The mesenchymal stem cell secretome: A new paradigm towards cell-free therapeutic mode in regenerative medicine. Cytokine Growth Factor Rev. 2019;46:1-9. [PMID: 30954374 DOI: 10.1016/j.cytogfr.2019.04.002]

miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow-derived neural crest cells

JOURNAL/nrgr/04.03/01300535-202501000-00035/figure1/v/2024-05-14T021156Z/r/image-tiff Our previous study found that rat bone marrow-derived neural crest cells (acting as Schwann cell progenitors) have the potential to promote long-distance nerve repair. Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication. Nevertheless, the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear. To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves, we collected conditioned culture medium from hypoxia-pretreated neural crest cells, and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation. The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells. We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells. Subsequently, to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons, we used a microfluidic axonal dissociation model of sensory neurons in vitro, and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons, which was greatly dependent on loaded miR-21-5p. Finally, we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb, as well as muscle tissue morphology of the hind limbs, were obviously restored. These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p. miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome. This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves, and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.

Tailoring photobiomodulation to enhance tissue regeneration

Photobiomodulation (PBM), the use of biocompatible tissue-penetrating light to interact with intracellular chromophores to modulate the fates of cells and tissues, has emerged as a promising non-invasive approach to enhancing tissue regeneration. Unlike photodynamic or photothermal therapies that require the use of photothermal agents or photosensitizers, PBM treatment does not need external agents. With its non-harmful nature, PBM has demonstrated efficacy in enhancing molecular secretions and cellular functions relevant to tissue regeneration. The utilization of low-level light from various sources in PBM targets cytochrome c oxidase, leading to increased synthesis of adenosine triphosphate, induction of growth factor secretion, activation of signaling pathways, and promotion of direct or indirect gene expression. When integrated with stem cell populations, bioactive molecules or nanoparticles, or biomaterial scaffolds, PBM proves effective in significantly improving tissue regeneration. This review consolidates findings from in vitro, in vivo, and human clinical outcomes of both PBM alone and PBM-combined therapies in tissue regeneration applications. It encompasses the background of PBM invention, optimization of PBM parameters (such as wavelength, irradiation, and exposure time), and understanding of the mechanisms for PBM to enhance tissue regeneration. The comprehensive exploration concludes with insights into future directions and perspectives for the tissue regeneration applications of PBM.

Adipose-derived mesenchymal stromal cells in clinical trials: Insights from single-cell studies

Mesenchymal Stromal Cells (MSCs) offer tremendous potential for the treatment of various diseases and their healing properties have been explored in hundreds of clinical trials. These trails primarily focus on immunological and neurological disorders, as well as regenerative medicine. Adipose tissue is a rich source of mesenchymal stromal cells and methods to obtain and culture adipose-derived MSCs (AD-MSCs) have been well established. Promising results from pre-clinical testing of AD-MSCs activity prompted clinical trials that further led to the approval of AD-MSCs for the treatment of complex perianal fistulas in Crohn's disease and subcutaneous tissue defects. However, AD-MSC heterogeneity along with various manufacturing protocols or different strategies to boost their activity create the need for standardized quality control procedures and safety assessment of the intended cell product. High-resolution transcriptomic methods have been recently gaining attention, as they deliver insight into gene expression profiles of individual cells, helping to deconstruct cellular hierarchy and differentiation trajectories, and to understand cell-cell interactions within tissues. This article presents a comprehensive overview of completed clinical trials evaluating the safety and efficacy of AD-MSC treatment, together with current single-cell studies of human AD-MSC. Furthermore, our work emphasizes the increasing significance of single-cell research in elucidating the mechanisms of cellular action and predicting their therapeutic effects.

Mesenchymal stem cells biological and biotechnological advances: Implications for clinical applications

BACKGROUND

Mesenchymal stem cells (MSCs) are multipotent stem cells that are able to differentiate into multiple lineages including bone, cartilage, muscle and fat. They hold immunomodulatory properties and therapeutic ability to treat multiple diseases, including autoimmune and chronic degenerative diseases. In this article, we reviewed the different biological properties, applications and clinical trials of MSCs. Also, we discussed the basics of manufacturing conditions, quality control, and challenges facing MSCs in the clinical setting.

METHODS

Extensive review of the literature was conducted through the databases PubMed, Google Scholar, and Cochrane. Papers published since 2015 and covering the clinical applications and research of MSC therapy were considered. Furthermore, older papers were considered when referring to pioneering studies in the field.

RESULTS

The most widely studied stem cells in cell therapy and tissue repair are bone marrow-derived mesenchymal stem cells. Adipose tissue-derived stem cells became more common and to a lesser extent other stem cell sources e.g., foreskin derived MSCs. MSCs therapy were also studied in the setting of COVID-19 infections, ischemic strokes, autoimmune diseases, tumor development and graft rejection. Multiple obstacles, still face the standardization and optimization of MSC therapy such as the survival and the immunophenotype and the efficiency of transplanted cells. MSCs used in clinical settings displayed heterogeneity in their function despite their extraction from healthy donors and expression of similar surface markers.

CONCLUSION

Mesenchymal stem cells offer a rising therapeutic promise in various diseases. However, their potential use in clinical applications requires further investigation.

Red blood cells based nanotheranostics: A smart biomimetic approach for fighting against cancer

The technique of engineering drug delivery vehicles continues to develop, which bring enhancements in working more efficiently and minimizing side effects to make it more effective and safer. The intense capability of therapeutic agents to remain undamaged in a harsh extracellular environment is helpful to the success of drug development efforts. With this in mind, alterations of biopharmaceuticals with enhanced stability and decreased immunogenicity have been an increasingly active focus of such efforts. Red blood cells (RBCs), also known as erythrocytes have undergone extensive scrutiny as potential vehicles for drug delivery due to their remarkable attributes over the years of research. These include intrinsic biocompatibility, minimal immunogenicity, flexibility, and prolonged systemic circulation. Throughout the course of investigation, a diverse array of drug delivery platforms based on RBCs has emerged. These encompass genetically engineered RBCs, non-genetically modified RBCs, and RBC membrane-coated nanoparticles, each devised to cater to a range of biomedical objectives. Given their prevalence in the circulatory system, RBCs have gained significant attention for their potential to serve as biomimetic coatings for artificial nanocarriers. By virtue of their surface emulation capabilities and customizable core materials, nanocarriers mimicking these RBCs, hold considerable promise across a spectrum of applications, spanning drug delivery, imaging, phototherapy, immunomodulation, sensing, and detection. These multifaceted functionalities underscore the considerable therapeutic and diagnostic potential across various diseases. Our proposed review provides the synthesis of recent strides in the theranostic utilization of erythrocytes in the context of cancer. It also delves into the principal challenges and prospects intrinsic to this realm of research. The focal point of this review pertains to accentuating the significance of erythrocyte-based theranostic systems in combating cancer. Furthermore, it precisely records the latest and the most specific methodologies for tailoring the attributes of these biomimetic nanoscale formulations, attenuating various discoveries for the treatment and management of cancer.

Research progress and prospects of benefit-risk assessment methods for umbilical cord mesenchymal stem cell transplantation in the clinical treatment of spinal cord injury

Over the past decade, we have witnessed the development of cell transplantation as a new strategy for repairing spinal cord injury (SCI). However, due to the complexity of the central nervous system (CNS), achieving successful clinical translation remains a significant challenge. Human umbilical cord mesenchymal stem cells (hUMSCs) possess distinct advantages, such as easy collection, lack of ethical concerns, high self-renewal ability, multilineage differentiation potential, and immunomodulatory properties. hUMSCs are promising for regenerating the injured spinal cord to a significant extent. At the same time, for advancing SCI treatment, the appropriate benefit and risk evaluation methods play a pivotal role in determining the clinical applicability of treatment plans. Hence, this study discusses the advantages and risks of hUMSCs in SCI treatment across four dimensions-comprehensive evaluation of motor and sensory function, imaging, electrophysiology, and autonomic nervous system (ANS) function-aiming to improve the rationality of relevant clinical research and the feasibility of clinical translation.

Encapsulated Mesenchymal Stromal Cells as Cyclic Providers of Immunomodulatory Secretomes: A Living on-Demand Delivery System

The stimulation of mesenchymal stromal cells (MSCs) with inflammatory molecules is often used to boost their therapeutic effect. Prolonged exposure to inflammatory molecules has been explored to improve their action because MSCs therapies seem to be improved transiently with such stimuli. However, the possibility of cyclically stimulating MSCs to recover their optimized therapeutic potential is still to be elucidated, although the efficacy of cell-based therapies may be dependent on the ability to readapt to the relapse pathological conditions. Here, the response of MSCs, encapsulated in alginate hydrogels and cultured for 22 d, is explored using three different regimes: single, continuous, and intermittent stimulation with IFNγ. Exposure to IFNγ leads to a decrease in the secretion of IL-10, which is cyclically countered by IFNγ weaning. Conditioned media collected at different stages of pulsatile stimulation show an immunomodulatory potential toward macrophages, which directly correlates with IL-10 concentration in media. To understand whether the correlation between cyclic stimulation of MSCs and other biological actions can be observed, the effect on endothelial cells is studied, showcasing an overall modest influence on tube formation. Overall, the results describe the response of encapsulated MSCs to unusual pulsatile simulation regimens, exploring encapsulated MSCs as a living on-demand release system of tailored secretomes with recoverable immunomodulatory action.

Gelatin methacryloyl microneedle loaded with 3D-MSC-Exosomes for the protection of ischemia-reperfusion

Exosomes (Exo) generated from mesenchymal stem cells (MSCs) have great therapeutic potential in ischemia-reperfusion treatment. For best therapeutic effect, high quality Exo product and effective delivery system are indispensable. In this study, we developed a new strategy for ischemia-reperfusion recovery by combining MSCs 3D (3D-MSC) culturing technology to generate Exo (3D-MSC-Exo) and microneedle for topical delivery. Firstly, primary MSCs from neonatal mice were isolated and 3D cultured with gelatin methacryloyl (GelMA) hydrogel to prepare 3D-MSC-Exo. The 3D-MSC showed better viability and 3D-MSC-Exo exhibited more effective effects of reducing neuroinflammation, inhibiting glial scarring, and promoting angiogenesis. Subsequently, the biocompatible GelMA was used to construct microneedles for 3D-Exo delivery (GelMA-MN@3D-Exo). The results demonstrated GelMA microneedles had excellent 3D-Exo loading capacity and enabled continuous 3D-Exo release to maintain effective therapeutic concentrations. Furthermore, the rat middle cerebral artery occlusion (MCAO) model was established to evaluate the therapeutic effect of GelMA-MN@3D-Exo in ischemia-reperfusion in vivo. Animal experiments showed that the GelMA-MN@3D-Exo system could effectively reduce the local neuroinflammatory reaction, promote angiogenesis and minimize glial scar proliferation in ischemia-reperfusion. The underlying reasons for the stronger neuroprotective effect of 3D-Exo was further studied using mass spectrometry and transcriptome assays, verifying their effects on immune regulation and cell proliferation. Taken together, our findings demonstrated that GelMA-MN@3D-Exo microneedle can effectively attenuate ischemia-reperfusion cell damage in the MCAO model, which provides a promising therapeutic strategy for ischemia-reperfusion recovery.

Establishing stable and highly osteogenic hiPSC-derived MSCs for 3D-printed bone graft through microenvironment modulation by CHIR99021-treated osteocytes

Human induced pluripotent stem cell (hiPSC)-derived mesenchymal stem cells (iMSCs) are ideal candidates for the production of standardised and scalable bioengineered bone grafts. However, stable induction and osteogenic differentiation of iMSCs pose challenges in the industry. We developed a precise differentiation method to produce homogeneous and fully differentiated iMSCs. In this study, we established a standardised system to prepare iMSCs with increased osteogenic potential and improved bioactivity by introducing a CHIR99021 (C91)-treated osteogenic microenvironment (COOME). COOME enhances the osteogenic differentiation and mineralisation of iMSCs via canonical Wnt signalling. Global transcriptome analysis and co-culturing experiments indicated that COOME increased the pro-angiogenesis/neurogenesis activity of iMSCs. The superior osteogenic differentiation and mineralisation abilities of COOME-treated iMSCs were also confirmed in a Bio3D module generated using a polycaprolactone (PCL) and cell-integrated 3D printing (PCI3D) system, which is the closest model to in vivo research. This COOME-treated iMSCs differentiation system offers a new perspective for generating highly osteogenic, bioactive, and anatomically matched grafts for clinical applications.

Statement of significance

Although human induced pluripotent stem cell-derived MSCs (iMSCs) are ideal seed cells for synthetic bone implants, the challenges of stable induction and osteogenic differentiation hinder their clinical application. This study established a standardised system for the scalable preparation of iMSCs with improved osteogenic potential by combining our precise iMSC differentiation method with the CHIR99021 (C91)-treated osteocyte osteogenic microenvironment (COOME) through the activation of canonical Wnt signalling. Moreover, COOME upregulated the pro-angiogenic and pro-neurogenic capacities of iMSCs, which are crucial for the integration of implanted bone grafts. The superior osteogenic ability of COOME-treated iMSCs was confirmed in Bio3D modules generated using PCL and cell-integrated 3D printing systems, highlighting their functional potential in vivo. This study contributes to tissue engineering by providing insights into the functional differentiation of iMSCs for bone regeneration.

Exosomes from adipose-derived stem cells activate sebocytes through the PI3K/AKT/SREBP-1 pathway to accelerate wound healing

Sebocyte regeneration after injury is considered a key element of functional skin repair. Exosomes from adipose-derived stem cells (ADSCs-EXO) accelerate wound healing by promoting the proliferation of fibroblasts. However, the effects of ADSCs-EXO on sebocytes are largely unknown. In this study, the effects of ADSCs-EXO on sebocyte proliferation and migration were evaluated. The levels of phosphorylated AKT (p-AKT), AKT, sterol regulatory-element binding protein (SREBP), and perilipin-1 (PLIN-1) were detected with immunofluorescence, quantitative PCR, and western blot analysis. RNA-Seq was used to analyze the differential gene expression between the ADSCs-EXO group and the control group under anaerobic conditions. Lipogenesis was assessed with Nile red staining. In animal studies, full-thickness skin wounds in BALB/c mice were treated with gelatin methacrylate (GelMA) hydrogel-loaded sebocytes alone or in combination with ADSCs-EXO. Histopathological assessments of the wound tissues were performed Masson Trichrome staining, Immunohistochemical staining and so on. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway blocker LY294002 inhibited the effects of ADSCs-EXO on p-AKT and sebocytes proliferation. ADSCs-EXO also regulated the expression of SREBP-1 and PLIN-1 through the PI3K/AKT pathway in an oxygen level-dependent manner. In BALB/c mice, ADSCs-EXO accelerated sebocyte-assisted wound healing and regeneration. These in vitro and in vivo results supported that ADSCs-EXO can promote the regeneration of fully functional skin after injury through the PI3K/AKT-dependent activation of sebocytes.

A critical overview of challenging roles of medicinal plants in improvement of wound healing technology

PURPOSE

Chronic diseases often hinder the natural healing process, making wound infections a prevalent clinical concern. In severe cases, complications can arise, potentially leading to fatal outcomes. While allopathic treatments offer numerous options for wound repair and management, the enduring popularity of herbal medications may be attributed to their perceived minimal side effects. Hence, this review aims to investigate the potential of herbal remedies in efficiently treating wounds, presenting a promising alternative for consideration.

METHODS

A literature search was done including research, reviews, systematic literature review, meta-analysis, and clinical trials considered. Search engines such as Pubmed, Google Scholar, and Scopus were used while retrieving data. Keywords like Wound healing 'Wound healing and herbal combinations', 'Herbal wound dressing', Nanotechnology and Wound dressing were used.

RESULT

This review provides valuable insights into the role of natural products and technology-based formulations in the treatment of wound infections. It evaluates the use of herbal remedies as an effective approach. Various active principles from herbs, categorized as flavonoids, glycosides, saponins, and phenolic compounds, have shown effectiveness in promoting wound closure. A multitude of herbal remedies have demonstrated significant efficacy in wound management, offering an additional avenue for care. The review encompasses a total of 72 studies, involving 127 distinct herbs (excluding any common herbs shared between studies), primarily belonging to the families Asteraceae, Fabaceae, and Apiaceae. In research, rat models were predominantly utilized to assess wound healing activities. Furthermore, advancements in herbal-based formulations using nanotechnology-based wound dressing materials, such as nanofibers, nanoemulsions, nanofiber mats, polymeric fibers, and hydrogel-based microneedles, are underway. These innovations aim to enhance targeted drug delivery and expedite recovery. Several clinical-based experimental studies have already been documented, evaluating the efficacy of various natural products for wound care and management. This signifies a promising direction in the field of wound treatment.

CONCLUSION

In recent years, scientists have increasingly utilized evidence-based medicine and advanced scientific techniques to validate the efficacy of herbal medicines and delve into the underlying mechanisms of their actions. However, there remains a critical need for further research to thoroughly understand how isolated chemicals extracted from herbs contribute to the healing process of intricate wounds, which may have life-threatening consequences. This ongoing research endeavor holds great promise in not only advancing our understanding but also in the development of innovative formulations that expedite the recovery process.

Mesenchymal stem cells for cartilage regeneration: Insights into molecular mechanism and therapeutic strategies

The use of mesenchymal stem cells (MSCs) in cartilage regeneration has gained significant attention in regenerative medicine. This paper reviews the molecular mechanisms underlying MSC-based cartilage regeneration and explores various therapeutic strategies to enhance the efficacy of MSCs in this context. MSCs exhibit multipotent capabilities and can differentiate into various cell lineages under specific microenvironmental cues. Chondrogenic differentiation, a complex process involving signaling pathways, transcription factors, and growth factors, plays a pivotal role in the successful regeneration of cartilage tissue. The chondrogenic differentiation of MSCs is tightly regulated by growth factors and signaling pathways such as TGF-β, BMP, Wnt/β-catenin, RhoA/ROCK, NOTCH, and IHH (Indian hedgehog). Understanding the intricate balance between these pathways is crucial for directing lineage-specific differentiation and preventing undesirable chondrocyte hypertrophy. Additionally, paracrine effects of MSCs, mediated by the secretion of bioactive factors, contribute significantly to immunomodulation, recruitment of endogenous stem cells, and maintenance of chondrocyte phenotype. Pre-treatment strategies utilized to potentiate MSCs, such as hypoxic conditions, low-intensity ultrasound, kartogenin treatment, and gene editing, are also discussed for their potential to enhance MSC survival, differentiation, and paracrine effects. In conclusion, this paper provides a comprehensive overview of the molecular mechanisms involved in MSC-based cartilage regeneration and outlines promising therapeutic strategies. The insights presented contribute to the ongoing efforts in optimizing MSC-based therapies for effective cartilage repair.

The comparative effects of bone marrow mesenchymal stem cells and supernatant transplantation on demyelination and inflammation in cuprizone model

BACKGROUND

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) with inflammation and immune dysfunction.

OBJECTIVES

We compared the remyelination and immunomodulation properties of mesenchymal stem cells (MSCs) with their conditioned medium (CM) in the cuprizone model.

METHODS

Twenty-four C57BL/ 6 mice were divided into four groups. After cuprizone demyelination, MSCs and their CM were injected into the right lateral ventricle of mice. The expression level of IL-1β, TNF-α, and BDNF genes was evaluated using the qRT-PCR. APC antibody was used to assess the oligodendrocyte population using the immunofluorescent method. The remyelination and axonal repair were studied by specific staining of the LFB and electron microscopy techniques.

RESULTS

Transplantation of MSCs and CM increased the expression of the BDNF gene and decreased the expression of IL-1β and TNF-α genes compared to the cuprizone group, and these effects in the cell group were more than CM. Furthermore, cell transplantation resulted in a significant improvement in myelination and axonal repair, which was measured by luxol fast blue and transmission electron microscope images. The cell group had a higher number of oligodendrocytes than other groups.

CONCLUSIONS

According to the findings, injecting MSCs intraventricularly versus cell-conditioned medium can be a more effective approach to improving chronic demyelination in degenerative diseases like MS.

Exosomal YB-1 facilitates ovarian restoration by MALAT1/miR-211-5p/FOXO3 axis

Premature ovarian failure (POF) affects many adult women less than 40 years of age and leads to infertility. Mesenchymal stem cells-derived small extracellular vesicles (MSCs-sEVs) are attractive candidates for ovarian function restoration and folliculogenesis for POF due to their safety and efficacy, however, the key mediator in MSCs-sEVs that modulates this response and underlying mechanisms remains elusive. Herein, we reported that YB-1 protein was markedly downregulated in vitro and in vivo models of POF induced with H2O2 and CTX respectively, accompanied by granulosa cells (GCs) senescence phenotype. Notably, BMSCs-sEVs transplantation upregulated YB-1, attenuated oxidative damage-induced cellular senescence in GCs, and significantly improved the ovarian function of POF rats, but that was reversed by YB-1 depletion. Moreover, YB-1 showed an obvious decline in serum and GCs in POF patients. Mechanistically, YB-1 as an RNA-binding protein (RBP) physically interacted with a long non-coding RNA, MALAT1, and increased its stability, further, MALAT1 acted as a competing endogenous RNA (ceRNA) to elevate FOXO3 levels by sequestering miR-211-5p to prevent its degradation, leading to repair of ovarian function. In summary, we demonstrated that BMSCs-sEVs improve ovarian function by releasing YB-1, which mediates MALAT1/miR-211-5p/FOXO3 axis regulation, providing a possible therapeutic target for patients with POF.

A comprehensive review on the role of mesenchymal stromal/stem cells in the management of rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease with systemic manifestations. Although the success of immune modulatory drug therapy is considerable, about 40% of patients do not respond to treatment. Mesenchymal stromal/stem cells (MSCs) have been demonstrated to have therapeutic potential for inflammatory diseases.

AREAS COVERED

This review provides an update on RA disease and on pre-clinical and clinical studies using MSCs from bone marrow, umbilical cord, adipose tissue, and dental pulp, to regulate the immune response. Moreover, the clinical use, safety, limitations, and future perspective of MSCs in RA are discussed. Using the PubMed database and ClincalTrials.gov, peer-reviewed full-text papers, abstracts and clinical trials were identified from 1985 through to April 2023.

EXPERT OPINION

MSCs demonstrated a satisfactory safety profile and potential for clinical efficacy. However, it is mandatory to deepen the investigations on how MSCs affect the proinflammatory deregulated RA patients' cells. MSCs are potentially good candidates for severe RA patients not responding to conventional therapies but a long-term follow-up after stem cells treatment and standardized protocols are needed. Future research should focus on well-designed multicenter randomized clinical trials with adequate sample sizes and properly selected patients satisfying RA criteria for a valid efficacy evaluation.

The secretome from human-derived mesenchymal stem cells augments the activity of antitumor plant extracts in vitro

Cancer is understood as a multifactorial disease that involve multiple cell types and phenotypes in the tumor microenvironment (TME). The components of the TME can interact directly or via soluble factors (cytokines, chemokines, growth factors, extracellular vesicles, etc.). Among the cells composing the TME, mesenchymal stem cells (MSCs) appear as a population with debated properties since it has been seen that they can both promote or attenuate tumor progression. For various authors, the main mechanism of interaction of MSCs is through their secretome, the set of molecules secreted into the extracellular milieu, recruiting, and influencing the behavior of other cells in inflammatory environments where they normally reside, such as wounds and tumors. Natural products have been studied as possible cancer treatments, appealing to synergisms between the molecules in their composition; thus, extracts obtained from Petiveria alliacea (Anamu-SC) and Caesalpinia spinosa (P2Et) have been produced and studied previously on different models, showing promising results. The effect of plant extracts on the MSC secretome has been poorly studied, especially in the context of the TME. Here, we studied the effect of Anamu-SC and P2Et extracts in the human adipose-derived MSC (hAMSC)-tumor cell interaction as a TME model. We also investigated the influence of the hAMSC secretome, in combination with these natural products, on tumor cell hallmarks such as viability, clonogenicity, and migration. In addition, hAMSC gene expression and protein synthesis were evaluated for some key factors in tumor progression in the presence of the extracts by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Multiplex, respectively. It was found that the presence of the hAMSC secretome did not affect the cytotoxic or clonogenicity-reducing activities of the natural extracts on cancer cells, and even this secretome can inhibit the migration of these tumor cells, in addition to the fact that the profile of molecules can be modified by natural products. Overall, our findings demonstrate that hAMSC secretome participation in TME interactions can favor the antitumor activities of natural products.

Molecular Changes in Immunological Characteristics of Bone Marrow Multipotent Mesenchymal Stromal Cells in Lymphoid Neoplasia

Immune system and bone marrow stromal cells play an important role in maintaining normal hematopoiesis. Lymphoid neoplasia disturbs not only development of immune cells, but other immune response mechanisms as well. Multipotent mesenchymal stromal cells (MSCs) of the bone marrow are involved in immune response regulation through both intercellular interactions and secretion of various cytokines. In hematological malignancies, the bone marrow stromal microenvironment, including MSCs, is altered. Aim of this study was to describe the differences of MSCs' immunological function in the patients with acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). In ALL, malignant cells arise from the early precursor cells localized in bone marrow, while in DLBCL they arise from more differentiated B-cells. In this study, only the DLBCL patients without bone marrow involvement were included. Growth parameters, surface marker expression, genes of interest expression, and secretion pattern of bone marrow MSCs from the patients with ALL and DLBCL at the onset of the disease and in remission were studied. MSCs from the healthy donors of corresponding ages were used as controls. It has been shown that concentration of MSCs in the bone marrow of the patients with ALL is reduced at the onset of the disease and is restored upon reaching remission; in the patients with DLBCL this parameter does not change. Proliferative capacity of MSCs did not change in the patients with ALL; however, the cells of the DLBCL patients both at the onset and in remission proliferated significantly faster than those from the donors. Expression of the membrane surface markers and expression of the genes important for differentiation, immunological status maintenance, and cytokine secretion differed significantly in the MSCs of the patients from those of the healthy donors and depended on nosology of the disease. Secretomes of the MSCs varied greatly; a number of proteins associated with immune response regulation, differentiation, and maintenance of hematopoietic stem cells were depleted in the secretomes of the cells from the patients. Lymphoid neoplasia leads to dramatic changes in the functional immunological status of MSCs.

The proliferative effects of stem cells from apical papilla-conditioned medium on rat corneal endothelial cells

The cornea, positioned at the forefront of the eye, refracts the light for focusing images on the retina. Damage to this transparent structure can lead to various visual disorders. The corneal endothelial cells (CECs) are crucial for transparency and homeostasis, but lack the ability to reproduce. Significant damage results in structure destruction and vision impairment. While extensive research has aimed at the restoring the corneal endothelial layer, including endothelial proliferation for functional monolayers remains challenging. Our previous studies confirmed the proliferative activity of stem cells from apical papilla-conditioned medium (SCAP-CM) on the retinal pigmented epithelium as a single cell layer. This study investigates how SCAP-CM influences the proliferation and migration of CECs. Our results introduced Matrigel, as a new matrix component for in vitro culture of CECs. Moreover, 60% of SCAP-CM was able to stimulate CEC proliferation as well as migrate to repair wound healing during 24 h. Confluent CECs also expressed specific markers, ATP1a1, ZO-1 and CD56, indicative of CEC characteristics, aligning with the recapitulation of differentiation when forming a homogenous monolayer at the same level of isolated CECs without in vitro culture. These findings suggested that SCAP-CM administration could be useful for future preclinical and clinical applications.

The Effect of Cell Culture Passage on the Efficacy of Mesenchymal Stromal Cells as a Cell Therapy Treatment

Background/Objective: Mesenchymal Stromal Cells (MSCs) have been considered a promising treatment for several diseases, such as cardiac injuries. Many studies have analyzed their functional properties; however, few studies have characterized MSCs through successive culture passages. The main objective of this work was to analyze the phenotype and functionality of MSCs isolated from two different sources in five culture passages to determine if the culture passage might influence the efficacy of MSCs as a cell therapy treatment. Methods: Bone Marrow (BM)-MSCs were harvested from the femur of Wistar rats (n = 17) and Adipose Tissue(AT)-MSCs were isolated from inguinal fat (n = 17). MSCs were cultured for five culture passages, and the immunophenotype was analyzed by flow cytometry, the functionality was characterized by adipogenic, osteogenic, and chondrogenic differentiation assays, and cytokine secretion capacity was determined through the quantification of the Vascular Endothelial Growth-Factor, Fibroblast Growth-Factor2, and Transforming Growth-Factorβ1 in the cell supernatant. The ultrastructure of MSCs was analyzed by transmission electron microscopy. Results: BM-MSCs exhibited typical phenotypes in culture passages two, four, and five, and their differentiation capacity showed an irregular profile throughout the five culture passages analyzed. AT-MSCs showed a normal phenotype and differentiation capacity in all the culture passages. BM- and AT-MSCs did not modify their secretion ability or ultrastructural morphology. Conclusions: Throughout the culture passages, BM-MSCs, but not AT-MSCs, exhibited changes in their functional and phenotypic characteristic that might affect their efficacy as a cell therapy treatment. Therefore, the culture passage selected should be considered for the application of MSCs as a cell therapy treatment.

PAI-1 transfected-conditioned media promotes osteogenic differentiation of hBMSCs

Reconstruction of injured bone remains challenging in the clinic owing to the lack of suitable bone grafts. The utilization of PAI-1 transfected-conditioned media (P-CM) has demonstrated its ability to facilitate the differentiation process of mesenchymal stem cells (MSCs), potentially serving as a crucial mediator in tissue regeneration. This research endeavored to explore the therapeutic potential of P-CM concerning the differentiation of human bone marrow mesenchymal stem cells (hBMSCs). To assess new bone formation, a rat calvaria critical defect model was employed, while in vitro experiments involved the use of the alizarin Red-S mineral induction test. In the rat calvaria critical defect model, P-CM treatment resulted in significan new bone formation. In vitro, P-CM treated hBMSCs displayed robust osteogenesis compared to the control group, as demonstrated by the mineral induction test using alizarin Red-S. P-CM with hydroxyapatite/β-tricalcium phosphate/fibrin gel treatment significantly exhibited new bone formation, and the expression of osteogenic associated markers was enhanced in the P-CM-treated group. In conclusion, results demonstrate that P-CM treatment significantly enhanced the osteogenic differantiation efficiency and new bone formation, thus could be used as an ideal therapeutic biomolecule for constructing bone-specific implants, especially for orthopedic and dental applications.

Rhoa/ROCK, mTOR and Secretome-Based Treatments for Ischemic Stroke: New Perspectives

Ischemic stroke triggers a complex cascade of cellular and molecular events leading to neuronal damage and tissue injury. This review explores the potential therapeutic avenues targeting cellular signaling pathways implicated in stroke pathophysiology. Specifically, it focuses on the articles that highlight the roles of RhoA/ROCK and mTOR signaling pathways in ischemic brain injury and their therapeutic implications. The RhoA/ROCK pathway modulates various cellular processes, including cytoskeletal dynamics and inflammation, while mTOR signaling regulates cell growth, proliferation, and autophagy. Preclinical studies have demonstrated the neuroprotective effects of targeting these pathways in stroke models, offering insights into potential treatment strategies. However, challenges such as off-target effects and the need for tissue-specific targeting remain. Furthermore, emerging evidence suggests the therapeutic potential of MSC secretome in stroke treatment, highlighting the importance of exploring alternative approaches. Future research directions include elucidating the precise mechanisms of action, optimizing treatment protocols, and translating preclinical findings into clinical practice for improved stroke outcomes.

Comparative analysis of effects of conditioned mediums obtained from 2D or 3D cultured mesenchymal stem cells on kidney functions of diabetic rats: Early intervention could potentiate transdifferentiation of parietal epithelial cell into podocyte precursors

AIM

The secretome of mesenchymal stem cells (MSCs) could be a potential therapeutic intervention for diabetes and associated complications like nephropathy. This study aims to evaluate the effects of conditioned mediums (CMs) collected from umbilical cord-derived MSCs incubated under 2-dimensional (2D) or 3D culture conditions on kidney functions of rats with type-I diabetes (T1D).

MAIN METHODS

Sprague-Dawley rats were treated with 20 mg/kg streptozocin for 5 consecutive days to induce T1D, and 12 doses of CMs were applied intraperitoneally for 4 weeks. The therapeutic effects of CMs were comparatively investigated by biochemical, physical, histopathological, and immunohistochemical analysis.

KEY FINDINGS

3D-CM had significantly higher total protein concentration than the 2D-CM Albumin/creatinine ratios of both treatment groups were significantly improved in comparison to diabetes. Light microscopic evaluations showed that glomerular and cortical tubular damages were significantly ameliorated in only the 3D-CM applied group compared to the diabetes group, which were correlated with transmission electron microscopic observations. The nephrin and synaptopodin expressions increased in both treatment groups compared to diabetes. The WT1, Ki-67, and active caspase-3 expressions in glomeruli and parietal layers of the treatment groups suggest that both types of CMs suppress apoptosis and promote possible parietal epithelial cells' (PECs') transdifferentiation towards podocyte precursor cells by switching on WT1 expression in parietal layer rather than inducing new cell proliferation.

SIGNIFICANCE

3D-CM was found to be more effective in improving kidney functions than 2D-CM by ameliorating glomerular damage through the possible mechanism of transdifferentiation of PECs into podocyte precursors and suppressing glomerular apoptosis.

Exosomes Derived from Mesenchymal Stem Cells: Therapeutic Opportunities for Spinal Cord Injury

Spinal cord injury (SCI) is a serious neurological condition comprising primary and secondary injury and causing severe neurological impairments. The effect of the conventional treatment is limited, including supportive therapy and emergency surgery. Exosomes derived from mesenchymal stem cells (MSCs-Exos) were previously reported to exert its potential therapeutic effects on SCI. Compared with mesenchymal stem cells (MSCs) transplantation for SCI, MSC-Exos showed several superiorities. In the present review, we summarized the revealed data of mechanisms underlying MSC-Exos repairing of SCI and discussed the issues of MSC-Exos use. Thus, in this review we summarized the latest studies on MSCs-Exos in the therapy of SCI and discussed whether MSCs-Exos can be applied to SCI and the prospects of transformation application.

Umbilical cord-derived mesenchymal stem cell secretome promotes skin regeneration and rejuvenation: From mechanism to therapeutics

How to effectively repair cutaneous wounds and promote skin rejuvenation has always been a challenging issue for clinical medicine and medical aesthetics. Current conventional medicines exhibit several drawbacks, including limited therapeutic effects, prolonged treatment periods, and high costs. As a novel cell-free therapy, the umbilical cord-derived mesenchymal stem cell (UCMSC) secretome may offer a promising approach for skin regeneration and rejuvenation. The UCMSC secretome is a collection of all proteins secreted by mesenchymal stem cells, including conditioned media, exosomes, and other substances. The UCMSC secretome has numerous abilities to accelerate acute wound healing, including high fibroblast and keratinocyte proliferative activity, pro-angiogenesis, anti-inflammation, anti-fibrosis, and anti-oxidative stress. Its impact on the four stages of wound healing is manifested by inducing the haemostasis phase, inhibiting the inflammation phase, promoting the proliferation phase, and regulating the remodelling phase. Furthermore, it is highly effective in the treatment of chronic wounds, alopecia, aging, and skin homeostasis disturbance. This review focuses on the clinical therapies and application prospects of the UCMSC secretome, encompassing its source, culture, separation, identification, storage, and pretreatment. Additionally, a discussion on the dosage, administration route, efficacy, and biosafety in the clinical situation is presented. This review aims to provide scientific support for the mechanistic investigation and clinical utilisation of the UCMSC secretome in wound healing and skin rejuvenation.

Mesenchymal stem cells alleviate mouse liver fibrosis by inhibiting pathogenic function of intrahepatic B cells

BACKGROUND AND AIMS

The immunomodulatory characteristics of mesenchymal stem cells (MSCs) make them a promising therapeutic approach for liver fibrosis (LF). Here, we postulated that MSCs could potentially suppress the pro-fibrotic activity of intrahepatic B cells, thereby inhibiting LF progression.

APPROACH AND RESULTS

Administration of MSCs significantly ameliorated LF as indicated by reduced myofibroblast activation, collagen deposition, and inflammation. The treatment efficacy of MSCs can be attributed to decreased infiltration, activation, and pro-inflammatory cytokine production of intrahepatic B cells. Single-cell RNA sequencing revealed a distinct intrahepatic B cell atlas, and a subtype of naive B cells (B-II) was identified, which were markedly abundant in fibrotic liver, displaying mature features with elevated expression of several proliferative and inflammatory genes. Transcriptional profiling of total B cells revealed that intrahepatic B cells displayed activation, proliferation, and pro-inflammatory gene profile during LF. Fibrosis was attenuated in mice ablated with B cells (μMT) or in vivo treatment with anti-CD20. Moreover, fibrosis was recapitulated in μMT after adoptive transfer of B cells, which in turn could be rescued by MSC injection, validating the pathogenic function of B cells and the efficacy of MSCs on B cell-promoted LF progression. Mechanistically, MSCs could inhibit the proliferation and cytokine production of intrahepatic B cells through exosomes, regulating the Mitogen-activated protein kinase and Nuclear factor kappa B signaling pathways.

CONCLUSIONS

Intrahepatic B cells serve as a target of MSCs, play an important role in the process of MSC-induced amelioration of LF, and may provide new clues for revealing the novel mechanisms of MSC action.

Etanercept-synthesizing adipose-derived stem cell secretome: A promising therapeutic option for inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract, with tumor necrosis factor (TNF)-α playing a key role in its pathogenesis. Etanercept, a decoy receptor for TNF, is used to treat inflammatory conditions. The secretome derived from adipose-derived stem cells (ASCs) has anti-inflammatory effects, making it a promising therapeutic option for IBD.

AIM

To investigate the anti-inflammatory effects of the secretome obtained from ASCs synthesizing etanercept on colon cells and in a dextran sulfate sodium (DSS)-induced IBD mouse model.

METHODS

ASCs were transfected with etanercept-encoding mini-circle plasmids to create etanercept-producing cells. The secretory material from these cells was then tested for anti-inflammatory effects both in vitro and in a DSS-induced IBD mouse model.

RESULTS

This study revealed promising results indicating that the group treated with the secretome derived from etanercept-synthesizing ASCs [Etanercept-Secretome (Et-Sec) group] had significantly lower expression levels of inflammatory mediators, such as interleukin-6, Monocyte Chemoattractant Protein-1, and TNF-α, when compared to the control secretome (Ct-Sec). Moreover, the Et-Sec group exhibited a marked therapeutic effect in terms of preserving the architecture of intestinal tissue compared to the Ct-Sec.

CONCLUSION

These results suggest that the secretome derived from ASCs that synthesize etanercept has potential as a therapeutic agent for the treatment of IBD, potentially enhancing treatment efficacy by merging the anti-inflammatory qualities of the ASC secretome with etanercept's targeted approach to better address the multifaceted pathophysiology of IBD.

Nerve Growth Factor-Preconditioned Mesenchymal Stem Cell-Derived Exosome-Functionalized 3D-Printed Hierarchical Porous Scaffolds with Neuro-Promotive Properties for Enhancing Innervated Bone Regeneration

The essential role of the neural network in enhancing bone regeneration has often been overlooked in biomaterial design, leading to delayed or compromised bone healing. Engineered mesenchymal stem cells (MSCs)-derived exosomes are becoming increasingly recognized as potent cell-free agents for manipulating cellular behavior and improving therapeutic effectiveness. Herein, MSCs are stimulated with nerve growth factor (NGF) to regulate exosomal cargoes to improve neuro-promotive potential and facilitate innervated bone regeneration. In vitro cell experiments showed that the NGF-stimulated MSCs-derived exosomes (N-Exos) obviously improved the cellular function and neurotrophic effects of the neural cells, and consequently, the osteogenic potential of the osteo-reparative cells. Bioinformatic analysis by miRNA sequencing and pathway enrichment revealed that the beneficial effects of N-Exos may partly be ascribed to the NGF-elicited multicomponent exosomal miRNAs and the subsequent regulation and activation of the MAPK and PI3K-Akt signaling pathways. On this basis, N-Exos were delivered on the micropores of the 3D-printed hierarchical porous scaffold to accomplish the sustained release profile and extended bioavailability. In a rat model with a distal femoral defect, the N-Exos-functionalized hierarchical porous scaffold significantly induced neurovascular structure formation and innervated bone regeneration. This study provided a feasible strategy to modulate the functional cargoes of MSCs-derived exosomes to acquire desirable neuro-promotive and osteogenic potential. Furthermore, the developed N-Exos-functionalized hierarchical porous scaffold may represent a promising neurovascular-promotive bone reparative scaffold for clinical translation.

Therapeutic potential of mesenchymal stem cell-derived exosomes for allergic airway inflammation

Due to their immunomodulatory capacities, mesenchymal stem cells (MSCs) have been extensively used as therapeutic approaches in cell-based therapy for various inflammatory diseases. Several lines of studies have shown that the most beneficial effects of MSCs are associated with MSC-derived exosomes. Exosomes are nanoscale extracellular vesicles that contain important biomolecules such as RNA, microRNAs (miRNAs), DNA, growth factors, enzymes, chemokines, and cytokines that regulate immune cell functions and parenchymal cell survival. Recently, exosomes, especially MSC-derived exosomes, have been shown to have protective effects in allergic airway inflammation. This review focused on the immune-regulatory potential of MSC-derived exosomes as nanoscale delivery systems in the treatment of allergic airway inflammation.

Human mesenchymal stem cell secretomes: Factors affecting profiling and challenges in clinical application

The promising field of regenerative medicine is thrilling as it can repair and restore organs for various debilitating diseases. Mesenchymal stem cells are one of the main components in regenerative medicine that work through the release of secretomes. By adopting the use of the secretome in cell-free-based therapy, we may be able to address the challenges faced in cell-based therapy. As one of the components of cell-free-based therapy, secretome has the advantage of a better safety and efficacy profile than mesenchymal stem cells. However, secretome has its challenges that need to be addressed, such as its bioprocessing methods that may impact the secretome content and its mechanisms of action in clinical settings. Effective and standardization of bioprocessing protocols are important to ensure the supply and sustainability of secretomes for clinical applications. This may eventually impact its commercialization and marketability. In this review, the bioprocessing methods and their impacts on the secretome profile and treatment are discussed. This improves understanding of its fundamental aspects leading to potential clinical applications.

Application of dental pulp stem cells for bone regeneration

Bone defects resulting from severe trauma, tumors, inflammation, and other factors are increasingly prevalent. Stem cell-based therapies have emerged as a promising alternative. Dental pulp stem cells (DPSCs), sourced from dental pulp, have garnered significant attention owing to their ready accessibility and minimal collection-associated risks. Ongoing investigations into DPSCs have revealed their potential to undergo osteogenic differentiation and their capacity to secrete a diverse array of ontogenetic components, such as extracellular vesicles and cell lysates. This comprehensive review article aims to provide an in-depth analysis of DPSCs and their secretory components, emphasizing extraction techniques and utilization while elucidating the intricate mechanisms governing bone regeneration. Furthermore, we explore the merits and demerits of cell and cell-free therapeutic modalities, as well as discuss the potential prospects, opportunities, and inherent challenges associated with DPSC therapy and cell-free therapies in the context of bone regeneration.

Cytochalasins as Modulators of Stem Cell Differentiation

Regenerative medicine aims to identify new research strategies for the repair and restoration of tissues damaged by pathological or accidental events. Mesenchymal stem cells (MSCs) play a key role in regenerative medicine approaches due to their specific properties, such as the high rate of proliferation, the ability to differentiate into several cell lineages, the immunomodulatory potential, and their easy isolation with minimal ethical issues. One of the main goals of regenerative medicine is to modulate, both in vitro and in vivo, the differentiation potential of MSCs to improve their use in the repair of damaged tissues. Over the years, much evidence has been collected about the ability of cytochalasins, a large family of 60 metabolites isolated mainly from fungi, to modulate multiple properties of stem cells (SCs), such as proliferation, migration, and differentiation, by altering the organization of the cyto- and the nucleo-skeleton. In this review, we discussed the ability of two different cytochalasins, cytochalasins D and B, to influence specific SC differentiation programs modulated by several agents (chemical or physical) or intra- and extra-cellular factors, with particular attention to human MSCs (hMSCs).

Effect of photobiomodulation therapy on the morphology, intracellular calcium concentration, free radical generation, apoptosis and necrosis of human mesenchymal stem cells-an in vitro study

The aim of the study was to investigate the impact of multiwave locked system (MLS M1) emitting synchronized laser radiation at 2 wavelength simultaneous (λ = 808 nm, λ = 905 nm) on the mesenchymal stem cells (MSCs). Human MSCs were exposed to MLS M1 system laser radiation with the power density 195-318 mW/cm2 and doses of energy 3-20 J, in continuous wave emission (CW) or pulsed emission (PE). After irradiation exposure in doses of energy 3 J, 10 J (CW, ƒ = 1000 Hz), and 20 J (ƒ = 2000 Hz), increased proliferation of MSCs was observed. Significant reduction of Fluo-4 Direct™ Ca2+ indicator fluorescence over controls after CW and PE with 3 J, 10 J, and 20 J was noticed. A decrease in fluorescence intensity after the application of radiation with a frequency of 2000 Hz in doses of 3 J, 10 J, and 20 J was observed. In contrary, an increase in DCF fluorescence intensity after irradiation with laser radiation of 3 J, 10 J, and 20 J (CW, ƒ = 1000 Hz and ƒ = 2000 Hz) was also shown. Laser irradiation at a dose of 20 J, emitted at 1000 Hz and 2000 Hz, and 3 J emitted at a frequency of 2000 Hz caused a statistically significant loss of MSC viability. The applied photobiomodulation therapy induced a strong pro-apoptotic effect dependent on the laser irradiation exposure time, while the application of a sufficiently high-energy dose and frequency with a sufficiently long exposure time significantly increased intracellular calcium ion concentration and free radical production by MSCs.

Chitosan Hydrogel Dressing Loaded with Adipose Mesenchymal Stem Cell-Derived Exosomes Promotes Skin Full-Thickness Wound Repair

Cutaneous trauma repair is still a challenge in the clinic due to the scar formation and slow healing rate, especially for diabetic patients. Various drug-loading wound dressings have been explored to solve this problem. Mesenchymal stem cell (MSC)-derived exosomes have been considered as a potential cell-free drug because of their anti-inflammation function and tissue repair property that are comparable to that of MSCs. Herein, a composite wound dressing (Exo/Gel) consisting of the chitosan hydrogel and adipose MSC-derived exosome (ADMSC-Exo) was designed and fabricated by a physical mixing method to promote the skin full-thickness wound repair. The exosomes were slowly released from the Exo/Gel dressing with the degradation of the chitosan hydrogel. The Exo/Gel displayed enhanced cell migration and angiogenic properties in vitro. And the results in the rat skin wound model showed that the Exo/Gel could promote the regular collagen deposition, angiogenesis, and hair follicle mosaicism regeneration. These results proved that the hydrogel dressing with ADMSCs-derived exosomes can accelerate skin wound healing, which is a strategy for developing wound dressings.

Tumorigenic and tumoricidal properties of exosomes in cancers; a forward look

In recent decades, emerging data have highlighted the critical role of extracellular vesicles (EVs), especially (exosomes) Exos, in the progression and development of several cancer types. These nano-sized vesicles are released by different cell lineages within the cancer niche and maintain a suitable platform for the interchange of various signaling molecules in a paracrine manner. Based on several studies, Exos can transfer oncogenic factors to other cells, and alter the activity of immune cells, and tumor microenvironment, leading to the expansion of tumor cells and metastasis to the remote sites. It has been indicated that the cell-to-cell crosstalk is so complicated and a wide array of factors are involved in this process. How and by which mechanisms Exos can regulate the behavior of tumor cells and non-cancer cells is at the center of debate. Here, we scrutinize the molecular mechanisms involved in the oncogenic behavior of Exos released by different cell lineages of tumor parenchyma. Besides, tumoricidal properties of Exos from various stem cell (SC) types are discussed in detail.

Effects of bone marrow mesenchymal stromal cells-derived therapies for experimental traumatic brain injury： A meta-analysis

Background

Bone-marrow-derived mesenchymal stromal (stem) cells [also called MSC(M)] and their extracellular vesicles (EVs) are considered a potentially innovative form of therapy for traumatic brain injury (TBI). Nevertheless, their application to TBI particularly remains preclinical, and the effects of these cells remain unclear and controversial. Therefore, an updated meta-analysis of preclinical studies is necessary to assess the effectiveness of MSC(M) and MSC(M) derived EVs in clinical trials.

Methods

The following databases were searched (to December 2022): PubMed, Web of Science, and Embase. In this study, we measured functional outcomes based on the modified neurological severity score (mNSS), cognitive outcomes based on the Morris water maze (MWM), and histopathological outcomes based on lesion volume. A random effects meta-analysis was conducted to evaluate the effect of mNSS, MWM, and lesion volume.

Results

A total of 2163 unique records were identified from our search, with Fifty-five full-text articles satisfying inclusion criteria. A mean score of 5.75 was assigned to the studies' quality scores, ranging from 4 to 7. MSC(M) and MSC(M) derived EVs had an overall positive effect on the mNSS score and MWM with SMDs -2.57 (95 % CI -3.26; -1.88; p < 0.01) and - 2.98 (95 % CI -4.21; -1.70; p < 0.01), respectively. As well, MSC(M) derived EVs were effective in reducing lesion volume by an SMD of - 0.80 (95 % CI -1.20; -0.40; p < 0.01). It was observed that there was significant variation among the studies, but further analyses could not determine the cause of this heterogeneity.

Conclusions

MSC(M) and MSC(M) derived EVs are promising treatments for TBI in pre-clinical studies, and translation to the clinical domain appears warranted. Besides, large-scale trials in animals and humans are required to support further research due to the limited sample size of MSC(M) derived EVs.

Enhancing regenerative medicine: the crucial role of stem cell therapy

Stem cells offer new therapeutic avenues for the repair and replacement of damaged tissues and organs owing to their self-renewal and multipotent differentiation capabilities. In this paper, we conduct a systematic review of the characteristics of various types of stem cells and offer insights into their potential applications in both cellular and cell-free therapies. In addition, we provide a comprehensive summary of the technical routes of stem cell therapy and discuss in detail current challenges, including safety issues and differentiation control. Although some issues remain, stem cell therapy demonstrates excellent potential in the field of regenerative medicine and provides novel tactics and methodologies for managing a wider spectrum of illnesses and traumas.

Adipose-Derived Stem Cells' Secretome Attenuates Lesion Size and Parasite Loading in Leishmaniasis Caused by Leishmania Major in Mice

Background

Stem cell-derived secretome (SE) released into the extracellular space contributes to tissue repair. The present study aimed to investigate the impact of isolated secretome (SE) from adipose-derived mesenchymal stem cells (ASCs) on Leishmania major (L. major) lesions in BALB/c mice.

Methods

This experimental study was conducted at Ahvaz University of Medical Sciences (Ahvaz, Iran) in 2021. Forty female BALB/c mice were infected with stationary phase promastigotes through intradermal injection in the bottom of their tail and randomly divided into four groups (n=10 per group). The mice were given SE (20 mg/mL), either alone or in combination with Glucantime (GC, 20 mg/mL/Kg), meglumine antimoniate (20 mg/mL/Kg) for the GC group, and phosphate-buffered saline (PBS) for the control group. After eight weeks, the lesion size, histopathology, the levels of Interleukin 10 (IL-10), and Interleukin 12 (IL-12) were assessed. For the comparison of values between groups, the parametric one-way ANOVA was used to assess statistical significance.

Results

At the end of the experiment, the mice that received SE had smaller lesions (4.56±0.83 mm versus 3.62±0.59 mm, P=0.092), lower levels of IL-10 (66.5±9.7 pg/mL versus 285.4±25.2 pg/mL, P<0.001), and higher levels of IL-12 (152.2±14.2 pg/mL versus 24.2±4.4 pg/mL, P<0.001) than the control. Histopathology findings revealed that mice treated with SE had a lower parasite burden in lesions and spleen than the control group.

Conclusion

The current study demonstrated that ADSC-derived SE could protect mice infected with L. major against leishmaniasis.

Therapeutic effect of adipose-derived stem cells injected into pericardial cavity in rat heart failure

AIMS

There are few studies on the treatment of heart failure by injecting stem cells into the pericardial cavity. Can the cells injected into the pericardial cavity migrate through the epicardium to the myocardial tissue? Whether there is therapeutic effect and the mechanism of therapeutic effect are still unclear. This study investigated the therapeutic efficacy and evidence of cell migration of adipose-derived stem cells (ADSCs) injected into the pericardial cavity in rat heart failure. The aim of this study is to demonstrate the effectiveness and mechanism of treating heart failure by injecting stem cells into the pericardial cavity, laying an experimental foundation for a new approach to stem cell therapy for heart disease in clinical practice.

METHODS AND RESULTS

The inguinal adipose tissue of male SD rats aged 4-6 weeks was taken, ADSCs were isolated and cultured, and their stem cell surface markers were identified. Forty rats aged 6-8 weeks were divided into sham operation group, heart failure group, and treatment group; there were 15 rats in the heart failure group and 15 rats in the treatment group. The heart failure model was established by intraperitoneal injection of adriamycin hydrochloride. The heart function of the three groups was detected by small animal ultrasound. The model was successful if the left ventricular ejection fraction < 50%. The identified ADSCs were injected into the pericardial cavity of rats in the treatment group. The retention of transplanted cells in pericardial cavity was detected by small animal in vivo imaging instrument, and the migration of transplanted cells into myocardial tissue was observed by tissue section and immunofluorescence. Western blotting and immunohistochemical staining were used to detect brain natriuretic peptide (BNP), α-smooth muscle actin (α-SMA), and C-reactive protein (CRP). ADSCs express CD29, CD44, and CD73. On the fourth day after injection of ADSCs into pericardial cavity, they migrated to myocardial tissue through epicardium and gradually diffused to deep myocardium. The cell density in the pericardial cavity remains at a high level for 10 days after injection and gradually decreases after 10 days. Compared with the heart failure group, the expression of BNP and α-SMA decreased (P < 0.05 and P < 0.001, respectively), and the expression of CRP in the treatment group was higher than that in the heart failure group (P < 0.0001). A small amount of BNP, α-SMA, and CRP was expressed in the myocardium of the sham operation group. After injection of ADSCs, interleukin-6 in myocardial tissue was significantly lower than that in heart failure myocardium (P < 0.01). After treatment, vascular endothelial growth factor A was significantly higher than that of heart failure (P < 0.01).

CONCLUSIONS

Pericardial cavity injected ADSCs can penetrate the epicardium, migrate into the myocardium, and have a therapeutic effect on heart failure. Their mechanism of action is to exert therapeutic effects through anti-inflammatory, anti-fibrosis, and increased angiogenesis.

Hydrogel Loaded with Components for Therapeutic Applications in Hypertrophic Scars and Keloids

Hypertrophic scars and keloids are common fibroproliferative diseases following injury. Patients with pathologic scars suffer from impaired quality of life and psychological health due to appearance disfiguration, itch, pain, and movement disorders. Recently, the advancement of hydrogels in biomedical fields has brought a variety of novel materials, methods and therapeutic targets for treating hypertrophic scars and keloids, which exhibit broad prospects. This review has summarized current research on hydrogels and loaded components used in preventing and treating hypertrophic scars and keloids. These hydrogels attenuate keloid and hypertrophic scar formation and progression by loading organic chemicals, drugs, or bioactive molecules (such as growth factors, genes, proteins/peptides, and stem cells/exosomes). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favoured by researchers. In addition, combining hydrogels and current therapy (such as laser or radiation therapy, etc.) could improve the treatment of hypertrophic scars and keloids. Then, the difficulties and limitations of the current research and possible suggestions for improvement are listed. Moreover, we also propose novel strategies for facilitating the construction of target multifunctional hydrogels in the future.

Inflammation and Starvation Affect Housekeeping Gene Stability in Adipose Mesenchymal Stromal Cells

Due to the scientific success of in vitro and in vivo model studies, the interest in using mesenchymal stromal cells (MSCs) for the treatment of orthopaedic conditions is growing. In the context of osteoarthritis (OA), MSCs, and, in particular, those derived from adipose tissues (ASCs), have found broader access to clinical use as active components of minimally manipulated orthobiologics, as well as clinically expanded cell preparations, or to collect their released factors (secretome) for cell-free approaches. In this regard, while both inflammatory priming and starvation are common strategies used to empower cell potency or collect the secretome, respectively, little is known about the possible influence of these approaches on the stability of housekeeping genes (HKGs) for molecular studies able to fingerprint cell phenotype or potency. In this report, the reliability of five commonly used HKGs (ACTB, B2M, GAPDH, HPRT1 and RPLP0) was tested in ASCs cultured under standard protocol after inflammatory priming or starvation. Gene expression data were computed with four different applets able to rank genes depending on their stability in either single or combined conditions. The obtained final ranking suggests that for each treatment, a specific HKG is needed, and that starvation is the condition with the stronger effect on HKGs' stability and, therefore, reliability. The normalization effect of proper HKGs' use was then validated on three genes involved in OA and whose product is released by ASCs. Overall, data presented herein confirm that the choice of the best HKG has to be carefully considered and that each specific condition has to be tested to identify the most reliable candidate.

Adipose tissue-derived exosomes alleviate particulate matter-induced inflammatory response and skin barrier damage in atopic dermatitis-like triple-cell model

Recently, particulate matter (PM) has been shown to exacerbate atopic dermatitis (AD) by inducing an inflammatory response. Meanwhile, several studies revealed that exosomes derived from adipose tissue-derived mesenchymal stem cells promote wound healing and alleviate inflammation via their regenerative and immunomodulatory capacities. Our study aimed to investigate the effects of human adipose tissue-derived mesenchymal stem cell-derived (ASC)-exosomes in PM-induced AD. An AD-like triple-cell model was established by treating human keratinocytes, dermal fibroblasts, and mast cells with polyinosinic:polycytidylic acid (Poly I:C) and interleukin 1 alpha (IL-1α). The effects of PM and ASC-exosomes on the expression of pro-inflammatory cytokines and skin barrier proteins were examined using quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. PM increased pro-inflammatory cytokines (IL-6, IL-1β, and IL-1α) and decreased the anti-inflammatory cytokine IL-10, while the mRNA expression of skin barrier proteins (loricrin and filaggrin) decreased. However, when the cells were treated with ASC-exosomes, the PM-induced effects on pro-inflammatory cytokines and skin barrier proteins were reversed. Our results confirmed that PM-induced inflammation and skin barrier damage were alleviated by ASC-exosomes in our AD-like triple-cell model. These data suggest that ASC-exosomes can serve as a therapeutic agent for PM-exacerbated AD.

The Combined Effects on Human Dental Pulp Stem Cells of Fast-Set or Premixed Hydraulic Calcium Silicate Cements and Secretome Regarding Biocompatibility and Osteogenic Differentiation

An important part of regenerative endodontic procedures involving immature permanent teeth is the regeneration of the pulp-dentin complex with continuous root development. Hydraulic calcium silicate cements (HCSCs) are introduced for the pulpal treatment of immature permanent teeth. The stem-cell-derived secretome recently has been applied for the treatment of various damaged tissues. Here, we evaluated the biocompatibility and osteogenic differentiation of HCSCs combined with secretome on human dental pulp stem cells. In the Cell Counting Kit-8 test and wound healing assays, significantly higher cell viability was observed with secretome application. In alkaline phosphatase analysis, the activity was significantly higher with secretome application in all groups, except for RetroMTA on day 2 and Endocem MTA Premixed on day 4. In an Alizarin Red S staining analysis, all groups with secretome application had significantly higher staining values. Quantitative real-time polymerase chain reaction results showed that the day 7 expression of OSX significantly increased with secretome application in all groups. SMAD1 and DSPP expression also increased significantly with secretome addition in all groups except for Biodentine. In conclusion, HCSCs showed favorable biocompatibility and osteogenic ability and are predicted to demonstrate greater synergy with the addition of secretome during regenerative endodontic procedures involving immature permanent teeth.

Investigation of conditioned medium properties obtained from human umbilical cord mesenchymal stem/stromal cells preconditioned with dimethyloxalylglycine in a correlation with ultrastructural changes

Mesenchymal stem/stromal cells (MSCs) hold significant therapeutic value due to their regeneration abilities, migration capacity, and immunosuppressive and immunomodulatory properties. These cells secrete soluble and insoluble factors, and this complex secretome contributes to their therapeutic effect. Furthermore, stimulation of cells by various external stimuli lead to secretome modifications that can increase the therapeutic efficacy. So, this study examined the effect of dimethyloxalylglycine (DMOG), a hypoxia-mimetic agent, on secretome profiles and exosome secretions of MSCs by evaluating conditioned medium (CM) and ultrastructural morphologies of the cells in comparison with unpreconditioned MSCs. The appropriate dose and duration of the use of DMOG were determined as 1000 μM and 24 h by evaluating the HIF-1α expression. DMOG-CM and N-CM were collected from MSCs incubated in serum-free medium with/without DMOG for 24 h, respectively. The content analysis of conditioned mediums (CMs) revealed that VEGF, NGF, and IL-4 levels were increased in DMOG-CM. Subsequently, exosomes were isolated from the CMs and were shown by transmission electron microscopy and Western blot analysis in both groups. The effects of CMs on proliferation and migration were determined by in vitro wound healing tests; both CMs increased the fibroblast's migratory and proliferative capacities. According to the ultrastructural evaluation, autophagosome, autolysosome, myelin figure, and microvesicular body structures were abundant in DMOG-preconditioned MSCs. Consistent with the high number of autophagic vacuoles, Beclin-1 expression was increased in those cells. These findings suggested that DMOG could alter MSCs' secretion profile, modify their ultrastructural morphology accordingly, and make the CM a more potent therapeutic tool. RESEARCH HIGHLIGHTS: Preconditioning mesenchymal stem/stromal cells with dimethyloxalylglycine, a hypoxia-mimetic agent, could modify cellular metabolism. Hypoxic mechanisms lead to alterations in the ultrastructural characteristics of mesenchymal stromal/stem cells. Preconditioning with dimethyloxalylglycine leads to ultrastructural and metabolic changes of mesenchymal stromal/stem cells along with modifications in their secretome profiles. Preconditioning of mesenchymal stromal/stem cells could render them a more potent therapeutic tool.

Stem cell-derived exosomes for traumatic spinal cord injury: a systematic review and network meta-analysis based on a rat model

BACKGROUND AIMS

Exosome therapy for traumatic spinal cord injury (TSCI) is a current research hotspot, but its therapeutic effect and the best source of stem cells for exosomes are unclear.

METHODS

The Web of Science, PubMed, Embase, Cochrane, and Scopus databases were searched from inception to March 28, 2023. Literature screening, data extraction and risk of bias assessment were performed independently by two investigators.

RESULTS

A total of 40 studies were included for data analysis. The findings of our traditional meta-analysis indicate that exosomes derived from stem cells significantly improve the motor function of TSCI at various time points (1 week: weighted mean difference [WMD] = 1.58, 95% confidence interval [CI] 0.87-2.30] 2 weeks: WMD = 3.12, 95% CI 2.64-3.61; 3 weeks: WMD = 4.44, 95% CI 3.27-5.60; 4 weeks: WMD = 4.54, 95% CI 3.42-5.66). Four kinds of stem cell-derived exosomes have been studied: bone marrow mesenchymal stem cells, adipose mesenchymal stem cells, umbilical cord mesenchymal stem cells and neural stem cells. The results of the network meta-analysis showed that there was no significant statistical difference in the therapeutic effect among the exosomes derived from four kinds of stem cells at different treatment time points. Although exosomes derived from bone marrow mesenchymal stem cells are the current research focus, exosomes derived from neural stem cells have the most therapeutic potential and should become the focus of future attention.

CONCLUSIONS

The exosomes derived from stem cells can significantly improve the motor function of TSCI rats, and the exosomes derived from neural stem cells have the most therapeutic potential. However, the lower evidence quality of animal studies limits the reliability of experimental results, emphasizing the need for more high-quality, direct comparative studies to explore the therapeutic efficacy of exosomes and the best source of stem cells.

Microneedle-Mediated Transdermal Delivery of Genetic Materials, Stem Cells, and Secretome: An Update and Progression

Medical practitioners commonly use oral and parenteral dosage forms to administer drugs to patients. However, these forms have certain drawbacks, particularly concerning patients' comfort and compliance. Transdermal drug delivery presents a promising solution to address these issues. Nevertheless, the stratum corneum, as the outermost skin layer, can impede drug permeation, especially for macromolecules, genetic materials, stem cells, and secretome. Microneedles, a dosage form for transdermal delivery, offer an alternative approach, particularly for biopharmaceutical products. In this review, the authors will examine the latest research on microneedle formulations designed to deliver genetic materials, stem cells, and their derivatives. Numerous studies have explored different types of microneedles and evaluated their ability to deliver these products using preclinical models. Some of these investigations have compared microneedles with conventional dosage forms, demonstrating their significant potential for advancing the development of biotherapeutics in the future.

Spheroid size influences cellular senescence and angiogenic potential of mesenchymal stromal cell-derived soluble factors and extracellular vesicles

Introduction: The secretome of mesenchymal stromal cells (MSCs) serves as an innovative tool employed in the regenerative medicine approach. In this particular context, three-dimensional (3D) culture systems are widely utilized to better replicate in vivo conditions and facilitate prolonged cell maintenance during culture. The use of spheroids enables the preservation of the classical phenotypical characteristics of MSCs. However, the distinct microenvironment within the spheroid may impact the secretome, thereby enhancing the angiogenic properties of adult MSCs that typically possess a reduced angiogenic potential compared to MSCs derived from perinatal tissues due to the hypoxia created in the internal region of the spheroid. Methods: In this study, large spheroids (2,600 cells, ∼300 μm diameter) and small spheroids (1,000 cells, ∼200 μm diameter) were used to examine the role of spheroid diameter in the generation of nutrients and oxygen gradients, cellular senescence, and the angiogenic potential of secreted factors and extracellular vesicles (EVs). Results: In this study, we demonstrate that large spheroids showed increased senescence and a secretome enriched in pro-angiogenic factors, as well as pro-inflammatory and anti-angiogenic cytokines, while small spheroids exhibited decreased senescence and a secretome enriched in pro-angiogenic molecules. We also demonstrated that 3D culture led to a higher secretion of EVs with classical phenotypic characteristics. Soluble factors and EVs from small spheroids exhibited higher angiogenic potential in a human umbilical vein endothelial cell (HUVEC) angiogenic assay. Discussion: These findings highlighted the necessity of choosing the appropriate culture system for obtaining soluble factors and EVs for specific therapeutic applications.

Mesenchymal Stem Cells: Their Role in the Tumor Microenvironment

Mesenchymal stem cells (MSCs) have been seen for years as great candidates for treating different diseases and an alternative to embryonic stem cells due to their differentiation capacity in vitro. More recent research has focused on their ability to modulate the immune response and regeneration at sites associated with inflammation, activities attributable to the release of trophic factors into the extracellular medium, a set of components known as the secretome. It has been possible to demonstrate the presence of these cells within the tumor microenvironment, which is associated with their tropism for sites of inflammation; however, their role here needs to be clarified. In different investigations, the feasibility of using MSCs or their secretome to treat cancer has been sought, with these results being ambiguous. It has been described that MSCs can be activated and present various phenotypes, which could explain the divergence in their action; however, these activation mechanisms and the different phenotypes still need to be well known. This review explores MSCs and their use in regenerative medicine with a targeted approach to cancer. Impact Statement This text addresses the diverging findings on the role of mesenchymal stem cells in the tumor microenvironment and discrepancies on the use of these cells as cancer treatment, separating the direct use of the cells from the use of the secretome. Multiple authors refer equally to the cells and their secretome to conclude on the positive or negative outcome, without taking into consideration how the cells are affected by their surroundings.

Porous gelatin microspheres implanted with adipose mesenchymal stromal cells promote angiogenesis via protein kinase B/endothelial nitric oxide synthase signaling pathway in bladder reconstruction

BACKGROUND AIMS

Cell failure and angiogenesis are the key to bladder wall regeneration. Three-dimensional (3D) culture using porous gelatin microspheres (GMs) as a vehicle promotes stem cell proliferation and improves the paracrine capacity of cells. This study aimed to evaluate the therapeutic potential of GMs constructed from adipose-derived mesenchymal stromal cells (ADSCs) (ADSC-GMs) combined with bladder acellular matrix (BAM) in tissue-engineered bladders.

METHODS

Isolation of ADSCs, flow cytometry, scanning electron microscopy and cell counting kit-8, β-galactosidase and enzyme-linked immunosorbent assays were performed in vitro to compare two-dimensional (2D) and 3D cultures. In the in vivo study, male Sprague-Dawley rats were randomly divided into three groups: the BAM replacement alone (BAM) group, ADSCs grown on BAM in replacement (ADSC) group and ADSC-GMs combined with BAM followed by replacement (ADSC-GM) group. Bladder function assessed by urodynamics after 12 weeks of bladder replacement, and the rats were sacrificed at 4 and 12 weeks for further experiments.

RESULTS

The in vitro results showed that GM culture promoted ADSC proliferation, inhibited apoptosis and delayed senescence compared with those in the 2D culture. In addition, ADSC-GMs increased the secretion of the angiogenic factors vascular endothelial growth factor, platelet-derived growth factor-BB, and basal fibroblast growth factor. In vivo experiments revealed that ADSC-GMs adhered to the BAM for longer than ADSCs. Moreover, ADSC-GMs significantly promoted the regeneration of bladder vessels and smooth muscle, thereby facilitating the recovery of bladder function. The expression of phosphorylated protein kinase B (AKT) and phosphorylated endothelial nitric oxide synthase (eNOS) was significantly greater in the ADSC-GMs group compared with the BAM and ADSCs groups.

CONCLUSIONS

ADSC-GMs increased retention of ADSCs on the BAM, thereby promoting the regeneration and functional recovery of the bladder tissue. ADSC-GMs promoted angiogenesis by activating the AKT/eNOS pathway.

Advanced Progress in the Role of Adipose-Derived Mesenchymal Stromal/Stem Cells in the Application of Central Nervous System Disorders

Currently, adipose-derived mesenchymal stromal/stem cells (ADMSCs) are recognized as a highly promising material for stem cell therapy due to their accessibility and safety. Given the frequently irreversible damage to neural cells associated with CNS disorders, ADMSC-related therapy, which primarily encompasses ADMSC transplantation and injection with exosomes derived from ADMSCs or secretome, has the capability to inhibit inflammatory response and neuronal apoptosis, promote neural regeneration, as well as modulate immune responses, holding potential as a comprehensive approach to treat CNS disorders and improve prognosis. Empirical evidence from both experiments and clinical trials convincingly demonstrates the satisfactory safety and efficacy of ADMSC-related therapies. This review provides a systematic summary of the role of ADMSCs in the treatment of central nervous system (CNS) disorders and explores their therapeutic potential for clinical application. ADMSC-related therapy offers a promising avenue to mitigate damage and enhance neurological function in central nervous system (CNS) disorders. However, further research is necessary to establish the safety and efficacy of clinical ADMSC-based therapy, optimize targeting accuracy, and refine delivery approaches for practical applications.