Neutrophil Depletion Attenuates Placental Ischemia-Induced Hypertension in the Rat

Regal, Jean F.; Lillegard, Kathryn E; Bauer, Ashley J.; Elmquist, Barbara J.; Loeks-Johnson, Alex C.; Gilbert, Jeffrey S.

doi:10.1371/journal.pone.0132063

Cited by 40 publications

(28 citation statements)

References 72 publications

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“…In RUPP rats, inhibition of complement activation causes a decrease in BP independent of alterations in pro-angiogenic levels, suggesting complement activation in HTN-Preg (Lillegard et al, 2013). Also, depletion of neutrophils causes a decrease in BP in RUPP rats, supporting a role for innate immune response in HTN-Preg (Regal et al, 2015). …”

Section: Placental Ischemia As An Initiating Event In Preeclampsiamentioning

confidence: 76%

Mechanisms of Endothelial Dysfunction in Hypertensive Pregnancy and Preeclampsia

Possomato-Vieira

Khalil

2016

Advances in Pharmacology

181

117

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Preeclampsia is a pregnancy-related disorder characterized by hypertension, and could lead to maternal and fetal morbidity and mortality. Although the causative factors and pathophysiological mechanisms are unclear, endothelial dysfunction is a major hallmark of preeclampsia. Clinical tests and experimental research have suggested that generalized endotheliosis in the systemic, renal, cerebral and hepatic circulation could decrease endothelium-derived vasodilators such as nitric oxide, prostacyclin and hyperpolarization factor and increase vasoconstrictors such as endothelin-1 and thromboxane A2, leading to increased vasoconstriction, hypertension and other manifestation of preeclampsia. In search for the upstream mechanisms that could cause endothelial dysfunction, certain genetic, demographic and environmental risk factors have been suggested to cause abnormal expression of uteroplacental integrins, cytokines and matrix metalloproteinases, leading to decreased maternal tolerance, apoptosis of invasive trophoblast cells, inadequate spiral arteries remodeling, reduced uterine perfusion pressure (RUPP), and placental ischemia/hypoxia. RUPP may cause imbalance between the anti-angiogenic factors soluble fms-like tyrosine kinase-1 and soluble endoglin and the pro-angiogenic factors vascular endothelial growth factor and placental growth factor, or stimulate the release of other circulating bioactive factors such as inflammatory cytokines, hypoxia-inducible factor-1, reactive oxygen species, and angiotensin AT1 receptor agonistic autoantibodies. These circulating factors could then target endothelial cells and cause generalized endothelial dysfunction. Therapeutic options are currently limited, but understanding the factors involved in endothelial dysfunction could help design new approaches for prediction and management of preeclampsia.

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Section: Placental Ischemia As An Initiating Event In Preeclampsiamentioning

confidence: 76%

Mechanisms of Endothelial Dysfunction in Hypertensive Pregnancy and Preeclampsia

Possomato-Vieira

Khalil

2016

Advances in Pharmacology

181

117

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“…The reduced utero-placental perfusion pressure (RUPP) procedure was used to model placental ischemia induced hypertension in third trimester pregnant rat as previously described (Lillegard et al, 2013; Lillegard et al, 2014; Regal et al, 2015b). Timed pregnant Sprague Dawley dams (Crl:CD IGS, Charles River Laboratories, Portage, MI) were anesthetized with isoflurane on gestation day (GD)14.5 with the date of vaginal plug designated as GD0.5.…”

Section: Methodsmentioning

confidence: 99%

Role of IgM and angiotensin II Type I receptor autoantibodies in local complement activation in placental ischemia-induced hypertension in the rat

Regal

Strehlke

Peterson

et al. 2016

Molecular Immunology

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Preeclampsia is characterized by development of hypertension during pregnancy and reduced placental perfusion. Previous studies in a rat model of placental ischemia-induced hypertension demonstrated that inhibiting complement activation attenuated increased maternal blood pressure with C3a and C5a identified as the important products of complement activation. Given that in other forms of ischemia both natural IgM and antigen antibody complexes initiate complement activation, we hypothesized that placental ischemia exposes neoepitopes recognized by IgM to cause local complement activation and hypertension. Alternatively, we postulated that autoantibody to angiotensin II Type 1 receptor (AT1-AA) interacts with AT1 receptors to cause complement activation. Since complement activation occurs in kidney and placenta in preeclampsia, we used immunohistochemistry to determine IgM deposition and local complement activation in each organ (C3 deposition), and quantitative real-time polymerase chain reaction (qRT-PCR) to quantitate mRNA for endogenous regulators of complement activation CD55, CD59 and Complement receptor 1-related gene/protein y (Crry). On gestation day (GD)14.5, timed pregnant Sprague Dawley rats underwent Sham surgery or placement of clips on inferior abdominal aorta and ovarian arteries to create placental ischemia using the reduced utero-placental perfusion pressure (RUPP) model. As previously reported, RUPP surgery increased mean arterial pressure and circulating C3a on GD19.5. In placenta, IgM and C3 deposition increased, whereas mRNA for complement regulators Crry and CD59 decreased along with Crry protein in RUPP compared to Sham treated animals. In kidney, IgM deposition increased in animals subjected to RUPP vs Sham surgery without a significant change in C3 deposition and coincident with an increase in mRNA for CD55 and CD59. The AT1 receptor antagonist losartan prevents placental ischemia-induced hypertension as well as AT1-AA interaction with AT1 receptors. However, losartan did not attenuate complement activation as measured by circulating C3a or placental C3 deposition. Importantly, our studies indicate that following placental ischemia, complement activation is not due to AT1-AA but is associated with IgM deposition. These studies suggest a role for natural antibodies interacting with placental ischemia-induced neoepitopes to activate complement and contribute to hypertension.

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“…82 Interestingly, inhibition of complement activation or depletion of neutrophils decreases blood pressure in the RUPP rat model of placental ischemia, supporting a role of complement activation and innate immune response in hypertension in pregnancy. 81,83 …”

Section: Abnormal Placentation and Placental Ischemia In Preeclampsiamentioning

confidence: 99%

Matrix Metalloproteinases in Normal Pregnancy and Preeclampsia

Chen

Khalil

2017

Progress in Molecular Biology and Translational Science

228

168

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Normal pregnancy is associated with marked hemodynamic and uterine changes that allow adequate uteroplacental blood flow and uterine expansion for the growing fetus. These pregnancy-associated changes involve significant uteroplacental and vascular remodeling. Matrix metalloproteinases (MMPs) are important regulators of vascular and uterine remodeling. Increases in MMP-2 and MMP-9 have been implicated in vasodilation, placentation and uterine expansion during normal pregnancy. The increases in MMPs could be induced by the increased production of estrogen and progesterone during pregnancy. MMP expression/activity may be altered during complications of pregnancy. Decreased vascular MMP-2 and MMP-9 may lead to decreased vasodilation, increased vasoconstriction, hypertensive pregnancy and preeclampsia. Abnormal expression of uteroplacental integrins, cytokines and MMPs may lead to decreased maternal tolerance, apoptosis of invasive trophoblast cells, inadequate remodeling of spiral arteries, and reduced uterine perfusion pressure (RUPP). RUPP may cause imbalance between the anti-angiogenic factors soluble fms-like tyrosine kinase-1 and soluble endoglin and the pro-angiogenic vascular endothelial growth factor and placental growth factor, or stimulate the release of inflammatory cytokines, hypoxia-inducible factor, reactive oxygen species, and angiotensin AT1 receptor agonistic autoantibodies. These circulating factors could target MMPs in the extracellular matrix as well as endothelial and vascular smooth muscle cells, causing generalized vascular dysfunction, increased vasoconstriction and hypertension in pregnancy. MMP activity can also be altered by endogenous tissue inhibitors of metalloproteinases (TIMPs) and changes in the MMP/TIMP ratio. In addition to their vascular effects, decreases in expression/activity of MMP-2 and MMP-9 in the uterus could impede uterine growth and expansion and lead to premature labor. Understanding the role of MMPs in uteroplacental and vascular remodeling and function could help design new approaches for prediction and management of preeclampsia and premature labor.

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Neutrophil Depletion Attenuates Placental Ischemia-Induced Hypertension in the Rat

Cited by 40 publications

References 72 publications

Mechanisms of Endothelial Dysfunction in Hypertensive Pregnancy and Preeclampsia

Mechanisms of Endothelial Dysfunction in Hypertensive Pregnancy and Preeclampsia

Role of IgM and angiotensin II Type I receptor autoantibodies in local complement activation in placental ischemia-induced hypertension in the rat

Matrix Metalloproteinases in Normal Pregnancy and Preeclampsia

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