OXIDATIVE, ANTIOXIDANT AND TRACE ELEMENT STUDIES IN THE ALZHEIMER'S BRAIN

阿尔茨海默病(AD)是老年人的主要健康问题之一 老年人，折磨着400万美国人。取得进展的主要障碍 在预防或治疗阿尔茨海默病方面缺乏对 疾病的发病机制/病因学。自由基在AD中的作用 已经提出，但只有最少的证据支持。基本假设 在这项提案中要测试的是a)氧化应激增加 在AD和b)脑中，铁(Fe)和其他微量元素含量升高 催化活性氧物种(ROS)的形成，促进氧化 生物分子的改变，这在糖尿病的发病机制中发挥了作用 神经元变性AD。我们之前的研究表明：a)海拔升高 阿尔茨海默病不同脑区的铝、铁、汞和硅，b)增加 衰老和阿尔茨海默病患者大脑中的蛋白质氧化和 阿尔茨海默病中的氧化敏感酶，以及c)脂质增加 内侧颞叶结构中的过氧化和抗氧化活性 在公元后。这项研究旨在解决我们在认识上的主要差距 自由基在阿尔茨海默病中的作用：a)量化血脂水平 过氧化，(丙二醛、4-羟基壬烯醛和C3-C10醛) 高效液相色谱)、多不饱和脂肪酸(高效液相色谱)、蛋白质氧化(蛋白质 和DNA氧化(GC-MS-SIM)；b)对活性进行定量 和信使RNA水平(Northern Blots)和蛋白质分析(Western 超氧化物歧化酶、谷胱甘肽过氧化物酶、谷胱甘肽 还原酶和过氧化氢酶；c)谷氨酰胺活性的测定 合成酶和肌酸激酶，氧化敏感酶；d) 仪器法测定铝、铜、铁、汞、硒、锌的含量 激光中子活化分析和石墨炉原子吸收光谱与细胞水平 微探针质谱仪和e)定量形态改变 (淀粉样蛋白负荷、神经原纤维缠结、神经元和突触密度) 计算机图像分析，全部在4个新皮质区域，海马区， 死后短时间杏仁核、Meynert基底核和小脑 间隔尸检AD和年龄匹配的对照组。这些研究将是 在紧邻的组织节段上执行以允许相关 这些参数中。此外，铁和铜对ROS的影响 这些脑区突触体膜组分的形成 将使用电子顺磁共振进行。要定义 神经元退行性变的可能机制、铁等的影响 微量元素对ROS形成、神经元存活和抗氧化酶的影响 将进行海马神经元体外活性的研究。本研究 将有助于更好地了解其中一种拟议的致病原因 阿尔茨海默病神经元退变机制的研究 未来可能对这种疾病进行治疗干预。

Alzheimer's disease (AD), one of the major health problems of the elderly, afflicting 4 million Americans. The major barrier to progress in preventing or treating AD is a lack of understanding of the pathogenesis/etiology of the disease. A role for free radicals in AD has been proposed but is supported by minimal evidence. The basic hypotheses to be tested in this proposal are a) there is increased oxidative stress in the brain in AD and b) elevated iron (Fe) and other trace elements catalyze reactive oxygen species (ROS) formation, enhancing oxidative alterations in biomolecules, which play a role in the pathogenesis of neuron degeneration AD. Our previous studies showed a) an elevation of Al, Fe, Hg, and Si in various brain regions in AD, b) an increase in protein oxidation in the brain in aging and AD and a decline in oxidative-sensitive enzymes in AD, and c) an increase in lipid peroxidation and antioxidant activity in medial temporal lobe structures in AD. This study is designed to address major gaps in our understanding of the role of free radicals in AD by a) quantitating the levels of lipid peroxidation, (malondialdehyde, 4-hydroxynonenal and C3-C10 aldehydes by HPLC), polyunsaturated fatty acids (by HPLC), protein oxidation (protein carbonyl), and DNA oxidation by (GC-MS-SIM); b) quantitating the activity and messenger RNA levels (Northern blots) and protein analysis (Western blots) of superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase; c) determining the activity of glutamine synthetase and creatine kinase, oxidative-sensitive enzymes; d) quantitating bulk levels of Al, Cu, Fe, Hg, Se and Zn by instrumental neutron activation analysis and GFAAS and the cellular level by laser microprobe mass spectrometry and e) quantitating morphologic alterations (amyloid burden, neurofibrillary tangles, neuron and synapse density) by computerized image analysis, all in 4 neocortical regions, hippocampus, amygdala, nucleus basalis of Meynert and cerebellum of short postmortem interval autopsied AD and age-matched controls. These studies will be performed on immediately adjacent tissue segments to allow correlation of these parameters. In addition, the effect of Fe and Cu on ROS formation in synaptosomal membrane fractions from these brain regions will be performed using electron paramagnetic resonance. To define possible mechanisms of neuron degeneration, the effect of Fe and other trace elements on ROS formation, neuron survival and antioxidant enzyme activity in hippocampal neurons in vitro will be performed. This study will lead to a better understanding of one of the proposed pathogenetic mechanisms of neuron degeneration in AD and form a foundation for potential future therapeutic intervention in this disorder.