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Concentração sérica do fator de crescimento vascular endotelial - VEGF - e a profundidade da invasão trofoblástica na parede tubária em gestações ampulares / Serum concentration of the vascular endothelial growth factor - VEGF - and the depth of trophoblastic invasion into the tubal wall in ampular pregnanciesFabio Roberto Cabar 26 November 2008 (has links)
INTRODUÇÃO: A definição de fatores preditivos de lesão morfológica e funcional da tuba uterina poderia colaborar na escolha do tratamento de pacientes com gestação ectópica. O objetivo deste estudo foi relacionar a penetração do tecido trofoblástico na parede tubária acometida por gestação ampular com a concentração sérica materna de VEGF, avaliar a possibilidade do VEGF predizer a profundidade da invasão do tecido trofoblástico, comparando o desempenho do VEGF com o desempenho das concentrações séricas de beta-hCG na predição da profundidade da invasão do trofoblasto. MÉTODOS: realizou-se estudo prospectivo, entre 21 de dezembro de 2006 a 30 de setembro de 2007, com 30 pacientes com gestação tubária ampular submetidas à salpingectomia. Foram dosadas as concentrações séricas maternas de VEGF após confirmação do diagnóstico de gestação tubária e antes da realização da salpingectomia. Histologicamente a invasão trofoblástica na parede tubária foi classificada em grau I: quando limitada à mucosa da tuba uterina; grau II: até a camada muscular; grau III: invasão de toda a espessura da tuba uterina. RESULTADOS: 10 pacientes tiveram infiltração tubária grau I, 9 pacientes infiltração grau II e 11 pacientes infiltração grau III. Os diferentes graus de invasão trofoblástica apresentaram diferença significativa das concentrações séricas de VEGF (p< 0,001). O título sérico de VEGF de 305 pg/mL apresentou sensibilidade de 100,0%, especificidade de 85,0%, valor preditivo positivo de 76,9% e valor preditivo negativo de 100,0% para determinar invasão trofoblástica grau I. Título sérico de 425,9 pg/mL foi o melhor ponto de corte para predição de invasão trofoblástica grau III: sensibilidade de 81,8%, especificidade de 94,7%, valor preditivo positivo de 90,0% e valor preditivo negativo de 90,0%. Regressão logística selecionou a concentração sérica de VEGF como fator de melhor desempenho na predição da invasão trofoblástica quando comparado com título sérico de beta-hCG. CONCLUSÕES: em gestações ampulares, a profundidade da penetração do tecido trofoblástico na parede tubária acometida por gestação ectópica se relaciona com a concentração sérica de VEGF, a concentração sérica de VEGF é preditora da profundidade da invasão do tecido trofoblasto na parede tubária acometida por GE e a concentração sérica de VEGF apresenta melhor desempenho que a concentração sérica de beta-hCG como preditora da profundidade da invasão do trofoblasto na parede da tuba uterina acometida por gestação ampular / INTRODUCTION: The definition of predictive factors of morphologic and functional damage to the Fallopian tube may help in the choice of treatment for patients with ectopic pregnancy. The objective of the present study was to correlate the depth of penetration of trophoblastic tissue into the tubal wall with maternal serum VEGF concentrations, to evaluate the prediction of this invasion based on these concentrations and to compare the performances of VEGF and beta-hCG as predictors of trophoblastic invasion. METHODS: A prospective study was conducted on 30 patients with ampular pregnancy submitted to salpingectomy between December 21st, 2006 and September 30th, 2007. Maternal serum VEGF concentrations were measured after the diagnosis confirmation and before salpingectomy was performed. Histologically, trophoblastic invasion into the tubal wall was classified as grade I when limited to the tubal mucosa, grade II when reaching the muscle layer, and grade III when comprising the full thickness of the Fallopian tube. RESULTS: ten patients had tubal infiltration grade I, nine had grade II and eleven had grade III. The different levels of trophoblastic invasion were significantly associated with VEGF concentrations (p< 0.001). VEGF levels of 305.0 pg/mL showed 100.0% sensitivity, 85.0% specificity, a positive predictive value of 76.9% and a negative predictive value of 100.0% for the diagnosis of grade I trophoblastic invasion. A VEGF titer of 425.9 pg/mL was the best cut-off for the prediction of grade III trophoblastic invasion: 81.8% sensitivity, 94.7% specificity, positive predictive value of 90.0% and negative predictive value of 90.0%. Logistic regression showed that VEGF presented higher performance as a predictor of trophoblastic invasion than beta-hCG. CONCLUSIONS: in ampullary pregnancies, the depth of penetration of trophoblastic tissue into the tubal wall is correlated with serum VEGF concentrations, serum VEGF titer is predictor of the depth of penetration into tubal wall and VEGF concentrations present higher performance than beta-hCG as predictor of the trophoblastic invasion
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Avaliação dos níveis plasmáticos e urinários do fator de crescimento do endotélio vascular e dos níveis urinários das metaloproteinases 2 e 9 em pacientes com hemangioma infantil antes e durante o tratamento com betabloqueador sistêmico e tópico / Evaluation of plasma and urinary levels of endothelial growth factor and urinary levels of matrix metalloproteinases 2 and 9 in infantile hemangioma patients before and during systemic and topical ß-blocker treatmentRotter, Anita 27 November 2017 (has links)
INTRODUÇÃO: Fatores angiogênicos têm sido estudados em relação ao seu papel na patogênese do hemangioma da infância (HI). Durante o tratamento com betabloqueador, os pacientes com HI são acompanhados por exame físico e comparações por fotografia e ultrassonografia. Além disso, a dosagem sanguínea e urinária do fator de crescimento do endotélio vascular (VEGF) e a dosagem urinária das metaloproteinases 2 e 9 (MMP-2 e 9) podem ser ferramentas não invasivas para o acompanhamento evolutivo e terapêutico do HI. OBJETIVOS: Estudar os níveis de VEGF plasmático e urinário e MMP- 2 e MMP-9 urinárias em pacientes com HI, com o objetivo de avaliar sua possível relação na angiogênese do HI. MÉTODOS: foram incluídos 68 pacientes com hemangioma infantil e 25 controles, pareados por idade e sexo. Foi instituído tratamento sistêmico com propranolol em 45 crianças e tópico, com timolol, em 23. Os pacientes foram acompanhados por até 12 meses de tratamento com medidas de volume do HI pela ultrassonografia, dosagem plasmática e urinária de VEGF e dosagem urinária de MMP-2 e MMP-9 (ensaio Luminex). RESULTADOS: Os níveis de MMP-2 foram indetectáveis em mais de 50% das amostras. Antes do início do tratamento, não houve diferença dos níveis plasmáticos e urinários de VEGF e urinários de MMP-9 entre os grupos de pacientes com HI e controles. Não foi encontrada diferença significativa nos níveis plasmáticos e urinários dos biomarcadores de acordo com a fase de crescimento do hemangioma (crianças com 12 meses ou menos, em relação às maiores que 12 meses de idade). Não houve correlação entre o tamanho do HI e os níveis dos biomarcadores. Obteve-se correlação positiva significativa entre os níveis urinários de VEGF e MMP-9. No grupo tratado com propranolol, observou-se diminuição significativa do volume do HI com o tratamento, o que não foi verificado no grupo tratado com timolol. A variação dos valores dos biomarcadores obtidas antes, até seis meses e de sete a doze meses de tratamento, mostrou redução significativa de VEGF plasmático e MMP-9 urinária nas crianças tratadas com propranolol. Não foi observada variação significativa dos níveis dos biomarcadores durante o tratamento com timolol. CONCLUSÕES: os níveis plasmáticos e urinários de VEGF e os níveis urinários de MMP-9 não se mostraram bons marcadores de angiogênese aumentada nos pacientes com HI, nem tampouco refletiram o aumento da angiogênese característica da fase proliferativa do HI. No acompanhamento terapêutico dos HIs tratados com propranolol, a medida dos níveis dos biomarcadores mostrou diminuição significativa de VEGF plasmático e MMP-9 urinária, o que não foi observado com o timolol. A redução do volume do HI associada à diminuição dos biomarcadores nos pacientes tratados com propranolol sugeriu que o mecanismo de ação do betabloqueador nos HIs seja também por inibição da angiogênese. Desse modo, as dosagens de VEGF plasmático e MMP-9 urinária podem ser úteis para monitorar a efetividade do tratamento / INTRODUCTION: Angiogenic factors have been studied in regard to their role in the pathogenesis of infantile hemangioma (IH). During ß-blocker treatment, patients were monitored through physical examination and comparisons by photography and ultrasonography. In addition, plasma and urinary levels of vascular endothelial growth factor (VEGF) and urinary levels of matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) can be non-invasive tools to monitor the evolution of IH and its therapeutic follow-up. OBJECTIVES: To study plasma and urinary levels of VEGF and urinary levels of MMP-2 and MMP-9 in patients with IH, in order to evaluate their potential relation to the IH angiogenesis. METHODS: 68 IH patients and 25 controls were included, matched by age and gender. Systemic treatment with propranolol was administered to 45 patients, while topical timolol was administered to 23 patients. Patients were monitored for up to 12 months of treatment with measurements of IH volume through ultrasonography, plasma and urinary levels of VEGF and urinary levels of MMP-2 and MMP-9 (Luminex assays). RESULTS: MMP-2 levels were not detectable in over 50% of the samples. Before treatment, there was no difference in plasma and urinary levels of VEGF and urinary levels of MMP-9 between IH patients and control group. There was no significant difference in plasma and urinary levels for the biomarkers in accordance to the proliferative phase (12-month-old children or younger, in relation to children over 12 months of age). There was no correlation between IH size and biomarkers levels. There was a significant correlation between urinary levels of VEGF and MMP-9. In the propranolol group, a significant reduction of the IH volume with treatment was observed; this was not observed in the group treated with timolol. The variation of the biomarkers values obtained before, up to six months and from seven to twelve months of treatment indicated significant decrease in plasma levels of VEGF and urinary levels of MMP-9 in children treated with propranolol. It was not observed a significant variation of the biomarkers levels during timolol treatment. CONCLUSIONS: Plasma and urinary levels of VEGF and urinary levels of MMP-9 were not good markers of increased angiogenesis in patients with IH, nor reflected the increase in angiogenesis characteristic of the proliferative phase of IH. During therapeutic monitoring of IH treated with propranolol, a significant decrease in plasma VEGF and urinary MMP-9 levels was observed. The reduction in volume associated to the decrease in biomarkers in patients treated with propranolol suggested that its mechanism of action in IH occurs also through the inhibition of the angiogenesis. Thus, measurements of plasma levels of VEGF and urinary levels of MMP-9 may be useful to monitor the effectiveness of treatment
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Concentração sérica do fator de crescimento vascular endotelial - VEGF - e a profundidade da invasão trofoblástica na parede tubária em gestações ampulares / Serum concentration of the vascular endothelial growth factor - VEGF - and the depth of trophoblastic invasion into the tubal wall in ampular pregnanciesCabar, Fabio Roberto 26 November 2008 (has links)
INTRODUÇÃO: A definição de fatores preditivos de lesão morfológica e funcional da tuba uterina poderia colaborar na escolha do tratamento de pacientes com gestação ectópica. O objetivo deste estudo foi relacionar a penetração do tecido trofoblástico na parede tubária acometida por gestação ampular com a concentração sérica materna de VEGF, avaliar a possibilidade do VEGF predizer a profundidade da invasão do tecido trofoblástico, comparando o desempenho do VEGF com o desempenho das concentrações séricas de beta-hCG na predição da profundidade da invasão do trofoblasto. MÉTODOS: realizou-se estudo prospectivo, entre 21 de dezembro de 2006 a 30 de setembro de 2007, com 30 pacientes com gestação tubária ampular submetidas à salpingectomia. Foram dosadas as concentrações séricas maternas de VEGF após confirmação do diagnóstico de gestação tubária e antes da realização da salpingectomia. Histologicamente a invasão trofoblástica na parede tubária foi classificada em grau I: quando limitada à mucosa da tuba uterina; grau II: até a camada muscular; grau III: invasão de toda a espessura da tuba uterina. RESULTADOS: 10 pacientes tiveram infiltração tubária grau I, 9 pacientes infiltração grau II e 11 pacientes infiltração grau III. Os diferentes graus de invasão trofoblástica apresentaram diferença significativa das concentrações séricas de VEGF (p< 0,001). O título sérico de VEGF de 305 pg/mL apresentou sensibilidade de 100,0%, especificidade de 85,0%, valor preditivo positivo de 76,9% e valor preditivo negativo de 100,0% para determinar invasão trofoblástica grau I. Título sérico de 425,9 pg/mL foi o melhor ponto de corte para predição de invasão trofoblástica grau III: sensibilidade de 81,8%, especificidade de 94,7%, valor preditivo positivo de 90,0% e valor preditivo negativo de 90,0%. Regressão logística selecionou a concentração sérica de VEGF como fator de melhor desempenho na predição da invasão trofoblástica quando comparado com título sérico de beta-hCG. CONCLUSÕES: em gestações ampulares, a profundidade da penetração do tecido trofoblástico na parede tubária acometida por gestação ectópica se relaciona com a concentração sérica de VEGF, a concentração sérica de VEGF é preditora da profundidade da invasão do tecido trofoblasto na parede tubária acometida por GE e a concentração sérica de VEGF apresenta melhor desempenho que a concentração sérica de beta-hCG como preditora da profundidade da invasão do trofoblasto na parede da tuba uterina acometida por gestação ampular / INTRODUCTION: The definition of predictive factors of morphologic and functional damage to the Fallopian tube may help in the choice of treatment for patients with ectopic pregnancy. The objective of the present study was to correlate the depth of penetration of trophoblastic tissue into the tubal wall with maternal serum VEGF concentrations, to evaluate the prediction of this invasion based on these concentrations and to compare the performances of VEGF and beta-hCG as predictors of trophoblastic invasion. METHODS: A prospective study was conducted on 30 patients with ampular pregnancy submitted to salpingectomy between December 21st, 2006 and September 30th, 2007. Maternal serum VEGF concentrations were measured after the diagnosis confirmation and before salpingectomy was performed. Histologically, trophoblastic invasion into the tubal wall was classified as grade I when limited to the tubal mucosa, grade II when reaching the muscle layer, and grade III when comprising the full thickness of the Fallopian tube. RESULTS: ten patients had tubal infiltration grade I, nine had grade II and eleven had grade III. The different levels of trophoblastic invasion were significantly associated with VEGF concentrations (p< 0.001). VEGF levels of 305.0 pg/mL showed 100.0% sensitivity, 85.0% specificity, a positive predictive value of 76.9% and a negative predictive value of 100.0% for the diagnosis of grade I trophoblastic invasion. A VEGF titer of 425.9 pg/mL was the best cut-off for the prediction of grade III trophoblastic invasion: 81.8% sensitivity, 94.7% specificity, positive predictive value of 90.0% and negative predictive value of 90.0%. Logistic regression showed that VEGF presented higher performance as a predictor of trophoblastic invasion than beta-hCG. CONCLUSIONS: in ampullary pregnancies, the depth of penetration of trophoblastic tissue into the tubal wall is correlated with serum VEGF concentrations, serum VEGF titer is predictor of the depth of penetration into tubal wall and VEGF concentrations present higher performance than beta-hCG as predictor of the trophoblastic invasion
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Comparison of Neovascular Age-Related Macular Degeneration Populations in the United StatesCoultas, Susan Lynette 01 January 2016 (has links)
Age-related macular degeneration (AMD) is one of the leading causes of blindness in the United States in people who are 50 and older. The safety and efficacy of aflibercept for the treatment of late stage neovascular AMD (NAMD) has been demonstrated by clinical trials among several populations; however, it is unclear whether all NAMD patients respond in the same manner as was studied in the clinical trials. The purpose of this study was to examine if populations of patients treated with aflibercept for the treatment of NAMD were significantly different from one another in terms of health characteristics, treatment regimens, and treatment outcomes. The burden of treatment theory was used to guide this study. Data collected from electronic medical records were used to investigate NAMD characteristics 199 patients from 3 private, retinal practices in the United States. Data were analyzed using one-way ANOVA, 2, Spearman's correlation, and point-biserial correlation tests. The results of this study showed the specific retinal practice populations of NAMD patients treated with aflibercept were generally similar with respect to selected health characteristics, treatment regimens, and treatment outcomes. By using the information reported from this research, public health initiatives can be developed that focus on the need for early detection of AMD to capture changes that represent NAMD and move to early treatment for better outcomes. The positive social change that could result from this research is that retinal specialists may gain insight into the use and outcomes of aflibercept treatment.
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Heritable influences in oxygen-induced retinopathyvan Wijngaarden, Peter, petervanwijn@yahoo.com.au January 2006 (has links)
Retinopathy of prematurity, a disease characterised by aberrant retinal vascular development in premature neonates, is a leading cause of blindness and visual impairment in childhood. This work sought to examine differences in the susceptibility of inbred rat strains to oxygen-induced retinopathy, a model of human retinopathy of prematurity. The overriding aim was to identify genetic factors in rats that might be generalisable to humans.
Newborn rats of six different strains were exposed to alternating cycles of hyperoxia and relative hypoxia for fourteen days. Rats were removed to room air and killed for analysis immediately, to assess oxygen-induced retinal vascular attenuation, or four days later to evaluate the extent of hypoxia-induced vasoproliferation. Whole flat-mounted retinae were stained with fluorophore conjugated isolectin GS-IB4, and measurement of vascular area was conducted using fluorescence microscopy and video-image analysis. A hierarchy of susceptibility to the inhibitory effects of cyclic hyperoxia and relative hypoxia on postnatal retinal vascularization was identified for the rat strains studied. Susceptibility to vascular attenuation was predictive of the subsequent risk of vascular morphological abnormalities. Cross-breeding experiments between susceptible and resistant strains demonstrated that the susceptible phenotype was dominantly inherited in an autosomal fashion. These studies confirmed an association between ocular pigmentation and retinopathy risk, however the finding of differential susceptibility amongst albino rat strains implicated factors in addition to those associated with ocular pigmentation.
Quantitative real-time reverse transcription-polymerase chain reaction was used to compare the retinal expression of angiogenic factor genes in susceptible and resistant strains with the aim of identifying a genetic basis for the strain difference. Eight angiogenic factor genes were selected for study: vascular endothelial growth factor (VEGF); VEGF receptor 2; angiopoietin 2; Tie2; pigment epithelium-derived factor; erythropoietin; cyclooxygenase-2 and insulin-like growth factor-1. The most notable difference between strains was the expression of vascular endothelial growth factor (VEGF) during the cyclic hyperoxia exposure period - higher VEGF expression was associated with relative resistance to retinopathy. Other differences in retinal angiogenic factor gene expression between strains, such as higher expression of VEGF receptor 2 and angiopoietin 2 in resistant strains, appeared to be secondary to those in VEGF. Following cyclic hyperoxia, the expression pattern of angiogenic factor genes changed - messenger RNA levels of hypoxia-induced genes, including VEGF, VEGF receptor 2, angiopoietin 2 and erythropoietin, were significantly higher in those strains with larger avascular areas, than in those strains that were relatively resistant to retinopathy. These findings provide firm evidence for hereditary risk factors for oxygen-induced retinopathy in the rat. Differences in the regulatory effects of oxygen on VEGF expression appear to be central to the risk of retinopathy. The potential relevance of these hereditary factors is discussed in the context of the human disease.
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Collagenous Colitis : A Study of Inflammatory Mediators and Growth Factors Based on Segmental Colorectal Perfusion and ImmunohistochemistryTaha, Yesuf Ahmed January 2006 (has links)
<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>
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Collagenous Colitis : A Study of Inflammatory Mediators and Growth Factors Based on Segmental Colorectal Perfusion and ImmunohistochemistryTaha, Yesuf Ahmed January 2006 (has links)
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.
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A role for toll-like receptor-4 in pulmonary angiogenesis following multiple exposures to swine barn airJuneau, Vanessa Jade 14 June 2007
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.
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A role for toll-like receptor-4 in pulmonary angiogenesis following multiple exposures to swine barn airJuneau, Vanessa Jade 14 June 2007 (has links)
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.
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Emerging roles for the CD36 scavenger receptor in neovascular ocular diseaseMwaikambo, Bupe Rose. January 2008 (has links)
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.
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