Sander van der Marel

Quality of web-based information on inflammatory bowel diseases.

Background: The Internet is the largest source of health information and is widely used by inflammatory bowel disease (IBD) patients. As information is largely unregulated, our objective was to evaluate the quality, readability, accuracy, and accessibility of the information concerning IBD available on the World Wide Web. Methods: The phrases “inflammatory bowel disease,” “Crohns disease,” and “Ulcerative Colitis” were entered separately as search terms into the 6 most commonly used search engines. Sites were categorized as institutional, pharmaceutical, nonpharmaceutical commercial sites, charitable, support, or alternative medicine. Websites were evaluated for content quality using the validated DISCERN rating instrument. Readability was graded by the Flesch Reading Ease and the Flesch‐Kincaid Grade Level score. Results: Of the 76 websites evaluated by DISCERN, 43% of the sites were rated as excellent to good and 57% as fair to poor. Alternative medicine sites scored significant lower (P > 0.05) than institutional, pharmaceutical, and nonpharmaceutical commercial sites. There was no relation between a rating score and the position of a website on the search engine ranking. The median Flesch Reading Ease Score was 41.65 (range, 2.6‐77.7) and 11.85 (range, 6.2‐21.1) for the Flesch‐Kincaid Grade Level. Conclusions: The quality of websites containing information on IBD varies widely. Most of the online material available is too difficult to comprehend for a substantial portion of the patient population, and good quality information may be beyond reach of the average information seeker. Inflamm Bowel Dis 2009

Neutralizing antibodies against adeno-associated viruses in inflammatory bowel disease patients: implications for gene therapy.

Background: Inflammatory bowel diseases (IBDs) are comprised of two major disorders: Crohns disease (CD) and ulcerative colitis (UC). No curative treatment options are available, but gene therapy may offer an alternative therapeutic approach. For this a safe and reliable vector is needed. The adeno‐associated viruses (AAV) have attracted considerable interest as gene therapy vectors. However, neutralizing antibodies (nAbs) made in response to wildtype AAV have been associated with a partial to complete block of transduction in case of reexposure. Therefore, and in order to define AAV vector candidates to treat IBD patients, we characterized preexisting humoral responses to AAV in this population. Methods: We measured circulating antibodies against AAV serotypes 1, 2, 3, 4, 5, 6, and 8 using a previously established virus neutralization assay. In all, 100 healthy donors and 200 IBD patients serum samples (101 CD and 99 UC) were analyzed. Results: A significant difference was detected in the prevalence of nAbs for AAV types 1, 5, 6, and 8 between the healthy donors and the patient population. Furthermore, various disease phenotypic characteristics correlated with the prevalence of nAbs to all the serotypes studied. Conclusions: Our study establishes a foundation for the development of an AAV‐based gene therapy approach as a novel treatment for IBD. Furthermore, we show a relationship between disease phenotype in IBD patients and the humoral immune response to AAV.

Mir‐142‐3p target sequences reduce transgene‐directed immunogenicity following intramuscular adeno‐associated virus 1 vector‐mediated gene delivery

Muscle represents an important tissue target for adeno‐associated virus (AAV) vector‐mediated gene transfer in muscular, metabolic or blood‐related genetic disorders. However, several studies have demonstrated the appearance of immune responses against the transgene product after intramuscular AAV vector delivery that resulted in a limited efficacy of the treatment. Use of microRNAs that are specifically expressed in antigen‐presenting cells (APCs) is a promising approach for avoiding those immune responses. Cellular mir‐142‐3p, which is APC‐specific, is able to repress the translation of its target cellular transcripts by binding to a specific target sequences.

Gene and cell therapy based treatment strategies for inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are a group of chronic inflammatory disorders most commonly affecting young adults. Currently available therapies can result in induction and maintenance of remission, but are not curative and have sometimes important side effects. Advances in basic research in IBD have provided new therapeutic opportunities to target the inflammatory process involved. Gene and cell therapy approaches are suitable to prevent inflammation in the gastrointestinal tract and show therefore potential in the treatment of IBD. In this review, we present the current progress in the field of both gene and cell therapy and future prospects in the context of IBD. Regarding gene therapy, we focus on viral vectors and their applications in preclinical models. The focus for cell therapy is on regulatory T lymphocytes and mesenchymal stromal cells, their potential for the treatment of IBD and the progress made in both preclinical models and clinical trials.

Adeno-associated virus mediated delivery of Tregitope 167 ameliorates experimental colitis

AIM To explore the anti-inflammatory potential of adeno-associated virus-mediated delivery of Tregitope 167 in an experimental colitis model. METHODS The trinitrobenzene sulfonate (TNBS) model of induced colitis was used in Balb/c mice. Subsequently after intravenous adeno-associated virus-mediated regulatory T-cell epitopes (Tregitope) delivery, acute colitis was initiated by intra-rectal administration of 1.5 mg TNBS in 40% ethanol followed by a second treatment with TNBS (0.75 mg in 20% ethanol) 8 d later. Control groups included mice not treated with TNBS (healthy control group) and mice treated by TNBS only (diseased group). At the time of sacrifice colon weight, the disease activity index and histology damage score were determined. Immunohistochemical staining of the colonic tissues was performed to asses the cellular infiltrate and the presence of transcription factor forkhead Box-P3 (Foxp3). Thymus, mesenteric lymph nodes, liver and spleen tissue were collected and the corresponding lymphocyte populations were further assessed by flow cytometry analysis for the expression of CD4+ T cell and regulatory T cell associated markers. RESULTS The Tregitope 167 treated mice gained an average of 4% over their initial body weight at the time of sacrifice. In contrast, the mice treated with TNBS alone (no Tregitope) developed colitis, and lost 4% of their initial body weight at the time of sacrifice (P < 0.01). The body weight increase that had been observed in the mice pre-treated with Tregitope 167 was substantiated by a lower disease activity index and a decreased colon weight as compared to the diseased control group (P < 0.01 and P < 0.001, respectively). Immunohistochemical staining of the colonic tissues for CD4+ showed that inflammatory cell infiltrates were present in TNBS treated mice with or without administration with tregitope 167 and that these cellular infiltrates consisted mainly of CD4+ cells. For both TNBS treated groups CD4+ T cell infiltrates were observed in the sub-epithelial layer and the lamina propria. CD4+ T cell infiltrates were also present in the muscularis mucosa layer of the diseased control mice, but were absent in the Tregitope 167 treated group. Numerous Foxp3 positive cells were detected in the lamina propria and sub-epithelium of the colon sections from mice treated with Tregitope 167. Furthermore, the Foxp3 and glycoprotein A repetitions predominant markers were significantly increased in the CD4+ T lymphocyte population in the thymus of the mice pre-treated with adeno-associated virus serotype 5 (cytomegalovirus promoter-Tregitope 167), as cytomegalovirus promoter compared to lymphocyte populations in the thymus of diseased and the healthy control mice (P < 0.05 and P < 0.001, respectively). CONCLUSION This study identifies adeno-associated virus-mediated delivery of regulatory T-cell epitope 167 as a novel anti-inflammatory approach with the capacity to decrease intestinal inflammation and induce long-term remission in inflammatory bowel disease.

Teaching tolerance: New approaches to enzyme replacement therapy for Pompe disease.

Babies born with Pompe disease require life-long treatment with enzyme-replacement therapy (ERT). Despite the human origin of the therapy, recombinant human lysosomal acid α glucosidase (GAA, rhGAA), ERT unfortunately leads to the development of high titers of anti-rhGAA antibody, decreased effectiveness of ERT, and a fatal outcome for a significant number of children who have Pompe disease. The severity of disease, anti-drug antibody (ADA) development, and the consequences thereof are directly related to the degree of the enzyme deficiency. Babies born with a complete deficiency GAA are said to have cross-reactive immunologic material (CRIM)–negative Pompe disease and are highly likely to develop GAA ADA. Less frequently, GAA ADA develop in CRIM-positive individuals. Currently, GAA-ADA sero-positive babies are treated with a combination of immunosuppressive drugs to induce immunological tolerance to ERT, but the long-term effect of these regimens is unknown. Alternative approaches that might redirect the immune response toward antigen-specific tolerance without immunosuppressive agents are needed. Methods leading to the induction of antigen-specific regulatory T cells (Tregs), using peptides such as Tregitopes (T regulatory cell epitopes) are under consideration for the future treatment of CRIM-negative Pompe disease. Tregitopes are natural T cell epitopes derived from immunoglobulin G (IgG) that cause the expansion and activation of regulatory T cells (Treg). Teaching the immune system to tolerate GAA by co-delivering GAA with Tregitope peptides might dramatically improve the lives of CRIM-negative babies and could be applied to other enzyme replacement therapies to which ADA have been induced.

Murine CD4+CD25- cells activated in vitro with PMA/ionomycin and anti-CD3 acquire regulatory function and ameliorate experimental colitis in vivo

BackgroundInduced regulatory T (iTreg) lymphocytes show promise for application in the treatment of allergic, autoimmune and inflammatory disorders. iTreg cells demonstrate advantages over natural Treg (nTreg) cells in terms of increased number of starting population and greater potential to proliferate. Different activation methods to generate iTreg cells result in iTreg cells that are heterogeneous in phenotype and mechanisms of suppression. Therefore it is of interest to explore new techniques to generate iTreg cells and to determine their physiological relevance.MethodsUsing phorbol myristate acetate (PMA)/ionomycin and anti-CD3 activation of CD4+CD25- cells we generated in vitro functional CD4+CD25+ iTreg (TregPMA) cells. Functionality of the generated TregPMA cells was tested in vivo in a mouse model of inflammatory bowel disease (IBD) - CD45RB transfer colitis model.ResultsTregPMA cells expressed regulatory markers and proved to ameliorate the disease phenotype in murine CD45RB transfer colitis model. The body weight loss and disease activity scores for TregPMA treated mice were reduced when compared to diseased control group. Histological assessment of colon sections confirmed amelioration of the disease phenotype. Additionally, cytokine analysis showed decreased levels of proinflammatory colonic and plasma IL-6, colonic IL-1 β and higher levels of colonic IL-17 when compared to diseased control group.ConclusionsThis study identifies a new method to generate in vitro iTreg cells (TregPMA cells) which physiological efficacy has been demonstrated in vivo.