Antiangiogenic therapies in endometriosis

Nonhormonal therapy for endometriosis: a randomized, placebo-controlled, pilot study of cabergoline versus norethindrone acetate

Objective

To estimate the efficacy and safety of a novel nonhormonal therapeutic agent, cabergoline, compared with that of the standard clinical therapy, norethindrone acetate (NETA), for the treatment of endometriosis-associated pain in young women with endometriosis.

Design

Randomized, double-blind, placebo-controlled pilot study.

Setting

Tertiary care center.

Patient(s)

Women (n = 9) with surgically confirmed endometriosis.

Intervention(s)

A random, double-blind assignment to either NETA (5 mg/day) + placebo twice weekly or cabergoline (0.5 mg) twice weekly + placebo daily for 6 months.

Main Outcome Measure(s)

We collected the measures of pelvic pain and laboratory parameters every 3 months.

Result(s)

We observed a decrease in pain scores and increase in pain relief in women randomized to receive cabergoline, who appeared to show similar or more improvements than women treated with NETA. The serum measures of vascular endothelial growth factor receptor 1 declined over 6 months in those who received cabergoline. Cabergoline was well tolerated, and no serious adverse events occurred.

Conclusion(s)

Safe, effective adjunct treatments are lacking for patients with endometriosis who do not respond to standard care. Because the growth of endometriosis requires angiogenesis, blood vessel growth is an attractive therapeutic target. This pilot study suggests that cabergoline, a vascular endothelial growth factor pathway inhibitor, is an effective therapeutic option for women with chronic pain due to endometriosis. Building upon this investigation, we will conduct larger, randomized trials of cabergoline, advancing research on the best treatments for endometriosis—particularly disease resistant to hormonal therapies.

Clinical Trial Registration Number

clinicaltrials.gov; registration number NCT02542410.

Novel Medicine for Endometriosis and Its Therapeutic Effect in a Mouse Model

Current therapeutic medicines for endometriosis cannot be administered during assisted reproductive technology (ART) because they have bad effects during pregnancy. In this study, we created an animal model of endometriosis and evaluated the therapeutic effect of progestin (Dienogest), dopamine agonist (Cabergoline), and their combination (Dienogest + Cabergoline). We established a mouse model mimicking human endometriosis. The mice with endometriosis were then treated with a single drug (Dienogest or Cabergoline) or both drugs (Dienogest + Cabergoline) for 14 days. An immunohistological study was then performed to analyze inflammatory lesions in the recipient mice. Real-time polymerase chain reaction (RT-PCR) and Western blotting were also performed to determine the levels of genes and proteins in inflammatory lesions to assess the recovery of endometriosis. Histologic staining showed that all medication groups showed a clear decrease in the inflammatory phenotype in the uterus, peritoneum, and intestine. Gene and protein expression analysis showed a therapeutic effect in all medication groups. In conclusion, Cabergoline had a therapeutic effect similar to that of Dienogest and could be used as an alternative to Dienogest during ART for patients with infertility; compared to the individual drugs, the combination treatment has a synergistic effect on endometriosis.

Eutopic stromal cells of endometriosis promote neuroangiogenesis via exosome pathway†

Endometriosis is a common multifactorial gynecological disorder defined as the proliferation of endometrial tissue outside of the uterine cavity. Neuroangiogenesis (co-recruitment of nerves and blood vessels) is believed to play an integral part in the establishment and growth of endometriotic lesions. We hypothesized that exosomes derived from abnormal endometrium may serve as the second identifier of endometriosis and play an important role in the development of endometriosis by regulating neuroangiogenesis. Primary human endometrial stromal cells (ESCs) were isolated from eutopic endometrium (EmESC, n = 22) with endometriosis and normal endometrium (CoESC, n = 6). Exosomes were isolated from ESCs using the "standard" ultracentrifugation method, and the characterization of exosomes was identified through transmission electron microscopy, nanoparticle tracking analysis, and western blot. The role of exosomes in regulating neuroangiogenesis was determined through in vitro tube formation assay, neurite outgrowth assay, and dorsal root ganglion (DRG) neuron apoptosis analysis. The data showed that EmESCs could secrete exosomes with a diameter of approximately 100 nm and a biconcave morphological feature; they were internalized by human umbilical vein endothelial cells and DRG neurons and enhanced neuroangiogenic effects. We further validated the role of exosomes through blocking experiments. We found that when the exosome secretion was blocked, the pro-neuroangiogenesis effects were decreased. In conclusion, these data suggested that exosomes may play a key role in endometriosis by promoting neuroangiogenesis.

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.

Power of proteomics in linking oxidative stress and female infertility

Endometriosis, PCOS, and unexplained infertility are currently the most common diseases rendering large numbers of women infertile worldwide. Oxidative stress, due to its deleterious effects on proteins and nucleic acids, is postulated to be the one of the important mechanistic pathways in differential expression of proteins and in these diseases. The emerging field of proteomics has allowed identification of proteins involved in cell cycle, as antioxidants, extracellular matrix (ECM), cytoskeleton, and their linkage to oxidative stress in female infertility related diseases. The aim of this paper is to assess the association of oxidative stress and protein expression in the reproductive microenvironments such as endometrial fluid, peritoneal fluid, and follicular fluid, as well as reproductive tissues and serum. The review also highlights the literature that proposes the use of the fertility related proteins as potential biomarkers for noninvasive and early diagnosis of the aforementioned diseases rather than utilizing the more invasive methods used currently. The review will highlight the power of proteomic profiles identified in infertility related disease conditions and their linkage with underlying oxidative stress. The power of proteomics will be reviewed with regard to eliciting molecular mechanisms for early detection and management of these infertility related conditions.

Endostatin Gene Therapy for Endometriosis in Rats

Objective:

Endostatin gene therapy for endometriosis was studied in an experimental autotransplantation model in rats.

Methods:

Endometriotic lesions were transfected by intralesional injection of the plasmid lipofectamine-endostatinpBud (group 1), lipofectamine-pBud (empty vector; group 2) or phosphatebuffered saline (group 3). Endostatin mRNA and protein levels in lesions were evaluated by quantitative real-time reverse transcription-polymerase chain reaction and Western blot analysis. Endostatin and vascular endothelial growth factor (VEGF) protein levels in serum, and microvessel density (MVD) and matrix metalloproteinase (MMP)-2 protein levels in endometriotic lesions, were also determined.

Results:

Lipofectamine- endostatin-pBud injection increased endostatin mRNA and protein levels in lesions. Lesions were significantly smaller, and serum VEGF levels significantly lower, in group 1 versus controls. Serum VEGF was significantly and negatively correlated with serum endostatin. In group 1, MMP-2 levels and MVD were significantly lower versus controls. MMP-2 level was negatively correlated with endostatin.

Conclusions:

Gene therapy with endostatin appears to be an effective treatment for endometriosis. Restoration of endostatin gene expression by gene transfer in vivo might be a potential gene therapy approach for human endometriosis.

Slit2 overexpression results in increased microvessel density and lesion size in mice with induced endometriosis

We recently reported that Slit/Roundabout (ROBO) 1 pathway may be a constituent biomarker for recurrence of endometriosis, likely through promoting angiogenesis. In this study, we sought to determine as whether Slit2 overexpression can facilitate angiogenesis, increase lesion size, and induce hyperalgesia in mice with induced endometriosis. We used 30 Slit2 transgenic (S) and 29 wild-type (W) mice and cross-transplanted endometrial fragments from S to W (group SW) and vice versa (group WS), and also within the S and W (groups SS and WW, respectively), into the peritoneal cavity, inducing endometriosis. We also performed a sham surgery within both S and W mice (groups Sm and Wm, respectively). The size of the ectopic implants, microvessel density (MVD) and immunoreactivity to ROBO1, and vascular endothelial cell growth factor (VEGF) in ectopic and eutopic endometrium, along with hotplate and tail-flick tests in all mice, were then evaluated. We found that the induction of endometriosis resulted in generalized hyperalgesia, which was unaffected by Slit2 overexpression. Slit2 overexpression did increase the lesion size significantly and correlated positively with the MVD in ectopic and eutopic endometrium. Slit2 expression levels appear to correlate with the MVD, but not with VEGF immunoreactivity, in ectopic endometrium. Consequently, we conclude that Slit2 may play an important role in angiogenesis in endometriosis. The increased angiogenesis, as measured by MVD, but not VEGF immunoreactivity, likely resulted in increased lesion size in induced endometriosis. Thus, SLIT2/ROBO1 pathway may be a potential therapeutic target for treating endometriosis.

XRCC1 399 Arg-related genotype and allele, but not XRCC1 His107Arg, XRCC1 Trp194Arg, KCNQ2, AT1R, and hOGG1 polymorphisms, are associated with higher susceptibility of endometriosis

X-ray repair cross-complementing group 1 (XRCC1) and human 8-oxoguanine glycosylase 1 (hOGG1) play important roles in base excision repair. KCNQ genes comprising voltage-gated ion-channels related with cell stability. Angiotensin II type 1 receptor (AT1R) is related with angiogenesis, which influence endometriosis growth, invasion and regression. We aimed to investigate whether these polymorphisms were associated with endometriosis susceptibility. Women were divided [ 1 ]: endometriosis (n = 136 [ 2 ]); non-endometriosis groups (n = 112). XRCC1 (codon 107, 194, 399), hOGG1, KCNQ2, AT1R polymorphisms were amplified by PCR and detected by electrophoresis after restriction enzyme (RsaI, HpaII, MspI, Fnu4HI, Ava II, Dde I) digestions. Genotypes and allelic frequencies in both groups were compared. Proportions of XRCC1 Arg399Gln*GG/GA/AA and G/A allele between both groups were [ 1 ]: 41.9/53.7/4.4% and 68.8/31.2% [ 2 ]; 30.4/54.5/15.1% and 57.6/42.4% (p < 0.05). Other 5 polymorphisms (XRCC1 codon 107 and 194, hOGG1, KCNQ2, and AT1R) between both groups were non-significantly different. Proportions of XRCC1 107*AA/AG/GG and XRCC1 194*TT/TC/CC between both groups were [ 1 ]: 3.7/27.2/69.1% and 5.8/34.6/59.6% [ 2 ]; 2.6/21.4/75.8% and 11.6/37.5/50.9%. HOGG1*CC/CG/GG, KCNQ2*AA/AC/CCC and AT1R*AA/AC/CC were [ 1 ]: 14.8/42.6/42.6, 14/41.9/44.1 and 92.6/7.4/0% [ 2 ]; 11.6/50/38.4, 17/50/33 and 100/0/0%. We concluded that XRCC1 399 Arg-related genotype and allele are correlated with higher susceptibility to endometriosis, which suggested its association with endometriosis pathogenesis. XRCC1 107 and 194, hOGG1, KCNQ2, and AT1R are not associated with endometriosis susceptibility.

Novel therapies targeting endometriosis

Endometriosis is an often painful disorder in which the endometrial glands and stroma grow outside the uterus. The disease affects women's quality of life and is a common cause of infertility. In this review, we describe promising new developments in the field based on in vitro assays and rodent models, each of which has the potential to be beneficial in the treatment of this disease. We will specifically describe the role of anti-inflammatory drugs, selective estrogen, or progesterone modulators, statins, antiangiogenic agents, and the potential for targeting stem cells as likely methods to hone in and eliminate endometriosis. The most promising of these potential therapies are currently slated for further testing in both rodent and nonhuman primate trials.

Current pharmacotherapy for endometriosis

IMPORTANCE OF THE FIELD

Medical therapy is the most commonly used treatment for endometriosis. In particular, the administration of hormonal therapies aims to improve symptoms with minimal adverse effects.

AREAS COVERED IN THIS REVIEW

Observational and randomized studies evaluating the efficacy of medical therapy on symptoms associated with endometriosis were reviewed. We searched Medline, Embase and the Cochrane Library up to December 2009.

WHAT THE READER WILL GAIN

The reader will obtain information on the available medical therapies used to treat endometriosis-related symptoms either after surgery or as an alternative to the surgical excision of endometriosis. The effectiveness of therapies, the dose of drugs, the length of treatment and the adverse effects are examined.

TAKE HOME MESSAGE

Medical therapies can efficaciously reduce the severity of pain symptoms caused by endometriosis. Recurrence of symptoms is common after discontinuation of medical therapies; therefore, the choice of the therapy should be based not only on the improvements of symptoms but also on the potential adverse effects and patients' satisfaction.

Pharmacological treatment of endometriosis: experience with aromatase inhibitors

Current treatment of endometriosis is mainly based on surgery and ovarian suppressive agents. In the last 10 years, it has been demonstrated that aromatase P450, a key enzyme for estrogen biosynthesis, may have a pathogenic role in endometriosis because it is aberrantly expressed in endometriotic implants and in eutopic endometrium of women with endometriosis. Therefore, inhibition of aromatase activity may represent a new therapeutic option for endometriosis. Case reports and observational studies have shown that pain symptoms caused by endometriosis quickly improve after administration of aromatase inhibitors. Limited data are available on the long-term course of pain symptoms after completion of treatment with aromatase inhibitors; however, some recent studies suggest that symptoms may recur at short-term follow-up. A range of results are reported on the effects of aromatase inhibitors on endometriotic lesions, with some authors describing improvements and other authors reporting persistence of pelvic lesions at second-look laparoscopy after treatment. No severe adverse effect has been reported during treatment with aromatase inhibitors both in pre- and postmenopausal women. On the basis of the available data, administration of aromatase inhibitors should now be offered only to the small number of women who have severe pain despite previous surgical and hormonal therapies. Further research in the form of randomized controlled trials will be required before recommending the routine use of these agents.

XRCC4 codon 247*A and XRCC4 promoter -1394*T related genotypes but not XRCC4 intron 3 gene polymorphism are associated with higher susceptibility for endometriosis

DNA repair systems act to maintain genome integrity in the face of replication errors, environmental insults, and the cumulative effects of age. Genetic variants in DNA repair genes such as X-ray repair cross-complementing group 4 (XRCC4) might influence the ability to repair damaged DNA. Herein we aimed to investigate whether some XRCC4-related polymorphisms were associated with endometriosis susceptibility. Women were divided: (1) severe endometriosis (rAFS stage IV, n = 136) and (2) nonendometriosis groups (n = 112). The polymorphisms of XRCC4 codon 247, XRCC4 promoter -1394, and XRCC4 intron 3 insertion/deletion (I/D) polymorphism were amplified by PCR and detected by electrophoresis after restriction enzyme (BBS I, Hinc II) digestions. Genotypes and allelic frequencies in both groups were compared. We observed that XRCC4 codon 247*A and XRCC4 promoter -1394*T related genotypes, but not XRCC4 intron 3 I/D polymorphism, are associated with higher susceptibility for endometriosis. Distributions of XRCC4 codon 247*C homozygote/heterozygote/A homozygote, and C/A allele in both groups were: (1) 89/9.5/1.5% and 93.7/6.3%; (2) 97.3/2.7/0%, and 98.7/1.3% (P < 0.05). Proportions of XRCC4 promoter -1394*T homozygote/heterozygote/G homozygote and T/G allele in both groups were: (1) 94.1/5.2/0.7% and 96.7/3.3%, and (2) 79.4/17.9/2.7% and 88.4/11.6% (P < 0.005). Proportions of XRCC4*I homozygote/heterozygote/D homozygote and A/C allele in both groups were: (1) 67.6/30.9/1.5% and 83.2/16.8%, and (2) 70.5/24.1/5.4% and 82.6/17.4% (nondifference). We conclude that XRCC4 codon 247*A and XRCC4 promoter -1394*T related genotypes and alleles, but not XRCC4 intron 3 I/D polymorphism, might be associated with endometriosis susceptibilities and pathogenesis.

Epigallocatechin-3-gallate inhibits estrogen-induced activation of endometrial cells in vitro and causes regression of endometriotic lesions in vivo

BACKGROUND

Epigallocatechin-3-gallate (EGCG), the major component of green tea, is a pleiotropic substance, which may inhibit tumor growth via multiple intracellular signaling pathways. Herein, we studied whether EGCG may also be effective in the treatment of endometriosis.

METHODS

We investigated the effect of EGCG on activation by estradiol (E(2)), proliferation and vascular endothelial growth factor (VEGF) expression of isolated hamster endometrial stromal cells and glandular cells in vitro using the water-soluble tetrazolium (WST)-1 colorimetric assay and western blot analysis. In the dorsal skinfold chamber model of Syrian golden hamsters, which were treated for 14 days with EGCG or vehicle, we further analyzed angiogenesis, blood perfusion and tissue integrity of both endometriotic lesions and ovarian follicles by intravital fluorescence microscopy and histology.

RESULTS

We found that EGCG suppresses E(2)-stimulated activation, proliferation and VEGF expression of endometrial cells in vitro (all P < 0.05). Furthermore, EGCG selectively inhibited angiogenesis and blood perfusion (P < 0.05) of endometriotic lesions in vivo without affecting blood vessel development in ovarian follicles. Histology confirmed that EGCG-treatment induces regression of the endometriotic lesions.

CONCLUSIONS

Our data indicate that EGCG might be a promising therapeutic agent in the treatment of endometriosis, preventing the establishment of new endometriotic lesions.

Angiogenesis and antiangiogenic therapy in endometriosis

Endometriosis, the presence of endometrium-like tissue outside of the uterine cavity, is a common disease among women of reproductive age. Typical symptoms include abdominal pain and painful menstruation. In addition, endometriosis is associated with reduced fertility. Current treatment modalities, the surgical removal of endometriotic lesions and the hormonal suppression of estrogen are associated with significant morbidity, side-effects and recurrence rates. Despite uncertainties about the pathophysiology of the disease it has recently become apparent that angiogenesis plays a pivotal role in endometriosis. This review focuses on a multitude of factors involved in the angiogenic phenotype of endometriosis demonstrating that many biological systems such as the immune system and steroid hormones are closely connected to angiogenic pathways in this disease. In addition, experimental and clinical data are discussed that concentrate on the inhibition of angiogenesis as a novel therapeutic approach for endometriosis.

In vitro and in vivo approaches to study angiogenesis in the pathophysiology and therapy of endometriosis

Endometriosis represents one of the most common gynaecological disorders. According to the implantation theory, angiogenesis is a major prerequisite for the initiation and progression of the disease. Thus, during the last decade, many studies have focused on the mechanisms regulating angiogenesis in endometriotic lesions. For this purpose, sophisticated in vitro and in vivo approaches have been established, which are highlighted in this review. Enzyme-linked immunosorbent assays demonstrate the imbalance of pro- and anti-angiogenic growth factors in isolated peritoneal fluid from endometriosis patients. Histological, immunohistochemical and gene expression analyses of endometriotic tissue provide detailed information on the angio-architecture of endometriotic lesions and the different growth factor expression by various cell populations. Moreover, cell culture systems are useful tools for the identification of hormonal and immunological factors involved in the angiogenic process. Finally, sophisticated in vivo models, such as rodent models of peritoneal endometriosis as well as the chorioallantoic membrane assay and the dorsal skinfold chamber, allow for the detailed analysis of blood vessel development in ectopic endometrium and the efficacy of angiogenesis inhibitors. The findings resulting from all these approaches will help to provide better insights into the pathophysiology of endometriosis and to establish new anti-angiogenic treatment strategies for the future.