Detection of human herpesviruses (HHVs) in semen of human male infertile patients

[Infections and male infertility]

BACKGROUND

The role of urogenital infections in male infertility has long been the subject of debate.

METHODS

A bibliographic search limited to English-language literature on human subjects published before 5/2023 resulted in the selection of 189 articles.

RESULTS

Male infertility is often of multifactorial aetiology, and to optimise the prognosis it is important to manage all the factors that can be corrected, including infectious causes, which represent one of the most frequent aetiologies. The infectious agents involved in urogenital infections are most often bacterial or viral, and more rarely parasitic. They can infect the seminal tract, male accessory glands and/or testicles, and usually result in inflammation and increased oxidative stress. These infections reduce male fertility, in particular by altering spermogram parameters and increasing sperm DNA fragmentation. For these reasons, the search for a urogenital infection should be systematic, involving a careful history and clinical examination, ultrasound and systematic bacteriological tests guided by clinical findings. Aetiological treatment may be proposed depending on the picture and the germ involved.

CONCLUSION

This review should help the urologist to establish an accurate diagnosis of the form and extent of the infection, and enable him to define an appropriate therapeutic strategy, tailored to the patient, in order to obtain the best chances of improving male fertility.

Circulatory exosomal tRF-Glu-CTC-005 and tRF-Gly-GCC-002 serve as predictive factors of successful microdissection testicular sperm extraction in patients with nonobstructive azoospermia

OBJECTIVE

To identify circulating plasma exosomal transfer RNA-derived fragments (tRFs) as the predictive factors of successful microdissection testicular sperm extraction (micro-TESE) in patients with nonobstructive azoospermia (NOA).

DESIGN

Case and control prospective study.

SETTING

Academic research laboratory.

PATIENT(S)

Twelve patients with NOA with successful sperm retrieval by micro-TESE, 18 patients with NOA with failed sperm retrieval by micro-TESE, and 12 normozoospermic fertile controls.

INTERVENTION(S)

Blood samples were collected from participants.

MAIN OUTCOME MEASURE(S)

The abundance of tRFs normalized as counts per million of the total aligned reads with the next-generation sequencing system; candidate tRF levels were validated through quantitative reverse transcription polymerase chain reaction; predictive accuracy was evaluated by the receiver operating characteristic area under the curve analysis. The nomogram was built for ranking.

RESULT(S)

The plasma circulating exosomal tRF-Gly-GCC-002 and tRF-Glu-CTC-005 manifested the most confident differential expression between patients with NOA with successful sperm retrieval by micro-TESE and patients with NOA with failed sperm retrieval by micro-TESE. The target gene prediction of these 2 tRFs followed by the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicated the functional enrichment of neuroendocrine protein metabolism and striatum/subpallium development. The herpes simplex virus 1 infection pathway was also involved. The receiver operating characteristic area under the curve (AUC) analysis demonstrated a promising predictive accuracy: tRF-Gly-GCC-002, AUC of 0.921, and tRF-Glu-CTC-005, AUC of 0.954. A regression model was built and presented with the nomogram for further assessment.

CONCLUSION(S)

This study described the exosomal tRF-Gly-GCC-002 and tRF-Glu-CTC-005 expression values, indicated a promising predictive effect for accessibility of sperm retrieval through micro-TESE from patients with NOA, and highlighted tRF-Gly-GCC-002 and tRF-Glu-CTC-005 as useful biomarkers in patients with NOA seeking in vitro conception with their residual sperm.

Viruses in the reproductive tract: On their way to the germ line?

Studies of vertebrate genomes have indicated that all species contain in their chromosomes stretches of DNA with sequence similarity to viral genomes. How such 'endogenous' viral elements (EVEs) ended up in host genomes is usually explained in general terms such as 'they entered the germ line at some point during evolution'. This seems a correct statement, but is also rather imprecise. The vast number of endogenous viral sequences suggest that common routes to the 'germ line' may exist, as relying on chance alone may not easily explain the abundance of EVEs in modern mammalian genomes. An increasing number of virus types have been detected in human semen and a growing number of studies have reported on viral infections that cause male infertility or subfertility and on viral infections that threaten in vitro fertilisation practices. Thus, it is timely to survey the pathway(s) that viruses can use to gain access to the human germ line. Embryo transfer and semen quality studies in livestock form another source of relevant information because virus infection during reproduction is clearly unwanted, as is the case for the human situation. In this review, studies on viruses in the male and female reproductive tract and in the early embryo will be discussed to propose a plausible viral route to the mammalian germ line.

What human sperm RNA-Seq tells us about the microbiome

PURPOSE

The study was designed to assess the capacity of human sperm RNA-seq data to gauge the diversity of the associated microbiome within the ejaculate.

METHODS

Semen samples were collected, and semen parameters evaluated at time of collection. Sperm RNA was isolated and subjected to RNA-seq. Microbial composition was determined by aligning sequencing reads not mapped to the human genome to the NCBI RefSeq bacterial, viral and archaeal genomes following RNA-Seq. Analysis of microbial assignments utilized phyloseq and vegan.

RESULTS

Microbial composition within each sample was characterized as a function of microbial associated RNAs. Bacteria known to be associated with the male reproductive tract were present at similar levels in all samples representing 11 genera from four phyla with one exception, an outlier. Shannon diversity index (p < 0.001) and beta diversity (unweighted UniFrac distances, p = 9.99e-4; beta dispersion, p = 0.006) indicated the outlier was significantly different from all other samples. The outlier sample exhibited a dramatic increase in Streptococcus. Multiple testing indicated two operational taxonomic units, S. agalactiae and S. dysgalactiae (p = 0.009), were present.

CONCLUSION

These results provide a first look at the microbiome as a component of human sperm RNA sequencing that has sufficient sensitivity to identify contamination or potential pathogenic bacterial colonization at least among the known contributors.

[Sexually transmitted infections and male fertility]

BACKGROUND

Sexually transmitted infections (STI) are common worldwide and can cause impairment of fertility. In women pelvic inflammatory disease with subsequent tubal sterility is well-documented but the influence of STI on male fertility is still controversely discussed OBJECTIVE: The effects of various bacterial and viral STI on male fertility are discussed.

MATERIAL AND METHODS

An evaluation of the international literature up to 30 April 2018 was carried out including studies on larger collectives from the Asiatic region.

RESULTS

There is still an inconsistent picture of the influence of various bacterial and viral STI on male fertility. Direct or indirect evidence of the impact of a pathogen alone on the quality of ejaculates could not be clearly demonstrated; however, there are indications of a negative effect by Mycoplasma and Ureaplasma species in large Asiatic collectives. The transmission of viral pathogens, such as human papillomavirus (HPV), herpes simplex virus (HSV) and hepatitis B virus (HBV) possible impairs the success of assisted reproductive techniques. In contrast, manifest inflammatory processes of the male genital tract caused by STI (in particular Chlamydia and gonococci) or human immunodeficiency virus (HIV) infections often result in impairment of sperm qualtity.

CONCLUSION

In cases of male fertility disorders a microbiological clarification is recommended. Further studies on the effect of STI on male fertility in larger collectives are necessary, particularly for Caucasian populations. The utilization of existing preventive measures, such as screening for Chlamydia in young women and HPV vaccination also for young males, should be intensively promoted.

Presence of human herpes virus 1-thymidine kinase in testis of azoospermic infertile herpes-infected patients

Infection with human herpes virus 1 (HHV1) is a suspected cause of human male infertility. However, the correlation between HHV1 infection and infertility is still unclear. We have previously generated transgenic rats that ectopically express the HHV1 thymidine kinase gene (HHV1-TK) in post-meiotic spermatids and found they had aberrant spermatogenesis and infertility. Therefore, we hypothesized that human infertility might be caused by HHV1 infection. Here, we examined whether HHV1-TK is expressed in human testis by analyzing the presence of its transcript and protein. Specimens were collected by biopsy from 30 azoospermic infertile male patients. RT-PCR and immunohistochemistry showed that 23 patients were positive for HHV1-TK expression, while seven patients were negative. Thus, we demonstrated HHV1-TK expression, indicating HHV1 infection, in the testis of human azoospermic infertile males for the first time; our findings represent a great advancement toward the verification of our hypothesis that HHV1-TK expression might cause human infertility.

Molecular detection of HHV1-5, AAV and HPV in semen specimens and their impact on male fertility

Viral infections have been considered as possible destructive factors that influence male fertility. The aim of this study was to determine the prevalence of human herpes viruses 1-5 (HHV1-5), adeno associated virus (AAV) and human papilloma virus (HPV) in semen and whether these influence semen quality. DNA extraction was performed using phenol-chloroform protocol, then three different nested-PCRs were done to detect HHV1-5, AAV and HPV DNAs in the semen samples. Of 145 samples, 66 (45.5%) were positive at least for one of the viruses. The genome detection rate of HSV1/2, VZV, EBV, HCMV, AAV and HPV were zero, 2.8%, zero, 1.4%, 27.6% and 19.3%, respectively. Of 66 positive samples for these viruses, 6 (4.1% of all samples) were positive for two viruses simultaneously. Here no association was found between variations in semen parameters related to fertility and detection of VZV, HCMV, AAV and HPV DNA in semen samples. It should be noted that the prevalence of different viruses in semen, and their relevance to male infertility, differs significantly due to the genome extraction and amplification methods or due to a real variation between study populations and geographical regions.

Cytokine expression profile in hospitalized children with herpes simplex virus-1 infection

Aim: We aim to demonstrate the cytokine expression profile of children with herpes simplex virus-1 (HSV-1) infection. Methods: One hundred eighty three children with acute encephalitis were enrolled in this study. Out of those with HSV-1, multiple cytokines were measured. Results: Cytokine analysis of 13 HSV-1-infected patients revealed that IL-8 and granulocyte macrophage colony stimulating factor accumulated at significantly higher levels than macrophage inflammatory protein-1β in the cerebrospinal fluid. Additionally, IFN-γ in serum and cerebrospinal fluid was positively correlated with course of illness, while IL-10 in cerebrospinal fluid was negatively correlated with course of illness. Conclusion: Granulocyte macrophage colony stimulating factor, IL-8, macrophage inflammatory protein-1β, IFN-γ and IL-10 are involved in the HSV-1 immune response and pathogenesis.

[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.

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.