Prenatal ethanol exposure delays the onset of spermatogenesis in the rat

BACKGROUND

During late prenatal and early postnatal life, the reproductive system in males undergoes an extensive series of physiological and morphological changes. Prenatal ethanol (EtOH) exposure has marked effects on the development of the reproductive system, with long-term effects on function in adulthood. The present study tested the hypothesis that prenatal EtOH exposure will delay the onset of spermatogenesis.

METHODS

Development of the seminiferous tubules and the onset of spermatogenesis were examined utilizing a rat model of fetal alcohol spectrum disorder (FASD). Male offspring from ad libitum-fed control (C), pair-fed (PF), and EtOH-fed (prenatal alcohol exposure [PAE]) dams were terminated on postnatal (PN) days 5, 15, 18, 20, 25, 35, 45, and 55, to investigate morphological changes through morphometric analysis of the testes from early neonatal life through young adulthood.

RESULTS

PAE males had lower relative (adjusted for body weight) testis weights compared with PF and/or C males from PN15 through puberty (PN45). In addition, fewer gonocytes (primordial germ cells) were located on the basal lamina on PN5, while more of those touching the basal lamina were dividing in PAE compared with PF and C males, suggesting delayed cell division and migration processes. As well, the percentage of tubules with open lumena was lower in PAE compared with PF and C males on PN18 and 20, and PAE males had fewer primary spermatocytes per tubule on PN18 and round spermatids per tubule on PN25 compared with C males. Finally, the percentage of tubules at stages VII and VIII, when mature spermatids move to the apex of the epithelium and are released, was lower in PAE compared with PF and/or C males in young adulthood (PN55).

CONCLUSIONS

Maternal EtOH consumption appears to delay both reproductive development and the onset of spermatogenesis in male offspring, with effects persisting at least until young adulthood.

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.

Anti-müllerian hormone: a valuable addition to the toolbox of the pediatric endocrinologist

Anti-Müllerian hormone (AMH), secreted by immature Sertoli cells, provokes the regression of male fetal Müllerian ducts. FSH stimulates AMH production; during puberty, AMH is downregulated by intratesticular testosterone and meiotic germ cells. In boys, AMH determination is useful in the clinical setting. Serum AMH, which is low in infants with congenital central hypogonadism, increases with FSH treatment. AMH is also low in patients with primary hypogonadism, for instance in Down syndrome, from early postnatal life and in Klinefelter syndrome from midpuberty. In boys with nonpalpable gonads, AMH determination, without the need for a stimulation test, is useful to distinguish between bilaterally abdominal gonads and anorchism. In patients with disorders of sex development (DSD), serum AMH determination helps as a first line test to orientate the etiologic diagnosis: low AMH is indicative of dysgenetic DSD whereas normal AMH is suggestive of androgen synthesis or action defects. Finally, in patients with persistent Müllerian duct syndrome (PMDS), undetectable serum AMH drives the genetic search to mutations in the AMH gene, whereas normal or high AMH is indicative of an end organ defect due to AMH receptor gene defects.

Human infertility: are endocrine disruptors to blame?

Over recent decades, epidemiological studies have been reporting worrisome trends in the incidence of human infertility rates. Extensive detection of industrial chemicals in human serum, seminal plasma and follicular fluid has led the scientific community to hypothesise that these compounds may disrupt hormonal homoeostasis, leading to a vast array of physiological impairments. Numerous synthetic and natural substances have endocrine-disruptive effects, acting through several mechanisms. The main route of exposure to these chemicals is the ingestion of contaminated food and water. They may disturb intrauterine development, resulting in irreversible effects and may also induce transgenerational effects. This review aims to summarise the major scientific developments on the topic of human infertility associated with exposure to endocrine disruptors (EDs), integrating epidemiological and experimental evidence. Current data suggest that environmental levels of EDs may affect the development and functioning of the reproductive system in both sexes, particularly in foetuses, causing developmental and reproductive disorders, including infertility. EDs may be blamed for the rising incidence of human reproductive disorders. This constitutes a serious public health issue that should not be overlooked. The exposure of pregnant women and infants to EDs is of great concern. Therefore, precautionary avoidance of exposure to EDs is a prudent attitude in order to protect humans and wildlife from permanent harmful effects on fertility.

Boys with undescended testes: endocrine, volumetric and morphometric studies on testicular function before and after orchidopexy at nine months or three years of age

CONTEXT

A randomized controlled study was conducted comparing the outcome of surgery for congenital cryptorchidism at 9 months or 3 yr of age.

OBJECTIVE

The aim of the study was to investigate whether surgery at 9 months is more beneficial than at 3 yr and to identify early endocrine markers of importance for testicular development.

PATIENTS AND METHODS

A total of 213 biopsies were taken at orchidopexy, and the number of germ and Sertoli cells per 100 seminiferous cord cross-sections and the surface area of seminiferous tubules and interstitial tissue were analyzed. Inhibin B, FSH, LH, and testosterone were determined. Testicular volume was assessed by ultrasonography and by a ruler.

RESULTS

The number of germ and Sertoli cells and testicular volume at 9 months were significantly larger than at 3 yr. The intraabdominal testes showed the largest germ cell depletion at 3 yr. At both ages, testicular volume correlated to the number of germ and Sertoli cells. None of the hormones measured during the first 6 months of life (LH, FSH, testosterone, and inhibin B) could predict the number of germ or Sertoli cells at either 9 or 36 months of age, nor could hormone levels predict whether spontaneous descent would occur or not.

CONCLUSION

Morphometric and volumetric data show that orchidopexy at 9 months is more beneficial for testicular development than an operation at 3 yr of age. Testicular volume was furthermore shown to reflect germ cell numbers in early childhood, whereas endocrine parameters could not predict cellular structure of the testis or its spontaneous descent.

Vitamins e and C alleviate the germ cell loss and oxidative stress in cryptorchidism when administered separately but not when combined in rats

The antioxidant effects of vitamins C and E on cryptorchidism-induced oxidative stress were investigated in male Sprague-Dawley rats. Forty rats (200-250 g) were randomly divided in a blinded fashion into five groups (n = 8). Group 1 was sham operated and treated with vehicle (corn-oil, 10 mL/kg). Groups 2, 3, 4, and 5 were rendered unilaterally cryptorchid and treated with vehicle (10 mL/kg), vitamin E solution (75 mg/kg), vitamin C solution (1.25 g/kg), and combination of vitamin E (75 mg/kg) and vitamin C (1.25 g/kg) solutions, respectively. Germ cell count, superoxide dismutase (SOD), total protein (TP), and testicular weight (TW) were lower, but malondialdhyde (MDA) was higher in the cryptorchid rats than the sham-operated rats. When administered separately, vitamins C and E increased germ cell count, SOD, TP, and TW but did not reduce MDA in the cryptorchid rats when compared to the vehicle-treated cryptorchid rats. However, there was no significant difference in these parameters between vehicle-treated and combined vitamins C- and E-treated rats. This suggests that vitamins E and C alleviate the germ cell loss and oxidative stress in cryptorchidism when administered separately but not when combined in rats.

Fertility potential in men with a history of congenital undescended testes: a long-term follow-up study

Men with a history of congenital undescended testes (UDT) have an increased risk of fertility problems. Despite no definitive proof, current guidelines recommend early surgical intervention because this may have a positive effect on future fertility potential by preventing degenerative changes of the testes in early life. Also surgical intervention facilitates observability of the testes in view of possible malignancy. We evaluated testicular function in adult men with previous UDT treated at different ages before puberty. A long-term follow-up study of men with previous UDT was performed. Andrological evaluation included medical history taking, physical examination, scrotal ultrasound, determination of reproductive hormones, and semen analysis. Findings were compared with those of a control group of men with normal testicular descent. The influence of age at orchiopexy on future fertility parameters was evaluated in a multivariate regression analysis. 62 men were included of whom seven had had bilateral UDT. Twenty-four patients had had their orchiopexy before the age of 24 months of whom eight men had it before 12 months of age. Forty-eight men had had unsuccessful luteinizing-hormone-releasing-hormone (LHRH) nasal spray treatment during childhood, whereas 14 of 24 men operated before 24 months of age had not received LHRH treatment before orchiopexy. Fertility potential in men with a history of UDT is compromised in comparison with controls. We could not detect any influence of age at orchiopexy on fertility parameters. However, the number of patients operated before the age of 12 months is limited. This study does not support the assumption that early orchiopexy results in better fertility potential.

A pilot study of the association between genetic polymorphisms involved in estrogen signaling and infant male genital phenotypes

Single nucleotide polymorphisms (SNPs) in genes that influence development of the male reproductive tract have been associated with male genitourinary abnormalities. However, no studies have tested the relationship between SNPs and intermediate phenotypes such as anogenital distance (AGD), anoscrotal distance (ASD) and penile width (PW). We tested whether 24 common SNPs in eight genes that influence male genital development were associated with intermediate phenotypes in 106 healthy male infants from the Study for Future Families. We used DNA from buccal smears and linear regression models to assess the relationship between anogenital measurements and SNP genotypes with adjustment for covariates. We found that the rs2077647 G allele, located in the coding region of estrogen receptor alpha (ESR1), was associated with a shorter AGD (P=0.02; -7.3 mm, 95% confidence interval (CI): -11.6 to -3.1), and the rs10475 T allele, located in the 3' untranslated region of activating transcription factor 3 (ATF3), was associated with a shorter ASD (-4.3 mm, 95% CI: -7.2 to -1.4), although this result was not significant (P=0.07) after controlling for multiple comparisons. We observed no association between PW and the SNPs tested. Minor alleles for two SNPs in genes that regulate estrogen signaling during male genital development were associated with AGD and ASD, although the significance of the association was marginal. Our findings suggest that AGD and ASD are influenced by heritable factors in genes known to be associated with frank male genital abnormalities such as hypospadias and cryptorchidism.

Associations between congenital cryptorchidism in newborn boys and levels of dioxins and PCBs in placenta

In animal studies, exposure to dioxins has been associated with disrupted development of the male reproductive system, including testicular maldescent. Some polychlorinated biphenyls (PCBs) have also dioxin-like effects. In addition, one previous case-control study has reported an association between congenital cryptorchidism and colostrum PCB levels. We performed a case-control study to evaluate whether congenital cryptorchidism in boys was associated with increased levels of dioxins or PCBs in placenta reflecting foetal exposure. In addition, associations between placenta levels of these chemicals and reproductive hormone levels in boys at 3 months were studied. Placentas were collected in a Danish-Finnish joint prospective cohort study on cryptorchidism (1997-2001). The boys were examined for cryptorchidism at birth and at 3 months. Altogether, 280 placentas [112 Finnish (56 cases, 56 controls) and 168 Danish (39 cases, 129 controls)] were analysed for 17 toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 37 PCBs (including 12 dioxin-like PCBs). Infant serum samples taken at 3 months were analysed for reproductive hormones. No significant differences between cases and controls were observed in either country in dioxin WHO-TEq levels (median 9.78 vs. 8.47 pg/g fat, respectively, in Finland, and 11.75 vs. 10.88 pg/g fat in Denmark) or PCB WHO-TEq levels (median 2.12 vs. 2.15 pg/g fat in Finland, 2.34 vs. 2.10 pg/g fat in Denmark) or total-TEq levels (median 11.66 vs. 10.58 pg/g fat in Finland, 13.94 vs. 13.00 pg/g fat in Denmark). Placenta WHO-TEq levels of dioxins were not associated with infant reproductive hormone levels at 3 months. In Finland, PCB WHO-TEq levels in placenta associated positively with infant LH levels. WHO-TEq levels of dioxins and PCBs and total-TEq levels were higher in Danish than Finnish samples. In conclusion, no association between placenta levels of dioxins or PCBs and congenital cryptorchidism was found. Significant country differences in chemical levels were observed.

The effect of flutamide on expression of androgen and estrogen receptors in the gubernaculum and surrounding structures during testicular descent

BACKGROUND/PURPOSE

Inguinoscrotal testicular descent is controlled by androgens between embryonic days E16-19, but androgen receptor (AR) and estrogen receptor (ER) locations are unknown. We aimed to find AR, ERα, and ERβ in the gubernaculum and inguinal fat pad (IFP) in normal rats and after flutamide treatment.

METHODS

Sprague-Dawley timed-mated rats were injected with flutamide (75 mg/kg body weight/5% ethanol + oil) on E16-19 or vehicle alone. Male fetuses or pups (5-10/group) were collected at E16; E19; and postnatal (P) days 0, 2, 4, 8. Sections were prepared for hematoxylin and eosin or immunohistochemistry for AR, ERα, and ERβ. Receptor labeling was quantitated as distinct nuclear labeling/100 μm(2) in gubernaculum and IFP.

RESULTS

There was minimal gubernacular AR-labeling until E19, dramatically increasing postnatally. By contrast, at E16-E19 there was significant IFP AR immunoreactivity suppressed by flutamide (P < .05). No ERα expression was observed, but ERβ was expressed in both gubernaculum and IFP, maximally at E16, but unchanged by flutamide.

CONCLUSIONS

During the androgen sensitivity window (E16-19), the gubernaculum contains ERβ but minimal ERα or AR, while the IFP, which is supplied by the genitofemoral nerve, contains abundant AR that are flutamide-sensitive. These results suggest that the IFP could be the site of androgenic action controlling gubernacular development.

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.

The role of the gubernaculum in the descent and undescent of the testis

Testicular descent to the scrotum involves complex anatomical rearrangements and hormonal regulation. The gubernaculum remains the key structure, undergoing the 'swelling reaction' in the transabdominal phase, and actively migrating out of the abdominal wall to the scrotum in the inguinoscrotal phase. Insulin-like hormone 3 (Insl3) is the primary regulator of the first phase, possibly augmented by Müllerian inhibiting substance/anitmüllerian hormone (MIS/AMH), and regression of the cranial suspensory ligament by testosterone. The inguinoscrotal phase is controlled by androgens acting both directly on the gubernaculum and indirectly via the genitofemoral nerve, and release of calcitonin gene-related peptide from its sensory fibres. Outgrowth of the gubernaculum and elongation to the scrotum has many similarities to an embryonic limb bud.Cryptorchidism occurs because of both failure of migration congenitally, and failure of elongation of the spermatic cord postnatally. Germ cell development postnatally is disturbed in congenital cryptorchidism, but our current understanding of germ cell biology suggests that early orchidopexy, around 6 months of age, should provide a significant improvement in prognosis compared with a previous generation. Hormone treatment is not currently recommended. Acquired cryptorchid testes may need orchidopexy once they no longer reach the scrotum, although this remains controversial.

Weak association of anti-sperm antibodies and strong association of familial cryptorchidism/infertility with HLA-DRB1 polymorphisms in prepubertal Ukrainian boys

BACKGROUND

Cryptorchidism is a frequent syndrome occurring in 1-2% of males within the first year of age. Autoimmune reactions, particularly directed to testicular elements and/or spermatozoa have been found to be often associated with cryptorchidism. Therefore we investigated in this study the frequency of HLA class II alleles in order to recognize possible genetic predisposition for antisperm antibodies development in prepubertal boys with diagnosed cryptorchidism in Caucasoid population.

METHODS

Sixty prepubertal boys with cryptorchidism and sixty healthy boys were examined for anti-sperm antibodies by indirect immunobead test as well as for their HLA-DRB1 and -DQB1 alleles using DNA obtained from peripheral blood leukocytes. The typing of HLA-DRB1 and -DQB1 was performed by using PCR-SSP low resolution method.

RESULTS

Allele frequencies of HLA-DRB1 and HLA-DQB1 did not differ between boys with cryptorchidism and control boys. However, weakly significant differences in DRB1*04 (p corrected=0.0475) and DQB1*06 (p corrected=0.0385) were seen between cryptorchid patients with and without AsA, but none of these two patient groups differed significantly in HLA class II frequencies from controls except for AsA-negatives and HLA-DQB1*06 (p corrected=0.0247). On the other hand, comparison of cryptorchid boys with familial cryptorchidism and/or infertility to control boys revealed highly significant (p corrected=0.0006) difference in HLA-DRB*11 frequency, whereas boys with sporadic cryptorchidism did not differ from control. A much weaker, but still significant difference in DRB*11 frequency was also observed between boys with bilateral cryptorchidism and controls (p corrected=0.037), whereas patients with unilateral cryptorchidism were not different from control in frequency of any HLA-DRB1 or -DQB1 allele tested.

CONCLUSIONS

Predisposition to produce anti-sperm antibodies seems to be only weakly associated with HLA class II genes, although this question requires further study on much larger population sample. It is plausible that familial and sporadic cryptorchidism may present distinct genetic background. The same may, to lower extent, apply to bilateral and unilateral cryptorchidism.

Molecular analysis of SNP12 in estrogen receptor α gene in hypospadiac or cryptorchid patients from Northwestern China

OBJECTIVE

To investigate the single nucleotide polymorphism 12 (SNP12) in the estrogen receptor α (ESR1) gene in hypospadiac or cryptorchid patients from Northwestern China.

METHODS

103 patients and 40 controls were analyzed for SNP12 to verify whether this genetic variant was associated with hypospadias or cryptorchidism.

RESULTS

The frequencies of the A allele and homozygote individuals for the A allele of SNP12 in the hypospadiac group were higher than in the control group, respectively (p = 0.011, p = 0.005). The frequency of the A allele of SNP12 in the cryptorchid group was higher than in the control group (p = 0.038). However, no significant difference was observed between the cryptorchid group and control group of homozygote individuals for the A allele of SNP12 (p = 0.070).

CONCLUSIONS

Our results suggested that the A allele of SNP12 may increase the risk of hypospadias or cryptorchidism.

Variation spatiotemporelle de la cryptorchidie et de l'hypospadias au Québec : Une étude exploratoire

RéSUMé:

OBJECTIFS

: La majorité des études effectuées au cours des dernières décennies ont mis en évidence une augmentation du nombre de cas de cryptorchidie et d'hypospadias entre 1970 et 1990. De plus, l'importante variabilité géographique de ces anomalies est bien décrite. Cette étude vise à mesurer la prévalence à la naissance de la cryptorchidie et de l'hypospadias au Québec, à vérifier si ces anomalies sont en augmentation et à en évaluer la répartition interrégionale. MéTHODE :: Une étude épidémiologique descriptive a été réalisée à partir du nombre de garçons de cinq ans et moins hospitalisés pour une cryptorchidie ou un hypospadias au Québec de 1989 à 2004 selon les données du fichier administratif d'hospitalisation MED-ÉCHO. Les données sur les naissances provenaient de l'Institut de la statistique du Québec. RéSULTATS :: La prévalence annuelle moyenne pour 1000 naissances vivantes de sexe masculin est de 19,1 (IC à 95 % : 18,8-19,4) pour la cryptorchidie et 11,4 (IC à 95 % 11,1-11,6) pour l'hypospadias au Québec. Au cours de la période étudiée, la prévalence de cryptorchidie a légèrement diminué, alors que celle de l'hypospadias est demeurée stable. Comparativement à la province du Québec, des régions présentent une prévalence significativement différente de cryptorchidie et/ou d'hypospadias. .

CONCLUSION

: Au Québec, la prévalence de cryptorchidie est en légère diminution alors que celle de l'hypospadias est stable. Des variations régionales significatives sont observables. D'autres études sont nécessaires afin d'évaluer l'hypothèse d'un lien avec les contaminants environnementaux en émergence. L'implantation d'un système de surveillance des anomalies congénitales permettrait une représentation plus valide de la situation.

Etiological classification and clinical assessment of children and adolescents with disorders of sex development

OBJECTIVE

In 2006, the Lawson Wilkins Pediatric Endocrine Society (LWPES) and the European Society for Paediatric Endocrinology (ESPE) published a consensus statement on management of intersex disorders. The aim of our study was to determine the etiological distribution of disorders of sex development (DSD) according to the new DSD classification system and to evaluate the clinical features of DSDs in our patient cohort.

METHODS

We retrospectively reviewed the records of patients followed up during the past three years. The subjects were divided into three etiologic groups according to their karyotypes. The definite diagnoses in each subgroup were established by clinical and laboratory investigations including abdominopelvic imaging as well as basal and stimulated hormone measurements. Molecular genetic testing, except for CYP21A2 gene, could not be performed.

RESULTS

Out of a total of 95 patients, 26 had sex chromosome DSD, 45 had 46,XY DSD and 24 had 46,XX DSD. The most common causes of DSDs were Turner's syndrome (TS), congenital adrenal hyperplasia (CAH) and androgen insensitivity syndrome (AIS). There was a wide variation in age of presentation ranging from 1 day to 17.5 years with a mean of 6.5±6.5 years. The most frequent complaints at presentation were ambiguous genitalia, isolated perineal hypospadias and short stature.

CONCLUSION

The results of our study demonstrate that the new DSD classification system leads to a major change in the distribution of etiological diagnoses of DSDs, which is exemplified by the significant frequencies of TS and vanishing testes syndrome. This alteration expands the clinical spectrum and increases the mean age at diagnosis. However, the most common causes of ambiguous genitalia, such as CAH and AIS, remain unchanged. Further studies using molecular genetic analyses are needed to give a more precise distribution of etiologies of DSDs, especially in 46,XY patients.

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.

[Cryptorchidism: from physiopathology to infertility]

Cryptorchidism is a defect of testicular descent. Hormonal, genetic and environmental factors might also contribute to the aetiology of cryptorchidism and its increased incidence in recent years in industrialised countries. Cryptorchidism itself might be considered a complex disease. This testicular pathology represents the best-characterized risk factor for reduced fertility and testicular cancer. The purpose of this review is to better understand physiopathology and mechanisms of infertility in men with history of cryptorchidism.

Cryptorchidism

Cryptorchidism is a very common anomaly of the male genitalia, affecting 2%-4% of male infants and is more common in premature infants. There are two separate stages of testicular descent. The first stage occurs at 8-15 weeks' gestation in the human fetus and is characterized by enlargement of the genito-inguinal ligament, or gubernaculum, and regression of the cranial suspensory ligament. The testis remains close to the future inguinal region as the fetal abdomen grows. Leydig cells in the testis produce insulin-like hormone 3, which stimulates the caudal gubernaculum to grow and become thicker. Mullerian inhibiting substance may have a role in the first phase of descent by stimulating the swelling reaction in the gubernaculum. The second phase of testicular descent requires migration of the gubernaculum and testis from the inguinal region to the scrotum, between 25 and 35 weeks' gestation. The genitofemoral nerve releases calcitonin gene-related peptide, a neurotransmitter that provides a chemotactic gradient to guide migration. The exact cause of cyrptorchidism remains elusive. Information is mainly derived from animal studies (especially in rodents), which may not extrapolate to the human setting. These findings, however, do have some similarities among mammalian species. The current recommended timing for orchidopexy is between 6 and 12 months of life in an effort to preserve the spermatogonia--the stem cells for subsequent spermatogenesis. Despite surgical treatment by orchidopexy, the long-term outcome still remains problematic and controversial. Impaired fertility (33% in unilateral cases and 66% in bilateral undescended testes) and a cancer risk 5-10 times greater than normal is observed over time. Further research into the cause and management of undescended testes is necessary.

Further insights into the role of T222P variant of RXFP2 in non-syndromic cryptorchidism in two Mediterranean populations

The aetiopathogenesis of isolated cryptorchidism remains largely unknown. Mutation screenings in the most relevant candidate genes for testicular maldescent lead to controversial data in the literature. In particular, the role of the T222P genetic variant of the RXFP2 gene is still debated. Given the controversies, the aim of this study was to provide further data on this genetic variant in two Mediterranean populations. A total of 577 subjects from Spain and 550 from Italy (with and without a history of cryptorchidism) were analysed. The T222P substitution was found in both unilateral and bilateral cases and in a total of 12 controls. These data exclude a clear-cut cause-effect relationship between T222P variant and testicular maldescent. The T222P variant was found at a similar frequency in both cases and controls in the Spanish population, whereas in Italy, the frequency of T222P resulted significantly higher in the cryptorchid group (p = 0.031). The observed difference between the two countries and the highly variable phenotypic expression of the T222P variant may depend on the genetic background or on environmental conditions. The haplotype analysis of the RXFP2 gene in T222P carriers and their parents showed that this variant is linked to the previously inferred C-C-G-A-13 haplotype and consequently provides further support to the 'founder effect' hypothesis. In conclusion, our data indicate that T222P is a frequent variant in the Spanish population with no pathogenic effect. Although in Italy it seems to confer a mild risk (odds ratio = 3.17, 95% confidence interval: 1.07-9.34) to cryptorchidism, the screening for this variant for diagnostic purposes is not advised because of the relatively high frequency of control carriers (1.4% of Italian men without a history of cryptorchidism).

Cryptorchidism: pathogenesis, diagnosis, treatment and prognosis

Cryptorchidism is a common genital anomaly diagnosed at birth or during childhood. Genetic and/or environmental factors that alter expression or function of hormones crucial for testicular descent, insulin-like 3, and testosterone, may contribute to cryptorchidism. When identified at birth, surgical treatment is indicated by 6 months of age if testes fail to descend, or at the time of diagnosis in older children. A laparoscopic approach is preferred for abdominal testes. Early surgical therapy may reduce the risk of subfertility and/or malignancy.

Natural history and long-term testicular growth of acquired undescended testis after spontaneous descent or pubertal orchidopexy

OBJECTIVE

To assess prospectively the natural history and long-term testicular growth of acquired undescended testis (UDT) after spontaneous descent or pubertal orchidopexy in case of nondescent.

PATIENTS AND METHODS

From 1996 until 2008, 391 boys with 464 acquired UDT were included in the study. In accordance with Dutch consensus on non-scrotal testes, spontaneous descent at puberty was awaited; if this did not take place, orchidopexy was performed at puberty. Acquired UDT was defined as a testis previously residing in the scrotum that can no longer be manipulated into a stable scrotal (high scrotal) or nonscrotal (inguinal, impalpable) position. After referral, testis position, testis volume and puberty stage were monitored annually until adolescence. Testis volume was assessed using an orchidometer and compared with the Dutch standard. All investigations were carried out by the same physician (W.H.). Of these boys, 84 (mean age 12.9 years, range 6.4-21.3) were also clinically assessed by a second physician (J.G.), unaware of the results of the first examination. In addition, these boys were assessed with testicular ultrasonography, carried out by both physicians.

RESULTS

Currently the mean (range) follow-up is 4.7 (0.1-12.0) years, and 253 acquired UDT have reached the scrotum. In 196 of these 253 cases (77.5%), there was spontaneous descent at puberty (mean age at descent 12.9 years, range 9.8-16.9); in the other 57 cases (22.5%), pubertal orchidopexy was required due to nondescent; five cases required orchidectomy. Of the 494 testis volume measurements after spontaneous descent, 458 (92.7%) were at ≥10th centile for age, of which 311 (63.0%) were ≥50th centile, and 107 (21.7%) ≥90th centile. After pubertal orchidopexy for nondescent, of the 85 measurements, 79 (92.9%) were at ≥10th centile, 53 (62.4%) ≥50th centile and 12 (14.1%) ≥90th centile. In unilateral cases, after spontaneous descent 174 of the 294 (59.2%) retained testes were found to be smaller than their counterpart and 90 of 294 (30.6%) were equal in size. After pubertal orchidopexy in unilateral cases, 40 of the 51 (78.4%) testes were smaller, and nine (17.6%) were equal in size. There was a strong correlation between both investigators for the measurement of testicular volume by orchidometer, and for the main investigator (W.H.) between his measurements by ultrasonography and the Prader orchidometer.

CONCLUSION

Acquired UDT has a 77.5% tendency of spontaneous descent at puberty. In nearly all cases, after spontaneous descent as well as after pubertal orchidopexy, long-term testicular growth is within the normal range.

An insight into testis and gubernaculum dynamics of INSL3 - RXFP2 signalling during testicular descent in the dog

Insulin-like 3 (INSL3) plays a prominent role in male development and is supposed to induce the growth of the gubernaculum testis (g.t.), thus being directly involved in testicular descent in humans and rodents. This happens through activation of the RXFP2 receptor (GREAT or LGR8). The INSL3–RXFP2 complex is reputed to play an additional paracrine role in the testis, possibly acting as part of an autocrine feedback loop. The present work provides evidence of the immunolocalisation of INSL3 in the Leydig cells of canine fetuses and of the expression of RXFP2 receptor in different tissues of the g.t. of the same specimens. RXFP2 was localised at the cell membrane of g.t. muscle and connective cells, as well as in the epithelial cells of the developing excurrent ducts. Notably, RXFP2 immunoreactivity of the g.t. was limited to fetuses at ~35–45 days of gestation, which is also the fetal period when the endocrine compartment of the dog testis is active endocrinologically, as confirmed by the anti-P450c17 and anti-INSL3 immunoreactivities of the fetal Leydig cells, and by anti-Müllerian hormone immunoreactivity of the Sertoli cells. The same immunoreactivities were also evaluated in the testes of cryptorchid dogs of different ages. RXFP2 immunoreactivity was absent from genital tracts of cryptorchid testes and g.t. remnants.

Phthalate levels and low birth weight: a nested case-control study of Chinese newborns

OBJECTIVE

To assess maternal-fetal exposure to phthalates and investigate whether in utero phthalate exposure is associated with low birth weight (LBW).

STUDY DESIGN

A total of 201 newborn-mother pairs (88 LBW cases and 113 controls) residing in Shanghai were enrolled in this nested case-control study during 2005-2006. Maternal blood, cord blood, and meconium specimens were collected and analyzed for phthalates by high-performance liquid chromatography-mass spectrometry. Nonparametric tests were used to compare demographic characteristics in cases and controls. Conditional logistic regression and Spearman correlation were used to analyze the association between phthalate exposure and LBW.

RESULTS

No significant differences in gestational age, prepregnancy body mass index, prenatal care, vitamin supplementation, or socioeconomic levels were found between the LBW and control infants. More than 70% of the biosamples had quantifiable levels of phthalates, with higher levels in the LBW infants compared with the controls. Prenatal di-n-butyl phthalate (DBP) exposure was associated with LBW, and di-2-ethylhexyl phthalate (DEHP) was negatively associated with birth length. After adjusting for the potential confounders, DBP concentrations in the highest quartile were associated with an increased risk of LBW.

CONCLUSIONS

Newborns in China are ubiquitously exposed to phthalates; significantly higher phthalate levels were detected in LBW cases compared with controls. In utero DBP and DEHP exposures were associated with LBW in a dose-dependent manner. Prenatal phthalate exposure may be a risk factor for LBW.

Acquired cryptorchidism is frequent in infancy and childhood

Accurate prevalence data for acquired cryptorchidism are currently sparse and systematic prospective studies have not yet been reported. Our aim was to determine the prevalence of testicular ascent in childhood. In a prospective longitudinal population-based child cohort from Copenhagen, Denmark (1997-2007), testicular position was examined according to a standardised protocol in a total of 1072 boys, at birth (n = 1051), at 3 months (n = 983), 18 months (n = 888), 36 months (n = 790) and again once between 4 1/2 and 10 years of age (n = 509). Ascensus testis was defined as ascent of the testis into a cryptorchid position after normal scrotal position at birth. A congenital cryptorchid testis with spontaneous postnatal descent followed by recurrence of cryptorchidism was named recurrent cryptorchidism. Ascensus testis occurred in 0.2%, 0.6% and 0.6% of boys at 3, 18 and 36 months of age respectively. When including recurrent cryptorchidism the prevalence was 0.2%, 1.2% and 0.8% respectively. Ascensus testis accounts for 58% of all cases of cryptorchidism (congenital and acquired) at 18 months, 71% at 36 months and thereafter 69%. Ascensus testis accounts for more than half of cryptorchid testes seen in childhood and occurs in both previously scrotal and cryptorchid testes. We therefore recommend that all boys should have testis position checked regularly during childhood, at least up to 3 years of age.

Alcohol binge drinking during pregnancy and cryptorchidism

BACKGROUND

Recent studies have suggested gestational weeks 8-14 as a time window of particular importance to the intrauterine development of the male genitalia, and prenatal exposure to alcohol is under suspicion as a risk factor for cryptorchidism. We examined if prenatal exposure to alcohol, and especially binge drinking, during the suggested programming window is associated with an increased risk of cryptorchidism.

METHODS

The authors used data on 41 268 live born singleton boys of mothers who were enrolled into the Danish National Birth Cohort in 1996-2002. During early childhood, 1598 cases of cryptorchidism were identified and 398 of these were orchiopexy verified. Maternal alcohol consumption including number and timing of binge drinking episodes was assessed in two computer-assisted telephone interviews around gestational weeks 17 and 32. Adjusted hazard ratios (HRs) of cryptorchidism were estimated by Cox regression.

RESULTS

Average weekly alcohol consumption as well as frequency of binge drinking at any time during pregnancy was not associated with risk of cryptorchidism. Binge drinking in gestational weeks 7-15 was associated with a slightly increased risk of cryptorchidism with adjusted HRs between 1.03 and 1.66.

CONCLUSION

Prenatal exposure to alcohol-measured as average intake as well as frequency and timing of binge drinking-was not associated with cryptorchidism. Our findings, however, do not rule out that binge drinking during the suggested male programming window may increase the risk of cryptorchidism.

Reproductive outcome of men with azoospermia due to cryptorchidism using assisted techniques

The aetiology of cryptorchidism is still undiscernible in the majority of cases. It has long been argued that cryptorchidism reflects a primary testicular maldevelopment, where the contralateral scrotal testis also suffers from aspermatogenesis and low spermatogonia count. The aim of the study was to determine the reproductive outcome of ex-cryptorchid men with azoospermia post-orchidopexy after testicular sperm extraction (TESE) and intracytoplasmatic sperm injection (ICSI). In a retrospective analysis, we compared the sperm retrieval, fertilization, pregnancy and live birth rates after ICSI of consecutive ex-cryptorchid azoospermic patients (n = 15) undergoing TESE between Jan 2000 and Dec 2007 vs. non-cryptorchid azoospermic men (n = 142). Sperm retrieval rate of ex-cryptorchid men by TESE (66%) was comparable with non-cryptorchid men (47%) (p = 0.15) despite significantly higher FSH levels (30.7 +/- 25.4 vs. 17.9 +/- 14.8 respectively) (p = 0.018) and a more prevalent histopathology diagnosis of aspermatogenesis (75% vs. 40%, p = 0.046). Fertilization (43.3%), pregnancy (30%) and live birth (20%) rates after TESE-IVF-ICSI in the ex-cryptorchid group were not different from the non-cryptorchid group (48.7, 43 and 29%, p = 0.26, p = 0.21, p = 0.29 respectively). We conclude that the reproductive outcome of ex-cryptorchid men with azoospermia post-orchidopexy employing TESE-IVF-ICSI is comparable with non-cryptorchid azoospermic men.

Factors controlling testis descent

Descent of the testis from an intra-abdominal site in foetal life to an extracorporeal location after birth is a mandatory developmental process to ensure that the mature testis promotes normal spermatogenesis. The two phases of transabdominal and inguinoscrotal descent occur approximately during the first and last thirds of gestation respectively. Key anatomical events to release the testis from its urogenital ridge location and to guide the free gonad into the scrotum are the degeneration of the cranio-suspensory ligament and a thickening of the gubernaculum. Androgens play a role in both these processes, particularly with respect to enabling the testis to traverse the inguinal canal in the final phase of descent. Experiments in animals suggest that androgens mediate this effect via the release of calcitonin gene-related peptide by the genitofemoral nerve, but direct evidence for such a mechanism is lacking in humans. The transabdominal phase of descent is under the control of insulin-like 3 (INSL3), a product of the Leydig cells. Definitive evidence of its role in rodent testis descent is illustrated by the phenotype of bilateral cryptorchidism in Insl3-/- null mice. Circulating levels of INSL3 are higher in boys at puberty, are undetectable in girls and are lower in boys with undescended testes. A minority also have a mutation either in the INSL3 gene or affecting its receptor gene, relaxin/insulin-like family peptide receptor 2 (LGRF8). Other factors that may play a role in testis descent include the anti-Mullerian hormone and members of the HOX gene family. Evidence that the prevalence of undescended testis may be increasing provides a phenotypic readout for the effects of postulated chemicals in the environment interfering in some way with the action of factors that control testis descent. Epidemiological studies point to profound geographical variations in prevalence in countries such as Denmark and Finland. Associations have been found with levels of chemicals labelled as endocrine disruptors being higher in breast milk samples from mothers with cryptorchid boys when compared with controls. The adverse effects of these compounds (e.g. bisphenol A) can be replicated in the offspring of dams exposed during pregnancy. A sensitive marker of an anti-androgen effect of a compound is a reduction in the anogenital distance, an anthropometric measurement that is significantly greater in males compared with females. The observation of an association between the anogenital distance in infant boys and the level of pesticides in the urine of their mothers in late gestation indicates that this has the potential to be a useful surrogate marker of the effects of environmental chemicals on testis descent in human population studies. The rightful place for the testis at birth is in the scrotum in order to provide the temperature differential essential for normal spermatogenesis. Appropriate screening programmes and early surgical intervention are the prerequisites to ensure optimal fertility in adulthood and a considerably lessened risk of testis cancer.

Cryptorchidism concordance in monozygotic and dizygotic twin brothers, full brothers, and half-brothers

OBJECTIVE

To study concordance rates of cryptorchidism (undescended testis) in pairs of boys with varying family structure, to evaluate the risk contribution from the intrauterine environment and genetic factors.

DESIGN

Population based study of 1,024,500 Danish boys born from January 1, 1973 to December 31, 2004. Classic twin method and computerized square dance design.

SETTING

Hospitals and outpatient clinics.

PATIENT(S)

Six groups of boy pairs: boys with no relation, paternal half-brothers, maternal half-brothers, full brothers, dizygotic twin brothers, and monozygotic twin brothers.

INTERVENTION(S)

Observational study.

MAIN OUTCOME MEASURE(S)

Status on each individual regarding cryptorchidism and orchiopexy from the Danish National Patient Register.

RESULT(S)

Concordance rates of cryptorchidism in the groups were as follows: boys with no relation 3.2% (95% confidence interval 2.7%-3.6%), paternal half-brothers 3.4% (2.3%-4.7%), maternal half-brothers 6.0% (4.5%-7.7%), full brothers 8.8% (8.3%-9.8%), dizygotic twin brothers 24.1% (16.0%-33.6%), and monozygotic twin brothers 27.3% (15.5%-41.2%).

CONCLUSION(S)

The concordance rate was higher in maternal than in paternal half-brothers, and much higher but of equal magnitude in both twin groups. The findings strongly support that the intrauterine environment and maternal inheritance are contributing to the occurrence of cryptorchidism.

Undescended testis: current theories of etiology

PURPOSE OF REVIEW

Nonsyndromic cryptorchidism or undescended testis is a structural defect of infants and children whose etiology is unknown but likely related to a combination of genetic susceptibility and environmental factors. This review will focus on factors that may contribute to the etiology of this common and complex disease.

RECENT FINDINGS

The incidence of cryptorchidism is estimated to be 2-4% or higher in some populations. Data suggesting increasing prevalence are conflicting, possibly related to problems with diagnostic accuracy. Increased risk of cryptorchidism in first-degree relatives suggests a significant genetic contribution to susceptibility. Sequence variants within key candidate genes, such as insulin-like 3 and relaxin/insulin-like family peptide receptor 2, in cases of nonsyndromic cryptorchidism are infrequent and of unclear significance. Epidemiological data suggest that fetal growth restriction, maternal factors such as smoking, alcohol use and gestational diabetes, and exposure to environmental chemicals may contribute to risk, although data are inconsistent.

SUMMARY

The available evidence suggests a significant genetic contribution to cryptorchidism susceptibility that may be modulated by environmental risk factors. Additional studies are needed to define these factors, their complex interaction and their effects on testicular development and descent.

Role of hormones, genes, and environment in human cryptorchidism

Cryptorchidism is the most frequent congenital birth defect in male children (2-4% in full-term male births), and it has the potential to impact the health of the human male. In fact, although it is often considered a mild malformation, it represents the best-characterized risk factor for reduced fertility and testicular cancer. Furthermore, some reports have highlighted a significant increase in the prevalence of cryptorchidism over the last few decades. Etiology of cryptorchidism remains for the most part unknown, and cryptorchidism itself might be considered a complex disease. Major regulators of testicular descent from intraabdominal location into the bottom of the scrotum are the Leydig-cell-derived hormones testosterone and insulin-like factor 3. Research on possible genetic causes of cryptorchidism has increased recently. Abundant animal evidence supports a genetic cause, whereas the genetic contribution to human cryptorchidism is being elucidated only recently. Mutations in the gene for insulin-like factor 3 and its receptor and in the androgen receptor gene have been recognized as causes of cryptorchidism in some cases, but some chromosomal alterations, above all the Klinefelter syndrome, are also frequently involved. Environmental factors acting as endocrine disruptors of testicular descent might also contribute to the etiology of cryptorchidism and its increased incidence in recent years. Furthermore, polymorphisms in different genes have recently been investigated as contributing risk factors for cryptorchidism, alone or by influencing susceptibility to endocrine disruptors. Obviously, the interaction of environmental and genetic factors is fundamental, and many aspects have been clarified only recently.