sFlt-1 Research Articles

Impaired Endothelium-Dependent Vasodilation and Increased Levels of Soluble Fms-like Tyrosine Kinase-1 Induced by Reduced Uterine Perfusion Pressure in Pregnant Rats: Evidence of Protective Effects with Sodium Nitrite Treatment in Preeclampsia.

Preeclampsia (PE) is a hypertensive disorder of pregnancy and is associated with increases in soluble fms-like tyrosine kinase-1 (sFlt-1) and reductions in nitric oxide (NO) levels. Placental ischemia and hypoxia are hypothesized as initial pathophysiological events of PE. Nitrite (NO metabolite) may be recycled back to NO in ischemic and hypoxic tissues. Therefore, this study examined the sodium nitrite effects in an experimental model of PE. Pregnant rats received saline (Preg group) or sodium nitrite (Preg + Na-Nitrite group). Pregnant rats submitted to the placental ischemia received saline (RUPP group) or sodium nitrite (RUPP + Na-Nitrite group). Blood pressure, placental and fetal weights, and the number of pups were recorded. Plasma levels of NO metabolites and sFlt-1 were also determined. Vascular and endothelial functions were also measured. Blood pressure, placental and fetal weights, the number of pups, NO metabolites, sFlt-1 levels, vascular contraction, and endothelium-dependent vasodilation in the RUPP + Na-Nitrite rats were brought to levels comparable to those in Preg rats. In conclusion, sodium nitrite may counteract the reductions in NO and increases in sFlt-1 levels induced by the placental ischemia model of PE, thus suggesting that increased blood pressure and vascular and endothelial dysfunctions may be attenuated by sodium nitrite-derived NO.

Maternal Thyroid Function and Biochemical Markers of Placental Function in Early Pregnancy.

A link between maternal thyroid function and the placental biomarkers, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), has been brought forward. This study aimed to describe their association in early pregnancy. Retrospective cohort study. Eight hundred and fifty-eight pregnant women from the North Denmark Region, 2013, with blood samples drawn in early pregnancy. Thyroid-stimulating hormone (TSH), free thyroxine (fT4), thyroid-peroxidase antibodies (TPO-Ab), thyroglobulin antibodies (Tg-Ab) (ADVIA Centaur XPT, Siemens Healthineers), sFlt-1 and PlGF (Kryptor Compact, ThermoFisher Scientific) were measured. The association between maternal TSH and fT4 and percentile (pc) levels of sFlt-1 and PlGF (< 25th pc, 25-75th pc, > 75th pc) was evaluated using regression analysis and reported as adjusted beta coefficient (aβ). The frequency of maternal thyroid autoantibodies (TPO-Ab > 60 U/mL or Tg-Ab > 33 U/mL) by pc levels of sFlt-1 and PlGF was compared using chi-squared test. Higher levels (> 75th pc) of sFlt-1 associated with lower TSH (aβ 0.62, 95% CI: 0.51-0.76) and higher fT4 (aβ 1.03, 95% CI: 1.01-1.05). Higher levels of PlGF associated with lower TSH (aβ 0.82, 95% CI: 0.69-0.98), but not with levels of fT4 (aβ 1.00, 95% CI: 0.97-1.02). No association with maternal thyroid autoantibodies was found (TPO-Ab: sFlt-1: p-value 0.5 and PlGF: p-value 0.1; Tg-Ab: sFlt-1: p-value 0.7 and PlGF: p-value 0.1). In a large cohort of Danish pregnant women, higher levels of sFlt-1 and PlGF associated with maternal thyroid function in early pregnancy, while there was no association with maternal thyroid autoantibodies.

A-311 Evaluating the Predictive Value of the sFlt-1/PlGF Ratio in Hypertensive Pregnancies for Preeclampsia

Abstract Background Preeclampsia (PE) is a hypertensive pregnancy disorder affecting around 5% of all pregnancies, and it continues to be a leading cause of maternal and neonatal morbidity and mortality in the United States. The incidence of hypertensive pregnancies is on the rise, attributed to the increasing prevalence of obesity and chronic hypertension. The development of a straightforward diagnostic test to accurately differentiate PE from gestational or chronic hypertension is crucial to avoid unnecessary hospitalizations. Despite the ongoing development of prediction models for PE, conventional clinical and laboratory measures have not been effective in predicting disease progression. Recent research has focused on the ratio of two serum biomarkers: soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), particularly in patients with a clinical suspicion of PE in acute settings. These studies have shown promise, with many indicating that the sFlt-1/PlGF ratio can effectively predict the presence or absence of PE. This study was conducted to assess the predictive value of the sFlt-1/PlGF ratio in pregnancies complicated by hypertension, aiming to contribute to the early detection and management of PE. Methods Pregnant individuals with hypertensive disorders at or above the age of 18 receiving prenatal care at NewYork-Presbysterian-Weill Cornell Hospital were enrolled in this study. We measured the levels of sFlt-1 and PlGF using fully automated Elecsys immunoassays (Roche Diagnostics). Subsequently, a prospective analysis of the serum sFlt-1/PlGF ratio was performed. A receiver operating characteristic (ROC) curve was used to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the ratio in predicting PE. To assess the prognostic accuracy of the sFlt-1/PlGF ratio, patients were randomly assigned to a development and a validation cohort at a ratio of 30:70. Results We collected a total of 137 serum samples of hypertensive pregnancies, with all ≥20 weeks of gestational age (GA). Of these, 47 (34.3%) developed PE within 2 weeks. The samples were divided into two cohorts: 98 were included in the development cohort, and 39 in the validation cohort. Within these groups, 34 (34.7%) of the development cohort and 13 (33.3%) of the validation cohort developed PE within 2 weeks, respectively. In the development cohort, the median sFlt-1/PlGF ratio was 85 (Interquartile range, [IQR], 44-164) among pregnant women who developed PE within 2 weeks. This was significantly higher compared to a median ratio of 8 (IQR, 3-35) observed in those who did not develop PE (p&amp;lt;0.001). The area under the ROC curve was 0.87, indicating good discriminative ability. An optimized cutoff ratio of 38 was determined, based on the max of combined sensitivity and specificity. When applied into the validation cohort, this cutoff yields a 90% (95% confidence interval [CI], 70-97) NPV and 58% (95%CI, 37-76) PPV with an 85% sensitivity (95%CI, 58-96) and a 69% specificity (95%CI, 50-83). Conclusions In women with a hypertensive disorder of pregnancy presenting GA≥20 weeks of gestation, the measurement of serum sFlt-1/PlGF ratio demonstrated clinical value in predicting the development of PE.

A-313 Use of the Preeclampsia Ratio in the Prognosis of Preterm Delivery and Adverse Outcomes

Abstract Background Preeclampsia (PE) is a hypertensive disorder of pregnancy that is characterized by high blood pressure and end-organ dysfunction with or without proteinuria after 20 weeks gestation. PE occurs in 6-8% of pregnancies and contributes to significant fetal, neonatal, and maternal morbidity and mortality. The ratio of two angiogenic placental proteins, soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF), are used in the management of PE. The purpose of this study was to evaluate use of the sFlt-1/PlGF ratio (PE ratio) generated using the ADVIA Centaur® and Atellica® IM sFlt-1 assay and the ADVIA Centaur and Atellica IM PlGF assays in the prognosis of preterm delivery and adverse outcomes in women presenting with signs and symptoms of PE. Methods A total of 654 females with singleton pregnancies between gestational weeks 20+0 days and 35+6 days and who had signs and symptoms of PE, but without severe features of PE were enrolled at 24 collection sites and followed prospectively for two weeks. Serum samples were collected at enrollment and adverse outcomes that included preterm delivery were prospectively collected within the two weeks after enrollment. Serum samples from approximately half of the population (n=316) were tested in singlicate using the sFlt-1 and PlGF assays on the ADVIA Centaur system in a derivation study that determined the optimal cutoff of the PE ratio in relation to adverse outcome. The remaining serum samples (n=338) were subsequently tested on the ADVIA Centaur system in a cut-off validation study that evaluated the clinical performance (sensitivity [SE], specificity [SP], positive predictive value [PPV], negative predictive value [NPV]) of the PE ratio at the derived cutoff in relation to adverse outcome. Method comparison studies were performed between the ADVIA Centaur versus the Roche Elecsys sFlt-1 and PlGF assays (n=255) and the ADVIA Centaur versus the Atellica IM sFlt-1 and PlGF assays (n=316). Results The rate of maternal adverse outcomes within two weeks was similar in the derivation study (32.3%) and validation study (28.1%). Using a receiver operating characteristic (ROC) curve analysis with the derivation cohort, a derived cutoff of 38 showed optimal clinical performance of the PE ratio in relation to adverse outcome (SE=72.5%, SP=94.7%, PPV=84.6%, NPV=89.5%). Similar clinical performance results of the PE ratio at the cutoff of 38 in relation to adverse outcome were found with the verification cohort (SE=88.42%, SP=87.65%, PPV=73.68%, NPV=95.09%). Weighted Deming regression analysis demonstrated equivalency between the Centaur, Roche, and Atellica PE ratios with correlation coefficients (r) of 0.9242 (Centaur vs Roche) and 0.995 (Centaur vs Atellica). Conclusions Measurement of sFlt-1 and PlGF to determine PE ratio can be performed on either the ADVIA Centaur or Atellica Analyzer and can be used to identify women presenting with PE or signs and symptoms of PE who are at high risk of experiencing an adverse event in the subsequent two weeks. Not available for sale in the U.S.A. The products/features mentioned herein are not commercially available in all countries. Their future availability cannot be guaranteed.

A-308 Placental Growth Factor Kryptor Immunoassay Reveals Quality Control Imprecision and Drift

Abstract Background The utility and value of determining the soluble fms-like tyrosine kinase-1 to placental growth factor (sFlt-1/PlGF) ratio for predicting the likelihood of progression to pre-eclampsia in pregnant women admitted with hypertension are increasingly becoming widely recognized. A key finding of the multi-center PRAECIS trial (NEJM Evid 2022;1(12)) is the observation that sFlt-1/PlGF ratios ≥ 40 correlate with higher risk for adverse maternal outcomes. The sFlt-1 and PlGF immunoassays performed on the ThermoFisher Scientific B·R·A·H·M·S Kryptor autoanalyzer became the first FDA-approved tests in 2023 for determining sFlt-1/PlGF ratio. In this study, an evaluation of the analytical performance of the sFlt-1 and PlGF KRYPTOR immunoassays was performed, which included analyte measuring range (AMR), accuracy, precision, and stability studies. Methods Calibration and QC materials (consisting of lyophilized recombinant human proteins), test reagents and solutions, and consumables were purchased and provided by ThermoFisher Scientific. Analytical runs were performed according to vendor’s instructions by trained medical laboratory scientists. Between-day precision of our two instruments for both immunoassays was assessed by assaying all three levels of sFlt-1 and PlGF QC materials, as well as patient serum pools with low PlGF concentration, once to twice daily for multiple consecutive days. Results While the analytical performance of the sFlt-1 immunoassay was robust and performed according to expectation (within-day CV &amp;lt;1% and between-day CV &amp;lt;3%), the PlGF immunoassay was surprisingly less reliable. Imprecision and inaccuracy of the PlGF immunoassay at the low end of its analytical measurement range was reflected by both sporadically out-of-control between-day measurements of all three QC levels (with target ranges of 24 - 36 pg/mL, 80 - 120 pg/mL, and 320 - 480 pg/mL), as well as slow downward drifts of particularly the low level QC material. In one instance, a downtrend was observed from 28 pg/mL to 14 pg/mL over 6 days, even with fresh reagents, solutions, and calibration. Such shortened stability of the PlGF assay does not meet the vendor’s claims of calibration stability of 15 days and onboard kit stability of 29 days. Using vendor’s provided material, the AMR of both sFlt-1 and PlGF were adequately verified and showed excellent linearity (r2&amp;gt; 0.99). Conclusions Despite low level QC imprecision and drift, the sFlt-1/PlGF ratios determined using the B·R·A·H·M·S Kryptor analyzers are acceptable for clinical use but with the caveat that we will perform batch testing with bracketing QCs and conduct stringent QC monitoring, frequent calibrations, and reduce the onboard kit stability as defined by ThermoFisher Scientific. Our findings serve as a reminder that FDA approval does not preclude thorough verification studies of any assay prior to implementation for clinical use.

Placenta may exert fetal protection against maternal high salt diet intake via renin-angiotensin-aldosterone system

ObjectiveThis study investigated the effects of high compared to normal dietary salt intake on fetoplacental vascular function, activity of renin-angiotensin-aldosterone system (RAAS), placental pro- and anti-angiogenic factors and biomarkers of placental remodeling and oxidative stress during healthy uncomplicated pregnancy. Materials and MethodsBased on their 24-hour sodium excretion pregnant women (37–40 weeks’ gestation) were categorized into three groups: normal salt (NS, <5.75 g/day, N=12), high salt (HS, 5.75–10.25 g/day, N=36), and very high salt (VHS, >10.25 g/day, N=17). Pulsatility (PI) and resistive index of middle cerebral artery (MCA) and umbilical artery, plasma renin activity (PRA), serum aldosterone, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) concentrations, as well as placental vascular endothelial growth factor C (VEGF-C), oxidative/antioxidative stress markers (TBARS/FRAP) and matrix metalloproteinase 9 (MMP-9) concentration were measured. ResultsPI MCA was significantly decreased in HS/VHS groups compared to NS group. HS/VHS intake did not suppress PRA and aldosterone concentration. Serum PlGF concentration was significantly increased while sFlt-1 concentration and sFlt-1/PlGF ratio were significantly decreased in VHS group compared to NS group. MMP-9, VEGF-C concentration, TBARS and FRAP in placental tissue were similar between study groups. ConclusionsHS/VHS diet does not suppress RAAS during pregnancy; however, it is associated with decreased PI MCA, a significantly decreased sFlt-1/PlGF ratio and unchanged biomarkers of placental remodeling or oxidative stress in healthy pregnant women, suggesting the presence of a possible protective or compensatory mechanism aimed at preserving placental function and pregnancy outcome itself in terms of maternal HS intake.

Advancing diagnostics: integrating microRNA profiling and protein markers in ectopic pregnancy detection

IntroductionEctopic pregnancy (EP) poses significant health risks, particularly in developing nations, necessitating improved diagnostic methods. This study aimed to explore potential biomarkers for EP diagnosis.MethodsA case–control study was conducted at...

Can Peripheral Arterial Tonometry and Biomarkers Help Identify Women Who Will Have Progressively Worsening Hypertensive Disorders of Pregnancy?

This study aimed to (1) evaluate whether endothelial dysfunction, as measured by peripheral arterial tonometry (PAT) indices and biomarker (soluble fms-like tyrosine kinase-1 [sFLT], brain natriuretic peptide [BNP]) levels at 34 weeks gestation, can predict progression from nonsevere to severe hypertensive disorders of pregnancy (HDPs); and (2) develop a clinical risk model for prediction of progression from nonsevere to severe HDP. We prospectively enrolled patients with a singleton gestation carrying a nonsevere HDP diagnosis. Forty-five participants were enrolled for PAT evaluation and serum collection between 340/7 and 366/7 weeks. PAT indices (e.g., Augmentation Index normalized to a heart rate of 75 bpm [AI75]) and biomarker concentrations were assessed at enrollment. The primary outcome was progression from a nonsevere diagnosis in the late preterm period to a diagnosis of preeclampsia with severe features or superimposed preeclampsia. Statistical analyses included two-sample t-tests, Fisher's exact tests, and multivariate modeling. Thirteen subjects (30%) progressed to severe disease. No significant differences in mean PAT indices between the outcome groups were found. We found a significant difference in mean sFLT values between the two groups (p = 0.02, area under the curve [AUC] of 0.609), but not in mean BNP values. An endothelial dysfunction index (presence of fetal growth restriction, "high" AI75, and positive systolic blood pressure slope) discriminated between progression and nonprogression (p = 0.03, AUC of 0.707). sFLT level was a marker of progression from nonsevere to severe HDP. Further, a novel endothelial dysfunction index discriminated between progression and nonprogression to severe disease with good performance. · HDPs are important causes of morbidity and mortality.. · The sequelae of HDPs are not limited to pregnancy.. · Developing accurate tools to predict severe HDPs is of great clinical importance.. · Our index shows promising performance for predicting progression from nonsevere to severe HDPs..

Reference Intervals for the ratio of Soluble FMS-like Tyrosine Kinase-1 and Placental Growth Factor in Pregnant and Non-Pregnant Females in Pakistani Population

Reference Intervals for the ratio of Soluble FMS-like Tyrosine Kinase-1 and Placental Growth Factor in Pregnant and Non-Pregnant Females in Pakistani Population

Intermanufacturer assessment of diagnostic performance of angiogenic ratio vs glycosylated fibronectin in women with suspected pre-eclampsia.

To compare the diagnostic performance of different manufacturers' immunoassays for the soluble fms-like tyrosine kinase-1 (sFlt-1)-to-placental growth factor (PlGF) ratio with that of a point-of-care test for glycosylated fibronectin (GlyFn) in women with suspected pre-eclampsia (PE). This was a prospective, single-center, double-blinded, non-interventional study of East Asian women with a singleton pregnancy who presented with hypertension with or without clinical features of PE after 20 weeks' gestation between January 2020 and March 2022. Maternal serum samples were collected at the time of presentation, and subsequent management followed the departmental protocol, based on gestational age, severity of hypertension, fetal condition and presence of severe PE features. Women diagnosed with PE at presentation were excluded. PE was diagnosed according to the 2018 International Society for the Study of Hypertension in Pregnancy classification. Levels of sFlt-1 and PlGF were measured using the Cobas e411 (Roche Diagnostics), BRAHMS KRYPTOR (ThermoFisher Scientific) and iMAGIN 1800 (Ningbo-Aucheer) platforms. GlyFn levels were measured using the Lumella™ GlyFn PoC test (Diabetomics). The predictive performance of each test to rule out PE within 7 days and rule in PE within 28 days from the date of presentation was assessed. Based on the PROGNOSIS study, a sFlt-1/PlGF ratio of ≤ 38 on the Roche platform was used to predict the absence of PE within 7 days. The sFlt-1/PlGF ratio was classified as high or low using platform-specific thresholds equivalent to a Roche sFlt-1/PlGF ratio of 38, which were derived using Passing-Bablok regression. GlyFn was categorized as high or low using two reported clinical management thresholds (263 μg/mL and 510 μg/mL). Overall, 236 women with suspected PE were included, of whom 70 (29.7%) were diagnosed with PE; 36 (51.4%) and 70 (100%) developed PE within 7 days and 28 days, respectively. Eighty-eight (37.3%) women had a sFlt-1/PlGF ratio of > 38 on the Roche platform, 79 (33.5%) women had a sFlt-1/PlGF ratio of > 55 on the KRYPTOR platform and 96 (40.7%) women had a sFlt-1/PlGF ratio of > 40 on the iMAGIN 1800 platform. Furthermore, 62 (26.3%) and four (1.7%) women had a GlyFn level of > 263 μg/mL and > 510 μg/mL, respectively. The negative predictive value (NPV) of the sFlt-1/PlGF ratio measured on the Roche, KRYPTOR and iMAGIN 1800 platforms to rule out PE within 7 days after presentation was 83.3%, 82.0% and 82.9%, respectively, while that for GlyFn > 263 μg/mL and > 510 μg/mL was 82.6% and 70.4%, respectively. The corresponding positive predictive values (PPV) to rule in PE within 28 days after presentation were 50.5%, 52.3% and 46.7%, respectively, for the sFlt-1/PlGF ratio, and 35.4% and 50.0%, respectively, for GlyFn > 263 μg/mL and > 510 μg/mL. The predictive performance of different manufacturers' assays for the sFlt-1/PlGF ratio to rule in and rule out PE were similar once standardized to a common threshold. Our findings suggest that the sFlt-1/PlGF ratio and GlyFn using a cut-off of 263 μg/mL can both be utilized to rule out PE within 7 days after assessment, with a moderate NPV. The PPV for ruling in PE within 28 days remains poor. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Discussion on the evaluation of the therapeutic efficacy of uterine artery blood flow parameters and serum PLGF and sFlt-1 in patients with recurrent spontaneous abortion

ObjectiveTo investigate the effects of different drug treatments on uterine artery blood flow parameters, serum placental growth factor (PLGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and sFlt-1/PLGF in patients with recurrent spontaneous abortion and to explore the predictive value of uterine artery blood flow parameters, serum PLGF, sFlt-1, and sFlt-1/PLGF for pregnancy outcomes.MethodsThis retrospective cohort study included 173 patients who experienced recurrent spontaneous abortion and 100 control patients. Patients with recurrent spontaneous abortion were divided into an aspirin group (75 patients), aspirin combined with low molecular weight heparin (LMWH) group (68 patients), and non-drug group (30 patients) based on different drug treatments. Uterine artery blood flow parameters at gestational weeks 30-31+6 were monitored for the four groups, and serum samples were collected at gestational weeks 30-31+6 to measure the levels of serum PLGF and sFlt-1 and calculate the sFlt-1/PLGF ratio.Results1. Uterine artery blood flow parameters at gestational weeks 30-31+6 were significantly greater in the non-drug group than in the aspirin group, combined drug group, and control group (p<0.05). 2. Serum PLGF levels and the sFlt-1/PLGF ratio at gestational weeks 30-31+6 were significantly lower in the non-drug group than in the aspirin group, combined drug group, and control group, while serum sFlt-1 levels were significantly greater in the non-drug group than in the aspirin group, combined drug group, and control group (p<0.05). 3. Serum PLGF, sFlt-1, and sFlt-1/PLGF had lower diagnostic efficiency for predicting hypertensive disorders during pregnancy than the combined diagnostic efficiency of serum PLGF, sFlt-1, and sFlt-1/PLGF with uterine artery blood flow parameters at gestational weeks 30-31+6.ConclusionAspirin and aspirin combined with LMWH can upregulate serum PLGF and decrease serum sFlt-1 levels in patients with recurrent spontaneous abortion, reduce the miscarriage rate, and significantly improve pregnancy outcomes. The combination of serum PLGF, sFlt-1, sFlt-1/PLGF, and uterine artery blood flow parameters can effectively predict hypertensive disorders during pregnancy.

Prediction of adverse maternal and perinatal outcomes associated with pre-eclampsia and hypertensive disorders of pregnancy: a systematic review and meta-analysis

Hypertensive disorders of pregnancy are a leading cause of maternal and perinatal morbidity and mortality. If women at high risk for developing complications could be identified early, level of care could be triaged, limited resources could be correctly allocated and targeted interventions to prevent complications could be implemented. We updated a systematic review and meta-analysis and added single outcomes. Women with hypertensive disorders of pregnancy were included. Exposures were tests predicting adverse maternal and/or perinatal outcomes. We searched Medline, Embase, CINAHL, and Cochrane library from January 2016-February 2024. We included studies identified from the previous review. We calculated effect measures. For similar predictive tests and outcomes, area under the receiver-operating-characteristic curve (AUROC) were pooled. This study was registered by PROSPERO: CRD42022336368. Of the 2898 studies identified, 80 were included. Thirty were added from the previous review resulting in 110 included studies with 506,178 women. Despite more than 1500 tests being performed, most outcomes could not be pooled due to heterogeneity in populations, tests, and outcome definitions. For maternal outcomes, only studies reporting on the Pre-eclampsia Integrated Estimate of RiSk (fullPIERS) model could be pooled. For the composite outcome within 48-h the AUROC was 0.78 (95% CI 0.71-0.86, N=8). There was significant heterogeneity (I 2 =95.7%). For perinatal outcomes, data were pooled for pulsatility index in the umbilical artery and soluble FMS-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) ratio. Biomarkers like the sFlt-1/PlGF ratio showed promising predictive performance for some outcomes but were not externally validated. Despite including over 100 studies with more than 1500 predictors, we were unable to pool any single maternal outcomes and only a few individual perinatal outcomes. The fullPIERS model was externally validated, showing moderate accuracy which varied across studies and should be validated in each new population. Angiogenic biomarkers showed promise but need validation. Future studies should use standardized outcome measures and validate promising tests. VB is supported by the Swedish Research Council, Grant number 2020-01481. University of Gothenburg.

Research on the Improvement of Endothelial Cell Function and Trophoblast Apoptosis in Rats with Preeclampsia by Tanshinone IIA

Background Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, often the kidneys. Recent studies suggest that endothelial dysfunction and trophoblast apoptosis are involved in the pathogenesis of preeclampsia. Purpose To investigate the effects of tanshinone IIA (TIIA) on clinical symptoms, vascular endothelial function, and placental trophoblast apoptosis in preeclampsia rats. Materials and Methods Twenty-four pregnant Sprague-Dawley rats, between 8 and 10 weeks old, were randomly divided and allocated into three groups: Control, model, and treatment, with each group consisting of 8 rats. The control group received normal saline injections via the tail vein; the model group received NG-nitro-l-arginine methyl ester (l-NAME) to induce preeclampsia, followed by normal saline injections; and the treatment group received TIIA (10 mg/kg) via tail vein injection after preeclampsia induction with l-NAME. Various parameters were measured, including tail artery systolic pressure, 24-hour proteinuria, offspring and placental weight, levels of endothelial nitric oxide synthase (eNOS), endothelin-1 (ET-1), placental growth factor (PLGF), and soluble FMS-like tyrosine kinase 1 (sFlt-1) in serum, and expression of B-cell lymphoma-2 (Bcl-2) and Bcl-2-related X protein (Bax) in placental trophoblasts. Results TIIA treatment led to decreased tail artery systolic pressure and 24-hour urine protein levels, increased body and placental weights of offspring, and favorable changes in serum levels of ET-1, sFlt-1, eNOS, and PLGF. Moreover, TIIA treatment resulted in decreased Bax levels and apoptosis in placental trophoblasts, along with increased Bcl-2 levels. Conclusion TIIA can improve the clinical symptoms of preeclampsia in rats induced by l-NAME, alleviate the apoptosis of placental trophoblast cells, and improve vascular endothelial function.

Relationship between maternal serum sFlt-1 level and placenta accreta spectrum disorders in the third trimester

PurposeThis study aims to evaluate whether the third-trimester soluble fms-like tyrosine kinase-1 (sFlt-1) serum levels could be related to placenta accreta spectrum (PAS) disorders and the severity of postpartum blood loss.MethodsThis was a nested case–control study which compared serum sFlt-1 level between gravid women with or without PAS disorders. Spearman correlation analysis was conducted to explore the relationship between sFlt-1 level and the volume of postpartum blood loss. Confounding factors were adjusted to avoid the impact on the results.ResultsSixty gravid women were enrolled: 36 women in the PAS group and 24 women in the non-PAS group. Women in the PAS group had a median sFlt-1 level of 9407.1 [2745.9–21,691.5] pg/ml, whereas women in the non-PAS group had a median sFlt-1 level of 25,779.2 [14317.1–35,626.7] pg/ml, (p < 0.001). The sFlt-1 level was negatively related to the volume of postpartum blood loss (r = − 0.358, p = 0.041). After adjusting for maternal age and gestational age at blood taking, sFlt-1 level showed no significant relationship with PAS disorders (p = 0.245) and postpartum blood loss (p = 0.526).ConclusionThird-trimester sFlt-1 serum level is not independently associated with PAS disorders or postpartum blood loss after adjusting for confounding factors.

GPER Stimulation Attenuates Cardiac Dysfunction in a Rat Model of Preeclampsia.

Preeclampsia poses a substantial clinical challenge, characterized by maternal hypertension, cardiac dysfunction, and persistent cardiovascular risks for both the mother and offspring. Despite the known roles of the estrogen receptor (GPER [G protein-coupled estrogen receptor]) in placental development, its impact on cardiovascular aspects within a preeclampsia animal model remains unexplored. We propose that G-1, a GPER agonist, could have the potential to regulate not only hypertension but also cardiac dysfunction in rats with preeclampsia. To explore the influence of G-1 on preeclampsia, we used the reduced uterine perfusion pressure (RUPP) model. RUPP rats were administered either G-1 (100 µg/kg per day) or hydralazine (25 mg/kg per day). We conducted echocardiography to probe the intricate cardiac effects of G-1. The RUPP rat model revealed signs of hypertension and cardiac dysfunction and alterations in gene and protein expression within placental and heart tissues. G-1 treatment reduced blood pressure and reversed cardiac dysfunction in rats with preeclampsia. In contrast, administration of the vasodilator hydralazine reduced blood pressure without an improvement in cardiac function. In addition, while G-1 treatment restored the levels of sFLT-1 (soluble fms-like tyrosine kinase-1) in RUPP rats, hydralazine did not normalize this antiangiogenic factor. The therapeutic intervention of G-1 significantly mitigated the cardiovascular dysfunction observed in the RUPP rat model of preeclampsia. This discovery underscores the broader significance of understanding GPER's role in the context of preeclampsia-related cardiovascular complications.

Fibronectin as a predictor of preeclampsia

Since preeclampsia first emerged a few centuries ago, a substantial portion of humanity has been tormented by this disease, which has jeopardized and disrupted mankind. Numerous biological markers, including ENDOGLIN, PIGF (placental growth factor), SFLT 1(soluble fms like-tyrosine kinase 1), and PAPP-A (pregnancy associated plasma protein-A), suggest preeclampsia. It was beneficial for detecting preeclampsia, even if there was frequent mortality and morbidity among mothers because of the anticipated latency. Then another marker, fibronectin, was added to the picture. A better preeclampsia prognosis leads substantially to an overall decrease in maternal morbidity and mortality. The primary organ that manufactures circulating fibronectin, occasionally referred to as serum fibronectin, is the liver. To enable the extracellular and intracellular matrix to communicate and regulate cell behavior, fibronectin, an extracellular matrix element, primarily interacts with integrin receptors. Fibronectin is a diagnostic marker for a variety of ailments, such as muscular dystrophy, ovarian and stomach cancers, and gestational diabetes. Inflammatory changes result in the release of fibronectin into the bloodstream, and the main triggering factor of preeclampsia is the infiltration of various trophoblasts that injures endothelial tissues and induces inflammation. Therefore, the primary goal of our study was to establish that fibronectin is a biomarker of preeclampsia. To elucidate our perspective and evaluate whether fibronectin is relevant in preeclampsia prediction, we will conduct a qualitative evaluation of prior research and juxtapose it with the findings of the present study. Thus, early detection of preeclampsia could decrease the rate of maternal mortality and morbidity.

Stimulation of Angiotensin II Receptor Subtype 2 Reduces Preeclampsia-like Symptoms in a Mouse Model of Preeclampsia.

Angiotensin II (AngII) receptor subtype 1 (AT1R) is involved in the pathogenesis of preeclampsia (PE). Angiotensin II receptor subtype 2 (AT2R) can antagonize the effects of AT1R, but its effects during pregnancy are not known. We investigated the effect of AT2R on the pathogenesis of PE using a mouse model and recently developed AT2R agonist (compound 21 [C21]). Blastocysts collected from pregnant imprinting control region (ICR) mice were incubated with adenovirus containing the CD40L gene and transferred into the uterine horns of pseudo-pregnant ICR mice to express PE-like features. Osmotic pumps were placed subcutaneously on the dorsal side with C21 or saline. C21 reduced the plasma soluble fms-like tyrosine kinase 1 (sFlt-1) concentration, ameliorating hypertension. The splenic T and B cell profiles in model mice were analyzed by flow cytometry. The gated percentage of IFN-γ-positive Th cells was significantly increased and the percentage of plasma cells in B cells was significantly decreased; however, the percentages were not altered by C21. sFlt-1 and soluble endoglin concentrations in plasma were measured with an enzyme-linked immunosorbent assay, and sFlt-1 was reduced. C21 could become a candidate PE drug as it ameliorated the pathophysiology of PE as a result of decreased production of sFlt-1.

Abstract 16: A Novel H2 Relaxin B-Chain-Only Peptide Variant B7-33 Improves The Pathophysiology Of Placental Ischemia In The Reduced Uterine Perfusion Pressure Rat Model Of Preeclampsia

Background: Preeclampsia (PE) is a hypertensive pregnancy disorder, which occurs in approximately 10% of all gestations. The literature suggests the potential therapeutic role of H2 relaxin in PE. A novel H2 relaxin B-chain-only peptide variant B7-33 (27 amino acids without any disulfide bonds) has recently been developed. Objective: The goal of this study was to test the hypothesis that a novel H2 relaxin B-chain-only peptide variant B7-33 could improve the pathophysiology of placental ischemia in the Reduced Uterine Perfusion Pressure (RUPP) rat model of PE. Methods: The efficacy of B7-33 was evaluated in the RUPP model as described previously. RUPP rats are randomly assigned to 4 groups (N=8/group): 1) vehicle, 2) B733; 3) B733-Fc; and 4) B733-HSA. Rats are dosed twice weekly (i.v.) from GD10 to GD 20. On GD 18, rats are anesthetized with isoflurane, and carotid arterial catheters are inserted into the carotid artery, tunneled under the skin, and externalized at the back of the neck. On the following day, mean arterial pressure (MAP) is monitored with a pressure transducer (Cobe III Tranducer CDX Sema) and recorded continuously for 30 min. On GD18, uterine artery resistance index (UARI) of rats is measured by Doppler sonography. The nitric oxide bioavailability, soluble fms-like tyrosine kinase-1 (sFlt-1), and TNF-α) were measured by commercially available kits. Statistical comparisons were performed using analysis of variance with Duncan’s post hoc test. Results: The RUPP rats have increased MAP (122.2 ± 8.1 mm Hg), plasma TNF-α (223 ±11.4 pg/mL), and plasma sFlt-1(863 ±18.2 pg/mL) along with decreased NO index (14±2 µM) compared to normal pregnancy: MAP (102 ± 5.2 mm Hg); plasma TNF-α (28 ± 4.1 pg/mL); plasma sFlt-1(244 ± 9.4 pg/mL) and NO index (26 ±4.1 µM). Treatment with B733 and B7-33 fusion proteins significantly (*p&lt;0.05) lowers MAP, plasma TNF-α, and plasma sFlt-1 and increased NO index back to that of normal pregnancy. The B7-33 data are consistent with earlier data with serelaxin in the RUPP model. All fusions tested ameliorate hypertension in the RUPP animals. B7-33 normalizes BP and proteinuria in the DOCA rat model of preE. Conclusion: The conclusion of the study is that both B7-33 and B7-33 fusion proteins demonstrate efficacy in attenuating the symptoms of PE including hypertension and inflammation in RUPP model. We conclude that B7-33 is an ideal candidate for development as a novel therapeutic in preE.

B-flow/spatiotemporal image correlation M-mode ultrasound provides novel method to quantify spiral artery remodeling during normal human pregnancy.

During human pregnancy, placental extravillous trophoblasts replace vascular smooth muscle and elastic tissue within the walls of the uterine spiral arteries, thereby remodeling them into distensible low-resistance vessels to promote placental perfusion. The present study determined whether B-flow/spatiotemporal image correlation (STIC) M-mode ultrasonography provides an in-vivo imaging method able to digitally quantify spiral artery luminal distensibility as a physiological index of spiral artery remodeling during the advancing stages of normal human pregnancy. A prospective, longitudinal, observational study was conducted to quantify spiral artery distensibility (i.e. vessel luminal diameter at systole minus diameter at diastole) by B-flow/STIC M-mode ultrasonography during the first, second and third trimesters in 290 women exhibiting a normal pregnancy. Maternal serum levels of placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1), growth factors that modulate important events in spiral artery remodeling, were quantified in a subset of the women in the first, second and third trimesters of pregnancy. Median (interquartile range (IQR)) spiral artery distensibility increased progressively between the first (0.17 (0.14-0.21) cm), second (0.23 (0.18-0.28) cm) and third (0.26 (0.21-0.35) cm) trimesters of pregnancy (P < 0.0001 for all). Median (IQR) spiral artery volume flow increased progressively between the first (2.49 (1.38-4.99) mL/cardiac cycle), second (3.86 (2.06-6.91) mL/cardiac cycle) and third (7.79 (3.83-14.98) mL/cardiac cycle) trimesters (P < 0.001 for all). In accordance with the elevation in spiral artery distensibility, the median (IQR) ratio of serum PlGF/sFlt-1 × 103 levels increased between the first (7.2 (4.5-10.0)), second (22.7 (18.6-42.2)) and third (56.2 (41.9-92.5)) trimesters (P < 0.001 for all). The present study shows that B-flow/STIC M-mode ultrasonography provides an in-vivo imaging technology to quantify digitally the structural and physiological expansion of the walls of the spiral arteries during the cardiac cycle as a consequence of their transformation into compliant vessels during advancing stages of normal human pregnancy. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Abstract P195: Vascular MAPK/ERK Activation in sFTL-1-Induced Preeclampsia In Vivo

Vascular endothelial growth factor (VEGF) inhibition is linked to the development of hypertension and proteinuria in preeclampsia. This occurs as anti-angiogenic factors from the placenta contribute to pregnancy-related hypertension disorder. Soluble VEGF receptor fms-like tyrosine kinase-1 (sFLT-1) is an anti-angiogenic factor that counteracts VEGF. Levels of sFLT-1 are three times higher in preeclamptic placentas compared to those from normotensive pregnancies, and plasma sFLT-1 levels increase with the severity of preeclampsia. Infusing sFLT-1 in rodents induces hypertension, proteinuria, and glomerular endotheliosis, resembling the human condition of preeclampsia. Currently, there is no effective pharmacological treatment of preeclampsia, and in severe cases, early delivery is often the only effective treatment. In this study, we aim to determine how sFLT-1 exposure affects the activation of the vascular MAPK/ERK pathway and the contractility of the aorta ex-vivo using wire myography, to assess if the MAPK/ERK pathway can be a therapeutic target in preeclampsia. To this end, we treated pregnant female C57BL/6 mice from embryonic day E7.5 to E18.5 with either sFLT-1 (3.7mg/kg/day) or vehicle (phosphate-buffered saline) delivered by osmotic minipumps (intraperitoneal) and carried out non-invasive tail-cuff blood pressure measurements. After sacrifice, we isolated descending thoracic aorta for isometric tension measurements in a wire myograph. Infusion of sFLT-1 resulted in marked systolic blood pressure (SBP) elevation (D increase of 14 mmHg, P=0.0003) and augmented aortic phosphorylated-ERK activation (2-fold increase, P=0.040) by western blot and displayed impaired acetylcholine-induced endothelial relaxation in thoracic aortic segments (P&lt;0.05), providing in vivo evidence of increased vascular p-ERK activation, accompanied by higher SBP and endothelial dysfunction in sFLT-1 - indued mouse model of preeclampsia. Future experiments are aimed to test the effect of pharmacological ERK inhibition in sFLT-1 infusion in vivo . We hypothesize that sFLT-1-induced rise in SBP and vascular p-ERK could be prevented in vivo by treatment with the pharmacological ERK inhibitor.