Exaptation of Retroviral Syncytin for Development of Syncytialized Placenta, Its Limited Homology to the SARS-CoV-2 Spike Protein and Arguments against Disturbing Narrative in the Context of COVID-19 Vaccination

Cell-Cell Fusion in Cancer: The Next Cancer Hallmark?

In this review, we consider the role of cell-cell fusion in cancer development and progression through an evolutionary lens. We begin by summarizing the origins of fusion proteins (fusogens), of which there are many distinct classes that have evolved through convergent evolution. We then use an evolutionary framework to highlight how the persistence of fusion over generations and across different organisms can be attributed to traits that increase fitness secondary to fusion; these traits map well to the expanded hallmarks of cancer. By studying the tumor microenvironment, we can begin to identify the key selective pressures that may favor higher rates of fusion compared to healthy tissues. The paper concludes by discussing the increasing number of research questions surrounding fusion, recommendations for how to answer them, and the need for a greater interest in exploring cell fusion and evolutionary principles in oncology moving forward.

Impact of COVID-19 Vaccination on In Vitro Fertilization Outcomes: A Systematic Review

COVID-19 vaccination, especially vaccines that mimic the structure of the COVID-19 virus (mRNA vaccines), may be wrongly assumed to be disrupting factors affecting in vitro fertilization (IVF) outcome. This study aims to evaluate any significant impact of COVID-19 vaccination in women undergoing IVF to improve vaccine compliance and promote COVID-19 eradication. This was a systematic review study. We searched studies published between 2020 and 2022 using databases such as PubMed, Cochrane, PMC, and CINAHL. Selected studies were carefully analyzed to review the impact of the COVID-19 vaccine on IVF outcomes. Seven retrospective and prospective cohort studies, which involved 3232 female patients undergoing IVF, who also received full doses of COVID-19 vaccinations (mRNA), were included. All studies in the present review showed that despite presenting anti-SARS-CoV-2 antibodies after vaccination, there were no significant differences in IVF outcomes, implantation rates, and pregnancy rates. Contrary to the theory that presumed cross-reactivity between anti- SARS-CoV-2 antibodies and the human syncytin-1 protein could affect syncytiotrophoblast formation and embryo implantation. The present review concluded that COVID-19 vaccination does not result in any detrimental effects on IVF outcomes and is safe for women undergoing IVF treatment. The results of our study are important to tackle misinformation regarding COVID-19 vaccination and infertility that may cause vaccine hesitancy in women of reproductive age.

Coronavirus Disease 2019 (COVID-19) Vaccination and Assisted Reproduction Outcomes: A Systematic Review and Meta-analysis

OBJECTIVE

To assess the association between coronavirus disease 2019 (COVID-19) vaccination and female assisted reproduction outcomes through a systematic review and meta-analysis.

DATA SOURCES

We searched Medline (OVID), EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov on January 11, 2023, for original articles on assisted reproduction outcomes after COVID-19 vaccination. The primary outcome was rates of clinical pregnancy; secondary outcomes included number of oocytes retrieved, number of mature oocytes retrieved, fertilization rate, implantation rate, ongoing pregnancy rate, and live-birth rate.

METHODS OF STUDY SELECTION

Two reviewers independently screened citations for relevance, extracted pertinent data, and rated study quality. Only peer-reviewed published studies were included.

TABULATION, INTEGRATION, AND RESULTS

Our query retrieved 216 citations, of which 25 were studies with original, relevant data. Nineteen studies reported embryo transfer outcomes, with a total of 4,899 vaccinated and 13,491 unvaccinated patients. Eighteen studies reported data on ovarian stimulation outcomes, with a total of 1,878 vaccinated and 3,174 unvaccinated patients. There were no statistically significant results among our pooled data for any of the primary or secondary outcomes: clinical pregnancy rate (odds ratio [OR] 0.94, 95% CI 0.88-1.01, P =.10), number of oocytes retrieved (mean difference -0.26, 95% CI -0.68 to 0.15, P =.21), number of mature oocytes retrieved (mean difference 0.31, 95% CI -0.14 to 0.75, P =.18), fertilization rate (OR 0.99, 95% CI 0.87-1.11, P =.83), implantation rate (OR 0.92, 95% CI 0.84-1.00, P =.06), ongoing pregnancy rate (OR 0.95, 95% CI 0.86-1.06, P =.40), or live-birth rate (OR 0.95, 95% CI 0.78-1.17, P =.63). A subanalysis based on country of origin and vaccine type was also performed for the primary and secondary outcomes and did not change the study results.

CONCLUSION

Vaccination against COVID-19 is not associated with different fertility outcomes in patients undergoing assisted reproductive technologies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42023400023.

The risk of miscarriage following COVID-19 vaccination: a systematic review and meta-analysis

STUDY QUESTION

What is the risk of miscarriage among pregnant women who received any of the COVID-19 vaccines?

SUMMARY ANSWER

There is no evidence that COVID-19 vaccines are associated with an increased risk of miscarriage.

WHAT IS KNOWN ALREADY

In response to the COVID-19 pandemic, the mass roll-out of vaccines helped to boost herd immunity and reduced hospital admissions, morbidity, and mortality. Still, many were concerned about the safety of vaccines for pregnancy, which may have limited their uptake among pregnant women and those planning a pregnancy.

STUDY DESIGN, SIZE, DURATION

For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, and Cochrane CENTRAL from inception until June 2022 using a combination of keywords and MeSH terms.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included observational and interventional studies that enrolled pregnant women and evaluated any of the available COVID-19 vaccines compared to placebo or no vaccination. We primarily reported on miscarriage in addition to ongoing pregnancy and/or live birth.

MAIN RESULTS AND THE ROLE OF CHANCE

We included data from 21 studies (5 randomized trials and 16 observational studies) reporting on 149 685 women. The pooled rate of miscarriage among women who received a COVID-19 vaccine was 9% (n = 14 749/123 185, 95% CI 0.05-0.14). Compared to those who received a placebo or no vaccination, women who received a COVID-19 vaccine did not have a higher risk of miscarriage (risk ratio (RR) 1.07, 95% CI 0.89-1.28, I2 35.8%) and had comparable rates for ongoing pregnancy or live birth (RR 1.00, 95% CI 0.97-1.03, I2 10.72%).

LIMITATIONS, REASONS FOR CAUTION

Our analysis was limited to observational evidence with varied reporting, high heterogeneity and risk of bias across included studies, which may limit the generalizability and confidence in our findings.

WIDER IMPLICATIONS OF THE FINDINGS

COVID-19 vaccines are not associated with an increase in the risk of miscarriage or reduced rates of ongoing pregnancy or live birth among women of reproductive age. The current evidence remains limited and larger population studies are needed to further evaluate the effectiveness and safety of COVID-19 vaccination in pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

No direct funding was provided to support this work. M.P.R. was funded by the Medical Research Council Centre for Reproductive Health Grant No: MR/N022556/1. B.H.A.W. hold a personal development award from the National Institute of Health Research in the UK. All authors declare no conflict of interest.

REGISTRATION NUMBER

CRD42021289098.

Canine Coronavirus Infection Modulates the Biogenesis and Composition of Cell-Derived Extracellular Vesicles

Coronavirus (CoV) has persistently become a global health concern causing various diseases in a wide variety of hosts, including humans, birds, and companion animals. However, the virus-mediated responses in animal hosts have not been studied extensively due to pathogenesis complexity and disease developments. Extracellular vesicles (EVs) are widely explored in viral infections for their intercellular communication, nanocarrier, and immunomodulatory properties. We proposed that coronavirus hijacks the host exosomal pathway and modulates the EV biogenesis, composition, and protein trafficking in the host. In the present study, Crandell-Rees feline kidney (CRFK) cells were infected with canine coronavirus (CCoV) in an exosome-free medium at the multiplicity of infection (MOI) of 400 infectious units (IFU) at various time points. The cell viability was significantly decreased over time, as determined by the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Post-infection EVs were isolated, and transmission electron microscopy (TEM) showed the presence of small EVs (sEVs) after infection. NanoSight particle tracking analysis (NTA) revealed that EV sizes averaged between 100 and 200 nm at both incubation times; however, the mean size of infection-derived EVs was significantly decreased at 48 h when compared to uninfected control EVs. Quantitative analysis of protein levels performed by dot blot scanning showed that the expression levels of ACE-2, annexin-V, flotillin-1, TLR-7, LAMP, TNF-α, caspase-1, caspase-8, and others were altered in EVs after infection. Our findings suggested that coronavirus infection impacts cell viability, modulates EV biogenesis, and alters cargo composition and protein trafficking in the host, which could impact viral progression and disease development. Future experiments with different animal CoVs will provide a detailed understanding of host EV biology in infection pathogenesis and progression. Hence, EVs could offer a diagnostic and therapeutic tool to study virus-mediated host responses that could be extended to study the interspecies jump of animal CoVs to cause infection in humans.

Does mRNA COVID-19 vaccination in oocyte donors impact ovarian stimulation parameters or IVF outcomes for recipients?

RESEARCH QUESTION

What is the effect of mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in young oocyte donors in terms of ovarian response to stimulation, fertilization rate, embryo development and clinical outcomes in recipients?

DESIGN

This retrospective, multicentre cohort study evaluated 115 oocyte donors who had undergone at least two ovarian stimulation protocols (before and after complete SARS-CoV-2 vaccination) between November 2021 and February 2022. Comparisons were made of the primary outcomes of days of stimulation, total dose of gonadotrophins and laboratory performance in ovarian stimulation in oocyte donors before and after vaccination. A total of 136 cycles in matched recipients were analysed as secondary outcomes and, from those, 110 women received a fresh single-embryo transfer, with analysis of biochemical β-human chorionic gonadotrophin concentrations and rates of clinical pregnancy with heartbeat.

RESULTS

Longer stimulation was required in the post-vaccination than pre-vaccination group (10.31 ± 1.5 versus 9.51 ± 1.5 days; P < 0.001) along with higher gonadotrophin consumption (2453.5 ± 740 versus 2235.5 ± 615 IU; P < 0.001) with a similar starting dose of gonadotrophins in both groups. More oocytes were retrieved in the post-vaccination group (16.62 ± 7.1 versus 15.38 ± 7.0; P = 0.02). However, the number of metaphase II (MII) oocytes was similar between groups (pre-vaccination 12.61 ± 5.9 versus post-vaccination 13.01 ± 6.6; P = 0.39) and the ratio of MII/retrieved oocytes favoured the pre-vaccination group (0.83 ± 0.1 versus 0.77 ± 0.2 post-vaccination; P = 0.019). In recipients with a similar number of provided oocytes, the fertilization rate, total number of obtained blastocysts, number of top-quality blastocysts, and rates of biochemical pregnancy and clinical pregnancy with heartbeat were not significantly different between groups.

CONCLUSIONS

This study shows no adverse influence of mRNA SARS-CoV-2 vaccination on ovarian response in a young population.

Monocyte and Macrophage Function Diversity

In the last decade, there has been a tremendous revival of interest in monocyte and macrophages [...]

Endogenous Retroviruses (ERVs): Does RLR (RIG-I-Like Receptors)-MAVS Pathway Directly Control Senescence and Aging as a Consequence of ERV De-Repression?

Bi-directional transcription of Human Endogenous Retroviruses (hERVs) is a common feature of autoimmunity, neurodegeneration and cancer. Higher rates of cancer incidence, neurodegeneration and autoimmunity but a lower prevalence of autoimmune diseases characterize elderly people. Although the re-expression of hERVs is commonly observed in different cellular models of senescence as a result of the loss of their epigenetic transcriptional silencing, the hERVs modulation during aging is more complex, with a peak of activation in the sixties and a decline in the nineties. What is clearly accepted, instead, is the impact of the re-activation of dormant hERV on the maintenance of stemness and tissue self-renewing properties. An innate cellular immunity system, based on the RLR-MAVS circuit, controls the degradation of dsRNAs arising from the transcription of hERV elements, similarly to what happens for the accumulation of cytoplasmic DNA leading to the activation of cGAS/STING pathway. While agonists and inhibitors of the cGAS-STING pathway are considered promising immunomodulatory molecules, the effect of the RLR-MAVS pathway on innate immunity is still largely based on correlations and not on causality. Here we review the most recent evidence regarding the activation of MDA5-RIG1-MAVS pathway as a result of hERV de-repression during aging, immunosenescence, cancer and autoimmunity. We will also deal with the epigenetic mechanisms controlling hERV repression and with the strategies that can be adopted to modulate hERV expression in a therapeutic perspective. Finally, we will discuss if the RLR-MAVS signalling pathway actively modulates physiological and pathological conditions or if it is passively activated by them.

Effects of COVID-19 vaccination status, vaccine type, and vaccination interval on IVF pregnancy outcomes in infertile couples

Purpose

This study aimed to explore whether the coronavirus disease (COVID-19) vaccination of both partners in infertile couples, different types of COVID-19 vaccines, and the interval between complete vaccination and oocyte retrieval or embryo transfer (ET) affect the quality of embryos and pregnancy rates in in vitro fertilization (IVF).

Methods

This was a prospective cohort study, comprising 735 infertile couples conducted between December 6, 2021, and March 31, 2022, in a single university hospital-based IVF center. The patients were divided into different groups according to the vaccination status of both partners in infertile couples, type of vaccine, and interval between complete vaccination and IVF treatment. The embryo quality and pregnancy rates were compared among different groups.

Results

The results showed that embryo quality and pregnancy rates had no significant differences among different groups. The multivariate regression model showed that the vaccination status of both infertile couples, types of vaccines, and intervals had no significant effects on the clinical pregnancy rate.

Conclusions

The vaccination status of both partners in infertile couples, different types of vaccines, and time intervals have no effect on embryo quality and pregnancy rates in IVF. This is the first study to compare the vaccination status of both partners in infertile couples and the impact of different vaccine types on pregnancy rates and embryo quality in detail. Our findings provide evidence of vaccine safety for infertile couples wishing to undergo IVF treatment. This evidence is crucial for decision-making by clinicians and policymakers involved in IVF cycles.

Monocyte-Macrophage Lineage Cell Fusion

Cell fusion (fusogenesis) occurs in natural and pathological conditions in prokaryotes and eukaryotes. Cells of monocyte–macrophage lineage are highly fusogenic. They create syncytial multinucleated giant cells (MGCs) such as osteoclasts (OCs), MGCs associated with the areas of infection/inflammation, and foreign body-induced giant cells (FBGCs). The fusion of monocytes/macrophages with tumor cells may promote cancer metastasis. We describe types and examples of monocyte–macrophage lineage cell fusion and the role of actin-based structures in cell fusion.

Does mRNA SARS-CoV-2 vaccine in the follicular fluid impact follicle and oocyte performance in IVF treatments?

Problem

The COVID‐19 pandemic has many clinical manifestations. Rapid vaccine development raised concerns and speculations about future fertility outcomes and vaccine safety. We evaluated the effect of Pfizer‐BioNTech mRNA SARS‐CoV‐2 vaccine on IVF treatment, oocyte and embryo quality, and pregnancy outcomes.

Method of study

This prospective, observational cohort study was conducted in a referral IVF Unit, 3/2021‐5/2021. We aimed to recruit all women undergoing IVF/ICSI cycles from 3/1–4/30/2021, 2‐8 weeks after the second vaccination, and to analyze 50–60 samples in the 2‐month period. Patients were categorized according to serum antibody levels: positive for spike (S), positive for nucleotide (N), or negative for both. On the day of ovum pick‐up, follicular fluid and blood samples were analyzed for anti‐nucleotide (anti‐N) antibodies, and anti‐spike (anti‐S) antibodies, hormonal profile, C‐reactive protein (CRP) and other metabolic parameters.

Results

Of 59 women enrolled, 37 reported being vaccinated and 22 were not. We found 97% correlation between anti‐S and anti‐N in the blood and the follicular fluid. Follicular fluid was analyzed based on antibody categorization. All IVF treatment parameters in the follicular fluids and serum were comparable, except CRP was significantly elevated among patients with anti‐N antibodies (2.29 [1.42–6.08] vs. 4.11 [1.62–5.75] vs. 1.44 [.36–8.33]; p < .001). Pregnancy outcomes were comparable (44% vs. 33% vs. 50%; p = .97).

Conclusion

mRNA SARS‐CoV‐2 vaccine did not appear to affect treatment outcomes or ovarian reserves in the subsequent IVF cycle.

Virus interactions with the actin cytoskeleton-what we know and do not know about SARS-CoV-2

The actin cytoskeleton and actin-dependent molecular and cellular events are responsible for the organization of eukaryotic cells and their functions. Viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), depend on host cell organelles and molecular components for cell entry and propagation. Thus, it is not surprising that they also interact at many levels with the actin cytoskeleton of the host. There have been many studies on how different viruses reconfigure and manipulate the actin cytoskeleton of the host during successive steps of their life cycle. However, we know relatively little about the interactions of SARS-CoV-2 with the actin cytoskeleton. Here, we describe how the actin cytoskeleton is involved in the strategies used by different viruses for entry, assembly, and egress from the host cell. We emphasize what is known and unknown about SARS-CoV-2 in this regard. This review should encourage further investigation of the interactions of SARS-CoV-2 with cellular components, which will eventually be helpful for developing novel antiviral therapies for mitigating the severity of COVID-19.

Microorganisms as Shapers of Human Civilization, from Pandemics to Even Our Genomes: Villains or Friends? A Historical Approach

Universal history is characterized by continuous evolution, in which civilizations are born and die. This evolution is associated with multiple factors, among which the role of microorganisms is often overlooked. Viruses and bacteria have written or decisively contributed to terrible episodes of history, such as the Black Death in 14th century Europe, the annihilation of pre-Columbian American civilizations, and pandemics such as the 1918 Spanish flu or the current COVID-19 pandemic caused by the coronavirus SARS-CoV-2. Nevertheless, it is clear that we could not live in a world without these tiny beings. Endogenous retroviruses have been key to our evolution and for the regulation of gene expression, and the gut microbiota helps us digest compounds that we could not otherwise process. In addition, we have used microorganisms to preserve or prepare food for millennia and more recently to obtain drugs such as antibiotics or to develop recombinant DNA technologies. Due to the enormous importance of microorganisms for our survival, they have significantly influenced the population genetics of different human groups. This paper will review the role of microorganisms as "villains" who have been responsible for tremendous mortality throughout history but also as "friends" who help us survive and evolve.

Will Procreation Ever Be The Same After COVID-19?

Medically assisted procreation will never be the same again after this China Virus epidemic. With billions of lives being affected by this damaging global pandemic, medically assisted procreation services were not left unharmed with far-reaching consequences. New challenges are now emerging concerning COVID-19, such as associated reproductive implications and the consequences of assisted and natural procreation in the presence of acute SARS-CoV-2 infection and delayed consequences after patient recovery. There is a hypothesis that testicular damage and subsequent infertility may result following COVID-19 infection and the possibility of sexual transmission, as SARS-CoV-2 has been identified in the semen of infected patients. Vaccine hesitancy in young women planning pregnancies has been heightened because of the spread of misinformation on social media stating that COVID-19 vaccines will cause sterility in women. Reassuring data from accidental pregnancies that have occurred in the clinical trials of approved COVID-19 vaccines indicate that vaccination does not harm fertility or increase the rate of miscarriage. Scientists have quickly related to good tissue practices in vitro fertilization and a rethink is on about encouraging biopsies and focusing on safe vitrification protocols keeping in mind that ova, sperm, and embryos could be possible vectors for disease transmission with the limited research on the SARS-CoV-2 virus. Going ahead with segmented IVF without delay, freezing the generated embryos and pushing back the embryo transfer after the pandemic appears to be the best strategy at present. An international group of researchers have proposed a prognostic stratification of more vulnerable infertility cases in order to plan a progressive restart of worldwide fertility treatments.