Role of mesenchymal stem cell derived extracellular vesicles in autoimmunity: A systematic review

MSC-derived extracellular vesicles: Precision miRNA delivery for overcoming cancer therapy resistance

Cancer remains a prominent worldwide health concern, presenting existing therapies with frequent difficulties, including major toxicity, limited effectiveness, and treatment resistance emergence. These issues highlight the necessity for novel and enhanced remedies. Exosomes, tiny extracellular vesicles that facilitate intercellular communication, have attracted interest for their potential medicinal applications. Carrying a variety of molecules, including microRNAs, small interfering RNAs, long non-coding RNAs, proteins, lipids, and DNA, these vesicles are positioned as promising cancer treatment options. Current studies have increasingly investigated the capacity of microRNAs as a strategic approach for combating malignancy. Mesenchymal stem cells (MSC) are recognized for their aptitude to augment blood vessel formation, safeguard against cellular death, and modulate immune responses. Consequently, researchers examine exosomes derived from MSCs as a safer, non-cellular choice over therapies employing MSCs, which risk undesirable differentiation. The focus is shifting towards employing miRNA-encapsulated exosomes sourced from MSCs to target and heal cancerous cells selectively. However, the exact functions of miRNAs within MSC-derived exosomes in the context of cancer are still not fully understood. Additional exploration is necessary to clarify the role of these miRNAs in malignancy progression and to pinpoint viable therapeutic targets. This review offers a comprehensive examination of exosomes derived from mesenchymal stem cells, focusing on the encapsulation of miRNAs, methods for enhancing cellular uptake and stability, and their potential applications in cancer treatment. It also addresses the difficulties linked to this methodology and considers future avenues, including insights from current clinical oncology research.

Immune-regulating extracellular vesicles: a new frontier in autoimmune disease therapy

Immune regulation is recognized as a cornerstone therapeutic strategy for the treatment of various autoimmune diseases. These disorders, driven by dysregulated immune responses, contribute significantly to morbidity and mortality. Although conventional immunosuppressive therapies provide symptomatic relief, their prolonged use is often associated with severe adverse effects, underscoring the need for safer and more effective treatment approaches. Extracellular vesicles (EVs), derived from immunoregulatory cells such as regulatory T cells, dendritic cells, mesenchymal stem cells, and neutrophils, have emerged as promising candidates for targeted immunomodulation. These nanoscale vesicles inherit the immunosuppressive properties of their parental cells, thereby facilitating immune homeostasis while mitigating the risks associated with other cell-based therapies. This review provides a comprehensive overview of recent advances in the application of immunoregulatory cell-derived EVs for autoimmune disease treatment, with a particular focus on their mechanisms of action within the immune microenvironment. Finally, we discuss the challenges and potential future directions in the development of EV-based therapies for autoimmune diseases.

Peptidomic profiling of mesenchymal stem cell-derived extracellular vesicles and anti-inflammatory activity of degraded peptides

Mesenchymal stem cell derived extracellular vesicles (MSC-EVs) are key paracrine mediators involved in various autoimmune diseases. While current research on EVs predominantly focuses on their protein and nucleic acid components, small peptides received less attention. In this study, we found IFN-γ-treated MSC-EVs, as engineered EVs, exhibit better anti-inflammatory effects both in vitro and in vivo. Through LC-MS/MS and bioinformatics analysis, we identified four peptides-C3-1, C3-2, B2M-1, and IFIT3-1-that are highly expressed in IFN-γ-treated MSCs-EVs. These peptides significantly mitigate the proliferation inhibition of HUVEC cells induced by H₂O₂ and enhance their migratory capacity. Furthermore, they downregulate the expression of inflammatory cytokines TNF-α and IL-6 in H₂O₂-induced oxidative stress models of HUVEC and LPS-induced inflammatory models of RAW264.7 macrophages. The peptides also upregulate p-AKT and HIF-1α, with C3-1 demonstrating superior anti-inflammatory efficacy in both cell models. Consistent with the in vitro findings, in vivo experiments revealed that C3-1 reduces LPS-induced inflammatory cell infiltration in liver tissue and restores hepatocyte structural integrity, as evidenced by HE-stained liver sections. Western blot analysis further confirmed that C3-1 upregulates p-AKT expression and suppresses inflammatory cytokines. Collectively, these findings suggest that C3-1 exerts its anti-inflammatory effects via activation of the AKT signaling pathway and regulation of TNF-α and IL-6. This study not only highlights the anti-inflammatory potential of IFN-γ-treated MSC-derived EVs but also identifies C3-1 as a promising candidate for anti-inflammatory drug development. Notably, this is the first study to identify degraded peptides within EVs, providing a foundation for future research in this area.

Exploring the potential mechanism of action of Wutou-Guizhi decoction in the treatment of rheumatoid arthritis through network pharmacology analysis

As a widely recognized traditional Chinese medicine (TCM) decoction prescription in China, numerous studies have shown that Wutou-Guizhi decoction (WTGZD) exhibits significant therapeutic efficacy for Rheumatoid arthritis (RA). Nevertheless, the underlying molecular mechanisms have yet to be fully elucidated. This study aims to establish a database of active ingredients for WTGZD and identify RA-related target genes. The WTGZD-RA-Potential target gene network and protein-protein interaction network were constructed, followed by gene ontology (GO) analysis and functional enrichment analysis utilizing the Kyoto Encyclopedia of Genes and Genomes (KEGG). Cell proliferation was confirmed through CCK8 assay. Target gene identification was performed via real-time PCR using quantitative methods, and western blot analysis was conducted. In the course of this investigation, 95 active components of drugs and 34 targets associated with rheumatoid arthritis were identified. Through the utilization of network pharmacology analysis, we were able to identify a total of 17 essential active components of WTGZD and pinpoint 12 significant targets linked to rheumatoid arthritis (RA). Our findings suggest a consistent interaction between the key components of WTGZD and the critical targets associated with RA. Subsequent qPCR analysis revealed that stigmasterol, a principal constituent of WTGZD, exhibited inhibitory effects on the expression of various RA-related factors, such as TNF-α, IL-1β, MAPK8, MMP1, MMP3, and MMP9. Moreover, WTGZD effectively mitigated the increased protein expression of MMP-1 and MAPK8 induced by LPS stimulation, both of which are integral components of the IL-17 signaling pathway. These results suggest that WTGZD may play a significant role in the therapeutic intervention of rheumatoid arthritis by suppressing inflammatory immune responses.

Mesenchymal stem cell secretome for regenerative medicine: Where do we stand?

BACKGROUND

Mesenchymal stem cell (MSC)-based therapies have yielded beneficial effects in a broad range of preclinical models and clinical trials for human diseases. In the context of MSC transplantation, it is widely recognized that the main mechanism for the regenerative potential of MSCs is not their differentiation, with in vivo data revealing transient and low engraftment rates. Instead, MSCs therapeutic effects are mainly attributed to its secretome, i.e., paracrine factors secreted by these cells, further offering a more attractive and innovative approach due to the effectiveness and safety of a cell-free product.

AIM OF REVIEW

In this review, we will discuss the potential benefits of MSC-derived secretome in regenerative medicine with particular focus on respiratory, hepatic, and neurological diseases. Both free and vesicular factors of MSC secretome will be detailed. We will also address novel potential strategies capable of improving their healing potential, namely by delivering important regenerative molecules according to specific diseases and tissue needs, as well as non-clinical and clinical studies that allow us to dissect their mechanisms of action.

KEY SCIENTIFIC CONCEPTS OF REVIEW

MSC-derived secretome includes both soluble and non-soluble factors, organized in extracellular vesicles (EVs). Importantly, besides depending on the cell origin, the characteristics and therapeutic potential of MSC secretome is deeply influenced by external stimuli, highlighting the possibility of optimizing their characteristics through preconditioning approaches. Nevertheless, the clarity around their mechanisms of action remains ambiguous, whereas the need for standardized procedures for the successful translation of those products to the clinics urges.

Exosome-based miRNA delivery: Transforming cancer treatment with mesenchymal stem cells

Recently, increasing interest has been in utilizing mesenchymal stem cell-derived extracellular vesicles (MSC-EVs), especially exosomes, as nanocarriers for miRNA delivery in cancer treatment. Due to such characteristics, nanocarriers are specific: biocompatible, low immunogenicity, and capable of spontaneous tumor accumulation. MSC-EVs were loaded with therapeutic miRNAs and minimized their susceptibility to degradation by protecting the miRNA from accessibility to degrading enzymes and providing targeted delivery of the miRNAs to the tumor cells to modulate oncogenic pathways. In vitro and in vivo experiments suggest that MSC-EVs loaded with miRNAs may inhibit tumor growth, prevent metastasis, and increase the effectiveness of chemotherapy and radiotherapy. However, these improvements present difficulties such as isolation, scalability, and stability of delivered miRNA during storage. Furthermore, the issues related to off-target effects, as well as immunogenicity, can be a focus. The mechanisms of miRNA loading into MSC-EVs, as well as their targeting efficiency and therapeutic potential, can be outlined in this manuscript. For the final part of the manuscript, the current advances in MSC-EV engineering and potential strategies for clinical application have been described. The findings of MSC-EVs imply that they present MSC-EVs as a second-generation tool for precise oncology.

Localized Administration of Mesenchymal Stem Cell-Derived Exosomes for the Treatment of Refractory Perianal Fistula in Patients With Crohn's Disease: A Phase II Clinical Trial

BACKGROUND

Crohn's disease perianal fistulas are often resistant to standard anti-tumor necrosis factor-α therapies. Mesenchymal stem cell-derived exosomes are extracellular vesicles with highly potent anti-inflammatory effects, and the previous phase of this study demonstrated their safety in the treatment of refractory perianal fistulas.

OBJECTIVE

To evaluate the efficacy of mesenchymal stem cell-derived exosomes for the treatment of refractory perianal fistulas.

DESIGN

Nonrandomized, nonblinded single-center phase II clinical trial.

SETTINGS

Tertiary university hospital.

PATIENTS

Twenty-three patients were enrolled, 20 of whom completed the study. Refractory perianal fistula was defined as resistance to at least 1 course of treatment with anti-tumor necrosis factor-α therapy.

INTERVENTIONS

After clinical assessment and MRI, the patients received general anesthesia, and 5 mL of exosome solution was injected directly into the fistula tracts. The injections were repeated 3 times at 2-month intervals, and patients were followed monthly for 6 months after the last injection. Tissue samples from the tracts were obtained before each injection and subjected to immunohistopathological assessment. MRI data were obtained before and 6 months after the last injection.

MAIN OUTCOME MEASURES

The primary outcome of this study was fistula tract closure on clinical examination and MRI. The secondary outcome was an improvement in the discharge from the tracts.

RESULTS

Fistula tracts were fully closed in 12 patients (60%). Four patients showed clinical improvement, with some tracts remaining open, and 4 patients were completely resistant to treatment. A total of 43 fistula tracts were treated during the trial, 30 of which (69.7%) showed complete closure. Histopathological analysis revealed substantial reductions in local inflammation and signs of enhanced tissue regeneration. Immunohistochemical analysis of CD68, CD20, and CD31 reaffirmed these results.

CONCLUSIONS

Mesenchymal stem cell-derived exosomes are safe and effective for treating refractory perianal fistulas in patients with Crohn's disease. See Video Abstract .

ADMINISTRACIN LOCALIZADA DE EXOSOMAS DERIVADOS DE CLULAS MADRE MESENQUIMALES PARA EL TRATAMIENTO DE LA FSTULA PERIANAL REFRACTARIA EN PACIENTES CON ENFERMEDAD DE CROHN ENSAYO CLNICO DE FASE II

ANTECEDENTES:Las fístulas perianales de la enfermedad de Crohn a menudo son resistentes a las terapias anti-TNF-α estándares. Los exosomas derivados de células madre mesenquimales (MSC) son vesículas extracelulares que tienen efectos antiinflamatorios muy potentes, y la fase anterior de este estudio demostró su seguridad en el tratamiento de fístulas perianales refractarias.OBJETIVO:Evaluar la eficacia de los exosomas derivados de MSC para el tratamiento de fístulas perianales refractarias.DISEÑO:Ensayo clínico de fase II, no aleatorizado y no ciego, unicéntrico.LUGARES:Hospital universitario terciario.PACIENTES:Se inscribieron veintitrés pacientes, 20 de los cuales completaron el estudio. La fístula perianal refractaria se definió como la resistencia a al menos un ciclo de tratamiento con terapia anti-TNF-α.INTERVENCIONES:Después de la evaluación clínica y la resonancia magnética, los pacientes fueron sometidos a anestesia general y se inyectaron 5 ml de solución de exosoma directamente en los trayectos de la fístula. Las inyecciones se repitieron tres veces a intervalos de 2 meses y los pacientes fueron seguidos mensualmente durante 6 meses después de la última inyección. Se obtuvieron muestras de tejido de los tractos antes de cada inyección y se sometieron a evaluación inmunohistopatológica. Los datos de imágenes de resonancia magnética se obtuvieron antes y seis meses después de la última inyección.PRINCIPALES MEDIDAS DE RESULTADO:El resultado primario de este estudio fue el cierre del trayecto de la fístula en el examen clínico y la imagen de resonancia magnética. El resultado secundario fue una mejora en la descarga de los tractos.RESULTADOS:Los trayectos de la fístula se cerraron completamente en 12 (60%) de los pacientes. Cuatro pacientes mostraron mejoría clínica, algunos tractos permanecieron abiertos y cuatro pacientes fueron completamente resistentes al tratamiento. Durante el ensayo se trataron un total de 43 trayectos fistulosos, 30 (69,7%) de los cuales mostraron un cierre completo. El análisis histopatológico reveló reducciones sustanciales en la inflamación local y signos de una mayor regeneración tisular. El análisis inmunohistoquímico del grupo de diferenciación 68, 20 y 31 reafirmó estos resultados.CONCLUSIONES:Los exosomas derivados de MSC son seguros y eficaces para el tratamiento de fístulas perianales refractarias en pacientes con enfermedad de Crohn. (Traducción-Dr. Aurian Garcia Gonzalez ).

Extracellular vesicle-functionalized bioactive scaffolds for bone regeneration

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

Human umbilical cord mesenchymal stem cell-derived exosomes alleviate the severity of experimental autoimmune encephalomyelitis and enhance lag-3 expression on foxp3 + CD4 + T cells

BACKGROUND

Multiple sclerosis (MS) is a complex autoimmune disease that affects the central nervous system, causing inflammation, demyelination, and neurodegeneration. Understanding the dysregulation of Tregs, dynamic cells involved in autoimmunity, is crucial in comprehending diseases like MS. However, the role of lymphocyte-activation gene 3 (Lag-3) in MS remains unclear.

METHODS

In this study, we explore the potential of exosomes derived from human umbilical cord mesenchymal stem cells (hUMSCs-Exs) as an immune modulator in experimental autoimmune encephalomyelitis (EAE), a model for MS.

RESULTS

Using flow cytometry, our research findings indicate that groups receiving treatment with hUMSC-Exs revealed a significant increase in Lag-3 expression on Foxp3 + CD4 + T cells. Furthermore, cell proliferation conducted on spleen tissue samples from EAE mice using the CFSE method exposed to hUMSC-Exs yielded relevant results.

CONCLUSIONS

These results suggest that hUMSCs-Exs could be a promising anti-inflammatory agent to regulate T-cell responses in EAE and other autoimmune diseases. However, further research is necessary to fully understand the underlying mechanisms and Lag-3's precise role in these conditions.

Mesenchymal Stem Cell-Derived Exosomes in Various Chronic Liver Diseases: Hype or Hope?

Chronic liver conditions are associated with high mortality rates and have a large adverse effect on human well-being as well as a significant financial burden. Currently, the only effective treatment available for the effects of liver failure and cirrhosis resulting from the progression of several chronic liver diseases is liver transplantation carried out at the original location. This implies that developing novel and effective treatments is imperative. Regenerative medicine has long been associated with stem cell therapy. Mesenchymal stem cells (MSCs), a type of cell with great differentiation potential, have become the preferred source for stem cell therapy. According to recent studies, MSCs' paracrine products-rather than their capacity for differentiation-play a significant therapeutic effect. MSC exosomes, a type of extracellular vesicle (MSC-EV), came into view as the paracrine substances of MSCs. According to research, MSC exosomes can maintain tissue homeostasis, which is necessary for healthy tissue function. All tissues contain them, and they take part in a variety of biological activities that support cellular activity and tissue regeneration in order to preserve tissue homeostasis. The outcomes support the use of MSCs and the exosomes they produce as a therapeutic option for a range of diseases. This review provides a brief overview of the source of MSC-EVs and outlines their physiological roles and biochemical capabilities. The elucidation of the role of MSC-EVs in the recovery and repair of hepatic tissues, as well as their contribution to maintaining tissue homeostasis, is discussed in relation to different chronic liver diseases. This review aims to provide new insights into the unique roles that MSC-EVs play in the treatment of chronic liver diseases.

Mesenchymal stem cell-derived exosomes as delivery vehicles for non-coding RNAs in lung diseases

The burden of lung diseases is gradually increasing with an increase in the average human life expectancy. Therefore, it is necessary to identify effective methods to treat lung diseases and reduce their social burden. Currently, an increasing number of studies focus on the role of mesenchymal stem cell-derived exosomes (MSC-Exos) as a cell-free therapy in lung diseases. They show great potential for application to lung diseases as a more stable and safer option than traditional cell therapies. MSC-Exos are rich in various substances, including proteins, nucleic acids, and DNA. Delivery of Non-coding RNAs (ncRNAs) enables MSC-Exos to communicate with target cells. MSC-Exos significantly inhibit inflammatory factors, reduce oxidative stress, promote normal lung cell proliferation, and reduce apoptosis by delivering ncRNAs. Moreover, MSC-Exos carrying specific ncRNAs affect the proliferation, invasion, and migration of lung cancer cells, thereby playing a role in managing lung cancer. The detailed mechanisms of MSC-Exos in the clinical treatment of lung disease were explored by developing standardized culture, isolation, purification, and administration strategies. In summary, MSC-Exo-based delivery methods have important application prospects for treating lung diseases.

Therapeutic Effects of Mesenchymal/Stromal Stem Cells and Their Derived Extracellular Vesicles in Rheumatoid Arthritis

Currently available therapies for rheumatoid arthritis (RA) are inadequate to alleviate the inflammation and reduce joint damage. While the immune-regulatory effect of human mesenchymal/stromal stem cells (MSCs) extracellular vesicles (EVs) has been tested in many inflammation-related diseases, little is known regarding their effect on patients with RA. Thus, we assessed the effect of human MSCs and MSC-EVs (from naïve or IFN-β-primed MSCs) on CD4+ T cells from patients with RA. Moreover, we investigated the effect of MSC-EVs on RA patients-derived synovial fibroblasts (FLS). MSC-EVs were prepared using a PEG precipitation followed by ultracentrifugation-based protocol. Applied to RA CD4+ T cells, EVs from IFN-β-primed MSCs, suppressed the expression of more key RA-associated cytokines (IL-4, GM-CSF IFN-γ, IL-2, TNF-α), and decreased CD4+ T-cell polyfunctionality than MSCs or EVs from naïve MSCs. MSCs mediated a slight decrease in the frequency of T-regulatory cells, while MSC-EVs rescued the frequency of T-regulatory cells. MSCs significantly inhibited CD4+ T-cell proliferation (P < .05), while no inhibition was observed in response to EV preparations. EVs from IFN-β-primed MSCs inhibited (P < .01) RA FLS migration and downregulated (P < .05) RA FLS surface markers CD34 and HLA-DR. Collectively, we demonstrated the immune-modulatory function of MSCs and their derived EVs in RA CD4+ T cells, which could be further enhanced by priming MSCs with IFN-β. Moreover, EVs from IFN-β-primed MSCs more efficiently inhibit RA FLS migration, and expression of RA FLS-related surface markers, suggesting these EVs as a potent therapy for RA.

Application of cell-derived exosomes in the hematological malignancies therapy

Exosomes are small membrane vesicles of endocytic origin that are produced by both tumor and normal cells and can be found in physiological fluids like plasma and cell culture supernatants. They include cytokines, growth factors, proteins, lipids, RNAs, and metabolites and are important intercellular communication controllers in several disorders. According to a vast amount of research, exosomes could support or inhibit tumor start and diffusion in a variety of solid and hematological malignancies by paracrine signaling. Exosomes are crucial therapeutic agents for a variety of illnesses, such as cancer and autoimmune diseases. This review discusses the most current and encouraging findings from in vitro and experimental in vivo research, as well as the scant number of ongoing clinical trials, with a focus on the impact of exosomes in the treatment of malignancies. Exosomes have great promise as carriers of medications, antagonists, genes, and other therapeutic materials that can be incorporated into their core in a variety of ways. Exosomes can also alter the metabolism of cancer cells, alter the activity of immunologic effectors, and alter non-coding RNAs, all of which can alter the tumor microenvironment and turn it from a pro-tumor to an anti-tumor milieu. This subject is covered in the current review, which also looks at how exosomes contribute to the onset and progression of hematological malignancies, as well as their importance in diagnosing and treating these conditions.

Mesenchymal Stem/Stromal Cell-Based Therapies in Systemic Rheumatic Disease: From Challenges to New Approaches for Overcoming Restrictions

Systemic rheumatic diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis, are chronic autoimmune diseases affecting multiple organs and tissues. Despite recent advances in treatment, patients still experience significant morbidity and disability. Mesenchymal stem/stromal cell (MSC)-based therapy is promising for treating systemic rheumatic diseases due to the regenerative and immunomodulatory properties of MSCs. However, several challenges need to be overcome to use MSCs in clinical practice effectively. These challenges include MSC sourcing, characterization, standardization, safety, and efficacy issues. In this review, we provide an overview of the current state of MSC-based therapies in systemic rheumatic diseases, highlighting the challenges and limitations associated with their use. We also discuss emerging strategies and novel approaches that can help overcome the limitations. Finally, we provide insights into the future directions of MSC-based therapies for systemic rheumatic diseases and their potential clinical applications.

Biogenesis, Composition and Potential Therapeutic Applications of Mesenchymal Stem Cells Derived Exosomes in Various Diseases

Exosomes are nanovesicles with a wide range of chemical compositions used in many different applications. Mesenchymal stem cell-derived exosomes (MSCs-EXOs) are spherical vesicles that have been shown to mediate tissue regeneration in a variety of diseases, including neurological, autoimmune and inflammatory, cancer, ischemic heart disease, lung injury, and liver fibrosis. They can modulate the immune response by interacting with immune effector cells due to the presence of anti-inflammatory compounds and are involved in intercellular communication through various types of cargo. MSCs-EXOs exhibit cytokine storm-mitigating properties in response to COVID-19. This review discussed the potential function of MSCs-EXOs in a variety of diseases including neurological, notably epileptic encephalopathy and Parkinson's disease, cancer, angiogenesis, autoimmune and inflammatory diseases. We provided an overview of exosome biogenesis and factors that regulate exosome biogenesis. Additionally, we highlight the functions and potential use of MSCs-EXOs in the treatment of the inflammatory disease COVID-19. Finally, we covered a strategies and challenges of MSCs-EXOs. Finally, we discuss conclusion and future perspectives of MSCs-EXOs.

Exosomes-Based Nanomedicine for Neurodegenerative Diseases: Current Insights and Future Challenges

Neurodegenerative diseases constitute a group of pathologies whose etiology remains unknown in many cases, and there are no treatments that stop the progression of such diseases. Moreover, the existence of the blood-brain barrier is an impediment to the penetration of exogenous molecules, including those found in many drugs. Exosomes are extracellular vesicles secreted by a wide variety of cells, and their primary functions include intercellular communication, immune responses, human reproduction, and synaptic plasticity. Due to their natural origin and molecular similarities with most cell types, exosomes have emerged as promising therapeutic tools for numerous diseases. Specifically, neurodegenerative diseases have shown to be a potential target for this nanomedicine strategy due to the difficult access to the brain and the strategy's pathophysiological complexity. In this regard, this review explores the most important biological-origin drug delivery systems, innovative isolation methods of exosomes, their physicochemical characterization, drug loading, cutting-edge functionalization strategies to target them within the brain, the latest research studies in neurodegenerative diseases, and the future challenges of exosomes as nanomedicine-based therapeutic tools.

Extracellular vesicles, the emerging mirrors of brain physiopathology

Extracellular vesicles are secreted by a wide variety of cells, and their primary functions include intercellular communication, immune responses, human reproduction, and synaptic plasticity. Their molecular cargo reflects the physiological processes that their cells of origin are undergoing. Thus, many studies have suggested that extracellular vesicles could be a promising biomarker tool for many diseases, mainly due to their biological relevance and easy accessibility to a broad range of body fluids. Moreover, since their biological composition leads them to cross the blood-brain barrier bidirectionally, growing evidence points to extracellular vesicles as emerging mirrors of brain diseases processes. In this regard, this review explores the biogenesis and biological functions of extracellular vesicles, their role in different physiological and pathological processes, their potential in clinical practice, and the recent outstanding studies about the role of exosomes in major human brain diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), or brain tumors.

Tumor necrosis factor-α-primed mesenchymal stem cell-derived exosomes promote M2 macrophage polarization via Galectin-1 and modify intrauterine adhesion on a novel murine model

Background

Intrauterine adhesion (IUA) is a condition caused due to damage or infection of the endometrium. It is characterized by continuous inflammation and following fibrosis and dysfunction. However, the current animal IUA models have several disadvantages, including complex operation, high mortality, and many extra distractions owing to opening of the abdominal cavity to expose the uterus. Mesenchymal stem cells (MSCs), which have been used in treatment of IUA, are heterogeneous and immunosuppressive. However, their therapeutic effect is not as good as expected.

Methods

Here, we successfully built a new murine IUA model, called electric tool-scratching IUA model, and applied it in our experiments to investigate the efficacy of tumor necrosis factor-α (TNF-α) primed MSCs (T-MSCs). In the new model, we used a self-made electric tool that can cause mechanical damage to the endometrium without opening the abdominal cavity. ELISA and histological staining analysis were performed to evaluate pathological features of IUA. qRT-PCR, flow cytometry and immunofluoresence staining were performed to detect the phenotypes of macrophages. TMT proteomics quantification and western blotting assay were performed to analyze the differentially expressed proteins of MSC exosomes.

Results

Based on the new IUA model, we found TNF-α pretreatment could enhance the ability of MSCs to relieve inflammation and reduce endometrium fibrosis. Mechanistically, T-MSC promoted macrophage polarization to M2 phenotype through exosomes. Subsequently, we found the expression of Galectin-1 was increased in T-MSC exosomes. Finally, we analyzed the gene expression pattern of Galectin-1 treated macrophages and found Galectin-1 promoted macrophage polarization to M2 phenotype mainly through the Jak-STAT signaling pathway.

Conclusions

Our studies proposed an innovative mouse model and a better MSC treatment strategy for IUA.

Evaluating the safety and efficacy of mesenchymal stem cell-derived exosomes for treatment of refractory perianal fistula in IBD patients: clinical trial phase I

BACKGROUND

Exosome administration is a novel medical approach that promises excellent immunomodulatory properties without the conventional side effects of current antitumor necrosis factor drugs and stem cells. This study aimed to assess the safety and efficacy of using mesenchymal stem cell (MSC) exosomes to treat refractory fistulas in patients with inflammatory bowel disease.

METHODS

MSCs were derived from the umbilical cords and their exosomes were isolated. Five patients with refractory perianal Crohn's disease fistulas with a median age of 35 years (range 31-47 years) were enrolled in the study. Exosome injections were administered in the operating room to patients with refractory fistula (fistulas that are irresponsive to anti-tumor necrosis factor-α administration within 6 months). Six months later, a physical examination, face-to-face interviews, and magnetic resonance imaging were employed to evaluate the therapy responses of patients.

RESULTS

The outcomes within 6 months after initiation of therapy showed that four patients had responded to therapy. Three patients who received exosome injections exhibited complete healing, while one reported no improvement and active discharge from the fistula site. In addition, five patients (100%) reported neither systemic nor local adverse effects.

CONCLUSIONS

Injection of exosomes extracted from MSCs demonstrates safety and a satisfactory therapeutic effect, as evidenced in this and other studies, and may play a significant role in the future treatment of gastrointestinal fistulas.

Mesenchymal Stem Cell-Derived Extracellular Vesicles for Therapeutic Use and in Bioengineering Applications

Extracellular vesicles (EVs) are small lipid bilayer-delimited particles that are naturally released from cells into body fluids, and therefore can travel and convey regulatory functions in the distal parts of the body. EVs can transmit paracrine signaling by carrying over cytokines, chemokines, growth factors, interleukins (ILs), transcription factors, and nucleic acids such as DNA, mRNAs, microRNAs, piRNAs, lncRNAs, sn/snoRNAs, mtRNAs and circRNAs; these EVs travel to predecided destinations to perform their functions. While mesenchymal stem cells (MSCs) have been shown to improve healing and facilitate treatments of various diseases, the allogenic use of these cells is often accompanied by serious adverse effects after transplantation. MSC-produced EVs are less immunogenic and can serve as an alternative to cellular therapies by transmitting signaling or delivering biomaterials to diseased areas of the body. This review article is focused on understanding the properties of EVs derived from different types of MSCs and MSC-EV-based therapeutic options. The potential of modern technologies such as 3D bioprinting to advance EV-based therapies is also discussed.

Autologous Stem Cells Transplants in the Treatment of Temporomandibular Joints Disorders: A Systematic Review and Meta-Analysis of Clinical Trials

This systematic review aims to analyze the outcomes of the treatment of temporomandibular joint (TMJ) articular pain (AP) and restricted maximum mouth opening (MMO) with intra-articular administration of mesenchymal stem cells (MSCs). The inclusion criteria allowed primary studies involving AP and/or MMO pre-treatment and post-intervention values. Medical databases that were covered by ACM Digital, BASE, EBSCOhost, Google Scholar, PubMed, Scopus, and Web of Science engines were searched. The risk of bias was assessed with RoB 2 and ROBINS-I tools. The results were tabulated, plotted, and analyzed for regression. A total of 5 studies involving 51 patients/69 TMJs were identified, and 4 studies on 50 patients/67 TMJs were synthesized. Interventions were each time effective in decreasing AP and increasing MMO in a 6-month follow-up period by an average of about 85% and over 40%, respectively. Regression analysis showed a good fit of the logarithmic model for AP relief (5.8 − 0.8 ln x; R² = 0.90) and MMO increase (33.5 + 2.4 ln x; R² = 0.89). The results for AP and MMO were based on 3 studies in 39 patients and 4 studies in 50 patients, respectively, all at high risk of bias. The intra-articular administration of MSCs to TMJs, based on weak evidence, may be highly effective in reducing AP and improving MMO. This study received no funding.

Mesenchymal Stem Cells-derived Exosomes Ameliorate Lupus by Inducing M2 Macrophage Polarization and Regulatory T Cell Expansion in MRL/lpr Mice

Previous studies have implicated that the transplantation of human umbilical cord mesenchymal stem cells (hUC-MSCs) effectively alleviates systemic lupus erythematosus (SLE) primarily due to immunomodulatory effects. However, little is known about the role of hUC-MSC-derived exosomes in SLE. This study is carried out to investigate the modifying effects of hUC-MSC-exosomes on the differentiation and function of immune cells in SLE. hUC-MSC-derived exosomes were extracted from the cultural supernatant of hUC-MSCs by ultrahigh speed centrifugation. Quantitative real-time polymerase chain reaction, western blot, enzyme-linked immunosorbent assay, and flow cytometry were performed to estimate the effect of hUC-MSC-derived exosomes on macrophage and regulatory T cell (Treg) polarization. In vivo, hUC-MSC-exosomes were injected intravenously into 28-week-old MRL/lpr mice. We had found that exosomes derived from hUC-MSC restrained the proliferation and inflammation of macrophages in vitro. Besides, MSC-exosomes inhibited CD68⁺M1 and HLA-DR⁺M1 but promoted CD206⁺M2 and CD163⁺M2 in vitro. Moreover, MRL/lpr mice administrated by intravenous injection of MSC-exosomes had less infiltration of CD14⁺CD11c⁺M1 cells but more CD14⁺CD163⁺M2 cells as well as Tregs in spleens compared with those in MRL/lpr mice treated by PBS. Additionally, MSC-exosomes could alleviate nephritis, liver and lung injuries of MRL/lpr mice. The survival of lupus mice could be improved after MSC-exosome treatment. This study has suggested that MSC-derived exosomes exert anti-inflammatory and immunomodulatory effects in SLE. MSC-exosomes ameliorate nephritis and other key organ injuries by inducing M2 macrophages and Tregs polarization. As natural nanocarriers, MSC-exosomes may serve as a promising cell-free therapeutic strategy for SLE.Abbreviations: SLE: Systemic lupus erythematosus; hUC-MSCs: Human umbilical cord mesenchymal stem cells; MSCs: Mesenchymal stem cells; qRT-PCR: Quantitative real-time polymerase chain reaction; ELISA: Enzyme-linked immunosorbent assay; Tregs: Regulatory cells; TNF-α: Tumor necrosis factor alfa; IL: Interleukin; COVID-19: Coronavirus disease 2019; pTHP-1: PMA-induced THP-1 macrophages; TEM: Transmission electron microscopy; LPS: Lipopolysaccharide; EVs: Extracellular vesicles; TRAF1: Tumor necrosis factor receptor-associated factor 1; IRAK1: Interferon-α-interleukin-1 receptor-associated kinase 1; NF-κB: Nuclear factor-κB; BLyS: B lymphocyte stimulator; APRIL: A proliferation-inducing ligand.

Safety and efficacy study of allogeneic human menstrual blood stromal cells secretome to treat severe COVID-19 patients: clinical trial phase I & II

BACKGROUND

Cell-free Mesenchymal stromal cells (MSCs) have been considered due to their capacity to modulate the immune system and suppress cytokine storms caused by SARS-CoV-2. This prospective randomized double-blind placebo-controlled clinical trial aimed to assess the safety and efficacy of secretome derived from allogeneic menstrual blood stromal cells (MenSCs) as a treatment in patients with severe COVID-19.

METHODS

Patients with severe COVID-19 were randomized (1:1) to either MenSC-derived secretome treatment or the control group. Subjects received five intravenous infusions of 5 mL secretome or the same volume of placebo for five days and were monitored for safety and efficacy for 28 days after treatment. Adverse events, laboratory parameters, duration of hospitalization, clinical symptom improvement, dynamic of O₂ saturation, lymphocyte number, and serial chest imaging were analyzed.

RESULTS

All safety endpoints were observed without adverse events after 72 h of secretome injection. Within 28 days after enrollment, 7 patients (50%) were intubated in the treated group versus 12 patients (80%) in the control group. Overall, 64% of patients had improved oxygen levels within 5 days of starting treatment (P < 0.0001) and there was a survival rate of 57% in the treatment group compared to 28% in the control group was (P < 0.0001). Laboratory values revealed that significant acute phase reactants declined, with mean C-reactive protein, ferritin, and D-dimer reduction of 77% (P < 0.001), 43% (P < 0.001), and 42% (P < 0.05), respectively. Significant improvement in lymphopenia was associated with an increase in mean CD4⁺ and CD8⁺ lymphocyte counts of 20% (P = 0.06) and 15% (P < 0.05), respectively. Following treatment, percentage of pulmonary involvement showed a significant improvement in the secretome group (P < 0.0001). This improvement differed significantly between survivors and those who were dying (P < 0.005).

CONCLUSIONS

For the first time, this study demonstrated that in hospitalized patients with severe COVID-19, therapy with MenSCs-derived secretome leads to reversal of hypoxia, immune reconstitution, and downregulation of cytokine storm, with no adverse effects attributable to the treatment. Given these outcomes, it may be possible to use this type of treatment for serious inflammatory lung disease with a mechanism similar to COVID-19 in the future. However, it is necessary to evaluate the safety and efficacy of MenSCs-derived secretome therapy in clinical trials on a larger population of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05019287. Registered 24AGUEST 2021, retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT05019287 . IRCT, IRCT20180619040147N6. Registered 04/01/2021.

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