Preliminary study of letrozole use for improving spermatogenesis in non-obstructive azoospermia patients with normal serum FSH

Effect of a single dose of letrozole on ejaculation time, semen quality, and testicular hemodynamics in goat bucks subjected to heat stress

Letrozole (LTZ) is an aromatase inhibitor that limits estrogen (E2) production and increases testosterone (T) levels. This research aimed to examine the impact of a single dose of LTZ on testicular hemodynamics, ejaculation time, and semen quality in goats under heat stress (HS). Therefore, Doppler examination and semen evaluation were performed on twelve mature bucks for two weeks (W-1, W-2) as pre-heat stress control during winter. Then during summer HS bucks were subjected to Doppler examination, semen evaluation, and hormonal analysis (T, E2, and LH) at 0 h. Afterward, bucks were assigned into two groups and subcutaneously injected with physiological saline (n = 6; CON) or LTZ (0.25 mg/kg BW; n = 6; LTZ). Both groups were subjected to Doppler scanning and hormonal analysis at 2, 4, 24, 48, 72, 96,144, and 168 h. Semen evaluation was performed at 48 and 168 h. The LTZ group showed increasing (P < 0.05) in semen volume, sperm motility, and viability and decreasing (P < 0.05) in ejaculation time and sperm abnormalities compared to CON group at 48 h. Additionally, T concentrations increased (P < 0.01) at 2, 24, and 48 h, E2 decreased (P < 0.01) from 2 to 48 h, and LH raised (P < 0.01) at 2 and 72 h in LTZ group compared to CON one. Doppler indices reduced (P < 0.05) at 96 h in LTZ group. semen pH and scrotal circumference were not affected by LTZ. In conclusion, LTZ administration shortened ejaculation time and enhanced semen quality in bucks during HS.

Impact of coenzyme Q10 as an adjuvant therapy to letrozole on spermiogram results and sex hormone levels in Iraqi men with infertility; randomized open label comparative study

Background: Worldwide, infertility affects about 15% of reproductive-age couples. In many cases, infertility can't be treated, however new treatment options with promising value have been involved in recent clinical trials. The aim of this clinical trial was to evaluate the impacts of adding coenzyme Q10 (CoQ10) to letrozole on the results of spermiogram and sex hormone tests in men diagnosed with idiopathic oligoasthenoteratozoospermia (iOAT) syndrome, which is a type of male defective spermatogenesis of unknown etiology. Methods: This randomized, open-label, parallel two-arm interventional study included 67 adult male patients aged 18-60 years with a confirmed diagnosis of iOAT syndrome recruited from The High Institute for Infertility Diagnosis & Assisted Reproduction Technologies/Nahrain University. Patients were randomly separated into two groups, Group A included 29 patients treated with letrozole 2.5 mg tablet orally twice a week, Group B included 38 patients treated with a combination of letrozole 2.5 mg tablet orally twice a week plus CoQ10 400 mg per day. Both groups completed treatment for three months. Semen samples, serum follicle-stimulating hormone (FSH), estradiol (E 2), and testosterone (T) were analyzed at day one, and at the end of month one, two and three. Results: Both groups showed that sperm concentration, normal morphology, total sperm count and motility, serum testosterone and FSH levels, and T/E 2 ratio were significantly increased, while estradiol levels significantly decreased after three months of treatment. Seminal fluid volume changed significantly in group A only. In comparing between the two groups, all measured parameters, apart from sperm motility and FSH level, demonstrated a significant difference after three months of treatment, while sperm volume reached significant value after only two months of therapy. Conclusions: CoQ10 as adjuvant treatment to letrozole effectively improved most of the tested sperm parameters in Iraqi men with iOAT. Registration: ClinicalTrials.gov ( NCT05847257, May 6, 2023).

[Medical treatments for male infertility]

BACKGROUND

Treatments to stimulate spermatogenesis and antioxidant food supplements are often offered to infertile patients either before sperm extraction surgery to improve results, or as part of medically assisted reproduction or spontaneous fertility to increase the likelihood of a live birth.

METHODS

A bibliographic search limited to English-language literature on men published before 5/2023 was carried out, including clinical trials, literature reviews and meta-analyses on spermatogenesis-stimulating molecules and antioxidant treatments.

RESULTS

Several medical treatments seem capable of improving male fertility: they act mainly by stimulating spermatogenesis through hormones, or by reducing the effects of oxidative stress. With regard to oligoasthenozoospermia, the literature shows that certain hormonal treatments stimulating spermatogenesis are useful. In the case of non-obstructive azoospermia, the value of treatment depends on the patient's FSH and testosterone levels. AOX supplementation appears to improve certain spermogram parameters and have an impact on pregnancy and live birth rates.

CONCLUSION

This review should help urologists gain a better understanding of the various medical treatments and enable them to define an appropriate therapeutic strategy, tailored to the patient and the couple, in order to obtain the best results.

The use of hormone stimulation in male infertility

Infertility affects 15% of couples worldwide and in approximately 50% of cases the cause is secondary to an abnormality of the sperm. However, treatment options for male infertility are limited and empirical use of hormone stimulation has been utilised. We review the contemporary data regarding the application of hormone stimulation to treat male infertility. There is strong evidence supporting the use of hormone stimulation in hypogonadotropic hypogonadism but there is inadequate evidence for all other indications.

A Review on the Use of Letrozole in Female and Male Infertility

Infertility in developing countries is a distinct and complex problem that disproportionately affects women. Though not a physically restraining disease, it causes a huge social burden on the emotional, financial, and psychosocial quotients of those who suffer from it. Assisted reproductive procedures are frequently used to treat infertility. Years ago, the emergence of ovulation induction represented a significant advancement in treating female infertility. Letrozole, an aromatase inhibitor, is a potential therapy for ovulation induction. Numerous clinical conditions, including anovulatory infertility, polycystic ovarian syndrome, unexplained infertility, and early stages of endometriosis-related infertility, as well as many with improved live birth rates, have been proven to benefit from letrozole treatment. Letrozole is a superior alternative to the widely utilized ovulation induction with clomiphene citrate. While clomiphene citrate has certain limitations, letrozole successfully overcomes these limitations because of its lack of prolonged anti-estrogenic activity, short half-life, and lack of estrogen receptor activation. In most cases, this results in mono-follicular development and excellent live birth rates. According to the most recent research, letrozole can be used as the first-line therapy to treat infertility caused by polycystic ovarian syndrome and other causes. Letrozole is also emerging as a possible treatment for male infertility of unknown cause, proving to be an effective way of influencing hormonal profiles and increasing various seminal parameters such as sperm motility and concentration, as it inhibits aromatization affecting the feedback mechanism to the hypothalamus. This review focuses on our current knowledge of the uses of letrozole for female and male infertility, its mechanisms, and its benefits.

Efficacy and safety of letrozole or anastrozole in the treatment of male infertility with low testosterone-estradiol ratio: a meta-analysis and systematic review

BACKGROUND

Aromatase inhibitors (AIs) have been used to treat male infertility for decades. However, due to the lack of large-scale randomized controlled studies and basic research, the efficacy and safety of AIs in the treatment of male infertility remain controversial. Therefore, it is necessary to conduct an evidence-based preliminary evaluation of the existing clinical trials of AIs in the treatment of male infertility.

METHOD

A comprehensive literature search were performed in PubMed, Embase, Cochrane, CNKI, VIP, CBM, and Wanfang databases through August 2021 for all studies. We conducted a systematic review with meta-analysis of the all available studies reporting sperm conventional parameters, gonadotropin and testosterone levels, and/or the pregnancy rate.

RESULTS

A total of 10 studies involving 666 patients were included. letrozole (LE) or anastrozole (AZ) administration increased significantly sperm concentration, total sperm count, and serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) levels and testosterone to estradiol ratio (T/E2), but E2 levels were significantly reduced compared with baseline values. Compared with the control group, which included selective estrogen receptor modulators (SEMRs) or HCG, LE or AZ did not have any significant effect on sperm concentration, motility and morphology, except that AIs had less effect on sperm motility than the control group (WMD: -2.55; 95% CI:-4.11 to-1.00; P = 0.001).

CONCLUSION

AIs may be effective in the treatment of male infertility. For male infertile patients planning assisted reproduction, discontinuation of AIs for 2-7 days prior to sperm retrieval may increase the success rate of fertilization. Further studies with larger sample sizes are needed to validate these findings. This article is protected by copyright. All rights reserved.

Effect of Letrozole Administration as a Selective Aromatase Inhibitor on Male Rat's Reproductive Performance

This study was designed to investigate the effect of administrating a selective aromatase inhibitor, letrozole, on the parameters of the rat's sperm and testicular histomorphology. A total of 40 male Wistar rats with an age of about 5 months old and an average weight of 190±10 g were divided randomly into 4 groups (n=10 each) and treated for 6 weeks. The first group (C) was given normal saline only as a control group. The second (T1), third (T2), and fourth (T3) groups received doses of 0.5, 1, and 1.5 mg/animal letrozole, respectively. At the end of the experiment (42 days), all animals were euthanized and the samples were obtained for more evolutions. The results of this study showed a significant increase in sperms quality (P-value≤0.05) while indicating a significant decrease in sperm abnormality in the T1 group, compared to the C group. Moreover, there was a significant difference represented by an increase in sperm quality, and a significant difference represented by a decrease in sperms abnormality in the T2 group, compared to the C group. On the other hand, there was a significant difference represented by an increase in sperm quality, and a significant difference represented by a decrease in sperm abnormality in the T3 group, compared to the T2 group. Normal somniferous tubules with high spermatoscopy counts were shown in histologic sections in the control group, primary and secondary spermatocytes with spermatozoa. In the T1 group, there was adequate spermatogenesis with a thick basement membrane. In the T2 group, there was normal testicular tissue with a significant increase in spermatogenic activity and number. In the T3 group, there was no significant atrophy or other pathology. The results of the current study suggested that letrozole improved spermatogenesis while causing no visible pathological alterations in testis tissue.

OUP accepted manuscript

BACKGROUND

The beneficial effects of hormonal therapy in stimulating spermatogenesis in patients with non-obstructive azoospermia (NOA) and either normal gonadotrophins or hypergonadotropic hypogonadism prior to surgical sperm retrieval (SSR) is controversial. Although the European Association of Urology guidelines state that hormone stimulation is not recommended in routine clinical practice, a significant number of patients undergo empiric therapy prior to SSR. The success rate for SSR from microdissection testicular sperm extraction is only 40–60%, thus hormonal therapy could prove to be an effective adjunctive therapy to increase SSR rates.

OBJECTIVE AND RATIONALE

The primary aim of this systematic review and meta-analysis was to compare the SSR rates in men with NOA (excluding those with hypogonadotropic hypogonadism) receiving hormone therapy compared to placebo or no treatment. The secondary objective was to compare the effects of hormonal therapy in normogonadotropic and hypergonadotropic NOA men.

SEARCH METHODS

A literature search was performed using the Medline, Embase, Web of Science and Clinicaltrials.gov databases from 01 January 1946 to 17 September 2020. We included all studies where hormone status was confirmed. We excluded non-English language and animal studies. Heterogeneity was calculated using I² statistics and risk of bias was assessed using Cochrane tools. We performed a meta-analysis on all the eligible controlled trials to determine whether hormone stimulation (irrespective of class) improved SSR rates and also whether this was affected by baseline hormone status (hypergonadotropic versus normogonadotropic NOA men). Sensitivity analyses were performed when indicated.

OUTCOMES

A total of 3846 studies were screened and 22 studies were included with 1706 participants. A higher SSR rate in subjects pre-treated with hormonal therapy was observed (odds ratio (OR) 1.96, 95% CI: 1.08–3.56, P = 0.03) and this trend persisted when excluding a study containing only men with Klinefelter syndrome (OR 1.90, 95% CI: 1.03–3.51, P = 0.04). However, the subgroup analysis of baseline hormone status demonstrated a significant improvement only in normogonadotropic men (OR 2.13, 95% CI: 1.10–4.14, P = 0.02) and not in hypergonadotropic patients (OR 1.73, 95% CI: 0.44–6.77, P = 0.43). The literature was at moderate or severe risk of bias.

WIDER IMPLICATIONS

This meta-analysis demonstrates that hormone therapy is not associated with improved SSR rates in hypergonadotropic hypogonadism. While hormone therapy improved SSR rates in eugonadal men with NOA, the quality of evidence was low with a moderate to high risk of bias. Therefore, hormone therapy should not be routinely used in men with NOA prior to SSR and large scale, prospective randomized controlled trials are needed to validate the meta-analysis findings.

Clinical application of aromatase inhibitors to treat male infertility

BACKGROUND

Infertility affects 15% of men and contributes to nearly half of all cases of infertility. Infertile men usually have impaired spermatogenesis, presenting as azoospermia or various degrees of asthenospermia and oligozoospermia. Spermatogenesis is a complex and coordinated process, which is under precise modulation by the hypothalamic-pituitary-gonadal (HPG) axis. An aberrant hormone profile, especially an imbalance between testosterone (T) and estradiol (E2), plays an essential role in male infertility. In the male, E2 is produced mainly from the conversion of T by the aromatase enzyme. Theoretically, reducing an abnormally elevated T:E2 ratio using aromatase inhibitors (AIs) could restore the balance between T and E2 and optimize the HPG axis to support spermatogenesis. For decades, AIs have been used to treat male infertility empirically. However, owing to the lack of large-scale randomized controlled studies and basic research, the treatment efficacy and safety of AIs in male infertility remain controversial. Therefore, there is a need to summarize the clinical trials and relevant basic research on the application of AIs in the treatment of male infertility.

OBJECTIVE AND RATIONALE

In this narrative review, we summarized the application of AIs in the treatment of male infertility, including the pharmacological mechanisms involved, clinical trials focused on patients with different types of infertility, factors affecting treatment efficacy and the side-effects.

SEARCH METHODS

A literature search was performed using MEDLINE/PubMed and EMBASE, focusing on publications in the past four decades concerning the use of AIs for treating male infertility. The search terms included AI, male infertility, letrozole, anastrozole, testolactone, azoospermia, oligozoospermia, aromatase polymorphisms, obesity and antiestrogens, in various combinations.

OUTCOMES

Clinical studies demonstrate that AIs, especially nonsteroidal letrozole and anastrozole, could significantly inhibit the production of E2 and its negative feedback on the HPG axis, resulting in increased T and FSH production as well as improved semen parameters in infertile men. Large-scale surveys suggest that obesity may result in symptoms of hypogonadism in both fertile and infertile males, such as decreased semen quality and attenuated sexual function, which can be improved by AIs treatment. Polymorphisms of the aromatase gene CYP19A1, including single nucleotide polymorphisms and tetranucleotide TTTA repeats polymorphism (TTTAn), also influence hormone profiles, semen quality and treatment efficacy of AIs in male hypogonadotropic hypogonadism and infertility. The side-effects of AIs in treating male infertility are various, but most are mild and well tolerated.

WIDER IMPLICATIONS

The application of AIs in treating male infertility has been off-label and empirical for decades. This narrative review has summarized the target patients, dose, treatment duration and side-effects of AIs. Polymorphisms of CYP19A1 that may affect AIs treatment efficacy were also summarized, but a full understanding of the mechanisms involved in AIs action requires further study.

[Testicular sperm extraction in male infertility : Indications, success rates, practical implementation, and possible complications]

BACKGROUND

Unwanted childlessness is a burden on a couple's relationship. The therapeutic spectrum of male infertility has increased significantly in recent years so that even azoospermia patients can be given biological paternity by testicular sperm extraction (TESE).

OBJECTIVES

The indications, success rates, practical implementation, and possible complications of conventional and microscopic TESE in male infertility are presented in this review.

METHODS

A nonsystematic search of the relevant literature was carried out.

RESULTS

In obstructive azoospermia (OA), primarily desobstructive surgical procedures are used, while TESE is the surgical procedure of choice in nonobstructive azoospermia (NOA). In the latter, sperm extraction can be performed conventionally or microscopically (mTESE) assisted, whereby the latter offers an advantage in terms of sperm detection rate in the case of small testicular volumes (<12 ml), chemotherapy, Klinefelter's disease and AZFc microdeletions. The sperm detection rate of TESE is about 50%. Postoperative controls are useful because of the possible induction of symptomatic hypogonadism.

CONCLUSION

Before performing TESE, determining the hormone status and human genetic clarification are necessary. Any costs incurred and the possibility of missing sperm proof must be discussed. Close cooperation between andrologists, gynecologists, reproductive physicians, and human geneticists is necessary. All in all, TESE is a safe surgical procedure with a low complication rate.

Effect of Letrozole on sperm parameters, chromatin status and ROS level in idiopathic Oligo/Astheno/Teratozoospermia

BACKGROUND

This study investigates the effect of letrozole on hormone profiles, semen parameters, body mass index (BMI), degree of oxidative stress and sperm chromatin integrity in men with idiopathic oligo/astheno/teratozoospermia (iOAT) and T:E₂ ratio ≤ 10.

MATERIALS AND METHODS

This study is a longitudinal, prospective, interventional and open-labelled clinical trial. Semen samples were collected from 20 iOAT men with low serum testosterone (T) to estradiol (E₂) ratio (T:E₂ ratio ≤ 10). The participants were treated with 2.5 mg letrozole orally per day for 3 months. Then, sperm parameters, hormone profiles, BMI, chromatin integrity and intracellular reactive oxygen species (ROS) level were assessed pre- and post- treatment. The chromatin integrity was evaluated by assessment of DNA fragmentation (with TUNEL assay) and protamine deficiency (with Chromomycin A3, CMA3). Also, the intracellular ROS levels were investigated by 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Finally, the differences between the parameters evaluated before and after letrozole treatment were analyzed with the t-test and the Wilcoxon signed-rank test.

RESULTS

Sperm concentration, percentage of sperm motility and its normal morphology increased significantly after letrozole treatment. Moreover, serum testosterone level increased but estradiol level decreased significantly following treatment. The mean of T:E2 ratio improved 1600%. Also, letrozole treatment significantly reduced the percentage of sperm TUNEL positivity and sperm CMA3 positivity. While no significant difference was observed between intracellular ROS levels and BMI before and after treatment. Finally, as a notable result, four spontaneous pregnancies (20%) were achieved after treatment.

CONCLUSIONS

Letrozole treatment can effectively increase spontaneous pregnancies by improving sperm parameters and sperm chromatin integrity in men with iOAT and T:E2 ratio ≤ 10.

TRIAL REGISTRATION

Trial registration: IRCT, IRCT20191030045283N1. Registered 16 November 2019 - Retrospectively registered, https://fa.irct.ir/user/trial/43484/view.

Frontiers in hormone therapy for male infertility

For a significant number of couples worldwide, infertility is a harsh reality. As specialists in male infertility, much of our armamentarium lacks definitive, evidence-based therapies. For years, we have relied on manipulation of the male hormonal axis to treat those men who help carry the burden of infertility in their partnerships. Indeed, male factor infertility is the sole component of infertility in at least 20% of couples. Further compounding this dilemma is that 25% to 50% of males with infertility have no identifiable etiology and thus present a true management conundrum. This manuscript is an attempt to clarify what therapies exist for the treatment of male factor infertility. We have reviewed the relevant infertility literature honing, our focus on hormonal anomalies and their subsequent impact on fertility. Many of the therapies discussed have been utilized in practice for generations. Thus, this article attempts to provide the evidence-based literature to support the continued use of the current treatment paradigm. Furthermore, we recognize that any review beckons a discussion of what challenges and therapies await on the horizon. For instance, there has been significant interest in restoring spermatogenesis after testosterone replacement therapy (TRT). We explore the adverse long-term spermatogenic outcomes associated with TRT, which with the widespread use of TRT, will inevitably present a great challenge for male infertility specialists. Moreover, we discuss the role of varicocelectomy in the treatment of hypogonadism and infertility, review the association between growth hormone (GH) and male fertility and address the challenges presented by the rising prevalence of obesity.

Association of the VDAC3 gene polymorphism with sperm count in Han-Chinese population with idiopathic male infertility

Voltage-dependent anion channel (VDAC) is a multifunctional channel protein across the outer mitochondrial membrane of somatic cells and participates in many physiological and pathophysiological processes. Up to now, only a few studies, including our previous studies, showed that VDAC exists in mammalian spermatozoa and is involved in spermatogenesis and sperm functions. There is no report about VDAC genetic variants in germinal tissues or cells. To investigate the possible association between VDAC genetic variants and human sperm quality, we performed semen analysis and variant Genotyping of VDAC3 subtype (rs7004637, rs16891278 and rs6773) of 523 Han-Chinese males with idiopathic infertility respectively by computer assisted semen analysis (CASA) and single nucleotide polymorphism (SNP) Genotyping assay. No significant association was found between rs7004637 and rs6773 genotypes and semen quality. However, the AG genotype of rs16891278 showed a significantly lower sperm concentration compared with the AA genotype (P = 0.044). Our findings suggest that VDAC3 genetic variants may be associated with human sperm count.

Outcomes of anastrozole in oligozoospermic hypoandrogenic subfertile men

OBJECTIVE

To determine whether the change in sperm parameters in subfertile hypoandrogenic men treated with anastrozole is correlated to the magnitude of increase in testosterone (T) to estrogen ratio in men responding to treatment.

DESIGN

Retrospective study.

SETTING

Male fertility clinic.

PATIENT(S)

The study group consisted of 86 subfertile hypoandrogenic men with low T/estradiol (E₂) ratio (n = 78) or a prior aversive reaction to clomiphene citrate (n = 8).

INTERVENTION(S)

All patients were treated with 1 mg anastrozole daily, administered orally.

MAIN OUTCOME MEASURE(S)

Hormone analysis and semen analysis before and after treatment were performed. Hormone analysis included measurements of total T, E₂, sex-hormone binding globulin, albumin, FSH, and LH, and bioavailable T was calculated. Total motile sperm count was calculated from the semen analysis.

RESULT(S)

In all, 95.3% of patients had an increased serum T and decreased serum E₂ after treatment with anastrozole. Sperm concentration and total motile counts improved in 18 of 21 subfertile hypoandrogenic oligozoospermic men treated with anastrozole. In these men the magnitude of total motile count increase was significantly correlated with the change in the T/E₂ ratio. No improvement was seen in semen parameters of men with azoospermia, cryptozoospermia, or normozoospermia at presentation.

CONCLUSION(S)

Approximately 95% of men with hypoandrogenism responded with improved endocrine parameters, and a subset of oligozoospermic men (approximately 25% of all patients) displayed significantly improved sperm parameters. In that subset, increase in sperm parameters was correlated with the change in the T/E₂ ratio, which argues for a physiologic effect of treatment.

The frequency of follicle stimulating hormone receptor gene polymorphisms in Iranian infertile men with azoospermia

BACKGROUND

Azoospermia is the medical condition of a man not having any measurable level of sperm in his semen. Follicle stimulating hormone (FSH) is a member of the glycoprotein hormone family that plays an important role in human reproduction because of its essential role in normal spermatogenesis. Various Single Nucleotide Polymorphisms (SNPs) have been reported within FSH receptor (FSHR) gene that may affect the receptor function.

OBJECTIVE

The present study aimed to investigate the correlation between two FSHR SNPs at positions A919G, A2039G, and susceptibility to azoospermia in a group of Iranian azoospermic men. The association between FSH levels within the sera and A919G and A2039G alleles and genotypes were also investigated.

MATERIALS AND METHODS

This case control study was performed on 212 men with azoospermia (126 non-obstructive and 86 obstructive) and 200 healthy Iranian men. Two FSHR gene SNPs were genotyped using PCR-RFLP method. The relationship between FSH levels within the sera and A919G and A2039G alleles and genotypes were also investigated.

RESULTS

Statistical analysis indicated that at A919G position, AA genotype and A allele were more frequent in obstructive azoospermia cases compared to non-obstructive or normal men (p=0.001). Regarding A2039G polymorphisms, no significant difference was observed between both azoospermia groups and the controls. The mean level of serum FSH was higher in the non-obstructive men compared to the obstructive patients (23.8 versus 13.8, respectively, p= 0.04).

CONCLUSION

The results of the present study indicated that the genetic polymorphisms in the FSHR gene might increase the susceptibility to azoospermia in Iranian men.

[Medical optimisation of sperm retrieval in non obstructive azoospermia]

Medical optimisation of sperm retrieval in non-obstructive azoospermia is reviewed. Gonadotropin treatment of hypogonadotropic hypogonadism allows obtaining sperms in the ejaculate in about 90% of cases provided the duration of treatment was long enough. TESE is indicated in case of persistent azoospermia at 2 years of continuous treatment. Some publications reported a possible effect of hormonal treatments (FSH, hCG, anti-estrogens, aromatase inhibitors) in primary spermatogenic failure, but mainly in cases selected for their favourable histology and normal hormonal levels. The effect on unselected cases remains doubtful. Conversely, the effect of the treatment of varicoceles is significant. Other medical treatments or advises need further investigations.

Multivariate analysis to predict letrozole efficacy in improving sperm count of non-obstructive azoospermic and cryptozoospermic patients: a pilot study

We tested the hypothesis that letrozole increases sperm count in non-obstructive azoospermic or cryptozoospermic patients with a testosterone (T)/17-beta-2-oestradiol (E2) ratio <10. Forty-six patients with no chromosomal aberrations were randomized into two groups: 22 received letrozole 2.5 mg per day for 6 months (Group 1: 6 azoospermic + 16 cryptozoospermic patients), while 24 received a placebo (Group 2: 5 azoospermic + 19 cryptozoospermic patients). The following data were collected: two semen analyses, clinical history, scrotal Duplex scans, body mass index (BMI), Y microdeletion, karyotype and cystic fibrosis screens and follicle-stimulating hormone (FSH), luteinizing hormone (LH), E2, T and prolactin levels. Both before and after letrozole or placebo administration, the patients underwent two semen analyses and hormonal assessments. The differences were evaluated using the Mann-Whitney U test. The relationships between sperm concentration after letrozole administration with respect to FSH, T/E2 ratio, bilateral testicle volume and BMI before letrozole administration were assessed using multivariate analysis. The side effects were assessed using the chi-square test. Group 1 had sperm concentration (medians: 400-1.290 × 10(6) ml(-1); P<0.01) and motility (medians: class A from 2% to 15%; P<0.01), FSH, LH and T significantly increased, while Group 2 did not. E2 levels diminished significantly in Group 1, but not in Group 2. Eight patients in Group 1 demonstrated side effects, whereas no patient side effects were observed in Group 2. The sperm concentration after letrozole administration is inversely related to T/E2, FSH and BMI; a direct relationship emerged between sperm concentration and testicular volume.

Azoospermia due to spermatogenic failure

This article summarizes the current literature regarding azoospermia caused by spermatogenic failure. The causes and genetic contributions to spermatogenic failure are reviewed. Medical therapies including use of hormonal manipulation, whether guided by a specific abnormality or empiric, to induce spermatogenesis are discussed. The role of surgical therapy, including a discussion of varicocelectomy in men with spermatogenic failure, as well as an in-depth review of surgical sperm retrieval with testicular sperm extraction and microdissection testicular sperm extraction, is provided. Finally, future directions of treatment for men with spermatogenic failure are discussed, namely, stem cell and gene therapy.

Successful use of aromatase inhibitor letrozole in NOA with an elevated FSH level: a case report

Aromatase inhibitors inhibit the conversion of testosterone to oestrogens and could reduce serum oestradiol concentrations. Letrozole is one of aromatase inhibitors frequently used in treatment of men with oligospermia. We present the case of an infertile man with small testes and an elevated FSH level, which was diagnosed as NOA, hypospermatogenesis proven by testicular biopsy. After taking letrozole for 3 months, semen analyses by computer-aided sperm analysis present that this man had normal spermatogenesis. This is the first case report of the activation of spermatogenesis, in man who was NOA with elevated FSH level, resulting from the use of the one of aromatase inhibitors.

Microdissection testicular sperm extraction: an update

Patients with non-obstructive azoospermia (NOA) were once considered to be infertile with few treatment options due to the absence of sperm in the ejaculate. In the last two decades, the advent of intracytoplasmic sperm injection (ICSI), and the application of various testicular sperm retrieval techniques, including fine needle aspiration (FNA), conventional testicular sperm extraction (TESE) and microdissection testicular sperm extraction (micro-TESE) have revolutionized treatment in this group of men. Because most men with NOA will have isolated regions of spermatogenesis within the testis, studies have illustrated that sperm can be retrieved in most men with NOA, including Klinefelter's syndrome (KS), prior history of chemotherapy and cryptorchidism. Micro-TESE, when compared with conventional TESE has a higher sperm retrieval rate (SRR) with fewer postoperative complications and negative effects on testicular function. In this article, we will compare the efficacy of the different procedures of sperm extraction, discuss the medical treatment and the role of testosterone optimization in men with NOA and describe the micro-TESE surgical technique. Furthermore, we will update our overall experience to allow counseling on the prognosis of sperm retrieval for the specific subsets of NOA.

Aromatase inhibitors for male infertility

Some men with severely defective sperm production commonly have excess aromatase activity, reflected by low serum testosterone and relatively elevated estradiol levels. Aromatase inhibitors can increase endogenous testosterone production and serum testosterone levels. Treatment of infertile males with the aromatase inhibitors testolactone, anastrazole, and letrozole has been associated with increased sperm production and return of sperm to the ejaculate in men with non-obstructive azoospermia. Use of the aromatase inhibitors anastrazole (1 mg/day) and letrozole (2.5 mg/day) represent off-label use of these agents for impaired spermatogenesis in men with excess aromatase activity (abnormal testosterone/estradiol [T/E] ratios). Side effects have rarely been reported. Randomized controlled trials are needed to define the magnitude of benefit of aromatase inhibitor treatment for infertile men.