Effects of Vitamin D on Renin Expression in Hypertensive Patients
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ClinicalTrials.gov Identifier: NCT00585442
(Lack of quality data)
The cardiovascular effects of vitamin D therapy (in humans) have been documented only in patients with known vitamin D deficiency or hyperparathyroidism (a surrogate marker of inadequate vitamin D activity). It is unknown whether the cardiovascular benefits of vitamin D therapy extend beyond these patients to the general hypertensive population. We propose to directly measure the effect of vitamin D therapy on plasma renin activity (PRA), plasma renin concentration (PRC), renin transcription (in mononuclear leukocytes), and blood pressure in hypertensive (but otherwise healthy) patients in a randomized, controlled, experimental trial. This will be the first study to assess vitamin D receptor (VDR) biological (PRA, PRC, renin mRNA, and polymorphisms) and hypertensive activity in patients without vitamin D deficiency. We hypothesize that vitamin D inhibition of renin transcription will produce significant reductions in PRA, PRC, renin transcription, inflammatory cytokines, SBP, and DBP, with potential variation by VDR genotype. Such a result may prove to be significant in the treatment of hypertension, as even modest blood pressure reductions (5 mmHg) are associated with a 14% reduction in mortality due to stroke, a 9% reduction in mortality due to CHD, and a 7% overall reduction in all-cause mortality.
Compare plasma renin activity (PRA) and plasma renin concentration (PRC) in hypertensive patients (JNC VII stage I) following 14 days treatment with calcitriol (1α, 25-[OH]2 vitamin D3) or matched placebo. [ Time Frame: 13 MONTHS (MAY 2007-JUNE 2008) ]
Secondary Outcome Measures
Compare mononuclear leukocyte renin transcription (mRNA) between calcitriol and matched placebo. [ Time Frame: 13 MONTHS (MAY 2007-JUNE 2008) ]
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Ages Eligible for Study:
55 Years and older (Adult, Senior)
Sexes Eligible for Study:
Accepts Healthy Volunteers:
Male or female patients age > 55 years.
Female patients must be postmenopausal, as determined by surgical hysterectomy or 12 month history since last active menstruation
Stage I hypertension (JNC VII Criteria): mean systolic blood pressure (mSBP) 140-159 mmHg and mean diastolic blood pressure 90 - 99 mmHg (mDBP)2
Provide informed consent
Serum vitamin D <55 pmol/L
Serum calcium >10.5 mg/dL
Serum phosphate (inorganic) >5.5 mg/dL
Serum parathyroid hormone (PTH) >1.3 pmol/L
Vitamin D supplements, calcium supplements, estrogen replacement therapy, corticosteroids (inhaled/oral), or hydroxymethyl glutarate CoA reductase inhibitors (statins) within 30 days prior to randomization
Stage II hypertension (JNC VII criteria): mSSBP >160 mmHg or mSDBP >100 mmHg
Use of alpha2-agonists, beta-blockers, or more than 2 anti-hypertensive medications at screening
Estimated creatinine clearance <30 mL/min by Crockroft-Gault Formula
History of heart failure (HF), acute myocardial infarction (AMI), acute coronary syndrome (ACS), transient ischemic attack (TIA), cerebrovascular accident (CVA), peripheral vascular disease (PVD), or known clotting disorder
Insulin dependent diabetes mellitus (patients stabilized on oral regimens may be enrolled)
History of hypersensitivity reaction to 1α, 25-(OH)2 vitamin D3 (calcitriol)
Vitamin D Deficiency
Physiological Effects of Drugs
Bone Density Conservation Agents
Calcium Channel Agonists
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action