Two Unsuccessful Clinical Trials on Endometriosis and a Few Lessons Learned

6-Shogaol reduces progression of experimental endometriosis in vivo and in vitro via regulation of VGEF and inhibition of COX-2 and PGE2-mediated inflammatory responses

Endometriosis (EM) is one of the most common gynaecological disorder affecting women in their reproductive age. Mechanisms involved in the pathogenesis of EM remains poorly understood, however inflammatory responses have been reported to be significantly involved. The efficacy of 6-shogaol on proliferation of endometriotic lesions and inflammatory pathways in experimentally-induced EM model was explored in this study. EM was stimulated in Sprague-Dawley rats by implantation of autologous endometrium onto the peritoneum abdominal wall. Separate groups were treated with 6-shogaol (50, 100 or 150 mg/kg b.wt/day) via oral gavage for one month period. Gestrinone (GTN) group received GTN (0.5 mg/kg/day) as positive control. Five weeks after implantation, the spherical volume of ecto-uterine tissues was determined. Treatment with 6-shogaol significantly reduced the implant size. Histological analysis reported atrophy and regression of the lesions. 6-shogaol administration effectively down-regulated NF-κB signaling, VEGF and VEGFR-2 (Flk-1) expression in the endometriotic lesions. Excess production of IL-1β and IL-6 (pro-inflammatory cytokines), PGE2 and nitric oxide (NO) were reduced. Overall, the results of the study reveal the efficacy of 6-shogaol against endometriosis via effectively suppressing proliferation of the lesions and modulating angiogenesis and COX-2/NF-κB-mediated inflammatory cascades.

Investigational drugs for the treatment of endometriosis, an update on recent developments

INTRODUCTION

Endometriosis is a hormone-dependent benign chronic disease that requires a chronic medical therapy. Although currently available drugs are efficacious in treating endometriosis-related pain, some women experience partial or no improvement. Moreover, the recurrence of symptoms is expected after discontinuation of the therapies. Currently, new drugs are under intense clinical investigation for the treatment of endometriosis.

AREAS COVERED

This review aims to offer the reader a complete and updated overview on new investigational drugs and early molecular targets for the treatment of endometriosis. The authors describe the pre-clinical and clinical development of these agents.

EXPERT OPINION

Among the drugs under investigation, late clinical trials on gonadotropin-releasing hormone antagonists (GnRH-ant) showed the most promising results for the treatment of endometriosis. Aromatase inhibitors (AIs) are efficacious in treating endometriosis related pain symptoms but they cause significant adverse effects that limit their long-term use. New targets have been identified to produce drugs for the treatment of endometriosis, but the majority of these new compounds have only been investigated in laboratory studies or early clinical trials. Thus, further clinical research is required in order to elucidate their efficacy and safety in human.

The Usefulness of CD34, PCNA Immunoreactivity, and Histopathological Findings for Prediction of Pain Persistence After the Removal of Endometrioma

Endometriosis is an estrogen-dependent inflammatory disease that causes infertility and chronic pelvic pain. Ovarian endometrioma is the most common form of endometriosis, and conservative surgery is the main preferred therapeutic approach for endometrioma-associated symptoms. The aim of this study was to investigate the persistence of cyclic and noncyclic pelvic pain (NCPP) after endometrioma excision and their relationship to clinical and histopathological findings. In this prospective observational study, 41 symptomatic patients were evaluated for the presence of pain symptoms 3 to 6 months after endometrioma excision. Tissue specimens of endometrioma were collected during the operation and embedded in paraffin. The persistence of pain was 41.4%. Surgical excision of endometrioma significantly decreased NCPP and dysmenorrhea, but not dyspareunia ( P < .0001, P = .0001, and P = .25, respectively). Histopathological changes, including depth of endometriosis penetration into the cyst wall, the presence of macrophage infiltration, and vascularity of endometrioma cyst walls were significantly higher in patients with pain persistence than in patients without pain persistence ( P = .0034, P = .0042, and P = .0007, respectively). Moreover, proliferating cell nuclear antigen (PCNA) and CD34 immunoreactivity in both glandular and stromal cells and vascular endothelium were significantly higher in patients with pain persistence ( P = .0079 and P = .0025, respectively). Additionally, these histopathological changes and PCNA and CD34 immunoreactivity were significantly correlated with the persistence of NCPP and dysmenorrhea. The discovered differences in patients with endometrioma with or without pain persistence may indicate a possible relationship between endometrioma-associated pain and histopathological variability of endometrioma.

Euterpe oleracea Extract (Açaí) Is a Promising Novel Pharmacological Therapeutic Treatment for Experimental Endometriosis

This study investigated the therapeutic potential of Euterpe oleracea extract (açaí) on the growth and survival of endometriotic lesions using an experimental model. Twenty female Sprague-Dawley rats were randomized into two groups after the implantation and establishment of autologous endometrium onto the peritoneum abdominal wall and treated with 200 mg/kg hydroalcoholic solution extract from açaí stone or vehicle via gastric tube for 30 consecutive days. Body weight, lesion surface areas, histological and immunohistochemistry analyses of vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2), metalloproteinase-9 (MMP-9), cyclooxygenase-2 (COX-2) and F4-80 were performed. Levels of VEGF, VEGFR-2, MMP-9 and COX-2 mRNA were measured. Flow cytometry of F4-80 was performed, and ELISA immunoassays measured prostaglandin E₂ (PGE₂), VEGF and nitric oxide (NO) and concentrations. Macrophage cell line J774.G8 was treated with 10, 20, and 40 μg/mL of açaí for 24, 48 and 72 h, and cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Açaí treatment significantly decreased the implant size, and histological examination indicated atrophy and regression. A reduction in immunostaining and mRNA expression of VEGF, MMP-9 and COX-2 was observed, and F4-80 was lower in the treated group than the control group. The treated group also exhibited lower concentrations of PGE₂, VEGF and NO compared to the control group. Macrophages cells treated with 20 and 40 μg/ml of açaí reduced cell viability in about 50% after 24, 48 and 72 h. Our results suggest that açaí effectively suppressed the establishment and growth of endometriotic lesions, and this agent is a promising novel pharmacological therapeutic treatment for endometriosis.

Selective modulation of the prostaglandin F2α pathway markedly impacts on endometriosis progression in a xenograft mouse model

STUDY HYPOTHESIS

Selective activation or blockade of the prostaglandin (PG) F2α receptor (FP receptor) affects ectopic endometrial tissue growth and endometriosis development.

STUDY FINDING

FP receptor antagonists might represent a promising approach for the treatment of peritoneal endometriosis.

WHAT IS KNOW ALREADY

Eutopic and ectopic endometrium from women with endometriosis exhibit higher expression of key enzymes involved in the PGF2α biosynthetic pathway. It has also been shown that the PGF2α-FP receptor interaction induces angiogenesis in human endometrial adenocarcinoma.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

For this study, a mouse model of endometriosis was developed by inoculating human endometrial biopsies into the peritoneal cavity of nude mouse (n = 15). Mice were treated with AL8810 (FP receptor antagonist), Fluprostenol (FP receptor agonist) or PBS. Endometriosis-like lesions were collected and analysed for set of markers for angiogenesis, tissue remodelling, apoptosis, cell proliferation and capillary formation using qPCR and immunohistochemistry.

MAIN RESULTS AND THE ROLE OF CHANCE

We found that selective inhibition of the FP receptor with a specific antagonist, AL8810, led to a significant decline in the number (P < 0.01) and size of endometriosis-like lesions (P < 0.001), down-regulated the expression of key mediators of tissue remodelling (MMP9, P < 0.05) and angiogenesis (VEGF, P < 0.01) and up-regulated the pro-apoptotic factor (Bax, P < 0.01) as compared with controls. Immunohistochemical analyses further showed a marked decrease in cell proliferation and capillary formation in endometrial implants from AL8810-treated mice, as determined by proliferating cell nuclear antigen (PCNA) and von Willebrand factor (vWF) immunostaining, respectively. Moreover, Fluprostenol, a selective FP receptor agonist, showed the opposite effects.

LIMITATIONS, REASONS FOR CAUTION

We carried out this study in nude mice, which have low levels of endogenous estrogens which may affect the lesion growth. Caution is required when interpreting these results to women.

WIDER IMPLICATIONS OF THE FINDINGS

This study extends the role of PG signalling in endometriosis pathogenesis and points towards the possible relevance of selective FP receptor antagonism as a targeted treatment for endometriosis.

LARGE SCALE DATA

Not Applicable.

STUDY FUNDING AND COMPETING INTERESTS

This work was supported by grant MOP-123259 to the late Dr Ali Akoum from the Canadian Institutes for Health Research. The authors have no conflict of interest.

Medical treatment for adenomyosis and/or adenomyoma

Uterine adenomyosis and/or adenomyoma is characterized by the presence of heterotopic endometrial glands and stroma within the myometrium, >2.5 mm in depth in the myometrium or more than one microscopic field at 10 times magnification from the endometrium-myometrium junction, and a variable degree of adjacent myometrial hyperplasia, causing globular and cystic enlargement of the myometrium, with some cysts filled with extravasated, hemolyzed red blood cells, and siderophages. Hysterectomy is a "gold standard" and definitive therapy for uterine adenomyosis, and many cases of adenomyosis have been diagnosed by pathological review retrospectively. As such, the diagnosis of adenomyosis is difficult, and this subsequently results in difficulty in the management of these patients, especially those who are symptomatic but have a strong desire to preserve their uterus. In our previous review, we found that the use of uterine-sparing surgery in the management of uterine adenomyosis and/or adenomyoma is still controversial, although some data support its feasibility. Conservative treatment is still needed in the group of patients that requires preservation of fertility and improvement of quality of life. However, studies focusing on the topic of medical treatment for adenomyosis are rare. In this article, current knowledge regarding the use of medical therapy for uterine adenomyosis, partly based on the understanding of endometriosis, is reviewed.

Molecular and preclinical basis to inhibit PGE2 receptors EP2 and EP4 as a novel nonsteroidal therapy for endometriosis

Endometriosis is a debilitating, estrogen-dependent, progesterone-resistant, inflammatory gynecological disease of reproductive age women. Two major clinical symptoms of endometriosis are chronic intolerable pelvic pain and subfertility or infertility, which profoundly affect the quality of life in women. Current hormonal therapies to induce a hypoestrogenic state are unsuccessful because of undesirable side effects, reproductive health concerns, and failure to prevent recurrence of disease. There is a fundamental need to identify nonestrogen or nonsteroidal targets for the treatment of endometriosis. Peritoneal fluid concentrations of prostaglandin E2 (PGE2) are higher in women with endometriosis, and this increased PGE2 plays important role in survival and growth of endometriosis lesions. The objective of the present study was to determine the effects of pharmacological inhibition of PGE2 receptors, EP2 and EP4, on molecular and cellular aspects of the pathogenesis of endometriosis and associated clinical symptoms. Using human fluorescent endometriotic cell lines and chimeric mouse model as preclinical testing platform, our results, to our knowledge for the first time, indicate that selective inhibition of EP2/EP4: (i) decreases growth and survival of endometriosis lesions; (ii) decreases angiogenesis and innervation of endometriosis lesions; (iii) suppresses proinflammatory state of dorsal root ganglia neurons to decrease pelvic pain; (iv) decreases proinflammatory, estrogen-dominant, and progesterone-resistant molecular environment of the endometrium and endometriosis lesions; and (v) restores endometrial functional receptivity through multiple mechanisms. Our novel findings provide a molecular and preclinical basis to formulate long-term nonestrogen or nonsteroidal therapy for endometriosis.

Selective inhibition of prostaglandin E2 receptors EP2 and EP4 modulates DNA methylation and histone modification machinery proteins in human endometriotic cells

Endometriosis is an inflammatory gynecological disease of reproductive-age women. The prevalence of endometriosis is 5-10% in reproductive-age women. Modern medical treatments are directed to inhibit the action of estrogen in endometriotic cells. However, hormonal therapies targeting estrogen can be prescribed only for a short time because of their undesirable side effects. Recent studies from our laboratory, using human endometriotic epithelial cell line 12Z and stromal cell line 22B derived from red lesion, discovered that selective inhibition of prostaglandin E2 (PGE2) receptors EP2 and EP4 inhibits adhesion, invasion, growth, and survival of 12Z and 22B cells by modulating integrins, MMPs and TIMPs, cell cycle, survival, and intrinsic apoptotic pathways, suggesting multiple epigenetic mechanisms. The novel findings of the present study indicate that selective pharmacological inhibition of EP2 and EP4: (i) decreases expression of DNMT3a, DNMT3b, H3K9me3, H3K27me3, SUV39H1, HP1a, H3K27, EZH2, JMJD2a, HDAC1, HDAC3, MeCP2, CoREST and Sin3A; (ii) increases expression of H3K4me3, H3H9ac, H3K27ac; and (iii) does not modulate the expression of DNMT1, hSET1, LSD1, MBD1, p300, HDAC2, and JMJD3 epigenetic machinery proteins in an epithelial and stromal cell specific manner. In this study, we report for the first time that inhibition of PGE2-EP2/EP4 signaling modulates DNA methylation, H3 histone methylation and acetylation, and epigenetic memory machinery proteins in human endometriotic epithelial cells and stromal cells. Thus, targeting EP2 and EP4 receptors may emerge as long-term nonsteroidal therapy for treatment of active endometriotic lesions in women.

Role of nociceptor estrogen receptor GPR30 in a rat model of endometriosis pain

Endometriosis, the most common cause of chronic pelvic pain, is an estrogen-dependent disease in which classic estrogen receptors (ERα, ERβ) play an important role. Although recent evidence suggests that the novel G protein-coupled estrogen receptor (GPR30) also plays a key role in the progression of endometriosis, whether it is also involved in endometriosis pain is still unknown. Here we tested the hypothesis that GPR30 expressed by nociceptors contributes to endometriosis pain. Intramuscular injection of the GPR30 agonists raloxifene or 17β-estradiol produced a fast-onset, persistent, mechanical hyperalgesia at the site of the injection. Intrathecal antisense (AS) oligodeoxynucleotides (ODN), but not mismatch (MM) ODN, targeting mRNA for GPR30 markedly inhibited its protein expression in nociceptors and attenuated the mechanical hyperalgesia induced by local raloxifene or 17β-estradiol. Pretreatment with the GPR30 antagonist G-36 also inhibited the hyperalgesia induced by raloxifene or 17β-estradiol in naive control rats. Surgical implant of autologous uterine tissue onto the gastrocnemius muscle, which induces endometriosis-like lesions, produced local mechanical hyperalgesia. Intrathecal AS, but not MM, ODN targeting GPR30 mRNA reversibly inhibited the mechanical hyperalgesia at the site of endometriotic lesions. Finally, intralesional injection of the GPR30 antagonist G-36 also inhibited the mechanical hyperalgesia at the site of ectopic uterine tissue. We conclude that local GPR30 agonists produce persistent mechanical hyperalgesia in naive female rats, whereas local GPR30 antagonists inhibit mechanical hyperalgesia in a model of endometriosis pain. Thus, GPR30 expressed by nociceptors innervating ectopic uterine lesions might play a major role in endometriosis pain.

PPARγ activation inhibits growth and survival of human endometriotic cells by suppressing estrogen biosynthesis and PGE2 signaling

Endometriosis is a chronic inflammatory disease of reproductive age women leading to chronic pelvic pain and infertility. Current antiestrogen therapies are temporizing measures, and endometriosis often recurs. Potential nonestrogenic or nonsteroidal targets are needed for treating endometriosis. Peroxisome proliferator-activated receptor (PPAR)γ, a nuclear receptor, is activated by thiazolidinediones (TZDs). In experimental endometriosis, TZDs inhibit growth of endometriosis. Clinical data suggest potential use of TZDs for treating pain and fertility concurrently in endometriosis patients. Study objectives were to 1) determine the effects of PPARγ action on growth and survival of human endometriotic epithelial and stromal cells and 2) identify the underlying molecular links between PPARγ activation and cell cycle regulation, apoptosis, estrogen biosynthesis, and prostaglandin E2 biosynthesis and signaling in human endometriotic epithelial and stromal cells. Results indicate that activation of PPARγ by TZD ciglitazone 1) inhibits growth of endometriotic epithelial cells 12Z up to 35% and growth of endometriotic stromal cells 22B up to 70% through altered cell cycle regulation and intrinsic apoptosis, 2) decreases expression of PGE2 receptors (EP)2 and EP4 mRNAs in 12Z and 22B cells, and 3) inhibits expression and function of P450 aromatase mRNA and protein and estrone production in 12Z and 22B cells through EP2 and EP4 in a stromal-epithelial cell-specific manner. Collectively, these results indicate that PGE2 receptors EP2 and EP4 mediate actions of PPARγ by incorporating multiple cell signaling pathways. Activation of PPARγ combined with inhibition of EP2 and EP4 may emerge as novel nonsteroidal therapeutic targets for endometriosis-associated pain and infertility, if clinically proven safe and efficacious.

An overview of the current status of clinical trials on endometriosis: issues and concerns

OBJECTIVE

To examine and compare differences, if any, between industry- and nonindustry-sponsored clinical trials on endometriosis and to evaluate the effect of prior published positive preclinical results, or lack thereof, on trial status.

DESIGN

Cross-sectional study of clinical trials on endometriosis that evaluate drugs/biologicals registered at ClinicalTrials.gov as of July 3, 2013.

SETTING

University-affiliated hospital.

PATIENT(S)

None.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Trial status, size, phase, and duration; use of comparator groups; drug classes, number of arms, targeting conditions; and presence or absence of prior positive preclinical results before the launch of the trial.

RESULT(S)

Eighty trials were identified. The trials sponsored by industry and non-industry have distinct features, differing in trial status, phase, comparator, drug classes, number of arms, trial size, and duration. The phase II/III trials are predominantly industry supported, but these trials frequently use placebo as the comparator. Trials launched without prior published preclinical results do not seem to fare well, although the presence of such studies is no guarantee for success.

CONCLUSION(S)

Questions as to whether the drug on trial is truly superior to the best available drug or of its cost-benefit profile are overlooked in most cases. There seems to be a deluge of "me-too" drugs with equivocal superiority over existing drugs and cost-benefit profiles. Because clinical trials are time-consuming, no blockbuster drug for endometriosis seems to be on the horizon yet.

New treatment strategies and emerging drugs in endometriosis

Introduction: Endometriosis, histologically defined as the presence of endometrium-like tissue - glands and stroma - that develops outside of the uterine cavity, is still an enigmatic disease responsible for pelvic pain and infertility. The current treatments of endometriosis are surgery and hormonal therapies that act by suppressing ovulation and/or directly on steroid receptors located in endometriotic lesions. Areas covered: New hormonal and non-hormonal therapies are being developed for the treatment of endometriosis-related pain. The authors review the state of advancement and the results of novel treatments studied in registered trials ( www.ClinicalTrials.gov ). Cellular signaling pathways activated in endometriotic cells, which constitute potential targets for future treatments, are also described. Expert opinion: Therapeutic research efforts should focus on identifying and testing substances capable of acting locally on the lesions themselves, without interfering with ovulation, in order to be efficacious on both pain symptoms and infertility.

Use of a murine endometriosis interna model for the characterization of compounds that effectively treat human endometriosis

Endometriosis is a chronic, estrogen-dependent disease characterized by the presence of ectopic endometrium either in the pelvic cavity (endometriosis externa) or within the uterus (endometriosis interna, adenomyosis). Key symptoms are pelvic pain, dysmenorrhea and infertility. Established rodent animal models used for drug research in endometriosis have certain limitations. Since rodents do not menstruate, they cannot develop endometriosis externa spontaneously, but they suffer from endometriosis interna. There is growing evidence that human endometriosis externa and interna represent two faces of the same disease. Both are estrogen-dependent and respond to similar treatment paradigms. Here, we addressed the question whether a murine endometriosis interna model may also be suitable for the characterization of drugs employed in human endometriosis. We examined the effects of danazol, Faslodex and cetrorelix in SHN mice that developed endometriosis interna after pituitary grafting. The GnRH antagonist cetrorelix and the estrogen receptor antagonist Faslodex, which negatively interfered with estrogen-mediated signaling, completely inhibited endometriosis interna, whereas danazol, an androgenic progestin, showed significant therapeutic activity in the majority of SHN mice. We conclude that this murine endometriosis interna model may be a valuable complement to established endometriosis externa models to support drug research in human endometriosis.

Comparison of the effects of raloxifene and anastrozole on experimental endometriosis

OBJECTIVE

To compare the efficacies of anastrozole and raloxifene on endometriosis.

STUDY DESIGN

A randomized, placebo-controlled, single-blind, experimental study was performed on 45 adult Wistar female rats in the Experimental Surgery Laboratory at Ondokuz Mayis University in Turkey. Endometrial tissues were implanted on the abdominal peritoneum in 45 rats. Six weeks later, the implant volumes were measured (volume-1) by performing a second laparotomy. Rats were randomized to one of three equal study groups. Saline solution (0.1 cc/rat/week, subcutaneously) was administered to group 1 (control group), anastrozole (0.004 mg/rat/day, orally) to group 2 (anastrozole group), and raloxifene (0.24 mg/rat/day, orally) to group 3 (raloxifene group) for 8 weeks. At the end of administration, a third laparotomy was performed to remeasure implant volumes (volume-2), and implants were totally excised for histopathologic examination. Volume-1 and volume-2 within the groups, as well as stromal and glandular tissues between the groups, were compared.

RESULT(S)

In the anastrozole and raloxifene groups, volume-2 values were significantly lower than those of volume-1. When compared to the control group, in both anastrozole and raloxifene groups, while glandular tissue scores were found significantly lower, stromal tissue scores were not different than that of the control group. There was no significant difference between both the GT and ST scores of the anastrozole and raloxifene groups.

CONCLUSION(S)

Anastrozole and raloxifene were seen to have caused equally the regression of the experimental endometriosis statistically significantly.

Selective inhibition of prostaglandin E2 receptors EP2 and EP4 induces apoptosis of human endometriotic cells through suppression of ERK1/2, AKT, NFkappaB, and beta-catenin pathways and activation of intrinsic apoptotic mechanisms

Endometriosis is a benign chronic gynecological disease of reproductive-age women characterized by the presence of functional endometrial tissues outside the uterine cavity. It is an estrogen-dependent disease. Current treatment modalities to inhibit biosynthesis and actions of estrogen compromise menstruation, pregnancy, and the reproductive health of women and fail to prevent reoccurrence of disease. There is a critical need to identify new specific signaling modules for non-estrogen-targeted therapies for endometriosis. In our previous study, we reported that selective inhibition of cyclooxygenase-2 prevented survival, migration, and invasion of human endometriotic epithelial and stromal cells, which was due to decreased prostaglandin E(2) (PGE(2)) production. In this study, we determined mechanisms through which PGE(2) promoted survival of human endometriotic cells. Results of the present study indicate that 1) PGE(2) promotes survival of human endometriotic cells through EP2 and EP4 receptors by activating ERK1/2, AKT, nuclear factor-kappaB, and beta-catenin signaling pathways; 2) selective inhibition of EP2 and EP4 suppresses these cell survival pathways and augments interactions between proapoptotic proteins (Bax and Bad) and antiapoptotic proteins (Bcl-2/Bcl-XL), facilitates the release of cytochrome c, and thus activates caspase-3/poly (ADP-ribose) polymerase-mediated intrinsic apoptotic pathways; and 3) these PGE(2) signaling components are more abundantly expressed in ectopic endometriosis tissues compared with eutopic endometrial tissues during the menstrual cycle in women. These novel findings may provide an important molecular framework for further evaluation of selective inhibition of EP2 and EP4 as potential therapy, including nonestrogen target, to expand the spectrum of currently available treatment options for endometriosis in women.

Recurrence of endometriosis and its control

BACKGROUND Although surgery is currently the treatment of choice for managing endometriosis, recurrence poses a formidable challenge. To delay or to eliminate the recurrence is presently an unmet medical need in the management of endometriosis. To this end, proposals to investigate patterns of recurrence, to develop biomarkers for recurrence and to carry out biomarker-based intervention have been made. METHODS Publications pertaining to the recurrence of endometriosis and its related yet unaddressed issues were identified through MEDLINE. The reported recurrence rates, risk factors for recurrence, the effects of post-operative medication and causes of recurrence were reviewed and synthesized. In addition, several poorly explored issues such as time hazard function and mechanisms of recurrence were reviewed. Approaches to the development of biomarkers for recurrence and future intervention are discussed. RESULTS The reported recurrence rate was high, estimated as 21.5% at 2 years and 40-50% at 5 years. Few risk factors for recurrence have been consistently identified, and the evidence on the efficacy of the post-operative use of medication was scanty. The investigation on the patterns of recurrence may provide us with new insight into the possible mechanisms of recurrence and its control. The attempt to identify biomarkers for recurrence has started only very recently. CONCLUSIONS Much research is needed to better understand the patterns of recurrence and risk factors, and to develop biomarkers. One top priority is to develop biomarkers for recurrence, which may provide much needed clues to the possible mechanisms underlying recurrence and would allow the identification of patients with high recurrence risk, and permit for targeted intervention.

A call for more transparency of registered clinical trials on endometriosis

In response to the pressing need for more efficacious and safer therapeutics for endometriosis, there have been numerous reports in the last decade of positive results from animal and in vitro studies of various compounds as potential therapeutics for endometriosis. A handful of these have undergone phase II/III clinical trials. Since the announcement of the International Committee of Medical Journal Editors that mandated registration as a prerequisite for publication, 57 endometriosis-related clinical trials have been registered at ClinicalTrials.gov, an Internet-based public depository for information on drug studies. Among them, 25 are listed as completed, and 2 as suspended. There are 15 completed phase II/III trials, which evaluated the efficacy of various promising compounds. Yet only three of the 15 trials (20%) have published their results. The remaining 12 (80%) studies so far have not published their findings. We argue that this apparent lack of transparency will actually not benefit the trial sponsors or the public, and will ultimately prove detrimental to research efforts attempting to develop more efficacious and safer therapeutics for endometriosis. Thus we call for more transparency of clinical trials on endometriosis.

Estrogen inhibits RANKL-stimulated osteoclastic differentiation of human monocytes through estrogen and RANKL-regulated interaction of estrogen receptor-alpha with BCAR1 and Traf6

The effects of estrogen on osteoclast survival and differentiation were studied using CD14-selected mononuclear osteoclast precursors from peripheral blood. Estradiol at approximately 1 nM reduced RANKL-dependent osteoclast differentiation by 40-50%. Osteoclast differentiation was suppressed 14 days after addition of RANKL even when estradiol was withdrawn after 18 h. In CD14+ cells apoptosis was rare and was not augmented by RANKL or by 17-beta-estradiol. Estrogen receptor-alpha (ERalpha) expression was strongly down-regulated by RANKL, whether or not estradiol was present. Mature human osteoclasts thus cannot respond to estrogen via ERalpha. However, ERalpha was present in CD14+ osteoclast progenitors, and a scaffolding protein, BCAR1, which binds ERalpha in the presence of estrogen, was abundant. Immunoprecipitation showed rapid (approximately 5 min) estrogen-dependent formation of ERalpha-BCAR1 complexes, which were increased by RANKL co-treatment. The RANKL-signaling intermediate Traf6, which regulates NF-kappaB activity, precipitated with this complex. Reduction of NF-kappaB nuclear localization occurred within 30 min of RANKL stimulation, and estradiol inhibited the phosphorylation of IkappaB in response to RANKL. Inhibition by estradiol was abolished by siRNA knockdown of BCAR1. We conclude that estrogen directly, but only partially, curtails human osteoclast formation. This effect requires BCAR1 and involves a non-genomic interaction with ERalpha.

Peroxisome proliferator-activated receptor-gamma and retinoid X receptor agonists synergistically suppress proliferation of immortalized endometrial stromal cells

OBJECTIVE

To examine whether trichostatin A (TSA), a histone deacetylase inhibitor (HDACI), can induce up-regulation of peroxisome proliferator-activating receptor gamma (PPAR gamma) and to see whether LG100268, a retinoid X receptor (RXR) ligand, can inhibit proliferation of endometriotic cells alone or in synergy with ciglitazone, a PPAR gamma agonist.

DESIGN

One endometrial stromal cell line and two endometriotic cell lines used as a model system: Western blot analysis to determine whether TSA can up-regulate PPAR gamma expression, and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) proliferation assay to see whether ciglitazone and LG100268 have any antiproliferative effects individually or jointly.

SETTING

Academic.

PATIENT(S)

None.

INTERVENTION(S)

Culture of immortalized endometrial and endometriotic cell lines with TSA, or ciglitazone or LG100268.

MAIN OUTCOME MEASURE(S)

PPAR gamma protein expression levels in cells treated with or without TSA, and number of viable cells treated with or without ciglitazone, LG100268, or both.

RESULT(S)

The TSA treatment resulted in up-regulation of PPAR gamma expression in all cell lines in a dose-dependent fashion. Both ciglitazone and LG100268 inhibited proliferation in a dose-dependent manner, and the antiproliferative effects appeared to be synergistic. In addition, endometriotic cells were more sensitive than endometrial stromal cells to LG100268 treatment.

CONCLUSION(S)

The up-regulation of PPAR gamma induced by TSA indicates that the action of HDACIs also includes the PPAR gamma signaling pathway, suggesting that the activation of PPAR gamma is a desirable way to contain endometriosis phenotypes. The higher sensitivity of endometriotic cells than their endometrial counterpart to LG100268 treatment suggests that the sensitivity differential could be exploited effectively to eradicate unwanted ectopic endometrial tissues while minimizing the collateral damage to the normal endometrial tissues.

Is There a Role for Acupuncture in Endometriosis Pain, Or ‘endometrialgia’?

Endometriosis is a common cause of pelvic pain in women, many of whom suffer a progression of symptoms over their menstrual life. Symptoms may include combinations of abnormal visceral sensations and emotional distress. Endometriosis pain, or ‘endometrialgia’ often has a negative influence on the ability to work, on family relationships and sense of worth.

Endometrialgia is often considered to be a homogeneous sensory entity, mediated by a specialised high threshold sensory system, which extends from the periphery through the spinal cord, brain stem and thalamus to the cerebral cortex. However, multiple mechanisms have been detected in the nervous system responsible for the pain including peripheral sensitisation, phenotypic switches, central sensitisation, ectopic excitability, structural reorganisation, decreased inhibition and increased facilitation, all of which may contribute to the pain.

Although the causes of endometrialgia can differ (eg inflammatory, neuropathic and functional), they share some characteristics. Endometrialgia may be evoked by a low intensity, normally innocuous stimulus (allodynia), or it may be an exaggerated and prolonged response to a noxious stimulus (hyperalgesia). The pain may also be spontaneous in the absence of any apparent peripheral stimulus.

Oestrogens and prostaglandins probably play key modulatory roles in endometriosis and endometrialgia. Consequently many of the current medical treatments for the condition include oral drugs, like non-steroid anti-inflammatory drugs, contraceptives, progestogens, androgenic agents, gonadotrophin releasing hormone analogues, as well as laparoscopic surgical excision of the endometriosis lesions. However, management of pain in women with endometriosis is currently inadequate for many. Possibly acupuncture and cognitive therapy may be used as an adjunct.

Familial aggregation of endometriosis in the Yale Series

OBJECTIVE

To investigate the familial aggregation and the risk of endometriosis among the female relatives of women with endometriosis. We also compared the epidemiologic characteristics of women with and without family history of endometriosis.

PATIENT(S)

A total of 485 women with endometriosis and 197 infertile women without endometriosis underwent surgical investigation between August 1996 and February 2002.

MAIN OUTCOME MEASURE(S)

The relative risk of endometriosis in a first-degree relative and the association between potential risk factors was estimated by chi2 and by crude adjusted odds ratios (95% CI).

RESULTS

Endometriosis was identified in 9.5% of first-degree relatives of women with endometriosis versus only 1% of controls. The odds ratio for endometriosis in a first-degree relative was 10.21 (95% CI 2.45-42.5; P<0.001). In 3.9% of cases women with endometriosis reported that their mother had been diagnosed with endometriosis and 5.6% of cases that at least one sister had been diagnosed. Compared to the control group the odds ratio for the mother having endometriosis (7.99, 95% CI 1.06-60.1) or at least one sister having (11.55, 95% CI 1.56-85.59) were significantly elevated. Among women with endometriosis who reported a family history of endometriosis, and women with endometriosis who did not report a family history of endometriosis, there were no differences in demographic characteristics, body habitus, or menstrual parameters.

CONCLUSION(S)

Women with endometriosis have a tenfold increased risk of endometriosis in their first-degree relatives.

Histone deacetylase inhibitors trichostatin A and valproic acid induce cell cycle arrest and p21 expression in immortalized human endometrial stromal cells

OBJECTIVE

Following our observation that histone deacetylase inhibitors (HDACIs) trichostatin A (TSA) and valproic acid (VPA) can suppress proliferation of endometrial stromal cells, we sought to determine whether TSA and VPA do so by inducing cell cycle arrest and p21 expression.

STUDY DESIGN

A recently established immortalized endometrial stromal cell line was treated with TSA, VPA, and/or all-trans retinoic acid (ATRA) and the consequent cell cycle progression was measured by flow cytometry and p21 protein expression by Western blot analysis.

RESULTS

Both TSA and VPA induced cell cycle arrest and p21 expression in a concentration-dependent manner. Treatment with ATRA alone also induced cell cycle arrest and moderate increase in p21 expression but joint treatment of ATRA and TSA/VPA did not further enhance cell cycle arrest as compared with TSA/VPA treatment alone.

CONCLUSIONS

HDACIs suppress proliferation of endometrial stromal cells through induction of cell cycle arrest and possibly also through apoptosis as well. RA also induces cell cycle arrest but it does not synergize with HDACIs in inducing cell cycle arrest. HDACIs may be promising compounds for treating endometriosis.