Disorders of Copper Transport

Menkes病是一种X连锁隐性铜转运障碍，由编码进化上保守的铜转运ATP酶的基因缺陷引起。在哺乳动物中，该基因产物作为细胞内泵将铜转运到trans-Golgi空间以并入铜需要酶中，并且还介导铜从细胞中流出。这种疾病在婴儿期出现，发育迟缓，无法茁壮成长，神经变性和过早死亡（通常在3岁之前）。我们对这种疾病的工作包括开发快速可靠的神经化学和分子技术进行早期诊断，这些努力与受影响婴儿的早期组氨酸铜治疗的临床试验相吻合。我们使用细胞生物学，分子和生物化学方法来表征入组的患者，并与神经发育结果相关。患者成纤维细胞的共聚焦成像用于评估突变Menkes基因产物的数量和定位。血脑屏障在许多门克斯病患者中构成了一个具有挑战性的治疗障碍，我们假设了少数患者（约1/5）对早期组氨酸铜成功应答（正常神经发育结局）的治疗应答率的分子基础。这些患者的突变使至少一些残留的铜能够转运到发育中的大脑。因此，我们正在开发替代治疗方法，包括脑室内铜管理，绕过血脑屏障。为了评估安全性，并确定最大耐受剂量（MTD）的组氨酸铜，我们开始了动物方案的脑室内组氨酸铜管理在成年雄性大鼠，并建立了最大耐受剂量为0.5？G.这些研究发现，接受MTD组氨酸铜和生理盐水处理对照组的动物在行为、生长或脑组织病理学方面无统计学显著差异。这些研究结果是相关的，以确定一个合适的脑室内剂量为人类管理选定的门克斯病患者。

Menkes disease is an X-linked recessive disorder of copper transport caused by defects in a gene that encodes an evolutionarily conserved copper-transporting ATPase. In mammals, this gene product functions as an intracellular pump to transport copper into trans-Golgi spaces for incorporation into copper-requiring enzymes, and also mediates copper exodus from cells. The disorder presents in infancy with delayed development, failure to thrive, neurodegeneration, and premature death (typically by 3 years of age). Our work on this disorder includes development of rapid and reliable neurochemical and molecular techniques for very early diagnosis, efforts which dovetail with a clinical trial of very early copper histidine treatment for affected infants. We use cell biological, molecular, and biochemical approaches to characterize enrolled patients and to correlate with neurodevelopmental outcomes. Confocal imaging of patient fibroblasts is used to assess quantity and localization of mutant Menkes gene products. The blood-brain barrier poses a challenging treatment obstacle in many Menkes disease patients, and we hypothesized a molecular basis for treatment responsivity in the minority of patients (about 1 in 5) who respond successfully (normal neurodevelopmental outcomes) to early copper histidine. These patients have mutations that enable at least some residual copper transport to the developing brain. Consequently, we are developing alternative therapeutic approaches, including intracerebroventricular copper administration, that bypass the blood-brain barrier. To assess safety and determine a maximum tolerated dose (MTD) of copper histidine, we began an animal protocol of intracerebroventricular copper histidine administration in adult male rats and established a maximum tolerated dose of 0.5 ?g. These studies found no statistically significant differences in behavior, growth or brain histopathology between animals receiving the MTD of copper histidine and saline-treated controls. These findings are relevant to determining a suitable intracerebroventricular dose for human administration in selected Menkes disease patients.