The regulation of testicular descent and the effects of cryptorchidism

Diagnoses and Treatment of Acquired Undescended Testes: A Review

Acquired undescended testes were once considered a sporadic disease. In recent years, reports suggest that they are not uncommon, with an incidence rate about 3 times that of congenital undescended testes. The etiology of acquired undescended testes remains inconclusive, clinical diagnostic standards are unclear, and treatment approaches are still controversial. There is ongoing debate about the mechanism of testicular ascent. The prevailing view is that acquired undescended testes occur due to the partial absorption of the gubernaculum, which forms part of the parietal peritoneum. The residual gubernacular fibers continuously pull on the spermatic cord, preventing the spermatic cord from elongating proportionately to somatic growth, leading to a re-ascent of the testis. Acquired undescended testes may increase the risk of testicular cancer, but this is still debated. The preferred treatment method is also controversial. However, surgical fixation has an immediate effect; no studies have proven that early surgery improves fertility in patients. The etiology of acquired undescended testes is closely related to the continuous pull of the residual gubernacular fibers on the spermatic cord, which prevents the cord from extending proportionately to body growth. There are no clear diagnostic standards for acquired undescended testes yet, and spontaneous descent is possible, so testicular fixation surgery may not be the preferred treatment method.

Hormone Regulation in Testicular Development and Function

The testes serve as the primary source of androgens and the site of spermatogenesis, with their development and function governed by hormonal actions via endocrine and paracrine pathways. Male fertility hinges on the availability of testosterone, a cornerstone of spermatogenesis, while follicle-stimulating hormone (FSH) signaling is indispensable for the proliferation, differentiation, and proper functioning of Sertoli and germ cells. This review covers the research on how androgens, FSH, and other hormones support processes crucial for male fertility in the testis and reproductive tract. These hormones are regulated by the hypothalamic-pituitary-gonad (HPG) axis, which is either quiescent or activated at different stages of the life course, and the regulation of the axis is crucial for the development and normal function of the male reproductive system. Hormonal imbalances, whether due to genetic predispositions or environmental influences, leading to hypogonadism or hypergonadism, can precipitate reproductive disorders. Investigating the regulatory network and molecular mechanisms involved in testicular development and spermatogenesis is instrumental in developing new therapeutic methods, drugs, and male hormonal contraceptives.

Etiology of Male Infertility: an Update

Spermatogenesis is a complex process of germ cell division and differentiation that involves extensive cross-talk between the developing germ cells and the somatic testicular cells. Defective endocrine signaling and/or intrinsic defects within the testes can adversely affect spermatogenic progression, leading to subfertility/infertility. In recent years, male infertility has been recognized as a global public health concern, and research over the last few decades has elucidated the complex etiology of male infertility. Congenital reproductive abnormalities, genetic mutations, and endocrine/metabolic dysfunction have been demonstrated to be involved in infertility/subfertility in males. Furthermore, acquired factors like exposure to environmental toxicants and lifestyle-related disorders such as illicit use of psychoactive drugs have been shown to adversely affect spermatogenesis. Despite the large body of available scientific literature on the etiology of male infertility, a substantial proportion of infertility cases are idiopathic in nature, with no known cause. The inability to treat such idiopathic cases stems from poor knowledge about the complex regulation of spermatogenesis. Emerging scientific evidence indicates that defective functioning of testicular Sertoli cells (Sc) may be an underlying cause of infertility/subfertility in males. Sc plays an indispensable role in regulating spermatogenesis, and impaired functional maturation of Sc has been shown to affect fertility in animal models as well as humans, suggesting abnormal Sc as a potential underlying cause of reproductive insufficiency/failure in such cases of unexplained infertility. This review summarizes the major causes of infertility/subfertility in males, with an emphasis on infertility due to dysregulated Sc function.

[Hormonal and genetic causes of cryptorchidism]

Cryptorchidism is the most frequent congenital disorders of the reproductive system, is present in 2-3% of term newborn boys. Genes involved in embryonic testicular migration are known but their role in cryptorchidism development are not investigated enough. Genetical causes of cryptorchidism are identified in 5-7% of patients. The article contains data on the role of insulin-like peptide 3 and its receptor, anti-Müllerian hormone, gonadotropins, androgens in embryonic testicular migration. INSL3 and AMH are presented as markers of testicular dysfunction associated with cryptorchidism. Hypogonadotropic hypogonadism is also associated with cryptorchidism and can be diagnosed based on it. Results of modern investigations determine the necessary of hormonal and genetical examination of patients with isolated cryptorchidism to detect causes of cryptorchidism and manage of patients.

Bibliometric analysis of scientific publications on cryptorchidism: Research hotspots and trends between 2000 and 2022

Background

Cryptorchidism is defined as failure of unilateral or bilateral testicular descent, which increases the risk of infertility and testicular carcinoma. Although there is much research on cryptorchidism, few studies have used the bibliometric analysis method. The purpose of this study was to conduct a comprehensive analysis of cryptorchidism from muti-dimensional perspectives to summarize the research hotspots and trends in cryptorchidism research.

Methods

Relevant studies on cryptorchidism were retrieved from the Web of Science Core Collection (WoSCC) database from 2000 to 2022. A comprehensive bibliometric analysis of cryptorchidism was performed by using the CiteSpace, Tableau Public, and VOSviewer software, including the annual distributions of publications, countries, authors, institutions, journals, references, and keywords.

Results

From January 1st, 2000 to May 17th, 2022, a total of 5023 papers concerning cryptorchidism were identified for analysis. The USA contributed the most publications (n = 1193) in this field, and the annual number of publications rose rapidly in China. The University of Melbourne published the largest number of papers (n = 131). "Hutson, John M." was the most core author ranked by publications (n = 51), and "Skakkebaek, Niels E." enjoyed the largest number of citations (4441). The JOURNAL OF UROLOGY published the largest number of papers (n = 225), while the average citations per publication of the 75 papers in HUMAN REPRODUCTION reached 62.38. Additionally, burstness analysis of references and keywords showed that cryptorchidism research was mainly focused on the exploration of the optimal mode of treatment for cryptorchidism, including hypogonadism such as Kallmann syndrome and Klinefelter syndrome.

Conclusion

Cryptorchidism has attracted continuous attention from the scientific community concerned. International collaboration in the field has witnessed significant growth in recent years and remains essential to further enhance collaborative efforts between scholars from different countries. In addition, the exploration of the optimal treatment modality for cryptorchidism, especially in the prevention of adult infertility, remains a major focus of future research. High-quality follow-up studies are also needed in the future. The pathogenesis (especially at the genetic level) and treatment of hypogonadism such as Kallmann syndrome and Klinefelter syndrome have attracted increasing attention recently, which may usher in some breakthroughs in coming years.

Primary culture and endocrine functional analysis of Leydig cells in ducks (Anas platyrhynchos)

Testicular Leydig cells (LCs) are the primary known source of testosterone, which is necessary for maintaining spermatogenesis and male fertility. However, the isolation, identification, and functional analysis of testosterone in duck LCs are still ambiguous. The aim of the present study was to establish a feasible method for isolating highly purified primary duck LCs. The highly purified primary duck LCs were isolated from the fresh testes of 2-month-old ducks via the digestion of collagenase IV and Percoll density gradient centrifugation; hematoxylin and eosin (H&E), immunohistochemistry (IHC) staining, ELISA, and radioimmunoassay were performed. Results revealed that the LCs were prominently noticeable in the testicular interstitium of 2-month-old ducks as compared to 6-month-old and 1-year-old ducks. Furthermore, IHC demonstrated that the cultured LCs occupied 90% area of the petri dish and highly expressed 3β-HSD 24 h after culture (hac) as compared to 48 and 72 hac. Additionally, ELISA and radioimmunoassay indicate that the testosterone level in cellular supernatant was highly expressed in 24 and 48 hac, whereas the testosterone level gradually decreased in 72 and 96 hac, indicating the primary duck LCs secrete testosterone at an early stage. Based on the above results, the present study has effectively developed a technique for isolating highly purified primary duck LCs and identified its biological function in synthesizing testosterone.

Genetic control of typical and atypical sex development

Sex development relies on the sex-specific action of gene networks to differentiate the bipotential gonads of the growing fetus into testis or ovaries, followed by the differentiation of internal and external genitalia depending on the presence or absence of hormones. Differences in sex development (DSD) arise from congenital alterations during any of these processes, and are classified depending on sex chromosomal constitution as sex chromosome DSD, 46,XY DSD or 46,XX DSD. Understanding the genetics and embryology of typical and atypical sex development is essential for diagnosing, treating and managing DSD. Advances have been made in understanding the genetic causes of DSD over the past 10 years, especially for 46,XY DSD. Additional information is required to better understand ovarian and female development and to identify further genetic causes of 46,XX DSD, besides congenital adrenal hyperplasia. Ongoing research is focused on the discovery of further genes related to typical and atypical sex development and, therefore, on improving diagnosis of DSD.

The curious case of testicular descent: factors controlling testicular descent with a note on cryptorchidism

Background

The testicular descent is a uniquely complex process depending upon multiple factors like growth and reorganisation of the specific gonadal ligaments, hormones, etc., which interplay with each other. Though an unambiguous event, it is still laced with incredulity since the data interpretation were intermingled between different species creating more ambiguity in certain aspects of this process. In order to understand the aetiopathology of cryptorchidism the extensive study of the factors controlling the descent is necessitous.

Main body

Though testes originate in the abdomen, they migrate to an extra abdominal site the scrotum, which makes it vulnerable to pathological conditions associated with the descent. The hormones that play vital role in the first phase of descent are insulin-like hormone 3 (INSL3), Anti-müllerian hormone as well as testosterone, whereas androgens, genitofemoral nerve and its neurotransmitter calcitonin gene-related peptide (CGRP) influence the second phase. Despite the vast research regarding the complex nexus of events involving the descent there are disparities among the cross species studies. However all these discrepancies make testicular descent yet again fascinating and perplexing. Our aim is to provide a comprehensive review including recent advances which provides thorough coverage of anatomical and hormonal factors in the descent as well as cryptorchidism.

Conclusion

Though our understanding on testicular descent has evolved over the decades there still has obscurity surrounding it and the studies on the factors responsible for descent are becoming more intense with the time. Our knowledge on many factors such as INSL3 and CGRP is more established now; however, on the other hand the role of androgens still remains speculative. As the knowledge and understanding of the biological process of testicular descent increases it will pave ways to new treatment plans to treat cryptorchidism more effectively.

The RXFP2-PLC/PKC signaling pathway mediates INSL3-induced regulation of the proliferation, migration and apoptosis of mouse gubernacular cells

BACKGROUND

Testicular hypoplasia can affect the sexual and reproductive ability in adulthood, and even increase the risk of cancer. Abnormal development of the gubernaculum is one of the important factors of testicular hypoplasia. Therefore, a study of the structure and function of the gubernaculum is an important but neglected new breakthrough point for investigating the normal/abnormal development of the testis. Previous findings showed that Insulin like factor 3 (INSL3) is a key factor regulating the growth of gubernaculum, however, the mechanism by which INSL3 acts on the gubernaculum remains unknown. Therefore, we probed the mechanism associated with INSL3-induced the proliferation, migration, and apoptosis of gubernacular cells in mice.

METHODS

A culture cell model of neonatal mice gubernaculum is established by INSL3 intervention. We blocked PLC/PKC signaling pathway with U73122 pretreat to investigate the role of the PLC/PKC signaling pathway. The changes of cell proliferation, migration, and apoptosis were detected by molecular biological methods. In addition, the levels of PCNA and F-action were detected by immunofluorescence and western blotting.

RESULTS

We found that INSL3 can promote the proliferation and migration of gubernacular cells and inhibit their apoptosis, meanwhile, INSL3 significantly up-regulated PLC/PKC protein phosphorylation. However, treatment with the PLC/PKC signaling pathway inhibitor U73122 significantly inhibited these effects of INSL3. Besides, we found that INSL3 could up-regulate the protein expression level of PCNA and F-actin, while the PCNA and F-actin expression was significantly weakened after U73122 pretreatment.

CONCLUSIONS

This research revealed that INSL3 binding to RXFP2 may up-regulate the expression levels of PCNA and F-actin by activating the PLC/PKC signaling pathway to promote the proliferation and migration of gubernacular cells. It suggests that the RXFP2-PLC/PKC axis may serve as a novel molecular mechanism by which INSL3 regulates growth of the gubernaculum.

Embryology of the Abdominal Wall and Associated Malformations—A Review

In humans, the incidence of congenital defects of the intraembryonic celom and its associated structures has increased over recent decades. Surgical treatment of abdominal and diaphragmatic malformations resulting in congenital hernia requires deep knowledge of ventral body closure and the separation of the primary body cavities during embryogenesis. The correct development of both structures requires the coordinated and fine-tuned synergy of different anlagen, including a set of molecules governing those processes. They have mainly been investigated in a range of vertebrate species (e.g., mouse, birds, and fish), but studies of embryogenesis in humans are rather rare because samples are seldom available. Therefore, we have to deal with a large body of conflicting data concerning the formation of the abdominal wall and the etiology of diaphragmatic defects. This review summarizes the current state of knowledge and focuses on the histological and molecular events leading to the establishment of the abdominal and thoracic cavities in several vertebrate species. In chronological order, we start with the onset of gastrulation, continue with the establishment of the three-dimensional body shape, and end with the partition of body cavities. We also discuss well-known human etiologies.

Expression and Role of INSL3 in the Fetal Testis

Insulin-like peptide 3 (INSL3) is a small peptide hormone of the insulin-relaxin family which is produced and secreted by the fetal Leydig cells in the testes only. It appears to be undetectable in female fetuses. In the human fetus INSL3 synthesis begins immediately following gonadal sex determination at weeks 7 to 8 post coitum and the peptide can be detected in amniotic fluid 1 to 2 weeks later. INSL3 acts through a unique G-protein-coupled receptor, called RelaXin-like Family Peptide receptor 2 (RXFP2), which is expressed by the mesenchymal cells of the gubernacular ligament linking the testes to the inguinal wall. The role of INSL3 in the male fetus is to cause a thickening of the gubernaculum which then retains the testes in the inguinal region, while the remainder of the abdominal organs grow away in an antero-dorsal direction. This represents the first phase of testis descent and is followed later in pregnancy by the second inguino-scrotal phase whereby the testes pass into the scrotum through the inguinal canal. INSL3 acts as a significant biomarker for Leydig cell differentiation in the fetus and may be reduced by maternal exposure to endocrine disrupting chemicals, such as xenoestrogens or phthalates, leading to cryptorchidism. INSL3 may have other roles within the fetus, but as a Leydig cell biomarker its reduction acts also as a surrogate for anti-androgen action.

BDNF is upregulated by androgen in the inguinal fat pad of immature mice and may regulate inguinoscrotal testicular descent

BACKGROUND

Androgens control rodent inguinoscrotal testicular descent during a "programming window" (E12-17). It is proposed that androgen masculinises the genitofemoral nerve, but the mechanism remains unknown. We investigate androgen receptor (AR)-containing target organs: inguinal fat pad (IFP) and mammary bud (MB), supplied by the genitofemoral nerve, hypothesizing that neurotrophic factors may retrogradely masculinise the GFN.

METHODS

The IFP, MB and bulbocavernosus (BC) muscle were collected at E12.5/E17.5 from androgen receptor knockout (ARKO) mice and wild-type (WT) littermates. Immunofluorescence and gene expression (RT-qPCR; n = 8/group) for Bdnf, active (TrkB) and inactive (truncated TrkB) receptors, Cntf and Cntf receptor were performed.

RESULTS

In the IFP at E12.5, ARKO TrkB mRNA expression was significantly downregulated compared to WT males (p < 0.0026). By E17.5, there was increased Bdnf expression (p < 0.0233). The MB had no differences at E12.5 and had regressed in WT males by E17.5. The BC had no differences at E12.5, but at E17.5 had significant upregulation of Bdnf expression in ARKO, compared to WT males. There were no differences in CNTF or CNTF receptor expression.

CONCLUSIONS

Androgen alters active TrkB and Bdnf expression in the IFP. IFP Bdnf signalling may regulate "masculinisation" of the GFN sensory nerves to indirectly control inguinoscrotal testicular descent.

IMPACT

Androgen mediates neurotrophin release in the inguinal fat pad in mice, which may facilitate normal testicular descent by masculinising the GFN by peripheral uptake of neurotrophin. This is the first study to examine the role of neurotrophins in testicular descent. This suggests novel steps in the mechanical process of normal testicular descent that may be abnormal in some children with undescended testes.

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.

Anti-androgenic compounds in breast milk and cryptorchidism among Norwegian boys in the HUMIS birth cohort

The prevalence of cryptorchidism has increased over the past decades, yet its origins remain poorly understood. Testis descent is dependent on androgens and likely affected by endocrine disrupting compounds (EDCs), targeting the androgen receptor (AR). We investigated the association between anti-androgenic activity, not derived from natural hormones, in maternal breast milk and impaired testis descent among boys. We performed a case-control study based on 199 breast milk samples from 94 mothers of cryptorchid boys and 105 random non-cryptorchid boys participating in the Norwegian HUMIS (Human Milk Study) cohort. For each participant, apolar, and polar fractions were extracted, and combined to reconstitute a mixture. Anti-androgenic activity was measured in all three fractions using the human cell-based in vitro anti-AR CALUX® assay and expressed in μg of flutamide equivalent, a well-known antiandrogen. Results from fraction analyses were compared among boys with cryptorchidism and controls using multiple logistic regression, controlling for appropriate confounders identified using a directed acyclic graph. Children's daily exposure to anti-androgenic EDCs through breastfeeding was estimated to 78 μg flutamide eq./kg of body weigh/day. The activity was higher in the polar fraction (1.48 ± 1.37 μg flutamide eq./g of milk) mainly representing non-persistent chemicals, in contrast to other fractions. However, the activity in the polar extracts was decreased when in mixtures with the apolar fraction, indicating synergistic interactions. No significant difference in the activity was observed according to cryptorchid status for polar, apolar or mixed breast milk fractions. The study showed anti-androgenic activity in nearly all human milk samples, and at levels higher than the advisory threshold. However, no significant association was observed between cryptorchidism and antiandrogenic activity measured in either polar, apolar, or mixture fractions derived from breast milk.

Testicular Tissue Banking for Fertility Preservation in Young Boys: Which Patients Should Be Included?

Due to the growing number of young patients at risk of germ cell loss, there is a need to preserve spermatogonial stem cells for patients who are not able to bank spermatozoa. Worldwide, more and more clinics are implementing testicular tissue (TT) banking programs, making it a novel, yet indispensable, discipline in the field of fertility preservation. Previously, TT cryopreservation was predominantly offered to young cancer patients before starting gonadotoxic chemo- or radiotherapy. Nowadays, most centers also bank TT from patients with non-malignant conditions who need gonadotoxic conditioning therapy prior to hematopoietic stem cell (HSCT) or bone marrow transplantation (BMT). Additionally, some centers include patients who suffer from genetic or developmental disorders associated with prepubertal germ cell loss or patients who already had a previous round of chemo- or radiotherapy. It is important to note that the surgical removal of TT is an invasive procedure. Moreover, TT cryopreservation is still considered experimental as restoration methods are not yet clinically available. For this reason, TT banking should preferably only be offered to patients who are at significant risk of becoming infertile. In our view, TT cryopreservation is recommended for young cancer patients in need of high-risk chemo- and/or radiotherapy, regardless of previous low-risk treatment. Likewise, TT banking is advised for patients with non-malignant disorders such as sickle cell disease, beta-thalassemia, and bone marrow failure, who need high-risk conditioning therapy before HSCT/BMT. TT retrieval during orchidopexy is also proposed for patients with bilateral cryptorchidism. Since patients with a medium- to low-risk treatment generally maintain their fertility, TT banking is not advised for this group. Also for Klinefelter patients, TT banking is not recommended as it does not give better outcomes than a testicular sperm extraction later in life.

Update about the disrupting-effects of phthalates on the human reproductive system

Phthalate esters are synthetic chemicals used in the plastic industry as plasticizers and consumable products. According to United Nations, about 400 million tons of plastic are produced every year. In parallel with increased production, the concerns about its effects on human health have increased because phthalates are endocrine-disrupting compounds. Humans are continuously exposed to phthalates through different routes of exposure. Experimental data have associated the phthalates exposure to adverse effects on development and reproduction in women (e.g., earlier puberty, primary ovarian insufficiency, endometriosis, preterm birth, or in vitro fertilization) and men (e.g., anogenital distance, cryptorchidism, hypospadias, and changes in adult reproductive function) although there is no consensus. Therefore, one question arises: could the increase in infertility be related to phthalates exposure? To answer this question, we aimed to assess the disrupting-effects of phthalates on the human reproductive system. For this, we reviewed the current literature based on epidemiological and experimental data and experimental studies in humans. The phthalate effects were discussed in a separate mode for female and male reproductive systems. In summary, phthalates induce toxicity in the reproductive system and human development. The increased plastic production may be related to the increase in human infertility.

Developmental programming and ageing of male reproductive function

Developmental programming predisposes offspring to metabolic, behavioural and reproductive dysfunction in adult life. Evidence is accumulating that ageing phenotype and longevity are in part developmentally programmed in each individual. Unfortunately, there are few studies addressing the effects of developmental programming by maternal nutrition on the rate of ageing of the male reproductive system. This review will discuss effects of foetal exposure to maternal environmental challenges on male offspring fertility and normal ageing of the male reproductive system. We focus on several key factors involved in reproductive ageing such as decreased hormone production, DNA fragmentation, oxidative stress, telomere shortening, epigenetics, maternal lifestyle and nutrition. There is compelling evidence that ageing of the male reproductive system is developmentally programmed. Both maternal over- or undernutrition accelerate ageing of male offspring reproductive function through similar mechanisms such as decreased serum testosterone levels, increase in oxidative stress biomarkers in both the testes and sperm and changes in sperm quality. Importantly, even in adult life, exercise in male offspring of obese mothers improves adverse effects of programming on reproductive function. Maternal consumption of a low-protein diet causes transgenerational effects in progeny via the paternal line. The seminal fluid has effects on the intrauterine environment. Programming by male factors may involve more than just the sperm. Improving knowledge on developmental programming ageing interactions will improve not only male health and life span but also the health of future generations by reducing programming via the paternal line.

Magnetic Resonance Imagery Findings in Androgen Insensitivity: A case series

Androgen insensitivity syndrome (AIS) is a sex-development disorder resulting from mutations in the androgen receptor. In its complete form, patients are genetically male but phenotypically female, presenting with primary amenorrhea. We report three cases of AIS highlighting the multifaceted role of magnetic resonance imaging (MRI) for presurgical planning by evaluating location and type of gonads and detecting complications. All patients presented at the Gynaecology Out-patient Department of Command Hospital, Bangalore, India, between 2013–2016 with primary amenorrhea and MRI accurately localised testes in all; one patient had bilateral inguinal testes; two had intraabdominal testes. Intraabdominal testes were not localised on ultrasonography. MRI also depicted Sertoli cell adenomas and Wolffian duct remnants. MRI provides comprehensive imaging before surgical treatment and can, thus, be considered a ‘one-stop shop’ for AIS imaging. All patients underwent laparoscopic gonadectomy which is the standard of care, with preoperative counselling about fertility. Postoperatively, they were started on oestrogen therapy.

Development of a putative adverse outcome pathway network for male rat reproductive tract abnormalities with specific considerations for the androgen sensitive window of development

Structured approaches like the adverse outcome pathway (AOP) framework offer great potential for depicting complex toxicological processes in a manner that can facilitate informed integration of mechanistic information in regulatory decisions. While this concept provides a structure for organizing evidence and facilitates consistency in evidence integration; the process, inputs, and manner in which AOPs and AOP networks are developed is still evolving. Following the OECD guiding principles of AOP development, we propose three AOPs for male reproductive tract abnormalities and derive a putative AOP network. The AOPs were developed using a fundamental understanding of the developmental biology of the organs of interest, paying close attention to the gestational timing of key events (KEs) to very specifically inform the domain of life stage applicability for the key event relationships (KERs). Chemical stressor data primarily from studies on low molecular weight phthalates (LMWPs) served to 'bound' the pathways of focus in this dynamic period of development and were integrated with the developmental biology data through an iterative process to define KEs and conclude on the extent of evidence in support of the KERs. The AOPs developed describe the linkage between 1) a decrease in Insl3 gene expression and cryptorchidism, 2) the sustained expression of Coup-tfII and hypospadias and 3) the sustained expression of Coup-tfII and altered Wolffian duct development/ epididymal agenesis. A putative AOP network linking AOP2 and AOP3 through decreased steroidogenic biosynthetic protein expression and converging of all AOPS at the population level impaired fertility adverse outcome is proposed. The network depiction specifies and displays the KEs aligned with their occurrence in gestational time. The pathways and network described herein are intended to catalyze collaborative initiatives for expansion into a larger network to enable effective data collection and inform alternative approaches for identifying stressors impacting this sensitive period of male reproductive tract development.

Posterior urethral valves and the risk of neurodevelopmental disorders in two FINNISH cohorts

BACKGROUND

The Posterior Urethral Valve (PUV) is a persistent membrane of the urethra, which causes obstruction in the urogenital tract in boys. To our knowledge, no comprehensive reports have been published on whether PUV is associated to neurodevelopmental disorders. Here, we analyzed a cohort of PUV patients for neurodevelopmental disorders and verified findings in an older cohort.

METHODS

In a register based study, we reviewed the hospital registries for patients treated for PUV during 1992-2013 to identify those with neurodevelopmental disorders. Primary outcome measure was any neurodevelopmental diagnosis. Secondary outcome measures were specific disorders: ASD; ADHD, intellectual disability, learning disabilities. Birth weight and gestational age were recorded, serum creatinine levels at specific timepoints were noted. We then investigated these variables to see any correlations to neurodevelopmental disorders. We replicated the strategy for verification in an older cohort of PUV-patients, who had been treated in our institute during 1970-1991.

RESULTS

We identified 87 patients treated for PUV of which thirteen (15%) had a verified diagnosis of a neurodevelopmental disorder. 2.3% of PUV patients fulfilled criteria of mild intellectual disability (F70.0/F79.0), 9% had ADHD/ADD-spectrum diagnoses (F90.0/F90.9) and 2.3% had learning disabilities (F83/F81.3). 5.7% of patients presented with difficulties in social interactions (F93.89, F94.8). Five patients presented with more than one neurodevelopmental diagnosis. We confirmed these findings in the older cohort of patients, where a verified neurodevelopmental diagnosis was detected in 14% of patients. We identified no statistically significant associations to gestational age, birth weight or creatinine levels of PUV-patients with neurodevelopmental diagnoses as compared to the PUV-patients not diagnosed for neurodevelopmental disorders. Intellectual disability/mental retardation was more prevalent in our material and this association was statistically significant.

DISCUSSION

We show, that the prevalence of intellectual disability among PUV patients exceeds the cumulative prevalence in Finland in both cohorts analyzed here. 15% of PUV-patients presented with a diagnosis of a neurodevelopmental disorder. To our knowledge, this is the first study attempting to outline neurodevelopmental disorders among boys with PUV. This study has limitations. It is register based and only diagnoses made at an institute within our hospital district are considered. The PUV-patients may be under closer surveillance than age-matched healthy children, which may lead to an overrepresentation of cases. The patient number is small and the small subsets of patients within each cohort hamper any further statistical analysis. The neurodevelopmental impacts of pediatric general anesthesia remain elusive and may have corollaries which must be kept in mind when interpretating our results. Patients with PUV require close follow-up in a multi-disciplinary manner, not forgetting neurodevelopmental aspects. Attention to intellectual disability is mandatory. Any suspicion of a developmental delay in a patient with PUV warrants further investigation and corresponding interventions.

Sonographic evaluation of fetal scrotum, testes and epididymis

External male genitalia have rarely been evaluated on fetal ultrasound. Apart from visualization of the penis for fetal sex determination, there are no specific instructions or recommendations from scientific societies. This study aimed to review the current knowledge about prenatal diagnosis of the scrotum and internal structures, with discussion regarding technical aspects and clinical management. We conducted an article search in Medline, EMBASE, Scopus, Google Scholar, and Web of Science databases for studies in English or Spanish language that discussed prenatal scrotal pathologies. We identified 72 studies that met the inclusion criteria. Relevant data were grouped into sections of embryology, ultrasound, pathology, and prenatal diagnosis. The scrotum and internal structures show a wide range of pathologies, with varying degrees of prevalence and morbidity. Most of the reported cases have described incidental findings diagnosed via striking ultrasound signs. Studies discussing normative data or management are scarce.

Postnatal germ cell development in cryptorchid boys

Cryptorchidism is associated with infertility in adulthood. Early orchiopexy is suggested to reduce the risk. Information is lacking on the potential link between infant germ cell maturation and the risk of future infertility. The objective of the study was to evaluate age-related germ cell development in cryptorchidism. Immunostaining for markers of germ cell development (octamer-binding transcription factor 3/4 [OCT3/4], placental alkaline phosphatase [PLAP], KIT proto-oncogene [C-KIT], podoplanin [D2-40], Lin-28 homolog A [LIN28], and G antigen 7 [GAGE-7]) was performed in testicular biopsies from 40 cryptorchid boys aged 4-35 months. Germ cell numbers and distributions were evaluated in cross sections of seminiferous tubules, with and without immunostaining. OCT3/4, D2-40, and LIN28 were generally expressed in the early stages of germ cell development, as shown by positive expression in germ cells in the central region of seminiferous tubules. In contrast, PLAP and GAGE-7 were expressed in both central and peripheral parts of the tubules in the early stages of development and expressed mainly in a peripheral position with advancing age. Germ cell maturation was delayed in this study population as compared with that observed in our previous study on germ cell markers in a healthy population. The number of GAGE-7-positive germ cells per tubular cross section obtained by immunostaining was significantly higher than that obtained by standard hematoxylin and eosin staining. Double immunostaining revealed heterogeneity in germ cell development in cryptorchid testes. These results shed light on the pathophysiology of germ cell development in boys with cryptorchidism.

The role of intra-abdominal pressure in human testicular migration

Objectives:

This review aims to study the role of the abdominal wall in testicular migration process during the human fetal period.

Materials and Methods:

We performed a descriptive review of the literature about the role of the abdominal wall in testicular migration during the human fetal period.

Results:

The rise in intra-abdominal pressure is a supporting factor for testicular migration. This process has two phases: the abdominal and the inguinal-scrotal stages. The passage of the testis through the inguinal canal occurs very quickly between 21 and 25 WPC. Bilateral cryptorchidism in Prune Belly syndrome is explained by the impaired contraction of the muscles of the abdominal wall; mechanical obstruction due to bladder distention and structural alteration of the inguinal canal, which hampers the passage of the testis during the inguinoscrotal stage of testicular migration. Abdominal wall defects as gastroschisis and omphaloceles are associated with undescended testes in around 30 to 40% of the cases.

Conclusions:

Abdominal pressure wound is an auxiliary force in testicular migration. Patients with abdominal wall defects are associated with undescendend testis in more than 30% of the cases probably due to mechanical factors; the Prune Belly Syndrome has anatomical changes in the anterior abdominal wall that hinder the increase of intra-abdominal pressure which could be the cause of cryptorchidism in this syndrome.

Endocrine disrupting chemicals and reproductive disorders in women, men, and animal models

This chapter covers the known effects of endocrine disrupting chemicals (EDCs) on reproductive disorders. The EDCs represented are highly studied, including plasticizers (bisphenols and phthalates), chemicals in personal care products (parabens), persistent environmental contaminants (polychlorinated biphenyls), and chemicals in pesticides or herbicides. Both female and male reproductive disorders are reviewed in the chapter. Female disorders include infertility/subfertility, irregular reproductive cycles, early menopause, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and uterine fibroids. Male disorders include infertility/subfertility, cryptorchidism, and hypospadias. Findings from both human and animal studies are represented.

Testicular Ectopia in a Child's Anterior Abdominal Wall: A Case Report and Literature Review

Patient: Male, 1.5-year-old

Final Diagnosis: Abdominal wall testicular ectopia

Symptoms: Abdominal swelling • undescended testis

Medication: —

Clinical Procedure: Diagnostic laparoscopy and single stage laparoscopic orchidopexy

Specialty: Pediatrics and Neonatology • Surgery

Epidemiology, Diagnosis and Therapeutic Approaches of Cryptorchidism at the Panzi General Hospital, DR Congo: A 5-year Retrospective Study

Background

Cryptorchidism is a common congenital malformation characterized by unilateral or bilateral undescended testis in the scrotum. It is a common disease in pediatric urology although the prevalence is yet to be determined in the East DR Congo. The aim of this study was to describe the prevalence, clinical and therapeutic features of cryptorchidism at the Panzi General Hospital.

Methods

Medical records of patients who underwent pediatric surgery between January 2011 and December 2016 were reviewed. The prevalence of cryptorchidism, associated malformations, sociodemographic features of patients and therapeutic protocols were examined. Collected data were analyzed using SPSS software.

Results

A total of 5066 children were received during the study period in the service, of which 76 suffered from cryptorchidism giving a prevalence of 1.50% and an annual incidence of 12.70. Unilateral cases were found in 53(69.74%) patients among which 66.04% and 33.96% had unilateral right and left cryptorchidism respectively. Cryptorchidism was associated with other malformations in 71.1% of patients. The age of patients ranged from 0 to 15 years and 78.9% were older than two years. Surgery was the only therapeutic approach and fixation of cryptorchid testis in dartos through inguinal incision was the preferred therapeutic used method.

Conclusion

This study indicates that cryptorchidism is a relatively common and neglected disease in the Est-DR Congo, due to late consultation. Therefore, the local population and pediatricians should be sensitized on scrotal palpation techniques in order to shorten the consultation delay and prevent testis damages.

The role of gonadotrophins in gonocyte transformation during minipuberty

PURPOSE

Postnatal surge of gonadotrophins, Luteinizing hormone (LH) and Follicle-Stimulating hormone (FSH) known as minipuberty, is critical for gonocyte maturation into spermatogonial stem cells (SSC) in the testis. Gonadotrophins are essential for optimum fertility in men, but very little is known how they regulate germ cells during minipuberty. This study examined whether gonadotrophins play a role on gonocyte transformation in vivo.

METHODS

Testes from hypogonadal (hpg) mice and their wild type (WT) littermates (n = 6/group) were weighed, and processed in paraffin at postnatal days (D) 0, 3, 6 and 9. Mouse VASA homologue (germ cell marker), anti-Müllerian hormone (Sertoli cell marker) antibodies and DAPI (nuclei marker) were used for immunofluorescence followed by confocal imaging. Germ cells on or off basement membrane (BM) and Sertoli cells/tubule were counted using Image J and analyzed with GraphPad.

RESULTS

Comparing to WT littermates, there were significantly fewer germ cells on BM/tubule (p < 0.05) in D9 hpg mice, whereas there was no significant difference for germ cells off BM/tubule and Sertoli cells/tubule between littermates. However, testicular weight was significantly reduced in D3-D9 hpg mice comparing to WT littermates.

CONCLUSION

Gonadotrophin deficiency reduced D9 germ cells on BM indicating impaired gonocyte transformation into SSC. This suggests that gonadotrophins may mediate gonocyte transformation during minipuberty.

Structural and functional significance of scrotal ligament: a comparative histological study

Gubernaculum testes is the most important parameter in testicular migration. At the end of migration, it is described as scrotal ligament, which has implications in testicular torsion. The present study aims to examine the structure of scrotal ligament and compare it with gubernaculum. Sixteen adult cadaveric testicular specimens and fourteen fetal testicular specimens of different age groups were examined after getting ethical clearance from the institute ethics committee and consent from the parents. Meticulous dissection was done. The length, site of proximal, and distal attachment of scrotal ligament and gubernaculum were noted and histologically evaluated. A separate scrotal ligament could not be delineated in any adult specimens. It merged with testicular coverings. Histological examination showed the presence of patchy areas of dense collagen fibres of variable density amidst loose areolar connective tissue. In contrast, fetal specimens showed the presence of a definitive gubernaculum testes and revealed the presence of mesenchymal tissue, collagen, elastic fibres, and myocytes which varied according to gestational age of fetuses. Structure of scrotal ligament and gubernaculum testes is highly variable. Description of scrotal ligament as a firm attachment from lower pole of testes to scrotum is controversial, questioning its role as protective factor in testicular torsion.

Interplay between collagenase and undescended testes in Adamts16 knockout rats

BACKGROUND

The inguinoscrotal stage of testicular descent is characterized by an increase in cell density and collagen fibers as the gubernaculum undergoes cell division and increases Extracellular Matrix (ECM) activity. Rats that lack the enzyme Adamts16, a known ECM proteinase, develop cryptorchidism postnatally and are infertile. Therefore, this study aims to investigate the link between the Adamts16 enzyme and congenital undescended testes (UDT) in Adamts16 knockout (KO) rats during postnatal development.

METHODS

Formalin-fixed specimens of Wild-Type, Adamts16 heterozygous and Adamts16 homozygous KO rats post birth were sectioned and used for standard H&E histology and Masson's trichrome staining. A quantitative analysis on image J was performed to determine the intensity of collagen fibers within the inguinoscrotal fat pad (IFP) (n = 3 age/genotype).

RESULTS

The migration of the gubernaculum within the Adamts16 heterozygous and Adamts16 KO rat was considerably disrupted. Furthermore, the Masson's trichrome staining demonstrated a significant increase in collagen fibers around the gubernaculum of rats that lacked Adamts16 enzyme at day 8.

CONCLUSION

This study reports a failure of gubernacular migration leading to UDT in Adamts16 KO rats during development, suggesting that the expression of Adamts16 gene is critical for normal gubernacular migration through the breakdown of collagen fibers within the IFP.

Does the apoptosis pathway play a critical role in gonocyte transformation?

PURPOSE

Undescended Testes (UDT) are prevalent in 2%-5% of male infants and cause malignancy and infertility. During germ cell development, abnormal gonocytes usually undergo apoptosis. This process is believed to involve BAX (Bcl-2 Associated X) protein in clearing abnormal gonocytes which may fail in UDT, resulting in persisting gonocytes causing seminomas later in life. We aim to investigate the role of BAX in gonocyte apoptosis.

MATERIALS AND METHODS

BAXKO (BAX-knockout) mice were back-crossed to OG2 mice (Oct4-promoter driving enhanced green fluorescent protein-eGFP) to produce BAXOG2 mice. Testes (wildtype-BAX^+/+, heterozygous-BAX^+/- and homozygous-BAX^-/- mice, n = 6/group) on postnatal days 1, 3, 6, 9 were fixed and embedded in OCT for frozen sectioning. Sections were labeled with Anti-Müllerian Hormone (Sertoli cell marker), Mouse Vasa Homolog (germ cell marker) and DAPI (nucleus marker) and imaged using confocal microscopy. Oct4-GFP+ve germ cells, germ cells on/off the basement membrane and Sertoli cells were counted using ImageJ followed by data analysis with GraphPad.

RESULTS

BAX^-/-OG2 mice had significantly higher number of germ cells/tubule comparing to BAX^+/+OG2 on day 9. There were Oct4-GFP+ve gonocyte-like germ cells that persisted in the center of the tubules in BAX^-/-OG2 even after the completion of gonocyte transformation. This suggests that abnormal gonocytes in BAX^-/-OG2 mice failed to undergo apoptosis and are allowed to persist.

CONCLUSION

This study demonstrated that apoptosis is important in regulating germ cell migration and differentiation during gonocyte transformation in neonatal mice. In addition, inhibition of apoptosis results in persisting neonatal gonocytes which might become seminomas in patients with UDT.

Male infertility and genitourinary birth defects: there is more than meets the eye

Male factor infertility is a significant problem present in up to 50% of infertile couples. The relationship between male infertility and systemic disease is of significant interest, and emerging evidence suggests a relationship between male infertility and male genitourinary (GU) birth defects (cryptorchidism, hypospadias, ambiguous genitalia, and congenital anomalies of the kidney and urinary tract). Many of these birth defects are treated in isolation by busy urologists without acknowledgment that these may be related to more global syndromic conditions. Conversely, geneticists and nonurologists who treat variable systemic phenotypes may overlook GU defects, which are indeed related conditions. Many of these defects are attributed to copy number variants dosage-sensitive genes due to chromosome microdeletions or microduplications. These variants are responsible for disease phenotypes seen in the general population. The copy number variants described in this review are syndromic in some cases and responsible for both GU birth defects as well as other systemic phenotypes. This review highlights the emerging evidence between these birth defects, male infertility, and other systemic conditions.

Cryptorchidism, gonocyte development, and the risks of germ cell malignancy and infertility: A systematic review

BACKGROUND/AIM

Cryptorchidism, or undescended testis (UDT) occurs in 1%-4% of newborn males and leads to a risk of infertility and testicular malignancy. Recent research suggests that infertility and malignancy in UDT may be caused by abnormal development of the neonatal germ cells, or gonocytes, which normally transform into spermatogonial stem cells (SSC) or undergo apoptosis during minipuberty at 2-6 months in humans (2-6 days in mice). We aimed to identify the current knowledge on how UDT is linked to infertility and malignancy.

METHODS

Here we review the literature from 1995 to the present to assess the possible causes of infertility and malignancy in UDT, from both human studies and animal models.

RESULTS

Both the morphological steps and many of the genes involved in germ cell development are now characterized, but the factors involved in gonocyte transformation and apoptosis in both normal and cryptorchid testes are not fully identified. During minipuberty there is evidence for the hypothalamic-pituitary axis stimulating gonocyte transformation, but without known direct control by LH and androgen, although FSH may have a role. An arrested gonocyte maybe the origin of later malignancy at least in syndromic cryptorchid testes in humans, which is consistent with the recent finding that gonocytes are normally absent in a rodent model of congenital cryptorchidism, where malignancy has not been reported.

CONCLUSION

The results of this review strengthen the view that malignancy and infertility in men with previous UDT may be caused by abnormalities in germ cell development during minipuberty.

TYPE OF STUDY

Systematic review (secondary, filtered) LEVEL OF EVIDENCE: Level I.

Consequences of steroid-5α-reductase deficiency and inhibition in vertebrates

In 1974, a lack of 5α-dihydrotestosterone (5α-DHT), the most potent androgen across species except for fish, was shown to be the origin of a type of pseudohermaphrodism in which boys have female-like external genitalia. This human intersex condition is linked to a mutation in the steroid-5α-reductase type 2 (SRD5α2) gene, which usually produces an important enzyme capable of reducing the Δ⁴-ene of steroid C-19 and C-21 into a 5α-stereoisomer. Seeing the potential of SRD5α2 as a target for androgen synthesis, pharmaceutical companies developed 5α-reductase inhibitors (5ARIs), such as finasteride (FIN) and dutasteride (DUT) to target SRD5α2 in benign prostatic hyperplasia and androgenic alopecia. In addition to human treatment, the development of 5ARIs also enabled further research of SRD5α functions. Therefore, this review details the morphological, physiological, and molecular effects of the lack of SRD5α activity induced by both SRD5α mutations and inhibitor exposures across species. More specifically, data highlights 1) the role of 5α-DHT in the development of male secondary sexual organs in vertebrates and sex determination in non-mammalian vertebrates, 2) the role of SRD5α1 in the synthesis of the neurosteroid allopregnanolone (ALLO) and 5α-androstane-3α,17β-diol (3α-diol), which are involved in anxiety and sexual behavior, respectively, and 3) the role of SRD5α3 in N-glycosylation. This review also features the lesser known functions of SRD5αs in steroid degradation in the uterus during pregnancy and glucocorticoid clearance in the liver. Additionally, the review describes the regulation of SRD5αs by the receptors of androgens, progesterone, estrogen, and thyroid hormones, as well as their differential DNA methylation. Factors known to be involved in their differential methylation are age, inflammation, and mental stimulation. Overall, this review helps shed light on the various essential functions of SRD5αs across species.

RXFP2 as novel potential biomarker for abnormal differentiation induced by diethylstilbestrol in the gubernaculum of fetal mice

Environmental estrogens (EEs) have been correlated with abnormalities in the male urogenital system. However, the mechanism underlying the effect of these molecules remains unclear. In vitro and in vivo experiments were performed to examine the expression level and mechanism of relaxin family peptide receptor 2 (RXFP2) in the gubernaculum of fetal mice following diethylstilbestrol (DES) treatment. The in vivo results demonstrate that DES treatment increased the stillbirth rate gradually, decreased the gubernacular cone volume significantly, and disrupted the tissue structure, leading to incomplete testicular descent. In vitro experiments reveal that DES administration resulted in abnormal cellular morphology and structural disorder of gubernacular cells, which lost their original morphology in a dose-dependent manner. Moreover, DES-induced F-actin rearrangement and stress fiber formation in cultured cells. Protein quantitative analysis showed that the RXFP2 level in each experimental group was significantly lower than that of the normal group. In conclusion, DES affects the morphology and alters the gubernaculum structure, as well as the expression of RXFP2 protein. These data demonstrate that DES is toxic to gubernaculum in fetal mice, and that RXFP2 is associated with the abnormal gubernaculum morphology induced by DES. Taken together, these data suggest that RXFP2 may be a novel potential biomarker for abnormal differentiation of the gubernaculum.

Human chorionic gonadotrophin hormone for treatment of congenital undescended testis: Anatomical barriers to its success

BACKGROUND/PURPOSE

Although the surgical treatment was proved to be the recommended line of management for congenital undescended testis, hormonal therapy with human chorionic gonadotrophin hormone has been started long years ago and is still used in some areas with variable degrees of success. The factors responsible for treatment failure are not well explored. In this study, we aimed to highlight the anatomical abnormalities in the congenital undescended testis that might contribute to treatment failure.

METHODS

During the period from January 2014 to December 2015, 75 boys with congenital undescended testes received treatment with human chorionic gonadotrophin, in pediatric surgery department, Faculty of medicine, Ain Shams University. Their age ranged between 6 months and 4 years (mean 1.6 years, median 2 years). In 70 boys, the testes were palpable and in the remaining 5 boys, the testes were impalpable. Fifty boys had unilateral and 25 had bilateral undescended testes. Seven of the palpable testes were high scrotal in position and the remaining 83 were palpated in the inguinal canal. The patients were followed up for 6 months to determine the position of the testis after the treatment and surgical intervention was done for those who did not respond to the hormonal treatment either partially or completely.

RESULTS

Only 7 testes showed complete descent (7%) (2 bilateral and 3 unilateral) and they were initially high scrotal in position, 8 testes showed partial descent (8%) (2 bilateral and 4 unilateral) and they were inguinal in 6 which became high scrotal and impalpable in 2 which became peeping. The remaining 85 (85%) did not respond to the hormonal treatment. Upon surgical exploration, abnormal attachment of the gubernaculum was found in 83 testes (83%), 2 testes were peeping (2%), short testicular vessels were found in 4 testes (4%), 3 testes were vanishing (3%) and a closed internal ring was found in one testis (1%).

CONCLUSIONS

Treatment of congenital undescended testis with human chorionic gonadotrophin hormone had low success rates. Anatomical abnormalities in the congenital undescended testis might contribute to this treatment failure.

TYPE OF THE STUDY

Clinical research paper.

LEVEL OF EVIDENCE

level III.

Gonocyte transformation in congenital undescended testes: what is the role of inhibin-B in cell death?

PURPOSE

Undescended testes (UDT) are subjected to heat stress, which can disturb gonocyte transformation as well as apoptosis. This study aims to describe the apoptosis pathway occurring during minipuberty of children with unilateral (UDT), and to investigate the role of inhibin-B.

METHODS

Testicular biopsies at unilateral orchidopexy of 10 boys (6-9 months old) with normal inhibin-B (n = 5) or low inhibin-B (n = 5) were selected for immunohistochemistry and TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labelling) assay. Testicular tubules were labelled with antibodies against Anti-Müllerian hormone (AMH, Sertoli cell marker), mouse Vasa Homolog (MVH) and placental alkaline phosphatase (PLAP) (both germ cell markers), cleaved caspase3 (apoptotic marker), and followed by confocal imaging and cell counting with Fiji/ImageJ. Data were analyzed with GraphPad Prism.

RESULTS

In males with low and normal inhibin-B, there was no statistical difference (p > 0.05) in the percentage of testicular tubules containing TUNEL + cells, number of cleaved caspase3 ± germ cells/tubule, total number of germ cells/tubule, and the percentage of fibrotic tubules or number of Sertoli cells/tubule.

CONCLUSIONS

These results suggest that inhibin-B does not regulate cell death of gonocytes and further studies are required to uncover any role of inhibin-B in gonocyte transformation.

Do prune-belly syndrome and neural tube defects change testicular growth? A study on human fetuses

BACKGROUND

There are no reports comparing testicular volume between normal fetuses, fetuses with prune-belly syndrome (PBS), and fetuses with anencephaly. The study hypothesis was that PBS and especially anencephaly alter the testicular volume during the human fetal period.

AIM

The objective of the study was to compare the testicular growth in fetuses with anencephaly, with PBS, and without anomalies.

STUDY DESIGN

This is a morphometric study of human fetuses. Seventy testes from fetuses without anomalies aged 11-22 weeks post-conception (WPC), 30 testes from fetuses with anencephaly aged 13-19 WPC, and eight testes from fetuses with PBS aged 13-16 WPC were studied. Testicular length, width, and thickness were evaluated with the aid of computer programs (Image Pro and ImageJ) (Figure). The fetal testicular volume was calculated using the ellipsoid formula: Testicular volume (TV) = [length × thickness × width] × 0.523. The Shapiro-Wilk test was used to ascertain the normality of the data and to compare quantitative data between normal fetuses vs. fetuses with anencephaly, while the Kruskal-Wallis test was used to assess gender and laterality differences. Simple linear correlations (LCs) were calculated for testicular volume according to fetal age, weight, and crown-rump length.

RESULTS

All 108 testes studied were abdominal. The right (p = 0.0310) and left (0.0470) testicular volumes were significantly smaller in fetuses with anencephaly than those in the control group. The linear regression analysis indicated that the right and the left testis volume in the control group (right: r² = 0.6665; left: r² = 0.6707) and PBS group (right: r² = 0.9937; left: r² = 0.9757) increased with fetal age (p < 0.0001). This analysis also indicated that the testicular volume in fetuses with anencephaly did not increase with fetal age (right: r² = 009816; left: r² = 0.07643).

DISCUSSION

This article is the first to report testicular volume correlations with fetal parameters in fetuses with anencephalic and fetuses with PBS. Significant alterations were observed in testicular growth in the anencephalic group compared with the control group, and it was also observed that the bilateral cryptorchidism in PBS does not alter the testicular development and growth during the fetal period. The unequal WPC distribution between fetuses with PBS, fetuses with anencephaly, and controls and the small sample size are limitations of this study. Further studies should be performed to confirm this study's findings.

CONCLUSIONS

Testicular growth is slower and does not show significant correlations with fetal parameters in fetuses with anencephalic. Significant differences in testicular development in fetuses with PBS was not observed.

Postnatal germ cell development during first 18 months of life in testes from boys with non-syndromic cryptorchidism and complete or partial androgen insensitivity syndrome

INTRODUCTION

Neonatal testicular germ cells/gonocytes, transform into stem cells for spermatogenesis during 'minipuberty', driving change in timing of surgery. This study examined gonocyte transformation in cryptorchid testes in children ≤18 months of age with unilateral, bilateral undescended testes (UDT), complete or partial androgen insensitivity syndrome (CAIS, PAIS) [3,4].

MATERIAL AND METHODS

Testicular biopsies were taken from patients with unilateral or bilateral UDT, PAIS or CAIS, aged 10 days-18 months. These testicular sections underwent immunohistochemistry with antibodies (Oct4, Ki67, C-Kit, Sox9) followed by confocal imaging, cell counting and statistical analysis.

RESULTS

Both Sertoli cells/tubule and germ cells (GC)/tubule decreased with age, and % empty tubules (no GC) increased with age but with no significant differences between patient groups. Oct4⁺ germ cells/tubule decreased with age. There are some GCs and Sertoli cells proliferating during the first year and most proliferating Oct4⁺ germ cells (Oct4⁺/Ki67⁺) were located off tubular basement membrane.

CONCLUSION

Our study showed that Oct4 expression gradually decreased after minipuberty and transformation into spermatogonia. Germ cells and Sertoli cells undergo mitosis during the first 12 months although not abundantly. We propose that Oct4⁺ gonocyte transformation into spermatogonia via proliferation and migration to the basement membrane may be delayed in UDT.

Frequency of inguinal herniotomy in Australia (1998-2017)

BACKGROUND/AIM

Closure of the processus vaginalis (PV) is considered as the last step of testicular descent. Therefore, patent processus vaginalis (PV), and inguinal hernias are linked to cryptorchidism. As the National Australian incidence of orchidopexy has decreased over the previous 20 years, we aimed to explore the incidence of inguinal herniotomy (including hydrocele) over time in Australia.

METHODS

The National Department of Human Services (DHS) database, and Bureau of Statistics database were obtained for the years 1998-2017. The numbers of inguinal herniotomies in patients aged 0-4, 5-14 and 15-24 yearswere examined with ethical approval.

RESULTS

Over the 20-year period, over 87,000 inguinal herniotomy procedures were performed in males. The incidence per year in males decreased across all ages over the 20-year period, but was most pronounced in infants and toddlers. Similar to males, the incidence in females decreased over time, with the ratio of procedures per head of population decreasing in children under 5 years of age. The ratio of male: females varied according to ages, and was between 2.8 and 6.2 males: 1 female.

CONCLUSION

This study suggests that fewer 0-4-year olds are undergoing inguinal herniotomy, compared with 20 years ago. This is likely due to a change in practice for the management of unilateral symptomatic hernias, from routine bilateral herniotomies, to unilateral surgery. As well as less aggressive surgical intervention for hydroceles in boys.

LEVEL OF EVIDENCE

III.

Maternal smoking during pregnancy and risk of cryptorchidism: a systematic review and meta-analysis

The risk factors for undescended testes in male infants and the underlying pathogenesis still remain unclear. The aim of this study is to identify the relationship between maternal smoking during pregnancy and risk of cryptorchidism. A systematic review was conducted using appropriate search terms to identify articles pertaining to maternal smoking during pregnancy and risk of cryptorchidism. Entries up to December 23, 2017 were taken into consideration, without any language or regional restriction. The crude ORs and their 95% CIs were computed by using the fixed-effect model. Twenty studies involving 111,712 infants were included in our meta-analysis. The risk of having a male infant with cryptorchidism was significantly different between mothers who smoked during pregnancy and those who did not (pooled crude OR 1.18, 95% confidence interval [CI] 1.12-1.24, p < 0.00001).Conclusion: Our findings suggest that smoking during pregnancy increased the risk of cryptorchidism by 1.18 times. Further investigations that are well-designed, multicentric studies measuring variables, such as the number of cigarettes smoked in a day and the stage of pregnancy during which the mothers smoked, are necessary to precisely determine the relationship between maternal smoking and risk of cryptorchidism. What is Known: • Preterm and low birth weight have been definitively shown to be risk factors for cryptorchidism. • The relationship between with maternal smoking during pregnancy and risk of cryptorchidism remains controversial all the time. What is New: • Mothers who smoked during pregnancy had a 1.18 times higher risk of having a child with cryptorchidism as compared to those who did not smoke. • Evidence has been found that maternal smoking during pregnancy is a definitive risk factor for cryptorchidism.

Subphenotype meta-analysis of testicular cancer genome-wide association study data suggests a role for RBFOX family genes in cryptorchidism susceptibility

STUDY QUESTION

Can subphenotype analysis of genome-wide association study (GWAS) data from subjects with testicular germ cell tumor (TGCT) provide insight into cryptorchidism (undescended testis, UDT) susceptibility?

SUMMARY ANSWER

Suggestive intragenic GWAS signals common to UDT, TGCT case-case and TGCT case-control analyses occur in genes encoding RBFOX RNA-binding proteins (RBPs) and their neurodevelopmental targets.

WHAT IS KNOWN ALREADY

UDT is a strong risk factor for TGCT, but while genetic risk factors for TGCT are well-known, genetic susceptibility to UDT is poorly understood and appears to be more complex.

STUDY DESIGN, SIZE, DURATION

We performed a secondary subphenotype analysis of existing GWAS data from the Testicular Cancer Consortium (TECAC) and compared these results with our previously published UDT GWAS data, and with data previously acquired from studies of the fetal rat gubernaculum.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Studies from the National Cancer Institute (NCI), United Kingdom (UK) and University of Pennsylvania (Penn) that enrolled white subjects were the source of the TGCT GWAS data. We completed UDT subphenotype case-case (TGCT/UDT vs TGCT/non-UDT) and case-control (TGCT/UDT vs control), collectively referred to as 'TECAC' analyses, followed by a meta-analysis comprising 129 TGCT/UDT cases, 1771 TGCT/non-UDT cases, and 3967 unaffected controls. We reanalyzed our UDT GWAS results comprising 844 cases and 2718 controls by mapping suggestive UDT and TECAC signals (defined as P < 0.001) to genes using Ingenuity Pathway Analysis (IPA®). We compared associated pathways and enriched gene categories common to all analyses after Benjamini-Hochberg multiple testing correction, and analyzed transcript levels and protein expression using qRT-PCR and rat fetal gubernaculum confocal imaging, respectively.

MAIN RESULTS AND THE ROLE OF CHANCE

We found suggestive signals within 19 genes common to all three analyses, including RBFOX1 and RBFOX3, neurodevelopmental paralogs that encode RBPs targeting (U)GCATG-containing transcripts. Ten of the 19 genes participate in neurodevelopment and/or contribute to risk of neurodevelopmental disorders. Experimentally predicted RBFOX gene targets were strongly overrepresented among suggestive intragenic signals for the UDT (117 of 628 (19%), P = 3.5 × 10-24), TECAC case-case (129 of 711 (18%), P = 2.5 × 10-27) and TECAC case-control (117 of 679 (17%), P = 2 × 10-21) analyses, and a majority of the genes common to all three analyses (12 of 19 (63%), P = 3 × 10-9) are predicted RBFOX targets. Rbfox1, Rbfox2 and their encoded proteins are expressed in the rat fetal gubernaculum. Predicted RBFOX targets are also enriched among transcripts differentially regulated in the fetal gubernaculum during normal development (P = 3 × 10-31), in response to in vitro hormonal stimulation (P = 5 × 10-45) and in the cryptorchid LE/orl rat (P = 2 × 10-42).

LARGE SCALE DATA

GWAS data included in this study are available in the database of Genotypes and Phenotypes (dbGaP accession numbers phs000986.v1.p1 and phs001349.v1p1).

LIMITATIONS, REASONS FOR CAUTION

These GWAS data did not reach genome-wide significance for any individual analysis. UDT appears to have a complex etiology that also includes environmental factors, and such complexity may require much larger sample sizes than are currently available. The current methodology may also introduce bias that favors false discovery of larger genes.

WIDER IMPLICATIONS OF THE FINDINGS

Common suggestive intragenic GWAS signals suggest that RBFOX paralogs and other neurodevelopmental genes are potential UDT risk candidates, and potential TGCT susceptibility modifiers. Enrichment of predicted RBFOX targets among differentially expressed transcripts in the fetal gubernaculum additionally suggests a role for this RBP family in regulation of testicular descent. As RBFOX proteins regulate alternative splicing of Calca to generate calcitonin gene-related peptide, a protein linked to development and function of the gubernaculum, additional studies that address the role of these proteins in UDT are warranted.

STUDY FUNDING/COMPETING INTEREST(S)

The Eunice Kennedy Shriver National Institute for Child Health and Human Development (R01HD060769); National Center for Research Resources (P20RR20173), National Institute of General Medical Sciences (P20GM103464), Nemours Biomedical Research, the Testicular Cancer Consortium (U01CA164947), the Intramural Research Program of the NCI, a support services contract HHSN26120130003C with IMS, Inc., the Abramson Cancer Center at Penn, National Cancer Institute (CA114478), the Institute of Cancer Research, UK and the Wellcome Trust Case-Control Consortium (WTCCC) 2. None of the authors reports a conflict of interest.

Gonadotropin-Induced Spermatogenesis in CHH Patients with Cryptorchidism

Congenital hypogonadotropic hypogonadism (CHH) patients with cryptorchidism history usually have poor spermatogenesis outcome, while researches focusing on this population are rare. This study retrospectively evaluated gonadotropin-induced spermatogenesis outcome in CHH patients with cryptorchidism (n = 40). One hundred and eighty-three CHH patients without cryptorchidism were served as control. All patients received combined gonadotropins therapy (HCG and HMG) and were followed up for at least 6 months. The median follow-up period was 24 (15, 33) months (totally 960 person-months). Sperm (>0/ml) initially appeared in semen at a median of estimated 24 months (95% confidence interval (CI) 17.8-30.2). Twenty (20/40, 50%) patients succeeded in producing sperms, and the average time to produce first sperm was 19 ± 8 months. Five pregnancies were achieved in 9 (5/9, 56%) couples who desired for children. Compared with CHH patients without cryptorchidism (n = 183), cryptorchid patients had longer median time for sperm appearance in semen (24 months vs. 15 months, P < 0.001), lower rate of spermatogenesis (50% vs. 67%, P=0.032), and lower mean sperm concentration (1.9 (0.5, 8.6) million/ml vs. 11.1(1.0, 25.0) million/ml, P=0.006) at the last visit. In conclusion, CHH patients with cryptorchidism require a longer period for gonadotropin-induced spermatogenesis. The successful rate and sperm concentration were lower than patients without cryptorchidism.

Postnatal Testicular Activity in Healthy Boys and Boys With Cryptorchidism

Cryptorchidism, or undescended testis, is a well-known risk factor for testicular cancer and impaired semen quality in adulthood, conditions which have their origins in early fetal and postnatal life. In human pregnancy, the interplay of testicular and placental hormones as well as local regulatory factors and control by the hypothalamic-pituitary (HP) axis, lead to testicular descent by term. The normal masculine development may be disrupted by environmental factors or genetic defects and result in undescended testes. Minipuberty refers to the postnatal re-activation of the HP-testicular (T) axis after birth. During the first weeks of life, gonadotropin levels increase, followed by activation and proliferation of testicular Leydig, Sertoli and germ cells. Consequent rise in testosterone levels results in penile growth during the first months of life. Testicular size increases and testicular descent continues until three to five months of age. Insufficient HPT axis activation (e.g., hypogonadotropic hypogonadism) is often associated with undescended testis and therefore minipuberty is considered an important phase in the normal male reproductive development. Minipuberty provides a unique window of opportunity for the early evaluation of HPT axis function during early infancy. For cryptorchid boys, hormonal evaluation during minipuberty may give a hint of the underlying etiology and aid in the evaluation of the later risk of HPT axis dysfunction and impaired fertility. The aim of this review is to summarize the current knowledge of the role of minipuberty in testicular development and descent.

Hypogonadism and Cryptorchidism

Congenital cryptorchidism (undescended testis) is one of the most common congenital urogenital malformations in boys. Prevalence of cryptorchidism at birth among boys born with normal birth weight ranges from 1.8 to 8.4%. Cryptorchidism is associated with a risk of low semen quality and an increased risk of testicular germ cell tumors. Testicular hormones, androgens and insulin-like peptide 3 (INSL3), have an essential role in the process of testicular descent from intra-abdominal position into the scrotum in fetal life. This explains the increased prevalence of cryptorchidism among boys with diseases or syndromes associated with congenitally decreased secretion or action of androgens, such as patients with congenital hypogonadism and partial androgen insensitivity syndrome. There is evidence to support that cryptorchidism is associated with decreased testicular hormone production later in life. It has been shown that cryptorchidism impairs long-term Sertoli cell function, but may also affect Leydig cells. Germ cell loss taking place in the cryptorchid testis is proportional to the duration of the condition, and therefore early orchiopexy to bring the testis into the scrotum is the standard treatment. However, the evidence for benefits of early orchiopexy for testicular endocrine function is controversial. The hormonal treatments using human chorionic gonadotropin (hCG) or gonadotropin-releasing hormone (GnRH) to induce testicular descent have low success rates, and therefore they are not recommended by the current guidelines for management of cryptorchidism. However, more research is needed to assess the effects of hormonal treatments during infancy on future male reproductive health.

Association between androgen receptor polymorphic CAG and GGC repeat lengths and cryptorchidism: A meta-analysis of case-control studies

INTRODUCTION

Previous studies have revealed the relationship between androgen receptor (AR) CAG and/or GGC polymorphisms and risk of cryptorchidism, yet the results have been elusive and controversial.

AIM

To determine whether AR polymorphic CAG and/or GGC repeats are related to cryptorchidism.

STUDY DESIGN

The relevant studies were obtained from PubMed, Embase, China National Knowledge Infrastructure, and Wanfang. The pooled odds ratios with 95% confidence intervals (CIs) were used to assess the strength of associations. Subgroup analyses were performed based on ethnicity and source of controls. Moreover, Begg's funnel plots and Egger's linear regression test were conducted to determine publication bias.

RESULTS

Eight case-control studies containing 321 patients and 784 normal controls were included. There was a significant association between longer CAG repeats and cryptorchidism risk (weighted mean difference (WMD) = 0.62; 95% CIs 0.06, 1.18; P = 0.031). Moreover, there was a significant association between the longer GGC repeats and cryptorchidism risk (WMD = 0.87; 95% CIs 0.04, 1.74; P = 0.040). There was significant association between the longer CAG repeats and bilateral cryptorchidism (WMD = 0.88; 95% CIs -0.18, 1.94; P = 0.011), while there was no significant association between the longer CAG repeats and unilateral cryptorchidism (WMD = -0.09; 95% CIs -0.50, 0.31; P = 0.554). There were significant associations between the longer GGC repeats and unilateral cryptorchidism (WMD = 0.88; 95% CIs -0.30, 2.05; P = 0.005) and bilateral cryptorchidism (WMD = 1.35; 95% CIs -0.52, 3.21; P = 0.000). Stratifying analysis revealed an association between longer CAG/GGC repeats and cryptorchidism in Caucasian populations from Europe (WMD = 0.73; 95% CIs 0.00, 1.46; P = 0.017), while there was no association with Asian populations.

DISCUSSION

This meta-analysis found that CAG/GGC repeats in the AR gene were longer in cryptorchidism patients compared to controls. Both the longer CAG repeats and GGC repeats in the AR gene were associated with cryptorchidism risk. The longer CAG repeats were associated with bilateral cryptorchidism, whereas the longer GGC repeats were associated with unilateral and bilateral cryptorchidism. Stratifying analysis revealed an association between longer CAG/GGC repeats and cryptorchidism in Caucasian populations from Europe, while there was no association between longer CAG/GGC repeats and cryptorchidism in Asian populations.

CONCLUSION

The CAG/GGC repeats in the AR gene were longer in cryptorchidism than in controls. Longer CAG repeats may play a role in determining bilateral cryptorchidism, and longer GGC repeats may play a role in determining unilateral and bilateral cryptorchidism. These observations were more applicable to Caucasian populations.

Amniotic Fluid INSL3 Measured During the Critical Time Window in Human Pregnancy Relates to Cryptorchidism, Hypospadias, and Phthalate Load: A Large Case-Control Study

The period of the first to second trimester transition in human pregnancy represents a sensitive window for fetal organogenesis, particularly in regard to the development of the male reproductive system. This is a time of relative analytical inaccessibility. We have used a large national biobank of amniotic fluid samples collected at routine amniocentesis to determine the impacts of exogenous endocrine disruptor load on specific fetal biomarkers at this critical time. While adrenal and testicular steroids are highly correlated, they are also mostly positively influenced by increasing phthalate load, represented by the metabolites 7cx-MMeHP and 5cx-MEPP, by perfluorooctane sulfonate (PFOS) exposure, and by smoking, suggesting an adrenal stress response. In contrast, the testis specific biomarkers insulin-like peptide 3 (INSL3) and androstenedione are negatively impacted by the phthalate endocrine disruptors. Using a case-control design, we show that cryptorchidism and hypospadias are both significantly associated with increased amniotic concentration of INSL3 during gestational weeks 13-16, and some, though not all steroid biomarkers. Cases are also linked to a specifically increased variance in the Leydig cell biomarker INSL3 compared to controls, an effect exacerbated by maternal smoking. No influence of phthalate metabolites or PFOS was evident on the distribution of cases and controls. Considering that several animal and human studies have shown a negative impact of phthalate load on fetal and cord blood INSL3, respectively, the present results suggest that such endocrine disruptors may rather be altering the relative dynamics of testicular development and consequent hormone production, leading to a desynchronization of tissue organization during fetal development. Being born small for gestational age appears not to impact on the testicular biomarker INSL3 in second trimester amniotic fluid.