The Urinary Proteome and Renal Function Loss in Diabetes

描述(由申请人提供)：近几十年来，糖尿病引起的终末期肾病(ESRD)的风险增加了两倍。尽管广泛使用抗高血压药物和血管紧张素转换酶抑制剂进行治疗，这种情况还是发生了。ESRD的流行是由于糖尿病患者发生肾功能丧失的比例实际增加，而不是这些患者存活率提高的结果。为了控制这一流行，迫切需要研究努力确定糖尿病肾功能丧失的决定因素和机制，以便开发新的预防计划。尤其缺乏关于早期肾功能下降的启动和促进的知识。最近，我们发现，一旦出现微量白蛋白尿(MA)，很大一部分1型糖尿病患者的肾功能开始下降。这种早期肾功能下降与尿白蛋白排泄水平的进一步增加无关，但与尿液趋化因子水平的升高有关。对这些患者的尿蛋白进行了初步的蛋白质组学分析，发现MA患者的尿中存在特异性蛋白，且早期肾功能下降，而MA患者和肾功能稳定的患者的尿液中没有这种蛋白。这些未知的尿蛋白代表了暴露于损害MA患者近端小管的候选物质，并导致尿液趋化因子升高。我们的目标是确定与早期肾功能下降最相关的蛋白质。此外，我们建议使用蛋白质组分析方法来表征尿趋化因子，以区分有早期肾功能下降风险的MA患者和那些肾功能稳定的MA患者。这些问题将在1型和2型糖尿病患者中进行检查。这项建议的具体目标是：1)确定MA和1型糖尿病(n=300)和2型糖尿病(n=500)两组患者早期显著肾功能下降的频率。2)通过比较早期肾功能减退患者和肾功能稳定的对照组的尿蛋白谱，采用基于质谱仪的蛋白质组学分析方法，确定导致两组人群早期肾功能减退的尿蛋白(S)。3)使用有针对性的蛋白质组学方法和Luminex技术，确定尿液和血浆细胞因子/趋化因子图谱，预测两组患者早期肾功能下降。4)结合上述研究结果，建立1型、2型糖尿病和MA患者早期肾功能下降的病因学模型。关于早期肾功能下降的机制和决定因素的拟议研究是新颖的，并将为开发有效的预防糖尿病肾功能丧失的方法提供数据。

DESCRIPTION (provided by applicant): The risk of End Stage Renal Disease (ESRD) due to diabetes has tripled in recent decades. This has occurred despite widespread implementation of treatment with antihypertensive drugs and ACE inhibitors. This epidemic of ESRD is due to a real increase in the proportion of diabetic patients developing renal function loss rather than a consequence of improved survival of these patients. To contain this epidemic, research efforts are urgently needed to identify the determinants and mechanisms of renal function loss in diabetes so that new preventive programs can be developed. Particularly lacking is knowledge about the initiation and promotion of the early renal function decline. Recently, we found that renal function begins to decline in a large proportion of patients with type 1 diabetes once microalbuminuria (MA) develops. This early renal function decline was unrelated to further increases in the level of urinary albumin excretion but was associated with elevated levels of urinary chemokines. Preliminary proteomic analysis of urine from these patients revealed the presence of specific proteins in the urine of individuals with MA and early renal function decline that were absent in the urine of individuals with MA and stable renal function. These unknown urinary proteins represent candidates for exposures that injure the proximal tubules of patients with MA and are responsible for the elevated urinary chemokines. We aim to identify the proteins most associated with early renal function decline. Furthermore, we propose to use methods of proteomic analysis to characterize the urinary chemokines that distinguish patients with MA who are at risk of early renal function decline from those with stable renal function. These questions will be examined in both type 1 and type 2 diabetes. The Specific Aims of this proposal are: 1) To determine the frequency of significant early renal function decline in two cohorts of individuals with MA and type 1 diabetes (n=300), and type 2 diabetes (n=500). 2) To identify urinary protein(s) that cause early renal function decline in both cohorts by comparing urinary protein profiles between cases with early renal function decline and controls with stable renal function using proteomics analysis based on mass spectrometry. 3) To identify urinary and plasma cytokine/chemokine profiles that predict early renal function decline in the two cohorts using a targeted proteomics approach and Luminex technology. 4) To develop an etiologic model of early renal function decline in individuals with type 1 and type 2 diabetes and MA incorporating all the findings from these studies. The proposed research on the mechanisms and determinants of early renal function decline is novel and will provide data for the development of effective methods of prevention of renal function loss in diabetes.