Mechanisms and possible controls of the in utero Zika virus infection: Where is the Holy Grail?

Roles of TGF-β1 in Viral Infection during Pregnancy: Research Update and Perspectives

Transforming growth factor-beta 1 (TGF-β1) is a pleiotropic growth factor playing various roles in the human body including cell growth and development. More functions of TGF-β1 have been discovered, especially its roles in viral infection. TGF-β1 is abundant at the maternal-fetal interface during pregnancy and plays an important function in immune tolerance, an essential key factor for pregnancy success. It plays some critical roles in viral infection in pregnancy, such as its effects on the infection and replication of human cytomegalovirus in syncytiotrophoblasts. Interestingly, its role in the enhancement of Zika virus (ZIKV) infection and replication in first-trimester trophoblasts has recently been reported. The above up-to-date findings have opened one of the promising approaches to studying the mechanisms of viral infection during pregnancy with links to corresponding congenital syndromes. In this article, we review our current and recent advances in understanding the roles of TGF-β1 in viral infection. Our discussion focuses on viral infection during pregnancy, especially in the first trimester. We highlight the mutual roles of viral infection and TGF-β1 in specific contexts and possible functions of the Smad pathway in viral infection, with a special note on ZIKV infection. In addition, we discuss promising approaches to performing further studies on this topic.

Placental barrier against COVID-19

Vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and possible induction of pregnancy complications, including miscarriage, fetal malformations, fetal growth restriction and/or stillbirth, are serious concerns for pregnant individuals with COVID-19. According to clinical information, the incidence of vertical transmission of SARS-CoV-2 is limited to date. However, even if a neonate tests negative for SARS-CoV-2, frequent abnormal findings, including fetal and maternal vascular malperfusion, have been reported in cases of COVID-19-positive mothers. Primary receptor of SARS-CoV-2 is estimated as angiotensin-converting enzyme 2 (ACE2). It is highly expressed in maternal-fetal interface cells, such as syncytiotrophoblasts, cytotrophoblasts, endothelial cells, and the vascular smooth muscle cells of primary and secondary villi. However other route of transplacental infection cannot be ruled out. Pathological examinations have demonstrated that syncytiotrophoblasts are often infected with SARS-CoV-2, but fetuses are not always infected. These findings suggest the presence of a placental barrier, even if it is not completely effective. As the frequency and molecular mechanisms of intrauterine vertical transmission of SARS-CoV-2 have not been determined to date, intensive clinical examinations by repeated ultrasound and fetal heart rate monitoring are strongly recommended for pregnant women infected with COVID-19. In addition, careful investigation of placental samples after delivery by both morphological and molecular methods is also strongly recommended.

Zika virus: - a review of the main aspects of this type of arbovirosis

The objective of this study was to integrate findings related to Zika virus from the scientific literature. An integrative review of Medline was conducted, and data search was performed using the Health Sciences Descriptor Zika virus and the following filters: full texts available; studies in humans; full articles; and publications in Portuguese, French, English, and Spanish. After application of the filters, followed by reading of the titles, abstracts, and full texts, 44 studies were included in the review, for which content analysis was performed. A large part of the literature comprised review articles (84%; N=37); the majority was in English (95%, N=42). In 2016, 84% (N=37) of our sample articles was published, while in 2017, 16% (N=7) was published. The main form of viral transmission was thorough the mosquito Aedes aegypti (N=30). In addition, sexual transmission (N=09), transmission through blood transfusion (N=16), vertical transmission (N=21) and transmission from occupational activities (N=03) occurred. It was possible to diagnose the disease by testing blood (N=22), urine (N=14), saliva (N=06), semen/sperm (N=03), cerebrospinal and amniotic fluid, and other tissues (N=02). Symptomatology occurred in 1-5 people (N=10) between 3 and 7 days after a mosquito bite (N=09). Complications observed were Guillain Barré syndrome (N=27); neurological Zika syndrome (N=27); meningitis, meningoencephalitis, and myelitis (N=07); deaths and/or newborns (N=03). The review provides scientific evidence that contributes to the care, planning and implementation of public policies.