Association between altered placental human chorionic gonadotrophin (hCG) production and the occurrence of cryptorchidism: a retrospective study

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Low placental weight may be involved in the etiology of congenital cryptorchidism in neonatal boys

INTRODUCTION

Several factors have been reported to be associated with the etiology of cryptorchidism; however, clear evidence regarding the risk factors for cryptorchidism is elusive. In the present study, we evaluated the clinical characteristics of cryptorchidism using the common neonatal intensive-care unit (NICU) database of the National Hospital Organization and explored one of possible factors associated with the development of cryptorchidism.

METHODS

A total of 7882 male neonates were included in this study. We separated them into two groups: those without cryptorchidism (n = 7852) and those with cryptorchidism (n = 30) at the time of discharge from the NICU. Cryptorchidism was defined as a condition in which the testis was located out of the scrotum on the route of descent at the time of NICU discharge. The associations between cryptorchidism and the maternal, placental, and neonatal information were analyzed. Analyses were performed statistically to compare nominal variables between the groups using Fisher's direct establishment calculation method and logistic regression analyses.

RESULTS

Univariate analyses showed the placental weight <10% tile (odds ratio 3.31, 95% confidence interval [CI] 1.18-8.64), birth height <-2 standard deviations (SD) (odds ratio 3.65, 95% CI 0.92-10.6), birth weight <-2SD (odds ratio 4.06, 95% CI 1.55-9.51), and small for gestational age (odds ratio 3.82, 95% CI 1.46-8.97) were significantly associated with the development of cryptorchidism. Multivariate analyses showed that placental weight <10th percentile (odds ratio 2.86, 95% CI 1.11-7.44) was significantly associated with the development of cryptorchidism.

DISCUSSION

Although, this study population was limited to infants admitted to the ICU, the data indicated a possible association between low placental weight and the development of cryptorchidism in neonatal boys.

A toolkit for the application of placental-fetal molecular biomarkers in epidemiologic studies of the fetal origins of chronic disease

Purpose of review

In this review, we provide essential background knowledge and an analytical framework for the application of placental-fetal molecular biomarkers in fetal origins chronic disease epidemiology. The widely available and highly quantitative placental hormone human chorionic gonadotropin (hCG) is used as an example. hCG is currently used for diagnosing fetal genetic disorders; yet it can and should be expanded to understanding the fetal origins of chronic diseases. We provide justification and methods to do this.

Recent findings

Ten papers published in the last 5 years were identified with supportive findings relevant to the application of biomarkers of hCG in epidemiologic studies on the developmental origins of health and disease (DOHaD).

Summary

There is increasing and consistent evidence that placental-fetal biomarkers may be highly informative in observational studies, as exemplified by hCG, with the correct approaches for measurement and data analysis.

The G178A polymorphic variant of INSL3 may be linked to cryptorchidism among Egyptian pediatric cohort

Cryptorchidism (CO) is a genital disorder of multifactorial etiology, with serious remote complications. Mutations in insulin-like 3 hormones (INSL3) G/A variant remain a matter of inquiry. We aimed to investigate the association between G178A-INSL3 polymorphism and undescended testis in a cohort of Egyptian children. In this study, a total of 160 children, including 80 cases with primary non-syndromic undescended testes and 80 healthy children with normal external genitalia as controls, both, were analyzed after detailed history, physical examination and imaging for mutations of G178A polymorphism of INSL3 gene by restriction fragment length polymorphism (RFLP) technique. We found most of the undescended testes were inside the inguinal canal mainly on the left side. Genetic analysis revealed that the mutant A allele of G178A INSL3 variant was significantly detected in the patient group with a frequency of 26.2% against 12.5% for control subjects, especially among cases with an evident family history of similar cases as shown by p value = 0.001 and odd's ratio (CI95%) of 0.13 (0.04-0.723). In conclusion, G178A-INSL3 gene polymorphism could be a susceptibility factor for testicular maldescent in Egyptian children. Also, family history of similar cases was considered as significant predictive risk for cryptorchidism, added to the shared genetic links to consanguinity in our locality.

Impaired serum inhibin-B and number of germ cells in boys with cryptorchidism following heavily gestational maternal smoking

PURPOSE

A meta-analysis including 11,900 cases showed that maternal gestational smoking was associated with increased risk of cryptorchidism. The aim of study was to investigate whether a hormone profile of cryptorchid boys and a supplementing histopathological evaluation of testicular biopsies could add detailed knowledge to the impact of maternal gestational smoking on pathogenesis of cryptorchidism.

METHODS

601 cryptorchid boys aged 4 months to 14 years old were included. Because normal hormones have a pronounced age dependency, we compared results from boys whose mothers had smoked heavily (>10 cigarettes/day) during pregnancy with age matched cryptorchid controls of nonsmoking mothers (1:6). We studied: birthweight, germ-cell number/tubular cross section, frequency of germ cells positive for placental-like alkaline phosphatase (PLAP), gonadotropins and inhibin-B.

RESULTS

501 boys were sons of nonsmokers, 72 boys of intermittent smokers and 28 boys of heavy smokers. 39%, 44% and 61% respectively had bilateral cryptorchidism. Compared to age-matched cryptorchid controls of nonsmoking mothers, sons of heavy smokers had lower birthweight (p = 0.006), germ-cell number/tubular cross section (p = 0.009), frequency of germ cells positive for PLAP (p = 0.037) and inhibin-B (p = 0.042).

CONCLUSIONS

All findings could be associated with placental dysfunction with altered human chorionic gonadotropin production well described in women smoking during pregnancy.

TYPE OF STUDY

Prognosis study (prospective cohort study with >80% follow-up).

LEVEL OF EVIDENCE

Level 1.

Postnatal Testicular Activity in Healthy Boys and Boys With Cryptorchidism

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

Placental Weight and Risk of Cryptorchidism and Hypospadias in the Collaborative Perinatal Project

Cryptorchidism and hypospadias are the most common congenital anomalies of the genitourinary tract in males, but their etiology remains unclear. Placental insufficiency has been suggested to be linked to both conditions. Placental weight is a commonly used proxy measure for placental insufficiency; thus, we examined placental weight and other placental characteristics in relation to cryptorchidism and hypospadias in the Collaborative Perinatal Project, a US mother-child cohort study. Pregnant women were recruited between 1959 and 1965. The analysis contrasted boys with cryptorchidism (n = 413) and boys with hypospadias (n = 145) with boys without cryptorchidism (n = 23,799) and boys without hypospadias (n = 22,326). Odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. In categorical analyses in which the middle tertile was the referent, cryptorchidism was inversely associated with placental weight (odds ratio = 0.66, 95% confidence interval: 0.46, 0.95) among white boys and positively associated with the lowest tertile of placental weight among black boys (odds ratio = 1.70, 95% confidence interval: 1.11, 2.59). We conclude that lower placental weight may be related to risk of cryptorchidism. Further investigation of placental functioning may offer insights into the etiology of cryptorchidism.

Post-operative use of human chorionic gonadotrophin (u-hCG) inpatients treated for intrabdominal unilateral undescended testes

OBJECTIVE

To report our experience with post-operative use of human chorionic gonadotrophin to achieve higher testicular volume and function, respect to untreated patients.

MATERIALS AND METHODS

A prospective study was done using subjects who underwent orchidopexy between Sptember 2010 and September 2016 for unilateral intrabdominal undescended testes. All patients were treated by the same surgeon with laparoscopic one-stage Fowler-Stephens technique. After surgery (2 weeks) those patient parents who accepted to use hormonal therapy, had to follow a 6 weeks scheme. Patients received subcutaneous 500 UI (Gonasi-HP) weekly. A follow-up was performed at the end of therapy and 6 months later. Testicular volume was measured at each visit by ultrasound and by sonoelastography and compared with the untreated ones.

RESULTS

Forty-five patients were enrolled and treated with a mean age of 18.0±9.7 months. 32 patients received post-operative hormonal therapy. There were no cases of adverse effects nor droupout. All patients completed follow-up. There were no cases of testicular atrophy in both groups. At 6 months among treated patients 26 (81%) subjects achieved normal testicular size while the other had still smaller volume. Among untreated patients, 6 (46%) subject achieved normal testicular size (P < 0.05).

CONCLUSION

Despite the role of hormonal therapy is still under discussion, especially for post-operative treatment, our results suggest that it is safe and useful to improve testicular volume and morphology; treated testes have also a good stiffness respect to untreated testes.

Pretreatment with Human Chorionic Gonadotropin Protects the Neonatal Brain against the Effects of Hypoxic-Ischemic Injury

INTRODUCTION

Though the human fetus is exposed to placentally derived human chorionic gonadotropin (hCG) throughout gestation, the role of hCG on the fetal brain is unknown. Review of the available literature appears to indicate that groups of women with higher mean levels of hCG during pregnancy tend to have offspring with lower cerebral palsy (CP) risk. Given that newborn cerebral injury often precedes the development of CP, we aimed to determine whether hCG may protect against the neurodegenerative effects of neonatal brain injury.

METHODS

We utilized the Rice-Vannucci model of neonatal cerebral hypoxia-ischemia (HI) in postnatal day 7 mice to examine whether intraperitoneal administration of hCG 15-18 h prior, 1 h after or immediately following HI decrease brain tissue loss 7 days after injury. We next studied whether hCG has pro-survival and trophic properties in neurons by exposing immature cortical and hippocampal neurons to hCG in vitro and examining neurite sprouting and neuronal survival prior and after glutamate receptor-mediated excitotoxic injury.

RESULTS

We found that intraperitoneal injection of hCG 15 h prior to HI, but not at or 1 h after HI induction, resulted in a significant decrease in hippocampal and striatal tissue loss 7 days following brain injury. Furthermore, hCG reduced N-methyl-d-aspartate (NMDA)-mediated neuronal excitotoxicity in vitro when neurons were continuously exposed to this hormone for 10 days or when given at the time and following neuronal injury. In addition, continuous in vitro administration of hCG for 6-9 days increased neurite sprouting and basal neuronal survival as assessed by at least a 1-fold increase in MAP2 immunoreactivity and a 2.5-fold increase in NeuN + immunoreactivity.

CONCLUSION

Our findings suggest that hCG can decrease HI-associated immature neural degeneration. The mechanism of action for this neuroprotective effect may partly involve inhibition of NMDA-dependent excitotoxic injury. This study supports the hypothesis that hCG during pregnancy has the potential for protecting the developing brain against HI, an important CP risk factor.

An Investigation of the Single and Combined Phthalate Metabolite Effects on Human Chorionic Gonadotropin Expression in Placental Cells

BACKGROUND

Observational studies have reported associations between maternal phthalate levels and adverse outcomes at birth and in the health of the child. Effects on placental function have been suggested as a biologic basis for these findings.

OBJECTIVE

We evaluated the effects of phthalates on placental function in vitro by measuring relevant candidate genes and proteins.

MATERIALS AND METHODS

Human trophoblast progenitor cells were isolated at 7-14 wk of pregnancy (two female and three male concepti), and villous cytotrophoblast cells (vCTBs) were isolated at 15-20 wk (three female and four male concepti). Cells were cultured in vitro with four phthalate metabolites and their combination at concentrations based on levels found previously in the urine of pregnant women: mono-n-butyl (MnBP, 200 nM), monobenzyl (MBzP, 3μM), mono-2-ethylhexyl (MEHP, 700 nM), and monoethyl (MEP, 1.5μM) phthalates. mRNA levels of CGA, CGB, PPARG, CYP19A1, CYP11A1, PTGS2, EREG, and the intracellular β subunit of human chorionic gonadotropin (hCGβ) and peroxisome proliferator activated receptor γ (PPARγ) were measured in the cellular extracts, and protein levels for four forms of secreted hCG were measured in the conditioned media.

RESULTS

Previously reported associations between maternal phthalates and placental gene expression were reproduced experimentally: MnBP with CGA, MBzP with CYP11A1, and MEHP with PTGS2. CGB and hCGβ were up-regulated by MBzP. In some cases, there were marked, even opposite, differences in response by sex of the cells. There was evidence of agonism in female cells and antagonism in male cells of PPARγ by simultaneous exposure to multiple phthalates.

CONCLUSIONS

Concentrations of MnBP, MBzP and MEHP similar to those found in the urine of pregnant women consistently altered hCG and PPARγ expression in primary placental cells. These findings provide evidence for the molecular basis by which phthalates may alter placental function, and they provide a preliminary mechanistic hypothesis for opposite responses by sex. https://doi.org/10.1289/EHP1539.

Risk factors for cryptorchidism

Undescended testis - known as cryptorchidism - is one of the most common congenital abnormalities observed in boys, and is one of the few known risk factors for testicular cancer. The key factors that contribute to the occurrence of cryptorchidism remain elusive. Testicular descent is thought to occur during two hormonally-controlled phases in fetal development - between 8-15 weeks (the first phase of decent) and 25-35 weeks gestation (the second phase of descent); the failure of a testis to descend permanently is probably caused by disruptions to one or both of these phases, but the causes and mechanisms of such disruptions are still unclear. A broad range of putative risk factors have been evaluated in relation to the development of cryptorchidism but their plausibility is still in question. Consistent evidence of an association with cryptorchidism exists for only a few factors, and in those cases in which evidence seems unequivocal the factor is likely to be a surrogate for the true causal exposure. The relative importance of each risk factor could vary considerably between mother-son pairs depending on an array of genetic, maternal, placental and fetal factors - all of which could vary between regions. Thus, the role of causative factors in aetiology of cryptorchidism requires further research.

Maternal first trimester serum levels of free-beta human chorionic gonadotrophin and male genital anomalies

STUDY QUESTION

Are maternal first trimester levels of serum free-beta hCG associated with the development of hypospadias or undescended testis (UDT) in boys?

SUMMARY ANSWER

Overall, first trimester maternal levels of serum free-beta hCG are not associated with hypospadias or UDT. However, elevated levels were found in severe phenotypes (proximal hypospadias and bilateral UDT) suggesting an altered pathway of hormonal release in early pregnancy.

WHAT IS KNOWN ALREADY

Human chorionic gonadotrophin peaks in first trimester of pregnancy stimulating fetal testosterone production, which is key to normal male genital development. Endocrine-disrupting insults early in pregnancy have been associated with increased risk of common genital anomalies in males such as hypospadias and UDT. One plausible etiological pathway is altered release of hCG.

STUDY DESIGN, SIZE, DURATION

We conducted a record-linkage study of two separate populations of women attending first trimester aneuploidy screening in two Australian states, New South Wales (NSW) and Western Australia (WA), in 2006-2009 and 2001-2003, respectively.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Included were women who gave birth to a singleton live born male infant. There were 12 099 boys from NSW and 10 518 from WA included, of whom 90 and 77 had hypospadias; and 107 and 109 UDT, respectively. Serum levels of free-beta hCG were ascertained from laboratory databases and combined with relevant birth outcomes and congenital anomalies via record linkage of laboratory, birth, congenital anomalies and hospital data. Median and quartile levels of gestational age specific free-beta hCG multiple of the median (MoM) were compared between affected and unaffected boys. Logistic regression was used to evaluate the association between levels of free-beta hCG MoM and hypospadias or UDT, stratified by suspected placental dysfunction and co-existing anomalies. Where relevant, pooled analysis was conducted.

MAIN RESULTS AND THE ROLE OF CHANCE

There was no difference in median hCG levels amongst women with an infant with hypospadias (NSW = 0.88 MoM, P = 0.83; WA = 0.84 MoM, P = 0.76) or UDT (NSW = 0.89 MoM, P = 0.54; WA = 0.95 MoM, P = 0.95), compared with women with an unaffected boy (NSW = 0.92 MoM; WA = 0.88 MoM). Low (<25th centile) or high (>75th centile) hCG levels were not associated with hypospadias or UDT, nor when stratifying by suspected placental dysfunction and co-existing anomalies. However, there was a tendency towards high levels for severe types, although confidence intervals were wide. When combining NSW and WA results, high hCG MoM levels (>75th centile) were associated with increased risk of proximal hypospadias (odds ratio (OR) 4.34; 95% CI: 1.08-17.4) and bilateral UDT (OR 2.86; 95% CI: 1.02-8.03).

LIMITATIONS, REASONS FOR CAUTION

There were only small numbers of proximal hypospadias and bilateral UDT in both cohorts and although we conducted pooled analyses, results reported on these should be interpreted with caution. Gestational age by ultrasound may have been inaccurately estimated in small and large for gestational age fetuses affecting hCG MoM calculation in those pregnancies. Despite the reliability of our datasets in identifying adverse pregnancy outcomes, we did not have pathology information to confirm tissue lesions in the placenta and therefore our composite outcome should be considered as a proxy for placental dysfunction.

WIDER IMPLICATIONS OF THE FINDINGS

This is one of the largest population-based studies examining the association between maternal first trimester serum levels of free-beta hCG and genital anomalies-hypospadias and UDT; and the first to compare specific phenotypes by severity. Overall, our findings does not support the hypothesis that alteration in maternal hCG levels is associated with the development of male genital anomalies; however, high hCG free-beta levels found in severe types suggest different underlying etiology involving higher production and secretion of hCG. These findings require further exploration and replication.

STUDY FUNDING/COMPETING INTERESTS

This work was funded by the National Health and Medical Research Council (NHMRC) grant APP1047263. N.N. is supported by a NHMRC Career Development Fellowship APP1067066. C.B. was supported by a NHMRC Principal Research Fellowship #634341. The funding agencies had no role in the design, analysis, interpretation or reporting of the findings. There are no competing interests.

TRIAL REGISTRATION NUMBER

Not applicable.

Placental Weight and Male Genital Anomalies: A Nationwide Danish Cohort Study

The most consistently reported risk indicators for the male genital anomalies cryptorchidism and hypospadias are prematurity and low birth weight. Placental dysfunction has been hypothesized as a possible underlying cause, and an association between placental weight at birth and hypospadias has been indicated. In a population-based cohort of 388,422 Danish singleton boys born alive (1997-2008), we studied the association between placental weight and cryptorchidism and hypospadias. Missing data were handled with multiple imputation, and we estimated hazard ratios by means of Cox regression models. During follow-up, 1,713 boys were diagnosed with hypospadias and 6,878 with cryptorchidism (3,624 underwent corrective surgery). We observed an association between low placental weight and risk of both genital anomalies. Boys with a placental weight in the lowest decile (<10%) had higher risks of both cryptorchidism (hazard ratio = 1.52, 95% confidence interval: 1.31, 1.76) and hypospadias (hazard ratio = 1.97, 95% confidence interval: 1.59, 2.45) than boys in the reference decile (50.0-59.9%). In conclusion, we found higher risks of both genital malformations in boys born with a low placental weight. The relationship seemed stronger for hypospadias than for cryptorchidism. Taken together, our data support a role for placental dysfunction in the etiology of these anomalies.

Human Chorionic Gonadotropin Partially Mediates Phthalate Association With Male and Female Anogenital Distance

CONTEXT

Prenatal exposure to phthalates disrupts male sex development in rodents. In humans, the placental glycoprotein hormone human chorionic gonadotropin (hCG) is required for male development, and may be a target of phthalate exposure.

OBJECTIVE

This study aimed to test the hypothesis that phthalates disrupt placental hCG differentially in males and females with consequences for sexually dimorphic genital development.

DESIGN

The Infant Development and Environment Study (TIDES) is a prospective birth cohort. Pregnant women were enrolled from 2010-2012 at four university hospitals.

PARTICIPANTS

Participants were TIDES subjects (n = 541) for whom genital and phthalate measurements were available and who underwent prenatal serum screening in the first or second trimester.

MAIN OUTCOME MEASURES

Outcomes included hCG levels in maternal serum in the first and second trimesters and anogenital distance (AGD), which is the distance from the anus to the genitals in male and female neonates.

RESULTS

Higher first-trimester urinary mono-n-butyl phthalate (MnBP; P = .01), monobenzyl phthalate (MBzP; P = .03), and mono-carboxy-isooctyl phthalate (P < .01) were associated with higher first-trimester hCG in women carrying female fetuses, and lower hCG in women carrying males. First-trimester hCG was positively correlated with the AGD z score in female neonates, and inversely correlated in males (P = 0.01). We measured significant associations of MnBP (P < .01), MBzP (P = .02), and mono-2-ethylhexyl phthalate (MEHP; P < .01) with AGD, after adjusting for sex differences. Approximately 52% (MnBP) and 25% (MEHP) of this association in males, and 78% in females (MBzP), could be attributed to the phthalate association with hCG.

CONCLUSIONS

First-trimester hCG levels, normalized by fetal sex, may reflect sexually dimorphic action of phthalates on placental function and on genital development.

Fetal sex differences in human chorionic gonadotropin fluctuate by maternal race, age, weight and by gestational age

Circulating levels of the placental glycoprotein hormone human chorionic gonadotropin (hCG) are higher in women carrying female v. male fetuses; yet, the significance of this difference with respect to maternal factors, environmental exposures and neonatal outcomes is unknown. As a first step in evaluating the biologic and clinical significance of sex differences in hCG, we conducted a population-level analysis to assess its stability across subgroups. Subjects were women carrying singleton pregnancies who participated in prenatal and newborn screening programs in CA from 2009 to 2012 (1.1 million serum samples). hCG was measured in the first and second trimesters and fetal sex was determined from the neonatal record. Multivariate linear models were used to estimate hCG means in women carrying female and male fetuses. We report fluctuations in the ratios of female to male hCG by maternal factors and by gestational age. hCG was higher in the case of a female fetus by 11 and 8% in the first and second trimesters, respectively (P<0.0001). There were small (1-5%) fluctuations in the sex difference by maternal race, weight and age. The female-to-male ratio in hCG decreased from 17 to 2% in the first trimester, and then increased from 2 to 19% in the second trimester (P<0.0001). We demonstrate within a well enumerated, diverse US population that the sex difference in hCG overall is stable. Small fluctuations within population subgroups may be relevant to environmental and physiologic effects on the placenta and can be probed further using these types of data.