Search

Research Question: Sphingosine-1-phosphate (S1P) is an essential and bioactive sphingolipid with various functions, which acts through five different G-protein-coupled receptors (S1PR1-5). What is the localization of S1PR1-S1PR3 in the human placenta and what is the effect of different flow rates, various oxygen concentrations and platelet-derived factors on the expression profile of S1PR in trophoblasts?, Design: Expression dynamics of placental S1PR1-S1PR3 were determined in human first trimester (n = 10), pre-term (n = 9) and term (n = 10) cases. Furthermore, the study investigated the expression of these receptors in different primary cell types isolated from human placenta, verified the findings with publicly available single-cell RNA-Seq data from first trimester and immunostaining of human first trimester and term placentas. The study also tested whether the placental S1PR subtypes are dysregulated in differentiated BeWo cells under different flow rates, different oxygen concentrations or in the presence of platelet-derived factors., Results: Quantitative polymerase chain reaction revealed that S1PR2 is the predominant placental S1PR in the first trimester and reduces towards term (P < 0.0001). S1PR1 and S1PR3 increased from first trimester towards term (P < 0.0001). S1PR1 was localized in endothelial cells, whereas S1PR2 and S1PR3 were predominantly found in villous trophoblasts. Furthermore, S1PR2 was found to be significantly down-regulated in BeWo cells when co-incubated with platelet-derived factors (P = 0.0055)., Conclusion: This study suggests that the placental S1PR repertoire is differentially expressed across gestation. S1PR2 expression in villous trophoblasts is negatively influenced by platelet-derived factors, which could contribute to down-regulation of placental S1PR2 over time of gestation as platelet presence and activation in the intervillous space increases from the middle of the first trimester onwards., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Women with preexisting or gestational diabetes mellitus have an increased risk for developing preeclampsia. Diabetes and pregnancy are both characterized by very high prorenin levels and renin-angiotensin system activation. Prorenin bound to the (pro)renin receptor has enzymatic activity. We hypothesized that soluble (pro)renin receptor levels are elevated in high-risk pregnancies. Third trimester maternal blood samples from complicated pregnancies (n = 165), (preeclampsia [n = 76], diabetes mellitus [type I diabetes, n = 35; type II diabetes, n = 11; gestational diabetes mellitus, n = 43]), and healthy pregnancies (n = 49) were analyzed for prorenin, renin, and soluble (pro)renin receptor. There were no significant differences in prorenin or renin levels between the study groups in a multivariate model. In the group of women with gestational diabetes, soluble (pro)renin receptor concentrations were significantly higher compared with healthy pregnancies or preeclampsia. Soluble (pro)renin receptor did not correlate with renin or prorenin levels for any of the study groups. Our results show that soluble (pro)renin receptor is dysregulated in pregnancies affected by diabetes mellitus, but not in preeclampsia. Alterations in circulating soluble (pro)renin receptor are unrelated to renin/prorenin in pregnancy, but may be of pathophysiological relevance in diabetic pregnancies in a renin-angiotensin system-independent manner., (Copyright © 2017 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)

Maternal vitamin D deficiency is proposed as a risk factor for preeclampsia in humans. We tested the hypothesis that vitamin D depletion aggravates and high supplementation ameliorates the preeclampsia phenotype in an established transgenic rat model of human renin-angiotensin system-mediated preeclampsia. Adult rat dams, transgenic for human angiotensinogen (hAGT) and mated with male rats transgenic for human renin (hREN), were fed either vitamin D-depleted chow (VDd) or enriched chow (VDh) 2 weeks before mating and during pregnancy. Mean blood pressure was recorded by tail-cuff, and 24-hour urine samples were collected in metabolic cages at days 6 and 18 of gestation. Rats were sacrificed at day 21 of gestation. Depleted dams (VDd) had negligible serum 25-hydroxyvitamin D2+3 levels (mean ± SEM; 2.95 ± 0.45 nmol/l vs. VDh 26.20 ± 2.88 nmol/l, P = .01), but in both groups, levels of 1,25(OH)2D3 remained below detection level of 25 pmol/l. Dietary vitamin D depletion did not aggravate hypertension (mean ± SEM BP, day 20 of gestation: 151.38 ± 5.65 mmHg VDd vs. 152.00 ± 4.10 mmHg VDh) or proteinuria. Fetal anthropometrics were similar between the groups, whereas VDd displayed lower placental:fetal weight ratios (0.15 vs. 0.16 g/g, P = .01) and increased sFlt-1/PlGF ratio. Expression of hREN was lower in placenta of VDd dams (0.82 ± 0.44 AU vs. 1.52 ± 0.15 AU, P = .04). Expression of key vitamin D metabolizing enzymes was unchanged. Dietary vitamin D intervention did not alter key aspects of the preeclampsia phenotype using the transgenic rodent model of human renin-angiotensin system-mediated pre-eclampsia, plausibly due to altered vitamin D metabolism or excretion in the transgenic rats., (Copyright © 2016 American Society of Hypertension. Published by Elsevier Inc. All rights reserved.)

The mechanisms of deficient placentation in the first trimester remain poorly understood, although apoptosis, hypoxia, and oxidative stress have been implicated. High uterine artery Doppler resistance indexes (RIs) are predictive of placental complications of pregnancy, such as preeclampsia, fetal growth restriction, and stillbirth. We provide evidence that even in the first trimester, pregnancies with high uterine artery Doppler RI demonstrate alterations in placental gene and protein expression. Apoptosis was significantly higher in high RI placental tissue, as determined by Western blot analysis of cleaved poly (ADP-ribose) polymerase and caspase 3. Protein expression of the trophoblast survival factor insulin-like growth factor-2 was significantly lower. Both high and normal RI placentas showed evidence of hypoxia and oxidative stress with expression of hypoxia-inducible factors 1α and 2α, heat shock protein 70, presence of nitrotyrosine residues, and lipid peroxidation. We observed no exaggerated placental hypoxia or oxidative stress associated with high RI pregnancies. High RI placental tissue demonstrated an altered balance of antioxidant enzyme activity. Hypoxia and oxidative stress appear to be a physiological state in early pregnancy; our data did not support the hypothesis that they are associated with deficient placentation in the first trimester. Higher levels of apoptosis, reduced insulin-like growth factor-2 expression, and altered antioxidant defenses may contribute to abnormal placentation and the later development of pregnancy complications, such as preeclampsia, fetal growth restriction, and stillbirth., (Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

The pathogenesis of preeclampsia (PE) includes the release of placental factors into the maternal circulation, inducing an inflammatory environment in the mother. One of the factors may be the proinflammatory chemokine fractalkine, which is expressed in the syncytiotrophoblast of human placenta, from where it is released into the maternal circulation by constitutive shedding. We examined whether placental fractalkine is up-regulated in severe early-onset PE and whether the proinflammatory cytokines tumor necrosis factor (TNF)-α and IL-6 are able to increase the expression of fractalkine. Gene expression analysis, enzyme-linked immunosorbent assay, and immunohistochemistry consistently showed increased fractalkine expression in placentas from severe early-onset PE, compared to gestational age-matched controls. Expression of a disintegrin and metalloproteinases (ADAMs) 10 and 17, which convert transmembrane fractalkine into the soluble form, was significantly increased in these cases. Incubation of first-trimester placental explants with TNF-α provoked a significant increase in fractalkine expression and release of the soluble form, whereas IL-6 had no effect. TNF-α-mediated up-regulation of placental fractalkine was reversed in the presence of the aspirin-derivative salicylate, which impaired activation of NF-κB p65 in TNF-α-treated explants. On the basis of data from placental explants, we suggest that increased maternal TNF-α may up-regulate the expression and release of placental fractalkine, which, in turn, may contribute to an exaggerated systemic inflammatory response in PE., (Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Introduction: Vitamin D may ameliorate hypertension and kidney disease through genomic and extra-genomic pathways., Objective: To investigate the impact of vitamin D in a transgenic rat model of angiotensin II-mediated hypertensive organ failure., Methods: In 4-week-old age-matched rats overexpressing the human renin and angiotensinogen genes, group 1 (n=18) received vitamin D depleted chow; group 2 (n=15) standard chow and intraperitoneal paricalcitol at 800ng/kg thrice weekly; and group 3 (n=15) standard chow and vehicle injections. Blood pressure (tail cuff) and 24-h albuminuria were determined once weekly. After three weeks, animals were sacrificed. Heart tissue was examined for atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) by RT-PCR., Results: The vitamin D depleted group had higher blood pressure at week 1 (mean difference 23.4mmHg, 95% CI 9.1-37.7) and tended to have higher blood pressure in weeks 2 and 3 (mean difference 14.3mmHg 95% CI -0.02-28.7 and 15.2mmHg 95% CI -1.5-33). The depletion group had higher heart-to-body weight ratio, and a trend towards higher ANP and BNP levels. The group receiving paricalcitol did not perform better. No differences were found between groups in mortality or proteinuria., Conclusion: Short-term vitamin D depletion aggravated hypertension and end-organ damage in a rat model of angiotensin II-induced hypertension. Short-term interventions with high-dose vitamin D analogues had no protective effect., (Copyright © 2013. Published by Elsevier B.V.)

Introduction: miRNAs are small ∼22nt RNAs, important in the fine-tuning of mRNA in many organs including placenta. Preeclampsia (PE) is a heterogenous disease which may be divided into early-onset PE, which is a more severe form with assumed placental origin, and late-onset PE, with assumed maternal origin., Objectives: The aim of this study was to investigate the differential expression of miRNAs in early and late-onset PE compared to controls using high throughput sequencing., Methods: Placentas were obtained from an ongoing biobank collection at Oslo University Hospital. 23 normotensive controls, 23 early-onset PE (delivery at gestational week <34) and 26 late-onset PE (week⩾34) samples were sequenced using Illumina sequencing technology. Differential expressed miRNAs were identified by the EdgeR package in R and predicted targets were estimated by miRWalk., Results: 3 placental miRNAs were differentially expressed between controls and late-onset PE, 4 miRNAs were differentially expressed between early- and late-onset PE and 51 miRNAs were differentially expressed between early-onset PE and controls. Combining with mRNA array data from a subgroup of the same patients, we identified predicted targets of some of these miRNAs with significant inverse correlation between the respective mRNAs/miRNAs., Conclusion: These preliminary results suggest that miRNAs in placenta could be more important in the dysregulation of mRNAs in early-onset PE than in late-onset of the disease., (Copyright © 2013. Published by Elsevier B.V.)

Objective: To explore biomarkers indicating cardiovascular disease in pregnant women with diabetes or preeclampsia, since these women are at increased risk for future cardiovascular disease., Study Design: EDTA-plasma from 262 women in gestational week 24-42 (healthy pregnancies n=71, preeclampsia n=105, type 2 diabetes n=17, gestational diabetes n=61, diabetes with preeclampsia n=8) was analyzed by immunoassay for neopterin, midregional pro-adrenomedullin (MR-proADM) and C-terminal pro-arginine vasopressin (CT-proAVP). The diabetes groups were also analyzed for midregional pro-atrial natriuretic peptide (MR-proANP), and compared to previously reported MR-proANP concentrations for healthy, normotensive and preeclamptic patients., Results: In contrast to preeclampsia, median plasma MR-proANP was not increased in pregnancies complicated by diabetes, but in fact lower, compared to healthy pregnancies. Neopterin was increased in diabetic pregnancies and in late onset preeclampsia, compared to healthy pregnancies. Median plasma MR-proADM was increased in pregnancies complicated by gestational diabetes or preeclampsia, compared to healthy pregnancies. Median plasma MR-proANP was increased in diabetic pregnancies complicated by preeclampsia compared to pregnant women with diabetes only., Conclusion: Women with pregnancies complicated by diabetes mellitus or preeclampsia are at risk for future cardiovascular disease, but differ in circulating cardiovascular biomarker profile. A cardiovascular biomarker profiling during pregnancy might prove helpful in identifying women at risk for future cardiovascular disease, thus enabling targeted prophylactic interventions and follow-up., (Copyright © 2012 International Society for the Study of Hypertension in Pregnancy. Published by Elsevier B.V. All rights reserved.)