Association of leptin with inflammatory cytokines and lymphocyte subpopulations in peritoneal fluid of patients with endometriosis

A narrative review about the intricate crosstalk among endometrium, adipose tissue, and neurons in endometriosis. The multifaceted role of leptin

Endometriosis is a highly prevalent gynecological disease characterized by the presence of endometrium-like tissue outside the uterus, whose etiopathology is far from being elucidated. The most frequent complains of patients are pelvic pain and infertility. Increasing evidence supports the systemic impact of endometriosis suggesting that an intricate crosstalk among distinct organs underlies the development of the disease. In this setting, endometriosis patients present an increased risk for developing other diseases, such as cancer, cardiovascular pathologies, and autoimmune diseases, and manifest neurologic disturbances, including neuropathic hyperalgesia. Whilst the ovary-secreted estrogen dependency of ectopic endometrium growth is well established, we conjecture that adipose tissue-secreted molecules also intervene in endometriosis development and pain manifestation. In fact, women with endometriosis present a peculiar pattern of adipokine secretion that ensues the disease onset. Unexpectedly, the levels of adipose tissue-secreted molecules in those women present similarities with those found in patients with obesity, despite the recognized association of low body mass index with endometriosis. Taking this evidence into consideration, we hypothesize that endometriosis patients present a dysfunctional adipose tissue, which is associated with enhanced metabolism and unregulated browning that not only intervene in the control of body weight but also in peculiar pain processing pathways.

Niclosamide targets the dynamic progression of macrophages for the resolution of endometriosis in a mouse model

Due to the vital roles of macrophages in the pathogenesis of endometriosis, targeting macrophages could be a promising therapeutic direction. Here, we investigated the efficacy of niclosamide for the resolution of a perturbed microenvironment caused by dysregulated macrophages in a mouse model of endometriosis. Single-cell transcriptomic analysis revealed the heterogeneity of macrophages including three intermediate subtypes with sharing characteristics of traditional “small” or “large” peritoneal macrophages (SPMs and LPMs) in the peritoneal cavity. Endometriosis-like lesions (ELL) enhanced the differentiation of recruited macrophages, promoted the replenishment of resident LPMs, and increased the ablation of embryo-derived LPMs, which were stepwise suppressed by niclosamide. In addition, niclosamide restored intercellular communications between macrophages and B cells. Therefore, niclosamide rescued the perturbed microenvironment in endometriosis through its fine regulations on the dynamic progression of macrophages. Validation of similar macrophage pathogenesis in patients will further promote the clinical usage of niclosamide for endometriosis treatment.

Clues for Improving the Pathophysiology Knowledge for Endometriosis Using Plasma Micro-RNA Expression

The pathophysiology of endometriosis remains poorly understood. The aim of the present study was to investigate functions and pathways associated with the various miRNAs differentially expressed in patients with endometriosis. Plasma samples of the 200 patients from the prospective "ENDO-miRNA" study were analyzed and all known human miRNAs were sequenced. For each miRNA, sensitivity, specificity, and ROC AUC values were calculated for the diagnosis of endometriosis. miRNAs with an AUC ≥ 0.6 were selected for further analysis. A comprehensive review of recent articles from the PubMed, Clinical Trials.gov, Cochrane Library, and Web of Science databases was performed to identify functions and pathways associated with the selected miRNAs. In total, 2633 miRNAs were found in the patients with endometriosis. Among the 57 miRNAs with an AUC ≥ 0.6: 20 had never been reported before; one (miR-124-3p) had previously been observed in endometriosis; and the remaining 36 had been reported in benign and malignant disorders. miR-124-3p is involved in ectopic endometrial cell proliferation and invasion and plays a role in the following pathways: mTOR, STAT3, PI3K/Akt, NF-κB, ERK, PLGF-ROS, FGF2-FGFR, MAPK, GSK3B/β-catenin. Most of the remaining 36 miRNAs are involved in carcinogenesis through cell proliferation, apoptosis, and invasion. The three main pathways involved are Wnt/β-catenin, PI3K/Akt, and NF-KB. Our results provide evidence of the relation between the miRNA profiles of patients with endometriosis and various signaling pathways implicated in its pathophysiology.

Serum and peritoneal fluid leptin levels in endometriosis: a systematic review and meta-analysis

The role of leptin in the development of endometriosis has been investigated previously. However, researches on the change of leptin levels in endometriosis remains controversial. So, we aimed to clarify changes of leptin levels in patients with endometriosis and their association with the progression of endometriosis. We searched PubMed, Embase, Web of Science, and The Cochrane Library to identify relevant studies published before May 25, 2020. The detected levels of leptin in patients with endometriosis versus controls were evaluated in this meta-analysis. Eighteen studies met our inclusion criteria, five studies detected serum, nine detected peritoneal fluid and another four detected both serum and peritoneal fluid leptin levels. The overall results showed that peritoneal fluid leptin levels in patients with endometriosis was significantly higher than that in the control group, but the serum and corrected peritoneal fluid leptin levels were comparable in both groups. Subgroup analysis failed to eliminate the high degree of heterogeneity included in the studies and showed that peritoneal fluid leptin levels were significantly elevated in both early and advanced endometriosis. In conclusion, peritoneal fluid rather than serum leptin levels was elevated in patients with endometriosis, which did not seem to be related to the severity of endometriosis, but was related to body mass index.

Association of leptin and adiponectin levels with endometriosis: a systematic review and meta-analysis

BACKGROUND

We aimed to summarize the available data regarding the levels of leptin and adiponectin and the key modulators of endometriosis compared to the controls.

METHODS

The electronic databases such as MEDLINE, Embase, Scopus, Cochrane Library, and Web of Science were searched up to October 2020. The circulating and peritoneal levels of leptin and circulating levels of adiponectin were included. We used the Cochrane's Q test and the I² statistic in this study. These tests' weighted mean difference (WMD) and 95% CIs were considered as the summary effect size. They were then pooled using a random-effects model with the DerSimonian-Laird method.

RESULTS

Twenty eligible articles (or 25 studies) with 2645 participants (1362 women with endometriosis and 1283 controls) were included. Pooled results showed that women with endometriosis had significantly higher leptin levels (WMD = 4.45 mg/ml, 95%CI = 2.42-6.49, p < .01) and leptin/BMI ratio (WMD = 0.32 mg/ml, 95%CI = 0.23-0.42, p < .001) than the controls, whereas adiponectin levels (WMD = -0.24 mg/ml, 95%CI = -4.27 to -0.01, p = .038) were significantly lower. The pooled results also indicated significantly lower leptin levels in women with advanced-stage endometriosis (WMD = -8.07 mg/ml, 95%CI = -14.22 to -1.92, p = .01) than in the early stage. It was found, however, that there were no significant differences in adiponectin levels of women with advanced-stage endometriosis (WMD = -0.16 mg/ml, 95%CI = -0.64 to 0.32, p = .512) and the early-stage ones.

CONCLUSION

We showed that leptin levels and leptin/BMI ratio were significantly higher in women with endometriosis than the controls. Nonetheless, patients with endometriosis had significantly lower levels of adiponectin than the controls.

Leptin concentrations in endometriosis: A systematic review and meta-analysis

INTRODUCTION

Endometriosis is an inflammatory condition, affecting mainly women of reproductive age. Leptin is a regulator of food intake and energy expenditure, posing pleiotropic actions, and regulating immunity and fertility. The aim of this study was to systematically review the literature regarding leptin concentrations in biological fluids and tissues of women with endometriosis, and to investigate and propose a possible role of leptin in the pathophysiology of endometriosis.

MATERIALS AND METHODS

A systematic search of the literature was conducted in two electronic databases (MEDLINE, COCHRANE) and grey literature for original research articles on humans, published in any language.

RESULTS

Twenty-nine studies with 1291 women with endometriosis and 1664 controls were included in the systematic review. Peritoneal fluid and follicular fluid leptin concentrations were higher in endometriosis compared with control group [mean difference (MD) 7.10, 95 % confidence interval (CI) 4.76 to 9.44 ng/mL, 18 studies), (MD 1.35, 95 % CI 0.54-2.17 ng/ml, 2 studies) respectively. No differences were evident in serum (MD 0.92, 95 % CI -0.84 to 2.68 ng/mL, 12 studies) or plasma (MD -0.95, 95 % CI -4.63 to 2.72 ng/mL, 3 studies) between the groups. No meta-analysis was conducted for ovarian tissue leptin (2 studies).

CONCLUSIONS

This meta-analysis provided evidence for increased leptin concentrations in both peritoneal fluid and follicular fluid of women with endometriosis compared with control; these differences were not present in the serum or plasma. The above results support a potential pathophysiologic role for leptin in the local microenvironment while declines its use as a blood diagnostic marker. Furthermore, we propose a possible role of leptin in the pathophysiology of endometriosis.

The Formidable yet Unresolved Interplay between Endometriosis and Obesity

Obesity and endometriosis are two very common entities, yet there is uncertainty on their exact relationship. Observational studies have repeatedly shown an inverse correlation between endometriosis and a low body mass index (BMI). However, obesity does not protect against endometriosis and on the contrary an increased BMI may lead to more severe forms of the disease. Besides, BMI is not accurate in all cases of obesity. Consequently, other anthropometric and phenomic traits have been studied, including body adiposity content, as well as the effect of BMI early in life on the manifestation of endometriosis in adulthood. Some studies have shown that the phenotypic inverse correlation between the two entities has a genetic background; however, others have indicated that certain polymorphisms are linked with endometriosis in females with increased BMI. The advent of metabolic bariatric surgery and pertinent research have led to the emergence of biomolecules that may be pivotal in understanding the pathophysiological interaction of the two entities, especially in the context of angiogenesis and inflammation. Future research should focus on three objectives: detection and interpretation of obesity-related biomarkers in experimental models with endometriosis; integration of endometriosis-related queries into bariatric registries; and multidisciplinary approach and collaboration among specialists.

Mental stress promotes the proliferation of endometriotic lesions in mice

Endometriosis is a condition in which tissue similar to the womb lining begins to grow in other sites, such as the ovaries or fallopian tubes. Endometriosis can cause pelvic pain, adhesion formation, and infertility. Here, we investigated the relationship between deterioration of endometriosis and inflammation of intraperitoneal adipose tissue in mice. We created a mouse model of endometriosis, then subjected these mice to stress loading. In the experimental mice, we measured protein expression levels of prostaglandin-E2, monocyte chemoattractant protein-1, and tumor necrosis factor-α using ELISA kits. We used quantitative real-time polymerase chain reaction to measure mRNA expression levels of inflammation-related enzymes and cytokines in lesions and adipose tissues. This study sugest that endometriotic lesions may progress in the presence of psychological stress in the presence of endometriosis. In addition, inflammation of the adipose tissue around the uterus may be involved in the development of endometriosis. However, this needs further consideration. Reducing or avoiding stress as much as possible may prevent the progression of endometriosis.

Effect of maternal body mass index on neonatal outcomes in women with endometriosis undergoing IVF

RESEARCH QUESTION

Does preconception body mass index (BMI) affect neonatal outcomes in women with endometriosis who conceive with IVF?

DESIGN

This retrospective study included 7086 women who delivered a singleton live birth through IVF between December 2006 and December 2017. Of these, 1111 women were diagnosed with endometriosis by laparoscopy or laparotomy, while 5975 women received IVF treatment due to tubal factor or male factor infertility. Women were categorized according to predefined BMI groups (<18.5 kg/m², BMI 18.5-24.9 kg/m², ≥25 kg/m²). All comparisons performed were between women undergoing cryopreserved embryo transfer.

RESULTS

After stratification by BMI, underweight women with endometriosis showed higher preterm birth (PTB) rates compared with controls (14.61% versus 3.28%, P < 0.001), whereas normal weight and overweight/obese endometriotic women had similar PTB rates to controls. There was a significant interactive effect of endometriosis and maternal BMI on preterm delivery (P for interaction <0.05). After adjustment for potential confounding factors, the PTB rate remained consistently higher in the low BMI subgroup of women with endometriosis (adjusted odds ratio 4.66, 95% confidence interval 2.54-8.57), whereas this difference was not observed for the other BMI categories. Additionally, we noted no differences in the rate of early PTB, low birthweight, macrosomia, small for gestational age and large for gestational age between women with endometriosis and controls with respect to any preconception category of BMI.

CONCLUSIONS

Endometriotic patients who were underweight before conception (BMI <18.5 kg/m²) had a higher rate of PTB than women without endometriosis, but the difference was not observed in the other BMI categories.

Therapeutic Efficacy of Palmitoylethanolamide and Its New Formulations in Synergy with Different Antioxidant Molecules Present in Diets

The use of a complete nutritional approach seems increasingly promising to combat chronic inflammation. The choice of healthy sources of carbohydrates, fats, and proteins, associated with regular physical activity and avoidance of smoking is essential to fight the war against chronic diseases. At the base of the analgesic, anti-inflammatory, or antioxidant action of the diets, there are numerous molecules, among which some of a lipidic nature very active in the inflammatory pathway. One class of molecules found in diets with anti-inflammatory actions are ALIAmides. Among all, one is particularly known for its ability to counteract the inflammatory cascade, the Palmitoylethanolamide (PEA). PEA is a molecular that is present in nature, in numerous foods, and is endogenously produced by our body, which acts as a balancer of inflammatory processes, also known as endocannabionoid-like. PEA is often used in the treatment of both acute and chronic inflammatory pathologies, either alone or in association with other molecules with properties, such as antioxidants or analgesics. This review aims to illustrate an overview of the different diets that are involved in the process of opposition to the inflammatory cascade, focusing on capacity of PEA and new formulations in synergy with other molecules.

Sulforaphane Attenuates Endometriosis in Rat Models Through Inhibiting PI3K/Akt Signaling Pathway

Sulforaphane exerts anti-inflammatory activity in inflammatory diseases. The endometriosis (EM) is accompanied by chronic inflammation. The present study aims to explore the therapeutic effects of sulforaphane on EM and its underlying mechanism. An EM rat model was established by transplantation of autologous fragments. The rats were intragastrically administered sulforaphane (5 mg/kg, 15 mg/kg, and 30 mg/kg) for 3 weeks. The volumes of endometriotic foci and adhesion score were calculated at the end of the experiment. Levels of interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and vascular endothelial growth factor (VEGF) were determined by enzyme-linked immunosorbent assay (ELISA). Expressions of VEGF, B-cell lymphoma/leukemia 2 (Bcl-2), Bax, cleaved caspase-3, PI3K, and Akt in endometrial tissue were determined by Western blotting. Relative expressions of PI3K and Akt were determined by quantitative polymerase chain reaction. Posttreatment of sulforaphane dose-dependently decreased the volumes of endometriotic foci and adhesion score in EM model. Additionally, posttreatment of sulforaphane inhibited levels of IL-6, IL-10, TNF-α, IFN-γ, and VEGF in peritoneal fluid and plasma. Posttreatment of sulforaphane regulated the expressions of VEGF, bcl-2, Bax, and cleaved Caspase-3 in EM model. The underlying mechanism revealed that sulforaphane attenuated EM in the rat model by inhibition of PI3K/Akt signaling pathway.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Non-coding RNAs in endometriosis: a narrative review

BACKGROUND

Endometriosis is a benign gynaecological disorder, which affects 10% of reproductive-aged women and is characterized by endometrial cells from the lining of the uterus being found outside the uterine cavity. However, the pathophysiological mechanisms causing the development of this heterogeneous disease remain enigmatic, and a lack of effective biomarkers necessitates surgical intervention for diagnosis. There is international recognition that accurate non-invasive diagnostic tests and more effective therapies are urgently needed. Non-coding RNA (ncRNA) molecules, which are important regulators of cellular function, have been implicated in many chronic conditions. In endometriosis, transcriptome profiling of tissue samples and functional in vivo and in vitro studies demonstrate that ncRNAs are key contributors to the disease process.

OBJECTIVE AND RATIONALE

In this review, we outline the biogenesis of various ncRNAs relevant to endometriosis and then summarize the evidence indicating their roles in regulatory pathways that govern disease establishment and progression.

SEARCH METHODS

Articles from 2000 to 2016 were selected for relevance, validity and quality, from results obtained in PubMed, MEDLINE and Google Scholar using the following search terms: ncRNA and reproduction; ncRNA and endometriosis; miRNA and endometriosis; lncRNA and endometriosis; siRNA and endometriosis; endometriosis; endometrial; cervical; ovary; uterus; reproductive tract. All articles were independently screened for eligibility by the authors.

OUTCOMES

This review integrates extensive information from all relevant published studies focusing on microRNAs, long ncRNAs and short inhibitory RNAs in endometriosis. We outline the biological function and synthesis of microRNAs, long ncRNAs and short inhibitory RNAs and provide detailed findings from human research as well as functional studies carried out both in vitro and in vivo, including animal models. Although variability in findings between individual studies exists, collectively, the extant literature justifies the conclusion that dysregulated ncRNAs are a significant element of the endometriosis condition.

WIDER IMPLICATIONS

There is a compelling case that microRNAs, long non-coding RNAs and short inhibitory RNAs have the potential to influence endometriosis development and persistence through modulating inflammation, proliferation, angiogenesis and tissue remodelling. Rapid advances in ncRNA biomarker discovery and therapeutics relevant to endometriosis are emerging. Unravelling the significance of ncRNAs in endometriosis will pave the way for new diagnostic tests and identify new therapeutic targets and treatment approaches that have the potential to improve clinical options for women with this disabling condition.

Leptin and Antioxidant Profile in Infertile Women with Endometriosis

Objective

To investigate the role of leptin hormone and oxidative stress in the pathogenesis of endometriosis among infertile women.

Methods

Blood samples and peritoneal fluid were collected from women undergoing laparoscopy. The study group included 24 infertile women with endometriosis, while 14 women with unexplained infertility represented the control group. Leptin hormone levels and three markers of antioxidants, including total antioxidant capacity (TAC), catalase (CAT) enzyme and superoxide dismutase (SOD) enzyme were estimated.

Results

Peritoneal fluid leptin concentrations were significantly higher in infertile endometriotic women compared with the control group. The levels of TAC, CAT and SOD were significantly lower in both serum and peritoneal fluid of infertile endometriotic women compared with controls. There was no significant difference in serum leptin concentrations between the studied groups.

Conclusions

Peritoneal leptin and oxidative stress may be an active factor in the pathogenesis and/or progression of endometriosis.

Decreased Cytotoxicity of Peripheral and Peritoneal Natural Killer Cell in Endometriosis

Endometriosis causes significant chronic pelvic pain, dysmenorrhea, and infertility and affects 10% of all women. In endometriosis, ectopic endometrium surviving after retrograde menstruation exhibits an abnormal immune response characterized by increased levels of activated macrophages and inflammatory cytokines. Particularly, dysfunctional natural killer (NK) cells play an important role in the pathogenesis of the disease by either facilitating or inhibiting the survival, implantation, and proliferation of endometrial cells. NK cells in the peritoneum and peritoneal fluid exhibit reduced levels of cytotoxicity in women with endometriosis. Several cytokines and inhibitory factors in the serum and peritoneal fluid also dysregulate NK cell cytotoxicity. Additionally, increased numbers of immature peripheral NK cells and induction of NK cell apoptosis are evident in the peritoneal fluid of women with endometriosis. The high rate of endometriosis recurrence after pharmaceutical or surgical treatment, which is associated with dysfunctional NK cells, indicates that new immunomodulatory management strategies are required. A good understanding of immune dysfunction would enable improvement of current treatments for endometriosis.

Leptin, its receptor and aromatase expression in deep infiltrating endometriosis

Background

The aim of this study was to evaluate the leptin levels in the serum and peritoneal fluid (PF) and the protein expression in three different peritoneal ectopic implants in patients who underwent surgery for deep infiltrating endometriosis.

Methods

All patients had been treated at the Department of Gynecology of the Pedro Ernesto University Hospital, Rio de Janeiro. The study group consisted of 15 patients who underwent surgery for adnexal masses and infertility, while the control group consisted of ten women who underwent surgery for tubal ligation. Peritoneal fluid and samples tissues were collected during surgery. Serum samples were obtained before anesthesia. In this study, the leptin levels in the serum and peritoneal fluid (PF) were evaluated by ELISA. The protein expression of leptin and its receptors (ObR) and aromatase enzyme were evaluated by Western blot analysis of the intestine, uterosacral ligament and vaginal septum in the ectopic implants. The t-test and one-way ANOVA with Holm-Sìdak post-test were used, and p < 0.05 was considered to be statistically significant.

Results

Compared to the controls, the serum leptin levels (control = 14.7 ng/mL ± 2.63, endometriosis = 19.2 ng/mL ± 1.84, p < 0.0001) were increased, while in PF, there was no difference (control = 6.68 ng/mL ± 0.43, endometriosis = 7.71 ng/mL ± 0.59, p = 0.18). Comparing women with and without ovarian implants, the leptin levels in both the serum and PF were significantly higher in women without ovarian implants (serum: with ovarian implant = 15.85 ± 1.99; without ovarian implant = 23.14 ± 2.60; ng/mL, p = 0.04; PF: with ovarian implant = 4.28 ± 1.30; without ovarian implant = 11.18 ± 2.98;ng/mL, p = 0.048). The leptin, ObR and aromatase protein expression levels were increased in lesions in the vaginal septum and were decreased in the intestine lesions.

Conclusion

This study reports several interesting associations between the leptin levels in serum, peritoneal fluid, and tissue samples and the localization of the ectopic endometrium. Although this study does not provide a clear picture of the role of leptin in the development and progression of peritoneal implants, it contributed new data that might be useful to elucidating the enigma that is the role of leptin in endometriosis disease.

Leptin promotes human endometriotic cell migration and invasion by up-regulating MMP-2 through the JAK2/STAT3 signaling pathway

Despite evidence that leptin may play a role in the pathogenesis of endometriosis, the specific function of leptin in the migration and invasion of endometriotic cells is not well characterized. In this study, we investigated the effect of leptin on the migration, invasion and matrix metalloproteinase (MMP) expression levels of human endometriotic cells. We found that leptin stimulated the migration and invasion of endometriotic cells (11Z, 12Z and 22B) in a dose-dependent manner. Leptin receptor (ObR) siRNA significantly inhibited the migration and invasion induced by leptin in 11Z and 12Z cells. Leptin-induced migration and invasion were significantly attenuated by pretreatment with SB-3CT, a specific gelatinase (MMP-2 and MMP-9) inhibitor. In addition, leptin-induced increases in the mRNA and protein expression and enzyme activity of MMP-2 in 11Z and 12Z cells. Selectively inhibiting MMP-2 using siRNA and an inhibitor (GM6003), impaired the ability of leptin to stimulate the migration and invasion of endometriotic cells, suggesting that MMP-2 plays an essential role in leptin-induced migration and invasion. Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) inhibitor (AG490) significantly inhibited the migration, invasion and MMP-2 expression induced by leptin in endometriotic cells. Furthermore, the Extracellular signal-Regulated Kinase inhibitor PD98059 neutralized the migration and invasion promoting effects of leptin. Taken together, these results suggest that leptin may contribute to the migration and invasion abilities of endometriotic cells via the up-regulation of MMP-2 through an ObR-dependent JAK2/STAT3 signaling pathway.

Predisposing factors to post-operative adhesion development

BACKGROUND

Adhesion development is the most common sequelae of intra-abdominal and pelvic surgery and represents a significant, yet poorly understood, cause of morbidity among post-operative patients. It remains unclear, for example, exactly why adhesions form more frequently in certain tissues and/or patients, or at specific locations within them, as opposed to others. This review contributes to the growing knowledge pool by elucidating factors that potentially predispose to the development of adhesions. Given the strong correlation between a hypofibrinolytic state and adhesion formation, this review article will examine not only those factors that have been shown to directly predispose to adhesion development, but also those that are likely do so indirectly by means of altering the coagulation/fibrinolytic profile.

METHODS

A literature search was performed using the PubMed database for all relevant English language articles up to February 2014. All of the identified articles were reviewed with particular attention to predisposing factors to post-operative adhesion development. In addition, the reference lists of each article were reviewed to identify additional relevant articles.

RESULTS

Various factors have been shown to directly increase the risk of post-operative adhesion development; namely, certain genetic polymorphisms in the interleukin-1 receptor antagonist, increased estrogen exposure, and endometriosis. In addition, numerous factors are known to increase the risk of fibrosis, therefore likely increasing the risk of adhesion development indirectly. These factors include genetic polymorphisms in plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor, diabetes mellitus, metabolic syndrome, hyperglycemia, obesity, depression, binge alcohol consumption, anti-Parkinsonian medications, oral hormone therapy, pregnancy, and cancer.

CONCLUSIONS

The literature reviewed in this paper will help to direct future research aimed at understanding the mechanisms that underlie the association of certain factors with adhesion development. This information will be crucial in the creation of adequate preventative and treatment strategies.

Pro-inflammatory cytokines for evaluation of inflammatory status in endometriosis

THE AIM OF THE STUDY

The aim of the study was to investigate the serum pro-inflammatory cytokine profile in patients with diagnosed endometriosis.

MATERIAL AND METHODS

The study included 160 women, who were divided in two study groups (Group I - endometriosis; Group 2 - healthy). We evaluated the serum levels of interleukin (IL)-1β, IL-5, IL-6, IL-7, and IL-12, and of tumour necrosis factor α (TNF-α) with the use of Human Multiplex Cytokine Panels.

RESULTS

The serum level of IL-1β, IL-6, and TNF-α is significantly higher in women with endometriosis compared to women free of disease, from the control group (mean 10.777, 183.027, and 131.326, respectively, compared to 3.039, 70.043, and 75.285, respectively; p = 0.002, p < 0.001, and p = 0.015, respectively). No significant differences in the serum levels of IL-5 and IL-12 were observed between the studied groups, and IL-7 had a very low detection rate.

CONCLUSIONS

Women with endometriosis have elevated levels of key pro-inflammatory cytokines, i.e. IL-1β, IL-6, and TNF-α. At the same time, IL-1β and IL-6 could be used as predictors for endometriosis.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Evaluation of selected angiogenic and inflammatory markers in endometriosis before and after danazol treatment

Angiogenesis and inflammation are pivotal processes in developing endometriosis in the peritoneal cavity. The aim of the present study was to evaluate these two processes in women with endometriosis who had been treated with danazol to determine the sensitivity of a non-invasive test in diagnosing endometriosis. The clinical follow-up study was conducted in a group of 103 women diagnosed laparoscopically with endometriosis. Thirty-five patients qualified for danazol treatment. Pain was assessed using a visual analogue scale, whereas endometriosis was assessed using the revised American Society of Reproductive Medicine (rASRM) scale. Cancer antigen (CA)-125 and C-reactive protein (CRP) concentrations in plasma and peritoneal fluid were determined by immunoenzymatic methods, whereas vascular endothelial growth factor (VEGF) and interleukin (IL)-1β concentrations in plasma and peritoneal fluid were determined by ELISA. Endometrial expression of IL-8 and platelet-derived growth factor alpha polypeptide (PDGF-A) was determined using real-time polymerase chain reaction (PCR). Women with endometriosis (68.9% of patients) had higher plasma concentrations of CA-125, as well as higher concentrations of both CA-125 and VEGF in the peritoneal fluid. Endometrial expression of IL-8 mRNA was significantly higher, whereas that of PDGF-A was significantly lower, in contrast. After danazol treatment the patients reported lower pain scores; in addition, CA-125 concentrations in the plasma were decreased (P<0.001), whereas VEGF concentration in the plasma increased (P=0.009). For the diagnosis of endometriosis, none of the combinations of given markers had a sensitivity >60%. Danazol treatment is highly effective in relieving pain and decreasing CA-125 concentrations in the plasma. Higher plasma concentrations of VEGF after treatment could imply stimulation of angiogenesis.

Expression of adiponectin, leptin, and their receptors in ovarian endometrioma

OBJECTIVE

To evaluate the expression of leptin, leptin receptor (ObR), adiponectin, and adiponectin receptor (AdipoR) in ovarian endometriomas compared with normal endometrium, and to analyze relationships among adipokines and their receptors.

DESIGN

Experimental study.

SETTING

A clinic for the treatment of endometriosis and basic research laboratories.

PATIENT(S)

Forty-four women with endometriosis and 42 age-matched women with no laparoscopic evidence of endometriosis as control subjects.

INTERVENTION(S)

Endometrial tissue samples were obtained during laparoscopic surgery.

MAIN OUTCOME MEASURE(S)

Immunohistochemical staining for leptin, ObR, adiponectin, and AdipoR was performed with the use of tissue microarray. Clinical characteristics were reviewed from the patient's medical records. The effect of leptin on the expression of adiponectin was evaluated in endometriotic cell line using real-time reverse-transcription polymerase chain reaction.

RESULT(S)

Positive expression rates of leptin and ObR were significantly higher in ovarian endometrioma compared with normal endometrium, but those of adiponectin and AdipoR were similar (ovarian endometrioma vs. normal endometrium, respectively: leptin 100% vs. 59.5%; ObR 72.7% vs. 33.3%; adiponectin 31.8% vs. 42.9%; AdipoR 88.6% vs. 73.8%). Expression of adipokines and their receptors did not show any correlation with disease stage. A positive correlation was found between expression of ObR and adiponectin (correlation coefficient 0.488; P=.001). Leptin treatment in endometriotic cells induced mRNA expression of adiponectin.

CONCLUSION(S)

These data suggest that leptin and its receptor are induced in ovarian endometriomas, and that the leptin/ObR system regulates adiponectin gene expression in endometriotic cells.

Diagnostic accuracy of interleukin-6 levels in peritoneal fluid for detection of endometriosis

PURPOSE

To determine, with extended receiver operating characteristic (ROC) curve analysis, the diagnostic value of cytokines showing significantly different peritoneal concentrations between women with and without endometriosis.

METHODS

Multiplex cytokine concentration measurement of IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ levels in peritoneal fluid of women with minimal to mild (n = 10) and moderate to severe (n = 26) endometriosis, and 42 controls.

RESULTS

Only IL-6 and IL-10 concentrations were significantly higher in endometriosis patients than in controls. Specifically, significantly higher IL-6 and IL-10 levels were found in moderate to severe but not in minimal to mild endometriosis as compared to controls. For evaluation of diagnostic significance, ROC analysis determined discriminating parameters for IL-6, while those calculated for IL-10 were useless. Importantly, ROC analysis for IL-6 levels limited to women with moderate to severe endometriosis showed the highest area under the curve with the sample size sufficient to achieve 90 % power of the test. Finally, extended ROC including cost of analysis for this group of patients determined the optimal cut-off leading to high specificity and positive likelihood ratio resulting in 79 % effectiveness of the test.

CONCLUSIONS

While our outcomes show moderate usefulness of peritoneal IL-6 levels in discrimination of moderate to severe endometriosis, further studies might be needed to determine the usefulness of peritoneal IL-6 levels in detection of early stages of endometriosis, as such a finding would be more relevant in clinical decision making.

Gene expression of leptin and long leptin receptor isoform in endometriosis: a case-control study

In this study, leptin/BMI ratio in serum and peritoneal fluid and gene expression of leptin and long form leptin receptor (OB-R_L) were assessed in eutopic and ectopic endometria of women with endometriosis and controls. Increased serum leptin/BMI ratio was found in endometriosis patients. Leptin and OB-R_L gene expression was significantly higher in ectopic versus eutopic endometrium of patients and controls. A positive, significant correlation was observed between leptin and OB-R_L transcripts in ectopic endometria and also in eutopic endometria in endometriosis and control groups. A negative and significant correlation was found between OB-R_L mRNA expression and peritoneal fluid leptin/BMI ratio only in endometriosis. These data suggest that, through a modulatory interaction with its active receptor, leptin might play a role in the development of endometrial implants.

The adjuvant use of N-palmitoylethanolamine and transpolydatin in the treatment of endometriotic pain

OBJECTIVE

To test the adjuvant use of the combination of N-palmitoylethanolamine and transpolydatin in the medical treatment of endometriotic pain.

STUDY DESIGN

We enrolled 47 patients admitted to the Outpatient Endometriosis Care Unit of Ferrara University from January 2011 to December 2011. They were divided into two groups according to the endometriosis site (group A: recto-vaginal septum; group B: ovary). One tablet, containing 400 mg of micronized N-palmitoylethanolamine plus 40 mg transpolydatin, was administered twice daily on a full stomach for 90 days. Each patient was requested to grade the severity of dysmenorrhea, chronic pelvic pain, dyspareunia and dyschezia using a 0-10 cm visual analogic scale prior to beginning treatment (T0), after 30 days (T1), 60 days (T2) and 90 days (T3). The continuous and categorical variables were compared, respectively, using Student's t-test and the chi-square test. Analysis of variance for repeated measures was used to verify the reduction of endometriotic pain.

RESULTS

The intensity of endometriotic pain decreased significantly for both groups (p<0.0001). The efficacy of drug treatment was significant after 30 days. Pain intensity decreased equally in the two groups except for dysmenorrhea, which was reduced more rapidly in group B.

CONCLUSIONS

The combination of N-palmitoylethanolamine and transpolydatin reduced pain related to endometriosis irrespective of lesion site. It had a marked effect on chronic pelvic pain determined by deep endometriosis and on dysmenorrhea correlated to ovarian endometriosis.

Plasma adipokines and endometriosis risk: a prospective nested case-control investigation from the Nurses' Health Study II

STUDY QUESTION

Do higher leptin levels and lower adiponectin levels predict subsequent development of endometriosis?

SUMMARY ANSWER

Plasma leptin and adiponectin levels were not associated with laparoscopically confirmed endometriosis when collected prior to disease diagnosis.

WHAT IS KNOWN ALREADY

Case-control studies have identified altered levels of the inflammatory adipokines leptin and adiponectin in women with endometriosis, but it remains unclear whether inflammation results in endometriosis or whether the presence of endometriosis creates an inflammatory state.

STUDY DESIGN, SIZE, DURATION

Nested, matched, case-control study within the prospective Nurses' Health Study II (NHS II) cohort. Blood samples were collected between 1996 and 1999 from 29 611 female nurses within the cohort. Women who reported endometriosis before blood collection were excluded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Plasma leptin and adiponectin levels were assayed by ELISA. Three hundred and fifty cases of laparoscopically confirmed endometriosis were matched 1:2 with 694 controls of comparable race, age, infertility history, menopausal status and time of blood draw. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression models adjusting for matching factors and BMI.

MAIN RESULTS AND THE ROLE OF CHANCE

After adjusting for BMI, there were no statistically significant associations between endometriosis and leptin [RR = 1.2; 95% CI = 0.7-2.0; P-value, test for linear trend (P(trend)) = 0.72], adiponectin (RR = 0.8; 95% CI = 0.5-1.2; P(trend) = 0.48) or the leptin to adiponectin ratio (RR = 0.8; 95% CI = 0.4-1.4; P(trend) = 0.14) when comparing the upper with the lower quartile. Results were unaltered when analyses were stratified by BMI or restricted to cases diagnosed ≥ 4 years after blood draw. To evaluate statistical significance and limit the role of chance to the gold standard of 5%, we present 95% CIs about the RRs, and for P-values calculated for linear tests of trend and tests of heterogeneity, we have set the α-level to be 0.05 (i.e. <0.05 is considered to be statistically significant).

LIMITATIONS AND REASONS FOR CAUTION

A limitation of this study is the inability to differentiate the time of endometriosis 'diagnosis' from the time of disease 'onset' due to the impossibility in identifying a precise time point at which the disease process was first initiated at a molecular or cellular level. Additional limitations include lack of information regarding stage of endometriosis and the possibility of asymptomatic disease in the control population.

WIDER IMPLICATIONS OF THE FINDINGS

The mean age at diagnosis of endometriosis in the study population is 41.7, ≈ 10 years older than the mean age of diagnosis in the general population. While this may limit the generalizability of the results, there is no reason to suspect that the association between adipokines and endometriosis risk should differ at a younger age of diagnosis in an adult population.

Peritoneal cytokines and adhesion formation in endometriosis: an inverse association with vascular endothelial growth factor concentration

OBJECTIVE

To evaluate inflammatory/angiogenic cytokines-interleukin-1β (IL-1β), IL-6, IL-8, IL-12, interferon-γ (IFN-γ), tumor necrosis factor (TNF), and vascular endothelial growth factor A (VEGF-A)-in the peritoneal fluid of patients with endometriosis in relation to the occurrence and severity of pelvic adhesions and in control women without pelvic pathology.

DESIGN

Case-control study.

SETTING

University research institution and hospital.

PATIENT(S)

Sixty-five women with laparoscopically and histopathologically confirmed endometriosis, including 40 women with pelvic adhesions, and 37 control women without pelvic pathology.

INTERVENTION(S)

Peritoneal fluid aspirated during routine diagnostic laparoscopic examination.

MAIN OUTCOME MEASURE(S)

Cytokines evaluated in the peritoneal fluid via specific enzyme-linked immunosorbent assays.

RESULT(S)

Endometriosis and the revised American Fertility Society score of this disease were associated with statistically significantly increased levels of peritoneal IL-6 and IL-8 whereas the incidence and score of endometriosis-related pelvic adhesions were negatively associated with increased levels of VEGF-A. Notably, the concentration of VEGF-A predicted adhesion development and severity after adjustment for endometriosis severity. The adhesion score also correlated with increased levels of IL-6; however, after adjustment for endometriosis severity, the effect of this cytokine was no longer statistically significant.

CONCLUSION(S)

Increased levels of VEGF-A may be associated with a decreased rate of pelvic adhesion formation in the course of endometriosis.

Expression of ghrelin and its receptors in ovarian endometrioma

Endometriosis is a common gynaecological disorder manifesting by implantation and growth of endometrial tissue outside the uterine cavity. The evidence accumulates that endometriosis may be associated with abrogated regulation of energy balance. Ghrelin is one of the most important orexigenic factor which may also play a role in regulation of inflammatory and angiogenic reactions. The present study was aimed at investigating expression profile of ghrelin and its receptors (GHSR1α and GHSR1β) in endometriotic lesions. The study included ovarian cysts and peritoneal fluid specimens obtained laparoscopically from 20 women with revised American Fertility Society stage III or IV endometriosis. Expression of specific mRNAs was assessed by reverse transcription-polymerase chain reaction. Expression of ghrelin and GHSR1α protein was studied by immunohistochemical staining with specific antibodies. Ghrelin and its receptors mRNA expression was found in all tested specimens. Specific mRNAs for these factors were also expressed in the peritoneal leukocytes. Immunohistochemical staining revealed expression of ghrelin and GHSR1α both in glandular endometrioid epithelium and in some stromal cells, particularly in some fibroblasts, blood vessels and infiltrating leukocytes. Co-localization of ghrelin and its receptors strongly suggests that this neuropeptide may affect development and growth of endometriotic lesions and may influence local inflammatory and angiogenic response.

Deep infiltrating endometriosis is associated with markedly lower body mass index: a 476 case-control study

BACKGROUND

An inverse association between BMI and endometriosis has been reported but remains controversial. We decided to evaluate the association between BMI and the different types of endometriosis, classified as superficial endometriosis (SUP), deep infiltrating endometriosis (DIE) and ovarian endometrioma (OMA).

METHODS

From a prospective database of patients who underwent gynecological surgery between February 2005 and October 2008, we compared 238 patients with a histological diagnosis of endometriosis to 238 age- and smoking-status-matched controls using a prospective preoperative questionnaire and surgical data. Numerical variables means were compared for matched pairs, and non-parametric variables using Wilcoxon test. The Odds ratios for all types of endometriosis adjusted for confounding variables were computed according to predefined BMI groups [1(<18.5), 2 (≥18.5 and <22), 3(≥22 and <25), 4(≥25)], taking Group 3 as the reference population.

RESULTS

BMI was significantly lower for all 238 patients (21.70 ± 3.7 versus 23.29 ± 4.1, P < 0.001), for 101 OMA patients (21.88 ± 3.8 versus 22.99 ± 4, P < 0.038), and for 97 DIE patients (21.35 ± 3.4 versus 23.35 ± 3.8, P < 0.001) compared with their own controls, but not for the 40 SUP patients. Patients in Group 1 had adjusted odds ratios as high as 3.3 [95% confidence interval (CI): 1.6-6.8] for DIE and 2.7 (95% CI: 1.1-6.8) for OMA; in Group 2, the adjusted oddd ratios were 2.6 (95% CI: 1.3-5.5) for DIE and 2.9 (95% CI: 1.5-5.4) for OMA.

CONCLUSIONS

Endometriotic patients have lower BMI than age- and smoking-status-matched controls, independent of confounding variables. Patients with the lowest BMI (<18.5) are at a high risk of DIE.

Effectiveness of the association micronized N-Palmitoylethanolamine (PEA)-transpolydatin in the treatment of chronic pelvic pain related to endometriosis after laparoscopic assessment: a pilot study

OBJECTIVE

Aim of our study was to evaluate the effectiveness of the association between N-Palmitoylethanolamine and transpolydatin in the management of chronic pelvic pain related to EMS.

STUDY DESIGN

This was a randomized, double-blind, parallel-group, placebo-controlled clinical trial involving 61 subjects, submitted to a first line laparoscopic conservative surgery, who were randomized into 3 groups receiving: group A (n=21) the association N-Palmitoylethanolamine-transpolydatin 400 mg + 40 mg twice a day for 3 months; group B (n=20) the placebo for 3 months; group C (n=20) a single course of Celecoxib 200mg twice a day for 7 consecutive days. Assessments of the severity of pelvic endometriosis (pelvic pain, dysmenorrhoea and dyspareunia) were recorded before and after treatment on a questionnaire and a 10-point VAS. Differences between groups were verified with Kruskal-Wallis ANOVA for non-parametric multiple comparisons.

RESULTS

A marked decrease in dysmenorrhoea, dyspareunia and pelvic pain was observed in all groups, and the association between N-Palmitoylethanolamine and transpolydatin resulted to be more effective than placebo (P<.001). Additionally, the treatment with Celecoxib resulted in a decrease in pelvic pain more effective either than the association N-Palmitoylethanolamine and transpolydatin or placebo.

CONCLUSION

These preliminary results show that the association between micronized N-Palmitoylethanolamine and transpolydatin is effective in the management of pelvic pain related to endometriosis after laparoscopy. Additionally, this association seems to be safe, shows an optimal control of pain and can be used in patients who are unable to receive other therapies.

Peritoneal fluid leptin levels are increased but adiponectin levels are not changed in infertile patients with pelvic endometriosis

OBJECTIVE

Endometriosis is a leading cause of infertility, and recent studies suggest that leptin and adiponectin may have a role in its causation and progression. This study assessed levels of leptin and adiponectin in serum and peritoneal fluid (PF) in patients with endometriosis and infertility.

DESIGN AND SETTING

This cross-sectional study included women undergoing diagnostic and/or therapeutic laparoscopy for endometriosis with chief complaint of infertility. Following laparoscopy, patients diagnosed with endometriosis served as cases while patients with no endometriosis served as controls. Patients with polycystic ovarian syndrome, diabetes, thyroiditis and patients on prior therapy with danazol or leuprolide were excluded from the study. Leptin and adiponectin levels were analysed in blood and PF using commercially available ELISA kits.

RESULTS

Of the 50 patients (aged 22-41 years), 15 had endometriosis (cases) while 35 had no endometriosis (controls). The median PF leptin level was significantly higher in cases as compared to controls (27.7 vs. 15.6 ng/ml, p = 0.019), and this remained significant even when PF leptin was BMI-normalised (p = 0.004). However, median serum leptin and adiponectin levels remained comparable between the two groups.

CONCLUSIONS

This study confirmed the role of PF leptin in causation and progression of endometriosis. However, this would have been definitive if healthy fertile females were included in this study.

The peritoneal leptin, MCP-1 and TNF-α in the pathogenesis of endometriosis-associated infertility

PROBLEM

To explore the roles of leptin, monocyte chemotactic protein (MCP)-1, and tumour necrosis factor (TNF)-α in the peritoneal fluid (PF) in the pathogenesis of endometriosis-associated infertility.

METHOD OF STUDY

Leptin, MCP-1, and TNF-α levels in the PF from 28 infertile women with endometriosis (study group), 23 women with fallopian-associated infertility (controls), and 24 women with myoma (controls) were determined by performing enzyme-linked immunosorbent assay (ELISA).

RESULT

Leptin and TNF-α levels in the PF showed no significant difference among three groups. The MCP-1 level in patients with endometriosis was higher than those in fallopian-associated infertility group and myoma group (P < 0.01). There was a positive correlation between leptin and MCP-1 levels in the PF of patients with endometriosis (P < 0.05).

CONCLUSION

Peritoneal leptin and MCP-1 play important roles in the pathogenesis of infertility in the early stage of endometriosis.

Role of leptin in the activation of immune cells

Adipose tissue is an active endocrine organ that secretes various humoral factors (adipokines), and its shift to production of proinflammatory cytokines in obesity likely contributes to the low-level systemic inflammation that may be present in metabolic syndrome-associated chronic pathologies such as atherosclerosis. Leptin is one of the most important hormones secreted by adipocytes, with a variety of physiological roles related to the control of metabolism and energy homeostasis. One of these functions is the connection between nutritional status and immune competence. The adipocyte-derived hormone leptin has been shown to regulate the immune response, innate and adaptive response, both in normal and pathological conditions. The role of leptin in regulating immune response has been assessed in vitro as well as in clinical studies. It has been shown that conditions of reduced leptin production are associated with increased infection susceptibility. Conversely, immune-mediated disorders such as autoimmune diseases are associated with increased secretion of leptin and production of proinflammatory pathogenic cytokines. Thus, leptin is a mediator of the inflammatory response.