Role of extracellular vesicles from adipose tissue- and bone marrow-mesenchymal stromal cells in endothelial proliferation and chondrogenesis

EnduroBone: A 3D printed bioreactor for extended bone tissue culture

Studies of the effects of external stimuli on bone tissue, disease transmission mechanisms, and potential medication discoveries benefit from long-term tissue viability ex vivo. By simulating the in-vivo environment, bioreactors are essential for studying bone cellular activity throughout biological processes. We present the development of an automated 3D-printed bioreactor EnduroBone designed to sustain the ex-vivo viability of 10 mm diameter cancellous bone cores for an extended period. The device is supplied with two critical parameters for maintaining bone tissue viability: closed-loop continuous flow perfusion of 1 mL/min for nutrient diffusion and waste removal and direct mechanical stimulation with cyclic compression at 13.2 RPM (revolutions per minute) to promote cell viability which can lead to improved tissue stability during ex vivo culturing. The bioreactor addresses several limitations of existing systems and provides a versatile open-source platform for bone cancer research, orthopedic device testing, and other related applications. To validate the bioreactor, fresh swine samples were cultured ex-vivo, and their cell viability was determined to be maintained for up to 28 days. Periodic cell viability assessment through live/dead cell staining and confocal imaging at the start (0 days) and at several time points throughout the culture period (7, 14, 21, and 28 days) was used to demonstrate EnduroBone effectiveness in sustaining bone cell health for the extended period tested.

Mesenchymal stem cell-derived exosomes as a promising cell-free therapy for knee osteoarthritis

Osteoarthritis (OA), as a degenerative disease, leads to high socioeconomic burdens and disability rates. The knee joint is typically the most affected and is characterized by progressive destruction of articular cartilage, subchondral bone remodeling, osteophyte formation and synovial inflammation. The current management of OA mainly focuses on symptomatic relief and does not help to slow down the advancement of disease. Recently, mesenchymal stem cells (MSCs) and their exosomes have garnered significant attention in regenerative therapy and tissue engineering areas. Preclinical studies have demonstrated that MSC-derived exosomes (MSC-Exos), as bioactive factor carriers, have promising results in cell-free therapy of OA. This study reviewed the application of various MSC-Exos for the OA treatment, along with exploring the potential underlying mechanisms. Moreover, current strategies and future perspectives for the utilization of engineered MSC-Exos, alongside their associated challenges, were also discussed.

Safety and Tolerability of Intra-Articular Injection of Adipose-Derived Mesenchymal Stem Cells GXCPC1 in 11 Subjects With Knee Osteoarthritis: A Nonrandomized Pilot Study Without a Control Arm

The current study aimed to determine the safety profile of intra-articular-injected allogeneic adipose-derived mesenchymal stem cells (ADSCs) GXCPC1 in subjects with knee osteoarthritis (OA) and its preliminary efficacy outcome. The 3 + 3 phase I study was designed with two dose-escalation cohorts: low dose (6.7 × 106 GXCPC1, N = 5) and high dose (4 × 107 GXCPC1, N = 6). The primary endpoint was safety, which was evaluated by recording adverse events throughout the trial; the secondary endpoints included total, pain, stiffness, and function subscales of the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Visual Analogue Scale (VAS) for pain, and 12-Item Short Form (SF-12) health survey questionnaire. The GXCPC1 treatment was found to be safe after 1 year of follow-up with no treatment-related severe adverse events observed. When compared to baseline, subjects in both the low- and high-dose cohorts demonstrated improving trends in pain and knee function after receiving GXCPC1 treatment. Generally, the net change in pain (95% confidence interval (CI) = -7.773 to -2.561t at 12 weeks compared to baseline) and knee function (95% CI = -24.297 to -10.036t at 12 weeks compared to baseline) was better in subjects receiving high-dose GXCPC1. Although this study included a limited number of subjects without a placebo arm, it showed that the intra-articular injection of ADSCs was safe and well-tolerated in subjects with therapeutic alternatives to treat knee OA. However, a larger scale study with an appropriate control would be necessary for clinical efficacy in the following study.

Mesenchymal Stem Cell-Derived Exosomal microRNAs in Cardiac Regeneration

Mesenchymal stem cell (MSC)-based therapy is one of the most promising modalities for cardiac repair. Accumulated evidence suggests that the therapeutic value of MSCs is mainly attributable to exosomes. MSC-derived exosomes (MSC-Exos) replicate the beneficial effects of MSCs by regulating various cellular responses and signaling pathways implicated in cardiac regeneration and repair. miRNAs constitute an important fraction of exosome content and are key contributors to the biological function of MSC-Exo. MSC-Exo carrying specific miRNAs provides anti-apoptotic, anti-inflammatory, anti-fibrotic, and angiogenic effects within the infarcted heart. Studying exosomal miRNAs will provide an important insight into the molecular mechanisms of MSC-Exo in cardiac regeneration and repair. This significant information can help optimize cell-free treatment and overcome the challenges associated with MSC-Exo therapeutic application. In this review, we summarize the characteristics and the potential mechanisms of MSC-derived exosomal miRNAs in cardiac repair and regeneration.

Berberine-loaded MSC-derived sEVs encapsulated in injectable GelMA hydrogel for spinal cord injury repair

After spinal cord injury (SCI), local inflammatory response and fibrous scar formation severely hinder nerve regeneration. Berberine (Ber) has a powerful regulatory effect on the local microenvironment, but its limited solubility and permeability through the blood-brain barrier severely limit its systemic efficacy. Human umbilical cord mesenchymal stem cells (hUC-MSCs)-derived small extracellular vesicles (sEVs) are natural nanocarriers with high cargo loading capacity, and can cross the blood-brain barrier. Most importantly, sEVs can improve drug solubility and drug utilization. Therefore, they can overcome many defects of Ber application. This experiment aimed to design a Ber-carrying hUC-MSCs-derived sEVs and GelMA hydrogel. Ber was loaded into sEVs (sEVs-Ber) by ultrasonic co-incubation with a drug loading capacity (LC) of 15.07%. The unhindered release of up to 80% of sEVs-Ber from GelMA hydrogel was accomplished for up to 14 days. And they could be directly absorbed by local cells of injury, allowing for direct local delivery of the drug and enhancing its efficacy. The experimental results confirmed injecting GelMA-sEVs-Ber into spinal cord defects could exert anti-inflammatory effects by regulating the expression of inflammatory factors. It also demonstrated the anti-fibrotic effect of Ber in SCI for the first time. The modulatory effects of sEVs and Ber on the local microenvironment significantly promoted nerve regeneration and recovery of motor function in post-SCI rats. These results demonstrated that the GelMA-sEVs-Ber dual carrier system is a promising therapeutic strategy for SCI repair.

Extracellular vesicles in the treatment and prevention of osteoarthritis: can horses help us translate this therapy to humans?

Osteoarthritis (OA) is a common joint disease affecting humans and horses, resulting in significant morbidity, financial expense, and loss of athletic use. While the pathogenesis is incompletely understood, inflammation is considered crucial in the development and progression of the disease. Mesenchymal stromal cells (MSCs) have received increasing scientific attention for their anti-inflammatory, immunomodulatory, and pro-regenerative effects. However, there are concerns about their ability to become a commercially available therapeutic. Extracellular vesicles (EVs) are now recognized to play a crucial role in the therapeutic efficacy observed with MSCs and offer a potentially novel cell-free therapeutic that may negate many of the concerns with MSCs. There is evidence that EVs have profound anti-inflammatory, immunomodulatory, and pro-regenerative effects equal to or greater than the MSCs they are derived from in the treatment of OA. Most of these studies are in small animal models, limiting the translation of these results to humans. However, highly translational animal models are crucial for further understanding the efficacy of potential therapeutics and for close comparisons with humans. For this reason, the horse, which experiences the same gravitational impacts on joints similar to people, is a highly relevant large animal species for testing. The equine species has well-designed and validated OA models, and additionally, therapies can be further tested in naturally occurring OA to validate preclinical model testing. Therefore, the horse is a highly suitable model to increase our knowledge of the therapeutic potential of EVs.

BMSC-derived extracellular vesicles promoted osteogenesis via Axin2 inhibition by delivering MiR-16-5p

Osteoporosis (OP) is a systemic bone disease caused by an imbalance in osteogenesis and osteoclastic resorption. Extracellular vesicles (EVs)-encapsulated miRNAs from bone mesenchymal stem cells (BMSCs) have been reported to participate in osteogenesis. MiR-16-5p is one of the miRNAs that regulates osteogenic differentiation; however, studies have shown that its role in osteogenesis is controversial. Thus, this study aims to investigate the role of miR-16-5p from BMSC-derived extracellular vesicles (EVs) in osteogenic differentiation and uncover the underlying mechanisms. In this study, we used an ovariectomized (OVX) mouse model and an H₂O₂-treated BMSCs model to investigate the effects of BMSC-derived EVs and EV-encapsulated miR-16-5p on OP and the underlying mechanisms. Our results proved that the miR-16-5p level was significantly decreased in H₂O₂-treated BMSCs, bone tissues of OVX mice, and lumbar lamina tissues from osteoporotic women. EVs-encapsulated miR-16-5p from BMSCs could promote osteogenic differentiation. Moreover, the miR-16-5p mimics promoted osteogenic differentiation of H₂O₂-treated BMSCs, and the effects exerted by miR-16-5p were mediated by targeting Axin2, a scaffolding protein of GSK3β that negatively regulates the Wnt/β-catenin signaling pathway. This study provides evidence that EVs-encapsulated miR-16-5p from BMSCs could promote osteogenic differentiation by repressing Axin2.

Extracellular Vesicles as "Very Important Particles" (VIPs) in Aging

In recent decades, extracellular vesicles have been recognized as "very important particles" (VIPs) associated with aging and age-related disease. During the 1980s, researchers discovered that these vesicle particles released by cells were not debris but signaling molecules carrying cargoes that play key roles in physiological processes and physiopathological modulation. Following the International Society for Extracellular Vesicles (ISEV) recommendation, different vesicle particles (e.g., exosomes, microvesicles, oncosomes) have been named globally extracellular vesicles. These vesicles are essential to maintain body homeostasis owing to their essential and evolutionarily conserved role in cellular communication and interaction with different tissues. Furthermore, recent studies have shown the role of extracellular vesicles in aging and age-associated diseases. This review summarizes the advances in the study of extracellular vesicles, mainly focusing on recently refined methods for their isolation and characterization. In addition, the role of extracellular vesicles in cell signaling and maintenance of homeostasis, as well as their usefulness as new biomarkers and therapeutic agents in aging and age-associated diseases, has also been highlighted.

Conditioned Medium - Is it an Undervalued Lab Waste with the Potential for Osteoarthritis Management?

BACKGROUND

The approaches currently used in osteoarthritis (OA) are mainly short-term solutions with unsatisfactory outcomes. Cell-based therapies are still controversial (in terms of the sources of cells and the results) and require strict culture protocol, quality control, and may have side-effects. A distinct population of stromal cells has an interesting secretome composition that is underrated and commonly ends up as biological waste. Their unique properties could be used to improve the existing techniques due to protective and anti-ageing properties.

SCOPE OF REVIEW

In this review, we seek to outline the advantages of the use of conditioned media (CM) and exosomes, which render them superior to other cell-based methods, and to summarise current information on the composition of CM and their effect on chondrocytes.

MAJOR CONCLUSIONS

CM are obtainable from a variety of mesenchymal stromal cell (MSC) sources, such as adipose tissue, bone marrow and umbilical cord, which is significant to their composition. The components present in CMs include proteins, cytokines, growth factors, chemokines, lipids and ncRNA with a variety of functions. In most in vitro and in vivo studies CM from MSCs had a beneficial effect in enhance processes associated with chondrocyte OA pathomechanism.

GENERAL SIGNIFICANCE

This review summarises the information available in the literature on the function of components most commonly detected in MSC-conditioned media, as well as the effect of CM on OA chondrocytes in in vitro culture. It also highlights the need to standardise protocols for obtaining CM, and to conduct clinical trials to transfer the effects obtained in vitro to human subjects.

Cartilage 3D bioprinting for rhinoplasty using adipose-derived stem cells as seed cells: Review and recent advances

Nasal deformities due to various causes affect the aesthetics and use of the nose, in which case rhinoplasty is necessary. However, the lack of cartilage for grafting has been a major problem and tissue engineering seems to be a promising solution. 3D bioprinting has become one of the most advanced tissue engineering methods. To construct ideal cartilage, bio-ink, seed cells, growth factors and other methods to promote chondrogenesis should be considered and weighed carefully. With continuous progress in the field, bio-ink choices are becoming increasingly abundant, from a single hydrogel to a combination of hydrogels with various characteristics, and more 3D bioprinting methods are also emerging. Adipose-derived stem cells (ADSCs) have become one of the most popular seed cells in cartilage 3D bioprinting, owing to their abundance, excellent proliferative potential, minimal morbidity during harvest and lack of ethical considerations limitations. In addition, the co-culture of ADSCs and chondrocytes is commonly used to achieve better chondrogenesis. To promote chondrogenic differentiation of ADSCs and construct ideal highly bionic tissue-engineered cartilage, researchers have used a variety of methods, including adding appropriate growth factors, applying biomechanical stimuli and reducing oxygen tension. According to the process and sequence of cartilage 3D bioprinting, this review summarizes and discusses the selection of hydrogel and seed cells (centered on ADSCs), the design of printing, and methods for inducing the chondrogenesis of ADSCs.

Extracellular Vesicles as Carriers of Adipokines and Their Role in Obesity

Extracellular vesicles (EVs) have lately arisen as new metabolic players in energy homeostasis participating in intercellular communication at the local and distant levels. These nanosized lipid bilayer spheres, carrying bioactive molecular cargo, have somehow changed the paradigm of biomedical research not only as a non-classic cell secretion mechanism, but as a rich source of biomarkers and as useful drug-delivery vehicles. Although the research about the role of EVs on metabolism and its deregulation on obesity and associated pathologies lagged slightly behind other diseases, the knowledge about their function under normal and pathological homeostasis is rapidly increasing. In this review, we are focusing on the current research regarding adipose tissue shed extracellular vesicles including their characterization, size profile, and molecular cargo content comprising miRNAs and membrane and intra-vesicular proteins. Finally, we will focus on the functional aspects attributed to vesicles secreted not only by adipocytes, but also by other cells comprising adipose tissue, describing the evidence to date on the deleterious effects of extracellular vesicles released by obese adipose tissue both locally and at the distant level by interacting with other peripheral organs and even at the central level.

The therapeutic and commercial landscape of stem cell vesicles in regenerative dermatology

Extracellular vesicles (EVs) are lipid enveloped nanoparticles that are naturally produced by cells and function in the intercellular transfer of biological material such as proteins, RNAs and metabolites. They have been shown to act in an autocrine and paracrine manner to alter the functions of local and distant recipient cells, with a growing body of evidence highlighting their wide-ranging functions in regenerative processes such as stem cell maintenance, tissue repair and immune modulation. EVs offer several potential advantages over stem cell therapies such as improved safety profiles, scalability, and enhanced storage and quality control of the final product. In fact, many of the pro-regenerative outcomes of stem cell therapies have been attributed to the release of mesenchymal stem cell-derived EVs (MSC-EVs) and their potent effects on extracellular matrix turnover, local cell recruitment, proliferation and angiogenesis is now well described. These positive outcomes have led to clinical trials assessing the safety of MSC-EVs for applications in wound healing and the treatment of cutaneous ulcers, as well as the emergence of multiple commercial MSC-EV sources marketed for topical application in cosmetic medicine. However, regenerative EV therapeutics remain in their infancy and pertinent questions regarding product standardisation, potency and the regulatory landscape surrounding the development of these promising nano-therapeutics must be addressed to ensure safe and effective clinical adoption. In this article we provide an overview of the emerging landscape of MSC-EVs in regenerative dermatology and cosmetic science, highlighting the underlying biological mechanisms pertinent to their application and providing a perspective on current safety considerations, regulation and future directions in the field.

Tissue engineering in growth plate cartilage regeneration: Mechanisms to therapeutic strategies

The repair of growth plate injuries is a highly complex process that involves precise spatiotemporal regulation of multiple cell types. While significant progress has been made in understanding the pathological mechanisms underlying growth plate injuries, effectively regulating this process to regenerate the injured growth plate cartilage remains a challenge. Tissue engineering technology has emerged as a promising therapeutic approach for achieving tissue regeneration through the use of functional biological materials, seed cells and biological factors, and it is now widely applied to the regeneration of bone and cartilage. However, due to the unique structure and function of growth plate cartilage, distinct strategies are required for effective regeneration. Thus, this review provides an overview of current research on the application of tissue engineering to promote growth plate regeneration. It aims to elucidates the underlying mechanisms by which tissue engineering promotes growth plate regeneration and to provide novel insights and therapeutic strategies for future research on the regeneration of growth plate.

Therapeutic Potential of Extracellular Vesicles in Aging and Age-Related Diseases

Aging is associated with an alteration of intercellular communication. These changes in the extracellular environment contribute to the aging phenotype and have been linked to different aging-related diseases. Extracellular vesicles (EVs) are factors that mediate the transmission of signaling molecules between cells. In the aging field, these EVs have been shown to regulate important aging processes, such as oxidative stress or senescence, both in vivo and in vitro. EVs from healthy cells, particularly those coming from stem cells (SCs), have been described as potential effectors of the regenerative potential of SCs. Many studies with different animal models have shown promising results in the field of regenerative medicine. EVs are now viewed as a potential cell-free therapy for tissue damage and several diseases. Here we propose EVs as regulators of the aging process, with an important role in tissue regeneration and a raising therapy for age-related diseases.

Current applications of adipose-derived mesenchymal stem cells in bone repair and regeneration: A review of cell experiments, animal models, and clinical trials

In the field of orthopaedics, bone defects caused by severe trauma, infection, tumor resection, and skeletal abnormalities are very common. However, due to the lengthy and painful process of related surgery, people intend to shorten the recovery period and reduce the risk of rejection; as a result, more attention is being paid to bone regeneration with mesenchymal stromal cells, one of which is the adipose-derived mesenchymal stem cells (ASCs) from adipose tissue. After continuous subculture and cryopreservation, ASCs still have the potential for multidirectional differentiation. They can be implanted in the human body to promote bone repair after induction in vitro, solve the problems of scarce sources and large damage, and are expected to be used in the treatment of bone defects and non-union fractures. However, the diversity of its differentiation lineage and the lack of bone formation potential limit its current applications in bone disease. Here, we concluded the current applications of ASCs in bone repair, especially with the combination and use of physical and biological methods. ASCs alone have been proved to contribute to the repair of bone damage in vivo and in vitro. Attaching to bone scaffolds or adding bioactive molecules can enhance the formation of the bone matrix. Moreover, we further evaluated the efficiency of ASC-committed differentiation in the bone in conditions of cell experiments, animal models, and clinical trials. The results show that ASCs in combination with synthetic bone grafts and biomaterials may affect the regeneration, augmentation, and vascularization of bone defects on bone healing. The specific conclusion of different materials applied with ASCs may vary. It has been confirmed to benefit osteogenesis by regulating osteogenic signaling pathways and gene transduction. Exosomes secreted by ASCs also play an important role in osteogenesis. This review will illustrate the understanding of scientists and clinicians of the enormous promise of ASCs’ current applications and future development in bone repair and regeneration, and provide an incentive for superior employment of such strategies.

Regenerative and Anti-Inflammatory Potential of Regularly Fed, Starved Cells and Extracellular Vesicles In Vivo

Background: Mesenchymal stem/stromal cells (MSC) have been employed successfully in immunotherapy and regenerative medicine, but their therapeutic potential is reduced considerably by the ischemic environment that exists after transplantation. The assumption that preconditioning MSC to promote quiescence may result in increased survival and regenerative potential upon transplantation is gaining popularity. Methods: The purpose of this work was to evaluate the anti-inflammatory and regenerative effects of human bone marrow MSC (hBM-MSC) and their extracellular vesicles (EVs) grown and isolated in a serum-free medium, as compared to starved hBM-MSC (preconditioned) in streptozotocin-induced diabetic fractured male C57BL/6J mice. Results: Blood samples taken four hours and five days after injection revealed that cells, whether starved or not, generated similar plasma levels of inflammatory-related cytokines but lower levels than animals treated with EVs. Nonetheless, starved cells prompted the highest production of IL-17, IL-6, IL-13, eotaxin and keratinocyte-derived chemokines and induced an earlier soft callus formation and mineralization of the fracture site compared to EVs and regularly fed cells five days after administration. Conclusions: Preconditioning may be crucial for refining and defining new criteria for future MSC therapies. Additionally, the elucidation of mechanisms underpinning an MSC’s survival/adaptive processes may result in increased cell survival and enhanced therapeutic efficacy following transplantation.

An Overview of Current Research on Mesenchymal Stem Cell-Derived Extracellular Vesicles: A Bibliometric Analysis From 2009 to 2021

Background: Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are important mediators of intercellular communication and participate in numerous physiological and pathological processes in the body. This study aims to introduce the research status, analyze the research hotspots, and predict the development trend through bibliometric analysis of MSC-EVs.

Methods: We searched all relevant literature on MSC-EVs from 2009 to 2021 in the Web of Science. R-bibliometrix, VOSviewer, and CiteSpace software were used to visualize the quantitative analysis of the published literature, including co-authorship, co-occurrence, citation, and co-citation, to provide objective presentation and predictions in the field.

Results: A total of 1595 articles and reviews on MSC-EVs published between 2009 and 2021 were identified. The annual publication outputs increased at an exponential rate, reaching as high as 555 publications in 2021. China contributed the most publications (n = 899, 56.36%) and had the most citations (n = 24,210). The United States had the strongest intensity of cooperation in this field. Shanghai Jiao Tong University had the maximum number of publications (n = 79). In terms of the number of publications and co-citations, the journal of Stem cell research & therapy ranked first. Camussi G was the most productive and most cited author. The top three themes in the research area were cell biology, research experimental medicine, and biochemistry molecular biology. Keyword co-occurrence and co-citation clustering analysis revealed that studies of MSC-EVs covered cellular origin (bone marrow mesenchymal stem cell, adipose-derived mesenchymal stem cell), injurious diseases (spinal cord injury, acute lung injury, ischemia/reperfusion injury, acute kidney injury, traumatic brain injury), tumor (breast cancer, tumor microenvironment), biological processes (drug delivery system, angiogenesis, inflammation, proliferation, differentiation, senescence), and molecular mechanisms (signaling pathway, signal transduction, oxidative stress, VEGF, TGF β).

Conclusions: Studies on MSC-EVs have shown a steep growth trend in recent years. Available studies mostly focused on the therapeutic effects and underlying mechanisms of MSC-EVs in aplastic diseases. Multidisciplinary integration is a development trend in this field, and senescence-related topics might be the focus of future research on MSC-EVs.

Intra-Articular Injection of Adipose-Derived Stem Cells Ameliorates Pain and Cartilage Anabolism/Catabolism in Osteoarthritis: Preclinical and Clinical Evidences

Background: Osteoarthritis (OA) is the most common joint disorder, lacking disease-modifying treatments. Adipose-derived mesenchymal stem cells (ADSCs) are adult multipotent stromal cells obtained from fat tissue, which holds great potential in treating OA. This study aimed to evaluate the anti-OA efficacy of ADSCs from preclinical and clinical facets and explore the underlying mechanism of action.

Methods:In vivo, a single dose of 5 × 10⁵ ADSCs was injected into the knee joints of monoiodoacetate-induced OA rat model. The levels of metabolic and hypertrophic molecules (MMP13, Collagen II, Collagen X) of chondrocytes were measured by immunohistochemistry. In vitro, cell viability assay was conducted to detect the proliferation ability of chondrocytes treated with ADSCs conditioned medium (ADSCs-CM). Quantitative real-time polymerase chain reaction and Western blot assays were applied to explore the mechanism of action of ADSCs. Moreover, a retrospective analysis was conducted to determine the clinical efficacy and safety of ADSCs on OA patients.

Results: The animal study showed that ADSCs significantly alleviated OA cartilage lesions in rats, as was confirmed by downregulation of the MMP13 and Collagen X and upregulation of the Collagen II. In vitro data showed that ADSCs-CM promoted the proliferation of chondrocytes, and significantly restored the IL-1β-induced abnormal expressions of molecular markers IL-6, Aggrecan, MMP3, MMP13, Collagen II, Collagen X, ADAMTS5, ADAMTS9, SOX6, and SOX9 in chondrocytes. Such regulatory effects of ADSCs-CM on the proliferation and these anabolic, catabolic, and hypertrophic markers of chondrocytes suggested a paracrine-based mode of action of ADSCs. Furthermore, the clinical data showed that ADSCs reduced pain and repaired cartilage damage in OA patients, with no adverse events.

Conclusion: This study demonstrated the anti-OA efficacy, safety, and a paracrine-based mechanism of ADSCs, providing a promising cell-based therapeutic option for OA treatment.

Mesenchymal Stem Cell-Derived Extracellular Vesicles for Osteoarthritis Treatment: Extracellular Matrix Protection, Chondrocyte and Osteocyte Physiology, Pain and Inflammation Management

Osteoarthritis (OA) is a common degenerative disease that can lead to persistent pain and motion restriction. In the last decade, stem cells, particularly mesenchymal stem cells (MSCs), have been explored as a potential alternative OA therapy due to their regenerative capacity. Furthermore, it has been shown that trophic factors enveloped in extracellular vesicles (EVs), including exosomes, are a crucial aspect of MSC-based treatment for OA. Evidently, EVs derived from different MSC sources might rescue the OA phenotype by targeting many biological processes associated with cartilage extracellular matrix (ECM) degradation and exerting protective effects on different joint cell types. Despite this advancement, different studies employing EV treatment for OA have revealed reverse outcomes depending on the EV cargo, cell source, and pathological condition. Hence, in this review, we aim to summarize and discuss the possible effects of MSC-derived EVs based on recent findings at different stages of OA development, including effects on cartilage ECM, chondrocyte biology, osteocytes and bone homeostasis, inflammation, and pain management. Additionally, we discuss further strategies and technical advances for manipulating EVs to specifically target OA to bring the therapy closer to clinical use.

Role of extracellular vesicles from adipose tissue- and bone marrow-mesenchymal stromal cells in endothelial proliferation and chondrogenesis

The secretome of mesenchymal stromal cells (MSCs) derived from different tissue sources is considered an innovative therapeutic tool for regenerative medicine. Although adipose tissue‐and bone marrow‐derived MSCs (ADSCs and BMSCs, respectively) share many biological features, the different tissue origins can be mirrored by variations in their secretory profile, and in particular in the secreted extracellular vesicles (EVs). In this study, we carried out a detailed and comparative characterization of middle‐ and small‐sized EVs (mEVs and sEVs, respectively) released by either ADSCs or BMSCs. Their involvement in an endochondral ossification setting was investigated using ex vivo metatarsal culture models that allowed to explore both blood vessel sprouting and bone growth plate dynamics. Although EVs separated from both cell sources presented similar characteristics in terms of size, concentration, and marker expression, they exhibited different characteristics in terms of protein content and functional effects. ADSC‐EVs overexpressed pro‐angiogenic factors in comparison to the BMSC‐counterpart, and, consequently, they were able to induce a significant increase in endothelial cord outgrowth. On the other hand, BMSC‐EVs contained a higher amount of pro‐differentiation and chemotactic proteins, and they were able to prompt growth plate organization. The present study highlights the importance of selecting the appropriate cell source of EVs for targeted therapeutic applications.