Inhibin B and anti-Müllerian hormone in spermatic vein of subfertile men with varicocele

Insight into inflammation involvement in varicocele: A narrative review

BACKGROUND

Varicocele is one of the main causes of male infertility. Although the pathophysiology mechanism of varicocele is very well described and understood, there are some unanswered questions that remains unknown. Some studies have previously described the state of testicular inflammation and sperm in animal models, especially the mouse model, and the seminal plasma of men with varicocele, with or without changes in semen parameters.

METHODS OF STUDY

This review intended to verify the role of inflammatory mechanism in varicocele, using clinical studies as well as animal model studies on the effect of inflammation caused by varicocele on the function of testicular somatic and germ cells.

RESULTS

In-vivo studies confirmed whether anti-inflammatory molecules could treat the semen of men with varicocele and rats with varicocele. The use of different anti-inflammatory agents in mouse model studies provided a new perspective for future clinical studies to investigate the effect of concurrent treatment with surgery to improve surgical outcomes.

CONCLUSION

Similar to animal model studies, previously conducted clinical trials have demonstrated the effectiveness of anti-inflammatory therapy in varicocele patients. However, clinical trials using anti-inflammatory are needed to be conducted agents to evaluate different aspects of this therapeutical approach in varicocele patients.

Varicoceles in Men With Non-obstructive Azoospermia: The Dilemma to Operate or Not

The knowledge on male reproduction is constantly expanding, especially in treating infertility due to non-obstructive azoospermia (NOA). Varicocele is occasionally diagnosed in a subpopulation of males with NOA. Varicocele repair in NOA-men may contribute to the reappearance of spermatozoa in semen. However, spontaneous pregnancies are observed in only a small percentage of NOA-men post-varicocelectomy. Additionally, it has been reported that the repair of varicocele in NOA-men (before the performance of sperm retrieval techniques) may increase the testicular sperm recovery rate. In addition, it increases the pregnancy rate in intracytoplasmic sperm injection (ICSI) programs in NOA-men without spermatozoa in the semen post-varicocelectomy. In addition, to the improvement in Sertoli cellular secretory function, varicocelectomy may increase the secretory function of Leydig cells, which subsequently results in improved androgen production, raising the probability to negate the need for testosterone replacement therapy in cases of late-onset hypogonadism. On the other hand, the benefit of varicocelectomy in patients with NOA is still debatable. The current review study aims to provide a critical and extensive review of varicocele repair in males with NOA. This study additionally focuses on the impact of varicocele repair on sperm retrieval rates and its influence on the ICSI outcomes for those couples who remain negative for spermatozoa in their semen samples post-varicocelectomy.

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.

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.

Varicocele repair in the era of modern assisted reproductive techniques

PURPOSE OF REVIEW

This review looks at the literature on varicocele repair and its effect on assisted reproductive techniques. The effects of varicocele correction on improved sperm production have been well documented with semen analysis data. What remain to be elucidated are the causes of the varicocele effect and how correction of the resultant pathophysiology may affect the outcomes of modern assisted reproductive technology.

RECENT FINDINGS

Basic science research shows us that varicoceles exert deleterious effects on Leydig cells, Sertoli cells, and germ cells via very different mechanisms. The effects of varicocele correction on the reproductive potential of sperm are less well understood. Clinical research has shown improved semen parameters, DNA integrity, and assisted reproductive technology outcomes after varicocele repair.

SUMMARY

Varicocele correction presents a possible method to optimize a couples' reproductive potential or decrease the need for complex assisted reproductive technology.

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.