Search Results (154)

The accelerated hydrolytic degradation of poly(L-lactide) (PLA)/magnesium (Mg) composite films was investigated to elucidate the influence of surface modification of Mg particles on the degradation behavior and characteristics of PLA composites. Accelerated degradation studies were conducted at 60 °C in a pH 7.4 phosphate-buffered solution over 7 weeks, with degradation monitored using several techniques: mass loss, water absorption, thermal analysis, and Raman spectroscopy. The results indicated that all composite films experienced more than 90% mass loss at the end of experiment; however, PLA/5MgTT and PLA/5MgPEI exhibited the highest resistance to degradation, likely due to the protective effect of the surface modification induced by thermal treatment and polyethylenimine (PEI). Notably, these characteristics did not compromise the biocompatibility or osteogenic potential of the films, which remained comparable to the control samples when tested on human bone marrow multipotent mesenchymal/stromal cells. Full article

Replicative or stress-induced senescence disrupts the functioning of multipotent mesenchymal stromal cells (MSCs) required for tissue renewal and regeneration. Aged MSCs demonstrate reduced proliferation, impaired differentiation, and aberrant secretory activity, defined as “senescence-associated secretory phenotype” (SASP). SASP is characterized by elevated secretion of proinflammatory cytokines and specific extracellular vesicles (SASP-EVs), which affect the cellular microenvironment and promote tissue dysfunction. However, molecular mechanisms responsible for senescent phenotype propagation remain largely obscure. Earlier, we demonstrated suppression of adipogenic differentiation and insulin sensitivity of young MSCs by SASP-EVs. In this study, we elucidated potential mechanisms underlying SASP-EVs’ effects on MSCs. Bioinformatic analysis revealed that insulin signaling components are the most probable targets of SASP-EVs microRNA cargo. We demonstrated that SASP-EVs downregulated intracellular AGO1 levels, but surprisingly, PTEN levels were upregulated. Specifically, the increase in PTEN content was provided by its nuclear fraction. We have found that the intracellular PTEN distribution in young MSCs treated by SASP-EVs was similar to senescent MSCs. Furthermore, PTEN upregulation was accompanied by increased PTENP1 expression—a molecular sponge for PTEN-targeting microRNAs. Our findings indicate that nuclear PTEN could be a hallmark of senescent MSCs, and SASP-EVs propagate the senescent phenotype in young MSCs by promoting PTEN nuclear localization. Full article

Cell technologies have provided promising tools for modulating the properties of multipotent mesenchymal stem/stromal cells (MSCs) to meet the needs of cell therapy as well as tissue engineering and regenerative medicine (TERM). Ex vivo preconditioning is directed at enhancing the engraftment of MSCs and activating their secretory activity, primarily the production of soluble mediators. The present review aims to highlight the underestimated effect of the most accepted preconditioning approaches on the modification of the important set of insoluble molecules secreted by MSCs into extracellular space—the extracellular matrix (ECM). A thorough review of the published literature was performed, with particular emphasis on ECM-related data. The analysis of data on ECM changes showed that most of the applied preconditioning methods—hypoxia, inflammatory priming, pharmacological agents, 3D culture, and scaffolds—generally stimulate ECM production, increase the deposition of growth factors, promote alignment, and increase ECM stiffness. There are already preliminary results demonstrating the successful application of preconditioned ECM for promoting angiogenesis, targeted stromal lineage differentiation, and other therapeutic goals. The prospects for further research in this area are discussed. Full article

Nanotechnology is transforming contemporary medicine by providing cutting-edge tools for the treatment and diagnosis of complex disorders. Advanced techniques such as bioimaging and photodynamic therapy (PDT) combine early diagnosis and targeted therapy, offering a more precise approach than conventional treatments. However, a significant obstacle for PDT is the need to selectively deliver photosensitizers to disease sites while minimizing systemic side effects. In this context, mesenchymal stem cells have emerged as promising biological carriers due to their natural tropism towards tumors, low immunogenicity, and their ability to overcome biological barriers. In this study, two push–pull compounds, NPI-PTZ and BTZ-PTZ, phenothiazine derivatives featuring aggregation-induced emission (AIE) abilities, were analyzed. These molecules proved to be excellent fluorescent probes and photosensitizing agents. When administered to human bone marrow-derived multipotent stromal cells (hBM-MSCs) and human adipose multipotent stem cells (hASCs), the compounds were efficiently internalized, maintained a stable fluorescent emission for several days, and showed phototoxicity after irradiation, without inducing major cytotoxic effects under normal conditions. These results highlight the potential of NPI-PTZ and BTZ-PTZ combined with mesenchymal stem cells as theranostic tools, bridging bioimaging and PDT, and suggest new possibilities for advanced therapeutic approaches in clinical applications. Full article

Secondary osteonecrosis (ON) is a common complication in paediatric cancer survivors. Combining multipotent mesenchymal stromal cells (MSCs) with core decompression surgery halts disease progression and stimulates bone regeneration. However, the success of advanced therapy medicinal products (ATMPs) requires versatile “off-the-shelf” tissue engineering products (TEPs). This study evaluated the safety and efficacy of TEPs loaded with allogeneic MSCs from Wharton’s jelly (WJ-MSCs) in a large-animal model of bone regeneration to support a paediatric investigational plan for ON patients. WJ-MSC-laden fibrin-based hydrogels combined with a synthetic bone substitute (PRO-DENSE^TM) were tested in 16 juvenile sheep (8 males and 8 females) distributed in four experimental groups. Each animal received four cylindrical bone defects in the femoral and tibial epiphyses and was assessed at 6 and 12 weeks. Safety was confirmed, and bone regeneration was observed across all groups. A combination of WJ-MSCs with PRO-DENSE^TM led to improved histological scores, osteogenesis, and construct integration. Trabecular bone volume also increased more in cellular groups over time. However, effects were inconsistent across groups, reflecting the variability seen in clinical trials and highlighting the significant impact of factors such as immunogenetic compatibility, MSC batch potency, and interaction with the recipient’s microenvironment on the therapeutic effectiveness and successful clinical translation of allogeneic ATMPs. Full article

Background/Objectives: Acute leukemia (AL) alters both hematopoiesis and the bone marrow stromal microenvironment. Attempts to develop a culture of multipotent mesenchymal stromal cells (MSCs) from AL patients’ bone marrow are not always successful, as opposed to healthy donors’ bone marrow. Methods: To unveil the reason, healthy donors’ MSCs were cultured in the presence of sera from healthy donors (control group) or AL patients at the onset of the disease, in short- and long-term remission, and before and after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Results: The cell yield in the presence of patient sera was lower than in the control, regardless of the AL stage. It was assumed that the patients either lacked growth factors to sustain MSCs, or there were inhibitors of MSC growth present. The serum’s ability to support MSC growth correlated with platelet count and albumin and calcium concentrations in patients’ blood. Platelet-derived growth factors—PDGFA and PDGFB—are known to induce MSC growth. Their concentration in the serum of AL patients and healthy donors was analyzed. A decrease in PDGFA concentration was found in the sera of patients compared to healthy donors. PDGFB concentration was lower at disease onset, increased during remission and decreased again during relapse. PDGFB concentration correlated with platelet count, while PDGFA concentration did not. AL patients’ sera reflected systemic disturbances affecting MSC growth. So far, decreases in PDGFs, albumin and calcium concentration, as well as platelet count, are the parameters that might be among the causes of this observation. Full article

The stroma of healthy pancreases contains various non-hematopoietic, non-endothelial mesenchymal cells. It is altered by chronic inflammation which in turn is a major contributor to the development of pancreatic adenocarcinoma (PDAC). In PDAC, the stroma plays a decisive and well-investigated role for tumor progression and therapy response. This review addresses the central role of stromal cells in the early inflammation-driven development of PDAC. It focuses on major subpopulations of pancreatic mesenchymal cells, i.e., fibroblasts, pancreatic stellate cells, and multipotent stroma cells, particularly their activation and functional alterations upon chronic inflammation including the development of different types of carcinoma-associated fibroblasts. In the second part, the current knowledge on the impact of activated stroma cells on acinar-to-ductal metaplasia and the transition to pancreatic intraepithelial neoplasia is summarized. Finally, putative strategies to target stroma cells and their signaling in early pancreatic carcinogenesis are reflected. In summary, the current data show that the activation of pancreatic stroma cells and the resulting fibrotic changes has pro- and anti-carcinogenetic effects but, overall, creates a carcinogenesis-promoting microenvironment. However, this is a dynamic process and the therapeutic targeting of specific pathways and cells requires in-depth knowledge of the molecular interplay of various cell types. Full article

This paper describes an evaluation of the mechanical and biological properties of highly porous, biocompatible poly(lactic-co-glycolic acid) (PLGA) scaffolds produced using the antisolvent 3D printing technique under various forming conditions. The dependence of the scaffolds’ microstructure, PLGA molecular weight distribution, and cell adhesion properties on temperature and injection nozzle diameter was evaluated. All samples consisted of fibers with different inner polymer distributions formed by specific radial, highly porous structures with a mean pore length of less than 50 μm and a diameter below 10 μm. The microstructure formed using a nozzle with a diameter of 160 μm showed a moderate correlation with printing temperature, while for the 330 μm nozzle, there was no significant difference in microstructures formed at different temperatures. Scaffolds produced at lower temperatures of 4 °C with a thin nozzle showed better compression load characteristics in terms of strength. In contrast, a larger nozzle allowed the production of a PLGA structure with improved elasticity. A 10–17% change in the molecular weight of PLGA was observed during printing, but no influence on biological properties was found. All types of PLGA scaffolds tested demonstrated good biocompatibility and promoted cell adhesion compared to the control. Full article

Bone marrow mesenchymal stromal cells (BM-MSCs) are multipotent cells present in bone marrow; they play a crucial role in the process of bone formation. Cellular senescence is defined as a stable state of cell cycle arrest that impairs the functioning of cells. Research has shown that aging triggers a state of senescence in BM-MSCs, leading to a reduced capacity for osteogenic differentiation and the accumulation of senescent cells, which can accelerate the onset of various diseases. Therefore, it is essential to explore mechanisms and strategies for the rejuvenation of senescent BM-MSCs. Senile osteoporosis (SOP) is a metabolic bone disease characterized by reduced bone formation. The senescence of BM-MSCs is considered one of the most important factors in the occurrence and development of SOP. Therefore, the rejuvenation of BM-MSCs for the treatment of SOP represents a promising strategy. This work provides a summary of the functional alterations observed in senescent BM-MSCs and a systematic review of the mechanisms that facilitate the rejuvenation of senescent BM-MSCs. Additionally, we analyze the progress in and the limitations associated with the application of rejuvenated senescent BM-MSCs to treat SOP, with the aim of providing new insights for the prevention and treatment of SOP. Full article

SCAPs (Stem Cells from Apical Papilla), derived from the apex of forming wisdom teeth, extracted from teenagers for orthodontic reasons, belong to the MSCs (Mesenchymal Stromal Cells) family. They have multipotent differentiation capabilities and are a potentially powerful model for investigating strategies of clinical cell therapies. Since autophagy—a regulated self-eating process—was proposed to be essential in osteogenesis, we investigated its involvement in the SCAP model. By using a combination of chemical and genetic approaches to inhibit autophagy, we studied early and late events of osteoblastic differentiation. We showed that blocking the formation of autophagosomes with verteporfin did not induce a dramatic alteration in early osteoblastic differentiation monitored by ALP (alkaline phosphatase) activity. However, blocking the autophagy flux with bafilomycin A1 led to ALP repression. Strikingly, the mineralization process was observed with both compounds, with calcium phosphate (CaP) nodules that remained inside cells under bafilomycin A1 treatment and numerous but smaller CaP nodules after verteporfin treatment. In contrast, deletion of Atg5 or Atg7, two genes involved in the formation of autophagosomes and essential to trigger canonical autophagy, indicated that both genes could be involved differently in the mineralization process with a modification of the ALP activity while final mineralization was not altered. Full article

The present study investigates the influence of nitrosamines and etoposide on mesenchymal stromal cells (MSCs) in a differentiation state- and biological age-dependent manner. The genotoxic effects of the agents on both neonatal and adult stem cell populations after treatment, before, or during the course of differentiation, and the sensitivity of the different MSC types to different concentrations of MNU or etoposide were assessed. Hereby, the multipotent differentiation capacity of MSCs into osteoblasts, adipocytes, and chondrocytes was analyzed. Our findings reveal that while all cell types exhibit DNA damage upon exposure, neonatal CB-USSCs demonstrate enhanced resistance to genotoxic damage compared with their adult counterparts. Moreover, the osteogenic differentiation of MSCs was more susceptible to genotoxic damage, whereas the adipogenic and chondrogenic differentiation potentials did not show any significant changes upon treatment with genotoxin. Furthermore, we emphasize the cell-specific variability in responses to genotoxic damage and the differences in sensitivity and reaction across different cell types, thus advocating the consideration of these variabilities during drug testing and developmental biological research. Full article

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. Full article

Desmoplastic small round cell tumors (DSRCTs) of the gastrointestinal (GI) tract are a rare and highly aggressive variant of soft tissue sarcomas, predominantly affecting the abdominal region. These tumors are believed to originate from multipotent mesenchymal stem cells or primitive progenitor cells. They are composed of small round tumor cells associated with prominent stromal desmoplasia, polyphenotypic differentiation, and EWSR1::WT1 gene fusion. Diagnostically, DSRCTs present a significant challenge due to their histological resemblance to other small round cell tumors, such as Ewing sarcoma and rhabdomyosarcoma, necessitating the use of ancillary tests, including immunopanels and molecular analysis, to reach a definitive diagnosis. Immunohistochemical staining, including markers like cytokeratin, vimentin, desmin, and WT1, has proven valuable in differentiating DSRCTs from their mimickers. The prognosis of these tumors is highly dependent on factors such as tumor location and stage at diagnosis, and given their aggressive nature, a multidisciplinary approach may be required that combines surgical resection, chemotherapy, and radiation therapy, among other options. In this review, we provide a synopsis of the pathophysiology of DSRCTs and the latest diagnostic advancements, including the utility of molecular profiling and novel biomarkers. Full article

Aplastic anemia (AA) is characterized by bone marrow (BM) aplasia and pancytopenia. BM stromal microenvironment is closely intertwined with hematopoietic cells by reciprocal regulation. It is still unclear how hematopoietic deficiency affects the bone marrow stroma of the AA patients. Multipotent mesenchymal stromal cells (MMSCs) are the progenitors of stromal cells. In vitro, proliferation rate of MMSCs of AA patients is decreased compared to those of healthy donors. This may be explained by the influence of pathological environmental condition in the patients’ BM. The aim of the study was to compare the effect of AA patients’ sera on healthy donor MMSCs to healthy donors’ sera and to elucidate the nature of their difference. Proliferation test showed 3-fold decrease in number of MMSCs after incubation in medium supplemented with AA patients’ sera compared to donors’ serum samples. The degree of this effect correlated with the severity of thrombocytopenia in patients. The decrease in cell number was not associated with cell death, as the number of apoptotic cells defined by flow cytometry did not differ between the groups. ELISA revealed a decreased level of PDGF-BB in the patients’ sera compared to donors’ serum samples (69 ± 5 pg/mL vs. 112 ± 21 pg/mL, respectively). The addition of recombinant PDGF-BB or healthy donor’s platelet lysate to the culture medium supplemented with AA patients’ serum restored its ability to support MMSCs growth. Thus, PDGF-BB deficiency is one of the environmental factors causing MMSCs damage in AA patients. Full article

Wound healing in adults largely depends on the functional state of multipotent mesenchymal stromal cells (MSCs). Human fetal tissues at the early stages of development are known to heal quickly with a full-quality restoration of the original structure. The differences in the molecular mechanisms that determine the functional activity of mesodermal cells in fetuses and adults remain virtually unknown. Using two independent human induced pluripotent stem cell (iPSC) lines, we examined the effects of the initial WNT and BMP activation on the differentiation of iPSCs via mesodermal progenitors into MSCs and highlighted the functions of these cells that are altered by the proinflammatory microenvironment. The WNT-induced mesoderm commitment of the iPSCs enhanced the expression of paraxial mesoderm (PM)-specific markers, while the BMP4-primed iPSCs exhibited increased levels of lateral mesoderm (LM)-specific genes. The inflammatory status and migration rate of the isogenic iPSC-derived mesoderm cells were assessed via gene expression analysis and scratch assay under the receptor-dependent activation of the proinflammatory IFN-γ or TNF-α signaling pathway. Reduced IDO1 and ICAM1 expression levels were detected in the WNT- and BMP-induced MSC progenitors compared to the isogenic MSCs in response to stimulation with IFN-γ and TNF-α. The WNT- and BMP-induced MSC progenitors exhibited a higher migration rate than isogenic MSCs upon IFN-γ exposure. The established isogenic cellular model will provide new opportunities to elucidate the mechanisms of regeneration and novel therapeutics for wound healing. Full article