Preeclampsia In Rat Research Articles

Silencing of Fli1 Gene Mimics Effects of Preeclampsia and Induces Collagen Synthesis in Human Umbilical Arteries.

Previously we demonstrated that in patients with preeclampsia elevated levels of endogenous Na/K-ATPase inhibitor, marinobufagenin, cause inhibition of Friend leukemia virus integration 1 (Fli1), a negative regulator of collagen-1 synthesis. We hypothesized that in vitro silencing of Fli1 in healthy human umbilical arteries would be associated with an increase in collagen-1 output, similar to the effect of preeclampsia in rat and human tissues. The isolated segments of healthy human umbilical arteries were tested for sensitivity to MBG and Fli1 silencing with Fli1 siRNA or control siRNA. Following 24-hour incubation of arteries with nanomolar concentrations of marinobufagenin, Fli1 expression was inhibited 5-fold (P < 0.001), and synthesis of collagen-1 increased 3 times (P < 0.01). Twenty-four-hour incubation of umbilical artery fragments with Fli1 siRNA caused a dramatic decrease of Fli1 (7-fold; P < 0.001) and cytoplasmic PKC δ (4-fold; P < 0.001) expression in comparison to control siRNA or untreated control, followed by elevation in procollagen (3-fold; P < 0.001) and collagen-1 (3-fold; P < 0.001) levels in vascular tissue. Our results show that after silencing the Fli1 gene in healthy human umbilical arteries a new phenotype emerges which is typical for preeclampsia and is associated with vascular fibrosis.

9 Microarray analysis revealed aorta remodeling during experimental preeclampsia in rat

Introduction Normal pregnancy requires adaptations of the maternal vasculature to ensure healthy fetal and placental development. During preeclampsia these adjustments are not well established, resulting in maternal hypertension and proteinuria. The effects of preeclampsia on the maternal vasculature are not yet fully understood. Objectives Compare vascular gene expression pattern during experimental preeclampsia in the rat with healthy pregnant rats using aortic tissue. Methods We used our previously established model for preeclampsia. Pregnant Wistar outbred rats were infused with low-dose lipopolysaccharide at day 14 of pregnancy to induce experimental preeclampsia (ExpPE) ( n = 5). Control pregnant rats were infused with saline ( n = 5) at the same gestational day. At day 20 of pregnancy, the animals were sacrificed and abdominal aortas were isolated. Total aortic RNA was isolated with TRIzol reagent (Invitrogen) and gene expression was measured by GeneChip Rat Gene 1.1 ST arrays (Affymetrix, Santa Clara CA). Gene Set Enrichment Analysis (GSEA) was performed to compare the two groups. Results 526 Genes were significantly ( p -value 1.4 or p -value q -value Conclusions Our data showed that experimental preeclampsia in rats resulted in changes in gene expression levels in the aorta compared to healthy pregnant rats. The data suggest that potassium channels and neuronal innervation in the aorta may play a role in the pathophysiology of experimental preeclampsia. If these changes are also present in preeclamptic women needs to be further investigated.

Abstract 049: Preeclampsia in the Dahl Salt Sensitive Rat is Associated with Increased Uterine Artery Resistance and Reduced Placental Microvascular Density

We showed that the Dahl salt sensitive (Dahl S) rat is a spontaneous model of preeclampsia superimposed on chronic kidney disease and hypertension. This model exhibits intrauterine growth restriction, decreased pup weight, increased fetal death, and placental hypoxia; however, the underlying mechanisms are unknown. We hypothesized that a pathological remodeling and rarefaction in the maternal placental bed drives the development of preeclampsia in this model. Pregnant Dahl S and Sprague-Dawley (SD) rats were used in this study. Uterine artery resistance index (UARI) was calculated via Doppler ultrasound (Vevo 770) on day 18 of pregnancy (UARI=(peak systolic flow velocity - end diastolic flow velocity)/ peak systolic flow velocity). On day 20 of pregnancy, placentas were perfused through the uterine circulation with a silicon-polymer contrast (Microfil MV122). Individual placentas were then excised, scanned using a micro-CT scanner (SkyScan 1076), and 3D reconstructed for analysis and quantification of the placental vasculature on the maternal side. Microvascular density was calculated for vessels of diameters in the 0-500 μm ranges. UARI was higher in the Dahl S compared to the SD (0.71±0.02 vs 0.51±0.02, n=4-12, p&lt;0.05). Density of placental microvessels in the 200-500 μm range was significantly decreased in placentas from Dahl S rats, and we observed a strong trend towards a decrease in density of microvessels in the 0-200 μm range (n=3-5, Figure). These results suggest that the impaired fetal growth and placental hypoxia in the Dahl S rat may be mediated by insufficient placental vascularization and reduced blood flow to the feto-placental unit.

The immunology of pre-eclampsia

Pregnancy is a pro-inflammatory condition, characterized by phenotypical monocyte activation, and changes in monocyte function (i.e. cytokineproduction). Duringpreeclampsia,monocytes are even furtheractivatedand further changes in functionareobserved. The pro-inflammatory condition of pregnancy and preeclampsia is further supported by our data showing that during pregnancy the percentage of non-classical monocytes is increased compared with non-pregnant individuals and even further increased during preeclampsia. Pregnancy-induced monocyte activation is thought tobedue to factorsproducedby thehealthyplacenta. Inpreeclampsia, production of these factors may increase, while also other pro-inflammatory factors may be produced. The question arises whether the non-classical monocyte subset may play a role in the pathophysiology of preeclampsia. To be able to answer this question we use rat models. Similar to human pregnancy, during rat pregnancy, monocytes are activated and increased numbers of non-classical monocytes are found. During experimental preeclampsia in the rat, further activation of monocytes was found and non-classical monocytes were further increased as compared with healthy pregnant rats. Activation of monocytes, especially non-classical monocytes, may play a role in the pathophysiology of preeclampsia. It may be suggested that factors produced by the stressed placenta during preeclampsia, may activate and mature monocytes (and other immune cells), which in turn are involved in inducing preeclampsia.

Treatment of Lipoxin A4 and its analogue on low-dose endotoxin induced preeclampsia in rat and possible mechanisms

Preeclampsia (PE) is known to represent an exaggerated maternal inflammatory response to pregnancy. Lipoxin A4 (LXA4), considered as an endogenous stop signal in inflammation, has been extensively studied pre clinically for its inflammatory pro-resolving effects. Thus, in the current study, we tested the effect of BML-111 (synthetic analogue of LXA4) on experimental PE rats induced by low-dose endotoxin (LPS) and of LXA4 on human extravillous trophoblast cell line (TEV-1). In vivo experiment results showed that systolic blood pressure, 24h-urinary albumin excretion, serum TNF-α and IL-8 levels and morphologic damage of placenta and kidney caused by LPS were all effectively alleviated by BML-111. LXA4 also inhibited LPS-triggered apoptosis, activation of NF-κB, TNF-α and IL-8 mRNA and protein expression in TEV-1 cells. At the same time, BML-111 protected the cells from LPS-reduced proliferation. The current study demonstrated for the first time that LXA4 could alleviate the symptoms of PE in endotoxin exposed rats.