<p>Collagenous colitis (CC) is an inflammatory bowel disease of unknown etiology. It is characterized by watery diarrhoea without blood, normal endoscopic findings but microscopically colonic mucosal inflammation and increased thickness of the subepithelial collagen band, the latter being a pathognomonic sign. The inflammatory infiltrate in the mucosa of CC contains lymphocytes, plasma cells, eosinophils, mast cells but few neutrophils. The pathophysiological roles of the thickened collagen band and the inflammatory infiltrate in CC are not fully understood. The aims of the present study were to develop a colonoscope based segmental perfusions technique and to analyze local intestinal secretion of inflammatory mediators: Eosinophilic Cationic Protein (ECP), Myeloperoxidase (MPO), Basic Fibroblast Growth Factor (bFGF), Vascular Endothelial Growth Factor (VEGF) and permeability marker albumin in CC patients without medication and also during steroid treatment. Furthermore, the colonic mucosal distribution of bFGF and VEGF were studied by immunohistochemical methods.</p><p>Colonoscope-based segmental perfusions were performed in totally 22 patients and the success rate was 76% in both rectal and descending colon segments. The analysis showed high intraluminal concentrations of ECP, bFGF, VEGF and albumin in ten CC patients compared to 10 control patients. Further, albumin had correlations with ECP and VEGF. However, elevated concentrations of MPO, an important feature of ulcerative colitis, were only observed in a few CC patients. Immunohistochemistry visualized bFGF and VEGF in the colonic epithelium but also deeper in the lamina propria. The steroid treatment study (including 12 patients) showed that the perfusate concentrations of ECP, bFGF and VEGF declined significantly in parallel with decreased frequency of diarrhoea. </p><p>In conclusion, a safe colonoscope-based, segmental perfusion technique was developed and perfusions of the rectum and descending colon were performed. CC patients had elevated perfusate concentrations of ECP, VEGF and bFGF. There was a marked reduction of these mediators during steroid treatment supporting the hypothesis that these inflammatory mediators separately or synergistically participate in the inflammatory reaction and tissue remodelling in CC patients. The finding of correlations between albumin and ECP or VEGF implies that permeability is increased in CC and may be triggered by ECP and VEGF. </p>

Collagenous colitis (CC) is an inflammatory bowel disease of unknown etiology. It is characterized by watery diarrhoea without blood, normal endoscopic findings but microscopically colonic mucosal inflammation and increased thickness of the subepithelial collagen band, the latter being a pathognomonic sign. The inflammatory infiltrate in the mucosa of CC contains lymphocytes, plasma cells, eosinophils, mast cells but few neutrophils. The pathophysiological roles of the thickened collagen band and the inflammatory infiltrate in CC are not fully understood. The aims of the present study were to develop a colonoscope based segmental perfusions technique and to analyze local intestinal secretion of inflammatory mediators: Eosinophilic Cationic Protein (ECP), Myeloperoxidase (MPO), Basic Fibroblast Growth Factor (bFGF), Vascular Endothelial Growth Factor (VEGF) and permeability marker albumin in CC patients without medication and also during steroid treatment. Furthermore, the colonic mucosal distribution of bFGF and VEGF were studied by immunohistochemical methods. Colonoscope-based segmental perfusions were performed in totally 22 patients and the success rate was 76% in both rectal and descending colon segments. The analysis showed high intraluminal concentrations of ECP, bFGF, VEGF and albumin in ten CC patients compared to 10 control patients. Further, albumin had correlations with ECP and VEGF. However, elevated concentrations of MPO, an important feature of ulcerative colitis, were only observed in a few CC patients. Immunohistochemistry visualized bFGF and VEGF in the colonic epithelium but also deeper in the lamina propria. The steroid treatment study (including 12 patients) showed that the perfusate concentrations of ECP, bFGF and VEGF declined significantly in parallel with decreased frequency of diarrhoea. In conclusion, a safe colonoscope-based, segmental perfusion technique was developed and perfusions of the rectum and descending colon were performed. CC patients had elevated perfusate concentrations of ECP, VEGF and bFGF. There was a marked reduction of these mediators during steroid treatment supporting the hypothesis that these inflammatory mediators separately or synergistically participate in the inflammatory reaction and tissue remodelling in CC patients. The finding of correlations between albumin and ECP or VEGF implies that permeability is increased in CC and may be triggered by ECP and VEGF.

Swine barn air is a heterogeneous mixture of dust, bacteria and irritant chemicals including ammonia and hydrogen sulphide. Gram-negative bacteria are commonly found in swine barn air and significantly contribute to pulmonary disease in unprotected swine barn workers, through the endotoxin moiety, lipopolysaccharide (LPS). Toll-like Receptor-4 is the ligand for LPS. It is found on many cell types including monocytes, macrophages, neutrophils, endothelial cells, and to a lesser extent, epithelial cells. The severity and outcome of acute lung injury following barn air exposures depends upon the balance between epithelial and vascular endothelial repair mechanisms, including angiogenesis. Vascular Endothelial Growth Factor (VEGF) is an endothelial mitogen produced by mesenchymal and alveolar Type II epithelial cells and by activated bronchial airway epithelial cells. Research investigating the role of cytokines in angiogenesis has shown that close proximity of immune cells and endothelial cells modulates the production of various compounds that regulate vascular function. Given that LPS is the ligand for TLR4 there appeared to be a role for TLR4 in angiogenesis, particularly following endotoxin exposure. To determine whether this was occurring, we examined whether exposure to swine barn air alters vascular density in the lungs and the role of TLR4 using a murine model. Toll-like Receptor-4 wild-type (C3HeB/FeJ) and TLR4 mutant (C3H/HeJ) mice were obtained and exposed to swine barn air for 1-, 5-, or 20-days for 8 hours/day. Wild-type animals showed a 127% increase in vascular density after 20-days barn air exposure. Vascular Endothelial Growth Factor-A protein levels were decreased by 0.62-fold after one-day swine barn air exposure in wild-type animals, indicating that VEGF-A is being used as a pro-angiogenic mitogen. Transcription of VEGF-A mRNA was increased in wild-type animals after all swine barn air exposure periods. The receptor VEGFR-1 showed increased mRNA transcription over all time points. These effects were only observed in TLR4 wild-type animals, indicating that these effects are mediated by TLR4. Further, VEGF-A and VEGFR-1 appear to be involved in the manifestation of TLR4-induced angiogenesis in the lung.

Swine barn air is a heterogeneous mixture of dust, bacteria and irritant chemicals including ammonia and hydrogen sulphide. Gram-negative bacteria are commonly found in swine barn air and significantly contribute to pulmonary disease in unprotected swine barn workers, through the endotoxin moiety, lipopolysaccharide (LPS). Toll-like Receptor-4 is the ligand for LPS. It is found on many cell types including monocytes, macrophages, neutrophils, endothelial cells, and to a lesser extent, epithelial cells. The severity and outcome of acute lung injury following barn air exposures depends upon the balance between epithelial and vascular endothelial repair mechanisms, including angiogenesis. Vascular Endothelial Growth Factor (VEGF) is an endothelial mitogen produced by mesenchymal and alveolar Type II epithelial cells and by activated bronchial airway epithelial cells. Research investigating the role of cytokines in angiogenesis has shown that close proximity of immune cells and endothelial cells modulates the production of various compounds that regulate vascular function. Given that LPS is the ligand for TLR4 there appeared to be a role for TLR4 in angiogenesis, particularly following endotoxin exposure. To determine whether this was occurring, we examined whether exposure to swine barn air alters vascular density in the lungs and the role of TLR4 using a murine model. Toll-like Receptor-4 wild-type (C3HeB/FeJ) and TLR4 mutant (C3H/HeJ) mice were obtained and exposed to swine barn air for 1-, 5-, or 20-days for 8 hours/day. Wild-type animals showed a 127% increase in vascular density after 20-days barn air exposure. Vascular Endothelial Growth Factor-A protein levels were decreased by 0.62-fold after one-day swine barn air exposure in wild-type animals, indicating that VEGF-A is being used as a pro-angiogenic mitogen. Transcription of VEGF-A mRNA was increased in wild-type animals after all swine barn air exposure periods. The receptor VEGFR-1 showed increased mRNA transcription over all time points. These effects were only observed in TLR4 wild-type animals, indicating that these effects are mediated by TLR4. Further, VEGF-A and VEGFR-1 appear to be involved in the manifestation of TLR4-induced angiogenesis in the lung.

Ocular neovascularization (NV) associated with corneal NV, ischemic retinopathies and age-related macular degeneration is a leading cause of severe vision loss. While numerous contributing factors have been identified, the potential role of the CD36 scavenger receptor has been largely overlooked notwithstanding its crucial involvement in normal retinal function. Accordingly, the central aim of this work was to elucidate the contribution and regulation of CD36 during ocular NV using the cornea as a model. / Initial work investigating the role of CD36 10 maintaining corneal avascularity, an important feature of the normal cornea, revealed that genetic ablation of CD36 elicits age-related corneal NV. Subsequent studies using a pathophysiologically relevant model of inflammatory corneal NV showed constitutive expression of CD36 in the normal cornea with marked induction in the neovascularized cornea. Importantly, activation of CD36 suppressed and induced regression of corneal NV, effects that proceeded via concerted inhibition of VEGFA, JNK-1, and cJun. / Because hypoxia is a fundamental stimulus for angiogenesis, it was pertinent to explore the role and regulation of CD36 during hypoxia. We demonstrate that CD36 expression was significantly elevated in hypoxia-exposed corneal and retinal tissue and in hypoxic retinal pigment epithelial cells. Essential contributions of hypoxia-inducible factor (HIF)-1 and reactive oxygen species were also established. Functional consequences were depicted by augmentations in CD36 phagocytic and anti-angiogenic activities. / Collectively, data disclose CD36 as an important modulator of corneal avascularity and inflammatory corneal NV; this imparts several interesting avenues for future research on the involvement of CD36 in neovascular diseases of the eye. Novel data further identify CD36 as a hypoxia and HIF-1 regulated gene thus creating a framework for future elucidation of the regulatory aspects of this receptor.

No description available.

Bien que l’environnement intra-utérin défavorable soit associé à des conditions pathologiques à l’âge adulte, les mécanismes mis en place in utero ne sont pas encore élucidés. Nous avons établi un modèle de restriction de croissance intra-utérine (RCIU) en donnant une diète faible en sodium à la rate pendant la dernière semaine de gestation. Ce modèle se caractérise par une diminution de perfusion placentaire et une redistribution du flot sanguin, favorisant l’irrigation des organes nobles (cœur et cerveau) au détriment du rein fœtal. De plus, l’expression rénale du facteur de croissance endothéliale vasculaire (VEGF) est diminuée chez le fœtus. L’hypothèse de travail est que la néoglucogenèse hépatique et rénale augmente chez les fœtus RCIU afin de compenser la diminution de perfusion placentaire, et que l’expression rénale des récepteurs de VEGF (Flt-1 et Flk-1) est altérée à la suite de la redistribution du flot sanguin. Nos objectifs étaient de comparer l’expression protéique des enzymes de la néoglucogenèse et des récepteurs de VEGF entre les fœtus témoins et RCIU. L’aldolase B, la fructose-1,6-biphosphatase et la glucose-6-phosphatase augmentent dans les reins de fœtus RCIU par rapport aux témoins alors qu’aucun changement n’est observé dans le foie. De plus, l’expression de ces enzymes est différente selon le sexe du fœtus. Une diminution de Flt-1 est notée dans les reins de fœtus RCIU. Nos résultats démontrent que des adaptations surviennent chez le fœtus à la suite d’une insulte intra-utérine favorisant sa survie mais ayant des conséquences telles que la dysfonction rénale observée chez les adultes de ce modèle animal. À long terme, ces travaux pourront permettre d’entrevoir des avenues pour mieux identifier les approches de prévention lors de naissance à la suite d’une RCIU. / An adverse intrauterine environment is associated with several pathological conditions at adult age, however, the mechanisms underlying such a link remain to be elucidated. Feeding a low-sodium diet to dams during the last week of gestation consistently resulted in giving birth to intrauterine growth restriction (IUGR) offsprings. The present model is characterized by a reduced placental perfusion and a redistribution of a preferential blood flow to the brain and heart at the expense of the kidney. Moreover, renal expression of the vascular endothelial growth factor (VEGF) is decreased in the IUGR fetuses. In this view, we hypothesize that the hepatic and renal gluconeogenesis is increased in the IUGR fetus in order to compensate the diminished placental perfusion, and the renal expression of VEGF receptors (Flt-1 and Flk-1) is altered in response to the redistribution of the blood flow. The specific aim of this study was to compare the protein expression of gluconeogenic enzymes and VEGF receptors between IUGR and control fetuses. Aldolase B, fructose-1,6- biphosphatase and glucose-6-phosphatase were significantly increased in the IUGR fetal kidneys compared to controls. However, gluconeogenic enzymes did not show any significant change in the IUGR liver. The fetal sex had an impact on the enzymes expression. A decreased expression of Flt-1 was also noted in the kidneys of the IUGR fetuses. Our results pointed out alterations in the fetal life that may be, in a way, essentiel for the survival of the fetus, but somehow, responsible for many pathological consequences at adult age, as the renal dysfunction observed in the present model. For the long term, this work may lead to many future perspectives helping to prevent several diseases, such as hypertension or diabetes for an IUGR case.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 117-139).

O lúpus eritematoso sistêmico (LES) é uma doença autoimune cuja fisiopatologia envolve mecanismos imunológicos, incluindo distúrbios nos processos de morte celular e nos mecanismos de eliminação de autoantígenos e de tolerância, acompanhados da formação de autoanticorpos patogênicos. Ele acomete principalmente mulheres jovens e a gestação nestas pacientes apresenta significativa morbimortalidade. Os achados clínicos e laboratoriais na nefrite lúpica são semelhantes àqueles encontrados em pacientes com pré-eclâmpsia (PE), especificamente hipertensão arterial, proteinúria e edema. Foi proposto o uso de fatores angiogênicos, como o fator de crescimento vascular endotelial (VEGF) e o fator de crescimento placentário (PlGF), e antiangiogênicos, como o receptor Fms-like tirosina quinase 1 solúvel (sFlt-1), para o diagnóstico diferencial entre estas duas condições, no entanto os dados disponíveis na literatura sobre estas citocinas em pacientes não gestantes com LES são inconsistentes. Este estudo foi desenhado para avaliar se existe diferença entre os níveis séricos de VEGF, PlGF e sFlt-1 em pacientes com LES com e sem atividade sistêmica da doença e se existe diferença nesses fatores quando comparamos pacientes com LES e mulheres saudáveis. Foram incluídas 54 mulheres com diagnóstico de LES em acompanhamento no ambulatório de Reumatologia do HUPE-UERJ, sem outra doença autoimune diagnosticada, e divididas de acordo com a atividade da doença. 30 pacientes tinham doença inativa (SLEDAI médio: 0,7) e 24 tinham doença ativa (SLEDAI médio: 11,6). 23 mulheres deste último grupo possuíam nefrite ativa, enquanto 20 das pacientes com doença em remissão já haviam apresentado nefrite ao longo da evolução do LES. O grupo controle foi formado por 34 mulheres hígidas atendidas no ambulatório de ginecologia da Policlínica Piquet Carneiro-UERJ. Considerando as três citocinas estudadas, as pacientes com LES apresentaram valores séricos médios superiores às mulheres do grupo controle (VEGF: 319,0 + 226,0 x 206,2 + 119,4, p=0,02; PlGF: 42,2 + 54,1 x 13,6 + 21,6, p=0,02; sFlt-1: 107,9 + 49,2 x 70,2 + 95,0, p=0,01). O grupo de pacientes com doença ativa também apresentou média superior ao controle nos três fatores (VEGF: 331,0 + 216,8 x 206,2 + 119,4, p=0,02; PlGF: 41,2 + 47,3 x 13,6 + 21,6, p=0,02; sFlt-1: 120,5 + 42,4 x 70,2 + 95,0, p=0,02), enquanto não foi encontrada diferença estatística entre o grupo de LES inativo e o controle. A média do sFlt-1 sérico foi maior nas pacientes com LES ativo do que a média das pacientes com a doença em remissão (120,5 + 54,9 x 97,8 + 42,4, p=0,02), mas não houve diferença significativa da média do VEGF e PlGF séricos entre os dois grupos. O melhor entendimento dos fatores angiogênicos e antiangiogênicos em pacientes com LES proporcionado por este estudo nos permite a análise dessas citocinas em gestantes com LES e, possivelmente, sua posterior aplicação como método diferencial entre nefrite lúpica e PE. / Systemic lupus erythematosus (SLE) is an autoimmune disease which pathophysiology involves immunological mechanisms including disturbances in the processes of cell death and mechanisms of elimination of autoantigens and tolerance, accompanied by formation of pathogenic autoantibodies. It mainly affects young women and pregnancy in these patients have significant morbidity and mortality. Clinical and laboratory findings in lupus nephritis are similar to those found in patients with preeclampsia (PE), specifically hypertension, proteinuria and edema. It has been proposed the use of angiogenic factors, such as vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), and antiangiogenic factors, as soluble Fms-like tyrosine kinase-1 (sFlt-1), for the differential diagnosis between these two conditions, however available data in the literature about these cytokines in non-pregnant SLE patients are inconsistent. This study was designed to evaluate whether there are differences between serum levels of VEGF, PlGF and sFlt-1 in SLE patients with and without systemic disease activity and whether there are differences in these factors when comparing SLE patients with healthy women. 54 women with SLE followed at outpatient clinic of Rheumatology HUPE - UERJ were included. They had no other autoimmune disease diagnosed and were divided according to disease activity. 30 patients had inactive disease (mean SLEDAI: 0.7), and 24 had active disease (mean SLEDAI: 11.6). 23 women in this latter group had active nephritis, while 20 patients with inactive disease had history of lupus nephritis. The control group consisted of 34 healthy women who attended the Gynecology outpatient clinic at Policlínica Piquet Carneiro - UERJ. Considering the three studied cytokines, the SLE patients had higher mean serum levels than the control group (VEGF: 319.0 + 226.0 x 206.2 + 119.4, p=0.02; PlGF: 42.2 + 54.1 x 13.6 + 21.6, p=0.02; sFlt-1: 107.9 + 49.2 x 70.2 + 95.0, p=0.01). The group of patients with active disease also had higher mean levels of all three factors than controls (VEGF: 331.0 + 216.8 x 206.2 + 119.4, p=0.02; PlGF: 41.2 + 47.3 x 13.6 + 21.6, p=0.02; sFlt-1: 120.5 + 42.4 x 70.2 + 95.0, p=0.02), whereas no statistical difference was found between the group with inactive SLE and the control group. The mean sFlt-1 levels were higher in patients with active SLE than the mean levels of patients with inactive disease (120.5 + 54.9 x 97.8 + 42.4, p=0.02), but there was no significant difference in mean serum of VEGF and PlGF levels between these two groups. A better understanding of angiogenic and antiangiogenic factors in patients with SLE provided by this study allows the analysis of these cytokines in pregnant woman with SLE and possibly their subsequent application as differential method between PE and lupus nephritis.