※ 引述《wizardfizban (疯法师)》之铭言：
: 1.媒体来源:
: Heho健康
: 2.记者署名:
: 林 以璿
: 3.完整新闻标题:
: COVID 19／康复者复阳、恶化原因找到了？研究：新冠病毒可藏匿于大脑
: 4.完整新闻内文:
: 新冠康复者的后续问题引人关注，不只是这些人可能会出现无法恢复的副作用，甚至在全
: 球范围内都有案例复发的问题。近日研究指出，新冠病毒在动物实验中可以藏匿于大脑，
: 成为复发的线索之一。
: 大脑是人类的中央处理器，而COVID-19可引起人类神经系统疾病。近日，《Viruses》发
: 表了研究，发现新冠鼻内感染的小鼠会引起严重的神经系统疾病。
: 鼻腔通往大脑的路径比嘴巴更直接，且嗅觉和味觉的改变是COVID-19的症状之一。因此，
: 研究人员在小鼠鼻腔内接种病毒细胞和PBS，感染的小鼠在第4天开始体重明显减轻，并伴
: 有嗜睡、动作缓慢、共济失调、呼吸困难等并发症，第6天小鼠全部死亡。
: 随后研究人员展开分析，发现，在小鼠肺部和鼻腔的病毒量于第3天达到峰值，在第5天和
: 第6天逐渐下降，而大脑中的病毒在第3天才被检测到，于第5天达到较高巅峰，且脑中的
: 最高病毒滴度比肺中的最高滴度高约1000倍，表明新冠在脑中具有很高的复制潜力。
: 在小鼠感染病毒的第6天，研究人员从大脑包括皮质、小脑和海马回的部位检测到了与细
: 胞相关的病毒抗原，小鼠的神经元缩小并出现退化现象，血管周围出血，白血球浸润增强
: 。这一发现恰好解释了为何某些COVID-19患者的肺功能已经得到改善，但却有可能迅速复
: 发并死亡。
: 由于大脑中不存在免疫反应，因此变成了病毒最喜欢藏身之地。尽管COVID-19康复患者似
: 乎已经逃离魔掌，但依旧可能面临包括自身免疫性疾病、帕金森氏病、多发性硬化症和一
: 般性认知能力下降等健康问题。
: 参考资料：Neuroinvasion and Encephalitis Following Intranasal Inoculation of
: SARS-CoV-2 in K18-hACE2 Mice
: 文/林以璿 图/林以璿
: 5.完整新闻连结 (或短网址):
: https://heho.com.tw/archives/159394
: 6.备注:
: 所以会躲在脑部的意思。
https://reurl.cc/E2nxd0
这似乎是美国卫生研究院NIH某位研究员的BLOG
资讯还蛮新的
Taking a Closer Look at COVID-19’s Effects on the Brain
Posted on January 14th, 2021 by Dr. Francis Collins
While primarily a respiratory disease, COVID-19 can also lead to neurological
problems. The first of these symptoms might be the loss of smell and taste,
while some people also may later battle headaches, debilitating fatigue, and
trouble thinking clearly, sometimes referred to as “brain fog.” All of
these symptoms have researchers wondering how exactly the coronavirus that
causes COVID-19, SARS-CoV-2, affects the human brain.
In search of clues, researchers at NIH’s National Institute of Neurological
Disorders and Stroke (NINDS) have now conducted the first in-depth
examinations of human brain tissue samples from people who died after
contracting COVID-19. Their findings, published in the New England Journal of
Medicine, suggest that COVID-19’s many neurological symptoms are likely
explained by the body’s widespread inflammatory response to infection and
associated blood vessel injury—not by infection of the brain tissue itself
[1].
The NIH team, led by Avindra Nath, used a high-powered magnetic resonance
imaging (MRI) scanner (up to 10 times as sensitive as a typical MRI) to
examine postmortem brain tissue from 19 patients. They ranged in age from 5
to 73, and some had preexisting conditions, such as diabetes, obesity, and
cardiovascular disease.
The team focused on the brain’s olfactory bulb that controls our ability to
smell and the brainstem, which regulates breathing and heart rate. Based on
earlier evidence, both areas are thought to be highly susceptible to COVID-19.
Indeed, the MRI images revealed in both regions an unusual number of bright
spots, a sign of inflammation. They also showed dark spots, which indicate
bleeding. A closer look at the bright spots showed that tiny blood vessels in
those areas were thinner than normal and, in some cases, leaked blood
proteins into the brain. This leakage appeared to trigger an immune reaction
that included T cells from the blood and the brain’s scavenging microglia.
The dark spots showed a different pattern, with leaky vessels and clots but
no evidence of an immune reaction.
While those findings are certainly interesting, perhaps equally noteworthy is
what Nath and colleagues didn’t see in those samples. They could find no
evidence in the brain tissue samples that SARS-CoV-2 had invaded the brain
tissue. In fact, several methods to detect genetic material or proteins from
the virus all turned up empty.
The findings are especially intriguing because there has been some suggestion
based on studies in mice that SARS-CoV-2 might cross the blood-brain barrier
and invade the brain. Indeed, a recent report by NIH-funded researchers in
Nature Neuroscience showed that the viral spike protein, when injected into
mice, readily entered the brain along with many other organs [2].
Another recent report in the Journal of Experimental Medicine, which used
mouse and human brain tissue, suggests that SARS-CoV-2 may indeed directly
infect the central nervous system, including the brain [3]. In autopsies of
three people who died from complications of COVID-19, the NIH-supported
researchers detected signs of SARS-CoV-2 in neurons in the brain’s cerebral
cortex. This work was done using the microscopy-based technique of
immunohistochemistry, which uses antibodies to bind to a target, in this
case, the virus’s spike protein. Also last month, in a study published in
the journal Neurobiology of Disease, another NIH-supported team demonstrated
in a series of experiments in cell culture that the SARS-CoV-2 spike protein
could cross a 3D model of the blood-brain barrier and infect the endothelial
cells that line blood vessels in the brain [4].
Clearly, more research is needed, and Nath and colleagues continue to explore
how COVID-19 affects the brain and triggers the neurological symptoms often
seen in people with COVID-19. As we learn more about the many ways COVID-19
wreaks havoc on the body, understanding the neurological symptoms will be
critical in helping people, including the so-called Long Haulers bounce back
from this terrible viral infection.
简单说
1.COVID确实会对病患带来神经系统症状 brain fog
2.神经系统症状原因比较倾向炎症反应导致而非脑组织被感染，即神经元感染受损导致
3.透过MRI发现大脑嗅球与脑干有发炎与出血迹象，但在脑组织中
检测不到病毒的核酸与蛋白质
4.有小鼠研究发现病毒刺突蛋白穿过血脑屏障
5.NIH研究员在尸检研究中，用显微镜在大脑皮质神经元中观察到COVID的体征
这是用抗体结合刺突蛋白的化验技术
6.NIH的细胞培养实验中，发现刺突蛋白可穿透血脑屏障并感染大脑血管中的内皮细胞
心得
病毒可能穿透血脑屏障并感染大脑血管上的细胞甚至是神经元
不过究竟大脑神经元是否会被病毒感染受直接影响
即是否为神经系统症状 brain fog 的原因之一则还需要更进一步的研究