There is currently increasing focus on aging-related diseases. Osteoporosis is a common disease the incidence of which increases with age. In older patients with osteoporosis, bone marrow mesenchymal stem cells (BMMSCs) have a decreased capacity for osteogenesis and an increased capacity for adipogenesis, causing excessive accumulation of adipose tissue in the bone marrow. Therefore, means of reducing bone marrow adiposity may have therapeutic potential for osteoporosis. Apoptotic vesicles (apoVs) participate in a wide range of physiological processes and have been shown to have therapeutic effects in a variety of diseases. The principal objective of this study was to examine the special properties and regulatory mechanisms of BMMSC-derived apoVs in the treatment of bone marrow adiposity.

The results showed that apoVs could decrease bone marrow adiposity in osteoporotic mice and prevent adipogenic differentiation of MSCs by activating the Wnt/β-catenin pathway.

New apoV-based therapies have potential for the treatment of bone marrow adiposity in patients with aging-related osteoporosis and may be further applicable to the treatment of obesity and aging-related diseases.

Engineered extracellular vesicles (EVs), which are EVs modified to enhance certain biological properties, offer a promising therapeutic strategy for the treatment of skin defects. Conventional nanomaterials often encounter clinical translation challenges due to potential toxicity and limited targeting. Engineered EVs, utilizing inherent biocompatibility and effective physiological barrier traversal, can ameliorate the limitations of conventional EV therapies to some extent, including detection, isolation, purification, and therapeutic validation. Recent advances in EV engineering, such as genetic modification of production cells to control cargo, surface engineering for targeted delivery, and pre-treatment of parental cells to optimize production and bioactivity, have improved therapeutic efficacy in laboratory studies through enhanced targeting, prolonged retention time, and increased yield. Many studies have suggested the potential ability of engineered EVs to treat a variety of skin defects, including diabetic wounds, burns, and hypertrophic scars, providing a promising avenue for their clinical translation in this area. This paper reviews the therapeutic potential of engineered EVs in skin regeneration, highlighting their role in promoting cell migration and angiogenesis, modulating inflammation and reducing scar formation during wound healing. In addition, given the investment in this rapidly evolving field and the growing clinical trial activity, this review also explores recent global advances and provides an outlook on future application opportunities for EVs in the treatment of skin defects.

Extracellular vesicles (EVs), a diverse population of bilayer lipid-membrane vesicles secreted by cells, have emerged as ideal drug carriers due to their efficient cellular uptake and targeted delivery capabilities. Advancements in medical and bioengineering collaborations have enabled EVs to be engineered for specific marker expression or therapeutic cargo transport, positioning them as a promising modality for treating cancer, neurological disorders, cardiovascular diseases, and beyond. EV-based drug delivery strategies offer distinct advantages, including facilitation of intercellular communication and immune modulation, high biocompatibility and stability, the ability to traverse the blood-brain barrier, and potential synergistic interactions with encapsulated therapeutics to enhance efficacy. This review explores EV isolation and scalable production, emphasizing cost-effective and reproducible manufacturing strategies, cargo-loading methodologies, and therapeutic applications. Additionally, the current landscape of EV-based targeted drug delivery, clinical translation prospects, and prevailing challenges are examined to provide a comprehensive perspective on their potential in drug delivery systems.

Acute lung injury (ALI) which is caused by Staphylococcus aureus (SA), is a serious lung disease that threatens human health. Although some current treatments are effective in alleviating ALI, they still have a significant mortality rate. At present, adipose-derived mesenchymal stem cells (ADSCs)-derived extracellular vesicles (EVs) have been investigated for the treatment of various diseases. Here, we examined the role of ADSCs-derived EVs in regulating apoptosis and inflammation during ALI.

We showed that ADSCs and ADSCs-derived EVs supplementation could improve lung injury, restore mitochondrial function, and inhibit inflammation and apoptosis in ALI mice. Furthermore, miR-320a was present in EVs derived from ADSCs, and it can be transferred into lung tissue. In vitro, Casitas B-lineage lymphoma (CBL) expression was inhibited by miR-320a mimics. Finally, we found that miR-320a alleviated mitochondrial damage, inflammation, and apoptosis via the CBL/AMPK/JNK pathway.

In conclusion, EVs from ADSCs could alleviate ALI via the CBL/AMPK signaling pathway. Therefore, the purpose of our study was to investigate the application of ADSC-derived EVs in mitigating ALI by modulating metabolic processes.

Bone healing is a well-orchestrated process involving various bone cells and signaling pathways, where disruptions can result in delayed or incomplete healing. MicroRNAs (miRNAs) are small non-coding RNAs capable of influencing various cellular processes, including bone remodeling. Due to their biological relevance and stable presence in biofluids, miRNAs may serve as candidates for diagnosis and prognosis of delayed bone healing. The aim of the study was to investigate changes in miRNAs circulating in the blood during the healing of rat calvaria defects as biomarkers of successful bone regeneration.

Standardized calvaria defects were created in 36 Wistar rats with a trephine drill and treated with collagen hydroxyapatite (CHA) scaffolds. The treatment groups included CHA scaffolds only, CHA scaffolds containing a plasmid coding for bone morphogenetic protein 2 (BMP2) and miR-590-5p, CHA scaffolds containing mesenchymal stromal cell-derived extracellular vesicles, and empty defects as a control group. After 1, 4 and 8 weeks of healing, the animals were evaluated by microcomputed tomography (microCT), as well as subjected to histological analyses. Blood was sampled from the tail vein prior to surgeries and after 1, 4, and 8 weeks of healing. miRNAs circulating in the plasma were determined using next-generation sequencing.

Variability of bone regeneration within the four groups was unexpectedly high and did not result in significant differences between the groups, as indicated by the microCT and histological analyses of the newly formed bone tissue. However, irrespective of the treatment group and regenerative activity, we identified miRNAs with distinct expression patterns of up- and downregulation at different time points. Furthermore, rats with high and low regenerative activity were characterized by distinct circulating miRNA profiles. miR-133-3p was identified as the top upregulated miRNA and miR-375-3p was identified as the top downregulated miRNA in animals exhibiting strong regeneration over all time points evaluated.

Our study indicates that regardless of the treatment group, success or lack of bone regeneration is associated with a distinct expression pattern of circulating microRNAs. Further research is needed to determine whether their levels in the blood can be used as predictive factors of successful bone regeneration.

Adding metal ions is a promising strategy to enhance the biological performance of titanium implants. In this study, we aimed to explore the effects of yttrium on the osseointegration of titanium implants. First, a series of yttrium-doped titanium surfaces were fabricated via microarc oxidation (MAO) by incorporating yttrium acetate into the electrolyte, and then the surface characteristics of different substrates were evaluated. Subsequently, the cellular behaviors of different coatings were assessed, and the osteointegration effects were examined using a rat model. Finally, high-throughput sequencing was employed to elucidate the underlying mechanisms of the yttrium-doped MAO coatings. As the results indicated, the proportion of yttrium in the coatings increased as the concentration of yttrium acetate improved. Surface characterization revealed that the yttrium-doped MAO coatings exhibited a homogeneous porous morphology, with comparable roughness and wettability to those of the undoped MAO coating, while the morphology became inconsistent when the yttrium acetate concentration reached 30 mM. The in vitro assays demonstrated that the addition of yttrium notably improved the cell adhesion, spreading, proliferation, and osteogenic differentiation of MAO coatings when doped with a low proportion, accompanied by enhanced osseointegration according to the in vivo experiments. Further exploration revealed a significant enrichment of osseointegration-related signaling factors and the activation of BMP/Smad signaling in the effects of yttrium-doped titanium coatings, which was attributed to the excessive accumulation of phosphorylated Smad1/5/9 in the nucleus. In summary, our work demonstrates that the use of MAO coatings doped with a low proportion of yttrium can enhance the osseointegration of titanium implants, providing an efficient strategy to optimize titanium implant performance.

Exosomes are double-membrane vesicular nanoparticles in the category of extracellular vesicles, ranging in size from 30 to 150 nm, and are released from cells through a specific multi-step exocytosis process. Exosomes have emerged as promising tools for tissue repair due to their ability to transfer bioactive molecules that promote cell proliferation, differentiation, and tissue regeneration. However, the therapeutic application of exosomes is hindered by their rapid clearance from the body and limited retention at the injury site. To overcome these challenges, hydrogels, known for their high biocompatibility and porous structure, have been explored as carriers for exosomes. Hydrogels can provide a controlled release mechanism, prolonging the retention time of exosomes at targeted tissues, thus enhancing their therapeutic efficacy. This review focuses on the combination of different exosomes with hydrogels in the context of tissue repair. We first introduce the sources and functions of exosomes, particularly those from mesenchymal stem cells, and their roles in regenerative medicine. We then examine various types of hydrogels, highlighting their ability to load and release exosomes. Several strategies for encapsulating exosomes in hydrogels are discussed, including the impact of hydrogel composition and structure on exosome delivery efficiency. Finally, we review the applications of exosomes-loaded hydrogels in the repair of different tissues, such as skin, bone, cartilage, and nerve, and explore the challenges and future directions in this field. The combination of exosomes with hydrogels offers significant promise for advancing tissue repair strategies and regenerative therapies.

Adipose-derived mesenchymal stem cells (ADSCs) exosomes (AD-Exos) are a novel and promising therapeutic approach for skin damage repair. This investigation seeks to assess the potential clinical utility of miR-141-3p found in AD-exos for expediting wound healing.

ADSCs were isolated from the wounded patients' tissue and validated via flow cytometry, and the mineralization and adipogenic capabilities of ADSCs were assessed respectively. Additionally, exosomes were isolated and identified. miR-141-3p and HDAC6.protein level were tested. Full-thickness wound models were created on the backs of mice, HE staining, ELISA, and immunohistochemistry were used to assess the influences of AD-exos on wound healing, inflammation, and new blood vessel formation Western blot was to assess the related-protein levels of JNK/ERK pathway. AQ1 Meanwhile, Dual-Luciferase assay confirmed the relationship between miR-141-3p and HDAC6.

The isolated cells highly express surface markers of mesenchymal stem cells and possess the potential for multidirectional differentiation, confirming them to be ADSCs. And miR-141-3p down-regulated but HDAC6 up-regulated in the serum and AD-exos of wounded patients. miR-141-3p could negatively modulate HDAC6. The miR-141-3p in AD-exos accelerated wound healing in mice, mitigated inflammatory responses and scarring in the injured skin tissue, and promoted angiogenesis, moreover, AD-exos could diminish the phosphorylation of JNK and ERK, while HDAC6 overexpressed could weaken these impacts.

miR-141-3p in AD-exos can target down regulate HDAC6 expression and inhibit JNK/ERK signaling pathway activation, thereby reducing wound inflammation and promoting angiogenesis and wound healing in mice.

Exosomes, cell-derived vesicles produced by cells, are fascinating and drawing growing interest in biomedical exploration due to their exceptional properties. There is intriguing evidence that exosomes are involved in major biological processes, including diseases and regeneration. Exosomes from mesenchymal stem cells (MSCs) have shown promising outcomes in regenerative medicine. Numerous studies suggest that exosomes have several advantages over conventional synthetic nanocarriers, opening novel frontiers for innovative drug delivery. Regenerative medicine has demonstrated the profound therapeutic outcomes of engineered or loaded exosomes from MSCs. Different methods are being used to modify or/load exosomes. These exosomes can improve cell signaling pathways for bone and cartilage diseases, liver diseases, nerve tissues, kidney diseases, skin tissue, and cardiovascular diseases. Despite extensive research, clinical translation of these exosomes remains a challenge. The optimization of cargo loading methods, efficiency, physiological stability, and the isolation and characterization of exosomes present some challenges. The upcoming examination should include the development of large-scale, quality-controllable production approaches, the modification of drug loading approaches, and numerous in vivo investigations and clinical trials. Here, we provided an informative overview of the extracellular vesicles and modification/loading methods of exosomes. We discuss the last exosome research on regeneration disorders, highlighting the therapeutic applications of MSCs-derived exosomes. We also highlight future directions and challenges, underscoring the significance of addressing the main questions in the field.

Exosomes are a subset of extracellular vesicles (EVs) secreted by nearly all cell types and have emerged as a novel mechanism for intercellular communication within the central nervous system (CNS). These vesicles facilitate the transport of proteins, nucleic acids, lipids, and metabolites between neurons and glial cells, playing a pivotal role in CNS development and the maintenance of homeostasis. Current evidence indicates that exosomes from CNS cells may function as either inhibitors or enhancers in the onset and progression of neurological disorders. Furthermore, exosomes have been found to transport disease-related molecules across the blood-brain barrier, enabling their detection in peripheral blood. This distinctive property positions exosomes as promising diagnostic biomarkers for neurological conditions. Additionally, a growing body of research suggests that exosomes derived from mesenchymal stem cells exhibit reparative effects in the context of neurological disorders. This review provides a concise overview of the functions of exosomes in both physiological and pathological states, with particular emphasis on their emerging roles as potential diagnostic biomarkers and therapeutic agents in the treatment of neurological diseases.

The oral and maxillofacial region is a highly complex area composed of multiple tissue types and bears various critical functions of the human body. Diseases in this region pose significant diagnostic and management challenges; therefore, exploring new strategies for early diagnosis, targeted treatment, and tissue reconstruction is key to improving patient prognosis and quality of life. Extracellular vesicles are a group of heterogeneous lipid-bilayer membrane structures secreted by most cell types, including exosomes, microvesicles, and apoptotic bodies. Present in various body fluids and tissues, they act as messengers via the transfer of nucleic acids, proteins, and metabolites to recipient cells. To date, studies have revealed the different roles of extracellular vesicles in physiological or pathological processes, as well as applications in disease diagnosis, prognosis, and treatment. The importance and tissue specificity of the dental and maxillofacial tissues indicate that extracellular vesicles derived from this region are promising for further research. This paper reviews the published data on extracellular vesicles derived from cells, body fluids, and tissues in oral and maxillofacial regions, summarizes the latest advances in extracellular vesicles from extensive sources, and concludes with a focus on the current research progress and application prospects of engineered exosomes in oral science.

Adipose-derived stem cells (ADSCs) have become one of the best seed cells widely studied and concerned in tissue engineering because of their rich sources and excellent multi-directional differentiation ability, which are expected to play a practical application role in tissue defect, osteoporosis, plastic surgery, and other fields. However, the differentiation direction of ADSCs is regulated by complex factors. Long non-coding RNAs (lncRNAs) are RNA molecules longer than 500 nucleotides that do not encode proteins and can act as signaling RNAs in response to intracellular and extracellular stimuli. Recently, accumulating evidence has revealed that lncRNAs could regulate the cell cycle and differentiation direction of ADSCs through various mechanisms, including histone modification, binding to RNA-binding proteins, and regulating the expression of miRNAs. Therefore, enriching and elucidating its mechanism of action as well as targeting lncRNAs to regulate ADSCs differentiation have potential prospects in tissue regeneration applications such as bone, blood vessels, and adipose. In this review, we summarize the role and mechanism of lncRNAs and its complexes in the multi-directional differentiation of ADSCs and discuss some potential approaches that can exert therapeutic effects on tissue defects by modulating the expression level of lncRNAs in ADSCs. Our work might provide some new research directions for the clinical applications of tissue engineering.

Nanopore long-read RNA sequencing is reshaping extracellular vesicle (EV) research by providing the capacity to analyze full-length RNA molecules. EVs are crucial for intercellular communication, carrying a diverse range of RNA cargo that can regulate recipient cell behavior. However, traditional short-read sequencing methods involve transcript fragmentation, limiting our understanding of the EV transcriptomic landscape. Furthermore, it has been generally assumed that EV RNAs are likely to be fragmentation products of cellular RNAs, and the extent to which full length RNAs are present within EVs remains to be clarified. Recent advancements in sequencing technology, particularly long-read sequencing by Oxford Nanopore Technologies (ONT), offer a solution to this limitation. Hence, long-read sequencing allows for the analysis of full-length EV RNA molecules, providing deeper insights into their integrity and isoform diversity. Here, we present a comprehensive protocol for EV RNA purification, cDNA library preparation, and sequencing using ONT's MinION platform.

Despite that the clinical application of titanium-based implants has achieved great success, patients' own diseases and/or unhealthy lifestyle habits often lead to implant failure. Many studies have been carried out to modify titanium implants to promote osseointegration and implant success. Recent studies showed that exosomes, proactively secreted extracellular vesicles by mammalian cells, could selectively target and modulate the functions of recipient cells such as macrophages, nerve cells, endothelial cells, and bone marrow mesenchymal stem cells that are closely involved in implant osseointegration. Accordingly, using exosomes to functionalize titanium implants has been deemed as a novel and effective way to improve their osseointegration ability. Herein, recent advances pertaining to surface functionalization of titanium implants with exosomes are analyzed and discussed, with focus on the role of exosomes in regulating the functions of osseointegration-related cells, and their immobilization strategies as well as resultant impact on osseointegration ability.

Musculoskeletal disorders are a series of diseases involving bone, muscle, cartilage, and tendon, mainly caused by chronic strain, degenerative changes, and structural damage due to trauma. The disorders limit the function of patients due to pain and significantly reduce their quality of life. In recent years, adipose-derived mesenchymal stem cells have been extensively applied in regeneration medicine research due to their particular abilities of self-renewal, differentiation, and targeted homing and are more easily accessed compared with other sources. The paracrine effect of ADSCs plays a crucial role in intercellular communication by releasing mass mediators, including cytokines and growth factors, particularly the exosomes they secrete. Not only do these exosomes possess low immunogenicity, low toxicity, and an enhanced ability to penetrate a bio-barrier, but they also inherit their parent cells' characteristics and carry various bioactive molecules to release to targeted cells, modulating their biological process. Meanwhile, these characteristics also make exosomes a natural nanocarrier capable of targeted drug delivery to specific sites, enhancing the bioavailability of drugs within the body and achieving precision therapy with fewer toxic side effects. Furthermore, the integration of exosomes with tissue engineering and chemical modification strategies can also significantly enhance their efficacy in facilitating tissue repair. However, the current research on ADSC-Exos for improving MSDs remains at an early stage and needs further exploration. Therefore, this review summarized the ADSC-Exo as a nanodrug carrier characteristics and mechanism in the treatment of fracture, osteoporosis, osteoarthritis, intervertebral disc degeneration, and tendon injury, which push forward the research progress of ADSC-Exo therapy for MSDs.

Bone defect healing is a multi-factorial process involving the inflammatory microenvironment, bone regeneration and the formation of blood vessels, and remains a great challenge in clinical practice. Combined use of three-dimensional (3D)-printed scaffolds and bioactive factors is an emerging strategy for the treatment of bone defects. Scaffolds can be printed using 3D cryogenic printing technology to create a microarchitecture similar to trabecular bone. Melatonin (MT) has attracted attention in recent years as an excellent factor for promoting cell viability and tissue repair. In this study, porous scaffolds were prepared by cryogenic printing with poly(lactic-co-glycolic acid) and ultralong hydroxyapatite nanowires. The hierarchical pore size distribution of the scaffolds was evaluated by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Sleep-inspired small extracellular vesicles (MT-sEVs) were then obtained from MT-stimulated cells and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly(ethylene glycol)-inorganic pyrophosphate (DSPE-PEG-PPi) was used to modify the membrane of MT-sEVs to obtain PPi-MT-sEVs. RNA sequencing was performed to explore the potential mechanisms. The results demonstrated that PPi-MT-sEVs not only enhanced cell proliferation, migration and angiogenesis, but also regulated the osteogenic/adipogenic fate determination and M1/M2 macrophage polarization switch in vitro. PPi-MT-sEVs were used to coat scaffolds, enabled by the capacity of PPi to bind to hydroxyapatite, and computational simulations were used to analyze the interfacial bonding of PPi and hydroxyapatite. The macrophage phenotype-modulating and osteogenesis-angiogenesis coupling effects were evaluated in vivo. In summary, this study suggests that the combination of hierarchical porous scaffolds and PPi-MT-sEVs could be a promising candidate for the clinical treatment of bone defects.

The molecular regulation mechanisms for maintaining the homeostasis of mesenchymal stem cells still remains poorly defined. Antler reserve mesenchymal cells (RM cells) persist through the whole rapid antler growth stage as a reserved stem cell population capable of division and differentiation, that makes the RM cells a unique model in stem cell regulation and cancer mechanism studies. Herein, we sequenced and analyzed the extracellular vesicles (EVs) of RM cells in the growth center of antler, and identified a high expression level of miR-143-3p and its target genes IGF1R, TGFβ1, BMP2, etc. The upstream positive regulatory factor PRRX1 of miR-143-3p was identified through ATAC and CUT-taq analysis, combined with dual luciferase assay. We showed that PRRX1 overexpression resulted in a decreased proliferation of RM cells and induced a higher expression of miR-143-3p. miR-143-3p enriched EVs derived from PRRX1 overexpression RM cells had an inhibitory effect on RM cells, osteosarcoma 143B cells (considered as excessive proliferation model for RM cells) and in vivo in osteosarcoma bearing mice, and the mRNA and protein levels of IGF1R were significantly reduced. We confirmed that miR-143-3p enriched EVs inhibited 3D culture induced chondrogenic differentiation of RM cells and xenogeneic antler chondrogenesis through targeting TGFβ1 and BMP2. Together, PRRX1 was identified as an activator of miR-143-3p, and higher amounts of miR-143-3p in EVs of RM cells could inhibit excessive proliferation, and help maintain the undifferentiated state of RM cells. We conclude that PRRX1/miR-143-3p signaling was a regulator of homeostasis of antler RM cells and was a potential regulator of osteosarcoma. Our findings are essential for advancing medical and biological sciences, providing new theoretical foundations and strategies for cancer treatment and tissue regeneration.

Critical-sized bone defects represent an urgent clinical problem, necessitating innovative treatment approaches. Gene-activated grafts for bone tissue engineering have emerged as a promising solution. However, traditional gene delivery methods are constrained by limited osteogenic efficacy and safety concerns. Recently, organic and inorganic nanoparticle (NP) vectors have attracted significant attention in bone tissue engineering for their safe, stable, and controllable gene delivery. Targeted gene delivery guided by insights into bone healing mechanisms, coupled with the multifunctional design of NPs, is crucial for enhancing therapeutic outcomes. Here, the theoretical foundations underlying NP-mediated gene therapy for enhancing bone healing across different histological stages are elucidated. Furthermore, the distinct attributes of functionalized NP vectors are discussed, and cutting-edge strategies aimed at optimizing gene delivery efficiency throughout the therapeutic process are highlighted. Additionally, the review addresses the unresolved challenges and prospects of this technology. This review may contribute to the continued development and clinical application of NP-mediated gene delivery for treating critical-sized bone defects.

Osteoarthritis (OA) is a joint disorder caused by wear and tear of the cartilage that cushions the joints. It is a progressive condition that can cause significant pain and disability. Currently, there is no cure for OA, though there are treatments available to manage symptoms and slow the progression of the disease. A chondral defect is a common and devastating lesion that is challenging to treat due to its avascular and aneural nature. However, there are conventional therapies available, ranging from microfracture to cell-based therapy. Anyhow, its efficiency in cartilage defects is limited due to unclear cell viability. Exosomes have emerged as a potent therapeutic tool for chondral defects because they are a complicated complex containing cargo of proteins, DNA, and RNA as well as the ability to target cells due to their phospholipidic composition and the altering exosomal contents that boost regeneration potential. Exosomes are used in a variety of applications, including tissue healing and anti-inflammatory therapy. As in recent years, biomaterials-based bio fabrication has gained popularity among the many printable polymer-based hydrogels, tissue-specific decellularized extracellular matrix might boost the effects rather than an extracellular matrix imitating environment, a short note has been discussed. Exosomes are believed to be the greatest alternative option for current cell-based therapy, and future progress in exosome-based therapy could have a greater influence in the field of orthopaedics. The review focuses extensively on the insights of exosome use and scientific breakthroughs centered OA.

Bioactive molecules have shown great promise for effectively regulating various bone formation processes, rendering them attractive therapeutics for bone regeneration. However, the widespread application of bioactive molecules is limited by their low accumulation and short half-lives in vivo. Hydrogels have emerged as ideal carriers to address these challenges, offering the potential to prolong retention times at lesion sites, extend half-lives in vivo and mitigate side effects, avoid burst release, and promote adsorption under physiological conditions. This review systematically summarizes the recent advances in the development of bioactive molecule-loaded hydrogels for bone regeneration, encompassing applications in cranial defect repair, femoral defect repair, periodontal bone regeneration, and bone regeneration with underlying diseases. Additionally, this review discusses the current strategies aimed at improving the release profiles of bioactive molecules through stimuli-responsive delivery, carrier-assisted delivery, and sequential delivery. Finally, this review elucidates the existing challenges and future directions of hydrogel encapsulated bioactive molecules in the field of bone regeneration.

Deep caries and severe periodontitis cause bone resorption in periodontal tissue, and severe bone resorption leads to tooth loss. Periodontal ligament stem cells (PDLSCs) are important for the healing of defective periodontal tissue. It is increasingly understood that healing of periodontal tissue is mediated through the secretion of trophic factors, particularly exosomes. This study investigated the effects of exosomes from human PDLSCs (HPDLSCs-Exo) on human osteoblast-like cells in vitro and on the healing of rat calvarial bone defects in vivo. HPDLSCs-Exo were isolated and characterized by their particle shape, size (133 ± 6.4 nm), and expression of surface markers (CD9, CD63, and CD81). In vitro results showed that HPDLSCs-Exo promoted the migration, mineralization, and expression of bone-related genes such as alkaline phosphatase (ALP), bone morphogenetic protein 2 (BMP2), osteocalcin (OCN), and osteopontin (OPN) in human osteoblast-like cells. Furthermore, in vivo results showed that more newly formed bone was observed in the HPDLSCs-Exo-treated group than in the non-treated group at the defect sites in rats. These results indicated that HPDLSCs-Exo could promote osteogenesis in vitro and in vivo, and this suggests that HPDLSCs-Exo may be an attractive treatment tool for bone healing in defective periodontal tissue.

Mesenchymal stem cells (MSCs) are widely dispersed in vivo and are isolated from several tissues, including bone marrow, heart, body fluids, skin, and perinatal tissues. Bone marrow MSCs have a multidirectional differentiation potential, which can be induced to differentiate the medium in a specific direction or by adding specific regulatory factors. MSCs repair damaged tissues through lineage differentiation, and the ex vivo transplantation of bone marrow MSCs can heal injured sites. MSCs have different propensities for lineage differentiation and pathological evolution for different diseases, which are crucial in disease progression. In this study, we describe various lineage analysis methods to explore lineage ontology in vitro and in vivo, elucidate the impact of MSC lineage differentiation on diseases, advance our understanding of the role of MSC differentiation in physiological and pathological states, and explore new targets and ideas associated with disease diagnosis and treatment.

Bone regeneration is a complex biological process that relies on the orchestrated interplay of various cellular and molecular events. Bone tissue engineering is currently the most promising method for treating bone regeneration. However, the immunogenicity, stable and cell quantity of seed cells limited their application. Recently, exosomes, which are small extracellular vesicles released by cells, have been found to effectively address these problems and better induce bone regeneration. Meanwhile, a growing line of research has shown the cargos of exosomes may provide effective therapeutic and biomarker tools for bone repair, including miRNA, lncRNA, and proteins. Moreover, engineered scaffolds loaded with exosomes can offer a cell-free bone repair strategy, addressing immunogenicity concerns and providing a more stable functional performance. Herein, we provide a comprehensive summary of the role played by scaffolds loaded with exosomes in bone regeneration, drawing on a systematic analysis of relevant literature available on PubMed, Scopus, and Google Scholar database.

This study sought to elucidate the mechanism of human umbilical cord-derived mesenchymal stem cells (HUCMSCs)-exosomes (Exos) in sepsis-associated acute kidney injury (SAKI). Exos were isolated from HUCMSCs and co-cultured with CD4+ T cells exposed to lipopolysaccharide to detect the effects of HUCMSCs-Exos on CD4+ T cell apoptosis and autophagy. miR-375 expression in CD4+ T cells and HUCMSCs-Exos was examined. The relationship between miR-375 and HDAC4 was analyzed. A mouse model of SAKI was established and injected with HUCMSCs-Exos to verify the function of HUCMSCs-Exos in vivo. HUCMSCs-Exos inhibited lipopolysaccharide-induced apoptosis of CD4+ T cells and promoted autophagy. miR-375 expression was noted to be elevated in the HUCMSCs-Exos. Importantly, HUCMSCs-Exos could deliver miR-375 into CD4+ T cells where miR-375 targeted HDAC4 and negatively regulated its expression. By this mechanism, HUCMSCs-Exos decreased CD4+ T cell apoptosis and augmented autophagy. This finding was further confirmed in an in vivo SAKI model. Collectively, HUCMSCs-Exos can protect against SAKI via delivering miR-375 that promotes autophagy and arrests T cell apoptosis through HDAC4 downregulation. These findings suggest a promising therapeutic potential for HUCMSCs-Exos in the context of SAKI.

Orthodontic relapse (OR) occurs at a rate of over 70%. Retention is the current attempt at prevention, but it requires a considerable amount of time and cannot fully block OR. It's imperative to find a safe and effective method for managing post-orthodontic tooth stability. Periodontal bone remodeling is one crucial biological foundation of OR. Mesenchymal stem cell-derived exosomes (MSC-Exo) show promise in relapse management by regulating periodontal bone remodeling. MSC-Exo can prevent relapse by regulating periodontal ligament function, osteoclast activity, osteoblast differentiation, macrophage polarization, and periodontal microcirculation. In recent years, exosome-loaded hydrogels, which achieve controlled exosome release, have demonstrated efficacy in promoting bone regeneration and remodeling, offering promising prospects for OR management. This review aims to highlight the use of MSC-Exo-based therapy for preventing OR, offering new insights for future research focused on improving tooth stability and enhancing orthodontic anchorage.

The clinical need for effective bone regeneration in compromised conditions continues to drive demand for innovative solutions. Among emerging strategies, extracellular vesicles (EVs) have shown promise as an acellular approach for bone regeneration. However, their efficacy is hindered by rapid sequestration and clearance when administered via bolus injection. To address this challenge, EV-functionalized scaffolds have recently been proposed as an alternative delivery strategy to enhance EV retention and subsequent healing efficacy. This review aims to consolidate recent advancements in the development of EV-functionalized scaffolds for augmenting bone regeneration. It explores various sources of EVs and different strategies for integrating them into biomaterials. Furthermore, the mechanisms underlying their therapeutic effects in bone regeneration are elucidated. Current limitations in clinical translation and perspectives on the design of more efficient EVs for improved therapeutic efficacy are also presented. Overall, this review can provide inspiration for the development of novel EV-assisted grafts with superior bone regeneration potential.

Dental pulp stem cells (DPSCs) demonstrate high proliferative and multilineage differentiation potential. As previously reported, the helioxanthin derivative 4-(4-methoxyphenyl)pyrido[40,30:4,5]thieno[2,3-b]pyridine-2-carboxamide (TH) has been demonstrated to induce the osteogenic differentiation of DPSCs. However, the mechanism of osteogenesis induced by TH in DPSCs remains unknown. The objective of this study was to identify functional extracellular vesicle (EV) microRNAs (miRNAs), and the principal genes involved in the TH-induced osteogenesis of DPSCs. DPSCs were derived from dental pulp extracted from the third molars of three healthy subjects, and were cultured with or without TH. miRNAs were extracted from DPSC-derived EVs. The gene expression patterns of mRNA and miRNA were compared using RNA-Seq and miRNA-Seq. To investigate miRNA/mRNA interacting networks, functional analyses were performed by Ingenuity Pathway Analysis. Alkaline phosphatase (ALP) staining demonstrated that treatment with TH resulted in enhanced ALP activity in DPSCs after 7 days. The expression levels of ALP and type 1 collagen alpha 1 were significantly higher in TH-induced DPSCs on day 7. RNA-Seq and miRNA-Seq analyses identified 869 differentially expressed genes (DEGs) and 18 miRNA-DEGs. Gene Ontology analysis of the mRNA-Seq results showed that TH induced several biological activities associated with signal transduction, cell adhesion, and cell differentiation. Integrated miRNA-mRNA analyses showed that these miRNAs contain the targeting information of 277 mRNAs of the DEGs. Among them, 17 target genes known to be involved in the differentiation of osteoblasts, and 24 target genes known to be involved in the differentiation of bone cells were identified. Quantitative real-time PCR showed that WNT5a expression in DPSCs was upregulated by 48 h of TH treatment. Upstream regulator analysis indicated that WNT3a, FOS, and RAC1 may be responsible for gene expression changes in DPSCs after TH treatment. EV miRNA regulatory networks might play crucial roles in TH-induced osteogenic differentiation of DPSCs. Our results presented herein offer valuable insights that will facilitate further research into the mechanism of osteogenesis of DPSCs, which is expected to lead to the clinical application of TH-induced DPSCs for bone regeneration. Furthermore, EVs derived from TH-induced DPSCs might be useful as therapeutic tools for bone defects.

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

The present study aimed to explore the function of human bone marrow mesenchymal stem cells (hBMMSCs)-derived exosomal long noncoding RNA histocompatibility leukocyte antigen complex P5 (HCP5) in the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) to improve chronic periodontitis (CP).

Exosomes were extracted from hBMMSCs. Alizarin red S staining was used to detect mineralised nodules. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to measure HCP5 and miR-24-3p expression. The mRNA and protein levels of alkaline phosphatase (ALP), osteocalcin, osterix, runt-related transcription factor 2, bone morphogenetic protein 2, osteopontin, fibronectin, collagen 1, heme oxygenase 1 (HO1), P38, and ETS transcription factor ELK1 (ELK1) were detected using RT-qPCR and Western blot. Enzyme-linked immunosorbent assay (ELISA) kits were used to determine the HO1 and carbon monoxide concentrations. Heme, biliverdin, and Fe2+ levels were determined using detection kits. Micro-computed tomography, hematoxylin and eosin staining, ALP staining, tartrate-resistant acid phosphatase staining, ELISA, and RT-qPCR were conducted to evaluate the effect of HCP5 on CP mice. Dual luciferase, RNA immunoprecipitation, and RNA pulldown experiments were performed to identify the interactions among HCP5, miR-24-3p, and HO1.

The osteogenic ability of hPDLSCs significantly increased when co-cultured with hBMMSCs or hBMMSCs exosomes. Overexpression of HCP5 and HO1 in hBMMSCs exosomes promoted the osteogenic differentiation of hPDLSCs, and knockdown of HCP5 repressed the osteogenic differentiation of hPDLSCs. HCP5 knockdown enhanced the inflammatory response and repressed osteogenesis in CP mice. MiR-24-3p overexpression diminished the stimulatory effect of HCP5 on the osteogenic ability of hPDLSCs. Mechanistically, HCP5 acted as a sponge for miR-24-3p and regulated HO1 expression, and HO1 activated the P38/ELK1 pathway.

HBMMSCs-derived exosomal HCP5 promotes the osteogenic differentiation of hPDLSCs and alleviates CP by regulating the miR-24-3p/HO1/P38/ELK1 signalling pathway.

It is common for maladies and trauma to cause significant bone deterioration in the craniofacial bone, which can cause patients to experience complications with their appearance and their ability to function. Regarding grafting procedures' complications and disadvantages, the newly emerging field of tissue regeneration has shown promise. Tissue -engineered technologies and their applications in the craniofacial region are increasingly gaining prominence with limited postoperative risk and cost. MSCs-derived exosomes are widely applied in bone tissue engineering to provide cell-free therapies since they not only do not cause immunological rejection in the same way that cells do, but they can also perform a cell-like role. Additionally, the hydrogel system is a family of multipurpose platforms made of cross-linked polymers with considerable water content, outstanding biocompatibility, and tunable physiochemical properties for the efficient delivery of commodities. Therefore, the promising exosome-loaded hydrogels can be designed for craniofacial bone regeneration. This review lists the packaging techniques for exosomes and hydrogel and discusses the development of a biocompatible hydrogel system and its potential for exosome continuous delivery for craniofacial bone healing.

Exosomes, endogenous vesicles secreted by cells, possess unique properties like high biocompatibility, low immunogenicity, targeting ability, long half-life, and blood-brain barrier permeability. They serve as crucial intercellular communication vectors in physiological processes and disease occurrence. Our comprehensive analysis of exosome-based drug delivery research from 2013 to 2023 revealed 2,476 authors from 717 institutions across 33 countries. Keyword clustering identified five research areas: drug delivery, mesenchymal stem cells, cancer immunotherapy, targeting ligands, surface modifications, and macrophages. The combination of exosome drug delivery technology with a proven clinical model enables the precise targeting of tumors with chemotherapy or radiosensitising agents, as well as facilitating gene therapy. This bibliometric analysis aims to characterize the current state and advance the clinical application of exosome-based drug delivery systems.

Efforts are made to enhance the inherent potential of extracellular vesicles (EVs) by utilizing 3D culture platforms and engineered strategies for functional cargo-loading. Three distinct types of adipose mesenchymal stem cells-derived EVs (ADSCs-EVs) are successfully isolated utilizing 3D culture platforms consisting of porous gelatin methacryloyl (PG), PG combined with sericin methacryloyl (PG/SerMA), or PG combined with chondroitin sulfate methacryloyl (PG/ChSMA). These correspond to PG-EVs, PG/SerMA-EVs, and PG/ChSMA-EVs, respectively. Unique microRNA (miRNA) profiles are observed in each type of ADSCs-EVs. Notably, PG-EVs encapsulate higher levels of hsa-miR-455-3p and deliver more hsa-miR-455-3p to chondrocytes, which results in the activation of the hsa-miR-455-3p/PAK2/Smad2/3 axis and the subsequent hyaline cartilage regeneration. Furthermore, the functionality of PG-EVs is optimized through engineered strategies, including agomir/lentivirus transfection, electroporation, and Exo-Fect transfection. These strategies, referred to as Agomir-EVs, Lentivirus-EVs, Electroporation-EVs, and Exo-Fect-EVs, respectively, are ranked based on their efficacy in encapsulating hsa-miR-455-3p, delivering hsa-miR-455-3p to chondrocytes, and promoting cartilage formation via the hsa-miR-455-3p/PAK2/Smad2/3 axis. Notably, Exo-Fect-EVs exhibit the highest efficiency. Collectively, the 3D culture conditions and engineered strategies have an impact on the miRNA profiles and cartilage regeneration capabilities of ADSCs-EVs. The findings provide valuable insights into the mechanisms underlying the promotion of cartilage regeneration by ADSCs-EVs.

Chronic wound healing is a class of diseases influenced by multiple complex factors, causing severe psychological and physiological impact on patients. It is an intractable clinical challenge and its possible mechanisms are not yet clear. It has been proven that adipose stem cell-derived exosomes (ADSC-Exos) can promote wound healing and inhibit scar formation by regulating inflammation, promoting cell proliferation, migration, and angiogenesis, regulating matrix remodeling, which provides a new approach for wound healing through biological treatment. This review focuses on the mechanism, treatment, and administration methods of ADSC-Exos in wound healing, providing a comprehensive understanding the mechanisms of ADSC-Exos on wound healing. LEVEL OF EVIDENCE I: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exosomes, nanoparticles secreted by various cells, composed of a bilayer lipid membrane, and containing bioactive substances such as proteins, nucleic acids, metabolites, etc., have been intensively investigated in tissue engineering owing to their high biocompatibility and versatile biofunction. However, there is still a lack of a high-quality review on bone defect regeneration potentiated by exosomes. In this review, the biogenesis and isolation methods of exosomes are first introduced. More importantly, the engineered exosomes of the current state of knowledge are discussed intensively in this review. Afterward, the biomaterial carriers of exosomes and the mechanisms of bone repair elucidated by compelling evidence are presented. Thus, future perspectives and concerns are revealed to help devise advanced modalities based on exosomes to overcome the challenges of bone regeneration. It is totally believed this review will attract special attention from clinicians and provide promising ideas for their future works.

In addition to its recognized role in providing structural support, bone plays a crucial role in maintaining the functionality and balance of various organs by secreting specific cytokines (also known as osteokines). This reciprocal influence extends to these organs modulating bone homeostasis and development, although this aspect has yet to be systematically reviewed. This review aims to elucidate this bidirectional crosstalk, with a particular focus on the role of osteokines. Additionally, it presents a unique compilation of evidence highlighting the critical function of extracellular vesicles (EVs) within bone-organ axes for the first time. Moreover, it explores the implications of this crosstalk for designing and implementing bone-on-chips and assembloids, underscoring the importance of comprehending these interactions for advancing physiologically relevant in vitro models. Consequently, this review establishes a robust theoretical foundation for preventing, diagnosing, and treating diseases related to the bone-organ axis from the perspective of cytokines, EVs, hormones, and metabolites.

Skeletal diseases impose a considerable burden on society. The clinical and tissue-engineering therapies applied to alleviate such diseases frequently result in complications and are inadequately effective. Research has shifted from conventional therapies based on mesenchymal stem cells (MSCs) to exosomes derived from MSCs. Exosomes are natural nanocarriers of endogenous DNA, RNA, proteins, and lipids and have a low immune clearance rate and good barrier penetration and allow targeted delivery of therapeutics. MSC-derived exosomes (MSC-exosomes) have the characteristics of both MSCs and exosomes, and so they can have both immunosuppressive and tissue-regenerative effects. Despite advances in our knowledge of MSC-exosomes, their regulatory mechanisms and functionalities are unclear. Here we review the therapeutic potential of MSC-exosomes for skeletal diseases.

Adipose-derived stem cells (ADSCs) are a subset of mesenchymal stem cells (MSCs) isolated from adipose tissue. They possess remarkable properties, including multipotency, self-renewal, and easy clinical availability. ADSCs are also capable of promoting tissue regeneration through the secretion of various cytokines, factors, and extracellular vesicles (EVs). ADSC-derived EVs (ADSC-EVs) act as intercellular signaling mediators that encapsulate a range of biomolecules. These EVs have been found to mediate the therapeutic activities of donor cells by promoting the proliferation and migration of effector cells, facilitating angiogenesis, modulating immunity, and performing other specific functions in different tissues. Compared to the donor cells themselves, ADSC-EVs offer advantages such as fewer safety concerns and more convenient transportation and storage for clinical application. As a result, these EVs have received significant attention as cell-free therapeutic agents with potential future application in regenerative medicine. In this review, we focus on recent research progress regarding regenerative medical use of ADSC-EVs across various medical conditions, including wound healing, chronic limb ischemia, angiogenesis, myocardial infarction, diabetic nephropathy, fat graft survival, bone regeneration, cartilage regeneration, tendinopathy and tendon healing, peripheral nerve regeneration, and acute lung injury, among others. We also discuss the underlying mechanisms responsible for inducing these therapeutic effects. We believe that deciphering the biological properties, therapeutic effects, and underlying mechanisms associated with ADSC-EVs will provide a foundation for developing a novel therapeutic approach in regenerative medicine.

In recent years, different advancements have been observed in nanosized drug delivery systems. Factors such as stability, safety and targeting efficiency cause hindrances in the clinical translation of these synthetic nanocarriers. Therefore, researchers employed endogenous nanocarriers like exosomes as drug delivery vehicles that have an inherent ability to target more efficiently after appropriate functionalization and show higher biocompatibility and less immunogenicity and facilitate penetration through the biological barriers more quickly than the other available carriers. Exosomes are biologically derived lipid bilayer-enclosed nanosized extracellular vesicles (size ranges from 30 to 150 nm) secreted from both prokaryotic and eukaryotic cells and appears significantly in the extracellular space. These EVs (extracellular vesicles) can exist in different sources, including mammals, plants and microorganisms. Different advanced techniques have been introduced for the isolation of exosomes to overcome the existing barriers present with conventional methods. Extensive research on the application of exosomes in therapeutic delivery for treating various diseases related to central nervous system, bone, cancer, skin, etc. has been employed. Several studies are on different stages of clinical trials, and many exosomes patents have been registered.