17β-Estradiol, a potential ally to alleviate SARS-CoV-2 infection

Investigation of the potential effects of estrogen receptor modulators on immune checkpoint molecules

Immune checkpoints regulate the immune system response. Recent studies suggest that flavonoids, known as phytoestrogens, may inhibit the PD-1/PD-L1 axis. We explored the potential of estrogens and 17 Selective Estrogen Receptor Modulators (SERMs) as inhibiting ligands for immune checkpoint proteins (CTLA-4, PD-L1, PD-1, and CD80). Our docking studies revealed strong binding energy values for quinestrol, quercetin, and bazedoxifene, indicating their potential to inhibit PD-1 and CTLA-4. Quercetin and bazedoxifene, known to modulate EGFR and IL-6R alongside estrogen receptors, can influence the immune checkpoint functionality. We discuss the impact of SERMs on PD-1 and CTLA-4, suggesting that these SERMs could have therapeutic effects through immune checkpoint inhibition. This study highlights the potential of SERMs as inhibitory ligands for immune checkpoint proteins, emphasizing the importance of considering PD-1 and CTLA-4 inhibition when evaluating SERMs as therapeutic agents. Our findings open new avenues for cancer immunotherapy by exploring the interaction between various SERMs and immune checkpoint pathways.

SARS-CoV-2 immunity in animal models

The COVID-19 pandemic, which was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a worldwide health crisis due to its transmissibility. SARS-CoV-2 infection results in severe respiratory illness and can lead to significant complications in affected individuals. These complications encompass symptoms such as coughing, respiratory distress, fever, infectious shock, acute respiratory distress syndrome (ARDS), and even multiple-organ failure. Animal models serve as crucial tools for investigating pathogenic mechanisms, immune responses, immune escape mechanisms, antiviral drug development, and vaccines against SARS-CoV-2. Currently, various animal models for SARS-CoV-2 infection, such as nonhuman primates (NHPs), ferrets, hamsters, and many different mouse models, have been developed. Each model possesses distinctive features and applications. In this review, we elucidate the immune response elicited by SARS-CoV-2 infection in patients and provide an overview of the characteristics of various animal models mainly used for SARS-CoV-2 infection, as well as the corresponding immune responses and applications of these models. A comparative analysis of transcriptomic alterations in the lungs from different animal models revealed that the K18-hACE2 and mouse-adapted virus mouse models exhibited the highest similarity with the deceased COVID-19 patients. Finally, we highlighted the current gaps in related research between animal model studies and clinical investigations, underscoring lingering scientific questions that demand further clarification.

Mapping the Lipid Signatures in COVID-19 Infection: Diagnostic and Therapeutic Solutions

The COVID-19 pandemic ignited research centered around the identification of robust biomarkers and therapeutic targets. SARS-CoV-2, the virus responsible, hijacks the metabolic machinery of the host cells. It relies on lipids and lipoproteins of host cells for entry, trafficking, immune evasion, viral replication, and exocytosis. The infection causes host cell lipid metabolic remodelling. Targeting lipid-based processes is thus a promising strategy for countering COVID-19. Here, we review the role of lipids in the different steps of the SARS-CoV-2 pathogenesis and identify lipid-centric targetable avenues. We discuss lipidome changes in infected patients and their relevance as potential clinical diagnostic or prognostic biomarkers. We summarize the emerging direct and indirect therapeutic approaches for targeting COVID-19 using lipid-inspired approaches. Given that viral protein-targeted therapies may become less effective due to mutations in emerging SARS-CoV-2 variants, lipid-inspired interventions may provide additional and perhaps better means of combating this and future pandemics.

Sensitive detection of 17β-estradiol at a picomolar level using an aptamer-assisted liquid crystal-based optical sensor

A liquid crystal (LC)-based aptasensor was developed that can detect 17β-estradiol (E2) at the picomolar level. This aptasensor is based on competitive reactions of the aptamer that interacts with cetyl trimethyl ammonium bromide (CTAB) and E2 at the aqueous/LC interface. The long alkyl chain of CTAB anchored the 4-cyano-4'-pentylbiphenyl (5CB) to a homeotropic state and controls the local anchoring depending on the extent of electrostatic interaction with the aptamer. Upon addition of the aptamer solution to the CTAB-saturated LC layer, LCs change from dark to bright optical response. This is due to the perturbed orientation of 5CB at the aqueous/LC interface as a result of electrostatic attraction of the cationic group of CTAB and the phosphate group of the aptamer. The conformational change of the aptamer due to specific binding with E2 weakens the electrostatic attraction between CTAB and aptamer. When specific binding becomes relatively dominant, CTAB induces the orientation of LCs to the homeotropic state, resulting in a dark optical image observed. We also analyzed the change in the optical response of LCs according to the interfacial events and compared the grayscale values of the optical image for each concentration of E2 to determine the detection limit. Accordingly, the detection limit of the E2 sensor was found to be 3.1 pM (0.8 pg/ml) in Tris-buffered saline (TBS), and 6.8 pM (1.9 pg/ml) in human urine. The LC-based optical aptasensor was thus shown to be highly sensitive and selective with no requirement for complex analysis equipment.

A chronological review of COVID-19 case fatality rate and its secular trend and investigation of all-cause mortality and hospitalization during the Delta and Omicron waves in the United States: a retrospective cohort study

Introduction

Coronavirus disease 2019 (COVID-19) has caused more than 690 million deaths worldwide. Different results concerning the death rates of the Delta and Omicron variants have been recorded. We aimed to assess the secular trend of case fatality rate (CFR), identify risk factors associated with mortality following COVID-19 diagnosis, and investigate the risks of mortality and hospitalization during Delta and Omicron waves in the United States.

Methods

This study assessed 2,857,925 individuals diagnosed with COVID-19 in the United States from January 2020, to June 2022. The inclusion criterion was the presence of COVID-19 diagnostic codes in electronic medical record or a positive laboratory test of the SARS-CoV-2. Statistical analysis was bifurcated into two components, longitudinal analysis and comparative analysis. To assess the discrepancies in hospitalization and mortality rates for COVID-19, we identified the prevailing periods for the Delta and Omicron variants.

Results

Longitudinal analysis demonstrated four sharp surges in the number of deaths and CFR. The CFR was persistently higher in males and older age. The CFR of Black and White remained higher than Asians since January 2022. In comparative analysis, the adjusted hazard ratios for all-cause mortality and hospitalization were higher in Delta wave compared to the Omicron wave. Risk of all-cause mortality was found to be greater 14-30 days after a COVID-19 diagnosis, while the likelihood of hospitalization was higher in the first 14 days following a COVID-19 diagnosis in Delta wave compared with Omicron wave. Kaplan-Meier analysis revealed the cumulative probability of mortality was approximately 2-fold on day 30 in Delta than in Omicron cases (log-rank p < 0.001). The mortality risk ratio between the Delta and Omicron variants was 1.671 (95% Cl 1.615-1.729, log-rank p < 0.001). Delta also had a significantly increased mortality risk over Omicron in all age groups. The CFR of people aged above 80 years was extremely high as 17.33%.

Conclusion

Male sex and age seemed to be strong and independent risk factors of mortality in COVID-19. The Delta variant appears to cause more hospitalization and death than the Omicron variant.

Self-reported symptoms after COVID-19 vaccination. Distinct sex, age, and geographical outcomes in Lebanese and Italian cohorts

Following the COVID-19 discovery in December 2019, different vaccines were authorized in 2021 in Italy and Lebanon, but side effects and the impact of sex and age remained partly explored. We designed a web-based "Google Form" questionnaire to record self-reported systemic and local side effects up to 7 days after 1st and 2nd dose of the vaccine in two distinct Italian and Lebanese cohorts. Twenty-one questions in Italian and Arabic languages explored the prevalence and severity of 13 symptoms. Results were compared with respect to living country, timing, sex, and age classes. A total of 1,975 Italian subjects (age 42.9 ± SD16.8 years; 64.5% females) and 822 Lebanese subjects (age 32.5 ± SD15.9 years; 48.8% females) joined the study. The most common symptoms in both groups were injection site pain, weakness, and headache after the 1st and 2nd doses. The rate of post-vaccinal symptoms and the severity score were significantly higher in females than in males and progressively decreased with increasing age following both doses. We find that among two populations from the Mediterranean basin, the anti-COVID-19 vaccine generates mild age and sex-dependent adverse effects, with ethnic differences and prevalent symptoms rate and severity in females.

Innate and adaptive immunity to SARS-CoV-2 and predisposing factors

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), has affected all countries worldwide. Although some symptoms are relatively mild, others are still associated with severe and even fatal clinical outcomes. Innate and adaptive immunity are important for the control of SARS-CoV-2 infections, whereas a comprehensive characterization of the innate and adaptive immune response to COVID-19 is still lacking and the mechanisms underlying immune pathogenesis and host predisposing factors are still a matter of scientific debate. Here, the specific functions and kinetics of innate and adaptive immunity involved in SARS-CoV-2 recognition and resultant pathogenesis are discussed, as well as their immune memory for vaccinations, viral-mediated immune evasion, and the current and future immunotherapeutic agents. We also highlight host factors that contribute to infection, which may deepen the understanding of viral pathogenesis and help identify targeted therapies that attenuate severe disease and infection.

Immunological evaluation of young unvaccinated patients with Turner syndrome after COVID-19

OBJECTIVES

The X-chromosome contains the largest number of immune-related genes, which play a major role in COVID-19 symptomatology and susceptibility. Here, we had a unique opportunity to investigate, for the first time, COVID-19 outcomes in six unvaccinated young Brazilian patients with Turner syndrome (TS; 45, X0), including one case of critical illness in a child aged 10 years, to evaluate their immune response according to their genetic profile.

METHODS

A serological analysis of humoral immune response against SARS-CoV-2, phenotypic characterization of antiviral responses in peripheral blood mononuclear cells after stimuli, and the production of cytotoxic cytokines of T lymphocytes and natural killer cells were performed in blood samples collected from the patients with TS during the convalescence period. Whole exome sequencing was also performed.

RESULTS

Our volunteers with TS showed a delayed or insufficient humoral immune response to SARS-CoV-2 (particularly immunoglobulin G) and a decrease in interferon-γ production by cluster of differentiation (CD)4+ and CD8+ T lymphocytes after stimulation with toll-like receptors 7/8 agonists. In contrast, we observed a higher cytotoxic activity in the volunteers with TS than the volunteers without TS after phorbol myristate acetate/ionomycin stimulation, particularly granzyme B and perforin by CD8+ and natural killer cells. Interestingly, two volunteers with TS carry rare genetic variants in genes that regulate type I and III interferon immunity.

CONCLUSION

Following previous reports in the literature for other conditions, our data showed that patients with TS may have an impaired immune response against SARS-CoV-2. Furthermore, other medical conditions associated with TS could make them more vulnerable to COVID-19.

Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies

The fight against coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection is still raging. However, the pathophysiology of acute and post-acute manifestations of COVID-19 (long COVID-19) is understudied. Endothelial cells are sentinels lining the innermost layer of blood vessel that gatekeep micro- and macro-vascular health by sensing pathogen/danger signals and secreting vasoactive molecules. SARS-CoV-2 infection primarily affects the pulmonary system, but accumulating evidence suggests that it also affects the pan-vasculature in the extrapulmonary systems by directly (via virus infection) or indirectly (via cytokine storm), causing endothelial dysfunction (endotheliitis, endothelialitis and endotheliopathy) and multi-organ injury. Mounting evidence suggests that SARS-CoV-2 infection leads to multiple instances of endothelial dysfunction, including reduced nitric oxide (NO) bioavailability, oxidative stress, endothelial injury, glycocalyx/barrier disruption, hyperpermeability, inflammation/leukocyte adhesion, senescence, endothelial-to-mesenchymal transition (EndoMT), hypercoagulability, thrombosis and many others. Thus, COVID-19 is deemed as a (micro)vascular and endothelial disease. Of translational relevance, several candidate drugs which are endothelial protective have been shown to improve clinical manifestations of COVID-19 patients. The purpose of this review is to provide a latest summary of biomarkers associated with endothelial cell activation in COVID-19 and offer mechanistic insights into the molecular basis of endothelial activation/dysfunction in macro- and micro-vasculature of COVID-19 patients. We envisage further development of cellular models and suitable animal models mimicking endothelial dysfunction aspect of COVID-19 being able to accelerate the discovery of new drugs targeting endothelial dysfunction in pan-vasculature from COVID-19 patients.

The relationship between sex steroids (E2, progesterone, and AMH) levels and severity and fatality of COVID-19: A systematic review

Sex steroids are powerful modulators of the immune system and they may affect the immune response and inflammatory consequences of COVID-19. This systematic review aims to explore the impact of sex steroids on COVID-19 mortality and complications. We looked up the keywords of the study in Scopus, PubMed, and Web of Science. All related original articles published in English, as of October 16, 2021, were reviewed to be included in our research. Concerns regarding the effect of sex hormones on COVID-19, eight full texts have been identified for the conclusion. In these studies, the relationship between estradiol and COVID-19 mortality has been mentioned. The most significant findings were the higher COVID-19 mortality rate in men, compared to women; also, in menopausal women compared to younger women and who received estradiol. In two studies, oral contraceptive pills had a protective effect on the morbidity of SARS-CoV-2 infection. In a randomized controlled trial, subcutaneous injection of progesterone in hospitalized men significantly reduced their symptoms and need for oxygen therapy. Hormone replacement therapy was positively associated with reducing COVID-19 symptoms. Although the results were insufficient for a conclusion, this study represents estrogen as an appropriate pharmacological method for preventing and diminishing the inflammation related to COVID-19 disease. However, future prospective studies and clinical trials are needed to clarify and approve this protective effect.

Androgens' Role in Severity and Mortality Rates of COVID-19

By the end of December 2019 new corona virus began to spread from Wuhan, China and caused a worldwide pandemic. COVID-19 deaths and prevalence represented sex discrepant patterns with higher rate of deaths and infection in males than females which could be justified by androgen-mediated mechanisms. This review aimed to assess the role of androgens in COVID-19 severity and mortality. Androgens increase expressions of Type II transmembrane Serine Protease (TMPRSS2) and Angiotensin Converting Enzyme 2 (ACE2), which both facilitate new corona virus entry into host cell and their expression is higher in young males than females. According to observational studies, prevalence of COVID-19 infections and deaths was more in androgenic alopecic patients than patients without androgenic alopecia. The COVID-19 mortality rates in aged men (>60 years) were substantially higher than aged females and even young males caused by high inflammatory activities such as cytokine storm due to hypogonadism in this population. Use of anti-androgen and TMPRSS2 inhibitor drugs considerably modified COVID-19 symptoms. Androgen deprivation therapy also improved COVID-19 symptoms in prostate cancer: overall the role of androgens in severity of COVID-19 and its associated mortality seemed to be very important. So, more studies in variety of populations are required to define the absolute role of androgens.

Overexpression of estrogen receptor GPER1 and G1 treatment reduces SARS-CoV-2 infection in BEAS-2B bronchial cells

Gender-bias in COVID-19 severity has been suggested by clinical data. Experimental data in cell and animal models have demonstrated the role of sex hormones, particularly estrogens, in viral infections such as in COVID-19. SARS-CoV-2 uses ACE2 as a receptor to recognize host cells, and the protease TMPRSS2 for priming the Spike protein, facilitating virus entry into cells. However, the involvement of estrogenic receptors in SARS-CoV-2 infection are still being explored. Thus, in order to investigate the role of estrogen and its receptors in COVID-19, the estrogen receptors ERα, ERβ and GPER1 were overexpressed in bronchial BEAS-2B cell, and then infected with SARS-CoV-2. Interestingly, the levels of ACE2 and TMPRSS2 mRNA were higher in SARS-CoV-2-infected cells, but no difference was observed in cells with estrogen receptors overexpression. GPER1 can be involved in virus infection or replication, since its higher levels reduces SARS-CoV-2 load. On the other hand, pharmacological antagonism of GPER1 enhanced viral load. Those data suggest that GPER1 has an important role in SARS-CoV-2 infection.

Biofunctional roles of estrogen in coronavirus disease 2019: Beyond a steroid hormone

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), epidemic poses a major global public health threat with more than one million daily new infections and hundreds of deaths. To combat this global pandemic, efficient prevention and management strategies are urgently needed. Together with the main characteristics of COVID-19, impaired coagulation with dysfunctions of the immune response in COVID-19 pathophysiology causes high mortality and morbidity. From recent clinical observations, increased expression of specific types of estrogen appears to protect patients from SARS-CoV-2 infection, thereby, reducing mortality. COVID-19 severity is less common in women than in men, particularly in menopausal women. Furthermore, estrogen levels are negatively correlated with COVID-19 severity and mortality. These findings suggest that estrogen plays a protective role in the pathophysiology of COVID-19. In this review, we discuss the potential roles of estrogen in blocking the SARS-CoV-2 from invading alveolar cells and replicating, and summarize the potential mechanisms of anti-inflammation, immune modulation, reactive oxygen species resistance, anti-thrombosis, vascular dilation, and vascular endothelium protection. Finally, the potential therapeutic effects of estrogen against COVID-19 are reviewed. This review provides insights into the role of estrogen and its use as a potential strategy to reduce the mortality associated with COVID-19, and possibly other viral infections and discusses the possible challenges and pertinent questions.

Premenopausal and postmenopausal women during the COVID-19 pandemic

The current global COVID-19 mortality rate is estimated to be around 3.4%; however, it is dependent on age, sex, and comorbidities. Epidemiological evidence shows gender disparities in COVID-19 severity and fatality, with non-menopausal females having milder severity and better outcomes than age-matched males. However, the difference vanishes when comparing postmenopausal women with age-matched men. It has been suggested that, to some extent, this is due to the protective role of female hormones, such as anti-Müllerian hormone and oestradiol (E2), in non-menopausal women. Oestrogens have been hypothesized to be crucial in modulating viral infection and the progression of the disease via an action on immune/inflammatory responses and angiotensin-converting enzyme type 2 expression. Hence, the most likely explanation is that, because the levels of oestrogen in females after menopause decrease, oestrogen no longer offers a beneficial effect as seen in younger females. The COVID-19 pandemic has highlighted the serious negative effects arising from the state of E2 deficiency. Therefore, hormone replacement therapy gains further support as the damaging effect of the decline in ovarian function affects many biological systems, and recently with the COVID-19 pandemic, oestrogen's vital role within the immune system has become quite clear. However, additional clinical investigations regarding hormone replacement therapy are urgently needed to further verify the protective and therapeutic effects of E2 on menopausal women with COVID-19.

The immune response to COVID-19: Does sex matter?

The coronavirus disease 2019 (COVID-19) pandemic has created unprecedented challenges worldwide. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and has a complex interaction with the immune system, including growing evidence of sex-specific differences in the immune response. Sex-disaggregated analyses of epidemiological data indicate that males experience more severe symptoms and suffer higher mortality from COVID-19 than females. Many behavioural risk factors and biological factors may contribute to the different immune response. This review examines the immune response to SARS-CoV-2 infection in the context of sex, with emphasis on potential biological mechanisms explaining differences in clinical outcomes. Understanding sex differences in the pathophysiology of SARS-CoV-2 infection will help promote the development of specific strategies to manage the disease.

Examining Male Predominance of Severe COVID-19 Outcomes: A Systematic Review

Although not universal, many epidemiological data sources signal that a higher proportion of males than females with confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections have adverse outcomes, such as intensive care unit (ICU) admission and death. Though likely multifactorial, the various hypotheses that have been proposed as underlying factors behind this trend are related to greater smoking prevalence among males, testosterone (T) deficiency causing an inflammatory storm, androgen-driven pathogenesis of SARS-CoV-2, a protective effect of estrogen in females, and inborn errors of cytokine immunity. This review aims at examining the evidence and at assessing the likelihood that the factors being investigated are contributory to the reported trend of male predominance of severe COVID-19 cases. Sources were obtained using the PubMed database and were selected based on their relevance to one of the primary hypotheses attempting to explain the strong male sex bias of severe SARS-CoV-2 infections. Emphasis was placed on meta-analyses and population-based studies. Sources are current through February 22, 2022. A severe COVID-19 case or outcome is defined in this review as a progression of the SARS-CoV-2 virus that results in either admission to an ICU for management of symptoms and clinical stabilization or which leads to death. Although the trend of male predominance of severe COVID-19 cases is likely multifactorial, the hypothesis of T deficiency causing an inflammatory storm has support from many studies with limited conflicting evidence. An inborn error in cytokine immunity is also well supported, but it needs more studies to add support to the hypothesis. The immunologic protective effect of estrogen is supported by multiple studies, but it also has conflicting evidence. It appears less likely that the trend is caused solely by an increased prevalence of smoking among males or an androgen-driven pathogenesis, based on the extent of conflicting evidence.

Potential of Endogenous Oxytocin in Endocrine Treatment and Prevention of COVID-19

Coronavirus disease 2019 or COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a significant threat to the health of human beings. While wearing mask, maintaining social distance and performing self-quarantine can reduce virus spreading passively, vaccination actively enhances immune defense against COVID-19. However, mutations of SARS-CoV-2 and presence of asymptomatic carriers frustrate the effort of completely conquering COVID-19. A strategy that can reduce the susceptibility and thus prevent COVID-19 while blocking viral invasion and pathogenesis independent of viral antigen stability is highly desirable. In the pathogenesis of COVID-19, endocrine disorders have been implicated. Correspondingly, many hormones have been identified to possess therapeutic potential of treating COVID-19, such as estrogen, melatonin, corticosteroids, thyroid hormone and oxytocin. Among them, oxytocin has the potential of both treatment and prevention of COVID-19. This is based on oxytocin promotion of immune-metabolic homeostasis, suppression of inflammation and pre-existing comorbidities, acceleration of damage repair, and reduction of individuals' susceptibility to pathogen infection. Oxytocin may specifically inactivate SARS-COV-2 spike protein and block viral entry into cells via angiotensin-converting enzyme 2 by suppressing serine protease and increasing interferon levels and number of T-lymphocytes. In addition, oxytocin can promote parasympathetic outflow and the secretion of body fluids that could dilute and even inactivate SARS-CoV-2 on the surface of cornea, oral cavity and gastrointestinal tract. What we need to do now is clinical trials. Such trials should fully balance the advantages and disadvantages of oxytocin application, consider the time- and dose-dependency of oxytocin effects, optimize the dosage form and administration approach, combine oxytocin with inhibitors of SARS-CoV-2 replication, apply specific passive immunization, and timely utilize efficient vaccines. Meanwhile, blocking COVID-19 transmission chain and developing other efficient anti-SARS-CoV-2 drugs are also important. In addition, relative to the complex issues with drug applications over a long term, oxytocin can be mobilized through many physiological stimuli, and thus used as a general prevention measure. In this review, we explore the potential of oxytocin for treatment and prevention of COVID-19 and perhaps other similar pathogens.

Basic mechanisms of SARS-CoV-2 infection. What endocrine systems could be implicated?

Although SARS-CoV-2 viral attacks starts by the interaction of spike protein (S Protein) to ACE2 receptor located at the cell surface of respiratory tract and digestive system cells, different endocrine targets, endocrine organs and metabolic conditions are of fundamental relevance for understanding disease progression and special outcomes, in particular those of fatal consequences for the patient. During pandemic, moreover, a specific phenotype of COVID-19 metabolic patient has been described, characterized by being at particular risk of worse outcomes. In the present paper we describe the mechanism of viral interaction with endocrine organs, emphasizing the specific endocrine molecules of particular relevance explaining COVID-19 disease evolution and outcomes.

The Impact of the SARS-CoV-2 Pandemic on Reproduction, Sexual Function and Behaviors: A Review of the Main Trends and Findings

Objective: This review sought to describe the main trends and findings on the SARS-CoV-2 and the pandemic's effect on reproduction (i.e., effects on fertility, reproductive tissue, pregnancy, vertical and sexual transmission) and sexual function and behaviors. Methods: A review was conducted on studies assessing these variables through the Scopus and PubMed databases between the years 2019-2021. Results: Results showed SARS-CoV-2 pandemic and social distancing measures have affected-and in some cases not-different aspects of people's reproductive function, sexual function and behaviors. Conclusions: Suggestions are offered for researchers and professionals focused on future research and clinical practice.

Immune mechanisms associated with sex-based differences in severe COVID-19 clinical outcomes

Background

Although biological males and females are equally likely to become infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), evidence has mounted that males experience higher severity and fatality compared to females.

Main

The objective of this review is to examine the existing literature on biological mechanisms underlying sex-based differences that could contribute to SARS-CoV-2 infection clinical outcomes. Sex-based differences in immunologic response and hormonal expression help explain the differences in coronavirus disease 2019 (COVID-19) outcomes observed in biological males and females. X inactivation facilitates a robust immune response to COVID-19 in females, who demonstrate a more profound antibody response and faster recovery when compared to males. Low testosterone levels also help explain the dysregulated inflammatory response and poor outcomes observed in some males with COVID-19. Gender differences in health expression and behaviors further compound these observed differences.

Conclusion

Understanding the biology of sex-based differences in COVID-19 severity and mortality could help inform preventative measures, treatment decisions, and development of personalized, sex-specific therapies.

Although most COVID-19 patients develop only mild disease, some mount a pronounced inflammatory response that results in severe pneumonia, respiratory failure, and death.

Male sex is a known risk factor for severe outcomes in COVID-19.

Biological sex-based differences in COVID-19 severity and mortality are influenced by genetic and hormonal differences at the cellular and immunologic level.

Biological sex-based differences are further complicated by environmental factors, namely social and cultural norms, that define gender roles which impact risk of infection and severe outcomes.

Understanding sex-based differences in COVID-19 outcomes will help inform clinical decision algorithms and treatment strategies to optimize the care of COVID-19 patients.

COVID-19 Drug Repurposing: A Network-Based Framework for Exploring Biomedical Literature and Clinical Trials for Possible Treatments

BACKGROUND

With the Coronavirus becoming a new reality of our world, global efforts continue to seek answers to many questions regarding the spread, variants, vaccinations, and medications. Particularly, with the emergence of several strains (e.g., Delta, Omicron), vaccines will need further development to offer complete protection against the new variants. It is critical to identify antiviral treatments while the development of vaccines continues. In this regard, the repurposing of already FDA-approved drugs remains a major effort. In this paper, we investigate the hypothesis that a combination of FDA-approved drugs may be considered as a candidate for COVID-19 treatment if (1) there exists an evidence in the COVID-19 biomedical literature that suggests such a combination, and (2) there is match in the clinical trials space that validates this drug combination.

METHODS

We present a computational framework that is designed for detecting drug combinations, using the following components (a) a Text-mining module: to extract drug names from the abstract section of the biomedical publications and the intervention/treatment sections of clinical trial records. (b) a network model constructed from the drug names and their associations, (c) a clique similarity algorithm to identify candidate drug treatments.

RESULT AND CONCLUSIONS

Our framework has identified treatments in the form of two, three, or four drug combinations (e.g., hydroxychloroquine, doxycycline, and azithromycin). The identifications of the various treatment candidates provided sufficient evidence that supports the trustworthiness of our hypothesis.

An antibody-based proximity labeling map reveals mechanisms of SARS-CoV-2 inhibition of antiviral immunity

The global epidemic caused by the coronavirus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has resulted in the infection of over 200 million people. To extend the knowledge of interactions between SARS-CoV-2 and humans, we systematically investigate the interactome of 29 viral proteins in human cells by using an antibody-based TurboID assay. In total, 1,388 high-confidence human proximal proteins with biotinylated sites are identified. Notably, we find that SARS-CoV-2 manipulates the antiviral and immune responses. We validate that the membrane protein ITGB1 associates angiotensin-converting enzyme 2 (ACE2) to mediate SARS-CoV-2 entry. Moreover, we reveal that SARS-CoV-2 proteins inhibit activation of the interferon pathway through the mitochondrial protein mitochondrial antiviral-signaling protein (MAVS) and the methyltransferase SET domain containing 2, histone lysine methyltransferase (SETD2). We propose 111 potential drugs for the clinical treatment of coronavirus disease 2019 (COVID-19) and identify three compounds that significantly inhibit the replication of SARS-CoV-2. The proximity labeling map of SARS-CoV-2 and humans provides a resource for elucidating the mechanisms of viral infection and developing drugs for COVID-19 treatment.

Repurposing the estrogen receptor modulator raloxifene to treat SARS-CoV-2 infection

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) necessitates strategies to identify prophylactic and therapeutic drug candidates to enter rapid clinical development. This is particularly true, given the uncertainty about the endurance of the immune memory induced by both previous infections or vaccines, and given the fact that the eradication of SARS-CoV-2 might be challenging to reach, given the attack rate of the virus, which would require unusually high protection by a vaccine. Here, we show how raloxifene, a selective estrogen receptor modulator with anti-inflammatory and antiviral properties, emerges as an attractive candidate entering clinical trials to test its efficacy in early-stage treatment COVID-19 patients.

Analysis of the Role of Female Hormones During Infection by COVID-19

Women have metabolic, immunological, and genetic variables that ensure more protection from coronavirus infection. However, the indication of treatment for several pathologies and contraception is determined by hormones that have adverse effects and raise doubts about their use during the COVID-19 pandemic. Therefore, the present study searches women specificities and the relation between female sexual hormones and COVID-19, and reports the main recommendations in this background. To this end, a review of the literature was conducted in the main databases, auxiliary data sources, and official websites. Therefore, considering the hypercoagulability status of COVID-19, the debate about the use of contraceptives due to the relative risk of thromboembolic effects that they impose arises. However, the current available evidence, as well as the recommendations of main health organs around the world, demonstrate that the use of hormonal contraceptives must be maintained during the pandemic.

Final Results of a Randomized, Placebo-Controlled, Two-Arm, Parallel Clinical Trial of Proxalutamide for Hospitalized COVID-19 Patients: A Multiregional, Joint Analysis of the Proxa-Rescue AndroCoV Trial

Background The role of androgens on COVID-19 is well established. Proxalutamide is a second-generation, non-steroidal antiandrogen (NSAA) with the highest antiandrogen potency among NSAAs and concurrent regulation of angiotensin-converting enzyme 2 (ACE2) expression and inflammatory response. Proxalutamide has been demonstrated to be effective to prevent hospitalizations in early COVID-19 in randomized clinical trials (RCTs). Conversely, in hospitalized COVID-19 patients, preliminary results from two different arms of an RCT (The Proxa-Rescue AndroCoV Trial) also demonstrated a reduction in all-cause mortality. This study aims to report the final, joint results of the two arms (North arm and South arm) of the Proxa-Rescue AndroCoV trial of the two arms (North and South arms) combined, and to evaluate whether COVID-19 response to proxalutamide was consistent across different regions (Northern Brazil and Southern Brazil). Materials and methods Upon randomization, hospitalized COVID-19 patients received either proxalutamide 300mg/day or placebo for 14 days, in addition to usual care, in a proxalutamide:placebo ratio of 1:1 in the North arm and 4:1 in the South arm (ratio was modified due to preliminary report of high drug efficacy). Datasets of the South and North arms were combined, and statistical analysis was performed for the overall study population. Proxalutamide was compared to placebo group for 14-day and 28-day recovery (discharge alive from the hospital) and mortality rates, and overall and post-randomization hospitalization stay. Results of proxalutamide and placebo groups were also compared between the North and South arms. Analysis was also performed stratified by sex and baseline WHO COVID Ordinary Score. Results A total of 778 subjects were included (645 from the North, 317 from the proxalutamide group and 328 from the placebo group; 133 from the South arm, 106 from the proxalutamide group and 27 from the placebo group). Recovery rate was 121% higher in proxalutamide than placebo group at day 14 [81.1% vs 36.6%; Recovery ratio (RecR) 2.21; 95% confidence interval (95% CI), 1.92-2.56; p<0.0001], and 81% higher at day 28 (98.1% vs 47.6%; RecR, 1.81; 95% CI, 1.61-2.03; p<0.0001). All-cause mortality rate was 80% lower in proxalutamide than placebo group at Day 14 [8.0% vs 39.2%; Risk ratio (RR), 0.20; 95% CI, 0.14-0.29; p<0.0001], and 78% lower at Day 28 (10.6% vs 48.2%; RR, 0.22; 95% CI 0.16-0.30). Post-randomization time-to-discharge was shorter in proxalutamide [median, 5 days; interquartile range (IQR), 3-8] than placebo group (median, 9 days; IQR, 6-14) (p<0.0001). Results were statistically similar between North and South arms for all measured outcomes. Males and females presented similar results in all outcomes. Patients that did not require oxygen use (scores 3 and 4) did not present statistically significant improvement in recovery and mortality rates, whereas scores 5 and 6 presented significant improvements in all outcomes (p<0.0001 for all). Conclusion Proxalutamide increased recovery rate, reduced mortality rate and shortened hospital stay in hospitalized COVID-19 patients. Results were similar between the two different arms, providing further consistency for the efficacy of proxalutamide when used in late-stage COVID-19.

The role of estradiol in the immune response against COVID-19

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the pathogen agent causing coronavirus disease (COVID)-19, which was declared a global pandemic in 2020. The spike protein of this virus and the angiotensin-converter enzyme (ACE)-2 in host cells in humans play a vital role in infection and in COVID-19 pathogenesis. Estradiol is known to modulate the actions of immune cells, and, therefore, the antiviral mechanisms of these cells could also be modified by this hormone stimulus. Even though estradiol is not considered a protective factor, evidence shows that women with high levels of this hormone have a lower risk of developing severe symptoms and an even a lower incidence of death. Understanding the mechanism of action of estradiol with regard to viral infections and COVID-19 is essential for the improvement of therapeutic strategies. This review aims to describe the effects that estradiol exerts on immune cells during viral infections and COVID-19.

COVID-19, gender and estroprogestins, what do we know?

The new coronavirus disease-19 (COVID-19) pandemic has rapidly spread all around the world, eliciting many questions and doubts about the pathogenesis of the disease and treatment. Mortality has been related to a prothrombotic state. Risk factors for the infection and for severe forms of COVID-19 have still to be defined. According to data collected, women appear to be less prone to severe forms of the disease and their mortality was lower than for men. The role of female hormones in the modulation of inflammation may be the reason behind this gender gap.Considering the prothrombotic state activated by the virus, hormone therapies have been placed under investigation as possible increasing risk factors for severe forms. Moreover, new vaccines and their rare thrombotic side effects have increased the concern about this issue.The goal of this review is to go over the mechanisms that lead up to thrombosis during COVID-19, trying to explain the possible reasons why women seem to be naturally protected. The expert opinions about whether to continue/discontinue hormonal therapies are reviewed. Moreover, available data about the so-called 'vaccine induced immune thrombotic thrombocytopaenia' caused by vaccines against COVID-19 are discussed.

Sensitive to Infection but Strong in Defense-Female Sex and the Power of Oestradiol in the COVID-19 Pandemic

The incidence of SARS-CoV2 infections is around 15% higher in premenopausal women compared to age matched men, yet the fatality rate from COVID-19 is significantly higher in men than women for all age strata. Sex differences have also been observed in recent epidemics including severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), with SARS-CoV 2 virus infection sex differences appear more dramatic. The regulation and expression of the angiotensin converting enzyme 2 (ACE2) is the key for this special coronavirus SARS-CoV-2 to enter the cell. 17β-oestradiol increases expression level and activity of angiotensin converting enzyme-2 (ACE2) and the alternative signaling pathway of Ang II via the angiotensin II receptor type II (AT2R) and the Mas receptor is more dominant in female sex than in male sex. Maybe a hint to explain the higher infection risk in women. The same hormonal milieu plays a major role in protecting women where morbidity and mortality are concerned, since the dominant female hormone, oestradiol, has immune-modulatory properties that are likely to be protective against virus infections. It is also known that the X chromosome contains the largest number of immune-related genes, potentially conferring an advantage to women in efficient immune responsiveness. Lifestyle factors are also likely to be contributory. Premenopausal women could possibly face higher exposure to infection (hence higher infection rates) because economic conditions are often less favorable for them with less opportunity for home office work because of jobs requiring mandatory attendance. Due to the additional task of childcare, it is likely that contact times with other people will be longer. Women generally make healthier lifestyle choices, thus reducing the disease burden that confers high risk of mortality in COVID-19 infected men. This narrative review aims to present key concepts and knowledge gaps on the effects of oestrogen associated with SARS-CoV2 infection and COVID-19 disease.

17β-estradiol modulates the expression of hormonal receptors on THP-1 T. gondii-infected macrophages and monocytes in an AKT and ERK-dependent manner

Toxoplasma gondii (T. gondii) is a parasite common in pregnancy. Monocytes and macrophages are a significant immunologic barrier against T. gondii by boosting up inflammation. This outcome is highly regulated by signaling pathways such as MAPK (ERK1/2) and PI3K (AKT), necessary in cell growth and proliferation. It may be associated with the hormonal receptors' modulation by T. gondii (Estrogen Receptor (ER)-α, ERβ, G Protein-coupled ER (GPER), and Prolactin Receptor (PRLR)), as previously reported by our research group. 17β-estradiol also activates MAPK and PI3K; however, its combined effect in THP-1 monocytes and macrophages, infected with T. gondii, has not yet been evaluated. This study aimed to evaluate the combined effect of 17β-estradiol in the activation of signaling pathways using a model of THP-1 monocytes and macrophages infected with T. gondii. THP-1 monocytes were cultured and differentiated into macrophages. Inhibition of AKT and ERK1/2 was performed with specific inhibitors. Stimuli were performed with 17β-estradiol (10 nM), T. gondii (20,000 tachyzoites), and both conditions for 48 h. Proteins were extracted and quantified, and Western Blot assays were performed. 17β-estradiol performed activation of ERK1/2 and AKT in T. gondii-infected macrophages. 17β-estradiol modulated the expression of hormonal receptors in infected cells: increases the PRLR and PrgR in T. gondii-infected macrophages and decreases the PRLR and ERα in T. gondii-infected monocytes. As for GPER, its expression is abolished by T. gondii, and 17β-estradiol cannot restore it. Finally, the blockage of ERK and AKT pathways modified the expression of hormonal receptors. In conclusion, 17β-estradiol modifies the receptors of T. gondii-infected THP1 macrophages and monocytes in an ERK/AKT dependent manner.

Thrombotic Adverse Events Reported for Moderna, Pfizer and Oxford-AstraZeneca COVID-19 Vaccines: Comparison of Occurrence and Clinical Outcomes in the EudraVigilance Database

Vaccination against COVID-19 is the cornerstone of controlling and mitigating the ongoing pandemic. Thrombotic adverse events linked to Moderna, Pfizer and the Oxford-AstraZeneca vaccine have been documented and described as extremely rare. While the Oxford-AstraZeneca vaccine has received much of the attention, the other vaccines should not go unchallenged. This study aimed to determine the frequency of reported thrombotic adverse events and clinical outcomes for these three COVID-19 vaccines, namely, Moderna, Pfizer and Oxford-AstraZeneca. A retrospective descriptive analysis was conducted of spontaneous reports for Moderna, Pfizer and Oxford-AstraZeneca COVID-19 vaccines submitted to the EudraVigilance database in the period from 17 February to 14 June 2021. There were 729,496 adverse events for the three vaccines, of which 3420 were thrombotic, mainly Oxford-AstraZeneca (n = 1988; 58.1%) followed by Pfizer (n = 1096; 32.0%) and Moderna (n = 336; 9.8%). As serious adverse events, there were 705 reports of pulmonary embolism for the three vaccines, of which 130 reports (18.4%) were for Moderna, 226 reports (32.1%) for Pfizer and 349 (49.5%) for Oxford-AstraZeneca vaccines. The occurrence of pulmonary embolism is significantly associated with a fatal outcome (p ≤ 0.001). Sixty-three fatalities were recorded (n = 63/3420; 1.8%), of which Moderna (n = 6), Pfizer (n = 25) and Oxford-AstraZeneca (n = 32).

Killing Two Birds with One Stone by Administration of Soluble ACE2: A Promising Strategy to Treat Both Cardiovascular Diseases and SARS-CoV-2 Infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) enters host cells mainly by the angiotensin converting enzyme 2 (ACE2) receptor, which can recognize the spike (S) protein by its extracellular domain. Previously, recombinant soluble ACE2 (sACE2) has been clinically used as a therapeutic treatment for cardiovascular diseases. Recent data demonstrated that sACE2 can also be exploited as a decoy to effectively inhibit the cell entry of SARS-CoV-2, through blocking SARS-CoV-2 binding to membrane-anchored ACE2. In this study, we summarized the current findings on the optimized sACE2-based strategies as a therapeutic agent, including Fc fusion to prolong the half-life of sACE2, deep mutagenesis to create high-affinity decoys for SARS-CoV-2, or designing the truncated functional fragments to enhance its safety, among others. Considering that COVID-19 patients are often accompanied by manifestations of cardiovascular complications, we think that administration of sACE2 in COVID-19 patients may be a promising therapeutic strategy to simultaneously treat both cardiovascular diseases and SARS-CoV-2 infection. This review would provide insights for the development of novel therapeutic agents against the COVID-19 pandemic.

Estradiol and COVID-19: Does 17-Estradiol Have an Immune-Protective Function in Women Against Coronavirus?

Objective: Female sex hormones have a pro-inflammatory effect, which may help to minimize inflammation. Estrogen's immunoregulatory properties play a significant role in the bi-directional neuroendocrine-immune activity in females. As a result, sex hormones can play a role in men's high mortality rate from coronavirus-2019 (COVID-19). It is aimed to clarify the role of 17-estradiol (E2) in the battle against COVID-19.

Materials and methods: Until April 2021, a study on PubMed was performed. COVID-19, 17-estradiol (E2), immunoregulatory properties, pregnancy, menopausal symptoms, hormonal therapy, ER/ expression on immune cells, and mortality were some of the concepts used in the search.

Results: Regulation of pro-inflammatory immune processes against COVID-19 appears to be associated with increased immune function (pro-inflammatory), anti-inflammatory regulation, and antiviral defense. Women with a severe coronavirus infection had higher serum IgG antibody levels than men, and their IgG production was faster in the early stages of infection. 17-estradiol (E2) levels of blood will increase by 100-fold during pregnancy. COVID-19 in pregnant women had a 15-fold lower mortality rate than other women. While menopause replacement therapy (MRT) for pre/post-menopausal women and its effectiveness in reducing COVID-19 infection is debatable.

Conclusion: MRT may be considered as a viable treatment option for pre/post-menopause women with coronavirus, referring to the fact that sex hormones reduce inflammatory responses and modulate ACE2 expression. The task's difficulty and achieving the desired outcome seem to be challenging.

Is there a common pathophysiological mechanism between COVID-19 and depression?

COVID-19 is a disease caused by SARS-CoV-2 and was initially considered to cause serious damage to the respiratory system. Over time, it has been found to affect other organs due to its ability to bind to the ACE2 receptor (type 2 angiotensin-converting enzyme), which can be found in various tissues, including the central nervous system. In addition, a large formation of pro-inflammatory cytokines responsible for various lesions was observed during the evolution of this disease. Our objective was to demonstrate the molecular mechanisms involved in the infection that may demonstrate the relationship between COVID-19 and the development of depressive conditions. Based on the main medical databases (LiLacs, SciELO, Bireme, Scopus, EBSCO, and PubMed) and using the terms 'coronavirus infections' AND 'Inflammation' AND 'depression' AND 'cytokines', we conducted an integrative review of articles published in 2020. Considering this stage of Covid-19 and the inflammatory component of depression, this review showed a relationship between these two conditions based on common pathophysiological mechanisms indicating possible depressive disorders in surviving patients, especially in the most severe cases. The role of inflammatory cytokines and the presence of ACE-2 receptors on the cell surface appear to be the common pathophysiological mechanism between COVID-19 and depression.

Coronary microvascular dysfunction pathophysiology in COVID-19

Recently, accumulating evidence has highlighted the role of endothelial dysfunction in COVID-19 progression. Coronary microvascular dysfunction (CMD) plays a pivotal role in cardiovascular disease (CVD) and CVD-related risk factors (eg, age, gender, hypertension, diabetes mellitus, and obesity). Equally, these are also risk factors for COVID-19. The purpose of this review was to explore CMD pathophysiology in COVID-19, based on recent evidence. COVID-19 mechanisms were reviewed in terms of imbalanced renin-angiotensin-aldosterone-systems (RAAS), systemic inflammation and immune responses, endothelial dysfunction, and coagulatory disorders. Based on these mechanisms, we addressed CMD pathophysiology within the context of COVID-19, from five perspectives. The first was the disarrangement of local RAAS and Kallikrein-kinin-systems attributable to SARS-Cov-2 entry, and the concomitant decrease in coronary microvascular endothelial angiotensin I converting enzyme 2 (ACE2) levels. The second was related to coronary microvascular obstruction, induced by COVID-19-associated systemic hyper-inflammation and pro-thrombotic state. The third was focused on how pneumonia/acute respiratory distress syndrome (ARDS)-related systemic hypoxia elicited oxidative stress in coronary microvessels and cardiac sympathetic nerve activation. Fourthly, we discussed how autonomic nerve dysfunction mediated by COVID-19-associated mental, physical, or physiological factors could elicit changes in coronary blood flow, resulting in CMD in COVID-19 patients. Finally, we analyzed reciprocity between the coronary microvascular endothelium and perivascular cellular structures due to viremia, SARS-CoV-2 dissemination, and systemic inflammation. These mechanisms may function either consecutively or intermittently, finally culminating in CMD-mediated cardiovascular symptoms in COVID-19 patients. However, the underlying molecular pathogenesis remains to be clarified.

An overview of sex hormones in relation to SARS-CoV-2 infection

Aim: Sex differences in COVID-19 outcomes might be explained from a sex hormones (SexHs) perspective. Materials & methods: PubMed, Scopus, Web of Science, EMBASE and Google Scholar were searched up to March 2021. Results: Based on the literature review, the crosstalk between SexHs (estrogens, progesterone and testosterone), their receptors (estrogen α and β, androgen, and progesterone) and the immune system shaped the sex-related differences in immune responses against COVID-19. Differential production of SexHs over the lifespan (during pregnancy, reproductive years, menopause and andropause) and over different seasons may result in disparities in body response toward COVID-19. Moreover, SexHs-specific differences might affect vaccine efficacy and response to treatment. Conclusion: The roles of SexHs need to be considered in vaccine development and even treatment of COVID-19.

The effect of estrogen in coronavirus disease 2019

The outcomes of coronavirus disease 2019 (COVID-19) vary between men and women. Some statistical reports have shown that men have a higher risk of developing COVID-19 and suffer from worse outcomes than females. Although there are many factors that can explain the high prevalence of COVID-19 in men, such as lifestyle habits and the different profile of comorbidities among sexes, the distinctions between male and female immune systems cannot be ignored. It has been sufficiently shown that sex differences have a critical influence on the shaping of immune response, which then leads to different pathogenesis in infectious diseases. Compared with males, females typically have a more effective innate and adaptive immune response to viral infections in COVID-19. What's more, there is a growing body of evidence showing that estrogen exerts an effect on the regulation of immune response. This article examines the effect and mechanism of estrogen on COVID-19.

Estrogen Receptor Modulators in Viral Infections Such as SARS-CoV-2: Therapeutic Consequences

COVID-19 is a pandemic respiratory disease caused by the SARS-CoV-2 coronavirus. The worldwide epidemiologic data showed higher mortality in males compared to females, suggesting a hypothesis about the protective effect of estrogens against severe disease progression with the ultimate end being patient's death. This article summarizes the current knowledge regarding the potential effect of estrogens and other modulators of estrogen receptors on COVID-19. While estrogen receptor activation shows complex effects on the patient's organism, such as an influence on the cardiovascular/pulmonary/immune system which includes lower production of cytokines responsible for the cytokine storm, the receptor-independent effects directly inhibits viral replication. Furthermore, it inhibits the interaction of IL-6 with its receptor complex. Interestingly, in addition to natural hormones, phytestrogens and even synthetic molecules are able to interact with the estrogen receptor and exhibit some anti-COVID-19 activity. From this point of view, estrogen receptor modulators have the potential to be included in the anti-COVID-19 therapeutic arsenal.

The role of sexual dimorphism in susceptibility to SARS-CoV-2 infection, disease severity, and mortality: facts, controversies and future perspectives

Former studies have revealed intersex variability in immune response to infectious diseases, including Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological surveillance of the ongoing pandemic has demonstrated a male vulnerability to morbidity and mortality, despite similar infection rates between the two sexes. Divergence in the frequency of comorbidities between males and females, differences in hormonal profile, chromosomal composition and gender behavior have all been proposed as potential causative factors. Data deriving from the immunization process indirectly support the existence of a sex-specific response to SARS-CoV-2, since females apparently produce higher numbers of antibodies while simultaneously exhibiting higher rates of side effects, indicating a stronger immune reactivity to the vaccine's elements. Interpreting intersex differences in immune response to SARS-CoV-2 could lead to a deeper understanding of the COVID-19 pathophysiology and enable healthcare professionals to conduct a more accurate patient risk assessment and better predict the clinical outcome of the disease. This narrative review aims to discuss the pathophysiological and behavioral basis of the disproportionate male morbidity and mortality observed in COVID-19, in the context of most research findings in the field.

COVID-19 pandemic: what about the gonads?

The novel SARS-CoV-2 has spread to virtually all countries of the world infecting millions of people, the medical burden of this disease obviously being enormous. The gonads of both sexes are among the organs that may be affected by COVID-19 and/or may affect the severity of the disease. The clinical spectrum of SARS-CoV-2 infection clearly differs between genders. The current evidence indicates that the underlying mechanism of such an interaction could be associated with genetic, hormonal, and immunological differences, as well as with gender differences in such habits as smoking and alcohol use. On the other hand, there are controversies as to how and to what extent the gonads could be affected by COVID-19, possibly impacting upon sex steroids, fertility, and other functions. This review underlines the possible mechanisms that could clarify these questions concerning COVID-19 and the gonads. In addition, reference is made to potential new treatment modalities presently under investigation, these supported by accumulating data published in the recent literature.

Global Sex Disparity of COVID-19: A Descriptive Review of Sex Hormones and Consideration for the Potential Therapeutic Use of Hormone Replacement Therapy in Older Adults

The 2019-2020 SARS-related coronavirus-2 (SARS-CoV-2) pandemic has brought unprecedented challenges to healthcare sectors around the world. As of November 2020, there have been over 64 million confirmed cases and approaching 2 million deaths globally. Despite the large number of positive cases, there are very limited established standards of care and therapeutic options available. To date, there is still no Food and Drug Administration (FDA) approved vaccine for COVID-19, although there are several options in various clinical trial stages. Herein, we have performed a global review evaluating the roles of age and sex on COVID-19 hospitalizations, ICU admissions, deaths in hospitals, and deaths in nursing homes. We have identified a trend in which elderly and male patients are significantly affected by adverse outcomes. There is evidence suggesting that sex hormone levels can influence immune system function against SARS-CoV-2 infection, thus reducing the adverse effects of COVID-19. Since older adults have lower levels of these sex hormones, we therefore speculate, within rational scientific context, that sex steroids, such as estrogen and progesterone, needs further consideration for use as alternative therapeutic option for treating COVID-19 elderly patients. To our knowledge, this is the first comprehensive article evaluating the significance of sex hormones in COVID-19 outcomes in older adults.

The Looming Effects of Estrogen in Covid-19: A Rocky Rollout

In the face of the Covid-19 pandemic, an intensive number of studies have been performed to understand in a deeper way the mechanisms behind better or worse clinical outcomes. Epidemiologically, men subjects are more prone to severe acute respiratory syndrome-coronavirus type 2 (SARS-CoV-2) infections than women, with a similar scenario being also stated to the previous coronavirus diseases, namely, SARS-CoV in 2003 and Middle East Respiratory Syndrome coronavirus diseases (MERS-CoV) in 2012. In addition, and despite that aging is regarded as an independent risk factor for the severe form of the disease, even so, women protection is evident. In this way, it has been expected that sex hormones are the main determinant factors in gender differences, with the immunomodulatory effects of estrogen in different viral infections, chiefly in Covid-19, attracting more attention as it might explain the case-fatality rate and predisposition of men for Covid-19 severity. Here, we aim to provide a mini-review and an overview on the protective effects of estrogen in Covid-19. Different search strategies were performed including Scopus, Web of Science, Medline, Pubmed, and Google Scholar database to find relative studies. Findings of the present study illustrated that women have a powerful immunomodulating effect against Covid-19 through the effect of estrogen. This study illustrates that estrogens have noteworthy anti-inflammatory and immuno-modulatory effects in Covid-19. Also, estrogen hormone reduces SARS-CoV-2 infectivity through modulation of pro-inflammatory signaling pathways. This study highlighted the potential protective effect of estrogen against Covid-19 and recommended for future clinical trial and prospective studies to elucidate and confirm this protective effect.

Insights into the possible impact of COVID-19 on the endocrine system

The novel 2019 coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly transmissible and pathogenic coronavirus. Because of the novelty of the COVID-19 pandemic, few data are available on the impact of the SARS-CoV-2 on the different endocrine glands. Previous studies of severe acute respiratory syndrome (SARS) have shown a harmful effect on endocrine function. Notably, the angiotensin-converting enzyme-2 receptor, which is the entry route of coronaviruses to the host cell, is widely expressed in the endocrine organs including testis, endocrine pancreas, thyroid, and adrenal, and pituitary glands. Clinical and biochemical manifestations have been recorded in COVID-19 patients resulting in changes in endocrine activities, which were also recorded during the SARS outbreak in 2003. This review aims to explore the impact of SARS-CoV-2 infection on the function of endocrine glands, based on the latest research in the field.

Sex-based differences in severity and mortality in COVID-19

The current coronavirus disease (COVID‐19) pandemic caused by novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has a male bias in severity and mortality. This is consistent with previous coronavirus pandemics such as SARS‐CoV and MERS‐CoV, and viral infections in general. Here, we discuss the sex‐disaggregated epidemiological data for COVID‐19 and highlight underlying differences that may explain the sexual dimorphism to help inform risk stratification strategies and therapeutic options.

Combined hormonal contraception and COVID-19

Aim: This article reviews the possibility of using combined hormonal contraception during the COVID-19 pandemic. Methods: narrative reviewResults: The factors that protect women from the severity of the disease are analysed, as well as the risk factors for the use of this type of contraception, especially related to the increased risk of a thrombotic event in patients affected by the disease. Finally, the information available on the guidelines for action in patients with COVID-19 using combined hormonal contraception is collected.Conclusions: We can continue to prescribe and use hormonal methods with EE.

COVID-19 Outcomes in Postmenopausal and Perimenopausal Females: Is Estrogen Hormone Attributing to Gender Differences?

Background

Globally, case fatality rate is more in males compared to females. Some studies have suggested. It is hypothesized that estrogen hormone may decrease susceptibility to severe acute respiratory syndrome coronavirus 2 (SARS CoV-2.).

Objective

The objective of the study was to evaluate the gender differences in SARS CoV-2 outcomes and to analyze if there are any differences in outcomes in premenopausal females compared to postmenopausal females.

Materials and Methods

Patients tested positive for SARS CoV-2 through real-time reverse transcription-polymerase chain reaction by Thermo Fischer Taqpath assay approved by the Indian Council of Medical Research were included in the study. The data obtained was analyzed for the epidemiological, clinical, and laboratory characteristics from their medical records.

Results

The mortality rate in females was 12.6%, whereas mortality in males was 19.4%. In between-group analysis, 8.6% (16/185) of females died in premenopausal age group versus 12.8% (27/211) in postmenopausal group. The proportion of females who expired due to COVID significantly differ by age and postmenopausal status X2 (1, n = 293) = 7.2, the P value is 0.007. The difference is statistically significant at P < 0.05. Postmenopausal women were more likely to expire due to COVID-19 infection compared to premenopausal women.

Conclusion

The mortality rate in postmenopausal age group was greater than mortality in premenopausal females emphasizing the protection provided by estrogens hormone in them. Postmenopausal women are also at higher risk of severe COVID-19 infection than premenopausal women. Mortality is greater in males compared to females, further strengthening the role of estrogens.

Sex bias of females in survival from cancer and infections. Is X the answer?

Major differences in survival of men and women from infectious diseases and cancers have been highlighted by death rates from COVID-19 infections. In cancer, attention has been focussed on differences in gene expression from X chromosomes in men and women with a preponderance of genes involved in immune responses being expressed in women. Important findings have been that some of the genes are important epigenetic regulators that play fundamental roles in immune responses.

Change in Covid-19 infection and mortality rates in postmenopausal women

OBJECTIVE

To evaluate whether the rates of COVID-19 infection and death in women versus men differ with age.

METHODS

From data provided by the Italian National Institute of Statistics, we calculated the respective proportions of women among COVID-infected versus noninfected populations and male versus female infection and death rates, stratifying the results into 10-year age groups.

RESULTS

The prevalence of COVID-19 infection was 3.6% higher in women than in the general population from 20 to 59 years of age, then decreased to -13.3% below that of the general population between 60 and 89 years of age. Death rates among infected women showed the opposite age-related trend. In infected women, the mortality rate was -77.4% lower than that of men aged 20 to 59 years. Between 60 and 89 years of age, the difference in women decreases to -34.5% below that of men.

CONCLUSIONS

Our results indicate opposing age-related trends among women in infection and death rates due to COVID-19. Further studies are needed to examine the contribution of the phases of the female reproductive cycle to the observed variations.

Evidence for treatment with estradiol for women with SARS-CoV-2 infection

BACKGROUND

Given that an individual's age and gender are strongly predictive of coronavirus disease 2019 (COVID-19) outcomes, do such factors imply anything about preferable therapeutic options?

METHODS

An analysis of electronic health records for a large (68,466-case), international COVID-19 cohort, in 5-year age strata, revealed age-dependent sex differences. In particular, we surveyed the effects of systemic hormone administration in women. The primary outcome for estradiol therapy was death. Odds ratios (ORs) and Kaplan-Meier survival curves were analyzed for 37,086 COVID-19 women in two age groups: pre- (15-49 years) and peri-/post-menopausal (> 50 years).

RESULTS

The incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is higher in women than men (by about + 15%) and, in contrast, the fatality rate is higher in men (about + 50%). Interestingly, the relationships between these quantities are linked to age: pre-adolescent girls and boys had the same risk of infection and fatality rate, while adult premenopausal women had a significantly higher risk of infection than men in the same 5-year age stratum (about 16,000 vs. 12,000 cases). This ratio changed again in peri- and postmenopausal women, with infection susceptibility converging with men. While fatality rates increased continuously with age for both sexes, at 50 years, there was a steeper increase for men. Thus far, these types of intricacies have been largely neglected. Because the hormone 17ß-estradiol influences expression of the human angiotensin-converting enzyme 2 (ACE2) protein, which plays a role in SARS-CoV-2 cellular entry, propensity score matching was performed for the women's sub-cohort, comparing users vs. non-users of estradiol. This retrospective study of hormone therapy in female COVID-19 patients shows that the fatality risk for women > 50 years receiving estradiol therapy (user group) is reduced by more than 50%; the OR was 0.33, 95% CI [0.18, 0.62] and the hazard ratio (HR) was 0.29, 95% CI [0.11,0.76]. For younger, pre-menopausal women (15-49 years), the risk of COVID-19 fatality is the same irrespective of estradiol treatment, probably because of higher endogenous estradiol levels.

CONCLUSIONS

As of this writing, still no effective drug treatment is available for COVID-19; since estradiol shows such a strong improvement regarding fatality in COVID-19, we suggest prospective studies on the potentially more broadly protective roles of this naturally occurring hormone.

Multi-omics-based identification of SARS-CoV-2 infection biology and candidate drugs against COVID-19

SARS-CoV-2 has ushered a global pandemic with no effective drug being available at present. Although several FDA-approved drugs are currently under clinical trials for drug repositioning, there is an on-going global effort for new drug identification. In this paper, using multi-omics (interactome, proteome, transcriptome, and bibliome) data and subsequent integrated analysis, we present the biological events associated with SARS-CoV-2 infection and identify several candidate drugs against this viral disease. We found that: (i) Interactome-based infection pathways differ from the other three omics-based profiles. (ii) Viral process, mRNA splicing, cytokine and interferon signaling, and ubiquitin mediated proteolysis are important pathways in SARS-CoV-2 infection. (iii) SARS-CoV-2 infection also shares pathways with Influenza A, Epstein-Barr virus, HTLV-I, Measles, and Hepatitis virus. (iv) Further, bacterial, parasitic, and protozoan infection pathways such as Tuberculosis, Malaria, and Leishmaniasis are also shared by this virus. (v) A total of 50 candidate drugs, including the prophylaxis agents and pathway specific inhibitors are identified against COVID-19. (vi) Betamethasone, Estrogen, Simvastatin, Hydrocortisone, Tositumomab, Cyclosporin A etc. are among the important drugs. (vii) Ozone, Nitric oxide, plasma components, and photosensitizer drugs are also identified as possible therapeutic candidates. (viii) Curcumin, Retinoic acids, Vitamin D, Arsenic, Copper, and Zinc may be the candidate prophylaxis agents. Nearly 70% of our identified agents are previously suggested to have anti-COVID-19 effects or under clinical trials. Among our identified drugs, the ones that are not yet tested, need validation with caution while an appropriate drug combination from these candidate drugs along with a SARS-CoV-2 specific antiviral agent is needed for effective COVID-19 management.