Uwe Lang

Angiogenesis and vasculogenesis in pregnancy

An adequate nutrient and substrate supply is essential for normal intrauterine development of the fetus. Disturbances in uterine blood supply are associated with higher perinatal morbidity and mortality caused by preterm delivery, pre-eclampsia or intrauterine growth restriction. Adaptation of the uterine vasculature to the rising needs of the fetus occurs through both vasodilation and development of new vessels. Angiogenesis is the process of neovascularization from pre-existing blood vessels in response to hypoxia or substrate demands of tissues. The endometrium, decidua and placenta are sources rich of angiogenic growth factors. In general, the angiogenic process is initiated by growth factors such as bFGF, VEGF, or placental growth factor (PlGF). Through a complex signal transduction machinery mediated by respective receptor-tyrosine kinases, an increase in the permeability of the maternal vessels is achieved to permit growth and invasion of endothelial cells. Their chemotactic migration, formation of a vessel lumen, and functional maturation of new capillaries complete the angiogenic process that involves the expression of specific adhesion receptors and extracellular matrix-degrading proteases. During vasculogenesis, endothelial progenitor cells--angioblasts--form a primitive vascular network. This process occurs mainly during fetal development, although recruitment of angioblasts from bone marrow and peripheral blood in response to ischemic insult have been described in adults. Our recent data indicate a novel function for human chorionic gonadotropin (hCG), a hormonal factor of trophoblastic origin in uterine adaptation to early pregnancy as well as in tumor invasion and underline the importance of hCG as an yet unrecognized angiogenic factor. Although there are striking similarities between, on the one hand, tumor invasion and tumor-induced vascularization and, on the other hand, trophoblast invasion and placental development, our understanding of the different molecular and functional aspects of these two different processes, in particular, the self-limitation of the trophoblastic invasion and vessels formation during gestation might allow the establishment of new therapeutic strategies for the treatment of both tumor and pregnancy related pathology.

Uterine blood flow--a determinant of fetal growth.

An adequate increase of uterine blood flow throughout gestation is essential for uterine, placental and fetal growth. Maternal cardiovascular adaptation has to provide the uterine perfusion that is necessary to meet the requirements of the developing and growing fetus by providing transport of nutrients and oxygen to the placenta and the fetus. Thus, uterine blood flow is inextricably linked to fetal growth and survival. Reductions of uterine blood flow can occur under acute or chronic conditions or in a combination of both. Chronic reductions of uterine blood flow can be observed in pregnancy-induced hypertension (PIH), diabetes mellitus in pregnancy and intrauterine growth restriction (IUGR). Chronic restrictions in uterine blood flow will elicit a placental and fetal response in the form of growth adaptation to the reduced supply of oxygen and nutrients to the conceptus. If compensatory growth restriction reaches its limits intrauterine fetal distress can ensue. Among the great number of experimental models of intrauterine growth restriction, those involving a generalized reduction in the uteroplacental blood supply are of significance to questions relating to human pregnancy. Despite physiological differences, particularly with regard to maternal metabolism and placentation, the occlusion model in the pregnant sheep is suitable for investigating questions about fetal and placental growth.

Invasion of cytotrophoblastic JEG-3 cells is stimulated by hCG in vitro.

Trophoblast invasion into the uterine wall is controlled by many factors. Previously, a human chorionic gonadotropin (hCG) receptor has been found to be expressed on invasive trophoblast as well as on choriocarcinoma cells implying a possible role for the hormone in trophoblast invasion. Therefore, this study examined the role of hCG in the invasion of trophoblastic (JEG-3) cells. Increasing hCG concentrations were applied in a trophoblast invasion model, JEG-3, through matrigel-coated filters. The proliferation was quantified by WST-1 cleavage assay. Cell migration was studied by examining the number of cells that had passed the uncoated porous (8-microm pore size) filters. After staining, filters were examined microscopically for cells on the underside of the membrane. A quantitative protease assay was also performed. Flow cytometric analysis of alpha5 and alpha6 integrin subunits, which are essential for interactions between cells and extracellular matrix, was performed. hCG increased significantly (P<0.01) the in vitro invasion of trophoblastic JEG-3 cells in a dose-dependent manner. Migration was also increased by hCG (P<0.01). However, cell proliferation remained unchanged. The second messenger analogue dibutyryl cAMP (db cAMP) and the cAMP elevating factor (forskolin) mimicked the effects of hCG by stimulating a dose-dependent increase of trophoblastic cell UEG-3) invasion. The collagenolytic activity of trophoblastic cells (EG-3) was increased by hCG stimulation. No changes were shown in the expression of alpha5 and alpha6 integrin subunits on JEG-3 cells. In vitro hCG is a regulatory factor of invasion and migration in trophoblastic JEG-3 cells, whereas proliferation is not influenced. The endogenous production of hCG by the trophoblast in vivo implies an autocrine control of invasion processes by hCG.

Invasion of Cytotrophoblastic (JEG‐3) Cells Is Up‐Regulated by Interleukin‐15 In Vitro

PROBLEM: Trophoblast invasion into the uterus is controlled by many factors. Some cytokines (interleukin [IL]‐1, IL‐6, and IL‐10) have been shown previously to play an important role in placentation. The human placenta is an important source of IL‐15, although the cellular source of IL‐15 in the placenta has not yet been specified. IL‐15 influences cell adhesion and migration by redistributing adhesion molecules in lymphocytes and has been shown to have effects on endothelial cells and in some human tumors.

Estrogen-induced increases in coronary blood flow are antagonized by inhibitors of nitric oxide synthesis

OBJECTIVE Estrogen receptors have been found in coronary arterial endothelial and vascular smooth muscle cells. Therefore the present study was designed to determine if estradiol-17 beta can increase coronary blood flow and if so whether the changes are mediated by nitric oxide. STUDY DESIGN Five oophorectomized non-pregnant sheep were chronically instrumented to measure blood pressure, heart rate, cardiac output, left circumflex coronary blood flow and central venous pressure. Animals received estradiol-17 beta (1.0 micrograms/kg) and cardiovascular responses were followed for 135 min. RESULTS Estradiol-17 beta (1.0 micrograms/kg) increased left circumflex (coronary) blood flow 28 +/- 3%, cardiac output 15 +/- 1% and heart rate by 13 +/- 3%. Coronary vascular resistance decreased 23 +/- 5%, systemic vascular resistance decreased by 12 +/- 2% while blood pressure did not change significantly. Administration of the nitric oxide synthetase inhibitor L-nitroarginine methylester (L-NAME), had no effect on basal coronary blood flow but completely reversed estradiol-17 beta induced increases in coronary blood flow. CONCLUSION These results demonstrate that estrogen increases coronary blood flow in the non-pregnant sheep and that L-NAME, an inhibitor of nitric oxide, is able to reverse the estrogen induced flow changes.

Term breech and long-term morbidity — cesarean section versus vaginal breech delivery

STUDY Perinatal morbidity and mortality of term fetuses have been discussed extensively both for vaginal breech delivery and cesarean section. However, information regarding long-term morbidity and psychomotoric development of these children are scarce. DESIGN Data of 154 children delivered after breech presentation at our institution between 1988 and 1994 were analyzed using a specific, standardized questionnaire (Enzephalopathiefragebogen, Meyer-Probst) with emphasis on psychomotoric development and skills. Hyperkinetic disorders, social adaptation, emotional instability, and intelligence were evaluated as subcategories and compared to perinatal data. RESULTS pO(2) and base excess (BE) in the umbilical artery were lower in the vaginal group. pH, body weight and placental weight showed no difference between groups. Psychomotoric development and skills did not differ between children delivered vaginally or abdominally. Perinatal variables did not allow a prediction of long-term morbidity. CONCLUSION Route of delivery has negligible influence on the measured values in the umbilical artery and no influence on long-term morbidity of fetuses presenting breech.

Epidermal cyst of the clitoris: a rare cause of clitorimegaly

Epidermal cysts are slowly growing, intradermal or subcutaneous tumors with a wall composed of true epidermis. They occur most commonly on the face, scalp, neck, and trunk. We report the unusual case of a 16-year-old girl with an epidermal cyst of the clitoris. The tumor was removed by local excision.

Expression of Cell Adhesion Molecules in the Extravillous Trophoblast Is Altered in IUGR

PROBLEM: The invasion of trophoblast cells into the uterine wall and its arterial system is essential for the normal development of pregnancy. Cell adhesion molecules (CAM), such as the immunoglobulin superfamily and integrins, play a crucial role in a number of immunological reactions and in the invasion of the human trophoblast. Intrauterine growth restriction (IUGR) has been associated with abnormal trophoblast invasion. Therefore, the expression of CAM in the extravillous trophoblast of pregnancies complicated by IUGR might be different from normal pregnancies.

Local and systemic tolerability of magnesium sulphate for tocolysis.

An open-label, randomised, parallel-group, study was conducted in three study centres in women with premature labor and indication for a single agent intravenous tocolysis therapy with magnesium sulphate. The aim of this study was to examine the local and general tolerability and side-effects of magnesium sulphate for tocolysis. Furthermore, we tested the tolerability of a ready-for-use magnesium solution. No measurements of efficacy were performed during this study. Initially, patients received a loading dose of 4.0 g magnesium sulphate administered over 30 min. Thereafter, a continuous intravenous infusion of 1-2 g magnesium sulphate per hour up to 21 days was given. Venous score (Maddox), vital signs, adverse events as well as general tolerability (assessed by investigator and patients) and blood parameters were assessed. We showed good local and systemic tolerability of high dose magnesium sulphate for tocolysis. Only seven patients (15%) were withdrawn from the study prematurely due to minor adverse events. Potential serious complications of MgSO(4) such as respiratory arrest or clinically relevant respiratory depression were not observed. The most frequently reported local adverse events were injection site pain, itching, erythema, swelling, induration and palpable venous cord. The most common systemic adverse events considered to be possibly related to the study drugs involved the nervous system (dizziness) followed by the digestive system (nausea, constipation). Systolic and diastolic blood pressure changed only slightly during the treatment. Respiratory rate and body temperature remained stable also. Toxic magnesium levels (>2.5 mmol/l) were not observed. The assessment of the clinical investigators with regard to tolerability was very good or good in 72.5% of the patients. The introduction of the ready-to-use solution has the advantage of eliminating the need to mix the solution prior to administration. This means a lower risk of overdose and contamination.

Elevated interleukin-10 and sex steroid levels in peritoneal fluid of patients with ovarian hyperstimulation syndrome.

BACKGROUND The ovarian hyperstimulation syndrome (OHSS) following ovulation induction is characterized by a cystic enlargement of the ovaries with an acute third space fluid sequestration. Inflammatory cytokines mediate the inflammatory response (IL-1, IL-2, IL-6, IL-8, TNFalpha) and play a crucial role in the pathogenesis of OHSS. OBJECTIVE To determine the role of the anti-inflammatory cytokine interleukin-10 (IL-10) in OHSS and to examine its correlation with 17beta-estradiol and progesterone. STUDY DESIGN Peritoneal fluid and serum samples were collected from 9 patients with severe OHSS after ovulation induction by administration of GnRH-analogues followed by hMG (n=5) or recombinant FSH (n=4). Patients (n=19) without pathological findings at laparoscopy served as non-pregnant controls and pregnant women (n=14) between 7 and 16 weeks of gestation served as positive controls. Samples were assayed for IL-10 by commercially available ELISA and for for 17beta-estradiol and progesterone by RIA. Statistical analysis was performed by non-parametric Mann-Whitney U-test and results are presented as the median and range. RESULTS OHSS patients had significantly higher peritoneal fluid IL-10, 17beta-estradiol and progesterone levels than patients during early pregnancy and than the control group. No correlation was found between peritoneal fluid or serum IL-10 and 17beta-estradiol or progesterone in the different groups. Serum 17beta-estradiol and progesterone, but not serum IL-10 levels were elevated in OHSS and during early pregnancy. CONCLUSIONS High concentrations of IL-10 in peritoneal fluid suggest a role of this anti-inflammatory cytokine during OHSS. 17beta-estradiol and progesterone were elevated in peritoneal fluid and serum during OHSS but no correlation with IL-10 concentrations was found. Therefore, we assume that IL-10 has a role in OHSS as a local mediator of inflammation, however, it presents different aspects of the OHSS than the sex steroids 17beta-estradiol and progesterone.