Banking Mesenchymal Stromal Cells from Umbilical Cord Tissue: Large Sample Size Analysis Reveals Consistency Between Donors

Comparative analysis of the effects of different hypoxia mimetic agents on the secretome contents of conditioned medium obtained from mesenchymal stem/stromal cells cultured in 2 or 3-dimensional cell culture systems

Paracrine factors secreted by mesenchymal stem/stromal cells (MSCs) have been demonstrated to have significant therapeutic potential. The secretome profiles of MSCs variate depending on culture conditions. Generally, the effects of a single preconditioning strategy on secretome profiles of MSCs were investigated. However, until now, there has been no study examining the combinatory effects of different preconditioning strategies in a comparative manner. This study aimed to evaluate the secretome contents of conditioned media obtained from human umbilical cord-derived MSCs cultured in 2- or 3-dimensional (D) culture systems preconditioned with deferoxamine (DFS) or dimethyloxalylglycine (DMOG). Immunocytochemical analysis showed that MSCs preconditioned with DFS or DMOG have increased nuclear hypoxia-inducible factor-1α expression. Transmission electron microscopic analysis showed that cells preconditioned with DFS or DMOG have increased autophagic vesicles, which could be attributed to altered energy metabolism under hypoxic conditions. It was revealed that hypoxia-mimetic agents added to the 2D-, or 3D-culture environment raised total protein concentrations per cell along with vascular endothelial growth factor. The concentrations of glial cell-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) were differentially regulated in 2D-, and 3D-culture system, that the secretions of GDNF and NGF per cell were more prominent in 3D- and 2D-culture systems, respectively. These findings indicate that hypoxic conditions alone significantly elevate total protein concentrations, while the contribution of the 3D environment is more modest than initially anticipated. However, concentrations of secreted growth factors may be affected differently depending on the topography of the culture condition and the types of hypoxia mimetic agents.

The therapeutic effects of induced pluripotent stem cell-derived mesenchymal stem cells on Parkinson's disease

Parkinson's disease (PD), characterized by progressive degeneration of dopaminergic neurons in substantia nigra, has no disease-modifying therapy. Mesenchymal stem cell (MSC) therapy has shown great promise as a disease-modifying solution for PD. Induced pluripotent stem cell-derived MSC (iMSC) not only has stronger neural repair function, but also helps solve the problem of MSC heterogeneity. So we evaluated the therapeutic effects of iMSCs on PD. iMSCs were administered by tail vein in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD models of C57BL/6 mice. The results showed iMSCs increased body weights, inhibited the prolongation of latencies to descend in pole tests, the decrease of grip strength in grip strength tests and increase of open arm entries in elevated plus maze test, and showed a trend to alleviate striatal dopamine loss. They indicate iMSCs might improve functions partially by preserving striatal dopamine in PD. We for the first time (1) found that iMSC has therapeutic effects on PD; (2) tested specifically muscle strength in cell therapy for PD and found it increases muscle strength; (3) found cell therapy alleviated the increase of entries into the open arms in PD. It suggests iMSC is a promising candidate for clinical investigations and drug development for PD.

Off-the-Shelf Cord-Blood Mesenchymal Stromal Cells: Production, Quality Control, and Clinical Use

Background Recently, mesenchymal stromal cells (MSCs) have gained recognition for their clinical utility in transplantation to induce tolerance and to improve/replace pharmacological immunosuppression. Cord blood (CB)-derived MSCs are particularly attractive for their immunological naivety and peculiar anti-inflammatory and anti-apoptotic properties.

OBJECTIVES

The objective of this study was to obtain an inventory of CB MSCs able to support large-scale advanced therapy medicinal product (ATMP)-based clinical trials.

STUDY DESIGN

We isolated MSCs by plastic adherence in a GMP-compliant culture system. We established a well-characterized master cell bank and expanded a working cell bank to generate batches of finished MSC(CB) products certified for clinical use. The MSC(CB) produced by our facility was used in approved clinical trials or for therapeutic use, following single-patient authorization as an immune-suppressant agent.

RESULTS

We show the feasibility of a well-defined MSC manufacturing process and describe the main indications for which the MSCs were employed. We delve into a regulatory framework governing advanced therapy medicinal products (ATMPs), emphasizing the need of stringent quality control and safety assessments. From March 2012 to June 2023, 263 of our Good Manufacturing Practice (GMP)-certified MSC(CB) preparations were administered as ATMPs in 40 subjects affected by Graft-vs.-Host Disease, nephrotic syndrome, or bronco-pulmonary dysplasia of the newborn. There was no infusion-related adverse event. No patient experienced any grade toxicity. Encouraging preliminary outcome results were reported. Clinical response was registered in the majority of patients treated under therapeutic use authorization.

CONCLUSIONS

Our 10 years of experience with MSC(CB) described here provides valuable insights into the use of this innovative cell product in immune-mediated diseases.

Perspectives for the Use of Umbilical Cord Blood in Transplantation and Beyond: Initiatives for an Advanced and Sustainable Public Banking Program in Greece

The umbilical cord blood (UCB) donated in public UCB banks is a source of hematopoietic stem cells (HSC) alternative to bone marrow for allogeneic HSC transplantation (HSCT). However, the high rejection rate of the donated units due to the strict acceptance criteria and the wide application of the haploidentical HSCT have resulted in significant limitation of the use of UCB and difficulties in the economic sustainability of the public UCB banks. There is an ongoing effort within the UCB community to optimize the use of UCB in the field of HSCT and a parallel interest in exploring the use of UCB for applications beyond HSCT i.e., in the fields of cell therapy, regenerative medicine and specialized transfusion medicine. In this report, we describe the mode of operation of the three public UCB banks in Greece as an example of an orchestrated effort to develop a viable UCB banking system by (a) prioritizing the enrichment of the national inventory by high-quality UCB units from populations with rare human leukocyte antigens (HLA), and (b) deploying novel sustainable applications of UCB beyond HSCT, through national and international collaborations. The Greek paradigm of the public UCB network may become an example for countries, particularly with high HLA heterogeneity, with public UCB banks facing sustainability difficulties and adds value to the international efforts aiming to sustainably expand the public UCB banking system.

Umbilical cord mesenchymal stromal cells in serum-free defined medium display an improved safety profile

BACKGROUND

Safety evaluations in preclinical studies are needed to confirm before translating a cell-based product into clinical application. We previously developed a serum-free, xeno-free, and chemically defined media (S&XFM-CD) for the derivation of clinical-grade umbilical cord-derived MSCs (UCMSCs), and demonstrated that intraperitoneal administration of UCMSCs in S&XFM-CD (UCMSCS&XFM-CD) exhibited better therapeutic effects than UCMSCs in serum-containing media (SCM, UCMSCSCM). However, a comprehensive investigation of the safety of intraperitoneal UCMSCS&XFM-CD treatment should be performed before clinical applications.

METHODS

In this study, the toxicity, immunogenicity and biodistribution of intraperitoneally transplanted UCMSCS&XFM-CD were compared with UCMSCSCM in rats via general vital signs, blood routine, blood biochemistry, subsets of T cells, serum cytokines, pathology of vital organs, antibody production and the expression of human-specific gene. The tumorigenicity and tumor-promoting effect of UCMSCS&XFM-CD were compared with UCMSCSCM in nude mice.

RESULTS

We confirmed that intraperitoneally transplanted UCMSCS&XFM-CD or UCMSCSCM did not cause significant changes in body weight, temperature, systolic blood pressure, diastolic blood pressure, heart rate, blood routine, T lymphocyte subsets, and serum cytokines, and had no obvious histopathology change on experimental rats. UCMSCS&XFM-CD did not produce antibodies, while UCMSCSCM had very high chance of antibody production to bovine serum albumin (80%) and apolipoprotein B-100 (60%). Furthermore, intraperitoneally injected UCMSCS&XFM-CD were less likely to be blocked by the lungs and migrated more easily to the kidneys and colon tissue than UCMSCSCM. In addition, UCMSCS&XFM-CD or UCMSCSCM showed no obvious tumorigenic activity. Finally, UCMSCS&XFM-CD extended the time of tumor formation of KM12SM cells, and decreased tumor incidence than that of UCMSCSCM.

CONCLUSIONS

Taken together, our data indicate that UCMSCS&XFM-CD display an improved safety performance and are encouraged to use in future clinical trials.

2D and 3D cultured human umbilical cord-derived mesenchymal stem cell-conditioned medium has a dual effect in type 1 diabetes model in rats: immunomodulation and beta-cell regeneration

BACKGROUND

Type 1 diabetes (T1D) is a T-cell-mediated autoimmune disease characterized by the irreversible destruction of insulin-producing β-cells in pancreatic islets. Helper and cytotoxic T-cells and cytokine production, which is impaired by this process, take a synergetic role in β-cell destruction, and hyperglycemia develops due to insulin deficiency in the body. Mesenchymal stem cells (MSCs) appear like an excellent therapeutic tool for autoimmune diseases with pluripotent, regenerative, and immunosuppressive properties. Paracrine factors released from MSCs play a role in immunomodulation by increasing angiogenesis and proliferation and suppressing apoptosis. In this context, the study aims to investigate the therapeutic effects of MSC's secretomes by conditioned medium (CM) obtained from human umbilical cord-derived MSCs cultured in 2-dimensional (2D) and 3-dimensional (3D) environments in the T1D model.

METHODS

First, MSCs were isolated from the human umbilical cord, and the cells were characterized. Then, two different CMs were prepared by culturing MSCs in 2D and 3D environments. The CM contents were analyzed in terms of total protein, IL-4, IL-10, IL-17, and IFN-λ. In vivo studies were performed in Sprague-Dawley-type rats with an autoimmune T1D model, and twelve doses of CM were administered intraperitoneally for 4 weeks within the framework of a particular treatment model. In order to evaluate immunomodulation, the Treg population was determined in lymphocytes isolated from the spleen after sacrification, and IL-4, IL-10, IL-17, and IFN-λ cytokines were analyzed in serum. Finally, β-cell regeneration was evaluated immunohistochemically by labeling Pdx1, Nkx6.1, and insulin markers, which are critical for the formation of β-cells.

RESULTS

Total protein and IL-4 levels were higher in 3D-CM compared to 2D-CM. In vivo results showed that CMs induce the Treg population and regulate cytokine release. When the immunohistochemical results were evaluated together, it was determined that CM application significantly increased the rate of β-cells in the islets. This increase was at the highest level in the 3D-CM applied group.

CONCLUSION

The dual therapeutic effect of MSC-CM on immunomodulation and homeostasis/regeneration of β-cells in the T1D model has been demonstrated. Furthermore, this effect could be improved by using 3D scaffolds for culturing MSCs while preparing CM.

Human Umbilical Cord Mesenchymal Stem Cells-Derived Small Extracellular Vesicles Can Be Considered as Cell-Free Therapeutics for Angiogenesis Promotion

OBJECTIVE

Angiogenesis has critical roles in several physiological processes. Restoring angiogenesis in some pathological conditions such as a few vascular diseases can be a therapeutic approach to controlling this issue. Mesenchymal stem cells (MSCs) secrete specific intracellular products known as extracellular vesicles (EVs) with high therapeutic potential which compared to their source cells, do not have the limitations of cell therapy. The angiogenic effect of the human umbilical cord MSCs (hUCMSCs)-derived small EVs are evaluated in the present work. Aim of this research is to show that hUCMSCs-derived small EVs cause differentiation of genes involved in angiogenesis like FGFR-1, FGF, VEGF, and VEGFR-2.

MATERIALS AND METHODS

In this experimental study, MSCs were isolated from the human umbilical cord, and after confirming their identities, their secreted EVs (including exosomes) were extracted by ultracentrifugation. The isolated small EVs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), bicinchoninic acid assay (BCA), and Western Blotting. Then, the human umbilical vein endothelial cells (HUVECs) were treated with derived small EVs for 72 hours, and the expression of the angiogenic factors including FGFR-1, FGF, VEGF, and VEGFR-2 was evaluated by quantitative real-time-polymerase chain reaction (qPCR). Angiogenesis was also evaluated via a tube formation assay.

RESULTS

The results demonstrated that FGFR-1, FGF, VEGF, and VEGFR-2 could be elevated 2, 2, 3.5, and 2 times, respectively, in EVs treated HUVECs, and derivative EVs can encourage tube formation in HUVECs.

CONCLUSION

These findings imply that hUCMSCs-derived small EVs are valuable resources in promoting angiogenesis and are very promising in cell-free therapy.

Large-Scale Expansion of Human Umbilical Cord-Derived Mesenchymal Stem Cells in a Stirred Suspension Bioreactor Enabled by Computational Fluid Dynamics Modeling

Human umbilical cord-derived mesenchymal stem cells (hUCMSCs) hold great potential to generate novel and curative cell therapy products. However, the current large-scale cultivation of hUCMSCs is based on empirical geometry-dependent methods, limiting the generation of high-quantity and high-quality hUCMSCs for clinical therapy. Herein, we develop a novel scale-up strategy based on computational fluid dynamics (CFD) to effectively expand the hUCMSCs in a 3D tank bioreactor. Using a standardized hUCMSCs line on microcarriers, we successfully translated and expanded the hUCMSCs from a 200 mL spinner flask to a 1.5 L computer-controlled bioreactor by matching the shear environment and suspending the microcarrier. Experimental results revealed that the batch-cultured hUCMSCs in bioreactors with an agitation speed of 40 rpm shared a more favorable growth and physiological state, similar to that run at 45 rpm in a 200 mL spinner flask, showing comparability in both culture systems. Notably, the maximum cell density reached up to 27.3 × 10⁵ cells/mL in fed-batch culture, 2.9 folds of that of batch culture and 20.2 times of seeding cells. As such, efficient process optimization and scale-up expansion of hUCMSCs were achieved in the microcarrier-based bioreactor system by the developed CFD simulation strategy, which provided an alternative toolbox to generate massive and standardized curative cell therapy products.

Human Umbilical Cord Mesenchymal Stem Cell-Based in vitro Model for Neurotoxicity Testing

Neurotoxicity (NT) testing for regulatory purposes is based on in vivo animal testing. There is general consensus, however, about the need for the development of alternative methodologies to allow researchers to more rapidly and cost effectively screen large numbers of chemicals for their potential to cause NT, or to investigate their mode of action. In vitro assays are considered an important source of information for making regulatory decisions, and human cell-based systems are recommended as one of the most relevant models in toxicity testing, to reduce uncertainty in the extrapolation of results from animal-based models. Human neuronal models range from various neuroblastoma cell lines to stem cell-derived systems, including those derived from mesenchymal stem/stromal cells (hMSC). hMSCs exhibit numerous advantages, including the fact that they can be obtained in high yield from healthy human adult tissues, can be cultured with a minimal laboratory setup and without genetic manipulations, are able of continuous and repeated self-renewal, are nontumorigenic, and can form large populations of stably differentiated cells representative of different tissues, including neuronal cells. hMSCs derived from human umbilical cord (hUC) in particular possess several prominent advantages, including a painless, non-invasive, and ethically acceptable collection procedure, simple and convenient preparation, and high proliferation capacity. In addition, hMSCs can be efficiently differentiated into neuron-like cells (hNLCs), which can then be used for the assessment of neuronal toxicity of potential neurotoxic compounds in humans. Here, we describe a step-by-step procedure to use hMSCs from the umbilical cord for in vitro neurotoxicity testing. First, we describe how to isolate, amplify, and store hMSCs derived from the umbilical cord. We then outline the steps to transdifferentiate these cells into hNLCs, and then use the hNLCs for neurotoxicity testing by employing multiple common cytotoxicity assays after treatment with test compounds. The approach follows the most updated guidance on using human cell-based systems. These protocols will allow investigators to implement an alternative system for obtaining primary NLCs of human origin, and support advancement in neurotoxicity research. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Isolation and maintenance of human mesenchymal stem/stromal cells (hMSCs) obtained from the umbilical cord lining membrane Basic Protocol 2: Transdifferentiation of hMSCs into neuron-like cells (hNLCs) and basic neurotoxicity assessment.

OUP accepted manuscript

Bronchopulmonary dysplasia (BPD) is a life-threatening condition in preterm infants with few effective therapies. Mesenchymal stem or stromal cells (MSCs) are a promising therapeutic strategy for BPD. The ideal MSC source for BPD prevention is however unknown. The objective of this study was to compare the regenerative effects of MSC obtained from bone marrow (BM) and umbilical cord tissue (UCT) in an experimental BPD model. In vitro, UCT-MSC demonstrated greater proliferation and expression of anti-inflammatory cytokines as compared to BM-MSC. Lung epithelial cells incubated with UCT-MSC conditioned media (CM) had better-wound healing following scratch injury. UCT-MSC CM and BM-MSC CM had similar pro-angiogenic effects on hyperoxia-exposed pulmonary microvascular endothelial cells. In vivo, newborn rats exposed to normoxia or hyperoxia (85% O₂) from postnatal day (P) 1 to 21 were given intra-tracheal (IT) BM or UCT-MSC (1 × 10⁶ cells/50 μL), or placebo (PL) on P3. Hyperoxia PL-treated rats had marked alveolar simplification, reduced lung vascular density, pulmonary vascular remodeling, and lung inflammation. In contrast, administration of both BM-MSC and UCT-MSC significantly improved alveolar structure, lung angiogenesis, pulmonary vascular remodeling, and lung inflammation. UCT-MSC hyperoxia-exposed rats however had greater improvement in some morphometric measures of alveolarization and less lung macrophage infiltration as compared to the BM-MSC-treated group. Together, these findings suggest that BM-MSC and UCT-MSC have significant lung regenerative effects in experimental BPD but UCT-MSC suppresses lung macrophage infiltration and promotes lung epithelial cell healing to a greater degree.

Mesenchymal Stem/Stromal Cells Derived from Human and Animal Perinatal Tissues-Origins, Characteristics, Signaling Pathways, and Clinical Trials

Mesenchymal stem/stromal cells (MSCs) are currently one of the most extensively researched fields due to their promising opportunity for use in regenerative medicine. There are many sources of MSCs, of which cells of perinatal origin appear to be an invaluable pool. Compared to embryonic stem cells, they are devoid of ethical conflicts because they are derived from tissues surrounding the fetus and can be safely recovered from medical waste after delivery. Additionally, perinatal MSCs exhibit better self-renewal and differentiation properties than those derived from adult tissues. It is important to consider the anatomy of perinatal tissues and the general description of MSCs, including their isolation, differentiation, and characterization of different types of perinatal MSCs from both animals and humans (placenta, umbilical cord, amniotic fluid). Ultimately, signaling pathways are essential to consider regarding the clinical applications of MSCs. It is important to consider the origin of these cells, referring to the anatomical structure of the organs of origin, when describing the general and specific characteristics of the different types of MSCs as well as the pathways involved in differentiation.

The hernia sac-A suitable source for obtaining mesenchymal stem cells

Background

Inguinal hernia sac, extended tissue from peritoneum, gradually enlarged in size with hernia disease time and prolapsed tissue volume. We hypothesize that mesenchymal stem cells are present in the development of hernia sac. The current study aimed to test the hypothesis that hernia sac, which is often resected and discarded as medical waste, contains mesenchymal stem cells and thus might be a suitable source to harvest mesenchymal stem cells.

Methods

Between July 2019 and June 2020, 4 hernia sacs were resected during hernia surgery and then obtained for mesenchymal extraction using the Miltenyi gentleMACS Dissociator. The presence of mesenchymal stem cells was determined by the markers CD105, CD73, and CD90, with assessment of the expressions ≥ 95%, whereas markers CD45, CD34, CD11b, CD19, and HLA-DR were used to assess lack expression (≤ 2%). Moreover, von Kossa staining, Alcian blue staining, and Oil Red O staining were used to verify the cells' ability for differentiation.

Results

Cells retrieved from the hernia sacs displayed a spindle-shaped morphology and exhibited adherence to plastics. The cell surface immunophenotypic profile was confirmed using surface markers APC-A (CD73), FITC-A (CD90), and PerCP-Cy5-5-A (CD105), with results showing 100%, 100%, and 99.2%, respectively, strongly indicating the presence of mesenchymal stem cells. Moreover, staining of in vitro cell cultures showed in vitro differentiation of precursor cells into osteoblasts, adipocytes, and chondroblasts, suggesting positive differentiation ability and identification of mesenchymal stem cells.

Conclusion

Inguinal hernia sac is a novel source of mesenchymal stem cells that can be easily obtained and stored for future usage.

Mesenchymal stem cells and extracellular vesicles for the treatment of pain: Current status and perspectives

Mesenchymal stem/stromal cells (MSCs) are multipotent progenitor cells of mesodermal origin. Due to their capacity for self-renewal and differentiation into several cell types, MSCs have been extensively studied in experimental biology and regenerative medicine in recent years. Moreover, MSCs release extracellular vesicles (EVs), which might be partly responsible for their regenerative properties. MSCs regulate several processes in target cells via paracrine signalling, such as immunomodulation, anti-apoptotic signalling, tissue remodelling, angiogenesis and anti-fibrotic signalling. The aim of this review is to provide a detailed description of the functional properties of MSCs and EVs and their potential clinical applications, with a special focus on pain treatment. The analgesic, anti-inflammatory and regenerative properties of MSCs and EVs will be discussed for several diseases, such as neuropathic pain, osteoarthritis and spinal cord injury.

Cell Therapy in Patients with Heart Failure: A Comprehensive Review and Emerging Concepts

This review summarizes the results of clinical trials of cell therapy in patients with heart failure (HF). In contrast to acute myocardial infarction (where results have been consistently negative for more than a decade), in the setting of HF the results of Phase I–II trials are encouraging, both in ischaemic and non-ischaemic cardiomyopathy. Several well-designed Phase II studies have met their primary endpoint and demonstrated an efficacy signal, which is remarkable considering that only one dose of cells was used. That an efficacy signal was seen 6–12 months after a single treatment provides a rationale for larger, rigorous trials. Importantly, no safety concerns have emerged. Amongst the various cell types tested, mesenchymal stromal cells derived from bone marrow (BM), umbilical cord, or adipose tissue show the greatest promise. In contrast, embryonic stem cells are not likely to become a clinical therapy. Unfractionated BM cells and cardiosphere-derived cells have been abandoned. The cell products used for HF will most likely be allogeneic. New approaches, such as repeated cell treatment and intravenous delivery, may revolutionize the field. As is the case for most new therapies, the development of cell therapies for HF has been slow, plagued by multifarious problems, and punctuated by many setbacks; at present, the utility of cell therapy in HF remains to be determined. What the field needs is rigorous, well-designed Phase III trials. The most important things to move forward are to keep an open mind, avoid preconceived notions, and let ourselves be guided by the evidence.

Umbilical Cord Tissue as a Source of Young Cells for the Derivation of Induced Pluripotent Stem Cells Using Non-Integrating Episomal Vectors and Feeder-Free Conditions

The clinical application of induced pluripotent stem cells (iPSC) needs to balance the use of an autologous source that would be a perfect match for the patient against any safety or efficacy issues that might arise with using cells from an older patient or donor. Drs. Takahashi and Yamanaka and the Office of Cellular and Tissue-based Products (PMDA), Japan, have had concerns over the existence of accumulated DNA mutations in the cells of older donors and the possibility of long-term negative effects. To mitigate the risk, they have chosen to partner with the Umbilical Cord (UC) banks in Japan to source allogeneic-matched donor cells. Production of iPSCs from UC blood cells (UCB) has been successful; however, reprogramming blood cells requires cell enrichment with columns or flow cytometry and specialized growth media. These requirements add to the cost of production and increase the manipulation of the cells, which complicates the regulatory approval process. Alternatively, umbilical cord tissue mesenchymal stromal cells (CT-MSCs) have the same advantage as UCB cells of being a source of young donor cells. Crucially, CT-MSCs are easier and less expensive to harvest and grow compared to UCB cells. Here, we demonstrate that CT-MSCs can be easily isolated without expensive enzymatic treatment or columns and reprogramed well using episomal vectors, which allow for the removal of the reprogramming factors after a few passages. Together the data indicates that CT-MSCs are a viable source of donor cells for the production of clinical-grade, patient matched iPSCs.

The role of Interleukin 1 receptor antagonist in mesenchymal stem cell-based tissue repair and regeneration

Interleukin (IL)-1 receptor antagonist (IL-1Ra), a naturally occurring antagonist of IL-1α/IL-1β signaling pathways, has been attributed to the immunosuppressive effects of mesenchymal stem cells (MSCs). MSCs, in IL-1Ra-dependent manner, suppressed production of IL-1β in dermal macrophages, induced their polarization in anti-inflammatory M2 phenotype, attenuated antigen-presenting properties of dendritic cells (DCs), and promoted expansion of immunosuppressive T regulatory cells in the skin, which resulted in enhanced repair of the nonhealing wounds. Reduced activation of inflammasome and suppressed production of IL-1β in macrophages were mainly responsible for beneficial effects of MSC-derived IL-1Ra in alleviation of acute lung injury, dry eye syndrome, and corneal injury. Through the production of IL-1Ra, MSCs reduced migration of DCs to the draining lymph nodes and attenuated generation of inflammatory Th1 and Th17 cells that resulted in alleviation of fulminant hepatitis and rheumatoid arthritis. MSCs, in IL-1Ra-dependent manner, reduced liver fibrosis by suppressing production of Type I collagen in hepatic stellate cells. IL-1Ra was, at least partially, responsible for enhanced proliferation of hepatocytes and chondrocytes in MSC-treated animals with partial hepatectomy and osteoarthritis. Despite of these beneficial effects, IL-1Ra-dependent inhibition of IL-1α/IL-1β-signaling significantly increased risk of infections. Therefore, future experimental and clinical studies should delineate potential side effects of MSC-derived IL-1Ra before IL-1Ra-overexpressing MSCs could be used as a potentially new therapeutic agent for the treatment of acute and chronic inflammatory diseases.