Hypertensive and Normal Pregnancy--Calcium Metabolism and Renin-Angiotensin - SCOR in Hypertension
Primary Purpose
Cardiovascular Diseases, Heart Diseases, Hypertension
Status
Completed
Phase
Locations
Study Type
Observational
Intervention
Sponsored by
About this trial
This is an observational trial for Cardiovascular Diseases
Eligibility Criteria
No eligibility criteria
Sites / Locations
Outcomes
Primary Outcome Measures
Secondary Outcome Measures
Full Information
NCT ID
NCT00005456
First Posted
May 25, 2000
Last Updated
May 12, 2016
Sponsor
National Heart, Lung, and Blood Institute (NHLBI)
1. Study Identification
Unique Protocol Identification Number
NCT00005456
Brief Title
Hypertensive and Normal Pregnancy--Calcium Metabolism and Renin-Angiotensin - SCOR in Hypertension
Study Type
Observational
2. Study Status
Record Verification Date
March 2005
Overall Recruitment Status
Completed
Study Start Date
December 1990 (undefined)
Primary Completion Date
undefined (undefined)
Study Completion Date
November 1995 (Actual)
3. Sponsor/Collaborators
Name of the Sponsor
National Heart, Lung, and Blood Institute (NHLBI)
4. Oversight
5. Study Description
Brief Summary
To study calcium metabolism and the renin-angiotensin system in hypertensive and normal pregnancy.
Detailed Description
BACKGROUND:
Beginning in Fiscal Year 1975, the multidisciplinary SCOR examined causes, consequences, and treatments of human hypertension. A central theme was the renal basis for human hypertension. The subproject on calcium metabolism and the renin-angiotensin system in hypertensive and normal pregnancy began in December, 1990.
DESIGN NARRATIVE:
A longitudinal study was performed on normal pregnant women and women with chronic hypertension who had a high incidence of superimposed preeclampsia. In a previous study, the investigators had demonstrated that preeclampsia was associated with reduced urinary excretion of calcium and with lower plasma renin activity (PRA) compared with normal pregnancy. The goal of the investigators was to identify the metabolic and cellular basis for these alterations in calcium homeostasis and in the renin angiotensin system. They tested two hypotheses. The first hypothesis was that diminished placental and/or renal production of 1,25-dihydroxyvitamin D, leading to lower serum calcium, higher parathyroid hormone, and increased renal tubular reabsorption of calcium, was the metabolic basis for hypocalciuria in preeclampsia. The second hypothesis was that lower PRA in preeclampsia was due to systemic and renal vasoconstriction with hypertension and diminished natriuresis.
Serial measurements of 1,25-dihydroxyvitamin D, parathyroid hormone, serum ionized calcium, PRA, estradiol and progesterone, and urinary calcium and electrolytes were obtained, particularly at the onset of preeclampsia. Acute renal hemodynamic studies were also performed in women with preeclampsia and in gestational age matched normals. The studies investigated the relationships among glomerular filtration rate, renal blood flow, parathyroid hormone, vitamin D, atrial natriuretic factor, renin, estradiol and progesterone, and sodium and calcium excretion during infusion of inulin and PAH with either saline or calcium chloride.
Intracellular free calcium concentration in platelets and lymphocytes of pregnant women participating in longitudinal and acute renal hemodynamic studies were also measured. Basal and stimulated (with angiotensin II, ionomycin and thrombin), intracellular free calcium concentrations were compared in normal and hypertensive pregnant women and correlated with calcium regulatory hormones, plasma renin activity and hypertension.
The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.
6. Conditions and Keywords
Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Cardiovascular Diseases, Heart Diseases, Hypertension, Eclampsia, Pre-Eclampsia
7. Study Design
10. Eligibility
Sex
Male
Maximum Age & Unit of Time
100 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
No eligibility criteria
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Phyllis August
Organizational Affiliation
Weill Medical College of Cornell University
12. IPD Sharing Statement
Citations:
PubMed Identifier
8039849
Citation
Blank SG, Helseth G, Pickering TG, West JE, August P. How should diastolic blood pressure be defined during pregnancy? Hypertension. 1994 Aug;24(2):234-40. doi: 10.1161/01.hyp.24.2.234.
Results Reference
background
PubMed Identifier
8027239
Citation
Sealey JE, Itskovitz-Eldor J, Rubattu S, James GD, August P, Thaler I, Levron J, Laragh JH. Estradiol- and progesterone-related increases in the renin-aldosterone system: studies during ovarian stimulation and early pregnancy. J Clin Endocrinol Metab. 1994 Jul;79(1):258-64. doi: 10.1210/jcem.79.1.8027239.
Results Reference
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PubMed Identifier
9541274
Citation
Baylis C, Beinder E, Suto T, August P. Recent insights into the roles of nitric oxide and renin-angiotensin in the pathophysiology of preeclamptic pregnancy. Semin Nephrol. 1998 Mar;18(2):208-30.
Results Reference
background
PubMed Identifier
8588110
Citation
Hojo M, August P. Calcium metabolism in normal and hypertensive pregnancy. Semin Nephrol. 1995 Nov;15(6):504-11.
Results Reference
background
PubMed Identifier
7707813
Citation
August P, Mueller FB, Sealey JE, Edersheim TG. Role of renin-angiotensin system in blood pressure regulation in pregnancy. Lancet. 1995 Apr 8;345(8954):896-7. doi: 10.1016/s0140-6736(95)90012-8.
Results Reference
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Hypertensive and Normal Pregnancy--Calcium Metabolism and Renin-Angiotensin - SCOR in Hypertension
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