GROWTH RETARDATION IN CHRONIC RENAL FAILURE

描述(改编自申请者的摘要)：虽然成长 发育迟缓是慢性肾功能衰竭儿童的严重并发症 (CRF)，其发病机制尚不清楚。这样做的长期目标是 研究是为了制定预防和治疗策略 慢性肾功能衰竭儿童生长迟缓的认知治疗 它的分子病理生理学。使用胫骨的原代培养 慢性肾功能衰竭大鼠生长迟缓模型中的骨骺软骨细胞 细胞内激素(GH)和胰岛素样生长因子(IGF)-I抵抗 增长反应已经被证明。两个特定的分子缺陷 已在CRF软骨细胞中发现了GH-IGF-I轴。生长激素 受体(GHR)mRNA(Northern印迹)和蛋白质(免疫印迹)都是 CRF软骨细胞减少，可能是GH抵抗的原因。 胞内磷脂酰肌醇(PI)3蛋白(85 kDa亚基)是 在CRF软骨细胞中减少，可能是IGF-I抵抗的原因。 这些分子异常的机制将在CRF中进行研究。 实验将被设计用来测试升高的生长激素和肾上腺的作用 糖皮质激素和1，25维生素D3缺乏在糖尿病发病机制中的作用 慢性肾衰患者的GH-IGF-I缺陷。假设这些分子缺陷 在生长激素-胰岛素样生长因子-I轴在生长激素、胰岛素样生长因子-I抵抗的发病机制中起重要作用 以及CRF软骨细胞的生长迟缓，将进行测试。美国政府的角色 将通过测定IGF-I来检测CRF软骨细胞中局部的GH-IGF-I轴 生长激素刺激下的mRNA生成以及生长激素和生长激素的生长反应 胰岛素样生长因子-I抗体在CRF和对照软骨细胞中共孵育。这个 Wortmannin特异性抑制PI3激酶对生长的影响 反应和IGF-I敏感性将在正常软骨细胞中进行检测。这个 GH-IGF-I轴的局部作用，面对这些双分子缺陷 CRF，将在分子和自分泌/旁分泌水平上整合。 GHR(和PI3)融合基因的体外基因转移研究 和带有脂联素系统的报告基因将被执行 检查这些分子异常的正常化是否会导致 CRF患者生长激素、胰岛素样生长因子-I抵抗和生长迟缓的纠正 软骨细胞。

DESCRIPTION (Adapted from the Applicant's Abstract): Although growth retardation is a serious complication in children with chronic renal failure (CRF), its pathogenesis is poorly understood. The long-term goal of this research is to develop therapeutic strategies for the prevention and treatment of growth retardation in children with CRF based on understanding of its molecular pathophysiology. Using a primary culture of tibial epiphyseal chondrocytes in a rat model of growth retardation in CRF, growth hormone (GH) and insulin-like growth factor(IGF)-I resistance in cellular growth responses have been demonstrated. Two specific molecular defects in the GH-IGF-I axis have been identified in CRF chondrocytes. Growth hormone receptor(GHR) mRNA (Northern blot) and protein (immunoblot) are both decreased in CRF chondrocytes and may account for GH resistance. Intracellular phosphatidyl-inositol(PI) 3 kinase protein (85 kDa subunit) is decreased in CRF chondrocytes and may account for IGF-I resistance. Mechanisms underlying these molecular abnormalities will be studied in CRF. Experiments will be designed to test the roles of elevated GH and adrenal glucorticoids as well as 1,25 vitamin D3 deficiency in the pathogenesis of the GH-IGF-I defects in CRF. The hypothesis, that these molecular defects in GH-IGF-I axis are important in the pathogenesis of GH, IGF-I resistance and growth retardation in CRF chondrocytes, will be tested. The role of the local GH-IGF-I axis in CRF chondrocytes will be examined by measuring IGF-I mRNA generation with GH stimulation as well as growth responses with GH and IGF-I antibody co-incubation in both CRF and control chondrocytes. The effects of specific inhibition of PI3 kinase (by wortmannin) on growth response and IGF-I sensitivity will be examined in normal chondrocytes. The local role of GH-IGF-I axis, in the face of these dual molecular defects in CRF, will be integrated at molecular and autocrine/paracrine levels. Finally in vitro gene transfer studies using fusion genes of GHR (and PI3 kinase) and a reporter gene with a lipofectin system will be performed to examine if normalization of these molecular abnormalities will lead to correction of GH, IGF-I resistance, and growth retardation in CRF chondrocytes.