New Insights into Development of Female Reproductive Tract-Hedgehog-Signal Response in Wolffian Tissues Directly Contributes to Uterus Development.

The reproductive tract in mammals emerges from two ductal systems during embryogenesis: Wolffian ducts (WDs) and Mullerian ducts (MDs). Most of the female reproductive tract (FRT) including the oviducts, uterine horn and cervix, originate from MDs. It is widely accepted that the formation of MDs depends on the preformed WDs within the urogenital primordia. Here, we found that the WD mesenchyme under the regulation of Hedgehog (Hh) signaling is closely related to the developmental processes of the FRT during embryonic and postnatal periods. Deficiency of Sonic hedgehog (Shh), the only Hh ligand expressed exclusively in WDs, prevents the MD mesenchyme from affecting uterine growth along the radial axis. The in vivo cell tracking approach revealed that after WD regression, distinct cells responding to WD-derived Hh signal continue to exist in the developing FRT and gradually contribute to the formation of various tissues such as smooth muscle, endometrial stroma and vascular vessel, in the mouse uterus. Our study thus provides a novel developmental mechanism of FRT relying on WD.

Transcriptional landscape of the embryonic chicken Müllerian duct.

BACKGROUND: Müllerian ducts are paired embryonic tubes that give rise to the female reproductive tract in vertebrates. Many disorders of female reproduction can be attributed to anomalies of Müllerian duct development. However, the molecular genetics of Müllerian duct formation is poorly understood and most disorders of duct development have unknown etiology. In this study, we describe for the first time the transcriptional landscape of the embryonic Müllerian duct, using the chicken embryo as a model system. RNA sequencing was conducted at 1 day intervals during duct formation to identify developmentally-regulated genes, validated by in situ hybridization. RESULTS: This analysis detected hundreds of genes specifically up-regulated during duct morphogenesis. Gene ontology and pathway analysis revealed enrichment for developmental pathways associated with cell adhesion, cell migration and proliferation, ERK and WNT signaling, and, interestingly, axonal guidance. The latter included factors linked to neuronal cell migration or axonal outgrowth, such as Ephrin B2, netrin receptor, SLIT1 and class A semaphorins. A number of transcriptional modules were identified that centred around key hub genes specifying matrix-associated signaling factors; SPOCK1, HTRA3 and ADGRD1. Several novel regulators of the WNT and TFG-ß signaling pathway were identified in Müllerian ducts, including APCDD1 and DKK1, BMP3 and TGFBI. A number of novel transcription factors were also identified, including OSR1, FOXE1, PRICKLE1, TSHZ3 and SMARCA2. In addition, over 100 long non-coding RNAs (lncRNAs) were expressed during duct formation. CONCLUSIONS: This study provides a rich resource of new candidate genes for Müllerian duct development and its disorders. It also sheds light on the molecular pathways engaged during tubulogenesis, a fundamental process in embryonic development.

A suggested bisphenol A metabolite (MBP) interfered with reproductive organ development in the chicken embryo while a human-relevant mixture of phthalate monoesters had no such effects.

Bisphenol A (BPA) and phthalate diesters are ubiquitous environmental contaminants. While these compounds have been reported as reproductive toxicants, their effects may partially be attributed to metabolites. The aim of this study was to examine reproductive organ development in chicken embryos exposed to the BPA metabolite, 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP; 100 µg/g egg) or a human-relevant mixture of 4 phthalate monoesters (85 µg/g egg). The mixture was designed within the EU project EDC-MixRisk based upon a negative association with anogenital distance in boys at 21 months of age in a Swedish pregnancy cohort. Chicken embryos were exposed in ovo from an initial stage of gonad differentiation (embryonic day 4) and dissected two days prior to anticipated hatching (embryonic day 19). No discernible effects were noted on reproductive organs in embryos exposed to the mixture. MBP-treated males exhibited retention of Müllerian ducts and feminization of the left testicle, while MBP-administered females displayed a diminished the left ovary. In the left testicle of MBP-treated males, mRNA expression of female-associated genes was upregulated while the testicular marker gene SOX9 was downregulated, corroborating a feminizing effect by MBP. Our results demonstrate that MBP, but not the phthalate monoester mixture, disrupts both male and female reproductive organ development in an avian embryo model.

Retinoic acid signaling determines the fate of uterine stroma in the mouse Müllerian duct.

The Müllerian duct develops into the oviduct, uterus, and vagina, all of which are quite distinct in their morphology and function. The epithelial fate of these female reproductive organs in developing mice is determined by factors secreted from the stroma; however, how stromal differentiation occurs in the female reproductive organs derived from the Müllerian duct is still unclear. In the present study, roles of retinoic acid (RA) signaling in developing female reproductive tracts were investigated. Retinol dehydrogenase 10 (RDH10) and aldehyde dehydrogenase family 1 subfamily A2 (ALDH1A2) mRNAs and proteins and transactivation activity of endogenous RA were found in the stroma of proximal Müllerian ducts and gradually decreased from the proximal to caudal regions in fetal mice. In organ-cultured Müllerian ducts, retinaldehyde or RA treatment induced uterine epithelial differentiation, defined as a layer of columnar epithelial cells negative for oviductal and vaginal epithelial markers. In contrast, inhibition of RA receptor (RAR) signaling induced vaginal epithelial differentiation, characterized as vaginal epithelial marker genes-positive stratified epithelium. Grafting experiments of the organ-cultured Müllerian duct revealed irreversible epithelial fate determination. Although RAR did not directly bind to the homeobox A10 (Hoxa10) promoter region, RA-RAR signaling stimulated Hoxa10 expression. Thus, RA-RAR signaling in the Müllerian duct determines the fate of stroma to form the future uterus and vagina.

Surgical management of complex atypical endometrial hyperplasia in a woman with rare genitourinary anomalies: unicornuate uterus with rudimentary horn, ipsilateral ectopic ovary and pelvic kidney.

AIM: According to the so far published literature, only one case of endometrial cancer in a patient with unicornuate uterus has been reported. This is a case report study, presenting a rare case of complex atypical endometrial hyperplasia in a woman with unicornuate uterus and multiple genitourinary anomalies. CASE REPORT: A 43-year old G1P1 woman presented with episodes of menometrorrhagia and anemia. She had previous surgical history of laparoscopy due to infertility, in which she was diagnosed with unicornuate uterus with a rudimentary left uterine horn and ipsilateral ectopic ovary in the anatomic place of the left kidney. Dilatation and curettage was performed. Histology showed complex atypical endometrial hyperplasia. The patient underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy, in an extremely interesting operation due to the multiple genitourinary anomalies. The uterus with a 6-centimeter uterine myoma and the adnexae were removed en block. Great effort was put into dissecting the left fallopian tube which arised from the cervix and via the rudimentary horn led to the left ectopic ovary that was located at the left kidneys' anatomic space. The patient recovered well and final histology was negative for malignancy. DISCUSSION: All necessary imaging examinations have to be scheduled prior to surgical intervention in order to give valuable anatomic information in cases of women diagnosed with Mullerian abnormalities.

DMRT1 is required for Müllerian duct formation in the chicken embryo.

DMRT1 is a conserved transcription factor with a central role in gonadal sex differentiation. In all vertebrates studied, DMRT1 plays an essential function in testis development and/or maintenance. No studies have reported a role for DMRT1 outside the gonads. Here, we show that DMRT1 is expressed in the paired Müllerian ducts in the chicken embryo, where it is required for duct formation. DMRT1 mRNA and protein are expressed in the early forming Müllerian ridge, and in cells undergoing an epithelial to mesenchyme transition during duct morphogenesis. RNAi-mediated knockdown of DMRT1 in ovo causes a greatly reduced mesenchymal layer, which blocks caudal extension of the duct luminal epithelium. Critical markers of Müllerian duct formation in mammals, Pax2 in the duct epithelium and Wnt4 in the mesenchyme, are conserved in chicken and their expression disrupted in DMRT1 knockdown ducts. We conclude that DMRT1 is required for the early steps of Müllerian duct development. DMRT1 regulates Müllerian ridge and mesenchyme formation and its loss blocks caudal extension of the duct. While DMRT1 plays an important role during testis development and maintenance in many vertebrate species, this is the first report showing a requirement for DMRT1 in Müllerian duct development.

Genetic analysis of DACT1 in 100 Chinese Han women with Müllerian duct anomalies.

Dapper antagonist of catenin-1 (DACT1) plays an important role in embryogenesis and organogenesis of the female reproductive tract in mouse models. The aim of this study was to investigate the association between DACT1 mutations and human Müllerian duct anomalies (MDA). One hundred clinically well-defined Chinese Han patients with MDA and 200 healthy controls were recruited in this study. All four exons coding for DACT1 were amplified and sequenced. A missense mutation (c.G1084A, p.V362M) was identified in a patient who had a didelphic uterus and was absent from the control group. This variant changed the hydrophilicity of the amino acid residue and was predicted to be deleterious to the structure and function of DACT1 protein. The data indicate that the p.V362M mutation of DACT1 may be an underlying cause of MDA.

HOXA10, EMX2 and TENM1 expression in the mid-secretory endometrium of infertile women with a Müllerian duct anomaly.

Homeobox A10 (HOXA10) and empty spiracles homeobox 2 (EMX2) are two transcription factors necessary for female Müllerian duct differentiation and development. They are thought to play important roles in embryo implantation in mice and humans. The EMX2 gene is a known direct target of HOXA10 in the reproductive tract. Human TENM1 is directly regulated by EMX2 and is expressed during embryonic pattern formation and morphogenesis. This study aimed to investigate expression patterns of HOXA10, EMX2 and TENM1 in the mid-secretory endometrium of infertile patients with a Müllerian duct anomaly causing a partially septate uterus. Thirteen mid-secretory endometrial tissue samples were collected from women with partially septate uteri and 12 from women with normal uteri as controls. Expression levels of HOXA10, EMX2 and TENM1 mRNA and protein in the mid-secretory endometrium of infertile patients and controls were measured by quantitative reverse transcription polymerase chain reaction and western blotting. Compared with controls, mRNA and protein expression levels of HOXA10 decreased significantly (P < 0.01), whereas EMX2 and TENM1 increased dramatically in patients with Müllerian duct anomaly (P < 0.001). Changes in HOXA10, EMX2, and TENM1 expression levels might act in infertile women with Müllerian duct anomaly to cause a partially septate uterus.

Sex-dependent expression of anti-Müllerian hormone (amh) and amh receptor 2 during sex organ differentiation and characterization of the Müllerian duct development in Xenopus tropicalis.

Amphibian gonadal differentiation involves the action of sex steroids. Recent research indicates that the anti-Müllerian hormone (AMH) is involved in testicular development in some lower vertebrate species. For amphibians there is a lack of data on ontogenetic expression of the AMH receptor AMHR2/amhr2 and of progesterone receptors (PGRS/pgrs). Here we expand the knowledge on amphibian sex differentiation by characterizing ontogenetic mRNA levels of amh, amhr2, intracellular and membrane pgrs (ipgr and mpgr beta) and cytochrome P450 19a1 (cyp19a1) (ovarian marker) in the urogenital complex of the model species Xenopus (Silurana) tropicalis. Furthermore, we characterized the ontogenetic development of the Müllerian ducts (precursors of the female reproductive tract) histologically. The developmental period investigated spanned from beginning of gonadal differentiation, Nieuwkoop and Faber (NF) stage 51, to 4weeks post-metamorphosis. The Müllerian ducts were first observed at NF 64 in both sexes. Male-enhanced amh mRNA levels from NF 53/54 to 6days post-metamorphosis and female-enhanced cyp19a1 levels from NF 53 to 4weeks post-metamorphosis were noted. The sexually dimorphic mRNA level profile was more distinct for amh than for cyp19a1. The pgrs mRNA levels increased over the studied period and showed no sex differences. At later developmental stages, the amhr2 mRNA level was increased in putative females compared with males. Our findings suggest that AMH has a role in gonadal differentiation in X. tropicalis. We propose relative gonadal amh mRNA level as a testicular marker during early gonadal development in amphibians.

In ovo treatment with an estrogen receptor alpha selective agonist causes precocious development of the female reproductive tract of the American alligator (Alligator mississippiensis).

The molecular signaling processes involved the differentiation of the Müllerian duct (MD) into the female reproductive tract, or oviduct, in non-mammalian vertebrates are not well understood. Studies in mammals and birds indicate that steroid hormones play a role in this process, as the embryonic MD has been shown to be vulnerable to exogenous estrogens and progestins and environmental endocrine disrupting contaminants. In a previous study, developmental treatment with an estrogen receptor α (ERα) agonist, 4,4',4″-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT), induced significant enlargement of the MD in alligator embryos incubated at a male-producing temperature, which was not observed in embryos treated with an estrogen receptor ß (ERß) agonist, 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY 200070), or with 17ß-estradiol (E2). In order to understand the role of estrogen signaling in female alligator oviduct development, we incubated eggs at a female-producing temperature and treated them with E2 and these ER selective agonists, PPT and WAY 200070, just prior to the thermosensitive window of sex determination. At stage 27, one stage prior to hatching, PPT induced significant enlargement of the MD with precocious development of secretory glands and connective tissue differentiation similar to characteristics of mature adult oviduct. PPT treatment in ovo increased mRNA expression of ERß, progesterone receptor, androgen receptor and insulin-like growth factor 1 in MD at stage 27, while expression of ERα was decreased. Neither WAY 200070 nor E2 treatment induced these effects seen in PPT-treated MD. The results of this study provide insight into the critical factors for healthy reproductive system formation in this sentinel species, although further investigation is needed to determine whether the observed phenomena are directly due to selective stimulation of ERα or related to some other aspect of PPT treatment.

Development of the Larval Amphibian Growth and Development Assay: effects of chronic 4-tert-octylphenol or 17ß-trenbolone exposure in Xenopus laevis from embryo to juvenile.

The Larval Amphibian Growth and Development Assay (LAGDA) is a globally harmonized test guideline developed by the U.S. Environmental Protection Agency in collaboration with Japan's Ministry of the Environment. The LAGDA was designed to evaluate apical effects of chronic chemical exposure on growth, thyroid-mediated amphibian metamorphosis and reproductive development. During the validation phase, two well-characterized endocrine-disrupting chemicals were tested to evaluate the performance of the initial assay design: xenoestrogen 4-tert-octylphenol (tOP) and xenoandrogen 17ß-trenbolone (TB). Xenopus laevis embryos were exposed, in flow-through conditions, to tOP (nominal concentrations: 0.0, 6.25, 12.5, 25 and 50 µg l-1 ) or TB (nominal concentrations: 0.0, 12.5, 25, 50 and 100 ng l-1 ) until 8 weeks post-metamorphosis, at which time growth measurements were taken, and histopathology assessments were made of the gonads, reproductive ducts, liver and kidneys. There were no effects on growth in either study and no signs of overt toxicity, sex reversal or gonad dysgenesis. Exposure to tOP caused a treatment-related decrease in circulating thyroxine and an increase in thyroid follicular cell hypertrophy and hyperplasia (25 and 50 µg l-1 ) during metamorphosis. Müllerian duct development was affected after exposure to both chemicals; tOP exposure caused dose-dependent maturation of oviducts in both male and female frogs, whereas TB exposure caused accelerated Müllerian duct regression in males and complete regression in >50% of the females in the 100 ng l-1 treatment. Based on these results, the LAGDA performed adequately to evaluate apical effects of chronic exposure to two endocrine-active compounds and is the first standardized amphibian multiple life stage toxicity test to date. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Induction of WNT inhibitory factor 1 expression by Müllerian inhibiting substance/antiMullerian hormone in the Müllerian duct mesenchyme is linked to Müllerian duct regression.

A key event during mammalian sexual development is regression of the Müllerian ducts (MDs) in the bipotential urogenital ridges (UGRs) of fetal males, which is caused by the expression of Müllerian inhibiting substance (MIS) in the Sertoli cells of the differentiating testes. The paracrine signaling mechanisms involved in MD regression are not completely understood, particularly since the receptor for MIS, MISR2, is expressed in the mesenchyme surrounding the MD, but regression occurs in both the epithelium and mesenchyme. Microarray analysis comparing MIS signaling competent and Misr2 knockout embryonic UGRs was performed to identify secreted factors that might be important for MIS-mediated regression of the MD. A seven-fold increase in the expression of Wif1, an inhibitor of WNT/ß-catenin signaling, was observed in the Misr2-expressing UGRs. Whole mount in situ hybridization of Wif1 revealed a spatial and temporal pattern of expression consistent with Misr2 during the window of MD regression in the mesenchyme surrounding the MD epithelium that was absent in both female UGRs and UGRs knocked out for Misr2. Knockdown of Wif1 expression in male UGRs by Wif1-specific siRNAs beginning on embryonic day 13.5 resulted in MD retention in an organ culture assay, and exposure of female UGRs to added recombinant human MIS induced Wif1 expression in the MD mesenchyme. Knockdown of Wif1 led to increased expression of ß-catenin and its downstream targets TCF1/LEF1 in the MD mesenchyme and to decreased apoptosis, resulting in partial to complete retention of the MD. These results strongly suggest that WIF1 secretion by the MD mesenchyme plays a role in MD regression in fetal males.

ß-Catenin is essential for Müllerian duct regression during male sexual differentiation.

During male sexual differentiation, the transforming growth factor-ß (TGF-ß) signaling molecule anti-Müllerian hormone (AMH; also known as Müllerian inhibiting substance, MIS) is secreted by the fetal testes and induces regression of the Müllerian ducts, the primordia of the female reproductive tract organs. Currently, the molecular identity of downstream events regulated by the AMH signaling pathway remains unclear. We found that male-specific Wnt4 expression in mouse Müllerian duct mesenchyme depends upon AMH signaling, implicating the WNT pathway as a downstream mediator of Müllerian duct regression. Inactivation of ß-catenin, a mediator of the canonical WNT pathway, did not affect AMH signaling activation in the Müllerian duct mesenchyme, but did block Müllerian duct regression. These data suggest that ß-catenin mediates AMH signaling for Müllerian duct regression during male sexual differentiation.

Spatiotemporal expression patterns of doublesex and mab-3 related transcription factor 1 in the chicken developing gonads and Mullerian ducts.

Sex of birds is genetically determined by the inheritance of sex chromosomes (ZZ for male and ZW for female), and the Z-linked gene named doublesex and mab-3 related transcription factor 1 (DMRT1) is a candidate sex-determining gene in avian species. However, the mechanisms underlying sex determination in birds are not yet understood, and the expression patterns of the DMRT1 protein in urogenital tissues have not been identified. In the current study, we used immunohistochemistry to investigate the detailed expression patterns of the DMRT1 protein in the urogenital systems (including Müllerian ducts) in male and female chicken embryos throughout embryonic development. Gonadal somatic cells in the male indifferent gonads showed stronger expressions of DMRT1 compared with those in the female indifferent gonads well before the presumptive period of the sex determination, and Sertoli cells forming testicular cords expressed DMRT1 in the testes after sex determination. Germ cells expressed DMRT1 equally in males and females after sex determination. The expression was continuous in males, but in females it gradually disappeared from the germ cells in the central part of the cortex of the left ovary toward both edges. The DMRT1 was also detected in the tubal ridge, which is a precursor of the Müllerian duct, and at the mesenchyme and outermost coelomic epithelium of the Müllerian duct in both sexes. Strong expression was observed in the males, but it was restricted to coelomic epithelium after the regression of the duct started. Thus, we observed the detailed spatiotemporal expression patterns of DMRT1 in the developing chicken urogenital systems throughout embryonic development, suggesting its various roles in the development of urogenital tissues in the chicken embryo.

Ethynylestradiol feminizes gene expression partly in testis developing as ovotestis and disrupts asymmetric Müllerian duct development by eliminating asymmetric gene expression in Japanese quail embryos.

In avian embryos, xenoestrogens induce abnormalities in reproductive organs, particularly the testes and Müllerian ducts (MDs). However, the molecular mechanisms remain poorly understood. We investigated the effects of ethynylestradiol (EE2) exposure on gene expression associated with reproductive organ development in Japanese quail embryos. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis revealed that the left testis containing ovary-like tissues following EE2 exposure highly expressed the genes for steroidogenic enzymes (P450scc, P45017α, lyase, and 3ß-HSD) and estrogen receptor-ß, compared to the right testis. No asymmetry was found in these gene expression without EE2. EE2 induced hypertrophy in female MDs and suppressed atrophy in male MDs on both sides. RNA sequencing analysis of female MDs showed 1,366 differentially expressed genes between developing left MD and atrophied right MD in the absence of EE2, and these genes were enriched in Gene Ontology terms related to organogenesis, including cell proliferation, migration and differentiation, and angiogenesis. However, EE2 reduced asymmetrically expressed genes to 21. RT-qPCR analysis indicated that genes promoting cell cycle progression and oncogenesis were more highly expressed in the left MD than in the right MD, but EE2 eliminated such asymmetric gene expression by increasing levels on the right side. EE2-exposed males showed overexpression of these genes in both MDs. This study reveals part of the molecular basis of xenoestrogen-induced abnormalities in avian reproductive organs, where EE2 may partly feminize gene expression in the left testis, developing as the ovotestis, and induce bilateral MD malformation by canceling asymmetric gene expression underlying MD development.

Molecular characteristics and alterations during early development of the human vagina.

Unresolved questions remain concerning the derivation of the vagina with respect to the relative contributions from the Müllerian ducts, the urogenital sinus, and the Wolffian ducts. Recent molecular and cellular studies in rodents have opened up a large gap between the level of understanding of vaginal development in mice and understanding of human vaginal development, which is based on histology. To compare the findings in mice with human vaginal development and to address this gap, we analysed molecular characteristics of the urogenital sinus, Wolffian ducts, and Müllerian ducts in 8-14-week-old human specimens using immunohistochemical methods. The monoclonal antibodies used were directed against cytokeratin (CK) 14, CK19, vimentin, laminin, p63, E-cadherin, caspase-3, Ki67, HOX A13, and BMP-4. The immunohistochemical analysis revealed that, during weeks 8-9, the epithelium of the Müllerian ducts became positive for p63 as p63-positive cells that originated from the sinus epithelium reached the caudal tip of the fused Müllerian ducts via the Wolffian ducts. The lumen of the fused Müllerian ducts was closed by an epithelial plug that contained both vimentin-positive and vimentin-negative cells. Subsequently, the resulting epithelial tube enlarged by proliferation of basal p63-positive cells. The first signs of squamous differentiation were detected during week 14, with the appearance of CK14-positive cells. According to our results, all three components, namely, the urogenital sinus, Wolffian ducts, and Müllerian ducts, interacted during the formation of the human vagina. The sinus epithelium provided p63-positive cells, the Wollfian ducts acted as a 'transporter', and the Müllerian ducts contributed the guiding structure for the vaginal anlagen. Epithelial differentiation began at the end of the period studied and extended in a caudo-cranial direction. The present study is one of the first to provide up-to-date molecular correlates for human vaginal development that can be compared with the results of cell biological studies in rodents.

Normal and abnormal epithelial differentiation in the female reproductive tract.

In mammals, the female reproductive tract (FRT) develops from a pair of paramesonephric or Müllerian ducts (MDs), which arise from coelomic epithelial cells of mesodermal origin. During development, the MDs undergo a dynamic morphogenetic transformation from simple tubes consisting of homogeneous epithelium and surrounding mesenchyme into several distinct organs namely the oviduct, uterus, cervix and vagina. Following the formation of anatomically distinctive organs, the uniform MD epithelium (MDE) differentiates into diverse epithelial cell types with unique morphology and functions in each organ. Classic tissue recombination studies, in which the epithelium and mesenchyme isolated from the newborn mouse FRT were recombined, have established that the organ specific epithelial cell fate of MDE is dictated by the underlying mesenchyme. The tissue recombination studies have also demonstrated that there is a narrow developmental window for the epithelial cell fate determination in MD-derived organs. Accordingly, the developmental plasticity of epithelial cells is mostly lost in mature FRT. If the signaling that controls epithelial differentiation is disrupted at the critical developmental stage, the cell fate of MD-derived epithelial tissues will be permanently altered and can result in epithelial lesions in adult life. A disruption of signaling that maintains epithelial cell fate can also cause epithelial lesions in the FRT. In this review, the pathogenesis of cervical/vaginal adenoses and uterine squamous metaplasia is discussed as examples of such incidences.

[Mayer-Rokitansky-Küster-Hauser syndrome. A report of two cases]. / Síndrome de Mayer-Rokitansky-Küster-Hauser: reporte de dos casos y revisión de la bibliografía.

The Mayer-Rokitansky-Kuster-Hauser is a rare congenital anomaly characterized by lack of vaginal and uterine development variable and normal ovaries. It results from agenesis or hypoplasia Müller duct system. Cervicovaginal agenesis as part of the complex syndrome, is even rarer. We report two cases: adolescent patient with primary amenorrhea, cervicovaginal agenesis and chronic pelvic pain, and a 28-year-old patient with primary amenorrhea, congenital absence of uterus and vagina.

Developmental origin of vaginal epithelium.

The developmental origin of vaginal epithelium has been controversial for nearly a century, with speculation that vaginal epithelium originates from the Müllerian duct, Wolffian duct, and/or urogenital sinus. None of these possibilities have been definitively proven or disproven by direct scientific data. To define precisely the origin of vaginal epithelium, epithelial cells of the Müllerian duct, Wolffian duct, or urogenital sinus were fluorescently labeled in mouse embryos by crossing tdTomato-EGFP dual-reporter transgenic mice with transgenic mouse lines that express Cre-recombinase in each type of epithelium. In embryos and newborn mice, the vagina consisted of fused Müllerian ducts plus the sinus vagina of urogenital sinus origin. However, the proportion of the sinus vagina was significantly reduced as the Müllerian vagina grew caudally. By postpartum day 7, the Müllerian vagina extended to the caudal end of the body, whereas the sinus vagina remained only at the junction between the vagina and perineal skin. As the vagina opened in puberty, urogenital sinus epithelium was detected only in the vulva, but not in the vagina. Additionally, from embryo to adult stages, residual Wolffian duct epithelium was present in the dorsolateral stromal wall of the vagina, but not within vaginal or vulvar epithelium. In conclusion, adult mouse vaginal epithelium is derived solely from Müllerian duct epithelium.

Cell migration and activated PI3K/AKT-directed elongation in the developing rat Müllerian duct.

In vertebrates, the Müllerian duct elongates along the Wolffian duct, a mesonephric structure that is required for Müllerian duct formation. Recently, several genes required for initial Müllerian duct formation have been identified. However, the precise mechanism of Müllerian duct elongation remains to be elucidated. In this study, we investigated dynamic morphological changes in the elongating Müllerian duct in rat urogenital ridges in organ culture manipulated by microincision and/or chemical inhibitors. Mechanical division of the developing Müllerian duct showed that epithelial cells of the Müllerian duct actively migrate along the anterior-posterior axis independent of the proliferative expansion of the anterior portion of the duct. We found that the PI3K/AKT signaling pathway is activated in the Müllerian duct epithelium and is required for elongation of the tip of the duct; however, migration of Müllerian duct epithelial cells proximal to the tip remains intact when PI3K/AKT is inactivated. Although much is known about the molecular and cellular mechanisms leading to Müllerian duct regression, the present findings provide a fuller understanding of the mechanisms contributing to Müllerian duct formation and to the general process of early tubulogenesis.