Differential Therapeutic Effect of Extracellular Vesicles Derived by Bone Marrow and Adipose Mesenchymal Stem Cells on Wound Healing of Diabetic Ulcers and Correlation to Their Cargoes

Direct and cell-mediated EV-ECM interplay

Extracellular vesicles (EV) are a heterogeneous group of lipid particles excreted by cells. They play an important role in regeneration, development, inflammation, and cancer progression, together with the extracellular matrix (ECM), which they constantly interact with. In this review, we discuss direct and indirect interactions of EVs and the ECM and their impact on different physiological processes. The ECM affects the secretion of EVs, and the properties of the ECM and EVs modulate EVs' diffusion and adhesion. On the other hand, EVs can affect the ECM both directly through enzymes and indirectly through the modulation of the ECM synthesis and remodeling by cells. This review emphasizes recently discovered types of EVs bound to the ECM and isolated by enzymatic digestion, including matrix-bound nanovesicles (MBV) and tissue-derived EV (TiEV). In addition to the experimental studies, computer models of the EV-ECM-cell interactions, from all-atom models to quantitative pharmacology models aiming to improve our understanding of the interaction mechanisms, are also considered. STATEMENT OF SIGNIFICANCE: Application of extracellular vesicles in tissue engineering is an actively developing area. Vesicles not only affect cells themselves but also interact with the matrix and change it. The matrix also influences both cells and vesicles. In this review, different possible types of interactions between vesicles, matrix, and cells are discussed. Furthermore, the united EV-ECM system and its regulation through the cellular activity are presented.

Advantages and disadvantages of various hydrogel scaffold types: A research to improve the clinical conversion rate of loaded MSCs-Exos hydrogel scaffolds

Mesenchymal stem cell-derived exosomes(MSCs-Exos) offer promising therapeutic potential for a wide range of tissues and organs such as bone/cartilage, nerves, skin, fat, and endocrine organs. In comparison to the application of mesenchymal stem cells (MSCs), MSCs-Exos address critical challenges related to rejection reactions and ethical concerns, positioning themselves as a promising cell-free therapy. As exosomes are extracellular vesicles, their effective delivery necessitates the use of carriers. Consequently, the selection of hydrogel materials as scaffolds for exosome delivery has become a focal point of contemporary research. The diversity of hydrogel scaffolds, which can take various forms such as injectable types, dressings, microneedles, and capsules, leads to differing choices among researchers for treating diseases within the same domain. This variability in hydrogel materials poses challenges for the translation of findings into clinical practice. The review highlights the potential of hydrogel-loaded exosomes in different fields and introduces the advantages and disadvantages of different forms of hydrogel applications. It aims to provide a multifunctional and highly recognized hydrogel scaffold option for tissue regeneration at specific sites, improve clinical translation efficiency, and benefit the majority of patients.

Mesenchymal stem cell-derived extracellular vesicles in joint diseases: Therapeutic effects and underlying mechanisms

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

Therapeutic application of mesenchymal stem cell-derived exosomes in skin wound healing

Wound healing is a complicated obstacle, especially for chronic wounds. Mesenchymal stem cell-derived exosomes may be a promising cell-free approach for treating skin wound healing. Exosomes can accelerate wound healing by attenuating inflammation, promoting angiogenesis, cell proliferation, extracellular matrix production and remodeling. However, many issues, such as off-target effects and high degradation of exosomes in wound sites need to be addressed before applying into clinical therapy. Therefore, the bioengineering technology has been introduced to modify exosomes with greater stability and specific therapeutic property. To prolong the function time and the local concentration of exosomes in the wound bed, the use of biomaterials to load exosomes emerges as a promising strategy. In this review, we summarize the biogenesis and characteristics of exosomes, the role of exosomes in wound healing, and the therapeutic applications of modified-exosomes in wound healing. The challenges and prospects of exosomes in wound healing are also discussed.

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.

From stem cells to extracellular vesicles: a new horizon in tissue engineering and regenerative medicine

In the fields of tissue engineering and regenerative medicine, extracellular vesicles (EVs) have become viable therapeutic tools. EVs produced from stem cells promote tissue healing by regulating the immune system, enhancing cell proliferation and aiding remodeling processes. Recently, EV has gained significant attention from researchers due to its ability to treat various diseases. Unlike stem cells, stem cell-derived EVs show lower immunogenicity, are less able to overcome biological barriers, and have a higher safety profile. This makes the use of EVs derived from cell-free stem cells a promising alternative to whole-cell therapy. This review focuses on the biogenesis, isolation, and characterization of EVs and highlights their therapeutic potential for bone fracture healing, wound healing, and neuronal tissue repair and treatment of kidney and intestinal diseases. Additionally, this review discusses the potential of EVs for the treatment of cancer, COVID-19, and HIV. In summary, the use of EVs derived from stem cells offers a new horizon for applications in tissue engineering and regenerative medicine.

Mesenchymal stromal/stem cell tissue source and in vitro expansion impact extracellular vesicle protein and miRNA compositions as well as angiogenic and immunomodulatory capacities

Recently, therapies utilizing extracellular vesicles (EVs) derived from mesenchymal stromal/stem cells (MSCs) have begun to show promise in clinical trials. However, EV therapeutic potential varies with MSC tissue source and in vitro expansion through passaging. To find the optimal MSC source for clinically translatable EV-derived therapies, this study aims to compare the angiogenic and immunomodulatory potentials and the protein and miRNA cargo compositions of EVs isolated from the two most common clinical sources of adult MSCs, bone marrow and adipose tissue, across different passage numbers. Primary bone marrow-derived MSCs (BMSCs) and adipose-derived MSCs (ASCs) were isolated from adult female Lewis rats and expanded in vitro to the indicated passage numbers (P2, P4, and P8). EVs were isolated from the culture medium of P2, P4, and P8 BMSCs and ASCs and characterized for EV size, number, surface markers, protein content, and morphology. EVs isolated from different tissue sources showed different EV yields per cell, EV sizes, and protein yield per EV. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of proteomics data and miRNA seq data identified key proteins and pathways associated with differences between BMSC-EVs and ASC-EVs, as well as differences due to passage number. In vitro tube formation assays employing human umbilical vein endothelial cells suggested that both tissue source and passage number had significant effects on the angiogenic capacity of EVs. With or without lipopolysaccharide (LPS) stimulation, EVs more significantly impacted expression of M2-macrophage genes (IL-10, Arg1, TGFβ) than M1-macrophage genes (IL-6, NOS2, TNFα). By correlating the proteomics analyses with the miRNA seq analysis and differences observed in our in vitro immunomodulatory, angiogenic, and proliferation assays, this study highlights the trade-offs that may be necessary in selecting the optimal MSC source for development of clinical EV therapies.

Single and combined strategies for mesenchymal stem cell exosomes alleviate liver fibrosis: a systematic review and meta-analysis of preclinical animal models

Background: The efficacy of mesenchymal stem cells (MSCs) in treating liver fibrosis has been supported by various clinical studies. However, stem cell transplantation is limited in clinical application due to its low survival rate, low liver implantation rate, and possible carcinogenicity. Recently, there has been increasing interest in the use of MSC-exos due to their widespread availability, low immunogenicity, and non-carcinogenic properties. Numerous studies have demonstrated the potential of MSC-exos in treating liver fibrosis and preventing progression to end-stage liver disease. Objective: This study aimed to systematically investigate the efficacy of MSC-exos single administration in the treatment of hepatic fibrosis and the combined advantages of MSC-exos in combination with drug therapy (MSC-exos-drugs). Methods: Data sources included PubMed, Web of Science, Embase, and the Cochrane Library, which were built up to January 2024. The population, intervention, comparison, outcomes, and study design (PICOS) principle was used to screen the literature, and the quality of the literature was evaluated to assess the risk of bias. Finally, the data from each study's outcome indicators were extracted for a combined analysis. Results: After screening, a total of 18 papers (19 studies) were included, of which 12 involved MSC-exos single administration for the treatment of liver fibrosis and 6 involved MSC-exos-drugs for the treatment of liver fibrosis. Pooled analysis revealed that MSC-exos significantly improved liver function, promoted the repair of damaged liver tissue, and slowed the progression of hepatic fibrosis and that MSC-exos-drugs were more efficacious than MSC-exos single administration. Subgroup analyses revealed that the use of AD-MSC-exos resulted in more consistent and significant efficacy when MSC-exos was used to treat hepatic fibrosis. For MSC-exos-drugs, a more stable end result is obtained by kit extraction. Similarly, infusion through the abdominal cavity is more effective. Conclusion: The results suggest that MSC-exos can effectively treat liver fibrosis and that MSC-exos-drugs are more effective than MSC-exos single administration. Although the results of the subgroup analyses provide recommendations for clinical treatment, a large number of high-quality experimental validations are still needed. Systematic Review Registration: CRD42024516199.

Efficacy of MSC-derived small extracellular vesicles in treating type II diabetic cutaneous wounds: a systematic review and meta-analysis of animal models

Background

Small extracellular vesicles derived from mesenchymal stem cells (MSC-sEVs) have emerged as a promising therapy for treating type II diabetic cutaneous wounds. Currently, the evidence supporting the use of MSC-sEVs for treating diabetic skin wounds remains inconclusive and is limited to preclinical studies. To facilitate the clinical translation of cell-free therapy, conducting a comprehensive systematic review of preclinical studies assessing the efficacy of MSC-sEVs is imperative.

Methods

A systematic search was conducted on PubMed, Web of Science, Embase, and Cochrane Library databases until June 14, 2023, to identify studies that met our pre-established inclusion criteria. The outcome indicators comprised wound closure rate (primary outcome), neovascular density, re-epithelialization rate, collagen deposition, and inflammatory factors (secondary Outcomes). A fixed-effects model was employed in instances of low heterogeneity (I2<50%), while a random-effects model was utilized for high heterogeneity (I2≥50%). The risk of bias in animal studies was assessed using the SYRCLE tool.

Results

Twenty-one studies were included in this meta-analysis. Compared with the control group, MSC-sEVs were found to significantly facilitate the healing of cutaneous wounds in type II diabetic patients (standardized mean difference [SMD]=3.16, 95% confidence interval [CI]: 2.65 to 3.66, P<0.00001, I2 = 39%).

Conclusions

According to the meta-analysis of preclinical studies, MSC-sEVs show promising applications in promoting type II diabetic wound healing. As a result, translating these findings into clinical applications appears warranted.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023375467.

The Angiogenic Repertoire of Stem Cell Extracellular Vesicles: Demystifying the Molecular Underpinnings for Wound Healing Applications

Stem cells-derived extracellular vesicles (SC-EVs) have emerged as promising therapeutic agents for wound repair, recapitulating the biological effects of parent cells while mitigating immunogenic and tumorigenic risks. These EVs orchestrate wound healing processes, notably through modulating angiogenesis-a critical event in tissue revascularization and regeneration. This study provides a comprehensive overview of the multifaceted mechanisms underpinning the pro-angiogenic capacity of EVs from various stem cell sources within the wound microenvironment. By elucidating the molecular intricacies governing their angiogenic prowess, we aim to unravel the mechanistic repertoire underlying their remarkable potential to accelerate wound healing. Additionally, methods to enhance the angiogenic effects of SC-EVs, current limitations, and future perspectives are highlighted, emphasizing the significant potential of this rapidly advancing field in revolutionizing wound healing strategies.

Cellular In Vitro Responses Induced by Human Mesenchymal Stem/Stromal Cell-Derived Extracellular Vesicles Obtained from Suspension Culture

Mesenchymal stem/stromal cells (MSCs) and their extracellular vesicles (MSC-EVs) have been described to have important roles in tissue regeneration, including tissue repair, control of inflammation, enhancing angiogenesis, and regulating extracellular matrix remodeling. MSC-EVs have many advantages for use in regeneration therapies such as facility for dosage, histocompatibility, and low immunogenicity, thus possessing a lower possibility of rejection. In this work, we address the potential activity of MSC-EVs isolated from adipose-derived MSCs (ADMSC-EVs) cultured on cross-linked dextran microcarriers, applied to test the scalability and reproducibility of EV production. Isolated ADMSC-EVs were added into cultured human dermal fibroblasts (NHDF-1), keratinocytes (HaCat), endothelial cells (HUVEC), and THP-1 cell-derived macrophages to evaluate cellular responses (i.e., cell proliferation, cell migration, angiogenesis induction, and macrophage phenotype-switching). ADMSC viability and phenotype were assessed during cell culture and isolated ADMSC-EVs were monitored by nanotracking particle analysis, electron microscopy, and immunophenotyping. We observed an enhancement of HaCat proliferation; NHDF-1 and HaCat migration; endothelial tube formation on HUVEC; and the expression of inflammatory cytokines in THP-1-derived macrophages. The increased expression of TGF-β and IL-1β was observed in M1 macrophages treated with higher doses of ADMSC-EVs. Hence, EVs from microcarrier-cultivated ADMSCs are shown to modulate cell behavior, being able to induce skin tissue related cells to migrate and proliferate as well as stimulate angiogenesis and cause balance between pro- and anti-inflammatory responses in macrophages. Based on these findings, we suggest that the isolation of EVs from ADMSC suspension cultures makes it possible to induce in vitro cellular responses of interest and obtain sufficient particle numbers for the development of in vivo concept tests for tissue regeneration studies.

Timely Shaver Treatment Removes Chronic Tophaceous Mass Improve Surgical Outcomes

Background: Current treatments with urate-lowering therapy (ULT) are effective for most patients with gout. However, approximately 10% of these patients do not respond well to ULT and develop chronic tophus lesions. Objective: This study aimed to evaluate the efficacy of surgery involving the shaver technique against chronic tophus lesions. Methods: This single-center, retrospective cohort study included 217 patients who had cumulatively undergone 303 shaver-assisted procedures between 2002 and 2018. Surgical outcomes were assessed in terms of the length of hospital stay (LOS) and wound healing time. Results: LOS and wound healing time were longer in patients with a preoperative tophus infection and lower extremity lesions than in those without infection and with upper extremity lesions (respectively, LOS: 12.7 vs. 8.6 days; wound healing time: 22.7 vs. 16.3 days). However, factors such as age, sex, body mass index, renal function, or uricemia level exerted no significant effect on surgical outcomes. Conclusion: Surgery involving the shaver technique should be performed before tophus infection. Clinical outcomes tend to be better for upper extremity lesions than for lower extremity lesions.

Preclinical Therapeutic Efficacy of Extracellular Vesicles Derived from Adipose-Derived Mesenchymal Stromal/Stem Cells in Diabetic Wounds: a Systematic Review and Meta-Analysis

Extracellular vesicles isolated from adipose tissue-derived mesenchymal stromal/stem cells (ADSC-EVs) have demonstrated promising potential in wound healing treatment. To determine the therapeutic efficacy of ADSC-EVs for diabetic wounds in preclinical models, we performed a meta-analysis of available studies. PubMed and Embase were searched (to April 23, 2023). All full-text articles describing the therapeutic application of ADSC-EVs in diabetic wounds were included. Study outcomes were pooled using a random effects meta-analysis, including wound closure, angiogenesis, and collagen deposition. Other outcomes were only discussed descriptively. Seventy unique records were identified from our search; 20 full-text articles were included for qualitative analysis. Twelve studies were eligible for quantitative meta-analysis. The results showed that ADSC-EVs accelerated diabetic wound healing compared to controls with a large effect (standardized mean difference (SMD) 4.22, 95% confidence interval (CI) 3.07 to 5.36). The administration of ADSC-EVs also improved neovascularization (SMD 9.27, 95% CI 4.70 to 13.83) and collagen deposition (SMD 2.19, 95% CI 0.94 to 3.44), with a large effect. The risk of bias was unclear in all included studies. Conclusively, ADSC-EV is an effective treatment for diabetic wounds in preclinical trials, and it appears justified for transfer into the clinical field.

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.

Recent advances in the use of extracellular vesicles from adipose-derived stem cells for regenerative medical therapeutics

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.

A Minimally Invasive Surgical Procedure to Harvest Palate Periosteum as a Source of Mesenchymal Stromal/Stem Cells for Bone Tissue Engineering

The aim of this study is to validate a minimally invasive surgical procedure to harvest palate periosteum as a source of tissue for mesenchymal stromal/stem cells. We performed a standardized procedure to harvest the palate periosteum in ten subjects, which consisted of a 3 mm disposable punch and a Molt periosteal elevator to harvest a small full-thickness fragment of soft tissue at the hard palate area, between the upper bicuspids, 3 to 4 mm apical to the cement enamel junction. The one-third inner portion was fragmented, and following standard cell culture procedures, the adherent cells were cultured for three passages, after obtaining 70-90% confluence. Cell morphology analysis, flow cytometry analysis, and viability and osteogenic differentiation assays were performed. In all 10 cases, uneventful healing was observed, with no need for analgesic intake. The evaluation of cell morphology showed elongated spindle-shaped cells distributed in woven patterns. A high viability range was verified as well as an immunophenotype compatible with mesenchymal stem cell lineage. The differentiation assay showed the potential of the cells to differentiate into the osteogenic lineage. These results demonstrate that the minimally invasive proposed surgical technique is capable of supplying enough periosteum source tissue for stem cell culture and bone tissue engineering.

Bone marrow mesenchymal stem cell-derived extracellular vesicles promote corneal epithelial repair and suppress apoptosis via modulation of Caspase-3 in vitro

Corneal injuries are the major cause of blindness and visual impairment. Available treatments are limited by their efficacy and side effects. Mesenchymal stem cell-derived extracellular vesicles are presumed as functional equivalents and potential candidates for cell-free therapy. This study reports isolation and characterization of extracellular vesicles from human bone marrow mesenchymal stem cells and evaluates their role in mediating epithelial repair and apoptosis in cultured corneal epithelial cells through scratch assay, PCR, immunofluorescence, and flow cytometry in vitro. The isolated extracellular vesicles were spherical, < 150 nm in diameter, and characterized as CD9+, CD63+, CD81+, TSG101+, and Calnexin-. Further, these vesicles promoted corneal epithelial repair by enhancing proliferation and suppressed apoptosis by regulating the expression of BAD, P53, BCL-2, and cleaved CASPASE-3. Thus, our results suggest that BM-MSC-EVs might have the potential to be used for the treatment of injury-induced corneal epithelial defects. Clinical translation of this work would require further investigations.

Exosomes isolated from TNF-α-treated bone marrow mesenchymal stem cells ameliorate pelvic floor dysfunction in rats

Exosomes derived from bone marrow-derived mesenchymal stem cells (BMSCs) can alleviate the symptoms of pelvic floor dysfunction (PFD) in rats. However, the potential therapeutical effects of exosomes derived from BMSCs treated with tumour necrosis factor (TNF)-α on the symptoms of PFD in rats are unknown. Exosomes extracted from BMSCs treated with or without TNF-α were applied to treat PFD rats. Our findings revealed a significant elevation in interleukin (IL)-6 and TNF-α, and matrix metalloproteinase-2 (MMP2) levels in the vaginal wall tissues of patients with pelvic organ prolapse (POP) compared with the control group. Daily administration of exosomes derived from BMSCs, treated either with or without TNF-α (referred to as Exo and TNF-Exo), resulted in increased void volume and bladder void pressure, along with reduced peak bladder pressure and leak point pressure in PFD rats. Notably, TNF-Exo treatment demonstrated superior efficacy in restoring void volume, bladder void pressure and the mentioned parameters compared with Exo treatment. Importantly, TNF-Exo exhibited greater potency than Exo in restoring the levels of multiple proteins (Elastin, Collagen I, Collagen III, IL-6, TNF-α and MMP2) in the anterior vaginal walls of PFD rats. The application of exosomes derived from TNF-α-treated BMSCs holds promise as a novel therapeutic approach for treating PFD.

A phase I/II clinical trial of ex-vivo expanded human bone marrow derived allogeneic mesenchymal stromal cells in adult patients with perianal fistulizing Crohn's Disease

BACKGROUND

Perianal fistulas (PF) affect one-third patients with Crohn's disease (CD) with limited therapeutic options. There is dearth of literature on safety and efficacy of bone marrow-derived mesenchymal stromal cells (BMSCs) in this population.

METHODS

An open-label, phase I/II, single-arm study was conducted involving local administration of human allogeneic bone marrow-derived mesenchymal stromal cells in perianal fistula of patients with Crohn's disease refractory to standard therapies. Clinical severity and biomarkers were assessed at baseline and periodically until week 104 , and MRI at week 24 and 104. Primary and secondary objectives were to assess safety and efficacy respectively. Fistula remission was complete closure of fistula openings with < 2 cm perianal collection on MRI, and fistula response was decrease in drainage by ≥ 50%. Change in perianal disease activity index, quality-of-life and Van Assche index on MRI over time was assessed using mixed-effect linear regression model.

RESULTS

Ten patients (male:8, mean age:27.4 ± 12.0years) were recruited. Self-resolving procedure-related adverse events occurred in three patients, with no follow-up adverse events. In intention to treat analysis at week 24, two patients (20%) achieved fistula remission and seven (70%) had fistula response. At week 52, two (20%) patients were in remission and seven (70%) maintained response. At 104 weeks, two (20%) patients maintained response and one (10%) was in remission. Statistically significant decrease in perianal disease activity index (P = 0.008), Van Assche Index (P = 0.008) and improvement in quality-of-life (P = 0.001) were observed over time.

CONCLUSIONS

Allogeneic BMSCs are safe and effective for the treatment of perianal fistulizing CD with significant improvement in clinical severity and radiological healing.

TRIAL REGISTRATION

The study was prospectively registered on Clinical trials registry - India (CTRI), CTRI/2020/01/022743 on 14 January 2020, http://ctri.nic.in .

Role of umbilical cord mesenchymal stromal cells in skin rejuvenation

Aging is the main cause of many degenerative diseases. The skin is the largest and the most intuitive organ that reflects the aging of the body. Under the interaction of endogenous and exogenous factors, there are cumulative changes in the structure, function, and appearance of the skin, which are characterized by decreased synthesis of collagen and elastin, increased wrinkles, relaxation, pigmentation, and other aging characteristics. skin aging is inevitable, but it can be delayed. The successful isolation of mesenchymal stromal cells (MSC) in 1991 has greatly promoted the progress of cell therapy in human diseases. The International Society for Cellular Therapy (ISCT) points out that the MSC is a kind of pluripotent progenitor cells that have self-renewal ability (limited) in vitro and the potential for mesenchymal cell differentiation. This review mainly introduces the role of perinatal umbilical cord-derived MSC(UC-MSC) in the field of skin rejuvenation. An in-depth and systematic understanding of the mechanism of UC-MSCs against skin aging is of great significance for the early realization of the clinical transformation of UC-MSCs. This paper summarized the characteristics of skin aging and summarized the mechanism of UC-MSCs in skin rejuvenation reported in recent years. In order to provide a reference for further research of UC-MSCs to delay skin aging.

The Immunomodulatory effect of exosomes in diabetes: a novel and attractive therapeutic tool in diabetes therapy

Exosomes carry proteins, metabolites, nucleic acids and lipids from their parent cell of origin. They are derived from cells through exocytosis, are ingested by target cells, and can transfer biological signals between local or distant cells. Therefore, exosomes are often modified in reaction to pathological processes, including infection, cancer, cardiovascular diseases and in response to metabolic perturbations such as obesity and diabetes, all of which involve a significant inflammatory aspect. Here, we discuss how immune cell-derived exosomes origin from neutrophils, T lymphocytes, macrophages impact on the immune reprogramming of diabetes and the associated complications. Besides, exosomes derived from stem cells and their immunomodulatory properties and anti-inflammation effect in diabetes are also reviewed. Moreover, As an important addition to previous reviews, we describes promising directions involving engineered exosomes as well as current challenges of clinical applications in diabetic therapy. Further research on exosomes will explore their potential in translational medicine and provide new avenues for the development of effective clinical diagnostics and therapeutic strategies for immunoregulation of diabetes.

Efficient healing of diabetic wounds by MSC-EV-7A composite hydrogel via suppression of inflammation and enhancement of angiogenesis

Diabetes mellitus (DM) is characterized by prolonged hyperglycemia, impaired vascularization, and serious complications, such as blindness and chronic diabetic wounds. About 25% of patients with DM are estimated to encounter impaired healing of diabetic wounds, often leading to lower limb amputation. Multiple factors are attributed to the non-healing of diabetic wounds, including hyperglycaemia, chronic inflammation, and impaired angiogenesis. It is imperative to develop more efficient treatment strategies to tackle healing difficulties in diabetic wounds. Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are promising for diabetic wound healing considering their anti-inflammatory, pro-angiogenic and pro-proliferative activities. A histone deacetylase 7 (HDAC7)-derived 7-amino-acid peptide (7A) was shown to be highly effective for angiogenesis. However, it has never been investigated whether MSC-EVs are synergistic with 7A for the healing of diabetic wounds. Herein, we propose that MSC-EVs can be combined with 7A to greatly promote diabetic wound healing. The combination of EVs and 7A significantly improved the migration and proliferation of skin fibroblasts. Moreover, EVs alone significantly suppressed LPS-induced inflammation in macrophages, and notably, the combination treatment showed an even better suppression effect. Importantly, the in vivo study revealed that the combination therapy consisting of EVs and 7A in an alginate hydrogel was more efficient for the healing of diabetic wounds in rats than monotherapy using either EV or 7A hydrogels. The underlying mechanisms include suppression of inflammation, improvement of skin cell proliferation and migration, and enhanced collagen fiber disposition and angiogenesis in wounds. In summary, the MSC-EV-7A hydrogel potentially constitutes a novel therapy for efficient healing of chronic diabetic wounds.

A systematic review of the exercise effects on burn wound healing

The emerging evidence has indicated the role of microRNAs (miRNA) in various physiological or pathological processes. Also, documents have suggested that exercise, by affecting miRNA regulation, may enhance burn wound healing. The current study aims to systematically review the role of exercise in regulating miRNAs related to burn wound healing to provide potential therapeutic targets. A comprehensive, systematic search was performed in different international electronic databases, such as Embase, PubMed and Google Scholar search engine, Science Direct, ProQuest and Ovid using keywords extracted from Medical Subject Headings from 2010 to September 2023. The keywords, including 'exercise' AND 'burn wound' AND 'microRNA' and finally, six cases were achieved. Evidence has indicated that exercise may promote the healing of burn wounds by regulating certain miRNAs. Studies have found that exercise regulates the expression of miRNAs such as mir-155, miR-21, let-7a, miR-146a, miR-122 and mir-210 in burn wound tissue, which regulate inflammation and angiogenesis. These findings suggest that miRNAs may play a role in the positive effect of exercise on burn wound healing. However, further research is needed to understand the mechanisms involved fully.

Low‑intensity pulsed ultrasound accelerates diabetic wound healing by ADSC‑derived exosomes via promoting the uptake of exosomes and enhancing angiogenesis

Diabetic wounds remain a great challenge for clinicians globally as a lack of effective radical treatment often results in poor prognosis. Exosomes derived from adipose‑derived stem cells (ADSC‑Exos) have been explored as an appealing nanodrug delivery system in the treatment of diabetic wounds. However, the short half‑life and low utilization efficiency of exosomes limit their therapeutic effects. Low‑intensity pulsed ultrasound (LIPUS) provides a non‑invasive mechanical stimulus to cells and exerts a number of biological effects such as cavitation and thermal effects. In the present study, whether LIPUS could enhance ADSC‑Exo‑mediated diabetic wound repair was investigated and its possible mechanism of action was explored. After isolation and characterization, ADSC‑Exos were injected into mice with diabetic wounds, then the mice were exposed to LIPUS irradiation. The control mice were subcutaneously injected with PBS. Wound healing assays, laser Doppler perfusion, Masson's staining and angiogenesis assays were used to assess treatment efficiency. Then, ADSC‑Exos were cocultured with human umbilical vein endothelial cells (HUVECs), and the proliferation, migration and tube formation of HUVECs were assessed. Moreover, the cellular uptake of ADSC‑Exos in vitro and in vivo was assessed to explore the synergistic mechanisms underlying the effects of LIPUS. The in vivo results demonstrated that LIPUS increased the uptake of exosomes and prolonged the residence of exosomes in the wound area, thus enhancing angiogenesis and accelerating wound repair in diabetic mice. The in vitro results further confirmed that LIPUS enhanced the uptake efficiency of ADSC‑Exos by 10.93‑fold and significantly increased the proliferation, migration and tubular formation of HUVECs. Therefore, the present study indicates that LIPUS is a promising strategy to improve the therapeutic effects of ADSC‑Exos in diabetic wounds by promoting the cellular uptake of exosomes and enhancing angiogenesis.

Extracellular vesicles secreted by bone marrow stem cells mediate angiogenesis for the treatment of diabetic ulcers: A systematic review and meta-analysis of preclinical studies

Background

Diabetic ulcers (DUs) typically occur in patients with vascular diseases and diabetes. Extracellular vesicles secreted by bone marrow-derived stem cells (BMSC-EVs) represent a cell-free therapy that has emerged as a promising alternative for treating DU, especially due to significant advancements in the understanding of their role in promoting angiogenesis; however, their application in DU treatment remains in the preclinical stage, and their effectiveness is still uncertain. Therefore, we conducted this meta-analysis to evaluate the therapeutic efficacy of BMSC-EVs in treating DU and to expedite the clinical translation of BMSC-EV therapy for DU.

Methods

We conducted a comprehensive search of PubMed, Cochrane Library, MEDLINE, EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Database, and our self-constructed database of Chinese Biomedical Literature up to May 2023 to identify preclinical studies related to the therapeutic use of extracellular vesicles secreted by bone marrow-derived stem cells for treating diabetic ulcers. Outcome measures included wound healing rate, neovascularization density, a-sma, and CD31. RevMan 5 software was employed for all statistical analyses.

Results

In this meta-analysis, a total of 11 studies involving 103 animals were identified. The pooled analysis indicated that BMSC-EV treatment showed a superior wound healing rate compared to that of the control group (SMD = 1.06, 95% CI [0.52, 1.60], P = 0.0001). In the subgroup analysis, EV combined with new materials or drug therapy performed better than the sole injection of extracellular vesicles (SMD = 1.85, 95% CI [0.87, 2.82], P < 0.00001). BMSC-EV treatment also resulted in a higher number of neovascular structures compared to the control group(SMD = 5.80, 95% CI[0.89,10.71], P = 0.006). In the subgroup analysis, EV combined therapy showed a significant difference in the number of blood vessels compared to the sole injection of extracellular vesicles (SMD = 4.90, 95% CI[2.64,7.15], P < 0.00001). However, BMSCs-EV treatment did not demonstrate any statistically significant difference in the angiogenesis-related indicators CD31 and α-SMA compared to the control group (SMD = 1.61, 95% CI[-0.51,3.74], P = 0.14).

Conclusion

According to the current meta-analysis, BMSC-EV therapy can enhance the healing of diabetic ulcers and promote wound angiogenesis, particularly when used in combination with novel dressings or other drugs, which further accelerates the healing process of diabetic ulcers. To establish the most effective parameters for EV treatment in diabetic ulcers, future research should promptly progress into clinical trials.

Research progress on and molecular mechanism of vacuum sealing drainage in the treatment of diabetic foot ulcers

Diabetic foot ulcers (DFUs) are common chronic wounds and a common complication of diabetes. The foot is the main site of diabetic ulcers, which involve small and medium-sized arteries, peripheral nerves, and microcirculation, among others. DFUs are prone to coinfections and affect many diabetic patients. In recent years, interdisciplinary research combining medicine and material science has been increasing and has achieved significant clinical therapeutic effects, and the application of vacuum sealing drainage (VSD) in the treatment of DFUs is a typical representative of this progress, but the mechanism of action remains unclear. In this review, we integrated bioinformatics and literature and found that ferroptosis is an important signaling pathway through which VSD promotes the healing of DFUs and that System Xc-GSH-GPX4 and NAD(P)H-CoQ10-FSP1 are important axes in this signaling pathway, and we speculate that VSD is most likely to inhibit ferroptosis to promote DFU healing through the above axes. In addition, we found that some classical pathways, such as the TNF, NF-κB, and Wnt/β-catenin pathways, are also involved in the VSD-mediated promotion of DFU healing. We also compiled and reviewed the progress from clinical studies on VSD, and this information provides a reference for the study of VSD in the treatment of DFUs.

Age-different BMSCs-derived exosomes accelerate tendon-bone interface healing in rotator cuff tears model

BACKGROUND

Rotator cuff tears (RCTs) are culprit of shoulder pain and dysfunction. Tendon-bone interface (TBI) mal-healing is an essential contributor to retear after RCTs. Consequently, present project was conducted to investigate the role of bone marrow mesenchymal stem cells (BMSCs)-derived exosomes on TBI healing.

METHOD

Young BMSCs (Y-BMSCs) and Aged BMSCs (A-BMSCs) were isolated from Young (3-month-old) and old (24-month-old) SD rats, and their-derived exosomes (A-BMSCs-exo and Y-BMSCs-exo) were identified. RCTs model was established, and A-BMSCs-exo and Y-BMSCs-exo were injected at the rotator cuff using hydrogel as a vehicle. Pathological changes of TBI were observed by HE, Sirius Red and Oil Red O staining. Western blotting and RT-qPCR were applied to assess the expression of extracellular matrix (ECM)-, tendon cell (TCs)-, osteogenic-, tendon-derived stem cell (TDSCs)- and angiogenic-associated proteins and mRNAs in TBI.

RESULT

Y-BMSCs exhibited increased activity, osteogenic and lipogenic abilities than A-BMSCs. After A-BMSCs-exo and Y-BMSCs-exo treatment, TBI displayed massive sharpey's fibers growing along the tendon longitudinally, and a collagen fiber-chondrocyte migration zone forming a typical tendon-noncalcified fibrocartilage-calcified fibrocartilage-bone structure. A-BMSCs-exo and Y-BMSCs-exo significantly upregulated the expression of collagen Col I/II/III, Aggrecan, TNMD, SCX, Runx2, OPN, CD45, Sox2, CD31 and VEGFR2 in TBI. In vitro, A-BMSCs-exo and Y-BMSCs-exo significantly enhanced the activity of TCs and TDSCs, TDSCs stemness, and reduced the osteogenic and lipogenic capacity of TDSCs. The effect of Y-BMSCs-exo was significantly stronger than that of A-BMSCs-exo.

CONCLUSION

BMSCs-derived exosomes facilitate ECM remodeling, osteogenic differentiation, angiogenesis, and stemness of TDSCs, thereby accelerating TBI healing in RCTs, with better outcomes using young individual-derived BMSCs.

Edible Plant-Derived Extracellular Vesicles for Oral mRNA Vaccine Delivery

Nucleic acid delivery through extracellular vesicles (EVs) is a well-preserved evolutionary mechanism in all life kingdoms including eukaryotes, prokaryotes, and plants. EVs naturally allow horizontal transfer of native as well as exogenous functional mRNAs, which once incorporated in EVs are protected from enzymatic degradation. This observation has prompted researchers to investigate whether EVs from different sources, including plants, could be used for vaccine delivery. Several studies using human or bacterial EVs expressing mRNA or recombinant SARS-CoV-2 proteins showed induction of a humoral and cell mediated immune response. Moreover, EV-based vaccines presenting the natural configuration of viral antigens have demonstrated advantages in conferring long-lasting immunization and lower toxicity than synthetic nanoparticles. Edible plant-derived EVs were shown to be an alternative to human EVs for vaccine delivery, especially via oral administration. EVs obtained from orange juice (oEVs) loaded with SARS-CoV-2 mRNAs protected their cargo from enzymatic degradation, were stable at room temperature for one year, and were able to trigger a SARS-CoV-2 immune response in mice. Lyophilized oEVs containing the S1 mRNA administered to rats via gavage induced a specific humoral immune response with generation of blocking antibodies, including IgA and Th1 lymphocyte activation. In conclusion, mRNA-containing oEVs could be used for developing new oral vaccines due to optimal mucosal absorption, resistance to stress conditions, and ability to stimulate a humoral and cellular immune response.

Exosomes derived from BMSCs enhance diabetic wound healing through circ-Snhg11 delivery

BACKGROUND

Exosomes (Exos) generated from bone mesenchymal stem cells (BMSCs) are elucidated to enhance cutaneous wound healing in mice models of diabetes mellitus (DM). While underlying mechanisms remain unknown.

METHODS

Next-generation sequencing (NGS) was used to examine changes in circRNA expression levels following Exo treatment. Luciferase assays were used to determine the interactions between RNAs. Immunofluorescence staining was used to examine reactive oxygen species (ROS) in endothelial progenitor cells (EPCs) cultured in high glucose (HG) conditions. Therapeutic effects regarding Exos were also examined by immunofluorescence.

RESULTS

We found that Exo treatment enhanced cutaneous wound healing significantly. NGS indicated that circ-Snhg11 was involved in Exo-mediated tissue repairing. Downregulation of circ-Snhg11 decreased Exo-mediated therapy responses during wound healing in diabetic mouse. Our luciferase reporter data confirmed that SLC7A11 and miR-144-3p were circ-Snhg11 downstream targets. miR-144-3p overexpression or SLC7A11 knockdown altered the protective effects of circ-Snhg11 upon EPCs exposed to HG conditions. Upregulation of circ-Snhg11 incremented therapy effects of Exo treatment during wound healing in DM mice through enhanced angiogenesis along with a reduction in GPX4-mediated ferroptosis.

CONCLUSIONS

circ-Snhg11 in BMSC-Exos enhanced SLC7A11/GPX4-mediated anti-ferroptosis signals via miR-144-3p sponging resulting in enhanced diabetic wound healing and improved angiopoiesis.

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Functionalised biomaterials as synthetic extracellular matrices to promote vascularisation and healing of diabetic wounds

Diabetic foot ulcers (DFU) are a type of chronic wound that constitute one of the most serious and debilitating complications associated with diabetes. The lack of clinically efficacious treatments to treat these recalcitrant wounds can lead to amputations for those worst affected. Biomaterial-based approaches offer great hope in this regard, as they provide a template for cell infiltration and tissue repair. However, there is an additional need to treat the underlying pathophysiology of DFUs, in particular insufficient vascularization of the wound which significantly hampers healing. Thus, the addition of pro-angiogenic moieties to biomaterials is a promising strategy to promote the healing of DFUs and other chronic wounds. In this review, we discuss the potential of biomaterials as treatments for DFU and the approaches that can be taken to functionalise these biomaterials such that they promote vascularisation and wound healing in pre-clinical models.

Extracellular Vesicles in the Skin Microenvironment: Emerging Roles as Biomarkers and Therapeutic Tools in Dermatologic Health and Disease

The recent discovery of extracellular vesicles (EVs) carrying cargo consisting of various bioactive macromolecules that can modulate the phenotype of recipient target cells has revealed an important new mechanism through which cells can signal their neighbors and regulate their microenvironment. Because EV cargo and composition correlate with the physiologic state of their cell of origin, investigations into the role of EVs in disease pathogenesis and progression have become an area of intense study. The physiologic and pathologic effects of EVs on their microenvironment are incredibly diverse and include the modulation of molecular pathways involved in angiogenesis, inflammation, wound healing, epithelial-mesenchymal transition, proliferation, and immune escape. This review examines recent studies on the role of EVs in diseases of the skin and on how differences in EV composition and cargo can alter cell states and the surrounding microenvironment. We also discuss the potential clinical applications of EVs in skin disease diagnosis and management. We examine their value as an easily isolated source of biomarkers to predict disease prognosis or to monitor patient response to treatment. Given the ability of EVs to modulate disease-specific signaling pathways, we also assess their potential to serve as novel personalized precision therapeutic tools for dermatological diseases.

Exosome-based delivery strategies for tumor therapy: an update on modification, loading, and clinical application

Malignancy is a major public health problem and among the leading lethal diseases worldwide. Although the current tumor treatment methods have therapeutic effect to a certain extent, they still have some shortcomings such as poor water solubility, short half-life, local and systemic toxicity. Therefore, how to deliver therapeutic agent so as to realize safe and effective anti-tumor therapy become a problem urgently to be solved in this field. As a medium of information exchange and material transport between cells, exosomes are considered to be a promising drug delivery carrier due to their nano-size, good biocompatibility, natural targeting, and easy modification. In this review, we summarize recent advances in the isolation, identification, drug loading, and modification of exosomes as drug carriers for tumor therapy alongside their application in tumor therapy. Basic knowledge of exosomes, such as their biogenesis, sources, and characterization methods, is also introduced herein. In addition, challenges related to the use of exosomes as drug delivery vehicles are discussed, along with future trends. This review provides a scientific basis for the application of exosome delivery systems in oncological therapy.

Exosomes from adipose-derived stem cells restore fibroblast function and accelerate diabetic wound healing

Background

Diabetes is common yet challenging chronic disease, that affects a wide range of people around the world. Complex cellular environments around diabetic wounds tend to damage the function of effector cells, including vascular endothelial cells (VECs), fibroblasts and epithelial cells. This study aims to analyze the differences between diabetic wounds and normal skin as well as whether adipose-derived stem cell (ADSC) exosome could promote healing of diabetic wound.

Methods

Human diabetic wounds and normal skin were collected and stained with HE, Masson, CD31 and 8-hydroxy-2 deoxyguanosine immunohistochemical staining. RNA-seq data were collected for further bioinformatics analysis. ADSC exosomes were isolated and identified by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting. The effect of ADSC exosomes on diabetic wound healing was assessed on full thickness wounds in mice. To further verify the regulative impact of ADSCs exosomes in high glucose treated fibroblasts, we isolated fibroblasts from normal skin tissue and measured the cell viability, apoptosis rate, proliferation and migration of fibroblasts. In addition, collagen formation and fibrosis-related molecules were also detected. To further disclose the mechanism of ADSC exosomes on the function of high glucose treated fibroblasts, we detected the expression of apoptosis related molecules including BCL2, Bax, and cleaved caspase-3.

Results

Histological observation indicated that perilesional skin tissues from diabetic patients showed structural disorder, less collagen disposition and increased injury compared with normal skin. Bioinformatics analysis showed that the levels of inflammatory and collagen synthesis related molecules, as well as oxidative stress and apoptosis related molecules, were significantly changed. Furthermore, we found that ADSC exosomes could not only speed up diabetic wound healing, but could also improve healing quality. ADSC exosomes restored high glucose induced damage to cell viability, migration and proliferation activity, as well as fibrosis-related molecules such as SMA, collagen 1 and collagen 3. In addition, we verified that ADSC exosomes downregulated high glucose induced increased apoptosis rate in fibroblast and the protein expression of Bax as well as cleaved caspases 3.

Conclusions

This study indicated that ADSC exosomes alleviated high glucose induced damage to fibroblasts and accelerate diabetic wound healing by inhibiting Bax/caspase 3.

Effects of adipose-derived mesenchymal stem cell conditioned medium on human tenocytes exposed to high glucose

Introduction

Diabetic tendinopathy is a common invalidating and challenging disease that may be treated using stem cells. However, the effects of adipose-derived mesenchymal stem cell conditioned medium (ASC-CM) in diabetic tendinopathy have never been explored.

Objectives

The present study evaluated the effects of ASC-CM on morphology, cell viability, structure, and scratch wound closure of human tenocytes (HTNC) exposed to high glucose (HG).

Design

Experimental study.

Methods

HTNC were exposed to HG (25 mM) for 7, 14 and 21 days with or without ASC-CM for the last 24 h. CM was collected from 4 × 105 ASCs, centrifuged for 10 min at 200 g and sterilized with 0.22 μm syringe filter.

Results

At 7 days, HG-HTNC had decreased cell viability [72 ± 2%, p < 0.01 versus normal glucose (NG)] compared to NG-HTNC (90 ± 5%). A further decrement was detected after 14 and 21 days (60 ± 4% and 60 ± 5%, both, p < 0.01 versus NG and p < 0.01 versus HG7). While NG-HTNC evidenced a normal fibroblast cell-like elongated morphology, HG-HTNC showed increased cell roundness. In contrast, HG-HTNC exposed to ASC-CM showed a significant increase in cell viability, an improved cell morphology and higher scratch wound closure at all HG time points. Moreover, the exposure to ASC-CM significantly increased thrombospondin 1 and transforming growth factor beta 1 (TGF-β1) content in HG-HTNC. The TGF-β1 elevation was paralleled by higher Collagen I and Vascular Endothelial Growth Factor in HG-HTNC.

Conclusion

ASC-CM may restore the natural morphology, cell viability and structure of HTNC, promoting their scratch wound closure through TGF-β1 increase.

Translational studies of exosomes in sports medicine - a mini-review

This review in sports medicine focuses on the critical role of exosomes in managing chronic conditions and enhancing athletic performance. Exosomes, small vesicles produced by various cells, are essential for cellular communication and transporting molecules like proteins and nucleic acids. Originating from the endoplasmic reticulum, they play a vital role in modulating inflammation and tissue repair. Their significance in sports medicine is increasingly recognized, particularly in healing athletic injuries, improving articular cartilage lesions, and osteoarthritic conditions by modulating cellular behavior and aiding tissue regeneration. Investigations also highlight their potential in boosting athletic performance, especially through myocytes-derived exosomes that may enhance adaptability to physical training. Emphasizing a multidisciplinary approach, this review underlines the need to thoroughly understand exosome biology, including their pathways and classifications, to fully exploit their therapeutic potential. It outlines future directions in sports medicine, focusing on personalized treatments, clinical evaluations, and embracing technological advancements. This research represents a frontier in using exosomes to improve athletes' health and performance capabilities.

HMOX1-overexpressing mesenchymal stem cell-derived exosomes facilitate diabetic wound healing by promoting angiogenesis and fibroblast function

Many scholars have suggested that exosomes (Exos) can carry active molecules to induce angiogenesis and thus accelerate diabetic wound healing. Heme oxygenase-1 (HO-1) encoded by the gene HMOX1 promotes wound healing in DM by enhancing angiogenesis. Nevertheless, whether HMOX1 regulates wound healing in DM through mesenchymal stem cell-derived exosomes (MSC-Exos) remains to be further explored. The primary isolated- and cultured-cells expressed MSC-specific marker proteins, and had low immunogenicity and multi-differentiation potential, which means that MSCs were successfully isolated in this study. Notably, HO-1 protein expression was significantly higher in Exo-HMOX1 than in Exos, indicating that HMOX1 could be delivered to Exos as an MSCs-secreted protein. After verifying the -Exo structure, fibroblasts, keratinocytes, and human umbilical vein endothelial cells (HUVECs) were incubated with Exo-HMOX1 or Exo, and the findings displayed that Exo-HMOX1 introduction promoted the proliferation and migration of fibroblasts, keratinocytes and the angiogenic ability of HUVECs in vitro study. After establishing diabetic wound model mice, PBS, Exo, and Exo-HMOX1 were subcutaneously injected into multiple sites on the 1st, 3rd, 7th, and 14th day, DM injected with Exo-HMOX1 showed faster wound healing, re-epithelialization, collagen deposition, and angiogenesis than those in PBS and Exo groups in vitro study. In summary, Exo-HMOX1 could enhance the activity of fibroblasts, keratinocytes, and HUVEC, and accelerate wound healing by promoting angiogenesis in DM.

Development and characterization of islet-derived mesenchymal stem cells from clinical grade neonatal porcine cryopreserved islets

BACKGROUND

Porcine tissues display a great potential as donor tissues in xenotransplantation, including cell therapy. Cryopreserving clinical grade porcine tissue and using it as a source for establishing therapeutic cells should be advantageous for transportation and scheduled manufacturing of MSCs. Of note, we previously performed encapsulated porcine islet transplantation for the treatment of unstable type 1 diabetes mellitus in the clinical setting. It has been reported that co-transplantation of islets and Mesenchymal stem cells (MSCs) enhanced efficacy. We assume that co-transplantation of porcine islets and porcine islet-derived MSCs could improve the efficacy of clinical islet xenotransplantation.

METHODS

MSCs were established from fresh and cryopreserved non-clinical grade neonatal porcine islets and bone marrow (termed non-clinical grade npISLET-MSCs and npBM-MSCs, respectively), as well as from cryopreserved clinical grade neonatal porcine islets (termed clinical grade npISLET-MSCs). Subsequently, the cell proliferation rate and diameter, surface marker expression, adipogenesis, osteogenesis, and colony-forming efficiency of the MSCs were assessed.

RESULTS

Cell proliferation rate and diameter did not differ between clinical grade and non-clinical grade npISLET-MSCs. However, non-clinical grade npBM-MSCs were significantly shorter and smaller than both npISLET-MSCs (p < 0.05). MSC markers (CD29, CD44, and CD90) were strongly expressed in clinical grade npISLET-MSCs and non-clinical grade npISLET-MSCs and npBM-MSCs. The expression of MSC-negative markers CD31, CD34, and SLA-DR was low in all MSCs. Clinical grade npISLET-MSCs derived from adipose and osteoid tissues were positive for Oil Red and alkaline phosphatase staining. The results of colony-forming assay were not significantly different between clinical grade npISLET-MSCs and non-clinical grade npBM-MSCs.

CONCLUSION

The method described herein was successful in of developing clinical grade npISLET-MSCs from cryopreserved islets. Cryopreserved clinical grade porcine islets could be an excellent stable source of MSCs for cell therapy.

Mesenchymal stem cell-derived extracellular vesicles as a cell-free therapy for traumatic brain injury via neuroprotection and neurorestoration

Traumatic brain injury is a serious and complex neurological condition that affects millions of people worldwide. Despite significant advancements in the field of medicine, effective treatments for traumatic brain injury remain limited. Recently, extracellular vesicles released from mesenchymal stem/stromal cells have emerged as a promising novel therapy for traumatic brain injury. Extracellular vesicles are small membrane-bound vesicles that are naturally released by cells, including those in the brain, and can be engineered to contain therapeutic cargo, such as anti-inflammatory molecules, growth factors, and microRNAs. When administered intravenously, extracellular vesicles can cross the blood-brain barrier and deliver their cargos to the site of injury, where they can be taken up by recipient cells and modulate the inflammatory response, promote neuroregeneration, and improve functional outcomes. In preclinical studies, extracellular vesicle-based therapies have shown promising results in promoting recovery after traumatic brain injury, including reducing neuronal damage, improving cognitive function, and enhancing motor recovery. While further research is needed to establish the safety and efficacy of extracellular vesicle-based therapies in humans, extracellular vesicles represent a promising novel approach for the treatment of traumatic brain injury. In this review, we summarize mesenchymal stem/stromal cell-derived extracellular vesicles as a cell-free therapy for traumatic brain injury via neuroprotection and neurorestoration and brain-derived extracellular vesicles as potential biofluid biomarkers in small and large animal models of traumatic brain injury.

Diabetic and nondiabetic BMSC-derived exosomes affect bone regeneration via regulating miR-17-5p/SMAD7 axis

Diabetic bone disease (DBD) is a complication of diabetes mellitus (DM) and is characterized by impaired osteocyte function and delayed bone remodeling due to high blood glucose levels and sustained release of inflammatory factors. Recent studies show that the regulation of osteoblasts (OBs) by bone marrow stromal cells (BMSCs) is an important mechanism in alleviating DBD and that exosomes are recognized as the key medium. Mesenchymal stem cell-derived exosome (MSC-Exos) therapy is a promising approach to facilitate tissue repair. However, the influence of exosomes from diabetic conditioned BMSCs on OBs and bone regeneration, as well as the underlying mechanism, are still elusive. Here, we used high-glucose medium to mimic diabetic conditions and normal-glucose medium as control to mimic nondiabetic conditions in vitro and found that microRNA-17 (miR-17) was downregulated in diabetic-conditioned BMSC-derived exosomes (HG-Exos), HG-Exo-co-cultured osteoblasts, and the skull of rats with type 2 diabetes mellitus (T2DM). Further experiment concluded that nondiabetic conditioned BMSC-Exos (NG-Exos) promoted the osteogenesis of OBs and bone regeneration of rats with T2DM via upregulation of miR-17. Compare with NG-Exos, HG-Exos impeded osteogenesis of OBs in vitro and bone regeneration of rats in vivo by downregulation of miR-17. Moreover, miR-17 promoted bone regeneration by targeting SMAD7, which was further proved to have a negative effect on osteogenesis. Taken together, nondiabetic BMSC-derived exosomes greatly foster bone regeneration, whereas diabetic BMSC-derived exosomes undermine the promotion effect of MSC-Exos by regulating the miR-17/SMAD7 axis. These findings provide support for the miR-17-5p/SMAD7 axis as a promising therapeutic target to treat DBD.

Investigation on repairing diabetic foot ulcer based on 3D bio-printing Gel/dECM/Qcs composite scaffolds

Diabetic foot ulcers are one of the most serious of the numerous complications of diabetes mellitus, causing great physical trauma and financial stress to patients, and accelerating wound healing in diabetic patients remains one of the major clinical challenges. Exosomes from adipose-derived stem cells can directly and indirectly promote wound healing. However, due to the low retention rate of exosomes in the wound, exosome treatment is difficult to achieve the expected effect. Therefore, it is of great significance to synthesize a composite scaffold that can stably load exosomes and has antibacterial properties. In this study, fresh pig skin was decellularized to obtain decellularized matrix (dECM). Secondly, quaternized chitosan (Qcs) was modified with quaternary ammonium salt to make it soluble in water after quaternization. Finally, Gel-dECM-Qcs (GDQ) bioink was prepared by adding acellular matrix and quaternized chitosan with temperature sensitive gelatin (Gel) as carrier. Tissue engineered composite scaffolds were then prepared by extrusion 3D printing technology. Subsequently, the physicochemical properties, biocompatibility and antimicrobial capacity of the composite scaffolds were determined, and the data showed that the composite scaffolds had good mechanical properties, biocompatibility and antimicrobial capacity, and the maximum stress of the composite scaffolds was 1.16 ± 0.05 MPa, the composite scaffolds were able to proliferate and adhered to the L929 cells, and the kill rates of composite scaffolds against E. coli and S. aureus after incubation for 24 h were 93.24 ± 1.22 % and 97.34 ± 0.23 %, respectively. Overall, the GDQ composite scaffolds have good mechanical properties adapted to skin bending, its good biocompatibility can promote the growth and migration of fibroblasts, reshape injured tissues, accelerate the wound healing, and excellent antimicrobial ability can inhibit the growth of E. coli and S. aureus, reducing the impact of bacterial infections on wounds. Moreover, the composite scaffolds have the potential to be used as exosom-loaded hydrogel dressings, which provides a basis for the subsequent research on the repair of diabetic foot ulcers.

Bone marrow mesenchymal stem cell‑derived exosomes: A novel therapeutic agent for tendon‑bone healing (Review)

In sports medicine, injuries related to the insertion of tendons into bones, including rotator cuff injuries, anterior cruciate ligament injuries and Achilles tendon ruptures, are commonly observed. However, traditional therapies have proven to be insufficient in achieving satisfactory outcomes due to the intricate anatomical structure associated with these injuries. Adult bone marrow mesenchymal stem cells possess self‑renewal and multi‑directional differentiation potential and can generate various mesenchymal tissues to aid in the recovery of bone, cartilage, adipose tissue and bone marrow hematopoietic tissue. In addition, extracellular vesicles derived from bone marrow mesenchymal stem cells known as exosomes, contain lipids, proteins and nucleic acids that govern the tissue microenvironment, facilitate tissue repair and perform various biological functions. Studies have demonstrated that bone marrow mesenchymal stem cell‑derived exosomes can function as natural nanocapsules for drug delivery and can enhance tendon‑bone healing strength. The present review discusses the latest research results on the role of exosomes released by bone marrow mesenchymal stem cells in tendon‑bone healing and provides valuable information for implementing these techniques in regenerative medicine and sports health.

White adipose tissue-derived small extracellular vesicles: A new potential therapeutic reagent for accelerating diabetic wound healing

Small extracellular vesicles (sEVs) from adipose-derived stem cells (ADSCs) have gained great attention and have been widely used in cell-free therapies for treating diabetic non-healing wounds in recent years. However, further clinical application of ADSC-sEVs have been limited due to their unsolvable defects, including cumbersome extraction procedure, high cost, low yield, etc. Thus, we urgently need to find one therapeutic reagent that could not only accelerate diabetic wound healing as ADSC-sEVs but also overcome these shortcomings. As the extraction process of adipose tissue-derived sEVs (AT-sEVs) is quite simple and labor saving, we put our focus on the efficiencies of white adipose tissue-derived sEVs (WAT-sEVs) and brown adipose tissue-derived sEVs (BAT-sEVs) in diabetic wound repair. After successfully isolating WAT-sEVs and BAT-sEVs by ultracentrifugation, we thoroughly characterized them and compared their diabetic wound healing capabilities both in vitro and in vivo. According to our study, AT-sEVs possess similar competence in diabetic wound healing as compared with ADSC-sEVs. While the effect of BAT-sEVs is not as stable as WAT-sEVs and ADSC-sEVs, the repair efficiency is also slightly lower than the other two sEVs in some cases. In summary, we are the first to discover that WAT-sEVs show great potential in diabetic wound repair. With advantages that are specific to tissue-derived sEVs (Ti-sEVs) such as time- and cost-saving, high-yield, and simple isolation procedure, we believe WAT-sEVs could serve as a novel reliable cell-free therapy for clinical diabetic wound treatment.

Extracellular vesicles modulate key signalling pathways in refractory wound healing

Chronic wounds are wounds that cannot heal properly due to various factors, such as underlying diseases, infection or reinjury, and improper healing of skin wounds and ulcers can cause a serious economic burden. Numerous studies have shown that extracellular vesicles (EVs) derived from stem/progenitor cells promote wound healing, reduce scar formation and have significant advantages over traditional treatment methods. EVs are membranous particles that carry various bioactive molecules from their cellular origins, such as cytokines, nucleic acids, enzymes, lipids and proteins. EVs can mediate cell-to-cell communication and modulate various physiological processes, such as cell differentiation, angiogenesis, immune response and tissue remodelling. In this review, we summarize the recent advances in EV-based wound healing, focusing on the signalling pathways that are regulated by EVs and their cargos. We discuss how EVs derived from different types of stem/progenitor cells can promote wound healing and reduce scar formation by modulating the Wnt/β-catenin, phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin, vascular endothelial growth factor, transforming growth factor β and JAK-STAT pathways. Moreover, we also highlight the challenges and opportunities for engineering or modifying EVs to enhance their efficacy and specificity for wound healing.

Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer: A review

The complication of diabetes, which is known as diabetic foot ulcer (DFU), is a significant concern due to its association with high rates of disability and mortality. It not only severely affects patients’ quality of life, but also imposes a substantial burden on the healthcare system. In spite of efforts made in clinical practice, treating DFU remains a challenging task. While mesenchymal stem cell (MSC) therapy has been extensively studied in treating DFU, the current efficacy of DFU healing using this method is still inadequate. However, in recent years, several MSCs-based drug delivery systems have emerged, which have shown to increase the efficacy of MSC therapy, especially in treating DFU. This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

Advancements in engineered exosomes for wound repair: current research and future perspectives

Wound healing is a complex and prolonged process that remains a significant challenge in clinical practice. Exosomes, a type of nanoscale extracellular vesicles naturally secreted by cells, are endowed with numerous advantageous attributes, including superior biocompatibility, minimal toxicity, and non-specific immunogenicity. These properties render them an exceptionally promising candidate for bioengineering applications. Recent advances have illustrated the potential of exosome therapy in promoting tissue repair. To further augment their therapeutic efficacy, the concept of engineered exosomes has been proposed. These are designed and functionally modifiable exosomes that have been tailored on the attributes of natural exosomes. This comprehensive review delineates various strategies for exosome engineering, placing specific emphasis on studies exploring the application of engineered exosomes for precision therapy in wound healing. Furthermore, this review sheds light on strategies for integrating exosomes with biomaterials to enhance delivery effectiveness. The insights presented herein provide novel perspectives and lay a robust foundation for forthcoming research in the realm of cutaneous wound repair therapies.

Cell Therapy and Investigation of the Angiogenesis of Fibroblasts with Collagen Hydrogel on the Healing of Diabetic Wounds

Objectives

A diabetic ulcer is a common disease in patients with diabetes. Because of antibiotic resistance, new therapeutic alternatives are being considered in diabetic foot patients to reduce complications and mortality. This study aimed to evaluate the effect of collagen hydrogel on the wound-healing process in diabetic rats.

Materials and Methods

Diabetic wounds were induced with streptozotocin in all 42 male Wistar rats. The rats were divided into four groups: (a) treated with fibroblast cells, (b) collagen hydrogel, (c) collagen cultured with fibroblast cells, and (d) a control group. Microscopic and histological (hematoxylin and eosin staining and Mason trichrome staining), measurement of wound surface with image J, skin density and thickness by the ultrasound probe, and skin elasticity with cytometer tool were used to evaluate wound healing at days 14 and 21 after the treatment.

Results

The results showed that treating diabetic wounds with fibroblasts cultured in collagen hydrogel greatly reduces inflammatory responses in the skin tissue and significantly accelerates the healing process. In addition, 21 days after the start of treatment, skin elasticity, thickness, and density were higher in the collagen + fibroblast group than in the control group.

Conclusion

In addition, the results of the present study show that diabetic wound dressing can significantly reduce the inflammatory phase in the wound healing process by increasing the speed of collagen synthesis, skin density and elasticity, and angiogenesis.

Advances in the Applications of Extracellular Vesicle for the Treatment of Skin Photoaging: A Comprehensive Review

Skin photoaging is a complex biological process characterized by the accumulation of oxidative damage and structural changes in the skin, resulting from chronic exposure to ultraviolet (UV) radiation. Despite the growing demand for effective treatments, current therapeutic options for skin photoaging remain limited. However, emerging research has highlighted the potential of extracellular vesicles (EVs), including exosomes, micro-vesicles, apoptotic bodies and liposomes, as promising therapeutic agents in skin rejuvenation. EVs are involved in intercellular communication and can deliver bioactive molecules, including proteins, nucleic acids, and lipids, to recipient cells, thereby influencing various cellular processes. This comprehensive review aims to summarize the current research progress in the application of EVs for the treatment of skin photoaging, including their isolation and characterization methods, roles in skin homeostasis, therapeutic potential and clinical applications for skin photoaging. Additionally, challenges and future directions in EVs-based therapies for skin rejuvenation are discussed.

Therapeutic potential of adipose tissue derivatives in skin photoaging

Photoaging, the primary cause of exogenous skin aging and predominantly caused by ultraviolet radiation, is an essential type of skin aging characterized by chronic skin inflammation. Recent studies have shown that oxidative stress, inflammation, skin barrier homeostasis, collagen denaturation and pigmentation are the main contributors to it. As a composite tissue rich in matrix and vascular components, adipose tissue derivatives have been recently gaining attention as potential therapeutic agents for various human diseases with fat-processing technology upgrades. This review analyzes both 'minimally treated' and 'nonminimally treated' fat derivatives to give an overview of the preclinical and clinical relevance of adipose tissue derivatives for antiphotoaging application, highlighting their good clinical prospects as well as discussing their safety and potential risks.

Extracellular Vesicles: Emergent and Multiple Sources in Wound Healing Treatment

Non-healing wound- and tissue-injury are commonly experienced worldwide by the aging population. The persistence of disease commonly leads to tissue infection, resulting in severe clinical complications. In the last decade, extracellular vesicles (EVs) have been considered promising and emergent therapeutic tools to improve the healing processes. Therefore, efforts have been directed to develop a cell-free therapeutic platform based on EV administration to orchestrate tissue repair. EVs derived from different cell types, including fibroblast, epithelial, and immune cells are recruited to the injured sites and in turn take part in scar formation. EVs are nano-sized particles containing a heterogeneous cargo consisting of lipids, proteins, and nucleic acids protected from degradation by their lipid bilayer. Noteworthy, since EVs have natural biocompatibility and low immunogenicity, they represent the ideal therapeutic candidates for regenerative purposes. Indeed, EVs are released by several cell types, and even if they possess unique biological properties, their functional capability can be further improved by engineering their content and functionalizing their surface, allowing a specific cell cargo delivery. Herein, we provide an overview of preclinical data supporting the contribution of EVs in the repair and regenerative processes, focusing on different naïve EV sources, as well as on their engineering, to offer a scalable and low-cost therapeutic option for tissue repair.