Mumps orchitis in the non-immune postpubertal male: a resurgent threat to male fertility?

[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.

Mevalonate pathway and male reproductive aging

Male fertility declines with age. The mevalonate pathway, through which cholesterol and nonsteroidal isoprenoids are synthesized, plays key role in metabolic processes and is an essential pathway for cholesterol production and protein prenylation. Male reproductive aging is accompanied by dramatic changes in the metabolic microenvironment of the testis. Since the mevalonate pathway has an important role in spermatogenesis, we attempted to explore the association between male reproductive aging and the mevalonate pathway to explain the mechanism of male reproductive aging. Alterations in the mevalonate pathway may affect male reproductive aging by decreasing cholesterol synthesis and altering testis protein prenylation. Decreased cholesterol levels affect cholesterol modification, testosterone production, and remodeling of germ cell membranes. Aging-related metabolic disorders also affect the metabolic coupling between somatic cells and spermatogenic cells, leading to male fertility decline. Therefore, we hypothesized that alterations in the mevalonate pathway represent one of the metabolic causes of reproductive aging.

Severe Acute Respiratory Syndrome Coronavirus 2 and Male Reproduction: Relationship, Explanations, and Clinical Remedies

Coronavirus disease 2019 (COVID-2019) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been an ongoing pandemic and worldwide public health emergency, having drawn a lot of attention around the world. The pathogenesis of COVID-19 is characterized by infecting angiotensin-converting enzyme 2 (ACE2)-expressing cells, including testis-specific cells, namely, Leydig, Sertoli, and spermatogenic cells, which are closely related to male reproduction. This leads to aberrant hyperactivation of the immune system generating damage to the infected organs. An impairment in testicular function through uncontrolled immune responses alerts more attention to male infertility. Meanwhile, the recent clinical data indicate that the infection of the human testis with SARS-CoV-2 may impair male germ cell development, leading to germ cell loss and higher immune cell infiltration. In this review, we investigated the evidence of male reproductive dysfunction associated with the infection with SARS-CoV-2 and its possible immunological explanations and clinical remedies.

Immunologic Environment of the Testis

Mammalian spermatogenesis is a carefully orchestrated male germ cell differentiation process by which spermatogonia differentiate to spermatozoa in the testis. A highly organized testicular microenvironment is therefore necessary to support spermatogenesis. Regarding immunologic aspects, the testis adapts a specialized immune environment for the protection of male germ cells and testicular functions. The mammalian testis possesses two immunologic features: (1) it is an immunoprivileged organ where immunogenic germ cells do not induce deleterious immune responses under physiologic conditions; and (2) it creates its own effective innate defense system against microbial infection. Various pathologic conditions may disrupt testicular immune homeostasis, thereby resulting in a detrimental immune response and perturbing testicular functions, one of the etiologic factors of male infertility. Understanding the mechanisms underlying immunoregulation in the testis can aid in establishing strategies for the prevention and therapy of immunologic testicular dysfunction and male infertility. This chapter focuses on the mechanisms underlying immune privilege, local innate immunity, and immunologic diseases of the testis.

Roles of Sialic Acid, AXL, and MER Receptor Tyrosine Kinases in Mumps Virus Infection of Mouse Sertoli and Leydig Cells

The mumps virus (MuV) causes epidemic parotitis. MuV also frequently infects the testis and induces orchitis, an important etiological factor contributing to male infertility. However, mechanisms underlying MuV infection of the testis remain unknown. Here, we describe that sialic acid, AXL, and MER receptor tyrosine kinases regulate MuV entry and replication in mouse major testicular cells, including Sertoli and Leydig cells. Sialic acid, AXL, and MER were present in Sertoli and Leydig cells. Sialic acid specifically mediated MuV entry into Sertoli and Leydig cells, whereas both AXL and MER facilitated MuV replication within cells through the inhibition of cellular innate antiviral responses. Mechanistically, the inhibition of type 1 interferon signaling by AXL and MER is essential for MuV replication in Sertoli and Leydig cells. Our findings provide novel insights into the mechanisms behind MuV infection and replication in the testis.

SARS-CoV-2: diagnostic and design conundrums in the context of male factor infertility

The question of whether SARS-CoV-2 (severe acute respiratory syndrome-related coronavirus-2 [SARS-CoV-2], leading to the COVID-19 infection) can be harboured in the testes and/or semen is currently unanswered. It is essential to understand the limitations of both antibody and real-time PCR tests in interpreting SARS-CoV-2 data in relation to analyses of semen and testicular tissue without appropriate controls. This article critically analyses the evidence so far on this, and the possible implications. The limitations of diagnostic tests in both sampling and testing methodologies, their validation and their relevance in interpreting data are also highlighted.

Mumps virus infection disrupts blood-testis barrier through the induction of TNF-α in Sertoli cells

Mumps virus (MuV) has high tropism to the testis and may lead to male infertility. Sertoli cells are the major targets of MuV infection. However, the mechanisms by which MuV infection impairs male fertility and Sertoli cell function remain unclear. The present study elucidated the effect of MuV infection on the blood-testis barrier (BTB). The transepithelial electrical resistance of MuV-infected mouse Sertoli cells was monitored, and the expression of major proteins of the BTB was examined. We demonstrated that MuV infection disrupted the BTB by reducing the levels of occludin and zonula occludens 1. Sertoli cells derived from Tlr2^-/- and Tnfa^-/- mice were analyzed for mediating MuV-induced impairment. TLR2-mediated TNF-α production by Sertoli cells in response to MuV infection impaired BTB integrity. MuV-impaired BTB was not observed in Tlr2^-/- and Tnfa^-/- Sertoli cells. Moreover, an inhibitor of TNF-α, pomalidomide, prevents the disruption of BTB in response to MuV infection. FITC-labeled biotin tracing assay confirmed that BTB permeability and spermatogenesis were transiently impaired by MuV infection in vivo. These findings suggest that the disruption of the BTB could be one of the mechanisms underlying MuV-impaired male fertility, in which TNF-α could play a critical role.-Wu, H., Jiang, X., Gao, Y., Liu, W., Wang, F., Gong, M., Chen, R., Yu, X., Zhang, W., Gao, B., Song, C., Han, D. Mumps virus infection disrupts blood-testis barrier through the induction of TNF-α in Sertoli cells.

Zoledronic acid induces cytogenetic toxicity in male germline cells of Swiss albino mice

This study mainly focuses on the cytogenetic toxicity induction by zoledronic acid (ZA), a nitrogen containing bisphosphonate (N-BPs) in the male germline cells of Swiss albino mice. A single intraperitoneal exposure with three different doses of ZA (2, 4, and 8 mg/kg body weight), toxicity was assessed by analyzing spermatogonial metaphase chromosome aberrations at 24 h, aberrant primary spermatocytes at week 4, and abnormal spermatozoa at week 8 posttreatment. Cyclophosphamide (40 mg/kg) and 0.9% NaCl were used as positive and vehicle controls respectively in the study. The results showed that there was a significant induction in the number of chromosomal aberrations especially at two doses of ZA (4 and 8 mg/kg) after 24 h in the spermatogonial cells (p < 0.001) compared to vehicle control. The transmission genetic damages were noticed as aberrant spermatocytes with atypical bivalents (X-Y/autosomal asynapsis) at 4 mg/kg of ZA (p < 0.01) and at 8 mg/kg of ZA (p < 0.001) at week 4 posttreatment. A statistically significant higher number of abnormal spermatozoa (sperm) were also noticed at week 8 posttreatment of both at 4 and 8 mg/kg of ZA (p < 0.001). Hence, from these genotoxicity studies, it can be concluded that ZA is genotoxic in male germline cells and has the potential of transmitting the genotoxic effects from spermatogonial cells to sperm in male Swiss mice.

Mumps Orchitis

Although the incidence of mumps orchitis has dramatically declined since the introduction of the childhood vaccination programme, a sharp increase in reported cases of both mumps and mumps orchitis has been seen recently in the UK. There are great concerns about mumps outbreaks and the associated risk of infertility; it remains an important clinical condition. Immunization is the best policy to avoid this viral disease.

Hypogonadism in the HIV-Infected Man

Low testosterone levels are frequently observed among men with treated and untreated HIV infection. However, the interpretations of biochemical measurements of testicular function are challenging and need to be considered in the context of the clinical presentation and scenario. The distinction between primary and secondary hypogonadism and determination of the underlying clinical pathophysiology are not always straightforward. Early recognition of clinical hypogonadism and appropriate treatment may improve clinical outcomes and quality of life for affected individuals. A principal aim of testosterone replacement is to maintain serum testosterone concentrations in the normal physiological range and should be considered in clinically symptomatic patients.

Mouse Testicular Cell Type-Specific Antiviral Response against Mumps Virus Replication

Mumps virus (MuV) infection has high tropism to the testis and usually leads to orchitis, an etiological factor in male infertility. However, MuV replication in testicular cells and the cellular antiviral responses against MuV are not fully understood. The present study showed that MuV infected the majority of testicular cells, including Leydig cells (LC), testicular macrophages, Sertoli cells (SC), and male germ cells (GC). MuV was replicated at relatively high efficiencies in SC compared with LC and testicular macrophages. In contrast, MuV did not replicate in male GC. Notably, testicular cells exhibited different innate antiviral responses against MuV replication. We showed that interferon β (IFN-β) inhibited MuV replication in LC, macrophages, and SC, which were associated with the upregulation of major antiviral proteins. We provided primary evidence that autophagy plays a role in blocking MuV replication in male GC. Autophagy was also involved in limiting MuV replication in testicular macrophages but not in Leydig and SC. These findings indicate the involvement of the innate defense against MuV replication in testicular cells.

Estimating true hospital morbidity of complications associated with mumps outbreak, England, 2004/05

Mumps outbreaks in highly vaccinated populations continue to be reported globally. Therefore, quantifying the burden of mumps morbidity accurately will be necessary to better assess the impact of mumps vaccination programmes. We aim to estimate the true morbidity resulting from mumps complications in terms of hospitalised orchitis, meningitis, oophoritis and pancreatitis in England during the outbreak in 2004/05. This outbreak in England led to a clear increase in hospitalisations coded to mumps for complications of orchitis in those born in the 1970s and 1980s and possibly for meningitis in those born in the 1980s. A simple statistical model, based on analysing time trends for diagnosed complications in hospital databases with routine laboratory surveillance data, found that the actual morbidity was much higher. There were 2.5 times (166 cases) more mumps orchitis cases in the 1970s cohort and 2.0 times (708 cases) more mumps orchitis cases in the 1980s cohort than complications coded to mumps in hospital databases. Our study demonstrated that the mumps outbreak in England 2004/05 resulted in a substantial increase in hospitalised mumps complications, and the model we used can improve the ascertainment of morbidity from a mumps outbreak.

Mumps virus-induced innate immune responses in mouse Sertoli and Leydig cells

Mumps virus (MuV) infection frequently causes orchitis and impairs male fertility. However, the mechanisms underlying the innate immune responses to MuV infection in the testis have yet to be investigated. This study showed that MuV induced innate immune responses in mouse Sertoli and Leydig cells through TLR2 and retinoic acid-inducible gene I (RIG-I) signaling, which result in the production of proinflammatory cytokines and chemokines, including TNF-α, IL-6, MCP-1, CXCL10, and type 1 interferons (IFN-α and IFN-β). By contrast, MuV did not induce the cytokine production in male germ cells. In response to MuV infection, Sertoli cells produced higher levels of proinflammatory cytokines and chemokines but lower levels of type 1 IFNs than Leydig cells did. The MuV-induced cytokine production by Sertoli and Leydig cells was significantly reduced by the knockout of TLR2 or the knockdown of RIG-I signaling. The local injection of MuV into the testis triggered the testicular innate immune responses in vivo. Moreover, MuV infection suppressed testosterone synthesis by Leydig cells. This is the first study examining the innate immune responses to MuV infection in testicular cells. The results provide novel insights into the mechanisms underlying the MuV-induced innate immune responses in the testis.

Infectious, inflammatory, and immunologic conditions resulting in male infertility

This article provides an overview of infectious and inflammatory conditions associated with male infertility. These conditions may affect several components of the male reproductive tract and therefore have the ability to potentially alter sperm function. The effect of these conditions on male fertility is poorly understood and often underestimated.

Clinical features of mumps orchitis in vaccinated postpubertal males: a single-center series of 62 patients

Purpose

Although the measles-mumps-rubella vaccination covers most children against mumps in Korea, the development of mumps has been reported. However, the clinical manifestations of mumps orchitis in postpubertal vaccinated patients have never been investigated. Herein we report the clinical features of mumps orchitis in postpubertal vaccinated patients.

Materials and Methods

This study included a total of 62 postpubertal males who developed acute mumps orchitis from 2005 to 2010. The clinical manifestations such as the incubation period, febrile duration, and the mean duration of orchitis were retrospectively investigated. The laboratory and sonographic findings were also reviewed and compared with the features of previously reported cases of unvaccinated postpubertal mumps orchitis.

Results

The mean age of the 62 patients was 17.56 years (range, 15 to 29 years). All patients were serologically confirmed with acute mumps infection (positive immunoglobulin [Ig] M and negative or positive IgG). The mean incubation period was 5.39 days (range, 0 to 23 days), with a febrile duration of 1.8 days (range, 0.5 to 3 days), and a mean duration of orchitis of 4.96 days (range, 0 to 17 days). Sonography revealed unilateral orchitis in 58 patients (93.6%) and bilateral orchitis in only 6 (6.4%).

Conclusions

In our study, mumps orchitis in postpubertal vaccinated patients showed a relatively shorter febrile duration. In addition, less scrotal swelling and a lower incidence of bilaterality were found upon physical examination and ultrasonography. In the future, additional long-term follow-up is needed to determine the features of mumps orchitis in postpubertal vaccinated males, and an additional booster vaccination should be considered.

[Orchitis and male infertility]

Infections and inflammations of the genital tract are considered the most frequent causes of reduced male fertility, but conclusive epidemiological data are not available. In view of the exposure of germ cells to pathogenic components as well as the cells and mediators involved in the inflammatory processes, irreversible damage to spermatogenesis and corresponding decline of ejaculate quality are to be expected, particularly in cases of chronic orchitis. While the consequences of orchitis and epididymo-orchitis that exhibit clinical symptoms due to systemic or local infections are well known, including testicular atrophy and complete loss of fertility, those cases of inflammatory reactions of the testicles that manifest an asymptomatic or subclinical course, or are not even due to an infection, have received little attention until now. However, systematic histopathological analyses have shown a high prevalence of asymptomatic inflammatory reactions in testicular biopsies from infertile men. The mostly focal lymphocytic infiltrates correlate with the degree of damage to spermatogenesis and corresponding clinical and endocrinological parameters of testicular function. Noninvasive diagnostic techniques are not yet available so that chronic asymptomatic inflammations of the testicles as the primary cause or cofactor of male fertility disorders are underestimated. Except for administration of pathogen-specific antibiotics, treatment recommendations are to a large extent still lacking.

Long-term efficacy and safety of interferon-alpha-2B in patients with mumps orchitis

The aim of this study was to determine long-term efficacy and safety subcutaneous injection of interferon-alpha-2B in patients with mumps orchitis in terms of testicular volume and other testicular functions. Mumps orchitis was evaluated in 37 patients. Patients were hospitalized and administered 1 × 3,000,000 IU subcutaneous injection of interferon-alpha-2B daily for 7 days. The testicular volumes of all the patients were measured by ultrasonography in the 18th month following treatment termination. The testes volumes were evaluated by descriptive statistics as percentages. Patients were divided into three groups according to testes volumes and differences between the involved and non-involved testicles. Group I included patients with normal testes volume (> 12 ml) and a difference between testes of less than 2 ml or 20%; Group II (atrophic groups) included patients with testes volume of less than 12 ml; and Group III (hypotrophic groups) included patients with testes volume of greater than 12 ml and a difference between testes of more than 2 ml or 20%. Groups were compared in terms of results of semen analysis and serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels. Patients' ages ranged between 17 and 41 years (mean: 28.3 years). A total of nine atrophy cases were identified. Sixteen patients were determined to have hypotrophic testes with a difference of 2-10 ml or 20% between the involved and non-involved testicles, despite the absence of testicular atrophy. A comparison of groups revealed that sperm density, total sperm count, total motile sperm count, and motility percentage were significantly higher in Group I than in the other groups, while serum FSH and LH levels were lower in Group I than in the other groups. Although the use of interferon-alpha-2B appears to prevent testicular atrophy and protect testicular function, it leads to a considerable difference in the volume between testicles and a significant loss of testicular function. As a result, further studies are required in order to investigate the efficacy of the drug.

Mumps orchitis in the post-vaccine era (1967-2009): a single-center series of 67 patients and review of clinical outcome and trends

Since the introduction of the mumps vaccine, the age of appearance of mumps infection has shifted from children to adolescents and young adults, groups with a higher incidence of disease complications and sequelae. During the years 2000-2001, the Gran Canaria Island was part of an epidemic of mumps. In that period, our institution attended 67 cases of serologically confirmed acute mumps orchitis, the most serious complication of mumps infection in young postpubertal males. We conducted a descriptive and prospective study of this cohort and extensively reviewed the literature from 1967 (the year the first mumps vaccine was introduced) to 2009. Fifty-six patients were admitted because of general impairment and were treated with alpha-interferon. Sixty-six patients presented parotitis previous to orchitis (interval from parotitis to orchitis, 4.9 d). Orchitis was unilateral in 89.5% and bilateral in 10.4% of cases. More than 98% of patients had orchitis-associated fever. Nine patients had clinical and biochemical data showing acute mumps meningitis, and 11 had subclinical pancreatitis. The mean duration of symptoms was 4.6 days (range, 1-9). During the acute phase, more than 41% of the evaluated testes had a volume >25 mL. Acute hormonal disturbances were highly prevalent. These included decreased levels of testosterone and inhibin B with low or normal levels of gonadotropins in 35% of subjects, and, to our knowledge not previously reported, an atypical hormonal pattern consisting of low levels of free testosterone and inhibin B, along with increased measures of luteinizing hormone but low or normal follicle-stimulating hormone levels (11% of cases). During the follow-up period (mean, 331 d) a high incidence of sperm disturbance was found.

The increasing incidence of mumps orchitis: a comprehensive review

There has been a recent increase in mumps orchitis among pubertal and postpubertal males. These outbreaks can be attributed to a reduction in the uptake of measles-mumps-rubella (MMR) vaccine during the early to mid-1990 s in children who have now matured. The mumps virus is commonly associated with extra-salivary complications. Unvaccinated postpubertal males diagnosed with mumps virus frequently develop complications such as mumps orchitis. Therefore, it is important that urologists are familiar with the diagnosis, treatment and complications of this condition. Here we review the epidemiology, clinical presentation, diagnostic methods, treatment options and complications of mumps orchitis, as a complication of mumps virus, with particular emphasis on testicular atrophy, subfertility and infertility.

Testicular Torsion: Twists and Turns

Testicular torsion is one of the common causes of acute scrotal pain. This review discusses the clinical and sonographic findings of intravaginal and extravaginal testicular torsion, including the normal sonographic and vascular anatomy of the testis. The role of color flow Doppler and spectral Doppler is also emphasized in the patient's complete, incomplete, and intermittent testicular torsion. Sonographic features of testicular torsion mimics, such as vasculitis, venous thrombosis, scrotal edema, and technical parameters, are also presented. A brief description of new developments such as contrast-enhanced ultrasound, dynamic contrast magnetic resonance imaging, and near-infrared imaging is included.

Mumps orchitis

Although the incidence of mumps orchitis has dramatically declined since the introduction of the childhood vaccination programme, a sharp increase in reported cases of both mumps and mumps orchitis has been seen recently in the UK. There are great concerns about mumps outbreaks and the associated risk of infertility; it remains an important clinical condition. Immunization is the best policy to avoid this viral disease.