Compensatory function of the remaining testis is dissociated in boys and adolescents with monorchidism

Is anti-müllerian hormone useful for monorchidism diagnosis in the tomcat?

Monorchidism is an uncommon condition in tomcats, defined by the congenital absence of one of the testicles. Due to the lack of information regarding possible biomarkers, most monorchidism cases require laparotomy in order to differentiate it from cryptorchidism. Human data suggest that monorchid patients have lower serum anti-Müllerian hormone (AMH) levels when compared to cryptorchids, premises that has been also scrutinized in veterinary medicine. Here, we describe a case of monorchidism in a tomcat, focusing on the clinical findings and the dynamics of AMH serum levels before and after the removal of the singularly identified testicle. To contribute to the limited knowledge of AMH levels across different reproductive statuses in tomcats, the findings from this monorchid case were compared to values obtained from two cryptorchid tomcats (one unilateral and one bilateral), three intact tomcats, and three castrated tomcats. In addition, clinical, histopathological and ultrasound examinations were conducted in all tomcats. The AMH levels in the monorchid tomcat revealed a consistent decrease after surgery, from 27.3 ± 0.2 ng/ml when the testicle was still present, to 2.3 ± 0.2 ng/ml 1 week later, and further decreasing below the detection limit (<0.15 ng/ml) for the last 2 weeks of the trial, matching the AMH level of the castrated male. AMH serum levels of the bilateral and unilateral cryptorchid tomcat (22.5 ± 0.3 ng/ml; 24.1 ± 0.2 ng/ml) were in agreement with those of the three intact males (19.1 ± 2.2 ng/ml) and the monorchid prior to surgery. AMH testing effectively confirmed the absence of testicular tissue after unilateral orchiectomy in a monorchid tomcat but did not differentiate between monorchidism and cryptorchidism. To our knowledge, this is the first case of monorchidism in tomcats, in which AMH levels before and after surgery have been determined.

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.

Gonadotropins in the Management of Couple Infertility: Toward the Rational Use of an Empirical Therapy

Although epidemiology shows that both men and woman can experience infertility, the female partner usually experiences most of the diagnostic and therapeutic burden. Thus, management of couple infertility is a unique example of gender inequality. The use of exogenous gonadotropins in assisted reproductive technology (ART) to induce multifollicular growth is well consolidated in women, but the same is not done with the same level of confidence and purpose in infertile men. Indeed, the treatment of idiopathic male infertility is based on an empirical approach that involves administration of the follicle-stimulating hormone (FSH) in dosages within the replacement therapy range. This treatment has so far been attempted when the endogenous FSH serum levels are within the reference ranges. According to the most recent evidence, a "substitutive" FSH administration may not be effective enough, while a stimulatory approach could boost spermatogenesis over its basal levels without adverse extragonadal effects. This article aims to describe the rationale behind the empirical application of gonadotropins in couple infertility, highlighting the need for a change in the therapeutic approach, especially for the male partner.

Age-dependent effect on contralateral testicular compensation after testicular loss

OBJECTIVE

To study compensatory changes in testicular growth and the hormonal axis after unilateral orchiectomy in a neonatal, prepubertal, and pubertal/adult murine model. This is the first study to use a neonatal mouse survival surgery model.

DESIGN

A laboratory-based study examining a control, neonatal, prepubertal, and pubertal/adult mouse model.

SETTING

University-based basic science research laboratory.

ANIMALS

Control, neonatal (2-4 days of life), prepubertal (12-21 days of life), and pubertal/adult (42-44 days of life) C57BL/6 mouse models.

INTERVENTION

Unilateral orchiectomy in the neonatal, prepubertal, and pubertal/adult mouse models at their respective ages.

MAIN OUTCOME MEASURES

Body and testis weight and testicular length in the long axis were measured in a blinded fashion. In a similar way, testosterone, luteinizing hormone (LH), and follicle-stimulating hormone were assessed.

RESULTS

Testes from neonatal and prepubertal mice weighed more (110.5, 12.2 and 103.0, 7.2 mg, respectively) than the control mice (91, 11.9 mg). There was no difference between the postpubertal group and the control group. The degree of compensatory hypertrophy was greater in the neonatal group but not in the prepubertal group when compared with the postpubertal group. Differences in follicle-stimulating hormone and testosterone were not statistically significant between the experimental and control arms. LH was significantly elevated in all experimental groups compared with the control.

CONCLUSIONS

This is the first study to assess testicular compensatory hypertrophy using a neonatal mouse survival surgery model. Testicular hypertrophy occurs when unilateral loss occurs before puberty, but not in adulthood in mice. Earlier testis loss may contribute to a greater degree of growth. Functionally, the unilateral testis can maintain eugonadal testosterone levels, but higher levels of LH are required after hemicastration to sustain eugonadal testosterone levels.

Serial Inhibin B Measurements in Boys with Congenital Monorchism Indicate Compensatory Testicular Hypertrophy in Early Infancy

AIM

 Congenital monorchism is considered a condition in which an initially normal testis has existed but subsequently atrophied and disappeared due to a third trimester catastrophe (presumably torsion). Since inhibin B concentrations appear related to Sertoli and germ cells number, we evaluated pre- and postoperative inhibin B of boys with congenital monorchism to determine whether the well-known hypertrophy of the contralateral testis was reflected in inhibin B concentrations.

MATERIALS AND METHODS

 Twenty-seven boys consecutively diagnosed with congenital monorchism (median age 12 months) underwent follow-up with reproductive hormones 1 year postoperatively (median age 25 months). The results were compared with inhibin B of 225 boys with congenital nonsyndromic unilateral cryptorchidism, by converting values to multiple of the median (MoM) for age in normal boys.

RESULTS

 Ten boys (37%) had blind-ending vessels and ductus deferens (vanished testis) and the remaining (63%) had testicular remnants. At the time of diagnostic procedure, monorchid boys did not have significantly lower inhibin B (median 114, range 20-208) than unilateral cryptorchid boys (136, 47-393) (p = 0.27). During follow-up, MoM values of inhibin B increased in monorchid boys (median 0.59 to 0.98) and in unilateral cryptorchid boys (0.69 to 0.89) (both p < 0.0001). Compared with the concentration at surgery, an additional 44% monorchid boys had inhibin B MoM values higher than 1.0, whereas only additional 23% of unilateral cryptorchid boys exhibited such values (p = 0.04).

CONCLUSION

 Generally, inhibin B MoM values were normalized during follow-up in boys with congenital monorchism, reflecting compensatory hypertrophy within the first 2.5 years of life. The compensatory capacity to increase was better in monorchism than in unilateral cryptorchidism.

Damaged/missing proximity sensor induces screen mistouch when answering calls: Prediction of smartphone answering status by posture data

When the proximity sensor of a smartphone is impaired, it would easily lead to screen mistouch during conversation, which will significantly affect the user experience. However, there are relatively few studies that have been focused on the quality of user experience following sensor impairment. The purpose of this study was to compare and evaluate different machine learning models in forecasting the user’s posture during a phone call, thereby providing a compensation approach for detecting proximity to the human ear during a phone call following sensor damage. The built-in accelerometer sensors of smartphones were employed to collect posture data while users were employing their smartphones. Three main postures (holding, moving and answering) were identified; the posture data were obtained through training and prediction using five machine learning models. The results showed that the model that utilized triaxial data had better prediction accuracy than the model that used single-axis data. Furthermore, models with time-domain features had a higher accuracy rate. Among the five models, neural networks had the best prediction accuracy (0.982). The proposed approach could be of immense benefit to the users following proximity sensor damage, and would be advantageous in the design of the smartphone, particularly in the early stages of the design process.

Adjuvant pharmacological and surgical therapy for testicular torsion: Current state of the art

INTRODUCTION

Although the consequences of testicular torsion (TT) have been recognized for centuries, little progress has been made to improve outcomes beyond those seen with timely scrotal exploration. Even with testicular salvage, ischemia/reperfusion injury cause significant atrophy and functional impairment. Recent efforts have sought to identify adjuvant pharmacological or surgical interventions that may attenuate these consequences. In this review, we assess the evidence supporting clinical use of these nascent interventions.

METHODS

We conducted a review of the literature published from 2000 to 2020, using the search terms "torsion", "testicular", "reperfusion", "ischemia", and "injury". Clinical and laboratory research focused on adjuvant pharmacological and surgical techniques mitigating torsion-associated injury in animal models and humans were identified. We recorded intervention timing/dose/route, and outcome timing/category through biomarkers of reperfusion injury, histology, and hormonal/reproductive function.

RESULTS

Fifty-four FDA-approved agents, plus 52 herbal/investigational drugs, were reported in animal TT models. In every study, the investigated agents showed beneficial effects on measured endpoints compared to controls. Despite these universally promising animal findings, no pharmacological trials in humans were reported. Surgical techniques studied in animal models included decompression (tunica albuginea incision, TAI), "ischemic conditioning", and hypothermia. Only three human studies on surgical adjuvant maneuvers have been reported, all involving TAI; these showed potential benefit, but the level of evidence is low.

CONCLUSION

There is preliminary evidence that adjuvant treatments may mitigate the effects of ischemia/reperfusion injury. However, the pool of investigated pharmacological agents is wide, yet remarkably shallow; most compounds have been reported in a single animal study. To advance this field, a mechanism-based approach should be used to select promising agents that can be tested systematically. This will determine treatment parameters that maximize safety, efficacy, and tolerability. Only then is it possible to move toward human trials. Adjuvant surgical methods such as TAI show promise in humans but require more robust clinical evaluation.

Effect of Pediatric Testicular Torsion on Testicular Function in the Short Term

PURPOSE

To evaluate short-term testicular outcome after torsion in children.

METHODS

Fifty-four children and adolescents were evaluated after 6 months of the operation for testicular torsion. Testicular volume was measured and circulating Inhibin B, FSH, LH and testosterone levels were checked.

RESULTS

Delay from the onset of symptoms to surgery was shorter in the orchidopexy group (n = 47), than in the orchiectomy group (n = 7, p = 0.001). In the orchidopexy group, the median volume of the affected testis was 83% (IQR 43-104) of the contralateral testis (p = 0.002). The plasma hormone levels in orchidopexy and orchiectomy groups were: 148 ng/l (IQR 108-208) vs. 129 ng/l (IQR, 123-138, p = 0.269) for Inhibin B; 4.5 IU/L (IQR2.6-6.9) vs. 11.7 IU/L (IQR 4.3-12.8, p = 0.037) for FSH; 2.9 IU/L (IQR 1.3-3.7) vs. 4.8 (IQR 3.0-5.6, p = 0.066) for LH; and 13.6 nM (IQR 6.5-18.0) vs. 14.5 nM (IQR 6.7-15.9, p = 0.834) for testosterone. The association between FSH, LH as well as testosterone levels was most clear with the volume of the contralateral testis (Rho = 0.574, p < 0.001, Rho = 0.621, p = 0.001 and Rho 0.718, p < 0.001 respectively).

CONCLUSIONS

Testicular function is mainly dependent on the volume of contralateral testicle after testicular torsion. However, testis preserving surgery tends to maintain better function than orchiectomy.

TYPE OF STUDY

Retrospective review.

LEVEL OF EVIDENCE

III.

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.

Comparing the role of anti-Müllerian hormone as a marker of FSH action in male and female fertility

INTRODUCTION

Originally limited to the assessment of disorders of sex development, anti-Müllerian hormone (AMH) measurement has more recently been extended to several conditions affecting the reproductive axis in males and females. Follicle-stimulating hormone (FSH) regulation of gonadal function has been extensively studied, but its role on AMH production has been explored only recently.

AREAS COVERED

We addressed the relationship between FSH action on the gonads and the usefulness of AMH as a marker in conditions affecting the reproductive axis.

EXPERT OPINION

Sertoli cells are the most active cell population in the prepubertal testis. Serum AMH is an excellent marker of FSH action on Sertoli cell proliferation and function in patients with hypogonadotropic hypogonadism. Low serum AMH is expected to predict low sperm production and prompts initial FSH treatment followed by human chorionic gonadotropin (hCG) or luteinizing hormone (LH) addition. Gonadotropin treatment may be more effective if installed to mimic the postnatal activation stage of the hypothalamic-pituitary-testicular axis. In females, AMH secretion by small antral follicles is stimulated by FSH. Elevated AMH indicates increased follicle numbers and should be considered as a potential contraindication of gonadotropin treatment in infertile patients due to an increased risk of developing ovarian hyperstimulation syndrome.

Male Central Hypogonadism in Paediatrics - the Relevance of Follicle-stimulating Hormone and Sertoli Cell Markers

The definition of male hypogonadism, used in adult endocrinology, is not fully applicable to paediatrics. A clear understanding of the developmental physiology of the hypothalamic-pituitary-testicular axis is essential for the comprehension of the pathogenesis of hypogonadal states in boys and for the establishment of adequate definitions and classifications in paediatric ages. This is particularly true for central hypogonadism, usually called hypogonadotropic in adults. Because childhood is a period characterised by a physiological state of low gonadotropin and testosterone production, these markers of hypogonadism, typically used in adult endocrinology, are uninformative in the child. This review is focused on the physiological importance of prepubertal Sertoli cell markers - anti-Müllerian hormone (AMH) and inhibin B - and of the intratesticular actions of follicle-stimulating hormone (FSH) and testosterone during early infancy and the first stages of pubertal development. We discuss the role of FSH in regulating the proliferation of Sertoli cells - the main determinant of prepubertal testicular volume - and the secretion of AMH and inhibin B. We also address how intratesticular testosterone concentrations have different effects on the seminiferous tubule function in early infancy and during pubertal development.

The Nonpalpable Testis: A Narrative Review

PURPOSE

While the nonpalpable testis represents a small portion of all cryptorchid testes, it remains a clinical challenge for pediatric urologists. Controversy exists surrounding the best evaluation and management of this entity. In this review we update what is known about the nonpalpable testis, including the etiology, preoperative evaluation and best surgical management as well as novel techniques and ongoing controversies.

MATERIALS AND METHODS

We searched PubMed® and MEDLINE® from January 2000 to January 2017 using relevant key terms. Of 367 articles 115 were considered for inclusion based on a priori design. Using a narrative review format, an update on the evaluation and management of the nonpalpable testis including novel concepts and techniques was synthesized.

RESULTS

The nonpalpable testis should be evaluated by physical examination only. Imaging is not indicated for routine cases. The optimal surgical approach and technique remain debatable but several novel techniques have been described. Due to the rarity of the nonpalpable testis, randomized controlled trials and other quality comparisons are difficult. Therefore, management remains controversial.

CONCLUSIONS

Evaluation and management of the nonpalpable testis remain difficult, and some aspects are still debated. Future research should focus on multi-institutional collaborative trials to determine the optimal operative management.

Anti-Müllerian hormone as a marker of steroid and gonadotropin action in the testis of children and adolescents with disorders of the gonadal axis

In pediatric patients, basal testosterone and gonadotropin levels may be uninformative in the assessment of testicular function. Measurement of serum anti-Müllerian hormone (AMH) has become increasingly widespread since it provides information about the activity of the male gonad without the need for dynamic tests, and also reflects the action of FSH and androgens within the testis. AMH is secreted in high amounts by Sertoli cells from fetal life until the onset of puberty. Basal AMH expression is not dependent on gonadotropins or sex steroids; however, FSH further increases and testosterone inhibits AMH production. During puberty, testosterone induces Sertoli cell maturation, and prevails over FSH on AMH regulation. Therefore, AMH production decreases. Serum AMH is undetectable in patients with congenital or acquired anorchidism, or with complete gonadal dysgenesis. Low circulating levels of AMH may reflect primary testicular dysfunction, e.g. in certain patients with cryptorchidism, monorchidism, partial gonadal dysgenesis, or central hypogonadism. AMH is low in boys with precocious puberty, but it increases to prepubertal levels after successful treatment. Conversely, serum AMH remains at high, prepubertal levels in boys with constitutional delay of puberty. Serum AMH measurements are useful, together with testosterone determination, in the diagnosis of patients with ambiguous genitalia: both are low in patients with gonadal dysgenesis, including ovotesticular disorders of sex development, testosterone is low but AMH is in the normal male range or higher in patients with disorders of androgen synthesis, and both hormones are normal or high in patients with androgen insensitivity. Finally, elevation of serum AMH above normal male prepubertal levels may be indicative of rare cases of sex-cord stromal tumors or Sertoli cell-limited disturbance in the McCune Albright syndrome.