Exosomes Derived from Epidermal Stem Cells Improve Diabetic Wound Healing

Global Hotspots and Trends of Diabetic Foot Ulcer Therapy: A Bibliometric Analysis from 2004 and 2023

Diabetic foot ulcer (DFU) is a common complication of diabetes, associated with increased rates of amputation and mortality. In recent years, great progress has been made in the treatment of DFU, but there is still a lack of bibliometric research on the treatment of DFU.DFU therapy publications published between 1 January 2004 and 31 December 2023 were retrieved from the Web of Science Core Collection (WoSCC) database for analysis using VOSviewer and CiteSpace analytics. A total of 4833 publications on DFU from 2004 to 2023 were included in the WoSCC database. The United States had the highest productivity with 1463 papers, accounting for 30.27% of the total production, followed by China with 907 papers (18.77%) and England with 438 papers (9.06%). In terms of research institutions and journals, the University of Texas System and Journal of Wound Care published the highest number of papers. High-frequency keywords in the field of DFU therapy mainly concentrated on management, wound healing, and amputation. This study conducted a systematic bibliometric analysis of DFU therapy publications from 2004 and 2025. Improving DFU management, promoting wound healing, and reducing amputation rates are the hotspots and future trends in this field. Our work provides valuable insights into the research trajectory and future avenues of exploration in the field of DFU therapy. These findings provide strong support for academic research and clinical practice.

Exploring the ncRNA landscape in exosomes: Insights into wound healing mechanisms and therapeutic applications

Exosomal non-coding RNAs (ncRNAs), including miRNAs, lncRNAs, and circRNAs, have emerged as crucial modulators in cellular signaling, influencing wound healing processes. Stem cell-derived exosomes, which serve as vehicles for these ncRNAs, show remarkable therapeutic potential due to their ability to modulate wound healing stages, from initial inflammation to collagen formation. These ncRNAs act as molecular signals, regulating gene expression and protein synthesis necessary for cellular responses in healing. Wound healing is a complex, staged process involving inflammation, hemostasis, fibroblast proliferation, angiogenesis, and tissue remodeling. Stem cell-derived exosomal ncRNAs enhance these stages by reducing excessive inflammation, promoting anti-inflammatory responses, guiding fibroblast and keratinocyte maturation, enhancing vascularization, and ensuring organized collagen deposition. Their molecular cargo, particularly ncRNAs, specifically targets pathways to aid chronic wound repair and support scarless regeneration. This review delves into the unique composition and signaling roles of Stem cell-derived exosomes and ncRNAs, highlighting their impact across wound healing stages and their potential as innovative therapeutics. Understanding the interaction between exosomal ncRNAs and cellular signaling pathways opens new avenues in regenerative medicine, positioning Stem cell-derived exosomes and their ncRNAs as promising molecular-level interventions in wound healing.

HMGB1 Accelerates Wound Healing by Promoting the Differentiation of Epidermal Stem Cells via the "HMGB1-TLR4-Wnt/Notch" Axis

Objective: Impairments in the differentiation and migratory capacity of epidermal stem cells (ESCs) are pivotal factors contributing to delayed wound healing. High mobility group box1 (HMGB1) has recently emerged as a potential target for tissue repair. Therefore, we aimed to investigate the role and molecular mechanisms of HMGB1 in ESCs during the wound-healing process. Approach: Initially, we examined the expression of HMGB1 and the differentiation of ESCs in normal skin, normal wounds and chronic wounds. Then, we assessed the ESC migration and differentiation, and the key markers in the Wnt/Notch signaling pathways, after treatment of HMGB1 and inhibitor, and the knockdown of toll-like receptor 4 (TLR4), using scratch assay, qPCR, western blotting, and immunofluorescence. Finally, we conducted mice models to analyze the healing rates and quality in vivo. Results: HMGB1 was decreased across all epidermal layers, and the differentiation of ESCs was hindered in diabetic foot ulcer. In vitro, HMGB1 enhanced both the migration and differentiation of ESCs while stimulating the expression of the Wnt/Notch pathway within ESCs. However, the downregulation of TLR4 negated these effects. Finally, our in vivo experiments provided evidence that HMGB1 facilitates wound healing and epidermis differentiation via TLR4 and Wnt/Notch signaling pathways. Innovation: This study innovatively introduces HMGB1 as a novel target for skin wound healing and elucidates its mechanisms of action. Conclusions: HMGB1 accelerated wound healing by promoting the differentiation of epidermal stem cells through the "HMGB1-TLR4-Wnt/Notch" axis, which reveals a new potential mechanism and target to expedite wound healing.

Epidermal stem cell-derived exosomes improve wound healing by promoting the proliferation and migration of human skin fibroblasts

Background

Epidermal stem cells (ESCs) are primarily located in the basal layer of the epidermis and play a crucial role in wound healing. ESCs-derived exosomes (ESCs-Exo) are emerging as promising candidates for skin regeneration and wound healing. However, the underlying mechanisms remain unclear. This study aims to investigate the role and mechanisms of ESCs-Exo in promoting the proliferation, migration, and collagen synthesis of human skin fibroblasts (HSFBs).

Methods

This study generated, isolated, and characterized ESC-Exos. The effects of ESCs-Exo on the proliferation of human skin fibroblasts (HSFBs) were detected via Cell Counting Kit-8 (CCK8), 5-Ethynyl-2'-deoxyuridine (EdU), and Proliferating Cell Nuclear Antigen (PCNA) and Marker of Proliferation Ki-67 (MKI67) gene expression methods. The effect of ESCs-Exo on the migration of HSFBs was detected via a transwell assay and a scratch test. The concentrations of collagen secreted by the HSFBs and the mRNAs of the two kinds of collagen expressed by the HSFBs were analyzed. We also analyzed the phosphorylation of Protein Kinase N1 (PKN1) and the expression of cyclins via western blotting. Finally, the effect of ESCs-Exo on wound healing was verified by animal experiments, and the key genes and signaling pathways of ESCs-Exo were excavated by transcriptomic analysis.

Results

Western blotting revealed that the exosomes of ESCs highly expressed established markers such as Alix, CD63, and CD9. ESC-Exos significantly promoted HSFB proliferation and migration in a dose-dependent manner, as well as HSFB collagen synthesis, and effectively increased the ratio of collagen III/I. In addition, bioinformatics analysis showed that the expression of key gene C-X-C motif chemokine ligand 9 was lower in the ESCs-Exo group, which may promote wound healing by regulating PKN1-cyclin and tumor necrosis factor signaling pathways. Animal experiments demonstrated that ESCs-Exo could reduce inflammation and accelerate wound healing.

Conclusions

In this study, we found that ESCs-Exo may improve wound healing by promoting the proliferation and migration of HSFBs.

Exosomes derived from minor salivary gland mesenchymal stem cells: a promising novel exosome exhibiting pro-angiogenic and wound healing effects similar to those of adipose-derived stem cell exosomes

BACKGROUNDS

Minor salivary gland mesenchymal stem cells (MSGMSCs) can be easily extracted and have a broad range of sources. Applying exosomes to wounds is a highly promising method for promoting wound healing. Exosomes derived from different stem cell types have been proven to enhance wound healing, with adipose-derived stem cell (ADSC)-derived exosomes being the most extensively researched. Considering that MSGMSCs have advantages such as easier extraction compared to ADSCs, MSGMSCs should also be a very promising type of stem cell in exosome therapy. However, whether MSGMSC-derived exosomes (MSGMSC-exos) can promote wound healing and how they compare to ADSC-derived exosomes (ADSC-exos) in the wound healing process remain unclear.

MATERIALS

The effects of MSGMSC-exos and ADSC-exos on angiogenesis in wound healing were investigated in vitro using CCK-8, scratch assays, and tube formation assays. Subsequently, the promotion of wound healing by MSGMSC-exos and ADSC-exos was evaluated in vivo using a full-thickness wound defect model in mice. Immunohistochemistry was used to verify the effects of MSGMSC-exos and ADSC-exos on promoting collagen deposition, angiogenesis, and cell proliferation in the wound. Immunofluorescence staining was performed to investigate the role of MSGMSC-exos and ADSC-exos in modulating the inflammatory response in the wound. Furthermore, proteomic sequencing was conducted to investigate the functional similarities and differences between the proteomes of MSGMSC-exos and ADSC-exos, with key protein contents verified by ELISA.

RESULTS

MSGMSC-exos exhibited similar effects as ADSC-exos in promoting the migration, proliferation, and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro, with a comparable dose-dependent effect. In vivo experiments confirmed that MSGMSC-exos have similar wound healing-promoting functions as ADSC-exos. MSGMSC-exos promoted the neovascularization and maturation of blood vessels in vivo at a level comparable to ADSC-exos. Despite MSGMSC-exos showing less collagen deposition than ADSC-exos, they exhibited stronger anti-scar formation and anti-inflammatory effects. Proteomic analysis revealed that the proteins promoting wound healing in both MSGMSC-exos and ADSC-exos were relatively conserved, with ITGB1 identified as a critical protein for angiogenesis. Further differential analysis revealed that the functions specifically enriched in MSGMSC-exos and ADSC-exos reflected the functions of their source tissue.

CONCLUSIONS

Our study confirms that MSGMSC-exos exhibit highly similar wound healing and angiogenesis-promoting functions compared to ADSC-exos, and the proteins involved in promoting wound healing in both are relatively conserved. Moreover, MSGMSC-exos show stronger anti-scar formation and anti-inflammatory effects than ADSC-exos. This suggests that MSGMSCs are a promising stem cell source with broad applications in wound healing treatment.

Disulfiram-loaded nanovesicles hydrogel promotes healing of diabetic wound

BACKGROUND

Traditional methods for treating diabetic wounds are limited in effectiveness because of their long healing times, the risk of immune rejection, and susceptibility to infection. Suppressing neutrophil extracellular traps (NETs) is an effective strategy for reducing persistent inflammation in diabetic wounds. Although disulfiram (DSF) can inhibit the significant increase of NETs in diabetic wounds, oral DSF suffers from rapid and harmful metabolism in the liver. To address these challenges, we developed a nanomedicine formulation in which DSF was incorporated into the hydrogel.

METHODS

In this study, we developed a DSF-laden sodium alginate hydrogel wound dressing, DEP@SA, and characterized its composition, properties, and performance. We examined the effects of DEP@SA on inflammatory phase-related markers such as NETs and their pathway proteins, inflammatory factors, and macrophage phenotypes in a high-glucose environment in vivo and in vitro. In addition, the effects of DEP@SA on tissue regenerative capacity such as epidermal proliferative migration and angiogenesis, were also assessed.

RESULTS

The results showed that by utilizing extracellular vesicles as a drug delivery system, we effectively mitigated the degradation of DSF via direct contact with aqueous solutions and ensured the stability of DSF@SA, which could then be applied to diabetic wounds. The inflammatory phase-related indicators revealed that DSF@SA effectively reduced inflammation levels, decreased NETs formation, suppressed the Caspase-1/GSDMD pathway in neutrophils, and promoted the polarization of M2 macrophages. Moreover, the hydrogel accelerated wound healing by promoting angiogenesis and re-epithelialization, thereby shortening the diabetic wound healing time.

CONCLUSIONS

This study confirmed that the DSF@SA composite dressing has the potential to enhance diabetic wound repair and offers a novel approach for drug reutilization.

Exosomes from mesenchymal stem cells: Potential applications in wound healing

Wound healing is a continuous and complex process regulated by multiple factors, which has become an intractable clinical burden. Mesenchymal stem cell-derived exosomes (MSC-exos) possess low immunogenicity, easy preservation, and potent bioactivity, which is a mirror to their parental cells MSC-exos are important tools for regulating the biological behaviors of wound healing-associated cells, including fibroblasts, keratinocytes, immune cells, and endothelial cells. MSC-exos accelerate the wound healing process at cellular and animal levels by modulating inflammatory responses, promoting collagen deposition and vascularization. MSC-exos accelerate wound healing at the cellular and animal levels by modulating inflammatory responses and promoting collagen deposition and vascularization. This review summarizes the roles and mechanisms of MSC-exos originating from various sources in promoting the healing efficacy of general wounds, diabetic wounds, burn wounds, and healing-related scars. It also discusses the limitations and perspectives of MSC-exos in wound healing, in terms of exosome acquisition, mechanistic complexity, and exosome potentiation modalities. A deeper understanding of the properties and functions of MSC-exos is beneficial to advance the therapeutic approaches for achieving optimal wound healing.

Exosome-based cell therapy for diabetic foot ulcers: Present and prospect

Diabetic foot ulcers (DFUs) represent a serious complication of diabetes with high incidence, requiring intensive treatment, prolonged hospitalization, and high costs. It poses a severe threat to the patient's life, resulting in substantial burdens on patient and healthcare system. However, the therapy of DFUs remains challenging. Therefore, exploring cell-free therapies for DFUs is both critical and urgent. Exosomes, as crucial mediators of intercellular communication, have been demonstrated potentially effective in anti-inflammation, angiogenesis, cell proliferation and migration, and collagen deposition. These functions have been proven beneficial in all stages of diabetic wound healing. This review aims to summarize the role and mechanisms of exosomes from diverse cellular sources in diabetic wound healing research. In addition, we elaborate on the challenges for clinical application, discuss the advantages of membrane vesicles as exosome mimics in wound healing, and present the therapeutic potential of exosomes and their mimetic vesicles for future clinical applications.

Macrophage and Neutrophil Dysfunction in Diabetic Wounds

Significance: The incidence of diabetes continues to rise throughout the world in an alarming rate. Diabetic patients often develop diabetic foot ulcers (DFUs), many of which do not heal. Non-healing DFUs are a major cause of hospitalization, amputation, and increased morbidity. Understanding the underlying mechanisms of impaired healing in DFU is crucial for its management. Recent Advances: This review focuses on the recent advancements on macrophages and neutrophils in diabetic wounds and DFUs. In particular, we discuss diabetes-induced dysregulations and dysfunctions of macrophages and neutrophils. Critical Issues: It is well established that diabetic wounds are characterized by stalled inflammation that results in impaired healing. Recent findings in the field suggest that dysregulation of macrophages and neutrophils plays a critical role in impaired healing in DFUs. The delineation of mechanisms that restore macrophage and neutrophil function in diabetic wound healing is the focus of intense investigation. Future Directions: The breadth of recently generated knowledge on the activity of macrophages and neutrophils in diabetic wound healing is impressive. Experimental models have delineated pathways that hold promise for the treatment of diabetic wounds and DFUs. These pathways may be useful targets for further clinical investigation.

Comparative Analysis of Exosomes and Extracellular Microvesicles in Healing Pathways: Insights for Advancing Regenerative Therapies

Exosomes and microvesicles bear great potential to broaden therapeutic options in the clinical context. They differ in genesis, size, cargo, and composition despite their similarities. They were identified as participating in various processes such as angiogenesis, cell migration, and intracellular communication. Additionally, they are characterized by their natural biocompatibility. Therefore, researchers concluded that they could serve as a novel curative method capable of achieving unprecedented results. Indeed, in experiments, they proved remarkably efficient in enhancing wound regeneration and mitigating inflammation. Despite immense advancements in research on exosomes and microvesicles, the time for their large-scale application is yet to come. This article aims to gather and analyze current knowledge on those promising particles, their characteristics, and their potential clinical implementations.

Novel Biomaterials for Wound Healing and Tissue Regeneration

Skin is the first defense barrier of the human body, which can resist the invasion of external dust, microorganisms and other pollutants, and ensure that the human body maintains the homeostasis of the internal environment. Once the skin is damaged, the health threat to the human body will increase. Wound repair and the human internal environment are a dynamic process. How to effectively accelerate the healing of wounds without affecting the internal environment of the human body and guarantee that the repaired tissue retains its original function as much as possible has become a research hotspot. With the advancement of technology, researchers have combined new technologies to develop and prepare various types of materials for wound healing. This article will introduce the wound repair materials developed and prepared in recent years from three types: nanofibers, composite hydrogels, and other new materials. The paper aims to provide reference for researchers in related fields to develop and prepare multifunctional materials. This may be helpful to design more ideal materials for clinical application, and then achieve better wound healing and regeneration effects.

Engineered exosomes as a prospective therapy for diabetic foot ulcers

Diabetic foot ulcer (DFU), characterized by high recurrence rate, amputations and mortality, poses a significant challenge in diabetes management. The complex pathology involves dysregulated glucose homeostasis leading to systemic and local microenvironmental complications, including peripheral neuropathy, micro- and macro-angiopathy, recurrent infection, persistent inflammation and dysregulated re-epithelialization. Novel approaches to accelerate DFU healing are actively pursued, with a focus on utilizing exosomes. Exosomes are natural nanovesicles mediating cellular communication and containing diverse functional molecular cargos, including DNA, mRNA, microRNA (miRNA), lncRNA, proteins, lipids and metabolites. While some exosomes show promise in modulating cellular function and promoting ulcer healing, their efficacy is limited by low yield, impurities, low loading content and inadequate targeting. Engineering exosomes to enhance their curative activity represents a potentially more efficient approach for DFUs. This could facilitate focused repair and regeneration of nerves, blood vessels and soft tissue after ulcer development. This review provides an overview of DFU pathogenesis, strategies for exosome engineering and the targeted therapeutic application of engineered exosomes in addressing critical pathological changes associated with DFUs.

Global trends in publications regarding macrophages-related diabetic foot ulcers in the last two decades

BACKGROUND

Diabetic foot ulcers (DFUs) are one of the most severe and popular complications of diabetes. The persistent non-healing of DFUs is the leading cause of ampu-tation, which causes significant mental and financial stress to patients and their families. Macrophages are critical cells in wound healing and perform essential roles in all phases of wound healing. However, no studies have been carried out to systematically illustrate this area from a scientometric point of view. Although there have been some bibliometric studies on diabetes, reports focusing on the investigation of macrophages in DFUs are lacking.

AIM

To perform a bibliometric analysis to systematically assess the current state of research on macrophage-related DFUs.

METHODS

The publications of macrophage-related DFUs from January 1, 2004, to December 31, 2023, were retrieved from the Web of Science Core Collection on January 9, 2024. Four different analytical tools: VOSviewer (v1.6.19), CiteSpace (v6.2.R4), HistCite (v12.03.07), and Excel 2021 were used for the scientometric research.

RESULTS

A total of 330 articles on macrophage-related DFUs were retrieved. The most published countries, institutions, journals, and authors in this field were China, Shanghai Jiao Tong University of China, Wound Repair and Regeneration, and Aristidis Veves. Through the analysis of keyword co-occurrence networks, historical direct citation networks, thematic maps, and trend topics maps, we synthesized the prevailing research hotspots and emerging trends in this field.

CONCLUSION

Our bibliometric analysis provides a comprehensive overview of macrophage-related DFUs research and insights into promising upcoming research.

Exosomes: compositions, biogenesis, and mechanisms in diabetic wound healing

Diabetic wounds are characterized by incomplete healing and delayed healing, resulting in a considerable global health care burden. Exosomes are lipid bilayer structures secreted by nearly all cells and express characteristic conserved proteins and parent cell-associated proteins. Exosomes harbor a diverse range of biologically active macromolecules and small molecules that can act as messengers between different cells, triggering functional changes in recipient cells and thus endowing the ability to cure various diseases, including diabetic wounds. Exosomes accelerate diabetic wound healing by regulating cellular function, inhibiting oxidative stress damage, suppressing the inflammatory response, promoting vascular regeneration, accelerating epithelial regeneration, facilitating collagen remodeling, and reducing scarring. Exosomes from different tissues or cells potentially possess functions of varying levels and can promote wound healing. For example, mesenchymal stem cell-derived exosomes (MSC-exos) have favorable potential in the field of healing due to their superior stability, permeability, biocompatibility, and immunomodulatory properties. Exosomes, which are derived from skin cellular components, can modulate inflammation and promote the regeneration of key skin cells, which in turn promotes skin healing. Therefore, this review mainly emphasizes the roles and mechanisms of exosomes from different sources, represented by MSCs and skin sources, in improving diabetic wound healing. A deeper understanding of therapeutic exosomes will yield promising candidates and perspectives for diabetic wound healing management.

The science of exosomes: Understanding their formation, capture, and role in cellular communication

Extracellular vesicles (EVs) serve as a crucial method for transferring information among cells, which is vital in multicellular organisms. Among these vesicles, exosomes are notable for their small size, ranging from 20 to 150 nm, and their role in cell-to-cell communication. They carry lipids, proteins, and nucleic acids between cells. The creation of exosomes begins with the inward budding of the cell membrane, which then encapsulates various macromolecules as cargo. Once filled, exosomes are released into the extracellular space and taken up by target cells via endocytosis and similar processes. The composition of exosomal cargo varies, encompassing diverse macromolecules with specific functions. Because of their significant roles, exosomes have been isolated from various cell types, including cancer cells, endothelial cells, macrophages, and mesenchymal cells, with the aim of harnessing them for therapeutic applications. Exosomes influence cellular metabolism, and regulate lipid, glucose, and glutamine pathways. Their role in pathogenesis is determined by their cargo, which can manipulate processes such as apoptosis, proliferation, inflammation, migration, and other molecular pathways in recipient cells. Non-coding RNA transcripts, a common type of cargo, play a pivotal role in regulating disease progression. Exosomes are implicated in numerous biological and pathological processes, including inflammation, cancer, cardiovascular diseases, diabetes, wound healing, and ischemic-reperfusion injury. As a result, they hold significant potential in the treatment of both cancerous and non-cancerous conditions.

Relieving Macrophage Dysfunction by Inhibiting SREBP2 Activity: A Hypoxic Mesenchymal Stem Cells-Derived Exosomes Loaded Multifunctional Hydrogel for Accelerated Diabetic Wound Healing

Macrophage dysfunction is one of the primary factors leading to the delayed healing of diabetic wounds. Hypoxic bone marrow mesenchymal stem cells-derived exosomes (hyBMSC-Exos) have been shown to play an active role in regulating cellular function through the carried microRNAs. However, the administration of hyBMSC-Exos alone in diabetic wounds usually brings little effect, because the exosomes are inherently unstable and have a short retention time at the wounds. In this study, a multifunctional hydrogel based on gallic acid (GA) conjugated chitosan (Chi-GA) and partially oxidized hyaluronic acid (OHA) is prepared for sustained release of hyBMSC-Exos. The hydrogel not only exhibits needs-satisfying physicochemical properties, but also displays outstanding biological performances such as low hemolysis rate, strong antibacterial capacity, great antioxidant ability, and excellent biocompatibility. It has the ability to boost the stability of hyBMSC-Exos, leading to a continuous and gradual release of the exosomes at wound locations, ultimately enhancing the exosomes' uptake efficiency by target cells. Most importantly, hyBMSC-Exos loaded hydrogel shows an excellent ability to promote diabetic wound healing by regulating macrophage polarization toward M2 phenotype. This may be because exosomal miR-4645-5p and antioxidant property of the hydrogel synergistically inhibit SREBP2 activity in macrophages. This study presents a productive approach for managing diabetic wounds.

Stem Cell-Derived Extracellular Vesicles: Promising Therapeutic Opportunities for Diabetic Wound Healing

Wound healing is a sophisticated and orderly process of cellular interactions in which the body restores tissue architecture and functionality following injury. Healing of chronic diabetic wounds is difficult due to impaired blood circulation, a reduced immune response, and disrupted cellular repair mechanisms, which are often associated with diabetes. Stem cell-derived extracellular vesicles (SC-EVs) hold the regenerative potential, encapsulating a diverse cargo of proteins, RNAs, and cytokines, presenting a safe, bioactivity, and less ethical issues than other treatments. SC-EVs orchestrate multiple regenerative processes by modulating cellular communication, increasing angiogenesis, and promoting the recruitment and differentiation of progenitor cells, thereby potentiating the reparative milieu for diabetic wound healing. Therefore, this review investigated the effects and mechanisms of EVs from various stem cells in diabetic wound healing, as well as their limitations and challenges. Continued exploration of SC-EVs has the potential to revolutionize diabetic wound care.

Functional biomacromolecules-based microneedle patch for the treatment of diabetic wound

Diabetic wounds are a common complication of diabetes. The prolonged exposure to high glucose and oxidative stress in the wound environment increases the risk of bacterial infection and abnormal angiogenesis, leading to amputation. Microneedle patches have shown promise in promoting the healing of diabetic wounds through transdermal drug delivery. These patches target the four main aspects of diabetic wound treatment: hypoglycemia, antibacterial action, inflammatory regulation, and tissue regeneration. By overcoming the limitations of traditional administration methods, microneedle patches enable targeted therapy for deteriorated tissues. The design of these patches extends beyond the selection of needle tip material and biomacromolecule encapsulated drugs; it can also incorporate near-infrared rays to facilitate cascade reactions and treat diabetic wounds. In this review, we comprehensively summarize the advantages of microneedle patches compared to traditional treatment methods. We focus on the design and mechanism of these patches based on existing experimental articles in the field and discuss the potential for future research on microneedle patches.

The mechanism of Chebulae Fructus Immaturus promote diabetic wound healing based on network pharmacology and experimental verification

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic ulcers (DUs) are commonly seen in the lower limbs, especially the feet. Long-term hyperglycaemia in diabetic patients may cause peripheral microvascular damage, which affects local blood flow reconstruction when the skin is ruptured. This results in delayed or even non-healing of skin wounds. Chebulae Fructus Immaturus (CFI) is a traditional Chinese medicine. According to traditional Chinese medicine theory, CFI belongs to the lung channel and large intestine channel. Clinical data confirm a significant clinical effect of CFI in the treatment of skin diseases. CFI can be safely used to treat wounds due to its natural active ingredients.

AIM OF THE STUDY

This study utilised HPLC-ESI-QTOF-MS/MS combined with network pharmacology to investigate the mechanism of Chebulae Fructus Immaturus extract (CFIE) in the treatment of DU. Moreover, the efficacy of CFIE on DU was verified in vitro and in vivo by constructing cell models and mouse models.

MATERIALS AND METHODS

The main ingredients of CFIE were identified by HPLC-ESI-QTOF-MS/MS. The targets of these ingredients were predicted by database analysis and intersected with the DU targets. Gene ontology (GO) was used for functional enrichment of differential genes, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) was used for enrichment of signalling pathways related to the differential genes. The network pharmacology findings were validated in vivo and in vitro, and the affinity of key targets and active components was assessed using molecular docking.

RESULTS

Twenty-nine compounds of CFIE were identified by HPLC-ESI-QTOF-MS/MS, and their potential targets were predicted. Among these, 41 targets were associated with DU. KEGG enrichment analysis showed that the PI3K/AKT and HIF-1α signalling pathways were significantly enriched, which may be related to the promotion of wound angiogenesis. In vitro cell experiments showed that CFIE promoted the proliferation, migration and angiogenesis of HUVECs, and also affected the expression of pathway-related proteins. In vivo experiments showed that CFIE increased the expression of pathway-related proteins in wound tissue and promoted the formation of blood vessels.

CONCLUSIONS

In summary, this study systematically demonstrated the possible therapeutic effects and mechanisms of CFIE on DU through network pharmacology analysis and experimental verification. The results revealed that CFIE can accelerate the angiogenesis of diabetic wounds through the PI3K/AKT and HIF-1α signalling pathways, ultimately promoting the healing of diabetic wounds.

Effect of extracellular matrices on production and potency of mesenchymal stem cell-derived exosomes

Mesenchymal stem cell (MSC) derived exosomes have emerged as potential acellular therapeutics for various tissue regenerative applications. However, successful clinical translation of exosome-based therapy is limited by lack of a structured production platform. Thus, in this study, the effect of decellularized extracellular matrix (dECM) was assessed on the production and potency of exosomes secreted by bone marrow-derived human MSCs. The results indicate that there was a ∼2-fold increase in MSC-exosome production when MSCs were cultured on dECM compared to TCP. Further, our study revealed that dECM generation induced by ascorbic acid (AA) up to 100 µg mL-1 highly increased exosome yield thereby indicating a potential scale up method for MSC exosome production. The bioactivity of exosomes was investigated by their ability to improve the healing of wounded human skin explants. Wound closure was enhanced in the presence of exosomes isolated from MSCs cultured on ascorbic acid-induced dECM compared to TCP generated MSC-exosomes. In summary, this study suggests a promising solution to a major bottleneck in large-scale production of MSC exosomes for cell-free therapy.

Standardized GMP-Compliant Scalable 3D-Bioprocessing of Epidermal Stem Cells for Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) pose a significant threat to the health and well-being of individuals with diabetes, often leading to lower limb amputations. Fortunately, epidermal stem cell therapy offers hope for improving the treatment of DFUs. By leveraging 3D culture techniques, the scalability of stem cell manufacturing can be greatly enhanced. In particular, using bioactive materials and scaffolds can promote the healing potential of cells, enhance their proliferation, and facilitate their survival. Furthermore, 3D tissue-mimicking cultures can accurately replicate the complex interactions between cells and extracellular matrix, thereby ensuring that the stem cells are primed for therapeutic application. To ensure the safety and quality of these stem cells, it is essential to adhere to good manufacturing practice (GMP) principles during cultivation. This chapter provides a comprehensive overview of the step-by-step process for GMP-based 3D epidermal stem cell cultivation, thus laying the groundwork for developing reliable regenerative medicine therapies.

Preclinical study of diabetic foot ulcers: From pathogenesis to vivo/vitro models and clinical therapeutic transformation

Diabetic foot ulcer (DFU), a common intractable chronic complication of diabetes mellitus (DM), has a prevalence of up to 25%, with more than 17% of the affected patients at risk of amputation or even death. Vascular risk factors, including vascular stenosis or occlusion, dyslipidemia, impaired neurosensory and motor function, and skin infection caused by trauma, all increase the risk of DFU in patients with diabetes. Therefore, diabetic foot is not a single pathogenesis. Preclinical studies have contributed greatly to the pathogenesis determination and efficacy evaluation of DFU. Many therapeutic tools are currently being investigated using DFU animal models for effective clinical translation. However, preclinical animal models that completely mimic the pathogenesis of DFU remain unexplored. Therefore, in this review, the preparation methods and evaluation criteria of DFU animal models with three major pathological mechanisms: neuropathy, angiopathy and DFU infection were discussed in detail. And the advantages and disadvantages of various DFU animal models for clinical sign simulation. Furthermore, the current status of vitro models of DFU and some preclinical studies have been transformed into clinical treatment programs, such as medical dressings, growth factor therapy, 3D bioprinting and pre-vascularization, Traditional Chinese Medicine treatment. However, because of the complexity of the pathological mechanism of DFU, the clinical transformation of DFU model still faces many challenges. We need to further optimize the existing preclinical studies of DFU to provide an effective animal platform for the future study of pathophysiology and clinical treatment of DFU.

Exosomes: New Insights into the Pathogenesis of Metabolic Syndrome

Exosomes are a subtype of extracellular vesicles (EVs) with a diameter of 30~150 nm (averaging ~100 nm) that are primarily produced through the endosomal pathway, and carry various components such as lipids, proteins, RNA, and other small molecular substances. Exosomes can mediate intercellular communication through the bioactive substances they carry, thus participating in different physiological activities. Metabolic syndrome (MS) is a disease caused by disturbances in the body's metabolism, mainly including insulin resistance (IR), diabetes, obesity, non-alcoholic fatty liver disease (NAFLD), hyperlipidemia, and atherosclerosis (AS). Recent studies have shown that exosomes are closely related to the occurrence and development of MS. Exosomes can act as messengers to mediate signaling transductions between metabolic cells in the organism and play a bidirectional regulatory role in the MS process. This paper mainly reviews the components, biogenesis, biological functions and potential applications of exosomes, and exosomes involved in the pathogenesis of MS as well as their clinical significance in MS diagnosis.

The physiological phenomenon and regulation of macrophage polarization in diabetic wound

Macrophages play a crucial role in regulating wound healing, as they undergo a transition from the proinflammatory M1 phenotype to the proliferative M2 phenotype, ultimately contributing to a favorable outcome. However, in hyperglycemic and hyper-reactive oxygen species environments, the polarization of macrophages becomes dysregulated, hindering the transition from the inflammatory to proliferative phase and consequently delaying the wound healing process. Consequently, regulating macrophage polarization is often regarded as a potential target for the treatment of diabetic wounds. The role of macrophages in wound healing and the changes in macrophages in diabetic conditions were discussed in this review. After that, we provide a discussion of recent therapeutic strategies for diabetic wounds that utilize macrophage polarization. Furthermore, this review also provides a comprehensive summary of the efficacious treatment strategies aimed at enhancing diabetic wound healing through the regulation of macrophage polarization. By encompassing a thorough understanding of the fundamental principles and their practical implementation, the advancement of treatment strategies for diabetic wounds can be further facilitated.

Exosomes: Potential key players towards novel therapeutic options in diabetic wounds

Diabetic wounds are usually difficult to heal, and wounds in foot in particular are often aggravated by infection, trauma, diabetic neuropathy, peripheral vascular disease and other factors, resulting in serious foot ulcers. The pathogenesis and clinical manifestations of diabetic wounds are complicated, and there is still a lack of objective and in-depth laboratory diagnosis and classification standards. Exosomes are nanoscale vesicles containing DNA, mRNA, microRNA, cyclic RNA, metabolites, lipids, cytoplasm and cell surface proteins, etc., which are involved in intercellular communication and play a crucial role in vascular regeneration, tissue repair and inflammation regulation in the process of diabetic wound healing. Here, we discussed exosomes of different cellular origins, such as diabetic wound-related fibroblasts (DWAF), adipose stem cells (ASCs), mesenchymal stem cells (MSCs), immune cells, platelets, human amniotic epithelial cells (hAECs), epidermal stem cells (ESCs), and their various molecular components. They exhibit multiple therapeutic effects during diabetic wound healing, including promoting cell proliferation and migration associated with wound healing, regulating macrophage polarization to inhibit inflammatory responses, promoting nerve repair, and promoting vascular renewal and accelerating wound vascularization. In addition, exosomes can be designed to deliver different therapeutic loads and have the ability to deliver them to the desired target. Therefore, exosomes may become an innovative target for precision therapeutics in diabetic wounds. In this review, we summarize the latest research on the role of exosomes in the healing of diabetic wound by regulating the pathogenesis of diabetic wounds, and discuss their potential applications in the precision treatment of diabetic wounds.

The mechanisms of exosomes in diabetic foot ulcers healing: a detailed review

As time goes by, the morbidity of diabetes mellitus continues to rise, and the economic burden of diabetic foot ulcers as a common and serious complication of diabetes is increasing. However, currently there is no unified clinical treatment strategy for this complication, and the therapeutic efficacy is unsatisfactory. Recent studies have revealed that biological effects of exosomes involved in multiple stages of the process of wound closure are similar to source cells. Compared with source cells, exosomes possess lowly immunogenicity, highly stability and easily stored, etc. Accumulating evidence confirmed that exosomes promote diabetic wound healing through various pathways such as promoting angiogenesis, collagen fiber deposition, and inhibiting inflammation. The superior therapeutic efficacy of exosomes in accelerating diabetic cutaneous wound healing has attracted an increasing attention. Notably, the molecular mechanisms of exosomes vary among different sources in the chronic wound closure of diabetes. This review focuses on the specific roles and mechanisms of different cell- or tissue-derived exosomes relevant to wound healing. Additionally, the paper provides an overview of the current pre-clinical and clinical applications of exosomes, illustrates their special advantages in wound repair. Furthermore, we discuss the potential obstacles and various solutions for future research on exosomes in the management of diabetic foot ulcer. The aim is to offer novel insights and approaches for the treatment of diabetic foot ulcer.

Electrostatically assembled wound dressings deliver pro-angiogenic anti-miRs preferentially to endothelial cells

Chronic non-healing wounds occur frequently in individuals affected by diabetes, yet standard-of-care treatment leaves many patients inadequately treated or with recurring wounds. MicroRNA (miR) expression is dysregulated in diabetic wounds and drives an anti-angiogenic phenotype, but miRs can be inhibited with short, chemically-modified RNA oligonucleotides (anti-miRs). Clinical translation of anti-miRs is hindered by delivery challenges such as rapid clearance and uptake by off-target cells, requiring repeated injections, excessively large doses, and bolus dosing mismatched to the dynamics of the wound healing process. To address these limitations, we engineered electrostatically assembled wound dressings that locally release anti-miR-92a, as miR-92a is implicated in angiogenesis and wound repair. In vitro, anti-miR-92a released from these dressings was taken up by cells and inhibited its target. An in vivo cellular biodistribution study in murine diabetic wounds revealed that endothelial cells, which play a critical role in angiogenesis, exhibit higher uptake of anti-miR eluted from coated dressings than other cell types involved in the wound healing process. In a proof-of-concept efficacy study in the same wound model, anti-miR targeting anti-angiogenic miR-92a de-repressed target genes, increased gross wound closure, and induced a sex-dependent increase in vascularization. Overall, this proof-of-concept study demonstrates a facile, translational materials approach for modulating gene expression in ulcer endothelial cells to promote angiogenesis and wound healing. Furthermore, we highlight the importance of probing cellular interactions between the drug delivery system and the target cells to drive therapeutic efficacy.

Novel neutrophil extracellular trap-related mechanisms in diabetic wounds inspire a promising treatment strategy with hypoxia-challenged small extracellular vesicles

Neutrophil extracellular traps (NETs) have been considered a significant unfavorable factor for wound healing in diabetes, but the mechanisms remain unclear. The therapeutic application of small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) has received considerable attention for their properties. Hypoxic preconditioning is reported to enhance the therapeutic potential of MSC-derived sEVs in regenerative medicine. Therefore, the aim of this study is to illustrate the detailed mechanism of NETs in impairment of diabetic wound healing and develop a promising NET-targeting treatment based on hypoxic pretreated MSC-derived sEVs (Hypo-sEVs). Excessive NETs were found in diabetic wounds and in high glucose (HG)-induced neutrophils. Further research showed that high concentration of NETs impaired the function of fibroblasts through activating endoplasmic reticulum (ER) stress. Hypo-sEVs efficiently promoted diabetic wound healing and reduced the excessive NET formation by transferring miR-17-5p. Bioinformatic analysis and RNA interference experiment revealed that miR-17-5p in Hypo-sEVs obstructed the NET formation by targeting TLR4/ROS/MAPK pathway. Additionally, miR-17-5p overexpression decreased NET formation and overcame NET-induced impairment in fibroblasts, similar to the effects of Hypo-sEVs. Overall, we identify a previously unrecognized NET-related mechanism in diabetic wounds and provide a promising NET-targeting strategy for wound treatment.

Mesenchymal stem cell-derived extracellular vesicles in skin wound healing: roles, opportunities and challenges

Skin wounds are characterized by injury to the skin due to trauma, tearing, cuts, or contusions. As such injuries are common to all human groups, they may at times represent a serious socioeconomic burden. Currently, increasing numbers of studies have focused on the role of mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) in skin wound repair. As a cell-free therapy, MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy. Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures, including the regeneration of vessels, nerves, and hair follicles. In addition, MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization, wound angiogenesis, cell proliferation, and cell migration, and by inhibiting excessive extracellular matrix production. Additionally, these structures can serve as a scaffold for components used in wound repair, and they can be developed into bioengineered EVs to support trauma repair. Through the formulation of standardized culture, isolation, purification, and drug delivery strategies, exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair. In conclusion, MSC-derived EVs-based therapies have important application prospects in wound repair. Here we provide a comprehensive overview of their current status, application potential, and associated drawbacks.

Therapeutic Potential of Extracellular Vesicles from Different Stem Cells in Chronic Wound Healing

Wound healing has long been a complex problem, especially in chronic wounds. Although debridement, skin grafting, and antimicrobial dressings have been used to treat chronic wounds, their treatment period is long, expensive, and has specific rejection reactions. The poor treatment results of traditional methods have caused psychological stress to patients and a substantial economic burden to society. Extracellular vesicles (EVs) are nanoscale vesicles secreted by cells. They play an essential role in intercellular communication. Numerous studies have confirmed that stem cell-derived extracellular vesicles (SC-EVs) can inhibit overactive inflammation, induce angiogenesis, promote re-epithelization, and reduce scar formation. Therefore, SC-EVs are expected to be a novel cell-free strategy for chronic wound treatment. We first summarize the pathological factors that hinder wound healing and discuss how SC-EVs accelerate chronic wound repair. And then, we also compare the advantages and disadvantages of different SC-EVs for chronic wound treatment. Finally, we discuss the limitations of SC-EVs usage and provide new thoughts for future SC-EVs research in chronic wound treatment.

Advancements and Insights in Exosome-Based Therapies for Wound Healing: A Comprehensive Systematic Review (2018-June 2023)

Exosomes have shown promising potential as a therapeutic approach for wound healing. Nevertheless, the translation from experimental studies to commercially available treatments is still lacking. To assess the current state of research in this field, a systematic review was performed involving studies conducted and published over the past five years. A PubMed search was performed for English-language, full-text available papers published from 2018 to June 2023, focusing on exosomes derived from mammalian sources and their application in wound healing, particularly those involving in vivo assays. Out of 531 results, 148 papers were selected for analysis. The findings revealed that exosome-based treatments improve wound healing by increasing angiogenesis, reepithelization, collagen deposition, and decreasing scar formation. Furthermore, there was significant variability in terms of cell sources and types, biomaterials, and administration routes under investigation, indicating the need for further research in this field. Additionally, a comparative examination encompassing diverse cellular origins, types, administration pathways, or biomaterials is imperative. Furthermore, the predominance of rodent-based animal models raises concerns, as there have been limited advancements towards more complex in vivo models and scale-up assays. These constraints underscore the substantial efforts that remain necessary before attaining commercially viable and extensively applicable therapeutic approaches using exosomes.

Stem cell-derived exosomes: emerging therapeutic opportunities for wound healing

Wound healing is a dynamic and highly sequential process involving a series of overlapping spatial and temporal phases, including hemostasis, inflammation, proliferation, and tissue remodeling. Mesenchymal stem cells (MSCs) are multipotent stem cells with self-renewal, multidirectional differentiation potential, and paracrine regulation. Exosomes are subcellular vesicular components 30-150 nm in size and are novel carriers of intercellular communication in regulating the biological behaviors of skin cells. Compared to MSCs, MSC-derived exosomes (MSC-exos) possess lower immunogenicity, easy storage, and highly effective biological activity. MSC-exos, mainly derived from adipose-derived stem cells (ADSCs), bone marrow-derived MSCs (BMSCs), human umbilical cord MSCs (hUC-MSCs), and other stem cell types, play a role in shaping the activity of fibroblasts, keratinocytes, immune cells, and endothelial cells in diabetic wounds, inflammatory wound repair, and even wound-related keloid formation. Therefore, this study focuses on the specific roles and mechanisms of different MSC-exos in wound healing, as well as the current limitations and various perspectives. Deciphering the biological properties of MSC-exos is crucial to providing a promising cell-free therapeutic tool for wound healing and cutaneous regeneration.

Advanced polymer hydrogels that promote diabetic ulcer healing: mechanisms, classifications, and medical applications

Diabetic ulcers (DUs) are one of the most serious complications of diabetes mellitus. The application of a functional dressing is a crucial step in DU treatment and is associated with the patient's recovery and prognosis. However, traditional dressings with a simple structure and a single function cannot meet clinical requirements. Therefore, researchers have turned their attention to advanced polymer dressings and hydrogels to solve the therapeutic bottleneck of DU treatment. Hydrogels are a class of gels with a three-dimensional network structure that have good moisturizing properties and permeability and promote autolytic debridement and material exchange. Moreover, hydrogels mimic the natural environment of the extracellular matrix, providing suitable surroundings for cell proliferation. Thus, hydrogels with different mechanical strengths and biological properties have been extensively explored as DU dressing platforms. In this review, we define different types of hydrogels and elaborate the mechanisms by which they repair DUs. Moreover, we summarize the pathological process of DUs and review various additives used for their treatment. Finally, we examine the limitations and obstacles that exist in the development of the clinically relevant applications of these appealing technologies. This review defines different types of hydrogels and carefully elaborate the mechanisms by which they repair diabetic ulcers (DUs), summarizes the pathological process of DUs, and reviews various bioactivators used for their treatment.

Mechanisms of diabetic foot ulceration: A review

Diabetic foot ulcers (DFUs) are associated with complex pathogenic factors and are considered a serious complication of diabetes. The potential mechanisms underlying DFUs have been increasingly investigated. Previous studies have focused on the three aspects of diabetic peripheral vascular disease, neuropathy, and wound infections. With advances in technology, researchers have been gradually conducting studies using immune cells, endothelial cells, keratinocytes, and fibroblasts, as they are involved in wound healing. It has been reported that the upregulation or downregulation of molecular signaling pathways is essential for the healing of DFUs. With a recent increase in the awareness of epigenetics, its regulatory role in wound healing has become a much sought-after trend in the treatment of DFUs. This review focuses on four aspects involved in the pathogenesis of DFUs: physiological and pathological mechanisms, cellular mechanisms, molecular signaling pathway mechanisms, and epigenetics. Given the challenge in the treatment of DFUs, we are hopeful that our review will provide new ideas for peers.

Removing the stumbling block of exosome applications in clinical and translational medicine: expand production and improve accuracy

Although the clinical application and transformation of exosomes are still in the exploration stage, the prospects are promising and have a profound impact on the future transformation medicine of exosomes. However, due to the limitation of production and poor targeting ability of exosomes, the extensive and rich biological functions of exosomes are restricted, and the potential of clinical transformation is limited. The current research is committed to solving the above problems and expanding the clinical application value, but it lacks an extensive, multi-angle, and comprehensive systematic summary and prospect. Therefore, we reviewed the current optimization strategies of exosomes in medical applications, including the exogenous treatment of parent cells and the improvement of extraction methods, and compared their advantages and disadvantages. Subsequently, the targeting ability was improved by carrying drugs and engineering the structure of exosomes to solve the problem of poor targeting ability in clinical transformation. In addition, we discussed other problems that may exist in the application of exosomes. Although the clinical application and transformation of exosomes are still in the exploratory stage, the prospects are promising and have a profound impact on drug delivery, clinical diagnosis and treatment, and regenerative medicine.

Cellular rejuvenation: molecular mechanisms and potential therapeutic interventions for diseases

The ageing process is a systemic decline from cellular dysfunction to organ degeneration, with more predisposition to deteriorated disorders. Rejuvenation refers to giving aged cells or organisms more youthful characteristics through various techniques, such as cellular reprogramming and epigenetic regulation. The great leaps in cellular rejuvenation prove that ageing is not a one-way street, and many rejuvenative interventions have emerged to delay and even reverse the ageing process. Defining the mechanism by which roadblocks and signaling inputs influence complex ageing programs is essential for understanding and developing rejuvenative strategies. Here, we discuss the intrinsic and extrinsic factors that counteract cell rejuvenation, and the targeted cells and core mechanisms involved in this process. Then, we critically summarize the latest advances in state-of-art strategies of cellular rejuvenation. Various rejuvenation methods also provide insights for treating specific ageing-related diseases, including cellular reprogramming, the removal of senescence cells (SCs) and suppression of senescence-associated secretory phenotype (SASP), metabolic manipulation, stem cells-associated therapy, dietary restriction, immune rejuvenation and heterochronic transplantation, etc. The potential applications of rejuvenation therapy also extend to cancer treatment. Finally, we analyze in detail the therapeutic opportunities and challenges of rejuvenation technology. Deciphering rejuvenation interventions will provide further insights into anti-ageing and ageing-related disease treatment in clinical settings.

Analysis of miR-203a-3p/SOCS3-mediated induction of M2 macrophage polarization to promote diabetic wound healing based on epidermal stem cell-derived exosomes

BACKGROUND

The development of therapeutic strategies to improve wound healing in individual diabetic patients remains challenging. Stem cell-derived exosomes represent a promising nanomaterial, and microRNAs (miRNAs) can be isolated from them. It is important to identify the potential therapeutic role of specific miRNAs, given that miRNAs can play a therapeutic role.

METHODS

qPCR, flow cytometry, and western blotting were used to verify the effect of epidermal stem cell-derived exosomes (EpiSC-EXOs) on M2 macrophage polarization and SOCS3 expression. By screening key miRNAs targeting SOCS3 in EpiSC-EXOs by high-throughput sequencing, we verified the mechanism in vitro. Finally, an animal model was used to verify the effect of promoting healing.

RESULTS

The use of EpiSC-EXOs reduced SOCS3 expression and promoted M2 macrophage polarization. The abundant miR-203a-3p present in the EpiSC-EXOs specifically bound to SOCS3 and activated the JAK2/STAT3 signaling pathway to induce M2 macrophage polarization. Treatment of the db/db mouse wound model with miR-203a-3p agomir exerted a pro-healing effect.

CONCLUSIONS

Our results demonstrated that the abundant miR-203a-3p present in EpiSC-EXOs can promote M2 macrophage polarization by downregulating SOCS3 and suggested that diabetic wounds can obtain better healing effects through this mechanism.

Loading Nanoceria Improves Extracellular Vesicle Membrane Integrity and Therapy to Wounds in Aged Mice

Wound healing is a programmed process through which tissue restores its integrity after an injury. Advancing age is a risk factor for delayed cutaneous wound healing; however, ideal therapeutic approaches for aged wound have not been developed yet. By dissecting the harsh microenvironment of aged wound, we propose an integrated chemical and biological strategy to mitigate two main hostile factors including oxidative stress and ischemia. Mesenchymal stem cell-derived extracellular vesicles (EVs) are a rising star in regenerative medicine due to their powerful facilitation in tissue repair and regeneration. However, the fragile lipid membrane limits their function under the oxidative stress microenvironment. Nanoceria is an antioxidative nanozyme; here, we reveal that nanoceria-loaded EVs derived from mesenchymal stem cells facilitate cutaneous wound healing in aged mice. DG-CeO₂ was prepared via coating CeO₂ covalently with d-glucose to promote their cellular endocytosis. DG-CeO₂ was packaged into EVs under optimized hypoxic conditions (DG-CeO₂ EVs^Hyp). We further demonstrated that DG-CeO₂ EVs^Hyp had favorable biocompatibility and antioxidative and proangiogenic effects during the cutaneous wound healing in both young and aged mice. Further evidence revealed that DG-CeO₂ EVs^Hyp-transferred miR-92a-3p/125b-5p and their targets associated with aging degeneration may be the potential mechanisms. Collectively, these findings highlight that nanoceria-loaded EVs released by engineered stem cells may represent a potential therapeutic approach for tissue regeneration in aged population.

Future applications of exosomes delivering resolvins and cytokines in facilitating diabetic foot ulcer healing

Type 2 diabetes mellitus (T2DM) increases the risk of many lethal and debilitating conditions. Among them, foot ulceration due to neuropathy, vascular disease, or trauma affects the quality of life of millions in the United States and around the world. Physiological wound healing is stalled in the inflammatory phase by the chronicity of inflammation without proceeding to the resolution phase. Despite advanced treatment, diabetic foot ulcers (DFUs) are associated with a risk of amputation. Thus, there is a need for novel therapies to address chronic inflammation, decreased angiogenesis, and impaired granulation tissue formation contributing to the non-healing of DFUs. Studies have shown promising results with resolvins (Rv) and anti-inflammatory therapies that resolve inflammation and enhance tissue healing. But many of these studies have encountered difficulty in the delivery of Rv in terms of efficiency, tissue targetability, and immunogenicity. This review summarized the perspective of optimizing the therapeutic application of Rv and cytokines by pairing them with exosomes as a novel strategy for targeted tissue delivery to treat non-healing chronic DFUs. The articles discussing the T2DM disease state, current research on Rv for treating inflammation, the role of Rv in enhancing wound healing, and exosomes as a delivery vehicle were critically reviewed to find support for the proposition of using Rv and exosomes in combination for DFUs therapy. The literature reviewed suggests the beneficial role of Rv and exosomes and exosomes loaded with anti-inflammatory agents as promising therapeutic agents in ulcer healing.

Recent advances of the nanocomposite hydrogel as a local drug delivery for diabetic ulcers

Diabetic ulcer is a serious complication of diabetes. Compared with that of healthy people, the skin of patients with a diabetic ulcer is more easily damaged and difficult to heal. Without early intervention, the disease will become increasingly serious, often leading to amputation or even death. Most current treatment methods cannot achieve a good wound healing effect. Numerous studies have shown that a nanocomposite hydrogel serves as an ideal drug delivery method to promote the healing of a diabetic ulcer because of its better drug loading capacity and stability. Nanocomposite hydrogels can be loaded with one or more drugs for application to chronic ulcer wounds to promote rapid wound healing. Therefore, this paper reviews the latest progress of delivery systems based on nanocomposite hydrogels in promoting diabetic ulcer healing. Through a review of the recent literature, we put forward the shortcomings and improvement strategies of nanocomposite hydrogels in the treatment of diabetic ulcers.

Stem Cells and Angiogenesis: Implications and Limitations in Enhancing Chronic Diabetic Foot Ulcer Healing

Nonhealing diabetic foot ulcers (DFUs) are a continuing clinical issue despite the improved treatment with wound debridement, off-loading the ulcer, medication, wound dressings, and preventing infection by keeping the ulcer clean. Wound healing is associated with granulation tissue formation and angiogenesis favoring the wound to enter the resolution phase of healing followed by healing. However, chronic inflammation and reduced angiogenesis in a hyperglycemic environment impair the normal healing cascade and result in chronically non-healing diabetic foot ulcers. Promoting angiogenesis is associated with enhanced wound healing and using vascular endothelial growth factors has been proven beneficial to promote neo-angiogenesis. However, still, nonhealing DFUs persist with increased risks of amputation. Regenerative medicine is an evolving branch applicable in wound healing with the use of stem cells to promote angiogenesis. Various studies have reported promising results, but the associated limitations need in-depth research. This article focuses on summarizing and critically reviewing the published literature since 2021 on the use of stem cells to promote angiogenesis and enhance wound healing in chronic non-healing DFUs.

The Emerging Role of Immune Cells and Targeted Therapeutic Strategies in Diabetic Wounds Healing

Poor wound healing in individuals with diabetes has long plagued clinicians, and immune cells play key roles in the inflammation, proliferation and remodeling that occur in wound healing. When skin integrity is damaged, immune cells migrate to the wound bed through the actions of chemokines and jointly restore tissue homeostasis and barrier function by exerting their respective biological functions. An imbalance of immune cells often leads to ineffective and disordered inflammatory responses. Due to the maladjusted microenvironment, the wound is unable to smoothly transition to the proliferation and remodeling stage, causing it to develop into a chronic refractory wound. However, chronic refractory wounds consistently lead to negative outcomes, such as long treatment cycles, high hospitalization rates, high medical costs, high disability rates, high mortality rates, and many adverse consequences. Therefore, strategies that promote the rational distribution and coordinated development of immune cells during wound healing are very important for the treatment of diabetic wounds (DW). Here, we explored the following aspects by performing a literature review: 1) the current situation of DW and an introduction to the biological functions of immune cells; 2) the role of immune cells in DW; and 3) existing (or undeveloped) therapies targeting immune cells to promote wound healing to provide new ideas for basic research, clinical treatment and nursing of DW.