Recent advances in the management of Crohn's disease

Haematopoietic stem cell transplantation for severe autoimmune diseases in children: A review of current literature, registry activity and future directions on behalf of the autoimmune diseases and paediatric diseases working parties of the European Society for Blood and Marrow Transplantation

Although modern clinical management strategies have improved the outcome of paediatric patients with severe autoimmune and inflammatory diseases over recent decades, a proportion will experience ongoing or recurrent/relapsing disease activity despite multiple therapies often leading to irreversible organ damage, and compromised quality of life, growth/development and long-term survival. Autologous and allogeneic haematopoietic stem cell transplantation (HSCT) have been used successfully to induce disease control and often apparent cure of severe treatment-refractory autoimmune diseases (ADs) in children. However, transplant-related outcomes are disease-dependent and long-term outcome data are limited in respect to efficacy and safety. Moreover, balancing risks of HSCT against AD prognosis with continually evolving non-transplant options is challenging. This review appraises published literature on HSCT strategies and outcomes in individual paediatric ADs. We also provide a summary of the European Society for Blood and Marrow Transplantation (EBMT) Registry, where 343 HSCT procedures (176 autologous and 167 allogeneic) have been reported in 326 children (<18 years) for a range of AD indications. HSCT is a promising treatment modality, with potential long-term disease control or cure, but therapy-related morbidity and mortality need to be reduced. Further research is warranted to establish the position of HSCT in paediatric ADs via registries and prospective clinical studies to support evidence-based interspeciality guidelines and recommendations.

Engineered Probiotics for Detection and Treatment of Inflammatory Intestinal Diseases

Inflammatory intestinal diseases such as Crohn's disease and ulcerative colitis have seen an increase in their prevalence in developing countries throughout the current decade. These are caused by a combination of genetic and environmental factors, altered immune response, intestinal epithelium disruption and dysbiosis in the gut microbiome. Current therapies are mainly focused on treating symptoms and are often expensive and ineffective in the long term. Recently, there has been an increase in our understanding of the relevance of the gut microbiome and its impact on human health. Advances in the use of probiotics and synthetic biology have led to the development of intestinal biosensors, bacteria engineered to detect inflammation biomarkers, that work as diagnostic tools. Additionally, live biotherapeutics have been engineered as delivery vehicles to produce treatment in situ avoiding common complications and side effects of current therapies. These genetic constructs often express a therapeutic substance constitutively, but others could be regulated externally by specific substrates, making the production of their treatment more efficient. Additionally, certain probiotics detecting specific biomarkers in situ and responding by generating a therapeutic substance are beginning to be developed. While most studies are still in the laboratory stage, a few modified probiotics have been tested in humans. These advances indicate that live biotherapeutics could have great potential as new treatments for inflammatory intestinal diseases.

Lower extremity necrotizing fasciitis: A unique initial presentation of Crohn's disease

Crohn's disease is a disease of the bowel, typically presenting with diarrhea, weight loss, and abdominal pain. Complications such as abscesses, fistulas, and strictures may require surgical intervention. We would like to report a patient with Crohn's disease who presented for the first time with left lower extremity necrotizing fasciitis. There are very few reports of necrotizing fasciitis in Crohn's disease as the initial presentation.

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A patient with necrotizing fasciitis caused by an intraabdominal process.

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Fistulizing Crohn's disease first presented as necrotizing fasciitis.

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Hip disarticulation in a crohn's patient.

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.

Engineered E. coli that detect and respond to gut inflammation through nitric oxide sensing

Advances in synthetic biology now allow for the reprogramming of microorganisms to execute specific tasks. Here, we describe the development of an engineered strain of E. coli capable of sensing and responding to the presence of a mammalian inflammatory signal. The synthetic gene regulatory circuit is designed to permanently alter gene expression in response to the well characterized inflammatory signal nitric oxide. The detection of nitric oxide initiates the expression of a DNA recombinase, causing the permanent activation of a DNA switch. We demonstrate that E. coli containing this synthetic circuit respond to nitric oxide from both chemical and biological sources, with permanent DNA recombination occurring in the presence of nitric oxide donor compounds or inflamed mouse ileum explants. In the future, this synthetic genetic circuit will be optimized to allow E. coli to reliably detect and respond to inflammation in vivo.

Accuracy of imaging for predicting operative approach in Crohn's disease

Background

The aim of this study was to assess the accuracy of preoperative imaging in detecting the extent of disease and predicting the operative approach in patients with Crohn's disease.

Methods

Patients with Crohn's disease who were scheduled to undergo operation were evaluated before operation using computed tomography enteroclysis (CTE) and magnetic resonance enterography (MRE). Preoperative imaging findings were correlated with intraoperative and pathological findings to estimate the capabilities of preoperative imaging in detecting lesions due to Crohn's disease. The operative approach determined before surgery was compared with the procedure actually performed, which was based on intraoperative findings.

Results

Fifty-two patients with Crohn's disease were studied; 26 were evaluated before surgery with CTE and 26 with MRE. Eighty-nine lesions due to Crohn's disease were confirmed surgically (60 small bowel stenoses, 21 fistulas and 8 abscesses). CTE confirmed the presence of 38 of 41 lesions (sensitivity 93 per cent) and MRE 48 of 48 lesions (sensitivity 100 per cent); a correct estimation of the disease with an exact prediction of the operative approach was obtained in 49 (94 per cent) of 52 patients. Discrepant findings between preoperative imaging and operative findings were observed in three patients (6 per cent), who had CTE.

Conclusion

Preoperative imaging using CTE or MRE is highly accurate for assessing Crohn's disease lesions before operation, allowing correct prediction of the operative approach.

Certolizumab pegol for the treatment of Crohn's disease

Certolizumab pegol is a polyethylene glycolated FAb' fragment of a humanized anti-TNF-alpha monoclonal antibody. This pegylated molecule binds with circulating TNF-alpha and forms an inactive complex that is then eliminated from the body. The drug has been shown to be better than placebo in the treatment of Crohn's disease and maintaining a clinical response in adult patients with moderate-to-severe active disease who have had an inadequate response to conventional therapy, and the treatment of adults with moderately to severely active rheumatoid arthritis. Comparative trials with an active control group are lacking. The most common adverse reactions include abdominal pain, diarrhea, injection site reactions and infection. All necessary live and attenuated vaccines should be given prior to the initiation of certolizumab pegol therapy, patients should be evaluated for TB risk factors and tested for latent TB prior to initiating therapy, and the initiation of therapy should be avoided if the patient has an active infection. Concomitant use with anakinra is not recommended because of the increased risk of serious infections and neutropenia. Therapy should be discontinued if the patient develops a serious infection during therapy.

Dietary medium-chain triglycerides prevent chemically induced experimental colitis in rats

The effects of dietary medium-chain triglycerides (MCTs) on experimental colitis induced by 2,4,6-trinitrobenzene sulphonic acid (TNBS) were investigated in rats. Male Wistar rats were given an intracolonic injection of TNBS and were then fed liquid diets containing MCTs or corn oil (AIN93) as controls. Serum and tissue samples were collected 1 week after TNBS enema. The severity of colitis was evaluated pathologically, and tissue myeloperoxidase (MPO) activity was measured. Furthermore, messenger RNA (mRNA) and protein levels for inflammatory cytokines and a chemokine were assessed by reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. In another set of experiments, the protein expression of Toll-like receptor (TLR)-4 in the colon was measured 1 week after feeding of liquid diets. To investigate the effects of MCTs on macrophages, RAW246.7 macrophages were incubated with media containing albumin conjugated with MCT or linoleic acid, which is the major component of corn oil. Then, the production of tumor necrosis factor-alpha (TNF-alpha) was measured. Dietary MCTs blunted significantly the protein levels of TLR-4 in the colon. Furthermore, the expression of TLR-4 was significantly blunted in RAW264.7 cells incubated with MCTs compared with cells incubated with linoleic acid. Induction of interleukin 1beta (IL-1beta), TNF-alpha, and macrophage inflammatory protein-2 (MIP-2) in the colon was attenuated by dietary MCT. Furthermore, MPO activities in the colonic tissue were significantly blunted in animals fed the MCT diets compared with those fed the control diets. As a result, dietary MCTs improved chemically induced colitis significantly. MCTs most likely are useful for the therapy of inflammatory bowel disease as an anti-inflammatory immunomodulating nutrient.

Crohn disease and mycobacterial infection in children: an intriguing relationship

The relation between Crohn disease (CD) and mycobacterial infection is complex and intriguing. The 2 conditions share common immunopathogenic features, and the hypothesis that Mycobacterium avium subspecies paratuberculosis may cause CD is still under debate. Moreover, differential diagnosis between CD and intestinal tuberculosis (TB) may be challenging, especially in the growing proportion of children immigrating from countries with a high prevalence of TB. Thus, in Western countries, paediatricians who are involved in the diagnosis and management of children with CD are expected to face intestinal TB more frequently than in the past and should always consider the differential diagnosis between these 2 conditions. In addition, the use of biological agents in the treatment of CD, which may reactivate latent TB, requires the development of targeted diagnostic algorithms. Children with CD who are candidates for treatment with antitumour necrosis factor-alpha agents should be screened for latent or active TB and closely followed over time, also considering possible failure of antitubercular prophylaxis and the frequent uncharacteristic presentation of TB in children receiving antitumour necrosis factor-alpha agents. In the present review, the most recent literature findings on these topics are reported, focusing particularly on the paediatric age group.