新的研究揭示了Covid-19如何进入大脑

一年多到Covid-19大流行,研究rchers are still learning about the disease and its impact on the body. Although it is primarily classified as a respiratory virus, scientists now know that Covid-19 can impact other body systems to cause a variety of effects—including neurological symptoms.

New研究来自路易斯安那州立大学的实验生物学2021年，是美国生理社会的年度会议。调查结果表明，其中一些症状包括认知，流动性和感官经验的变化 - 可能归因于病毒在大脑和脊髓中的存在，在一起central nervous system，负责处理和响应感官输入的身体系统。

These new findings could later inform preventative care and approaches to recovery and treatments, but those who have recovered from the illness could still have a long road ahead. Many who live with "long-haul" neurological symptoms are learning to live with more persistent changes in function and mobility or senses and perception.

How Does Covid-19 Attack the Central Nervous System?

里卡多科斯塔博士和戴安娜Cruz-Topete卢isiana State University have been investigating how Covid-19 enters the central nervous system. There are multiple pathways the virus takes to reach the brain and spinal cord, and their research demonstrates that one route is through theblood-brain barrier--a semi-permeable border that selectively allows nutrients to flow to and from the brain.

存在血脑屏障，以防止血液中存在的任何病原体和毒素到达大脑以阻止疾病或疾病的传播。在血脑屏障中，glial cellssupport宿司and take on the role of protecting and defending the brain and neurons. A sub-type of glial cells,astrocytes, are the most abundant glial cells in the central nervous system and the brain.

In the respiratory system, the Covid-19 virus grabs hold of a specific protein on the surface of each cell. This research team discovered that brain cells have also this protein, which experts hadn't previously confirmed.

Astrocytes, which defend the blood-brain barrier and神经元从感染，比神经元更耐粘性-19，细胞接收感觉输入并从大脑发送到身体的其他部位。但它只需要一些受感染的星形胶质细胞来将病毒传播到相邻的神经元。

Costa says that astrocytes are infected within a few days of exposure and the team has yet to determine how long it takes for the infection to spread to neurons, but because neurons are more susceptible to infection, the virus is likely to spread more rapidly once it reaches them.

病毒依赖于它们感染的细胞的支持率。一旦感染神经元和星形胶质细胞，Covid-19病毒就会复制细胞的遗传物质，模仿其物理和化学成分以欺骗邻近的细胞以感染它们。这继续感染的传播 - 病毒在呼吸系统中重复的方式相同。

什么神经系统症状可以covid-19原因？

神经元在身体内部通信系统中发挥着重要作用。作为其作用捍卫血脑屏障的作用的一部分，星形胶质细胞通过帮助向其预期目标引导信息来支持神经元，支持神经元之间的通信和调节大脑中的炎症。这些过程中的每一个有助于保持神经元的最佳环境，以适当地发出信号和功能。

如果神经元不适当运作，则可能出现神经系统挑战。对于Covid-19患者，神经系统症状倾向于包括肌肉疼痛和痛苦，头痛，混乱和迷失方向，头晕和感官经验的变化 - 例如味道或气味。

Strokes, changes in movement and motor function as well as perception, and seizures have also been reported, but these experiences are less common.

长途或后咖啡后的条件是一系列症状 - 许多神经系统 - 患者因Covid-19感染而经历的经历，这些感染是正在进行或经常返回的。据CDC称, symptoms are considered part of a post-Covid condition if health problems persist for longer than four weeks following the initial infection.

Related:Separating Myth from Face with Gwenyth Paltrow's Long-Haul Covid Reveal

患者如何知道病毒是否已达到中枢神经系统？

Patients should monitor disease progression to look out for neurological symptoms they didn't have before they were diagnosed with Covid-19. New symptoms are likely linked with infection.

哥斯达表示，有些人可能会更大的风险，解释，“血脑屏障通常受到损害的多种硬化等疾病。这可能使中枢神经系统更容易受病毒感染的影响。”

Costa says that it's unclear how long the virus stays active within the central nervous system, but that the virus may change the way cells behave for a considerable amount of time, causing inflammatory factors that counteract health and harm cells. This could lead to longer recovery times or long-haul experiences.

The central nervous system, while at risk, will not always become infected if someone contracts Covid-19. Some neurological symptoms might not even be caused by the infection reaching the brain and spinal cord. Instead, it could be inflammation.

If someone who has contracted Covid-19 loses the sense of taste or smell, for instance, it could be because neurons are infected, impacting the way the sensory messages are sent and received t. Or it could be due tosystemic inflammation, which impacts the brain without ever infecting it. Currently, more research is needed to know which of these two possible causes is leading to neurological symptoms in individual patients.

新发现如何影响预防和恢复

Because astrocytes are more resistant to infection, Costa says these cells could play a key role in developing protective measures for the central nervous system. Researchers explain that astrocytes are known to be impacted by other viruses, including HIV, and cautiously explain that this new data is just one preliminary part of the puzzle.

鉴于如何在Covid-19患者中可以治疗神经系统症状的方式影响，这项研究将如何影响。

Experts have yet to determine if it's more difficult to recover from these neurological symptoms than the respiratory effects of the illness. They note that more evidence is needed to understand the best options for preventative therapies and treatment.

For now, Costa explains that some patients respond well tosteroid treatment. This group of medications mimic the hormone cortisol to rapidly reduce inflammation during overproduction.

Costa says that it's not clear if current vaccines will help to protect those who encounter the virus from neurological symptoms or prevent the infection from spreading to the central nervous system, but Cruz-Topete hopes that clinical data from ongoing trials will provide more clarity.