| 研究概要 |
From previous several studies of our and other research groups, now we know vascular endothelial growth factor (VEGF) and its signaling cascade play a key central role in pathogenesis of multiple organ dysfunction syndromes in sepsis (MODS) of both animals and humans. Last year, we examined several drugs in sepsis animals to check whether the aberrant expression of VEGF in several important organs can be reversed and normalized in context of dose and time dependent manners. VEGF is significantly downregulated in sepsis animals in lung tissues and plays an important role in the pathogenesis of lung injury in sepsis. Blockade of protease activated receptor-2 normalized the downregulated pulmonary VEGF expression in sepsis rat models at early time points. In addition, the blockade of TNF-alpha in septic rats for three hours also significantly reversed the decreased pulmonary VEGF expression. These results establish a link between coagulation/fibrinolytic pathways with inflammatory mediators in the pathogenesis of lung injury in sepsis in context to the aberrant pulmonary VEGF expression. Like lung tissues, in septic heart at early hours, we also found decreased level of VEGF expression with altered hemodynamics. Treatment with landiolol, a selective ultra short acting beta blocker for three hours significantly reversed the decreased VEGF expression in heart tissues in sepsis. Thus, we state that TNF-alpha, protease activated receptor-2 and beta adrenergic receptors may have roles in regulating the expression of VEGF in heart and lung tissues at early hours of sepsis.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
The current research is on right track both from the contexts of time line and the amount of research activities scheduled to be done (100% done with target milestone achievement). Last year, we used five types of pharmacological drug interventions (protease activated receptor blockade-2, TNF-alpha blockade, landiolol hydrochloride treatment, dual endothelin blockade, recombinant VEGF therapy) in sepsis animals at various time points with various doses and systematically checking the effects of those drug treatments on VEGF expression in important sepsis-induced organ dysfunction (lung, heart, kidney, liver, brains). We investigated in depth both protein and gene expression of target molecules to be assessed in the present study with respective organ function and morphology. We also generated ARDS models by saline lavage in rabbit and determined the expression of VEGF in lung tissues with inflammatory cytokines. We made animal models of sepsis of longer duration and generated survival curves in context to various drug treatments. We studied the relation of VEGF with altered hemodynamic state in sepsis at both compensatory and decompensatory phases. Besides, we generated acute and chronic models of sepsis and examined the organ specific expression of VEGF in relation to organ morphology and organ dysfunction. In addition, organ specific VEGF expression has also been studied in several animal models of sepsis namely mouse, rat and rabbit models. We also made the diabetic animals and then induced sepsis in diabetic models at pilot study level.
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| 今後の研究の推進方策 |
We already used several pharmacological approaches to reverse the organ specific VEGF expression alteration in sepsis of several duration and doses. Last year we mainly concentrated to lung and heart tissues in septic models. Now we are systematically investigating the effects of several drug treatments on VEGF expression in liver, kidney and brain tissues in sepsis. Based on our data on endothelin blockade in sepsis models, we also tend to investigate whether endothelin blockade has any role in regulating VEGF expression in several organs in sepsis. In addition, this year brain, heart, lung, liver and kidney tissues will be taken out from both septic animal with or without drug treatment, including control animal samples and will be used for RNA isolation and microarray analysis, and ultimately identification of the differentially expressed genes. Determination of common gene expression signature, validation of common gene signature by real-time PCR, and bioinformatics analysis (functional, ontology, biological process, clustering, pathways and network analysis) will be also performed. We will also establish a technique to visualize the microcirculation in kidney tissues in sepsis. In addition, as VEGF plays crucial roles in organ dysfunction in both sepsis and diabetes, now we are also generating diabetic sepsis models and organ specifically checking whether diabetes can be an aggravating factor in alteration of VEGF expression in septic organs. This year we will produce sepsis models in genetically manipulated animals and will investigate organ specific VEGF expression.
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