ABSTRACT
Understanding of ectopic implantation within the Fallopian tube (FT) is limited. In the human uterus, the putative 'window of implantation' in the mid-luteal phase of the menstrual cycle is accompanied by increased endometrial epithelial expression of the integrins α(1)ß(1), α(4)ß(1) and α(v)ß(3) and its ligand osteopontin. Similar cyclical changes in FT integrin expression have been proposed to contribute to ectopic implantation, but supporting data are limited. In the current study, we present quantitative data on human FT transcription and translation of the integrin subunits α(1), α(4), α(V), ß(1) and ß(3) during the follicular and mid-luteal phases of the menstrual cycle, together with a supporting immuocytochemical analysis of their spatial distribution within the FT, and that of osteopontin. In contrast to previous studies, our data indicate that all five integrin receptivity markers are constitutively transcribed and translated in the FT, with no evidence for changes in their expression or distribution during the window of implantation in the mid-luteal phase of the cycle. Furthermore, we could find no evidence for cyclic redistribution of the integrin α(v)ß(3) ligand osteopontin within the FT. Although we do not rule out the involvement of integrin endometrial receptivity markers in the establishment of ectopic pregnancy, our findings do not support their differential expression during a tubal implantation window.
Subject(s)
Epithelium/metabolism , Fallopian Tubes/cytology , Fallopian Tubes/metabolism , Integrins/metabolism , Adult , Embryo Implantation/genetics , Female , Follicular Phase/genetics , Follicular Phase/metabolism , Humans , Immunohistochemistry , In Vitro Techniques , Integrin alpha1beta1/genetics , Integrin alpha1beta1/metabolism , Integrin alpha4/genetics , Integrin alpha4/metabolism , Integrin alphaVbeta3 , Integrins/genetics , Luteal Phase/genetics , Luteal Phase/metabolism , Middle Aged , Osteopontin/genetics , Osteopontin/metabolism , Pregnancy , Pregnancy, Ectopic/genetics , Pregnancy, Ectopic/metabolism , Receptors, Collagen , Reverse Transcriptase Polymerase Chain Reaction , Young AdultABSTRACT
Lymphoid and myeloid cell populations in human endometrium are well-documented and are known to play important roles in providing immune tolerance, controlling trophoblast invasion, and mediating vascular remodeling. Immune cell populations in the Fallopian tube have not been comprehensively studied. The aim of this study was to characterize lymphoid and myeloid cell populations in non-pregnant Fallopian tube and determine whether they are altered in Fallopian tube from women with ectopic pregnancy. Fallopian tube was analyzed by flow cytometry and immunohistochemistry. Populations of CD3+ (CD4+ and CD8+) lymphocytes, LIN1-HLADR+ (CD123+ and CD11c+) dendritic cells, monocytes, neutrophils, and CD56(dim)CD16- natural killer (NK) cells were demonstrated to be present in non-pregnant Fallopian tube. CD123+ dendritic cells were predominant over CD11c+ dendritic cells. Numbers of CD11c+ cells were significantly higher in the progesterone-dominant mid-luteal phase of the menstrual cycle compared with the follicular phase. Numbers of CD45+ leukocytes, CD68+ cells, and CD11c+ cells were higher in Fallopian tube from women with ectopic pregnancy compared with mid-luteal phase Fallopian tube. These data will advance our understanding of normal human Fallopian tube physiology and disorders of Fallopian tube function, such as ectopic pregnancy.
Subject(s)
Fallopian Tubes/pathology , Menstrual Cycle/immunology , Pregnancy, Ectopic/immunology , Adolescent , Adult , Antigens, CD/metabolism , Cell Separation , Dendritic Cells/immunology , Dendritic Cells/metabolism , Dendritic Cells/pathology , Female , Flow Cytometry , Humans , Immunohistochemistry , Killer Cells, Natural/immunology , Killer Cells, Natural/metabolism , Killer Cells, Natural/pathology , Lymphocytes/immunology , Lymphocytes/metabolism , Lymphocytes/pathology , Middle Aged , Myeloid Cells/immunology , Myeloid Cells/metabolism , Myeloid Cells/pathology , PregnancyABSTRACT
Fallopian tube (FT) and endometrial urocortin 1 (Ucn1) and corticotropin-releasing hormone (CRH)-receptor (CRH-R1/CRH-R2) expression were examined using quantitative real-time polymerase chain reaction (RT-PCR) and immunohistochemistry in nonpregnant and pregnant women (intrauterine, IUP; ectopic pregnancy, EP). Tubal Ucn1 messenger RNA (mRNA) expression was higher in luteal compared to follicular phase (P < .01) and equivalent to follicular phase in FT from EP. Tubal CRH-R1/CRH-R2 mRNA was lower in luteal phase (P < .05) and in FT from EP compared to follicular phase (P < .01). Ucn1 mRNA was lower in endometrium from EP compared to IUP (P < .05). Corticotropin-releasing hormone-R1 mRNA was higher in endometrium from EP compared to viable IUP (P < .05). No differences were observed in CRH-R2 expression. Corticotropin-releasing hormone-R1 protein was primarily localized to epithelium of FT and endometrium. Quantitative analysis of tubal CRH-R1 protein expression reflected that seen at the mRNA level but endometrial expression was equivocal. The demonstration of attenuated tubal/endometrial Ucn1/CRH-R expression in EP further supports a role of the CRH-family in embryo implantation.
Subject(s)
Endometrium/metabolism , Pregnancy, Tubal/metabolism , Receptors, Corticotropin-Releasing Hormone/biosynthesis , Urocortins/biosynthesis , Adult , Female , Humans , Immunohistochemistry , Menstrual Cycle/metabolism , Pregnancy , RNA/chemistry , RNA/genetics , Receptors, Corticotropin-Releasing Hormone/genetics , Reverse Transcriptase Polymerase Chain Reaction , Urocortins/genetics , Young AdultABSTRACT
We investigated whether the repulsive SLIT/ROBO pathway is expressed in the endometrium and is negatively regulated during implantation. We also examined whether deficient expression in the Fallopian tube (FT) may predispose to ectopic pregnancy (EP). Endometrium (n = 21) and FT (n = 17) were collected across the menstrual cycle from fertile women with regular cycles. Decidualized endometrium (n = 6) was obtained from women undergoing termination, and FT (n = 6) was obtained from women with EP. SLIT/ROBO expression was quantified by reverse transcription-PCR and protein localized by immunohistochemistry. The regulation of SLIT/ROBO expression in vitro, by sex steroids and hCG, was assessed in endometrial (hTERT-EEpC) epithelial cells, and the effects of Chlamydia trachomatis infection and smoking were studied in oviductal (OE-E6/E7) epithelial cells. Endometrial SLIT3 was highest in the mid-secretory phase (P = 0.0003) and SLIT1,2 and ROBO1 showed a similar trend. ROBO2 was highest in proliferative phase (P = 0.027) and ROBO3,4 showed a similar trend. SLIT2,3 and ROBO1, 4 were lower in decidua compared with mid-secretory endometrium (P < 0.05). SLITs and ROBOs, excepting ROBO2, were expressed in FT but there were no differences across the cycle or in EP. SLIT/ROBO proteins were localized to endometrial and FT epithelium. Treatment of hTERT-EEpC with a combination of estradiol and medroxyprogesterone acetate inhibited ROBO1 expression (P < 0.01) but hCG had no effect. Acute treatment of OE-E6/E7 with smoking metabolite, cotinine, and C. trachomatis had no effect. These findings imply a regulated role for the endometrial SLIT/ROBO interaction during normal development and pregnancy but that it may not be important in the aetiology of EP.
Subject(s)
Endometrium/metabolism , Fallopian Tubes/metabolism , Nerve Tissue Proteins/metabolism , Receptors, Immunologic/metabolism , Signal Transduction/genetics , Cells, Cultured , Chlamydia Infections/metabolism , Decidua/metabolism , Embryo Implantation/physiology , Female , Gene Expression Regulation/drug effects , Genetic Predisposition to Disease , Humans , Intercellular Signaling Peptides and Proteins/analysis , Intercellular Signaling Peptides and Proteins/genetics , Intercellular Signaling Peptides and Proteins/metabolism , Nerve Tissue Proteins/analysis , Nerve Tissue Proteins/genetics , Pregnancy , Pregnancy, Ectopic/genetics , Pregnancy, Ectopic/metabolism , Receptors, Cell Surface/analysis , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism , Receptors, Immunologic/analysis , Receptors, Immunologic/genetics , Risk Factors , Signal Transduction/drug effects , Smoking/adverse effects , Roundabout ProteinsABSTRACT
BACKGROUND An ectopic pregnancy is a pregnancy which occurs outside of the uterine cavity, and over 98% implant in the Fallopian tube. Tubal ectopic pregnancy remains the most common cause of maternal mortality in the first trimester of pregnancy. The epidemiological risk factors for tubal ectopic pregnancy are well established and include: tubal damage as a result of surgery or infection (particularly Chlamydia trachomatis), smoking and in vitro fertilization. This review appraises the data to date researching the aetiology of tubal ectopic pregnancy. METHODS Scientific literature was searched for studies investigating the underlying aetiology of tubal ectopic pregnancy. RESULTS Existing data addressing the underlying cause of tubal ectopic pregnancy are mostly descriptive. There are currently few good animal models of tubal ectopic pregnancy. There are limited data explaining the link between risk factors and tubal implantation. CONCLUSIONS Current evidence supports the hypothesis that tubal ectopic pregnancy is caused by a combination of retention of the embryo within the Fallopian tube due to impaired embryo-tubal transport and alterations in the tubal environment allowing early implantation to occur. Future studies are needed that address the functional consequences of infection and smoking on Fallopian tube physiology. A greater understanding of the aetiology of tubal ectopic pregnancy is critical for the development of improved preventative measures, the advancement of diagnostic screening methods and the development of novel treatments.
