The pathophysiology of endometriosis and adenomyosis: tissue injury and repair

Overview of crosstalk between stromal and epithelial cells in the pathogenesis of adenomyosis and shared features with deep endometriotic nodules

Since the first description of adenomyosis more than 150 years ago, multiple hypotheses have attempted to explain its pathogenesis. Indeed, research over recent years has greatly enhanced our knowledge of the underlying causes. This has opened up avenues for the development of strategies for both disease prevention and treatment of its main symptoms, such as pelvic pain, heavy menstrual bleeding, and infertility. However, the current means are still largely ineffective, so it is vital that we shed light on the pathways involved. Dysregulated mechanisms and aberrant protein expression have been identified as contributing factors in interactions between endometrial epithelial and stromal cells, ultimately leading to the growth of adenomyotic lesions. These include collective cell migration, epithelial-to-mesenchymal transition, hormonal influence, and signaling from non-coding RNAs and extracellular vesicles. We provide a concise summary of the latest insights into the crosstalk between glands and stroma in ectopic adenomyotic lesion formation. While there is an abundance of literature on similarities between adenomyosis and deep endometriosis, there are insufficient data on the cytochemical, molecular, and pathogenetic mechanisms of these two disorders. However, various shared features, including alterations of cell adhesion molecules, abnormal hormone regulation, and the presence of cancer-driving mutations and epigenetic modifications, have been identified. Nevertheless, the pathogenic mechanisms that contribute to the cause and development of these enigmatic diseases have not been fully elucidated yet.

Occult clear cell carcinoma arising from oxidative stress‑exposed cystic adenomyosis: A case report

Although adenomyosis is a benign uterine disease, it can turn malignant in rare instances. Cystic adenomyosis is a rare variation of adenomyosis, arising from which 8 cases of clear cell carcinoma have been reported. However, to the best of our knowledge, there have been no previous reports describing the mechanism by which clear cell carcinoma develops from cystic adenomyosis. The present report documents a case of a 73-year-old woman who was referred to Kanazawa University Hospital (Kanazawa, Japan) because of cystic adenomyosis, with a solid part inside the cyst. The patient was diagnosed with cystic adenomyosis at Shonan Obstetrics and Gynecology Hospital (Hakusan, Japan) 17 years prior; however, the size of the cyst increased after menopause. Therefore, malignant transformation was suspected, which warranted simple abdominal hysterectomy and bilateral salpingo-oophorectomy. The final diagnosis of the present case was uterine corpus cancer, clear cell carcinoma, stage IA. Immunohistochemical staining revealed that the normal and transitional atypical epithelial cells lining the cyst wall, in addition to the clear cell carcinoma cells (which were inside mural nodules located on the cyst wall), were positive for 8-hydroxy-20-deoxyguanosine. This observation suggested the presence of chronic oxidative stress around the cystic adenomyosis. Therefore, the present case suggests the possible involvement of chronic oxidative stress in the malignant transformation of cystic adenomyosis to clear cell carcinoma. This mechanism of malignant transformation of cystic adenomyosis appears to be similar to that of the malignant transformation of endometriotic cysts. Therefore, if the size of the cystic adenomyosis increases after menopause or if the solid part appears in the cyst in future cases, then the possibility of malignant transformation should be considered.

Comprehensive analysis of circRNA-miRNA-mRNA regulatory network and novel potential biomarkers in eutopic endometrium of adenomyosis

Adenomyosis (ADS) is a common gynecological disorder, and its pathogenesis remains unclear. This study explores the functions of circRNAs in the eutopic endometrium of ADS and their diagnostic efficacy for ADS. High-throughput RNA sequencing was performed on 12 eutopic endometrial samples from ADS patients and 3 control endometrial samples. Additionally, circRNAs were analyzed in conjunction with clinical features. A competitive endogenous RNA network was established based on bioinformatics analysis, comprising 3 circRNAs, 1 miRNA, and 13 mRNAs. In the ADS group, the expression levels of hsa_circ_0008959 and SLC15A4 were significantly reduced, while hsa-miR-124-3p expression was increased. SLC15A4 was associated with cell proliferation and invasion. Decreased expression of hsa_circ_0008959 and SLC15A4, along with high VAS scores and elevated hsa-miR-124-3p levels, were identified as risk factors for ADS development. The combination of hsa_circ_0008959 and VAS scores demonstrated the highest diagnostic value for ADS.

miR-141-3p Regulates the Proliferation and Apoptosis of Endometrial-Myometrial Interface Smooth Muscle Cells in Adenomyosis Via JAK2/STAT3 Pathway

Adenomyosis (ADS) is a common benign gynecological disease. Abnormal proliferation at the endometrial-myometrial interface (EMI) plays a crucial role in the occurrence and progression of ADS. miR-141-3p is associated with cell proliferation and apoptosis. However, the specific mechanism of miR-141-3p in the etiology of ADS is still unknown. In this study, we explored the effects of miR-141-3p on the proliferation and apoptosis of ADS EMI smooth muscle cells (SMCs). We collected EMI tissues for the primary culture of SMCs from 25 patients diagnosed with ADS and 20 without ADS. Real-time quantitative polymerase chain reaction and western blot were used to measure the mRNA and protein expression levels of miR-141-3p, JAK2, STAT3, phospho-JAK2, and phospho-STAT3 in ADS EMI SMCs. The cell counting kit 8 assay and flow cytometry analysis were used to evaluate the proliferation and apoptosis of EMI SMCs. The miR-141-3p mimic/inhibitor was used to increase or decrease the expression level of miR-141-3p. We added WP1066 to block the phosphorylation of JAK2/STAT3 pathway components. The miR-141-3p levels were decreased, while JAK2 and STAT3 levels were increased in ADS EMI SMCs. miR-141-3p overexpression significantly inhibited the proliferation and enhanced the apoptosis of EMI SMCs, whereas a decrease in miR-141-3p expression level was connected to the opposite results. Meanwhile, inactivated JAK2/STAT3 pathway decreased proliferation and enhanced apoptosis of EMI SMCs after WP1066 treatment. Furthermore, rescue experiments confirmed that the JAK2/STAT3 pathway was the downstream pathway of miR-141-3p and reduced the effect of miR-141-3p on the proliferation and apoptosis of EMI SMCs. These results demonstrate that miR-141-3p regulates the proliferation and apoptosis of ADS EMI SMCs by modulating the JAK2/STAT3 pathway.

Prevalence of adenomyosis features in women scheduled for assisted reproductive treatment, using the Morphological Uterus Sonographic Assessment group definitions

INTRODUCTION

Studies that use standardized ultrasonographic criteria to diagnose adenomyosis in subfertile women are needed. These would improve the understanding of the disease burden and enable further studies on its impact on fertility and assisted reproductive treatment (ART) outcome. The aim of this study was to determine the prevalence of different features of adenomyosis in women scheduled for their first ART, diagnosed at two (2D) and three-dimensional (3D) transvaginal ultrasonography (TVUS) using the revised Morphological Uterus Sonographic Assessment (MUSA) group definitions.

MATERIAL AND METHODS

This was a prospective, observational cross-sectional study of subfertile women aged 25 to ≤39 years, that were referred to a university hospital for their first ART between December 2018 and May 2021. Of 1224 eligible women, 1160 women fulfilled the inclusion criteria and consented to participate in the study. All women underwent a systematic 2D and 3D TVUS examination. The primary outcome was the presence of direct and indirect features of adenomyosis, as proposed by the MUSA group. Secondary outcomes were to describe the ultrasonographic characteristics of the different features, as well as any difference in the diagnostics at 2D or 3D TVUS and any association with clinical characteristics such as endometriosis.

RESULTS

At least one direct or indirect feature of adenomyosis was observed in 272 (23.4%, 95% confidence interval [CI] 21.0-25.9) women. Direct features that are pathognomonic for the disease were observed in 111 (9.6%, 95% CI, 7.9-11.3) women. Direct features were visible only at 3D TVUS in 56 (4.8%, 95% CI 3.6-6.1) women, that is, 56/111 (50.5%) of women with at least one direct adenomyosis feature. Direct features were more common in women with endometriosis (OR 2.8, 95% CI 1.8-4.3).

CONCLUSIONS

We found than one in 10 women scheduled for ART had direct features of adenomyosis at ultrasound examination. The present study suggests that the use of 3D TVUS is an important complement to 2D in the diagnostics of adenomyosis. Our results may further improve the counseling of women scheduled for ART and enables future studies on the impact of different features of adenomyosis on subfertility, ART results and obstetric outcomes.

The Known, the Unknown and the Future of the Pathophysiology of Endometriosis

Endometriosis is one of the most common causes of chronic pelvic pain and infertility, affecting 10% of women of reproductive age. A delay of up to 9 years is estimated between the onset of symptoms and the diagnosis of endometriosis. Endometriosis is currently defined as the presence of endometrial epithelial and stromal cells at ectopic sites; however, advances in research on endometriosis have some authors believing that endometriosis should be re-defined as "a fibrotic condition in which endometrial stroma and epithelium can be identified". There are several theories on the etiology of the disease, but the origin of endometriosis remains unclear. This review addresses the role of microRNAs (miRNAs), which are naturally occurring post-transcriptional regulatory molecules, in endometriotic lesion development, the inflammatory environment within the peritoneal cavity, including the role that cytokines play during the development of the disease, and how animal models have helped in our understanding of the pathology of this enigmatic disease.

Increased risk of placenta previa and preterm birth in pregnant women with endometriosis/adenomyosis: A propensity-score matching analysis of a nationwide perinatal database in Japan

AIM

We aimed to investigate the associations of endometriosis and adenomyosis with pregnancy complications by using a large-scale Japanese database.

METHODS

We retrospectively analyzed 145 590 singleton pregnancies from the Japan Perinatal Registry Network Database. Pregnant women registered as having endometriosis or adenomyosis were designated as the case group (EA), whereas the control group (non-EA) was selected using propensity-score matching adjusted for variables such as age, parity, BMI, smoking history, and the use of assisted reproductive technology. The main outcomes included placental malposition, preterm birth, and hypertensive disorders of pregnancy (HDP).

RESULTS

In total, 1203 patients from both the EA and non-EA groups were matched and evaluated. The EA group showed significantly higher rates of placenta previa (odds ratio [OR], 3.01; 95% confidence interval [CI], 1.84-4.92), low-lying placenta (OR, 2.02; 95% CI, 1.06-3.86), and preterm birth (OR, 1.44; 95% CI, 1.13-1.84) than the non-EA group. However, no significant difference was observed in the incidence of HDP (OR, 1.22; 95% CI, 0.90-1.66).

CONCLUSION

The use of propensity-score matching to analyze a nationwide perinatal database in Japan clarified that EA was associated with increased pregnancy complications, specifically placental malposition, including placenta previa and low-lying placenta, and preterm birth, but not with HDP.

[Physiotherapeutic differential diagnosis of back pain associated with endometriosis]

BACKGROUND

Endometriosis (EM) is one of the most common gynecologic conditions in our society. The diagnosis takes an average of 7 to 10 years. To shorten this period, this syndrome needs more attention. The aim of this article is to show overlaps between EM and low back pain (LBP) and to describe their relevance for physiotherapeutic screening.

OBJECTIVES

What clinical signs do the syndromes EM and LBP have in common and to what extent can physiotherapeutic screening take gynecological aspects into account and be adapted accordingly?

RESULTS

To answer this question, the two syndromes were screened for overlaps. These overlaps were then related to the existing literature and case studies. The current research situation shows overlaps of the two syndromes with regard to the etiology, the pain mechanism as well as a psychosocial aspect. The literature shows that more women than men are affected by LBP and other chronic pain syndromes. EM occurs almost exclusively in women and, like LBP, is considered a chronic pain syndrome. Thus, a common pain mechanism of the two syndromes is discussed in the literature. The most frequent overlap of the two syndromes is shown by the occurrence of LBP as a frequent symptom of EM. This connection can be justified by structural causes as well as by a reflex pain presentation.

CONCLUSION

In a physiotherapeutic setting, evidence of EM can be observed in the history and physical examination. Considering these factors may help shorten the diagnosis time of endometriosis by referring for further evaluation if gynecologic involvement is suspected in LBP. A comprehensive history is important and should cover urologic, gynecologic, as well as sexual history. In this article, the term woman is used to refer to the biological female sex and is not related to individual gender identity. The clinical picture mainly affects women, which is why in the following work, as far as it concerns the people suffering from the disease, it is not used in the opposite sense.

Adenomyotic Lesions Are Induced in the Mouse Uterus after Exposure to NSAID and EE2 Mixtures at Environmental Doses

The aim of this study was to assess the long-term effect of exposure to environmentally relevant doses of non-steroidal anti-inflammatory drugs (NSAIDs; ibuprofen, and diclofenac) and 17β-ethinylestradiol (EE2) on the mouse uterus. NSAID-EE2 mixtures were administered in the drinking water from gestational day 8 until 8 weeks post-birth (i.e., during embryo development, lactation, puberty, and sexual maturity). The incidence of adenomyosis lesions (presence of endometrial glands in the inner myometrium) increased up to 60% in the uterus of 8-week-old exposed females (F1) and to 85% in F2 females (exposed father). Histological analysis revealed aberrant proliferation and apoptosis, vacuolization of epithelial cells, and increased incidence of abnormal glands in the luminal and glandular epithelium in F1 and F2 uteri. Moreover, myofibroblast proportion (alpha-smooth muscle actin (α-SMA) expression analysis) and collagen expression (Picrosirius red stain; a fibrosis hallmark) were increased in F1 and F2 endometrium. Connexin-43 was aberrantly distributed in the endometrial stroma and glands of F1 and F2 uteri. Conversely, uterine 17β-estradiol and progesterone levels were not affected in F1 and F2 females. These findings demonstrated that in mice, chronic exposure to NSAID and EE2 mixtures at environmental doses intergenerationally affects uterine physiology, particularly the endometrium. It may serve as a model to study the pathophysiology of human adenomyosis.

Endometriosis and adenomyosis: Similarities and differences

Deep endometriosis and uterine adenomyosis are two frequently encountered conditions affecting approximately 200 million women worldwide. They are closely related, showing similar histological patterns and multiple common pathogenic features, and share the same symptoms. It is therefore not surprising that they are often thought to have a common developmental origin. Indeed, both deep endometriosis and adenomyosis appear to derive from estrogen-dependent overproliferation of endometrial tissue and its subsequent implantation in ectopic sites. Although the scientific community has shown increasing interest in these diseases over recent years, neither pathogenesis has yet been elucidated, so there are currently no efficient treatment options. Understanding the mechanisms underlying disease development, as well as discerning their relationship, are key to improving clinical management for millions of patients. The aims of this review are to summarize current knowledge on deep endometriosis and adenomyosis pathogeneses and discuss the possibility that these two entities are actually differential phenotypes of the same disease.

Establishment of an immortalized cell line derived from human adenomyosis ectopic lesions

Because adenomyosis (AM) ectopic primary cells are hard to come by, have a short lifespan, and the characteristics that alter over time, their utility in AM research is constrained. This study aimed to establish a line of immortalized human adenomyosis ectopic cell (ihAMEC) to change this situation. Primary cells were obtained from AM ectopic lesion tissue and then infected with Simian Vacuolating Virus 40 Tag (SV40 T) lentivirus and screened to establish immortalized cells. We verified the main features and found that the ihAMEC could be cultured for more than 50 generations and the proliferation ability of ihAMEC was more active than that of primary cells. The cytoskeleton and cell types of ihAMEC were similar to primary cells and maintained a normal karyotype. The expression of epithelial-mesenchymal transition (EMT) markers, estrogen-metabolizing proteins, and estrogen/progesterone receptors in ihAMEC was similar to the expression seen in primary cells. In addition, the response of ihAMEC under estrogen treatment and Lipopolysaccharide intervention is similar to primary cells. The clonogenic ability of ihAMEC was lower than tumor cells and did not form tumors in tumorigenicity assays. Thus, ihAMEC can be used as in vitro cellular model for pathogenesis and drug development studies regarding AM.

Proposal for targeted, neo-evolutionary-oriented, secondary prevention of early-onset endometriosis and adenomyosis. Part I: pathogenic aspects

The potential for repeated ovulation and menstruation is thought to have provided a Darwinian advantage during the Palaeolithic. Reproductive conditions remained relatively stable until the pre-industrial era, characterized by late menarche, very young age at first birth, multiple pregnancies, and prolonged periods of lactational amenorrhoea. For hundreds of thousands of years, menstruators experienced few ovulatory cycles, even though they were genetically adapted to ovulate and menstruate every month. In the post-industrial era, the age at menarche gradually declined, the age at first birth progressively increased, and breastfeeding became optional and often of short duration. This created a mismatch between genetic adaptation and socio-environmental evolution, so that what was initially a probable reproductive advantage subsequently contributed to increased susceptibility to diseases associated with lifetime oestrogen exposure, such as ovarian, endometrial and breast cancer and, hypothetically, also those associated with the number of ovulatory menstruations, such as endometriosis and adenomyosis. The incidence of endometriosis shows a steep and progressive increase around the age of 25 years, but given the consistently reported delay in diagnosis, the actual incidence curve should be shifted to the left, supporting the possibility that the disease has its roots in adolescence. This raises the question of whether, from an evolutionary point of view, anovulation and amenorrhoea should not still be considered the physiological state, especially in the postmenarchal period. However, an increase in the frequency of endometriosis in recent decades has not been demonstrated, although this deserves further epidemiological investigation. In addition, as endometriosis occurs in a minority of individuals exposed to retrograde menstruation, other important pathogenic factors should be scrutinised. Research should be resumed to explore in more detail the transtubal reflux of not only blood, but also endometrial cells, and whether they are systematically present in the peritoneal fluid after menstruation. If repetitive ovulatory menstruation during the early reproductive years is shown to increase the risk of endometriosis and adenomyosis development and progression in susceptible individuals, hormonal interventions could be used as secondary prevention in symptomatic adolescents.

Endometrial Stem Cells: Orchestrating Dynamic Regeneration of Endometrium and Their Implications in Diverse Endometrial Disorders

The human endometrium, a vital component of the uterus, undergoes dynamic changes during the menstrual cycle to create a receptive environment for embryo implantation. Its remarkable regenerative capacity can be attributed to the presence of tissue-resident stem cell populations within the endometrium. Despite variations in characteristics among different subtypes, endometrial stem cells exhibit notably robust self-renewal capacity and the ability to differentiate into multiple lineages. This review offers a comprehensive insight into the current literature and recent advancements regarding the roles of various endometrial stem cell types during dynamic regeneration of the endometrium during the menstrual cycle. In addition, emerging evidence suggests that dysfunction or depletion of endometrial stem cells may play critical roles in the development and progression of various endometrial disorders, such as endometriosis, uterine fibroids, adenomyosis, infertility, and endometrial cancer. Therefore, we also highlight potential roles of endometrial stem cells in the development and progression of these endometrial diseases, including their ability to accumulate genetic mutations and express genes associated with endometrial diseases. Understanding the dynamic properties of the endometrium and the roles of endometrial stem cells in various endometrial disorders will shed light on potential therapeutic strategies for managing these conditions and improving women's fertility outcomes.

Are Adenomyosis and Endometriosis Phenotypes of the Same Disease Process?

In recent literature reviews, we concluded that the possibility that endometrial molecular aberrations are the sole or a necessary determinant of endometriosis and the Tissue Injury and Repair (TIAR) theory are yet to be convincingly proven. Here, we critically examine the theory that adenomyosis and endometriosis represent different phenotypes of a single disease. A common etiopathology for adenomyosis and endometriosis has been suggested because both conditions entail the presence of endometrial tissue at locations other than the lining of the uterus. There are wide differences in reported disease incidence and prevalence and, consequently, in estimates of the coexistence of both conditions. There are some similarities but also differences in their clinical features and predisposing factors. Each condition has a range of subtypes. These differences alone pose the question of whether subtypes of endometriosis and adenomyosis have different etiopathologies, and, in turn, this raises the question of whether they all share a common etiology. It is debatable whether the recognized differences between the eutopic endometrium in adenomyosis and endometriosis compared to those in unaffected women are the cause or the effect of the disease. The finding of common mutations, particularly of KRAS, lend support to the notion of shared predisposing factors, but this alone is insufficient evidence of causation.

Junctional zone thickening: an endo-myometrial unit disorder

Adenomyosis is a disease defined by histopathology, mostly of hysterectomy specimens, and classification is challenged by the disagreement of the histologic definition. With the introduction of Magnetic Resonance Imaging (MRI) and two- and three-dimensional ultrasound, the diagnosis of adenomyosis became a clinical entity. In MRI and US, adenomyosis ranges from thickening of the inner myometrium or junctional zone to nodular, cystic, or diffuse lesions involving the entire uterine wall, up to a well-circumscribed adenomyoma or a polypoid adenomyoma. The absence of an accepted classification and the vague and inconsistent terminology hamper basic and clinical research. The sub-endometrial halo seen at US and MRI is a distinct entity, differing from the outer myometrium by its increased nuclear density and vascular structure. The endometrium and the sub-endometrial muscularis or archimetra are of Müllarian origin, while the outer myometrium is non-Mullerian mesenchymal. The junctional zone (JZ) is important for uterine contractions, conception, implantation, and placentation. Thickening of the JZ can be considered inner myometrium adenomyosis, with or without endometrial invasion. Changes in the JZ should be considered a different entity than myometrial clinically associated with impaired conception, implantation, abnormal uterine bleeding, pelvic pain and obstetrical outcome. Pathology of the basal endometrium and JZ is a separate entity and should be identified as an endo-myometrial unit disorder (EMUD).

Current Medical Therapy for Adenomyosis: From Bench to Bedside

Adenomyosis, characterized by the growth of endometrial tissue within the uterine wall, poses significant challenges in treatment. The literature primarily focuses on managing abnormal uterine bleeding (AUB) and dysmenorrhea, the main symptoms of adenomyosis. Nonsteroidal anti-inflammatory drugs (NSAIDs) and tranexamic acid provide limited support for mild symptoms or symptom re-exacerbation during hormone therapy. The levonorgestrel-releasing intrauterine system (LNG-IUS) is commonly employed in adenomyosis management, showing promise in symptom improvement and reducing uterine size, despite the lack of standardized guidelines. Dienogest (DNG) also exhibits potential benefits, but limited evidence hinders treatment recommendations. Danazol, while effective, is limited by androgenic side effects. Combined oral contraceptives (COCs) may be less effective than progestins but can be considered for contraception in young patients. Gonadotropin-releasing hormone (GnRH) agonists effectively manage symptoms but induce menopausal symptoms with prolonged use. GnRH antagonists are a recent option requiring further investigation. Aromatase inhibitors (AIs) show promise in alleviating AUB and pelvic pain, but their safety necessitates exploration and limited use within trials for refractory patients. This review highlights the complexity of diagnosing adenomyosis, its coexistence with endometriosis and uterine leiomyomas, and its impact on fertility and quality of life, complicating treatment decisions. It emphasizes the need for research on guidelines for medical management, fertility outcomes, long-term effects of therapies, and exploration of new investigational targets. Future research should optimize therapeutic strategies, expand our understanding of adenomyosis and its management, and establish evidence-based guidelines to improve patient outcomes and quality of life.

Outcome of uterine functional structures protection by fertility preservative PUSH surgery in diffuse adenomyosis

This study reports the outcomes of an innovative fertility-preserving surgery for the treatment of diffuse adenomyosis that is known as a surgery for protection of uterine structure for healing (PUSH Surgery). Developed at Peking University Shenzhen Hospital, PUSH Surgery aims to achieve radical excision of adenomyotic lesions by reconstructing the uterus with overlapping muscle flaps to promote optimal healing of the uterine wall and reduce the risk of scar rupture in subsequent pregnancies. PUSH Surgery was performed on 146 patients with diffuse adenomyosis, with uteri measuring from 8 to 16 gestational weeks and an average volume of 230 ± 150cm³. Regular follow-up was conducted for up to 156 months, revealing a significant reduction in VAS pain scores from 9.4 ± 1.2 before the surgery to 0.3 ± 0.8 and 0.6 ± 1.0 at 1 and 2 years post-surgery, respectively, with a continuous alleviation rate of 96.4% after the operations. Notably, 100% of patients with severe menorrhagia reported normal menstruation volumes within 2 years. Additionally, 31 patients attempted to conceive, resulting in a 58% postoperative pregnancy rate and a 60.0% intrauterine live embryo rate. Operation-related complications occurred in 2.7% of patients, with a 3.6% recurrence rate after more than 2 years of follow-up. Importantly, no cases of uterine rupture or severe complications were observed in the pregnant patients. In conclusion, PUSH Surgery offers a promising approach for the radical excision of adenomyotic lesions, promoting improved tissue healing and significant symptom relief.

Fertility and Obstetric Outcomes of Assisted Reproductive Technology (ART) in Women With Adenomyosis Following Gonadotropin-Releasing Hormone Agonist Therapy: A Single-Center Experience

INTRODUCTION

Adenomyosis is an ambiguous disorder causing a wide variety of implications from dysmenorrhea, heavy menstrual bleeding, and infertility to pregnancy complications. Adenomyosis is associated with altered endocrine and inflammatory milieu, resulting in impaired implantation and reduced fertility potential. It is also associated with increased incidence of obstetric complications such as miscarriage, antepartum hemorrhage, placental mal-position, hypertensive disorders, small for gestational age-intrauterine growth restriction (SGA-IUGR), cesarean section, preterm labor, preterm premature rupture of membranes (PPROM), and neonatal intensive care unit (NICU) admissions.

OBJECTIVE

The aim of our study was to investigate the fertility and obstetric outcomes in women with adenomyosis treated with GnRH agonists compared to controls with normal uteri undergoing in-vitro fertilization (IVF) at our center, thereby establishing the role of gonadotropin-releasing hormone (GnRH) agonists in managing sub-fertile women with adenomyosis.

MATERIALS AND METHODS

We carried out a retrospective cohort study at our hospital to analyze the effects of adenomyosis on IVF and pregnancy outcomes. This study (n=83) involves women with adenomyosis between the ages of 21 and 37 years who were followed up at our center between 2013 and 2022. The controls (n=83) were selected from women who underwent IVF-intracytoplasmic sperm injection (IVF-ICSI) for tubal or mild male factor infertility with normal appearing uterus within the same time frame. Women with adenomyosis were given GnRH agonist as long/ultralong agonist protocol before controlled ovarian stimulation or as down-regulated frozen embryo transfer (FET). The length of suppression was between one and six months based on the size of the uterus and response to treatment. Fertility and obstetric outcomes were analyzed.

RESULTS

The implantation rates were found to be equivocal: 54.2% and 53% in the adenomyosis and control groups, respectively (p=0.208). The cumulative live birth rate was 50.6% and 48.2% in the study and control groups, respectively (p=0.341). The biochemical pregnancy rate and the first- and second-trimester miscarriage rates were not significantly different between the group with adenomyosis and the group with normal uterus. The incidence of preterm deliveries and antepartum hemorrhage was found to be significantly increased in the study group.

CONCLUSION

Medical management in women with adenomyosis optimizes the live birth rates giving results at par with the control population.

Adenomyosis and Infertility: A Literature Review

Background and Objectives: Adenomyosis (the presence of ectopic endometrial glands and stroma below the endometrial-myometrial junction) is a benign condition which is increasingly diagnosed in younger women suffering from infertility. The aim of this narrative review was to study the pathophysiology and prevalence of adenomyosis, the mechanisms causing infertility, treatment options, and reproductive outcomes in infertile women suffering from adenomyosis. Materials and Methods: A literature search for suitable articles published in the English language was performed using PubMed from January 1970 to July 2022. Results: The literature search retrieved 50 articles that met the purpose of this review and summarized the most recent findings regarding the accuracy of diagnostic methods, pathophysiology, and the prevalence of adenomyosis and optimal strategies for the treatment of infertile women with adenomyosis. Conclusions: Adenomyosis is a common gynecological disorder, affecting women of reproductive age. It negatively affects in vitro fertilization, pregnancy and the live birth rate, as well as increases the risk of miscarriage. With the advent of non-invasive diagnoses with MRI and TVUS, the role of adenomyosis in infertility has been better recognized. Overall, more randomized controlled trials (RCTs) are needed to provide strong data on the accuracy of diagnostic methods, the pathophysiology and the prevalence of adenomyosis, the fertility outcomes of patients and the optimal strategy for the treatment.

Exosomes: potential diagnostic markers and drug carriers for adenomyosis

Adenomyosis is a common benign gynecological disorder and an important factor leading to infertility in fertile women. Adenomyosis can cause deep lesions and is persistent and refractory in nature due to its tumor-like biological characteristics, such as the ability to implant, adhere, and invade. The pathogenesis of adenomyosis is currently unclear. Therefore, new therapeutic approaches are urgently required. Exosomes are nanoscale vesicles secreted by cells that carry proteins, genetic materials and other biologically active components. Exosomes play an important role in maintaining tissue homeostasis and regulating immune responses and metabolism. A growing body of work has shown that exosomes and their contents are key to the development and progression of adenomyosis. This review discusses the current research progress, future prospects and challenges in this emerging therapeutic tool by providing an overview of the changes in the adenomyosis uterine microenvironment and the biogenesis and functions of exosomes, with particular emphasis on the role of exosomes and their contents in the regulation of cell migration, proliferation, fibrosis formation, neovascularization, and inflammatory responses in adenomyosis.

Contemporary evaluation of women and girls with abnormal uterine bleeding: FIGO Systems 1 and 2

Abnormal uterine bleeding (AUB) is common, often debilitating, and may affect over 50% of reproductive-aged women and girls. Whereas AUB is a collection of symptoms that include intermenstrual bleeding and abnormalities in period duration, cycle length, and regularity, it is heavy menstrual bleeding (HMB) that is most contributory to iron deficiency and related anemia. It is apparent that AUB, in general, and HMB, in particular, remain underrecognized and underreported. FIGO created two systems for assessing and classifying AUB. FIGO System 1 defines the bleeding pattern using four primary descriptors: frequency, duration, regularity, and flow volume. FIGO System 2 provides a structured classification system of possible causes of AUB, using the acronym PALM-COEIN. "PALM" refers to structural causes of AUB (Polyp, Adenomyosis, Leiomyoma, Malignancy), and "COEI" refers to nonstructural causes (Coagulopathy, Ovulatory dysfunction, Endometrial, and Iatrogenic). The "N" is reserved for those entities that are currently not otherwise classified. Using FIGO System 1 as a gateway to FIGO System 2 streamlines the investigation of reproductive-aged women and girls with AUB. Understanding the pathogenesis of the FIGO System 2 "PALM-COEIN" causes helps interpret investigations and the onward management of AUB. Numerous evidence gaps exist concerning AUB; however, if researchers and trialists universally adopt FIGO Systems 1 and 2 for the assessment and diagnosis of AUB, clear translatable research findings can be applied globally.

Puzzling Out the Genetic Architecture of Endometriosis: Whole-Exome Sequencing and Novel Candidate Gene Identification in a Deeply Clinically Characterised Cohort

Endometriosis (EM) is a common multifactorial gynaecological disorder. Although Genome-Wide Association Studies have largely been employed, the current knowledge of the genetic mechanisms underlying EM is far from complete, and other approaches are needed. To this purpose, whole-exome sequencing (WES) was performed on a deeply characterised cohort of 80 EM patients aimed at the identification of rare and damaging variants within 46 EM-associated genes and novel candidates. WES analysis detected 63 rare, predicted, and damaging heterozygous variants within 24 genes in 63% of the EM patients. In particular, (1) a total of 43% of patients carried variants within 13 recurrent genes (FCRL3, LAMA5, SYNE1, SYNE2, GREB1, MAP3K4, C3, MMP3, MMP9, TYK2, VEGFA, VEZT, RHOJ); (2) a total of 8.8% carried private variants within eight genes (KAZN, IL18, WT1, CYP19A1, IL1A, IL2RB, LILRB2, ZNF366); (3) a total of 24% carried variants within three novel candidates (ABCA13, NEB, CSMD1). Finally, to deepen the polygenic architecture of EM, a comprehensive evaluation of the analysed genes was performed, revealing a higher burden (p < 0.05) of genes harbouring rare and damaging variants in the EM patients than in the controls. These results highlight new insights into EM genetics, allowing for the definition of novel genotype-phenotype correlations, thereby contributing, in a long-term perspective, to the development of personalised care for EM patients.

Magnetic resonance imaging presentation of diffuse and focal adenomyosis before and after pregnancy

RESEARCH QUESTION

Is there a change in magnetic resonance imaging (MRI) criteria of diffuse and focal phenotypes of adenomyosis before and after pregnancy?

DESIGN

A retrospective, monocentric, observational study in a single academic tertiary referral centre for endometriosis diagnosis and management. Women were followed for symptomatic adenomyosis, and without a prior history of surgery who give birth after 24+0 weeks. For each patient, pelvic MRI pre- and post-pregnancy was performed by two experienced radiologists with the same image acquisition protocol. Diffuse and focal adenomyosis MRI presentation were analysed before and after pregnancy.

RESULTS

Between January 2010 and September 2020, of the 139 patients analysed, 96 (69.1%) had adenomyosis at MRI distributed as follow: 22 (15.8%) presented diffuse adenomyosis, 55 (39.6%) focal adenomyosis and 19 (13.7%) both phenotypes. The frequency of isolated diffuse adenomyosis on MRI was significantly lower before versus after pregnancy (n = 22 [15.8%] versus n = 41 [29.5%], P = 0.01). The frequency of isolated focal adenomyosis was significantly higher before pregnancy than after pregnancy (n = 55 [39.6%] versus n = 34 [24.5%], P = 0.01). The mean volume of all focal adenomyosis lesions on MRI decreased significantly after pregnancy, from 6.7 ± 2.5 mm3 to 6.4 ± 2.3 mm3, P = 0.01.

CONCLUSION

The current data indicate that, based on MRI, there is an increase in diffuse adenomyosis and a decrease in focal adenomyosis after pregnancy.

Prevalence of adenomyosis in women with subfertility: systematic review and meta-analysis

OBJECTIVE

To determine the prevalence of adenomyosis in women with subfertility.

METHODS

A systematic search was conducted in MEDLINE, EMBASE, CINAHL Plus, Google Scholar, PsycINFO and Web of Science Core Collection from database inception to October 2022. The included studies evaluated the prevalence of adenomyosis in women with subfertility, with or without endometriosis and/or uterine fibroids. Secondary analyses were conducted to identify variation in the prevalence of isolated adenomyosis according to geographical location, diagnostic modality, diagnostic criteria, type of ultrasound, ultrasound features of adenomyosis and the use of assisted reproductive technology.

RESULTS

Among 21 longitudinal studies evaluating 25 600 women, the overall pooled prevalence of isolated adenomyosis was 10% (95% CI, 6-15%) (I2  = 99.1%; tau2  = 0.12). The pooled prevalence was 1% (95% CI, 0-4%) for adenomyosis with concurrent fibroids (eight studies; I2  = 95.8%; tau2  = 0.03), 6% (95% CI, 3-11%) for adenomyosis with concurrent endometriosis (18 studies; I2  = 98.6%; tau2  = 0.12) and 7% (95% CI, 2-13%) for adenomyosis with concurrent endometriosis and/or fibroids (nine studies; I2  = 98.3%; tau2  = 0.09). The prevalence of isolated adenomyosis varied substantially according to geographical location, with Australia exhibiting the highest pooled prevalence of adenomyosis (19% (95% CI, 12-27%)), which was significantly higher compared with that in Asia (5% (95% CI, 1-12%)). The pooled prevalence of isolated adenomyosis diagnosed using a combination of direct and indirect ultrasound features was 11% (95% CI, 7-16%), whereas it was 0.45% (95% CI, 0-1%) in the study in which only an indirect feature was used as the diagnostic criterion.

CONCLUSION

One in 10 women with subfertility have a diagnosis of isolated adenomyosis. The prevalence of adenomyosis varies according to the presence of concurrent endometriosis and/or fibroids. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The ADENO study: ADenomyosis and its Effect on Neonatal and Obstetric outcomes: a retrospective population-based study

BACKGROUND

Adenomyosis is a benign gynecologic condition arising from the uterine junctional zone. Recent studies suggest a relationship between adenomyosis and adverse obstetrical outcomes, but evidence remains conflicting. There is no large-scale study investigating obstetrical outcomes in women with adenomyosis using the gold standard of histopathologic diagnosis.

OBJECTIVE

This study aimed to investigate the prevalence of adverse obstetrical and neonatal outcomes in women with histopathologic adenomyosis and that of the general (Dutch) population.

STUDY DESIGN

This retrospective population-based study used 2 Dutch national databases (Perined, the perinatal registry, and the nationwide pathology databank [Pathologisch Anatomisch Landelijk Geautomiseerd Archief], from 1995 to 2018) to compare obstetrical outcomes in women before histopathologic adenomyosis diagnosis to the general Dutch population without registered histopathologic adenomyosis. The adjusted odds ratios (95% confidence interval) were calculated for adverse obstetrical outcomes. The outcomes were adjusted for maternal age, parity, ethnicity, year of registered birth, induction of labor, hypertensive disorders in previous pregnancies, multiple gestation, and low socioeconomic status.

RESULTS

The pregnancy outcomes of 7925 women with histopathologic adenomyosis were compared with that of 4,615,803 women without registered adenomyosis. When adjusted for confounders, women with adenomyosis had adjusted odds ratios of 1.37 (95% confidence interval, 1.25-1.50) for hypertensive disorders, 1.37 (95% confidence interval, 1.25-1.51) for preeclampsia, 1.15 (95% confidence interval, 1.07-1.25) for small-for-gestational-age infants, 1.54 (95% confidence interval, 1.41-1.68) for emergency cesarean delivery, 1.24 (95% confidence interval, 1.12-1.37) for failure to progress, 1.29 (95% confidence interval, 1.10-1.48) for placental retention, and 1.23 (95% confidence interval, 1.10-1.38) for postpartum hemorrhage. No increased risk of HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome, placental abruption, or operative vaginal delivery or need for oxytocin stimulation was found.

CONCLUSION

Women with a histopathologic diagnosis of adenomyosis showed an increased prevalence of hypertensive disorders of pregnancy and small-for-gestational-age infants, failure to progress in labor, and placental retention compared with the general population in previous pregnancies. This suggests that uterine (contractile) function in labor and during pregnancy is impaired in women with adenomyosis.

An Appraisal of the Tissue Injury and Repair (TIAR) Theory on the Pathogenesis of Endometriosis and Adenomyosis

As understanding their pathogenesis remains elusive, both endometriosis and adenomyosis are often referred to as "enigmatic diseases". The uncertainty and heightened interest are reflected in the range of expressed views and opinions. There is a sense of urgency because of the entailed patient suffering. The plethora of opinions calls for a critical analysis of proposed theories, both old and new. A series of papers published since 2009 proposed that both endometriosis and adenomyosis originate from the same aberrations occurring within the uterus. This came to be recognized as the tissue injury and repair theory, and the newly coined term "archimetrosis" posits that the two diseases share the same origin. While the theory opens an interesting channel for exploration, its claim as a unifying theory necessitates a critical appraisal. We, thus, undertook this review of the theory and analyzed its underpinnings based on a comprehensive review of the literature. Our appraisal indicates that the theory is open to a range of criticisms. Chief among these is the need for confirmatory evidence of features of abnormal uterine contractility and the lack of data addressing the question of causality. In addition, the theory has, as yet, no supporting epidemiological evidence, which is a major weakness. The theory suffers as it is not open to the test of falsifiability, and it lacks the ability to make useful predictions. It has not addressed the questions, such as why only a small percentage of women develop adenomyosis or endometriosis, given the ubiquity of uterine peristalsis. On the other hand, the triggers and prevention of hyper- or dys-peristalsis become critical to a theory of causation. We conclude that additional supportive evidence is required for the theory to be accepted.

Cannabis smoking, tobacco cigarette smoking, and adenomyosis risk

OBJECTIVE

To investigate cannabis smoking and tobacco cigarette smoking in relation to adenomyosis risk.

DESIGN

We used data from a case-control study of adenomyosis conducted among enrollees ages 18-59 years of an integrated health care system in Washington State. The case-control study used 2 control groups given the challenge of selecting noncases when cases are diagnosed by hysterectomy.

SUBJECTS

Cases (n = 386) were enrollees with incident, pathology-confirmed adenomyosis diagnosed between April 1, 2001, and March 31, 2006. The 2 control groups comprised hysterectomy controls (n = 233) with pathology-confirmed absence of adenomyosis and population controls (n = 323) with an intact uterus selected randomly from the health care system population and frequency matched to cases on age.

EXPOSURE

Detailed data on cannabis and tobacco cigarette smoking history were ascertained through in-person structured interviews, allowing estimation of joint-years of cannabis smoking and pack-years of tobacco cigarette smoking.

MAIN OUTCOME MEASURES

Odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between cannabis smoking, tobacco cigarette smoking, and adenomyosis were estimated using multivariable unconditional logistic regression. Analyses were adjusted for age, reference year, menarche age, education, and pack-years of cigarette smoking (or joint-years of cannabis smoking).

RESULTS

No association was observed between cannabis smoking history and adenomyosis risk. However, we did observe the suggestion of an association between ever tobacco cigarette smoking and adenomyosis risk, comparing cases to hysterectomy controls (OR, 1.3; 95% CI, 0.9-1.9) and population controls (OR, 1.2; 95% CI, 0.8-1.8). Our data suggested a 50% increased odds of adenomyosis with >15 pack-years of smoking (vs. never smoking), comparing cases to hysterectomy controls (OR, 1.5; 95% CI, 0.9-2.6; Ptrend=.135). The suggestion of a 40% increased adenomyosis odds was observed with smoking >5-15 pack-years (vs. never smoking), comparing cases to population controls (OR, 1.4; 95% CI, 0.8-2.4; Ptrend=0.136).

CONCLUSION

In the first study of cannabis smoking and adenomyosis risk, no association was observed. However, our data suggested an increased odds of adenomyosis with history of tobacco cigarette smoking. Further research is warranted to replicate our results given the substantial morbidity with adenomyosis and frequency of cigarette smoking and recreational and medical cannabis use.

Adenomyosis: single-cell transcriptomic analysis reveals a paracrine mesenchymal-epithelial interaction involving the WNT/SFRP pathway

OBJECTIVE

To assess the cellular and molecular landscape of adenomyosis.

DESIGN

Single-cell analysis of genome-wide messenger RNA (mRNA) expression (single-cell RNA sequencing) of matched tissues of endometrium, adenomyosis, and myometrium using relatively large numbers of viable cells.

SETTING

Not applicable.

PATIENT(S)

Patients (n = 3, age range 40-44 years) undergoing hysterectomy for diffuse adenomyosis.

MAIN OUTCOME MEASURE(S)

Definition of the molecular landscape of matched adenomyotic, endometrial and myometrial tissues from the same uterus using single-cell RNA sequencing and comparison of distinct cell types in these tissues to identify disease-specific cell populations, abnormal gene expression and pathway activation, and mesenchymal-epithelial interactions.

RESULT(S)

The largest cell population in the endometrium was composed of closely clustered fibroblast groups, which comprise 36% of all cells and seem to originate from pericyte progenitors differentiating to estrogen/progesterone receptor-expressing endometrial stromal- cells. In contrast, the entire fibroblast population in adenomyosis comprised a larger (50%) portion of all cells and was not linked to any pericyte progenitors. Adenomyotic fibroblasts eventually differentiate into extracellular matrix protein-expressing fibroblasts and smooth muscle cells. Hierarchical clustering of mRNA expression revealed a unique adenomyotic fibroblast population that clustered transcriptomically with endometrial fibroblasts, suggestive of an endometrial stromal cell population serving as progenitors of adenomyosis. Four other adenomyotic fibroblast clusters with disease-specific transcriptomes were distinct from those of endometrial or myometrial fibroblasts. The mRNA levels of the natural WNT inhibitors, named, secreted frizzled-related proteins 1, 2, and 4, were higher in these 4 adenomyotic fibroblast clusters than in endometrial fibroblast clusters. Moreover, we found that multiple WNTs, which originate from fibroblasts and target ciliated and unciliated epithelial cells and endothelial cells, constitute a critical paracrine signaling network in adenomyotic tissue. Compared with endometrial tissue, unciliated and ciliated epithelial cells in adenomyosis comprised a significantly smaller portion of this tissue and exhibited molecular evidence of progesterone resistance and diminished regulation of estrogen signaling.

CONCLUSION(S)

We found a high degree of heterogeneity in fibroblast-like cells in the adenomyotic uterus. The WNT signaling involving differential expression of secreted frizzled-related proteins, which act as decoy receptors for WNTs, in adenomyotic fibroblasts may have a key role in the pathophysiology of this disease.

A Lifelong Impact on Endometriosis: Pathophysiology and Pharmacological Treatment

Endometriosis is a chronic inflammatory disease associated with bothersome symptoms in premenopausal women and is complicated with long-term systemic impacts in the post-menopausal stage. It is generally defined by the presence of endometrial-like tissue outside the uterine cavity, which causes menstrual disorders, chronic pelvic pain, and infertility. Endometriotic lesions can also spread and grow in extra-pelvic sites; the chronic inflammatory status can cause systemic effects, including metabolic disorder, immune dysregulation, and cardiovascular diseases. The uncertain etiologies of endometriosis and their diverse presentations limit the treatment efficacy. High recurrence risk and intolerable side effects result in poor compliance. Current studies for endometriosis have paid attention to the advances in hormonal, neurological, and immunological approaches to the pathophysiology and their potential pharmacological intervention. Here we provide an overview of the lifelong impacts of endometriosis and summarize the updated consensus on therapeutic strategies.

Characterising the immune cell phenotype of ectopic adenomyosis lesions compared with eutopic endometrium: A systematic review

Inflammation is implicated in the symptomatology and the pathogenesis of adenomyosis. Injury at the endo-myometrial interface causes inflammation and may facilitate the invasion of endometrium into the myometrium, forming adenomyosis lesions. Their presence causes local inflammation, resulting in heavy menstrual bleeding, chronic pelvic pain, and subfertility. Immunological differences have been described in the eutopic endometrium from women with adenomyosis compared to healthy endometrium, and differences are also expected in the adenomyotic lesions compared with the correctly sited eutopic endometrium. This systematic review retrieved relevant articles from three databases with additional manual citation chaining from inception to 24th October 2022. Twenty-two eligible studies were selected in accordance with PRISMA guidelines. Risk of bias assessments were performed, and the findings presented thematically. Ectopic endometrial stroma contained an increased density of macrophages compared with eutopic endometrium in adenomyosis. This was associated with an increase in pro-inflammatory cytokines (IL-6, IL-8, ILβ-1, C-X-C Motif Chemokine Receptor 1(CXCR1), Monocyte Chemoattractant Protein-1 (MCP-1)), and an imbalance of anti-inflammatory cytokines (IL-22, IL-37). Cells in ectopic lesions also contained a higher levels of toll-like receptors and immune-mediated enzymes. However, the studies were heterogeneous, with inconsistent reporting of immune cell density within epithelial or stromal compartments, and inclusion of samples from different menstrual cycle phases in the same group for analysis. A detailed understanding of the immune cell phenotypes present in eutopic and ectopic endometrium in adenomyosis and associated dysregulated inflammatory processes will provide further insight into the pathogenesis, to enable identification of fertility-sparing treatments as an alternative to hysterectomy.

Molecular Targets for Nonhormonal Treatment Based on a Multistep Process of Adenomyosis Development

Adenomyosis is an estrogen-dependent gynecologic disease characterized by the presence of endometrial tissue within the myometrium. Adenomyosis presents with abnormal uterine bleeding, pelvic pains, and infertility. This review aimed to investigate the major estrogen downstream effectors involved in the process of adenomyosis development and their potential use for nonhormonal treatment. A literature search was performed for preclinical and clinical studies published between January 2010 and November 2021 in the PubMed and Google Scholar databases using a combination of specific terms. Adenomyosis presents with a wide spectrum of clinical manifestations from asymptomatic to severe through a complex process involving a series of molecular changes associated with inflammation, invasion, angiogenesis, and fibrosis. Adenomyosis may develop through a multistep process, including the acquisition of (epi)genetic mutations, tissue injury caused at the endometrial-myometrial interface, inside-to-outside invasion (from the endometrial side into the uterine wall), or outside-to-inside invasion (from the serosal side into the uterine wall), and epithelial-mesenchymal transition, tissue repair or remodeling in the myometrium. These processes can be regulated by increased estrogen biosynthesis and progesterone resistance. The expression of estrogen downstream effectors associated with persistent inflammation, fragile and more permeable vessel formation, and tissue injury and remodeling may be correlated with dysmenorrhea, heavy menstrual bleeding, and infertility, respectively. Key estrogen downstream targets (e.g., WNT/β-catenin, transforming growth factor-β, and nuclear factor-κB) may serve as hub genes. We reviewed the molecular mechanisms underlying the development of adenomyosis and summarized potential nonhormonal therapies.

Endometrial Inflammation and Impaired Spontaneous Decidualization: Insights into the Pathogenesis of Adenomyosis

Adenomyosis is an estrogen-dependent gynecologic disease characterized by the myometrial invasion of the endometrial tissue. This review summarized the current understanding and recent findings on the pathophysiology of adenomyosis, focusing on repeated menstruation, persistent inflammation, and impaired spontaneous decidualization. A literature search was performed in the PubMed and Google Scholar databases from inception to 30 April 2022. Thirty-one full-text articles met the eligibility criteria. Repeated episodes of physiological events (i.e., endometrial shedding, damage, proliferation, differentiation, repair, and regeneration) during the menstrual cycle are associated with inflammation, angiogenesis, and immune processes. The decidualization process in humans is driven by the rise in progesterone levels, independently of pregnancy (i.e., spontaneous decidualization). Adenomyotic cells produce angiogenic and fibrogenic factors with the downregulation of decidualization-associated molecules. This decidualization dysfunction and persistent inflammation are closely related to the pathogenesis of adenomyosis. Recently, it has been found that the reproductive tract microbiota composition and function in women with adenomyosis differ from those without. An increase in opportunistic pathogens and a decrease in beneficial commensals may promote impaired defense mechanisms against inflammation and predispose women to uncontrolled endometrial inflammation. However, currently, there is no direct evidence that adenomyosis is linked to pre-existing inflammation and impaired spontaneous decidualization. Overall, persistent inflammation, impaired spontaneous decidualization, and microbiota dysbiosis (i.e., an imbalance in the composition and function of endometrial microbiota) may be involved in the pathophysiology of adenomyosis.

The Role of Platelets in the Pathogenesis and Pathophysiology of Adenomyosis

Widely viewed as an enigmatic disease, adenomyosis is a common gynecological disease with bewildering pathogenesis and pathophysiology. One defining hallmark of adenomyotic lesions is cyclic bleeding as in eutopic endometrium, yet bleeding is a quintessential trademark of tissue injury, which is invariably followed by tissue repair. Consequently, adenomyotic lesions resemble wounds. Following each bleeding episode, adenomyotic lesions undergo tissue repair, and, as such, platelets are the first responder that heralds the subsequent tissue repair. This repeated tissue injury and repair (ReTIAR) would elicit several key molecular events crucial for lesional progression, eventually leading to lesional fibrosis. Platelets interact with adenomyotic cells and actively participate in these events, promoting the lesional progression and fibrogenesis. Lesional fibrosis may also be propagated into their neighboring endometrial-myometrial interface and then to eutopic endometrium, impairing endometrial repair and causing heavy menstrual bleeding. Moreover, lesional progression may result in hyperinnervation and an enlarged uterus. In this review, the role of platelets in the pathogenesis, progression, and pathophysiology is reviewed, along with the therapeutic implication. In addition, I shall demonstrate how the notion of ReTIAR provides a much needed framework to tether to and piece together many seemingly unrelated findings and how it helps to make useful predictions.

M2 macrophages enhance endometrial cell invasiveness by promoting collective cell migration in uterine adenomyosis

RESEARCH QUESTION

Are M2 macrophages implicated in endometrial invasiveness in adenomyosis?

DESIGN

Seventeen formalin-fixed paraffin-embedded uterine samples and 16 fresh endometrial biopsies were collected from women with or without adenomyosis. Double immunofluorescence was performed to determine the predominant macrophage population in adenomyosis between M1 and M2 phenotypes. The invasion capacity of endometrial cells was assessed by invasion assays and quantitative polymerase chain reaction for genes involved in cell motility and epithelial-mesenchymal transition (EMT). Specific mechanisms of invasion were investigated by immunohistochemistry for E-cadherin, N-cadherin and matrix metalloproteinase 9 (MMP9).

RESULTS

Only M2 macrophages were found to accumulate in adenomyosis, in higher numbers in both eutopic endometrium (P = 0.0109) and lesions (P = 0.0267) than healthy tissue. Co-culture with M2 macrophages significantly boosted invasion capacity in endometrial epithelial (P = 0.0002; P = 0.002) and stromal cells (P = 0.0469; P = 0.0047) from both adenomyosis patients and healthy controls. No gene expression differences indicating EMT were noted, either between co-cultured and control cells, or between healthy and adenomyotic cells. E- and N-cadherin protein expression did not differ significantly between endometrium from adenomyosis subjects and healthy tissue but MMP9 expression was increased in eutopic stroma from adenomyosis patients (P = 0.0492). In adenomyosis, both E-cadherin (P = 0.0379) and N-cadherin (P = 0.0196) were more extensively expressed in basal glands than functional glands.

CONCLUSIONS

M2 macrophages accumulate in adenomyosis and enhance invasion capacity of adenomyotic and even healthy endometrial cells, implying that macrophage infiltration alone may be sufficient to promote the disease. This study failed to detect any changes pointing to EMT, suggesting an alternative mode of invasion. Strong E- and N-cadherin-positive intercellular junctions in basal (invasive) glands suggest the involvement of collective cell migration in the invasion process of endometrium.

Reproductive outcome in 326 women with unicornuate uterus

OBJECTIVES

To study the reproductive outcomes of women with a unicornuate uterus and compare them to those of women with no congenital uterine anomaly.

METHODS

This was a single-center, retrospective cohort study. Cases were women aged at least 16 years who were diagnosed with a unicornuate uterus on transvaginal/transrectal ultrasound between January 2008 and September 2021. Controls were women with no congenital uterine anomaly matched 1:1 by age and body mass index. The primary outcome was live-birth rate. Secondary outcomes were pregnancy loss (miscarriage, ectopic pregnancy, termination of pregnancy), preterm delivery, mode of delivery and concomitant gynecological abnormalities (endometriosis, adenomyosis, fibroids).

RESULTS

Included in the study were 326 cases and 326 controls. Women with a unicornuate uterus had a significantly lower live-birth rate (184/388 (47.4%) vs 229/396 (57.8%); P = 0.004) and higher rates of overall miscarriage (178/424 (42.0%) vs 155/465 (33.3%); adjusted odds ratio (aOR), 2.21 (95% CI, 1.42-3.42), P < 0.001), ectopic pregnancy (26/424 (6.1%) vs 11/465 (2.4%); aOR, 2.52 (95% CI, 1.22-5.22), P = 0.01), preterm delivery (45/184 (24.5%) vs 17/229 (7.4%); aOR, 3.04 (95% CI, 1.52-5.97), P = 0.001) and Cesarean delivery (116/184 (63.0%) vs 70/229 (30.6%); aOR, 2.54 (95% CI, 1.67-3.88), P < 0.001). Rudimentary-horn pregnancies accounted for 7/26 (26.9%) ectopic pregnancies in the study group. Women with a unicornuate uterus were more likely to have endometriosis (17.5% vs 10.7%; P = 0.018) and adenomyosis (26.7% vs 15.6%; P = 0.001), but were not more likely to have fibroids compared with controls. Women with a functional rudimentary horn were more likely to have pelvic endometriosis compared to those without (odds ratio, 2.4 (95% CI, 1.4-4.1), P = 0.002).

CONCLUSIONS

Pregnant women with a unicornuate uterus should be classified as high risk. Removal of a functional rudimentary horn should be discussed with the patient to prevent a rudimentary-horn ectopic pregnancy. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Archimetrosis: the evolution of a disease and its extant presentation : Pathogenesis and pathophysiology of archimetrosis (uterine adenomyosis and endometriosis)

PURPOSE

This article presents a novel concept of the evolution and, thus, the pathogenesis of uterine adenomyosis as well as peritoneal and peripheral endometriosis. Presently, no unifying denomination of this nosological entity exists.

METHODS

An extensive search of the literature on primate evolution was performed. This included comparative functional morphology with special focus on the evolution of the birthing process that fundamentally differs between the haplorrhine primates and most of the other eutherian mammals. The data were correlated with the results of own research on the pathophysiology of human archimetrosis and with the extant presentation of the disease.

RESULTS

The term Archimetrosis is suggested as a denomination of the nosological entity. Archimetrosis occurs in human females and also in subhuman primates. There are common features in the reproductive process of haplorrhine primates such as spontaneous ovulation and corpus luteum formation, spontaneous decidualization and menstruation. These have fused Müllerian ducts resulting in a uterus simplex. Following a usually singleton pregnancy, the fetus is delivered in the skull position. Some of these features are shared by other mammals, but not in that simultaneous fashion. In haplorrhine primates, with the stratum vasculare, a new myometrial layer has evolved during the time of the Cretaceous-Terrestrial Revolution (KTR) that subserves expulsion of the conceptus and externalization of menstrual debris in non-conceptive cycles. Hypercontractility of this layer has evolved as an advantage with respect to the survival of the mother and the birth of a living child during delivery and may be experienced as primary dysmenorrhea during menstruation. It may result in tissue injury by the sheer power of the contractions and possibly by the associated uterine ischemia. Moreover, the lesions at extra-uterine sites appear to be maintained by biomechanical stress.

CONCLUSIONS

Since the pathogenesis of archimetrosis is connected with the evolution of the stratum vasculare, tissue injury and repair (TIAR) turns out to be the most parsimonious explanation for the development of the disease based on clinical, experimental and evolutionary evidence. Furthermore, a careful analysis of the published clinical data suggests that, in the risk population with uterine hypercontractility, the disease develops with a yet to be defined latency phase after the onset of the biomechanical injury. This opens a new avenue of prevention of the disease in potentially affected women that we consider to be primarily highly fertile.

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.

Osteopontin Splicing Isoforms Contribute to Endometriotic Proliferation, Migration, and Epithelial-Mesenchymal Transition in Endometrial Epithelial Cells

Osteopontin (OPN) isoforms, including OPNb and OPNc, promote malignancy and may contribute to the pathogenesis of endometriosis, a benign disorder with multiple characteristics resembling malignant tumors. In our experiments, OPNb and OPNc were significantly overexpressed in both endometriosis and adenomyosis compared to the normal endometrium. Upregulation of CD44v and the epithelial-mesenchymal transition (EMT) process was also present in endometriotic lesions. Overexpression of OPNb and OPNc splicing variants in endometriotic cells evoked morphological changes, actin remodeling, cell proliferation, cell migration, and EMT through binding OPN ligand receptors CD44 and αvβ3, subsequently activating the PI3K and NF-ĸB pathways. We elucidated the causal role of OPN splice variants in regulating endometriotic cell growth, which may promote the development of OPN-targeted therapies for patients suffering from endometriotic disorders.

RNA-seq reveals co-dysregulated circular RNAs in the adenomyosis eutopic endometrium and endometrial–myometrial interface

Background

Uterine adenomyosis is associated with chronic pelvic pain, abnormal uterine bleeding, and infertility. The pathogenesis of adenomyosis is still unclear. Circular RNAs (circRNAs) have been implicated in several benign diseases and malignant tumors. We aimed to explore the co-dysregulated circular RNA profile in the eutopic endometrium and endometrial–myometrial interface (EMI) of adenomyosis.

Methods

Total RNA was extracted from the eutopic endometrium and EMI of 5 patients with adenomyosis and 3 patients without adenomyosis. Next-generation sequencing was performed to identify the circRNA expression profile of the two tissue types. Bioinformatics analysis was performed to predict circRNA-binding miRNAs and miRNA-binding mRNAs and construct ceRNA networks, and functional enrichment analysis was performed to predict the biological functions of circRNAs.

Results

Among the adenomyosis patients, 760 circRNAs were significantly upregulated and 119 circRNAs were significantly downregulated in the EMI of adenomyosis, while 47 circRNAs were significantly upregulated and 17 circRNAs were significantly downregulated in the eutopic endometrium of adenomyosis. We identified hsa_circ_0002144 and hsa_circ_0005806 as co-upregulated and hsa_circ_0079536 and hsa_circ_0024766 as co-downregulated in the eutopic endometrium and EMI. Bioinformatics analysis was performed to construct a ceRNA network of codifferentially expressed circRNAs. The MAPK signaling pathway is the most important signaling pathway involved in the function of the ceRNA network.

Conclusions

Co-dysregulated circRNAs were present in the eutopic endometrium and EMI of adenomyosis. MiRNA binding sites were observed for all of these circRNAs and found to regulate gene expression. Co-dysregulated circRNAs may induce the eutopic endometrial invagination process through the MAPK signaling pathway and promote the progression of adenomyosis.

Laparoscopic Adenomyomectomy under Real-Time Intraoperative Ultrasound Elastography Guidance: A Case Series and Feasibility Study

BACKGROUND

This study aimed to examine the clinical characteristics of 11 patients undergoing laparoscopic adenomyomectomy guided by intraoperative ultrasound elastography and this technique's feasibility.

PATIENTS AND METHODS

Eleven patients undergoing laparoscopic adenomyomectomy using ultrasound elastography for adenomyosis at Kawasaki Medical School Hospital in Okayama, Japan between March 2020 and February 2021 were enrolled. Operative outcomes included operative time, operative bleeding, resected weight, operation complications, percent change in hemoglobin (Hb) values, and uterine volume pre- and postoperatively. Dysmenorrhea improvement was evaluated by changes in visual analog scale (VAS) scores pre- and 6- and 12-months postoperatively.

RESULTS

The median operative time and bleeding volume was 125 min (range, 88-188 min) and 150 mL (10-450 mL), respectively. The median resected weight was 5.0 g (1.5-180 g). No intraoperative or postoperative blood transfusions or perioperative complications were observed. The median changes in uterine volume, Hb value, and VAS score were -49% (-65 to -28%), -3% (-11 to 35%), and -80% (-100 to -50%), respectively. The median follow-up period post-surgery was 14 months (7-30 months). Adenomyosis recurrence was not observed in the patients during the follow-up period.

CONCLUSIONS

Laparoscopic adenomyomectomy using ultrasound elastography guidance is minimally invasive and resects as many adenomyotic lesions as possible.

Cracking the enigma of adenomyosis: an update on its pathogenesis and pathophysiology

In brief

Traditionally viewed as enigmatic and elusive, adenomyosis is a fairly common gynecological disease but is under-recognized and under-researched. This review summarizes the latest development on the pathogenesis and pathophysiology of adenomyosis, which have important implications for imaging diagnosis of the disease and for the development of non-hormonal therapeutics.

Abstract

Traditionally considered as an enigmatic disease, adenomyosis is a uterine disease that affects many women of reproductive age and is a contributing factor for pelvic pain, heavy menstrual bleeding (HMB), and subfertility. In this review, the new development in the pathogenesis and pathophysiology of adenomyosis has been summarized, along with their clinical implications. After reviewing the progress in our understanding of the pathogenesis and describing the prevailing theories, in conjunction with their deficiencies, a new hypothesis, called endometrial-myometrial interface disruption (EMID), which is backed by extensive epidemiologic data and demonstrated by a mouse model, is reviewed, along with recent data implicating the role of Schwann cells in the EMI area in the genesis of adenomyosis. Additionally, the natural history of adenomyotic lesions is elaborated and underscores that, in essence, adenomyotic lesions are fundamentally wounds undergoing repeated tissue injury and repair (ReTIAR), which progress to fibrosis through epithelial-mesenchymal transition, fibroblast-to-myofibroblast transdifferentiation, and smooth muscle metaplasia. Increasing lesional fibrosis propagates into the neighboring EMI and endometrium. The increased endometrial fibrosis, with ensuing greater tissue stiffness, results in attenuated prostaglandin E2, hypoxia signaling and glycolysis, impairing endometrial repair and causing HMB. Compared with adenomyosis-associated HMB, the mechanisms underlying adenomyosis-associated pain are less understood but presumably involve increased uterine contractility, hyperinnervation, increased lesional production of pain mediators, and central sensitization. Viewed through the prism of ReTIAR, a new imaging technique can be used to diagnose adenomyosis more accurately and informatively and possibly help to choose the best treatment modality.

Clinical efficacy of myometrial and endometrial microwave ablation in the treatment of patients with adenomyosis who had anemia

OBJECTIVE

This study evaluated the clinical efficacy of myometrial and endometrial microwave ablation (MEWA) for treating adenomyosis in patients with anemia.

METHODS

This retrospective study enrolled 64 patients with adenomyosis who had anemia treated with either MEWA (MEWA group) or myometrial microwave ablation (MMWA group) between May 2019 and May 2021. The uterine volumes, uterine-volume reduction rates, hemoglobin (Hb) levels, cancer antigen 125 (CA125) levels, dysmenorrhea visual analog scale (VAS) scores, uterine fibroblast symptoms and health-related quality of life (UFS-QOL) scores, menstrual flow scores (MFS) before and 3, 6, and 12 months post-treatment, and adverse events and complications in both groups were collected to assess clinical efficacy.

RESULTS

No statistically significant preoperative differences were observed in any measured factors. Postoperatively, there was a significant reduction in uterine volume and CA125 level, an increase in Hb level, and improvement in the UFS-QOL, dysmenorrhea VAS score, and MFS. No differences were observed in postoperative uterine volume, CA125 level, overall response rate, and adverse event rate during the follow-up period until 12 months postoperatively. However, the MEWA group showed a better uterine-volume reduction rate 6 months postoperatively and improvement in Hb level, USF-QOL score, dysmenorrhea VAS score, and MFS postoperatively.

CONCLUSION

MEWA and MMWA demonstrated high clinical efficacy in treating adenomyosis and anemia. However, MEWA is a more effective therapy that successfully improves anemia, resulting in improved quality of life.

Establishment of a novel mouse model of adenomyosis suitable for longitudinal and quantitative analysis and perinatal outcome studies

The purpose of this study was to establish a novel mouse model of adenomyosis suitable for longitudinal and quantitative analyses and perinatal outcome studies. Using a 30 G needle, the entire uterine wall of one horn was mechanically punctured at a frequency of 100 times/1 cm (adenomyosis horn). The other horn was left unpunctured (control horn). Balb/c mice were sacrificed on day 14 (D14) or day 65 (D65) (n = 3 each). The uterus was fixed, paraffin-embedded, sliced, and stained. Lesions were detected and counted, and their volumes were measured. Cell proliferation and fibrosis were assessed by Ki67 and Masson's Trichrome staining, respectively. Blood vessels were detected using CD31 immunostaining. Some of the mice (n = 4), were mated and the date of delivery, litter size, number of implantations, and number and volume of postpartum lesions were measured. The number of lesions per horn did not differ between D14 and D65. The volume of the entire lesion was significantly greater on D65 than on D14 (p < 0.0001). The volume of the epithelial part of the lesion was significantly greater in D65 (p < 0.0001). The volume of the stromal part of the lesion was also greater on D65 (p < 0.0001). The percentage of Ki67 positive cells in the epithelial part of the lesion was significantly higher on D14 (p < 0.05). In contrast, the percentage of Ki67-positive cells in the stromal part was significantly higher on D65 (p < 0.01). Vascular density in the lesions was higher in on D65 (p < 0.05). The percentage of fibrotic area was significantly higher on D65 (p < 0.01). The date of delivery was slightly earlier than that reported for healthy mice of the same strain. The litter size was smaller than that reported in previous research. The number of implantation sites did not differ between the control and the adenomyosis horn. The number and volume of lesions did not differ between the non-pregnant and postpartum groups. This model can be applied to evaluate the pathogenesis of adenomyosis, validate the efficacy of therapeutic agents, and evaluate the effect of adenomyosis on pregnancy and vice versa.

Cardiometabolic profiles in women with adenomyosis

The aim of this study was to investigate the reproductive profiles, metabolic parameters and cardiometabolic risk assessed by surrogate indexes in women with adenomyosis. Ninety-six premenopausal women who were diagnosed with adenomyosis by transvaginal ultrasound and 97 age-body mass index (BMI) matched controls with normal ultrasound during routine examination were included. Women with adenomyosis were more likely to have higher gravidity and had more abortions than women without adenomyosis. Regarding the individual metabolic syndrome components, the adenomyosis group was more likely to have higher prevalence of hypertension, low HDL-C and central obesity. No significant difference was found between the groups in terms of visceral adiposity index, lipid accumulation product and fatty liver index. Only higher blood pressure (BP) remained statistically significant after adjustment for confounding factors in multivariate analysis. Women with adenomyosis had remarkably high risk of hypertension. It may be advisable to monitor their BP closely.Impact StatementWhat is already known on this subject? The only anthropometric characteristic assessed in women in relation to adenomyosis is body mass index (BMI). A case-control study showed that women who are obese are more likely to have adenomyosis. The gravidity, number of spontaneous abortions and previous uterine surgeries such as dilatation and curettage (D&C) and caesarean section were found significantly associated with adenomyosis.What do the results of this study add? A remarkable finding of our study was the increased incidence of higher systolic BP in women with adenomyosis. No difference was observed in adiposity indices between women with and without adenomyosis. Higher prevalence of central obesity and lower HDL-C levels were seen in women with adenomyosis.What are the implications of these findings for clinical practice and/or further research? The study identifies that adenomyosis is associated with an increased risk of hypertension, and women with adenomyosis may be monitored closely for blood pressure changes. Our report also provides novel information about the metabolic risk profiles associated with adenomyosis.

Uterine disorders and iron deficiency anemia

Abnormal uterine bleeding (AUB) is a clinical entity which can lead to iron deficiency anemia. Classification according to the acronym PALM-COEIN (polyp, adenomyosis, leiomyoma, malignancy, and hyperplasia; coagulopathy, ovulatory dysfunction, endometrial, iatrogenic, and not otherwise classified) provides a structured approach to establish the cause of AUB. The goal of this review is to discuss the different mechanisms and the relationship between uterine disorders and AUB. Heavy menstrual bleeding, a subgroup of AUB, is more closely related to the presence of uterine fibroids. The relationship between heavy menstrual bleeding and uterine fibroids remains poorly characterized, particularly the understanding of endometrial function in women with structural myometrial features such as leiomyomas. A number of theories have been proposed in the literature and are discussed in this review. Uterine adenomyosis is also a frequent cause of AUB, and its pathogenesis is still far from being fully elucidated. The mechanisms contributing to its development are multifactorial. Many theories lean toward invasion of the myometrium by endometrial cells. Both clinical and basic studies favor the theory of direct invasion, although de novo development of adenomyosis from Müllerian rests or stem cells has not been ruled out. Development of adenomyotic lesions involves repeated tissue injury and repair. In addition, this review describes the other causes of AUB such as endometrial polyps, cesarean scar defects, and uterine vascular abnormalities. Endometrial polyps are often asymptomatic, but approximately 68% of women have concomitant AUB. Histologic alterations in the lower uterine segment in patients who had undergone cesarean sections were identified and may explain the cause of AUB.

Transcriptomic analysis supports collective endometrial cell migration in the pathogenesis of adenomyosis

RESEARCH QUESTION

Adenomyosis is a common uterine disorder of uncertain causes. Can transcriptomic analyses of the endometrium and myometrium reveal potential mechanisms underlying adenomyosis pathogenesis?

DESIGN

Transcriptomic profiles of eutopic endometrium and myometrium from women with and without diffuse adenomyosis and with symptomatic FIGO type 2-5 fibroids in the proliferative phase of the menstrual cycle were assessed using RNA sequencing and bioinformatic analysis. Differentially expressed genes (DEG) and potential pathways were validated by quantitative reverse transcription polymerase chain reaction, immunoblotting and Masson staining, using additional clinical samples.

RESULTS

Top biological processes in the endometrium of women with versus without adenomyosis, enriched from DEG, comprised inflammation, extracellular matrix (ECM) organization, collagen degradation and hyaluronan synthesis, which are key in cell migration and cell movement. Top biological processes enriched from DEG in the myometrium of women with versus without adenomyosis revealed ECM organization dysfunction, abnormal sensory pain perception and gamma aminobutyric acid (GABA) synaptic transmission. Dysregulation of prolactin signalling was also enriched in eutopic endometrium and in the myometrium of women with adenomyosis.

CONCLUSIONS

Overall, our results support the invasive endometrium theory in the pathogenesis of adenomyosis, in which inflammation induces ECM remodelling resulting in a track for subsequent endometrial collective cell migration and onset of adenomyosis. Moreover, abnormal myometrial GABA synaptic transmission may contribute to dysmenorrhoea in women with adenomyosis and is a possible target for novel therapeutic development. Prolactin signalling abnormalities may serve as another opportunity for therapeutic intervention.

Increased Angiogenesis and Lymphangiogenesis in Adenomyosis Visualized by Multiplex Immunohistochemistry

There is evidence for increased angiogenesis in the (ectopic) endometrium of adenomyosis patients under the influence of vascular endothelial growth factor (VEGF). VEGF stimulates both angiogenesis and lymph-angiogenesis. However, information on lymph vessels in the (ectopic) endometrium of adenomyosis patients is lacking. In this retrospective matched case-control study, multiplex immunohistochemistry was performed on thirty-eight paraffin embedded specimens from premenopausal women who had undergone a hysterectomy at the Amsterdam UMC between 2001 and 2018 to investigate the evidence for (lymph) angiogenesis in the (ectopic) endometrium or myometrium of patients with adenomyosis versus controls with unrelated pathologies. Baseline characteristics of both groups were comparable. In the proliferative phase, the blood and lymph vessel densities were, respectively, higher in the ectopic and eutopic endometrium of patients with adenomyosis than in the endometrium of controls. The relative number of blood vessels without α-smooth muscle actinin (α SMA) was higher in the eutopic and ectopic endometrium of adenomyosis patients versus controls. The level of VEGF staining intensity was highest in the myometrium but did not differ between patients with adenomyosis or controls. The results indicate increased angiogenesis and lymphangiogenesis in the (ectopic) endometrium affected by adenomyosis. The clinical relevance of our findings should be confirmed in prospective clinical studies.