GROWTH RETARDATION IN CHRONIC RENAL FAILURE

描述（改编自申请人的摘要）：虽然增长 迟缓是慢性肾衰竭儿童的严重并发症 (CRF)其发病机制尚不清楚。 长期目标是 研究的目的是制定预防和治疗策略， 基于对CRF儿童生长迟缓的认识， 其分子病理生理学。 使用胫骨的原代培养， 慢性肾衰生长迟缓大鼠模型中的骺软骨细胞，生长 细胞生长激素（GH）和胰岛素样生长因子（IGF）-I抵抗 增长反应已经得到证实。 两个特定的分子缺陷， GH-IGF-I轴已在CRF软骨细胞中鉴定。 生长激素 受体（GHR）mRNA（北方印迹）和蛋白质（免疫印迹）均为 CRF软骨细胞减少，可能是GH抵抗的原因。 细胞内磷脂酰肌醇（PI）3激酶蛋白（85 kDa亚基）是 减少CRF软骨细胞，并可能解释IGF-I抵抗。 将在CRF中研究这些分子异常的潜在机制。 实验将被设计来测试升高的GH和肾上腺皮质激素的作用。 糖皮质激素以及1，25维生素D3缺乏症的发病机制 CRF中GH-IGF-I缺陷。 假设这些分子缺陷 GH-IGF-I轴的异常在GH、IGF-I抵抗的发病机制中起重要作用 和CRF软骨细胞生长迟缓。 的作用 通过测量IGF-I来检查CRF软骨细胞中的局部GH-IGF-I轴 用GH刺激的mRNA产生以及用GH和 IGF-1抗体在CRF和对照软骨细胞中共孵育。 的 渥曼青霉素特异性抑制PI 3激酶对生长的影响 将在正常软骨细胞中检测免疫应答和IGF-I敏感性。 的 GH-IGF-I轴的局部作用，在面对这些双重分子缺陷， CRF将在分子和自分泌/旁分泌水平上进行整合。 最后，使用GHR（和PI 3）的融合基因进行体外基因转移研究 激酶）和报告基因与脂质体转染系统的连接， 检查这些分子异常的正常化是否会导致 CRF中GH、IGF-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.