Dienogest inhibits nerve growth factor expression induced by tumor necrosis factor-α or interleukin-1β

The Sphingosine 1-Phosphate Axis: an Emerging Therapeutic Opportunity for Endometriosis

Endometriosis is a common condition in women of reproductive age, but its current interventions are unsatisfactory. Recent research discovered a dysregulation of the sphingosine 1-phosphate (S1P) signaling pathway in endometriosis and showed a positive outcome by targeting it. The S1P axis participates in a series of fundamental pathophysiological processes. This narrative review is trying to expound the reported and putative (due to limited reports in this area for now) interactions between the S1P axis and endometriosis in those pathophysiological processes, to provide some perspectives for future research. In short, S1P signaling pathway is highly activated in the endometriotic lesion. The S1P concentration has a surge in the endometriotic cyst fluid and the peritoneal fluid, with the downstream dysregulation of its receptors. The S1P axis plays an essential role in the migration and activation of the immune cells, fibrosis, angiogenesis, pain-related hyperalgesia, and innervation. S1P receptor (S1PR) modulators showed an impressive therapeutic effect by targeting the different S1P receptors in the endometriosis model, and many other conditions resemble endometriosis. And several of them already got approval for clinical application in many diseases, which means a drug repurposing direction and a rapid clinical translation for endometriosis treatments.

Single-cell transcriptomic analysis of endometriosis

Endometriosis is a common condition in women that causes chronic pain and infertility and is associated with an elevated risk of ovarian cancer. We profiled transcriptomes of >370,000 individual cells from endometriomas (n = 8), endometriosis (n = 28), eutopic endometrium (n = 10), unaffected ovary (n = 4) and endometriosis-free peritoneum (n = 4), generating a cellular atlas of endometrial-type epithelial cells, stromal cells and microenvironmental cell populations across tissue sites. Cellular and molecular signatures of endometrial-type epithelium and stroma differed across tissue types, suggesting a role for cellular restructuring and transcriptional reprogramming in the disease. Epithelium, stroma and proximal mesothelial cells of endometriomas showed dysregulation of pro-inflammatory pathways and upregulation of complement proteins. Somatic ARID1A mutation in epithelial cells was associated with upregulation of pro-angiogenic and pro-lymphangiogenic factors and remodeling of the endothelial cell compartment, with enrichment of lymphatic endothelial cells. Finally, signatures of ciliated epithelial cells were enriched in ovarian cancers, reinforcing epidemiologic associations between these two diseases.

Dienogest May Reduce Estradiol- and Inflammatory Cytokine-Induced Cell Viability and Proliferation and Inhibit the Pathogenesis of Endometriosis: A Cell Culture- and Mouse Model-Based Study

Dienogest (DNG) is a therapeutic medication used in endometriosis treatment. Limited data are available regarding its mechanism of action on endometrial cells. Using in vivo and in vitro models, we investigated whether DNG treatment causes significant biological changes in human endometrial stromal cells (ESCs). The markers related to the pathogenesis of endometriosis in ESCs were evaluated using estradiol, tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and IL-32, administered alone or in combination with DNG. Implanted endometrial tissues were compared between C57BL/6 mice that did or did not receive DNG treatment by using size measurements and immunohistochemistry. A significant decrease in cell viability, protein kinase B (AKT) phosphorylation, and the expression of p21-activated kinase 4 and vascular endothelial growth factor were observed in ESCs treated with estradiol plus DNG. Cell viability, AKT phosphorylation, and proliferating cell nuclear antigen (PCNA) expression also decreased significantly after TNF-α plus DNG treatment. Treatment with IL-1β or IL-32 plus DNG significantly decreased cell viability or PCNA expression, respectively. The size of the implanted endometrial tissue significantly decreased in mice treated with DNG, accompanied by decreased PCNA expression. Thus, DNG may reduce cell viability and proliferation induced by estradiol, TNF-α, IL-1β, and IL-32, and inhibit the endometriosis pathogenesis by decreasing PCNA expression.

Immunopathogenesis of endometriosis: An overview of the role of innate and adaptive immune cells and their mediators

BACKGROUND

Endometriosis is a chronic inflammatory disease associated with the growth and proliferation of endometrial-like tissues outside the uterus. Although the exact etiology and mechanism of the pathogenesis of the disease have not been fully elucidated, the immune system cells and the mediators produced by them can be named as effective factors in the onset and progression of the disease.

AIMS

We aim to attempt to review studies on the role of the immune system in endometriosis to better understand the pathogenesis of endometriosis.

CONTENT

Abundant production of inflammatory mediators by neutrophils and macrophages and reduced cytotoxicity of defined cells promote endometriosis at the early stages of the disease. Following an increase in the inflammation of the environment, the body takes compensatory mechanisms to reduce inflammation and establish homeostasis. For this purpose, the body produces remodeling and anti-inflammatory factors leading to slow conversion of the inflammatory environment into a non-inflammatory environment with proliferative and immunosuppressive properties. Environmental conditions induce M2 macrophages, TH2 cells, and Tregs differentiation, promoting disease progression by producing angiogenic and immunosuppressive factors. However, the exact molecular mechanism involved in changing inflammatory to non-inflammatory conditions is not yet fully understood.

IMPLICATIONS

Due to the common characteristics of endometriotic cells and cancer cells, most potential treatment options for endometriosis have been suggested due to the results of these methods in the treatment of cancer. In this pathway, immune system cells and soluble mediators can be used as targets.

Efficacy of dienogest vs combined oral contraceptive on pain associated with endometriosis: Randomized clinical trial

OBJECTIVE

To compare the efficacy of dienogest with the combined oral contraceptive pill (COC) Yasmin for the control of endometriosis-associated pelvic pain.

STUDY DESIGN

Seventy women with endometriosis-associated chronic pelvic pain, dysmenorrhoea or both for >6 months were randomized to either dienogest (Visanne) 2 mg/day or monophasic COC (Yasmin, 0.03 mg ethinyl estradiol and 3 mg drospirenone) for 24 weeks. The primary efficacy variable was change in non-cyclic pelvic pain and dysmenorrhoea from baseline to end of treatment, assessed using a visual analogue scale (VAS). The secondary efficacy variable was change in the Biberoglu and Behrman (B&B) scale scores for chronic pelvic pain, dysmenorrhoea and dyspareunia. Health-related quality of life (HRQoL) was evaluated using the Endometriosis Health Profile-30 (EHP-30) questionnaire at baseline and 24 weeks. Safety variables included incidence of side-effects, bleeding pattern and treatment tolerability.

RESULTS

Both treatments improved the mean VAS score for endometriosis-associated pelvic pain significantly: mean difference 6.0 [95% confidence interval (CI) 4.9-7.1; p < 0.0001] in the dienogest group and 4.54 (95% CI 3.1-5.9; p < 0.0001) in the COC group; the difference between them was not significant (p = 0.111). Similarly, both dienogest and COC improved HRQoL in various core and modular segments of the EHP-30 questionnaire with comparable requirements for supplemental pain medication (p = 0.782 and 0.258 at 12 and 24 weeks, respectively), and redistribution of the B&B severity profile for chronic pelvic pain (p = 0.052 and 0.526 at 12 and 24 weeks, respectively), dysmenorrhoea (p = 0.521 and 1 at 12 and 24 weeks, respectively) and dyspareunia (p = 0.376 and 0.835, respectively). Nevertheless, dienogest was associated with fewer side-effects, and hence had a better safety and tolerability profile than COC.

CONCLUSIONS

Dienogest (2 mg/day) is comparable to the COC Yasmin for the relief of endometriosis-associated pelvic pain and improvement in HRQoL.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov under number NCT04256200; date of registration 15/1/2020 (registered retrospectively).

Systematic review and Meta-analysis of efficacy and safety of dienogest in treatment of endometriosis

BACKGROUND

The quality of life of women with endometriosis is substantially adversely affected by the pelvic pain caused by this disease. However, the choice of medication for endometriosis remains controversial, and no drug has been clearly proven to be superior to others.

AIM

To assess the efficacy and safety of dienogest, a synthetic progestin, in the treatment of women with painful symptoms of endometriosis.

METHODS

PubMed, EMBASE, the Cochrane Library, and the Web of Science databases were searched from their inceptions to January 21, 2020 for randomized controlled trials (RCTs) that compared dienogest with other popular prescription drugs for the treatment of endometriosis. Two reviewers extracted the data. Mean difference (MD) values and risk ratios (RRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Ultimately, seven RCTs with a total of 1493 participants met the requirements for this review. Dienogest was found to more effective than placebo in alleviating endometriosis-related pain (MD = -32.93, 95%CI: -44.63 to -21.23), but led to a more significant decline in plasma estradiol concentrations than placebo (MD = -44.7, 95%CI: -62.24 to -24.69). Dienogest was superior to gonadotropin-releasing hormone analogues (GnRH-a) in relieving pain (MD = -2.41, 95%CI: -3.58 to -1.24). Moreover, compared with dienogest, GnRH-a were significantly more likely to lead to the loss of bone mineral density (MD = 2.77, 95%CI: 0.16 to 5.37) and were significantly associated with a higher incidence of headaches (RR = 0.68, 95%CI: 0.52 to 0.91) and hot flushes (RR = 0.43, 95%CI: 0.18 to 1.02).

CONCLUSION

This meta-analysis demonstrated that dienogest may be a better pain-relief treatment for endometriosis patients, due to its high efficacy and tolerability.

Dienogest versus continuous oral levonorgestrel/EE in patients with endometriosis: what's the best choice?

OBJECTIVE

Combined oral contraceptives (COC) and progestogens are widely used for the treatment of endometriosis. The objective of the study is to compare the efficacy of dienogest 2 mg vs continuous oral levonorgestrel/EE (levonorgestrel 0.1 mg/ethinyl estradiol 0.02 mg) on ovarian endometriomas, deep infiltrating endometriosis (DIE), chronic pelvic pain (CPP), dyspareunia, analgesic use, quality of life (QoL), compliance and side effects.

METHODS

Prospective cohort study. Two cohorts of patients with endometriosis, 50 taking dienogest (group A) and 50 taking continuous levonorgestrel/EE (group B), were evaluated at the beginning of therapy (t0), after 3 (t3) and 6 months (t6). Size of endometriomas, DIE, QoL, pain symptoms, and side effects were assessed.

RESULTS

Dienogest was significantly effective on CPP (p = .002), dyspareunia (p = .021) ovarian endometriomas (p = .015) and DIE lesions reduction (p = .014). Levonorgestrel/EE was significantly effective on dyspareunia (p = .023). Analgesics consumption significantly decreased in both groups (p < .001). Both treatments significantly improved the QoL. Over 6 months a significant improvement was found, more frequently in patients taking dienogest. The only side effect that both groups complained about was vaginal bleeding, present in the first 3 months of treatment (p < .001).

CONCLUSIONS

Both treatments are effective and safe for patients with endometriosis. Patients compliance and side effects are similar in both groups, however, there was a significantly higher reduction in endometriotic lesions, pain symptoms, and improvement of the QoL in women taking dienogest than in women taking continuous COC.

Autonomic nervous system and inflammation interaction in endometriosis-associated pain

Endometriosis is a chronic inflammatory disease. Pain is the most common symptom in endometriosis. Endometriosis-associated pain is caused by inflammation, and is related to aberrant innervation. Although the specific mechanism between endometriosis-associated pain and the interaction of aberrant innervation and inflammation remains unclear, many studies have confirmed certain correlations between them. In addition, we found that some chronic inflammatory autoimmune diseases (AIDs) such as inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) share similar characteristics: the changes in dysregulation of inflammatory factors as well as the function and innervation of the autonomic nervous system (ANS). The mechanisms underlying the interaction between the ANS and inflammation have provided new advances among these disorders. Therefore, the purpose of this review is to compare the changes in inflammation and ANS in endometriosis, IBD, and RA; and to explore the role and possible mechanism of sympathetic and parasympathetic nerves in endometriosis-associated inflammation by referring to IBD and RA studies to provide some reference for further endometriosis research and treatment.

Oxytocinergic regulation in pathogenesis of pelvic pain caused by adenomyosis

OBJECTIVE

The aim of the study was to expand the understanding of pathogenesis of adenomyosis-associated pelvic pain.

MATERIAL AND METHODS

We studied 30 (n = 30) biopsy samples obtained after hysterectomy in women with diffuse adenomyosis of grade II-III, accompanied by severe pain syndrome, who did not receive hormonal therapy. The morphologic comparison group comprised 30 (n = 30) biopsy samples obtained from women with adenomyosis, without pain syndrome, operated on for abnormal uterine bleeding, who also did not receive hormone therapy.

RESULTS

The total density of immunological OTR labeling in the adenomyotic lesion foci was 73.7 ± 1.8%, and in the morphological control group it was 35.2 ± 1.4% (p <0.05), which indicates a significant effect of oxytocin as a ureterotonic peptide. Processes of local neurogenesis and growth of nerve fibers was established due to an increase in the expression of the nervous system growth factor NGF in the myometrium stroma, in comparison with biopsy samples of morphological control.

Conclusion: Pelvic pain pathogenesis in women with diffuse adenomyosis compared with the painless form of the disease is an increase in the activity of ureterotonic factors of OTR oxytocin. Compared to the painless form of adenomyosis, the myometrial innervation apparatus of patients with pelvic pain is characterized by a significantly higher expression of nerve growth factor.

Fractalkine/CX3CR1 Contributes to Endometriosis-Induced Neuropathic Pain and Mechanical Hypersensitivity in Rats

Pain is the most severe and common symptom of endometriosis. Its underlying pathogenetic mechanism is poorly understood. Nerve sensitization is a particular research challenge, due to the limitations of general endometriosis models and sampling nerve tissue from patients. The chemokine fractalkine (FKN) has been demonstrated to play a key role in various forms of neuropathic pain, while its role in endometriotic pain is unknown. Our study was designed to explore the function of FKN in the development and maintenance of peripheral hyperalgesia and central sensitization in endometriosis using a novel endometriosis animal model developed in our laboratory. After modeling, behavioral tests were carried out and the optimal time for molecular changes was obtained. We extracted ectopic tissues and L4-6 spinal cords to detect peripheral and central roles for FKN, respectively. To assess morphologic characteristics of endometriosis-like lesions-as well as expression and location of FKN/CX3CR1-we performed H&E staining, immunostaining, and western blotting analyses. Furthermore, inhibition of FKN expression in the spinal cord was achieved by intrathecal administration of an FKN-neutralizing antibody to demonstrate its function. Our results showed that implanted autologous uterine tissue around the sciatic nerve induced endometriosis-like lesions and produced mechanical hyperalgesia and allodynia. FKN was highly expressed on macrophages, whereas its receptor CX3CR1 was overexpressed in the myelin sheath of sciatic nerve fibers. Overexpressed FKN was also observed in neurons. CX3CR1/pp38-MAPK was upregulated in activated microglia in the spinal dorsal horn. Intrathecal administration of FKN-neutralizing antibody not only reversed the established mechanical hyperalgesia and allodynia, but also inhibited the expression of CX3CR1/pp38-MAPK in activated microglia, which was essential for the persistence of central sensitization. We concluded that the FKN/CX3CR1 signaling pathway might be one of the mechanisms of peripheral hyperalgesia in endometriosis, which requires further studies. Spinal FKN is important for the development and maintenance of central sensitization in endometriosis, and it may further serve as a novel therapeutic target to relieve persistent pain associated with endometriosis.

Expression of Nerve Injury-Induced Protein1 (Ninj1) in Endometriosis

OBJECTIVE

The aim of this study was to clarify the expression of Ninj1 in endometriosis and adenomyosis lesions, and its inductive factor in human endometriotic stromal cells (ESCs).

BACKGROUND

Nerve injury-induced protein 1 (Ninj1) is a molecule originally identified in dorsal root ganglion neurons and Schwann cells after nerve injury and promotes neurite outgrowth. The aim of this study was to clarify the expression of Ninj1 in endometriosis and adenomyosis lesions, and its inductive factor in human endometriotic stromal cells (ESCs).

MATERIALS AND METHODS

Tissues were obtained with consent from patients diagnosed with ovarian endometrioma (n = 15 in total), peritoneal endometriosis (n = 5), adenomyosis (n = 5), and other gynecological disorders (n = 5, control) during surgery. Immunohistochemistry was conducted in order to detect Ninj1 protein expression in the lesion of endometriosis, adenomyosis, and eutopic endometrium. Nerve fibers in the ovarian endometrioma were detected by positive staining of PGP-9.5. To evaluate the effects of IL-1β on Ninj1 gene expression in endometriosis, ESCs isolated from ovarian endometrioma (n = 5) were treated with IL-1β (5 ng/mL) for 3 or 6 hours. Messenger RNA (mRNA) expression for Ninj1 was examined using quantitative RT-PCR.

RESULTS

The Ninj1 protein was expressed by ovarian endometrioma, peritoneal endometriotic, and adenomyotic tissue. Nerve fibers were found in the areas of positive staining for Ninj1 in ovarian endometrioma. IL-1β, an indicator of inflammation in endometriosis, significantly increased Ninj1 mRNA expression by ESC.

CONCLUSION

Our study demonstrates that Ninj1 is expressed in endometriosis and adenomyosis and is induced by the inflammatory stimuli. Given the neurogenetic property of Ninj1, our results imply that Ninj1, induced by inflammation in endometriosis lesion, may contribute to the pathogenesis of pain symptoms characteristic of endometriosis.

Aromatase as a target for treating endometriosis

Endometriosis is a common gynecological disease that causes various clinical symptoms, such as chronic pelvic pain, dysmenorrhea and infertility, seriously affecting women's health and their quality of life. The symptoms and endometriotic lesions are relieved, in many cases, after menopause, when estrogen levels are lowered. Therefore, endometriosis is considered to be estrogen-dependent. Aromatase, the enzyme responsible for the last step of estrogen biosynthesis converting testosterone and androgen to estrogen, was previously reported to be more abundant in endometriotic tissues than in the normal endometrium, leading to an increased local estrogen concentration. Therefore, aromatase is considered a key therapeutic target for regulating local estrogen biosynthesis in endometriosis. A more complete understanding of the mechanisms that modulate aromatase and its activity is required to develop novel estrogen-targeted therapies for endometriosis. In this review article, we outline the current understanding of the pathological processes involved in estrogen production in endometriosis and propose novel strategies to treat this disorder.

Genetic Variation at Chromosome 2q13 and Its Potential Influence on Endometriosis Susceptibility Through Effects on the IL-1 Family

Endometriosis is characterized by the growth of epithelial and stromal cells outside the uterine cavity. It has a complex etiology and affects ∼10% of reproductive age women. It is accompanied by a chronic inflammatory response with substantial evidence to indicate genetic susceptibility. The causal genes and their pathways leading to endometriosis, however, are still unknown. Recently, genomewide association studies on endometriosis identified 14 genomic risk loci in women of European and Japanese ancestry. It is becoming increasingly clear that these risk regions are intergenic and thus contribute to disease susceptibility through regulatory mechanisms, most likely mediated through regulation of genes within a restricted distance from the risk variants. One endometriosis risk locus has been detected at chromosome 2q13 within an inflammatory-rich region of gene transcripts and thus may play a role in the inflammation component of the disease. We carried out detailed analysis of the genomic region 250 kb on either side of sentinel SNP rs10167914 and identified 21 transcripts which contained 6 interleukin (IL)-1 family genes, 3 previously reported coding genes that have a relationship to inflammation, 4 novel coding, or pseudogenes, and 8 noncoding RNA transcripts. Through an extensive literature search, we examined the roles these genes and their resultant proteins play in endometriosis pathogenesis. The results suggest alteration in the expression the IL-1 family transcripts either alone or as a complex milieu could have a significant influence on endometriosis and should be prioritized for future study on the implications of inflammation on endometriotic lesions.

Local upregulation of transient receptor potential ankyrin 1 and transient receptor potential vanilloid 1 ion channels in rectosigmoid deep infiltrating endometriosis

Transient Receptor Potential Vanilloid 1 (TRPV1) and Transient Receptor Potential Ankyrin 1 (TRPA1) expressed mainly by primary sensory neurons function as major nociceptive integrators. They are also present on the rat endometrium in an oestrogen-regulated manner. TRPV1 is upregulated in peritoneal and ovarian endometriosis patients, but there is no information about TRPA1 and their pathophysiological significances. In this study, patients undergoing laparoscopic surgery were investigated: severe dysmenorrhoea due to rectosigmoid deep infiltrating endometriosis ( n = 15), uterine fibroid-induced moderate dysmenorrhoea ( n = 7) and tubal infertility with no pain ( n = 6). TRPA1 and TRPV1 mRNA and protein expressions were determined by quantitative polymerase chain reaction and semi-quantitative immunohistochemistry from the endometrium samples taken by curettage. Results were correlated with the clinical characteristics including pain intensity. TRPA1 and TRPV1 receptors were expressed in the healthy human endometrium at mRNA and protein levels. Sparse, scattered cytoplasmic TRPA1 and TRPV1 immunopositivities were found in the stroma and epithelial layers. We detected upregulated mRNA levels in deep infiltrating endometriosis lesions, and TRPV1 gene expression was also elevated in autocontrol endometrium of deep infiltrating endometriosis patients. Histological scoring revealed significant TRPA1 and TRPV1 difference between deep infiltrating endometriosis stroma and epithelium, and in deep infiltrating endometriosis epithelium compared to control samples. Besides, we measured elevated stromal TRPV1 immunopositivity in deep infiltrating endometriosis. Stromal TRPA1 and TRPV1 immunoreactivities strongly correlated with dysmenorrhoea severity, as well TRPV1 expression on ectopic epithelial cells and macrophages with dyspareunia. Epithelial TRPA1 and stromal TRPV1 immunopositivity also positively correlated with dyschezia severity. We provide the first evidence for the presence of non-neuronal TRPA1 receptor in the healthy human endometrium and confirm the expression of TRPV1 channels. Their upregulations in rectosigmoid deep infiltrating endometriosis lesions and correlations with pain intensity suggest potential roles in pathophysiological mechanisms of the disease.

Can Wound Exudate from Venous Leg Ulcers Measure Wound Pain Status?: A Pilot Study

We investigated the associations between the self-evaluated pain status and two pain biomarker candidates, nerve growth factor and S100A8/A9, in exudate from venous leg ulcer to finally develop an objective pain evaluation method. Patients with venous leg ulcer participated in this cross-sectional observational study conducted between April and October 2014 at two medical facilities. During routine wound care, each participant self-evaluated their pain status at each examination using the 10-point numerical rating scale (present pain intensity) and the short-form McGill Pain Questionnaire 2 (continuous pain, intermittent pain, neuropathic pain, affective descriptors, and total score). Venous leg ulcer exudate sample was collected after wound cleansing. The nerve growth factor and S100A8/A9 concentrations in the venous leg ulcer exudate were measured by enzyme-linked immunosorbent assay and standardized according to the wound area. The association between each pain status and the two standardized protein concentrations was evaluated using Spearman’s correlation coefficient. In 30 sample collected from 13 participants, the standardized nerve growth factor concentration was negatively correlated with continuous pain (ρ = -0.47, P = 0.01), intermittent pain (ρ = -0.48, P = 0.01), neuropathic pain (ρ = -0.51, P = 0.01), and total score (ρ = -0.46, P = 0.01). The standardized S100A8/A9 concentration was positively correlated with present pain intensity (ρ = 0.46, P = 0.03) and continuous pain (ρ = 0.48, P = 0.03). Thus, these two proteins may be useful for objective evaluation of wound pain in venous leg ulcer patients.

Does dienogest influence the inflammatory response of endometriotic cells? A systematic review

OBJECTIVE AND DESIGN

A systematic review of all literature was done to assess the ability of the progestin dienogest (DNG) to influence the inflammatory response of endometriotic cells.

MAIN OUTCOME MEASURES

In vitro and in vivo studies report an influence of DNG on the inflammatory response in eutopic or ectopic endometrial tissue (animal or human).

RESULTS

After strict inclusion criteria were satisfied, 15 studies were identified that reported a DNG influence on the inflammatory response in endometrial tissue. These studies identified a modulation of prostaglandin (PG) production and metabolism (PGE2, PGE2 synthase, cyclo-oxygenase-2 and microsomal PGE synthase-1), pro-inflammatory cytokine and chemokine production [interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-α, monocyte chemoattractant protein-1 and stromal cell-derived factor-1], growth factor biosynthesis (vascular endothelial growth factor and nerve growth factor) and signaling kinases, responsible for the control of inflammation. Evidence supports a progesterone receptor-mediated inhibition of the inflammatory response in PR-expressing epithelial cells. It also indicated that DNG inhibited the inflammatory response in stromal cells, however, whether this was via a PR-mediated mechanism is not clear.

CONCLUSIONS

DNG has a significant effect on the inflammatory microenvironment of endometriotic lesions that may contribute to its clinical efficacy. A better understanding of the specific anti-inflammatory activity of DNG and whether this contributes to its clinical efficacy can help develop treatments that focus on the inhibition of inflammation while minimizing hormonal modulation.

Dienogest reduces HSD17β1 expression and activity in endometriosis

Endometriosis is an estrogen-dependent disease. Abnormally biosynthesized estrogens in endometriotic tissues induce the growth of the lesion and worsen endometriosis-associated pelvic pain. Dienogest (DNG), a selective progesterone receptor agonist, is widely used to treat endometriosis and efficiently relieves the symptoms. However, its pharmacological action remains unknown. In this study, we elucidated the effect of DNG on enzymes involved in local estrogen metabolism in endometriosis. Surgically obtained specimens of 23 ovarian endometriomas (OE) and their homologous endometrium (EE), ten OE treated with DNG (OE w/D), and 19 normal endometria without endometriosis (NE) were analyzed. Spheroid cultures of stromal cells (SCs) were treated with DNG and progesterone. The expression of aromatase, 17β-hydroxysteroid dehydrogenase 1 (HSD17β1), HSD17β2, HSD17β7, HSD17β12, steroid sulfatase (STS), and estrogen sulfotransferase (EST) was evaluated by real-time quantitative PCR. The activity and protein level of HSD17β1 were measured with an enzyme assay using radiolabeled estrogens and immunohistochemistry respectively. OESCs showed increased expression of aromatase, HSD17β1, STS, and EST, along with decreased HSD17β2 expression, when compared with stromal cells from normal endometria without endometriosis (NESCs) (P<0.01) or stromal cells from homologous endometrium (EESCs) (P<0.01). In OESCs, DNG inhibited HSD17β1 expression and enzyme activity at 10(-7) M (P<0.01). Results of immunohistochemical analysis displayed reduced HSD17β1 staining intensity in OE w/D (P<0.05). In conclusion, DNG exerts comprehensive inhibition of abnormal estrogen production through inhibition of aromatase and HSD17β1, contributing to a therapeutic effect of DNG on endometriosis.

Dienogest, a synthetic progestin, down-regulates expression of CYP19A1 and inflammatory and neuroangiogenesis factors through progesterone receptor isoforms A and B in endometriotic cells

Dienogest (DNG) is a selective progesterone receptor (PR) agonist and oral administration of DNG is used for the treatment of endometriosis. DNG is considered to act on PR to down-regulate pathophysiological factors associated with endometriosis. PR exists as two major isoforms, PR-A and PR-B, and their physiological functions are mostly distinct. It was suggested that PR isoform expression patterns are altered in endometriosis, but it is unknown whether the pharmacological effects of DNG are exerted through PR-A, PR-B or both. In the present study, we investigated the pharmacological effects of DNG through these PR isoforms on the expression of CYP19A1 which encodes aromatase and inflammatory and neuroangiogenesis factors associated with the pain and progression of endometriosis. We used immortalized human endometriotic epithelial cell lines that specifically express PR-A or PR-B in a spheroid cell culture system, and treated them with DNG. We evaluated messenger RNA (mRNA) expression of CYP19A1, prostaglandin (PG)E2 synthase (cyclooxygenase (COX)-2 and microsomal PGE2 synthase (mPGES)-1), inflammatory cytokines (interleukin (IL)-6, IL-8, and monocyte chemoattractant protein (MCP)-1) and neuroangiogenesis factors (vascular endothelial growth factor (VEGF) and nerve growth factor (NGF)) using real-time polymerase chain reaction. In addition, PGE2 production was measured by enzyme immunoassay. We found that DNG down-regulated mRNA expression of CYP19A1, COX-2, mPGES-1, IL-6, IL-8, MCP-1, NGF and VEGF, and PGE2 production in human endometriotic epithelial cell lines that specifically express either PR-A or PR-B. These results demonstrate that DNG activates both PR-A and PR-B and down-regulates the expression of pathophysiological factors associated with pain and progression of endometriosis. Our results suggest that DNG exerts therapeutic efficacy against the pain and progression of endometriosis regardless of PR isoform expression patterns.

Inflammation and nerve fiber interaction in endometriotic pain

Endometriosis is an extremely prevalent estrogen-dependent condition characterized by the growth of ectopic endometrial tissue outside the uterine cavity, and is often presented with severe pain. Although the relationship between lesion and pain remains unclear, nerve fibers found in close proximity to endometriotic lesions may be related to pain. Also, women with endometriosis pain develop central sensitization. Endometriosis creates an inflammatory environment and recent research is beginning to elucidate the role of inflammation in stimulating peripheral nerve sensitization. In this review, we discuss endometriosis-associated inflammation, peripheral nerve fibers, and assess their potential mechanism of interaction. We propose that an interaction between lesions and nerve fibers, mediated by inflammation, may be important in endometriosis-associated pain.

Dienogest in women with persistent endometriosis-related pelvic pain during norethisterone acetate treatment

OBJECTIVE

To evaluate patient satisfaction at 6-months dienogest (DNG) treatment in women with symptomatic rectovaginal endometriosis who had pain persistence and were unsatisfied after 6-months of norethisterone acetate (NETA) therapy.

STUDY DESIGN

This 24-weeks pilot open-label prospective study enrolled 25 women. The main outcome was the degree of patient satisfaction measured by using a Likert scale. Secondary outcomes were to evaluate differences in endometriosis-related pain, quality of life, sexual function changes and volumetric nodules changes during DNG compared to NETA treatment.

RESULTS

Patient satisfaction improved at 3- and 6-months (p<0.001, respectively) treatment with DNG compared with baseline treatment with NETA. Six months DNG treatment decreased the intensity of all the endometriosis-associated pain (chronic pelvic pain, dyspareunia, dyschezia) compared to baseline (p<0.001 for all comparisons). Quality of life and quality of sexual life evaluated with the EHP-30 and FSFI, respectively, increased after 6 months treatment. The volume of the endometriotic nodules did not significantly change during treatment.

CONCLUSIONS

This study confirms the efficacy of DNG in treating symptomatic women with rectovaginal endometriosis even in a particular endometriotic subpopulation of NETA "resistant" patients. Further randomized clinical trials comparing these two progestins both in first than second line are warranted.

Estrogen receptor (ER) agonists differentially regulate neuroangiogenesis in peritoneal endometriosis via the repellent factor SLIT3

Endometriosis is an estrogen-dependent neurovascular disorder characterized by growth of endometrial tissue (lesions) outside the uterine cavity. Patients suffer chronic pelvic pain, and it has been proposed that co-recruitment of nerves/blood vessels (neuroangiogenesis) into the lesions is fundamental to the development of painful symptoms. We hypothesized that estrogen-dependent regulation of axonal guidance molecules of the SLIT/ROBO (Roundabout) family could play a role in neuroangiogenesis occurring in endometriosis lesions found on the peritoneal wall. In tissue samples from human patients and a mouse model of endometriosis, concentrations of mRNA encoded by SLIT3 were significantly higher in lesions than normal peritoneum. Estrogen regulation of SLIT3 was investigated using 17β-estradiol and selective agonists for each subtype of estrogen receptor (ER) (ERα agonist, 4,4',4″-(4-propyl-(1H)-pyrazole-1,3,5-tryl) trisphenol; ERβ agonist, 2,3-bis(4-hydroxy-phenyl)-propionitrile [DPN]). In mice, DPN (EC50 0.85) increased Slit3 mRNA concentrations compared with hormone-depleted and 17β-estradiol-treated (EC50 0.1) animals and decreased the density of nerves but not vessels in endometriosis lesions. SLIT3 mRNA concentrations were increased in DPN-treated human endometrial endothelial cells and in 4,4',4″-(4-propyl-(1H)-pyrazole-1,3,5-tryl) trisphenol-treated (EC50 200) rat dorsal root ganglia neurons. Functional assays (neurite outgrowth, network formation) revealed that SLIT3 promotes angiogenesis but decreases neurogenesis. In conclusion, these data suggest that estrogen-dependent expression of SLIT3 may play a key role in regulating nerve-vessel interactions within the complex microenvironment of endometriosis lesions.