A potential role for colony-stimulating factor 1 in the genesis of the early endometriotic lesion

Network meta-analysis of four common immunomodulatory therapies for the treatment of patients with thin endometrium

OBEJECTIVE

To compare the effectiveness of endometrial receptivity and pregnancy outcomes of four common immunomodulatory therapies for patients with thin endometrium.

METHOD

This systematic review and network meta-analysis using a literature search up to January 2024, to identify relevant trials comparing endometrial receptivity and pregnancy outcomes of human chorionic gonadotropin (hCG), platelet-rich plasma (PRP), infusion of granulocyte colony-stimulating factor (IG-CSF), and peripheral blood mononuclear cell (PBMC) for patients with thin endometrium. We used surface under the cumulative ranking (SUCRA) to ranked four common immunomodulatory therapies on endometrium thickness, implantation rate (IR), clinical pregnancy rate (CPR), and live birth rate (LBR). RoB2 and ROBINS-I were used to assess the certainty of evidence.

RESULTS

The pooled results of 22 studies showed that hCG (mean difference [MD]: 3.05, 95% confidence interval [CI]: 1.46-4.64) and PRP (MD: 0.98, 95% CI: 0.20-1.76) significantly increase endometrium thickness. The hCG was the best among the IG-CSF (MD = -2.56, 95% CI = -4.30 to -0.82), PBMC (MD = -2.75, 95% CI = -5.49 to -0.01), and PRP (MD = -2.07, 95% CI = -3.84 to -0.30) in increasing endometrium thickness. However, IG-CSF and PRP significantly improved IR (IG-CSF: risk ratio (RR; IG-CSF: RR = 1.33, 95% CI = 1.06-1.67; PRP: RR = 1.63, 95% CI = 1.19-2.23), and LBR (IG-CSF: RR = 1.53, 95% CI = 1.16-2.02; PRP: RR = 1.59, 95% CI = 1.08-2.36).

CONCLUSIONS

Available evidence reveals that hCG and subcutaneous or intrauterine CSF (SG-CSF) may be the best treatment options for current thin endometrium patients. However, future high-quality and large-scale studies are necessary to validate our findings.

Endoscopic sleeve gastroplasty safety profile - retrospective, single-center analysis of 222 consecutive patients including the learning curve period

Introduction

The global obesity epidemic affects over 1.9 billion adults, with an additional 650 million classified as obese. Endoscopic sleeve gastroplasty (ESG) is a type of minimally invasive endobariatric procedure. It is a less invasive alternative to laparoscopic sleeve gastrectomy (LSG). Although the effectiveness of ESG is lower, it might have a better safety profile.

Aim

To assess the safety profile of ESG and describe complications classified as grade II or higher, using the Clavien-Dindo classification, with an overview of the learning curve.

Material and methods

We included 222 patients who underwent ESG at the Endoscopic and Bariatric Surgery Center of the hospital in Brzeziny from January 2021 to October 2023. The severity of complications was evaluated based on the Clavien-Dindo classification, considering complications of grade II or higher.

Results

Among the studied group of patients, a total of 4 (1.8%) cases of perioperative bleeding into the gastrointestinal tract were recorded. One (0.5%) patient had the most severe grade IVb complication that required treatment in the Intensive Care Unit. All patients with serious adverse events (SAE) fully recovered. We did not observe an association between the learning curve, procedure duration, and the frequency or severity of postoperative complications.

Conclusions

The presented results confirm the high safety of ESG in the treatment of obesity.

Circulating Inflammatory Cytokines and Female Reproductive Diseases: A Mendelian Randomization Analysis

CONTEXT

Extensive studies have provided considerable evidence suggesting the role of inflammation in the development of female reproductive diseases. However, causality has not been established.

OBJECTIVE

To explore whether genetically determined circulating levels of cytokines are causally associated with female reproductive diseases and discover potential novel drug targets for these diseases.

METHODS

Instrumental variables (IVs) for 47 circulating cytokines were obtained from a genome-wide association study (GWAS) meta-analysis of 31 112 European individuals. Protein quantitative trait loci and expression quantitative trait loci close to genes served as our IVs. Summary data of 9 female reproductive diseases were mainly derived from GWAS meta-analysis of the UK biobank and FinnGen. We elevated the association using the Wald ratio or inverse variance-weighted Mendelian randomization (MR) with subsequent assessments for MR assumptions in several sensitivity and colocalization analyses. We consider a false discovery rate <0.05 as statistical significance in MR analyses. Replication studies were conducted for further validation, and phenome-wide association studies were designed to explore potential side effects.

RESULTS

Our results indicated that high levels of macrophage colony-stimulating factor (MCSF), growth-regulated oncogene-alpha (GROα), and soluble intercellular adhesion molecule-1 were associated with increased risks of endometriosis, female infertility, and pre-eclampsia, respectively. High platelet-derived growth factor-BB (PDGF-BB) levels that reduced the risk of ovarian aging were also supported. Replication analysis supported the relationship between GROα and female infertility, and between MCSF and endometriosis.

CONCLUSION

We identified 4 correlated pairs that implied potential protein drug targets. Notably, we preferred highlighting the value of PDGF-BB as a drug target for ovarian aging, and MCSF as a drug target for endometriosis.

How do pre-pregnancy endometrial macrophages contribute to pregnancy?

Macrophages are professional phagocytes with a wide distribution in all tissues throughout the body. Macrophages play a crucial role in homeostasis and numerous physiological processes beyond innate and adaptive immunity, including cellular debris removal, metabolic regulation, tissue repair, and tissue remodeling. Uterine macrophages are a heterogeneous and highly plastic subset of immune cells regulated by the local microenvironment and, in addition to their anti-inflammatory and anti-infective functions, support the establishment and maintenance of pregnancy. Comprehensive reviews have summarized the role of decidual macrophages during pregnancy. However, the distribution of macrophages in the endometrium prior to pregnancy, their functional remodeling, and the knock-on effects on subsequent pregnancies have not been elucidated. In this review, we focus on 1) how the phenotypes of endometrial macrophages and their interactions with other endometrial cells indicate or contribute to the subsequent pregnancy, 2) the adaptive switching of endometrial macrophages during the initial establishment of pregnancy, 3) and the pregnancy complications and pregnancy-related disorders associated with endometrial macrophages.

The effectiveness of immunomodulatory therapies for patients with repeated implantation failure: a systematic review and network meta-analysis

This meta-analysis analyzed the clinical pregnancy outcomes of repeated implantation failure (RIF) patients treated with immunomodulatory therapies. Publications (published by August 16, 2021) were identified by searching the PubMed, Embase, and Web of Science databases. The quality of the studies was evaluated with the Cochrane bias risk assessment tool, and a network meta-analysis was performed with Stata 14.0. The outcomes were clinical pregnancy rate (CPR), live birth rate (LBR), and implantation rate (IR). The results of our network meta-analysis of 16 RCTs (including 2,008 participants) show that PBMCs, PRP, and SC-GCSF can significantly improve the CPR compared with LMWH (PBMCs: OR 2.15; 95% CI 1.21-3.83; PRP: OR 2.38; 95% CI 1.08-5.24; SC-GCSF: OR 2.46; 95% CI 1.05-5.72). The LBR of PRP was significantly higher than those of IU-GCSF (OR 3.81; 95% CI 1.22-11.86), LMWH (OR 4.38; 95% CI 1.50-12.90), and intralipid (OR 3.85; 95% CI 1.03-14.29), and the LBR of PBMCs was also significantly better than that of LMWH (OR 2.35; 95% CI 1.14-4.85). Furthermore, PRP treatment significantly improved the IR compared with LMWH treatment (OR 2.81; 95% CI 1.07-7.4). The limited evidence from existing RCTs suggests that PBMCs and PRP are the best therapeutic options for RIF patients. However, owing to the quantity limitation, more top-quality research is required to obtain additional high-level evidence.

Cell-based therapy in thin endometrium and Asherman syndrome

Numerous treatment strategies have so far been proposed for treating refractory thin endometrium either without or with the Asherman syndrome. Inconsistency in the improvement of endometrial thickness is a common limitation of such therapies including tamoxifen citrate as an ovulation induction agent, acupuncture, long-term pentoxifylline and tocopherol or tocopherol only, low-dose human chorionic gonadotropin during endometrial preparation, aspirin, luteal gonadotropin-releasing hormone agonist supplementation, and extended estrogen therapy. Recently, cell therapy has been proposed as an ideal alternative for endometrium regeneration, including the employment of stem cells, platelet-rich plasma, and growth factors as therapeutic agents. The mechanisms of action of cell therapy include the cytokine induction, growth factor production, natural killer cell activity reduction, Th17 and Th1 decrease, and Treg cell and Th2 increase. Since cell therapy is personalized, dynamic, interactive, and specific and could be an effective strategy. Despite its promising nature, further research is required for improving the procedure and the safety of this strategy. These methods and their results are discussed in this article.

Endometriosis in the Mouse: Challenges and Progress Toward a ‘Best Fit’ Murine Model

Endometriosis is a prevalent gynecologic condition associated with pelvic pain and infertility characterized by the implantation and growth of endometrial tissue displaced into the pelvis via retrograde menstruation. The mouse is a molecularly well-annotated and cost-efficient species for modeling human disease in the therapeutic discovery pipeline. However, as a non-menstrual species with a closed tubo-ovarian junction, the mouse poses inherent challenges as a preclinical model for endometriosis research. Over the past three decades, numerous murine models of endometriosis have been described with varying degrees of fidelity in recapitulating the essential pathophysiologic features of the human disease. We conducted a search of the peer-reviewed literature to identify publications describing preclinical research using a murine model of endometriosis. Each model was reviewed according to a panel of ideal model parameters founded on the current understanding of endometriosis pathophysiology. Evaluated parameters included method of transplantation, cycle phase and type of tissue transplanted, recipient immune/ovarian status, iterative schedule of transplantation, and option for longitudinal lesion assessment. Though challenges remain, more recent models have incorporated innovative technical approaches such as in vivo fluorescence imaging and novel hormonal preparations to overcome the unique challenges posed by murine anatomy and physiology. These models offer significant advantages in lesion development and readout toward a high-fidelity mouse model for translational research in endometriosis.

IL-34 and CSF-1, deciphering similarities and differences at steady state and in diseases

Although IL-34 and CSF-1 share actions as key mediators of monocytes/macrophages survival and differentiation, they also display differences that should be identified to better define their respective roles in health and diseases. IL-34 displays low sequence homology with CSF-1 but has a similar general structure and they both bind to a common receptor CSF-1R, although binding and subsequent intracellular signaling shows differences. CSF-1R expression has been until now mainly described at a steady state in monocytes/macrophages and myeloid dendritic cells, as well as in some cancers. IL-34 has also 2 other receptors, protein-tyrosine phosphatase zeta (PTPζ) and CD138 (Syndecan-1), expressed in some epithelium, cells of the central nervous system (CNS), as well as in numerous cancers. While most, if not all, of CSF-1 actions are mediated through monocyte/macrophages, IL-34 has also other potential actions through PTPζ and CD138. Additionally, IL-34 and CSF-1 are produced by different cells in different tissues. This review describes and discusses similarities and differences between IL-34 and CSF-1 at steady state and in pathological situations and identifies possible ways to target IL-34, CSF-1, and its receptors.

Autocrine Production of Interleukin-34 Promotes the Development of Endometriosis through CSF1R/JAK3/STAT6 signaling

Interleukin (IL)-34 plays a critical role in cell proliferation, differentiation, apoptosis, angiogenesis, inflammation and immunoregulation. Numerous diseases can be attributed to the dysregulation of IL-34 signaling. This study was performed to investigate the function of IL-34 in the pathogenesis of endometriosis. Firstly, by enzyme linked immunoabsorbent assay, we found that IL-34, VEGF, MMP-2 and MMP-9 were increased in the sera of patients with endometriosis. Secondly, exposure to IL-34 promoted the proliferation, migration and invasion of eutopic endometrial stromal cells (ESCs). Additionally, stimulation with IL-34 up-regulated colony-stimulating factor 1 receptor (CSF1R), p-JAK3, p-STAT6, VEGF, MMP-2 and MMP-9 in these eutopic ESCs. Treatment with AS1517499, an inhibitor of STAT6, remarkably abrogated the alterations induced by IL-34. A Chromatin immunoprecipitation (ChIP) assay demonstrated binding of STAT6 to the IL-34 promoter, further implicating STAT6 in IL-34 signaling. Notably, reverse results were obtained in ectopic ESCs with the application of an IL-34 neutralizing antibody. In vivo, AS1517499 suppressed the maintenance of endometriosis lesions in rats. In summary, autocrine production of IL-34, mediated by STAT6, promoted the development of endometriosis in vitro and in vivo through the CSF1R/JAK3/STAT6 pathway. Our research reveals the function of IL-34 in endometriosis, which may provide insight into novel therapeutic strategies for endometriosis.

Embryo transfer strategy and therapeutic options in infertile patients with thin endometrium: a systematic review

Human endometrium has a key role in implantation process. The measurement of endometrial thickness is the most commonly used in clinical practice. Managing patients with thin endometrium still represents a major challenge for clinicians. The objective of this systematic review was to investigate all available interventions to improve endometrial thickness (EMT) in women with history of thin endometrium undergoing fresh or frozen-thawed embryo transfers (ET). We performed a comprehensive search of relevant studies from January 1978 to February 2018. The different strategies were categorized as hormonal, vascular, and growth factor approaches and specifically analyzed according to the type of ET. Thirty-one studies were included. Overall, quality of the evidence ranged from very low to moderate, with only few randomized controlled trials that support the use of either GnRH analogues in fresh ET or sildenafil in frozen ET for enhancing endometrial growth. Besides, intensified estradiol administration is a common approach that might improve EMT in frozen ET. The present review evidences the paucity of reliable data regarding the efficiency of different interventions aiming at increasing EMT before fresh or frozen-thawed ET. Robust and high-quality randomized controlled trials are still needed before guidelines can be established.

G-CSF and stem cell therapy for the treatment of refractory thin lining in assisted reproductive technology

PURPOSE

The study aims to describe two promising therapeutic options for resistant "thin" endometrium in fertility treatment: granulocyte colony-stimulating factor (G-CSF) and stem cell therapy.

METHODS

A review of the scientific literature related to patients with thin endometrium undergoing fertility treatment.

RESULTS

Sufficient endometrial growth is fundamental for embryo implantation. Whether idiopathic or resulting from an underlying pathology, a thin endometrium of <7 mm is associated with lower probability of pregnancy; however, no specific thickness excludes the occurrence of pregnancy. We specifically reviewed two relatively new treatment options for resistant thin lining: intrauterine G-CSF and stem cell therapy. The majority of the reviewed trials showed a significant benefit for intrauterine G-CSF infusion in improving endometrial thickness and pregnancy rates. Early results of stem cell therapy trials seem promising.

CONCLUSIONS

EMT <7 mm is linked to lower probability of pregnancy in assisted reproductive technology. Intrauterine G-CSF infusion appears to be a potentially successful treatment option for resistant cases, while stem cell therapy seems to be a promising new treatment modality in severely refractory cases.

Co-culture with macrophages enhances the clonogenic and invasion activity of endometriotic stromal cells

OBJECTIVE

To study the effect on endometrial and endometriotic cells after co-culture with macrophages, using clonogenic, invasion and self-renewal assays.

MATERIALS AND METHODS

Peripheral blood samples, endometrium and endometriotic tissues were collected. Autologous macrophages were co-cultured with endometrial and endometriotic cells. The number of colony-forming units (CFU), invasiveness and self-renewal activity after co-culture with macrophages were determined. The cytokine level of colony-stimulating factor-1 (CSF-1) from macrophages with and without endometriosis was compared.

RESULTS

Co-culture with macrophages significantly increased the clonogenic and invasion ability of endometriotic stromal cells in vitro. Colony-stimulating factor-1 (CSF-1) was up-regulated in endometriotic macrophages conditioned medium when compared to those without the disease.

CONCLUSIONS

These data suggest that macrophages may increase the proliferation and invasion activity of stromal clonogenic cells in women with endometriosis.

Whether G-CSF administration has beneficial effect on the outcome after assisted reproductive technology? A systematic review and meta-analysis

BACKGROUND

Previous studies have explored the effect of granulocyte colony stimulating factor (G-CSF) administration on the outcome of assisted reproductive technology (ART), and came into controversial conclusions. The present meta-analysis aims to assess whether G-CSF administration has beneficial effect on the outcome after ART.

METHOD

The electronic databases Pubmed, Embase and Google Scholar were searched up to May 2016. Articles that studied the effect of G-CSF administration on the outcome after ART were included in the present meta-analysis. Odds ratio (OR) with 95 % confidence interval (95 % CI) were calculated to assess the effect of G-CSF administration on the outcome after ART. The outcomes of interest were implantation rate (IR) and pregnancy rate (PR).

RESULTS

Four cohort studies with 1101 embryos transplantation assessed the effect of G-CSF administration on IR and 6 studies with 621 cycles assessed the role of G-CSF administration in PR. Meta-analysis did not found an increased embryo IR in G-CSF administration cycles [OR 1.59 (95 % CI 0.74-3.41). whereas the PR with G-CSF administration was significantly higher compared with cases without G-CSF administration [OR 2.03 (95 % CI 1.19-3.46)]. Additionally, we found that G-CSF administrated subcutaneously resulted in significantly higher PR [OR 3.12 (95 % CI 1.67-5.81)] and IR [OR 2.82 (95 % CI 1.29-6.15)] compared with control group, whereas G-CSF administrated via local uterine infusion had no beneficial effect on the PR [OR 1.42 (95 % CI 0.91-2.24)] and IR [OR 1.10 (95 % CI 0.76-1.60)] after ART.

CONCLUSIONS

G-CSF administration may have beneficial effect on clinical pregnancy outcome after ART. Subcutaneous injection may be an optimal route of G-CSF administration. Further cohort studies are required to explore the mechanisms undergone the effect and investigate the best route and dose of G-CSF administration.

Impaired Development of Early Endometriotic Lesions in CD44 Knockout Mice

Previous studies have shown endometrial cell (EC) CD44 and peritoneal mesothelial cell (PMC)-associated hyaluronan (hyaluronic acid [HA]) are involved in the attachment of endometrial stroma and epithelial cells to peritoneal mesothelium. Here we assess the CD44-HA interaction in the formation of the early endometriotic lesion using CD44(-/-) (knockout) mice. Using an established murine model and crossover technique, endometrial tissue from donor mice (wild type [WT] and CD44(-/-)) was used to induce endometriosis in recipient mice (WT and CD44(-/-)). Endometriotic lesions were visualized by fluorescent microscopy and confirmed by hematoxylin and eosin staining. Early endometriotic lesions were decreased when CD44(-/-) endometrium was placed in WT recipients and when WT endometrium was placed in CD44(-/-) recipients (P = .002). Early endometriotic lesions were also significantly decreased when both peritoneal and endometrial tissues lacked CD44 expression (P < .01). These studies demonstrate that both EC and PMC CD44 play a role in the development of early endometriotic lesion.

Estradiol is a critical mediator of macrophage-nerve cross talk in peritoneal endometriosis

Endometriosis occurs in approximately 10% of women and is associated with persistent pelvic pain. It is defined by the presence of endometrial tissue (lesions) outside the uterus, most commonly on the peritoneum. Peripheral neuroinflammation, a process characterized by the infiltration of nerve fibers and macrophages into lesions, plays a pivotal role in endometriosis-associated pain. Our objective was to determine the role of estradiol (E2) in regulating the interaction between macrophages and nerves in peritoneal endometriosis. By using human tissues and a mouse model of endometriosis, we demonstrate that macrophages in lesions recovered from women and mice are immunopositive for estrogen receptor β, with up to 20% being estrogen receptor α positive. In mice, treatment with E2 increased the number of macrophages in lesions as well as concentrations of mRNAs encoded by Csf1, Nt3, and the tyrosine kinase neurotrophin receptor, TrkB. By using in vitro models, we determined that the treatment of rat dorsal root ganglia neurons with E2 increased mRNA concentrations of the chemokine C-C motif ligand 2 that stimulated migration of colony-stimulating factor 1-differentiated macrophages. Conversely, incubation of colony-stimulating factor 1 macrophages with E2 increased concentrations of brain-derived neurotrophic factor and neurotrophin 3, which stimulated neurite outgrowth from ganglia explants. In summary, we demonstrate a key role for E2 in stimulating macrophage-nerve interactions, providing novel evidence that endometriosis is an estrogen-dependent neuroinflammatory disorder.

Macrophage migration inhibitory factor is involved in ectopic endometrial tissue growth and peritoneal-endometrial tissue interaction in vivo: a plausible link to endometriosis development

Pelvic inflammation is a hallmark of endometriosis pathogenesis and a major cause of the disease's symptoms. Abnormal immune and inflammatory changes may not only contribute to endometriosis-major symptoms, but also contribute to ectopic endometrial tissue growth and endometriosis development. A major pro-inflammatory factors found elevated in peritoneal fluid of women with endometriosis and to be overexpressed in peritoneal fluid macrophages and active, highly vascularized and early stage endometriotic lesions, macrophage migration inhibitory factor (MIF) appeared to induce angiogenic and inflammatory and estrogen producing phenotypes in endometriotic cells in vitro and to be a possible therapeutic target in vivo. Using a mouse model where MIF-knock out (KO) mice received intra-peritoneal injection of endometrial tissue from MIF-KO or syngeneic wild type (WT) mice and vice versa, our current study revealed that MIF genetic depletion resulted in a marked reduction ectopic endometrial tissue growth, a disrupted tissue structure and a significant down regulation of the expression of major inflammatory (cyclooxygenease-2), cell adhesion (αv and β3 integrins), survival (B-cell lymphoma-2) and angiogenic (vascular endothelial cell growth) factorsrelevant to endometriosis pathogenesis, whereas MIF add-back to MIF-KO mice significantly restored endometriosis-like lesions number and size. Interestingly, cross-experiments revealed that MIF presence in both endometrial and peritoneal host tissues is required for ectopic endometrial tissue growth and pointed to its involvement in endometrial-peritoneal interactions. This study provides compelling evidence for the role of MIF in endometriosis development and its possible interest for a targeted treatment of endometriosis.

Towards an understanding of the molecular mechanism of endometriosis: unbalancing epithelial-stromal genetic conflict

OBJECTIVES

Despite the high incidence of endometriosis, the etiology is poorly understood. Much work has been carried out to elucidate the genetic basis of endometriosis owing to the advent of genomic analysis and new network-based analysis methods.

METHODS

This article reviews the English literature for (epi)genome-wide profiling and association studies on the pathogenesis and pathophysiology of endometriosis.

RESULTS

The characteristic 82 up- and 45 down-regulated unique genes in endometriosis included genes encoding cell cycle, growth factors, signal transduction, transcription factors, hormones, cytokines, chemokines and (pro)inflammation, proteases, cell adhesion and motility, stress response and detoxification, immune response, metabolism and others. There appear to be at least two types of genes: some genes (n = 50) may evolve mainly for the benefit of the endometrial growth, and the other genes (n = 55) evolve as a protective mechanism for the endometrial decidualization. The present review has shed new light on the overlapping genetic signatures between endometriosis development and decidualization process.

CONCLUSION

In conclusion, insufficient decidualization due to unbalancing epithelial-stromal genetic conflict may result in future endometriosis.

Use of granulocyte colony-stimulating factor for the treatment of thin endometrium in experimental rats

Granulocyte colony-stimulating factor (G-CSF) induces stem cells to mobilize to the injury site, which have beneficial effect on tissue repair. The aim of this study was to investigate the effect of G-CSF on the thin endometrium in rat models. In the present study, rats with thin endometrium were divided into 4 groups (experimental group I: administrated with G-CSF (40 µg/kg/d) 4-6 hours post-modeling; control group I: administrated with saline 4-6 hours post-modeling; experimental group II: administrated with G-CSF (40 µg/kg/d) 12 days post-modeling; control group II: administrated with saline 12 days post-modeling. The agentia was given once daily and last for 5 days. Endometrial morphology was analyzed by Hematoxylin-Eosin staining, and the regeneration of endometrial cells was evaluated by immunohistochemistry and western-blot with cytokeratin and vimentin. We found that endometrial thickness and morphology presented a significant difference between experimental groups and control groups. No matter when we start with G-CSF, there was a significantly thicker endometrium and stronger expression of cytokeratin/vimintin in the experimental groups compared with the control groups (P<0.01). There were significant thicker endometrial lining and stronger expression of cytokeratin/vimintin in experimental group I than that of experimental group II (P<0.05), but there was no difference in the endometrial lining and the expression of cytokeratin/vimintin between the two control groups (P>0.05). In conclusion, G-CSF can promote the regeneration of endometrial cells in animal research, especially when the G-CSF was administrated earlier.

Raf-1, a potential therapeutic target, mediates early steps in endometriosis lesion development by endometrial epithelial and stromal cells

Endometriosis is a hormone-sensitive gynecological disorder characterized by the benign growth of endometrial-like tissue in the pelvic cavity. Endometriotic lesions composed of endometrial stromal cells (ESC) and glandular epithelial cells (EEC) are thought to arise from menstrual endometrial tissue reaching the pelvic cavity via retrograde menstruation. The cause of endometriotic lesion formation is still not clear. Recent evidence suggest that cytokines may play a role in the early development of endometriosis lesions. Because cytokines and growth factors signal via the v-raf-1 murine leukemia viral oncogene homolog 1 (Raf-1) kinase pathway, we have examined the role of Raf-1 in early steps of endometriosis lesion formation, specifically attachment of endometrial cells to peritoneal mesothelial cells (PMC) and invasion of endometrial cells through PMC (trans-mesothelial invasion). Raf-1 antagonist GW5074 decreased attachment to PMC and trans-mesothelial invasion by primary EEC and ESC. Raf-1 also mediated TGFβ-induced trans-mesothelial invasion by the established, low-invasive EEC line EM42. TGFβ treatment of EEC resulted in Raf-1 phosphorylation at S338 and phosphorylation of ERK, suggesting that TGFβ activates Raf-1 signaling in these cells. GW5074 had little effect on ESC proliferation but inhibited EEC growth significantly under reduced serum conditions. Antagonizing Raf-1 activity and expression via GW5074 and specific Raf-1 small interfering RNA, respectively, did not alter EEC resistance to growth inhibition by TGFβ. Raf-1 inhibition blocked induction of EEC growth by epidermal growth factor. Our data suggest that Raf-1 may mediate pathologic steps involved in early endometriosis lesion formation and may be a mediator of TGFβ and epidermal growth factor actions in endometriosis.

FMS Kinase Inhibitors: Current Status and Future Prospects

FMS, first discovered as the oncogene responsible for Feline McDonough Sarcoma, is a type III receptor tyrosine kinase that binds to the macrophage or monocyte colony-stimulating factor (M-CSF or CSF-1). Signal transduction through that binding results in survival, proliferation, and differentiation of monocyte/macrophage lineage. Overexpression of CSF-1 and/or FMS has been implicated in a number of disease states such as the growth of metastasis of certain types of cancer, in promoting osteoclast proliferation in bone osteolysis, and many inflammatory disorders. Inhibition of CSF-1 and/or FMS may help treat these pathological conditions. This article reviews FMS gene, FMS kinase, CSF-1, IL-34, and their roles in bone osteolysis, cancer biology, and inflammation. Monoclonal antibodies, FMS crystal structure, and small molecule FMS kinase inhibitors of different chemical scaffolds are also reviewed.

Increased expression of macrophage colony-stimulating factor and its receptor in patients with endometriosis

OBJECTIVE

To investigate the expression and regulation of colony-stimulating factor 1 (CSF-1) and its receptor, C-FMS, in endometriosis.

DESIGN

In vivo and vitro study.

SETTING

University-based academic medical center.

PATIENT(S)

Reproductive-age women undergoing surgery for benign conditions.

INTERVENTION(S)

Peritoneal and endometrial tissue samples were obtained.

MAIN OUTCOME MEASURE(S)

CSF-1 and C-FMS expression.

RESULT(S)

Significantly higher CSF-1 levels were found in peritoneal fluid of patients with endometriosis compared with control subjects. Ectopic endometriotic tissue had 3.5-fold and 1.7-fold increases in CSF-1 and C-FMS expression, respectively, compared with eutopic tissue. Coculture of endometrial cells from either established cell lines or patient samples with peritoneal mesothelial cells (PMCs) led to increased expression of CSF-1 and C-FMS. A higher but nonsignificant increase in levels of C-FMS and CSF-1 was found in cocultures of endometrial epithelial cells from patients with endometriosis compared with those without endometriosis.

CONCLUSION(S)

Increased CSF-1 levels may contribute to endometriosis lesion formation and progression. Elevation in CSF-1 after coculture of endometrial cells with PMCs suggests that endometrial tissue may be a source of peritoneal CSF-1. Increased C-FMS expression in endometrial cells from women with endometriosis cocultured with PMCs suggests that endometrial tissue involved in lesion formation is highly responsive to CSF-1 signaling.

Colony-stimulating factor-1 exerts direct effects on the proliferation and invasiveness of endometrial epithelial cells

Although macrophage colony-stimulating factor (CSF-1) has been suggested to play a role in maintaining the chronic inflammatory response in endometriosis, our data suggest that CSF-1 may also play a role in early endometriosis lesion formation. We have shown that CSF-1, in an autocrine fashion, has a direct effect on endometrial epithelial cell proliferation and attachment to peritoneal mesothelial cells, early steps in endometriosis lesion formation on the peritoneum.

Induction of endometrial epithelial cell invasion and c-fms expression by transforming growth factor beta

Transforming growth factor beta 1 (TGF-beta1) levels are increased in the peritoneal fluid of endometriosis patients, and endometrial cells express TGF-beta signaling components; however, little is known regarding the role of TGF-beta in endometriosis. Our objective was to examine the effects of TGF-beta1 on (i) the expression of macrophage colony-stimulating factor receptor encoded by the c-fms gene, (ii) transmesothelial invasiveness of endometrial cells, (iii) cellular proliferation and (iv) attachment to peritoneal mesothelial cells (PMCs). Effects of TGF-beta1 on c-fms mRNA expression were determined by real-time RT-PCR and c-fms cell-surface expression by flow cytometry. Effects of TGF-beta1 on the invasiveness of the immortalized endometrial epithelial cell (EEC) line EM42 and primary EECs were examined using a three-dimensional in vitro system modeling the peritoneum. Cellular proliferation and attachment to PMCs were also examined using established techniques. TGF-beta1 had little or no effect on cellular proliferation and endometrial cell attachment to PMCs. TGF-beta1 significantly induced the expression of c-fms mRNA and c-fms cell-surface expression. TGF-beta1 enhanced transmesothelial invasion by EM42 cells and EECs. Antagonists of TGF-beta1 signaling significantly inhibited both the induction of c-fms expression and cellular invasiveness, suggesting that additional studies are warranted to assess the therapeutic potential of TGF-beta antagonists in endometriosis.