Pathogenesis of Human Adenomyosis: Current Understanding and Its Association with Infertility

Prevalence and risk factors for chronic endometritis in patients with adenomyosis and infertility: a retrospective cohort study

BACKGROUND

To explore the incidence of chronic endometritis (CE) in patients with infertility and different forms of adenomyosis and analyze potential high-risk factors for infection.

METHODS

This retrospective cohort study included 154 patients with infertility in the Liuzhou Maternity and Child Healthcare Hospital. Among them, 77 patients with adenomyosis were divided into four subgroups based on magnetic resonance imaging (MRI): internal, exterior, intramural, and full-thickness. Meanwhile, 77 patients did not have adenomyosis. Hysteroscopy and endometrial biopsy were performed in the proliferative phase. The main outcome measures were the morphology of the endometrium, syndecan-1 (CD138) immunohistochemical staining, clinical characteristics, and prevalence of CE in the adenomyosis subgroups.

RESULTS

In comparison to the non-adenomyosis group, the adenomyosis group had significantly higher body mass index (BMI) and CA125 levels. The menstrual cycle in the adenomyosis group was significantly shorter, and menarche was significantly earlier. In comparison to the non-adenomyosis group, the adenomyosis group had a significantly higher diagnostic rate of CE (75.3% vs. 46.8% according to hysteroscopy and 74.0% vs. 33.8% according to histopathology, both with p < .050). The incidence of CE was significantly lower in patients with internal adenomyosis when compared with the other three subgroups. Increased BMI contributed to a higher risk of CE.

CONCLUSIONS

The prevalence of CE was significantly higher in patients with adenomyosis and infertility. The differences in the incidence of CE are closely associated with the classification of adenomyosis. When patients with infertility are diagnosed with adenomyosis, it is recommended to identify the subtype and screen for endometritis.

Hypoxia and the endometrium: An indispensable role for HIF-1α as therapeutic strategies

Hypoxia-inducible factor 1 alpha (HIF-1α) is a major molecular mediator of the hypoxic response. In the endometrium, local hypoxic conditions induced by hormonal fluctuations and endometrial vascular remodeling contribute to the production of HIF-1α, which plays an indispensable role in a series of physiological activities, such as menstruation and metamorphosis. The sensitive regulation of HIF-1α maintains the cellular viability and regenerative capacity of the endometrium against cellular stresses induced by hypoxia and excess reactive oxygen species. In contrast, abnormal HIF-1α levels exacerbate the development of various endometrial pathologies. This knowledge opens important possibilities for the development of promising HIF-1α-centered strategies to ameliorate endometrial disease. Nonetheless, additional efforts are required to elucidate the regulatory network of endometrial HIF-1α and promote the applications of HIF-1α-centered strategies in the human endometrium. Here, we summarize the role of the HIF-1α-mediated pathway in endometrial physiology and pathology, highlight the latest HIF-1α-centered strategies for treating endometrial diseases, and improve endometrial receptivity.

Bioengineering approaches for the endometrial research and application

The endometrium undergoes a series of precise monthly changes under the regulation of dynamic levels of ovarian hormones that are characterized by repeated shedding and subsequent regeneration without scarring. This provides the potential for wound healing during endometrial injuries. Bioengineering materials highlight the faithful replication of constitutive cells and the extracellular matrix that simulates the physical and biomechanical properties of the endometrium to a larger extent. Significant progress has been made in this field, and functional endometrial tissue bioengineering allows an in-depth investigation of regulatory factors for endometrial and myometrial defects in vitro and provides highly therapeutic methods to alleviate obstetric and gynecological complications. However, much remains to be learned about the latest progress in the application of bioengineering technologies to the human endometrium. Here, we summarize the existing developments in biomaterials and bioengineering models for endometrial regeneration and improving the female reproductive potential.

The pathogenesis of endometriosis and adenomyosis: insights from single-cell RNA sequencing†

Endometriosis and adenomyosis are two similar gynecological diseases that are characterized by ectopic implantation and the growth of the endometrial tissue. Previous studies have reported that they share a common pathophysiology in some respects, such as a similar cellular composition and resistance to the progestogen of lesions, but their underlying mechanisms remain elusive. Emerging single-cell ribonucleic acid sequencing (scRNA-seq) technologies allow for the dissection of single-cell transcriptome mapping to reveal the etiology of diseases at the level of the individual cell. In this review, we summarized the published findings in research on scRNA-seq regarding the cellular components and molecular profiles of diverse lesions. They show that epithelial cell clusters may be the vital progenitors of endometriosis and adenomyosis. Subclusters of stromal cells, such as endometrial mesenchymal stem cells and fibroblasts, are also involved in the occurrence of endometriosis and adenomyosis, respectively. Moreover, CD8+ T cells, natural killer cells, and macrophages exhibit a deficiency in clearing the ectopic endometrial cells in the immune microenvironment of endometriosis. It seems that the immune responses are activated in adenomyosis. Understanding the immune characteristics of adenomyosis still needs further exploration. Finally, we discuss the application of findings from scRNA-seq for clinical diagnosis and treatment. This review provides fresh insights into the pathogenesis of endometriosis and adenomyosis as well as the therapeutic targets at the cellular level.

The timing of adenomyosis diagnosis and its impact on pregnancy outcomes: a national population-based study

OBJECTIVE

Adenomyosis impacts pregnancy outcomes, although there is a lack of consensus regarding the actual effects. It is likely, however, that the severity of adenomyosis or ultrasound findings or timing of diagnosis can have different effects on adverse pregnancy outcomes (APOs).

METHODS

In this study, we aimed to investigate the impact of the timing of adenomyosis diagnosis on pregnancy outcomes. Singleton pregnant women who delivered between 2017 and 2022 were analyzed based on the timing of adenomyosis diagnosis, using a national database. The final cohort was classified into three groups: 1) group 1, without adenomyosis; 2) group 2, those diagnosed with adenomyosis before pregnancy; and 3) group 3, those diagnosed with adenomyosis during pregnancy.

RESULTS

A total of 1,226,475 cases were ultimately included in this study. Women with a diagnosis of adenomyosis had a significantly higher risk of APOs including hypertensive disorder during pregnancy (HDP), gestational diabetes mellitus (GDM), postpartum hemorrhage, placental abruption, preterm birth, and delivery of a small-for-gestational-age infant even after adjusting for covariates. In particular, concerning HDP, the risk was highest in group 3 (group 2: adjusted odds ratio [aOR], 1.15 vs. group 3: aOR, 1.36). However, the highest GDM risk was in group 2 (GDM; group 2: aOR, 1.24 vs. group 3: aOR, 1.04).

CONCLUSION

The increased risk of APO differed depending on the timing of adenomyosis diagnosis. Therefore, efforts for more careful monitoring and prevention of APOs may be necessary when such women become pregnant.

The Impact of Conservative Surgical Treatment of Adenomyosis on Fertility and Perinatal Outcomes

Adenomyosis is a benign condition commonly encountered in patients with infertility. While the definitive surgical management is hysterectomy, conservative surgical management is gaining attention in patients desiring future fertility. This review explores whether the surgical treatment of adenomyosis affects fertility outcomes for patients trying to conceive. The PubMed and Medline databases were searched using the keywords: "adenomyosis", "surgery", "radiofrequency", "infertility", "pregnancy", "sterility", "conception", "miscarriage", and "endometrial receptivity". Abstracts were screened, and relevant articles were selected for review. This review reveals that surgery appears to improve fertility outcomes with or without medical therapy; however, the risk of uterine rupture remains high and the best technique to reduce this risk is still not known. More studies are needed to formulate the best surgical approach for preserving fertility in treating adenomyosis and to establish standardized guidelines.

Association between Uterine Adenomyosis and Infertility: Role of Axonemal Alteration in Apical Endometria

ABSTRACT

Uterine adenomyosis is an estrogen-dependent chronic inflammatory condition and may cause painful symptoms, abnormal uterine bleeding, and/or subfertility/infertility. It is characterized by the presence of endometrial glands and stroma within the myometrium causing enlargement of the uterus as a result of reactive hyperplastic and/or hypertrophic change of the surrounding myometrium. Similar to endometriosis, adenomyosis has a negative impact on female fertility. Abnormal uterotubal sperm transport, tissue inflammation, and the toxic effect of chemical mediators have been proposed as contributing factors. Inflammation-induced damage of the mucosal cilia in the fallopian tube has been reported. Besides other proposed mechanisms, our most recent study with transmission electron microscopy analysis indicated that microvilli damage and an axonemal alteration in the apical endometria occur in response to endometrial inflammation. This may be involved in the negative fertility outcome in women with adenomyosis. We present a critical analysis of the literature data concerning the mechanistic basis of infertility in women with adenomyosis and its impact on fertility outcome.

Regeneration and anti-inflammatory effects of stem cells and their extracellular vesicles in gynecological diseases

There are many gynecological diseases, among which breast cancer (BC), cervical cancer (CC), endometriosis (EMs), and polycystic ovary syndrome (PCOS) are common and difficult to cure. Stem cells (SCs) are a focus of regenerative medicine. They are commonly used to treat organ damage and difficult diseases because of their potential for self-renewal and multidirectional differentiation. SCs are also commonly used for difficult-to-treat gynecological diseases because of their strong directional differentiation ability with unlimited possibilities, their tendency to adhere to the diseased tissue site, and their use as carriers for drug delivery. SCs can produce exosomes in a paracrine manner. Exosomes can be produced in large quantities and have the advantage of easy storage. Their safety and efficacy are superior to those of SCs, which have considerable potential in gynecological treatment, such as inhibiting endometrial senescence, promoting vascular reconstruction, and improving anti-inflammatory and immune functions. In this paper, we review the mechanisms of the regenerative and anti-inflammatory capacity of SCs and exosomes in incurable gynecological diseases and the current progress in their application in genetic engineering to provide a foundation for further research.

Pregnancy Outcomes after Uterus-sparing Operative Treatment for Adenomyosis: A Systematic Review and Meta-analysis

OBJECTIVE

A meta-analysis was conducted to evaluate the overall pregnancy outcomes after uterus-sparing operative treatment in patients with adenomyosis (AD).

DATA SOURCES

We searched PubMed, Web of Science, Cochrane Library, and Embase for literature from January 2000 to January 2022.

METHODS OF STUDY SELECTION

We included all studies reporting reproductive outcomes of uterine-sparing surgery for patients with AD with fertility requirements. Surgical treatment was classified as complete excision or incomplete removal of AD and nonexcisional techniques for induction of necrosis in AD. The latter included physically removing the tissue where pathology is present or disrupting the blood flow to the affected area, involving high-intensity focused ultrasound, microwave ablation, radiofrequency ablation, and uterine artery embolization. Two independent researchers performed study selection according to the screening criteria.

TABULATION, INTEGRATION, AND RESULTS

A total of 13 studies with 1319 patients with AD were included in this study, comprising 795 women wishing fertility. Pooled estimates of pregnancy, miscarriage, and live-birth rates after excisional treatment for women attempting to conceive were 40% (95% confidence interval [CI], 29-52), 21% (95% CI, 16-27), and 70% (95% CI, 64-76), respectively, and corresponding rates after nonexcisional treatment were 51% (95% CI, 42-60), 22% (95% CI, 13-34), and 71% (95% CI, 57-83), respectively. The differences were not statistically significant.

CONCLUSION

Excisional treatment could be a treatment consideration for patients with symptomatic AD and infertility for several years or repeated failure of assisted reproductive technology. Nonexcisional techniques may be considered probably for AD-related infertility.

A novel and rare diverticulum-like adenomyosis: A case report

INTRODUCTION

Cystic adenomyosis is a rare variant of adenomyosis, with only 90 reported cases found in the literature so far. Diverticulum-like adenomyosis is even more uncommon, with only one documented case to date.

CASE PRESENTATION

We report the case of a 42-year-old asymptomatic woman who had an incidental finding of a parauterine cyst on an abdominal computed tomography scan. B-ultrasonography also revealed an endometriotic cyst. Further MRI revealed a cystic lesion measuring 7.6 × 6.1 × 7.7 cm that communicated with the uterine cavity through a tiny channel. The fluid in the cyst showed high signal intensity on T1-weighted image (T1WI), and the cyst wall showed a marked low signal intensity on T2-weighted image (T2WI). No other masses were found on either side. After obtaining informed consent, we performed a laparoscopic exploration on the patient, where it became apparent that the 7.6 × 6.1 × 7.7 cm cystic mass was located on the left uterine isthmus-the excised lesion contained chocolate-like fluid within a thickened wall. Pathological examination revealed typical endometrial glands and interstitial tissues in the cystic wall.

DISCUSSION

Cystic adenomyosis is a rare benign lesion in women of reproductive age that is known to cause hypermenorrhea, dysmenorrhea, and abnormal uterine bleeding. Our case represents the second documented case of diverticulum-like adenomyosis. However, the patient in our case did not exhibit abnormal uterine bleeding or dysmenorrhea. One possible explanation for this finding is that the sinus tract was too small to cause blood influx into the uterine cavity.

CONCLUSION

Our case report provides valuable insights for clinicians to better understand this uncommon disease and reduce the incidence of misdiagnosis.

Different subtypes of ultrasound-diagnosed adenomyosis and in vitro fertilization outcomes: A systematic review and meta-analysis

INTRODUCTION

Adenomyosis prevalence among women with infertility is increasing; their management during in vitro fertilization is usually based on ultrasound diagnosis alone. Herein, we summarize the latest evidence on the impact of ultrasound-diagnosed adenomyosis on in vitro fertilization outcomes.

MATERIAL AND METHODS

The study was registered with The International Prospective Register of Systematic Reviews (CRD42022355584). We searched PubMed, Embase, and Cochrane Library databases from inception to January 31, 2023, for cohort studies on the impact of adenomyosis on in vitro fertilization outcomes. Fertility outcomes were compared according to the presence of adenomyosis as diagnosed by ultrasound, concurrent endometriosis and adenomyosis, and MRI-based or MRI- and ultrasound-based adenomyosis diagnosis. Live birth rate was the primary outcome while clinical pregnancy and miscarriage rates were secondary outcomes.

RESULTS

Women diagnosed with adenomyosis by ultrasound had lower live birth (odds ratio [OR] = 0.66; 95% confidence interval [CI]: 0.53-0.82, grade: very low), lower clinical pregnancy (OR = 0.64; 95% CI: 0.53-0.77, grade: very low), and higher miscarriage (OR = 1.81; 95% CI: 1.35-2.44, grade: very low) rates than those without adenomyosis. Notably, symptomatic and diffuse, but not asymptomatic adenomyosis as diagnosed by ultrasound, adversely affected in vitro fertilization outcomes, with lower live birth (OR = 0.57; 95% CI: 0.34-0.96, grade: very low), clinical pregnancy (OR = 0.69; 95% CI: 0.57-0.85, grade: low), and miscarriage (OR = 2.48, 95% CI: 1.28-4.82, grade: low) rates; and lower live birth (OR = 0.37; 95% CI: 0.23-0.59, grade: low) and clinical pregnancy (OR = 0.50; 95% CI: 0.34-0.75, grade: low), but not miscarriage rate (OR = 2.18; 95% CI: 0.72-6.62, grade: very low), respectively. Concurrent adenomyosis in endometriosis is associated with a significantly lower live birth rate (OR = 0.44; 95% CI: 0.26-0.75, grade: low) than endometriosis alone. Finally, the use of MRI-based or MRI- and ultrasound-based adenomyosis diagnosis showed no significant association with in vitro fertilization outcomes (grade: very low for all outcomes).

CONCLUSIONS

Considering ultrasound findings, symptoms, and different subtypes of adenomyosis may aid in offering personalized counseling, improving treatment decisions, and achieving better outcomes of in vitro fertilization.

Individualized conservative therapeutic strategies for adenomyosis with the aim of preserving fertility

Adenomyosis is a diffuse or localized organic disease caused by benign invasion of endometrial glands and stroma into the myometrium. It is a common disease that seriously affects reproductive health of women in childbearing age. Due to the unknown etiology and pathophysiological mechanism, and the lack of unified diagnostic criteria and effective treatment methods, total or subtotal hysterectomy has become a radical treatment for adenomyosis, which will lead to the complete loss of fertility. With the continuous exploration of the treatment to adenomyotic patients who have infertility or fertility intentions, new drugs, surgical methods and treating concepts appears. Adopt individualized conservative therapeutic strategies for patients with different conditions, preserve the uterus as much as possible and protect the patient’s fertility, which will play an important role on the follow-up assisted reproductive treatment and long-term management of adenomyosis.

Sonographic features of adenomyosis correlated with clinical symptoms and intraoperative findings: a case-control study

PURPOSE

Adenomyosis is a common disease of females during their reproductive age. As of today, histologic examination of the uterus after hysterectomy constitutes the gold standard for diagnosis. The aim of this study was to determine the validity of sonographic, hysteroscopic, and laparoscopic criteria for the diagnosis of the disease.

METHODS

This study included data collected from 50 women in the reproductive age of 18-45 years, who underwent a laparoscopic hysterectomy in the gynecology department of the Saarland University Hospital in Homburg between 2017 and 2018. The patients with adenomyosis were compared with a healthy control group.

RESULTS

We collected data of anamnesis, sonographic criteria, hysteroscopic criteria and laparoscopic criteria and compared it with the postoperative histological results. A total 25 patients were diagnosed with adenomyosis postoperatively. For each of these; at least three sonographic diagnostical criteria for adenomyosis were found compared with a maximum of two for the control group.

CONCLUSION

This study demonstrated an association between pre- and intraoperative signs of adenomyosis. In this way, it shows a high diagnostic accuracy of the sonographic examination as a pre-operative diagnostic method of the adenomyosis.

Bioinformatic analysis and machine learning to identify the diagnostic biomarkers and immune infiltration in adenomyosis

Background: Adenomyosis is a hormone-dependent benign gynecological disease characterized by the invasion of the endometrium into the myometrium. Women with adenomyosis can suffer from abnormal uterine bleeding, severe pelvic pain, and subfertility or infertility, which can interfere with their quality of life. However, effective diagnostic biomarkers for adenomyosis are currently lacking. The aim of this study is to explore the mechanism of adenomyosis by identifying biomarkers and potential therapeutic targets for adenomyosis and analyzing their correlation with immune infiltration in adenomyosis. Methods: Two datasets, GSE78851 and GSE68870, were downloaded and merged for differential expression analysis and functional enrichment analysis using R software. Weighted gene co-expression network analysis (WGCNA), the least absolute shrinkage and selection operator (LASSO), and support vector machine-recursive feature elimination (SVE-RFE) were combined to explore candidate genes. Quantitative reverse transcriptase PCR (qRT-PCR) was conducted to verify the biomarkers and receiver operating characteristic curve analysis was used to assess the diagnostic value of each biomarker. Single-sample Gene Set Enrichment Analysis (ssGSEA) and CIBERSORT were used to explore immune cell infiltration in adenomyosis and the correlation between diagnostic biomarkers and immune cells. Results: A total of 318 genes were differentially expressed. Through the analysis of differentially expressed genes and WGCNA, we obtained 189 adenomyosis-related genes. After utilizing the LASSO and SVM-RFE algorithms, four hub genes, namely, six-transmembrane epithelial antigen of the prostate-1 (STEAP1), translocase of outer mitochondrial membrane 20 (TOMM20), glycosyltransferase eight domain-containing 2 (GLT8D2), and NME/NM23 family member 5 (NME5) expressed in nucleoside-diphosphate kinase, were identified and verified by qRT-PCR. Immune infiltration analysis indicated that T helper 17 cells, CD56dim natural killer cells, monocytes, and memory B-cell may be associated with the occurrence of adenomyosis. There were significant correlations between the diagnostic biomarkers and immune cells. Conclusion: STEAP1, TOMM20, GLT8D2, and NME5 were identified as potential biomarkers and therapeutic targets for adenomyosis. Immune infiltration may contribute to the onset and progression of adenomyosis.