In patients with acute myeloid leukemia (AML), malignant cells modify the properties of multipotent mesenchymal stromal cells (MSCs), reducing their ability to maintain normal hematopoiesis. The aim of this work was to elucidate the role of MSCs in supporting leukemia cells and the restoration of normal hematopoiesis by analyzing ex vivo MSC secretomes at the onset of AML and in remission. The study included MSCs obtained from the bone marrow of 13 AML patients and 21 healthy donors. The analysis of proteins contained in the MSCs-conditioned medium demonstrated that secretomes of patient MSCs differed little between the onset of AML and remission; pronounced differences were observed between MSC secretomes of AML patients and healthy donors. The onset of AML was accompanied by a decrease in the secretion of proteins related to ossification, transport, and immune response. In remission, but not at the onset, secretion of proteins responsible for cell adhesion, immune response, and complement was reduced compared to donors. We conclude that AML causes crucial and, to a large extent, irreversible changes in the secretome of bone marrow MSCs ex vivo. In remission, functions of MSCs remain impaired despite the absence of tumor cells and the formation of benign hematopoietic cells.

Multipotent mesenchymal stromal cells (MSCs) are an object of intense investigation due to their therapeutic potential. MSCs have been well studied in vitro, while their fate after implantation in vivo has been poorly analyzed. We studied the properties of MSCs from the bone marrow (BM-MSC) before and after implantation under the renal capsule using a mini pig model. Autologous BM-MSCs were implanted under the kidney capsule. After 2.5 months, ectopic foci containing bones, foci of ectopic hematopoiesis, bone marrow stromal cells and muscle cells formed. Small pieces of the implant were cultivated as a whole. The cells that migrated out from these implants were cultured, cloned, analyzed and were proven to meet the most of criteria for MSCs, therefore, they are designated as MSCs from the implant—IM-MSCs. The IM-MSC population demonstrated high proliferative potential, similar to BM-MSCs. IM-MSC clones did not respond to adipogenic differentiation inductors: 33% of clones did not differentiate, and 67% differentiated toward an osteogenic lineage. The BM-MSCs revealed functional heterogeneity after implantation under the renal capsule. The BM-MSC population consists of mesenchymal precursor cells of various degrees of differentiation, including stem cells. These newly discovered properties of mini pig BM-MSCs reveal new possibilities in terms of their manipulation.

In patients with acute leukemia (AL), malignant cells and therapy modify the properties of multipotent mesenchymal stromal cells (MSCs) and their descendants, reducing their ability to maintain normal hematopoiesis. The aim of this work was to elucidate the alterations in MSCs at the onset and after therapy in patients with AL. The study included MSCs obtained from the bone marrow of 78 AL patients (42 AML and 36 ALL) and healthy donors. MSC growth characteristics, gene expression pattern, proteome and secretome were studied using appropriate methods. The concentration of MSCs in the bone marrow, proliferative potential, the expression of several genes, proteomes and secretomes were altered in AL-MSCs. Stromal progenitors had been affected differently in ALL and AML patients. In remission, MSC functions remain impaired despite the absence of tumor cells and the maintenance of benign hematopoietic cells. AL causes crucial and, to a large extent, irreversible changes in bone marrow MSCs.

The bone marrow stromal microenvironment is damaged in patients with acute leukemia. The aim of this study was to analyze changes associated with the extracellular matrix, mitochondrial function, and vesicular transport in the proteome of multipotent mesenchymal stromal cells (MSCs) in patients at the onset, in remission, before, and 1–3 months after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The study included paired MSCs samples from the bone marrow of 12 patients at the onset and in remission of acute leukemia (4 ALL, 8 AML) and eight patients before and after allo-HSCT (4 ALL, 4 AML). MSCs from eight healthy donors were used as a control. The growth characteristics and the proteome subsets describing extracellular matrix, mitochondria, and vesicular formation were studied. The proteome of the patients’ MSCs differed significantly from that of the donor MSCs, both at the onset and in remission. Changes noted in the composition of extracellular matrix proteins may affect cell adhesion and access to growth factors. Significant changes were revealed in proteins affecting mitochondrial function. Vesicular transport proteins also differed between the donor and patient groups. Unexpectedly, no differences were found between the MSCs of donors and patients before and after allo-HSCT.

Introduction. During enzyme replacement therapy in patients with Gaucher disease (GD) with recombinant glucocerebrosidase (GCase), regression of bone manifestations is possible, but with prolonged therapy osteonecrosis may occur. These changes may be due to impaired differentiation of multipotent mesenchymal stromal cells (MSCs).Aim: to study changes in the MSCs of healthy donors and a patient with GD when cultured in the presence of GCase.Material and methods. MSCs were isolated from the bone marrow of 17 healthy donors and a female patient with GD by a standard method and cultured in the presence of various concentrations of GCase after the second passage from 2 to 7 weeks. Cell proliferation and the ability to differentiate were analyzed, including after induction. The assessment was carried out by differential staining, elution, and expression of differentiation marker genes by real-time PCR.Results. Low concentrations of recombinant GCase (0.25–1.5 U/ml) did not affect the proliferative activity of MSCs. Prolonged cultivation of MSCs in the presence of low doses of GCase led to a change in the differentiation potential of these cells in the direction of adipogenesis. Concentrations of GCase of 3–5 U/ml inhibited the proliferation of MSCs and caused significant changes in cell differentiation. High doses of the enzyme (7–10 U/ml) had a cytotoxic effect and led to cell death within one passage. The proliferative and differentiation potential of the MSCs of a patient with GD differed significantly from the cells of healthy donors in all the parameters studied.Conclusion. The cultivation of donor MSCs in the presence of recombinant GCase alters the proliferation and differentiation potential of these cells. These changes depend on the dose of the enzyme in the medium and the duration of cultivation.