Janae Moseley

Administration of Interleukin-17 Soluble Receptor C Suppresses TH17 Cells, Oxidative Stress, and Hypertension in Response to Placental Ischemia During Pregnancy

Preeclampsia, new onset hypertension with proteinuria during pregnancy, is associated with chronic inflammation and placental oxidative stress (ROS). Chronic interleukin-17 (IL-17) increases blood pressure, autoantibodies (angiotensin II type I receptor [AT1-AA]), and ROS during pregnancy. The objective of this study was to determine whether T-helper 17 (TH17) suppression via IL-17 recombinant receptor C (IL-17RC) decreases pathophysiology associated with placental ischemia (reduced uterine perfusion pressure [RUPP]). On gestation day 14, miniosmotic pumps infusing 100 pg of IL-17RC per day were implanted into pregnant rats undergoing RUPP. On gestation day 18, carotid catheters were inserted. On gestation day 19, mean arterial pressure was recorded and TH17 cells, oxidative stress, and AT1-AA were measured and analyzed via 1-way ANOVA. Mean arterial pressure increased from 101±2 mm Hg in normal pregnant rats (n=19) to 120±1 mm Hg in RUPP rats (n=17) but decreased to 110±2 mm Hg in RUPP+IL-17RC rats (n=22). Pup weight decreased from 2.28±0.2 g in normal pregnant rats to 1.96±0.3 g in RUPP rats but was significantly increased to 2.01±0.1 in RUPP+IL-17RC rats. TH17 cells were 1.77% in RUPP rats but decreased to 0.65% in RUPP+IL-17RC rats. Urinary isoprostanes were normalized in RUPP+IL-17RC rats (52 pg/µg) compared with 89 pg/µg in RUPP controls. Placental ROS was 652 relative light units in RUPP rats but decreased to 337 relative light units in RUPP+IL-17RC rats. AT1-AA was 17.27±0.7 bpm in RUPP rats but decreased to 5.00±0.5 bpm in RUPP+IL-17RC rats. With this study, we show that infusion of IL-17RC blunts TH17s, oxidative stress, AT1-AA, and hypertension in the RUPP model of preeclampsia, indicating that TH17 cells may play an important role in disease pathophysiology.

Activating autoantibodies to the angiotensin II type I receptor play an important role in mediating hypertension in response to adoptive transfer of CD4+ T lymphocytes from placental ischemic rats.

Hypertension in rats with chronic placental ischemia (reduced uterine perfusion pressure, RUPP) is associated with elevated inflammatory cytokines, agonistic autoantibodies to the angiotensin II type I receptor (AT1-AA) and CD4(+) T cells; all of which are elevated in preclamptic women. Additionally, we have shown that adoptive transfer of RUPP CD4(+) T cells increases blood pressure, inflammatory cytokines, and sFlt-1. The objective of this study was to determine the long-term effects of RUPP CD4(+) T cells on AT1-AA, renal and systemic hemodynamics in pregnant rats. To answer this question CD4(+) T splenocytes were magnetically isolated on day 19 of gestation from control RUPP and normal pregnant (NP) rats and injected into a new group of NP rats at day 13 of gestation. On day 19 of gestation mean arterial pressure (MAP) and renal function (glomerular filtration rates, GFR) were analyzed and serum collected for AT1-AA analysis. To determine a role for AT1-AA to mediate RUPP CD4(+) T cell-induced blood pressure increases, MAP was analyzed in a second group of rats treated with AT1 receptor blockade losartan (10 mg·kg(-1)·day(-1)) and in a third group of rats treated with rituximab, a B cell-depleting agent (250 mg/kg) we have shown previously to decrease AT1-AA production in RUPP rats. MAP increased from 101 ± 2 mmHg NP to 126 ± 2 mmHg in RUPP rats (P < 0.001) and to 123 ± 1 mmHg in NP rats injected with RUPP CD4(+) T cells (NP+RUPP CD4(+)T cells) (P < 0.001). Furthermore, GFR decreased from 2.2 ml/min (n = 7) in NP rats to 1.0 ml/min (n = 5) NP+RUPP CD4(+)T cell. Circulating AT1-AA increased from 0.22 ± 0.1 units in NP rats to 13 ± 0.7 (P < 0.001) units in NP+RUPP CD4(+)T cell-treated rats but decreased to 8.34 ± 1 beats/min in NP+RUPP CD4(+) T cells chronically treated with rituximab. Hypertension in NP+RUPP CD4(+)T cell group was attenuated by losartan (102 ± 4 mmHg) and with B cell depletion (101 ± 5 mmHg). Therefore, we conclude that one mechanism of hypertension in response to CD4(+) T lymphocytes activated during placental ischemia is via AT1 receptor activation, potentially via AT1-AA during pregnancy.

Endothelin-1, Oxidative Stress, and Endogenous Angiotensin II Mechanisms of Angiotensin II Type I Receptor Autoantibody–Enhanced Renal and Blood Pressure Response During Pregnancy

Hypertension during preeclampsia is associated with increased maternal vascular sensitivity to angiotensin II (ANGII). This study was designed to determine mechanisms whereby agonistic autoantibodies to the ANGII type I receptor (AT1-AA) enhance blood pressure (mean arterial pressure [MAP]) and renal vascular sensitivity to ANGII during pregnancy. First, we examined MAP and renal artery resistance index in response to chronic administration of ANGII or AT1-AA or AT1-AA+ANGII in pregnant rats compared with control pregnant rats. To examine mechanisms of heightened sensitivity in response to AT1-AA during pregnancy, we examined the role of endogenous ANGII in AT1-AA–infused pregnant rats, and that of endothelin-1 and oxidative stress in AT1-AA+ANGII–treated rats. Chronic ANGII increased MAP from 95±2 in normal pregnant rats to 115±2 mm Hg; chronic AT1-AA increased MAP to 118±1 mm Hg in normal pregnant rats, which further increased to 123±2 mm Hg with AT1-AA+ANGII. Increasing ANGII from 10−11 to 10−8 decreased afferent arteriole diameter from 15% to 20% but sharply decreased afferent arteriole diameter to 60% in AT1-AA–pretreated vessels. Renal artery resistance index increased from 0.67 in normal pregnant rats to 0.70 with AT1-AA infusion, which was exacerbated to 0.74 in AT1-AA+ANGII–infused rats. AT1-AA–induced hypertension decreased with enalapril but was not attenuated. Both tissue endothelin-1 and reactive oxygen species increased with AT1-AA+ANGII compared with AT1-AA alone, and blockade of either of these pathways had significant effects on MAP or renal artery resistance index. These data support the hypothesis that AT1-AA, via activation of endothelin-1 and oxidative stress and interaction with endogenous ANGII, is an important mechanism whereby MAP and renal vascular responses are enhanced during preeclampsia. # Novelty and Significance {#article-title-24}Hypertension during preeclampsia is associated with increased maternal vascular sensitivity to angiotensin II (ANGII). This study was designed to determine mechanisms whereby agonistic autoantibodies to the ANGII type I receptor (AT1-AA) enhance blood pressure (mean arterial pressure [MAP]) and renal vascular sensitivity to ANGII during pregnancy. First, we examined MAP and renal artery resistance index in response to chronic administration of ANGII or AT1-AA or AT1-AA+ANGII in pregnant rats compared with control pregnant rats. To examine mechanisms of heightened sensitivity in response to AT1-AA during pregnancy, we examined the role of endogenous ANGII in AT1-AA–infused pregnant rats, and that of endothelin-1 and oxidative stress in AT1-AA+ANGII–treated rats. Chronic ANGII increased MAP from 95±2 in normal pregnant rats to 115±2 mm Hg; chronic AT1-AA increased MAP to 118±1 mm Hg in normal pregnant rats, which further increased to 123±2 mm Hg with AT1-AA+ANGII. Increasing ANGII from 10−11 to 10−8 decreased afferent arteriole diameter from 15% to 20% but sharply decreased afferent arteriole diameter to 60% in AT1-AA–pretreated vessels. Renal artery resistance index increased from 0.67 in normal pregnant rats to 0.70 with AT1-AA infusion, which was exacerbated to 0.74 in AT1-AA+ANGII–infused rats. AT1-AA–induced hypertension decreased with enalapril but was not attenuated. Both tissue endothelin-1 and reactive oxygen species increased with AT1-AA+ANGII compared with AT1-AA alone, and blockade of either of these pathways had significant effects on MAP or renal artery resistance index. These data support the hypothesis that AT1-AA, via activation of endothelin-1 and oxidative stress and interaction with endogenous ANGII, is an important mechanism whereby MAP and renal vascular responses are enhanced during preeclampsia.

Magnesium Sulfate Treatment Reverses Seizure Susceptibility and Decreases Neuroinflammation in a Rat Model of Severe Preeclampsia

Eclampsia, defined as unexplained seizure in a woman with preeclampsia, is a life-threatening complication of pregnancy with unclear etiology. Magnesium sulfate (MgSO4) is the leading eclamptic seizure prophylactic, yet its mechanism of action remains unclear. Here, we hypothesized severe preeclampsia is a state of increased seizure susceptibility due to blood-brain barrier (BBB) disruption and neuroinflammation that lowers seizure threshold. Further, MgSO4 decreases seizure susceptibility by protecting the BBB and preventing neuroinflammation. To model severe preeclampsia, placental ischemia (reduced uteroplacental perfusion pressure; RUPP) was combined with a high cholesterol diet (HC) to cause maternal endothelial dysfunction. RUPP+HC rats developed symptoms associated with severe preeclampsia, including hypertension, oxidative stress, endothelial dysfunction and fetal and placental growth restriction. Seizure threshold was determined by quantifying the amount of pentylenetetrazole (PTZ; mg/kg) required to elicit seizure in RUPP+HC±MgSO4 and compared to normal pregnant controls (n = 6/group; gestational day 20). RUPP+HC rats were more sensitive to PTZ with seizure threshold being ∼65% lower vs. control (12.4±1.7 vs. 36.7±3.9 mg/kg PTZ; p<0.05) that was reversed by MgSO4 (45.7±8.7 mg/kg PTZ; p<0.05 vs. RUPP+HC). BBB permeability to sodium fluorescein, measured in-vivo (n = 5–7/group), was increased in RUPP+HC vs. control rats, with more tracer passing into the brain (15.9±1.0 vs. 12.2±0.3 counts/gram ×1000; p<0.05) and was unaffected by MgSO4 (15.6±1.0 counts/gram ×1000; p<0.05 vs. controls). In addition, RUPP+HC rats were in a state of neuroinflammation, indicated by 35±2% of microglia being active compared to 9±2% in normal pregnancy (p<0.01; n = 3–8/group). MgSO4 treatment reversed neuroinflammation, reducing microglial activation to 6±2% (p<0.01 vs. RUPP+HC). Overall, RUPP+HC rats were in a state of augmented seizure susceptibility potentially due to increased BBB permeability and neuroinflammation. MgSO4 treatment reversed this, increasing seizure threshold and decreasing neuroinflammation, without affecting BBB permeability. Thus, reducing neuroinflammation may be one mechanism by which MgSO4 prevents eclampsia during severe preeclampsia.

Hypertension in response to CD4+ T cells from reduced uterine perfusion pregnant rats is associated with activation of the endothelin-1 system

We have shown that adoptive transfer of CD4(+) T cells from placental ischemia (reduction in uteroplacental perfusion, RUPP) rats causes hypertension and elevated inflammatory cytokines during pregnancy. In this study we tested the hypothesis that adoptive transfer of RUPP CD4(+) T cells was associated with endothelin-1 activation as a mechanism to increase blood pressure during pregnancy. CD4(+) T cells from RUPP or normal pregnant (NP) rats were adoptively transferred into NP rats on gestational day 13. Mean arterial pressure (MAP) was analyzed on gestational day 19, and tissues were collected for endothelin-1 analysis. MAP increased in placental ischemic RUPP rats versus NP rats (124.1 ± 3 vs. 96.2 ± 3 mmHg; P = 0.0001) and increased in NP recipients of RUPP CD4(+) T cells (117.8 ± 2 mmHg; P = 0.001 compared with NP). Adoptive transfer of RUPP CD4(+) T cells increased placental preproendothelin-1 mRNA 2.1-fold compared with NP CD4(+) T cell rats and 1.7-fold compared with NP. Endothelin-1 secretion from endothelial cells exposed to NP rat serum was 52.2 ± 1.9 pg·mg(-1)·ml(-1), 77.5 ± 4.3 pg·mg(-1)·ml(-1) with RUPP rat serum (P = 0.0003); 47.2 ± .16 pg·mg(-1)·ml(-1) with NP+NP CD4(+) T cell serum, and 62.2 ± 2.1 pg·mg(-1)·ml(-1) with NP+RUPP CD4(+) T cell serum (P = 0.002). To test the role of endothelin-1 in RUPP CD4(+) T cell-induced hypertension, pregnant rats were treated with an endothelin A (ET(A)) receptor antagonist (ABT-627, 5 mg/kg) via drinking water. MAP was 92 ± 2 mmHg in NP+ET(A) blockade and 108 ± 3 mmHg in RUPP+ET(A) blockade; 95 ± 5 mmHg in NP+NP CD4(+) T cells+ET(A) blockade and 102 ± 2 mmHg in NP+RUPP CD4(+) T cells+ET(A) blockade. These data indicate the importance of endothelin-1 activation to cause hypertension via chronic exposure to activated CD4(+) T cells in response to placental ischemia.

An increased population of regulatory T cells improves the pathophysiology of placental ischemia in a rat model of preeclampsia

The reduced uterine perfusion pressure (RUPP) rat model of preeclampsia exhibits much of the pathology characterizing this disease, such as hypertension, inflammation, suppressed regulatory T cells (TRegs), reactive oxygen species (ROS), and autoantibodies to the ANG II type I receptor (AT1-AA) during pregnancy. The objective of this study was to determine whether supplementation of normal pregnant (NP) TRegs into RUPP rats would attenuate the pathophysiology associated with preeclampsia during pregnancy. CD4(+)/CD25(+) T cells were isolated from spleens of NP and RUPP rats, cultured, and injected into gestation day (GD) 12 normal pregnant rats that underwent the RUPP procedure on GD 14. On GD 1, mean arterial pressure (MAP) was recorded, and blood and tissues were collected for analysis. One-way ANOVA was used for statistical analysis. MAP increased from 99 ± 2 mmHg in NP (n = 12) to 127 ± 2 mmHg in RUPP (n = 21) but decreased to 118 ± 2 mmHg in RUPP+NP TRegs (n = 17). Circulating IL-6 and IL-10 were not significantly changed, while circulating TNF-α and IL-17 were significantly decreased after supplementation of TRegs. Placental and renal ROS were 339 ± 58.7 and 603 ± 88.1 RLU·min(-1)·mg(-1) in RUPP and significantly decreased to 178 ± 27.8 and 171 ± 55.6 RLU·min(-1)·mg(-1), respectively, in RUPP+NP TRegs; AT1-AA was 17.81 ± 1.1 beats per minute (bpm) in RUPP but was attenuated to 0.50 ± 0.3 bpm with NP TRegs. This study demonstrates that NP TRegs can significantly improve inflammatory mediators, such as IL-17, TNF-α, and AT1-AA, which have been shown to increase blood pressure during pregnancy.

IL-10 supplementation increases Tregs and decreases hypertension in the RUPP rat model of preeclampsia

Objective: The reduced uterine perfusion pressure (RUPP) rat model of preeclampsia was used to determine the effects of added interleukin-10 (IL-10) on Tregs and hypertension in response to placental ischemia and how the decrease in these anti-inflammatory factors mediates the pathophysiology of preeclampsia. Methods: IL-10 (2.5 ng/kg/d) was infused via osmotic mini-pump implanted intraperitoneally on day 14 of gestation and, at the same time, the RUPP procedure was performed. Results: IL-10 reduced mean arterial pressure (p < 0.001), decreased CD4+ T cells (p = 0.044), while increasing Tregs (p = 0.043) which led to lower IL-6 and TNF-α (p = 0.008 and p = 0.003), reduced AT1-AA production (p < 0.001), and decreased oxidative stress (p = 0.029) in RUPP rats. Conclusion: These data indicate that IL-10 supplementation increases Tregs and helps to balance the altered immune system seen during preeclampsia.

17-Hydroxyprogesterone Caproate Significantly Improves Clinical Characteristics of Preeclampsia in the Reduced Uterine Perfusion Pressure Rat Model

Preeclampsia is characterized by increased uterine artery resistance index, chronic immune activation, and decreased circulating nitric oxide levels. 17-&agr;-Hydroxyprogesterone caproate (17-OHPC) is a synthetic metabolite of progesterone used for the prevention of recurrent preterm birth. We hypothesized that 17-OHPC could reduce mean arterial pressure by decreasing inflammation, whereas improving vasodilation by increasing nitric oxide bioavailability and uterine artery resistance index during late gestation in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. 17-OHPC (3.32 mg/kg) was intraperitoneally administered on gestation day 18 into RUPP rats, carotid catheters inserted, and mean arterial pressure, blood, and tissues were collected on day 19. Mean arterial pressure in normal pregnant (NP; n=13) was 92±2.0 and increased to123±2.0 in RUPP (n=18; P<0.0001), which was improved to 116±1.5 mm Hg in RUPP+17-OHPC (n=10; 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; P<0.05) but was reduced to 2.72%±0.87% (n=14; P<0.05) in RUPP+17-OHPC. Circulating nitrate/nitrite was 26.34±3.5 µmol/L in NP (n=12) but was reduced to14.58±3.1 in RUPP rats (n=8; P=0.03) and increased to 22.69±1.62 in RUPP+17-OHPC (n=7; P=0.05). Endothelial nitric oxide synthase expression was 0.65±0.11 AU in NP (n=4), which decreased to 0.33±0.01 in RUPP rats (n=4; P=0.05) but increased to 0.57±0.01 in RUPP+17-OHPC (n=5; P=0.03). Uterine artery resistance index was 0.54±0.02 in NP (n=3), 0.78±0.03 in RUPP (n=4), and 0.63±0.038 in RUPP+17-OHPC (n=8; both P<0.05). Our findings demonstrate that even though modest, lowering blood pressure with 17-OHPC could be a viable treatment option for suppressing inflammation, uterine artery vasoconstriction while improving litter size.

CD4+ T Cells Are Important Mediators of Oxidative Stress That Cause Hypertension in Response to Placental Ischemia

Preeclampsia is associated with oxidative stress, which is suspected to play a role in hypertension, placental ischemia, and fetal demise associated with the disease. Various cellular sources of oxidative stress, such as neutrophils, monocytes, and CD4+ T cells have been suggested as culprits in the pathophysiology of preeclampsia. The objective of this study was to examine a role of circulating and placental CD4+ T cells in oxidative stress in response to placental ischemia during pregnancy. CD4+ T cells and oxidative stress were measured in preeclamptic and normal pregnant women, placental ischemic and normal pregnant rats, and normal pregnant recipient rats of placental ischemic CD4+ T cells. Women with preeclampsia had significantly increased circulating (P=0.02) and placental CD4+ T cells (P=0.0001); lymphocyte secretion of myeloperoxidase (P=0.004); and placental reactive oxygen species (P=0.0004) when compared with normal pregnant women. CD4+ T cells from placental ischemic rats cause many facets of preeclampsia when injected into normal pregnant recipient rats on gestational day 13. On gestational day 19, blood pressure increased in normal pregnant recipients of placental ischemic CD4+ T cells (P=0.002) compared with that in normal pregnant rats. Similar to preeclamptic patients, CD4+ T cells from placental ischemic rats secreted significantly more myeloperoxidase (P=0.003) and induced oxidative stress in cultured vascular cells (P=0.003) than normal pregnant rat CD4+Tcells. Apocynin, a nicotinamide adenine dinucleotide phosphate inhibitor, attenuated hypertension and all oxidative stress markers in placental ischemic and normal pregnant recipient rats of placental ischemic CD4+Tcells (P=0.05). These data demonstrate an important role for CD4+ T cells in mediating another factor, oxidative stress, to cause hypertension during preeclampsia.

CD4+ T Cells Play a Critical Role in Mediating Hypertension in Response to Placental Ischemia

Similar to preeclamptic women, hypertension in the chronic Reduced Uterine Perfusion Pressure Rat Model Of Preeclampsia (RUPP) is associated with increased CD4+ T cells, cytokines, sFlt-1 and agonistic autoantibodies to the AngII receptor (AT1-AA). We examined the effect inhibition of T cell co-stimulation in RUPP rats treated with (A) (abatacept, 250 mg/kg, infused i.v. at gestation day 13), on hypertension and sFlt-1, TNF-α and AT1-AA. RUPP surgical procedure was performed on day 14. On day 19 MAP increased from 94+2 mmHg in Normal Pregnant (NP) to 123 ± 3 mmHg in RUPP control rats. This response was attenuated by Abatacept, MAP was 104 ± 2 mmHg in RUPP ± A, and 96 ± 2 mmHg NP ± A. Percent circulating CD4+ T cells were 66 ± 3% in RUPPs compared to 55 ± 3% NP rats (p<0.04) but were normalized in RUPP ± A rats (54 ± 3%). The twofold increase in TNF alpha seen in RUPPs (277 ± 47 pg/ml) was decreased to 80 ± 18 pg/ml in RUPP+A. Placental sFlt-1 was reduced 70 % to 151 ± 28 in RUPP ± A compared 488 ± 61 pg/ml in RUPP (p<0.001). AT1-AA decreased from 20 ± 0.8 bpm in control RUPP to 6 ± 0.7 bpm in RUPP ± A. We next determined the effect of RUPP in causing hypertension in pregnant T cell deficient rats by examining MAP in NP (123 ± 5 mmHg) and RUPP athymic nude rats (123 ± 7 mmHg). In the absence of T cells, hypertension in response to placental ischemia was completely abolished. Collectively these data indicate that CD4+ Tcells in response to placental ischemia play an important role in the pathophysiology of hypertension associated with preeclampsia.