Immunobiology of endometriosis

Stress During Development of Experimental Endometriosis Influences Nerve Growth and Disease Progression

PURPOSE

We have previously shown that stress prior to induction worsens clinical presentation and inflammatory parameters in a rat model of endometriosis. This study was designed to examine whether stress during the development of endometriosis can affect the growth of endometriotic implants through nerve growth and immune alterations.

METHODS

Endometriosis was surgically induced in female Sprague-Dawley rats by suturing uterine horn implants onto the small intestine mesentery. Two weeks later, one group of rats (endo-stress) was subjected to a 10-day swim stress protocol. Controls had no stress (endo-no stress) or sutures only and stress (sham-stress). On day 60, all rats were killed and examined for the presence of endometriotic vesicles. The size of each vesicle was measured. The uterus and colon were removed and assessed for damage, cell infiltration, and expression of nerve growth factor (NGF), its receptors (p75 and Tropomyosin receptor kinase A (Trk-A)/pTrk-A), and calcitonin gene-related peptide, a sensory fiber marker. A differential analysis of peritoneal fluid white blood cell count was performed.

RESULTS

Stress significantly increased endometriotic vesicle size but not colonic damage and increased infiltration of mast cells. Significantly increased expression of NGF and its receptors was found in the uterus of animals with endometriosis receiving stress.

CONCLUSIONS

Stress stimulates the development of ectopic endometrial vesicles in an animal model of endometriosis and increases inflammatory cell recruitment to the peritoneum. In addition, stress promotes nerve fiber growth in the uterus.

Platelets impair natural killer cell reactivity and function in endometriosis through multiple mechanisms

Study question

Do platelets have any role in the reduced cytotoxicity of natural killer (NK) cells in endometriosis?

Summary answer

Platelets impair NK cell reactivity and function in endometriosis through multiple mechanisms.

What is known already

Platelets play an important role in the development of endometriosis, and platelet-derived transforming growth factor-β1 (TGF-β1) suppresses the expression of NK Group 2, Member D (NKG2D) on NK cells, resulting in reduced cytotoxicity in women with endometriosis.

Study design size, duration

Experiments on mice with induced endometriosis in which either platelets, NK cells or both were depleted and controls (none depleted). In vitro experiments with NK cells, platelets and, as target cells, endometriotic epithelial cell and endometrial stromal cell lines.

Participants/materials setting methods

Immunohistochemistry analysis of ectopic endometrial tissues from mice with induced endometriosis receiving either platelet depletion (PD), NK cell depletion, or both or none. Immunofluorescence, flow cytometry and gene expression analysis for major histocompatibility complex class I (MHC-I) expression in target cells. Cytotoxicity and degranulation assays and the measurement of interferon (IFN)-γ secretion for the evaluation of NK cytotoxicity. Flow cytometry and gene expression for the expression of NK cell receptors.

Main results and the role of chance

PD resulted in significantly reduced lesion weight in mice with induced endometriosis, but NK cell depletion as well as concomitant platelet and NK cell depletion increased the weight, suggesting that the anti-endometriosis effect of PD is mediated, at least in part, by increased NK cell cytotoxicity against endometriotic cells. Co-incubation of target cells with platelets resulted in rapid platelet coating as well as increased MHC-I expression in these cells, effectively providing a cloak of 'pseudo-self' to these cells to shield against NK cell lysis. It also reduced the expression of NKG2D ligands MICA and MICB and reduced the NK cell cytotoxicity. In addition, co-incubation of NK cells with platelets impaired the NK cell cytotoxicity as well. This impaired NK cell cytotoxicity was not due to the increased NK cell apoptosis, but, rather, through reduced NK cell degranulation and IFN-γ production, and reduced expression of activating receptors NKG2D and NKp46 and increased expression of inhibitory receptor KIR2DL1 in NK cells. Inhibition of TGF-β1 signaling partially restored the aberrant expression of NKG2D, NKp46 and KIR2DL1, and partially restored the impaired NK cell cytotoxicity induced by activated platelets and their releasate.

Large scale data

Not applicable.

Limitations reasons for caution

This study is confined by the limitation of animal and in vitro experimentation and the lack of direct human data.

Wider implications of the findings

Anti-platelet treatment holds promise in treating endometriosis.

Study funding/competing interests

The National Natural Science Foundation of China (81471434 to S.W.G., 81270676 to S.W.G., 81370695 to X.S.L. and 81671436 to X.S.L). None of the authors has anything to disclose.

Bradykinin system is involved in endometriosis-related pain through endothelin-1 production

BACKGROUND

Endometriosis is a gynaecological disease exhibiting severe pelvic pain, but the mechanism of pain production remains unknown. Bradykinin (BK) is known as an inflammatory mediator, and shows elevated levels in inflammatory diseases such as rheumatoid arthritis. In the present study, we evaluated whether BK is involved in endometriosis-related pain.

METHODS

Endometriotic lesions were used for immunohistochemistry. Primary cultures of endometriotic stromal cells (ESC) were stimulated with IL-1β and/or BK. Quantitative RT-PCR was used to evaluate the mRNA expressions of BK receptors (BKR) and endothelin-1 in ESC. The concentration of endothelin-1 in cystic fluid of endometrioma or non-endometrioma was measured with ELISA. The conditioned medium of ESC stimulated with IL-1β and/or BK was injected intraplantarly in mice, and evaluated whether pain-related licking behaviour was elicited.

RESULTS

The expressions of BK and BKR in endometriotic lesions were observed by immunohistochemistry. In vitro experiments showed that IL-1β induced BKR-B1 and B2 on ESC. Activation of these receptors by BK significantly induced endothelin-1 expression in ESC, which was negated completely by HOE-140, a BKR-B2 antagonist. The cystic fluid of endometrioma contained higher amount of endothelin-1 compared to non-endometrioma. Intraplantar injection of the conditioned medium of ESC treated with IL-1β and BK significantly induced licking behaviour, which was suppressed with BQ-123, an endothelin type-A receptor antagonist.

CONCLUSIONS

The present study demonstrated the presence and the function of the BK axis in endometriosis, and established a potential new therapy target for endometriosis-related pain.

SIGNIFICANCE

The present study demonstrated (1) the presence and the function of the BK system in endometriosis, (2) activation of BKR induced endothelin-1 in endometriotic lesion and (3) blocking endothelin-1 was effective to decrease pain.

Decreased zinc and increased lead blood levels are associated with endometriosis in Asian Women

Endometriosis is an inflammatory disease associated with multiple pathogenic factors and studies regarding roles of trace metals in endometriosis have been inconsistent and limited. The aim of this cross-sectional study was to compare the blood levels of miscellaneous trace metals measured by inductively coupled plasma mass spectrometry in infertile women with and without endometriosis. Zinc level is associated with declining odds (adjusted OR=0.39, 95% CI=0.18-0.88) of endometriosis. By contrast, lead level is associated with increasing odds (adjusted OR=2.59, 95% CI=1.11-6.06) of endometriosis. The cadmium levels were higher in women with endometriosis, but the aOR was not significant. Zinc has anti-inflammatory characteristics and regulates homeostasis of zinc-containing superoxide dismutase. High lead levels might induce reactive oxygen species and deplete antioxidant defense mechanisms. Further prospective study is needed to test for their causal associations.

The role of the B lymphocytes in endometriosis: A systematic review

The physiopathology of endometriosis is not completely understood and its progression is associated with a local and systemic inflammatory reaction. It is important to clarify the potential role of the immune system to better understand its implication in the pathogenesis of endometriosis, which includes the study of the role of B cells and antibodies. The aim of this study was to review the literature about the role of B lymphocytes in endometriosis. A search for "endometriosis", "B cells" and "B lymphocytes" in databases resulted in 140 citations; after applying inclusion and exclusion criteria, a total of 22 studies were assessed. The analyzed samples in the studies varied and different markers and techniques were used by the authors to evaluate the direct or indirect role of B lymphocytes in endometriosis. Most studies demonstrated increased number and/or activation of B cells while seven studies found no difference and two studies showed decreased number of B cells. Increased B lymphocytes and excessive production of autoantibodies in endometriosis have been described in the literature, but their role in the development of the disease is not well understood. Moreover, the association of these factors with clinical symptoms, location and severity of the disease has not been investigated. Further studies are necessary to clarify the role of B cells in the development of endometriosis and propose new therapeutic strategies such as the use of drugs that target these cells.

A mixture of St. John's wort and sea buckthorn oils regresses endometriotic implants and affects the levels of inflammatory mediators in peritoneal fluid of the rat: A surgically induced endometriosis model

OBJECTIVE

Sea buckthorn (Hippophae rhamnoides L.) and St. John's wort (Hypericum perforatum L.) are used as an emmenagog and for the treatment of other gynecological disorders including uterus inflammation and endometriosis. The aim of the present study is to investigate the potential of a mixture of sea buckthorn and St. John's wort oils (HrHp oil) in the treatment of endometriosis.

MATERIALS AND METHODS

The activity was assessed in surgically induced endometriosis in rats. A 15-mm piece of endometrium was sutured into the abdominal wall. Twenty-eight days later, a second laparotomy was performed to calculate the endometrial foci areas and to score intra-abdominal adhesions. The rats were treated with either vehicle, HrHp oil formulation, or the reference (buserelin acetate). At the end of the experiment all rats were sacrificed and endometriotic foci areas and intra-abdominal adhesions were re-evaluated. The tissue sections were analyzed histopathologically. Peritoneal fluids of the experimental animals were collected in order to detect the levels of tumor necrosis factor-α, vascular endothelial growth factor, and interleukin-6, which might be involved in the etiology of endometriosis.

RESULTS

In the HrHp oil-treated group, the volumes of endometriotic implants were found to be significantly decreased (from 50.8 mm³ to 18.6 mm³, p<0.001) without any adhesion (0.0±0.0, p<0.001) when compared to the control group (3.1±0.9). The levels of tumor necrosis factor-α decreased from 7.02±1.33 pg/mL to 4.78±1.02 pg/mL (p<0.01); vascular endothelial growth factor from 17.39±8.52 pg/mL to 9.67±5.04 pg/mL (p<0.01); and interleukin-6 from 50.95±22.84 pg/mL to 29.11±7.45 pg/mL (p<0.01), respectively, after HrHp oil treatment.

CONCLUSION

HrHp oil may be a promising alternative for the treatment of endometriosis.

Increased expression of resistin in ectopic endometrial tissue of women with endometriosis

PROBLEM

Inflammation is a key process in the establishment and progression of endometriosis. Resistin, an adipocytokine, has biological properties linked to immunologic functions, but its role in endometriosis is unclear.

METHOD OF STUDY

Resistin gene expression was examined in eutopic and ectopic endometrial tissues from women with (n=25) or without (n=25) endometriosis. Resistin mRNA and protein levels were determined in endometrial tissue using quantitative real-time reverse transcription PCR and Western blotting, following adipokine profiling arrays.

RESULTS

Resistin protein was detected in human endometrial tissues using an adipokine array test. Resistin mRNA and protein levels were significantly higher in ectopic endometrial tissue of patients with endometriosis than in normal eutopic endometrial tissue.

CONCLUSION

Our results indicate that resistin is differentially expressed in endometrial tissues from women with endometriosis and imply a role for resistin in endometriosis-associated pelvic inflammation.

Periodontal disease and women's health

BACKGROUND

Periodontal disease (PD) is a multifactorial inflammatory condition in which inappropriate interaction between the host immune response and specific groups of bacterial pathogens leads to destruction of connective and bone tissues supporting the tooth. Dissemination of pathogens, toxins, and immune complexes from and to periodontal lesions is at the basis of the increasingly recognized association between PD and various systemic diseases (SDs). Considering the growing attention of the medical community to "gender medicine", this review focuses on the association between PD and six systemic conditions heavily impacting women's health, with the aim of providing evidence in support of a joint effort between physicians and dentists to improve clinical management of these conditions.

METHODS

We considered systematic reviews, meta-analyses and narrative reviews evaluating all possible associations between periodontitis, systemic diseases and women.

RESULTS

Gender prevalence for PD is discordant, but the literature strongly supports an association between PD and female infertility and adverse pregnancy outcomes. Moreover, PD is bidirectionally linked to several systemic diseases characterized by an established female gender bias, i.e. osteoporosis (OP), cardiovascular diseases (CVD), autoimmunity, Alzheimer's disease (AD) and cancer.

CONCLUSIONS

Overall, the literature data reviewed here provides a strong foundation for further characterization of molecular and microbial drivers of PD and of several female-prevalent systemic diseases, highlighting the possible importance of a good oral condition in preventing or attenuating women's systemic diseases.

Prevalence, Clinical and Laparoscopic Features of Endometriosis Among Infertile Women

OBJECTIVE

To study the prevalence, clinical and laparoscopic characteristics of endometriosis in infertile women.

STUDY DESIGN

This is a hospital-based prospective study.

PATIENTS

Five hundred and two (502) patients underwent diagnostic laparoscopy for evaluation of cause for infertility. Staging of endometriosis was done according to the rAFS scoring system.

RESULTS

Out of 502 women, 276 (54.98 %) showed the presence of endometriosis, while 226 (45.01 %) did not have endometriosis. One hundred and eighty-three (66.3 %) women had stage I endometriosis, 49 (17.77 %) had stage II, 23 (8.33 %) had stage III and 21 (7.6 %) had stage IV endometriosis.

CONCLUSION

More than 50 % of patients in our study were asymptomatic; however, the presence of menorrhagia, dysmenorrhoea, dyspareunia and chronic pelvic pain are also clinically statistically significant. So, we would like to recommend the evaluation and treatment of a patient reporting in gynaecological OPD with the above-mentioned complaints with high suspicion of endometriosis.

Resveratrol and endometriosis: In vitro and animal studies and underlying mechanisms (Review)

Endometriosis is characterized by the existence of endometrial tissue and stroma exterior to the uterus. Despite the high prevalence, the etiology of endometriosis remains elusive. The search for the most promising compounds for treatment of endometriosis has led to the identification of resveratrol. Resveratrol, a plant-derived polyphenolic phytoalexin, demonstrates broad-spectrum health beneficial effects, including anti-proliferative, anti-inflammatory, antineoplastic and antioxidant. Because of these properties and its wide distribution in plants, resveratrol is proposed as a great potential to treat endometriosis. In animal models of endometriosis, resveratrol supplementation has displayed beneficial results as it decreased the number and volume of endometrial implants, suppressed proliferation, vascularization, inflammation, cell survival and increased apoptosis. On the other hand, resveratrol treatment in-vitro studies, reduced invasiveness of endometriotic stromal cells (ESCs) and suppressed their inflammatory responses. In this review, we will summarize the recent studies in in-vitro and animal studies on resveratrol and endometriosis.

Ovarian endometriosis and vitamin D serum levels

AIM

The aim of this study was to assess the vitamin D serum level in women with ovarian endometriosis; specifically, a possible correlation between the dimensions of ovarian endometriomas and vitamin D serum levels was evaluated.

MATERIALS AND METHODS

This was an observational study of childbearing-age women diagnosed with singleton ovarian endometrioma from January 2015 to December 2015. Women diagnosed with multiple ovarian endometriomas or extraovarian endometriosis were excluded.

RESULTS

Forty-nine women constituted the initial study cohort. In these women, the mean (±SD) 25-OH-D3 serum level was 22.0 (±8.9) ng/ml, and 42 of them (85.7%) were diagnosed with hypovitaminosis D. In the "hypovitaminosis D women", the mean (± SD) diameter of ovarian endometriomas was 40.2 ± 22.6 mm, while in the "normal vitamin D serum level women" it was 26.7 ± 12.1 mm (p = 0.1). However, a significant linear correlation between 25-OH-D3 serum level and the diameter of ovarian endometriomas was found (r = -0.3, p = 0.03).

CONCLUSION

We found a relatively high rate of women with ovarian endometriosis and hypovitaminosis D. Interestingly, a significant linear correlation between 25-OH-D3 serum levels and the diameter of ovarian endometrioma emerged.

Co-culture with macrophages enhances the clonogenic and invasion activity of endometriotic stromal cells

OBJECTIVE

To study the effect on endometrial and endometriotic cells after co-culture with macrophages, using clonogenic, invasion and self-renewal assays.

MATERIALS AND METHODS

Peripheral blood samples, endometrium and endometriotic tissues were collected. Autologous macrophages were co-cultured with endometrial and endometriotic cells. The number of colony-forming units (CFU), invasiveness and self-renewal activity after co-culture with macrophages were determined. The cytokine level of colony-stimulating factor-1 (CSF-1) from macrophages with and without endometriosis was compared.

RESULTS

Co-culture with macrophages significantly increased the clonogenic and invasion ability of endometriotic stromal cells in vitro. Colony-stimulating factor-1 (CSF-1) was up-regulated in endometriotic macrophages conditioned medium when compared to those without the disease.

CONCLUSIONS

These data suggest that macrophages may increase the proliferation and invasion activity of stromal clonogenic cells in women with endometriosis.

A 10-Year Study of Endometriosis in an Indigenous Black African Population

Background

Endometriosis is a debilitating disease in women of child-bearing age.

Objective

To describe the pattern of presentation, stage of endometriosis and biophysical profile of patients with endometriosis.

Method

A retrospective study of 61 consecutive infertile patients between June 2003 and November 2014.

Results

The means (±SD) of age (years) and of body mass index (BMI) (kg/m2) of the patients were 34.1 (4.3) and 25.8 (5.0), respectively. A relatively high percentage (43, 70.5%) of the women were in the age range of 31-40 years; had normal BMI (27, 44.3%); were nulliparous (53, 86.9%) and were of primary infertility (40, 65.6%). The mean (±SD) age at menarche, of cycle length, of the duration of flow and of years trying to conceive were 12.9 (1.7) years, 29.1 (2.7) days, 4.7 (1.1) days and 5.2 (3.8) years, respectively. A high proportion of them (37, 60.7%) presented with severe endometriosis. The main symptoms at presentation was dysmenorrhea (47, 73.8%). Of the 32 (52.5%) with associated utero-tubal factor, 20 (62.5%) were in severe stage of endometriosis. Among women with endometriosis, those with primary infertility were over three times more likely to present with menorrhagia than those with secondary infertility (χ² = 4.70; p value = 0.03; OR = 3.33; 95% CI = 1.10, 10.12). Only 3 (4.9%) had diagnosis of endometriosis in first-degree relative. Dysmenorrhea was a strong predictor of severe endometriosis.

Conclusions

There may be some trends in the biophysical profile of infertile women with endometriosis which may influence diagnosis and management.

A Western Primer of Chinese Herbal Therapy in Endometriosis and Infertility

Endometriosis is a disease that affects approximately 10% of all reproductive-aged women and the prevalence rises to 20–50% in infertile women. There is growing evidence that medicinal Chinese herbs with pain-alleviating and anti-inflammatory properties may be useful in the treatment of endometriosis and infertility, but the mechanisms of action of these herbs have yet to be investigated. In addition, studies of adequate design, sample size and appropriate control are lacking. Therefore, prospective randomized, controlled studies to evaluate the efficacy, mechanism of action and toxicities of Chinese herbs in the treatment endometriosis and infertility are needed.

Surgery accelerates the development of endometriosis in mice

BACKGROUND

Surgery is currently the mainstay treatment for solid tumors and many benign diseases, including endometriosis, and women tend to receive substantially more surgeries than men mainly because of gynecological and cosmetic surgeries. Despite its cosmetic, therapeutic, or even life-saving benefits, surgery is reported to increase the cancer risk and promotes cancer metastasis. Surgery activates adrenergic signaling, which in turn suppresses cell-mediated immunity and promotes angiogenesis and metastasis. Because immunity, angiogenesis, and invasiveness are all involved in the pathophysiology of endometriosis, it is unclear whether surgery may accelerate the development of endometriosis.

OBJECTIVE

The objective of the study was to test the hypothesis that surgery activates adrenergic signaling, increases angiogenesis, and accelerates the growth of endometriotic lesions.

STUDY DESIGN

This was a prospective, randomized experimentation. The first experiment used 42 female adult Balb/C mice, and the second used 90 female adult Balb/C mice. In experiment 1, 3 days after the induction of endometriosis, mice were randomly divided into 3 groups of approximately equal sizes, control, laparotomy, and mastectomy. In experiment 2, propranolol infusion via Alzet pumps was used to forestall the effect of sympathetic nervous system activation by surgery. In both experiments, mice were evaluated 2 weeks after surgery. Lesion size, hotplate latency, and immunohistochemistry analysis of vascular endothelial growth factor, CD31-positive microvessels, proliferating cell nuclear antigen, phosphorylated cyclic adenosine monophosphate-responsive element-binding protein, β2-adrenergic receptor (ADRB)-2, ADRB1, ADRB3, ADRA1, and ADRA2 in ectopic implants.

RESULTS

Both mastectomy and laparotomy increased lesion weight and exacerbated hyperalgesia, increased microvessel density and elevated the immunoreactivity against ADRB2, phosphorylated cyclic adenosine monophosphate-responsive element-binding protein, vascular endothelial growth factor, and proliferating cell nuclear antigen but not ADRB1, ADRB3, ADRA1, and ADRA2, suggesting activated adrenergic signaling, increased angiogenesis, and accelerated growth of endometriotic lesions. β-Blockade completely abrogated the facilitory effect of surgery, further underscoring the critical role of β-adrenergic signaling in mediating the effect of surgery.

CONCLUSION

Surgery activates adrenergic signaling, increases angiogenesis, and accelerates the growth of endometriotic lesions in the mouse, but such a facilitory effect of surgery can be completely abrogated by β-blockade. Whether surgery can promote the development of endometriosis in humans warrants further investigation.

Apoptosis and Differential Expression of Apoptosis-Related Proteins in Endometriotic Glandular and Stromal Cells

OBJECTIVE

Apoptosis is an important regulator of eutopic endometrial function. Endometriosis, the growth of endometrial tissue outside the uterus, could result from increased cellular proliferation or decreased apoptosis in response to appropriate stimuli. The objective of this study was to evaluate the rate of apoptosis and the expression of apoptosis-related Bcl-2 and Bax proteins in endometriotic tissues within the glandular and stromal compartments, according to the phase of the menstrual cycle and the stage of disease.

METHODS

Ovarian endometriosis samples were evaluated in 75 women who had surgery at a university hospital. Apoptotic cells were detected with the use of the dUTP nick-end labeling (TUNEL) assay. Bcl-2 and Bax expression were assessed by immunohistochemical techniques.

RESULTS

The percentage of apoptotic cells was significantly higher in endometriotic stromal cells (73.3%) compared with glandular cells (48%; P =.002). In contrast, the expression of the apoptosis-related proteins Bcl-2 and Bax was significantly lower in the endometriotic stroma (17.3% for both) than in the glandular epithelium (38.6% and 41.3%, respectively; P <.004). No significant menstrual cycle phase-dependent changes or endometriosis stage-related changes were observed in TUNEL, Bcl-2, or Bax positivity within ovarian endometriotic tissues.

CONCLUSION

Apoptosis occurs in ovarian endometriotic lesions at significantly higher levels in the stroma than the glandular epithelium. However, Bcl-2 and Bax proteins are distributed preferentially in glandular epithelial cells. The apoptotic rate as well as Bcl-2 and Bax expression in ovarian endometriotic cells were not affected by the stage of endometriosis or the phase of the menstrual cycle.

Niclosamide As a Potential Nonsteroidal Therapy for Endometriosis That Preserves Reproductive Function in an Experimental Mouse Model

Endometriosis causes severe chronic pelvic pain and infertility. Because the standard medication and surgical treatments of endometriosis show high recurrence of symptoms, it is necessary to improve current treatment options. In the initial study, we examined whether niclosamide can be a useful drug for endometriosis in a preclinical setting. Endometriotic implants were induced using an established mouse model involving transimplantation of mouse endometrial fragments to the peritoneal wall of recipient mice. When the recipient mice were treated with niclosamide for 3 weeks, niclosamide reduced the size of endometriotic implants with inhibition of cell proliferation, and inflammatory signaling including RELA (NFKB) and STAT3 activation, but did not alter expression of steroid hormone receptors. To identify genes whose expression is regulated by niclosamide in endometriotic implants, RNA-sequencing was performed, and several genes downregulated by niclosamide were related to inflammatory responses, WNT and MAPK signaling. In a second study designed to assess whether niclosamide affects reproductive function, the recipient mice started receiving niclosamide after the induction of endometriosis. Then, the recipient mice were mated with wild type males, and treatments continued until the pups were born. Niclosamide treated recipient mice became pregnant and produced normal size and number of pups. These results suggest that niclosamide could be an effective therapeutic drug, and acts as an inhibitor of inflammatory signaling without disrupting normal reproductive function.

Immune-inflammation gene signatures in endometriosis patients

OBJECTIVE

To determine if the molecular profiles of endometriotic lesions contain informative measures of inflammation and immune dysfunction that may contribute to better understanding of the interplay between immune dysfunction and inflammation and their contribution to endometriosis pathogenesis.

DESIGN

Immune and inflammation transcriptomic analysis with the use of the Nanostring nCounter GX Human Immunology V2 platform (579 human immune and inflammation-related genes and 15 housekeeping genes).

SETTING

Academic university and teaching hospital.

INTERVENTION(S)

None.

PATIENT(S)

Stage III-IV endometriosis patients with infertility (n = 8) and fertile disease-free control women undergoing tubal ligation (n = 8). Menstrual stage was matched to secretory phase in all participants.

MAIN OUTCOME MEASURE(S)

Immune and inflammation transcriptomics quantification from ectopic endometriotic lesions and matched eutopic endometrium from patients. Endometria of fertile women served as control subjects.

RESULT(S)

Our results displayed endometriotic lesions as molecularly distinct entities compared with eutopic endometrium and endometrium of control samples; 396 out of 579 screened immune and inflammation-related genes were significantly different in ectopic tissues compared with control endometrium. Most importantly, eutopic endometrium of the patients displayed a unique molecular profile compared with the control endometrium (91/579 genes were significantly different), particularly of genes involved in regulation of cell apoptosis and decidualization.

CONCLUSION(S)

We characterize differential expression of immune-inflammation genes in endometriosis patients, and show molecular distinction of eutopic endometrium of patients compared with control fertile women.

Metabolomics Reveals Altered Lipid Metabolism in a Mouse Model of Endometriosis

Endometriosis is a common chronic estrogen-dependent gynecological disease affecting 10% of women in their reproductive age. It is characterized by proliferation of functional endometrial glands and stroma outside the uterine cavity. In the present study, we used mass spectrometry-based lipidomics to investigate the alterations in serum lipid profiles of mice induced with endometriosis. We identified several dysregulated lipids such as phosphatidylcholines, sphingomyelins, phosphatidylethanolamines, and triglycerides and show that triglycerides may be due to a general inflammatory condition in the peritoneum. We also show that in addition to phosphatidylcholine alteration, there is also an effect in the ratio of phosphatidylcholine/phosphatidylethanolamine in serum of mice induced with the disease and that this change may be due to increased expression of the phosphatidylethanolamine N-methyltransferase gene. The study provides new insight into the etiology of endometriosis.

Increased percentage of Th17 cells in peritoneal fluid is associated with severity of endometriosis

AIM

Th17 cells are a newly discovered T helper lymphocyte subpopulation, producing interleukin IL-17. Th17 cells are present in blood and peritoneal fluid (PF) at different stages of endometriosis. We aim to establish their potential importance in the pathogenesis and clinical features of the disease.

METHODS

The percentage of Th17 cells among T helper lymphocytes was determined in the PF and peripheral blood (PB) of patients with endometriosis and in the control group by flow cytometry using monoclonal antibodies: anti-CD-4-FITC, anti-CD-3-PE/Cy5, and anti-IL-17A-PE.

RESULTS

Th17 percentage is increased in PF in comparison with PB in both endometriotic patients and in the control group. In severe endometriosis, the percentage of Th17 cells in PF was higher than with early (I/II stage) endometriosis. A positive correlation between the percentage of Th17 cells in PF and the white blood cell count in PB was found in patients with endometriosis.

CONCLUSION

Targeting the activity of PF Th17 cells may have an influence on the proliferation of ectopic tissue and clinical manifestations of the disease.

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.

Hyaluronic acid reagent functional chitosan-PEI conjugate with AQP2-siRNA suppressed endometriotic lesion formation

To identify a new drug candidate for treating endometriosis which has fewer side effects, a new polymeric nanoparticle gene delivery system consisting of polyethylenimine-grafted chitosan oligosaccharide (CSO-PEI) with hyaluronic acid (HA) and small interfering RNA (siRNA) was designed. There was no obvious difference in sizes observed between (CSO-PEI/siRNA)HA and CSO-PEI/siRNA, but the fluorescence accumulation in the endometriotic lesion was more significant for (CSO-PEI/siRNA)HA compared with CSO-PEI/siRNA due to the specific binding of HA to CD44. In addition, the (CSO-PEI/siRNA)HA nanoparticle gene therapy significantly decreased the endometriotic lesion sizes with atrophy and degeneration of the ectopic endometrium. The epithelial cells of ectopic endometrium from rat models of endometriosis showed a significantly lower CD44 expression than control after treatment with (CSO-PEI/siRNA)HA. Furthermore, observation under an electron microscope showed no obvious toxic effect on the reproductive organs. Therefore, (CSO-PEI/siRNA)HA gene delivery system can be used as an effective method for the treatment of endometriosis.

Increased Risk of Endometriosis in Patients With Lower Genital Tract Infection: A Nationwide Cohort Study

Endometriosis results from the ectopic invasion of endometrial glands and stroma in the peritoneal cavity. The exact etiology of endometriosis is still unknown. It has, however, been shown that there are higher numbers of Escherichia coli in menstrual blood, and higher endotoxin levels in menstrual fluid, as well as, in the peritoneal fluid of patients with endometriosis. In this study, we aimed to determine whether lower genital tract infections could increase the risk of endometriosis.We used the Taiwan National Health Insurance database to conduct a population-based cohort study. We included patients diagnosed with inflammatory diseases of the cervix, vagina, and vulva, and a control group comprising patients matched by age, sex, and comorbidities but without inflammatory diseases of the cervix, vagina, or vulva.A total of 79,512 patients were included in the inflammatory disease group and an equal number of control individuals were selected. The incidence of endometriosis (hazard ratio, 2.01; 95% confidence interval, 1.91-2.12; P < 0.001) was higher among patients than controls. Cox proportional hazards models showed that irrespective of comorbidities, lower genital tract infection was an independent risk factor for endometriosis.Patients with lower genital tract infections exhibit a substantially higher risk for developing endometriosis.

Cystic Endometriosis in a Huge Degenerated Subserous Leiomyoma Mimicking Bilateral Multicystic Endometriomas in an Infertile Woman with Diminished Ovarian Reserve: A Rare Endometriotic Implantation

Uterine leiomyomas are the most common pelvic tumor in women. Leiomyoma can show atypical locations and degenerations and may not be easily differentiated from adnexal masses. Uterine leiomyoma can undergo cystic degeneration and is said to be found in 4% of all types of degenerations. The commonest type of degeneration is hyaline seen in 60% of patients. Usually uterine leiomyoma does not present as clinical and radiological diagnostic challenge. However, when leiomyoma undergoes massive cystic degeneration they may become clinical and radiological diagnostic dilemmas. The MRI showed a huge cystic mass protruding up to the pelvis not differentiated from bilateral endometriomas and accompanying subserous myomas. Surgery revealed that the mass is not bilateral endometriomas but a huge pedunculated leiomyoma with cystic degeneration and cystic endometriosis. Endometriosis is a troubling gynecologic condition occurring in 10% to 15% of women of reproductive age and is associated with fertility problems. As a peritoneal disease, the locations of endometriotic lesions are predominantly the ovaries (96.4%), followed by the soft tissue (2.8%), gastrointestinal tract (0.3%), and urinary tract (0.2%) and other rare locations. The presented case is multiple sized cystic endometriosis (endometriomas) located in a huge pedunculated subserous leiomyoma in an infertile woman having a history of laparoscopic bilateral endometrioma surgery. Conclusion. To our knowledge, this is the first reported case for endometriotic cysts (endometriomas) located in a huge cystic degenerated leiomyoma. PubMed search revealed no report concerning endometriotic implantation in the leiomyomas.

Pathophysiology of Endometriosis: Role of High Mobility Group Box-1 and Toll-Like Receptor 4 Developing Inflammation in Endometrium

Oxidative stress has been proposed as a potential factor associated with the establishment and progression of endometriosis. Although a few studies have shown possible mechanisms which may play roles in development, progression of endometriosis, few are known in regards of initiation of the disease, especially in the relationship with endometrium. The aim of our study was to investigate whether normal endometrium may be changed by Damage-associated molecular patterns (DAMPs), which may contribute developing pathologic endometrium to induce endometriosis. Endometrial tissues were obtained from 10 patients with fibroids undergoing hysterectomy at a university hospital. High mobility group box-1 (HMGB-1), which is a representative DAMP, has been chosen that may induce alteration in endometrium. In preceding immunohistochemistry experiments using paraffin-block sections from endometriosis (N = 33) and control (N = 27) group, retrospectively, HMGB-1 expression was shown in both epithelial and stromal cell. HMGB-1 expression was significantly increased in secretory phase of endometriosis group, comparing to the controls. To examine the alteration of endometrial stromal cell (HESC) by oxidative stress in terms of HMGB-1, cell proliferation and expression of its receptor, TLR4 was measured according to recombinant HMGB-1 use. Cell proliferation was assessed by CCK-8 assay; real-time PCR and western blotting were used to quantify Toll like receptor 4 (TLR4) mRNA and protein expression respectively. A TLR4 antagonist (LPS-RS) and an inhibitor of the NF-κB pathway (TPCA-1, an IKK-2 inhibitor) were used to confirm the relationships between HMGB-1, TLR4, and the NF-κB pathway. Passive release of HMGB-1 was significantly proportional to the increase in cell death (P<0.05). HESCs showed significant proliferation following treatment with rHMGB-1 (P<0.05), and increased TLR4 expression was observed following rHMGB-1 treatment (P<0.05) in a concentration-dependent manner. Treatment with a TLR4 antagonist and an NF-κB inhibitor resulted in suppression of rHMGB-1-induced HESC proliferation (P<0.05). Levels of IL-6 were significantly decreased following treatment with an NF-κB inhibitor (P<0.05). Our results support the development of altered, pathological endometrium resulted from oxidative stress in normal endometrium. These findings may provide important insights into the changes in endometrium linking the development and progression of endometriosis.

Endometriosis and systemic lupus erythematosus: a population-based case-control study

OBJECTIVE

To investigate the association between endometriosis and systemic lupus erythematosus (SLE) in prospectively collected population-based data.

METHODS

We conducted a case-control study using Swedish registers, identifying female SLE cases from the National Patient Register and female controls sampled from the general population matched on birth year, sex and county during 1964-2011. We identified endometriosis diagnoses from the National Patient Register using ICD codes. We estimated odds ratios and 95% confidence intervals using conditional logistic regression models.

RESULTS

We identified 2834 cases of SLE and 14,164 controls. Seventy-eight cases were diagnosed with endometriosis prior to their SLE diagnosis and 288 controls were diagnosed prior to the index date. We observed a significant association between endometriosis and subsequent SLE with an odds ratio of 1.39 (95% confidence interval = 1.09-1.78). The association was similar when requiring a laparoscopy/laparotomy within six months of the endometriosis diagnosis (odds ratio = 1.33; 95% confidence interval = 0.84-2.12) while the association was stronger when restricted to endometriosis diagnosed at the same time as hysterectomy (odds ratio = 2.26; 95% confidence interval = 1.47-3.64).

CONCLUSIONS

Our findings suggest an association between endometriosis and SLE. Future prospective studies with extended follow-up will be necessary to clarify whether this association is influenced by the timing and severity of endometriosis diagnosis.

Concurrent, Prospective, Analytical Cohort Study of Endometriosis Patients at Latifa Hospital – Dubai, UAE

Objective

To analyze the prevalence and features of endometriosis in a targeted group of population in the United Arab Emirates (UAE).

Methods

A prospective study of 247 patients with endometriosis who attended the specialty clinic for endometriosis, Latifa Hospital from September 2012 to May 2015. All patients underwent surgical treatment. All patients filled out a preoperative questionnaire that included demographic data, clinical presentation, chief complaint, prior treatment, and personal, obstetric, and family history. Confirmation of endometriosis was carried out intraoperatively with/without conclusive histopathology of endometriosis. Epidemiological analysis of patients with confirmed endometriosis was done, as compared to published international data of the same category.

Results

The prevalence of endometriosis in our study was 4.2%. UAE nationals made up 57.9% (143) of endometriosis sufferers and 42.1% (104) were expatriates. A total of 2.8% (7) were adolescents (14-20), 35.8% (88) were in the early reproductive age group (20-30), 47.3% (117) in the mid-age group (30-40), 13.3% (33) in late reproductive age group (40-50), and 0.8% (2) in postmenopausal age group. 56.6% (140) were P-0, 17% (42) P-1, and 26.4% (65) P-2 or more. Primary infertility was shown in 22.2% (55) of patients and 15.3% (38) had secondary infertility. There were 44.5% (110) of patients with a normal BMI index, 2.8% (7) underweight, 31.9% (79) overweight, and 20.6% (51) were obese. Regarding the type of endometriosis, patients were divided into three groups, those with ovarian endometriosis 49.8% (123), pelvic endometriosis 42.2% (104), and other, mainly adenomyosis 8% (20). The stages of endometriosis were 17.2% (42) with stage I, 44.5% (110), with stage II, 32.4% (80) with stage III, and 5.8% (14) with stage IV. In our study 19.4% had a family history of endometriosis while in 72.1% there was no family history.

Conclusions

This was the first ever epidemiological study in the UAE among patients with a confirmed diagnosis of endometriosis. There is need for further epidemiological surveys to obtain a more realistic view of the prevalence and severity of the disease in UAE patients with endometriosis who, however, do seem to share the same incidence rate and features as reported worldwide.

GnRH and GnRH receptors in the pathophysiology of the human female reproductive system

BACKGROUND

Human reproduction depends on an intact hypothalamic-pituitary-gonadal (HPG) axis. Hypothalamic gonadotrophin-releasing hormone (GnRH) has been recognized, since its identification in 1971, as the central regulator of the production and release of the pituitary gonadotrophins that, in turn, regulate the gonadal functions and the production of sex steroids. The characteristic peculiar development, distribution and episodic activity of GnRH-producing neurons have solicited an interdisciplinary interest on the etiopathogenesis of several reproductive diseases. The more recent identification of a GnRH/GnRH receptor (GnRHR) system in both the human endometrium and ovary has widened the spectrum of action of the peptide and of its analogues beyond its hypothalamic function.

METHODS

An analysis of research and review articles published in international journals until June 2015 has been carried out to comprehensively summarize both the well established and the most recent knowledge on the physiopathology of the GnRH system in the central and peripheral control of female reproductive functions and diseases.

RESULTS

This review focuses on the role of GnRH neurons in the control of the reproductive axis. New knowledge is accumulating on the genetic programme that drives GnRH neuron development to ameliorate the diagnosis and treatment of GnRH deficiency and consequent delayed or absent puberty. Moreover, a better understanding of the mechanisms controlling the episodic release of GnRH during the onset of puberty and the ovulatory cycle has enabled the pharmacological use of GnRH itself or its synthetic analogues (agonists and antagonists) to either stimulate or to block the gonadotrophin secretion and modulate the functions of the reproductive axis in several reproductive diseases and in assisted reproduction technology. Several inputs from other neuronal populations, as well as metabolic, somatic and age-related signals, may greatly affect the functions of the GnRH pulse generator during the female lifespan; their modulation may offer new possible strategies for diagnostic and therapeutic interventions. A GnRH/GnRHR system is also expressed in female reproductive tissues (e.g. endometrium and ovary), both in normal and pathological conditions. The expression of this system in the human endometrium and ovary supports its physiological regulatory role in the processes of trophoblast invasion of the maternal endometrium and embryo implantation as well as of follicular development and corpus luteum functions. The GnRH/GnRHR system that is expressed in diseased tissues of the female reproductive tract (both benign and malignant) is at present considered an effective molecular target for the development of novel therapeutic approaches for these pathologies. GnRH agonists are also considered as a promising therapeutic approach to counteract ovarian failure in young female patients undergoing chemotherapy.

CONCLUSIONS

Increasing knowledge about the regulation of GnRH pulsatile release, as well as the therapeutic use of its analogues, offers interesting new perspectives in the diagnosis, treatment and outcome of female reproductive disorders, including tumoral and iatrogenic diseases.

Ovarian damage due to cyst removal: a comparison of endometriomas and dermoid cysts

INTRODUCTION

Surgical treatment of endometriomas and potential damage to the ovary have been debated. Studies have described the inconsistent risk of unintended removal of ovarian tissue when a cystectomy of an endometrioma is performed. We evaluated the risk of inadvertently removed ovarian tissue during surgery by comparing specimens of endometriomas and dermoid cysts removed laparoscopically.

MATERIAL AND METHODS

The material included 326 women in a retrospective cohort study at Rigshospitalet, University hospital in Copenhagen, Denmark from 2011 to 2013. Surgery was performed laparoscopically for 393 benign cysts with a diagnosis of either endometrioma (n = 294) or dermoid cyst (n = 99). The microscopic existence of ovarian tissue in the cystectomy specimens were compared and correlation between CA 125 and size of cysts was examined.

RESULTS

In total, 80.3% endometrioma cystectomies disclosed ovarian stroma compared with 17.2% of the resected dermoid cysts (p < 0.001). The difference was found despite skilled laparoscopic surgeons performing the procedure in the endometriosis cohort. A significant positive correlation between the size of endometriomas and the value of CA 125 was found (p < 0.009).

CONCLUSION

The risk of removal of ovarian tissue during laparoscopic surgery is significantly higher for endometriomas than for dermoid cysts.

TGF-βI Regulates Cell Migration through Pluripotent Transcription Factor OCT4 in Endometriosis

Transforming growth factor (TGF-β)/TGF-β receptor signal is known to promote cell migration. Up-regulation of TGF-β in serum/peritoneal fluid and increased levels of pluripotent transcription factor OCT4 in endometriotic tissues are frequently observed in patients with endometriosis. However, the mechanisms underlying how TGF-β/TGF-β receptor and OCT4 affect endometriotic cell migration still remain largely unknown. Therefore, endometriotic tissue with high cell migratory capacity were collected from patients with adenomyotic myometrium (n = 23) and chocolate cyst (n = 24); and endometrial tissue with low cell migratory capacity in normal endometrium or hyperplastic endometrium (n = 8) were collected as the controls. We found the mRNA levels of TGF-β receptor I (TGF-β RI) and OCT4 were significantly higher in the high-migratory ectopic endometriotic tissues than those of the low-migratory normal or hyperplastic endometrium. Positive correlations between TGF-β RI and OCT4, and either TGF-β RI or OCT4 with migration-related genes (SNAIL, SLUG and TWIST) regarding the mRNA levels were observed in human endometriotic tissues. TGF-βI dose-dependently increased the gene and protein levels of OCT4, SNAIL and N-Cadherin (N-CAD) and silencing of endogenous OCT4 significantly suppressed the TGF-βI-induced expressions of N-CAD and SNAIL in primary human endometriotic stromal cells and human endometrial carcinoma cell lines RL95-2 and HEC1A. Furthermore, TGF-βI significantly increased the migration ability of endometriotic cells and silencing of OCT4 dramatically suppressed the TGF-βI-induced cell migration activity evidenced by wound-closure assay, transwell assay, and confocal image of F-actin cellular distribution. In conclusion, the present findings demonstrate that the niche TGF-β plays a critical role in initiating expressions of pluripotent transcription factor OCT4 which may contribute to the ectopic endometrial growth by stimulating endometrial cell migration. These findings would be useful for developing therapeutic strategies targeting TGF-β-OCT4 signaling to prevent endometriosis in the future.

High temperature requirement A1, transforming growth factor beta1, phosphoSmad2 and Ki67 in eutopic and ectopic endometrium of women with endometriosis

Increasing evidence supports the hypothesis that TGFb1 signalling may be mediated by high temperature requirement A1 (HtrA1) serine protease, acting on important regulatory mechanisms such as cell proliferation and mobility. Evidence is now accumulating to suggest that HtrA1 is involved in the development and progression of several pathologies. The aim of this study was to evaluate: i) if HtrA1 and TGFb1 expressions differ in eutopic and ectopic endometrium in women with endometriosis; ii) if HtrA1 correlates to TGFb1, pSmad and Ki67. This study was carried out including 10 women with ovarian endometriosis (cases) and 10 women with non endometriotic diseases (controls). Endometrial tissue underwent immunohistochemical H-score analysis for HtrA1, TGFb1, pSmad and Ki67 molecules. Data evaluation was performed by a nonparametric Kruskal-Wallis test and Spearman correlation was applied to evaluate the relationship among the molecules investigated in the epithelial and in the stromal compartment. The HtrA1 was significant decreased in ectopic and eutopic endometrium of women with endometriosis when compared with control endometrium in epithelial compartment. TGFb1was significantly increased in eutopic endometrium and decreased in ectopic endometrium in epithelial and stromal compartment. In addition, Ki67 was significant increased and an increase, but not significant, was detected for pSMAd2 in eutopic and ectopic endometrium compared to control one.  In summary, the significant direct correlation between TGFb1 and pSmad2 as well as between HtrA1 and TGFb1 and the very significant increase of Ki67 in stromal compartment of eutopic endometrium suggest a possible involvement of HtrA1 in the pathogenesis of endometriosis.

Cathepsin Protease Inhibition Reduces Endometriosis Lesion Establishment

Endometriosis is a gynecologic disease characterized by the ectopic presence of endometrial tissue on organs within the peritoneal cavity, causing debilitating abdominal pain and infertility. Current treatments alleviate moderate pain symptoms associated with the disorder but exhibit limited ability to prevent new or recurring lesion establishment and growth. Retrograde menstruation has been implicated for introducing endometrial tissue into the peritoneal cavity, but molecular mechanisms underlying attachment and invasion are not fully understood. We hypothesize that cysteine cathepsins, a group of powerful extracellular matrix proteases, facilitate endometrial tissue invasion and endometriosis lesion establishment in the peritoneal wall and inhibiting this activity would decrease endometriosis lesion implantation. To test this, we used an immunocompetent endometriosis mouse model and found that endometriotic lesions exhibited a greater than 5-fold increase in active cathepsins compared to tissue from peritoneal wall or eutopic endometrium, with cathepsins L and K specifically implicated. Human endometriosis lesions also exhibited greater cathepsin activity than adjacent peritoneum tissue, supporting the mouse results. Finally, we tested the hypothesis that inhibiting cathepsin activity could block endometriosis lesion attachment and implantation in vivo. Intraperitoneal injection of the broad cysteine cathepsin inhibitor, E-64, significantly reduced the number of attached endometriosis lesions in our murine model compared to vehicle-treated controls demonstrating that cathepsin proteases contribute to endometriosis lesion establishment, and their inhibition may provide a novel, nonhormonal therapy for endometriosis.