published_or_final_version / Pathology / Master / Master of Medical Sciences

No description available.

Thesis (Ph. D.)--University of Louisville, 2004. / Department of Physiology and Biophysics. Vita. "May 2004." Includes bibliographical references (leaves 173-182).

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Introduction; The inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), affect well over 100,000 people in the United Kingdom Health related quality of life (HRQOL) is influenced by many factors in IBD including; the nature and severity of the disease, socio-economic factors, age, psychological well-being as well as· the efficacy and complications of treatment. Pilot Studies; Quality of life was assessed in 140 IBD patients (70 CD/70 UC). Diarrhoea was, not surprisingly, the most commonly reported physical symptom in both CD and UC and impaired faecal continence caused great social disability, with 72% CD patients and 68% UC patients reporting urgency or incontinence. Over a third of all patients reported occupational problems associated with their disease. Anxiety, but not depression, was common in the CD group and a major source of anxiety in many cases was lack of information. Three-quarters of patients felt additional information would have enabled them to cope with their chronic illness. It is a common perception that the provision of psychological support, such as the use of counselling skills, may alleviate many of the psychosocial problems associated with IBD, but this has not yet been proven. Hypothesis: That a nurse led counselling service improves HRQOL in IB D patients. Study Group/Design: Fifty patients with CD (aged 16-64, 33 females), 50 UC patients (aged 17-60, 26 females), 50 healthy volunteers (HV, aged 17- 61, 27 females) and a disease control group comprising 28 psoriatic arthritis (PS) patients (aged 22-66, 16 females) undeiwent structured interviews and completed a range of questionnaires measuring several facets of quality of life and psychological well-being (Hospital Anxiety and Depression Score (HAD), Attitudes and Preferences (AP), Styles and Strategies (SS) and Short-form 36 (SF36)). Patients with IBD were then randomised to receive either a counselling package or routine clinical follow-up. The counselling package consisted of disease specific information and teaching of stress management techniques, based on the "Challenge to change" programme devised by Dr. Derek Roger at the University of York. HRQOL scores were compared on entry at 6 and 12 months. Results; At baseline the scores for all questionnaires were within the nonnal range in the UC, PS, and HV groups. However CD patients recorded significantly higher anxiety scores (p<O.O I) and demonstrated significantly higher maladaptive coping mechanism scores (p<0.05). At six months, the anxiety scores of the CD patients improved significantly (p<0.05) as did their maladaptive coping mechanism scores (P<0.05). There was no significant change in disease activity over this period. These improvements were maintained at twelve months. Summary/Conclusion; Psychological morbidity is common in CD and can be quantified using validated questionnaires. Psychological morbidity improves with basic psychological support and information provision but sophisticated stress management techniques are probably unnecessary.

published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 156-186).

L’étiologie et le développement des maladies inflammatoires chroniques de l’intestin (MICI), dont la maladie de Crohn (MC) et rectocolite hémorragique (RCH), sont encore mal compris. Il s’agit de maladies multifactorielles caractérisées par une dérégulation de la réponse immunitaire des muqueuses chez des individus génétiquement prédisposés, sous l’influence de facteurs environnementaux. À ce jour, seuls le tabagisme et l’appendicectomie sont décrits comme capables d’influencer le développement des MICI. Le rôle du tabac est ambivalent : il protège de la RCH mais aggrave le risque d’apparition de la MC. Néanmoins, malgré une littérature relativement abondante, il est à l’heure actuelle impossible d’assigner définitivement des propriétés immunomodulatrices particulières au tabac. De plus, aucun des modes d’actions du tabac proposés n’explique l’ambivalence observée entre la MC et la RCH. L’hypothèse la plus probable est celle d’un effet du tabac différent sur le côlon et l’intestin grêle.Partant de ces observations cliniques, ce travail a pour but de caractériser un (ou plusieurs) des mécanismes impliqués dans le rôle immunomodulateur du tabac d’une part au niveau du côlon et d’autre part au niveau de l’iléon, afin de réaliser une analyse différentielle sur ces deux organes.Deux modèles d’étude ont été mis en place sur des souris C57Bl/6. Les souris sont pré-exposées pendant 2 semaines à la fumée de cigarette via un protocole standardisé qui permet de mimer au mieux le tabagisme humain. Lors de la troisième semaine, l’inflammation est provoquée soit au niveau du côlon (traitement au DSS (Dextran Sodium Sulfate)), soit au niveau du grêle (traitement à l’indométacine). Chez les souris sauvages, l’exposition à la fumée de cigarette réduit significativement l’expression clinique de la colite et diminue l’expression des cytokines pro-inflammatoires Th1/Th17 dans le côlon. Cette protection est spécifique au côlon : aucune différence n’a pu être observée sur les paramètres cliniques de l’inflammation dans le modèle d’iléite.L’analyse des populations cellulaires met en évidence une augmentation de la proportion de lymphocytes iNKT au niveau du foie et du côlon (mais pas au niveau du grêle) des souris exposées. Ces cellules sont indispensables à l’effet protecteur lié à la fumée de cigarette au niveau du colon. En effet, la protection contre la colite au DSS liée à la fumée est abolie chez des souris déficientes en cellules NKT fonctionnelles. Par contre, dans le modèle d’iléite à l’indométacine, les souris déficientes en NKT montrent une sensible diminution de l’inflammation iléale lorsqu’elles sont exposées à la fumée de cigarette.Ces résultats semblent indiquer que les cellules iNKT joueraient un rôle différent en fonction de leur localisation dans le tractus intestinale, ou que des sous-populations différentes de cellules iNKT seraient impliquées dans le contrôle immunitaire dans le côlon et l’intestin grêle.Ce travail démontre clairement que, expérimentalement, la fumée de cigarette protège les souris de la colite mais pas de l’iléite. Pour la première fois, les cellules iNKT ont été identifiées comme ayant un rôle majeur dans la protection du côlon liée à la fumée de cigarette, tout en jouant potentiellement un rôle différent au niveau de l’iléon.Cette thèse apporte des données nouvelles et originales dans le domaine de la régulation de l’inflammation intestinale notamment par la fumée de cigarette, un facteur environnemental largement répandu. En outre, cibler les cellules iNKT pourrait constituer un nouveau moyen de contrôle de l’inflammation intestinale. La conception de nouvelles molécules agissant sur la polarisation des cellules iNKT pourrait faire l’objet d’une nouvelle voie thérapeutique visant à diminuer l’inflammation colique, en particulier au cours de la RCH. / Current hypothesis on the pathogenesis of inflammatory Bowel disease suggests that the disease development implicates a deregulated dialogue between the intestinal flora and components of both the innate and adaptive immune systems in genetically susceptible individuals and under the influence of environmental factors. To dateonly cigarette smoking and appendectomy have been shown to play a significant role. The effect of smoking appears to be ambivalent: it protects from ulcerative colitis (UC) but worsens Crohn’s disease (CD). Moreover, in CD it has been proposed that smoking might influence the disease location: CD patients who smoke were found to have a higher frequency of ileal disease and a lower frequency of colonic involvement. However, the molecular basis of the opposite effect of smoking in CD and UC still remain unexplained. Tobacco smoke molecules seem to possess various immunomodulatory properties but currently no clear conclusion can be drawn from in vitro and in vivo studies. To date, the influence of cigarette smoke on immune cells profile in the intestine remains unknown. The aim of this project was to characterize the effect of CS in murine models of intestinal inflammation, and the underlying mechanism implied in impact of CS in the colon and in the ileum at the cellular and molecular levels. To address this question, we developed a new model of exposition to CS using InExpose® exposure system (Scireq Inc) which allows us to accurately reproduce human smoking habits. We applied this protocol of exposure in two different animal models of intestinal inflammation: 1) the commonly used model of dextran sodium sulphate (DSS)-induced colitis and 2) the indomethacin-induced jejuno-ileitis model. C57BL/6 mice were pre-exposed to CS during two weeks before induction of one or another model of intestinal inflammationFirstly, we demonstrated in WT mice that CS exposure improved DSS-induced colitis but not indomethacin-induced ileitis. The colonic improvement was associated with a decrease in Th1/Th17 proinflammatory cytokines expression in the colon. This protection linked to CS exposure was specific to the colon since no modification of clinical and inflammatory parameters were observed in the jejuno-ileitis model.Secondly, we analyzed leukocyte population under CS exposure condition compared to control un-exposed mice. We showed by flow cytometry analysis that, in particular, iNKT cells were recruited by cigarette smoke in the colon and the liver (but not the small bowel) after CS exposure in non-inflammatory condition. To access the role of iNKT cells in CS dependant colonic protection, mice deficient in NKT cells (CD1dKO and J18KO mice) were exposed to the same protocols than WT mice. In NKT cell-deficient mice, CS exposure failed to improve colitis and to decrease the expression of proinflammatory cytokines. This implies that iNKT cells may be a major actor in the CS-dependent protection against DSS colitis. On the other hand, in NKT cell-deficient mice CS exposure seems to improve indomethacin-induced ileitis. This result indicates that iNKT cells could act differently according intestinal location or that the populations of iNKT in the different compartment of intestinal tracts may differ.In conclusion, this study demonstrated that mainstream CS exposure protects mice from experimental colitis but not from experimental ileitis. For the first time, we have identified iNKT cells as major player of the CS-dependent protection in colonic inflammation, whereas they might have a different role in the ileum. Therefore, our study contributes to better elucidate the impact of smoking, as a widespread environmental factor in IBD. Targeting iNKT cells would represent a novel therapeutic way. Design of new molecules acting on iNKT cells polarization could reproduce the effects of CS and allow decreasing the inflammation in the colon.

No description available.

The inflammatory bowel diseases (IBD), encompassing Crohn’s disease (CD) and ulcerative colitis (UC), are chronic inflammatory disorders of the gastrointestinal tract. Their aetiology is not fully understood but is thought to be a combination of the effect of environmental factors in a genetically susceptible person. The work presented is an examination of the phenotypic characteristics of CD in the Scottish population, and an investigation into genetic factors that may influence susceptibility and progression. An IBD cohort from Dundee was recruited (CD=367, UC=265), and extensive phenotypic information collected from these patients together with genomic DNA. Together with the Edinburgh CD cohort already established, the total CD population (n=1155) was examined for time to disease progression (stricturing and/or penetrating disease, according to the Montreal classification) and first resection; a multivariate analysis was performed for factors influencing these outcomes. In this Scottish CD population, the median time to disease progression and first resection was 14.2 years and 8.9 years respectively. The major factor influencing risk of resection and disease progression was disease location, with patients having pure ileal (L1) disease or ileocolonic (L3) disease being more susceptible than those with pure colonic (L2) disease. Compared with L2 disease, the hazards ratios (HR) for disease progression were 4.7 and 2.8, and risk of resection 5.2 and 2.6 for L1 and L3 disease respectively. Disease progression and risk of resection are surrogate markers of disease severity. To try to better understand the determinants of severe disease, a novel score for disease severity was developed and applied to the Dundee CD cohort. This composite score encompassed the variables of medical and surgical management, disease behaviour and location, nutritional status as well as hospitalisations, with a total score that could range from 1 to 16. A score of 7 or more was found to define the 50% of patients with the most severe disease. This cut-off was used to divide patients into less severe and more severe categories; phenotypic and genetic factors were examined for correlation with more severe disease. Genetic factors examined were the 32 most significant CD susceptibility single nucleotide polymorphisms (SNPs) uncovered by recent genome-wide association scans (GWAS). Factors correlated with more severe disease included disease location (L1, odds ratio (OR) 2.20, p=0.0025), age group at diagnosis (p=0.0004) and two CD susceptibility SNPs (rs9286879 and rs17582416; p=0.0085 and p=0.045 respectively). NOD2 was the first IBD susceptibility gene identified. In order to further define pathways involving NOD2, a yeast two-hybrid screen in our laboratory using NOD2 cDNA as the bait had already identified an interaction between NOD2 and UDP-Nacetyl- alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GALNT2). This enzyme is involved in O-glycosylation, important in the post translational modification of mucins. A GALNT2 genotype/phenotype analysis on the Edinburgh IBD population was completed, with the Dundee IBD population used as a replication cohort. In the Edinburgh IBD population, the GALNT2 tagging SNP rs7536663 was associated with CD susceptibility (OR 1.38, p=0.0008 vs controls), but replication was not achieved in the Dundee cohort (p=0.469). There was no association of any of the GALNT2 SNPs with UC. The GALNT2/NOD2 interaction was further investigated by completing coimmunoprecipitation between the two genes to characterise the level and type of interaction. An interaction between GALNT2 and NOD2 was confirmed in mammalian cells, with the interaction being at the N-terminal end of the NOD2 protein. GALNT2 expression in a cell line and biopsies was investigated by quantitative polymerase chain reaction and immunohistochemistry respectively. There were no statistically significant changes in GALNT2 or NOD2 mRNA expression in the LS174T cell line after stimulation with specific ligands for NOD2 and GALNT2. GALNT2 protein expression was characterised in intestinal biopsy samples to be predominantly in the lamina propria, with some expression in the enterocytes. To further define the contribution of mucin genes to IBD susceptibility, tagging SNPs across the MUC2, MUC3A and MUC19 genes were genotyped in the Edinburgh IBD cohort and examined for a link with IBD, CD and UC susceptibility, but associations were not found. In view of the strong association with CD susceptibility of a SNP near the MUC19 locus in a recent GWAS, tagging SNPs across the leucine rich repeat kinase-2 (LRRK2) gene, near the MUC19 gene, were also genotyped and examined in the Dundee cohort for an association with IBD, CD and UC susceptibility, but was also negative when corrected for multiple testing. The studies presented allow an improved understanding of the influence of phenotypic characteristics on disease progression, need for surgery and severity in CD. The role of disease location has been determined to be particularly critical, in keeping with other published studies. A detailed examination of the influence of specific genes on disease susceptibility has failed to definitely demonstrate an association between germline variation in GALNT2, MUC2, MUC3A, MUC19 or LRRK2 and IBD, CD or UC susceptibility. An interaction in mammalian cells between NOD2 and GALNT2 has been shown, but further work is required to demonstrate that this is a biologically relevant interaction.