Digestive Enzymes and Microvascular Inflammation in Shock

项目总结/摘要 生理性休克和多器官功能衰竭是最重要的医学问题之一，死亡率高。 一个强大的炎症级联反应伴随着休克，但目前还没有共识的触发机制， 炎症我们的长期目标是确定休克中炎症的起源， 新的干预措施，以尽量减少炎症和多器官衰竭。我们最近开发了一种新的 这项研究已经确定了肠道中的胰腺消化酶是休克的关键因素。这 作为正常消化的一部分，酶家族通常局限于肠腔。消化 作为正常消化的一部分，酶以相对高的浓度存在，能够降解 大多数生物分子和整个组织都能在几小时内完成在正常情况下，消化系统 酶被粘膜屏障保留在肠腔内。但在休克状态下， 相同的消化酶从肠腔输送到肠壁中。一旦进入墙内， 它们启动了一个自动消化过程，释放胰腺酶以及炎症性消化， 这些物质进入中央循环，在那里它们引起细胞损伤和多器官衰竭。我们获得 初步证据表明，肠腔中消化酶的阻断 显著减少炎症介质的产生，并显著改善严重 休克的形式。我们的假设是，在失血性休克中，正常情况下由内皮细胞提供的保护屏障 刷状缘上皮受损，允许预先存在的消化酶进入间质 肠壁中的组织消化酶通过多种途径进入中央 在循环中，它们通过酶促裂解 膜受体，例如紧密连接蛋白的细胞外结构域的切割和不可逆的 上皮和内皮通透性升高或胰岛素细胞外结合位点裂解 受体和胰岛素抵抗。阻断胰腺酶和暂时阻止消化， 肠腔用于预防炎症并降低由于多器官衰竭而导致的死亡率。因此 我们建议研究以下三个重要的具体目标：1。确定失血性休克中 胰腺消化酶从肠腔沿沿着多个通道的活性和运输 进入外周微循环的途径和相关微血管炎症的水平 反应2.通过酶的阻断作用确定肠腔内胰腺消化的作用 酶在炎症和细胞毒性介质的产生以及出血后的长期生存中的作用 冲击. 3.测量与紧密结合失败相关的蛋白酶对细胞外受体的切割水平。 在休克的早期阶段，连接和关键细胞功能的丧失。这些研究将决定 休克中强大的细胞和器官损伤机制的起源机制。我们将测试一种新的形式 对休克高死亡率的干预可能具有临床实用性。

Project Summary/Abstract Physiological shock and multi-organ failure is one of the most important medical problems with high mortality. A powerful inflammatory cascade accompanies shock, but there is no consensus for the trigger mechanisms of the inflammation. It is our long-term objective to identify the origin of the inflammation in shock and develop new interventions to minimize the inflammation and multi-organ failure. We recently developed a new line of research that has served to identify pancreatic digestive enzymes in the intestine as key players in shock. This family of enzymes is usually restricted to the lumen of the intestine as part of normal digestion. The digestive enzymes are present in comparatively high concentrations as part of normal digestion, capable to degrade most biological molecules and entire tissues within hours. Under normal circumstances, the digestive enzymes are retained within the lumen of the intestine by the mucosal barrier. But under conditions of shock, the same digestive enzymes are transported from the lumen into the wall of the intestine. Once inside the wall, they initiate an auto-digestion process with release of pancreatic enzymes as well as inflammatory digestive products into the central circulation where they cause cell injury and multi-organ failure. We obtained preliminary evidence to indicate that blockade of the digestive enzymes in the lumen of the intestine dramatically reduces the production of inflammatory mediators and significantly improves survival after severe forms of shock. It is our hypothesis that in hemorrhagic shock the protective barrier normally provided by the brush border epithelium is compromised and allows access of preexisting digestive enzymes into interstitial tissue in the wall of the intestine. The digestive enzymes are carried through multiple pathways into the central circulation where they cause microvascular inflammation and major cell dysfunctions by enzymatic cleavage of membrane receptors, e.g. cleavage of the extracellular domain of tight junction proteins and irreversible elevation of epithelial and endothelial permeability or cleavage of the extracellular binding site of the insulin receptor and insulin resistance. Blockade of the pancreatic enzymes and temporary prevention of digestion in the lumen of the intestine serves to prevent inflammation and reduces mortality due to multi-organ failure. Thus we propose to investigate the following three important Specific Aims: 1. Determine in hemorrhagic shock the activity and transport of the pancreatic digestive enzymes from the lumen of the intestine along multiple pathways into the peripheral microcirculation and the level of the associated microvascular inflammatory reaction. 2. Determine by enzyme blockade in the lumen of the intestine the role of pancreatic digestive enzymes in generation of inflammatory and cytotoxic mediators and in long-term survival after hemorrhagic shock. 3. Measure the level of extracellular receptor cleavage by proteases associated with failure of tight junctions and loss of key cell functions during the early stage of shock. These studies will determine the mechanisms for the origin of the powerful cell and organ injury mechanisms in shock. We will test a new form of intervention against the high mortality in shock that may have clinical utility.