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Despite recent advances in cancer immunotherapy, there have been limitations in cancer treatment and patient survival due to a lack of antigen recognition and immunosuppressive tumor microenvironment. To overcome this issue, we have shown that miRNA modified tumor-derived Extracellular Vesicles (mt-EVs) would be an advantageous prospect since they are tumor specific and associated antigen sources which cause increase in maturation and antigen-presenting function of dendritic cells. Also, miRNAs are promising candidates for cancer therapy because of their ability to control several host immune subsets to respond against cancer cells as well as tumor microenvironment remodeling. Here, we report that mt-EVs containing tumor specific antigens loaded with miRNAs (Let-7i, miR-142 and, miR-155) could increase the survival rate of tumor-bearing mice and induce reduction in tumor growth. Importantly, the administration of mt-EVs elicited cytotoxic T cells with increasing in IFNγ and Granzyme B production ability. Notably, intramuscular (IM) injection of let7i, miR142-EVs had a significant effect on dendritic cell (DC) maturation and T cell activation along with tumor shrinkage. Collectively, our findings suggest that administration of miRNA containing EVs may be effective immunotherapy against solid tumors.

Recent advances in cancer immunotherapy had a positive impact on the life expectancy of patients for a large range of clinical indications. With new treatment strategies and druggable targets being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. However, promising therapeutic developments face hurdles in translating preclinical findings into therapy since conventional 2D cancer models hold low clinical predictive value. HUB developed an innovative alternative, build on the discovery that adult stem cells proliferate and organise into three-dimensional organotypic structures when they are embedded into extracellular matrix. Patient specific organoids are generated from healthy and malignant tissues and stored as biobanks with high quality and reproducibility. HUB Organoids recapitulate complex characteristics of the original parental tissue, including molecular heterogeneity, and morphological and functional traits. Since cancer progression and responses to immunotherapy are governed by immune cell interactions in the tumour microenvironment, we developed an assay in which various types of tumour organoids are co-cultured with T cells modified with chimeric antigen receptors (CAR T cells) to assess the cytotoxic potential. CAR-T cell therapy has been demonstrated to be efficacious against many hematological malignancies, however therapeutic application to treat solid cancers remains challenging. Our organoid-T cell co-culture assay offers a good platform to study the response of tumour organoids on the CAR T cells and will greatly contribute to our understanding of the critical factors that determine a successful CAR T cell therapy. In collaboration with GSK, HUB tested the cytotoxicity of GSK CAR T cells which target specific target antigen on human colorectal cancer (CRC) organoids. Six HUB CRC organoid models were selected based on differential expression levels of target antigen that was confirmed by FACS antibody staining. To evaluate GSK CAR T cell mediated organoid killing, caspase 3/7 expression was monitored at various timepoints and IFNγ secretion was measured by ELISA. For control, staurosporine and nonspecific-CAR T cells were included. Detected CRC-organoid killing demonstrated to be in line with antigen expression levels, indicating the specificity of the tested CAR T cells. Nevertheless, some CRC-organoid models demonstrated more resilient to CAR T cell mediated killing and further evaluation revealed upregulation of check point molecules such as PD-L1. This study reveals that tumour organoid-T cell co-culture assay hold value for preclinical development of CAR T-cell products and for evaluating tumour-evasion strategies. Moreover, this platform could potentially predict patient specific responses to CAR- T-cell therapy. Citation Format: Soura Mardpour, Mirella Georgouli, Ana Pereira Puri, Ravit Oren, Joshua Audu-Evans, Farzin Pourfarzad, Sara Brett, Pleun Hombrink, Sylvia F. Boj. Tumour organoid-t cell co-culture assay to evaluate CAR t cell cytotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 908.

Recent advances in cancer immunotherapy had a positive impact on the life expectancy of patients for a large range of clinical indications. With new treatment strategies and druggable targets being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. However, promising therapeutic developments face hurdles in translating preclinical findings into therapy since conventional 2D cancer models hold low clinical predictive value. We developed an innovative alternative, built on the discovery that adult stem cells proliferate and organise into three-dimensional organotypic structures when they are embedded into extracellular matrix. Patient specific organoids are generated from healthy and malignant tissues and stored as biobanks with high quality and reproducibility. HUB Organoids recapitulate complex characteristics of the original parental tissue, including molecular heterogeneity, and morphological and functional traits. Since cancer progression and responses to immunotherapy are governed by immune cell interactions in the tumor microenvironment, we developed an assay in which colorectal (CRC) and non-small cell lung cancer (NSCLC) tumor organoids are co-cultured with simultaneously expanded paired tumor infiltrating lymphocytes (TIL) as a source of tumor reactive cells. Our system allows robust expansion of TIL with preserved T-cell receptor repertoires and has an establishment rate of 75%. Paired resources allow for screening of immune-modulatory therapies under physiologic conditions not depending on peptide-pulsing and allo-reactivity. For this purpose, we developed a organoid-TIL co-culture system which quantifies and characterizes tumor organoid apoptosis by combining image-based analysis with flow cytometry and cytokine release assays as measurements of T-cell cytotoxicity against tumor (and normal-matched) organoids. Our system offers a powerful tool for the development and validation of cancer immunotherapy and may help to stratify cancer patients for susceptibility of various types of immunotherapies. Citation Format: Soura Mardpour, Claudia Beaurivage, Jane Sun, Lorenz Jahn, Rene Overmeer, Lars-Eric Fielmich, Pleun Hombrink, Farzin Pourfarzad, Sylvia F. Boj. Autologous organoids and T cell co-cultures as a powerful personalized platform for immunotherapy development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 188.

Glioblastoma multiforme (GBM) is a unique aggressive tumor and mostly develops in the brain, while rarely spreading out of the central nervous system. It is associated with a high mortality rate; despite tremendous efforts having been made for effective therapy, tumor recurrence occurs with high prevalence. To elucidate the mechanisms that lead to new drug discovery, animal models of tumor progression is one of the oldest and most beneficial approaches to not only investigating the aggressive nature of the tumor, but also improving preclinical research. It is also a useful tool for predicting novel therapies' effectiveness as well as side effects. However, there are concerns that must be considered, such as the heterogeneity of tumor, biological properties, pharma dynamic, and anatomic shapes of the models, which have to be similar to humans as much as possible. Although several methods and various species have been used for this approach, the real recapitulation of the human tumor has been left under discussion. The GBM model, which has been verified in this study, has been established by using the Rat C6 cell line. By exploiting bioinformatic tools, the similarities between aberrant gene expression and pathways have been predicted. In this regard, 610 common genes and a number of pathways have been detected. Moreover, while magnetic resonance imaging analysis enables us to compare tumor features between these two specious, pathological findings provides most of the human GBM characteristics. Therefore, the present study provides genomics, pathologic, and imaging evidence for showing the similarities between human and rat GBM models.

Perianal fistulas in Crohn's disease (CD) are the main challenges in inflammatory bowel diseases (IBDs). Some of the fistulas are refractory to any therapeutic strategy. The aim of this study was to evaluate the therapeutic effects of mesenchymal stromal cells (MSCs) as a novel promising modality for the treatment of fistulizing CD.This case series clinical interventional study was conducted from 2014 to 2017 at Shariati Hospital, an IBD referral center in Tehran, Iran. Refractory adult patients with CD who had draining perianal fistulas were enrolled in this study. All patients were examined by a colorectal surgeon and the fistula imaging studies were performed by pelvic magnetic resonance imaging (MRI). After autologous bone marrow (BM) aspiration and MSCs isolation, the cells were cultured and passaged under current good manufacturing practice (cGMP) conditions. Four intra-fistula injections of cells, each containing 40×10In total, 5 patients (2 males and 3 females) were enrolled in this study. No adverse events were observed during the six-month follow-up in these patients. Both the Crohn's Disease Activity Index (CDAI) and Perianal Disease Activity Index (PDAI) scores decreased in all patients after cell injections and one patient achieved complete remission with closure of fistulas, discontinuation of fistula discharge, and closure of the external opening.Local injection of MSCs combined with fibrin glue is potentially a safe and effective therapeutic approach for complex perianal fistulas in patients with CD.

Natural killer (NK) cell therapy is one of the most promising treatments for Glioblastoma Multiforme (GBM). However, this emerging technology is limited by the availability of sufficient numbers of fully functional cells. Here, we investigated the efficacy of NK cells that were expanded and treated by interleukin-2 (IL-2) and heat shock protein 70 (HSP70), both in vitro and in vivo. Proliferation and cytotoxicity assays were used to assess the functionality of NK cells in vitro, after which treated and na&iuml, ve NK cells were administrated intracranially and systemically to compare the potential antitumor activities in our in vivo rat GBM models. In vitro assays provided strong evidence of NK cell efficacy against C6 tumor cells. In vivo tracking of NK cells showed efficient homing around and within the tumor site. Furthermore, significant amelioration of the tumor in rats treated with HSP70/Il-2-treated NK cells as compared to those subjected to nontreated NK cells, as confirmed by MRI, proved the efficacy of adoptive NK cell therapy. Moreover, results obtained with systemic injection confirmed migration of activated NK cells over the blood brain barrier and subsequent targeting of GBM tumor cells. Our data suggest that administration of HSP70/Il-2-treated NK cells may be a promising therapeutic approach to be considered in the treatment of GBM.

Mesenchymal stromal cells (MSCs) can effectively contribute to tissue regeneration inside the inflammatory microenvironment mostly through modulating immune responses. MSC-derived extracellular vesicles (MSC-EVs) display immunoregulatory functions similar to parent cells. Interactions between MSC-EVs and immune cells make them an ideal therapeutic candidate for infectious, inflammatory, and autoimmune diseases. These properties of MSC-EVs have encouraged researchers to perform extensive studies on multiple factors that mediate MSC-EVs immunomodulatory effects. Investigation of proteins involved in the complex interplay of MSC-EVs and immune cells may help us to better understand their functions. Here, we performed a comprehensive proteomic analysis of MSC-EVs that was previously reported by ExoCarta database. A total of 938 proteins were identified as MSC-EV proteome using quantitative proteomics techniques. Kyoto Encyclopedia of Genes and Genomes analysis demonstrates that ECM-receptor interaction, focal adhesion, and disease-specific pathways are enriched in MSC-EVs. By detail analysis of proteins presence in immune system process, we found that expression of some cytokines, chemokines, and chemokine receptors such as IL10, HGF, LIF, CCL2, VEGFC, and CCL20, which leads to migration of MSC-EVs to injured sites, suppression of inflammation and promotion of regeneration in inflammatory and autoimmune diseases. Also, some chemoattractant proteins such as CXCL2, CXCL8, CXCL16, DEFA1, HERC5, and IFITM2 were found in MSC-EV proteome. They may actively recruit immune cells to the proximity of MSC or MSC-EVs, may result in boosting immune response under specific circumstances, and may have protective role in infectious diseases. In this review, we summarize available information about immunomodulation of MSC-EVs with particular emphasis on their proteomics analysis.

Organoids can be regarded as a beneficial tool for discovery of new therapeutics for diabetes and/or maturation of pancreatic progenitors (PP) towards β cells. Here, we devised a strategy to enhance maturation of PP by assembly of three-dimensional (3D) pancreatic organoids (PO) containing human embryonic stem (ES) cell derivatives including ES-derived pancreatic duodenal homeobox 1 (PDX1) + early PP, mesenchymal stem cells, and endothelial cells at an optimized cell ratio, on Matrigel. The PO was placed in a 3D-printed tissue trapper and heterotopically implanted into the peritoneal cavity of immunodeficient mice where it remained for 90 days. Our results indicated that, in contrast to corresponding early PP transplants, 3D PO developed more vascularization as indicated by greater area and number of vessels, a higher number of insulin-positive cells and improvement of human C-peptide secretions. Based on our findings, PO-derived β cells could be considered a novel strategy to study human β-cell development, novel therapeutics, and regenerative medicine for diabetes.

Various somatic tissue-derived mesenchymal stromal cells (MSCs) have been considered as an attractive therapeutic tool for treatment of liver diseases in which the secretion of soluble factors or extracellular vesicles (EVs) is the most probable mechanism. The experimental application of human embryonic stem cell-derived MSC (ES-MSC) increased rapidly and showed promising results, in vitro and in vivo. However, possible therapeutic effects of human ES-MSC and their EVs on Thioacetamide (TAA)-induced chronic liver injury have not been evaluated yet. Our data indicated that human ES-MSC can significantly suppress the proliferation of peripheral blood mononuclear cells compared to bone marrow (BM)-MSC and adipose (AD)-MSC. Moreover, ES-MSC increased the secretion of anti-inflammatory cytokines (i.e., TGF-β and IL-10) and decreased IFN-γ, compared to other MSCs. ES-MSC EVs demonstrated immunomodulatory activities comparable to parental cells and ameliorated cirrhosis in TAA-induced chronic rat liver injury, that is, reduction in fibrosis and collagen density, necrosis, caspase density, portal vein diameter, and transaminitis. The gene expression analyses also showed upregulation in collagenases (MMP9 and MMP13), anti-apoptotic gene (BCL-2) and anti-inflammatory cytokines (TGF-β1 and IL-10) and down-regulation of major contributors to fibrosis (Col1α, αSMA, and TIMP1), pro-apoptotic gene (BAX) and pro-inflammatory cytokines (TNFα and IL-2) following treatment with ES-MSC and ES-MSC-EV. These results demonstrated that human ES-MSC and ES-MSC EV as an off-the-shelf product, that needs further assessment to be suggested as an allogeneic product for therapeutic applications for liver fibrosis.

Recent advances in cancer immunotherapy had a positive impact on the life expectancy of patients with a large range of clinical indications. With new treatment strategies and druggable targets being identified at an increasing pace, the number of patients eligible for cancer immunotherapy is expected to expand steadily. However, promising therapeutic developments face hurdles in translating preclinical findings into therapy. Challenges range from lack of confidence in animal cancer models, inter-tumor heterogeneity and the absence of cellular microenvironment. Hubrecht Organoid Technology (HUB) offers an innovative alternative, build on the discovery that adult stem cells proliferate and organize into three-dimensional organotypic structures when they are embedded into Matrigel. HUBOrganoids™ are generated from healthy and disease tissues and stored as “living” biobanks with high quality and reproducibility. HUB Organoids recapitulate complex characteristics of the original parental tissue, including molecular heterogeneity, and morphological and functional traits. HUB has developed organoid-T-cell co-culture systems that allow a physiologic representation of the complexity of interactions in the tumor microenvironment, which is important for evaluating the effects of novel therapies. HUB offers an innovative platform combining image-based analysis with flow cytometry to visualize and quantify T-cell-tumor interactions as well as measurements of T-cell cytotoxicity against tumor (and normal-matched) organoids for colorectal and several other cancers. Our platform offers a powerful strategy for the development and validation of cancer immunotherapy and may help to screen the efficacy of immune checkpoint blockade or bispecific antibodies. In addition, cancer organoid-T-cell co-culture may also predict the functionality of tumor-infiltrating lymphocytes (TIL) and chimeric antigen receptor (CAR)-engineered T cells. As such, our platform offers opportunities in preclinical development and could become a diagnostic tool to predict individual patient response to immunotherapy. Citation Format: Pleun Hombrink, Soura Mardpour, Ewout Spaan, Jarmil Hanrath, Farzin Pourfarzad, Jasper Mullenders, Rene Overmeer, G.J Robert, Vries, F Sylvia, Boj. Organoid-T-cell co-cultures for preclinical testing of adoptive cell and cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2977.

Extracellular vesicles derived from mesenchymal stem cells (MSC-EVs) have been widely reported as promising cell-free products that show therapeutic effects of the parental cells but not their limitations. Due to the intrinsic liver tropism of MSC-EVs, they have been widely used as therapeutics or drug carriers for treatment of liver diseases. However, rapid clearance from the target site may attenuate the efficiency of systemically administered MSC-EVs. Herein, sustained release into the peritoneum has been proposed as a new strategy to prolong the bioavailability of the MSC-EVs in the target liver. During intraperitoneal injection, clickable polyethylene glycol (PEG) macromeres were mixed with MSC-EVs to form EV-encapsulated PEG hydrogels via a fast, biocompatible click reaction. Upon biodegradation, the EV-laden hydrogels were swollen gradually to release EVs in a sustained manner over 1 month. In vivo tracking of the labeled EVs revealed that the accumulation of EVs in the liver was extended by hydrogel-mediated delivery for 1 month. Four weeks after injection in a rat model of chronic liver fibrosis, the physical and histopathological investigations of the harvested liver showed superior antifibrosis, anti-apoptosis, and regenerative effects of the EVs when delivered by the sustained systemic release (Gel-EV) to the conventional bolus injection (Free-EV). Specifically, the Gel-EV system improved the antifibrosis, anti-inflammation, anti-apoptosis, and regenerative effects of the EVs to nearly 40, 50, 40, and 50% compared to Free-EV, respectively, as was specified by quantification of the fibrotic area, α-SMA density, and caspase-3 density in the harvested tissues and ALT enzyme in serum. This study may potentiate the use of MSC-EVs as cell-free therapeutics for chronic liver failure. The sustained systemic delivery strategy may open a new paradigm to extend the effects of disease-targeting EVs over time.

Being non-immunogenic and capable of achieving major metabolic liver functions, adult-derived human liver stem/progenitor cells (ADHLSCs) are of special interest in the field of liver cell therapy. The cytokine repertoire of engrafted cells may have critical impacts on the immune response balance, particularly during cell transplantation.In this work, we analyzed the cytokinome of ADHLSCs during hepatogenic differentiation (HD) following stimulation with a mixture of inflammatory cytokines (I) in vitro and compared it to that of mature hepatocytes.Independent of their hepatic state, ADHLSCs showed no constitutive expression of pro-inflammatory cytokines, which were significantly induced by inflammation (IL-1β, IL-6, IL-8, TNFα, CCL5, IL-12a, IL-12b, IL-23p19, IL-27p28 and EBI-3). IL1-RA and IDO-1, as immunoregulatory cytokines, were highly induced in undifferentiated ADHLSCs, whereas TGF-β was downregulated by both hepatic and inflammatory events. Interestingly, TDO-1 was exclusively expressed in ADHLSCs after hepatic differentiation and enhanced by inflammatory cytokines. Compared to mature hepatocytes, hepatic-differentiated ADHLSCs showed significantly different cytokine expression patterns.By establishing the cytokinome of ADHLSCs and highlighting their immunological and inflammatory features, we can enhance our knowledge about the safety and efficiency of the transplantation strategy.

The present study assessed the effects of intraportal infusions of autologous bone marrow-derived mononuclear cells (MNCs) and/or CD133+ cells on liver function in patients with decompensated cirrhosis. We randomly assigned 27 eligible patients to a placebo, MNCs, and/or CD133+ cells. Cell infusions were performed at baseline and month 3. We considered the absolute changes in the Model for End-Stage Liver Disease (MELD) scores at months 3 and 6 after infusion as the primary outcome. The participants and those who assessed the outcomes were unaware of the treatment intervention assignments. After 6 months, 9 patients were excluded because of liver transplantation (n = 3), hepatocellular carcinoma (n = 1), loss to follow-up (n = 3), and death (n = 2). The final analysis included 4 patients from the CD133+ group, 8 from the MNC group, and 6 from the placebo group. No improvement was seen in the MELD score at month 6 using either CD133+ cells or MNC infusions compared with placebo. However, at month 3 after infusion, a trend was seen toward a higher mean absolute change in the MELD score in patients who had received CD133+ cells compared with placebo (−2.00 ± 1.87 vs. −0.13 ± 1.46; p = .08). No significant adverse events occurred in the present study. A transient improvement in the MELD score was observed in subjects treated with CD133+ cells but not in the MNC or placebo group. Although the study was not powered to make definitive conclusions, the data justify further study of CD133+ therapy in cirrhotic patients. Significance Cell therapy is a new approach in liver disease. Several clinical experiments have been reported on the safety of bone marrow-derived stem cells to treat liver disorders. However, the effectiveness of these approaches in the long-term follow-ups of patients initiated controversial discussions among the scientific community. A double-blind randomized controlled trial was designed to address this concern scientifically. A transient improvement in the patients' signs occurred; however, for a sustainable result, more work is needed. The results of multiple administrations of cells reported in the present study can be compared with the results from other single-injection studies.

Pre-clinical disease models are essential for the development of novel therapies and help better understand the molecular processes. In recent years, a novel groundbreaking technology to generate patient specific in vitro cultures based on adult stem-cell organoids, has gained widespread interest for the development of new therapies and as a predictive diagnostic tool. ASC-organoids can be generated at high efficiency from both healthy and diseased tissue (resections as well as biopsies) including most carcinomas. These patient derived cultures can be expanded for prolonged periods of time while maintaining many properties of the tissue they were derived from. At HUB, we have created comprehensive ‘living biobanks' from tumors of different origin like colon, lung, breast, pancreas and ovary. These biobanks have been characterized at the genetic and transcriptional level. These analyses have shown that our ‘living biobanks' capture disease heterogeneity at the genetic and molecular level. Because organoids can be expanded long term, drug screening is feasible in these models. HUB has developed procedures for (high-throughput) compound screening in organoids including small molecules and biologics. In this setting, organoids have been used to identify novel targets, identify lead compounds and stratify potential responders based on their genetic or molecular profile. Recent advances in the field of immuno-oncology have revolutionized the treatment for cancer patients. Despite of the improvements and due to the complex and highly regulated nature of the immune system, treatment does not have a similar effect on all tumors. We have created a co-culture model of tumor derived organoids and immune cells. In these co-cultures, the cytotoxic effect of the immune cell on the tumor can be measured in a reproducible and quantitative manner. Currently we are expanding existing co-culture models to incorporate different immune cells and organoid tumor types. In addition, organoids can serve as a patient avatar in clinical development or diagnostics. In this setting, organoids could add a functional test for therapy response in a patient centered setting providing a unique tool for personalized medicine. Citation Format: Jasper Mullenders, Annemarie Buijs, Inge Van Maanen, Carol Piani, Soura Mardpour, Hans Clevers, Rob Vries, Sylvia Boj. Patient derived organoids: Bringing the "patient in the lab" for pre-clinical and clinical development [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-008.

Glioblastoma multiforme (GBM) is among the most incurable cancers. GBMs survival rate has not markedly improved, despite new radical surgery protocols, the introduction of new anticancer drugs, new treatment protocols, and advances in radiation techniques. The low efficacy of therapy, and short interval between remission and recurrence, could be attributed to the resistance of a small fraction of tumorigenic cells to treatment. The existence and importance of cancer stem cells (CSCs) is perceived by some as controversial. Experimental evidences suggest that the presence of therapy-resistant glioblastoma stem cells (GSCs) could explain tumor recurrence and metastasis. Some scientists, including most of the authors of this review, believe that GSCs are the driving force behind GBM relapses, whereas others however, question the existence of GSCs. Evidence has accumulated indicating that non-tumorigenic cancer cells with high heterogeneity, could undergo reprogramming and become GSCs. Hence, targeting GSCs as the "root cells" initiating malignancy has been proposed to eradicate this devastating disease. Most standard treatments fail to completely eradicate GSCs, which can then cause the recurrence of the disease. To effectively target GSCs, a comprehensive understanding of the biology of GSCs as well as the mechanisms by which these cells survive during treatment and develop into new tumor, is urgently needed. Herein, we provide an overview of the molecular features of GSCs, and elaborate how to facilitate their detection and efficient targeting for therapeutic interventions. We also discuss GBM classifications based on the molecular stem cell subtypes with a focus on potential therapeutic approaches.

Mesenchymal stem cells (MSCs) are adult multipotent cells that due to their ability to homing to damaged tissues and differentiate into specialized cells, are remarkable cells in the field of regenerative medicine. It's suggested that the predominant mechanism of MSCs in tissue repair might be related to their paracrine activity. The utilization of MSCs for tissue repair is initially based on the differentiation ability of these cells; however now it has been revealed that only a small fraction of the transplanted MSCs actually fuse and survive in host tissues. Indeed, MSCs supply the microenvironment with the secretion of soluble trophic factors, survival signals and the release of extracellular vesicles (EVs) such as exosome. Also, the paracrine activity of EVs could mediate the cellular communication to induce cell- differentiation/self-renewal. Recent findings suggest that EVs released by MSCs may also be critical in the physiological function of these cells. This review provides an overview of MSC-derived extracellular vesicles as a hopeful opportunity to advance novel cell-free therapy strategies that might prevail over the obstacles and risks associated with the use of native or engineered stem cells. EVs are very stable; they can pass the biological barriers without rejection and can shuttle bioactive molecules from one cell to another, causing the exchange of genetic information and reprogramming of the recipient cells. Moreover, extracellular vesicles may provide therapeutic cargo for a wide range of diseases and cancer therapy. Key Words: Mesenchymal Stem Cells, Extracellular vesicles, Exosome, Regenerative medicine.

Background In this study, we intend to assess the safety and tolerability of intra-articular knee implantation of autologous bone marrow–derived mesenchymal stromal cells (MSCs) in patients with rheumatoid arthritis (RA) and to determine the preliminary clinical efficacy data in this population. The trial registration numbers are as follows: Royan Institute Ethics Committee: AC/91/1133; NCT01873625. Methods This single-center, randomized, triple-blind, placebo-controlled phase 1/2 clinical trial randomized RA patients with knee involvement to receive either an intra-articular knee implantation of 40 million autologous bone marrow–derived MSCs per joint or normal saline (placebo). Patients were followed up for 12 months to assess therapy outcomes. Results A total of 30 patients, 15 in the MSC group and 15 in the placebo group, enrolled in this study. There were no adverse effects reported after MSC administration or during follow-up. Patients who received MSCs had superior findings according to the Western Ontario and McMaster Universities Arthritis Index (WOMAC), visual analogue scale (VAS), time to jelling and pain-free walking distance. However, this improvement could not be significantly sustained beyond 12 months. The MSC group exhibited improved standing time (P = 0.01). In addition, the MSCs appeared to contribute to reductions in methotrexate and prednisolone use. Conclusion Intra-articular knee implantation of MSCs appeared to be safe and well tolerated. In addition, we observed a trend toward clinical efficacy. These results, in our opinion, have justified the need for further investigations over an extended assessment period with larger numbers of RA patients who have knee involvement.

Mandibular continuity defects occur after tumor resection, maxillofacial injury, or osteomyelitis. In this clinical pilot study, we report a novel method for reconstruction of mandibular continuity defect by in vivo tissue engineering. In 3 patients with critical-size mandibular bone defects, the allogenic mandibular bone scaffold was customized, loaded by ex vivo expanded mesenchymal stem cells, and transplanted into the surgical defect site. According to the bone scintigraphy, vascularized bone was identified in 2 cases. In spiral computed tomography, normal bone healing without significant bone resorption was seen at the 2 viable grafts, but at the failed construction, there was a lack of osteointegration to the adjacent host bone and a higher density in the medullary bone. According to the serial panoramic imaging, the patients with viable bone grafts had normal bone healing, whereas the other patient had progressive overall bone resorption. Our results demonstrate the feasibility of allogenic bone scaffold loaded by mesenchymal stem cells in the reconstruction of mandibular continuity defects. Although long-term results are not yet available, it may be a novel method of reconstruction and a basis for further studies.

Transplantation of mesenchymal stem cells (MSCs) in combination with pioglitazone, an agonist of peroxisome proliferator-activated receptor-γ (PPAR-γ), can reduce liver fibrosis in models of liver injury. In this study, we conducted a pilot study of intraportal infusion of autologous MSCs in combination with pioglitazone to assess safety, feasibility, and effectiveness in patients with compensated cirrhosis.Two patients with compensated cirrhosis were enrolled in this study. Intraportal autologous bone marrow-derived MSCs were transplanted twice (6 months interval) to the patients. Meanwhile, 30 mg/day pioglitazone was prescribed for 12 months. Patients were assessed at baseline and months 1, 3, 6, and 12 post-infusion.Procedural complications or any major adverse effects did not occur in this pilot study. The patients' clinical conditions remained stable with no evidence of deterioration during the course of the study. A transient improvement in the Model for End-Stage Liver Disease (MELD) score was observed at month 3 post-infusion in one patient, which eventually returned to baseline at month 12.The combination of pioglitazone with MSCs is safe and feasible. The data justify further study of the combination therapy in cirrhotic patients.

Osteoarthritis (OA) is a debilitating disease that typically affects a large number of the middle-aged and elderly population. Current treatment strategies have had limited success in these patients. This study aims to investigate the safety of treatment with autologous bone marrow (BM)-derived mesenchymal stem cells (MSCs) transplanted in patients with OA of the knee, ankle, or hip.We enrolled 18 patients with different joint involvements (knee, ankle, or hip OA) and one was lost to follow-up. BM samples were taken from the patients, after which BM-derived MSCs were isolated and cultured. Each patient received one MSC injection. Patients were followed with clinical examinations, MRI and laboratory tests at 2, 6, 12, and 30 months post-transplantation.We observed no severe adverse events such as pulmonary embolism, death, or systemic complications. A limited number of patients had very minor localized adverse effects such as rash and erythema. There were no changes in liver function, hematology, or biochemistry analyses before and after cell therapy. There was no evidence of tumor or neoplastic changes in the patients during the 30-month follow-up period. All patients exhibited therapeutic benefits such as increased walking distance, decreased visual analog scale (VAS), and total Western Ontario and McMaster Universities OA Index (WOMAC) scores which were confirmed by MRI.Our study has shown that injection of MSCs in different OA affected joints is safe and therapeutically beneficial. However, further studies are needed with larger sample sizes and longer follow-up periods to confirm these findings.

Background aims Recent studies have proposed that cellular transplantation may have some regenerative and functional efficacy in the treatment of cerebral palsy (CP); however, much remains to be understood regarding its safety, feasibility and efficacy. This study was initiated to evaluate the safety of autologous bone marrow–derived CD133+ cell intrathecal injection. Methods Children (n = 12), aged 4 to 12 years, who were diagnosed with different types of CP underwent BM aspiration. CD133+ cells were enriched from the BM samples and intrathecally injected. The Gross Motor Function Measure (GMFM-66), Gross Motor Function Classification System (GMFCS), UK FIM+FAM, Functional Independence Measure (FIM) and Functional Assessment Measure (FAM) were assessed at baseline and 6 months after the procedure. Patients' ability to balance was measured by the Berg Balance Scale (BBS), and severity of spasticity was evaluated by the Modified Ashworth Scale. Magnetic resonance imaging was done at baseline and 6 months after therapy. This study was registered in ClinicalTrials.gov ( NCT01404663 ). Results There were no adverse events detected by clinical and laboratory tests or imaging studies, with the exception of a seizure in 1 patient. A significant improvement was observed 6 months after cell transplantation versus baseline according to GMFM, GMFCS, FIM+FAM, Ashworth Scale, and BBS outcomes. Conclusions Subarachnoid injection of CD133-positive enriched bone marrow progenitor cells in children with CP is a safe approach. The results suggest a possible short-term improvement in neurological function.

Background: To date, there has been little agreement on the use of ultrasonographic parameters in predicting the long-term outcome after transplantation. This study evaluates whether ultrasonography of the graft performed in the early stage after transplantation is a valuable predictor for long-term-outcome. Objectives: The aim of this study was to evaluate the association of ultrasonographic parameters (resistive index [RI], pulsatility index[PI], end diastolic velocity [EDV], graft length and graft parenchymal volume) measured within the first week after transplantation with 6 months graft function. Patients and Methods: A cross-sectional study was performed on 91 (46 males and 45 females) living renal transplants between April 2011 and February 2013. All patients underwent an ultrasonography at the first week after transplantation. Intrarenal Doppler indices including RI, PI and EDV were measured at the interlobar artery level and the graft length and parenchymal volume were defined with gray scale ultrasonography. Graft function was estimated at 6months by glomerular filtration rate (GFR). Unpaired t-test and multivariate-linear and logistic regression analysis were used to estimate the relationship between ultrasonographic parameters and GFR. Results: Fourteen patients (15.4%) had impaired graft function after 6 months (GFR less than 60 ml/min/1.73m2). Multivariate linear regression analysis showed significant correlation between GFR at 6 months and RI, PI and EDV with a P value of 0.026, 0.016 and 0.015, respectively. Logistic regression analysis showed that GFR0.7 (odds ratio=2.20, P value=0.004) and PI>1.3 (odds ratio=2.74, P value

BACKGROUND During the resent years there has been interest in using bone marrow stem cells to treat liver cirrhosis. However, there is a potential concern for malignant transformation after stem cell therapy. The aim of this study was to evaluate the development of hepatocellular carcinoma (HCC) after autologous bone marrow stem cell transplantation for liver cirrhosis. METHODS All the patients who underwent autologous stem cell transplantation for liver cirrhosis between 2005 and 2011 at our center were enrolled. Cellular infusion was made through peripheral vein, portal vein, or hepatic artery.The patients were invited to undergo screening for hepatocellular carcinoma. The screening was made with ultrasonography and alpha-feto protein (AFP) measurement. RESULTS Thirty two patients (18 males) were included in the study. Mean age of patients was 45.7 years. Fifteen patients (47%) received mesenchymal stem cell (MSC), 9 (28%) received bone marrow mononuclear cells, 5 (16%) were given CD 133-positive bone marrow cells, and 3 (9%) patients received CD 34-positive bone marrow cells. Mean duration of follow up was 20.5months. Mean serum level of AFP was 2.8 ng/ml at baseline and 3.4ng/ml at the end of follow up (p= 0.3). One patient was found to have hepatocellular carcinoma three months after infusion of bone marrow mononuclear cells. The incidence rate for HCC was 1.8 cases per 100 person-years in this study. CONCLUSION Autologous bone marrow stem cell infusion does not appear to increase the risk of hepatocellular carcinoma. The incidence rate of HCC in this study is comparable or even less than the reported rates of HCC in cohort studies of cirrhotic patients.