Treatment with nitrate has shown to lower blood pressure in both healthy subjects and hypertensive patients.Beside this nitrate have also shown to decrease arterial stiffness and improve endothelial function.But the effect of nitrate on renal blood flow, kidney function, water and salt balance and vasoactive hormones is still unclear. Therefore, the purpose of this study is to investigate the effect of orally administered nitrate on these parameters. This will be done in a double-blinded, placebo-controlled, crossover study. 20 healthy subjects will be treated, in a randomized order, with both potassium nitrate and placebo separated by at least 4 weeks wash-out.
Inorganic nitrate reduces blood pressure and improves endothelial function in both healthy subjects and hypertensive patients. This effect is thought to be caused through bioconversion to nitric oxide. Thus improving risk factors of cardiovascular decease by increasing vasodilatation, salt regulation and vasoactive hormones.The purpose of this study is to investigate the effect of inorganic nitrate on kidney function, hormones and circulation, which is still unknown. The effect of 4 days treatment with 24 mmol potassium nitrate capsules on heart rate, blood pressure, vasoactive hormones and urinary excretion of sodium and water will be measured in a randomized, placebo controlled, double blinded, crossover study in 20 healthy subjects. Each subject attends 2x2 examination days at least 4 weeks apart. The examination days are divided into 8 clearance periods of 30 min. each. The first 3 are baseline periods and in period 4 1 Liter of saline is administered to detect any difference in renal parameters after NaCl load. If inorganic nitrate supplementation is found to lower blood pressure in addition to favorable renal effects, it could lead to changes in the general treatment of high blood pressure and cardiovascular disease.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
18
1 Liter of Isotonic saline administered I.V.
24 mmol of Potassium nitrate is the active comparator substance, that is ingested every morning for 4 days before and on the examination day.
24 mmol of Potassium nitrate is the placebo substance, that is ingested every morning for 4 days before and on the examination day.
Godstrup Hospital
Herning, Denmark
Glomerular filtration rate (GFR)
mL/minute
Time frame: analysed right after each examination day. (day 1)
Brachial blood pressure (BP)
mmhg
Time frame: analysed right after each examination day. (day 1)
central blood pressure (cSBP)
mmhg
Time frame: analysed right after each examination day. (day 1)
Heart rate
beats pr. min.
Time frame: analysed right after each examination day. (day 1)
Pulse wave velocity (PWV)
measured via Mobilograph
Time frame: analysed right after each examination day. (day 1)
Total vascular resistance (TVR)
measured via Mobilograph
Time frame: analysed right after each examination day. (day 1)
Augmentation index (Aix@75)
measured via Mobilograph
Time frame: analysed right after each examination day. (day 1)
Urinary excretions of aquaporin-2 (u-AQP2)
ng/mmol crea
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
Urinary excretions of epithelial sodium channels (u-ENaCγ)
ng/mmol crea
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
Urinary excretions of Na-Cl cotransporter (u-NCC).
ng/mmol crea
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma concentration of renin (PRC)
pg/mL
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma concentration of angiotensin II (p-AngII)
pg/mL
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma concentration of aldosterone (p-Aldo)
pmol/L
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma concentration of arginine vasopressin (p-AVP)
pg/mL
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma concentration of atrial natriuretic peptide (p-ANP)
pmol/L
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma concentration of brain natriuretic peptide (p-BNP).
pmol/L
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma and urine levels of Nitrate (NO3)
μmol/L
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma and urine levels of nitrite (NO2)
μmol/L
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
plasma and urine levels of cyclic guanosine monophosphate (cGMP).
pmol/mL
Time frame: Centrifuged and hereafter frozen. Analyzed during the following 12 months.
Creatinine clearance (CrCl)
mL/minute
Time frame: analysed right after each examination day. (day 1)
Urinary excretion rate of sodium (U-Na)
mmol/min
Time frame: analysed right after each examination day. (day 1)
Urinary excretion rate of potassium(U-K)
mmol/min
Time frame: analysed right after each examination day. (day 1)
Free water clearance (CH2O)
mL/minute
Time frame: analysed right after each examination day. (day 1)
Fractional excretion of sodium (FENa)
calculated into %
Time frame: analysed right after each examination day. (day 1)
Fractional excretion of potassium (FEK)
calculated into %
Time frame: analysed right after each examination day. (day 1)
Urinary excretion rate of albumin (UAER)
µg/min
Time frame: analysed right after each examination day. (day 1)
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