Potential involvement of iron in the pathogenesis of peritoneal endometriosis

The aim of this study is to review the current literature associating endometriosis with iron and to discuss the potential causes and consequences of iron overload in the pelvic cavity. Indeed, iron is essential for all living organisms. However, excess iron can result in toxicity and is associated with pathological disorders. In endometriosis patients, iron overload has been demonstrated in the different components of the peritoneal cavity (peritoneal fluid, endometriotic lesions, peritoneum and macrophages). Animal models allow us to gather essential information on the origin, metabolism and effect of iron overload in endometriosis, which may originate from erythrocytes carried into the pelvic cavity mainly by retrograde menstruation. Peritoneal macrophages play an important role in the degradation of these erythrocytes and in subsequent peritoneal iron metabolism. Iron overload could affect a wide range of mechanisms involved in endometriosis development, such as oxidative stress or lesion proliferation. In conclusion, excess iron accumulation can result in toxicity and may be one of the factors contributing to the development of endometriosis. Treatment with an iron chelator could thus be beneficial in endometriosis patients to prevent iron overload in the pelvic cavity, thereby diminishing its deleterious effect.     

Characterization of iron deposition in endometriotic lesions induced in the nude mouse model

BACKGROUND: Pelvic endometriotic lesions are often laden with hemosiderin. In order to investigate the potential source of such iron deposits, we examined whether the seric and erythrocyte fractions of menstrual effluent might influence the occurrence of iron deposition within lesions in a murine model of endometriosis. METHODS: Endometriosis was induced in 57 nude mice by intraperitoneal injection of unfractionated human menstrual effluent, endometrial fragments plus serum, endometrial fragments plus erythrocytes or endometrial cell fraction alone. The number of implants, histologic aspect, proliferative activity and iron deposition in lesions was assessed. RESULTS: On day 5, lesions were evidenced in all 10 mice receiving menstrual effluent, in 9/13 of those injected with the cellular fraction, in 10/13 with the cellular fraction plus serum and in 10/12 with the cellular fraction plus erythrocytes. Iron conglomerates were observed at the interface between the lesion and peritoneum when menstrual effluent (47 deposits/mm(2)) and the cellular fraction with erythrocytes (20 deposits/mm(2)) were injected, but were scarce when the cellular fraction was injected without erythrocytes, either alone (4 deposits/mm(2)) or with serum (2 deposits/mm(2)) (P < 0.05). CONCLUSIONS: Iron conglomerates, typically found in the stroma of endometriotic lesions, were induced by erythrocytes present in menstrual effluent. This may be one of the factors triggering oxidative damage and chronic inflammation.     

Tumour necrosis factor alpha concentrations in the peritoneal fluid of infertile women with minimal or mild endometriosis are lower in patients with red lesions only than in patients without red lesions

Tumour necrosis factor alpha (TNFalpha) of peritoneal fluid is believed to have important pro-inflammatory and angiogenic activities in the complex mechanisms of development of peritoneal endometriotic lesions. We have evaluated the concentrations of TNFalpha and macrophages in peritoneal fluid of infertile women with minimal or mild endometriosis and related them to the presence of peritoneal red lesions alone (red lesions only group; n = 11) or their absence (non-red lesions group; n = 36). A group of 39 infertile normo-ovulatory patients with normal pelvic anatomy was used as controls. TNFalpha concentrations did not differ between controls and either group of patients. Patients with red lesions only had significantly lower concentrations of TNFalpha in peritoneal fluid (P < 0.05) and had a higher proportion of samples with undetectable concentrations (P < 0.05) than patients without red lesions. The significant difference in TNFalpha concentrations was present when comparing the groups of patients in the proliferative phase but not in the secretory phase. Macrophage concentrations were not different in the groups. Our findings are compatible with an impairment of macrophage function and therefore lend support to the theory that an inappropriate immunological response of the peritoneal environment to regurgitated endometrium may play a part in the initial phases of endometriotic implants.     

Women with endometriosis have increased levels of placental growth factor in the peritoneal fluid compared with women with cystadenomas

BACKGROUND: To assess the release of placental growth factor (PlGF) into peritoneal fluid in women with and without endometriosis, we measured its concentration with reference to disease stage, the presence of red endometriotic lesions and the phase of menstrual cycle. METHODS: Surgery was scheduled in the proliferative or secretory phase of the menstrual cycle for 59 women with (n = 35) or without (n = 24) endometriosis. The latter group comprised women undergoing surgery for ovarian cystadenomas. PlGF concentrations in the peritoneal fluid were measured using an enzyme-linked immunosorbent assay. RESULTS: PlGF concentration in the peritoneal fluid was markedly elevated in the endometriosis patients (median 189 pg/ml, interquartile range 84-475 pg/ml) as compared with the controls (88 pg/ml, 41-213 pg/ml; P < 0.001), especially in women with red lesions. Significantly greater values during the secretory phase of the menstrual cycle as compared with the proliferative phase were observed in both the control (cystadenoma) group (P < 0.05) and the endometriosis group (P < 0.001). CONCLUSIONS: Our findings suggest that production of PlGF is sensitive to the cyclic changes in ovarian steroids and may contribute to the pathogenesis of endometriosis, especially that of red lesions, by promoting neovascularization.     

Increased levels of interleukin-15 in the peritoneal fluid of women with endometriosis: inverse correlation with stage and depth of invasion

BACKGROUND: Interleukin (IL)-15 is a novel cytokine with immunoregulatory and angiogenic properties. We compared IL-15 levels in the peritoneal fluid (PF) of women with and without endometriosis. METHODS: PF samples were obtained from 55 women with endometriosis (23 with superficial peritoneal implants, 19 with deep endometriotic implants and 13 with ovarian endometriomas). Eighteen women with normal pelvic anatomy undergoing tubal sterilization served as controls. RESULTS: PF IL-15 concentrations were increased in women with endometriosis (2.7 +/- 0.5 pg/ml) versus controls (2.1 +/- 0.3 pg/ml; P < 0.001). However, IL-15 levels were higher in women with superficial peritoneal implants (2.9 +/- 0.5 pg/ml) than women with deep endometriotic implants (2.6 +/- 0.4 pg/ml; P = 0.01) or ovarian endometriomas (2.2 +/- 0.4 pg/ml; P < 0.001). IL-15 was also higher in women with deep implants than in those with endometriomas (P < 0.05). PF IL-15 correlated inversely with both depth of invasion (r = -0.52) and the stage of endometriosis (r = -0.42). PF IL-15 levels demonstrated little variation during the menstrual cycle, and did not discriminate between women with infertility or pelvic pain. CONCLUSION: PF IL-15 levels are increased in women with endometriosis. However, IL-15 levels are inversely correlated with the depth of invasion and disease stage, suggesting a possible role for this cytokine in the early pathogenesis of endometriosis.     

Spindle cell ductal carcinoma in situ. An unusual variant of ductal intra-epithelial neoplasia that simulates ductal hyperplasia or a myoepithelial proliferation

It is well known that the number of peritoneal macrophages is increased in patients with pelvic endometriosis. We measured the concentration of monocyte chemoattractant protein-1 (MCP-1) using an enzyme-linked immunosorbent assay (ELISA) in the peritoneal fluid of women with and without endometriosis. The expression of MCP-1 in pelvic endometriotic lesions obtained from the peritoneum was also examined using immunohistochemistry and nonradioactive in situ hybridization. The mean concentration of MCP-1 in the peritoneal fluid was significantly higher in the patients with endometriosis (P<0.05). The most significant elevation, compared with non-endometriosis patients, was found in stage I of the disease (P<0.05). However, no statistically significant difference was found among endometriosis stages I, II, III, and IV. Immunohistochemical staining revealed that MCP-1-positive cells were localized in the glandular epithelium of the endometriotic lesions and in the stromal macrophages distributed in those lesions, but normal peritoneal cells were negative. The in situ hybridization method demonstrated expression of MCP-1 mRNA on the endometriotic glandular epithelium and stromal macrophages. These findings suggest that MCP-1 may be involved in the histogenesis and early development of peritoneal endometriosis.     

Hyperalgesia,nerve infiltration and nerve growth factor expression in deep adenomyotic nodules,peritoneal and ovarian endometriosis

BACKGROUND: The aim of this study was to investigate a possible role for nerve growth factor (NGF) in the mechanism of pain and hyperalgesia induced by deep adenomyotic nodules and other forms of endometriosis and to clarify the relationship between endometriotic lesions and the surrounding nerves. METHODS: Endometriotic lesions (deep adenomyotic nodules, peritoneal endometriosis, ovarian endometriosis) and eutopic endometrium were obtained from 51 patients presenting with pain. Patients were allocated to two groups (group 1: patients with a deep adenomyotic nodule (n = 23); group 2: patients with peritoneal and/or ovarian endometriosis but without deep adenomyotic nodule (n = 28). Immunohistochemistry with antibodies against NGF, NGF specific tyrosine-kinase receptor (Trk-A) and S-100 protein was performed. Results were expressed as mean H-scores +/- SD, and correlated with the presence of hyperalgesia. RESULTS: The percentage of patients presenting hyperalgesia at physical examination was significantly higher in group 1 (96%) than in group 2 (11%) (P < 0.001). NGF expression was significantly stronger in deep adenomyotic nodules (DAN) than in ovarian (OE) and peritoneal endometriosis (PE), both in the proliferative phase in the glands [DAN: 226 +/- 18; OE: 140 +/- 9 (P < 0.001); PE: 110 +/- 7 (P < 0.001)] and in the stroma [(DAN: 204 +/- 21; OE: 125 +/- 15 (P < 0.001); PE: 100 +/- 9 (P < 0.01)]. NGF expression in DAN is also significantly stronger than in OE and PE in the secretory phase in the glands [DAN:181 +/- 32; OE: 85 +/- 3.3 (P < 0.001); PE: 65 +/- 9 (P < 0.001)] and in the stroma [DAN: 173 +/- 28; OE: 85 +/- 3.7 (P < 0.001); PE: 35 +/- 13 (P < 0.001)]. Perineurial and intraneurial invasion by endometriotic lesions were found only in deep adenomyotic nodules and not in the other forms of endometriosis. The specific receptor for NGF (Trk-A) is expressed in all the nerves that were included in the biopsies. CONCLUSIONS: These results suggest a role of NGF in endometriotic pain and hyperalgesia in deep adenomyotic nodules. The strong expression of the NGF-TrkA pathway in deep adenomyotic nodules could explain why this type of lesion infiltrates in richly innervated anatomical sites.     

Critical role for iron accumulation in the pathogenesis of fibrotic lung disease

Increased iron levels and dysregulated iron homeostasis, or both, occur in several lung diseases. Here, the effects of iron accumulation on the pathogenesis of pulmonary fibrosis and associated lung function decline was investigated using a combination of murine models of iron overload and bleomycin-induced pulmonary fibrosis, primary human lung fibroblasts treated with iron, and histological samples from patients with or without idiopathic pulmonary fibrosis (IPF). Iron levels are significantly increased in iron overloaded transferrin receptor 2 (Tfr2) mutant mice and homeostatic iron regulator (Hfe) gene–deficient mice and this is associated with increases in airway fibrosis and reduced lung function. Furthermore, fibrosis and lung function decline are associated with pulmonary iron accumulation in bleomycin-induced pulmonary fibrosis. In addition, we show that iron accumulation is increased in lung sections from patients with IPF and that human lung fibroblasts show greater proliferation and cytokine and extracellular matrix responses when exposed to increased iron levels. Significantly, we show that intranasal treatment with the iron chelator, deferoxamine (DFO), from the time when pulmonary iron levels accumulate, prevents airway fibrosis and decline in lung function in experimental pulmonary fibrosis. Pulmonary fibrosis is associated with an increase in Tfr1⁺ macrophages that display altered phenotype in disease, and DFO treatment modified the abundance of these cells. These experimental and clinical data demonstrate that increased accumulation of pulmonary iron plays a key role in the pathogenesis of pulmonary fibrosis and lung function decline. Furthermore, these data highlight the potential for the therapeutic targeting of increased pulmonary iron in the treatment of fibrotic lung diseases such as IPF. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Distinct mechanisms regulate cyclooxygenase-1 and -2 in peritoneal macrophages of women with and without endometriosis

Prostaglandin (PG) E2 has been shown to stimulate steroidogenesis in ectopic endometriotic stromal cells and may be involved in the development of endometriosis since this disorder is highly estrogen dependent. The biosynthesis of PGE2 is controlled by the rate-limiting enzyme termed cyclooxygenase (COX). The objective of the current study was to investigate the expression of COX in peritoneal macrophages isolated from women with and without endometriosis, and to explore the effects of pro-inflammatory agents on COX expression in peritoneal macrophages. Using quantitative RT-PCR and Western blot analyses, we found that expression of COX-2 was markedly increased (P < 0.05) in peritoneal macrophages isolated from women with early or severe endometriosis, whereas expression of COX-1 was elevated only in the severe stage (P < 0.05). On the contrary, monocytes/macrophages purified from peripheral blood of patients with endometriosis had minimal or undetectable levels of COX-2, and this was not different from disease-free women. Treatment with interleukin-1beta, tumour necrosis factor-alpha or PGE2 caused a significant increase in COX-2 (P < 0.05) but not COX-1 expression in peritoneal macrophages isolated from disease-free women. In contrast, these agents had no substantial effect on COX-1 and COX-2 expression in peritoneal macrophages from women with endometriosis. In summary, expression of COX in peritoneal macrophages was associated with the severity of endometriosis. Elevated expression of both COX-1 and COX-2 in peritoneal macrophages may contribute to the increased peritoneal fluid PGE2 concentrations and may thus play an important role in the development of endometriosis.     

Comparing qualitative and quantitative spectroscopic techniques for the detection of the effect of direct iron loading of mammalian cell cultures

Iron overload augments diseases of the liver and microorganism infection as well as deregulates the immune system. In vitro analysis of the effects of iron loading and its chelation involves determining the amount of iron constituting overload, which metal sources and cell lines to use and reliable assay methods. The uptake of 500 µM FeSO₄ or FeEDTA by CEMss, U937 or leukocytes was confirmed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Excess iron increased CEMss viability (assessed by MTT, XTT, Trypan-and Alamar Blue) by an average of 18% (P = 0.034). Flow cytometry indicated dye-viable cells to be undergoing apotosis/necrosis while still confirming an increase (9%, P < 0.001) in excess iron-induced viability. The iron chelator desferioxamine (DFO) when added in addition to Fe, reversed the effects of excess iron (and vice versa) and had detrimental effects when used on its own (33% inhibition of viability as measured by dyes and 10.85%; P = 0.0427 assessed by flow cytometry). The 4 dyes demonstrated different levels of sensitivity in detecting the influence of iron or DFO but gave a related, qualitative picture while flow cytometry and ICP-AES data was more quantitative.     

Nerve fibres in peritoneal endometriosis

BACKGROUND: Endometriosis is a gynaecological disease that can be associated with severe pelvic pain; however, the mechanisms by which pain is generated remain unknown. METHODS: Peritoneal endometriotic lesions and normal peritoneum were prepared from women with and without endometriosis (n = 40 and 36, respectively). Specimens were also prepared from endosalpingiosis lesions (n = 9). These sections were stained immunohistochemically with antibodies against protein gene product 9.5, neurofilament (NF), nerve growth factor (NGF), NGF receptor p75 (NGFRp75), substance P (SP), calcitonin gene-related peptide (CGRP), acetylcholine (ACh) and tyrosine hydroxylase (TH) to demonstrate myelinated, unmyelinated, sensory, cholinergic and adrenergic nerve fibres. RESULTS: There were significantly more nerve fibres identified in peritoneal endometriotic lesions than in normal peritoneum (P < 0.001) or endosalpingiosis lesions (P < 0.001). These nerve fibres were SP, CGRP, ACh or TH immunoreactive. Many of these markers were co-localized. There was an intense NGF immunoreactivity near endometriotic glands, and NGFRp75 immunoreactive nerve fibres were present near endometriotic glands and blood vessels in the peritoneal endometriotic lesions. CONCLUSIONS: Peritoneal endometriotic lesions were innervated by sensory Adelta, sensory C, cholinergic and adrenergic nerve fibres. These nerve fibres may play an important role in the mechanisms of pain generation in this condition.     

IL-1, IL-6 and TNF-alpha concentrations in the peritoneal fluid of women with pelvic adhesions.

BACKGROUND: Pelvic adhesions are a significant cause of morbidity and are associated with infertility and pain. The three pro-inflammatory cytokines interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-alpha are involved in adhesion formation/reformation. METHODS: The concentration of these three cytokines was examined in the peritoneal fluid of women undergoing laparoscopy, in order to examine the factors affecting their concentrations, with specific reference to the presence or absence of adhesions. RESULTS: We found that the concentration of TNF-alpha in the peritoneal fluid was significantly correlated to the menstrual cycle day (P < 0.01), with increasing concentration as the menstrual cycle progressed from the follicular to the luteal phase. In contrast, IL-1 and IL-6 levels did not show any variation throughout the menstrual cycle. Increased TNF-alpha was found in patients with pelvic adhesions compared with those with normal pelvis; the concentration of TNF-alpha was highest in mild compared with severe adhesions. In contrast, IL-1 concentration was higher in the presence of severe adhesions. IL-6 levels were significantly correlated with the grade of endometriosis (P < 0.05), but there were no significant correlations of either TNF-alpha or IL-1 concentrations with the various grades of endometriosis. CONCLUSION: The exact role of TNF-alpha and IL-1 in adhesion formation is still unknown, but the results from this study suggest that their concentration in the peritoneal fluid is associated with the degree of adhesions present.     

Peritoneal fluid leptin is associated with chronic pelvic pain but not infertility in endometriosis patients

BACKGROUND: Leptin influences the proinflammatory immune responses and has angiogenic activity in vitro and in vivo. The objective of this study was to evaluate the peritoneal fluid levels of leptin in patients with endometriosis and idiopathic infertility and compare them with a control group of tubal ligation/reanastomosis patients. METHODS: In this observational, prospective controlled study, peritoneal fluid from 108 women was obtained while they underwent laparoscopy for pelvic pain, infertility, tubal ligation or sterilization reversal. We measured the concentration of leptin in the peritoneal fluid and compared the levels among women who were divided into groups according to their post-surgical diagnosis. Sixty patients were diagnosed with endometriosis, 10 with idiopathic infertility and 38 had undergone tubal ligation or reanastomosis (control group). RESULTS: Peritoneal fluid leptin was significantly higher in endometriosis 14.62+/-9.79 (mean+/-SD) ng/ml compared to idiopathic infertility [0.92+/-1.57 ng/ml (P=0.0007)] and to controls [0.78+/-1.94 ng/ml (P<0.0001)]. Leptin levels were positively correlated with the stage of endometriosis (r=0.45; P=0.03), and with pelvic pain in endometriosis patients (r=0.49; P=0.001). Peritoneal fluid leptin levels in patients with idiopathic infertility were comparable to controls. CONCLUSIONS: Higher levels of leptin were observed in peritoneal fluid of patients with endometriosis compared to those without the disease. These data suggest that the proinflammatory and neoangiogenic action of leptin may contribute to the pathogenesis of endometriosis. Moreover, leptin may play a role in endometriosis-associated pain.     

Differential expression and localization of de-novo synthesized endometriotic haptoglobin in endometrium and endometriotic lesions

Endometriosis protein-I (ENDO-I) mRNA expression and protein localization were evaluated using in-situ hybridization and immunohistochemistry in endometriotic lesions and eutopic endometrium from women with endometriosis, and in eutopic endometrium from women without endometriosis (controls). When present, ENDO-I mRNA and protein were observed in the functionalis zone of endometrial stroma and the stroma of endometriotic lesions. Expression and localization differences were scored and statistically analysed. During the secretory stage, ENDO-I mRNA expression by endometriotic lesions and eutopic endometrium from women with disease was significantly greater than ENDO-I mRNA expression by proliferative stage eutopic endometrium from women with disease or eutopic endometrium from controls, regardless of cycle stage (P < 0.001). More ENDO-I protein was localized in endometriotic lesions and eutopic endometrium from women with disease than in eutopic endometrium from controls, regardless of cycle stage (P < 0.001). Differential expression and localization of ENDO-I may help develop minimally invasive diagnostic strategies for endometriosis. Further, as ENDO-I shares nucleotide sequence and amino acid sequence with hepatic haptoglobin-which in certain disease states is immunosuppressive and angiogenic-differences in ENDO-I expression and localization in the peritoneal cavity may contribute to the pathogenesis of endometriosis and/or facilitate development of unprecedented diagnostic or therapeutic approaches for management of this enigmatic disease.     

Possible implication of midkine in the development of endometriosis

BACKGROUND: The present study was conducted to assess whether midkine (MK), a multifunctional molecule known to stimulate tumor growth, may be involved in the development of endometriosis. METHODS: The mitogenic activity of MK on cultured endometriotic stromal cells was examined by measuring 5-bromo-2'-deoxyuridine (BrdU) incorporation. Concentrations of MK in the peritoneal fluid (PF) of women without or with endometriosis and those under GnRH agonist treatment were measured using a specific enzyme immunoassay. The expression of MK mRNA in peritoneal bone marrow-derived cells, peritoneum and endometriotic tissues was evaluated by RT-PCR. RESULTS: MK significantly increased BrdU incorporation into the DNA of cultured endometriotic stromal cells. The MK concentrations in the PF of the women with advanced endometriosis (stages II, III and IV) Median: 1.21 ng/ml; interquartile range 0.80-2.27 were significantly higher than those of the women without endometriosis and with stage I endometriosis (0.06 ng/ml, 0.67-1.26, P < 0.05). As for the menstrual phase, the MK concentration in PF in the inteal phase (1.32 ng/ml. 0.72-2.21) were significantly higher than those in the follicular phase (0.95 ng/ml, 0.68-1.24, P < 0.05). In addition, women with adnexal adhesions had higher concentrations of MK in PF than those without adhesions (P < 0.05). The MK concentrations of the women under GnRH agonist treatment were significantly lower than those of the other groups (P < 0.001). The expression of MK mRNA was detected in peritoneal bone marrow-derived cells, peritoneum and endometriotic tissues. CONCLUSIONS: The present findings suggest that MK may play roles, such as stimulation of endometriotic cell proliferation, in the development of endometriosis.     

Inverse correlation between peritoneal fluid leptin concentrations and the extent of endometriosis

BACKGROUND: The role of leptin in reproductive processes has received increasing attention. Because leptin has intrinsic angiogenic properties, may be induced by inflammatory cytokines and induces matrix metalloproteinases, we examined peritoneal fluid (PF) leptin concentrations in women with endometriosis. METHODS: PF samples were collected from 60 women undergoing laparoscopy for endometriosis, and 18 controls undergoing tubal sterilization. Fifty of the women with endometriosis had received no prior hormonal treatment, while 10 with moderate- severe endometriosis were using GnRH agonists. RESULTS: Women with untreated endometriosis had significantly higher (mean +/- SD) PF leptin levels (34.9 +/- 7.9 ng/ml) than controls (17.9 +/- 4.1 ng/ml; P < 0.001). However, PF leptin levels were inversely correlated with the stage of disease (r = -0.62; P < 0.001). Nevertheless, women with stage III-IV endometriosis maintained significantly higher PF leptin levels (26.3 +/- 4.8 ng/ml; P < 0.001) than controls. Although PF leptin levels were significantly higher in the secretory versus proliferative phase of the menstrual cycle, they remained higher in both phases in women with untreated endometriosis. PF leptin levels in women on GnRH agonists were similar to controls. CONCLUSIONS: PF leptin levels are elevated in women with endometriosis, but inversely correlated with extent of disease. These findings suggest a potential role for leptin in the pathogenesis of peritoneal endometriosis.     

The role of monocyte chemotactic protein-1 in intraperitoneal adhesion formation

Abdomino-pelvic adhesions arise from infection, endometriosis, or peritoneal injury during surgery, and represent a significant source of morbidity in women of reproductive age. Monocyte chemotactic protein-1 (MCP-1) plays a role in the chemotaxis of mononuclear cells and fibroblasts in a murine wound repair model. To evaluate the role of MCP- 1 in intraperitoneal adhesion formation, we investigated peritoneal fluid MCP-1 levels of women undergoing laparoscopy. Patients without endometriosis were divided into two groups: normal fertile women undergoing bilateral tubal ligation without intraperitoneal adhesions (n=14) and women with pelvic adhesions (n=8). Patients with endometriosis were arranged into two groups: women with (n=17) and without (n=17) adhesions. Peritoneal fluid MCP-1 levels were quantified using an enzyme-linked immunosorbent assay (ELISA). Peritoneal biopsy samples were immunostained for the detection of MCP-1 protein and macrophages, and were also processed for the presence of MCP-1 mRNA expression. Among women without endometriosis, the median peritoneal fluid MCP-1 level was 144 pg/ml (range 54-261) in women without adhesions and was 336 pg/ml (range 130-2494) in women with adhesions (P=0.01). There was a significant correlation between adhesion scores and MCP-1 levels (r=0.50; P=0.018). Among women with endometriosis, peritoneal fluid MCP-1 levels significantly correlated with the stage of the disease. The presence or absence of adhesions did not significantly affect the peritoneal fluid MCP-1 levels in this group of women. In summary, we have found that women with adhesions have elevated peritoneal fluid MCP-1 levels. However, we were not able to show an incremental effect of adhesions on peritoneal fluid MCP-1 levels of patients with endometriosis. Thus, we conclude that factors besides the intraperitoneal adhesions contribute to the elevated peritoneal fluid MCP-1 levels in patients with endometriosis.      

Expression of interleukin-8 receptors in endometriosis

BACKGROUND: Although the etiology of endometriosis is not well understood, chemokines and their receptors are believed to play a role in its pathogenesis. Therefore, we aimed to investigate the expression and localization of interleukin-8 (IL-8) receptors CXCR1 and CXCR2 in eutopic and ectopic endometrial tissues of women with endometriosis, and in endometrium of women without endometriosis. METHODS: Ectopic (n = 27) and homologous eutopic endometrium (n = 25) from women with endometriosis and endometrium from women without endometriosis (n = 27) were used for immunohistochemical analysis of CXCR1 and CXCR2. RESULTS: In normal endometrium, epithelial CXCR1 and CXCR2 immunostaining intensities were similar in the proliferative and secretory phase. Stromal CXCR1 expression was less then epithelial expression and did not show cyclical difference. No stromal CXCR2 expression was observed. In eutopic endometrium of women with endometriosis compared to endometrium of women without endometriosis, there was a significant increase in both proliferative and secretory phases for epithelial CXCR2 expression, and in proliferative phase for CXCR1 expression (P < 0.05). Both receptor immunoreactivities were significantly increased in the epithelial cells of ectopic endometrial tissues compared to that of normal endometrium (P < 0.05). CONCLUSIONS: These findings suggest that IL-8 and its receptors may be involved in the pathogenesis of endometriosis.     

Peritoneal fluid concentrations of interleukin-8 in patients with endometriosis depend on the severity of the disorder and are higher in the luteal phase

BACKGROUND: Previous evaluations of the relationship between the concentrations of interleukin-8 (IL-8) in the peritoneal fluid and endometriosis led to non-consistent results. Our purpose was to investigate the correlation of the concentrations of IL-8 in the peritoneal fluid with the stage of endometriosis, the presence of red lesions and the phase of the menstrual cycle. METHODS: Ninety-two patients with infertility (n = 87) or undergoing sterilization (n = 5) had peritoneal fluid samples collected at laparoscopy. IL-8 determinations were performed using an enzyme-linked immunosorbent assay. RESULTS: The concentrations of IL-8 in the peritoneal fluid of the 68 women with endometriosis were not significantly different from those of the 24 controls. Patients with moderate/severe stages had IL-8 significantly higher than controls (P = 0.008) and marginally higher than patients with minimal/mild endometriosis (P = 0.053). Concentrations of IL-8 were significantly higher in patients than in controls in the luteal phase. Red lesions were associated with significantly increased levels of peritoneal fluid IL-8 only in the luteal phase. CONCLUSIONS: Our findings reinforce the importance of IL-8 in the pathogenesis of endometriosis.