RENAL AND CELLULAR STUDIES IN TYPE I DIABETIC PATIENTS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 糖尿病肾病(DN)是导致肾功能衰竭的主要原因，但对其发病机制的了解仍然有限。这些研究的目的是：(A)基于对个体胰岛素依赖型糖尿病(IDDM)患者细胞的体外研究，开发与肾脏活检终点相关的危险标志物，(B)询问这些标志物是否代表遗传决定的过程，以及(C)确定细胞外基质(ECM)分子及其酶和酶调节因子、生长因子、葡萄糖转运体和钠/氢逆向转运体的细胞(体外)表达与肾脏结构和功能终点之间的关系，以探讨糖尿病肾病的基本发病机制；开发DNA和培养细胞的资料库，以评估被证明与糖尿病肾病风险有关的基因变异对细胞功能的影响。将研究三组患者：(A)早期(~10年)和长期(~20年)IDDM患者，分为两组，DM病变进展缓慢或迅速，(B)符合IDDM的同胞对，和(C)同卵双胞胎不符合IDDM。糖尿病肾病将通过形态计量学的方法进行量化，并根据病程进行因子分析，或用相隔5年的2次活检来表示。主要终点将是通过电子显微镜形态计量学分析测量的系膜体积分数[VV(MES/GLOM)]。对长期IDDM患者的横断面研究将允许识别与糖尿病肾病病变和临床肾脏异常发展非常快或非常缓慢相关的细胞标志物。在短期“快”和“慢”患者和IDDM同胞配对中进行的纵向研究(5年)将允许考虑血糖、血压和其他“环境变量”。培养的皮肤成纤维细胞(SF)将使用逆转录聚合酶链式反应(RT-PCR)评估上述分子的mRNA表达。选择SF是因为他们的表型变化发生在“快速通道”的IDDM患者中，并且在兄弟姐妹对中相关。这些研究将确定糖尿病肾病病变与SF行为的关系，并评估与糖尿病肾病病变一致的IDDM同胞对的这种行为是否一致。来自非糖尿病同卵双胞胎的SF将回答高血糖是否是糖尿病肾病风险的细胞标志物表达所必需的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Diabetic nephropathy (DN) is the leading cause of renal failure, yet pathogenetic understanding remains limited. Objectives of these studies are (a) to develop risk markers based on in vitro studies of cells derived from individual insulin dependent diabetic (IDDM) patients, which are related to renal biopsy endpoints, (b) to ask if these markers represent genetically determined processes and (c) to define relationships between cellular (in vitro) expression of mRNA for extracellular martix (ECM) molecules, their enzymes and enzyme regulators, growth factors, glucose transporters, and sodium/hydrogen antiporter and renal structural and functional endpoints in order to explore basic pathogenic mechanisms in DN; to develop a repository of DNA and cultured cells that will allow evaluation of the cellular functional consequences of genetic variations shown to be linked to DN risk. Three patient groups will be studied: (a) early (~10 years) and long-term (~20 years) IDDM duration patients dichotomized into 2 groups with slow or rapid development of DM lesions, (b) sibling pairs concordant for IDDM, and (c) identical twins discordant for IDDM. DN will be quantitated morphometrically, and factored for duration or expressed as a rate determined by 2 biopsies 5 years apart. The primary endpoint will be mesangial volume fraction [Vv(Mes/glom)] measured by electron microscopic morphometric analysis. Cross-sectional studies of long-term IDDM patients will allow the identification of cellular markers associated with very rapid or very slow development of DN lesions and clinical renal abnormalities. Longitudinal studies (5 year) in shorter-term "fast" and "slow-track" patients and IDDM sibling pairs will allow factoring for glycemia and blood pressure and other "environmental variables." Cultured skin fibroblasts (SF) from individual patients will be evaluated for mRNA expression for the above listed molecules using reverse transcriptase polymerase chain reaction. SF are selected since changes in their phenotype occur in "fast-track" IDDM patients and are correlated in sibling pairs. These studies will determine the relationship of DN lesions to SF behavior and evaluate whether this behavior is concordant in IDDM sibling pairs who are concordant for DN lesions. SF from nondiabetic identical twins will answer whether hyperglycemia is necessary for the expression of cellular markers of DN risk.