PREECLAMPSIA, AUTOIMMUNITY AND THE AT1 RECEPTOR

Preeclampsia (PE) is a disease of late pregnancy characterized by maternal hypertension and proteinuria. It is associated with preterm delivery and significant perinatal morbidity and mortality. Despite affecting ~7% of first pregnancies, there is no effective screening method to identify women at risk, nor is there a definitive treatment other than delivery of the baby and placenta. Though the pathogenesis of PE remains unclear, an imbalance in the renin-angiotensin and immune systems are thought to be major contributors. Bridging these two concepts, it has recently been shown that women with PE harbor specific autoantibodies: the angiotensin II type 1 receptor activating autoantibody (AT1-AA). These autoantibodies act as angiotensin II and stimulate the ubiquitous AT1 receptor. To elucidate the role of AT1-AA in the pathophysiology of PE, a model of adoptive transfer was generated wherein AT1-AA isolated from human sera are injected into pregnant mice. This autoantibody incites the key features of the disease in pregnant mice: increased blood pressure, proteinuria, renal and placental abnormalities and increases in the anti-angiogenic factors soluble fms-like tyrosine kinase (sFlt-1) and soluble endoglin (sEng). These experiments were also carried out in non-pregnant animals who did not share the same symptoms. This suggests that pregnancy is a requirement for the full spectrum of preeclamptic features. In addition, the placentas and fetuses of AT1-AA-injected mice are reduced in size. The pups demonstrated intrauterine growth restriction (IUGR) and organ immaturity, especially in their kidneys and livers. To elucidate the mechanism by which these preeclamptic symptoms arise in the mouse model, the effects of increased inflammation were investigated. A multi-analyte screen indicated that the autoantibody induced inflammatory cytokines. TNF-alpha, a potent pro-apoptotic cytokine, known to be increased in both the sera and placentas of preeclamptic women, was most elevated, and was therefore the focus of further research. When incubated with AT1-AA, human placental explants greatly increased their production of TNF-alpha. In addition, TNF-alpha-mediated apoptosis was increased due to AT1-receptor activation in both the mouse placenta and human villous explants. Autoantibody-induced apoptosis and TNF-alpha production could be specifically reduced by co-treatment of AT1-AA with an anti-TNF-alpha antibody, losartan (an AT1 receptor blocker) or an antibody-neutralizing peptide, 7-aa. In order to test the pathophysiologic relationship between AT1-AA and TNF-alpha in vivo, the established adoptive transfer mouse model was employed. Co-injection of AT1-AA and an anti-TNF-alpha antibody reduced the features of PE in pregnant mice, implying an important pathogenic role for this cytokine. Overall, when injected into pregnant mice, AT1-AA induces the clinical features of PE and results in increased TNF-alpha production, placental apoptosis and fetal anomalies. Blockade of these features can be partially diminished by anti-TNF-alpha treatment, an AT1 receptor blocking drug, or a peptide which specifically neutralizes autoantibody action. Significantly, these findings could lead to a screening tool for preeclampsia as well as a potential therapeutic strategy for this life-threatening disease of mother and child

Beta-adrenergic Blockade Via Atenolol and Its Effects on Blood Pressure, Heart Rate, and Renal Morphology in the Developing Chicken Gallus Gallus Domesticus

Chicken embryos were chronically exposed to the ?1- blocker atenolol during one of three stages: mesonephros (E7-E9), mesonephros-metanephros (E11-E13), or metanephros (E15-E17). Mesonephros group hearts were larger than all other groups (P < 0.01). Mesonephros and metanephros group kidneys were larger than all remaining groups (P < 0.0001). The mesonephros group nephron number was ~40% lower than control values (P = 0.002). Glomerular areas were 26% and 18% larger than the control group in the mesonephros and metanephros groups, respectively (P < 0.001). These data suggest an E7-E9 critical window of cardiovascular and renal development for atenolol. Acute atenolol exposure in E15 embryos showed an increase in mean arterial pressure with all but the highest dose. All doses significantly decreased heart rate

Fetal heart and hemodynamics in diabetic pregnancy - Fetal cardiac and placental function in a rat model of maternal hyperglycemia and human type 1 diabetic pregnancies

Maternal type 1 diabetes mellitus affects fetal and offspring health. We aimed to investigate fetal cardiac and placental function in a rat model of maternal pregestational hyperglycemia, and the effect of gestational hyperglycemia on the offspring heart. In human fetuses of diabetic mothers the aim was to investigate, whether maternal insulin therapy will ameliorate fetal cardiac, hemodynamic, and placental abnormalities. Fetal cardiac and placental ultrasonography, histology, and gene expressions were examined in streptozotocin-induced maternal hyperglycemia and control rats. Rat off-spring cardiac genes and histology were analyzed up to two weeks after birth. In diabetic and healthy human pregnancies, fetal ultrasonography and biochemical markers of cardiac function and fetal hypoxemia, and placental morphology and gene expression were collected. In rat fetuses of maternal hyperglycemia, signs of diastolic dysfunction persisted throughout the second half of pregnancy, and transient mid-pregnancy cardiac dysfunction was observed. Increased myocardial cell turnover with cardiac hyperplasia and abnormal myocardial gene expression patterns were found. Increased placental vascular impedance and placental morphologic abnormalities were observed in the rat fetuses of maternal hyperglycemia. In the newborn rats of maternal hyperglycemia, cardiac genes controlling contractility, growth, structure, and metabolism were differently expressed when compared to healthy newborn rats. In human diabetic pregnancies, fetal cardiac output was decreased, pulsatility of the aortic isthmus blood flow velocity waveform, and fetal serum concentrations of natriuretic peptides and troponin T were increased at near term. The rat model shows that maternal hyperglycemia leads to diastolic dysfunction and placental insufficiency. Abnormal expression of genes involved in cardiac contractility, structure, growth, and metabolism were seen in late term fetal and offspring hearts. In human maternal diabetes, fetal cardiac output is decreased with biochemical evindence of myocardial dysfunction.Diabeetikon sikiön verenkierto – Sikiön sydämen ja istukan toiminta äidin hyperglykemian kokeellisessa eläinmallissa ja tyypin 1 diabeetikoiden raskauksissa Tyypin 1 sokeritauti (T1DM) vaikuttaa sikiön ja jälkikasvun hyvinvointiin. Tämän tutkimuksen tarkoituksena oli tutkia kokeellisen eläinmallin avulla emon raskaudenaikaisen hyperglykemian vaikutusta sikiön sydämen ja istukan toimintaan sekä jälkeläisten sydämen kehitykseen. T1DM naisten raskauksissa tavoitteena oli tutkia insuliinihoidon vaikutusta sikiön sydämen, verenkierron ja istukan poikkeavuuksiin. Streptozotosiinilla (STZ) aikaansaatiin emon hyperglykemia. STZ- ja verrokkirottien sikiöiltä tutkittiin sydämen ja istukan verenkiertoa ultraäänitutkimuksella, sekä kudosten histologiaa ja geenien ilmentymistä. Rotanpoikasten sydänten histologia ja geenien ilmentyminen tutkittiin 2 viikkoa syntymän jälkeen. Potilasmallissa sikiön verenkiertoa tutkittiin ultraäänellä, jonka lisäksi sydämen toiminnan ja hapenpuutteen sekä istukan rakenteen ja geenien ilmaisua selvitettiin. Koe-eläinmallissa hyperglykemialle altistuneiden sikiöiden sydämen diastolinen toiminta oli poikkeava ja keskiraskaudessa havaittiin ohimenevä sydämen vajaatoiminta. Sydämen hyperplasia, runsaat mitoottisten ja apoptoottisten solujen määrät ja poikkeava geenien ilmentyminen todettiin hyperglykeemisten emojen sikiöillä. Tämän ryhmän istukan verenkierron impedanssi oli koholla ja rakenteet poikkesivat terveiden verrokkien poikasista. Hyperglykeemisten rottien poikasilla sydämen kontraktiliteettiin, kasvuun, rakenteeseen ja aineenvaihduntaan liittyvien geenien ilmentyminen oli poikkeavaa terveiden emojen poikasiin verrattuna. Potilasmallissa T1DM-äidin sikiön sydämen minuuttitilavuus oli alentunut, ja aortan istmuksen ja alaonttolaskimon verenvirtauksen vastus ja sikiön seerumin natriureettisten peptidien ja troponiini T:n pitoisuudet olivat koholla. Kokeellisessa eläinmallissa totesimme, että emon hyperglykemia johtaa sikiön sydämen diastolisen toiminnan poikkeavuuteen ja istukan vajaatoimintaan. Sydämen kontraktiliteettiin, rakenteeseen, kasvuun ja metaboliaan liittyvien geenien ilmentyminen oli poikkeava sikiöillä ja vastasyntyneillä poikasilla. Äidin nuoruustyypin sokeritauti johtaa sikiön sydämen minuuttitilavuuden laskuun ja biokemiallisiin muutoksiin, jotka liittyvät sydämen toimintahäiriöön.Siirretty Doriast

Maternal High Fat Nutrition is Associated with Placental Dysfunction: Insight in Pathophysiology and Potential Mechanisms

The prevalence of overweight (BMI >25 kg/m²) and obesity (BMI >30 kg/m²) are increasing on a global scale, and as a consequence, obesity among women of reproductive age has also increased within the last decades. Obesity before and during pregnancy is associated with a higher risk for the mother and the unborn child to develop pregnancy related complications, including gestational diabetes and disturbed fetal growth. Abnormal fetal growth has been linked to placental dysfunction and can translate into childhood and adolescence health issues, resulting in high socio-economic costs. Obesity and pregnancy are both linked to a state of increased inflammation and oxidative stress, which in case of pregnancy may be relevant to initiate the birth process at the end of pregnancy, but concomitant with obesity, can also attribute to placental dysfunction. The placenta provides essential tasks during pregnancy in both oxygen and nutrient supply, as well as waste removal and contributes to the success of pregnancy also by the production of hormones. In order to properly fulfill its function, placental cell homeostasis, structure and vascularization are of tremendous importance. However, it is still not fully understood how maternal obesity (MO) affects placental cells and processes like vascularization and placental transfer capacity. Therefore, we aimed to decipher the effects of MO on the placental feto-maternal transfer zone which constitutes the interface for transport of oxygen, nutrients and removal of waste products between maternal and fetal circulation. In order to address these questions, we induced obesity in C57BL/6N mice via feeding a high fat diet (HFD) after weaning until the end of the experiment and collected serum, placentas and epigonadal white adipose tissue (egWAT) for analyses at various gestation days (E11.5, E15.5 and E18.5). Lean mice, receiving a standard diet (SD), served as control. We discovered that in obese dams, gestation was prolonged for about 1 day compared to lean dams, and speculate that this might be due to a reduced leukocyte-infiltration of placentas and pro-inflammatory factor expression in egWAT of obese dams compared to lean dams shortly before parturition (E18.5). Furthermore, in our mouse model of maternal obesity, embryos of obese dams developed an intrauterine growth restriction (IUGR) at the beginning of the third trimester of gestation (E15.5). At the same time, protein and mRNA level of endothelial cell (EC) marker were reduced in placentas, and stereological analysis revealed impaired vascularization in placentas of obese dams. This was accompanied by increased EC senescence in the transfer zone of placentas under MO. We also found elevated interleukin-6 (IL-6) level in maternal serum and observed a trend towards an increase in IL-6 mRNA and protein level in egWAT of obese dams compared to controls, suggesting this tissue as the source of elevated circulating IL-6 level. In cell culture assays using human placental EC, we then confirmed that stimulation with IL-6 can induce senescence, suggesting a link between elevated serum IL-6 level, placental EC senescence and impaired placental vasculature. Based on the findings regarding IL-6 induced EC senescence in vitro and altered placental vascularization in vivo, we subjected obese dams to an anti-IL-6 signaling antibody therapy. We found that under this therapy, placental IL-6 protein level were elevated and down-stream signaling marker level seemed reduced, which indicates successful IL-6 signaling blockade. However, antibody therapy did not prevent lower fetal weight at E15.5, and placental vascular marker level were reduced compared to obese controls without antibody therapy. In summary, anti-IL-6 signaling therapy may not alleviate HFD-induced defects in placental vascularization and IUGR, and warrants further investigation with additional dosing. Proteomic profiling of the feto-maternal transfer zone moreover revealed a reduced level of the adherens junctions (AJ) marker E-cadherin in obese compared to lean dams at E15.5. This was confirmed in whole placenta lysates of obese compared to lean dams concomitant with a strong tendency towards reduced β-catenin level, an intracellular adaptor protein of AJ. These changes persisted until the end of pregnancy (E18.5) in placentas of obese dams, while at mid-gestation (E11.5) we could not observe altered AJ marker level. In addition, it was found that at E15.5 the ultrastructure and cell homeostasis in the transfer zone were affected by MO, as demonstrated by defective syncytial fusion and a disrupted basement membrane. In functional assays we then showed that passive transfer across the placenta was significantly increased under MO, while active glucose transport was unaltered at E15.5. Moreover, our in vitro studies suggest that fatty acids, present in excess in our HFD, can alter trophoblast cell layer permeability and cause reduced β-catenin level. Collectively, these findings strongly suggest that MO causes disruptions in the feto-maternal transfer zone via disturbed EC and trophoblast homeostasis, leading to a “leaky” placental barrier while embryos develop an IUGR. A healthy lifestyle with limited intake of fatty acids and prevention of obesity in women of childbearing age could therefore, in case of pregnancy, support proper placental function and reduce the risk of fetal growth restriction

Glucocorticoids

As one class of the most important steroid hormones, glucocorticoids have long been recognised and their therapeutic benefits have been widely used in clinical treatment, especially in anti-inflammation cases. Glucocorticoids regulate various processes in the body including the mobilization of energy stores, immune functions, gene expression, and maintenance of the homeostasis as well as the stress response, this is not surprising that the concept of "glucocorticoids" is mentioned in almost all medical text books that focus on specific organs or systems such as the cardiovascular system, the immune system, and the neuroendocrine system. The book of Glucocorticoids - New Recognition of Our Familiar Friend aims to introduce the latest findings relating to glucocorticoids, either freshly from the laboratory or from clinical case studies, and to open up a new angle of looking at the issue of balancing the therapeutic benefits and side effects brought up by glucocorticoids

Exploring novel applications for ursodeoxycholic acid in the treatment of cardiovascular conditions

As a bile acid, ursodeoxycholic acid (UDCA) is found endogenously formed in humans and other mammals where it is primarily involved in lipid metabolism. It is approved under a number of different brand names for the treatment of gallstones and Primary Billiary Cholangitis (PBC). Previous studies in cardiac cell models of Intrahepatic Cholestasis of Pregnancy (ICP) have demonstrated that UDCA can also be protective against the conduction slowing effects of the bile acid, taurocholic acid (TC). Therefore, this thesis aimed to identify novel applications for UDCA in the treatment of fetal arrhythmiasin ICP. It describes the development of a novel isolated-perfused neonatal rat heart model as a model of the fetal heart (FH) and an adult female rat heart model as a model of the maternal heart (MH) for evaluating the mechanism of bile acid induced arrhythmias. Using optical mapping and electrocardiogram (ECG) recording techniques, it separately evaluated TC effects in the atria and ventricles of the FH and compared them to effects in the MH model. It also evaluated the effects of UDCA in ischemia in a pilot study. It was observed that TC treatment induced significant conduction slowing in both the atria (ECG PR interval prolongation) and ventricles of the FH, but as occurs in ICP, these effects were absent or less pronounced in the MH model. Interestingly, co-administration of UDCA with TC was protective as it inhibited the observed conduction slowing effects. Using selective cardiac calcium channel blockers, it demonstrated that the conduction slowing effects of TC were mediated by blockade of the T-type calcium channel subtype. This was confirmed using the patch clamp technique that demonstrated that TC reduces the calcium current amplitude in neonatal rat and adult human fetal cardiomyocytes and this effect was inhibited with UDCA treatment. No beneficial effects were identified for UDCA in the treatment of acute global ischemia.Open Acces

Endothelin-1 and Hypoxic Vascular Remodeling in Ovine Fetal Cerebral Arteries

Intrauterine hypoxia resulting from decreased maternal oxygen uptake, insufficient oxygen carrying capacity, or compromised oxygen delivery to the fetus jeopardizes fetal oxygen delivery, detrimentally affecting growth and development of the immature vasculature. Hypoxia transiently increases Hypoxia Inducible Factor-1α (HIF- 1α), which complexes with HIF-1β to form the active HIF-1 dimer that can affect transcription. This temporary rise in HIF-1 can promote gene transcription of ligands such as Vascular Endothelial Growth Factor (VEGF) and Endothelin-1 (ET-1), which rises and falls with HIF levels. The absence of chronic elevation of these ligands prompted the question of how long-term effects of hypoxia is sustained. Results suggest that in addition to stimulating transient rises in ligand levels, hypoxia alters receptor expression and coupling of these ligands to the intracellular kinases. Endothelin-1 (ET-1) is an established vasoconstrictor that can activate ETA or ETB receptors, respectively stimulating vasoconstriction and vasodilation. ET-1 activates pathways such as Protein Kinase C (PKC), Ca2+/Calmodulin-Dependent Protein Kinase (CaMK), p38, and MEK/ERK, which are involved in cellular growth, proliferation, and differentiation. Our results demonstrate that chronic hypoxia altered ovine fetal cerebrovascular reactivity to ET-1 but not plasma ET-1 levels or ETA receptor cerebrovascular expression. However, chronic hypoxia enhances ET-1-induced contractility in an ETAdependent manner in Middle Cerebral Arteries (MCAs). ET-1 also exerts trophic effects on ovine fetal cerebrovasculature in organ culture in a PKC-dependent manner by inducing hypertrophy and increasing medial thicknesses, more in normoxic than hypoxic MCAs. ET-1-induced increase in arterial wall thickness is mediated by CaMKII and p38 dependent pathways in normoxic but not hypoxic arteries. Additionally, Myosin Light Chain Kinase (MLCK) and Smooth Muscle Alpha Actin (SMαA) colocalization data shows that ET-1 promotes contractile dedifferentiation in normoxic but not hypoxic MCAs in a PKC, CaMKII, and p38 dependent manner. These results support the notion that chronic hypoxia has long term effects mediated by altered receptor expression levels and intracellular coupling. A better understanding of how chronic hypoxia affects ET-1- induced intracellular coupling will help identify potential targets for future therapies to prevent and potentially treat remodeling of cerebral arteries in infants exposed to intrauterine hypoxia

The relationship between pro-inflammatory cytokines, prostaglandins, and fetal hypothalamic-pituitary-adrenal axis activation in mares with infective pre-term delivery

Ascending placentitis is a significant cause of abortions, stillbirths, and perinatal loss in horses. A technique for laparoscopic-guided catheterization of the allantoic space was developed and utilized in an experimental model of streptococcal infective pre-term delivery in pony mares. Mares received either 1 x 107 CFU live S. zooepidemicus (n=3), 5.1 x 108 CFU live S. zooepidemicus (n=1), 1 x 107 heat-killed S. zooepidemicus (n=3), 1 mL sterile PBS (n=3). Sham control mares did not receive a transcervical inoculation (n=3). One mare not instrumented with an allantoic catheter received 5.1 x 108 CFU live S. zooepidemicus. Mares with spontaneous abortion had significantly increased CTUP compared to mares in which delivery was induced. There was not a significant effect of infection within the allantoic space on CTUP. Intrauterine infection increased the expression of IL-1â, IL-18, IL-15, and IFN-ã in a site-dependant manner. Spontaneous abortion also increased the expression of IL-1â, IL-18, IFN-ã, and iNOS in a site dependant manner. Soluble TNF-á was detected in only a few samples of fetal fluids. The concentrations of PGE2 and PGF2á in fetal fluids were increased within 24 h of delivery in mares with spontaneous abortion or intrauterine infection. Increased cortisol concentrations were observed in fetal fluid in some mares with infection or with histologic inflammation of the chorioallantois. None of the fetal fluids from mares induced to deliver or without inflammation of the chorioallantois had increased cortisol concentrations. This data suggests that the equine fetal adrenal gland less than 295 d may be capable of response to stimuli. Based on these findings, the following sequence of events leading from intrauterine infection to infective pre-term delivery is proposed. Following infection of the chorioallantois, IL-1â, IL-18, IL-15, and IFN-ã are upregulated in a site-dependant manner. IL-1â causes increased PGHS-2 (COX-2) expression, resulting in increased PGE2 and PGF2á production, and ultimately labor. IL-1â may also accelerate fetal hypothalamic-pituitary-adrenal axis (HPAA) activation, thereby promoting precocious in utero fetal maturation. The eventual outcome of pre-term labor, i.e., neonatal survivability, will depend on the degree of HPAA activation at the onset of labor