title: Early gestation dexamethasone programs enhanced postnatal ovine coronary artery vascular reactivity.
abstract: Excessive exposure of the fetus to maternally derived corticosteroids has been linked to the development of adult-onset diseases. To determine if early gestation corticosteroid exposure alters subsequent coronary artery reactivity, we administered dexamethasone (0.28 mg.kg(-1).day(-1)) to pregnant ewes at 27-28 days gestation (term being 145 days). Vascular responsiveness was assessed in endothelium-intact coronary and mesenteric arteries isolated from steroid-exposed and age-matched control fetal sheep at 123-126 days gestation and lambs at 4 mo of age. Lambs exposed to maternal dexamethasone had higher mean arterial blood pressures than the age-matched controls (93 +/- 3 vs. 83 +/- 5 mmHg, P < 0.05). Mesenteric arteries from the steroid-exposed fetuses displayed diminished responses to ANG II, relative to controls. In 4-mo-old lambs, prenatal dexamethasone exposure significantly increased coronary artery vasoconstriction to ANG II, ACh, and U-46619, but not KCl. In contrast, postnatal mesenteric artery reactivity was unaltered by steroid exposure. Compared with fetal mesenteric reactivity, postnatal mesenteric reactivity to ANG II, phenylephrine, and U-46619 was diminished, whereas the response to 120 mmol/l KCl was heightened. Coronary artery ANG II receptor protein expression was not significantly altered by steroid exposure in either age group. These findings demonstrate that early-gestation glucocorticoid exposure programs postnatal elevations in blood pressure and selectively enhances coronary artery responsiveness to second messenger-dependent vasoconstrictors. Glucocorticoid-induced alterations in coronary vascular smooth muscle structure or function may provide a mechanistic link between an adverse intrauterine environment and later cardiovascular disease.
authors.affiliation: Department of Pediatrics, University of Iowa, Iowa City, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Roghair
authors.forename: Fred S
authors.initials: FS
authors.lastname: Lamb
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Miller
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Scholz
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Segar
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002339:Carotid Arteries / Q000187:drug effects / Q000196:embryology / Q000502:physiology; D003331:Coronary Vessels / Q000187:drug effects* / Q000196:embryology / Q000502:physiology; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D005333:Fetus / Q000187:drug effects / Q000502:physiology; D005865:Gestational Age; D005938:Glucocorticoids / Q000494:pharmacology*; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012756:Sheep; D014655:Vascular Resistance / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D005938:Glucocorticoids; D000804:Angiotensin II; D003907:Dexamethasone