Seminal plasma concentrations of Anti-Müllerian hormone and inhibin B predict motile sperm recovery from cryopreserved semen in asthenozoospermic men: a prospective cohort study

Low-serum antimüllerian hormone is linked with poor semen quality in infertile men screened for participation in a randomized controlled trial

OBJECTIVE

To investigate possible associations between serum antimüllerian hormone (AMH) concentration and semen quality in infertile men. Studies investigating the associations between serum AMH concentration and semen quality in infertile men have shown conflicting results.

DESIGN

Infertile men were included during screening for participation in the First in Treating Male Infertility Study, a double-blinded, placebo-controlled, 1:1, single-center randomized controlled trial.

SETTING

Not applicable.

PATIENTS

At the screening visit, 400 participants produced a semen sample and had their serum analyzed for AMH concentration.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Serum AMH concentration and semen quality.

RESULTS

All men were stratified according to serum AMH concentrations in quartiles (Q1-Q4). Men in the lowest quartile had a lower sperm concentration (1 × 106/mL) (Q1: 8.0 vs. Q2: 10.4 vs. Q3: 11.0 vs. Q4: 13.0), total sperm count (1 × 106) (Q1: 29.1 vs. Q2: 38.2 vs. Q3: 44.4 vs. Q4: 55.7), sperm motility (%) (Q1: 41 vs. Q2: 57 vs. Q3: 50 vs. Q4: 53), and progressive sperm motility (%) (Q1: 31 vs. Q2: 44 vs. Q3: 35 vs. Q4: 40) compared with the other quartiles. Moreover, men with a sperm concentration <2 million/mL had a lower serum AMH concentration compared with men having 2-16 × 106 /mL and >16 × 106/mL (31 pmol/L vs. 38 pmol/L vs. 43 pmol/L, respectively). In accordance, men with sperm motility <20% had a lower serum AMH concentration compared with men with sperm motility 20%-42%, and >42% (31 pmol/L vs. 43 pmol/L. vs. 39 pmol/L, respectively).

CONCLUSION

This study shows that low serum AMH concentration is associated with poor semen quality in infertile men, which implies that serum AMH concentration may have clinical value during the evaluation of male infertility.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05212337.

Poor Sperm Chromatin Condensation Is Associated with Cryopreservation-Induced DNA Fragmentation and Cell Death in Human Spermatozoa

Background/Objectives: Semen cryopreservation is routinely performed in fertility clinics for a variety of reasons, including fertility preservation and storage of donor sperm, yet the freeze-thaw process leads to cellular damage via ice crystal formation, osmotic shock, and supraphysiological levels of oxidative stress. Sperm resistance to damage during the freeze-thaw process varies widely, yet the intrinsic factors associated with sperm cryotolerance are largely unknown. The study aimed to investigate whether poor chromatin condensation renders sperm vulnerable to DNA fragmentation and cell death induced by the freeze-thaw process. Methods: Participants (n = 51) from the general community who met the inclusion criteria collected a semen sample after 3-8 days of abstinence. Neat semen samples underwent traditional semen analysis, aniline blue (AB)-eosin staining for chromatin condensation, the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay for DNA fragmentation, and the Annexin V assay for apoptosis/necrosis, prior to being cryopreserved using the liquid nitrogen vapour method and stored at -196 °C. Stored samples were later thawed at room temperature and processed using density gradient centrifugation. Motile sperm concentration, DNA fragmentation and apoptosis/necrosis were analysed in post-thaw samples. Results: As indicated by a significant interaction effect in linear mixed models, an increased proportion of AB-positive sperm in the pre-freeze sample exacerbated the adverse effect of freezing on sperm DNA fragmentation (p = 0.004), late apoptosis (p = 0.007), and necrosis (p = 0.007). AB-staining was positively correlated with all three parameters in the post-thaw sample (all rs ≥ 0.424, all p < 0.01) and remained significant after adjusting for neat sperm concentration (all partial rs ≥ 0.493, all p < 0.01). Similarly, AB-staining was significantly correlated with the percentage point change in sperm DNA fragmentation (rs = 0.366, p = 0.014) and necrosis (rs = 0.403, p = 0.009), both of which remained significant after adjusting for neat sperm concentration (both partial rs ≥ 0.404, both p < 0.01), and borderline significantly correlated with percentage point change in late apoptosis (rs = 0.307, p = 0.051). Conclusions: Sperm with poorly condensed chromatin may be more susceptible to cellular damage during the freeze-thaw process, independent of pre-freeze sperm concentration. These findings may help to explain the intrinsic variation in sperm resistance to cryodamage within and between individuals that is poorly understood.

Inhibin B and antiMüllerian hormone as surrogate markers of fertility in male and female Crohn's disease patients: a case-control study

Background

Several studies suggest that women with Crohn disease (CD) have reduced fertility due to decreased ovarian reserve, among other causes. On the other hand, male CD patients could have difficulties conceiving. The present study aimed to test the effect of CD on both male and female fertility potential, Sertoli cell function and ovarian reserve, assessed by inhibin-B (IB) plus IB:FSH ratio (IFR) and antiMüllerian hormone (AMH), respectively. Sexual dysfunction (SD) was studied as secondary endpoint.

Methods

We performed a cross-sectional, case-control study. Serum IB levels plus IFR were measured in 58 men with CD and compared to 25 age-matched healthy controls (HC). Serum AMH levels were measured in 50 women with CD and in 30 HC matched by age. SD was assessed by means of the International Index of Erectile Function (IIFE-15) in males and the Index of Female Sexual Function (IFSF) in women.

Results

A total of 108 CD patients and 55 HC were included. IB serum levels were significantly lower in CD men than in HC (177 ± 58 vs. 234 ± 75 pg./mL, p = 0.001). IFR was also decreased in CD patients compared to HC (58.27 ± 59.5 vs. 91.35 ± 60.04, p = 0.014). Women with CD > 30 years had lower serum AMH levels compared to HC (1.15 ± 0.74 vs. 2.14 ± 1.68 ng/mL, p = 0.033). In addition, CD women >30 years presented a serum AMH < 2 ng/mL more frequently than HC (90% vs. 40%, p = 0.004). The prevalence of SD was significantly higher among both male and female CD patients compared to HC, without association to fertility potential. Age was the only predictor of low ovarian reserve.

Conclusion

Testicular Sertoli cell function assessed through serum IB levels and IFR is decreased in CD male patients compared to HC, regardless of age. Age > 30 years is the single independent predictor of reduced ovarian reserve in women with CD. These results should be confirmed in further studies in order to properly counsel patients with CD and desire for offspring.

Role of Anti-Müllerian Hormone in Male Reproduction and Sperm Motility

Anti-Müllerian hormone (AMH) is secreted by Sertoli cells and is responsible for the regression of Müllerian ducts in the male fetus as part of the sexual differentiation process. Serum AMH concentrations are at their lowest levels in the first days after birth but increase after the first week, likely reflecting active Sertoli cell proliferation. AMH rises rapidly in concentration in boys during the first month, reaching a peak level at ∼6 months of age, and it remains high during childhood, then they will slowly decline during puberty, falling to low levels in adulthood. Serum AMH measurement is used by pediatric endocrinologist as a specific marker of immature Sertoli cell number and function during childhood. After puberty, AMH is released especially by the apical pole of the Sertoli cells toward the lumen of the seminiferous tubules, resulting in higher levels in the seminal plasma than in the serum. Recently, AMH has received increasing attention in research on male fertility-related disorders. This article reviews and summarizes the potential contribution of serum AMH measurement in different male fertility-related disorders.

Effect of Honey, Coenzyme Q10, and β-Carotene/α-Tocopherol as Novel Additives in Rabbit-Sperm Cryopreservation Extender

The effectiveness of rabbit-sperm cryopreservation is still below average compared to other domestic species. After the sperm cryopreservation process, post-thawing parameters like motility and membrane integrity are significantly compromised. The use of new extender constituents is an approach that can be used to improve the effectiveness of cryopreservation. Accordingly, we used honey (1.25, 2.5, 5, and 10%), coenzyme Q10 (100 and 200 μM), and β-carotene/α-tocopherol (500 μM/620 μM and 250 μM/310 μM) as candidate components for rabbit-sperm extenders during cryopreservation. Ejaculates from commercial adult rabbit bucks (n = 5) were cryopreserved using conventional freezing. Several post-thawing sperm parameters were assessed, including total motility, membrane integrity, viability, nuclear membrane integrity, acrosome reaction, and mitochondrial membrane potential and activation. Additionally, we performed hormonal analyses of the seminal plasma. Moreover, we analyzed the post-thawing levels of a molecular marker of sperm quality, proAKAP4, which was used in rabbits for the first time. Our findings showed that the 2.5% honey supplementation increased the post-thawing sperm motility (13.75 ± 3.75%) compared to the greater concentrations employed. However, the post-thawing motility was negatively affected by the coenzyme Q10 (0%, in both groups) but was not affected by the β-carotene/α-tocopherol supplementation (22 ± 18.15%, and 11.67 ± 10.17%). In conclusion, the cryopreservation protocols of this study did not help to maintain the sperm parameters after thawing. Further studies are required to identify novel protocols to mitigate the damage caused to rabbit sperm during cryopreservation.

Defining Reference Ranges for Serum Anti-Müllerian Hormone on a Large Cohort of Normozoospermic Adult Men Highlights New Potential Physiological Functions of AMH on FSH Secretion and Sperm Motility

BACKGROUND

Few studies to date have attempted to measure serum anti-Müllerian hormone (AMH) levels in adult men, and solid references ranges have not yet been defined in a large cohort.

OBJECTIVE

In this study, we aimed, first, to establish the reference ranges for serum AMH and AMH-to-total testosterone ratio (AMH/tT) in adult males. Second, we investigated the relationship between serum AMH and both reproductive hormones and semen parameters.

METHODS

This single-center retrospective study included 578 normozoospermic adult men. Serum AMH concentrations were determined with an automated sandwich chemiluminescent immunoassay.

RESULTS

The median serum AMH was 43.5 pmol/L. The 2.5th and 97.5th percentile values for serum AMH and AMH/tT were 16.4 and 90.3 pmol/L and 0.45 and 3.43, respectively. AMH was positively correlated with inhibin B and sperm concentration and negatively correlated with age, follicle-stimulating hormone (FSH), and progressive sperm motility. Interestingly, using immunofluorescence, we documented for the first time that AMH type II receptor (AMH-R2) is expressed in ejaculated human spermatozoa and gonadotrophic cells in the postmortem pituitary gland.

CONCLUSIONS

We establish a new age-specific reference range for serum AMH and AMH/tT. Moreover, AMH-R2 expression in human spermatozoa and gonadotrophic cells, together with the relationship between serum AMH levels and sperm motility or mean FSH levels, highlight new potential functions of AMH in regulating sperm motility or FSH secretion in adult men.

An Integrated Analysis of Network Pharmacology, Molecular Docking, and Experiment Validation to Explore the New Candidate Active Component and Mechanism of Cuscutae Semen-Mori Fructus Coupled-Herbs in Treating Oligoasthenozoospermia

PURPOSE

One of the most common types of male infertility is recognized as oligoasthenozoospermia (OA), characterized by low sperm count and quality in males. As a traditional Chinese medicine (TCM), Cuscutae Semen-Mori Fructus coupled-herbs (CSMFCH) has been known to act a curative effect on OA for thousands of years. Nevertheless, the substantial basis and molecular mechanism of CSMFCH in treating OA remain elusive.

METHODS

Herein, an integrated approach, including network pharmacology, molecular docking, and experiment validation, was utilized to reveal the new candidate active component and mechanism of CSMFCH in treating OA.

RESULTS

The results show that kaempferol is the most significant bioactive component of CSMFCH on OA. The mechanism and targets of CSMFCH against OA are relevant to hormone regulation, oxidant stress, and reproductive promotion. In order to validate network pharmacology results, molecular docking and experiment validation were conducted. In detail, molecular docking was employed to verify the strong binding interactions between kaempferol and the core targets. UHPLC-Q-Orbitrap-MS was used to identify kaempferol in the CSMFCH extract. In vitro and in vivo experiments further proved CSMFCH and kaempferol could enhance the mouse Leydig (TM3) and mouse Sertoli (TM4) cell viability, improve the male reproductive organ weights, sperm quality, and decrease testis tissue damage in the OA mouse model induced by CP.

CONCLUSION

Our results not only identify the new candidate active component of CSMFCH in treating OA but also provide new insights into the mechanisms of CSMFCH against OA.

Global Methylation and Protamine Deficiency in Ram Spermatozoa Correlate with Sperm Production and Quality but Are Not Influenced by Melatonin or Season

Simple Summary

Though environmental factors can alter the epigenome of mammalian spermatozoa, it is currently unclear whether these epigenetic changes are linked to sperm production, quality and fertility. This study aimed to identify whether the hormone melatonin, responsible for upregulating ram reproductive function, is able to alter broad epigenetic markers in spermatozoa, namely sperm global methylation and protamine deficiency. It was also investigated whether these parameters corresponded to ram endocrinology, semen production and quality. Though no effects of season or melatonin were found, both sperm global methylation and protamine deficiency correlated with several semen production and quality parameters. These moderate associations with sperm production and quality support that sperm protamine deficiency and global methylation are broadly indicative of testicular function.

Abstract

This study assessed whether the seasonal effects of melatonin that upregulate ram reproductive function alter sperm global methylation or protamine deficiency and whether these parameters corresponded to ram endocrinology, semen production and quality. Ejaculates were assessed from rams that received melatonin implants (n = 9) or no implants (n = 9) during the non-breeding season. Ejaculates (n = 2/ram/week) were collected prior to implantation (week 0), 1, 6 and 12 weeks post implantation and during the following breeding season (week 30). Flow cytometry was used to assess the sperm global methylation and protamine deficiency in each ejaculate, which had known values for sperm concentration, motility, morphology, DNA fragmentation, seminal plasma levels of melatonin, anti-Mullerian hormone and inhibin A. Serum levels of testosterone and melatonin were also evaluated. Though there was no effect of melatonin or season, sperm protamine deficiency was negatively correlated with sperm production and seminal plasma levels of anti-Mullerian hormone and positively correlated with sperm DNA fragmentation and morphology. Global methylation of spermatozoa was positively correlated with sperm DNA fragmentation, morphology and serum testosterone and negatively correlated with sperm motility. These moderate associations with sperm production and quality suggest that sperm protamine deficiency and global methylation are indicative of ram testicular function.

Exosome Composition and Seminal Plasma Proteome: A Promising Source of Biomarkers of Male Infertility

Infertility has become a global health issue, with approximately 50% of infertility cases generated by disorders in male reproduction. Spermatozoa are conveyed towards female genital tracts in a safe surrounding provided by the seminal plasma. Interestingly, this dynamically changing medium is a rich source of proteins, essential not only for sperm transport, but also for its protection and maturation. Most of the seminal proteins are acquired by spermatozoa in transit through exosomes (epididymosomes and prostasomes). The high number of seminal proteins, the increasing knowledge of their origins and biological functions and their differential expression in the case of azoospermia, asthenozoospermia, oligozoospermia and teratozoospermia or other conditions of male infertility have allowed the identification of a wide variety of biomarker candidates and their involvement in biological pathways, thus to strongly suggest that the proteomic landscape of seminal plasma may be a potential indicator of sperm dysfunction. This review summarizes the current knowledge in seminal plasma proteomics and its potentiality as a diagnostic tool in different degrees of male infertility.

Seminal protein levels assessed with dipstick test correlate with sperm recovery after cryopreservation

The process of freezing/thawing causes structural and functional damage to sperm samples, which can be mitigated by seminal plasma proteins. This study investigated the proposition that seminal protein measurements using a urinary dipstick prior to freezing could help predict the post-thaw recovery of live spermatozoa. This was a prospective study including 149 men undergoing semen analysis due to male and/or female infertility. The seminal samples were analysed according to World Health Organisation standards and protein concentrations were measured using a commercially available urinary dipstick following quantitative validation. The median live sperm recovery rates were 79%, 81% and 94%, respectively, in samples with protein concentrations of ≤1.0 g/L (+/++), 3.0 g/L (+++) and ≥20.0 g/L (++++) measured in fresh specimen dipstick analysis (p < 0.05) indicating that the probability of recovering at least 50% of frozen spermatozoa increased progressively with higher protein concentrations in the fresh sample (chi-square for linear association = 7.17. p = 0.007). In conclusion, fresh seminal protein concentration levels assessed with a dipstick test correlate with the proportion of live spermatozoa recovered from cryopreserved samples. This simple, low-cost test may add prognostic information to baseline semen analysis prior to sperm banking.

Exogenous melatonin advances the ram breeding season and increases testicular function

Governed by melatonin, ovine reproductive seasonality limits production outcomes due to periods of decreased reproductive efficiency. Though it is established that slow-release melatonin implants improve out of season reproductive performance in the ewe, the comprehensive effects of exogenous melatonin in the ram remain inconclusive. This study aimed to ultimately clarify the ability of exogenous melatonin to alter ram reproductive function during the non-breeding season and the subsequent breeding season. Hence, we investigated the effect of exogenous melatonin on reproductive endocrinology, semen quality and production, testicular size and libido in Merino and Poll Dorset rams (n = 31, using a subset of 18 rams for analysis of semen production and quality). Melatonin treatment resulted in elevation of melatonin in seminal plasma from 1-8 weeks post-implantation and in blood plasma at 6 weeks post-implantation. The blood plasma testosterone of implanted rams was greater than controls at both 6 weeks post-implantation and during the following breeding season. Implanted rams exhibited increased testicular size and number of sperm per ejaculate from 3-12 weeks post-implantation but did not demonstrate any change in sperm motility or morphology in response to treatment. Compared to their control counterparts, melatonin-treated Poll Dorset rams exhibited a lower percentage of sperm DNA fragmentation during several weeks of the non-breeding season. Though melatonin increased the likelihood of ejaculate collection in Poll Dorset rams (P < 0.05), libido was otherwise unaffected by treatment. Melatonin did not alter seminal plasma concentrations of inhibin A or Anti-Mullerian hormone, however, for the first time in the ram we have shown Anti-Mullerian hormone to be positively correlated with the number of sperm per ejaculate and sperm motility (r = 0.464 and 0.3242 respectively, P < 0.001), and inhibin A to be correlated to the number of sperm per ejaculate (r = 0.1786, P = 0.0135). These results indicate that melatonin is able to both systemically upregulate reproduction and act directly upon testicular function in the ram.

Seminal Plasma Anti-Müllerian Hormone: A Potential AI-Boar Fertility Biomarker?

The anti-Müllerian hormone (AMH), a Sertoli cell-secreted glycoprotein that is present in seminal plasma (SP), is considered as a marker of spermatogenesis in humans. This study aimed to evaluate the presence of this hormone in boar SP, together with its putative relationship with sperm quality, function, and in vivo fertility parameters in liquid-stored semen samples. The concentration of SP-AMH was assessed in 126 ejaculates from artificial insemination (AI)-boars (n = 92) while using a commercial Enzyme-Linked ImmunoSorbent Assay (ELISA) kit with monoclonal antibodies specific for Sus scrofa AMH (CEA228Po, Cloud-clone). Sperm quality (concentration, motility, viability, and acrosome damage) and functionality (membrane lipid disorder and intracellular H₂O₂ generation) were assessed in semen samples at 0 and 72 h of liquid-storage. In addition, fertility parameters from 3113 sows inseminated with the AI-boars were recorded in terms of farrowing rate, litter size, number of stillbirths per litter, and the duration of pregnancy over a 12-month period. The results revealed that the SP-AMH concentration varied widely among boar ejaculates, with no differences among breeds. Moreover, the SP-AMH concentration proved to be a good predictive biomarker for sperm concentration (p ˂ 0.05), but poor for other sperm quality, functionality, and in vivo fertility parameters of liquid-stored semen samples from AI-boars.

Rosiglitazone ameliorates palmitic acid-induced cytotoxicity in TM4 Sertoli cells

The Sertoli cell is the only somatic cell within the seminiferous tubules, and is vital for testis development and spermatogenesis. Rosiglitazone (RSG) is a member of the thiazolidinedione family and is a peroxisome proliferator-activated receptor-γ (PPARγ) agonist. It has been reported that RSG protects various types of cells from fatty acid-induced damage. However, whether RSG serves a protective role in Sertoli cells against palmitic acid (PA)-induced toxicity remains to be elucidated. Therefore, the aim of the present study was to investigate the effect of RSG on PA-induced cytotoxicity in Sertoli cells. MTT assay and Oil Red O staining revealed that RSG ameliorated the PA-induced decrease in TM4 cell viability, which was accompanied by an alleviation of PA-induced lipid accumulation in cells. In primary mouse Sertoli cells, RSG also showed similar protective effects against PA-induced lipotoxicity. Knockdown of PPARγ verified that RSG exerted its protective role in TM4 cells through a PPARγ-dependent pathway. To evaluate the mechanism underlying the protective role of RSG on PA-induced lipotoxicity, the present study analyzed the effects of RSG on PA uptake, and the expression of genes associated with both fatty acid oxidation and triglyceride synthesis. The results demonstrated that although RSG did not affect the endocytosis of PA, it significantly elevated the expression of carnitine palmitoyltransferase (CPT)-1A, a key enzyme involved in fatty acid oxidation, which indicated that the protective effect of RSG may have an important role in fatty acid oxidation. On the other hand, the expression of CPT1B was not affected by RSG. Moreover, the expression levels of diacylglycerol O-acyltransferase (DGAT)-1 and DGAT2, both of which encode enzymes catalyzing the synthesis of triglycerides, were not suppressed by RSG. The results indicated that RSG reduced PA-induced lipid accumulation by promoting fatty acid oxidation mediated by CPT1A. The effect of RSG in protecting cells from lipotoxicity was also found to be specific to Sertoli cells and hepatocytes, and not to other cell types that do not store excess lipid in large quantities, such as human umbilical vein endothelial cells. These findings provide insights into the cytoprotective effects of RSG on Sertoli cells and suggest that PPARγ activation may be a useful therapeutic method for the treatment of Sertoli cell dysfunction caused by dyslipidemia.

Occurrence and reproductive roles of hormones in seminal plasma

Only 2-5% of seminal fluid is composed of spermatozoa, while the rest is seminal plasma. The seminal plasma is a rich cocktail of organic and inorganic compounds including hormones, serving as a source of nutrients for sperm development and maturation, protecting them from infection and enabling them to overcome the immunological and chemical environment of the female reproductive tract. In this review, a survey of the hormones found in human seminal plasma, with particular emphasis on reproductive hormones is provided. Their participation in fertilization is discussed including their indispensable role in ovum fertilization. The origin of individual hormones found in seminal plasma is discussed, along with differences in the concentrations in seminal plasma and blood plasma. A part of review is devoted to methods of measurement, emphasising particular instances in which they differ from measurement in blood plasma. These methods include separation techniques, overcoming the matrix effect and current ways for end-point measurement, focusing on so called hyphenated techniques as a combination of chromatographic separation and mass spectrometry. Finally, the informative value of their determination as markers of male fertility disorders (impaired spermatogenesis, abnormal sperm parameters, varicocele) is discussed, along with instances where measuring their levels in seminal plasma is preferable to measurement of levels in blood plasma.