Reduced Uterine Perfusion Pressure Surgery Research Articles

Elevated Renal Oxidative Stress and Na+ Transporters are Associated with Hypertension in Postpartum Preeclamptic Rats

Background: Approximately 5-10% of US pregnancies result in preeclampsia (PE). PE is characterized by new onset hypertension (HTN) during pregnancy and is usually accompanied by end-organ damage, especially in the kidneys. Postpartum (PP) women and dams that had PE have an increased risk of developing HTN and chronic kidney disease (CKD) later in life. However, mechanisms linking PE to the long-term development of HTN and CKD are unknown. One aspect that may contribute to renal injury in PP PE women and dams is oxidative stress. Elevated concentrations of oxidative stress have been shown to augment the abundance and activity of renal transporters to increase sodium (Na+) reabsorption and blood volume. These alterations in renal transporters can consequently increase Na+ and water to facilitate HTN. Thus, we hypothesize that at 6 weeks PP (~3 human years), PE dams will display increased oxidative stress, renal Na+ transporter abundance, and elevated blood pressure (BP). Methods: Pregnant Sprague Dawley rats were randomly assigned to two groups: normal (CON) and PE dams. On gestational day 14, the reduced uterine perfusion pressure surgery was performed to mimic placental ischemia and generate a model of PE. Dams gave birth naturally and weaned for 3 weeks. After 6 weeks PP, BP was measured via carotid catheterization, and kidneys were removed and sectioned. Western blots were used to quantify renal Na+ transporters: Na+ K+ 2Cl− transporter (NKCC2) in the kidney medulla (KM) and epithelial Na+ channel (ENaC) in both the kidney cortex (KC) and KM. Oxidative stress was evaluated by heat shock protein 1 (HSP-1), copper zinc superoxide dismutase (CuZnSOD), and manganese superoxide dismutase (MnSOD) via Western blots. Hydrogen peroxide (H2O2) and antioxidant capacity concentrations were assessed via colorimetric assays. Results: PP PE dams had increased BP (126.3±6.18vs105.7±3.74 mmHg, p<0.05) at 6 weeks after birth. KC HSP-1, H2O2, MnSOD, and antioxidant capacity were unchanged between groups. However, KC CuZnSOD protein abundance was decreased in PP PE dams (69.51±11.64vs100±5.73 IU/Protein/Control%, p<0.05). In the KM, HSP-1 abundance (113.7±3.3vs100±5.07 IU/Protein/Control%, p=0.06) and H2O2 concentrations (1.97±0.11vs1.31± 0.38 nM H2O2/mg Protein, p=0.08) were elevated in PP PE dams. MnSOD, CuZnSOD, and antioxidant capacity were unchanged between groups in the KM. No changes occurred in KC and KM ENaC protein abundance. However, NKCC2 protein abundance was elevated by ~50% in PP PE dams (151.71±22.17vs100±5.59 IU/Protein/Control%, p=0.06). Conclusion: In summary, BP, oxidative stress, and NKCC2 were elevated in PP PE dams at 6 weeks. Perhaps, the presence of oxidative stress in the KM may lead to increased NKCC2 abundance. However, more studies are warranted to make this conclusion. NKCC2 elevation may result in increased Na+ and water reabsorption, leading to an increase in BP. Future studies will assess the role of renal oxidative stress to regulate Na+ transporters in PP PE dams and determine the timeline after birth (PP) in which changes in oxidative stress, Na+ transporters, and BP occur. In summary, this study is clinically relevant because it indicates that both oxidative stress and NKCC2 in the KM, separately or together, may have a formative role in the pathogenesis of HTN and CKD in PP PE women later in life. This research was supported by the Neurobiology of Aging and Alzheimer’s Disease Training Program (funded by NIH training grant T32 AG020494). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Assessment of feto-placental oxygenation and perfusion in a rat model of placental insufficiency using T2* mapping and 3D dynamic contrast-enhanced MRI

IntroductionPlacental insufficiency may lead to preeclampsia and fetal growth restriction. There is no cure for placental insufficiency, emphasizing the need for monitoring fetal and placenta health. Current monitoring methods are limited, underscoring the necessity for imaging techniques to evaluate fetal-placental perfusion and oxygenation. This study aims to use MRI to evaluate placental oxygenation and perfusion in the reduced uterine perfusion pressure (RUPP) model of placental insufficiency. MethodsPregnant rats were randomized to RUPP (n = 11) or sham surgery (n = 8) on gestational day 14. On gestational day 19, rats imaged using a 7T MRI scanner to assess oxygenation and perfusion using T2* mapping and 3D-DCE MRI sequences, respectively. The effect of the RUPP on the feto-placental units were analyzed from the MRI images. ResultsRUPP surgery led to reduced oxygenation in the labyrinth (24.7 ± 1.8 ms vs. 28.0 ± 2.1 ms, P = 0.002) and junctional zone (7.0 ± 0.9 ms vs. 8.1 ± 1.1 ms, P = 0.04) of the placenta, as indicated by decreased T2* values. However, here were no significant differences in fetal organ oxygenation or placental perfusion between RUPP and sham animals. DiscussionThe reduced placental oxygenation without a corresponding decrease in perfusion suggests an adaptive response to placental ischemia. While acute reduction in placental perfusion may cause placental hypoxia, persistence of this condition could indicate chronic placental insufficiency after ischemic reperfusion injury. Thus, placental oxygenation may be a more reliable biomarker for assessing fetal condition than perfusion in hypertensive disorders of pregnancies including preeclampsia and FGR.

Edaravone Confers Neuroprotective, Anti-inflammatory, and Antioxidant Effects on the Fetal Brain of a Placental-ischemia Mouse Model.

Reduced uterine perfusion pressure (RUPP) is a well-established model which mimics many clinical features of preeclampsia (PE). Edaravone is a free radical scavenger with neuroprotective, antioxidant and anti-inflammatory effects against different models of cerebral ischemia. Therefore, we aimed to elucidate the different potential mechanisms through which PE affects fetal brain development using our previously established RUPP-placental ischemia mouse model. In addition, we investigated the neuroprotective effect of edaravone against the RUPP-induced fetal brain development alterations. On gestation day (GD) 13, pregnant mice were divided into four groups; sham (SV), edaravone (SE), RUPP (RV), and RUPP+edaravone (RE). SV and SE groups underwent sham surgeries, however, RV and RE groups were subjected to RUPP surgery via bilateral uterine ligation. Edaravone (3mg/kg) was injected via tail i.v. injection from GD 14-18. The fetal brains from different groups were collected on GD 18 and subjected to further investigations. The results showed that RUPP altered the structure of fetal brain cortex, induced neurodegeneration, increased the expression of the investigated pro-inflammatory markers; TNF-α, IL-6, IL-1β, and MMP-9. RUPP resulted in microglial and astrocyte activation in the fetal brains, inaddition to upregulation of Hif-1α and iNOS. Edaravone conferred a neuroprotective effect via alleviating the inflammatory response, restoring the neuronal structure and decreasing oxidative stress in the developing fetal brain. In conclusion, RUPP-placental ischemia mouse model could be a useful tool to further understand the underlying mechanisms of PE-induced child neuronal alterations. Edaravone could be a potential adjuvant therapy during PE to protect the developing fetal brain. The current study investigated the effects of a placenta-induced ischemia mouse model using reduced uterine perfusion pressure (RUPP) surgery on the fetal brain development and the potential neuroprotective effects of the drug edaravone. The study found that the RUPP model caused neurodegeneration and a pro-inflammatory response in the developing fetal brain, as well as hypoxia and oxidative stress. However, maternal injection of edaravone showed a strong ability to protect against these detrimental effects and target multiple pathways associated with neuronal damage. The current study suggests that the RUPP model could be useful for further study of the impact of preeclampsia on fetal brain development and that edaravone may have potential as a therapy for protecting against this damage.

Increased hippocampal cannabinoid 1 receptor expression is associated with protection from severe seizures in pregnant mice with reduced uterine perfusion pressure.

Eclampsia, new-onset seizures in pregnancy, can complicate preeclampsia, a hypertensive pregnancy disorder. The mechanisms contributing to increased risk of seizures in preeclampsia are not fully known. One mechanism could be abnormal endocannabinoid system (ECS) activity and impaired neuromodulation. Indeed, increased placental cannabinoid receptor 1 (CB1R) expression and reduced serum anandamide, a CB1R ligand, have been reported in preeclampsia patients. We hypothesized that reduced uterine perfusion pressure (RUPP), used to mimic preeclampsia, leads to changes in hippocampal CB1R expression, and that manipulating CB1R activity will change seizure severity in RUPP mice. Pregnant mice underwent sham or RUPP surgery on gestational day (GD)13.5. On GD18.5, mice received: no drug treatment, pentylenetetrazol (PTZ, 40 mg/kg), Rimonabant (10 mg/kg) + PTZ, or 2-AG (1 mg/kg) + PTZ. Behaviors were video recorded (15 min for Rimonabant and 2-AG, followed by 30 min for PTZ), and the hippocampus was harvested. The expression of CB1R and ECS proteins was measured in hippocampal homogenates, synaptosomes, and cytosol. Hippocampal CB1R increased in homogenates and cytosolic fraction, and was unchanged in synaptosomes of RUPP mice. Increased CB1R colocalization on glutamate-releasing neurons within hippocampal CA1 was observed in RUPP mice. Rimonabant modestly increased seizure scores over time in RUPP mice. PTZ after rimonabant pretreatment increased seizure scores and duration, while reducing latency in sham mice, with little to no change in RUPP mice. Furthermore, RUPP mice had lower seizure scores over time than sham following CB1R blockade and activation. These data suggest that RUPP modifies CB1R activity prior to seizure induction, which protects mice from worse seizure outcomes.

Reduced uterine perfusion increases hippocampal cannabinoid receptor 1 expression and reduces pentylenetetrazol-induced seizures after rimonabant pre-treatment

Eclampsia, new-onset seizures in pregnant women, can affect women with preeclampsia, a hypertensive pregnancy disorder. Eclampsia is associated with high maternal and fetal morbidity and mortality. The mechanisms contributing to increased risk of seizures in preeclampsia patients are not fully known. One potential mechanism could be abnormal endocannabinoid system activity, and abnormal neuro-modulation. Indeed, increased placental cannabinoid receptor 1 (CB1R) expression and reduced serum concentration of anandamide, a ligand that activates the CB1R, have been reported in preeclampsia patients. We hypothesized that reduced uterine perfusion pressure (RUPP) in mice leads to differences in hippocampal CB1R expression and that inhibiting CB1R activity will increase seizure sensitivity in RUPP mice. Pregnant mice underwent sham (n=5) or RUPP (n=5) surgery on gestational day (GD) 13.5. On GD 18.5, the hippocampus was harvested and processed for Western blot to analyze the expression of CB1R in homogenates, synaptosomal fraction, and cytosolic fraction of the hippocampus. To determine if blocking CB1R increases sensitivity to pentylenetetrazol (PTZ)-induced seizures, additional sham (n=7) and RUPP (n=7) mice were pretreated with 10 mg/kg of rimonabant, video monitored for 15 minutes, injected with 40 mg/kg of PTZ and video monitored for an additional 30 minutes before being sacrificed. Seizures were scored using a modified 7-point Racine scale. In hippocampal homogenates, CB1R expression increased in RUPP mice (p=0.056). There was no difference in CB1R expression in the synaptosomal fraction (p=0.095); however, there was an increase in CB1R expression in the cytosolic fraction of RUPP mice (p=0.016). Immunofluorescence analysis showed increased CB1R colocalization on both glutamate- and GABA- releasing neurons within hippocampal CA1 (p=0.029; p=0.057, respectively). CB1R blockade induced a maximum seizure score of 4 in both groups but led to higher seizure scores over time in RUPP mice (p=0.025). PTZ injection after rimonabant pretreatment increased seizure scores in sham (p<0.05), non-significantly increased scores in RUPP (p=0.075), increased duration of seizures in sham but not RUPP mice (p=0.021; p=0.245, respectively), and reduced latency to seizures in sham mice (p=0.019) while there was no further decrease in seizure latency in RUPP (p=0.374) mice. Furthermore, during the first 15 minutes of PTZ exposure, RUPP mice had lower seizure scores over time than sham [p(TimexRUPP)=0.002] following CB1R blockade. These data suggest that RUPP induces abnormal CB1R expression, resulting in increased sensitivity to seizures after CB1R blockade, while protecting against worse seizures when challenged with the pro-convulsant, PTZ. NIH R00HL129192, R00HL129192-S1, COBRE Pilot Grant, T32HL105324, William Townsend Porter Pre-Doctoral Fellowship from the American Physiological Society, 1F99NS129125-01. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 050: Endothelial Cell Mineralocorticoid Receptor Deletion Improves Endothelial Function, Blood Pressure And Fetal Growth In The RUPP Mouse Model Of Preeclampsia

Preeclampsia (PE) is a hypertensive disorder of pregnancy that causes adverse pregnancy outcomes. Progesterone in pregnancy increases endothelial mineralocorticoid receptor (ECMR) expression, which we showed mediates endothelial function in hypertensive female mice, however, whether ablating endothelial dysfunction in PE improves pregnancy outcomes is unknown. We hypothesized that improving endothelial function via ECMR deletion increases fetal growth and ablates hypertension in the reduced uterine perfusion pressure (RUPP) PE mouse. Pregnant ECMR-intact (WT) and -deficient (KO) mice underwent RUPP or sham surgery on GD13 and sacrificed on GD18 (WT Sham=9, WT RUPP=5, KO Sham=6, KO RUPP=6). Vascular function was measured via wire myography on 2 nd order mesenteric arteries and thoracic aorta. Systolic blood pressure (BP) was measured by radiotelemetry in a subset of mice. RUPP did not decrease maternal weights in either WT or KO mice (P>0.05) but decreased pup weight (726±20 WT+Sham vs 660±11mg WT+RUPP, *P<0.05) and fetal demise (16±4 vs 28±4% resoprtions/litter, *P<0.05) in WT pregnant mice, however, not in KO mice (710±15 KO+Sham vs 693±19 mg KO+RUPP, P>0.05, and 13±5 vs 28±12% resoprtions/litter, P>0.05), indicating KO protected fetal growth. RUPP reduced endothelial-dependent, acetylcholine-mediated vascular relaxation (10 -9 -3x10 -5 M) in WT, but not KO pregnant mice (*P<0.05, 2-way ANOVA w/ RM), but not aorta ACh-mediated relaxation (P>0.05). Nitric oxide synthase (NOS) inhibitor LNAME ablated differences in ACh-mediated relaxation between WT Sham and WT RUPP (P>0.05), with no differences observed in KO Sham or KO RUPP, in both aorta and mesenteric arteries, indicating RUPP impaired endothelial function via decreasing NOS activity. Preliminary data demonstrates RUPP increased BP on GD15-17 in WT (127±21 mmHg, N=3), however, not in KO pregnant mice (111±4, N=2). RUPP also ablated circadian rhythm in WT, but not KO, pregnant mice from GD15-18. Collectively, these data indicate that ECMR activation induces reduced pup weight, endothelial dysfunction and hypertension in the RUPP model which may lead to clinical studies for consideration of specific MR antagonists as therapeutic options for endothelial dysfunction in PE pregnancies.

Abnormal cerebral microvascular perfusion and reactivity in female offspring of reduced uterine perfusion pressure (RUPP) mice model

Children born from women with preeclampsia have alterations in cerebral neurovascular development and a high risk for developing cognitive alterations. Because cerebral blood vessels are critical components in cerebrovascular development, we evaluated the brain microvascular perfusion and microvascular reactivity (exposed to external stimuli of warm and cold) in pups born to preeclampsia-like syndrome based on the reduction of uterine perfusion (RUPP). Also, we evaluate the angiogenic proteomic profile in those brains. Pregnant mice showed a reduction in uterine flow after RUPP surgery (−40 to 50%) associated with unfavorable perinatal results compared to sham mice. Furthermore, offspring of the RUPP mice exhibited reduced brain microvascular perfusion at postnatal day 5 (P5) compared with offspring from sham mice. This reduction was preferentially observed in females. Also, brain microvascular reactivity to external stimuli (warm and cold) was reduced in pups of RUPP mice. Furthermore, a differential expression of the angiogenic profile associated with inflammation, extrinsic apoptotic, cancer, and cellular senescence processes as the primary signaling impaired process was found in the brains of RUPP-offspring. Then, offspring (P5) from preeclampsia-like syndrome exhibit impaired brain perfusion and microvascular reactivity, particularly in female mice, associated with differential expression of angiogenic proteins in the brain tissue.

Endothelial Cell Mineralocorticoid Receptor (ECMR) deletion improves fetal growth and vascular function in the RUPP mouse model of preeclampsia

Preeclampsia (PE), a hypertensive disorder of pregnancy, induces adverse pregnancy outcomes including fetal growth restriction (FGR) and afflicts ~5‐10% of pregnancies. Compelling clinical data indicate that PE risk and severity in pregnant women is strongly associated with endothelial dysfunction. Previous work by our group shows that deletion of endothelial cell mineralocorticoid receptors (ECMR) improves endothelial function in premenopausal hypertensive female mice, however whether ECMR promotes endothelial dysfunction in PE is unknown. We tested the hypothesis that ECMR deletion improves FGR and endothelial function in a mouse model of PE, the reduced uterine perfusion pressure (RUPP) mouse. Pregnant ECMR‐intact (WT) and ECMR‐deficient (KO) mice were randomized to RUPP or sham surgery on GD13 and sacrificed on GD18 (WT Sham=6, WT RUPP=5, KO Sham=7, KO RUPP=6). Vascular function was measured via wire myography on 2nd order mesenteric arteries. Conscious blood pressure was measured by radiotelemetry throughout pregnancy in a subset of mice. RUPP surgery did not decrease maternal weights in either WT or KO mice (P>0.05) at GD18. RUPP surgery significantly decreased GD18 pup weight, a measure of FGR, (726±20mg WT+Sham vs 660±11mg WT+RUPP, *P<0.05) and trended to decrease placental efficiency (pup/placenta weight) (8.23±0.23 WT+Sham vs 7.45±0.22 WT+RUPP P=0.13) in WT pregnant mice. ECMR deletion protected pregnant mice both from RUPP‐induced reductions in pup weight (710±20mg KO+Sham vs 690±20mg KO+RUPP) and decreases in placental efficiency (7.63±0.19 KO+Sham vs 7.76±0.31 KO+RUPP). RUPP reduced acetylcholine‐mediated relaxation (10‐9‐3x10‐5 M) in mesenteric arteries of WT pregnant mice but not KO pregnant mice (*P<0.05, 2‐way ANOVA, repeated measures), indicating RUPP induced endothelial dysfunction in WT mice only. Preincubation with nitric oxide (NO) synthase inhibitor LNAME ablated differences in Ach‐mediated relaxation between WT+sham and WT+RUPP mice (P>0.05), indicating that reductions in endothelial function in WT+RUPP mice were mediated by reduced NO. However, ECMR deletion as a variable increased Ach‐mediated relaxation in the presence of LNAME in both Sham and RUPP mice (*P<0.05). Therefore, ECMR deletion may have protected pregnant mice from endothelial dysfunction via a non‐NO mechanism. RUPP did not increase a‐receptor agonist phenylephrine (Phe)‐induced constriction in WT mice, however, ECMR deletion as a variable decreased Phe‐mediated constriction independent of RUPP surgery indicating that ECMR deletion reduces smooth muscle‐mediated vasoconstriction in pregnant sham and RUPP mice. These data indicate that specific deletion of ECMR improves vascular function to increase vasodilation and prevent constriction in PE pregnancy. Preliminary data further indicates that systolic blood pressure increased from GD8‐18 (pre‐post RUPP) in WT+RUPP but decreased in KO+RUPP pregnant mice (2.7 vs ‐8.6 DmmHg, respectively, N=1). Lastly RUPP surgery trended to increase plasma levels of the ECMR agonist corticosterone in WT pregnant mice (2.03±0.4pg/ml WT+Sham vs 3.33±0.95pg/ml WT+RUPP). Collectively, these data indicate that ECMR activation promotes FGR, vascular dysfunction and hypertension in the RUPP model of PE which may lead to clinical studies for the consideration of specific MR antagonists as therapeutic options for PE pregnancies.

Angiotensin II type 1 receptor agonistic autoantibody blockade improves postpartum hypertension and cardiac mitochondrial function in rat model of preeclampsia

Women with preeclampsia (PE) have a greater risk of developing hypertension, cardiovascular disease (CVD), and renal disease later in life. Angiotensin II type I receptor agonistic autoantibodies (AT1-AAs) are elevated in women with PE during pregnancy and up to 2-year postpartum (PP), and in the reduced uterine perfusion pressure (RUPP) rat model of PE. Blockade of AT1-AA with a specific 7 amino acid peptide binding sequence (‘n7AAc’) improves pathophysiology observed in RUPP rats; however, the long-term effects of AT1-AA inhibition in PP is unknown. Pregnant Sprague Dawley rats were divided into three groups: normal pregnant (NP) (n = 16), RUPP (n = 15), and RUPP + ‘n7AAc’ (n = 16). Gestational day 14, RUPP surgery was performed and ‘n7AAc’ (144 μg/day) administered via osmotic minipump. At 10-week PP, mean arterial pressure (MAP), renal glomerular filtration rate (GFR) and cardiac functions, and cardiac mitochondria function were assessed. MAP was elevated PP in RUPP vs. NP (126 ± 4 vs. 116 ± 3 mmHg, p < 0.05), but was normalized in in RUPP + ‘n7AAc’ (109 ± 3 mmHg) vs. RUPP (p < 0.05). PP heart size was reduced by RUPP + ’n7AAc’ vs. RUPP rats (p < 0.05). Complex IV protein abundance and enzymatic activity, along with glutamate/malate-driven respiration (complexes I, III, and IV), were reduced in the heart of RUPP vs. NP rats which was prevented with ‘n7AAc’. AT1-AA inhibition during pregnancy not only improves blood pressure and pathophysiology of PE in rats during pregnancy, but also long-term changes in blood pressure, cardiac hypertrophy, and cardiac mitochondrial function PP.

Abstract 31: Esomeprazole Improves Blood Pressure, Intrauterine Growth, Inflammation, And Vascular Function During Placental Ischemia Through Inhibition Of NLRP3

Preeclampsia (PE), a multisystem hypertensive disorder of pregnancy is characterized by intrauterine growth restriction (IUGR), inflammation, and vascular dysfunction. NLRP3 inflammasome is a cytoplasmic complex that mediates inflammation and is implicated in CVD. Clinical studies show an association between PE and increased placental NLRP3 expression. We hypothesized that inhibition of NLRP3 using (1) a specific NLRP3 small molecule inhibitor, MCC950 (M9, 20 mg/kg/d, i.p.) or (2) esomeprazole (ESO, 3.5 mg/kg/d, oral), a therapeutic that is safe in pregnancy, would improve MAP, inflammation, IUGR, and vascular dysfunction in the reduced uterine perfusion pressure (RUPP) rat model of placental ischemia. Sham (S) or RUPP surgery was performed in pregnant Sprague Dawley rats on gestation day (GD) 14. A subset of rats from both groups received either vehicle, M9, or ESO on GD14-19 (n=9/group). On GD18, Uterine Artery Resistance Index (UARI) was measured via Doppler Ultrasound. MAP, fetal, and placental weight were measured, and blood and tissues were processed for additional analyses on GD19. MAP (mmHg) was elevated in RUPP (133±1) vs S (108±2; p&lt;0.05). Treatment with M9 or ESO in RUPP decreased MAP (111±1 and 115±3, respectively; p&lt;0.05 vs RUPP). Fetal weight (g) was reduced in RUPP (2.1±0.04) vs S (2.4±0.05), and ESO normalized fetal weight (2.4±0.01; p&lt;0.05 vs RUPP). Placental NLRP3 mRNA expression increased 5-fold in RUPP vs S (p&lt;0.05); and was less than 2 fold in M9 and ESO treated RUPP rats (p&lt;0.05 vs RUPP). Inflammatory T-helper 17 and cytolytic NK cells, evaluated by flow cytometry, were increased in the circulation, placenta, and kidney of RUPP vs S controls. Treatment with M9 or ESO normalized both cell populations in all tissues (p&lt;0.05 vs RUPP). UARI was increased in RUPP (0.71±0.03) versus S (0.56±0.01; p&lt;0.05) and was decreased to 0.48±0.01 in M9 and 0.61±0.03 in ESO-treated RUPPs (p&lt;0.05 vs RUPP). Renal vascular resistance (mmHg/mL/min/g) was increased in RUPP (42±8) vs S (23±4, p&lt;0.05) and was normalized to 26±3 after treatment with M9 (p&lt;0.05 vs RUPP). These data implicate NLRP3 in mediating inflammation and vascular dysfunction to cause maternal HTN and IUGR in RUPP; and identify NLRP3 as a potential target and ESO as a potential therapeutic for PE.

Abstract 25: Inhibition Of The Agonistic Ang II Type 1 Receptor Autoantibody In A Rat Model Of Preeclampsia Improves Uteroplacental Perfusion And Fetal Growth In Late Gestation

Placenta ischemia, the initiating factor in preeclampsia (PE), is associated with intrauterine growth restriction (IUGR) and increased blood pressure (BP) in offspring. Yet, the only treatment for PE is delivery of the baby and placenta. The Reduced Uterine Perfusion Pressure (RUPP) rat model induced by placental ischemia at gestational day 14 (G14) mimics many facets of human PE including pregnancy-specific hypertension, an increase in the agonistic ANG II Type 1 receptor autoantibody (AT1-AA), IUGR and increased BP in the offspring. Inhibition of AT1-AA using an epitope-binding inhibitory peptide ('n7AAc') attenuates increased BP at gestational day 19 in the RUPP. Yet, whether use of ‘n7aac’ improves fetal growth and mitigates increased BP in the offspring is unknown. Thus, we tested the hypothesis that maternal administration of ‘n7aac’ improves fetal growth by attenuating reduced uterine blood flow and impaired placental remodeling. Sham or RUPP surgery was performed at G14 with administration of vehicle or ‘n7aac’ (144μg/day) via mini osmotic pump until gestational day 20 (G20). At G20 uterine artery resistance index was significantly elevated in vehicle RUPP (0.69±0.02 mm/s n=10) compared to vehicle Sham (0.48±0.02 mm/s n=8) (P&lt;0.0001) and not increased in treated RUPP (0.49±0.02 mm/s n=10) or treated Sham (0.48±0.02 mm/s n=9). Fetal weight was significantly reduced in vehicle RUPP (3.24±0.2 g) compared to vehicle Sham (3.92±0.05 g) (P=0.013) and not decreased in treated RUPP (3.70±0.04 g) or Sham (3.98±0.10 g). Litter size of viable pups at G20 was only reduced in treated RUPP (5.3±1.4) compared to vehicle Sham (11.56±0.7) (P=0.003). Importantly, using in vivo imaging, little to no auto fluorescence of rhodamine-labeled peptide (480 μg/kg/day, n=4) was detectable in the pups at G20. Thus, our results demonstrate that maternal treatment with ‘n7aac’ in the RUPP rat model of PE improve UARI, which is associated with improved fetal weight at G20 in response to placental ischemia. Whether this benefit continues to birth and mitigates increased BP in IUGR offspring is unknown but is the focus of future studies. In conclusion, inhibition of the AT1AA during PE may not only provide benefit to the mother, but may also be associated with benefit in the offspring.

Soluble guanylate cyclase stimulation in late gestation does not mitigate asymmetric intrauterine growth restriction or cardiovascular risk induced by placental ischemia in the rat.

Stimulation of soluble guanylate cyclase (sGC) improves fetal growth at gestational day 20 in the reduced uterine perfusion pressure (RUPP) rat model of placental ischemia suggesting a role for sGC in the etiology of intrauterine growth restriction (IUGR). This study tested the hypothesis that stimulation of sGC until birth attenuates asymmetric IUGR mitigating increased cardiovascular risk in offspring. Sham or RUPP surgery was performed at gestational day 14 (G14); vehicle or the sGC stimulator Riociguat (10 mg/kg/day sc) was administered G14 until birth. Birth weight was reduced in offspring from RUPP [intrauterine growth restricted (IUGR)], sGC RUPP (sGC IUGR), and sGC Sham (sGC Control) compared with Sham (Control). Crown circumference was maintained, but abdominal circumference was reduced in IUGR and sGC IUGR compared with Control indicative of asymmetrical growth. Gestational length was prolonged in sGC RUPP, and survival at birth was reduced in sGC IUGR. Probability of survival to postnatal day 2 was also significantly reduced in IUGR and sGC IUGR versus Control and in sGC IUGR versus IUGR. At 4 mo of age, blood pressure was increased in male IUGR and sGC IUGR but not male sGC Control born with symmetrical IUGR. Global longitudinal strain was increased and stroke volume was decreased in male IUGR and sGC IUGR compared with Control. Thus late gestational stimulation of sGC does not mitigate asymmetric IUGR or increased cardiovascular risk in male sGC IUGR. Furthermore, late gestational stimulation of sGC is associated with symmetrical growth restriction in sGC Control implicating contraindications in normal pregnancy.NEW & NOTEWORTHY The importance of the soluble guanylate cyclase-cGMP pathway in a rat model of placental ischemia differs during critical windows of development, implicating other factors may be critical mediators of impaired fetal growth in the final stages of gestation. Moreover, increased blood pressure at 4 mo of age in male intrauterine growth restriction offspring is associated with impaired cardiac function including an increase in global longitudinal strain in conjunction with a decrease in stroke volume, ejection fraction, and cardiac output.

Effect of edaravone on pregnant mice and their developing fetuses subjected to placental ischemia

Growing evidence indicates that reduced uterine perfusion pressure (RUPP) triggers the cascade of events leading to preeclampsia. Edaravone is a powerful free radical scavenger used for the treatment of ischemia/reperfusion diseases due to its anti-oxidative stress and anti-inflammatory properties. Here we investigate the effect of edaravone (3 mg/kg) on different maternal and fetal outcomes of RUPP-induced placental ischemia mice model. RUPP surgery was performed on gestation day (GD) 13 followed by edaravone injection from GD14 to GD18, sacrifice day. The results showed that edaravone injection significantly decreased the maternal blood pressure (113.2 ± 2.3 mmHg) compared with RUPP group (131.5 ± 1.9 mmHg). Edaravone increased fetal survival rate (75.4%) compared with RUPP group (54.4%), increased fetal length, weights, and feto-placental ratio (7.2 and 5.7 for RUPP and RUPP-Edaravone groups, respectively) compared with RUPP group. In addition, RUPP resulted in many fetal morphological abnormalities as well as severe delayed ossification, however edaravone decreased the morphological abnormalities and increased the ossification of the fetal endoskeleton. Edaravone improved the histopathological structure of the maternal kidney and heart as well as decreased the elevated blood urea and creatinine levels (31.5 ± 0.15 mg/dl (RUPP), 25.6 ± 0.1 mg/dl (RUPP+edaravone) for urea and 5.4 ± 0.1 mg/dl (RUPP), 3.5 ± 0.1 mg/dl (RUPP+edaravone) for creatinine) and decreased cleaved caspase-3 expression in the maternal kidney. In conclusion, this study demonstrated that our RUPP mice model recapitulated preeclampsia symptoms and edaravone injection ameliorated most of these abnormalities suggesting its effectiveness and potential application in preeclampsia treatment regimes.

Angiotensin II type 1 receptor autoantibody blockade improves cerebral blood flow autoregulation and hypertension in a preclinical model of preeclampsia

ABSTRACT Introduction:Women with preeclampsia (PE) and reduced uterine perfusion pressure (RUPP) pre-clinical rat model of PE have elevated angiotensin II type 1 receptor agonistic autoantibodies (AT1-AA) and cerebrovascular dysfunction. Methods:Sprague Dawley rats had RUPP surgery with/without AT1-AA inhibitor (‘n7AAc’144 μg/day) osmotic minipumps. Mean arterial pressure (MAP), CBF autoregulation, blood brain barrier (BBB) permeability, cerebral edema, oxidative stress, and eNOS were assessed. Results:‘n7AAc’ improved MAP, restored CBF autoregulation, prevented cerebral edema, elevated oxidative stress, and increased phosphorylated eNOS protein in RUPP rats. Conclusion:Inhibiting the AT1-AA in placental ischemic rats prevents hypertension, cerebrovascular dysfunction, and improves cerebral metabolic function.

Abstract P208: Imaging The Longitudinal Reduction In Placental Ischemia In Response To Therapeutic Intervention For Preeclampsia

Preeclampsia is believed to be induced by abnormal vascular remodeling and the resulting placental ischemia during early development. Sildenafil, a phosphodiesterase-5 inhibitor, reduces the maternal symptoms of preeclampsia by promoting angiogenesis and enhancing NO-mediated vasodilation. However, the effect of sildenafil on in vivo placental function has not been demonstrated. We performed longitudinal spectral photoacoustic (sPA) imaging of placental therapeutic response to sildenafil in the reduced uterine perfusion pressure (RUPP) model of preeclampsia. Sprague Dawley rats were administered sildenafil (S) via drinking water beginning on gestational day (GD) 11. Imaging was performed on GD14, 16, and 18 with the RUPP procedure implemented after the first imaging session. sPA images of oxygenation show that the placental ischemia induced by the RUPP surgery (RUPP, n=8, 48%; NP, n=8, 54%), was effectively eliminated by treatment with sildenafil (RUPP+S, n=8, 53%, p&lt;0.05). In addition to improved placental oxygenation, sildenafil was also found to reduce mean arterial pressure in RUPP animals by GD18 (RUPP, 110 mmHg; RUPP+S, 98 mmHg; p&lt;0.05), consistent with prior reports. Our studies demonstrate that sPA imaging can detect changes in placental oxygenation which could be used to indicate in vivo placental therapeutic response. Figure 1: Placental hypoxia in the RUPP is improved by treatment with sildenafil on GD16. B-mode US images (a, c) of anatomy were used to manually select the placenta (p) and average placental oxygenation was calculated. A custom red-blue oxygenation colormap was then overlaid for visualization (b, d). Scale bars = 3mm.

Vitamin D deficiency contribute to the development of preeclampsia through increased sFlt‐1 production and impaired vascular function

Preeclampsia (PE) is a pregnancy‐specific syndrome that affects 5~8% pregnancies and is a leading cause of maternal and neonatal morbidity and mortality. Although the underlying mechanism remains unclear, PE is widely accepted to be induced, in part, by uteroplacental ischemia, which leads to increased antiangiogenic factors, such as sFlt‐1, which antagonizes the angiogenic factors, causing widespread vascular dysfunction. Vitamin D deficiency (VDD) is a widespread public health issue, and increasing studies suggested that VDD is a possible risk factor for the development of PE; however, the underlying mechanism that contributes to the increased risk of preeclampsia in vitamin D deficient patients is not clear. We tested the hypothesis that vitamin D deficiency contributes to the development of PE in a placental ischemic rat model by increasing sFlt‐1 production and impairing vascular function. We first induced VDD in Sprague‐Dawley rats (DYET 119273 vs 110842, Dyets Inc., USA) prior to RUPP (Reduced Uterine Perfusion Pressure) surgery on gestational day (GD) 14. Blood pressure was monitored via carotid catheter. On GD19, uterine arteries were harvested to determine vascular reactivity on a wire myograph. We found that RUPP surgery significantly increased mean arterial blood pressure as expected(Ctrl+Sham, n=12, 102±10 mmHg; Ctrl+RUPP, n=12, 117±11 mmHg; P&lt;0.01), and this was significantly enhanced by vitamin D deficiency (VDD+RUPP, n=12, 136±11 mmHg; P&lt;0.01). Plasma sFlt‐1 concentrations were significantly increased in VDD rats (n=12, 117±15 pg/mL) compared to the control group(n=12, 49±17 pg/mL)(P&lt;0.05), and VEGF concentrations were significantly decreased(Ctrl, n=12, 1899±371 pg/mL; VDD, n=6, 1071±249 pg/mL, P&lt;0.05). VDD induced endothelial dysfunction in uterine arteries (% relaxation, control, n=6, 95±7%; VDD, n=6, 37±11%, P&lt;0.05). The circulating biomarkers for endothelial dysfunction also significantly increased. The E‐Selectin increased from 5166±1217 pg/mL to 5756±1053 pg/mL (P&lt;0.05). The ICAM‐1 levels increased from 3.15±1.03 ng/mL to 3.50±0.94 ng/mL (P&lt;0.05). The VCAM‐1 level increased from 44±13 ng/mL to 53±11 ng/mL (p&lt;0.05). These results suggest that vitamin D deficiency contributes to the onset of preeclampsia by increased sFlt‐1 production and impaired vascular function.Support or Funding InformationThis research was supported by the National Natural Science Foundation of China (81601318) and Shandong Province Health and Medical Science and Technology Program (2016WS0668), Weifang Medical University (No. 2017BSQD11).

Angiotensin II Type I Receptor Agonistic Autoantibody Blockade Improves Cerebral Blood Flow Autoregulation, Blood Brain Barrier Permeability, and Hypertension in the Pre‐Clinical Rat Model of Preeclampsia

BackgroundPreeclampsia (PE) is a pregnancy disorder that is characterized by an increase in blood pressure, angiotensin II type1 receptor agonistic autoantibodies (AT1‐AA), and neurological complications. The pre‐clinical RUPP (reduced uterine perfusion pressure) rat model of PE displays many of the clinical pathologies associated with PE, such as increased blood pressure, AT1‐AAs, blood brain barrier (BBB) permeability, and impaired cerebral blood flow (CBF) autoregulation.HypothesisWe hypothesized that specific inhibition of AT1‐AA, using the epitope binding 7 amino acid peptide sequence (7AA), will improve blood pressure, BBB integrity, and CBF autoregulation in RUPP rats.MethodsSprague Dawley rats, were divided into 3 groups: normal pregnant (NP) (n=19), RUPP (n=19), and RUPP+AT1‐AA inhibition (7AA) (n=21). RUPP surgery was performed on gestational day (GD) 14 and 7AA (2μg/μl) was administered via osmotic minipumps. GD 19, mean arterial pressure (MAP) was determined and BBB permeability was assessed using the in‐vivo imaging system (IVIS). CBF was measured by laser Doppler flowmetry through a 4 mm x 4 mm cranial window under anesthesia. MAP was elevated step‐wise from 100–190 mmHg by infusion of phenylephrine to determine changes in CBF.ResultsMAP was increased in RUPP vs NP (124±3 vs 100±1 mmHg, p&lt;0.05) and decreased in RUPP+7AA vs RUPP (105±2 vs 124±3 mmHg, p&lt;0.05) rats. Using IVIS, Texas Red/FITC green fluorescent imaging was decreased in RUPP+7AA vs RUPP (0.2±0.001 vs 0.6±0.001, p&lt;0.05), indicating improvement in BBB permeability with AT1‐AA inhibition. CBF autoregulation was impaired in RUPP vs NP rats at 140 mmHg (142±7 vs 119±4%, p&lt;0.05) and 160 mmHg (157±10 vs 129±6%, p&lt;0.05) (both pressures are within the normal CBF autoregulatory range). AT1‐AA inhibition prevented impaired CBF at 140mmHg (125±5 RUPP+7AA vs 142±7% RUPP, p&lt;0.05) and 160 mmHg (125±9 RUPP+7AA vs 157±10% RUPP, p&lt;0.05). Furthermore, the increases in CBF at pressures above the autoregulatory range, 180 mmHg (122±10 vs 198±17%, p&lt;0.05) and 190 mmHg (123±11 vs 208±19%, p&lt;0.05), was prevented in RUPP+7AA vs RUPP, respectively.ConclusionAT1‐AA inhibition improved blood pressure, BBB permeability, and CBF autoregulation in the pre‐clinical RUPP rat model of PE, indicating that AT1‐AA inhibition may be a potential therapy used to improve neurological complications during PE.Support or Funding InformationSupported: AHA18CDA34110264

L-(+)-Ergothioneine Significantly Improves the Clinical Characteristics of Preeclampsia in the Reduced Uterine Perfusion Pressure Rat Model

Preeclampsia is a multifactorial hypertensive disorder of pregnancy founded on abnormal placentation, and the resultant placental ischemic microenvironment is thought to play a crucial role in its pathophysiology. Placental ischemia because of fluctuations in the delivery of oxygen results in oxidative stress, and recent evidence suggests that mitochondrial dysfunction may be a prime mediator. However, large clinical trials of therapeutic antioxidants such as vitamins C and E for the treatment of preeclampsia have been disappointing. L-(+)-ergothioneine (ERG)-an unusual amino acid betaine derived from histidine-has important cytoprotective and antioxidant properties under conditions of high oxidative stress. In this study, we investigated the potential therapeutic effects of administration of ERG in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. ERG (25 mg/kg per day) was administered to rats on gestational day 11. On gestational day 14, RUPP surgery was performed, and on gestational day 19, blood pressure (mean arterial pressure) and fetal growth were measured. Production of mitochondria-specific H2O2 was analyzed in vivo in kidney samples. ERG ameliorated the hypertension (129±3 versus 115±4 mm Hg; P=0.01; n=8) and significantly increased pup weight in RUPP rats. ERG also significantly decreased circulating levels of antiangiogenic sFlt-1 (soluble fms-like tyrosine kinase-1) in RUPP rats (1367±245 pg/mL; P=0.04). Mitochondria-specific H2O2 (0.022±0.003 versus 0.029±0.001; MitoP/B ratio, n=3; P=0.05) was also significantly decreased in kidney tissue in RUPP rats treated with ERG. These data support the potential use of ERG for the treatment of preeclampsia.

Blockade of endogenous angiotensin II type I receptor agonistic autoantibody activity improves mitochondrial reactive oxygen species and hypertension in a rat model of preeclampsia

Preeclampsia (PE) is characterized by new-onset hypertension that usually occurs in the third trimester of pregnancy and is associated with oxidative stress and angiotensin II type 1 receptor agonistic autoantibodies (AT1-AAs). Inhibition of the AT1-AAs in the reduced uterine perfusion pressure (RUPP) rat, a model of PE, attenuates hypertension and many other characteristics of PE. We have previously shown that mitochondrial oxidative stress (mtROS) is a newly described PE characteristic exhibited by the RUPP rat that contributes to hypertension. However, the factors that cause mtROS in PE or RUPP are unknown. Thus, the objective of the current study is to use pharmacologic inhibition of AT1-AAs to examine their role in mtROS in the RUPP rat model of PE. AT1-AA inhibition in RUPP rats was achieved by administration of an epitope-binding peptide ('n7AAc'). Female Sprague-Dawley rats were divided into the following two groups: RUPP and RUPP + AT1-AA inhibition (RUPP + 'n7AAc'). On day 14 of gestation (GD), RUPP surgery was performed; 'n7AAc' peptide (2 µg/μL) was administered by miniosmotic pumps in a subset of RUPP rats; and on GD19, sera, placentas, and kidneys were collected. mitochondrial respiration and mtROS were measured in isolated mitochondria using the Oxygraph 2K and fluorescent microplate reader, respectively. Placental and renal mitochondrial respiration and mtROS were improved in RUPP + 'n7AAc' rats compared with RUPP controls. Moreover, endothelial cells (human umbilical vein endothelial cells) treated with RUPP + 'n7AAc' sera exhibited less mtROS compared with those treated with RUPP sera. Overall, our findings suggest that AT1-AA signaling is one stimulus of mtROS during PE.

Abstract P1110: Tumor Necrosis Factor Alpha Blockade Improves Natural Killer Cell Activation, Hypertension, and Mitochondrial Oxidative Stress in a Preclinical Rat Model of Preeclampsia

Preeclamptic (PE) women have placental ischemia, hypertension (HTN), mitochondrial (mt) dysfunction, increased mt-reactive oxygen species (ROS), cytolytic natural killer (NK) cells, and pro-inflammatory cytokines, such as tumor necrosis factor (TNFα). The reduced uterine perfusion pressure (RUPP) preclinical rat model of PE, is a well-established model to study mechanisms of hypertension in response to placental ischemia during pregnancy. Previous studies from our lab have shown that TNFα is elevated in RUPP rats and that blockade of TNFα, via etanercept (ETAN) decreases TNFα and HTN. However, the effect of TNFα blockade on NK cell activation, mt protein/function, and mtROS is unknown. We hypothesized that ETAN would decrease blood pressure, NK cell activation, mtROS, and improve mt function in RUPP rats. Rats were divided into 4 groups: normal pregnant (NP) (n=41), RUPP (n=34), RUPP+low dose (LD) ETAN (0.4 mg/kg) (n=11), RUPP+high dose (HD) ETAN (0.8 mg/kg) (n=19). LD was used previously, while HD is clinically used to treat chronic inflammatory diseases. Gestational day 14, RUPP surgery was performed and ETAN administered subcutaneous on day 18. Day 19, conscious blood pressure (MAP), blood and tissues were collected, and mt were isolated. Flow cytometry was used for quantification of NK cells. MAP was elevated in RUPP vs. NP (119 ± 1 vs. 102± 1 mmHg, p&lt;0.05) which was reduced to 110 ± 2 in RUPP + LD ETAN (p&lt;0.05 vs. RUPP) and 116 ± 1 in RUPP + HD ETAN. Activated NK cells were increased in circulation (5.9 ± 1.8 vs. 4.0 ± 1.4 %), placenta (4.8 ± 1.3 vs. 1.9 ± 0.7 %), and kidneys (3.1 ± 0.5 vs. 0.8 ± 0.5%) of RUPP vs. NP (p&lt;0.05). Both LD (2.1 ± 0.7%, 1.7 ± 0.7%, 0.8 ± 0.5%) and HD (0.2 ± 0.1%, 0.4 ± 0.1%, 0.8 ± 0.2%) ETAN decreased activated NK cells in circulation, placenta, and kidney respectively (p&lt;0.05 vs RUPP). Placental (0.79± 0.02 vs 1±0.05 fold) and renal (0.67± 0.05 vs 1±0.06 fold) mtROS was reduced with LD ETAN vs RUPP (p&lt;0.05). ETAN treatment lowers blood pressure and reduces circulating, placental, and renal activated NK cells and mtROS in placental ischemic rats. Therefore ETAN could be a potential therapeutic for improving HTN, inflammation, and mitochondrial function during complicated pregnancies. Supported: AHA18CDA34110264, HL130456, R01HD067541, &amp; P20GM121334