Disturbances in microbiota - cause or effect?

IBD are a group of complex polygenetic diseases also involving environmental factors. Evidence for a role for bacteria in IBD include an increased abundance of mucosa-associated bacteria in IBD (which occurs even where there is no intestinal inflammation), and the positive impact of antibiotics on the progress of both Crohn's disease (CD) and ulcerative colitis (UC) of the pouch - pouchitis. Bacteria are necessary for most animal models of IBD. The increased abundance of mucosal bacteria in IBD is not non-specific because while some mucosal bacteria are more abundant this is not the case for all mucosal bacteria including the very abundant Bacteroides vulgatus. On the other hand, antibiotic treatments are not curative, and the humoral immune Ig response to bacterial antigens which is more evident in CD, appears to be polyclonal. While this argues against a role for specific bacteria causing a classical infection, certain mucosal bacteria may damage the mucosal barrier. This would promote invasion by other commensal mucosal bacteria triggering an immune response. Altered adaptive, and to a lesser extent, innate immunity have been extensively studied, and genetic defects in the CARD15 (or NOD2) gene that encodes a bacterial sensing protein modulating innate and adaptive immunity are strongly associated with ileal CD. However, the penetrance of the homozygous CARD15 frameshift mutation, which is the most strongly CD-associated genotype, is very low with only 4% of humans with this developing CD. Furthermore, mice with the same defects in CARD15 do not develop spontaneous ileitis or colitis. Therefore, there have to be other aetiological factor(s). Altered permeability is a consistent finding in subclinical CD. There are other data to suggest that altered mucin is an early event in UC. We propose that the pathogenesis of IBD is multifactorial involving specific mucosal bacteria, defective barrier function and altered mucosal immunity in an aetiology triangle.

Altered mucin expression in the gastrointestinal tract: a review

Early studies of changes in mucin expression in disorders of the gastrointestinal tract focused on alterations in the carbohydrate chain. This review briefly considers the various mechanisms by which such alterations may come about: (a) normal variation, (b) sialic acid alterations, (c) defective assembly of carbohydrate side-chains, (d) changed expression of core proteins and (e) epithelial metaplasia. The availability of monoclonal antibodies to mucin core proteins adds a new dimension to mucin histochemistry. It is now possible to offer explanations for traditional mucin histochemical findings on the basis of lineage-specific patterns of mucin core protein expression. Changes in core protein expression are described in inflammatory, metaplastic and neoplastic disorders of the gastrointestinal tract. The possibility that mucin change could be important in the aetiology of some diseases such as ulcerative colitis and H. pylori gastritis is considered. It is more probable, however, that changes in mucin expression are secondary to reprogramming of cellular differentiation and altered cell turnover. As such they may serve as markers to explain pathogenesis and provide novel diagnostic and prognostic information.

CD40 and CD86 upregulation with divergent CMRF44 expression on blood dendritic cells in inflammatory bowel diseases

OBJECTIVE: Dendritic cells (DC) are the only antigen-presenting cells that can activate naive T lymphocytes and initiate a primary immune response. They are also thought to have a role in immune tolerance. DC traffic from the blood to peripheral tissue where they become activated. They then present antigen and the costimulating signals necessary to initiate an immune response. In this study, we investigated the number, subsets, and activation pattern of circulating and intestinal DC from patients with clinically mild ulcerative colitis (UC) or Crohn's disease. METHODS: Patients were recruited, if they were not taking immunosuppressive therapy, and were assessed for clinical severity of their disease using for UC, the Clinical Activity Index, and for Crohn's disease, the Crohn's Disease Activity Index. Blood CD11c(+) and CD11c(-) DC subsets, expression of costimulatory antigens, CD86 and CD40, and the early differentiation/activation antigen, CMRF44, were enumerated by multicolor flow cytometry of lineage negative (lin(-) = CD3(-), CD19(-), CD14(-), CD16(-)) HLA-DR+ DC. These data were compared with age-matched healthy and the disease control groups of chronic noninflammatory GI diseases (cGI), acute noninflammatory GI diseases (aGI), and chronic non-GI inflammation (non-GI). In addition, cryostat sections of colonoscopic biopsies from healthy control patients and inflamed versus noninflamed gut mucosa of inflammatory bowel disease (IBD) patients were examined for CD86(+) and CD40(+)lin(-) cells. RESULTS: Twenty-one Crohn's disease and 25 UC patients, with mean Crohn's Disease Activity Index of 98 and Clinical Activity Index of 3.1, and 56 healthy controls, five cGI, five aGI, and six non-GI were studied. CD11c(+) and CD11c(-) DC subsets did not differ significantly between Crohn's, UC, and healthy control groups. Expression of CD86 and CD40 on freshly isolated blood DC from Crohn's patients appeared higher (16.6%, 31%) and was significantly higher in UC (26.6%, 46.3%) versus healthy controls (5.5%, 25%) (p = 0.004, p = 0.012) and non-GI controls (10.2%, 22.8%) (p = 0.012, p = 0.008), but not versus cGI or aGI controls. CD86(+) and CD40(+) DC were also present in inflamed colonic and ileal mucosa from UC and Crohn's patients but not in noninflamed IBD mucosa or normal mucosa. Expression of the CMRF44 antigen was low on freshly isolated DC, but it was upregulated after 24-h culture on DC from all groups, although significantly less so on DC from UC versus Crohn's or healthy controls (p = 0.024). The CMRF44(+) antigen was mainly associated with CD11c(+) DC, and in UC was inversely related to the Clinical Activity Index (r = -0.69, p = 0.0002). CONCLUSIONS: There is upregulation of costimulatory molecules on blood DC even in very mild IBD but surprisingly, there is divergent expression of the differentiation/activation CMRF44 antigen. Upregulation of costimulatory molecules and divergent expression of CMRF44 in blood DC was also apparent in cGI and aGI but not in non-GI or healthy controls, whereas intestinal CD86(+) and CD40(+) DC were found only in inflamed mucosa from IBD patients. Persistent or distorted activation of blood DC or divergent regulation of costimulatory and activation antigens may have important implications for gut mucosal immunity and inflammation. (Am J Gastroenterol 2001;96:2946-2956. (C) 2001 by Am. Coll. of Gastroenterology).

The histopathological approach to inflammatory bowel disease: a practice guide

Inflammatory bowel diseases (IBDs) are lifelong disorders predominantly present in developed countries. In their pathogenesis, an interaction between genetic and environmental factors is involved. This practice guide, prepared on behalf of the European Society of Pathology and the European Crohn's and Colitis Organisation, intends to provide a thorough basis for the histological evaluation of resection specimens and biopsy samples from patients with ulcerative colitis or Crohn's disease. Histopathologically, these diseases are characterised by the extent and the distribution of mucosal architectural abnormality, the cellularity of the lamina propria and the cell types present, but these features frequently overlap. If a definitive diagnosis is not possible, the term indeterminate colitis is used for resection specimens and the term inflammatory bowel disease unclassified for biopsies. Activity of disease is reflected by neutrophil granulocyte infiltration and epithelial damage. The evolution of the histological features that are useful for diagnosis is time- and disease-activity dependent: early disease and long-standing disease show different microscopic aspects. Likewise, the histopathology of childhood-onset IBD is distinctly different from adult-onset IBD. In the differential diagnosis of severe colitis refractory to immunosuppressive therapy, reactivation of latent cytomegalovirus (CMV) infection should be considered and CMV should be tested for in all patients. Finally, patients with longstanding IBD have an increased risk for the development of adenocarcinoma. Dysplasia is the universally used marker of an increased cancer risk, but inter-observer agreement is poor for the categories low-grade dysplasia and indefinite for dysplasia. A diagnosis of dysplasia should not be made by a single pathologist but needs to be confirmed by a pathologist with expertise in gastrointestinal pathology.

Modulation of inflammatory mediators by Opuntia ficus-indica and Prunus avium bioproducts using an in vitro cell-based model of intestinal inflammation

Dissertation to obtain a Master Degree in Biotechnology

Homogneous time resolved fluorescence: a new technique for detection and quantifications of infliximab in autoimmune patients

RESUMO:As terapias biológicas revolucionaram o tratamento das doenças autoimunes nos últimos anos. Tipicamente têm como alvos mediadores importantes no mecanismo das doenças. Os antagonistas do fator de necrose tumoral-α (TNF-α) são um grupo de agentes biológicos muito prescrito, pois estão indicados no tratamento de doenças imuno-mediadas comuns, tais como artrite reumatoide, artrite idiopática juvenil, artrite psoriática, espondilite anquilosante, doença de Crohn e colite ulcerosa. Com o uso frequente de inibidores do TNF-α, tem-se tornado evidente que estes agentes têm um potencial imunogénico importante, que pode comprometer o prognóstico a longo prazo dos doentes cronicamente tratados. A produção de anticorpos anti-fármaco parece causar falência terapêutica secundária em muitos doentes. Um dos efeitos dos anticorpos anti-fármaco é o aumento da eliminação do fármaco. A eliminação do fármaco, por sua vez, varia entre indivíduos, refletindo diferentes perfis farmacocinéticos. A determinação dos níveis séricos mínimos do agente anti-TNF-α é assim muito informativa e pode auxiliar nas decisões terapêuticas. Contudo, os testes imunológicos para determinar as concentrações séricas do fármaco não estão facilmente disponíveis na prática clínica. De forma a investigar uma nova técnica potencialmente fidedigna e prática para a deteção e quantificação dos agentes biológicos anti-TNF-α, foi testada a técnica por HTRF (homogeneous time-resolved fluorescence resonance energy transfer) para a determinação de concentrações séricas de infliximab. Apesar de apresentar algumas limitações relacionadas com as condições de leitura da fluorescência, esta técnica provou obter resultados próximos das concentrações obtidas por ELISA (enzyme-linked immunosorbent assay) bridging. Adicionalmente, tem a vantagem de ser de execução muito mais fácil e rápida. Deste modo, a técnica por HTRF poderá ser otimizada e tornar-se uma valiosa ferramenta laboratorial para orientar as decisões terapêuticas em doentes autoimunes com falência da terapêutica anti-TNF-α.--------- ABSTRACT: Biologic therapies revolutionized the treatment of autoimmune diseases in the last years. Typically, they target important disease mediators. Tumor necrosis factor-alpha (TNF-α) antagonists constitute a very prescribed group of biologic agents as they are indicated for the treatment of common immune-mediated diseases, such as rheumatoid arthritis, juvenile idiopathic arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn’s disease and ulcerative colitis. With the increasing use of TNF-α inhibitors it has been noticed that they have an important immunogenic potential that can compromise long-term outcomes in chronically treated patients. The production of anti-drug antibodies seems to cause secondary therapeutic failure in many patients. One of the effects of anti-drug antibodies is the enhancement of drug clearance. Drug clearance, in turn, varies among individuals, reflecting different pharmacokinetic profiles. Determination of serum anti-TNF-α drug trough levels is though very informative and could support treatment decisions. However, immunologic assays to determine drug serum concentrations are not readily available in clinical practice. In order to investigate a potentially reliable and practical new technique for detection and quantification of anti-TNF-α biologic agents, homogeneous time-resolved fluorescence resonance energy transfer (HTRF) technique was tested for determination of serum infliximab concentrations. Although presenting some limitations related with fluorescence reading conditions, this technique proved to give results close to the concentrations obtained by the widely used bridging enzyme-linked immunosorbent assay (ELISA). In addition, it has the advantage of being much easier and faster to perform. Thus, HTRF technique can be optimized and become a valuable laboratorial tool to guide treatment decisions in autoimmune patients with anti-TNF-α therapy failure.

Pelvic lymphoscintigraphy: contribution to the preoperative staging of rectal cancer

PURPOSE: Preservation of the anal sphincter in surgery for cancer of the distal rectum in an attempt to avoid colostomy has been a main concern of colorectal surgeons. Various proposed procedures contradict oncological principles, especially with respect to pelvic lymphadenectomy. Therefore, prior knowledge of pelvic lymph node involvement is an important factor in choosing the operative technique, i.e., radical or conservative resection. Introduction of ultrasound, computerized tomography, and magnetic resonance have made preoperative study of the area possible. Nevertheless, these resources offer information of an anatomical nature only. Lymphoscintigraphy enables the morphological and functional evaluation of the pelvic area and contributes toward complementing the data obtained with the other imaging techniques. The objective of this prospective study is twofold: to standardize the lymphoscintigraphy technique and to use it to differentiate patients with rectal cancer from those with other coloproctologic diseases. CASUISTIC AND METHODS: Sixty patients with various coloproctologic diseases were studied prospectively. Ages ranged from 21 to 96 years (average, 51 and median, 55 years). Twenty-six patients were male and 34 were female. Thirty patients had carcinoma of the distal rectum as diagnosed by proctologic and anatomic-pathologic examinations, 20 patients had hemorrhoids, 5 had chagasic megacolon, 2 had diverticular disease, 2 had neoplasm of the right colon, and 1 had ulcerative colitis as diagnosed by proctologic exam and/or enema. The lymphoscintigraphy method consisted of injecting 0.25 mL of a dextran solution marked with radioactive technetium-99m into the right and left sides of the perianal region and obtaining images with a gamma camera. The results were analyzed statistically with a confidence level of 95% (P < .05) using the following statistical techniques: arithmetic and medium average, Fisher exact test, chi-square test corrected for continuity according to Yates, and distribution tables for the number of patients. RESULTS: In rectal cancer, the tracer progresses unilaterally or is absent; in other patients, the progress of the tracer is bilateral and symmetrical, although its progress may be slow. Statistical tests showed with high significance that the agreement index between the clinical diagnosis and the result of the lymphoscintigraphic exam was 93%. CONCLUSIONS: Lymphoscintigraphy is a standardized, painless, and harmless test that can be performed in all cases; it differentiates patients with rectal cancer from those with other coloproctological diseases.

Inflammatory bowel diseases: principles of nutritional therapy

Inflammatory Bowel Diseases - ulcerative colitis and Crohn's disease- are chronic gastrointestinal inflammatory diseases of unknown etiology. Decreased oral intake, malabsorption, accelerated nutrient losses, increased requirements, and drug-nutrient interactions cause nutritional and functional deficiencies that require proper correction by nutritional therapy. The goals of the different forms of nutritional therapy are to correct nutritional disturbances and to modulate inflammatory response, thus influencing disease activity. Total parenteral nutrition has been used to correct and to prevent nutritional disturbances and to promote bowel rest during active disease, mainly in cases of digestive fistulae with high output. Its use should be reserved for patients who cannot tolerate enteral nutrition. Enteral nutrition is effective in inducing clinical remission in adults and promoting growth in children. Due to its low complication rate and lower costs, enteral nutrition should be preferred over total parenteral nutrition whenever possible. Both present equal effectiveness in primary therapy for remission of active Crohn's disease. Nutritional intervention may improve outcome in certain individuals; however, because of the costs and complications of such therapy, careful selection is warranted, especially in patients presumed to need total parenteral nutrition. Recent research has focused on the use of nutrients as primary treatment agents. Immunonutrition is an important therapeutic alternative in the management of inflammatory bowel diseases, modulating the inflammation and changing the eicosanoid synthesis profile. However, beneficial reported effects have yet to be translated into the clinical practice. The real efficacy of these and other nutrients (glutamine, short-chain fatty acids, antioxidants) still need further evaluation through prospective and randomized trials.

Prevalence and clinical importance of mesenteric venous thrombosis in the swiss inflammatory bowel disease cohort.

OBJECTIVE. The purpose of this study was to evaluate the prevalence of mesenteric venous thrombosis (MVT) in the Swiss Inflammatory Bowel Disease Cohort Study and to correlate MVT with clinical outcome. MATERIALS AND METHODS. Abdominal portal phase CT was used to examine patients with inflammatory bowel disease (IBD). Two experienced abdominal radiologists retrospectively analyzed the images, focusing on the superior and inferior mesenteric vein branches and looking for signs of acute or chronic thrombosis. The location of abnormalities was registered. The presence of MVT was correlated with IBD-related radiologic signs and complications. RESULTS. The cases of 160 patients with IBD (89 women, 71 men; Crohn disease [CD], 121 patients; ulcerative colitis [UC], 39 patients; median age at diagnosis, 27 years for patients with CD, 32 years for patients with UC) were analyzed. MVT was detected in 43 patients with IBD (26.8%). One of these patients had acute MVT; 38, chronic MVT; and four, both. The prevalence of MVT did not differ between CD (35/121 [28.9%]) and UC (8/39 [20.5%]) (p = 0.303). The location of thrombosis was different between CD and UC (CD, jejunal or ileal veins only [p = 0.005]; UC, rectocolic veins only [p = 0.001]). Almost all (41/43) cases of thrombosis were peripheral. MVT in CD patients was more frequently associated with bowel wall thickening (p = 0.013), mesenteric fat hypertrophy (p = 0.005), ascites (p = 0.002), and mesenteric lymph node enlargement (p = 0.036) and was associated with higher rate of bowel stenosis (p < 0.001) and more intestinal IBD-related surgery (p = 0.016) in the outcome. Statistical analyses for patients with UC were not relevant because of the limited population (n = 8). CONCLUSION. MVT is frequently found in patients with IBD. Among patients with CD, MVT is associated with bowel stenosis and CD-related intestinal surgery.

Periodontitis and gingivitis in inflammatory bowel disease: a case-control study.

BACKGROUND: The oral cavity is frequently affected in patients with inflammatory bowel disease (IBD), especially in patients with Crohn's disease (CD). Periodontitis is thought to influence systemic autoimmune or inflammatory diseases. We aimed to analyze the relationship of periodontitis and gingivitis markers with specific disease characteristics in patients with IBD and to compare these data with healthy controls. METHODS: In a prospective 8-month study, systematic oral examinations were performed in 113 patients with IBD, including 69 patients with CD and 44 patients with ulcerative colitis. For all patients, a structured personal history was taken. One hundred thirteen healthy volunteers served as a control group. Oral examination focussed on established oral health markers for periodontitis (bleeding on probing, loss of attachment, and periodontal pocket depth) and gingivitis (papilla bleeding index). Additionally, visible oral lesions were documented. RESULTS: Both gingivitis and periodontitis markers were higher in patients with IBD than in healthy control. In univariate analysis and logistic regression analysis, perianal disease was a risk factor for periodontitis. Nonsmoking decreased the risk of having periodontitis. No clear association was found between clinical activity and periodontitis in IBD. In only the CD subgroup, high clinical activity (Harvey-Bradshaw index > 10) was associated with 1 periodontitis marker, the loss of attachment at sites of maximal periodontal pocket depth. Oral lesions besides periodontitis and gingivitis were not common, but nevertheless observed in about 10% of patients with IBD. CONCLUSIONS: IBD, and especially perianal disease in CD, is associated with periodontitis. Optimal therapeutic strategies should probably focus on treating both local oral and systemic inflammation.

Predictors of temporary and permanent work disability in patients with inflammatory bowel disease: results of the swiss inflammatory bowel disease cohort study.

BACKGROUND: Inflammatory bowel disease can decrease the quality of life and induce work disability. We sought to (1) identify and quantify the predictors of disease-specific work disability in patients with inflammatory bowel disease and (2) assess the suitability of using cross-sectional data to predict future outcomes, using the Swiss Inflammatory Bowel Disease Cohort Study data. METHODS: A total of 1187 patients were enrolled and followed up for an average of 13 months. Predictors included patient and disease characteristics and drug utilization. Potential predictors were identified through an expert panel and published literature. We estimated adjusted effect estimates with 95% confidence intervals using logistic and zero-inflated Poisson regression. RESULTS: Overall, 699 (58.9%) experienced Crohn's disease and 488 (41.1%) had ulcerative colitis. Most important predictors for temporary work disability in patients with Crohn's disease included gender, disease duration, disease activity, C-reactive protein level, smoking, depressive symptoms, fistulas, extraintestinal manifestations, and the use of immunosuppressants/steroids. Temporary work disability in patients with ulcerative colitis was associated with age, disease duration, disease activity, and the use of steroids/antibiotics. In all patients, disease activity emerged as the only predictor of permanent work disability. Comparing data at enrollment versus follow-up yielded substantial differences regarding disability and predictors, with follow-up data showing greater predictor effects. CONCLUSIONS: We identified predictors of work disability in patients with Crohn's disease and ulcerative colitis. Our findings can help in forecasting these disease courses and guide the choice of appropriate measures to prevent adverse outcomes. Comparing cross-sectional and longitudinal data showed that the conduction of cohort studies is inevitable for the examination of disability.

Proteomic analysis of cytokine induced proteins in human intestinal epithelial cells: implications for inflammatory bowel diseases.

A role for cytokine regulated proteins in epithelial cells has been suggested in the pathogenesis of inflammatory bowel diseases (IBD). The aim of this study was to identify such cytokine regulated targets using a proteomic functional approach. Protein patterns from (35)S-radiolabeled homogenates of cultured colon epithelial cells were compared before and after exposure to interferon-gamma, interleukin-1beta and interleukin-6. Proteins were separated by two-dimensional polyacrylamide gel electrophoresis. Both autoradiographies and silver stained gels were analyzed. Proteins showing differential expression were identified by tryptic in-gel digestion and mass spectrometry. Metabolism related proteins were also investigated by Western blot analysis. Tryptophanyl-tRNA synthetase, indoleamine-2,3-dioxygenase, heterogeneous nuclear ribonucleoprotein JKTBP, interferon-induced 35kDa protein, proteasome subunit LMP2 and arginosuccinate synthetase were identified as cytokine modulated proteins in vitro. Using purified epithelial cells from patients, overexpression of indoleamine-2,3-dioxygenase, an enzyme involved in tryptophan metabolism, was confirmed in Crohn's disease as well as in ulcerative colitis, as compared to normal mucosa. No such difference was found in diverticulitis. Potentially, this observation opens new avenues in the treatment of IBD.

Prevalence and clinical importance of mesenteric venous thrombosis in the Swiss Inflammatory Bowel Disease Cohort

OBJECTIVE: The purpose of this study was to evaluate the prevalence of mesenteric venous thrombosis (MVT) in the Swiss Inflammatory Bowel Disease Cohort Study and to correlate MVT with clinical outcome. MATERIALS AND METHODS: Abdominal portal phase CT was used to examine patients with inflammatory bowel disease (IBD). Two experienced abdominal radiologists retrospectively analyzed the images, focusing on the superior and inferior mesenteric vein branches and looking for signs of acute or chronic thrombosis. The location of abnormalities was registered. The presence of MVT was correlated with IBD-related radiologic signs and complications. RESULTS: The cases of 160 patients with IBD (89 women, 71 men; Crohn disease [CD], 121 patients; ulcerative colitis [UC], 39 patients; median age at diagnosis, 27 years for patients with CD, 32 years for patients with UC) were analyzed. MVT was detected in 43 patients with IBD (26.8%). One of these patients had acute MVT; 38, chronic MVT; and four, both. The prevalence of MVT did not differ between CD (35/121 [28.9%]) and UC (8/39 [20.5%]) (p = 0.303). The location of thrombosis was different between CD and UC (CD, jejunal or ileal veins only [p = 0.005]; UC, rectocolic veins only [p = 0.001]). Almost all (41/43) cases of thrombosis were peripheral. MVT in CD patients was more frequently associated with bowel wall thickening (p = 0.013), mesenteric fat hypertrophy (p = 0.005), ascites (p = 0.002), and mesenteric lymph node enlargement (p = 0.036) and was associated with higher rate of bowel stenosis (p < 0.001) and more intestinal IBD-related surgery (p = 0.016) in the outcome. Statistical analyses for patients with UC were not relevant because of the limited population (n = 8). CONCLUSION: MVT is frequently found in patients with IBD. Among patients with CD, MVT is associated with bowel stenosis and CD-related intestinal surgery.