Mesenchymal Stem Cells as a Cornerstone in a Galaxy of Intercellular Signals: Basis for a New Era of Medicine

Challenges and Pitfalls of Research Designs Involving Magnesium-Based Biomaterials: An Overview

Magnesium-based biomaterials hold remarkable promise for various clinical applications, offering advantages such as reduced stress-shielding and enhanced bone strengthening and vascular remodeling compared to traditional materials. However, ensuring the quality of preclinical research is crucial for the development of these implants. To achieve implant success, an understanding of the cellular responses post-implantation, proper model selection, and good study design are crucial. There are several challenges to reaching a safe and effective translation of laboratory findings into clinical practice. The utilization of Mg-based biomedical devices eliminates the need for biomaterial removal surgery post-healing and mitigates adverse effects associated with permanent biomaterial implantation. However, the high corrosion rate of Mg-based implants poses challenges such as unexpected degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity. The biocompatibility and degradability of materials based on magnesium have been studied by many researchers in vitro; however, evaluations addressing the impact of the material in vivo still need to be improved. Several animal models, including rats, rabbits, dogs, and pigs, have been explored to assess the potential of magnesium-based materials. Moreover, strategies such as alloying and coating have been identified to enhance the degradation rate of magnesium-based materials in vivo to transform these challenges into opportunities. This review aims to explore the utilization of Mg implants across various biomedical applications within cellular (in vitro) and animal (in vivo) models.

Combined effect of pantoprazole and mesenchymal stem cells on experimentally induced gastric ulcer: implication of oxidative stress, inflammation and apoptosis pathways

Gastric ulcer (GU) is one of the most common diseases of the upper gastrointestinal tract that affects millions of people worldwide. This study aimed to investigate the possible alleviating effect of a combined treatment of pantoprazole (PANTO) and adipose tissue-derived mesenchymal stem cells (ADSCs) in comparison with each treatment alone on the healing process of the experimentally induced GU in rats, and to uncover the involved pathways. Rats were divided into five groups: (1) Control, (2) GU, (3) PANTO, (4) ADSCs and (5) ADSCs + PANTO. Markers of oxidative stress, inflammation and apoptosis were assessed. The current data indicated that PANTO-, ADSCs- and ADSCs + PANTO-treated groups showed significant drop (p < 0.05) in serum advanced oxidation protein products (AOPPs) and advanced glycation end products (AGEPs) along with significant elevation (p < 0.05) in serum TAC versus the untreated GU group. Moreover, the treated groups (PANTO, ADSCs and ADSCs + PANTO) displayed significant down-regulation (p < 0.05) in gastric nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), tumor necrosis factor alpha (TNF-α), cyclooxygenase-2 (COX-2), intercellular adhesion molecule-1 (ICAM-1), matrix metallopeptidase 9 (MMP-9) and caspase-3 along with significant up-regulation (p < 0.05) in vascular endothelial growth factor (VEGF) and peroxisome proliferator-activated receptor gamma (PPARγ) genes expression compared to the untreated GU group. Immunohistochemical examination of gastric tissue for transforming growth factor β1 (TGF-β1), epidermal growth factor (EGF) and proliferating cell nuclear antigen (PCNA) showed moderate to mild and weak immune reactions, respectively in the PANTO-, ADSCs- and ADSCs + PANTO-treated rat. Histopathological investigation of gastric tissue revealed moderate to slight histopathological alterations and almost normal histological features of the epithelial cells, gastric mucosal layer, muscularis mucosa and submucosa in PANTO-, ADSCs- and ADSCs + PANTO-treated rats, respectively. Conclusively, the co-treatment with ADSCs and PANTO evidenced sententious physiological protection against GU by suppressing oxidative stress, inhibiting inflammation and reducing apoptosis with consequent acceleration of gastric tissue healing process.

Comparison of different sources of mesenchymal stem cells: focus on inflammatory bowel disease

Inflammatory bowel disease (IBD) poses a significant challenge in modern medicine, with conventional treatments limited by efficacy and associated side effects, necessitating innovative therapeutic approaches. Mesenchymal stem cells (MSC) have emerged as promising candidates for IBD treatment due to their immunomodulatory properties and regenerative potential. This thesis aims to explore and compare various sources of MSC and evaluate their efficacy in treating IBD. This study comprehensively analyses MSC derived from multiple sources, including bone marrow, adipose tissue, umbilical cord, and other potential reservoirs. Core elements of this investigation include assessing differences in cell acquisition, immunomodulatory effects, and differentiation capabilities among these MSC sources, as well as comparing their clinical trial outcomes in IBD patients to their therapeutic efficacy in animal models. Through meticulous evaluation and comparative analysis, this thesis aims to elucidate disparities in the efficacy of different MSC sources for IBD treatment, thereby identifying the most promising therapeutic applications. The findings of this study are intended to advance our understanding of MSC biology and offer valuable insights for selecting the most effective MSC sources for personalized IBD therapy. Ultimately, this research endeavor will optimise therapeutic strategies for managing inflammatory bowel disease through the utilization of MSC.

Mesenchymal Stromal Cells: New Generation Treatment of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract, which has a high recurrence rate and is incurable due to a lack of effective treatment. Mesenchymal stromal cells (MSCs) are a class of pluripotent stem cells that have recently received a lot of attention due to their strong self-renewal ability and immunomodulatory effects, and a large number of experimental and clinical models have confirmed the positive therapeutic effect of MSCs on IBD. In preclinical studies, MSC treatment for IBD relies on MSCs paracrine effects, cell-to-cell contact, and its mediated mitochondrial transfer for immune regulation. It also plays a therapeutic role in restoring the intestinal mucosal barrier through the homing effect, regulation of the intestinal microbiome, and repair of intestinal epithelial cells. In the latest clinical trials, the safety and efficacy of MSCs in the treatment of IBD have been confirmed by transfusion of autologous or allogeneic bone marrow, umbilical cord, and adipose MSCs, as well as their derived extracellular vesicles. However, regarding the stable and effective clinical use of MSCs, several concerns emerge, including the cell sources, clinical management (dose, route and frequency of administration, and pretreatment of MSCs) and adverse reactions. This article comprehensively summarizes the effects and mechanisms of MSCs in the treatment of IBD and its advantages over conventional drugs, as well as the latest clinical trial progress of MSCs in the treatment of IBD. The current challenges and future directions are also discussed. This review would add knowledge into the understanding of IBD treatment by applying MSCs.

Advances in natural and synthetic macromolecules with stem cells and extracellular vesicles for orthopedic disease treatment

Serious orthopedic disorders resulting from myriad diseases and impairments continue to pose a considerable challenge to contemporary clinical care. Owing to its limited regenerative capacity, achieving complete bone tissue regeneration and complete functional restoration has proven challenging with existing treatments. By virtue of cellular regenerative and paracrine pathways, stem cells are extensively utilized in the restoration and regeneration of bone tissue; however, low survival and retention after transplantation severely limit their therapeutic effect. Meanwhile, biomolecule materials provide a delivery platform that improves stem cell survival, increases retention, and enhances therapeutic efficacy. In this review, we present the basic concepts of stem cells and extracellular vesicles from different sources, emphasizing the importance of using appropriate expansion methods and modification strategies. We then review different types of biomolecule materials, focusing on their design strategies. Moreover, we summarize several forms of biomaterial preparation and application strategies as well as current research on biomacromolecule materials loaded with stem cells and extracellular vesicles. Finally, we present the challenges currently impeding their clinical application for the treatment of orthopedic diseases. The article aims to provide researchers with new insights for subsequent investigations.

Hydrogel-based immunoregulation of macrophages for tissue repair and regeneration

The rational design of hydrogel materials to modulate the immune microenvironment has emerged as a pivotal approach in expediting tissue repair and regeneration. Within the immune microenvironment, an array of immune cells exists, with macrophages gaining prominence in the field of tissue repair and regeneration due to their roles in cytokine regulation to promote regeneration, maintain tissue homeostasis, and facilitate repair. Macrophages can be categorized into two types: classically activated M1 (pro-inflammatory) and alternatively activated M2 (anti-inflammatory and pro-repair). By regulating the physical and chemical properties of hydrogels, the phenotypic transformation and cell behavior of macrophages can be effectively controlled, thereby promoting tissue regeneration and repair. A full understanding of the interaction between hydrogels and macrophages can provide new ideas and methods for future tissue engineering and clinical treatment. Therefore, this paper reviews the effects of hydrogel components, hardness, pore size, and surface morphology on cell behaviors such as macrophage proliferation, migration, and phenotypic polarization, and explores the application of hydrogels based on macrophage immune regulation in skin, bone, cartilage, and nerve tissue repair. Finally, the challenges and future prospects of macrophage-based immunomodulatory hydrogels are discussed.

Synergistic effect of human uterine cervical mesenchymal stem cell secretome and paclitaxel on triple negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer and, despite its adverse effects, chemotherapy is the standard systemic treatment option for TNBC. Since, it is of utmost importance to consider the combination of different agents to achieve greater efficacy and curability potential, MSC secretome is a possible innovative alternative.

METHODS

In the present study, we proposed to investigate the anti-tumor effect of the combination of a chemical agent (paclitaxel) with a complex biological product, secretome derived from human Uterine Cervical Stem cells (CM-hUCESC) in TNBC.

RESULTS

The combination of paclitaxel and CM-hUCESC decreased cell proliferation and invasiveness of tumor cells and induced apoptosis in vitro (MDA-MB-231 and/or primary tumor cells). The anti-tumor effect was confirmed in a mouse tumor xenograft model showing that the combination of both products has a significant effect in reducing tumor growth. Also, pre-conditioning hUCESC with a sub-lethal dose of paclitaxel enhances the effect of its secretome and in combination with paclitaxel reduced significantly tumor growth and even allows to diminish the dose of paclitaxel in vivo. This effect is in part due to the action of extracellular vesicles (EVs) derived from CM-hUCESC and soluble factors, such as TIMP-1 and - 2.

CONCLUSIONS

In conclusion, our data demonstrate the synergistic effect of the combination of CM-hUCESC with paclitaxel on TNBC and opens an opportunity to reduce the dose of the chemotherapeutic agents, which may decrease chemotherapy-related toxicity.

Immunomodulatory effects of hydatid antigens on mesenchymal stem cells: gene expression alterations and functional consequences

Background

Cystic echinococcosis, caused by the larval stage of Echinococcus granulosus, remains a global health challenge. Mesenchymal stem cells (MSCs) are renowned for their regenerative and immunomodulatory properties. Given the parasite's mode of establishment, we postulate that MSCs likely play a pivotal role in the interaction between the parasite and the host. This study aims to explore the response of MSCs to antigens derived from Echinococcus granulosus, the etiological agent of hydatid disease, with the hypothesis that exposure to these antigens may alter MSC function and impact the host's immune response to the parasite.

Methods

MSCs were isolated from mouse bone marrow and co-cultured with ESPs, HCF, or pLL antigens. We conducted high-throughput sequencing to examine changes in the MSCs' mRNA expression profile. Additionally, cell cycle, migration, and secretory functions were assessed using various assays, including CCK8, flow cytometry, real-time PCR, Western blot, and ELISA.

Results

Our analysis revealed that hydatid antigens significantly modulate the mRNA expression of genes related to cytokine and chemokine activity, impacting MSC proliferation, migration, and cytokine secretion. Specifically, there was a downregulation of chemokines (MCP-1, CXCL1) and pro-inflammatory cytokines (IL-6, NOS2/NO), alongside an upregulation of anti-inflammatory mediators (COX2/PGE2). Furthermore, all antigens reduced MSC migration, and significant alterations in cellular metabolism-related pathways were observed.

Conclusion

Hydatid disease antigens induce a distinct immunomodulatory response in MSCs, characterized by a shift towards an anti-inflammatory phenotype and reduced cell migration. These changes may contribute to the parasite's ability to evade host defenses and persist within the host, highlighting the complex interplay between MSCs and hydatid disease antigens. This study provides valuable insights into the pathophysiology of hydatid disease and may inform the development of novel therapeutic strategies.

Oral ulcer treatment using human tonsil-derived mesenchymal stem cells encapsulated in trimethyl chitosan hydrogel: an animal model study

BACKGROUND

Oral ulcers are a common side effect of chemotherapy and affect patients' quality of life. While stem cell transplantation is a potential treatment for oral ulcers, its efficacy is limited as the stem cells tend to remain in the affected area for a short time. This study aims to develop a treatment for oral ulcers by using trimethyl chitosan (TMC) hydrogel with human tonsil-derived stem cells (hTMSCs) to increase the therapeutic effect of stem cells and investigate their effectiveness.

METHODS

Animals were divided into four experimental groups: Control, TMC hydrogel, hTMSCs, and hTMSCs loaded in TMC hydrogel (Hydrogel + hTMSCs) (each n = 8). Oral ulcers were chemically induced by anesthetizing the rats followed by injection of dilute acetic acid in the right buccal mucosa. After confirming the presence of oral ulcers in the animals, a single subcutaneous injection of 100 µL of each treatment was applied to the ulcer area. Histological analyses were performed to measure inflammatory cells, oral mucosal thickness, and fibrosis levels. The expression level of inflammatory cytokines was also measured using RT-PCR to gauge therapeutic the effect.

RESULTS

The ulcer size was significantly reduced in the TMC hydrogel + hTMSCs group compared to the control group. The stem cells in the tissue were only observed until Day 3 in the hTMSCs treated group, while the injected stem cells in the TMC Hydrogel + hTMSCs group were still present until day 7. Cytokine analysis related to the inflammatory response in the tissue confirmed that the TMC Hydrogel + hTMSCs treated group demonstrated superior wound healing compared to other experimental groups.

CONCLUSION

This study has shown that the adhesion and viability of current stem cell therapies can be resolved by utilizing a hydrogel prepared with TMC and combining it with hTMSCs. The combined treatment can promote rapid healing of oral cavity wounds by enhancing anti-inflammatory effects and expediting wound healing. Therefore, hTMSC loaded in TMC hydrogel was the most effective wound-healing approach among all four treatment groups prolonging stem cell survival. However, further research is necessary to minimize the initial inflammatory response of biomaterials and assess the safety and long-term effects for potential clinical applications.

Exploration of altered miRNA expression and function in MSC-derived extracellular vesicles in response to hydatid antigen stimulation

Background

Hydatid disease is caused by Echinococcus parasites and can affect various tissues and organs in the body. The disease is characterized by the presence of hydatid cysts, which contain specific antigens that interact with the host's immune system. Mesenchymal stem cells (MSCs) are pluripotent stem cells that can regulate immunity through the secretion of extracellular vesicles (EVs) containing microRNAs (miRNAs).

Methods

In this study, hydatid antigens were isolated from sheep livers and mice peritoneal cavities. MSCs derived from mouse bone marrow were treated with different hydatid antigens, and EVs were isolated and characterized from the conditioned medium of MSCs. Small RNA library construction, miRNA target prediction, and differential expression analysis were conducted to identify differentially expressed miRNAs. Functional enrichment and network construction were performed to explore the biological functions of the target genes. Real-time PCR and Western blotting were used for miRNA and gene expression verification, while ELISA assays quantified TNF, IL-1, IL-6, IL-4, and IL-10 levels in cell supernatants.

Results

The study successfully isolated hydatid antigens and characterized MSC-derived EVs, demonstrating the impact of antigen concentration on MSC viability. Key differentially expressed miRNAs, such as miR-146a and miR-9-5p, were identified, with functional analyses revealing significant pathways like Endocytosis and MAPK signaling associated with these miRNAs' target genes. The miRNA-HUB gene regulatory network identified crucial miRNAs and HUB genes, such as Traf1 and Tnf, indicating roles in immune modulation and osteogenic differentiation. Protein-protein interaction (PPI) network analysis highlighted central HUB genes like Akt1 and Bcl2. ALP activity assays confirmed the influence of antigens on osteogenic differentiation, with reduced ALP activity observed. Expression analysis validated altered miRNA and chemokine expression post-antigen stimulation, with ELISA analysis showing a significant reduction in CXCL1 expression in response to antigen exposure.

Conclusion

This study provides insights into the role of MSC-derived EVs in regulating parasite immunity. The findings suggest that hydatid antigens can modulate the expression of miRNAs in MSC-derived EVs, leading to changes in chemokine expression and osteogenic capacity. These findings contribute to a better understanding of the immunomodulatory mechanisms involved in hydatid disease and provide potential therapeutic targets for the development of new treatment strategies.

Antimicrobial, anti-adhesive, and anti-invasive effects of condition media derived from adipose mesenchymal stem cells against Shigella flexneri

The objective of the current study was to examine the antimicrobial, anti-adhesion, and anti-invasion properties of various concentrations of condition media obtained from adipose mesenchymal stem cells (AD-MSCs CM) against Shigella flexneri (S. flexneri). AD-MSCs characterization and antimicrobial assay were performed using flow cytometry and microdilution by colony counting, respectively. For evaluating adhesion and invasion, Caco-2 cells were infected by S. flexneri at three different multiplicities of infection (MOIs of 1, 10, and 50) and then treated with DMEM medium and AD-MSCs CM. The inhibitory effect of AD-MSCs CM was assessed after 24 and 48 h of treatment by CFU (colony-forming unit) counting. A total of 84, 65, and 56% reduction in the adhesion rate of S. flexneri to Caco-2 cells treated with AD-MSCs CM were observed at MOIs of 1, 10, and 50, respectively. While S. flexneri at MOI:1 had no invasive effect on Caco-2 cells, convincing invasion was detected at MOIs of 10 and 50, showing a significant decrease following treatment with AD-MSCs CM. The current study results open new insights into AD-MSCs CM as a new non-antibiotic therapeutic candidate for S. flexneri infections.

Mesenchymal Stem Cells Attenuates Hirschsprung Disease-Associated Enterocolitis by Reducing M1 Macrophages Infiltration via COX-2 Dependewhant Mechanism

OBJECTIVE AND DESIGN

Hirschsprung disease-associated enterocolitis (HAEC) is a common life-threatening complication of Hirschsprung disease (HSCR). We aimed to investigate the effectiveness, long-term safety and the underlying mechanisms of Mesenchymal stem cells (MSCs) based therapy for HAEC.

MATERIAL OR SUBJECTS

Specimens from HSCR and HAEC patients were used to assess the inflammatory condition. Ednrb knock-out mice was used as HAEC model. MSCs was intraperitoneally transplanted into HAEC mice. The therapy effects, long-term outcome, safety and toxicity and the mechanism of MSCs on the treatment of HAEC were explored in vivo and in vitro.

RESULTS

Intestinal M1 macrophages infiltration and severe inflammation condition were observed in HAEC. After the injection of MSCs, HAEC mice showed significant amelioration of the inflammatory injury and inhibition of M1 macrophages infiltration. The expression levels of pro-inflammatory cytokines (TNF-α and IFN-γ) were decreased and anti-inflammatory cytokines (IL-10 and TGF-β) were increased. In addition, we found that effective MSCs homing to the inflamed colon tissue occurred without long-term toxicity response. However, COX-2 inhibitor could diminish the therapeutic effects of MSCs. Using MSCs and macrophages co-culture system, we identified that MSCs could alleviate HAEC by inhibiting M1 macrophages activation through COX-2-dependent MAPK/ERK signaling pathway.

CONCLUSIONS

MSCs ameliorate HAEC by reducing M1 macrophages polarization via COX-2 mediated MAPK/ERK signaling pathway, thus providing novel insights and potentially promising strategy for the treatment or prevention of HAEC.

Efficacy of adipose-derived mesenchymal stem cell therapy in the treatment of chronic micro- and macrovascular complications of diabetes

Diabetes mellitus is a highly prevalent disease characterized by hyperglycaemia that damages the vascular system, leading to micro- (retinopathy, neuropathy, nephropathy) and macrovascular diseases (cardiovascular disease). There are also secondary complications of diabetes (cardiomyopathy, erectile dysfunction or diabetic foot ulcers). Stem cell-based therapies have become a promising tool targeting diabetes symptoms and its chronic complications. Among all stem cells, adipose-derived mesenchymal stem cells (ADMSCs) are of great importance because of their abundance, non-invasive isolation and no ethical limitations. Characteristics that make ADMSCs good candidates for cell-based therapy are their wide immunomodulatory properties and paracrine activities through the secretion of an array of growth factors, chemokines, cytokines, angiogenic factors and anti-apoptotic molecules. Besides, after transplantation, ADMSCs show great ex vivo expansion capacity and differentiation to other cell types, including insulin-producing cells, cardiomyocytes, chondrocytes, hepatocyte-like cells, neurons, endothelial cells, photoreceptor-like cells, or astrocytes. Preclinical studies have shown that ADMSC-based therapy effectively improved visual acuity, ameliorated polyneuropathy and foot ulceration, arrested the development and progression of diabetic kidney disease, or alleviated the diabetes-induced cardiomyocyte hypertrophy. However, despite the positive results obtained in animal models, there are still several challenges that need to be overcome before the results of preclinical studies can be translated into clinical applications. To date, there are several clinical trials or ongoing trials using ADMSCs in the treatment of diabetic complications, most of them in the treatment of diabetic foot ulcers. This narrative review summarizes the most recent outcomes on the usage of ADMSCs in the treatment of long-term complications of diabetes in both animal models and clinical trials.

The Decellularized Cell-Derived Extracellular Matrix Enhances the Paracrine Function of Human Mesenchymal Stromal/Stem Cells

The mesenchymal stromal/stem cells (MSCs) are known to secrete pleiotropic paracrine factors, contributing to tissue regeneration. This unique ability makes MSCs promising therapeutic tools for many diseases, including even those that were previously untreatable. Thus, the development of preconditioning approaches aimed at enhancing the paracrine function of MSCs attracts great interest. In the present work, we studied how the extracellular matrix, the essential part of the native tissue microenvironment, affects the secretory capacity of MSCs of various origins. The MSC-derived decellularized extracellular matrix (dECM), used as the cell culture substrate, triggered strong upregulation of FGF-2, MMP-1, HGF, GRO-α, GRO-β, CXCL-5, CXCL-6, IL-6, IL-8, G-CSF and MCP-1. Functional in vitro tests revealed that conditioned media derived from MSCs cultured on dECM significantly improved 3T3 fibroblast and HaCaT keratinocyte scratch wound healing, stimulated THP-1 monocyte migration and promoted capillary-like HUVEC-based tube formation compared to conditioned media from MSCs grown on plastic. In addition, we found that FAK inhibition promoted dECM-induced upregulation of paracrine factors, suggesting that this kinase participates in the MSCs' paracrine response to dECM. Together, these findings demonstrate that dECM provides cues that considerably enhance the secretory function of MSCs. Thus, dECM usage as a cell culture substrate alone or in combination with a FAK inhibitor may be viewed as a novel MSC preconditioning technique.

Understanding exosomes: Part 1-Characterization, quantification and isolation techniques

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with a diameter in the range of 30-150 nm. Their use has gained great momentum recently due to their ability to be utilized as diagnostic tools with a vast array of therapeutic applications. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be investigated. This review article first focuses on understanding exosomes, including their cellular origin, biogenesis, function, and characterization. Thereafter, overviews of the quantification methods and isolation techniques are given with discussion over their potential use as novel therapeutics in regenerative medicine.

Age-Related Alterations in Mesenchymal Stem Cell Function: Understanding Mechanisms and Seeking Opportunities to Bypass the Cellular Aging

Undoubtedly, mesenchymal stem cells (MSCs) are the most common cell therapy candidates in clinical research and therapy. They not only exert considerable therapeutic effects to alleviate inflammation and promote regeneration, but also show low-immunogenicity properties, which ensure their safety following allogeneic transplantation. Thanks to the necessity of providing a sufficient number of MSCs to achieve clinically efficient outcomes, prolonged in vitro cultivation is indisputable. However, either following long-term in vitro expansion or aging in elderly individuals, MSCs face cellular senescence. Senescent MSCs undergo an impairment in their function and therapeutic capacities and secrete degenerative factors which negatively affect young MSCs. To this end, designing novel investigations to further elucidate cellular senescence and to pave the way toward finding new strategies to reverse senescence is highly demanded. In this review, we will concisely discuss current progress on the detailed mechanisms of MSC senescence and various inflicted changes following aging in MSC. We will also shed light on the examined strategies underlying monitoring and reversing senescence in MSCs to bypass the comprised therapeutic efficacy of the senescent MSCs.

New era of mesenchymal stem cell-based medicine: basis, challenges and prospects

Stem cells of mesenchymal origin (MSC) arouse special interest due to their regenerative, anti-inflammatory, anti-apoptotic, anti-oxidative stress, antitumor or antimicrobial properties. However, its implementation in the clinic runs into drawbacks of cell therapy (immunological incompatibility, tumor formation, possible transmission of infections, entry into cellular senescence, difficult evaluation of safety, dose and potency; complex storage conditions, high economic cost or impractical clinical use). Considering that the positive effects of MSC are due, to a large extent, to the paracrine effects mediated by the set of substances they secrete (growth factors, cytokines, chemokines or microvesicles), the in vitro obtaining of these biological products makes possible a medicine cell-free regenerative therapy without the drawbacks of cell therapy. However, this new therapeutic innovation implies challenges, such as the recognition of the biological heterogeneity of MSC and the optimization and standardization of their secretome.

Can extracellular vesicles be considered as a potential frontier in the treatment of intervertebral disc disease?

As a global public health problem, low back pain (LBP) caused by intervertebral disc degeneration (IDD) seriously affects patients' quality of life. In addition, the prevalence of IDD tends to be younger, which brings a huge burden to individuals and society economically. Current treatments do not delay or reverse the progression of IDD. The emergence of biologic therapies has brought new hope for the treatment of IDD. Among them, extracellular vesicles (EVs), as nanoscale bioactive substances that mediate cellular communication, have now produced many surprising results in the research of the treatment of IDD. This article reviews the mechanisms and roles of EVs in delaying IDD and describes the prospects and challenges of EVs.

Enhanced Intervertebral Disc Repair via Genetically Engineered Mesenchymal Stem Cells with Tetracycline Regulatory System

The therapeutic potential of Mesenchymal stem cells (MSCs) for the treatment of Intervertebral disc (IVD) degeneration can be enhanced by amplifying specific cytokines and proteins. This study aimed to investigate the therapeutic potential of tetracycline-off system-engineered tonsil-derived mesenchymal stem cells (ToMSC-Tetoff-TGFβ1-IGF1-BMP7) for treating intervertebral disc (IVD) degeneration. ToMSCs were isolated from a tonsillectomy patient and genetically modified with four distinct plasmids via CRISPR/Cas9-mediated knock-in gene editing. Transgene expression was confirmed through immunofluorescence, western blots, and an enzyme-linked immunosorbent assay for transforming growth factor beta 1 (TGFβ1) protein secretion, and the effect of MSC-TetOff-TGFβ1-IGF1-BMP7 on disc injury was assessed in a rat model. The ToMSC-Tetoff-TGFβ1-IGF1-BMP7 treatment exhibited superior therapeutic effects compared to ToMSC-TGFβ1, and ToMSC-SDF1α implantation groups, stimulating the regeneration of nucleus pulposus (NP) cells crucial for IVD. The treatment showed potential to restore the structural integrity of the extracellular matrix (ECM) by upregulating key molecules such as aggrecan and type II collagen. It also exhibited anti-inflammatory properties and reduced pain-inducing neuropeptides. ToMSC-Tetoff-TGFβ1-IGF1-BMP7 holds promise as a novel treatment for IVD degeneration. It appears to promote NP cell regeneration, restore ECM structure, suppress inflammation, and reduce pain. However, more research and clinical trials are required to confirm its therapeutic potential.

Regenerative and translational medicine in COPD: hype and hope

COPD is a common, preventable and usually progressive disease associated with an enhanced chronic inflammatory response in the airways and lung, generally caused by exposure to noxious particles and gases. It is a treatable disease characterised by persistent respiratory symptoms and airflow limitation due to abnormalities in the airways and/or alveoli. COPD is currently the third leading cause of death worldwide, representing a serious public health problem and a high social and economic burden. Despite significant advances, effective clinical treatments have not yet been achieved. In this scenario, cell-based therapies have emerged as potentially promising therapeutic approaches. However, there are only a few published studies of cell-based therapies in human patients with COPD and a small number of ongoing clinical trials registered on clinicaltrials.gov Despite the advances and interesting results, numerous doubts and questions remain about efficacy, mechanisms of action, culture conditions, doses, timing, route of administration and conditions related to homing and engraftment of the infused cells. This article presents the state of the art of cell-based therapy in COPD. Clinical trials that have already been completed and with published results are discussed in detail. We also discuss the questions that remain unanswered about cell-based regenerative and translational medicine for COPD.

Exosome/metformin-loaded self-healing conductive hydrogel rescues microvascular dysfunction and promotes chronic diabetic wound healing by inhibiting mitochondrial fission

Chronic diabetic wounds remain a globally recognized clinical challenge. They occur due to high concentrations of reactive oxygen species and vascular function disorders. A promising strategy for diabetic wound healing is the delivery of exosomes, comprising bioactive dressings. Metformin activates the vascular endothelial growth factor pathway, thereby improving angiogenesis in hyperglycemic states. However, multifunctional hydrogels loaded with drugs and bioactive substances synergistically promote wound repair has been rarely reported, and the mechanism of their combinatorial effect of exosome and metformin in wound healing remains unclear. Here, we engineered dual-loaded hydrogels possessing tissue adhesive, antioxidant, self-healing and electrical conductivity properties, wherein 4-armed SH-PEG cross-links with Ag⁺, which minimizes damage to the loaded goods and investigated their mechanism of promotion effect for wound repair. Multiwalled carbon nanotubes exhibiting good conductivity were also incorporated into the hydrogels to generate hydrogen bonds with the thiol group, creating a stable three-dimensional structure for exosome and metformin loading. The diabetic wound model of the present study suggests that the PEG/Ag/CNT-M + E hydrogel promotes wound healing by triggering cell proliferation and angiogenesis and relieving peritraumatic inflammation and vascular injury. The mechanism of the dual-loaded hydrogel involves reducing the level of reactive oxygen species by interfering with mitochondrial fission, thereby protecting F-actin homeostasis and alleviating microvascular dysfunction. Hence, we propose a drug-bioactive substance combination therapy and provide a potential mechanism for developing vascular function-associated strategies for treating chronic diabetic wounds.

Herpes Simplex Virus Infection Alters the Immunological Properties of Adipose-Tissue-Derived Mesenchymal-Stem Cells

The proper functioning of mesenchymal stem cells (MSCs) is of paramount importance for the homeostasis of the body. Inflammation and infection can alter the function of MSCs, which can also affect the regenerative potential and immunological status of tissues. It is not known whether human herpes simplex viruses 1 and 2 (HSV1 and HSV2), well-known human pathogens that can cause lifelong infections, can induce changes in MSCs. In non-healing ulcers, HSV infection is known to affect deeper tissue layers. In addition, HSV infection can recur after initially successful cell therapies. Our aim was to study the response of adipose-derived MSCs (ADMSCs) to HSV infection in vitro. After confirming the phenotype and differentiation capacity of the isolated cells, we infected the cells in vitro with HSV1-KOS, HSV1-532 and HSV2 virus strains. Twenty-four hours after infection, we examined the gene expression of the cells via RNA-seq and RT-PCR; detected secreted cytokines via protein array; and determined autophagy via Western blot, transmission electron microscopy (TEM) and fluorescence microscopy. Infection with different HSV strains resulted in different gene-expression patterns. In addition to the activation of pathways characteristic of viral infections, distinct non-immunological pathways (autophagy, tissue regeneration and differentiation) were also activated according to analyses with QIAGEN Ingenuity Pathway Analysis, Kyoto Encyclopedia of Genes and Genome and Genome Ontology Enrichment. Viral infections increased autophagy, as confirmed via TEM image analysis, and also increased levels of the microtubule-associated protein light chain 3 (LC3B) II protein. We identified significantly altered accumulation for 16 cytokines involved in tissue regeneration and inflammation. Our studies demonstrated that HSV infection can alter the viability and immunological status of ADMSCs, which may have implications for ADMSC-based cell therapies. Alterations in autophagy can affect numerous processes in MSCs, including the inhibition of tissue regeneration as well as pathological differentiation.

Genomic instability in long-term culture of human adipose-derived mesenchymal stromal cells

Mesenchymal stromal/stem cells stem (MSC) have been widely studied due to their great potential for application in tissue engineering and regenerative and translational medicine. In MSC-based therapy for human diseases, cell proliferation is required to obtain a large and adequate number of cells to ensure therapeutic efficacy. During in vitro culture, cells are under an artificial environment and manipulative stress that can affect genetic stability. Several regulatory agencies have established guidelines to ensure greater safety in cell-based regenerative and translational medicine, but there is no specific definition about the maximum number of passages that ensure the lowest possible risk in MSC-based regenerative medicine. In this context, the aim of this study was to analyze DNA damage and chromosome alterations in adipose-derived mesenchymal stromal cells (ADMSC) until the eleventh passage and to provide additional subsidies to regulatory agencies related to number of passages in these cells. Thus, two methods in genetic toxicology were adopted: comet assay and micronucleus test. The comet assay results showed an increase in DNA damage from the fifth passage onwards. The micronucleus test showed a statistically significant increase of micronucleus from the seventh passage onwards, indicating a possible mutagenic effect associated with the increase in the number of passages. Based on these results, it is important to emphasize the need to assess genetic toxicology and inclusion of new guidelines by regulatory agencies to guarantee the safety of MSC-based therapies for human diseases.

Endogenous Lipid Carriers—Bench-to-Bedside Roadblocks in Production and Drug Loading of Exosomes

Exosomes are cell-derived, nano-sized extracellular vesicles comprising a lipid bilayer membrane that encapsulates several biological components, such as nucleic acids, lipids, and proteins. The role of exosomes in cell–cell communication and cargo transport has made them promising candidates in drug delivery for an array of diseases. Despite several research and review papers describing the salient features of exosomes as nanocarriers for drug delivery, there are no FDA-approved commercial therapeutics based on exosomes. Several fundamental challenges, such as the large-scale production and reproducibility of batches, have hindered the bench-to-bedside translation of exosomes. In fact, compatibility and poor drug loading sabotage the possibility of delivering several drug molecules. This review provides an overview of the challenges and summarizes the potential solutions/approaches to facilitate the clinical development of exosomal nanocarriers.

Remote control of the recruitment and capture of endogenous stem cells by ultrasound for in situ repair of bone defects

Stem cell-based tissue engineering has provided a promising platform for repairing of bone defects. However, the use of exogenous bone marrow mesenchymal stem cells (BMSCs) still faces many challenges such as limited sources and potential risks. It is important to develop new approach to effectively recruit endogenous BMSCs and capture them for in situ bone regeneration. Here, we designed an acoustically responsive scaffold (ARS) and embedded it into SDF-1/BMP-2 loaded hydrogel to obtain biomimetic hydrogel scaffold complexes (BSC). The SDF-1/BMP-2 cytokines can be released on demand from the BSC implanted into the defected bone via pulsed ultrasound (p-US) irradiation at optimized acoustic parameters, recruiting the endogenous BMSCs to the bone defected or BSC site. Accompanied by the daily p-US irradiation for 14 days, the alginate hydrogel was degraded, resulting in the exposure of ARS to these recruited host stem cells. Then another set of sinusoidal continuous wave ultrasound (s-US) irradiation was applied to excite the ARS intrinsic resonance, forming highly localized acoustic field around its surface and generating enhanced acoustic trapping force, by which these recruited endogenous stem cells would be captured on the scaffold, greatly promoting them to adhesively grow for in situ bone tissue regeneration. Our study provides a novel and effective strategy for in situ bone defect repairing through acoustically manipulating endogenous BMSCs.

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We designed ARS and embedded it into SDF-1/BMP-2 loaded hydrogel to form BSC.

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The BSC can release SDF-1/BMP-2 by p-US irradiation for recruitment of endogenous BMSCs and capture them by s-US irradiation.

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The in situ repair of bone defects were successfully realized by US-mediated control of the recruitment and capture of BMSCs.

New Sources, Differentiation, and Therapeutic Uses of Mesenchymal Stem Cells 2.0

For the clinical application of mesenchymal stem cells (MSCs), the optimization of biological products (e [...].

T Cell and Cytokine Dynamics in the Blood of Patients after Hematopoietic Stem Cell Transplantation and Multipotent Mesenchymal Stromal Cell Administration

Multipotent mesenchymal stromal cells (MSCs) are currently under intensive investigation for the treatment and prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), owing to their substantial immunomodulatory properties. The responses of recipients to MSC infusion following allo-HSCT are not yet well understood. T cells are central to the adaptive immune system, protecting the organism from infection and malignant cells. Memory T cells with different phenotypes, gene expression profiles, and functional properties are critical for immune processes regulation. The aim of this study was to study the dynamics of memory T cell subpopulations and cytokines in the blood of allo-HSCT recipients after MSC administration. In clinical trial NCT01941394, patients after allo-HSCT were randomized into 2 groups, one receiving standard GVHD prophylaxis and the other also receiving MSC infusion on the day of leukocyte recovery to 1000 cells/μL (engraftment, day E0). Blood samples of patients from both groups were analyzed on days E0, E+3, and E+30. T cell subpopulations were studied by flow cytometry, and cytokine concentrations were evaluated by the Bio-Plex Pro Human Cytokine Panel. Administration of MSCs to patients on day E0 did not affect the overall dynamics of restoration of absolute numbers and proportions of T and B lymphocytes after 3 and 30 days. At 3 days after MSC injection, only the numbers of CD8⁺ effector cells (CD8⁺_TE, CD8⁺_TM, and CD8⁺_EM) were found to increase significantly. A significant increase in the number of CD4⁺ cells after 30 days compared to day E0 was observed only in patients who received MSCs, indicating faster recovery of the CD4⁺ cell population following MSC injection. An increase in CD8⁺ cell number by day E+30 was significant regardless of MSC administration. To characterize the immune status of patients following allo-HSCT in more detail, changes in the cytokine concentration in the peripheral blood of patients on days E0, E+3, and E+30 after MSC administration were investigated. On day E+30, significant increases in the numbers of CD4⁺_CM and activated CD4⁺CD25⁺ cells were observed. The concentrations of proinflammatory and anti-inflammatory cytokines IL-6, IL-8, IL-17, TNF-α, and IFN-γ were increased significantly in patients injected with MSCs. Analysis of growth factor levels showed that in the group of patients who received MSCs, the concentrations of G-CSF, GM-CSF, PDGFbb, FGFb, and IL-5 increased by day E+30. Among the cytokines involved in regulation of the immune response, concentrations of IL-9, eotaxin, IP-10, MCP-1, and MIP-1a were increased after 30 days irrespective of MSC administration. The administration of MSCs exerts a positive effect on the restoration of T cell subpopulations and immune system recovery in patients after allo-HSCT.

Protective effects of conditioned media of immortalized stem cells from human exfoliated deciduous teeth on pressure ulcer formation

Pressure ulcers (PUs) are increasing with aging worldwide, but there is no effective causal therapy. Although mesenchymal stem cells (MSCs) promote cutaneous wound healing, the effects of the conditioned medium (CM) of MSCs on cutaneous PU formation induced by ischemia-reperfusion injury have been poorly investigated. To address this issue, herein, we first established an immortalized stem cell line from human exfoliated deciduous teeth (SHED). This cell line was revealed to have superior characteristics in that it grows infinitely and vigorously, and stably and consistently secretes a variety of cytokines. Using the CM obtained from the immortalized SHED cell line, we investigated the therapeutic potential on a cutaneous ischemia-reperfusion mouse model for PU formation using two magnetic plates. This is the first study to show that CM from immortalized SHEDs exerts therapeutic effects on PU formation by promoting angiogenesis and oxidative stress resistance through vascular endothelial growth factor and hepatocyte growth factor. Thus, the CM of MSCs has potent therapeutic effects, whereas these therapies have not been implemented in human medicine. To try to meet the regulatory requirements for manufacturing and quality control as much as possible, it is necessary to produce CM that is consistently safe and effective. The immortalization of stem cells could be one of the breakthroughs to meet the regulatory requirements and consequently open up a novel avenue to create a novel type of cell-free regenerative medicine, although further investigation into the quality control is warranted.

Critical roles of cytokine storm and bacterial infection in patients with COVID-19: therapeutic potential of mesenchymal stem cells

The severe acute respiratory syndrome coronavirus 2 has been a shocking disaster for healthcare systems worldwide since December 2019. This virus can affect all systems of the body and its symptoms vary from a simple upper respiratory infection to fatal complications including end-organ damage. On the other hand, the normal immune system plays a pivotal role in the recovery of infectious diseases such as COVID-19. However, occasionally, exaggerated immune system inflammation and an excessive synthesis of cytokines, known as a "cytokine storm," can deteriorate the patient's clinical condition. Secondary bacterial co-infection is another problem in COVID-19 which affects the prognosis of patients. Although there are a few studies about this complication, they suggest not using antibiotics commonly, especially broad-spectrum ones. During this pandemic, various approaches and therapeutics were introduced for treating COVID-19 patients. However, available treatments are not helpful enough, especially for complicated cases. Hence, in this era, cell therapy and regenerative medicine will create new opportunities. Therefore, the therapeutic benefits of mesenchymal stem cells, especially their antimicrobial activity, will help us understand how to treat COVID-19. Herein, mesenchymal stem cells may stop the immune system from becoming overactive in COVID-19 patients. On the other side, the stem cells' capacity for repair could encourage natural healing processes.

Towards a New Concept of Regenerative Endodontics Based on Mesenchymal Stem Cell-Derived Secretomes Products

The teeth, made up of hard and soft tissues, represent complex functioning structures of the oral cavity, which are frequently affected by processes that cause structural damage that can lead to their loss. Currently, replacement therapy such as endodontics or implants, restore structural defects but do not perform any biological function, such as restoring blood and nerve supplies. In the search for alternatives to regenerate the dental pulp, two alternative regenerative endodontic procedures (REP) have been proposed: (I) cell-free REP (based in revascularization and homing induction to remaining dental pulp stem cells (DPSC) and even stem cells from apical papilla (SCAP) and (II) cell-based REP (with exogenous cell transplantation). Regarding the last topic, we show several limitations with these procedures and therefore, we propose a novel regenerative approach in order to revitalize the pulp and thus restore homeostatic functions to the dentin-pulp complex. Due to their multifactorial biological effects, the use of mesenchymal stem cells (MSC)-derived secretome from non-dental sources could be considered as inducers of DPSC and SCAP to completely regenerate the dental pulp. In partial pulp damage, appropriate stimulate DPSC by MSC-derived secretome could contribute to formation and also to restore the vasculature and nerves of the dental pulp.

Isolation and characterization of farm pig adipose tissue-derived mesenchymal stromal/stem cells

Adipose tissue-derived mesenchymal stromal/stem cells (ASCs) are considered important tools in regenerative medicine and are being tested in several clinical studies. Porcine models are frequently used to obtain adipose tissue, due to the abundance of material and because they have immunological and physiological similarities with humans. However, it is essential to understand the effects and safe application of ASCs from pigs (pASCs) as an alternative therapy for diseases. Although minipigs are easy-to-handle animals that require less food and space, acquiring and maintaining them in a bioterium can be costly. Thus, we present a protocol for the isolation and proliferation of ASCs isolated from adipose tissue of farm pigs. Adipose tissue samples were extracted from the abdominal region of the animals. Because the pigs were not raised in a controlled environment, such as a bioterium, it was necessary to carry out rigorous procedures for disinfection. After this procedure, cells were isolated by mechanical dissociation and enzymatic digestion. A proliferation curve was performed and used to calculate the doubling time of the population. The characterization of pASCs was performed by immunophenotyping and cell differentiation in osteogenic and adipogenic lineages. The described method was efficient for the isolation and cultivation of pASCs, maintaining cellular attributes, such as surface antigens and multipotential differentiation during in vitro proliferation. This protocol presents the isolation and cultivation of ASCs from farm pig as an alternative for the isolation and cultivation of ASCs from minipigs, which require strictly controlled maintenance conditions and a more expensive process.

Aging and Mesenchymal Stem Cells: Basic Concepts, Challenges and Strategies

Aging and frailty are complex processes implicating multifactorial mechanisms, such as replicative senescence, oxidative stress, mitochondrial dysfunction, or autophagy disorder. All of these mechanisms drive dramatic changes in the tissue environment, such as senescence-associated secretory phenotype factors and inflamm-aging. Thus, there is a demand for new therapeutic strategies against the devastating effects of the aging and associated diseases. Mesenchymal stem cells (MSC) participate in a "galaxy" of tissue signals (proliferative, anti-inflammatory, and antioxidative stress, and proangiogenic, antitumor, antifibrotic, and antimicrobial effects) contributing to tissue homeostasis. However, MSC are also not immune to aging. Three strategies based on MSC have been proposed: remove, rejuvenate, or replace the senescent MSC. These strategies include the use of senolytic drugs, antioxidant agents and genetic engineering, or transplantation of younger MSC. Nevertheless, these strategies may have the drawback of the adverse effects of prolonged use of the different drugs used or, where appropriate, those of cell therapy. In this review, we propose the new strategy of "Exogenous Restitution of Intercellular Signalling of Stem Cells" (ERISSC). This concept is based on the potential use of secretome from MSC, which are composed of molecules such as growth factors, cytokines, and extracellular vesicles and have the same biological effects as their parent cells. To face this cell-free regenerative therapy challenge, we have to clarify key strategy aspects, such as establishing tools that allow us a more precise diagnosis of aging frailty in order to identify the therapeutic requirements adapted to each case, identify the ideal type of MSC in the context of the functional heterogeneity of these cellular populations, to optimize the mass production and standardization of the primary materials (cells) and their secretome-derived products, to establish the appropriate methods to validate the anti-aging effects and to determine the most appropriate route of administration for each case.

Prostate Cancer Tumor Stroma: Responsibility in Tumor Biology, Diagnosis and Treatment

Simple Summary

The crosstalk between prostate stroma and its epithelium is essential to tissue homeostasis. Likewise, reciprocal signaling between tumor cells and the stromal compartment is required in tumor progression to facilitate or stimulate key processes such as cell proliferation and invasion. The aim of the present work was to review the current state of knowledge on the significance of tumor stroma in the genesis, progression and therapeutic response of prostate carcinoma. Additionally, we addressed the future therapeutic opportunities.

Abstract

Prostate cancer (PCa) is a common cancer among males globally, and its occurrence is growing worldwide. Clinical decisions about the combination of therapies are becoming highly relevant. However, this is a heterogeneous disease, ranging widely in prognosis. Therefore, new approaches are needed based on tumor biology, from which further prognostic assessments can be established and complementary strategies can be identified. The knowledge of both the morphological structure and functional biology of the PCa stroma compartment can provide new diagnostic, prognostic or therapeutic possibilities. In the present review, we analyzed the aspects related to the tumor stromal component (both acellular and cellular) in PCa, their influence on tumor behavior and the therapeutic response and their consideration as a new therapeutic target.

Mesenchymal (Stem) Stromal Cells Based as New Therapeutic Alternative in Inflammatory Bowel Disease: Basic Mechanisms, Experimental and Clinical Evidence, and Challenges

Inflammatory bowel diseases (IBD) are an example of chronic diseases affecting 40% of the population, which involved tissue damage and an inflammatory process not satisfactorily controlled with current therapies. Data suggest that mesenchymal stem cells (MSC) may be a therapeutic option for these processes, and especially for IBD, due to their multifactorial approaches such as anti-inflammatory, anti-oxidative stress, anti-apoptotic, anti-fibrotic, regenerative, angiogenic, anti-tumor, or anti-microbial. However, MSC therapy is associated with important limitations as safety issues, handling difficulties for therapeutic purposes, and high economic cost. MSC-derived secretome products (conditioned medium or extracellular vesicles) are therefore a therapeutic option in IBD as they exhibit similar effects to their parent cells and avoid the issues of cell therapy. In this review, we proposed further studies to choose the ideal tissue source of MSC to treat IBD, the implementation of new standardized production strategies, quality controls and the integration of other technologies, such as hydrogels, which may improve the therapeutic effects of derived-MSC secretome products in IBD.

Mesenchymal Stem Cell-Derived Exosomes and Intervertebral Disc Regeneration: Review

Intervertebral disc degeneration (IVDD) is a common cause of lower back pain (LBP), which burdens individuals and society as a whole. IVDD occurs as a result of aging, mechanical trauma, lifestyle factors, and certain genetic abnormalities, leads to loss of nucleus pulposus, alteration in the composition of the extracellular matrix, excessive oxidative stress, and inflammation in the intervertebral disc. Pharmacological and surgical interventions are considered a boon for the treatment of IVDD, but the effectiveness of those strategies is limited. Mesenchymal stem cells (MSCs) have recently emerged as a possible promising regenerative therapy for IVDD due to their paracrine effect, restoration of the degenerated cells, and capacity for differentiation into disc cells. Recent investigations have shown that the pleiotropic effect of MSCs is not related to differentiation capacity but is mediated by the secretion of soluble paracrine factors. Early studies have demonstrated that MSC-derived exosomes have therapeutic potential for treating IVDD by promoting cell proliferation, tissue regeneration, modulation of the inflammatory response, and reduced apoptosis. This paper highlights the current state of MSC-derived exosomes in the field of treatment of IVDD with further possible future developments, applications, and challenges.

Stem Cell-Based Regenerative Therapy and Derived Products in COPD: A Systematic Review and Meta-Analysis

COPD is an incurable disorder, characterized by a progressive alveolar tissue destruction and defective mechanisms of repair and defense leading to emphysema. Currently, treatment for COPD is exclusively symptomatic; therefore, stem cell-based therapies represent a promising therapeutic approach to regenerate damaged structures of the respiratory system and restore lung function. The aim of this study was to provide a quantitative synthesis of the efficacy profile of stem cell-based regenerative therapies and derived products in COPD patients. A systematic review and meta-analysis was performed according to PRISMA-P. Data from 371 COPD patients were extracted from 11 studies. Active treatments elicited a strong tendency towards significance in FEV1 improvement (+71 mL 95% CI -2−145; p = 0.056) and significantly increased 6MWT (52 m 95% CI 18−87; p < 0.05) vs. baseline or control. Active treatments did not reduce the risk of hospitalization due to acute exacerbations (RR 0.77 95% CI 0.40−1.49; p > 0.05). This study suggests that stem cell-based regenerative therapies and derived products may be effective to treat COPD patients, but the current evidence comes from small clinical trials. Large and well-designed randomized controlled trials are needed to really quantify the beneficial impact of stem cell-based regenerative therapy and derived products in COPD.

Parkinson’s Disease and SARS-CoV-2 Infection: Particularities of Molecular and Cellular Mechanisms Regarding Pathogenesis and Treatment

Accumulating data suggest that chronic neuroinflammation-mediated neurodegeneration is a significant contributing factor for progressive neuronal and glial cell death in age-related neurodegenerative pathology. Furthermore, it could be encountered as long-term consequences in some viral infections, including post-COVID-19 Parkinsonism-related chronic sequelae. The current systematic review is focused on a recent question aroused during the pandemic’s successive waves: are there post-SARS-CoV-2 immune-mediated reactions responsible for promoting neurodegeneration? Does the host’s dysregulated immune counter-offensive contribute to the pathogenesis of neurodegenerative diseases, emerging as Parkinson’s disease, in a complex interrelation between genetic and epigenetic risk factors? A synthetic and systematic literature review was accomplished based on the ”Preferred Reporting Items for Systematic Principles Reviews and Meta-Analyses” (PRISMA) methodology, including registration on the specific online platform: International prospective register of systematic reviews—PROSPERO, no. 312183. Initially, 1894 articles were detected. After fulfilling the five steps of the selection methodology, 104 papers were selected for this synthetic review. Documentation was enhanced with a supplementary 47 bibliographic resources identified in the literature within a non-standardized search connected to the subject. As a final step of the PRISMA method, we have fulfilled a Population-Intervention-Comparison-Outcome-Time (PICOT)/Population-Intervention-Comparison-Outcome-Study type (PICOS)—based metanalysis of clinical trials identified as connected to our search, targeting the outcomes of rehabilitative kinesitherapeutic interventions compared to clinical approaches lacking such kind of treatment. Accordingly, we identified 10 clinical trials related to our article. The multi/interdisciplinary conventional therapy of Parkinson’s disease and non-conventional multitarget approach to an integrative treatment was briefly analyzed. This article synthesizes the current findings on the pathogenic interference between the dysregulated complex mechanisms involved in aging, neuroinflammation, and neurodegeneration, focusing on Parkinson’s disease and the acute and chronic repercussions of COVID-19. Time will tell whether COVID-19 neuroinflammatory events could trigger long-term neurodegenerative effects and contribute to the worsening and/or explosion of new cases of PD. The extent of the interrelated neuropathogenic phenomenon remains obscure, so further clinical observations and prospective longitudinal cohort studies are needed.

Antioxidant Biomolecules and Their Potential for the Treatment of Difficult-to-Treat Depression and Conventional Treatment-Resistant Depression

Major depression is a devastating disease affecting an increasing number of people from a young age worldwide, a situation that is expected to be worsened by the COVID-19 pandemic. New approaches for the treatment of this disease are urgently needed since available treatments are not effective for all patients, take a long time to produce an effect, and are not well-tolerated in many cases; moreover, they are not safe for all patients. There is solid evidence showing that the antioxidant capacity is lower and the oxidative damage is higher in the brains of depressed patients as compared with healthy controls. Mitochondrial disfunction is associated with depression and other neuropsychiatric disorders, and this dysfunction can be an important source of oxidative damage. Additionally, neuroinflammation that is commonly present in the brain of depressive patients highly contributes to the generation of reactive oxygen species (ROS). There is evidence showing that pro-inflammatory diets can increase depression risk; on the contrary, an anti-inflammatory diet such as the Mediterranean diet can decrease it. Therefore, it is interesting to evaluate the possible role of plant-derived antioxidants in depression treatment and prevention as well as other biomolecules with high antioxidant and anti-inflammatory potential such as the molecules paracrinely secreted by mesenchymal stem cells. In this review, we evaluated the preclinical and clinical evidence showing the potential effects of different antioxidant and anti-inflammatory biomolecules as antidepressants, with a focus on difficult-to-treat depression and conventional treatment-resistant depression.

Mesenchymal Stem Cell-Derived Exosomes as a Novel Strategy for the Treatment of Intervertebral Disc Degeneration

Intervertebral disc degeneration (IVDD) has been reported to be the most prevalent contributor to low back pain, posing a significant strain on the healthcare systems on a global scale. Currently, there are no approved therapies available for the prevention of the progressive degeneration of intervertebral disc (IVD); however, emerging regenerative strategies that aim to restore the normal structure of the disc have been fundamentally promising. In the last decade, mesenchymal stem cells (MSCs) have received a significant deal of interest for the treatment of IVDD due to their differentiation potential, immunoregulatory capabilities, and capability to be cultured and regulated in a favorable environment. Recent investigations show that the pleiotropic impacts of MSCs are regulated by the production of soluble paracrine factors. Exosomes play an important role in regulating such effects. In this review, we have summarized the current treatments for disc degenerative diseases and their limitations and highlighted the therapeutic role and its underlying mechanism of MSC-derived exosomes in IVDD, as well as the possible future developments for exosomes.

Stem Cell Transplantation and Cell-Free Treatment for Periodontal Regeneration

Increasing attention has been paid to cell-based medicines. Many in vivo and in vitro studies have demonstrated the efficacy of stem cell transplantation for the regeneration of periodontal tissues over the past 20 years. Although positive evidence has accumulated regarding periodontal regeneration using stem cells, the exact mechanism of tissue regeneration is still largely unknown. This review outlines the practicality and emerging problems of stem cell transplantation therapy for periodontal regeneration. In addition, possible solutions to these problems and cell-free treatment are discussed.

Autologous Infusion of Bone Marrow and Mesenchymal Stromal Cells in Patients with Chronic Obstructive Pulmonary Disease: Phase I Randomized Clinical Trial

Background and Objectives

Chronic obstructive pulmonary disease (COPD) is characterized by the destruction of alveolar walls, chronic inflammation and persistent respiratory symptoms. There is no curative clinical treatment for COPD. In this context, cell-based therapy is a promising therapeutic alternative for COPD. Thus, in this open, controlled and randomized Phase I Clinical Trial, we aimed to assess the safety of the infusion of autologous bone marrow mononuclear cells (BMMC), adipose-derived mesenchymal stromal cells (ADSC) and, especially, the safety of concomitant infusion (co-infusion) of BMMC and ADSC as a new therapeutic alternative for COPD. The rationale for co-infusion of BMMC and ADSC is based on the hypothesis of an additive or synergistic therapeutic effect resulting from this association.

Methods

To achieve the proposed objectives, twenty patients with moderate-to-severe COPD were randomly divided into four groups: control group - patients receiving conventional treatment; BMMC group - patients receiving only BMMC; ADSC group - patients receiving only ADSC, and co-infusion group - patients receiving the concomitant infusion of BMMC and ADSC. Patients were assessed for pulmonary function, biochemical profile, and quality of life over a 12 months follow-up.

Results

No adverse events were detected immediately after the infusion of BMMC, ADSC or co-infusion. In the 12-month follow-up, no causal relationship was established between adverse events and cell therapy procedures. Regarding the efficacy, the BMMC group showed an increase in forced expiratory volume (FEV1) and diffusing capacity for carbon monoxide (DLCO). Co-infusion group showed a DLCO, and gas exchange improvement and a better quality of life.

Conclusion

The results obtained allow us to conclude that cell-based therapy with co-infusion of BMMC and ADSC is a safe procedure and a promising therapeutic for COPD. However, additional studies with a greater number of patients are needed before randomized and controlled Phase III clinical trials can be implemented.

Immune Phenomena in Myeloid Neoplasms: An "Egg or Chicken" Question

Immune phenomena are increasingly reported in myeloid neoplasms, and include autoimmune cytopenias/diseases and immunodeficiency, either preceding or complicating acute myeloid leukemia, myelodysplastic syndromes (MDS), chronic myeloproliferative neoplasms, and bone marrow failure (BMF) syndromes. Autoimmunity and immunodeficiency are the two faces of a dysregulated immune tolerance and surveillance and may result, along with contributing environmental and genetic factors, in an increased incidence of both tumors and infections. The latter may fuel both autoimmunity and immune activation, triggering a vicious circle among infections, tumors and autoimmune phenomena. Additionally, alterations of the microbiota and of mesenchymal stem cells (MSCs) pinpoint to the importance of a permissive or hostile microenvironment for tumor growth. Finally, several therapies of myeloid neoplasms are aimed at increasing host immunity against the tumor, but at the price of increased autoimmune phenomena. In this review we will examine the epidemiological association of myeloid neoplasms with autoimmune diseases and immunodeficiencies, and the pivotal role of autoimmunity in the pathogenesis of MDS and BMF syndromes, including the paroxysmal nocturnal hemoglobinuria conundrum. Furthermore, we will briefly examine autoimmune complications following therapy of myeloid neoplasms, as well as the role of MSCs and microbiota in these settings.

Techniques for increasing the yield of stem cell-derived exosomes: what factors may be involved?

Exosomes are nano-scale extracellular vesicles secreted by cells and constitute an important part in the cell-cell communication. The main contents of the exosomes include proteins, microRNAs, and lipids. The mechanism and safety of stem cell-derived exosomes have rendered them a promising therapeutic strategy for regenerative medicine. Nevertheless, limited yield has restrained full explication of their functions and clinical applications To address this, various attempts have been made to explore the up- and down-stream manipulations in a bid to increase the production of exosomes. This review has recapitulated factors which may influence the yield of stem cell-derived exosomes, including selection and culture of stem cells, isolation and preservation of the exosomes, and development of artificial exosomes.

Angiogenic Effects and Crosstalk of Adipose-Derived Mesenchymal Stem/Stromal Cells and Their Extracellular Vesicles with Endothelial Cells

Adipose-derived mesenchymal stem/stromal cells (ASCs) are an adult stem cell population able to self-renew and differentiate into numerous cell lineages. ASCs provide a promising future for therapeutic angiogenesis due to their ability to promote blood vessel formation. Specifically, their ability to differentiate into endothelial cells (ECs) and pericyte-like cells and to secrete angiogenesis-promoting growth factors and extracellular vesicles (EVs) makes them an ideal option in cell therapy and in regenerative medicine in conditions including tissue ischemia. In recent angiogenesis research, ASCs have often been co-cultured with an endothelial cell (EC) type in order to form mature vessel-like networks in specific culture conditions. In this review, we introduce co-culture systems and co-transplantation studies between ASCs and ECs. In co-cultures, the cells communicate via direct cell-cell contact or via paracrine signaling. Most often, ASCs are found in the perivascular niche lining the vessels, where they stabilize the vascular structures and express common pericyte surface proteins. In co-cultures, ASCs modulate endothelial cells and induce angiogenesis by promoting tube formation, partly via secretion of EVs. In vivo co-transplantation of ASCs and ECs showed improved formation of functional vessels over a single cell type transplantation. Adipose tissue as a cell source for both mesenchymal stem cells and ECs for co-transplantation serves as a prominent option for therapeutic angiogenesis and blood perfusion in vivo.

Stem cell therapy in liver regeneration: Focus on mesenchymal stem cells and induced pluripotent stem cells

The liver has the ability to repair itself after injury; however, a variety of pathological changes in the liver can affect its ability to regenerate, and this could lead to liver failure. Mesenchymal stem cells (MSCs) are considered a good source of cells for regenerative medicine, as they regulate liver regeneration through different mechanisms, and their efficacy has been demonstrated by many animal experiments and clinical studies. Induced pluripotent stem cells, another good source of MSCs, have also made great progress in the establishment of organoids, such as liver disease models, and in drug screening. Owing to the recent developments in MSCs and induced pluripotent stem cells, combined with emerging technologies including graphene, nano-biomaterials, and gene editing, precision medicine and individualized clinical treatment may be realized in the near future.

Mesenchymal Stem/Stromal Cells and Their Derivates in Acute Diseases: Emergency in the Post-COVID-19 Times

The current coronavirus disease-19 (COVID-19) pandemic has strongly revived the pressing need to incorporate new therapeutic alternatives to deal with medical situations that result in a dramatic breakdown in the body's normal homeostasis [...].

Exosomes as New Biomarkers and Drug Delivery Tools for the Prevention and Treatment of Various Diseases: Current Perspectives

Exosomes are nano-sized vesicles secreted by most cells that contain a variety of biological molecules, such as lipids, proteins and nucleic acids. They have been recognized as important mediators for long-distance cell-to-cell communication and are involved in a variety of biological processes. Exosomes have unique advantages, positioning them as highly effective drug delivery tools and providing a distinct means of delivering various therapeutic agents to target cells. In addition, as a new clinical diagnostic biomarker, exosomes play an important role in many aspects of human health and disease, including endocrinology, inflammation, cancer, and cardiovascular disease. In this review, we summarize the development of exosome-based drug delivery tools and the validation of novel biomarkers, and illustrate the role of exosomes as therapeutic targets in the prevention and treatment of various diseases.

Role of Exosomal MicroRNAs and Their Crosstalk with Oxidative Stress in the Pathogenesis of Osteoporosis

Osteoporosis (OP) is an aging-related disease involving permanent bone tissue atrophy. Most patients with OP show high levels of oxidative stress (OS), which destroys the microstructure of bone tissue and promotes disease progression. Exosomes (exos) help in the delivery of microRNAs (miRNAs) and allow intercellular communication. In OP, exosomal miRNAs modulate several physiological processes, including the OS response. In the present review, we aim to describe how exosomal miRNAs and OS contribute to OP. We first summarize the relationship of OS with OP and then detail the features of exos along with the functions of exo-related miRNAs. Further, we explore the interplay between exosomal miRNAs and OS in OP and summarize the functional role of exos in OP. Finally, we identify the advantages of exo-based miRNA delivery in treatment strategies for OP. Our review seeks to improve the current understanding of the mechanism underlying OP pathogenesis and lay the foundation for the development of novel theranostic approaches for OP.

Microfluidic Tools for Enhanced Characterization of Therapeutic Stem Cells and Prediction of Their Potential Antimicrobial Secretome

Antibiotic resistance is creating enormous attention on the development of new antibiotic-free therapy strategies for bacterial diseases. Mesenchymal stromal stem cells (MSCs) are the most promising candidates in current clinical trials and included in several cell-therapy protocols. Together with the well-known immunomodulatory and regenerative potential of the MSC secretome, these cells have shown direct and indirect anti-bacterial effects. However, the low reproducibility and standardization of MSCs from different sources are the current limitations prior to the purification of cell-free secreted antimicrobial peptides and exosomes. In order to improve MSC characterization, novel label-free functional tests, evaluating the biophysical properties of the cells, will be advantageous for their cell profiling, population sorting, and quality control. We discuss the potential of emerging microfluidic technologies providing new insights into density, shape, and size of live cells, starting from heterogeneous or 3D cultured samples. The prospective application of these technologies to studying MSC populations may contribute to developing new biopharmaceutical strategies with a view to naturally overcoming bacterial defense mechanisms.