Varicocele associated male infertility: cellular and molecular perspectives of pathophysiology

Type 1 diabetes impairs the activity of rat testicular somatic and germ cells through NRF2/NLRP3 pathway-mediated oxidative stress

Background

It is well known that metabolic disorders, including type 1 diabetes (T1D), are often associated with reduced male fertility, mainly increasing oxidative stress and impairing the hypothalamus-pituitary-testis (HPT) axis, with consequently altered spermatogenesis and reduced sperm parameters. Herein, using a rat model of T1D obtained by treatment with streptozotocin (STZ), we analyzed several parameters of testicular activity.

Methods

A total of 10 adult male Wistar rats were divided into two groups of five: control and T1D, obtained with a single intraperitoneal injection of STZ. After 3 months, the rats were anesthetized and sacrificed; one testis was stored at -80°C for biochemical analysis, and the other was fixed for histological and immunofluorescence analysis.

Results

The data confirmed that T1D induced oxidative stress and, consequently, alterations in both testicular somatic and germ cells. This aspect was highlighted by enhanced apoptosis, altered steroidogenesis and Leydig cell maturity, and impaired spermatogenesis. In addition, the blood-testis barrier integrity was compromised, as shown by the reduced levels of structural proteins (N-cadherin, ZO-1, occludin, connexin 43, and VANGL2) and the phosphorylation status of regulative kinases (Src and FAK). Mechanistically, the dysregulation of the SIRT1/NRF2/MAPKs signaling pathways was proven, particularly the reduced nuclear translocation of NRF2, affecting its ability to induce the transcription of genes encoding for antioxidant enzymes. Finally, the stimulation of testicular inflammation and pyroptosis was also confirmed, as highlighted by the increased levels of some markers, such as NF-κB and NLRP3.

Conclusion

The combined data allowed us to confirm that T1D has detrimental effects on rat testicular activity. Moreover, a better comprehension of the molecular mechanisms underlying the association between metabolic disorders and male fertility could help to identify novel targets to prevent and treat fertility disorders related to T1D.

Anti-sperm Antibody Positivity in Men with Varicocele: A Systematic Review and Meta-Analysis

PURPOSE

Despite the significant role of varicocele in the pathogenesis of male infertility, its association with anti-sperm antibodies (ASA) remains controversial. This systematic review and meta-analysis (SRMA) aims to investigate the frequency of ASA positivity in men with varicocele.

MATERIALS AND METHODS

This SRMA is conducted in accordance with the Meta-analysis of Observational Studies in Epidemiology guidelines. We investigated the frequency of ASA positivity in ejaculates or serum of men with varicocele as compared to men without varicocele (controls). A literature search was performed using the Scopus and PubMed databases following the Population Exposure Comparison Outcome, Study Design model. Data extracted from eligible studies were meta-analyzed and expressed as odds ratios (ORs) and confidence intervals (CIs).

RESULTS

Out of 151 abstracts identified during the initial screening, 6 articles met the inclusion criteria and were included in the meta-analysis. Using mixed antiglobulin reaction (MAR) assay, 61 out of the 153 (39.8%) patients with varicocele tested positive for ASA in their ejaculates as compared to 22 out of the 129 control subjects (17%, OR=4.34 [95% CI: 1.09-17.28]; p=0.04). Using direct or indirect immunobead test, 30 out of 60 cases diagnosed with varicocele (50%) had shown ASA positivity in their ejaculates as compared to 16 out of 104 controls (15.4%, OR=3.57 [95% CI: 0.81-15.68]; p=0.09). Using enzyme-linked immunosorbent assay (ELISA), out of 89 varicocele patients, 33 (37.1%) tested positive for serum ASA as compared to 9 out of 57 participants in the control group (15.8%, OR=7.87 [95% CI: 2.39-25.89]; p<0.01).

CONCLUSIONS

This SRMA indicates that ASA positivity is significantly higher among men with varicocele when tested by direct method (MAR) or indirect method (ELISA). This data suggests an immunological pathology in infertile men with varicocele and may have implications for the management of these patients.

Clinical Utility of Sperm Function Tests in Predicting Male Fertility: A Systematic Review

Routine semen analysis provides considerable information regarding sperm parameters; however, it is not solely adequate to predict male fertility potential. In the past two decades, several advance sperm function tests have been developed. The present systematic review intends to assess the clinical utility of available advance sperm function tests in predicting the male fertility potential. A systematic literature search was conducted as per PRISMA guidelines using PubMed, MEDLINE, Google Scholar, and Cochrane Library. Different keywords either singly or in combination were used to retrieve the relevant articles related to sperm function tests, male fertility, and pregnancy outcomes. A total of 5169 articles were obtained, out of which 110 meeting the selection criteria were included in this review. The majorly investigated sperm function tests are hypo-osmotic swelling test, acrosome reaction test, sperm capacitation test, hemizona binding assay, sperm DNA fragmentation test, seminal reactive oxygen species test, mitochondrial dysfunction tests, antisperm antibody test, nuclear chromatin de-condensation (NCD) test, etc. The different advance sperm function tests analyse different aspects of sperm function. Hence, any one test may not be helpful to appropriately predict the male fertility potential. Currently, the unavailability of high-quality clinical data, robust thresholds, complex protocols, high cost, etc., are the limiting factors and prohibiting current sperm function tests to reach the clinics. Further multi-centric research efforts are required to fulfil the existing lacunas and pave the way for these tests to be introduced into the clinics.

Redox Homeostasis and Nrf2-Regulated Mechanisms Are Relevant to Male Infertility

Infertility represents a significant global health challenge, affecting more than 12% of couples worldwide, and most cases of infertility are caused by male factors. Several pathological pathways are implicated in male infertility. The main mechanisms involved are driven by the loss of reduction-oxidation (redox) homeostasis and the resulting oxidative damage as well as the chronic inflammatory process. Increased or severe oxidative stress leads to sperm plasma membrane and DNA oxidative damage, dysregulated RNA processing, and telomere destruction. The signaling pathways of these molecular events are also regulated by Nuclear factor-E2-related factor 2 (Nrf2). The causes of male infertility, the role of oxidative stress in male infertility and the Keap1-Nrf2 antioxidant pathway are reviewed. This review highlights the regulatory role of Nrf2 in the balance between oxidants and antioxidants as relevant mechanisms to male fertility. Nrf2 is involved in the regulation of spermatogenesis and sperm quality. Establishing a link between Nrf2 signaling pathways and the regulation of male fertility provides the basis for molecular modulation of inflammatory processes, reactive oxygen species generation, and the antioxidant molecular network, including the Nrf2-regulated antioxidant response, to improve male reproductive outcomes.

Understanding the impact of varicocele on sperm capacitation

OBJECTIVE

To study the relationship between the seminal sample quality of men with varicocele and sperm capacitation.

DESIGN

Cross-sectional observational study.

SETTING

Academic hospital.

PATIENT(S)

Seventy-six men (19 control and 57 with varicocele) were analyzed.

INTERVENTION(S)

Semen samples were submitted to a discontinuous density gradient for sperm selection. Sperm capacitation was induced using a human tubal fluid medium supplemented with bovine serum albumin.

MAIN OUTCOME MEASURE(S)

After capacitation induction, the sperm were assessed by capacitation state, computer-assisted sperm motility, mitochondrial activity, membrane integrity, acrosome reaction, and intracellular oxidative stress.

RESULT(S)

The capacitation period increased sperm motility, showing an increase in the average path velocity and a decrease in the straightness compared with sperm before capacitation (paired analysis). After capacitation, the rate of capacitated sperm, motility, and mitochondrial activity showed differences between groups (control and varicocele). The varicocele group showed lower mitochondrial activity and capacitation than the control group. On the other hand, no significant differences were observed in the other variables evaluated.

CONCLUSION(S)

Varicocele men showed less viable sperm and mitochondrial activity than control men after capacitation sperm. The induction of capacitation altered motility by increasing path velocity and decreasing straightness in all of the studied groups, evidencing the occurrence of hyperactivation.

Impact of body mass index on semen parameters and reproductive hormones among men undergoing microsurgical subinguinal varicocelectomy

Background

Few studies assessed the relationships between BMI and post varicocelectomy semen quality and fertility potential and they reported inconsistent findings.

Objective

To assess the association of BMI with semen parameters and reproductive hormones before and after microsurgical varicocelectomy.

Materials and Methods

Retrospective chart review in a tertiary infertility center. Of 1170 patients with clinical varicocele during the study period (8 years), 813 patients were eligible and included. Patients were grouped into: Group A (kg/m2, n = 251 patients), B (BMI 25-29.9 kg/m2, n = 289), C (BMI 30-34.9 kg/m2, n = 183) and D (kg/m2, n = 90). Clinical data, semen parameters, sperm DNA fragmentation and hormonal profile were collected before and 3 months after microsurgical varicocelectomy.

Results

Patients' mean age was 35.87 ± 8.17 years. Higher-grade varicocele was significantly more prevalent in the lower BMI groups. BMI was significantly negatively correlated with preoperative sperm concentration, total motility progressive motility and total motile sperm count. Pre-operatively, sperm concentration, total motility, progressive motility and total motile sperm count showed significant differences between BMI groups, where higher BMI (Groups C and D) exhibited the poorest semen parameters. Postoperatively, all groups showed significant improvement in sperm concentration compared with pre-operative values. However, total and progressive motility were significantly improved in Groups A, B and C, while in Group D (highest BMI), total motility improved clinically but not statistically, progressive motility did not display improvement, and total motile sperm count was significantly improved only in Groups B and C. Postoperatively, mean improvements in semen parameters across the BMI groups were not significantly different, except for morphology, which improved significantly more in the less obese patients.

Conclusion

For infertile patients with clinical varicocele undergoing micro-surgical varicocelectomy, BMI appears not to impact the improvements across most of the semen parameters and hormones. The procedure might improve the fertility potential.

The efficacy and mechanism of acupuncture in the treatment of male infertility: A literature review

Fertility, a social, cultural, and medical issue, has aroused public attention because of its potential to predict future health. In recent years, the incidence of male infertility has increased significantly, and various risk factors, such as congenital factors, acquired factors, and idiopathic factors, have led to this situation. Male infertility causes substantial psychological and social distress in patients. With the implementation of the two-child policy, male infertility has brought enormous psychological and social pressure and huge economic burden to patients and the healthcare system. This has attracted the attention of not only men of childbearing age but also many male experts. The conventional therapeutic approaches for treating male infertility, including drugs, varicocele surgery, intrauterine insemination, in vitro fertilization, and intracytoplasmic sperm injection, can restore fertility to a certain extent, but their efficacy is far from satisfactory, not to mention some adverse events. Therefore, acupuncture has been chosen by many men to treat their infertility and produced significant effects. In the present paper, the efficacy and mechanism of acupuncture in the treatment of male infertility were analyzed from different perspectives such as regulating hormone secretion, reducing inflammation, and improving semen parameters. The existing literature shows that acupuncture can effectively treat male infertility.