Allogeneic Bone Marrow-Derived Mesenchymal Stromal Cells Promote Healing of Refractory Perianal Fistulas in Patients With Crohn's Disease

Mesenchymal stem cells and their therapeutic applications in inflammatory bowel disease

Mesenchymal stem or stromal cells (MSCs) are non-hematopoietic stem cells that facilitate tissue regeneration through mechanisms involving self-renewal and differentiation, supporting angiogenesis and tissue cell survival, and limiting inflammation. MSCs were originally identified and expanded in long-term cultures of cells from bone marrow and other organs; and their native identity was recently confined into pericytes and adventitial cells in vascularized tissue. The multipotency, as well as the trophic and immunosuppressive effects, of MSCs have prompted the rapid development of clinical applications for many diseases involving tissue inflammation and immune disorders, including inflammatory bowel disease. Although standard criteria have been established to define MSCs, their therapeutic efficacy has varied significantly among studies due to their natural heterogenicity. Thus, understanding the biological and immunological features of MSCs is critical to standardize and optimize MSCs-based therapy. In this review, we highlight the cellular and molecular mechanisms involved in MSCs-mediated tissue repair and immunosuppression. We also provide an update on the current development of MSCs-based clinical trials, with a detailed discussion of MSC-based cell therapy in inflammatory bowel disease.

Systematic review with meta-analysis: the efficacy and safety of stem cell therapy for Crohn's disease

Background and aims

Stem cell therapy (SCT) for the treatment of Crohn’s disease (CD) is still in its infancy, and whether SCT is associated with improved outcomes is unclear. We performed a meta-analysis to evaluate the efficacy and safety of patients receiving SCT.

Methods

Electronic databases were searched for studies that reported the use of stem cells for the treatment of patients with CD. Raw data from included studies were pooled for effect estimates. Subgroup analyses were performed for exploration of heterogeneity regarding all outcomes.

Results

We analyzed 21 studies comprising 514 patients with active CD. A random-effects meta-analysis of studies of SCT as systemic infusion showed 56% (95% confidence interval (CI) 33–76, n = 150) of patients achieved clinical response. Similarly, random-effects pooled rates of clinical or endoscopic remission were 46% (95% CI 25–69, n = 116) and 15% (95% CI 0–50, n = 48), respectively. A random-effects meta-analysis of all perianal CD studies showed that 57% (95% CI 44–69%, n = 251) of patients had healed fistula with SCT, with an odds ratio of 3.83 (95% CI 1.06–13.86, n = 121, P = 0.04) versus control. The pooled rate of clinical recurrence was high at 16% (95% CI 4–34, n = 101) with follow-up >12 months. The pooled rates of severe adverse events (SAEs) and SAEs related to SCT were 12% (95% CI 6–23, n = 378) and 8% (95% CI 3–18, n = 378), respectively. The Egger test suggests no publication bias existed for fistula healing (P = 0.36), but did for clinical response (P = 0.003).

Conclusions

SCT seems potentially effective and may serve as an alternative treatment for refractory active CD. Toxicity will remain the most significant barrier to systemic SCT in patients with CD.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0570-x) contains supplementary material, which is available to authorized users.

Exploring endoscopic therapy for the treatment of Crohn's disease-related fistula and abscess

Fistula and abscess represent penetrating disease phenotypes of Crohn's disease (CD) and can develop in patients with or without prior history of CD-related surgery. While CD fistula and abscess have been traditionally treated with medical and surgical therapy, the role of endoscopic therapy in this particular phenotype of CD is expanding recently, thanks to advanced endoscopic techniques and a better understanding of pathogenesis and natural history of the disease and principle of treatment. The success of endoscopic treatment for inflammatory bowel disease depends on comprehension and appreciation of principles, then techniques, followed by instrument and device. Attempts should be made to temporarily or permanently close the feeding side (or the primary) orifice at the gut, by various forms of clipping. Endoscopic fistulotomy is feasible, particularly for perianal fistula and surgery-associated distal bowel fistula. Perianal abscess can be treated with endoscopic incision and drainage and even seton placement. Endoscopic treatment for fistula and abscess as well as for stricture has become an important part of the multidisciplinary approach to complex CD.

The Therapeutic Efficacy of Tonsil-derived Mesenchymal Stem Cells in Dextran Sulfate Sodium-induced Acute Murine Colitis Model

Background/Aims

Mesenchymal stem cells (MSCs) are multipotent progenitor cells currently under investigation for its efficacy as the treatment for inflammatory bowel disease. In this study, we evaluated the efficacy of tonsil-derived mesenchymal stem cells (T-MSCs) as a novel source of mesenchymal stem cells and traced their localization in a murine model of acute colitis induced by dextran sulfate sodium (DSS).

Methods

C57BL/6 mice were randomly assigned to the following three groups: the normal control group, DSS colitis group (DSS+phosphate buffered saline), and T-MSC group (DSS+T-MSCs, 1×10⁶). The severity of colitis was assessed by determining the severity of symptoms of colitis, colon length, histopathologic grade, and levels of inflammatory cytokines. T-MSCs labeled with PKH26 were traced in vivo.

Results

The T-MSC group, compared with the DSS colitis group, showed a significantly lower disease activity index (11.3±1.5 vs. 8.3±1.9, p=0.015) at sacrifice and less reduction of body weight (-17.1±5.0% vs. -8.1±6.9%, p=0.049). In the T-MSC group, the histologic colitis score was significantly decreased compared with the DSS colitis group (22.6±3.8 vs. 17.0±3.4, p=0.039). IL-6 and IL-1β, the pro-inflammatory cytokines, were also significantly reduced after a treatment with T-MSCs. In vivo tracking revealed no PKH26-labelled T-MSCs in the colonic tissue of mice with acute colitis.

Conclusions

In the acute colitis model, we demonstrated that the administration of T-MSCs ameliorates inflammatory symptoms and histology. Moreover, the anti-inflammatory activities of T-MSCs were independent of gut homing.

Mesenchymal Stem/Stromal Cells in Regenerative Medicine: Past, Present, and Future

The concept of Regenerative Medicine combined with Cell based Therapy and Tissue Engineering represents the fourth pillar of healthcare and provides a promising approach for the treatment of serious diseases. Recently, cell based therapies are focused on the use of mesenchymal stem/stromal cells (MSCs). Human MSCs, that represent a mesoderm derived population of progenitors, are easily expanded in culture. They are capable to differentiate into osteoblasts, chondrocytes, and adipocytes and exhibit the potential to repair or regenerate damaged tissues. The best characterized source of human MSCs to date is the bone marrow; recently, fetal sources, such as amniotic fluid, umbilical cord, amniotic membranes, or placenta, have also attracted increased attention. Thus, MSCs may represent a valuable tool for tissue repair and cell therapeutic applications. To this end, the main focus of this review is to summarize and evaluate the key characteristics, the sources, and the potential use of MSCs in therapeutic approaches and modalities.

Current and emerging therapeutic targets for IBD

Various therapeutic advances have led to a paradigm shift in the clinical management of patients with IBD. The introduction of immunosuppressive (such as azathioprine) and biologic agents (such as TNF blockers) has markedly reduced the need to use corticosteroids for therapy. Furthermore, the α4β7 integrin blocker vedolizumab has been introduced for clinical IBD therapy. Moreover, various new inhibitors of cytokines (for example, IL-6-IL-6R and IL-12-IL-23 blockers or apremilast), modulators of cytokine signalling events (for example, JAK inhibitors or SMAD7 blocker), inhibitors of transcription factors (for example, GATA3 or RORγt) and new anti-adhesion and anti-T-cell-activation and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors and MAdCAM1 inhibitors, regulatory T-cell therapy and stem cells) are currently being evaluated in controlled clinical trials. This Review aims to provide a comprehensive overview about current and future therapeutic approaches for IBD therapy. Furthermore, potential mechanisms of action of these therapeutic approaches and their implications for clinical therapy in IBD are discussed.

Local application of adipose-derived mesenchymal stem cells supports the healing of fistula: prospective randomised study on rat model of fistulising Crohn's disease

OBJECTIVE

Local application of adipose-derived mesenchymal stem cells (ADSC) represents a novel approach for the management of perianal fistula in patients with Crohn's disease. A randomised study on an animal model was performed to investigate the efficacy and to detect the distribution of implanted ADSCs by bioluminescence (BLI).

MATERIALS AND METHODS

A caecostomy was used as a fistula model in 32 Lewis rats. The ADSCs were isolated from transgenic donor expressing firefly luciferase. Animals were randomly assigned to groups given injections of 4 × 10⁶ cells (n = 16, group A) or placebo (n = 16, group B) in the perifistular tissue. Fistula drainage assessment was used to evaluate the fistula healing. After application of D-luciferin, cell viability and distribution was detected using an IVIS Lumina XR camera on days 0, 2, 7, 14 and 30.

RESULTS

The fistula was identified as healed in 6 (38%) animals in group A vs. 1 case (6.3%) in group B (p = .033). The BLI was strongest immediately after administration of ADSCs 31.2 × 10⁴ (6.09-111 × 10⁴) p/s/cm²/sr. The fastest decrease was observed within the first 2 days when values fell by 50.2%. The BLI 30 days after injection was significantly higher in animals with healed fistulas - 8.23 × 10⁴ (1.18-16.9 × 10⁴) vs. 1.74 × 10⁴ (0.156-6.88 × 10⁴); p = .0393.

CONCLUSIONS

Local application of ADSCs resulted in significantly higher fistula closure rate on an animal model. BLI monitoring was proved to be feasible and showed rapid reduction of the ADSC mass after application. More viable cells were detected in animals with healed fistula at the end of the follow-up.

The neuroprotective effects of human bone marrow mesenchymal stem cells are dose-dependent in TNBS colitis

Background

The incidence of inflammatory bowel diseases (IBD) is increasing worldwide with patients experiencing severe impacts on their quality of life. It is well accepted that intestinal inflammation associates with extensive damage to the enteric nervous system (ENS), which intrinsically innervates the gastrointestinal tract and regulates all gut functions. Hence, treatments targeting the enteric neurons are plausible for alleviating IBD and associated complications. Mesenchymal stem cells (MSCs) are gaining wide recognition as a potential therapy for many diseases due to their immunomodulatory and neuroprotective qualities. However, there is a large discrepancy regarding appropriate cell doses used in both clinical trials and experimental models of disease. We have previously demonstrated that human bone marrow MSCs exhibit neuroprotective and anti-inflammatory effects in a guinea-pig model of 2,4,6-trinitrobenzene-sulfonate (TNBS)-induced colitis; but an investigation into whether this response is dose-dependent has not been conducted.

Methods

Hartley guinea-pigs were administered TNBS or sham treatment intra-rectally. Animals in the MSC treatment groups received either 1 × 10⁵, 1 × 10⁶ or 3 × 10⁶ MSCs by enema 3 hours after induction of colitis. Colon tissues were collected 72 hours after TNBS administration to assess the effects of MSC treatments on the level of inflammation and damage to the ENS by immunohistochemical and histological analyses.

Results

MSCs administered at a low dose, 1 × 10⁵ cells, had little or no effect on the level of immune cell infiltrate and damage to the colonic innervation was similar to the TNBS group. Treatment with 1 × 10⁶ MSCs decreased the quantity of immune infiltrate and damage to nerve processes in the colonic wall, prevented myenteric neuronal loss and changes in neuronal subpopulations. Treatment with 3 × 10⁶ MSCs had similar effects to 1 × 10⁶ MSC treatments.

Conclusions

The neuroprotective effect of MSCs in TNBS colitis is dose-dependent. Increasing doses higher than 1 × 10⁶ MSCs demonstrates no further therapeutic benefit than 1 × 10⁶ MSCs in preventing enteric neuropathy associated with intestinal inflammation. Furthermore, we have established an optimal dose of MSCs for future studies investigating intestinal inflammation, the enteric neurons and stem cell therapy in this model.

Efficacy of Mesenchymal Stromal Cells for Fistula Treatment of Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIM

The introduction of mesenchymal stromal cells (MSCs) has changed the management of Crohn's fistula, while it remains controversial. The aim of this study was to provide an overview of efficacy and optimum state of MSCs treatment on Crohn's fistula.

METHODS

Studies reporting MSCs treatment on Crohn's fistula were searched and included. A fixed-effects model was used to assess the efficacy of MSCs, and outcomes of healing and recurrence were used to evaluate the best states of MSCs intervention.

RESULTS

Fourteen articles were enrolled (n = 477). Pooled analysis showed MSCs had a significant efficacy compared to other treatments [risk difference: 0.21 (0.09, 0.32), P = 0.000]. Notably, after MSCs treatment, the group of Crohn's disease activity index (CDAI) baseline >150 group had a higher healing rate (HR) and a clinical response (a change in CDAI of >50 points) (79.17 ± 8.78 vs. 47.54 ± 15.90, P = 0.011) compared to CDAI baseline of <150. The duration time of CD and fistulas had a negative correlation with HR accompanied by MSC therapy (r = -0.900, -0.925). Then, a moderate dose MSCs (2-4 × 10⁷ cells/ml) had a higher HR (80.07%) and lower recurrence rate (RR 13.98%) compared to other dosages. Moreover, adipose-derived MSCs therapy had an advantage over bone marrow-derived MSCs in terms of low RR (7.4 ± 4.28 vs. 13.39 ± 0.89).

CONCLUSIONS

The evidence supported the effect of MSCs at a more appropriate time of Crohn's fistula. And CDAI baseline (the points >150) has been a candidate for evaluating effectiveness of MSCs application on Crohn's fistula.

Perianal Crohn's disease: challenges and solutions

Perianal Crohn’s disease affects a significant number of patients with Crohn’s disease and is associated with poor quality of life. The nature of the disease, compounded by presentation of various disease severities, has made the treatment of perianal Crohn’s disease difficult. The field continues to evolve with the use of both historical and contemporary solutions to address the challenges associated with it. The goal of this article is to review current literature regarding medical and surgical treatment, as well as the future directions of therapy.

Is Stem Cell Therapy Ready for Prime Time in Treatment of Inflammatory Bowel Diseases?

Autologous hematopoietic stem cell transplantation (HSCT) and mesenchymal stromal cell therapy have been proposed for patients with refractory Crohn's disease (CD) and fistulizing CD, respectively. Will these highly advanced techniques be available only for select patients, at specialized centers, or is further clinical development justified, with the aim of offering widespread, more definitive therapeutic options for often very difficult to treat disease? Patients with CD who are eligible for HSCT have typically been failed by most approved therapies, have undergone multiple surgeries, and have coped with years of disease activity and poor quality of life. The objective of HSCT is to immediately shut down the immune response and allow the transplanted stem cells to develop into self-tolerant lymphocytes. For patients with fistulizing CD, mesenchymal stromal cell therapy deposits MSCs locally, into fistulizing tracts, to down-regulate the local immune response and induce wound healing. Recent trials have produced promising results for HSCT and mesenchymal stromal cell therapy as alternatives to systemic therapies and antibiotics for patients with inflammatory bowel diseases, but are these immunotherapies ready for prime time?

Mesenchymal stem/stromal cell therapy for inflammatory bowel disease: an updated review with maintenance of remission

PURPOSE OF REVIEW

There is a need for novel therapies for inflammatory bowel diseases (IBDs) that are well tolerated and effective. Currently, mesenchymal stem/stromal cells (MSCs) are being investigated in clinical trials for treatment of IBD. In this review, we update the recently published studies with an emphasis on the long-term efficacy of MSC therapy for IBD.

RECENT FINDINGS

A cumulative body of data, including a recent phase III randomized controlled trial demonstrated excellent fistula healing in patients with refractory Crohn's perianal fistulae treated via local injections of MSCs and with a good safety profile. Follow-up studies suggest long-term efficacy of MSC therapy for complex perianal Crohn's disease fistulae; however, the efficacy decreases over time and may necessitate repeat treatment. Systemic (intravenous) therapy for luminal IBD offers a relatively well tolerated alternative but its efficacy remains unclear.

SUMMARY

Recent studies demonstrate that MSCs are well tolerated and have an excellent short-term efficacy for the management of refractory fistulizing perianal Crohn's disease. The current data suggest that its influence may 'wear off' over time. More data on larger number of patients with longer duration of follow-up in the setting of a randomized placebo controlled trial are needed to confirm these promising results. For luminal IBD, there is a need for more mechanistic studies in representative preclinical murine models, and the results of an ongoing phase III randomized controlled trial are eagerly awaited.

Review article: mesenchymal stromal cell therapy for inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic relapsing diseases in which pro-inflammatory immune cells and cytokines induce intestinal tissue damage and disability. Mesenchymal stromal cells (MSCs) exert powerful immunomodulatory effects and stimulate tissue repair.

AIM

To review the current data on mesenchymal stromal cell therapy in IBD.

METHOD

We searched PubMed and 'ClinicalTrials.gov' databases using the terms 'mesenchymal stromal cells', 'mesenchymal stem cell transplantation', 'inflammatory bowel diseases', 'Crohn disease' and 'colitis, ulcerative'. Additional publications were identified from individual article reference lists.

RESULTS

MSCs include inhibition of Th1/Th17 lymphocytes and recruitment of regulatory T lymphocytes, induction of antigen-presenting cells into a regulatory-like profile, and stimulation of epithelial cell differentiation and proliferation. More than 200 patients with refractory fistulas have been treated with local injections of MSCs, resulting in complete response in more than half, and in overall response in approximately two thirds of patients. In refractory luminal Crohn's disease, 49 cases of systemic MSC infusions have been reported, while trials with autologous MSCs resulted in mitigated responses, studies using allogeneic MSCs were promising, with around 60% of patients experiencing a response and around 40% achieving clinical remission.

CONCLUSIONS

Mesenchymal stromal cells might represent a promising therapy for IBD, especially for Crohn's disease. There remain many unsolved questions concerning the optimal origin and source of mesenchymal stromal cells, dosage and modalities of administration. Moreover, mesenchymal stromal cells still need to prove their effectiveness compared with conventional treatments in randomised controlled trials.

Mesenchymal stromal cell-based therapy: Regulatory and translational aspects in gastroenterology

The past decade has witnessed an outstanding scientific production focused towards the possible clinical applications of mesenchymal stromal cells (MSCs) in autoimmune and chronic inflammatory diseases. This raised the need of novel standards to adequately address quality, efficacy and safety issues of this advanced therapy. The development of a streamlined regulation is currently hampered by the complexity of analyzing dynamic biological entities rather than chemicals. Although numerous pieces of evidence show efficacy in reducing intestinal inflammation, some inconsistencies between the mechanisms of action of rodent vs human MSCs suggest caution before assigning translational value to preclinical studies. Preliminary evidence from clinical trials showed efficacy of MSCs in the treatment of fistulizing Crohn’s disease (CD), and preparations of heterologous MSCs for CD treatment are currently tested in ongoing clinical trials. However, safety issues, especially in long-term treatment, still require solid clinical data. In this regard, standardized guidelines for appropriate dosing and methods of infusion could enhance the likelihood to predict more accurately the number of responders and the duration of remission periods. In addition, elucidating MSC mechanisms of action could lead to novel and more reliable formulations such as those derived from the MSCs themselves (e.g., supernatants).

Human mesenchymal stem cells (MSCs) for treatment towards immune- and inflammation-mediated diseases: review of current clinical trials

Human mesenchymal stem cells (MSCs) are multilineage somatic progenitor/stem cells that have been shown to possess immunomodulatory properties in recent years. Initially met with much skepticism, MSC immunomodulation has now been well reproduced across tissue sources and species to be clinically relevant. This has opened up the use of these versatile cells for application as 3rd party/allogeneic use in cell replacement/tissue regeneration, as well as for immune- and inflammation-mediated disease entities. Most surprisingly, use of MSCs for in immune-/inflammation-mediated diseases appears to yield more efficacy than for regenerative medicine, since engraftment of the exogenous cell does not appear necessary. In this review, we focus on this non-traditional clinical use of a tissue-specific stem cell, and highlight important findings and trends in this exciting area of stem cell therapy.

The Gastroenterologist's Role in Management of Perianal Fistula

Perianal fistula occurs frequently in the Crohn disease population. Therapy for fistulas has changed through the years from primarily surgical management to multidisciplinary management among gastroenterologists, radiologists, and surgeons. Gastroenterologists play a role in assisting with diagnosis through endoscopic ultrasound and assessment of luminal disease activity, providing medical therapy including biologic therapy and antibiotics, and coordinating the multidisciplinary care with surgical and radiologic colleagues.

Expanded allogeneic adipose-derived mesenchymal stem cells (Cx601) for complex perianal fistulas in Crohn's disease: a phase 3 randomised, double-blind controlled trial

BACKGROUND

Complex perianal fistulas in Crohn's disease are challenging to treat. Allogeneic, expanded, adipose-derived stem cells (Cx601) are a promising new therapeutic approach. We aimed to assess the safety and efficacy of Cx601 for treatment-refractory complex perianal fistulas in patients with Crohn's disease.

METHODS

We did this randomised, double-blind, parallel-group, placebo-controlled study at 49 hospitals in seven European countries and Israel from July 6, 2012, to July 27, 2015. Adult patients (≥18 years) with Crohn's disease and treatment-refractory, draining complex perianal fistulas were randomly assigned (1:1) using a pre-established randomisation list to a single intralesional injection of 120 million Cx601 cells or 24 mL saline solution (placebo), with stratification according to concomitant baseline treatment. Treatment was administered by an unmasked surgeon, with a masked gastroenterologist and radiologist assessing the therapeutic effect. The primary endpoint was combined remission at week 24 (ie, clinical assessment of closure of all treated external openings that were draining at baseline, and absence of collections >2 cm of the treated perianal fistulas confirmed by masked central MRI). Efficacy was assessed in the intention-to-treat (ITT) and modified ITT populations; safety was assessed in the safety population. This study is registered with ClinicalTrials.gov, number NCT01541579.

FINDINGS

212 patients were randomly assigned: 107 to Cx601 and 105 to placebo. A significantly greater proportion of patients treated with Cx601 versus placebo achieved combined remission in the ITT (53 of 107 [50%] vs 36 of 105 [34%]; difference 15·2%, 97·5% CI 0·2-30·3; p=0·024) and modified ITT populations (53 of 103 [51%] vs 36 of 101 [36%]; 15·8%, 0·5-31·2; p=0·021). 18 (17%) of 103 patients in the Cx601 group versus 30 (29%) of 103 in the placebo group experienced treatment-related adverse events, the most common of which were anal abscess (six in the Cx601 group vs nine in the placebo group) and proctalgia (five vs nine).

INTERPRETATION

Cx601 is an effective and safe treatment for complex perianal fistulas in patients with Crohn's disease who did not respond to conventional or biological treatments, or both.

FUNDING

TiGenix.

The safety of autologous and metabolically fit bone marrow mesenchymal stromal cells in medically refractory Crohn's disease - a phase 1 trial with three doses

BACKGROUND

Mesenchymal stromal cells ability to reset immune functionalities may be useful in Crohn's disease.

AIM

To perform a first-in-human phase 1 safety clinical trial of metabolically fit autologous bone marrow-derived mesenchymal stromal cells in 12 subjects with Crohn's disease utilising three doses.

METHODS

Autologous mesenchymal stromal cells were derived from marrow aspirate and propagated for 2-3 weeks with fibrinogen depleted human platelet lysate and subsequently administered to subjects without interval cryobanking. Twelve subjects received a single mesenchymal stromal cell intravenous infusion of 2, 5 or 10 million cells/kg BW(n = 4/group). Infused mesenchymal stromal cells were analysed for cell surface marker expression, IDO(indoleamine 2,3-dioxygenase) upregulation by IFNγ stimulation, and inhibition of third party peripheral blood mononuclear cell proliferation in vitro. The primary end point measured was safety and tolerability; clinical response was assessed as a secondary endpoint.

RESULTS

All patients tolerated the mesenchymal stromal cell infusion well and no dose limiting toxicity was seen. Seven patients had serious adverse events of which five were hospitalisations for Crohn's disease flare. Two of these serious adverse events were possibly related to the mesenchymal stromal cells infusion. Five subjects showed clinical response 2 weeks after the infusion. Mesenchymal stromal cell phenotype, cytokine responsiveness, and peripheral blood mononuclear cell proliferation blockade were not different among the patients.

CONCLUSION

Single infusion of fresh autologous bone marrow mesenchymal stromal cells propagated ex vivo using human platelet lysate-supplemented media was safe and feasible at intravenous doses of up to 10 million cells/kg BW in patients with Crohn's disease.

Scalable microcarrier-based manufacturing of mesenchymal stem/stromal cells

Due to their unique features, mesenchymal stem/stromal cells (MSC) have been exploited in clinical settings as therapeutic candidates for the treatment of a variety of diseases. However, the success in obtaining clinically-relevant MSC numbers for cell-based therapies is dependent on efficient isolation and ex vivo expansion protocols, able to comply with good manufacturing practices (GMP). In this context, the 2-dimensional static culture systems typically used for the expansion of these cells present several limitations that may lead to reduced cell numbers and compromise cell functions. Furthermore, many studies in the literature report the expansion of MSC using fetal bovine serum (FBS)-supplemented medium, which has been critically rated by regulatory agencies. Alternative platforms for the scalable manufacturing of MSC have been developed, namely using microcarriers in bioreactors, with also a considerable number of studies now reporting the production of MSC using xenogeneic/serum-free medium formulations. In this review we provide a comprehensive overview on the scalable manufacturing of human mesenchymal stem/stromal cells, depicting the various steps involved in the process from cell isolation to ex vivo expansion, using different cell tissue sources and culture medium formulations and exploiting bioprocess engineering tools namely microcarrier technology and bioreactors.

The role of adipose stem cells in inflammatory bowel disease: From biology to novel therapeutic strategies

Inflammatory bowel diseases are an increasing phenomenon in western countries and in growing populations. The physiopathology of these conditions is linked to intestinal stem cells homeostasis and regenerative potential in a chronic inflammatory microenvironment. Patients with IBD present an increased risk of developing colorectal cancer (CRC), or colitis associated cancer (CAC). Conventional treatment for IBD target the inflammatory process (and include anti-inflammatory and immunosuppressive drugs) with biological agents emerging as a therapeutic approach for non-responders to traditional therapy. Conventional treatment provides scarce results and present severe complications. The intestinal environment may host incoming stem cells, able to engraft in the epithelial damaged sites and differentiate. Therefore, stem cell therapies represent an emerging alternative in inflammatory bowel diseases, with current investigations on the use of haematopoietic and mesenchymal stem cells, in particular adipose stem cells, apparently fundamental as regenerators and as immune-modulators. Here, we discuss stem cells in intestinal homeostasis and as therapeutic agents for the treatment of inflammatory bowel diseases.

Stem cell-based therapies in inflammatory bowel disease: promises and pitfalls

Inflammatory bowel disease (IBD) is a chronic, often relapsing, condition that deeply impacts the quality of life for many patients. Although there have been significant advances in medical treatments, a large proportion of patients become refractory to available therapeutic options. Stem-cell therapy through hematopoietic stem cells (HSCs) or mesenchymal stem (stromal) cells (MSCs) is a promising therapeutic option for severe refractory cases especially when surgery is not feasible. In HSC transplantation, the objective is to destroy the 'autoreactive' immune cells responsible for disease chronicity, and to re-establish gut tolerance to gut microbes. In perianal Crohn's disease (CD), the objective is to deposit MSCs locally in fistulizing tracts to down-regulate the local immune response and induce wound healing. Results from upcoming and ongoing clinical trials will set the path of these novel therapeutic options that have the capability to successfully treat severe refractory Crohn's patients.

A phase I study for intravenous autologous mesenchymal stromal cell administration to patients with severe emphysema

BACKGROUND

Mesenchymal stromal cells (MSCs) may reduce inflammation and promote tissue repair in pulmonary emphysema.

AIM

To study the safety and feasibility of bone marrow-derived autologous (BM-) MSC intravenous administration to patients with severe emphysema.

DESIGN

A phase I, prospective open-label study registered at ClinicalTrials.gov as NCT01306513 Eligible patients had lung volume reduction surgery (LVRS) on two separate occasions. During the first LVRS bone marrow was collected, from which MSCs were isolated and expanded ex vivo After 8 weeks, patients received two autologous MSC infusions 1 week apart, followed by the second LVRS procedure at 3 weeks after the second BM-MSC infusion.

METHODS

Up to 3 weeks after the last MSC infusion adverse events were recorded. Using immunohistochemistry and qPCR for analysis of cell and proliferation markers, emphysematous lung tissue obtained during the first surgery was compared with lung tissue obtained after the second surgical session to assess BM-MSC effects.

RESULTS

From 10 included patients three were excluded: two did not receive MSCs due to insufficient MSC culture expansion, and one had no second surgery. No adverse events related to MSC infusions occurred and lung tissue showed no fibrotic responses. After LVRS and MSC infusions alveolar septa showed a 3-fold increased expression of the endothelial marker CD31 (P  =  0.016).

CONCLUSIONS

Autologous MSC treatment in severe emphysema is feasible and safe. The increase in CD31 expression after LVRS and MSC treatment suggests responsiveness of microvascular endothelial cells in the most severely affected parts of the lung.

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.

Intestinal stem cells and intestinal homeostasis in health and in inflammation: A review

BACKGROUND

The human intestine is a complex group of organs, highly specialized in processing food and providing nutrients to the body. It is under constant threat from microbials and toxins and has therefore developed a number of protective mechanisms. One important mechanism is the constant shedding of epithelial cells into the lumen; another is the production and maintenance of a double-layered mucous boundary in which there is continuous sampling of the luminal microbiota and a persistent presence of antimicrobial enzymes. However, the gut needs commensal bacteria to effectively break down food into absorbable nutrients, which necessitates constant communication between the luminal bacteria and the intestinal immune cells in homeostasis. Disruption of homeostasis, for whatever reason, will give rise to (chronic) inflammation.

DISCUSSION

Both medical and surgical management of this disruption is discussed.

Modern Treatments and Stem Cell Therapies for Perianal Crohn's Fistulas

Crohn's disease (CD) is a complex disorder with important incidence in North America. Perianal fistulas occur in about 20% of patients with CD and are almost always classified as complex fistulas. Conventional treatment options have shown different success rates, yet there are data indicating that these approaches cannot achieve total cure and may not improve quality of life of these patients. Fibrin glue, fistula plug, topical tacrolimus, local injection of infliximab, and use of hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) are newly suggested therapies with variable success rates. Here, we aim to review these novel therapies for the treatment of complex fistulizing CD. Although initial results are promising, randomized studies are needed to prove efficacy of these approaches in curing fistulizing perianal CD.

Treatment of perianal fistulas with human embryonic stem cell-derived mesenchymal stem cells: a canine model of human fistulizing Crohn's disease

Aim: To evaluate the safety and efficacy of intralesional injection of human embryonic stem cell (hESC)-derived mesenchymal stem/stromal cells (MSCs) in canine anal furunculosis dogs. Materials & methods: Dogs naturally develop an immune-mediated disease called canine anal furunculosis, which shares many features with human fistulizing Crohn's disease. Results: The hESC-MSCs were well tolerated and 1 month postinjection, accompanied by reduced serum levels of IL-2 and IL-6, two inflammatory cytokines associated with Crohn's disease. All six dogs were found to be completely free of fistulas at 3 months postinjection. However, at 6 months, two dogs had some fistula relapse. Conclusion: Results of this study provide the first evidence of the safety and therapeutic potential of hESC-MSCs in a large animal model.