Characterizing the endometrial fluid cytokine profile in women with endometriosis

Exercise and endometriosis-is there a promising future? A narrative review

BACKGROUND

Endometriosis is the leading cause of chronic pelvic pain in women of reproductive age with debilitating effects on quality of life, yet no cure exists. Exercise yields the potential in providing women with a non-invasive, non-pharmacological method of symptom control.

AIM(S)

Present up-to-date knowledge regarding how exercise may contribute to the management of endometriosis-related symptoms.

OBJECTIVE(S)

Discuss: 1. The pathophysiology surrounding exercise and endometriosis. 2. The role of exercise in endometriosis symptom control.

RATIONALE

Scientific literature has alluded to exercise being a favourable factor in the management of endometriosis-related symptoms. Moreover, current clinical guidelines for endometriosis fail to reflect the aforementioned benefits of exercise.

SEARCH STRATEGY

A search strategy using the terms 'endometriosis', 'endometriomas', 'exercise', and 'physical activity' was devised. Pubmed, Medline, Cochrane reviews, and Embase were reviewed.

INCLUSION CRITERIA

Interventional studies, within-subjects studies, randomised-control trials, systematic reviews, meta-analysis, cohort studies, publication since 2000.

EXCLUSION CRITERIA

Non-English publications, non-human studies.

RESULTS

Numerous studies have suggested positive effects for endometriosis patients who performed exercise exclusively or in conjunction with other therapies. Improvements in pain levels, quality of life, anxiety, and depression were noted.

DISCUSSION

Current research outlines promise regarding the potential benefit of exercise prescribing in patients with endometriosis as well as a synergy between exercise and hormonal therapies for the management of endometriosis-related symptoms. However, the current paucity of high-quality robust studies investigating these aspects of endometriosis management is an apparent obstacle to progression in this area.

CONCLUSION

For clinicians to incorporate exercise in managing endometriosis, clear recommendations regarding advice and benefits are needed.

Omics-based novel strategies in the diagnosis of endometriosis

Endometriosis, an enigmatic and chronic disorder, is considered a debilitating condition despite being benign. Globally, this gynecologic disorder affects up to 10% of females of reproductive age, impacting almost 190 million individuals. A variety of genetic and environmental factors are involved in endometriosis development, hence the pathophysiology and etiology of endometriosis remain unclear. The uncertainty of the etiology of the disease and its complexity along with nonspecific symptoms have led to misdiagnosis or lack of diagnosis of affected people. Biopsy and laparoscopy are referred to as the gold standard for endometriosis diagnosis. However, the invasiveness of the procedure, the unnecessary operation in disease-free women, and the dependence of the reliability of diagnosis on experience in this area are considered the most significant limitations. Therefore, continuous studies have attempted to offer a noninvasive and reliable approach. The recent advances in modern technologies have led to the generation of large-scale biological data sets, known as -omics data, resulting in the proceeding of the -omics century in biomedical sciences. Thereby, the present study critically reviews novel and noninvasive biomarkers that are based on -omics approaches from 2020 onward. The findings reveal that biomarkers identified based on genomics, epigenomics, transcriptomics, proteomics, and metabolomics are potentially able to diagnose endometriosis, predict prognosis, and stage patients, and potentially, in the near future, a multi-panel of these biomarkers will generate clinical benefits.

The Impact of Endometriosis on Pregnancy

Despite the increased frequency of endometriosis, it remains one of the most enigmatic disorders regarding its effects on pregnancy. Endometriosis adversely affects both natural and assisted conception. Impaired folliculogenesis, which causes follicular dysfunction and low egg quality, as well as luteal phase problems, reduced fertilization, and abnormal embryogenesis, are some of the mechanisms advocated to explain reproductive dysfunction. There is a rising need for a comprehensive study of the potential negative consequences of this condition on pregnancy outcomes, including the postpartum period, as more women with a medical history of endometriosis become pregnant. Obstetrical complications (small for gestational age [SGA], cesarean section [CS], miscarriage, hemorrhage, low placental adhesion, and preterm delivery) are statistically elevated in women with endometriosis. Furthermore, ruptured ovarian endometrioma, appendicitis, intestinal perforation, and hemoperitoneum have been described in pregnancy. Obstetricians are largely unfamiliar with these complications, as they have not been thoroughly investigated. The development and pathogenesis of endometriosis is an important field of study and has not yet been fully elucidated. Finding these mechanisms is crucial for the development of new and more effective strategies to treat this condition. Endometriosis can have an impact on obstetric and neonatal outcomes of pregnancy, in addition to its potential effects on conception. To date, no additional monitoring is recommended for pregnancies with a history of endometriosis. However, more studies are urgently needed to assess the need for the tailored pregnancy monitoring of women with endometriosis.

The Pathological Role of miRNAs in Endometriosis

Association studies investigating miRNA in relation to diseases have consistently shown significant alterations in miRNA expression, particularly within inflammatory pathways, where they regulate inflammatory cytokines, transcription factors (such as NF-κB, STAT3, HIF1α), and inflammatory proteins (including COX-2 and iNOS). Given that endometriosis (EMS) is characterized as an inflammatory disease, albeit one influenced by estrogen levels, it is natural to speculate about the connection between EMS and miRNA. Recent research has indeed confirmed alterations in the expression levels of numerous microRNAs (miRNAs) in both endometriotic lesions and the eutopic endometrium of women with EMS, when compared to healthy controls. The undeniable association of miRNAs with EMS hints at the emergence of a new era in the study of miRNA in the context of EMS. This article reviews the advancements made in understanding the pathological role of miRNA in EMS and its association with EMS-associated infertility. These findings contribute to the ongoing pursuit of developing miRNA-based therapeutics and diagnostic markers for EMS.

Endometrial fluid biomarkers and their potential as predictors of successful embryo implantation

Background

Embryo implantation is a complex biological process which requires synchronized dialogue between the receptive endometrium and the blastocyst. The endometrium, however, is only receptive to embryo implantation for a very short period. Recurrent implantation failure (RIF) is a major challenge in assisted reproductive techniques mainly due to impaired receptivity, but there is still a need for a reliable and valid clinical test to assess endometrial receptiveness, especially at embryo transfer time. The aim of this review is to investigate what is currently known about the contribution of endometrial fluid (EF) to endometrial receptivity by identifying its potential biomarkers.

Methods

This study involved an extensive search of the electronic databases PubMed and Cochrane, covering the period from 2011 to 2022. A combination of Medical Subject Headings with the terms 'endometrial fluid' and 'embryo implantation' was used.

Results

Several different proteins presented in the endometrial cavity fluid have been described but the most consistent as potential biomarkers were Proprotein Convertase 6 (PC6), Vascular Endothelial Growth Factor (VEGF), PIGF (Placental growth factor), β3 integrin, Colony Stimulating Factor-3 (CSF-3), Leukaemia inhibitory factor (LIF), glycodelin and extracellular vesicles (EVs).

Conclusions

Strong indicators support the use of uterine fluid collection as a non-invasive tool for receptivity assessment. Therefore, it could improve outcomes of assisted reproductive techniques.

Organoid co-culture model of the human endometrium in a fully synthetic extracellular matrix enables the study of epithelial-stromal crosstalk

BACKGROUND

The human endometrium undergoes recurring cycles of growth, differentiation, and breakdown in response to sex hormones. Dysregulation of epithelial-stromal communication during hormone-mediated signaling may be linked to myriad gynecological disorders for which treatments remain inadequate. Here, we describe a completely defined, synthetic extracellular matrix that enables co-culture of human endometrial epithelial and stromal cells in a manner that captures healthy and disease states across a simulated menstrual cycle.

METHODS

We parsed cycle-dependent endometrial integrin expression and matrix composition to define candidate cell-matrix interaction cues for inclusion in a polyethylene glycol (PEG)-based hydrogel crosslinked with matrix metalloproteinase-labile peptides. We semi-empirically screened a parameter space of biophysical and molecular features representative of the endometrium to define compositions suitable for hormone-driven expansion and differentiation of epithelial organoids, stromal cells, and co-cultures of the two cell types.

FINDINGS

Each cell type exhibited characteristic morphological and molecular responses to hormone changes when co-encapsulated in hydrogels tuned to a stiffness regime similar to the native tissue and functionalized with a collagen-derived adhesion peptide (GFOGER) and a fibronectin-derived peptide (PHSRN-K-RGD). Analysis of cell-cell crosstalk during interleukin 1B (IL1B)-induced inflammation revealed dysregulation of epithelial proliferation mediated by stromal cells.

CONCLUSIONS

Altogether, we demonstrate the development of a fully synthetic matrix to sustain the dynamic changes of the endometrial microenvironment and support its applications to understand menstrual health and endometriotic diseases.

FUNDING

This work was supported by The John and Karine Begg Foundation, the Manton Foundation, and NIH U01 (EB029132).

Identification and validation of risk score model based on gene set activity as a diagnostic biomarker for endometriosis

Objective

The enigmatic nature of Endometriosis (EMS) pathogenesis necessitates investigating alterations in signaling pathway activity to enhance our comprehension of the disease's characteristics.

Methods

Three published gene expression profiles (GSE11691, GSE25628, and GSE7305 datasets) were downloaded, and the "combat" algorithm was employed for batch correction, gene expression difference analysis, and pathway enrichment difference analysis. The protein-protein interaction (PPI) network was constructed to identify core genes, and the relative enrichment degree of gene sets was evaluated. The Lasso regression model identified candidate gene sets with diagnostic value, and a risk scoring diagnostic model was constructed for further validation on the GSE86534 and GSE5108 datasets. CIBERSORT was used to assess the composition of immune cells in EMS, and the correlation between EMS diagnostic value gene sets and immune cells was evaluated.

Results

A total of 568 differentially expressed genes were identified between eutopic and ectopic endometrium, with 10 core genes in the PPI network associated with cell cycle regulation. Inflammation-related pathways, including cytokine-receptor signaling and chemokine signaling pathways, were significantly more active in ectopic endometrium compared to eutopic endometrium. Diagnostic gene sets for EMS, such as homologous recombination, base excision repair, DNA replication, P53 signaling pathway, adherens junction, and SNARE interactions in vesicular transport, were identified. The risk score's area under the curve (AUC) was 0.854, as indicated by the receiver operating characteristic (ROC) curve, and the risk score's diagnostic value was validated by the validation cohort. Immune cell infiltration analysis revealed correlations between the risk score and Macrophages M2, Plasma cells, resting NK cells, activated NK cells, and regulatory T cells.

Conclusion

The risk scoring diagnostic model, based on pathway activity, demonstrates high diagnostic value and offers novel insights and strategies for the clinical diagnosis and treatment of Endometriosis.

Chronic poor healing wounds of post cesarean scar diverticulum: Altered angiogenesis and immunobiology

Cesarean section (CS) scar diverticula (CSD) is an important cause impede further fecundity, with rather complicated pathophysiologic mechanisms and unclear etiopathogenesis. In this study, we detect the influences of CSD on the pregnancy outcomes in in-vitro fertilization (IVF) or intra-cytoplasmic sperm injection (ICSI) embryo transfer (ET) cycles, and further explore the mechanisms involved based on histopathology and immunology differences in endometrium between CSD and vaginal birth (VB) women. The CS group had significantly lower CLBR compared to NCS group. Histopathological analysis showed that the higher prevalent of CE is accompanied by excessive fibroblast proliferation at the lower segment of uterus and significantly exaggerated vascular proliferation in situ. Intrauterine inflammatory cytokines including IL-1α, IL-1β, IL-6, IL-8, TNF-α and SDF-1α were also increased in CSD group. The present data suggests impaired fecundity in CSD women undergoing IVF/ICSI treatment. Although the causal relationship is ambiguous, the potential mechanisms may involve persistent inflammatory response in the uterine cavity, active vascular proliferation accompanied with increased fibrosis which are responsible for poor chronic wound healing of CSD.

Lipoxin A4 depresses inflammation and promotes autophagy via AhR/mTOR/AKT pathway to suppress endometriosis

BACKGROUND

Endometriosis is a benign gynecological disease with the feature of estrogen dependence and inflammation. The function of autophagy and the correlation with inflammation were not yet revealed.

METHODS

Autophagosomes were detected by transmission electron microscopy. Gene Expression Omnibus (GEO) database was referred to analyze the expression of autophagy-related genes. Quantification of mRNA and protein expression was examined by qRT-PCR and Western Blot. Immunohistochemistry was performed to explore the expression of proteins in tissues. The mouse model of endometriosis was performed to analyze the autophagic activity and effect of LXA4.

RESULTS

The expression of autophagy-related genes in endometriotic lesions were unusually changed. The number of autophagosomes and LC3B-II expression was diminished, and p62 was increased in ectopic lesions from both patients and mice. Interleukin 1β (IL1β) attenuated the expression of LC3B and promoted the level p62. The autophagy activator MG-132 upregulated the expression of LC3B and reduced IL1β, IL6, and p62. LXA4 reversed the inhibitory effect of IL1β on the expression of LC3B and p62, and blocking the receptor of LXA4 AhR (aryl hydrocarbon receptor) resulted in the incapacitation of LXA4 to influence the effect of IL1β. LXA4 depressed the phosphorylation of AKT and mTOR to against IL1β, and blocking AhR negatively regulated the effect of LXA4 on AKT/mTOR pathway. LXA4 reduced the ectopic lesions and the expression of IL1β and p62, but enhanced LC3B-II in endometriotic mouse models.

CONCLUSION

In endometriosis, increased inflammation of ectopic lesions prominently depresses autophagy. LXA4 could regulate autophagy by suppressing inflammatory response through AhR/AKT/mTOR pathway.

Towards a Better Understanding of Endometriosis-Related Infertility: A Review on How Endometriosis Affects Endometrial Receptivity

Endometriosis is the most common cause of infertility. Endometrial receptivity has been suggested to contribute to infertility and poor reproductive outcomes in affected women. Even though experimental and clinical data suggest that the endometrium differs in women with endometriosis, the pathogenesis of impaired endometrial receptivity remains incomplete. Therefore, this review summarizes the potential mechanisms that affect endometrial function and contribute to implantation failure. Contemporary data regarding hormone imbalance, inflammation, and immunoregulatory dysfunction will be reviewed here. In addition, genetic, epigenetic, glycosylation, metabolism and microRNA in endometriosis-related infertility/subfertility will be summarized. We provide a brief discussion and perspectives on their future clinical implications in the diagnosis and therapy to improve endometrial function in affected women.

Ovulation Induced by Intrauterine Seminal Plasma Increases Total Protein, PGE2, IL-8, and IL-1β in Uterine Fluid of Llamas (Lama glama)

The establishment of a state of immunotolerance in the female reproductive tract is important for embryo development, implantation and placentation. Llamas are induced ovulators and more than 98% of pregnancies occur in the left uterine horn. The objective of this study was to determine the uterine immune response of llamas in different stages of the reproductive cycle. Adult llamas (n = 20) were examined daily by transrectal ultrasonography to determine follicular growth and then randomly assigned to four groups: Follicular phase (n = 5); Luteal phase induced by an intramuscular administration of 50 ug of GnRH analogue (n = 5); Luteal phase induced by intrauterine infusion of seminal plasma (n = 5); and Luteal phase induced by mating (n = 5). Uterine fluid was collected separately from both uterine horns by non-surgical flushing to determine the presence of cells, total proteins and concentration of IL-1β, IL-6, IL-8, IFN γ, TNF-α and PGE2. Inflammatory cells were not observed in the uterine fluid and total protein pattern and inflammatory mediators did not differ between the left and the right horn amongst groups. Llamas treated with an intrauterine infusion of seminal plasma showed the highest concentration of total proteins, inflammatory cytokines PGE2, IL-8 and IL-1β in the uterine fluid. In conclusion, seminal plasma is made up of significant numbers of signaling molecules that are able to modify the uterine immune response in llamas.

A syngeneic inoculation mouse model of endometriosis that develops multiple comorbid visceral and cutaneous pain like behaviours

ABSTRACT

Endometriosis is a chronic and debilitating condition, commonly characterised by chronic pelvic pain (CPP) and infertility. Chronic pelvic pain can be experienced across multiple pelvic organs, with comorbidities commonly effecting the bowel, bladder, and vagina. Despite research efforts into endometriosis pathophysiology, little is known about how endometriosis induces CPP, and as such, therapeutic interventions are lacking. The aim of this study was to characterise a syngeneic mouse model of endometriosis that mimics naturally occurring retrograde menstruation, thought to precede endometriosis development in patients, and determine whether these mice exhibit signs of CPP and altered behaviour. We characterised the development of endometriosis over 10 weeks following uterine tissue inoculation, measured in vivo and ex vivo hypersensitivity to mechanical stimuli across multiple visceral organs, and assessed alterations in animal spontaneous behaviour. We confirmed that inoculated uterine horn tissue formed into endometriosis lesions throughout the peritoneal cavity, with significant growth by 8 to 10 weeks post inoculation. Additionally, we found that mice with fully developed endometriosis displayed hypersensitivity evoked by (1) vaginal distension, (2) colorectal distension, (3) bladder distension, and (4) cutaneous thermal stimulation, compared to their sham counterparts. Moreover, endometriosis mice displayed alterations in spontaneous behaviour indicative of (5) altered bladder function and (6) anxiety. This model creates a foundation for mechanistical studies into the diffuse CPP associated with endometriosis and the development of targeted therapeutic interventions to improve the quality of life of women with endometriosis.

Molecular Insights into Endometrial Cancer in Mice

Pluripotent, very small embryonic-like stem cells (VSELs) and the 'progenitors' endometrial stem cells (EnSCs) along with associated molecular changes in endometrial cancer, that developed seven months after neonatal exposure to estradiol in one of the sixty mice, were studied in the present study. Endocrine disruption affected both endometrium and myometrium, there was accumulation of endometrial fluid and significant hyperplasia. Disrupted endometrial-myometrial junction resulted in mobilization of myometrial cells into endometrium and epithelial and stromal cells into myometrium suggestive of adenomyosis. Markers specific for VSELs/ EnSCs (OCT-4, NANOG, SSEA-1, SCA-1, c-KIT) showed increased expression in uterine sections and marked upregulation of corresponding transcripts (Oct-4A, Oct-4, Sox-2, Nanog, Sca-1, c-Kit) was noted in RNA extracted from both uterine tissue and stem cells enriched from endometrial fluid. Hormonal receptors (ER-α, ER-β, PR, FSHR) were upregulated in both tumor sections and in endometrial fluid. ER-β and FSHR (Fshr3) expression was prominent suggesting a major role in endometrial cancer. Cancer cells showed global hypomethylation (reduced expression of 5-methyl cytosine), reduced expression of tumor suppressor gene (PTEN) and increased expression of cancer stem cells marker (CD166) which suggested dysregulation and aberrant oncogenic events. Increased expression of PCNA, Ki67, SOX-9 suggested excessive proliferation and hyperplasia which are predominant signs of endometrial cancer. Results suggest that VSELs increase in numbers and possibly transform into cancer stem cells (co-express CD166 and OCT-4) in endometrial cancer. Expression of OCT-4, CD133, ALDHA1 and CD166 in side-population cells from human endometrial cancer samples suggests a possible role of VSELs in human endometrial cancer as well.