研究：新冠病毒有可能感染人脑 | 双语阅读
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美国科学家发现新冠病毒可以感染人脑并在人脑细胞内复制的直接证据。
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全文共415个词，By Clive Cookson
US scientists have found the first direct evidence that coronavirus could infect the human brain and replicate inside its cells, heightening concern about the disease’s poorly understood neurological symptoms.
美国科学家发现了新型冠状病毒可以感染人脑、并在人脑细胞内复制的首个直接证据，这加剧了有关这种疾病会导致神经系统症状的担忧，目前科学家对这方面了解不多。
Thomas Hartung and colleagues at Johns Hopkins University made the discovery after adding low levels of Sars-Cov-2, the virus responsible for Covid-19, to tiny neuronal balls known as mini-brains that are grown from human stem cells.
约翰•霍普金斯大学(Johns Hopkins University)的托马斯•哈通(Thomas Hartung)及同事将低水平的Sars-Cov-2——导致新型冠状病毒肺炎（COVID-19，即2019冠状病毒病）的病毒——添加至用人类干细胞培育的微小神经元球，即“迷你大脑”，获得了上述发现。
The researchers found the virus infected neurons in the mini-brains via the ACE2 human protein that is known to be an important entry point for Sars-Cov-2. The virus then multiplied within the neurons; within three days the number of copies had increased at least tenfold.
研究人员发现，病毒通过人类ACE2蛋白——已知的Sars-Cov-2进入人体细胞的重要入口——感染了迷你大脑中的神经元。病毒随后在神经元内繁殖；复制的病毒数量在三天内增加了至少十倍。
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“It is really critical to know that our most precious organ can be directly affected by the virus,” said Prof Hartung, a toxicology expert at Johns Hopkins, adding it was still unclear how frequently this happened in Covid-19 patients.
“知道我们最宝贵的器官可能直接受到这种病毒的影响是至关重要的，”身为约翰霍普金斯大学毒理学专家的哈通教授表示。他补充说，尚不清楚有多大比例的COVID-19患者大脑受到感染。
Whether the virus can infect the brain is among the biggest questions in a long list of unknowns about the way the disease seems to affect most tissues and organs in the human body.
在关于该疾病似乎影响人体多数组织和器官的方式的冗长问题清单上，病毒会不会感染人脑是最大问题之一。
The study, which is under peer review at the journal Altex but not yet published, follows unconfirmed reports of neurological symptoms in Covid-19 patients, including in the original outbreak in Wuhan. More than a third of coronavirus victims who were hospitalised in the Chinese city exhibited neurological symptoms, including dizziness, headache and seizures.
这项研究正在接受《Altex》期刊的同行评议，但尚未发表。此前有未经证实的报道称，一些COVID-19患者出现神经系统症状，包括在疫情最早爆发地武汉。在这座中国城市住院的新冠病毒受害者中，有三分之一以上表现出神经系统症状，包括头晕、头痛和癫痫发作。
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However, it has never been clear whether the virus affects the brain and nerve cells directly or whether such symptoms are a secondary result caused by damage to the patients’ immune and cardiovascular systems.
然而，科学家从未搞清楚的是，这种病毒是直接影响大脑和神经细胞，抑或这些症状是患者免疫和心血管系统受损引起的继发性结果。
For instance, it is not known whether a loss of the sense of smell, a common symptom of the virus, is a result of direct infection of olfactory neurons or a side-effect of infection in other cells involved in olfaction.
例如，尚不清楚嗅觉丧失（新冠病毒的常见症状）是嗅觉神经元直接受到感染的结果，抑或是涉及嗅觉的其他细胞受到感染的副作用。
If Sars-Cov-2 can attack the human brain, it has to get past the blood-brain barrier that shields the organ against many viruses and chemicals and often prevents infections.
如果Sars-Cov-2可以攻击人脑，那么它必须越过血脑屏障；这道屏障使大脑免受许多病毒和化学物质的侵害，往往能够防止感染。
Although the Johns Hopkins mini-brains show some features of a human brain, including electrical activity and communications between neurons, they lack other features, including the blood-brain barrier.
尽管约翰霍普金斯大学的迷你大脑显示人脑的某些特征，包括电活动和神经元之间的通讯，但它们缺乏其他特征，包括血脑屏障。
“Whether or not the Sars-Cov-2 virus passes this barrier has yet to be shown,” Prof Hartung said, “but it is known that severe inflammations, such as observed in Covid-19 patients, make the barrier disintegrate.”
“Sars-Cov-2病毒能否通过血脑屏障尚待证实，”哈通教授表示，“但已经知道的是，在COVID-19患者身上观察到的那种严重炎症，会使这道屏障瓦解。”
The mini-brains, known as BrainSpheres, were developed four years ago and are mass-produced as standardised organoids for toxicology testing of drugs. They have been used to study the effect of other viruses on the brain, including Zika, dengue and HIV.
被称为BrainSpheres的这些迷你大脑是四年前开发的，目前批量生产，作为标准化的类器官用于药物毒理学试验。它们已被用于研究其他病毒对大脑的影响，包括寨卡病毒(Zika)、登革热和艾滋病毒(HIV)。
One particular concern highlighted by Prof Hartung was over the possible effects of the virus on the foetal brain during pregnancy. Other research has shown the virus crosses the placenta and that embryos lack the blood-brain barrier during early development.
哈通教授特别指出的一个担忧是这种病毒在孕期对胎儿大脑的可能影响。其他研究已表明，这种病毒可以穿过胎盘，而胎儿在早期发育阶段没有血脑屏障。
“To be very clear, we have no evidence that the virus produces developmental disorders,” Prof Hartung emphasised. “But clinicians need to know about this research, because it has consequences about [being] cautious and preventing infection during pregnancy.”
“必须明确的是，我们没有证据表明该病毒会导致发育障碍，”哈通教授强调说。“但是临床医生需要了解这项研究，因为它对于在怀孕期间保持谨慎和预防感染是有影响的。”
The research has significant implications for attempts to find treatments for the virus. If Sars-Cov-2 does infect the brain, it may complicate efforts to eradicate the infection through drugs, because many medicines cannot get past the blood-brain barrier.
这项研究对于寻找该病毒的治疗方法具有重大潜在影响。如果Sars-Cov-2确实会感染人脑，这可能会使通过药物根除这种传染病的努力变得复杂，因为许多药物无法通过血脑屏障。
本文6月16日发布于FT中文网，英文原题为Coronavirus could infect human brain and replicate, US study shows
