Placental barrier against COVID-19

The Japanese Medical Science Federation COVID-19 Expert Opinion English Version

In 2020, the COVID-19 pandemic has had unprecedented impacts on various aspects of the world. Each academic society has published a guide and/or guidelines on how to cope with COVID-19 separately. As the one and only nationwide association of academic societies that represent medical science in Japan, JMSF has decided to publish the expert opinion to help patients and care providers find specifically what they want. This expert opinion is a summary of recommendations by many academic societies and will be updated when necessary. Patients that each academic society targets differ even though they suffer from the same COVID-19, and recommendations can be different in a context-dependent manner. Readers are supposed to be flexible and adjustable when they use this expert opinion.

Term Human Placental Trophoblasts Express SARS-CoV-2 Entry Factors ACE2, TMPRSS2, and Furin

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a massive impact on human lives worldwide. While the airborne SARS-CoV-2 primarily affects the lungs, viremia is not uncommon. As placental trophoblasts are directly bathed in maternal blood, they are vulnerable to SARS-CoV-2. Intriguingly, the human fetus is largely spared from SARS-CoV-2 infection. We tested whether the human placenta expresses the main SARS-CoV-2 entry factors angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), and furin and showed that ACE2 and TMPRSS2 are expressed in the trophoblast rather than in other placental villous cells. While furin is expressed in the main placental villous cell types, we surveyed, trophoblasts exhibit the highest expression. In line with the expression of these entry factors, we demonstrated that a SARS-CoV-2 pseudovirus could enter primary human trophoblasts. Mechanisms underlying placental defense against SARS-CoV-2 infection likely involve postentry processing, which may be germane for mitigating interventions against SARS-CoV-2.

IMPORTANCE Pregnant women worldwide have been affected by COVID-19. As the virus is commonly spread to various organs via the bloodstream and because human placental trophoblasts are directly bathed in maternal blood, feto-placental infection by SARS-CoV-2 seems likely. However, despite the heightened risk to pregnant women, thus far the transmission risk of COVID-19 to the feto-placental unit seems extremely low. This has been recently attributed to a negligible expression of SARS-CoV-2 entry factors in the human placenta. We therefore sought to explore the expression of the entry factors ACE2 and TMPRSS2 in the different cell types of human placental villi. Using a combination of transcriptome sequencing (RNA-seq), real-time quantitative PCR (RT-qPCR), in situ hybridization, and immunofluorescence, we found that trophoblasts, but not the other main villous cell types, express ACE2 and TMPRSS2, with a broad expression of furin. Correspondingly, we also showed that primary human trophoblasts are permissive to entry of SARS-CoV-2 pseudovirus particles.

SARS-CoV-2 colonization of maternal and fetal cells of the human placenta promotes alteration of local renin-angiotensin system

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection appears to increase the risk of adverse pregnancy outcomes, such as pre-eclampsia in pregnant women. The mechanism(s) by which this occurs remains unclear.

Methods

We investigated the pathophysiology of SARS-CoV-2 at maternal-fetal interface in pregnant women who tested positive for the virus using RNA in situ hybridization (viral RNA), immunohistochemistry, and hematoxylin and eosin staining. To investigate whether viral infection alters the renin angiotensin system (RAS) in placenta, which controls blood pressure, we treated human trophoblasts with recombinant spike protein or a live modified virus with a vesicular stomatitis viral backbone expressing spike protein (VSV-S).

Findings

Viral colonization was highest in maternal decidua, fetal trophoblasts, Hofbauer cells, and in placentas delivered prematurely. We localized SARS-CoV-2 to cells expressing angiotensin-converting enzyme 2 (ACE2) and demonstrate that infected placentas had significantly reduced ACE2. In response to both spike protein and VSV-S, cellular ACE2 decreased although angiotensin II receptor type 1 (AT₁R) increased with concomitant increase in soluble fms-like tyrosine kinase-1 (sFlt1). Viral infection decreased pro-angiogenic factors, AT₂R, and placental growth factor, which competitively binds to sFlt1. Sera from infected pregnant women had elevated levels of sFlt1 and angiotensin II type 1-receptor autoantibodies prior to delivery, both signatory markers of pre-eclampsia.

Conclusions

SARS-CoV-2 colonizes ACE2-expressing maternal and fetal cells in the placenta. Infection in pregnant women correlates with alteration of placental RAS. As RAS regulates blood pressure, SARS-CoV-2 infection may thus increase adverse hemodynamic outcomes, such as pre-eclampsia in pregnant women.

Funding

NIH/NICHD grants R01 HD091218 and 3R01HD091218-04S1 (RADx-UP Supplement).

COVID-19, Chikungunya, Dengue and Zika Diseases: An Analytical Platform Based on MALDI-TOF MS, IR Spectroscopy and RT-qPCR for Accurate Diagnosis and Accelerate Epidemics Control

COVID-19 and arboviruses (ARBOD) epidemics co-occurrence is a great concern. In tropical and subtropical regions, ARBOD diseases such as chikungunya, dengue, and Zika are frequent. In both COVID-19 and ARBOD cases, an accurate diagnosis of infected patients is crucial to promote adequate treatment and isolation measures in COVID-19 cases. Overlap of clinical symptoms and laboratory parameters between COVID-19 and ARBOD present themselves as an extra challenge during diagnosis. COVID-19 diagnosis is mainly performed by quantitative reverse polymerase chain reaction (RT-qPCR), while ARBOD diagnosis is performed by serology, detection of antigen or antibody, and molecular diagnosis. In this review, the epidemiologic profile of arboviruses and SARS-CoV-2 is analyzed, and potential risks of symptom overlap is addressed. The implementation of an analytical platform based on infrared (IR) spectroscopy, MALDI-TOF mass spectrometry, and RT-qPCR is discussed as an efficient strategy for a fast, robust, reliable, and cost-effective diagnosis system even during the co-occurrence of virus outbreaks. The spectral data of IR spectroscopy and MALDI-TOF MS obtained from COVID-19 infected and recovered patients can be used to build up an integrated spectral database. This approach can enable us to determine quickly the groups that have been exposed and have recovered from COVID-19 or ARBOD, avoiding misdiagnoses.

A Comprehensive Analysis of Maternal and Newborn Disease and Related Control for COVID-19

The maternal-fetal/newborn unit is established at risk for COVID-19 infection. This narrative review summarizes the contemporary and cumulative publications which detail maternal infection, antenatal and newborn infections, and maternal/fetal/newborn management and prevention. There is a wide spectrum of maternal disease, but the potential for severe disease albeit in a minority is confirmed. COVID-19 carries risk for preterm delivery. Pregnant females can suffer multisystem disease, and co-morbidities play a significant role in risk. Congenital infection has been supported by several anecdotal reports, but strong confirmatory data are few. No typical congenital dysmorphisms are evident. Nevertheless, placental vascular compromise must be considered a risk for the fetus during advanced maternal infections. Clinical manifestations of newborn infection have been mild to moderate and relatively uncommon. Proven antiviral therapy is of yet lacking. The mode of delivery is a medical decision that must include patient risk assessment and patient directives. Both presymptomatic and asymptomatic mothers and offspring can complicate infection control management with the potential for spread to others in several regards. In the interim, infections of the maternal-fetal-newborn unit must be taken seriously both for the disease so caused and the potential for further dissemination of disease.

Doppler assessment of the fetus in pregnant women recovered from COVID-19

OBJECTIVE

The aim of this study was to evaluate the maternal-fetal Doppler patterns in pregnant women recovered from COVID-19.

METHODS

This prospective case-control study was conducted in Ankara City Hospital between July 1, 2020 and August 30, 2020. Thirty pregnant women who were diagnosed with COVID-19 and completed the quarantine process were compared with 40 healthy pregnant women in terms of the fetal Doppler parameters. All pregnant women diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were followed up in our clinic and their diagnoses have been confirmed in nasopharyngeal and oropharyngeal samples by quantitative real time reverse transcriptase polymerase chain reaction (RT-PCR) method. Doppler ultrasonographic assessment of the uterine arteries (UtA) and middle cerebral artery (MCA) were used in addition to umbilical artery (UA) Doppler between 23 and 40 weeks of gestation. Also, cerebroplacental ratio (CPR) was calculated according to gestational age.

RESULTS

The pulsatility and resistance indices of umbilical and UtA showed a significant increase in pregnant women in the study group compared to the control group (p < 0.05). Multivariable logistic regression analysis revealed that pulsatility and resistance indices of the mean UtA were independently associated with disease (OR > 1000, 95%CI 9.77 to >1000, p = 0.009; OR 0,000 95%CI 0,000-0,944, p = 0,049), respectively. Medical treatment was given to 16/30 (53%) of pregnant women diagnosed with COVID-19.

CONCLUSION

In conclusion, uterine artery Doppler indices in the third trimester may have clinical value in pregnant women recovered from COVID-19.

Being pregnant in the COVID-19 pandemic: Effects on the placenta in all aspects

The coronavirus disease 2019 (COVID‐19), which had spread to the world from Wuhan (China) in late December, was announced as a pandemic by the World Health Organization in March 2020. In addition to acute respiratory syndrome symptoms, this virus also affects nonrespiratory organs, according to existing data. ACE2 and TMPRSS2, which play a critical role in the entrance of SARS‐COV‐2 into the cell, are coexpressed in placental development stages, so the placenta also carries a risk for this virus. Many studies have shown that this virus causes some histopathological changes in the placenta. The vertical transmission of the virus is not yet clear, but available data have shown that the indirect effects of the virus can be seen on the fetus. This article focuses on revealing the effects of the virus on the placenta in all aspects.

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The placenta also shows antiviral activity due to placental growth factors, cytokines, and chemokines, so the use of placental extracts as therapeutic agents in the treatment of COVID‐19 needs authority regulations and clinical guidelines.

Investigating the risk of maternal-fetal transmission of SARS-CoV-2 in early pregnancy

Introduction

The possibility of vertical transmission of SARS-CoV-2 from the mother to the fetus is one of the most crucial issues regarding the COVID-19 effects on pregnancy. In this study, we aimed to explore the risk of maternal-fetal transmission before 24 weeks of gestation, through analysis of abortion materials collected from PCR-positive women with pregnancy loss. To the best of our knowledge, apart from case reports, this study is the first prospective work on the vertical transmission of SARS-CoV-2 in early pregnancy.

Methods

The patients who had attended our clinic with the diagnosis of pregnancy loss before 24 weeks of gestation were screened for COVİD-19. Vertical transmission in PCR-positive women was assessed through the presence of SARS-CoV-2 RNA in fetal-placental tissues by rt-PCR test.

Results

24 of 210 (%11,4) pregnant women participating in the study had positive rt-PCR results. Placenta and curettage material samples of these PCR-positive patients were analyzed and all valid test results (21 samples) were negative for SARS CoV-2 RNA. In three cases, the rt-PCR results were invalid due to failed internal controls.

Discussion

In the literature, the possibility of intrauterine vertical transmission of SARS-CoV-2 is still controversial. The findings of the present study did not reveal any evidence of vertical transmission of SARS-CoV-2 in early pregnancy.

Comprehensive analysis of COVID-19 during pregnancy

The COVID-19 pandemic resulting from the emergence of the coronavirus SARS-CoV-2 remains a major global health concern. Pregnant individuals are more likely to develop severe COVID-19 and a number of pregnancy complications have been observed in COVID-19 patients. To date, little is known about the impact of COVID-19 on pregnancy. In this review, we examine key aspects of pregnancy that may be impacted by COVID-19 and summarize the current literature on SARS-CoV-2 infection of the placenta and in utero vertical transmission. Furthermore, we highlight recent studies exploring the role of the maternal antibody response to SARS-CoV-2 during pregnancy and the passive transfer of maternal antibodies from mothers with COVID-19 to fetus.

Placental pathology and fetal demise at 35 weeks of gestation in a woman with SARS-CoV-2 infection: A case report

The consequences of SARS-CoV-2 infection in pregnancy have not been well defined. However, there have been a number of reports of poor maternal and fetal outcomes worldwide. This report presents a case of stillbirth with associated placental pathology during week 35 in an otherwise healthy pregnant woman with SARS-CoV-2 infection.

Placental findings in this case showed patchy acute chorionitis and diffuse infarction/villous necrosis of the placental parenchyma resulting in extensive vascular malperfusion. Fetal autopsy was most significant for placental findings and no congenital malformations were discovered. The findings in this case are consistent with reports in the literature of pathological placental changes associated with COVID-19.

This case of fetal demise in a woman with confirmed SARS-CoV-2 infection without any other medical or obstetric disorders and no alternate cause suggests that fetal death can be an outcome of COVID-19 during pregnancy. This outcome was supported by the histopathological findings in the placenta.

Continued research is imperative to confirm the findings in this case and multiple similar cases. Additionally, increased screening and collection of COVID-19 data specific to pregnant women and their fetuses and infants is needed to increase knowledge, support research efforts, and create guidelines for clinical practice that will prevent potential negative outcomes and loss of life.

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Describes a case of stillbirth during week 35 in an otherwise healthy pregnant woman with SARS-CoV-2 infection

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Placental pathology associated with SARS-CoV-2 infection seen in the current literature is consistent in this case

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This case suggests stillbirth is a potential outcome of COVID-19 infection during pregnancy

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Findings warrant increased surveillance of and prevention of gaps in care for this vulnerable patient population

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Findings warrant increased collection of COVID-19 data specific to pregnant women and continued placental pathology research research

[Infection with SARS-CoV-2 in pregnancy. Update of Information and proposed care. CNGOF]

OBJECTIVES

The coronavirus SARS-CoV-2 identified late 2019 in China had spread across all continents. In the majority of cases, patients have mild symptoms (fever, cough, myalgia, headache, some digestive disorders) or are asymptomatic, however it can cause serious lung diseases and lead to death. On September 2020, over 28 million people have been infected with over 920,000 deaths.

METHODS

In view of the evolution of the epidemic the French National College of Obstetricians and Gynecologists has decided to update the recommendations previously issued. To do this, the same group of experts was called upon to carry out a review of the literature and take into account the opinions of the General Directorate of Health (DGS), the "Haute Autorité de Santé" (HAS) and the "Haut Conseil de santé Publique" (HCSP).

RESULTS

The data on consequences during pregnancy have accumulated. The symptoms in pregnant women appear to be similar to those of the general population, but an increased risk of respiratory distress exists in pregnant women especially in the third trimester. A case of intrauterine maternal-fetal transmission has been clearly identified. Induced prematurity and cases of respiratory distress in newborns of infected mothers have been described.

CONCLUSION

In light of the new data, we propose updated recommendations. These proposals may continue to evolve in view of the pandemic and of advances in studies in pregnant women.

Impact of Covid-19 in pregnancy on mother's psychological status and infant's neurobehavioral development: a longitudinal cohort study in China

BACKGROUND

Evidence concerning the long-term impact of Covid-19 in pregnancy on mother's psychological disorder and infant's developmental delay is unknown.

METHODS

This study is a longitudinal single-arm cohort study conducted in China between May 1 and July 31, 2020. Seventy-two pregnant patients with Covid-19 participated in follow-up surveys until 3 months after giving birth (57 cases) or having abortion (15 cases). We collected data from medical records regarding Covid-19, delivery or abortion, testing results of maternal and neonatal specimens, and questionnaires of quarantine, mother-baby separation, feeding, and measuring of mothers' mental disorders and infants' neurobehavioral disorders.

RESULTS

All cases infected in the first trimester and 1/3 of cases infected in the second trimester had an abortion to terminate the pregnancy. 22.2% of pregnant patients were suffering from post-traumatic stress disorder or depression at 3 months after delivery or induced abortion. Among 57 live births, only one neonate was positive of nucleic acid testing for throat swab, but negative in repeated tests subsequently. The median duration of mother-baby separation was 35 days (interquartile range 16 to 52 days). After the termination of maternal quarantine, 49.1% of mothers chose to prolong the mother-baby separation (median 8 days; IQR 5 to 23 days). The breastfeeding rate was 8.8% at 1 week after birth, 19.3% at the age of 1 month, and 36.8% at the age of 3 months, respectively. The proportion of "monitoring" and "risk" in the social-emotional developmental domain at the age of 3 months was 22.7% and 63.6%, respectively. After the adjustment of preterm, neonatal sex, admitted to NICU, and the mother's Covid-19 condition, the negative associations were significantly identified (p < 0.05) between mother-baby separation days and three developmental domains: communication, gross motor, and personal-social.

CONCLUSIONS

There is no definite evidence on vertical transmission of SARS-CoV-2. In addition to control infection risk, researchers and healthcare providers should pay more attention to maternal mental health and infant's feeding, closeness with parents, and early development.