Autologous nonmyeloablative hematopoietic stem cell transplantation in patients with severe anti-TNF refractory Crohn disease: long-term follow-up. Blood. 2010;116:6123-6132. [PMID: 20837778 DOI: 10.1182/blood-2010-06-292391]

[Indications and follow-up for autologous hematopoietic stem cell transplantation in autoimmune and autoinflammatory diseases: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) organized the 7th allogeneic hematopoietic stem cell transplantation clinical practices harmonization workshop series in September 2017 in Lille, France and updated recommendations for indications and follow-up in autologous hematopoietic stem cell transplantation in autoimmune and autoinflammatory diseases, previously published under the auspices of SFGM-TC.

Hematopoietic stem cell transplantation in a severe refractory Crohn's disease patient with intestinal stoma: a case report

Background

Hematopoietic stem cell transplantation (HSCT) can be used in the treatment of patients with refractory Crohn’s disease (CD) when no alternative treatment is available. However, HSCT increases the risk of infections, in particular during the aplasia of mobilization and conditioning. Moreover, intestinal stomas in CD augment the risk of morbidity in immunocompromised patients and under aplastic conditions. The objective of this report was to describe the results of the first year after HSCT in a CD patient with an intestinal stoma.

Methods

The patient was assessed in respect to disease symptoms and endoscopic findings before the procedure and 30, 90, 180, and 365 days after HSCT.

Results

No complications were observed during mobilization and conditioning with sufficient CD34⁺ cells being harvested in just one apheresis session. Toxicity was restricted to the hematological series. Scores of all the CD indexes and the quality of life of the patient improved. However, two of three endoscopic scores remained unchanged even though improvements were found in the appearance of the lesions.

Conclusion

HSCT may be an alternative treatment for refractory CD in patients with an intestinal stoma, and a priori, carefully selected patients with stomas should not be excluded as candidates for this procedure.

Low toxicity and favorable clinical and quality of life impact after non-myeloablative autologous hematopoietic stem cell transplant in Crohn's disease

OBJECTIVE

The incidence of adverse events in myeloablative transplant protocols is high in refractory Crohn's disease; this study used low doses of cyclophosphamide. Fourteen patients were submitted to non-myeloablative autologous hematopoietic stem cell transplantation.

RESULTS

The average number of days of anemia (hemoglobin < 10 g/dL) was 5.4 ± 4.2 and 14 ± 2.4 in the mobilization and conditioning phases, respectively. The mean number of days of neutropenia (neutrophils < 0.5 × 10⁹/L) in the mobilization phase was 1.7 ± 1.5 while it was 7.6 ± 1.4 in the conditioning phase. When comparing the conditioning and mobilization phases, there was an increased number days of leukopenia (white blood cells < 1.0 × 10⁹/L), lymphocytopenia (lymphocytes < 0.5 × 10⁹/L) and thrombocytopenia (platelets < 25 × 10⁹/L). Crohn's Disease Activity Index values before the transplant ranged from 155 to 450.5 (mean 281.2 ± 79.0) and at 30 days after the procedures they ranged from 45.4 to 177 (mean 95.8 ± 35.4). Moreover, the procedure improved in overall quality of life of patients. Non-myeloablative autologous hematopoietic stem cell transplantation with lower doses of cyclophosphamide leads to lower rates of hematological toxicity and adverse events compared to protocols described in the literature. Trial registration NCT 03000296: Date 9 December 2016.

Autologous Haematopoietic Stem Cell Transplantation for Refractory Crohn's Disease: Efficacy in a Single-Centre Cohort

BACKGROUND

Haematopoietic stem cell transplantation [HSCT] is considered a therapeutic option for patients with severe Crohn's disease [CD] unresponsive to currently available therapies.

METHODS

Autologous HSCT was considered for CD patients with active disease, unresponsive or intolerant to approved medications and unsuitable for surgery. After HSCT, patients were closely followed up every 6 weeks during the first 2 years and every 6 months thereafter up to 5 years. Colonoscopy and/or magnetic resonance imaging were performed at Months 6, 12, 24, and 48 after HSCT.

RESULTS

From December 1, 2007 to December 31, 2015, 37 CD patients were assessed for HSCT. Of these, 35 patients [13 within the ASTIC trial] underwent mobilisation. Six patients did not complete the transplant for various reasons and 29 patients were finally transplanted. Patients were followed up during a median of 12 months [6-60]. At 6 months, 70% of patients achieved drug-free clinical remission (Crohn's Disease Index of Severity [CDAI] < 150). The proportion of patients in drug-free remission (CDAI < 150, Simple Endoscopic activity Score [SES]-CD < 7] was 61% at 1 year, 52% at 2 years, 47% at 3 years, 39% at 4 years, and 15% at 5 years. Patients who relapsed were re-treated and 80% regained clinical remission. Six out of the 29 [21%] required surgery. One patient died due to systemic cytomegalovirus infection 2 months after transplant.

CONCLUSIONS

HSCT is a salvage therapy for patients with extensive and refractory CD. Although relapse occurs in a majority of patients within 5 years after transplant, drug responsiveness is regained and clinical remission achieved in 80% of cases.

Targeting Specific Immunologic Pathways in Crohn's Disease

Understanding the immunologic pathways in intestinal inflammation is crucial for the development of new therapies that can maximize patient response and minimize toxicity. Targeting integrins and cytokines is intended to control leukocyte migration to effector sites or inhibit the action of proinflammatory cytokines. New approaches to preventing leukocyte migration may target integrin receptors expressed on the intestinal vascular endothelium. The interleukin (IL)-12/IL-23 pathway has been a therapeutic target of interest in controlling active Crohn's disease (CD). New therapeutic approaches in CD may involve the enhancement of anti-inflammatory cytokine pathways and modulation of cellular responses and intranuclear signals associated with intestinal inflammation.

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.

Efficacy and safety of autologous hematopoietic stem cell therapy for refractory Crohn's disease: A systematic review and meta-analysis

BACKGROUND

Autologous hematopoietic stem cell transplantation (HSCT) has been proposed for patients with refractory Crohn's disease (CD), but it is associated with mortality and adverse events; the balance between risks and benefits becomes significantly important in the therapy. The aim of the study was to assess the efficacy and safety of autologous HSCT therapy for refractory CD.

METHODS

We conducted a comprehensive search of PubMed, Embase, the Cochrane library, and Web of Science from inception to February 2017. The pooled estimate rates for efficacy and safety of refractory CD was performed by meta-analysis and reported according to the standard Cochrane guidelines and the PRISMA statement.

RESULTS

Four prospective uncontrolled cohort studies, 4 prospective case series, and 1 randomized controlled trial (RCT) were included. Autologous HSCT had a high rate of clinical and endoscopic remission in refractory CD [79.4%, 95% confidence interval (95% CI): 0.550-0.924; 81.9%, 95% CI: 0.603-0.931, respectively]. In the case of safety, it had a relatively high incidence rate of transplant-related mortality (6.4%, 95% CI: 0.028-0.140). A significant association was observed between autologous HSCT and the incidence of febrile neutropenia (83.2%, 95% CI: 0.632-0.934). About 18.5% (95% CI: 0.061-0.442) of patients with refractory CD reached clinical remission at mobilization phase. Besides, 82.1% (95% CI: 0.692-0.903) and 54.1% (95% CI: 0.261-0.797) patients with refractory CD could achieve immunosuppressive-free and steroid-free remission for at least 12 months after the therapy.

CONCLUSION

Autologous HSCT could be a complicated treatment with relatively high mortality and significantly high efficacy for refractory CD, which should be used with caution. However, more RCTs of larger samples using refined and standardized protocols and longer period of follow-up time are needed to further assess the outcomes of autologous HSCT therapy.

Hematopoietic stem cell transplantation in autoimmune disorders: From immune-regulatory processes to clinical implications

Autoimmune diseases are characterized by the development of autoreactive T- and B-cells targeting self-antigens, which eventually can result in chronic and persistent organ damage. The autologous hematopoietic stem cell transplantation (AHSCT) opened new avenues in the treatment of patients with severe, treatment-resistant autoimmune diseases. This paper reviews the immune-regulatory mechanisms behind AHSCT, and also summarizes the experiences of clinical practice related to the therapy in organ-specific and systemic autoimmune diseases. It seems that the intricate interplay of various immune competent cells with regulatory capacity control in a synergistic manner the repopulated immune system after AHSCT, which potentially leads to a significant clinical improvement in certain autoimmune diseases. However, the widespread use of AHSCT was intrinsically limited, due to the serious side-effects of conditioning treatment and relatively high treatment-related mortality; moreover, the development of new effective and safe therapeutic approaches and the dawn of biological agents further limited its indications in the last decade. Nevertheless, with an appropriate patient selection and increased experience of transplant centres, the risks can be minimized, and AHSCT remained still a reasonable choice in multiple sclerosis and systemic sclerosis when the conventional therapy failed and further progression of disease is inevitable.

Autologous stem-cell transplantation in treatment-refractory Crohn's disease: an analysis of pooled data from the ASTIC trial

BACKGROUND

The randomised controlled ASTIC trial showed no benefit of mobilisation and autologous haematopoietic stem-cell transplantation (HSCT) compared with mobilisation followed by conventional therapy using a stringent primary endpoint (steroid-free clinical remission for 3 months with no endoscopic or radiological evidence of intestinal inflammation) in patients with treatment-refractory Crohn's disease. We now assess HSCT in patients enrolled in the ASTIC trial using endpoints that are traditional for clinical trials in Crohn's disease, and identify factors that predict benefit or harm.

METHODS

Patients who underwent mobilisation and were randomly assigned to conventional therapy in the ASTIC trial were offered HSCT at 1 year and underwent complete assessment for a further year. We report analyses of the combined cohort of patients who underwent HSCT at any time during the ASTIC trial programme. The primary outcome for this analysis was 3-month steroid-free clinical remission at 1 year after HSCT (Crohn's Disease Activity Index [CDAI] <150). We also examined the degree of endoscopic healing at 1 year. Multivariate analysis was performed to identify factors associated with achieving the primary endpoint by using logistic regression, and factors associated with experiencing a serious adverse event using Poisson regression. Participants were not masked to treatment, but the adjudication panel that reviewed radiology and endoscopy was masked to allocation and visits. All patients who underwent HSCT and had data available at baseline and 1-year follow-up were included in the primary and safety analysis. This trial is registered with ClinicalTrials.gov, number NCT00297193.

FINDINGS

Between June 28, 2007, and Sept 1, 2011, 45 patients were enrolled in the ASTIC trial from 11 European transplant units. 23 patients were randomly assigned to immediate HSCT, and 22 patients were assigned to mobilisation followed by conventional care. After completion of the ASTIC trial, 17 patients from the conventional care group received HSCT. In the combined cohort, data were available for 40 patients at baseline and 38 patients at 1 year after HSCT (one patient died, one withdrew). At 1 year after HSCT, 3-month steroid-free clinical remission was seen in 13 (38%, 95% CI 22-55) of 34 patients with available data for the whole year. Complete endoscopic healting was noted in 19 (50%, 34-66) of 38 patients. On multivariate analyses, factors associated with the primary outcome were short disease duration (odds ratio [OR] 0·64, 95% CI 0·41-0·997 per year; p=0·048) and low baseline CDAI (0·82, 0·74-0·98 per 10 units; p=0·031). 76 serious adverse events occurred in 23 of 40 patients with available data. The most common serious adverse event was infection, most of which were treatment related. Smoking and perianal disease at baseline were independent factors associated with the number of serious adverse events (OR 3·07 [95% CI 1·75-5·38; p=0·0001] for smoking and 3·97 [2·17-7·25; p<0·0001] for perianal disease) on multivariate analysis.

INTERPRETATION

When assessed using endpoints traditional for clinical trials of conventional therapy in Crohn's disease, HSCT resulted in clinical and endoscopic benefit, although it was associated with a high burden of adverse events. The prognostic factors identified could allow the therapy to be targeted to patients most likely to benefit and not experience serious adverse events.

FUNDING

Broad Medical Research Program, National Institute for Health Research Senior Investigator Award, The University of Nottingham Medical School Dean's Fund, and The Nottingham University Hospitals NHS Trust Research and Development Fund.

Autologous hematopoietic stem cells for refractory Crohn's disease

INTRODUCTION

Autologous hematopoietic stem cells are gaining ground as an effective and safe treatment for treating severe refractory Crohn's disease (CD). Autologous hematopoietic stem cell therapy (AHSCT) induces resetting of the immune system by de novo regeneration of T-cell repertoire and repopulation of epithelial cells by bone-marrow derived cells to help patients achieve clinical and endoscopic remission. Areas covered: Herein, the authors discuss the use of AHSCT in treating patients with CD. Improvements in disease activity have been seen in patients with severe autoimmune disease and patients with severe CD who underwent AHSCT for a concomitant malignant hematological disease. Clinical and endoscopic remission has been achieved in patients treated with AHSCT for CD. The only randomized trial published to date, the ASTIC Trial, did not support further use of AHSCT to treat CD. Yet, critics of this trial have deemed AHSCT as a promising treatment for severe refractory CD. Expert opinion: Even with the promising evidence presented for HSCT for refractory CD, protocols need to be refined through the collaboration of GI and hemato-oncology professionals. The goal is to incorporate safe AHSCT and restore tolerance by delivering an effective immune 'cease fire' as a treatment option for severe refractory CD.

Circulating Bone Marrow-Derived CD45-/CD34+/CD133+/VEGF+ Endothelial Progenitor Cells in Adults with Crohn's Disease

BACKGROUND

Circulating endothelial progenitor cells (EPCs) are bone marrow-derived stem cells able to migrate to sites of damaged endothelium and differentiate into endothelial cells. Altered EPC level and function have been described in various inflammatory diseases and have been shown to augment vasculogenesis in murine models. Previous studies of EPC in the context of Crohn's disease (CD) have yielded conflicting results.

AIM

To determine whether the circulating levels of EPCs are changed in the context of CD.

METHODS

CD patients and healthy controls were recruited. Disease activity was assessed by CDAI. Peripheral blood mononuclear cells were isolated and EPC numbers evaluated by FACS analysis using anti-CD34, anti-VEGF receptor-2, anti-CD133, and anti-CD45 markers.

RESULTS

Eighty-three subjects, including 32 CD patients and 51 controls were recruited, including 19 (59.4 %) and 23 (45 %) males (p = 0.26), aged 34.8 ± 14.9 and 43.3 ± 18.5 years (p = 0.64), in cases and controls, respectively. Mean CDAI was 147 ± 97, disease duration was 12.7 ± 11.1 years, and 28 (87.5 %) were receiving biologics for a mean duration of 21.7 ± 16.8 months. The mean level of peripheral EPCs in CD patients was 0.050 ± 0.086 percent and 0.007 ± 0.013 % in controls (p < 0.01). There was no significant correlation between EPC levels and age (r = -0.13, p = 0.47), CDAI (r = -0.26, p = 0.15), disease duration (r = -0.04, p = 0.84), or duration of treatment with biologics (r = 0.004, p = 0.99).

CONCLUSION

EPCs are elevated in patients with CD. Further studies are needed to examine the function of EPCs and their possible role as a marker of disease severity or therapeutic response.

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?

T-bet expression by Th cells promotes type 1 inflammation but is dispensable for colitis

The transcription factor T-bet is highly expressed by Th cells isolated from the inflamed intestine of Crohn's disease patients, and has been regarded a critical driver of murine T cell-induced colitis. However, we show here that T-bet expression by Th cells is not required for the manifestation of T-cell-induced colitis in the presence of segmented filamentous bacteria and Helicobacter hepaticus. T-bet expression by Th cells controls their survival and localization, their repertoire of chemokine and chemokine receptor expression, the accumulation of monocytes and macrophages in the inflamed colon, and their differentiation to the M1 type, i.e., type 1 inflammation. Nevertheless, T-bet-deficient Th cells efficiently induce colitis, as reflected by weight loss, diarrhea, and colon histopathology. T-bet-deficient Th cells differentiate into Th1/17 cells, able to express IFN-γ and IL-17A upon restimulation. While neutralization of IL-17A exacerbated colitis induced by wild-type or T-bet-deficient Th cells, neutralization of IFN-γ completely abolished colitis.

The role of autologous haemopoietic stem cell transplantation in the treatment of autoimmune disorders

Autologous haemopoietic stem cell transplantation (HSCT) has been used for over 30 years for malignant haematological diseases, such as myeloma and lymphoma, with considerable success. More recently this procedure has been adopted as a form of high dose immunosuppression in selected patients with autoimmune diseases that are resistant to conventional therapies. Animal models have previously outlined the rationale and validity of HSCT in patients with these non-malignant, but in many cases, life-threatening conditions. Recent data have that deletion of putative autoreactive immune clones with reconstitution of a thymic driven, tolerant immune system occurs in HSCT for auto-immune patients. Two randomised control trials have confirmed that HSCT is superior to monthly cyclophosphamide in systemic sclerosis with a highly significant disease free and overall survival benefit demonstrated in the Autologous Stem cell Transplantation International Scleroderma trial. Over 2000 patients worldwide with autoimmune conditions have been treated with HSCT - the commonest indications being multiple sclerosis (MS) and systemic sclerosis. Encouraging relapse free survival of 70-80% at 4 years, in heavily pre-treated MS patients, has been demonstrated in Phase II trials. A Phase III trial in MS patients who have failed interferon is currently accruing patients. Future challenges include improvements in safety of HSCT, particularly in cardiac assessment of systemic sclerosis patients, cost-benefit analyses of HSCT compared to standard therapy and establishment of centres of excellence to continue to enhance the safety and benefit of this exciting new therapy.

Helminth Regulation of Immunity: A Three-pronged Approach to Treat Colitis

By reputation, the parasite is a pariah, an unwelcome guest. Infection with helminth parasites evokes stereotypic immune responses in humans and mice that are dominated by T helper (Th)-2 responses; thus, a hypothesis arises that infection with helminths would limit immunopathology in concomitant inflammatory disease. Although infection with some species of helminths can cause devastating disease and affect the course of microbial infections, analyses of rodent models of inflammatory disease reveal that infection with helminth parasites, or treatment with helminth extracts, can limit the severity of autoinflammatory disease, including colitis. Intriguing, but fewer, studies show that adoptive transfer of myeloid immune cells treated with helminth products/extracts in vitro can suppress inflammation. Herein, 3 facets of helminth therapy are reviewed and critiqued: treatment with viable ova or larvae, treatment with crude extracts of the worm or purified molecules, and cellular immunotherapy. The beneficial effect of helminth therapy often converges on the mobilization of IL-10 and regulatory/alternatively activated macrophages, while there are reports on transforming growth factor (TGF)-β, regulatory T cells and dendritic cells, and recent data suggest that helminth-evoked changes in the microbiota should be considered when defining anticolitic mechanisms. We speculate that if the data from animal models translate to humans, noting the heterogeneity therein, then the choice between use of viable helminth ova, helminth extracts/molecules or antigen-pulsed immune cells could be matched to disease management in defined cohorts of patients with inflammatory bowel disease.

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.

Emerging therapeutic targets and strategies in Crohn's disease

Crohn's disease (CD) is an immune-mediated inflammatory bowel disease, in which inflammation is driven by a complex interaction between the microbiota, immune cells, genes and mediators. New mechanisms of action and several cytokines have been identified as factors involved in the inflammatory process in CD, and many new molecules have been developed to treat this complex disease. New agents have been developed that target leukocyte trafficking, block or adhesion molecules for example, as well as the development of antibodies against classic inflammatory cytokines or therapies directed against IL-12/23 and Janus kinases. The development of selective mechanisms of action and targeting of different cytokines or inflammatory mediators for each patient presents the biggest challenge for the future in CD therapy. Such agents are currently at different phases of development. We aim to review the current literature data on a targeted approach in CD, which could be promising alternative approach for CD patients in the near future.

Resetting the immune response after autologous hematopoietic stem cell transplantation for autoimmune diseases

Autologous hematopoietic stem cell transplantation (AHSCT) is currently investigated as treatment for severe and refractory autoimmune diseases, such as multiple sclerosis (MS), systemic sclerosis (SSc), Crohn's disease (CD) and systemic lupus erythematosus. Randomized clinical trials in MS, SSc and CD have shown the efficacy of AHSCT to promote control of disease activity and progression, when compared to conventional treatment. The use of high dose immunosuppressive conditioning is essential to eliminate the autoimmune repertoire, and the re-infusion of autologous hematopoietic stem cells avoids long-term leucopenia by reconstitution of both immune and hematological systems. Recent studies showed that AHSCT is able to deplete the autoimmune compartment and further promote the formation of a new auto-tolerant immune repertoire, reducing the inflammatory milieu and leading to long-term clinical remission without any complementary post-graft treatment. Deep knowledge about the mechanisms of action related to AHSCT-induced remission is required for the management of possible post-AHSCT relapse and improvement of clinical protocols. This paper will review the mechanisms enrolled in the immune response resetting promoted by AHSCT in patients with autoimmune diseases.

Haematopoietic stem cell transplantation in autoimmune diseases: From basic science to clinical practice

Based on animal studies and serendipitous clinical cases, haematopoietic stem cell transplantation (HSCT) has been used since 1995 as a specific treatment for patients with severe treatment-resistant autoimmune disease (ADs). Despite other clinical developments for autoimmune diseases, including biological therapies, there has been an ongoing requirement for HSCT in some diseases and several thousand procedures have been registered in databases for a wide variety of diseases, predominantly for treatment with autologous HSCT. Currently, the main indications are multiple sclerosis, systemic sclerosis and Crohn's disease, which are supported by large series and randomised controlled trials (RCTs), whereas retrospective registry analyses support benefit in a range of rarer indications. Research into mechanisms of action has provided insight into how tolerance may be achieved with an intensive one-off treatment. In addition to the profound anti-inflammatory and immunosuppressive effects provided by the cytotoxic regimen, long-term responses in some diseases may be explained by 'resetting' the immune system through thymic reprocessing and generation of increased T-regulatory cell activity. This review aims to summarise the gradual evolution of HSCT in severe autoimmune diseases over the last 20 years, focussing on the recent publication of clinical and scientific studies, as well as evidence-based guidelines and recommendations.

Investigating cell therapy for inflammatory bowel disease

INTRODUCTION

Advances in immuno-modulatory therapies, including anti-TNF-α therapies, have greatly increased the chance to achieve long-term remission of inflammatory bowel disease (IBD) patients. However, as the importance of mucosal healing has been demonstrated in a number of clinical studies, new cell-based therapies that can regenerate and fully restore the intestinal mucosal functions are currently under development.

AREA COVERED

In this review, we feature the recent challenges of cell-based therapies that are applied to the treatment of IBD. In particular, we will focus on hematopoietic stem cells (HSC), mesenchymal stem cells (MSCs) and intestinal stem cells (ISCs) as the candidate source for cell-based therapy targeted to treat IBD. The current status, as well as the expected advantages and disadvantages of those transplantations will be summarized and discussed.

EXPERT OPINION

Transplantation of HSC, MSC and ISC may have different levels of potential in their ability to exert an immunomodulatory or pro-regenerative effect. Combined cell therapies, such as co-transplantation of MSC and ISC, may provide improved therapeutic outcome compared to transplantation of a single cell population. Those cell-based therapies may not only improve the disease activity or tissue regeneration, but may also have the potential to decrease the risk of developing colitis-associated cancers.

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.

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.

Pharmacological- and non-pharmacological therapeutic approaches in inflammatory bowel disease in adults

Inflammatory bowel diseases (IBDs) are a group of chronic inflammatory conditions mainly of the colon and small intestine. Crohn's disease (CD) and ulcerative colitis (UC) are the most frequent types of IBD. IBD is a complex disease which arises as a result of the interaction of environmental, genetic and immunological factors. It is increasingly thought that alterations of immunological reactions of the patients to their own enterable bacteria (microfilm) may contribute to inflammation. It is characterized by mucosal and sub mucosal inflammation, perpetuated by infiltration of activated leukocytes. CD may affect the whole gastrointestinal tract while UC only attacks the large intestine. The therapeutic goal is to achieve a steroid-free long lasting remission in both entities. UC has the possibility to be cured by a total colectomy, while CD never can be cured by any operation. A lifelong intake of drugs is mostly necessary and essential. Medical treatment of IBD has to be individualized to each patient and usually starts with anti-inflammatory drugs. The choice what kind of drugs and what route administered (oral, rectal, intravenous) depends on factors including the type, the localization, and severity of the patient's disease. IBD may require immune-suppression to control symptoms such as prednisolone, thiopurines, calcineurin or sometimes folic acid inhibitors or biologics like TNF-α inhibitors or anti-integrin antibodies. For both types of disease (CD, UC) the same drugs are available but they differ in their preference in efficacy between CD and UC as 5-aminosalicylic acid for UC or budesonide for ileocecal CD. As therapeutic alternative the main mediators of the disease, namely the activated pro-inflammatory cytokine producing leukocytes can be selectively removed via two apheresis systems (Adacolumn and Cellsorba) in steroid-refractory or dependent cases. Extracorporeal photopheresis results in an increase of regulatory B cells, regulatory CD8(+) T cells and T-regs Type 1. Both types of apheresis were able to induce clinical remission and mucosal healing accompanied by tapering of steroids.

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.

Crohn's disease-derived monocytes fail to induce Paneth cell defensins

Crohn's disease (CD) is associated with a multitude of genetic defects, many of which likely affect Paneth cell function. Paneth cells reside in the small intestine and produce antimicrobial peptides essential for the host barrier, principally human α-defensin 5 (HD5) and HD6. Patients with CD of the ileum are characterized by reduced constitutive expression of these peptides and, accordingly, compromised antimicrobial barrier function. Here, we present a previously unidentified regulatory mechanism of Paneth cell defensins. Using cultures of human ileal tissue, we showed that the secretome of peripheral blood mononuclear cells (PBMCs) from healthy controls restored the attenuated Paneth cell α-defensin expression characteristic of patients with ileal CD. Analysis of the Wnt pathway in both cultured biopsies and intestinal epithelial cells implicated Wnt ligands driving the PBMC effect, whereas various tested cytokines were ineffective. We further detected another defect in patients with ileal CD, because the PBMC secretomes derived from patients with CD were unable to restore the reduced HD5/HD6 expression. Accordingly, analysis of PBMC subtypes showed that monocytes of patients with CD express significantly lower levels of canonical Wnt ligands, including Wnt3, Wnt3a, Wnt1, and wntless Wnt ligand secretion mediator (Evi/Wls). These studies reveal an important cross-talk between bone marrow-derived cells and epithelial secretory Paneth cells. Defective Paneth cell-mediated innate immunity due to inadequate Wnt ligand stimulation by monocytes provides an additional mechanism in CD. Because defects of Paneth cell function stemming from various etiologies are overcome by Wnt ligands, this mechanism is a potential therapeutic target for this disease.

Targeting the delivery of systemically administered haematopoietic stem/progenitor cells to the inflamed colon using hydrogen peroxide and platelet microparticle pre-treatment strategies

Haematopoietic stem and progenitor cell (HSC) therapy may be promising for the treatment of inflammatory bowel disorders (IBDs). However, clinical success remains poor, partly explained by limited HSC recruitment following systemic delivery. The mechanisms governing HSC adhesion within inflamed colon, and whether this event can be enhanced, are not known. An immortalised HSC-like line (HPC7) was pre-treated with hydrogen peroxide (H2O2), activated platelet releasate enriched supernatant (PES) or platelet microparticles (PMPs). Subsequent adhesion was monitored using adhesion assays or in vivo ischaemia-reperfusion (IR) and colitis injured mouse colon intravitally. Integrin clustering was determined confocally and cell morphology using scanning electron microscopy. Both injuries resulted in increased HPC7 adhesion within colonic mucosal microcirculation. H2O2 and PES significantly enhanced adhesion in vitro and in the colitis, but not IR injured, colon. PMPs had no effect on adhesion. PES and PMPs induced clustering of integrins on the HPC7 surface, but did not alter their expression. Adhesion to the colon is modulated by injury but only in colitis injury can this recruitment be enhanced. The enhanced adhesion induced by PES is likely through integrin distribution changes on the HPC7 surface. Improving local HSC presence in injured colon may result in better therapeutic efficacy for treatment of IBD.

Stem cell therapy in inflammatory bowel disease: A promising therapeutic strategy?

Inflammatory bowel diseases are inflammatory, chronic and progressive diseases of the intestinal tract for which no curative treatment is available. Research in other fields with stem cells of different sources and with immunoregulatory cells (regulatory T-lymphocytes and dendritic T-cells) opens up new expectations for their use in these diseases. The goal for stem cell-based therapy is to provide a permanent cure. To achieve this, it will be necessary to obtain a cellular product, original or genetically modified, that has a high migration capacity and homes into the intestine, has high survival after transplantation, regulates the immune reaction while not being visible to the patient’s immune system, and repairs the injured tissue.

Stem cell therapy for inflammatory bowel disease

Inflammatory bowel disease (IBD) could be curable by "immune rest" and correction of the genetic predisposition inherent in allogeneic hematopoietic stem cell transplantation. However, balancing risks against benefits remains challenging. The application of mesenchymal stem cells (MSCs) serving as a site-regulated "drugstore" is a recent concept, which suggests the possibility of an alternative treatment for many intractable diseases such as IBD. Depending on the required function of MSC, such as a cell provider, immune moderator, and/or trophic resource, MSC therapy should be optimized to maximize its therapeutic benefit. Therapeutic effects do not always require full engraftment of MSCs. Therefore, optimization of pleiotropic gut trophic factors produced by MSCs, which favoring not only regulating immune responses but also promoting tissue repair, must directly enhance new drug discoveries for treatment of IBD. Stem cell biology holds great promise for a new era of cell-based therapy, sparking considerable interest among scientists, clinicians, and patients. However, the translational arm of stem cell science remains in a relatively primitive state. Although several clinical studies using MSCs have been initiated, early results suggest several inherent problems. In each study, optimization of MSC therapy appears to be the most urgent problem, and can be resolved only by scientifically unveiling the mechanisms of therapeutic action. In the present review, the authors outline how such information would facilitate the critical steps in the paradigm shift from basic research on stem cell biology to clinical practice of regenerative medicine for conquering IBD in the near future.

Hematopoietic stem and progenitor cells can be enriched by implanting biomaterial into spatium intermusculare

Hematopoietic stem and progenitor cells (HSPCs) have been used successfully to treat patients with cancer and disorders of the blood and immune systems. In this study, we tried to enrich HSPCs by implanting biomaterials into the spatium intermusculare of mice hind limbs. Gelatine sponges were implanted into the spatium intermusculare of mice and then retrieved after 12 days. The presence of HSPCs in the migrating cells (MCs) was detected by phenotypically probing with CD34⁺Sca-1⁺ and functionally confirming the presence of using colony-forming cell assay and assessing the long-term reconstitution ability. The frequency of CD34⁺, Sca-1⁺, and CD34⁺Sca-1⁺ cells and colony formation unit in the MCs was much higher than that in the bone marrow (BM). Moreover, transplanted MCs were able to home to BM, muscle, and spleen, which induced an efficient long-term hematopoietic reconstitution in vivo. In addition, HSPCs within the MCs originated from the BM. Furthermore, the administration of G-CSF greatly reduced the time of implantation, and increased the number of MCs and frequency of HSPCs in the MCs. These data provide compelling evidence that HSPCs can be enriched by implanting biomaterial into spatium intermusculare. Implantation of biomaterial may be seen as the first step to a proof of their applicability to clinical practice in enriching HSPCs.

Stem cell autograft and allograft in autoimmune diseases

Autoimmune diseases are characterized by an insufficiency of immune tolerance and, although treated with a number of useful drugs, may need more unconventional therapeutic strategies for their more severe presentations. Among such unconventional therapeutic approaches, stem cell autograft and allograft have been used, with the aim of stimulating disease remission by modifying the pathogenic mechanisms that induce anomalous responses against self-antigens. Autologous transplantation is performed with the purpose of retuning autoimmune cells, whereas allogeneic transplantation is performed with the purpose of replacing anomalous immune effectors and mediators. In this article, we comprehensively review up-to-date information on the autoimmune diseases for which the transplantation of stem cells is indicated.

Understanding host-adherent-invasive Escherichia coli interaction in Crohn's disease: opening up new therapeutic strategies

A trillion of microorganisms colonize the mammalian intestine. Most of them have coevolved with the host in a symbiotic relationship and some of them have developed strategies to promote their replication in the presence of competing microbiota. Recent evidence suggests that perturbation of the microbial community favors the emergence of opportunistic pathogens, in particular adherent-invasive Escherichia coli (AIEC) that can increase incidence and severity of gut inflammation in the context of Crohn's disease (CD). This review will report the importance of AIEC as triggers of intestinal inflammation, focusing on their impact on epithelial barrier function and stimulation of mucosal inflammation. Beyond manipulation of immune response, restoration of gut microbiota as a new treatment option for CD patients will be discussed.

Hematopoietic stem cell transplantation for non-malignant gastrointestinal diseases

Both, autologous and allogeneic hematopoietic stem cell transplantation (HSCT) can be used to cure or ameliorate a variety of malignant and non-malignant diseases. The rationale behind this strategy is based on the concept of immunoablation using high-dose chemotherapy, with subsequent regeneration of naive T-lymphocytes derived from reinfused hematopoietic progenitor cells. In addition, the use of HSCT allows for the administration of high-dose chemotherapy (whether or not combined with immunomodulating agents such as antithymocyte globulin) resulting in a prompt remission in therapy-refractory patients. This review gives an update of the major areas of successful uses of HSCT in non-malignant gastrointestinal disorders. A Medline search has been conducted and all relevant published data were analyzed. HSCT has been proved successful in treating refractory Crohn’s disease (CD). Patients with refractory celiac disease type II and a high risk of developing enteropathy associated T-cell lymphoma have shown promising improvement. Data concerning HSCT and mesenchymal SCT in end-stage chronic liver diseases are encouraging. In refractory autoimmune gastrointestinal diseases high-dose chemotherapy followed by HSCT seems feasible and safe and might result in long-term improvement of disease activity. Mesenchymal SCT for a selected group of CD is promising and may represent a significant therapeutic alternative in treating fistulas in CD.

Classical and recent advances in the treatment of inflammatory bowel diseases

Crohn's disease (CD) and ulcerative colitis (UC) are intestinal disorders that comprise the inflammatory bowel diseases (IBD). These disorders have a significant effect on the quality of life of affected patients and the increasing number of IBD cases worldwide is a growing concern. Because of the overall burden of IBD and its multifactorial etiology, efforts have been made to improve the medical management of these inflammatory conditions. The classical therapeutic strategies aim to control the exacerbated host immune response with aminosalicylates, antibiotics, corticosteroids, thiopurines, methotrexate and anti-tumor necrosis factor (TNF) biological agents. Although successful in the treatment of several CD or UC conditions, these drugs have limited effectiveness, and variable responses may culminate in unpredictable outcomes. The ideal therapy should reduce inflammation without inducing immunosuppression, and remains a challenge to health care personnel. Recently, a number of additional approaches to IBD therapy, such as new target molecules for biological agents and cellular therapy, have shown promising results. A deeper understanding of IBD pathogenesis and the availability of novel therapies are needed to improve therapeutic success. This review describes the overall key features of therapies currently employed in clinical practice as well as novel and future alternative IBD treatment methods.

An update on medical management on Crohn's disease

INTRODUCTION

The management of Crohn's disease (CD) is continuously evolving. New issues emerging from more recent studies could influence the decision-making process in clinical practice.

AREAS COVERED

The aim of this review article is to highlight critical issues on the management of CD, new evidence from clinical trials, long-term prospective studies and real life experience, beyond the current guidelines.

EXPERT OPINION

The role of mucosal healing in clinical practice is uncertain, clinical remission remains the primary end point. The timing for the definition of steroid-resistant CD should be considered between 2 and 4 weeks. Early treatment strategy with immunomodulators is effective for inducing remission but no controlled data are available regarding long-term outcome. Combination therapy (anti-TNFs agents and immunosuppressors) is more effective than single therapy but there is a lack of long-term data and an increased risk of malignancy. The effect of mesalazine, metronidazole and azathioprine in reducing postoperative recurrence is not clinically relevant; biologics are effective, but the duration of treatment is unknown. New drugs are under investigation in order to find exit strategy for patients who no longer respond to biologics. Combination therapy set on anti-TNF-α is until now the best option both to achieve fistula healing and avoid recurrence.

Autologous stem cell transplantation in severe treatment-resistant Crohn's disease: long-term follow-up of UK patients treated on compassionate basis

BACKGROUND

Although autologous stem cell transplantation (ASCT) may achieve disease control in severe treatment-resistant Crohn's disease (CD), relapse is frequent, and there is little information regarding long-term outcomes in terms of response to subsequent treatments and complications of ASCT.

DESIGN

Retrospective evaluation of UK patients treated on a compassionate basis from three UK tertiary centres.

METHODS

We summarize long-term outcomes of six previously unreported patients with severe treatment-resistant CD treated with ASCT according to international guidelines between 2003 and 2009. Median duration of CD before ASCT was 14 (7-22) years. Following stem cell mobilization, patients were treated with high-dose cyclophosphamide (200 mg/kg) and rabbit anti-thymocyte globulin (7.5 mg/kg) followed by ASCT.

RESULTS

All patients tolerated ASCT with routine toxicities and no treatment-related mortality and are alive at 50-123 months post-ASCT. Clinical and endoscopic remissions of CD were confirmed at 3 months post-ASCT in five patients, although median time to next treatment for inflammatory disease was 10 months (range: 3-16 months). Subsequently, disease control was achieved with previously ineffective and newer treatments, with surgery performed predominantly for pre-existing fibrotic strictures. Two patients became independent of home total parenteral nutrition (TPN). Reported late complications of ASCT included hypothyroidism and ovarian failure.

CONCLUSION

Long-term follow-up supports the safety and feasibility of ASCT as a means of achieving short-term control of severe CD whilst potentially re-sensitizing the disease to medical therapy and reducing requirements for surgery and TPN. Given the inevitability of relapse, pre-emptive salvage and/or maintenance treatments post-ASCT should be the focus of future trials.

[Successful autologous haematopoietic stem cell transplantation in severe, therapy-resistant childhood Crohn's disease. Report on the first case in Hungary]

The biological therapy of Crohn's disease, such as infliximab is a powerful approach in the therapy of inflammatory bowel diseases. However, in some patients with aggressive disease course, even a combined immunosuppressive therapy will not result in permanent remission. Hematopoietic stem cell transplantation has emerged as a new potential therapeutic tool for inflammatory bowel diseases. The authors report the case of a 15-year-old boy with severe Crohn's disease resistant to combined immunosuppressive therapy. After a 3-years course of unsuccessful conventional therapy including infliximab, autologous hematopoietic stem cell transplantation was performed which resulted in a complete remission. One year after transplantation the patient has relapsed, but he could be treated effectively with conventional therapy regiments. To the best of knowledge of the authors, this is the first report in Hungary presenting hematopoietic stem cell therapy in patient with severe Crohn's disease.

Treatment of Crohn's disease complicated with myelodysplastic syndrome via allogeneic hematopoietic stem cell transplantation: case report and literature review

Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract arising in individuals with genetic predisposing factors and abnormalities of the immune system. Myelodysplastic syndrome (MDS), an acquired clonal hematologic disorder, is characterized by peripheral blood cytopenia, dysplastic changes in several types of hematopoietic cells of the bone marrow and peripheral blood, and a high risk of transformation to acute leukemia. CD rarely occurs in combination with MDS, and MDS treatment with hematopoietic stem cell transplantation (HSCT) has not been frequently reported. We report the case of a 50-year-old Chinese male who presented with abdominal pain, diarrhea, and fatigue. CD was diagnosed by colonoscopy, imaging studies, and pathological examination. He was initially treated with mesalazine and prednisone and thereafter he presented with pancytopenia. MDS (RAEB-I) was diagnosed by bone marrow examination, and karyotyping revealed 47, XY, +8. The patient was treated with thalidomide, andriol, and decitabine. Allogeneic HSCT was performed with a human leukocyte antigen-matched sibling as the donor. The patient is currently well at 14 months after HSCT, without abdominal pain, diarrhea, or fatigue. HSCT may be a promising treatment option for patients with combined CD and MDS.

Therapy of inflammatory bowel disease: what to expect in the next decade

PURPOSE OF REVIEW

The increased understanding of the molecular mechanisms that are responsible for inflammatory bowel disease (IBD) has led to a wide range of potential therapeutic targets for this condition. Physicians treating individuals with Crohn's disease and ulcerative colitis have a growing armamentarium of options to choose from in managing these patients. This article aims to summarize the relevant literature in the area of emerging therapy in IBD.

RECENT FINDINGS

The widespread use of antitumor necrosis factor medications brought a landmark change in the treatment of IBD. More recently, several drugs have been shown to provide benefit in IBD in phase III studies by blocking other antiinflammatory pathways. The most likely new medications that will be available include vedolizumab for ulcerative colitis and ustekinumab for Crohn's disease, which target cellular adhesion and inflammatory cell signaling, respectively. Other promising drugs focus on blockade of Janus kinase, inhibition of various chemokines, and biologic therapy such as hematopoietic stem cell transplants and mesenchymal cell infusions.

SUMMARY

The growing understanding of the pathogenesis of IBD has led to new molecular targets for therapy. Over the next decade, the number of treatments available will grow, targeting cellular adhesion, protein regulation, inflammatory signal pathways, and immune tolerance.

Stem cells as potential targeted therapy for inflammatory bowel disease

The incidence and prevalence of inflammatory bowel disease is increasing in Western countries. Current therapies, ranging from anti-inflammatory drugs, immunosuppressive regimens to new biological therapies, remain inadequate. Advances in our understanding of the pathophysiological mechanisms underlying the pathogenetic disease process and the recent findings on the regenerative and immunoregulatory potential of stem cells open new opportunities in the therapy of inflammatory bowel disease. Therapeutic modalities, including hematopoietic stem cells, adult mesenchymal stem/stromal cells, and the recently identified amniotic origin stem cells, attracted much attention in the recent years. The current review highlights the recent pivotal findings for stem cell-based approaches to inflammatory bowel disease therapy.

Therapy with stem cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) affects a part of the young population and has a strong impact upon quality of life. The underlying etiology is not known, and the existing treatments are not curative. Furthermore, a significant percentage of patients are refractory to therapy. In recent years there have been great advances in our knowledge of stem cells and their therapeutic applications. In this context, autologous hematopoietic stem cell transplantation (HSCT) has been used in application to severe refractory Crohn's disease (CD), with encouraging results. Allogenic HSCT would correct the genetic defects of the immune system, but is currently not accepted for the treatment of IBD because of its considerable risks. Mesenchymal stem cells (MSCs) have immune regulatory and regenerative properties, and low immunogenicity (both autologous and allogenic MSCs). Based on these properties, MSCs have been used via the systemic route in IBD with promising results, though it is still too soon to draw firm conclusions. Their local administration in perianal CD is the field where most progress has been made in recent years, with encouraging results. The next few years will be decisive for defining the role of such therapy in the management of IBD.

A phase 2 study of allogeneic mesenchymal stromal cells for luminal Crohn's disease refractory to biologic therapy

BACKGROUND & AIMS

Transplantation of peripheral blood stem cells has been successful therapy for small numbers of patients with Crohn's disease (CD), but requires prior myeloconditioning. Mesenchymal stromal cells (MSCs) escape immune recognition, so myeloconditioning is not required before their administration. We investigated the efficacy of allogeneic MSCs in patients with luminal CD.

METHODS

Our phase 2, open-label, multicenter study included 16 patients (21-55 y old; 6 men) with infliximab- or adalimumab-refractory, endoscopically confirmed, active luminal CD (CD activity index [CDAI], >250). Subjects were given intravenous infusions of allogeneic MSCs (2 × 10(6) cells/kg body weight) weekly for 4 weeks. The primary end point was clinical response (decrease in CDAI >100 points) 42 days after the first MSC administration; secondary end points were clinical remission (CDAI, <150), endoscopic improvement (a CD endoscopic index of severity [CDEIS] value, <3 or a decrease by >5), quality of life, level of C-reactive protein, and safety.

RESULTS

Among the 15 patients who completed the study, the mean CDAI score was reduced from 370 (median, 327; range, 256-603) to 203 (median, 129) at day 42 (P < .0001). The mean CDAI scores decreased after each MSC infusion (370 before administration, 269 on day 7, 240 on day 14, 209 on day 21, 182 on day 28, and 203 on day 42). Twelve patients had a clinical response (80%; 95% confidence interval, 72%-88%; mean reduction in CDAI, 211; range 102-367), 8 had clinical remission (53%; range, 43%-64%; mean CDAI at day 42, 94; range, 44-130). Seven patients had endoscopic improvement (47%), for whom the mean CDEIS scores decreased from 21.5 (range, 3.3-33) to 11.0 (range, 0.3-18.5). One patient had a serious adverse event (2 dysplasia-associated lesions), but this probably was not caused by MSCs.

CONCLUSIONS

In a phase 2 study, administration of allogeneic MSCs reduced CDAI and CDEIS scores in patients with luminal CD refractory to biologic therapy. ClinicalTrials.gov number, NCT01090817.

Biological therapies for inflammatory bowel diseases

The inflammatory bowel diseases (IBDs) are a group of diseases characterized by chronic intestinal inflammation. Complex mechanisms underlying intestinal inflammation in IBD make it difficult to cure this disease. Pathological response to IBD involves both the adaptive and innate immune systems. Advances in the understanding of the immune mechanisms have resulted in the development of multiple monoclonal antibodies and small molecules that represent an alternative to the use of current therapies for patients with refractory IBD. This article systematically reviews the mechanisms of action, efficacy and safety of different biological therapies and discusses future directions for the treatment of IBD.