Daniela Hornung

Is Endometriosis Associated with Systemic Subclinical Inflammation

Endometriosis is a pelvic inflammatory process with altered function of immune-related cells and increased number of activated macrophages in the peritoneal environment that secrete various local products, such as growth factors and cytokines. The elevation of cytokines and other factors in the peritoneal fluid is accompanied by the elevation of similar factors, such as CRP, SAA, TNF-α, MCP-1, IL-6, IL-8 and CCR1, in the peripheral blood of patients with endometriosis. CD44+ and CD14+ monocytes are significantly increased, while CD3+ T lymphocytes and CD20+ B lymphocytes show modest, but significant decrease in peripheral blood of women with endometriosis. This indicates that endometriosis could be viewed as a local disease with systemic subclinical manifestations. This review provides an overview of data on the changes of various factors in peripheral blood and their potential use as diagnostic tools in patients with endometriosis.

Angiogenesis and Macrophage Activation in Endometriosis

Recent studies suggest that the symptoms associated with endometriosis are the result of local peritoneal inflammation. Increased concentrations of activated pelvic macrophages and lymphocytes and the elevated levels of specific cytokines and growth factors reviewed above support this hypothesis. The precise roles of these soluble factors are currently unknown, but we propose that a complex network of endometrial cytokines are normally regulated by hormones produced during the ovulatory cycle. Ectopic endometrial implants also are subject to these same endocrine cues. The secretion of these proinflammatory proteins by endometriosis lesions into the peritoneal microenvironment appears to cause a recruitment of capillaries and activated inflammatory cells to the implant. Future therapeutic strategies directed to ameliorate the inflammatory reaction associated with endometriosis should not ignore the likely physiological actions of many of the same bioactive molecules in normal eutopic endometrial function.

Relative Expression of 1,25-Dihydroxyvitamin D3 Receptor, Vitamin D 1α-Hydroxylase, Vitamin D 24-Hydroxylase, and Vitamin D 25-Hydroxylase in Endometriosis and Gynecologic Cancers

The authors demonstrate expression of the vitamin D receptor (VDR) and its hydroxylases in the endometrium and ovaries of women with and without endometriosis and endometrial or ovarian cancer. Immunohistochemistry showed strong staining of the VDR in endometriosis and endometrial cancer, with the most intense staining in epithelial cells. The VDR mRNA was significantly increased in patients with endometrial and ovarian cancer compared to the control group. There was a significantly higher 1α-hydroxylase expression in the endometrium of patients with endometriosis compared to healthy controls. The observed differences in VDR and 1α -hydroxylase mRNA levels were maintained at the protein level. The authors found no differences in 25-OH vitamin D levels between the serum of patients with endometriosis (25.7 ± 2.1 ng/mL, n = 46) and healthy controls (22.6 ± 2.0 ng/mL, n = 33, P = .31). They hypothesize that vitamin D might influence the local activity of immune cells and cytokines thought to play important pathogenic roles in the development and maintenance of endometriosis.

The expression of estrogen receptors as well as GREB1, c-MYC, and cyclin D1, estrogen-regulated genes implicated in proliferation, is increased in peritoneal endometriosis

OBJECTIVE To analyze the expression of estrogen receptors α and β as well as their target genes implicated in proliferation, c-myc, cyclin D1, and GREB1, in the endometrium of women with or without endometriosis. DESIGN Expression analysis in human tissue. SETTING University hospitals and a clinic. PATIENT(S) Ninety-one premenopausal women (59 patients with endometriosis and 32 controls) undergoing laparoscopic surgery. INTERVENTION(S) Biopsies were obtained at time of surgery, performed during the proliferative phase of the cycle. MAIN OUTCOME MEASURE(S) Estrogen receptors α and β as well as c-myc, cyclin D1, and GREB1 mRNA expression levels were determined by quantitative reverse transcriptase-polymerase chain reaction. Tissue localization of these estrogen-regulated genes was analyzed by immunohistochemistry. RESULT(S) Estrogen receptors α and β as well as c-myc, cyclin D1, and GREB1 mRNA expression levels were increased in ectopic tissue in comparison with both normal and eutopic endometrium. Estrogen receptor mRNA levels also were upregulated in the eutopic peritoneal tissue of patients with endometriosis. Cyclin D1 and GREB1 expression was augmented in eutopic endometrium. c-myc, cyclin D1, and GREB1 proteins exhibited a nuclear localization in ectopic endometrial tissue. CONCLUSION(S) This constitutes the first report of increased expression of GREB1, as well as cyclin D1 and c-myc, in peritoneal endometriotic lesions, implicating these proteins in estrogen-dependent growth in this context.

Combination of CCR1 mRNA, MCP1, and CA125 measurements in peripheral blood as a diagnostic test for endometriosis.

This study investigated the possible use of CCR1 mRNA measurement in peripheral blood leukocytes in combination with measurements of monocyte chemotactic protein-1 (MCP-1) and CA125 protein in serum as a diagnostic test for endometriosis.The expression of CCR1 mRNA in peripheral blood leukocytes was measured by quantitative real-time polymerase chain reaction. MCP-1 and CA125 levels in serum were determined by ELISA and ECLIA.The ratio of CCR1/HPRT mRNA in peripheral blood of patients with endometriosis and adenomyosis was significantly elevated compared with women without endometriosis. Additionally, serum levels of MCP-1 and CA125 were significantly higher in patients with endometriosis. This method showed a sensitivity of 92.2%, a specificity of 81.6%, a negative predictive value of 83.3%, a positive predictive value of 92.3%, a likelihood ratio of a positive test result of 5.017, and a likelihood ratio of a negative test result of 0.096 to predict the presence or absence of endometriosis.The results imply the potential use of CCR1 mRNA, MCP-1, and CA125 protein measurements for the diagnosis or exclusion of endometriosis.

Endocrine and Paracrine Regulation of Endometrial Angiogenesis

The human endometrium is a complex tissue comprised of different cell types, including epithelial, stromal, inflammatory, perivascular, and blood vessel cells. The hormonal receptivity and distribution of these cell populations change during the menstrual cycle. Cyclical endometrial growth is dependent on its ability to regenerate a vascular capillary network, which grows in parallel with the proliferation and differentiation of the endometrial lining. Natural hormonal effects on the endometrium and endocrine manipulation of this tissue, in response to the use of exogenous steroid therapies, can affect endometrial capillary proliferation and function, leading to clinical abnormalities of uterine bleeding. We propose that the regulation of endometrial angiogenesis is mediated indirectly via complex interactions among cell types. Our laboratory has focused on a prototypical member of the angiogenic proteins, vascular endothelial growth factor (VEGF)‐A. In this paper we present data demonstrating that VEGF‐A expression in normal endometrial epithelial and stromal cells and in Ishikawa adenocarcinoma cells is increased by an ovarian steroid, estradiol. Infiltrating immune cells, particularly polymorphonuclear granulocytes, also are sources of VEGF‐A. In inflammatory conditions involving the endometrium (e.g., endometriosis), a proinflammatory cytokine, IL‐1β, can mediate neoangiogenesis by inducing VEGF‐A gene transcription. Thus, endometrial vascularization is effected by both endocrine and paracrine pathways.

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.

Peroxisome proliferator-activated receptors: new players in the field of reproduction.

Peroxisome proliferator‐activated receptors (PPAR) are members of the nuclear hormone receptor superfamily. Synthetic ligands to one family member, PPARγ, are currently widely used as treatment for chronic diseases such as diabetes type II and other insulin resistances, e.g. as seen in polycystic ovary syndrome (PCOS). Moreover, novel approaches employing knock‐out mice demonstrated that PPARγ seems to play a key role in placental and fetal development. This review describes recent insights into the role of PPARs in human reproduction with specific reference to infertility, placental maturation and fetal development as well as disturbed pregnancy. Further, we highlight the current knowledge on synthetic ligands to PPARγ used as a treatment in women with PCOS.

The molecular signature of endometriosis-associated endometrioid ovarian cancer differs significantly from endometriosis-independent endometrioid ovarian cancer

OBJECTIVE To determine whether endometriosis-associated endometrioid cancer (EAOC) is a specific entity compared with endometrioid cancer not associated with endometriosis (OC). DESIGN Case-control study. SETTING University hospital research laboratory. PATIENT(S) Seven patients with endometriosis-associated ovarian cancer EAOC and five patients each with OC, ovarian endometriosis, and benign ovaries. INTERVENTION(S) Ovarian tissue samples were collected from surgical procedures. MAIN OUTCOME MEASURE(S) We hybridized cRNA samples to the Affymetrix HG-U133A microarray chip. Representative genes were validated by real time polymerase chain reaction. RESULT(S) We identified two main groups of genes: The first group contained the genes SICA2, CCL14, and TDGF1. These genes were equally regulated in endometriosis and EAOC but not in OC and benign ovaries. The second group contained the genes StAR, SPINT1, Keratin 8, FoxM1B, FOLR1, CRABP1, and Claudin 7. They were equally regulated in EAOC and OC but not in ovarian endometriosis and benign ovaries. CONCLUSION(S) That the first group is composed of the cytokines SICA2 and CCL14 and the growth factor TDGF1 indicates that the regulation of the autoimmune system and of inflammatory cytokines may be very important in the etiology of endometriosis and EAOC. That the second group is composed of genes that play a central role in cell-cell interaction, differentiation, and cell proliferation indicates that they may be important in the development of ovarian cancer in women with endometriosis.

Apoptosis in Endometriosis

Apoptosis is a physiologic process that eradicates undesired cells without inducing an inflammatory reaction. It is an important regulator of eutopic endometrial function and evidence suggests that apoptosis aids in maintaining cellular homeostasis during the menstrual cycle by eliminating aging cells from the functional layer of the uterine endometrium. Endometriosis, which is characterized by the growth of endometrial tissue outside the uterus, could result from increased cellular proliferation or decreased apoptosis in response to appropriate stimuli. Eutopic endometrium from women with endometriosis has several differences compared with normal endometrium of women without endometriosis. These differences may contribute to the survival of regurgitated endometrial cells into the peritoneal cavity and thus to the development of endometriosis. In this article, we will summarize recent literature concerning apoptosis-related genes such as Bcl-2 and Fas, outline the molecular basis of apoptosis and review the literature focused on the alterations in regulation of apoptosis in eutopic and ectopic endometrium from women with endometriosis.