Generation of epithelial-stromal assembloids as an advanced in vitro model of impaired adenomyosis-related endometrial receptivity

OBJECTIVE

To create a novel, more advanced in vitro model of human endometrium, using so-called assembloids, looking to explore endometrial receptivity in adenomyosis.

DESIGN

Evaluation of assembloid responsiveness to hormonal stimulation by immunohistochemistry, enzyme-linked immunosorbent assay, and scanning electron microscopy.

SETTING

University-based research unit in gynecology.

PATIENT(S)

Twelve women, six of whom were affected by adenomyosis.

INTERVENTION(S)

Organoids (in the form of glandular fragments) and stromal fibroblasts were collected from endometrial biopsies. The two populations were combined inside an extracellular matrix to create 3D assembloids, which were then exposed to hormonal stimulation (β-estradiol for 48 hours, followed by β-estradiol/progesterone/cyclic adenosine monophosphate for 72 hours) to mimic the window of implantation.

MAIN OUTCOME MEASURE(S)

Glycodelin, leukemia inhibitory factor (LIF), and homeobox A10 (HOXA10) expression, prolactin secretion, and pinopode development.

RESULT(S)

Endometrial organoids and stromal cells were successfully isolated from women with and without adenomyosis and combined to generate the assembloid model. On stimulation, assembloids from both groups acquired a more secretory phase-like phenotype, as demonstrated by histology, and were shown to be positive for glycodelin, LIF, and HOXA10 by immunohistochemistry. Adenomyotic assembloids expressed significantly lower levels of LIF and HOXA10 within the stromal compartment after stimulation than did healthy assembloids in the same condition. Enzyme-linked immunosorbent assay revealed prolactin secretion in vitro, showing an upward trend in hormonally treated assembloids from both healthy and affected women. By scanning electron microscopy, fully formed pinopodes were discerned on the epithelial surface of healthy assembloids after stimulation, but they were absent in case of adenomyosis.

CONCLUSION(S)

Primary assembloids can be generated from endometrial biopsies from both healthy subjects and women affected by adenomyosis. These assembloids are amenable to hormonal stimulation and mimic secretory phase-specific characteristics of endometrial tissue in vivo, including glycodelin, LIF, and HOXA10 expression, and pinopode formation. Assembloids from adenomyosis appear to be less sensitive to hormonal treatment, showing reduced expression of LIF and HOXA10 in the stromal compartment and failing to form pinopodes. All in all, endometrial assembloids may serve as an advanced preclinical model of adenomyosis-related impaired endometrial receptivity, opening up new horizons in understanding and treating the condition.

Spatiotemporal Mapping and Molecular Basis of Whole-brain Circuit Maturation

Brain development is highly dynamic and asynchronous, marked by the sequential maturation of functional circuits across the brain. The timing and mechanisms driving circuit maturation remain elusive due to an inability to identify and map maturing neuronal populations. Here we create DevATLAS (Developmental Activation Timing-based Longitudinal Acquisition System) to overcome this obstacle. We develop whole-brain mapping methods to construct the first longitudinal, spatiotemporal map of circuit maturation in early postnatal mouse brains. Moreover, we uncover dramatic impairments within the deep cortical layers in a neurodevelopmental disorders (NDDs) model, demonstrating the utility of this resource to pinpoint when and where circuit maturation is disrupted. Using DevATLAS, we reveal that early experiences accelerate the development of hippocampus-dependent learning by increasing the synaptically mature granule cell population in the dentate gyrus. Finally, DevATLAS enables the discovery of molecular mechanisms driving activity-dependent circuit maturation.

Uterine Anteroposterior Diameter Measured by Transvaginal Sonography is a Predictor for Dysmenorrhea in Patients With and Without Endometriosis: A Pilot Study

PURPOSE

The aim of this study was to determine the correlation between uterine diameters and menstrual abdominal pain intensity in patients with and without endometriosis (EM), and the independent influence of EM on the pain intensity.

METHODS

Uterine diameters and the diagnosis of adenomyosis were ascertained by transvaginal ultrasonography (TVS). Menstrual abdominal pain intensity was estimated by visual analog scale (VAS). Linear regression was used to figure out the impact of uterine diameters and EM on the VAS scores. Logistic regression was used to calculate the correlation between uterine diameters and the diagnosis of adenomyosis. The cutoff values of uterine anteroposterior diameter (AD) to predict dysmenorrhea (VAS ≥ 4) and the diagnosis of adenomyosis were determined by receiver operating characteristic curves.

RESULTS

There were 220 patients with and 233 patients without EM included. Uterine AD independently correlated with the VAS scores in patients with (B = .230, P = .000) and without (B = .203, P = .000) EM. A uterine AD of 39.5 mm predicted dysmenorrhea in both groups. The presence of EM increased the VAS scores by 1.151 points when controlling for uterine diameters. Uterine AD also independently correlated with the diagnosis of adenomyosis under TVS in patients with (OR = 1.212, 95% CI = 1.130-1.301; P = .000) and without (OR = 1.192, 95% CI = 1.123-1.263; P = .000) EM. A uterine AD of 38.5 and 39.5 mm predicted the diagnosis of adenomyosis under TVS in patients with and without EM, respectively.

CONCLUSIONS

Increased uterine AD, which is probably ascribed to adenomyosis, plays an important role in augmented menstrual abdominal pain intensity. Meanwhile, the presence of EM reinforces the pain.

Unveiling the Pathogenesis of Adenomyosis through Animal Models

Background: Adenomyosis is a common gynecological disorder traditionally viewed as “elusive”. Several excellent review papers have been published fairly recently on its pathogenesis, and several theories have been proposed. However, the falsifiability, explanatory power, and predictivity of these theories are often overlooked. Since adenomyosis can occur spontaneously in rodents and many other species, the animal models may help us unveil the pathogenesis of adenomyosis. This review critically tallies experimentally induced models published so far, with a particular focus on their relevance to epidemiological findings, their possible mechanisms of action, and their explanatory and predictive power. Methods: PubMed was exhaustively searched using the phrase “adenomyosis and animal model”, “adenomyosis and experimental model”, “adenomyosis and mouse”, and “adenomyosis and rat”, and the resultant papers were retrieved, carefully read, and the resultant information distilled. All the retrieved papers were then reviewed in a narrative manner. Results: Among all published animal models of adenomyosis, the mouse model of adenomyosis induced by endometrial–myometrial interface disruption (EMID) seems to satisfy the requirements of falsifiability and has the predictive capability and also Hill’s causality criteria. Other theories only partially satisfy Hill’s criteria of causality. In particular, animal models of adenomyosis induced by hyperestrogenism, hyperprolactinemia, or long-term exposure to progestogens without much epidemiological documentation and adenomyosis is usually not the exclusive uterine pathology consequent to those induction procedures. Regardless, uterine disruption appears to be a necessary but not sufficient condition for causing adenomyosis. Conclusions: EMID is, however, unlikely the sole cause for adenomyosis. Future studies, including animal studies, are warranted to understand how and why in utero and/or prenatal exposure to elevated levels of estrogen or estrogenic compounds increases the risk of developing adenomyosis in adulthood, to elucidate whether prolactin plays any role in its pathogenesis, and to identify sufficient condition(s) that cause adenomyosis.

Mode Switch of Ca2 + Oscillation-Mediated Uterine Peristalsis and Associated Embryo Implantation Impairments in Mouse Adenomyosis

Adenomyosis is a debilitating gynecological disease of the uterus with no medicinal cure. The tissue injury and repair hypothesis for adenomyosis suggests that uterine hyperperistalsis or dysperistalsis plays a pivotal role in establishing adenomyotic lesions. However, specific impairments in uterine peristalsis and the underlying cellular signals for these changes in adenomyosis remain elusive. Here, we report a precision-cut uterine slice preparation that preserves in vivo uterine architecture and generates peristalsis similar to that seen in the whole uterus. We found that uterine peristalsis in neonatal mice at day 14 and adult mice at day 55 presents as bursts with multiple peaks induced by intracellular Ca²⁺ oscillations. Using a mouse model of adenomyosis induced by tamoxifen, a selective estrogen receptor modulator, we discovered that uterine peristalsis and Ca²⁺ oscillations from adenomyotic uteri on days 14 and 55 become spikes (single peaks) with smaller amplitudes. The peak frequency of Ca²⁺ oscillations or peristalsis does not show a difference between control and adenomyotic mice. However, both the estimated force generated by uterine peristalsis and the total Ca²⁺ raised by Ca²⁺ oscillations are smaller in uteri from adenomyotic mice. Uteri from adenomyotic mice on day 14, but not on day 55, exhibit hyperresponsiveness to oxytocin. Embryo implantations are decreased in adenomyotic adult mice. Our results reveal a mode switch from bursts to spikes (rather than an increased peak frequency) of uterine Ca²⁺ oscillations and peristalsis and concurrent hyperresponsiveness to oxytocin in the neonatal stage are two characteristics of adenomyosis. These characteristics may contribute to embryo implantation impairments and decreased fertility in adenomyosis.

Animal Models of Adenomyosis

Adenomyosis is a nonmalignant uterine disorder in which endometrial tissue exists within and grows into the myometrium. Animal models have generated limited insight into the still-unclear pathogenesis of adenomyosis, provided a platform for preclinical screening of many drugs and compounds with potential as therapeutics, and elucidated mechanisms underlying the pain and fertility issues that occur in many women with the disease. Spontaneous adenomyosis has been studied in nonhuman primates, primarily in the form of case reports. Adenomyosis is routinely experimentally induced in mice through methods such as neonatal tamoxifen exposure, pituitary engraftment, and human tissue xenotransplantation. Several studies have also reported hormonal or environmental toxicant exposures that give rise to murine adenomyosis, and genetically engineered models have been created that recapitulate the human-like condition, most notably involving alteration of β-catenin expression. This review describes the animal models for adenomyosis and their contributions to our understanding of the factors underpinning the development of symptoms. Animal models represent a unique opportunity for understanding the molecular basis of adenomyosis and developing efficacious treatment options for affected women. Herein, we assess their different potentials and limitations with regard to identification of new therapeutic interventions and reflect on future directions for research and drug validation.

The development of the human uterus: morphogenesis to menarche

There is emerging evidence that early uterine development in humans is an important determinant of conditions such as ontogenetic progesterone resistance, menstrual preconditioning, defective deep placentation and pre-eclampsia in young adolescents. A key observation is the relative infrequency of neonatal uterine bleeding and hormone withdrawal at birth. The origin of the uterus from the fusion of the two paramesonephric, or Müllerian, ducts was described almost 200 years ago. The uterus forms around the 10th week of foetal life. The uterine corpus and the cervix react differently to the circulating steroid hormones during pregnancy. Adult uterine proportions are not attained until after puberty. It is unclear if the endometrial microbiome and immune response-which are areas of growing interest in the adult-play a role in the early stages of uterine development. The aim is to review the phases of uterine development up until the onset of puberty in order to trace the origin of abnormal development and to assess current knowledge for features that may be linked to conditions encountered later in life. The narrative review incorporates literature searches of Medline, PubMed and Scopus using the broad terms individually and then in combination: uterus, development, anatomy, microscopy, embryology, foetus, (pre)-puberty, menarche, microbiome and immune cells. Identified articles were assessed manually for relevance, any linked articles and historical textbooks. We included some animal studies of molecular mechanisms. There are competing theories about the contributions of the Müllerian and Wolffian ducts to the developing uterus. Endometrium features are suggestive of an oestrogen effect at 16-20 weeks gestation. The discrepancy in the reported expression of oestrogen receptor is likely to be related to the higher sensitivity of more recent techniques. Primitive endometrial glands appear around 20 weeks. Features of progestogen action are expressed late in the third trimester. Interestingly, progesterone receptor expression is higher at mid-gestation than at birth when features of endometrial maturation are rare. Neonatal uterine bleeding occurs in around 5% of neonates. Myometrial differentiation progresses from the mesenchyme surrounding the endometrium at the level of the cervix. During infancy, the uterus and endometrium remain inactive. The beginning of uterine growth precedes the onset of puberty and continues for several years after menarche. Uterine anomalies may result from fusion defects or atresia of one or both Müllerian ducts. Organogenetic differentiation of Müllerian epithelium to form the endometrial and endocervical epithelium may be independent of circulating steroids. A number of genes have been identified that are involved in endometrial and myometrial differentiation although gene mutations have not been demonstrated to be common in cases of uterine malformation. The role, if any, of the microbiome in relation to uterine development remains speculative. Modern molecular techniques applied to rodent models have enhanced our understanding of uterine molecular mechanisms and their interactions. However, little is known about functional correlates or features with relevance to adult onset of uterine disease in humans. Prepubertal growth and development lends itself to non-invasive diagnostics such as ultrasound and MRI. Increased awareness of the occurrence of neonatal uterine bleeding and of the potential impact on adult onset disease may stimulate renewed research in this area.

m6A RNA Methylation Regulators Contribute to Eutopic Endometrium and Myometrium Dysfunction in Adenomyosis

Adenomyosis is a prevalent, estrogen-dependent uterine disorder wherein endometrial cells are abnormally present in the myometrium and are surrounded by hyperplastic/hypertrophic smooth muscle. Its etiology is unclear, although endometrial cell invasion into the myometrium has been postulated. RNA methylation, particularly N6-methyladenosine (m6A), plays an important role in regulating various physiological processes and invasive disorders. The goal of this in silico and lab-based experimental study was to explore a possible role for m6A in adenomyosis. Gene expression profiles of both the endometrium and myometrium of women with adenomyosis (cases) and without disease (controls) were obtained from the publicly available Gene Expression Omnibus (GEO) database. In the endometrium, STRING database analysis revealed that METTL3 functions as a "hub" gene of m6A RNA methylation regulators, and the genes involved in m6A regulation, including METTL3, FTO, ZC3H13, and YTHDC1 expression, were significantly decreased in cases versus controls. Functional, co-expression, and correlational analyses of endometrium from cases versus controls revealed decreased total m6A levels, induced by METTL3, and the downstream elevated insulin-like growth factor-1(IGF1) and D-Dopachrome Tautomerase (DDT), with the latter two having known functions in epithelial proliferation and cell migration, which are important processes in the pathogenesis of adenomyosis in endometrium. m6A RNA methylation regulators, including RBM15/15B, ALKBH5, FTO, YTHDF1/2, KIAA1429, HNRNPC, METTL3, ZC3H13, and YTHDC2, were also differentially expressed in the myometrium from cases versus controls. We validated decreased total m6A levels and differential expression of m6A RNA methylation regulators in the myometrium of patients with adenomyosis using qRT-PCR, immunohistochemistry and tissues available from our biorepository. Possible target genes, including cadherin 3(CDH3), sodium channelβ-subunit 4 (SCN4B), and placenta-specific protein 8 (PLAC8), which are involved in cell adhesion, muscle contraction and immune response in the myometrium of adenomyosis patients were also validated. Thus, through extensive public database mining and validation of select genes, this study, for the first time, implicates m6A and its methylation regulators in the pathogenesis of adenomyosis. Follow on functional studies are anticipated to elucidate mechanisms involving m6A and its regulators and down-stream effectors in the pathogenesis of this enigmatic reproductive disorder and potentially identify druggable targets to control its associated symptoms.

Developmental Toxicant Exposure Is Associated with Transgenerational Adenomyosis in a Murine Model

The common environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or, commonly, dioxin) is a known endocrine disruptor that has been linked to the development of endometriosis in experimental models. Using a murine model, we previously demonstrated that in utero TCDD exposure promotes the transgenerational development of an “endometriosis-like” uterine phenotype consisting of reduced responsiveness to progesterone, as well as subfertility and an increased risk of preterm birth. Because adenomyosis is frequently observed as a comorbidity in women with endometriosis, herein we sought to determine the incidence of adenomyosis in nonpregnant mice with a history of direct or indirect TCDD exposure. Using histologic assessment and immunohistochemical staining, we analyzed murine uteri for adenomyosis, microvessel density, and expression of estrogen receptors alpha and beta (ESR1 and ESR2). Our studies revealed that unexposed control mice did not exhibit adenomyosis, whereas this disease was frequently observed in mice with a history of early-life TCDD exposure. A transgenerational impact of developmental TCDD exposure was demonstrated, because a subset of mice with only an indirect exposure (F3) also exhibited adenomyosis. Microvessel density within the uterus was significantly higher in all groups of TCDD-exposed mice compared with control animals, with density correlated to the severity of disease. Both ESR1 and ESR2 proteins exhibited alterations in expression in experimental mice compared with controls. Similar to women with endometriosis, we observed a significant reduction in the ratio of Esr1:Esr2 mRNA in all F1 mice compared with controls. Although this retrospective study was not designed to specifically address mechanisms associated with the development of adenomyosis, our data suggest that developmental TCDD exposure permanently alters adult steroid responses, which may contribute to the transgenerational development of adenomyosis.

The pathophysiology of uterine adenomyosis: an update

The diagnosis of adenomyosis using noninvasive techniques such as vaginal ultrasounds and magnetic resonance has clear clinical applications and has renewed the interest in the pathogenesis of uterine adenomyosis. However, the research remains hampered by the lack of consensus on the classification of lesions. Magnetic resonance imaging and transvaginal ultrasound have comparable diagnostic accuracy. Minimal interventional biopsy techniques have recently been introduced. This article reviews human and animal studies and provides an update on the pathophysiology of adenomyosis. Recent views on the pathogenesis and links with endometriosis are discussed.

Estrogen and progesterone receptor isoform distribution through the menstrual cycle in uteri with and without adenomyosis

OBJECTIVE

To test the hypothesis that the expression of the different isoforms of the estrogen receptor alpha (ER-α) and beta (ER-β) and the progesterone receptor A (PR-A) and B (PR-B) would be differentially modulated in uteri with adenomyosis compared with controls and that modulation would be related to the menstrual cycle.

DESIGN

Case control, blinded comparison.

SETTING

University department.

PATIENT(S)

54 premenopausal women with and 35 without uterine adenomyosis as the sole pathology.

INTERVENTION(S)

Multiple samples studied using immunohistochemistry for estrogen and progesterone receptors.

MAIN OUTCOME MEASURE(S)

Histomorphometric analysis of receptor expression.

RESULT(S)

The ER-α expression in the adenomyotic endometrium was different from that of the normal endometrium and the foci in the midsecretory phase of the cycle, but expression of ER-α in the inner and outer myometrium was not statistically significantly different. The ER-β expression was statistically significantly elevated in the adenomyotic functionalis gland during the proliferative phase and throughout the myometrium across the entire menstrual cycle. Expression of PR-A was similar to that of PR-B, with reduced expression in the basalis stroma, and inner and outer myometrium in the adenomyotic samples. The pattern of ER-β, PR-A, and PR-B expression was similar in the endometrial basalis and adenomyotic foci.

CONCLUSION(S)

These data suggest ER-β expression and the lack of PR expression are related to the development and/or progression of adenomyosis and might explain the poor response of adenomyosis-associated menstrual symptoms to progestational agents.

Enhanced invasion of stromal cells from adenomyosis in a three-dimensional coculture model is augmented by the presence of myocytes from affected uteri

OBJECTIVE

To compare endometrial stromal cell invasion from women with and without adenomyosis and the effect of myometrial cells using a three-dimensional coculture.

DESIGN

Case-controlled blinded comparison.

SETTING

University department.

PATIENT(S)

Premenopausal women with and without uterine adenomyosis.

INTERVENTION(S)

Human endometrial stromal and myometrial cells were grown in a three-dimensional coculture with crossover between cells from uteri with and without adenomyosis. Surface-enhanced laser desorption/ionization-time of flight-mass spectrometry proteomic analysis was performed on culture supernatants.

MAIN OUTCOME MEASURE(S)

Depth of stromal cell invasion into collagen matrix and protein expression profiles.

RESULT(S)

The depth of invasion for adenomyosis stromal cells (AS) was statistically significantly higher than controls (CS) whether grown on plain collagen, control muscle (CM), or adenomyosis muscle (AM). Coculture with AM enhanced invasion of both CS and AS. Enhanced invasion by AS was more marked in cocultures with AM than CM. Proteomic analysis identified differences that may account for the invasiveness and also many similarities between secretory products related to the disease status.

CONCLUSION(S)

Enhanced stromal invasion in adenomyosis is influenced by the myometrium in the in vitro coculture model. This suggests that adenomyosis may be a disease of both the endometrial stroma and myometrium.