Novel diagnostic and stratification tools for septic shock

描述（由申请人提供）：感染性休克仍然是成人和儿童的主要公共卫生问题。该领域的一个重要且未得到满足的临床差距是缺乏针对感染性休克的强大分层和诊断工具。这项建议旨在直接解决这一差距。我们利用我们广泛的、多中心的感染性休克儿童基因表达数据库来识别基因特征，为临床感染性休克的新型分层和诊断工具的开发提供了坚实的基础。该提案的主要创新是能够直接利用转录组数据作为临床进步的基础，这是转录组学经常陈述但很少实现的目标。我们提出了三个独立但高度互补的具体目标，所有这些目标都直接解决了上述未满足的临床差距。在具体目标1中，我们将检验84个基因的mRNA表达可以提高现有验证模型的准确性的假设，以更可靠地分层感染性休克儿童的死亡或生存风险。我们已经确定了84个候选分层基因具有预测能力的死亡率/生存。使用数字mRNA测量平台，我们将整合来自这84个基因的mRNA表达数据，以增强最近开发的基于血清蛋白生物标志物的模型的预测能力。增强模型将在现有的300例患者队列中推导，随后在前瞻性入组的200例患者队列中验证。在具体目标2中，我们将检验白细胞介素-27可以作为细菌感染的诊断生物标志物的假设。我们已经确定IL-27作为细菌感染的候选诊断生物标志物。在一组危重患儿中，我们已经证明IL-27血清蛋白浓度可以预测细菌感染，特异性和阳性预测值> 90%。我们将在从急诊科和重症监护室招募的两个单独的患者队列中进一步测试血清IL-27蛋白浓度作为诊断生物标志物的能力。在具体目标3中，我们将检验存在一组以糖皮质激素受体（GCR）表达降低为特征的脓毒性休克患者的假设。我们的基因表达数据已经确定了一组感染性休克患者，其特征在于与GCR信号通路相对应的基因的广泛抑制，与其他两组没有GCR信号通路基因抑制的患者相比，这组特定患者具有更高的疾病严重程度和死亡率。这表明存在一组可识别的感染性休克患者，他们对糖皮质激素的反应相对较低。如果这是真的，它将成为研究促皮质激素对感染性休克作用的一个主要混杂因素，这是目前该领域的一个主要争议。我们已经开发了一种基于流式细胞术的协议，直接测量GCR表达的感染性休克患者的血液室。我们将系统地测量GCR表达，并将GCR表达与临床表型相关联。总的来说，这三个目标有可能大大推进临床感染性休克的分层和诊断设备。

DESCRIPTION (provided by applicant): Septic shock continues to be a major public health problem in both adults and children. An important and unmet clinical gap in the field is the lack of robust stratification and diagnostic tools specific for septic shock. This proposal seeks to directly address this gap. We have leveraged our extensive, multi-center gene expression databank of children with septic shock to identify gene signatures that provide a strong foundation for the development of novel stratification and diagnostic tools for clinical septic shock. The major innovation of this proposal is the ability to directly leverage transcriptomic dat as a basis for clinical advancements, an often stated, but seldom achieved goal of transcriptomics. We are proposing three independent, but highly complementary Specific Aims, all of which directly address the aforementioned, unmet clinical gap. In Specific Aim 1, we will test the hypothesis that the mRNA expression of 84 genes can enhance the accuracy of an existing, validated model to stratify more reliably the risk of death or survival in children with septic shock. We have identified 84 candidate stratification genes having predictive capacity of mortality/survival. Using a digital mRNA measurement platform, we will incorporate the mRNA expression data from these 84 genes to enhance the predictive capacity of a recently developed, serum protein biomarker-based model. The enhanced model will be derived in an existing cohort of 300 patients, and subsequently validated in a prospectively enrolled cohort of 200 patients. In Specific Aim 2, we will test the hypothesis that interleukin-27 can serve as a diagnostic biomarker for bacterial infection. We have identified IL-27 as a candidate diagnostic biomarker for bacterial infection. In a cohort of critically ill children, we have demonstrated tha IL-27 serum protein concentrations can predict bacterial infection with a specificity and positive predictive value of >90%. We will further test the ability of serum IL-27 protein concentration to serve as a diagnostic biomarker in two separate cohorts of patients recruited from the Emergency Department and the Intensive Care Unit. In Specific Aim 3, we will test the hypothesis that there exists a group of patients with septic shock characterized by decreased expression of the glucocorticoid receptor (GCR). Our gene expression data have identified a group of patients with septic shock who are characterized by widespread repression of genes corresponding to the GCR signaling pathway, and this particular group of patients has higher illness severity and mortality, compare to two other groups without repression of GCR signaling pathway genes. This suggests the existence of an identifiable group of patients with septic shock who are relatively less responsive to adjunctive glucocorticoids. If this holds true, it woul represent a major confounder for studying the role of adjunctive corticosteroids for septic shock, which is currently a major controversy in the field. We have developed a flow cytometry-based protocol to directly measure GCR expression in the blood compartment of patients with septic shock. We will systematically measure GCR expression and correlate GCR expression with clinical phenotypes. Collectively, these three Aims have the potential to substantially advance the stratification and diagnostic armamentarium for clinical septic shock.