hCG stimulates angiogenic signals in lymphatic endothelial and circulating angiogenic cells.

Human chorionic gonadotropin (hCG) has long been associated with the initiation and maintenance of pregnancy, where angiogenesis plays an important role. However, the function of hCG in angiogenesis and the recruitment of vascular active cells are not fully understood. In this study, the role of hCG and its receptor in circulating angiogenic and human endothelial cells, including lymphatic, uterine microvascular, and umbilical vein endothelial cells, was examined. Immunohistochemistry and immunoblot analysis were used to detect LH/hCG receptor expression and the expression of hCG-induced angiogenic molecules. HIF-1α was determined via ELISA and downstream molecules, such as CXCL12 and CXCR4, via real-time PCR. Chemotaxis was analyzed using Boyden chambers. Our results show that the LH/hCG receptor was present in all tested cells. Furthermore, hCG was able to stimulate LH/hCG-receptor-specific migration in a dose-dependent fashion and induce key angiogenic molecules, including HIF-1α, CXCL12, and CXCR4. In conclusion, our findings underscore the importance of hCG as one of the first angiogenic molecules produced by the conceptus. hCG itself alters endothelial motility, recruitment, and expression of pro-angiogenic molecules and may therefore play an important role in vascular adaption during implantation and early placental formation.

Interferon stimulated gene 15 expression at the human embryo-maternal interface.

PURPOSE: In early pregnancy the dialogue between maternal endometrium and embryo is a key process in establishing a receptive decidua and placental network. Decidual ISG15 induction is thought to promote pregnancy maintenance and development. ISG15 is involved in RNA splicing, cytoskeletal organization, stress response and further intracellular processes. METHODS: ISG15 expression was examined immunohistologically in paraffin-embedded human placental and decidual tissue samples of all pregnancy trimesters on adjacent sections (first trimester n = 5, second n = 5, third n = 3). Samples were processed using a protocol applying a rabbit polyclonal ISG15 antibody. A mouse monoclonal cytokeratin seven antibody was utilized to identify the different placental departments and decidual glands. Staining results and anatomical features were evaluated blindly with strict rating criteria. RESULTS: ISG15 expression was identified in first and second trimester tissue samples. ISG15 localized especially to the extravillous cytotrophoblasts in the maternal wall and in maternal blood vessel. Expression was detected in cytotrophoblast progenitor cells in the placental villi and the cell column with a maximum in the first trimester. The syncytial layer stained positive in first and second trimester samples. Third trimester samples showed no expression of ISG15 at all. CONCLUSIONS: ISG15 abundance in the human placenta is an interesting finding, with implications for placental development, fetal growth and potential defense mechanism against infections. The maximal expression of ISG15 in the first and second trimester of pregnancy suggests that ISG function is needed when placental and embryo development is enormous and embryo susceptibility to external influences is high.

CXCL1 expression in human decidua in vitro is mediated via the MAPK signalling cascade.

Early molecular interaction between embryo and mother, involving chemoattractants, especially chemokine CXC-motif ligand 1 (CXCL1)(2), determines the pregnancy outcome. So far nothing is known about the signalling cascades of CXCL1 expression in human decidua. The aim of the study was to identify signalling cascades mediating the CXCL1 expression in human decidua incubated with IL-1ß as a major secretion product of the embryo. Therefore, decidualised endometrial stromal cells were incubated with IL-1ß in a concentration- and time-dependent manner. The specificity of the IL-1ß induced CXCL1 expression was verified by application of the IL-1 receptor antagonist, which opposed the binding of IL-1ß to its receptor, leading to a dose dependent diminished to complete CXCL1 elimination. IL-1ß signalling was investigated using inhibitors for MAPK, STAT3 and JNKinase cascades. The CXCL1 secretion of decidualised endometrial cells was measured by ELISA. The MAPK signalling cascade was explored by western blot analysis of ERK and NFκB p65(3) as well as phospho ERK and pp65 activation by IL-1ß in detail. A statistical significant increase in CXCL1 mRNA- and protein-expression after incubation with 0.1ng/ml IL-1ß after 48h was detected. CXCL1 protein secretion could be completely prevented by IL-1 receptor antagonist treatment. Only inhibition of the MAPKinase pathway resulted in a statistically significant decrease of CXCL1 protein secretion. Initiation of the MAPK pathway depicted by phospho ERK activation started as early as 2min after coincubation of decidualised endometrial stromal cells with IL-1ß. Activation of NFκB p65 could be measured within 15min of IL-1ß incubation in decidualised endometrial stromal cells. CXCL1 is a target for the embryos' secretion product IL-1ß in decidualised endometrial stromal cells during the peri-implantation period. IL-1ß's rapid effect on CXCL1 synthesis is uniquely mediated via the MAPK-signalling cascade and the activation of CXCL1s' transcription factor NFκB p65.

Pre-eclampsia is associated with elevated CXCL12 levels in placental syncytiotrophoblasts and maternal blood.

OBJECTIVES: Placental derived vasculogenic/angiogenic substances in maternal blood are dysregulated in pre-eclampsia. We hypothesized that CXCL12, a chemokine with vasculogenic actions, is amongst such molecules. STUDY DESIGN: CXCL12, CXCL16, CXCR4, and CXCR6 immunolocalization in placental tissue was analyzed in pre-eclampsia (n=8) in comparison to controls (n=8). CXCL12, measured by ELISA in blood, in women diagnosed with pre-eclampsia (n=14) and prior to the development of pre-eclampsia (at 20 weeks' gestation, n=20) was compared with CXCL12 concentrations in gestation-matched, healthy control subjects (n=34). RESULTS: In placental tissue, syncytiotrophoblast staining for CXCL12 was increased in pre-eclampsia. Maternal serum CXCL12 was increased in pre-eclampsia [2000 (SD 402) vs 1484 (SD 261)pg/ml, P=0.01] but not in plasma obtained at 20 weeks of gestation prior to the onset of pre-eclampsia [1183 (SD 336) vs 1036 (SD 144)pg/ml, P=0.09]. CONCLUSION: Our data suggest that the syncytiotrophoblast contributes to a pre-eclampsia-associated increase in CXCL12 levels in maternal blood. These findings support the hypothesis that an imbalance of angiogenic factors contributes to the pathogenesis of pre-eclampsia.

Expression of the vascular endothelial growth factor receptor neuropilin-1 at the human embryo-maternal interface.

OBJECTIVE: Angiogenesis is required for successful implantation of the invading blastocyst. Vascular endothelial growth factor (VEGF) is an important key player in angiogenesis and vascular remodeling during the implantation process. Besides its well-characterized receptors VEGFR1 and VEGFR2, neuropilin-1 (NRP-1) has been shown to play an additional role in the signaling process of angiogenesis in human endometrium during the menstrual cycle, as a co-receptor of VEGF. These findings led to the hypothesis that NRP-1 might play a role in the vascular remodeling process during embryo implantation and the establishment of a pregnancy. STUDY DESIGN: NRP-1 mRNA transcript and protein expression were investigated in human choriocarcinoma cell lines (JEG-3, Jar and BeWo) aiming to evaluate the expression of NRP-1 in vitro, as well as in human decidua of all three trimesters of pregnancy, by western blot analysis (three samples of each trimester of pregnancy). The localization of NRP-1 in human decidua of all three trimesters of pregnancy was analyzed by immunohistochemistry (five samples of each trimester of pregnancy). RESULTS: NRP-1 transcript and protein were expressed in all cell lines examined. Corresponding to the analysis of human tissue by western blot and the localization by immunohistochemistry, NRP-1 protein higher expressed in samples of early pregnancy in comparison to the end of pregnancy. NRP-1 was expressed in the decidua, villi and invading cytotrophoblast of all samples investigated. CONCLUSIONS: This is the first study clearly showing the expression of NRP-1 in human decidua and trophoblast, suggesting an important role for the VEGF co-receptor NRP-1 besides the established receptor VEGFR2 at the embryo-maternal interface during embryonic implantation and placentation.

Nitric oxide synthase expression and functional response to nitric oxide are both important modulators of circulating angiogenic cell response to angiogenic stimuli.

OBJECTIVE: Circulating angiogenic cells (CACs), also termed endothelial progenitor cells, play an integral role in vascular repair and are functionally impaired in coronary artery disease (CAD). The role of nitric oxide (NO) in CAC function is poorly understood. We hypothesized that CAC migration toward angiogenic signals is modulated by both NO synthase (NOS) expression and functional response to NO. METHODS AND RESULTS: Similar to endothelial cells, CAC chemotaxis to vascular endothelial growth factor (VEGF) was blocked by inhibition of NOS, phosphatidylinositol 3-kinase, or guanylyl cyclase or by treatment with an NO scavenger. Addition of an NO donor (S-nitroso-N-acetylpenicillamine) and the NOS substrate l-arginine increased random cell migration (chemokinesis) and enhanced VEGF-dependent chemotaxis. Healthy CACs expressed endothelial NOS, but endothelial NOS was not detected in CAD patient CACs. Both chemokinesis and chemotaxis to VEGF of patient CACs were decreased compared with healthy CACs but were restored to healthy values by S-nitroso-N-acetylpenicillamine. In parallel, CAD patients exhibited lower flow-mediated vasodilation and plasma NO source nitrite than young, healthy subjects, indicating endothelial dysfunction with reduced NO bioavailability. CONCLUSIONS: NOS activity is required for CAC chemotaxis. In CAD patients, impairment of NOS expression and NO bioavailability, rather than response to NO, may contribute to dysfunction of CACs and limit their regenerative capacity.

Genital schistosomiasis as a cause of female sterility and acute abdomen.

OBJECTIVE: To report the case of a Nigerian patient who suffered from sterility and underwent abdominal laparotomy to remove an adnexal tumor. Histologic analysis revealed Schistosoma haematobium ova. DESIGN: Case report. SETTING: Multidisciplinary group practice and teaching hospital. PATIENTS: One patient who underwent an abdominal laparotomy to remove an adnexal tumor. INTERVENTION(S): In vitro fertilization and adnexal tumor resection via laparotomy. MAIN OUTCOME MEASURE(S): Treatment of the adnexal tumor affecting the reproductive health. RESULT(S): Histologic analysis performed on the tissue removed at surgery revealed fibrous patches around aggregates of calcified Schistosoma haematobium eggs in the fallopian tube wall. CONCLUSION(S): Schistosomiasis needs to be considered as a differential diagnosis of female infertility and sterility.

Cytotrophoblast induction of arterial apoptosis and lymphangiogenesis in an in vivo model of human placentation.

We studied the vascular effects of invasive human cytotrophoblasts in vivo by transplanting placental villi to the fifth mammary fat pads or beneath the kidney capsules of Scid mice. Over 3 weeks, robust cytotrophoblast invasion was observed in both locations. The architecture of the mammary fat pad allowed for detailed analysis of the cells' interactions with resident murine blood vessels, which revealed specific induction of apoptosis in the endothelial cells and smooth muscle walls of the arterioles. This finding, and confirmation of the results in an in vitro coculture model, suggests that a parallel process is important for enabling cytotrophoblast endovascular invasion during human pregnancy. Cytotrophoblast invasion of the kidney parenchyma was accompanied by a robust lymphangiogenic response, while in vitro, the cells stimulated lymphatic endothelial cell migration via the actions of VEGF family members, FGF, and TNF-alpha. Immunolocalization analyses revealed that human pregnancy is associated with lymphangiogenesis in the decidua since lymphatic vessels were not a prominent feature of the nonpregnant endometrium. Thus, the placenta triggers the development of a decidual lymphatic circulation, which we theorize plays an important role in maintaining fluid balance during pregnancy, with possible implications for maternal-fetal immune cell trafficking.

Nicotine downregulates the l-selectin system that mediates cytotrophoblast emigration from cell columns and attachment to the uterine wall.

Here we show that maternal smoking downregulated, in a dose-dependent manner, cytotrophoblast expression of l-selectin and its TRA-1-81-reactive carbohydrate ligands. Cell islands -- cell columns that fail to make uterine attachments, often more numerous in the placentas of smokers -- exhibited an even greater downregulation of the l-selectin adhesion system. These effects were attributable to nicotine, since exposure of explanted villi to this drug in vitro reproduced the effects observed in situ. Videomicroscopy showed that the downstream consequences included inhibition of all stages of cytotrophoblast outgrowth from columns, including rolling adhesion within columns and generation of invasive cells at the distal ends. These results suggest that nicotine, acting through the l-selectin adhesion system, impairs the development of cell columns that connect the fetal portion of the placenta to the uterus, one possible reason why women who smoke have a much harder time achieving and sustaining pregnancy than their nonsmoking counterparts.

Towards a definition of aspirin resistance: a typological approach.

'Aspirin resistance' is a poorly defined term to describe the inability of aspirin to protect individuals from thrombotic complications and there are conflicting reports on incidence rates and clinical relevance of this phenomenon. Using collagen (1 microg/ml)-induced platelet aggregation and thromboxane formation (measured as thromboxane B(2)) in citrated platelet-rich plasma, this study demonstrates that aspirin resistance can be classified into three distinct types. In aspirin responders, both, collagen-induced platelet aggregation and thromboxane formation was completely (>95%) inhibited by oral aspirin treatment (100 mg/day). In type I resistance (pharmacokinetic type), oral treatment with aspirin was ineffective but addition of aspirin (100 microM) in vitro resulted in a complete inhibition of collagen-induced platelet aggregation and thromboxane formation. In type II resistance (pharmacodynamic type), neither oral treatment with aspirin nor addition of aspirin in vitro inhibited collagen-induced platelet aggregation and thromboxane formation. In type III resistance (pseudo-resistance), platelet aggregation was induced by a low concentration of collagen (1 microg/ml) despite of a complete inhibition of thromboxane formation by oral aspirin treatment. This typology of aspirin resistance should help to clarify the mechanisms, the actual rate, and the possible clinical consequences of this phenomenon.