Ulipristal acetate: a novel option for the medical management of symptomatic uterine fibroids

Experimental and new investigational drugs for the treatment of uterine fibroids

INTRODUCTION

Uterine fibroids, the most prevalent benign tumors among reproductive-age women, pose treatment challenges that range from surgical interventions to medical therapies for symptom control. Progestins and estroprogestins effectively manage uterine bleeding by suppressing dysfunctional endometrium over fibroids. While GnRH agonists represent a crucial milestone in symptom treatment, their prolonged use results in menopausal-like symptoms and irreversible bone mineral density loss. Advancements in understanding fibroid pathophysiology have prompted the exploration of new compounds to overcome current therapy limitations.

AREAS COVERED

This manuscript offers an updated overview of investigational drugs for symptomatic uterine fibroids.

EXPERT OPINION

Despite ulipristal acetate's well-established efficacy as a selective progesterone receptor modulator (SPRM) in fibroid treatment, its prescription has declined due to the rare but severe risk of liver damage. Oral GnRH antagonists, like elagolix, relugolix, and linzagolix, with their novel pharmacodynamic properties, are gaining traction in fibroid management, inducing a dose-dependent reduction in circulating sex hormone levels. Ongoing research on natural compounds, such as vitamin D and epigallocatechin gallate (EGCG), presents emerging options for treating uterine fibroids. This evolving landscape reflects the ongoing efforts to improve therapeutic outcomes for individuals with symptomatic uterine fibroids.

Update on the Role and Regulatory Mechanism of Extracellular Matrix in the Pathogenesis of Uterine Fibroids

Uterine fibroids (UFs), also known as leiomyomas, are benign tumors of the myometrium affecting over 70% of women worldwide, particularly women of color. Although benign, UFs are associated with significant morbidity; they are the primary indication for hysterectomy and a major source of gynecologic and reproductive dysfunction, ranging from menorrhagia and pelvic pain to infertility, recurrent miscarriage, and preterm labor. So far, the molecular mechanisms underlying the pathogenesis of UFs are still quite limited. A knowledge gap needs to be filled to help develop novel strategies that will ultimately facilitate the development of therapies and improve UF patient outcomes. Excessive ECM accumulation and aberrant remodeling are crucial for fibrotic diseases and excessive ECM deposition is the central characteristics of UFs. This review summarizes the recent progress of ascertaining the biological functions and regulatory mechanisms in UFs, from the perspective of factors regulating ECM production, ECM-mediated signaling, and pharmacological drugs targeting ECM accumulation. In addition, we provide the current state of knowledge by discussing the molecular mechanisms underlying the regulation and emerging role of the extracellular matrix in the pathogenesis of UFs and in applications. Comprehensive and deeper insights into ECM-mediated alterations and interactions in cellular events will help develop novel strategies to treat patients with this common tumor.

Medical Therapy for Fibroids: What Next for Ulipristal Acetate?

Ulipristal acetate (UPA) was introduced as a novel progesterone receptor modulator as effective therapy for symptomatic fibroids. Randomised clinical trials established its effectiveness in the management of heavy menstrual bleeding due to uterine leiomyomas. The trials did not find any significant evidence of clinical harm to the participants. Recently, however, there have been reports of liver injury necessitating liver transplant in women who have had UPA treatment. This has led to the suspension of UPA as one of the medical therapies in the treatment for uterine fibroids while the European Medicines Agency (EMA) conducts a review of liver injury risk with its use. The European Medicine Agency safety committee has advised that women should stop taking 5 mg UPA and that no new patients should commence treatment with the medicine until the ongoing review is completed. In this article, we review the rise of UPA as one of the emerging medical therapies for symptomatic uterine fibroids and the subsequent reports of adverse events leading to the suspension of its use.

A randomized controlled pilot study of ulipristal acetate for abnormal bleeding among women using the 52-mg levonorgestrel intrauterine system

OBJECTIVE

To assess the efficacy of ulipristal acetate (UPA) for reducing abnormal bleeding among women using the 52-mg levonorgestrel intrauterine system (LNG-IUS).

METHODS

A randomized, double-blind, placebo-controlled pilot study conducted from September 1, 2016 to September 30, 2018, at the University of Campinas, Brazil. LNG-IUS users reporting prolonged or frequent uterine bleeding for at least 1 year were randomized to receive 5 mg UPA per day for 5 days or placebo at an identical regimen. Bleeding was recorded for 90 days after treatment began and was compared between the groups.

RESULTS

Of 94 eligible women, 64 with abnormal bleeding associated with LNG-IUS use declined treatment or device removal after counselling regarding anticipated bleeding patterns. For the 25 study participants, differences were nonsignificant between the UPA and placebo groups for number of days before bleeding stopped and days free of bleeding; however, UPA users displayed a trend for shorter duration before bleeding stopped and longer time free of bleeding. A similar trend for mean number of bleeding days at 30-, 60-, and 90-day follow-up was observed.

CONCLUSION

A nonsignificant trend in reduction of abnormal bleeding was observed among LNG-IUS users taking 5 mg UPA per day for 5 days compared with placebo; however, further research is needed. CLINICALTRIALS.GOV: NCT03186586.

Selective progesterone receptor modulators for fertility preservation in women with symptomatic uterine fibroids

Uterine fibroids (UFs, AKA leiomyoma) are the most important benign neoplastic threat to women's health, with costs up to hundreds of billions of health care dollars worldwide. Uterine fibroids caused morbidities exert a tremendous health toll, impacting the quality of life of women of all ethnicities, especially women of color. Clinical presentations include heavy vaginal bleeding, pelvic pain, bulk symptoms, subfertility, and obstetric complications. Current management strategies heavily lean toward surgical procedures; nonetheless, the choice of treatment is generally subject to patient's age and her desire to preserve future fertility. Women with UF who desire to maintain future fertility potential face a dilemma because of the limited treatment choices that are currently available to help them achieve that goal. Recently, ulipristal acetate the first of the promising family of oral selective progesterone receptor modulators has been approved for UF treatment in Europe, Canada, and several other countries and is under review for possible approval in the USA. In this review article, we discuss recent advances in the management options against UF with a bend toward oral effective long-term treatment alternatives who are particularly suited for those seeking to preserve their future fertility potential. We also explore the transformative concept of primary and secondary UF prevention using these new anti-UF agents. We envision a remarkable shift in the management of UF in future years from surgical/invasive treatment to orally administrated options; clearly, this potential shift will require additional intense clinical research.

Identification and bioinformatics analysis of overlapping differentially expressed genes in depression, papillary thyroid cancer and uterine fibroids

It is hypothesized that there may be common characteristics between the genetic regulatory networks of different diseases. To identify these potential similarities, analysis of overlapping differentially expressed genes (DEGs) in several diseases, which are believed to be associated in traditional Chinese medicine (TCM) was performed in the present study. The gene expression profiles associated with depression, papillary thyroid carcinoma (PTC) and uterine fibroids (UF) were preliminarily analyzed using Gene Expression Omnibus 2R tools. Gene Ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis and protein-protein interaction network analysis of the overlapping DEGs in depression, PTC and UF was performed. The results indicated that multiple genes, including activating transcription factor 3 and WSC domain containing 2 and the phosphoinositide 3 kinase/protein kinase b signaling pathway and its downstream effectors may be common factors associated with depression, PTC and/or UF. The neuroendocrine functions of the hypothalamic-pituitary-ovarian axis and hypothalamic-pituitary-thyroid axis were also identified as being mutually associated with depression, PTC and/or UF. However, due to the limitations of DNA microassays, it is recommended that future studies take epigenetics into consideration. Further transcriptomic, methylomic and metabolomic analyses of depression, PTC and UF are also required to identify and elucidate the key associated biomarkers. In conclusion, the results of the current study shed light on the potential genetic interconnections between depression, PTC and UF, which may be beneficial for understanding their underlying coregulatory mechanisms and contributing to the development of homeotherapy based on bioinformatics prediction.

Predictive factor for volume reduction of uterine fibroids after short-term use of ulipristal acetate

OBJECTIVES

Ulipristal acetate (UPA) is a selective progesterone receptor modulator, which has been used to treat uterine fibroids. Many published reports about the outcomes indicate effective control of bleeding and reduction in the fibroid volume following both short- and long-term therapy. However, the reported volume reduction varies across different reports. Therefore, the purpose of this study was to investigate the factors that can affect the volume reduction of uterine fibroids, after short-term UPA therapy in patients with symptomatic uterine fibroids.

STUDY DESIGN

Women treated with UPA for 3 months, between November 2013 and February 2017, for symptomatic uterine fibroids were evaluated retrospectively. The fibroid volume was measured using ultrasonography or magnetic resonance imaging. Response was defined as any reduction in volume after treatment and non-response was defined as no change or increase in volume.

RESULTS

Totally, 152 women were treated with UPA and the median volume reduction was 13.1% (interquartile range [IQR] -16.8 to 36.7). Response to treatment was seen in 92 of 152 (60.5%) patients, while 60 women (39.5%) showed no response. Median number of fibroids in the response group was less than that in the non-response group (P = 0.030; median 2, IQR 1-4 vs. median 4, IQR 1-6). On multivariate regression analysis, fewer number of uterine fibroids was an independent factor for predicting a good response to UPA (odds ratio 0.830, CI: 0.710-0.969, P = 0.019).

CONCLUSION

An independent factor that can affect the volume reduction after a 3-month UPA therapy in women with uterine fibroids was the number of fibroids. This indicates that UPA might be ineffective for volume reduction in cases with multiple leiomyomas. However, future prospective studies comparing solitary and multiple leiomyomas for response to UPA are necessary.

Successes and failures of uterine leiomyoma drug discovery

INTRODUCTION

To-date, the only cure for symptomatic uterine fibroids (UFs) is surgical intervention. However, surgery may eliminate the hope of future pregnancies; moreover, the intrinsic risks of surgery make it a less favorable to women with UFs. Because of this, conservative medical therapies have become an attractive and prior option for those women. Leuprolide acetate (LA), a gonadotropin-releasing hormone (GnRH) agonist, is the only pharmacological agent currently approved for the short-term and pre-operative management of symptomatic UFs in the USA. Areas covered: This systematic review covers the successes and failures of prominent drugs that have been researched for UFs in the past and agents that have shown promise in recent clinical trials. The most recent clinical trials and advances in drug therapy are presented in a comprehensive overview outlining the direction UF drug discovery is heading. Expert opinion: Experts in the field are already on the forefront leading the responsibility to uncover potential drugs as long term fertility friendly viable options for non-invasive treatment/prevention of UFs. Indeed, a shift in the UF management is expected in the future.

Ulipristal acetate for pre-operative treatment of moderate-to-severe uterine fibroids in women of reproductive age in The Netherlands: cost minimization analysis and budget impact analysis

OBJECTIVE

Ulipristal acetate has been found to be non-inferior to other pre-operative treatments of uterine fibroids, particularly leuprolide. The objective of this study was to assess the pharmacoeconomic profile of ulipristal acetate compared to leuprolide for the pre-operative treatment of moderate-to-severe uterine fibroids in women of reproductive age in The Netherlands. The analysis was performed and applied within the framework of the ulipristal acetate submission for reimbursement in 2012.

METHODS

A decision model was developed to compare the total costs of ulipristal acetate compared to leuprolide, the standard care in The Netherlands. The target population of this study corresponded to the type of patients included in the PEARL II clinical trial; i.e. women of reproductive age requiring pre-operative treatment for uterine fibroids. Sensitivity analysis was implemented to assess uncertainties. Data regarding costs, effects, and other input parameters were obtained from relevant published literatures, the Dutch Healthcare Insurance Board, and expert opinion obtained by means of a panel of experts from several medical centers in The Netherlands.

RESULTS

In The Netherlands, the total costs of ulipristal acetate and leuprolide were estimated at €4,216,027 and €4,218,095, respectively. The annual savings of ulipristal acetate were, therefore, estimated at €2,068. The major driver of this cost difference was the cost of administration for leuprolide. Sensitivity analyses showed that ulipristal acetate mostly remained cost-saving over a range of assumptions. The budget impact analysis indicated that the introduction of ulipristal acetate was estimated to result in cost savings in the first 3 years following the introduction. The results of this study were used in the decision on reimbursement of ulipristal acetate according to the Dutch Reference Pricing system in 2012.

CONCLUSION

Ulipristal acetate was cost saving compared to leuprolide and has the potential to provide substantial savings on the healthcare budget in The Netherlands.

Uterine fibroid shrinkage after short-term use of selective progesterone receptor modulator or gonadotropin-releasing hormone agonist

Objective

The aim of this study was to evaluate the effect of short-term use of selective progesterone receptor modulator (SPRM) or gonadotropin-releasing hormone (GnRH) agonist on uterine fibroid shrinkage among Korean women.

Methods

This retrospective study involved 101 women with symptomatic uterine fibroids who received ulipristal acetate (SPRM, n=51) and leuprolide acetate (GnRH agonist, n=50) for 3 months between November 2013 and February 2015. The fibroid volume was measured both before and after treatment using ultrasonography, computed tomography, and magnetic resonance imaging. The outcomes were compared between the SPRM and GnRH agonist groups.

Results

The median rate of fibroid volume reduction after SPRM treatment was 12.4% (IQR −14.5% to 40.5%) which was significantly lower than the reduction rate observed after GnRH agonist treatment (median 34.9%, IQR 14.7% to 48.6%, P=0.004). 19 of 51 (37.3%) patients with SPRM treatment did not show any response of volume shrinkage, while 7 of 50 (14.0%) women with GnRH agonist showed no response (P=0.007).

Conclusion

Short-term SPRM treatment yields lower volume reduction than GnRH agonist treatment in Korean women with symptomatic fibroids. Further large-scale randomized trials are needed to confirm our findings.

Oestrogen-induced angiogenesis and implantation contribute to the development of parasitic myomas after laparoscopic morcellation

BACKGROUND

Iatrogenic parasitic myomas (PMs), caused by intra-corporeal power morcellation during laparoscopy is gradually increasing. However, the pathogenesis and medical treatment of PMs remain largely unelucidated.

METHODS

Laparoscopically-induced PM xenografted mouse model was conducted by xenografting human uterine myoma fragments into the abdominal cavity of SCID mice and hormonal manipulation was performed using this mouse model to demonstrate the role of oestrogen in the development of implanted PMs. Immunohistochemistry of oestrogen receptor α (ERα), progesterone receptor (PR), vimentin, vascular endothelial growth factor (VEGF), microvessel density (MVD) and Ki-67 index was performed and compared.

RESULTS

In the patient with PMs, ERα, PR, angiogenesis and proliferative property expression were upregulated in PM lesions compared to uterine myomas. In the laparoscopically-induced PM mouse model, implanted myomas had more steroid receptor expressions, angiogenesis and proliferative property compared with pre-xenografted or non-implanted myoma. Depletion of oestrogen in the ovariectomized (OVX) mice decreased laparoscopically-induced PM implantations. In comparison, the implantations of PMs were increased with additional E2 supplement. Hormonal manipulation in the PM mouse model, including AI, GnRHa and SERM groups, were compared and AI significantly decreased the implantations, steroid receptor, angiogenesis, cell density, and proliferative index of PMs compared with control group. Furthermore, GnRHa significantly decreased VEGF and MVD expressions compared with control group.

CONCLUSIONS

These data highlight the crucial role of oestrogen in the development of laparoscopically-induced PMs and suggest that hormone manipulation may be a potential therapeutic agent.

TRIAL REGISTRATION

This protocol was approved by the Human and Animal Institutional Review Board of Taipei Veterans General Hospital ( VGHIRB No 2014-10-002C on Nov. 17^th, 2014; IACUC 2014-119 on Aug. 22^nd, 2014).

Endocrinology of uterine fibroids: steroid hormones, stem cells, and genetic contribution

PURPOSE OF REVIEW

Uterine fibroids are extremely common, and can cause significant morbidity, yet the exact cause of these tumors remains elusive and there are currently no long-term treatments available. In this review, we aim to provide an overview of steroid hormones, genetic abnormalities, and stem cells in the pathogenesis of uterine fibroids.

RECENT FINDINGS

A universal feature of fibroids is responsiveness to estrogen and progesterone, and most of the currently available therapies exploit this characteristic. Ulipristal acetate has recently shown particular promise for providing long-term relief from uterine fibroids. Additionally, fibroid stem cells were isolated and appear to be necessary for growth. The recent discovery of somatic mutations involving mediator subunit complex 12 (MED12) or high-mobility group AT-hook 2 (HMGA2) in the majority of fibroids and the links to their pathophysiology were also significant advances.

SUMMARY

The recent shift in focus from hormones to fibroid stem cells and genetic aberrations should lead not only to a deeper understanding of the specific cause of fibroids, but also to the discovery of new therapeutic targets. Targeting the products of genetic mutations or fibroid stem cells has the potential to achieve both better control of current tumors and the prevention of new fibroids.

The medical management of abnormal uterine bleeding in reproductive-aged women

In the treatment of women with abnormal uterine bleeding, once a thorough history, physical examination, and indicated imaging studies are performed and all significant structural causes are excluded, medical management is the first-line approach. Determining the acuity of the bleeding, the patient's medical history, assessing risk factors, and establishing a diagnosis will individualize their medical regimen. In acute abnormal uterine bleeding with a normal uterus, parenteral estrogen, a multidose combined oral contraceptive regimen, a multidose progestin-only regimen, and tranexamic acid are all viable options, given the appropriate clinical scenario. Heavy menstrual bleeding can be treated with a levonorgestrel-releasing intrauterine system, combined oral contraceptives, continuous oral progestins, and tranexamic acid with high efficacy. Nonsteroidal antiinflammatory drugs may be utilized with hormonal methods and tranexamic acid to decrease menstrual bleeding. Gonadotropin-releasing hormone agonists are indicated in patients with leiomyoma and abnormal uterine bleeding in preparation for surgical interventions. In women with inherited bleeding disorders all hormonal methods as well as tranexamic acid can be used to treat abnormal uterine bleeding. Women on anticoagulation therapy should consider using progestin-only methods as well as a gonadotropin-releasing hormone agonist to treat their heavy menstrual bleeding. Given these myriad options for medical treatment of abnormal uterine bleeding, many patients may avoid surgical intervention.

Ulipristal acetate for use in moderate to severe symptoms of uterine fibroids

Although it has been known for a long time that uterine fibroids respond to changes in sex steroid concentrations, it is the availability of selective progesterone receptor modulators such as ulipristal acetete that has provided the gynecologist with a novel option for medical management of uterine fibroids. Ulipristal acetate is presently licensed in Europe for use in women with symptomatic fibroids up to 3 months prior to surgery and has demonstrated good clinical efficacy and safety for this indication. Future trials will define the long-term safety of this drug and its role in medical management of uterine fibroids.

A single baseline ultrasound assessment of fibroid presence and size is strongly predictive of future uterine procedure: 8-year follow-up of randomly sampled premenopausal women aged 35-49 years

STUDY QUESTION

How well can a single baseline ultrasound assessment of fibroid burden (presence or absence of fibroids and size of largest, if present) predict future probability of having a major uterine procedure?

SUMMARY ANSWER

During an 8-year follow-up period, the risk of having a major uterine procedure was 2% for those without fibroids and increased with fibroid size for those with fibroids, reaching 47% for those with fibroids ≥ 4 cm in diameter at baseline.

WHAT IS KNOWN ALREADY

Uterine fibroids are a leading indication for hysterectomy. However, when fibroids are found, there are few available data to help clinicians advise patients about disease progression.

STUDY DESIGN, SIZE, DURATION

Women who were 35-49 years old were randomly selected from the membership of a large urban health plan; 80% of those determined to be eligible were enrolled and screened with ultrasound for fibroids ≥ 0.5 cm in diameter. African-American and white premenopausal participants who responded to at least one follow-up interview (N = 964, 85% of those eligible) constituted the study cohort. During follow-up (5822 person-years), participants self-reported any major uterine procedure (67% hysterectomies). Life-table analyses and Cox regression (with censoring for menopause) were used to estimate the risk of having a uterine procedure for women with no fibroids, small (<2 cm in diameter), medium (2-3.9 cm), and large fibroids (≥ 4 cm). Differences between African-American and white women, importance of a clinical diagnosis of fibroids prior to study enrollment, and the impact of submucosal fibroids on risk were investigated.

PARTICIPANTS/MATERIALS, SETTING, METHODS

There was a greater loss to follow-up for African-Americans than whites (19 versus 11%). For those with follow-up data, 64% had fibroids at baseline, 33% of whom had had a prior diagnosis. Of those with fibroids, 27% had small fibroids (<2 cm in diameter), 46% had medium (largest fibroid 2-3.9 cm in diameter), and 27% had large fibroids (largest ≥ 4 cm in diameter). Twenty-one percent had at least one submucosal fibroid.

MAIN RESULTS AND THE ROLE OF CHANCE

Major uterine procedures were reported by 115 women during follow-up. The estimated risk of having a procedure in any given year of follow-up for those with fibroids compared with those without fibroids increased markedly with fibroid-size category (from 4-fold, confidence interval (CI) (1.4-11.1) for the small fibroids to 10-fold, CI (4.4-24.8) for the medium fibroids, to 27-fold, CI (11.5-65.2) for the large fibroids). This influence of fibroid size on risk did not differ between African-Americans and whites (P-value for interaction = 0.88). Once fibroid size at enrollment was accounted for, having a prior diagnosis at the time of ultrasound screening was not predictive of having a procedure. Exclusion of women with a submucosal fibroid had little influence on the results. The 8-year risk of a procedure based on lifetable analyses was 2% for women with no fibroids, 8, 23, and 47%, respectively, for women who had small, medium or large fibroids at enrollment. Given the strong association of fibroid size with subsequent risk of a procedure, these findings are unlikely to be due to chance.

LIMITATIONS, REASONS FOR CAUTION

Despite a large sample size, the number of women having procedures during follow-up was relatively small. Thus, covariates such as BMI, which were not important in our analyses, may have associations that were too small to detect with our sample size. Another limitation is that the medical procedures were self-reported. However, we attempted to retrieve medical records when participants agreed, and 77% of the total procedures reported were verified. Our findings are likely to be generalizable to other African-American and white premenopausal women in their late 30s and 40s, but other ethnic groups have not been studied.

WIDER IMPLICATIONS OF THE FINDINGS

Though further studies are needed to confirm and extend the results, our findings provide an initial estimate of disease progression that will be helpful to clinicians and their patients.

Proteoglycans in Leiomyoma and Normal Myometrium: Abundance, Steroid Hormone Control, and Implications for Pathophysiology

Uterine leiomyoma are a common benign pelvic tumors composed of modified smooth muscle cells and a large amount of extracellular matrix (ECM). The proteoglycan composition of the leiomyoma ECM is thought to affect pathophysiology of the disease. To test this hypothesis, we examined the abundance (by immunoblotting) and expression (by quantitative real-time polymerase chain reaction) of the proteoglycans biglycan, decorin, and versican in leiomyoma and normal myometrium and determined whether expression is affected by steroid hormones and menstrual phase. Leiomyoma and normal myometrium were collected from women (n = 17) undergoing hysterectomy or myomectomy. In vitro studies were performed on immortalized leiomyoma (UtLM) and normal myometrial (hTERT-HM) cells with and without exposure to estradiol and progesterone. In leiomyoma tissue, abundance of decorin messenger RNA (mRNA) and protein were 2.6-fold and 1.4-fold lower, respectively, compared with normal myometrium. Abundance of versican mRNA was not different between matched samples, whereas versican protein was increased 1.8-fold in leiomyoma compared with myometrium. Decorin mRNA was 2.4-fold lower in secretory phase leiomyoma compared with proliferative phase tissue. In UtLM cells, progesterone decreased the abundance of decorin mRNA by 1.3-fold. Lower decorin expression in leiomyoma compared with myometrium may contribute to disease growth and progression. As decorin inhibits the activity of specific growth factors, its reduced level in the leiomyoma cell microenvironment may promote cell proliferation and ECM deposition. Our data suggest that decorin expression in leiomyoma is inhibited by progesterone, which may be a mechanism by which the ovarian steroids affect leiomyoma growth and disease progression.

Predicting the results of uterine artery embolization: correlation between initial intramural fibroid volume and percentage volume decrease

Introduction and objective

Uterine artery embolization (UAE) is a minimally invasive treatment option for symptomatic fibroids. Long-term follow-up studies have shown that at five-year follow-up after UAE, up to 30% of patients required a hysterectomy. Therefore, it seems of utmost importance to identify patients, who are unlikely to benefit from UAE. It has been postulated that the percentage volume reduction of fibroids may predict long-term UAE outcome. The results of available studies are equivocal, therefore it seemed of interest to investigate the correlation between the preinterventional intramural fibroid volume and imaging outcome of UAE in premenopausal patients.

Material and methods

Uterine artery embolization was performed in 65 premenopausal patients with symptomatic, intramural fibroids. Dominant fibroid volume was assessed using an integrated VOCAL (Virtual Organ Computer-aided AnaLysis) imaging program at baseline and 3 months after UAE. The percentage reduction of fibroid volume was calculated. The association between preinterventional fibroid volumes and percentage volume reductions was determined with the Spearman rank correlation test.

Results

Before UAE, the median dominant fibroid volume was 101 cm³ (range 23.6-610). At three-month follow-up the median dominant leiomyoma volume decreased to 50.4 cm³ (range 6.9-193.9). Median percentage reduction of fibroid volume three months after UAE was calculated at 50.1% (range 2.7-93.5). The Spearman correlation test between the preinterventional dominant fibroid volume and percentage volume reduction showed a statistically significant, positive correlation (R = 0.33; p = 0.006).

Conclusions

The percentage volume reduction of intramural leiomyomas after UAE seems to be more pronounced in the case of larger tumors.

Uterine leiomyoma research

Uterine leiomyoma is the most common type of benign tumor in women of reproductive age. This disease is rare before menarche, and its incidence decreases after menopause. Uterine leiomyoma is known to be related to hormonal changes, but the precise underlying mechanism has yet to be determined. Although it is a benign disease, the most common form of management involves surgical intervention. Uterine leiomyoma is also related to infertility and obstetric complications. Here, we present a review of the literature regarding uterine leiomyoma and discuss management of this disease.

Contemporary management of uterine fibroids: focus on emerging medical treatments

OBJECTIVE

This review provides an overview of therapeutic options, with a specific focus on the emerging role of medical options for UF management.

RESEARCH DESIGN AND METHODS

PubMed, Google Scholar, and Cochrane Systematic Reviews were searched for articles published between 1980 and 2013. Relevant articles were identified using the following terms: 'uterine fibroids', 'leiomyoma', 'heavy menstrual bleeding', and 'menorrhagia'. The reference lists of articles identified were also searched for other relevant publications.

RESULTS

Because of the largely benign nature of UFs, the most conservative options that minimize morbidity/risk and optimize outcomes should be considered. Watchful waiting, or no immediate intervention combined with regular follow-up, is an appropriate option for the majority of UF patients who experience no symptoms. For women with symptomatic UFs, the optimal treatment should restore quality of life through rapid relief of UF signs and symptoms, reduce tumor size for a sustained period, and maintain or improve fertility. Invasive surgical treatments, such as hysterectomy, have historically been the mainstay of UF treatment. Less invasive surgical and interventional techniques, such as myomectomy, uterine artery embolization, endometrial ablation, and myolysis provide alternatives to hysterectomy. Until recently, medical management of UFs was characterized by short-term treatments and therapies that provided symptomatic control. In addition to controlling abnormal uterine bleeding, newer medical therapies, including the recently Health-Canada-approved ulipristal acetate, act directly to shrink the tumor. Although no agent is currently approved for such use, emerging evidence suggests the potential for long-term medical management of UFs.

CONCLUSIONS

The advent of novel medical therapies may diminish the long-held reliance on more invasive surgical UF treatment options.

Role of nuclear progesterone receptor isoforms in uterine pathophysiology

BACKGROUND

Progesterone is a key hormonal regulator of the female reproductive system. It plays a major role to prepare the uterus for implantation and in the establishment and maintenance of pregnancy. Actions of progesterone on the uterine tissues (endometrium, myometrium and cervix) are mediated by the combined effects of two progesterone receptor (PR) isoforms, designated PR-A and PR-B. Both receptors function primarily as ligand-activated transcription factors. Progesterone action on the uterine tissues is qualitatively and quantitatively determined by the relative levels and transcriptional activities of PR-A and PR-B. The transcriptional activity of the PR isoforms is affected by specific transcriptional coregulators and by PR post-translational modifications that affect gene promoter targeting. In this context, appropriate temporal and cell-specific expression and function of PR-A and PR-B are critical for normal uterine function.

METHODS

Relevant studies describing the role of PRs in uterine physiology and pathology (endometriosis, uterine leiomyoma, endometrial cancer, cervical cancer and recurrent pregnancy loss) were comprehensively searched using PubMed, Cochrane Library, Web of Science, and Google Scholar and critically reviewed.

RESULTS

Progesterone, acting through PR-A and PR-B, regulates the development and function of the endometrium and induces changes in cells essential for implantation and the establishment and maintenance of pregnancy. During pregnancy, progesterone via the PRs promotes myometrial relaxation and cervical closure. Withdrawal of PR-mediated progesterone signaling triggers menstruation and parturition. PR-mediated progesterone signaling is anti-mitogenic in endometrial epithelial cells, and as such, mitigates the tropic effects of estrogen on eutopic normal endometrium, and on ectopic implants in endometriosis. Similarly, ligand-activated PRs function as tumor suppressors in endometrial cancer cells through inhibition of key cellular signaling pathways required for growth. In contrast, progesterone via PR activation appears to increase leiomyoma growth. The exact role of PRs in cervical cancer is unclear. PRs regulate implantation and therefore aberrant PR function may be implicated in recurrent pregnancy loss (RPL). PRs likely regulate key immunogenic factors involved in RPL. However, the exact role of PRs in the pathophysiology of RPL and the use of progesterone for therapeutic benefit remains uncertain.

CONCLUSIONS

PRs are key mediators of progesterone action in uterine tissues and are essential for normal uterine function. Aberrant PR function (due to abnormal expression and/or function) is a major cause of uterine pathophysiology. Further investigation of the underlying mechanisms of PR isoform action in the uterus is required, as this knowledge will afford the opportunity to create progestin/PR-based therapeutics to treat various uterine pathologies.

Ovarian steroids, stem cells and uterine leiomyoma: therapeutic implications

BACKGROUND

Uterine leiomyoma is the most common benign tumor in women and is thought to arise from the clonal expansion of a single myometrial smooth muscle cell transformed by a cellular insult. Leiomyomas cause a variety of symptoms, including abnormal uterine bleeding, pelvic pain, bladder or bowel dysfunction, and recurrent pregnancy loss, and are the most common indication for hysterectomy in the USA. A slow rate of cell proliferation, combined with the production of copious amounts of extracellular matrix, accounts for tumor expansion. A common salient feature of leiomyomas is their responsiveness to steroid hormones, thus providing an opportunity for intervention.

METHODS

A comprehensive search of PUBMED was conducted to identify peer-reviewed literature published since 1980 pertinent to the roles of steroid hormones and somatic stem cells in leiomyoma, including literature on therapeutics that target steroid hormone action in leiomyoma. Reviewed articles were restricted to English language only. Studies in both animals and humans were reviewed for the manuscript.

RESULTS

Estrogen stimulates the growth of leiomyomas, which are exposed to this hormone not only through ovarian steroidogenesis, but also through local conversion of androgens by aromatase within the tumors themselves. The primary action of estrogen, together with its receptor estrogen receptor α (ERα), is likely mediated via induction of progesterone receptor (PR) expression, thereby allowing leiomyoma responsiveness to progesterone. Progesterone has been shown to stimulate the growth of leiomyoma through a set of key genes that regulate both apoptosis and proliferation. Given these findings, aromatase inhibitors and antiprogestins have been developed for the treatment of leiomyoma, but neither treatment results in complete regression of leiomyoma, and tumors recur after treatment is stopped. Recently, distinct cell populations were discovered in leiomyomas; a small population showed stem-progenitor cell properties, and was found to be essential for ovarian steroid-dependent growth of leiomyomas. Interestingly, these stem-progenitor cells were deficient in ERα and PR and instead relied on the strikingly higher levels of these receptors in surrounding differentiated cells to mediate estrogen and progesterone action via paracrine signaling.

CONCLUSIONS

It has been well established that estrogen and progesterone are involved in the proliferation and maintenance of uterine leiomyoma, and the majority of medical treatments currently available for leiomyoma work by inhibiting steroid hormone production or action. A pitfall of these therapeutics is that they decrease leiomyoma size, but do not completely eradicate them, and tumors tend to regrow once treatment is stopped. The recent discovery of stem cells and their paracrine interactions with more differentiated cell populations within leiomyoma has the potential to provide the missing link between developing therapeutics that temper leiomyoma growth and those that eradicate them.

Hyperplasia and fibrosis in mice with conditional loss of the TSC2 tumor suppressor in Müllerian duct mesenchyme-derived myometria

Uterine leiomyomata are the most common tumors found in the female reproductive tract. Despite the high prevalence and associated morbidities of these benign tumors, little is known about the molecular basis of uterine leiomyoma development and progression. Loss of the Tuberous Sclerosis 2 (TSC2) tumor suppressor has been proposed as a mechanism important for the etiology of uterine leiomyomata based on the Eker rat model. However, conflicting evidence showing increased TSC2 expression has been reported in human uterine leiomyomata, suggesting that TSC2 might not be involved in the pathogenesis of this disorder. We have produced mice with conditional deletion of the Tsc2 gene in the myometria to determine whether loss of TSC2 leads to leiomyoma development in murine uteri. Myometrial hyperplasia and increased collagen deposition was observed in Tsc2(cKO) mice compared with control mice, but no leiomyomata were detected by post-natal week 24. Increased signaling activity of mammalian target of rapamycin complex 1, which is normally repressed by TSC2, was also detected in the myometria of Tsc2(cKO) mice. Treatment of the mutant mice with rapamycin significantly inhibited myometrial expansion, but treatment with the progesterone receptor modulator, mifepristone, did not. The ovaries of the Tsc2(cKO) mice appeared normal, but half the mice were infertile and most of the other half became infertile after a single litter, which was likely due to oviductal blockage. Our study shows that although TSC2 loss alone does not lead to leiomyoma development, it does lead to myometrial hyperplasia and fibrosis.

Ulipristal acetate modulates the expression and functions of activin a in leiomyoma cells

Uterine leiomyoma is the most common benign gynecological tumor in women of reproductive age and represents the single most common indication for hysterectomy. A development of new treatments is necessary for a medical management, and in this direction, several hormonal drugs are under investigation. Ulipristal acetate (UPA; a selective progesterone receptor modulator) is considered as one of the most promising because progesterone has a critical role in development and growth of uterine leiomyoma. The effect of steroids is partly mediated by growth factors like activin A which increases extracellular matrix expression contributing to the growth of leiomyoma. The present study aimed to test whether UPA acts on leiomyoma cells affecting expression and functions of activin A system. Cultured myometrial and leiomyoma cells were treated with UPA, and messenger RNA (mRNA) expression levels of activin A (inhibin βA [INHBA] subunits), its binding proteins (follistatin [FST] and FST-related gene), and its receptors (activin receptor-like kinase 4 [ALK4], activin receptor type [ActR] II, and ActRIIB) were evaluated. The effect of UPA on activin A modulation of fibronectin and vascular endothelial growth factor A (VEGF-A) mRNA expression in cultured myometrial and leiomyoma cells was also studied. Ulipristal acetate decreased INHBA, FST, ActRIIB, and Alk4 mRNA expressions in leiomyoma cultured cells. In addition, UPA was able to block the activin A-induced increase in fibronectin or VEGF-A mRNA expression in myometrial and in leiomyoma cultured cells. The present data show that UPA inhibits activin A expression and functions in leiomyoma cells, and this may represent a possible mechanism of action of the drug on uterine leiomyoma.

Selective progesterone receptor modulators: an update

INTRODUCTION

Several selective progesterone receptor modulators (SPRMs) show promise in several areas of medicine and this work has been summarized by us in 2008.

AREAS COVERED

Since the publication of our reviews, several developments have taken place in the field of reproductive medicine. The first is emergency contraception (EC). Two SPRMs are clinically utilized today: mifepristone (MFP) and ulipristal acetate (UPA). MFP is available for EC in up to 120 h following unprotected intercourse. A dose of 10 mg is significantly more effective than levonorgestrel (LNG). In a metanalysis of the use of UPA versus LNG up to 72 h after unprotected intercourse, failure rates of 1.4 versus 2.2% were reported. The second is contraception. A daily dose of 2 mg MFP can block ovulation and several MFP regimens are being tested, including a vaginal ring releasing MFP. The third is the preoperative administration in women harboring leiomyomas, where clinical testing of several SPRM has shown that they can decrease uterine leiomyomas' size and substantially reduce uterine bleeding. SPRM can induce unusual, specific endometrial appearances. Many believe that these changes should not cause concern, but the issue remains controversial.

EXPERT OPINION

SPRMs are very effective in EC and for the preoperative treatment of uterine leiomyomas.