Mesenchymal stromal/stem cell (MSC)-derived exosomes are nanoscale extracellular vesicles that have emerged as promising candidates for therapeutic and diagnostic applications because of their unique bioactive cargo, including proteins, lipids, and nucleic acids. These vesicles mitigate concerns of immunogenicity and tumorigenicity associated with MSC-based therapies and offer enhanced stability, higher scalability, and ease of modification. However, the use of MSC-derived exosomes in clinical practice is associated with challenges, including difficulties in isolation, characterization, and standardization. This review explores the biogenesis and structural properties of MSC-derived exosomes and discusses the molecular mechanisms underlying their therapeutic effects. It also discusses ongoing clinical trials on their applications in cancer, cardiovascular, neurological, and regenerative medicine. Preclinical and clinical data have demonstrated the potential of MSC-derived exosomes in enhancing tissue repair, reducing inflammation, and modulating immune responses. Despite these advancements, gaps in scalable production methods, regulatory guidelines, and therapeutic consistency must be addressed. Future innovations in bioengineering, manufacturing, and regulatory frameworks are essential to realize the full potential of MSC-derived exosomes in mainstream medicine.

Mesenchymal stem cells (MSCs), a vital component of the adult stem cell repertoire, are distinguished by their dual capacity for self-renewal and multilineage differentiation. The therapeutic effects of MSCs are primarily mediated through mechanisms such as homing, paracrine signaling, and cellular differentiation. Exosomes (Exos), a type of extracellular vesicles (EVs) secreted by MSCs via the paracrine pathway, play a pivotal role in conveying the biological functions of MSCs. Accumulating evidence from extensive research underscores the remarkable anti-aging potential of both MSCs and their Exos. This review comprehensively explores the impact of MSCs and their Exos on key hallmarks of aging, including genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, impaired macroautophagy, deregulated nutrient-sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, chronic inflammation, and dysbiosis. Furthermore, this paper highlights emerging strategies and novel approaches for modulating the aging process, offering insights into potential therapeutic interventions.

Mesenchymal stem cell (MSC)-based therapy may be a future treatment for myocardial infarction (MI). However, few studies have assessed the therapeutic efficacy of adipose tissue-derived MSCs (ADSCs) obtained from elderly patients in comparison to that of bone marrow-derived MSCs (BMSCs) from the same elderly patients. The metabolomics results revealed a significantly higher L-arginine excretion from aged ADSCs vs BMSCs in hypoxic conditions. This was hypothesized as the possible mechanism that ADSCs showed an improved angiogenic capacity and enhanced the therapeutic effect on ischemic heart diseases.

To investigate the role of L-arginine in enhancing angiogenesis and cardiac protection by comparing ADSCs and BMSCs in hypoxic conditions for MI therapy.

Metabolomic profiling of supernatants from ADSCs and BMSCs under hypoxic conditions were performed. Then, arginine succinate lyase (ASL) overexpression and short hairpin RNA plasmid were prepared and transfected into BMSCs. Subsequently, in vitro wound healing and Matrigel tube formation assays were used to verify the proangiogenetic effects of ADSC positive control, BMSCs, BMSCs ASL short hairpin RNA, BMSCs ASL overexpressed, and BMSC negative control on cocultured human umbilical vein endothelial cells. All sample sizes, which were determined to meet the statistical requirements and be greater than 3, were established on the basis of previously established literature standards. The protein levels of vascular endothelial growth factor (VEGF), basic fibroblast growth factor, etc. were detected. In vivo, the five types of cells were transplanted into the infarcted area of MI rat models, and the therapeutic effects of the transplanted cells were evaluated by echocardiography on cardiac function and by Masson's staining/terminal-deoxynucleotidyl transferase mediated nick end labeling assay/immunofluorescence detection on the infarcted area.

Metabolomic analysis showed that L-arginine was increased. Using ASL gene transfection, we upregulated the production of L-arginine in aged patient-derived BMSCs in vitro, which in turn enhanced mitogen activated protein kinase and VEGF receptor 2 protein expression, VEGF and basic fibroblast growth factor secretion, and inductive angiogenesis to levels comparable to donor-matched ADSCs. After the cell transplantation in vivo, the modified BMSCs as well as ADSCs exhibited decreased apoptotic cells, enhanced vessel formation, reduced scar size, and improved cardiac function in the MI rat model. The therapeutic efficacy decreased by inhibiting L-arginine synthesis.

L-arginine is important for inducing therapeutic angiogenesis for ADSCs and BMSCs in hypoxic conditions. ADSCs have higher L-arginine secretion, which leads to better angiogenesis induction and cardiac protection. ADSC transplantation is a promising autologous cell therapy strategy in the context of the present aging society.

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.

Background/Objectives: Regenerative therapies have gained interest in orthopedic applications for their potential to enhance tissue regeneration, functional recovery, and pain modification. This review evaluates the clinical efficacy of platelet-rich plasma (PRP), mesenchymal stem cells (MSCs), peptide-based treatments, and biomimetic materials in orthopedic care, with a focus on pain reduction and functional outcomes. Methods: A structured literature search in PubMed (January 2009-January 2025) identified 160 studies. After applying inclusion criteria prioritizing randomized controlled trials (RCTs) and clinical trials, 59 studies were included: 20 on PRP, 20 on MSCs, 10 on peptide therapies, and 7 on biomimetics. Data extraction focused on pain reduction and functional recovery, with risk of bias assessed using the Cochrane Risk of Bias (RoB) tool and ROBINS-I tool. A random-effects meta-regression analysis was conducted to evaluate the impact of therapy type, sample size, and risk of bias on reported pain reduction outcomes. Results: Meta-regression analysis identified MSC therapy as the most effective intervention for pain reduction (β = 8.45, p < 0.05), with PRP and peptide-based therapies showing moderate improvements, and biomimetic therapies demonstrating the lowest effect. PRP provided short-term pain relief, particularly in acute injuries and tendon repair, though inconsistencies in preparation methods limited success in chronic conditions. MSC therapies demonstrated cartilage regeneration and early osteoarthritis improvement, but high costs and ethical concerns remain barriers to widespread adoption. Peptide-based therapies and biomimetic materials, including engineered scaffolds and autologous protein solutions, showed promise for infection control and wound healing, though further research is needed to optimize dosing, delivery methods, and long-term safety. Conclusions: Regenerative therapies offer significant potential in orthopedic care, with MSC therapies demonstrating the most reliable regenerative effects, PRP providing short-term symptomatic relief, and peptide-based and biomimetic treatments emerging as promising adjuncts. However, standardized protocols and large-scale clinical trials are needed to establish long-term efficacy and improve clinical translation for broader adoption.

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs), especially, exosomes are considered to have diverse therapeutic effects for various significant diseases. MSC-derived exosomes (MSCex) offer substantial advantages over MSCs due to their long-term preservation, stability, absence of nuclei and fewer adverse effects such as infusion toxicity, thereby paving the way towards regenerative medicine and cell-free therapeutics. These exosomes harbor several cellular contents such as DNA, RNA, lipids, metabolites, and proteins, facilitating drug delivery and intercellular communication. MSCex have the ability to immunomodulate and trigger the anti-inflammatory process hence, playing a key role in alleviating inflammation and enhancing tissue regeneration. In this review, we addressed the anti-inflammatory effects of MSCex and the underlying immunomodulatory pathways. Moreover, we discussed the recent updates on MSCex in treating specific inflammatory diseases, including arthritis, inflammatory bowel disease, inflammatory eye diseases, and respiratory diseases such as asthma and acute respiratory distress syndrome (ARDS), as well as neurodegenerative and cardiac diseases. Finally, we highlighted the challenges in using MSCex as the successful therapeutic tool and discussed future perspectives.

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.

Regeneration dentistry demonstrates significant challenges due to the complexity of different dental structures. This study aimed to investigate osteogenic differentiation of human pulp stem cells (hDPSCs) cultured on a 3D-printed poly lactic acid (PLA) scaffold coated with nano-hydroxyapatite (nHA) and naringin (NAR) as a model for a dental regenerative.

PLA scaffolds were 3D printed into circular discs (10 × 1 mm) and coated with nHA, NAR, or both. Scaffolds were cultured with hDPTCs to identify cellular morphological changes and adhesion over incubation periods of 3, 7, and 21 days using SEM. Then, the osteogenic potential of PLA, PLA/nHA/NAR, or PLA scaffolds coated with MTA elutes (PLA/MTA scaffolds) were evaluated by measuring mineralized tissue deposition using calcium concentration assays and alizarin red staining (ARS). Also, immunofluorescence labelling of alkaline phosphatase (ALP) and dentine sialophosphoprotein (DSPP) within cultured cells were evaluated.

The highest cellular attachment was identified on the PLA/nHA/NAR scaffold, with morphological changes reflecting cellular differentiation. The highest calcium deposition and ARS were recognized in the PLA/nHA/NAR culture, with statistically significant difference (p < 0.05) compared to PLA/MTA. Also, ALP and DSPP markers showed statistically significantly higher (p < 0.05) immunoreactivity in cells cultured within PLA/nHA/NAR compared to PLA/MTA.

The results confirm the osteogenic potential of PLA scaffolds coated with nHA/NAR for future animal and human investigations.

Chondrocyte senescence is an important pathogenic factor causing osteoarthritis (OA) progression through persistently producing pro-inflammatory factors. Mesenchymal stem cells-derived small extracellular vesicles (MSC-sEVs) have shown anti-inflammatory effects in OA models, while persistent existence of senescent chondrocytes still promotes cartilage destruction. Therefore, improving the targeted elimination ability on senescent chondrocytes is required to facilitate the translation of MSC-sEVs in OA treatment. In this study, versatile engineered MSC-sEVs are developed to targetedly clear senescent chondrocytes and maintain cartilage metabolic homeostasis. Specifically, MSC-sEVs are loaded with siRNA mouse double minute 2 homologue (siMDM2) and modified with cartilage-targeting peptide WYRGRL-PEG2K-DSPE (WPD), named WPD-sEVssiMDM2. The results demonstrate versatile modification improves the cellular uptake of MSC-sEVs in chondrocytes, and thus improves the antiaging effects. Importantly, multifunctional modification enhances cartilage penetration ability and extends joint retention time of MSC-sEVs. In both post-traumatic OA mice and naturally aged mice, WPD-sEVssiMDM2 more effectively eliminates senescent chondrocytes and maintained matrix metabolic homeostasis. By using the P53 phosphorylation inhibitor, the essential role MDM2-P53 pathway in the antiaging function of WPD-sEVssiMDM2 on chondrocytes is verified. In ex vivo cultured human OA cartilage explants, it is confirmed that WPD-sEVssiMDM2 alleviates senescent phenotype. Altogether, the findings suggest that WPD-sEVssiMDM2 have promising translational potential for OA treatment.

Extracellular vesicles (EVs), particularly exosomes (EXOs) of various skeletal and stem cells, were shown to delay osteoarthritis (OA) progression, and apoptotic bodies (ABs), another EV subtype, of osteoclasts showed osteoanabolic actions and were involved in the osteoclastic-regulation of local bone formation. Moreover, this study demonstrates that microvesicles (MVs) released by osteoclasts displayed potent pro-chondrogenic, pro-osteogenic, and anti-inflammatory activities. These activities were unique to osteoclastic MVs and were not shared by osteoclastic ABs and EXOs or MVs of other cell types. Because chronic synovial inflammation, progressive articular cartilage erosion, abnormal subchondral bone remodeling, and inability to regenerate articular cartilage are key etiologies of OA, we postulate that the foregoing activities of osteoclastic MVs could simultaneously target multiple etiologies of OA and could thereby be an effective therapy for OA. Accordingly, this study sought to assess the feasibility of an osteoclastic MV-based strategy for OA with a mouse tibial plateau injury model of OA. Briefly, tibial plateau injuries were created on the right knees of adult C57BL/6J mice, MVs were intraarticularly injected into the injured joints biweekly, and the OA progression was monitored histologically at five weeks post-injury. The MV treatment reduced the OA-induced losses of articular cartilage area and thickness, decreased irregularity in the articular cartilage surface, reduced loss of gliding/intermediate zone of articular cartilage, reduced osteophyte formation, suppressed synovial inflammation, and decreased the OARSI OA score. In summary, treatment with osteoclastic MVs delayed or reversed OA progression. Thus, this study supports the feasibility of an osteoclastic MV-based therapy for OA.

The skin functions as the body's primary defense barrier; when compromised, it can lead to dehydration, infection, shock, or potentially life-threatening conditions. Miniature pigs exhibit skin characteristics and healing processes highly analogous to humans. Mesenchymal stem cells contribute to skin injury repair through a paracrine mechanism involving exosomes. This research examines whether adipose-derived MSC exosomes effectively enhance healing following autologous skin grafting in miniature pigs. It also compares the roles and distinctions of ADSCs and ADSC-Exos in inflammatory responses and tissue regeneration. This study found significantly reduced levels of oxidative stress products and pro-inflammatory factors, while antioxidant factors, anti-inflammatory factors, and pro-regenerative factors were elevated, and anti-regenerative factor levels decreased. Moreover, the expression levels of key markers-namely, PI3K, Akt, and mTOR-in the regeneration-associated signaling pathway were increased. The alterations in these indicators indicate that ADSC-Exos can regulate inflammatory responses and promote regeneration. This study provides a novel theoretical foundation for the implementation of acellular therapy in clinical settings.

The progression and severity of periodontitis (PD) are associated with the release of extracellular vesicles by periodontal tissue cells. However, the precise mechanisms through which exosome-related genes (ERGs) influence PD remain unclear. This study aimed to investigate the role and potential mechanisms of key exosome-related genes in PD using transcriptome profiling at the single-cell level.

The current study cited GSE16134, GSE10334, GSE171213 datasets and 19,643 ERGs. Initially, differential expression analysis, three machine learning (ML) models, gene expression analysis and receiver operating characteristic (ROC) analysis were proceeded to identify core genes. Subsequently, a core gene-based artificial neural network (ANN) model was built to evaluate the predictive power of core genes for PD. Gene set enrichment analysis (GSEA) and immunoinfiltration analysis were conducted based on core genes. To pinpoint key cell types influencing the progression of periodontal at the single-cell level, a series of single-cell analyses covering pseudo-time series analysis were accomplished. The expression verification of core genes was performed through quantitative reverse transcription polymerase chain reaction (qRT-PCR).

CKAP2, IGLL5, MZB1, CXCL6, and AADACL2 served as core genes diagnosing PD. Four core gene were elevated in the PD group in addition to down-regulated AADACL2. The core gene-based-ANN model had AUC values of 0.909 in GSE16134 dataset, which exceeded AUC of each core gene, highlighting the accurately and credibly predictive performance of ANN model. GSEA revealed that ribosome was co-enriched by 5 core genes, manifesting the expression of these genes might be critical for protein structure or function. Immunoinfiltration analysis found that CKAP2, IGLL5, MZB1, and CXCL6 exhibited positive correlations with most discrepant immune cells/discrepant stromal cells, which were highly infiltrated in PD. B cells and T cells holding crucial parts in PD were identified as key cell types. Pseudo-time series analysis revealed that the expression of IGLL5 and MZB1 increased during T cell differentiation, increased and then decreased during B cell differentiation. The qRT-PCR proved the mRNA expression levels of CKAP2 and MZB1 were increased in the blood of PD patients compared to controls. But the mRNA expression levels of AADACL2 was decreased in the PD patients compared to controls. This is consistent with the trend in the amount of expression in the dataset.

CKAP2, IGLL5, MZB1, CXCL6 and AADACL2 were identified as core genes associated with exosomes, helping us to understand the role of these genes in PD.

Exosomes derived from primary chondrogenic stem/progenitor cells (CSPCs-EXOs) show promise in cartilage repair due to their immunomodulatory and regenerative properties. However, their specific therapeutic potential in osteoarthritis (OA), especially in modulating immune responses and enhancing chondrocyte function, requires further exploration. This study aims to clarify CSPCs-EXOs' effects on OA by investigating their role in chondrocyte proliferation, migration, inflammation inhibition, and cartilage regeneration.

A rat model of osteoarthritis was established using monosodium iodoacetate (MIA). CSPCs-EXOs were isolated and characterized before being administered to the OA rats. Comprehensive transcriptomic analysis was conducted to identify differentially expressed genes (DEGs) and signaling pathways influenced by CSPCs-EXOs. Histopathological evaluation of cartilage tissue, immunohistochemistry, and in vitro assays were performed to assess chondrocyte proliferation, migration, inflammation, and intracellular environmental changes.

CSPCs-EXOs treatment significantly reduced OA-induced cartilage damage, shown by improved histopathological features, increased chondrocyte proliferation, migration, and enhanced cartilage matrix integrity. CSPCs-EXOs uniquely modulated immune pathways and enhanced cellular repair, setting them apart from traditional treatments. Transcriptomic analysis revealed regulation of immune response, inflammation, oxidative stress, and DNA repair pathways. CSPCs-EXOs downregulated inflammatory cytokines (TNF, IL-17) and upregulated pathways for cellular proliferation, migration, and metabolism. They also altered splicing patterns of DNA repair enzymes, indicating a role in boosting repair mechanisms.

CSPCs-EXOs promote cartilage repair in osteoarthritis by modulating immune responses, inhibiting inflammation, and improving the intracellular environment. These findings emphasize their innovative therapeutic potential and offer key insights into their regenerative mechanisms, positioning CSPCs-EXOs as a promising strategy for OA treatment and a foundation for future clinical applications in cartilage tissue engineering and regenerative medicine.

Osteochondral lesions of the talus (OLT) are common ankle joint pathologies, often caused by traumatic or non-traumatic factors. Due to the anatomical characteristics and limited blood supply of the talus, the spontaneous healing capacity of OLT is poor, posing challenges for clinical treatment. Traditional treatments include conservative therapy and surgical interventions, but their efficacy is limited. In recent years, significant advancements in OLT treatment have been achieved with developments in biomaterials science, cell biology, and tissue engineering. This article summarizes the latest research progress in various treatment methods, including conservative treatment, bone marrow stimulation, chondrocyte transplantation, and osteochondral grafting, and evaluates the role of biological augmentation agents such as platelet-rich plasma (PRP) and concentrated bone marrow aspirate (CBMA) in promoting cartilage repair. Additionally, the application of biological scaffold technology offers new prospects for cartilage regeneration. Although emerging therapies show potential in clinical practice, further research is needed to evaluate their long-term efficacy, indications, and safety. This article aims to provide valuable references for clinicians, researchers, and policymakers, promoting the development and refinement of OLT treatment strategies.

As people's living standards continue to improve and human life span expectancy increases, the incidence and mortality rates of breast cancer are continuously rising. Early detection of breast cancer and targeted therapy for different breast cancer subtypes can significantly reduce the mortality rate and alleviate the suffering of patients. Exosomes are extracellular vesicles secreted by various cells in the body. They participate in physiological and pathological responses by releasing active substances and play an important role in regulating intercellular communication. In recent years, research on exosomes has gradually expanded, and their special membrane structure and targetable characteristics are being increasingly applied in various clinical studies. Mesenchymal stem cells (MSCs)-derived exosomes play an important role in regulating the progression of breast cancer. In this review, we summarize the current treatment methods for breast cancer, the connection between MSCs, exosomes, and breast cancer, as well as the application of exosomes derived from MSCs from different sources in cancer treatment. We highlight how the rational design of modified MSCs-derived exosomes (MSCs-Exos) delivery systems can overcome the uncertainties of stem cell therapy and overcome the clinical translation challenges of nanomaterials. This work aims to promote future research on the application of MSCs-Exos in breast cancer treatment.

Chronic pain affects nearly two billion people worldwide, surpassing heart disease, diabetes, and cancer in terms of economic costs. Lower back pain alone is the leading cause of years lived with disability worldwide. Despite limited treatment options, regenerative medicine, particularly extracellular vesicles (EVs) and exosomes, holds early promise for patients who have exhausted other treatment options. EVs, including exosomes, are nano-sized structures released by cells, facilitating cellular communication through bioactive molecule transfer, and offering potential regenerative properties to damaged tissues. Here, we review the potential of EVs and exosomes for the management of chronic pain.

In osteoarthritis, various exosomes, such as those derived from synovial mesenchymal stem cells, human placental cells, dental pulp stem cells, and bone marrow-derived mesenchymal stem cells (MSCs), demonstrate the ability to reduce inflammation, promote tissue repair, and alleviate pain in animal models. In intervertebral disc disease, Wharton's jelly MSC-derived EVs enhance cell viability and reduce inflammation. In addition, various forms of exosomes have been shown to reduce signs of inflammation in neurons and alleviate pain in neuropathic conditions in animal models. Although clinical applications of EVs and exosomes are still in the early clinical stages, they offer immense potential in the future management of chronic pain conditions. Clinical trials are ongoing to explore their therapeutic potential further, and with more research the potential applicability of EVs and exosomes will be fully understood.

Osteoarthritis (OA) induced microenvironmental alterations are a common and unavoidable phenomenon that greatly exacerbate the pathologic process of OA. Imbalances in the synthesis and degradation of cartilage extracellular matrix (ECM) have been reported to be associated with an adverse microenvironment. Stem cell therapy is a promising treatment for OA, and mesenchymal stem cells (MSCs) are the main cell sources for this therapy. With multispectral differentiation and immunomodulation, MSCs can effectively regulate the microenvironment of articular cartilage, ameliorate inflammation, promote regeneration of damaged cartilage, and ultimately alleviate OA symptoms. However, the efficacy of MSCs in the treatment of OA is greatly influenced by articular cavity microenvironments. This article reviews the five microenvironments of OA articular cavity, including inflammatory microenvironment, senescence microenvironment, hypoxic microenvironment, high glucose microenvironment and high lipid environment, focus on the positive and negative effects of OA microenvironments on the fate of MSCs. In this regard, we emphasize the mechanisms of the current use of MSCs in OA treatment, as well as its limitations and challenges.

Adipose-derived mesenchymal stem cells (ADSCs) have received significant attention in the field of cartilage tissue repair. Angelica sinensis polysaccharide (ASP) can enhance both the proliferation and differentiation of mesenchymal stem cells. Therefore, we intend to explore the effect of ASP on chondrogenic differentiation of ADSCs in vitro, and elucidate the underlying mechanisms.

ADSCs were treated with different concentrations of ASP to determine the optimal concentration. The chondrogenic differentiation of ADSCs was evaluated using Alcian blue staining, qRT-PCR, western blot, and IF staining. Transcriptome sequencing was performed to identify the expression profiles of ADSCs before and after ASP treatment, followed by bioinformatic analyses including differential expression analysis, enrichment analysis, and construction of PPI networks to identify differentially expressed genes (DEGs) associated with ASP and chondrogenic differentiation.

Surface markers of isolated rat-derived ADSCs were identified by CD44+CD90+CD45-CD106-, and exhibited the capacity for lipogenic, osteogenic, and chondrogenic differentiation. With increasing concentration of ASP treatment, there was an upregulation in the activity and acidic mucosubstance of ADSCs. The levels of Aggrecan, COL2A1, and Sox9 showed an increase in ADSCs after 28 days of 80 µg/ml ASP treatment. Transcriptome sequencing revealed that ASP-associated DEGs regulate extracellular matrix synthesis, immune response, inflammatory response, and cell cycle, and are involved in the NF-κB, AGE-RAGE, and calcium pathways. Moreover, Edn1, Frzb, Mdk, Nog, and Sulf1 are hub genes in DEGs. Notably, ASP upregulated MDK levels in ADSCs, while knockdown of MDK mitigated ASP-induced elevations in acidic mucosubstance, chondrogenic differentiation-related markers (Aggrecan, COL2A1, and Sox9), and the activity of the PI3K/AKT pathway.

ASP enhances the proliferation and chondrogenic differentiation of ADSCs by activating the MDK-mediated PI3K/AKT pathway.

Synovial mesenchymal stem cells (sMSCs) have great potential for cartilage repair, but their therapeutic design to avoid adverse effects associated with unknown factors remains a challenge. In addition, because long-term preservation is indispensable to maintain high quality levels until implantation, it is necessary to reduce their fluctuations. This study aimed to investigate the properties and feasibility of novel scaffold-free tissue-engineered constructs using serum-free media and to develop long-term preservation methods. sMSCs were cultured in serum-free media, seeded at high density in a monolayer, and finally developed as a sheet-like construct called "gMSC1". The properties of frozen gMSC1 (Fro-gMSC1) were compared with those of refrigerated gMSC1 (Ref-gMSC1) and then examined by their profile. Chondrogenic differentiation potential was analyzed by quantitative real-time polymerase chain reaction and quantification of glycosaminoglycan content. Xenografts into the cartilage defect model in rats were evaluated by histological staining. gMSC1 showed nearly similar properties independent of the preservation conditions. The animal experiment demonstrated that the defect could be filled with cartilage-like tissue with good integration to the adjacent tissue, suggesting that gMSC1 was formed and replaced the cartilage. Furthermore, several chondrogenesis-related factors were significantly secreted inside and outside gMSC1. Morphological analysis of Fro-gMSC1 revealed comparable quality levels to those of fresh gMSC1. Thus, if cryopreserved, gMSC1, with no complicated materials or processes, could have sustained cartilage repair capacity. gMSC1 is a prominent candidate in novel clinical practice for cartilage repair, allowing for large quantities to be manufactured at one time and preserved for a long term by freezing.

The online version contains supplementary material available at 10.1007/s10616-024-00637-y.

This study aimed to establish a combined histological assessment system of neo-cartilage outcomes and to evaluate variations in an established rat defect model treated with human juvenile cartilage-derived chondrocyte (JCC) sheets fabricated from various donors.

JCCs were isolated from the polydactylous digits of eight patients. Passage 2 (P2) JCC sheets from all donors were transplanted into nude rat chondral defects for 4 weeks (27 nude rats in total). Defect-only group served as control. Histological samples were stained for safranin O, collagen 1 (COL1), and collagen 2 (COL2). (1) All samples were scored, and correlation coefficients for each score were calculated. (2) Donors were divided into "more effective" and "less effective" groups based on these scores. Then, differences between each group in each category of modified O'Driscoll scoring were evaluated.

(1) Modified O'Driscoll scores were negatively correlated with %COL1 area, and positively correlated with %COL2 area and COL2/1 ratio. (2) Four of 8 donors exhibited significantly higher modified O'Driscoll scores and %COL2 areas. JCC donors were divided into two groups by average score values. Significant differences between the two groups were observed in modified O'Driscoll categories of "Nature of predominant tissue," "Reconstruction of subchondral bone," and "Safranin O staining."

The combined histological evaluation method is useful for detailed in vivo efficacy assessments of cartilage defect regeneration models. Variations in histological scores among juvenile cartilage-derived chondrocyte donors were correlated to the quality of regenerated cartilage hyaline structure and subchondral bone remodeling observed in the nude rat defect model.

Parkinson's disease (PD) is characterized by the pathological accumulation of α-synuclein, which has driven extensive research into the role of exosomes in disease mechanisms. Exosomes are nanoscale vesicles enriched with proteins, RNA, and lipids that facilitate critical intercellular communication processes. Recent studies have elucidated the role of exosomes in transmitting misfolded proteins among neurons, which significantly impacts the progression of PD. The presence of disease-associated exosomes in cerebrospinal fluid and blood highlights their substantial diagnostic potential for PD. Specifically, exosomes derived from the central nervous system (CNS) have emerged as promising biomarkers because of their ability to accurately reflect pathological states. Furthermore, the isolation of exosomes from distinct brain cell types allows the identification of precise biomarkers, increasing diagnostic specificity and accuracy. In addition to being useful for diagnostics, exosomes hold therapeutic promise given their ability to cross the blood-brain barrier (BBB) and selectively modulate their cargo. These findings suggest that these materials could be used as delivery systems for therapeutic drugs for the treatment of neurodegenerative diseases. This review comprehensively examines the multifaceted roles of exosomes in PD pathogenesis, diagnosis, and treatment. It also addresses the associated clinical challenges and underscores the urgent need for further research and development to fully leverage exosome-based strategies in PD management.

Joint diseases greatly impact the daily lives and occupational functioning of patients globally. However, conventional treatments for joint diseases have several limitations, such as unsatisfatory efficacy and side effects, necessitating the exploration of more efficacious therapeutic strategies. Mesenchymal stem cell (MSC)-derived EVs (MSC-EVs) have demonstrated high therapeutic efficacyin tissue repair and regeneration, with low immunogenicity and tumorigenicity. Recent studies have reported that EVs-based therapy has considerable therapeutic effects against joint diseases, including osteoarthritis, tendon and ligament injuries, femoral head osteonecrosis, and rheumatoid arthritis. Herein, we review the therapeutic potential of various types of MSC-EVs in the aforementioned joint diseases, summarise the mechanisms underlying specific biological effects of MSC-EVs, and discuss future prospects for basic research on MSC-EV-based therapeutic modalities and their clinical translation. In general, this review provides an in-depth understanding of the therapeutic effects of MSC-EVs in joint diseases, as well as the underlying mechanisms, which may be beneficial to the clinical translation of MSC-EV-based treatment. The translational potential of this article: MSC-EV-based cell-free therapy can effectively promote regeneration and tissue repair. When used to treat joint diseases, MSC-EVs have demonstrated desirable therapeutic effects in preclinical research. This review may supplement further research on MSC-EV-based treatment of joint diseases and its clinical translation.

This study investigated the therapeutic effects of exosomes derived from human-induced pluripotent stem cell (hiPSC)-derived retinal organoids (ROs) on corneal epithelial wound healing. Exosomes were isolated from the culture medium of the hiPSC-derived ROs (Exo-ROs) using ultracentrifugation, and then they were characterized by a nanoparticle tracking analysis and transmission electron microscopy. In a murine model of corneal epithelial wounds, these exosomes were topically applied to evaluate their healing efficacy. The results demonstrated that the exosome-treated eyes showed significantly enhanced wound closures compared with the controls at 24 h post-injury. The 5-ethyl-2'-deoxyuridine assay and quantitative reverse transcription polymerase chain reaction revealed a substantial increase in cell proliferation and a decrease in inflammatory marker contents in the exosome-treated group. The RNA sequencing and exosomal microRNA analysis revealed that the Exo-RO treatment targeted various pathways related to inflammation and cell proliferation, including the PI3K-Akt, TNF, MAPK, and IL-17 signaling pathways. Moreover, the upregulation of genes related to retinoic acid and eicosanoid metabolism may have enhanced corneal epithelial healing in the eyes treated with the Exo-ROs. These findings suggest that hiPSC-derived RO exosomes could be novel therapeutic agents for promoting corneal epithelial wound healing.

Temporomandibular joint osteoarthritis (TMJOA) is a degenerative ailment that causes slow cartilage degeneration, aberrant bone remodeling, and persistent discomfort, leading to a considerable reduction in the patient's life quality. Current treatment options for TMJOA have limited efficacy. This investigation aimed to explore a potential strategy for halting or reversing the progression of TMJOA through the utilization of exosomes (EXOs) derived from urine-derived stem cells (USCs). The USC-EXOs were obtained through microfiltration and ultrafiltration techniques, followed by their characterization using particle size analysis, electron microscopy, and immunoblotting. Subsequently, an in vivo model of TMJOA induced by mechanical force was established. To assess the changes in the cartilage of TMJOA treated with USC-EXOs, we performed histology analysis using hematoxylin-eosin staining, immunohistochemistry, and histological scoring. Our findings indicate that the utilization of USC-EXOs yields substantial reductions in TMJOA, while concurrently enhancing the structural integrity and smoothness of the compromised condylar cartilage surface. Additionally, USC-EXOs exhibit inhibitory effects on osteoclastogenic activity within the subchondral bone layer of the condylar cartilage, as well as attenuated apoptosis in the rat TMJ in response to mechanical injury. In conclusion, USC-EXOs hold considerable promise as a potential therapeutic intervention for TMJOA.

Osteoarthritis (OA) is a prevalent degenerative disease that afflicts more than 250 million people worldwide, impairing their mobility and quality of life. However, conventional drug therapy is palliative. Exosomes (Exo), although with the potential to fundamentally repair cartilage, face challenges in their efficient enrichment and delivery. In this study, we developed magnetic polysaccharide hydrogel particles as microcarriers for synergistic therapy of OA. The microcarriers were composed of modified natural polysaccharides, hyaluronic acid (HAMA), and chondroitin sulfate (CSMA), and were generated from microfluidic electrospray in combination with a cryogelation process. Magnetic nanoparticles with spiny structures capable of capturing stem cell Exo were encapsulated within the microcarriers together with an anti-inflammatory drug diclofenac sodium (DS). The released DS and Exo from the microcarriers had a synergistic effect in alleviating the OA symptoms and promoting cartilage repair. The in vitro and in vivo results demonstrated the excellent performance of the microcarrier for OA treatment. We believe this work has potential for Exo therapy of OA and other related diseases.

In knee osteoarthritis (KOA), treatments involving knee injections of bone marrow-derived mesenchymal stem cells (BM-MSC), adipose tissue-derived mesenchymal stem cells (AD-MSC), or umbilical cord-derived mesenchymal stem cells (UC-MSC) have shown promise in alleviating symptoms. However, which types of mesenchymal stem cells (MSCs) have the best therapeutic outcomes remain uncertain.

We systematically searched PubMed, OVID, Web of Science, and the Cochrane Library until January 1, 2024. The study evaluated five endpoints: Visual Analog Score (VAS) for Pain, Range of Motion (ROM), Whole-Organ Magnetic Resonance Imaging Score (WORMS), Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and adverse events (ADs). Standard meta-analysis and network meta-analysis were performed using Stata 16.0.

Fifteen studies involving 585 patients were included in the meta-analysis. Standard meta-analysis revealed significant improvements with MSCs in VAS score (P < 0.001), knee ROM (P < 0.001), and WOMAC (P < 0.016) compared to traditional therapy. In the network meta-analysis, autologous MSCs significantly improved VAS score [SMD = 2.94, 95% CI (1.90, 4.56)] and knee ROM [SMD = 0.26, 95% CI (0.08, 0.82)] compared to traditional therapy. Similarly, BM-MSC significantly improved VAS score [SMD = 0.31, 95% CI (0.11, 0.91)] and knee ROM [SMD = 0.26, 95% CI (0.08, 0.82)] compared to hyaluronic acid. However, compared with traditional therapy, autologous or allogeneic MSCs were associated with more adverse reactions [SMD = 0.11, 95% CI (0.02, 0.59)], [SMD = 0.13, 95% CI (0.002, 0.72)]. Based on the surface under the cumulative ranking results, autologous BM-MSC showed the most improvement in ROM and pain relief in KOA patients, UC-MSC (SUCRA 94.1%) were most effective for positive WORMS, and AD-MSC (SUCRA 70.6%) were most effective for WOMAC-positive patients.

MSCs transplantation effectively treats KOA patients, with autologous BM-MSC potentially offering more excellent benefits.

Osteoarthritis (OA) is a degenerative joint disorder characterized by the progressive deterioration of articular cartilage driven and sustained by catabolic and inflammatory processes that lead to pain and functional impairment. Adipose-derived stem cells (ASCs) have emerged as a promising therapeutic strategy for OA due to their regenerative potential, which mainly relies on the adaptive release of paracrine molecules that are soluble or encapsulated in extracellular vesicles (EVs). The biological effects of EVs specifically depend on their cargo; in particular, microRNAs (miRNAs) can specifically modulate target cell function through gene expression regulation. This study aimed to investigate the impact of collection site (abdominal vs. peri-trochanteric adipose tissue) and collection method (surgical excision vs. lipoaspiration) on the miRNAs profile in ASC-derived EVs and their potential implications for OA therapy. EV-miRNA cargo profiles from ASCs of different origins were compared. An extensive bioinformatics search through experimentally validated and OA-related targets, pathways, and tissues was conducted. Several miRNAs involved in the restoration of cartilage homeostasis and in immunomodulation were identified in all ASC types. However, EV-miRNA expression profiles were affected by both the tissue-harvesting site and procedure, leading to peculiar characteristics for each type. Our results suggest that adipose-tissue-harvesting techniques and the anatomical site of origin influence the therapeutic efficacy of ASC-EVs for tissue-specific regenerative therapies in OA, which warrants further investigation.

Targeted drug delivery and the reduction of off-target effects are crucial for the promising clinical application of nucleic acid drugs. To address this challenge, a new approach for treating osteoarthritis (OA) that accurately delivers antisense oligonucleotides (ASO) targeting matrix metalloproteinase-13 (ASO-MMP13) to chondrocytes, is developed. Small extracellular vesicles (exos) are ligated with chondrocyte affinity peptide (CAP) using Sortase A and subsequently incubated with cholesterol-modified ASO-MMP13 to construct a chondrocyte-targeted drug delivery exo (CAP-exoASO). Compared with exos without CAP (ExoASO), CAP-exoASOs attenuate IL-1β-induced chondrocyte damage and prolong the retention time of ASO-MMP13 in the joint without distribution in major organs following intra-articular injection. Notably, CAP-exoASOs decrease MMP13 expression (P < 0.001) and upregulate COL2A1 expression (P = 0.006), resulting in reorganization of the cartilage matrix and alleviation of progression in the OA model. Furthermore, the Osteoarthritis Research Society International (OARSI) score of articular cartilage tissues treated with CAP-exoASO is comparable with that of healthy rats (P = 0.148). A mechanistic study demonstrates that CAP-exoASO may reduce inflammation by suppressing the IL-17 and TNF signaling pathways. Based on the targeted delivery effect, CAP-exoASOs successfully accomplish cartilage repair and have considerable potential for development as a promising therapeutic modality for satisfactory OA therapy.

Extracellular vesicles (EVs) derived from human adipose-derived mesenchymal stem cells (hADSCs) have shown great therapeutic potential in plastic and reconstructive surgery. However, the limited production and functional molecule loading of EVs hinder their clinical translation. Traditional two-dimensional culture of hADSCs results in stemness loss and cellular senescence, which is unfavorable for the production and functional molecule loading of EVs. Recent advances in regenerative medicine advocate for the use of three-dimensional culture of hADSCs to produce EVs, as it more accurately simulates their physiological state. Moreover, the successful application of EVs in tissue engineering relies on the targeted delivery of EVs to cells within biomaterial scaffolds.

The hADSCs spheroids and hADSCs gelatin methacrylate (GelMA) microspheres are utilized to produce three-dimensional cultured EVs, corresponding to hADSCs spheroids-EVs and hADSCs microspheres-EVs respectively. hADSCs spheroids-EVs demonstrate excellent production and functional molecule loading compared with hADSCs microspheres-EVs. The upregulation of eight miRNAs (i.e. hsa-miR-486-5p, hsa-miR-423-5p, hsa-miR-92a-3p, hsa-miR-122-5p, hsa-miR-223-3p, hsa-miR-320a, hsa-miR-126-3p, and hsa-miR-25-3p) and the downregulation of hsa-miR-146b-5p within hADSCs spheroids-EVs show the potential of improving the fate of remaining ear chondrocytes and promoting cartilage formation probably through integrated regulatory mechanisms. Additionally, a quick and innovative pipeline is developed for isolating chondrocyte homing peptide-modified EVs (CHP-EVs) from three-dimensional dynamic cultures of hADSCs spheroids. CHP-EVs are produced by genetically fusing a CHP at the N-terminus of the exosomal surface protein LAMP2B. The CHP + LAMP2B-transfected hADSCs spheroids were cultured with wave motion to promote the secretion of CHP-EVs. A harvesting method is used to enable the time-dependent collection of CHP-EVs. The pipeline is easy to set up and quick to use for the isolation of CHP-EVs. Compared with nontagged EVs, CHP-EVs penetrate the biomaterial scaffolds and specifically deliver the therapeutic miRNAs to the remaining ear chondrocytes. Functionally, CHP-EVs show a major effect on promoting cell proliferation, reducing cell apoptosis and enhancing cartilage formation in remaining ear chondrocytes in the M1 macrophage-infiltrated microenvironment.

In summary, an innovative pipeline is developed to obtain CHP-EVs from three-dimensional dynamic culture of hADSCs spheroids. This pipeline can be customized to increase EVs production and functional molecule loading, which meets the requirements for regulating remaining ear chondrocyte fate in the M1 macrophage-infiltrated microenvironment.

To date, different strategies have been used for co-transplantation of cell-loaded biomaterials for bone tissue regeneration. This study aimed to investigate the osteogenic properties of adipose-derived-mesenchymal stem cell (AD-MSC) sheets combined with nanofibrous poly-caprolactone (PCL) mat and Gelfoam in rats with calvarial bone defect.

Calvarial critical-size defects were induced in male rats. Animals were classified into Control, Gelfoam, Gelfoam/PCL nanofiber, Gelfoam/AD-MSC sheet, and Gelfoam/PCL nanofiber/AD-MSC sheet groups. After 3 months, rats were sacrificed and the regeneration rate was evaluated.

Almost all groups showed bone regeneration properties, but the volume of newly formed bone was higher in groups that received Gelfoam/AD-MSC and Gelfoam/PCL nanofiber/AD-MSC sheets (P < 0.05). The application of Gelfoam/PCL nanofiber/AD-MSC sheets not only increased bone thickness, bone volume/total bone volume (BV/TV) ratio, strong Hounsfield Unit (HU), but also led to the formation of ossified connective tissue with wrinkled patterns.

The current study indicated that the Gelfoam/PCL nanofiber/AD-MSC sheet provides a suitable platform for effective osteogenesis in calvarial bone defects.

Exosomes derived from bone marrow mesenchymal stem cells (BMSC-Exos) may modulate the M1/M2 polarization of macrophages during osteoarthritis (OA). However, the underlying mechanisms of BMSC-Exos in this process still need to be elucidated. In this study, we explored the role of BMSC-Exos in the polarization of macrophages in vitro and the OA rats in vivo.

The effects of BMSC-Exos on RAW264.7 cells were determined, including the production of reactive oxygen species (ROS) and the protein expression of Akt, PINK1, and Parkin. We prepared an OA model by resecting the anterior cruciate ligament and medial meniscus of Sprague-Dawley (SD) rats. Hematoxylin-eosin (H&E) and safranin O-fast green staining, immunohistochemistry and immunofluorescence analyses, and the examination of interleukin 6 (IL-6), interleukin 1β (IL-1β), tumor necrosis factor alpha (TNF-α), and interleukin 10 (IL-10) were performed to assess changes in cartilage and synovium.

BMSC-Exos inhibited mitochondrial membrane damage, ROS production, and the protein expression of PINK1 and Parkin. Akt phosphorylation was downregulated under lipopolysaccharide (LPS) induction but significantly recovered after treatment with BMSC-Exos. BMSC-Exos alleviated cartilage damage, inhibited M1 polarization, and promoted M2 polarization in the synovium in OA rats. The expression of PINK1 and Parkin in the synovium and the levels of IL-6, IL-1β, and TNF-α in the serum decreased, but the level of IL-10 increased when BMSC-Exos were used in OA rats.

BMSC-Exos ameliorate OA development by regulating synovial macrophage polarization, and one of the underlying mechanisms may be through inhibiting PINK1/Parkin signaling.

Pain is the major symptom of osteoarthritis (OA) and is an important factor in strategies to manage this disease. However, the current standard of care does not provide satisfactory pain relief for many patients. The pathophysiology of OA is complex, and its presentation as a clinical syndrome is associated with the pathologies of multiple joint tissues. Treatment options are generally classified as pharmacologic, nonpharmacologic, surgical, and complementary and/or alternative, typically used in combination to achieve optimal results. The goals of treatment are the alleviation of symptoms and improvement in functional status. Several studies are exploring various directions for OA pain management, including tissue regeneration techniques, personalized medicine, and targeted drug therapies. The aim of the present narrative review is to extensively describe all the treatments available in the current practice, further describing the most important innovative therapies. Advancements in understanding the molecular and genetic aspects of osteoarthritis may lead to more effective and tailored treatment approaches in the future.

To explore the protective effect of human urine-derived stem cell exosomes (hUSC-Exos) on radiation-induced salivary gland (SG) injuries in Sprague Dawley rats.

Fresh adult urine was collected, and primary hUSCs were isolated and identified. The hUSCs were hypoxia-pretreated with 1% oxygen for 24 h and then transferred to a normoxic culture environment for 24 h. The hUSC-Exos were collected and identified for exosomes. A radiation-induced injury model was established in the rats, and exosomes were introduced by local injection in the SG and tail vein. The submandibular gland was excised for morphological observation 1 week later. Immunohistochemical detection of the glandular tissue was conducted by α-smooth muscle actin (a-SMA), stem cell growth factor receptor (c-Kit) staining, and periodic acid-Schiff staining. Qualitative polymerase chain reaction and western blot analysis were adopted to detect the gene and protein expression of Wnt3a, GSK3β, and Axin.

In both the normoxic and hypoxic hUSC-Exo groups, microvesicular structures with bilayer membranes of approximately 80 nm in diameter were detected, and the expressions of CD9 and CD63 were detected by nanoflow cytometry. Compared with the control group, in the radiation-induced injury model group, the expression of a-SMA was significantly higher, the expression of c-Kit was significantly lower, and the expressions of Wnt3a, GSK3β, and Axin were significantly upregulated; the differences were statistically significant (p < 0.05). Compared with the model group, in the normoxic and hypoxic hUSC-Exo groups, the expression of a-SMA was significantly decreased, the expression of c-Kit was significantly increased, and the expressions of Wnt3a, GSK3β, and Axin were significantly upregulated; the differences were statistically significant (p < 0.05).

Hypoxia-pretreated hUSC-Exos could repair radiation-induced SG injuries by activating the Wnt3a/GSK3β pathway to suppress the expressions of a-SMA and c-Kit.

Cartilage defects in the knee are often associated with the progression of degenerative osteoarthritis (OA), and cartilage repair is a useful strategy for managing this disease. However, cartilage repair is challenging because of the unique environment within the tissue. Recently, stem cell-based therapies have shed new light on this issue. In this study, we prepared exosomes (EXOs) from cartilage stem/progenitor cells (CSPCs) and found that treatment with EXOs increased the viability, migration, and proliferation of cultured primary chondrocytes. In a subacute OA rat model, the application of EXOs facilitated cartilage regeneration as evidenced by histological staining. Exosomal protein analysis together with bioinformatics suggested that cyclin-dependent kinase 9 (CDK9) is a key factor for chondrocyte growth and migration. Functional studies confirmed this prediction, that is, inhibiting CDK9 reduced the beneficial effects induced by EXOs in primary chondrocytes; while overexpression of CDK9 recapitulated the EXOs-induced phenotypes. RNA-Seq data showed that a set of genes involved in cell growth and migration were up-regulated by EXOs in chondrocytes. These changes could be partially reproduced by CDK9 overexpression. Overall, our data suggest that EXOs derived from primary CSPCs hold great therapeutic potential for treating cartilage defect-associated disorders such as degenerative OA, and that CDK9 is a key factor in this process.

Periodontitis is a prevalent oral ailment that harms both hard and soft tissues of the periodontium, leading to loosening and eventual removal of the teeth. Current clinical treatments have limitations in achieving complete periodontal tissue regeneration. Mesenchymal stem cells (MSCs) have garnered attention due to their unique characteristics and potential as a promising new therapy for periodontitis. Research suggests that the role of MSCs in regenerative medicine primarily occurs through the paracrine pathway, involving the emission of particles encased by lipids called extracellular vesicles (EVs) abundant in bioactive compounds. These EVs play a vital function in controlling the activities of periodontal tissues and immune system cells, and by influencing the immediate surrounding, thus fostering the healing of periodontal damage and renewal of tissues. EVs obtained from MSCs (MSC-EVs), in the form of a cell-free treatment, offer advantages in terms of stability, reduced immune rejection, and ethical considerations, elevating their potential as a hopeful choice for broad clinical applications. This concise overview highlights the mechanisms of MSC-EVs and the possibilities they hold in clinical application for periodontal regeneration.

Bioprinting, using "bio-inks" consisting of living cells, supporting structures, and biological motifs to create customized constructs, is an emerging technique that aims to overcome the challenges of cartilaginous reconstruction of head and neck structures. Several living cell lines and culturing methods have been explored as bio-inks with varying efficacy. Coculture of primary chondrocytes and stem cells (SCs) is one technique well established for degenerative joint disease treatment, with potential for use in expanding chondrocyte populations for bio-inks. This study aimed to evaluate the techniques for coculture of primary chondrocytes and SCs for head and neck cartilage regeneration.

A literature review was performed through OVID/Web of Science/MEDLINE/BIOSIS Previews/Embase. Studies reporting on chondrocytes and SCs in conjunction with coculture or cartilage regeneration were included. Studies not reporting on findings from chondrocytes/SCs of the head and neck were excluded. Extracted data included cell sources, coculture ratios, and histological, biochemical, and clinical outcomes.

Fifteen studies met inclusion criteria. Auricular cartilage was the most common chondrocyte source (n = 10), then nasal septum (n = 5), articular (n = 1), and tracheal cartilage (n = 1). Bone marrow was the most common SC source (n = 9) then adipose tissue (n = 7). Techniques varied, with coculture ratios ranging from 1:1 to 1:10. All studies reported coculture to be superior to SC monoculture by all outcomes. Most studies reported superiority or equivalence of coculture to chondrocyte monoculture by all outcomes. When comparing clinical outcomes, coculture constructs were equivalent to chondrocyte monoculture in diameter and equivalent or inferior in wet weight and height.

Coculture of primary chondrocytes and SCs is a promising technique for expanding chondrocyte populations, with at least equivalence to chondrocyte monoculture and superior to SC monoculture when seeded at the same chondrocyte densities. However, there remains a lack of consensus regarding the optimal cell sources and coculture ratios.

Pulmonary arterial hypertension (PAH) is characterized by extensive pulmonary arterial remodelling. Although mesenchymal stem cell (MSC)-derived exosomes provide protective effects in PAH, MSCs exhibit limited senescence during in vitro expansion compared with the induced pluripotent stem cells (iPSCs). Moreover, the exact mechanism is not known.

In this study, we used murine iPSCs generated from mouse embryonic fibroblasts with triple factor (Oct4, Klf4, and Sox2) transduction to determine the efficacy and action mechanism of iPSC-derived exosomes (iPSC-Exo) in attenuating PAH in rats with monocrotaline (MCT)-induced pulmonary hypertension. Both early and late iPSC-Exo treatment effectively prevented the wall thickening and muscularization of pulmonary arterioles, improved the right ventricular systolic pressure, and alleviated the right ventricular hypertrophy in MCT-induced PAH rats. Pulmonary artery smooth muscle cells (PASMC) derived from MCT-treated rats (MCT-PASMC) developed more proliferative and pro-migratory phenotypes, which were attenuated by the iPSC-Exo treatment. Moreover, the proliferation and migration of MCT-PASMC were reduced by iPSC-Exo with suppression of PCNA, cyclin D1, MMP-1, and MMP-10, which are mediated via the HIF-1α and P21-activated kinase 1/AKT/Runx2 pathways.

IPSC-Exo are effective at reversing pulmonary hypertension by reducing pulmonary vascular remodelling and may provide an iPSC-free therapy for the treatment of PAH.