Timing of androgen receptor disruption and estrogen exposure underlies a spectrum of congenital penile anomalies

Hedgehog Signaling for Urogenital Organogenesis and Prostate Cancer: An Implication for the Epithelial-Mesenchyme Interaction (EMI)

Hedgehog (Hh) signaling is an essential growth factor signaling pathway especially in the regulation of epithelial-mesenchymal interactions (EMI) during the development of the urogenital organs such as the bladder and the external genitalia (EXG). The Hh ligands are often expressed in the epithelia, affecting the surrounding mesenchyme, and thus constituting a form of paracrine signaling. The development of the urogenital organ, therefore, provides an intriguing opportunity to study EMI and its relationship with other pathways, such as hormonal signaling. Cellular interactions of prostate cancer (PCa) with its neighboring tissue is also noteworthy. The local microenvironment, including the bone metastatic site, can release cellular signals which can affect the malignant tumors, and vice versa. Thus, it is necessary to compare possible similarities and divergences in Hh signaling functions and its interaction with other local growth factors, such as BMP (bone morphogenetic protein) between organogenesis and tumorigenesis. Additionally, this review will discuss two pertinent research aspects of Hh signaling: (1) the potential signaling crosstalk between Hh and androgen signaling; and (2) the effect of signaling between the epithelia and the mesenchyme on the status of the basement membrane with extracellular matrix structures located on the epithelial-mesenchymal interface.

In vitro and in vivo endocrine disrupting effects of the azole fungicides triticonazole and flusilazole

Azoles are effective antifungal agents used in both medicine and agriculture. They typically work by inhibiting cytochrome P450 enzymes, primarily CYP51 of the ergosterol biosynthesis pathway, thus damaging the fungal cell membrane. However, apart from their desired antifungal properties, several azoles also exhibit endocrine disrupting properties in mammals, both in vitro and in vivo. Here, we have tested two currently used agricultural azole fungicides, triticonazole and flusilazole, for their in vitro anti-androgenic activity and potential effects on reproductive parameters. Both fungicides showed strong androgen receptor (AR) antagonism and disruption of steroid biosynthesis in vitro. Following gestational exposure to flusilazole (15 or 45 mg/kg bw/day) or triticonazole (150 or 450 mg/kg bw/day) in time-mated Sprague Dawley rats, triticonazole induced shorter male anogenital distance (AGD). Flusilazole exposure did not affect the AGD, but altered fetal male blood hormone profile, with increased androstenedione and decreased estrone levels. Flusilazole and triticonazole have dissimilar effects on reproductive parameters in vivo, but both show endocrine disrupting activities.

Reproductive tract biology: Of mice and men

The study of male and female reproductive tract development requires expertise in two separate disciplines, developmental biology and endocrinology. For ease of experimentation and economy, the mouse has been used extensively as a model for human development and pathogenesis, and for the most part similarities in developmental processes and hormone action provide ample justification for the relevance of mouse models for human reproductive tract development. Indeed, there are many examples describing the phenotype of human genetic disorders that have a reasonably comparable phenotype in mice, attesting to the congruence between mouse and human development. However, anatomic, developmental and endocrinologic differences exist between mice and humans that (1) must be appreciated and (2) considered with caution when extrapolating information between all animal models and humans. It is critical that the investigator be aware of both the similarities and differences in organogenesis and hormone action within male and female reproductive tracts so as to focus on those features of mouse models with clear relevance to human development/pathology. This review, written by a team with extensive expertise in the anatomy, developmental biology and endocrinology of both mouse and human urogenital tracts, focusses upon the significant human/mouse differences, and when appropriate voices a cautionary note regarding extrapolation of mouse models for understanding development of human male and female reproductive tracts.

Differential cell proliferation and cell death during the urethral groove formation in guinea pig model

BACKGROUND

Urethral groove (UG) formation is an important step in penile formation. Because commonly used animal models do not have UG, the mechanisms of UG formation have never been discovered. We aim to discover the cellular mechanism of the UG formation using guinea pig model.

METHODS

Histology was used to study the ontogeny of UG. BrdU immunofluorescence was used to label proliferating cells, cell death was determined using LysoTracker Red and TUNEL staining, and stereology was used for quantification. To reveal Shh mRNA expression patterns, in situ hybridization was performed in guinea pig genital tubercles (GTs) and ShhGFPcre-LacZ-reporter mice were used for comparison.

RESULTS

Cell proliferation in the outer layers and programmed cell death in the inner layers of urethral epithelium played key roles during urethral canal movement from dorsal to ventral aspect and final opening to form UG. Shh mRNA expression domain shifted out to the ventral surface of GT from proximal throughout to distal in guinea pigs, but was excluded from the ventral surface epithelium in midshaft and distal of mouse GT.

CONCLUSION

Differential cell proliferation and cell death in developing urethral epithelium lead to UG formation and Shh expression in ventral surface epithelium of GT may play an important role.

Hormone-responsive genes in the SHH and WNT/β-catenin signaling pathways influence urethral closure and phallus growth

Environmental endocrine disruptors (EEDs) that affect androgen or estrogen activity may disrupt gene regulation during phallus development to cause hypospadias or a masculinized clitoris. We treated developing male tammar wallabies with estrogen and females with androgen from day 20-40 postpartum (pp) during the androgen imprinting window of sensitivity. Estrogen inhibited phallus elongation but had no effect on urethral closure and did not significantly depress testicular androgen synthesis. Androgen treatment in females did not promote phallus elongation but initiated urethral closure. Phalluses were collected for transcriptome sequencing at day 50 pp when they first become sexually dimorphic to examine changes in two signaling pathways, sonic hedgehog (SHH) and wingless-type MMTV integration site family (WNT)/β-catenin. SHH mRNA and β-catenin were predominantly expressed in the urethral epithelium in the tammar phallus, as in eutherian mammals. Estrogen treatment and castration of males induced an upregulation of SHH, while androgen treatment downregulated SHH. These effects appear to be direct since we detected putative estrogen receptor α (ERα) and androgen receptor (AR) binding sites near SHH. WNT5A, like SHH, was downregulated by androgen, while WNT4 was upregulated in female phalluses after androgen treatment. After estrogen treatment, WIF1 and WNT7A were both downregulated in male phalluses. After castration, WNT9A was upregulated. These results suggest that SHH and WNT pathways are regulated by both estrogen and androgen to direct the proliferation and elongation of the phallus during differentiation. Their response to exogenous hormones makes these genes potential targets of EEDs in the etiology of abnormal phallus development including hypospadias.

Regulatory roles of epithelial-mesenchymal interaction (EMI) during early and androgen dependent external genitalia development

Development of external genitalia (ExG) has been a topic of long mystery in the field of organogenesis research. Early stage male and female of mouse embryos develop a common genital tubercle (GT) in the perineum whose outgrowth extends distally from the posterior cloacal regions. Concomitant with GT outgrowth, the cloaca is divided into urogenital sinus and anorectum by urorectal septum (URS) internally. The outgrowth of the GT is associated with the formation of endodermal epithelial urethral plate (UP) attached to the ventral epidermis of the GT. Such a common developmental phase is observed until around embryonic day 15.5 (E15.5) morphologically in mouse embryogenesis. Various growth factor genes, such as Fibroblast growth factor (Fgf) and Wnt genes are expressed and function during GT formation. Since the discovery of key growth factor signals and several regulatory molecules, elucidation of their functions has been achieved utilizing mouse developmental models, conditional gene knockout mouse and in vitro culture. Analyses on the phenotypes of such mouse models have revealed that several growth factor families play fundamental roles in ExG organogenesis based on the epithelial-mesenchymal interaction (EMI). More recently, EMI between developing urethral epithelia and its bilateral mesenchyme of later stages is also reported during subsequent stage of androgen-dependent male-type urethral formation in the mouse embryo. Mafb, belonging to AP-1 family and a key androgen-responsive mesenchymal gene, is identified and starts to be expressed around E14.5 when masculinization of the urethra is initiated. Mesenchymal cell condensation and migration, which are regulated by nonmuscle myosin, are shown to be essential process for masculinization. Hence, studies on EMI at various embryonic stages are important not only for early but also for subsequent masculinization of the urethra. In this review, a dynamic mode of EMI for both early and late phases of ExG development is discussed.

Temporal, spatial, and genetic regulation of external genitalia development

Fertilization requires the physical combination of gametes, and terrestrial mammals necessitated the evolution of genitalia capable of successfully completing the fertilization process in a non-aqueous environment. Thus, the male mammalian external genitalia evolved as an outgrowth from the body, an appendage sufficient to fertilize eggs housed deep inside the female. In this way, sexual dimorphism of mammalian genitalia became highly pronounced. This highly complex evolutionary divergence both from aqueous fertilization, as well as divergence between the sexes of terrestrial mammals, required exquisitely coordinated, novel patterns of gene expression to regulate the spatial and temporal events governing external genitalia development. Recent studies delineating the genetic regulation of external genitalia development, largely focusing on development of the murine genital tubercle, have vastly enlightened the field of reproductive developmental biology. Murine homologs of human genes have been selectively deleted in the mouse, either in the whole body or using tissue-specific and temporally-specific genetic drivers. The defects in outgrowth and urethral tubularization subsequent to the deletion of specific genes in the developing murine external genitalia delineates which genes are required in which compartments and at what times. This review details how these murine genetic models have created a somewhat modest but rapidly growing library of knowledge detailing the spatial-temporal genetic regulation of external genitalia development.

A loss of estrogen signaling in the aromatase deficient mouse penis results in mild hypospadias

Hypospadias is the abnormal opening of the urethra on the underside of the penis and occurs in approximately 1/125 live male births worldwide. The incidence rate of hypospadias has dramatically increased over the past few decades. This is now attributed, at least in part, to our exposure to endocrine-disrupting chemicals (EDCs) which alter the hormonal signals required for development of the penis. In humans androgens are the main drivers of fusion of the urethral folds to form the urethra within the shaft of the penis, a process required for termination of the urethra in its normal location at the tip of the penis. However, recent research has suggested that estrogen also plays a role in this process. To better understand how EDCs impact urethral development it is essential that we understand the normal function of hormones during development of the penis. To define the role of estrogen in urethral development we examined development of the penis in the aromatase (Cyp19a1) Knockout (ArKO) mouse strain in which endogenous estrogen production is completely ablated. We found that the ArKO penis had a mild hypospadias phenotype. The developing ArKO postnatal penis displayed an early disruption in preputial development, which likely causes the mild hypospadias observed in adults. Using qPCR, we found altered expression of keratin genes and key urethral patterning genes in response to the disrupted estrogen signaling. The hypospadias phenotype was almost identical to that reported for the estrogen receptor α (ERα) knockout confirming that ERα is the predominant receptor for mediating estrogen action during development of the mouse penis. Our results show that estrogen is required for normal prepucial development and placement of the mature urethral opening at the distal aspect of the penis. We also identified several genes which are potential downstream targets of estrogen during normal urethral closure. With this knowledge, we can now better understand how anti-estrogenic as well as estrogenic EDCs disrupt urethral closure to cause mild hypospadias in both mice and humans.

A critical role for estrogen signaling in penis development

Hypospadias, a developmental defect of the penis, is one of the most common congenital malformations in humans. Its incidence has rapidly increased over recent decades, and this has been largely attributed to our increased exposure to endocrine-disrupting chemicals. Penis development is primarily an androgen-driven process; however, estrogen and xenoestrogens are known to affect penis development in both humans and mice. Here, we investigated the role of estrogen in the developing penis. Using a novel penis culture system, we showed that exogenous estrogen directly targets the developing penis in utero to cause hypospadias. In addition, we also uncovered an unexpected endogenous role for estrogen in normal postnatal penis development and showed that a loss of estrogen signaling results in a mild hypospadias phenotype, the most common manifestation of this disease in humans. Our findings demonstrated that both androgen and estrogen signaling are intrinsically required for normal urethral closure. These findings confirmed that penis development is not an entirely androgen-driven process but one in which endogenous estrogen signaling also plays a critical role.-Govers, L. C., Phillips, T. R., Mattiske, D. M., Rashoo, N., Black, J. R., Sinclair, A., Baskin, L. S., Risbridger, G. P., Pask, A. J. A critical role for estrogen signaling in penis development.

Prenatal masculinization of the auditory system in infants: The MIREC-ID study

Sex differences in inner-ear function are detectable in infants, notably through the measurement of otoacoustic emissions (OAEs). Prevailing theories posit that prenatal exposure to high levels of androgens in boys may weaken OAEs, and that this phenomenon may predominantly affect the right ear/left hemisphere (Geschwind-Galaburda (GG) hypothesis). Yet, actual tests of these models have been difficult to implement in humans. Here we examined the relationship between markers of fetal androgen exposure collected at birth (anogenital distances (AGD); penile length/width, areolar/scrotal/vulvar pigmentation) and at 6 months of age (2^nd to 4^th digit ratio (2D:4D)) with two types of OAEs, click-evoked OAEs (CEOAEs) and distortion-product OAEs (DPOAEs) (n = 49; 25 boys; 24 girls). We found that, in boys, scrotal pigmentation was inversely associated with the amplitude and reproducibility of CEOAEs in the right ear at 4 kHz, with trends also present in the same ear for mean CEOAE amplitude and CEOAE amplitude at 2 kHz. Penile length was inversely associated with the mean amplitude of DPOAEs in both the right and left ears, as well as with DPOAE amplitude in the right ear at 2 kHz and the reproducibility of CEOAEs in the left ear at 2.8 kHz. Finally, AGD-scrotum in boys was positively associated in boys with the amplitude of DPOAEs in the left ear at 2.8 kHz. Unexpectedly, there were no sex differences in the amplitude or reproducibility of OAEs, nor, in girls, any associations between androgenic markers and auditory function. Nonetheless, these findings, reported for the first time in a sample of human infants, support both the prenatal-androgen-exposure and GG models as explanations for the masculinization of auditory function in male infants.

Developmental mutant mouse models for external genitalia formation

Development of external genitalia and perineum is the subject of developmental biology as well as toxicology and teratology researches. Cloaca forms in the lower (caudal) end of endoderm. Such endodermal epithelia and surrounding mesenchyme interact with various signals to form the external genitalia. External genitalia (the anlage termed as genital tubercle: GT) formation shows prominent sexually dimorphic morphogenesis in late embryonic stages, which is an unexplored developmental research field because of many reasons. External genitalia develop adjacent to the cloaca which develops urethra and corporal bodies. Developmental regulators including growth factor signals are necessary for epithelia-mesenchyme interaction (EMI) in posterior embryos including the cloaca and urethra in the genitalia. In the case of male type urethra, formation of tubular urethra proceeds from the lower (ventral) side of external genitalia as a masculinization process in contrast to the case of female urethra. Mechanisms for its development are not elucidated yet due to the lack of suitable mutant mouse models. Because of the recent progresses of Cre (recombinase)-mediated conditional target gene modification analyses, many developmental regulatory genes become increasingly analyzed. Conditional gene knockout mouse approaches and tissue lineage approaches are expected to offer vital information for such sexually dimorphic developmental processes. This review aims to offer recent updates on the progresses of these emerging developmental processes for the research field of congenital anomalies.

Dihydrotestosterone induces minor transcriptional alterations in genital skin fibroblasts of children with and without androgen insensitivity

Endogenous and exogenous androgens induce masculinization of external genitalia through binding to the androgen receptor (AR). The target genes of androgens in external genitalia remain to be determined, although previous studies have shown that the apolipoprotein D gene (APOD) was significantly upregulated by dihydrotestosterone (DHT), the most potent androgen in humans. In the present study, we performed microarray analysis for genital skin fibroblasts obtained from four boys with buried penis (the control individuals) and a patient with partial androgen insensitivity syndrome (PAIS) due to a hypomorphic mutation in AR (the PAIS patient). We identified 24 transcripts that were upregulated or downregulated by DHT in all samples of control individuals and, to a lesser extent, in the sample of the PAIS patient. Differences between DHT-treated and -untreated samples were small; the results of 24 transcripts did not reach statistical significance. The 24 transcripts included CYP1B1, a gene possibly involved in the development of genital tubercle in mice, and APOD, as well as several genes that have been reported as androgen targets in prostate or other tissues. The results of this study indicate that androgen-mediated masculinization of external genitalia is unlikely to depend on massive transcriptional changes in specific AR target genes. Rather, minor transcriptional changes of several genes, and/or a complex molecular network may play a major role in penile development. Importantly, our data suggest the possible involvement of CYP1B1 in human genital development and confirm the clinical importance of APOD as a biomarker for AR function.

Androgen and Oestrogen Affect the Expression of Long Non-Coding RNAs During Phallus Development in a Marsupial

There is increasing evidence that long non-coding RNAs (lncRNAs) are important for normal reproductive development, yet very few lncRNAs have been identified in phalluses so far. Unlike eutherians, phallus development in the marsupial tammar wallaby occurs post-natally, enabling manipulation not possible in eutherians in which differentiation occurs in utero. We treated with sex steroids to determine the effects of androgen and oestrogen on lncRNA expression during phallus development. Hormonal manipulations altered the coding and non-coding gene expression profile of phalluses. We identified several predicted co-regulatory lncRNAs that appear to be co-expressed with the hormone-responsive candidate genes regulating urethral closure and phallus growth, namely IGF1, AR and ESR1. Interestingly, more than 50% of AR-associated coding genes and lncRNAs were also associated with ESR1. In addition, we identified and validated three novel co-regulatory and hormone-responsive lncRNAs: lnc-BMP5, lnc-ZBTB16 and lncRSPO4. Lnc-BMP5 was detected in the urethral epithelium of male phalluses and was downregulated by oestrogen in males. Lnc-ZBTB16 was downregulated by oestrogen treatment in male phalluses at day 50 post-partum (pp). LncRSPO4 was downregulated by adiol treatment in female phalluses but increased in male phalluses after castration. Thus, the expression pattern and hormone responsiveness of these lncRNAs suggests a physiological role in the development of the phallus.

Functional distinctions associated with the diversity of sex steroid hormone receptors ESR and AR

Sex steroid hormones including estrogens and androgens play fundamental roles in regulating reproductive activities and they act through estrogen and androgen receptors (ESR and AR). These steroid receptors have evolved from a common ancestor in association with several gene duplications. In most vertebrates, this has resulted in two ESR subtypes (ESR1 and ESR2) and one AR, whereas in teleost fish there are at least three ESRs (ESR1, ESR2a and ESR2b) and two ARs (ARα and ARβ) due to a lineage-specific whole genome duplication. Functional distinctions have been suggested among these receptors, but to date their roles have only been characterized in a limited number of species. Sexual differentiation and the development of reproductive organs are indispensable for all animal species and in vertebrates these events depend on the action of sex steroid hormones. Here we review the recent progress in understanding of the functions of the ESRs and ARs in the development and expression of sexually dimorphic characteristics associated with steroid hormone signaling in vertebrates, with representative fish, amphibians, reptiles, birds and mammals.

Molecular genetics of hypospadias and cryptorchidism recent developments

During the last decade, a tremendous amount of work has been devoted to the study of the molecular genetics of isolated hypospadias and cryptorchidism, two minor forms of disorders of sex development (DSD). Beyond the genes involved in gonadal determination and sex differentiation, including those underlying androgen biosynthesis and signaling, new genes have been identified through genome-wide association study and familial clustering. Even if no single genetic defect can explain the whole spectrum of DSD, these recent studies reinforce the strong role of the genetic background in the occurrence of these defects. The timing of signaling disruption may explain the different phenotypes.

Immunohistochemical expression analysis of the human fetal lower urogenital tract

We have studied the ontogeny of the developing human male and female urogenital tracts from 9 weeks (indifferent stage) to 16 weeks (advanced sex differentiation) of gestation by immunohistochemistry on mid-sagittal sections. Sixteen human fetal pelvises were serial sectioned in the sagittal plane and stained with antibodies to epithelial, muscle, nerve, proliferation and hormone receptor markers. Key findings are: (1) The corpus cavernosum in males and females extends into the glans penis and clitoris, respectively, during the ambisexual stage (9 weeks) and thus appears to be an androgen-independent event. (2) The entire human male (and female) urethra is endodermal in origin based on the presence of FOXA1, KRT 7, uroplakin, and the absence of KRT10 staining. The endoderm of the urethra interfaces with ectodermal epidermis at the site of the urethral meatus. (3) The surface epithelium of the verumontanum is endodermal in origin (FOXA1-positive) with a possible contribution of Pax2-positive epithelial cells implying additional input from the Wolffian duct epithelium. (4) Prostatic ducts arise from the endodermal (FOXA1-positive) urogenital sinus epithelium near the verumontanum. (5) Immunohistochemical staining of mid-sagittal and para-sagittal sections revealed the external anal sphincter, levator ani, bulbospongiosus muscle and the anatomic relationships between these developing skeletal muscles and organs of the male and female reproductive tracts. Future studies of normal human developmental anatomy will lay the foundation for understanding congenital anomalies of the lower urogenital tract.

External Genital Development, Urethra Formation, and Hypospadias Induction in Guinea Pig: A Double Zipper Model for Human Urethral Development

OBJECTIVE

To determine whether the guinea pig phallus would be an appropriate model of human penile development, we characterized the embryology and sexual differentiation of guinea pig external genitalia and attended to induce hypospadias in males and tubular urethra formation in females pharmacologically.

MATERIALS AND METHODS

The external genitalia of guinea pig were collected from genital swelling initiation to newborn stages, and scanning electronic microscopy and histology were performed to visualize the morphology and structure. Immunohistochemistry was used to determine the androgen receptor localization. Bicalutamide and methyltestosterone were given to pregnant dams to reveal the role and timing of androgen in guinea pig penile masculinization.

RESULTS

Canalization and dorsal-to-ventral movement of the urethral canal develops the urethral groove in both sexes, and then the males perform distal-opening-proximal-closing to form tubular urethra. More nuclear-localized androgen receptor is found in proximal genital tubercles of males than in females at (E) 29. Antiandrogen treatment at E26-E30 can cause hypospadias, and methyltestosterone administration at E27-E31 can induce tubular urethra formation in females.

CONCLUSION

Fetal development of the guinea pig phallus is homologous to that of humans. Although guinea pig has structures similar to mouse, the urethral groove and the tubular urethra formation are more similar to humans. Antiandrogen treatment causes hypospadias in males and additional androgen induces tubular urethra formation in females. Thus, guinea pig is an appropriate model for further study of cellular and molecular mechanisms involved in distal-opening-proximal-closing in tubular urethra formation and the evaluation of the pathophysiological processes of hypospadias.

Renal Subcapsular xenografing of human fetal external genital tissue - A new model for investigating urethral development

In this paper, we introduce our novel renal subcapsular xenograft model for the study of human penile urethral and clitoral development. We grafted fifteen intact fetal penes and clitorides 8-11 weeks fetal age under the renal capsules of gonadectomized athymic mice. The mice were treated with a subcutaneous pellet of dihydrotestosterone (DHT), diethylstilbestrol (DES) or untreated with hormones. Xenografts were harvested after fourteen days of growth and analyzed via serial histologic sectioning and immunostaining for Ki-67, cytokeratins 6, 7 and 10, uroplakin and the androgen receptor. Non-grafted specimens of similar fetal age were sectioned and immunostained for the same antigenic markers. 14/15 (93.3%) grafts were successfully propagated and harvested. The developing urethral plate, urethral groove, tubular urethra, corporal bodies and preputial lamina were easily identifiable. These structures demonstrated robust cellularity, appropriate architecture and abundant Ki-67 expression. Expression patterns of cytokeratins 6, 7 and 10, uroplakin and the androgen receptor in xenografted specimens demonstrated characteristic male/female differences analogous to non-grafted specimens. DHT treatment reliably produced tubularization of nascent urethral and vestibular structures and male patterns of androgen receptor expression in grafts of both genetic sexes while estrogenic or hormonally absent conditions reliably resulted in a persistent open urethral/vestibular groove and female patterns of androgen receptor expression. This model's success enables further study into causal pathways by which endocrine-disrupting and endocrine-mimicking substances may directly cause disruption of normal human urethral development or hypospadias.

Impact of phthalate and BPA exposure during in utero windows of susceptibility on reproductive hormones and sexual maturation in peripubertal males

BACKGROUND

Phthalates and BPA are endocrine disrupting chemicals (EDCs) widely used in consumer products. Evidence suggests that phthalate and BPA exposure alters steroid hormone levels in adults, while in utero exposure has been associated with altered fetal reproductive development in boys. However, the impact of exposure during distinct critical windows of in utero development on hormone concentrations and sexual maturation during the pubertal transition has not been examined. The objective of this study was to assess trimester-specific in utero phthalate and BPA exposure in relation to measures of reproductive development among peripubertal boys in a Mexico City birth cohort.

METHODS

We measured maternal urinary phthalate metabolites and BPA during the first, second, and third trimesters of pregnancy. We measured serum levels of testosterone, estradiol, dehydroepiandrosterone sulfate (DHEA-S), inhibin B, and sex hormone-binding globulin (SHBG), and assessed sexual maturation (Tanner staging and testicular volume) among male children at age 8-14 years (n = 109). Linear and logistic regression were used to investigate trimester-specific in utero exposure as predictors of peripubertal hormone levels and sexual maturation, respectively. In sensitivity analyses we evaluated estimated exposure at 7 weeks gestation and rates of change in exposure across pregnancy in relation to outcomes.

RESULTS

Exposure to phthalates during the third trimester was associated with reduced odds of having a Tanner stage >1 for pubic hair development (e.g. MBzP OR = 0.18 per interquartile range (IQR) increase; 95% CI:0.03-0.97) and higher peripubertal SHBG levels (e.g. MBzP 15.2%/IQR; 95% CI:3.2-28%), while first and second trimester phthalates were not. In contrast, exposure to DEHP during the first trimester was associated with higher estradiol (11%/IQR; 95% CI:1.5-22%), while second or third trimester DEHP exposure was not. Sensitivity analyses yielded similar findings.

CONCLUSIONS

Associations between in utero phthalate and BPA exposure and peripubertal measures of male reproductive development are dependent on the timing of that exposure during gestation. These findings suggest that future epidemiological studies relating in utero EDC exposure to pubertal outcomes should consider windows of susceptibility.

Frozen-thawed blastocyst transfer in natural cycle: feasibility in everyday clinical practice

PURPOSE

Transfer of frozen-thawed embryos in natural cycle is gaining consensus but evidence on this approach is scanty. The aim of this study is reporting on the feasibility of this type of policy in everyday clinical practice.

METHODS

We retrospectively selected all women undergoing the procedure between July 2013 and December 2014. During the study period, women were systematically scheduled for natural cycle if they referred regular menstrual cycles. Hormone replacement therapy (HRT) was conversely prescribed if the woman had irregular menstrual cycles or if the monitoring of the natural cycle failed. The analysis exclusively focussed on the first cycle per woman.

RESULTS

Overall, 251 women were selected. HRT was initially chosen in 52 women, leaving 199 women suitable for the natural cycle. This procedure could be performed in 194 of these women (97%, 95% CI 95-99%). Two additional women initially allocated to HRT ultimately performed the blastocyst transfer with natural cycle. Overall, 196 were thus treated with natural cycle (78%, 95% CI 73-83%). The basal characteristics of the women who did and did not undergo natural cycles were similar with the exceptions of serum FSH (p < 0.001) and AMH (p = 0.03). The live birth rate did not also differ (34% versus 31%, p = 0.63). Characteristics of women treated with the natural cycle who did (n = 67) and did not (n = 129) achieve a live birth did not differ.

CONCLUSION

Frozen-thawed blastocyst transfer in natural cycle can be successfully performed in the vast majority of women.

Penile Allotransplantation for Complex Genitourinary Reconstruction

PURPOSE

Reconstruction of complex functional structures is increasingly being performed with vascularized composite allotransplantation. Penile transplantation is a novel vascularized composite allotransplantation treatment option for severe penile tissue loss and disfigurement. Three allogeneic human penile transplantations have been reported. We review these cases as well as penile transplant indications, preclinical models and immunosuppression therapy.

MATERIALS AND METHODS

We performed a comprehensive literature review for the years 1970 to 2016 via MEDLINE®, PubMed® and Google with the key words "penis transplantation," "penile rejection," "penile replantation," "penile tissue loss" and "penis vascularized composite allotransplantation." Relevant articles, including original research, reviews and nonscientific press reports, were selected based on contents, and a review of this literature was generated.

RESULTS

Three human allogeneic penile transplantations have been performed to date, of which 1 was removed 14 days after transplantation. The second recipient reports natural spontaneous erections and impregnating his partner. All 3 patients were able to void spontaneously through the graft's urethra. The complexity of the transplant is determined by how proximally the penile shaft anastomosis is performed and additional pelvic tissue may be transplanted en bloc if needed.

CONCLUSIONS

Penile transplantation is a technically demanding procedure with significant ethical and psychosocial implications that can provide tissue and functional replacement, including urinary diversion and natural erections. It is unclear how rejection and immunosuppression may affect graft function. Better models and more preclinical research are needed to better understand and optimize penile transplantation.

Dose Dependent Dual Effect of Baicalin and Herb Huang Qin Extract on Angiogenesis

Huang Qin (root of Scutellaria baicalensis) is a widely used herb in different countries for adjuvant therapy of inflammation, diabetes, hypertension, different kinds of cancer and virus related diseases. Baicalin is the main flavonoid in this herb and has been extensively studied for 30 years. The angiogenic effect of herb Huang Qin extract and baicalin was found 13 years ago, however, the results were controversial with pro-angiogenic effect in some studies and anti-angiogenic effect in others. In this paper, the angiogenic effect of baicalin, its aglycone form baicalein and aqueous extract of Huang Qin was studied in chick embryo chorioallantoic membrane (CAM) model. Dose dependent dual effect was found in both aqueous extract and baicalin, but not in baicalein, in which only inhibitory effect was observed. In order to reveal the cellular and molecular mechanism of how baicalin and baicalein affect angiogenesis, cell proliferation and programmed cell death assays were performed in treated CAM. In addition, quantitative PCR array including 84 angiogenesis related genes was used to detect high and low dosage of baicalin and baicalein responsive genes. Low dose baicalin increased cell proliferation in developing blood vessels through upregulation of multiple angiogenic genes expression, but high dose baicalin induced cell death, performing inhibitory effect on angiogenesis. Both high and low dose of baicalein down regulated the expression of multiple angiogenic genes, decreased cell proliferation, and leads to inhibitory effects on angiogenesis.

Ancestral androgenic differentiation pathways are repurposed during the evolution of adult sexual plasticity

Although early exposure to androgens is necessary to permanently organize male phenotype in many vertebrates, animals that exhibit adult sexual plasticity require mechanisms that prevent early fixation of genital morphology and allow for genital morphogenesis during adult transformation. In Lythrypnus dalli, a teleost fish that exhibits bi-directional sex change, adults display dimorphic genitalia morphology despite the absence of sex differences in the potent fish androgen 11-ketotestosterone. Based on conserved patterns of vertebrate development, two steroid-based mechanisms may regulate the early development and adult maintenance of dimorphic genitalia; local androgen receptor (AR) and steroidogenic enzyme expression. Consistent with the ancestral pattern of AR expression during the multipotential phase of differentiation, juvenile differentiation into either sex involved high mesenchymal AR expression. In adults, AR expression was high throughout the male genitalia, but low or absent in females. Consistent with the hypothesis that adult sexual plasticity repurposes pathways from primary differentiation, we show that adults with transitioning genitalia also exhibited higher AR expression relative to females. Local androgen biosynthesis may also participate in genitalia transformation, as transitioning adults had greater 11β-HSD-like immunoreactivity in the epithelial layer of the dorsal lumen compared to both sexes. By administering an AR antagonist to adult males, we show AR is necessary to maintain male-typical morphology. In a species that is resistant to early sexual canalization, early androgenic differentiation mechanisms are consistent with other vertebrates and the tissue-specific regulation of AR expression appears to be repurposed in adulthood to allow for transitions between sexual phenotypes.

Spatiotemporal dynamics of androgen signaling underlie sexual differentiation and congenital malformations of the urethra and vagina

Disorders of sex development (DSDs) are congenital anomalies that affect sexual differentiation of genitourinary organs and secondary sex characters. A common cause of female genital virilization is congenital adrenal hyperplasia (CAH), in which excess androgen production during development of 46XX females can result in vaginal atresia, masculinization of the urethra, a single urogenital sinus, and clitoral hypertrophy or ambiguous external genitalia. Development of the vagina depends on sexual differentiation of the urogenital sinus ridge, an epithelial thickening that forms where the sex ducts attach to the anterior urethra. In females, the sinus ridge descends posteriorly to allow the vaginal opening to form in the vulva, whereas in males and in females with CAH, androgens inhibit descent of the sinus ridge. The mechanisms that regulate development of the female urethra and vagina are largely unknown. Here we show that the timing and duration of, and the cell population targeted by, androgen signaling determine the position of vaginal attachment to the urethra. Manipulations of androgen signaling in utero reveal a temporal window of development when sinus ridge fate is determined. Cell type-specific genetic deletions of androgen receptor (Ar) identify a subpopulation of mesenchymal cells that regulate sinus ridge morphogenesis. These results reveal a common mechanism that coordinates development of the vagina and feminization of the urethra, which may account for development of a single urogenital sinus in females exposed to excessive androgen during a critical period of prenatal development.

Epispadias and the associated embryopathies: genetic and developmental basis

The abnormalities in the urogenital organs are frequently observed as human developmental diseases. Among such diseases, the defects in the upper part of external genitalia are rather rare named epispadias. The cleft in the dorsal part of external genitalia often reaches to the urethra. In general, the urogenital abnormalities accompany defects in the adjacent tissues and organs. The ventral body wall and bladder can also be affected in the patients with dorsal defects of the external genitalia. Therefore, such multiple malformations are often classified as bladder exstrophy and epispadias complex (BEEC). Because of the lower frequency of such birth defects and their early embryonic development, animal models are required to analyze the pathogenic mechanisms and the functions of responsible genes. Mutant mouse analyses on various signal cascades for external genitalia and body wall development are increasingly performed. The genetic interactions between growth factors such as bone morphogenetic proteins (Bmp) and transcription factors such as Msx1/2 and Isl1 have been suggested to play roles for such organogenesis. The significance of epithelial-mesenchymal interaction (EMI) is suggested during development. In this review, we describe on such local interactions and developmental regulators. We also introduce some mutant mouse models displaying external genitalia-body wall abnormalities.

Tetraploid/Diploid Mosaicism in Cultured Genital Skin Fibroblasts: Is It Causally Related to Penoscrotal Hypospadias?

Tetraploid/diploid mosaicism is a rare chromosomal abnormality that is infrequently reported in patients with severe developmental delay, growth retardation, and short life span. Here, we present a 6-year-old patient with severe penoscrotal hypospadias and a coloboma of the left eye but with normal growth, normal psychomotor development, and without dysmorphisms. We considered a local, mosaic sex chromosomal aneuploidy as a possible cause of his genital anomaly and performed karyotyping in cultured fibroblasts from the genital skin, obtained during surgical correction. Tetraploid/diploid (92,XXYY/46,XY) mosaicism was found in 43/57 and 6/26 metaphases in 2 separate cultures, respectively. Buccal smear cells, blood lymphocytes, and cells from urine sediment all showed diploidy. We investigated whether this chromosomal abnormality could be found in other patients with severe hypospadias and karyotyped genital fibroblasts of 6 additional patients but found only low frequencies (<11%) of tetraploid cells, not statistically different from those found in control males with no hypospadias. This is the first time tetraploid mosaicism is found in such a high percentage in a patient without psychomotor retardation, dysmorphisms or growth delay. Although the relationship between this observed mosaicism in cultured cells and the underlying pathogenetic mechanism in penoscrotal hypospadias remains to be determined, our data clearly illustrate the power of cytogenetic techniques in detecting mosaicism compared to next-generation sequencing techniques, in which DNA pooled from multiple cells is used.

Molecular Characterization of the Genital Organizer: Gene Expression Profile of the Mouse Urethral Plate Epithelium

PURPOSE

Lower urinary tract malformations are among the most common congenital anomalies in humans. Molecular genetic studies of mouse external genital development have begun to identify mechanisms that pattern the genital tubercle and orchestrate urethral tubulogenesis. The urethral plate epithelium is an endodermal signaling region that has an essential role in external genital development. However, little is known about the molecular identity of this cell population or the genes that regulate its activity.

MATERIALS AND METHODS

We used microarray analysis to characterize differences in gene expression between urethral plate epithelium and surrounding tissue in mouse genital tubercles. In situ hybridizations were performed to map gene expression patterns and ToppCluster (https://toppcluster.cchmc.org/) was used to analyze gene associations.

RESULTS

A total of 84 genes were enriched at least 20-fold in urethral plate epithelium relative to surrounding tissue. The majority of these genes were expressed throughout the urethral plate in males and females at embryonic day 12.5 when the urethral plate is known to signal. Functional analysis using ToppCluster revealed genetic pathways with known functions in other organ systems but unknown roles in external genital development. Additionally, a 3-dimensional molecular atlas of genes enriched in urethral plate epithelium was generated and deposited at the GUDMAP (GenitoUrinary Development Molecular Anatomy Project) website (http://gudmap.org/).

CONCLUSIONS

We identified dozens of genes previously unknown to be expressed in urethral plate epithelium at a crucial developmental period. It provides a novel panel of genes for analysis in animal models and in humans with external genital anomalies.