Mesenchymal stem cells and immunomodulation: current status and future prospects

Gelatin sponge patch grafting of microcryogel-based three-dimensional mesenchymal stem cells to alleviate acute liver failure

The clinical application of human umbilical cord mesenchymal stem cells (hUCMSCs) in the treatment of liver failure faces challenges due to cell quality, short engraftment time, and limited efficacy. Here, gelatin microcryogel (GM) microcarriers with pore sizes ranging from 15 to 36 μm were tuned from mixed gelatin and glutaraldehyde to develop a 3D culture system of hUCMSCs with improved therapeutic effects. Bulk RNA sequencing and in vitro assays showed that 3D-hUCMSCs exhibited significant improvement in signaling pathways related to paracrine secretion and anti-inflammation. These 3D-hUCMSCs superior compared to 2D-hUCMSCs not only in terms of paracrine secretion, protection from oxidation, and resistance to mechanical force damage, but also had better liver function improvement effect than 2D-hUCMSCs when they were transplanted as single cells into liver injury mice. Furthermore, a gelatin sponge patch grafting (GSPG) strategy was developed to enable the direct engraftment of 3D-hUCMSCs within the GM microcarriers. The results showed that overall engraftment in the host liver was significantly improved, and the life span of transplanted hosts was extended. Our study provided a practical strategy to achieve high engraftment and long retraining time of 3D-hUCMSCs in rescuing acute liver failure with gelatin matrixes.

Investigation of the stemness and wound-healing potential of long-term cryopreserved stromal vascular fraction cells

Introduction

Stromal vascular fraction (SVF), a heterogeneous cell population primarily derived from adipose tissue, is widely utilized in regenerative therapies for its wound-healing properties and accessibility. While its immediate availability is advantageous, repeated harvesting can be burdensome, especially for elderly patients, and the regenerative capacity of SVF declines with donor age. Long-term cryopreservation offers a potential solution by allowing the banking of SVF from younger donors for future use; however, the impact of this process on SVF functionality remains elusive. This study investigates the stemness and wound-healing potential of SVF following prolonged cryopreservation.

Methods

SVF cells were isolated from adipose tissue harvested from twelve patients and cryopreserved for either two months (short-term cryopreserved SVF, S-SVF) or 12-13 years (long-term cryopreserved SVF, L-SVF), with six patients in each group. In vitro assays assessed cell viability and stemness, while in vivo assays evaluated wound-healing ability by administering thawed SVF cells from each group to dorsal wounds in immunodeficient mice, compared with a control group. Non-parametric statistical tests analyzed the differences between groups.

Results

L-SVF exhibited significantly lower stemness compared to S-SVF. Importantly, the L-SVF group showed significantly improved wound healing compared with the control group, although the wound-healing effect of L-SVF was inferior to that of the S-SVF.

Conclusion

This study demonstrated that, despite reduced stemness, L-SVF retains partial wound-healing potential after 12-13 years of cryopreservation. These findings highlight the need for optimized cryopreservation protocols to enhance SVF viability and regenerative capacity for clinical applications.

Multimodal Function of Mesenchymal Stem Cells in Psoriasis Treatment

Psoriasis is a chronic inflammatory disease mediated by the innate and adaptive immune systems, and its pathogenesis involves multiple aspects, including abnormal interleukin (IL)-23-Th17 axis, dysfunction of Tregs and other immune cells, and a complex relationship between keratinocytes and the vascular endothelium. Dysfunction of mesenchymal stem cells in psoriatic skin may also be the main reason for the dysregulated inflammatory response. Mesenchymal stem cells, a type of adult stem cells with multidifferentiation potential, are involved in the regulation of multiple links and targets in the pathogenesis of psoriasis. Thus, a detailed exploration of these mechanisms may lead to the development of new therapeutic strategies for the treatment of psoriasis. In this paper, the role of mesenchymal stem cells in skin homeostasis, the pathogenesis of psoriasis, and the multimodal function of using mesenchymal stem cells in the treatment of psoriasis are reviewed.

Identifying Immunomodulatory Subpopulations of Adipose Stromal Vascular Fraction and Stem/Stromal Cells Through Single-Cell Transcriptomics and Bulk Proteomics

A primary therapeutic characteristic of mesenchymal stem/stromal cells (MSCs) is their immunomodulatory activity. Adipose-derived stem/stromal cells (ASCs) are an abundant and easily isolated source of MSCs shown to have high immunosuppressive activity, making them attractive for therapy. Understanding the heterogeneous immunomodulatory potential of ASCs within the stromal vascular fraction (SVF) of adipose tissue could better inform treatment strategies. In this study, we integrate single-cell RNA sequencing (scRNA seq) with bulk proteomics to characterize subpopulations of SVF-derived ASCs that are phenotypically similar to cytokine-licensed, cultured ASCs. To better define the licensing process, we present scRNA seq and bulk proteomics data of cultured (P2) ASCs exposed to inflammatory cytokines, showing enrichment of pathways related to inflammation and apoptosis that positively correlate to the cytokine-mediated, trajectory-derived pseudotime. Using the Scissor algorithm, we integrate the proteomics data with uncultured (P0) SVF scRNA seq data, identifying an ASC subpopulation that is phenotypically like the cytokine-stimulated ASCs (Scissor-positive). Interactome analysis identifies Scissor-positive ASCs as stress adaptive immune regulators that function through IL6 and broad SEMA4 interactions and higher Visfatin signaling, while Scissor-negative ASCs show strong signatures of ECM remodeling through FN1 and immunosuppression through THY1 and MIF signaling. Our multimodal, integrative approach enabled identification of previously unidentified, distinct ASC subpopulations with differing immunomodulatory phenotypes that are present in, and can potentially be selected from, P0 SVF ASCs.

Therapeutic effect of hUC-MSCs from different transplantation routes on acute liver failure in rats

Objective

Acute liver failure (ALF) is a rare yet serious clinical syndrome. Recent studies have indicated that stem cells can effectively treat this condition. However, the optimal route for stem cell transplantation in the treatment of ALF remains unclear. This study aims to investigate the most effective transplantation route for stem cell therapy in ALF.

Methods

Human umbilical cord mesenchymal stem cells (hUC-MSCs) expressing both luciferase and green fluorescent protein were generated using a lentiviral vector. The hUC-MSCs were transplanted via the tail vein, portal vein, and abdominal cavity. The survival and distribution of the transplanted hUC-MSCs in rats were assessed through in vivo imaging and immunofluorescence. Furthermore, the therapeutic effects of hUC-MSCs transplanted via different routes on ALF were compared.

Results

The survival time of hUC-MSCs transplanted via the tail vein and portal vein was shorter compared to those transplanted intraperitoneally. The distribution of hUC-MSCs varied by transplantation route: those injected via the tail vein and portal vein were primarily found in the lungs and liver, respectively, while intraperitoneally transplanted hUC-MSCs predominantly localized in the abdominal cavity. In ALF rats, hUC-MSCs transplanted via the tail vein and portal vein improved survival rates, enhanced liver pathology, and reduced levels of inflammatory cytokines in liver tissue. In contrast, abdominal transplantation of hUC-MSCs showed no significant therapeutic effect.

Conclusion

hUC-MSCs transplanted via the tail vein and portal vein exhibited similar therapeutic effects on ALF; however, abdominal transplantation of hUC-MSCs showed no significant effect.

Immune and Angiogenic Profiling of Mesenchymal Stem Cell Functions in a Subcutaneous Microenvironment for Allogeneic Islet Transplantation

Islet transplantation offers a promising treatment for type 1 diabetes (T1D), by aiming to restore insulin production and improve glycemic control. However, T1D is compounded by impaired angiogenesis and immune dysregulation, which hinder the therapeutic potential of cell replacement strategies. To address this, this work evaluates the proangiogenic and immunomodulatory properties of mesenchymal stem cells (MSCs) to enhance vascularization and modulate early-stage immune rejection pathways in the context of islet allotransplantation. This work employs the Neovascularized Implantable Cell Homing and Encapsulation (NICHE) platform, a subcutaneous vascularized implant with localized immunomodulation developed by the group. This study assesses vascularization and immune regulation provided by MSCs, aiming to improve islet survival and integration in diabetic rats while considering sex as a biological variable. These findings demonstrate that MSCs significantly enhance vascularization and modulate the local microenvironment during the peri-transplant period. Importantly, this work discovers sex-specific differences in both processes, which influence islet engraftment and long-term function.

The complement system and kidney cancer: pathogenesis to clinical applications

Kidney cancer poses unique clinical challenges because of its resistance to conventional treatments and its tendency to metastasize. The kidney is particularly susceptible to dysfunction of the complement system, an immune network that tumors often exploit. Recent discoveries have highlighted that the complement system not only plays a crucial role in immune surveillance and defense in the circulatory system, but also functions intracellularly and autonomously. This concept has shifted the focus of investigation toward understanding how complement proteins influence cancer progression by regulating the tumor microenvironment (TME), cell signaling, proliferation, metabolism, and the immune response. With the complement system and its inhibitors emerging as a promising new class of immunotherapeutics and potential complement-targeted treatments advancing through development pipelines and clinical trials, this Review provides a timely examination of how harnessing the complement system could lead to effective tumor treatments and how to strategically combine complement inhibitors with other cancer treatments, offering renewed hope in the fight against kidney cancer.

The Potential Hepatocyte Differentiation Targets and MSC Proliferation by FH1

The main cause of acute liver failure (ALF) is hepatocellular necrosis, which induces liver repair dysfunction and leads to high mortality. In recent years, studies have increasingly shown that stem cell-derived hepatocyte-like cells (HLCs) can be used for treatment in animal models of ALF. Notably, a hepatocyte differentiation strategy based on the small-molecule compound functional hit 1 (FH1) successfully replaces HGF to promote the maturation of HLCs, but the underlying mechanism is still unclear. In this study, we used network pharmacology analysis to clarify the important role of the HGF/c-Met signalling pathway in FH1-induced hepatocyte (FH1-iHeps) differentiation. After FH1 was added to mesenchymal stem/stromal cells (MSCs), proliferation and cell cycle progression were rescued by treatment with a tyrosine kinase (c-Met) inhibitor. Additionally, c-Met signalling in MSCs was significantly increased by treatment with FH1, as shown by the increased c-Met, p-p38, p-AKT and p-ERK1/2 protein levels. FH1-iHeps efficiently improved the liver function of mice with acute liver injury and prolonged their lifespan. These data provide new insight into the mechanisms regulating the stemness properties of human umbilical cord-derived stem cells (hUC-MSCs) and reveal a previously unrecognised link between FH1 and c-Met in directing hepatocyte differentiation.

Understanding the Mechanisms of Chemotherapy-Related Cardiotoxicity Employing hiPSC-Derived Cardiomyocyte Models for Drug Screening and the Identification of Genetic and Epigenetic Variants

Chemotherapy-related cardiotoxicity (CTRTOX) is a profound and common side effect of cancer-based therapy in a subset of patients. The underlying factors and the associated mechanisms contributing to severe toxicity of the heart among these patients remain unknown. While challenges remain in accessing human subjects and their ventricular cardiomyocytes (CMs), advancements in human induced pluripotent stem cell (hiPSC)-technology-based CM differentiation protocols over the past few decades have paved the path for iPSC-based models of human cardiac diseases. Here, we offer a detailed analysis of the underlying mechanisms of CTRTOX. We also discuss the recent advances in therapeutic strategies in different animal models and clinical trials. Furthermore, we explore the prospects of iPSC-based models for identifying novel functional targets and developing safer chemotherapy regimens for cancer patients that may be beneficial for developing personalized cardioprotectants and their application in clinical practice.

Extracellular vesicles derived from mesenchymal stem cells alleviate depressive-like behavior in a rat model of chronic stress

Depression is a prevalent chronic psychiatric disorder with a growing impact on global health. Current treatments often fail to achieve full remission, highlighting the need for alternative therapeutic strategies. Mesenchymal stem cells (MSCs) have attracted significant interest for their therapeutic potential in neuropsychiatric disorders, primarily due to their capacity to target neuroinflammation. This study aimed to investigate if extracellular vesicles derived from human umbilical MSCs (hucMSCs) promote behavioral beneficial actions in a rat model of chronic unpredictable mild stress (CUMS). We show that a single dose of hucMSCs or their derived EVs (hucMSC-EVs) via the tail vein alleviated depressive-like behavior in rats, reduced markers of neuroinflammation, reduced pro-inflammatory cytokines (IL-1β and TNF-α), and increased the number and dendritic complexity of DCX-positive cells in the dentate gyrus. Proteomic analysis of EVs revealed the presence of proteins involved in modulation of inflammatory processes and cell activation. Our study demonstrates EVs derived from hucMSCs can effectively mitigate depressive symptoms by modulating neuroinflammatory pathways and enhancing neurogenesis. These findings support further exploration of MSC-derived EVs as a novel therapeutic option for neuropsychiatric disorders.

Ganglioside expression delineates human mesenchymal stem/stromal cell populations derived from different tissue sources

Prior studies have indicated that human embryonic stem cells can be distinguished from those of other mammals based on variable expression of a class of membrane glycolipids known as glycosphingolipids (GSLs), raising the question as to whether GSL display could be utilized to phenotypically define subsets of human adult stem cell populations. Adult stem cells known as "mesenchymal stem/stromal cells" (MSCs) have shown immense promise in therapeutic applications for a variety of clinical indications. Most commonly, these cells are harnessed and then culture-expanded from bone-marrow (BM-MSCs) or from adipose tissue (A-MSCs) sources. Though operational differences exist between human BM-MSCs and A-MSCs, no surface markers have been characterized to date that distinguish these as distinct subsets of culture-expanded human adult stem cells. Accordingly, we isolated GSLs from primary cultures of marrow- and adipose-derived human MSCs and an unbiased screen was performed by mass spectrometry (via matrix-assisted laser desorption/ionization (MALDI)-quadrupole ion trap (QIT)-time-of-flight (TOF), hence, via "MALDI-QIT-TOF") to analyze all component glycans. Flow cytometry was then undertaken to assess the relative levels of expression of MS-defined glycan determinants, followed by RT-qPCR to measure transcripts of genes encoding key enzymes involved in glycolipid biosynthesis. Notably, our data indicate that neither BM- nor A-MSCs display any significant level of either lacto-series or neolacto-series GSLs, but distinct differences exist in GSL species among A-MSCs and BM-MSCs: while both cell types express GSLs of the ganglio- and the globo-series, the ganglio-series GSLs GD3 and GD2 and the globo-series GSL SSEA-4 (also known as sialylGb5) are dominantly expressed only among human BM-MSCs. These structural features are shaped by divergent patterns of glycosyltransferase gene expression, with striking differences between BM- and A-MSCs in the expression of transcripts encoding GD3 synthase, GM2/GD2 synthase, and Gb5 synthase. Importantly, expression of GD3, GD2, and SSEA-4 is markedly diminished on differentiation of BM-MSCs, and co-cultures of A-MSCs and BM-MSCs show that the expression of GD3, GD2, and SSEA-4 is a cell-intrinsic feature of BM-MSCs. These data stratify the glycosignature(s) of human MSCs derived from different tissue sources, provide direct evidence that expression of these structures is cell stage-/lineage-specific, unveil the mechanistic basis of the differential expression of these glycan determinants, and draw attention to how knowledge of the MSC glycosignature can impact cytotherapeutic strategies.

Adipose Tissue Stem Cells (ASCs) and ASC-Derived Extracellular Vesicles Prevent the Development of Experimental Peritoneal Fibrosis

Cell therapy utilizing mesenchymal stromal cells (MSCs) through paracrine mechanisms holds promise for regenerative purposes. Peritoneal fibrosis (PF) is a significant complication of peritoneal dialysis. Various strategies have been proposed to protect the peritoneal membrane (PM). This study explores the effectiveness of adipose-tissue-derived stem cells (ASCs) and extracellular vesicles (EVs) at mitigating PF using a rat model of PF induced by chlorhexidine gluconate. ASC and EV treatments effectively prevented an increase in the thickness of the PM and diminished the number of myofibroblasts, fibronectin expression, collagen III expression, and PF-related factors such as TGF-β and FSP-1. Smad3 gene expression decreased in the treatment groups, whereas Smad7 gene expression increased in treated animals. In addition, ASC and EV injections showed potent anti-inflammatory effects. Glucose transport through the PM remained unaffected in relation to the PF group; both treatments promoted an increase in ultrafiltration (UF) capacity. The PF+EVs treated group showed the highest increase in UF capacity. Another critical aspect of ASC and EV treatments was their impact on neoangiogenesis in the PM which is vital for UF capacity. Although the treated groups displayed a significant decrease in VEGF expression in the PM, peritoneal function remained effective. In conclusion, within the experimental PF model, both ASC and EV treatments demonstrated anti-inflammatory effects and comparably hindered the progression of PF. The EV treatment exhibited superior preservation of peritoneal function, along with enhanced UF capacity. These findings suggest the potential of ASCs and EVs as novel therapeutic approaches to prevent the development of PF associated with peritoneal dialysis.

High throughput morphological screening identifies chemically defined media for mesenchymal stromal cells that enhances proliferation and supports maintenance of immunomodulatory function

BACKGROUND

While mesenchymal stromal cell (MSC) therapies show promise for treating several indications due to their regenerative and immunomodulatory capacity, clinical translation has yet to be achieved due to a lack of robust, scalable manufacturing practices. Expansion using undefined fetal bovine serum (FBS) or human platelet lysate contributes to MSC functional heterogeneity and limits control of product quality. The need for tunable and consistent media has thus motivated development of chemically defined media (CDM). However, CDM development strategies are often limited in their screening approaches and unable to reliably assess the impact of media on MSC function, often neglecting high-level interactions of media components such as growth factors. Given that MSC morphology has been shown to predict their immunomodulatory function, we employed a high throughput screening (HTS) approach to elucidate effects of growth factor compositions on MSC phenotype and proliferation in a custom CDM.

METHODS

HTS of eight growth factors in a chemically defined basal medium (CDBM) was conducted via a two-level, full factorial design using adipose-derived MSCs. Media hits were identified leveraging cell counts and morphological profiles. After validating phenotypic responses to hits across multiple donors, MSCs were cultured over three passages in serum-containing medium (SCM) and CDM hits and assayed for growth and immunomodulatory function. Finally, growth factor concentrations in one hit were further refined, and MSC growth and function was assessed.

RESULTS

Our HTS approach led to the discovery of several CDM formulations that enhanced MSC proliferation and demonstrated wide ranging impacts on MSC immunomodulation. Notably, two hits showed 4X higher growth compared to SCM over 3 passages without compromising immunomodulatory function. Refinement of one CDM hit formulation reduced growth factor concentrations by as much as 90% while maintaining superior growth and similar function to SCM. Altogether, distinct MSC morphological profiles observed from screening were indicative of differential MSC quality that allowed for development of an effective CDM for MSC expansion.

CONCLUSIONS

Overall, this highlights how our HTS approach led to the development of CDM formulations for robust MSC expansion and serves as a generalizable tool for improvement of MSC manufacturing processes.

Matrix stiffness and viscoelasticity influence human mesenchymal stem cell immunomodulation

Human mesenchymal stem cells (hMSCs) have immense wound healing potential due to their immunomodulatory behavior. To control this behavior and reduce heterogeneity, researchers look to biomaterials, as matrix stiffness and viscoelasticity have been shown to control hMSC immunomodulation. However, the understanding of the effects of these biophysical cues on hMSC immunomodulation remains limited; a broad study investigating the potentially synergistic effects of matrix stiffness and viscoelasticity on hMSC immunomodulation is needed in order to support future work developing biomaterials for hMSC wound healing applications. We developed polyacrylamide (PAAm) gels with varying matrix stiffnesses with or without a viscoelastic element and explored the effects of these on hMSC-matrix interactions and immunomodulatory cytokine expression in both a normal growth media and an immunomodulatory growth media mimetic of a chronic, non-healing wound. Expression of IL-10, VEGF, and PGE2 were upregulated in immunomodulatory growth media over normal growth media, demonstrating the synergistic effects of biochemical signaling on hMSC immunomodulatory behavior. In addition, the addition of a viscoelastic element had both inhibitory and accentuating effects based on the cytokine and biochemical signaling in the cell culture media. Overall, this study provides a broad perspective on the immunomodulatory behavior of hMSCs due to stiffness and viscoelasticity.

Spheroids from Epithelial and Mesenchymal Cell Phenotypes as Building Blocks in Bioprinting (Review)

Most tissues and organs are based on cells of the epithelial and mesenchymal phenotypes. Epithelial cells build protective barriers, have a key role in absorption and secretion, and participate in metabolism. Characterized by high plasticity and ability to migrate, mesenchymal cells ensure structural support, promote tissue restoration and are important for matrix remodeling. Interaction between these two cell types is critical for maintaining the body integrity and functioning. Modern tissue engineering is aimed at creation of artificial tissues and organs that have the required cellular composition, mechanical properties and functional potential for medical usage. One of the most popular methods of tissue engineering is 3D bioprinting, which allows creating complex three-dimensional structures with specified characteristics. Recently, special attention has been paid to bioprinting with spheroids being three-dimensional cellular aggregates that can be used as building blocks for tissue-engineered structures. Due to numerous cell-to-cell contacts and accumulation of extracellular matrix, spheroids ensure conditions allowing to form anatomical tissues and organs. To optimize bioprinting conditions, one shall precisely understand the mechanical properties of spheroids, as they directly affect the ability of cells to migrate and fuse, and thus the rate of construct formation and its overall morphology. This review summarizes the available data on the differences in mechanical properties of epithelial and mesenchymal spheroids, examines methods for their co-culturing in various applications of regenerative medicine, as well as analyzes the peculiarities of their use in different bioprinting methods to obtain high-quality tissue constructs.

Gold Mesoporous Silica-Coated Nanoparticles for Quantifying and Qualifying Mesenchymal Stem Cell Distribution; a Proof-of-Concept Study in Large Animals

Mesenchymal stem cells (MSCs) have demonstrated promising therapeutic potential across a wide range of diseases including (multi) organ injury in neonates. Despite the reported preclinical successes of MSC therapy, a major challenge in their clinical translation is a limited understanding of their biodistribution after administration. This knowledge gap needs to be addressed to allow clinical implementation. Accordingly, in this study, we propose that silica-coated gold nanoparticles (AuMS) are a promising tool for in vivo MSC tracing. This study explores the use of AuMS for both qualitative and quantitative MSC tracking in vivo after intravenous (I.V.) administration in a translational ovine model of preterm birth. Additionally, we assess the impact of AuMS labeling on the immunomodulatory functions of MSC, which play an important role in the therapeutic potency of these cells. Quantitative and qualitative assessment of AuMS-labeled MSC was performed in vivo using fluorescent microscopy and inductively coupled plasma mass spectrometry (ICP-MS), respectively. AuMS localization in the liver, spleen, and lung was demonstrated. In vitro studies showed that AuMS cellular uptake occurs within 6 h and remains internalized up to 72 h. Labeled MSC maintained their immune phenotype and did not alter their immunomodulatory capacity and proliferation abilities. Overall, we demonstrate that AuMS is a promising, biocompatible nanoprobe for MSC tracing up to 72 h post-I.V. administration.

Improving the therapeutic profile of MSCs: Cytokine priming reduces donor-dependent heterogeneity and enhances their immunomodulatory capacity

Introduction

MSCs exhibit regenerative, anti-inflammatory and immunomodulatory properties due to the large amount of cytokines, chemokines and growth factors they secrete. MSCs have been extensively evaluated in clinical trials, however, in some cases their therapeutic effects are variable. Therefore, strategies to improve their therapeutic potential, such as preconditioning with proinflammatory factors, have been proposed. Several priming approaches have provided non-conclusive results, and the duration of priming effects on MSC properties or their response to a second inflammatory stimulus have not been fully addressed.

Methods

We have investigated the impact of triple cytokine priming in MSCs on their characterization and viability, their transcriptomic profile, the functionality of innate and acquired immune cells, as well as the maintenance of the response to priming over time, their subsequent responsiveness to a second inflammatory stimulus.

Results

Priming MSCs with proinflammatory cytokines (CK-MSCs) do not modify the differentiation capacity of MSCs, nor their immunophenotype and viability. Moreover, cytokine priming enhances the anti-inflammatory and immunomodulatory properties of MSCs against NK and dendritic cells, while maintaining the same T cell immunomodulatory capacity as unstimulated MSCs. Thus, they decrease T-lymphocytes and NK cell proliferation, inhibit the differentiation and allostimulatory capacity of dendritic cells and promote the differentiation of monocytes with an immunosuppressive profile. In addition, we have shown for the first time that proinflammatory priming reduces the variability between different donors and MSC origins. Finally, the effect on CK-MSC is maintained over time and even after a secondary inflammatory stimulus.

Conclusions

Cytokine-priming improves the therapeutic potential of MSCs and reduces inter-donor variability.

3D-Printed PCL Scaffolds Loaded with bFGF and BMSCs Enhance Tendon-Bone Healing in Rat Rotator Cuff Tears by Immunomodulation and Osteogenesis Promotion

Rotator cuff tears are the most common conditions in sports medicine and attract increasing attention. Scar tissue healing at the tendon-bone interface results in a high rate of retears, making it a major challenge to enhance the healing of the rotator cuff tendon-bone interface. Biomaterials currently employed for tendon-bone healing in rotator cuff tears still exhibit limited efficacy. As a promising technology, 3D printing enables the customization of scaffold shapes and properties. Bone marrow mesenchymal stem cells (BMSCs) have multidifferentiation potential and valuable immunomodulatory effects. The basic fibroblast growth factor (bFGF), known for its role in proliferation, has been reported to promote osteogenesis. These properties make them applicable in tissue engineering. In this study, we developed a 3D-printed polycaprolactone (PCL) scaffold loaded with bFGF and BMSCs (PCLMF) to restore the tendon-bone interface and regulate the local inflammatory microenvironment. The PCLMF scaffolds significantly improved the biomechanical strength, histological score, and local bone mineral density at regenerated entheses at 2 weeks postsurgery and achieved optimal performance at 8 weeks. Furthermore, PCLMF scaffolds facilitated BMSC osteogenic differentiation and suppressed adipogenic differentiation both in vivo and in vitro. In addition, RNA-seq showed that PCLMF scaffolds could regulate macrophage polarization and inflammation through the MAPK pathway. The implanted scaffold demonstrated excellent biocompatibility and biosafety. Therefore, this study proposes a promising and practical strategy for enhancing tendon-bone healing in rotator cuff tears.

Protective Effect and Molecular Mechanism of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Diabetic Foot Ulcers

This study explores the protective mechanism of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in diabetic foot ulcer (DFU). Human umbilical cord MSCs (HucMSCs) were identified via osteogenesis and adipogenic differentiation, as well as flow cytometry. EVs were isolated from HucMSCs and characterized using transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. Fluorescence microscopy revealed the uptake of PKH67-labeled EVs and Cy3-labeled microRNA-21-5p (miR-21-5p) by human skin fibroblasts (HSFs). EVs were cocultured with HSFs, and cell proliferation and migration were assessed using Cell Counting Kit-8, colony formation, scratch, and Transwell assays. miR-21-5p overexpression in EVs was evaluated for its role in promoting HSF functions. The expression levels of miR-21-5p, Krüppel-like factor 6 (KLF6), α-smooth muscle actin, and collagen type I alpha 1 chain were analyzed via quantitative real-time PCR and Western blotting. The interaction between miR-21-5p and KLF6 was confirmed through a dual-luciferase reporter gene assay. HucMSC-derived EVs enhanced the proliferation and migration of HSFs under high glucose by delivering miR-21-5p, which targeted and inhibited KLF6. Overexpression of KLF6 counteracted the pro-proliferative and migratory effects of EVs carrying miR-21-5p. Overall, these findings suggest that HucMSC-EVs promote HSF proliferation and migration by downregulating KLF6 via miR-21-5p delivery, offering a potential therapeutic strategy for DFU.

Regional Gene Therapy for Bone Tissue Engineering: A Current Concepts Review

The management of segmental bone defects presents a complex reconstruction challenge for orthopedic surgeons. Current treatment options are limited by efficacy across the spectrum of injury, morbidity, and cost. Regional gene therapy is a promising tissue engineering strategy for bone repair, as it allows for local implantation of nucleic acids or genetically modified cells to direct specific protein expression. In cell-based gene therapy approaches, a variety of different cell types have been described including mesenchymal stem cells (MSCs) derived from multiple sources-bone marrow, adipose, skeletal muscle, and umbilical cord tissue, among others. MSCs, in particular, have been well studied, as they serve as a source of osteoprogenitor cells in addition to providing a vehicle for transgene delivery. Furthermore, MSCs possess immunomodulatory properties, which may support the development of an allogeneic "off-the-shelf" gene therapy product. Identifying an optimal cell type is paramount to the successful clinical translation of cell-based gene therapy approaches. Here, we review current strategies for the management of segmental bone loss in orthopedic surgery, including bone grafting, bone graft substitutes, and operative techniques. We also highlight regional gene therapy as a tissue engineering strategy for bone repair, with a focus on cell types and cell sources suitable for this application.

The Multifaceted Roles of MicroRNA-181 in Stem Cell Differentiation and Cancer Stem Cell Plasticity

Stem cells are undifferentiated or partially differentiated cells with an extraordinary ability to self-renew and differentiate into various cell types during growth and development. The epithelial-mesenchymal transition (EMT), a critical developmental process, enhances stem cell-like properties in cells, and is associated with both normal stem cell function and the formation of cancer stem cells. Cell stemness and the EMT often coexist and are interconnected in various contexts. Cancer stem cells are a critical tumor cell population that drives tumorigenesis, cancer progression, drug resistance, and metastasis. Stem cell differentiation and the generation of cancer stem cells are regulated by numerous molecules, including microRNAs (miRNAs). These miRNAs, particularly through the modulation of EMT-associated factors, play major roles in controlling the stemness of cancer stem cells. This review presents an up-to-date summary of the regulatory roles of miR-181 in human stem cell differentiation and cancer cell stemness. We outline studies from the current literature and summarize the miR-181-controlled signaling pathways responsible for driving human stem cell differentiation or the emergence of cancer stem cells. Given its critical role in regulating cell stemness, miR-181 is a promising target for influencing human cell fate. Modulation of miR-181 expression has been found to be altered in cancer stem cells' biological behaviors and to significantly improve cancer treatment outcomes. Additionally, we discuss challenges in miRNA-based therapies and targeted delivery with nanotechnology-based systems.

Curing cryptoglandular anal fistulas-Is it possible without surgery?

BACKGROUND

Empirical reviews suggested that cryptoglandular anal fistulas require surgical resolution. However, some reports have indicated the possibility of nonsurgical and conservative treatment, which is discussed in this review.

METHODS

This review explores the potential of nonsurgical approaches for curing anal fistulas through bacterial inhibition and immunomodulation. The longstanding cryptoglandular theory has been a subject of controversy, prompting the reevaluation of conventional surgical interventions for anal fistulas. The review was conducted through database searches, including Medline, EMBASE, PubMed, and the Cochrane Library.

RESULTS

Emerging evidence suggests that targeting the anaerobic environments present in anal fistulas and perianal abscesses and eradicating bacteria and their by-products may be critical for successful treatment. Immunomodulatory strategies show promise as a potential avenue for the nonsurgical management of anal fistulas.

CONCLUSIONS

Ongoing developments in pharmacological research offer opportunities for alternative treatment options, shedding light on the prospects of noninvasive anal fistula management.

Enhancing inhibitory effect in SMMC-7721 hepatoma cells through combined treatment of gallic acid and hUC-MSCs-Exos

BACKGROUND

Clinically, hepatoma patients are more frequently encountered in the intermediate and advanced stages. Consequently, the majority of patients miss out on the chance to undergo liver transplantation or radical surgery. Radiotherapy and chemotherapy often fall short of delivering satisfactory outcomes. The incidence and mortality rates for liver cancer approach nearly 100%. In recent years, both exosomes (Exos) and natural chemical compounds have demonstrated robust anti-cancer properties; however, the synergistic effect of their combination remains unexplored.

METHODS

Exos were extracted from human umbilical cord mesenchymal stem cells (hUC-MSCs). The impact of gallic acid (GA), hUC-MSCs-Exos, and their combined administration on the proliferation inhibition rate and apoptosis of SMMC-7721 hepatoma cells was assessed to ascertain the efficacy differences before and after the combined treatment. A combination of cells metabolomics and network pharmacology techniques was employed to investigate the underlying mechanisms of action. The pivotal targets associated with glycolysis, inflammation, and oxidative stress pathways were confirmed through ELISA assays.

RESULTS

The findings elucidate that GA profoundly impedes the proliferation of SMMC-7721 hepatoma cells and instigates apoptotic processes therein. While the impact of hUC-MSCs-Exos alone was inconspicuous, a notable augmentation in effect ensued upon their combined application. Concomitantly, a marked reduction was observed in the expressionlevels of key enzymes including HK, PFK, PK, LDH, TNF-α, IL-1β, CAT, SOD and GSH-Px in the malignant hepatocytes, while IL-6 and MDA exhibited heightened expression. Pathway enrichment analysis underscored selenocompound metabolism and cysteine and methionine metabolism as pivotal pathways.

CONCLUSION

The potentiated efficacy of GA conjunction with hUC-MSCs-Exos may be attributed to their synergistic modulation of anti-inflammatory, antioxidant, and glycolytic functions, thereby influencing selenocompound metabolism and cysteine and methionine metabolism. This study reveals the efficacy and mechanism of Exos and GA combined therapy for hepatoma, providing new methods and ideas for the clinical treatment of hepatoma.

Ex Vivo Regional Gene Therapy Compared to Recombinant BMP-2 for the Treatment of Critical-Size Bone Defects: An In Vivo Single-Cell RNA-Sequencing Study

Ex vivo regional gene therapy is a promising tissue-engineering strategy for bone regeneration: osteogenic mesenchymal stem cells (MSCs) can be genetically modified to express an osteoinductive stimulus (e.g., bone morphogenetic protein-2), seeded onto an osteoconductive scaffold, and then implanted into a bone defect to exert a therapeutic effect. Compared to recombinant human BMP-2 (rhBMP-2), which is approved for clinical use, regional gene therapy may have unique benefits related to the addition of MSCs and the sustained release of BMP-2. However, the cellular and transcriptional mechanisms regulating the response to these two strategies for BMP-2 mediated bone regeneration are largely unknown. Here, for the first time, we performed single-cell RNA sequencing (10x Genomics) of hematoma tissue in six rats with critical-sized femoral defects that were treated with either regional gene therapy or rhBMP-2. Our unbiased bioinformatic analysis of 2393 filtered cells in each group revealed treatment-specific differences in their cellular composition, transcriptional profiles, and cellular communication patterns. Gene therapy treatment induced a more robust chondrogenic response, as well as a decrease in the proportion of fibroblasts and the expression of profibrotic pathways. Additionally, gene therapy was associated with an anti-inflammatory microenvironment; macrophages expressing canonical anti-inflammatory markers were more common in the gene therapy group. In contrast, pro-inflammatory markers were more highly expressed in the rhBMP-2 group. Collectively, the results of our study may offer insights into the unique pathways through which ex vivo regional gene therapy can augment bone regeneration compared to rhBMP-2. Furthermore, an improved understanding of the cellular pathways involved in segmental bone defect healing may allow for the further optimization of regional gene therapy or other bone repair strategies.

Translation Research in Therapeutic Approaches from Conventional to Novel Nano-therapeutics for Rheumatoid Arthritis Treatment

Rheumatoid arthritis is a systemic autoimmune disorder related to joint inflammation, bone erosion, and deformity. Numerous studies indicate that the causes and consequences of RA are still being debated, and therapeutic strategies are in the translation stage. Non-steroidal anti-inflammatory drugs continue to be often used to relieve pain. Still, due to their poor efficacy, failure to halt the spread of the disease, and undesirable adverse effects, they are no longer regarded as first-line treatments. The development of biologic DMRDs designed to reduce the inflammatory response led to substantial changes to the strategy for managing this disease. Although biologic DMRDs have made significant strides in the management of Rheumatoid arthritis, certain patients' lack of response to biological approaches and therapy cessation due to systemic toxicity are unresolved problems. Therefore, to improve the in vivo effect and reduce systemic adverse effects, new approaches are needed to proactively target and transport therapeutic molecules to target sites. The intriguing method of nanotechnology enables the encapsulation of drugs to prevent their deterioration and systemic adverse effects. The next generation of Rheumatoid arthritis therapies might be based on advances in nanomaterial-based drug delivery, Trojan horse, and antibody targeting approaches. This article presents an overview of the advancements in Rheumatoid arthritis therapy, ranging from traditional methods to recent cutting-edge, ongoing pre-clinical and clinical approaches.

Advancing immunomodulatory functions in mesenchymal stem/stromal cells through targeting the GATA6-mediated pathway

BACKGROUND AIMS

The immunomodulatory capacity of mesenchymal stem/stromal cells (MSCs) is a key feature that makes them particularly valuable for regenerative medicine. However, this potential is affected by the chronological aging of the donors and the cell expansion procedures in culture. We have demonstrated that GATA binding protein 6 (GATA6) plays a pivotal role in the aging of MSCs and inhibiting GATA6 rejuvenates the characteristics of MSCs.

METHODS

In this study, we compared the immunomodulatory capabilities of young and old MSC models, using induced pluripotent stem cells-derived rejuvenated MSCs (rMSCs) and their parental MSCs (pMSCs), respectively, to identify a key mechanism involved in the differential regulation of these capabilities. Additionally, we explored the role of GATA6 in mediating the mechanism.

RESULTS

Our results demonstrated that rMSCs exhibited downregulated aging-associated regulators, including p53, p21 and GATA6, and showed enhanced suppression of T cell proliferation compared to pMSCs. Through analyzing our previous RNA-seq data and employing target gene knockdown, we determined both suppressors of cytokine signaling 3 (SOCS3) and interleukin 6 were involved in GATA6-induced regulation, collectively affecting the expression of programmed death ligand 1 (PDL1) in both pMSCs and rMSCs.

CONCLUSIONS

Our findings underline the significance of the GATA6/SOCS3/PDL1 pathway in regulating aging-associated changes in MSC immunomodulatory activity, providing valuable insights into the potential use of rMSCs in the treatment of immune diseases and regenerative medicine.

The proliferation/migration ability mediated by CD151/PI3K/AKT pathway determines the therapeutic effect of hUC-MSCs transplantation on rheumatoid arthritis

OBJECTIVE

To elucidate the underlying mechanism by which the proliferation and migration abilities of human umbilical cord mesenchymal stem cells (hUC-MSCs) determine their therapeutic efficacy in rheumatoid arthritis treatment.

METHODS

The DBA/1J mice were utilized to establish a collagen-induced RA (CIA) mouse model and to validate the therapeutic efficacy of hUC-MSCs transfected with CD151 siRNA. RNA-seq, QT-PCR and western blotting were utilized to evaluate the mRNA and protein levels of the PI3K/AKT pathway, respectively.

RESULTS

IFN-γ significantly enhanced the proliferation and migration abilities of hUC-MSCs, up-regulating the expression of CD151, a gene related to cell proliferation and migration. Effective inhibition of this effect was achieved through CD151 siRNA treatment. However, IFN-γ did not affect hUC-MSCs differentiation or changes in cell surface markers. Additionally, transplantation of CD151-interfered hUC-MSCs (siRNA-CD151-hUC-MSCs) resulted in decreased colonization in the toes of CIA mice and worse therapeutic effects compared to empty vector treatment (siRNA-NC-hUC-MSCs).

CONCLUSION

IFN-γ facilitates the proliferation and migration of hUC-MSCs through the CD151/PI3K/AKT pathway. The therapeutic efficacy of siRNA-CD151-hUC-MSCs was found to be inferior to that of siRNA-NC-hUC-MSCs.

Mechanisms and Emerging Regulators of Neuroinflammation: Exploring New Therapeutic Strategies for Neurological Disorders

Neuroinflammation is a complex and dynamic response of the central nervous system (CNS) to injury, infection, and disease. While acute neuroinflammation plays a protective role by facilitating pathogen clearance and tissue repair, chronic and dysregulated inflammation contributes significantly to the progression of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis. This review explores the cellular and molecular mechanisms underlying neuroinflammation, focusing on the roles of microglia, astrocytes, and peripheral immune cells. Key signaling pathways, including NF-κB, JAK-STAT, and the NLRP3 inflammasome, are discussed alongside emerging regulators such as non-coding RNAs, epigenetic modifications, and the gut-brain axis. The therapeutic landscape is evolving, with traditional anti-inflammatory drugs like NSAIDs and corticosteroids offering limited efficacy in chronic conditions. Immunomodulators, gene and RNA-based therapeutics, and stem cell methods have all shown promise for more specific and effective interventions. Additionally, the modulation of metabolic states and gut microbiota has emerged as a novel strategy to regulate neuroinflammation. Despite significant progress, challenges remain in translating these findings into clinically viable therapies. Future studies should concentrate on integrated, interdisciplinary methods to reduce chronic neuroinflammation and slowing the progression of neurodegenerative disorders, providing opportunities for revolutionary advances in CNS therapies.

Targeted Therapy for Severe Sjogren's Syndrome: A Focus on Mesenchymal Stem Cells

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by the infiltration of lymphocytes on salivary and lacrimal glands, resulting in their dysfunction. Patients suffering from severe pSS have an increased risk of developing multi-organ dysfunction syndrome due to the development of systemic inflammatory response, which results in immune cell-driven injury of the lungs, kidneys, liver, and brain. Therapeutic agents that are used for the treatment of severe pSS encounter various limitations and challenges that can impact their effectiveness. Accordingly, there is a need for targeted, personalized therapy that could address the underlying detrimental immune response while minimizing side effects. Results obtained in a large number of recently published studies have demonstrated the therapeutic efficacy of mesenchymal stem cells (MSCs) in the treatment of severe pSS. MSCs, in a juxtacrine and paracrine manner, suppressed the generation of inflammatory Th1 and Th17 lymphocytes, induced the expansion of immunosuppressive cells, impaired the cross-talk between auto-reactive T and B cells, and prevented the synthesis and secretion of auto-antibodies. Additionally, MSC-derived growth and trophic factors promoted survival and prevented apoptosis of injured cells in inflamed lacrimal and salivary glands, thereby enhancing their repair and regeneration. In this review article, we summarized current knowledge about the molecular mechanisms that are responsible for the beneficial effects of MSCs in the suppression of immune cell-driven injury of exocrine glands and vital organs, paving the way for a better understanding of their therapeutic potential in the targeted therapy of severe pSS.

Multiomics analyses reveal adipose-derived stem cells inhibit the inflammatory response of M1-like macrophages through secreting lactate

BACKGROUND

Adipose-derived stem cells (ADSCs) are widely used in the field of regenerative medicine because of their various functions, including anti-inflammatory effects. ADSCs are considered to exert their anti-inflammatory effects by secreting anti-inflammatory cytokines and extracellular vesicles. Although recent studies have reported that metabolites have a variety of physiological activities, whether those secreted by ADSCs have anti-inflammatory properties remains unclear. Here, we performed multiomics analyses to examine the effect of ADSC-derived metabolites on M1-like macrophages, which play an important role in inflammatory responses.

METHODS

The concentration of metabolites in the culture supernatant of ADSCs was quantified using capillary electrophoresis time-of-flight mass spectrometry. To evaluate their effects on inflammatory responses, M1-like macrophages were exposed to the conditioned ADSC medium or their metabolites, and RNA sequencing was used to detect gene expression changes. Immunoblotting was performed to examine how the metabolite suppresses inflammatory processes. To clarify the contribution of the metabolite in the conditioned medium to its anti-inflammatory effects, metabolite uptake was pharmacologically inhibited, and gene expression and the tumor necrosis factor-α concentration were measured by quantitative PCR and enzyme-linked immunosorbent assay, respectively.

RESULTS

Metabolomic analysis showed large amounts of lactate in the culture supernatant. The conditioned medium and lactate significantly suppressed or increased the pro-inflammatory and anti-inflammatory gene expressions. However, sequencing and immunoblotting analysis revealed that lactate did not induce polarization from M1- to M2-like macrophages. Based on a recent report that the immunosuppressive effect of lactate depends on epigenetic reprogramming, histone acetylation was investigated, and H3K27ac expression was upregulated. In addition, 7ACC2, which specifically inhibits the monocarboxylate transporter 1, significantly inhibited the anti-inflammatory effect of the conditioned ADSC medium on M1-like macrophages.

CONCLUSIONS

Our results showed that ADSCs suppress pro-inflammatory effects of M1-like macrophages by secreting lactate. This study adds to our understanding of the importance of metabolites and is also expected to elucidate new mechanisms of ADSC treatments.

Exosome-based therapies for inflammatory disorders: a review of recent advances

Exosomes, small extracellular vesicles secreted by cells, have emerged as focal mediators in intercellular communication and therapeutic interventions across diverse biomedical fields. Inflammatory disorders, including inflammatory bowel disease, acute liver injury, lung injury, neuroinflammation, and myocardial infarction, are complex conditions that require innovative therapeutic approaches. This review summarizes recent advances in exosome-based therapies for inflammatory disorders, highlighting their potential as diagnostic biomarkers and therapeutic agents. Exosomes have shown promise in reducing inflammation, promoting tissue repair, and improving functional outcomes in preclinical models of inflammatory disorders. However, further research is needed to overcome the challenges associated with exosome isolation, characterization, and delivery, as well as to fully understand their mechanisms of action. Current limitations and future directions in exosome research underscore the need for enhanced isolation techniques and deeper mechanistic insights to harness exosomes' full therapeutic potential in clinical applications. Despite these challenges, exosome-based therapies hold great potential for the treatment of inflammatory disorders and may offer a new paradigm for personalized medication.

Effect of cigarette smoke on the proliferation, viability, gene expression, and cellular functions of adipose-derived mesenchymal stem cells from smoking and non-smoking donors

Cigarette smoking negatively impacts mesenchymal stem cell functionality, including proliferation, viability, and differentiation potential. Adipose-derived mesenchymal stem cells (ADMSCs) are increasingly used for therapeutic purposes, but the specific effects of smoking in vivo on these cells are poorly understood. This study investigates the effects of cigarette smoke on the proliferation, viability, gene expression, and cellular functions of ADMSCs from smoking and non-smoking donors. In this study, ADMSCs were isolated from healthy smokers and non-smokers, and cell proliferation was assessed using the MTT assay, viability with apoptosis assays, mitochondrial membrane potential (MMP), and gene expression related to oxidative stress and cellular functions. Cell cycle analysis was also conducted. Our findings reveal a significant decrease in the proliferation of ADMSCs from smokers. Apoptosis assays showed reduced viable cells in smokers without a significant change in MMP, suggesting alternative pathways contributing to decreased viability. Gene expression analysis indicated the upregulation of genes associated with oxidative stress response and cellular defense mechanisms and the downregulation of genes related to inflammatory signaling, detoxification, and cellular metabolism. Cell cycle analysis indicates cycle arrest or delay in smokers, possibly due to stress and potential DNA damage. Smoking negatively affects ADMSCs' proliferation, viability, and function through oxidative stress and gene expression alterations. These findings highlight the importance of considering smoking status in ADMSC therapies and the need for further research to mitigate the effect of smoking on stem cells.

Anti-necroptotic effects of human Wharton's jelly-derived mesenchymal stem cells in skeletal muscle cell death model via secretion of GRO-α

Human mesenchymal stem cells (hMSCs) have therapeutic applications and potential for use in regenerative medicine. However, the use of hMSCs in research and clinical medicine is limited by a lack of information pertaining to their donor-specific functional attributes. In this study, we compared the characteristics of same-donor derived placenta (PL) and Wharton's jelly (WJ)-derived hMSCs, we also compared their mechanism of action in a skeletal muscle disease in vitro model. The same-donor-derived hWJ- and hPL-MSCs exhibited typical hMSC characteristics. However, GRO-α was differentially expressed in hWJ- and hPL-MSCs. hWJ-MSCs, which secreted a high amount of GRO-α, displayed a higher ability to inhibit necroptosis in skeletal muscle cells than hPL-MSCs. This demonstrates the anti-necroptotic therapeutic effect of GRO-α in the skeletal muscle cell death model. Furthermore, GRO-α also exhibited the anti-necroptotic effect in a Duchenne muscular dystrophy (DMD) mouse model. Considering their potential to inhibit necroptosis in skeletal muscle cells, hWJ-MSCs and the derived GRO-α are novel treatment options for skeletal muscle diseases such as DMD.

Scaffold-free 3D culture systems for stem cell-based tissue regeneration

Recent advances in scaffold-free three-dimensional (3D) culture methods have significantly enhanced the potential of stem cell-based therapies in regenerative medicine. This cutting-edge technology circumvents the use of exogenous biomaterial and prevents its associated complications. The 3D culture system preserves crucial intercellular interactions and extracellular matrix support, closely mimicking natural biological niches. Therefore, stem cells cultured in 3D formats exhibit distinct characteristics, showcasing their capabilities in promoting angiogenesis and immunomodulation. This review aims to elucidate foundational technologies and recent breakthroughs in 3D scaffold-free stem cell engineering, offering comprehensive guidance for researchers to advance this technology across various clinical applications. We first introduce the various sources of stem cells and provide a comparative analysis of two-dimensional (2D) and 3D culture systems. Given the advantages of 3D culture systems, we delve into the specific fabrication and harvesting techniques for cell sheets and spheroids. Furthermore, we explore their applications in pre-clinical studies, particularly in large animal models and clinical trials. We also discuss multidisciplinary strategies to overcome existing limitations such as insufficient efficacy, hostile microenvironments, and the need for scalability and standardization of stem cell-based products.

Efficacy and safety of stem cell therapy for fistula management: an overview of existing systematic reviews

BACKGROUND

Fistulas, abnormal connections between two anatomical structures, significantly impact the quality of life and can result from a variety of causes, including congenital defects, inflammatory conditions, and surgical complications. Stem cell therapy has emerged as a promising alternative due to its potential for regenerative and immunomodulatory effects. This overview of systematic reviews aimed to assess the safety and efficacy of stem cell therapy in managing fistulas, drawing on the evidence available.

METHODS

This umbrella review was conducted following the Joanna Briggs Institute (JBI) methodology to assess the efficacy and safety of stem cell therapy for treating various types of fistulas. A comprehensive search was performed across multiple electronic databases including PubMed, Embase, Cochrane Register, and Web of Science up to 5 May 2024. Systematic reviews focusing on stem cell therapy for fistulas were included, with data extracted on study design, stem cell types, administration methods, and outcomes. The quality of the reviews was assessed using the AMSTAR 2 tool, and meta-analyses were conducted using R software version 4.3.

RESULTS

Nineteen systematic reviews were included in our umbrella review. The stem cell therapy demonstrated by significant improvements in clinical remission rates, with a relative risk (RR) of 1.299 (95% CI: 1.192-1.420). Stem cell therapy enhanced fistula closure rates, both short-term (RR=1.481; 95% CI: 1.036-2.116) and long-term (RR=1.422; 95% CI: 1.091-1.854). The safety analysis revealed no significant increase in the risk of adverse events with stem cell therapy, showing a pooled RR of 0.972 (95% CI: 0.739-1.278) for general adverse events and 1.136 (95% CI: 0.821-1.572) for serious adverse events, both of which indicate a safety profile comparable to control treatments. Re-epithelialization rates also improved (RR=1.44; 95% CI: 1.322-1.572).

CONCLUSION

Stem cell therapy shows promise as an effective and safe treatment for fistulas, particularly in inducing remission and promoting closure of complex fistulas. The findings advocate for further high-quality research to confirm these benefits and potentially incorporate stem cell therapy into standard clinical practice for fistula management. Future studies should focus on long-term outcomes and refining stem cell treatment protocols to optimize therapeutic efficacy.

Revolutionizing medicine: recent developments and future prospects in stem-cell therapy

Stem-cell therapy is a revolutionary frontier in modern medicine, offering enormous capacity to transform the treatment landscape of numerous debilitating illnesses and injuries. This review examines the revolutionary frontier of treatments utilizing stem cells, highlighting the distinctive abilities of stem cells to undergo regeneration and specialized cell differentiation into a wide variety of phenotypes. This paper aims to guide researchers, physicians, and stakeholders through the intricate terrain of stem-cell therapy, examining the processes, applications, and challenges inherent in utilizing stem cells across diverse medical disciplines. The historical journey from foundational contributions in the late 19th and early 20th centuries to recent breakthroughs, including ESC isolation and iPSC discovery, has set the stage for monumental leaps in medical science. Stem cells' regenerative potential spans embryonic, adult, induced pluripotent, and perinatal stages, offering unprecedented therapeutic opportunities in cancer, neurodegenerative disorders, cardiovascular ailments, spinal cord injuries, diabetes, and tissue damage. However, difficulties, such as immunological rejection, tumorigenesis, and precise manipulation of stem-cell behavior, necessitate comprehensive exploration and innovative solutions. This manuscript summarizes recent biotechnological advancements, critical trial evaluations, and emerging technologies, providing a nuanced understanding of the triumphs, difficulties, and future trajectories in stem cell-based regenerative medicine. Future directions, including precision medicine integration, immune modulation strategies, advancements in gene-editing technologies, and bioengineering synergy, offer a roadmap in stem cell treatment. The focus on stem-cell therapy's potential highlights its significant influence on contemporary medicine and points to a future in which individualized regenerative therapies will alleviate various medical disorders.

Roles of extracellular vesicles from mesenchymal stem cells in regeneration

Mesenchymal stem cells (MSCs) are highly valued in regenerative medicine due to their ability to self-renew and differentiate into various cell types. Their therapeutic benefits are primarily due to their paracrine effects, in particular through extracellular vesicles (EVs), which are related to intercellular communication. Recent advances in EV production and extraction technologies highlight the potential of MSC-derived EVs (MSC-EVs) in tissue engineering and regenerative medicine. MSC-EVs offer several advantages over traditional cell therapies, including reduced toxicity and immunogenicity compared with whole MSCs. EVs carrying functional molecules such as growth factors, cytokines, and miRNAs play beneficial roles in tissue repair, fibrosis treatment, and scar prevention by promoting angiogenesis, skin cell migration, proliferation, extracellular matrix remodeling, and reducing inflammation. Despite the potential of MSC-EVs, there are several limitations to their use, including variability in quality, the need for standardized methods, low yield, and concerns about the composition of EVs and the potential risks. Overall, MSC-EVs are a promising alternative to cell-based therapies, and ongoing studies aim to understand their actions and optimize their use for better clinical outcomes in wound healing and skin regeneration.

Efficacy and safety of human umbilical cord-derived mesenchymal stem cells versus placebo added to second-line therapy in patients with steroid-refractory acute graft-versus-host disease: a multicentre, randomized, double-blind, phase 2 trial

BACKGROUND

Failure of systemic corticosteroid therapy is common in patients with newly diagnosed acute graft-versus-host disease (aGVHD) above grade II. Mesenchymal stem cells (MSCs) have been used as a tolerable and potentially effective second-line therapy for steroid-refractory aGVHD (SR-aGVHD); however, well-designed, prospective, controlled studies are lacking.

METHODS

This multicentre, randomized, double-blind, placebo-controlled, exploratory phase 2 study enrolled patients with SR-aGVHD above grade II from 7 centres. Patients were randomized 1:1 to receive umbilical cord-derived MSCs or placebo added to one centre's choice of second-line agents (except for ruxolitinib). The agents were infused twice weekly. Patients with complete response (CR), no response (NR), or progression of disease (PD) at d28 received 8 infusions, and those with partial response (PR) received the above infusions for another 4 weeks. The per-protocol population consisted of patients who received ≥ 8 infusions. The primary endpoint was the overall response rate (ORR, CR + PR) at d28, analyzed in the per-protocol and intention-to-treat populations.

RESULTS

Seventy-eight patients (median age 38, range 13-62) were enrolled: 40 in the MSC group and 38 in the control. Patients in the MSC group received a median of 8 doses, with a median response time of 14 days. In intention-to-treat analysis, ORR at d28 was 60% for MSC group and 50% for control group (p = 0.375). The 2-year cumulative incidence of moderate to severe cGVHD was marginally lower in the MSC group than in the control (13.8% vs. 39.8%, p = 0.067). The 2-year failure-free survival was similar between the MSC and control groups (52.5% vs. 44.4%, p = 0.43). In per-protocol analysis (n = 62), ORR at d28 was significantly greater in the MSC group than in the control group (71.9% vs. 46.7%, p = 0.043). Among patients with gut involvement, ORR at d28 was significantly greater in the MSC group than in the control (66.7% vs. 33.3%, p = 0.031). The adverse events incidences were similar between groups.

CONCLUSIONS

In this exploratory study, there was no superior ORR at d28 demonstrated in the MSC group compared with the control. However, MSCs showed a gradual treatment effect at a median of 2 weeks. Patients who completed 8 infusions may benefit from adding MSCs to one conventional second-line agent, especially those with gut involvement. MSCs was well tolerated in patients with SR-aGVHD.

TRIAL REGISTRATION

chictr.org.cn ChiCTR2000035740.

Therapeutic potential and mechanisms of stem cells in major depressive disorder: a comprehensive review

Depression is a common affective disorder characterized by persistent low mood, diminished interest or pleasure in normally enjoyable activities, disturbances in sleep patterns, and suicidal ideation. Conventional treatments often yield unsatisfactory results and are associated with several adverse effects. However, emerging literature has highlighted the potential of stem cell (SC) transplantation as a promising avenue for treating depression owing to its favorable anti-inflammatory and neurotrophic properties. This review summarizes the therapeutic effects and underlying mechanisms associated with SC transplantation in depression, offering a conceptual framework for the future application of SCs in the clinical treatment of depression.

Extracellular Vesicles: A Novel Diagnostic Tool and Potential Therapeutic Approach for Equine Osteoarthritis

Osteoarthritis (OA) is a chronic progressive degenerative joint disease that affects a significant portion of the equine population and humans worldwide. Current treatment options for equine OA are limited and incompletely curative. Horses provide an excellent large-animal model for studying human OA. Recent advances in the field of regenerative medicine have led to the exploration of extracellular vesicles (EVs)-cargoes of microRNA, proteins, lipids, and nucleic acids-to evaluate their diagnostic value in terms of disease progression and severity, as well as a potential cell-free therapeutic approach for equine OA. EVs transmit molecular signals that influence various biological processes, including the inflammatory response, apoptosis, proliferation, and cell communication. In the present review, we summarize recent advances in the isolation and identification of EVs, the use of their biologically active components as biomarkers, and the distribution of the gap junction protein connexin 43. Moreover, we highlight the role of mesenchymal stem cell-derived EVs as a potential therapeutic tool for equine musculoskeletal disorders. This review aims to provide a comprehensive overview of the current understanding of the pathogenesis, diagnosis, and treatment strategies for OA. In particular, the roles of EVs as biomarkers in synovial fluid, chondrocytes, and plasma for the early detection of equine OA are discussed.

The role of mitochondrial transfer in the suppression of CD8+ T cell responses by Mesenchymal stem cells

BACKGROUND

. CD8+ Cytotoxic T lymphocytes play a key role in the pathogenesis of autoimmune diseases and clinical conditions such as graft versus host disease and graft rejection. Mesenchymal Stromal Cells (MSCs) are multipotent cells with tissue repair and immunomodulatory capabilities. Since they are able to suppress multiple pathogenic immune responses, MSCs have been proposed as a cellular therapy for the treatment of immune-mediated diseases. However, the mechanisms underlying their immunosuppressive properties are not yet fully understood. MSCs have the remarkable ability to sense tissue injury and inflammation and respond by donating their own mitochondria to neighboring cells. Whether mitochondrial transfer has any role in the repression of CD8+ responses is unknown.

METHODS AND RESULTS

. We have utilized CD8+ T cells from Clone 4 TCR transgenic mice that differentiate into effector cells upon activation in vitro and in vivo to address this question. Allogeneic bone marrow derived MSCs, co-cultured with activated Clone 4 CD8+ T cells, decreased their expansion, the production of the effector cytokine IFNγ and their diabetogenic potential in vivo. Notably, we found that during this interaction leading to suppression, MSCs transferred mitochondria to CD8+ T cells as evidenced by FACS and confocal microscopy. Transfer of MSC mitochondria to Clone 4 CD8+ T cells also resulted in decreased expansion and production of IFNγ upon activation. These effects overlapped and were additive with those of prostaglandin E2 secreted by MSCs. Furthermore, preventing mitochondrial transfer in co-cultures diminished the ability of MSCs to inhibit IFNγ production. Finally, we demonstrated that both MSCs and MSC mitochondria downregulated T-bet and Eomes expression, key transcription factors for CTL differentiation, on activated CD8+ T cells.

CONCLUSION

. In this report we showed that MSCs are able to interact with CD8+ T cells and transfer them their mitochondria. Mitochondrial transfer contributed to the global suppressive effect of MSCs on CD8+ T cell activation by downregulating T-bet and Eomes expression resulting in impaired IFNγ production of activated CD8+ T cells.

Unveiling the immunogenicity of allogeneic mesenchymal stromal cells: Challenges and strategies for enhanced therapeutic efficacy

Mesenchymal stromal cells (MSCs) exhibit significant potential in the context of cell therapy because of their capacity to perform a range of interconnected functions in damaged tissues, including immune modulation, hematopoietic support, and tissue regeneration. MSCs are hypoimmunogenic because of their diminished expression of major histocompatibility molecules, absence of costimulatory molecules, and presence of coinhibitory molecules. While autologous MSCs reduce the risk of rejection and infection, variability in cell numbers and proliferation limits their potential applications. Conversely, allogeneic MSCs (allo-MSCs) possess broad clinical applications unconstrained by donor physiology. Nonetheless, preclinical and clinical investigations highlight that transplanted allo-MSCs are subject to immune attack from recipients. These cells exhibit anti-inflammatory and proinflammatory phenotypes contingent on the microenvironment. Notably, the proinflammatory phenotype features enhanced immunogenicity and diminished immunosuppression, potentially triggering allogeneic immune reactions that impede long-term clinical efficacy. Consequently, preserving the low immunogenicity of allo-MSCs in vivo and mitigating immune rejection in diverse microenvironments represent crucial challenges for the widespread clinical application of MSCs. In this review, we elucidate the immune regulation of allo-MSCs, specifically focusing on two distinct subgroups, MSC1 and MSC2, that exhibit varying polarization states and immunogenicity. We discuss the factors and underlying mechanisms that induce MSC immunogenicity and polarization, highlighting the crucial role of major histocompatibility complex class I/II molecules in rejection post-transplantation. Additionally, we summarize the immunogenic regulatory targets and applications of allo-MSCs and outline strategies to address challenges in this promising field, aiming to enhance allo-MSC therapeutic efficacy for patients.

Current Therapeutic Strategies of Intervertebral Disc Regenerative Medicine

Intervertebral disc degeneration (IDD) is one of the most frequent causes of low back pain. No treatment is currently available to delay the progression of IDD. Conservative treatment or surgical interventions is only used to target the symptoms of IDD rather than treat the underlying cause. Currently, numerous potential therapeutic strategies are available, including molecular therapy, gene therapy, and cell therapy. However, the hostile environment of degenerated discs is a major problem that has hindered the clinical applicability of such approaches. In this regard, the design of drugs using alternative delivery systems (macro-, micro-, and nano-sized particles) may resolve this problem. These can protect and deliver biomolecules along with helping to improve the therapeutic effect of drugs via concentrating, protecting, and prolonging their presence in the degenerated disc. This review summarizes the research progress of diagnosis and the current options for treating IDD.

The landscape of new therapeutic opportunities for IBD

This chapter presents an overview of the emerging strategies to address the unmet needs in the management of inflammatory bowel diseases (IBD). IBD poses significant challenges, as over half of patients experience disease progression despite interventions, leading to irreversible complications, and a substantial proportion do not respond to existing therapies, such as biologics. To overcome these limitations, we describe a diverse array of novel therapeutic approaches. In the area of immune homeostasis restoration, the focus is on targeting cytokine networks, leukocyte trafficking, novel immune pathways, and cell therapies involving regulatory T cells and mesenchymal stem cells (MSC). Recognizing the critical role of impaired intestinal barrier integrity in IBD, we highlight therapies aimed at restoring barrier function and promoting mucosal healing, such as those targeting cell proliferation, tight junctions, and lipid mediators. Addressing the challenges posed by fibrosis and fistulas, we describe emerging targets for reversing fibrosis like kinase and cytokine inhibitors and nuclear receptor agonists, as well as the potential of MSC for fistulas. The restoration of a healthy gut microbiome, through strategies like fecal microbiota transplantation, rationally defined bacterial consortia, and targeted antimicrobials, is also highlighted. We also describe innovative approaches to gut-targeted drug delivery to enhance efficacy and minimize side effects. Reinforcing these advancements is the critical role of precision medicine, which emphasizes the use of multiomics analysis for the discovery of biomarkers to enable personalized IBD care. Overall, the emerging landscape of therapeutic opportunities for IBD holds great potential to surpass the therapeutic ceiling of current treatments.

The Use of Mesenchymal Stromal/Stem Cells (MSC) for Periodontal and Peri-implant Regeneration: Scoping Review

The necessity for regenerating peri-implant and periodontal tissues is increasingly apparent. Periodontal diseases can result in a significant loss of clinical attachment level, and tissue regeneration stands as the ultimate goal of periodontal therapy. With the rise of osseointegration, the prosthetic rehabilitation of missing teeth using dental implants has surged, leading to a frequent need for alveolar bone regeneration around implants. This review assessed studies reporting various sources of mesenchymal stromal/stem cells (MSC) and their potential in regenerating periodontal and peri-implant bone tissue. A search was conducted across seven databases spanning the past decade. Three authors independently screened all identified titles and abstracts for eligibility, generating tables to summarize included studies in animals and humans separately. A total of 55 articles were chosen for final evaluation, showcasing five origins of MSC used in humans and animals for regenerating periodontal tissues and peri-implant bone, using different types of scaffolds. Overall, research from the past decades supports the effectiveness of MSC in promoting periodontal and peri-implant regeneration. However, the impact of MSC on regenerative therapies in humans is still in its initial stages. Future research should optimize MSC application protocols by combining techniques, such as the use of nanomedicine and 3D printing for tissue engineering. Clinical studies should also understand the long-term effects and compare MSC therapies with current treatment modalities. By addressing these areas, the scientific community can ensure that MSC therapies are both safe and effective, ultimately enhancing therapeutic strategies and treatment outcomes in Periodontology and Implantology.

Current and emerging therapeutic strategies for perianal fistula in Crohn's disease patients

The long-term remission rates achieved with current treatment options for Crohn's disease with perianal fistula (CD-PAF)-including antibiotics, biologics, immunomodulators, and Janus kinase inhibitors, often combined with advanced surgical interventions-remain unsatisfactory. This chapter explores several innovative biomaterials-based solutions, such as plugs, adhesives, fillers, and stem cell-based therapies. The key approaches and treatment outcomes of these advanced therapies are examined, focusing on their ability to modulate the immune response, promote tissue healing, and improve patient outcomes. Additionally, the chapter discusses future directions, including the optimization of biomaterial designs, enhancement of delivery and retention of regenerative therapies, and a deeper understanding of the underlying mechanisms of healing.

Mesenchymal Stem Cells and Tissue Bioengineering Applications in Sheep as Ideal Model

The most common technologies in tissue engineering include growth factor therapies; metal implants, such as titanium; 3D bioprinting; nanoimprinting for ceramic/polymer scaffolds; and cell therapies, such as mesenchymal stem cells (MSCs). Cell therapy is a promising alternative to organ grafts and transplants in the treatment of numerous musculoskeletal diseases. MSCs have increasingly been used in generative medicine due to their specialized self-renewal, immunomodulation, multiplication, and differentiation properties. To further expand the potential of these cells in tissue repair, significant efforts are currently dedicated to the production of biomaterials with desirable short- and long-term biophysical properties that can aid the differentiation and expansion of MSCs. Biomaterials support MSC differentiation by modulating their characteristics, such as composition, mechanical properties, porosity, and topography. This review aimed to describe recent MSC approaches, including those associated with biomaterials, from experimental, clinical, and preclinical studies with sheep models.

Extracellular vesicles as therapeutic tools in regenerative dentistry

Dental and maxillofacial diseases are always accompanied by complicated hard and soft tissue defects, involving bone, teeth, blood vessels and nerves, which are difficult to repair and severely affect the life quality of patients. Recently, extracellular vesicles (EVs) secreted by all types of cells and extracted from body fluids have gained more attention as potential solutions for tissue regeneration due to their special physiological characteristics and intrinsic signaling molecules. Compared to stem cells, EVs present lower immunogenicity and tumorigenicity, cause fewer ethical problems, and have higher stability. Thus, EV therapy may have a broad clinical application in regenerative dentistry. Herein, we reviewed the currently available literature regarding the functional roles of EVs in oral and maxillofacial tissue regeneration, including in maxilla and mandible bone, periodontal tissues, temporomandibular joint cartilage, dental hard tissues, peripheral nerves and soft tissues. We also summarized the underlying mechanisms of actions of EVs and their delivery strategies for dental tissue regeneration. This review would provide helpful guidelines and valuable insights into the emerging potential of EVs in future research and clinical applications in regenerative dentistry.

Stimuli-Responsive Substrates to Control the Immunomodulatory Potential of Stromal Cells

Mesenchymal stromal cells (MSCs) have broad immunomodulatory properties that range from regulation, proliferation, differentiation, and immune cell activation to secreting bioactive molecules that inhibit inflammation and regulate immune response. These properties provide MSCs with high therapeutic potency that has been shown to be relevant to tissue engineering and regenerative medicine. Hence, researchers have explored diverse strategies to control the immunomodulatory potential of stromal cells using polymeric substrates or scaffolds. These substrates alter the immunomodulatory response of MSCs, especially through biophysical cues such as matrix mechanical properties. To leverage these cell-matrix interactions as a strategy for priming MSCs, emerging studies have explored the use of stimuli-responsive substrates to enhance the therapeutic value of stromal cells. This review highlights how stimuli-responsive materials, including chemo-responsive, microenvironment-responsive, magneto-responsive, mechano-responsive, and photo-responsive substrates, have specifically been used to promote the immunomodulatory potential of stromal cells by controlling their secretory activity.

Engineered Mesenchymal Stem Cells as Treatment for Cancers: Opportunities, Clinical Applications and Challenges

The insufficient and unspecific target of classical chemotherapies often leads to therapy resistance and cancer recurrence. Over the past decades, discoveries about mesenchymal stem cell (MSC) biology have provided new potential approaches to improve cancer therapy. Researchers have utilised the multipotent, regenerative and immunosuppressive qualities of MSCs and tropisms towards inflammatory, hypoxic and malignant sites in various therapeutic applications. Although MSC-based therapies have generally been demonstrated safe, their effectiveness remains limited when these cells are used alone. However, through genetic engineering, researchers have proven that MSCs can be modified to have specialised delivery roles to increase their therapeutic efficacy in cancer treatment. They can be made to overexpress therapeutic proteins through viral or non-viral genetic modification, which enhances their innate properties. Nevertheless, these engineering strategies must be optimised to increase therapeutic efficacy and targeting effectiveness while minimising any loss of MSC function. This review underscores the cutting-edge methods for engineering MSCs, discusses their promise and the difficulties in translating them into clinical settings, and offers some prospective suggestions for the future on achieving their full therapeutic potential.