SARS-CoV-2 Infection during Delivery Causes Histopathological Changes in the Placenta.

BACKGROUND: SARS-CoV-2 can damage human placentas, leading to pregnancy complications, such as preeclampsia and premature birth. This study investigates the histopathological changes found in COVID-19-affected placentas. MATERIALS AND METHODS: This study included 23 placentas from patients with active COVID-19 during delivery and 22 samples from patients without COVID-19 infection in their medical history. The samples underwent histopathological examination for pathology, such as trophoblast necrosis, signs of vessel damage, or fetal vascular malperfusion. RESULTS: Newborns from the research group have lower weights and Apgar scores than healthy newborns. In the COVID-19 group, calcifications and collapsed intervillous space were more frequent, and inflammation was more severe than in the healthy group. At the same time, the placenta of SARS-CoV-2-positive patients showed signs of accelerated vascular maturation. Trophoblast necrosis was found only in the placentas of the research group. The expression of CD68+ was elevated in the COVID-19 cohort, suggesting that macrophages constituted a significant part of the inflammatory infiltrate. The increase in lymphocyte B markers was associated with placental infarctions, while high levels of CD3+, specific for cytotoxic T lymphocytes, correlated with vascular injury. CONCLUSIONS: SARS-CoV-2 is associated with pathological changes in the placenta, including trophoblast necrosis, calcification, and accelerated villous maturation. Those changes appear to be driven by T cells and macrophages, whose increased expression reflects ongoing histiocytic intervillositis in the placenta.

Mechanisms of SARS-CoV-2 Placental Transmission.

The widespread occurrence of SARS-CoV-2 infections and the diverse range of symptoms have placed significant strain on healthcare systems worldwide. Pregnancy has also been affected by COVID-19, with an increased risk of complications and unfavorable outcomes for expectant mothers. Multiple studies indicate that SARS-CoV-2 can infiltrate the placenta, breach its protective barrier, and infect the fetus. Although the precise mechanisms of intrauterine transmission remain unclear, factors such as perinatal infection, macrophages, sexual intercourse, and the virus' interaction with host angiotensin-converting enzyme 2 (ACE2) and neuropilin-1 (NRP-1) proteins appear to play a role in this process. The integrity of the placental barrier fluctuates throughout pregnancy and appears to influence the likelihood of fetal transmission. The expression of placental cell receptors, like ACE2, changes during pregnancy and in response to placental damage. However, due to the consistent presence of others, such as NRP-1, SARS-CoV-2 may potentially enter the fetus at different stages of pregnancy. NRP-1 is also found in macrophages, implicating maternal macrophages and Hofbauer cells as potential routes for viral transmission. Our current understanding of SARS-CoV-2's vertical transmission pathways remains limited. Some researchers question the ACE2-associated transmission model due to the relatively low expression of ACE2 in the placenta. Existing studies investigating perinatal transmission and the impact of sexual intercourse have either involved small sample sizes or lacked statistical significance. This review aims to explore the current state of knowledge regarding the potential mechanisms of COVID-19 vertical transmission, identifying areas where further research is needed to fill the gaps in our understanding.

Blood type ABO and the cytokine profile of follicular fluid in women undergoing IVF/ET.

OBJECTIVES: ABO blood type was hypothesised to be related to a number of infertility processes. There is still an open debate on ABO blood group's incompatibility and infertility. It was associated with ovarian reserve in women with subfertility. There is still not enough information on the influence of blood type and the immunology of follicular fluid (FF). MATERIAL AND METHODS: 78 patients were selected, who underwent in vitro fertilization (IVF) between April 2021 and January 2022. FF samples from each individual patient were taken on the day of ovarian puncture and stored at -80°C until immunological assessment. Concentration of chosen interleukins - IL-1α, IL-2, IL-4, IL-5, IL-6, IL-8 IL-10, IL-15, IL-1ß, IL-18, IFN, LIF, TNFα, GCSF and PIBF-1 were measured using commercially available ELISA kits. RESULTS: All assessed cytokines were present in the FF of exanimated patients. The concentration was compared to the blood type ABO of all women undergoing in vitro fertilization. No statistical relevance was found between blood type ABO and the concentration of GCSF, PIBF1, LIF, IL-15, IL-5, IL-8, IL-1 alfa, IL-1 beta, INF gamma, IL-2HS, IL-4HS, IL-6HS, IL-10HS in the FF obtained during ovarian puncture (p > 0,05). There was no statistically significant correlation between blood type ABO and the quality of embryo, and the positive pregnancy test in patients undergoing IVF/ET. CONCLUSIONS: The blood type ABO does not influence the wide cytokine profile of FF obtained during ovarian puncture in women with infertility of different origin, as well as embryo quality and pregnancy rate.