Presence of human papillomavirus DNA in testicular biopsies from nonobstructive azoospermic men

Viruses, bacteria and parasites: infection of the male genital tract and fertility

BACKGROUND

Infertility affects one couple out of six worldwide. Male infertilty can result from congenital or acquired factors, of which pathogens that reach the genital tract through sexual contact or blood dissemination. The impact of major viral, bacterial and parasitic infections on the male genital tract and fertility has been summarized.

RESULTS AND CONCLUSIONS

A systematic review of articles published in the Google Scholar and PubMed databases was conducted. It turns out that viruses, as well as bacteria and parasites are major inducers of male genital tract infections and ensuing infertility through damage to the organs and subsequent loss of function and/or through direct damage to the sperm cells. Moreover, not only male infertility results from such infections but these can also be transmitted to women and even to the offspring, thus highlighting the need to efficiently detect, treat and prevent them.

Human Papillomavirus (HPV) Infection and Its Impact on Male Infertility

Nowadays, the striking numbers of infertile couples that turn to assisted reproductive technologies (ART) drive the research toward a more comprehensive understanding of the underlying causes. Male factors contribute to the inability to conceive in half of the cases, and it has been suggested that sexually transmitted infections could have a role in the onset of spermatozoa impairments. Since the impact of HPV infection on sperm quality and sperm DNA integrity is debated, we wanted to analyze its impact on conventional seminal parameters and the sperm DNA fragmentation index (DFI). Therefore, 117 semen samples of patients undergoing IVF were evaluated for the following characteristics: HPV DNA detection and sperm DNA fragmentation, concentration, motility, and morphology. The results showed a higher rate of HPV-negative patients (59.8% vs. 40.2%) and no HPV-related effect on DFI, sperm concentration, total sperm number, and total motility. Only progressive motility and morphology were found as significantly influenced by HPV positivity. Moreover, we observed a statistically significant difference in DFI when comparing high-risk HPV (HR-HPV) and low-risk HPV (LR-HPV) genotypes. Our data suggest that the presence of any HPV type, whatever the exact localization of the virions, can impair some sperm parameters, while HR-HPVs specifically affect the integrity of spermatozoa DNA.

Viral tropism for the testis and sexual transmission

The mammalian testis adopts an immune privileged environment to protect male germ cells from adverse autoimmune reaction. The testicular immune privileged status can be also hijacked by various microbial pathogens as a sanctuary to escape systemic immune surveillance. In particular, several viruses have a tropism for the testis. To overcome the immune privileged status and mount an effective local defense against invading viruses, testicular cells are well equipped with innate antiviral machinery. However, several viruses may persist an elongated duration in the testis and disrupt the local immune homeostasis, thereby impairing testicular functions and male fertility. Moreover, the viruses in the testis, as well as other organs of the male reproductive system, can shed to the semen, thus allowing sexual transmission to partners. Viral infection in the testis, which can impair male fertility and lead to sexual transmission, is a serious concern in research on known and on new emerging viruses. To provide references for our scientific peers, this article reviews research achievements and suggests future research focuses in the field.

Human papillomavirus detected in sperm of Japanese infertile males affects reproductive parameters

OBJECTIVES

The effects of human papillomavirus (HPV) infection on male reproductive parameters are currently a matter of controversy. In order to clarify the issue in Japanese infertile men, the prevalence and localization of HPV in semen, sperm parameters, and superoxide dismutase (SOD) activity in seminal plasma were examined in 216 Japanese infertile men.

METHODS

DNA was extracted from liquid-based cytological semen samples. The β-globin gene was amplified by polymerase chain reaction (PCR), and HPV-DNA was amplified using nested PCR with MY09/MY11 as outer primers and GP5+/GP6+ as inner primers. HPV genotyping was performed in the HPV-positive samples. In addition, SOD levels in seminal plasma were analysed quantitatively. In-situ hybridization (ISH) was performed to localize HPV-DNA in sperm from HPV-positive samples.

RESULTS

Any-risk and high-risk prevalence rates of HPV in semen were 12.5% and 6.9%, respectively. No significant difference in the prevalence of HPV was observed between azoospermic and non-azoospermic subjects. Among non-azoospermic patients, those with HPV detected in semen had significantly lower sperm motility and concentration compared with subjects without HPV detected in semen. SOD levels in seminal plasma were significantly higher in HPV-positive patients compared with HPV-negative patients. ISH analysis of HPV-positive samples revealed that HPV-DNA was localized to the head and mid-piece of sperm. HPV-DNA was present in the sperm of young infertile men.

CONCLUSION

HPV infection of sperm was associated with reduced sperm motility and concentration, and resulted in an increase in seminal SOD activity.

Genetic instability and anti-HPV immune response as drivers of infertility associated with HPV infection

Human papillomavirus (HPV) is a sexually transmitted infection common among men and women of reproductive age worldwide. HPV viruses are associated with epithelial lesions and cancers. HPV infections have been shown to be significantly associated with many adverse effects in reproductive function. Infection with HPVs, specifically of high-oncogenic risk types (HR HPVs), affects different stages of human reproduction, resulting in a series of adverse outcomes: 1) reduction of male fertility (male infertility), characterized by qualitative and quantitative semen alterations; 2) impairment of couple fertility with increase of blastocyst apoptosis and reduction of endometrial implantation of trophoblastic cells; 3) defects of embryos and fetal development, with increase of spontaneous abortion and spontaneous preterm birth. The actual molecular mechanism(s) by which HPV infection is involved remain unclear. HPV-associated infertility as Janus, has two faces: one reflecting anti-HPV immunity, and the other, direct pathogenic effects of HPVs, specifically, of HR HPVs on the infected/HPV-replicating cells. Adverse effects observed for HR HPVs differ depending on the genotype of infecting virus, reflecting differential response of the host immune system as well as functional differences between HPVs and their individual proteins/antigens, including their ability to induce genetic instability/DNA damage. Review summarizes HPV involvement in all reproductive stages, evaluate the adverse role(s) played by HPVs, and identifies mechanisms of viral pathogenicity, common as well as specific for each stage of the reproduction process.

Exogenous Factors Affecting the Functional Integrity of Male Reproduction

Natural processes along with increased industrial production and the irresponsible behavior of mankind have resulted in environmental pollution. Environmental pollutants can be categorized based on their characteristics and appearance into the following groups: physical, biological, and chemical. Every single one of them represents a serious threat to the male reproductive tract despite the different modes of action. Male gonads and gametes are especially vulnerable to the effect of exogenous factors; therefore, they are considered a reliable indicator of environmental pollution. The impact of xenobiotics or radiation leads to an irreversible impairment of fertility displayed by histological changes, modulated androgen production, or compromised spermatozoa (or germ cells) quality. The present article reviews the exogenous threats, male reproductive system, the mode of action, and overall impact on the reproductive health of humans and animals.

Evaluation of human papilloma virus in semen as a risk factor for low sperm quality and poor in vitro fertilization outcomes: a systematic review and meta-analysis

OBJECTIVE

To analyze the effect of human papilloma virus (HPV) sperm infection on sperm parameters and in vitro fertilization (IVF) outcomes.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENTS

Men with HPV sperm infection and couples undergoing IVF.

INTERVENTIONS

Searches were conducted in the following databases: Medline(R), PubMed, Embase, Web of Science, Scopos, and the Cochrane Library. We included studies examining sperm parameters and IVF results in patients with and without HPV sperm infection.

MAIN OUTCOME MEASURES

Sperm analysis (concertation, count, volume, motility, morphology), according to the World Health Organization manual, pregnancy rate (PR), and miscarriage rate (MR).

RESULTS

Sixteen studies were included in this meta-analysis. The presence of HPV had a significant association with impaired sperm parameters in terms of concentration (mean difference [MD] -4.48, 95% confidence interval [CI] - 6.12 to -2.83), motility (MD -11.71, 95% CI - 16.15 to -7.26), and morphology (MD -2.44, 95% CI - 4.08 to -0.79. A review of the literature regarding ART outcomes showed an association between HPV infection and decreased PR, and an even stronger association between HPV infection and increased MR.

CONCLUSION

Our meta-analysis shows a negative effect of HPV on sperm concentration, motility, and morphology. Further subgroup and categorical analysis confirmed the clinical significance of impaired sperm motility in HPV-infected sperm, although the sperm count and morphology must be carefully analyzed. The studies reviewed reported lower PR and increased MR in couples with HPV-infected sperm. As most studies had a moderate risk of bias, these observations warrant further large, well-designed studies before introducing clinical management recommendations.

PROSPERO REGISTRATION NUMBER

CRD42019127419.

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.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.

High prevalence of urogenital infection/inflammation in patients with azoospermia does not impede surgical sperm retrieval

Considering infection/inflammation to be an important risk factor in male infertility, the aim of this study was to make a comprehensive evaluation of the prevalence of urogenital tract infection/inflammation and its potential impact on sperm retrieval in azoospermic patients. In this prospective study, 71 patients with azoospermia were subjected to an extensive andrological workup including comprehensive microbiological diagnostics (2-glass test, semen, testicular swab and testicular tissue analysis) and testicular biopsy/testicular sperm extraction (TESE). Medical history suggested urogenital tract infection/inflammation in 7% of patients, 11% harboured STIs, 14% showed significant bacteriospermia, 15% had seminal inflammation, 17% fulfilled the MAGI definition, and 27% had relevant pathogens. At the testicular level, 1 patient had a swab positive for bacteria, no viruses were detected, tissue specimens never indicated pathogens, whereas histopathology revealed focal immune cell infiltrates in 23% of samples. Testicular sperm retrieval rate was 100% in obstructive and 46% in nonobstructive azoospermia. None of the infection/inflammation-related variables was associated with the success of sperm retrieval or inflammatory lesions in the testis. The high prevalence of urogenital infection/inflammation among azoospermic men underpins their role as significant aetiologic factors in male infertility. However, this observation does not refer to the chances of sperm retrieval at the time of surgery/TESE.

Seminal human papillomavirus originates from the body surface and is not a frequent aetiological factor in azoospermia

Human papillomavirus (HPV) DNA has been detected in the testis tissue of 6.5% of 185 men with non‐obstructive azoospermia (NOA). Others have suggested that seminal HPV originates from contamination from the genital skin and mucosa. One hundred unselected azoospermic men and 43 normal men undergoing vasectomy were recruited. Testicular biopsies for HPV examination were collected from all the men. Additionally, the normal men undergoing vasectomy delivered a semen sample and had a swab for HPV examination taken from the genital skin before vasectomy. A piece of each Vas deferens obtained during the vasectomy was examined for the presence of HPV. Two of the primarily azoospermic men were shown to have cryptozoospermia. It was not possible to detect HPV in the testis tissue of any of the included 98 azoospermic men or the 43 proven fertile men. In the proven fertile men, HPV DNA was detected in the semen of 15 men (35%), on the genital skin of 28 men (65%), and in the Vas deferens in three cases (7%). In 13 (87%) men with HPV‐positive semen samples, HPV DNA was also detected in the skin swabs, and in 11 men (73%), identical HPV genotypes were found in the two locations.

[Infection and infertility]

BACKGROUND

Infections in the urogenital tract are accepted causes of male infertility. Epidemiologic data indicate 6-10 % of all males undergoing andrological work-up for infertility having an infectious etiology.

TOPICS

This review gives a comprehensive overview on the most important urogenital tract infections (prostatitis, epididymitis, orchitis, male accessory gland infection-MAGI) and the impact on fertility. In males suffering infertility, evidence is also presented regarding an infectious etiology.

Human papillomavirus (HPV) infection: a Mozambique overview

Human Papillomavirus is agent of the most common sexually transmitted disease which is able to infect mucosal and cutaneous membranes of the anogenital region, upper aerodigestive tract, and other head and neck mucosal regions. Although mainly HPV infection can be asymptomatic and transient, it may persist and give rise to various lesions such as warts, condyloma dysplasia and cancers depending on low or high risk type of HPV infection. Moreover, growing recent evidence suggests a role of this virus in male and female fertility. To date no effective prevention, test, treatment and control strategies are provided for people in developing countries despite the reported high incidence of HPV both in women and men. This paper reviews the more recent literature about HPV infection highlighting epidemiology, related pathologies and possible fertility effects of HPV in male and female with particular attention to the Mozambique context.

High HPV infection prevalence in men from infertile couples and lack of relationship between seminal HPV infection and sperm quality

Human papillomaviruses (HPV) are the most frequently sexually transmitted viruses and etiological agents of several human cancers. Controversial results of the role of HPV in infertile population on sperm parameters have been published. The aim of this study was to estimate the type-specific prevalence of HPV DNA infection of the external genitalia and semen in 340 Slovenian men from infertile couples and to establish the relationship between seminal HPV DNA infection and abnormal sperm parameters. Self-taken swabs of the entire penile surface and semen samples were collected, and HPV detection and genotyping were performed. HPV DNA was detected in 37.12% of external genitalia and in 13.61% of semen samples with high HPV type concordance of both sampling sites. The most prevalent HPV types in the male external genitalia were HPV-CP6108 and HPV-84. The most prevalent HPV types in semen were HPV-53 and HPV-CP6108. The prevalence of HPV infection between normozoospermic men and men with abnormal sperm parameters did not differ significantly. Sperm quality did not differ significantly between men with seminal HPV infection and uninfected men. In conclusion, the men from infertile couples are equally susceptible to HPV infection regardless of their fertile potential; seminal HPV infection does not impair sperm quality.

Detection of oncogenic human papillomavirus genotypes on spermatozoa from male partners of infertile couples

OBJECTIVE

To evaluate the prevalence of human papillomavirus (HPV) sperm infection and its correlation with sperm parameters in patients who attended a fertility clinic.

DESIGN

Cross-sectional clinical study.

SETTING

University-affiliated reproductive medicine clinic.

PATIENT(S)

A total of 308 male partners of couples undergoing in vitro fertilization techniques.

INTERVENTION(S)

Specimens of semen were collected from all patients.

MAIN OUTCOME MEASURE(S)

Sperm parameters were evaluated according to the World Health Organization manual. The presence of HPV DNA was researched by the combined use of two HPV assays and a highly sensitive nested polymerase chain reaction assay followed by HPV genotyping. To examine whether HPV was associated with the sperm, in situ hybridization (ISH) analysis was performed.

RESULT(S)

Results of HPV investigation were compared with sperm parameters and ISH analysis. Twenty-four out of 308 semen samples (7.8%) were HPV DNA positive, but HPV infection did not seem to affect semen quality. Moreover, ISH revealed a clear HPV localization at the equatorial region of sperm head in infected samples.

CONCLUSION(S)

Oncogenic HPV genotypes were detected on spermatozoa from asymptomatic subjects, but a role of the infection in male infertility was not demonstrated.

Lack of evidence for an association between seminoma and human papillomavirus infection using GP5+/GP6+ consensus primers

Testicular germ cell tumors account for about 1% of all cancers. The incidence of these tumors is increasing and they represent the most common solid malignancies of young men aged 15-40 years with seminoma being one of the most common histotype. Pathogenesis of testicular germ cell tumors remains unknown and, although cryptorchidism is considered the main risk factor, there is evidence of an association with environmental and genetic risk factors. Human papillomaviruses (HPV) are a family of DNA viruses and represent a major risk factor for cervical cancer. In addition, they have been associated with other human non-malignant and malignant diseases, including breast and head and neck cancer. HPV sequences have been detected throughout the male lower genitourinary tract as well as in seminal fluid and an increased testicular tumorigenesis has been reported in HPV transgenic mice. Aim of this study was to evaluate the potential involvement of HPV in human testicular tumorigenesis. Real-time PCR employing GP5+/GP6+ consensus HPV primers was used to examine the presence of HPV sequences in a subset of human seminoma (n = 61) and normal testicles (n = 23). None of the specimens tested displayed the presence of HPV DNA. These findings do not support an association between HPV and human seminoma and warrant further studies to assess definitively the role of these viruses in human testicular tumorigenesis.

Comparison of the prevalence and distribution of human papillomavirus infection and cervical lesions between urban and native habitants of an Amazonian region of Peru

We made a study of the prevalence of human papillomavirus (HPV) and cervix lesions in an Amazonian Bora native population (Bn) and compared it with the prevalence in an urban population in Iquitos (Iq). We also examined the distribution of HPV types among abnormal cervical smears in the Iq population. Swabs and cytologies were collected from 472 females. DNA consensus PCR, followed by direct sequencing, were used to determinate the HPV types in the swabs. Cytologies were classified based on the lesion grade. HPV prevalence was 43.9% in Iq and 35.4% in Bn. Cervix lesion prevalence was 20.0% in Iq and 0.3% in Bn. The frequency of high-risk HPV types among HPV+ females was 71.9% in Iq and 56.3% in Bn. The frequencies of low-risk and undetermined risk HPV types were 19.3/6.3% (Iq/ Bn) and 12.3/37.5% (Iq/Bn), respectively. In lesIq (women seeking cytological services with a previous cervix lesion diagnosis) the prevalence of HPV, was 72.9%. The incidence of carcinoma and high-grade squamous intraepithelial cervix lesions in lesIq were 31.2 and 18.8%, respectively. The Bn population had a lower incidence of high-risk HPV and cervix lesions. The high-risk strain HPV16 was significantly more frequent in Iq compared with Bn. lesIq high-risk HPVs were more frequent in high-grade squamous intraepithelial lesions and carcinoma. High-risk HPV16 prevalence was significantly higher than the prevalence of the other high-risk HPVs, especially in the high-grade squamous intraepithelial lesions and carcinoma.

Barriers of the Human Organism and Their Achilles’ Heels

The human body is covered by barriers separating it from the external and internal surroundings. The “milieu enterieur” has to be stabilised in spite of the variable external and internal conditions of toxic, osmotic, microbial and climatic environmental circumstances. This first line of barriers is composed of skin and mucous membranes of complicated structures.

A second line of barrier system is present in our organisms. Certain organs have to be separated from the immune system and other parts of the body because of evolutionary reasons (eye-bulb and testicles) because of unique proteins “unknown” for the acquired immune system. The blood-brain barrier (BBB) is providing enhanced safety circumstances for the central nervous system. The second line of barriers is represented by the special properties of the capillary endothelial system.

The maternal-fetal barrier is the most complex. At the maternal fetal interface two individuals of two different haplotypes has to be live 9 months separated by a very complicated dynamic barrier.

The placenta is the organ, which is separating the maternal and fetal tissues. Similar to others the bidirectional transport of gasses, metabolites, cells, proteins, regulatory substances, are transported by active or passive transcellular and intercellular mechanisms.

The fetal immune system develops immunotolerance to all maternal cells and antigens transferred transplacentally. The problem is to mitigate the maternal immune system to tolerate the paternal haplotype of the fetus. In the case of normal pregnancy a complex series of physiological modifications can solve the problem without harmful consequences to the mother and fetus.

The outermost contact cells of trophoblasts express instead of HLA-class Ia and class II antigens non-variable HLA-C, HLA-E, HLA-F and HLA-G antigens. The first consequence of this is reduction of the activity of maternal natural killer cells and maternal dendritic cells;

Progesteron, micro-RNA and mediators influence the development of T effector-cells. The production of soluble HLA-G(5 and 6) and IL-10 supports the differentiation of Th-2 CD4⁺ helper cells, reducing the ability of maternal cells to kill fetal cells.

Series of receptors and costimulators are expressed by the different lines of semi-allogenic trophoblast cells to bind HLA-G and mitigate maternal immune response;

The maternal immunotolerance is further facilitated by the activation of CD4⁺CD25^brightFoxp3⁺ regulatory T (T_REG) cells.

Infections have to be prevented during pregnancy. The cells of placenta express 10 Toll-like receptors a group of pattern recognition receptors responsible for innate immunity. The interferon level is also higher in the placental tissues than in the somatic fetal or maternal cells.

The complement system is also adapted to the requirements of the pregnancy and fetal damage is inhibited by the production of “assymmetric IgG antibodies” under hormonal and placental-regulation. These modifications prevent the activation of complement, cytotoxic activity, opsonising ability, antigen clearance and precipitating activity of the molecules.

The Achilles’ heels of the different barriers are regularly found by virus infections. Lamina cribrosa of the blood-brain barrier, optical nerve of the eyes, etc. the risk factors of the maternal-fetal barrier has been summarised in Table 1.1.

Mechanism of human papillomavirus binding to human spermatozoa and fertilizing ability of infected spermatozoa

Human papillomaviruses (HPVs) are agents of the most common sexually transmitted diseases in females and males. Precise data about the presence, mechanism of infection and clinical significance of HPV in the male reproductive tract and especially in sperm are not available. Here we show that HPV can infect human sperm, it localizes at the equatorial region of sperm head through interaction between the HPV capsid protein L1 and syndecan-1. Sperm transfected with HPV E6/E7 genes and sperm exposed to HPV L1 capsid protein are capable to penetrate the oocyte and transfer the virus into oocytes, in which viral genes are then activated and transcribed. These data show that sperm might function as vectors for HPV transfer into the oocytes, and open new perspectives on the role of HPV infection in males and are particularly intriguing in relation to assisted reproduction techniques.

Prevalence and distribution of human papillomavirus findings in swab specimens from gynaecology clinics of the east coast of Spain

The objective of this study was to determine the prevalence of human papillomavirus (HPV) among females in the east coast of Spain. A total of 1956 women visiting gynaecology clinics for routine check-ups were included in the study. Swabs were analyzed for HPV DNA by consensus polymerase chain reaction followed by direct sequencing. The overall HPV prevalence was 12.99%. HPV vaccine types 6, 11, 16 and 18 were detected in 6.13% of female participants.