Mechanism of pain generation for endometriosis-associated pelvic pain

Effects of osteopathic manipulative therapy on recurrent pelvic pain and dyspareunia in women after surgery for endometriosis: a retrospective study

BACKGROUND

Surgical removal of deep infiltrating endometriosis is frequently associated with improvement in symptoms. However, because of the complex pathogenesis of pain in endometriosis that includes central sensitization and myofascial dysfunction, symptoms can persist after surgery. The aim of the present observational study is to explore the effectiveness of osteopathic manipulative treatment (OMT) in reducing persistent pelvic pain and dyspareunia in a sample of symptomatic women surgically treated for endometriosis.

METHODS

Retrospective cohort analysis of 69 patients treated with OMT, for persistent myofascial pain, chronic pelvic pain (CPP) and dyspareunia after surgical eradication of endometriosis. Surgical, clinical and osteopathic reports were retrospectively analyzed in a chart review. Osteopathic interventions included myofascial release, balanced ligamentous/membranous tension and indirect fluidic technique.

RESULTS

During the study period 345 patients underwent surgery for symptomatic endometriosis. Among them, 97 patients (28.1%) complained of post-operative persistent CPP and dyspareunia and 69 patients underwent osteopathic treatment. OMT reports showed a significant improvement of the symptoms after the first OMT session. Particularly, lower scores of CPP (mean NRS 4±4.2 vs. 0.2±0.7, P value.

CONCLUSIONS

OMT, breaking the cycle of pain and normalizing the musculoskeletal pelvic activity, could be a successful technique to treat persistent chronic pain in women surgically treated for endometriosis.

High-fat diets promote peritoneal inflammation and augment endometriosis-associated abdominal hyperalgesia

Immune dysfunction is one of the central components in the development and progression of endometriosis by establishing a chronic inflammatory environment. Western-style high-fat diets (HFD) have been linked to greater systemic inflammation to cause metabolic and chronic inflammatory diseases, and are also considered an environmental risk factor for gynecologic diseases. Here, we aimed to examine how HFD cause an inflammatory environment in endometriosis and discern their contribution to endometriotic-associated hyperalgesia. Our results showed that HFD-induced obesity enhanced abdominal hyperalgesia that was induced by endometriotic lesions. Peritoneal inflammatory macrophages and cytokine levels increased by lesion induction were elevated by chronic exposure to HFD. Increased expression of pain-related mediators in the dorsal root ganglia was observed after lesion induction under the HFD condition. Although HFD did not affect inflammatory macrophages in the peritoneal cavity without lesion induction, the diversity and composition of the gut microbiota were clearly altered by HFD as a sign of low-grade systemic inflammation. Thus, HFD alone might not establish a local inflammatory environment in the pelvic cavity, but it can contribute to further enhancing chronic inflammation, leading to the exacerbation of endometriosis-associated abdominal hyperalgesia following the establishment and progression of the disease.

The effect of antioxidant supplementation on dysmenorrhea and endometriosis-associated painful symptoms: a systematic review and meta-analysis of randomized clinical trials

This study aimed to review randomized controlled trials (RCTs) investigating the effects of dietary antioxidant supplements on the severity of endometriosis-related pain symptoms. The PubMed/Medline, Scopus, and Web of Science databases were searched until April 2022. Additionally, we manually searched the reference lists. Endpoints were summarized as standardized mean difference (SMD) with 95% confidence intervals (CIs) in a random-effects model. The I2 statistic was used to assess heterogeneity. Ten RCTs were included in this meta-analysis. Overall, 10 studies were related to dysmenorrhea, four to dyspareunia, and four to pelvic pain. Antioxidants significantly reduced dysmenorrhea (SMD, -0.48; 95% CI, -0.82 to -0.13; I2=75.14%). In a subgroup analysis, a significant reduction of dysmenorrhea was observed only in a subset of trials that administered vitamin D (SMD, -0.59; 95% CI, -1.13 to -0.06; I2=69.59%) and melatonin (SMD, -1.40; 95% CI, -2.47 to -0.32; I2=79.15%). Meta-analysis results also suggested that antioxidant supplementation significantly improved pelvic pain (SMD, -1.51; 95% CI, -2.74 to -0.29; I2=93.96%), although they seem not to have a significant beneficial impact on the severity of dyspareunia. Dietary antioxidant supplementation seems to beneficially impact the severity of endometriosis-related dysmenorrhea (with an emphasis on vitamin D and melatonin) and pelvic pain. However, due to the relatively small sample size and high heterogeneity, the findings should be interpreted cautiously, and the importance of further well-designed clinical studies cannot be overstated.

Crimson clues: advancing endometriosis detection and management with novel blood biomarkers

Endometriosis is an inflammatory condition affecting approximately 10% of the female-born population. Despite its prevalence, the lack of noninvasive biomarkers has contributed to an established global diagnostic delay. The intricate pathophysiology of this enigmatic disease may leave signatures in the blood, which, when detected, can be used as noninvasive biomarkers. This review provides an update on how investigators are utilizing the established disease pathways and innovative methodologies, including genome-wide association studies, next-generation sequencing, and machine learning, to unravel the clues left in the blood to develop blood biomarkers. Many blood biomarkers show promise in the discovery phase, but because of a lack of standardized and robust methodologies, they rarely progress to the development stages. However, we are now seeing biomarkers being validated with high diagnostic accuracy and improvements in standardization protocols, providing promise for the future of endometriosis blood biomarkers.

Kallikrein-Related Peptidase 4 Promotes Proliferation, Migration, Invasion, and Pro-Angiogenesis of Endometrial Stromal Cells via Regulation of Brain-Derived Neurotrophic Factor Production in Endometriosis

Endometriosis is a common benign gynecologic condition. Endometriosis lesions are associated with endometrial cell proliferation, migration, invasion, and neovascularization, while the specific molecular mechanisms are still elusive. Transcriptome sequencing has been used for the identification of diagnostic markers in endometriosis. Here, transcriptome profiling revealed that kallikrein-related peptidase 4 (KLK4) expression was up-regulated in ectopic endometrium (EC) tissues of patients with endometriosis. KLK4 mediates the degradation of extracellular matrix proteins, and its proteolytic activity activates many tumorigenic and metastatic pathways via tumor invasion and migration. Nevertheless, whether KLK4 serves as an important regulatory factor in endometriosis remains unclear. This study confirmed that KLK4 was highly expressed in ectopic endometrial stromal cells (EC-ESCs). KLK4 overexpression promoted proliferation and suppressed apoptosis of EC-ESCs, induced cell migration and invasion, and enhanced angiogenesis in vivo. Mechanistically, KLK4 overexpression mediated the protein cleavage of pro-brain-derived neurotrophic factor in EC-ESCs. Finally, brain-derived neurotrophic factor was a vital downstream substrate of KLK4 maintained the proliferation, metastasis, and pro-angiogenesis abilities and inhibited apoptosis of ESCs through a rescue study. Together, these findings demonstrate the promotive role of KLK4 in endometriosis development. In addition, the study provides a new insight that KLK4 might be a potential therapeutic target and prognostic marker for patients with endometriosis.

High-fat diets promote peritoneal inflammation and augment endometriosis-associated abdominal hyperalgesia

Immune dysfunction is one of the central components in the development and progression of endometriosis by establishing a chronic inflammatory environment. Western-style high-fat diets (HFD) have been linked to greater systemic inflammation to cause metabolic and chronic inflammatory diseases, and are also considered an environmental risk factor for gynecologic diseases. Here, we aimed to examine how HFD alter an inflammatory environment in endometriosis and discern their contribution to endometriotic-associated hyperalgesia. Our results showed that HFD-induced obesity enhanced abdominal mechanical allodynia that was induced by endometriotic lesions. Peritoneal inflammatory macrophages and cytokine levels increased by lesion induction were elevated by chronic exposure to HFD. Pain-related mediators in the dorsal root ganglia were further stimulated after lesion induction under the HFD condition. Although HFD did not affect inflammatory macrophages in the peritoneal cavity without lesion induction, the diversity and composition of the gut microbiota were clearly altered by HFD as a sign of low-grade systemic inflammation. Thus, HFD alone might not establish a local inflammatory environment in the pelvic cavity, but it can contribute to further enhancing chronic inflammation, leading to the exacerbation of endometriosis-associated abdominal hyperalgesia following the establishment and progression of the disease.

Clinical efficacy of a novel method of fertility-preserving adenomyomectomy in infertile women with diffuse adenomyosis

Beneficial and detrimental effect of surgical adenomyomectomy is still controversial in infertile women with severely diffuse adenomyosis. The primary objective of this study was to assess whether a novel method of fertility-preserving adenomyomectomy could improve pregnancy rates. The secondary objective was to evaluate whether it could improve dysmenorrhea and menorrhagia symptoms in infertile patients with severe adenomyosis. A prospective clinical trial was conducted between December 2007 and September 2016. Fifty women with infertility due to adenomyosis were enrolled in this study after clinical assessments by infertility experts. A novel method of fertility-preserving adenomyomectomy was performed on 45 of 50 patients. The procedure included T- or transverse H-incision of the uterine serosa followed by preparation of the serosal flap, excision of the adenomyotic tissue using argon laser under ultrasonographic monitoring, and a novel technique of suturing between the residual myometrium and serosal flap. After the adenomyomectomy, the changes in the amount of menstrual blood, relief of dysmenorrhea, pregnancy outcomes, clinical characteristics, and surgical features were recorded and analyzed. All patients obtained dysmenorrhea relief 6 months postoperatively (numeric rating scale [NRS]; 7.28 ± 2.30 vs 1.56 ± 1.30, P < .001). The amount of menstrual blood decreased significantly (140.44 ± 91.68 vs 66.33 ± 65.85 mL, P < .05). Of the 33 patients who attempted pregnancy postoperatively, 18 (54.5%) conceived either by natural means, in vitro fertilization and embryo transfer (IVF-ET), or thawing embryo transfer. Miscarriage occurred in 8 patients, while 10 (30.3%) had viable pregnancies. This novel method of adenomyomectomy resulted in improved pregnancy rates, as well as relief of dysmenorrhea and menorrhagia. This operation is effective in preserving fertility potential in infertile women with diffuse adenomyosis.

Status and related factors of postoperative recurrence of ovarian endometriosis: a cross-sectional study of 874 cases

PURPOSE

Exploring the status and related factors of postoperative recurrence of ovarian endometriosis.

METHODS

This study analyzed the results of questionnaires conducted in 27 hospitals across the country from January 2019 to November 2021. All women were divided into recurrence group and non-recurrence group to analyze the recurrence rate and related factors after ovarian endometriosis surgery.

RESULTS

The recurrence rates of ovarian endometriosis within 1 year, 1-2 years, 2-3 years, 3-4 years, 4-5 years and more than 5 years were 6.27%, 35.85%, 55.38%, 65.00% and 56.82%, respectively. Significant differences were found between two groups in terms of age at surgery (OR: 0.342, 95%CI: 0.244-0.481, P < 0.001), presence of dysmenorrhea (OR: 1.758, 95%CI: 1.337-2.312, P < 0.001), presence of adenomyosis (OR: 1.948, 95%CI: 1.417-2.678, P < 0.001) and family history of endometriosis or adenomyosis (OR: 1.678, 95%CI: 1.035-2.721, P = 0.021). The age at surgery (OR: 0.358, 95%CI: 0.253-0.506, P < 0.001), presence of dysmenorrhea (OR: 1.379, 95%CI: 1.026-1.853, P = 0.033) and presence of adenomyosis (OR: 1.799, 95%CI: 1.275-2.537, P = 0.001) were significantly associated with endometrioma recurrence in multivariate analysis. No significant associations were found between the recurrence rate and body mass index (BMI), educational background, age of menarche, gravida, parity, uterine leiomyoma, endometrial polyps or postoperative use of gonadotropin-releasing hormone agonist (GnRH-a).

CONCLUSIONS

Dysmenorrhea and presence of adenomyosis are independent risk factors for postoperative recurrence of ovarian endometriosis, and older age is an independent protective factor for postoperative recurrence.

The Expression of TGF-β1, SMAD3, ILK and miRNA-21 in the Ectopic and Eutopic Endometrium of Women with Endometriosis

The molecular pathogenesis of endometriosis has been associated with pathological alterations of protein expression via disturbances in homeostatic genes, miRNA expression profiles, and signaling pathways that play an essential role in the epithelial-mesenchymal transition (EMT) process. TGF-β1 has been hypothesized to play a key role in the development and progression of endometriosis, but the activation of a specific mechanism via the TGF-β-SMAD-ILK axis in the formation of endometriotic lesions is poorly understood. The aim of this study was to assess the expression of EMT markers (TGF-β1, SMAD3, ILK) and miR-21 in ectopic endometrium (ECE), in its eutopic (EUE) counterpart, and in the endometrium of healthy women. The expression level of the tested genes and miRNA was also evaluated in peripheral blood mononuclear cells (PBMC) in women with and without endometriosis. Fifty-four patients (n = 54; with endometriosis, n = 29, and without endometriosis, n = 25) were enrolled in the study. The expression levels (RQ) of the studied genes and miRNA were evaluated using qPCR. Endometriosis patients manifested higher TGF-β1, SMAD3, and ILK expression levels in the eutopic endometrium and a decreased expression level in the ectopic lesions in relation to control tissue. Compared to the endometrium of healthy participants, miR-21 expression levels did not change in the eutopic endometrium of women with endometriosis, but the RQ was higher in their endometrial implants. In PBMC, negative correlations were found between the expression level of miR-21 and the studied genes, with the strongest statistically significant correlation observed between miR-21 and TGF-β1. Our results suggest the loss of the endometrial epithelial phenotype defined by the differential expression of the TGF-β1, SMAD3 and ILK genes in the eutopic and ectopic endometrium. We concluded that the TGF-β1-SMAD3-ILK signaling pathway, probably via a mechanism related to the EMT, may be important in the pathogenesis of endometriosis. We also identified miR-21 as a possible inhibitor of this TGF-β1-SMAD3-ILK axis.

Brain Morphological and Functional Changes in Adenomyosis with Pain: A Resting State Functional Magnetic Resonance Imaging Study

The absence of clinically objective methods to evaluate adenomyosis-associated pain and the poor understanding of its pathophysiology lead to treatment limitations. We conducted a resting-state functional magnetic resonance imaging study with 49 patients with pain-related adenomyosis and 30 pain-free controls to investigate brain morphological alterations and regional dysfunctions in patients with pain-related adenomyosis. These patients had significantly higher scores for anxiety and depression than the control group (p < 0.05). They also had a lower gray matter volume (GMV) in the bilateral insula, left angular gyrus, precuneus, left inferior temporal gyrus, and left postcentral gyrus (p < 0.05, AlphaSim corrected). Similarly, decreased voxel-mirrored homotopic connectivity was observed in the bilateral insula, posterior cingulate cortex, middle frontal gyrus, and postcentral gyrus in the adenomyosis patient group (p < 0.05, AlphaSim corrected). Regional homogeneity showed significant differences mainly in the bilateral cerebellum, left inferior frontal gyrus, medial prefrontal cortex, and posterior cingulate gyrus. Correlation analysis showed that the degree of depression in patients with adenomyosis was negatively correlated with the GMV of the left angular gyrus. The results show that these patients exhibited changes in multiple brain regions associated with pain as well as emotion perception and processing.

BDNF and TrKB expression levels in patients with endometriosis and their associations with dysmenorrhoea

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is a known regulator of the development and maintenance of chronic pain in various chronic disorders. Together with its high-affinity tyrosine kinase type B (TrKB) receptor, BDNF is extensively expressed in the mammalian female reproductive system. However, BDNF and TrKB expression in different stages of endometriosis and the relationship between the expression of each in ectopic lesions and endometriosis pain remain unclear.

METHODS

Sixty-two women who underwent laparoscopic surgery were enrolled in this study: forty-six diagnosed with ovarian endometrioma (study group) and sixteen diagnosed with ovarian benign tumours (control group). Samples from eutopic endometrium and ovarian endometriotic lesions were obtained at laparoscopic surgery. BDNF and TrKB messenger RNA (mRNA) and proteins levels in the eutopic and ectopic endometrium of both groups were measured by real-time PCR and immunohistochemical staining, respectively. Before the surgery the visual analogue scale (VAS) was used to measure dysmenorrhoea.

RESULTS

BDNF and TrKB expression levels were higher in ovarian endometriotic lesions than in eutopic endometrium and normal endometrium (P < 0.05), and there was no cyclical change. Furthermore, their expression levels were higher in eutopic endometrium than in normal endometrium (P < 0.05), and BDNF and TrKB levels were higher in stage IV ovarian endometriotic lesions than in stage II and III lesions (P < 0.05), with their expression being non-significantly higher in stage III than in stage II (P > 0.05). Additionally, correlation coefficients for the association analysis between the mRNA expression of BDNF or TrKB in eutopic endometrium and the dysmenorrhoea VAS score were r = 0.52 and r = 0.56 for BDNF and TrKB, respectively (P < 0.05). The correlation coefficients for the associations between BDNF and TrKB in both the eutopic and ectopic endometrium were r = 0.82 and r = 0.66, respectively (P < 0.05).

CONCLUSIONS

BDNF and TrKB are closely related to dysmenorrhoea caused by endometriosis and may be important in the pathobiology or pathophysiology of endometriosis.

Macrophages Protect Endometriotic Cells Against Oxidative Damage Through a Cross-Talk Mechanism

This aim of this study was to investigate whether macrophages protect endometriotic cells from oxidative injury and to elucidate the underlying mechanisms of any protection. Endometriotic cells cultured with or without differentiated macrophages (dTHP-1 cells) were treated with hydrogen peroxide (H₂O₂) or methemoglobin, a major component of hemoglobin species in endometriotic cyst fluid. Co-culture experiments, microarray analysis, screening and validation of differentially expressed genes (DEGs), cell proliferation and viability assays, and experiments using a specific inhibitor were conducted to investigate the functional cross-talk between endometriotic cells and macrophages. Microarray analysis revealed that endometriotic cells co-cultured with dTHP-1 differentially express several genes compared with monoculture. Quantitative enzyme-linked immunosorbent assay (ELISA) and Western blotting analysis identified TGF-β1 as a promising candidate gene expressed in endometriotic cells co-cultured with dTHP-1 cells. TGF-β1 stimulated the expression of heme oxygenase-1 (HO-1) in dTHP-1 cells. HO-1 expression was increased in dTHP-1 cells co-cultured with endometriotic cells compared with the dTHP-1 monoculture. Both H₂O₂ and methemoglobin upregulated the expression of the HO-1 protein in the dTHP-1 monoculture; moreover, co-culture with endometriotic cells further enhanced HO-1 production. The co-culture with dTHP-1 protected endometriotic cells against oxidative injury. Blockade of HO-1 abolished the protective effects of macrophages. In an oxidative stress environment, TGF-β1 produced by endometriotic cells may protect against oxidative injury through the upregulation of macrophage-derived HO-1. The cross-talk between endometriotic cells and macrophages may contribute to the progression and pathogenesis of endometriosis.

The Anti-Endometriotic Effect of Cyperi Rhizoma Extract, Inhibiting Cell Adhesion and the Expression of Pain-Related Factors through Akt and NF-kB Pathways

Rhizomes of Cyperus rotundus have been widely used as a traditional medicine in Asia for the treatment of gynecological diseases. However, there is no scientific evidence demonstrating the effect of C. rotundus rhizomes on endometriosis, which is characterized by the adhesion of endometrial tissues outside the uterus, resulting in chronic and severe pelvic pain. The aim of this study was to investigate the effects of Cyperi rhizoma extract (CRE) on cell adhesion and the expression of pain-related factors (neurotrophins) in endometriotic cells, and to elucidate the underlying molecular mechanisms. CRE inhibited the adhesion of human endometriotic 12Z cells to peritoneal mesothelial Met5A cells using by adhesion assays. The mRNA expression of adhesion molecules [P-cadherin and matrix metalloproteinase (MMP)-2] was downregulated by CRE treatment. In addition, CRE significantly inhibited the mRNA expression of neurotrophins (BDNF, NGF, NT-3 and NT-4/5) in 12Z cells. Moreover, Akt overexpression markedly neutralized the inhibition of cell adhesion by CRE and expression of neurotrophins in 12Z cells. Furthermore, it was found that CRE suppressed NF-kB activation through the Akt pathway. These data suggest that CRE exerts anti-endometriotic activities by the inhibition of cell adhesion and neurotrophin expression, through the negative regulation of the Akt and NF-kB pathways in endometriotic cells.

Metformin as a Potential Treatment Option for Endometriosis

Endometriosis is a common disease in women of reproductive age, and its pathogenesis seems to be largely affected by hormone imbalance, inflammation, oxidative stress, and autophagy dysregulation. These pathophysiological disturbances interact with one another through mechanisms that are still awaiting elucidation. The aim of this article is to present current knowledge regarding the possibilities of using metformin in the pharmacological treatment of endometriosis. Metformin is an insulin sensitizer widely used for the treatment of type 2 diabetes mellitus. The pleiotropic effects of metformin are mainly exerted through the activation of AMP-activated protein kinase, which is the key cellular energy homeostasis regulator that inhibits mTOR, a major autophagy suppressor. Metformin regresses endometriotic implants by increasing the activity of superoxide dismutase. It is also an inhibitor of metalloproteinase-2, decreasing the levels of the vascular endothelial growth factor and matrix metalloproteinase-9 in animal studies. In endometriosis, metformin might modify the stroma-epithelium communication via Wnt2/β-catenin. With its unique therapeutic mechanisms and no serious side effects, metformin seems to be a helpful anti-inflammatory and anti-proliferative agent in the treatment of endometriosis. It could be a missing link for the successful treatment of this chronic disease.

Possible therapeutic effect of royal jelly on endometriotic lesion size, pain sensitivity, and neurotrophic factors in a rat model of endometriosis

Endometriosis is the abnormal growth of endometrial tissue. The goals of the study are: (1) Is any correlation between endometriosis pain and neurotrophins in the serum, dorsal root ganglion (DRG), and peritoneal fluid (PF) in rat models of experimental endometriosis?, (2) Possible therapeutic effects of royal jelly (RJ) on pain scores, size of endometriotic lesion, and neurotrophic factors. Forty-eight Sprague Dawley female rats weighing 205.023 ± 21.54 g were maintained in a standard condition. The rats were randomly divided into one of the six groups: Control (no intervention), Sham-1 (remove of uterine horn), RJ (administration of 200 mg/kg/day RJ for 21 days), Endometriosis (induction of endometriosis), Treatment (induction of endometriosis+administration of 200 mg/kg/day RJ for 21 days), and Sham-2 (induction of endometriosis+administration of water). Formalin test performed for pain evaluation. The levels of Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), substance P, and calcitonin gene-related peptide (CGRP) were measured by enzyme-linked immunosorbent assay. The mean pain scores in all three phases of the formalin test were significantly increased by endometriosis induction (p < 0.05). The concentrations of BDNF, NGF, and CGRP in DRG of the endometriosis group were significantly higher than these factors in the Control, Sham-1, and RJ groups (p < 0.05). RJ could significantly (p < 0.001) decrease the mean lesion size and the mean pain score in the late phase (p < 0.05). The present results determine that endometriosis pain may be related to nervous system neurotrophic factors. Treatment with RJ could decrease the size of endometriosis lesions as well as pain scores. The findings may shed light on other complementary and alternative remedies for endometriosis.

The Role of Abnormal Uterine Junction Zone in the Occurrence and Development of Adenomyosis

Adenomyosis is a benign disease with a malignant behavior, bothering a lot of women at reproductive age who suffer from increased menstruation, prolonged menstruation, progressive dysmenorrhea, and infertility. At present, there is no effective treatment for adenomyosis. It seriously affects the life quality of these patients. However, the pathogenesis of adenomyosis is not yet clear. Recently, uterus junctional zone, defined as the inner 1/3 of myometrium between endometrium and myometrium, has gained broad attention. As is reported, the structure and function disorder of uterus junctional zone may play an important part in the occurrence and development of adenomyosis. In this issue, the present study generally reviews the role of uterine junction zone and the related mechanisms involved in adenomyosis, such as the local micro-damage, the formation of inflammatory and hypoxic microenvironment, changes of cytokines, and abnormalities of miRNA as well as signal pathways. It will provide new insights and potential therapeutic target strategies for clinical strategies in the management of adenomyosis.

Niclosamide suppresses macrophage-induced inflammation in endometriosis†

Endometriosis is a common gynecological disease, which causes chronic pelvic pain and infertility in women of reproductive age. Due to limited efficacy of current treatment options, a critical need exists to develop new and effective treatments for endometriosis. Niclosamide is an efficacious and FDA-approved drug for the treatment of helminthosis in humans that has been used for decades. We have reported that niclosamide reduces growth and progression of endometriosis-like lesions via targeting STAT3 and NFĸB signaling in a mouse model of endometriosis. To examine the effects of niclosamide on macrophage-induced inflammation in endometriosis, a total of 29 stage III-IV endometrioma samples were used to isolate human endometriotic stromal cells (hESCs). M1 or M2 macrophages were isolated and differentiated from fresh human peripheral blood samples. Then, hESCs were cultured in conditioned media (CM) from macrophages with/without niclosamide. Niclosamide dose dependently reduced cell viability and the activity of STAT3 and NFκB signaling in hESCs. While macrophage CM stimulated cell viability in hESCs, niclosamide inhibited this stimulation. Macrophage CM stimulated the secretion of proinflammatory cytokines and chemokines from hESCs. Most of these secreted factors were inhibited by niclosamide. These results indicate that niclosamide is able to reduce macrophage-induced cell viability and cytokine/chemokine secretion in hESCs by inhibiting inflammatory mechanisms via STAT3 and/or NFκB signaling.

Pain catastrophizing is associated with pain thresholds for heat, cold and pressure in women with chronic pelvic pain

Background and aims Psychological traits such as pain catastrophizing may play a role in the development of chronic pelvic pain (CPP). Pain catastrophizing is the tendency to amplify negative cognitive and emotional pain processes. The Pain Catastrophizing Scale (PCS) assesses elements of pain catastrophizing divided into three subgroups of factors (rumination, helplessness and magnification). Previous studies have shown associations between CPP and increased pain sensitivity, widespread generalized hyperalgesia, and decreased pain thresholds, but the relation between pain catastrophizing and specific pain thresholds has not yet been widely examined in this patient group. The aims of this study were (a) to determine if catastrophizing is increased in women with CPP compared with pain-free women, (b) to assess the importance of pain catastrophizing, psychological distress variables, and subjective pain sensitivity for pain thresholds of heat, cold and pressure in these two groups, and (c) to determine whether psychological variables or pain thresholds best contribute to the differentiation between CPP and controls. Methods Thirty-seven women with chronic pelvic pain who underwent diagnostic laparoscopy on the suspicion of endometriosis participated along with 55 healthy and pain-free controls. All underwent quantitative sensory testing on six locations on the body to determine heat (HPT), cold (CPT) and pressure (PPT) pain thresholds. The PCS, the Pain Sensitivity Questionnaire (PSQ), the Hospital Anxiety Depression Scale, (HADS) demographics and clinical data were collected prospectively. Principal component analysis and orthogonal partial least square regressions were used to assess the associations between PCS scores and pain thresholds. Results The women with CPP scored significantly higher on PCS than the healthy controls. PCS-helplessness, PCS-rumination and HADS-depression were significantly associated with pain thresholds for the whole group. In the CPP group, PCS-rumination, body mass index and PSQ were significant regressors for HPT and CPT. The PCS and the HADS subscales were strongly intercorrelated in women with CPP and were stronger regressors of group membership than the three pain thresholds. In the group of healthy control women, no relationships were found to be significant. The psychological variables were somewhat stronger significant regressors than pain thresholds (also significant) for group membership. Conclusions Women with CPP have significantly higher pain catastrophizing scores than women without CPP. The pain catastrophizing rumination factor is significantly associated with pain thresholds of heat and cold in CPP women. PCS and HADS are strongly intercorrelated and PSQ correlates positively with these variables. It seems that the psychological variables are important for group differentiation. Implications The results clearly indicate the need for a multimodal assessment (bio-psycho-social) of CPP patients including psychological symptoms such as catastrophizing, anxiety and depression. The registration of semi-objective pain thresholds captures both specific pain sensitivity information (mechanical pressure, cold or heat) and the degree of wide spread pain hypersensitivity. There is a need for future larger studies investigating whether certain profiles in the clinical presentations (including pain thresholds and psychological variables) are associated with outcomes after different types of interventions.

Detection of nerve fibers in the eutopic endometrium of women with endometriosis, uterine fibroids and adenomyosis

Objective

The primary objective of this study was to establish the presence of nerve fibers in the eutopic endometrium of women with endometriosis and to determine whether these nerve fibers are exclusive to endometriosis or are also found in other pelvic pathologies associated with dysmenorrhea.

Methods

Endometrial tissue was obtained by aspiration (Pipelle), endometrial curettage, or following hysterectomy in women with endometriosis confirmed through histopathological examination, leiomyomas, and adenomyosis. The eutopic endometrium was subjected to immunohistochemical staining to detect PGP 9.5, which is a highly specific pan-neuronal marker. The nerve fiber density was correlated with the patient’s pain score, as indicated by the Visual Analog Scale. A control group was formed by staining the endometrium of women presenting with dysmenorrhea but without the above-mentioned disorders.

Results

Nerve fibers were observed in sections of the endo-myometrium (in the deep endometrium) in 68% of patients with endometriosis who underwent hysterectomy or a deep endometrial biopsy. Nerve fibers were not observed in the aspirated endometrium of women with endometriosis. Only 13.7% of women with adenomyosis and 3.3% of women with fibroids had nerve fibers in their endometrium. Nerve fiber density was correlated with pain score in women with endometriosis.

Conclusion

Nerve fibers were found in the functional layer of eutopic endometrium in women with endometriosis; hence, we concluded that the presence of nerve fibers in the eutopic endometrium could diagnose endometriosis with a fairly good specificity of 92.7%. However, the absence of nerve fibers does not always exclude the disease.

PPARγ Agonists: Emergent Therapy in Endometriosis

Endometriosis is one of the major gynecological diseases of reproductive-age women. This disease is characterized by the presence of glands and stroma outside the uterine cavity. Several studies have shown the major role of inflammation, angiogenesis, adhesion and invasion, and apoptosis in endometriotic lesions. Nevertheless, the mechanisms underlying endometriotic mechanisms still remain unclear and therapies are not currently efficient. The introduction of new agents can be effective by improving the condition of patients. PPARγ ligands can directly modulate these pathways in endometriosis. However, data in humans remain low. Thus, the purpose of this review is to summarize the potential actions of PPARγ agonists in endometriosis by acting on inflammation, angiogenesis, invasion, adhesion, and apoptosis.

Efficacy of niclosamide on the intra-abdominal inflammatory environment in endometriosis

Endometriosis, a common gynecological disease, causes chronic pelvic pain and infertility in women of reproductive age. Due to the limited efficacy of current therapies, a critical need exists to develop new treatments for endometriosis. Inflammatory dysfunction, instigated by abnormal macrophage (MΦ) function, contributes to disease development and progression. However, the fundamental role of the heterogeneous population of peritoneal MΦ and their potential druggable functions is uncertain. Here we report that GATA6-expressing large peritoneal MΦ (LPM) were increased in the peritoneal cavity following lesion induction. This was associated with increased cytokine and chemokine secretion in the peritoneal fluid (PF), as well as MΦ infiltration, vascularization and innervation in endometriosis-like lesions (ELL). Niclosamide, an FDA-approved anti-helminthic drug, was effective in reducing LPM number, but not small peritoneal MΦ (SPM), in the PF. Niclosamide also inhibits aberrant inflammation in the PF, ELL, pelvic organs (uterus and vagina) and dorsal root ganglion (DRG), as well as MΦ infiltration, vascularization and innervation in the ELL. PF from ELL mice stimulated DRG outgrowth in vitro, whereas the PF from niclosamide-treated ELL mice lacked the strong stimulatory nerve growth response. These results suggest LPM induce aberrant inflammation in endometriosis promoting lesion progression and establishment of the inflammatory environment that sensitizes peripheral nociceptors in the lesions and other pelvic organs, leading to increased hyperalgesia. Our findings provide the rationale for targeting LPM and their functions with niclosamide and its efficacy in endometriosis as a new non-hormonal therapy to reduce aberrant inflammation which may ultimately diminish associated pain.

Clinical characteristics of perineal endometriosis: A case series

BACKGROUND

The prevalence of perineal endometriosis (PEM) is low among women with endometriosis (EM) treated by surgery. It manifests as hard or cystic nodules with pain in the perineal wounds and surrounding areas. Implantation theory is regarded as the main pathogenesis of PEM. There are few clinical studies on the incidence and clinical characteristics of PEM. This study aims to summarize the clinical data of 14 PEM cases and analyze the factors that may be related to the incubation period and pain.

AIM

To analyze the medical history, clinical manifestations, diagnosis, treatment and treatment effect of PEM.

METHODS

The present study is a case series. We collected the clinical data and follow-up data of 14 patients with PEM who visited The International Peace Maternal and Child Health Hospital Affiliated to Shanghai Jiaotong University from January 2009 to December 2019. Paired t test and Pearson correlation analysis were used for statistical analysis. P < 0.05 was considered statistically significant.

RESULTS

The 14 patients included had a history of vaginal delivery. All patients underwent PEM lesion resection. Three patients were treated by levator ani muscle repair at the same time and 1 patient underwent extensive PEM lesion resection and anal sphincter repair. Body mass index (BMI) at delivery and BMI within 1 mo after delivery were negatively correlated with the latent period, respectively (R² = 0.53/0.86, P < 0.05). The average visual analog scale score in lesions at the third month after surgery was 0.57 ± 1.28 for all patients, which was significantly lower than that prior to surgery (P < 0.05). One patient relapsed during the sixth month after surgery, and to date, no recurrence occurred after the second surgery.

CONCLUSION

The higher the BMI during delivery and within 1 mo after delivery, the shorter the incubation period of PEM. It is very important to evaluate the location of lesions before surgery. Surgical resection of the lesion is the best treatment for PEM and results in significant alleviation of symptoms. Therefore, following the diagnosis of PEM, immediate surgery is recommended.

Assessing Pain Behavioral Responses and Neurotrophic Factors in the Dorsal Root Ganglion, Serum and Peritoneal Fluid in Rat Models of Endometriosis

Objective: Pain is the most frequently reported symptom involving in endometriosis. The alterations of neurotrophic factors and certain neuropeptides in the dorsal root ganglion (DRG), as well as serum and peritoneal fluid (PF), were evaluated in rat models of endometriosis.

Materials and methods: Twenty-four Sprague Dawley female rats were selected and maintained in a standard condition with 12 hours’ dark-light cycles. All the rats were randomly assigned to 3 groups: Control (intact rats); Sham (the operation was conducted without endometriosis induction); and Endometriosis (endometriosis induction was performed). The formalin test was performed for all groups on the first and the 21^st day of the study. The assessments of Brain-Derived Neurotrophic Factor (BDNF), Nerve Growth Factor (NGF), Calcitonin Gene-Related Peptide (CGRP), and Substance P levels were carried out by enzyme-linked immunosorbent assay (Elisa). The data were analyzed by One-Way ANOVA. The Tukey’s test was used as post-hoc.

Results: Endometriosis induction significantly increased the mean pain scores in the endometriosis group in all three phases of the formalin test. The concentrations of DRG-CGRP (p=0.035), BDNF (p<0.001), and NGF (p=0.006) in the endometriosis group were significantly higher than that of the other groups while serum-BDNF (p<0.001), Substance P (p=0.009), and NGF (p=0.015) were significantly lower in endometriosis group compared to other groups. The concentrations of PF-BDNF (p=0.025) and Substance P (p=0.009) were significantly lower than those of other groups.

Conclusion: The present results delineate that endometriosis induction could lead to hyperalgesia. This may be related to the significant increases in the BDNF, NGF, and CGRP in DRG.

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

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

Novel Technology to Capture Objective Data from Patients' Recovery from Laparoscopic Endometriosis Surgery

STUDY OBJECTIVE

To assess the feasibility of a noncontact radio sensor as an objective measurement tool to study postoperative recovery from endometriosis surgery.

DESIGN

Prospective cohort pilot study.

SETTING

Center for minimally invasive gynecologic surgery at an academically affiliated community hospital in conjunction with in-home monitoring.

PATIENTS

Patients aged above 18 years who sleep independently and were scheduled to have laparoscopy for the diagnosis and treatment of suspected endometriosis.

INTERVENTIONS

A wireless, noncontact sensor, Emerald, was installed in the subjects' home and used to capture physiologic signals without body contact. The device captured objective data about the patients' movement and sleep in their home for 5 weeks before surgery and approximately 5 weeks postoperatively. The subjects were concurrently asked to complete a daily pain assessment using a numeric rating scale and a free text survey about their daily symptoms.

MEASUREMENTS AND MAIN RESULTS

Three women aged 23 years to 39 years and with mild to moderate endometriosis participated in the study. Emerald-derived sleep and wake times were contextualized and corroborated by select participant comments from retrospective surveys. In addition, self-reported pain levels and 1 sleep variable, sleep onset to deep sleep time, showed a significant (p <.01), positive correlation with next-day-pain scores in all 3 subjects: r = 0.45, 0.50, and 0.55. In other words, the longer it took the subject to go from sleep onset to deep sleep, the higher their pain score the following day.

CONCLUSION

A patient's experience with pain is challenging to meaningfully quantify. This study highlights Emerald's unique ability to capture objective data in both preoperative functioning and postoperative recovery in an endometriosis population. The utility of this uniquely objective data for the clinician-patient relationship is just beginning to be explored.

Pathophysiological Basis of Endometriosis-Linked Stress Associated with Pain and Infertility: A Conceptual Review

Women with endometriosis are often under stress due to the associated pain, infertility, inflammation-related and other comorbidities including cancer. Additionally, these women are also under stress due to taboos, myths, inter-personal troubles surrounding infertility and pain of the disease as well as due to frequent incidences of missed diagnosis and treatment recurrence. Often these women suffer from frustration and loss of valuable time in the prime phase of life. All these complexities integral to endometriosis posit a hyperstructure of integrative stress physiology with overt differentials in effective allostatic state in women with disease compared with disease-free women. In the present review, we aim to critically examine various aspects of pathophysiological basis of stress surrounding endometriosis with special emphasis on pain and subfertility that are known to affect the overall health and quality of life of women with the disease and promising pathophysiological basis for its effective management.

Curcumin and Endometriosis

Endometriosis is one of the main common gynecological disorders, which is characterized by the presence of glands and stroma outside the uterine cavity. Some findings have highlighted the main role of inflammation in endometriosis by acting on proliferation, apoptosis and angiogenesis. Oxidative stress, an imbalance between reactive oxygen species and antioxidants, could have a key role in the initiation and progression of endometriosis by resulting in inflammatory responses in the peritoneal cavity. Nevertheless, the mechanisms underlying this disease are still unclear and therapies are not currently efficient. Curcumin is a major anti-inflammatory agent. Several findings have highlighted the anti-oxidant, anti-inflammatory and anti-angiogenic properties of curcumin. The purpose of this review is to summarize the potential action of curcumin in endometriosis by acting on inflammation, oxidative stress, invasion and adhesion, apoptosis and angiogenesis.

Endometriotic inflammatory microenvironment induced by macrophages can be targeted by niclosamide†

Endometriosis causes severe chronic pelvic pain and infertility. We have recently reported that niclosamide treatment reduces growth and progression of endometriosis-like lesions and inflammatory signaling (NF${\rm \small K}$B and STAT3) in a mouse model. In the present study, we examined further inhibitory mechanisms by which niclosamide affects endometriotic lesions using an endometriotic epithelial cell line, 12Z, and macrophages differentiated from a monocytic THP-1 cell line. Niclosamide dose dependently reduced 12Z viability, reduced STAT3 and NF${\rm \small K}$B activity, and increased both cleaved caspase-3 and cleaved PARP. To model the inflammatory microenvironment in endometriotic lesions, we exposed 12Z cells to macrophage conditioned media (CM). Macrophages were differentiated from THP-1 cells using 12-O-tetradecanoylphorbol-13-acetate as M0, and then M0 macrophages were polarized into M1 or M2 using LPS/IFNγ or IL4/IL13, respectively. Conditioned media from M0, M1, or M2 cultures increased 12Z viability. This effect was blocked by niclosamide, and cell viability returned to that of CM from cells treated with niclosamide alone. To assess proteins targeted by niclosamide in 12Z cells, CM from 12Z cells cultured with M0, M1, or M2 with/without niclosamide were analyzed by cytokine/chemokine protein array kits. Conditioned media from M0, M1, and/or M2 stimulated the secretion of cytokines/chemokines from 12Z cells. Production of most of these secreted cytokines/chemokines in 12Z cells was inhibited by niclosamide. Knockdown of each gene in 12Z cells using siRNA resulted in reduced cell viability. These results indicate that niclosamide can inhibit the inflammatory factors in endometriotic epithelial cells stimulated by macrophages by targeting STAT3 and/or NF${\rm \small K}$B signaling.

Modular Characteristics and Mechanism of Action of Herbs for Endometriosis Treatment in Chinese Medicine: A Data Mining and Network Pharmacology-Based Identification

Endometriosis is a common benign disease in women of reproductive age. It has been defined as a disorder characterized by inflammation, compromised immunity, hormone dependence, and neuroangiogenesis. Unfortunately, the mechanisms of endometriosis have not yet been fully elucidated, and available treatment methods are currently limited. The discovery of new therapeutic drugs and improvements in existing treatment schemes remain the focus of research initiatives. Chinese medicine can improve the symptoms associated with endometriosis. Many Chinese herbal medicines could exert antiendometriosis effects via comprehensive interactions with multiple targets. However, these interactions have not been defined. This study used association rule mining and systems pharmacology to discover a method by which potential antiendometriosis herbs can be investigated. We analyzed various combinations and mechanisms of action of medicinal herbs to establish molecular networks showing interactions with multiple targets. The results showed that endometriosis treatment in Chinese medicine is mainly based on methods of supplementation with blood-activating herbs and strengthening qi. Furthermore, we used network pharmacology to analyze the main herbs that facilitate the decoding of multiscale mechanisms of the herbal compounds. We found that Chinese medicine could affect the development of endometriosis by regulating inflammation, immunity, angiogenesis, and other clusters of processes identified by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The antiendometriosis effect of Chinese medicine occurs mainly through nervous system–associated pathways, such as the serotonergic synapse, the neurotrophin signaling pathway, and dopaminergic synapse, among others, to reduce pain. Chinese medicine could also regulate VEGF signaling, toll-like reporter signaling, NF-κB signaling, MAPK signaling, PI3K-Akt signaling, and the HIF-1 signaling pathway, among others. Synergies often exist in herb pairs and herbal prescriptions. In conclusion, we identified some important targets, target pairs, and regulatory networks, using bioinformatics and data mining. The combination of data mining and network pharmacology may offer an efficient method for drug discovery and development from herbal medicines.

Central Sensitization-Related Changes in Brain Function Activity in a Rat Endometriosis-Associated Pain Model

Background

Pain sensitization processing in the central nervous system may be related to endometriosis-associated pain in patients. The purpose of this study was to understand the alterations in the abnormal pain response in central brain areas and explore the central sensitization mechanism of endometriosis-associated pain.

Methods

An endometriosis model was established in 40 Sprague-Dawley rats, and the rats underwent pain model assessment through behavioral tests. Twenty Sprague-Dawley rats underwent a sham operation as the control group. Thirteen pain rats and 8 control rats received Rs-fMRI examination to explore the brain functional activity areas, and the regional homogeneity (ReHo) method was used to analyze relevant functional signals among the whole brain. The states of neurons and expression of TRPV1 and NMDRA located in the abnormal ReHo signal brain regions were observed using Nissl staining, qRT-PCR and immunohistochemistry.

Results

The rats were divided into a pain group and a control group based on the different syndromes and behavioral assessments. We detected significant enhancement of ReHo signals in the anterior cingulate cortex, hippocampus, and thalamus and a reduction in the ReHo values in the basomedial amygdaloid nucleus (BM) and primary motor cortex (M1) in the pain rat group via Rs-fMRI examination. The number of Nissl bodies and apoptotic neurons was increased; moreover, the volume of neurons increased compensatorily in the cingulate cortex, thalamus and hippocampus in the pain group. TRPV1 and NMDRA were overexpressed in apoptotic neurons in the higher ReHo value brain regions in the endometriosis pain group.

Conclusion

These findings suggest that in rats with endometriosis-associated pain, ReHo signal enhancement was observed in the cingulate cortex, thalamus and hippocampus, which may be due to the increase in the number of apoptotic neurons or the compensatory increase in the volume of overactive neurons.

Associations between pain thresholds for heat, cold and pressure, and Pain Sensitivity Questionnaire scores in healthy women and in women with persistent pelvic pain

BACKGROUND

The Pain Sensitivity Questionnaire (PSQ) is a self-rating instrument developed as a time- and cost-saving alternative to quantitative sensory testing (QST). The aims of the study were to assess (a) the associations between PSQ scores and QST in women with persistent pelvic pain and in pain-free controls and (b) to what extent demographic variables and psychological distress influenced PSQ scores.

METHODS

Fifty-five healthy women and 37 women with persistent pelvic pain participated. All filled in the PSQ and Hospital Anxiety and Depression Scale and had QST (heat, cold and pressure pain thresholds) performed on six locations on the body. Information on age, body mass index, smoking habits and pain duration were collected. Principal component analysis and orthogonal partial least square regressions were used.

RESULTS

The patients scored significantly higher on PSQ than the controls. Significant multivariate correlations between pain thresholds and PSQ scores were found only in the patient group. In the patient group, the heat and cold pain thresholds correlated more strongly with PSQ scores than the pressure pain threshold.

CONCLUSIONS

The PSQ score was significantly higher in pelvic pain patients, and correlations between QSTs and the PSQ were only found for patients.

SIGNIFICANCE

The PSQ reflects pain sensitivity in women with PPP and can be used as a non-invasive and painless way to assess this condition in clinical practice.

Effect of Dehydrocostus Lactone Isolated from the Roots of Aucklandia lappa on the Apoptosis of Endometriotic Cells and the Alternative Activation of Endometriosis-Associated Macrophages

The roots of Aucklandia lappa have been used in traditional medicine in Asia to treat inflammation and diseases associated with pain, including endometriosis. The aim of this study was to investigate the anti-endometriotic effect of dehydrocostus lactone, an active compound in A. lappa roots, using human endometriotic cells and macrophages stimulated by these cells. Dehydrocostus lactone induced apoptotic cell death in 12Z human endometriotic cells. Dehydrocostus lactone stimulated the activation of caspase-3, -8, and -9, while caspase inhibitors significantly reversed the dehydrocostus lactone-induced cell death in 12Z cells. In addition, dehydrocostus lactone decreased the production of PGE₂ and neurotrophins (BDNF, NGF, NT3, and NT4/5), which are regarded as endometriosis-associated pain factors in human endometriotic cells. Moreover, dehydrocostus lactone inhibited the expression of M2 markers (CD206, and Trem-2), IL-10, VEGF, and MMP-2/-9 in endometriosis-associated macrophages (EAMs). Furthermore, dehydrocostus lactone inhibited the Akt and NFκB pathways in both endometriotic cells and EAMs. Taken together, our findings suggest that dehydrocostus lactone, an active compound of A, lappa, has anti-endometriotic activities via induction of apoptosis and downregulation of pain factors in endometriotic cells and inhibition of the alternative activation of EAMs.

The role of inflammation, oxidative stress, angiogenesis, and apoptosis in the pathophysiology of endometriosis: Basic science and new insights based on gene expression

Endometriosis is a frequent and chronic illness in young women which could be defined by the existence of endometrial stroma and glands outside of the normal site of the lining of the uterus. It has painful symptoms. The advanced stage of endometriosis may lead to gynecological malignancies, such as ovarian cancer, and other complications, including infertility. However, its exact physiopathology is not well known. Recent studies have shown the possible roles of inflammation along with oxidative stress. Additionally, angiogenesis and apoptosis dysregulation contribute to endometriosis pathophysiology. Therapeutic strategies and continuing attempts, to conquer endometriosis should be done regarding molecular signaling pathways. Thus, the present review summarizes current studies and focuses on molecular mechanisms.

A detailed profile of pain in severe endometriosis

Objective:

To investigate the detailed nature of pain symptoms reported by women with endometriosis and those without current gynecological complaint.

Design:

Self-administered cross-sectional study was conducted using a structured questionnaire.

Setting:

Teaching hospital clinic, specialist gynecologist, and family practice patients; endometriosis community support group members; and university staff and students.

Subjects:

A total of 737 women returned completed surveys: women with endometriosis ( n = 529) and with no current gynecological complaint ( n = 208).

Intervention(s):

None.

Main outcome measure(s):

Demographics, experience of pain symptoms: frequency, severity, and characteristics.

Results:

All pain symptoms were significantly more common among women with endometriosis compared with controls. Women with endometriosis all reported experiencing dysmenorrhea to some degree ( N = 527, two missing), although the severity was “slight” for 5%. Dyspareunia was reported by 92% of women with endometriosis, most commonly during intercourse, rather than at the start or post-coital. The other pain symptoms experienced by women with endometriosis, in order of frequency, were lower back pain (93%), pain at ovulation (87%), pelvic pain other than during menses, ovulation, urination or intercourse (79%), dysuria (71%), and rectal pain (67%). The great majority of women with endometriosis reported multiple sources and types of pain. Among women with endometriosis there were clear associations between the severity of dysmenorrhea and the frequency of experiencing dyspareunia and other pain symptoms.

Conclusion:

Pain symptoms in women with endometriosis were generally much more extensive and complex than recognized by most clinicians.

The nervous system and genomics in endometriosis

Endometriosis is a gynaecological disease that occurs in approximately 10% to 15% of women of reproductive age and up to 47% of infertile women. The presence of implants of endometrial-like glands and stroma outside the uterus, characteristic of this disease, induce a wide variety of symptoms, mainly pelvic pain and infertility. Women suffering from this condition experience great distress, which significantly affects their quality of life. Numerous studies attempting to decipher the pathogenic mechanisms of endometriosis have been conducted around the world, yet its aetiology still remains unknown. It is widely believed that in women with endometriosis, the endometrium has characteristic features that allow the formation of implants once fragments have entered the peritoneal cavity through retrograde menstruation. Furthermore, a strong genetic tendency to develop the disease has been reported among patients and first-degree relatives. Thanks to the recent technological advances achieved in genomics and bioinformatics, a number of studies have had the potential to analyse several aspects of the pathogenesis of endometriosis from a genetic perspective. Due to the recent identification of nerve fibres in the endometrium of women with endometriosis, research on the neurogenesis of the disease has increased in the past few years. However, the genetic aspects of nerve growth in endometriosis have not been analysed in depth and further research providing important insights into the mechanisms that mediate pain in affected patients has the potential to contribute substantially to the future management of the condition.

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.

Perineural invasion in endometriotic lesions contributes to endometriosis-associated pain

Purpose

Recent studies have shown that abnormal distribution of pelvic nerves contributes to endometriosis-associated pain. However, the relationship between neurogenesis and pain severity in endometriosis still remains uncertain, which makes it an enigma for both gynecologists as well as neuropathologists. In this study, we tried to explore a special phenomenon, perineural invasion (PNI), in deep infiltrating endometriosis (DIE) and investigated the correlation between PNI- and DIE-associated pain.

Patients and methods

The study was conducted in the Department of Obstetrics and Gynecology of the First Affiliated Hospital of Sun Yat-sen University from June 2012 to January 2015. In total, 64 patients with DIE were enrolled. They received laparoscopically surgical resection of endometriotic lesions. The Kruskal–Wallis and Mann–Whitney tests were used for comparisons of enumeration data. Spearman rank correlation was used for linear analysis.

Results

Immunohistochemical analysis demonstrated that PNI was commonly found in DIE lesions. Patients were divided into PNI (+) group and PNI (−) group. The visual analog scale scores of dysmenorrhea, dyspareunia, and chronic pelvic pain were higher in PNI (+) group than in PNI (−) group. Also, we found significantly increased density of newly formed nerve fibers as well as microvessels in lesions of PNI (+) group. Further, double immunofluorescence showed a closely spatial nerve–vessel network in the endometriotic lesion of PNI (+) group. More importantly, correlation analysis revealed positive relation between the density of newly formed nerve fibers in the lesion and the density of microvessels in lesions of PNI (+) group.

Conclusion

This study suggests that PNI in endometriotic lesions plays an important role in endometriosis-associated pain, mainly through a mechanism named “neuroangiogenesis”.

Inflammatory cytokine profile of co‑cultivated primary cells from the endometrium of women with and without endometriosis

Endometriosis is a chronic gynecological disorder defined as the presence of endometrial tissue within extra-uterine sites. The primary symptoms are infertility and chronic pain. The inflammatory environment and aberrant immune responses in women with endometriosis may be directly associated with the initiation and progression of endometriotic lesions. In the present study, the secretion of inflammatory cytokines was evaluated in cultures of primary endometrial cells (ECs) isolated from the endometrium of women with and without endometriosis. The presence of endometriotic cells leads to alterations in the secretory profile of healthy ECs. The expression of the inflammatory cytokines interleukin (IL)‑6 and IL‑8 was significantly increased in endometriotic and co‑cultured cells compared with healthy ECs. IL‑6 expression was strongly correlated with IL‑8 expression in endometriotic cells. IL‑1β expression was increased on day 10 of co‑culture to 48.30 pg/ml and may be associated with the long‑term co‑culture, rather than IL‑6 and IL‑8 expression. IL‑6 expression was strongly correlated with cell number, whereas IL‑8 expression was moderately correlated with cell number. Additionally, it was observed that co‑cultured cells exhibited a different population of cells, with expression of the mesenchymal stem cell marker cell surface glycoprotein MUC18, indicating a putative role of endometrial mesenchymal stem cells in the secretion of cytokines and disease development. These results indicate a predominant role of primary endometriotic cells in the secretion of cytokines, which contributes to the disrupted peritoneal and endometrial environment observed in the women with endometriosis.

Increased serum levels of mBDNF in women with minimal and mild endometriosis have no predictive power for the disease

The objective of our pilot clinical, prospective study was to determine the serum levels of mature brain-derived neurotrophic factor, in of women with endometriosis and controls and explore whether mature brain-derived neurotrophic factor is a potential biomarker for the disease. The patients were selected from the Endometriosis Marker Austria prospective cohort study conducted at the tertiary referral certified Endometriosis Center of the Medical University of Vienna. All women underwent laparoscopic surgery because there was a suspicion of endometriosis, or the women had pelvic pain, adnexal cysts, unexplained infertility, or uterine fibroids. Our main outcome parameter was total levels of mature brain-derived neurotrophic factor in serum, measured using ELISA. Our results show that serum levels of mature brain-derived neurotrophic factor are significantly higher in women with endometriosis compared to women without endometriosis. The mean serum protein levels are significantly higher in women with rAFS stage I and II endometriosis, whereas no difference was found in women with stage III and IV endometriosis and controls. Postoperative follow-up at 6-10 weeks revealed that surgical intervention leads to equilibration of the levels of secreted mature brain-derived neurotrophic factor between women with and without endometriosis. The difference between serum mature brain-derived neurotrophic factor levels of women with endometriosis compared to women without endometriosis is independent of menstrual cycle phase and overall self-reported pelvic pain. ROC-curve analysis showed that, the mature brain-derived neurotrophic factor is not a useful biomarker for endometriosis. In conclusion, although women with stage I and II endometriosis have increased levels of mature brain-derived neurotrophic factor in serum compared to controls, the difference is not predictive for the disease. Impact statement Endometriosis is a disease that can have a significant impact on the quality of life of affected women. The gold standard for diagnosis to this day remains visualization through laparoscopic surgery with histological verification. Current studies are attempting to find a biomarker with high sensitivity and specificity, which would bypass the surgery-associated risks and would significantly reduce costs. In an attempt to elucidate whether mature serum BDNF can serve as diagnostic marker for the disease, we compared the levels of the protein in women with endometriosis to endometriosis-free controls. While our results showed that serum concentrations of the mature protein were significantly higher in women with endometriosis, we did not find this marker to have the sensitivity or specificity needed in order to allow a reliable diagnosis.

The Role of Magnetic Resonance Imaging-Diffusion Tensor Imaging in Predicting Pain Related to Endometriosis: A Preliminary Study

OBJECTIVES

To evaluate the sacral nerve root features by the means of magnetic resonance imaging-diffusion tensor imaging (MRI-DTI) tractography in women with endometriosis and/or adenomyosis, and to analyze the correlations among DTI abnormalities, pain symptoms, and endometriotic lesions found at surgery.

DESIGN

A cross-sectional, observational study (Canadian Task Force classification II-2).

SETTING

University hospital.

PATIENTS

Women (n = 76) with clinical suspicion of endometriosis.

INTERVENTIONS

Before surgery, dysmenorrhea, deep dyspareunia, and noncyclic pelvic pain (NCPP) were assessed using a 10-point visual analog scale. MRI enabled a 3-dimensional reconstruction of S1, S2, and S3. Fractional anisotropy was calculated for each root. Laparoscopic treatment of endometriosis was performed in 56 patients.

MEASUREMENTS AND MAIN RESULTS

Our findings revealed correlations among sacral root reconstruction by MRI-DTI, pain symptoms, and laparoscopic findings. DTI of sacral roots revealed a regular and homogeneous appearance in 17 patients (25.8%) and abnormalities in microstructure reconstruction, with fiber irregularities and disorganization and loss of the simple unidirectional course, in 44 patients (66.7%). At laparoscopy, ovarian endometriomas were found in 82.1% of the patients, and deeply infiltrating endometriosis (DIE) were found in 57.1%. Endometriosis was staged according to the revised American Society for Reproductive Medicine classification. Pathological DTI findings were significantly associated with the severity of dysmenorrhea and NCPP, pain duration, presence of tubo-ovarian and cul-de-sac adhesions, and DIE.

CONCLUSION

The presence of pathological DTI findings of the sacral nerve roots correlates with the type of pain, adhesions, and DIE. At present, DTI can be useful for providing a better understanding of pain; however, DTI could become a useful tool in therapeutic planning for patients with endometriosis.

P2X3 receptor involvement in endometriosis pain via ERK signaling pathway

The purinergic receptor P2X ligand-gated ion channel 3 (P2X3) is crucially involved in peripheral nociceptive processes of somatic and visceral pain. Endometriosis pain is considered as a kind of inflammatory and neuropathic pain. However, whether P2X3 is involved in endometriosis pain has not been reported up to date. Here, we aimed to determine whether P2X3 expression in endometriotic lesions is involved in endometriosis pain, which is regulated by inflammatory mediators through extracellular regulated protein kinases (ERK) signalling pathway. We found that P2X3 expressions in endometriosis endometrium and endometriotic lesions were both significantly higher as compared with control endometrium (P<0.05), and both positively correlated with pain (P<0.05). The expression levels of phosphorylated –ERK (p-ERK), phosphorylated-cAMP-response element binding protein (p-CREB), and P2X3 in endometriotic stromal cells (ESCs) were all significantly increased in comparison to the initial levels after treated with interleukin (IL)-1β (P<0.05) or adenosine triphosphate (ATP) (P<0.05), respectively, and did not increase after the ESCs were pre-treated with ERK1/2 inhibitor. Additionally, P2X3 and calcitonin gene related peptide (CGRP) were co-expressed in endometriotic lesions. These obtained results suggest that P2X3 might be involved in endometriosis pain signal transduction via ERK signal pathway.

The Clinical Significance of Endocannabinoids in Endometriosis Pain Management

Introduction: Patients with endometriosis often suffer from diffuse and poorly localized severe pain. The current pain management strategies include medical and hormonal therapy, as well as surgery. Medical management of pain is often insufficient and is associated with high rate of recurrence. Better pain management is therefore of urgent need. Methods: Among the various candidates, the endocannabinoid system (ECS) has recently emerged as a relevant pharmacological target for the management of endometriosis-related pain. A computerized literature search was performed to identify relevant studies combining the keywords "endometriosis," "endocannabinoid," "cannabinoid receptor," "THC," and "pain mechanisms." Conclusions: This review describes the multiple and complex pain mechanisms associated with endometriosis. Current data and theories concerning the link between the ECS and pain management for endometriosis patients are presented. Finally, we will discuss which aspects of endometriosis-associated pain can be targeted by modulation of the ECS.

Macrophage and nerve interaction in endometriosis

Dysregulation of the immune system in endometriotic milieus has been considered to play a pivotal role in the pathogenesis of endometriosis. Macrophage recruitment and nerve fiber infiltration are the two major characteristics of this aberrant immune environment. First, the recruitment of macrophages and their polarization phenotype within the endometriotic lesion have been demonstrated to facilitate the development and maintenance of endometriosis. M1 phenotype of macrophages has the capacity to secrete multiple cytokines for inflammatory response, while M2 macrophage possesses an opposite property that can mediate the process of immunosuppression and neuroangiogenesis. Upon secretion of multiple abnormal signal molecules by the endometriotic lesion, macrophages could alter their location and phenotype. These changes facilitate the accommodation of the aberrant microenvironment and the exacerbation of disease progression. Second, the infiltration of nerve fibers and their abnormal distribution are proved to be involved in the generation of endometriosis-associated pain and inflammatory response. An imbalance in sensory and sympathetic innervation and the abnormal secretion of different cytokines could mediate neurogenesis and subsequent peripheral neuroinflammation in endometriosis. Although endometriosis creates an inflammatory milieu promoting macrophage infiltration and an imbalanced innervation, interaction between macrophages and nerve fibers in this process remains unknown. The aim of this review is to highlight the role of macrophage and nerve interaction in endometriosis, where macrophage recruitment and neurogenesis can be the underlying mechanism of neuroinflammation and pathogenesis of endometriosis.

Potential scenarios leading to ovarian cancer arising from endometriosis

OBJECTIVES

The aim of this review was to highlight recent advances in our understanding of the pathogenesis of malignant transformation of endometriosis.

METHODS

This study reviewed the English-language literature concerning basic science studies of the potential promotion of carcinogenesis.

RESULTS

Repeated episodes of hemorrhage occur in endometriosis at the onset of menstruation. Extracellular hemoglobin, heme, and iron derivatives in endometriosis cause DNA damage and mutations, which create increased cellular susceptibility to oxidant-mediated cell killing. Excess DNA damage and mutations are linked to cell death, but not carcinogenesis. In response to an oxidative and inflammatory microenvironment, endometriotic cells and macrophages secrete antioxidants that control excess oxidative stress in the surrounding environment. Exposure of endometriotic cells to a sublethal level of oxidative stress may lead to carcinogenesis. Macrophages also secrete immunosuppressive factors that lead to promotion of malignant transformation.

DISCUSSION

At least two potential scenarios could result in ovarian cancer arising from endometriosis. The first step: extracellular hemoglobin, heme, and iron cause cellular oxidative damage by promoting reactive oxygen species formation, which results in DNA damage and mutations (ovarian cancer initiation from endometriosis). The second step: cancer progression may be associated with persistent antioxidant production favoring a protumoral microenvironment.