Varicocele management in the era of in vitro fertilization/intracytoplasmic sperm injection

Seminal Calbindin 2 in Infertile Men With Varicocele: A Prospective Comparative Study

The present study compared seminal calbindin 2 (CALB 2) levels and semen parameters in men with and without varicocele. CALB 2 is also known as calretinin and 29 kDa calbindin. The study was a case-control study conducted from April (2021) to March (2022) in the andrology department at Beni-Suef University hospital. The study included four matched groups: group (I) were controls (fertile normozoospermic men without varicocele) (n=24). Group (II) were fertile normozoospermic men with varicocele (n=24). Group (III) were infertile oligoasthenoteratozoospermia (OAT) men without varicocele (n=24). Group (IV) were infertile OAT men with varicocele (n=24). The lowest levels of seminal CALB 2 were found in patients with severe oligozoospermia which showed a statistically significant difference when compared to seminal CALB 2 in patients with normal, mildly low, or moderately low sperm counts. There were significant negative correlations between sperm concentration, sperm motility and percentage of normal sperm forms and seminal CALB 2. Seminal plasma CALB 2 may play a role in the negative impact of varicocele on the semen parameters especially sperm concentration, sperm motility and percentage of sperm normal forms. Future studies are needed to verify these findings.

A Narrative Review Discussing Vasectomy-Related Impact upon the Status of Oxidative Stress and Inflammation Biomarkers and Semen Microbiota

Background: Male contraceptive approaches besides tubal sterilization involve vasectomy and represent the method of choice among midlife men in developing countries thanks to many advantages. However, the subsidiary consequences of this intervention are insufficiently explored since the involved mechanisms may offer insight into a much more complex picture. Methods: Thus, in this manuscript, we aimed to reunite all available data by searching three separate academic database(s) (PubMed, Web of Knowledge, and Scopus) published in the past two decades by covering the interval 2000–2023 and using a predefined set of keywords and strings involving “oxidative stress” (OS), “inflammation”, and “semen microbiota” in combination with “humans”, “rats”, and “mice”. Results: By following all evidence that fits in the pre-, post-, and vasectomy reversal (VR) stages, we identified a total of n = 210 studies from which only n = 21 were finally included following two procedures of eligibility evaluation. Conclusions: The topic surrounding this intricate landscape has created debate since the current evidence is contradictory, limited, or does not exist. Starting from this consideration, we argue that further research is mandatory to decipher how a vasectomy might disturb homeostasis.

Surgical or radiological treatment for varicoceles in subfertile men

BACKGROUND

Varicoceles are associated with male subfertility; however, the mechanisms by which varicoceles affect fertility have yet to be satisfactorily explained. Several treatment options exist, including surgical or radiological treatment, however the safest and most efficient treatment remains unclear.  OBJECTIVES: To evaluate the effectiveness and safety of surgical and radiological treatment of varicoceles on live birth rate, adverse events, pregnancy rate, varicocele recurrence, and quality of life amongst couples where the adult male has a varicocele, and the female partner of childbearing age has no fertility problems.

SEARCH METHODS

We searched the following databases on 4 April 2020: the Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, and CINAHL. We also searched the trial registries and reference lists of articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) if they were relevant to the clinical question posed and compared different forms of surgical ligation, different forms of radiological treatments, surgical treatment compared to radiological treatment, or one of these aforementioned treatment forms compared to non-surgical methods, delayed treatment, or no treatment. We extracted data if the studies reported on live birth, adverse events, pregnancy, varicocele recurrence, and quality of life.

DATA COLLECTION AND ANALYSIS

Screening of abstracts and full-text publications, alongside data extraction and 'Risk of bias' assessment, were done dually using the Covidence software. When we had sufficient data, we calculated random-effects (Mantel-Haenszel) meta-analyses; otherwise, we reported results narratively. We used the I² statistic to analyse statistical heterogeneity. We planned to use funnel plots to assess publication bias in meta-analyses with at least 10 included studies. We dually rated the risk of bias of studies using the Cochrane 'Risk of bias' tool, and the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

We identified 1897 citations after de-duplicating the search results. We excluded 1773 during title and abstract screening. From the 113 new full texts assessed in addition to the 10 studies (11 references) included in the previous version of this review, we included 38 new studies, resulting in a total of 48 studies (59 references) in the review providing data for 5384 participants. Two studies (three references) are ongoing studies and two studies are awaiting classification. Treatment versus non-surgical, non-radiological, delayed, or no treatment Two studies comparing surgical or radiological treatment versus no treatment reported on live birth with differing directions of effect. As a result, we are uncertain whether surgical or radiological treatment improves live birth rates when compared to no treatment (risk ratio (RR) 2.27, 95% confidence interval (CI) 0.19 to 26.93; 2 RCTs, N = 204; I² = 74%, very low-certainty evidence). Treatment may improve pregnancy rates compared to delayed or no treatment (RR 1.55, 95% CI 1.06 to 2.26; 13 RCTs, N = 1193; I² = 65%, low-certainty evidence). This suggests that couples with no or delayed treatment have a 21% chance of pregnancy, whilst the pregnancy rate after surgical or radiological treatment is between 22% and 48%. We identified no evidence on adverse events, varicocele recurrence, or quality of life for this comparison. Surgical versus radiological treatment We are uncertain about the effect of surgical versus radiological treatment on live birth and on the following adverse events: hydrocele formation, pain, epididymitis, haematoma, and suture granuloma. We are uncertain about the effect of surgical versus radiological treatment on pregnancy rate (RR 1.13, 95% CI 0.75 to 1.70; 5 RCTs, N = 456, low-certainty evidence) and varicocele recurrence (RR 1.31, 95% CI 0.82 to 2.08; 3 RCTs, N = 380, low-certainty evidence). We identified no evidence on quality of life for this comparison. Surgery versus other surgical treatment We identified 19 studies comparing microscopic subinguinal surgical treatment to any other surgical treatment. Microscopic subinguinal surgical treatment probably improves pregnancy rates slightly compared to other surgical treatments (RR 1.18, 95% CI 1.02 to 1.36; 12 RCTs, N = 1473, moderate-certainty evidence). This suggests that couples with microscopic subinguinal surgical treatment have a 10% to 14% chance of pregnancy after treatment, whilst the pregnancy rate in couples after other surgical treatments is 10%. This procedure also probably reduces the risk of varicocele recurrence (RR 0.48, 95% CI 0.29, 0.79; 14 RCTs, N = 1565, moderate-certainty evidence). This suggests that 0.4% to 1.1% of men undergoing microscopic subinguinal surgical treatment experience recurrent varicocele, whilst 1.4% of men undergoing other surgical treatments do. Results for the following adverse events were inconclusive: hydrocele formation, haematoma, abdominal distension, testicular atrophy, wound infection, scrotal pain, and oedema. We identified no evidence on live birth or quality of life for this comparison. Nine studies compared open inguinal surgical treatment to retroperitoneal surgical treatment. Due to small sample sizes and methodological limitations, we identified neither treatment type as superior or inferior to the other regarding adverse events, pregnancy rates, or varicocele recurrence. We identified no evidence on live birth or quality of life for this comparison. Radiological versus other radiological treatment One study compared two types of radiological treatment (sclerotherapy versus embolisation) and reported 13% varicocele recurrence in both groups. Due to the broad confidence interval, no valid conclusion could be drawn (RR 1.00, 95% CI 0.16 to 6.20; 1 RCT, N = 30, very low-certainty evidence). We identified no evidence on live birth, adverse events, pregnancy, or quality of life for this comparison.

AUTHORS' CONCLUSIONS

Based on the limited evidence, it remains uncertain whether any treatment (surgical or radiological) compared to no treatment in subfertile men may be of benefit on live birth rates; however, treatment may improve the chances for pregnancy. The evidence was also insufficient to determine whether surgical treatment was superior to radiological treatment. However, microscopic subinguinal surgical treatment probably improves pregnancy rates and reduces the risk of varicocele recurrence compared to other surgical treatments. High-quality, head-to-head comparative RCTs focusing on live birth rate and also assessing adverse events and quality of life are warranted.

A Novel Approach to Improving the Reliability of Manual Semen Analysis: A Paradigm Shift in the Workup of Infertile Men

Conventional semen analysis (SA) is an essential component of the male infertility workup, but requires laboratories to rigorously train and monitor technicians as well as regularly perform quality assurance assessments. Without such measures there is room for error and, consequently, unreliable results. Furthermore, clinicians often rely heavily on SA results when making diagnostic and treatment decisions, however conventional SA is only a surrogate marker of male fecundity and does not guarantee fertility. Considering these challenges, the last several decades have seen the development of many advances in SA methodology, including tests for sperm DNA fragmentation, acrosome reaction, and capacitation. While these new diagnostic tests have improved the scope of information available to clinicians, they are expensive, time-consuming, and require specialized training. The latest advance in laboratory diagnostics is the measurement of seminal oxidation-reduction potential (ORP). The measurement of ORP in an easy, reproducible manner using a new tool called the Male Infertility Oxidative Stress System (MiOXSYS) has demonstrated ORP's potential as a feasible adjunct test to conventional SA. Additionally, the measurement of ORP by this device has been shown to be predictive of both poor semen quality and male infertility. Assessing ORP is a novel approach to both validating manual SA results and identifying patients who may benefit from treatment of male oxidative stress infertility.

Ultrasound evaluation of varicoceles: systematic literature review and rationale of the ESUR-SPIWG Guidelines and Recommendations

Although often asymptomatic and detected incidentally, varicocele is a relatively common problem in patients who seek medical attention for infertility problems. Ultrasound (US) is the imaging modality of choice for evaluation, but there is no consensus on the diagnostic criteria, classification, and examination technique. In view of this uncertainty, the Scrotal and Penile Imaging Working Group of the European Society of Urogenital Radiology (ESUR-SPIWG) undertook a systematic review of the available literature on this topic, to use as the basis for evidence-based guidelines and recommendations. This paper provides the results of the systematic review on which guidelines were constructed.

Association between seminal granulysin and malondialdehyde in infertile men with varicocele and the potential effect of varicocelectomy

This study assessed the seminal plasma granulysin and malondialdehyde (MDA) levels in patients suffering from varicocele-associated infertility prior to and after varicocelectomy. This study was conducted on 34 infertile men with varicocele (group A) and same patients after varicocelectomy (group B) and 32 fertile normozoospermic males (group C). A detailed history taking, clinical examination, scrotal doppler ultrasound for varicocele diagnosis and grading, semen analysis and estimation of seminal granulysin and MDA before and after varicocelectomy were done to all participants. The mean (SD) granulysin and MDA levels in patients with varicocele were higher than in controls with highly significant differences. Post-operatively, there was a significant reduction in mean (SD) granulysin and in MDA level. Basal seminal granulysin positively correlated with basal seminal MDA, abnormal forms and negatively correlated with basal sperm count, concentration, and progressive motility. The receiver operating characteristic curve of seminal granulysin and MDA levels were conducted for discrimination between infertility cases with varicocele and control groups. Excellent AUCs were found for both markers (AUC = 0.971, 0.991 respectively). We concluded that high levels of granulysin and MDA in the semen of infertile males with varicocele negatively impact their spermatogenesis. Varicocelectomy leads to the improvement of semen parameters and significantly decreases seminal plasma granulysin and MDA levels. Hence, seminal granulysin and MDA could be used as a prognostic test in infertile patients with varicocele.

Microsurgical varicocelectomy effect on sperm telomere length, DNA fragmentation and seminal parameters

Varicocele is one of the main causes of male infertility and microsurgical varicocelectomy (MV) seems to be the best procedure for its repair and to reduce testicular oxidative stress (ROS). As ROS causes guanine modifications, we postulated that DNA damage could be more intense in telomeres due to their G-rich nature. We studied the effect of MV on sperm telomere length (TL), single- and double-strand DNA fragmentation (ssSDF and dsSDF) and seminal parameters. Sperm telomeres from 12 fertile donors and 20 varicocele patients before and nine months after MV were labelled using FITC-PNA qFISH (a new method to obtain absolute TL from relative fluorescence intensity using FITC-fluorescent spheres). Both ssSDF and dsSDF were analysed using the alkaline and neutral Comet assays, respectively. The results showed that varicocele and MV had no effect on TL. Seminal parameters, ssSDF and dsSDF of varicocele patients were altered. Although these parameters improved after MV, values did not reach those seen in fertile donors. A good estimation of absolute TL was developed based on FITC-fluorescent spheres. The results showed that TL is not affected by varicocele or surgery. However, MV is able to partially reduce altered seminal parameters, ssSDF and dsSDF values in varicocele patients.

Comparison of outcomes in intrauterine insemination, in vitro fertilisation and intracytoplasmic sperm injection in men with and without varicocele

Objectives: To investigate the differences in clinical pregnancy, miscarriage, and live birth rates when male partners were diagnosed with a varicocele and to compare these outcomes to those without and study the outcomes based on the grade of varicocele. Methods: The retrospective study was based on a cohort of consecutive infertile couples undergoing assisted reproductive technology (ART) at the Reproductive Center of Shandong Provincial Hospital affiliated to the Shandong University during the period between January 2017 and December 2018. A total of 4203 couples comprised of men with and without varicocele undergoing the first ART cycle (1501 intrauterine inseminations (IUI), 1623 in vitro fertilisations (IVF) and 1079 intracytoplasmic sperm injections (ICSI)) were included. Semen parameters and ART outcomes were determined. Results: ICSI (26.5%) originated from men with a significant lower level in sperm concentration and motility but with a strict normal morphology had a higher prevalence of varicocele than men undergoing IUI (20.7%) and IVF (18.1%). In IUI, the odds ratios (ORs) for pregnancy and live birth were significantly lower for couples in men diagnosed with grades 1 or 2 varicocele as compared to those for men with grade 3 varicocele. In IVF, ORs for live birth where men were diagnosed with grades 1 or 2 varicocele were also lower than those for men with grade 3,whereas a higher miscarriage rate was found when men had grades 1 or 2 varicocele than when men had grade 3. However, for ICSI, no significant outcomes were found in grades 1, 2 or 3 varicocele versus the no varicocele group. Conclusions: The increasing grade of varicocele was negatively associated with sperm parameters and can alter the outcome of further IUI/IVF.

Left spermatic vein reflux after varicocele repair predicts pregnancies and live births in subfertile couples

PURPOSE

Varicocele repair (VR) is proposed to improve fertility in subfertile couples with a poor semen quality. We explored whether the disappearance of a left continuous spermatic venous reflux (SVR) at scrotal colour-Doppler ultrasound (CDUS), an objective evidence for a VR, is predictive for improved fertility outcome in subfertile couples.

METHODS

VR was performed by left internal spermatic vein sclero-embolisation in 88 males seeking a consultation for subfertility. Semen analysis and scrotal CDUS were evaluated before and 6 months after VR. Serum levels of FSH and total testosterone (TT) were obtained at baseline. Telephone interview was used to obtain information about fertility outcome. Significant predictors of pregnancy and live births, selected by univariate analyses, were included into multiple logistic regression models to assess independent associations.

RESULTS

At the adjusted model, independent significant predictors of pregnancy after VR were a disappeared SVR at CDUS (OR = 5.5, 97.5% CI 2.01-15.4; p = 0.0009) and an improved sperm total motile count (TMC) (OR = 5.5, 97.5% CI 1.4-27.9; p = 0.02). Even live births were independently associated with both disappeared left SVR at CDUS (OR = 4.3, 97.5% CI = 1.6-11.8; p = 0.003) and improved TMC after VR (OR = 4.8, 97.5% CI 1.3-24.2; p = 0.02).

CONCLUSION

The still controversial effect of varicocele repair on fertility in subfertile couples may reside on the undefined objective methods to document a successful VR and its effect on couple fertility. The disappearance of a continuous left SVR at CDUS after VR was the objective best predictor for subsequent improved fertility in subfertile couples.

Treating varicocele in 2018: current knowledge and treatment options

PURPOSE

Varicocele is defined as a state of varicosity and tortuosity of the pampiniform plexus around the testis caused by retrograde blood flow through the internal spermatic vein. The prevalence of clinically relevant varicocele ranges from 5 to 20% in the male population and is often associated with infertility and reduction of sperm quality. In this review, the pathophysiology and clinical aspects of varicocele are reviewed along with therapeutic options and treatment effects on sperm parameters and fertility both in adult and in pediatric/adolescent subjects.

METHODS

We conducted a Medline and a PubMed search from 1965 to 2018 to identify publications related to varicocele clinical aspects, treatment procedures and treatment outcomes. Keywords used for the search were: "varicocele", "varicocelectomy", "sclerotherapy", "male infertility", "subfertility", and "semen abnormalities".

RESULTS

Data from a large number of studies in adolescent and adult males indicate that varicocele correction improves semen parameters in the majority of patients, reducing oxidative stress and improving sperm nuclear DNA integrity either with surgical or percutaneous approach.

CONCLUSIONS

Varicocele repair seems to represent a cost-effective therapeutic option for all males (both adolescent and adults) with a clinical varicocele in the presence of testicular hypotrophy, worsening sperm alterations or infertility. On the other hand, some investigators questioned the role of varicocelectomy in the era of assisted reproduction. Thus, a better understanding of the pathophysiology of varicocele-associated male subfertility is of paramount importance to elucidating the deleterious effects of varicocele on spermatogenesis and possibly formulating new treatment strategies.

Varicocele repair in patients prepared for intracytoplasmic sperm injection: To do or not to do?

PURPOSE

This study sought to evaluate the impact of varicocele repair on intracytoplasmic sperm injection outcomes.

PATIENTS AND METHODS

A prospective comparative study was conducted at the Assisted Reproduction Unit, International Islamic Center for Population Studies and Researches, Al-Azhar University. This study included 100 non-azoospermic infertile men with a history of varicocele who were scheduled for intracytoplasmic sperm injection, half of them had already undergone prior subinguinal varicocelectomy at least 12 months prior to ICSI without clinically evident recurrence (treated group 1), and the other half has any grade of an unrepaired clinical varicocele (untreated group 2) at sperm injection. All cases were clinically evaluated and eligible for analysis by using inclusion and exclusion criteria. ICSI outcomes compared between the two groups, including fertilisation rate, embryo development rate and pregnancy outcome.

RESULTS

Our study did not show any significant difference between treated and untreated groups regarding the mean values of fertilisation (0.7759 ± 0.2708 vs. 0.7119 ± 0.3057, p = 0.2708), embryo development (0.7759 ± 0.2708 vs. 0.6991 ± 0.3211, p = 0.1990) or different embryo grades. There was no statistically significant difference between groups regarding pregnancy occurrence rates (p = 0.0928).

CONCLUSION

Infertile men scheduled for ICSI do not seem to benefit from varicocele repair as regard to the outcomes of ICSI.

Role of varicocele treatment in assisted reproductive technologies

Objective

In this review, we investigate the advantage of varicocele repair prior to assisted reproductive technologies (ART) for infertile couples and provide cost analysis information.

Materials and methods

We searched the following electronic databases: PubMed, Medline, Excerpta Medica Database (Embase), Cumulative Index to Nursing and Allied Health Literature (CINAHL). The following search strategy was modified for the various databases and search engines: 'varicocele', 'varicocelectomy', 'varicocele repair', 'ART', 'in vitro fertilisation (IVF)', 'intracytoplasmic sperm injection (ICSI)'.

Results

A total of 49 articles, including six meta-analyses, 32 systematic reviews, and 11 original articles, were included in the analysis. Bypassing potentially reversible male subfertility factors using ART is currently common practice. However, varicocele may be present in 35% of men with primary infertility and 80% of men with secondary infertility. Varicocele repair has been shown to be an effective treatment for infertile men with clinical varicocele, thus should play an important role in the treatment of such patients due to the foetal/genetic risks and high costs that are associated with increased ART use.

Conclusion

Varicocele repair is a cost-effective treatment method that can improve semen parameters, pregnancy rates, and live-birth rates in most infertile men with clinical varicocele. By improving semen parameters and sperm structure, varicocele repair can decrease or even eliminate ART requirement.

Spermatozoal Fractalkine Signaling Pathway Is Upregulated in Subclinical Varicocele Patients with Normal Seminogram and Low-Level Leucospermia

Background

Fractalkine is produced in seminal plasma in small amounts and correlates with sperm motility.

Purpose

To investigate the possible effect of low-level leucospermia on spermatozoa oxidative stress and sDNA fragmentation in patients with subclinical varicocele and apparently normal seminogram, and also to study the role of spermatozoal fractalkine and its receptor (CX3CR1) gene expression as a marker of spermatozoa inflammatory response.

Methods

This study included 80 patients with subclinical varicocele (45 fertile and 35 infertile) and 45 age-matched fertile volunteers. In semen samples, fractalkine and CX3CR1 gene expression were investigated by qRT-PCR. Moreover, seminal plasma malondialdehyde (MDA) and total antioxidant capacity (TAC) were measured.

Results

There are significant decrease in semen quality and significant increase in seminal leucocytes count in subclinical varicocele. Our results show a significant increase in MDA and TAC levels, DNA fragmentation, and expression levels of fractalkine and its receptor (CX3CR1) in subclinical varicocele groups.

Conclusion

Subclinical varicocele induces seminal and spermatozoal subclinical inflammatory response in the form of low-level leucospermia and increased mRNA expression of the fractalkine signaling pathway, leading to increased spermatozoal ROS production, oxidative stress, and DNA fragmentation. These could cooperate in the pathogenesis of delayed fertility in males with subclinical varicocele.

Y chromosome microdeletions and varicocele as aetiological factors of male infertility: A cross-sectional study

The pathogenic mechanisms by which varicocele disrupt spermatogenesis are not clearly understood. Over 30% of male infertility cases resulting from spermatogenic problems are associated with genetic abnormalities, and Y chromosome microdeletions are the second most frequent genetic cause. Here, we aimed to evaluate the frequency of Y chromosome microdeletion in infertile men with varicocele. A cross-sectional study comprising 51 infertile men with varicocele presenting spermatogenesis failures was performed. Y chromosome microdeletion research was made using polymerase chain reaction. Of the 51 men with infertility and varicocele, 35.3% (18/51) had nonobstructive azoospermia and 64.7% had severe oligozoospermia. Y chromosome microdeletion was found in two cases (3.9%): one patient had nonobstructive azoospermia and complete microdeletion of the AZFb and AZFc regions, and another patient had severe oligozoospermia and complete microdeletion of the AZFc region. Although in recent years, a genetic aetiology related to Y chromosome microdeletions has become a major cause of infertility in males with spermatogenesis failures, in this study, the varicocele was the clinical cause of seminal abnormalities that could lead to infertility, suggesting that both varicocele and Y chromosome microdeletion aetiologies can present, alone or combined, as factors of male infertility.

JG. Semen parameters in men with varicocele: DNA fragmentation, chromatin packaging, mitochondrial membrane potential, and apoptosis

OBJECTIVE

To evaluate varicocele effects on conventional semen parameters: sperm DNA fragmentation, chromatin packaging, mitochondrial membrane potential (MMP) and sperm apoptosis.

METHODS

A cross-sectional study was carried out with semen samples from 2,399 men of couples who attended an infertility clinic. A total of 16.3% (391/2399) of the men were diagnosed with varicocele by a urologist.

RESULTS

A regression analysis revealed that the percentages of sperm with DNA fragmentation, abnormal chromatin packaging, and abnormal MMP were significantly increased in individuals with varicocele, when compared to men without varicocele. Apoptosis was not influenced by varicocele. Conventional semen parameters were significantly worse in individuals with the disease. On the other hand, in men with varicocele, Spearman's correlation demonstrated that early apoptosis and abnormal MMP showed a positive and significant correlation with sperm DNA fragmentation.

CONCLUSION

Men with varicocele had worse semen parameters, including increased levels of sperm DNA fragmentation, inactive mitochondria, and abnormal chromatin packaging. These changes are possible causes of infertility in individuals with varicocele.

An association between sperm PLCζ levels and varicocele?

PURPOSE

We aimed to compare the expression of phospholipase C ζ (PLCζ), as one of the main sperm factors involved in oocyte activation, at both RNA and protein levels in fertile men and those with varicocele.

METHODS

This study included 35 individuals with male factor infertility presenting primary infertility with grade II and III unilateral varicocele and 20 fertile men without varicocele. Semen parameters were assessed according to WHO 2010. Sperm DNA fragmentation, relative expression of PLCζ at messenger RNA, and protein levels were evaluated by sperm chromatin structure assay (SCSA), real-time PCR, and Western blot analysis, respectively.

RESULTS

The results of this study reveal that the mean relative expression of PLCζ was significantly lower in individuals with varicocele compared to fertile men at both transcription and translation levels. In addition, the percentage of DNA fragmentation was significantly higher in infertile men with varicocele compared to fertile men.

CONCLUSIONS

The findings of the present study illustrate that one of the etiologies of reduced fertility associated with varicocele is the low expression of PLCζ. This effect could subsequently reduce the sperm ability to induce oocyte activation. Therefore, these results hold promise to modify our understanding of reproductive physiology of varicocele state.