Undescended testis: current theories of etiology

Analysis of factors associated with undescended testis in patients with congenital diaphragmatic hernia

PURPOSE

This study aimed to investigate the incidence and clinical factors associated with undescended testes (UDT) in patients with congenital diaphragmatic hernia (CDH).

METHODS

We retrospectively reviewed the incidence of UDT in male neonates admitted to our institution and underwent surgery for CDH between January 2006 and December 2022. Patients were divided into two groups based on the presence or absence of UDT, and risk factors for UDT were compared between the two groups.

RESULTS

Among the 66 male neonates with CDH, 16 (24.2%) developed UDT. Patients with UDT had a significantly smaller gestational age (p = 0.026), lower birth weight (p = 0.042), and lower Apgar score at 1 min (p = 0.016) than those without UDT. They had a significantly higher incidence of large diaphragmatic defects (p = 0.005), received more patch closures (p = 0.020), had a longer mechanical ventilation period (p = 0.034), and longer hospital stay (p = 0.028). Multiple logistic regression analysis revealed that large diaphragmatic defect was an independent risk factor for UDT (adjusted odds ratio of 3.87).

CONCLUSION

CDH and UDT are strongly correlated. In patients with CDH, the incidence of UDT was related not only to patients' prematurity but also to the large diaphragmatic defect. Large diaphragmatic defect is an independent risk factor for UDT in patients with CDH.

Clinical factors related to undescended testis in infants with gastroschisis

BACKGROUND

Recent studies have reported the high incidence of undescended testis (UDT) in patients with gastroschisis. Although various mechanical, hormonal, and genetic theories have been postulated to describe testicular descent, the mechanism contributing to this condition remains controversial. We aimed to investigate the incidence and risk factors of UDT in infants with gastroschisis.

METHODS

Male neonates who underwent surgery for gastroschisis between January 1982 and December 2019 were enrolled. Data were analyzed regarding the prevalence of UDT, including spontaneous testicular descent and the necessity of orchidopexy. Patients were grouped into those with or without UDT to identify the risk factors for UDT.

RESULTS

Among 38 patients with gastroschisis, six (15.8%) developed UDT. There were no significant differences in gestational age or birthweight between patients with and without UDT. The patients with UDT had a significantly larger defect size than those without UDT (P = 0.037). In addition, the timing of abdominal closure was significantly later in patients with UDT than in those without UDT (P = 0.004). None of the patients with UDT exhibited spontaneous testicular descent requiring subsequent orchidopexy.

CONCLUSIONS

Patients with gastroschisis had a high prevalence of UDT. In gastroschisis, the incidence of UDT was related to the defect size and the timing of abdominal wall closure, indicating that an insufficient increase in intra-abdominal pressure during the fetal period may affect the development of UDT.

AKT3 and related molecules as potential biomarkers responsible for cryptorchidism and cryptorchidism-induced azoospermia

BACKGROUND

Cryptorchidism is a common congenital malformation strongly related to future oligospermia and male infertility. Normally functioning early-stage spermatogonia are vital to ensure fertility. The present study aimed to identify new differentially expressed genes (DEGs) associated with signaling pathways related to spermatogonial stem cell (SSC) maintenance during early spermatogenesis.

METHODS

GEO2R was used to screen for genes differentially regulated in cryptorchidism using mRNA expression profiling data in the GEO database. DAVID was used to perform GO and KEGG enrichment analysis of DEGs to analyze their functions. A protein-protein interaction (PPI) network of DEGs was constructed using the STRING database. The hub genes in the PPI networks were identified using Maximal Clique Centrality (MCC) in Cytohubba, and the top 50 genes were displayed as hub genes using Cytoscape software. Then, the miRNAs targeting hub genes were predicted using miRWalk and an mRNA-miRNA interaction network was constructed using Cytoscape. We took the intersection of these target miRNAs and the differentially expressed miRNAs identified from a non-coding RNA sequencing dataset, GSE149084. Furthermore, the intersected miRNAs and their predicted target genes were validated in the testicular tissue of rats with cryptorchidism.

RESULTS

A total of 474 DEGs were identified, most of which were annotated to the PI3K-AKT-mTOR signaling pathway. Hub genes related to the pathway were predicted to be targeted by 27 miRNAs. Further miRNA mining revealed that miRNA-7-5p and miRNA-519d-3p were both dysregulated in cryptorchidism patients. Further, we found that these two miRNAs were predicted with high confidence to share a common target gene, AKT3. In the testicular tissue of rats with cryptorchidism, miRNA-519d-3p was upregulated while miRNA-7-5p and AKT3 were downregulated. We also found that AKT3 plays an essential role in regulating SSC state through the PI3K-AKT-mTOR signaling pathway and that AKT3 is one of the key genes related to SSC self-renewal, proliferation, and differentiation.

CONCLUSIONS

The PI3K-AKT-mTOR signaling pathway functions in SSC maintenance, and alterations in this pathway may explain defects in spermatogenesis. AKT3-related miRNAs, including hsa-miR-7-5p and hsa-miR-519d-3p, might be responsible for cryptorchidism and cryptorchidism-induced azoospermia and serve as potential biomarkers.

Genetics of Equine Reproductive Diseases

Reproductive disorders are genetically heterogeneous and complex; available genetic tests are limited to chromosome analysis and 1 susceptibility gene. Cytogenetic analysis should be the first test to confirm or rule out chromosomal aberrations. No causative genes/mutations are known. The only available genetic test for stallion subfertility is based on a susceptibility gene FKBP6. The ongoing progress in equine genomics will improve the status of genetic testing. However, because subfertile phenotypes do not facilitate collection of large numbers of samples or pedigrees, and clinical causes of many cases remain unknown, further progress requires constructive cross-talk between geneticists, clinicians, breeders, and owners.

Smoking and its association with cryptorchidism in Down syndrome

INTRODUCTION

Cryptorchidism is a common and prevalent condition in patients with Down syndrome. Environmental factors, such as smoking, can be associated with malformations during fetal development. The study of the prevalence of cryptorchidism and its association with parental tobacco use in Down syndrome can contribute to alert health care professionals, patients and family members regarding the prevention of the harms caused by cryptorchidism and its possible predisposing factors.

OBJECTIVE

To evaluate the prevalence of cryptorchidism in Down syndrome and its association with maternal and paternal smoking.

METHOD

Forty (40) patients of a public clinic specialized in Down syndrome were evaluated, using a semi-structured questionnaire for evaluation of antecedents and sociodemographic characteristics, as well as physical and complementary examinations.

RESULTS

Cryptorchidism was observed in 27.5% of the patients (95CI 15.98-42.96). Of these, 55% (5/9) were the children of mothers who smoked during pregnancy, and 19.35% (6/31) were the children of mothers who did not smoke during pregnancy (OR = 5.26 [95CI 1.06-25.41]; p=0.032). Similarly, paternal smoking was also observed in greater frequency among the parents of cryptorchid patients compared with subjects with descended testis, 63.36% (7/11) and 31.03% (9/29), respectively (OR = 3.89 [95CI 0.91-16.73]; p=0.060).

CONCLUSION

The prevalence of cryptorchidism is high in patients with Down syndrome. We can show a strong association between smoking parents and the occurrence of cryptorchidism, especially when it comes to maternal smoking.

Treatment of impalpable testis - one clinic's experience

Introduction

Undescended testes are recognised in 1% to 2% of boys during the first year of life, and about 20% of them are impalpable. Ultrasonography (US) may establish the localisation of the testis but the final diagnosis is usually determined laparoscopically.

Aim

To evaluate long-term results of laparoscopic treatment of boys with impalpable testes and sensitivity of preoperative ultrasound.

Material and methods

Between 2011 and 2015, we operated on 545 boys with undescended testes. Sixty-two of them with 65 impalpable testes were treated laparoscopically – the study group. Mean age was 3.5 years. The study group was divided into 5 groups according to type of treatment. The volume and position of the operated gonad were assessed manually and by ultrasound.

Results

In group 1 testicular agenesis was observed in 19 patients. In group 2 revision of the inguinal canal revealed testicular agenesis in 7 and atrophy in 4 patients. In group 3 conversion to classic orchiopexy was performed in 10 patients. In group 4 one-stage orchiopexy was performed in 9 patients on 12 testes. In group 5 a two-stage F-S procedure was performed in 13 patients. Ten testes in group 4 had a volume in the normal range (84%) and also 10 testes in group 5 (77%).

Conclusions

Laparoscopy in impalpable testes is the procedure of choice and allows definitive management, even when conversion to open procedure is necessary. Sensitivity of preoperative ultrasound is generally about 60% for true intra-abdominal testes, so diagnostic laparoscopy is necessary.

A Case-Control Study of Maternal Polybrominated Diphenyl Ether (PBDE) Exposure and Cryptorchidism in Canadian Populations

BACKGROUND

Polybrominated diphenyl ethers (PBDEs) are flame retardants found in North American household products during the past four decades. These chemicals leach out in dust as products age, exposing individuals daily through inhalation and ingestion. Animal studies suggest that PBDEs disrupt sex hormones and adversely affect development of the reproductive system.

OBJECTIVES

In the present study, we examined whether there is a link between maternal hair PBDE concentrations and the risk of cryptorchidism (undescended testes) in male infants; testis descent is known to be dependent on androgens.

METHODS

Full-term male infants were recruited through clinics in Montreal, Toronto, and London, Canada. Boys with cryptorchidism at 3-18 months of age (n=137) were identified by pediatric urologists and surgeons; similar-aged controls (n=158) had no genitourinary abnormalities as assessed by pediatricians. Eight BDE congeners (BDE-28, -47, -99, -100, -153, -154, -183, -209) were measured by GC-MS (gas chromatography-mass spectrometry) in maternal hair samples collected at the time of recruitment.

RESULTS

The ∑PBDE geometric mean for maternal hair was 45.35 pg/mg for controls and 50.27 pg/mg for cases; the concentrations of three BDEs (BDE-99, -100, and -154) were significantly higher in cases than controls in unadjusted models. In adjusted models, every 10-fold increase in the concentration of maternal hair BDE-99 [OR=2.53 (95% CI: 1.29, 4.95) or BDE-100 [OR=2.45 (95% CI: 1.31, 4.56)] was associated with more than a doubling in the risk of cryptorchidism. BDE-154 [OR=1.88 (95% CI: 1.08, 3.28) was also significant.

CONCLUSIONS

Our results suggest that maternal exposure to BDE-99, -100, and -154 may be associated with abnormal migration of testes in the male fetus. This may be due to the anti-androgenic properties of the PBDEs. https://doi.org/10.1289/EHP522.

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.

Serum Bisphenol A Level in Boys with Cryptorchidism: A Step to Male Infertility?

Cryptorchidism is the most common congenital birth defect in boys and affects about 2-4% full-term male neonates. Its etiology is multifactorial. Purpose. To evaluate the serum bisphenol A (BPA) levels in boys with cryptorchidism and healthy boys and to assess the risk of environmental exposure to BPA using the authors' questionnaire. The data were acquired from a study on boys with cryptorchidism (n = 98) and a control group (n = 57). Prior to surgery, all patients had BPA serum levels evaluated. The size, position, rigidity of the testis, and abnormality of the epididymis of the undescended testis were assessed. Parents also completed a questionnaire on the risks of exposure to BPA in everyday life. Results. The testes in both groups were similar in size. The turgor of the undescended testis in the group of boys with cryptorchidism was decreased. Free serum BPA level in cryptorchid boys and in the control group was not statistically significant (p > 0.05). The conjugated serum BPA level in cryptorchid boys and in the control group was statistically significant (p ≤ 0.05). Total serum BPA level in cryptorchid boys and in the control group was statistically significant (p < 0.05). Serum total BPA level was related with a positive answer about problems with conception (p < 0.02). Conclusion. Our study indicated that high serum BPA was associated with cryptorchidism.

The orl rat is more responsive to methacholine challenge than wild type

BACKGROUND

This study presents an animal model of native airway hyperresponsiveness (AHR). AHR is a fundamental aspect of asthma and reflects an abnormal response characterized by airway narrowing following exposure to a wide variety of non-immunological stimuli. Undescended testis (UDT) is one of the most common male congenital anomalies. The orl rat is a Long Evans substrain with inherited UDT. Since boys born with congenital UDT are more likely to manifest asthma symptoms, the main aim of this study was to investigate the alternative hypothesis that orl rats have greater AHR to a methacholine aerosol challenge than wild type rats.

METHODS

Long Evans wild type (n = 9) and orl (n = 13) rats were anesthetized, tracheostomized, and mechanically ventilated at 4 weeks of age. Escalating concentrations of inhaled methacholine were delivered. The methacholine potency and efficacy in the strains were measured. Respiratory resistance was the primary endpoint. After the final methacholine aerosol challenge, the short-acting β2-adrenoceptor agonist albuterol was administered as an aerosol and lung/diaphragm tissues were assayed for interleukin (IL)-4, IL-6, and tumor necrosis factor (TNF)-α. Histological and histomorphometrical analyses were performed.

RESULTS

The methacholine concentration-response curve in the orl group indicated increased sensitivity, hyperreactivity, and exaggerated maximal response in comparison with the wild type group, indicating that orl rats had abnormally greater AHR responses to methacholine. Histological findings in orl rats showed the presence of eosinophils, unlike wild type rats. β2-Adrenoceptor agonist intervention resulted in up-regulation of IL-4 diaphragmatic levels and down-regulation of IL-4 and IL-6 in the lungs of orl rats.

CONCLUSION

orl rats had greater AHR than wild type rats during methacholine challenge, with higher IL-4 levels in diaphragmatic tissue homogenates. Positive immunostaining for IL-4 was detected in lung and diaphragmatic tissue in both strains. This model offers advantages over other pre-clinical murine models for studying potential mechanistic links between cryptorchidism and asthma. This animal model may be useful for further testing of compounds/therapeutics options for treating AHR.

Does infertility treatment increase male reproductive tract disorder?

OBJECTIVE

To determine the association between assisted human reproduction and male reproductive disorders in infants conceived by this means.

MATERIALS AND METHODS

Between January 2008 and December 2011, 15,332 neonates were born in our hospital. We assessed the birth weight, gestational age, and other characteristics of the 7752 male infants and determined the association between methods of conception and male reproductive disorders in the infants. We also analyzed the influence of male factor on the occurrence of these disorders.

RESULTS

Ninety-nine newborns (1.3%) were diagnosed with cryptorchidism, 8 (0.1%) were diagnosed with hypospadias, and 4 (0.05%) were diagnosed with both. Cryptorchidism was more common in children conceived through in vitro fertilization (IVF) and IVF/intracytoplasmic sperm injection (IVF/ICSI; P <.05), and hypospadias was more common in children conceived through IVF/ICSI (P <.05). Children conceived through intrauterine insemination (IUI), IVF, and IVF/ICSI had higher rates of low birth weight and preterm birth. Logistic regression analysis showed that low birth weight and preterm birth were significantly associated with male reproductive disorders, whereas the method of conception was not. Male factor was not significantly associated with these disorders.

CONCLUSION

IVF and IVF/ICSI increase the risks of low birth weight and preterm birth, resulting in increased rates of hypospadias and cryptorchidism. Male factor was not associated with reproductive disorders in male infants.

Association of placenta organotin concentrations with congenital cryptorchidism and reproductive hormone levels in 280 newborn boys from Denmark and Finland

STUDY QUESTION

Is the placental burden of organotin compounds (OTCs) associated with congenital cryptorchidism in infant offspring from Finland and Denmark?

SUMMARY ANSWER

Increasing concentrations of OTCs had a negative association with cryptorchidism in Finland, whereas a positive association was found in Denmark.

WHAT IS KNOWN ALREADY

The rapid increase in the prevalence of cryptorchidism suggests that environmental factors, such as endocrine disruptors, may be involved. OTCs are endocrine disruptors at very low concentrations due to activation of the retinoid X receptor (RXR).

STUDY DESIGN, SIZE, DURATION

Between the years 1997 and 2001, placentas from mothers of cryptorchid boys and from healthy controls were collected from Denmark (39 cases, 129 controls) and Finland (56 cases, 56 controls). In Denmark 33 and 6 boys, and in Finland 22 and 34 boys had mild or severe cryptorchidism, respectively. The association between concentrations of four OTCs [monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT) and triphenyltin (TPhT)] and case-control status was estimated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In both countries, placenta samples were selected from larger cohorts. In Finland placenta samples were collected from boys with cryptorchidism at birth and matched controls (nested case-control design). Matching criteria were parity, maternal smoking (yes/no), diabetes (yes/no), gestational age (±7 days) and date of birth (±14 days). Numbers of controls per case was 1. In Denmark, all available placentas from cryptorchid boys were chosen and control placentas were selected randomly from the total Danish cohort (case-cohort design). The average number of controls per case was 3.3. OTCs in placenta samples were analysed with liquid extraction, ethylation and gas chromatography-mass spectrometry determination and coded by country-specific tertiles.

MAIN RESULTS AND THE ROLE OF CHANCE

Generally, the concentrations of OTCs were very low. For most analytes, a large proportion of samples (29-96% depending on the country and case-control status) had OTC concentrations below the limit of quantification (LOQ). As an exception, the concentration of TBT was >LOQ in 99% of Finnish placentas. The mean concentrations of DBT and TBT were 1.5 and 7 times higher in Finland than in Denmark, respectively. For DBT in Danish placentas, the odds ratio (OR) for cryptorchidism in the second tertile (0.10-0.14 ng/g) when compared with the first tertile (<0.10 ng/g, <LOQ) was 3.13 (95% CI 1.19-8.26) and the OR for the third tertile (≥0.15 ng/g) when compared with the first tertile was 4.01 (95% CI 1.42-11.33). For TBT in Finnish placentas, the OR for cryptorchidism in the second tertile (0.10-0.39 ng/g) when compared with the first tertile (<0.1 ng/g) was 0.61 (95% CI 0.18-2.01) and the OR for the third tertile (≥0.40 ng/g) when compared with the first tertile was 0.13 (95% CI 0.03-0.54).

LIMITATIONS, REASONS FOR CAUTION

The main limitation of the study was the relatively small number of mother-boy pairs that limits the extrapolation of the study results to the general population. Also misclassification of exposure is a reason for caution for two reasons: because the concentrations of most OTCs were below or only barely above the LOQ in a large proportion of samples and because it is not known how well OTCs measured from placenta represent exposure at the time window that is relevant for cryptorchidism occurrence.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to measure the concentrations of OTCs from human placenta samples, and to associate these concentrations to cryptorchidism. As opposite results were obtained with regard to OTC concentration in placenta and cryptorchidism status in Finland and Denmark, and no mechanism is known at the moment by which OTCs could affect testicular descent, these results cannot be generalized to other populations. However, some animal tests described in the literature show opposite effects of OTCs on fat deposition at different ranges of exposure. It is also clearly shown in the literature that TBT has an impact on sexual development of gastropods through RXR. As TBT is known to activate human RXR, further laboratory studies should be designed to explore the potential impact of TBT on male sexual development.

Pivotal role of the muscle-contraction pathway in cryptorchidism and evidence for genomic connections with cardiomyopathy pathways in RASopathies

BACKGROUND

Cryptorchidism is the most frequent congenital disorder in male children; however the genetic causes of cryptorchidism remain poorly investigated. Comparative integratomics combined with systems biology approach was employed to elucidate genetic factors and molecular pathways underlying testis descent.

METHODS

Literature mining was performed to collect genomic loci associated with cryptorchidism in seven mammalian species. Information regarding the collected candidate genes was stored in MySQL relational database. Genomic view of the loci was presented using Flash GViewer web tool (http://gmod.org/wiki/Flashgviewer/). DAVID Bioinformatics Resources 6.7 was used for pathway enrichment analysis. Cytoscape plug-in PiNGO 1.11 was employed for protein-network-based prediction of novel candidate genes. Relevant protein-protein interactions were confirmed and visualized using the STRING database (version 9.0).

RESULTS

The developed cryptorchidism gene atlas includes 217 candidate loci (genes, regions involved in chromosomal mutations, and copy number variations) identified at the genomic, transcriptomic, and proteomic level. Human orthologs of the collected candidate loci were presented using a genomic map viewer. The cryptorchidism gene atlas is freely available online: http://www.integratomics-time.com/cryptorchidism/. Pathway analysis suggested the presence of twelve enriched pathways associated with the list of 179 literature-derived candidate genes. Additionally, a list of 43 network-predicted novel candidate genes was significantly associated with four enriched pathways. Joint pathway analysis of the collected and predicted candidate genes revealed the pivotal importance of the muscle-contraction pathway in cryptorchidism and evidence for genomic associations with cardiomyopathy pathways in RASopathies.

CONCLUSIONS

The developed gene atlas represents an important resource for the scientific community researching genetics of cryptorchidism. The collected data will further facilitate development of novel genetic markers and could be of interest for functional studies in animals and human. The proposed network-based systems biology approach elucidates molecular mechanisms underlying co-presence of cryptorchidism and cardiomyopathy in RASopathies. Such approach could also aid in molecular explanation of co-presence of diverse and apparently unrelated clinical manifestations in other syndromes.

The controversy regarding the need for hormonal treatment in boys with unilateral cryptorchidism goes on: a review of the literature

Hormonal treatment for unilateral undescended testes continues to be recommended in some countries. We reviewed the literature in favor and against this recommendation. Since the paternity rate of men with a history of unilateral undescended testes only treated with surgery is normal, the effectiveness of hormonal treatment to produce testicular descent is low, the cost is considerable, and there are potential adverse effects, hormonal treatment for boys with unilateral undescended testes should no longer be recommended.

Transumbilical multiport laparoscopic orchiopexy in children: comparison with standard laparoscopic orchiopexy

OBJECTIVE

To compare the clinical outcomes of transumbilical multiport laparoscopic orchiopexy (TMLO) vs standard laparoscopic orchiopexy (SLO) for 1-stage management of impalpable testes in children.

MATERIALS AND METHODS

A total of 30 patients underwent primary TMLO from January 2010 to December 2011. An additional 25 patients underwent SLO during the same period. These 2 procedures were performed with 3 ports and the usual laparoscopic instruments. The demographic, intraoperative, postoperative, and follow-up data were analyzed and compared between the patients.

RESULTS

The patients' demographic data were similar between the 2 groups. The mean operative time was slightly longer in the TMLO than in the SLO group (54.2 vs 47.3 minutes, P <.05), without intraoperative complications in either group. However, no significant difference was noted between the TMLO and SLO groups in the length of hospital stay (4.0 vs 4.1 days, P >.05), interval to resume feeding (5.2 vs 5.4 hours, P >.05) or full activity (2.1 vs 2.2 days, P >.05), viable testis rate (33 of 34 vs 27 of 28, P >.05), or testicular atrophy (1 of 34 vs 1 of 28, P >.05).

CONCLUSION

TMLO is a feasible and safe procedure for the management of impalpable testes in children, with clinical outcomes similar to those of SLO. Future randomized studies with a larger number of patients and longer follow-up are warranted to elucidate the benefits and limitations of TMLO in children.

[Cryptorchidism associated with ectopic adrenal cortical tissue in the spermatic cord in a 51-year-old male]

This case report describes an exceptional case of ectopic adrenal cortex tissue (EACT) in the spermatic cord associated with ipsilateral cryptorchidism in an adult. While both EACT and cryptorchidism are fairly common congenital anomalies in boys, adult cases are uncommon. Although the spermatic cord is a known site of EACT, the reports of its association with cryptorchidism have been limited to child cases. During surgery, undescended testis was discovered and incidentally ectopic adrenal tissue along the spermatic cord was also identified. This combination of developmental aberrations in the adult has not been described, and the clinicopathological findings are reported with a brief literature review.

Reduced expression of androgen receptor and myosin heavy chain mRNA in cremaster muscle of boys with nonsyndromic cryptorchidism

PURPOSE

To better define the developmental mechanisms of nonsyndromic cryptorchidism, we measured the expression of hormone receptor and muscle type specific mRNAs in target tissues of boys with and those without nonsyndromic cryptorchidism.

MATERIALS AND METHODS

Prospectively collected cremaster muscle and/or hernia sac tissues from boys with congenital (79) or acquired (66) nonsyndromic cryptorchidism and hernia/hydrocele (controls, 84) were analyzed for hormone receptor (RXFP2, AR, ESR1, ESR2) and myosin heavy chain specific (MYH1, MYH2, MYH7) mRNA expression using real-time reverse transcriptase polymerase chain reaction. Log transformed mRNA, phenotype and feeding history data were statistically analyzed using Pearson's correlation, ANOVA and 2-sample t tests.

RESULTS

AR mRNA expression was higher in cremaster muscle than in sac tissue, and significantly lower in congenital and acquired nonsyndromic cryptorchidism cases vs controls (p <0.01). Type 1 (slow/cardiac) MYH7 mRNA expression was also significantly reduced in both nonsyndromic cryptorchidism groups (p ≤ 0.002), while a reduction in type 2 (fast) MYH2 expression was more modest and significant only for the congenital cryptorchidism group (p <0.05). Cremasteric MYH7 and AR levels were strongly correlated (r(2) = 0.751, p <0.001). MYH7 and ESR1 mRNA levels were higher and lower, respectively, in boys with nonsyndromic cryptorchidism who were fed soy formula. Expression of other genes was not measurable.

CONCLUSIONS

Our data suggest that boys with congenital and acquired nonsyndromic cryptorchidism differentially express AR and slow twitch specific MYH7 mRNA in the cremaster muscle, and that MYH7 expression is correlated with AR levels and soy formula use. These differences in gene expression may reflect aberrant hormonal signaling and/or innervation during development with the potential for secondary functional effects and failed testicular descent.

Environmental and genetic contributors to hypospadias: a review of the epidemiologic evidence

This review evaluates current knowledge related to trends in the prevalence of hypospadias, the association of hypospadias with endocrine-disrupting exposures, and the potential contribution of genetic susceptibility to its etiology. The review focuses on epidemiologic evidence. Increasing prevalence of hypospadias has been observed, but such increases tend to be localized to specific regions or time periods. Thus, generalized statements that hypospadias is increasing are unsupported. Owing to the limitations of study designs and inconsistent results, firm conclusions cannot be made regarding the association of endocrine-disrupting exposures with hypospadias. Studies with more rigorous study designs (e.g., larger and more detailed phenotypes) and exposure assessment that encompasses more breadth and depth (e.g., specific endocrine-related chemicals) will be critical to make better inferences about these important environmental exposures. Many candidate genes for hypospadias have been identified, but few of them have been examined to an extent that enables solid conclusions. Further study is needed that includes larger sample sizes, comparison groups that are more representative of the populations from which the cases were derived, phenotype-specific analyses, and more extensive exploration of variants. In conclusion, examining the associations of environmental and genetic factors with hypospadias remain important areas of inquiry, although our actual understanding of their contribution to hypospadias risk in humans is currently limited.

Male reprotoxicity and endocrine disruption

Mammalian reproductive tract development is a tightly regulated process that can be disrupted following exposure to drugs, toxicants, endocrine-disrupting chemicals (EDCs), or other compounds via alterations to gene and protein expression or epigenetic regulation. Indeed, the impacts of developmental exposure to certain toxicants may not be fully realized until puberty or adulthood when the reproductive tract becomes sexually mature and altered functionality is manifested. Exposures that occur later in life, once development is complete, can also disrupt the intricate hormonal and paracrine interactions responsible for adult functions, such as spermatogenesis. In this chapter, the biology and toxicology of the male reproductive tract is explored, proceeding through the various life stages including in utero development, puberty, adulthood, and senescence. Special attention is given to the discussion of EDCs, chemical mixtures, low-dose effects, transgenerational effects, and potential exposure-related causes of male reproductive tract cancers.

Laparoscopic management of impalpable testes: comparison of different techniques

PURPOSE

Laparoscopy is an important modality for management of impalpable testes. We present long-term outcomes of intra-abdominal testes managed by either single stage orchidopexy or two-stage Fowler Stephen's orchidopexy (FSO) over 12 years.

METHODS

Data were prospectively collected and retrospectively analyzed on patients who underwent laparoscopy for impalpable testes between 1998 and 2010. Demographic data, intra-operative findings, management, histology and follow-up findings were collected and analyzed. Fisher's Exact test was used for statistical analysis.

RESULTS

Laparoscopy was performed for 168 impalpable testes (78 left, 58 right and 16 bilateral). Patients were between 8 months and 15 years of age (median 1 year 10 months). Ninety-three testes were found to have cord structures entering the inguinal ring (canalicular), 65 were intra-abdominal and 10 had blind ending vas and/or vessel. Fifty-seven (34%) testes were atrophic and underwent orchidectomy; 100 (60%) testes underwent orchidopexy: either two-stage FSO (48) or single stage orchidopexy (52) and 10 (7%) had findings consistent with 'vanishing testes'. Histopathologically, the excised remnants (34%) showed no viable testicular tissue. The follow-up was a median of 8 months (3 months to 6 years). Four patients were lost to follow-up (two each after FSO and single stage orchidopexy) while, two FSO are awaiting follow-up. At follow-up, 36/44 testes (FSO) and 13/13 testes (single stage orchidopexy) are in the scrotum and of good size. Eight testes had atrophied after two-staged FSO.

CONCLUSION

Canalicular testes are often difficult to palpate (55%). Laparoscopy allows direct visualization and definitive management. There is no statistically significant difference between the results following single stage orchidopexy or two-stage FSO for impalpable testes.

The risk of cryptorchidism among sons of women working in horticulture in Denmark: a cohort study

BACKGROUND

Androgens are crucial for normal testicular descent. Studies show that some pesticides have estrogenic or antiandrogenic effects, and that female workers exposed to pesticides have increased risk of having a boy with cryptorchidism. The main objective of the present study was to investigate whether pregnant women exposed to pesticides due to their work in horticulture experience excess risk of having sons with cryptorchidism.

METHODS

We conducted a cohort study of pregnant women working in horticulture using four cohorts including one cohort established with data from the departments of occupational medicine in Jutland and Funen and three existing mother-child cohorts (n=1,468). A reference group was established from the entire Danish population of boys born in the period of 1986-2007 (n=783,817). Nationwide Danish health registers provided information on birth outcome, cryptorchidism diagnosis and orchiopexy. The level of occupational exposure to pesticides was assessed by expert judgment blinded towards outcome status. Risk of cryptorchidism among exposed horticulture workers compared to the background population and to unexposed horticulture workers was assessed by Cox regression models.

RESULTS

Pesticide exposed women employed in horticulture had a hazard ratio (HR) of having cryptorchid sons of 1.39 (95% CI 0.84; 2.31) and a HR of orchiopexy of 1.34 (0.72; 2.49) compared to the background population. Analysis divided into separate cohorts revealed a significantly increased risk of cryptorchidism in cohort 2: HR 2.58 (1.07;6.20) and increased risk of orchiopexy in cohort 4: HR 2.76 (1.03;7.35), but no significant associations in the other cohorts. Compared to unexposed women working in horticulture, pesticide exposed women had a risk of having sons with cryptorchidism of 1.34 (0.30; 5.96) and of orchiopexy of 1.93 (0.24;15.4).

CONCLUSIONS

The data are compatible with a slightly increased risk of cryptorchidism in sons of women exposed to pesticides by working in horticulture.

Management of cryptorchidism and gastroschisis

BACKGROUND

Cryptorchidism is commonly associated with gastroschisis. Management of the undescended testes varies with regard to technique and timing of orchidopexy. To evaluate the appropriate timing of and procedure for orchidopexy in patients with gastroschisis, we reviewed our experience.

METHODS

Male neonates admitted between January 1999 and September 2010 with gastroschisis were reviewed. This retrospective study was conducted after institutional review board approval. Testis location at birth was recorded, and outcomes for those with undescended testes were analyzed.

RESULTS

Sixty-two males with gastroschisis were identified, and 24 had cryptorchidism (38.7%) affecting 31 testes. All babies had an initial watch-and-wait approach without any attempt at orchidopexy during gastroschisis closure. Those with extraabdominal testes at birth had the testicle repositioned in the abdomen before gastroschisis closure. Mean follow-up was 27.3 months. At follow-up, 54.8% of the testes relocated without intervention and 38.7% required orchidopexy. Laparoscopy was used in 5 patients to perform the orchidopexy. A total of 3 testes required orchiectomy secondary to atrophy, one of which had previously undergone an orchidopexy. Two of the orchiectomies were performed laparoscopically.

CONCLUSION

The watch-and-wait approach for cryptorchidism in gastroschisis is safe and appropriate, with a high rate of spontaneous migration during the first year of life and greater than 90% testes viable at follow-up. Laparoscopy is a safe and feasible option for management of undescended testes that remain intraabdominal at follow-up.

Cryptorchidism and hypospadias as a sign of testicular dysgenesis syndrome (TDS): environmental connection

Cryptorchidism and hypospadias are common genital birth defects that affect 2-9% and 0.2-1% of male newborns, respectively. The incidence of both defects shows large geographic variation, and in several countries increasing trends have been reported. The conditions share many risk factors, and they are also interlinked to the risk of testis cancer and poor semen quality. Testicular Dysgenesis Syndrome (TDS) may underlie many cases of all these male reproductive health problems. Genetic defects in androgen production or action can cause both cryptorchidism and hypospadias, but these are not common. A monogenic reason for cryptorchidism or hypospadias has been identified only in a small proportion of all cases. Environmental effects appear to play a major role in TDS. Exposure to several persistent chemicals has been found to be associated with the risk of cryptorchidism, and exposure to anti-androgenic phthalates has been shown to be associated with hormonal changes predisposing to male reproductive problems. Despite progress in identification of endocrine-disrupting substances, we are still far from knowing all the risk factors for these birth defects, and advice for prevention must be based on precautionary principles.

Perioperative surgical findings in congenital and acquired undescended testis

PURPOSE

Perioperative surgical findings in congenital and acquired undescended testis (UDT) were prospectively assessed.

METHODS

We included all boys with congenital or acquired UDT who underwent orchidopexy at our hospital between January 2006 and August 2009. Perioperatively, we scored the position and volume of the testis, the insertion of the gubernaculum, the patency of the processus vaginalis, and the obtained position.

RESULTS

We included 69 boys (aged 0.9-14.6 years) with 76 congenital UDT and 28 boys (aged 2.2-18.5 years) with 30 acquired UDT. In the congenital group, the testis was in intracanalicular position in 55 cases (72%), whereas in the acquired UDT group, this was in 11 cases (37%; P < .001). The insertion of the gubernaculum was at the bottom of the scrotum in 13 cases (17%) of the congenital UDT group and in 12 cases (40%) of the acquired UDT group (P < .05). The processus vaginalis was open in 63 cases (83%) of the congenital and in 9 cases (30%) of the acquired UDT group (P < .001).

CONCLUSION

Compared to congenital UDT, acquired UDT are more likely to be situated in the superficial inguinal pouch, to have a normal insertion of the gubernaculums, and to have a closed processus vaginalis.

Insulin-like 3 exposure of the fetal rat gubernaculum modulates expression of genes involved in neural pathways

Insulin-like 3 (INSL3) signaling directs fetal gubernacular development and testis descent, but the actions of INSL3 in the gubernaculum are poorly understood. Using microarray gene expression profiling of fetal male rat gubernaculum explants exposed to 10 or 100 nM INSL3, significant changes in expression were identified for approximately 900 genes. Several of the genes showing the largest inductions regulate neuronal development or activity, including Pnoc (34-fold), Nptx2 (9-fold), Nfasc (4-fold), Gfra3 (3-fold), Unc5d (3-fold), and Crlf1 (3-fold). Bioinformatics analysis revealed BMP and WNT signaling pathways and several gene ontologies related to neurogenesis were altered by INSL3. Promoter response elements significantly enriched in the INSL3-regulated gene list included consensus sequences for MYB, REL, ATF2, and TEF transcription factors. Comparing in vivo gene expression profiles of male and female rat fetal gubernaculum showed expression of the Bmp, Wnt, and neurodevelopmental genes induced by INSL3 was higher in males. Using quantitative RT-PCR, the microarray data were confirmed, and the induction of Bmp3, Chrdl2, Crlf1, Nptx2, Pnoc, Wnt4, and Wnt5a mRNA levels were examined over a range of INSL3 concentrations (0.1-100 nM) in male and female gubernaculum. In both sexes, an increasing gene expression response was observed between 0.1 and 10 nM INSL3. These data suggest that INSL3 signaling in the fetal gubernaculum induces morphogenetic programs, including BMP and WNT signaling, and support other rodent data suggesting a role for these pathways in development of the gubernaculum.

Laparoscopic orchidopexy: the easy way to go

BACKGROUND/PURPOSE

Intraabdominal testes represent less than 10% of cryptorchid testicles, and yet, they are the most challenging to correct. In the last 15 years, the two-stage Fowler-Stephens orchidopexy has gained popularity. The traditional approach includes laparoscopic or open clipping of the testicular vessels (first stage) and open inguinal orchidopexy (second stage). We present our experience with 2-stage orchidopexy with both stages done through a laparoscopic approach.

MATERIALS AND METHODS

Over a recent 5-year period, we reviewed patients operated for intraabdominal testis using a two-stage laparoscopic orchidopexy with a minimum of 1-year follow-up. In this study, success is defined as a nonatrophic, intrascrotal testis. Fifteen patients met the inclusion criteria, and none were lost to follow-up.

RESULTS

In the 15 patients, 11 had a unilateral intraabdominal testis, and 4 had bilateral cryptorchidism, with one of the 2 testes intraabdominal. The first stage was done at a mean age of 32 months, and the average time between the two stages was 9.7 months. All procedures (31) were done on an outpatient basis. Only 2 complications occurred, one scrotal hematoma and one redo first stage because of unsuccessful clipping noted at the time of planned second stage. The success rate is 93.3% (14/15). All testicles are intrascrotal, and all but 1 have maintained preoperative volume.

CONCLUSION

Two-stage laparoscopic orchidopexy is a fairly easy surgical procedure with minimum morbidity and high short term success rate. A larger cohort of patients with long-term follow-up is needed to substantiate these findings.

Maternal pregnancy levels of polychlorinated biphenyls and risk of hypospadias and cryptorchidism in male offspring

BACKGROUND

The etiologies of the male urogenital anomalies cryptorchidism and hypospadias are poorly understood. It has been suggested, however, that in utero hormone levels may be related to risk. Endocrine-disrupting chemicals, including polychlorinated biphenyl (PCB) compounds, may alter hormone levels and thereby affect the fetus.

OBJECTIVES

To examine whether in utero PCB exposure is related to cryptorchidism and hypospadias, we examined PCB levels among pregnant women enrolled in the Collaborative Perinatal Project (CPP).

METHODS

The CPP enrolled pregnant women at 12 U.S. medical centers between 1959 and 1965. For the present research, we analyzed third-trimester serum samples from the mothers of 230 sons with cryptorchidism, 201 sons with hypospadias, and 593 sons with neither condition. We estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression and examined the associations of each anomaly with individual PCB congener levels, sum of PCBs, and several functional groupings of PCBs.

RESULTS

In general, the ORs for cryptorchidism or hypospadias showed no notable associations with individual PCB congener levels or functional groupings of PCBs. However, the ORs and 95% CIs for the sum of PCBs associated with hypospadias were as follows: 0-1.9 microg/L, reference group; 2-2.9 microg/L, OR = 1.57, 95% CI, 1.05-2.34; 3-3.9 microg/L, OR = 1.45, 95% CI, 0.90-2.34; and > or = 4.0 microg/L, OR = 1.69, 95% CI, 1.06-2.68; p-value for trend = 0.08.

CONCLUSIONS

Given the large number of associations examined, these findings do not strongly support the hypothesis that PCBs are associated with cryptorchidism or hypospadias. Because population serum PCB levels at the time of sample collection were considerably higher than levels at present, it is unlikely that current PCB exposure is related to the development of either anomaly.