Is there a gender difference in COVID-19's infection to humans?
In this epidemic, an interesting topic is whether the gender differences between men and women, as well as the huge differences in human structure and biology, will have different effects on the infection situation in COVID-19.
In earlier papers, researchers have drawn different conclusions about the incidence and mortality of COVID-19 in different gender groups. Some people think that there is no difference, some people think that women are more susceptible to infection, and some people think that the mortality rate of male patients is higher than that of women.
Now, this question has a clearer and more convincing answer.
Meta-analysis of 77932 patients
On March 30th, a research paper titled "Gender Differences in Severity and Mortality of Patients with Coronavirus Pneumonia-19: Evidence from Summary Literature Analysis and Insights from Comprehensive Bioinformatics Analysis" appeared on the pre-printed website ArXiv.
This article was published by Professor Ren Shancheng of Shanghai Changhai Hospital. The authors are Wei, Xiao Yutian, Wang Jian and He.
This paper attempts to explore the gender differences in the severity and mortality of patients with coronavirus pneumonia-19 by collecting evidence from literature analysis and comprehensive bioinformatics analysis.
It can be said that this is the first big data analysis study on the correlation between morbidity/severity/mortality and gender in COVID-19 according to the requirements of meta-analysis and systematic review.
According to BioArtReports' report on papers, *** 156 1 articles (including preprinted articles) were retrieved in this study. After independent screening by many people, 39 studies * * 77932 patients were finally included in the meta-analysis, including 4 15 10 males, accounting for 53.3%.
The results showed that the incidence rate of men in COVID-19 was significantly higher than that of women in 39 overall studies of all cases, and 34 studies from China population supported this conclusion.
At the same time, * * * 2 1 and 8 studies reported the number of severe cases and deaths respectively. The results of meta-analysis show that the severity rate and mortality rate of male population are also significantly higher than that of female population.
Further subgroup analysis also found that there was no significant difference in the proportion of severe patients of different sexes among patients whose average age was less than 50 years old. Among the patients over 50 years old, the severity rate of male patients is significantly higher than that of female patients.
From the above subgroup analysis, it can be seen that the older the patient is, the higher the proportion of serious illness among men than among women, suggesting that medical staff should pay more attention to middle-aged and elderly men in the process of treating COVID-19 patients.
On the whole, the article thinks that the incidence, severity and mortality of novel coronavirus in male population are higher than those in female population.
Biological causes of differences between men and women
So, why are there differences between men and women in COVID-19?
Previously, researchers found that the key to novel coronavirus's infection of human cells lies in the combination of S protein of coronavirus and ACE2 protein in human body. Accurately speaking, the S protein of the virus hijacked ACE2, which was originally used to control blood pressure, and invaded the human body through its combination and induced infection.
However, according to the research results published in Cell magazine in March, COVID-19 needs to use a protease in human cells, namely serine protease TMPRSS2, in the process of activating its S protein.
The key point here is that TMPRSS2, as a key molecule to promote the occurrence of male prostate cancer, is positively regulated by androgen in human body. Therefore, Professor Ren Shancheng's team believes that the important factor that causes the difference between men and women in COVID-19 is the high androgen level in men and its regulation on key molecules of virus invasion.
Through the analysis of lung single cell sequencing data and other important databases, the researchers found several key features related to novel coronavirus virus infection in lung ACE2.
1 and single cell RNA-seq analysis showed that the number of type ⅱ alveolar cells expressing ACE2 in male lungs was significantly higher than that in female, which meant that the number of host cells that the virus could attack was more than that of female.
At the same time, the single cell RNA-seq data of prostate and testis found that ACE2 was universally expressed in these two male-specific organs, suggesting that prostate and testis may be potential targets of SARS-Cov-2 infection in male population.
On March 12, the website of Hubei Provincial People's Government published an article entitled "Birth Examination of School-age Men Infected with COVID-19" for the same reason.
2. Androgen receptor can directly and positively regulate the expression of ACE2.
It was found that androgen receptor and ACE2 showed a * * * expression pattern; Further analysis showed that androgen receptor was positively correlated with the expression of ACE2 and TMPRSS2, which were ubiquitous in many tissues and organs of human body. After androgen deprivation, the expressions of ACE2 and TMPRSS2 were also down-regulated. In addition, it is further suggested that androgen receptor may bind to the enhancer region upstream of ACE2 and promote the expression of ACE2.
3. It was found that many pro-inflammatory cytokines and chemokines were dominant in male population, especially the receptor of IL_6, the core factor of cytokine storm, was highly expressed in many cells of male lung, suggesting that men are more prone to cytokine storm and lead to the deterioration of COVID-19's disease. However, some cytokines, such as CCL2, CCL3 and CCL4, play a protective role against viral infection and are highly expressed in female population.
4. The killing ability of T cells in male lung microenvironment is weaker than that of female. This gender-based difference in natural immune response leads to male lung cells being weaker than female in resisting virus attacks.
According to Bio Art Reports, this study, through a large sample meta-analysis, clearly confirmed for the first time that the incidence, severity and mortality of men in COVID-19 are higher than those of women.
At the same time, it also reveals the biological reasons behind it, and proves that due to the positive regulation of androgen receptor, the expression and distribution of ACE2, the key molecule of COVID-19's invasion, is higher in male lung cells than in female; Moreover, the autoimmune response of male lung cells when attacked by virus is weaker than that of women.
All this points to a simple conclusion: men are more vulnerable than women in front of COVID-19.
abstract
In fact, before this article, the relationship between gender differences and COVID-19 has been studied.
Among them, in mid-February, the epidemic statistics report released by China Center for Disease Control and Prevention showed that 1 1 of the 44,672 cases diagnosed in COVID-19 as of February, and 5 1.4% of the patients in the national data were male; Because the ratio of male to female is close to 1: 1, CDC thinks that COVID-19 has not shown obvious sexual orientation.
But at the same time, the CDC report also shows that the mortality rate of male patients is significantly higher than that of female patients, the former is 2.8%, and the latter is only 1.7%.
At the beginning of March, a study published by the team of Wuhan University People's Hospital on the preprint platform SSRN gave a new view. Specifically, the researcher analyzed the data of 60 1 3 cases from/kloc-0 to 29, and found that 55.9% of the patients were male. Among the patients who entered the intensive care unit, 58.8% were male.
In other words, men are not only more likely to be infected with COVID-19 virus, but also seem to have more serious symptoms.
In addition, among the 67 asymptomatic infected people confirmed in this study, 47 are women, which shows that women also account for a large proportion of asymptomatic infected people. The researchers speculate that the gender difference of infected people may not be because the virus prefers to infect men, but because men and women have different resistance to the virus.
Nowadays, with the publication of Professor Ren Shancheng's team paper, the relationship between COVID-19 and gender differences seems to have a clearer and more controversial interpretation.
Last question: Do you think this interpretation is reliable?
For more information, COVID-19 is also a sexist! For more information about "Men are more susceptible to infection and have higher mortality rate", please continue to pay attention to the column of deep space science and technology information, and Bian Xiao will continue to update you with more science and technology news.
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