the PEACETIME (ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea) cruise in May-June 2017. Top-down controls on bacteria, viral processes, and community, as well as microbial community structure (16S and 18S rDNA amplicon sequencing), were followed over the 3-4 d experiments. Different microbial and viral responses to dust were observed rapidly after addition and were, most of the time, more pronounced when combined with future environmental conditions. The dust input of nutrients and trace metals changed the microbial ecosystem from a bottom-up limited to a top-down controlled bacterial community, likely from grazing and induced lysogeny. The relative abundance of mixotrophic microeukaryotes and phototrophic prokaryotes also increased. Overall, these results suggest that the effect of dust deposition on the microbial loop is dependent on the initial microbial assemblage and metabolic state of the tested water and that predicted warming and acidification will intensify these responses, affecting food web processes and biogeochemical cycles

Impact of dust addition on the microbial food web under present and future conditions of pH and temperature

International audienceIn the oligotrophic waters of the Mediterranean Sea, during the stratification period, the microbial loop relies on pulsed inputs of nutrients through the atmospheric deposition of aerosols from both natural (e.g., Saharan dust), anthropogenic, or mixed origins. While the influence of dust deposition on microbial processes and community composition is still not fully constrained, the extent to which future environmental conditions will affect dust inputs and the microbial response is not known. The impact of atmospheric wet dust deposition was studied both under present and future environmental conditions (+3 ∘C warming and acidification of −0.3 pH units), through experiments in 300 L climate reactors. In total, three Saharan dust addition experiments were performed with surface seawater collected from the Tyrrhenian Sea, Ionian Sea, and Algerian basin in the western Mediterranean Sea during the PEACETIME (ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea) cruise in May-June 2017. Top-down controls on bacteria, viral processes, and community, as well as microbial community structure (16S and 18S rDNA amplicon sequencing), were followed over the 3-4 d experiments. Different microbial and viral responses to dust were observed rapidly after addition and were, most of the time, more pronounced when combined with future environmental conditions. The dust input of nutrients and trace metals changed the microbial ecosystem from a bottom-up limited to a top-down controlled bacterial community, likely from grazing and induced lysogeny. The relative abundance of mixotrophic microeukaryotes and phototrophic prokaryotes also increased. Overall, these results suggest that the effect of dust deposition on the microbial loop is dependent on the initial microbial assemblage and metabolic state of the tested water and that predicted warming and acidification will intensify these responses, affecting food web processes and biogeochemical cycles