Cytokine regulation of cellular proliferation in endometriosis

Transcriptomic changes in eutopic endometrium and ectopic lesions during endometriosis progression in a mouse model

OBJECTIVE

To identify the transcriptomic changes of ectopic lesions and eutopic endometrial tissues during the progression of endometriosis, we performed transcriptomic analysis in the eutopic endometrium and ectopic lesions.

DESIGN

Laboratory study.

SETTING

Academic medical center.

ANIMALS

Four fertile and 4 subfertile Pgrcre/+Rosa26mTmG/+ mice with endometriosis, and 4 sham mice for each group of endometriosis mice as control. These mice underwent either surgery to induce endometriosis or sham surgery. Fertile sham and mice with endometriosis were used 1 month after surgery, whereas subfertile ones were used 3 months after surgery.

INTERVENTIONS

Early and chronic effects of endometriosis on transcriptomics of ectopic lesions and eutopic endometrium.

MAIN OUTCOME MEASURES

RNA-sequencing analysis and identification of differentially expressed genes and pathways in the ectopic lesions and eutopic uteri from mice with endometriosis and sham mice at day 3.5 of pregnancy.

RESULTS

Our mouse model recapitulates the transcriptomic changes of ectopic lesions in humans. RNA-sequencing analysis was performed in ectopic lesions and eutopic uteri from mice with or without endometriosis during the progression of the disease. Estrogen activity, inflammation, angiogenesis, and fibrosis pathways were consistently elevated in all the ectopic lesions compared with eutopic endometrium. Cholesterol/glucose synthesis and stem cell pluripotency pathways were more enhanced in ectopic lesions from subfertile mice compared with their eutopic endometrium. Dysregulation of infiltration of macrophage, dendritic, T and B cells was validated with the use of immunohistochemistry in ectopic lesions. Multiple ligand-receptor pairs between the ectopic and eutopic endometrium were altered compared with the sham endometrium. Suppressed WNT and EGF pathways were only found in the eutopic endometrium from subfertile not fertile mice compared with sham.

CONCLUSIONS

Our mouse endometriosis model recapitulates the transcriptomics of ectopic lesions in humans. Our transcriptomic analysis during endometriosis progression in our mouse model will help us understand the pathophysiology of endometriosis.

Extensive heterogeneity in the expression of steroid receptors in superficial peritoneal endometriotic lesions

RESEARCH QUESTION

Is the expression of steroid hormone receptors (oestrogen receptor-α and progesterone receptor A/B) and proliferative markers (Bcl-2 and Ki67) uniform among superficial peritoneal endometriotic lesions?

DESIGN

A retrospective cohort study of 24 patients with surgically and histologically confirmed endometriosis. Immunofluorescence was used to determine the proportion of oestrogen receptor-α (ERα), progesterone receptor A/B, Bcl-2 and Ki67 positive cells in 271 endometriotic lesions (defined as endometriotic gland profile/s within an individual region of CD10 stromal immunostaining from a single biopsy) from 67 endometriotic biopsies from 24 patients. Data were analysed to examine associations related to menstrual cycle stage, lesion location and gland morphology.

RESULTS

Oestrogen receptor-α and progesterone receptor A/B expression in superficial peritoneal endometriotic lesions was extremely heterogeneous. Bcl-2 immunostaining in endometriotic lesions was also variable, whereas Ki67 immunostaining was minimal. Menstrual cycle stage associations were limited in steroid hormone receptor and Bcl-2 expression in lesions. Patterns in progesterone receptor A/B and Bcl-2 immunostaining were associated with lesion location. Bcl-2 was differentially expressed, based on lesion gland morphology.

CONCLUSIONS

These data demonstrate considerable diversity in the expression of steroid hormone receptors and Bcl-2 between lesions, even within an individual patient.

Decreased Level of Neurotrophic Factor Neuritin 1 in Women with Ovarian Endometriosis after Receiving Gonadotropin-Releasing Hormone Agonist Treatment

This study aimed to investigate the effect of gonadotropin-releasing hormone agonist (GnRHa) treatment on the expression of neuritin 1 (NRN1) in women with ovarian endometriosis. We collected tissues and serum from women with endometriosis treated with (n = 45) or without (n = 37) GnRHa. NRN1 mRNA and protein levels were measured using qPCR and Western blot. Immunolocalization of NRN1 in endometriotic tissues was examined using immunohistochemistry. In addition, a follow-up study was carried out to monitor the serum level of NRN1 in patients before and after GnRHa treatment. Both mRNA (p = 0.046) and protein (p = 0.0155) levels of NRN1 were significantly lower in endometriotic tissues from patients receiving GnRHa treatment compared to the untreated group. Both epithelial and stromal cells of endometriotic tissues from untreated women with endometriosis exhibited stronger staining of NRN1 but not in those who were treated with GnRHa. The follow-up study showed that the serum level of the NRN1 concentration decreased significantly from 1149 ± 192.3 to 379.2 ± 80.16 pg/mL after GnRHa treatment (p = 0.0098). The expression of NRN1 was significantly lower in women with ovarian endometriosis treated with GnRHa. These results suggest that NRN1 may be a biomarker response to the effect of GnRHa treatment for patients with ovarian endometriosis.

Promising activity of Anthemis austriaca Jacq. on the endometriosis rat model and isolation of its active constituents

Anthemis austriaca Jacq. flowers are traditionally used to alleviate abdominal pain, hemorrhoids, ovary diseases and pneumonia. This study aimed to investigate the effects of A. austriaca flowers, which are frequently used in gynecological disorders, on the rat endometriosis model. The rat endometriosis model was used to evaluate the potential activity of the plant in endometriosis. The dried plant material was extracted with n-hexane, ethyl acetate (EtOAc), and methanol (MeOH), successively. The obtained extracts from A. austriaca flowers were applied to the rats. The adhesion scores, endometrial foci areas, and cytokine levels of the peritoneal fluids were measured on surgical induction of endometriosis in rats. The adhesion scores, endometriotic volume, and cytokine levels of the peritoneal fluids were reduced in the EtOAc, MeOH, and buserelin acetate-treated (reference) groups. The MeOH extract reduced the adhesion scores and endometrial foci areas from 3.1 to 1.1 (p < 0.01) and from 86.4 to 40.5 (p < 0.01), respectively and also the MeOH extract reduced tumor necrosis factor (TNF)-α, vascular endothelial growth factor (VEGF), and interleukin (IL)-6 levels of the peritoneal fluids from 13.7 to 3.8 (p < 0.01), from 28.4 to 16.3 (p < 0.05) and from 50.2 to 24.3 (p < 0.01), respectively. Therefore, isolation studies were conducted on the EtOAc and MeOH extracts. After the MeOH extract was fractionated using RP-18 column, the obtained subfractions were evaluated again on the endometriosis rat model. Subfractions A and C of the MeOH extract displayed statistically significant activity on the endometriosis rat model. Phytochemical investigation resulted in the isolation of 4-β-D-glucopyranosyloxy-6-methyl-2H-pyran-2-one (1) from Fr. A and quercetin (2), apigenin-7-O-(3″-O-acetyl)-β-D-glucopyranoside (3), apigenin-7-O-(6″-O-acetyl)-β-D-glucopyranoside (4), apigenin-7-O-β-D-glucopyranoside (5), quercetin-7-O-β-D-glucopyranoside (6) from Fr. C. Moreover, β-sitosterol-3-O-β-D-glucopyranoside (7) was isolated from the EtOAc extract. As a conclusion, the MeOH extract obtained from A. austriaca flowers contributed to the regression of endometriosis. In addition, flavonoids and sterols of the plant were detected as the possible compounds responsible for the activity.

Premature Immunosenescence Impairs Immune Surveillance Allowing the Endometriotic Stem Cell to Migrate: The Cytokine Profile as a Common Denominator

While endometriosis, one of the most common reasons for infertility, remains a multifactorial condition and its exact cause highly speculative, there are data pointing to novel pathways of disease initiation which involve a stem cell and its ability to migrate and implant after it differentiates into an endometriotic stem cell. Thus, the mechanisms conferring immune surveillance, which would also normally expel the mesenchymal endometriotic cell, impairing its migration and implantation, appear to be negatively influenced by a state of endometriotic premature immunosenescence. This interplay between the two immunological mechanisms and endometriosis is influenced by a number of common factors having an active role in the host's protection process that inhibits harmful diseases and maintains cellular homeostasis. It appears more than coincidental that production/inhibition of IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-15, IL-18, TNF-α, VEGF, ICAM-1, and the number of Tolllike receptors is the same in immunosenescent states and in conditions with reduced immune surveillance, while the same variations are recorded in endometriotic patients. It is probable that these are common to all process signals, guide the endometriotic stem cell and dictate its fate according to the stochastic, transdifferentiation (plasticity) or deterministic model to become capable of migration and tissue invasion. It is currently unknown whether the pathway taken by the hemopoietic stem cell to become endometriotic represents a normal or aberrant route of development. This prompts research into its isolation and in vitro study of its behavior in order to reveal its potential function and role in endometriosis. (Journal of Endometriosis 2010; 2: 7–18)

Association of peroxisome proliferator-activated receptor-gamma 2 Pro12Ala polymorphism with advanced-stage endometriosis

PROBLEM

To investigate whether the peroxisome proliferator-activated receptor (PPAR)-γ2 Pro12Ala polymorphism is associated with a risk of advanced-stage endometriosis in a Korean population.

METHODS OF STUDY

  Case-control study in a collective of 446 patients and 427 controls. The Pro12Ala polymorphism of PPAR-γ2 gene was genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis.

RESULTS

The distribution of the PPAR-γ2 Pro12Ala polymorphism was different between the advanced-stage endometriosis group and the control group (non-CC rates were 5.2% for patients with advanced endometriosis and 10.1% for the control group, respectively, P = 0.006). The frequency for the Ala-12 allele variant was significantly lower in patients with advanced stage of endometriosis (2.7%) than in the control group (5.3%) (P = 0.006).

CONCLUSION

These findings suggest that the PPAR-γ2 Pro12Ala polymorphism is associated with advanced-stage endometriosis in the Korean population. Unlike results from other studies reported so far, the Ala-12 allele may have protective effects against advanced-stage endometriosis in the Korean population.

Interleukin-1 stimulates macrophage migration inhibitory factor secretion in ectopic endometrial cells of women with endometriosis

PROBLEM

Macrophage migration inhibitory factor (MIF), a potent immuno-modulatory, angiogenic and tissue remodeling factor, is markedly expressed in ectopic endometrial implants and may play key role in the capability of this tissue to grow and develop into the host tissue. The objective of this study was to determine whether macrophage-derived cytokines, such as interleukin (IL)-1, which is overproduced by endometriosis women's peritoneal macrophages and found in elevated concentration in their peritoneal fluid, may play a role in MIF synthesis and secretion by ectopic endometrial cells.

METHODS OF STUDY

Primary cultures of endometriotic cells exposed to IL-1beta and evaluation of MIF protein by immunocytofluorescence and ELISA, and mRNA by quantitative real-time PCR and nuclear transcription assays (run-on).

RESULTS

Interleukin-1beta acts rapidly on endometriotic cells and stimulated MIF secretion and mRNA steady-state levels in a dose and time-dependent manner. IL-1beta treatment had no significant effect on MIF mRNA half-life and stability, but acted predominantly by up-regulating MIF gene transcription as assessed by run-on.

CONCLUSION

These data clearly indicate that IL-1 can be involved in the up-regulation of MIF expression by ectopic endometrial implants. Such an interaction between IL-1 and MIF may have an important impact on endometriotic cell growth and endometriosis pathophysiology.

Effect of peroxisome proliferator-activated receptor-gamma agonist rosiglitazone on the induction of endometriosis in an experimental rat model

OBJECTIVE

To assess the effect of the peroxisome proliferator-activated receptor (PPAR)-gamma agonist rosiglitazone on the induction of endometriosis in a rat model.

METHODS

Endometriosis was surgically induced in 28 rats by transplanting an autologous fragment of endometrial tissue onto the inner surface of the abdominal wall. Group I was assigned as control and no medication was administered. Starting 3 days before the operation and continuing for 4 weeks, 0.2 mg/kg/d rosiglitazone was administered to the study group orally. Four weeks later rats were killed and ectopic uterine tissues were evaluated morphologically and histologically. Scoring systems were used to evaluate preservation of epithelia.

RESULTS

Four rats in the study group and one rat in the control group died of complications related to surgery. There was a significant difference in post-treatment spherical volumes (64.00 mm3 [interquartile range (IQR): 354.42] vs 41.60 mm3 [IQR: 37.87], P = .018) and explant weights (77.97 mg [IQR: 431.27] vs 47.24 mg [IQR: 43.01], P = .005) between control and rosiglitazone-treated groups. The epithelia were found to be preserved significantly better in the control group when compared with the roziglitazone-treated group (2.00 [IQR:2.00] vs 0.00 [IQR:2.25], P = .014).

CONCLUSIONS

Rosiglitazone was found to affect the induction of endometriosis negatively in this experimental rat model and seemed to interfere with the growth and maintenance of the uterine explant.

Experimental Intestinal Endometriosis Is Characterized by Increased Levels of Soluble TNFRSF1B and Downregulation of Tnfrsf1a and Tnfrsf1b Gene Expression1

Endometriosis is commonly associated with symptoms similar to those of gastrointestinal diseases, such as inflammatory bowel disease (IBD), leading to erroneous diagnosis and inappropriate management. The role of tumor necrosis factor alpha (TNF) in IBD is well established, but its role in endometriosis--also characterized by the activation of inflammatory mechanisms--is still under study. Furthermore, little is known about the involvement of TNF receptors. Intestinal endometriosis was surgically induced in female Sprague-Dawley rats (n = 10). Control rats (n = 10) received sutures with no implants. Samples of tissue and fluids were collected 60 days after surgery. Endometriotic implants were classified in grades, and the gastrointestinal tract was examined for damage. A significant increase was observed in protein levels of TNF and soluble TNFRSF1B in the peritoneal fluid of experimental rats compared to controls. Expression of Tnf mRNA was significantly increased both in peritoneal leukocytes and in intestinal segments associated with implants in experimental animals. Bioactivity of TNF in tissues was confirmed by overexpression of Icam1, Sele, Vegfa, Flt1 and Kdr. Gene expression of Tnfrsf1a and Tnfrsf1b was downregulated in colon and small intestine of experimental animals, possibly as a mechanism of protection against TNF cytotoxicity. Significant overexpression of genes encoding TNF receptor-associated factors that have been linked to activation of antiapoptotic pathways also was observed. Overexpression of TNF and target genes, underexpression of TNF-receptor genes, and increased shedding of TNFRSF1B in this animal model provide further evidence for involvement of the TNF system in the pathogenesis of endometriosis.

Expression and regulation of CCR1 in peritoneal macrophages from women with and without endometriosis

CCR1 is a CC chemokine receptor with high affinity for RANTES (regulated upon activation, normal T cells expressed and secreted). CCR1 protein and mRNA concentrations in native peritoneal cells were twofold greater, in cultured peritoneal cells threefold greater, in patients with endometriosis compared to patients without endometriosis, as determined by Western blotting fluorescence activated cell sorting analysis, reverse transcription-polymerase chain reaction, and in situ hybridization.

Possible involvement of thrombin/protease-activated receptor 1 system in the pathogenesis of endometriosis

Endometriosis is known to be associated with local inflammatory reactions. Given the emerging concept of thrombin and its specific receptor, protease-activated receptor 1 (PAR1), as important players in inflammation and cell proliferation, we investigated whether thrombin and PAR1 might be involved in the pathophysiology of the disease, using a primary cell culture system of endometriotic tissues. PAR1 mRNA was expressed in primary endometriotic stromal cells (ESCs). Thrombin and SFLLRN (Ser-Phe-Leu-Leu-Arg-Asp), a PAR1 agonist peptide, increased the mRNA expression of IL-8, monocyte chemoattractant protein-1 (MCP-1), and cyclooxygenase-2 (COX-2) and the protein secretion of IL-8 nd MCP-1 in ESCs. The addition of thrombin inhibitor d-phenylalanyl-l-prolyl-l arginine chloromethyl ketone (PPACK) together with thrombin inhibited the thrombin-induced secretion of IL-8 and MCP-1. Thrombin, but not SFLLRN, activated matrix metalloproteinase-2 in ESCs, and the effect was inhibited by PPACK. Thrombin and SFLLRN increased proliferating cell nuclear antigen-positive ratio of ESCs, indicating their cell proliferation-stimulating effects. The thrombin-induced increase in proliferating cell nuclear antigen-positive ratio was diminished by PPACK. These findings imply that the thrombin system might be involved in the pathophysiology of endometriosis, stimulating inflammatory responses of endometriotic cells and their mitogenic activity.

The role of cytokines in endometriosis

PROBLEM

To review the literature on the role of peritoneal cytokines in the pathogenesis and endometriosis-related infertility.

METHODS OF STUDY

A MEDLINE search was conducted by the key words of cytokine and endometriosis in the English publications, and references identified within the identified papers were also reviewed.

RESULTS

Several cytokines including interleukin (IL)-1, 6, 8, 10, tumor necrosis factor (TNF)-alpha, and vascular endothelial growth factor (VEGF) were reported to be increased in the peritoneal fluid (PF) of women with endometriosis. Those cytokines may be involved in macrophage activation, inflammatory change and enhanced angiogenesis. However, some cytokines were less expressed such as IL-2, and interferon (IFN)-gamma. They reflect the impaired T- and natural killer (NK)-cell function. Endometriotic implants produce some factors, e.g. matrix metalloproteinases (MMPs), Bcl-2, and affect their capacity to implant into the peritoneum.

CONCLUSION

Peritoneal cytokines, which are produced by mesothelial cells, leukocytes and ectopic endometrial cells, interwork locally and systemically in women with endometriosis. More studies about the specific role and interactions of these cytokines are needed to improve the understanding of endometriosis and to develop novel therapies.

Differential expression of interleukins (IL)-13 and IL-15 in ectopic and eutopic endometrium of women with endometriosis and normal fertile women

PROBLEM

Interleukins (IL) 13 and 15 are key regulators of inflammatory and immune responses, processes that are central to endometriosis and associated abnormalities. The present study examined (1) whether ectopic endometrial tissue expresses IL-13 and IL-15 (2) if their expression differs compared with matched eutopic endometrium and control endometrium from normal fertile women, and (3) if peritoneal fluids (PF) content of these cytokines reflects the disease compared with PF from women with peritoneal adhesions unrelated to endometriosis and those without pelvic pathology.

METHODS

The expression of IL-13 and IL-15 mRNA and protein was determined using quantitative RT-PCR, ELISA and immunohistochemistry.

RESULTS

Ectopic endometrium expresses IL-13 and IL-15 mRNA and protein with elevated levels compared with eutopic and control endometrium, irrespective of the phases of the menstrual cycle, with predominance in IL-13 expression. Endometrial epithelial cells were found to be the primary site of IL-13 and IL-15 expression. The PF content of IL-13 and IL-15 show a trend toward higher concentrations in women with adhesion and endometriosis, respectively, compared with fertile control without pelvic pathology.

CONCLUSION

Interleukins 13 and 15 are expressed in ectopic endometrium and present in PF of women with endometriosis and their elevated expression in ectopic endometrium suggests that these cytokines play a key role in local inflammatory/immune responses that are critical in endometriosis-associated abnormalities.

PPAR-gamma decreases endometrial stromal cell transcription and translation of RANTES in vitro

An important step in the monthly turnover of the endometrial lining during the menstrual cycle is the cyclical recruitment and activation of inflammatory cells. Regulated Upon Activation Normal T Cell Expressed and Secreted (RANTES) has been shown to mediate inflammatory cell chemotaxis. This study investigated the effect of PPAR-gamma ligands upon transcription and translation of RANTES in human endometrial stromal cells. First, the expression of endogenous PPAR-gamma was confirmed in endometrial stromal cells. The human RANTES promoter was searched to identify likely PPAR response elements (PPREs), in which three putative sites were found. The effect of PPAR-gamma ligands upon RANTES promoter activity and protein production was analyzed. In cells transfected with RANTES promoter vectors containing 958 bp and 3 PPREs, the addition of PPAR-gamma ligands inhibited promoter activity by 60% (P < 0.01) and 48% (P < 0.02), respectively. Truncation of the gene promoter to delete all putative PPREs abrogated the ligand-induced inhibition. Stromal cells showed a 40% decrease in RANTES protein secretion when treated with a PPAR-gamma ligand (P < 0.01). The use of PPAR-gamma ligands to reduce chemokine production and inflammation may be a productive strategy for future therapy of endometrial disorders, such as endometriosis.

Endometrial anomalies in women with endometriosis

Endometriotic lesions are defined by extrauterine growth of endometrial glands and stroma. Retrograde menstruation with subsequent attachment, invasion, and neovascularization are believed to give rise to the endometriotic lesions. As most women exhibit some degree of retrograde menstruation, some other unidentified factor(s) must render certain women susceptible to attachment and growth of ectopic endometrial tissue. A variety of theories have been proposed to account for this susceptibility, including genetic predisposition, aberrant immunological response, and an altered peritoneal environment. Ectopic endometriotic lesions are histologically similar to their putative eutopic precursors, yet significant biochemical differences exist between these two tissues. Less information is available regarding differences between eutopic endometrium from women with or without endometriosis. This report describes anomalies in structure, proliferation, immune components, adhesion molecules, proteolytic enzymes and inhibitors, steroid and cytokine production and responsiveness, and gene expression and protein production that have been identified in eutopic endometrium from women with endometriosis.

Regulated on activation, normal T-cell-expressed and -secreted mRNA expression in normal endometrium and endometriotic implants: assessment of autocrine/paracrine regulation by in situ hybridization

Chemoattraction of macrophages and T cells into the normal endometrium and inflammatory sites within endometriotic foci is mediated by chemokine gene expression. mRNA transcripts encoding regulated on activation, normal T-cell-expressed and -secreted (RANTES), a monocyte and T-cell chemokine, were demonstrated in the stroma of normal endometrium and endometriotic implants using in situ mRNA hybridization. Epithelial glands failed to express RANTES mRNA. In histological serial sections, we observed CD68-positive macrophages in the stroma of endometriotic implants adjacent to regions with prominent RANTES mRNA hybridization. In adjacent sections, monoclonal antibodies against tumor necrosis factor (TNF)-alpha showed this cytokine to be localized to stromal and epithelial compartments of the endometriotic implant with weak staining in unaffected ovarian tissue. Subconfluent monolayers of endometriotic stromal cells were tested for RANTES gene expression in situ, but we could only detect RANTES mRNA in isolated stromal cells after treatment with TNF-alpha. No RANTES mRNA was observed in unstimulated stromal cells or TNF-alpha stimulated or unstimulated epithelial cells. The data are consistent with a model in which proinflammatory cytokines (eg, TNF-alpha) induce RANTES gene expression limited to specific cells within endometrial and endometriotic stroma. Production of this chemokine, in turn, stimulates recruitment of CD68-positive macrophages into these tissues.

Induction of an angiogenic phenotype in endometriotic stromal cell cultures by interleukin-1beta

Activated peritoneal macrophages are associated with endometriosis and may play a central role in its aetiology by releasing interleukin-1beta (IL-1beta) in response to refluxed endometrium. Pari passu with the establishment of endometriotic implants is the development of a vascular supply. In this study we investigated the angiogenic properties of two endometrial proteins, vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6), and assessed their production in response to IL-1beta stimulation in human stromal cells isolated from normal endometrium (NE) and endometriotic lesions (EI). Proliferation of bovine brain capillary endothelial cells (BBCE) with a [(3)H]-thymidine incorporation assay was observed when VEGF (2.1 +/- 0.2-fold; P < 0.05) or VEGF and IL-6 (1.8 +/- 0.1-fold; P < 0.05) were added in vitro, relative to saline-treated control cultures. Northern blot analysis showed induction of VEGF mRNA (2.6-fold; P < 0.05) and IL-6 mRNA (6.3-fold; P < 0.05) transcripts in EI cells, but not NE cells, exposed to IL-1beta. A similar induction was seen with VEGF and IL-6 protein secretion in the responsive EI cells. Reverse transcription-polymerase chain reaction (RT-PCR) for the IL-1 receptor type I (IL-1 RI) indicated that the differential effects of IL-1beta on NE and EI cells was associated with 2.4 +/- 0.1-fold more receptor mRNA in EI versus NE cells. We propose that the ability of IL-1beta to activate an angiogenic phenotype in EI stromal cells but not in NE cells, is mediated by the IL-1 RI.

IFN-γ Is Produced by Polymorphonuclear Neutrophils in Human Uterine Endometrium and by Cultured Peripheral Blood Polymorphonuclear Neutrophils

Cytokines present in the human uterus play an important role both in modulating immune responses to infectious challenge and in the establishment and maintenance of pregnancy. In particular, successful implantation and pregnancy is thought to require the establishment of a Th2 environment, while Th1 cytokines are associated with pregnancy loss and infertility. On the other hand, a Th1 response appears to be required for the resolution of acute infection. Using novel confocal microscopic analysis of fresh sections of human tissue, we have investigated the production of IFN-γ, a Th1 cytokine, in human endometria. Extracellular IFN-γ, mostly associated with matrix components, was located immediately beneath the luminal epithelium and along the glandular epithelium proximal to the lumen. As evidenced by intracellular staining, IFN-γ is produced by both stromal cells and intraepithelial lymphocytes through all stages of the menstrual cycle. Surprisingly, the stromal cell containing intracellular IFN-γ was identified as a polymorphonuclear neutrophil on the basis of its reactivity with a panel of mAbs and its nuclear morphology. We further found that polymorphonuclear neutrophils isolated from normal donors produce IFN-γ in response to stimulation with LPS, IL-12, and TNF-α. Taken together, these findings suggest that polymorphonuclear neutrophils are capable of producing IFN-γ both in vitro and in vivo, indicating that their role in shaping immune responses may be more extensive than previously thought. Furthermore, these studies strongly suggest that polymorphonuclear neutrophils play an important role in determining immune responsiveness within the female reproductive tract.

Peritoneal cellular immunity and endometriosis

PROBLEM

An immunologic basis has long been considered to be very important in the pathogenesis of endometriosis. Interactions of the peritoneal cells, which comprise macrophages, B cells, T cells, natural killer (NK) cells, and retrograde endometrial cells, are critical, but remain controversial, for exploring the pathogenesis of endometriosis.

METHOD OF STUDY

Accumulated data from the literature were reviewed, and our data were analyzed.

RESULTS

The data show that peritoneal macrophages are activated by the recurrent reflux of menstrual shedding. Humoral and local endometrial autoantibodies are detected in patients with endometriosis, but B cells are not quantitatively increased. There is decreased NK cell activity in the peritoneal cavity and peripheral blood, and this decreased activity may be related to the failure to clear out the ectopic endometrial tissue. Peritoneal T cells are predominant by Th1 inflammatory cells, and these cells are impaired because of a decrease in activation (especially HLA-DR+CD4+CD3+ population) and in the production of interleukin-2. Inflammatory cytokines such as interleukin-1, interleukin-6, and tumor necrosis factor-alpha are elevated in the peritoneal fluid of women with endometriosis.

CONCLUSIONS

The peritoneal NK and T lymphocytes are suppressed in women with endometriosis, but whether these immunologic deviations are the cause or the result of endometriosis is still unclear. Further studies are required to determine what role immunologic factors play in the pathophysiology of endometriosis.

Endometriosis and infertility: new concepts

Endometriosis is a common gynecological disorder with varied symptomatology including chronic pelvic pain, dysmenorrhea, and infertility. The association of endometriosis and infertility has been recognized for years, although definite evidence of causality still eludes us. In this review, we will explore three general concepts that enhance our understanding of the cellular and molecular interactions contributing to the pathophysiology of this disorder and that have steered current research in endometriosis. First, we review evidence of a local peritoneal inflammatory process, supported by the findings of elevated cytokine and growth factor concentrations in peritoneal fluid of affected patients. Second, we propose a role for angiogenic factors in the establishment of ectopic implants. Third, we review evidence for biochemical differences of eutopic and ectopic endometrium in endometriosis patients, which may contribute to both the pathogenesis and sequelae of this important disorder. Through information derived from these research efforts, we hope to develop better therapeutic interventions as adjunctive or alternative therapies to our current medical and surgical armamentarium.

Basic research in endometriosis

A more thorough understanding of the mechanisms associated with the cause and pathophysiology of endometriosis may help in the development of new diagnostic and therapeutic methods for the management of endometriosis. Research has begun to enhance our understanding of endometriosis by demonstrating the differences and similarites between eutopic and ectopic endometrium, and by characterizing the peritoneal environment. Animal models have been developed and validated to conduct studies that are ethically impossible in women. Recently, cell culture models, using purified populations of cells from endometriotic lesions, have provided an appropriate in vitro endometriosis model to study the language by which cells communicate; to evaluate the biochemical effects of steroids, growth factors, pharmacological agents and immunomodulatory agents on the cells; and to study the effects of endometriosis on reproduction.

Decrease in interferon gamma production and impairment of T-lymphocyte proliferation in peritoneal fluid of women with endometriosis

OBJECTIVE

Our purpose was to verify regional immune modulations and to test the effect of gonadotropin-releasing hormone agonist in women with endometriosis.

STUDY DESIGN

Concentrations of peritoneal cytokines, including interleukin-1 beta, interleukin-2, soluble interleukin-2 receptor, interleukin-6, granulocyte-monocyte colony-stimulating factor, interferon gamma, and tumor necrosis factor-alpha were compared in women with and without endometriosis. Peritoneal cytokine and interleukin-2 production were examined by adding various mitogens to peritoneal fluid mononuclear cells of women with advanced endometriosis before and after gonadotropin-releasing hormone agonist treatment.

RESULTS

A significant increase in peritoneal interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha and a decrease in interferon gamma were noted in women with endometriosis. After gonadotropin-releasing hormone agonist treatment interleukin-6 decreased and interferon gamma increased. A significant impairment of interleukin-2 production of peritoneal fluid mononuclear cells by phytohemagglutinin and pokeweed mitogen stimulation was demonstrated in endometriosis, and production could be restored after gonadotropin-releasing hormone agonist treatment.

CONCLUSION

These results indicate that regional immunologic dysfunction might be invoked in the disease process of endometriosis.

The suppression of peritoneal cellular immunity in women with endometriosis could be restored after gonadotropin releasing hormone agonist treatment

PROBLEM

Our previous study reported that peritoneal natural killer (NK) cytotoxicity and CD3+CD25+ lymphocyte subpopulation were suppressed in women with advanced endometriosis. Whether these phenomena are general for all stages of endometriosis and whether these alterations could be restored by long-term use of gonadotropin releasing hormone agonist (GnRHa) are further tested in this study.

METHOD

Lymphocyte subpopulations (B cells, NK cells, T cells, and T-cell activation markers such as CD69, HLA-DR, and CD25) and NK cell cytotoxicity of peripheral blood and peritoneal fluid by dual-color flow cytometry and 51Cr release assay in 30 cases of endometriosis were compared with those in 26 controls. We also compared these changes before and after 6-month treatment with GnRHa for advanced endometriosis.

RESULTS

Compared with the controls, only those women with advanced endometriosis showed lower NK cytotoxicity in peritoneal fluid mononuclear cells (PFMC). The CD3+CD69+ lymphocyte subpopulation decreased in peripheral blood mononuclear cells (PBMC) of advanced endometriosis, while the CD3+CD25+ lymphocyte subpopulation decreased in both PBMC and PFMC of mild and advanced endometriosis. After GnRHa treatment, the CD3+CD69+ lymphocyte subpopulation increased in both PBMC and PFMC and the CD3+CD25+ lymphocyte subpopulation increased in PFMC, but not in PBMC.

CONCLUSION

Impaired local immunological function in the PF of endometriosis was confirmed by this study and the impairments could be restored after long-term GnRHa therapy.