Browsing by Subject "VEGF"
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(University of HelsinkiHelsingin yliopistoHelsingfors universitet, 2008)Equine idiopathic focal eosinophilic enteritis (IFEE) is one form of inflammatory bowel disease. The main clinical signs include colic, weight loss, hypoalbuminemia, acute small intestinal obstruction and pain, occasionally tachycardia and diarrhoea. Macroscopic lesions consist of focal or multifocal erythematous, circumferential bands or circumscribed plaques on the serosal surface of the small intestine. Histological hallmark is a severe focal inflammatory cell infiltration, which is dominated by eosinophils and disrupts the tissue architecture of the small intestine. Neutrophils, haemorrage, necrosis, oedema and activated vascular endothelium represent components of an active inflammatory process, at the same time chronicity is observed as fibroplasia, mononuclear leukocytes and neovascularisation are present in the tissue. Recently it has been suggested that IFEE is a focally exacerbated form of diffuse eosinophilic enteritis (DEE). A wide range of cells in the intestine of horses with IFEE have been shown to express mRNA of eotaxin, which is the major cytokine to recruit eosinophils to the tissue. This study was planned to investigate other significant cytokines in IFEE by examing the expression of interleukin (IL)-4, IL-5, tumor necrosis factor- α (TNF-α), interferon-γ (IFN-γ), transforming growth factor-β (TGF-β) mRNA and vascular endothelial growth factor (VEGF). IL-5 is a major activator of eosinophil differentiation and growth, IL-4 stimulates T cells to differentiate to T helper 2 cells and IFN-γ and TNF-α are known to activate macrophages. TGF-β promotes tissue repair and VEGF induces the proliferation of vascular endothelial cells. IL-5, IFN-γ, TNF-α and TGF-β were successfully amplified by PCR from RNA of a horse with IFEE. IL-4 could not be detected. RNA- in situ hybridisation(ISH) was developed for IFN-γ and TGF-β. 16 IFEE cases, 2 DEE cases and 1 case without any gastrointestinal disorders as a healthy control were included in this study. Mucosal epithelium, lymphocytes, macrophages, fibroblasts, vascular endothelium, eosinophils and neurons of the IFEE cases exhibited positive signals in ISH for IFN-γ and TGF-β mRNA and immunohistochemistry for VEGF. Very similar pattern of positive signals was obtained in ISH of the DEE cases as the IFEE cases. The healthy control case expressed positive signals in epithelium, neurons and vascular endothelium in ISH for IFN-γ mRNA and epithelium and neurons in ISH for TGF-β mRNA.
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(2011)Angiogenesis, the formation of new blood vessels from preexisting vascular network, is an essential process during tumor development. Growing tumors secrete different growth factors that induce angiogenesis, of which vascular endothelial growth factor (VEGF) is predominant. Angiogenesis inhibitors act either by blocking the extracellular bindning of growth factor to its receptor by monoclonal antibodies or by blocking the intracellular signalling pathway by small-molecule agents. The small-molecule agent sunitinib is a multitargeted tyrosine kinase inhibitor that has antiangiogenic and antitumor activities due to the selective inhibition of several tyrosine kinase receptors. Sunitinib is approved for treatment of gastrointestinal stromal tumors, renal cell carcinoma and pancreatic neuroendocrine tumors. Known side effects are hypertension, cardiotoxicity and renal damage. These toxic effects are due to sunitinibs "off-target" toxicity, which occurs when a tyrosine kinase inhibitor causes adverse effects via inhibiton of a kinase not intended to be a target of the drug. For example inhibition by sunitinib of AMPK, a kinase that plays key roles in maintaining metabolic homeostasis in the heart, accounts in part for the toxicity seen in cardiomyocytes exposed to sunitinib. By achieving a better understandning of what causes the side effects it could be possible to develop treatments that reduce off-target effects. Caloric restriction is one nonpharmacological approach that has been shown to have beneficial effects on the heart partly by activating sirtuins. Sirtuins regulate a diverse array of cellular functions, including metabolism, gene transcription, cell division and cellular stress response. The aim for this study was to investigate whether caloric restriction improves sunitinib-induced cardiovascular toxicity and renal damage in rats, and to study activated cellular pathways. In this study 40 spontaneously hypertensive rats (SHR) and 10 normotensive Wistar-Kyoto (WKY) rats were used. They were divided into groups depending on treatment; I WKY control, II SHR control, III SHR + caloric restriction 70 %, IV SHR + sunitinib 3 mg/kg and V SHR sunitinib 3 mg/kg + caloric restriction 70 %. The follow-up period was eigth weeks. Blood pressure was messured weekly, metabolic cages were used week 4 and week 8 for urine samples, echocardiography was performed the last week and vascular response was studied at the end. The proteins Sirt1 and AMPK in heart were investigated by Western blot and the amount of the marker of macrofage ED1 in kidney by immunohistochemistry. Based on this study it was observed that the dose 3 mg/kg sunitinib was well tolerated in rats because it did not cause more extensive hypertension, worse hypertrophy or renal damage compared to untreated SHR groups. This study also showed that short-term caloric restriction has beneficial cardiovascular effects.
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