| Angiotensin-(1-7) Deficiency and Baroreflex Impairment Precede the Antenatal Betamethasone Exposure-Induced Elevation in Blood Pressure. | |
| | |
MedLine Citation:
|
PMID: 22215705 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
|
Betamethasone is administered to accelerate lung development and improve survival of premature infants but may be associated with hypertension later in life. In a sheep model of fetal programming resulting from exposure at day 80 of gestation to Betamethasone (Beta-exposed), adult sheep at 6 to 9 months or 1.8 years of age have elevated mean arterial pressure (MAP) and attenuated spontaneous baroreflex sensitivity (sBRS) for control of heart rate compared to age-matched controls associated with imbalances in angiotensin (Ang) II vs Ang-(1-7) tone. At 6 weeks of age, evoked BRS is already low in the Beta-exposed animals. In this study, we assessed the potential contribution of the renin-angiotensin system to the impaired sBRS. Female lambs (6 weeks old) with Beta exposure in utero had similar MAP to control lambs (78±2 vs 77±2 mm Hg, n=4-5 per group), but lower sBRS (8±1 vs 16±3 ms/mm Hg; P<0.05) and impaired heart rate variability. Peripheral AT1 receptor blockade using candesartan lowered MAP in both groups (≈ 10 mm Hg) and improved sBRS and heart rate variability in Beta-exposed lambs to a level similar to control. AT7 receptor blockade by infusion of D-ala Ang-(1-7) (700 ng/kg/min for 45 minutes) reduced sBRS 46%±10% in Beta-exposed vs in control lambs (P<0.15) and increased MAP in both groups (≈ 6±2 mm Hg). Our data reveal that Beta exposure impairs sBRS and heart rate variability at a time point preceding the elevation in MAP via mechanisms involving an imbalance in the Ang II/Ang-(1-7) ratio consistent with a progressive loss in Ang-(1-7) function. |
| | |
Authors:
|
Hossam A Shaltout; James C Rose; Mark C Chappell; Debra I Diz |
Related Documents
:
|
17915295 - Thrombin generation determined by calibrated automated thrombography (cat) in pediatric... 9619385 - Direct measurement of post-prandial portal haemodynamics in cirrhotic patients with a t... 15316215 - Hemodynamic effects of endobronchial application of ornipressin versus terlipressin. 10522045 - Portal hypertension as a complication of chronic pancreatitis. 18326185 - Effect of high hydrostatic pressure processing on freely suspended and bivalve-associat... 17915295 - Thrombin generation determined by calibrated automated thrombography (cat) in pediatric... |
Publication Detail:
|
Type: JOURNAL ARTICLE Date: 2012-1-3 |
Journal Detail:
|
Title: Hypertension Volume: - ISSN: 1524-4563 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
|
Created Date: 2012-1-4 Completed Date: - Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 7906255 Medline TA: Hypertension Country: - |
Other Details:
|
Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
|
Hypertension and Vascular Research Center and Departments of Obstetrics and Gynecology and General Surgery, Wake Forest University School of Medicine, Winston-Salem, NC. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Prognostic Value of the Variability in Home-Measured Blood Pressure and Heart Rate: The Finn-Home St...
Next Document: Transcriptionally Active Syncytial Aggregates in the Maternal Circulation May Contribute to Circulat...