Search Results (1,019)

Bone integrity is maintained through continuous remodeling, orchestrated by the coordinated actions of osteocytes, osteoblasts, and osteoclasts. Once considered passive bystanders, osteocytes are now recognized as central regulators of this process, mediating biochemical signaling and mechanotransduction. Malfunctioning osteocytes contribute to serious skeletal disorders such as osteoporosis. Mesenchymal stromal cells (MSCs), multipotent stem cells capable of differentiating into osteoblasts, have emerged as promising agents for bone regeneration, primarily through the paracrine effects of their secreted exosomes. MSC-derived exosomes are nanoscale vesicles enriched with proteins, lipids, and nucleic acids that promote intercellular communication, osteoblast proliferation and differentiation, and angiogenesis. Notably, they deliver osteoinductive microRNAs (miRNAs) that influence osteogenic markers and support bone tissue repair. In vivo investigations validate their capacity to enhance bone regeneration, increase bone volume, and improve biomechanical strength. Additionally, MSC-derived exosomes regulate the immune response, creating pro-osteogenic and pro-angiogenic factors, boosting their therapeutic efficacy. Due to their cell-free characteristics, MSC-derived exosomes offer benefits such as diminished immunogenicity and minimal risk of off-target effects. These properties position them as promising and innovative approaches for bone regeneration, integrating immunomodulatory effects with tissue-specific regenerative capabilities. Full article

Epicardial mesothelial cells (EMCs), which form the epicardium, play a crucial role in cardiac homeostasis and repair. Upon damage, EMCs reactivate embryonic development programs, contributing to wound healing, progenitor cell amplification, and regulation of lymphangiogenesis, angiogenesis, and fibrosis. However, the mechanisms governing EMC activation and subsequent regulation remain poorly understood. We hypothesized that hepatocyte growth factor (HGF), a pleiotropic regulator of various cellular functions, could modulate EMC activity. To verify this hypothesis, we developed HGF-overexpressing mesenchymal stromal cell sheets (HGF-MSC CSs) and evaluated their effects on EMCs in vitro and in vivo. This study has revealed, for the first time, that EMCs express the c-Met (HGF receptor) on their surface and that both recombinant HGF and HGF-MSC CSs secretome cause c-Met phosphorylation, triggering downstream intracellular signaling. Our findings demonstrate that the HGF-MSC CSs secretome promotes cell survival under hypoxic conditions by modulating the level of autophagy. At the same time, HGF-MSC CSs stimulate EMC proliferation, promoting their amplification in the damage zone. These data demonstrate that HGF-MSC CSs can be considered a promising regulator of epicardial cell activity involved in heart repair after ischemic damage. Full article

In recent years, significant progress has been made in breast reconstructive surgery, particularly with the use of three-dimensional (3D) disassemblable scaffolds. Reconstructive plastic surgery aimed at restoring the shape and size of the mammary gland offers medical, psychological, and social benefits. Using autologous tissues allows surgeons to recreate the appearance of the mammary gland and achieve tactile sensations similar to those of a healthy organ while minimizing the risks associated with implants; 3D disassemblable scaffolds are a promising solution that overcomes the limitations of traditional methods. These constructs offer the potential for patient-specific anatomical adaptation and can provide both temporary and long-term structural support for regenerating tissues. One of the most promising approaches in post-mastectomy breast reconstruction involves the use of autologous cellular and tissue components integrated into either synthetic scaffolds—such as polylactic acid (PLA), polyglycolic acid (PGA), poly(lactic-co-glycolic acid) (PLGA), and polycaprolactone (PCL)—or naturally derived biopolymer-based matrices, including alginate, chitosan, hyaluronic acid derivatives, collagen, fibrin, gelatin, and silk fibroin. In this context, two complementary research directions are gaining increasing significance: (1) the development of novel hybrid biomaterials that combine the favorable characteristics of both synthetic and natural polymers while maintaining biocompatibility and biodegradability; and (2) the advancement of three-dimensional bioprinting technologies for the fabrication of patient-specific scaffolds capable of incorporating cellular therapies. Such therapies typically involve mesenchymal stromal cells (MSCs) and bioactive signaling molecules, such as growth factors, aimed at promoting angiogenesis, cellular proliferation, and lineage-specific differentiation. In our review, we analyze existing developments in this area and discuss the advantages and disadvantages of 3D disassemblable scaffolds for mammary gland reconstruction, as well as prospects for their further research and clinical use. Full article

The c-ErbB receptor family is a fundamental cell signaling system that regulates cell proliferation, motility, apoptosis, differentiation, and other key cellular functions. Overexpressed and mutated in some tumors, c-ErbB receptors play a pivotal role in their progression but are also present in many non-malignant cells, including those that are promising from the point of view of regenerative medicine, such as mesenchymal stromal cells (MSCs). The role of c-ErbB receptors in these cells is not clearly understood, and the data on their expression are sporadic. Therefore, the systemic characterization of c-ErbB receptor family expression in MSCs from a wide range of tissues is of high priority. Here, using RT-qPCR and Western blotting analysis, we evaluated the c-ErbB receptors expression pattern at the mRNA and protein levels in human MSCs isolated from six different tissues. We found that MSCs possess considerable EGFR and HER2 mRNA levels comparable to those in some malignant cells while showing trace HER3 and HER4 expression. However, EGFR but not HER2 was detected in MSCs at the protein level. We also show that the absence of HER2 protein is not associated with its rapid lysosomal degradation. We conclude that c-ErbB signaling in human MSCs is exclusively mediated by EGFR. 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

Photobiomodulation (PBM) utilizes different wavelengths of light to modulate cellular functions and has emerged as a promising approach in regenerative medicine. In this study, we examined the effects of blue (455 nm), red (660 nm), and near-infrared (810 nm) light, both individually and in combination, on human adipose-derived mesenchymal stem/stromal cells (adMSCs). A single, short-term exposure of adMSCs in suspension to these wavelengths using an integrating sphere revealed distinct wavelength- and dose-dependent cellular responses. Blue light exposure led to a dose-dependent increase in intracellular reactive oxygen species, accompanied by reduced cell proliferation, metabolic activity, interleukin-6/interleukin-8 secretion, and adipogenic differentiation. In contrast, red and near-infrared light preserved cell viability and metabolic function while enhancing cell migration, consistent with their documented ability to stimulate proliferation and mitochondrial activity in mesenchymal stem cells. These findings highlight the necessity of precise wavelength and dosage selection in PBM applications and support the potential of PBM as a customizable tool for optimizing patient-specific regenerative therapies. Full article

Objectives: COVID-19, caused by the SARS-CoV-2 virus, has infected over 777 million individuals and led to approximately 7 million deaths worldwide. Despite significant efforts to develop effective therapies, treatment remains largely supportive, especially for severe complications like acute respiratory distress syndrome (ARDS). Numerous compounds from diverse pharmacological classes are currently undergoing preclinical and clinical evaluation, targeting both the virus and the host immune response. Methods: Despite the large number of articles published and after a preliminary attempt was published, we discarded the option of a systematic review. Instead, we have done a description of therapies with these results and a tentative mechanism of action. Results: Preliminary studies and early-phase clinical trials have demonstrated the potential of Mesenchymal Stem Cells (MSCs) in mitigating severe lung damage in COVID-19 patients. Previous research has shown MSCs to be effective in treating various pulmonary conditions, including acute lung injury, idiopathic pulmonary fibrosis, ARDS, asthma, chronic obstructive pulmonary disease, and lung cancer. Their ability to reduce inflammation and promote tissue repair supports their potential role in managing COVID-19-related complications. This review demonstrates the utility of MSCs in the acute phase of COVID-19 and postulates the etiopathogenic role of mitochondria in Long-COVID. Even more, their combination with other therapies is also analyzed. Conclusions: While the therapeutic application of MSCs in COVID-19 is still in early stages, emerging evidence suggests promising outcomes. As research advances, MSCs may become an integral part of treatment strategies for severe COVID-19, particularly in addressing immune-related lung injury and promoting recovery. However, a full pathogenic mechanism may explain or unify the complexity of signs and symptoms of Long COVID and Post-Acute Sequelae (PASC). Full article

We present a narrative review focusing on the therapeutic potential of mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) in regenerating bone defects, particularly those resulting from surgical treatment of malignant bone and soft tissue tumors. These large bone defects pose significant challenges for reconstruction and functional recovery, highlighting the need for innovative regenerative strategies. Background: MSCs, which can differentiate into various cell types, are known for their immunosuppressive properties and ability to promote tissue repair. MSC-EVs, rich in bioactive molecules like microRNAs and proteins, play a crucial role in bone regeneration by mediating intercellular communication and modulating inflammation. Methods: This narrative review compiles data from various studies, including systematic reviews and individual research, focusing on the application of MSC-EVs in bone defect treatment. It examines the characteristics, mechanisms of action, and therapeutic effects of MSC-EVs, as well as the microRNAs involved in bone regeneration. Results: The findings indicate that MSC-EVs can enhance both osteogenesis and angiogenesis, highlighting their potential as promising candidates for clinical applications in bone defects. However, many mechanisms remain unclear; therefore, further investigation is needed. Conclusions: The review emphasizes the potential of MSC-EVs in improving patient outcomes for severe bone defects. It also highlights future challenges, including formulation, standardization, safety, and delivery methods, particularly in conjunction with biomaterials. Overall, MSC-EVs represent a significant advancement in regenerative medicine for bone defects. Full article

Mesenchymal stromal cells (MSCs) have demonstrated therapeutic efficacy across numerous clinical applications, with evidence suggesting their paracrine effects, particularly through extracellular vesicles (EVs), possibly driving functional outcomes. In this study we perform the comprehensive characterization of microRNA expression profiles in human MSC-derived EVs (MSC-EV) compared to their parental cells, cultured under clinically relevant xeno-free conditions. MSCs were isolated from the bone marrows of healthy donors and characterised according to the International Society for Cellular Therapy criteria, while MSC-EVs were isolated using differential ultracentrifugation and validated according to the International Society for Extracellular Vesicle guidelines. NanoString profiling identified 590 mature microRNAs expressed across both populations, with 42 being significantly differentially expressed between MSC-EVs and parental MSCs. Five microRNAs were distinctly highly expressed in MSCs and five in MSC-EVs, while fifteen of the top twenty most abundant microRNAs showed high expression in both populations. MicroRNA expression patterns were validated in an independent cohort. Functional pathway analysis of differentially expressed microRNAs showed enrichment of key biological processes including cell proliferation, differentiation, and immune regulation. This standardised profiling approach develops our understanding of MSC/MSC-EV microRNA cargo, using a transparent methodological approach that allows for the improved comparability of datasets for the development and advancement of MSC-EV therapeutics. Full article

Beyond its immunological role, colostrum has emerged as a promising, non-invasive source of bioactive factors, including mesenchymal stem/stromal cells (MSCs). This study represents the first attempt to isolate and characterize MSCs from equine colostrum (C-MSCs) to assess their potential use in veterinary regenerative medicine. Colostrum (n = 6) was collected from mares immediately after their delivery and centrifuged, and the recovered cells were cultured under standard conditions. The C-MSCs displayed plastic adherence and a heterogeneous morphology, including spindle-shaped and epithelial-like cells. The population doubling time (PDT) values varied among the samples, and four out of six showed rapid proliferation (<2 days). Colony-forming unit (CFU) assays confirmed their clonogenic potential, though significant inter-sample variability was observed (p < 0.05). Spheroid formation assays revealed differences in cell–cell adhesion: four out of six samples formed stable spheroids within four days. A migration assay showed significant variability (p < 0.05): one out of six achieved complete wound closure within 72 h, whereas five out of six reached ~30% at 96 h. All samples were positive for adipogenic, chondrogenic, and osteogenic differentiation as shown via staining. RT-PCR confirmed MSC marker expression, while hematopoietic markers were absent. MHC-I expression was weak in five out of six samples, whereas MHC-II was consistently negative. These findings support equine colostrum as a viable MSC source, though its variability requires further validation with larger samples. Additional research is needed to investigate C-MSCs’ immunomodulatory properties and therapeutic potential. Full article

Nerve tissue damage is an unsolved problem in modern neurology and neurosurgery, which prompts the need to search for approaches to stimulate neuroprotection and regeneration of neural tissue. Earlier we have shown that the secretome of human mesenchymal stromal cells (MSCs) stimulates rat survival, reduces the severity of neurological deficits, and decreases the volume of brain damage in a hemorrhagic stroke model. A significant disadvantage of using the MSC secretome is the need to concentrate it (at least 5–10 fold) to achieve appreciable pharmacological activity. This increases the cost of obtaining clinically applicable amounts of secretome and slows down the clinical translation of this technology. Here, we created a number of genetically modified human MSC cultures, including immortalized MSCs and those with hyperexpression of brain-derived neurotrophic factor (BDNF) and urokinase-type plasminogen activator (uPA) and with suppressed expression of Von Hippel–Lindau tumor suppressor (VHL), and we evaluated the pharmacological activity of their secretomes in a model of intracerebral hemorrhage (ICH) in rats. The secretome of MSCs immortalized by hyperexpression of the catalytic subunit of human telomerase (hTERT) revealed neuroprotective activity indistinguishable from that of primary MSC cultures, yet it still required 10-fold concentration to achieve neuroprotective efficacy. The secretome of MSC culture with combined hyperexpression of BDNF and uPA and suppressed expression of Von Hippel–Lindau tumor suppressor even without additional concentration reduced the severity of neurological disorders and decreased brain lesion volume in the ICH model. The secretomes of MSCs with separate overexpression of BDNF and uPA or suppression of VHL had no such effect or, on the contrary, revealed a toxic effect in the ICH model. Presumably, this may be due to an imbalance in the representation of individual growth factors in the secretome of genetically modified MSCs, which individually may lead to undesirable effects in damaged nervous tissue, such as increased permeability of the blood–brain barrier (under the influence of pro-angiogenic factors) or neural cell apoptosis (due to an excess of neurotrophic factors). The obtained data show that genetic modification of MSC cultures can enhance or alter the therapeutic activity of their secretomes, which can be used in the creation of promising sources of biopharmaceutical substances. 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

Bone repair and regeneration following an injury still present challenges worldwide. Three-dimensional (3D) scaffolds made from various materials are used for bone tissue engineering (BTE) applications. Polymers, minerals and nanotechnology are now being used in combination to achieve specific goals for BTE, including the delivery of antimicrobials through the scaffolds to prevent post-surgical infection. While several materials are utilised for BTE, natural polymers present a unique set of materials that can be manipulated to formulate scaffolds for BTE applications. They have been found to demonstrate higher biocompatibility, biodegradability and lower toxicity. Some even naturally mimic the bone microarchitecture, providing inherent structural support for BTE. Natural polymers may be simply classified as those from plant and animal sources. From both sources, there are different types of proteins, polysaccharides and other specialised materials that are already in use for research in BTE. Interestingly, these have the potential to revolutionise the field of BTE with a sustainable approach. In this review, we first discuss the different natural polymers used in BTE from plant sources, followed by animal sources. We then explore novel materials that are aimed at sustainable approaches, focusing on innovation from the last decade. In these sections, we outline studies of these materials with different types of bone cells, including bone marrow mesenchymal stromal cells (MSCs), which are the progenitors of bone. We finally outline the limitations, conclusions and future directions from our perspective in this dynamic field of polymers in BTE. With this review, we hope to bring together the updated existing knowledge and the potential future of innovation and sustainability in natural polymers for biomimetic BTE applications for fellow scientists, researchers and surgeons in the field. Full article

Mesenchymal stromal cells of the tumor microenvironment (TME) play a significant role in the progression of multiple myeloma (MM). The cells of the TME demonstrate resistance to treatment, thereby creating a favorable environment for disease relapse. The status of the TME during remission is poorly understood. An association between treatment response and TME status (including signaling pathways) has been suggested. One of the key players in the establishment of the MM TME is WNT signaling. In this study, we evaluated the expression of WNT family proteins in the TME and MM cells to assess their potential as TME markers and predictors of treatment response. A bioinformatic analysis of normal and malignant plasma cells, combined with an analysis of published data, revealed the following differentially expressed WNT genes: WNT5A, WNT10B, CTNNB1, and WNT3A. Immunohistochemical staining with the antibodies against the proteins encoded by the genes was conducted on trephine biopsy samples of bone marrow from healthy donors and patients with different responses to therapy. A quantitative analysis of the immunohistochemical data revealed differences in the amounts of WNT3A, WNT5A, WNT10B, and β-catenin proteins in the bone marrow before treatment depending on the subsequent responses of the patients to therapy. Multiplex fluorescent immunohistochemical staining with tyramide signal amplification revealed that WNT3A was predominantly present in mesenchymal stromal cells, whereas WNT5A and WNT10B were primarily observed in plasma cells. β-catenin was detected in both cell types. We analyzed the mRNA levels of the WNT gene family and CTNNB1 in MSC cultures from healthy donors and patients using qPCR. These genes were differentially expressed in MSC cultures derived from patients and healthy donors, as well as between patients grouped according to their response to therapy. Therefore, WNT proteins and β-catenin can be considered potential markers to assess the state of the tumor niche. Full article

Isoforms of prostate transmembrane protein, androgen induced 1 (PMEPA1), are regulated either by TGF-beta or AR activation and provide negative loop-regulation of these signaling pathways. High levels of PMEPA1 protein have been observed in various tumor types, including prostate, bladder, colorectal cancers, and glioblastoma. Direct oncogenic role of PMEPA1 in hepatocellular carcinoma has been recently shown on an animal model. New studies also indicate an upregulation of PMEPA1 in tumor-associated immune and stromal cells; however, its specific role in tumor stromal cells remains largely unexplored. In our previous research, we developed a cancer-stroma sphere (CSS) model that integrates tumor cells with mesenchymal stem cells (MSCs). Evaluations of chemotherapy and CAR-T therapies on CSSs have demonstrated that this model closely mimics in vivo data regarding cytotoxicity and adverse effects of therapy. In the present study, we reveal that PMEPA1 is significantly overexpressed in MSCs within the CSS. Moreover, this overexpression has been induced under short-term co-culture conditions. Among the five isoforms of PMEPA1, PMEPA1a and PMEPA1b isoforms have been detected in MSCs. These findings underscore the potential role of PMEPA1 in the tumor microenvironment modulation by MSCs. Full article