Endogenous lysophosphatidic acid participates in vascularisation and decidualisation at the maternal-fetal interface in the rat.

Lysophosphatidic acid (LPA) affects several female reproductive functions through G-protein-coupled receptors. LPA contributes to embryo implantation via the lysophospholipid LPA3 receptor. In the present study we investigated the participation of endogenous LPA signalling through the LPA3 receptor in vascularisation and decidualisation, two crucial events at the maternal-fetal interface. Pregnant rats were treated with diacylglycerol pyrophosphate (DGPP), a highly selective antagonist of LPA3 receptors, on Day 5 of gestation. Pregnant rats received intrauterine (i.u.) injections of single doses of DGPP (0.1mgkg-1) in a total volume of 2µL in the left horn (treated horn) in the morning of GD5. DGPP treatment produced aberrant embryo spacing and increased embryo resorption. The LPA3 receptor antagonist decreased the cross-sectional length of the uterine and arcuate arteries and induced histological anomalies in the decidua and placentas. Marked haemorrhagic processes, infiltration of immune cells and tissue disorganisation were observed in decidual and placental tissues from sites of resorption. The mRNA expression of three vascularisation markers, namely interleukin 10 (Il10), vascular endothelial growth factor (Vegfa) and vascular endothelial growth factor receptor 1 (Vegfr1), was reduced at sites of resorption from Day 8. The results show that the disruption of endogenous LPA signalling by blocking the LPA3 receptor modified the development of uterine vessels with consequences in the formation of the decidua and placenta and in the growth of embryos.

Defective trophoblast invasion underlies fetal growth restriction and preeclampsia-like symptoms in the stroke-prone spontaneously hypertensive rat.

STUDY QUESTION: What is the impact of chronic hypertension on placental development, fetal growth and maternal outcome in the stroke-prone spontaneously hypertensive rat (SHRSP)? SUMMARY ANSWER: SHRSP showed an impaired remodeling of the spiral arteries and abnormal pattern of trophoblast invasion during placentation, which were associated with subsequent maternal glomerular injury and increased baseline hypertension as well as placental insufficiency and asymmetric fetal growth restriction (FGR). WHAT IS KNOWN ALREADY: A hallmark in the pathogenesis of preeclampsia (PE) is abnormal placentation with defective remodeling of the spiral arteries preceding the onset of the maternal syndrome. Pregnancies affected by chronic hypertension display an increased risk for PE, often associated with poor maternal and fetal outcomes. However, the impact of chronic hypertension on the placentation process as well as the nature of the factors promoting the development of PE in pregnant hypertensive women remain elusive. STUDY DESIGN, SIZE, DURATION: Timed pregnancies [n = 5] were established by mating 10-12-week-old SHRSP and Wistar Kyoto (WKY, normotensive controls) females with congenic males. Maternal systolic blood pressures (SBPs) were recorded pre-mating, throughout pregnancy (GD1-19) and post-partum by the tail-cuff method. On selected dates, 24 h urine- and blood samples were collected, and animals were euthanized for isolation of implantation sites and kidneys for morphometrical analyses. PARTICIPANTS/MATERIALS, SETTING, METHODS: The 24 h proteinuria and the albumin:creatinine ratio were used for evaluation of maternal renal function. Renal injury was assessed on periodic acid Schiff, Masson's trichrome and Sirius red stainings. Placental and fetal weights were recorded on gestation day (GD)18 and GD20, followed by determination of fetal cephalization indexes and developmental stage, according to the Witschi scale. Morphometric analyses of placental development were conducted on hematoxylin-eosin stained tissue sections collected on GD14 and GD18, and complemented with immunohistochemical evaluation of isolectin B4 binding for assessment of placental vascularization. Analyses of vascular wall alpha actin content, perforin-positive natural killer (NK) cells and cytokeratin expression by immunohistochemistry were used for evaluation of spiral artery remodeling and trophoblast invasion. MAIN RESULTS AND THE ROLE OF CHANCE: SHRSP females presented significantly increased SBP records from GD13 to GD17 (SBPGD13 = 183.9 ± 3.9 mmHg, P < 0.005 versus baseline) and increased proteinuria at GD18 (P < 0.01 versus WKY). Histological examination of GD18 kidneys revealed glomerular enlargement and mesangial matrix expansion, which were not evident in pregnant WKY or age-matched virgin SHRSP. At GD20, SHRSP displayed a significant reduction of placental mass (P < 0.01 versus WKY) and signs of placental insufficiency (i.e. hypertrophy and reduced branching morphogenesis of the labyrinth layer), associated with decreased offspring weights and increased cephalization index (both P < 0.001 versus WKY) indicating asymmetric FGR. Notably, SHRSP placentas displayed an incomplete remodeling of spiral arteries starting as early as GD14, with luminal narrowing and reduced densities of perivascular NK cells followed by decreased infiltration of endovascular trophoblasts at GD18. LARGE SCALE DATA: n/a. LIMITATIONS, REASONS FOR CAUTION: A pitfall of the present study is the differences in the blood pressure profiles between rats and humans (i.e. unlike pregnancies affected by PE, blood pressure in SHRSP and other hypertensive rat models decreases pre-delivery), which limits extrapolation of the results. WIDER IMPLICATIONS OF THE FINDINGS: Our findings provide new insights on the role of chronic hypertension as a risk factor for PE by interfering with early events during the placentation process. The SHRSP strain represents an attractive model for further studies aimed at addressing the relative contribution of intrinsic (i.e. placental) and extrinsic (i.e. decidual/vascular) factors to defective spiral artery remodeling in pregnancies affected by PE. STUDY FUNDING AND COMPETING INTEREST(S): This work was supported by research grants from Fundación Florencio Fiorini to G.B., from Charité Stiftung to S.M.B. and University of Buenos Aires (UBACyt) to J.T. The authors have no competing interests to declare.

[Increase S/D ratio in uterine artery as a predictor for preeclampsia in adolescent patients]. / Aumento del índice S/D en la arteria uterina como predictor de preeclampsia en adolescentes.

BACKGROUND: Pregnancy during adolescence has been rising in the past years, and it is well known that preeclampsia affects teenagers, because maternal age and primigravida are risk factors. There are different ways and methods to predict preeclampsia, for example doppler velocimetry. OBJECTIVE: Determine S/D ratio of uterine artery in pregnant teenagers between 24-28 weeks and correlation with preeclampsia. MATERIAL AND METHOD: Observational study in 50 pregnant teenagers (14-19 years) obtaining uterine artery waveform at 24-28 weeks gestation recording S/D ratio. RESULTS: Sensitivity and specificity of 90% with a positive predictive value of 69.23% and negative predictive value of 97.3%. 13 patients had S/D ratio greater than 2.6, of which 5 had gestational hypertension, 3 with preeclampsia, 1 with Fetal Growth Restriction, 4 with normal pregnancy. Relative Risk was 25.62 (3.58-183.13) with odds ratio of 81.00 (6.83-2260.88) and p value 0.00002. CONCLUSION: analysis of uterine artery flow velocity waveforms is a method to predict preeclampsia.

Immunohistochemical demonstration of blood vessels alpha-actin down-regulation in LPS-treated pregnant mice.

Lipopolysaccharide (LPS), produced by gram-negative bacteria, mediates vasodilatation, changing the action of contractile smooth muscle by increasing expression of nitric oxide synthase and prostaglandin. For the first time we demonstrate, by immunohistochemical methods, that administration of LPS to pregnant mice causes alpha-actin-mediated down-regulation of contractile filaments in uterine blood vessels, thereby potentially increasing vessels permeability, blood supply, and immune cells homing to this environment, culminating in the reestablishment of uterine homeostasis.