European Academy of Andrology guideline Management of oligo-astheno-teratozoospermia

Prospects for FSH Treatment of Male Infertility

CONTEXT

Despite the new opportunities provided by assisted reproductive technology (ART), male infertility treatment is far from being optimized. One possibility, based on pathophysiological evidence, is to stimulate spermatogenesis with gonadotropins.

EVIDENCE ACQUISITION

We conducted a comprehensive systematic PubMed literature review, up to January 2020, of studies evaluating the genetic basis of follicle-stimulating hormone (FSH) action, the role of FSH in spermatogenesis, and the effects of its administration in male infertility. Manuscripts evaluating the role of genetic polymorphisms and FSH administration in women undergoing ART were considered whenever relevant.

EVIDENCE SYNTHESIS

FSH treatment has been successfully used in hypogonadotropic hypogonadism, but with questionable results in idiopathic male infertility. A limitation of this approach is that treatment plans for male infertility have been borrowed from hypogonadism, without daring to overstimulate, as is done in women undergoing ART. FSH effectiveness depends not only on its serum levels, but also on individual genetic variants able to determine hormonal levels, activity, and receptor response. Single-nucleotide polymorphisms in the follicle-stimulating hormone subunit beta (FSHB) and follicle-stimulating hormone receptor (FSHR) genes have been described, with some of them affecting testicular volume and sperm output. The FSHR p.N680S and the FSHB -211G>T variants could be genetic markers to predict FSH response.

CONCLUSIONS

FSH may be helpful to increase sperm production in infertile men, even if the evidence to recommend the use of FSH in this setting is weak. Placebo-controlled clinical trials, considering the FSHB-FSHR haplotype, are needed to define the most effective dosage, the best treatment length, and the criteria to select candidate responder patients.

Follicle-Stimulating Hormone Treatment and Male Idiopathic Infertility: Effects on Sperm Parameters and Oxidative Stress Indices according to FSHR c. 2039 A/G and c. -29 G/A Genotypes

Scientific evidence shows that the administration of follicle-stimulating hormone (FSH) to infertile patients with normal serum FSH concentrations improves sperm parameters in oligozoospermic men. The aim of this study was to evaluate the effects of highly purified urofollitropin (hpFSH) on conventional and bio-functional sperm parameters and on oxidative stress indices in patients with idiopathic infertility. We also evaluated the response to hpFSH on these parameters in relationship to FSHR c. 2039 A/G and FSHR c. -29 G/A genotypes. A prospective longitudinal study was conducted on 42 patients with idiopathic male infertility, 23 of whom underwent to FSHR c. 2039 A/G and FSHR c. -29 G/A genotyping. Each patient was asked to collect two semen samples before and after administration of 150 IU hpFSH three times a week for 16 weeks. Patients were divided into responders or non-responders based on whether their total sperm count had at least doubled or was less than double at the end of treatment, respectively. Responders showed a significantly higher semen volume, sperm concentration, spermatids, and leukocytes. Non-responders had a significant decrease of the percentage of spermatozoa in early apoptosis after hpFSH administration. Oxidative stress indexes did not differ significantly after FSH administration in both groups. Conventional and bio-functional sperm parameters did not differ in patients with FSHR c. 2039 GG and AA genotypes, and FSHR c. -29 GG genotype both before and after FSH administration. The FSHR c. 2039 and FSHR -29 G/A genotypes and allelic distribution did not differ between responders and non-responders. FSH showed to be capable of ameliorating sperm parameters in about half patients treated, therefore it may be helpful in patients with idiopathic infertility.

Empiric therapy for idiopathic oligoasthenoteratozoospermia

Male infertility accounts for 50% of the causes of infertile couples, being more than 30% of unknown etiology. In these cases, empiric treatment can be an option prior to the application of assisted reproduction techniques. Empiric treatment can be categorized as hormonal, such as gonadotropins, antiestrogens and aromatase inhibitors, and antioxidant, with vitamins, trace elements and carnitine, among others. Although scientifically acceptable evidence is limited due to the absence of large randomized and controlled clinical trials, recent systematic reviews and meta-analyses show that treatment with gonadotropins, antiestrogens and antioxidants increases pregnancy and live birth rates and improves seminal parameters. Empiric medical treatment for idiopathic infertility can be considered in specific cases in order to improve semen quality and spontaneous fertility.

Infertility: Practical Clinical Issues for Routine Investigation of the Male Partner

About one-fifth of couples has fertility problems in Western countries. Male factors are present in about half of them, either alone or in combination with female causes. Therefore, both partners should be evaluated simultaneously. The fertility status and/or specific conditions of each partner influence the clinical and treatment approach. This article summarizes in a practical way when, how, and why the male partner of an infertile couple should be investigated. The available evidence and international guidelines were used, interpreting, discussing, and expanding them from personal decades-long experience in this field. The aim is to delineate the most appropriate clinical approach for the male partner of infertile couples, considering traditional and emerging technologies and laboratory analyses in the context of their clinical significance. Components of the initial evaluation in men without known risk factors for infertility should include at minimum medical history, physical examination, and semen analysis. Semen microbiological examination, endocrine assessment, scrotal ultrasound, and transrectal ultrasound are suggested in most men and are mandatory when specific risk factors for male infertility are known to be present or when the initial screening demonstrated abnormalities. Full examination, including genetic tests, testicular histology, or additional tests on sperm, is clinically oriented and/or suggested after the results of initial investigations.

Positive effect of nutraceuticals on sperm DNA damage in selected infertile patients with idiopathic high sperm DNA fragmentation

BACKGROUND

The use of nutraceuticals to improve sperm parameters and male fertility is debatable, even if evidence suggests that selected infertile patients might benefit from their use. In particular, oxidative stress might play a role in idiopathic male infertility, leading to sperm membrane damage and high sperm DNA fragmentation (SDF). The aim of this study was to evaluate, in selected idiopathic infertile men with high SDF, the effect on sperm DNA damage and on standard semen parameters of a nutraceutical formulation containing myoinositol, alpha lipoic acid, coenzyme Q10, selenium, zinc and B vitamins.

METHODS

The study included 60 idiopathic infertile men with DNA fragmentation index (DFI) >20%. Semen analysis and DFI determination were assessed at baseline and after three months of nutraceutical treatment. Primary outcome was change in DFI.

RESULTS

Semen volume, sperm concentration, total sperm count, sperm motility and sperm morphology did not change after treatment. Instead, sperm vitality significantly increased (65.9±11.8% pre-treatment vs. 69.4±9.4% post-treatment, P<0.05) and DFI significantly decreased (33.5±10.1% pre-treatment vs. 26.8±8.7% post-treatment, P=0.0001) after treatment. The percentage of men with normal standard sperm parameters significantly increased (15% vs. 30%, P<0.05). The mean decrease in DFI was -6.7±1.4% and the percentage of men with DFI ≤30% after treatment was 75.0% compared to 48.3% pre-treatment (P<0.005). Higher pre-treatment DFI (and no other parameters) correlated with greater DFI reduction after treatment.

CONCLUSIONS

Nutraceuticals might be effective in idiopathic infertile men with high DFI to reduce SDF, increase sperm vitality and globally improve semen parameters.

Follicle-stimulating Hormone (FSH) Action on Spermatogenesis: A Focus on Physiological and Therapeutic Roles

BACKGROUND

Human reproduction is regulated by the combined action of the follicle-stimulating hormone (FSH) and the luteinizing hormone (LH) on the gonads. Although FSH is largely used in female reproduction, in particular in women attending assisted reproductive techniques to stimulate multi-follicular growth, its efficacy in men with idiopathic infertility is not clearly demonstrated. Indeed, whether FSH administration improves fertility in patients with hypogonadotropic hypogonadism, the therapeutic benefit in men presenting alterations in sperm production despite normal FSH serum levels is still unclear. In the present review, we evaluate the potential pharmacological benefits of FSH administration in clinical practice.

METHODS

This is a narrative review, describing the FSH physiological role in spermatogenesis and its potential therapeutic action in men.

RESULTS

The FSH role on male fertility is reviewed starting from the physiological control of spermatogenesis, throughout its mechanism of action in Sertoli cells, the genetic regulation of its action on spermatogenesis, until the therapeutic options available to improve sperm production.

CONCLUSION

FSH administration in infertile men has potential benefits, although its action should be considered by evaluating its synergic action with testosterone, and well-controlled, powerful trials are required. Prospective studies and new compounds could be developed in the near future.

Development of a novel next-generation sequencing panel for diagnosis of quantitative spermatogenic impairment

PURPOSE

To develop and assess a novel custom next-generation sequencing (NGS) panel for male infertility genetic diagnosis.

METHODS

A total of 241 subjects with diagnosis of idiopathic infertility ranging from azoospermia to normozoospermia were sequenced by a custom NGS panel including AR, FSHB, FSHR, KLHL10, NR5A1, NANOS1, SEPT12, SYCP3, TEX11 genes. Variants with minor allele frequency < 1% were confirmed by Sanger sequencing.

RESULTS

Nineteen missense variants were detected in 23 subjects with abnormal sperm count, whilst no variants were identified in normozoospermic men. Of identified variants, we prioritized variants classified as pathogenic and of uncertain significance (VUS) (63.1%, 12/19). No missense variants were found in males with normal seminal parameters (0/67). Therefore, the prevalence of variants was significantly higher in patients with spermatogenic impairment (16/174 vs 0/67, p = 0.007).

CONCLUSION

This study confirms the utility to apply NGS panel for infertility diagnosis in order to find new genetic variants potentially linked to male infertility with much higher accuracy than standard tests suggested by guidelines. Indeed, based on biological significance, prevalence in the general population and clinical data of patients, it is plausible that identified variants in this study might be linked to quantitative spermatogenic impairment, although further studies are needed.

FSH for the Treatment of Male Infertility

Follicle-stimulating hormone (FSH) supports spermatogenesis acting via its receptor (FSHR), which activates trophic effects in gonadal Sertoli cells. These pathways are targeted by hormonal drugs used for clinical treatment of infertile men, mainly belonging to sub-groups defined as hypogonadotropic hypogonadism or idiopathic infertility. While, in the first case, fertility may be efficiently restored by specific treatments, such as pulsatile gonadotropin releasing hormone (GnRH) or choriogonadotropin (hCG) alone or in combination with FSH, less is known about the efficacy of FSH in supporting the treatment of male idiopathic infertility. This review focuses on the role of FSH in the clinical approach to male reproduction, addressing the state-of-the-art from the little data available and discussing the pharmacological evidence. New compounds, such as allosteric ligands, dually active, chimeric gonadotropins and immunoglobulins, may represent interesting avenues for future personalized, pharmacological approaches to male infertility.

European Academy of Andrology (EAA) guidelines on investigation, treatment and monitoring of functional hypogonadism in males: Endorsing organization: European Society of Endocrinology

BACKGROUND

Evidence regarding functional hypogonadism, previously referred to as 'late-onset' hypogonadism, has increased substantially during the last 10 year.

OBJECTIVE

To update the European Academy of Andrology (EAA) guidelines on functional hypogonadism.

METHODS

Expert group of academicians appointed by the EAA generated a series of consensus recommendations according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

RESULTS

The diagnosis of functional hypogonadism should be based on both the presence of clinical symptoms supported by repeatedly low morning fasting serum total testosterone (T) measured with a well-validated assay, after exclusion of organic causes of hypogonadism. Lifestyle changes and weight reduction should be the first approach in all overweight and obese men. Whenever possible, withdrawal/modification of drugs potentially interfering with T production should be advised. Testosterone replacement therapy (TRT) is contraindicated in men with untreated prostate or breast cancer, as well as severe heart failure. Severe low urinary tract symptoms and haematocrit >48%-50% represent relative contraindications for TRT. Prostate-specific antigen and digital rectal examination of the prostate should be undertaken in men >40 years of age before initiating TRT to exclude occult prostate cancer. Transdermal T should be preferred for initiation of TRT, whereas gonadotrophin therapy is only recommended when fertility is desired in men with secondary hypogonadism. TRT is able to improve sexual function in hypogonadal men. Other potential positive outcomes of TRT remain uncertain and controversial.

CONCLUSION

TRT can reliably improve global sexual function in men with hypogonadism in the short term. Long-term clinical benefits, and safety of TRT in functional hypogonadism, remain to be fully documented. Clinicians should therefore explicitly discuss the uncertainties and benefits of TRT and engage them in shared management decision-making.

From Spermiogram to Bio-Functional Sperm Parameters: When and Why Request Them?

The aim of this experimental study was to evaluate whether infertile patients may benefit from the evaluation of bio-functional sperm parameters in addition to the conventional semen analysis. To accomplish this, we evaluated the correlation between conventional and bio-functional sperm parameters based on their percentile distribution in search of a potential threshold of these latter that associates with conventional sperm parameter abnormalities. The study was conducted on 577 unselected patients with infertility lasting at least 12 months. We identified cut-off values according to the median of the population for mitochondrial membrane potential (MMP), number of alive spermatozoa, and chromatin abnormality. High MMP (HMMP) (≥46.25%) was associated with sperm concentration, sperm count, progressive motility, and normal form. Low MMP (LMMP) (≥36.5%) was found to be associated with semen volume, sperm concentration, total sperm count, progressive motility, total motility, and normal form. The number of alive spermatozoa (≥71.7%) was associated with sperm concentration and progressive motility whereas abnormal chromatin compactness (≥21.10%) was associated with sperm concentration, total sperm count, and progressive motility. The data would suggest that, for every increase in the percentile category of sperm concentration, the risk of finding an HMMP≤46.25 is reduced by 0.4 and by 0.66 for a total sperm count. This risk is also reduced by 0.60 for every increase in the percentile category of sperm progressive motility and by 0.71 for total sperm motility. Each increment of percentile category of the following sperm parameter was followed by a decrease in the risk of finding an LMMP≤36.5: sperm concentration 1.66, total sperm count 1.28, sperm progressive motility 1.27, total sperm motility 1.76, and normal form 1.73. Lastly, the data showed that, for every increase in the percentile category of total sperm count, the risk of finding an abnormal chromatin compactness ≤21.10 is reduced by 1.25 (1.04–1.51, p < 0.05) and an increase of total sperm motility is associated with a reduced risk by 1.44 (1.12–1.85, p < 0.05). Results suggest a correlation between bio-functional and conventional sperm parameters that impact the sperm fertilizing potential. Therefore, the evaluation of bio-functional sperm parameters by flow cytometry may be useful to explain some cases of idiopathic male infertility.

Use of follicle-stimulating hormone for the male partner of idiopathic infertile couples in Italy: Results from a multicentre, observational, clinical practice survey

BACKGROUND

The management of male idiopathic infertility is heterogeneous. Although meta-analyses reported the effectiveness on pregnancy rate, the real clinical impact of follicle-stimulating hormone (FSH) was not evaluated so far. In Italy, FSH is approved by the National Medicines Agency (AIFA) for idiopathic infertile patients with FSH < 8 IU/L, independently of semen parameters.

AIM

Primary endpoint was to record the therapeutic approach to the male partner of infertile couples. Secondary aim was to assess changes of semen parameters during FSH treatment.

METHODS

A multicentre, prospective, observational, clinical practice survey was carried out, enrolling the male partner of infertile couples attending ten Italian participating centres. Inclusion criteria were as follows: couple infertility, age >18 years and FSH serum levels <8 IU/L. Thus, all men in which AIFA allowed the FSH prescription were enrolled. Primary endpoint was the number of infertile patients treated with FSH. Secondary outcomes were semen parameters. The treating physician decided whether to offer FSH therapy and whether to re-evaluate the male partner.

RESULTS

A total of 718 infertile couples were enrolled, and 241 patients were re-evaluated (median follow-up: 4.5 months). In 64.9% (466 patients), a treatment was prescribed. FSH was prescribed in 397 patients (85.2% of treated men). Sperm concentration (P = .002) and normal form percentage (P < .001) significantly improved during FSH administration. No correlation was found between these parameters and FSH duration (P = .545 and P = .627, respectively) or dosage (P = .455 and P = .533, respectively). Among patients treated with FSH, the incidence of oligozoospermia decreased from 73.0% to 56.0% (P < .001) and teratozoospermia from 43.6% to 27.7% (P < .001).

DISCUSSION

This first nation-wide survey reveals a FSH prescription rate of 55% in patients qualifying for treatment according to AIFA. Although the study was not designed to highlight FSH efficacy in male infertility, a slight increase in semen parameters was demonstrated in about half of the treated men without adverse events.

The current status and future of andrology: A consensus report from the Cairo workshop group

BACKGROUND

In attempting to formulate potential WHO guidelines for the diagnosis of male infertility, the Evidence Synthesis Group noted a paucity of high-quality data on which to base key recommendations. As a result, a number of authors suggested that key areas of research/evidence gaps should be identified, so that appropriate funding and policy actions could be undertaken to help address key questions.

OBJECTIVES

The overall objective of this Consensus workshop was to clarify current knowledge and deficits in clinical laboratory andrology, so that clear paths for future development could be navigated.

MATERIALS AND METHODS

Following a detailed literature review, each author, prior to the face-to-face meeting, prepared a summary of their topic and submitted a PowerPoint presentation. The topics covered were (a) Diagnostic testing in male fertility and infertility, (b) Male fertility/infertility in the modern world, (c) Clinical management of male infertility, and (d) The overuse of ICSI. At the meeting in Cairo on February 18, 2019, the evidence was presented and discussed and a series of consensus points agreed.

RESULTS

The paper presents a background and summary of the evidence relating to these four topics and addresses key points of significance. Following discussion of the evidence, a total of 36 consensus points were agreed.

DISCUSSION

The Discussion section presents areas where there was further debate and key areas that were highlighted during the day.

CONCLUSION

The consensus points provide clear statements of evidence gaps and/or potential future research areas/topics. Appropriate funding streams addressing these can be prioritized and consequently, in the short and medium term, answers provided. By using this strategic approach, andrology can make the rapid progress necessary to address key scientific, clinical, and societal challenges that face our discipline now and in the near future.

Loss-of-function mutations in centrosomal protein 112 is associated with human acephalic spermatozoa phenotype

Acephalic spermatozoa, characterized by the headless sperm in the ejaculate, is a rare type of teratozoospermia. Here, we recruited two infertile patients with an acephalic spermatozoa phenotype to investigate the genetic pathology of acephalic spermatozoa. Whole-exome sequencing analysis was performed and found mutations in CEP112 in the two patients: homozygous mutation c.496C > T:p.(Arg166X) in exon 5 from P1; and the biallelic mutations c.2074C > T:p.(Arg692Trp) in exon 20 and c.2104C > T:p.(Arg702Cys) in exon 20 from P2. Sanger sequencing confirmed the CEP112 mutations in the two patients. In silico analysis revealed that these CEP112 mutations are deleterious and rare, and all the mutations impact the coiled-coil domain of CEP112, which may affect the protein function. The c.496C > T:p.Arg166X resulted in a truncated CEP112, which was verified by the mutation expression plasmid. The CEP112 expression was significantly reduced in the P2, suggesting the biallelic mutations c.2074C > T and c.2104C > T may affect the function and stability of CEP112. Therefore, we speculate that the loss-of-function mutations in CEP112 may be account for the human acephalic spermatozoa phenotype.

Clinical factors affecting semen improvement after microsurgical subinguinal varicocelectomy: which subfertile patients benefit from surgery?

Background

The exact mechanism of varicocele-related infertility is still elusive, therefore, the current challenges for its management lie in determining which patients stand to benefit most from surgical correction. The authors aimed to assess the clinical factors affecting semen improvement after left microsurgical subinguinal varicocelectomy (MSV) in relation to patient age, ultrasound varicocele grading (USVG), and presence of a right subclinical varicocele (RSV).

Methods

From 2010 to 2017 a total of 228 infertile patients underwent left MSV for clinical varicocele. Descriptive statistics were used to describe the cohort and verify the surgical benefit in terms of semen improvement, in addition, subsets of patients were selected according to clinical covariates. Logistic regression modeling was applied to evaluate the presence of RSV, operative time, age, and USVG as explanatory variables.

Results

Sperm concentration (SC), progressive sperm motility (PSM), and normal sperm morphology (NSM) increased significantly after surgery (p = 0.002; p = 0.011; p = 0.024; respectively). Mean SC improved after MSV in ⩾35 year-old patients and the grade 3 USVG group (p = 0.01; p = 0.02; respectively). Logistic regression modeling showed a that the probability of SC improvement was 76% lower in subjects presenting RSV (p = 0.011). In addition, patients with a grade 3 USVG presented a three-times greater probability of SC improvement compared with patients with a lower USVG (p = 0.035). In addition, older patients showed a greater probability of SC improvement after MSV (p = 0.041).

Conclusions

MSV is an effective varicocele-related infertility treatment that should also be offered to older patients. In addition, patients with a higher USVG benefit from surgery. In infertile men with an RSV in association with a left clinical disease, a bilateral varicocele repair should be considered.

Male Oxidative Stress Infertility (MOSI): Proposed Terminology and Clinical Practice Guidelines for Management of Idiopathic Male Infertility

Despite advances in the field of male reproductive health, idiopathic male infertility, in which a man has altered semen characteristics without an identifiable cause and there is no female factor infertility, remains a challenging condition to diagnose and manage. Increasing evidence suggests that oxidative stress (OS) plays an independent role in the etiology of male infertility, with 30% to 80% of infertile men having elevated seminal reactive oxygen species levels. OS can negatively affect fertility via a number of pathways, including interference with capacitation and possible damage to sperm membrane and DNA, which may impair the sperm's potential to fertilize an egg and develop into a healthy embryo. Adequate evaluation of male reproductive potential should therefore include an assessment of sperm OS. We propose the term Male Oxidative Stress Infertility, or MOSI, as a novel descriptor for infertile men with abnormal semen characteristics and OS, including many patients who were previously classified as having idiopathic male infertility. Oxidation-reduction potential (ORP) can be a useful clinical biomarker for the classification of MOSI, as it takes into account the levels of both oxidants and reductants (antioxidants). Current treatment protocols for OS, including the use of antioxidants, are not evidence-based and have the potential for complications and increased healthcare-related expenditures. Utilizing an easy, reproducible, and cost-effective test to measure ORP may provide a more targeted, reliable approach for administering antioxidant therapy while minimizing the risk of antioxidant overdose. With the increasing awareness and understanding of MOSI as a distinct male infertility diagnosis, future research endeavors can facilitate the development of evidence-based treatments that target its underlying cause.

Clinical and molecular characterization of Y microdeletions and X-linked CNV67 implications in male fertility: a 20-year experience

BACKGROUND

Approximately 15% of couples worldwide are affected with infertility, attributed to a male co-factor in about half of the cases. Y chromosome microdeletions are the second most common genetic cause for male infertility, with a global prevalence of 2-10% in infertile men. Recently, CNV67, localized in X chromosome, has emerged as potential contributor to male infertility, with a described frequency of 1.1% in the oligo/azoospermic men.

OBJECTIVES

To investigate the prevalence of Y-linked CNVs in a cohort of Portuguese infertile men and correlate the patients' phenotypes with a genetic alteration; to investigate the CNV67 deletion in a subset of patients and corroborate the role of this CNV in male infertility.

MATERIALS AND METHODS

We retrospectively analysed a database of 4000 Portuguese infertile men for karyotype anomalies and Y microdeletions and selected a cohort of 400 for CNV67 screening analysis by quantitative PCR or single PCR plus/minus.

RESULTS

Karyotype anomalies were present in 263 patients (6.6%), with Klinefelter syndrome representing the most frequent karyotype anomaly (2.8%). Among the 4000 patients, the prevalence of Yq microdeletions was 4.6%. Ninety microdeletions (10.0%) were found in the azoospermic group, 44 deletions (4.5%) in the severe oligozoospermic group, 1 AZFc partial deletion (0.3%) in the mild-moderate oligozoospermic group and 2 partial AZFc deletions (0.4%) in the normozoospermic group. Complete AZFc deletions represented 56.8% of the Yq microdeletions. The CNV67 deletion frequency was 1.2% in the studied sample.

CONCLUSIONS

This study presents one of the largest samples of infertile men worldwide with the main purpose of correlating the Yq microdeletions with sperm count. Our findings are supported by previous reviews with large data and provide a reliable estimation of the prevalence of these anomalies in a Portuguese population. CNV67 was exclusively deleted in patients with spermatogenic impairment, showing a consistent genotype-phenotype correlation and a significant prevalence.

Identification of circulating small non-coding RNAs in relation to male subfertility and reproductive hormones

Male subfertility is often associated with sub-optimal health status and traditional semen and hormone analysis reveal only limited information about the reduced fertility potential. Circulating small non-coding RNAs (sncRNAs) are paracrine and endocrine messengers, with prognostic potential. Here, we utilised small RNA-Seq to identify novel cell-free circulating sncRNAs that could act as potential biomarkers of male subfertility. We analysed sera from twelve subfertile men and four controls. The subfertile men were further sub-divided into the three groups based on reproductive hormone levels: group 1 (n = 4): hormone levels similar to the controls, group 2 (n = 4) showing elevated FSH levels, and group 3 (n = 4) with low total testosterone (TT). Total RNA was extracted from serum and sequenced to identify miRNAs and piRNAs. Selected sncRNAs were qPCR validated in a larger and independent cohort of subfertile men (n = 57) and normozoospermic controls (n = 19). RNA-Seq resulted in the identification of 1123 and 330 circulating miRNAs and piRNAs, respectively. Several miRNAs and piRNAs were differentially (p = 0.05) present between controls and subfertile men. Subfertile men with low TT appeared to have a distinct sncRNA profile, compared to group 1 and 2. Validation of two miRNAs (hsa-miR-542-5p and hsa-let-7i-3p) and one piRNA (hsa-piR-26399) in an independent cohort confirmed a significant difference in circulating levels between subfertile and control men. Enrichment analysis of the putative miRNA targets showed association with steroid biosynthesis pathway highlighting a potential regulatory role of these miRNAs. We propose that circulating sncRNAs may represent new important functional biomarkers in male reproductive endocrinology.

Clinical Use of FSH in Male Infertility

The established clinical indication for FSH use in male infertility is the treatment of patients with hypogonadotropic hypogonadism for stimulation of spermatogenesis that allows the induction of a clinical pregnancy in the female partner and finally the birth of a healthy child. Several clinical studies with urinary, purified, and recombinant FSH preparations in combination with hCG have demonstrated the high treatment efficacy regarding these clinical endpoints. Shortcomings of this hormone therapy are the long duration of treatment, sometimes longer than 2 years, and the inconvenience of injections every second or third day. However, improvements of therapy might be expected with new hormonal treatment options already available for infertility treatment in the female. FSH use for treatment of patients with normogonadotropic idiopathic infertility and oligozoospermia is still considered experimental in most countries. Recent meta-analyses have shown that FSH can significantly increase pregnancy rates in the female partners of these patients, but the effect-size is relatively low. Therefore, predictive factors for treatment success have to be identified, including FSH pharmacogenetics, to select the right normogonadotropic patients with idiopathic infertility for FSH therapy.

Pharmacogenetics of FSH Action in the Male

Male infertility is a major contributor to couple infertility, however in most cases it remains "idiopathic" and putative treatment regimens are lacking. This leads to a scenario in which intra-cytoplasmic spermatozoa injection (ICSI) is widely used in idiopathic male infertility, though the treatment burden is high for the couple and it entails considerable costs and risks. Given the crucial role of the Follicle-stimulating hormone (FSH) for spermatogenesis, FSH has been used empirically to improve semen parameters, but the response to FSH varied strongly among treated infertile men. Single nucleotide polymorphisms (SNPs) within FSH ligand/receptor genes (FSHB/FSHR), significantly influencing reproductive parameters in men, represent promising candidates to serve as pharmacogenetic markers to improve prediction of response to FSH. Consequently, several FSH-based pharmacogenetic studies have been conducted within the last years with unfortunately wide divergence concerning selection criteria, treatment and primary endpoints. In this review we therefore outline the current knowledge on single nucleotide polymorphisms (SNPs) in the FSH and FSH receptor genes and their putative functional effects. We compile and critically assess the previously performed pharmacogenetic studies in the male and propose a putative strategy that might allow identifying patients who could benefit from FSH treatment.