Early Validation of Urinary Biomarkers of Renal Obstruction

描述(申请人提供)：肾梗阻，或输尿管肾盂交界处梗阻(UPJO)，可导致肾功能丧失和肾脏发育异常。适当的早期手术干预可以预防肾损害。临床上的难题是确定哪些儿童需要干预，以及何时需要干预。肾梗阻总是导致肾积水或肾脏扩张；然而，肾积水并不总是表明临床上有明显的梗阻。更令人困惑的是，高达5%的孕妇被诊断为产前肾积水，其中30%可能是由UPJO引起的。这大大增加了可能需要在出生后进行筛查的儿童数量。目前的诊断仅限于具有侵入性的成像方式，将儿童暴露在电离辐射下，可能需要全身麻醉，并受到其主观性质的限制。虽然有很好的手术治疗，但(1)没有明确的临床测试来确定谁患有肾积水需要手术；(2)没有既定的出生后诊断测试或干预的临床指南；(3)没有能力确定谁有可能面临未来长期肾脏损害的风险。迫切需要一种更准确的非侵入性检测来标准化临床指南、诊断和管理。使用我们实验室开发的基于质谱学(MS)的方法，我们从1114多个蛋白质中确定了UPJO的76个潜在尿标记物的候选列表，这些蛋白质是在对梗阻的尿蛋白组进行的无偏见的定量发现研究中确定的。有趣的是，有一组特定的蛋白质(24)与氧化应激有关，它们在尿液中具有显著的数量倍数差异。此外，来自另外一组队列的数据确定了尿基质金属蛋白酶(MMPs)作为UPJO临床生物标记物的潜在作用。我们的数据表明，有一些特定的尿液生物标志物有可能确定哪些患有肾积水的儿童需要手术治疗UPJO。在这项建议中，我们提出了第一个作为UPJO诊断工具的候选尿标志物的严格早期验证试验。我们假设UPJO儿童的尿蛋白质组包含临床上有用的肾梗阻生物标志物，这些生物标志物将无创性地确定哪些儿童应该接受手术干预和观察。我们将通过以下具体目标挑战这一假设：1)使用定向MS和基质金属蛋白酶图谱，在UPJO患者非侵入性获取的尿液中确定“最佳”标记物组合。2)确定UPJO标志物的“最佳”小组是否允许在纵向混合疾病队列中对肾积水患者进行分层。这些研究是专门为预先验证尿液生物标志物而设计的，这些生物标志物有可能显著改变和改善大量患有肾积水的儿童的临床管理。这些高转移性实验的结果可能是前瞻性临床试验的基础。

DESCRIPTION (provided by applicant): Renal obstruction, or ureteropelvic junction obstruction (UPJO), can result in loss of kidney function and abnormal renal maturation. Appropriate early surgical intervention may prevent renal damage. The clinical dilemma is identifying which children need intervention and when. Renal obstruction always results in hydronephrosis, or dilation of the kidney; however, hydronephrosis does not always indicate clinically significant obstruction. To further compound the quandary, up to 5% of all pregnancies have a diagnosis of prenatal hydronephrosis, in which 30% may be caused by UPJO. This considerably increases the number of children who may need screening after birth. Current diagnostics are constrained to imaging modalities that are invasive, expose the children to ionizing radiation, may require general anesthesia, and are limited by their subjective nature. Although excellent surgical treatment exists, there are (1) NO definitive clinical tests that determine who with hydronephrosis requires surgery; (2) NO established clinical guidelines for postnatal diagnostic testing or intervention; and (3) NO ability to determine who is at risk for future long-term renal damage. A more accurate non-invasive test to standardize clinical guidelines, diagnosis, and management is sorely needed. Using a mass spectrometry (MS) based method developed in our laboratory; we identified a candidate list of 76 potential urinary biomarkers of UPJO from over 1114 proteins identified in an unbiased quantitative discovery study of the obstructed urinary proteome. Interestingly, there was a particular subset of proteins (24) involved with oxidative stress that had dramatic quantitative fold differences in the urine. I addition, data generated from an additional cohort identified a potential role of urinary matrix metalloproteinases (MMP) as a clinical biomarker for UPJO. Our data suggests that there are specific urinary biomarkers that have the potential to determine which children with hydronephrosis require surgical intervention for UPJO. In this proposal we present the first rigorous early-validation trial of candidate urinary markers as diagnostic tools for UPJO. We hypothesize that the urinary proteome of children with UPJO contains clinically useful biomarkers of renal obstruction that will non-invasively determine which children should undergo surgical intervention versus observation. We will challenge this hypothesis with the following specific aims: 1) Identify the "best" panel of markers in noninvasively obtained urine from the bladder of UPJO patients using directed MS and MMP profiling. 2) Determine if the "best" panel of UPJO markers allows for stratification of patients with hydronephrosis in a longitudinal mixed disease cohort. These studies are specifically designed to pre-validate urinary biomarkers that have the potential to significantly alter and improve the clinical management of a very large population of children with hydronephrosis. The findings of these highly translational experiments may be the basis for a prospective clinical trial.