Novel lipid mediator 7S,14R-docosahexaenoic acid: biogenesis and harnessing mesenchymal stem cells to ameliorate diabetic mellitus and retinal pericyte loss

Introduction: Stem cells can be used to treat diabetic mellitus and complications. ω3-docosahexaenoic acid (DHA) derived lipid mediators are inflammation-resolving and protective. This study found novel DHA-derived 7S,14R-dihydroxy-4Z,8E,10Z,12E,16Z,19Z-docosahexaenoic acid (7S,14R-diHDHA), a maresin-1 stereoisomer biosynthesized by leukocytes and related enzymes. Moreover, 7S,14R-diHDHA can enhance mesenchymal stem cell (MSC) functions in the amelioration of diabetic mellitus and retinal pericyte loss in diabetic db/db mice. Methods: MSCs treated with 7S,14R-diHDHA were delivered into db/db mice i.v. every 5 days for 35 days. Results: Blood glucose levels in diabetic mice were lowered by 7S,14R-diHDHA-treated MSCs compared to control and untreated MSC groups, accompanied by improved glucose tolerance and higher blood insulin levels. 7S,14R-diHDHA-treated MSCs increased insulin+ β-cell ratio and decreased glucogan+ α-cell ratio in islets, as well as reduced macrophages in pancreas. 7S,14R-diHDHA induced MSC functions in promoting MIN6 β-cell viability and insulin secretion. 7S,14R-diHDHA induced MSC paracrine functions by increasing the generation of hepatocyte growth factor and vascular endothelial growth factor. Furthermore, 7S,14R-diHDHA enhanced MSC functions to ameliorate diabetes-caused pericyte loss in diabetic retinopathy by increasing their density in retina in db/db mice. Discussion: Our findings provide a novel strategy for improving therapy for diabetes and diabetic retinopathy using 7S,14R-diHDHA-primed MSCs.

Autophagy of umbilical cord mesenchymal stem cells induced by rapamycin conduces to pro-angiogenic function of the conditioned medium

Angiogenesis is critical for wound healing and tissue repair. Umbilical cord mesenchymal stem cells (UCMSCs)-conditioned medium has certain actions to promote angiogenesis, and is expected for wound healing and tissue repair. However, recent studies showed that the pro-angiogenic efficacy of unprocessed MSCs-conditioned medium is low, and insufficient for tissue repair. Autophagy is a process for protein recycling and a contributor for cell exocrine, which may enhance pro-angiogenic efficacy of the conditioned medium by stimulating cytokine release from UCMSCs. Therefore, in this study we attempted to obtain enhanced autophagy in UCMSCs using different concentrations of rapamycin and compared pro-angiogenic functions of the conditioned media. The in vitro data showed that although 100 nM-10 μM rapamycin all could induce autophagy in UCMSCs, 100 nM was the best dose to optimize the angiogenic effect of the conditioned medium. The in vivo data also showed that pro-angiogenic effect of the optimized conditioned medium was more obvious than that of the control conditioned medium (0 nM group) in the injected matrigel plaques. Further, the expressions of VEGF, FGF-2, MMP-9, PDGF-α and PDGF-β were markedly increased in UCMSCs treated with 100 nM rapamycin. In conclusion, appropriately enhancing autophagy of UCMSC can improve pro-angiogenic efficacy of the conditioned medium, which may optimize therapeutic applications of UCMSCs-conditioned medium in wound healing and tissue repair.

New insights in application of mesenchymal stem cells therapy in tumor microenvironment: pros and cons

Multipotent mesenchymal stem cells (MSCs) are widely accepted as a useful tool for cell-based therapy of various diseases including malignancies. The therapeutic effects of MSCs are mainly attributed to their immunomodulatory and immunosuppressive properties. Despite the promising outcomes of MSCs in cancer therapy, a growing body of evidence implies that MSCs also show tumorigenic properties in the tumor microenvironment (TME), which might lead to tumor induction and progression. Owing to the broad-spectrum applications of MSCs, this challenge needs to be tackled so that they can be safely utilized in clinical practice. Herein, we review the diverse activities of MSCs in TME and highlight the potential methods to convert their protumorigenic characteristics into onco-suppressive effects.

Chimeric Peptide Engineered Bioregulator for Metastatic Tumor Immunotherapy through Macrophage Polarization and Phagocytosis Restoration

Tumor-associated macrophages (TAMs) are the most abundant immune cells in solid tumor tissues, which restrict antitumor immunity by releasing tumor-supporting cytokines and attenuating phagocytosis behaviors. In this work, a chimeric peptide engineered bioregulator (ChiP-RS) is constructed for tumor immunotherapy through macrophage polarization and phagocytosis restoration. ChiP-RS is fabricated by utilizing macrophage-targeting chimeric peptide (ChiP) to load Toll-like receptor agonists (R848) and Src homology 2 (SH2) domain-containing protein tyrosine phosphatase 2 (SHP-2) inhibitor (SHP099). Among which, ChiP-RS prefers to be internalized by TAMs, repolarizing M2 macrophages into M1 macrophages to reverse the immunosuppressive microenvironment. In addition, SHP-2 can be downregulated to promote phagocytotic elimination behaviors of M1 macrophages, which will also activate T cell-based antitumor immunity for metastatic tumor therapy. In vitro and in vivo findings demonstrate a superior suppression effect of ChiP-RS against metastatic tumors without systemic side effects. Such a simple but effective nanoplatform provides sophisticated synergism for immunotherapy, which may facilitate the development of translational nanomedicine for metastatic tumor treatment.

A Worldwide Analysis of Adipose-Derived Stem Cells and Stromal Vascular Fraction in Orthopedics: Current Evidence and Applications

The biological enhancement of tissue regeneration and healing is an appealing perspective in orthopedics. We aimed to conduct a systematic review to describe the global distribution of studies investigating the use of adipose tissue derivates in orthopedics and to provide information on their quality and on the products available. The quality of the included studies was assessed using the modified Coleman Methodology Score (mCMS) and the Cochrane risk-of-bias tool for randomized trials. Eighty-two studies were included, with a total of 3594 patients treated. In total, 70% of the studies investigated the treatment of knee disorders, predominantly osteoarthritis; 26% of all studies dealt with expanded adipose-derived stem/stromal cells (ADSCs), 72% of which had stromal vascular fraction (SVF); 70% described the injection of adipose tissue derivates into the affected site; and 24% described arthroscopies with the addition of adipose tissue derivates. The mean mCMS for all studies was 51.7 ± 21.4 points, with a significantly higher score for the studies dealing with expanded ADSCs compared to those dealing with SVF (p = 0.0027). Our analysis shows high heterogeneity in terms of the types of performed procedures as well as the choice and processing of adipose tissue derivates.

Retinal Prostheses: Engineering and Clinical Perspectives for Vision Restoration

A retinal prosthesis, also known as a bionic eye, is a device that can be implanted to partially restore vision in patients with retinal diseases that have resulted in the loss of photoreceptors (e.g., age-related macular degeneration and retinitis pigmentosa). Recently, there have been major breakthroughs in retinal prosthesis technology, with the creation of numerous types of implants, including epiretinal, subretinal, and suprachoroidal sensors. These devices can stimulate the remaining cells in the retina with electric signals to create a visual sensation. A literature review of the pre-clinical and clinical studies published between 2017 and 2023 is conducted. This narrative review delves into the retinal anatomy, physiology, pathology, and principles underlying electronic retinal prostheses. Engineering aspects are explored, including electrode-retina alignment, electrode size and material, charge density, resolution limits, spatial selectivity, and bidirectional closed-loop systems. This article also discusses clinical aspects, focusing on safety, adverse events, visual function, outcomes, and the importance of rehabilitation programs. Moreover, there is ongoing debate over whether implantable retinal devices still offer a promising approach for the treatment of retinal diseases, considering the recent emergence of cell-based and gene-based therapies as well as optogenetics. This review compares retinal prostheses with these alternative therapies, providing a balanced perspective on their advantages and limitations. The recent advancements in retinal prosthesis technology are also outlined, emphasizing progress in engineering and the outlook of retinal prostheses. While acknowledging the challenges and complexities of the technology, this article highlights the significant potential of retinal prostheses for vision restoration in individuals with retinal diseases and calls for continued research and development to refine and enhance their performance, ultimately improving patient outcomes and quality of life.

Retinitis Pigmentosa: Novel Therapeutic Targets and Drug Development

Retinitis pigmentosa (RP) is a heterogeneous group of hereditary diseases characterized by progressive degeneration of retinal photoreceptors leading to progressive visual decline. It is the most common type of inherited retinal dystrophy and has a high burden on both patients and society. This condition causes gradual loss of vision, with its typical manifestations including nyctalopia, concentric visual field loss, and ultimately bilateral central vision loss. It is one of the leading causes of visual disability and blindness in people under 60 years old and affects over 1.5 million people worldwide. There is currently no curative treatment for people with RP, and only a small group of patients with confirmed RPE65 mutations are eligible to receive the only gene therapy on the market: voretigene neparvovec. The current therapeutic armamentarium is limited to retinoids, vitamin A supplements, protection from sunlight, visual aids, and medical and surgical interventions to treat ophthalmic comorbidities, which only aim to slow down the progression of the disease. Considering such a limited therapeutic landscape, there is an urgent need for developing new and individualized therapeutic modalities targeting retinal degeneration. Although the heterogeneity of gene mutations involved in RP makes its target treatment development difficult, recent fundamental studies showed promising progress in elucidation of the photoreceptor degeneration mechanism. The discovery of novel molecule therapeutics that can selectively target specific receptors or specific pathways will serve as a solid foundation for advanced drug development. This article is a review of recent progress in novel treatment of RP focusing on preclinical stage fundamental research on molecular targets, which will serve as a starting point for advanced drug development. We will review the alterations in the molecular pathways involved in the development of RP, mainly those regarding endoplasmic reticulum (ER) stress and apoptotic pathways, maintenance of the redox balance, and genomic stability. We will then discuss the therapeutic approaches under development, such as gene and cell therapy, as well as the recent literature identifying novel potential drug targets for RP.

Effective and economical cell therapy for hair regeneration

We reviewed and summarized the latest reports on the characteristics of stem cells and follicular cells that are under development for hair loss treatment. Compared with conventional medicine, cell therapy could be effective in the long term with a single treatment while having mild adverse effects. Adipose-derived stem cells (ASCs) have the advantages of easy access and large isolation amount compared with dermal papilla cells (DPCs) and dermal sheath cup cells (DSCs), and promote hair growth through the paracrine effect. ASCs have a poor potential in hair neogenesis, therefore, methods to enhance trichogenecity of ASCs should be developed. DSCs can be isolated from the peribulbar dermal sheath cup, while having immune tolerance, and hair inductivity. Therefore, DSCs were first developed and finished the phase II clinical trial; however, the hair growth was not satisfactory. Considering that a single injection of DSCs is effective for at least 9 months in the clinical setting, they can be an alternative therapy for hair regeneration. Though DPCs are not yet studied in clinical trials, we should pay attention to DPCs, as hair loss is associated with gradual reduction of DPCs and DP cell numbers fluctuate over the hair cycle. DPCs could make new hair follicles with epidermal cells, and have an immunomodulatory function to enable allogeneic transplantation. In addition, we can expand large quantities of DPCs with hair inductivity using spheroid culture, hypoxia condition, and growth factor supplement. 'Off-the-shelf' DPC therapy could be effective and economical, and therefore promising for hair regeneration.

3D Bioprinting for Pancreas Engineering/Manufacturing

Diabetes is the most common chronic disease in the world, and it brings a heavy burden to people's health. Against this background, diabetic research, including islet functionalization has become a hot topic in medical institutions all over the world. Especially with the rapid development of microencapsulation and three-dimensional (3D) bioprinting technologies, organ engineering and manufacturing have become the main trends for disease modeling and drug screening. Especially the advanced 3D models of pancreatic islets have shown better physiological functions than monolayer cultures, suggesting their potential in elucidating the behaviors of cells under different growth environments. This review mainly summarizes the latest progress of islet capsules and 3D printed pancreatic organs and introduces the activities of islet cells in the constructs with different encapsulation technologies and polymeric materials, as well as the vascularization and blood glucose control capabilities of these constructs after implantation. The challenges and perspectives of the pancreatic organ engineering/manufacturing technologies have also been demonstrated.

Mesenchymal Stromal Cell-Based Therapy for Dry Eye: Current Status and Future Perspectives

Dry eye is one of the most common chronic diseases in ophthalmology. It affects quality of life and has become a public health problem that cannot be ignored. The current treatment methods mainly include artificial tear replacement therapy, anti-inflammatory therapy, and local immunosuppressive therapy. These treatments are mainly limited to improvement of ocular surface discomfort and other symptoms. In recent years, regenerative medicine has developed rapidly, and ophthalmologists are working on new methods to treat dry eye. Mesenchymal stromal cells (MSCs) have anti-inflammatory, tissue repair, and immune regulatory effects, and have become a promising tool for the treatment of dry eye. These effects can also be produced by MSC-derived exosomes (MSC-Exos). As a cell-free therapy, MSC-Exos are hypoimmunogenic, serve more stable entities, and compared with MSCs, reduce the safety risks associated with the injection of live cells. This article reviews current knowledge about MSCs and MSC-Exos, and highlights the latest progress and future prospects of MSC-based therapy in dry eye treatment.

Extracellular Hemoglobin: Modulation of Cellular Functions and Pathophysiological Effects

Hemoglobin is essential for maintaining cellular bioenergetic homeostasis through its ability to bind and transport oxygen to the tissues. Besides its ability to transport oxygen, hemoglobin within erythrocytes plays an important role in cellular signaling and modulation of the inflammatory response either directly by binding gas molecules (NO, CO, and CO2) or indirectly by acting as their source. Once hemoglobin reaches the extracellular environment, it acquires several secondary functions affecting surrounding cells and tissues. By modulating the cell functions, this macromolecule becomes involved in the etiology and pathophysiology of various diseases. The up-to-date results disclose the impact of extracellular hemoglobin on (i) redox status, (ii) inflammatory state of cells, (iii) proliferation and chemotaxis, (iv) mitochondrial dynamic, (v) chemoresistance and (vi) differentiation. This review pays special attention to applied biomedical research and the use of non-vertebrate and vertebrate extracellular hemoglobin as a promising candidate for hemoglobin-based oxygen carriers, as well as cell culture medium additive. Although recent experimental settings have some limitations, they provide additional insight into the modulatory activity of extracellular hemoglobin in various cellular microenvironments, such as stem or tumor cells niches.

Single-cell sequencing unveils key contributions of immune cell populations in cancer-associated adipose wasting

Adipose tissue loss seen with cancer-associated cachexia (CAC) may functionally drive cachexia development. Using single-cell transcriptomics, we unveil a large-scale comprehensive cellular census of the stromal vascular fraction of white adipose tissues from patients with or without CAC. We report depot- and disease-specific clusters and developmental trajectories of adipose progenitors and immune cells. In adipose tissues with CAC, clear pro-inflammatory transitions were discovered in adipose progenitors, macrophages and CD8+ T cells, with dramatically remodeled cell interactome among these cells, implicating a synergistic effect in promoting tissue inflammation. Remarkably, activated CD8+ T cells contributed specifically to increased IFNG expression in adipose tissues from cachexia patients, and displayed a significant pro-catabolic effect on adipocytes in vitro; whereas macrophage depletion resulted in significantly rescued adipose catabolism and alleviated cachexia in a CAC animal model. Taken together, these results unveil causative mechanisms underlying the chronical inflammation and adipose wasting in CAC.

Therapeutic Strategies in the Fight against COVID-19: From Bench to Bedside

In December 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in China. This virus rapidly spread worldwide and was declared a global pandemic by the World Health Organization (WHO) in March 2020. High incidence, long incubation period, and diverse clinical signs of the disease posed a huge challenge globally. The efforts of health systems have been focused on repurposing existing drugs or developing innovative therapies to reduce the morbidity and mortality associated with SARS-CoV-2. In addition, most of the large pharmaceutical companies are intensely working on vaccine development to swiftly deliver safe and effective vaccines to prevent further spread of the virus. In this review, we will discuss the latest data on therapeutic strategies undergoing clinical trials. Additionally, we will provide a summary of vaccines currently under development.

Inflammatory priming with IL-1β promotes the immunomodulatory behavior of adipose derived stem cells

Inflammatory processes contribute to osteoarthritis (OA) severity and progression. Mesenchymal stem cells, particularly those derived from adipose tissue (ASCs), are able to sense and control the inflammatory environment. This immunomodulatory potential can be boosted by different priming strategies based on inflammatory stimulation. The aim of the present study is to investigate the transcriptional modulation of a huge panel of genes and functionally verify the predicted immunomodulatory ability of ASCs after interleukin one beta (IL-1β) priming. ASCs were isolated from adipose tissue obtained from three donors and expanded. After stimulation with 1 ng/ml of IL-1β for 48 h, cells were collected for gene array and functional tests. Pooled cells from three donors were used for RNA extraction and gene array analysis. Gene Ontology (GO) enrichment analysis and Gene Set Enrichment Analysis (GSEA) were performed to assess the involvement of the modulated genes after priming in specific biological processes and pathways. Functional co-culture tests of ASCs with T cells and macrophages were performed to assess the ability of primed ASCs to modulate immune cell phenotype. Among the overall genes analyzed in the gene array, about the 18% were up- or down-regulated in ASCs after IL-1β priming. GO enrichment analysis of up- or down-regulated genes in ASCs after IL-1β priming allowed identifying specific pathways involved in the modulation of inflammation and extracellular matrix remodeling. The main processes enriched according to the GSEA are related to the inflammatory response and cell proliferative processes. Functional tests on immune cells showed that primed and non-primed ASCs induced a decrease in the CD3+ T lymphocytes survival rate and an anti-inflammatory macrophage polarization. In conclusion, IL-1β priming represents a tailored strategy to enhance the ability of ASCs to direct macrophages towards an anti-inflammatory phenotype and, consequently, improve the efficacy of ASCs in counteracting the OA inflammatory component.

Small extracellular vesicles derived from PD-L1-modified mesenchymal stem cell promote Tregs differentiation and prolong allograft survival

We aimed to explore whether programmed cell death protein-1 ligand (PD-L1) modification on small extracellular vesicles (sEVs) could promote T regulatory cells (Tregs) differentiation. In this study, it was confirmed that under physiological conditions, PD-L1 expression was minimal in the MSCs and absent in the MSC-sEVs. A vector harboring the PD-L1 gene was constructed and transfected into bone marrow mesenchymal stem cells (BM-MSCs). By extracting the sEVs of these modified BM-MSCs and monitoring the expression of the PD-L1 protein, however, PD-L1 expression was substantially increased in the MSCs and concentrated in the sEVs. Then, the rat naïve CD4 + T cells were cocultured with the sEVs derived from the PD-L1-modified MSCs (sEVs^PD-L1). By flow cytometry, a higher percentage of Tregs and anti-inflammatory downstream cytokines (including IL-2, IFN-γ, TGF-β, IL-10) was detected in the sEVs^PD-L1 group than that in the control group treated by either sEVs in wild type, modified by empty vector, or blank control. Suppressive effect on CD4 + T cell proliferation serves as additional evidence to support the immunoregulation capacity of sEVs^PD-L1. The animal model of vascularized composite allograft further confirmed that PD-L1-modified sEVs induce an immune tolerance, by clinically observation, histopathology, T cell fate and cell product. In conclusion, sEVs^PD-L1 efficiently promotes Treg cell differentiation in vitro and in vivo, which suggests their therapeutic potential in the treatment of allograft rejection.

Non-Cytokine Protein Profile of the Mesenchymal Stem Cell Secretome That Regulates the Androgen Production Pathway

Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in reproductive-aged women, and it typically involves elevated androgen levels. Recently, it has been reported that human bone marrow mesenchymal stem cells (hBM-MSCs) can regulate androgen synthesis pathways. However, the details of the mechanism are still unclear. hBM-MSC-derived secreted factors (the secretome) are promising sources of cell-based therapy as they consist of various types of proteins. It is thus important to know which proteins interact with disease-implicated biomolecules. This work aimed to investigate which secretome components contain the key factor that inhibits testosterone synthesis. In this study, we fractionated hBM-MSC-conditioned media into three fractions based on their molecular weights and found that, of the three fractions, one had the ability to inhibit the androgen-producing genes efficiently. We also analyzed the components of this fraction and established a protein profile of the hBM-MSC secretome, which was shown to inhibit androgen synthesis. Our study describes a set of protein components present in the hBM-MSC secretome that can be used therapeutically to treat PCOS by regulating androgen production for the first time.

Islet Encapsulation: New Developments for the Treatment of Type 1 Diabetes

Islet transplantation is a promising approach for the treatment of type 1 diabetes (T1D). Currently, clinical islet transplantation is limited by allo - and autoimmunity that may cause partial or complete loss of islet function within a short period of time, and long-term immunosuppression is required to prevent rejection. Encapsulation into semipermeable biomaterials provides a strategy that allows nutrients, oxygen and secreted hormones to diffuse through the membrane while blocking immune cells and the like out of the capsule, allowing long-term graft survival and avoiding long-term use of immunosuppression. In recent years, a variety of engineering strategies have been developed to improve the composition and properties of encapsulation materials and to explore the clinical practicality of islet cell transplantation from different sources. In particular, the encapsulation of porcine islet and the co-encapsulation of islet cells with other by-standing cells or active ingredients for promoting long-term functionality, attracted significant research efforts. Hydrogels have been widely used for cell encapsulation as well as other therapeutic applications including tissue engineering, cell carriers or drug delivery. Here, we review the current status of various hydrogel biomaterials, natural and synthetic, with particular focus on islet transplantation applications. Natural hydrophilic polymers include polysaccharides (starch, cellulose, alginic acid, hyaluronic acid, chitosan) and peptides (collagen, poly-L-lysine, poly-L-glutamic acid). Synthetic hydrophilic polymers include alcohol, acrylic acid and their derivatives [poly (acrylic acid), poly (methacrylic acid), poly(acrylamide)]. By understanding the advantages and disadvantages of materials from different sources and types, appropriate materials and encapsuling methods can be designed and selected as needed to improve the efficacy and duration of islet. Islet capsule transplantation is emerging as a promising future treatment for T1D.

Arthroscopic Rotator Cuff Repair Augmentation With Autologous Microfragmented Lipoaspirate Tissue Is Safe and Effectively Improves Short-term Clinical and Functional Results: A Prospective Randomized Controlled Trial With 24-Month Follow-up

BACKGROUND

Autologous microfragmented lipoaspirate tissue has been recently introduced in orthopaedics as an easily available source of nonexpanded adipose-derived mesenchymal stem cells. Autologous microfragmented lipoaspirate tissue is expected to create a suitable microenvironment for tendon repair and regeneration. Rotator cuff tears show a high incidence of rerupture and represent an ideal target for nonexpanded mesenchymal stem cells.

PURPOSE

To evaluate the safety and efficacy of autologous lipoaspirate tissue in arthroscopic rotator cuff repair.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Consecutive patients referring to the investigation center for surgical treatment of magnetic resonance imaging-confirmed degenerative posterosuperior rotator cuff tears were assessed for eligibility. Those who were included were randomized to receive a single-row arthroscopic rotator cuff repair, followed by intraoperative injection of autologous microfragmented adipose tissue processed with an enzyme-free technology (treatment group) or not (control group). Clinical follow-up was conducted at 3, 6, 12, 18, and 24 months; at 18 months after surgery, magnetic resonance imaging of the operated shoulder was obtained to assess tendon integrity and rerupture rate.

RESULTS

An overall 177 patients were screened, and 44 (22 per group) completed the 24-month follow-up. A statistically significant difference in favor of the treatment group in terms of Constant-Murley score emerged at the primary endpoint at 6-month follow-up (mean ± SD; control group, 76.66 ± 10.77 points; treatment group, 82.78 ± 7.00 points; P = .0050). No significant differences in clinical outcome measures were encountered at any of the other follow-up points. No significant differences emerged between the groups in terms of rerupture rate, complication rate, and number of adverse events.

CONCLUSION

This prospective randomized controlled trial demonstrated that the intraoperative injection of autologous microfragmented adipose tissue is safe and effective in improving short-term clinical and functional results after single-row arthroscopic rotator cuff repair.

REGISTRATION

NCT02783352 (ClinicalTrials.gov identifier).

Differentiation of multipotent stem cells to insulin-producing cells for treatment of diabetes mellitus: bone marrow- and adipose tissue-derived cells comparison

BACKGROUND

Mesenchymal stem cells (MSCs) from human adipose tissue and bone marrow have a great potential for use in cell therapy due to their ease of isolation, expansion, and differentiation. Our intention was to isolate and promote in vitro expansion and differentiation of MSCs from human adipose and bone marrow tissue into cells with a pancreatic endocrine phenotype and to compare the potency of these cells together.

METHODS AND RESULTS

MSCs were pre-induced with nicotinamide, mercaptoethanol, B-27 and b-FGF in L-DMEM for 2 days and re-induced again in supplemented H-DMEM for another 3 days. Expression of five genes in differentiated beta cells was evaluated by Real-time PCR and western blotting and the potency of insulin release in response to glucose stimulation was evaluated by insulin and C-peptide ELISA kit. The differentiated cells were evaluated by immunocytochemistry staining for Insulin and PDX-1. Quantitative RT-PCR results showed up-regulation of four genes in differentiated beta-islet cells (Insulin, Ngn-3, Pax-4 and Pdx-1) compared with the control. Western blot analysis showed that MSCs cells mainly produced proinsulin and insulin after differentiation but nestin was more expressed in pre-differentiated stem cells. Glucose and insulin secretion assay showed that insulin levels and C-peptide secretion were significantly increased in response to 10 mM glucose.

CONCLUSIONS

Our study showed that both adipose and bone marrow stem cells could differentiate into functional beta-islet cells but it seems that adipose stem cells could be a better choice for treatment of diabetes mellitus according to their higher potency.

The use of patient-specific stem cells in different autoimmune diseases

Autoimmune diseases are developed when the immune system mistakenly attacks the body’s cells. These inflammatory disorders can be inherited or triggered by external forces, such as type 1 diabetes, which is caused by the immune system's destruction of pancreatic beta cells. So far, stem cells such as hESC and iPSC have been used to treat autoimmune disorders such as type 1 diabetes, rheumatoid arthritis (RA), multiple sclerosis (MS), and systemic lupus erythematosus (SLE), although these procedures have certain ethical concerns. On the other hand, bone marrow-derived mesenchymal stem cells (BM-MSC) are thought to be the best source of stem cells. Later, it was shown that mesenchymal stem cells produced from autologous adipose tissues have a great potential for producing huge volumes of stem cells. In-vitro and in-vivo investigations using autologous hematopoietic stem cells and autologous mesenchymal stem cells have been carried out on various rodent and human models, while clinical trials for inflammatory diseases such as multiple sclerosis and diabetes mellitus have yielded promising results. We attempted to summarise the usage of diverse stem cells in the therapy of various autoimmune disorders in this review. Shortly, we expect that the use of autologous stem cells will provide a new perspective on the treatment of autoimmune disorders.

The immunomodulatory potential of murine adipose-derived mesenchymal stem cells is enhanced following culture on chitosan film

INTRODUCTION

Recent studies show that the paracrine immunomodulatory effects of mesenchymal stem cells (MSCs) are mediated by the secretion of interleukin-10 (IL-10), transforming growth factor-beta (TGF β), and nitric oxide (NO). The preconditioning of MSCs improves their immunomodulatory characteristics. Chitosan is a biopolymer with low toxicity and biodegradability, used as a membrane for MSCs three-dimensional culture. The present study aimed to evaluate the levels of immunomodulatory mediators of mesenchymal cells cultured on the chitosan film.

MATERIALS & METHODS

MSCs were isolated from abdominal adipose tissue of BALB/c mice. Flow cytometry and differential culture medium were used to confirm the identity of isolated mesenchymal stem cells. The MSCs were divided into three groups; The first group was treated with 10 ng/mL LPS. The second group was seeded in the flasks coated with the chitosan film (3% w/v). The last group was cultured in the flasks without any preconditioning. After 72 h, IL-10, TGF-β, and NO concentrations were measured in the conditioned media. In addition, the arginase activity in mesenchymal stem cells was measured using a colorimetric method.

RESULTS

The proliferative spindle-shaped MSCs formed several three-dimensional spheroids on the chitosan film. It was shown that the level of TGF-β and IL-10 were increased significantly after treatment with LPS (P = 0.02) and spheroid formation (P = 0.01). In addition, the arginase activity was enormously augmented in spheroids compared to controls (7.13-fold increase; 1.71 ± 0.08 and 0.24 ± 0.01 respectively; P = 0.021). On the other hand, the LPS treatment but not the culture on chitosan film increased the NO level significantly (P = 0.02 and P = 0.14, respectively).

CONCLUSION

Using chitosan film as a three-dimensional culture strategy significantly affects the production of immunosuppressive factors by MSCs in vitro through increased secretion of TGF-β and IL-10 and arginase activity.

The Clinical Trials of Mesenchymal Stromal Cells Therapy

Mesenchymal stromal cells (MSCs) are a heterogeneous population of adult stem cells, which are multipotent and possess the ability to differentiate/transdifferentiate into mesodermal and nonmesodermal cell lineages. MSCs display broad immunomodulatory properties since they are capable of secreting growth factors and chemotactic cytokines. Safety, accessibility, and isolation from patients without ethical concern make MSCs valuable sources for cell therapy approaches in autoimmune, inflammatory, and degenerative diseases. Many studies have been conducted on the application of MSCs as a new therapy, but it seems that a low percentage of them is related to clinical trials, especially completed clinical trials. Considering the importance of clinical trials to develop this type of therapy as a new treatment, the current paper is aimed at describing characteristics of MSCs and reviewing relevant clinical studies registered on the NIH database during 2016-2020 to discuss recent advances on MSC-based therapeutic approaches being used in different diseases.

Amniotic stromal stem cell-loaded hydrogel repairs cardiac tissue in infarcted rat hearts via paracrine mediators

The use of stem cells to repair the heart after a myocardial infarction (MI) remains promising, yet clinical trials over the past 20 years suggest that cells fail to integrate into the native tissue, resulting in limited improvements in cardiac function. Here, we demonstrate the cardioprotective potential of a composite inserting human amniotic stromal mesenchymal stem cells (ASMCs) in a chitosan and hyaluronic acid (C/HA) based hydrogel in a rat MI model. Mechanical characterization of the C/HA platform indicated a swift elastic conversion at 40°C and a rapid sol-gel transition time at 37°C. Cell viability assay presented active and proliferating AMSCs in the C/HA. The ASMCs + C/HA injected composite significantly increased left ventricular ejection fraction, fractional shortening, and neovessel formation. The encapsulated AMSCs were abundantly detected in the infarcted myocardium 6 weeks post-administration and co-expressed cardiac proteins and notably proliferative markers. Proteomic profiling revealed that extracellular vesicles released from hypoxia preconditioned ASMCs contained proteins involved in cytoprotection, angiogenesis, cardiac differentiation and non-canonical Wnt-signaling. Independent activation of non-canonical Wnt-signaling pathways in ASMCs induced cardiogenesis. Despite a low injected cellular density at baseline, the encapsulated AMSCs were abundantly retained and increased cardiac function. Furthermore, the C/HA hydrogel provided an active milieu for the AMSCs to proliferate, co-express cardiac proteins, and induce new vessel formation. Hence, this novel composite of AMSCs + C/HA scaffold is a conceivable candidate that could restore cardiac function and reduce remodeling.

Human Wharton's Jelly-Derived Mesenchymal Stromal Cells Primed by Tumor Necrosis Factor-α and Interferon-γ Modulate the Innate and Adaptive Immune Cells of Type 1 Diabetic Patients

The unique immunomodulation and immunosuppressive potential of Wharton’s jelly-derived mesenchymal stromal cells (WJ-MSCs) make them a promising therapeutic approach for autoimmune diseases including type 1 diabetes (T1D). The immunomodulatory effect of MSCs is exerted either by cell-cell contact or by secretome secretion. Cell-cell contact is a critical mechanism by which MSCs regulate immune-responses and generate immune regulatory cells such as tolerogenic dendritic cells (tolDCs) and regulatory T cell (Tregs). In this study, we primed WJ-MSCs with TNF-α and IFN-γ and investigated the immunomodulatory properties of primed WJ-MSCs on mature dendritic cells (mDCs) and activated T cells differentiated from mononuclear cells (MNCs) of T1D patient’s. Our findings revealed that primed WJ-MSCs impaired the antigen-mediated immunity, upregulated immune-tolerance genes and downregulated immune-response genes. We also found an increase in the production of anti-inflammatory cytokines and suppression of the production of pro-inflammatory cytokines. Significant upregulation of FOXP3, IL10 and TGFB1 augmented an immunosuppressive effect on adaptive T cell immunity which represented a strong evidence in support of the formation of Tregs. Furthermore, upregulation of many critical genes involved in the immune-tolerance mechanism (IDO1 and PTGES2/PTGS) was detected. Interestingly, upregulation of ENTPD1/NT5E genes express a strong evidence to switch immunostimulatory response toward immunoregulatory response. We conclude that WJ-MSCs primed by TNF-α and IFN-γ may represent a promising tool to treat the autoimmune disorders and can provide a new evidence to consider MSCs- based therapeutic approach for the treatment of TID.

Human Wharton's jelly-derived mesenchymal stem cells alleviate concanavalin A-induced fulminant hepatitis by repressing NF-κB signaling and glycolysis

Background

Fulminant hepatitis is a severe life-threatening clinical condition with rapid progressive loss of liver function. It is characterized by massive activation and infiltration of immune cells into the liver and disturbance of inflammatory cytokine production. Mesenchymal stem cells (MSCs) showed potent immunomodulatory properties. Transplantation of MSCs is suggested as a promising therapeutic approach for a host of inflammatory conditions.

Methods

In the current study, a well-established concanavalin A (Con A)-induced fulminant hepatitis mouse model was used to investigate the effects of transplanting human umbilical cord Wharton's jelly-derived MSCs (hWJ-MSCs) on fulminant hepatitis.

Results

We showed that hWJ-MSCs effectively alleviate fulminant hepatitis in mouse models, primarily through inhibiting T cell immunity. RNA sequencing of liver tissues and human T cells co-cultured with hWJ-MSCs showed that NF-κB signaling and glycolysis are two main pathways mediating the protective role of hWJ-MSCs on both Con A-induced hepatitis in vivo and T cell activation in vitro.

Conclusion

In summary, our data confirmed the potent therapeutic role of MSCs-derived from Wharton's jelly of human umbilical cord on Con A-induced fulminant hepatitis, and uncovered new mechanisms that glycolysis metabolic shift mediates suppression of T cell immunity by hWJ-MSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02560-x.

Function of Dental Follicle Progenitor/Stem Cells and Their Potential in Regenerative Medicine: From Mechanisms to Applications

Dental follicle progenitor/stem cells (DFPCs) are a group of dental mesenchyme stem cells that lie in the dental follicle and play a critical role in tooth development and maintaining function. Originating from neural crest, DFPCs harbor a multipotential differentiation capacity. More importantly, they have superiorities, including the easy accessibility and abundant sources, active self-renewal ability and noncontroversial sources compared with other stem cells, making them an attractive candidate in the field of tissue engineering. Recent advances highlight the excellent properties of DFPCs in regeneration of orofacial tissues, including alveolar bone repair, periodontium regeneration and bio-root complex formation. Furthermore, they play a unique role in maintaining a favorable microenvironment for stem cells, immunomodulation and nervous related tissue regeneration. This review is intended to summarize the current knowledge of DFPCs, including their stem cell properties, physiological functions and clinical application potential. A deep understanding of DFPCs can thus inspire novel perspectives in regenerative medicine in the future.

Mesenchymal stem cell therapy ameliorates metabolic dysfunction and restores fertility in a PCOS mouse model through interleukin-10

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder in reproductive-age women. Excessive inflammation and elevated androgen production from ovarian theca cells are key features of PCOS. Human bone marrow mesenchymal stem cells (BM-hMSC) and their secreted factors (secretome) exhibit robust anti-inflammatory capabilities in various biological systems. We evaluated the therapeutic efficacy of BM-hMSC and its secretome in both in vitro and in vivo PCOS models.

METHODS

For in vitro experiment, we treated conditioned media from BM-hMSC to androgen-producing H293R cells and analyzed androgen-producing gene expression. For in vivo experiment, BM-hMSC were implanted into letrozole (LTZ)-induced PCOS mouse model. BM-hMSC effect in androgen-producing cells or PCOS model mice was assessed by monitoring cell proliferation (immunohistochemistry), steroidogenic gene expression (quantitative real-time polymerase chain reaction [qRT-PCR] and Western blot, animal tissue assay (H&E staining), and fertility by pup delivery.

RESULTS

BM-hMSC significantly downregulate steroidogenic gene expression, curb inflammation, and restore fertility in treated PCOS animals. The anti-inflammatory cytokine interleukin-10 (IL-10) played a key role in mediating the effects of BM-hMSC in our PCOS models. We demonstrated that BM-hMSC treatment was improved in metabolic and reproductive markers in our PCOS model and able to restore fertility.

CONCLUSION

Our study demonstrates for the first time the efficacy of intra-ovarian injection of BM-hMSC or its secretome to treat PCOS-related phenotypes, including both metabolic and reproductive dysfunction. This approach may represent a novel therapeutic option for women with PCOS. Our results suggest that BM-hMSC can reverse PCOS-induced inflammation through IL-10 secretion. BM-hMSC might be a novel and robust therapeutic approach for PCOS treatment.

IL-1β pre-stimulation enhances the therapeutic effects of endometrial regenerative cells on experimental colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic, relapsing, and non-specific inflammatory bowel disease, and the current treatment strategies were mainly used to relieve symptoms or for maintenance. Endometrial regenerative cells (ERCs) are mesenchymal-like stromal cells and have been demonstrated to alleviate multiple immune-dysregulation diseases. Pro-inflammatory stimuli were reported to enhance the immunosuppressive functions of ERCs, but the mechanism underlined is not fully understood. Here, we have designed this study to investigate the therapeutic effects of IL-1β-primed ERCs in the attenuation of experimental colitis.

METHODS

BALB/c mice were given 3% dextran sodium sulfate (DSS) for 7 consecutive days and free tap water for 3 days sequentially to induce experimental colitis. PBS (200 μL), ERCs, and IL-1β-primed ERCs (10ng/mL, 48 h) were injected (1 million/mouse/day, i.v.) on day 2, 5, and 8, respectively. Colonic and splenic samples were harvested on day 10 after DSS induction.

RESULTS

It was found that IL-1β-primed ERC treatment markedly attenuated colonic damage, body weight loss, and colon length shortening in colitis mice. Compared with other treatments, cell populations of CD4⁺IL-4⁺Th2 cells, CD4⁺CD25⁺FOXP3⁺ regulatory T cells (Tregs), and CD68⁺CD206⁺ macrophages in spleens were also significantly upregulated in the IL-1β-primed ERC-treated group (p < 0.05). In addition, lower expression of pro-inflammatory (IFN-γ, IL-17, TNF-α, and IL-6), but higher levels of anti-inflammatory cytokines (IL-4 and IL-10) were detected in colons in the IL-1β-primed ERC-treated group (p < 0.05 vs. other groups). Importantly, we also found that different generations of ERCs had an overall lower secretion of Dickkopf-1 (DKK1) by IL-1β pre-stimulation (p < 0.05) and a higher expression of β-catenin in colonic and splenic tissues after the administration of IL-1β-primed ERCs.

CONCLUSIONS

This study has demonstrated that IL-1β pre-stimulation effectively downregulated DKK1 expression in ERCs, which in turn promoted the wnt/β-catenin pathway activation in colonic and splenic tissues. Consequently, IL-1β-primed ERCs exhibited an enhanced therapeutic effect in the attenuation of DSS-induced colitis.

Recent Trends in Multipotent Human Mesenchymal Stem/Stromal Cells: Learning from History and Advancing Clinical Applications

Early cell biology reports demonstrated the presence of cells with stem-like properties in bone marrow, with both hematopoietic and mesenchymal lineages. Over the years, various investigations have purified and characterized mesenchymal stromal/stem cells (MSCs) from different human tissues as cells with multilineage differentiation potential under the appropriate conditions. Due to their appealing characteristics and versatile potentials, MSCs are leveraged in many applications in medicine such as oncology, bioprinting, and as recent as therapeutics discovery and innovation for COVID-19. To date, studies indicate that MSCs have varied differentiation capabilities into different cell types, and demonstrate immunomodulating and anti-inflammatory properties. Different microenvironments or niche for MSCs and their resulting heterogeneity may influence attendant cellular behavior and differentiation capacity. The potential clinical applications of MSCs and exosomes derived from these cells have led to an avalanche of research reports on their properties and hundreds of clinical trials being undertaken. There is ample reason to think, as discussed in this expert review that the future looks bright and promising for MSC research, with many clinical trials under way to ascertain their clinical utility. This review provides a synthesis of the latest advances and trends in MSC research to allow for broad and critically informed use of MSCs. Early observations of the presence of these cells in the bone marrow and their remarkable differentiation capabilities and immunomodulation are also presented.

Regenerative Medicine in COVID-19 Treatment: Real Opportunities and Range of Promises

Novel coronavirus disease (COVID-19) has attracted much attention around the world due to its rapid transmission among humans and relatively high mortality rate. Studies are increasing to find the best therapeutic approach for the disease and its management. Regenerative medicine offers various cell-tissue therapeutics and related products, such as stem cell therapy, natural killer (NK) cell therapy, Chimeric antigen receptor (CAR) T cell therapy, exosomes, and tissue products. Interestingly, mesenchymal stem cells (MSCs) can reduce inflammatory symptoms and protect against cytokine storm, which critically contributes to the COVID-19 progression. Notably, having the potentials to exert cytotoxic effects on infected cells and induce interferon production probably make NK cells a candidate for COVID-19 cell therapy. Besides, exosomes are one of the crucial products of cells that can exert therapeutic effects through the induction of immune responses and neutralizing antibody titers. The paper aims to briefly consider current options for COVID-19 therapy to show that there is no specific cure for COVID-19, and then assess the real opportunities and range of promises regenerative medicine can provide for specific treatment of COVID-19. Graphical Abstract Therapeutic Potential of Regenerative Medicine against COVID19.

Enhancing TNBC Chemo-immunotherapy via combination reprogramming tumor immune microenvironment with Immunogenic Cell Death

Tumor-associated fibroblasts (TAFs) play an important role in tumor progression and therapeutic response, especially in the immunosuppressive tumor microenvironment (TME). To remodel immunosuppressive TME of 4T1 tumor, we developed a nano liposome to deliver silybin (SLN, an anti-liver fibrosis Chinese Traditional Medicine). Liposomal silybin (SLN/LIP) possessed a spherical shape with particle sizes of 75.2 nm, high stability, and good accumulation in the tumor site. After treated with SLN/LIP, α-SMA positive TAFs and the deposition of stroma were decreased significantly. SLN/LIP also changed the tumor immune microenvironment through the increase of IFN-γ and IL-12, as well as reduced of TGF-β, SDF-1, IL6 and TNF-α. Importantly, SLN/LIP enhanced the infiltration of cytotoxic T cells (CTLs) and transformed a "cold" tumor into a "hot" tumor. To achieve the higher antitumor efficacy, an immunogenic cell death (ICD) inducer, liposomal doxorubicin (DOX/LIP) was combined with SLN/LIP. The combination treatment led to trigger immunogenic tumor apoptosis, and enhance antitumor immunity, therefore, improved anti-tumor efficiency, and further prolonged survival duration. The combination of liposomal silybin and liposomal doxorubicin might be a new chemo-immunotherapy approach for triple negative breast cancer (TNBC) tumor treatment.

Hepatocyte growth factor mediates a novel form of hepatic stem/progenitor cell-induced tolerance in a rat xenogeneic liver rejection model

We have previously identified novel neural/glial antigen 2-expressing hepatic stem/progenitor cells (NG2+ HSPs) that are beneficial for tissue repair by inhibiting the immune cell response. In this in vivo study, we investigated the use of hepatocyte growth factor (HGF)-secreting NG2+ HSPs as a tolerogen in the well-established Syrian golden hamster (SGH) to Lewis (LEW) xenogeneic rat acute liver rejection (ARJ) model. Liver and blood cells were collected for histology and functional analyses using immunofluorescence staining, western blot, ELISA, and TUNEL assays. All recipient rats were randomly divided into 5 groups (n = 14 rats/group) and treated with: (1) ARJ + PBS: (2) ARJ + NG2: tail vein injection of NG2+ HSPs; (3) ARJ + tacrolimus (FK506, oral administration); (4) ARJ + an anti-cMet functional blocking antibody (a-cMet-Ab, I.V) 24 h before the injection of NG2+ HSPs; (5) ARJ + cHGF (clinically used HGF). LEW to LEW syngeneic rats were considered "normal" (n = 14, namely Syn). Significantly prolonged mean survival times (MSTs) and improved graft functions were observed after NG2+ HSP transplantation. An anti-cMet Ab significantly blocked the effect of NG2+ HSPs, suggesting that the effects were likely associated with HGF secreted from NG2+ HSPs. Notably, when intravenously injected into the xenogeneic rat model, the injected cHGF not only prolonged the MST of recipient rats but also increased the number of TUNEL-expressing xenoreactive cytotoxic T lymphocytes (CD8+ T cells). Based on these results, HGF-secreting NG2+ HSPs may specifically target recipient CD8+ T cells by inducing their apoptosis.

Toward a Consensus View of Mammalian Adipocyte Stem and Progenitor Cell Heterogeneity

White adipose tissue (WAT) is a cellularly heterogeneous endocrine organ that not only serves as an energy reservoir, but also actively participates in metabolic homeostasis. Among the main constituents of adipose tissue are adipocytes, which arise from adipose stem and progenitor cells (ASPCs). While it is well known that these ASPCs reside in the stromal vascular fraction (SVF) of adipose tissue, their molecular heterogeneity and functional diversity is still poorly understood. Driven by the resolving power of single-cell transcriptomics, several recent studies provided new insights into the cellular complexity of ASPCs among different mammalian fat depots. In this review, we present current knowledge on ASPCs, their population structure, hierarchy, fat depot-specific nature, function, and regulatory mechanisms, and discuss not only the similarities, but also the differences between mouse and human ASPC biology.

Potential of Extracellular Vesicle-Associated TSG-6 from Adipose Mesenchymal Stromal Cells in Traumatic Brain Injury

Multipotent mesenchymal stromal cells (MSC) represent a promising strategy for a variety of medical applications. Although only a limited number of MSC engraft and survive after in vivo cellular infusion, MSC have shown beneficial effects on immunomodulation and tissue repair. This indicates that the contribution of MSC exists in paracrine signaling, rather than a cell-contact effect of MSC. In this review, we focus on current knowledge about tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) and mechanisms based on extracellular vesicles (EV) that govern long-lasting immunosuppressive and regenerative activity of MSC. In this context, in particular, we discuss the very robust set of findings by Jha and colleagues, and the opportunity to potentially extend their research focus on EV isolated in concentrated conditioned media (CCM) from adipose tissue derived MSC (ASC). Particularly, the authors showed that ASC-CCM mitigated visual deficits after mild traumatic brain injury in mice. TSG-6 knockdown ASC were, then, used to generate TSG-6-depleted CCM that were not able to replicate the alleviation of abnormalities in injured animals. In light of the presented results, we envision that the infusion of much distilled ASC-CCM could enhance the alleviation of visual abnormalities. In terms of EV research, the advantages of using size-exclusion chromatography are also highlighted because of the enrichment of purer and well-defined EV preparations. Taken together, this could further delineate and boost the benefit of using MSC-based regenerative therapies in the context of forthcoming clinical research testing in diseases that disrupt immune system homeostasis.

Effect of Nanostructured Scaffold on Human Adipose-Derived Stem Cells: Outcome of In Vitro Experiments

This work is addressed to provide, by in vitro experiments, results on the repercussion that a nanostructured scaffold could have on viability, differentiation and secretion of bioactive factors of human adipose-derived stem cells (hASCs) when used in association to promote angiogenesis, a crucial condition to favour tissue regeneration. To achieve this aim, we evaluated cell viability and morphology by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay and microscopy analysis, respectively. We also investigated the expression of some of those genes involved in angiogenesis and differentiation processes utilizing quantitative polymerase chain reaction (qPCR), whereas the amounts of Vascular Endothelial Growth Factor A, Interleukin 6 and Fatty Acid-Binding Protein 4 secreted in the culture medium, were quantified by enzyme-linked immunosorbent assay (ELISA). Results suggested that, in the presence of the scaffold, cell proliferation and the exocytosis of factors involved in the angiogenesis process are reduced; by contrast, the expression of those genes involved in hASC differentiation appeared enhanced. To guarantee cell survival, the construct dimensions are, generally, smaller than clinically required. Furthermore, being the paracrine event the primary mechanism exerting the beneficial effects on injured tissues, the use of conditioned culture medium instead of cells may be convenient.

Encapsulation of Adipose-Derived Mesenchymal Stem Cells in Calcium Alginate Maintains Clonogenicity and Enhances their Secretory Profile

Adipose-derived mesenchymal stem cells (ASCs) are well known for their secretory potential, which confers them useful properties in cell therapy. Nevertheless, this therapeutic potential is reduced after transplantation due to their short survival in the human body and their migration property. This study proposes a method to protect cells during and after injection by encapsulation in microparticles of calcium alginate. Besides, the consequences of encapsulation on ASC proliferation, pluripotential, and secretome were studied. Spherical particles with a mean diameter of 500 µm could be obtained in a reproducible manner with a viability of 70% after 16 days in vitro. Moreover, encapsulation did not alter the proliferative properties of ASCs upon return to culture nor their differentiation potential in adipocytes, chondrocytes, and osteocytes. Concerning their secretome, encapsulated ASCs consistently produced greater amounts of interleukin-6 (IL-6), interleukin-8 (IL-8), and vascular endothelial growth factor (VEGF) compared to monolayer cultures. Encapsulation therefore appears to enrich the secretome with transforming growth factor β1 (TGF-β1) and macrophage inflammatory protein-1β (MIP-1β) not detectable in monolayer cultures. Alginate microparticles seem sufficiently porous to allow diffusion of the cytokines of interest. With all these cytokines playing an important role in wound healing, it appears relevant to investigate the impact of using encapsulated ASCs on the wound healing process.

Allogeneic umbilical cord-derived mesenchymal stem cells for treating critical-sized bone defects: a translational study

INTRODUCTION

The current 'gold-standard' treatment of critical-sized bone defects (CSBDs) is autografts; however, they have drawbacks including lack of massive bone source donor site morbidity, incomplete remodeling, and the risk of infection. One potential treatment for treating CSBDs is bone marrow-derived mesenchymal stem cells (BM-MSCs). Previously, there were no studies regarding the use of human umbilical cord-mesenchymal stem cells (hUC-MSCs) for treating BDs. We aim to investigate the use of allogeneic hUC-MSCs for treating CSBDs.

METHOD

We included subjects who were diagnosed with non-union fracture with CSBDs who agreed to undergo hUC-MSCs implantation. All patients were given allogeneic hUC-MSCs. All MSCs were obtained and cultured using the multiple-harvest explant method. Subjects were evaluated functionally using the Lower Extremity Functional Scale (LEFS) and radiologically by volume defect reduction.

RESULT

A total of seven (3 male, 4 female) subjects were recruited for this study. The subjects age ranged from 14 to 62 years. All seven subjects had increased LEFS during the end of the follow-up period, indicating improved functional ability. The follow-up period ranged from 12 to 36 months. One subject had wound dehiscence and infection, and two subjects developed partial union.

CONCLUSION

Umbilical cord mesenchymal stem cells are a potential new treatment for CSBDs. Additional studies with larger samples and control groups are required to further investigate the safety and efficacy of umbilical cord-derived mesenchymal stem cells for treating CSBDs.

Lentivirus-mediated IL-10-expressing Bone Marrow Mesenchymal Stem Cells promote corneal allograft survival via upregulating lncRNA 003946 in a rat model of corneal allograft rejection

Rationale: Corneal transplantation is an effective treatment to corneal blindness. However, the immune rejection imperils corneal allograft survival. An interventional modality is urgently needed to inhibit immune rejection and promote allograft survival. In our previous study, subconjunctival injections of bone marrow-derived mesenchymal stem cells (BM-MSCs) into a rat model of corneal allograft rejection extended allograft survival for 2 d. In this study, we sought to generate IL-10-overexpressing BM-MSCs, aiming to boost the survival-promoting effects of BM-MSCs on corneal allografts and explore the molecular and cellular mechanisms underlying augmented protection. Methods: A population of IL-10-overexpressing BM-MSCs (designated as IL-10-BM-MSCs) were generated by lentivirus transduction and FACS purification. The self-renewal, multi-differentiation, and immunoinhibitory capabilities of IL-10-BM-MSCs were examined by conventional assays. The IL-10-BM-MSCs were subconjunctivally injected into the model of corneal allograft rejection, and the allografts were monitored on a daily basis. The expression profiling of long noncoding RNA (lncRNA) in the allografts was revealed by RNA sequencing and verified by quantitative real-time PCR. The infiltrating immune cell type predominantly upregulating the lncRNA expression was identified by RNAscope in situ hybridization. The function of the upregulated lncRNA was proved by loss- and gain-of-function experiments both in vivo and in vitro. Results: The IL-10-BM-MSCs possessed an enhanced immunoinhibitory capability and unabated self-renewal and multi-differentiation potentials as compared to plain BM-MSCs. The subconjunctivally injected IL-10-BM-MSCs reduced immune cell infiltration and doubled allograft survival time (20 d) as compared to IL-10 protein or plain BM-MSCs in the corneal allograft rejection model. Further, IL-10-BM-MSCs significantly upregulated lncRNA 003946 expression in CD68⁺ macrophages infiltrating corneal allografts. Silencing and overexpressing lncRNA 003946 in macrophage cultures abolished and mimicked the IL-10-BM-MSCs' suppressing effects on the macrophages' antigen presentation, respectively. In parallel, knocking down and overexpressing the lncRNA in vivo abrogated and simulated the survival-promoting effects of IL-10-BM-MSCs on corneal allografts, respectively. Conclusion: The remarkable protective effects of IL-10-BM-MSCs support further developing them into an effective interventional modality against corneal allograft rejection. IL-10-BM-MSCs promote corneal allograft survival mainly through upregulating a novel lncRNA expression in graft-infiltrating CD68⁺ macrophages. LncRNA, for the first time, is integrated into an IL-10-BM-MSC-driven immunomodulatory axis against the immune rejection to corneal allograft.

Lung-resident mesenchymal stem cells regulated the inflammatory responses in innate and adaptive immune cells through HVEM-BTLA pathway during ARDS

Acute respiratory distress syndrome (ARDS) is an organ failure syndrome caused by overactivation of the immune system. Mesenchymal stem cells (MSCs) have been found to be effective in ARDS therapy due to their excellent immunomodulatory abilities; however, people are concerned about the safety of infusing exogenous cells. We found that rat lung-resident mesenchymal stem cells (LRMSCs) (Sca-1⁺CD45^-CD31^-) played important roles in regulating inflammation in the lungs during the pathogenesis of ARDS. LRMSCs could regulate the production of cytokines (TNF-α, MCP-1, and IL-10) by both innate and adaptive immune cells following LPS stimulation in vivo or in vitro. We also found that Herpes Virus Entry Mediator (HVEM) expression in LRMSCs enhanced the immunomodulatory ability of LRMSCs, and expression of the HVEM ligand B and T Lymphocyte Attenuator (BTLA) in innate and adaptive immune cells was required. The clarification of this immunoregulatory mechanism may provide evidence for ARDS therapy mediated by mobilizing endogenous MSCs in the future.

Cell Therapy With Mesenchymal Stem Cells Induces an Innate Immune Memory Response That Attenuates Experimental Colitis in the Long Term

BACKGROUND AND AIMS

Mesenchymal stem cells [MSCs] are used in preclinical and clinical studies for treatment of immune-mediated disorders, thanks to their immunomodulatory properties. Cell therapy with MSCs induces multiple effects in the immune system which ultimately lead to increase in the number of immune cells with regulatory phenotype. In this study, we investigated whether the beneficial effects of MSC therapy are maintained in the long term in a clinically relevant mouse model of colitis.

METHODS

A single dose of adipose-derived MSCs [aMSCs] was infused into dextran sulphate sodium [DSS]-induced colitic mice during the induction phase of the disease. Following a latency period of 12 weeks, mice were re-challenged with a second 7-day cycle of DSS.

RESULTS

DSS-induced colitic mice treated with aMSCs showed significant reduction in their colitic disease activity index during the second DSS challenge when compared with non-aMSC treated DSS-induced colitic mice. Strikingly, the long-term protection induced by aMSC therapy was also observed in Rag-1-/- mice where no adaptive immune memory cell responses take place. Increased percentages of Ly6G+CD11b+ myeloid cells were observed 12 weeks after the first inflammatory challenge in the peritoneal cavity, spleen, and bone marrow of DSS-induced colitic mice that were infused with aMSCs. Interestingly, upon re-challenge with DSS, these animals showed a concomitant increase in the regulatory/inflammatory macrophage ratio in the colon lamina propria.

CONCLUSIONS

Our findings demonstrate for the first time that MSC therapy can imprint an innate immune memory-like response in mice which confers sustained protection against acute inflammation in the long term.

Gene-based Therapeutic Tools in the Treatment of Cornea Disease

BACKGROUND

As one of the main blinding ocular diseases, corneal blindness resulted from neovascularization that disrupts the angiogenic privilege of corneal avascularity. Following neovascularization, inflammatory cells are infiltrating into cornea to strengthen corneal injury. How to maintain corneal angiogenic privilege to treat corneal disease has been investigated for decades.

METHODOLOGY

Local administration of viral and non-viral-mediated anti-angiogenic factors reduces angiogenic protein expression in situ with limited or free of off-target effects upon gene delivery. Recently, Mesenchymal Stem Cells (MSCs) have been studied to treat corneal diseases. Once MSCs are manipulated to express certain genes of interest, they could achieve superior therapeutic efficacy after transplantation.

DISCUSSION

In the text, we first introduce the pathological development of corneal disease in the aspects of neovascularization and inflammation. We summarize how MSCs become an ideal candidate in cell therapy for treating injured cornea, focusing on cell biology, property and features. We provide an updated review of gene-based therapies in animals and preclinical studies in the aspects of controlling target gene expression, safety and efficacy. Gene transfer vectors are potent to induce candidate protein expression. Delivered by vectors, MSCs are equipped with certain characters by expressing a protein of interest, which facilitates better for MSC-mediated therapeutic intervention for the treatment of corneal disease.

CONCLUSION

As the core of this review, we discuss how MSCs could be engineered to be vector system to achieve enhanced therapeutic efficiency after injection.

Immunomodulatory Effect of Adipose-Derived Stem Cells: The Cutting Edge of Clinical Application

Adipose-derived stem cells (ASCs) represent a promising tool for soft tissue engineering as well as for clinical treatment of inflammatory and autoimmune pathologies. The well-characterized multi-differentiation potential and self-renewal properties of ASCs are coupled with their immunomodulatory ability in providing therapeutic efficacy. Yet, their impact in immune or inflammatory disorders might rely both on cell contact-dependent mechanisms and paracrine effects, resulting in the release of various soluble factors that regulate immune cells functions. Despite the widespread use of ASCs in clinical trials addressing several pathologies, the pathophysiological mechanisms at the basis of their clinical use have been not yet fully investigated. In particular, a thorough analysis of ASC immunomodulatory potential is mandatory. Here we explore such molecular mechanisms involved in ASC immunomodulatory properties, emphasizing the relevance of the milieu composition. We review the potential clinical use of ASC secretome as a mediator for immunomodulation, with a focus on in vitro and in vivo environmental conditions affecting clinical outcome. We describe some potential strategies for optimization of ASCs immunomodulatory capacity in clinical settings, which act either on adult stem cells gene expression and local microenvironment. Finally, we discuss the limitations of both allogeneic and autologous ASC use, highlighting the issues to be fixed in order to significantly improve the efficacy of ASC-based cell therapy.

TSG-6 in extracellular vesicles from canine mesenchymal stem/stromal is a major factor in relieving DSS-induced colitis

Adipose tissue derived mesenchymal stem/stromal cell (ASC)-derived extracellular vesicles (EV) have been reported to be beneficial against dextran sulfate sodium (DSS)-induced colitis in mice. However, the underlying mechanisms have not been fully elucidated. We hypothesize that the tumor necrosis factor-α-stimulated gene/protein 6 (TSG-6) in EVs is a key factor influencing the alleviation of colitis symptoms. DSS-induced colitis mice (C57BL/6, male, Naïve = 6, Sham = 8, PBS = 8 EV = 8, CTL-EV = 8, TSG-6 depleted EV = 8) were intraperitoneally administered EVs (100 ug/mice) on day 1, 3, and 5; colon tissues were collected on day 10 for histopathological, RT-qPCR, western blot and immunofluorescence analyses. In mice injected with EV, inflammation was alleviated. Indeed, EVs regulated the levels of pro- and anti-inflammatory cytokines, such as TNF-α, IL-1β, IFN-γ, IL-6, and IL-10 in inflamed colons. However, when injected with TSG-6 depleted EV, the degree of inflammatory relief was reduced. Furthermore, TSG-6 in EVs plays a key role in increasing regulatory T cells (Tregs) and polarizing macrophage from M1 to M2 in the colon. In conclusion, this study shows that TSG-6 in EVs is a major factor in the relief of DSS-induced colitis, by increasing the number of Tregs and macrophage polarization from M1 to M2 in the colon.

Mouse Bone Marrow-Derived Mesenchymal Stem Cells Alleviate Perinatal Brain Injury Via a CD8+ T Cell Mechanism in a Model of Intrauterine Inflammation

The objective of this study was to determine if mouse bone marrow-derived mesenchymal stem cells (BMMSCs) ameliorate preterm birth and perinatal brain injury induced by intrauterine inflammation (IUI). A mouse model of IUI-induced perinatal brain injury at embryonic (E) day 17 was utilized. BMMSCs were derived from GFP-transgenic mice and phenotypically confirmed to be CD44⁺, Sca-1⁺, CD45^-, CD34^-, CD11b^-, and CD11c^- by flow cytometry and sorted by fluorescence-activated cell sorting (FACS). Dams were assigned to four groups: phosphate-buffered saline (PBS) + PBS, PBS + BMMSCs, lipopolysaccharide (LPS) + PBS, and LPS + BMMSCs. Following maternal IUI, there was a significant increase in CD8⁺ T cells in the placentas. Maternally administered BMMSCs trafficked to the fetal side of the placenta and resulted in significantly decreased placental CD8⁺ T cells. Furthermore, fetal trafficking of maternally administered BMMSCs correlated with an improved performance on offspring neurobehavioral testing in LPS + BMMSC group compared with LPS + PBS group. Our data support that maternal administration of BMMSCs can alleviate perinatal inflammation-induced brain injury and improve neurobehavioral outcomes in the offspring via CD8⁺ T cell immunomodulation at the feto-placental interface.

The effect of human mesenchymal stem cell injection on pain behavior in chronic post-ischemia pain mice

Background

Neuropathic pain (NP) is considered a clinically incurable condition despite various treatment options due to its diverse causes and complicated disease mechanisms. Since the early 2000s, multipotent human mesenchymal stem cells (hMSCs) have been used in the treatment of NP in animal models. However, the effects of hMSC injections have not been studied in chronic post-ischemia pain (CPIP) mice models. Here, we investigated whether intrathecal (IT) and intrapaw (IP) injections of hMSCs can reduce mechanical allodynia in CPIP model mice.

Methods

Seventeen CPIP C57/BL6 mice were selected and randomized into four groups: IT sham (n = 4), IT stem (n = 5), IP sham (n = 4), and IP stem (n = 4). Mice in the IT sham and IT stem groups received an injection of 5 μL saline and 2 × 10⁴ hMSCs, respectively, while mice in the IP sham and IP stem groups received an injection of 5 μL saline and 2 × 10⁵ hMSCs, respectively. Mechanical allodynia was assessed using von Frey filaments from pre-injection to 30 days post-injection. Glial fibrillary acidic protein (GFAP) expression in the spinal cord and dorsal root ganglia were also evaluated.

Results

IT and IP injections of hMSCs improved mechanical allodynia. GFAP expression was decreased on day 25 post-injection compared with the sham group. Injections of hMSCs improved allodynia and GFAP expression was decreased compared with the sham group.

Conclusions

These results suggested that hMSCs may be also another treatment modality in NP model by ischemia-reperfusion.

Bone Marrow-Derived Mesenchymal Stem Cells Modified with Akt1 Ameliorates Acute Liver GVHD

Background

Liver injury associated with acute graft-versus-host disease (aGVHD) is a frequent and severe complication of hematopoietic stem cell transplantation and remains a major cause of transplant-related mortality. Bone marrow-derived mesenchymal stem cells (BM-MSCs) has been proposed as a potential therapeutic approach for aGVHD. However, the therapeutic effects are not always achieved. In this study, we genetically engineered C57BL/6 mouse BM-MSCs with AKT1 gene and tested whether AKT1-MSCs was superior to control MSCs (Null-MSCs) for cell therapy of liver aGVHD.

Results

In vitro apoptosis analyses showed that, under both routine culture condition and high concentration interferon-γ (IFN-γ) (100ng/mL) stimulation condition, AKT1-MSCs had a survival (anti-apoptotic) advantage compared to Null-MSCs. In vivo imaging showed that AKT1-MSCs had better homing capacity and longer persistence in injured liver compared to Null-MSCs. Most importantly, AKT1-MSCs demonstrated an enhanced immunomodulatory function by releasing more immunosuppressive cytokines, such as IL-10. Adoptive transfer of AKT1-MSCs mitigated the histopathological abnormalities of concanavalin A(ConA)-induced liver injury along with significantly lowered serum levels of ALT and AST. The attenuation of liver injury correlated with the decrease of TNF-α and IFN-γ both in liver tissue and in the serum.

Conclusions

In summary, BM-MSCs genetically modified with AKT1 has a survival advantage and an enhanced immunomodulatory function both in vitro and in vivo and thus demonstrates the therapeutic potential for prevention and amelioration of liver GVHD and other immunity-associated liver injuries.

Investigating the route of administration and efficacy of adipose tissue-derived mesenchymal stem cells and conditioned medium in type 1 diabetic mice

Type 1 diabetes (T1D) is a chronic autoimmune disease destroying the insulin-producing beta cells. Recently, stem cell therapy has been tested to treat T1D. In the present study, we aim to investigate the effects of intraperitoneal and intravenous infusion of multipotent mesenchymal stem/stromal cells (MSCs) and MSC-conditioned medium (MSC-CM) in an experimental model of diabetes, induced by multiple injections of Streptozotocin (STZ). The adipose tissue-derived MSC and MSC-CM were isolated from C57Bl/6 male mice and characterized. Later, MSC and MSC-CM were injected intraperitoneally or intravenously into mice. The blood glucose, urinary glucose, and body weight were measured, and the percentages of CD4+ CD25+ FOXP3+ T cells as well as the levels of IFN-γ, TGF-β, IL-4, IL-17, and IL-10 were evaluated. Our results showed that both intraperitoneal and intravenous infusions of MSC and MSC-CM could decrease the blood glucose, recover pancreatic islets, and increase the levels of insulin-producing cells. Furthermore, the percentage of CD4+ CD25+ FOXP3+ T cells was increased after intraperitoneal injection of MSC or MSC-CM and intravenous injection of MSCs. After intraperitoneal injection of the MSC and MSC-CM, the levels of inflammatory cytokines reduced, while the levels of anti-inflammatory cytokines increased. Together current data showed that although both intraperitoneal and intravenous administration had beneficial effects on T1D animal model, but intraperitoneal injection of AD-MSC and AD-MSC-CM was more effective than systemic administration.