Role of Cytokines in Sepsis and Trauma

描述(申请人提供)：脓毒症仍然是一个严重的临床问题，具有相当高的发病率和死亡率，即使在广泛的调查之后，我们对疾病过程的基本机制的理解仍有一些重要的、未解决的问题。以前的治疗尝试大多是针对全球钝化脓毒症的炎症反应。我们使用盲肠结扎和穿孔(CLP)诱导的小鼠脓毒症模型，仔细研究了脓毒症的基本机制，发现脓毒症早期(前5天)和晚期(5天以后)之间存在重要差异。CLP的实施方式可能会导致50%的死亡率，但准确预测哪些小鼠将存活一直是一个挑战。与100%致死率的模型相比，50%致死率的CLP模型提供了更多的洞察力，因为治疗可以增加或减少存活率，使研究结果更具临床相关性。我们已经确定了准确预测5天脓毒症存活期的生物标志物。这些生物标记物可以在老鼠身上进行研究，而这在几年前是不可行的。动物在败血症死亡前的前5天可能会被处死，并进行分析以评估随后死亡的机制。具体目标一将试图通过加强中性粒细胞在腹膜腔内的早期募集来提高存活率，以帮助根除感染的焦点。将进行毒性研究，以解决局部中性粒细胞水平增加是否会导致实质性器官损伤的问题。具体目标二将着眼于针对肠道细菌的自然产生的IgM抗体水平的增加是否作为结果的主要决定因素。这符合这样的假设，即对脓毒症的反应的复杂性的一部分是在脓毒症发生之前循环抗体的存在，这些抗体会破坏细菌，以增强它们的吞噬作用和中性粒细胞的杀伤作用。在第三个具体目标中，我们将评估脓毒症早期阶段的个体化治疗，使用我们新的多重格式来测量脓毒症早期阶段的细胞因子。我们的工作已经确定了能够准确预测后续死亡率的关键血浆细胞因子水平。只有那些在与致命性相关的范围内升高的细胞因子才会被阻止，而不是像大剂量糖皮质激素那样发生的全局钝性炎症。最后一个具体目标将着眼于脓毒症的慢性期，即发生在CLP后第5天之后的阶段。其中一些小鼠死于过度炎症，一些小鼠死于迟钝的炎症反应。再次使用多元化方法，我们将针对单个动物量身定制治疗方法。我们的主要假设是，脓毒症的炎症反应是动态的，最佳治疗需要个体化或针对早期根除细菌。通俗语言：许多患者即使接受了正确的抗生素治疗，仍然死于严重的细菌感染。目前尚不清楚这些患者的死亡原因。我们将使用动物模型来确定细菌是如何伤害和杀死患者以及如何预防的。与公共卫生相关：许多患者仍然死于严重的细菌感染，即使他们接受了正确的抗生素治疗。目前尚不清楚这些患者的死亡原因，也不清楚治疗这些患者的最佳方法。我们将使用动物模型来帮助我们了解细菌是如何杀死病人的，以及如何预防这种情况。

DESCRIPTION (provided by applicant): Sepsis remains a serious clinical problem with substantial morbidity and mortality and even after extensive investigation there are important, unresolved issues in our understanding of the basic mechanisms of the disease process. Previous attempts at therapy were mostly directed at globally blunting the inflammatory response to sepsis. We have used the murine model of sepsis induced by cecal ligation and puncture (CLP) to closely examine basic mechanisms and find important differences between the early (first 5 days) and late phase of sepsis (beyond day 5). CLP may be performed in a manner to cause 50% mortality but a challenge has been to predict accurately which mice will live. A CLP model with 50% lethality provides much greater insight compared to a model with 100% lethality since therapies may increase or decrease survival, making the findings more clinically relevant. We have identified biomarkers which accurately predict 5 day sepsis survival. These biomarkers allow studies in mice which were not feasible even a few years ago. Animals may be sacrificed during the first 5 days of sepsis prior to their demise and analyses performed to evaluate mechanisms of subsequent mortality. Specific aim one will attempt to improve survival by enhancing early recruitment of neutrophils into the peritoneal cavity to help eradicate the focus of infection. Toxicity studies will be performed to address the issue of whether increasing local levels of neutrophils contributes to substantial organ injury. Specific aim two will look at whether increased levels of naturally occurring IgM antibodies directed against enteric bacteria serve as a primary determinant of outcome. This fits with the hypothesis that a portion of the complexity of the response to sepsis is the presence of circulating antibodies prior to the onset of sepsis which would opzonize bacteria to enhance their phagocytosis and killing by the neutrophils. In the third specific aim we will evaluate individually tailoring therapy in the early stages of sepsis using our novel multiplex format for measuring cytokines during the early phase of sepsis. Our work has identified critical plasma cytokine levels that accurately predict subsequent mortality. Only those cytokines which are elevated in the range associated with lethality will be blocked, rather than globally blunting inflammation such as occurs with high-dose glucocorticoids. The last specific aim will look at the chronic phase of sepsis, that which occurs beyond day 5 after CLP. Some of these mice died with excessive inflammation and some of them died with a blunted inflammatory response. Again using the multiplex approach we will tailor the therapy to the individual animal. Our overarching hypothesis is that the septic inflammatory response is dynamic and optimal therapy needs to be individually tailored or directed to early eradication of bacteria. Lay Language: Many patients still die from severe bacterial infections even when they are treated with the correct antibiotics. It is not clear why these patients die. We will use an animal model to determine how bacteria injure\kill patients and how to prevent this. PUBLIC HEALTH RELEVANCE: Many patients still die from severe bacterial infections even when they are treated with the correct antibiotics. It is not clear why these patients die, or the best method to treat the patients. We will use an animal model to help us understand how bacteria kill patients and how to prevent this.