Safety and tolerability of human placenta-derived cells (PDA001) in treatment-resistant crohn's disease: a phase 1 study

Role of Mesenchymal Stem/Stromal Cells (MSCs) and MSC-Derived Extracellular Vesicles (EVs) in Prevention of Telomere Length Shortening, Cellular Senescence, and Accelerated Biological Aging

Biological aging is defined as a progressive decline in tissue function that eventually results in cell death. Accelerated biologic aging results when the telomere length is shortened prematurely secondary to damage from biological or environmental stressors, leading to a defective reparative mechanism. Stem cells therapy may have a potential role in influencing (counteract/ameliorate) biological aging and maintaining the function of the organism. Mesenchymal stem cells, also called mesenchymal stromal cells (MSCs) are multipotent stem cells of mesodermal origin that can differentiate into other types of cells, such as adipocytes, chondrocytes, and osteocytes. MSCs influence resident cells through the secretion of paracrine bioactive components such as cytokines and extracellular vesicles (EVs). This review examines the changes in telomere length, cellular senescence, and normal biological age, as well as the factors contributing to telomere shortening and accelerated biological aging. The role of MSCs-especially those derived from gestational tissues-in prevention of telomere shortening (TS) and accelerated biological aging is explored. In addition, the strategies to prevent MSC senescence and improve the antiaging therapeutic application of MSCs and MSC-derived EVs in influencing telomere length and cellular senescence are reviewed.

Characterization of CRISPR/Cas9-edited human placental allogenic stromal cells with low tissue factor expression and reduced thrombotic effects

The tissue factor (TF/CD142) expressed by mesenchymal stromal cells (MSCs) has been regarded as a safety concern in clinical applications as it may trigger thrombosis when MSCs administered intravenously. Human placental allogenic stromal cells (ASCs) are culture-expanded, undifferentiated MSC-like cells derived from full-term postpartum placenta and possess immunomodulatory and pro-angiogenic activities, however, express TF. Here we performed CRISPR/Cas9-mediated TF gene knock out (TFKO) in ASCs, leading to significantly lower TF expression, activity and thrombotic effects. ASCs' characteristics including expansion, expression of phenotypic markers and secretory profile remained unchanged in edited cells, and their immunomodulatory activities, which are functionally relevant to therapeutic applications, were not affected upon TFKO. Taken together, this study provides a feasible strategy which could improve the clinical safety features of MSC-based cell therapy by CRISRP/Cas9-mediated TF gene knock out.

Characterization of human placenta-derived exosome (pExo) as a potential osteoarthritis disease modifying therapeutic

OBJECTIVE

Human placenta-derived exosomes (pExo) were generated, characterized, and evaluated as a therapeutic candidate for the treatment of osteoarthritis (OA).

METHODS

pExo was generated from full-term human placenta tissues by sequential centrifugation, purification, and sterile filtration. Upon analysis of particle size, cytokine composition, and exosome marker expression, pExo was further tested in cell-based assays to examine its effects on human chondrocytes. In vivo therapeutic efficacies were evaluated in a medial meniscal tear/medial collateral ligament tear (MCLT + MMT) rat model, in which animals received pExo injections intraarticularly and weight bearing tests during in-life stage while histopathology and immunohistochemistry were performed as terminal endpoints.

RESULTS

pExo displayed typical particle size, expressed maker proteins of exosome, and contained proteins with pro-proliferative, pro-anabolic, anti-catabolic, or anti-inflammatory activities. In vitro, pExo promoted chondrocyte migration and proliferation dose-dependently, which may involve its activation of cell growth-related signaling pathways. Expression of inflammatory and catabolic genes induced in a cellular OA model was significantly suppressed by pExo. In the rat OA model, pExo alleviated pain burden, restored cartilage degeneration, and downregulated expressions of pro-inflammatory, catabolic, or apoptotic proteins in a dose-dependent manner.

CONCLUSIONS

Our study demonstrates that pExo has multiple potential therapeutic effects including symptom control and disease modifying characteristics. This may make it an attractive candidate for further development as an anti-OA therapeutic.

The Impact of Cellular Therapies on Gastrointestinal Diseases: Applications and Challenges

Gastrointestinal diseases are highly prevalent, and their burden significantly impacts the quality of life of affected individuals. Inflammatory and immune-mediated intestinal diseases usually have a chronic course without adequate therapeutic modalities. Although much has been reported to comprehend these diseases, many remain resistant and refractory to conventional treatment approaches. Therefore, recent approaches to cellular therapy using stem cells, like hematopoietic stem cells and mesenchymal stem cells, and other cellular immunosuppressive modalities, like T-regulatory cells, were introduced and investigated in treating gastrointestinal diseases. We aimed to conduct a literature review to discuss the applications and challenges of cellular therapeutics in gastrointestinal diseases. Evidence from published clinical trials supports the safety and efficacy of cellular treatment in different immune-mediated and inflammatory gastrointestinal diseases. They can offer a longer duration of remission, being able to adjust the dysregulated immune system. However, there are various challenges to be considered by future trials, including the limitations of current clinical trials, challenges in retrieval and application of these therapeutics, and their mutagenesis potential.

Use of Mesenchymal Stem Cells in Crohn's Disease and Perianal Fistulas: A Narrative Review

Crohn's Disease (CD), which usually leads to anal fistulas among patients, is the most important inflammatory bowel disease that causes morbidity in many people around the world. This review article proposes using MSCs as a hopeful therapeutic strategy for CD and anal fistula treatment in both preclinical and clinical conditions. Finally, darvadstrocel, a cell-based medication to treat complex anal fistulas in adults, as the only European Medicines Agency (EMA)-approved product for the treatment of anal fistulas in CD is addressed. Although several common therapies, such as surgery and anti-tumor necrosis factor-alpha (TNF-α) drugs as well as a combination of these methods is used to improve this disease, however, due to the low effectiveness of these treatments, the use of new strategies with higher efficiency is still recommended. Cell therapy is among the new emerging therapeutic strategies that have attracted great attention from clinicians due to its unique capabilities. One of the most widely used cell sources administrated in cell therapy is mesenchymal stem cell (MSC). This review article will discuss preclinical and clinical studies about MSCs as a potent and promising therapeutic option in the treatment of CD and anal fistula.

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

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

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

Stem Cell Therapy For The Treatment Of Crohn's Disease; Current Obstacles And Future Hopes. (Mini-Review)

BACKGROUND

Crohn's disease (CD) is an autoimmune disease of the gastrointestinal tract, characterized by relapsing and remitting courses. The disease is debilitating in nature with three prominent phenotypic clinical presentations; fistulizing, stenosing, and inflammatory. Stem cells offer a new hope for CD patients with modifying the immune response and progression of the healing process.

AIM

This mini-review discusses the role of stem cells in treating CD, their effectiveness as a new therapy and their current limitations faced.

METHODS

The author conducted a literature review on recent randomized controlled trials and cohort studies concerned with the topic in question using the following keywords (Crohn's Disease, perianal fistula, Stem cell therapy, mesenchymal stem cells, remission).

RESULTS

Clinical trials show that the stem cells are more effective in the CD associated complex perianal fistula than the CD enteritis. Till the time being, there are no standardized guidelines regarding; dose of stem cells used, number of doses administered, route of administration, type of stem cells used. Only one group of researchers proposed a standardized procedure for injecting mesenchymal stem cells in complex perianal fistula, according to their own experience in clinical trials. Moreover, mesenchymal stem cells and their related types (placental, adipose tissue, umbilical tissue, etc.) are the most safe and effective in clinical trials. Currently; the commercially available mesenchymal stem cells preparation (Darvadstrocel (Cx601)) is the only one approved by The United States Food and Drug Administration (FDA) for clinical use in refractory CD associated complex perianal fistula.

CONCLUSIONS

Stem cell therapy (SCT) shows promise in; inducing remission in refractory Crohn's colitis, and perianal fistula, but further research is required before SCT could be applied to clinical practice guidelines.

Stem cell therapy for Crohn's disease: systematic review and meta-analysis of preclinical and clinical studies

Background

We explored whether stem cell therapy was effective for animal models and patients with Crohn’s disease (CD).

Methods

We searched five online databases. The relative outcomes were analyzed with the aid of GetData Graph Digitizer 2.26 and Stata 16.0 software. The SYRCLE risk of bias tool and the MINORS tool were used to assess study quality.

Results

We evaluated 46 studies including 28 animal works (n = 567) and 18 human trials (n = 360). In the animal studies, the disease activity index dramatically decreased in the mesenchymal stem cell (MSC) treatment groups compared to the control group. Rats and mice receiving MSCs exhibited longer colons [mice: standardized mean difference (SMD) 2.84, P = 0.000; rats: SMD 1.44, P = 0.029], lower histopathological scores (mice: SMD − 4.58, p = 0.000; rats: SMD − 1.41, P = 0.000) and lower myeloperoxidase levels (SMD − 6.22, P = 0.000). In clinical trials, stem cell transplantation reduced the CD activity index (SMD − 2.10, P = 0.000), the CD endoscopic index of severity (SMD − 3.40, P = 0.000) and simplified endoscopy score for CD (SMD − 1.71, P = 0.000) and improved the inflammatory bowel disease questionnaire score (SMD 1.33, P = 0.305) compared to control values. CD patients maintained high remission rates for 3–24 months after transplantation.

Conclusions

Stem cell transplantation is a valuable supplementary therapy for CD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02533-0.

Phase 2a randomized controlled study investigating the safety and efficacy of PDA-002 in diabetic peripheral neuropathy

Neuropathy is a major cause of morbidity and mortality in individuals with diabetes, with no effective therapy to alter the inevitable progression of nerve damage. We hypothesized that mesenchymal stroma cell-like populations, that are characterized as immune modulators also have the potential of inducing angiogenesis and neurite outgrowth, might be useful in treating diabetic peripheral neuropathy (DPN). The aims of this study were to investigate the efficacy and safety of mesenchymal stem cell-like product (PDA-002) in treating DPN. A phase-2 randomized placebo-controlled trial was conducted in 26 patients with DPN. Treatment consisted of three rounds of intramuscular injections in one lower limb using one of the three randomized treatment arms PDA-002 (low-dose 3 × 10⁶ cells), PDA-002 (high-dose 30 × 10⁶ cells), or placebo. Three treatments per patient occurred on days 1, 29, and 57. Study endpoints included efficacy and safety of PDA-002 in treating DPN in both lower extremities following unilateral local injection. Outcome measures included intra-epidermal nerve fiber density (IENFD) up to 1 year from the day of treatment with 6-month as the primary outcome measurement. In this phase 2 study of DPN, PDA-002 was well tolerated in both doses. No significant changes were noted in IENFD in both the treated and untreated leg in the NIS-LL, NTSS-6, or UENS. Mesenchymal stem cells represent a novel mechanism for treating diabetic neuropathy and are well tolerated. Preliminary results highlight the need of further investigation of PDA-001 as a disease modifying agent for treatment of DPN.

Basic and Preclinical Research for Personalized Medicine

Basic and preclinical research founded the progress of personalized medicine by providing a prodigious amount of integrated profiling data and by enabling the development of biomedical applications to be implemented in patient-centered care and cures. If the rapid development of genomics research boosted the birth of personalized medicine, further development in omics technologies has more recently improved our understanding of the functional genome and its relevance in profiling patients’ phenotypes and disorders. Concurrently, the rapid biotechnological advancement in diverse research areas enabled uncovering disease mechanisms and prompted the design of innovative biological treatments tailored to individual patient genotypes and phenotypes. Research in stem cells enabled clarifying their role in tissue degeneration and disease pathogenesis while providing novel tools toward the development of personalized regenerative medicine strategies. Meanwhile, the evolving field of integrated omics technologies ensured translating structural genomics information into actionable knowledge to trace detailed patients’ molecular signatures. Finally, neuroscience research provided invaluable models to identify preclinical stages of brain diseases. This review aims at discussing relevant milestones in the scientific progress of basic and preclinical research areas that have considerably contributed to the personalized medicine revolution by bridging the bench-to-bed gap, focusing on stem cells, omics technologies, and neuroscience fields as paradigms.

Novel cell-based therapies in inflammatory bowel diseases: the established concept, promising results

Inflammatory bowel diseases (IBDs) are chronic and relapsing disorders that affect the quality of life in many individuals around the world. Over the past few years, the prevalence of IBDs is substantially rising which might pose a considerable social and economic burden on health systems. Progresses in the management of chronic inflammatory diseases lead to prolonged remission phase and decreased hospitalization rate. However, during treatment, many patients become refractory to conventional therapies. Recently, advanced approaches using somatic cell therapy medicinal products (SCTMPs) including immune and stem cell-based therapies have drawn many researchers' attentions. Promising results from recent trials, alongside with the emerging market indicated that these therapeutic approaches could be an alternative and promising treatment to conventional therapies. In this review, we will discuss recent advances in cell-based therapies, which have been developed for treatment of IBDs. In addition, the global emerging market and the novel products in this field are highlighted.

CELL THERAPY IN INFLAMMATORY BOWEL DISEASE

In recent years, cell-based therapies have been explored in various immune-mediated inflammatory diseases, including inflammatory bowel disease (IBD). Cell therapy is the process of introducing new cells into an organism or tissue in order to treat a disease. The most studied cellular treatment in IBD was "stem cells-based therapy", which was explored according to different protocols in terms of type of donors, stem cells sources, study design and clinical endpoints. More recently, preliminary studies have also described the clinical use of "regulatory cells", which include T-reg and Tr1 cells, and "tolerogenic" dendritic cells. Finally, induced pluripotent stem cells are the subject of an intensive preclinical research program on animal models, including those related to colitis.

Stromal Cells in the Pathogenesis of Inflammatory Bowel Disease

Up till now, research on inflammatory bowel disease [IBD] has mainly been focused on the immune cells present in the gastrointestinal tract. However, recent insights indicate that stromal cells also play an important and significant role in IBD pathogenesis. Stromal cells in the intestines regulate both intestinal epithelial and immune cell homeostasis. Different subsets of stromal cells have been found to play a role in other inflammatory diseases [e.g. rheumatoid arthritis], and these various stromal subsets now appear to carry out also specific functions in the inflamed gut in IBD. Novel potential therapies for IBD utilize, as well as target, these pathogenic stromal cells. Injection of mesenchymal stromal cells [MSCs] into fistula tracts of Crohn's disease patients is already approved and used in clinical settings. In this review we discuss the current knowledge of the role of stromal cells in IBD pathogenesis. We further outline recent attempts to modify the stromal compartment in IBD with agents that target or replace the pathogenic stroma.

Perinatal tissues and cells in tissue engineering and regenerative medicine

Perinatal tissues are an abundant source of human extracellular matrix proteins, growth factors and stem cells with proved potential use in a wide range of therapeutic applications. Due to their placental origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Additionally, as a temporary organ, placenta is usually discarded as a medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. Although some of these tissues, such as the amniotic membrane and umbilical cord, have been used in clinical practices, most of them continue to be highly under explored. This review aims to outline the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM), as well as highlight how these solutions can be used to overcome the shortage of adequate scaffolds and cell sources that currently hampers the translation of TERM strategies towards clinical settings. STATEMENT OF SIGNIFICANCE: Stem cells and extracellular matrix derived from perinatal tissues such as placenta and umbilical cord, have drawn great attention for use in a wide variety of applications in the biomedical field. Due to their origin, these tissues possess unique biological properties, including being angiogenic, anti-inflammatory, anti-fibrotic, anti-microbial and immune privileged. Also they are typically considered medical waste, thus providing an easily available, cost effective, 'unlimited' and ethical source of raw materials. This work aims to present and discuss the most relevant applications of perinatal tissues as a source of biomaterials and stem cells in the exciting fields of tissue engineering and regenerative medicine (TERM).

Dose and duration of interferon γ pre-licensing interact with donor characteristics to influence the expression and function of indoleamine-2,3-dioxygenase in mesenchymal stromal cells

Human mesenchymal stromal cells (MSCs) are a leading cell therapy candidate for the treatment of immune and inflammatory diseases due to their potent regulation of immune cells. MSC expression of indoleamine-2,3-dioxygenase (IDO) upon interferon γ (IFNγ) exposure has been proposed as both a sentinel marker and key mediator of MSC immunomodulatory potency. Rather than wait for in vivo exposure to cytokines, MSCs can be pre-licensed during manufacturing to enhance IDO expression. In this study, we systematically examine the relative role that the dose of IFNγ, the duration of pre-licensing and the donor of origin play in dictating MSC production of functional IDO. We find that across three human MSC donors, MSCs increase their expression of IDO in response to both increased dose of IFNγ and duration of pre-licensing. However, with extended pre-licensing, the expression of IDO no longer predicts MSCs ability to suppress activated peripheral blood mononuclear cells. In addition, pre-licensing dose and duration are revealed to be minor modifiers of MSCs inherent potency, and thus cannot be manipulated to boost poor donors to the levels of high-performing donors. Thus, the dose and duration of pre-licensing should be tailored to optimize performance of specific donors and an emphasis on donor selection is needed to realize significant benefits of pre-licensing.

Stem cell therapy: old challenges and new solutions

Stem cell therapy (SCT), born as therapeutic revolution to replace pharmacological treatments, remains a hope and not yet an effective solution. Accordingly, stem cells cannot be conceivable as a "canonical" drug, because of their unique biological properties. A new reorientation in this field is emerging, based on a better understanding of stem cell biology and use of cutting-edge technologies and innovative disciplines. This will permit to solve the gaps, failures, and long-term needs, such as the retention, survival and integration of stem cells, by employing pharmacology, genetic manipulation, biological or material incorporation. Consequently, the clinical applicability of SCT for chronic human diseases will be extended, as well as its effectiveness and success, leading to long-awaited medical revolution. Here, some of these aspects are summarized, reviewing and discussing recent advances in this rapidly developing research field.

Human Amniotic Mesenchymal Stem Cells Promote Endogenous Bone Regeneration

Bone regeneration has become a research hotspot and therapeutic target in the field of bone and joint medicine. Stem cell-based therapy aims to promote endogenous regeneration and improves therapeutic effects and side-effects of traditional reconstruction of significant bone defects and disorders. Human amniotic mesenchymal stem cells (hAMSCs) are seed cells with superior paracrine functions on immune-regulation, anti-inflammation, and vascularized tissue regeneration. The present review summarized the source and characteristics of hAMSCs and analyzed their roles in tissue regeneration. Next, the therapeutic effects and mechanisms of hAMSCs in promoting bone regeneration of joint diseases and bone defects. Finally, the clinical application of hAMSCs from current clinical trials was analyzed. Although more studies are needed to confirm that hAMSC-based therapy to treat bone diseases, the clinical application prospect of the approach is worth investigating.

Cell membrane and bioactive factors derived from mesenchymal stromal cells: Cell-free based therapy for inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders of the gastrointestinal tract associated with multifactorial conditions such as ulcerative colitis and Crohn’s disease. Although the underlying mechanisms of IBD remain unclear, growing evidence has shown that dysregulated immune system reactions in genetically susceptible individuals contribute to mucosal inflammation. However, conventional treatments have been effective in inducing remission of IBD but not in preventing the relapse of them. In this way, mesenchymal stromal cells (MSC) therapy has been recognized as a promising treatment for IBD due to their immunomodulatory properties, ability to differentiate into several tissues, and homing to inflammatory sites. Even so, literature is conflicted regarding the location and persistence of MSC in the body after transplantation. For this reason, recent studies have focused on the paracrine effect of the biofactors secreted by MSC, especially in relation to the immunomodulatory potential of soluble factors (cytokines, chemokines, and growth factors) and extracellular vehicles that are involved in cell communication and in the transfer of cellular material, such as proteins, lipids, and nucleic acids. Moreover, treatment with interferon-γ, tumor necrosis factor-α, and interleukin-1β causes MSC to express immunomodulatory molecules that mediate the suppression via cell-contact dependent mechanisms. Taken together, we present an overview of the role of bioactive factors and cell membrane proteins derived from MSC as a cell-free therapy that can improve IBD treatment.

Mesenchymal stromal cell therapy in intestinal diseases

PURPOSE OF REVIEW

The advent of cell therapies, mainly based on the use of mesenchymal stromal cells (MSCs), represents a great step forward in the treatment of immune-mediated conditions. Here, we focus on those intestinal disorders wherein MSCs have been applied for immunotherapeutic purposes and whose results are available.

RECENT FINDINGS

By virtue of their ability to favour both tissue regeneration and immune tolerance, together with a substantial lack of immunogenicity, MSCs have gained huge attention in the last decade. Following abundant positive experimental data, a sizable number of clinical trials using MSCs as a new treatment in chronic inflammatory intestinal diseases were carried out with promising results and several are still ongoing. The main indication was refractory Crohn's disease wherein both feasibility and safety clearly emerged when treating the luminal phenotype with intravenous infusion/s, albeit no definitive conclusion on efficacy may be drawn. By contrast, the availability of robust demonstration also on the efficacy when treating the fistulizing phenotype through local injection/s of MSCs has led to approval of the marketing of an industrial preparation (darvadstrocel).

SUMMARY

Successful clinical implementation of this attractive option is hampered by a number of obstacles arising from methodology and regulation issues, which require the institution of interdisciplinary task forces before this cell therapy becomes a bedside reality.

Human placenta-derived mesenchymal stem cells ameliorate orbital adipogenesis in female mice models of Graves' ophthalmopathy

Background

Graves’ ophthalmopathy (GO) is a complication of Graves’ disease (GD), in which orbital connective tissues become inflamed and increase in volume and orbital fibroblasts within the orbital fat and extraocular muscles differentiate into adipocytes in vitro when stimulated by hormones, several cytokines, and growth factors including TSH, IGF-1, IL-1, interferon γ, and platelet-derived growth factor. Human placental mesenchymal stem cells (hPMSCs) have immunomodulatory effects in disease pathogenesis. Although a number of studies have reported that hPMSCs can elicit therapeutic effects, these are not sufficient. Therefore, we constructed a GO animal model in order to find out the hPMSCs recovery effect.

Methods

We investigated their anti-adipogenic effects in in vitro cultures of orbital fibroblasts established from GO patients. Primary orbital fibroblasts were exposed to differentiation medium for 10 days. After being co-cultured with hPMSCs, the characteristics of orbital fibroblast were determined by Oil Red O stain and real-time PCR. Then, we explored the in vivo regulatory effects of hPMSCs in an experimental mouse model of GO. We developed the GO mouse model using immunization by leg muscle electroporation of pTriEx1.1Neo-hTSHR A-subunit plasmid. Human PMSC injection was performed into the left orbit. We also analyzed the effects of hPMSCs in the GO animal model.

Result

We found that hPMSCs inhibited a lipid accumulation and activated factors, such as ADIPONECTIN, PPARγ, C/EBPα, and TGFβ2 genes in adipogenesis-induced primary orbital fibroblasts from GO patients. Moreover, hPMSCs were highly effective at ameliorating adipogenesis in the orbital tissue of the model.

Conclusion

These data indicate that hPMSCs recover pathogenic activation of orbital fibroblasts in animals undergoing experimental GO and confirm the feasibility of applying hPMSCs as a novel treatment for GO patients.

Perspectives of the International Society for Cell & Gene Therapy Gastrointestinal Scientific Committee on the Intravenous Use of Mesenchymal Stromal Cells in Inflammatory Bowel Disease (PeMeGi)

Inflammatory bowel disease (IBD), namely, Crohn's disease and ulcerative colitis, remains a grievous and recalcitrant problem incurring significant human and health care costs, even in consideration of the growing incidence. Initial goals of care aimed to achieve the induction and maintenance of clinical remission. The advent of novel treat-to-target approaches using patient stratification, early introduction of immunosuppressants and rapid escalation to biologics or early use of combination therapy has refocused the goals of care toward the achievement of mucosal healing. This is in an attempt to preserve intestinal function, decrease hospitalization and surgery rates and improve the quality of life of affected patients. Cellular therapeutics for the treatment of IBD offers an unprecedented opportunity to change the current paradigm from single-targeted to systems-targeted therapy, trying to dampen the whole inflammatory cascade instead of a only molecule. Therefore, as we move forward, the importance of designing informative and possibly adaptive trial designs, standardizing methodologies, harmonizing goals of therapy and evaluating methods cannot be underemphasized. In this article, we review the current literature on the application of mesenchymal stromal cells for the treatment of IBD in an effort to establish a consensus on designing efficient and consistent clinical trials for the intravenous use of this cellular therapy in IBD.

Shaping the Future of Perinatal Cells: Lessons From the Past and Interpretations of the Present

Since their discovery and characterization, mesenchymal stromal cells (MSC) have been a topic of great interest in regenerative medicine. Over the last 10 years, detailed studies investigated the properties of MSC from perinatal tissues and have indicated that these cells may represent important tools for restoring tissue damage or promoting regeneration and repair of the tissue microenvironment. At first, perinatal tissue-derived MSC drew attention due to their potential differentiation capacities suggested by their early embryological origin. It is nowadays accepted that perinatal tissue-derived MSC are promising for a wide range of regenerative medicine applications because of their unique immune modulatory properties, rather than their differentiation ability. As a matter of fact, the activation and function of various cells of the innate and adaptive immune systems are suppressed and modulated by MSC from different perinatal tissues, such as human term placenta. However, the mechanisms by which they act on immune cells to facilitate tissue repair during pathological processes remain to be thoroughly elucidated to develop safe and efficient therapeutic approaches. In addition to immune modulatory ability, several other peculiar characteristics of placenta MSC, less explored and/or more debated, are being investigated. These include an understanding of the anti-microbial properties and the role of placental MSC in tumor progression. Moreover, a thorough investigation on preparation methods, bioactive factors, mechanisms of action of the cell secretome, and the development of potency assays to predict clinical efficacy of placenta MSC and their products, are necessary to provide a solid basis for their clinical application.

Placenta-Derived Adherent Stromal Cell Therapy for Hematopoietic Disorders: A Case Study of PLX-R18

The ephemeral placenta provides a noncontroversial source of young, healthy cells of both maternal and fetal origin from which cell therapy products can be manufactured. The 2 advantages of using live cells as therapeutic entities are: (a) in their environmental-responsive, multifactorial secretion profile and (b) in their activity as a “slow-release drug delivery system,” releasing secretions over a long time frame. A major difficulty in translating cell therapy to the clinic involves challenges of large-scale, robust manufacturing while maintaining product characteristics, identity, and efficacy. To address these concerns early on, Pluristem developed the PLacental eXpanded (PLX) platform, the first good manufacturing practice–approved, 3-dimensional bioreactor-based cell growth platform, to enable culture of mesenchymal-like adherent stromal cells harvested from the postpartum placenta. One of the products produced by Pluristem on this platform is PLX-R18, a product mainly comprising placental fetal cells, which is proven in vivo to alleviate radiation-induced lethality and to enhance hematopoietic cell counts after bone marrow (BM) failure. The identified mechanism of action of PLX-R18 cells is one of the cell-derived systemic pro-hematopoietic secretions, which upregulate endogenous secretions and subsequently rescue BM and peripheral blood cellularity, thereby boosting survival. PLX-R18 is therefore currently under study to treat both the hematopoietic syndrome of acute radiation (under the US Food and Drug Administration [FDA]’s Animal Rule) and the incomplete engraftment after BM transplantation (in a phase I study). In the future, they could potentially address additional hematological indications, such as aplastic anemia, myelodysplastic syndrome, primary graft failure, and acute or chronic graft versus host disease.

Stem cells for luminal, fistulizing, and perianal inflammatory bowel disease: a comprehensive updated review of the literature

Much research has been performed over the last decade on stem cell therapy as treatment for patients with inflammatory bowel disease. Hematopoietic and mesenchymal stem cells, both allogeneic (from someone else) and autologous (from own patient), have been studied with safe and efficacious results in the majority of patients treated for luminal, perianal, and/or fistulizing disease. Here in this review, we highlight all human trials that have been conducted utilizing stem cell therapy treatment in patients with inflammatory bowel disease.

Ankylosing spondylitis and mesenchymal stromal/stem cell therapy: a new therapeutic approach

Ankylosing spondylitis (AS) is an inflammatory rheumatoid disease categorized within spondyloarthropathies (SpA) and manifested by chronic spinal arthritis. Several innate and adaptive immune cells and secreted-mediators have been indicated to play a role in AS pathogenesis. Considering the limitations of current therapeutic approaches (NSAIDs, glucocorticoids, DMARDs and biologic drugs), finding new treatments with fewer side effects and high therapeutic potentials are required in AS. Mesenchymal stem cells (MSCs) with considerable immunomodulatory and regenerative properties could be able to attenuate the inflammatory responses and help tissue repair by cell-to-cell contact and secretion of soluble factors. Moreover, MSCs do not express HLA-DR, which renders them a favorable therapeutic choice for transplantation in immune-mediated disorders. In the present review, we describe immunopathogenesis and current treatments restrictions of AS. Afterwards, immunomodulatory properties and applications of MSCs in immune-mediated disorders, as well as recent findings of clinical trials involving mesenchymal stem cell therapy (MSCT) in ankylosing spondylitis, will be discussed in detail. Additional studies are required to investigate several features of MSCT such as cell origin, dosage, administration route and, specifically, the most suitable stage of disease for ideal intervention.

Umbilical Cord Mesenchymal Stem Cell Treatment for Crohn's Disease: A Randomized Controlled Clinical Trial

Background/Aims

Stem cell therapy has been applied to treat a variety of autoimmune diseases, including Crohn's disease (CD), but few studies have examined the use of umbilical cord mesenchymal stem cells (UC-MSCs). This trial sought to investigate the efficacy and safety of UC-MSCs for the treatment of CD.

Methods

Eighty-two patients who had been diagnosed with CD and had received steroid maintenance therapy for more than 6 months were included in this study. Forty-one patients were randomly selected to receive a total of four peripheral intravenous infusions of 1×10⁶ UC-MSCs/kg, with one infusion per week. Patients were followed up for 12 months. The Crohn's disease activity index (CDAI), Harvey-Bradshaw index (HBI), and corticosteroid dosage were assessed.

Results

Twelve months after treatment, the CDAI, HBI, and corticosteroid dosage had decreased by 62.5±23.2, 3.4±1.2, and 4.2±0.84 mg/day, respectively, in the UC-MSC group and by 23.6±12.4, 1.2±0.58, and 1.2±0.35 mg/day, respectively, in the control group (p＜0.01, p＜0.05, and p＜0.05 for UC-MSC vs control, respectively). Four patients developed a fever after cell infusion. No serious adverse events were observed.

Conclusions

UC-MSCs were effective in the treatment of CD and produced mild side effects.

MRI tracking of polyethylene glycol-coated superparamagnetic iron oxide-labelled placenta-derived mesenchymal stem cells toward glioblastoma stem-like cells in a mouse model

Mesenchymal stem cells (MSCs) that display homing and infiltration properties towards tumor cells are a promising cellular targeting vector for brain tumor therapy but are limited to local-regional delivery in current preclinical models. Here, we investigated whether placenta-derived MSCs (P-MSCs) are a superior cellular vector for systemic targeting of glioblastoma stem-like cells (GSCs), with an imaging modality to real-time monitor the trafficking P-MSCs to glioblastoma sites. Results demonstrated that P-MSCs had greater migratory activity towards GSCs and across blood-brain barrier compared with bone marrow-derived MSCs, and this activity was enhanced by hypoxia precondition. Chemokine ligand 5 was identified as a chemoattractant responsible for the glioblastoma tropism of P-MSCs. Polyethylene glycol-coated superparamagnetic iron oxide (PEG-SPIO) was synthesized for cellular labelling and imaging P-MSCs, displaying high cellular uptake and no cytotoxic effect on P-MSCs cell proliferation or stemness property. The homing effects of intravenously administered PEG-SPIO-labelled P-MSCs towards intracerebral GSCs were able to be detected in mice models through T2-weighted magnetic resonance imaging (MRI). This study suggests the possibility of innovative systemic P-MSC-based cell therapy for aggressive GSCs, developing a state-of-the-art theranostic technique for real-time tracking of therapeutic P-MSCs tumor infiltration through cellular MRI.

Incorporating placental tissue in cord blood banking for stem cell transplantation

INTRODUCTION

Human term placenta is comprised of various tissues from which different cells can be obtained, including hematopoietic stem cells and mesenchymal stem/stromal cells (MSCs). Areas covered: This review will discuss the possibility to incorporate placental tissue cells in cord blood banking. It will discuss general features of human placenta, with a brief review of the immune cells at the fetal-maternal interface and the different cell populations isolated from placenta, with a particular focus on MSCs. It will address the question as to why placenta-derived MSCs should be banked with their hematopoietic counterparts. It will discuss clinical trials which are studying safety and efficacy of placenta tissue-derived MSCs in selected diseases, and preclinical studies which have proven their therapeutic properties in other diseases. It will discuss banking of umbilical cord blood and raise several issues for improvement, and the applications of cord blood cells in non-malignant disorders. Expert commentary: Umbilical cord blood banking saves lives worldwide. The concomitant banking of non-hematopoietic cells from placenta, which could be applied therapeutically in the future, alone or in combination to their hematopoietic counterparts, could exploit current banking processes while laying the foundation for clinical trials exploring placenta-derived cell therapies in regenerative medicine.

Proceedings of the signature series event of the international society for cellular therapy: "Advancements in cellular therapies and regenerative medicine in digestive diseases," London, United Kingdom, May 3, 2017

A summary of the First Signature Series Event, "Advancements in Cellular Therapies and Regenerative Medicine for Digestive Diseases," held on May 3, 2017, in London, United Kingdom, is presented. Twelve speakers from three continents covered major topics in the areas of cellular therapy and regenerative medicine applied to liver and gastrointestinal medicine as well as to diabetes mellitus. Highlights from their presentations, together with an overview of the global impact of digestive diseases and a proposal for a shared online collection and data-monitoring platform tool, are included in this proceedings. Although growing evidence demonstrate the feasibility and safety of exploiting cell-based technologies for the treatment of digestive diseases, regulatory and methodological obstacles will need to be overcome before the successful implementation in the clinic of these novel attractive therapeutic strategies.

A Refractory Celiac Patient Successfully Treated With Mesenchymal Stem Cell Infusions

Type II refractory celiac disease (RCD), as defined according to the amount of aberrant intraepithelial lymphocytes, is a condition characterized by severe malabsorption syndrome and poor prognosis, with no effective treatment. Based on the regenerative and immunomodulatory properties of mesenchymal stem cells (MSCs), we investigated the feasibility, safety, and efficacy of serial infusions of autologous bone marrow-derived MSCs in a 51-year-old woman with type II RCD. Mesenchymal stem cells were isolated, expanded, and characterized following standard protocols. Monitoring of the patient's malabsorption indexes, mucosal architecture, and percentage of aberrant intraepithelial lymphocytes was scheduled for the time of enrollment, at each infusion, and after 6 months. Determination of mucosal expression of interleukin (IL)-15 and its receptor was also performed. Expansion of MSCs was feasible, and the patient underwent 4 systemic infusions of 2 × 10(6) MSCs/kg body weight 4 months apart, without adverse effects. During the treatment period, she experienced gradual and durable amelioration of her general condition, with normalization of stool frequency, body mass index, laboratory test results, and mucosal architecture. Remarkably, the expression of IL-15 and its receptor almost completely disappeared. Thus, treatment of RCD with serial MSC infusions seems promising, leading to recovery from the life-threatening condition while blocking the IL-15 pathogenic pathway.

Stem Cell Therapies in Clinical Trials: Progress and Challenges

Clinical investigations using stem cell products in regenerative medicine are addressing a wide spectrum of conditions using a variety of stem cell types. To date, there have been few reports of safety issues arising from autologous or allogeneic transplants. Many cells administered show transient presence for a few days with trophic influences on immune or inflammatory responses. Limbal stem cells have been registered as a product for eye burns in Europe and mesenchymal stem cells have been approved for pediatric graft versus host disease in Canada and New Zealand. Many other applications are progressing in trials, some with early benefits to patients.

Concise Review: Cellular Therapies: The Potential to Regenerate and Restore Tolerance in Immune-Mediated Intestinal Diseases

Chronic inflammatory enteropathies, including celiac disease, Crohn's disease, and ulcerative colitis, are lifelong disabling conditions whose cure is still an unmet need, despite the great strides made in understanding their complex pathogenesis. The advent of cellular therapies, mainly based on the use of stem cells, represents a great step forward thanks to their multitarget strategy. Both hematopoietic stem cells (HSC) and mesenchymal stem/stromal cells (MSC) have been employed in the treatment of refractory cases with promising results. The lack of immunogenicity makes MSC more suitable for therapeutic purposes as their infusion may be performed across histocompatibility locus antigen barriers without risk of rejection. The best outcome has been obtained when treating fistulizing Crohn's disease with local injections of MSC. In addition, both HSC and MSC proved successful in promoting regeneration of intestinal mucosa, and favoring the expansion of a T-cell regulatory subset. By virtue of the ability to favor mucosal homeostasis, this last cell population has been exploited in clinical trials, with inconsistent results. Finally, the recent identification of the epithelial stem cell marker has opened up the possibility of tissue engineering, with an array of potential applications for intestinal diseases. However, the underlying mechanisms of action of these interconnected therapeutic strategies are still poorly understood. It is conceivable that over the next few years their role will become clearer as the biological interactions with injured tissues and the hierarchy by which they deliver their action are unraveled through a continuous moving from bench to bedside and vice versa. Stem Cells 2016;34:1474-1486.

Recent insights into the molecular pathogenesis of Crohn's disease: a review of emerging therapeutic targets

Chronic inflammatory bowel diseases (IBDs) are a subject of great interest in gastroenterology, due to a pathological mechanism that is difficult to explain and an optimal therapeutic approach still undiscovered. Crohn's disease (CD) is one of the main entities in IBD, characterized by clinical polymorphism and great variability in the treatment response. Modern theories on the pathogenesis of CD have proven that gut microbiome and environmental factors lead to an abnormal immune response in a genetically predisposed patient. Genome-wide association studies in patients with CD worldwide revealed several genetic mutations that increase the risk of IBD and that predispose to a more severe course of disease. Gut microbiota is considered a compulsory and an essential part in the pathogenesis of CD. Intestinal dysmicrobism with excessive amounts of different bacterial strains can be found in all patients with IBD. The discovery of Escherichia coli entero-invasive on resection pieces in patients with CD now increases the likelihood of antimicrobial or vaccine-type treatments. Recent studies targeting intestinal immunology and its molecular activation pathways provide new possibilities for therapeutics. In addition to antitumor necrosis factor molecules, which were a breakthrough in IBD, improving mucosal healing and resection-free survival rate, other classes of therapeutic agents come to focus. Leukocyte adhesion inhibitors block the leukocyte homing mechanism and prevent cellular immune response. In addition to anti-integrin antibodies, chemokine receptor antagonists and SMAD7 antisense oligonucleotides have shown encouraging results in clinical trials. Micro-RNAs have demonstrated their role as disease biomarkers but it could also become useful for the treatment of IBD. Moreover, cellular therapy is another therapeutic approach under development, aimed for severe refractory CD. Other experimental treatments include intravenous immunoglobulins, exclusive enteral nutrition, and granulocyte colony-stimulating factors.

Mesenchymal stem cells and immunomodulation: current status and future prospects

The unique immunomodulatory properties of mesenchymal stem cells (MSCs) make them an invaluable cell type for the repair of tissue/ organ damage caused by chronic inflammation or autoimmune disorders. Although they hold great promise in the treatment of immune disorders such as graft versus host disease (GvHD) and allergic disorders, there remain many challenges to overcome before their widespread clinical application. An understanding of the biological properties of MSCs will clarify the mechanisms of MSC-based transplantation for immunomodulation. In this review, we summarize the preclinical and clinical studies of MSCs from different adult tissues, discuss the current hurdles to their use and propose the future development of pluripotent stem cell-derived MSCs as an approach to immunomodulation therapy.

The Long Path of Human Placenta, and Its Derivatives, in Regenerative Medicine

In the 1800s, a baby born with a caul, a remnant of the amniotic sack or fetal membranes, was thought to be lucky, special, or protected. Over time, fetal membranes lost their legendary power and were soon considered nothing more than biological waste after birth. However, placenta tissues have reclaimed their potential and since the early 1900s an increasing body of evidence has shown that these tissues have clinical benefits in a wide range of wound repair and surgical applications. Nowadays, there is a concerted effort to understand the mechanisms underlying the beneficial effects of placental tissues, and, more recently, cells derived thereof. This review will summarize the historical and current clinical applications of human placental tissues, and cells isolated from these tissues, and discuss some mechanisms thought to be responsible for the therapeutic effects observed after tissue and/or cell transplantation.

Chorion Mesenchymal Stem Cells Show Superior Differentiation, Immunosuppressive, and Angiogenic Potentials in Comparison With Haploidentical Maternal Placental Cells

Mesenchymal stem cells (MSCs) of placental origin have become increasingly translational owing to their abundance and accessibility. MSCs of different origin share several features but also present biological differences that might point to distinct clinical properties. Hence, mixing fetal and maternal cells from the same placenta can lead to contradicting results. We analyzed the biological characteristics of haploidentical MSCs isolated from fetal sources, including the umbilical cord (UC-MSCs) and chorion (Ch-MSCs), compared with maternal decidua MSCs (Dc-MSCs). All MSCs were analyzed for general stem cell properties. In addition, immunosuppressive capacity was assessed by the inhibition of T-cell proliferation, and angiogenic potential was evaluated in a Matrigel transplantation assay. The comparison between haploidentical MSCs displayed several distinct features, including (a) marked differences in the expression of CD56, (b) a higher proliferative capacity for Dc-MSCs and UC-MSCs than for Ch-MSCs, (c) a diversity of mesodermal differentiation potential in favor of fetal MSCs, (d) a higher capacity for Ch-MSCs to inhibit T-cell proliferation, and (e) superior angiogenic potential of Ch-MSCs evidenced by a higher capability to form tubular vessel-like structures and an enhanced release of hepatocyte growth factor and vascular endothelial growth factor under hypoxic conditions. Our results suggest that assessing the prevalence of fetomaternal contamination within placental MSCs is necessary to increase robustness and limit side effects in their clinical use. Finally, our work presents evidence positioning fetoplacental cells and notably Ch-MSCs in the forefront of the quest for cell types that are superior for applications in regenerative medicine.

SIGNIFICANCE

This study analyzed the biological characteristics of mesenchymal stem cells (MSCs) isolated from fetal and maternal placental origins. The findings can be summarized as follows: (a) important differences were found in the expression of CD56, (b) a different mesodermal differentiation potential was found in favor of fetal MSCs, (c) a higher immunosuppressive capacity for chorion MSCs was noted, and (d) superior angiogenic potential of Ch-MSCs was observed. These results suggest that assessing the prevalence of fetomaternal contamination within placental MSCs is necessary to increase robustness and limit side effects in their clinical use. The evidence should allow clinicians to view fetoplacental cells, notably Ch-MSCs, favorably as candidates for use in regenerative medicine.

Placental stem cells

The placenta represents a reservoir of progenitor, stem cells and epithelial cells that have been shown to differentiate into various types, including adipogenic, osteogenic, myogenic, hepatogenic, cardiac, pancreatic, endothelial, pulmonary and neurogenic lineages. This review focuses on the properties of placenta-derived cells, and it evaluates their current therapeutic applications in regenerative medicine and cell transplantations. Ongoing clinical and preclinical studies are investigating the safety and efficacy of the human amniotic epithelial cells (hAECs), human amniotic mesenchymal stromal cells (hAMSCs) and chorionic mesenchymal stromal cells (hCMSCs). The establishment of biobanks for placental stem cells will enable the translation of scientific research into the clinic. The advantage of the placenta as a cellular source is that it contains different cell lineages, such as the haematopoietic lineage that originates from the chorion, allantois and yolk sac, and the mesenchymal lineage that originates from the chorion and amnion. In this review, we address advances in placental stem cell characterization, and we explore their possible uses in cell therapy.

Different Procoagulant Activity of Therapeutic Mesenchymal Stromal Cells Derived from Bone Marrow and Placental Decidua

While therapeutic mesenchymal stromal/stem cells (MSCs) have usually been obtained from bone marrow, perinatal tissues have emerged as promising new sources of cells for stromal cell therapy. In this study, we present a first safety follow-up on our clinical experience with placenta-derived decidual stromal cells (DSCs), used as supportive immunomodulatory and regenerative therapy for patients with severe complications after allogeneic hematopoietic stem cell transplantation (HSCT). We found that DSCs are smaller, almost half the volume of MSCs, which may favor microvascular passage. DSCs also show different hemocompatibility, with increased triggering of the clotting cascade after exposure to human blood and plasma in vitro. After infusion of DSCs in HSCT patients, we observed a weak activation of the fibrinolytic system, but the other blood activation markers remained stable, excluding major adverse events. Expression profiling identified differential levels of key factors implicated in regulation of hemostasis, such as a lack of prostacyclin synthase and increased tissue factor expression in DSCs, suggesting that these cells have intrinsic blood-activating properties. The stronger triggering of the clotting cascade by DSCs could be antagonized by optimizing the cell graft reconstitution before infusion, for example, by use of low-dose heparin anticoagulant in the cell infusion buffer. We conclude that DSCs are smaller and have stronger hemostatic properties than MSCs, thus triggering stronger activation of the clotting system, which can be antagonized by optimizing the cell graft preparation before infusion. Our results highlight the importance of hemocompatibility safety testing for every novel cell therapy product before clinical use, when applied using systemic delivery.

Human Placenta-derived Cells (PDA-001) for the Treatment of Moderate-to-severe Crohn's Disease: A Phase 1b/2a Study

BACKGROUND

PDA-001 (cenplacel-L), a preparation of placenta-derived mesenchymal-like adherent cells with immunomodulatory effects, previously demonstrated safety and tolerability in an open-label Crohn's disease (CD) study. The current phase 1b/2a study evaluated the safety and efficacy of PDA-001 in subjects with moderate-to-severe CD.

METHODS

Subjects had active inflammation on colonoscopy or elevated fecal calprotectin and inadequate response to conventional therapy. Concomitant therapy with stable doses of immunomodulators and/or biologics was permitted. Subjects received 8 units of PDA-001 (1.5 × 10 cells per unit) in the phase 1b open-label study. In the phase 2a double-blind study, subjects were randomly assigned placebo, 1 unit, or 4 units of PDA-001 (2 infusions 1 wk apart). The primary endpoint was induction of clinical response (≥100 points and/or 25% decrease in Crohn's Disease Activity Index) at 4 and 6 weeks.

RESULTS

Fifty subjects were enrolled (safety analysis, 50 subjects; efficacy analysis, 48 subjects). Four subjects received 8 units of PDA-001 (phase 1b study); 46 subjects were subsequently randomized to 1 or 4 units of PDA-001 or placebo (phase 2a study). The primary endpoint was achieved in 10/28 (36%) of PDA-001 subjects compared with placebo (0%, P = 0.026). Clinical remission was achieved in 4/28 (14%) of PDA-001 subjects compared with placebo (0%, P = 0.3). One treatment-related serious adverse event occurred (systemic hypersensitivity reaction at 8 units). In the phase 2a study, serious adverse events occurred in 9/28 (32%) of PDA-001 subjects and 1/16 (7%) of placebo subjects.

CONCLUSIONS

A 2-infusion regimen of PDA-001 induced clinical response in subjects with moderate-to-severe CD. Additional studies are warranted.

Ex vivo immunosuppressive effects of mesenchymal stem cells on Crohn's disease mucosal T cells are largely dependent on indoleamine 2,3-dioxygenase activity and cell-cell contact

Introduction

Crohn’s disease (CD) is a disabling chronic enteropathy sustained by a harmful T-cell response toward antigens of the gut microbiota in genetically susceptible subjects. Growing evidence highlights the safety and possible efficacy of mesenchymal stem cells (MSCs) as a new therapeutic tool for this condition. Therefore, we aimed to investigate the effects of bone marrow-derived MSCs on pathogenic T cells with a view to clinical application.

Methods

T-cell lines from both inflamed and non-inflamed colonic mucosal specimens of CD patients and from healthy mucosa of control subjects were grown with the antigen muramyl-dipeptide in the absence or presence of donors’ MSCs. The MSC effects were evaluated in terms of T-cell viability, apoptotic rate, proliferative response, immunophenotype, and cytokine profile. The role of the indoleamine 2,3-dioxygenase (IDO) was established by adding a specific inhibitor, the 1-methyl-DL-tryptophan, and by using MSCs transfected with the small interfering RNA (siRNA) targeting IDO. The relevance of cell-cell contact was evaluated by applying transwell membranes.

Results

A significant reduction in both cell viability and proliferative response to muramyl-dipeptide, with simultaneous increase in the apoptotic rate, was found in T cells from both inflamed and non-inflamed CD mucosa when co-cultured with MSCs and was reverted by inhibiting IDO activity and expression. A reduction of the activated CD4⁺CD25⁺ subset and increase of the CD3⁺CD69⁺ population were also observed when T-cell lines from CD mucosa were co-cultured with MSCs. In parallel, an inhibitory effect was evident on the expression of the pro-inflammatory cytokines tumor necrosis factor-α, interferon-γ, interleukin-17A and -21, whereas that of the transforming growth factor-β and interleukin-6 were increased, and production of the tolerogenic molecule soluble HLA-G was high. These latter effects were almost completely eliminated by blocking the IDO, whose activity was upregulated in MSCs co-cultured with CD T cells. The use of a semipermeable membrane partially inhibited the MSC immunosuppressive effects. Finally, hardly any effects of MSCs were observed when T cells obtained from control subjects were used.

Conclusion

MSCs exert potent immunomodulant effects on antigen-specific T cells in CD through a complex paracrine and cell-cell contact-mediated action, which may be exploited for widespread therapeutic use.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0122-1) contains supplementary material, which is available to authorized users.

Human placenta-derived adherent cells improve cardiac performance in mice with chronic heart failure

Human placenta-derived adherent cells (PDACs) are a culture-expanded, undifferentiated mesenchymal-like population derived from full-term placental tissue, with immunomodulatory, anti-inflammatory, angiogenic, and neuroprotective properties. PDA-001 (cenplacel-L), an intravenous formulation of PDAC cells, is in clinical development for the treatment of autoimmune and inflammatory diseases. We tested the therapeutic effects of PDA-001 in mice with chronic heart failure (CHF). Three weeks after transaortic constriction surgery to induce CHF, the mice underwent direct intramyocardial (IM) or i.v. injection of PDA-001 at a high (0.5 × 10(6) cells per mouse), medium (0.5 × 10(5) cells per mouse), or low (0.5 × 10(4) cells per mouse) dose. The mice were sacrificed 4 weeks after treatment. Echocardiography and ventricular catheterization showed that IM injection of PDA-001 significantly improved left ventricular systolic and diastolic function compared with injection of vehicle or i.v. injection of PDA-001. IM injection of PDA-001 also decreased cardiac fibrosis, shown by trichrome staining in the vicinity of the injection sites. Low-dose treatment showed the best improvement in cardiac performance compared with the medium- and high-dose groups. In another independent study to determine the mechanism of action with bromodeoxyuridine labeling, the proliferation rates of endothelial cells and cardiomyocytes were significantly increased by low or medium IM dose PDA-001. However, no surviving PDA-001 cells were detected in the heart 1 month after injection. In vivo real-time imaging consistently revealed that the PDA-001 cells were detectable only within 2 days after IM injection of luciferase-expressing PDA-001. Together, these results have demonstrated the cardiac therapeutic potential of PDA-001, likely through a paracrine effect.