Exosome-based strategy for degenerative disease in orthopedics: Recent progress and perspectives

Pathological mechanisms and related markers of steroid-induced osteonecrosis of the femoral head

BACKGROUND

Osteonecrosis of the femoral head (ONFH) is a refractory orthopedic disease with a high disability rate. Long-term administration of steroids is the most common pathogenic factor for non-traumatic ONFH. Early diagnosis of steroid-induced osteonecrosis of the femoral head (SONFH) is difficult and mainly depends on imaging.

OBJECTIVES

The objectives of this review were to examine the pathological mechanisms of SONFH, summarize related markers of SONFH, and identify areas for future studies.

METHODS

We reviewed studies on pathological mechanisms and related markers of SONFH and discussed the relationship between them, as well as clinical applications and the outlook of potential markers.

RESULTS

The pathological mechanisms of SONFH included decreased osteogenesis, lipid accumulation, increased intraosseous pressure, and microcirculation disruption. Differential proteomics and genomics play crucial roles in the occurrence, progression, and outcome of SONFH, providing novel insights into SONFH. Additionally, the biological functions of mesenchymal stem cells (MSCs) and exosomes (Exos) in SONFH have attracted increasing attention.

CONCLUSIONS

The pathological mechanisms of SONFH are complex. The related markers mentioned in the current review can predict the occurrence and progression of SONFH, which will help provide effective early clinical prevention and treatment strategies for SONFH.

Therapeutic Effects of Puerarin Loaded Bone Marrow Mesenchymal Stem Cell-Derived Exosomes in a Rat Model of Osteoarthritis

Osteoarthritis (OA) is the most prevalent chronic degenerative joint disease among the aged population. The primary objective of this study was to assess the therapeutic potential of puerarin loaded bone marrow mesenchymal stem cell-derived exosomes (Pue@BMSC-Exo), and reveal their inflammatory regulating mechanisms through affecting the nuclear factor kappa-B (NF-κB) signaling pathway. In this study, exosomes derived from BMSCs were isolated and identified. Cell proliferation and migration were evaluated by CCK-8 and scratch methods. Furthermore, histological and micro-computed tomography analysis were performed to assess alterations of articular cartilage in OA rats. Results showed that BMSC-Exo and Pue@BMSC-Exo conformed with the basic characteristics of exosomes. BMSC-Exo increased the solubility of Pue and enhanced drug uptake by chondrocytes. In addition, Pue@BMSC-Exo stimulated proliferation and migration of chondrocyte, and also promoted cartilage repair by reducing matrix metalloproteinase MMP13 production and increasing type II collagen (Col2) synthesis. Furthermore, Pue@BMSC-Exo, by effectively inhibiting the NF-κB signaling pathway, reduced the production of inflammatory mediators and attenuated the release of the inflammatory marker nitric oxide (NO), ultimately ameliorating the damage of chondrocyte. These findings exhibited the potential therapeutic significance of Pue@BMSC-Exo in OA and warranted further exploration in clinical applications.

Recent trends of stem cell therapies in the management of orthopedic surgical challenges

Emerged health-related problems especially with increasing population and with the wider occurrence of these issues have always put the utmost concern and led medicine to outgrow its usual mode of treatment, to achieve better outcomes. Orthopedic interventions are one of the most concerning hitches, requiring advancement in several issues, that show complications with conventional approaches. Advanced studies have been undertaken to address the issue, among which stem cell therapy emerged as a better area of growth. The capacity of the stem cells to renovate themselves and adapt into different cell types made it possible to implement its use as a regenerative slant. Harvesting the stem cells, particularly mesenchymal stem cells (MSCs) is easier and can be further grown in vitro . In this review, we have discussed orthopedic-related issues including bone defects and fractures, nonunions, ligament and tendon injuries, degenerative changes, and associated conditions, which require further approaches to execute better outcomes, and the advanced strategies that can be tagged along with various ways of application of MSCs. It aims to objectify the idea of stem cells, with a major focus on the application of MSCs from different sources in various orthopedic interventions. It also discusses the limitations, and future scopes for further approaches in the field of regenerative medicine. The involvement of MSCs may transition the procedures in orthopedic interventions from predominantly surgical substitution and reconstruction to bio-regeneration and prevention. Nevertheless, additional improvements and evaluations are required to explore the effectiveness and safety of mesenchymal stem cell treatment in orthopedic regenerative medicine.

Advanced approaches of the use of circRNAs as a replacement for cancer therapy

Cancer is a broad name for a group of diseases in which abnormal cells grow out of control and are characterized by their complexity and recurrence. Although there has been progress in cancer therapy with the entry of precision medicine and immunotherapy, cancer incidence rates have increased globally. Non-coding RNAs in the form of circular RNAs (circRNAs) play crucial roles in the pathogenesis, clinical diagnosis, and therapy of different diseases, including cancer. According to recent studies, circRNAs appear to serve as accurate indicators and therapeutic targets for cancer treatment. However, circRNAs are promising candidates for cutting-edge cancer therapy because of their distinctive circular structure, stability, and wide range of capabilities; many challenges persist that decrease the applications of circRNA-based cancer therapeutics. Here, we explore the roles of circRNAs as a replacement for cancer therapy, highlight the main challenges facing circRNA-based cancer therapies, and discuss the key strategies to overcome these challenges to improve advanced innovative therapies based on circRNAs with long-term health effects.

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

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

Unlocking the potential of exosomes: a breakthrough in the theranosis of degenerative orthopaedic diseases

Degenerative orthopaedic diseases pose a notable worldwide public health issue attributable to the global aging population. Conventional medical approaches, encompassing physical therapy, pharmaceutical interventions, and surgical methods, face obstacles in halting or reversing the degenerative process. In recent times, exosome-based therapy has gained widespread acceptance and popularity as an effective treatment for degenerative orthopaedic diseases. This therapeutic approach holds the potential for "cell-free" tissue regeneration. Exosomes, membranous vesicles resulting from the fusion of intracellular multivesicles with the cell membrane, are released into the extracellular matrix. Addressing challenges such as the rapid elimination of natural exosomes in vivo and the limitation of drug concentration can be effectively achieved through various strategies, including engineering modification, gene overexpression modification, and biomaterial binding. This review provides a concise overview of the source, classification, and preparation methods of exosomes, followed by an in-depth analysis of their functions and potential applications. Furthermore, the review explores various strategies for utilizing exosomes in the treatment of degenerative orthopaedic diseases, encompassing engineering modification, gene overexpression, and biomaterial binding. The primary objective is to provide a fresh viewpoint on the utilization of exosomes in addressing bone degenerative conditions and to support the practical application of exosomes in the theranosis of degenerative orthopaedic diseases.

Young human plasma-derived extracellular vesicles rescue and reactivate IL-1β and TNF-α treated chondrocytes

Osteoarthritis (OA) is a degenerative disease that affects millions of individuals worldwide. Despite its prevalence, the exact causes and mechanisms behind OA are still not fully understood, resulting in a lack of effective treatments to slow down or halt disease progression. Recent research has discovered that extracellular vesicles (EVs) present in the circulation of young mice have a remarkable ability to activate musculoskeletal stem cells in elderly mice. Conversely, EVs derived from elderly mice do not exhibit the same potential, indicating that EVs obtained from young individuals may hold promise to activate aging cells in degenerative tissue. However, it remains unknown whether EVs derived from young individuals can also address cartilage degeneration caused by aging. In this study, we first evaluated EVs derived from young human plasma (YEVs) and EVs derived from old human plasma (OEVs) in an in vitro experiment using chondrocytes. The results revealed that YEVs effectively stimulated chondrocyte proliferation and migration, while OEVs from old plasma did not exhibit a similar effect. Given that OA represents a more complex inflammatory microenvironment, we further determine whether the benefits of YEVs on chondrocytes can be maintained in this context. Our findings indicate that YEVs have the ability to positively regulate chondrocyte function and protect them against apoptosis induced by IL-1β and TNF-α in an in vitro OA model. Furthermore, we discovered that lyophilized EVs could be stored under mild conditions without any alterations in their physical characteristics. Considering the exceptional therapeutic effects and the wide availability of EVs from young plasma, they hold significant promise as a potential approach to activate chondrocytes and promote cartilage regeneration in early-stage OA.

Adipose-derived stem cell exosomes act as delivery vehicles of microRNAs in a dog model of chronic hepatitis

Exosomes are nanosized extracellular vesicles secreted by all cell types, including canine adipose-derived stem cells (cADSCs). By mediating intercellular communication, exosomes modulate the biology of adjacent and distant cells by transferring their cargo. In the present work after isolation and characterization of exosomes derived from canine adipose tissue, we treated the same canine donors affected by hepatopathies with the previously isolated exosomes. We hypothesize that cADSC-sourced miRNAs are among the factors responsible for a regenerative and anti-inflammatory effect in the treatment of hepatopathies in dogs, providing the clinical veterinary field with an effective and innovative cell-free therapy. Exosomes were isolated and characterized for size, distribution, surface markers, and for their miRNomic cargo by microRNA sequencing. 295 dogs affected with hepatopathies were treated and followed up for 6 months to keep track of their biochemical marker levels. Results confirmed that exosomes derived from cADSCs exhibited an average diameter of 91 nm, and positivity to 8 known exosome markers. The administration of exosomes to dogs affected by liver-associated inflammatory pathologies resulted in the recovery of the animal alongside the normalization of biochemical parameters of kidney function. In conclusion, cADSCs-derived exosomes are a promising therapeutic tool for treating inflammatory disorders in animal companions.

M2 macrophage-derived exosomal miR-26b-5p regulates macrophage polarization and chondrocyte hypertrophy by targeting TLR3 and COL10A1 to alleviate osteoarthritis

Osteoarthritis (OA) is one of the most prevalent chronic musculoskeletal diseases among the elderly population. In this study, macrophage-derived exosomes were isolated and identified. Exosomes were subjected to microRNA (miRNA) sequencing and bioinformatic analysis, and differentially expressed miRNAs were verified. miR-26b-5p target genes were confirmed through target-site mutation combined with a dual-luciferase reporter assay. The effects of miR-26b-5p on macrophage polarization and chondrocyte hypertrophy were assessed in vitro. miR-26b-5p agomir was applied to mice with OA induced by anterior cruciate ligament transection (ACLT). The therapeutic effects of miR-26b-5p were evaluated via pain behavior experiments and histological observations. In vitro, miR-26b-5p repolarized M1 macrophages to an anti-inflammatory M2 type by targeting the TLR3 signaling pathway. miR-26b-5p could target COL10A1, further inhibiting chondrocyte hypertrophy induced by M1 macrophage-conditioned medium (M1-CM). In vivo, miR-26b-5p agomir ameliorated gait abnormalities and mechanical allodynia in OA mice. miR-26b-5p treatment attenuated synovitis and cartilage degeneration, thereby delaying OA progression. In conclusion, M2 macrophage-derived exosomal miR-26b-5p could protect articular cartilage and ameliorate gait abnormalities in OA mice by targeting TLR3 and COL10A1. miR-26b-5p further affected macrophage polarization and chondrocyte hypertrophy. Thus, this exosomal miR-26b-5p-based strategy might be a potential method for OA treatment.

Construction of a novel cell-free tracheal scaffold promoting vascularization for repairing tracheal defects

Functional vascularization is crucial for maintaining the long-term patency of tissue-engineered trachea and repairing defective trachea. Herein, we report the construction and evaluation of a novel cell-free tissue-engineered tracheal scaffold that effectively promotes vascularization of the graft. Our findings demonstrated that exosomes derived from endothelial progenitor cells (EPC-Exos) enhance the proliferation, migration, and tube formation of endothelial cells. Taking advantage of the angiogenic properties of EPC-Exos, we utilized methacrylate gelatin (GelMA) as a carrier for endothelial progenitor cell exosomes and encapsulated them within a 3D-printed polycaprolactone (PCL) scaffold to fabricate a composite tracheal scaffold. The results demonstrated the excellent angiogenic potential of the methacrylate gelatin/vascular endothelial progenitor cell exosome/polycaprolactone tracheal scaffold. Furthermore, in vivo reconstruction of tracheal defects revealed the capacity of this composite tracheal stent to remodel vasculature. In conclusion, we have successfully developed a novel tracheal stent composed of methacrylate gelatin/vascular endothelial progenitor exosome/polycaprolactone, which effectively promotes angiogenesis for tracheal repair, thereby offering significant prospects for clinical and translational medicine.

Strategies for Cartilage Repair in Osteoarthritis Based on Diverse Mesenchymal Stem Cells-Derived Extracellular Vesicles

Osteoarthritis (OA) causes disability and significant economic and social burden. Cartilage injury is one of the main pathological features of OA, and is often manifested by excessive chondrocyte death, inflammatory response, abnormal bone metabolism, imbalance of extracellular matrix (ECM) metabolism, and abnormal vascular or nerve growth. Regrettably, due to the avascular nature of cartilage, its capacity to repair is notably limited. Mesenchymal stem cells-derived extracellular vesicles (MSCs-EVs) play a pivotal role in intercellular communication, presenting promising potential not only as early diagnostic biomarkers in OA but also as efficacious therapeutic strategy. MSCs-EVs were confirmed to play a therapeutic role in the pathological process of cartilage injury mentioned above. This paper comprehensively provides the functions and mechanisms of MSCs-EVs in cartilage repair.

Mir-25-3p in extracellular vesicles from fibroblast-like synoviocytes alleviates pyroptosis of chondrocytes in knee osteoarthritis

Knee osteoarthritis (KOA) is defined as a joint disease that occurs mostly among elderly people. Fibroblast-like synoviocytes-derived extracellular vesicles (FLS-EVs) have impacts on the treatment of OA. This study elucidated the mechanism of miR-25-3p in pyroptosis of chondrocytes in KOA. FLSs and EVs were extracted from neonatal mice; destabilization of the medial meniscus (DMM) was used to simulate KOA in mice, followed by the evaluation of cartilage damage and the contents of MMP-3 and MMP-13 in KOA mice. Lipopolysaccharide (LPS) was used to induce inflammation damage in mouse chondrocytes ATDC5, and the cell viability and the expressions of NLRP3, Cleaved-Caspase-1, GSDMD-N, IL-18, and IL-1β were examined. We found that FLS-EV treatment mitigated the knee-joint damage and symptoms of KOA mice, decreased MMP-3 and MMP-13, and inhibited pyroptosis of chondrocytes in DMM mice and LPS-induced ATD5 cells. Then, Cy3-labeled miR-25-3p in mice chondrocytes was observed and the expressions and the binding relation of miR-25-3p and cytoplasmic polyadenylation element-binding protein 1 (CPEB1) were verified. It showed that FLS-EVs carried miR-25-3p into chondrocytes, and upregulated miR-25-3p expression while inhibited CPEB1 transcription, resulting in mitigation of pyroptosis of chondrocytes, and CPEB1 overexpression reversed the inhibition of FLS-EVs on pyroptosis of chondrocytes in KOA.

MATN3 delivered by exosome from synovial mesenchymal stem cells relieves knee osteoarthritis: Evidence from in vitro and in vivo studies

Background

Synovial mesenchymal stem cell (SMSC) exerts chondroprotective effects in osteoarthritis (OA) clinical models. However, the regulatory potentials of SMSC-derived exosomes (SMSC-Exo) in OA still need to be discovered, which attracted our attention.

Methods

The destabilization of the medial meniscus surgery was performed on the knee joints of a mouse OA model, followed by injection of SMSC-Exo. In addition, SMSC-Exo was administrated to mouse chondrocytes to observe the functional and molecular alterations.

Results

Both of SMSC-Exo and overexpression of Matrilin-3 (MATN3) alleviated cartilage destruction and suppressed degradation of extracellular matrix (ECM) in the OA rat model. In addition, assays concerning the in vitro OA model induced by IL-1β showed that SMSC-Exo could promote chondrocyte viability and inhibit autophagy defects. Furthermore, SMSC-Exo achieved the chondroprotective effects through the delivery of MATN3/IL-17A, and MATN3 could suppress the activation of PI3K/AKT/mTOR signaling through IL-17A.

Conclusion

SMSC-Exo exerts beneficial therapeutic effects on OA by preventing ECM degradation and autophagy defects by delivering MATN3/IL-17A.

The Translational Potential of this Article

The translational potential of this study is not only limited to the treatment of knee osteoarthritis but also provides new insights for the treatment of other joint diseases by exploring the mechanism of MATN3. In addition, SMSCExo, as a novel drug carrier, has great potential for treating and diagnosing other diseases. With further research, these findings will provide new directions for developing personalized and innovative treatment options.

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.

Interactions between extracellular vesicles and microbiome in human diseases: New therapeutic opportunities

In recent decades, accumulating research on the interactions between microbiome homeostasis and host health has broadened new frontiers in delineating the molecular mechanisms of disease pathogenesis and developing novel therapeutic strategies. By transporting proteins, nucleic acids, lipids, and metabolites in their versatile bioactive molecules, extracellular vesicles (EVs), natural bioactive cell-secreted nanoparticles, may be key mediators of microbiota-host communications. In addition to their positive and negative roles in diverse physiological and pathological processes, there is considerable evidence to implicate EVs secreted by bacteria (bacterial EVs [BEVs]) in the onset and progression of various diseases, including gastrointestinal, respiratory, dermatological, neurological, and musculoskeletal diseases, as well as in cancer. Moreover, an increasing number of studies have explored BEV-based platforms to design novel biomedical diagnostic and therapeutic strategies. Hence, in this review, we highlight the recent advances in BEV biogenesis, composition, biofunctions, and their potential involvement in disease pathologies. Furthermore, we introduce the current and emerging clinical applications of BEVs in diagnostic analytics, vaccine design, and novel therapeutic development.