The pains of endometriosis

Insights into Assessing the Genetics of Endometriosis

Endometriosis is a complex disease arising from the interplay between multiple genetic and environmental factors. The genetic variants potentially underlying the hereditary component of endometriosis have been widely investigated through hypothesis-driven candidate gene studies, an approach that generally has proven to be inherently difficult and problematic for a number of reasons. Recently, through major collaborative efforts in the endometriosis research field, hypothesis-free genome-wide approaches have started to provide new insights into potential pathways leading to development of endometriosis, as well as highlighting the phenotypic heterogeneity of the condition. This review summarizes the most recent studies investigating the genetic variation contributing to endometriosis, with a particular focus on genome-wide approaches, and discusses promising future directions of genetic research.

Pathogenesis and pathophysiology of endometriosis

Originally described over three hundred years ago, endometriosis is classically defined by the presence of endometrial glands and stroma in extrauterine locations. Endometriosis is an inflammatory, estrogen-dependent condition associated with pelvic pain and infertility. This work reviews the disease process from theories regarding origin to the molecular basis for disease sequelae. A thorough understanding of the histopathogenesis and pathophysiology of endometriosis is essential to the development of novel diagnostic and treatment approaches for this debilitating condition.

Ectopic uterine tissue as a chronic pain generator

While chronic pain is a main symptom in endometriosis, the underlying mechanisms and effective therapy remain elusive. We developed an animal model enabling the exploration of ectopic endometrium as a source of endometriosis pain. Rats were surgically implanted with autologous uterus in the gastrocnemius muscle. Within two weeks, visual inspection revealed the presence of a reddish-brown fluid-filled cystic structure at the implant site. Histology demonstrated cystic glandular structures with stromal invasion of the muscle. Immunohistochemical studies of these lesions revealed the presence of markers for nociceptor nerve fibers and neuronal sprouting. Fourteen days after surgery rats exhibited persistent mechanical hyperalgesia at the site of the ectopic endometrial lesion. Intralesional, but not contralateral, injection of progesterone was dose-dependently antihyperalgesic. Systemic administration of leuprolide also produced antihyperalgesia. In vivo electrophysiological recordings from sensory neurons innervating the lesion revealed a significant increase in their response to sustained mechanical stimulation. These results are consistent with clinical and pathological findings observed in patients with endometriosis, compatible with the ectopic endometrium as a source of pain. This model of endometriosis allows mechanistic exploration at the lesion site facilitating our understanding of endometriosis pain.

Progesterone-dependent regulation of endometrial cannabinoid receptor type 1 (CB1-R) expression is disrupted in women with endometriosis and in isolated stromal cells exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

OBJECTIVE

To examine the differentiation-related expression of cannabinoid receptor type 1 (CB1-R) messenger RNA (mRNA) and protein in endometrial tissue obtained from women with and without endometriosis and to determine the impact of acute 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure on CB1-R gene expression in isolated endometrial stromal cells.

DESIGN

Laboratory-based study.

SETTING

University-affiliated medical center.

PATIENT(S)

Women with and without endometriosis undergoing volunteer endometrial biopsies after informed consent.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Analysis of in vivo CB1-R mRNA and protein expression in human endometrial tissues and mRNA expression in isolated stromal cells after exposure to TCDD or a progesterone receptor antagonist (onapristone).

RESULT(S)

Expression of CB1-R mRNA and protein was highest during the progesterone-dominated secretory phase in control samples, but expression was minimal in the endometrial tissues acquired from women with endometriosis, regardless of the cycle phase. Although progesterone was found to induce CB1-R mRNA expression in endometrial stromal cells from control donors, steroid-induced expression of this gene was inhibited by cotreatment with either TCDD or onapristone.

CONCLUSION(S)

Our studies reveal a role for the anti-inflammatory actions of progesterone in regulating endometrial cannabinoid signaling, which is disrupted in women with endometriosis. We demonstrate for the first time that acute TCDD exposure disrupts cannabinoid signaling in the human endometrium.

Endometriosis and abdominal myofascial pain in adults and adolescents

Endometriosis and myofascial pain are common disorders with significant impact on quality of life. Increasingly, these conditions are being recognized as highly interconnected through processes that have been described for more than a century. This review is directed to this interconnection through a description of the relationships of endometriosis to proposed mechanisms of pain and chronic pain physiology; the clinical assessment of myofascial representations of this pain; and an approach to the management of these interconnected disorders.

New trends for the medical treatment of endometriosis

INTRODUCTION

Endometriosis is a benign sex hormone-dependent gynecological disease, characterized by the presence and growth of endometrial tissue outside the uterus; it affects 10% of women of reproductive age and is associated with infertility and pain. Treatment of endometriosis involves conservative or radical surgery, or medical therapies. The goals for endometriosis treatment may be the relief of pain and/or a successful pregnancy achievement in infertile patients. Treatment must be individualized with a multidisciplinary approach. The classical treatments carry adverse side effects and in some cases a negative impact on quality of life. New agents promise a distinct perspective in endometriosis treatment.

AREAS COVERED

The aim of this paper is to systematically review the literature evidence of new medical treatments for endometriosis, defined as pharmacological treatments not yet commonly available and currently under investigation.

EXPERT OPINION

These new medical therapies would be used associated with surgical treatment and, in the future, will render possible the association of hormone therapy with non-hormonal treatment for endometriosis.

Women with endometriosis are more likely to suffer from migraines: a population-based study

Previous research suggests that a co-morbid relationship exists between migraine and endometriosis; however, results have been inconsistent. In addition, female hormones, which are important in the pathogenesis and management of endometriosis, have been reported to precipitate migraine attacks and may confound the results. The aim of this population-based cohort study was to explore the relationship between migraine and endometriosis in women of reproductive age (18-51 years). Data were derived from the National Health Insurance Research Database of Taiwan, which contains outpatient and inpatient records from 2000 to 2007. Our study cohort included 20,220 endometriosis patients and 263,767 controls without endometriosis. We analyzed the prevalence of migraine in these women as recorded during the eight years of the database. Our results found that patients with endometriosis were more likely to suffer migraine headaches compared to controls (odds ratio [OR], 1.70; 95% confidence interval [CI] [1.59, 1.82]; p<0.001). In addition, the co-morbid association between migraine and endometriosis remained significant after the data were controlled for age and frequently utilized hormone therapies (OR, 1.37; 95% CI, [1.27, 1.47]; p<0.001). The results of this cohort study support the existence of a co-morbid relationship between migraine and endometriosis, even after adjusting for the possible effects of female hormone therapies on migraine attacks.

Enzymes of the AKR1B and AKR1C Subfamilies and Uterine Diseases

Endometrial and cervical cancers, uterine myoma, and endometriosis are very common uterine diseases. Worldwide, more than 800,000 women are affected annually by gynecological cancers, as a result of which, more than 360,000 die. During their reproductive age, about 70% of women develop uterine myomas and 10-15% suffer from endometriosis. Uterine diseases are associated with aberrant inflammatory responses and concomitant increased production of prostaglandins (PG). They are also related to decreased differentiation, due to low levels of protective progesterone and retinoic acid, and to enhanced proliferation, due to high local concentrations of estrogens. The pathogenesis of these diseases can thus be attributed to disturbed PG, estrogen, and retinoid metabolism and actions. Five human members of the aldo-keto reductase 1B (AKR1B) and 1C (AKR1C) superfamilies, i.e., AKR1B1, AKR1B10, AKR1C1, AKR1C2, and AKR1C3, have roles in these processes and can thus be implicated in uterine diseases. AKR1B1 and AKR1C3 catalyze the formation of PGF2α, which stimulates cell proliferation. AKR1C3 converts PGD2 to 9α,11β-PGF2, and thus counteracts the formation of 15-deoxy-PGJ2, which can activate pro-apoptotic peroxisome-proliferator-activated receptor γ. AKR1B10 catalyzes the reduction of retinal to retinol, and thus lessens the formation of retinoic acid, with potential pro-differentiating actions. The AKR1C1-AKR1C3 enzymes also act as 17-keto- and 20-ketosteroid reductases to varying extents, and are implicated in increased estradiol and decreased progesterone levels. This review comprises an introduction to uterine diseases and AKR1B and AKR1C enzymes, followed by an overview of the current literature on the AKR1B and AKR1C expression in the uterus and in uterine diseases. The potential implications of the AKR1B and AKR1C enzymes in the pathophysiologies are then discussed, followed by conclusions and future perspectives.

Sprouted innervation into uterine transplants contributes to the development of hyperalgesia in a rat model of endometriosis

Endometriosis is an enigmatic painful disorder whose pain symptoms remain difficult to alleviate in large part because the disorder is defined by extrauteral endometrial growths whose contribution to pain is poorly understood. A rat model (ENDO) involves autotransplanting on abdominal arteries uterine segments that grow into vascularized cysts that become innervated with sensory and sympathetic fibers. ENDO rats exhibit vaginal hyperalgesia. We used behavioral, physiological, and immunohistochemical methods to test the hypothesis that cyst innervation contributes to the development of this hyperalgesia after transplant. Rudimentary sensory and sympathetic innervation appeared in the cysts at two weeks, sprouted further and more densely into the cyst wall by four weeks, and matured by six weeks post-transplant. Sensory fibers became abnormally functionally active between two and three weeks post-transplant, remaining active thereafter. Vaginal hyperalgesia became significant between four and five weeks post-transplant, and stabilized after six to eight weeks. Removing cysts before they acquired functional innervation prevented vaginal hyperalgesia from developing, whereas sham cyst removal did not. Thus, abnormally-active innervation of ectopic growths occurs before hyperalgesia develops, supporting the hypothesis. These findings suggest that painful endometriosis can be classified as a mixed inflammatory/neuropathic pain condition, which opens new avenues for pain relief. The findings also have implications beyond endometriosis by suggesting that functionality of any transplanted tissue can be influenced by the innervation it acquires.

Ovarian endometrioma: severe pelvic pain is associated with deeply infiltrating endometriosis

BACKGROUND

The objective of this study was to evaluate the significance of severe preoperative pain for patients presenting with ovarian endometrioma (OMA).

METHODS

Three hundred consecutive patients with histologically proven OMA were enrolled at a single university tertiary referral centre between January 2004 and May 2010. Complete surgical excision of all recognizable endometriotic lesions was performed for each patient. Pain intensity was assessed with a 10-cm visual analogue scale (VAS). Pain was considered as severe when VAS was ≥ 7. Prospective preoperative assessment of type and severity of pain symptoms (VAS) was compared with the peroperative findings (surgical removal and histological analysis) of endometriomas and associated deeply infiltrating endometriosis. Correlations were sought with univariate analysis and a multiple regression logistic model.

RESULTS

After multiple logistic regression analysis, uterosacral ligaments involvement was related with a high severity of chronic pelvic pain [odds ratios (OR) = 2.1; 95% confidence interval (CI): 1.1-4.3] and deep dyspareunia (OR = 2.0; 95% CI: 1.1-3.5); vaginal involvement was related with a higher intensity of lower urinary symptoms (OR = 13.4; 95% CI: 3.2-55.8); intestinal involvement was related with an increased severity of dysmenorrhoea (OR = 5.2; 95% CI: 2.7-10.3) and gastro-intestinal symptoms (OR = 7.1; 95% CI: 3.3-15.3).

CONCLUSIONS

In case of OMA, severe pelvic pain is significantly associated with deeply infiltrating lesions. In this situation, the practitioner should perform an appropriate preoperative imaging work-up in order to evaluate the existence of associated deep nodules and inform the patient in order to plan the surgical intervention strategy.

Baropodometry on women suffering from chronic pelvic pain--a cross-sectional study

Background

Previous studies have associated chronic pelvic pain with a stereotyped pattern of movement and posture, lack of normal body sensations, a characteristic pain distribution. We aimed at evaluating if these postural changes are detectable in baropodometry results in patients with chronic pelvic pain.

Methods

We performed a prospective study in a university hospital. We selected 32 patients suffering from chronic pelvic pain (study group) and 30 women without this pathology (regular gynecological work out - control group). Pain scores and baropodometric analysis were performed.

Results

As expected, study group presented higher pain scores than control group. Study and control groups presented similar averages for the maximum pressures to the left and right soles as well as soles supports in the forefeet and hind feet. Women suffering from chronic pelvic pain did not present differences in baropodometric analysis when compared to healthy controls.

Conclusions

This data demonstrates that postural abnormalities resulting from CPP could not be demonstrated by baropodometric evaluation. Other postural measures should be addressed to evaluate pelvic pain patients.

Effect of esophagus distention on urinary bladder function in rats

AIMS

Micturition process is a spinobulbospinal reflex that is affected by the viscero-visceral interactions due to convergent inputs into spinal and/or supraspinal centers controlling that reflex. Although interaction between bladder and other pelvic organs, such as colon, are well studied, the viscero-visceral interaction between urinary bladder and internal organs in other regions are rarely studied.

METHODS

In the present study, continuous filling cystometry recordings, in male rats, were used to investigate the effects of mechanical stimulation of distal-esophagus (distention), as well as, electrical stimulation of abdominal branches of the vagus nerve on urinary bladder micturition cycles.

RESULTS

Distal esophagus distention and electrical stimulation of the vagus nerve significantly increased the micturition frequency through decreasing the time of the storage phase of the micturition cycle. However, bilateral cervical vagotomy eliminated the effects of distal esophagus distention and electrical stimulation of vagus nerve on micturition cycles.

CONCLUSIONS

The results of this study indicate that there is a viscero-visceral interaction between esophagus and urinary bladder, which is mediated through vagal afferents. Understanding the properties of the viscero-visceral interactions affecting the urinary bladder will help in the diagnosis and management of micturition problems.

[Intestinal endometriosis]

Endometriosis affects 6 to 10 % of all women of childbearing age. Intestinal involvement is defined by muscularis infiltration and has been estimated to occur in 8 % to 12 % of women with endometriosis. The most common sites are rectum, sigmoid and ileocaecal junction. In most cases, intestinal endometriosis is associated with deep infiltrating endometriosis, multifocal and aggressive form of endometriosis, responsible for refractory pelvic pain and infertility. The symptoms are nonspecific but are characterized by cyclic exacerbation of pain. The preoperative work-up includes a rectal endoscopic ultrasonography, a transvaginal ultrasonography, a pelvic magnetic resonance imaging and a multidetector CT scan. There is currently no cure other than surgical removal of lesions. Medical treatments are based on a hormone used to block ovarian function.

Endometriosis and headache

Headache and endometriosis show some similarities in their clinical and epidemiological features that are probably due to the influence of female sexual hormones on both disorders. Epidemiological studies indicate that they are comorbid disorders. However, the nature of the comorbidity is not known with certainty, but a likely explanation may be common susceptibility genes. Another possibility is that, because they both are related to pain, increased pain sensitivity induced by one of the disorders may lead to a higher likelihood of developing the other, possibly mediated by nitrogen oxide or prostaglandins. A common link to the widespread use of estroprogestins may seem less probable. For physicians dealing with women with either of these disorders, awareness of the comorbidity may be helpful in the treatment of the patient.

TRPV1 and TRPA1 function and modulation are target tissue dependent

The nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF) families of growth factors regulate the sensitivity of sensory neurons. The ion channels transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential channel, subfamily A, member 1 (TRPA1), are necessary for development of inflammatory hypersensitivity and are functionally potentiated by growth factors. We have shown previously that inflamed skin exhibits rapid increases in artemin mRNA with slower, smaller increases in NGF mRNA. Here, using mice, we show that, in inflamed colon, mRNA for both growth factors increased with a pattern distinct from that seen in skin. Differences were also seen in the pattern of TRPV1 and TRPA1 mRNA expression in DRG innervating inflamed skin and colon. Growth factors potentiated capsaicin (a specific TRPV1 agonist) and mustard oil (a specific TRPA1 agonist) behavioral responses in vivo, raising the question as to how these growth factors affect individual afferents. Because individual tissues are innervated by afferents with unique properties, we investigated modulation of TRPV1 and TRPA1 in identified afferents projecting to muscle, skin, and colon. Muscle and colon afferents are twice as likely as skin afferents to express functional TRPV1 and TRPA1. TRPV1 and TRPA1 responses were potentiated by growth factors in all afferent types, but compared with skin afferents, muscle afferents were twice as likely to exhibit NGF-induced potentiation and one-half as likely to exhibit artemin-induced potentiation of TRPV1. Furthermore, skin afferents showed no GDNF-induced potentiation of TRPA1, but 43% of muscle and 38% of colon afferents exhibited GDNF-induced potentiation. These results show that interpretation of afferent homeostatic mechanisms must incorporate properties that are specific to the target tissue.

Proangiogenic Tie2(+) macrophages infiltrate human and murine endometriotic lesions and dictate their growth in a mouse model of the disease

Endometriosis affects women of reproductive age, causing infertility and pain. Although immune cells are recruited in endometriotic lesions, their role is unclear. Tie2-expressing macrophages (TEMs) have nonredundant functions in promoting angiogenesis and growth of experimental tumors. Here we show that human TEMs infiltrate areas surrounding newly formed endometriotic blood vessels. We set up an ad hoc mouse model in which TEMs, and not Tie2-expressing endothelial cells, are targeted. We transplanted in wild-type recipients bone marrow cells expressing a suicide gene (Herpes simplex virus type 1 thymidine kinase) under the Tie2 promoter/enhancer. TEMs infiltrated endometriotic lesions. TEM depletion by ganciclovir administration arrested the growth of established lesions, without toxicity. Lesion architecture was disrupted, with: i) loss of glandular organization, ii) reduced neovascularization, and iii) activation of caspase 3 in CD31(+) endothelial cells. Thus, TEMs are important for maintaining the viability of newly formed vessels and represent a potential therapeutic target in endometriosis.

Pelvic pain in women: clinical and scientific aspects

PURPOSE OF REVIEW

Pelvic pain is a common complaint of women that is frequently poorly managed. This review considers the current understanding of the mechanisms of pain perception and the development of chronic pain in the context of three gynaecological pain conditions. Recent advances in the management of these conditions are then discussed.

RECENT FINDINGS

Persistent pelvic pain is associated with central changes, reflected by alterations in psychology, brain structure and function, and dysfunction of the hypothalamic-pituitary-adrenal axis. The many similarities among the conditions support the notion that chronic pain should be treated as a symptom in its own right, however, obtaining a diagnosis remains important to patients. Few new treatments have been developed recently, however, older treatments are being subjected to more rigorous testing and improvements in phenotyping should lead to better design of clinical trials.

SUMMARY

Good quality, well designed clinical trials are urgently required to improve the treatment of pelvic pain in women. However, a variety of successful treatments exist and outcomes can be optimized by individualizing treatment strategies in the context of a multidisciplinary package.

Impact of endometriosis on quality of life and work productivity: a multicenter study across ten countries

OBJECTIVE

To assess the impact of endometriosis on health-related quality of life (HRQoL) and work productivity.

DESIGN

Multicenter cross-sectional study with prospective recruitment.

SETTING

Sixteen clinical centers in ten countries.

PATIENT(S)

A total of 1,418 premenopausal women, aged 18-45 years, without a previous surgical diagnosis of endometriosis, having laparoscopy to investigate symptoms or to be sterilized.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Diagnostic delay, HRQoL, and work productivity.

RESULT(S)

There was a delay of 6.7 years, principally in primary care, between onset of symptoms and a surgical diagnosis of endometriosis, which was longer in centers where women received predominantly state-funded health care (8.3 vs. 5.5 years). Delay was positively associated with the number of pelvic symptoms (chronic pelvic pain, dysmenorrhoea, dyspareunia, and heavy periods) and a higher body mass index. Physical HRQoL was significantly reduced in affected women compared with those with similar symptoms and no endometriosis. Each affected woman lost on average 10.8 hours (SD 12.2) of work weekly, mainly owing to reduced effectiveness while working. Loss of work productivity translated into significant costs per woman/week, from US$4 in Nigeria to US$456 in Italy.

CONCLUSION(S)

Endometriosis impairs HRQoL and work productivity across countries and ethnicities, yet women continue to experience diagnostic delays in primary care. A higher index of suspicion is needed to expedite specialist assessment of symptomatic women. Future research should seek to clarify pain mechanisms in relation to endometriosis severity.

The display of paced mating behavior in a rat model of endometriosis

Endometriosis is a disorder associated with chronic pelvic pain and ill effects on women's sexual health. The present study examined the effects of pelvic endometriotic implants on the display of paced mating behavior in female rats. Approximately 2 months after the surgical induction of endometriosis, rats were tested for paced mating behavior during proestrus (Experiment 1) or after bilateral ovariectomy and hormone replacement (Experiment 2). Although endometriotic implants were confirmed at autopsy, rats with surgical endometriosis in both experiments exhibited normal patterns of paced mating behavior. The positive relationship between implant material and contact-return latency following ejaculation in Experiment 2 suggests that the sensitivity to vigorous mating stimulation may be influenced by 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.

Novel estrogen-related genes and potential biomarkers of ovarian endometriosis identified by differential expression analysis

In the search for novel biomarkers of endometriosis, we selected 152 genes from the GeneLogic database based on results of genome-wide expression analysis of ovarian endometriosis, plus 20 genes related to estrogen metabolism and action. We then performed low-density array analysis of these 172 genes on 11 ovarian endometriosis samples and 9 control endometrium samples. Principal component analysis of the gene expression levels showed clear separation between the endometriosis and control groups. We identified 78 genes as differentially expressed. Based on Ingenuity pathway analysis, these differentially expressed genes were arranged into groups according to biological function. These analyses revealed that 32 differentially expressed genes are estrogen related, 23 of which have not been reported previously in connection with endometriosis. Functional annotation showed that 25 and 22 genes are associated with the biological terms "secreted" and "extracellular region", respectively. Differential expression of 4 out of 5 genes related to estrogen metabolism and action (ESR1, ESR2, PGR and BGN) was also confirmed by immunohistochemistry. Our study thus reveals differential expression of several genes that have not previously been associated with endometriosis and that encode potential novel biomarkers and drug targets.

Quality of life associated to chronic pelvic pain is independent of endometriosis diagnosis--a cross-sectional survey

BACKGROUND

Pain is strongly related to poor quality of life. We performed a cross-sectional study in a university hospital to investigate quality of life in women suffering from chronic pelvic pain (CPP) due to endometriosis and others conditions.

METHODS

Fifty-seven patients aged between 25 and 48 years-old submitted to laparoscopy because of CPP were evaluated for quality of life and depressive symptoms. Quality of life was accessed by a quality of life instrument [World Health Organization Quality of Life Assessment-Bref (WHOQOL-bref)]. Causes of pelvic pain were determined and severity of CPP was measured with a visual analogue scale. According to the intensity of pelvic pain score, patients were classified in two groups (group Low CPP < 25th percentile visual analogue scale and group High CPP > 25th percentile). Four dimensions on quality of life were measured (physical, psychological, social and environmental). We stratified the analysis of quality of life according CPP causes (presence or not of endometriosis in laparoscopy).

RESULTS

Patients with higher pain scores presented lower quality of life status in psychological and environmental dimensions. We found a negative correlation between pain scores and psychological dimension of quality of life (r = -0.310, P = .02). Quality of life scores were similar between groups with and without endometriosis (physical 54.2 ± 12.8 and 51.1 ± 13.8, P = 0.504; psychological 56.2 ± 14.4 and 62.8 ± 12.4, P = 0.182; social 55.6 ± 18.2 and 62.1 ± 19.1, P = 0.325; environmental 59.2 ± 11.7 61.2 ± 10.8, P = 0.608; respectively)

CONCLUSIONS

Higher pain scores are correlated to lower quality of life; however the fact of having endometriosis in addition to CPP does not have an additional impact upon the quality of life.

Endometriosis for the colorectal surgeon

Endometriosis is defined as the presence of endometrial glands and stroma outside the uterine cavity. Although the exact pathophysiology is unclear, endometriosis is a well-known cause of pelvic pain and infertility in reproductive-aged women. Endometriosis can have extrapelvic manifestations relevant for colorectal surgeons to appreciate, such as cyclic constipation, diarrhea, hematochezia, and dyschezia. The treatment of endometriosis involves a combination of medical and surgical interventions where close collaboration between the gynecologist and colorectal surgeon can help achieve prolonged periods of symptom remission.

Inhibition of transcription, expression, and secretion of the vascular epithelial growth factor in human epithelial endometriotic cells by romidepsin

OBJECTIVE

To investigate whether the histone deacetylase (HDAC) inhibitor romidepsin down-regulates VEGF (vascular endothelial growth factor) gene expression and abrogates VEGF protein secretion in human epithelial endometriotic cells.

DESIGN

In vitro study with human immortalized epithelial endometriotic cells.

SETTING

University hospital.

PATIENT(S)

Not applicable.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Real-time reverse-transcriptase polymerase chain reaction to evaluate VEGF gene expression, immunoblot analysis to evaluate protein expression, and enzyme-linked immunosorbent assay to evaluate VEGF protein secretion into the culture medium.

RESULT(S)

Treatment of 11z human endometriotic cells with romidepsin statistically significantly inhibited VEGF gene transcription and down-regulated VEGF protein expression. Moreover, romidepsin abrogated the secretion of VEGF protein into the culture medium. Romidepsin also reduced the expression of hypoxia-inducible factor-1α (HIF-1α), which is implicated in the transcription of the VEGF gene, in cobalt chloride-pretreated (to mimic hypoxic conditions) 11z cultures.

CONCLUSION(S)

Romidepsin targets VEGF at the transcriptional level, which subsequently leads to the reduction of secreted VEGF (the "active" form of VEGF). Therefore, romidepsin may be a potential therapeutic candidate against angiogenesis in endometriosis.

Urinary peptide profiling identifies a panel of putative biomarkers for diagnosing and staging endometriosis

OBJECTIVE

To identify a potential diagnostic endometriosis marker using matrix-enhanced laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS)-based urinary proteomics.

DESIGN

Prospective randomized pilot study.

SETTING

University hospital, tertiary referral center for endometriosis.

PATIENT(S)

53 women undergoing laparoscopic surgery for pain and/or infertility comprising 30 women without endometriosis and 23 with endometriosis.

INTERVENTION(S)

Laparoscopy and urine specimens.

MAIN OUTCOME MEASURE(S)

Urinary peptide profiles.

RESULT(S)

We observed distinct patterns of peptide profiles in the urine samples of women presenting with typical clinical symptoms of endometriosis. Six statistically significant putative peptide markers were identified (four during the periovulatory phase and two during the luteal phase) by comparing controls with moderate/severe endometriosis patients. The periovulatory peptide mass of 1,767.1 Da and the luteal peptide mass of 1,824.3 Da both showed a sensitivity of 75% and a specificity of 85% and 71%, respectively. Also detected were seven peptide markers (two during the periovulatory phase and five during the luteal phase) by comparing the urinary peptide profiles of patients with minimal/mild to moderate/severe endometriosis. The periovulatory peptide mass of 3,280.9 Da and the luteal peptide mass of 1,933.8 Da showed a sensitivity of 82% and 75% and a specificity of 88% and 75%, respectively.

CONCLUSION(S)

Urinary proteomic analysis may provide a novel method of diagnosing and staging endometriosis.

Aldo-keto reductases AKR1C1, AKR1C2 and AKR1C3 may enhance progesterone metabolism in ovarian endometriosis

Endometriosis is a very common disease that is characterized by increased formation of estradiol and disturbed progesterone action. This latter is usually explained by a lack of progesterone receptor B (PR-B) expression, while the role of pre-receptor metabolism of progesterone is not yet fully understood. In normal endometrium, progesterone is metabolized by reductive 20α-hydroxysteroid dehydrogenases (20α-HSDs), 3α/β-HSDs and 5α/β-reductases. The aldo-keto reductases 1C1 and 1C3 (AKR1C1 and AKR1C3) are the major reductive 20α-HSDs, while the oxidative reaction is catalyzed by 17β-HSD type 2 (HSD17B2). Also, 3α-HSD and 3β-HSD activities have been associated with the AKR1C isozymes. Additionally, 5α-reductase types 1 and 2 (SRD5A1, SRD5A2) and 5β-reductase (AKR1D1) are responsible for the formation of 5α- and 5β-reduced pregnanes. In this study, we examined the expression of PR-AB and the progesterone metabolizing enzymes in 31 specimens of ovarian endometriosis and 28 specimens of normal endometrium. Real-time PCR analysis revealed significantly decreased mRNA levels of PR-AB, HSD17B2 and SRD5A2, significantly increased mRNA levels of AKR1C1, AKR1C2, AKR1C3 and SRD5A1, and negligible mRNA levels of AKR1D1. Immunohistochemistry staining of endometriotic tissue compared to control endometrium showed significantly lower PR-B levels in epithelial cells and no significant differences in stromal cells, there were no significant differences in the expression of AKR1C3 and significantly higher AKR1C2 levels were seen only in stromal cells. Our expression analysis data at the mRNA level and partially at the cellular level thus suggest enhanced metabolism of progesterone by SRD5A1 and the 20α-HSD and 3α/β-HSD activities of AKR1C1, AKR1C2 and AKR1C3.

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.

Antiproliferative effects of cannabinoid agonists on deep infiltrating endometriosis

Deep infiltrating endometriosis (DIE) is characterized by chronic pain, hyperproliferation of endometriotic cells and fibrosis. Since cannabinoids are endowed with antiproliferative and antifibrotic properties, in addition to their psychogenic and analgesic effects, cannabinoid agonists have been evaluated in DIE both in vitro and in vivo. The in vitro effects of the cannabinoid agonist WIN 55212-2 were evaluated on primary endometriotic and endometrial stromal and epithelial cell lines extracted from patients with or without DIE. Cell proliferation was determined by thymidine incorporation and production of reactive oxygen species by spectrofluorometry. ERK and Akt pathways were studied by immunoblotting. Immunoblotting of α-smooth muscle actin was studied as evidence of myofibroblastic transformation. The in vivo effects of WIN 55212-2 were evaluated on Nude mice implanted with human deep infiltrating endometriotic nodules. The in vitro treatment of stromal endometriotic cells by WIN 55212-2 decreased cell proliferation, reactive oxygen species production, and α-smooth muscle actin expression. The decrease in cell proliferation induced by WIN 55212-2 was not associated with a decrease in ERK activation, but was associated with the inhibition of Akt activation. WIN 55212-2 abrogated the growth of endometriotic tissue implanted in Nude mice. Cannabinoid agonists exert anti-proliferative effects on stromal endometriotic cells linked to the inhibition of the Akt pathway. These beneficial effects of cannabinoid agonists on DIE have been confirmed in vivo.

Dietary therapy: a new strategy for management of chronic pelvic pain

Chronic pelvic pain (CPP) can be identified as a chronic nociceptive, inflammatory and neuropathic pain characterised by spontaneous pain and an exaggerated response to painful and/or innocuous stimuli. This pain condition is extremely debilitating and usually difficult to treat. Currently, the main approaches to treatment include counselling supported by reassuring ultrasound scanning or psychotherapy, attempting to provide reassurance using laparoscopy to exclude serious pelvic pathology, hormonal therapy and neuroablative treatment to interrupt nerve pathways. Dietary supplementation has been suggested as a means to treat chronic medical illnesses that are poorly responsive to prescription drugs or in which therapeutic options are limited, costly or carry a high side-effect profile. A comprehensive search of the PubMed database was performed using the search terms 'chronic pelvic pain', 'oxidative stress', 'antioxidants' and 'dietary therapy'. The systematic review focuses on both randomised and non-randomised controlled trials from 2005 onwards, in which CPP was the end point. Given the complexity and not well-understood aetiology of CPP, its treatment is often unsatisfactory and limited to partial symptom relief. Dietary therapy with antioxidants improves function of the immune system and in fighting free radical damage. Agents with antioxidant activity are able to improve CPP without undesired effects and any important metabolic changes associated with hormonal suppression therapy. In conclusion, dietary therapy with antioxidants could be considered as a new effective strategy in the long term for CPP, and may be better accepted by patients. Further randomised trials with larger series and long-term follow-up to confirm these observations are needed.

Evaluation of polymorphisms in predicted target sites for micro RNAs differentially expressed in endometriosis

Previous microarray analyses identified 22 microRNAs (miRNAs) differentially expressed in paired ectopic and eutopic endometrium of women with and without endometriosis. To investigate further the role of these miRNAs in women with endometriosis, we conducted an association study aiming to explore the relationship between endometriosis risk and single-nucleotide polymorphisms (SNPs) in miRNA target sites for these differentially expressed miRNAs. A panel of 102 SNPs in the predicted miRNA binding sites were evaluated for an endometriosis association study and an ingenuity pathway analysis was performed. Fourteen rare variants were identified in this study. We found SNP rs14647 in the Wolf-Hirschhorn syndrome candidate gene1 (WHSC1) 3'UTR (untranslated region) was associated with endometriosis-related infertility presenting an odds ratio of 12.2 (95% confidence interval = 2.4-60.7, P = 9.03 × 10(-5)). SNP haplotype AGG in the solute carrier family 22, member 23 (SLC22A23) 3'UTR was associated with endometriosis-related infertility and more severe disease. With the individual genotyping data, ingenuity pathways analysis identified the tumour necrosis factor and cyclin-dependant kinase inhibitor as major factors in the molecular pathways. Significant associations between WHSC1 alleles and endometriosis-related infertility and SLC22A23 haplotypes and the disease severe stage were identified. These findings may help focus future research on subphenotypes of this disease. Replication studies in independent large sample sets to confirm and characterize the involvement of the gene variation in the pathogenesis of endometriosis are needed.

Meta-analysis of genome-wide association scans for genetic susceptibility to endometriosis in Japanese population

To identify susceptibility genes for endometriosis in Japanese women, genome-wide association (GWA) analysis was performed using two case-control cohorts genotyped with the Affymetrix Mapping 500K Array or Genome-Wide Human SNP Array 6.0. In each of the two array cohorts, stringent quality control (QC) filters were applied to newly obtained genotype data, together with previously analyzed data from the Japanese Integrated Database Project. After QC-based filtering of samples and single nucleotide polymorphisms (SNPs) in each cohort, 282 838 SNPs in both genotyping platforms were tested for association with endometriosis using a meta-analysis of the two GWA studies with 696 patients with endometriosis and 825 controls. The meta-analysis revealed that a common susceptibility locus conferring a large effect on the disease risk was unlikely. On the other hand, an excess of SNPs with P-values <10(-4) (36 vs 28 SNPs expected by chance) was observed in the meta-analysis. Of note, four of the top five SNPs with P-values <10(-5) were located in and around IL1A (interleukin 1α), which might be a functional candidate gene for endometriosis. Further studies with larger case-control cohorts will be necessary to elucidate the genetic risk factors.

Endocannabinoid involvement in endometriosis

Endometriosis is a disease common in women that is defined by abnormal extrauteral growths of uterine endometrial tissue and associated with severe pain. Partly because how the abnormal growths become associated with pain is poorly understood, the pain is difficult to alleviate without resorting to hormones or surgery, which often produce intolerable side effects or fail to help. Recent studies in a rat model and women showed that sensory and sympathetic nerve fibers sprout branches to innervate the abnormal growths. This situation, together with knowledge that the endocannabinoid system is involved in uterine function and dysfunction and that exogenous cannabinoids were once used to alleviate endometriosis-associated pain, suggests that the endocannabinoid system is involved in both endometriosis and its associated pain. Herein, using a rat model, we found that CB1 cannabinoid receptors are expressed on both the somata and fibers of both the sensory and sympathetic neurons that innervate endometriosis's abnormal growths. We further found that CB1 receptor agonists decrease, whereas CB1 receptor antagonists increase, endometriosis-associated hyperalgesia. Together these findings suggest that the endocannabinoid system contributes to mechanisms underlying both the peripheral innervation of the abnormal growths and the pain associated with endometriosis, thereby providing a novel approach for the development of badly-needed new treatments.

Clinical practice. Endometriosis

A healthy 25-year-old woman presents with worsening dysmenorrhea, pain of recent onset in the left lower quadrant, and dyspareunia. She has regular menstrual cycles, and her last menstrual period was 3 weeks before presentation. How should this patient be evaluated and treated?