日本研究人员一项最新研究成果显示，向患有阿尔茨海默氏症的实验鼠血管中注射一种基因物质，成功使得负责分解β淀粉样蛋白的基因在脑内发挥作用，实验鼠的病症得到明显改善。这使得将来有可能以接种疫苗的形式来预防这种常见疾病。
一种名为脑啡肽酶的分解酶发挥着防止β淀粉样蛋白蓄积的功能，β淀粉样蛋白的蓄积被认为是导致阿尔茨海默氏症的原因。但随着年龄增长，一些人负责生成脑啡肽酶的基因功能出现衰退，从而导致发病。
日本理化学研究所18日发表公报称，该所研究人员和长崎大学研究人员合作，将脑啡肽酶的基因植入一种无病原性病毒，并将其注射到患病实验鼠血管中。结果显示，这种基因只在实验鼠脑内产生作用，帮助形成脑啡肽酶，在其他器官中并无功用。研究发现，接受注射的实验鼠脑内β淀粉样蛋白比其他患病实验鼠减少约30％，学习和记忆能力也恢复到与正常实验鼠相当的水平。
这种基因注射疗法较一些脑神经疾病的基因疗法更简单易行，甚至将来有可能实现阿尔茨海默氏症的“预防接种”。相关论文已经刊登在英国《科学报告》（Scientific Reports）杂志上。（生物谷Bioon.com）
doi:10.1038/srep01472
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Global brain delivery of neprilysin gene by intravascular administration of AAV vector in mice
Nobuhisa Iwata; Misaki Sekiguchi; Yoshino Hattori; Akane Takahashi; Masashi Asai; Bin Ji; Makoto Higuchi; Matthias Staufenbiel; Shin-ichi Muramatsu; Takaomi C. Saido
Accumulation of amyloid-β peptide (Aβ) in the brain is closely associated with cognitive decline in Alzheimer's disease (AD). Stereotaxic infusion of neprilysin-encoding viral vectors into the hippocampus has been shown to decrease Aβ in AD-model mice, but more efficient and global delivery is necessary to treat the broadly distributed burden in AD. Here we developed an adeno-associated virus (AAV) vector capable of providing neuronal gene expression throughout the brains after peripheral administration. A single intracardiac administration of the vector carrying neprilysin gene in AD-model mice elevated neprilysin activity broadly in the brain, and reduced Aβ oligomers, with concurrent alleviation of abnormal learning and memory function and improvement of amyloid burden. The exogenous neprilysin was localized mainly in endosomes, thereby effectively excluding Aβ oligomers from the brain. AAV vector-mediated gene transfer may provide a therapeutic strategy for neurodegenerative diseases, where global transduction of a therapeutic gene into the brain is necessary.
(责任编辑：zengchang
