患有艾滋病痴呆后大脑不能修复
The brain cannot regenerate in HIV-associated dementia
HIV 'launches two-pronged attack on brain'
[BEIJING] Scientists have identified a way that HIV causes dementia, which could help in developing drugs to treat the disorder.
The study was published this week (16 August) in the journal Cell Stem Cell.
HIV infection can cause difficulties in memory and learning in patients with advanced disease, a condition known as HIV-associated dementia.
Anti-retroviral drugs are not entirely effective in protecting patients from developing the condition because the drugs cannot successfully reach the brain.
'The brain therefore is a protected reservoir of HIV,' says Stuart Lipton from the California-based Burnham Institute for Medical Research.
Lipton and colleagues found that besides killing neural cells, the HIV virus also inhibits the ability of brain cells to regenerate.
Using mice, Lipton and colleagues found that a viral protein called HIV/gp120 prevents 'unprogrammed' brain cells ― stem cells ― called adult neural progenitor cells, from developing into new brain cells, thus preventing the brain from repairing itself.
The viral protein does this by activating a brain enzyme ― p38 MAPK ― that blocks brain stem cells from dividing.
Lipton said that a drug that blocks this enzyme could have potential for treating and preventing HIV-associated dementia.
Lu Hongzhou, deputy director of Shanghai Public Health Centre, says now that the Chinese government offers free anti-retroviral treatment to AIDS patients, they live longer and the problem of HIV-associated dementia has become more apparent.
'Previously, many doctors were not aware of the HIV-associated dementia disease, and now, with these kind of studies, doctors can better understand the mechanism of the disease,' Lu told SciDev.Net.
Liu Zhe, director of the Nerve Signal Imitation Laboratory at the Beijing Institute for Psychological Medicine, adds that the study might be used by doctors to distinguish different kinds of dementia and to understand the degree of neural diseases.
'But there is a long way before it could be put into clinical practice,' Liu told SciDev.Net.
艾滋病毒“对大脑发起双重攻击”
[北京]科学家发现了艾滋病病毒导致痴呆症的方式，这可能有助于开发治疗这种精神系统紊乱疾病的新药。这项研究发表在了8月16日出版的《细胞·干细胞》杂志上。
艾滋病感染能够引发晚期患者的记忆力和学习困难，这种状况称为艾滋病痴呆。
目前治疗艾滋病的抗逆转录病毒药物并不能完全有效的保护病人不发生艾滋病痴呆，因为这类药物很难进入大脑。美国加州Burnham医学研究所的Stuart Lipton说：“大脑因此成为了艾滋病毒的受保护的存贮区。”
Lipton及其同事发现，除了杀死神经细胞外，艾滋病毒还能抑制大脑细胞再生的能力。Lipton和同事用小鼠发现了一个名为HIV/gp120的艾滋病病毒蛋白阻止了名为成年神经前体细胞（adult neural progenitor cells）的大脑干细胞分化成新的脑细胞，从而让大脑无法修复自己。
病毒蛋白通过激活大脑的一个酶——p38 MAPK——来阻止大脑干细胞分化。Lipton说，一种抑制这种酶的药物有可能治疗和预防艾滋病痴呆。
上海公共卫生中心的副主任卢洪洲表示，随着中国政府为艾滋病患者提供免费的抗逆转录病毒药物，他们的存活期更长了，艾滋病痴呆的问题因而也更加明显。
“过去，许多医生意识不到艾滋病痴呆症，现在，通过这类研究，医生们能更好地理解这种疾病的机理，” 卢洪洲告诉本网络记者。
北京心理医学研究所神经导丛实验室主任刘喆补充说，这一研究可以被医生们用来识别不同种类的痴呆症，并更好地理解神经病变的程度。
但是他告诉本网络，“要把这一研究能投入临床实践还有很长一段路要走。”
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