Mesenchymal stem cell-derived exosomes for clinical use

Therapeutic Potential of Mesenchymal Stem Cells in PCOS

Polycystic ovary syndrome (PCOS) is a major reproductive endocrine disorder affecting different facets of a woman's life, comprising reproduction, metabolism, and mental health. Recently, several research groups have brought attention to the therapeutic capacity of mesenchymal stem cells (MSCs) for the treatment of female reproductive disorders. It is highlighted that the treatment with bone marrow mesenchymal stem cells (BMMSCs) considerably diminishes the levels of some inflammatory markers as well as essential genes for ovarian production of androgens, which are considerably higher in theca cells of PCOS women than in those of healthy cases. In addition, studies show that BMMSCs improve in vitro maturation (IVM) of germinal vesicles (GVs) and the number of antral follicles while lessening the number of primary and preantral follicles in mice with PCOS compared to healthy controls. Regarding adipose- derived mesenchymal stem cells (AdMSCs), these cells restore the ovarian structure, enhance the number of oocytes and corpora luteum, and diminish the number of aberrant cystic follicles in PCOS rats. Some research also indicates that umbilical cord mesenchymal stem cells (UC-MSCs) alleviate the inflammation of granulosa cells in women with PCOS. Therefore, due to the limited research on MSC therapy in PCOS, in this review, we summarize the current knowledge on the therapeutic potential of three types of MSCs: BMMSCs, AdMSCs, UC-MSCs and their secretome in the treatment of PCOS.

Exosomes: Friends or Foes in Microbial Infections?

The use of new approaches is necessary to address the global issue of infections caused by drug-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) is a promising approach that reduces the emergence of drug resistance, and no resistance has been reported thus far. APDT involves using a photosensitizer (PS), a light source, and oxygen. The mechanism of aPDT is that a specific wavelength of light is directed at the PS in the presence of oxygen, which activates the PS and generates reactive oxygen species (ROS), consequently causing damage to microbial cells. However, due to the PS's poor stability, low solubility in water, and limited bioavailability, it is necessary to employ drug delivery platforms to enhance the effectiveness of PS in photodynamic therapy (PDT). Exosomes are considered a desirable carrier for PS due to their specific characteristics, such as low immunogenicity, innate stability, and high ability to penetrate cells, making them a promising platform for drug delivery. Additionally, exosomes also possess antimicrobial properties, although in some cases, they may enhance microbial pathogenicity. As there are limited studies on the use of exosomes for drug delivery in microbial infections, this review aims to present significant points that can provide accurate insights.

Engineered stem cell-based strategy: A new paradigm of next-generation stem cell product in regenerative medicine

Stem cells have garnered significant attention in regenerative medicine owing to their abilities of multi-directional differentiation and self-renewal. Despite these encouraging results, the market for stem cell products yields limited, which is largely due to the challenges faced to the safety and viability of stem cells in vivo. Besides, the fate of cells re-infusion into the body unknown is also a major obstacle to stem cell therapy. Actually, both the functional protection and the fate tracking of stem cells are essential in tissue homeostasis, repair, and regeneration. Recent studies have utilized cell engineering techniques to modify stem cells for enhancing their treatment efficiency or imparting them with novel biological capabilities, in which advances demonstrate the immense potential of engineered cell therapy. In this review, we proposed that the "engineered stem cells" are expected to represent the next generation of stem cell therapies and reviewed recent progress in this area. We also discussed potential applications of engineered stem cells and highlighted the most common challenges that must be addressed. Overall, this review has important guiding significance for the future design of new paradigms of stem cell products to improve their therapeutic efficacy.

Extracellular vesicles from induced pluripotent stem cell-derived mesenchymal stem cells enhance the recovery of acute kidney injury

BACKGROUND AIMS

To investigate whether the extracellular vesicles (EVs) from mesenchymal stem cell-like cells derived from induced pluripotent stem cells (iMSC-EVs) can inhibit the progression of acute kidney injury (AKI).

METHODS

The characteristics of iMSC-EVs were confirmed by immunoblotting, cryo-transmission electron microscopy, nanoparticle tracking analysis, and their localization in kidneys. Using human renal epithelial cells, the potential of iMSC-EVs to stimulate the growth and survival of HK-2 cells undergoing cisplatin-induced cell death was investigated. The anti-inflammatory effects of iMSC-EVs was examined in M1-polarized THP-1 macrophages. Subsequently, the therapeutic potential of iMSC-EVs was assessed in cisplatin-induced acute kidney injury in BALB/c mice. The anti-apoptotic and anti-inflammatory effect of iMSC-EVs was evaluated using serum biochemistry, histology, immunohistochemistry, and gene expression analysis.

RESULTS

iMSC-EVs promoted the growth of renal epithelial cell (HK-2) and enhanced the survival of HK-2 undergoing cisplatin-induced cell death. In cisplatin-induced mice with AKI, iMSC-EVs alleviated AKI, as shown by reduced blood nitrogen urea/creatinine and increased body weight. Also, iMSC-EVs enhanced renal tissue integrity and the number of proliferating cell nuclear antigen-positive tubules. iMSC-EVs decreased the infiltration of immune cells, reduced the expression of inflammatory genes in M1-induced THP-1 cells and enhanced capillary density in the kidney of AKI mice. Real-time quantitative polymerase chain reaction analysis showed that the expression of inflammatory genes in the kidney of AKI mice was reduced compared with that received vehicle. Immunoblotting revealed that iMSC-EVs led to a decreased protein expression of key inflammatory genes. Also, iMSC-EVs reversed the activation of ERK1/2 signaling induced by AKI. Finally, iMSC-EVs inhibited the apoptosis of HK-2 cells induced by cisplatin as well as that of renal tissue of AKI mice.

CONCLUSIONS

Our data suggest that iMSC-EVs have potential to become a novel, cell-free therapeutic for cisplatin-induced AKI.

Treatment with Exosomes Derived from Mesenchymal Stem Cells: A New Window of Healing Science in Regenerative Medicine

Many studies have been conducted on the potential applications of mesenchymal stem cells (MSCs) over recent years due to their growing importance in regenerative medicine. Exosomes are considered cargos capable of transporting proteins, peptides, lipids, mRNAs, and growth factors. MSCsderived exosomes are also involved in the prevention or treatment of a variety of diseases, including cardiovascular diseases, neurological diseases, skin disorders, lung diseases, osteoarthritis, damaged tissue repair, and other diseases. This review attempted to summarize the importance of employing MSCs in regenerative medicine by gathering and evaluating information from current literature. The role of MSCs and the potential applications of MSCs-derived exosomes have also been discussed.

Adipose-Derived Stem Cell Exosomes Alleviate Psoriasis Serum Exosomes-Induced Inflammation by Regulating Autophagy and Redox Status in Keratinocytes

Introduction

Exosomes play a key role in cell communication and are involved in both pathological and physiological processes. Autophagy dysfunction and oxidative stress are linked to immune-mediated inflammatory diseases such as psoriasis. Stem cell-derived exosomes exhibit immunomodulatory and antioxidant efficacy.

Methods

We aimed to investigate the impact of psoriasis serum-derived exosomes on inflammation, oxidative stress, and autophagy in keratinocytes. Additionally, we explored the therapeutic potential of adipose-derived stem cell (ADSC) exosomes against inflammation induced by psoriasis serum exosomes. To validate psoriasis patient serum-derived exosomes and ADSC exosomes, we used nanoparticle tracking analysis, Western blotting, flow cytometry, and immunofluorescence. qPCR was used to study changes in the gene expression of proinflammatory cytokines and oxidative stress markers in HaCaT cells treated with psoriasis serum-derived exosomes or ADSC exosomes. The effects of these exosomes on autophagy in HaCaT cells were evaluated by Western blotting and immunofluorescence.

Result

The treatment of HaCaT cells with psoriasis serum-derived exosomes increased proinflammatory cytokine production and oxidative stress-related factor (Nox2 and Nox4) expression and decreased Nrf2 expression via P65/NF-κB and P38/MAPK activation. Compared with healthy control serum-derived exosomes, psoriasis serum-derived exosomes decreased ATG5, P62, Beclin1, and LC3 expression and autophagosome production in HaCaT cells. Conversely, ADSC exosomes suppressed proinflammatory cytokine and oxidative stress production, and restored autophagy in HaCaT cells treated with psoriasis serum-derived exosomes.

Discussion

These findings suggest that ADSC exosomes exhibit a suppressive effect on psoriasis serum exosome-induced inflammation and oxidative stress by regulating autophagy in keratinocytes.

The emerging role of exosomes in communication between the periphery and the central nervous system

Exosomes, membrane-enclosed vesicles, are secreted by all types of cells. Exosomes can transport various molecules, including proteins, lipids, functional mRNAs, and microRNAs, and can be circulated to various recipient cells, leading to the production of local paracrine or distal systemic effects. Numerous studies have proved that exosomes can pass through the blood-brain barrier, thus, enabling the transfer of peripheral substances into the central nervous system (CNS). Consequently, exosomes may be a vital factor in the exchange of information between the periphery and CNS. This review will discuss the structure, biogenesis, and functional characterization of exosomes and summarize the role of peripheral exosomes deriving from tissues like the lung, gut, skeletal muscle, and various stem cell types in communicating with the CNS and influencing the brain's function. Then, we further discuss the potential therapeutic effects of exosomes in brain diseases and the clinical opportunities and challenges. Gaining a clearer insight into the communication between the CNS and the external areas of the body will help us to ascertain the role of the peripheral elements in the maintenance of brain health and illness and will facilitate the design of minimally invasive techniques for diagnosing and treating brain diseases.

The effects of intracellular and exosomal ncRNAs on cancer progression

Altered gene expression as well as mislocalization of a gene's encoded product (proteins or noncoding RNAs (ncRNAs)) can lead to disease and cancer formation. Multiple studies have indicated that exosomes and their contents act as cell-to-cell communicators and play a key role in cancer progression. Moreover, exosomes contain several functional molecules, including ncRNAs. NcRNAs function as master regulators to coordinate cell growth, cell motility and drug resistance. However, intracellular ncRNAs, which can be transferred to recipient cells via exosomes (exosomal ncRNAs), mediate common/distinct downstream molecules, signaling pathways and functions that are less emphasized concepts in cancer development research. In this study, by using exosomes as a model, we comprehensively discuss the current knowledge regarding (1) the functional role of ncRNAs, both their intracellular and exosomal forms, in cancer progression, (2) the possible mechanism of ncRNA incorporation into exosomes and (3) the therapeutic applications and limitations of exosomes based on current knowledge.

Regeneration and anti-inflammatory effects of stem cells and their extracellular vesicles in gynecological diseases

There are many gynecological diseases, among which breast cancer (BC), cervical cancer (CC), endometriosis (EMs), and polycystic ovary syndrome (PCOS) are common and difficult to cure. Stem cells (SCs) are a focus of regenerative medicine. They are commonly used to treat organ damage and difficult diseases because of their potential for self-renewal and multidirectional differentiation. SCs are also commonly used for difficult-to-treat gynecological diseases because of their strong directional differentiation ability with unlimited possibilities, their tendency to adhere to the diseased tissue site, and their use as carriers for drug delivery. SCs can produce exosomes in a paracrine manner. Exosomes can be produced in large quantities and have the advantage of easy storage. Their safety and efficacy are superior to those of SCs, which have considerable potential in gynecological treatment, such as inhibiting endometrial senescence, promoting vascular reconstruction, and improving anti-inflammatory and immune functions. In this paper, we review the mechanisms of the regenerative and anti-inflammatory capacity of SCs and exosomes in incurable gynecological diseases and the current progress in their application in genetic engineering to provide a foundation for further research.

Protective effects of EVs/exosomes derived from permanently growing human MSC on primary murine ALS motor neurons

In recent years, the neuroprotective potential of mesenchymal stroma-/stem-like cells (MSC) as well as of MSC-derived extracellular vesicles (EVs) like exosomes has been intensively explored. This included preclinical evaluation regarding treatment of neurodegenerative disorders such as the fatal motor neuron disease amyotrophic Lateral Sclerosis (ALS). Several studies have reported that MSC-derived exosomes can stimulate tissue regeneration and reduce inflammation. MSC release EVs and trophic factors and thereby modify cell-to-cell communication. These cell-free products may protect degenerating motor neurons (MNs) and represent a potential therapeutic approach for ALS. In the present study we investigated the effects of exosomes derived from a permanently growing MSC line on both, wild type and ALS (SOD1G93A transgenic) primary motor neurons. Following application in a normal and stressed environment we could demonstrate beneficial effects of MSC exosomes on neurite growth and morphology indicating the potential for further preclinical evaluation and clinical therapeutic development. Investigation of gene expression profiles detected transcripts of several antioxidant and anti-inflammatory genes in MSC exosomes. Characterization of their microRNA (miRNA) content revealed miRNAs capable of regulating antioxidant and anti-apoptotic pathways.

Analysis of distribution, collection, and confirmation of capacity dependency of small extracellular vesicles toward a therapy for liver cirrhosis

BACKGROUND

The progression of liver fibrosis leads to portal hypertension and liver dysfunction. However, no antifibrotic agents have been approved for cirrhosis to date, making them an unmet medical need. Small extracellular vesicles (sEVs) of mesenchymal stem cells (MSCs) are among these candidate agents. In this study, we investigated the effects of sEVs of MSCs, analyzed their distribution in the liver post-administration, whether their effect was dose-dependent, and whether it was possible to collect a large number of sEVs.

METHODS

sEVs expressing tdTomato were generated, and their uptake into constituent liver cells was observed in vitro, as well as their sites of uptake and cells in the liver using a mouse model of liver cirrhosis. The efficiency of sEV collection using tangential flow filtration (TFF) and changes in the therapeutic effects of sEVs in a volume-dependent manner were examined.

RESULTS

The sEVs of MSCs accumulated mostly in macrophages in damaged areas of the liver. In addition, the therapeutic effect of sEVs was not necessarily dose-dependent, and it reached a plateau when the dosage exceeded a certain level. Furthermore, although ultracentrifugation was commonly used to collect sEVs for research purposes, we verified that TFF could be used for efficient sEV collection and that their effectiveness is not reduced.

CONCLUSION

In this study, we identified some unknown aspects regarding the dynamics, collection, and capacity dependence of sEVs. Our results provide important fundamentals for the development of therapies using sEVs and hold potential implications for the therapeutic applications of sEV-based therapies for liver cirrhosis.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Efficacy of Mesenchymal Stem Cell-Derived Extracellular Vesicles in the Animal Model of Female Reproductive Diseases: A Meta-Analysis

BACKGROUND

Female reproductive disorders, such as premature ovarian insufficiency (POI), intrauterine adhesion (IUA) or thin endometrium, and polycystic ovary syndrome (PCOS), are the main factors affecting fertility. Mesenchymal stem cells derived-extracellular vesicles (MSC-EVs) have gained traction as a new potential treatment and were widely studied in these diseases. However, their impact is still not fully clear.

METHODS

A systematic search of PubMed, Web of Science, EMBASE, the Chinese National Knowledge of Infrastructure, and WanFang online databases was performed up to September 27th, 2022, and the studies of MSC-EVs-based therapy on the animal models of female reproductive diseases were included. The primary outcomes were anti-Müllerian hormone (AMH) in POI and endometrial thickness in IUA, respectively.

RESULTS

28 studies (POI, N = 15; IUA, N = 13) were included. For POI, MSC-EVs improved AMH at 2 weeks (SMD 3.40, 95% CI 2.02 to 4.77) and 4 weeks (SMD 5.39, 95% CI 3.43 to 7.36) compared with placebo, and no difference was found when compared with MSCs in AMH (SMD -2.03, 95% CI -4.25 to 0.18). For IUA, MSC-EVs treatment could increase the endometrial thickness at 2 weeks (WMD 132.36, 95% CI 118.99 to 145.74), but no improvement was found at 4 weeks (WMD 166.18, 95% CI -21.44 to 353.79). The combination of MSC-EVs with hyaluronic acid or collagen had a better effect on the endometrial thickness (WMD 105.31, 95% CI 85.49 to 125.13) and glands (WMD 8.74, 95% CI 1.34 to 16.15) than MSC-EVs alone. The medium dose of EVs may allow for great benefits in both POI and IUA.

CONCLUSIONS

MSC-EVs treatment could improve the functional and structural outcomes in female reproductive disorders. The combination of MSC-EVs with HA or collagen may enhance the effect. These findings can accelerate the translation of MSC-EVs treatment to human clinical trials.

Exosomes from magnetic particles-primed mesenchymal stem cells enhance neural differentiation of PC12 cells

This study aimed to investigate the effects of mesenchymal stem cell exosomes loaded with Fe3O4 magnetic particles (Fe3O4@ MSC-exo) on the survival and neural differentiation of PC12 cells. Exosomes were separated from Fe3O4 magnetic nanoparticles-primed umbilical cord mesenchymal stem cells condition medium by ultracentrifugation and characterized by transmission electron microscopy, flow nano analysis, and western blotting. PC12 cells were treated with culture medium containing exosomes. The effects of Fe3O4@ MSC-exo on PC12 cell proliferation, migration, and neural differentiation were analyzed using CCK-8 assay, transwell migration assay, RT-qPCR, and immunofluorescence, respectively. Additionally, miRNA sequencing was performed on Fe3O4@ MSC-exo, followed by bioinformatic analysis of the results. We found that Fe3O4@ MSC-exo can promote PC12 cell proliferation, migration, and neural differentiation. According to the sequencing results, there were a total of 43 differentially expressed miRNAs. The present study indicated that Fe3O4@ MSC-exo might enhance nerve cell function, laying the foundation for targeted therapy of nerve injury.

HSF1 enhances the attenuation of exosomes from mesenchymal stem cells to hemorrhagic shock induced lung injury by altering the protein profile of exosomes

Severe hemorrhagic shock (HS) leads to lung injury, resulting in respiratory insufficiency. Mesenchymal stem cell (MSC)-derived exosomes have therapeutic effects on the organ injury. HSF1 has been reported to protect the lung against injury. In this study, the role of exosomes from HSF1-overexpressed MSCs (HSF1-EVs) in HS-induced lung injury was investigated. We constructed a mouse model of lung injury by induction with HS and pre-treated it with HSF1-EVs. It was clarified that HSF1-EVs manifested better protective effects on HS-induced lung injury compared with the exosomes derived from control MSCs. Inhalation of HSF1-EVs declined the ratio of wet to dry and total protein concentration in bronchoalveolar lavage fluids. Besides, HSF1-EVs greatly inhibited the production of inflammatory cytokines (IL-1β, IL-6, MCP-1 and HMGB1), and constrained the pulmonary neutrophilic infiltration induced by HS. A reduction of oxidative stress was observed in HSF1-EV-treated mice. HSF1-EVs suppressed the HS-induced apoptosis of lung cell and downregulated Bcl-2 expression, while promoting Bax expression. The key proteins of pulmonary epithelial barrier, E-cadherin, ZO-1 and Occludin, were all upregulated in HS-treated mice after HSF1-EV inhalation, suggesting that HSF1-EVs played a protective role in the epithelial barrier of lung. Additionally, the results of proteomics showed that HSF1 overexpression altered the protein profile of MSC-derived exosomes, which might explain the more significant relief effect of HSF1-EVs on lung injury compared with that of Plasmid-EVs. These new findings demonstrated that the exosomes secreted by HSF1-overexpressed MSCs can be an effective precautionary measure for lung injury induced by HS.

Host and Pathogen-Directed Therapies against Microbial Infections Using Exosome- and Antimicrobial Peptide-derived Stem Cells with a Special look at Pulmonary Infections and Sepsis

Microbial diseases are a great threat to global health and cause considerable mortality and extensive economic losses each year. The medications for treating this group of diseases (antibiotics, antiviral, antifungal drugs, etc.) directly attack the pathogenic agents by recognizing the target molecules. However, it is necessary to note that excessive use of any of these drugs can lead to an increase in microbial resistance and infectious diseases. New therapeutic methods have been studied recently using emerging drugs such as mesenchymal stem cell-derived exosomes (MSC-Exos) and antimicrobial peptides (AMPs), which act based on two completely different strategies against pathogens including Host-Directed Therapy (HDT) and Pathogen-Directed Therapy (PDT), respectively. In the PDT approach, AMPs interact directly with pathogens to interrupt their intrusion, survival, and proliferation. These drugs interact directly with the cell membrane or intracellular components of pathogens and cause the death of pathogens or inhibit their replication. The mechanism of action of MSC-Exos in HDT is based on immunomodulation and regulation, promotion of tissue regeneration, and reduced host toxicity. This review studies the potential of mesenchymal stem cell-derived exosomes/ATPs therapeutic properties against microbial infectious diseases especially pulmonary infections and sepsis.

Advanced micro-/nanotechnologies for exosome encapsulation and targeting in regenerative medicine

Exosomes, a subset of vesicles generated from cell membranes, are crucial for cellular communication. Exosomes' innate qualities have been used in recent studies to create nanocarriers for various purposes, including medication delivery and immunotherapy. As a result, a wide range of approaches has been designed to utilize their non-immunogenic nature, drug-loading capacity, or targeting ability. In this study, we aimed to review the novel methods and approaches in exosome engineering for encapsulation and targeting in regenerative medicine. We have assessed and evaluated each method's efficacy, advantages, and disadvantages and discussed the results of related studies. Even though the therapeutic role of non-allogenic exosomes has been demonstrated in several studies, their application has certain limitations as these particles are neither fully specific to target tissue nor tissue retainable. Hence, there is a strong demand for developing more efficient encapsulation methods along with more accurate and precise targeting methods, such as 3D printing and magnetic nanoparticle loading in exosomes, respectively.

Stem cells-derived exosomes alleviate neurodegeneration and Alzheimer's pathogenesis by ameliorating neuroinflamation, and regulating the associated molecular pathways

Amyloid beta (Aβ) aggregation and tau hyper phosphorylation (p-tau) are key molecular factors in Alzheimer's disease (AD). The abnormal formation and accumulation of Aβ and p-tau lead to the formation of amyloid plaques and neurofibrillary tangles (NFTs) which ultimately leads to neuroinflammation and neurodegeneration. β- and γ-secretases produce Aβ peptides via the amyloidogenic pathway, and several kinases are involved in tau phosphorylation. Exosomes, a recently developed method of intercellular communication, derived from neuronal stem cells (NSC-exos), are intriguing therapeutic options for AD. Exosomes have ability to cross the BBB hence highly recommended for brain related diseases and disorders. In the current study, we examined how NSC-exos could protect human neuroblastoma cells SH-SY5Y (ATCC CRL-2266). NSC-exos were derived from Human neural stem cells (ATCC-BYS012) by ultracentrifugation and the therapeutic effects of the NSC-exos were then investigated in vitro. NSC-exos controlled the associated molecular processes to drastically lower Aβ and p-tau. A dose dependent reduction in β- and γ-secretase, acetylcholinesterase, GSK3β, CDK5, and activated α-secretase activities was also seen. We further showed that BACE1, PSEN1, CDK5, and GSK-3β mRNA expression was suppressed and downregulated, while ADAM10 mRNA was increased. NSC- Exos downregulate NF-B/ERK/JNK-related signaling pathways in activated glial cells HMC3 (ATCC-CRL-3304) and reduce inflammatory mediators such iNOS, IL-1β, TNF-α, and IL-6, which are associated with neuronal inflammation. The NSC-exos therapy ameliorated the neurodegeneration of human neuroblastoma cells SH-SY5Y by enhancing viability. Overall, these findings support that exosomes produced from stem cells can be a neuro-protective therapy to alleviate AD pathology.

Cell-free therapy based on extracellular vesicles: a promising therapeutic strategy for peripheral nerve injury

Peripheral nerve injury (PNI) is one of the public health concerns that can result in a loss of sensory or motor function in the areas in which injured and non-injured nerves come together. Up until now, there has been no optimized therapy for complete nerve regeneration after PNI. Exosome-based therapies are an emerging and effective therapeutic strategy for promoting nerve regeneration and functional recovery. Exosomes, as natural extracellular vesicles, contain bioactive molecules for intracellular communications and nervous tissue function, which could overcome the challenges of cell-based therapies. Furthermore, the bioactivity and ability of exosomes to deliver various types of agents, such as proteins and microRNA, have made exosomes a potential approach for neurotherapeutics. However, the type of cell origin, dosage, and targeted delivery of exosomes still pose challenges for the clinical translation of exosome therapeutics. In this review, we have focused on Schwann cell and mesenchymal stem cell (MSC)-derived exosomes in nerve tissue regeneration. Also, we expressed the current understanding of MSC-derived exosomes related to nerve regeneration and provided insights for developing a cell-free MSC therapeutic strategy for nerve injury.

In Vitro Insights Into the Influence of Marrow Mesodermal/Mesenchymal Progenitor Cells on Acute Myelogenous Leukemia and Myelodysplastic Syndromes

The study of marrow-resident mesodermal progenitors can provide important insight into their role in influencing normal and aberrant hematopoiesis as occurs in acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS). In addition, the chemokine competency of these cells provides links to the inflammatory milieu of the marrow microenvironment with additional implications for normal and malignant hematopoiesis. While in vivo studies have elucidated the structure and function of the marrow niche in murine genetic models, corollary human studies have not been feasible, and thus the use of culture-adapted mesodermal cells has provided insights into the role these rare endogenous niche cells play in physiologic, malignant, and inflammatory states. This review focuses on culture-adapted human mesenchymal stem/stromal cells (MSCs) as they have been utilized in understanding their influence in AML and MDS as well as on their chemokine-mediated responses to myeloid malignancies, injury, and inflammation. Such studies have intrinsic limitations but have provided mechanistic insights and clues regarding novel druggable targets.

A comprehensive review on the composition, biogenesis, purification, and multifunctional role of exosome as delivery vehicles for cancer therapy

All forms of life produce nanosized extracellular vesicles called exosomes, which are enclosed in lipid bilayer membranes. Exosomes engage in cell-to-cell communication and participate in a variety of physiological and pathological processes. Exosomes function via their bioactive components, which are delivered to target cells in the form of proteins, nucleic acids, and lipids. Exosomes function as drug delivery vehicles due to their unique properties of innate stability, low immunogenicity, biocompatibility, biodistribution, accumulation in desired tissues, low toxicity in normal tissues, and the stimulation of anti-cancer immune responses, and penetration capacity into distance organs. Exosomes mediate cellular communications by delivering various bioactive molecules including oncogenes, oncomiRs, proteins, specific DNA, messenger RNA (mRNA), microRNA (miRNA), small interfering RNA (siRNA), and circular RNA (circRNA). These bioactive substances can be transferred to change the transcriptome of target cells and influence tumor-related signaling pathways. After considering all of the available literature, in this review we discuss the biogenesis, composition, production, and purification of exosomes. We briefly review exosome isolation and purification techniques. We explore great-length exosomes as a mechanism for delivering a variety of substances, including proteins, nucleic acids, small chemicals, and chemotherapeutic drugs. We also talk about the benefits and drawbacks of exosomes. This review concludes with a discussion future perspective and challenges. We hope that this review will provide us a better understanding of the current state of nanomedicine and exosome applications in biomedicine.

Exosomes from TNF-α preconditioned human umbilical cord mesenchymal stromal cells inhibit the autophagy of acinar cells of severe acute pancreatitis via shuttling bioactive metabolites

Severe acute pancreatitis (SAP) is a common critical disease of the digestive system, with high mortality and a lack of effective prevention and treatment measures. Despite mesenchymal stromal cell transplantation having the potential to treat SAP, its clinical application prospect is limited, and the mechanism is unclear. Here, we reveal the therapeutic role of exosomes from TNF-α-preconditioned human umbilical cord mesenchymal stromal cells (HUCMSCs) in attenuating SAP and show that it is partly dependent on exosomal metabolites. Bioactive metabolomics analysis showed that 48 metabolites be significantly differentially expressed between the two groups (Exo-Ctrl group versus Exo-TNF-α group). Then, the further functional experiments indicated that 3,4-dihydroxyphenylglycol could be a key molecule mediating the therapeutic effect of TNF-α-preconditioned HUCMSCs. The animal experiments showed that 3,4-dihydroxyphenylglycol reduced inflammation and oxidative stress in the pancreatic tissue and inhibited acinar cell autophagy in a rat model of SAP. Mechanistically, we revealed that 3,4-dihydroxyphenylglycol activated the mTOR pathway to inhibit acinar cell autophagy and alleviate SAP. In summary, our study demonstrated that exosomes from TNF-α-preconditioned HUMSCs inhibit the autophagy of acinar cells of SAP by shuttling 3,4-dihydroxyphenylglycol and inhibiting the mTOR pathway. This study revealed the vital role and therapeutic potential of metabolite-derived exosomes in SAP, providing a new promising method to prevent and therapy SAP.

Breast Milk Mesenchymal Stem Cells and/or Derived Exosomes Mitigated Adenine-Induced Nephropathy via Modulating Renal Autophagy and Fibrotic Signaling Pathways and Their Epigenetic Regulations

Chronic kidney disease (CKD), a global health concern, is highly prevalent among adults. Presently, there are limited therapeutic options to restore kidney function. This study aimed to investigate the therapeutic potential of breast milk mesenchymal stem cells (Br-MSCs) and their derived exosomes in CKD. Eighty adult male Sprague Dawley rats were randomly assigned to one of six groups, including control, nephropathy, nephropathy + conditioned media (CM), nephropathy + Br-MSCs, nephropathy + Br-MSCs derived exosomes (Br-MSCs-EXOs), and nephropathy + Br-MSCs + Br-MSCs-EXOs. Before administration, Br-MSCs and Br-MSCs-EXOs were isolated, identified, and labeled with PKH-26. SOX2, Nanog, and OCT3/4 expression levels in Br-MSCs and miR-29b, miR-181, and Let-7b in both Br-MSCs and Br-MSCs-EXOs were assayed. Twelve weeks after transplantation, renal function tests, oxidative stress, expression of the long non-coding RNA SNHG-7, autophagy, fibrosis, and expression of profibrotic miR-34a and antifibrotic miR-29b, miR-181, and Let-7b were measured in renal tissues. Immunohistochemical analysis for renal Beclin-1, LC3-II, and P62, Masson trichome staining, and histopathological examination of kidney tissues were also performed. The results showed that Br-MSCs expressed SOX2, Nanog, and OCT3/4, while both Br-MSCs and Br-MSCs-EXOs expressed antifibrotic miR-181, miR-29b, and Let-7b, with higher expression levels in exosomes than in Br-MSCs. Interestingly, the administration of Br-MSCs + EXOs, EXOs, and Br-MSCs improved renal function tests, reduced renal oxidative stress, upregulated the renal expression of SNHG-7, AMPK, ULK-1, Beclin-1, LC3, miR-29b, miR-181, Let-7b, and Smad-7, downregulated the renal expression of miR-34a, AKT, mTOR, P62, TGF-β, Smad-3, and Coli-1, and ameliorated renal pathology. Thus, Br-MSCs and/or their derived exosomes appear to reduce adenine-induced renal damage by secreting antifibrotic microRNAs and potentiate renal autophagy by modulating SNHG-7 expression.

The role of MSCs and CAR-MSCs in cellular immunotherapy

Chimeric antigen receptors (CARs) are widely used by T cells (CAR-T cells), natural killer cells dendritic cells and macrophages, and they are of great importance in cellular immunotherapy. However, the use of CAR-related products faces several challenges, including the poor persistence of cells carrying CARs, cell dysfunction or exhaustion, relapse of disease, immune effector cell-associated neurotoxicity syndrome, cytokine release syndrome, low efficacy against solid tumors and immunosuppression by the tumor microenvironment. Another important cell therapy regimen involves mesenchymal stem cells (MSCs). Recent studies have shown that MSCs can improve the anticancer functions of CAR-related products. CAR-MSCs can overcome the flaws of cellular immunotherapy. Thus, MSCs can be used as a biological vehicle for CARs. In this review, we first discuss the characteristics and immunomodulatory functions of MSCs. Then, the role of MSCs as a source of exosomes, including the characteristics of MSC-derived exosomes and their immunomodulatory functions, is discussed. The role of MSCs in CAR-related products, CAR-related product-derived exosomes and the effect of MSCs on CAR-related products are reviewed. Finally, the use of MSCs as CAR vehicles is discussed. Video Abstract.

Characteristics of mesenchymal stem cells and their exosomes derived from giant panda (Ailuropoda melanoleuca) endometrium

Conservation of genetic resources is an important way to protect endangered species. At present, mesenchymal stem cells (MSCs) have been isolated from the bone marrow and umbilical cords of giant pandas. However, the types and quantities of preserved cell resources were rare and limited, and none of MSCs was derived from female reproductive organs. Here, we first isolated MSCs from the endometrium of giant panda. These cells showed fibroblast morphology and expressed Sox2, Klf4, Thy1, CD73, CD105, CD44, CD49f, and CD105. Endometrium mesenchymal stem cells (eMSCs) of giant panda could induce differentiation into three germ layers in vitro. RNA-seq analysis showed that 833 genes were upregulated and 716 genes were downregulated in eMSCs compared with skin fibroblast cells. The results of GO and the KEGG analysis of differentially expressed genes (DEGs) were mainly focused on transporter activity, signal transducer activity, pathways regulating pluripotency of stem cells, MAPK signaling pathway, and PI3K-Akt signaling pathway. The genes PLCG2, FRK, JAK3, LYN, PIK3CB, JAK2, CBLB, and MET were identified as hub genes by PPI network analysis. In addition, the exosomes of eMSCs were also isolated and identified. The average diameter of exosomes was 74.26 ± 13.75 nm and highly expressed TSG101 and CD9 but did not express CALNEXIN. A total of 277 miRNAs were detected in the exosomes; the highest expression of miRNA was the has-miR-21-5p. A total of 14461 target genes of the whole miRNAs were predicted and proceeded with functional analysis. In conclusion, we successfully isolated and characterized the giant panda eMSCs and their exosomes, and analyzed their functions through bioinformatics techniques. It not only enriched the conservation types of giant panda cell resources and promoted the protection of genetic diversity, but also laid a foundation for the application of eMSCs and exosomes in the disease treatment of giant pandas.

Intranasally Administered MSC-Derived Extracellular Vesicles Reverse Cisplatin-Induced Cognitive Impairment

Neurotoxic side effects of chemotherapy include deficits in attention, memory, and executive functioning. Currently, there are no FDA-approved therapies. In mice, cisplatin causes long-term cognitive deficits, white matter damage, mitochondrial dysfunction, and loss of synaptic integrity. We hypothesized that MSC-derived small extracellular vesicles (sEVs) could restore cisplatin-induced cognitive impairments and brain damage. Animals were injected with cisplatin intraperitoneally and treated with MSC-derived sEVs intranasally 48 and 96 h after the last cisplatin injection. The puzzle box test (PBT) and the novel object place recognition test (NOPRT) were used to determine cognitive deficits. Synaptosomal mitochondrial morphology was analyzed by transmission electron microscopy. Immunohistochemistry using antibodies against synaptophysin and PSD95 was applied to assess synaptic loss. Black-Gold II staining was used to quantify white matter integrity. Our data show that sEVs enter the brain in 30 min and reverse the cisplatin-induced deficits in executive functioning and working and spatial memory. Abnormalities in mitochondrial morphology, loss of white matter, and synaptic integrity in the hippocampus were restored as well. Transcriptomic analysis revealed upregulation of regenerative functions after treatment with sEVs, pointing to a possible role of axonal guidance signaling, netrin signaling, and Wnt/Ca²⁺ signaling in recovery. Our data suggest that intranasal sEV treatment could become a novel therapeutic approach for the treatment of chemobrain.

Recent Insights into Noncoding RNAs in Primary Ovarian Insufficiency: Focus on Mechanisms and Treatments

CONTEXT

Primary ovarian insufficiency (POI) is a heterogeneous disease with an unknown underlying trigger or root cause. Recently many studies evaluated noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNA (lncRNAs), circular RNAs (circRNAs), and small interfering RNAs (siRNAs) for their associations with POI.

EVIDENCE ACQUISITION

In this review, we outline the biogenesis of various ncRNAs relevant to POI and summarize the evidence for their roles in the regulation of disease occurrence and progression. Articles from 2003 to 2022 were selected for relevance, validity, and quality from results obtained in PubMed and Google Scholar using the following search terms: noncoding RNAs; primary ovarian insufficiency; premature ovarian failure; noncoding RNAs and primary ovarian insufficiency/premature ovarian failure; miRNAs and primary ovarian insufficiency/premature ovarian failure; lncRNAs and primary ovarian insufficiency/premature ovarian failure; siRNAs and primary ovarian insufficiency/premature ovarian failure; circRNAs and primary ovarian insufficiency/premature ovarian failure; pathophysiology; and potential treatment. All articles were independently screened for eligibility by the authors.

EVIDENCE SYNTHESIS

This review summarizes the biological functions and synthesis of miRNAs, lncRNAs, siRNAs, and circRNAs in POI and discusses the findings of clinical and in vitro and in vivo studies. Although there is variability in the findings of individual studies, overall the available literature justifies the conclusion that dysregulated ncRNAs play significant roles in POI.

CONCLUSION

The potential of ncRNAs in the treatment of POI requires further investigation, as ncRNAs derived from mesenchymal stem cell-secreted exosomes play pivotal roles and have considerable therapeutic potential in a multitude of diseases.

Therapeutic Benefits of Stem Cells and Exosomes for Sulfur-Mustard-Induced Tissue Damage

Sulfur mustard (SM) is a highly toxic chemical agent that causes severe tissue damage, particularly to the eyes, lungs, and skin. Despite advances in treatment, there is a need for more effective therapies for SM-induced tissue injury. Stem cell and exosome therapies are emerging as promising approaches for tissue repair and regeneration. Stem cells can differentiate into multiple cell types and promote tissue regeneration, while exosomes are small vesicles that can deliver therapeutic cargo to target cells. Several preclinical studies demonstrated the potential of stem cell, exosome, or combination therapy for various tissue injury, showing improvements in tissue repairing, inflammation, and fibrosis. However, there are also challenges associated with these therapies, such as the requirement for standardized methods for exosome isolation and characterization, the long-term safety and efficacy and reduced SM-induced tissue injury of these therapies. Stem cell or exosome therapy was used for SM-induced eye and lung injury. Despite the limited data on the use for SM-induced skin injury, this therapy is a promising area of research and may offer new treatment options in the future. In this review, we focused on optimizing these therapies, evaluating their safety and efficacy, and comparing their efficacy to other emerging therapeutic approaches potentially for SM-induced tissue injury in the eye, lung, and skin.

Deciphering the Heterogeneity Landscape of Mesenchymal Stem/Stromal Cell-Derived Extracellular Vesicles for Precise Selection in Translational Medicine

Mesenchymal stem/stromal cell-derived extracellular vesicles (MSC-EVs) have been considered promising therapeutics for disease treatments. However, MSC-EVs harvested from different tissues present unique biological features reflective of their origins. The heterogeneity of MSC-EVs constitutes an important barrier to their precise application in clinical translation that may probably lead to uncertain therapeutic effects. To give hints for future clinical translation, five MSCs are employed, whose derived EVs are most intensively utilized, namely bone marrow mesenchymal stem/stromal cells (BMMSCs), umbilical cord stem/stromal cells (UCSCs), adipose-derived stem/stromal cells (ASCs), dermal stem/stromal cells (DSCs) and dental pulp stem/stromal cells (DPSCs) and the heterogeneity landscape of the corresponding MSC-EVs are documented. Overall, the basic parameters, stability, and biosafety of different MSC-EVs are indiscriminate. Strikingly, UCSC-EVs exhibit distinguishing productivity. UCSC-EVs as well as DPSC-EVs present better drug loading/delivery capacity. In addition, the heterogeneity of different MSC-EVs in cargo diversity, cellular affinity, organ biodistribution, and therapeutic effects may cue the rational selection in different disease treatments. Through a combined assessment, a rational strategy is combined for selecting MSC-EVs in future clinics. Offering a panoramic view of MSC-EVs harvested from different tissues, the current study may provide guidelines for the precise selection of MSC-EVs in next-generation therapeutics.

Current Status and Prospect of Delivery Vehicle Based on Mesenchymal Stem Cell-Derived Exosomes in Liver Diseases

With the improvement of the average life expectancy and increasing incidence of obesity, the burden of liver disease is increasing. Liver disease is a serious threat to human health. Currently, liver transplantation is the only effective treatment for end-stage liver disease. However, liver transplantation still faces unavoidable difficulties. Mesenchymal stem cells (MSCs) can be used as an alternative therapy for liver disease, especially liver cirrhosis, liver failure, and liver transplantation complications. However, MSCs may have potential tumorigenic effects. Exosomes derived from MSCs (MSC-Exos), as the important intercellular communication mode of MSCs, contain various proteins, nucleic acids, and DNA. MSC-Exos can be used as a delivery system to treat liver diseases through immune regulation, apoptosis inhibition, regeneration promotion, drug delivery, and other ways. Good histocompatibility and material exchangeability make MSC-Exos a new treatment for liver diseases. This review summarizes the latest research on MSC-Exos as delivery vehicles in different liver diseases, including liver injury, liver failure, liver fibrosis, hepatocellular carcinoma (HCC), and ischemia and reperfusion injury. In addition, we discuss the advantages, disadvantages, and clinical application prospects of MSC-Exos-based delivery vectors in the treatment of liver diseases.

Mesenchymal stem cells and allergic airway inflammation; a therapeutic approach to induce immunoregulatory responses

Allergic airway inflammations are among the essential disorders worldwide that are already considered a significant concern. Mesenchymal stem cells (MSCs) are stromal cells with regenerative potential and immunomodulatory characteristics and are widely administered for tissue repair as an immunoregulatory agent in different inflammatory diseases. The current review summarized primary studies conducted to evaluate the therapeutic potential of MSCs for allergic airway disorders. In this case, modulation of airway pathologic inflammation and infiltration of inflammatory cells were examined, and modulation of the Th1/Th2 cellular balance and humoral responses. Also, the effects of MSCs on the Th17/Treg ratio and inducing Treg immunoregulatory responses along with macrophage and dendritic cell function were evaluated.

Menstrual Blood-Derived Mesenchymal Stem Cells Encapsulated in Autologous Platelet-Rich Gel Facilitate Rotator Cuff Healing in a Rabbit Model of Chronic Tears

BACKGROUND

Successful management of chronic rotator cuff (RC) tears remains a challenge owing to its limited intrinsic healing capacity and unsatisfactory failure rate. Menstrual blood-derived mesenchymal stem cells (MenSCs) have the potential to differentiate into the chondrogenic or osteogenic lineage. Autologous platelet-rich gel (APG), a gel material derived from platelet-rich plasma (PRP), can be applied as a carrier system for cell delivery and also as a releasing system for endogenous growth factors.

PURPOSE

To investigate the effect of human MenSCs encapsulated in APG (MenSCs@APG) on the healing of chronic RC tears in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

After evaluation of the effect of PRP on MenSC proliferation or differentiation, the stem cells were encapsulated in APG for in vivo injection. Supraspinatus tenotomy from the right greater tuberosity was performed on 45 New Zealand White rabbits. After 6 weeks, these rabbits were randomly allocated to 3 supplemental treatments during supraspinatus repair: saline injection (control [CTL] group), APG injection (APG group), and MenSCs@APG injection (MenSCs@APG group). At week 18, these rabbits were sacrificed to harvest the humerus-supraspinatus tendon complexes for micro-computed tomography (CT), histological evaluation, tensile test, and MenSC tracking.

RESULTS

In vitro results showed that APG can stimulate MenSC proliferation and enhance chondrogenic or osteogenic differentiation. In vivo results showed that APG can act as a carrier for delivering MenSCs into the healing site, and also as a stimulator for enhancing the in vivo performance of MenSCs. Micro-CT showed that bone volume/total volume and trabecular thickness of the new bone in the MenSCs@APG group presented significantly larger values than those of the APG or CTL group (P < .05 for all). Histologically, compared with the CTL or APG group, significantly more mature fibrocartilage regenerated at the healing site in the MenSCs@APG group. A large number of human nuclei-stained cells were observed in the MenSCs@APG group, presenting a similar appearance to fibrochondrocytes or osteocytes. Biomechanically, the MenSCs@APG group showed significantly higher failure load and stiffness than the APG or CTL group (P < .05 for all).

CONCLUSION

Human MenSCs@APG facilitated RC healing in a rabbit model of chronic tears.

CLINICAL RELEVANCE

Autogenous MenSCs@APG may be a new stem cell-based therapy for augmenting RC healing in the clinic.

Technological aspects of manufacturing and analytical control of biological nanoparticles

Extracellular vesicles (EVs) are cell-derived biological nanoparticles that gained great interest for drug delivery. EVs have numerous advantages compared to synthetic nanoparticles, such as ideal biocompatibility, safety, ability to cross biological barriers and surface modification via genetic or chemical methods. On the other hand, the translation and the study of these carriers resulted difficult, mostly because of significant issues in up-scaling, synthesis and impractical methods of quality control. However, current manufacturing advances enable EV packaging with any therapeutic cargo, including DNA, RNA (for RNA vaccines and RNA therapeutics), proteins, peptides, RNA-protein complexes (including gene-editing complexes) and small molecules drugs. To date, an array of new and upgraded technologies have been introduced, substantially improving EV production, isolation, characterization and standardization. The used-to-be "gold standards" of EV manufacturing are now outdated, and the state-of-art requires extensive revision. This review re-evaluates the pipeline for EV industrial production and provides a critical overview of the modern technologies required for their synthesis and characterization.

Combinational administration of mesenchymal stem cell-derived exosomes and metformin reduces inflammatory responses in an in vitro model of insulin resistance in HepG2 cells

Diabetes is a highly common metabolic disorder in advanced societies. One of the causes of diabetes is insulin resistance, which is associated with a loss of sensitivity to insulin-sensitive cells. Insulin resistance develops in the body of a person prone to diabetes many years before diabetes development. Insulin resistance is associated with complications such as hyperglycemia, hyperlipidemia, and compensatory hyperinsulinemia and causes liver inflammation, which, if left untreated, can lead to cirrhosis, fibrosis, and even liver cancer. Metformin is the first line of treatment for patients with diabetes, which lowers blood sugar and increases insulin sensitivity by inhibiting gluconeogenesis in liver cells. The use of metformin has side effects, including a metallic taste in the mouth, vomiting, nausea, diarrhea, and upset stomach. For this reason, other treatments, along with metformin, are being developed. Considering the anti-inflammatory role of mesenchymal stem cells (MSCs) derived exosomes, their use seems to help improve liver tissue function and prevent damage caused by inflammation. This study investigated the anti-inflammatory effect of Wharton's jelly MSCs derived exosomes in combination with metformin in the HepG2 cells insulin resistance model induced by high glucose. This study showed that MSCs derived exosomes as an anti-inflammatory agent in combination with metformin could increase the therapeutic efficacy of metformin without needing to change metformin doses by decreasing inflammatory cytokines production, including IL-1, IL-6, and TNF-α and apoptosis in HepG2 cells.

Mesenchymal Stem Cell-Derived Extracellular Vesicles: Hype or Hope for Skeletal Muscle Anti-Frailty

Steadily rising population ageing is a global demographic trend due to the advancement of new treatments and technologies in the medical field. This trend also indicates an increasing prevalence of age-associated diseases, such as loss of muscle mass (sarcopenia), which tends to afflict the older population. The deterioration in muscle function can cause severe disability and seriously affects a patient's quality of life. Currently, there is no treatment to prevent and reverse age-related skeletal muscle ageing frailty. Existing interventions mainly slow down and control the signs and symptoms. Mesenchymal stem cell-derived extracellular vesicle (MSC-EV) therapy is a promising approach to attenuate age-related skeletal muscle ageing frailty. However, more studies, especially large-scale randomised clinical trials need to be done in order to determine the adequacy of MSC-EV therapy in treating age-related skeletal muscle ageing frailty. This review compiles the present knowledge of the causes and changes regarding skeletal muscle ageing frailty and the potential of MSC-EV transplantation as a regenerative therapy for age-related skeletal muscle ageing frailty and its clinical trials.

Mesenchymal stromal/stem cell (MSC)-derived exosomes in clinical trials

Mesenchymal stromal/stem cells (MSCs) are widely utilized in cell therapy because of their robust immunomodulatory and regenerative properties. Their paracrine activity is one of the most important features that contribute to their efficacy. Recently, it has been demonstrated that the production of various factors via extracellular vesicles, especially exosomes, governs the principal efficacy of MSCs after infusion in experimental models. Compared to MSCs themselves, MSC-derived exosomes (MSC-Exos) have provided significant advantages by efficiently decreasing unfavorable adverse effects, such as infusion-related toxicities. MSC-Exos is becoming a promising cell-free therapeutic tool and an increasing number of clinical studies started to assess the therapeutic effect of MSC-Exos in different diseases. In this review, we summarized the ongoing and completed clinical studies using MSC-Exos for immunomodulation, regenerative medicine, gene delivery, and beyond. Additionally, we summarized MSC-Exos production methods utilized in these studies with an emphasis on MSCs source, MSC-Exos isolation methods, characterization, dosage, and route of administration. Lastly, we discussed the current challenges and future directions of exosome utilization in different clinical studies as a novel therapeutic strategy.

Mesenchymal Stem Cell-derived Exosomes: Novel Therapeutic Approach for Inflammatory Bowel Diseases

As double membrane-encapsulated nanovesicles (30-150 nm), exosomes (Exos) shuttle between different cells to mediate intercellular communication and transport active cargoes of paracrine factors. The anti-inflammatory and immunomodulatory activities of mesenchymal stem cell (MSC)-derived Exos (MSC-Exos) provide a rationale for novel cell-free therapies for inflammatory bowel disease (IBD). Growing evidence has shown that MSC-Exos can be a potential candidate for treating IBD. In the present review, we summarized the most critical advances in the properties of MSC-Exos, provided the research progress of MSC-Exos in treating IBD, and discussed the molecular mechanisms underlying these effects. Collectively, MSC-Exos had great potential for cell-free therapy in IBD. However, further studies are required to understand the full dimensions of the complex Exo system and how to optimize its effects.

Homogenous subpopulation of human mesenchymal stem cells and their extracellular vesicles restore function of endometrium in an experimental rat model of Asherman syndrome

BACKGROUND

Asherman syndrome (AS), or intrauterine adhesions, is a main cause of infertility in reproductive age women after endometrial injury. Mesenchymal stem cells (MSCs) and their extracellular vesicles (EVs) are promising candidates for therapies that repair damaged endometria. However, concerns about their efficacy are attributed to heterogeneity of the cell populations and EVs. A homogenous population of MSCs and effective EV subpopulation are needed to develop potentially promising therapeutic options in regenerative medicine.

METHODS

AS model was induced by mechanical injury in adult rat uteri. Then, the animals were treated immediately with homogeneous population of human bone marrow-derived clonal MSCs (cMSCs), heterogenous parental MSCs (hMSCs), or cMSCs-derived EV subpopulations (EV20K and EV110K). The animals were sacrificed two weeks post-treatment and uterine horns were collected. The sections were taken, and hematoxylin-eosin was used to examine the repair of endometrial structure. Fibrosis was measured by Masson's trichrome staining and α-SMA and cell proliferation by Ki67 immunostaining. The function of the uteri was explored by the result of mating trial test. Expression changes of TNFα, IL-10, VEGF, and LIF were assayed by ELISA.

RESULTS

Histological analysis indicated fewer glands, thinner endometria, increased fibrotic areas, and decreased proliferation of epithelial and stroma of the uteri in the treated compared with intact and sham-operated animals. However, these parameters improved after transplantation of both types of cMSCs and hMSCs and/or both cryopreserved EVs subpopulations. The cMSCs demonstrated more successful implantation of the embryos in comparison with hMSCs. The tracing of the transplanted cMSCs and EVs showed that they migrated and localized in the uteri. Protein expression analysis results demonstrated downregulation of proinflammatory factor TNFα and upregulation of anti-inflammatory cytokine IL-10, and endometrial receptivity cytokines VEGF and LIF in cMSC- and EV20K-treated animals.

CONCLUSION

Transplantation of MSCs and EVs contributed to endometrial repair and restoration of reproductive function, likely by inhibition of excessive fibrosis and inflammation, enhancement of endometrial cell proliferation, and regulation of molecular markers related to endometrial receptivity. Compared to classical hMSCs, cMSCs were more efficient than hMSCs in restoration of reproductive function. Moreover, EV20K is more cost-effective and feasible for prevention of AS in comparison with conventional EVs (EV110K).

Radiation-Induced Bystander Effect on the Genome of Bone Marrow Mesenchymal Stem Cells in Lung Cancer

Aims: Radiation by-radiation effect (RIBE) can induce the genomic instability of bone marrow mesenchymal stem cells (BMSCs) adjacent to lung cancer, and this effect not only exists in the short-term, but also accompanies it in the long-term, but its specific mechanism is not clear. Our goal is to explore the similarities and differences in the mechanism of genomic damage in tumor-associated BMSCs induced by short-term and long-term RIBE, and to provide a theoretical basis for adjuvant drugs for protection against RIBE at different clinical time periods. Results: We found that both short- and long-term RIBE induced genomic instability. We could show a high expression of TGF-β1, TNF-α, and HIF-1α in tumor-associated BMSCs after short-term RIBE whereas only TNF-α and HIF-1α expression was increased in long-term RIBE. We further confirmed that genomic instability is associated with the activation of the HIF-1α pathway and that this is mediated by TNF-α and TGF-β1. In addition, we found differences in the mechanisms of genomic instability in the considered RIBE windows of analysis. In short-term RIBE, both TNF-α and TGF-β1 play a role, whereas only TNF-α plays a decisive role in long-term RIBE. In addition, there were differences in BMSC recruitment and genomic instability of different tissues with a more pronounced expression in tumor and bone marrow than compared to lung. Innovation and Conclusion: We could show dynamic changes in the expression of the cytokines TGF-β1 and TNF-α during short- and long-term RIBE. The differential expression of the two is the key to causing the genomic damage of tumor-associated BMSCs in the considered windows of analysis. Therefore, these results may serve as a guideline for the administration of radiation protection adjuvant drugs at different clinical stages. Antioxid. Redox Signal. 38, 747-767.

Stem cell-derived exosomes in bone healing: focusing on their role in angiogenesis

Fractures in bone, a tissue critical in protecting other organs, affect patients' quality of life and have a heavy economic burden on societies. Based on regenerative medicine and bone tissue engineering approaches, stem cells have become a promising and attractive strategy for repairing bone fractures via differentiation into bone-forming cells and production of favorable mediators. Recent evidence suggests that stem cell-derived exosomes could mediate the therapeutic effects of their counterpart cells and provide a cell-free therapeutic strategy in bone repair. Since bone is a highly vascularized tissue, coupling angiogenesis and osteogenesis is critical in bone fracture healing; thus, developing therapeutic strategies to promote angiogenesis will facilitate bone regeneration and healing. To this end, stem cell-derived exosomes with angiogenic potency have been developed to improve fracture healing. This review summarizes the effects of stem cell-derived exosomes on the repair of bone tissue, focusing on the angiogenesis process.

An update on renal fibrosis: from mechanisms to therapeutic strategies with a focus on extracellular vesicles

The increasing prevalence of chronic kidney disease (CKD) is a major global public health concern. Despite the complicated pathogenesis of CKD, renal fibrosis represents the most common pathological condition, comprised of progressive accumulation of extracellular matrix in the diseased kidney. Over the last several decades, tremendous progress in understanding the mechanism of renal fibrosis has been achieved, and corresponding potential therapeutic strategies targeting fibrosis-related signaling pathways are emerging. Importantly, extracellular vesicles (EVs) contribute significantly to renal inflammation and fibrosis by mediating cellular communication. Increasing evidence suggests the potential of EV-based therapy in renal inflammation and fibrosis, which may represent a future direction for CKD therapy.

Docosahexaenoic acid-loaded chitosan/alginate membrane reduces biofilm formation by P. aeruginosa and promotes MSC-mediated burn wound healing

Aims: Chitosan, like docosahexaenoic acid (DHA) and mesenchymal stem cells (MSCs), is used in medicine as a wound healing accelerator. Thus, in this study, chitosan-alginate (CA) membranes containing DHA and MSCs were produced, and their antibacterial and antibiofilm activities against burn infections caused by Pseudomonas aeruginosa were investigated.Methods: Physicochemical properties were assessed by SEM, Fourier transform infrared (FTIR), and X-ray diffraction (XRD). Porosity, cytocompatibility, and antibacterial and antibiofilm activities were evaluated both in vitro and in vivo. The viability and apoptosis of MSCs were studied using flow cytometry. Wound healing effects were analyzed based on histopathological features, the wound contraction rate (WCR) ratio, and bacterial clearance.Results: The CA membranes showed antibiofilm activity both in vivo and in vitro, accompanied by reduced lasI and rhlI expressions and pyocyanin production. The membranes were highly porous and biocompatible and showed favorable physicochemical properties. Docosahexaenoic acid incorporation to CA membranes improved their antibacterial and antibiofilm activities, as well as MSCs' viability by reducing crystallinity and increasing porosity (p = .008). Treatment with CA-DHA-MSC accelerated burn wound healing (with complete healing being observed after 14 days, WCR = 85%) and augmented antibacterial and antibiofilm activities in vivo compared to CA-DHA and CA-MSC. The CA-DHA-MSC group delivered a significantly higher WCR and lower inflammation than the CA-MSC group (p = .0001).Conclusion: In combination with DHA-loaded CA membranes, MSCs reduced the healing time of burn wounds, offering a viable option for designing effective wound dressings.

Exosomes for angiogenesis induction in ischemic disorders

Ischaemic disorders are leading causes of morbidity and mortality worldwide. While the current therapeutic approaches have improved life expectancy and quality of life, they are unable to "cure" ischemic diseases and instate regeneration of damaged tissues. Exosomes are a class of extracellular vesicles with an average size of 100-150 nm, secreted by many cell types and considered a potent factor of cells for paracrine effects. Since exosomes contain multiple bioactive components such as growth factors, molecular intermediates of different intracellular pathways, microRNAs and nucleic acids, they are considered as cell-free therapeutics. Besides, exosomes do not rise cell therapy concerns such as teratoma formation, alloreactivity and thrombotic events. In addition, exosomes are stored and utilized more convenient. Interestingly, exosomes could be an ideal complementary therapeutic tool for ischemic disorders. In this review, we discussed therapeutic functions of exosomes in ischemic disorders including angiogenesis induction through various mechanisms with specific attention to vascular endothelial growth factor pathway. Furthermore, different delivery routes of exosomes and different modification strategies including cell preconditioning, gene modification and bioconjugation, were highlighted. Finally, pre-clinical and clinical investigations in which exosomes were used were discussed.

Exosomes derived from mesenchymal stem cells: Heralding a new treatment for periodontitis?

Periodontitis, as a complex inflammatory disorder, is characterized by continuous destruction of the teeth-supporting components, like alveolar bone and periodontal ligament, and affects a great percentage of individuals over the world. Also, this oral disease is linked with multiple serious illnesses, e.g., cardiovascular disorders, diabetes, and oral cancer; thus, exerting efficient therapy for periodontitis is necessary. Unfortunately, the current therapies for the disease (e.g., surgical and nonsurgical methods) have not reflected enough effectiveness against periodontitis. At present, mesenchymal stem cell (MSC)-based remedy has created new hope for curating different diseases; however, MSCs have no capability to engraft into the chosen tissue, and the tumorigenic influences of MSCs are still the main concern. Interestingly, documents have revealed that MSC-derived mediators, like exosomes, which their exploitation is more feasible than intact MSCs, can be an effective therapeutic candidate for periodontitis. Therefore, in this study, we will review evidence in conjunction with their possible curative impacts on periodontitis cases.

Biochemistry of exosomes and their theranostic potential in human diseases

Exosomes are classified as special extracellular vesicles in the eukaryotic system having diameters ranging from 30 to 120 nm. These vesicles carry various endogenous molecules including DNA, mRNA, microRNA, circular RNA, and proteins, crucial for numerous metabolic reactions and can be proposed as therapeutic or diagnostic targets for several disorders. The donor exosomes release their content to recipient cells and further establish the significant intercellular communication showing biological effects by triggering environmental alterations. Exosomes derived from mesenchymal and dendritic cells have demonstrated their therapeutic potential against organ injury. Yet, various intricacies are involved in exosomal transport and its inclusion in cancer and other disease pathogenesis needs to be explored. The exosomes represent profound potential as diagnostic biomarkers and therapeutic carriers in various pathophysiological conditions such as neurodegenerative diseases, chronic cancers, infectious diseases, female reproductive diseases and cardiovascular diseases. In the current study, we demonstrate the advancements in the implication of exosomes as one of the irrefutable prognostic biological targets in human health and diseases.

Mechanisms and clinical application potential of mesenchymal stem cells-derived extracellular vesicles in periodontal regeneration

Periodontitis is a high prevalence oral disease which damages both the hard and soft tissue of the periodontium, resulting in tooth mobility and even loss. Existing clinical treatment methods cannot fully achieve periodontal tissue regeneration; thus, due to the unique characteristics of mesenchymal stem cells (MSCs), they have become the focus of attention and may be the most promising new therapy for periodontitis. Accumulating evidence supports the view that the role of MSCs in regenerative medicine is mainly achieved by the paracrine pathway rather than direct proliferation and differentiation at the injured site. Various cells release lipid-enclosed particles known as extracellular vesicles (EVs), which are rich in bioactive substances. In periodontitis, EVs play a pivotal role in regulating the biological functions of both periodontal tissue cells and immune cells, as well as the local microenvironment, thereby promoting periodontal injury repair and tissue regeneration. As a cell-free therapy, MSCs-derived extracellular vesicles (MSC-EVs) have some preponderance on stability, immune rejection, ethical supervision, and other problems; therefore, they may have a broad clinical application prospect. Herein, we gave a brief introduction to MSC-EVs and focused on their mechanisms and clinical application in periodontal regeneration.

Mesenchymal Stromal Cell-Based Targeted Therapy Pancreatic Cancer: Progress and Challenges

Pancreatic cancer is an aggressive malignancy with high mortality rates and poor prognoses. Despite rapid progress in the diagnosis and treatment of pancreatic cancer, the efficacy of current therapeutic strategies remains limited. Hence, better alternative therapeutic options for treating pancreatic cancer need to be urgently explored. Mesenchymal stromal cells (MSCs) have recently received much attention as a potential therapy for pancreatic cancer owing to their tumor-homing properties. However, the specific antitumor effect of MSCs is still controversial. To this end, we aimed to focus on the potential anti-cancer treatment prospects of the MSC-based approach and summarize current challenges in the clinical application of MSCs to treat pancreatic cancer.

Adipose stem cells-derived exosomes modified gelatin sponge promotes bone regeneration

Background: Large bone defects resulting from trauma and diseases still a great challenge for the surgeons. Exosomes modified tissue engineering scaffolds are one of the promising cell-free approach for repairing the defects. Despite extensive knowledge of the variety kinds of exosomes promote tissue regeneration, little is known of the effect and mechanism for the adipose stem cells-derived exosomes (ADSCs-Exos) on bone defect repair. This study aimed to explore whether ADSCs-Exos and ADSCs-Exos modified tissue engineering scaffold promotes bone defects repair. Material/Methods: ADSCs-Exos were isolated and identified by transmission electron microscopy nanoparticle tracking analysis, and western blot. Rat bone marrow mesenchymal stem cells (BMSCs) were exposed to ADSCs-Exos. The CCK-8 assay, scratch wound assay, alkaline phosphatase activity assay, and alizarin red staining were used to evaluate the proliferation, migration, and osteogenic differentiation of BMSCs. Subsequently, a bio-scaffold, ADSCs-Exos modified gelatin sponge/polydopamine scaffold (GS-PDA-Exos), were prepared. After characterized by scanning electron microscopy and exosomes release assay, the repair effect of the GS-PDA-Exos scaffold on BMSCs and bone defects was evaluated in vitro and in vivo. Results: The diameter of ADSCs-exos is around 122.1 nm and high expressed exosome-specific markers CD9 and CD63. ADSCs-Exos promote the proliferation migration and osteogenic differentiation of BMSCs. ADSCs-Exos was combined with gelatin sponge by polydopamine (PDA)coating and released slowly. After exposed to the GS-PDA-Exos scaffold, BMSCs have more calcium nodules with osteoinductive medium and higher expression the mRNA of osteogenic related genes compared with other groups. The quantitative analysis of all micro-CT parameters showed that GS-PDA-Exos scaffold promote new bone formed in the femur defect model in vivo and confirmed by histological analysis. Conclusion: This study demonstrates the repair efficacy of ADSCs-Exos in bone defects, ADSCs-Exos modified scaffold showing a huge potential in the treatment of large bone defects.

Exosome-Functionalized, Drug-Laden Bone Substitute along with an Antioxidant Herbal Membrane for Bone and Periosteum Regeneration in Bone Sarcoma

Developing advanced methods for effective bone reconstructive strategies in case of critical bone defects caused by tumor resection, trauma, and other implant-related complications remains a challenging problem in orthopedics. In the clinical management of bone diseases, there is a paradigm shift in using local drugs at the injury site; however, the dead space created during the surgical debridement of necrotic bone and soft tissues (periosteum and underlying muscle) leads to ineffective bone formation, thereby leading to secondary complications, and thus calls for better regenerative approaches. In this study, we have utilized an exosome-functionalized doxorubicin-loaded biodegradable nanocement (NC)-based carrier along with a Cissus quadrangularis (CQ) extract-laden antioxidant herbal membrane for simultaneously managing the periosteum as well as bone formation in the tumor resection model of osteosarcoma. We initially evaluated the efficacy of scaffolds for in vitro mineralization and bone formation. To examine the in vivo effectiveness, we developed a human osteosarcoma cell line (Saos-2)-induced tumor xenograft model with a critical-sized bone defect. The findings revealed that doxorubicin released from NC was successful in killing the tumor cells and was present even after 30 days of implantation. Additionally, the incorporation of exosomes aided the bone formation, resulting in around a 2.6-fold increase in the bone volume compared to the empty group as evaluated by micro-CT. The herbal membrane assisted in the development of periosteum and mineralizing bone callous as validated through histological and immunofluorescence analysis. Thus, our findings describe a one-step biomaterial-based cell-free approach to regenerate bone in osteosarcoma and prevent further fracture due to the complete development of periosteum and lost bone.