title: Hypertension produced by placental ischemia in pregnant rats is associated with increased soluble endoglin expression.
abstract: Recent clinical studies indicate that an excess of angiostatic factors, such as soluble endoglin (sEng), is related to the occurrence of preeclampsia. Although recent clinical studies report that sEng is increased in preeclamptic women, the mechanisms underlying its overexpression remain unclear. Evidence suggests that hypoxia and induction of heme oxygenase-1 have opposing effects on sEng expression, the former stimulatory and the latter inhibitory. Hence, we hypothesized that placental ischemia because of reduced uterine perfusion pressure (RUPP) in the pregnant rat would increase sEng expression and decrease heme oxygenase-1. Mean arterial pressure was obtained via arterial catheter, and serum and placental proteins were measured by Western blot. Mean arterial pressure was increased (132+/-3 mm Hg versus 102+/-2 mm Hg; P<0.001), and fetal (2.35+/-0.05 g versus 1.76+/-0.08 g; P<0.001) and placental weight were decreased (0.47+/-0.04 g versus 0.58+/-0.03 g; P<0.01) in the RUPP compared with normal pregnant controls. Serum sEng (0.10+/-0.02 arbitrary pixel units [apu] versus 0.05+/-0.01 apu; P<0.05) and placental endoglin (4.7+/-2.3 apu versus 1.45+/-0.42 apu; P<0.05) were increased along with placental hypoxia inducible factor-1 alpha (1.42+/-0.25 apu versus 0.68+/-0.09 apu; P<0.05) expression in the RUPP versus the normal pregnant dams. Placental HO-1 (1.4+/-0.3 apu versus 2.5+/-0.1 apu; P<0.05) expression decreased in the RUPP compared with normal pregnant dams. The present findings support our hypothesis that placental ischemia because of RUPP increases the expression of sEng and shifts the balance of angiogenic factors in the maternal circulation toward an angiostatic state. The present study provides further evidence that placental ischemia is a strong in vivo stimulus of angiostatic factors during pregnancy.
authors.affiliation: Department of Physiology, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216-4505, USA.
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Gilbert
authors.forename: Sara A B
authors.initials: SA
authors.lastname: Gilbert
authors.forename: Marietta
authors.initials: M
authors.lastname: Arany
authors.forename: Joey P
authors.initials: JP
authors.lastname: Granger
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004195:Disease Models, Animal; D000071063:Endoglin; D005260:Female; D051547:Heme Oxygenase-1 / Q000378:metabolism; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D007511:Ischemia / Q000378:metabolism*; D010920:Placenta / Q000098:blood supply*; D011225:Pre-Eclampsia / Q000209:etiology / Q000378:metabolism; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000071063:Endoglin; C501740:Eng protein, rat; C497444:Hif1a protein, rat; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D047908:Intracellular Signaling Peptides and Proteins; D051547:Heme Oxygenase-1