Epidermal growth factor in human endometrium: proliferative effects in culture and immunocytochemical localization in normal and endometriotic tissues

Distinct molecular targets of ProEGCG from EGCG and superior inhibition of angiogenesis signaling pathways for treatment of endometriosis

Endometriosis is a common chronic gynecological disease with endometrial cell implantation outside the uterus. Angiogenesis is a major pathophysiology in endometriosis. Our previous studies have demonstrated that the prodrug of epigallocatechin gallate (ProEGCG) exhibits superior anti-endometriotic and anti-angiogenic effects compared to epigallocatechin gallate (EGCG). However, their direct binding targets and underlying mechanisms for the differential effects remain unknown. In this study, we demonstrated that oral ProEGCG can be effective in preventing and treating endometriosis. Additionally, 1D and 2D Proteome Integral Solubility Alteration assay-based chemical proteomics identified metadherin (MTDH) and PX domain containing serine/threonine kinase-like (PXK) as novel binding targets of EGCG and ProEGCG, respectively. Computational simulation and BioLayer interferometry were used to confirm their binding affinity. Our results showed that MTDH-EGCG inhibited protein kinase B (Akt)-mediated angiogenesis, while PXK-ProEGCG inhibited epidermal growth factor (EGF)-mediated angiogenesis via the EGF/hypoxia-inducible factor (HIF-1a)/vascular endothelial growth factor (VEGF) pathway. In vitro and in vivo knockdown assays and microvascular network imaging further confirmed the involvement of these signaling pathways. Moreover, our study demonstrated that ProEGCG has superior therapeutic effects than EGCG by targeting distinct signal transduction pathways and may act as a novel antiangiogenic therapy for endometriosis.

Epidermal growth factor promotes stromal cells migration and invasion via up-regulation of hyaluronate synthase 2 and hyaluronan in endometriosis

OBJECTIVE

To investigate the role(s) of hyaluronan synthase 2 (HAS2) and hyaluronan in disease progression of endometriosis and epidermal growth factor (EGF)-induced motility changes of endometriotic cells.

DESIGN

A case-control experimental study and in vitro primary cell culture study.

SETTING

University hospital-affiliated research centers.

PATIENTS

A total of 21 women with stage I/II endometriosis, 33 women with stage III/IV endometriosis with endometrioma, and 32 women without endometriosis were included in our study.

INTERVENTIONS

Serum, eutopic endometrial tissues, and/or ectopic endometriotic tissues were collected. Primary eutopic endometrial stromal cells (EuESCs) and ectopic ovarian endometriotic stromal cells (OvESCs) were isolated and cultured from women with ovarian endometrioma, and then treated with or without EGF.

MAIN OUTCOME MEASURES

The concentrations of EGF and hyaluronan in serum were analyzed by enzyme-linked immunosorbent assay. The expressions and localizations of EGF receptor (EGFR), phosphorylated-(p)EGFR, HAS2, and hyaluronan receptor CD44 in tissues were examined by immunohistochemistry. The mRNA and protein levels of HAS2 in EuESCs and OvESCs were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot, respectively, and the concentrations of hyaluronan in conditioned medium were examined by enzyme-linked immunosorbent assay (ELISA). Cell motility was evaluated by transwell migration/invasion assays.

RESULTS

Serum EGF and hyaluronan concentrations were higher in women with stage III/IV endometriosis than in women with stage I/II or without endometriosis. EGFR, pEGFR, HAS2, and CD44 were immunolocalized in eutopic endometrium and ectopic endometriotic lesions, and the expressions of pEGFR and HAS2 were elevated in ectopic endometriotic lesions compared to eutopic endometrium. Treatment with EGF upregulated HAS2 and hyaluronan expression as well as cell migration and invasion in both EuESCs and OvESCs, and pharmaceutical blocking of EGFR abolished these effects. In addition, knockdown of HAS2 by small interfering RNA attenuated both basal and EGF-induced hyaluronan expression and cell motility changes. Notably, ERK1/2 and AKT signaling pathways were shown to be downstream of EGF in regulating HAS2 and hyaluronan expression as well as cell migration and invasion.

CONCLUSION

EGF increased the expression of endometriosis-associated hyaluronan and its synthase HAS2, both of which mediated EGF-induced stromal cell migration and invasion in women with endometriosis.

Nanoparticle-Based Platform for Activatable Fluorescence Imaging and Photothermal Ablation of Endometriosis

Endometriosis is a painful disorder where endometrium-like tissue forms lesions outside of the uterine cavity. Intraoperative identification and removal of these lesions are difficult. This study presents a nanoplatform that concurrently delineates and ablates endometriosis tissues using real-time near-infrared (NIR) fluorescence and photothermal therapy (PTT). The nanoplatform consists of a dye, silicon naphthalocyanine (SiNc), capable of both NIR fluorescence imaging and PTT, and a polymeric nanoparticle as a SiNc carrier to endometriosis tissue following systemic administration. To achieve high contrast during fluorescence imaging of endometriotic lesions, nanoparticles are constructed to be non-fluorescent prior to internalization by endometriosis cells. In vitro studies confirm that these nanoparticles activate the fluorescence signal following internalization in macaque endometrial stromal cells and ablate them by increasing cellular temperature to 53 ^° C upon interaction with NIR light. To demonstrate in vivo efficiency of the nanoparticles, biopsies of endometrium and endometriosis from rhesus macaques are transplanted into immunodeficient mice. Imaging with the intraoperative Fluobeam 800 system reveals that 24 h following intravenous injection, nanoparticles efficiently accumulate in, and demarcate, endometriotic grafts with fluorescence. Finally, the nanoparticles increase the temperature of endometriotic grafts up to 47 °C upon exposure to NIR light, completely eradicating them after a single treatment.

A High Protein Model Alters the Endometrial Transcriptome of Mares

High blood urea nitrogen (BUN) decreases fertility of several mammals; however, the mechanisms have not been investigated in mares. We developed an experimental model to elevate BUN, with urea and control treatments (7 mares/treatment), in a crossover design. Urea-treatment consisted of a loading dose of urea (0.03 g/kg of body weight (BW)) and urea injections over 6 hours (0.03 g/kg of BW/h). Control mares received the same volume of saline solution. Blood samples were collected to measure BUN. Uterine and vaginal pH were evaluated after the last intravenous infusion, then endometrial biopsies were collected for RNA-sequencing with a HiSeq 4000. Cuffdiff (2.2.1) was used to identify the differentially expressed genes (DEG) between urea and control groups (false discovery rate-adjusted p-value < 0.1). There was a significant increase in BUN and a decrease of uterine pH in the urea group compared to the control group. A total of 193 genes were DEG between the urea and control groups, with five genes identified as upstream regulators (ETV4, EGF, EHF, IRS2, and SGK1). The DEG were predicted to be related to cell pH, ion homeostasis, changes in epithelial tissue, and solute carriers. Changes in gene expression reveal alterations in endometrial function that could be associated with adverse effects on fertility of mares.

Hyaluronic Acid Hydrogel Integrated with Mesenchymal Stem Cell-Secretome to Treat Endometrial Injury in a Rat Model of Asherman's Syndrome

Stem cell therapies have made strides toward the efficacious treatment of injured endometrium and the prevention of intrauterine adhesions, or Asherman's syndrome (AS). Despite this progress, they are limited by their risk of tumor formation, low engraftment rates, as well as storage and transportation logistics. While attempts have been made to curb these issues, there remains a need for simple and effective solutions. A growing body of evidence supports the theory that delivering media, conditioned with mesenchymal stem cells, might be a promising alternative to live cell therapy. Mesenchymal stem cell-secretome (MSC-Sec) has a superior safety profile and can be stored without losing its regenerative properties. It is versatile enough to be added to a number of delivery vehicles that improve engraftment and control the release of the therapeutic. Thus, it holds great potential for the treatment of AS. Here, a new strategy for loading crosslinked hyaluronic acid gel (HA gel) with MSC-Sec is reported. The HA gel/MSC-Sec treatment paradigm creates a sustained release system that repairs endometrial injury in rats and promotes viable pregnancy.

Expression and Role of Peptides, Proteins and Growth Factors in the Pathogenesis of Endometriosis

Growing evidence is demonstrating that several peptides (corticotrophin-releasing factor, urocortins, ghrelin), proteins (leptin, adiponectin) and growth factors (vascular endothelial growth factor; epidermal growth factor family of growth factors and receptors, fibroblast growth factor, insulin like growth factor and insulin like growth factor-binding proteins, transforming growth factor-β and, activin A and related proteins) are expressed in endometriotic implants, and locally play a relevant role in affecting the biological mechanisms leading to endometriosis. They establish a complex network of interactions by which they are therefore able to stimulate angiogenesis, inflammatory cell recruitment and reaction, the growth of endometriotic tissue and its survival through the modulation of the narrow immune system. This review will evaluate the role played by several regulatory peptides, proteins and growth factors in affecting endometrial physiology and the putative mechanisms advocated to explain endometriosis (angiogenesis, cellular and humoral immunity, inflammatory response, endometrial cell proliferation, activation, motility, adhesion and invasion).

Growth factor induced proliferation, migration, and lumen formation of rat endometrial epithelial cells in vitro

Endometrial modulation is essential for the preservation of normal uterine physiology, and this modulation is driven by a number of growth factors. The present study investigated the mitogenic, motogenic, and morphogenic effects of epidermal growth factor (EGF) and hepatocyte growth factor (HGF) on rat endometrial epithelial (REE) cells. The REE cells were isolated and cultured and then characterized based on their morphology and their expression of epithelial cell markers. The MTT assay revealed that EGF and HGF induce proliferation of REE cells. Consistent with increased proliferation, we found that the cell cycle regulatory factor Cyclin D1 was also upregulated upon EGF and HGF addition. REE cell migration was prompted by EGF, as observed with the Oris Cell Migration Assay. The morphogenic impact of growth factors on REE cells was studied in a three-dimensional BD Matrigel cell culture system, wherein these growth factors also increased the frequency of lumen formation. In summary, we show that EGF and HGF have a stimulatory effect on REE cells, promoting proliferation, cell migration, and lumen formation. Our findings provide important insights that further the understanding of endometrial regeneration and its regulation.

MAP kinases and the inflammatory signaling cascade as targets for the treatment of endometriosis?

INTRODUCTION

The pathogenesis of endometriosis, a common benign disease, remains ill-defined, although it is clear that chronic inflammation plays a crucial role through mitogen-activated protein kinase (MAPK) signaling pathways. All current medical therapies for endometriosis are antigonadotropic, and therefore have a contraceptive effect. A concerted research effort is hence warranted with the aim of delivering novel therapeutics that reduces disease symptoms without blocking ovulation.

AREAS COVERED

The authors review the complex pathogenic mechanisms of chronic inflammation in endometriosis and their relationships with MAPK pathways. The authors conducted a literature search of descriptive and functional targeted validation of MAPK in the pathogenesis of endometriosis. The effects of MAPK inhibitors, which constitute potential agents for future treatments, are also described.

EXPERT OPINION

Preliminary studies have highlighted a crucial role for MAPK in driving endometriosis-related inflammation. MAPK inhibitors exhibit potent activity in terms of controlling growth of endometriosis lesions both in vitro and in animal models. As MAPK inhibitors are known to have a multitude of undesirable side effects, their use in humans has to be approached with great care. Indeed, use of these drugs would probably be limited to short exposures prior to surgery in cases involving the most severe disease phenotypes.

Lipoxin A₄ prevents the progression of de novo and established endometriosis in a mouse model by attenuating prostaglandin E₂ production and estrogen signaling

Endometriosis, a leading cause of pelvic pain and infertility, is characterized by ectopic growth of endometrial-like tissue and affects approximately 176 million women worldwide. The pathophysiology involves inflammatory and angiogenic mediators as well as estrogen-mediated signaling and novel, improved therapeutics targeting these pathways are necessary. The aim of this study was to investigate mechanisms leading to the establishment and progression of endometriosis as well as the effect of local treatment with Lipoxin A₄ (LXA₄), an anti-inflammatory and pro-resolving lipid mediator that we have recently characterized as an estrogen receptor agonist. LXA₄ treatment significantly reduced endometriotic lesion size and downregulated the pro-inflammatory cytokines IL-1β and IL-6, as well as the angiogenic factor VEGF. LXA₄ also inhibited COX-2 expression in both endometriotic lesions and peritoneal fluid cells, resulting in attenuated peritoneal fluid Prostaglandin E₂ (PGE₂) levels_. Besides its anti-inflammatory effects, LXA₄ differentially regulated the expression and activity of the matrix remodeling enzyme matrix metalloproteinase (MMP)-9 as well as modulating transforming growth factor (TGF)-β isoform expression within endometriotic lesions and in peritoneal fluid cells. We also report for first time that LXA₄ attenuated aromatase expression, estrogen signaling and estrogen-regulated genes implicated in cellular proliferation in a mouse model of disease. These effects were observed both when LXA₄ was administered prior to disease induction and during established disease. Collectively, our findings highlight potential targets for the treatment of endometriosis and suggest a pleotropic effect of LXA₄ on disease progression, by attenuating pro-inflammatory and angiogenic mediators, matrix remodeling enzymes, estrogen metabolism and signaling, as well as downstream proliferative pathways.

The role of prostaglandin E2 in endometriosis

Endometriosis is a leading cause of infertility in women of reproductive age. It involves the occurrence of endometrial tissue outside the uterine endometrium, mainly in the peritoneal cavity. Prostaglandin E(2) is up regulated in the peritoneal cavity in endometriosis and is produced by macrophages and ectopic endometrial cells. This prostaglandin is involved in the pathophysiology of the disease and elicits cell signals via four receptor types. Prostaglandin E(2) increases estrogen synthesis by up regulating steroidogenic acute regulatory protein (StAR) and aromatase. It inhibits apoptosis and up regulates fibroblast growth factor-9 (FGF-9) promoting cell proliferation. Prostaglandin E(2) affects leukocyte populations and promotes angiogenesis through its effect on estrogen and up regulation of vascular endothelial growth factor (VEGF). Dienogest is a synthetic progestin targeting expression of genes involved in prostaglandin synthesis.

Cytokines and Growth Factors in Implantation

Implantation failure is the most important rate limiting factor in the success of assisted reproductive techniques like In vitro fertilization–embryo transfer (IVF-ET). Cytokines are multifunctional signaling molecules having an implicit role in the human implantation process. This review focuses on the redundant roles of cytokines during the various stages of implantation. It also indicates that levels of cytokines in biological fluids like serum and follicular fluid obtained during oocyte retrieval might act as determinants of implantation potential of the blastocyst. Thus a holistic, metabolomic approach of analyzing biological fluids may provide a simpler approach to study the hitherto enigmatic process rather than the proteomic and genomic approach.

Prostaglandin E2: the master of endometriosis?

Endometriosis is the primary cause of infertility in women, with a prevalence rate ranging from 5% to 10%. Women with endometriosis suffer from symptoms such as chronic pelvic pain, dysmenorrhea and dyspareunia, which significantly reduce the quality of life. Endometriosis is a polygenic disease with a complex, multifactorial etiology. The mechanism responsible for the initiation and development of this disease remains largely unknown. Prostaglandin E2 (PGE2), a versatile eicosanoid that exerts numerous physiological and pathological functions, has been implicated to play critical roles in the development of endometriosis. A growing body of evidence demonstrates that PGE2 regulates many pathophysiological processes including cell proliferation, antiapoptosis, immune suppression and angiogenesis during the development of endometriosis. This review focuses on recent advances in cellular and molecular mechanisms triggered by PGE2 that contribute to the pathological processes of endometriosis.

The aetiology and pathogenesis of endometriosis

It is 130 years since the first description of endometriosis and yet this enigmatic disease still continues to confound gynaecologists. In the last five years there has been evidence which suggests that endometriosis is a much more common finding in the pelvis than previously recognized and this has created conflict over the precise definition of the disease. Currently it is difficult for clinicians to be certain what constitutes endometriosis and what is the clinical and pathological significance of the visual diagnosis of the disease. This article will review the evidence about the pathological significance of the visual diagnosis of endometriosis. It will analyze the aetiological factors that predispose to the disease and evidence concerning its pathogenesis. Finally, it will discuss the evidence that points to a particular epithelium being the origin of endometriosis.

Association study between epidermal growth factor receptor and epidermal growth factor polymorphisms and endometriosis in a Japanese population

OBJECTIVE

We investigated a possible association between endometriosis and polymorphisms in the genes encoding epidermal growth factor (EGF) receptor (EGFR) and EGF in a Japanese population.

METHODS

We compared the distribution of the Egfr+2073 A/T and Egf+61 G/A polymorphisms by polymerase chain reaction-restriction fragment length polymorphism analysis in 146 affected women and 181 controls.

RESULTS

No significant differences in the frequency and genotype distribution of the Egfr+2073 A/T and Egf+61 G/A polymorphisms were found between endometriosis patients with all disease stages and controls. Stratification by disease stage had no effect on the results.

CONCLUSION

The Egfr+2073 A/T and Egf+61 G/A polymorphisms are not associated with an increased risk of endometriosis in a Japanese population.

Prostaglandin E2 induces fibroblast growth factor 9 via EP3-dependent protein kinase Cdelta and Elk-1 signaling

Fibroblast growth factor 9 (FGF-9) is a potent mitogen that controls the proper development of many tissues and organs. In contrast, aberrant expression of FGF-9 also results in the evolution of many human diseases, such as cancers and endometriosis. Despite its vital function being reported, the cellular and molecular mechanisms responsible for the regulation of FGF-9 expression are mostly unknown. We report here that prostaglandin E2 (PGE2) induces expression of FGF-9, which promotes endometriotic stromal cell proliferation, through the EP3 receptor-activated protein kinase Cdelta (PKCdelta) signaling pathway. Activation of PKCdelta leads to phosphorylation of ERK1/2, and the transcription factor Elk-1 thereby promotes transcription of FGF-9. Two Elk-1 cis-binding sites located at nucleotides -1324 to -1329 and -1046 to -1051 of the human FGF-9 promoter are identified as crucial for mediating PGE2 actions. Collectively, we demonstrate, for the first time, that PGE2 can directly induce FGF-9 expression via a novel signaling pathway involving EP3, PKCdelta, and a member of the ETS domain-containing transcription factor superfamily in primary human endometriotic stromal cells. Our findings may also provide a molecular framework for considering roles for PGE2 in FGF-9-related embryonic development and/or human diseases.

Genetic approaches to the improvement of fertility traits in the pig

One of the major determinants for litter size in pigs is prenatal mortality. It occurs most frequently during the first few weeks of gestation and can be attributed to abnormalities in developmental processes during embryogenesis including trophoblastic elongation and blastocyst implantation. Improvement of litter size has been attempted by means of phenotypic selection. However, another promising approach in pursuit of this aim has been the use of genotypic information. Reproductive traits in general are well-suited for application of marker-assisted selection (MAS). The possibility of exerting selection criteria at the molecular level shortens the generation interval as the selection decision can take place early in the life of an animal. Moreover, in consideration of the sex-limited nature of reproductive traits, genotypic information allows for selection in the gender in which the trait cannot be directly observed. Accordingly, there has been considerable interest in mapping and identifying genes involved in the regulation of reproductive traits and in elucidating their expression patterns. This review offers a comprehensive, if not exhaustive, account of the efforts being made and the approaches currently used in this field. One approach has been to choose candidate genes a priori because of the physiological importance of the proteins they encode and their role in the reproduction of other mammals. The usefulness of candidate genes is then examined by association studies between genetic polymorphisms identified in the respective candidate genes and the phenotypic reproductive traits. The other approach discussed uses pre-existing or designed families for linkage analyses in order to map the location of quantitative trait loci (QTL) for the reproductive trait of interest. The results reported were not consistent among different studies but the QTL regions detected may be useful for identification of positional candidate genes in further molecular genetic studies. However, a better understanding of porcine reproduction requires that these functional genomic approaches are merged and integrated with detailed analyses of the proteome to establish linkages between predisposition and physiology.

In vivo assessment of the regulation of transforming growth factor alpha, epidermal growth factor (EGF), and EGF receptor in the human endometrium by medroxyprogesterone acetate

PURPOSE

The present study evaluated the in vivo effect of medroxyprogesterone acetate (MPA) on the localization of immunoreactive transforming growth factor alpha (TGFalpha), epidermal growth factor (EGF), and their common receptor (EGF-R) in the human endometrium.

METHODS

The study design was a randomized clinical trial enrolling 36 healthy women with regular menstrual cycles. The participants were randomly assigned into three groups: groups 1 (n = 11) and 2 (n = 17) received placebo and were submitted to endometrial biopsy during the proliferative and secretory phases of menstrual cycle, respectively; group 3 (n = 8) received MPA (10 mg/day) for 10 days followed by endometrial biopsy, which was performed during the secretory phase. Immunohistochemistry was used to localize TGFalpha, EGF, and EGF-R in the endometrial tissue.

RESULTS

TGFalpha was present markedly in the luminal and glandular epithelia but also in the periglandular stroma, with a distribution pattern similar in the three experimental groups. EGF immunostaing was equally distributed in epithelial and stromal layers of the endometrium and remained unchanged in endometrial samples from women treated with MPA compared to placebo. EGF-R was expressed only in the epithelium. The intensity of EGF-R immunostaining was higher in secretory than in proliferative endometrium and was further increased by administration of MPA (p < 0.05, chi-square test).

CONCLUSION

The present results suggest that the progestogen-induced in vivo differentiation of secretory endometrium does not require dramatic changes in the expression of EGF or TGFalpha, whereas EGF-R may be up regulated.

Steroid receptors in canine endometrial cells can be regulated by estrogen and progesterone under in vitro conditions

The expression of estrogen (ER) and progesterone receptors (PR) in the endometrium is regulated by steroid hormones. An increase in plasma estrogen leads to upregulation of the number of both steroid receptors, whereas a decrease in both receptors population is due to high concentration of plasma progesterone. To study the exact effect of different concentrations of beta-estradiol and progesterone on canine epithelial and stromal endometrial cells an in vitro model from dog uterus was developed and kept for 20 days. Material was obtained from healthy dogs, undergoing ovariohysterectomy. Endometrial epithelial and stromal cells were gained after collagenase treatment, followed by filtration steps. Electron microscopy and immunolabeling were used to study cell morphology and differentiation. Immunocytochemistry was used to determine proliferation rate (Ki-67), ER and PR status on Days 3, 8, 10, 13, and 20. Mitotic activity of both cells was stimulated with different concentrations of steroids and revealed high values until cells reached confluency. ER and PR expression in confluent layer from epithelial and stromal cells was upregulated with beta-estradiol. In addition progesterone significant downregulated both receptors population in stromal cells, whereas the reduction was less pronounced in epithelial cells. Results showed that our in vitro system is a useful tool to study the influence of beta-estradiol and progesterone on cell proliferation rate, ER and PR expression. The primary cell culture model helps to avoid experiments on living animals.

The mitogenic potential of heparin-binding epidermal growth factor in the human endometrium is mediated by the epidermal growth factor receptor and is modulated by tumor necrosis factor-alpha

Heparin-binding epidermal growth factor (HB-EGF), a member of the epidermal growth factor (EGF) family, is implicated in a variety of biological processes, including reproduction. Previous studies describe increased levels of HB-EGF in the human endometrium during the midsecretory stage of the menstrual cycle, suggesting a function for HB-EGF in implantation of the human blastocyst. Here we have investigated the expression and function of the soluble and transmembrane forms of HB-EGF in the human endometrium. We show that the expression of the transmembrane form of HB-EGF in the human endometrium is modulated according to the stage of the menstrual cycle. We present data demonstrating that both the soluble and transmembrane forms of HB-EGF induce DNA synthesis in human endometrial stromal cells. Furthermore, TNFalpha has a cooperative effect on HB-EGF, EGF, TGFalpha, and betacellulin-induced DNA synthesis in stromal cells, suggesting roles for the EGF family and TNFalpha in regeneration and maturation of human endometrium. Induction of DNA synthesis by HB-EGF and its modulation by TNFalpha in endometrial stromal cells are mediated by the EGF receptor and not the HB-EGF receptor ErbB4. Our data suggest key functions for HB-EGF, TNFalpha, and the EGF receptor in endometrial maturation, via autocrine/paracrine and juxtacrine pathways, in preparation for embryo implantation.

The reptilian oviduct: a review of structure and function and directions for future research

The reptilian oviduct is a complex organ with a variety of functions (albumen production, eggshell production, placentation, oviposition or parturition, and sperm storage), depending on the parity mode of the species in question. These functions are under complex physiological control, the details of which are far from understood. The aims of this review are to summarise the information available concerning the structure and functions of the reptilian oviduct and to highlight areas in particular need of further research.

Endometrial anomalies in women with endometriosis

Endometriotic lesions are defined by extrauterine growth of endometrial glands and stroma. Retrograde menstruation with subsequent attachment, invasion, and neovascularization are believed to give rise to the endometriotic lesions. As most women exhibit some degree of retrograde menstruation, some other unidentified factor(s) must render certain women susceptible to attachment and growth of ectopic endometrial tissue. A variety of theories have been proposed to account for this susceptibility, including genetic predisposition, aberrant immunological response, and an altered peritoneal environment. Ectopic endometriotic lesions are histologically similar to their putative eutopic precursors, yet significant biochemical differences exist between these two tissues. Less information is available regarding differences between eutopic endometrium from women with or without endometriosis. This report describes anomalies in structure, proliferation, immune components, adhesion molecules, proteolytic enzymes and inhibitors, steroid and cytokine production and responsiveness, and gene expression and protein production that have been identified in eutopic endometrium from women with endometriosis.

Regulation of plasminogen activator inhibitor 1 expression by interaction of epidermal growth factor with progestin during decidualization of human endometrial stromal cells

OBJECTIVE

During human pregnancy implantation, trophoblasts invade maternal blood vessels in a process that risks hemorrhage. Previous studies have demonstrated enhanced expression of type 1 plasminogen activator inhibitor, the primary inhibitor of fibrinolysis, during progestin-induced decidualization of estradiol-primed human endometrial stromal cells in vivo and in vitro. Decidual cell-expressed plasminogen activator inhibitor 1 is appropriately positioned to avert implantational hemorrhage. Because of the absence of estrogen or progesterone response elements from the plasminogen activator inhibitor 1 gene promoter, I posited that epidermal growth factor mediates these steroid effects and that expression of epidermal growth factor receptor in human endometrial stromal cells is under ovarian steroid control.

STUDY DESIGN

Confluent human endometrial stromal cells were exposed to vehicle control or to either estradiol (10(-8) mol/L) or medroxyprogesterone acetate (10(-7) mol/L), or both, with or without growth factors. After 40 hours the cultures were analyzed for plasminogen activator inhibitor 1 protein and messenger ribonucleic acid expressions. Immunostaining for epidermal growth factor receptor was carried out in sections of cycling and gestational endometrial tissues.

RESULTS

In the absence of steroids, epidermal growth factor did not alter plasminogen activator inhibitor 1 expression. In the absence of epidermal growth factor, estradiol and medroxyprogesterone acetate enhanced human endometrial stromal cell-secreted plasminogen activator inhibitor 1 protein levels 8-fold (n = 12; P <.001), whereas estradiol alone had no effect. Marked synergistic increases in plasminogen activator inhibitor 1 levels were elicited when epidermal growth factor was added with estradiol and medroxyprogesterone acetate (n = 12; 65-fold; P <.0001). Both transforming growth factor alpha and epidermal growth factor, which act through epidermal growth factor receptor, increased steady-state plasminogen activator inhibitor 1 messenger ribonucleic acid levels several-fold when added with estradiol and medroxyprogesterone acetate. In contrast, transforming growth factor beta, which does not activate epidermal growth factor receptor, did not elevate plasminogen activator inhibitor 1 messenger ribonucleic acid or protein levels whether added alone or with estradiol and medroxyprogesterone acetate. In correspondence with these in vitro observations, immunostaining for epidermal growth factor receptor was increased in human endometrial stromal cells undergoing decidualization in sections of secretory phase and first-trimester endometrial tissue.

CONCLUSIONS

Taken together, these in vitro and in vivo results indicate that both epidermal growth factor and progesterone receptors are required for maximal plasminogen activator inhibitor 1 expression by human endometrial stromal cells.

Epidermal growth factor regulates the transition from basal sodium absorption to anion secretion in cultured endometrial epithelial cells

The objective of this study was to investigate acute and long-term effects of epidermal growth factor (EGF) and transforming growth factor alpha (TGFalpha) on basal ion transport activity of glandular endometrial epithelial cells in primary culture. The effects of EGF on insulin-dependent regulation of Na+ transport across this epithelium was also investigated. Addition of 1.6 nM EGF or 2 nM TGFalpha to the basolateral, but not the apical, solution inhibited both basal and insulin-stimulated Na+ transport with a maximum response within 45-60 min. This effect was mimicked by the calcium ionophore ionomycin. Incubation with EGF for 4 days inhibited insulin-stimulated Na absorption in a concentration-dependent fashion with an IC(50) value of 0.3 nM. Experiments using amphotericin B-permeabilized monolayers demonstrated that EGF inhibited Na transport by decreasing apical membrane Na conductance without affecting insulin-dependent stimulation of the Na+-K+ ATPase. Addition of EGF or TGFalpha for 24 h resulted in increased basal Cl- secretion in addition to inhibition of Na absorption. The EGF-induced increase in Cl- secretion was inhibited in part by indomethacin, suggesting that long-term regulation by EGF involves stimulation of arachidonic acid synthesis and prostaglandin release. The EGF-induced increase in indomethacin-insensitive Cl- secretion was prevented by the protein synthesis inhibitor cyclohexamide, and by the DNA transcription inhibitor actinomycin D indicating that EGF-stimulated anion secretion required DNA transcription and protein synthesis. The results of these studies demonstrated that the basal transport properties of endometrial epithelial cells are differentially regulated by EGF, TGFalpha, and insulin.

Cytokine regulation of apoptotic susceptibility in a human endometrial epithelial cell line

The effects of four endometrial cytokines, transforming growth factor beta1 (TGF-beta1), interleukin-1beta (IL-1beta), epidermal growth factor (EGF), and hepatocyte growth factor (HGF), on Fas-mediated apoptosis in the human endometrial epithelial cell line, HHUA, were investigated. Although the cell growth of HHUA was not directly affected by TGF-beta1, IL-1beta, or EGF, pretreatment of HHUA with TGF-beta1, IL-1beta, or EGF enhanced Fas-mediated growth suppression and Fas-mediated DNA fragmentation in the cells. Flow cytometric analyses demonstrated that TGF-beta1, IL-1beta, and EGF did not induce Fas expression on the cell surface. These results suggest that TGF-beta1, IL-1beta, and EGF enhances apoptotic susceptibility of the cells. However, HGF inhibited Fas-mediated growth suppression and DNA fragmentation in the cells without any increase in Fas antigen expression on the cells. This finding suggests that HGF suppresses apoptotic susceptibility of the cells. From these results, we conclude that the endometrial cytokines may play a role in reshaping the endometrium after menstruation or in regulating apoptotic susceptibility in endometrial epithelium in the mid- to late-secretory period.

Endometrial-myometrial interface: relationship to adenomyosis and changes in pregnancy

The endometrial-myometrial interface (EMI) is an important region of the human uterus, which has attracted little research attention. This mucosal-muscular interface has characteristic features when compared with other similar interfaces in the human body. It lacks an intervening tissue layer and as a result, the endometrium sits directly on the myometrium rendering it vulnerable to invasion by the endometrium. Both endometrium and myometrium are sensitive to sex steroids, and their structure and function depend to a large extent on the sex hormonal milieu. Endometrium, which forms one border of the EMI, is a complex tissue consisting of several polarized microenvironments. At a cellular level, sex steroids interact with local mediators secreted by a variety of cell types and are important in maintaining the complex structure and function of the endometrium. Basal endometrium contains prominent aggregates of leukocytes that may be important in controlling local cell growth and function. Myometrium also has a distinct zonal anatomy. The recently described junctional zone differs structurally and functionally from the outer myometrium, although these functions are not yet clearly understood. Embryologically, it originates from müllerian ducts together with endometrium, whereas the outer myometrium has a non-müllerian origin. During early pregnancy, the EMI is disturbed by invading trophoblast. Alterations of myometrial intercellular matrix proteins together with expression of appropriate receptors by the trophoblast seem to regulate this unique interaction. The EMI also is disrupted in adenomyosis. The sequence of events taking place at the EMI during development of this pathology is still debated.

Expression and function of EGF-related peptides and their receptors in gynecological cancer--from basic science to therapy

EGF-related peptides and their receptors play an important, but not fully understood role, both, in epithelial physiology and pathophysiology but also in human tumor carcinogenesis and tumor behavior, respectively. Overexpression of EGF-related growth factors from normal epithelium to carcinomas has been demonstrated for several human tissues such as breast, endometrium, cervix and ovary. Additionally, the differential overexpression of EGFR or erb B-2 in various malignancies has already proven to be efficacious in stratifying patients with respect to a poor prognosis. These data suggest that EGF-related growth factors, erb B receptors or signaling proteins that function either upstream or downstream from these receptors may represent novel targets for selective tumor therapy. In the future, conventional chemotherapy regimes will ultimately be wedded to more biologically-oriented therapies. One important target for these novel therapeutic approaches in solid tumors will be the EGF-related growth factors and their receptors.

Enhanced Fas/CD95-mediated apoptosis by epidermal growth factor in human endometrial epithelial cells

Epidermal growth factor (EGF) has been reported to regulate apoptosis in various cell lineages. Throughout the menstrual cycle overexpression of the EGF receptor in the secretory epithelium and constitutive expression of EGF in all types of endometrial cells were identified by immunohistochemical study of normal human endometrial tissues. However, it is not known whether EGF also regulates endometrial apoptosis. This study examined the regulatory functions of EGF in endometrial apoptosis by using a human endometrial epithelial cell line HHUA which is susceptible to Fas-mediated apoptosis. Although EGF alone did not affect the cell growth of HHUA, EGF pretreatment of HHUA enhanced Fas-mediated growth suppression and Fas-mediated DNA fragmentation in the cells. Flowcytometric analyses demonstrated that EGF did not induce Fas expression on the cell surface while expressions of the EGF receptor were down-regulated. These results suggest that EGF may enhance apoptotic susceptibility of the endometrial epithelium, especially in the secretory epithelium.

Peritoneal endometriosis, ovarian endometriosis, and adenomyotic nodules of the rectovaginal septum are three different entities

OBJECTIVE

To review the histogenesis of peritoneal, ovarian, and rectovaginal endometriotic lesions.

DESIGN

The comparison of morphologic, morphometric, and histochemical data observed in each type of lesion.

SETTING

A university hospital department of gynecology.

PATIENT(S)

Patients complaining of infertility or pelvic pain with laparoscopically proved endometriosis.

INTERVENTION(S)

Laparoscopy was performed, and biopsy specimens from the endometriotic lesions were histologically studied.

RESULT(S)

Three types of endometriotic lesions must be considered: peritoneal, ovarian, and rectovaginal. Morphologic and morphometric data show similarities between eutopic endometrium and red peritoneal lesions, suggesting that these lesions are the first stage of early implantation of endometrial glands and stroma. After partial shedding, the red lesions regrow constantly. The shedding induces an inflammatory reaction, provoking scarification, and the lesions become black. The subsequent fibrosis leads to areas of white opacification that are inactive. The pathogenesis of ovarian endometriomas is a source of controversy. Although there seems to be a consensus concerning the invagination theory, there is still a contradiction between the implantation theory and the metaplasia theory. We recently showed that the mesothelium covering the ovary can invaginate into the ovarian cortex, pushing back the primordial follicles. The presence of mesothelial invagination in continuum with endometriotic tissue suggests that metaplastic histogenesis of ovarian endometriotic lesions occurs. Rectovaginal endometriotic nodules must be considered adenomyomas, consisting of smooth muscle with active glandular epithelium and scanty stroma. Immunocytochemical results show poor differentiation and hormonal independence of these lesions and indicate a close relation with their mesodermal müllerian origin.

CONCLUSION(S)

Peritoneal, ovarian and rectovaginal endometriotic lesions must be considered as three separate entities with different pathogeneses.

Immunology and endometriosis. Fact, artifact, or epiphenomenon?

Endometriosis is a complex and intriguing disease. If retrograde menstruation normally occurs, then why do all women not develop endometriosis? The exact prevalence of endometriosis is unknown; however, a 20% to 90% prevalency rate has been reported in women with pelvic pain and infertility. This article reviews the factors involved.

Quantitative enzyme immunoassay and semiquantitative immunohistochemistry of oestrogen and progesterone receptors in endometriotic tissue and endometrium

BACKGROUND

The capacity of different tissues to respond to steroids has been evaluated mainly according to the concentrations of oestrogen (ER) and progesterone (PR) receptors, which may be assayed either in tissue homogenates or histochemically. These two principles have been used in different studies of endometriotic tissue, giving somewhat different results, probably because the tissue is heterogeneously mixed with fibrotic tissue and blood cells to various degrees.

AIMS

To compare a quantitative and a qualitative, semiquantitative immunocytochemical assay for ER and PR in a heterogenous tissue (endometriotic) and a similar but more homogenous tissue (endometrium).

METHODS

ER and PR concentrations were measured using enzyme immunoassay (EIA) and immunocytochemistry (ICA) in the same tissue samples (endometriotic tissue from 31 women and endometrium from 19 of the same women).

RESULTS

There was a significant correlation between PR concentration (using EIA) and semiquantitation of PR using PRICA in endometrial epithelium (p = 0.028). The correlation between the two techniques for ER concentration was not significant. In endometriotic tissue no correlation was found between the two techniques for ER or PR.

CONCLUSIONS

These data show that in heterogeneous tissues like endometriotic tissue different techniques for measuring steroid receptors may produce substantially different results. The two techniques (EIA and ICA) are complementary and a combination of the two techniques might aid in determining optimal treatment.

Basic research in endometriosis

A more thorough understanding of the mechanisms associated with the cause and pathophysiology of endometriosis may help in the development of new diagnostic and therapeutic methods for the management of endometriosis. Research has begun to enhance our understanding of endometriosis by demonstrating the differences and similarites between eutopic and ectopic endometrium, and by characterizing the peritoneal environment. Animal models have been developed and validated to conduct studies that are ethically impossible in women. Recently, cell culture models, using purified populations of cells from endometriotic lesions, have provided an appropriate in vitro endometriosis model to study the language by which cells communicate; to evaluate the biochemical effects of steroids, growth factors, pharmacological agents and immunomodulatory agents on the cells; and to study the effects of endometriosis on reproduction.

Immunohistochemical studies on the expression and estrogen dependency of EGF and its receptor and C-fos proto-oncogene in the uterus and vagina of normal and neonatally estrogen-treated mice

BACKGROUND

The final target cell response to estrogen is dependent not only on the estrogen receptor, but also on autocrine/paracrine interactions with growth factors (e.g., EGF) and proto-oncogenes (e.g., c-fos). Because neonatal estrogen treatment results in permanent changes in the female mouse genital tract (permanent vaginal cornification, cervical adenosis and tumors, changed growth control mechanisms in uterus), it was of interest to study possible acute and permanent effects of such treatment on distribution and levels of EGF, its receptor (EGF-r), and c-fos and to relate such changes to morphological development and appearance of epithelial abnormalities.

METHODS

Immunohistochemical techniques using frozen sections from the uterus and vagina of neonatal and adult (ovariectomized, estradiol-treated) females, treated with olive oil or diethylstilbestrol in neonatal life.

RESULTS

A difference in stromal-epithelial distribution of EGF was demonstrated with respect to region studied (uterus, vagina) and age (neonatal, adult). EGF was localized mainly in the uterine stroma but in both vaginal epithelium and stroma (with a different pattern compared to uterus). In neonatal females, EGF occurred in both tissue components in both regions, and the distribution pattern was quite different from that in adult females. The EGF level was increased by estrogen in adult but not in neonatal females. EGF-r and c-fos occurred in both uterine epithelium and stroma and in the vaginal epithelium; levels and distribution pattern were affected by estrogen. Neonatal estrogen treatment increased the levels of uterine EGF and c-fos in adult life.

CONCLUSIONS

There are distinct developmental changes in the distribution and estrogen sensitivity of EGF. Only further studies can prove or disprove the association between the earlier reported disturbed growth control mechanisms in the uterus of adult but neonatally estrogen-treated females and the increased levels of uterine EGF and c-fos. The present results do not seem to explain mechanisms involved in the origin of neonatally estrogen-induced cervicovaginal epithelial abnormalities, nor do they explain the earlier described difference in estrogen-induced proliferative response between the uterine cervix and uterus proper.

Differential gene regulation by estrogen and progesterone in the primate endometrium

During the shift from a proliferative to a secretory endometrium in the rhesus menstrual cycle, progesterone action causes massive metabolic and structural remodelling. In order to identify genes whose expression is potentially important for the change from estrogen (E) to progesterone (P) dominance we have initiated a study of specific gene regulation using semiquantitative, reverse transcription polymerase chain reaction (RT-PCR). PolyA+ RNA was isolated from both E-dominant (days 9-13 of artificial menstrual cycles [AMCs]) and P-dominant (days 21-23) rhesus monkey endometria. The two pools of mRNA were converted to cDNA, end-ligated to double-stranded oligonucleotide adaptors and amplified by PCR using an adaptor-complementary primer. This procedure resulted in the production of E- and PcDNA template populations for cDNA-specific screening and comparative quantitation by PCR. Initial analysis showed that placental protein 14 (PP14) was P-dependent and human complement 3 (HC3) was up-regulated in E-dominant tissue, whereas the housekeeping genes B-actin and glyceraldehyde-3-phosphate dehydrogenase (G-3-PDH) were expressed at equivalent levels under E and P dominance. Expression of the E receptor (ER), P receptor (PR), epidermal growth factor receptor (EGFR) and insulin-like growth factor (IGF-I) was equivalent under E or P dominance. Expression of epidermal growth factor (EGF) and retinoblastoma (RB) was down-regulated in P-dominant tissue. Conversely IGF-1 receptor (IGF-1-R), transforming growth factor-beta 2 (TGFB-2), TGFB-2 receptor (TGFB-2-R), 17 beta-hydroxysteroid dehydrogenase (17-B-HSD) and leukemia inhibitory factor (LIF) levels were up-regulated in PcDNA. Among these factors, PP14, LIF, IGF-1-R TGFB-2 and 17-B-HSD were also detectable in PCR in a P-dependent cDNA library isolated by subtractive hybridization. These data provide evidence for hormonal regulation of specific gene products that may play important roles in the normal maturation of the primate endometrium in preparation for implantation.

Immunomodulation of rat endometriotic implant growth and protein production

PROBLEM

The immune system has been implicated in the pathophysiology of endometriosis. To determine if modulation of the immune system influences endometriotic implant growth and protein production, the following experiment was conducted.

METHOD

Female rats with surgically induced endometriosis were treated with either the immunosuppressive agent pentoxifylline (Pent; 5 mg/kg BW; N = 16) or a vehicle (N = 16) for 7 consecutive days, then killed. Twenty-four hours before death, 8 animals from each group were injected intraperitoneally with the immunostimulatory agent lipopolysaccharide (LPS; 200 micrograms/kg BW). At death, endometriotic implants were measured and protein production assessed by two-dimensional polyacrylamide gel electrophoresis.

RESULT

Pentoxifylline significantly (P < 0.001) reduced endometriotic implant size (2.15 +/- 0.65 mm2 vs. 17.13 +/- 1.98 mm2) whereas LPS was without effect (18.32 +/- 2.57 mm2 vs. 17.13 +/- 1.98 mm2). Pentoxifylline also suppressed production of a portion of the proteins that comprise the implant specific group of proteins, ENDO-2, whereas LPS induced the production of two additional ENDO-2 proteins.

CONCLUSION

Immunomodulatory agents can modulate rat endometriotic implant growth and production of implant-specific proteins.

Growth factors and growth modulators in human uterine endometrium: their potential relevance to reproductive medicine

OBJECTIVE

To provide an up-to-date, comprehensive review on the presence and regulation of growth factors (GFs), GF receptors, and GF regulatory proteins in human endometrium in an effort to understand the potential roles of these proteins in endometrial cell mitosis and differentiation and in endometrial-trophoblast interactions.

DESIGN

Relevant studies were identified through a computerized bibliographic search (MEDLINE; BRS Information Technologies, a division of Maxwell Online, Inc., McLean, VA) and through manual scanning of recent relevant journals.

RESULTS

Several GFs, their receptors, and regulatory proteins have been identified in endometrium, and cellular localization and steroid-dependence of these proteins as well as action of several growth modulators on endometrial cell function have been studied. Epidermal growth factor, transforming growth factor (TGF)-alpha, platelet-derived growth factor, insulin-like growth factors (IGFs) and their binding proteins, fibroblast growth factor (FGF), TGF-beta, colony-stimulating factor (CSF)-1, and interferon-gamma regulate mitosis of endometrial cellular components in vitro. Endothelin-1 may participate in vasoconstriction and FGF may participate in angiogenesis in this tissue in vivo. Interleukins-1 and -6 are believed to be involved in endometrial T-cell activation, and TGF-beta, CSF-1, the interleukins, and the IGFs likely mediate endometrial-trophoblast interactions. The role of tumor necrosis factor in endometrium remains uncertain.

CONCLUSIONS

Current evidence supports the thesis that GFs play a central role in cyclic mitosis and differentiation of endometrial cellular components, recruitment of macrophages in decidualizing endometrium, endometrial-trophoblast interactions, early pregnancy maintenance, tissue shedding in the absence of implantation, and endometrial functionalis regeneration.

Polypeptides synthesized and released by human endometriosis differ from those of the uterine endometrium in cell and tissue explant culture

OBJECTIVE

To identify and compare the pattern of polypeptide synthesis and release of endometriosis with that of the normal endometrium in culture.

DESIGN

Endometriosis and endometrial biopsy specimens were obtained from women presenting for a variety of diagnostic and therapeutic examinations. Specimens were cultured as isolated epithelial and stromal cells and tissue explants with L-[35S]methionine. De novo synthesized proteins were identified by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fluorography, and Western blot analysis.

RESULTS

Five major deviations in protein synthesis and secretion were noted when comparing endometriotic and endometrial culture media. Endometriosis synthesized and secreted two proteins of stromal cell origin that were not produced by normal endometrium: endometriosis protein group I (M(r) 40,000 to 55,000; pI 4.0 to 5.2) and endometriosis protein group II (M(r) 30,000 to 32,000; pI 7.0 to 9.0). Conversely, endometriosis lacked the ability to secrete or asynchronously secreted three groups of secretory phase endometrial proteins in culture: endometrial protein group I (M(r) 25,000 to 27,000; pI 4.5 to 5.5) and endometrial protein group II (M(r) 68,000 to 72,000; pI 3.0 to 3.2) were endometrial epithelial cell products whereas endometrial protein group III (M(r) 70,000; pI 5.7) was of endometrial stromal cell origin.

CONCLUSIONS

Unique characteristics in endometriosis protein synthesis and secretion as compared with the endometrium indicate biochemical dissimilarities between these tissues, which may be used to develop diagnostic markers and gain insight into the etiology and/or pathophysiology of the disease.

Estrogen induces expression of endometrial epidermal growth factor receptors before implantation

PROBLEM

Pharmacological doses of 17 beta-estradiol increase epidermal growth factor binding to uterine membranes.

METHODS

To determine whether physiological elevated E2 concentrations in the preimplantation phase of rabbits and preovulatory phase of women cause epidermal growth factor (EGF) receptor expression, we performed radioligand binding studies of endometrial membranes with [125I]-EGF.

RESULTS

Unmated rabbits revealed a binding maximum (Bmax) of 514 +/- 197 fmol/mg protein for [125I]-EGF. The Bmax values increased significantly to 1424 +/- 430 fmol/mg on day 1 and to 2244 +/- 224 fmol/mg on day 2 after mating. On day 3 the Bmax values decreased to 1409 +/- 238 fmol/mg and on days 4 to 8 the binding maxima were not significantly different from the Bmax values of unmated rabbits. In ovariectomized rabbits a significant increase of [125I]-EGF-binding could be mimicked 12 and 18 h after the intramuscular injection of estradiol (40 micrograms/kg). The estradiol-induced increase of [125I]-EGF Bmax values was blocked by the parallel application of the antiestrogen tamoxifen. Progesterone (2 mg/kg) did not influence [125I]-EGF-binding to endometrial membranes. Membrane preparations of the human endometrium from the periovulatory phase bound significantly more [125I]-EGF compared to endometrium of the early proliferative phase. The expression of EGF receptor mRNA was localized in the epithelial cells of the human endometrium by in situ hybridization technique.

CONCLUSIONS

These results provide insight into the regulation of the autocrine and paracrine factor EGF in the endometrium during the preimplantation period.

Angiogenic activity of peritoneal fluid from women with endometriosis

OBJECTIVE

To investigate the presence of angiogenic factors in peritoneal fluid (PF) and follicular fluid (FF).

DESIGN

The PF samples of 48 women with (n = 24) or without (n = 24) endometriosis were investigated. Angiogenesis was assayed using the chorioallantoic membrane of 11-day-old fertilized chicken embryos. Glass fiber prefilters impregnated with the fluids were placed on the chorioallantoic membrane.

MAIN OUTCOME MEASURE

The vascular reaction was analyzed by an independent observer after 72 hours.

RESULTS

There was a positive reaction in 58.3% of the PF from women with endometriosis and in 12.5% of the women without endometriosis. No correlation was found between the angiogenic response and the severity of endometriosis. The reaction remained after charcoal treatment of the PF. Positive reaction was found in three of six FF samples.

CONCLUSION

The PF of women with endometriosis contain more angiogenic factors than PF from women without endometriosis. This angiogenic activity could be important for the further outgrowth and progression of the lesions.

Proliferative and morphogenic changes induced by the coculture of rat uterine and peritoneal cells: a cell culture model for endometriosis

OBJECTIVE

To evaluate the proliferative and morphogenic effects induced by the coculture of uterine and peritoneal cells to establish a cell culture model for endometriosis.

DESIGN

Uterine epithelial and stromal cells and peritoneal mesothelial and subserosal cells were cocultured with homologous cell types, heterologous cell types, or as isolated populations using a bicameral chamber design.

SETTING

Department of Obstetrics and Gynecology at the University of Missouri, Columbia, Missouri.

ANIMALS

Cells isolated and purified from five mature female Sprague Dawley rats of normal reproductive status were used to establish cell cultures.

MAIN OUTCOME MEASURES

Cell proliferation (deoxyribonucleic acid synthesis) was measured by the incorporation of 3H-thymidine, and cell morphology was assessed using inverted phase-contrast microscopy.

RESULTS

Peritoneal mesothelial cells augmented proliferation and induced cellular aggregation of uterine stromal cell monolayers. Peritoneal subserosal cells amplified proliferation and induced an irregular, compacted morphology in uterine epithelial cells. The proliferation and morphology of the two peritoneal cell types was not altered by uterine cell coculture.

CONCLUSIONS

The coculture of uterine and peritoneal cells in bicameral chambers provides a tool to study the paracrine interactions of cells that comprise the endometriotic lesion. The altered proliferation and morphology of the uterine cells may be related to the histologic and biochemical asynchrony observed between uterine endometrium and ectopic endometriotic tissue in vivo and offers insight into possible mechanisms of the histogenesis of endometriosis.