Synergistic effect of androgen receptor (CAG repeat length) and endothelial nitric oxide synthase (Glu298Asp variant) gene polymorphisms on seminal parameters in men with idiopathic oligoasthenozoospermia

eNOS polymorphisms on male infertility: An updated systematic review and meta-analysis

BACKGROUND

This meta-analysis was performed to examine the association of 3 endothelial nitric oxide synthase (eNOS) gene polymorphisms with male infertility.

METHODS

The literature on the relation between the mutant of eNOS and male infertility before July 1, 2022, was conducted in Pubmed, Medline, and Web of Science. The search strategy is as follows: (eNOS OR ECNOS OR nitric oxide synthase 3 OR NOS3) AND (polymorphism OR mutation OR variation OR SNP OR genotype) AND (male infertility). Statistical analysis was performed with the web of MetaGenyo, Stata 12, trial sequential analysis 0.9Beta, and the web of GTEx.

RESULTS

Overall, 13 studies (26 case-controls) were included involving 6518 cases and 5461 controls for 3 polymorphisms (rs2070744, rs1799983, rs61722009) of eNOS. We found that eNOS rs2070744 was correlated with an increased risk of male infertility (C vs. T: odds ratio [OR], 1.48; 95% confidence interval [CI], [1.19-1.85]; CC vs. TT: OR, 2.59; 95% CI, [1.40-4.80]; CT vs. TT: OR, 1.17; 95% CI, [1.00-1.38]; CC vs. CT + TT: OR, 2.50; 95% CI, [1.35-4.62]; CC + CT vs. TT: OR, 1.41; 95% CI, [1.21-1.64]). And eNOS rs1799983 was correlated with an increased risk of male infertility (allele contrast T vs. G: OR, 1.41; 95% CI, [1.01-1.96]; P = .043; recessive model TT vs. TG + GG: OR, 2.00; 95% CI, [1.03-3.90]; P = .042). In the stratified analysis of rs61722009, we found Asians might be correlated with an increased risk of male infertility (4a vs. 4b: OR, 1.50; 95% CI, [0.94-2.38]; 4a4a vs. 4b4b: OR, 2.56; 95% CI, [0.70-9.38]; 4a4b vs. 4b4b: OR, 1.36; 95% CI, [0.87-2.13]; 4a4a vs. 4a4b + 4b4b: OR, 2.57; 95% CI, [0.91-7.30]; 4a4a + 4a4b vs. 4b4b: OR, 1.44; 95% CI, [0.87-2.40]).

CONCLUSION

The eNOS rs2070744 polymorphism and rs1799983 are associated with the risk of male infertility, and rs61722009 might be a risk factor for Asians.

Yangjing capsule improves oligoasthenozoospermia by promoting nitric oxide production through PLCγ1/AKT/eNOS pathway

Background: Oligoasthenozoospermia is an important factor leading to male infertility. Yangjing capsule (YC), a traditional Chinese preparation, displays beneficial effects on male infertility. However, whether YC could improve oligoasthenozoospermia remains unclear. Methods: In this study, we aimed to explore the effect of YC in the treatment of oligoasthenozoospermia. Male Sprague-Dawley (SD) rats were treated with 800 mg/kg ornidazole once daily for 30 days to induce in vivo oligoasthenozoospermia; primary Sertoli cells were treated with 400 μg/mL ornidazole for 24 h to induce in vitro oligoasthenozoospermia. Results: We found that YC improved the testicle and epididymis weight, sperm concentration, sperm progressive motility, serum testosterone, fertility rate and testis morphology in ornidazole-exposed rats and enhanced cell survival in ornidazole-stimulated primary Sertoli cells. YC also inhibited the ornidazole-caused decrease in nitric oxide (NO) generation and the phosphorylation of phospholipase C γ1 (PLCγ1), AKT, and eNOS in vivo and in vitro in oligoasthenozoospermia. Furthermore, the knockdown of PLCγ1 blunted the beneficial effects of YC in vitro. Conclusion: Collectively, our data suggested that YC protected against oligoasthenozoospermia by promoting NO levels through the PLCγ1/AKT/eNOS pathway.

Can extremely low frequency magnetic field affect human sperm parameters and male fertility?

Exposure to extremely low frequency magnetic fields (ELF-MF) may have different effects on spermatozoa depending on the waveform, magnetic flux density, frequency of ELF-MF, and duration of exposure. In this study, we investigated the possible role of ELF-MF (50 Hz; 1 mT) exposure in altering sperm parameters. In this study we found that exposure to ELF-MF at the frequency of 50 Hz (1 mT) for two hours induces statistically significant alterations in progressive motility, morphology and reactive oxygen species (ROS) production of human spermatozoa, suggesting a role of ELF-MF in altering reproductive function of spermatozoa. Our results represent an important discovery in the field since occupational exposure to the sine waveform 1 mT 50 Hz ELF-MF used in our study is possible in workplace. Moreover, these electromagnetic fields are product by many electronic devices and household appliances. Thus, alterations of progressive motility and morphology of spermatozoa would be important consequences of human exposures to ELF-MF.

Polymorphisms of androgens-related genes and idiopathic male infertility in Turkish men

Androgens, testosterone and dihydrotestosterone (DHT) are endocrine regulators of spermatogenesis and act via androgen receptor (AR). The aim of this study was to investigate the association(s) of AR (CAG repeat length), SRD5A2 (rs523349, V89L) and TNF-α (rs1800629, -308G/A) polymorphisms with idiopathic male infertility in Turkish men. This case-control study consisted of 312 men with idiopathic infertility and 113 fertile men. Polyacrylamide gel electrophoresis (PAGE) or PCR-restriction fragment length polymorphism methods were used for genotyping. The mean AR CAG repeat length was significantly longer in infertile men than in fertile men (p = 0.015). However, there was no significant association between the SRD5A2 genotypes (VV, VL and LL) and the risk of infertility (p = 0.516). The genotype frequency and allele distribution of TNF-α -308G/A polymorphism (GG, GA, AA genotypes and G, A alleles) were not associated with male infertility (p = 0.779 and p = 0.743 respectively). AR CAG repeat expansion might be one of the risk factors for idiopathic male infertility in Turkish men. Further studies investigating the association of male infertility with AR CAG, V89L and -308G/A polymorphisms are warranted to understand the possible associations among them.

Association between androgen receptor polymorphic CAG and GGC repeat lengths and cryptorchidism: A meta-analysis of case-control studies

INTRODUCTION

Previous studies have revealed the relationship between androgen receptor (AR) CAG and/or GGC polymorphisms and risk of cryptorchidism, yet the results have been elusive and controversial.

AIM

To determine whether AR polymorphic CAG and/or GGC repeats are related to cryptorchidism.

STUDY DESIGN

The relevant studies were obtained from PubMed, Embase, China National Knowledge Infrastructure, and Wanfang. The pooled odds ratios with 95% confidence intervals (CIs) were used to assess the strength of associations. Subgroup analyses were performed based on ethnicity and source of controls. Moreover, Begg's funnel plots and Egger's linear regression test were conducted to determine publication bias.

RESULTS

Eight case-control studies containing 321 patients and 784 normal controls were included. There was a significant association between longer CAG repeats and cryptorchidism risk (weighted mean difference (WMD) = 0.62; 95% CIs 0.06, 1.18; P = 0.031). Moreover, there was a significant association between the longer GGC repeats and cryptorchidism risk (WMD = 0.87; 95% CIs 0.04, 1.74; P = 0.040). There was significant association between the longer CAG repeats and bilateral cryptorchidism (WMD = 0.88; 95% CIs -0.18, 1.94; P = 0.011), while there was no significant association between the longer CAG repeats and unilateral cryptorchidism (WMD = -0.09; 95% CIs -0.50, 0.31; P = 0.554). There were significant associations between the longer GGC repeats and unilateral cryptorchidism (WMD = 0.88; 95% CIs -0.30, 2.05; P = 0.005) and bilateral cryptorchidism (WMD = 1.35; 95% CIs -0.52, 3.21; P = 0.000). Stratifying analysis revealed an association between longer CAG/GGC repeats and cryptorchidism in Caucasian populations from Europe (WMD = 0.73; 95% CIs 0.00, 1.46; P = 0.017), while there was no association with Asian populations.

DISCUSSION

This meta-analysis found that CAG/GGC repeats in the AR gene were longer in cryptorchidism patients compared to controls. Both the longer CAG repeats and GGC repeats in the AR gene were associated with cryptorchidism risk. The longer CAG repeats were associated with bilateral cryptorchidism, whereas the longer GGC repeats were associated with unilateral and bilateral cryptorchidism. Stratifying analysis revealed an association between longer CAG/GGC repeats and cryptorchidism in Caucasian populations from Europe, while there was no association between longer CAG/GGC repeats and cryptorchidism in Asian populations.

CONCLUSION

The CAG/GGC repeats in the AR gene were longer in cryptorchidism than in controls. Longer CAG repeats may play a role in determining bilateral cryptorchidism, and longer GGC repeats may play a role in determining unilateral and bilateral cryptorchidism. These observations were more applicable to Caucasian populations.

Androgen Receptor (AR) Gene (CAG)n and (GGN)n Length Polymorphisms and Symptoms in Young Males With Long-Lasting Adverse Effects After Finasteride Use Against Androgenic Alopecia

Introduction

Long-term adverse symptoms of men who used oral finasteride against androgenic alopecia have been recently described as post-finasteride syndrome (PFS).

Aim

To determine whether (CAG)n-rs4045402 and (GGN)n-rs3138869 polymorphisms in the androgen receptor (AR) gene are implicated in PFS.

Methods

AR polymorphisms were studied according to PFS symptoms in 66 white participants (31.8% Italian, 28.8% American, and 39.4% other).

Main Outcome Measures

Symptoms were investigated by an ad hoc 100-item questionnaire and the Arizona Sexual Experience Scale and Aging Male Symptom Scale (AMS). (CAG)n and (GGN)n repeats were categorized as short ([CAG]9–19, [GGN]<23), medium ([CAG]20–24, [GGN]23), or long ([CAG]25–37, [GGN]>23).

Results

Median age was 32 years, duration of finasteride use was 360 days, and time from finasteride discontinuation was 1,053 days. We observed several frequency differences in symptoms according to (CAG)n and (GGN)n repeat numbers. Three AMS items were worse for medium (GGN)23 than for long (GGN)>23 carriers and one item was worse for short (GGN)<23 carriers. The AMS item for decrease in sexual desire or libido was worse for short (CAG)9–19 carriers than for medium (CAG)20–24 carriers. Through the ad hoc questionnaire, significant findings in (CAG)n and/or (GGN)n repeats were obtained for penile discomfort, loss of scrotal sensitivity, scrotal discomfort, less pubic hair, loss of perceived perineal fullness, increased sperm density, involuntary muscle spasms, loss of muscle tone, increased weight (>2 kg), increased skin dryness, and onset of symptoms after finasteride use.

Conclusion

This study showed that short and/or long (CAG)n and (GGN)n repeats had different frequencies according to symptoms reported by patients with PFS, likely reflecting the vast array of genes modulated by the AR. This study showed a U-curvilinear profile of (CAG)n repeats for skin dryness symptoms, where the two extremes exhibited a worse condition than medium repeats. Further studies are necessary to investigate the PFS pathophysiology using a precision medicine approach.

Androgen receptor GGC repeat might be more involved than CAG repeat in the regulation of the metabolic profile in men

The influence of androgen receptor (AR) GGC repeat polymorphism on the metabolic profile of men has been much less studied than the one of CAG tract polymorphism. Therefore, in this study, we looked for the association of GGC and CAG tract with cardiovascular risk factors in men. Ninety-eight men followed by our andrological unit were retrospectively reviewed. Clinical and biochemical parameters on cardiovascular risk were considered. AR CAG and GGC polymorphisms were studied. GGC triplets were found to be positively and significantly correlated with several cardiovascular risk factors. On the other hand, inverse and significant correlations of CAG triplets were found with insulin and HOMA. As expected, age was positively correlated with cardiovascular risk, whereas total testosterone was inversely correlated with metabolic profile. Estradiol was not found to be correlated with any of the metabolic parameters. In the total sample, multivariate linear regression analysis confirms the positive and independent association of GGC triplets with glycemia, glycated hemoglobin, total cholesterol, triglycerides and homeostasis model assessment of insulin resistance (HOMA), whereas CAG repeat length is negatively associated with insulin and HOMA. Such associations are also substantially confirmed in non-diabetic subjects, whereas in diabetic patients only the GGC tract seems to be involved in the metabolic profile regulation. Our work shows a relevant role for GGC repeat tract in conditioning male cardiovascular risk, thus rendering necessary a deeper analysis on the role of GGC polymorphism both from the molecular and the clinical point of view.

Genetic Association Between Androgen Receptor Gene CAG Repeat Length Polymorphism and Male Infertility: A Meta-Analysis

The association between polymorphism of androgen receptor gene CAG (AR-CAG) and male infertility in several studies was controversial. Based on studies on association between AR-CAG repeat length and male infertility in recent years, an updated meta-analysis is needed. We aimed to evaluate the association between AR-CAG repeat length and male infertility in advantage of the data in all published reports.We searched for reports published before August 2015 using PubMed, CNKI, VIP, and WanFang. Data on sample size, mean, and standard deviation (SD) of AR-CAG repeat length were extracted independently by 3 investigators.Forty-four reports were selected based on criteria. The overall infertile patients and azoospermic patients were found to have longer AR-CAG repeat length (standard mean difference (SMD) = 0.19, 95% confidence interval (CI): 0.10-0.28, P < 0.01; SMD = 0.36, 95% CI: 0.10-0.61, P < 0.01). AR-CAG repeat length was longer in infertile men in Asian, Caucasian, and mixed races (SMD = 0.25, 95% CI: 0.08-0.43, P <0.01; SMD = 0.13, 95% CI: 0.02-0.25, P <0.05; SMD = 0.39, 95% CI: 0.15-0.63, P <0.01). The overall study shows that increased AR-CAG repeat length was associated with male infertility. The subgroup study on races shows that increased AR-CAG repeat length was associated with male infertility in Asian, Caucasian, and mixed races. Increased AR-CAG repeat length was also associated with azoospermia.This meta-analysis supports that increased androgen receptor CAG length is capable of causing male infertility susceptibility.

Influence of Androgen Receptor Gene CAG and GGC Polymorphisms on Male Sexual Function: A Cross-Sectional Study

Background. No study has assessed the possible involvement of GGC androgen receptor (AR) polymorphism in sexual function. Our aim is to evaluate the association between CAG and GGC AR polymorphisms in this function. Methods. We retrospectively examined eighty-five outpatients. Clinical, biochemical, and genetic parameters were considered. Sexual assessment was performed using the International Index of Erectile Function (IIEF) which evaluates erectile function (EF), orgasmic function (OF), sexual desire (SD), intercourse satisfaction (IS), and overall satisfaction (OS). Results. In the whole sample, CAG repeats were inversely correlated with EF, OF, and total IIEF-15 score, whereas GGC tracts did not show any significant correlation with sexual function. CAG relationship with IIEF items retained significance only in the eugonadal but not in the hypogonadal cohort. On the other hand, GGC tracts were not found to be significantly correlated with IIEF variables in either eugonadal or hypogonadal subjects. In eugonadal subjects, logistic regression pointed out that a higher number of CAG triplets were associated with lower values of EF, OF, SD, OS, and total IIEF independently from other confounders. Conclusions. GGC polymorphism seems not to exert any influence on sexual function, whereas CAG polymorphism appears to affect sexual parameters only in eugonadal subjects.

Association of the polymorphism in the androgen receptor gene and endothelial function in men with type 2 diabetes

In recent years, actively studied the effect of androgen deficiency on the cardiovascular system, including endothelial function. Genomic effects of testosterone caused by the length of CAG repeats polymorphism in the androgen receptor (AR) gene.Aim. To examine the association of the polymorphism in the AR gene and carbohydrate, lipid metabolism, endothelial function in men with type 2 diabetes.Materials and methods. We examined 88 men, aged 40-65 years (mean age 53±6,4years) with type 2 diabetes. All patients underwent the study of carbohydrate and lipid metabolism, the assessment of vasomotor endothelial function of the brachial artery by ultrasound sonography, were studied biochemical markers of endothelial dysfunction – ICAM-1, VCAM-1, p-selectin, e-selectin, resistin and number of CAG-repeats in the AR gene. Statistical analysis was performed using the application package SPSS 21,0 using regression analysis.Results. The number of CAG repeats had a significant positive regression to the level of total testosterone, a weak negative regression of the number of CAG repeats in the AR gene and lipid metabolism: triglycerides, LDL, atherogenic index. The assessment of the brachial artery ultrasonography revealed negative regression of the baseline brachial artery diameter and blood flow velocity in the endothelium-dependent vasodilation. The number of CAG repeats was significantly correlated with the levels of p-selectin and resistin. Thus, increasing the number of CAG repeats in the AR gene via a weakening of sensitivity to androgens leads to disruption of endothelial function in men with type 2 diabetes. Increasing the number of CAG repeats in the AR gene leads to deterioration of linear flow velocity during the test with reactive hyperemia with increasing production of p-selectin and resistin.Conclusions. The number of CAG repeats in the AR gene can be regarded as a predictor of the development and progression of cardiovascular lesions in men with type 2 diabetes.

Influence of androgen receptor CAG polymorphism on sexual function recovery after testosterone therapy in late-onset hypogonadism

INTRODUCTION

Androgen receptor (AR) CAG polymorphism has been found to influence sexual function. However, no study has evaluated its potential to condition sexual function recovery after testosterone replacement therapy (TRT) in a large cohort of hypogonadic subjects.

AIM

To evaluate the role of this polymorphism in sexual function improvement after TRT in late-onset hypogonadism (LOH).

METHODS

Seventy-three men affected by LOH were retrospectively considered. Evaluations were performed before TRT started (time 0) and before the sixth undecanoate testosterone injection.

MAIN OUTCOME MEASURES

International Index of Erectile Function (IIEF) questionnaire (erectile function [EF], orgasmic function [OF], sexual desire [SD], intercourse satisfaction [IS], overall satisfaction [OS], and total IIEF-15 score); total and free testosterone and estradiol; AR gene CAG repeat number.

RESULTS

TRT induced a significant increase in total and free testosterone and estradiol. All IIEF domains significantly improved after TRT. AR CAG repeats negatively and significantly correlated with all the variations (Δ-) of sexual function domains, except for Δ-OS. Conversely, Δ-total testosterone was found to be positively and significantly correlated with sexual function domain variations, except for Δ-IS and Δ-OS. Δ-estradiol did not correlate significantly with any of the variations of sexual function domains. After inclusion in generalized linear models, the number of AR gene CAG triplets was found to be independently and negatively associated with Δ-EF, Δ-SD, Δ-IS, and Δ-Total IIEF-15 score, whereas Δ-total testosterone was independently and positively associated with Δ-EF, Δ-OF, Δ-SD, and Δ-Total IIEF-15 score. However, after including time 0 total testosterone in the model, AR gene CAG triplets remained independently and negatively associated only with Δ-EF and Δ-Total IIEF-15 score, whereas Δ-total testosterone was independently and positively associated only with Δ-EF.

CONCLUSIONS

Longer length of AR gene CAG repeat tract seems to lower TRT-induced improvement of sexual function in LOH.