Altered serum profile of inhibin B, Pro-alphaC and anti-Müllerian hormone in prepubertal and pubertal boys with varicocele

Assessment of testicular function in boys and adolescents

OBJECTIVE

The hypothalamic-pituitary-testicular axis is characterised by the existence of major functional changes from its establishment in fetal life until the end of puberty. The assessment of serum testosterone and gonadotrophins and semen analysis, typically used in the adult male, is not applicable during most of infancy and childhood. On the other hand, the disorders of gonadal axis have different clinical consequences depending on the developmental stage at which the dysfunction is established. This review addresses the approaches to evaluate the hypothalamic-pituitary-testicular axis in the newborn, during childhood and at pubertal age.

DESIGN

We focused on the hormonal laboratory and genetic studies as well as on the clinical signs and imaging studies that guide the aetiological diagnosis and the functional status of the gonads.

RESULTS

Serum gonadotrophin and testosterone determination is useful in the first 3-6 months after birth and at pubertal age, whereas AMH and inhibin B are useful biomarkers of testis function from birth until the end of puberty. Clinical and imaging signs are helpful to appraise testicular hormone actions during fetal and postnatal life.

CONCLUSIONS

The interpretation of results derived from the assessment of hypothalamic-pituitary-testicular in paediatric patients requires a comprehensive knowledge of the developmental physiology of the axis to understand its pathophysiology and reach an accurate diagnosis of its disorders.

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.

Varicocele: An Endocrinological Perspective

Varicocele affects 15% of male population but it is more frequently identified in patients searching medical care for infertility. The impact of varicocele on semen production and fertility is known, but the relationship between clinical varicocele and impaired hormonal production is not clear. In published literature there are some studies regarding hormonal alterations in patients with varicocele but no review in which all the hormonal findings are explained. The aim of this review is to evaluate, by most common search engine, what is known about hormonal alterations in varicocele-bearing patients, to verify if a cause-effect relationship is documented and to give a useful contribution to in clinical management of this kind of patients. We found contradictory results about hormonal status from literature. Some studies confirmed a decrease of testosterone levels and higher FSH and LH levels that normalize after varicocelectomy, others found lower than normal levels of dihydrotestosterone due to decreased activity of epididymal 5-α-reductase. Lower circulating Anti-Müllerian Hormone levels, accompanied by a decreased Inhibin-B level, were reported as indicators of the decreased Sertoli cells function in varicocele-bearing adult patients. The finding of higher basal 17-OH-progesterone concentrations in patients with varicocele was explained by some authors with a testicular C-17,20-lyase deficiency. There is no doubt that varicocele could led to hormonal alterations. This review proposes that the impaired free sexual steroid levels are the result of a slight, deep-rooted defect in the testes of a certain amount of men with varicocele but further multicentre, randomized controlled studies remain mandatory to better clarify the hormonal features of patients with varicocele and to assess the utility of hormonal evaluation for establishing the duration of varicocele and for better identifying patients who need surgical correction.

Clinical Applications of Serum Anti-Müllerian Hormone Measurements in Both Males and Females: An Update

Infertility is one of the most common non-communicable diseases, affecting both men and women equally. Ovarian reserve, the number of primordial follicles in the ovaries is believed to be the most important determinants for female fertility. Anti-Müllerian hormone (AMH) secreted from granulosa cells of growing follicles is recognized as the most important biomarker for ovarian reserve. Ovarian reserve models have been developed using AMH and other hormonal indicators, thus childbearing plans and reproductive choices could be arranged by women. In assisted reproductive technology cycles, measurement of AMH helps to predict ovarian response and guide recombinant follicle-stimulating hormone dosing in women. Serum AMH level is increasingly being recognized as a potential surrogate marker for polycystic ovarian morphology, one of the criteria for diagnosis of polycystic ovarian syndrome. AMH is also secreted by Sertoli cells of testes in men, and AMH measurements in the prediction of surgical sperm recovery rate in men have also been investigated. AMH levels are significantly higher in boys than in girls before puberty. Therefore, serum levels of AMH in combination with testosterone is used for the differential diagnosis of disorders of sex development, anorchia, non-obstructive azoospermia, and persistent Müllerian duct syndrome. Recently, serum AMH measurements have also been used in fertility preservation programs in oncofertility, screening for granulosa cell tumors, and prediction of menopause applications. In this review, we will focus on clinical application of AMH in fertility assessments for healthy men and women, as well as for cancer patients.

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Anti-Müllerian hormone (AMH) plays a key role in models assessing ovarian reserve

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AMH is used for the differential diagnosis of disorders of sex development

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AMH provides a molecular marker for related fertility and infertility disorders

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An international standard will aid in the development of various AMH assays

Seminal exosomal miR-210-3p as a potential marker of Sertoli cell damage in Varicocele

BACKGROUND

Varicocoele-associated stressors, such as hypoxia and heat, can damage cell function and viability, and some exosomal biomarkers released from impaired cells may reflect the cell status in testis.

OBJECTIVES

To find if seminal exosomal microRNAs can reflect the Sertoli cell function in varicocoele.

MATERIALS AND METHODS

Experimental left varicocoele rat model was established (n = 24), and patients with different grades of varicocoele (n = 104) were enrolled. Primary rat Sertoli cells were isolated with enzymatic hydrolysis. Exosomes were isolated from primary rat Sertoli cells, rat epididymis tissue, and human seminal plasma with polymer-based precipitation method. Exosomal microRNAs were quantified with qPCR. Inhibin-B was detected with enzyme immunoassay. The correlation analysis between microRNA and inhibin-B was evaluated with Spearman's correlation.

RESULTS

We screened 12 previously reported hypoxia-responsive microRNAs in the primary rat Sertoli cells and found that 4 exosomal microRNAs increased significantly in response to in vitro hypoxia treatment (P < .05). Of the 4 microRNAs, only miR-210-3p was upregulated in the rats with experimental varicocoele (P < .01). In the patients with varicocoele, we found that seminal exosomal miR-210-3p significantly increased in patients with grade II and III varicocoele (P < .01), and miR-210-3p negatively correlated with sperm count (P < .01) and seminal inhibin-B expression (r = -0.39, P < .01). For the 30 patients with microsurgical varicocelectomy, the operation notably decreased miR-210-3p (P < .01).

DISCUSSION AND CONCLUSION

Seminal exosomal miR-210-3p may be a novel, sensitive, and non-invasive biomarker of Sertoli cell damage in varicocoele.

Biomarcadores de hipogonadismo masculino en la infancia y la adolescencia

El eje hipotálamo-hipófiso-testicular es activo en la vida fetal y durante los primeros meses de la vida posnatal: la hipófisis secreta hormona luteinizante (LH) y folículo-estimulante (FSH), mientras que el testículo produce testosterona y factor insulino-símil 3 (INSL3) en las células de Leydig y hormona anti-Mülleriana (AMH) e inhibina B en las células de Sertoli. En la infancia, los niveles séricos de gonadotrofinas, testosterona y factor INSL3 disminuyen a valores prácticamente indetectables, pero los de AMH e inhibina B permanecen altos. En la pubertad, se reactivan las gonadotrofinas y la producción de testosterona e INSL3, aumenta la inhibina y disminuye la AMH, como signo de maduración de la célula de Sertoli. Sobre la base del conocimiento de la fisiología del desarrollo del eje, es posible utilizar clínicamente estos biomarcadores para interpretar la fisiopatología y diagnosticar las diferentes formas de hipogonadismo que pueden presentarse en la infancia y la adolescencia.

Biomarkers of male hypogonadism in childhood and adolescence

Objectives

The objective of this review was to characterize the use of biomarkers of male hypogonadism in childhood and adolescence.

Contents

The hypothalamic-pituitary-gonadal (HPG) axis is active during fetal life and over the first months of postnatal life. The pituitary gland secretes follicle stimulating hormone (FSH) and luteinizing hormone (LH), whereas the testes induce Leydig cells to produce testosterone and insulin-like factor 3 (INSL), and drive Sertoli cells to secrete anti-Müllerian hormone (AMH) and inhibin B. During childhood, serum levels of gonadotropins, testosterone and insulin-like 3 (INSL3) decline to undetectable levels, whereas levels of AMH and inhibin B remain high. During puberty, the production of gonadotropins, testosterone, and INSL3 is reactivated, inhibin B increases, and AMH decreases as a sign of Sertoli cell maturation.

Summary and outlook

Based on our knowledge of the developmental physiology of the HPG axis, these biomarkers can be used in clinical practice to interpret the physiopathology of hypogonadism. Additionally, these markers can have diagnostic value in different forms of hypogonadism that may appear during childhood and adolescence.

Regulation of anti-Müllerian hormone (AMH) in males and the associations of serum AMH with the disorders of male fertility

Anti-Müllerian hormone (AMH) is a functional marker of fetal Sertoli cells. The germ cell number in adults depends on the number of Sertoli cells produced during perinatal development. Recently, AMH has received increasing attention in research of disorders related to male fertility. This paper reviews and summarizes the articles on the regulation of AMH in males and the serum levels of AMH in male fertility-related disorders. We have determined that follicle-stimulating hormone (FSH) promotes AMH transcription in the absence of androgen signaling. Testosterone inhibits the transcriptional activation of AMH. The undetectable levels of serum AMH and testosterone levels indicate a lack of functional testicular tissue, for example, that in patients with anorchia or severe Klinefelter syndrome suffering from impaired spermatogenesis. The normal serum testosterone level and undetectable AMH are highly suggestive of persistent Müllerian duct syndrome (PMDS), combined with clinical manifestations. The levels of both AMH and testosterone are always subnormal in patients with mixed disorders of sex development (DSD). Mixed DSD is an early-onset complete type of disorder with fetal hypogonadism resulting from the dysfunction of both Leydig and Sertoli cells. Serum AMH levels are varying in patients with male fertility-related disorders, including pubertal delay, severe congenital hypogonadotropic hypogonadism, nonobstructive azoospermia, Klinefelter syndrome, varicocele, McCune-Albright syndrome, and male senescence.

Immunohistochemical characterization of the anti-Müllerian hormone receptor type 2 (AMHR-2) in human testes

PURPOSE

In males, AMH is secreted by immature Sertoli cells; following exposure to endogenous androgens, Sertoli cells undergo a process of maturation which ultimately inhibits AMH expression to undetectable levels in the serum. However, expression of AMH receptor (AMHR-2) has never been studied in human testes, and high intratubular concentrations of AMH have been reported in recent literature. We therefore assessed expression of AMHR-2 in several testicular tissue samples by immunohistochemistry (IHC).

METHODS

The IHC method was first validated on tissue samples from healthy human testis (n = 2) and from marmoset ovary (n = 1). The same method was then used for assessment on testicular histopathology specimens from patients with mixed atrophy (MA, n = 2), spermatogenetic arrest (SA, n = 2), Sertoli cell-only syndrome (SCO, n = 1), Klinefelter syndrome (KS, n = 1), and nonseminomatous germ cell tumors (NSGCT, n = 1). Tissue samples from two subjects at different pubertal stages (AndroProtect (AP), aged 5 and 14 years) with hematological malignancies were also retrieved.

RESULTS

In adult men, AMHR-2 was expressed on peritubular mesenchymal cells, with patterns closely mirroring α-smooth muscle actin expression. Similar patterns were preserved in almost all conditions; however, in nonseminomatous germ cell tumors the tissue architecture was lost, including AMHR-2 expression. More positive and diffuse staining was observed in tissue samples from prepubertal testes.

CONCLUSIONS

In specimens from both healthy and affected testes, AMHR-2 expression appears weaker in adult than in prepubertal tissue sections. The persistence of AMHR-2 expression seemingly hints at a possible effect of intratesticular AMH on the tubular walls.

Redox status assessment in infertile patients with non-obstructive azoospermia undergoing testicular sperm extraction: A prospective study

BACKGROUND

Oxidative stress (OS) is one of the most prevalent causes of sperm damage, through the toxic effects of endogenously generated hydrogen peroxide, superoxide anion, and hydroxyl radicals. Peripheral leukocytes represent a feasible model for studying the pathophysiology of OS-mediated homeostasis, which can be responsible for cell dysfunction and cell injury.

OBJECTIVE

To evaluate the redox status in patients with non-obstructive azoospermia (NOA), establishing the potential role exerted by reactive oxygen species (ROS) in the genesis of testicular secretory injury.

MATERIAL AND METHODS

From May 2018 to March 2019, 39 patients were enrolled in this prospective single-center cohort study and divided into two groups. Group 1 included 19 patients with NOA, and Group 2 included 20 normozoospermic men, partners of women with infertility tubal factor. All patients underwent serum blood tests. NOA underwent testicular sperm extraction (TeSE). ROS production (in lymphocytes, monocytes, and granulocytes) was assessed by fluorescence-activated cell sorting (FACS) analysis. Plasma oxidative stress was evaluated by lipid peroxidation markers (MDA) and total antioxidant capacity (TAC) both assessed by fluorometric techniques.

RESULTS

Mean lymphocyte ROS production resulted 967.0 ± 224.5 vs 728.0 ± 98.0 (NOA vs Controls, P < .001), monocyte ROS resulted 2102.5 ± 517.5 vs 1253 ± 171 (P < .001), and granulocyte ROS were 2366.5 ± 595.4 vs 1751.0 ± 213.0 (P < .001). Significant increases plasma lipid peroxidation markers were found in NOA patients compared with controls (2.7 ± 0.8 vs 0.37 ± 0.2 nmol/mL, P < .001). Significant decreased TAC was evident in NOA compared with controls (13.4 ± 3.9 vs 3.0 ± 0.2 µmol/mL Trolox equivalents, P < .001). No significant differences were found in blood leukocyte subpopulations ROS production, plasma lipid peroxidation, and TAC comparing groups (positive vs negative sperm retrieval, P > .05).

CONCLUSION

ROS production can be directly related to disorders of spermatogenesis, leading to severe conditions of male infertility, including azoospermia.

Management and Treatment of Varicocele in Children and Adolescents: An Endocrinologic Perspective

Pediatric varicocele has an overall prevalence of 15%, being more frequent as puberty begins. It can damage testicular function, interfering with Sertoli cell proliferation and hormone secretion, testicular growth and spermatogenesis. Proper management has a pivotal role for future fertility preservation. The aim of this review was to discuss the diagnosis, management and treatment of childhood and adolescent varicocele from an endocrinologic perspective, illustrating the current evidence of the European Society of Pediatric Urology (ESPU), the European Association of Urology (EAU), the American Urological Association (AUA) and the American Society for Reproductive Medicine (ASRM) scientific societies. According to the ASRM/ESPU/AUA practice committee, the treatment of adolescent varicocele is indicated in the case of decreased testicular volume or sperm abnormalities, while it is contraindicated in subclinical varicocele. The recent EAS/ESPU meta-analysis reports that moderate evidence exists on the benefits of varicocele treatment in children and adolescents in terms of testicular volume and sperm concentration increase. No specific phenotype in terms of testicular volume cut-off or peak retrograde flow (PRF) is indicated. Based on current evidence, we suggest that conservative management may be suggested in patients with PRF < 30 cm/s, testicular asymmetry < 10% and no evidence of sperm and hormonal abnormalities. In patients with 10-20% testicular volume asymmetry or 30 < PRF ≤ 38 cm/s or sperm abnormalities, careful follow-up may ensue. In the case of absent catch-up growth or sperm recovery, varicocele repair should be suggested. Finally, treatment can be proposed at the initial consultation in painful varicocele, testicular volume asymmetry ≥ 20%, PRF > 38 cm/s, infertility and failure of testicular development.

Reactive oxygen species and male reproductive hormones

Reports of the increasing incidence of male infertility paired with decreasing semen quality have triggered studies on the effects of lifestyle and environmental factors on the male reproductive potential. There are numerous exogenous and endogenous factors that are able to induce excessive production of reactive oxygen species (ROS) beyond that of cellular antioxidant capacity, thus causing oxidative stress. In turn, oxidative stress negatively affects male reproductive functions and may induce infertility either directly or indirectly by affecting the hypothalamus-pituitary-gonadal (HPG) axis and/or disrupting its crosstalk with other hormonal axes. This review discusses the important exogenous and endogenous factors leading to the generation of ROS in different parts of the male reproductive tract. It also highlights the negative impact of oxidative stress on the regulation and cross-talk between the reproductive hormones. It further describes the mechanism of ROS-induced derangement of male reproductive hormonal profiles that could ultimately lead to male infertility. An understanding of the disruptive effects of ROS on male reproductive hormones would encourage further investigations directed towards the prevention of ROS-mediated hormonal imbalances, which in turn could help in the management of male infertility.

Role of FSH glycan structure in the regulation of Sertoli cell inhibin production

Variations in follicle-stimulating hormone (FSH) carbohydrate composition and structure are associated with important structural and functional changes in Sertoli cells (SCs) during sexual maturation. The aim of the present study was to investigate the impact of FSH oligosaccharide structure and its interaction with gonadal factors on the regulation of monomeric and dimeric inhibin production at different maturation stages of the SC. Recombinant human FSH (rhFSH) glycosylation variants were isolated according to their sialylation degree (AC and BA) and complexity of oligosaccharides (CO and HY). Native rhFSH stimulated inhibin α-subunit (Pro-αC) but did not show any effect on inhibin B (INHB) production in immature SCs isolated from 8-day-old rats. Activin A stimulated INHB and had a synergistic effect on FSH to stimulate Pro-αC. The less acidic/sialylated rhFSH charge analogues, BA, were the only charge analogue mix that stimulated INHB as well as the most potent stimulus for Pro-αC production. Native rhFSH stimulated both Pro-αC and INHB in SCs at a more advanced maturation stage, isolated from 20-day-old rats. In these cells, all rhFSH glycosylation variants increased INHB and Pro-αC production, even in the presence of growth factors. The BA preparation exerted a more marked stimulatory effect on INHB and Pro-αC than the AC. Glycoforms bearing high mannose and hybrid-type oligosaccharides, HY, stimulated INHB and Pro-αC more effectively than those bearing complex oligosaccharides, CO, even in the presence of gonadal growth factors. These findings demonstrate the modulatory effect of FSH oligosaccharide structure on the regulation of inhibin production in the male gonad.

Perspectives in Pediatric Pathology, Chapter 20. Adolescent Varicocele

Varicocele is characterized by elongation, dilatation, and tortuosity of the veins draining the testis and its covers, causing circulatory reflux along the inner spermatic vein [ 1 ]. Varicocele results in progressive testicular lesions and, if untreated, can lead to testicular atrophy [ 2 ]. Varicocele is considered the most frequently identified cause of male infertility [ 3 ]. The mechanisms involved in varicocele formation are not well known and probably are multiple, differing from one patient to another.

The dilemma of adolescent varicocele

Adolescent varicocele is associated with ipsilateral testicular hypotrophy and the concern for future infertility. A testicular size discrepancy greater than 15-20 % between left and right testicle is an indication for treatment to allow catch-up growth in the hope of preventing a future decline in fertility. Some authors advocate for a period of watchful waiting, as normal testicular growth may occur asymmetrically. We review the current literature to highlight some controversies and challenges in management.

Evaluation and Management of the Adolescent Varicocele

PURPOSE

Varicocele is one of the most common genital conditions referred to pediatric urologists. Most adolescents with varicocele are asymptomatic and their fertility future (and surgery benefit) is largely unknown. This review assesses varicocele evaluation, management and indications for repair, as well as types and success of varicocelectomy.

MATERIALS AND METHODS

A systematic literature review was performed on Embase™, PubMed® and Google Scholar™ for adolescent varicocele. Original research articles and relevant reviews were examined, and a synopsis of these data was generated for a comprehensive review of clinical adolescent varicocele management.

RESULTS

The prevalence of adolescent varicocele is similar to the adult population. While ultrasound is the most sensitive method for determining testicular volumes, orchidometer measurement may be adequate to gauge significant discordance. Significant hypotrophy of the affected testis with poor total testicular volume may indicate a testis at risk and warrant surgical repair. Similar findings have been noted with an associated high peak retrograde venous flow. Testicular hypotrophy often resolves following surgery but may also improve spontaneously if followed through adolescence. Continued scrotal pain despite adequate support or serial abnormal semen analysis in Tanner stage V boys is an indication for varicocelectomy. Artery and lymphatic sparing techniques (microscopic subinguinal or laparoscopic) are associated with the lowest risk of recurrence and complications.

CONCLUSIONS

Overtreatment and under treatment are medically and financially costly. Abnormal serial semen analysis with or without testicular hypotrophy is an indication for varicocele repair. If observation remains the treatment, followup with an adult urologist should be encouraged until paternity is achieved.

Increases in interleukin-6 and interferon-gamma levels is progressive in immature rats with varicocele

BACKGROUND

Pre-pubertal varicocele can result in hypotrophy of testes, progressive deterioration of Sertoli cells and spermatogonia cell number, decrease in seminiferous diameter and cause to sperm damage.

AIMS

Because of detrimental time-dependent effects of varicocele, this study describes the effects of varicocele on the levels of interleukin-6 (IL-6) and interferon-gamma in serum and testis tissue, seminiferous tubules diameter, number of Sertoli and spermatogonia cells, testis and epididymis weight and volume and sperm indices in immature rats.

METHODS

Thirty-six immature rats (5-6 weeks) were assigned into six groups: three sham groups and three varicocele groups. Serum, testis, and sperm samples were collected at 9, 11, and 13 weeks after induction of varicocele or sham operation to evaluate histological parameters and levels of cytokines.

RESULTS

Varicocele significantly caused an increase in serum and testis IL-6 and interferon-gamma, compared to related sham groups and previous varicocele groups (P < 0.05). Varicocele significantly decreased Sertoli cells and spermatogonia cell number with increasing varicocele time (P < 0.05). In the evaluation of seminiferous tubules diameter, the external, internal, and epithelium diameter were decreased compared to sham-related groups and previous varicocele groups. In the all varicocele groups, all types of sperm motility decreased compared to the related sham-operated group (P < 0.05).

CONCLUSIONS

This study suggests varicocele has a detrimental, time-dependent effect on cytokines levels and decreases Sertoli cells, spermatogonia cell number, seminiferous tubules diameter, and sperm indices.

Impact of varicocele on biological markers of gonadal function

PURPOSE

The aim of this study is to evaluate the potential effect of varicocele in the hormonal and clinical profile of adolescents.

METHODS

Twenty adolescents at Tanner stage 4-5 with left varicocele were studied and compared with a control group of 20 healthy adolescents. All patients underwent ultrasonographic testicular volumetry as well as hormonal evaluation of inhibin B, testosterone, baseline and gonadotropin-releasing hormone stimulated, follicle-stimulating hormone as well as luteinizing hormone. Statistical analysis was performed using the student's t test with p value <0.05 taken as statistical significant.

RESULTS

Patients with varicocele showed reduced levels of inhibin B compared to controls and a significant reduction in the testicular volume on the affected side. The response of luteinizing hormone to gonadotropin-releasing hormone stimulation was significantly higher in the varicocele group compared to the control group. Furthermore a significant inverse relationship of inhibin B compared to follicle-stimulating hormone was noted.

CONCLUSION

Serum inhibin B levels could represent a useful marker of Sertoli cell damage caused by varicocele.

Serum AMH in Physiology and Pathology of Male Gonads

AMH is secreted by immature Sertoli cells (SC) and is responsible for the regression of Müllerian ducts in the male fetus as part of the sexual differentiation process. AMH is also involved in testicular development and function. AMHs are at their lowest levels in the first days after birth but increase after the first week, likely reflecting active SC proliferation. AMH rises rapidly in concentration in boys during the first month, reaching a peak level at about 6 months of age, and then slowly declines during childhood, falling to low levels in puberty. Basal and FSH-stimulated levels of AMH, might become a useful predictive marker of the spermatogenic response to gonadotropic treatment in young patients with hypogonadotropic hypogonadism. After puberty, AMH is released preferentially by the apical pole of the SC towards the lumen of the seminiferous tubules, resulting in higher concentrations in the seminal plasma than in the serum. Defects in AMH production and insensitivity to AMH due to receptor defects result in the persistent Müllerian duct syndrome. A measurable value of AMH in a boy with bilateral cryptorchidism is predictive of undescended testes, while an undetectable value is highly suggestive of anorchia or ovaries, as would be the case in girls with female pseudohermaphroditism and pure gonadal dysgenesis. Lower serum AMH concentrations in otherwise healthy boys with cryptorchidism, who were compared with their age-matched counterparts with palpable testes, have been reported previously. AMH levels are higher in prepubertal patients with varicocele than in controls. This altered serum profile of AMH in boys with varicoceles may indicate an early abnormality in the regulation of the seminiferous epithelial function. Serum AMH is known to be valuable in assessing gonadal function. As compared to testing involving the administration of human chorionic gonadotropin, the measurement of AMH is more sensitive and equally specific. Measurement of AMH is very useful in young children, because serum gonadotropin concentrations in those who are agonadal are nondiagnostic in midchildhood and serum testosterone concentrations may fail to increase with provocative testing in children with abdominal testes.

Male hypogonadism: an extended classification based on a developmental, endocrine physiology-based approach

Normal testicular physiology results from the integrated function of the tubular and interstitial compartments. Serum markers of interstitial tissue function are testosterone and insulin-like factor 3 (INSL3), whereas tubular function can be assessed by sperm count, morphology and motility, and serum anti-Müllerian hormone (AMH) and inhibin B. The classical definition of male hypogonadism refers to testicular failure associated with androgen deficiency, without considering potential deficiencies in germ and Sertoli cells. Furthermore, the classical definition does not consider the fact that low basal serum testosterone cannot be equated to hypogonadism in childhood, because Leydig cells are normally quiescent. A broader clinical definition of hypogonadism that could be applied to male patients in different periods of life requires a comprehensive consideration of the physiology of the hypothalamic-pituitary-testicular axis and its disturbances along development. Here we propose an extended classification of male hypogonadism based on the pathophysiology of the hypothalamic-pituitary-testicular axis in different periods of life. The clinical and biochemical features of male hypogonadism vary according to the following: (i) the level of the hypothalamic-pituitary-testicular axis primarily affected: central, primary or combined; (ii) the testicular cell population initially impaired: whole testis dysfunction or dissociated testicular dysfunction, and: (iii) the period of life when the gonadal function begins to fail: foetal-onset or postnatal-onset. The evaluation of basal testicular function in infancy and childhood relies mainly on the assessment of Sertoli cell markers (AMH and inhibin B). Hypergonadotropism should not be considered a sine qua non condition for the diagnosis of primary hypogonadism in childhood. Finally, the lack of elevation of gonadotropins in adolescents or adults with primary gonadal failure is indicative of a combined hypogonadism involving the gonads and the hypothalamic-pituitary axis.

Serum inhibin B levels before and after varicocelectomy in early adolescence

BACKGROUND

Whereas no clear relationship has been observed between varicocelectomy and serum inhibin B levels in men, in adolescents comparison between inhibin B levels before and after varicocelectomy is lacking.

AIM

To evaluate the effect of varicocele surgical treatment on inhibin B levels in adolescents at the beginning of puberty compared to a group of healthy adolescents.

SUBJECTS AND METHODS

We studied 28 adolescents in Tanner 2 pubertal stage with a grade III left-sided varicocele (patients) compared to 13 age and pubertal stage-matched healthy adolescents (controls). All patients underwent blood tests to determine serum inhibin B levels before and 6 months after varicocelectomy by Palomo procedure. For comparison we investigated inhibin B levels in controls and repeated this test 6 months later. Testicular ultrasound was performed for patients only.

RESULTS

Baseline inhibin B concentrations of patients and controls were 109.90 ± 40.26 and 109.33 ± 38.34 pg/ml, respectively. No significant changes were observed in patients' inhibin B concentrations after varicocelectomy (116.00 ± 42.65 pg/ml), or in controls during the 6 months' follow-up (99.12 ± 30.09 pg/ml). Doppler examination after treatment shows a complete resolution of varicocele in all the patients without alterations in testicular parenchyma.

CONCLUSIONS

Varicocelectomy performed on adolescents at T2 pubertal stage might be useful to avoid alteration in inhibin B production and consequently in testicular function. Further studies are necessary to confirm the prognostic value of inhibin B levels and the benefit of early varicocelectomy in preserving the fertility of these adolescents.

Varicocele and infertility: why a prevention?

The varicocele is the abnormal dilation of the veins of the pampiniform plexus, resulting from an altered venous drainage, and it is considered one of the main causes of male infertility. In this paper we review the most recent observations on the histological, endocrinological, biochemical and clinical alterations reported in adolescents with left idiopathic varicocele. Data indicate that varicocele progressively impairs the reproductive function of the testis. Treatment could improve a number of such damages.

Seminiferous tubule function in delayed-onset X-linked adrenal hypoplasia congenita associated with incomplete hypogonadotrophic hypogonadism

OBJECTIVE

X-linked adrenal hypoplasia congenita (AHC, OMIM 300200) due to mutations in the DAX-1 gene is frequently associated to hypogonadotrophic hypogonadism (HHG, OMIM 238320). Clinical variants with delayed-onset have been recognized. The objective of this study is to assess Sertoli cell function throughout pubertal development in patients with childhood-onset AHC due to stop mutations in the DAX-1 gene.

DESIGN

Observational follow-up study of gonadotrophin pulsatility pattern, and serum levels of antimüllerian hormone and inhibin B through pubertal development in these patients.

PATIENTS

Three patients belonging to two families with AHC were included in this study.

MEASUREMENTS

The gonadotrophic pattern, serum inhibin B and antimüllerian hormone were determined in relation to clinical Tanner stage of pubertal development.

RESULTS

One patient showed a marked elevation in serum FSH concomitantly with low inhibin B and antimüllerian hormone levels, indicating a primary testicular dysfunction. The other two patients showed a gonadotrophic pattern of HHG, and their serum levels of inhibin B and antimüllerian hormone also reflected a moderate primary testicular dysfunction. The three patients were azoospermic.

CONCLUSIONS

These cases give further insight into the clinical spectrum of phenotypes of the hypothalamic-pituitary-gonadal axis in patients with variants in hypogonadism associated with childhood-onset X-linked AHC due to DAX-1 mutations.

Establishment of testicular endocrine function impairment during childhood and puberty in boys with Klinefelter syndrome

OBJECTIVE

To precisely characterize the chronology of testicular endocrine function impairment during childhood and adolescence in patients with Klinefelter syndrome. Design Retrospective chart review. Patients A total of 29 boys with Klinefelter syndrome with up to 12.3 years follow-up.

MEASUREMENTS

Clinical features and serum hormone levels were analysed during follow-up.

RESULTS

Of the 29 patients, 16 were prepubertal and 13 had already entered puberty at their first visit. Fifteen patients were followed up through late puberty. Before puberty, LH, FSH, testosterone, anti-Müllerian hormone (AMH) and inhibin B were within the expected range in almost all cases. However, levels of the inhibin alpha-subunit precursor Pro-alphaC were in the lowest levels of the normal range in most cases. During puberty, FSH levels increased earlier and more markedly than LH. Inhibin B and AMH declined to abnormally low or undetectable levels in advanced pubertal stages. Although testosterone and Pro-alphaC levels were within the reference ranges in most cases, they were abnormally low for the observed LH values.

CONCLUSIONS

In Klinefelter syndrome, a mild Leydig cell dysfunction is present from early childhood in most cases and persists throughout puberty. Sertoli cell function is normal until mid puberty, when a dramatic impairment is observed.

Testicular adrenal rest tumors and Leydig and Sertoli cell function in boys with classical congenital adrenal hyperplasia

CONTEXT

Infertility observed in adult males with congenital adrenal hyperplasia (CAH) has been associated with testicular adrenal rest tumors (TART) that may originate during childhood.

OBJECTIVE

Our objective was to describe the prevalence of TART and Sertoli and Leydig cell function in a group of boys aged 2-10 yr with CAH and to compare prevalence with that of a control group.

DESIGN

From August 2005 to January 2007, 19 patients with classical CAH (CAH group) were referred from seven endocrinology centers.

METHODS

We studied 19 subjects in the CAH group and, as a control group, 13 boys from the community that did not have testicular diseases. A complete physical exam was performed. High-resolution ultrasound was used to determine TART prevalence. Inhibin B and anti-Müllerian hormone were used as Sertoli cell markers. The ratio between basal testosterone levels and testosterone levels 72 h after beta-human chorionic gonadotropin (5000 U/m2) treatment [(T72- T0)/T0] was used to evaluate Leydig cell response.

RESULTS

CAH and control groups were comparable in chronological age (5.9 vs. 5.6 yr; P = 0.67) and bone age/chronological age ratio (1.09 vs. 1.03; P = 0.09). TART prevalence was four of 19 (21%) in the CAH group. Lower values for inhibin B (49.2. vs. 65.2 pg/ml; P = 0.018), anti-Müllerian hormone (70.1 vs. 94.2 ng/ml; P = 0.002), and (T72- T0)/T0 (5.6 vs. 13.6; P < 0.01) were observed in the CAH group.

CONCLUSION

TART in prepubertal males with classic CAH could be found during childhood. We also report differences in markers of gonadal function in a subgroup of patients, especially in those with inadequate control.

Altered serum inhibin b levels in adolescents with varicocele

BACKGROUND/PURPOSE

Different studies have evaluated testicular hormonal dysfunction in adolescent varicocele but with variable results. Recently, inhibin B has been proposed as a marker for spermatogenesis and Sertoli cell function. The aim of the present study was to study in a homogeneous cohort of adolescents inhibin B and other hormones to detect whether untreated varicocele may be associated with any modifications of these factors.

METHODS

Sixteen adolescents (mean age, 14.5 +/- 1.0 years), at Tanner stages 4 to 5 with grade II or III left-sided varicocele, underwent hormonal evaluation of inhibin B, basal testosterone, and both baseline and GnRH stimulated FSH and LH levels. Thirteen unaffected adolescents of age-matched and pubertal development were used as controls.

RESULTS

Patients with varicocele showed a significant reduction in the testicular volume of the affected side (13.3 +/- 4.1 vs 15.8 +/- 4.8 mL; P = .002) and significant reduced levels of inhibin B compared with controls (271.9 +/- 70.2 vs 327.1 +/- 34.9 pg/mL; P = .042). Inhibin B levels were significantly correlated with testes volume (r = 0.62; P = .0097). Other hormonal parameters were similar in both varicocele and control groups.

CONCLUSION

Inhibin B is reduced in adolescents with untreated varicocele, and it is positively correlated with testicular volume. This could be an early marker for Sertoli cell damage, with possible implications for spermatogenesis and could represent a new indication for varicocele repair.

Carbohydrate complexity and proportions of serum FSH isoforms in the male: lectin-based studies

FSH is synthesized and secreted in multiple molecular forms with different oligosaccharide structures which are needed for full expression of biological activity. GnRH and sex steroids modulate oligosaccharide structure and composition. In the present study we have assessed the carbohydrate complexity and proportion of circulating FSH isoforms during puberty, aging and after androgen administration to pubertal anorchid boys. Preparative isoelectrofocusing and lectin chromatography were used to isolate FSH isoforms on the basis of charge and internal carbohydrate complexity. Differences in sialic acid content and a progressive increase of isoforms bearing highly branched oligosaccharides were found during puberty. Less acidic, more bioactive FSH isoforms, secreted at mid-puberty may modulate important maturational events in the Sertoli cell population. Androgen administration to pubertal anorchid boys favoured the secretion of this type of isoforms. In adult men, the predominance of FSH isoforms bearing complex type oligosaccharides remained unchanged until very advanced age. These results show that the predominance of FSH isoforms bearing fully processed oligosaccharides in circulation may contribute to the development and maintenance of seminiferous epithelium function in men.

Relationship between male reproductive hormones, sperm DNA damage and markers of oxidative stress in infertility

This study investigated the relationship between male reproductive hormones and sperm DNA damage and markers of oxidative stress in men undergoing infertility evaluation for male factor (n = 66) and non-male factor (n = 63) infertility. Semen samples were analysed for DNA fragmentation index (DFI). Serum samples were analysed for FSH, inhibin B, anti-Müllerian hormone (AMH), testosterone and total antioxidant capacity (TAC). Serum inhibin B was significantly lower in the male factor group compared with the non-male factor group. Inhibin B showed a positive correlation with sperm concentration and motility, and serum AMH showed a positive correlation with sperm concentration and semen volume. DFI was 3-fold higher in the male factor group and showed a negative correlation with sperm motility. Blood plasma TAC was negatively related to sperm concentration. The results confirm that AMH and inhibin B are markers of Sertoli cell function. Sperm DNA damage is moderately increased in male factor infertility, and is negatively associated with sperm motility. A negative association between antioxidant activity and sperm concentration suggests that even minimal oxidative stress may influence sperm concentration. However, there was no significant relationship between hormone concentrations, sperm DNA damage and total antioxidant capacity, suggesting other mechanisms for sperm dysfunction.