As of March 25, 2022 6:15 pm Central European Time, Global has reported 476374234 confirmed cases of COVID-19 , including 6108976 deaths . There are 873,944 confirmed cases of new coronavirus infection in China, and 12,261 people died of due to new coronavirus infection.
Figure 1 Globally reported WHO Number of new coronavirus infection cases and deaths
The potential sequelae of new coronavirus infection has attracted widespread attention, especially the impact on nervous system . Recently, a study published by the University of Oxford in the UK in the journal " Nature " showed that the new coronavirus may cause brain atrophy .
Source: Weibo screenshot
How does the new coronavirus affect the nervous system? Will the brains of mild or asymptomatic patients also be affected? Below is the popular science time.
The new coronavirus accelerates brain atrophy?
SARS-CoV-2 (new coronavirus) severely infected patients with fever, dry cough, dyspnea , pneumonia , etc. At the same time, gastrointestinal tract symptoms and cardiovascular system dysfunction will also occur. In addition, reports of nervous system and psychiatric symptoms continue to emerge in infected patients.
Loss of taste and smell is a commonly reported early symptoms, and there are also some clinically reported complications caused by infection such as headache, nausea, vomiting, impaired consciousness, encephalitis and acute cerebrovascular diseases (stroke, venous sinus thrombosis and cerebral hemorrhage ) [1].
How does the new coronavirus infect the nervous system?
The novel coronavirus attaches to central nervous system cells through the interaction of spike (S) glycoprotein with the host ACE2 receptor (angiotensin-converting enzyme 2 transmembrane receptor), which is present in neurons and endothelial cells .
Existing research data shows that there are three potential possible ways for the new coronavirus to infect the central nervous system of : spreads to other brain regions through olfactory nerve and/or sublingual nerve, facial nerve, glossopharyngeal nerve and vagus nerve to other brain regions . The symptoms are early symptoms of olfactory and taste.
passes the blood-borne pathway of endothelial infection, utilizes the ACE2 receptor in endothelial cells, and then enters the blood-brain barrier through virus budding through interaction with the ACE2 receptor in neurons. With the help of immune cells, the new coronavirus can infect the central nervous system. The virus first infects the trachea, bronchial and alveolar epithelial cells, and then infects tissue-resident immune cells that carry the virus to other organs, including the brain [1].
Nervous manifestations of patients with COVID-19 (pneumonia infected by novel coronavirus)[1]:
- Difficult, headache, nausea, impaired consciousness (nonspecific neurological symptoms)
- Decreased taste, decreased smell,
- Celebrovascular accident (infarction, cerebral hemorrhage, Venous thrombosis )
- Acute necrotic brain Disease
- meningitis
- Green-Barre syndrome
- Myalgia, creatine kinase and Lactate dehydrogenase (characteristics of nonspecific muscle disease)
- Anxiety, depression, insomnia, pain, and mental disorder (nonspecific mental symptoms)
Figure 2 The results of anatomical study on the pathological section of hindbrain
new coronary severe death anatomy showed the activities of T cells and microglia in the frontal and frontal lobe areas of the brain (Figure 2). SARS-CoV-2 infection causes inflammatory cellular responses in the patient's brain.
Recently, the number of asymptomatic infections in has increased. Will it also be affected?
The following symptoms may occur after the new coronavirus infects the central nervous system:
(1) Ischemia/hypoxia encephalopathy
(2) Activated microglia and variable perivascular T lymphocytes infiltration increased
(3) Cerebrovascular disease, hemorrhagic infarction, ischemic infarction, cerebral hemorrhage acute multiple necrotic encephalopathy
(3) Cerebrovascular disease, hemorrhagic infarction, ischemic infarction, cerebral hemorrhage acute multiple necrotic encephalopathy
(4) Opportunistic infection
(5) Encephalitis/meningitis
(6) Acute myelitis
(7) Green-Barre syndrome
(8) Demyelination disease
and mild and asymptomatic infection patients did not progress to the central nervous system infection stage or timely treatment and recovery.
What changes will happen to the brain before and after the infection with the new coronavirus?
There are also public information reports that the new coronavirus infects the central nervous system and triggers the development of autoimmune brain diseases. SARS-CoV-2 enters the central nervous system (CNS) to activate microglia, causing chronic neuroinflammation and possible neurodegeneration. The complex transcriptome of SARS-CoV-2 has molecular similarities with a variety of human CNS protein epitopes, leading to the production of cytokine storm and various autoantibodies , and the occurrence and development of autoimmune brain diseases may occur [2]. In addition to being highly expressed in respiratory, digestive and excretion systems cells, is also significantly higher than other tissues and organs in (Figure 3) [3]. This has also attracted widespread attention to the impact of SARS-CoV-2 on human reproduction.
Figure 3 Relative expression of ACE2 receptor in different tissue cells
faces this wave of epidemic, how to prevent it?
New antigen detection is a supplementary detection method for new coronavirus nucleic acid detection , and can be selected according to your own detection needs. The prevention of the new crown epidemic is daily. After actively vaccinating the new crown vaccine, it is still necessary to wear masks in a standardized manner to reduce the number of people entering and leaving the crowded and complex places.
References:
[1].Al-Sarraj, S., C. Troakes, B. Hanley, M. Osborn, et al., Invited Review: The spectrum ofneuropathology in COVID-19. Neuropathol Appl Neurobiol, 2021. 47(1): p. 3-16.
[2].Gupta, M. and D.F. Weaver, COVID-19 as a Trigger of Brain Autoimmunity. ACS Chem Neurosci, 2021. 12(14): p. 2558-2561.
Source: Popular Science China, this article expert: Yang Jing, Ph.D. in Immunology, vaccine popular science author (viral vaccine research and development, vaccine clinical research direction), copyright belongs to the original author. If there is any infringement, please contact us to delete
