The role of progestins in treating the pain of endometriosis

Endometriosis

Pelvic endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects primarily pelvic tissues, including the ovaries. It is caused when shed endometrial tissue travels retrograde into the lower abdominal cavity. Endometriosis is the most common cause of chronic pelvic pain in women and is associated with infertility. The underlying pathologic mechanisms in the intracavitary endometrium and extrauterine endometriotic tissue involve defectively programmed endometrial mesenchymal progenitor/stem cells. Although endometriotic stromal cells, which compose the bulk of endometriotic lesions, do not carry somatic mutations, they demonstrate specific epigenetic abnormalities that alter expression of key transcription factors. For example, GATA-binding factor-6 overexpression transforms an endometrial stromal cell to an endometriotic phenotype, and steroidogenic factor-1 overexpression causes excessive production of estrogen, which drives inflammation via pathologically high levels of estrogen receptor-β. Progesterone receptor deficiency causes progesterone resistance. Populations of endometrial and endometriotic epithelial cells also harbor multiple cancer driver mutations, such as KRAS, which may be associated with the establishment of pelvic endometriosis or ovarian cancer. It is not known how interactions between epigenomically defective stromal cells and the mutated genes in epithelial cells contribute to the pathogenesis of endometriosis. Endometriosis-associated pelvic pain is managed by suppression of ovulatory menses and estrogen production, cyclooxygenase inhibitors, and surgical removal of pelvic lesions, and in vitro fertilization is frequently used to overcome infertility. Although novel targeted treatments are becoming available, as endometriosis pathophysiology is better understood, preventive approaches such as long-term ovulation suppression may play a critical role in the future.

Progestins for the Treatment of Endometriosis: An Update

Endometriosis is a gynecological condition that affects approximately 10% of women of reproductive age, including 25–40% of infertile women. Dysmenorrhea, dyspareunia and chronic pelvic pain are the most common symptoms. Currently available medical therapies for endometriosis do not cure the disease, but are directed at symptom relief, typically utilizing the hormone responsiveness of endometriotic tissue to induce lesion atrophy. Unfortunately, pain relapse after treatment suspension is a common event. Treatment with pharmacological therapies for endometriosis should be conceived in terms of years, thus agents that must be withdrawn after a few months due to poor tolerability or severe metabolic side effects do not greatly benefit women with symptomatic endometriosis. The characteristics of progestins render this class an ideal pharmacological choice for administration over extended periods. The present paper will review the rationale for using progestins and their mechanism of action in endometriosis. Thereafter, the results obtained by various progestins in the treatment of endometriosis will be evaluated (danazol, gestrinone, norethisterone acetate, desogestrel, cyproterone acetate, megestrol acetate, medroxyprogesterone acetate, and levonorgestrel). A progestin called dienogest, recently introduced for the treatment of endometriosis, will be given special focus, describing its mechanism of action and clinical results.

Use of medroxyprogesterone acetate in women with ovarian endometriosis undergoing controlled ovarian hyperstimulation for in vitro fertilization

This study investigated the use of medroxyprogesterone acetate (MPA) or a short protocol for controlled ovarian hyperstimulation (COH) in patients with advanced endometriosis who have normal ovarian function, and to compare cycle characteristics and pregnancy outcomes after frozen-thawed embryo transfer (FET). This was a retrospective case-control study of 244 patients with advanced endometriosis undering COH. The patients were allocated to three groups: the surgery group with MPA COH (62 patients, 71 IVF/ICSI cycles, 78 FET cycles); the aspiration group with MPA COH (85 patients had ovarian “chocolate” cysts (>3 cm) aspirated, 90 IVF/ICSI cycles, 76 FET cycles); and the short protocol group (97 patients, 101 IVF/ICSI cycles, 51 FET cycles). The results showed that higher rates of mature oocyte, D3 high quality embryo, hMG dose were observed in the two study groups using MPA compared with the short protocol. The number of >10–14 mm follicles on the trigger day, D3 top-quality embryos, viable embryos, rates of cancellation, fertilization, implantation, pregnancy outcomes were similar among the three groups. The oocytes, embryos, and pregnancy outcomes were not influenced by endometrioma surgery or presence of endometrioma. MPA COH could be effective for women with ovarian advanced endometriosis who had normal ovarian function.

Postoperative desogestrel for pelvic endometriosis-related pain: a randomized controlled trial

OBJECTIVE

To determine the effectiveness of desogestrel for relieving endometriosis-related pain.

METHODS

A double-blinded randomized placebo-controlled trial was conducted in 40 patients who had endometriosis with moderate-to-severe dysmenorrhea or chronic pelvic pain undergoing laparoscopic conservative surgery. After surgery, patients were randomized to desogestrel or placebo group. Outcomes included changes in visual analog scale (VAS) of dysmenorrhea, pelvic pain and dyspareunia, patient satisfaction, and adverse effects.

RESULTS

Forty patients were randomized to desogestrel group (n = 20) and placebo group (n = 20). At month 6, the desogestrel group had significantly lower median VAS of overall pelvic pain, dysmenorrhea and noncyclic pelvic pain. Comparing with the placebo group, the desogestrel group had greater reduction in VAS of overall pain, dysmenorrhea and pelvic pain, but comparable reduction in VAS of dyspareunia. No patient in the desogestrel group but 4 patients in the placebo group still had moderate-to-severe pelvic pain at 6 months postoperatively. The proportion of patients who rated the treatment as very satisfied was higher in the desogestrel group than in the placebo group. There was no serious adverse event during the study period.

CONCLUSIONS

Desogestrel is effective and acceptable for postoperative therapy for patients with moderate-to-severe pain related to endometriosis.

Therapeutic effects of mifepristone combined with Gestrinone on patients with endometriosis

Objective:

To evaluate the clinical therapeutic effects of mifepristone combined with gestrinone on patients with endometriosis.

Methods:

A total of 150 endometriotic patients treated in our hospital between January 2014 and December 2015 were randomly divided into a control group and a treatment group (n=75). The control group began to orally take gestrinone capsules on the second day after menstruation started (2.5 mg/time, twice/week). The treatment group orally took mifepristone tablets (12.5 mg/time, once/day), and the dosage and administration of gestrinone capsules were the same as those of the control group. After 24 weeks of consecutive treatment, the clinical therapeutic effects of the two groups were assessed, and the pelvic symptom score, clinical sign score, serum sex hormone levels and pregnancy outcomes were compared.

Results:

The total effective rates of control and treatment groups were 77.3% and 90.7% respectively, between which the difference was statistically significant (P<0.05). After treatment, the scores of pelvic symptoms (dysmenorrhea, dyspareunia, pelvic pain) and clinical signs (pelvic tenderness, induration) significantly reduced (P<0.05). Each score of the treatment group decreased more significantly than that of the control group did (P<0.05). The serum follicle hormone, luteinizing hormone, estrogen and progesterone levels were significantly lower than those before treatment (P<0.05). Each level of the treatment group dropped more significantly than that of the control group did (P<0.05). The pregnancy rates in the 6th and 12th months of follow-up were 28.0% and 13.3% in the control group respectively, and 42.7% and 29.3% in the treatment group respectively. Such rates of the two groups were significantly different at each follow-up time point (P<0.05).

Conclusion:

Mifepristone combined with gestrinone had satisfactory clinical therapeutic effects on endometriosis by reducing hormone levels and improving pregnancy outcomes. Therefore, this regimen is worthy of promotion and application in clinical practice.

Pathophysiology and Immune Dysfunction in Endometriosis

Endometriosis is an estrogen-dependent, chronic, proinflammatory disease prevalent in 10% of women of reproductive age worldwide. Characterized by the growth of endometrium-like tissue in aberrant locations outside of the uterus, it is responsible for symptoms including chronic pelvic pain, dysmenorrhea, and subfertility that degrade quality of life of women significantly. In Canada, direct and indirect economic cost of endometriosis amounts to 1.8 billion dollars, and this is elevated to 20 billion dollars in the United States. Despite decades of research, the etiology and pathophysiology of endometriosis still remain to be elucidated. This review aims to bring together the current understanding regarding the pathogenesis of endometriosis with specific focus on mechanisms behind vascularization of the lesions and the contribution of immune factors in facilitating lesion establishment and development. The role of hormones, immune cells, and cytokine signaling is highlighted, in addition to discussing the current pharmaceutical options available for management of pain symptoms in women with endometriosis.

Comparing treatments for endometriosis-related pain symptoms in patients with migraine without aura

Endometriosis is a gynecological disorder defined by the presence of endometrial-like tissue outside the uterus. Several studies have found an epidemiological correlation between endometriosis and migraine, probably due to the association of both diseases with female hormones. Progestins or combined oral contraceptives are the first-line medical therapy in women with endometriosis; however, it is well known that in some women the use of combined oral contraceptives could exacerbate migraine. This observation poses a challenge to clinicians who must concomitantly treat endometriosis-related symptoms and migraine. This review summarizes the available literature on the medical treatment of endometriosis in women suffering concomitant migraine without aura until March 2012. Due to the lack of available studies on this topic, it is difficult to draw definitive conclusions. Further studies evaluating hormonal therapies are needed; in particular, progestin therapy should be reconsidered in women with migraine and concomitant endometriosis.

Possible involvement of nerve growth factor in dysmenorrhea and dyspareunia associated with endometriosis

Nerve growth factor (NGF) has been recently proposed as one of the key factors responsible not only for promotion of nerve fiber growth but also for the onset and maintenance of pain in a variety of diseases. The aim of this study was to investigate the role of NGF in the pelvic pain associated with endometriosis. Tissue and peritoneal fluid samples were collected from 95 women with laparoscopically and histopathologically confirmed endometriosis and 59 control women without endometriosis. Expression levels of NGF mRNA and protein were examined using real-time RT-PCR and immunohistochemistry, respectively. Concentration of NGF in the peritoneal fluid (PF-NGF) was measured using ELISA. The degree of dyspareunia and dysmenorrhea was evaluated using a verbal rating scale. Real-time RT-PCR analysis revealed that NGF mRNA was significantly more abundant in the ovarian endometriomas and peritoneal endometriosis than in the normal control endometrium. Immunohistochemical analyses demonstrated that NGF was prominently expressed and preferentially localized to the glands of the ovarian endometriomas and peritoneal endometriosis, whereas it was only weakly detectable in the normal endometrium. Although PF-NGF was undetectable in some normal subjects and endometriosis patients, elevated PF-NGF in the peritoneal fluid was more frequently observed in endometriosis patients with severe pain than in those with less severe pain. Our results suggest that NGF produced locally in the peritoneal cavity may be involved in the generation of endometriosis-associated pelvic pain.

Noncontraceptive uses of hormonal contraception

Hormonal contraceptives are not only effective methods of birth control but also are effective at treating and/or preventing a variety of gynecologic and general disorders. Hormonal contraceptives can decrease the severity of acne, correct menstrual irregularities, treat endometriosis-associated pain, decrease bleeding associated with uterine myomas, decrease pain associated with menstrual periods, moderate symptoms associated with premenstrual syndrome, reduce menstrual migraine frequency, and increase bone mineral density as well as decrease the risk of specific cancers such as endometrial and ovarian cancer. Women need to receive this information to guide them in their decisions regarding choice of contraception as well as treatment options for gynecologic disorders.

Hormonal contraception and thrombotic risk: a multidisciplinary approach

Heightened publicity about hormonal contraception and thrombosis risk and the publication of new guidelines by the World Health Organization in 2009 and the Centers for Disease Control and Prevention in 2010 addressing this complex issue have led to multidisciplinary discussions on the special issues of adolescents cared for at our pediatric hospital. In this review of the literature and new guidelines, we have outlined our approach to the complex patients referred to our center. The relative risk of thrombosis on combined oral contraception is three- to fivefold, whereas the absolute risk for a healthy adolescent on this therapy is only 0.05% per year. This thrombotic risk is affected by estrogen dose, type of progestin, mechanism of delivery, and length of therapy. Oral progestin-only contraceptives and transdermal estradiol used for hormone replacement carry minimal or no thrombotic risk. Transdermal, vaginal, or intrauterine contraceptives and injectable progestins need further study. A personal history of thrombosis, persistent or inherited thrombophilia, and numerous lifestyle choices also influence thrombotic risk. In this summary of one hospital's approach to hormone therapies and thrombosis risk, we review relative-risk data and discuss the application of absolute risk to individual patient counseling. We outline our approach to challenging patients with a history of thrombosis, known thrombophilia, current anticoagulation, or family history of thrombosis or thrombophilia. Our multidisciplinary group has found that knowledge of the guidelines and individualized management plans have been particularly useful for informing discussions about hormonal and nonhormonal options across varied indications.

Dienogest, a synthetic progestin, inhibits prostaglandin E2 production and aromatase expression by human endometrial epithelial cells in a spheroid culture system

Prostaglandin E(2) (PGE(2)) is a major mediator in the pathophysiology, and pathogenesis of gynecological diseases associated with abnormal endometrial disease with proliferation and inflammation, such as endometriosis. In this study, we investigated the effect of dienogest, a selective progesterone receptor agonist, on PGE(2) production and the expression of aromatase, an estrogen synthase, in human immortalized endometrial epithelial cells. Compared with monolayer culture, the cells showed enhanced PGE(2) production and expression of the PGE(2) synthases cyclooxygenase-2 (COX-2), and microsomal prostaglandin E(2) synthase-1 (mPGES-1) in a spheroid culture system. Dienogest inhibited PGE(2) production and this effect was reversed by RU486, a progesterone receptor antagonist. Dienogest inhibited the PGE(2) synthases mRNA and protein expression, and the nuclear factor-κB activation. Moreover, the suppressive effect of dienogest on PGE(2) production was sustained 24h after the drug was withdrawn. Dienogest but not COX inhibitors inhibited aromatase expression. These results suggest that progesterone receptor activation reduces the gene expressions of COX-2, mPGES-1, and aromatase. Our findings suggest that the pharmacological mechanism of dienogest includes the direct inhibition of PGE(2) synthase and aromatase expression and may contribute to the therapeutic effect on the progression of endometriosis.

Krüppel-like factor 4 mediates anti-proliferative effects of progesterone with G₀/G₁ arrest in human endometrial epithelial cells

Activation of the progesterone receptor (PR) inhibits cell proliferation in various reproductive tissues. However, the molecular mechanisms underlying the regulation of cell proliferation by PR remain poorly understood. It is well established that Krüppel-like factor 4 (KLF4), a family of zinc fingercontaining transcription factors, induces cell cycle arrest in epithelial cells. In this study, we investigated whether KLF4 served as a target of PR activation during cell proliferation using human endometrial epithelial cells. PR agonists, progesterone and dienogest, were found to produce a lasting increase in the expression of KLF4 mRNA, followed by a decrease in cyclin D1 mRNA, and inhibit cell proliferation with G₀/G₁ arrest. KLF4 knockdown using KLF4 small interferingRNA abrogated the inhibition of cell proliferation by PR agonists. In addition, forced expression of KLF4 inhibited cyclin D1 promoter transactivation. These results suggest that PR agonists induce KLF4 expression and then inhibit cyclin D1 expression, and consequently inhibit cell proliferation in human endometrial epithelial cells. In terms of human reproductive tissue, KLF4 may be a factor concerning cell cycle, directly responsive to PR activation.

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.

Endometriosis: current therapies and new pharmacological developments

Endometriosis is a chronic inflammatory condition that is responsive to management with steroids. The establishment of a steady hormonal environment and inhibition of ovulation can temporarily suppress ectopic implants and reduce inflammation as well as associated pain symptoms. In terms of pharmacological management, the currently available agents are not curative, and treatment often needs to be continued for years or until pregnancy is desired. Similar efficacy has been observed from the various therapies that have been investigated for endometriosis. Accordingly, combined oral contraceptives and progestins, based on their favourable safety profile, tolerability and cost, should be considered as first-line options, as an alternative to surgery and for post-operative adjuvant use. In situations where progestins and oral contraceptives prove ineffective, are poorly tolerated or are contraindicated, gonadotrophin-releasing hormone analogues, danazol or gestrinone may be used. Future therapeutic options for managing endometriosis must compare favourably against existing agents before they can be considered for inclusion into current practice. Finally, as reproductive prognosis is not ameliorated by medical treatment, it is not indicated for women seeking conception.

Dienogest, a synthetic progestin, inhibits the proliferation of immortalized human endometrial epithelial cells with suppression of cyclin D1 gene expression

Dienogest is a specific progesterone receptor agonist with potent oral endometrial activity and is used in the treatment of endometriosis. In this study, we examined the direct effects of dienogest on the proliferation of human endometrial epithelial cells using an immortalized cell line. 5-Bromo-2'-deoxyuridine incorporation into the cells was inhibited by dienogest and by progesterone (P(4)) in dose-dependent fashion at concentrations of 10(-8) mol/l or higher. To identify the target genes of dienogest and P(4), we screened the expression of 84 genes related to cell cycle regulation by real-time polymerase chain reaction after 6 h of treatment at a concentration of 10(-7) mol/l. Results showed that only cyclin D1 expression was significantly down-regulated, although expression of the other genes did not significantly change after dienogest or P(4) treatment compared with the control. In a time-course study during the first 24 h after drug treatment, dienogest and P(4) each produced a lasting decrease in the expression of cyclin D1 mRNA, followed by a decrease in cyclin E1 mRNA but not an increase in the expression of cell cycle inhibitor genes (p21, p27 and p53). These findings suggest that dienogest directly inhibits the proliferation of human endometrial epithelial cells with suppression of cyclin D1 gene expression.

Challenges to our understanding of endometriosis pain

Endometriosis remains a diagnostic and therapeutic challenge despite decades of clinical experience and research. The multiple treatment options for endometriosis described in this symposium clearly indicate how difficult it can be to diagnose and effectively treat endometriosis with our current understanding of the disease. At least 3 major challenges to our understanding can be identified: (1) endometriosis does not always cause pain; (2) other causes of pelvic pain often coexists in patients with endometriosis; and (3) common medical and surgical treatments for endometriosis are relatively nonspecific. Insights from the articles in this symposium can help clinicians reach a new level of understanding of endometriosis and perhaps lead to more effective methods for diagnosing and treating this perplexing condition.