阿尔茨海默病与雌激素缺失有关？

脑中下降的雌激素与女性的阿尔茨海默病（老年原发性退化性痴呆）相关！！

在亚利桑那州一个研究所的研究报告中指出：通过对患有阿尔茨海默病的患者的尸检,发现女性AD病人与没有患AD相似女性的脑中有明显少的雌激素含量。

这个发现有助于解释为何在女性中AD的高流行性。动物试验显示脑中雌激素缺失加速了脑"plaque" 形成，而这个结构则是AD病的特征性病变。

血中雌激素分析并不支持这个发现，因为血中的雌激素无论在AD患者，还是普通人中，都很低。芝加哥（美国中西部一大城市）大学的医学院Rena Li博士在国家科学院学院学报中报道。

Rena Li博士在路透社健康栏目中说：“脑中的雌激素缺失比血中雌激素缺失更具有特殊意义”，在AD的形成过程中，“这是个关键性的发现”－－－脑自身不能制造雌激素。

为检验脑组织中这个发现与严重的AD发生之间的相关性，博士Rena Li小组的人进行动物试验，通过用雌激降解酶使带有AD plaque蛋白结构的老鼠缺失雌激素等方法中来试验。

试验结果：这些动物很大程度上降低了脑中雌激素水平，并且很早就出现了plaque结构出现。经过对照，去除子宫的老鼠并没有出现脑中雌激素缺失疾病。

她说：对AD有意义的治疗是用雌激素，并要注意血脑屏障这个问题。

http://jerrydoctor.net

Low brain estrogen linked to Alzheimer's in women

NEW YORK (Reuters Health)

    Post-mortem studies of the brains of women with Alzheimer's disease (AD) show a much lower estrogen content than similar women without the disorder, researchers report.

    The findings may help explain the higher prevalence of AD in women than men, since animal experiments show brain estrogen deficiency accelerates the brain "plaque" build-up that characterizes the disease.

     Blood estrogen analysis did not support the brain tissue findings, since serum estrogen was low in both the AD patients and normal subjects, Dr. Rena Li and colleagues at the University of Chicago note in the Proceedings of the National Academy of Sciences.

     Li told Reuters Health that "brain estrogen deficiency is more specific than blood estrogen deficiency" in the development of AD. "That is the key finding -- the brain can't manufacture estrogen."

      To examine the correlation between brain tissue findings and the onset and severity of AD, Li's team conducted animal studies in which they crossed mice lacking an estrogen-synthesizing enzyme with mice carrying a protein related to AD plaque build-up.

      The resulting animals had greatly reduced brain estrogen levels and early onset plaque formation. By contrast, mice that underwent ovary removal did not develop estrogen-deficient brain disease.

     Li said the findings in these "ovariectomized" mice support the fact that not all post-menopausal women develop AD. "It is brain-specific...and may have a genetic basis," she explained.

     She said potential treatment of AD with estrogen therapy would require drug formulations that cross the tissue barrier that separates blood from the brain. Her team is currently screening a number of natural estrogen products to assess their ability to cross this barrier.

SOURCE: Proceedings of the National Academy of Sciences, December 19, 2005.

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