Hypertension Editors' Picks: Preeclampsia, Pregnancy, and Hypertension.

Preeclampsia (PE), a disorder of new‐onset maternal hypertension and vascular dysfunction during pregnancy, is thought to be linked to placental ischemia‐induced release of prohypertensive factors and reductions of vasoprotective factors in the maternal circulation. Although markers of sympathetic nervous activity are elevated in experimental models of placental ischemia‐induced hypertension and women with PE compared with their normal pregnant counterparts, the importance of adrenergic receptor signaling in the development of hypertension in PE is unknown. Therefore, we tested the hypothesis that adrenergic receptor blockade attenuates the development of placental ischemia‐induced hypertension in rats. Wistar Hannover rats underwent reduced uterine perfusion pressure (RUPP) or Sham surgeries on gestational day 14. By day 19, mean arterial blood pressure (MAP) was increased in RUPP over Sham rats. Groups of RUPP and Sham pregnant rats received terazosin and propranolol (3 mg/kg per day of each via subcutaneous osmotic minipump) to block α 1‐ and β‐adrenergic receptors, respectively, beginning on gestational day 14. Adrenergic blockade significantly attenuated the development of hypertension in the RUPP rats with a slight blood pressure‐lowering response in the Sham, normal pregnant rats by day 19. In conclusion, these data implicate that placental ischemia‐induced hypertension involves adrenergic receptor signaling to promote increases in blood pressure during PE.

Preeclampsia (PE), new onset hypertension in response to placental ischemia during pregnancy, is associated with chronic inflammation characterized by elevated tumor necrosis factor (TNF-α), interleukin-6 (IL-6), agonistic autoantibody to the Ang II type 1 receptor (AT1-AA). In addition, evidence for a shift towards proinflammatory CD4+TH1 vs CD4+TH2 profile exist in PE. Therefore we tested the hypothesis that IL-4, a cytokine essential for TH2 differentiation and proliferation, would improve pregnancy outcomes in response to placental ischemia (RUPP) by shifting the immune profile toward CD4+TH2. Interleukin-4, 600 ng/day, was administered via a mini-osmotic pump on day 14 of gestation into normal pregnant (NP) rats and into RUPP rats immediately following the reduced uterine perfusion pressure (RUPP) procedure and carotid catheters were inserted on gestation day 18. Blood pressure (MAP), TNF-α, IL-6, AT1-AA and circulating TH2 cells were measured on GD 19. MAP in NP rats (n=10) was 96 + 2, 101 + 2 in NP+IL-4 rats (n=14), 130 + 4 in RUPP rats (n=6), which improved to 108 + 2 mmHg in RUPP+IL-4 rats (n=15), p< 0.05. Plasma levels of TNF-α and IL-6 were 25 + 6, 29 + 3 in NP rats (n=7-8/group), 116 + 30, 224 + 62 in RUPP rats (n=9-10/group), which decreased to 23 + 5 and 135 + 48 pg/mL in RUPP+IL-4 rats (n=5-7/group), p<0.05. Importantly, plasma levels of AT1-AA were 0.3 + 0.4 in NP rats (n=8), 0.3 + 0.2 in NP+IL-4 rats (n=5), 18 + 0.3 in RUPP rats (n=9), which were blunted to 4 + 1 bpm in RUPP+IL-4 rats (n=14), p<0.05. Circulating TH2 cells were 17.3 ± 2.7 in NP rats (n=3), 9.0 ± 2.0 in RUPP rats (n=5), which improved to 13.4 ± 3.2 % gated in RUPP+IL-4 rats (n=9). This study illustrates that administration of IL-4 decreases TNF-α, IL-6, AT1-AA, possibly by increasing TH2/IL-4 in RUPP rats, which ultimately led to a reduction in hypertension in response to placental ischemia of pregnancy.

Preeclampsia (PE), new onset hypertension at 20 weeks of gestation, is characterized by increased uterine artery resistance index (UARI), chronic immune activation and decreased of vasodilators such as nitric oxide (NO). Despite being one of the leading causes of death in pregnant women, currently there is no effective treatment for PE except for early delivery of the fetus. We have demonstrated that PE women have significantly lower circulating progesterone than normal pregnant (NP). 17-alpha-hydroxyprogesterone caproate (17-OHPC) is a synthetic metabolite of progesterone used for the prevention of recurrent preterm birth and although the mechanism is not understood, is suspected to have vasodilatory and anti-inflammatory effects. Therefore, we hypothesized that progesterone (17-OHPC) supplementation could reduce blood pressure (MAP), pro-inflammatory cytokines, CD4+ T cells, UARI, as well as increase NO bioavailability in a hypertensive rat model of PE. To address this question 17-OHPC (3.32mg/kg) was intraperitoneally administered on day 18 of gestation into Reduced Uterine Perfusion Pressure (RUPP) rats and carotid catheters were inserted. MAP, blood and tissues were collected on day 19. MAP in NP rats (n=13) was 92±2; 123±2 in RUPP (n=18), and 116 ±1 mmHg in RUPP+17-OHPC (n=10), p <0.05. UARI was 0.78±0.03 in RUPP (n=4) and 0.63±0.038 in RUPP+17-OHPC (n=8), p<0.05. Circulating CD4+ T cells were 1.19±1.0% of gated cells in NP (n=7), which increased to 8.52±2.4% in RUPP rats (n=10) but was significantly reduced to 2.72±0.87% (n=14) in RUPP + 17 O-HPC, p <0.05. Total circulating nitrate/nitrite was 26.34 ±3.5 μM in NP (n=12); 14.58±3.1 in RUPP rats (n=8) and increased to 26.69±1.62 in RUPP+17-OHPC (n=7), p <0.05. Aortic eNOS expression was 0.65±0.11 A.U in NP (n=4), which decreased to 0.33±0.01 in RUPP rats (n=4) but increased to 0.57±0.01 in RUPP+17-OHPC (n=5), p <0.05. Levels of TNF-alpha were 65.84±17.7 pg/ml in RUPP rats (n=5) but were blunted to 17.24±3.9 in RUPP+17-OHPC (n=8), p <0.05. In conclusion, 17-OHPC supplementation improves inflammation, UARI, hypertension, and nitric oxide bioavailability in response to placental ischemia during pregnancy and should therefore be considered further for addition to the clinical management of PE

Preeclampsia is characterized by elevated TNF-α (tumor necrosis factor-α), antiangiogenic factors, such as sFlt-1 (soluble vascular endothelial growth factor receptor 1), increased uterine artery resistance index, and decreased of NO during pregnancy. Previously we showed that 17-hydroxyprogesterone caproate (17-OHPC) administered into reduced uterine perfusion pressure (RUPP) rats on day 18 of gestation improved hypertension without improving pup weight. We hypothesized that earlier administration of 17-OHPC on day 15 of gestation could improve pathophysiology of preeclampsia and fetal outcomes in response to placental ischemia. Carotid catheters were inserted on day 18, and mean arterial blood pressure and samples were collected on day 19. Mean arterial blood pressure in normal pregnant rats was 102±2, 105±2 in normal pregnant+day 15 of gestation (GD15) 17-OHPC, 127±2 in RUPP and 112±1 mm Hg in RUPP+GD15 17-OHPC, P<0.05. Pup weight and litter size were improved from 1.9±0.05, 10.1±1.4 in RUPP to 2.1±0.07 g and 13.2±0.6 in RUPP+GD15 17-OHPC, P<0.05. Uterine artery resistance index was 0.8±0.03 in RUPP, which was decreased to 0.6±0.04 in RUPP+GD15 17-OHPC, P<0.05. Plasma TNF-α levels were 164±34 in RUPP and blunted to 29±9 pg/mL in RUPP+GD15 17-OHPC, P<0.05. Plasma nitrate-nitrite levels were 10.8±2.3 in RUPP rats and significantly increased to 25.5±5.2 µmol/L in RUPP+GD15 17-OHPC, P<0.05. sFlt-1 levels were 386±141 in RUPP rats, which were reduced to 110.2±11 in RUPP+17-OHPC, P<0.05. These data indicate that GD15 17-OHPC improves pathophysiology in RUPP rats, possibly via improving sFlt-1 reduced NO during pregnancy.

### Case A 68-year-old right-hand-dominant man was brought to the hospital because of a speech disturbance and right arm and leg weakness. He awoke with these deficits and was last known to be symptom-free when retiring to bed the previous evening 8 hours earlier. His past medical history was notable for coronary heart disease, the patient having underwent coronary artery bypass surgery 7 years previously for unstable angina, but he had no known history of myocardial infarction. He also had hypertension and hyperlipidemia, and smoked 1 pack of cigarettes daily for more than 40 years. He had no history of calf claudication. His hypertension was being treated with a diuretic and β-adrenergic receptor blocker. He was also prescribed 325 mg of aspirin daily and an HMG CoA-reductase inhibitor (statin); however, his wife remarked that he often forgot to take his medications. His last total cholesterol was 240 mg/dL, with LDL cholesterol of 130 mg/dL. He had a strong family history of coronary heart disease after the age of 50. He had no known drug allergies. #### Physical Examination The patient’s blood pressure was 195/100 mm Hg in both arms, with a regular pulse of 90 bpm. His weight was 225 lb (body mass index: 31.4 kg/m2). His lungs were clear to auscultation. Cardiac examination showed a laterally displaced point of maximum impulse with an S4 gallop and a soft nonradiating systolic murmur at the base. His abdomen was obese without organomegaly and no abdominal bruits were detected. He had no rashes and no joint deformities. The left superficial temporal artery pulse was stronger than the right. There were soft bilateral anterior cervical bruits, left louder than right, but no supraclavicular bruits. There were bilateral femoral bruits. Radial pulses were 2+ and symmetric. Dorsalis pedis and posterior tibial pulses were 1+. …

T-helper (TH)17s, IL-17, and cytolytic natural killer cells (cNKs) are increased in preeclampsia and contribute to the hypertension, inflammation, and fetal growth restriction that occurs in response to placental ischemia in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. As IL-17 stimulates NK cytotoxicity in vitro, we tested the hypothesis that IL-17 inhibition in RUPP rats would decrease cNK activation as a mechanism to improve maternal and fetal outcomes. On gestation day (GD) 14, rats undergoing RUPP received a miniosmotic pump infusing IL-17RC (100 pg/day), a soluble IL-17 receptor (RUPP + IL-17RC). On GD19, mean arterial pressure (MAP) was measured in normal pregnant (NP), RUPP, and RUPP + IL-17RC rats (n = 10-12/group), animals were euthanized, and blood and tissues were collected for analysis. MAP was 30% higher in RUPP compared with NP (P < 0.0001) and was 12% lower in RUPP + IL-17RC (P = 0.0007 vs. RUPP). Placental cytolytic NK cells were 132% higher in RUPP than in NP (P = 0.04 vs. NP) and were normalized in RUPP + IL-17RC (P = 0.03 vs. RUPP). Placental levels of TNF-α, a cNK-secreted cytokine, and macrophage inflammatory protein-3α (MIP-3α), a cNK chemokine, were higher in RUPP vs. NP and lower after IL-17 blockade. Placental VEGF was lower in RUPP vs. NP and was normalized in RUPP + IL-17RC. In vitro cytolytic activity of RUPP placental NKs was higher compared with NP and was blunted in RUPP + IL-17RC NKs. Finally, both fetal weight and placental weight were lower in RUPP compared with NP, and were improved in RUPP + IL-17RC. These data identify IL-17 as a mediator of cNK activation in response to placental ischemia during pregnancy.

Two important clinical features of preeclampsia (PE) are hypertension and fetal growth restriction. The reduced uterine perfusion pressure (RUPP) preclinical rat model of PE exhibits both of these features. Moreover, RUPP and PE women have elevated vasoconstrictor peptide endothelin-1 (ET-1) and inflammation. Interleukin-2 (IL-2) is a cytokine that regulates NK cell activity and is elevated in miscarriage, PE, and RUPP rats. The objective of this study was to examine a role for IL-2 in NK cell activation, fetal growth restriction, and hypertension during pregnancy by either infusion of IL-2 or blockade of IL-2 (basiliximab) in normal pregnant (NP) and RUPP rats. On gestational day 14, NP and RUPP rats received low (LD), middle (MD), or high dose (HD) IL-2 (0.05, 0.10, or 0.20 ng/ml) IP or basiliximab (0.07 mg per rat) by IV infusion. On day 19, blood pressure (MAP), pup weights, and blood were collected. Basiliximab had no effect on blood pressure, however, significantly lowered NK cells and may have worsened overall fetal survival in RUPP rats. However, IL-2 LD (102 ± 4 mmHg) and IL-2 HD (105 ± 6 mmHg) significantly lowered blood pressure, ET-1, and activated NK cells compared to control RUPPs (124 ± 3 mmHg, p < 0.05). Importantly, IL-2 in RUPP rats significantly reduced fetal weight and survival. These data indicate that although maternal benefits may have occurred with low dose IL-2 infusion, negative effects were seen in the fetus. Moreover, inhibition of IL-2 signaling did not have favorable outcome for the mother or fetus.

Blood–Brain Barrier Breakdown in Reduced Uterine Perfusion Pressure: A Possible Model of Posterior Reversible Encephalopathy Syndrome

We have shown that hypertension in response to chronic placental ischemia is associated with elevated inflammatory cytokines and CD4(+) T cells. However, it is unknown whether these cells play an important role in mediating hypertension in response to placental ischemia. Therefore, we hypothesize that reduced uterine perfusion pressure (RUPP)-induced CD4(+) T cells increase blood pressure during pregnancy. To answer this question, CD4(+) T cells were isolated from spleens at day 19 of gestation from control normal pregnant (NP) and pregnant RUPP rats, cultured, and adjusted to 10(6) cells per 100 μL of saline for intraperitoneal injection into NP rats at day 13 of gestation. On day 18, in the experimental groups of rats, arterial catheters were inserted, and on day 19 mean arterial pressure was analyzed. Inflammatory cytokines and antiangiogenic factor soluble fms-like tyrosine kinase 1 were determined via ELISA. Mean arterial pressure increased from 104±2 mm Hg in NP rats to 124±2 mm Hg in RUPP rats (P<0.001) and to 118±1 mm Hg in rats receiving RUPP CD4(+) T cells (P<0.001). Circulating tumor necrosis factor-α and soluble fms-like tyrosine kinase 1 were elevated in recipients of RUPP CD4(+) T cells to levels similar to control RUPP rats. In contrast, virgin rats injected with NP or RUPP CD4(+) T cells exhibited no blood pressure changes compared with control virgin rats. Importantly, mean arterial pressure did not change in recipients of NP CD4(+) T cells (109±3 mm Hg). These data support the hypothesis that RUPP-induced CD4(+) T cells play an important role in the pathophysiology of hypertension in response to placental ischemia.

Tumor Necrosis Factor-alpha Blockade Improves Uterine Artery Resistance, Maternal Blood Pressure, and Fetal Growth in Placental Ischemic Rats.

Preeclampsia (PE), new onset hypertension during pregnancy, is associated with inflammation and B cells secreting agonistic autoantibodies against the angiotensin II type 1 receptor (AT1-AA). Two recognized subsets of B Cells are B1 and B2 B Cells. B2 B Cells are involved in adaptive immune responses and produce specific antibodies. B1 B Cells produce natural antibodies and are implicated in the pathophysiology of PE through AT1-AA. The Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia recapitulates many characteristics of PE. We have previously shown that either B cell depletion or AT1-AA epitope binding protein (7AA) in RUPP rats improved hypertension. It is currently unknown which B cell subsets make the AT1AA in PE. This information would add to the design of new therapies targeting one B cell type for depletion. Therefore, we hypothesize that B cells and specifically B2 cells cause hypertension and NK cell activation during pregnancy through production of the AT1-AA. To test this hypothesis, total splenic B Cells and B2 cells were isolated from RUPP rats on Gestation Day (GD)19 RUPP and adoptively transferred into NP rats on GD12, blood pressure (MAP), placental and circulating cNKs were measured by flow cytometry on GD19. To test the role of AT1-AA in the hypertension, 7AA was administered to a group of recipient rats on GD14. MAP increased in NP+RUPP B cells to 116 ± 3 mmHg, n=11, and to 112 mmHg ± 2, n=12, in NP+RUPP B2 cells, compared to NP rats(p&lt;0.001). Administration of 7AA attenuated hypertension in response to total RUPP B cells (99 mmHg ± 6, n=5)(p&lt;0.01) and in response to RUPP B2s (98 mmHg ± 4, n=6) (p&lt;0.05). Circulating cNKs were elevated in NP+RUPPBcells (6 ± 2.5, n=5)(p&lt;0.01) and in NP+RUPP B2 cells (4.8 ± 1.6, n=11)(p&lt;0.01) compared to NP (0.275 ± 0.2, n=11). Placental cNKs were elevated in NP+RUPPBcells (2.32 ± 0.73, n=6)(p&lt;0.01) and in NP+RUPP B2 cells (1.01 ± 0.2, n=11)(p&lt;0.01) compared to NP (0.225 ± 0.2, n=11). In conclusion total B Cells and B2 B cells activated in response to placental ischemia cause hypertension via secretion of the AT1-AA and NK cell activation during pregnancy and play an important role in PE.

Preeclampsia (PE) is new onset hypertension during pregnancy and is associated with elevated inflammatory response such as CD4+ T cells, NK cells, and cytokines. We have previously shown women with PE exhibit increases in circulating and placental CD4+T cells and placental mitochondrial (mt) dysfunction/ROS compared to normal pregnant (NP) women. The Reduced Uterine Perfusion Pressure (RUPP) rat model produces many characteristics of PE such as hypertension, increases in CD4+ cells, increases in renal and placental NK cells, and mt dysfunction/ROS. We have previously demonstrated that RUPP CD4+T cells cause hypertension in NP rats, however the role of RUPP CD4+ T cells in stimulating NK cells to cause mt dysfunction/ROS are not elucidated. Therefore, we examined the effect of adoptive transfer of RUPP CD4+ T cells to activate NK cells in NP rats. Splenic CD4+ T cells were isolated from RUPP rats, cultured, and injected into NP rats on GD 13. On GD19, MAP values and blood/tissue samples were collected from both RUPP CD4+ T cell recipients and NP controls. Mitochondrial respiration and mtROS were measured in isolated mitochondria using the Oxygraph 2K and fluorescent microplate reader, respectively. A student’s t-test was used for statistical analysis. On GD19, MAP increased to 110±2 mmHg (n=13) in RUPP CD4+ T cell recipients compared to control NP rats 102±2 mmHg (n=7, p&lt;0.05). Circulating cytolytic NK cells increased to 3±0.6% in RUPP CD4+ T cell recipients (n=8) compared to NP controls 0.3±0.2% (n=7, p&lt;0.05). Placental state 3 (209.3±31.3 vs 422.7 ±83.3 pmol/sec/mg, p&lt;0.05) and maximal (152.1±46.2 vs 229.7±58.9 pmol/sec/mg) and renal state 3 (133.4 ±21.4 vs 289.8±43.4 pmol/sec/mg, p&lt;0.05) and maximal (61.8±18 vs 242.4±27.7 pmol/sec/mg, p&lt;0.05) respiration rates, indicative of ATP production and electron transport chain efficacy respectively, were reduced with RUPP CD4+ T cells (n=6; n=9) compared to NP (n=5; n=5). Collectively, the data indicate that the adoptive transfer of RUPP CD4+ T cells stimulates cytolytic NK cells and placental and renal mitochondrial dysfunction/ROS during pregnancy as important mechanisms of hypertension in the pathophysiology of preeclampsia. Keywords: Preeclamspia, Hypertension, Oxidative stress

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.

The Reduced Uterine Perfusion Pressure (RUPP) rat model of placental ischemia recapitulates many characteristics of preeclampsia including maternal hypertension, intrauterine growth restriction (IUGR), and increased cytolytic natural killer cells (cNKs). While we have previously shown a 5-fold higher cytotoxicity of RUPP NKs versus normal pregnant NKs, their role in RUPP pathophysiology remains unclear. In this study, we tested the hypotheses that (1) adoptive transfer of RUPP-stimulated NKs will induce maternal hypertension and IUGR in normal pregnant control (Sham) rats and (2) adoptive transfer of Sham NKs will attenuate maternal hypertension and IUGR in RUPP rats. On gestation day (GD)14, vehicle or 5×106 RUPP NKs were infused i.v. into a subset of Sham rats (Sham+RUPP NK), and vehicle or 5×106 Sham NKs were infused i.v. into a subset of RUPP rats (RUPP+Sham NK; n=12/group). On GD18, Uterine Artery Resistance Index (UARI) was measured. On GD19, mean arterial pressure (MAP) was measured, animals were sacrificed, and blood and tissues were collected for analysis. Adoptive transfer of RUPP NKs into Sham rats resulted in elevated NK activation, UARI, placental oxidative stress, and preproendothelin expression as well as reduced circulating nitrate/nitrite. This led to maternal hypertension and IUGR. RUPP recipients of Sham NKs demonstrated normalized NK activation, sFlt-1, circulating and placental VEGF, and UARI, which led to improved maternal blood pressure and normal fetal growth. These data suggest a direct role for cNKs in causing preeclampsia pathophysiology and a role for normal NKs to improve maternal outcomes and IUGR during late gestation.

Preeclampsia is a pregnancy specific condition characterized by decreased placental perfusion, new onset hypertension, intrauterine growth restriction, decreased free plasma vascular endothelial growth factor (VEGF) and increased innate immune complement system activation producing C3a and C5a. Our previous work demonstrated the importance of complement activation in the reduced uterine perfusion pressure (RUPP) model of placental ischemia‐ induced hypertension in rat. However, the complement activation product important in mediating the hypertension is unclear. Hypothesis: Complement activation product C5a mediates placental ischemia‐induced hypertension independent of changes in free plasma VEGF. On gestation day (GD) 14, rats underwent sham surgery or clip placement on ovarian arteries and inferior abdominal aorta (RUPP) resulting in placental ischemia and increased blood pressure on GD19. The role of C5a was determined by once daily injection of C5a receptor antagonist acetyl‐F‐[Orn‐P‐(D‐Cha)‐WR] (PMX53, 3mg/kg subcutaneous) or vehicle (10% ethanol in saline) on GD14‐18. On GD19, mean arterial pressure (MAP, mmHg) was measured via arterial catheter. Complement activation was monitored by measuring relative serum C3a concentration since C5a was not detectable in serum by current assay methods. VEGF was assessed by ELISA. MAP increased in RUPP (n=23, 108±2) vs. Sham (n=19, 93±2) and PMX53 treatment significantly decreased MAP in RUPP rats (n=11, 101±3) with no effect in Sham (n=5, 93±3). As expected, complement activation increased in RUPP vs Sham (p&lt;0.05). Also, fetal weight and VEGF decreased in RUPP vs Sham (p&lt;0.05). PMX53 treatment did not reverse RUPP‐induced changes in complement activation, fetal weight, or VEGF. These data indicate that C5a in part mediates placental ischemia‐induced hypertension independent of reduced free plasma VEGF.Grant Funding Source: Supported by NIH HL109843