VOA健康报道2022--新冠病毒感染引发的免疫反应会损害大脑的血管

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Study: Immune Response Caused by COVID May Damage Brain

A small study from the U.S. National Institutes of Health says the immune response caused by COVID-19 infection may damage the brain's blood vessels². The reaction could lead to neurological problems known as long COVID.

In the study, researchers examined brain changes in nine people who died suddenly after being infected with SARS-CoV-2, the virus that causes COVID-19. The results appeared last week in the publication Brain.

Damage to the brain's blood vessels

The researchers found that antibodies — proteins produced by the immune system to fight viruses — are involved in an attack on the cells lining³ the brain's blood vessels. This causes inflammation and damage.

The results were similar to an earlier study done in 2020.

In both studies, SARS-CoV-2 was not found in the patients' brains. This suggests the virus was not attacking the brain directly.

NIH scientist Avindra Nath is the senior researcher of the study. He said, "We had previously⁴ shown blood vessel¹ damage and inflammation in patients' brains at autopsy⁵, but we didn't understand the cause of the damage." An autopsy is the examination of a dead body to find out the cause of death.

For the study, Dr. Nath and a team of researchers examined brain tissue from nine individuals between the ages of 24 and 73. The individuals were chosen because their scans showed signs of blood vessel damage in the brain. The scans were then compared to those from 10 individuals in a control group.

The researchers found that antibodies produced to fight COVID-19 may mistakenly target cells that line the brain's blood vessels. These cells, called endothelial cells, serve as barriers to keep harmful substances from reaching the brain. Damage to the cells causes bleeding and blockage⁶ in some COVID-19 patients and increases the risk of stroke.

As in their earlier study, researchers found signs of leaky blood vessels. This suggests that the links between endothelial cells in the blood-brain barrier were damaged.

Dr. Nath said that once the leaks happened, immune cells "may come to repair the damage, setting up inflammation" in the brain.

Long-term neurological symptoms

Researchers also found changes in gene⁷ expression in areas with damage to the endothelial cells. More than 300 genes⁸ showed decreased expression, while six genes showed increased expression. The affected⁹ genes are connected to the brain's ability to deal with chemical imbalances in the body.

Together, these findings may provide information about the cause of neurological problems related to COVID-19. The findings may also be used to find new treatments to target the damaged links between the endothelial cells in the blood-brain barrier.

The study may also help with understanding and treating long-term neurological conditions after COVID-19. The conditions include headache, tiredness, loss of taste and smell, sleep problems, and forgetfulness known as "brain fog."

If the nine patients in the study had survived, the researchers believe they would have likely developed long COVID.

"It is quite possible that this same immune response persists in long COVID patients," Dr. Nath said. The findings, he added, are "very important" to researchers seeking to find treatments for long COVID.

Words in This Story

response - n. something that is done as a reaction to something

neurological - adj. related to the study of the nervous system and the diseases that affect it

vessel - n. a vein¹⁰ or artery¹¹ that carries blood through the body

inflammation - n. a condition in which part of the body becomes swollen¹² and painful

stroke - n. a serious illness caused when a blood vessel in the brain is broken or blocked

persist - v. to continue to exist beyond the expected time

1 vessel   

n.船舶；容器，器皿；管，导管，血管

参考例句：

• The vessel is fully loaded with cargo for Shanghai.这艘船满载货物驶往上海。
• You should put the water into a vessel.你应该把水装入容器中。

2 vessels   

n.血管( vessel的名词复数 )；船；容器；（具有特殊品质或接受特殊品质的）人

参考例句：

• The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
• All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》

3 lining   

n.衬里，衬料

参考例句：

• The lining of my coat is torn.我的外套衬里破了。
• Moss makes an attractive lining to wire baskets.用苔藓垫在铁丝篮里很漂亮。

4 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

5 autopsy   

n.尸体解剖；尸检

参考例句：

• They're carrying out an autopsy on the victim.他们正在给受害者验尸。
• A hemorrhagic gut was the predominant lesion at autopsy.尸检的主要发现是肠出血。

6 blockage   

n.障碍物；封锁

参考例句：

• The logical treatment is to remove this blockage.合理的治疗方法就是清除堵塞物。
• If the blockage worked,they could retreat with dignity.如果封锁发生作用，他们可以体面地撤退。

7 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

8 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

9 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

10 vein   

n.血管，静脉；叶脉，纹理；情绪；vt.使成脉络

参考例句：

• The girl is not in the vein for singing today.那女孩今天没有心情唱歌。
• The doctor injects glucose into the patient's vein.医生把葡萄糖注射入病人的静脉。

11 artery   

n.干线，要道；动脉

参考例句：

• We couldn't feel the changes in the blood pressure within the artery.我们无法感觉到动脉血管内血压的变化。
• The aorta is the largest artery in the body.主动脉是人体中的最大动脉。

12 swollen   

adj.肿大的，水涨的；v.使变大，肿胀

参考例句：

• Her legs had got swollen from standing up all day.因为整天站着，她的双腿已经肿了。
• A mosquito had bitten her and her arm had swollen up.蚊子叮了她，她的手臂肿起来了。