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

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

[Fundamentals of the microbiome]. / Grundlagen des Mikrobioms.

Until the middle of the 20th century, clinical microbiology was limited to bacterial cultures enabling the detection of pathogenic microorganisms. Knowledge about the mutual relationship between humans and microorganisms has increased slowly. With the introduction of culture-independent analysis methods, comprehensive cataloging of the human microbiome was possible for the first time. Since then, compositional changes in relation to diseases have been studied. The goals of the Human Microbiome Project and MetaHIT include comparative studies of healthy and diseased individuals. Numerous libraries on time- and location-dependent changes of the microbiota composition in human diseases have been created. However, a mathematical correlation does not equal biological or medical relevance. Future research needs to validate the hypotheses generated in these studies in functional experiments and evaluate their true impact on clinical practice.

Autoimmunity in Crohn's Disease-A Putative Stratification Factor of the Clinical Phenotype.

Inflammation in inflammatory bowel diseases (IBD) has been linked to a loss of tolerance to self-antigens suggesting the existence of autoantibodies in specific disease phenotypes. However, the lack of clearly defined autoantigenic targets has slowed down research. Genome-wide association studies have identified an impressive number of immune-related susceptibility loci for IBD with no clearly discernible pattern among them. Growing evidence supports the hypothesis that innate immune responses to a low-diversity and impaired gut microbiota may be of key importance in initiating and perpetuating chronic inflammation in IBD. Increasing evidence suggests that reduced microbial diversity and microbial-mucosal epithelium interaction (including adhesion and clearance) are critically involved in IBD pathogenesis. Along these lines the discovery of autoantigenic targets in Crohn's disease (CD) has refocused research in IBD on the possible role of autoimmune responses. The identification of the major zymogen granule membrane glycoprotein 2 (GP2) as an autoantigen in CD patients and its proposed role in the sensing of the microbiota lends credence to this trend. Loss of tolerance to GP2 occurs in up to 40% of patients with CD. Corresponding autoantibodies appear to be associated with distinct disease courses (types or phenotypes) in CD. Here, we critically review autoantibodies in CD for their impact on clinical practice and future IBD research. The immunomodulatory role of GP2 in innate and adaptive intestinal immunity is also discussed.

Vedolizumab provides clinical benefit over 1 year in patients with active inflammatory bowel disease - a prospective multicenter observational study.

BACKGROUND: Vedolizumab, a monoclonal antibody targeting the α4ß7-integrin, is effective in inducing and maintaining clinical remission in Crohn's disease and ulcerative colitis according to randomised clinical trials. AIM: To determine the long-term effectiveness of vedolizumab in a real-world clinical setting. METHODS: This observational registry assessed the clinical outcome in patients treated with vedolizumab for clinically active Crohn's disease (n = 67) or ulcerative colitis (n = 60). Primary endpoint was clinical remission (HBI ≤ 4/pMayo ≤ 1) at week 54. Secondary endpoints included clinical response rates (HBI/pMayo score drop ≥3) and steroid-free clinical remission at weeks 30 and 54. RESULTS: Vedolizumab was stopped in 69/127 (56%) patients after a median time of 18 weeks (range 2-49) predominantly owing to lack or loss of response. Using nonresponder imputation analysis, clinical remission and steroid-free remission rates were 21% and 15% in Crohn's disease and 25% and 22% in ulcerative colitis, respectively. Lack of clinical remission was associated with prior treatment with anti-TNF or with steroids for more than 3 months in the last 6 months in ulcerative colitis. At week 14, the absence of remission in Crohn's disease or nonresponse in ulcerative colitis indicated a low likelihood of clinical remission at week 54 [2/31 (7%) in Crohn's disease, 4/41 (10%) in ulcerative colitis]. Accordingly, declining C-reactive protein in inflammatory bowel disease and/or lower faecal calprotectin in ulcerative colitis at week 14 predicted remission at week 54. CONCLUSION: Among patients who started vedolizumab for active inflammatory bowel disease, clinical remission rates are 21-25% after 54 weeks.

Ferric maltol therapy for iron deficiency anaemia in patients with inflammatory bowel disease: long-term extension data from a Phase 3 study.

BACKGROUND: Ferric maltol was effective and well-tolerated in iron deficiency anaemia patients with inflammatory bowel disease during a 12-week placebo-controlled trial. AIM: To perform a Phase 3 extension study evaluating long-term efficacy and safety with ferric maltol in inflammatory bowel disease patients in whom oral ferrous therapies had failed to correct iron deficiency anaemia. METHODS: After 12 weeks of randomised, double-blind treatment, patients with iron deficiency anaemia and mild-to-moderate ulcerative colitis or Crohn's disease received open-label ferric maltol 30 mg b.d. for 52 weeks. RESULTS: 111 patients completed randomised treatment and 97 entered the open-label ferric maltol extension. In patients randomised to ferric maltol ('continued'; n = 50), mean ± s.d. haemoglobin increased by 3.07 ± 1.46 g/dL between baseline and Week 64. In patients randomised to placebo ('switch'; n = 47), haemoglobin increased by 2.19 ± 1.61 g/dL. Normal haemoglobin was achieved in high proportions of both continued and switch patients (89% and 83% at Week 64, respectively). Serum ferritin increased from 8.9 µg/L (baseline) to 26.0 µg/L (Week 12) in ferric maltol-treated patients, and to 57.4 µg/L amongst all patients at Week 64. In total, 80% of patients reported ≥1 adverse event by Week 64. Adverse events considered related to ferric maltol were recorded in 27/111 (24%) patients: 8/18 discontinuations due to adverse events were treatment-related. One patient was withdrawn due to increased ulcerative colitis activity. CONCLUSIONS: Normal haemoglobin was observed in ≥80% of patients from weeks 20-64 of long-term ferric maltol treatment, with concomitant increases in iron storage parameters. Ferric maltol was well-tolerated throughout this 64-week study.

Vedolizumab induction therapy for inflammatory bowel disease in clinical practice--a nationwide consecutive German cohort study.

BACKGROUND: Vedolizumab (VDZ) is a humanised monoclonal IgG1 antibody targeting α4 ß7 integrin. AIM: To investigate the real-world efficacy of vedolizumab for the treatment of Crohn's disease (CD) and ulcerative colitis (UC). METHODS: A consecutive cohort of 212 adult IBD patients with active disease (HBI >7/partial Mayo >4) newly receiving VDZ was prospectively recruited from 7 academic and 17 community centres. The primary endpoint was clinical remission (CRM) (CD HBI ≤4, UC pMayo ≤1) in week 14. Secondary endpoints included steroid-free remission (SFCRM), clinical response (CRS) (HBI/pMayo score drop ≥3), vedolizumab impact on CRP, calprotectin and haemoglobin. RESULTS: Data of 97 CD (71.1% female, HBI 11) and 115 UC (42.6% female, pMayo 6) patients were analysed. Only 5.2% CD and 24.3% UC were anti-TNFα naïve. Most had extensive mucosal involvement (Montreal L3 69.1%/E3 53.9%). At week 14, 23.7% vs. 23.5% of CD vs. UC patients achieved CRM, 19.6% vs. 19.1% SFCRM and 60.8% vs. 57.4% CRS, respectively (all based on NRI). Week 14 CRM in CD was significantly associated with no history of extraintestinal manifestations (P = 0.019), no prior adalimumab use (P = 0.011), no hospitalisation in the past 12 months (P = 0.015) and low HBI score (P = 0.02) and in UC with active or previous smoking (P = 0.044/0.028) and no anti-TNFα (P = 0.023) use. Low HBI (P = 0.019) and no hospitalisation in the past 12 months (P = 0.01) predict CD CRM. The three most common AE were joint pain, acne and nasopharyngitis. CONCLUSION: Vedolizumab is effective in routine use.

Long-term Outcomes in Steroid-refractory Ulcerative Colitis Treated with Tacrolimus Alone or in Combination with Purine Analogues.

BACKGROUND AND AIMS: Tacrolimus is recommended for the treatment of steroid-refractory ulcerative colitis (UC). Concomitantly started purine analogues (PAs) are used for the maintenance of remission, though their therapeutic relevance remains uncertain. Here we studied the role of PAs in the long-term outcome of steroid-refractory UC after tacrolimus treatment. METHODS: In five centres, charts of tacrolimus-treated UC patients with a steroid-refractory moderate to severe course were reviewed. Long-term efficacy was determined by colectomy rates and clinical remission in cases of colectomy-free survival for 3 months. RESULTS: We identified 156 patients (median age 34 years) with a median Lichtiger score of 12 (4-17) and pancolitis (E3) in 65% (101). The Kaplan-Meier curve for colectomy-free survival after month 3 showed a benefit in the PA group (p = 0.02). In patients treated with PA clinical remission was achieved in 82% (65/79) vs 67% (39/58) in those not treated with PA (p = 0.02). Time to colectomy was 2 years (median, 0.7-5.8) in the PA group and 0.8 years (0.3-4.7) in the group not treated with PAs (p = 0.02). Time to relapse was 1.2 years (median, 0.3-6.2) in patients with PA treatment and 0.5 years (0.3-3.9) in those without PA treatment (p = 0.05). Overall, clinical remission was achieved in 67% (104/156) of patients. Colectomy was performed in 29% (45/156) 0.5 years (median, 0.04-5.79) after initiation of tacrolimus. Ten (6%) patients had to stop tacrolimus due to adverse events and two (without PA treatment) died. CONCLUSIONS: Our study supports the efficacy of tacrolimus in steroid-refractory UC. Purine analogues appear to be beneficial for the long-term outcome of these patients.

Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines.

The management of patients with IBD requires evaluation with objective tools, both at the time of diagnosis and throughout the course of the disease, to determine the location, extension, activity and severity of inflammatory lesions, as well as, the potential existence of complications. Whereas endoscopy is a well-established and uniformly performed diagnostic examination, the implementation of radiologic techniques for assessment of IBD is still heterogeneous; variations in technical aspects and the degrees of experience and preferences exist across countries in Europe. ECCO and ESGAR scientific societies jointly elaborated a consensus to establish standards for imaging in IBD using magnetic resonance imaging, computed tomography, ultrasonography, and including also other radiologic procedures such as conventional radiology or nuclear medicine examinations for different clinical situations that include general principles, upper GI tract, colon and rectum, perineum, liver and biliary tract, emergency situation, and the postoperative setting. The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas such as the comparison of diagnostic accuracy between different techniques, the value for therapeutic monitoring, and the prognostic implications of particular findings.

Aberrant plasmacytoid dendritic cell distribution and function in patients with Crohn's disease and ulcerative colitis.

Dendritic cell (DC) function is believed to be of critical importance for the pathogenesis of inflammatory bowel disease (IBD). To date, most research in animal models and the few human data available is restricted to myeloid DC, while plasmacytoid DC (pDC) capable of controlling both innate and adaptive immune responses have not yet been investigated systematically in human Crohn's disease (CD) or ulcerative colitis (UC). CD11c(-) , CD303(+) /CD304(+) and CD123(+) pDC from peripheral blood (n = 90), mucosal tissue (n = 28) or mesenteric lymph nodes (n = 40) (MLNs) of patients with UC and CD or controls were purified and cultured. Thereafter, pDC were enumerated, phenotyped and cytokine secretion measured by flow cytometry (FACS), immunohistochemistry and/or cytometric bead array, respectively. Interferon (IFN)-α secretion following cytosine phosphatidyl guanine (CpG) A oligodeoxynucleotide (ODN) 2216 (5'-GGGGGACGATCGTCGGGGGG-3') stimulation was assessed by enzyme-linked immunosorbent assay (ELISA). We found a significantly higher frequency of pDC in the inflamed colonic mucosa and MLN of IBD patients. Moreover, the fraction of CD40 and CD86 expressing cultured peripheral blood pDC was significantly higher in flaring UC and CD patients and their secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8 were increased significantly compared with controls. In contrast, the IFN-α secretion of peripheral blood pDC isolated from flaring IBD, particularly in UC patients, was reduced significantly compared with controls. Our data suggest an aberrant distribution and function of pDC in IBD, contrary to their generally implicated role as inducers of tolerance. We speculate that the impaired IFN-α secretion may relate to the hypothesized defect in innate immunity in IBD and could also impact upon the generation of regulatory T cells (T(reg) ).

Exaggerated inflammatory response of primary human myeloid dendritic cells to lipopolysaccharide in patients with inflammatory bowel disease.

Inflammatory bowel disease (IBD) results from a breakdown of tolerance towards the indigenous flora in genetically susceptible hosts. Failure of dendritic cells (DC) to interpret molecular microbial patterns appropriately when directing innate and adaptive immune responses is conceivable. Primary (conventional, non-monocyte generated) CD1c(+)CD11c(+)CD14(-)CD16(-)CD19(-) myeloid blood or mucosal dendritic cells (mDC) from 76 patients with Crohn's disease (CD) or ulcerative colitis (UC) in remission, during flare-ups (FU) and 76 healthy or non-IBD controls were analysed by fluorescence activated cell sorter (FACS) flow cytometry and real-time polymerase chain reaction. Cytokine secretion of freshly isolated, cultured and lipopolysaccharide (LPS)-stimulated highly purified mDC (purity >95%) was assessed using cytometric bead arrays (CBA). More cultured and stimulated circulating mDC express CD40 in IBD patients. Stimulated circulating mDC from IBD patients secrete significantly more tumour necrosis factor (TNF)-alpha and interleukin (IL)-8. Toll-like receptor (TLR)-4 expression by mDC was higher in remission and increased significantly in flaring UC and CD patients compared with remission (P < 0.05) and controls (P < 0.001). Fluorochrome-labelled LPS uptake by mDC was evaluated at different time-points over 24 h by measuring mean fluorescence intensity (MFI). Circulating mDC from IBD patients take up more LPS and the uptake begins earlier compared with controls (P < 0.05 in CD-FU and UC-FU at 24 h). The frequency of mucosal mDC (P < 0.05) and the number of CD40 expressing mucosal mDC is significantly greater in UC and CD compared with non-IBD controls (P < 0.001 versus P < 0.01, respectively). Our data suggest an aberrant LPS response of mDC in IBD patients, resulting in an inflammatory phenotype and possibly intestinal homing in acute flares.

Saccharomyces boulardii inhibits lipopolysaccharide-induced activation of human dendritic cells and T cell proliferation.

Saccharomyces boulardii (Sb) is a probiotic yeast preparation that has demonstrated efficacy in inflammatory and infectious disorders of the gastrointestinal tract in controlled clinical trials. Although patients clearly benefit from treatment with Sb, little is known on how Sb unfolds its anti-inflammatory properties in humans. Dendritic cells (DC) balance tolerance and immunity and are involved critically in the control of T cell activation. Thus, they are believed to have a pivotal role in the initiation and perpetuation of chronic inflammatory disorders, not only in the gut. We therefore decided to investigate if Sb modulates DC function. Culture of primary (native, non-monocyte-derived) human myeloid CD1c+CD11c+CD123(-) DC (mDC) in the presence of Sb culture supernatant (active component molecular weight < 3 kDa, as evaluated by membrane partition chromatography) reduced significantly expression of the co-stimulatory molecules CD40 and CD80 (P < 0.01) and the DC mobilization marker CC-chemokine receptor CCR7 (CD197) (P < 0.001) induced by the prototypical microbial antigen lipopolysaccharide (LPS). Moreover, secretion of key proinflammatory cytokines such as tumour necrosis factor-alpha and interleukin (IL)-6 were notably reduced, while the secretion of anti-inflammatory IL-10 increased. Finally, Sb supernatant inhibited the proliferation of naive T cells in a mixed lymphocyte reaction with mDC. In summary, our data suggest that Sb may exhibit part of its anti-inflammatory potential through modulation of DC phenotype, function and migration by inhibition of their immune response to bacterial microbial surrogate antigens such as LPS.

Heterozygosity for IL23R p.Arg381Gln confers a protective effect not only against Crohn's disease but also ulcerative colitis.

BACKGROUND: A recent study reported that a non-synonymous single nucleotide polymorphism (rs11209026, p.Arg381Gln) located in the IL23R gene is a protective marker for inflammatory bowel disease. AIM: To analyse the frequency of p.Arg381Gln in three independent European inflammatory bowel disease cohorts and to evaluate how this variant influences disease behaviour. METHODS: We assessed a European cohort of 919 inflammatory bowel disease patients and compared the IL23R p.Arg381Gln genotype frequency with 845 healthy controls. Inflammatory bowel disease patients originated from Germany [Crohn's disease (CD): n = 318; ulcerative colitis (UC): n = 178], Hungary (CD: n = 148; UC: n = 118) and the Netherlands (CD: n = 157). Ethnically matched controls were included. We performed subtyping analysis in respect to CARD15 alterations and clinical characteristics. RESULTS: The frequency of the glutamine allele of p.Arg381Gln was significantly lower in inflammatory bowel disease patients compared with controls in a pooled analysis of all three cohorts (P < 0.000001) as well as in the individual cohorts (Germany: P = 0.001, Hungary: P = 0.02 and the Netherlands: P = 0.0002). The p.Arg381Gln genotype distribution was similar between CD and UC. We did not observe either statistical interactions between p.Arg381Gln and CARD15 variants or any significant associations between p.Arg381Gln genotype and subphenotypes. CONCLUSIONS: The p.Arg381Gln IL23R variant confers a protective effect against both CD and UC, but does not determine disease phenotype.

Escherichia coli strain Nissle 1917 ameliorates experimental colitis via toll-like receptor 2- and toll-like receptor 4-dependent pathways.

Toll-like receptors (TLRs) are key components of the innate immune system that trigger antimicrobial host defense responses. The aim of the present study was to analyze the effects of probiotic Escherichia coli Nissle strain 1917 in experimental colitis induced in TLR-2 and TLR-4 knockout mice. Colitis was induced in wild-type (wt), TLR-2 knockout, and TLR-4 knockout mice via administration of 5% dextran sodium sulfate (DSS). Mice were treated with either 0.9% NaCl or 10(7) E. coli Nissle 1917 twice daily, followed by the determination of disease activity, mucosal damage, and cytokine secretion. wt and TLR-2 knockout mice exposed to DSS developed acute colitis, whereas TLR-4 knockout mice developed significantly less inflammation. In wt mice, but not TLR-2 or TLR-4 knockout mice, E. coli Nissle 1917 ameliorated colitis and decreased proinflammatory cytokine secretion. In TLR-2 knockout mice a selective reduction of gamma interferon secretion was observed after E. coli Nissle 1917 treatment. In TLR-4 knockout mice, cytokine secretion was almost undetectable and not modulated by E. coli Nissle 1917, indicating that TLR-4 knockout mice do not develop colitis similar to the wt mice. Coculture of E. coli Nissle 1917 and human T cells increased TLR-2 and TLR-4 protein expression in T cells and increased NF-kappaB activity via TLR-2 and TLR-4. In conclusion, our data provide evidence that E. coli Nissle 1917 ameliorates experimental induced colitis in mice via TLR-2- and TLR-4-dependent pathways.

Patients with active inflammatory bowel disease lack immature peripheral blood plasmacytoid and myeloid dendritic cells.

BACKGROUND: Breakdown of tolerance against the commensal microflora is believed to be a major factor in the pathogenesis of inflammatory bowel disease (IBD). Dendritic cells (DC) have been implicated in this process in various animal models, but data on human DC in IBD are very limited. AIM: To characterise plasmacytoid DC (PDC) and myeloid DC (MDC) in patients with active versus inactive IBD and healthy controls. PATIENTS AND METHODS: Peripheral blood was obtained from 106 patients (Crohn's disease (CD) n=49, ulcerative colitis (UC) n=57) and healthy controls (n=19). Disease activity was scored using the modified Truelove Witts (MTWSI) for UC and the Harvey Bradshaw severity indices (HBSI) for CD. Four colour flow cytometric analysis was used to identify, enumerate, and phenotype DC. DC from patients with acute flare ups and healthy controls were cultured and stimulated with CpG ODN 2006 or lipopolysaccharide (LPS). RESULTS: IBD patients in remission (PDC UC, 0.39%; CD, 0.35%; MDC-1 UC, 0.23%; CD, 0.22% of PBMC) have slightly lower numbers of circulating DC compared with healthy controls (PDC 0.41%, MDC-1 0.25% of PBMC). In acute flare ups IBD patients experience a significant drop of DC (PDC UC, 0.04%; CD, 0.11%; MDC-1 UC, 0.11%; CD, 0.14% of PBMC) that correlates with disease activity (correlation coefficients: PDC MTWSI, 0.93; HBSI, 0.79; MDC-1 MTWSI, 0.75; HBSI, 0.81). Moreover, both express alpha4beta7 integrin and display an immature phenotype. Freshly isolated PDC and MDC-1 from untreated flaring IBD patients express higher baseline levels of CD86 which increases further in culture and upon stimulation compared with healthy controls. CONCLUSION: IBD patients lack immature blood DC during flare ups which possibly migrate to the gut. An aberrant response to microbial surrogate stimuli suggests a disturbed interaction with commensals.

Review article: the aetiopathogenesis of inflammatory bowel disease--immunology and repair mechanisms.

Although the aetiopathogenesis of Crohn's disease and ulcerative colitis, remains unsolved, current evidence indicates that defective T-cell apoptosis and impairment of intestinal epithelial barrier function play important roles in the pathogenesis of both conditions. Without appropriate control of T-cell proliferation and death during an immune response, an inappropriate accumulation of T cells and subsequent intestinal inflammation may occur. Differences in T-cell responses between Crohn's disease and ulcerative colitis have been identified, with mucosal T-cell apoptosis being defective in Crohn's disease, but not in ulcerative colitis. Furthermore, cell cycling is considerably faster, with a vigorous clonal expansion, in Crohn's disease, whereas, in ulcerative colitis, T cells cycle normally, but have a remarkably reduced capacity to divide and expand. The elimination of excessive T cells therefore seems to be a reasonable approach to restore the gut to a physiological state or, at least, a controlled state of inflammation. The tumour necrosis factor-alpha blocker, infliximab, exerts its beneficial effects, at least in part, by the induction of apoptosis in lamina propria T cells and monocytes. In addition, repeated damage and injury of the intestinal surface is a hallmark of inflammatory bowel disease and may facilitate the entry of luminal antigens into the mammalian organism and the initiation and perpetuation of both nonspecific and specific immune responses. A better understanding of and enhancement of intestinal repair mechanisms may thus provide future approaches for the treatment of inflammatory bowel disease.