The role of extracellular vesicles in osteoarthritis treatment via microenvironment regulation

Intelligent Nanomaterials Design for Osteoarthritis Managements

Osteoarthritis (OA) is the most prevalent degenerative joint disorder, characterized by progressive joint degradation, pain, and diminished mobility, all of which collectively impair patients' quality of life and escalate healthcare expenditures. Current treatment options are often inadequate due to limited efficacy, adverse side effects, and temporary symptom relief, underscoring the urgent need for more effective therapeutic strategies. Recent advancements in nanomaterials and nanomedicines offer promising solutions by improving drug bioavailability, reducing side effects and providing targeted therapeutic benefits. This review critically examines the pathogenesis of OA, highlights the limitations of existing treatments, and explores the latest innovations in intelligent nanomaterials design for OA therapy, with an emphasis on their engineered properties, therapeutic mechanisms, and translational potential in clinical application. By compiling recent findings, this work aims to inspire further exploration and innovation in nanomedicine, ultimately advancing the development of more effective and personalized OA therapies.

Exosomes of stem cells: a potential frontier in the treatment of osteoarthritis

The aging population has led to a global issue of osteoarthritis (OA), which not only impacts the quality of life for patients but also poses a significant economic burden on society. While biotherapy offers hope for OA treatment, currently available treatments are unable to delay or prevent the onset or progression of OA. Recent studies have shown that as nanoscale bioactive substances that mediate cell communication, exosomes from stem cell sources have led to some breakthroughs in the treatment of OA and have important clinical significance. This paper summarizes the mechanism and function of stem cell exosomes in delaying OA and looks forward to the development prospects and challenges of exosomes.

Extracellular Vesicles Derived from Human Umbilical Mesenchymal Stem Cells Transfected with miR-7704 Improved Damaged Cartilage and Reduced Matrix Metallopeptidase 13

We aimed to explore the therapeutic efficacy of miR-7704-modified extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (HUCMSCs) for osteoarthritis (OA) treatment. In vitro experiments demonstrated the successful transfection of miR-7704 into HUCMSCs and the isolation of EVs from these cells. In vivo experiments used an OA mouse model to assess the effects of the injection of miR-7704-modified EVs intra-articularly. Walking capacity (rotarod test), cartilage morphology, histological scores, and the expression of type II collagen, aggrecan, interleukin-1 beta, and matrix metalloproteinase 13 (MMP13) in the cartilage were evaluated. The EVs were characterized to confirm their suitability for therapeutic use. IL-1beta-treated chondrocytes increased type II collagen and decreased MMP13 after treatment with miR-7704-overexpressed EVs. In vivo experiments revealed that an intra-articular injection of miR-7704-overexpressed EVs significantly improved walking capacity, preserved cartilage morphology, and resulted in higher histological scores compared to in the controls. Furthermore, the decreased expression of MMP13 in the cartilage post treatment suggests a potential mechanism for the observed therapeutic effects. Therefore, miR-7704-overexpressed EVs derived from HUCMSCs showed potential as an innovative therapeutic strategy for treating OA. Further investigations should focus on optimizing dosage, understanding mechanisms, ensuring safety and efficacy, developing advanced delivery systems, and conducting early-phase clinical trials to establish the therapeutic potential of HUCMSC-derived EVs for OA management.

Harnessing exosomes for advanced osteoarthritis therapy

Exosomes are nanosized, lipid membrane vesicles secreted by cells, facilitating intercellular communication by transferring cargo from parent to recipient cells. This capability enables biological crosstalk across multiple tissues and cells. Extensive research has been conducted on their role in the pathogenesis of degenerative musculoskeletal diseases such as osteoarthritis (OA), a chronic and painful joint disease that particularly affects cartilage. Currently, no effective treatment exists for OA. Given that exosomes naturally modulate synovial joint inflammation and facilitate cartilage matrix synthesis, they are promising candidates as next generation nanocarriers for OA therapy. Recent advancements have focused on engineering exosomes through endogenous and exogenous approaches to enhance their joint retention, cartilage and chondrocyte targeting properties, and therapeutic content enrichment, further increasing their potential for OA drug delivery. Notably, charge-reversed exosomes that utilize electrostatic binding interactions with cartilage anionic aggrecan glycosaminoglycans have demonstrated the ability to penetrate the full thickness of early-stage arthritic cartilage tissue following intra-articular administration, maximizing their therapeutic potential. These exosomes offer a non-viral, naturally derived, cell-free carrier for OA drug and gene delivery applications. Efforts to standardize exosome harvest, engineering, and property characterization methods, along with scaling up production, will facilitate more efficient and rapid clinical translation. This article reviews the current state-of-the-art, explores opportunities for exosomes as OA therapeutics, and identifies potential challenges in their clinical translation.

Functional Nanomaterials for the Treatment of Osteoarthritis

Osteoarthritis (OA) is the most common degenerative joint disease, affecting more than 595 million people worldwide. Nanomaterials possess superior physicochemical properties and can influence pathological processes due to their unique structural features, such as size, surface interface, and photoelectromagnetic thermal effects. Unlike traditional OA treatments, which suffer from short half-life, low stability, poor bioavailability, and high systemic toxicity, nanotherapeutic strategies for OA offer longer half-life, enhanced targeting, improved bioavailability, and reduced systemic toxicity. These advantages effectively address the limitations of traditional therapies. This review aims to inspire researchers to develop more multifunctional nanomaterials and promote their practical application in OA treatment.

Logic-Based Strategy for Spatiotemporal Release of Dual Extracellular Vesicles in Osteoarthritis Treatment

To effectively treat osteoarthritis (OA), the existing inflammation must be reduced before the cartilage damage can be repaired; this cannot be achieved with a single type of extracellular vesicles (EVs). Here, a hydrogel complex with logic-gates function is proposed that can spatiotemporally controlled release two types of EVs: interleukin 10 (IL-10)+ EVs to promote M2 polarization of macrophage, and SRY-box transcription factor 9 (SOX9)+ EVs to increase cartilage matrix synthesis. Following dose-of-action screening, the dual EVs are loaded into a matrix metalloporoteinase 13 (MMP13)-sensitive self-assembled peptide hydrogel (KM13E) and polyethylene glycol diacrylate/gelatin methacryloyl-hydrogel microspheres (PGE), respectively. These materials are mixed to form a "microspheres-in-gel" KM13E@PGE system. In vitro, KM13E@PGE abruptly released IL-10+ EVs after 3 days and slowly released SOX9+ EVs for more than 30 days. In vivo, KM13E@PGE increased the CD206+ M2 macrophage proportion in the synovial tissue and decreased the tumor necrosis factor-α and IL-1β levels. The aggrecan and SOX9 expressions in the cartilage tissues are significantly elevated following inflammation subsidence. This performance is not achieved using anti-inflammatory or cartilage repair therapy alone. The present study provides an injectable, integrated delivery system with spatiotemporal control release of dual EVs, and may inspire logic-gates strategies for OA treatment.

Recent advances in extracellular vesicle engineering and its applications to regenerative medicine

Extracellular vesicles (EVs) are nanosized particles that are released from cells and reflect the characteristics of the mother cell. Recently, the EVs have been used in several types of studies across many different fields. In the field of EV research, multiple cell culture and EV isolation techniques have been highlighted in importance. Various strategies, including exclusive component culture media, three-dimensional (3D) cultures, and hypoxic conditions, have been proposed for the cell culture to control function of the EVs. Ultracentrifugation, ultrafiltration, precipitation, and tangential flow filtration (TFF) have been utilized for EV isolation. Although isolated EVs have their own functionalities, several researchers are trying to functionalize EVs by applying various engineering approaches. Gene editing, exogenous, endogenous, and hybridization methods are the four well-known types of EV functionalization strategies. EV engineered through these processes has been applied in the field of regenerative medicine, including kidney diseases, osteoarthritis, rheumatoid arthritis, nervous system-related diseases, and others. In this review, it was focused on engineering approaches for EV functionalization and their applications in regenerative medicine.

Kidney tissue regeneration using bioactive scaffolds incorporated with differentiating extracellular vesicles and intermediate mesoderm cells

BACKGROUND

To overcome the limitations of current alternative therapies for chronic kidney disease (CKD), tissue engineering-mediated regeneration strategies have demonstrated the possibilities for complete kidney tissue regeneration. Given the challenges associated with the reproducibility of renal basal cells, the incorporation of intermediate mesoderm (IM) cells and bioactive materials to control bioactivities of cells with supported scaffolds should be considered as a viable approach to enable the regeneration of the complex kidney structure via renal differentiation.

METHODS

We developed PMEZ scaffolds by combining crucial bioactive components, such as ricinoleic acid-grafted Mg(OH)2 (M), extracellular matrix (E), and alpha lipoic acid-conjugated ZnO (Z) integrated into biodegradable porous PLGA (P) platform. Additionally, we utilized differentiating extracellular vesicles (dEV) isolated during intermediate mesoderm differentiation into kidney progenitor cells, and IM cells were serially incorporated to facilitate kidney tissue regeneration through their differentiation into kidney progenitor cells in the 3/4 nephrectomy mouse model.

RESULTS

The use of differentiating extracellular vesicles facilitated IM differentiation into kidney progenitor cells without additional differentiation factors. This led to improvements in various regeneration-related bioactivities including tubule and podocyte regeneration, anti-fibrosis, angiogenesis, and anti-inflammation. Finally, implanting PMEZ/dEV/IM scaffolds in mouse injury model resulted in the restoration of kidney function.

CONCLUSIONS

Our study has demonstrated that utilizing biodegradable PLGA-based scaffolds, which include multipotent cells capable of differentiating into various kidney progenitor cells along with supporting components, can facilitate kidney tissue regeneration in the mouse model that simulates CKD through 3/4 nephrectomy.

The Evolution of Current Concept of the Reconstructive Ladder in Plastic Surgery: The Emerging Role of Translational Medicine

Plastic surgeons have used the reconstructive ladder for many decades as a standard directory for complex trauma reconstruction with the goal of repairing body structures and restoring functionality. This consists of different surgical maneuvers, such as secondary intention and direct tissue closure, as well as more complex methods such as local tissue transfer and free flap. The reconstructive ladder represents widely known options achievable for tissue reconstruction and wound closure that puts at the bottom rung the simplest methods of reconstruction and strengthens the complexity by moving upward. Regenerative medicine and surgery constitute a quickly spreading area of translational research that can be employed by minimally invasive surgical strategies, with the aim of regenerating cells and tissues in vivo in order to reestablish normal function through the intrinsic potential of cells, in combination with biomaterials and appropriate biochemical stimuli. These translational procedures have the aim of creating an appropriate microenvironment capable of supporting the physiological cellular function to generate the desired cells or tissues and to generate parenchymal, stromal, and vascular components on demand, and above all to produce intelligent materials capable of determining the fate of cells. Smart technologies have been grown that give extra "rungs" on the classic reconstructive ladder to integrate a more holistic, patient-based approach with improved outcomes. This commentary presents the evolution of the traditional concept of the reconstructive ladder in the field of plastic surgery into a new course with the aim of achieving excellent results for soft tissue reconstruction by applying innovative technologies and biologically active molecules for a wide range of surgical diseases.

Engineered extracellular vesicles as therapeutics of degenerative orthopedic diseases

Degenerative orthopedic diseases, as a global public health problem, have made serious negative impact on patients' quality of life and socio-economic burden. Traditional treatments, including chemical drugs and surgical treatments, have obvious side effects and unsatisfactory efficacy. Therefore, biological therapy has become the focus of researches on degenerative orthopedic diseases. Extracellular vesicles (EVs), with superior properties of immunoregulatory, growth support, and drug delivery capabilities, have emerged as a new cell-free strategy for the treatment of many diseases, including degenerative orthopedic diseases. An increasing number of studies have shown that EVs can be engineered through cargo loading, surface modification, and chemical synthesis to improve efficiency, specificity, and safety. Herein, a comprehensive overview of recent advances in engineering strategies and applications of engineered EVs as well as related researches in degenerative orthopedic diseases, including osteoarthritis (OA), osteoporosis (OP), intervertebral disc degeneration (IDD) and osteonecrosis of the femoral head (ONFH), is provided. In addition, we analyze the potential and challenges of applying engineered EVs to clinical practice.

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.

High-glutathione mesenchymal stem cells isolated using the FreSHtracer probe enhance cartilage regeneration in a rabbit chondral defect model

BACKGROUND

Mesenchymal stem cells (MSCs) are a promising cell source for cartilage regeneration. However, the function of MSC can vary according to cell culture conditions, donor age, and heterogeneity of the MSC population, resulting in unregulated MSC quality control. To overcome these limitations, we previously developed a fluorescent real-time thiol tracer (FreSHtracer) that monitors cellular levels of glutathione (GSH), which are known to be closely associated with stem cell function. In this study, we investigated whether using FreSHtracer could selectively separate high-functioning MSCs based on GSH levels and evaluated the chondrogenic potential of MSCs with high GSH levels to repair cartilage defects in vivo.

METHODS

Flow cytometry was conducted on FreSHtracer-loaded MSCs to select cells according to their GSH levels. To determine the function of FreSHtracer-isolated MSCs, mRNA expression, migration, and CFU assays were conducted. The MSCs underwent chondrogenic differentiation, followed by analysis of chondrogenic-related gene expression. For in vivo assessment, MSCs with different cellular GSH levels or cell culture densities were injected in a rabbit chondral defect model, followed by histological analysis of cartilage-regenerated defect sites.

RESULTS

FreSHtracer successfully isolated MSCs according to GSH levels. MSCs with high cellular GSH levels showed enhanced MSC function, including stem cell marker mRNA expression, migration, CFU, and oxidant resistance. Regardless of the stem cell tissue source, FreSHtracer selectively isolated MSCs with high GSH levels and high functionality. The in vitro chondrogenic potential was the highest in pellets generated by MSCs with high GSH levels, with increased ECM formation and chondrogenic marker expression. Furthermore, the MSCs' function was dependent on cell culture conditions, with relatively higher cell culture densities resulting in higher GSH levels. In vivo, improved cartilage repair was achieved by articular injection of MSCs with high levels of cellular GSH and MSCs cultured under high-density conditions, as confirmed by Collagen type 2 IHC, Safranin-O staining and O'Driscoll scores showing that more hyaline cartilage was formed on the defects.

CONCLUSION

FreSHtracer selectively isolates highly functional MSCs that have enhanced in vitro chondrogenesis and in vivo hyaline cartilage regeneration, which can ultimately overcome the current limitations of MSC therapy.

MSC-EVs alleviate osteoarthritis by regulating microenvironmental cells in the articular cavity and maintaining cartilage matrix homeostasis

Osteoarthritis (OA), a common cause of chronic articular cartilage degeneration, is the main cause of disability in older adults and severely affects quality of life. Multiple factors are involved in the pathogenesis of OA, resulting in imbalance in the homeostasis of the joint cavity microenvironment, which exacerbates the disease. Because of the deficiency of blood vessels and nerves in cartilage, existing therapies to promote cartilage healing are relatively ineffective. Mesenchymal stem cell (MSC)-related therapies have achieved positive outcomes for the treatment of OA, and these beneficial effects have been confirmed to be largely mediated by extracellular vesicles (EVs). MSC-derived EVs (MSC-EVs) have been demonstrated to participate in the regulation of chondrocyte function, to have anti-inflammatory and immunomodulatory effects, and to alleviate metabolic disorders of the extracellular matrix, thereby slowing the progression of OA. In addition, engineered MSC-EVs can enrich therapeutic molecules and optimize administration to enhance their therapeutic effects on OA. A thorough understanding of the endogenous properties of EVs and related engineering strategies could help researchers develop more precise control therapy for OA.

Extracellular vesicles in osteoarthritis of peripheral joint and temporomandibular joint

Osteoarthritis (OA) is a disabling disease with significant morbidity worldwide. OA attacks the large synovial joint, including the peripheral joints and temporomandibular joint (TMJ). As a representative of peripheral joint OA, knee OA shares similar symptoms with TMJ OA. However, these two joints also display differences based on their distinct development, anatomy, and physiology. Extracellular vesicles (EVs) are phospholipid bilayer nanoparticles, including exosomes, microvesicles, and apoptotic bodies. EVs contain proteins, lipids, DNA, micro-RNA, and mRNA that regulate tissue homeostasis and cell-to-cell communication, which play an essential role in the progression and treatment of OA. They are likely to partake in mechanical response, extracellular matrix degradation, and inflammatory regulation during OA. More evidence has shown that synovial fluid and synovium-derived EVs may serve as OA biomarkers. More importantly, mesenchymal stem cell-derived EV shows a therapeutic effect on OA. However, the different function of EVs in these two joints is largely unknown based on their distinct biological characteristic. Here, we reviewed the effects of EVs in OA progression and compared the difference between the knee joint and TMJ, and summarized their potential therapeutic role in the treatment of OA.