Viral threat to male fertility

Clinical and Laboratorial Evaluation of Male Infertility. A Detailed Practical Approach

Infertility, defined as the inability to achieve pregnancy after one year of unprotected, frequent sexual intercourse, is a global burden that affects approximately 15% of couples, or 190-230 million people worldwide, who are trying to start a family. The male contributes significantly, directly accounting for 30-35% and up to 52% of total couple infertility, affecting approximately 7-8% of all men. This work aims to present, in a didactic and objective way, a standardization of the initial steps toward a thorough evaluation of subfertile and infertile men. We have focused on the evaluation of initial management, emphasizing the need for a comprehensive evaluation that includes a detailed history, physical examination, and semen analysis as the golden triple helix of basic evaluation of the infertile male. General and genital physical examinations are highly valuable due to the wealth of information they provide, from potential diagnoses to pregnancy prognoses. Comprehensive and quality-controlled semen analysis provides reliable information as a baseline test to evaluate the patency of the reproductive tract and to evaluate basic sperm parameters and fertility potential. However, it is not a fertility determinant and should preferentially be complemented with sperm functional tests. like biomarkers of oxidative stress, sperm immaturity and DNA fragmentation. Most cases of infertility require evaluation by a specialist in andrology, nonetheless the understanding and rationale of the initial assessment of the infertile male can be undertaken by non-specialists, thus improving the care and counseling of couples facing this troubling issue and avoiding unnecessary use of assisted reproductive technologies (ART) since most cases of male infertility can be treated and reversed by medical or surgical interventions, and the fertility status can be restored. The ultimate goal is to achieve natural pregnancy, the use of ART should not be the initial offered resource.

Association between post-COVID-19 conditions and male semen quality in Japan: A descriptive investigation

Some reports suggest that coronavirus disease 2019 (COVID-19) may affect male reproductive function. There is also concern in Japan that COVID-19 may contribute to the pre-existing decline in male fertility; however, no studies have investigated the effects of COVID-19 on male reproductive function. In this study, we aimed to analyze the semen quality of men who had recovered from COVID-19. Male patients who had recovered from COVID-19 between February 2020 and September 2021 were recruited for this study. Participants were sent a semen collection kit; they were asked to collect semen at home and deliver it to a laboratory at Osaka University. We used these samples to analyze sperm concentration, total sperm count, and semen volume. In total, 125 participants were included in this study. The median age of all patients was 46 years (interquartile range (IQR): 38-52 years). The severity of COVID-19 was mild in 80 patients; 19 were moderate I, 22 were moderate II, and four were severe. The median semen volume was 2.5 mL (IQR: 1.8-3.1), the median sperm concentration was 98.9 million/mL (IQR: 43.8-162.2), and the median total sperm count was 212.1 million (IQR: 89.7-368.2). In a previous study in Japan, the median sperm count in adult men was reported to be 201 million. Participants in our study did not have lower sperm counts than this, despite their older age. Our results suggest that the long-term effects of COVID-19 on spermatogenesis are minimal.

Investigating the effects of the Omicron variant of COVID-19 on sperm parameters and serum levels of male sexual hormones: Prospective observational study

Background

With the progress and prevalence of COVID-19, concerns have arisen regarding its impact on men's sexual health. Therefore, this study was conducted with the aim of examining the effects of COVID-19 on serum levels of sex hormones and semen.

Methods

Sixty participants who met the study inclusion criteria enrolled in this study between January and April 2022. The individuals were divided into three groups (n = 20): healthy, COVID-19 positive, and recovered from COVID-19. Blood and semen samples were collected from the participants. Serum levels of sex hormones and semen were evaluated both macroscopically and microscopically.

Results

Our study results showed that the most common symptoms observed in the COVID-19 group were cough (100 %), fever (100 %), fatigue (95 %), and runny nose (90 %). Serum levels of sex hormones (testosterone, FSH, and prolactin) in the COVID-19 group were significantly decreased compared to the healthy group. Microscopic examination of semen revealed significant differences in vitality, progressive, and motile parameters among the three groups, with a decrease observed in the COVID-19 group.

Conclusion

These results indicate that COVID-19 may have a negative impact on men's sexual health, potentially affecting hormone production and sperm quality. Further research is needed to determine the long-term effects of COVID-19 on male fertility and to explore potential treatment options.

Cytotoxic and viricidal effects of human semen on mumps virus-infected lymphocytes: In vitro studies

Viruses in human semen may be sexually transmitted via free and cell-mediated viral infection. The potential effects of semen on the infection and sexual transmission of most viruses in semen remain largely unclear. The present study elucidated the inhibitory effects of human seminal plasma (SP) on Jurkat cell (JC)-mediated mumps virus (MuV) infection. We demonstrated that MuV efficiently infected JCs and that the JCs infected by MuV (JC-MuV) mediated MuV infection of HeLa cells. Remarkably, SP was highly cytotoxic to JCs and inhibited JC-MuV infection of HeLa cells. The cytotoxic factor possessed a molecular weight of less than 3 kDa, whereas that of the viricidal factor was over 100 kDa. The cooperation of cytotoxic and viricidal factors was required for the SP inhibition of JC-MuV infection, and prostatic fluid (PF) was responsible for both the cytotoxic and viricidal effects of SP. The cytotoxic effects we observed were resistant to the treatment of PF with boiling water, proteinase K, RNase A, and DNase I. Our results provide novel insights into the antiviral properties of SP, which may limit cell-mediated sexual viral transmission.

Systematic analyses of the factors influencing sperm quality in patients with SARS-CoV-2 infection

To figure out how does SARS-CoV-2 affect sperm parameters and what influencing factors affect the recovery of sperm quality after infection? We conducted a prospective cohort study and initially included 122 men with SARS-CoV-2 infection. The longest time to track semen quality after infection is 112 days and 58 eligible patients were included in our study eventually. We subsequently exploited a linear mixed-effects model to statistically analyze their semen parameters at different time points before and after SARS-CoV-2 infection. Semen parameters were significantly reduced after SARS-CoV-2 infection, including total sperm count (211 [147; 347] to 167 [65.0; 258], P < 0.001), sperm concentration (69.0 [38.8; 97.0] to 51.0 [25.5; 71.5], P < 0.001), total sperm motility (57.5 [52.3; 65.0] to 51.0 [38.5; 56.8], P < 0.001), progressive motility (50.0 [46.2; 58.0] to 45.0 [31.5; 52.8], P < 0.001). The parameters displayed the greatest diminution within 30 days after SARS-CoV-2 infection, gradually recovered thereafter, and exhibited no significant difference after 90 days compared with prior to COVID-19 infection. In addition, the patients in the group with a low-grade fever showed a declining tendency in semen parameters, but not to a significant degree, whereas those men with a moderate or high fever produced a significant drop in the same parameters. Semen parameters were significantly reduced after SARS-CoV-2 infection, and fever severity during SARS-CoV-2 infection may constitute the main influencing factor in reducing semen parameters in patients after recovery, but the effect is reversible and the semen parameters gradually return to normal with the realization of a new spermatogenic cycle.

Update on known and emergent viruses affecting human male genital tract and fertility

Many viruses infect the male genital tract with harmful consequences at individual and population levels. In fact, viral infections may induce damage to different organs of the male genital tract (MGT), therefore compromising male fertility. The oxidative stress, induced during viral-mediated local and systemic inflammation, is responsible for testicular damage, compromising germinal and endocrine cell functions. A reduction in sperm count, motility, number of normal sperm and an increase in DNA fragmentation are all common findings in the course of viral infections that, however, generally regress after infection clearance. In some cases, however, viral shedding persists for a long time leading to unexpected sexual transmission, even after the disappearance of the viral load from the blood.The recent outbreak of Zika and Ebola Virus evidenced how the MGT could represent a reservoir of dangerous emergent viruses and how new modalities of surveillance of survivors are strongly needed to limit viral transmission among the general population.Here we reviewed the evidence concerning the presence of relevant viruses, including emergent and re-emergent, on the male genital tract, their route of entry, their adverse effects on male fertility and the pattern of viral shedding in the semen.We also described laboratory strategies to reduce the risk of horizontal or vertical cross-infection in serodiscordant couples undergoing assisted reproductive technologies.

Radiological Evidence of Testicular Damage in Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Sonoelastography's Potential Role

ABSTRACT

This preliminary study aimed to evaluate the possible damage to the male reproductive system that the severe acute respiratory syndrome coronavirus 2 virus causes by quantitatively measuring and comparing the tissue stiffness of the testis and epididymis with acoustic radiation force impulse sonoelastography in patients who have COVID-19 with a healthy control group. This prospective study was conducted between February and July 2021 with 65 cases. We used sonoelastography to evaluate male patients 18 years or older, who had applied to the urology clinic with nontesticular complaints, and were found to not have any underlying testicular pathology after a clinical-laboratory evaluation. The clinical-laboratory imaging findings and reverse transcription-polymerase chain reaction test results of all patients diagnosed with COVID-19 were reviewed from the hospital database. We measured the shear wave velocity values of the epididymis and the testes of 31 proven severe acute respiratory syndrome coronavirus 2 patients and 34 healthy subjects and compared them with an independent t test. For the patient and control group subjects, the mean age was 37.55 ± 13.08 (23-71) and 40.5 ± 16.25 (18-81) years, respectively. The mean shear wave velocity values of the left-right and bilateral testes and epididymis of the patient group were statistically substantially higher ( P ˂ 0.05) than in the control group. In the receiver operating characteristic analysis, when the cutoff values for the bilateral testes and epididymis were determined as 1.39 and 1.64 m/s, respectively, the AUC was 77% to 73.4%, the sensitivity was 87% to 74%, and the specificity was 65% to 62%. Our findings show that testicular and epididymal tissue stiffness increased in patients with COVID-19. We recommend adding sonoelastography to urogenital examinations of male reproductive system in patients who are recovering from COVID-19.

Study on the cytokines related to SARS-Cov-2 in testicular cells and the interaction network between cells based on scRNA-seq data

Inflammatory cytokine storms (CS) in COVID-19 patients are associated with elevated levels of 13 specific cytokines, potentially impacting male fertility by causing testicular cell damage and disrupting the immune microenvironment. Some patients present with scrotal discomfort and orchitis. However, few studies have explored cytokine expression in testicular cells and their role in cell-to-cell communication. In this study, we integrated single-cell sequencing data sets of testicular cells, annotating 20 cell clusters using marker genes and the Human Cell Landscape database. We constructed cell pseudo-chronological trajectories, hub genes, and analyzed the cytokine interaction network between sperm cells using CellChat. Our findings identified 12 types of testicular cells, with four cytokines (IL8, CCL2, CCL3, and TNF) potentially involved in immune processes. Pseudo-chronological trajectory analysis indicated IL8 and CCL3's essential roles in testicular macrophages and endothelial cell development, affecting the immune microenvironment. We determined eight key cytokines (IL1, IL2, IL4, IL6, CCL, CSF3, TNF, and IFN-II) functions in cell interaction networks. Network analysis of exogenous cytokines directly acting on testicular cells showed IL2 potentially affecting all testicular cells, suggesting a vital role in cell communication. This research offers valuable insights into CSs effects on testicular cells and their potential impact on male fertility during COVID-19 infection.

Research progress on the role and mechanism of DNA damage repair in germ cell development

In the complex and dynamic processes of replication, transcription, and translation of DNA molecules, a large number of replication errors or damage can occur which lead to obstacles in the development process of germ cells and result in a decreased reproductive rate. DNA damage repair has attracted widespread attention due to its important role in the maintenance and regulation of germ cells. This study reports on a systematic review of the role and mechanism of DNA damage repair in germline development. First, the causes, detection methods, and repair methods of DNA damage, and the mechanism of DNA damage repair are summarized. Second, a summary of the causes of abnormal DNA damage repair in germ cells is introduced along with common examples, and the relevant effects of germ cell damage. Third, we introduce the application of drugs related to DNA damage repair in the treatment of reproductive diseases and related surgical treatment of abnormal DNA damage, and summarize various applications of DNA damage repair in germ cells. Finally, a summary and discussion is given of the current deficiencies in DNA damage repair during germ cell development and future research development. The purpose of this paper is to provide researchers engaged in relevant fields with a further systematic understanding of the relevant applications of DNA damage repair in germ cells and to gain inspiration from it to provide new research ideas for related fields.

Deciphering the Molecular Characteristics of Human Idiopathic Nonobstructive Azoospermia from the Perspective of Germ Cells

Nonobstructive azoospermia (NOA) is one of the most important causes of male infertility, accounting for 10-15% of infertile men worldwide. Among these, more than 70% of cases are idiopathic NOA (iNOA), whose pathogenesis and molecular basis remain unknown. This work profiles 3696 human testicular single-cell transcriptomes from 17 iNOA patients, which are classified into four classes with different arrest periods and variable cell proportions based on the gene expression patterns and pathological features. Genes related to the cell cycle, energy production, and gamete generation show obvious abnormalities in iNOA germ cells. This work identifies several candidate causal genes for iNOA, including CD164, LELP1, and TEX38, which are significantly downregulated in iNOA germ cells. Notably, CD164 knockdown promotes apoptosis in spermatogonia. Cellular communications between spermatogonial stem cells and Sertoli cells are disturbed in iNOA patients. Moreover, BOD1L2, C1orf194, and KRTCAP2 are found to indicate testicular spermatogenic capacity in a variety of testicular diseases, such as Y-chromosome microdeletions and Klinefelter syndrome. In general, this study analyzes the pathogenesis of iNOA from the perspective of germ cell development, transcription factor (TF) regulatory networks, as well as germ cell and somatic cell interactions, which provides new ideas for clinical diagnosis.

Evaluation and management of male genital tract infections in the setting of male infertility: an updated review

PURPOSE OF REVIEW

Male infertility may be secondary to male genital tract infection (MGTI) in an estimated 15% of cases. In the absence of overt clinical signs, evaluation for MGTI beyond semen analysis is not well established. Therefore, we review the literature on the evaluation and management of MGTI in the setting of male infertility.

RECENT FINDINGS

A set of international guidelines recommends semen culture and PCR testing, but the significance of positive results remains unclear. Clinical trials evaluating anti-inflammatory or antibiotic treatment report improvements in sperm parameters and leukocytospermia, but data on the effect on conception rates are lacking. Human papillomavirus (HPV) and the novel coronavirus (SARS-CoV-2) have been associated with poor semen parameters and decreased conception rates.

SUMMARY

The finding of leukocytospermia on semen analysis prompts further evaluation for MGTI, including focused physical examination. The role of routine semen culture is controversial. Treatment options include anti-inflammatories; frequent ejaculation; and antibiotics, which should not be used in the absence of symptoms or microbiological infection. SARS-CoV-2 represents a subacute threat to fertility that should be screened for in the reproductive history along with HPV and other viruses.

Single-cell RNA sequencing reveals the fragility of male spermatogenic cells to Zika virus-induced complement activation

Zika virus (ZIKV) is a potential threat to male reproductive health but the mechanisms underlying its influence on testes during ZIKV infection remain obscure. To address this question, we perform single-cell RNA sequencing using testes from ZIKV-infected mice. The results reveal the fragility of spermatogenic cells, especially spermatogonia, to ZIKV infection and show that the genes of the complement system are significantly upregulated mainly in infiltrated S100A4 + monocytes/macrophages. Complement activation and its contribution to testicular damage are validated by ELISA, RT‒qPCR and IFA and further verify in ZIKV-infected northern pigtailed macaques by RNA genome sequencing and IFA, suggesting that this might be the common response to ZIKV infection in primates. On this basis, we test the complement inhibitor C1INH and S100A4 inhibitors sulindac and niclosamide for their effects on testis protection. C1INH alleviates the pathological change in the testis but deteriorates ZIKV infection in general. In contrast, niclosamide effectively reduces S100A4 + monocyte/macrophage infiltration, inhibits complement activation, alleviates testicular damage, and rescues the fertility of male mice from ZIKV infection. This discovery therefore encourages male reproductive health protection during the next ZIKV epidemic.

Effect of COVID-19 on sperm parameters: pathologic alterations and underlying mechanisms

The rapid outbreak of the coronavirus disease 2019 (COVID-19) pandemic has brought challenges to different medical fields, especially reproductive health. To date, most studies on the effects of COVID-19 on male reproduction have some limitations. In addition, there is little research on the mechanisms underlying by which severe acute respiratory syndrome coronavirus 2 infection affects semen quality. Here, we revealed the possible impact of COVID-19 on sperm parameters and the potential mechanisms. At present, it is still controversial whether COVID-19-induced fever adversely affects sperm parameters. Severe acute respiratory syndrome coronavirus 2 can induce up-regulation of pro-inflammatory cytokine, which leads to the destruction of blood-testis barrier and impairment of spermatogenesis. Moreover, severe viral infection of the respiratory system could induce systemic oxidative stress. Sperm are highly vulnerable to it due to their limited levels of antioxidant defense, unsophisticated DNA damage detection and repair mechanisms. Our review prompt medical staff and patients to consciously check the reproductive function of COVID-19 male patients. Moreover, opening our prospective beyond the direct infection could be the key to better understand the COVID-19 short and long-term effects and provide a new idea for future treatment of patients with reproductive function injury.

A tissue specific-infection mouse model of SARS-CoV-2

Animal models play crucial roles in the rapid development of vaccines/drugs for the prevention and therapy of COVID-19, but current models have some deficits when studying the pathogenesis of SARS-CoV-2 on some special tissues or organs. Here, we generated a human ACE2 and SARS-CoV-2 N^F/F knockin mouse line that constitutively expresses human ACE2 and specifically expresses SARS-CoV-2 N gene induced by Cre-recombinase. By crossing with Cre transgenic lines allowing for lung-specific and constitutive expression, we generated lung-specific (Sftpc-hACE2-N^F/F) and constitutive SARS-CoV-2 N (EIIa-hACE2-N^F/F) expressing mice. Upon intranasal infection with a SARS-CoV-2 GFP/ΔN strain which can only replicate in SARS-CoV-2 N expressed cells, we demonstrated that both the Sftpc-hACE2-N^F/F and EIIa-hACE2-N^F/F mice support viral replication. Consistent with our design, viral replication was limited to the lung tissues in Sftpc-hACE2-N^F/F mice, while the EIIa-hACE2-N^F/F mice developed infections in multiple tissues. Furthermore, our model supports different SARS-CoV-2 variants infection, and it can be successfully used to evaluate the effects of therapeutic monoclonal antibodies (Ab1F11) and antiviral drugs (Molnupiravir). Finally, to test the effect of SARS-CoV-2 infection on male reproduction, we generated Sertoli cell-specific SARS-CoV-2 N expressed mice by crossing with AMH-Cre transgenic line. We found that SARS-CoV-2 GFP/ΔN strain could infect Sertoli cells, led to spermatogenic defects due to the destruction of blood-testis barrier. Overall, combining with different tissue-specific Cre transgenic lines, the human ACE2 and SARS-CoV-2 N^F/F line enables us to evaluate antivirals in vivo and study the pathogenesis of SARS-CoV-2 on some special tissues or organs.

Zika Virus Infection Damages the Testes in Pubertal Common Squirrel Monkeys (Saimiri collinsi)

During the Zika virus (ZIKV) outbreak and after evidence of its sexual transmission was obtained, concerns arose about the impact of the adverse effects of ZIKV infection on human fertility. In this study, we evaluated the clinical-laboratory aspects and testicular histopathological patterns of pubertal squirrel monkeys (Saimiri collinsi) infected with ZIKV, analyzing the effects at different stages of infection. The susceptibility of S. collinsi to ZIKV infection was confirmed by laboratory tests, which detected viremia (mean 1.63 × 106 RNA copies/µL) and IgM antibody induction. Reduced fecal testosterone levels, severe testicular atrophy and prolonged orchitis were observed throughout the experiment by ultrasound. At 21 dpi, testicular damage associated with ZIKV was confirmed by histopathological and immunohistochemical (IHC) analyses. Tubular retraction, the degeneration and necrosis of somatic and germ cells in the seminiferous tubules, the proliferation of interstitial cells and an inflammatory infiltrate were observed. ZIKV antigen was identified in the same cells where tissue injuries were observed. In conclusion, squirrel monkeys were found to be susceptible to the Asian variant of ZIKV, and this model enabled the identification of multifocal lesions in the seminiferous tubules of the infected group evaluated. These findings may suggest an impact of ZIKV infection on male fertility.

Insights into the Scenario of SARS-CoV-2 Infection in Male Reproductive Toxicity

COVID-19 has become a significant public health concern that has catastrophic consequences for society. Some preliminary evidence suggests that the male reproductive system may be an infection target for SARS-CoV-2. SARS-CoV-2 may be transmitted sexually, according to preliminary research. Testicular cells exhibit a high level of the angiotensin-converting enzyme 2 (ACE2) receptor, which enhances the entry of the SARS-CoV-2 into host cells. Some instances of COVID-19 have been documented to exhibit hypogonadism during the acute stage. Furthermore, systemic inflammatory reactions triggered by SARS-CoV-2 infection may cause oxidative stress (OS), which has been shown to have profoundly deleterious consequences on testicular functioning. This work gives a clear picture of how COVID-19 may affect male reproductive systems and calls attention to the many unanswered questions about the mechanisms by which this virus can be linked to men's health and fertility.

High SARS-CoV-2 tropism and activation of immune cells in the testes of non-vaccinated deceased COVID-19 patients

BACKGROUND

Cellular entry of SARS-CoV-2 has been shown to rely on angiotensin-converting enzyme 2 (ACE2) receptors, whose expression in the testis is among the highest in the body. Additionally, the risk of mortality seems higher among male COVID-19 patients, and though much has been published since the first cases of COVID-19, there remain unanswered questions regarding SARS-CoV-2 impact on testes and potential consequences for reproductive health. We investigated testicular alterations in non-vaccinated deceased COVID-19-patients, the precise location of the virus, its replicative activity, and the immune, vascular, and molecular fluctuations involved in the pathogenesis.

RESULTS

We found that SARS-CoV-2 testicular tropism is higher than previously thought and that reliable viral detection in the testis requires sensitive nanosensors or RT-qPCR using a specific methodology. Through an in vitro experiment exposing VERO cells to testicular macerates, we observed viral content in all samples, and the subgenomic RNA's presence reinforced the replicative activity of SARS-CoV-2 in testes of the severe COVID-19 patients. The cellular structures and viral particles, observed by transmission electron microscopy, indicated that macrophages and spermatogonial cells are the main SARS-CoV-2 lodging sites, where new virions form inside the endoplasmic reticulum Golgi intermediate complex. Moreover, we showed infiltrative infected monocytes migrating into the testicular parenchyma. SARS-CoV-2 maintains its replicative and infective abilities long after the patient's infection. Further, we demonstrated high levels of angiotensin II and activated immune cells in the testes of deceased patients. The infected testes show thickening of the tunica propria, germ cell apoptosis, Sertoli cell barrier loss, evident hemorrhage, angiogenesis, Leydig cell inhibition, inflammation, and fibrosis.

CONCLUSIONS

Our findings indicate that high angiotensin II levels and activation of mast cells and macrophages may be critical for testicular pathogenesis. Importantly, our findings suggest that patients who become critically ill may exhibit severe alterations and harbor the active virus in the testes.

Mice 3D testicular organoid system as a novel tool to study Zika virus pathogenesis

Zika virus (ZIKV) poses a serious threat to global public health due to its close relationship with neurological and male reproductive damage. However, deficiency of human testicular samples hinders the in-depth research on ZIKV-induced male reproductive system injury. Organoids are relatively simple in vitro models, which could mimic the pathological changes of corresponding organs. In this study, we constructed a 3D testicular organoid model using primary testicular cells from adult BALB/c mice. Similar to the testis, this organoid system has a blood-testis barrier (BTB)-like structure and could synthesize testosterone. ZIKV tropism of testicular cells and ZIKV-induced pathological changes in testicular organoid was also similar to that in mammalian testis. Therefore, our results provide a simple and reproducible in vitro testicular model for the investigations of ZIKV-induced testicular injury.

An Assessment of Men Semen Alterations in SARS-CoV-2: Is Fever the Principal Concern?

The SARS-CoV-2 virus (COVID-19) was identified as a pandemic in March 2020 by the World Health Organization. The virus spreads primarily through saliva droplets or nasal discharges, in addition to coughing or sneezing from an infected person. The most common symptom at the onset of illness is fever, which may appear within 2-14 days after exposure. The high fever (above 38 °C) can persist from one to 4 days. The febrile illness usually has a variable negative impact on sperm characteristics such as sperm output, motility, morphology, and DNA fragmentation. These defects proliferated due to an increase in testicular temperature, and disturbance in the thermoregulatory systems that are responsible for the testicular heat loss. Coronavirus studies suggest that fever from SARS-CoV-2 virus infection induces a reversible negative effect on the sperm parameters until one cycle (74 days) of spermatogenesis. We believe that SARS-CoV-2 can have long-term adverse effects on testicles via immune or inflammatory reactions after the patient has fully recovered. This evidence could be added to the list of the long-term post-COVID-19 syndromes. Long-term follow-up and evaluation of the sperm parameters are necessary for all recovered male patients, especially the young ones.

Human seminal virome: a panel based on recent literature

Background

The seminal virome and its implications for fertility remain poorly understood. To date, there are no defined panels for the detection of viruses of clinical interest in seminal samples.

Results

In this study, we characterized the human seminal virome based on more than 1,000 studies published over the last five years.

Conclusions

The number of studies investigating viruses that occur in human semen has increased, and to date, these studies have been mostly prospective or related to specific clinical findings. Through the joint analysis of all these studies, we have listed the viruses related to the worsening of seminal parameters and propose a new panel with the main viruses already described that possibly affect male fertility and health. This panel can assist in evaluating semen quality and serve as a tool for investigation in cases of infertility.

Risk factors on testicular function in adolescents

PURPOSE

Adolescence represents an important window for gonadal development. The aim of this review is to carry out a critical excursus of the most recent literature on endogenous and exogenous risk factors related to testicular function, focusing the research on adolescence period.

METHODS

A comprehensive literature search within PubMed was performed to provide a summary of currently available evidence regarding the impact on adolescence of varicocele, cryptorchidism, cancer, diabetes, lifestyle factors, endocrine disruptors, obesity and sexually transmitted diseases. We focused on human studies that evaluated a possible impact of these factors on puberty timing and their effects on andrological health.

RESULTS

Evidence collected seems to suggest that andrological health in adolescence may be impaired by several factors, as varicocele, cryptorchidism, and childhood cancer. Despite an early diagnosis and treatment, many adolescents might still have symptoms and sign of a testicular dysfunction in their adult life and at the current time it is not possible to predict which of them will experience andrological problems. Lifestyle factors might have a role in these discrepancies. Most studies point out towards a correlation between obesity, insulin resistance, alcohol, smoking, use of illegal drugs and testicular function in pubertal boys. Also, endocrine disruptors and sexually transmitted diseases might contribute to impair reproductive health, but more studies in adolescents are needed.

CONCLUSION

According to currently available evidence, there is an emerging global adverse trend of high-risk and unhealthy behaviors in male adolescents. A significant proportion of young men with unsuspected and undiagnosed andrological disorders engage in behaviors that could impair testicular development and function, with an increased risk for later male infertility and/or hypogonadism during the adult life. Therefore, adolescence should be considered a key time for intervention and prevention of later andrological diseases.

Hepatitis B Virus and Cytomegalovirus Infections Disrupt Sperm Parameters in Males through Decreasing Mitochondrial Membrane Potential: A Case-control Study

Background: Infertility is a global problem that affects more than 15% of couples. The occurrence of this problem is about 50% in males. Viral infections cause infertility in men by different mechanisms. Objectives: This study is designed to evaluate the effects of hepatitis B virus (HBV) and cytomegalovirus (CMV) infection on male fertility and determine the mechanisms involved. Methods: A total of 73 males were included in the present study. They were assigned to the groups healthy fertile (n = 22 volunteers) as the healthy controls, non-infected infertile (n = 27), HBV-infected infertile (n = 14), and CMV-infected infertile (n = 10). The sperm parameters, including count, morphology, progressive motility (PR), and progressive + non-progressive motility (PR + NP), were analyzed in their semen. The semen samples of all studied participants were subjected to polymerase chain reaction to determine the presence of HBV or CMV infection. Mitochondrial membrane potential (MMP) and tumor necrosis factor-alpha (TNF-α) were also assessed. Results: Our findings showed that all sperm parameters, including count, morphology, PR, and PR + NP, decreased in males with HBV and CMV infections compared to the healthy control group (P < 0.01 in all cases). MMP declined in HBV- and CMV-infected males compared to the healthy control group (P < 0.001). Conversely, the TNF-α level of semen in HBV- and CMV-infected men was significantly higher than in the healthy control group (P < 0.001). Conclusions: The results of the present study demonstrated that HBV and CMV infections lead to male infertility through increasing TNF-α and decreasing sperm MMP.

The potential impact of COVID-19 on male reproductive health

The SARS-CoV-2 virus continues to overwhelm health care systems impairing human to human social and economic interactions. Invasion or damage to the male reproductive system is one of the documented outcomes of viral infection. Existing studies have reported that SARS-CoV-2 may contribute to this loss in relation to inflammatory responses and the formation of cytokine storms in COVID-19 patients. Although direct infection of the testes and entry of SARS-CoV-2 into semen as well as subsequent consequences on the male reproductive system need to be studied more systematically, warnings from two organising ASRM and SART for prospective parents when infected with SARS-CoV-2 should be considered. In the context of an increasingly complex pandemic, this review provides preliminary examples of the potential impact of COVID-19 on male reproductive health and guidance for prospective parents currently infected with or recovering from SARS-CoV-2.

SARS-CoV-2 Nucleocapsid Protein is Associated With Lower Testosterone Levels: An Experimental Study

The ongoing COVID-19 pandemic represents an extra burden in the majority of public and private health systems worldwide beyond the most pessimistic expectations, driving an urgent rush to develop effective vaccines and effective medical treatments against the SARS-CoV-2 pandemic. The Nucleocapsid structural viral protein is remarkably immunogenic and hugely expressed during infection. High IgG antibodies against Nucleocapsid protein (N protein) levels were detected in the serum of COVID-19 patients, confirming its pivotal antigen role for a T lymphocyte response in a vaccine microenvironment. Currently, adverse events associated with immunizations have raised some degree of concern, irrespective of its huge benefits in dealing with disease severity and decreasing mortality and morbidity. This hitherto study evaluates histological changes in rats’ testes, epididymis, prostate, and seminal vesicles and analyzes hormone levels after solely N protein inoculation. Therefore, we exposed a group of Lewis rats to weekly injections of the recombinant N protein for 28 days, while a control group was inoculated with a buffer solution. The N group revealed a more significant number of spermatozoa. Spermatozoa in the seminiferous tubules were counted in twenty 400 × microscopy fields (mean of 9.2 vs. 4.6 in the control group; p &lt; 0,01), but significantly lower testosterone levels (mean of 125.70 ng/dl vs. 309,00 ng/dl in the control group; p &lt; 0,05) were found. No other histological and biochemical changes were displayed. Conclusively, these data suggest testicular hormonal imbalance mediated by the SARS-CoV-2 N protein that could be linked to reported post-COVID-19 syndrome hypogonadism. More relevant research might be performed to confirm this viral antigen’s deleterious mechanism in the human testicular microenvironment, particular in Leydig cell function.

Evaluation of the Presence of Bacterial and Viral Agents in the Semen of Infertile Men: A Systematic and Meta-Analysis Review Study

Objectives

Infections in the male genitourinary system with bacterial and viral agents may play a significant role in male infertility. These agents usually infect the urethra, seminal vesicles, prostate, epididymis, vas deferens, and testes retrograde through the reproductive system. A meta-analysis review study was performed to evaluate the presence of bacterial and viral agents in the semen of infertile men and its correlation with infertility.

Methods

Relevant cross-sectional and/or case-control studies were found by an online review of national and international databases (Web of Science, PubMed, Scopus, Science Direct, and Google scholar), and suitable studies were selected. A checklist determined the qualities of all studies. Heterogeneity assay among the primary studies was evaluated by Cochran’s Q test and I² index (significance level 50%). A statistical analysis was conducted using the Comprehensive Stata ver. 14 package (StataCorp, College Station, TX, United States).

Results

Seventy-two studies were included in this meta-analysis. Publication bias was compared with Egger’s test, and the impact of each research on overall estimate was evaluated by sensitivity analysis. In 56 studies, the rate of bacterial infections in the semen of infertile men was 12% [95% confidence interval (CI): 10–13]. Also, in 26 case-control studies, the association of infertility in men with bacterial infections was evaluated. The results show that the odds ratio of infertility in men exposed to bacterial infections is 3.31 times higher than that in non-infected men (95% CI: 2.60–4.23). Besides, in 9 studies that examined the prevalence of human papillomavirus (HPV), herpes simplex virus 1 (HSV1), herpes simplex virus 2 (HSV2), and herpes simplex virus 1-2 (HSV1-2) in infertile men, the frequency of these viruses was 15% (95% CI: 9–21). In 6 case-control studies, the association between human cytomegalovirus (HCMV), Cytomegalovirus (CMV), and HPV and male infertility was evaluated. The chance of male infertility due to exposure to these viruses was 2.24 times higher than those without exposure to these viruses (CI 95%: 1.9–4.52). The results show that the chance of infertility in men exposed to bacteria was significantly higher than that in the uninfected population.

Conclusion

This meta-analysis showed that viral and bacterial infections are a risk factor and could impair male fertility potential. Moreover, our study supports the hypothesis that bacterial and viral infections of the genital tract correlate positively with impairment of sperm quality in the male population.

Infertility in Men: Advances towards a Comprehensive and Integrative Strategy for Precision Theranostics

Male infertility is an increasing and serious medical concern, though the mechanism remains poorly understood. Impaired male reproductive function affects approximately half of infertile couples worldwide. Multiple factors related to the environment, genetics, age, and comorbidities have been associated with impaired sperm function. Present-day clinicians rely primarily on standard semen analysis to diagnose male reproductive potential and develop treatment strategies. To address sperm quality assessment bias and enhance analysis accuracy, the World Health Organization (WHO) has recommended standardized sperm testing; however, conventional diagnostic and therapeutic options for male infertility, including physical examination and semen standard analysis, remain ineffective in relieving the associated social burden. Instead, assisted reproductive techniques are becoming the primary therapeutic approach. In the post-genomic era, multiomics technologies that deeply interrogate the genome, transcriptome, proteome, and/or the epigenome, even at single-cell level, besides the breakthroughs in robotic surgery, stem cell therapy, and big data, offer promises towards solving semen quality deterioration and male factor infertility. This review highlights the complex etiology of male infertility, especially the roles of lifestyle and environmental factors, and discusses advanced technologies/methodologies used in characterizing its pathophysiology. A comprehensive combination of these innovative approaches in a global and multi-centric setting and fulfilling the suitable ethical consent could ensure optimal reproductive and developmental outcomes. These combinatorial approaches should allow for the development of diagnostic markers, molecular stratification classes, and personalized treatment strategies. Since lifestyle choices and environmental factors influence male fertility, their integration in any comprehensive approach is required for safe, proactive, cost-effective, and noninvasive precision male infertility theranostics that are affordable, accessible, and facilitate couples realizing their procreation dream.

Getah Virus Infection Rapidly Causes Testicular Damage and Decreases Sperm Quality in Male Mice

Getah virus (GETV) is a zoonotic arbovirus that can cause infection in many animals. It can cause pyrexia and reproductive losses in animals. The objective of the study was to explore the effects of GETV on male reproductive ability. Male mice were injected with 100 × TCID50/0.1 ml in a volume of 100-μL GETV in their hindquarter muscle, resulting in decreased semen quality and testicular histopathological changes, and the virus was detected in the testes. At 0.5 dpi (day post-infection), male mice showed decreased sperm density, motility, and decreased serum testosterone concentration, an increased sperm malformation rate, vacuoles in spermatogonial cells/spermatocytes in spermatogenic tubules, and the highest virus copies in testis. At 2 dpi, the sperm density and motility reached the lowest value of 3.99 × 106/ml and 62.03%, and the malformation rate reached 43.67%. At 28 dpi, the sperm indexes of the experimental group gradually approached that of the control group, but there were still significant differences. Since then, histopathological changes have worsened, with the most severe histopathological changes at 7 dpi and gradual recovery. Up to 14 dpi, the virus was detected by qRT-PCR and immunohistochemistry, which showed that the virus was only present in the testicular interstitium. GETV infection can rapidly enter the testis of mice and reduce the semen quality of mice, which needs to be paid attention to in the prevention and control of GETV.

The COVID-19 pandemic - what have urologists learned?

On 11 March 2020, the WHO declared the coronavirus disease 2019 (COVID-19) outbreak a pandemic and COVID-19 emerged as one of the biggest challenges in public health and economy in the twenty-first century. The respiratory tract has been the centre of attention, but COVID-19-associated complications affecting the genitourinary tract are reported frequently, raising concerns about possible long-term damage in these organs. The angiotensin-converting enzyme 2 (ACE2) receptor, which has a central role in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) invasion, is highly expressed in the genitourinary tract, indicating that these organs could be at a high risk of cell damage. The detection of SARS-CoV-2 in urine and semen is very rare; however, COVID-19 can manifest through urological symptoms and complications, including acute kidney injury (AKI), which is associated with poor survival, severe structural changes in testes and impairment of spermatogenesis, and hormonal imbalances (mostly secondary hypogonadism). The effect of altered total testosterone levels or androgen deprivation therapy on survival of patients with COVID-19 was intensively debated at the beginning of the pandemic; however, androgen inhibition did not show any effect in preventing or treating COVID-19 in a clinical study. Thus, urologists have a crucial role in detecting and managing damage of the genitourinary tract caused by COVID-19.

Testosterone as a Biomarker of Adverse Clinical Outcomes in SARS-CoV-2 Pneumonia

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may affect testicles. Lower testosterone levels have been associated with worse clinical outcomes and higher mortality. Our objective was to evaluate the hypothalamic−pituitary−gonadal axis of men admitted with SARS-CoV-2 pneumonia and its link with the pneumonia-treatment intensification. Short-term changes in hormonal parameters were also assessed. Methods: Men admitted with SARS-CoV-2 pneumonia were recruited in two different hospitals in Piedmont, Italy. In all patients, the assessment of total testosterone (TT), calculated free testosterone (cFT), gonadotropins, inhibin B (InhB), and other biochemical evaluations were performed at admission (T0) and before discharge (T1). Through a review of medical records, clinical history was recorded, including data on pneumonia severity. Results: Thirty-five men (median age 64 [58−74] years) were recruited. Lower TT and cFT levels at T0 were associated with CPAP therapy (p = 0.045 and 0.028, respectively), even after adjusting for age and PaO2/FIO2 ratio in a multivariable analysis. In those discharged alive, lower TT and cFT levels were associated with longer hospital stay (p < 0.01). TT, cFT, and InhB were below the normal range at T0 and significantly increased at T1 (TT 1.98 [1.30−2.72] vs. 2.53 [1.28−3.37] ng/mL, p = 0.038; cFT (0.0441 [0.0256−0.0742] vs. 0.0702 [0.0314−0.0778] ng/mL, p = 0.046; InhB 60.75 [25.35−88.02] vs. 77.05 [51.15−134.50], p < 0.01). Conclusions: Both TT and cFT levels are associated with adverse clinical outcomes in men admitted with SARS-CoV-2 pneumonia. As TT, cFT and InhB levels increase before discharge, short-term functional recovery of steroidogenesis and an indirect improvement of spermatozoa functional status could be hypothesized.

The Microbiome, an Important Factor That Is Easily Overlooked in Male Infertility

Humankind has been interested in reproduction for millennia. Infertility, in which male factors contribute to approximately 50%, is estimated to concern over 72 million people worldwide. Despite advances in the diagnosis, medical treatment, and psychosocial management of male infertility over the past few decades, approximately 30% of male infertility is still thought to be idiopathic. Despite emerging advances in the microbiome associated with male infertility have indicated that the microbiome may be a key factor to the management of male infertility, roles, and mechanisms of the microbiome remain ambiguous. Here, we mainly discussed the association between microbial infection in the genital tract and male infertility, effect of antimicrobial therapy on male reproduction, association between microbial dysbiosis and male infertility, and effect of probiotic intervention on male reproduction. This review made progress toward establishing a relationship between the microbiome and male infertility, and explored the role of the microbiome in male infertility. We call for more high-quality studies to focus on the relationship between microbes and male infertility, and strongly suggest increasing awareness among sterile males with microbial infection and/or microbial dysbiosis when they seek fertility help.

SARS-CoV-2 and its Implications for the Human Reproductive System: A Review Article

Context: The SARS-CoV-2 virus causes dysfunction of vital organs in the body. Concerns about the destructive effect of SARS-CoV-2 on human reproductive tissues and fertility have increased. Evaluation of the possible mechanisms by which SARS-CoV-2 causes infertility is essential for effective prevention and treatment. This review aims to assess the studies that have been conducted on SARS-CoV-2 impacts on the human reproductive system. Evidence Acquisition: This review study investigated articles indexed in PubMed, Science-Direct, Scopus, and google scholar databases from 2019 to 2021. The Keywords SARS-CoV-2, COVID-19, human reproductive system, testis, and ovary were searched in the mentioned databases. Results: The present study assessed the expression of SARS-CoV-2-specific receptors, the presence of the virus in the human reproductive system, and the mechanisms by which this virus can affect human fertility. Conclusions: SARS-CoV-2, like other viruses, may indirectly influence the male reproductive system through cytokine storms, inflammation-causing oxidative stress, and its possible complications. The direct effects of SARS-CoV-2 on the male reproductive system are also reported. The testis may be a potential target for the SARS-CoV-2 virus. The impact of the SARS-CoV-2 virus on women's reproductive performance is unknown and requires further investigation.

Semen Proteomics of COVID-19 Convalescent Men Reveals Disruption of Key Biological Pathways Relevant to Male Reproductive Function

A considerable section of males suffered from COVID-19, with many experiencing long-term repercussions. Recovered males have been documented to have compromised fertility, albeit the mechanisms remain unclear. We investigated the impact of COVID-19 on semen proteome following complete clinical recovery using mass spectrometry. A label-free quantitative proteomics study involved 10 healthy fertile subjects and 17 COVID-19-recovered men. With 1% false discovery rate and >1 unique peptide stringency, MaxQuant analysis found 1099 proteins and 8503 peptides. Of the 48 differentially expressed proteins between the healthy and COVID-19-recovered groups, 21 proteins were downregulated and 27 were upregulated in COVID-19-recovered males. The major pathways involved in reproductive functions, such as sperm-oocyte recognition, testosterone response, cell motility regulation, adhesion regulation, extracellular matrix adhesion, and endopeptidase activity, were downregulated in COVID-19-recovered patients according to bioinformatics analysis. Furthermore, the targeted approach revealed significant downregulation of semenogelin 1 and prosaposin, two proteins related to male fertility. Therefore, we demonstrate the alteration of semen proteome in response to COVID-19, thus disrupting the male reproductive function despite the patient's clinical remission. Hence, to understand fertility-related biological processes triggered by this infection, a protracted evaluation of the consequences of COVID-19 in recovered men is warranted.

The impact of COVID-19 on the male genital tract: a qualitative literature review of sexual transmission and fertility implications

The angiotensin-converting enzyme 2 receptor (ACE2) appears to be widely expressed in cells in the testes, predominantly in spermatogonia, Sertoli cells, and Leydig cells, and its co-expression with transmembrane protease serine 2 (TMPRSS2) is essential for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For this reason, the male reproductive system could be considered a potential target for SARS-CoV-2, as well as a possible reservoir of infection. However, to date, there is very little evidence about the presence of SARS-CoV-2 in semen and testicular samples. The aim of this paper was to review the current evidence regarding the impact of SARS-CoV-2 on male fertility and sexual health, with a particular focus on reproductive hormones, the presence of the virus in seminal fluid and testis, and its impact on fertility parameters. We found very limited evidence reporting the presence of SARS-CoV-2 in semen and testicular samples, and the impact of SARS-CoV-2 on reproductive hormones and fertility parameters is unclear. The quality of the examined studies was poor due to the small sample size and several selection biases, precluding definitive conclusions. Hence, future well-designed prospective studies are needed to assess the real impact of SARS-CoV-2 on male reproductive function.

Viral Infections and Male Infertility: A Comprehensive Review of the Role of Oxidative Stress

Viral infections have been a part of human existence to date, though viruses have posed a huge threat with various outbreaks lately. These threats are associated with reproductive health challenges, especially male infertility. The prime focus of this review is to highlight the mechanisms associated with viral infection-induced male infertility/subfertility and identify new treatment strategies with the aim to preserve male fertility. The reviewed data showed that viral infections stimulate inflammatory responses, resulting in the release of proinflammatory cytokines, which induces oxidative stress. This oxido-inflammatory cycle could continue in a vicious cycle and threaten male fertility. Existing data from human and experimental studies show that viral infection-induced oxido-inflammatory response results in testicular damage, atrophy of the seminiferous tubules and Sertoli cells, and reduced Leydig cell mass. This is accompanied by reduced circulatory testosterone, impaired spermatogenesis, reduced sperm motility, lipid peroxidation, DNA fragmentation and apoptosis of the sperm cells. Based on the available pieces of evidence, antioxidant therapy, in vivo and in vitro, may be beneficial and protects against the potential risk of male infertility from viral infection. It is, however recommended that more clinical studies be conducted to demonstrate the possible protective roles of antioxidants used as adjuvant therapy in viral infections, and in the in vitro treatment of semen samples for those utilizing semen washing and artificial reproductive techniques.

Triglycerides/Glucose Index is Associated with Sperm Parameters and Sperm DNA Fragmentation in Primary Infertile Men: A Cross-Sectional Study

Study question: we aimed to investigate the relationship between the tyg index and both semen and hormonal characteristics in a cohort of primary infertile men. Summary answer: almost one in two primary infertile men presented with a triglycerides/glucose index (tyg) suggestive of insulin resistance (ir). overall, patients with tyg suggestive of ir showed worse clinical, hormonal, and semen parameters. What is already known: male factor infertility (MFI) is often associated with metabolic disorders such as diabetes mellitus and metabolic syndrome, where insulin resistance (IR) plays a relevant pathological role. Recently, TyG has been suggested as a user-friendly IR marker. Study Design: serum hormones and the sperm DNA fragmentation index (SDF) were measured in every patient. The semen analysis was based on 2010 WHO reference criteria. Glucose and insulin levels were measured for every man after a 12-h overnight fast, and the homeostatic model assessment index (HOMA-IR) was then calculated and categorized using a 2.6 threshold. Similarly, fasting glucose and triglycerides levels were measured and the TyG index was calculated and categorized using an 8.1 threshold. Descriptive statistics and logistic regression models tested the association between the TyG and semen and hormonal characteristics. Participants: complete demographic, clinical, and laboratory data from 726 consecutive white European primary infertile men were considered for this analysis. Main results and the role of chance: the median (IQR) age was 39 (35–43) years. A TyG and HOMA suggestive for IR was found in 339 (46.6%) and 154 (21.2%) men, respectively. During the Spearman’s test, the TyG index was highly correlated with HOMA-IR (rho = 0.46, p < 0.001). Compared to men with a normal TyG, men with TyG > 8.1 were older, had greater BMI and CCI scores, and lower total testosterone and sperm concentration, but higher DFI, and presented a greater proportion of NOA (all p < 0.01). The multivariable logistic regression analysis showed that men with TyG > 8.1 were at higher risk of SDF > 30 (OR 1.92 (CI: 1.2–2.9)) and NOA (OR 1.78 (CI: 1.1–2.8)). Wider implications of the findings: the Tyng index may act as a reliable marker of IR in the clinical work-up of primary infertile men in real-life settings.

Association of the human semen DNA virome with successful in vitro fertilization

OBJECTIVE

To comprehensively characterize the DNA virome in semen samples collected for in vitro fertilization (IVF).

DESIGN

A descriptive clinical study.

SETTING

Single academic fertility center.

PATIENT(S)

Twenty-four male partners from couples undergoing IVF.

INTERVENTION(S)

Couples were randomized to receive 1 g of azithromycin (standard of care) or no azithromycin at the time of baseline IVF assessment. Semen samples were collected at the time of the female partners' egg retrieval, and 100 μL of the sample was used for the virome analysis.

MAIN OUTCOME MEASURE(S)

Detection of viruses by ViroCap enrichment of viral nucleic acid and sequencing. Association between the virome, semen parameters, and pregnancy outcomes.

RESULT(S)

We detected viruses in 58% of the participants. Viruses included polyomaviruses, papillomaviruses, herpesviruses, and anelloviruses. Viromes detected in semen had little overlap with the viromes detected in vaginal samples from their female partners collected at the time of embryo transfer, which were analyzed in a previous study. A lower viral diversity in semen samples was positively associated with pregnancy (Hodges-Lehmann estimate of difference, 1; 95% confidence interval, 2-0.00003). There was no association between viral diversity and sperm concentration, motility, or fertilization rates.

CONCLUSION(S)

This comprehensive characterization of the DNA virome in semen reveals an association between virome diversity and pregnancy in couples undergoing IVF. However, no association was found with specific semen parameters or fertilization rates, suggesting that viral exposure may negatively affect pregnancy after fertilization. Future studies should be undertaken to evaluate the associations between the semen virome with IVF outcomes in larger cohorts.

Implications of RNA Viruses in the Male Reproductive Tract: An Outlook on SARS-CoV-2

Emerging viral infections continuously pose a threat to human wellbeing. Several RNA viruses have managed to establish access to the male reproductive tract and persist in human semen. The sexual transmission of the virus is of critical public concern. The epidemiological inferences are essential to understand its complexity, particularly the probability of viral transmission from asymptomatic patients or those in the incubation period or from the patient who was previously infected and now fully recovered. From the clinical perspective, negative impacts in the male reproductive tract associated with RNA virus infection have been described, including orchitis, epididymitis, impaired spermatogenesis, and a decrease in sperm quality, which can affect male fertility at different time intervals. The disruption of anatomical barriers due to inflammatory responses might enable the viral invasion into the testis, and the immune privilege status of testes might facilitate a sustained persistence of the virus in the semen. In this review, the current knowledge about other RNA viruses that affect male reproductive health provides the framework to discuss the impact of the SARS-CoV-2 pandemic. The molecular mechanisms, sexual transmission, and viral impacts for mumps, HIV, Zika, and Ebola viruses are explored. We discuss the currently available information on the impact of SARS-CoV-2 and its sequelae in the male reproductive tract, particularly regarding presence in semen, its impact on sexual organs, and sperm quality. To date, no sexual transmission of SARS-CoV-2 has been reported, whereas the identification of viral particles in semen remains conflicting. In the purview of the earlier conducted analyses, it is essential to investigate further the long-term health impacts of SARS-CoV-2 on the male reproductive tract.

Implications of testicular ACE2 and the renin-angiotensin system for SARS-CoV-2 on testis function

Although many studies have focused on SARS-CoV-2 infection in the lungs, comparatively little is known about the potential effects of the virus on male fertility. SARS-CoV-2 infection of target cells requires the presence of furin, angiotensin-converting enzyme 2 (ACE2) receptors, and transmembrane protease serine 2 (TMPRSS2). Thus, cells in the body that express these proteins might be highly susceptible to viral entry and downstream effects. Currently, reports regarding the expression of the viral entry proteins in the testes are conflicting; however, other members of the SARS-CoV family of viruses - such as SARS-CoV - have been suspected to cause testicular dysfunction and/or orchitis. SARS-CoV-2, which displays many similarities to SARS-CoV, could potentially cause similar adverse effects. Commonalities between SARS family members, taken in combination with sparse reports of testicular discomfort and altered hormone levels in patients with SARS-CoV-2, might indicate possible testicular dysfunction. Thus, SARS-CoV-2 infection has the potential for effects on testis somatic and germline cells and experimental approaches might be required to help identify potential short-term and long-term effects of SARS-CoV-2 on male fertility.

Effects of COVID-19 and mRNA vaccines on human fertility

The coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has precipitated a global health crisis of unprecedented proportions. Because of its severe impact, multiple COVID-19 vaccines are being rapidly developed, approved and manufactured. Among them, mRNA vaccines are considered as ideal candidates with special advantages to meet this challenge. However, some serious adverse events have been reported after their application, significantly increasing concerns about the safety and efficacy of the vaccines and doubts about the necessity of vaccination. Although several fertility societies have announced that COVID-19 mRNA vaccines are unlikely to affect fertility, there is no denying that the current evidence is very limited, which is one of the reasons for vaccine hesitancy in the population, especially in pregnant women. Herein, we provide an in-depth discussion on the involvement of the male and female reproductive systems during SARS-CoV-2 infection or after vaccination. On one hand, despite the low risk of infection in the male reproductive system or fetus, COVID-19 could pose an enormous threat to human reproductive health. On the other hand, our review indicates that both men and women, especially pregnant women, have no fertility problems or increased adverse pregnancy outcomes after vaccination, and, in particular, the benefits of maternal antibodies transferred through the placenta outweigh any known or potential risks. Thus, in the case of the rapid spread of COVID-19, although further research is still required, especially a larger population-based longitudinal study, it is obviously a wise option to be vaccinated instead of suffering from serious adverse symptoms of virus infection.

Semen parameters in men recovered from COVID-19: a systematic review and meta-analysis

BACKGROUND

The novel beta-coronavirus disease (COVID-19) has infected millions of people globally with high risk among males than females. However, the effect of COVID-19 andrology is still a subject of dispute. We planned to analyze the overall consequences of COVID-19 on semen parameters and male sex hormones.

MAIN TEXT

Systematic search was performed on MEDLINE and Scopus database until 11 June 2021. We included observational studies, which reported mean ± standard deviation of the semen parameters and serum sex hormones of those reproductive-aged males recovered from COVID-19 and controls who did not suffered from COVID-19. We used Random-effect model to pool the studies, as heterogeneity was present. The Q test and I 2 evaluated heterogeneity. All articles were assessed with their quality and publication bias.We assessed 966 articles for eligibility and found seven eligible studies. These 7 studies included 934 participants with mean age 37.34 ± 10.5 years. Random-effect model meta-analysis showed that men who recovered from COVID-19 had semen parameters less than those who had not suffered from COVID-19. The overall mean difference (MD) [95% confidence interval (CI)] in semen volume, sperm concentration, sperm number, and progressive sperm motility was - 0.20 (- 0.45, 0.05) ml, - 16.59 (- 34.82, 1.65) millions/ml, - 45.44 (- 84.56, - 6.31) millions per ejaculate, - 1.73 (- 8.20, 4.75) percentage respectively. Considering sex hormones, luteinizing hormone and prolactin levels were higher among those recovered with a significant MD (95% CI) of 3.47 (1.59, 5.35)U l-1 and 3.21 (1.71, 4.72)ng ml-1 respectively.

CONCLUSION

We found that COVID-19 affects both semen parameters and sexual hormones. However, the mechanism for testicular involvement remains doubtful.

TRIAL REGISTRATION

PROSPERO CRD42021259445.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1186/s43043-021-00089-w.

COVID-19 and urology: A bibliometric analysis of the literature

AIM

The aims of this research were to analyse the urological literature published during the COVID-19 pandemic and to guide future research.

MATERIAL AND METHODS

Between 2019 and 2021, the Web of Science (WoS) All Databases collection was searched for publications related to COVID-19 and Urology. The keywords used during this search were coronavirus-19, COVID-19, SARS-CoV-2, novel coronavirus, 2019-nCoV, pandemic and/or urology. The top 50 cited (T50) publications were also identified and summarized. Exported Microsoft Excel files, Visualization of Similarities viewer (VOSviewer) software and descriptive assessment were used for bibliometric and statistical analyses of the publications.

RESULTS

In total, 582 publications related to COVID-19 and urology were identified. In these publications, the most active author, journal, country and organisation were Francesco Porpiglia, European Urology, the United States of America (USA) and La Paz University Hospital, respectively. The most commonly used keywords were telemedicine-telehealth, SARS-CoV-2, coronavirus, pandemic, residency, testicle, semen, kidney transplantation, endourology and surgery. The most worrying issues in the articles are the negative impact of COVID-19 on resident training and permanent damage to urological organs.

CONCLUSIONS

We analysed all the articles related to COVID-19 and urology published to date in the WoS All Databases collection. The most commonly published articles were based on clinical and outpatient practice, telemedicine, residency training, transplantation, and testicles. The long-term adverse effects of the pandemic on urology practice and especially urological organs will need to be assessed further in future research.

Differential Effects of Viral Nucleic Acid Sensor Signaling Pathways on Testicular Sertoli and Leydig Cells

The human testis can be infected by a large number of RNA and DNA viruses. While various RNA virus infections may induce orchitis and impair testicular functions, DNA virus infection rarely affects the testis. Mechanisms underlying the differential effects of RNA and DNA viral infections on the testis remain unclear. In the current study, we therefore examined the effects of viral RNA and DNA sensor signaling pathways on mouse Sertoli cells (SC) and Leydig cells (LC). The local injection of viral RNA analogue polyinosinic-polycytidylic acid [poly(I:C)] into the testis markedly disrupted spermatogenesis, whereas the injection of the herpes simplex virus (HSV) DNA analogue HSV60 did not affect spermatogenesis. Poly(I:C) dramatically induced the expression of the proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 6 in SC and LC through Toll-like receptor 3 and interferon β promoter stimulator 1 signaling pathways, impairing the integrity of the blood-testis barrier and testosterone synthesis. Poly(I:C)-induced TNF-α production thus plays a critical role in the impairment of cell functions. In contrast, HSV60 predominantly induced the expression of type 1 interferons and antiviral proteins via the DNA sensor signaling pathway, which did not affect testicular cell functions. Accordingly, the Zika virus induced high levels of TNF-α in SC and LC and impaired their respective cellular functions, whereas Herpes simplex virus type 2 principally induced antiviral responses and did not impair such functions. These results provide insights into the mechanisms by which RNA viral infections impair testicular functions.

SARS-CoV-2 effect on male infertility and its possible pathophysiological mechanisms

First case of COVID-19 was reported in Wuhan, China in December 2019. As of now, May 2021, a total of 164,189,004 people were infected, and 3,401,990 deaths have occurred caused by SARS-CoV-2. As SARS-CoV-2 virus cell entry mainly depends on the ACE2 and TMPRSS2 proteins, the presence of high expression levels of both ACE2 and TMPRSS2 in testes highlights the possible vulnerability of men to the virus. Other RNA viruses frequently induce orchitis and result in male infertility. This review evaluates the decline in male fertility and a total of 48 original articles were included for the analysis. We investigated the effects of COVID-19 on male reproductive health and male fertility.  There is a strong association between the high number of ACE2 receptors in the testes and the COVID-19 viral loads. SARS-CoV-2 infection negatively affects the male reproductive tract. Human biological tissues, including body fluids and excretions, tissues, and organs showed positive results tests for SARS-CoV-2. A disruption in the balance of male reproductive system hormones is also observed. Male gonads may be potentially vulnerable to SARS-CoV-2 infection, suggesting caution to follow-up and evaluate infected men that have plans to conceive. Further studies are required to determine if this impairment is temporary or permanent, elucidate SARS-CoV-2’s entrance strategies into the testis and how it can affect the semen quality and quantity. We recommend a post-infection follow-up, especially in male patients of reproductive age already having fertility issues.

Male fertility as a marker for health

Male reproduction is a complex biological process, and male factor infertility is increasingly recognized as a biomarker for overall male health. Emerging data suggest associations between male reproduction and medical disease (genetic, infectious, chronic comorbid conditions), psychological disease, environmental exposures, dietary habits, medications and substances of abuse, and even socioeconomic factors. There is also evidence that a diagnosis of male fertility is associated with future disease risk including cancer, metabolic disease and mortality. As such, there is a growing view that the male fertility evaluation is an opportunity to improve a man's health beyond his immediate reproductive goals, and also highlights the necessity of a multidisciplinary approach.

Relative frequency of hepatitis B virus, human papilloma virus, Epstein-Barr virus, and herpes simplex viruses in the semen of fertile and infertile men in Shiraz, Iran: A cross-sectional study

Background

About 8-12% of couples on reproductive age suffers from infertility worldwide. Since 1993, the role of genital tract infections by microbes, including viruses that can infect the sperm, in human infertility has been proposed.

Objective

To investigate the frequency of hepatitis B virus (HBV), human papilloma virus (HPV), Epstein-Barr virus (EBV), and herpes simplex virus (HSV) infection in the semen of fertile and infertile men referred to the Mother and Child Hospital, Shiraz, Iran.

Materials and Methods

In this cross-sectional study, 350 men including 200 infertile and 150 fertile men were included. All semen samples were allowed to liquefy, followed by the assessment of sperm parameters. DNA was extracted using a DNA extraction kit (CinaGene, Tehran, Iran) according to the manufacturer's instructions. Detection of HBV, HPV, EBV, and HSV1/2 was done by the PCR method.

Results

The mean age of the participants was 36 ± 7 yr. Molecular results showed that 16 samples (8%) of infertile men and 5 (3.3%) of fertile men were positive for HBV, which was not statistically significant (p = 0.069). Only one sample of the fertile participants was positive for HPV. None of the semen samples of the infertile or fertile groups was positive for the presence of EBV or HSV1/2.

Conclusion

The results of this study indicated that HBV, HPV, EBV, and HSV might not be involved in men's infertility. Further studies are recommended for clarifying the role of these viruses in infertility.

Unique Tropism and Entry Mechanism of Mumps Virus

Mumps virus (MuV) is an important human pathogen that causes parotitis, orchitis, oophoritis, meningitis, encephalitis, and sensorineural hearing loss. Although mumps is a vaccine-preventable disease, sporadic outbreaks have occurred worldwide, even in highly vaccinated populations. MuV not only causes systemic infection but also has a unique tropism to glandular tissues and the central nervous system. In general, tropism can be defined by multiple factors in the viral life cycle, including its entry, interaction with host factors, and host-cell immune responses. Although the underlying mechanisms of MuV tropism remain to be fully understood, recent studies on virus-host interactions have provided insights into viral pathogenesis. This review was aimed at summarizing the entry process of MuV by focusing on the glycan receptors, particularly the recently identified receptors with a trisaccharide core motif, and their interactions with the viral attachment proteins. Here, we describe the receptor structures, their distribution in the human body, and the recently identified host factors for MuV and analyze their relationship with MuV tropism.

Possible Male Reproduction Complications after Coronavirus Pandemic

Coronavirus disease 2019 (COVID-19), as a severe respiratory disease, affects various tissues and organs. The specific SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2), is highly expressed in male gonads. Thus, male reproductive tissues could be a potential target for virus colonization. We performed a comprehensive search in PubMed and Google Scholar to retrieve relevant articles published till 15 April 2021. The keywords used were: male fertility, male reproductive health, semen parameters, sex hormones, SARS-CoV-2, and COVID-19. Validated evidence about the adverse effects of the SARS-CoV-2 infection on the male reproductive system is limited and few studies have reported semen analysis results or presence of viral RNA in semen samples of infected men. Nevertheless, alterations in reproductive hormones such as decreased level of testosterone (T) with raised luteinizing hormone (LH) have been reported in some patients. Although the impact of SARS-CoV-2 infection on the male reproduction health remains unclear, evidence suggests that male gonads may be potentially vulnerable to SARS-CoV-2 infection. In this article, we discussed the possible impacts of COVID-19 on male gonads, sex hormones, and semen quality and suggested preventive solutions.

The impact of COVID-19 on the male reproductive tract and fertility: A systematic review

OBJECTIVE

The COVID-19 pandemic, caused by the acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), remains an ongoing public health challenge. Although males are affected slightly more than females, the impact of SARS-COV-2 on male reproductive system remains unclear. This systematic review aims to provide a concise update on the effects of COVID-19 on male reproductive health, including the presence of viral RNA in semen, and the impact on semen quality, testicular histology, testicular pain and male reproductive hormones. The global health is fronting an immediate as well as impending threat from the novel coronavirus (SARS-CoV-2) causing coronavirus disease (COVID-19), that inflicts more males than females. Evidence suggest that male reproductive system is susceptible to this viral infection. However, there are still several pertinent queries that remain to be fully explained regarding the mechanism in testicular SARS-CoV-2 dynamics and the exact mode of its actions. Thus, the present systematic review aims to provide a concise update on the effects of coronavirus disease 2019 (COVID-19) on male reproduction..

METHODS

A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines searching the PubMed database. Eligibility for inclusion were original human studies evaluating the impact of COVID-19 on male reproductive health. Specific outcomes required for inclusion were at least one of the following: i) seminal detection of mRNA virus, or evaluation of ii) semen analysis, iii) testicular histology or ultrasonography, iv) testicular clinical symptoms and/or v) male reproductive hormones in COVID-19-positive patients.

RESULTS

Of 553 retrieved articles, 25 met the inclusion criteria. This included studies primarily investigating the presence of viral RNA in semen (n = 12), semen quality (n = 2), testicular histology (n = 5), testicular pain (n = 2) and male reproductive hormones (n= 4). Results show little evidence for the presence of viral RNA in semen, although COVID-19 seems to affect seminal parameters, induce orchitis, and cause hypogonadism. Mortality cases suggest severe histological disruption of testicular architecture, probably due to a systemic and local reproductive tract inflammatory response and oxidative stress-induced damage.

CONCLUSIONS

Clinical evaluation of the male reproductive tract, seminal parameters and reproductive hormones is recommended in patients with current or a history of COVID-19, particularly in males undergoing fertility treatment. Any long-term negative impact on male reproduction remains unexplored and an important future consideration.

Effects of moderate COVID-19 infection on semen oxidative status and parameters 14 and 120 days after diagnosis

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus causing coronavirus disease 2019 (COVID-19). Because COVID-19 is a multisystem infection, there are some concerns regarding its possible effects on male fertility. This study aimed to investigate the effects of COVID-19 on semen oxidative status and parameters 14 and 120 days after diagnosis in patients presenting with moderate infection (defined as respiratory symptoms, with or without fever, with Spo2 <93% and >90% and lung involvement <50%). Semen samples were obtained from 20 participants at two time points: the first sample on Day 14 and the second on Day 120 after diagnosis. Semen parameters (sperm concentration, motility, morphology, and viability) were evaluated, as were levels of seminal reactive oxygen species (ROS), malondialdehyde (MDA), total antioxidant capacity (TAC) and sperm DNA fragmentation. Semen parameters, including sperm motility and DNA integrity, improved at 120 days after the COVID-19 diagnosis relative to values at 14 days. In addition, ROS and MDA levels were significantly reduced in patients 120 days after infection, and TAC increased at 120 days compared with 14 days (during the acute stage of infection). In conclusion, the present study shows that the detrimental effects of COVID-19 on sperm properties caused by oxidative stress decrease up to Day 120 after diagnosis.