Abstract 052: Placental Growth Factor (PlGF) Reduces Blood Pressure and Improves Endothelin Type B Receptor (ETBR)-Mediated Microvascular Dilation in Hypertensive Pregnant Rats

Preeclampsia is a pregnancy-related hypertensive disorder (HTN-Preg) with an imbalance between anti-angiogenic soluble fms-like tyrosine kinase-1 (sFlt-1) and angiogenic PlGF, but the vascular targets involved are unclear. We have shown downregulation of endothelial ET B R in Preg rats with reduced uterine perfusion pressure (RUPP), and studies have shown increased plasma sFlt-1 in RUPP rats. We tested if raising PIGF/sFlt-1 ratio by infusing PIGF (10 μg/kg/day) in RUPP rats would improve BP and microvascular ET B R signaling, and vice versa, if lowering PIGF/sFlt-1 ratio by infusing sFlt-1 (10 μg/kg/day) in Preg rats increases BP and reduces ET B R signaling. On day 19, BP was recorded and mesenteric microvessels were isolated for measurement of diameter and [Ca 2+ ] i (fura-2 340/380 ratio). BP was in PlGF-RUPP 105±2 < RUPP 126±1 and in sFlt-Preg 125±4 > Norm-Preg 97±5 mmHg. ET-1 vasoconstriction was in PlGF-RUPP 62.6±3.0 < RUPP 83.4±5.3 and in sFlt-Preg 76.1±4.7 > Norm-Preg 52.1±3.2%. ET-1 caused parallel increases in microvascular [Ca 2+ ] i that was in PlGF-RUPP 0.87±0.02 < RUPP 0.92±0.01 and in sFlt-Preg 0.93±0.02 > Norm-Preg 0.85±0.01. Endothelium removal or microvessel treatment with ET B R antagonist BQ-788 enhanced ET-1 vasoconstriction and [Ca 2+ ] i in Norm-Preg and PlGF-RUPP, but not RUPP or sFlt-Preg. The ET B R agonists sarafotoxin 6c (S6c) and IRL-1620 caused relaxation that was in PlGF-RUPP 42.9±10.8, 38.0±11.2% > RUPP 4.7±3.4, 7.5±2.3% and in sFlt-Preg 3.1±1.0, 5.4±1.6% < Norm-Preg 29.9±7.8, 28.0±9.1%. L-NAME partially reduced ACh- and ET B R-induced relaxation in Norm-Preg, PlGF-RUPP, but not RUPP or sFlt-Preg, suggesting that PlGF improves the decreased NO-dependent and ET B R-mediated vasorelaxation in HTN-Preg. Basal, ACh-, S6c-, and IRL-1620-induced nitrate/nitrite production was enhanced in mesenteric arteries of PIGF-RUPP and Norm-Preg vs. RUPP rats. Western blots and immunohistochemistry revealed greater levels of endothelial ET B R in PlGF-RUPP and Norm-Preg vs. RUPP and sFlt-Preg. Thus improving PlGF/sFlt-1 balance reduces BP and ET-1 vasoconstriction, and enhances ET B R-mediated NO-dependent vasodilation in RUPP rats, and could be a new approach in the management of HTN-Preg.

Download Full-text

Increased Myogenic Responses of Resistance-Sized Mesenteric Arteries After Reduced Uterine Perfusion Pressure in Pregnant Rats

Hypertension in Pregnancy ◽

10.3109/10641950903322923 ◽

2010 ◽

Vol 30 (1) ◽

pp. 45-57 ◽

Cited By ~ 12

Author(s):

Rolando J. J. Ramirez ◽

Julianna Debrah ◽

Jacqueline Novak

Keyword(s):

Perfusion Pressure ◽

Mesenteric Arteries ◽

Pregnant Rats ◽

Myogenic Responses ◽

Uterine Perfusion

Download Full-text

Abstract 293: Endothelial Type B Endothelin Receptor is a Critical Microvascular Target in Placental Ischemia and Tumor Necrosis Factor-Mediated Hypertensive Pregnancy

Hypertension ◽

10.1161/hyp.64.suppl_1.293 ◽

2014 ◽

Vol 64 (suppl_1) ◽

Author(s):

Marc Q Mazzuca ◽

Karina M Mata ◽

Raouf A Khalil

Keyword(s):

Channel Blocker ◽

Hypertensive Disorder ◽

Endothelin Receptor ◽

Type B ◽

Nos Inhibitor ◽

Uterine Perfusion ◽

Mesenteric Microvessels ◽

Placental Ischemia ◽

Necrosis Factor

Preeclampsia is a pregnancy-related hypertensive disorder (HTN-Preg) with unclear mechanism, and a role of cytokines and endothelin-1 (ET-1) has been suggested. We have recently shown downregulation of endothelial type B ET-1 receptor (ET B R) in Preg rats with reduced uterine perfusion pressure (RUPP). To test if cytokines are a possible mechanism linking RUPP to downregulation of ET B R, day 14-Preg rats were either nontreated or infused with TNFα (200 ng/kg/day), and RUPP rats were either nontreated or infused with the TNFα decoy receptor etanercept (0.4 mg/kg/day) for 5 days by osmotic minipump. On day 19, BP was recorded and mesenteric microvessels were isolated for simultaneous measurement of diameter and [Ca 2+ ] i (fura-2 340/380 ratio). BP was in TNFα-Preg (127±8) > Preg (97±5mmHg) and in etanercept-RUPP (113±2) < RUPP (124±3mmHg). ET-1 vasoconstriction was in TNFα-Preg (86.1±4.7) > Preg (58.1±5.2%), and in etanercept-RUPP (65.9±5.0) < RUPP (86.2±3.7%). ET-1 caused parallel increases in microvascular [Ca 2+ ] i that were in TNFα-Preg (0.90±0.01) > Preg (0.86±0.01), and in etanercept-RUPP (0.85±0.01) < RUPP (0.92±0.01). Endothelium removal or microvessel treatment with ET B R antagonist BQ-788 enhanced ET-1 vasoconstriction and [Ca 2+ ] i in Preg and etanercept-RUPP, but not in TNFα-Preg or RUPP. ET B R-mediated relaxation with IRL-1620 was in TNFα-Preg (4.11±6.1) < Preg (28.8±4.2%), and in etanercept-RUPP (20.2±4.6) > RUPP (10.17±2.9%). The NOS inhibitor L-NAME partially reduced ACh-induced and ET B R-mediated relaxation in Preg and etanercept-RUPP, but not TNFα-Preg or RUPP, suggesting decreased NO-dependent and ET B R-mediated vasorelaxation in HTN-Preg. Addition of the K + channel blocker teraethylammonium (non specific), or apamin (SK Ca ) plus TRAM-34 (IK Ca ) abolished the remaining ET B R-mediated relaxation in all groups, suggesting equal role of EDHF. Thus similar to RUPP, increasing TNFα in Preg rats increases ET-1 microvascular constriction and decreases ET B R-mediated NO-dependent vasodilation, and counteracting TNFα reduces BP and ET-1 vasoconstriction, and enhances ET B R-mediated vasodilation in RUPP rats. The results support that endothelial ET B R is a major microvascular target in placental ischemia and TNFα-mediated HTN-Preg.

Download Full-text

Serelaxin improves the pathophysiology of placental ischemia in the reduced uterine perfusion pressure rat model of preeclampsia

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00192.2016 ◽

2016 ◽

Vol 311 (6) ◽

pp. R1158-R1163 ◽

Cited By ~ 19

Author(s):

Jose A. Santiago-Font ◽

Lorena M. Amaral ◽

Jessica Faulkner ◽

Tarek Ibrahim ◽

Venkata Ramana Vaka ◽

...

Keyword(s):

Nitric Oxide ◽

Rat Model ◽

Perfusion Pressure ◽

Resistance Index ◽

Hypertensive Disorder ◽

Pregnant Rats ◽

Tnf Α ◽

Uterine Perfusion ◽

Placental Ischemia ◽

Nitric Oxide Bioavailability

Preeclampsia is a hypertensive disorder of pregnancy that has limited therapeutic options. In healthy pregnancy, relaxin plays an important vasodilatory role to maintain vascular compliance; however, currently, there is no preclinical evidence to support the use of relaxin during preeclampsia. Therefore, the goal of this study was to test the hypothesis that recombinant human relaxin-2 (Serelaxin, Novartis; RLX) could reduce mean arterial pressure (MAP) and improve uterine artery resistance index (UARI) and nitric oxide bioavailability, and/or decrease prepro-endothelin-1 (PPET-1), soluble fms-like tyrosine kinase-1 (sFlt-1), and TNF-α) in the reduced uterine perfusion pressure (RUPP) model of preeclampsia. On day 14 of gestation (GD14), pregnant rats were assigned to normal pregnant (NP), RUPP, RUPP+RLX, or NP+RLX groups. Treated rats received RLX at 0.4 μg/h or RLX2 4 μg/h RLX via minipump implanted on GD14. On GD18, carotid arterial catheters were inserted, and on GD19, MAP and tissues were collected. MAP was increased in RUPP rats compared with NP but was lowered with either dose of RLX. UARI and sFlt-1 were significantly improved in both treated RUPP groups. Total circulating nitrate-nitrite improved and placental PPET-1 and TNF-α were significantly decreased with the higher dose of RLX. Renal cortex PPET-1 was reduced with both doses of RLX. In conclusion, Serelaxin improved blood pressure, sFlt-1, TNF-α, UARI, and nitric oxide bioavailability and PPET-1 in a rat model of preeclampsia, thereby suggesting a potential therapeutic role for RLX in maintaining maternal health and prolonging pregnancy in the face of placental ischemia.

Download Full-text

Increased Myogenic Reactivity of Resistance‐Caliber Mesenteric Arteries from Pregnant Rats with Differential Reductions in Uterine Perfusion Pressure: Impact of Thromboxane

The FASEB Journal ◽

10.1096/fasebj.27.1_supplement.708.11 ◽

2013 ◽

Vol 27 (S1) ◽

Author(s):

John J Reho ◽

Jonathan D Toot ◽

Jennifer Peck ◽

Jacqueline Novak ◽

Rolando J Ramirez

Keyword(s):

Perfusion Pressure ◽

Mesenteric Arteries ◽

Pregnant Rats ◽

Pressure Impact ◽

Uterine Perfusion

Download Full-text

Characterisation of cardiac health in the reduced uterine perfusion pressure model and a 3D cardiac spheroid model, of preeclampsia

Biology of Sex Differences ◽

10.1186/s13293-021-00376-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Claire Richards ◽

Kimberly Sesperez ◽

Michael Chhor ◽

Sahar Ghorbanpour ◽

Claire Rennie ◽

...

Keyword(s):

Perfusion Pressure ◽

Late Onset ◽

Cardiac Fibroblasts ◽

Immunofluorescent Staining ◽

Collagen Deposition ◽

Human Coronary Artery ◽

Pregnant Rats ◽

Cardiac Health ◽

Increased Risk ◽

Uterine Perfusion

Abstract Background Preeclampsia is a dangerous cardiovascular disorder of pregnancy that leads to an increased risk of future cardiovascular and metabolic disorders. Much of the pathogenesis and mechanisms involved in cardiac health in preeclampsia are unknown. A novel anti-angiogenic protein, FKBPL, is emerging as having a potential role in both preeclampsia and cardiovascular disease (CVD). Therefore, in this study we aimed to characterise cardiac health and FKBPL regulation in the rat reduced uterine perfusion pressure (RUPP) and a 3D cardiac spheroid model of preeclampsia. Methods The RUPP model was induced in pregnant rats and histological analysis performed on the heart, kidney, liver and placenta (n ≥ 6). Picrosirius red staining was performed to quantify collagen I and III deposition in rat hearts, placentae and livers as an indicator of fibrosis. RT-qPCR was used to determine changes in Fkbpl, Icam1, Vcam1, Flt1 and Vegfa mRNA in hearts and/or placentae and ELISA to evaluate cardiac brain natriuretic peptide (BNP45) and FKBPL secretion. Immunofluorescent staining was also conducted to analyse the expression of cardiac FKBPL. Cardiac spheroids were generated using human cardiac fibroblasts and human coronary artery endothelial cells and treated with patient plasma from normotensive controls, early-onset preeclampsia (EOPE) and late-onset preeclampsia (LOPE); n = 3. FKBPL and CD31 expression was quantified by immunofluorescent labelling. Results The RUPP procedure induced significant increases in blood pressure (p < 0.001), collagen deposition (p < 0.001) and cardiac BNP45 (p < 0.05). It also induced a significant increase in cardiac FKBPL mRNA (p < 0.05) and protein expression (p < 0.01). RUPP placentae also exhibited increased collagen deposition and decreased Flt1 mRNA expression (p < 0.05). RUPP kidneys revealed an increase in average glomerular size (p < 0.05). Cardiac spheroids showed a significant increase in FKBPL expression when treated with LOPE plasma (p < 0.05) and a trend towards increased FKBPL expression following treatment with EOPE plasma (p = 0.06). Conclusions The rat RUPP model induced cardiac, renal and placental features reflective of preeclampsia. FKBPL was increased in the hearts of RUPP rats and cardiac spheroids treated with plasma from women with preeclampsia, perhaps reflective of restricted angiogenesis and inflammation in this disorder. Elucidation of these novel FKBPL mechanisms in cardiac health in preeclampsia could be key in preventing future CVD.

Download Full-text