The widespread use of human mesenchymal stem cells(hMSCs) is impeded by functional loss during prolonged expansion. Although multiple approaches have been attempted to preserve hMSCs stemness, a suitable culture system remains to be modified. The interaction between electrical signals and stem cells is expected to better maintain the function of stem cells. However, it remains unclear whether the surface potential of substrates has the potential to preserve stem cell function during in vitro expansion. In our study, hMSCs cultured on materials with different surface potentials could be induced into a reversible quiescent state, and we demonstrated that quiescent hMSCs could be reactivated and transitioned back into the proliferation cell cycle. hMSCs cultured under appropriate potential displayed superior differentiation and proliferation abilities within the same generation compared to conventional conditions. These findings underscore the importance of surface potential as a critical physical factor regulating hMSCs stemness. Manipulating the surface potential of hMSCs culture substrates holds promise for optimising preservation and culture conditions, thereby enhancing their application in tissue repair and regeneration engineering.

This Review explores the growing and diversifying field of tissue-derived abiotic constructs for tissue engineering applications, with main focus on decellularization and devitalization techniques and principles. Acellular fractions derived from biological tissues, such as the extracellular matrix (ECM), have long been considered a valuable approach for the generation of numerous scaffolds and more complex constructs. The removal of the cellular content has been considered essential to prevent the development of adverse immunological reactions. Nevertheless, the discovery of promising features of certain cellular components has sparked interest in the use of inactivated or devitalized cellular fractions for several applications, particularly in regenerative medicine and inflammation control. Devitalization has been described for several clinical applications, but remains poorly explored in terms of in vitro constructs compared to decellularization methods currently available. In this review, we present and critically evaluate a spectrum of approaches for the decellularization of whole-organs and in vitro constructs, and the most prevalent devitalization techniques, with a discussion on their implications on scaffolds composition, structure, and potentially therapeutic properties. Processing methodologies to achieve optimal cell-based abiotic materials and approaches for their effective characterization are described and discussed. The application of these materials in healthcare, with most focus on regenerative approaches and including examples of commercially available products, is also addressed.

Allogeneic cells represent promising intelligent delivery platforms owing to their intrinsic target homing ability, ready-to-use, scalability and broad applicability. However, implanted allogeneic cells are susceptible to rapid clearance by mononuclear phagocytic system (MPS), resulting in short half-life and compromised therapeutic efficacy. To overcome this limitation, we constructed genetically engineered allogeneic cells with surface-expressed CD24, a "don't eat me" signal protein, to evade phagocytosis by macrophages. Additionally, we modified the allogeneic cells with azide groups, creating a binding site for dibenzocyclooctyne (DBCO)-modified drugs through copper-free click chemistry. The results showed that mesenchymal stem cells (MSCs) have natural inflammation-targeting properties, and modification of allogeneic MSCs (M24N3 cells) significantly prolonged their retention at the site of inflammation. Moreover, DBCO-modified antimicrobial peptides (DBCO-LL37) were more effectively recruited to inflammation sites via bioorthogonal reactions, resulting in sustained bacterial clearance. The M24N3@DBCO-LL37 treatment cleared multiple sepsis mediators, extended circulation time, and increased tissue retention, ultimately protecting against organ damage and delaying sepsis-induced lethality, subsequently resulting in remarkable survival rate elevation. These findings underscore the potential of bioorthogonal system based on engineered allogeneic cells for the treatment of complex inflammatory diseases, highlighting their promising applications in evading rapid clearance systems in vivo. STATEMENT OF SIGNIFICANCE: In recent years, allogeneic cells have garnered significant research interest as emerging drug delivery carriers due to their off-the-shelf availability, scalable production, and broad therapeutic applicability. However, recognition and elimination mediated by the mononuclear phagocyte system (MPS) brings a substantial challenge to their clinical application. We developed an engineered bioorthogonal cell delivery system, M24N3@DBCO-LL37, through genetic engineering and glucose metabolic engineering methods, which could avoid phagocytosis of allogeneic cells by macrophages, prolong the retention time of allogeneic cells at the site of inflammation, recruit more DBCO-modified antimicrobial peptides (DBCO-LL37), and significantly reduced the mortality rate and improved therapeutic efficiency in a mouse model of sepsis. This strategy can not only be used in the development of cell delivery systems, but also has the potential to be used in the design of more allogeneic cell therapy strategies, such as chimeric antigen receptor T-cell immunotherapy (CAR-T), haematopoietic stem cell transplantation and organ transplantation, to improve the therapeutic efficacy.

In regenerative medicine, mesenchymal stem cells (MSCs) constitute a promising therapeutic route for many diseases. The current quality-by-design guidelines do not clearly define a framework for MSC production. Here, we suggest and experimentally validate a model-based method to determine design spaces (DSs) for MSC cultivation. A kinetic model used in previous work was employed; part of the experimental data was used to re-estimate the maximum specific growth rate in the kinetic model and then calculate the prediction intervals of this parameter. Subsequently, regions of seeding density and harvesting time where both the upper and lower limits of growth predictions met the acceptable number of cells and confluency with given risk levels were defined as DSs. Finally, the established DS was validated with the remaining data; it allowed better predictions of the cell numbers and confluency under specific cultivation conditions and improved the overall robustness of MSC cultivation processes.

Stem cell functions and ageing are deeply interconnected, continually influencing each other in multiple ways. Stem cells play a vital role in organ maintenance, regeneration, and homeostasis, all of which decline over time due to gradual reduction in their self-renewal, differentiation, and growth factor secretion potential. The functional decline is attributed to damaging extrinsic environmental factors and progressively worsening intrinsic genetic and biochemical processes. These ageing-associated deteriorative changes have been extensively documented, paving the way for the discovery of novel biomarkers of ageing for detection, diagnosis, and treatment of age-related diseases. Age-dependent changes in adult stem cells include numerical decline, loss of heterogeneity, and reduced self-renewal and differentiation, leading to a drastic reduction in regenerative potential and thereby driving the ageing process. Conversely, ageing also adversely alters the stem cell niche, disrupting the molecular pathways underlying stem cell homing, self-renewal, differentiation, and growth factor secretion, all of which are critical for tissue repair and regeneration. A holistic understanding of these molecular mechanisms, through empirical research and clinical trials, is essential for designing targeted therapies to modulate ageing and improve health parameters in older individuals.

From the pioneering days of cell therapy to the achievement of bioprinting organs, tissue engineering, and regenerative medicine have seen tremendous technological advancements, offering solutions for restoring damaged tissues and organs. However, only a few products and technologies have received United States Food and Drug Administration approval. This review highlights significant progress in cell therapy, extracellular vesicle-based therapy, and tissue engineering. Hematopoietic stem cell transplantation is a powerful tool for treating many diseases, especially hematological malignancies. Mesenchymal stem cells have been extensively studied. The discovery of induced pluripotent stem cells has revolutionized disease modeling and regenerative applications, paving the way for personalized medicine. Gene therapy represents an innovative approach to the treatment of genetic disorders. Additionally, extracellular vesicle-based therapies have emerged as rising stars, offering promising solutions in diagnostics, cell-free therapeutics, drug delivery, and targeted therapy. Advances in tissue engineering enable complex tissue constructs, further transforming the field. Despite these advancements, many technical, ethical, and regulatory challenges remain. This review addresses the current bottlenecks, emphasizing novel technologies and interdisciplinary research to overcome these hurdles. Standardizing practices and conducting clinical trials will balance innovation and regulation, improving patient outcomes and quality of life.

Mesenchymal-stromal-cell-derived extracellular vesicles (MSC-EVs) play a key role in the paracrine effects of MSC and have demonstrated therapeutic potential in various preclinical models. However, clinical translation is hindered by manufacturing practices relying on planar culture systems, fetal bovine serum (FBS)-supplemented media, and non-scalable, low-purity EV isolation methods that fail to meet dose and safety requirements, underscoring the need for innovative approaches. In this study, we developed a scalable platform to manufacture human MSC-EVs at clinically relevant numbers, integrating continuous collection of EV-enriched conditioned media (CM) using a stirred-tank reactor (STR) under xenogeneic-free conditions and a scalable downstream process.

Wharton's jelly-derived MSC (MSC(WJ)) were expanded using microcarriers in a controlled STR using human platelet lysate (hPL)-supplemented medium. Then, a 3-day EV production stage, featuring continuous harvesting of the CM, was established using a novel serum-/xeno(geneic)-free exosome depleted-hPL supplement. For the isolation of MSC-EVs, a scalable process was implemented by pairing tangential flow filtration and anion exchange chromatography. Isolated MSC-EVs were characterised using nanoparticle tracking analysis, protein and zeta potential quantification, western blot analysis of EV protein markers, transmission electron microscopy and uptake studies of fluorescently labelled-EVs.

The system sustained the efficient expansion of MSC(WJ), reaching a total of (6.03 ± 0.181) x 107 cells after 7 days, which corresponds to a 30.1 ± 0.740-fold expansion. Upon a 3-day continuous CM harvesting, a total of (2.13 ± 0.301) x 1012 EVs were isolated corresponding to a particle yield factor of (1.26 ± 0.186) x 104 EVs/cell/day. MSC-EVs presented high purity levels ((5.53 ± 1.55) x 109 particles/µg), a homogeneous small size distribution (mean diameter of 115 ± 4.88 nm), a surface charge of -23.4 ± 6.23 mV, positive detection of tetraspanins CD9 and CD63 and syntenin-1 and displayed a typical cup-shaped morphology. MSC-EVs were readily incorporated by endothelial cells and two human breast cancer cell lines.

Overall, the scalable and Good Manufacturing Practices (GMP)-compliant platform established herein enabled the reproducible manufacturing of MSC-EVs with high purity and generally accepted characteristics concerning size, protein markers, surface charge, morphology, and cellular internalization, validating its potential for future clinical applications.

Autoimmune hepatitis (AIH) is an immune-mediated disease for which there is no effective treatment. Mesenchymal stromal cells (MSCs) have become a promising treatment, but low AIH treatment efficacy has hampered the clinical application of MSCs.

By using Good Manufacturing Practices, we generated mesenchymal stromal cells with enhanced immunomodulation by over-expressing PD-L1 and ICAM1 (PI-MSCs). PI-MSCs biological characteristics were established, a tertiary cell bank created, and safety of PI-MSCs determined. Finally, the efficacy of PI-MSCs for treatment of AIH was evaluated.

PI-MSCs preserved MSCs identity, with a normal karyotype, stable genome, and no tumorigenicity. The long-term safe dose was up to 5.0 × 107 cells/kg. PI-MSCs showed better therapeutic effect than conventional MSCs for treating AIH in a mouse model. Notably, PI-MSCs showed better homing to injured liver tissue than conventional MSCs. Furthermore, PI-MSCs treatment significantly increased Treg cells in the blood and spleen of AIH model mice compared to conventional MSCs.

PD-L1 and ICAM1 empower MSCs immuno-regulation, these empowered MSCs are more effective treatment for AIH. These findings provide support for the translation of PI-MSCs to the clinic for treatment of AIH patients.

Neurodegenerative diseases including Alzheimer's and Parkinson's disease are age-related disorders which severely impact quality of life and impose significant societal burdens. Cellular senescence is a critical factor in these disorders, contributing to their onset and progression by promoting permanent cell cycle arrest and reducing cellular function, affecting various types of cells in brain. Recent advancements in regenerative medicine have highlighted "R3" strategies-rejuvenation, regeneration, and replacement-as promising therapeutic approaches for neurodegeneration. This review aims to critically analyze the role of cellular senescence in neurodegenerative diseases and organizes therapeutic approaches within the R3 regenerative medicine paradigm. Specifically, we examine stem cell therapy, direct lineage reprogramming, and partial reprogramming in the context of R3, emphasizing how these interventions mitigate cellular senescence and counteracting aging-related neurodegeneration. Ultimately, this review seeks to provide insights into the complex interplay between cellular senescence and neurodegeneration while highlighting the promise of cell-based regenerative strategies to address these debilitating conditions.

The local delivery of mesenchymal stem cell-derived extracellular vesicles (EVs) via hydrogel has emerged as an effective approach for spinal cord injury (SCI) treatment. However, achieving on-demand release of EVs from hydrogel to address dynamically changing pathology remains challenging. Here, we used a series of engineering methods to further enhance EVs' efficacy and optimize their release pattern from hydrogel. Specifically, the pro-angiogenic, neurotrophic, and anti-inflammatory effects of EVs were reinforced through three-dimensional culture and dexamethasone (Dxm) encapsulation. Then, the prepared Dxm-loaded 3EVs (3EVs-Dxm) were membrane modified with ortho-dihydroxy groups (-2OH) and formed an EV-integrated hydrogel (3EVs-Dxm-Gel) via the cross-link with phenylboronic acid-modified hyaluronic acid and tannic acid. The phenylboronic acid ester in 3EVs-Dxm-Gel enabled effective immobilization and reactive oxygen species-responsive release of EVs. Topical injection of 3EVs-Dxm-Gel in SCI rats notably mitigated injury severity and promoted functional recovery, which may offer opportunities for EV-based therapeutics in central nervous system injury.

Periodontitis, the main cause of tooth loss in adults, is a public health concern; its incidence increases with age, and its prevalence increases with increasing life expectancy of the population. Innovative therapies such as cell therapy represent promising future solutions for guided tissue regeneration. However, these therapies may be associated with fears and mistrust from the general public. The aim of this study was to estimate the acceptability of an advanced therapy medicinal product combining allogeneic mesenchymal stromal cells from adipose tissue with a natural fibrin hydrogel in the treatment of periodontitis.

The methodology was based on a qualitative study conducted through semi-structured interviews with patients followed for periodontitis in the Oral Medicine Department of the Toulouse University Hospital, Toulouse, France. Qualitative studies are essential methodologies to understand the patterns of health behaviours, describe illness experiences, and design health interventions in a humanistic and person-centred way of discovering.

Eleven interviews (with 4 men and 7 women) were required to reach thematic saturation. Analysis allowed 4 main themes to emerge: (1) perception of new treatments, science, and caregivers; (2) conditions that the treatment must meet; (3) patient perception of the disease; and (4) factors related to the content of the treatment.

Patients find cell therapy for periodontitis to be acceptable. If they express a need to be informed about the benefit/risk ratio, they are not particularly worried about side effects of the treatment, for either allogeneic or blood-derived products. Periodontitis is a prototypical model of chronic inflammatory pathology and is multitissular, with hard- and soft-tissue lesions. In a patient-centred approach, the success of cell therapy will require a bilateral, informed decision, taking into account potential therapeutic effectiveness and patient expectations for regeneration.

Mesenchymal stromal cells (MSCs) exert broad therapeutic effects across a range of inflammatory diseases. Their mechanism of action has largely been attributed to paracrine signalling, orchestrated by an array of factors produced by MSCs that are collectively termed the "secretome". Strategies to enhance the release of these soluble factors by pre-exposure to inflammatory cytokines, a concept known as "licensing", is thought to provide a means of enhancing MSC efficacy. Yet, recent evidence shows that intravenously infused MSCs entrapped within the lungs undergo apoptosis, and their subsequent clearance by host phagocytes is essential for their therapeutic efficacy. We therefore sought to clarify the mechanisms governing regulated cell death in MSCs and how exposure to inflammatory cytokines impacts this process. Our results show that MSCs are relatively resistant to cell death induced via the extrinsic pathway of apoptosis, as well as stimuli that induce necroptosis, a form of regulated inflammatory cell death. Instead, efficient killing of MSCs required triggering of the mitochondrial pathway of apoptosis, via inhibition of the pro-survival proteins MCL-1 and BCL-XL. Apoptotic bodies were readily released by MSCs during cell disassembly, a process that was inhibited in vitro and in vivo when the apoptotic effectors BAK and BAX were genetically deleted. Licensing of MSCs by pre-exposure to the inflammatory cytokines TNF and IFN-γ increased the sensitivity of MSCs to intrinsic apoptosis in vitro and accelerated their in vivo clearance by host cells within the lungs after intravenous infusion. Taken together, our study demonstrates that inflammatory "licensing" of MSCs facilitates cell death by increasing their sensitivity to triggers of the intrinsic pathway of apoptosis and accelerating the kinetics of apoptotic cell disassembly.

Mesenchymal stromal cell (MSC) therapy holds great promise for treating myocardial infarction (MI). However, the inflammatory and reactive oxygen species (ROS)-rich environment in infarcted myocardium challenges MSC survival, limiting its therapeutic impact. In this study, we demonstrate that chemical modification of MSCs with anti-VCAM1 and polydopamine (PD) significantly enhances MSC survival and promotes cardiac repair. Anti-VCAM1 modification facilitates MSC adhesion to inflamed tissue, ensuring MSC retention in the injured myocardium, while PD scavenges ROS surrounding MSCs, creating a conducive environment for cell transplantation. Our data indicate that chemically engineered MSCs effectively disrupt the inflammation-ROS cycle and modulate inflammation-related immune responses, thus improving MI microenvironments. Single-cell RNA sequencing of rat hearts reveals that treatment with engineered MSCs inhibits cardiac fibrosis by suppressing HB-EGF-EGFR signaling between anti-inflammatory macrophages and activated fibrillates. Ultimately, engineered MSCs demonstrate superior therapeutic efficacy in a rat model of MI. This study presents a straightforward, safe, and efficient chemical method for enhancing MSC therapy.

Current myocardial infarction (MI) treatment strategies remain challenged in suboptimal pharmacokinetics and potential adverse effects. Here we present a bioelectronic interface capable of producing on-demand abundant bioactive extracellular vesicles (EVs) near the MI area for in-situ localized treatment. The technology, termed electroactive patch for wirelessly and controllable EV generation (ePOWER), leverages wireless bioelectronic patch to stimulate embedded electrosensitive macrophages, actively modulating the biosynthesis of EVs and enabling EV production with high programmability to be delivered directly to the MI area. ~2400% more bioactive EVs were produced per cell under our ePOWER system. When surgically implanted, we demonstrate the therapeutic potential of in-situ EV production system to alleviate MI symptoms and improve cardiac function. This programmable ePOWER technology enables in-situ production of therapeutically rich EVs, thus reducing the need for exogenous cell expansion platforms and dedicated delivery, holding promise as a therapeutic all-in-one platform to treat various diseases.

Mesangiogenic progenitor cells (MPCs) are mesengenic and vasculogenic cells isolated from human bone marrow mononuclear cell cultures. Although MPCs were first described over two decades ago and have demonstrated promising differentiation capabilities, these cells did not attract sufficient attention from experts in the field of tissue regeneration. Several reports from the first decade of the 2000s showed MPC-like cells co-isolated in primary mesenchymal stromal cell (MSC) cultures, applying human serum. However, in most cases, these rounded and firmly attached cells were described as "contaminating" cells of hemopoietic origin. Indeed, MPC morphology, phenotype, and functional features evoke but do not completely overlap with those of cultured peripheral macrophages, and their hemopoietic origin should not be excluded. The plasticity of cells from the monocyte lineage is surprising but not completely unprecedented. Underestimated data demonstrated that circulating monocyte/macrophages could acquire broader plasticity under specific and different culture conditions, and this plasticity could be a consequence of in vitro de-differentiation. The evidence discussed here suggests that MPCs could represent the cell identity toward which the de-differentiation process reprograms the circulating mature phagocytic compartment.

Myocardial infarction (MI) with resulting congestive heart failure is one of the leading causes of death worldwide. Current therapies for treating MI, such as devices, traditional medicine, and surgeries, come with many limitations as patients in their final stages of heart failure have little chances of experiencing any reversible changes. In recent decades, Mesenchymal stem cell (MSC) based therapy has become one of the most popular and rapidly developing fields in treating MI. Their supremacy for clinical applications is partially due to their unique properties and encouraging pre-clinical outcomes in various animal disease models. However, the majority of clinical trials registered for MSC therapy for diverse human diseases, including MI, have fallen short of expectations. This review intends to discuss the recent advances in the clinical application of using MSCs for cardiac repair and discuss challenges facing the clinical translation of MSCs for cardiac regeneration such as restoration of endothelial-cardiomyocyte crosstalk, immunomodulation and immune rejection, poor homing and migration, as well as low retention and survival. Furthermore, we will discuss recent strategies being investigated to help overcome some of these challenges.

In recent years, the landscape of hematology has undergone rapid transformation, driven by innovative therapeutic strategies harnessing the properties of novel cellular therapies. Mesenchymal stem cells (MSCs) represent one of these promising therapies, with potential applications across a range of hematologic conditions. These cells are notable for their immunomodulatory properties, key role in supporting the hematopoietic micro-environment and capacity for multi-directional differentiation. This review will focus on the biologic mechanisms underlying MSC therapeutic use, current avenues of clinical investigation, and potential challenges and future directions for MSC derived therapies.

As the population ages, musculoskeletal diseases (MSK) have emerged as a significant burden for individuals, healthcare systems, and social care systems. Recently, regenerative medicine has exhibited vast potential in age-related MSK, with mesenchymal stromal cells (MSCs) and their derived exosomes (Exos) therapies showing distinct advantages. However, these therapies face several limitations, including issues related to ensuring stability and effective distribution within the body. Hydrogels, acting as an ideal carrier, can enhance the therapeutic effects and application range of MSCs and Exos derived from MSCs (MSC-Exos). Therefore, this review comprehensively summarizes the application progress of MSCs and MSC-Exos combined with hydrogels in age-related MSK disease research. It aims to provide a detailed perspective, showcasing the functional enhancement of MSCs and MSC-Exos when incorporated into hydrogels. Additionally, this review explores their potential and challenges in treating age-related MSK diseases, offering references for future research directions and potential innovative strategies.

Intrauterine adhesions (IUAs) represent a considerable impediment to female reproductive health. Despite ongoing debate regarding the optimally efficacious route of administration and dosage of stem cells for IUA treatment, human umbilical cord-derived mesenchymal stem cells (UCMSCs) have emerged as a promising avenue for regenerative therapy. The present study aimed to investigate the potential effects of UCMSCs on IUAs and to further explore the most effective treatment route and dosages. In the present study, the therapeutic potential of UCMSCs in a constructed rat model of IUAs was evaluated. The efficacy of UCMSC administration through three different routes, namely intraperitoneal injection, in-site injection and caudal vein injection, was compared at three different doses of cells (0.5x106, 1x106 and 5x106). The assessment parameters included endometrial thickness, glandular density and extent of fibrotic tissue, which were measured using HE staining and Masson staining and numbers of offspring. The IUA model group compared with the control group endometrial thickness decreased, glandular density decreased and the extent of fibrotic tissue increased, suggesting the IUA rat model had been successfully established. At 4 weeks post-treatment, an intraperitoneal injection of 1x106 UCMSCs (the middle dose) was found to have led to a significant increase in endometrial thickness and glandular count, approaching the levels that were observed in the normal group. This dosage also notably reduced the level of fibrosis compared with that in both the higher and the lower doses, although this remained slightly higher compared with that observed in the normal group. Furthermore, the reproductive capability of the rats in the higher and middle dosage IUA rat model exhibited partial recovery post-treatment. In conclusion, the results of the present study suggest that the intraperitoneal administration of 1x106 UCMSCs can provide a viable strategy for promoting endometrial regeneration and reducing fibrosis in IUA. In addition, this highlights the potential of UCMSC therapy as a means of clinical intervention for severe IUA, ultimately improving fertility outcomes, especially with regard to the specific dosage and intraperitoneal injection method.

Mesenchymal stem cell (MSC) therapy holds promise in biomedical applications but faces challenges in efficient transfection without compromising cell viability. Here, we show a serum-tolerant MSC transfection nanotool, APOs@BP, composed of an apolipoprotein (APO) corona and a boronated polyethyleneimine (BP) core. The APOs corona's serum-protein resistance and cytomembrane affinity enable APOs@BP to achieve 10.4-fold higher transfection efficiency and improved cytocompatibility in serum-containing medium compared to high-molecular-weight polycationic transfectants. For MSC neural differentiation, miRNA-124 and all-trans retinoic acid derivative (atRAN) are further loaded into APOs@BP, forming a polymeric complex for sequential drug release triggered by lysosomal acid and cytosolic reactive oxygen species post-transplantation. Transcriptomic analysis confirms that this system enhances MSC neural differentiation through sequential activation of atRAN-induced differentiation potential and miRNA-124-directed neurogenesis via cGMP-PKG, MAPK, and PI3K-Akt pathways. Transplantation of engineered MSCs reconstructs neural circuits and alleviates cognitive impairment in Alzheimer's disease model mice. Collectively, this system provides a robust and convenient method for MSC-based regenerative medicine.

Mesenchymal stem cell (MSC) therapy has emerged as a promising alternative approach for treating acute liver failure (ALF) while confronting the shortage of low efficiency and poor engraftment within a hostile liver milieu. In this study, we establish a bioactive decellularized extracellular matrix (dECM) platform that incorporates dihydrolipoic acid (DHLA)-protected Pt nanoclusters doped with Cu (PtCu-DHLA) nanozymes and cell-laden microgels. The PtCu-DHLA nanozymes, selected for their versatility, function as antioxidant, anti-inflammatory, pro-proliferative, and pro-angiogenic agents, enhancing ALF alleviation and providing an optimal microenvironment for MSC transplantation. Additionally, a methacrylic anhydride (MA)-modified porcine liver-derived decellularized extracellular matrix (PLdECM) hydrogel (PLdECMMA) has been developed for the construction of microgels via microfluidic devices. Interferon γ (IFNγ) preconditioned MSCs encapsulated in PLdECMMA microgels exhibit enhanced immunomodulating activity and prolonged survival. PtCu-DHLA nanozymes and cell-laden microgels are codelivered by leveraging the PLdECM hydrogel for orthotopic transplantation. The transplanted dECM platform enables an efficient and successful rescue of CCl4-induced ALF by counteracting oxidative stress, suppressing inflammatory storms, and promoting cellular regeneration. Overall, this study highlights a synergistic and reinforced strategy that combines biomimetic nanozymes with MSC therapy, offering significant potential for ALF treatment and broader applications in regenerative medicine.

With the exacerbation of the aging population trend, a series of neurodegenerative diseases caused by brain aging have become increasingly common, significantly impacting the daily lives of the elderly and imposing heavier burdens on nations and societies. Brain aging is a complex process involving multiple mechanisms, including oxidative stress, apoptosis of damaged neuronal cells, chronic inflammation, and mitochondrial dysfunction, and research into new therapeutic strategies to delay brain aging has gradually become a research focus in recent years. Mesenchymal stem cells (MSCs) have been widely used in cell therapy due to their functions such as antioxidative stress, anti-inflammation, and tissue regeneration. However, accompanying safety issues such as immune rejection, tumor development, and pulmonary embolism cannot be avoided. Studies have shown that using exosome derived from mesenchymal stem cells (MSC-Exo) for the treatment of neurodegenerative diseases is a safe and effective method. It not only has the therapeutic effects of stem cells but also avoids the risks associated with cell therapy. Therefore, exploring new therapeutic strategies to delay normal brain aging from the mechanism of MSC-Exo in the treatment of neurodegenerative diseases is feasible. This review summarizes the characteristics of MSC-Exo and their clinical progress in the treatment of neurodegenerative diseases, aiming to explore the possibility and potential mechanisms of MSC-Exo in reversing brain aging.

Central nervous system (CNS) diseases, such as brain tumors, Alzheimer's disease, and Parkinson's disease, significantly impact patients' quality of life and impose substantial economic burdens on society. The blood-brain barrier (BBB) limits the effective delivery of most therapeutic drugs, especially natural products, despite their potential therapeutic effects. The Trojan Horse strategy, using nanotechnology to disguise drugs as "cargo", enables them to bypass the BBB, enhancing targeting and therapeutic efficacy. This review explores the applications of natural products in the treatment of CNS diseases, discusses the challenges posed by the BBB, and analyzes the advantages and limitations of the Trojan Horse strategy. Despite the existing technical challenges, future research is expected to enhance the application of natural drugs in CNS treatment by integrating nanotechnology, improving delivery mechanisms, and optimizing targeting characteristics.

Articular cartilage repair and regeneration is still a significant challenge despite years of research. Although microfracture techniques are commonly used in clinical practice, the newborn cartilage is usually fibrocartilage rather than hyaline cartilage, which is mainly attributed to the inadequate microenvironment for effectively recruiting, anchoring, and inducing bone marrow mesenchymal stem cells (BMSCs) to differentiate into hyaline cartilage. This paper introduces a novel cartilage acellular matrix (CACM) microgel assembly with excellent microporosity, injectability, tissue adhesion, BMSCs recruitment and chondrogenic differentiation capabilities to improve the microfracture-based articular cartilage regeneration. Specifically, the sustained release of simvastatin (SIM) from the SIM@CACM microgel assembly efficiently recruits BMSCs in the early stage of cartilage regeneration, while the abundant interconnected micropores and high specific area assure the quick adhesion, proliferation and infiltration of BMSCs. Additionally, the active factors within the CACM matrix, appropriate mechanical properties of the microgel assembly, and excellent tissue adhesion provide a conductive environment for the continuous chondrogenic differentiation of BMSCs into hyaline cartilage. Owing to the synergistic effect of the above-mentioned factors, good articular cartilage repair and regeneration is achieved.

Acute Myocardial Infarction (AMI) has seen rising cases, particularly in younger people, leading to public health concerns. Standard treatments, like coronary artery recanalization, often don't fully repair the heart's microvasculature, risking heart failure. Advances show that Mesenchymal Stromal Cells (MSCs) transplantation improves cardiac function after AMI, but the harsh microenvironment post-AMI impacts cell survival and therapeutic results. MSCs aid heart repair via their membrane proteins and paracrine extracellular vesicles that carry microRNA-125b, which regulates multiple targets, preventing cardiomyocyte death, limiting fibroblast growth, and combating myocardial remodeling after AMI. This study introduces ultrasound-responsive phase-change bionic nanoparticles, leveraging MSCs' natural properties. These particles contain MSC membrane and microRNA-125b, with added macrophage membrane for stability. Using Ultrasound Targeted Microbubble Destruction (UTMD), this method targets the delivery of MSC membrane proteins and microRNA-125b to AMI's inflamed areas. This aims to enhance cardiac function recovery and provide precise, targeted AMI therapy.

The heterogeneity of human umbilical cord mesenchymal stem cells (hUC-MSCs) is culturing-dependent, resulting in functional non-uniformness. To achieve the best clinical benefit, a comprehensive understanding of the origin of the heterogeneity in different culture systems can identify functional subgroups to direct the precise application of hUC-MSCs. Here, we create a single-cell transcriptome atlas of hUC-MSC in different culture systems for the identification of a subgroup of Ultroser-G-MSCs with high osteogenic and chondrogenic potentials featured by high expressions of IL1R1 and PDGFRA. Further experimental validations surprisingly reveal that IL1R1highPDGFRAhigh Ultroser-G-MSCs possess advantages over "traditional" hUC-MSCs in the treatments of modeled osteoarthritis, leading to a cell-cell communication network centered in Clusters 0 and 2. Moreover, we found that Wnt5 signaling is the key pathway for the dynamic transformation of osteogenic and chondrogenic phenotypes in hUC-MSC. Overall, the present study paves the way for the clarification of heterogenetic nature of hUC-MSC in different culture systems for the selection of optimal MSC types to achieve the precision on clinical treatments.

Periodontal disease is characterized by chronic inflammation and destruction of supporting periodontal tissues, ultimately leading to tooth loss. In recent years, "cell-free treatment" without stem cell transplantation has attracted considerable attention for tissue regeneration. This study investigated the effects of extracts of mesenchymal stem cells (MSC-extract) and their protein components (MSC-protein) on the proliferation and migration of periodontal ligament (PDL) cells and whether MSC-protein can induce periodontal regeneration.

MSC-extract and MSC-protein were obtained by subjecting mesenchymal stem cells (MSCs) to freeze-thaw cycles and acetone precipitation. Cell proliferation was examined using a WST-8 assay and Ki67 immunostaining, and cell migration was examined using Boyden chambers. The MSC-protein content was analyzed using liquid chromatography-mass spectrometry, protein arrays, and enzyme-linked immunosorbent assays (ELISAs). Gene expression in MSC-protein-treated PDL cells was examined using RNA-sequencing and Gene Ontology analyses. The regenerative potential of MSC-protein was examined using micro-computer tomography (CT) and histological analyses after transplantation into a rat periodontal defect model.

MSC-extract and MSC-protein promoted the proliferation and migration of PDL cells. Protein array and ELISA revealed that MSC-protein contained high concentrations of basic fibroblast growth factor (bFGF) and hepatocyte growth factor (HGF). Exogenous bFGF promoted the proliferation and migration of PDL cells. Furthermore, the transplantation of MSC-protein enhanced periodontal tissue regeneration with the formation of new alveolar bone and PDLs.

These results indicate that the MSC-protein promotes the proliferation and migration of PDL cells and induces significant periodontal tissue regeneration, suggesting that the MSC-protein could be used as a new cell-free treatment for periodontal disease.

Chronic wound poses a serious risk to diabetic patients, primarily due to damaged skin microvasculature and prolonged inflammation at the wound site. Mesenchymal stem cell (MSC) therapy utilizing microgels as a cell delivery system has shown promise in promoting wound healing by enhancing cell viability and the secretion of bioactive factors. Retaining sufficient MSCs at injury sites is crucial for optimal therapeutic outcomes. However, inadequate hierarchical structure and limited use of the microgel's interior space significantly reduce cell proliferation and infiltration efficiency, thereby compromising the therapeutic effect. To address this, a microfluidic approach is developed for fabricating porous hierarchical interconnected microgels with interior spiral canals (PHIGels) by employing a fluidic "viscous instability" effect and gas formation reaction during the microfluidic synthesis. These MSC-laden PHIGel scaffolds facilitate rapid proliferation and infiltration into the interior spiral canals through a hierarchical pore network, significantly increasing the number of viable cells that can be carried by the microgels. It is proved that these microgel-based deliveries of MSCs promote re-epithelialization, collagen synthesis, angiogenesis, and reduction in inflammation, thus enhancing cutaneous wound repair in a rat model of type I diabetes. The microporosity and hierarchical design of these microgels offer novel routes for tissue regeneration and repair.

Despite many years of investigation into mesenchymal stem cells (MSCs) and their potential for treating inflammatory conditions such as COVID-19, clinical outcomes remain variable due to factors like donor variability, different tissue sources, and diversity within MSC populations. Variations in MSCs' secretory and proliferation profiles, and their proteomic and transcriptional characteristics significantly influence their therapeutic potency, highlighting the need for enhanced characterization methods to better predict their efficacy. This study aimed to evaluate the biological characteristics of MSCs from different tissue origins, selecting the most promising line for further validation in a K18-hACE2 mouse model of SARS-CoV-2 infection.

We studied nine MSC lines sourced from either bone marrow (hBMMSC), dental pulp (hDPMSC), or umbilical cord tissue (hUCMSC). The cells were assessed for their proliferative capacity, immunophenotype, trilineage differentiation, proteomic profile, and in vitro immunomodulatory potential by co-culture with activated lymphocytes. The most promising MSC line was selected for further experimental validation using the K18-hACE2 mouse model of SARS-CoV-2 infection.

The analyzed cells met the minimum criteria for defining MSCs, including the expression of surface molecules and differentiation capacity, showing genetic stability and proliferative potential. Proteomic analysis revealed distinct protein profiles that correlate with the tissue origin of MSCs. The immunomodulatory response exhibited variability, lacking a discernible pattern associated with their origin. In co-culture assays with lymphocytes activated with anti-CD3/CD28 beads, all MSC lines demonstrated the ability to inhibit TNF-α, to induce TGF-β and Indoleamine 2,3-dioxygenase (IDO), with varying degrees of inhibition observed for IFN-γ and IL-6, or induction of IL-10 expression. A module of proteins was found to statistically correlate with the potency of IL-6 modulation, leading to the selection of one of the hUCMSCs as the most promising line. Administration of hUCMSC to SARS-CoV-2-infected K18 mice expressing hACE2 was effective in improving lung histology and modulating of a panel of cytokines.

Our study assessed MSCs derived from various tissues, uncovering significant variability in their characteristics and immunomodulatory capacities. Particularly, hUCMSCs demonstrated potential in mitigating lung pathology in a SARS-CoV-2 infection model, suggesting their promising therapeutic efficacy.

The generation of myogenic progenitors from iPSCs (iMPs) with therapeutic potential for in vivo tissue regeneration has long been a goal in the skeletal muscle community. Today, protocols enable the production of potent, albeit immature, iMPs that resemble Pax7+ adult muscle stem cells. While muscular dystrophies are often the primary therapeutic target for these cells, an underexplored application is their use in treating traumatic muscle injuries. Notably absent from recent reviews on iMPs is the concept of engineering these cells to perform functions post-transplantation that non-transgenic cells cannot. Here, we highlight protocols to enhance the generation, purification, and maturation of iMPs, and introduce the idea of engineering these cells to perform functions beyond their normal capacities, envisioning novel therapeutic applications.

Osteoarthritis (OA) is a prevalent joint disorder that lacks effective therapies to halt cartilage degeneration. Mesenchymal stromal cell (MSC)-derived small extracellular vesicles (sEVs) are being investigated as promising chondroprotective agents. Compared to primary MSCs, induced pluripotent stem cell (iPSC)-derived MSCs (MLCs) offer superior scalability and enhanced paracrine activity. The aim of this study was to explore the feasibility of using autologous MLC-derived sEVs as a potential therapeutic strategy for OA through the analysis of their protein cargo. iPSCs from an OA patient and a healthy donor were differentiated into MLCs. sEVs were isolated from these MLCs and characterized, with a particular focus on their protein cargo. Both iPSC lines were successfully differentiated into MLCs, which secreted sEVs with comparable size distributions and yields. The analysis of differentially expressed proteins revealed a high abundance of proteins associated with OA pathology and cartilage degradation in sEVs from OA MLCs compared to those from healthy MLCs. The persistence of OA-associated protein signatures in autologous MLC-derived sEVs may limit their therapeutic efficacy. These findings underscore the importance of carefully evaluating disease-specific protein profiles in sEVs for regenerative applications.

Defining the mechanism of immune modulation by mesenchymal stromal cells (MSCs) from distinct anatomical tissues is of great translational interest. The human cornea is an immunologically privileged organ, and the mechanism of immunoregulation of cornea-derived MSCs (cMSCs) is currently unknown. We investigated cMSCs derived from the corneas of 5 independent human donorS for their fitness and mechanism of action in suppressing T cells. cMSCs display the immunophenotype CD45-CD73+CD105+CD90+CD44+ and robust in vitro growth. 30-plex secretome analysis identified that cMSCs innately secrete specific molecules in a dose-dependent manner. cMSCs do not express or upregulate costimulatory but do upregulate coinhibitory molecules upon stimulation with interferon γ (IFNγ). cMSCs inhibit T-cell proliferation in contact-dependent co-cultures, which can be predicted by a unique secretome signature. In addition, co-culturing in a 2-chamber transwell system has demonstrated that cMSCs also inhibit T-cell proliferation in a non-contact-dependent manner. Mechanistic analysis has demonstrated that activated T cells effectively induce indoleamine 2,3-dioxygenase (IDO) but not other enzymes of the tryptophan metabolic pathway in cMSCs. Silencing of IDO in cMSCs reduces their fitness to suppress T cells. These results provide evidence that in cMSCs, one of the principal mechanisms of immunosuppression on T cells is through IDO. These results suggest that MSCs derived from the human cornea display immunoregulatory properties and, thus, may play a role in maintaining the immune-privileged niche of the cornea.

Increasing evidence shows extracellular vesicles (EVs) are primarily responsible for the beneficial effects of cell-based therapies. EVs derived from mesenchymal stromal cells (MSCs) show promise as a source of EVs for cell-free therapies. The human placental fetal-maternal interface is a rich and abundant source of MSCs from which EVs can be isolated. This study focusses on chorionic MSCs (CMSC) located on the fetal aspect of the interface and decidual MSCs (DMSC) on the maternal aspect. This study used Ligand-based Exosome Affinity Purification (LEAP) chromatography to isolate EVs from well-characterized placental hTERT-transduced CMSC29 and DMSC23 cell lines, which retain many important stem cell-like properties of primary CMSC and DMSC, respectively. After initial biophysical characterization of the EVs isolated from each cell line, the biological activities and the protein, lipid and small RNA contents of CMSC29-EVs and DMSC23-EVs were compared and assessed. LEAP-purified EVs from both sources were validated at the biophysical level by Spectradyne, Cryo-Transmission Electron Microscopy (Cryo-TEM), and Western blot analysis. EVs from each type were labelled with the live cell stain PKH26 and their in vitro uptake and internalization by human dermal fibroblast cells was assessed, as well as their phosphorylation of the protein kinase B/AKT (AKT) pathway. The protein and lipid contents were analyzed by mass spectrometry and the nucleic acid content by RNA sequencing (RNA-seq). Lastly, the biological activities of the EVs were evaluated in a BioMAP® Diversity PLUS® screen system across a panel of 12 human primary cell-based systems and in vitro cell proliferation. EVs isolated from both DMSC23 and CMSC29 significantly increased proliferation of fibroblasts and showed phosphorylation of the AKT pathway. Protein mass spectrometry analysis identified a large number of proteins including cell surface receptors, cytokines, chemokines, matrix molecules and enzymes in both EV types. Lipidomic analysis identified species including phosphatidylcholine, triacylglycerides and diacylglycerides in both DMSC23 and CMSC29-derived EVs. There were some significant differences in identified microRNAs (miRNAs) between the two EV types. The top differentially expressed miRNAs between the two EV types show pathways association with matrix interaction, transcriptional regulation, proliferation, cellular protein modification processes, and vasculogenesis. Differences were also detected between DMSC23- and CMSC29-EVs in the biological activity they displayed in the BioMAP® Diversity PLUS® screen.

There is currently no definitive treatment for osteoarthritis. We examined the therapeutic effects and underlying mechanisms of platelet-rich plasma (PRP) and adipose-derived mesenchymal stem cells (ADSCs), individually or in combination, in a rat model of anterior cruciate ligament-induced degenerative osteoarthritis (OA) of the knee. This study seeks to advance clinical approaches to OA treatment.

Eight- to nine-week-old male Sprague-Dawley (SD) rats were randomly assigned to two groups: (1) a normal control group (Group A) and (2) a model group. The control group received no treatment. The model group underwent treatment and was further subdivided into six groups: Group B (an injury control group), Group C (high-dose ADSCs), Group D (PRP combined with high-dose ADSCs), Group E (low-dose ADSCs), Group F (PRP combined with low-dose ADSCs), and Group G (PRP alone). PRP and/or ADSCs were administered via intra-articular injection on Days 7, 37, and 67 post-surgery. Daily observations recorded activity levels and behavior, while weight changes were monitored weekly. Digital radiography (DR) was conducted on Days 30, 60, and 90 post-surgery to assess joint surface and contour alterations. Histopathological examination and inflammatory factor analysis were performed on cartilage and synovial tissue.

No abnormal reactions were observed in any rats, and body weights increased as expected (P > 0.05). Significant differences in knee swelling rates and Wakitani scores were observed between Groups A and B (P < 0.01). Knee swelling rates also differed significantly between Group B and Groups C-G (P < 0.01). Wakitani scores decreased on Days 60 and 90 in Groups C-G. TNF-α and IL-1β expression levels were significantly higher in Group B compared to Group A (P < 0.05). Expression levels of these genes were significantly lower in Groups C-G than in Group B (P < 0.05).

Repeated intra-articular injections of PRP and ADSCs alleviated inflammation and pain, promoted tissue repair, and modulated immune responses in rats with surgically induced OA. The combination of PRP and ADSCs demonstrated enhanced therapeutic efficacy, suggesting its potential as a treatment option for OA.

Mesenchymal stromal cell (MSC) therapy has regenerative potentials to treat various pathological conditions including neurological diseases. MSCs isolated from various organs can differentiate into specific cell types to repair organ damages. However, their paracrine mechanisms are predicted to predominantly mediate their immunomodulatory, proangiogenic, and regenerative properties. While preclinical studies highlight the significant potential of MSC therapy in mitigating neurological damage from stroke and traumatic brain injury, the variability in clinical trial outcomes may stem from the inherent heterogeneity of somatic MSCs. Accumulating evidence has demonstrated that induced pluripotent stem cells (iPSCs) are an ideal alternative resource for the unlimited expansion and biomanufacturing of MSCs. Thus, we investigated how iPSC-derived MSCs (iMSCs) influence properties of iPSC-derived neurons. Our findings demonstrate that the secretome from iMSCs possesses neurotrophic effects, improving neuronal survival and promoting neuronal outgrowth and synaptic activity in vitro. Additionally, the iMSCs enhance metabolic activity via mitochondrial respiration in neurons, both in vitro and in mouse models. Glycolytic pathways also increased following the administration of iMSC secretome to iPSC-derived neurons. Consistently, in vivo experiments showed that intravenous administration of iMSCs compensated for the elevated energetic demand in male mice with irradiation-induced brain injury by restoring synaptic metabolic activity during acute brain damage. 18F-FDG PET imaging also detected an increase in brain glucose uptake following iMSC administration. Together, our results highlight the potential of iMSC-based therapy in treating neuronal damage in various neurological disorders, while paving the way for future research and potential clinical applications of iMSCs in regenerative medicine.

Diabetic wounds present a significant challenge in regenerative medicine due to impaired healing, characterized by prolonged inflammation and deficient tissue repair, primarily caused by a skewed pro-inflammatory macrophage phenotype. This study investigates the therapeutic potential of interleukin-10 (IL-10) chemically modified mRNA (modRNA)-enriched human adipose-derived multipotent stromal cells (hADSCs) in a well-established murine model of diabetic wounds. The modRNAs used in this study were chemically modified using N1-methylpseudouridine-5'-triphosphate (m1Ψ) by substituting uridine-5-triphosphate. In vitro experiments demonstrated that IL-10 modRNA-transfected hADSCs effectively modulated macrophage polarization towards an anti-inflammatory phenotype. In vivo experiments with a well-established murine model demonstrated that transplantation of hADSCsmodIL-10 on postoperative day 5 (POD5) significantly improved wound healing outcomes, including accelerated wound closure, enhanced re-epithelialization, promoted M2 polarization, improved collagen deposition, and increased neovascularization. This study concludes that IL-10 modRNA-enriched hADSCs offer a promising therapeutic approach for diabetic wound healing, with the timing of IL-10 administration playing a crucial role in its effectiveness. These cells modulate macrophage polarization and promote tissue repair, demonstrating their potential for improving the management of diabetic wounds.