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.

Detection of Chlamydia trachomatis inside spermatozoa using flow cytometry: Effects of antibiotic treatment (before and after) on sperm count parameters

There is increasing evidence that Chlamydia trachomatis (CT) infection can directly affect male fertility. However, only few have investigated the effects of CT on semen parameters, and mostly with inconclusive results. The main aims of this study were to identify CT inside spermatozoa, and the possible pre and post antibiotic treatment effects on the overall semen parameters. We developed a flow cytometric method for the detection of CT inside spermatozoa (SPI™). Briefly, sperm cells were fixed, membrane permeabilized and DNA was loosened using DNAse. Sperm cells were incubated with a primary monoclonal antibody against CT and with a secondary fluorescent antibody (vs primary), and analysed using a flow cytometer. Of 2415 infertile individuals, 48.61% were found positive for CT. 170 CT+ samples were included in the CT antibiotic treatment study. 78.82% (134/170) of the CT+ showed a significant reduction in the percentage of the iCT infected spermatozoa after the antibiotic treatment; 59.70% (80/134) decreased to non-detectable levels. Spermcount data were also recorded. Spermatozoa morphology (normal and teratozoospermia index, TZI) and motility (fast progressive and non-progressive spermatozoa) were statistically significant altered in CT+ pre-treatment vs control group. CT antibiotic treatment showed statistically significant effects on normal spermatozoa morphology, mid-piece and tail defects, and TZI. The study demonstrated that semen flow cytometric analysis of semen could be a valuable tool for faster and accurate identification of individuals with asymptomatic CT infection. It also identified a positive effect of antibiotic therapy on semen parameters, that could help males with infertility.

The negative impact of most relevant infections on fertility and assisted reproduction technology

Infections may act with variable impact on the physiopathology of the reproductive organs, determining infertility or reducing the outcomes of assisted reproduction technology. The aim of this narrative review is to describe the existing evidence regarding the pathogens with a supposed or recognized role in reproductive medicine. Viral hepatitis, as well as HIV, can reduce sperm quality. Syphilis carries a risk of erectile dysfunction and increased endometrial thickness. Chlamydia is the main cause of pelvic inflammatory disease. In relation to Mycoplasma and Ureaplasma spp., only few species seem to show a correlation with infertility and poor in-vitro fertilization outcomes. There is evidence of a role for bacterial vaginosis in early pregnancy loss. HPV infection in males seems to determine infertility. Herpesviruses are more a risk for fetuses than for fertility itself. Zika virus is responsible for altered early embryo development and waiting to conceive is recommended in suspected or confirmed cases. The impact of SARS-CoV-2 is yet to be elucidated. Rubella and toxoplasmosis can provoke important congenital defects and therefore screening is mandatory before conception; a vaccine for Rubella is recommended. Further and well-designed studies are still needed to better elucidate the role of some infectious agents, to improve fertility and its treatments.

Rheotaxis-based microfluidic device for selecting sperm from samples infected with a virus

OBJECTIVE

To investigate whether the presented rheotaxis-based microfluidic device could be used to separate spermatozoa from viruses (i.e., Zika) in the infected semen sample during the selection and washing process.

DESIGN

Quantitative and experimental study of the sperm washing/selection process through the microfluidic platform exploiting the positive rheotaxis of sperm.

SETTING

None.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Human sperm were purchased from a sperm bank. The raw semen sample was mixed with viruses and loaded into a microfluidic device. Experiments were performed with 2 different flow rates (0 and 25 μL/minute) to investigate the washing efficiency of the device in the sperm selection process. The sperm sample was collected after 45 minutes and analyzed to check whether the collected sample is free of any infections (viruses) after isolation.

RESULT(S)

Fluorescent microscopy and quantitative polymerase chain reaction-based analysis showed that the sperm selected with the presented rheotaxis-based microfluidic device at the optimal flow rate (25 μL/minute) was free of any viruses.

CONCLUSION(S)

We have developed a simple, cost-effective microfluidic device that mimics the conditions of the female genital tract while washing out the raw semen efficiently during the selection process for assisted reproductive technology.

The evaluation of Human papilloma virus and human herpes viruses (EBV, CMV, VZV HSV-1 and HSV-2) in semen samples

There are a number of risk factors, especially viral diseases, which can lead to infertility. Among the various viral infections, much attention has been given to the role of the Papillomaviridae and Herpesviridae. After collecting 82 semen samples (37 teratospermia, 2 asthenozoospermia, 2 oligoasthenospermia, 1 oligospermia, 6 asthenoteratospermia and 34 normal semen samples), and washing them, the DNA from both freshly ejaculated spermatozoon and washed spermatozoa was extracted. Subsequently, the prevalence of EBV, CMV, HSV-1, HSV-2, VZV and HPV was evaluated using Multiplex PCR and Nested PCR. In this study, 1 normal and 5 abnormal semen samples were infected with HSV-1 (1 normal, 4 teratospermia and 1 oligoasthenospermia). In addition, there were 2 VZV-positive samples (both were teratozoospermia). Nested PCR indicated that 1 asthenozoospermia, 1 asthenoteratospermia, 3 teratospermia and 4 normal samples were HPV positive (including 8 HPV-18 and 1 HPV-33). Among 9 HPV-positive subjects, 3 samples were negative after washing the infected samples. The prevalence of EBV, CMV, VZV, HSV-1 and HSV-2 remained unchanged prior to and after washing. Maybe sperm washing can be useful to eliminate HPV infection from semen samples, but further investigation is required because of the small number of samples.

The Good, the Bad and the Ugly of Testicular Immune Regulation: A Delicate Balance Between Immune Function and Immune Privilege

The testis is one of several immune privilege sites. These sites are necessary to decrease inflammation and immune responses that could be damaging to the host. For example, inflammation in the brain, eye or placenta could result in loss of cognitive function, vision or rejection of the semi-allogeneic fetus, respectively. In the testis, immune privilege is "good" as it is necessary for protection of the developing auto-immunogenic germ cells. However, there is also a downside or "bad" part of immune privilege, where pathogens and cancers can take advantage of this privilege and persist in the testis as a sanctuary site. Even worse, the "ugly" of privilege is how re-emerging viruses, such as Ebola and Zika viruses, can establish persistence in the testes and be sexually transmitted even months after they have been cleared from the bloodstream. In this review, we will discuss the delicate balance within the testis that provides immune privilege to protect the germ cells while still allowing for immune function to fight off pathogens and tumors.

Improvement of Sperm Quality in Hyperviscous Semen following DNase I Treatment

Semen hyperviscosity impairs sperm motility and can lead to male infertility. This prospective study aimed at assessing the ability of exogenous DNase in improving sperm quality, taking into consideration that DNase has been found in the seminal plasma of several species and that neutrophils release chromatin in order to trap bacteria. A total of seventy-seven semen samples with high seminal viscosity (HSV) as the study group and sixty-two semen samples with normal seminal viscosity (NSV) as the control group were compared in this analysis. These semen samples were divided into three groups of receiving treatment (a) with DNase I at 37°C for 15 min, (b) by density gradient centrifugation, and (c) with a combination of the above two methods. Following a fifteen-minute treatment of hyperviscous semen, the motility of spermatozoa in 83% of semen samples increased to a statistically significant degree. On the contrary, DNase treatment of semen with normal viscosity had no such effects. The above treatment was also accompanied by a significant increase in the percentage of normal spermatozoa, resulting in a major decrease of the teratozoospermia index. Comparison between semen samples that underwent density gradient centrifugation following DNase I treatment, to those collected after density gradient treatment alone, showed that in the first case the results were more spectacular. The evaluation of each preparation in terms of yield (% total progressively motile sperm count after treatment in relation to the initial total sperm count) revealed that the combined approach resulted in 29.8% vs. 18.5% with density treatment alone (p=0.0121). DNase I treatment results in an improvement of sperm motility and morphology and could be beneficial to men with hyperviscous semen in assisted reproduction protocols.

A new micro swim-up procedure for sperm preparation in ICSI treatments: preliminary microbiological testing

Objective

This study aimed to assess the levels of microbial contamination in semen samples before and after the micro swim-up (MSU) procedure in intra-cytoplasmic sperm injection (ICSI). The new method is an upgrade to the classic wash swim-up procedure.

Methods

Semen analysis and microbiological tests were carried out before and after the MSU procedure. A total of twenty semen samples were analyzed.

Results

Pathogens were observed in semen samples only before MSU and never after ICSI. Microbiological tests revealed a large prevalence of gram-positive cocci [Staphylococcus spp. (n=16, 80%) and viridans streptococci (n=10, 50%)]. The results of this study indicate that direct MSU in ICSI improved the ICSI workflow.

Conclusion

The new workflow is faster and more affordable, and is likely to prevent infection problems that could arise from the normal microbial flora of the semen.

[Interaction of herpesviruses with mature human spermatozoa in the model system in vitro]

The DNA of human herpesviruses (HHV), including the herpes simplex virus (HSV) and cytomegalovirus (CMV), is often identified in ejaculates of patients with urogenital diseases and infertility. At least a part of viral DNA is associated with cell fraction of ejaculate. However, it remains unclear how the semen is infected by the virus. It can be located in gametes or be capable of infecting mature germ cells, including motile sperm cells. In order to resolve this issue, interactions of the CMV and HSV with human sperm cells were studied using an original optimized model of the herpesviral infection of male gametes in vitro. The analysis of the immunofluorescent staining of gametes for viral antigens has shown that CMV infected 2% gametes, while HSV infected 17.26 ± 2.58% gametes. The fraction of progressively motile sperm cells contained 13.99 ± 4.64% infected cells. Localization of HSV was studied by the confocal microscopy. Sometimes, viral gB protein was found on sperm cell membrane. In addition, optical scanning of other cells has shown the intracellular localization of the viral proteins. In the majority of spermatozoa, the viral proteins were observed in the head and neck. In some cells, they were located in the middle piece or, rarely, in the equatorial segment. In general, after in vitro infection HSV antigens were located in the same areas of the sperm cells as in ejaculates from infected patients. According to DNA-DNA hybridization in situ, gametes containing HSV DNA accounted for 16.94 ± 5.28%, which is consistent with the results obtained in the immunofluorescence assay. It can be concluded that mature male gametes are infected by HHV in the genital tract, where the virus binds to the sperm cell membrane and enters the cell. Interaction of HHV with progressively motile sperm cells implies a vertical viral transmission upon fertilization and points to the necessity of testing ejaculate for herpesviruses infections.

Laboratory and clinical aspects of human herpesvirus 6 infections

Human herpesvirus 6 (HHV-6) is a widespread betaherpesvirus which is genetically related to human cytomegalovirus (HCMV) and now encompasses two different species: HHV-6A and HHV-6B. HHV-6 exhibits a wide cell tropism in vivo and, like other herpesviruses, induces a lifelong latent infection in humans. As a noticeable difference with respect to other human herpesviruses, genomic HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6) in about 1% of the general population. Although it is infrequent, this may be a confounding factor for the diagnosis of active viral infection. The diagnosis of HHV-6 infection is performed by both serologic and direct methods. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time PCR. Many active HHV-6 infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. However, the virus may be the cause of serious diseases, particularly in immunocompromised individuals. As emblematic examples of HHV-6 pathogenicity, exanthema subitum, a benign disease of infancy, is associated with primary infection, whereas further virus reactivations can induce severe encephalitis cases, particularly in hematopoietic stem cell transplant recipients. Generally speaking, the formal demonstration of the causative role of HHV-6 in many acute and chronic human diseases is difficult due to the ubiquitous nature of the virus, chronicity of infection, existence of two distinct species, and limitations of current investigational tools. The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active HHV-6 infections, but the indications for treatment, as well as the conditions of drug administration, are not formally approved to date. There are still numerous pending questions about HHV-6 which should stimulate future research works on the pathophysiology, diagnosis, and therapy of this remarkable human virus.

Presence of HHV-6 genome in spermatozoa in a context of couples with low fertility: what type of infection?

Human herpesvirus-6 (HHV-6) is a betaherpesvirus whose genome may integrate into human chromosomes. Chromosomally integrated HHV-6 (ciHHV-6) may be transmitted vertically from parents to children. HHV-6 DNA has been detected in semen, but its integrated or extrachromosomal status has not yet been characterised. The aim of this study was to determine the prevalence of HHV-6 DNA and to search for ciHHV-6 forms in spermatozoa purified from semen obtained from subjects explored for low fertility. A total of 184 sperm samples were purified using PureSperm(®) . HHV-6 viral load and species identification were performed by real-time polymerase chain reaction. Of 179 sperm specimens analysed, three were positive for HHV-6 (1.7%). Two samples (1.1%) had viral loads of 680 232 and 2 834 075 copies per million spermatozoa, compatible with loads expected for a ciHHV-6 form. The viral load of the third positive sample (73 684 copies per million spermatozoa) was lower than would be expected for ciHHV-6 infection, implying that the HHV-6 DNA detected in spermatozoa corresponds mainly to ciHHV-6. However, viral DNA may also be detected at a low level that is not in favour of the presence of ciHHV-6. Further studies are necessary to determine the origin of detected viral genomes.

Cytomegalovirus and human immunodeficiency virus in semen of homosexual men

OBJECTIVE

To assess the accuracy of serology to predict the presence of cytomegalovirus (CMV) in semen of homosexual men without and with HIV coinfection.

DESIGN

Semen CMV was detected by electron microscopy and by polymerase chain reaction (PCR) amplification; paired serum was tested for CMV IgG/IgM. Semen HIV was detected by reverse transcription-PCR.

SETTING

Licensed clinical and research laboratory.

PATIENT(S)

Sixty-eight men.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Frequency of CMV and HIV in semen.

RESULT(S)

Cytomegalovirus was detected by electron microscopy in 3 of 10 specimens examined. Forty-six (89%) of 52 HIV-infected men were seropositive for CMV by combined assay for IgG/IgM; two more (48 of 52, 92%) were seropositive for CMV IgG by separate assay; 25 (48%) of the HIV-infected men had PCR-detectable CMV DNA in at least one semen specimen, 22 of whom (42%) had CMV in all specimens. Nineteen (13%) of the 150 specimens tested positive for HIV, whereas 67 (45%) tested positive for CMV; seven specimens tested positive for both CMV and HIV. Cytomegalovirus, but not HIV, detection in semen correlated with decreased CD4(+) lymphocytes in peripheral blood (<700/μL) but was not accurately predicted by serology, leukocytospermia, or age.

CONCLUSION(S)

Cytomegalovirus in semen is not accurately predicted by serology. Sperm banking needs to include direct assessment of CMV in semen specimens. Strategies to eliminate CMV from semen specimens are needed to alleviate the risk of virus transmission.

Seminal shedding of human herpesviruses

Most of the human herpesviruses can be found in semen, although the reported prevalence varies considerably between individual studies. The frequent presence of herpesvirus in semen raises the question whether sexual transmission of the virus could have an impact on human reproduction. Only few studies have associated seminal shedding of herpesviruses with impaired sperm quality, reduced fertility, or reduced chances of pregnancy, whereas most studies fail to find an association. Taken together, no firm evidence is so far linking the presence of herpesviruses in semen to impaired human reproduction.

Human herpesvirus-6A/B binds to spermatozoa acrosome and is the most prevalent herpesvirus in semen from sperm donors

An analysis of all known human herpesviruses has not previously been reported on sperm from normal donors. Using an array-based detection method, we determined the cross-sectional frequency of human herpesviruses in semen from 198 Danish sperm donors. Fifty-five of the donors had at least one ejaculate that was positive for one or more human herpesvirus. Of these 27.3% (n = 15) had a double herpesvirus infection. If corrected for the presence of multiple ejaculates from some donors, the adjusted frequency of herpesviruses in semen was 27.2% with HSV-1 in 0.4%; HSV-2 in 0.1%; EBV in 6.3%; HCMV in 2.7%; HHV-6A/B in 13.5%; HHV-7 in 4.2%, whereas none of the samples had detectable VZV or HHV-8. Subsequently, we examined longitudinally data on ejaculates from 11 herpesvirus-positive donors. Serial analyses revealed that a donor who tested positive for herpesvirus at one time point did not necessarily remain positive over time. For the most frequently found herpesvirus, HHV-6A/B, we examined its association with sperm. For HHV-6A/B PCR-positive semen samples, HHV-6A/B could be detected on the sperm by flow cytometry. Conversely, PCR-negative semen samples were negative by flow cytometry. HHV-6B was shown to associate with sperm within minutes in a concentration dependent manner. Confocal microscopy demonstrated that HHV-6B associated with the sperm head, but only to sperm with an intact acrosome. Taken together, our data suggest that HHV-6A/B could be transported to the uterus via binding to the sperm acrosome. Moreover, we find a 10 times higher frequency of HHV-7 in semen from healthy individuals than previously detected. Further research is required to determine the potential risk of using herpesvirus-positive donor semen. Longitudinally analyses of ejaculate series indicate that implementation of quarantine for a donor shown to shed a herpesvirus is not a tenable solution.