Mesenchymal stem cell exosomes

Current Advances and Future Perspectives on Mesenchymal Stem Cell-Derived Extracellular Vesicles in Alzheimer's Disease

The incidence of Alzheimer's disease (AD) has been increasing in recent years as the world's population ages, which poses a significant challenge to public health. Due to the complexity of pathogenesis of AD, currently there is no effective treatment for it. In recent years, cell and gene therapy has attracted widespread attention in the treatment of neurodegenerative diseases. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) represent a novel cell-free therapy with numerous advantages over cell-based therapies owing to their low immunogenicity and high safety profile. We summarize recent progress in the application of EVs for treating AD and the specific mechanisms and outline the underlying mechanisms. We also explore various methods for optimizing the function of MSC-EVs, including gene editing, modifying stem cell culture conditions and peptide modification. In addition, we discuss the therapeutic potentials of MSC-EVs, as well as the obstacles that currently impede their clinical utilization.

Exosomes derived from bone marrow mesenchymal stem cell preconditioned by low-intensity pulsed ultrasound stimulation promote bone-tendon interface fibrocartilage regeneration and ameliorate rotator cuff fatty infiltration

Background

Fibrovascular scar healing of bone-tendon interface (BTI) instead of functional fibrocartilage regeneration is the main concern associated with unsatisfactory prognosis in rotator cuff repair. Mesenchymal stem cells (MSCs) exosomes have been reported to be a new promising cell-free approach for rotator cuff healing. Whereas, controversies abound in whether exosomes of native MSCs alone can effectively induce chondrogenesis.

Purpose

To explore the effect of exosomes derived from low-intensity pulsed ultrasound stimulation (LIPUS)-preconditioned bone marrow mesenchymal stem cells (LIPUS-BMSC-Exos) or un-preconditioned BMSCs (BMSC-Exos) on rotator cuff healing and the underlying mechanism.

Methods

C57BL/6 mice underwent unilateral supraspinatus tendon detachment and repair were randomly assigned to saline, BMSCs-Exos or LIPUS-BMSC-Exos injection therapy. Histological, immunofluorescent and biomechanical tests were detected to investigate the effect of exosomes injection on BTI healing and muscle fatty infiltration of the repaired rotator cuff. In vitro, native BMSCs were incubated with BMSC-Exos or LIPUS-BMSC-Exos and then chondrogenic/adipogenic differentiation were observed. Further, quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the chondrogenesis/adipogenesis-related miRNA profiles of LIPUS-BMSC-Exos and BMSC-Exos. The chondrogenic/adipogenic potential of the key miRNA was verified through function recover test with its mimic and inhibitor.

Results

The results indicated that the biomechanical properties of the supraspinatus tendon-humeral junction were significantly improved in the LIPUS-BMSC-Exos group than that of the BMSCs-Exos group. The LIPUS-BMSC-Exos group also exhibited a higher histological score and more newly regenerated fibrocartilage at the repair site at postoperative 2 and 4 weeks and less fatty infiltration at 4 weeks than the BMSCs-Exos group. In vitro, co-culture of BMSCs with LIPUS-BMSC-Exos could significantly promote BMSCs chondrogenic differentiation and inhibit adipogenic differentiation. Subsequently, qRT-PCR revealed significantly higher enrichment of chondrogenic miRNAs and less enrichment of adipogenic miRNAs in LIPUS-BMSC-Exos compared with BMSC-Exos. Moreover, we demonstrated that this chondrogenesis-inducing potential was primarily attributed to miR-140, one of the most abundant miRNAs in LIPUS-BMSC-Exos.

Conclusion

LIPUS-preconditioned BMSC-Exos can effectively promote BTI fibrocartilage regeneration and ameliorate supraspinatus fatty infiltration by positive regulation of pro-chondrogenesis and anti-adipogenesis, which was primarily through delivering miR-140.

The translational potential of this article

These findings propose an innovative "LIPUS combined Exosomes strategy" for rotator cuff healing which combines both physiotherapeutic and biotherapeutic advantages. This strategy possesses a good translational potential as a local injection of LIPUS preconditioned BMSC-derived Exos during operation can be not only efficient for promoting fibrocartilage regeneration and ameliorating rotator cuff fatty infiltration, but also time-saving, simple and convenient for patients.

The functions of exosomes targeting astrocytes and astrocyte-derived exosomes targeting other cell types

Astrocytes are the most abundant glial cells in the central nervous system; they participate in crucial biological processes, maintain brain structure, and regulate nervous system function. Exosomes are cell-derived extracellular vesicles containing various bioactive molecules including proteins, peptides, nucleotides, and lipids secreted from their cellular sources. Increasing evidence shows that exosomes participate in a communication network in the nervous system, in which astrocyte-derived exosomes play important roles. In this review, we have summarized the effects of exosomes targeting astrocytes and the astrocyte-derived exosomes targeting other cell types in the central nervous system. We also discuss the potential research directions of the exosome-based communication network in the nervous system. The exosome-based intercellular communication focused on astrocytes is of great significance to the biological and/or pathological processes in different conditions in the brain. New strategies may be developed for the diagnosis and treatment of neurological disorders by focusing on astrocytes as the central cells and utilizing exosomes as communication mediators.

Scaffold loaded LPS-hUCMSC-sEVs promote Osteo/odontogenic differentiation and angiogenic potential of hDPSCs

OBJECTIVE

The formation of dentin-pulp complex determines the success of vital pulp therapy. Human umbilical cord mesenchymal stem cell-derived small extracellular vesicles (hUCMSC-sEVs) appeared to have stronger effect in anti-inflammatory and promoting the proliferation and migration of human dental pulp stem cells (hDPSCs). Moreover, Lipopolysaccharides (LPS) pretreatment can enhance the rapeutic potency of extracellular vesicles. LPS pretreatment hUCMSC-sEVs have the potential to regenerate the dentin-pulp complex by recruiting hDPSCs. This paper aims to develop collagen sponge/self-assembling peptide nanofiber scaffold (CS/SAPNS) composite scaffold loaded with LPS pretreatment hUCMSC-sEVs (CS/SAPNS-sEVs), and assess the release characteristics of hUCMSC-sEVs and the effect of this composite scaffold on osteo/odontogenic differentiation and angiogenic potential in hDPSCs.

METHODS

LPS pretreatment hUCMSC-sEVs (LPS-hUCMSC-sEVs) were mixed with self-assembling peptide hydrogel and loaded onto collagen sponge to obtain the CS/SAPNS-sEVs. BCA assay, nanoparticle analysis, transmission electron microscopy and laser confocal microscopy were used to investigate the characteristics of LPS-hUCMSC-sEVs loaded on CS/SAPNS. Osteo/odontogenic differentiation ability of hDPSCs were analyzed by ALP stainning, alizarin red staining. RT-PCR and Western blot analysis were performed to confirm the levels of osteo/odontogenic factors and angiogenic factors, and the involvement of NF-κB pathway was verified by immunocytochemical staining and Western blot analysis.

RESULTS

CS/SAPNS could control LPS-hUCMSC-sEVs release for 7 days and keep their structural integrity. CS/SAPNS-sEVs promoted deposition of calcified nodules and expression of osteogenic/odontogenic and angiogenic factors in hDPSCs. On the contrary, inhibition of the NF-κB pathway down-regulated the expression of CS/SAPNS-sEVs-regulated osteo/odontogenic and angiogenic factors.

CONCLUSION

CS/SNAPS could be used as scaffold for LPS-hUCMSC-sEVs, and CS/SAPNS-sEVs may promote osteo/odontogenic differentiation and enhance the angiogenic potential of hDPSCs through activating the NF-κB pathway.

Therapeutic Potential and Mechanisms of Mesenchymal Stem Cell and Mesenchymal Stem Cell-Derived Extracellular Vesicles in Atopic Dermatitis

Atopic dermatitis (AD) is a chronic and inflammatory skin disease with intense itchiness that is highly prevalent worldwide.The pathogenesis of AD is complex and closely related to genetic factors, immunopathogenic factors, environmental factors, and skin infections. Mesenchymal stem cells (MSCs) are non-hematopoietic progenitor cells derived from the mesenchymal stroma. They have anti-inflammatory, anti-apoptotic, and regenerative properties. Numerous studies demonstrate that MSCs can play a therapeutic role in AD by regulating various immune cells, maintaining immune homeostasis, and promoting the repair of damaged tissues. The key mediators for their biological functions are extracellular vesicles (MSC-Evs) and soluble cytokines derived from MSCs. The safety and efficacy of MSCs have been demonstrated in clinical Phase I / IIa trials for AD. This paper provides a comprehensive review of the pathogenesis of AD and the currently published studies on the function of MSCs and MSC-Evs in AD, primarily including the pathogenesis and the immunomodulatory impacts of MSCs and MSC-Evs, along with advancements in clinical studies. It provides insights for comprehending AD pathogenesis and investigating treatments based on MSCs.

Advances in application of hypoxia-preconditioned mesenchymal stem cell-derived exosomes

Mesenchymal stem cells (MSCs) primarily secrete physiologically functional exosomes via paracrine effects that act on various adjacent and distant cells, thus exerting their therapeutic effects. In recent years, hypoxic preconditioning, as a novel MSC culture mode, has emerged as a research hotspot. Many previous studies have shown the role and underlying regulatory mechanisms of hypoxic preconditioning in various diseases, which has provided sufficient reference materials for the MSC research field. Therefore, this review summarizes the progress in application of hypoxia-preconditioned MSC-derived exosomes that substantially increases and improves the biological activity of specific molecules, such as microRNA.

A novel mechanism behind irreversible development of cartilage degradation driven articular cartilage defects revealed by rat model: The chain reaction initiated by extracellular vesicles delivered LOC102546541

BACKGROUND

Articular cartilage defects (ACD) are injuries with a diameter greater than 3 mm, resulting from wear and tear on joints. When the diameter of the defect exceeds 6 mm, it can further damage the surrounding joint cartilage, causing osteoarthritis (OA). Try to explain why OA is an irreversible disease, we hypothesize that damaged articular chondrocytes (DAC) may have reduced capacities to repair cartilage because its extracellular vesicle (EVs) that might directly contribute to OA formation.

METHODS

In this study, DAC-EVs and AC-EVs were isolated using ultracentrifugation. Next-generation sequencing was employed to screen for a pathogenic long non-coding RNA (lncRNA). After verifying its function in vitro, the corresponding small interfering RNA (siRNA) was constructed and loaded into extracellular vesicles, which were then injected into the knee joint cavities of rats.

RESULTS

The results revealed that DAC-EVs packaged lncRNA LOC102546541 acts as a competitive endogenous RNA (ceRNA) of MMP13, down-regulating miR-632. Consequently, the function of MMP13 in degrading the extracellular matrix is enhanced, promoting the development of osteoarthritis.

CONCLUSIONS

This study uncovered a novel mode of OA pathogenesis using rat models, which DAC deliver pathogenic LOC102546541 packaged EVs to normal articular chondrocytes, amplifying the degradation of the extracellular matrix. Nonetheless, the functions of highly homologous human gene of LOC102546541 need to be verified in the future.

The role of mesenchymal stem cells in attenuating inflammatory bowel disease through ubiquitination

Inflammatory bowel disease (IBD), a condition of the digestive tract and one of the autoimmune diseases, is becoming a disease of significant global public health concern and substantial clinical burden. Various signaling pathways have been documented to modulate IBD, but the exact activation and regulatory mechanisms have not been fully clarified; thus, a need for constant exploration of the molecules and pathways that play key roles in the development of IBD. In recent years, several protein post-translational modification pathways, such as ubiquitination, phosphorylation, methylation, acetylation, and glycolysis, have been implicated in IBD. An aberrant ubiquitination in IBD is often associated with dysregulated immune responses and inflammation. Mesenchymal stem cells (MSCs) play a crucial role in regulating ubiquitination modifications through the ubiquitin-proteasome system, a cellular machinery responsible for protein degradation. Specifically, MSCs have been shown to influence the ubiquitination of key signaling molecules involved in inflammatory pathways. This paper reviews the recent research progress in MSC-regulated ubiquitination in IBD, highlighting their therapeutic potential in treating IBD and offering a promising avenue for developing targeted interventions to modulate the immune system and alleviate inflammatory conditions.

Desktop-Stereolithography 3D Printing of a Decellularized Extracellular Matrix/Mesenchymal Stem Cell Exosome Bioink for Vaginal Reconstruction

BACKGROUND

3D-printing is widely used in regenerative medicine and is expected to achieve vaginal morphological restoration and true functional reconstruction. Mesenchymal stem cells-derived exosomes (MSCs-Exos) were applyed in the regeneration of various tissues. The current study aimed to explore the effctive of MSCs-Exos in vaginal reconstruction.

METHODS

In this work, hydrogel was designed using decellularized extracellular matrix (dECM) and gelatin methacrylate (GelMA) and silk fibroin (SF). The biological scaffolds were constructed using desktop-stereolithography. The physicochemical properties of the hydrogels were evaluated; Some experiments have been conducted to evaluate exosomes' effect of promotion vaginal reconstruction and to explore the mechanism in this process.

RESULTS

It was observed that the sustained release property of exosomes in the hydrogel both in vitro and in vitro.The results revealed that 3D scaffold encapsulating exosomes expressed significant effects on the vascularization and musule regeneration of the regenerative vagina tissue. Also, MSCs-Exos strongly promoted vascularization in the vaginal reconstruction of rats, which may through the PI3K/AKT signaling pathway.

CONCLUSION

The use of exosome-hydrogel composites improved the epithelial regeneration of vaginal tissue, increased angiogenesis, and promoted smooth muscle tissue regeneration. 3D-printed, lumenal scaffold encapsulating exosomes might be used as a cell-free alternative treatment strategy for vaginal reconstruction.

Modulation of naïve mesenchymal stromal cells by extracellular vesicles derived from insulin-producing cells: an in vitro study

This study was to determine whether extracellular vesicles (EVs) derived from insulin-producing cells (IPCs) can modulate naïve mesenchymal stromal cells (MSCs) to become insulin-secreting. MSCs were isolated from human adipose tissue. The cells were then differentiated to generate IPCs by achemical-based induction protocol. EVs were retrieved from the conditioned media of undifferentiated (naïve) MSCs (uneducated EVs) and from that of MSC-derived IPCs (educated EVs) by sequential ultracentrifugation. The obtained EVs were co-cultured with naïve MSCs.The cocultured cells were evaluated by immunofluorescence, flow cytometry, C-peptide nanogold silver-enhanced immunostaining, relative gene expression and their response to a glucose challenge.Immunostaining for naïve MSCs cocultured with educated EVs was positive for insulin, C-peptide, and GAD65. By flow cytometry, the median percentages of insulin-andC-peptide-positive cells were 16.1% and 14.2% respectively. C-peptide nanogoldimmunostaining providedevidence for the intrinsic synthesis of C-peptide. These cells released increasing amounts of insulin and C-peptide in response to increasing glucose concentrations. Gene expression of relevant pancreatic endocrine genes, except for insulin, was modest. In contrast, the results of naïve MSCs co-cultured with uneducated exosomes were negative for insulin, C-peptide, and GAD65. These findings suggest that this approach may overcome the limitations of cell therapy.

Exosome prospects in the diagnosis and treatment of non-alcoholic fatty liver disease

The growing prevalence of NAFLD and its global health burden have provoked considerable research on possible diagnostic and therapeutic options for NAFLD. Although various pathophysiological mechanisms and genetic factors have been identified to be associated with NAFLD, its treatment remains challenging. In recent years, exosomes have attracted widespread attention for their role in metabolic dysfunctions and their efficacy as pathological biomarkers. Exosomes have also shown tremendous potential in treating a variety of disorders. With increasing evidence supporting the significant role of exosomes in NAFLD pathogenesis, their theragnostic potential has become a point of interest in NAFLD. Expectedly, exosome-based treatment strategies have shown promise in the prevention and amelioration of NAFLD in preclinical studies. However, there are still serious challenges in preparing, standardizing, and applying exosome-based therapies as a routine clinical option that should be overcome. Due to the great potential of this novel theragnostic agent in NAFLD, further investigations on their safety, clinical efficacy, and application standardization are highly recommended.

Enhancing EV-cell communication through "External Modulation of Cell by EV" (EMCEV)

Mesenchymal stem/stromal cells (MSC) have displayed promising therapeutic potential. Nonetheless, no United States Food and Drug Administration (FDA)-approved MSC product exists due largely to the absence of a reliable potency assay based on the mechanisms of action to ensure consistent efficacy. MSCs are now thought to exert their effects primarily by releasing small extracellular vesicles (sEVs) of 50-200 nm. While non-living MSC-sEV drugs offer distinct advantages over larger, living MSC drugs, elucidating their mechanism of action to develop robust potency assays remains a challenge. A pivotal prelude to elucidating the mechanism of action for MSC-sEVs is how extracellular vesicles (EVs) engage their primary target cells. Given the inherent inefficiencies of processes such as endocytosis, endosomal escape and EV uncoating during cellular internalization, we propose an alternative EV-cell engagement: EMCEV (Extracellular Modulation of Cells by EV). This approach involves extracellular modulation by EV attributes to generate signaling/inhibitory molecules that have the potential to affect many cells within the vicinity, thereby eliciting a more widespread tissue response.

Immunoregulatory paracrine effect of mesenchymal stem cells and mechanism in the treatment of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease caused by chronic inflammation that damages articular cartilage. At present, the treatment of OA includes drug therapy to relieve symptoms and joint replacement therapy for advanced OA. However, these palliatives cannot truly block the progression of the disease from the immunological pathogenesis of OA. In recent years, bone marrow mesenchymal stem cell (BMSC) transplantation has shown great potential in tissue engineering repair. In addition, many studies have shown that BMSC paracrine signals play an important role in the treatment of OA through immune regulation and suppressing inflammation. At present, the mechanism of inflammation-induced OA and the use of BMSC transplantation in joint repair have been reviewed, but the mechanism and significance of BMSC paracrine signals in the treatment of OA have not been fully reviewed. Therefore, this article focused on the latest research progress on the paracrine effects of BMSCs in the treatment of OA and the related mechanisms by which BMSCs secrete cytokines to inhibit the inflammatory response, regulate immune balance, and promote cell proliferation and differentiation. In addition, the application potential of BMSC-Exos as a new type of cell-free therapy for OA is described. This review aimed to provide systematic theoretical support for the clinical application of BMSC transplantation in the treatment of OA.

Ameliorative effects of undifferentiated and differentiated BM-MSCs in MIA-induced osteoarthritic Wistar rats: roles of NF-κB and MMPs signaling pathways

OBJECTIVES

Osteoarthritis (OA) is a degenerative joint condition that is persistent. OA affects millions of people throughout the world. Both people and society are heavily economically burdened by osteoarthritis. There is currently no medication that can structurally alter the OA processes or stop the disease from progressing. Stem cells have the potential to revolutionize medicine due to their capacity to differentiate into chondrocytes, capacity to heal tissues and organs including osteoarthritic joints, and immunomodulatory capabilities. Therefore, the goal of the current investigation was to determine how bone marrow-derived mesenchymal stem cells (BM-MSCs) and chondrogenic differentiated mesenchymal stem cells (CD-MSCs) affected the treatment of OA in rats with monosodium iodoacetate (MIA)-induced osteoarthritis.

METHODS

Male Wistar rats were injected three times with MIA (1 mg)/100 µL isotonic saline to induce osteoarthritis in the ankle joint of the right hind leg. Following the MIA injection, the osteoarthritic rats were given weekly treatments of 1 × 106 BM-MSCs and CD-MSCs into the tail vein for three weeks.

RESULTS

The obtained results showed that in osteoarthritic rats, BM-MSCs and CD-MSCs dramatically decreased ankle diameter measurements, decreased oxidized glutathione (GSSG) level, and boosted glutathione peroxidase (GPx) and glutathione reductase (GR) activities. Additionally, in rats with MIA-induced OA, BM-MSCs and CD-MSCs dramatically boosted interleukin-10 (IL-10) serum levels while considerably decreasing serum anticitrullinated protein antibodies (ACPA), tumour necrosis factor-α (TNF-α), and interleukin-17 (IL-17) levels as well as ankle transforming growth factor-β1 (TGF-β1) expression. Analysis of histology, immunohistochemistry, and western blots in osteoarthritic joints showed that cartilage breakdown and joint inflammation gradually decreased over time.

CONCLUSIONS

It is possible to conclude from these results that BM-MSCs and CD-MSCs have anti-arthritic potential in MIA-induced OA, which may be mediated via inhibitory effects on oxidative stress, MMPs and inflammation through suppressing the NF-κB pathway. In osteoarthritis, using CD-MSCs as a treatment is more beneficial therapeutically than using BM-MSCs.

Mesenchymal Stem Cell-Derived Exosomes as Drug Delivery Vehicles in Disease Therapy

Exosomes are small vesicles containing proteins, nucleic acids, and biological lipids, which are responsible for intercellular communication. Studies have shown that exosomes can be utilized as effective drug delivery vehicles to accurately deliver therapeutic substances to target tissues, enhancing therapeutic effects and reducing side effects. Mesenchymal stem cells (MSCs) are a class of stem cells widely used for tissue engineering, regenerative medicine, and immunotherapy. Exosomes derived from MSCs have special immunomodulatory functions, low immunogenicity, the ability to penetrate tumor tissues, and high yield, which are expected to be engineered into efficient drug delivery systems. Despite the promising promise of MSC-derived exosomes, exploring their optimal preparation methods, drug-loading modalities, and therapeutic potential remains challenging. Therefore, this article reviews the related characteristics, preparation methods, application, and potential risks of MSC-derived exosomes as drug delivery systems in order to find potential therapeutic breakthroughs.

Relieving Macrophage Dysfunction by Inhibiting SREBP2 Activity: A Hypoxic Mesenchymal Stem Cells-Derived Exosomes Loaded Multifunctional Hydrogel for Accelerated Diabetic Wound Healing

Macrophage dysfunction is one of the primary factors leading to the delayed healing of diabetic wounds. Hypoxic bone marrow mesenchymal stem cells-derived exosomes (hyBMSC-Exos) have been shown to play an active role in regulating cellular function through the carried microRNAs. However, the administration of hyBMSC-Exos alone in diabetic wounds usually brings little effect, because the exosomes are inherently unstable and have a short retention time at the wounds. In this study, a multifunctional hydrogel based on gallic acid (GA) conjugated chitosan (Chi-GA) and partially oxidized hyaluronic acid (OHA) is prepared for sustained release of hyBMSC-Exos. The hydrogel not only exhibits needs-satisfying physicochemical properties, but also displays outstanding biological performances such as low hemolysis rate, strong antibacterial capacity, great antioxidant ability, and excellent biocompatibility. It has the ability to boost the stability of hyBMSC-Exos, leading to a continuous and gradual release of the exosomes at wound locations, ultimately enhancing the exosomes' uptake efficiency by target cells. Most importantly, hyBMSC-Exos loaded hydrogel shows an excellent ability to promote diabetic wound healing by regulating macrophage polarization toward M2 phenotype. This may be because exosomal miR-4645-5p and antioxidant property of the hydrogel synergistically inhibit SREBP2 activity in macrophages. This study presents a productive approach for managing diabetic wounds.

Cell-cell communication in stem cells and cancer: Alone but in touch

BACKGROUND

Cellular communication and signaling pathways are fundamental regulators of stem cell and cancer cell behaviors. This review explores the intricate interplay of these pathways in governing cellular behaviors, focusing on their implications for diseases, particularly cancer.

OBJECTIVES

This comprehensive review aims to elucidate the significance of cellular signaling pathways in regulating the behavior of stem cells and cancer cells. It delves into the alterations in these pathways, their impact on cell fate, and their implications for developing diseases, notably cancer. The objective is to underscore the importance of understanding these signaling pathways for developing targeted therapeutic strategies.

METHODS

The review critically analyzes existing literature and research findings concerning the roles of signaling pathways in stem cell behavior regulation, emphasizing their parallels and disparities in cancer cells. It synthesizes information on both direct and indirect modes of cell communication to delineate the complexity of signaling networks.

RESULTS

Direct and indirect modes of cell communication intricately regulate the complex signaling pathways governing stem cell behaviors, influencing differentiation potential and tissue regeneration. Alterations in these pathways significantly impact stem cell fate, contributing to disease pathogenesis, including cancer. Understanding these signaling cascades offers insights into developing targeted therapies, particularly cancer treatment.

CONCLUSION

Understanding the regulation of signaling pathways in stem cells and the specialized subset of cancer stem cells holds promise for innovative therapeutic approaches. By targeting aberrant signaling pathways, tailored interventions may improve treatment outcomes. This review underscores the critical role of signaling pathways in cellular behaviors, offering a pathway toward developing novel, more effective therapies for diverse diseases and disorders.

Small extracellular vesicles derived from human mesenchymal stem cells prevent Th17-dominant neutrophilic airway inflammation via immunoregulation on Th17 cells

Type 17 helper T cells (Th17)-dominant neutrophilic airway inflammation is critical in the pathogenesis of steroid-resistant airway inflammation such as severe asthma. Small extracellular vesicles (sEV) derived from human mesenchymal stem cells (MSCs) display extensive therapeutic effects and advantages in many diseases. However, the role of MSC-sEV in Th17-dominant neutrophilic airway inflammation and the related mechanisms are still poorly studied. Here we found that MSC-sEV significantly alleviated the infiltration of inflammatory cells in peribronchial interstitial tissues and reduced levels of inflammatory cells, especially neutrophils, in bronchoalveolar lavage fluids (BALF) of mice with neutrophilic airway inflammation. Consistently, MSC-sEV significantly decreased levels of IL-17A in BALF and Th17 in lung tissues. Furthermore, we found that labelled MSC-sEV were taken up by human CD4+ T cells most obviously at 12 h after incubation, and distributed mostly in mouse lungs. More importantly, potential signaling pathways involved in the MSC-sEV mediated inhibition of Th17 polarization were found using RNA sequencing. Using Western blot, JAK2-STAT3 pathway was identified as an important role in the inhibition of Th17 polarization by MSC-sEV. We found that proteins in MSC-sEV were mostly involved in the therapeutic effects of MSC-sEV. In total, our study suggested that MSC-sEV could be a potential therapeutic strategy for the treatment of neutrophilic airway inflammation.

Research hotspots and emerging trends of mesenchymal stem cells in cardiovascular diseases: a bibliometric-based visual analysis

Background

Mesenchymal stem cells (MSCs) have important research value and broad application prospects in cardiovascular diseases (CVDs). However, few bibliometric analyses on MSCs in cardiovascular diseases are available. This study aims to provide a thorough review of the cooperation and influence of countries, institutions, authors, and journals in the field of MSCs in cardiovascular diseases, with the provision of discoveries in the latest progress, evolution paths, frontier research hotspots, and future research trends in the regarding field.

Methods

The articles related to MSCs in cardiovascular diseases were retrieved from the Web of Science. The bibliometric study was performed by CiteSpace and VOSviewer, and the knowledge map was generated based on data obtained from retrieved articles.

Results

In our study, a total of 4,852 publications launched before August 31, 2023 were accessed through the Web of Science Core Collection (WoSCC) database via our searching strategy. Significant fluctuations in global publications were observed in the field of MSCs in CVDs. China emerged as the nation with the largest number of publications, yet a shortage of high-quality articles was noted. The interplay among countries, institutions, journals and authors is visually represented in the enclosed figures. Importantly, current research trends and hotspots are elucidated. Cluster analysis on references has highlighted the considerable interest in exosomes, extracellular vesicles, and microvesicles. Besides, keywords analysis revealed a strong emphasis on myocardial infarction, therapy, and transplantation. Treatment methods-related keywords were prominent, while keywords associated with extracellular vesicles gathered significant attention from the long-term perspective.

Conclusion

MSCs in CVDs have become a topic of active research interest, showcasing its latent value and potential. By summarizing the latest progress, identifying the research hotspots, and discussing the future trends in the advancement of MSCs in CVDs, we aim to offer valuable insights for considering research prospects.

Transitioning from static to suspension culture system for large-scale production of xeno-free extracellular vesicles derived from mesenchymal stromal cells

Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) have shown increasing therapeutic potential in the last years. However, large production of EV is required for therapeutic purposes. Thereby, scaling up MSC cultivation in bioreactors is essential to allow culture parameters monitoring. In this study, we reported the establishment of a scalable bioprocess to produce MSC-EV in suspension cultures using spinner flasks and human collagen-coated microcarriers (3D culture system). We compared the EV production in this 3D culture system with the standard static culture using T-flasks (2D culture system). The EV produced in both systems were characterized and quantify by western blotting and nanoparticle tracking analysis. The presence of the typical protein markers CD9, CD63, and CD81 was confirmed by western blotting analyses for EV produced in both culture systems. The cell fold-increase was 5.7-fold for the 3D culture system and 4.6-fold for the 2D culture system, signifying a fold-change of 1.2 (calculated as the ratio of fold-increase 3D to fold-increase 2D). Furthermore, it should be noted that the total cell production in the spinner flask cultures was 4.8 times higher than that in T-flask cultures. The total cell production in the spinner flask cultures was 5.2-fold higher than that in T-flask cultures. While the EV specific production (particles/cell) in T-flask cultures (4.40 ± 1.21 × 108 particles/mL, p < 0.05) was higher compared to spinner flask cultures (2.10 ± 0.04 × 108 particles/mL, p < 0.05), the spinner flask culture system offers scalability, making it capable of producing enough MSC-EV at a large scale for clinical applications. Therefore, we concluded that 3D culture system evaluated here serves as an efficient transitional platform that enables the scaling up of MSC-EV production for therapeutic purposes by utilizing stirred tank bioreactors and maintaining xeno-free conditions.

Multifunctional Nanocarriers for Alzheimer's Disease: Befriending the Barriers

Neurodegenerative diseases (NDDs) have been increasing in incidence in recent years and are now widespread worldwide. Neuronal death is defined as the progressive loss of neuronal structure or function which is closely associated with NDDs and represents the intrinsic features of such disorders. Amyotrophic lateral sclerosis, frontotemporal dementia, Alzheimer's, Parkinson's, and Huntington's diseases (AD, PD, and HD, respectively) are considered neurodegenerative diseases that affect a large number of people worldwide. Despite the testing of various drugs, there is currently no available therapy that can remedy or effectively slow the progression of these diseases. Nanomedicine has the potential to revolutionize drug delivery for the management of NDDs. The use of nanoparticles (NPs) has recently been developed to improve drug delivery efficiency and is currently subjected to extensive studies. Nanoengineered particles, known as nanodrugs, can cross the blood-brain barrier while also being less invasive compared to the most treatment strategies in use. Polymeric, magnetic, carbonic, and inorganic NPs are examples of NPs that have been developed to improve drug delivery efficiency. Primary research studies using NPs to cure AD are promising, but thorough research is needed to introduce these approaches to clinical use. In the present review, we discussed the role of metal-based NPs, polymeric nanogels, nanocarrier systems such as liposomes, solid lipid NPs, polymeric NPs, exosomes, quantum dots, dendrimers, polymersomes, carbon nanotubes, and nanofibers and surfactant-based systems for the therapy of neurodegenerative diseases. In addition, we highlighted nanoformulations such as N-butyl cyanoacrylate, poly(butyl cyanoacrylate), D-penicillamine, citrate-coated peptide, magnetic iron oxide, chitosan (CS), lipoprotein, ceria, silica, metallic nanoparticles, cholinesterase inhibitors, an acetylcholinesterase inhibitors, metal chelators, anti-amyloid, protein, and peptide-loaded NPs for the treatment of AD.

Exosomes Derived from Adipose Stem Cells Enhance Angiogenesis in Diabetic Wound Via miR-146a-5p/JAZF1 Axis

Chronic trauma in diabetes is a leading cause of disability and mortality. Exosomes show promise in tissue regeneration. This study investigates the role of exosomes derived from adipose stem cells (ADSC-Exos) in angiogenesis. MiRNA-seq analysis revealed significant changes in 47 genes in human umbilical vein endothelial cells (HUVECs) treated with ADSC-Exos, with miR-146a-5p highly expressed. MiR-146a-5p mimics enhanced the pro-angiogenic effects of ADSC-Exos, while inhibitors had the opposite effect. JAZF1 was identified as a direct downstream target of miR-146a-5p through bioinformatics, qRT-PCR, and dual luciferase assay. Overexpress of JAZF1 resulted in decreased proliferation, migration, and angiogenic capacity of HUVECs, and reduced VEGFA expression. This study proposes that ADSC-Exos regulate angiogenesis partly via the miR-146a-5p/JAZF1 axis.

Efficacy and safety of mesenchymal stem cell-derived microvesicles in mouse inflammatory arthritis

OBJECTIVE

To determine the effective and safe intravenous doses of mesenchymal stem cells (MSCs)-derived microvesicles (MVs) and to elucidate the possible causes of death in mice receiving high-dose MVs.

METHODS

MVs were isolated from human MSCs by gradient centrifugation. Mice with collagen-induced arthritis were treated with different doses of intravenous MVs or MSCs. Arthritis severity, white blood cell count, and serum C-reactive protein levels were measured. To assess the safety profile of MSCs and MVs, mice were treated with different doses of MSCs and MVs, and LD50 was calculated. Mouse lungs and heart were assessed by live fluorescence imaging, histopathological measurements, and immunohistochemistry to explore the possible causes of death. Serum concentrations of cTnT, cTnI, and CK-MB were determined by ELISA. With the H9C2 cardiomyocyte cell line,  cellular uptake of MVs was observed using confocal microscopy and cell toxicity was assessed by CCK-8 and flow cytometry.

RESULTS

Intravenous treatment with MSCs and MVs alleviated inflammatory arthritis, while high doses of MSCs and MVs were lethal. Mice receiving a maximum dose of MSCs (0.1 mL of MSCs at 109/mL) died immediately, while mice receiving a maximum dose of MVs (0.1 mL of MVs at 1012/mL) exhibited tears, drooling, tachycardia, shortness of breath, unbalanced rollover, bouncing, circular crawling, mania, and death. Some mice died after exhibiting convulsions and other symptoms. All mice died shortly after injecting the maximum dose of MSCs. Histologically, mice receiving high doses of MSCs frequently developed pulmonary embolism, while those receiving high doses of MVs died of myocardial infarction. Consistently, the serum levels of cTnT, cTnI, and CK-MB were significantly increased in the MVs-treated group (P < 0.05). The LD50 of intravenous MVs was 1.60 × 1012/kg. Further, MVs could enter the cell. High doses of MVs induced cell apoptosis, though low concentrations of MVs induced cell proliferation.

CONCLUSIONS

Appropriate dosages of MVs and MSCs are effective treatments for inflammatory arthritis while MVs and MSCs overdose is unsafe by causing cardiopulmonary complications.

Functional and Molecular Analysis of Human Osteoarthritic Chondrocytes Treated with Bone Marrow-Derived MSC-EVs

Osteoarthritis (OA) is a degenerative joint disease, causing impaired mobility. There are currently no effective therapies other than palliative treatment. Mesenchymal stromal cells (MSCs) and their secreted extracellular vesicles (MSC-EVs) have shown promise in attenuating OA progression, promoting chondral regeneration, and modulating joint inflammation. However, the precise molecular mechanism of action driving their beneficial effects has not been fully elucidated. In this study, we analyzed MSC-EV-treated human OA chondrocytes (OACs) to assess viability, proliferation, migration, cytokine and catabolic protein expression, and microRNA and mRNA profiles. We observed that MSC-EV-treated OACs displayed increased metabolic activity, proliferation, and migration compared to the controls. They produced decreased proinflammatory (Il-8 and IFN-γ) and increased anti-inflammatory (IL-13) cytokines, and lower levels of MMP13 protein coupled with reduced expression of MMP13 mRNA, as well as negative microRNA regulators of chondrogenesis (miR-145-5p and miR-21-5p). In 3D models, MSC-EV-treated OACs exhibited enhanced chondrogenesis-promoting features (elevated sGAG, ACAN, and aggrecan). MSC-EV treatment also reversed the pathological impact of IL-1β on chondrogenic gene expression and extracellular matrix component (ECM) production. Finally, MSC-EV-treated OACs demonstrated the enhanced expression of genes associated with cartilage function, collagen biosynthesis, and ECM organization and exhibited a signature of 24 differentially expressed microRNAs, associated with chondrogenesis-associated pathways and ECM interactions. In conclusion, our data provide new insights on the potential mechanism of action of MSC-EVs as a treatment option for early-stage OA, including transcriptomic analysis of MSC-EV-treated OA, which may pave the way for more targeted novel therapeutics.

The potential role of stem cells-derived extracellular vesicles in the treatment of musculoskeletal system diseases

The therapeutic potential of stem cells-derived extracellular vesicles (EVs) has shown a great progress in the regenerative medicine. EVs are rich in a variety of bioactive substances, which are important carriers of signal transmission and interactions between cells, and they play an important role in the processes of tissue repair and regeneration. Several studies have shown that stem cells-derived EVs regulate immunity, promote cell proliferation and differentiation, enhance bone and vascular regeneration, and play an increasingly important role in musculoskeletal system. This review aimed to describe the biological characteristics of stem cells-derived EVs and discuss their potential role in the therapy of musculoskeletal system diseases.

In Situ Sodium Chloride Cross-Linked Fish Skin Collagen Scaffolds for Functional Hemostasis Materials

Current fish collagen hemostasis for wound healing products is commonly obtained by electrospinning or artificial cross-linking fish collagen fibers which lacks mechanical properties, and biofunctions. Here, a new bio-active fish skin scaffold (FSS) is shown using in situ cross-linked scaleless freshwater fish skin adding adipose-derived stem cells (ASCs)-produced exosomes for hemostasis and wound healing. The structure, pore size, and the thickness of FSS is studied by swelling test, Fourier-transform infrared (FT-IR) spectra, scanning electron microscope (SEM) images, and histological analysis. The biofunctions of the FSS are also tested in vitro and in vivo. FSS keeps two functional layers: The dermis layer collagen forms a sponge like structure after swelling and in situ cross-linking treatments. The pore size of the FSS is ≈152 ± 23.54 µm, which is suitable for cells growing, angiogenesis and ASCs exosomes accelerate wound healing. The fat-rich epidermis layer can keep the wound moisty and clean before completely healed. In vitro and in vivo experimental results indicate that FSS+Exosomes enhances rat skin cavity wound healing. In situ sodium chloride cross-linked FSS+Exosomes provides a new strategy as functional hemostatic dressing scaffold for wound healing.

Effects of periodontal ligament stem cell-derived exosomes on osteoblastic proliferation, migration, differentiation, apoptosis, and signaling pathways

OBJECTIVE

Periodontitis is characterized by alveolar bone injury and absorption, with high incidence and poor treatment effect. Proliferation, migration, differentiation and apoptosis of osteoblasts are identified as key factors during the regeneration of alveolar bone tissue processes. Periodontal ligament stem cells (PDLSCs) have been proved to be a possible candidate for the treatment of periodontitis due to its multiple advantages, such as increasing the regenerative capacity of bone tissue. However, the effect of exosomes derived from PDLSCs (PDLSC-Exo) on osteoblasts remains to be further studied.

METHODS AND MATERIALS

In this work, cell proliferation, migration, osteogenic differentiation, and H2 O2 -induced apoptosis were detected after cells were exposed to PDLSC-Exo by CCK-8, scratch wound assay, alizarin red S and alkaline phosphatase staining, real-time PCR, flow cytometry, tunel assay, and so on. Moreover, the activation of PI3K/AKT and MEK/ERK signaling pathways was evaluated by western blotting.

RESULTS

We found that PDLSC-Exo are capable of promoting hFOB1.19 cell proliferation, migration and osteogenic differentiation, inhibiting H2 O2 -induced apoptosis, and activating the PI3K/AKT and MEK/ERK signaling pathways.

CONCLUSION

These results suggest that PDLSC-Exo may be a promising therapeutic for osteoblastic damage.

Modern techniques in addressing facial acne scars: A thorough analysis

BACKGROUND

Facial acne scars are a prevalent concern, leading to the development of various treatment modalities.

OBJECTIVES

This review aims to explore the latest advancements in the treatment of facial acne scars, focusing on both surgical and non-surgical methods.

METHODS

The non-surgical treatments reviewed include topical medications (such as retinoids and alpha hydroxy acids) and non-invasive procedures (like microdermabrasion and chemical peels). Surgical options discussed are punch excision, subcision, and fractional laser treatments.

RESULTS

Combination therapy, integrating both surgical and non-surgical approaches, is frequently utilized to achieve optimal results in scar improvement.

CONCLUSION

Recent advancements in the treatment of facial acne scars provide promising options for individuals seeking improvement. However, these treatments have associated risks and potential adverse effects, highlighting the importance of consulting a dermatologist before beginning any treatment regimen.

Protective effect of oral stem cells extracellular vesicles on cardiomyocytes in hypoxia-reperfusion

Hypoxia signaling plays an important role in physiological and pathological conditions. Hypoxia in the heart tissue can produce different consequences depending on the duration of exposure to the hypoxic state. While acute hypoxic exposure leads to a reversible acclimatization in heart tissue with normal systemic oxygen supply, chronic hypoxia exacerbates cardiac dysfunction, leads to a destruction of the tissue. Extracellular vesicles (EVs) are small membrane vesicles that act as mediators of intercellular communication. EVs are secreted by different cell types and those produced by oral cavity-derived mesenchymal stem cells (MSCs), including human gingival MSCs (hGMSCs), have pro-angiogenic and anti-inflammatory effects and showed therapeutic role in tissue regeneration. The aim of the present work was to evaluate the potential protective and regenerative role of EVs produced by hGMSCs, in an in vitro model of hypoxia-conditioned HL-1 cardiomyocytes through the expression analysis of following inflammatory, oxidative stress, angiogenesis, cell survival and apoptotic markers: HIF-1α, P300, NFkB, CCL2, IL1B, IL6, NRF2, CASP-3, BAX and VEGF. Results showed that hGMSCs-derived EVs exerted protection HL-1 cardiomyocytes exposed to both pre and post hypoxic conditions. Moreover, modulation of CASP3 and BAX expression demonstrated that EVs reduced the apoptosis. The analysis of microRNAs in EVs derived from hGMSCs was performed to assess the epigenetic regulation of the presented markers. The following microRNAs: hsa-miR-138-5p, hsa-miR-17-5p, hsa-miR-18a-5p, hsa-miR-21-5p, hsa-miR-324-5p, hsa-miR-133a-3p, hsa-miR-150-5p, hsa-miR-199a-5p, hsa-miR-128-3p and hsa-miR-221-3p can directly or indirectly target the studied genes by determining their modulation obtained in our study. The data from this study suggested that EVs obtained from hGMSCs may be considered for the cell free treatment option in hypoxia-driven cardiac tissue dysfunction.

Extracellular Vesicles in Domestic Animals: Cellular Communication in Health and Disease

Apoptotic and healthy cells of domestic animals release membrane-enclosed particles from their plasma membrane. These special structures, called extracellular vesicles, play an important role in intercellular communication. In the past, it was believed that their function was mainly to dispose unwanted cell contents and to help maintain cell homeostasis. However, we now know that they have important roles in health and disease and have diagnostic value as well as great potential for therapy in veterinary medicine. Extracellular vesicles facilitate cellular exchanges by delivering functional cargo molecules to nearby or distant tissues. They are produced by various cell types and are found in all body fluids. Their cargo reflects the state of the releasing parent cell, and despite their small size, this cargo is extraordinarily complex. Numerous different types of molecules contained in vesicles make them an extremely promising tool in the field of regenerative veterinary medicine. To further increase research interest and discover their full potential, some of the basic biological mechanisms behind their function need to be better understood. Only then will we be able to maximize the clinical relevance for targeted diagnostic and therapeutic purposes in various domestic animal species.

Mesenchymal stem cell-derived exosomes for managing graft-versus-host disease: An updated view

Graft-versus-host disease (GvHD) is the most common complication after stem cell transplantation, and also it is one of the primary limiting factors for the use of hematopoietic stem cell transplantation (HSCT) in the treatment of hematologic cancers. GvHD, a systemic inflammatory disease, is caused by donor T cells recognizing the recipient's foreign antigens. In addition, an immune dysregulation, caused by autoreactive immune cells, complicates potent inflammatory process following HSCT. While there is no one approved treatment method for GvHD, corticosteroids are the most common first-line treatment. Exosomes are biological vesicles between 30 and 120 nm in diameter, which carry various biologically active molecules. They are known to play a key role in the paracrine effect of mesenchymal stem cells with therapeutic and tissue repair effects, including an immunosuppressive potential. Exosomes are unable to replicate themselves but because of their small size and fluid-like structure, they can pass through physiological barriers. Exosome are relatively easy to prepare and they can be quickly sterilized by a filtration process. Administration of exosomes, derived from mesenchymal stem cells, effectively reduced GvHD symptoms and significantly increased HSCT recipients' survival. Mesenchymal stem cell-derived exosome therapy reduced clinical symptoms of GvHD in patients after HSCT. Studies in patients with GvHD described that that mesenchymal stem cell-derived exosomes inhibited the release of IFN-γ and TNF-α by activated natural killer (NK cells), thereby reducing the lethal function of NK cells and inflammatory responses. Current review provides a comprehensive overview about the use of mesenchymal stem cells and their derived exosomes for the treatment of GvHD.

Exosomes loaded with chondrogenic stimuli agents combined with 3D bioprinting hydrogel in the treatment of osteoarthritis and cartilage degeneration

Osteoarthritis (OA) is a challenging joint inflammatory disease that often leads to disability. Immunoregulatory Exosomes (Exos) have shown promise in OA and cartilage degeneration treatment. Engineering Exos to deliver therapeutic agents like Kartogenin (KGN) has displayed potential for restoring cartilage regeneration. However, challenges include the uneven distribution of Exos at the injury site and the release of Exos cargo out of chondrocytes. Hydrogel-loaded uMSC-Exo has demonstrated significant therapeutic effects in wound healing and tissue regeneration. Recently, a new version of three-dimensional (3D) bioprinting of hydrogel significantly restored cartilage regeneration in OA joints. Combining immune regulatory Exos with 3D bioprinting hydrogel (3D-BPH-Exos) holds the potential for immunomodulating cartilage tissue and treatment of OA. It can reduce intracellular inflammasome formation and the release of inflammatory agents like IL-1β, TNF-α, and INF-γ, while also preventing chondrocyte apoptosis by restoring mitochondrial functions and enhancing chondrogenesis in synovial MSCs, osteoprogenitor cells, and osteoclasts. Loading Exos with chondrogenic stimuli agents in the 3D-BPH-Exos approach may offer a faster and safer strategy for cartilage repair while better inhibiting joint inflammation than high doses of anti-inflammatory drugs and cell-based therapies. This review provides a comprehensive overview of hydrogel bioprinting and exosome-based therapy in OA. It emphasizes the potential of 3D-BPH-Exos loaded with chondrogenic stimuli agents for OA treatment, serving as a basis for further research.

Regeneration and anti-inflammatory effects of stem cells and their extracellular vesicles in gynecological diseases

There are many gynecological diseases, among which breast cancer (BC), cervical cancer (CC), endometriosis (EMs), and polycystic ovary syndrome (PCOS) are common and difficult to cure. Stem cells (SCs) are a focus of regenerative medicine. They are commonly used to treat organ damage and difficult diseases because of their potential for self-renewal and multidirectional differentiation. SCs are also commonly used for difficult-to-treat gynecological diseases because of their strong directional differentiation ability with unlimited possibilities, their tendency to adhere to the diseased tissue site, and their use as carriers for drug delivery. SCs can produce exosomes in a paracrine manner. Exosomes can be produced in large quantities and have the advantage of easy storage. Their safety and efficacy are superior to those of SCs, which have considerable potential in gynecological treatment, such as inhibiting endometrial senescence, promoting vascular reconstruction, and improving anti-inflammatory and immune functions. In this paper, we review the mechanisms of the regenerative and anti-inflammatory capacity of SCs and exosomes in incurable gynecological diseases and the current progress in their application in genetic engineering to provide a foundation for further research.

Extracellular Vesicles Derived from Auricular Chondrocytes Facilitate Cartilage Differentiation of Adipose-Derived Mesenchymal Stem Cells

PURPOSE

Adipose-derived mesenchymal stem cell (ADSC)-based therapies have been utilized for cartilage regeneration because of their multi-lineage differentiation ability. However, commonly used cartilage inducers such as the transforming growth factor beta-3 (TGF-β3) may be prone to cartilage dedifferentiation and hypertrophy. The directional differentiation of elastic cartilage is limited nowadays. Extracellular vesicles (EVs) have been reported to influence the specific differentiation of mesenchymal stem cells (MSCs) by reflecting the composition of the parental cells. However, the role of auricular chondrogenic-derived EVs (AC-EVs) in elastic chondrogenic differentiation of ADSCs has not yet been reported.

RESULTS

AC-EVs isolated from the external ears of swine exhibited a positive effect on cell proliferation and migration. Furthermore, AC-EVs efficiently promoted chondrogenic differentiation of ADSCs in pellet culture, as shown by the elevated levels of COL2A1, ACAN, and SOX-9 expression. Moreover, there was a significantly higher expression of elastin and a lower expression of the fibrotic marker COL1A1 in comparison with that achieved with TGF-β3. The staining results demonstrated that AC-EVs promoted the deposition of cartilage-specific matrix, which is in good concordance with the real-time polymerase chain reaction (RT-PCR) results.

CONCLUSIONS

Auricular chondrogenic-derived EVs are a crucial component in elastic chondrogenic differentiation and other biological behaviors of ADSCs, which may be a useful ingredient for cartilage tissue engineering and external ear reconstruction.

NO LEVEL ASSIGNED

This journal requires that authors 42 assign a level of evidence to each submission to which 43 Evidence-Based Medicine rankings are applicable. This 44 excludes Review Articles, Book Reviews, and manuscripts 45 that concern Basic Science, Animal Studies, Cadaver 46 Studies, and Experimental Studies. For a full description of 47 these Evidence-Based Medicine ratings, please refer to the 48 Table oôf Contents or the online Instructions to Authors 49 www.springer.com/00266 .

Mechanisms and Optimization Strategies of Paracrine Exosomes from Mesenchymal Stem Cells in Ischemic Heart Disease

The morbidity and mortality of myocardial infarction (MI) are increasing worldwide. Mesenchymal stem cells (MSCs) are multipotent stem cells with self-renewal and differentiation capabilities that are essential in tissue healing and regenerative medicine. However, the low implantation and survival rates of transplanted cells hinder the widespread clinical use of stem cells. Exosomes are naturally occurring nanovesicles that are secreted by cells and promote the repair of cardiac function by transporting noncoding RNA and protein. In recent years, MSC-derived exosomes have been promising cell-free treatment tools for improving cardiac function and reversing cardiac remodeling. This review describes the biological properties and therapeutic potential of exosomes and summarizes some engineering approaches for exosomes optimization to enhance the targeting and therapeutic efficacy of exosomes in MI.

MicroRNA-122-5p alleviates endometrial fibrosis via inhibiting the TGF-β/SMAD pathway in Asherman's syndrome

RESEARCH QUESTION

What is the effect of miR-122 on the progression and recovery of fibrosis in Asherman's syndrome?

DESIGN

Endometrial tissue was collected from 21 patients, 11 with intrauterine adhesion (IUA) and 10 without IUA. Quantitative real-time polymerase chain reaction, immunofluorescence and Western blot were applied to observe the expression of mRNAs/miRNAs and protein, respectively. The endometrial physical injury was carried out in C57BL/6 mice to create an endometrial fibrosis model, with intrauterine injection of adenovirus to compare the antifibrosis and repair function of miR-122 on endometrium. The morphology of the uterus was observed using haematoxylin and eosin staining, and fibrosis markers were detected by immunohistochemistry.

RESULTS

miR-122 expression was reduced in patients with IUAs, accompanied by fibrosis. MiR-122 overexpression reduced the degree of fibrosis in endometrial stromal cells. Further molecular analyses demonstrated that miR-122 inhibited fibrosis through the TGF-β/SMAD pathway by directly targeting the 3' untranslated region of SMAD family member 3, suppressing its expression. Notably, miR-122 promoted endometrial regeneration and recovery of pregnancy capacity in a mouse endometrial injury model.

CONCLUSIONS

miR-122 is a critical regulator for repair of endometrial fibrosis and provided new insight for the clinical treatment of intrauterine adhesions.

Advances in Mesenchymal stem cells regulating macrophage polarization and treatment of sepsis-induced liver injury

Sepsis is a syndrome of dysregulated host response caused by infection, which leads to life-threatening organ dysfunction. It is a familiar reason of death in critically ill patients. Liver injury frequently occurs in septic patients, yet the development of targeted and effective treatment strategies remains a pressing challenge. Macrophages are essential parts of immunity system. M1 macrophages drive inflammation, whereas M2 macrophages possess anti-inflammatory properties and contribute to tissue repair processes. Mesenchymal stem cells (MSCs), known for their remarkable attributes including homing capabilities, immunomodulation, anti-inflammatory effects, and tissue regeneration potential, hold promise in enhancing the prognosis of sepsis-induced liver injury by harmonizing the delicate balance of M1/M2 macrophage polarization. This review discusses the mechanisms by which MSCs regulate macrophage polarization, alongside the signaling pathways involved, providing an idea for innovative directions in the treatment of sepsis-induced liver injury.

Characterization of Canine Gingival-Derived Mesenchymal Stem Cells and Their Exosomes

Mesenchymal stem cells (MSCs) can be isolated from numerous tissues and have the potential for self-renewal and multidirectional differentiation. Evidence is accumulating which suggests that MSCs are also present in the gingival tissue. This study aimed to evaluate the feasibility of collecting, purifying, and amplifying gingival-derived MSCs (GMSCs) from canine gingiva and to obtain GMSC-derived exosomes (GMSC-exo). GMSCs were isolated and cultured; furthermore, cellular immunofluorescence demonstrated that GMSCs possess characteristic MSC markers, and in vitro differentiation was induced, indicating that GMSCs can differentiate into multiple lineages. GMSC-exo was successfully extracted from GMSCs supernatant and found that they exhibit the typical characteristics of exosomes as analyzed by transmission electron microscopy, nanoflow analysis, and western blotting. GMSC-exo promoted the proliferation and migration of Madin-Darby canine kidney cells. It was concluded that canine gingiva is a good source of MSCs. Additionally, GMSC-exo is a potentially promising cell-free therapeutic tool for the treatment of canine gingival diseases.

Host and Pathogen-Directed Therapies against Microbial Infections Using Exosome- and Antimicrobial Peptide-derived Stem Cells with a Special look at Pulmonary Infections and Sepsis

Microbial diseases are a great threat to global health and cause considerable mortality and extensive economic losses each year. The medications for treating this group of diseases (antibiotics, antiviral, antifungal drugs, etc.) directly attack the pathogenic agents by recognizing the target molecules. However, it is necessary to note that excessive use of any of these drugs can lead to an increase in microbial resistance and infectious diseases. New therapeutic methods have been studied recently using emerging drugs such as mesenchymal stem cell-derived exosomes (MSC-Exos) and antimicrobial peptides (AMPs), which act based on two completely different strategies against pathogens including Host-Directed Therapy (HDT) and Pathogen-Directed Therapy (PDT), respectively. In the PDT approach, AMPs interact directly with pathogens to interrupt their intrusion, survival, and proliferation. These drugs interact directly with the cell membrane or intracellular components of pathogens and cause the death of pathogens or inhibit their replication. The mechanism of action of MSC-Exos in HDT is based on immunomodulation and regulation, promotion of tissue regeneration, and reduced host toxicity. This review studies the potential of mesenchymal stem cell-derived exosomes/ATPs therapeutic properties against microbial infectious diseases especially pulmonary infections and sepsis.

Antler stem cell exosomes alleviate pulmonary fibrosis via inhibiting recruitment of monocyte macrophage, rather than polarization of M2 macrophages in mice

Pulmonary fibrosis (PF), a chronic interstitial lung disease, is characterized by over-abundant deposition of extracellular matrix consisting mainly of collagen I. In previous studies, we demonstrated that deer antler stem cells (AnSCs), a novel type of adult stem cell, are capable of significantly down-regulating collagen formation in different organs and tissues and speculated that they could effectively treat PF via reducing collagen deposition in the lung tissue. In the present study, we found that administration of AnSCs improved the survival rate of PF mice and reduced lung fibrosis, collagen deposition and myofibroblast differentiation. The effects of AnSC treatment were significantly better than the positive control (adipose-derived stem cells). Interestingly, AnSC-Exos were almost equally effective as AnSCs in treating PF, suggesting that the effects of AnSCs on reduction of PF may be mainly through a paracrine mechanism. Further, AnSC-Exos reduced the number of M2 macrophages, a type of macrophage that secrets pro-fibrotic factors to accelerate fibrotic progression, in the lung tissues. In vitro experiments showed that the effects of AnSC-Exos on macrophage modulation were likely achieved via inhibition of the recruitment of circulating monocyte-derived macrophages (reducing the number of macrophages), rather than via inhibition of M2 polarization of macrophages. Inhibition of macrophage recruitment by AnSCs may be achieved indirectly via inhibiting CCL7 expression in fibroblasts; both let-7b and let-7a were highly enriched in AnSC-Exos and may play a critical role in the inhibition of CCL7 expression of fibroblasts. Collectively, the use of antler stem cells or their exosomes opens up a novel strategy for PF treatment in the clinical setting.

Mesenchymal Stem Cell-Derived Exosomes: A Novel Approach to Diabetes-Associated Cognitive Impairment

The progression of diabetes frequently results in a myriad of neurological disorders, including ischemic stroke, depression, blood-brain barrier impairment, and cognitive dysfunction. Notably, diabetes-associated cognitive impairment, a prevalent comorbidity during the course of diabetes, progressively affects patients' cognitive abilities and may reciprocally influence diabetes management, thereby severely impacting patients' quality of life. Extracellular vesicles, particularly nanoscale exosomes, have garnered considerable attention in recent years. These exosomes carry and transfer various functional molecules, such as proteins, lipids, and diverse non-coding RNAs, serving as novel regulators and communicators in intercellular interactions. Of particular interest, mesenchymal stem cell-derived exosomes (MSC-Exos) have been reported to traverse the blood-brain barrier and ameliorate intracerebral pathologies. This review elucidates the role of MSC-Exos in diabetes-related cognitive impairment, with a focus on their applications as biomarkers, modulation of neuronal regeneration and synaptic plasticity, anti-inflammatory properties, antioxidative effects, and their involvement in regulating the functionality of β-amyloid proteins during the course of cognitive impairment. The immense therapeutic potential of MSC-Exos in the treatment of diabetes-induced cognitive dysfunction is emphasized.

Suprachoroidal spheroidal mesenchymal stem cell implantation in retinitis pigmentosa: clinical results of 6 months follow-up

PURPOSE

This prospective clinical case series aimed to evaluate the effect of suprachoroidal implantation of mesenchymal stem cells (MSCs) in the form of spheroids as a stem cell therapy for retinitis pigmentosa (RP) patients with relatively good visual acuity.

METHODS

Fifteen eyes of 15 patients with RP who received suprachoroidal implantation of MSCs in the form of spheroids were included. Best-corrected visual acuity (BCVA), 10-2 and 30-2 visual field examination and multifocal electroretinography (mfERG) recordings were recorded at baseline, postoperative 1st, 3rd and 6th months during follow-up.

RESULTS

Baseline median BCVA of RP patients was 1.30 (1.00-2.00) logMAR. BCVA has improved to 1.00 (0.50-1.30), 0.80 (0.40-1.30) and 0.80 (0.40-1.30) at the postoperative 1st, 3rd and 6th months, respectively. The improvements from baseline to the 3rd and 6th months were statistically significant (p = 0.03 and p < 0.001, respectively). In the 30-2 VF test, median MD was significantly improved at the 6th month compared to baseline (p = 0.030). In the 10-2 VF test, the median MD value was significantly different at the 6th month compared to the baseline (p = 0.043). The PSD value of the 10-2 VF test was significantly different at the 6th month compared to the 3rd month (p = 0.043). The amplitudes of P1 waves in < 2°, 5°-10° and 10°-15° rings improved significantly at the postoperative 6th month (p = 0.014, p = 0.018 and p = 0.017, respectively). There was also a statistically significant improvement in implicit times of P1 waves in 10°-15° ring at the postoperative 6th month (p = 0.004).

CONCLUSION

Suprachoroidal implantation of MSCs in the form of spheroids as a stem cell therapy for RP patients with relatively good visual acuity has an improving effect on BCVA, VF and mfERG recordings during the 6-month follow-up period. Spheroidal MSCs with enhanced effects may be more successful in preventing apoptosis and improving retinal tissue healing in RP patients.

Small Extracellular Vesicles Maintain Homeostasis of Senescent Mesenchymal Stem Cells at Least Through Excreting Harmful Lipids

Mesenchymal stem cells (MSCs) play an essential role in multiple physiological processes in vivo and a promising cell-based therapy for various diseases. Nonetheless, MSCs suffer from senescence with expansion culture, leading to a limitation for their clinical application. Recently, it was reported that small extracellular vesicles (sEVs) are involved in regulation of senescence in tumor cells and fibroblasts. However, the biological roles of sEVs in senescent MSCs (Sen MSCs) are poorly understood. In this study, we established a replicative senescence model of MSCs by successive passages and compared the phenotypic changes between presenescent MSCs (Pre-Sen MSCs) and Sen MSCs and found that Sen MSCs exhibited a diminished adipogenic and osteogenic differentiation potential and elevated senescence-associated secretory phenotype levels. In addition, we found that sEV secretion was increased in Sen MSCs, and inhibition of sEV secretion led to apoptosis, DNA damage, and decreased cell viability, suggesting that increased sEV secretion plays an important role in maintaining Sen MSC homeostasis. To further investigate the molecular mechanisms, metabolomic profiling of Pre-Sen MSC-derived sEVs (Pre-Sen-sEVs) and Sen MSC-derived sEVs (Sen-sEVs) was performed. The results showed that lipid metabolites were significantly increased in Sen-sEVs and these significantly upregulated lipid metabolites were shown to be toxic for inducing cellular senescence and apoptosis in previous studies. Kyoto Encyclopedia of Genes and Genomes analysis revealed enrichment of differential metabolites between Pre-Sen-sEVs and Sen-sEVs mainly in 25 signaling pathways, of which 21 metabolic pathways have been shown to be closely associated with senescence. Taken together, our findings suggested that increased sEV secretion maintains Sen MSC homeostasis, at least in part, by excreting harmful lipids, thus providing new insights into the regulation of senescence by sEVs.

Bone marrow mesenchymal stem cells' osteogenic potential: superiority or non-superiority to other sources of mesenchymal stem cells?

Skeletal problems are an increasing issue due to the increase in the global aging population. Different statistics reports show that today, the global population is aging that results in skeletal problems, increased health system costs, and even higher mortality associated with skeletal problems. Common treatments such as surgery and bone grafts are not always effective and in some cases, they can even cause secondary problems such as infections or improper repair. Cell therapy is a method that can be utilized along with common treatments independently. Mesenchymal stem cells (MSCs) are a very important and efficient source in terms of different diseases, especially bone problems. These cells are present in different tissues such as bone marrow, adipose tissue, umbilical cord, placenta, dental pulp, peripheral blood, amniotic fluid and others. Among the types of MSCs, bone marrow mesenchymal stem cells (BMMSCs) are the most widely used source of these cells, which have appeared to be very effective and promising in terms of skeletal diseases, especially compared to the other sources of MSCs. This study focuses on the specific potential and content of BMMSCs from which the specific capacity of these cells originates, and compares their osteogenic potential with other types of MSCs, and also the future directions in the application of BMMSCs as a source for cell therapy.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Microvesicles Could Induce Apoptosis and Autophagy in Acute Myeloid Leukemia

Background

Microvesicles (MV) have been identified as candidate biomarkers for treating acute myeloid leukemia (AML). This study investigated the effects of human umbilical cord-derived mesenchymal stem cell (hUCMSC)-derived MVs on apoptosis and autophagy in the KG-1 leukemic cell line.

Methods

The hUCMSCs were cultured and characterized by flow cytometry. MVs were isolated by ultracentrifugation, and the concentration was determined using the Bradford method. The characteristics of MVs were confirmed using transmission electron microscopy, flow cytometry, and dynamic light scattering methods. KG-1 cells were treated with the desired concentrations of MVs for 24 h. The apoptosis induction and reactive oxygen species production were evaluated using flow cytometry. RT-PCR was performed to evaluate apoptosis- and autophagy-related genes expression.

Results

Following tretment of KG-1 cells with 25, 50, and 100 μg/ml concentrations of MVs, the apoptosis rates were 47.85%, 47.15%, and 51.35% (p < 0.0001), and the autophagy-induced ROS levels were 73.9% (p < 0.0002), 84.8% (p < 0.0001), and 85.4% (p < 0.0001), respectively. BAX and ATG7 gene expression increased significantly at all concentrations compared to the control, and this level was higher at 50 μg/ml than that of the other concentrations. In addition, LC3 and Beclin 1 expression increased significantly in a concentration-dependen manner. Conversely, BCL2 expression decreased compared to the control.

Conclusion

Our findings indicate that hUCMSC-MVs could induce cell death pathways of autophagy and apoptosis in the KG-1 cell lines and exert potent antiproliferative and proapoptotic effects on KG-1 cells in vitro. Therefore, hUCMSC-MVs may be a potential approach for cancer therapy as a novel cell-to-cell communication strategy.

Extracellular Vesicles Derived from Mesenchymal Stem Cells as Cell-Free Therapy for Intrauterine Adhesion

Intrauterine adhesion (IUA) can occur after trauma to the basal layer of the endometrium, contributing to severe complications in females, such as infertility and amenorrhea. To date, the proposed therapeutic strategies are targeted to relieve IUA, such as hysteroscopic adhesiolysis, Foley catheter balloon, and hyaluronic acid injection have been applied in the clinic. However, these approaches showed limited effects in alleviating endometrial fibrosis and thin endometrium. Mesenchymal stem cells (MSCs) can offer the potential for endometrium regeneration owing to reduce inflammation and release growth factors. On this basis, MSCs have been proposed as promising methods to treat intrauterine adhesion. However, due to the drawbacks of cell therapy, the possible therapeutic use of extracellular vesicles released by stem cells is raising increasing interest. The paracrine effect, mediated by MSCs derived extracellular vehicles (MSC-EVs), has recently been suggested as a mechanism for their therapeutic properties. Here, we summarizes the main pathological mechanisms involved in intrauterine adhesion, the biogenesis and characteristics of extracellular vesicles, explaining how these vesicles could provide new opportunities for MSCs.

Nature vs. Manmade: Comparing Exosomes and Liposomes for Traumatic Brain Injury

Traumatic brain injury (TBI) of all severities is a significant public health burden, causing a range of effects that can lead to death or a diminished quality of life. Liposomes and mesenchymal stem cell-derived exosomes are two drug delivery agents with potential to be leveraged in the treatment of TBI by increasing the efficacy of drug therapies as well as having additional therapeutic effects. They exhibit several physical similarities, but key differences affect their performances as nanocarriers. Liposomes can be produced commercially at scale, and liposomes achieve higher encapsulation efficiency. Meanwhile, the intrinsic cargo and targeting moieties of exosomes, which liposomes lack, give exosomes a greater ability to facilitate neural regeneration, and exosomes do not trigger the infusion reactions that liposomes can. However, there are concerns about both exosomes and liposomes regarding interactions with tumors. The same routes of administration can be used for both exosomes and liposomes, resulting in somewhat different distribution throughout the body. While the effect of the nanocarrier type on accumulation in the brain is not concrete, targeting leads to increased accumulation of both exosomes and liposomes in the brain, upon which on-demand release can be used for both drug deliverers. Although neither have been applied to TBI in humans, preclinical trials have shown their immense potential, as have clinical trials pertaining to other brain injuries and conditions. While questions remain, research thus far shows that the various differences make exosomes a better choice of nanocarrier for TBI.

Neural stem cell-derived exosomes and regeneration: cell-free therapeutic strategies for traumatic brain injury

Regenerative repair of the brain after traumatic brain injury (TBI) remains an extensive clinical challenge, inspiring intensified interest in therapeutic approaches to explore superior repair strategies. Exosome therapy is another research hotspot following stem cell alternative therapy. Prior research verified that exosomes produced by neural stem cells can participate in the physiological and pathological changes associated with TBI and have potential neuroregulatory and repair functions. In comparison with their parental stem cells, exosomes have superior stability and immune tolerance and lower tumorigenic risk. In addition, they can readily penetrate the blood‒brain barrier, which makes their treatment efficiency superior to that of transplanted stem cells. Exosomes secreted by neural stem cells present a promising strategy for the development of novel regenerative therapies. Their tissue regeneration and immunomodulatory potential have made them encouraging candidates for TBI repair. The present review addresses the challenges, applications and potential mechanisms of neural stem cell exosomes in regenerating damaged brains.

Stem Cell Therapy in Spinal Cord Injury-Induced Neurogenic Lower Urinary Tract Dysfunction

Spinal cord injury (SCI) is a devastating condition that enormously affects an individual's health and quality of life. Neurogenic lower urinary tract dysfunction (NLUTD) is one of the most important sequelae induced by SCI, causing complications including urinary tract infection, renal function deterioration, urinary incontinence, and voiding dysfunction. Current therapeutic methods for SCI-induced NLUTD mainly target on the urinary bladder, but the outcomes are still far from satisfactory. Stem cell therapy has gained increasing attention for years for its ability to rescue the injured spinal cord directly. Stem cell differentiation and their paracrine effects, including exosomes, are the proposed mechanisms to enhance the recovery from SCI. Several animal studies have demonstrated improvement in bladder function using mesenchymal stem cells (MSCs) and neural stem cells (NSCs). Human clinical trials also provide promising results in urodynamic parameters after MSC therapy. However, there is still uncertainty about the ideal treatment window and application protocol for stem cell therapy. Besides, data on the therapeutic effects regarding NSCs and stem cell-derived exosomes in SCI-related NLUTD are scarce. Therefore, there is a pressing need for further well-designed human clinical trials to translate the stem cell therapy into a formal therapeutic option for SCI-induced NLUTD.