Vascular endothelial growth factor pathway in endometriosis: genetic variants and plasma biomarkers.

OBJECTIVE: To study single nucleotide polymorphisms (SNPs) involved in angiogenesis (VEGF, PLGF, VEGFR1, VEGFR2, HIF-1α) and plasma levels of the corresponding proteins (VEGF, PLGF, sVEGFR1, sVEGFR2) in women with and without endometriosis. DESIGN: Allele frequencies of vascular endothelial growth factor (VEGF) pathway SNPs and plasma levels of the corresponding proteins were investigated in patients with endometriosis and in controls. SETTING: University hospital. PATIENT(S): Samples of DNA from 1,931 Caucasian patients were included (1,109 patients with endometriosis and 822 controls). An additional study group included 973 DNA samples from volunteers, self-reported to be healthy without laparoscopic evaluation. INTERVENTION(S): Women who underwent a laparoscopy for subfertility and/or pain and healthy volunteers without laparoscopic evaluation. MAIN OUTCOME MEASURE(S): Functional SNPs of the VEGF, VEGFR1, VEGFR2, HIF-1α genes and Hap Map tagging SNPs of the PLGF gene were genotyped by using iPLEX technology on a Sequenom MassArray and TaqMan SNP Genotyping Assay. The VEGF levels were determined in ethylenediaminetetraacetic acid plasma samples by using Bio-Plex Protein Array System. PLGF, sVEGFR1, and sVEGFR2 levels were measured in ethylenediaminetetraacetic acid plasma samples by using ELISA Quantikine kits. RESULT(S): A significant association was found between the rs2268613 polymorphism in the PLGF gene and PLGF plasma levels. In all study subjects, women with the AA variant of the rs2268613 PLGF gene had significantly lower PLGF plasma levels (median [interquartile range] 9.36 [8.19-10.43] pg/mL) than those with the AG variant (12.1 [11.81-20.84] pg/mL; P(a)=.0085, P(b)=.04), both before and after multiple testing. Plasma levels of VEGF were elevated in endometriosis patients (especially in minimal-mild endometriosis during the menstrual cycle phase) compared with laparoscopic controls but had a moderate diagnostic performance (area under the curve, 0.73) in this discovery dataset. At a cut-off plasma level of VEGF >3.88 pg/mL, minimal-mild stages of endometriosis were diagnosed with a sensitivity of 74% and a specificity of 80% during the menstrual phase of cycle. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing. CONCLUSION(S): Genetic variants in the PLGF rs2268613 gene may influence plasma levels of the corresponding protein. Plasma levels of VEGF were elevated in endometriosis patients compared with controls. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.

c-Jun NH2-terminal kinase inhibitor bentamapimod reduces induced endometriosis in baboons: an assessor-blind placebo-controlled randomized study.

OBJECTIVE: To test the hypothesis that the c-Jun NH2-terminal kinase (JNK) inhibitor (JNKI) bentamapimod (AS602801/PGL5001) can reduce induced endometriosis in baboons. DESIGN: Prospective randomized placebo-controlled study. SETTING: Nonhuman primate research center. ANIMAL(S): Twenty baboons each underwent four laparoscopies. Initial screening laparoscopy (L1) was followed after one rest cycle by an endometriosis-induction laparoscopy (L2). Fifty days after L2, the baboons were randomized just before staging laparoscopy (L3). Treatment lasted for 60 days, followed by a post-treatment staging laparoscopy (L4). INTERVENTION(S): Randomization before a 60-day treatment in four groups: daily placebo (n = 5), daily oral administration of 20 mg/kg JNKI (n = 5), concomitant daily oral administration of 20 mg/kg JNKI and 10 mg medroxyprogesterone acetate (MPA; n = 5), or subcutaneous administration of 3 mg cetrorelix every 3 days (n = 5). MAIN OUTCOME MEASURE(S): Type, surface area and volume of endometriotic lesions, and revised American Society for Reproductive Medicine score and stage were recorded during L3 and L4. Menstrual cycle length and serum hormonal concentration were recorded before and after treatment. RESULT(S): Compared with placebo, treatment with JNKI, JNKI + PMA, or cetrorelix resulted in lower total surface area and volume of endometriotic lesions. Remodeling of red active lesions into white lesions was observed more frequently in baboons treated with JNKI + MPA than in baboons treated with JNKI only. Menstrual cycle length and serum hormonal concentration were similar between placebo and JNKI groups. CONCLUSION(S): JNKI alone was as effective as JNKI + MPA or cetrorelix in reducing induced endometriosis in baboons, but without severe side effects or effect on cycle length or serum reproductive hormones.

Menstrual endometrial supernatant may induce stromal endometriosis in baboons.

We tested the hypothesis that endometriosis can be induced in baboons more successfully by intra-pelvic injection of the pellet of menstrual endometrium when compared to its supernatant. Menstrual endometrium, separated into pellet (n = 5) and supernatant fractions ( n = 8), or phosphate buffered saline (1 ml, n = 7, controls) was injected laparoscopically into the pelvis. During laparoscopy 25 days later, the number (ρ = 0.027) and surface area (ρ <0.0001) of endometriosis-like lesions were significantly higher in the pellet group, than in the supernatant group, or in the control group. Histological typical endometriosis was present only in the endometrial pellet group (1/15), whereas stromal endometriosis was observed in both the pellet group (6/15), and the supernatant group (6/20). Peritoneal endometrial like glands were observed in both the endometrial pellet group (3/15), and in the supernatant group (1/20). In conclusion, we confirmed our hypothesis that endometriosis can be induced in baboons more successfully by intrapelvic injection of the pellet of menstrual endometrium when compared to its supernatant.

Inhibition of type 1 17ß-hydroxysteroid dehydrogenase impairs the synthesis of 17ß-estradiol in endometriosis lesions.

CONTEXT: Endometriosis affects 10% of the women before menopause and has important personal, professional, and societal economic burdens. Because current medical treatments are aimed at reducing the symptoms only, novel therapeutic targets should be identified. Endometriosis is estrogen dependent and in some patients the endometriosis tissue is able to produce estrogens in an autocrine/paracrine manner. In a number of patients, this is the consequence of the high local activity of the 17ß-hydroxysteroid-dehydrogenases (17ß-HSDs), enzymes able to generate active estrogens from precursors with low activity. OBJECTIVE: The objective of the study was to identify the 17ß-HSD(s) responsible for the high local generation of estrogens in endometriosis and test the possibility to inhibit these enzymes for therapeutic purposes. DESIGN: The expression of different 17ß-HSDs involved in the estrogen metabolism was assessed by real-time PCR in eutopic and ectopic tissue from endometriosis patients (n=14). These biopsies had previously confirmed unbalanced local 17ß-HSD activity, which caused high estrogen generation. The possibility to block the synthesis of estrogens by one inhibitor specific for type 1 17ß-HSD was assessed by HPLC in tissue lysates from endometriosis tissues (n=27). RESULTS: In all but one of the patients, a high type 1 17ß-HSD level is associated with the unbalanced metabolism of estrogens, leading to higher estrogen synthesis in endometriosis than in the endometrium inside the uterus. Inhibition of type 1 17ß-HSD restores to various extents, depending on the patient, the correct metabolism. In 19 of 27 patients analyzed (70%), the 17ß-HSD type 1 inhibitor decreased the generation of 17ß-estradiol by greater than 85%. CONCLUSIONS: Inhibition of 17ß-HSD type 1 can be a potential future treatment option aimed at restoring the correct metabolic balance of estrogens in endometriosis patients with increased local 17ß-HSD type 1 enzyme activity.

Analysis of common variations in tumor-suppressor genes on chr1p36 among Caucasian women with endometriosis.

OBJECTIVE: Epidemiological data indicate that endometriosis increases the risk of epithelial ovarian cancer (EOC), but the mechanism of cancer transition is unknown. Results from genome-wide association studies (GWAS) and transcriptome sequencing have demonstrated that genes located in the 1p36 region are important in both endometriosis and endometriosis-associated cancer development. Therefore, we tested the hypothesis that SNPs in two tumor-suppressor genes (CHD5 and ARID1A) in the 1p36 region are associated with endometriosis. METHODS: Allele frequencies of SNPs were investigated in 1685 Caucasian women consisting of 947 women with endometriosis and 738 controls. Peripheral blood samples were retrieved, DNA extracted and allelic frequencies of SNPs in two tumor-suppressor genes (CHD5 and ARID1A) were analyzed using TaqMan Open Array technique. RESULTS: Associations were observed for 3 SNPs in the CHD5 gene: rs1883603 (OR 1.31, 95% CI 1.00-1.71), rs9434741 (OR 1.41, 95% CI 1.16-1.71) and rs17436816 (OR 1.24, 95% CI 1.02-1.50). After correction for multiple comparisons, rs9434741 (CHD5) remained significantly associated with endometriosis (p<0.01). No associations were detected for ARID1A. CONCLUSIONS: In this Caucasian population, endometriosis seems to be associated with the tumor-suppressor gene CHD5. Our findings support recent data, suggesting that the 1p36 region plays an important role in endometrios. To validate these data, replication in an independent population is warranted.

Proteomics analysis of plasma for early diagnosis of endometriosis.

OBJECTIVE: To test the hypothesis that differential surface-enhanced laser desorption/ionization time-of-flight mass spectrometry protein or peptide expression in plasma can be used in infertile women with or without pelvic pain to predict the presence of laparoscopically and histologically confirmed endometriosis, especially in the subpopulation with a normal preoperative gynecologic ultrasound examination. METHODS: Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry analysis was performed on 254 plasma samples obtained from 89 women without endometriosis and 165 women with endometriosis (histologically confirmed) undergoing laparoscopies for infertility with or without pelvic pain. Data were analyzed using least squares support vector machines and were divided randomly (100 times) into a training data set (70%) and a test data set (30%). RESULTS: Minimal-to-mild endometriosis was best predicted (sensitivity 75%, 95% confidence interval [CI] 63-89; specificity 86%, 95% CI 71-94; positive predictive value 83.6%, negative predictive value 78.3%) using a model based on five peptide and protein peaks (range 4.898-14.698 m/z) in menstrual phase samples. Moderate-to-severe endometriosis was best predicted (sensitivity 98%, 95% CI 84-100; specificity 81%, 95% CI 67-92; positive predictive value 74.4%, negative predictive value 98.6%) using a model based on five other peptide and protein peaks (range 2.189-7.457 m/z) in luteal phase samples. The peak with the highest intensity (2.189 m/z) was identified as a fibrinogen ß-chain peptide. Ultrasonography-negative endometriosis was best predicted (sensitivity 88%, 95% CI 73-100; specificity 84%, 95% CI 71-96) using a model based on five peptide peaks (range 2.058-42.065 m/z) in menstrual phase samples. CONCLUSION: A noninvasive test using proteomic analysis of plasma samples obtained during the menstrual phase enabled the diagnosis of endometriosis undetectable by ultrasonography with high sensitivity and specificity. LEVEL OF EVIDENCE: II.

A high sensitivity assay is more accurate than a classical assay for the measurement of plasma CRP levels in endometriosis.

BACKGROUND: Endometriosis is associated with chronic subclinical inflammation. C-reactive protein (CRP), a marker of inflammation, could serve as a biomarker of endometriosis. We tested the hypothesis that a high sensitivity CRP assay (hsCRP) is more accurate than a classical CRP assay in the detection of subclinical inflammation in plasma of women with endometriosis. METHODS: CRP levels were measured by hsCRP and classical CRP assays in plasma of 204 women with endometriosis and 91 women without endometriosis. Both assays were compared with respect to their value for the diagnosis of endometriosis. RESULTS: The number of plasma samples with detectable CRP was significantly higher (100%) using the hsCRP assay when compared to the classical CRP assay (42.7%) (p < 0.0001). Significantly increased CRP plasma levels were found in women with endometriosis when compared with controls when the hsCRP assay was used in samples obtained during the luteal phase (p = 0.008). The highest discriminative ability for the diagnosis of endometriosis was also obtained using the hsCRP assay during the luteal phase, especially for moderate -severe endometriosis. At a cut-off level of hsCRP > 0.71 mg/L, moderate-severe stages were diagnosed with 80.7% sensitivity and 63.9% specificity during the luteal phase. Using a similar cut-off value for CRP analyzed by the classical method, moderate-severe endometriosis was diagnosed with lower sensitivity (67.7%, p = 0.06) and comparable specificity (63.9%). CONCLUSIONS: The hsCRP assay was superior to the classical CRP assay for the detection of low CRP levels and for revealing subclinical inflammation in plasma of women with endometriosis.

How can macroscopically normal peritoneum contribute to the pathogenesis of endometriosis?

This study indicates that the immunobiology of macroscopically normal peritoneum is relevant to understand the pathogenesis of endometriosis. Peritoneal interleukin 6, interleukin 12, and ferritin were differentially expressed in women with and without endometriosis.

Evaluation of endometrial biomarkers for semi-invasive diagnosis of endometriosis.

OBJECTIVE: To test the hypothesis that specific proteins and peptides are expressed differentially in eutopic endometrium of women with and without endometriosis and at specific stages of the disease (minimal, mild, moderate, or severe) during the secretory phase. DESIGN: Patients with endometriosis were compared with controls. SETTING: University hospital. PATIENT(S): A total of 29 patients during the secretory phase were selected for this study on the basis of cycle phase and presence or absence of endometriosis. INTERVENTION(S): Endometriosis was confirmed laparoscopically and histologically in 19 patients with endometriosis of revised American Society for Reproductive Medicine stages (9 minimal-mild and 10 moderate-severe), and the presence of a normal pelvis was documented by laparoscopy in 10 controls. MAIN OUTCOME MEASURE(S): Protein expression of endometrium was evaluated with use of surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. The differential expression of protein mass peaks was analyzed with use of support vector machine algorithms and logistic regression models. RESULT(S): Data preprocessing resulted in differential expression of 73, 30, and 131 mass peaks between controls and patients with endometriosis (all stages), with minimal-mild endometriosis, and with moderate-severe endometriosis, respectively. Endometriosis was diagnosed with high sensitivity (89.5%) and specificity (90%) with use of five down-regulated mass peaks (1.949 kDa, 5.183 kDa, 8.650 kDa, 8.659 kDa, and 13.910 kDa) obtained after support vector machine ranking and logistic regression classification. With use of a similar analysis, minimal-mild endometriosis was diagnosed with four mass peaks (two up-regulated: 35.956 kDa and 90.675 kDa and two down-regulated: 1.924 kDa and 2.504 kDa) with maximal sensitivity (100%) and specificity (100%). The 90.675-kDa and 35.956-kDa mass peaks were identified as T-plastin and annexin V, respectively. CONCLUSION(S): Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry analysis of secretory phase endometrium combined with bioinformatics puts forward a prospective panel of potential biomarkers with sensitivity of 100% and specificity of 100% for the diagnosis of minimal to mild endometriosis.

Endometriosis and autoimmune disease: association of susceptibility to moderate/severe endometriosis with CCL21 and HLA-DRB1.

This study investigates the association of rheumatoid arthritis-associated single nucleotide polymorphisms in endometriosis. We found an association of CCL21 (rs2812378) and HLA-DRB1 (rs660895) with moderate to severe endometriosis.

Olfactomedin-4 regulation by estrogen in the human endometrium requires epidermal growth factor signaling.

Olfactomedin-4 (OLFM-4) is an extracellular matrix protein that is highly expressed in human endometrium. We have examined the regulation and function of OLFM-4 in normal endometrium and in cases of endometriosis and endometrial cancer. OLFM-4 expression levels are highest in proliferative-phase endometrium, and 17ß-estradiol up-regulates OLFM-4 mRNA in endometrial explant cultures. Using the luciferase reporter under control of the OLFM-4 promoter, it was shown that both 17ß-estradiol and OH-tamoxifen induce luciferase activity, and epidermal growth factor receptor-1 is required for this estrogenic response. In turn, EGF activates the OLFM-4 promoter, and estrogen receptor-α is needed for the complete EGF response. The cellular functions of OLFM-4 were examined by its expression in OLFM-4-negative HEK-293 cells, which resulted in decreased vimentin expression and cell adherence as well as increased apoptosis resistance. In cases of endometriosis and endometrial cancer, OLFM-4 expression correlated with the presence of epidermal growth factor receptor-1 and estrogen receptor-α (or estrogen signaling). An increase of OLFM-4 mRNA was observed in the endometrium of endometriosis patients. No change in OLFM-4 expression levels were observed in patients with endometrial cancer relative with controls. In conclusion, cross-talk between estrogen and EGF signaling regulates OLFM-4 expression. The role of OLFM-4 in endometrial tissue remodeling before the secretory phase and during the predisposition and early events in endometriosis can be postulated but requires additional investigation.

TRIzol treatment of secretory phase endometrium allows combined proteomic and mRNA microarray analysis of the same sample in women with and without endometriosis.

BACKGROUND: According to mRNA microarray, proteomics and other studies, biological abnormalities of eutopic endometrium (EM) are involved in the pathogenesis of endometriosis, but the relationship between mRNA and protein expression in EM is not clear. We tested for the first time the hypothesis that EM TRIzol extraction allows proteomic Surface Enhanced Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry (SELDI-TOF MS) analysis and that these proteomic data can be related to mRNA (microarray) data obtained from the same EM sample from women with and without endometriosis. METHODS: Proteomic analysis was performed using SELDI-TOF-MS of TRIzol-extracted EM obtained during secretory phase from patients without endometriosis (n = 6), patients with minimal-mild (n = 5) and with moderate-severe endometriosis (n = 5), classified according to the system of the American Society of Reproductive Medicine. Proteomic data were compared to mRNA microarray data obtained from the same EM samples. RESULTS: In our SELDI-TOF MS study 32 peaks were differentially expressed in endometrium of all women with endometriosis (stages I-IV) compared with all controls during the secretory phase. Comparison of proteomic results with those from microarray revealed no corresponding genes/proteins. CONCLUSION: TRIzol treatment of secretory phase EM allows combined proteomic and mRNA microarray analysis of the same sample, but comparison between proteomic and microarray data was not evident, probably due to post-translational modifications.

Increased exposure to dioxin-like compounds is associated with endometriosis in a case-control study in women.

Although endometriosis is thought to be an environmental disorder initiated by dioxin exposure, this association is controversial. This study was performed to test the hypothesis that endometriosis occurs more often in women exposed to higher concentrations of dioxin-like compounds (DLC) than in those women exposed to lower concentrations. Plasma samples collected prior to laparoscopic surgery from 96 women with endometriosis and 106 control patients with a normal pelvis were measured for DLC concentrations using the dioxin-responsive chemical-activated luciferase expression bioassay. The results showed that concentration (mean+/-SD) of DLC was marginally higher in patients with endometriosis (22.3+/-9.3pg CALUX-TEQ/g lipid) than in controls (20.5+/-10.8pg). After categorization of patients in a group with 'low' plasma concentrations (<25th centile) and a group with 'high' plasma concentrations (>75th centile) of DLC, the age-adjusted odds ratio to have endometriosis was 2.44 (95% CI 1.04-5.70; P=0.04) for women with high concentrations of DLC and it increased to 3.01 (95% CI 1.06-9.04; P=0.03) when only women with moderate severe endometriosis were considered. In conclusion, women exposed to higher plasma concentrations of DLC were at higher risk of having endometriosis than women exposed to lower concentrations of DLC within normal environmental concentrations.

Reassessing the evidence for the link between dioxin and endometriosis: from molecular biology to clinical epidemiology.

A 1993 study reporting the link between exposure to dioxin and the risk of developing endometriosis in rhesus monkeys prompted many investigators to look suspiciously at dioxin. Since 1993, many in vitro, animal and epidemiological studies have been published, but the link between dioxin exposure and endometriosis is still unclear. The aim of our review is to present a summary of the biological effects of dioxin and its aryl hydrocarbon receptor, and to reassess the evidence presented in published, in vitro, preclinical and epidemiological studies regarding the association between dioxins and endometriosis. Although in vitro and animal studies provide results in support for a role of dioxins in the pathogenesis of endometriosis, caution should be exercised since these findings are mostly context dependent and since negative findings from these studies are rarely published. On the basis of our review of original epidemiological studies, no significant evidence can be found to support a link between dioxins and endometriosis in women. This observation can be explained by positive publication bias and by significant methodological problems associated with these studies, or by the absence of such a link. In conclusion, it seems that there is insufficient evidence at this moment in support of the hypothesis that dioxin exposure may lead to increased risk of developing endometriosis in women.

Plasma C3a-des-Arg levels in women with and without endometriosis.

PROBLEM: The lack of a reliable method for early non-invasive detection of endometriosis often results in delayed diagnosis. The aim of this study was to test the hypothesis that the plasma concentration of complement factor C3a (anaphylatoxin) can be used as a non-invasive test in the diagnosis of endometriosis. METHOD OF STUDY: The C3a concentration was analyzed using ELISA in 160 patients with (n = 109) or without (n = 51) endometriosis during menstruation (n = 49), follicular phase (n = 55), and luteal (n = 56) phase. RESULTS: Plasma C3a concentration was comparable between patients with [102 (27-2213) ng/mL] and without [105 (32-2340) ng/mL] (P = 0.84) endometriosis, also when assessed separately during menstruation, follicular phase, and luteal phase. CONCLUSION: We found no difference in C3a levels between women with and without endometriosis and did not confirm our hypothesis that plasma C3a levels can be used as diagnostic test for endometriosis.

Role of cytokines in the endometrial-peritoneal cross-talk and development of endometriosis.

A clear picture of the dynamic relationship between the endometrium and peritoneum is emerging as both tissues may participate in the spontaneous development of endometriosis. Various adhesion molecules, pro-inflammatory cytokines and chemoattractants cytokines have emerged as central coordinators of endometrial-peritoneal interactions. The peritoneal microenvironment which consists of the peritoneal fluid, normal peritoneum and peritoneal endometriotic lesions may play an active role in the pathogenesis of endometriosis, by harbouring most inflammatory responses that are triggered by the presence of endometrial cells, leading to recruitment of activated macrophages and leukocytes locally. Menstrual endometrium has the ability to bond and invade the peritoneal tissue. In baboons intrapelvic injection of menstrual endometrium permits the study of early endometrial-peritoneal interaction in an in vivo culture microenvironment and can lead to important insight in the early development of endometriotic lesions. In this review, we discuss the roles of the endometrial-peritoneal interactions, not only in disease development but also in the broader process of aetiopathogenesis.

Increased production of 17beta-estradiol in endometriosis lesions is the result of impaired metabolism.

CONTEXT: substantial evidence suggests that the expression of steroid metabolizing enzymes in endometriosis is altered, turning the ectopic endometrium into a source of 17beta-estradiol. However, whether these differences result in a net increase in local 17beta-estradiol production/activity has not been shown. SUBJECTS AND METHODS: The activities of the most important steroidogenic enzymes synthesizing and inactivating 17beta-estradiol were determined by HPLC in matched eutopic and ectopic tissue from patients with endometriosis (n = 14) and in endometrium from controls (n = 20). RESULTS: Aromatase activity is negligible in the ectopic endometrium, whereas the activity of estrogen sulfatase is high though not different between ectopic, eutopic and control endometrium. The activity of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) converting estrone into 17beta-estradiol is higher in the ectopic compared to the eutopic endometrium in patients. The activity of 17beta-HSDs converting 17beta-estradiol back to estrone is significantly lower in the ectopic compared to the eutopic endometrium of both patients and controls. To evaluate the net metabolic capacity of tissues to synthesize 17beta-estradiol, we calculated the activity ratio between 17beta-HSDs synthesizing versus 17beta-HSDs inactivating 17beta-estradiol. This ratio is significantly higher in the ectopic compared to the eutopic endometrium of patients and controls, indicating a high synthesis of 17beta-estradiol in the ectopic locations. This is further supported by the elevated mRNA levels of the estrogen-responsive gene TFF1 in all ectopic compared to eutopic endometria. CONCLUSION: Endometriotic lesions have higher production of 17beta-estradiol than the eutopic endometrium of patients and controls. This is mostly the result of impaired metabolism.

Endometrial and peritoneal expression of aromatase, cytokines, and adhesion factors in women with endometriosis.

OBJECTIVE: To examine messenger (m) RNA expression of aromatase, cytokines, and adhesion factors in women with and without endometriosis. DESIGN: Patients with endometriosis were compared with control patients. SETTING: University Hospital Gasthuisberg, Leuven, Belgium. PATIENT(S): A total of 35 patients who had laparoscopic surgery during the luteal phase (n = 20) or the menstrual phase (n = 15) were selected for this study based on cycle phase and presence/absence of endometriosis. INTERVENTION(S): Tissues of endometrium and macroscopically normal peritoneum were collected during hysteroscopy and laparoscopic surgery, respectively, from 24 women with revised American Society for Reproductive Medicine stage (rASRM) stages I-II (n = 12) and III-IV (n = 12) endometriosis and 11 control patients with normal pelvic. Tissue samples were selected from a tissue bank, based on the phase of the cycle (menstrual or luteal) and the presence/absence of endometriosis. MAIN OUTCOME MEASURE(S): The mRNA levels of aromatase, vimentin, vascular cell adhesion molecule 1 (VCAM-1), alpha(V) and beta(3) integrins, interleukin (IL)-1 beta, regulated on activation normal T-cell expressed and secreted (RANTES), and monocyte chemotactic protein 1 (MCP-1) were evaluated using real-time reverse transcriptase polymerase chain reaction. RESULT(S): During menstrual phase, increased endometrial mRNA levels of alpha(V) integrin, combined alpha(V)beta(3) integrins, and increased peritoneal IL-1 beta mRNA levels--but decreased peritoneal MCP-1 mRNA levels--were observed in women with endometriosis compared with control subjects. During luteal phase, endometrial mRNA levels of IL-1 beta and RANTES were increased in women with endometriosis compared with control subjects. Endometrial aromatase mRNA expression was higher in women with endometriosis than in control subjects in combined phases. Women with endometriosis had increased peritoneal mRNA expression of RANTES and VCAM-1 during menstrual compared with luteal phase. CONCLUSION(S): Aberrant mRNA expression of aromatase, cytokines, and adhesion factors in endometrium and peritoneum suggests that both tissues are involved in the pathogenesis of endometriosis.

Effect of recombinant human TNF-binding protein-1 and GnRH antagonist on mRNA expression of inflammatory cytokines and adhesion and growth factors in endometrium and endometriosis tissues in baboons.

OBJECTIVE: To evaluate the mechanism of action of recombinant human tumor necrosis factor (TNF)-binding protein-1 by assessing differential expression of messenger RNA (mRNA) for cytokines, matrix metalloproteinases, and growth and adhesion factors in baboons. DESIGN: Analysis of gene expression in a prospective randomized study. SETTING: University Fertility Center. ANIMAL(S): In the in vivo study, 14 baboons were randomly and subcutaneously (SC) treated with either phosphate-buffered saline (PBS), GnRH antagonist, or recombinant human TNF-binding protein-1 at the time of induction. In the ex vivo study, 4 baboons were treated by menstrual endometrium that had been incubated randomly with either PBS or recombinant human TNF-binding protein-1 before intrapelvic injection. INTERVENTION(S): In the in vivo study, analysis of 11 endometrial and 10 endometriosis biopsies included either PBS (n = 5), GnRH antagonist (n = 8), or recombinant human TNF-binding protein-1 (n = 8). In the ex vivo study, 2 endometrial and 4 endometriosis biopsies were analyzed from 4 baboons. MAIN OUTCOME MEASURE(S): The mRNA expression of TNF-alpha, IL-8, IL-6, transforming growth factor-beta (TGF-beta), vascular endothelial growth factor, intercellular adhesion molecule-1, matrix metalloproteinase-1, and regulated on activation, normal T-cell expressed and secreted were investigated using real-time reverse transcriptase-polymer chain reaction (PCR). RESULT(S): TGF-beta mRNA expression was decreased in endometriotic lesions from baboons treated with recombinant human TNF-binding protein-1 when compared with the placebo group. CONCLUSION(S): Except TGF-beta, mRNA expression of inflammatory cytokines and adhesion/growth factors is not affected in endometrial and endometriosis biopsies from baboons after induction of endometriosis combined with either systemic injection of recombinant human TNF-binding or GnRH antagonist or ex vivo treatment with recombinant human TNF-binding protein-1. Further studies are needed to elucidate the mode of action on how inhibition of TNF-alpha activity prevents the development of endometriosis.

Selective estrogen-receptor modulators and aromatase inhibitors: promising new medical therapies for endometriosis?

Endometriosis is an estrogen-dependent disease and estrogen-related pathways are imbalanced in women with endometriosis. One of the key enzymes in estrogen synthesis is aromatase. Inhibiting this pathway at several points is a promising idea for the treatment of endometriosis. The third generation of aromatase inhibitors is becoming more potent in efficacy, with fewer side effects than previous generations, but cotreatment with other hormones is needed to inhibit ovarian stimulation. Other components that promote estrogen synthesis such as COX-2 can also be potentially targeted. Selective estrogen-receptor modulators could also be interesting in view of their tissue-specific effect. However, all these new drugs are still in an early phase of development. At present, it is too early to conclude that aromatase inhibitors, COX-2 inhibitors or selective estrogen-receptor modulators really present any added value compared with the existing drugs that can be used to achieve hormonal suppression in the medical treatment of endometriosis.