Publications by authors named "Markus Thomas Rojewski"

Mesenchymal stromal cells (MSCs) are promising therapeutic candidates in a variety of diseases due to having immunomodulatory and pro-regenerative properties. In recent years, MSC-derived small extracellular vesicles (sEVs) have attracted increasing interest as a possible alternative to conventional cell therapy. However, translational processes of sEVs for clinical applications are still impeded by inconsistencies regarding isolation procedures and culture conditions.

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Background: The risk of microbial contamination of cellular products can be reduced when cultured in the presence of antibiotics. This however, may impact the sensitivity of microbiological tests. Given that the addition of antibiotics to cell/tissue products does not guarantee sterility but may just reduce the proliferation rate of microorganisms, microbiological testing of medicinal products remains obligatory.

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Background And Study Aim: Advanced therapy medicinal products (ATMP) frequently lack of clinical data on efficacy to substantiate a future clinical use. This study aims to evaluate the efficacy to heal long bone delayed unions and non-unions, as secondary objective of the EudraCT 2011-005441-13 clinical trial, through clinical and radiological bone consolidation at 3, 6 and 12 months of follow-up, with subgroup analysis of affected bone, gender, tobacco use, and time since the original fracture.

Patients And Methods: Twenty-eight patients were recruited and surgically treated with autologous bone marrow derived mesenchymal stromal cells expanded under Good Manufacturing Practices, combined to bioceramics in the surgical room before implantation.

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Polytrauma (PT) is a life-threatening disease and a major global burden of injury. Mesenchymal stromal cells (MSC) might be a therapeutic option for PT patients due to their anti-inflammatory and regenerative potential. We hypothesised that the inflammatory response of MSC is similar after exposure to selected trauma-relevant factors to sera from PT patients (PTS).

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Article Synopsis
  • - This study explores the translation of a validated pre-clinical protocol for expanding mesenchymal stromal cells (MSCs) into Good Manufacturing Practice (GMP) compliant production for clinical trials, specifically for alveolar bone reconstitution.
  • - Results showed that despite variations in the starting bone marrow material, the standardized manufacturing protocol consistently produced high-quality MSCs within 21 days, meeting all necessary clinical standards.
  • - The findings support the feasibility of using freshly prepared MSCs for bone regeneration in clinical applications, even over long distances between the manufacturing site and the treatment location.
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Background: ORTHO-1 is a European, multicentric, first in human clinical trial to prove safety and feasibility after surgical implantation of commercially available biphasic calcium phosphate bioceramic granules associated during surgery with autologous mesenchymal stromal cells expanded from bone marrow (BM-hMSC) under good manufacturing practices, in patients with long bone pseudarthrosis.

Methods: Twenty-eight patients with femur, tibia or humerus diaphyseal or metaphyso-diaphyseal non-unions were recruited and surgically treated in France, Germany, Italy and Spain with 100 or 200 million BM-hMSC/mL associated with 5-10 cc of bioceramic granules. Patients were followed up during one year.

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Background: Effective therapy of Acute Lung Injury (ALI) is still a major scientific and clinical problem. To define novel therapeutic strategies for sequelae of blunt chest trauma (TxT) like ALI/Acute Respiratory Distress Syndrome, we have investigated the immunomodulatory and regenerative effects of a single dose of ex vivo expanded human or rat mesenchymal stromal cells (hMSCs/rMSCs) with or without priming, immediately after the induction of TxT in Wistar rats.

Methods: We analyzed the histological score of lung injury, the cell count of the broncho alveolar lavage fluid (BAL), the change in local and systemic cytokine level and the recovery of the administered cells 24 h and 5 days post trauma.

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This chapter describes a method for GMP-compliant expansion of human mesenchymal stromal/stem cells (hMSC) from bone marrow aspirates, using the Quantum(®) Cell Expansion System from Terumo BCT. The Quantum system is a functionally closed, automated hollow fiber bioreactor system designed to reproducibly grow cells in either GMP or research laboratory environments. The chapter includes protocols for preparation of media, setup of the Quantum system, coating of the hollow fiber bioreactor, as well as loading, feeding, and harvesting of cells.

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Cell therapy using multipotent mesenchymal stromal cells (MSCs) is of high interest in various indications. As the pleiotropic effects mediated by MSCs rely mostly on their unique secretory profile, long-term persistence of ex-vivo-expanded cells in the recipient may not always be desirable. Irradiation is a routine procedure in transfusion medicine to prevent long-term persistence of nucleated cells and could therefore also be applied to MSCs.

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Simple stress or necrotic cell death with subsequent release of damage-associated molecular patterns (DAMPs) is a characteristic feature of most advanced tumors. DAMPs within the tumor microenvironment stimulate tumor-associated cells, including dendritic cells and mesenchymal stromal cells (MSCs). The presence of tumor-infiltrating MSCs is associated with tumor progression and metastasis.

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Mesenchymal stromal cells (MSCs) are highly interesting candidates for clinical applications in regenerative medicine. Due to their low occurrence in human tissues, extensive in vitro expansion is necessary to obtain sufficient cell numbers applicable as a clinical dose in the context of cellular therapy. Current cell culture media formulations for the isolation and expansion of MSCs include fetal calf serum (FCS), human AB serum (ABS), or human platelet lysate (PL) as a supplement.

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Background Aims: The clinical use of human mesenchymal stromal cells (MSC) requires ex vivo expansion in media containing supplements such as fetal bovine serum or, alternatively, human platelet lysate (PL).

Methods: Platelet concentrates were frozen, quarantine stored, thawed and sterile filtered to obtain PL. PL content and its effect on fibroblast-colony-forming unit (CFU-F) formation, MSC proliferation and large-scale expansion were studied.

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Epidemiological, clinical and post mortem studies indicate that inflammatory and immune reactions are involved in the pathomechanisms of affective and schizophrenic spectrum disorders. However, in psychiatric patients, only sporadic investigation on immunochemistry has been performed and information about immunofunction derived by investigation of immunocompetent cells in the CSF is not available to date. Here we present an interdisciplinary work of neurologists, psychiatrists and hemato-immunologists focusing on the immunology of psychiatric and neurological disorders.

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CD4+CD25+ regulatory T cells (Tregs) can influence various immune responses. Little is known about the effects of the Abl/Src kinase inhibitor dasatinib on Tregs which regulate anti-tumor/leukaemia immune responses. The present study demonstrated that dasatinib inhibited proliferation of Tregs and CD4+CD25- T cells in a dose-dependent manner, which was associated with the decreased production of corresponding cytokines.

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Recent studies suggest inflammatory mechanisms involved in the pathogenesis of major psychiatric disorders (MPD). T cells play a major role during inflammation, but little is known about T cell subpopulations in the cerebrospinal fluid (CSF). We investigated the frequency of cells positive for the surface markers CD4, CD8, CD25, CD45, CD69, and CD127 in 45 paired cerebrospinal fluid (CSF) and peripheral blood (PB) samples by multiparameter flow cytometry from patients with MPD of the schizophrenic and affective spectrum with normal CSF cell counts and compared them with those from patients with non-inflammatory (NIND), chronic inflammatory (CIND) neurological disorders, and meningitis (MEN).

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Objective: To investigate the inhibitory effects of dasatinib on proliferation, function, and signaling events on CD8+T cells.

Materials And Methods: Carboxyfluorescein diacetate succinimidyl ester and 5-bromo-2-deoxyuridine were used to detect proliferation and cell cycle of CD8+T cells treated with dasatinib, respectively. Frequency and function of viral and leukemia-antigen-specific CD8+T cells from healthy donors were measured by tetramer staining and ELISPOT assay.

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SUMMARY: Research on expanded human stem cells has become an increasing field of interest during the last decade. The increasing interest in adult stem cells, especially mesenchymal stem and mesenchymal stromal cells, in hematology and regenerative medicine is also based on the simplicity of isolation and ex vivo expansion of these cells. These processes require an adequate quality control of source and product.

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Arsenic trioxide (As2O3) has a long history of use in medicine. However, it was almost forgotten in Western medicine in the recent centuries. Prompted by reports from China about successful treatment of acute promyelocytic leukemia (APL) with As2O3, there was again increasing interest in this drug in the 1990s.

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The potency of arsenic trioxide (As2O3) as chemotherapeutic agent is under investigation in various clinical trials. As2O3 was shown to be a potent inductor of apoptosis, and several publications describe the involvement of caspases, reduction of mitochondrial membrane potential and modulation of intracellular glutathione level. However, little is known about the involvement of membrane bound cell death receptors.

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Objective: Mitochondrial membrane potential (deltaPsim) and intracellular Ca2+ play a crucial role in growth and differentiation in hemopoiesis. Some potassium channel openers such as diazoxide have the capacity to elevate cytosolic Ca2+ and depolarize mitochondria in cardiomyocytes. To clarify if such substances have effects on hemopoietic cells we investigated the commonly used opener of the mitoK(ATP) channel, diazoxide, and the opener of BK channels, NS1619, for their potential to depolarize mitochondria, elevate cytosolic Ca2+, and induce apoptosis in the hemopoietic CD34+ cell line KG-1a.

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