Molecular Mechanisms Responsible for Therapeutic Potential of Mesenchymal Stem Cell-Derived Secretome

ROS responsive conductive microspheres loaded with salvianolic acid B as adipose derived stem cell carriers for acute myocardial infarction treatment

Stem cell therapy is currently the most promising strategy for the treatment of myocardial infarction. However, the development of injectable cell carriers that can scavenge reactive oxygen species (ROS) in the infarct zone to improve transplanted cell survival remains a challenge. Here, we developed a ROS responsive conductive microsphere based on chitosan (CS) and dextran (DEX) with 4-formylphenylboronic acid (4-FPBA) as a cross-linking agent and the addition of graphite oxide (GO) and the anti-inflammatory agent salvianolic acid B (SalB), as a cell delivery carrier for myocardial infarction. These microspheres were crosslinked by dual dynamic networks of Schiff base and phenylborate bonds. The relationship between CS concentration and microsphere particle size, as well as the biocompatibility, ROS responsiveness, anti-inflammatory properties, and effects on myogenic differentiation of H9C2 cells were fully investigated. The microspheres exhibit good biocompatibility, proliferation promoting, differentiation promoting, antioxidant, and anti-inflammatory properties. When applied to mice myocardial infarction models, the ROS responsive conductive microspheres loaded with SalB and adipose derived stem cells (ADSC) exhibited excellent in vivo repair ability. In addition, they reduced myocardial fibrosis and promoted ventricular wall regeneration by promoting the expression of Connexin 43 (Cx43) and CD31, ultimately reshaping the infarcted myocardium, suggesting their great potential as cell delivery carriers for myocardial infarction treatment.

hUC-MSCs Prevent Acute High-Altitude Injury through Apoe/Pdgf-b/p-Erk1/2 Axis in Mice

BACKGROUND

The hypobaric hypoxic atmosphere can cause adverse reactions or sickness. The purpose of this study was to explore the preventive effect and mechanism of human umbilical cord mesenchymal stem cells (hUC-MSCs) on acute pathological injury in mice exposed to high-altitude.

METHODS

We pretreated C57BL/6 mice with hUC-MSCs via the tail vein injection, and then the mice were subjected to hypobaric hypoxic conditions for five days. The effects of hUC-MSCs on the pathological injury of lung, heart, brain were assessed by biochemical analysis, histopathological testing, quantitative real-time polymerase chain reaction (qPCR), and western blot (WB). Further, transcriptome sequencing was used to screen for the potential therapeutic targets of hUC-MSCs in acute pathological injury, the identified signaling axis was characterized using Apoe-/- mice, qPCR and WB.

RESULTS

hUC-MSCs administration notably prevented and relieved gastrointestinal symptoms and inflammation of lung and heart, increased blood oxygen saturation and serum superoxide dismutase (SOD) level, decreased serum malondialdehyde (MDA) level, rescued lung tissue injury and myocardial mitochondrial disorder, elevated nissl bodies number in brain tissue and reduced the degree of pulmonary and cerebral edema. Furthermore, hUC-MSCs pretreatment reversed the down-regulated Apoe and up-regulated Pdgf-b and p-Erk1/2 in the lung of hypobaric hypoxic mice. Thus, hUC-MSCs protected against acute pathological injury caused by hypobaric hypoxic condition via the Apoe/Pdgf-b/p-Erk1/2 axis, and the identified pathway was confirmed by the negative results of Apoe-/- mice.

CONCLUSION

hUC-MSCs possess the preventive effect on acute pathological injury caused by hypobaric hypoxia environment at high-altitude.

Protective Effect of Conditioned Medium of Immortalized Human Stem Cells from Exfoliated Deciduous Teeth Against Hair Graying Caused by X-Ray Irradiation via Its Antioxidative Activity

Hair graying is one of the common visible signs of human aging, resulting from decreased or abolished melanogenesis due to the depletion of melanocyte stem cells through excess accumulation of oxidative stress. Cell-free therapy using a conditioned medium (CM) of mesenchymal stem cells has been highlighted in the field of regenerative medicine owing to its potent therapeutic effects with lower regulatory hurdles and safety risk. Recently, we demonstrated that a CM of an immortalized stem cell line from human exfoliated deciduous teeth (SHED) has protective effects against a mouse model of ulcer formation via antioxidative and angiogenic activities mediated by HGF and VEGF. However, to date, no effective treatments for hair graying have been developed, and the effect of SHED-CM on hair graying remains unknown. In this study, we have investigated the effect of SHED-CM on a hair graying mouse model caused by X-ray irradiation. Repetitive subcutaneous administrations of SHED-CM greatly suppressed the development of hair graying, when compared to control medium, resulting in reduced cutaneous expression of 8-hydroxy-2'-deoxyguanosine, the major product of DNA damage induced by reactive oxygen species. Consistent with these in vivo results, SHED-CM significantly inhibited the cell death caused by X-ray irradiation in melanoma cell line B16F10 cells. Immunodepletion of HGF or VEGF in the SHED-CM revealed that this inhibition was due to suppression of the generation of reactive oxygen species, which was mainly mediated by HGF and probably VEGF. These results suggest that SHED-CM has protective effects against hair graying via its antioxidative activity.

RNA sequencing reveals key factors modulating TNFα-stimulated odontoblast-like differentiation of dental pulp stem cells

Inflammation is a complex host response to harmful infections or injuries, playing both beneficial and detrimental roles in tissue regeneration. Notably, clinical dentinogenesis associated with caries development occurs within an inflammatory environment. Reparative dentinogenesis is closely linked to intense inflammation, which triggers the recruitment and differentiation of dental pulp stem cells (DPSCs) into the dentin lineage. Understanding how inflammatory responses influence DPSCs is essential for elucidating the mechanisms underlying dentin and pulp regeneration. Given the limited data on this process, a broad approach is employed here to gain a deeper understanding of the complex mechanisms involved and to identify downstream signaling targets. This study aims to investigate the role of inflammation and the complement receptor C5L2 in the odontoblastic differentiation of DPSCs and the associated transcriptomic changes using poly-A RNA sequencing (RNA-seq). RNA-seq techniques provide insight into the transcriptome of a cell, offering higher coverage and greater resolution of its dynamic nature. Following inflammatory stimulation, DPSCs exhibit significantly altered gene profiles, including marked upregulation of key odontogenic genes, highlighting the critical role of inflammation in dentinogenesis. We demonstrate that TNFα-treated odontoblast-like differentiating DPSCs, under C5L2 modulation, exhibit significant differential gene expression and transcriptomic changes. The data presented may provide new avenues for experimental approaches to uncover pathways in dentinogenesis by identifying specific transcription factors and gene profiles.

miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow-derived neural crest cells

JOURNAL/nrgr/04.03/01300535-202501000-00035/figure1/v/2024-05-14T021156Z/r/image-tiff Our previous study found that rat bone marrow-derived neural crest cells (acting as Schwann cell progenitors) have the potential to promote long-distance nerve repair. Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication. Nevertheless, the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear. To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves, we collected conditioned culture medium from hypoxia-pretreated neural crest cells, and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation. The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells. We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells. Subsequently, to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons, we used a microfluidic axonal dissociation model of sensory neurons in vitro, and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons, which was greatly dependent on loaded miR-21-5p. Finally, we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb, as well as muscle tissue morphology of the hind limbs, were obviously restored. These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p. miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome. This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves, and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.

The paradigm of stem cell secretome in tissue repair and regeneration: Present and future perspectives

As the number of patients requiring organ transplants continues to rise exponentially, there is a dire need for therapeutics, with repair and regenerative properties, to assist in alleviating this medical crisis. Over the past decade, there has been a shift from conventional stem cell treatments towards the use of the secretome, the protein and factor secretions from cells. These components may possess novel druggable targets and hold the key to profoundly altering the field of regenerative medicine. Despite the progress in this field, clinical translation of secretome-containing products is limited by several challenges including but not limited to ensuring batch-to-batch consistency, the prevention of further heterogeneity, production of sufficient secretome quantities, product registration, good manufacturing practice protocols and the pharmacokinetic/pharmacodynamic profiles of all the components. Despite this, the secretome may hold the key to unlocking the regenerative blockage scientists have encountered for years. This review critically analyses the secretome derived from different cell sources and used in several tissues for tissue regeneration. Furthermore, it provides an overview of the current delivery strategies and the future perspectives for the secretome as a potential therapeutic. The success and possible shortcomings of the secretome are evaluated.

Standardization to Characterize the Complexity of Vessel Network Using the Aortic Ring Model

Regeneration after ischemia requires to be promoted by (re)perfusion of the affected tissue, and, to date, there is no therapy that covers all needs. In treatment with mesenchymal stem cells (MSC), the secretome acts via paracrine mechanisms and has a positive influence on vascular regeneration via proangiogenic factors. A lack of standardization and the high complexity of vascular structures make it difficult to compare angiogenic readouts from different studies. This emphasizes the need for improved approaches and the introduction of an index in the preclinical setting. A characterization of human MSC secretomes obtained from one of the three formats-single cells, small, and large spheroids-was performed using the chicken aortic ring assay in combination with a modified angiogenic activity index (AAI) and an angiogenic profile. While the secretome of the small spheroid group showed an inhibitory effect on angiogenesis, the large spheroid group impressed with a fully pro-angiogenic response, and a higher AAI compared to the single cell group, underlying the suitability of these three-stem cell-derived secretomes with their distinct angiogenic properties to validate the AAI and the novel angiogenic profile established here.

Repair effect analysis of mesenchymal stem cell conditioned media from multiple sources on HUVECs damaged by high glucose

BACKGROUND

The therapeutic potential of mesenchymal stem cells (MSCs) may be partly attributed to their secretion growth factors, cytokines and chemokines. In various preclinical studies, the use of MSC-conditioned media (CM) has demonstrated promising potential for promoting vascular repair.

METHODS

To gain a comprehensive understanding of the variations in conditioned media derived from different sources of mesenchymal stem cells (MSCs) including umbilical cord, adipose and bone marrow, we investigated their reparative effects on human umbilical vein endothelial cells (HUVECs) subjected to damage induced by high glucose. Initially, the secreted proteins from the three types of MSCs were assessed using the bicinchoninic acid (BCA) method. Subsequently, we examined the influence of different type of MSC secreted proteins on the proliferation of HUVECs under high glucose conditions. Following this, transwell migration experiments were conducted to evaluate the impact of MSC source on the migration of HUVECs damaged by high glucose. We further compared the effects of adding secreted proteins from the three types of MSCs on the tube formation ability of HUVECs subjected to high glucose damage. Finally, tandem mass tag (TMT) labeling quantitative proteomics was performed to analyze differently expressed proteins in the secreted proteins of three type MSC by using LC-MS/MS.

RESULTS

In this study, we observed a significantly higher secretion of proteins from umbilical cord mesenchymal stem cells (UMSCs) compared to adipose-derived stem cells (ADSCs). Subsequently, we found that the of proliferation HUVECs was significantly improved with supplementing the three MSCs secreted proteins under high glucose medium. Notably, the reparative effects of bone marrow mesenchymal stem cells (BMSCs) and UMSCs were superior to those of ADSCs. Afterwards, UMSCs exhibited the strongest ability to repair cell migration when HUVECs damaged by high glucose. Moreover, all three MSCs' secreted proteins exhibited the ability to enhance tube formation. Importantly, the UMSCs' secretome showed the most pronounced improvement in tube formation, as evidenced by the evaluation of parameters such as the number of nodes, the number of branches, and total length. These findings suggest that the UMSCs' secretome plays a crucial role in biological processes such as vasculature development, cell adhesion, and tissue remodeling. Additionally, the BMSCs' secretome was found to promote vascular development. The results collectively indicate the diverse therapeutic potential of MSC secretomes in influencing various aspects of cellular function and tissue repair.

CONCLUSION

In conclusion, this study offers a valuable reference for the selection of more suitable sources of mesenchymal stem cells (MSCs) in the treatment of diabetic cardiovascular disease.

Metabolic Mode of Alginate-Encapsulated Human Mesenchymal Stromal Cells as a Background for Storage at Ambient Temperature

Introduction: Human mesenchymal stromal cells (MSCs) are attractive for both medical practice and biomedical research. Nonfreezing short-term storage may provide safe and simple transportation and promote the practical use of MSCs. Objectives: We aimed to determine the duration of efficient storage at ambient temperature (22°C) of human dermal MSCs in different three-dimensional organization and to investigate the role of cell metabolic mode in the resistance to the ambient storage damaging factors. Methods: MSCs in monolayer, suspension, and encapsulated in alginate microspheres (AMS) were stored in sealed containers at 22°С in culture medium. Viability (fluorescein diacetate /ethidium bromide) and metabolic activity (Alamar Blue assay) were assessed at 0, 3, 7, 10, and 14 days of the storage. Mitochondrial membrane potential (JC-1 test), cell cycle analysis, reactive oxygen species level, and resistance to hydrogen peroxide were analyzed under culture conditions. Results: Alginate encapsulation was shown to maintain viability (about 85%), metabolic activity, and adhesion ability during storage for 7 days. The storage of MSCs in both monolayer and suspension was less efficient. Culture of MSCs in AMS decreased basal metabolic activity, mitochondrial activity, and led to reversible cell cycle arrest compared to standard two-dimensional culture. MSCs in AMS have a lower basal level of reactive oxygen species and higher resistance to hydrogen peroxide compared with those in monolayer culture. Conclusion: Revealed shift into quiescent metabolic mode is essential for alginate-encapsulated MSCs resistance to storage at ambient temperature.

Targeted Therapy for Severe Sjogren's Syndrome: A Focus on Mesenchymal Stem Cells

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by the infiltration of lymphocytes on salivary and lacrimal glands, resulting in their dysfunction. Patients suffering from severe pSS have an increased risk of developing multi-organ dysfunction syndrome due to the development of systemic inflammatory response, which results in immune cell-driven injury of the lungs, kidneys, liver, and brain. Therapeutic agents that are used for the treatment of severe pSS encounter various limitations and challenges that can impact their effectiveness. Accordingly, there is a need for targeted, personalized therapy that could address the underlying detrimental immune response while minimizing side effects. Results obtained in a large number of recently published studies have demonstrated the therapeutic efficacy of mesenchymal stem cells (MSCs) in the treatment of severe pSS. MSCs, in a juxtacrine and paracrine manner, suppressed the generation of inflammatory Th1 and Th17 lymphocytes, induced the expansion of immunosuppressive cells, impaired the cross-talk between auto-reactive T and B cells, and prevented the synthesis and secretion of auto-antibodies. Additionally, MSC-derived growth and trophic factors promoted survival and prevented apoptosis of injured cells in inflamed lacrimal and salivary glands, thereby enhancing their repair and regeneration. In this review article, we summarized current knowledge about the molecular mechanisms that are responsible for the beneficial effects of MSCs in the suppression of immune cell-driven injury of exocrine glands and vital organs, paving the way for a better understanding of their therapeutic potential in the targeted therapy of severe pSS.

Immortalization of Mesenchymal Stem Cells for Application in Regenerative Medicine and Their Potential Risks of Tumorigenesis

Regenerative medicine utilizes stem cells to repair damaged tissues by replacing them with their differentiated cells and activating the body's inherent regenerative abilities. Mesenchymal stem cells (MSCs) are adult stem cells that possess tissue repair and regenerative capabilities and immunomodulatory properties with a much lower risk of tumorigenicity, making them a focus of numerous clinical trials worldwide. MSCs primarily exert their therapeutic effects through paracrine effects via secreted factors, such as cytokines and exosomes. This has led to increasing interest in cell-free therapy, where only the conditioned medium (also called secretome) from MSC cultures is used for regenerative applications. However, MSCs face certain limitations, including cellular senescence, scarcity, donor heterogeneity, complexity, short survival post-implantation, and regulatory and ethics hurdles. To address these challenges, various types of immortalized MSCs (ImMSCs) capable of indefinite expansion have been developed. These cells offer significant promise and essential tools as a reliable source for both cell-based and cell-free therapies with the aim of translating them into practical medicine. However, the process of immortalization, often involving the transduction of immortalizing genes, poses potential risks of genetic instability and resultant malignant transformation. Cell-free therapy is particularly attractive, as it circumvents the risks of tumorigenicity and ethical concerns associated with live cell therapies. Rigorous safety tests, such as monitoring chromosomal abnormalities, are critical to ensure safety. Technologies like inducible or suicide genes may allow for the controlled proliferation of MSCs and induce apoptosis after their therapeutic task is completed. This review highlights recent advancements in the immortalization of MSCs and the associated risks of tumorigenesis.

The Potential of Mesenchymal Stem Cell-Derived Exosomes in Cardiac Repair

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, and effectively repairing the heart following myocardial injuries remains a significant challenge. Research has increasingly shown that exosomes derived from mesenchymal stem cells (MSC-Exo) can ameliorate myocardial injuries and improve outcomes after such injuries. The therapeutic benefits of MSC-Exo are largely due to their capacity to deliver specific cargo, including microRNAs and proteins. MSC-Exo can modulate various signaling pathways and provide several beneficial effects, including cytoprotection, inflammation modulation, and angiogenesis promotion to help repair the damaged myocardium. In this review, we summarize the cardioprotective effects of MSC-Exo in myocardial injury, the underlying molecular mechanism involved in the process, and various approaches studied to enhance their efficacy based on recent findings.

Unlocking the Therapeutic Potential of Adipose-Derived Stem Cell Secretome in Oral and Maxillofacial Medicine: A Composition-Based Perspective

The adipose-derived stem cell (ADSC) secretome is widely studied for its immunomodulatory and regenerative properties, yet its potential in maxillofacial medicine remains largely underexplored. This review takes a composition-driven approach, beginning with a list of chemokines, cytokines, receptors, and inflammatory and growth factors quantified in the ADSC secretome to infer its potential applications in this medical field. First, a review of the literature confirmed the presence of 107 bioactive factors in the secretome of ADSCs or other types of mesenchymal stem cells. This list was then analyzed using the Search Tool for Retrieval of Interacting Genes/Proteins (STRING) software, revealing 844 enriched biological processes. From these, key processes were categorized into three major clinical application areas: immunoregulation (73 factors), bone regeneration (13 factors), and wound healing and soft tissue regeneration (27 factors), with several factors relevant to more than one area. The most relevant molecules were discussed in the context of existing literature to explore their therapeutic potential based on available evidence. Among these, TGFB1, IL10, and CSF2 have been shown to modulate immune and inflammatory responses, while OPG, IL6, HGF, and TIMP1 contribute to bone regeneration and tissue repair. Although the ADSC secretome holds great promise in oral and maxillofacial medicine, further research is needed to optimize its application and validate its clinical efficacy.

Cell therapy for end-stage liver disease: Current state and clinical challenge

ABSTRACT

Liver disease involves a complex interplay of pathological processes, including inflammation, hepatocyte necrosis, and fibrosis. End-stage liver disease (ESLD), such as liver failure and decompensated cirrhosis, has a high mortality rate, and liver transplantation is the only effective treatment. However, to overcome problems such as the shortage of donor livers and complications related to immunosuppression, there is an urgent need for new treatment strategies that need to be developed for patients with ESLD. For instance, hepatocytes derived from donor livers or stem cells can be engrafted and multiplied in the liver, substituting the host hepatocytes and rebuilding the liver parenchyma. Stem cell therapy, especially mesenchymal stem cell therapy, has been widely proved to restore liver function and alleviate liver injury in patients with severe liver disease, which has contributed to the clinical application of cell therapy. In this review, we discussed the types of cells used to treat ESLD and their therapeutic mechanisms. We also summarized the progress of clinical trials around the world and provided a perspective on cell therapy.

BMSC Derived Exosomes Attenuate Apoptosis of Temporomandibular Joint Disc Chondrocytes in TMJOA via PI3K/AKT Pathway

Bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exos) are crucial means of intercellular communication and can regulate a range of biological processes by reducing inflammation, decreasing apoptosis and promoting tissue repair. We treated temporomandibular joint (TMJ) disc chondrocytes with TNF-α and performed local injection of sodium iodoacetate (MIA) in the TMJ of rats to establish in vitro and in vivo models of TMJ osteoarthritis (TMJOA). BMSC-Exos were isolated and extracted to evaluate their proliferation and trilineage differentiation abilities, and their antiapoptotic and chondroprotective effects were assessed. This study revealed that BMSC-Exos can be endocytosed by TMJ disc chondrocytes in vitro and that BMSC-Exos pretreatment strongly attenuated the inhibitory effect of TNF-α on the proliferative and chondrogenic potential of TMJ disc chondrocytes. The administration of BMSC-Exos significantly suppressed TNF-α-induced apoptosis in TMJ disc chondrocytes by increasing the phosphorylation level of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) pathway-related proteins, whereas the PI3K inhibitor LY294002 neutralized this antiapoptotic effect. Intradiscal injection of BMSC-Exos alleviated the degeneration and inflammation of TMJ discs in a rat model of TMJOA. Our study revealed that BMSC-Exos can attenuate the apoptosis of TMJ disc chondrocytes and destruction of TMJ discs partially by inhibiting the apoptotic pathway and activating the PI3K/AKT pathway, thereby providing a promising treatment strategy for the regeneration of damaged TMJ discs.

Initial WNT/β-Catenin or BMP Activation Modulates Inflammatory Response of Mesodermal Progenitors Derived from Human Induced Pluripotent Stem Cells

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.

Therapeutic Effects of Exosomal miRNA-4731-5p from Adipose Tissue-Derived Stem Cells on Human Glioblastoma Cells

BACKGROUND AND AIM

Several microRNAs (miRNAs) are differentially expressed and serve as tumor suppressors in glioblastoma (GBM). The present study aimed to elucidate the function of exosomal microRNA-4731-5p (miR-4731-5p) from adipose tissue-derived mesenchymal stem cells (AD-MSCs) in the activity of human GBM cell lines.

METHOD

First, GBM-related miRNAs, their expression, and potential target genes and cytokines of miR-4731-5p were identified using bioinformatic datasets. Subsequently, purified AD-MSCs were transfected with a miRNA-4731-5p expression plasmid, and exosomes were isolated and characterized. Next, the transfection process was confirmed and the 50% inhibitory concentration (IC50) of the overexpressed exosomal miRNA-4731-5p was inhibited for cancer cells. The probable anticancer action of exosomal miRNA-4731-5p on U-87 and U-251 GBM cell lines was verified by flow cytometry, DAPI staining, cell cycle, real-time PCR, and wound healing assays.

RESULTS

A concentration of 50 ng/mL of miRNA-4731-5p-transfected exosomes was the safe dose for anticancer settings. The results showed that the exosomal miR-4731-5p exerted an inhibitory effect on the cell cycle and migration and induced apoptosis in GBM cell lines by regulating the phosphoinositide-3-kinase-AKT (PI3K-AKT) and nuclear factor-kB (NF-kB) signaling pathways.

CONCLUSION

This study reveals that the expression of exosomal miRNA-4731-5p has favorable antitumor properties for the treatment of GBM cell lines and may be a fundamental therapeutic option for this type of brain tumor.

Augmenting osteoporotic bone regeneration through a hydrogel-based rejuvenating microenvironment

Osteoporotic bone defects pose a significant challenge for bone regeneration as they exhibit impaired healing capacity and delayed healing period. To address this issue, this study introduces a hydrogel that creates a rejuvenating microenvironment, thereby facilitating efficient bone repair during the initial two weeks following bone defect surgery. The hydrogel, named GelHFS, was created through host-guest polymerization of gelatin and acrylated β-cyclodextrin. Incorporation of the human fetal mesenchymal stem cell secretome (HFS) formed GelHFS hydrogel aimed at mimicking a rejuvenated stem cell niche. Our results demonstrated that GelHFS hydrogel promotes cell stellate spreading and osteogenic differentiation via integrin β1-induced focal adhesion pathway. Implantation of GelHFS hydrogel in an osteoporotic bone defect rat model recruited endogenous integrin β1-expressing cells and enhanced new bone formation and bone strength. Our findings reveal that GelHFS hydrogel provides a rejuvenating niche for endogenous MSCs and enhances bone regeneration in osteoporotic bone defect. These findings highlight the potential of GelHFS hydrogel as an effective therapeutic strategy for addressing challenging bone healing such as osteoporotic bone regeneration.

Role of Hypoxic Secretome from Mesenchymal Stem Cells in Enhancing Tissue Repair: Regulatory Effects on HIF-1α, VEGF, and Fibroblast in a Sphincterotomy Rat Model

Background

Fecal incontinence (FI) is the inability to control bowel movements, resulting in fecal leakage. If left untreated, FI can seriously impact the long-term well-being of individuals affected. Recently, using secretome has become a promising new treatment method. The secretome combines growth factors released outside cells during stem cell development, such as mesenchymal stem cells. It consists of soluble proteins, nucleic acids, fats, and extracellular vesicles, which contribute to different cell processes. The primary aim is to assess the impact of hypoxic secretome administration on accelerating wound healing through the HIF-1α pathway in a post-sphincterotomy rat model.

Methods

The study was conducted with two distinct groups of 10 rats each, the control and treatment groups, which were injected with hypoxic secretome at 0.3 mL. The inclusion criteria for the rats were as follows: male gender, belonging to the Sprague-Dawley strain, aged between 12 to 16 weeks, with an average body weight ranging from 240 to 250 grams.

Results

There was an increase in HIF-1α gene expression in both groups. The treatment group 37 was significantly higher on day 42 (p = 0.001). VEGF increased significantly in the treatment 38 group on day 42 (p = 0.015). The neovascularization score increased significantly in the treatment 39 group during the first 24 hours (p = 0.004). The fibroblast score increased significantly in the 40 treatment group in the first 24 hours (p = 0.000) and 42 days (p = 0.035). After being given secretome, there was a higher increase in % collagen area and collagen area (µm2) in the treatment group compared to the control group (27,77 vs 11.01) and (419.027,66 vs 186.694,16).

Conclusion

The use of hypoxic secretome has a significant effect as a choice for the treatment of anal sphincter injury after sphincterotomy through the HIF-1α-VEGF-Fibroblast pathway.

Human Umbilical Cord-Mesenchymal Stem Cells Promote Extracellular Matrix Remodeling in Microglia

Human mesenchymal stem cells modulate the immune response and are good candidates for cell therapy in neuroinflammatory brain disorders affecting both adult and premature infants. Recent evidence indicates that through their secretome, mesenchymal stem cells direct microglia, brain-resident immune cells, toward pro-regenerative functions, but the mechanisms underlying microglial phenotypic transition are still under investigation. Using an in vitro coculture approach combined with transcriptomic analysis, we identified the extracellular matrix as the most relevant pathway altered by the human mesenchymal stem cell secretome in the response of microglia to inflammatory cytokines. We confirmed extracellular matrix remodeling in microglia exposed to the mesenchymal stem cell secretome via immunofluorescence analysis of the matrix component fibronectin and the extracellular crosslinking enzyme transglutaminase-2. Furthermore, an analysis of hallmark microglial functions revealed that changes in the extracellular matrix enhance ruffle formation by microglia and cell motility. These findings point to extracellular matrix changes, associated plasma membrane remodeling, and enhanced microglial migration as novel mechanisms by which mesenchymal stem cells contribute to the pro-regenerative microglial transition.

Present and future use of exosomes containing proteins and RNAs in neurodegenerative diseases for synaptic function regulation: A comprehensive review

Neurodegenerative diseases (NDDs) are increasingly prevalent with global aging, demanding effective treatments. Exosomes, which contain biological macromolecules such as RNA (including miRNAs) and proteins like α-synuclein, tau, and amyloid-beta, are gaining attention as innovative therapeutics. This comprehensive review systematically explores the potential roles of exosomes in NDDs, with a particular focus on their role in synaptic dysfunction. We present the synaptic pathophysiology of NDDs and discuss the mechanisms of exosome formation, secretion, and action. Subsequently, we review the roles of exosomes in different types of NDDs, such as Alzheimer's disease and Parkinson's disease, with a special focus on their regulation of synaptic function. In addition, we explore the potential use of exosomes as biomarkers, as well as the challenges and opportunities in their clinical application. We provide perspectives on future research directions and development trends to provide a more comprehensive understanding of and guidance for the application of exosomes in the treatment of NDDs. In conclusion, exosomes rich in biological macromolecules, as a novel therapeutic strategy, have opened up new possibilities for the treatment of NDDs and brought new hope to patients.

Application of Mesenchymal Stem Cells in Female Infertility Treatment: Protocols and Preliminary Results

Infertility is a global phenomenon that impacts people of both the male and the female sex; it is related to multiple factors affecting an individual's overall systemic health. Recently, investigators have been using mesenchymal stem cell (MSC) therapy for female-fertility-related disorders such as polycystic ovarian syndrome (PCOS), premature ovarian failure (POF), endometriosis, preeclampsia, and Asherman syndrome (AS). Studies have shown promising results, indicating that MSCs can enhance ovarian function and restore fertility for affected individuals. Due to their regenerative effects and their participation in several paracrine pathways, MSCs can improve the fertility outcome. However, their beneficial effects are dependent on the methodologies and materials used from isolation to reimplantation. In this review, we provide an overview of the protocols and methods used in applications of MSCs. Moreover, we summarize the findings of published preclinical studies on infertility treatments and discuss the multiple properties of these studies, depending on the isolation source of the MSCs used.

Enhancing Cartilage Repair: Surgical Approaches, Orthobiologics, and the Promise of Exosomes

Treating cartilage damage is challenging as its ability for self-regeneration is limited. Left untreated, it can progress to osteoarthritis (OA), a joint disorder characterized by the deterioration of articular cartilage and other joint tissues. Surgical options, such as microfracture and cell/tissue transplantation, have shown promise as techniques to harness the body's endogenous regenerative capabilities to promote cartilage repair. Nonetheless, these techniques have been scrutinized due to reported inconsistencies in long-term outcomes and the tendency for the defects to regenerate as fibrocartilage instead of the smooth hyaline cartilage native to joint surfaces. Orthobiologics are medical therapies that utilize biologically derived substances to augment musculoskeletal healing. These treatments are rising in popularity because of their potential to enhance surgical standards of care. More recent developments in orthobiologics have focused on the role of exosomes in articular cartilage repair. Exosomes are nano-sized extracellular vesicles containing cargo such as proteins, lipids, and nucleic acids, and are known to facilitate intercellular communication, though their regenerative potential still needs to be fully understood. This review aims to demonstrate the advancements in cartilage regeneration, highlight surgical and biological treatment options, and discuss the recent strides in understanding the precise mechanisms of action involved.

Autologous hGMSC-Derived iPS: A New Proposal for Tissue Regeneration

The high mortality in the global population due to chronic diseases highlights the urgency to identify effective alternative therapies. Regenerative medicine provides promising new approaches for this purpose, particularly in the use of induced pluripotent stem cells (iPSCs). The aim of the work is to establish a new pluripotency cell line obtained for the first time by reprogramming human gingival mesenchymal stem cells (hGMSCs) by a non-integrating method. The hGMSC-derived iPS line characterization is performed through morphological analysis with optical and electron scanning microscopy and through the pluripotency markers expression evaluation in cytofluorimetry, immunofluorescence, and RT-PCR. To confirm the pluripotency of new hGMSC-derived iPS, the formation of embryoid bodies (EBs), as an alternative to the teratoma formation test, is studied in morphological analysis and through three germ layers' markers' expression in immunofluorescence and RT-PCR. At the end, a comparative study between parental hGMSCs and derived iPS cells is performed also for the extracellular vesicles (EVs) and their miRNA content. The new hGMSC-derived iPS line demonstrated to be pluripotent in all aspects, thus representing an innovative dynamic platform for personalized tissue regeneration.

Unveiling the multifaceted roles of microRNAs in extracellular vesicles derived from mesenchymal stem cells: implications in tumor progression and therapeutic interventions

Mesenchymal stem/stromal cells (MSCs) have the capacity to migrate to tumor sites in vivo and transmit paracrine signals by secreting extracellular vesicles (EVs) to regulate tumor biological behaviors. MSC-derived EVs (MSC-EVs) have similar tumor tropism and pro- or anti-tumorigenesis as their parental cells and exhibit superior properties in drug delivery. MSC-EVs can transfer microRNAs (miRNAs) to tumor cells, thereby manipulating multiple key cancer-related pathways, and further playing a vital role in the tumor growth, metastasis, drug resistance and other aspects. In addition, tumor cells can also influence the behaviors of MSCs in the tumor microenvironment (TME), orchestrating this regulatory process via miRNAs in EVs (EV-miRNAs). Clarifying the specific mechanism by which MSC-derived EV-miRNAs regulate tumor progression, as well as investigating the roles of EV-miRNAs in the TME will contribute to their applications in tumor pharmacotherapy. This article mainly reviews the multifaceted roles and mechanism of miRNAs in MSC-EVs affecting tumor progression, the crosstalk between MSCs and tumor cells caused by EV-miRNAs in the TME. Eventually, the clinical applications of miRNAs in MSC-EVs in tumor therapeutics are illustrated.

Therapeutic application of mesenchymal stem cell-derived exosomes in skin wound healing

Wound healing is a complicated obstacle, especially for chronic wounds. Mesenchymal stem cell-derived exosomes may be a promising cell-free approach for treating skin wound healing. Exosomes can accelerate wound healing by attenuating inflammation, promoting angiogenesis, cell proliferation, extracellular matrix production and remodeling. However, many issues, such as off-target effects and high degradation of exosomes in wound sites need to be addressed before applying into clinical therapy. Therefore, the bioengineering technology has been introduced to modify exosomes with greater stability and specific therapeutic property. To prolong the function time and the local concentration of exosomes in the wound bed, the use of biomaterials to load exosomes emerges as a promising strategy. In this review, we summarize the biogenesis and characteristics of exosomes, the role of exosomes in wound healing, and the therapeutic applications of modified-exosomes in wound healing. The challenges and prospects of exosomes in wound healing are also discussed.

Galectin-1-producing mesenchymal stem cells restrain the proliferation of T lymphocytes from patients with systemic lupus erythematosus

INTRODUCTION

Bone marrow mesenchymal stem cell (BMMSC) transplantation is beneficial in treating Systemic lupus erythematosus (SLE); however, the underlying mechanism remains elusive. This study investigates the role of BMMSCs in regulating lymphocyte proliferation and cell cycle progression during SLE and delves into the contribution of BMMSC-produced galectin-1.

METHODS

BMMSCs were co-cultured with T lymphocytes to assess their impact on suppressing CD4+ T cells in SLE patients. Proliferation and cell cycle distribution of CD4+ T cells were analyzed using flow cytometry. The expression of cell cycle-related proteins, including p21, p27, and cyclin-dependent kinase 2 (CDK2), was investigated through western blotting. Extracellular and intracellular galectin-1 levels were determined via ELISA and flow cytometry. The role of galectin-1 in CD4+ T cell proliferation and cell cycle was evaluated through RNAi-mediated galectin-1 expression disruption in BMMSCs.

RESULTS AND DISCUSSION

BMMSCs effectively inhibited CD4+ T cell proliferation and impeded their cell cycle progression in SLE patients, concurrently resulting in a reduction in CDK2 levels and an increase in p21 and p27 expression. Moreover, BMMSCs expressed a high level of galectin-1 in the co-culture system. Galectin-1 was found to be critical in maintaining the suppressive activity of BMMSCs and restoring the cell cycle of CD4+ T cells.

CONCLUSION

This study demonstrates that BMMSCs suppress the proliferation and influence the cell cycle of CD4+ T cells in SLE patients, an effect mediated by the upregulation of galectin-1 in BMMSCs.

Current perspectives on mesenchymal stem cells as a potential therapeutic strategy for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has emerged as a significant health challenge, characterized by its widespread prevalence, intricate natural progression and multifaceted pathogenesis. Although NAFLD initially presents as benign fat accumulation, it may progress to steatosis, non-alcoholic steatohepatitis, cirrhosis, and hepatocellular carcinoma. Mesenchymal stem cells (MSCs) are recognized for their intrinsic self-renewal, superior biocompatibility, and minimal immunogenicity, positioning them as a therapeutic innovation for liver diseases. Therefore, this review aims to elucidate the potential roles of MSCs in alleviating the progression of NAFLD by alteration of underlying molecular pathways, including glycolipid metabolism, inflammation, oxidative stress, endoplasmic reticulum stress, and fibrosis. The insights are expected to provide further understanding of the potential of MSCs in NAFLD therapeutics, and support the development of MSC-based therapy in the treatment of NAFLD.

Optimization strategies for mesenchymal stem cell-based analgesia therapy: a promising therapy for pain management

Pain is a very common and complex medical problem that has a serious impact on individuals' physical and mental health as well as society. Non-steroidal anti-inflammatory drugs and opioids are currently the main drugs used for pain management, but they are not effective in controlling all types of pain, and their long-term use can cause adverse effects that significantly impair patients' quality of life. Mesenchymal stem cells (MSCs) have shown great potential in pain treatment. However, limitations such as the low proliferation rate of MSCs in vitro and low survival rate in vivo restrict their analgesic efficacy and clinical translation. In recent years, researchers have explored various innovative approaches to improve the therapeutic effectiveness of MSCs in pain treatment. This article reviews the latest research progress of MSCs in pain treatment, with a focus on methods to enhance the analgesic efficacy of MSCs, including engineering strategies to optimize the in vitro culture environment of MSCs and to improve the in vivo delivery efficiency of MSCs. We also discuss the unresolved issues to be explored in future MSCs and pain research and the challenges faced by the clinical translation of MSC therapy, aiming to promote the optimization and clinical translation of MSC-based analgesia therapy.

Stem Cell Secretions as a Potential Therapeutic Agent for Autism Spectrum Disorder: A Narrative Review

Autism spectrum disorder (ASD) is a neurodevelopmental illness characterized by impaired social interaction and restricted repetitive behaviors or interests. The rising prevalence of ASD diagnosis has triggered a surge in research into investigating the underlying neuropathological processes and finding new therapeutic approaches. ASD is characterized by neuroinflammation and dysregulation of neuro-immune cross-talk, which suggests that stem cell treatment might be a potential therapeutic approach. The beneficial and restorative effects of stem cells are mainly due to their paracrine activity, in which stem cells generate and release extracellular vesicles such as exosomes and distinct secreted non-vesicle soluble proteins, including, growth factors, chemokines, cytokines, and immunomodulatory molecules referred to as the Secretome. In this paper, we reviewed the existing research exploring the therapeutic potential of stem cell secretome focusing on their role in addressing ASD pathology. Furthermore, we proposed a comprehensive mechanism of action for stem cell secretions, encompassing the broader secretome as well as the specific contribution of exosomes, in alleviating ASD neuropathology. Across the reviewed studies, exosomes and secreted soluble factors of the transplanted stem cell demonstrate a potential efficacy in ameliorating autistic-like behaviors. The proposed mechanism of action involves the modulation of signaling pathways implicated in neuroinflammation, angiogenesis, cellular apoptosis, and immunomodulation.

Stem cell-derived exosomes as a potential therapy for schistosomal hepatic fibrosis in experimental animals

Schistosomiasis is a neglected tropical disease. Egg-induced granuloma formation and tissue fibrosis are the main causes of the high morbidity and mortality of schistosomiasis. Mesenchymal stem cells (MSCs)-derived exosomes play an important role with a superior safety profile than MSCs in the treatment of liver fibrosis. Therefore, the aim of this study was to investigate the potential therapeutic effect of MSCs-derived exosomes on schistosomal hepatic fibrosis. Exosomes were isolated from bone marrow MSCs and characterized. A total of 85 mice were divided into four groups: group I (control group), group II (PZQ group) infected and treated with PZQ, group III (EXO group) infected and treated with MSCs-derived exosomes and group IV (PZQ+EXO group) infected and treated with both PZQ and MSCs-derived exosomes. Assessment of treatment efficacy was evaluated by histopathological and immunohistochemical examination of liver sections by proliferating cell nuclear antigen (PCNA) and nuclear factor-κB (NF-κB). The results showed significant reduction of the number and diameter of hepatic granulomas, hepatic fibrosis, upregulation of PCNA expression and reduction of NF-κB expression in EXO and PZQ+EXO groups as compared to other groups at all durations post infection. Additionally, more improvement was observed in PZQ+EXO group. In conclusion, MSCs-derived exosomes are a promising agent for the treatment of schistosomal hepatic fibrosis, and their combination with PZQ shows a synergistic action including antifibrotic and anti-inflammatory effects. However, further studies are required to establish their functional components and their mechanisms of action.

The mammosphere-derived epithelial cell secretome modulates neutrophil functions in the bovine model

Background

Innovative therapies against bacterial infections are needed. One approach is to focus on host-directed immunotherapy (HDT), with treatments that exploit natural processes of the host immune system. The goals of this type of therapy are to stimulate protective immunity while minimizing inflammation-induced tissue damage. We use non-traditional large animal models to explore the potential of the mammosphere-derived epithelial cell (MDEC) secretome, consisting of all bioactive factors released by the cells, to modulate host immune functions. MDEC cultures are enriched for mammary stem and progenitor cells and can be generated from virtually any mammal. We previously demonstrated that the bovine MDEC secretome, collected and delivered as conditioned medium (CM), inhibits the growth of bacteria in vitro and stimulates functions related to tissue repair in cultured endothelial and epithelial cells.

Methods

The immunomodulatory effects of the bovine MDEC secretome on bovine neutrophils, an innate immune cell type critical for resolving bacterial infections, were determined in vitro using functional assays. The effects of MDEC CM on neutrophil molecular pathways were explored by evaluating the production of specific cytokines by neutrophils and examining global gene expression patterns in MDEC CM-treated neutrophils. Enzyme linked immunosorbent assays were used to determine the concentrations of select proteins in MDEC CM and siRNAs were used to reduce the expression of specific MDEC-secreted proteins, allowing for the identification of bioactive factors modulating neutrophil functions.

Results

Neutrophils exposed to MDEC secretome exhibited increased chemotaxis and phagocytosis and decreased intracellular reactive oxygen species and extracellular trap formation, when compared to neutrophils exposed to control medium. C-X-C motif chemokine 6, superoxide dismutase, peroxiredoxin-2, and catalase, each present in the bovine MDEC secretome, were found to modulate neutrophil functions.

Conclusion

The MDEC secretome administered to treat bacterial infections may increase neutrophil recruitment to the site of infection, stimulate pathogen phagocytosis by neutrophils, and reduce neutrophil-produced ROS accumulation. As a result, pathogen clearance might be improved and local inflammation and tissue damage reduced.

Equine Corneal Wound Healing Using Mesenchymal Stem Cell Secretome: Case Report

Corneal ulcers are a common and potentially vision-threatening condition in horses that can be challenging to treat with conventional therapies alone. This case report describes the successful treatment of a non-healing corneal ulcer in a 28-year-old Hispano-Bretón mare using the secretome derived from adipose tissue-derived mesenchymal stem cells (ASCs). Despite initial treatment with antibiotics, anti-inflammatory drugs, and surgical debridement, the corneal ulcer failed to heal properly, exhibiting persistent epithelial defects and stromal complications. As an alternative regenerative approach, the ASC secretome, a rich source of trophic factors, cytokines, and extracellular vesicles, was topically administered to the affected eye. Remarkably, within one week of secretome treatment, the clinical signs of blepharospasm and epiphora resolved, and the corneal ulcer exhibited complete re-epithelialization, regained transparency, and reduced neovascularization. No recurrence was observed during the 1.5-year follow-up period. This case highlights the potential therapeutic benefits of the ASC secretome in promoting corneal wound healing and suggests its promise as a novel cell-free therapy for treating refractory corneal ulcers in horses.

Role of Adipose-Derived Mesenchymal Stem Cells in Bone Regeneration

Bone regeneration involves multiple factors such as tissue interactions, an inflammatory response, and vessel formation. In the event of diseases, old age, lifestyle, or trauma, bone regeneration can be impaired which could result in a prolonged healing duration or requiring an external intervention for repair. Currently, bone grafts hold the golden standard for bone regeneration. However, several limitations hinder its clinical applications, e.g., donor site morbidity, an insufficient tissue volume, and uncertain post-operative outcomes. Bone tissue engineering, involving stem cells seeded onto scaffolds, has thus been a promising treatment alternative for bone regeneration. Adipose-derived mesenchymal stem cells (AD-MSCs) are known to hold therapeutic value for the treatment of various clinical conditions and have displayed feasibility and significant effectiveness due to their ease of isolation, non-invasive, abundance in quantity, and osteogenic capacity. Notably, in vitro studies showed AD-MSCs holding a high proliferation capacity, multi-differentiation potential through the release of a variety of factors, and extracellular vesicles, allowing them to repair damaged tissues. In vivo and clinical studies showed AD-MSCs favoring better vascularization and the integration of the scaffolds, while the presence of scaffolds has enhanced the osteogenesis potential of AD-MSCs, thus yielding optimal bone formation outcomes. Effective bone regeneration requires the interplay of both AD-MSCs and scaffolds (material, pore size) to improve the osteogenic and vasculogenic capacity. This review presents the advances and applications of AD-MSCs for bone regeneration and bone tissue engineering, focusing on the in vitro, in vivo, and clinical studies involving AD-MSCs for bone tissue engineering.

Insights into the role of mesenchymal stem cells in cutaneous medical aesthetics: from basics to clinics

With the development of the economy and the increasing prevalence of skin problems, cutaneous medical aesthetics are gaining more and more attention. Skin disorders like poor wound healing, aging, and pigmentation have an impact not only on appearance but also on patients with physical and psychological issues, and even impose a significant financial burden on families and society. However, due to the complexities of its occurrence, present treatment options cannot produce optimal outcomes, indicating a dire need for new and effective treatments. Mesenchymal stem cells (MSCs) and their secretomics treatment is a new regenerative medicine therapy that promotes and regulates endogenous stem cell populations and/or replenishes cell pools to achieve tissue homeostasis and regeneration. It has demonstrated remarkable advantages in several skin-related in vivo and in vitro investigations, aiding in the improvement of skin conditions and the promotion of skin aesthetics. As a result, this review gives a complete description of recent scientific breakthroughs in MSCs for skin aesthetics and the limitations of their clinical applications, aiming to provide new ideas for future research and clinical transformation.

A comprehensive insight into the immunomodulatory role of MSCs-derived exosomes (MSC-Exos) through modulating pattern-recognition receptors (PRRs)

Mesenchymal stem cell-derived exosomes (MSC-Exos) are emerging as remarkable agents in the field of immunomodulation with vast potential for diagnosing and treating various diseases, including cancer and autoimmune disorders. These tiny vesicles are laden with a diverse cargo encompassing proteins, nucleic acids, lipids, and bioactive molecules, offering a wealth of biomarkers and therapeutic options. MSC-Exos exhibit their immunomodulatory prowess by skillfully regulating pattern-recognition receptors (PRRs). They conduct a symphony of immunological responses, modulating B-cell activities, polarizing macrophages toward anti-inflammatory phenotypes, and fine-tuning T-cell activity. These interactions have profound implications for precision medicine, cancer immunotherapy, autoimmune disease management, biomarker discovery, and regulatory approvals. MSC-Exos promises to usher in a new era of tailored therapies, personalized diagnostics, and more effective treatments for various medical conditions. As research advances, their transformative potential in healthcare becomes increasingly evident.

Utilizing stem cell-secreted molecules as a versatile toolbox for skin regenerative medicine

Stem cells are recognized as an important target and tool in regenerative engineering. In this study, we explored the feasibility of engineering amniotic fluid-derived mesenchymal stem cell-secreted molecules (afMSC-SMs) as a versatile bioactive material for skin regenerative medicine applications in a time- and cost-efficient and straightforward manner. afMSC-SMs, obtained in powder form through ethanol precipitation, effectively contributed to preserving the self-renewal capacity and differentiation potential of primary human keratinocytes (pKCs) in a xeno-free environment, offering a potential alternative to traditional culture methods for their long-term in vitro expansion, and allowed them to reconstitute a fully stratified epithelium sheet on human dermal fibroblasts. Furthermore, we demonstrated the flexibility of afMSC-SMs in wound healing and hair regrowth through injectable hydrogel and nanogel-mediated transdermal delivery systems, respectively, expanding the pool of regenerative applications. This cell-free approach may offer several potential advantages, including streamlined manufacturing processes, scalability, controlled formulation, longer shelf lives, and mitigation of risks associated with living cell transplantation. Accordingly, afMSC-SMs could serve as a promising therapeutic toolbox for advancing cell-free regenerative medicine, simplifying their broad applicability in various clinical settings.

Emerging Strategies in Mesenchymal Stem Cell-Based Cardiovascular Therapeutics

Cardiovascular diseases continue to challenge global health, demanding innovative therapeutic solutions. This review delves into the transformative role of mesenchymal stem cells (MSCs) in advancing cardiovascular therapeutics. Beginning with a historical perspective, we trace the development of stem cell research related to cardiovascular diseases, highlighting foundational therapeutic approaches and the evolution of cell-based treatments. Recognizing the inherent challenges of MSC-based cardiovascular therapeutics, which range from understanding the pro-reparative activity of MSCs to tailoring patient-specific treatments, we emphasize the need to refine the pro-regenerative capacity of these cells. Crucially, our focus then shifts to the strategies of the fourth generation of cell-based therapies: leveraging the secretomic prowess of MSCs, particularly the role of extracellular vesicles; integrating biocompatible scaffolds and artificial sheets to amplify MSCs' potential; adopting three-dimensional ex vivo propagation tailored to specific tissue niches; harnessing the promise of genetic modifications for targeted tissue repair; and institutionalizing good manufacturing practice protocols to ensure therapeutic safety and efficacy. We conclude with reflections on these advancements, envisaging a future landscape redefined by MSCs in cardiovascular regeneration. This review offers both a consolidation of our current understanding and a view toward imminent therapeutic horizons.

Mesenchymal stem cell secretome for regenerative medicine: Where do we stand?

BACKGROUND

Mesenchymal stem cell (MSC)-based therapies have yielded beneficial effects in a broad range of preclinical models and clinical trials for human diseases. In the context of MSC transplantation, it is widely recognized that the main mechanism for the regenerative potential of MSCs is not their differentiation, with in vivo data revealing transient and low engraftment rates. Instead, MSCs therapeutic effects are mainly attributed to its secretome, i.e., paracrine factors secreted by these cells, further offering a more attractive and innovative approach due to the effectiveness and safety of a cell-free product.

AIM OF REVIEW

In this review, we will discuss the potential benefits of MSC-derived secretome in regenerative medicine with particular focus on respiratory, hepatic, and neurological diseases. Both free and vesicular factors of MSC secretome will be detailed. We will also address novel potential strategies capable of improving their healing potential, namely by delivering important regenerative molecules according to specific diseases and tissue needs, as well as non-clinical and clinical studies that allow us to dissect their mechanisms of action.

KEY SCIENTIFIC CONCEPTS OF REVIEW

MSC-derived secretome includes both soluble and non-soluble factors, organized in extracellular vesicles (EVs). Importantly, besides depending on the cell origin, the characteristics and therapeutic potential of MSC secretome is deeply influenced by external stimuli, highlighting the possibility of optimizing their characteristics through preconditioning approaches. Nevertheless, the clarity around their mechanisms of action remains ambiguous, whereas the need for standardized procedures for the successful translation of those products to the clinics urges.

Mesenchymal stem cells-macrophages crosstalk and myeloid malignancy

As major components of the tumor microenvironment, both mesenchymal stem cells (MSCs) and macrophages can be remodelled and exhibit different phenotypes and functions during tumor initiation and progression. In recent years, increasing evidence has shown that tumor-associated macrophages (TAMs) play a crucial role in the growth, metastasis, and chemotherapy resistance of hematological malignancies, and are associated with poor prognosis. Consequently, TAMs have emerged as promising therapeutic targets. Notably, MSCs exert a profound influence on modulating immune cell functions such as macrophages and granulocytes, thereby playing a crucial role in shaping the immunosuppressive microenvironment surrounding tumors. However, in hematological malignancies, the cellular and molecular mechanisms underlying the interaction between MSCs and macrophages have not been clearly elucidated. In this review, we provide an overview of the role of TAMs in various common hematological malignancies, and discuss the latest advances in understanding the interaction between MSCs and macrophages in disease progression. Additionally, potential therapeutic approaches targeting this relationship are outlined.

Exosome-loaded decellularized tissue: Opening a new window for regenerative medicine

Mesenchymal stem cell-derived exosomes (MSCs-EXO) have received a lot of interest recently as a potential therapeutic tool in regenerative medicine. Extracellular vesicles (EVs) known as exosomes (EXOs) are crucial for cell-cell communication throughout a variety of activities including stress response, aging, angiogenesis, and cell differentiation. Exploration of the potential use of EXOs as essential therapeutic effectors of MSCs to encourage tissue regeneration was motivated by success in the field of regenerative medicine. EXOs have been administered to target tissues using a variety of methods, including direct, intravenous, intraperitoneal injection, oral delivery, and hydrogel-based encapsulation, in various disease models. Despite the significant advances in EXO therapy, various methods are still being researched to optimize the therapeutic applications of these nanoparticles, and it is not completely clear which approach to EXO administration will have the greatest effects. Here, we will review emerging developments in the applications of EXOs loaded into decellularized tissues as therapeutic agents for use in regenerative medicine in various tissues.

The potency of mesenchymal stem/stromal cells: does donor sex matter?

Mesenchymal stem/stromal cells (MSCs) are a promising therapeutic tool in cell therapy and tissue engineering because of their multi-lineage differentiation capacity, immunomodulatory effects, and tissue protective potential. To achieve optimal results as a therapeutic tool, factors affecting MSC potency, including but not limited to cell source, donor age, and cell batch, have been investigated. Although the sex of the donor has been attributed as a potential factor that can influence MSC potency and efficacy, the impact of donor sex on MSC characteristics has not been carefully investigated. In this review, we summarize published studies demonstrating donor-sex-related MSC heterogeneity and emphasize the importance of disclosing donor sex as a key factor affecting MSC potency in cell therapy.

Molecular Mechanisms Responsible for the Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Lung Fibrosis

Mesenchymal stem cell-derived exosomes (MSC-Exos) are nano-sized extracellular vesicles which contain various MSC-sourced anti-fibrotic, immunoregulatory and angio-modulatory proteins (growth factors, immunoregulatory cytokines, chemokines), lipids, and nucleic acids (messenger RNA and microRNAs). Due to their lipid envelope, MSC-Exos easily by-pass all barriers in the body and deliver their cargo directly in target cells, modulating their viability, proliferation, phenotype and function. The results obtained in recently published experimental studies demonstrated beneficial effects of MSC-Exos in the treatment of lung fibrosis. MSC-Exos reduced activation of fibroblasts and prevented their differentiation in myofibroblasts. By delivering MSC-sourced immunoregulatory factors in lung-infiltrated monocytes and T cells, MSC-Exos modulate their function, alleviating on-going inflammation and fibrosis. MSC-Exos may also serve as vehicles for the target delivery of anti-fibrotic and immunomodulatory agents, enabling enhanced attenuation of lung fibrosis. Although numerous pre-clinical studies have demonstrated the therapeutic potential of MSC-Exos in the treatment of pulmonary fibrosis, there are several challenges that currently hinder their clinical implementation. Therefore, in this review article, we summarized current knowledge and we discussed future perspectives regarding molecular and cellular mechanisms which were responsible for the anti-fibrotic, anti-inflammatory and immunoregulatory properties of MSC-Exos, paving the way for their clinical use in the treatment of lung fibrosis.

Human umbilical cord mesenchymal stem cell-derived exosomes ameliorate renal fibrosis in diabetic nephropathy by targeting Hedgehog/SMO signaling

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease globally. Currently, there are no effective drugs for the treatment of DN. Although several studies have reported the therapeutic potential of mesenchymal stem cells, the underlying mechanisms remain largely unknown. Here, we report that both human umbilical cord MSCs (UC-MSCs) and UC-MSC-derived exosomes (UC-MSC-exo) attenuate kidney damage, and inhibit epithelial-mesenchymal transition (EMT) and renal fibrosis in streptozotocin-induced DN rats. Strikingly, the Hedgehog receptor, smoothened (SMO), was significantly upregulated in the kidney tissues of DN patients and rats, and positively correlated with EMT and renal fibrosis. UC-MSC and UC-MSC-exo treatment resulted in decrease of SMO expression. In vitro co-culture experiments revealed that UC-MSC-exo reduced EMT of tubular epithelial cells through inhibiting Hedgehog/SMO pathway. Collectively, UC-MSCs inhibit EMT and renal fibrosis by delivering exosomes and targeting Hedgehog/SMO signaling, suggesting that UC-MSCs and their exosomes are novel anti-fibrotic therapeutics for treating DN.

Extracellular vesicles are key players in mesenchymal stem cells' dual potential to regenerate and modulate the immune system

MSCs are used for treatment of inflammatory conditions or for regenerative purposes. MSCs are complete cells and allogenic transplantation is in principle possible, but mostly autologous use is preferred. In recent years, it was discovered that cells secrete extracellular vesicles. These are active budded off vesicles that carry a cargo. The cargo can be miRNA, protein, lipids etc. The extracellular vesicles can be transported through the body and fuse with target cells. Thereby, they influence the phenotype and modulate the disease. The extracellular vesicles have, like the MSCs, immunomodulatory or regenerative capacities. This review will focus on those features of extracellular vesicles and discuss their dual role. Besides the immunomodulation, the regeneration will concentrate on bone, cartilage, tendon, vessels and nerves. Current clinical trials with extracellular vesicles for immunomodulation and regeneration that started in the last five years are highlighted as well. In summary, extracellular vesicles have a great potential as disease modulating entity and treatment. Their dual characteristics need to be taken into account and often are both important for having the best effect.

Mesenchymal stem cell-derived exosomes: Characteristics and applications in disease pathology and management

Mesenchymal stem cells (MSCs) possess a role in tissue regeneration and homeostasis because of inherent immunomodulatory capacity and the production of factors that encourage healing. There is substantial evidence that MSCs' therapeutic efficacy is primarily determined by their paracrine function including in cancers. Extracellular vesicles (EVs) are basic paracrine effectors of MSCs that reside in numerous bodily fluids and cell homogenates and play an important role in bidirectional communication. MSC-derived EVs (MSC-EVs) offer a wide range of potential therapeutic uses that exceed cell treatment, while maintaining protocell function and having less immunogenicity. We describe characteristics and isolation methods of MSC-EVs, and focus on their therapeutic potential describing its roles in tissue repair, anti-fibrosis, and cancer with an emphasis on the molecular mechanism and immune modulation and clinical trials. We also explain current understanding and challenges in the clinical applications of MSC-EVs as a cell free therapy.

Research progress in cell therapy for oral diseases: focus on cell sources and strategies to optimize cell function

In recent years, cell therapy has come to play an important therapeutic role in oral diseases. This paper reviews the active role of mesenchymal stem cells, immune cell sources, and other cells in oral disorders, and presents data supporting the role of cell therapy in oral disorders, including bone and tooth regeneration, oral mucosal disorders, oral soft tissue defects, salivary gland dysfunction, and orthodontic tooth movement. The paper will first review the progress of cell optimization strategies for oral diseases, including the use of hormones in combination with stem cells, gene-modified regulatory cells, epigenetic regulation of cells, drug regulation of cells, cell sheets/aggregates, cell-binding scaffold materials and hydrogels, nanotechnology, and 3D bioprinting of cells. In summary, we will focus on the therapeutic exploration of these different cell sources in oral diseases and the active application of the latest cell optimization strategies.

Exosome-Mediated Antigen Delivery: Unveiling Novel Strategies in Viral Infection Control and Vaccine Design

Exosomes are small subtypes of extracellular vesicles (EVs) naturally released by different types of cells into their environment. Their physiological roles appear to be multiple, yet many aspects of their biological activities remain to be understood. These vesicles can transport and deliver a variety of cargoes and may serve as unconventional secretory vesicles. Thus, they play a crucial role as important vectors for intercellular communication and the maintenance of homeostasis. Exosome production and content can vary under several stresses or modifications in the cell microenvironment, influencing cellular responses and stimulating immunity. During infectious processes, exosomes are described as double-edged swords, displaying both beneficial and detrimental effects. Owing to their tractability, the analysis of EVs from multiple biofluids has become a booming tool for monitoring various pathologies, from infectious to cancerous origins. In this review, we present an overview of exosome features and discuss their particular and ambiguous functions in infectious contexts. We then focus on their properties as diagnostic or therapeutic tools. In this regard, we explore the capacity of exosomes to vectorize immunogenic viral antigens and their function in mounting adaptive immune responses. As exosomes provide interesting platforms for antigen presentation, we further review the available data on exosome engineering, which enables peptides of interest to be exposed at their surface. In the light of all these data, exosomes are emerging as promising avenues for vaccine strategies.

A Review of the Use of Extracellular Vesicles in the Treatment of Neonatal Diseases: Current State and Problems with Translation to the Clinic

Neonatal disorders, particularly those resulting from prematurity, pose a major challenge in health care and have a significant impact on infant mortality and long-term child health. The limitations of current therapeutic strategies emphasize the need for innovative treatments. New cell-free technologies utilizing extracellular vesicles (EVs) offer a compelling opportunity for neonatal therapy by harnessing the inherent regenerative capabilities of EVs. These nanoscale particles, secreted by a variety of organisms including animals, bacteria, fungi and plants, contain a repertoire of bioactive molecules with therapeutic potential. This review aims to provide a comprehensive assessment of the therapeutic effects of EVs and mechanistic insights into EVs from stem cells, biological fluids and non-animal sources, with a focus on common neonatal conditions such as hypoxic-ischemic encephalopathy, respiratory distress syndrome, bronchopulmonary dysplasia and necrotizing enterocolitis. This review summarizes evidence for the therapeutic potential of EVs, analyzes evidence of their mechanisms of action and discusses the challenges associated with the implementation of EV-based therapies in neonatal clinical practice.