Expression of transforming growth factor β1 in nerve fibers is related to dysmenorrhea and laparoscopic appearance of endometriotic implants

Endometriosis-Related Chronic Pelvic Pain

Endometriosis, which is the presence of endometrial stroma and glands outside the uterus, is one of the most frequently diagnosed gynecologic diseases in reproductive women. Patients with endometriosis suffer from various pain symptoms such as dysmenorrhea, dyspareunia, and chronic pelvic pain. The pathophysiology for chronic pain in patients with endometriosis has not been fully understood. Altered inflammatory responses have been shown to contribute to pain symptoms. Increased secretion of cytokines, angiogenic factors, and nerve growth factors has been suggested to increase pain. Also, altered distribution of nerve fibers may also contribute to chronic pain. Aside from local contributing factors, sensitization of the nervous system is also important in understanding persistent pain in endometriosis. Peripheral sensitization as well as central sensitization have been identified in patients with endometriosis. These sensitizations of the nervous system can also explain increased incidence of comorbidities related to pain such as irritable bowel disease, bladder pain syndrome, and vulvodynia in patients with endometriosis. In conclusion, there are various possible mechanisms behind pain in patients with endometriosis, and understanding these mechanisms can help clinicians understand the nature of the pain symptoms and decide on treatments for endometriosis-related pain symptoms.

Mutual regulation between glycosylation and transforming growth factor-β isoforms signaling pathway

Transforming growth factor-beta (TGF-β) superfamily members orchestrate a wide breadth of biological processes. Through Sma and Mad (Smad)-related dependent or noncanonical pathways, TGF-β members involve in the occurrence and development of many diseases such as cancers, fibrosis, autoimmune diseases, cardiovascular diseases and brain diseases. Glycosylation is one kind of the most common posttranslational modifications on proteins or lipids. Abnormal protein glycosylation can lead to protein malfunction and biological process disorder, thereby causing serious diseases. Previously, researchers commonly make comprehensive systematic overviews on the roles of TGF-β signaling in a specific disease or biological process. In recent years, more and more evidences associate glycosylation modification with TGF-β signaling pathway, and we can no longer disengage and ignore the roles of glycosylation from TGF-β signaling to make investigation. In this review, we provide an overview of current findings involved in glycosylation within TGF-βs and theirs receptors, and the interaction effects between glycosylation and TGF-β subfamily signaling, concluding that there is an intricate mutual regulation between glycosylation and TGF-β signaling, hoping to present the glycosylation regulatory patterns that concealed in TGF-βs signaling pathways.

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.

Peripheral, Central, and Cross Sensitization in Endometriosis-Associated Pain and Comorbid Pain Syndromes

Endometriosis-associated pain and the mechanisms responsible for its initiation and persistence are complex and difficult to treat. Endometriosis-associated pain is experienced as dysmenorrhea, cyclical pain related to organ function including dysuria, dyschezia and dyspareunia, and persistent pelvic pain. Pain symptomatology correlates poorly with the extent of macroscopic disease. In addition to the local effects of disease, endometriosis-associated pain develops as a product of peripheral sensitization, central sensitization and cross sensitization. Endometriosis-associated pain is further contributed to by comorbid pain conditions, such as bladder pain syndrome, irritable bowel syndrome, abdomino-pelvic myalgia and vulvodynia. This article will review endometriosis-associated pain, its mechanisms, and its comorbid pain syndromes with a view to aiding the clinician in navigating the literature and terminology of pain and pain syndromes. Limitations of our current understanding of endometriosis-associated pain will be acknowledged. Where possible, commonalities in pain mechanisms between endometriosis-associated pain and comorbid pain syndromes will be highlighted.

Assessment of Nerve Fiber Density and Expression of Hormonal Receptors Within Rectosigmoid Endometriosis Nodules

STUDY OBJECTIVE

To assess nerve fiber density and expression of hormone receptors in bowel endometriosis.

DESIGN

Cross-sectional study.

SETTING

Private hospital.

PATIENTS

Women with endometriosis undergoing laparoscopic segmental bowel resection (n = 54).

INTERVENTIONS

Tissue samples were obtained from patients with surgically treated rectosigmoid endometriosis.

MEASUREMENTS AND MAIN RESULTS

The rectosigmoid specimen containing the endometriosis nodule was manually sectioned and divided into 3 areas: core of the nodule, margin of the nodule, and healthy bowel tissue. The intensity of expression of estrogen and progesterone receptors was evaluated by immunohistochemistry and measured according to the Allred score. Nerve fibers were stained by immunohistochemistry using Protein Gene Product 9.5, and the density of nerve fillets was counted and expressed in number/mm². All glandular and stromal cells stained for estrogen; however, glandular cells stained more strongly than stromal cells (61.1% vs 35.2%; p = .01). Most of glandular and stromal cells stained strongly for progesterone receptors (90.7% vs 98.1%; p = .2). The density of nerve fibers was very high in the margin of the nodule (172.22±45.66/mm²), moderate in healthy bowel tissue (111.48±48.57/mm²), and very low in the core of the nodule (7.31±4.9/mm²); p = .01.

CONCLUSION

Both glandular and stromal cells within the rectosigmoid endometriosis nodule express estrogen and progesterone receptors. Higher intensity of expression of estrogen receptors occurs in glandular cells. The density of nerve fibers is extremely high at the nodule margin and very low in the center of the nodule.

Elevated peritoneal soluble endoglin and GDF-15 in infertile women with severe endometriosis and pelvic adhesion

OBJECTIVES

Chronic inflammation and pelvic adhesion play a critical role in endometriosis-related infertility. Research studies suggest that TGF-β superfamily members, such as soluble endoglin (sEng), growth differentiation factor 15 (GDF-15) and tumor growth factor-beta (TGF-β1) contribute to the regulation of inflammation, angiogenesis and cell adhesion. The objective of this study is to investigate the association between the concentrations of these TGF-β-related members and the clinical parameters of infertile women with endometriosis.

MATERIALS AND METHODS

Sixty-five infertile women who underwent laparoscopy were divided into two groups in this study: those who had endometriosis (n = 33) and control subjects with benign gynecologic disorders (n = 32). The levels of TGF-β- related members in peritoneal fluid and serum were evaluated by the enzyme-linked immunosorbent assay (ELISA). Clinical and hematological parameters were documented and analyzed.

RESULTS

Endometriosis cases had significantly higher levels of sEng, GDF-15 and TGF-β1 in peritoneal fluid (p<0.0005) compared to control subjects, but not in serum. Moreover, serum GDF-15 level was significantly elevated in the late-stage endometriosis compared to the early-stage group. The levels of three TGF-β related molecules in peritoneal fluid showed positive correlations with rASRM score. Blood neutrophil counts have correlation with the peritoneal sEng concentration.

CONCLUSION

Our novel evidence on the elevated concentration of peritoneal sEng and GDF-15 in endometriosis, specifically in the late-stage, may indicate the essential role of TGF-β-dependent signaling in endometriosis. Serum GDF-15 might serve as a candidate biomarker for endometriosis severity. Further studies are warranted to investigate the role and regulation of these molecules in endometriosis.

Relationship between Cyst Fluid Concentrations of Iron and Severity of Dysmenorrhea in Patients with Ovarian Endometrioma

OBJECTIVES AND DESIGN

Endometriosis-related pain can be caused by anatomical distortions as well as environmental factors such as inflammation and oxidative stress. The aim of this study is to investigate the relationship between the severity of dysmenorrhea in patients with ovarian endometrioma (OMA) and cyst fluid (CF) concentrations of irons, including total iron, heme iron, and free iron.

METHOD

Eighty-three patients who were histologically diagnosed with OMA were enrolled in the Department of Gynecology, Nara Medical University Hospital, between 2013 and 2019. The patients were divided into 4 groups according to the severity of dysmenorrhea: no pain, mild, moderate, and severe. Iron concentration was measured by the inductively coupled plasma optical emission spectrometry method.

RESULTS

There were no significant differences among the 4 groups in variables such as age at diagnosis, preoperative CA125, preoperative CA19-9, cyst size, and tumor laterality (unilateral or bilateral). There was a positive correlation between the severity of dysmenorrhea and total iron (p < 0.001) and heme iron (p = 0.016) concentrations. Multiple regression analyses revealed that the CF concentration of total iron (hazard ratio 18.75, 95% confidence interval: 2.26-155.35, p = 0.007) was a significant independent variable associated with the severity of dysmenorrhea. A receiver operating characteristic curve analysis showed that a total iron exceeding 290.8 mg/L was associated with severe dysmenorrhea with a sensitivity of 90.9% and a specificity of 65.7%.

LIMITATIONS

This study excluded patients with adenomyosis, superficial endometriosis, or deep endometriosis, resulting in a smaller number of cases. Iron levels could not be compared to the endometriosis stage using the r-ASRM score.

CONCLUSIONS

There is no clear evidence that iron predicts the severity of endometriosis-related pain. However, iron may be closely associated with dysmenorrhea.

Endometriosis-Associated Pain - Do Preclinical Rodent Models Provide a Good Platform for Translation?

Pelvic pain is a common symptom of endometriosis. Our understanding of its etiology remains incomplete and medical management is limited by poor translation from preclinical models to clinical trials. In this review, we briefly consider the evidence, or lack thereof, that different subtypes of lesion, extra-uterine bleeding, and neuropathic pathways add to the complex and heterogeneous pain experience of women with the condition. We summarize the studies in rodent models of endometriosis that have used behavioral endpoints (evoked and non-evoked) to explore mechanisms of endometriosis-associated pain. Lesion innervation, activation of nerves by pronociceptive molecules released by immune cells, and a role for estrogen in modulating hyperalgesia are key endometriosis-associated pain mechanisms replicated in preclinical rodent models. The presence of ectopic (full thickness uterus or endometrial) tissue may be associated with changes in the spinal cord and brain, which appear to model changes reported in patients. While preclinical models using rats and mice have yielded insights that appear relevant to mechanisms responsible for the development of endometriosis-associated pain, they are limited in scope. Specifically, most studies are based on models that only resulted in the formation of superficial lesions and use induced (evoked) behavioral 'pain' tests. We suggest that translation for patient benefit will be improved by new approaches including models of ovarian and deep infiltrating disease and measurement of spontaneous pain behaviors. Future studies must also capitalize on new advances in the wider field of pain medicine to identify more effective treatments for endometriosis-associated pain.

Endometrial biopsy and density of nerve fibers in eutopic endometrium. Looking for easier ways to diagnose endometriosis

The purpose of study was to evaluate if there is any difference between nerve fibers density in eutopic endometrium in women with and without endometriosis. The prospective case - control study conducted between October 2013 and December 2015. The study included 60 reproductive age women undergoing laparoscopy for suspected endometriosis, pelvic pain, or infertility and not currently receiving hormonal treatment for at least 3 months prior to laparoscopy. Immunohistochemical nerve fiber detection in endometrial curetting using anti-gene product 9.5 was compared with surgical diagnosis. The nerve fibers were detected in eutopic endometrium in women with and without endometriosis. PGP9.5 positive nerve fibers were found in 26 (43%) cases: 16 (50%) in women with endometriosis and 10 (36%) in women without endometriosis. The mean nerve fiber density was higher in the group with endometriosis (0.53 per mm² ± 0.68) than without endometriosis (0.48 per mm² ± 0.89), but no statistically significant difference was observed (p > .05). Test specificity was 64.3%, sensitivity 50%, positive predictive value - 61.5%, negative predictive value - 52.9%, and overall accuracy 56.7%. The detection of PGP9.5 positive nerve fibers in eutopic endometrium cannot be used as a reliable diagnostic test of diagnosing endometriosis.

Cellular Components Contributing to Fibrosis in Endometriosis: A Literature Review

Endometriosis-related fibrosis represents a complex phenomenon with underlying mechanisms yet to be clarified. Fibrosis is consistently present in all disease forms and contributes to classic endometriosis-related symptoms of pain and infertility. The purpose of this literature review was to examine the role of various cellular populations and biologic mechanisms and signaling pathways in inducing fibrogenesis of endometriotic lesions. A search was performed through PubMed and MEDLINE for animal and human studies published in English in the last 23 years that examined fibrosis in superficial, ovarian, and deep infiltrating endometriosis. The main cell types found to be involved in the development of fibrosis were platelets, macrophages, ectopic endometrial cells, and sensory nerve fibers. Interactions among each of the cell types contribute to the production of fibrosis through the production of soluble factors, mostly transforming growth factor-β but also other cytokines and neuropeptides. Cell types known to be critical to the pathophysiology of endometriosis also contribute to fibrogenesis, thus supporting the theory that fibrosis is an inherent part of endometriosis.

Endometriotic lesions

Endometriosis is a complex gynaecological condition affecting women of reproductive age. It is characterised by the presence of lesions containing endometrial glands and stroma outside the uterus. The disease is typically associated with pelvic pain (including dysmenorrhoea and dyspareunia), infertility and bowel-related symptoms. Endometriotic lesions have a highly variable presentation and most commonly occur in the abdominal cavity. These lesions are broadly classified into peritoneal, ovarian and deep infiltrating endometriosis. There have been observations of increased density of nerve fibres and neurological molecules in the endometriotic lesions compared to the uninvolved peritoneum of women without endometriosis and the presence of unmyelinated nerve fibres were higher near the glands. The lesion sites are characterised by a range of immunological alterations, and specific immune cell populations have also been known to synthesise and secrete neurogenic factors. Endometriotic lesions are capable of producing prostaglandins which are direct generators of pain and are capable of inducing inflammation. Diagnosing the disease involves direct visualisation of the lesions through a laparoscopic or laparotomy, which is followed by histopathological examination of biopsied or excised lesions. The staging of endometriosis due to its complexity is highly variable as presentation and gaps in knowledge pose a great challenge in the classification of the disease. The medical management of endometriosis aims at providing adequate analgesia and suppression of the activity of the lesion. A better understanding of endometriotic lesion relationships between innervations and specific clinical characteristics may elucidate aspects of pain mechanisms and infertility in endometriosis and facilitate the development of novel therapeutic approaches.

Nerve fibre infiltration and expression in peritoneal lesions of endometriosis in a nonhuman primate model of endometriosis

Baboon ( Papio anubis) models of endometriosis are thought to mimic the early stages of spontaneous human peritoneal endometriotic disease. The objective of this study was to investigate the presence and course of nerve fibre ingrowth during peritoneal lesion formation in specimens collected at 3 months (early stage of lesion development) and 15 months (late stage of lesion development) after disease initiation compared to pelvic peritoneum (control). Five-micron sections of paraffin-embedded peritoneal lesions were obtained from normally cycling baboons with 3-month (n = 12), 15-month (n = 12) induced endometriosis and pelvic peritoneum (n = 10) from baboons with no endometriosis. Immunohistochemical staining was performed with specific antibodies: protein gene product 9.5 – broad marker of nerve fibres and neurones, neuropeptide Y – sympathetic neurones, substance P – sensory neurones, vasoactive intestinal peptide – parasympathetic neurones, nerve growth factor – development of new neurones and high-affinity receptor for nerve growth factor (tropomyosin receptor kinase A) – neuronal differential. Significantly, more nerve fibres were identified in peritoneal endometriotic lesions collected 15 months after the initiation of experimental protocols compared with 3-month and control samples (p < 0.001). Nerve fibres were immunoreactive for all the tested markers – protein gene product 9.5, neuropeptide Y, substance P, vasoactive intestinal peptide, nerve growth factor and tropomyosin receptor kinase A – indicating the presence of different types of nerve fibres. In conclusion, peritoneal lesions of endometriosis in a nonhuman primate model of endometriosis were found to be progressively and spontaneously innervated by both myelinated and unmyelinated sensory nerve fibres, parasympathetic and sympathetic neurones. These nerve fibres may play an important role in the mechanisms of pain generation in this condition.

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”.

Effects of cisplatin on surgically induced endometriosis in a rat model

Research has strongly suggested that the features of endometriosis serve as a precursor lesion of ovarian cancer. Cisplatin (CDDP) is the preferred drug against these cancer types. The present study investigated the effects of CDDP on surgically induced endometriosis in a rat model. Endometriosis was surgically induced by the autologous transplantation of endometrial tissue. A total of 36 model rats were randomly divided into three groups. The rats in Group 1 (control group, n=12) received no medication. The rats in Group 2 (n=12) and Group 3 (n=12) were administered 35 mg/m² CDDP and 70 mg/m² CDDP, respectively, every four days. All rats were treated for a total of 24 days. The growth and histologic scores of the implants were calculated. The expression of protein markers, including vascular endothelial growth factor (VEGF), aromatase P450 (P450arom), transforming growth factor-β (TGF-β) and matrix metalloproteinase (MMP)-2, were assessed using immunohistochemistry, an enzyme-linked immunosorbent assay and western blot analysis. Following CDDP treatment, the mean implant sizes were significantly reduced in Groups 2 and 3 compared with the control group (P=0.01). The mean histologic scores were also significantly lower in Groups 2 and 3. Furthermore, the protein expression of VEGF, P450arom, TGF-β and MMP-2 was significantly lower in Groups 2 and 3 when compared with the control group. A loss of hair was observed in 4 rats, which only occurred in Group 3. A dose-dependent effect was observed in the two CDDP-treated groups. In conclusion, the expression of proliferation- and angiogenesis-associated proteins was significantly lower following treatment with CDDP. CDDP caused a significant regression in the size of the endometriotic implants and induced atrophy of these lesions in rats.

The role of TGF-β in the pathophysiology of peritoneal endometriosis

BACKGROUND

Endometriosis is estimated to affect 6-10% of women of reproductive age and it is associated with chronic pelvic pain, dysmenorrhoea and subfertility. It is currently managed surgically or medically but symptoms recur in up to 75% of cases and available medical treatments have undesirable side effects. Endometriosis is defined as the presence of endometrial tissue outside the uterus with lesions typically found on the peritoneum. The aetiology of endometriosis is uncertain but there is increasing evidence that transforming growth factor (TGF)-β plays a major role.

OBJECTIVE AND RATIONALE

A descriptive review was undertaken of the published literature on the expression pattern of TGF-β ligands and signalling molecules in women with and without endometriosis, and on the potential roles of TGF-β signalling in the development and progression of peritoneal endometriosis. The current understanding of the TGF-β signalling pathway is summarized.

SEARCH METHODS

We searched the Pubmed database using the terms 'transforming growth factor beta' and 'endometriosis' for studies published between 1995 and 2016. The initial search identified 99 studies and these were used as the basic material for this review. We also extended our remit for important older publications. In addition, we searched the reference lists of studies used in this review for additional studies we judged as relevant. Studies which were included in the review focused on peritoneal endometriosis only as increasing evidence suggests that ovarian and deep endometriosis may have a differing pathophysiology. Thus, a final 95 studies were included in the review.

OUTCOMES

TGF-β1 is reported to be increased in the peritoneal fluid, serum, ectopic endometrium and peritoneum of women with endometriosis compared to women without endometriosis, and TGF-β1-null mice have reduced endometriosis lesion growth when compared to their wild-type controls. Studies in mice and women have indicated that increasing levels of TGF-β ligands are associated with decreased immune cell activity within the peritoneum, together with an increase in ectopic endometrial cell survival, attachment, invasion and proliferation, during endometriosis lesion development. TGF-β1 has been associated with changes in ectopic endometrial and peritoneal cell metabolism and the initiation of neoangiogenesis, further fuelling endometriosis lesion development.

WIDER IMPLICATIONS

Together these studies suggest that TGF-β1 plays a major role in the development of peritoneal endometriosis lesions and that targeting this pathway may be of therapeutic potential.

Endometriosis-associated Pain in Patients with and without Hormone Therapy

Introduction

Endometriosis is associated with both cyclic and non-cyclic pelvic pain. Many patients do not remain symptom free, even after guideline-oriented treatment. This study aimed to identify differences in endometriosis-associated pain and test for possible associations with hormone therapy.

Methods

The results presented here are based on a cross-sectional study conducted at the Charité Endometriosis Center in Berlin in which pain profile data were collected via a questionnaire from women with a confirmed diagnosis of endometriosis. The questionnaire contained items concerning cyclic and non-cyclic pain, pain intensity, and pain duration. SPSS software was used to perform the statistical analysis, including descriptive and analytical statistics.

Results

Of 239 women surveyed, 121 (50.6%) reported current hormone therapy, and 185 (77.4%) reported previous hormone therapy. Moreover, 84% had current (cyclic and non-cyclic) pain symptoms, which were severe enough to warrant treatment in nearly 70% of all cases. Hormone therapy was only found to be associated with a slight, non-significant advantage in patients with “cyclic pain”. The reverse was true of non-cyclic pain: women on hormone therapy reported a greater incidence of pain, greater pain intensity, more frequent need for treatment, and more pain days.

Conclusions

With a very broad interpretation of our findings, it can be concluded that hormone therapy achieves some degree of pain reduction via down-regulation of the ovarian cycle, at least in the case of cyclic pain, whereas non-cyclic pain does not respond or no longer responds to hormones.

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

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

The importance of pelvic nerve fibers in endometriosis

Several lines of recent evidence suggest that pelvic innervation is altered in endometriosis-affected women, and there is a strong presumption that nerve fibers demonstrated in eutopic endometrium (of women with endometriosis) and in endometriotic lesions play roles in the generation of chronic pelvic pain. The recent observation of sensory C, sensory A-delta, sympathetic and parasympathetic nerve fibers in the functional layer of endometrium of most women affected by endometriosis, but not demonstrated in most women who do not have endometriosis, was a surprise. Nerve fiber densities were also greatly increased in myometrium of women with endometriosis and in endometriotic lesions compared with normal peritoneum. Chronic pelvic pain is complex, and endometriosis is only one condition which contributes to this pain. The relationship between the presence of certain nerve fibers and the potential for local pain generation requires much future research. This paper reviews current knowledge concerning nerve fibers in endometrium, myometrium and endometriotic lesions, and discusses avenues of research that may improve our knowledge and lead to enriched understanding and management of endometriotic pain symptoms.

Update on Biomarkers for the Detection of Endometriosis

Endometriosis is histologically characterized by the displacement of endometrial tissue to extrauterine locations including the pelvic peritoneum, ovaries, and bowel. An important cause of infertility and pelvic pain, the individual and global socioeconomic burden of endometriosis is significant. Laparoscopy remains the gold standard for the diagnosis of the condition. However, the invasive nature of surgery, coupled with the lack of a laboratory biomarker for the disease, results in a mean latency of 7–11 years from onset of symptoms to definitive diagnosis. Unfortunately, the delay in diagnosis may have significant consequences in terms of disease progression. The discovery of a sufficiently sensitive and specific biomarker for the nonsurgical detection of endometriosis promises earlier diagnosis and prevention of deleterious sequelae and represents a clear research priority. In this review, we describe and discuss the current status of biomarkers of endometriosis in plasma, urine, and endometrium.

Effect of human umbilical cord mesenchymal stem cells transplantation on nerve fibers of a rat model of endometriosis

Background

Endometriosis is a common, benign, oestrogen-dependent, chronic gynaecological disorder associated with pelvic pain and infertility. Some researchers have identified nerve fibers in endometriotic lesions in women with endometriosis. Mesenchymal stem cells (MSCs) have attracted interest for their possible use for both cell and gene therapies because of their capacity for self-renewal and multipotentiality of differentiation. We investigated how human umbilical cord-MSCs (hUC-MSCs) could affect nerve fibers density in endometriosis.

Materials and Methods

In this experimental study, hUC-MSCs were isolated from fresh human umbilical cord, characterized by flow cytometry, and then transplanted into surgically induced endometriosis in a rat model. Ectopic endometrial implants were collected four weeks later. The specimens were sectioned and stained immunohistochemically with antibodies against neurofilament (NF), nerve growth factor (NGF), NGF receptor p75 (NGFRp75), tyrosine kinase receptor-A (Trk-A), calcitonin gene-related peptide (CGRP) and substance P (SP) to compare the presence of different types of nerve fibers between the treatment group with the transplantation of hUC-MSCs and the control group without the transplantation of hUC-MSCs.

Results

There were significantly less nerve fibers stained with specific markers we used in the treatment group than in the control group (p<0.05).

Conclusion

MSC from human umbilical cord reduced nerve fiber density in the treatment group with the transplantation of hUC-MSCs.

Innervation in women with uterine myoma and adenomyosis

Objective

To determine if neurofilament (NF) is expressed in the endometrium and the lesions of myomas and adenomyosis, and to determine their correlation.

Methods

Histologic sections were prepared from hysterectomies performed on women with adenomyosis (n=21), uterine myoma (n=31), and carcinoma in situ of the uterine cervix. Full-thickness uterine paraffin blocks, which included the endometrium and myometrium histologic sections, were stained immunohistochemically using the antibodies for monoclonal mouse antihuman NF protein.

Results

NF-positive cells were found in the endometrium and myometrium in 11 women with myoma and in 7 with adenomyosis, but not in patients with carcinoma in situ of uterine cervix, although the difference was statistically not significant. There was no significant difference between the existence of NF-positive cells and menstrual pain or phases. The NF-positive nerve fibers were in direct contact with the lesions in nine cases (29.0%) of myoma and in five cases (23.8%) of adenomyosis. It was analyzed if there was a statistical significance between the existence of NF positive cells in the endometrium and the expression of NF-positive cells in the uterine myoma/adenomyosis lesions. When NF-positive cell were detected in the myoma lesions, the incidence of NF-positive nerve cells in the eutopic endometrium was significantly high. When NF-positive cell were detected in the basal layer, the incidence of NF-positive nerve cells in the myoma lesions and adenomyosis lesions was significantly high.

Conclusion

We assume that NF-positive cells in the endometrium and the myoma and adenomyosis lesions might play a role in pathogenesis. Therefore, more studies may be needed on the mechanisms of nerve fiber growth in estrogen-dependent diseases.

Peripheral changes in endometriosis-associated pain

BACKGROUND

Pain remains the cardinal symptom of endometriosis. However, to date, the underlying mechanisms are still only poorly understood. Increasing evidence points towards a close interaction between peripheral nerves, the peritoneal environment and the central nervous system in pain generation and processing. Recently, studies demonstrating nerve fibres and neurotrophic and angiogenic factors in endometriotic lesions and their vicinity have led to increased interest in peripheral changes in endometriosis-associated pain. This review focuses on the origin and function of these nerves and factors as well as possible peripheral mechanisms that may contribute to the generation and modulation of pain in women with endometriosis.

METHODS

We conducted a systematic search using several databases (PubMed, MEDLINE, EMBASE and CINAHL) of publications from January 1977 to October 2013 to evaluate the possible roles of the peripheral nervous system in endometriosis pathophysiology and how it can contribute to endometriosis-associated pain.

RESULTS

Endometriotic lesions and peritoneal fluid from women with endometriosis had pronounced neuroangiogenic properties with increased expression of new nerve fibres, a shift in the distribution of sensory and autonomic fibres in some locations, and up-regulation of several neurotrophins. In women suffering from deep infiltrating endometriosis and bowel endometriosis, in which the anatomical distribution of lesions is generally more closely related to pelvic pain symptoms, endometriotic lesions and surrounding tissues present higher nerve fibre densities compared with peritoneal lesions and endometriomas. More data are needed to fully confirm a direct correlation between fibre density in these locations and the amount of perceived pain. A better correlation between the presence of nerve fibres and pain symptoms seems to exist for eutopic endometrium. However, this appears not to be exclusive to endometriosis. No correlation between elevated neurotrophin levels and pain severity appears to exist, suggesting the involvement of other mediators in the modulation of pain.

CONCLUSIONS

The increased expression of neurotrophic factors and nerve fibres in endometriotic lesions, eutopic endometrium and the peritoneum imply a role of such peripheral changes in the pathogenesis of endometriosis-associated pain. However, a clear link between these findings and pain in patients with endometriosis has so far not been demonstrated.

Effect of siRNA against β-NGF on nerve fibers of a rat model with endometriosis

OBJECTIVE

This study examines whether silencing specific β-nerve growth factor small interfering RNA (β-NGF siRNA) can affect the growth of ectopic endometriotic implants, generalized hyperalgesia, and nerve fiber density in endometriosis.

METHODS

Four specific β-NGF siRNAs were detected by Western blot analysis, and the most efficient specific siRNA was transferred into rats with surgically induced endometriosis through gene transfer. The length × width × height of each ectopic transplant that survived from 2 groups were measured at pre-and postbombardment after 2 weeks. The transplants were collected 2 weeks after bombardment. Warm-water tail flick test was performed before the rats were sacrificed. The specimens were sectioned and stained immunohistochemically with antibodies against the types of nerve fibers to compare the presence of different nerve fibers in the treatment and control groups. The serums and supernatants of the peritoneal washings in the treatment and control groups were collected for enzyme-linked immunosorbent assay (ELISA) analysis. The extra rats were successfully induced with endometriosis and through gene transfer as described above. The spherical volumes of the transplants and tail flick latency post-bombardment after 4, 6, 8, and 10 weeks were measured.

RESULTS

The spherical volumes in the treatment group were much smaller than those in the control group, and tail flick latency significantly increased in the treatment group postbombardment after 2 weeks. The ELISA analysis showed that the concentrations of β-NGF in the serums and supernatants of the peritoneal fluid decreased in the treatment group unlike in the control group. Less sympathetic and sensory innervation was observed in the treatment group postbombardment after 2 weeks. The outcomes of the spherical volumes of the transplants and tail flick latency postbombardment after 4, 6, 8, and 10 weeks showed that the sizes of the transplants did not return to their previous size and that the treatment had some effects on generalized hyperalgesia.

CONCLUSION

Specific siRNA-mediated silencing of the β-NGF gene expression after gene transfer suppressed the growth of ectopic endometriotic implants resulted in a significant improvement in generalized hyperalgesia as well as reduced sympathetic and sensory nerve fiber density in the treatment group.

Association between TGF-β1-509C/T polymorphism and endometriosis: a systematic review and meta-analysis

OBJECTIVE

To evaluate the association between the transforming growth factor β1 gene-509C/T (TGF-β1-509C/T) polymorphism and the risk of endometriosis.

STUDY DESIGN

Relevant studies published before October 2011 were identified by searching PubMed and Embase. Studies were selected using prior defined criteria. The strength of the relationship between the TGF-β1-509C/T polymorphism and endometriosis risk was assessed by Odds Ratios (ORs). Fixed- or random-effects model was calculated according to study heterogeneity. Stratification analysis and sensitivity analysis were also conducted. Possible publication bias was tested by funnel plots and Egger's test.

RESULTS

Of 49 potentially relevant studies, six case-control studies were identified in this meta-analysis. The integrated result showed that the TGF-β1-509C/T polymorphism was not associated with the endometriosis risk for the allele contrast (T vs. C: OR=1.57, 95%CI=0.88-2.79), the additive genetic model (T/T vs. C/C: OR=2.96, 95%CI=0.97-9.10), the dominant genetic model (T/T+T/C vs. C/C: OR=1.80, 95%CI=0.80-4.07) and the recessive genetic model (T/T vs. C/C+T/C: OR=1.91, 95%CI=0.89-4.12). In the stratified analysis by ethnicity, genotyping method and source of control, no significantly association was found. Publication bias was not detected in the included studies.

CONCLUSIONS

Meta-analyses of the available data showed that the association between TGF-β1-509C/T polymorphism and susceptibility of endometriosis was not significant. More studies are needed to elucidate its role in endometriosis.

Endometriosis: the role of neuroangiogenesis

Endometriosis is a common cause of pelvic pain and infertility, affecting ∼10% of reproductive-age women. Annual costs for medical and surgical care in the United States exceed $20 billion. The disorder is characterized by implants of endometrial tissue outside the uterine cavity. Endometriotic lesions induce a state of chronic peritoneal inflammation, accompanied by elevated prostaglandin, cytokine, and growth factor concentrations. The current therapy is surgical ablation of ectopic implants and hormones that block the hypothalamic-pituitary-ovarian axis, but these approaches are expensive, carry perioperative risks, or have unpleasant side effects of hypoestrogenism. Recent evidence indicates that ectopic endometriotic implants recruit their own unique neural and vascular supplies through neuroangiogenesis. It is believed that these nascent nerve fibers in endometriosis implants influence dorsal root neurons within the central nervous system, increasing pain perception in patients. We consider the mechanisms and therapeutic implications of neuroangiogenesis in these lesions and propose potential treatments for the control or elimination of endometriosis-associated pain.

Chronic pelvic pain and endometriosis: translational evidence of the relationship and implications

BACKGROUND

Many clinicians and patients believe that endometriosis-associated pain is due to the lesions. Yet causality remains an enigma, because pain symptoms attributed to endometriosis occur in women without endometriosis and because pain symptoms and severity correlate poorly with lesion characteristics. Most research and reviews focus on the lesions, not the pain. This review starts with the recognition that the experience of pain is determined by the central nervous system (CNS) and focuses on the pain symptoms.

METHODS

Comprehensive searches of Pubmed, Medline and Embase were conducted for current basic and clinical research on chronic pelvic pain and endometriosis. The information was mutually interpreted by a basic scientist and a clinical researcher, both in the field of endometriosis. The goal was to develop new ways to conceptualize how endometriosis contributes to pain symptoms in the context of current treatments and the reproductive tract.

RESULTS

Endometriotic lesions can develop their own nerve supply, thereby creating a direct and two-way interaction between lesions and the CNS. This engagement provides a mechanism by which the dynamic and hormonally responsive nervous system is brought directly into play to produce a variety of individual differences in pain that can, in some women, become independent of the disease itself.

CONCLUSIONS

Major advances in improving understanding and alleviating pain in endometriosis will likely occur if the focus changes from lesions to pain. In turn, how endometriosis affects the CNS would be best examined in the context of mechanisms underlying other chronic pain conditions.

Effect of peritoneal fluid from endometriosis patients on neuroblastoma cells in culture

AIM

Endometriosis is often associated with lower abdominal pain, dysmenorrhea, dyspareunia, and chronic pelvic pain. There is no correlation between the extent of endometriosis and the intensity of pain. The mechanism of pain in endometriosis is unknown. The aim of our study was to investigate the influence of peritoneal fluid (PF) from endometriosis patients on cultured neural cells that are the morphological basis of nociception, and to determine whether there was a relationship between the rAFS staging and an elevation of TGF-beta1 production by these cells.

METHODS

Different human neuroblastoma cell lines were grown to 3/4 confluence and then cultured in presence of PF pooled according to the presence of no, mild, or severe endometriosis. After 6 and 24 h of incubation, the morphological changes were assessed and the metabolic activity was determined.

RESULTS

The different cell lines showed strongly varying proliferation and aggregation patterns. The metabolic activity was also varying between cell lines, but no consistently increased cell turnover in the PF when compared with the control medium nor associated to a particular, endometriosis-derived PF pool could be shown. In this experimental setting, we have observed that the cell proliferation in the presence of PF was inhibited, and not enhanced as it might have been expected. Measurement of TGF-beta1 showed higher production rates for this cytokine under exposure to PF than in controls for some but not all tested cell lines, but there was no association with the stage (rAFS) of the disease.

CONCLUSION

The neuronal cell culture model may become a useful tool to investigate the endometriosis-derived pain, but different endpoints and cell lines may have to be introduced.

Dysmenorrhea: risk factors in women with endometriosis

Although it is generally accepted that endometriosis is responsible for dysmenorrhea, as well as other symptoms such as infertility, the precise relationship between the severity of dysmenorrhea and various characteristics of disease, such as stage and the type or site of endometriotic lesions, has been elusive and often a matter of heated debate, owing largely to conflicting reports. Here we review factors that are reported to be associated with dysmenorrhea in endometriosis. We also demonstrate, through a real example, that different statistical models employed in data analyses may yield somewhat different sets of risk factors, and the difference may not be always resolved within the same data set. In addition, we make the point that despite the best-fitting models, there may still be a sizable portion of variation in the severity of dysmenorrhea that can not be explained completely by the identified risk factors, suggesting that factors other than those of surgical findings or patient characteristics may also be responsible for dysmenorrhea severity. We review some possible factors that may also be responsible for the risk and severity of dysmenorrhea. Finally, we expose areas in need of further research.

Rich innervation of deep infiltrating endometriosis

BACKGROUND

Deep infiltrating endometriosis (DIE) is a specific type of endometriosis, which can be associated with more severe pelvic pain than other forms of endometriotic lesions. However, the mechanisms by which pain is generated are not well understood.

METHODS

DIE (n = 31) and peritoneal endometriotic (n = 40) lesions were sectioned and stained immunohistochemically with antibodies against protein gene product 9.5, neurofilament, nerve growth factor (NGF), NGF receptors tyrosine kinase receptor-A (Trk-A) and p75, substance P, calcitonin gene-related peptide, vesicular acetylcholine transporter, neuropeptide Y, vasoactive intestinal peptide and tyrosine hydroxylase to demonstrate myelinated, unmyelinated, sensory and autonomic nerve fibres.

RESULTS

There were significantly more nerve fibres in DIE (67.6 +/- 65.1/mm(2)) than in peritoneal endometriotic lesions (16.3 +/- 10.0/mm(2)) (P < 0.01). DIE was innervated abundantly by sensory Adelta, sensory C, cholinergic and adrenergic nerve fibres; NGF, Trk-A and p75 were strongly expressed in endometriotic glands and stroma of DIE.

CONCLUSIONS

The rich innervation of DIE may help to explain why patients with this type of lesion have severe pelvic pain.

The role of iron in the pathogenesis of endometriosis

BACKGROUND

Endometriosis may cause symptoms including chronic pelvic pain and infertility, and increases susceptibility to the development of ovarian cancer. Genomic studies have started to delineate the wide array of mediators involved in the development of endometriosis. Understanding the mechanisms of endometriosis development and elucidating its pathogenesis and pathophysiology are intrinsic to prevention and the search for effective therapies.

METHOD OF STUDY

The present article reviews the English language literature for biological, pathogenetic and pathophysiological studies on endometriosis. Several recent genomic studies are discussed in the context of endometriosis biology.

RESULTS

Severe hemolysis occurring during the development of endometriosis results in high levels of free heme and iron. These compounds oxidatively modify lipids and proteins, leading to cell and DNA damage, and subsequently fibrosis development. Recent studies based on genome-wide expression analysis technology have noted specific expression of heme/iron-dependent mediators in endometriosis. The heme/iron-dependent signaling pathway of endometriosis, which is providing new insights into the regulation of inflammation, detoxification and survival, is discussed.

CONCLUSION

Several important endometriosis-specific genes overlap with those known to be regulated by iron. Other genes are involved in oxidative stress. Iron has a significant impact on endometriotic-cell gene expression. This review summarizes recent advances in the heme/iron-mediated signaling and its target genes, outlines the potential challenges to understanding of the pathogenesis and pathophysiology of endometriosis, and proposes a possible novel model.

A pilot study to evaluate the clinical relevance of endometriosis-associated nerve fibers in peritoneal endometriotic lesions

OBJECTIVE

To investigate the clinical relevance of endometriosis-associated nerve fibers in the development of endometriosis-associated symptoms.

DESIGN

Prospective nonrandomized study.

SETTING

University hospital endometriosis center.

PATIENT(S)

Fifty-one premenopausal patients underwent surgical laparoscopy because of chronic pelvic pain, dysmenorrhea, or for ovarian cysts. Endometriosis was diagnosed in 44 patients.

INTERVENTION(S)

The preoperative and postoperative pain scores were determined using a standardized questionnaire with a visual analogue scale from 1-10. Patients with peritoneal endometriosis were divided into two groups depending on their preoperative pain score: group A with a pain score of at least 3 or more and group B with a pain score of 2 or less. Patients without peritoneal endometriosis were classified as group C and patients without endometriosis were classified as group D. Immunohistochemical analysis of neurofilament and protein gene product 9.5 were used for nerve fiber detection. Occurrence of endometriosis-associated nerve fibers was correlated with the severity of pelvic pain and/or dysmenorrhea.

RESULT(S)

Peritoneal endometriosis-associated nerve fibers were found significantly more frequently in group A than in group B (82.6% vs. 33.3%).

CONCLUSION(S)

The present study suggests that the presence of endometriosis-associated nerve fibers in the peritoneum is important for the development of endometriosis-associated pelvic pain and dysmenorrhea.

Gene expression profiling of the rat endometriosis model

PROBLEM

To investigate the molecular mechanism of endometriosis, gene expression profiling was analyzed in a rat endometriosis model.

METHOD OF STUDY

An endometriosis model was induced by uterine autotransplantation in the peritoneal cavity on a female-SD rat (8 weeks old). As control samples, the normal uterine tissues were used. The gene expression was compared between endometriotic lesions and normal uterine tissues by cDNA microarray analysis, quantitative real time RT-PCR and immunohistochemistry.

RESULTS

The expression of 71 genes was upregulated and that of 45 genes was downregulated in the endometriotic lesions compared to normal uterine tissues. The upregulated genes included genes encoding cytokines, chemokines, growth factors and cell adhesion molecules. The levels of transcripts of osteopontin, Lyn, Vav1, Runx1, and l-selectin in the endometriotic lesions were 130, 10, 10, 12 and 46-fold higher than the respective levels in the eutopic endometrial samples.

CONCLUSION

The results suggest that osteopontin, Lyn, Vav1, Runx1, and l-selectin play important roles in the pathogenesis of endometriosis.

Different types of small nerve fibers in eutopic endometrium and myometrium in women with endometriosis

OBJECTIVE

To investigate types of nerve fibers in endometrium and myometrium in women with endometriosis.

DESIGN

Laboratory study using human tissue.

SETTING

University-based laboratory.

PATIENT(S)

Women with and without endometriosis undergoing hysterectomy.

INTERVENTION(S)

Histologic sections of contiguous endometrial and myometrial tissues were prepared from hysterectomies performed on women with and without endometriosis.

MAIN OUTCOME MEASURE(S)

Types and density of nerve fibers in endometrium and myometrium in women with and without endometriosis were determined using a series of specific markers for neuronal structure and function: PGP9.5, NF, SP, CGRP, TH, VAChT, VIP, and NPY.

RESULT(S)

Nerve fibers stained with PGP9.5 and NF in endometrium and myometrium were significantly increased in women with endometriosis compared with women without endometriosis. Nerve fibers in the functional layer of endometrium in women with endometriosis were likely to be sensory C, a mixture of sensory A delta, sensory C, and adrenergic fibers in the basal layer of the endometrium, a mixture of sensory A delta, sensory C, adrenergic and cholinergic fibers in the myometrium.

CONCLUSION(S)

Increased nerve fiber density in endometrium and myometrium, and sensory C fibers and adrenergic nerve fibers in the endometrium in women with endometriosis may play an important role in the mechanisms of pain generation in this condition.

Growth-associated protein 43–positive sensory nerve fibers accompanied by immature vessels are located in or near peritoneal endometriotic lesions

OBJECTIVE

To investigate the topographical relationship between nerve fibers and peritoneal endometriotic lesions and to determine the origin of endometriosis-associated nerve fibers.

DESIGN

Retrospective nonrandomized study.

SETTING

University hospital endometriosis research center.

PATIENT(S)

Premenopausal women with histologically confirmed endometriosis were selected (n = 73). Peritoneal endometriotic lesions (n = 106) and unaffected peritoneal biopsies from patients without endometriosis (n = 9) were obtained.

INTERVENTION(S)

Immunohistochemistry was used to study the expression of neurofilament, substance P, smooth muscle actin, von Willebrand factor, growth-associated protein 43, nerve growth factor, and neutrophin-3 in peritoneal endometriotic lesion samples from women with symptomatic endometriosis and in peritoneal samples from women without endometriosis.

RESULT(S)

Pain-conducting substance-P-positive nerve fibers were found to be directly colocalized with human peritoneal endometriotic lesions in 74.5% of all cases. The endometriosis-associated nerve fibers are accompanied by immature blood vessels within the stroma. Nerve growth factor and neutrophin-3 are expressed by endometriotic cells. Growth-associated protein 43, a marker of neural outgrowth and regeneration, is expressed in endometriosis-associated nerve fibers but not in existing peritoneal nerves.

CONCLUSION(S)

The data provide the first evidence of direct contact between sensory nerve fibers and peritoneal endometriotic lesions. This implies that the fibers play an important role in the etiology of endometriosis-associated pelvic pain. Moreover, emerging evidence suggests that peritoneal endometriotic cells exhibit neurotrophic properties.

Endometriosis Is Associated With Prevalence of Comorbid Conditions in Migraine

OBJECTIVE

To examine the headache characteristics of women with migraine and endometriosis (EM), and differences in the prevalence of comorbid conditions between female migraineurs with EM, without EM and nonheadache controls.

BACKGROUND

Migraine and EM are common conditions in women of reproductive age, and both are influenced by ovarian hormones. The comorbidity of migraine and EM is newly recognized, but reasons for the association are uncertain.

METHODS

This is a cross-sectional study of female headache outpatients and healthy controls conducted at University of Toledo and Duke University in 2005 and 2006. After a headache specialist determined headache frequency and diagnosis (based on criteria of the second International Classification of Headache Disorders), patients completed a self-administered electronic survey with information on demographics, headache-related disability, menstrual disorders, premenstrual dysphoric disorder (PMDD), vascular event risk, and comorbid conditions, including irritable bowel syndrome (IBS), fibromyalgia (FM), chronic fatigue syndrome (CFS), interstitial cystitis (IC), depression, and anxiety.

RESULTS

Study enrolled 171 women with migraine and 104 controls. EM was reported more commonly in migraineurs than in controls (22% vs 9.6%, P < .01). Frequency of chronic headache was higher in migraineurs with EM compared to without EM (P= .002) and median headache-related disability scores were also higher in the EM group (P= .025). Symptoms of PMDD were more common in migraineurs, but frequency did not differ by EM status. Migraineurs with EM reported more menorrhagia, dysmenorrhea, and infertility compared to the migraine cohort without EM and to controls. Depression, anxiety, IBS, FM, CFS, and IC were more common in migraine with EM group than in controls. Anxiety (OR = 2.2, 95% CI 1.0-4.7), IC (OR = 10.6, 95% CI 1.9-56.5), and CFS (OR = 3.6, 95% CI 1.1-11.5) were more common in migraine with EM group, than in the cohort with migraine without EM.

CONCLUSION

Prevalence of EM is higher in women with migraine than in nonheadache controls. Migraineurs with EM have more frequent and disabling headaches, and are more likely to have other comorbid conditions affecting mood and pain, compared to migraineurs without EM.

Nerve fibres in peritoneal endometriosis

BACKGROUND

Endometriosis is a gynaecological disease that can be associated with severe pelvic pain; however, the mechanisms by which pain is generated remain unknown.

METHODS

Peritoneal endometriotic lesions and normal peritoneum were prepared from women with and without endometriosis (n = 40 and 36, respectively). Specimens were also prepared from endosalpingiosis lesions (n = 9). These sections were stained immunohistochemically with antibodies against protein gene product 9.5, neurofilament (NF), nerve growth factor (NGF), NGF receptor p75 (NGFRp75), substance P (SP), calcitonin gene-related peptide (CGRP), acetylcholine (ACh) and tyrosine hydroxylase (TH) to demonstrate myelinated, unmyelinated, sensory, cholinergic and adrenergic nerve fibres.

RESULTS

There were significantly more nerve fibres identified in peritoneal endometriotic lesions than in normal peritoneum (P < 0.001) or endosalpingiosis lesions (P < 0.001). These nerve fibres were SP, CGRP, ACh or TH immunoreactive. Many of these markers were co-localized. There was an intense NGF immunoreactivity near endometriotic glands, and NGFRp75 immunoreactive nerve fibres were present near endometriotic glands and blood vessels in the peritoneal endometriotic lesions.

CONCLUSIONS

Peritoneal endometriotic lesions were innervated by sensory Adelta, sensory C, cholinergic and adrenergic nerve fibres. These nerve fibres may play an important role in the mechanisms of pain generation in this condition.

Association between endometriosis stage, lesion type, patient characteristics and severity of pelvic pain symptoms: a multivariate analysis of over 1000 patients

BACKGROUND

The association between lesion type, disease stage and severity of pain was studied in a large group of women with endometriosis to verify whether endometrial implants at different sites determine specific complaints and to evaluate the validity of the current classification system in women with symptomatic disease.

METHODS

A total of 1054 consecutive women with endometriosis undergoing first-line conservative or definitive surgery were included. Data on age at surgery, disease stage according to the revised American Fertility Society (AFS) classification, anatomical characteristics of endometriotic lesions, and type and severity of pain symptoms were collected and analysed by multiple logistic regression.

RESULTS

Minimal endometriosis was present in 319 patients, mild in 139, moderate in 292 and severe in 304. A significant inverse relationship was demonstrated between age at surgery and moderate-to-severe dysmenorrhoea, dyspareunia and non-menstrual pain. A strong association was found between posterior cul-de-sac lesions and pain at intercourse [Wald chi (2) = 17.00, P = 0.0001; odds ratio (OR) = 2.64, 95% confidence interval (CI) = 1.68-4.24]. A correlation between endometriosis stage and severity of symptoms was observed only for dysmenorrhoea (Wald chi (2) = 5.14, P = 0.02) and non-menstrual pain (Wald chi (2) = 5.63, P = 0.018). However, the point estimates of ORs were very close to unity (respectively, 1.33, 95% CI = 1.04-1.71, and 1.01, 95% CI = 1.00-1.03).

CONCLUSIONS

The association between endometriosis stage and severity of pelvic symptoms was marginal and inconsistent and could be demonstrated only with a major increase in study power.

COX-2 overexpression in peritoneal lesions is correlated with nonmenstrual chronic pelvic pain

OBJECTIVE

To investigate cyclooxygenase (COX-2) expression within different endometriotic lesions and to assess whether these expression patterns correlate with clinical characteristics.

DESIGN

Retrospective cross-sectional study.

SETTING

University Hospital.

PATIENTS

Seventy patients with histologically confirmed exclusively peritoneal (n=20), ovarian (n=19) or deep-infiltrating (n=31) endometriosis and a detailed medical history.

INTERVENTION

Immunohistochemical analysis for COX-2 was performed on 108 endometriotic lesions.

MEASUREMENTS AND MAIN RESULTS

COX-2 intensity, percentage of stained glandular endometriotic cells, and correlation of COX-2 expression with clinicopathological parameters. Semiquantitative COX-2 expression did not differ between distinct morphological types of endometriosis and showed no association with the menstrual cycle. Patients with peritoneal-only endometriosis suffering from moderate or severe chronic pelvic pain showed significantly more frequent COX-2 overexpression than asymptomatic patients or patients with minimal symptoms. In patients with exclusively ovarian or deep-infiltrating endometriosis no association between COX-2 expression and clinical parameters, such as chronic pelvic pain, dysmenorrhoea, dyspareunia, sterility, lower urinary tract symptoms or gastrointestinal symptoms was observed.

CONCLUSION

Peritoneal endometriotic lesions with increased COX-2 expression have a special relevance for the development of chronic, nonmenstruation-associated, pelvic pain in endometriotic patients. These patients may benefit from therapy with COX-2 inhibitors.

High density of small nerve fibres in the functional layer of the endometrium in women with endometriosis

BACKGROUND

Endometriosis is a common gynaecological disease and is frequently associated with recurrent and serious pelvic pain such as dysmenorrhoea and dyspareunia, but the mechanisms by which these symptoms are generated are not well understood.

METHODS

Histological sections of endometrial tissue were prepared from endometrial curettings and hysterectomies performed on women with endometriosis (n=25 and n=10, respectively) and without endometriosis (n=47 and n=35, respectively). These were stained immunohistochemically for the highly specific polyclonal rabbit anti-protein gene product 9.5 (PGP9.5) and monoclonal mouse anti-neurofilament protein (NF) to demonstrate both myelinated and unmyelinated nerve fibres.

RESULTS

Small nerve fibres were identified throughout the basal and functional layers of the endometrium in all endometriosis patients, but were not seen in the functional layer of the endometrium in any of the women without endometriosis (P<0.001). NF-immunoreactive nerve fibres were present in the basal layer in all endometriosis patients but not in non-endometriosis patients, with one exception (P<0.001).

CONCLUSIONS

Small nerve fibres detected in the functional layer in all women with endometriosis may have important implications for understanding the generation of pain in these patients. The presence of nerve fibres in an endometrial biopsy may be a novel surrogate marker of clinical endometriosis.