Cryptorchidism --disease or symptom?

Cryptorchidism and puberty

Cryptorchidism is the condition in which one or both testes have not descended adequately into the scrotum. The congenital form of cryptorchidism is one of the most prevalent urogenital anomalies in male newborns. In the acquired form of cryptorchidism, the testis that was previously descended normally is no longer located in the scrotum. Cryptorchidism is associated with an increased risk of infertility and testicular germ cell tumors. However, data on pubertal progression are less well-established because of the limited number of studies. Here, we aim to review the currently available data on pubertal development in boys with a history of non-syndromic cryptorchidism-both congenital and acquired cryptorchidism. The review is focused on the timing of puberty, physical changes, testicular growth, and endocrine development during puberty. The available evidence demonstrated that the timing of the onset of puberty in boys with a history of congenital cryptorchidism does not differ from that of non-cryptorchid boys. Hypothalamic-pituitary-gonadal hormone measurements showed an impaired function or fewer Sertoli cells and/or germ cells among boys with a history of cryptorchidism, particularly with a history of bilateral cryptorchidism treated with orchiopexy. Leydig cell function is generally not affected in boys with a history of cryptorchidism. Data on pubertal development among boys with acquired cryptorchidism are lacking; therefore, more research is needed to investigate pubertal progression among such boys.

Comparative genomics reveals molecular mechanisms underlying health and reproduction in cryptorchid mammals

BACKGROUND

Mammals have wide variations in testicular position, with scrotal testes in some species and ascrotal testes in others. Although cryptorchidism is hazardous to human health, some mammalian taxa are natural cryptorchids. However, the evolution of testicular position and the molecular mechanisms underlying the maintenance of health, including reproductive health, in ascrotal mammals are not clear.

RESULTS

In the present study, comparative genomics and evolutionary analyses revealed that genes associated with the extracellular matrix and muscle, contributing to the development of the gubernaculum, were involved in the evolution of testicular position in mammals. Moreover, genes related to testicular position were significantly associated with spermatogenesis and sperm fertility. These genes showed rapid evolution and the signature of positive selection, with specific substitutions in ascrotal mammals. Genes associated with testicular position were significantly enriched in functions and pathways related to cancer, DNA repair, DNA replication, and autophagy.

CONCLUSIONS

Our results revealed that alterations in gubernaculum development contributed to the evolution of testicular position in mammals and provided the first support for two hypotheses for variation in testicular position in mammals, the "cooling hypothesis", which proposes that the scrotum provides a cool environment for acutely heat-sensitive sperm and the "training hypothesis", which proposes that the scrotum develops the sperm by exposing them to an exterior environment. Further, we identified cancer resistance and DNA repair as potential protective mechanisms in natural cryptorchids. These findings provide general insights into cryptorchidism and have implications for health and infertility both in humans and domestic mammals.

Rapid evolution and molecular convergence in cryptorchidism-related genes associated with inherently undescended testes in mammals

BACKGROUND

The mammalian testis is an important male exocrine gland and spermatozoa-producing organ that usually lies in extra-abdominal scrotums to provide a cooler environment for spermatogenesis and sperm storage. Testicles sometimes fail to descend, leading to cryptorchidism. However, certain groups of mammals possess inherently ascrotal testes (i.e. testes that do not descend completely or at all) that have the same physiological functions as completely descended scrotal testes. Although several anatomical and hormonal factors involved in testicular descent have been studied, there is still a paucity of comprehensive research on the genetic mechanisms underlying the evolution of testicular descent in mammals and how mammals with ascrotal testes maintain their reproductive health.

RESULTS

We performed integrative phenotypic and comparative genomic analyses of 380 cryptorchidism-related genes and found that the mammalian ascrotal testes trait is derived from an ancestral scrotal state. Rapidly evolving genes in ascrotal mammals were enriched in the Hedgehog pathway-which regulates Leydig cell differentiation and testosterone secretion-and muscle development. Moreover, some cryptorchidism-related genes in ascrotal mammals had undergone positive selection and contained specific mutations and indels. Genes harboring convergent/parallel amino acid substitutions between ascrotal mammals were enriched in GTPase functions.

CONCLUSIONS

Our results suggest that the scrotal testis is an ancestral state in mammals, and the ascrotal phenotype was derived multiple times in independent lineages. In addition, the adaptive evolution of genes involved in testicular descent and the development of the gubernaculum contributed to the evolution of ascrotal testes. Accurate DNA replication, the proper segregation of genetic material, and appropriate autophagy are the potential mechanisms for maintaining physiological normality during spermatogenesis in ascrotal mammals. Furthermore, the molecular convergence of GTPases is probably a mechanism in the ascrotal testes of different mammals. This study provides novel insights into the evolution of the testis and scrotum in mammals and contributes to a better understanding of the pathogenesis of cryptorchidism in humans.

Is Testicular Torsion a Real Problem in Pediatric Patients With Cryptorchidism?

Purpose: To present management and outcomes of patients with cryptorchidism suffering from testicular torsion. Methods: This is a retrospective review of pediatric patients with torsion of undescended testes, who were treated between 2009 and 2019. We recorded: the age, symptoms, duration of torsion, results of physical examination, surgery findings, and additional treatment. Additionally, an extensive online literature search, from 2015-2020, was performed to identify other similar case series. Results: We identified 9 boys with torsion of the undescended gonad, which represented 4.7% of all 192 boys with testicular torsion. The mean age of boys with torsion of undescended testis was 8.7 years. The mean duration of symptoms in our study group was long and it was up to 28.5 h. All patients had inguinal canal exploration. In eight cases, testicular necrosis and primary orchidectomy was performed. Furthermore, 45 cases were identified in the literature and reviewed. Conclusion: According to clinical experience and available studies, torsion of male undescended gonads is a comparatively rare condition. Nevertheless, diagnosis is still delayed and connected with inevitable orchidectomy.

Frequency of revision orchidopexy in Australia 1995-2014

BACKGROUND/AIM

International criteria currently suggest orchidopexy at 6-12months for congenital undescended testis (UDT). Some children require repeat orchidopexy for recurrent UDT. This study aimed to assess practice in Australia over a 20-year period.

METHODS

We examined 20years of Australian orchidopexy data (1995-2014) from the Department of Human Services to explore the national revision orchidopexy rates over time.

RESULTS

The total number of orchidopexy revisions was 890 over 20years compared with 25,984 primary operations. More than 50% of all primary and revision orchidopexies in 0-14year-old boys were performed in major population centers of NSW and Victoria (which hold 52% male population of same age), with a small number of revisions on 15-24year-old males. The incidence of revision orchidopexy significantly decreased over the 20-year period in boys ages 0-14years old, from 276 operations between 1995 and 1999 decreasing to 165 operations between 2010 and 2014 (-53%), compared to a population increase of +15% (p<0.05).

CONCLUSION

These data demonstrate a decrease in revision orchidopexy since 1995, which may be related to change in referral practice with more children undergoing orchidopexy (primary and revision) by pediatric surgeons over the 20-year period.

LEVEL OF EVIDENCE

Level IV.

TYPE OF STUDY

Therapeutic Case Series with no Comparison Group.

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.

Undescended testes: an update

PURPOSE OF REVIEW

This article summarizes the latest evidence on the risk factors, management and outcomes of undescended testes (UDTs).

RECENT FINDINGS

UDTs remain common, with increasing evidence that acquired UDT or the ascending testis syndrome should be considered part of the spectrum of this disease. Prompt diagnosis and early referral for surgical evaluation and treatment would seem most likely to result in an optimal functional and cosmetic outcome. Hormonal treatment, rather than orchidopexy, remains popular in some centers, despite a lack of good evidence to support its efficacy, although it may have an important adjunct role in optimizing fertility. Although often performed, ultrasound does not generally assist in the diagnosis and management of UDT, with enhanced education of primary care physicians more likely to facilitate early referral. The testis, rather than quiescent, appears biologically active in the male infant, with increasing evidence of an adverse impact on future spermatogenesis and fertility in men with a UDT.

SUMMARY

Male infants with a UDT should be diagnosed and referred early for surgical evaluation. It seems likely that the optimal timing for surgery should be before the boy's first birthday. There remains a need for high-quality, long-term outcomes data to guide optimal management.

The separation of the epididymis and the abnormal attachment of the gubernaculum cause undescendence in the rat testes

PURPOSE

Epididymal anomalies are common in cryptorchid patients. This led us to consider that anomalies of the epididymis, to which the gubernaculum is attached, or abnormal attachment of the cranial end of the gubernaculum, could lead to cryptorchidism.

METHODS

Twenty-eight male Sprague-Dawley rats were divided into two groups: In Group 1 rats (n = 14), the epididymis was isolated from the testis, and in Group 2 rats (n = 14), the gubernaculum was isolated from the epididymis and re-attached to the tail of the epididymis. In both groups, the non-operated testes were used as the control.

RESULTS

In Group 1, cryptorchidism rates were 1/14 in the control testes and 8/14 in the operated testes (p < 0.01). In Group 2, cryptorchidism rates were 0/13 in the control testes and 6/13 in the operated testes (p < 0.01).

CONCLUSION

Cryptorchidism was seen when the epididymis was loosely or non-connected to the testis and the gubernaculum was attached solely to the epididymis (mimicking anomalies of ductal fusion) and when the gubernaculum was attached to the tail of the epididymis (mimicking anomalies of ductal suspension). Therefore epididymal anomalies and abnormal attachment of the gubernaculum may play a role in the undescendence of the testes in the rats.

Causes, effects and molecular mechanisms of testicular heat stress

The process of spermatogenesis is temperature-dependent and occurs optimally at temperatures slightly lower than that of the body. Adequate thermoregulation is imperative to maintain testicular temperatures at levels lower than that of the body core. Raised testicular temperature has a detrimental effect on mammalian spermatogenesis and the resultant spermatozoa. Therefore, thermoregulatory failure leading to heat stress can compromise sperm quality and increase the risk of infertility. In this paper, several different types of external and internal factors that may contribute towards testicular heat stress are reviewed. The effects of heat stress on the process of spermatogenesis, the resultant epididymal spermatozoa and on germ cells, and the consequent changes in the testis are elaborated upon. We also discuss the molecular response of germ cells to heat exposure and the possible mechanisms involved in heat-induced germ cell damage, including apoptosis, DNA damage and autophagy. Further, the intrinsic and extrinsic pathways that are involved in the intricate mechanism of germ cell apoptosis are explained. Ultimately, these complex mechanisms of apoptosis lead to germ cell death.