Current Perspectives on Adult Mesenchymal Stromal Cell-Derived Extracellular Vesicles: Biological Features and Clinical Indications

Improving the Wound Healing Process: Pivotal role of Mesenchymal stromal/stem Cells and Immune Cells

Wound healing, a physiological process, involves several different types of cells, from immune cells to non-immune cells, including mesenchymal stromal/stem cells (MSC), and their interactions. Immune cells including macrophages, neutrophils, dendritic cells (DC), innate lymphoid cells (ILC), natural killer (NK) cells, and B and T lymphocytes participate in wound healing by secreting various mediators and interacting with other cells. MSCs, as self-renewing, fast proliferating, and multipotent stromal/stem cells, are found in a wide variety of tissues and critically involved in different phases of wound healing by secreting various molecules that help to improve tissue healing and regeneration. In this review, first, we described the four main phases of wound healing, second, we reviewed the function of MSCs, MSC secretome and immune cells in improving the progress of wound repair (mainly focusing on skin wound healing), third, we explained the immune cells/MSCs interactions in the process of wound healing and regeneration, and finally, we introduce clinical applications of MSCs to improve the process of wound healing.

Dynamic conditioning of porcine kidney grafts with extracellular vesicles derived from urine progenitor cells: A proof-of-concept study

 : Among strategies to limit ischemia/reperfusion (IR) injuries in transplantation, cell therapy using stem cells to condition/repair transplanted organs appears promising. We hypothesized that using a cell therapy based on extracellular vesicles (EVs) derived from urine progenitor cells (UPCs) during hypothermic and normothermic machine perfusion can prevent IR-related kidney damage. We isolated and characterized porcine UPCs and their extracellular vesicles (EVs). Then these were used in an ex vivo porcine kidney preservation model. Kidneys were subjected to warm ischemia (32 min) and then preserved by hypothermic machine perfusion (HMP) for 24 h before 5 h of normothermic machine perfusion (NMP). Three groups were performed (n = 5-6): Group 1 (G1): HMP/vehicle + NMP/vehicle, Group 2 (G2): HMP/EVs + NMP/vehicle, Group 3 (G3): HMP/EVs + NMP/EVs. Porcine UPCs were successfully isolated from urine and fully characterized as well as their EVs which were found of expected size/phenotype. EVs injection during HMP alone, NMP alone, or both was feasible and safe and did not impact perfusion parameters. However, cell damage markers (LDH, ASAT) were decreased in G3 compared with G1, and G3 kidneys displayed a preserved tissue integrity with reduced tubular dilatation and inflammation notably. However, renal function indicators such as creatinine clearance measured for 5 h of normothermic perfusion or NGAL perfusate's level were not modified by EVs injection. Regarding perfusate analysis, metabolomic analyses and cytokine quantification showed an immunomodulation signature in G3 compared with G1 and highlighted potential metabolic targets. In vitro, EVs as well as perfusates from G3 partially recovered endothelial cell metabolic activity after hypoxia. Finally, RNA-seq performed on kidney biopsies showed different profiles between G1 and G3 with regulation of potential IR targets of EVs therapy. We showed the feasibility/efficacy of UPC-EVs for hypothermic/normothermic kidney conditioning before transplantation, paving the way for combining machine perfusion with EVs-based cell therapy for organ conditioning. HIGHLIGHTS: ·UPCs from porcine urine can be used to generate a cell therapy product based on extracellular vesicles (pUPC-EVs). ·pUPC-EVs injection during HMP and NMP decreases cell damage markers and has an immunomodulatory effect. ·pUPC-EVs-treated kidneys have distinct biochemical, metabolic, and transcriptomic profiles highlighting targets of interest. ·Our results pave the way for combining machine perfusion with EV-based cell therapy for kidney conditioning.

Proteomic analysis and functional validation reveal distinct therapeutic capabilities related to priming of mesenchymal stromal/stem cells with IFN-γ and hypoxia: potential implications for their clinical use

Mesenchymal stromal/stem cells (MSCs) are a heterogeneous population of multipotent cells that can be obtained from various tissues, such as dental pulp, adipose tissue, bone marrow and placenta. MSCs have gained importance in the field of regenerative medicine because of their promising role in cell therapy and their regulatory abilities in tissue repair and regeneration. However, a better characterization of these cells and their products is necessary to further potentiate their clinical application. In this study, we used unbiased high-resolution mass spectrometry-based proteomic analysis to investigate the impact of distinct priming strategies, such as hypoxia and IFN-γ treatment, on the composition and therapeutic functionality of the secretome produced by MSCs derived from the amniotic membrane of the human placenta (hAMSCs). Our investigation revealed that both types of priming improved the therapeutic efficacy of hAMSCs, and these improvements were related to the secretion of functional factors present in the conditioned medium (CM) and exosomes (EXOs), which play crucial roles in mediating the paracrine effects of MSCs. In particular, hypoxia was able to induce a pro-angiogenic, innate immune response-activating, and tissue-regenerative hAMSC phenotype, as highlighted by the elevated production of regulatory factors such as VEGFA, PDGFRB, ANGPTL4, ENG, GRO-γ, IL8, and GRO-α. IFN-γ priming, instead, led to an immunosuppressive profile in hAMSCs, as indicated by increased levels of TGFB1, ANXA1, THBS1, HOMER2, GRN, TOLLIP and MCP-1. Functional assays validated the increased angiogenic properties of hypoxic hAMSCs and the enhanced immunosuppressive activity of IFN-γ-treated hAMSCs. This study extends beyond the direct priming effects on hAMSCs, demonstrating that hypoxia and IFN-γ can influence the functional characteristics of hAMSC-derived secretomes, which, in turn, orchestrate the production of functional factors by peripheral blood cells. This research provides valuable insights into the optimization of MSC-based therapies by systematically assessing and comparing the priming type-specific functional features of hAMSCs. These findings highlight new strategies for enhancing the therapeutic efficacy of MSCs, particularly in the context of multifactorial diseases, paving the way for the use of hAMSC-derived products in clinical practice.

Extracellular Vesicles in Lung Cancer: Implementation in Diagnosis and Therapeutic Perspectives

Lung cancer represents the leading cause of cancer-related mortality worldwide, with around 1.8 million deaths in 2020. For this reason, there is an enormous interest in finding early diagnostic tools and novel therapeutic approaches, one of which is extracellular vesicles (EVs). EVs are nanoscale membranous particles that can carry proteins, lipids, and nucleic acids (DNA and RNA), mediating various biological processes, especially in cell-cell communication. As such, they represent an interesting biomarker for diagnostic analysis that can be performed easily by liquid biopsy. Moreover, their growing dataset shows promising results as drug delivery cargo. The aim of our work is to summarize the recent advances in and possible implications of EVs for early diagnosis and innovative therapies for lung cancer.

Hsp70 and Calcitonin Receptor Protein in Extracellular Vesicles from Glioblastoma Multiforme: Biomarkers with Putative Roles in Carcinogenesis and Potential for Differentiating Tumor Types

Glioblastoma multiforme (GBM) is a malignancy of bad prognosis, and advances in early detection and treatment are needed. GBM is heterogenous, with varieties differing in malignancy within a tumor of a patient and between patients. Means are needed to distinguish these GMB forms, so that specific strategies can be deployed for patient management. We study the participation of the chaperone system (CS) in carcinogenesis. The CS is dynamic, with its members moving around the body in extracellular vesicles (EVs) and interacting with components of other physiological systems in health and disease, including GBM. Here, we describe the finding of high amounts of Hsp70 (HSPA1A) and the calcitonin receptor protein (CTR) in EVs in patients with GBM. We present a standardized protocol for collecting, purifying, and characterizing EVs carrying Hsp70 and CTR in plasma-derived EVs from patients with GBM. EVs from GBM patients were obtained just before tumor ablative surgery (T0) and 7 days afterwards (T1); Hsp70 was highly elevated at T0 and less so at T1, and CTR was greatly increased at T0 and reduced to below normal values at T1. Our results encourage further research to assess Hsp70 and CTR as biomarkers for differentiating tumor forms and to determine their roles in GBM carcinogenesis.

The mechanism of adipose mesenchymal stem cells to stabilize the immune microenvironment of pelvic floor injury by regulating pyroptosis and promoting tissue repair

Pelvic organ prolapse (POP) has a high incidence rate among Chinese women. Repeated mechanical stimulation is an important factor causing POP, but the injury mechanism has not yet been elucidated. The purpose of this study is to explore the related mechanisms of pelvic floor supporting tissue damage caused by mechanical force and the application of stem cell therapy. First, we obtained vaginal wall and sacral ligament tissue samples from clinical patients for examination. Pelvic floor support tissues of POP patients displayed high expression of inflammation and immune disorders. Then, we constructed a rat model of childbirth injury. In vivo and in vitro experiments investigated the key mechanism of pelvic floor support tissue injury caused by mechanical force. We discovered that after mechanical force, a large number of reactive oxygen species (ROS) and macrophages rapidly accumulated in pelvic floor tissues. ROS stimulated macrophages to produce NLRP3 inflammatory complex, induced the release of interleukin (IL-1β) and pyroptosis and exacerbated the inflammatory state of damaged tissues, persisting chronic inflammation of fibroblasts in supporting tissues, thus causing the pelvic floor's extracellular matrix (ECM) collagen metabolic disorder. Resultingly impeding the repair process, thereby causing the onset and progression of the disease. Through their paracrine ability, we discovered that adipose mesenchymal stem cells (ADSCs) could inhibit this series of pathological processes and promote tissue repair, asserting a good therapeutic effect. Simultaneously, to overcome the low cell survival rate and poor therapeutic effect of directly injecting cells, we developed a ROS-responsive PVA@COLI hydrogel with ADSCs. The ROS-scavenging properties of the gel could reshape the site of inflammation injury, enhance cell survival, and play a role in subsequent treatment. The findings of this study could serve as a basis for early, targeted intervention therapy for POP and representing a promising approach.

Use of priming strategies to advance the clinical application of mesenchymal stromal/stem cell-based therapy

Mesenchymal stromal/stem cells (MSCs) have garnered significant attention in the field of regenerative medicine due to their remarkable therapeutic potential. MSCs play a pivotal role in maintaining tissue homeostasis and possess diverse functions in tissue repair and recovery in various organs. These cells are characterized by easy accessibility, few ethical concerns, and adaptability to in vitro cultures, making them a valuable resource for cell therapy in several clinical conditions. Over the years, it has been shown that the true therapeutic power of MSCs lies not in cell engraftment and replacement but in their ability to produce critical paracrine factors, including cytokines, growth factors, and exosomes (EXOs), which modulate the tissue microenvironment and facilitate repair and regeneration processes. Consequently, MSC-derived products, such as conditioned media and EXOs, are now being extensively evaluated for their potential medical applications, offering advantages over the long-term use of whole MSCs. However, the efficacy of MSC-based treatments varies in clinical trials due to both intrinsic differences resulting from the choice of diverse cell sources and non-standardized production methods. To address these concerns and to enhance MSC therapeutic potential, researchers have explored many priming strategies, including exposure to inflammatory molecules, hypoxic conditions, and three-dimensional culture techniques. These approaches have optimized MSC secretion of functional factors, empowering them with enhanced immunomodulatory, angiogenic, and regenerative properties tailored to specific medical conditions. In fact, various priming strategies show promise in the treatment of numerous diseases, from immune-related disorders to acute injuries and cancer. Currently, in order to exploit the full therapeutic potential of MSC therapy, the most important challenge is to optimize the modulation of MSCs to obtain adapted cell therapy for specific clinical disorders. In other words, to unlock the complete potential of MSCs in regenerative medicine, it is crucial to identify the most suitable tissue source and develop in vitro manipulation protocols specific to the type of disease being treated.

Chemical Transdifferentiation of Somatic Cells: Unleashing the Power of Small Molecules

Chemical transdifferentiation is a technique that utilizes small molecules to directly convert one cell type into another without passing through an intermediate stem cell state. This technique offers several advantages over other methods of cell reprogramming, such as simplicity, standardization, versatility, no ethical and safety concern and patient-specific therapies. Chemical transdifferentiation has been successfully applied to various cell types across different tissues and organs, and its potential applications are rapidly expanding as scientists continue to explore new combinations of small molecules and refine the mechanisms driving cell fate conversion. These applications have opened up new possibilities for regenerative medicine, disease modeling, drug discovery and tissue engineering. However, there are still challenges and limitations that need to be overcome before chemical transdifferentiation can be translated into clinical practice. These include low efficiency and reproducibility, incomplete understanding of the molecular mechanisms, long-term stability and functionality of the transdifferentiated cells, cell-type specificity and scalability. In this review, we compared the commonly used methods for cell transdifferentiation in recent years and discussed the current progress and future perspective of the chemical transdifferentiation of somatic cells and its potential impact on biomedicine. We believe that with ongoing research and technological advancements, the future holds tremendous promise for harnessing the power of small molecules to shape the cellular landscape and revolutionize the field of biomedicine.

The Truth Is Out There: Biological Features and Clinical Indications of Extracellular Vesicles from Human Perinatal Stem Cells

The potential of perinatal tissues to provide cellular populations to be used in different applications of regenerative medicine is well established. Recently, the efforts of researchers are being addressed regarding the evaluation of cell products (secreted molecules or extracellular vesicles, EVs) to be used as an alternative to cellular infusion. The data regarding the effective recapitulation of most perinatal cells' properties by their secreted complement point in this direction. EVs secreted from perinatal cells exhibit key therapeutic effects such as tissue repair and regeneration, the suppression of inflammatory responses, immune system modulation, and a variety of other functions. Although the properties of EVs from perinatal derivatives and their significant potential for therapeutic success are amply recognized, several challenges still remain that need to be addressed. In the present review, we provide an up-to-date analysis of the most recent results in the field, which can be addressed in future research in order to overcome the challenges that are still present in the characterization and utilization of the secreted complement of perinatal cells and, in particular, mesenchymal stromal cells.

Facing the Challenges in the COVID-19 Pandemic Era: From Standard Treatments to the Umbilical Cord-Derived Mesenchymal Stromal Cells as a New Therapeutic Strategy

Coronavirus disease 2019 (COVID-19), the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which counts more than 650 million cases and more than 6.6 million of deaths worldwide, affects the respiratory system with typical symptoms such as fever, cough, sore throat, acute respiratory distress syndrome (ARDS), and fatigue. Other nonpulmonary manifestations are related with abnormal inflammatory response, the "cytokine storm", that could lead to a multiorgan disease and to death. Evolution of effective vaccines against SARS-CoV-2 provided multiple options to prevent the infection, but the treatment of the severe forms remains difficult to manage. The cytokine storm is usually counteracted with standard medical care and anti-inflammatory drugs, but researchers moved forward their studies on new strategies based on cell therapy approaches. The perinatal tissues, such as placental membranes, amniotic fluid, and umbilical cord derivatives, are enriched in mesenchymal stromal cells (MSCs) that exert a well-known anti-inflammatory role, immune response modulation, and tissue repair. In this review, we focused on umbilical-cord-derived MSCs (UC-MSCs) used in in vitro and in vivo studies in order to evaluate the weakening of the severe symptoms, and on recent clinical trials from different databases, supporting the favorable potential of UC-MSCs as therapeutic strategy.

Different priming strategies improve distinct therapeutic capabilities of mesenchymal stromal/stem cells: Potential implications for their clinical use

Mesenchymal stromal/stem cells (MSCs) have shown significant therapeutic potential, and have therefore been extensively investigated in preclinical studies of regenerative medicine. However, while MSCs have been shown to be safe as a cellular treatment, they have usually been therapeutically ineffective in human diseases. In fact, in many clinical trials it has been shown that MSCs have moderate or poor efficacy. This inefficacy appears to be ascribable primarily to the heterogeneity of MSCs. Recently, specific priming strategies have been used to improve the therapeutic properties of MSCs. In this review, we explore the literature on the principal priming approaches used to enhance the preclinical inefficacy of MSCs. We found that different priming strategies have been used to direct the therapeutic effects of MSCs toward specific pathological processes. Particularly, while hypoxic priming can be used primarily for the treatment of acute diseases, inflammatory cytokines can be used mainly to prime MSCs in order to treat chronic immune-related disorders. The shift in approach from regeneration to inflammation implies, in MSCs, a shift in the production of functional factors that stimulate regenerative or anti-inflammatory pathways. The opportunity to fine-tune the therapeutic properties of MSCs through different priming strategies could conceivably pave the way for optimizing their therapeutic potential.

Role of Mesenchymal Stem/Stromal Cells in Modulating Ischemia/Reperfusion Injury: Current State of the Art and Future Perspectives

Ischemia/reperfusion injury (IRI) is a multistep damage that occurs in several tissues when a blood flow interruption is inevitable, such as during organ surgery or transplantation. It is responsible for cell death and tissue dysfunction, thus leading, in the case of transplantation, to organ rejection. IRI takes place during reperfusion, i.e., when blood flow is restored, by activating inflammation and reactive oxygen species (ROS) production, causing mitochondrial damage and apoptosis of parenchymal cells. Unfortunately, none of the therapies currently in use are definitive, prompting the need for new therapeutic approaches. Scientific evidence has proven that mesenchymal stem/stromal cells (MSCs) can reduce inflammation and ROS, prompting this cellular therapy to also be investigated for treatment of IRI. Moreover, it has been shown that MSC therapeutic effects were mediated in part by their secretome, which appears to be involved in immune regulation and tissue repair. For these reasons, mediated MSC paracrine function might be key for injury amelioration upon IRI damage. In this review, we highlight the scientific literature on the potential beneficial use of MSCs and their products for improving IRI outcomes in different tissues/organs, focusing in particular on the paracrine effects mediated by MSCs, and on the molecular mechanisms behind these effects.