The effects of letrozole and melatonin on surgically induced endometriosis in a rat model: a preliminary study

Exploring melatonin's multifaceted role in female reproductive health: From follicular development to lactation and its therapeutic potential in obstetric syndromes

BACKGROUND

Melatonin is mainly secreted by the pineal gland during darkness and regulates biological rhythms through its receptors in the suprachiasmatic nucleus of the hypothalamus. In addition, it also plays a role in the reproductive system by affecting the function of the hypothalamic-pituitary-gonadal axis, and by acting as a free radical scavenger thus contributing to the maintenance of the optimal physiological state of the gonads. Besides, melatonin can freely cross the placenta to influence fetal development. However, there is still a lack of overall understanding of the role of melatonin in the reproductive cycle of female mammals.

AIM OF REVIEW

Here we focus the role of melatonin in female reproduction from follicular development to delivery as well as the relationship between melatonin and lactation. We further summarize the potential role of melatonin in the treatment of preeclampsia, polycystic ovary syndrome, endometriosis, and ovarian aging.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Understanding the physiological role of melatonin in female reproductive processes will contribute to the advancement of human fertility and reproductive medicine research.

Efficacy of colchicine and melatonin in the treatment of rat endometriosis model: An animal study

OBJECTIVE

This study investigates the therapeutic effects of colchicine and melatonin on endometriotic implants in an experimentally created endometriosis model in rats.

STUDY DESIGN

Forty-four adult female Wistar albino rats weighing between 260 and 300 g, 8 weeks old, were selected for the study. The unilateral uterine horn of rats with a bicornuate uterus was excised for 1 cm, washed with sterile saline, incised longitudinally, and the endometrium was exposed. A 0.5*0.5 cm endometrial tissue sample taken with a scalpel was implanted with suturing (4/0 Vicryl) to the abdominal wall. Forty-four rats were divided into four groups. Group 1 was randomized as the endometriosis group (control), Group 2 as endometriosis + colchicine treatment, Group 3 as endometriosis + melatonin treatment, and Group 4 as the endometriosis + melatonin + colchicine treatment group. The colchicine (Sigma Chemical Co., St Louis, Missouri) group was administered orally at a dose of 0.1 mg/kg, and the Melatonin group orally at a dose of melatonin (20 mg/kg per day). Treatment continued daily for 30 days.

RESULTS

In the post-treatment focal diameter measurements, the endometrial focal diameter in the colchicine and colchicine + melatonin group was significantly lower than the control group (p=0.026). Bcl-2 levels of the colchicine group were lower than the control group and the melatonin group (p=0.021).

CONCLUSION

Colchicine and melatonin reduce adhesion to the peritoneal surface in ectopic endometrial cells. It also acts by increasing apoptosis and decreasing cell survival.

Oxidative Imbalance in Endometriosis-Related Infertility-The Therapeutic Role of Antioxidants

Endometriosis in half of affected women is closely related to problems with fertility. Endometriosis-associated infertility is caused by a wide range of abnormalities affecting the female reproductive tract, from oocyte quality impairment to disturbances in the eutopic endometrium or mechanical abnormalities resulting from disease progression. Since supportive antioxidant therapies, in addition to surgical treatment or assisted reproductive techniques (ARTs), have overall been proven to be effective tools in endometriosis management, the objective of our review was to analyze the role of antioxidant substances, including vitamins, micronutrients, N-acetylcysteine (NAC), curcumin, melatonin, and resveratrol, in endometriosis-related infertility. Most of these substances have been proven to alleviate the systemic oxidant predominance, which has been expressed through decreased oxidative stress (OS) markers and enhanced antioxidative defense. In addition, we demonstrated that the predominant effect of the aforementioned substances is the inhibition of the development of endometriotic lesions as well as the suppression of pro-inflammatory molecules. Although we can undoubtedly conclude that antioxidants are beneficial in fertility support, further studies explaining the detailed pathways of their action are needed.

Melatonin: Current evidence on protective and therapeutic roles in gynecological diseases

Melatonin, a potent antioxidant and free radical scavenger, has been demonstrated to be effective in gynecological conditions and female reproductive cancers. This review consolidates the accumulating evidence on melatonin's multifaceted protective effects in different pathological contexts. In gynecological conditions such as endometriosis, polycystic ovary syndrome (PCOS), and uterine leiomyoma, melatonin has shown promising effects in reducing oxidative stress, inflammation, and hormonal imbalances. It inhibits adhesion molecules' production, and potentially mitigates leukocyte adherence and inflammatory responses. Melatonin's regulatory effects on hormone production and insulin sensitivity in PCOS individuals make it a promising candidate for improving oocyte quality and menstrual irregularities. Moreover, melatonin exhibits significant antitumor effects by modulating various signaling pathways, promoting apoptosis, and suppressing metastasis in breast cancers and gynecological cancers, including ovarian, endometrial, and cervical cancers. Furthermore, melatonin's protective effects are suggested to be mediated by interactions with its receptors, estrogen receptors and other nuclear receptors. The regulation of clock-related genes and circadian clock systems may also contribute to its inhibitory effects on cancer cell growth. However, more comprehensive research is warranted to fully elucidate the underlying molecular mechanisms and establish melatonin as a potential therapeutic agent for these conditions.

Ferroptosis and oxidative stress in endometriosis: A systematic review of the literature

BACKGROUND

Endometriosis (EMT) a common gynecological condition in women, an inflammatory disease characterized by the presence of endometrial tissue on organs and tissues in the pelvis, and is mainly associated with chronic pelvic pain and infertility. As the etiology has not been fully elucidated, current treatment is limited to surgery, hormones and painkillers, with more side effects and difficulty in achieving long-term relief. Oxidative stress manifests itself as an overproduction of reactive oxygen species, which has an integral impact in the pathology of female reproductive disorders. In this review, we evaluate the mechanisms of iron overload-induced oxidative stress and ferroptosis in EMT and their pathophysiological implications.

METHODS

Because the etiology has not been fully elucidated, current treatments are limited to surgery, hormones, and painkillers, which have many side effects and are difficult to achieve long-term relief.

RESULTS

We interpreted that antioxidants as well as ferroptosis inducers show promising results in the treatment of EMT, but their application in this population needs to be further investigated.

CONCLUSION

In combination with the interpretation of previous studies, it was shown that iron overload is present in the peritoneal fluid, endometriotic lesions, peritoneum and macrophages in the abdominal cavity. However, the programmed cellular ferroptosis associated with iron overload is resisted by endometriotic foci, which is critical to the pathophysiology of EMT with local iron overload and inflammation.

Recent insights explaining susceptibility to endometriosis-From genetics to environment

Endometriosis is a disease with a heterogeneous pathogenesis, explained by multiple theories, and also with a polymorphic presentation. The purpose of this literature review is to systematize the genetic, inflammatory, and environmental factors related to the pathophysiology of endometriosis. Current evidence suggests that endometriosis is a complex inherited genetic condition, in which the genes that determine susceptibility to the disease interact with the environment to develop different phenotypes. Genetic variants associated with risk of endometriosis have been identified in several genome-wide association studies, in addition to a group of genes related to the pathophysiology of endometriosis, namely the estrogen, progesterone and androgen receptors and the cytochrome P450 gene, as well as the p53 gene. The role of inflammation is controversial; however, it is an essential process, both in the initiation and perpetuation of the disease, in and outside the pelvis. Alterations in reactive oxygen species pathways that consequently determine oxidative stress are typical in the inflammatory environment of endometriosis. The role of environmental factors is a relatively new and broad-spectrum topic, with inconsistent evidence. Multiple factors have been studied such as endocrine-disrupting chemicals, metals, intrauterine exposure to diethylstilbesterol and lifestyle risk factors. In conclusion, endometriosis remains a mysterious condition, with multifactorial factors involved in its pathophysiology. The progress that has been made in the genetic predisposition to endometriosis may allow the establishment of new therapeutic targets. On the other hand, understanding the role of the environment in this disease may allow preventive intervention, minimizing its incidence and/or severity. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology Reproductive System Diseases > Environmental Factors Reproductive System Diseases > Genetics/Genomics/Epigenetics.

Adjuvant use of melatonin for pain management in endometriosis-associated pelvic pain-A randomized double-blinded, placebo-controlled trial

Considering the pharmacological treatment options for endometriosis-associated pain are confined to hormonal therapy and analgesics, we studied the analgesic effect of 20 mg melatonin as an adjuvant therapy in women with endometriosis-associated pain. This randomized double-blinded, placebo-controlled trial was conducted at the Research Center for Womens' Health at Södersjukhuset, a university hospital in Stockholm, Sweden. Forty women from 18 to 50 years of age with endometriosis and severe dysmenorrhea with or without chronic pelvic pain were given 20 mg Melatonin or placebo orally daily for two consecutive menstrual cycles or months. The level of pain was recorded daily on the 11-point numeric rating scale, a difference of 1.3 units was considered clinically significant. Clincaltrials.gov nr NCT03782740. Sixteen participants completed the study in the placebo group and 18 in the melatonin group. The difference in endometriosis-associated pain between the groups showed to be non-significant statistically as well as clinically, 2.9 (SD 1.9) in the melatonin group and 3.3 (SD 2.0) in the placebo group, p = 0.45. This randomized, double-blinded, placebo-controlled trial could not show that 20 mg of melatonin given orally at bedtime had better analgesic effect on endometriosis-associated pain compared with placebo. No adverse effects were observed.

Therapeutic effects of melatonin on endometriosis, targeting molecular pathways: Current knowledge and future perspective

Endometriosis, the very serious disease in women creates a huge financial burden worldwide, which is comparable to diabetes mellitus. In addition to the typical pelvic pain, endometriosis is related to low life quality and decreased work efficiency; clinical consequences include mood complaints, metabolic impairments, inflammation, immunologic problems, and elevated malignancy risks. Several risk factors are correlated with endometriosis including elevated oxidative and nitrosative stress, long-lasting inflammation, raised immune tolerance, as well as autoimmunity. Melatonin is a natural molecule present throughout both the plant and animal kingdoms. It has numerous functions as an antioxidant and anti-inflammatory agent. Due to the anti-proliferative, antioxidant, anti-inflammatory, and anti-invasive features of melatonin, it performances as a beneficial agent to limit endometriosis; this involves several pathways including antiestrogenic, antioxidant, anti-inflammatory, and anti-apoptosis effects, as well as reducing the growth of E2-induced endometriotic tissue. Moreover, melatonin can favor sleep quality and decrease the unwanted signs in the patients. However, most of the data on melatonin accured from experimental works and additional clinical trials are needed. This review summarizes what is currently known regarding the influence of melatonin on endometriosis. AVAILABILITY OF DATA AND MATERIAL: Not applicable.

Emerging hallmarks of endometriosis metabolism: A promising target for the treatment of endometriosis

Endometriosis, characterized by ectopic endometrium growth in the extrauterine environment, is one of the most notable diseases of the female reproductive system. Worldwide, endometriosis affects nearly 10 % of women in their reproductive years and causes a significant decline in quality of life. Despite extensive investigations of endometriosis over the past years, the mechanisms of endometriosis pathogenesis remain unclear. In recent years, metabolic factors have increasingly been considered factors in endometriosis. There is compelling evidence regarding the progress of endometriosis in the context of severe metabolic dysfunction. Hence, the curative strategies and ongoing attempts to conquer endometriosis might start with metabolic pathways. This review focuses on metabolic mechanisms and summarizes current research progress. These findings provide valuable information for the non-intrusive diagnosis of the disease and may contribute to the understanding of the pathogenesis of endometriosis.

Coping with Oxidative Stress in Reproductive Pathophysiology and Assisted Reproduction: Melatonin as an Emerging Therapeutical Tool

Infertility is an increasing global public health concern with socio-psychological implications for affected couples. Remarkable advances in reproductive medicine have led to successful treatments such as assisted reproductive techniques (ART). However, the search for new therapeutic tools to improve ART success rates has become a research hotspot. In the last few years, pineal indolamine melatonin has been investigated for its powerful antioxidant properties and its role in reproductive physiology. It is considered a promising therapeutical agent to counteract the detrimental effects associated with oxidative stress in fertility treatments. The aim of the present narrative review was to summarize the current state of the art on the importance of melatonin in reproductive physiology and to provide a critical evaluation of the data available encompassing basic, translational and clinical studies on its potential use in ART to improve fertility success rates.

Melatonin in Endometriosis: Mechanistic Understanding and Clinical Insight

Endometriosis is defined as the development of endometrial glands and stroma outside the uterine cavity. Pathophysiology of this disease includes abnormal hormone profiles, cell survival, migration, invasion, angiogenesis, oxidative stress, immunology, and inflammation. Melatonin is a neuroendocrine hormone that is synthesized and released primarily at night from the mammalian pineal gland. Increasing evidence has revealed that melatonin can be synthesized and secreted from multiple extra-pineal tissues where it regulates immune response, inflammation, and angiogenesis locally. Melatonin receptors are expressed in the uterus, and the therapeutic effects of melatonin on endometriosis and other reproductive disorders have been reported. In this review, key information related to the metabolism of melatonin and its biological effects is summarized. Furthermore, the latest in vitro and in vivo findings are highlighted to evaluate the pleiotropic functions of melatonin, as well as to summarize its physiological and pathological effects and treatment potential in endometriosis. Moreover, the pharmacological and therapeutic benefits derived from the administration of exogenous melatonin on reproductive system-related disease are discussed to support the potential of melatonin supplements toward the development of endometriosis. More clinical trials are needed to confirm its therapeutic effects and safety.

Letrozole promotes the expression of integrin αvβ3 and HOXA10 in endometrium of endometriosis

Endometriosis is a common estrogen-dependent chronic inflammatory disease that leads to infertility in women of reproductive age. Perhaps infertility reflects the reduced expression of integrin αvβ3 and HOXA10 in endometriosis. Previous studies have shown that administration of letrozole, a non-steroidal aromatase inhibitor for cancer treatment, increased the clinical pregnancy rate in women with endometriosis, but the mechanisms remain to be determined. In this communication, a rat model of endometriosis was established. Animals were treated with letrozole at 2ug/kg of body weight, intragastric administration for 15 consecutive days. Letrozole increased the expression of αvβ3 and HOXA10 in the endometriosis model and endometrial receptivity.Abbreviations: WOI: window of implantation; RGD: Arg-Gly-Asp; HOX: homeobox; E2: estradiol; SPF: specific pathogen-free.

Involvement of endometrial IGF-1R/IGF-1/Bcl-2 pathways in experimental polycystic ovary syndrome: Identification of the regulatory effect of melatonin

The involvement of endometrial IGF-1R/IGF-1/Bcl-2 pathways and the potential regulatory effects of exogenously administrated melatonin on this expression is investigated in the experimental PCOS model in the present study. Thirty-two 6-8 week old Sprague Dawley rats were divided into four groups: the Sham Control Group (1% CMC/day by oral gavage [o.g.]); the Melatonin Group (2 mg/kg/day melatonin by subcutaneous administration [s.c.]); the Experimental PCOS Group (1 mg/kg/day Letrozole by o.g.); and the Experimental PCOS + Melatonin Group (1 mg/kg/day Letrozole by o.g. and 2 mg/kg/day melatonin by s.c. administration). Vaginal smear samples were taken from the 14th day to the end of the experiment for colpocytological measurements. At the end of the 21 day experimental period, uterine tissues were taken; Hematoxylin-Eosin histochemical, IGF-1R/IGF-1/Bcl-2, PCNA immuno-histochemical stainings and western blot analyses were performed for related antibodies. All of the data was supported statistically. The epithelium of endometrium lost its single-layer structure in some parts, separation was observed between the epithelium and the basal membrane junction, intracellular edema was found in the uterine glands by the polycystic ovary-induction. Also this induction increased the expression of IGF-1R/IGF-1, Bcl-2, and PCNA proteins. Morphological degenerations returned to its normal appearance generally by the melatonin administrations and melatonin also regulated the increased expression of endometrial IGF-1R/IGF-1/Bcl-2 and PCNA pathways. It is concluded that additional studies are needed, using melatonin as a supporting agent may be appropriate in cases of PCOS.

Can Endometriosis-Related Oxidative Stress Pave the Way for New Treatment Targets?

Endometriosis is a disease of reproductive age characterized by chronic pelvic pain and infertility. Its pathogenesis is complex and still partially unexplained. However, there is increasing evidence of the role of chronic inflammation, immune system dysregulation, and oxidative stress in its development and progression. The latter appears to be involved in multiple aspects of the disease. Indeed, disease progression sustained by a hyperproliferative phenotype can be related to reactive oxygen species (ROS) imbalance, as numerous experiments using drugs to counteract hyperproliferation have shown in recent years. Chronic pelvic pain is also associated with cell function dysregulation favoring chronic inflammation and oxidative stress, specifically involving macrophages and mast cell activation. Moreover, there is increasing evidence of a role for ROS and impaired mitochondrial function not only as deleterious effectors of the ovarian reserve in patients with endometriomas but also in terms of oocyte quality and, hence, embryo development impairment. Targeting oxidative stress looks to be a promising strategy to both curb endometriotic lesion progression and alleviate endometriosis-associated symptoms of chronic pain and infertility. More investigations are nevertheless needed to develop effective therapeutic strategies for clinical application.

Melatonin activity and receptor expression in endometrial tissue and endometriosis

STUDY QUESTION

Are melatonin receptors (melatonin receptor 1A (MR1A) and melatonin receptor 1B (MR1B)) expressed in human endometrium and endometriotic tissue, and does melatonin affect endometrial cell proliferation?

SUMMARY ANSWER

Melatonin receptors are expressed in human eutopic endometrium, endometriomas and peritoneal lesions, although to different extents, and melatonin treatment attenuated estradiol-induced endometrial epithelial cell proliferation in culture.

WHAT IS KNOWN ALREADY

Melatonin decreased endometriotic lesion volume in a rat model of endometriosis. Melatonin treatment reduced pain scores in and analgesic use by women with endometriosis.

STUDY DESIGN, SIZE, DURATION

Basic science study using human endometrial tissue and an endometrial epithelial cell line.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Measurement of melatonin receptor expression (mRNA and protein) in women with surgically confirmed endometriosis (endometrioma (n = 20) or peritoneal lesion (n = 11) alone) and women without surgical evidence of endometriosis (control, n = 15). Collection of endometrial and endometriotic tissue samples, gynecologic history and demographic information. Quantification of estradiol (1.0 nM) and melatonin (0.1 nM-1.0 μM) ± estradiol-induced endometrial epithelial cell proliferation in cultures of endometrial epithelial cells (CRL-1671) following 24 and 48 hours of culture.

MAIN RESULTS AND THE ROLE OF CHANCE

MR1A and MR1B were localized by immunohistochemistry in glandular epithelial cells of endometrial biopsies from women with and without endometriosis. Both receptors were expressed in eutopic and ectopic endometrial tissue. mRNA expression of MR1A and MR1B was significantly greater in peritoneal lesions than in either endometriomas or eutopic endometrium. However, protein expression of MR1A was decreased in peritoneal lesions compared to control eutopic endometrium, whereas MR1B expression did not differ between the groups. Melatonin (0.1 nM-1.0 μM) treatment inhibited estradiol (1.0 nM)-induced endometrial epithelial cell proliferation at 48 hours but not 24 hours of culture.

LIMITATIONS, REASONS FOR CAUTION

Beneficial effects of melatonin seen in culture have yet to be comprehensively evaluated in women with endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Our data suggest that melatonin may be useful as an adjunct to current endometriosis treatments.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Canadian Institutes of Health Research (grant MOP142230 to W.G.F.). A.A.M. is supported by a resident research grant through the Physicians Services Incorporated Foundation. The authors have no conflicts of interest.

Effect of melatonin for the management of endometriosis: A protocol of systematic review and meta-analysis

BACKGROUND

This study aims to explore the effect of melatonin for the management of endometriosis.

METHODS

We will search electronic databases (Cochrane Library, MEDLINE, EMBASE, CINAHL, Web of Science, Scopus, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure) from their inceptions to the February 29, 2020 without language and publication time limitations. The study identification, study quality assessment, and data extraction will be undertaken by two separate researchers. We will also appraise evidence quality of main outcomes by Grading of Recommendations Assessment Development and Evaluation, and statistical analysis performance by RevMan 5.3 Software.

RESULTS

This study will summarize up-to-date clinical evidence to investigate the effect of melatonin for the management of endometriosis.

CONCLUSION

This study may provide helpful evidence of melatonin for the management of endometriosis.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202040093.

Melatonin Promotes Uterine and Placental Health: Potential Molecular Mechanisms

The development of the endometrium is a cyclic event tightly regulated by hormones and growth factors to coordinate the menstrual cycle while promoting a suitable microenvironment for embryo implantation during the “receptivity window”. Many women experience uterine failures that hamper the success of conception, such as endometrium thickness, endometriosis, luteal phase defects, endometrial polyps, adenomyosis, viral infection, and even endometrial cancer; most of these disturbances involve changes in endocrine components or cell damage. The emerging evidence has proven that circadian rhythm deregulation followed by low circulating melatonin is associated with low implantation rates and difficulties to maintain pregnancy. Given that melatonin is a circadian-regulating hormone also involved in the maintenance of uterine homeostasis through regulation of numerous pathways associated with uterine receptivity and gestation, the success of female reproduction may be dependent on the levels and activity of uterine and placental melatonin. Based on the fact that irregular production of maternal and placental melatonin is related to recurrent spontaneous abortion and maternal/fetal disturbances, melatonin replacement may offer an excellent opportunity to restore normal physiological function of the affected tissues. By alleviating oxidative damage in the placenta, melatonin favors nutrient transfer and improves vascular dynamics at the uterine–placental interface. This review focuses on the main in vivo and in vitro functions of melatonin on uterine physiological processes, such as decidualization and implantation, and also on the feto-maternal tissues, and reviews how exogenous melatonin functions from a mechanistic standpoint to preserve the organ health. New insights on the potential signaling pathways whereby melatonin resists preeclampsia and endometriosis are further emphasized in this review.

Effects of silymarin, cabergoline and letrozole on rat model of endometriosis

OBJECTIVE

Silymarin as an herbal drug has potent antioxidant effects that could make it a good choice for endometriosis therapy. The aim of the current study was to determine the effects of silymarin as an herbal drug on induced endometrial lesion in rat model of endometriosis.

MATERIALS AND METHODS

A total of 32 mature, female Sprague-Dawley rats were allocated into 4 experimental groups. The duration of study was about 6 months. Endometriosis implants were surgically prepared and autografted into 32 rats. Three weeks after endometriosis induction, animals were randomly allocated into four groups: Group 1 received cabergoline (CAB group); Group 2 received letrozole (LET group); Group 3 received silymarin (SIL group) and Group 4 received no medication (CONT group). Experimental groups were treated for 3 weeks and then were sacrificed for volume and histopathological evaluation of implants and biochemical assessment. Serum and peritoneal levels of vascular endothelial growth factor (VEGF), total antioxidant activity (TAC) and tumor necrosis (TNF)-α were measured.

RESULTS

Mean volume of the implants decreased significantly in silymarin (p < 0.001), letrozole (p < 0.001) and cabergoline (p < 0.001) groups compared to the control. Histopathologic score was significantly lower in silymarin (p: 0.039), letrozole (p: 0.017) and cabergoline (p < 0.001) groups compared to the control. Those receiving silymarin had significantly higher serum TAC compared to control after 21 days of therapy (p < 0.001).

CONCLUSION

Silymarin, Letrozole, and Cabergoline administration resulted in decreased size and histopathologic grade of the induced endometrial lesions in a rat model. Silymarin appears to be a virtual novel therapeutic agent for treatment of endometriosis.

The beneficial effects of nerolidol and hesperidin on surgically induced endometriosis in a rat model. Gynecol Endocrinol 2018;34:975-980. [PMID: 29734842 DOI: 10.1080/09513590.2018.1469611]

The objective of this article is to analyze the effects of nerolidol and hesperidin treatment on surgically induced endometriosis in a rat model. Endometriosis was induced in 24 healthy adult female Wistar albino rats via homologous uterine horn transplantation. Three operations were performed on each rat. After the second operation, the rats were randomized into control, nerolidol, and hesperidin treatment groups, and medications were administered for 2 weeks. The effects of the drugs on the endometriotic foci were evaluated after the third operation. Compared with the endometriosis control group, the average volume of the lesions was significantly lower in rats treated with hesperidin and nerolidol. Malondialdehyde levels were significantly reduced in the nerolidol-treated group, and glutathione levels and superoxide dismutase activity were significantly elevated in the endometriotic foci of both the hesperidin- and nerolidol-treated groups compared with the endometriosis group. Hesperidin and nerolidol treatment also improved histological parameters, such as hemorrhage, vascular congestion, necrosis, and inflammatory cell infiltration in the endometriotic foci. The results of this study demonstrated that treatment with the potent antioxidants nerolidol and hesperidin caused a significant regression of surgically induced endometriotic foci in rats.

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.

Melatonin inhibits 17β-estradiol-induced migration, invasion and epithelial-mesenchymal transition in normal and endometriotic endometrial epithelial cells

BACKGROUND

Melatonin is a potential therapeutic agent for endometriosis, but its molecular mechanism is unclear. Here, we investigated the effect of melatonin on the epithelial-mesenchymal transition (EMT) in endometriotic endometrial epithelial cells and explored the pathway that might be involved.

METHODS

This hospital-based study included 60 women of reproductive age using the endometrium for immunohistochemistry, 6 women of reproductive age undergoing bilateral tubal ligation and 6 patients with endometriosis for isolation of endometrial epithelial cells or subsequent analysis, respectively. We examined the expression of Notch1/Numb signaling and EMT markers by immunohistochemistry analysis and western blot analysis, the invasion and migration of endometrial epithelial cells by transwell assays, and the cell proliferation by CCK8 assays.

RESULTS

Compared with normal endometrium, the endometriotic eutopic endometrium showed increased expression of Notch1, Slug, Snail, and N-cadherin, and decreased expression of E-cadherin and Numb. Melatonin or Notch inhibition by specific inhibitor blocked 17β-estradiol-induced cell proliferation, invasion, migration and EMT-related markers in both normal and endometriotic epithelial cells.

CONCLUSIONS

Our data suggest that aberrant expression of Notch1/Numb signaling and the EMT is present in endometriotic endometrium. Melatonin may block 17β-estradiol-induced migration, invasion and EMT in normal and endometriotic epithelial cells by upregulating Numb expression and decreasing the activity of the Notch signaling pathway.

Role of erythropoietin and its receptor in the development of endometriosis in rats

Objective:

Besides its hematopoietic function, erythropoietin (EPO) may protect tissues from degenerative disorders. As such, EPO and its receptors were revealed in nonhematopoietic cells, including stromal and endometrial epithelial cells. However, the role of EPO in endometrial disorders is still unknown. Here, we aimed to examine the role of EPO and its receptor activation in the development of endometriosis in rats.

Material and Methods:

Animals were treated with EPO, darbepoietin (the synthetic form of EPO) or EPO’s receptor activator, methoxy polyethylene glycol-epoetin beta (MIRCERA), after development of endometriosis. Endometriosis was induced by estrogen-administration following surgical attachment of endometrial surface on the inner abdominal wall. Treatments were started 3 weeks after induction of endometriosis and continued for the following 3 weeks. For the analysis of recurrence of endometriosis, additional analyses were conducted 3 weeks after cessation of treatments.

Results:

As compared with vehicle-treated animals, lesion size was reduced significantly and recurrence of endometriosis was not observed in all treatment groups. Histopathologic examination revealed that EPO and darbepoietin were more effective than MIRCERA- and vehicle-treated animals.

Conclusion:

Here we provide evidence that EPO is a promising candidate for the treatment of endometriosis. Our histopathologic results in particular indicate that EPO is more effective than its receptor activator MIRCERA in the development endometriosis.

Pleiotropic roles of melatonin in endometriosis, recurrent spontaneous abortion, and polycystic ovary syndrome

Melatonin is a neurohormone synthesized from the aromatic amino acid tryptophan mainly by the pineal gland of mammals. Melatonin acts as a broad-spectrum antioxidant, powerful free radical scavenger, anti-inflammatory agent, anticarcinogenic factor, sleep inducer and regulator of the circadian rhythm, and potential immunoregulator. Melatonin and reproductive system are interrelated under both physiological and pathological conditions. Oxidative stress, inflammation, and immune dysregulation are associated with the pathogenesis of the female reproductive system which causes endometriosis (EMS), recurrent spontaneous abortion (RSA), and polycystic ovary syndrome (PCOS). Accumulating studies have indicated that melatonin plays pleiotropic and essential roles in these obstetrical and gynecological disorders and would be a candidate therapeutic drug to regulate inflammation and immune function and protect special cells or organs. Here, we systematically review the pleiotropic roles of melatonin in EMS, RSA, and PCOS to explore its pathological implications and treatment potential.

Effects of cisplatin and letrozole on surgically induced endometriosis and comparison of the two medications in a rat model

This study was to investigate the effects of cisplatin (CDDP) and letrozole on surgically induced endometriosis and comparison of the two drugs in a rat model. Endometriosis was surgically induced by autologous transplantation of endometrial pieces. Thirty model rats were divided into three groups, randomly. Group 1 (n=10) served as control and received no medication. Group 2 (n=10) received 0.2mg/kg/day of oral letrozole. Group 3 (n=10) received 35mg/m(2) CDDP via peritoneal perfusion every four days. All the rats were treated for 24days. The growth and histologic score of the implants were evaluated. The proliferation- and angiogenesis-associated proteins were assessed using immunohistochemistry and western blotting. The serum sex hormones were assayed using ELISA. After the medication, the growth and histologic score of the implants were significantly lower in the 2 and 3 groups than in the control group. The protein expressions of vascular endothelial growth factor (VEGF), aromatase P450 (P450arom), transforming growth factor-beta (TGF-β), and matrix metalloproteinase (MMP)-2, were significantly lower in groups 2 and 3 than in the control group. Further, the P450arom level was lower in the letrozole group than in the CDDP group. The TGF-β and MMP-2 levels were lower in the CDDP group than in the letrozole group. Serum T level was significantly higher in the letrozole group, and serum E2 level was lower in the letrozole group. In conclusion, cisplatin and letrozole caused similar regression of the implants in the endometriosis model rats. But their effects on the proliferation- and angiogenesis-associated protein expressions and the serum sex hormone levels were different. Cisplatin and letrozole might cause the effects in the endometriotic foci through different mechanism.

The Impact of Endometriosis across the Lifespan of Women: Foreseeable Research and Therapeutic Prospects

In addition to estrogen dependence, endometriosis is characterized by chronic pelvic inflammation. The impact of the chronic pelvic inflammatory state on other organ systems and women's health is unclear. Endometriosis associated chronic inflammation and potential adverse health effects across the lifespan render it imperative for renewed research vigor into the identification of novel biomarkers of disease and therapeutic options. Herein we propose a number of opportunities for research and development of new therapeutics to address the unmet needs in the treatment of endometriosis per se and its ancillary risks for other diseases in women across the lifespan.

Human chorionic gonadotropin improves endometriosis through downregulation of leptin expression in rats

OBJECTIVE

To investigate whether and how human chorionic gonadotropin (HCG) treatment ameliorates endometriosis in an endometriotic rat model.

METHODS

Twenty-four endometriosis rats were established and were randomly divided into four groups, and then the rats were treated with 19.4, 25.8, and 51.6 IU/100 g weight/day of HCG, respectively. The control group was treated with 0.9% NaCl. After 15 days (3 estrous cycles), the ectopic lesion volume and the expression of leptin protein in eutopic and ectopic endometrium were investigated.

RESULTS

After HCG treatment, the volumes of endometriotic lesions were significantly smaller than those before treatment. During endometriosis development, the expression of leptin protein in eutopic and ectopic endometrium was remarkably increased. HCG administration reversed leptin upregulation in endometriotic tissues.

CONCLUSION

HCG therapy appears to be an effective treatment for endometriosis in rats through down-regulation of leptin expression in eutopic and ectopic endometrium.

Combination use of ferulic acid, ligustrazine and tetrahydropalmatine inhibits the growth of ectopic endometrial tissue: a multi-target therapy for endometriosis rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ferulic acid (FA), ligustrazine (LZ) and tetrahydropalmatine (THP) are separately isolated from Chinese Angelica, Szechwan Lovage Rhizome and Rhizoma in the Jiawei-Foshou-San formula, a popular traditional Chinese medicine for irregular menses. It has been reported that the combination use of FA+LZ+THP has similar effect on endometriosis, but the underlying mechanisms are unclear. This study was to investigate the combination effects and mechanisms of FA+LZ+THP on endometriosis rats.

MATERIALS AND METHODS

Fifty endometriosis rats were intragastricly treated with FA+LZ+THP for 4 wk. The volume of ectopic endometrial tissue was measured to evaluate the effects. Then the changes in hypothalamic-pituitary-ovarian axis and ERE pathway were indicated by the levels of E2, GnRH, FSH and LH, and the expressions of ER, HSP90 and COX-2, respectively. In addition, peritoneal macrophages of each rat were cultured in vitro and treated with (FA+LZ+THP)-medicated serum for 24h. The proliferation and phagocytosis abilities, the levels of IL-1β and TNF-α, and the expression of IκBα were then measured for the changes of peritoneal macrophage activities.

RESULTS

Combination use of FA+LZ+THP diminished the volume of the ectopic endometrial tissues (P<0.05 or P<0.01). It also decreased the E2 level, suppressed the expression of GnRH, FSH and LH, and decreased the protein expression of ER, HSP90 and COX-2 (all P<0.05 or P<0.01). The phagocytosis ability of peritoneal macrophage was enhanced by (FA+LZ+THP)-medicated serum (P<0.05) with no change of proliferation (P>0.05). Moreover, IL-1β and TNF-α were downregulated (both P<0.05 or P<0.01) and IκBα was upregulated by the (FA+LZ+THP)-medicated serum (P<0.01).

CONCLUSIONS

The combination use of FA, LZ and THP could inhibit the growth of ectopic endometrial tissue in endometriosis rats. It might be related to the down-regulation of hypothalamic-pituitary-ovarian axis, the amelioration in ERE pathway and the improvement of peritoneal macrophage activities.

Advances in the Pathogenesis of Adhesion Development: The Role of Oxidative Stress

Over the past several years, there has been increasing recognition that pathogenesis of adhesion development includes significant contributions of hypoxia induced at the site of surgery, the resulting oxidative stress, and the subsequent free radical production. Mitochondrial dysfunction generated by surgically induced tissue hypoxia and inflammation can lead to the production of reactive oxygen and nitrogen species as well as antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase which when optimal have the potential to abrogate mitochondrial dysfunction and oxidative stress, preventing the cascade of events leading to the development of adhesions in injured peritoneum. There is a significant cross talk between the several processes leading to whether or not adhesions would eventually develop. Several of these processes present avenues for the development of measures that can help in abrogating adhesion formation or reformation after intraabdominal surgery.

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.

Melatonin treatment results in regression of endometriotic lesions in an ooferectomized rat endometriosis model

OBJECTIVE

We aimed to determine the effects of melatonin treatment on endometrial implants in an oopherectomized rat endometriosis model.

MATERIAL AND METHODS

This study is a prospective, randomised, controlled experimental study. It was carried out at the Experimental Research Center of Yeditepe University (YUDETAM). Twenty-two, female, non-pregnant, nulligravid Spraque-Dawley albino rats were included in our study. Endometriosis was surgically induced in oopherectomized rats. Rats were randomised into two groups: control group and melatonin group. In the melatonin group, rats were treated with melatonin (20 mg/kg/day) for two weeks. After the operations were performed to assess the regression of the endometriotic lesions, melatonin treatment was stopped. At the end of the sixth week necropsies were performed to assess the rate of recurrence. The volume and histopathological scores of endometriotic foci were examined.

RESULTS

Volumes of the endometriotic lesions significantly decreased in the melatonin group. Also, when the melatonin group was analysed within itself, endometriotic lesion volumes decreased and histopathological scores increased significantly.

CONCLUSION

Melatonin causes regression of the endometriotic lesions in rats and improvement in their histopathological scores.

Efficacy of melatonin in the treatment of endometriosis: a phase II, randomized, double-blind, placebo-controlled trial

Endometriosis-associated chronic pelvic pain (EACPP) presents with an intense inflammatory reaction. Melatonin has emerged as an important analgesic, antioxidant, and antiinflammatory agent. This trial investigates the effects of melatonin compared with a placebo on EACPP, brain-derived neurotrophic factor (BDNF) level, and sleep quality. Forty females, aged 18 to 45 years, were randomized into the placebo (n = 20) or melatonin (10 mg) (n = 20) treatment groups for a period of 8 weeks. There was a significant interaction (time vs group) regarding the main outcomes of the pain scores as indexed by the visual analogue scale on daily pain, dysmenorrhea, dysuria, and dyschezia (analysis of variance, P < 0.01 for all analyses). Post hoc analysis showed that compared with placebo, the treatment reduced daily pain scores by 39.80% (95% confidence interval [CI] 12.88-43.01%) and dysmenorrhea by 38.01% (95% CI 15.96-49.15%). Melatonin improved sleep quality, reduced the risk of using an analgesic by 80%, and reduced BNDF levels independently of its effect on pain. This study provides additional evidence regarding the analgesic effects of melatonin on EACPP and melatonin's ability to improve sleep quality. Additionally, the study revealed that melatonin modulates the secretion of BDNF and pain through distinct mechanisms.

The effects of metformin and letrozole on endometrium and ovary in a rat model

OBJECTIVE

The effects of metformin and letrozole on endometrium and ovarian reserve were studied in a rat model.

METHODS

Forty female Wistar albino mature rats at 8 weeks, weighing 180-260 g, were used for the study. These rats were randomly divided into four groups. Control group, eight rats, was given no medication by oral gavage. The rats in low-dose metformin group, 10 rats, were given 100 mg/kg/day of oral metformin. The rats in high-dose metformin group, 10 rats, were given 200 mg/kg/day of oral metformin. The rats in letrozole, 10 rats, were given 0.1 mg/kg/day of oral letrozole.

RESULTS

There was statistically significant difference in the endometrial thickness between the treatment groups and control group. The primordial follicle count was comparable in all treatment groups compared with control. Finally, there was no significant difference in total follicle count between the treatment groups and control.

CONCLUSIONS

This study showed that both metformin and letrozole had similar effects on endometrium and ovary in the rat model. Additionally, metformin had a little effect on endometrium than letrozole. Although metformin and letrozole might have tendency to enhance the total follicle count in the rat model, they had comparable effects on ovarian follicles and did not change the ovarian reserve compared with control.