Endometriosis · Pathophysiology
Abstract
Endometriosis is a sex hormone-dependent and successively progressing gynecological disease, characterized by the presence of endometrial tissue outside the uterus. The etiology of endometriosis is known to be multifactorial, and its growth depends on immunological, hormonal, genetic and environmental factors. Angiogenesis plays a key role in implantation and growth of endometriotic lesions, as well as in adhesion formation. Physiologically angiogenesis is responsible for neoangiogenesis and recruitment of new capillaries from the already existing capillaries. It is well-documented that altered angiogenesis provokes improper follicular maturation, infertility recurrent miscarriages, ovarian hyperstimulation syndrome, and carcinogenesis. Factors stimulating angionesis include angiogenin, vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF).
The aim of the study was to analyze angiogenic factor concentration (angiogenin, VEGF, FGF) in blood serum and peritoneal fluid in patients with diagnosed endometriosis and idiopathic infertility.
A total of 39 patients were recruited for the study including 19 patients (study group) diagnosed with endometriosis during the laparoscopic procedure and 20 patients (control group) with idiopathic infertility and no morphologic changes within the pelvis revealed during the laparoscopic procedure. All patients underwent laparoscopy during the follicular phase of the menstrual cycle. Vein blood sample was obtained before the procedure and during laparoscopy the entire peritoneal fluid was aspirated for further measurement of VEGF, FGF and angiogenin concentrations.
Angiogenin concentration in peritoneal fluid was statistically higher in patient with idiopathic infertility in comparison to endometriosis (p<0.05). Higher angiogenin concentration was detected also in blood serum of patients with idiopathic infertility as compared to patients with endometriosis, but no statistical significance was found. VEGF and FGF concentration in blood serum and peritoneal fluid was similar in both groups (p>0.05). There were no significant differences between serum and peritoneal fluid in case of VEGF FGF and angiogenin in any of the groups.
Angiogenic factors concentration (VEGF FGF agiogenin) in the peritoneal fluid and blood serum during the follicular phase of the menstrual cycle is not a diagnostic criterion for endometriosis.
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By this author
Detection of peritoneal, ovarian, and bowel endometriosis using FTIR spectroscopy and machine learning
Olcha P et al., 2026 · Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy
This study evaluated the diagnostic potential of Fourier-transform infrared (FTIR) spectroscopy combined with machine learning for the detection of ovarian, bowel, and peritoneal endometriosis. The Boruta algorithm was applied to identify the most informative spectral intervals for each endometriosis type, revealing characteristic wave number ranges associated with molecular changes in endometriotic tissue. For ovarian endometriosis, key intervals included 741-748 cm-1, 984-993 cm-1, and 1125-1132 cm-1 bowel endometriosis, 1055-1063 cm-1, 1077-1079 cm-1, 1561-1572 cm-1, and 1717-1720 cm-1, and for peritoneal endometriosis, 917-919 cm-1, 1542-1547 cm-1, and 1573-1576 cm-1. Three machine learning algorithms, Deep Learning (DL), Support Vector Machine (SVM), and XGBoost, were tested using both the full spectral range and the Boruta-selected feature subsets. Across all endometriosis types, XGBoost consistently outperformed DL and SVM. Using the full spectrum, XGBoost achieved accuracies of 0.81, 0.77, and 0.78 for ovarian, bowel, and peritoneal endometriosis, respectively. Feature selection with Boruta significantly improved performance, increasing accuracies to 0.93, 0.88, and 0.90, respectively, and enhancing sensitivity, specificity, precision, F1 score, MCC, and ROC AUC across all datasets. DL models often exhibited high sensitivity but poor specificity, while SVM performance improved moderately with feature selection. Overall, these results demonstrate that targeted spectral feature selection enhances the diagnostic accuracy of machine learning models for endometriosis. XGBoost, in combination with Boruta-selected spectral intervals, provides the most reliable and balanced predictions, highlighting its potential for non-invasive detection and differentiation of ovarian, bowel, and peritoneal endometriotic lesions.
Effects of topical dehydroepiandrosterone therapy in women after pelvic organ prolapse surgery
Nowakowski Ł et al., 2023 · Menopause (New York, N.Y.)
Pelvic organ prolapse (POP) occurs predominantly in postmenopausal women. Restoration of the proper estrogenization of vaginal mucosa is important in preoperative and postoperative treatment, increasing the effectiveness of this approach. The objective of this study was the development of intravaginal vaginal suppositories containing DHEA and comparison of the clinical effects of vaginal topical therapy with DHEA, estradiol, or antibiotic after POP surgery. Nine types of vaginal suppositories containing 6.5 mg DHEA in different bases were prepared to find optimal formulation for the vaginal conditions. Ninety women referred for POP surgery were randomly assigned to one of three groups receiving topical treatment in the postoperative period (estradiol, DHEA, or antibiotic). On admission to hospital and during follow-up vaginal pH, vaginal maturation index and vaginal symptoms were assessed. Vaginal suppositories with the base made from polyethylene glycol 1,000 without surfactants characterized the highest percentage of the released DHEA. In women treated with topical estradiol or DHEA a significant decrease in the number of parabasal cells, increase in superficial and intermediate cells in the vaginal smears, decrease in vaginal pH, and reduction of vaginal symptoms were observed. The use of topical therapy with DHEA or the use of topical therapy with estradiol in the postoperative period were both shown to improve maturation index, vaginal pH, and vaginal symptoms. The benefits of topical therapy with DHEA after pelvic organ prolapse repair brings similar results as estradiol, without potential systemic exposure to increased concentrations of sex steroids above levels observed in postmenopausal women.
International Natural Procreative Technology Evaluation and Surveillance of Treatment for Subfertility (iNEST): enrollment and methods
Stanford JB et al., 2022 · Hum Reprod Open · Free full text on PubMed Central
What is the feasibility of a prospective protocol to follow subfertile couples being treated with natural procreative technology for up to 3 years at multiple clinical sites? Overall, clinical sites had missing data for about one-third of participants, the proportion of participants responding to follow-up questionnaires during time periods when participant compensation was available (about two-thirds) was double that of time periods when participant compensation was not available (about one-third) and follow-up information was most complete for pregnancies and births (obtained from both clinics and participants). Several retrospective single-clinic studies from Canada, Ireland and the USA, with subfertile couples receiving restorative reproductive medicine, mostly natural procreative technology, have reported adjusted cumulative live birth rates ranging from 29% to 66%, for treatment for up to 2 years, with a mean women's age of about 35 years. The international Natural Procreative Technology Evaluation and Surveillance of Treatment for Subfertility (iNEST) was designed as a multicenter, prospective cohort study, to enroll subfertile couples seeking treatment for live birth, assess baseline characteristics and follow them up for up to 3 years to report diagnoses, treatments and outcomes of pregnancy and live birth. In addition to obtaining data from medical record abstraction, we sent follow-up questionnaires to participants (both women and men) to obtain information about treatments and pregnancy outcomes, including whether they obtained treatment elsewhere. The study was conducted from 2006 to 2016, with a total of 10 clinics participating for at least some of the study period across four countries (Canada, Poland, UK and USA). The 834 participants were subfertile couples with the woman's age 18 years or more, not pregnant and seeking a live birth, with at least one clinic visit. Couples with known absolute infertility were excluded (i.e. bilateral tubal blockage, azoospermia). Most women were trained to use a standardized protocol for daily vulvar observation, description and recording of cervical mucus and vaginal bleeding (the Creighton Model FertilityCare System). Couples received medical and sometimes surgical evaluation and treatments aimed to restore and optimize female and male reproductive function, to facilitate in vivo conception. MAIN The mean age of women starting treatment was 34.0 years; among those with additional demographic data, 382/478 (80%) had 16 or more years of education, and 199/659 (30%) had a prior live birth. Across 10 clinical sites in four countries (mostly private clinical practices) with family physicians or obstetrician-gynecologists, data about clinic visits were submitted for 60% of participants, and diagnostic data for 77%. For data obtained directly from the couple, 59% of couples had at least one follow-up questionnaire, and the proportion of women and men responding to fill out the follow-up questionnaires was 69% and 67%, respectively, when participant financial compensation was available, compared to 38% and 33% when compensation was not available. Among all couples, 57% had at least one pregnancy and 44% at least one live birth during the follow-up time period, based on data obtained from clinic and/or participant questionnaires. All sites reported on female pelvic surgical procedures, and among all participants, 22% of females underwent a pelvic diagnostic and/or therapeutic procedure, predominantly laparoscopy and hysterosalpingography. Among the 643 (77%) of participants with diagnostic information, ovulation-related disorders were diagnosed in 87%, endometriosis in 31%, nutritional disorders in 47% and abnormalities of semen analysis in 24%. The mean number of diagnoses per couple was 4.7. LIMITATIONS The level of missing data was higher than anticipated, which limits both generalizability and the ability to study different components of treatment and prognosis. Loss to follow-up may also be differential and introduce bias for outcomes. Most of the participating clinicians were not surgeons, which limits the opportunity to study the impact of surgical interventions. Participants were geographically dispersed but relatively homogeneous with regard to socioeconomic status, which may limit the generalizability of current and future findings. Multicenter studies are key to understanding the outcomes of subfertility treatments beyond IVF or IUI in broader populations, and the association of different prognostic factors with outcomes. We anticipate that the iNEST study will provide insight for clinical and treatment factors associated with outcomes of pregnancy and live birth, with appropriate attention to potential biases (including adjustment for potential confounders, multiple imputation for missing data, sensitivity analysis and inverse probability weighting for potential differential loss to follow-up, and assessments for clinical site heterogeneity). Future studies will need to either have: adequate funding to compensate clinics and participants for robust data collection, including targeted randomized trials; or a scaled-down, registry-based approach with targeted data points, similar to the multiple national and regional ART registries. Funding for the study came from the International Institute for Restorative Reproductive Medicine, the University of Utah, Department of Family and Preventive Medicine, Health Studies Fund, the Primary Children's Medical Foundation, the Mary Cross Tippmann Foundation, the Atlas Foundation, the St. Augustine Foundation and the Women's Reproductive Health Foundation. The authors declare no competing interests. The iNEST study is registered at clinicaltrials.gov, NCT01363596.
Fertility-Sparing Methods in Adolescents Affected by Endometrial Cancer: A Comprehensive Review
Gałczyński K et al., 2021 · Journal of clinical medicine · Free full text on PubMed Central
Although in developed countries endometrial cancer (EC) is the most common gynecological malignancy, its occurrence in adolescents is exceedingly rare. The increasing rate of obesity in children and adolescents is held responsible for the increasing prevalence of EC in younger cohorts of patients. The diagnosis of this malignancy can have devastating consequences for future fertility because standard treatment protocols for EC include hysterectomy. Here, we present the first detailed review of the world literature on EC in subjects aged 21 years or younger (n = 19). The mean age at diagnosis was 16.7 ± 0.6 years. One patient (5.3%) had a Type II (high-risk) disease. No communication retrieved from the search reported on patient death; however, two (10.5%) patients were lost to follow-up. There was also a high proportion (five subjects, or 26.3%) of cases with genetic background (Cowden syndrome and Turner syndrome), therefore genetic screening or a direct genetic study should be considered in very young patients with EC. The current fertility-sparing options, limited to Type I (low-risk) disease, are presented and discussed. Such information, obtained from studies on older women, translates well to adolescent girls and very young women. Careful anatomopathological monitoring at follow-up is essential for the safety of a conservative approach. Improved survival in very young EC patients makes the preservation of fertility a central survivorship issue, therefore both patients and caregivers should undergo counseling regarding available options. Moreover, our study suggests that genetic syndromes other than Lynch syndrome may be associated with EC more frequently than previously thought.
Related research
Peritoneal fluid: its relevance to the development of endometriosis
Ramey JW et al., 1993 · Fertil Steril
To review and evaluate published studies that have examined the role of peritoneal fluid (PF) in the development of endometriosis. Important studies related to this topic have been identified through a computerized bibliographical search (MEDLINE), as well as by manually scanning the published literature of major reproductive journals over the last several years. Studies that examined the effect of PF or its components on the pathophysiology of endometriosis are discussed. These include reported effects on the histogenesis, maintenance and proliferation of endometriosis, as well as related actions on infertility. The majority of investigations into the role PF plays in the pathogenesis of endometriosis have evaluated how it may adversely affect fertility. Suggestive but inconclusive data in the literature indicate that degenerating endometrial tissue may release a biochemical factor(s) into the peritoneal environment that is capable of inducing ectopic endometrium formation. Peritoneal fluid itself contains growth factor that may play a role in the implantation and maintenance of the ectopic endometrium. The PF of women with endometriosis has been shown to contain angiogenic as well as other growth factors. These compounds may contribute to the proliferation of the ectopic endometrium.
Endometrial tissue in peritoneal fluid
Bartosik D et al., 1986 · Fertil Steril
Peritoneal fluid (PF) was studied for the presence of endometrial tissue in a consecutive series of 67 women (with documented tubal patency) undergoing diagnostic laparoscopy, tubal lavage, and hysteroscopy. PF was completely aspirated from the cul-de-sac both before and after uterine irrigation. The PF was then analyzed for the presence of endometrial tissue. In native PF no significant difference in the incidence of endometrial tissue between patients with (19%) and without (11%) endometriosis (P = 0.6) was observed. Refluxed PF, obtained after uterine irrigation, showed a significantly higher incidence of endometrial tissue in women with endometriosis (76%) as compared to controls (42%) (P = 0.03). We propose two models to explain the development of endometriosis. These are not mutually exclusive, may be independent of each other, and may represent two distinct pathophysiologic disease processes.
Comparison of cytokine levels and embryo toxicity in peritoneal fluid in infertile women with untreated or treated endometriosis
Taketani Y et al., 1992 · Am J Obstet Gynecol
Our aim was to examine the relationship between the levels of cytokines in peritoneal fluid and its embryo toxicity. The levels of interleukin-1 and tumor necrosis factor were measured in peritoneal fluid from infertile women who did not have endometriosis (n = 21), who had untreated endometriosis (n = 19), and who had undergone medical treatment for endometriosis (n = 10). Embryo toxicity was investigated in mouse two-cell embryos cocultured with the oviducts in culture media that contained various concentrations of peritoneal fluid. The levels of cytokines were significantly higher in the peritoneal fluid from women who had untreated endometriosis than in women who did not have endometriosis, but they were extremely low in women who had undergone medical treatment with either danazol or buserelin. The peritoneal fluid from women who had untreated endometriosis adversely affected the cleavage of mouse two-cell embryos. After medical treatment the embryo toxicity of the peritoneal fluid was almost undetectable. These results offer some theoretic bases in support of medical treatment to improve reproductive performance in infertile women who have endometriosis.
Status of current research on endometriosis
Giudice LC et al., 1998 · J Reprod Med
Endometriosis, a benign gynecologic disorder, occurs in about 10% of women of reproductive age and in up to 50% of women with infertility. Endometriosis is defined as the presence of endometrial glandular and stromal cells outside their normal location in the uterus. Commonly affected areas in the abdominopelvic cavity include the ovaries, the cul-desac and other kinds of pelvic peritoneum, bowel and diaphragm. Rarely is it found in extraabdominal sites, including the pleura and pericardium. While it is not a malignant disorder, endometriosis exhibits cellular proliferation, cellular invasion and neoangiogenesis. The steroid hormone dependence of endometriosis is underscored by its appearance during the reproductive years. Furthermore, the progress of this enigmatic disease can be tempered by administration of antiestrogens, inhibitors of endogenous estradiol production, and hormonal and surgical castration. It is a disorder that markedly affects well-being and physical and emotional health in women. Research on the pathogenesis of endometriosis currently interfaces with four areas of basic research, including the fields of genetics, environmental science, cancer biology and immunology. Here we focus on current research in the latter two disciplines and their relevance to endometriosis research.