Human Oocytes Express Both ACE2 and BSG Genes and Corresponding Proteins: Is SARS-CoV-2 Infection Possible?

Ovarian granulosa cells from women with PCOS express low levels of SARS-CoV-2 receptors and co-factors

Purpose

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is global pandemic with more than 5 million deaths so far. Female reproductive tract organs express coronavirus-associated receptors and factors (SCARFs), suggesting they may be susceptible to SARS-CoV-2 infection; however, the susceptibility of ovary/follicle/oocyte to the same is still elusive. Co-morbidities like obesity, type-2 diabetes mellitus, cardiovascular disease, etc. increase the risk of SARS-CoV-2 infection. These features are common in women with polycystic ovary syndrome (PCOS), warranting further scope to study SCARFs expression in ovary of these women.

Materials and methods

SCARFs expression in ovary and ovarian tissues of women with PCOS and healthy women was explored by analyzing publically available microarray datasets. Transcript expressions of SCARFs were investigated in mural and cumulus granulosa cells (MGCs and CGCs) from control and PCOS women undergoing in vitro fertilization (IVF).

Results

Microarray data revealed that ovary expresses all genes necessary for SARS-CoV-2 infection. PCOS women mostly showed down-regulated/unchanged levels of SCARFs. MGCs and CGCs from PCOS women showed lower expression of receptors ACE2, BSG and DPP4 and protease CTSB than in controls. MGCs showed lower expression of protease CTSL in PCOS than in controls. Expression of TMPRSS2 was not detected in both cell types.

Conclusion

Human ovarian follicle may be susceptible to SARS-CoV-2 infection. Lower expression of SCARFs in PCOS indicates that the risk of SARS-CoV-2 infection to the ovary may be lesser in these women than controls. This knowledge may help in safe practices at IVF settings in the current pandemic.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00404-022-06567-4.

Oncofertility and COVID-19: At the Crossroads between Two Time-Sensitive Fields

Background: COVID-19 infection has dominated our lives and left its mark on it. The impact on fertility is major, and the long-term consequences may be disastrous. When we talk about oncofertility, we are talking about those patients worried about the delay in receiving medical services (possible cancelation of surgery, decreased availability of medical services, reorientation of medical resources) due to COVID-19. Finally, patients’ worsening biological and reproductive statuses, associated with high levels of anxiety and depression, are closely related to social restrictions, economic impact, reorientation of medical resources, health policies, and fears of SARS-CoV-2 infection. Aim: We reviewed the current literature on fertility during the COVID-19 pandemic and its effect on cancer patients. Specifically, how cancer treatment can affect fertility, the options to maintain fertility potential, and the recovery options available after treatment are increasingly common concerns among cancer patients. Methods: A systematic literature search was conducted using two main central databases (PubMed^®/MEDLINE, and Web of Science) to identify relevant studies using keywords SARS-CoV-2, COVID-19, oncofertility, young cancer patient, cryopreservation, assisted reproductive techniques (ART), psychosocial, telemedicine. Results: In the present study, 45 papers were included, centered on the six main topics related to COVID-19. Conclusions: Fertility preservation (FP) should not be discontinued, but instead practiced with adjustments to prevent SARS-CoV-2 transmission. The increased risk of SARS-CoV-2 infection in cancer patients requires screening for COVID-19 before FP procedures, among both patients and medical staff in FP clinics, to prevent infection that would rapidly worsen the condition and lead to severe complications.

The Effects of SARS-CoV-2 Infection on Female Fertility: A Review of the Literature

As the coronavirus pandemic is far from ending, more questions regarding the female reproductive system, particularly fertility issues, arise. The purpose of this paper is to bring light upon the possible link between COVID-19 and women’s reproductive health. This review emphasizes the effect of SARS-CoV-2 on the hormones, endometrium and menstrual cycle, ovarian reserve, follicular fluid, oocytes, and embryos. The results showed that endometrial samples did not express SARS-CoV-2 RNA. Regarding the menstrual cycle, there is a large range of alterations, but they were all reversible within the following months. The ovarian reserve was not significantly affected in patients recovering from both mild and severe infection in most cases, except one, where the levels of AMH were significantly lower and basal follicle-stimulating hormone (FSH) levels were increased. All COVID-19 recovered patients had positive levels of SARS-CoV-2 IgG in the follicular fluid. The amount of retrieved and mature oocytes and the fertilization rate were unharmed in three studies, except for one study, where the quantity of retrieved and mature oocytes was reduced in patients with higher levels of SARS-CoV-2 antibodies. The numbers of blastocysts, top-quality embryos, and euploid embryos were affected in most of the studies reviewed.

The impact of COVID-19 on human reproduction and directions for fertility treatment during the pandemic

Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly, resulting in a pandemic. The virus enters host cells through angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2). These enzymes are widely expressed in reproductive organs; hence, coronavirus disease 2019 (COVID-19) could also impact human reproduction. Current evidence suggests that sperm cells may provide an inadequate environment for the virus to penetrate and spread. Oocytes within antral follicles are surrounded by cumulus cells, which rarely express ACE2 and TMPRSS2. Thus, the possibility of transmission of the virus through sexual intercourse and assisted reproductive techniques seems unlikely. Early human embryos express coronavirus entry receptors and proteases, implying that human embryos are potentially vulnerable to SARS-CoV-2 in the early stages of development. Data on the expression of ACE2 and TMPRSS2 in the human endometrium are sparse. Moreover, it remains unclear whether SARS-CoV-2 directly affects the embryo and its implantation. A study of the effect of SARS-CoV-2 on pregnancy showed an increase in preterm delivery. Thus, vertical transmission of the virus from mother to fetus in the third trimester is possible, and further data on human reproduction are required to establish this possibility. Based on analyses of existing data, major organizations in this field have published guidelines on the treatment of infertility. Regarding these guidelines, despite the COVID-19 pandemic, reproductive treatment is crucial for the well-being of society and must be continued under suitable regulations and good standard laboratory practice protocols.

Female fertility under the impact of COVID-19 pandemic: a narrative review

Coronavirus disease 2019 (COVID-19) is a serious respiratory disease mediated by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The worldwide spread of COVID-19 has caused millions of confirmed cases and morbidity, and the crisis has greatly affected global economy and daily life and changed our attitudes towards life. The reproductive system, as a potential target, is at a high risk of SARS-CoV-2 infection, and females are more vulnerable to viral infection compared with males. Therefore, female fertility and associated reproductive health care in the COVID-19 era need more attention. This review summarises the mechanism of SARS-CoV-2 infection in the female reproductive system and discusses the impact of the COVID-19 crisis on female fertility. Studies have proven that COVID-19 might affect female fertility and interfere with assisted reproductive technology procedures. The side effects of vaccines against the virus on ovarian reserve and pregnancy have not yet been well investigated. In the future, the female fertility after SARS-CoV-2 infection and vaccination needs more attention because of the uncertainty of COVID-19.

SARS-CoV-2 vs. human gametes, embryos and cryopreservation

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, is an unprecedented global situation, and all countries have adopted their own measurements to mitigate the spread of the virus in the first as well as in the subsequent waves of infection. All measures, especially in the first wave of the pandemic, were in combination with recommendations provided by professional and scientific organizations. Similar measures were applied to specific procedures, such as the management of infertility, including in vitro fertilization-embryo transfer (IVF-ET) treatments. Although there is no clear scientific evidence yet that the SARS-CoV-2 may exert negative effects on IVF outcome, especially at the early stages, several clinical reports indicate that the virus may impact male fertility through specific receptors presented at the somatic cells of the testis and used by the virus in order to gain entry to the respective cells. Nevertheless, it is not unreasonable to suspect that the virus may affect sperm function as well as oocyte performance directly through specific receptors or indirectly through other signaling pathways. Despite the good practice of IVF laboratory techniques, culture media may also be contaminated during equilibration when airborne virus's particles can contaminate culture media from an already infected embryology area or staff. Furthermore, although there is no clinical evidence, liquid nitrogen could be a route of infection for gametes and embryos when it has been contaminated during production or transportation. Therefore, cryopreservation of gametes and embryos must be virus-free. This communication aims to provide some aspects of the possible impact of the virus on gametes and embryos and how it may affect the cryopreservation procedures.Abbreviations: ACE2: angiotensin- converting enzyme 2; ART: assisted reproductive technology; ASRM: American Society for Reproductive Medicine; CDC: Centers for Disease Control and Prevention; COVID-19: coronavirus disease 2019; ESHRE: European Society of Human Reproduction and Embryology; ET: embryo transfer; FSH: follicle stimulating hormone; IFFS: International Federation of Fertility Societies; IVF: in vitro fertilization; LH: luteinizing hormone; LN: liquid nitrogen; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; T: testosterone; WHO: World Health Organization.