Polycystic kidney disease (ADPKD) is a common genetic disorder, characterized by the formation of cysts in the kidneys, causing gradual renal function-loss. Previous studies have shown that, reduced glomerular filtration rate (GFR) and renal plasma flow (RPF) play a role in the progression of renal disease in ADPKD. Tolvaptan is a vasopressin 2 antagonist, which seems to reduce the growth of total kidney volume (TKV) and the decline in e-GFR in ADPKD. The mechanism is not fully understood and could, at least partly, be caused by stimulation of the renal blood flow. The purpose of this trial is to investigate if tolvaptan´s improve renal blood flow and glomerular filtration in ADPKD, in a randomized, cross-over, double-blind, placebo-controlled study.
The aim is to measure the acute effects of tolvaptan on: 1. Renal hemodynamics (RPF, GFR, filtration fraction ((FF)) and renovascular resistance ((RVR)) 2. Blood pressure (central blood pressure ((cBP)) and brachial blood pressure bBP) 3. Several vasoactive hormones (plasma renin ((PRC)), plasma angiotensin II ((p-Ang-II)), plasma aldosterone ((p-Aldo)), plasma vasopressin ((p-AVP)) in patients with ADPKD.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
20
Departments of medical research and medicine
Holstebro, Denmark
Renal plasma flow (RPF)
Estimated by posterior Technetium-99m diethylenetriamine penta-acetic acid (99-mTc-DTPA) renography 2 hours after trial medicine intake. (unit of measurement= ml/min)
Time frame: Two hours after trial medicine intake
Central and brachial blood pressures (BP)
Measured using Mobil-O-Graph® PWA (unit of measurement= mmHg)
Time frame: Measured every 15 minutes during the examination day
Glomerular filtration rate (GFR)
Estimated by posterior Technetium-99m diethylenetriamine penta-acetic acid (99-mTc-DTPA) renography 2 hours after trial medicine intake. (unit of measurement= ml/min)
Time frame: Two hours after trial medicine intake
Filtration fraction (FF)
Estimated by posterior Technetium-99m diethylenetriamine penta-acetic acid (99-mTc-DTPA) renography 2 hours after trial medicine intake. (unit of measurement= %)
Time frame: Two hours after trial medicine intake
Plasma concentration of vasopressin (p-AVP)
Blood samples (unit of measurement= pg/ml)
Time frame: Measured before and 3 hours after trial medicine intake
Plasma concentration of aldosterone (p-Aldo)
Blood samples (unit of measurement= pmol/ml)
Time frame: Measured before and 3 hours after trial medicine intake
Plasma concentration of angiotensin II (p-AngII)
Blood samples (unit of measurement= pg/ml)
Time frame: Measured before and 3 hours after trial medicine intake
Plasma concentration of renin (PRC)
Blood samples (unit of measurement= pg/ml)
Time frame: Measured before and 3 hours after trial medicine intake
Urine excretion of aquaporin 2 (u-AQP2)
Urine sample (unit of measurement= ng/ml)
Time frame: Measured before and 3 hours after trial medicine intake
Urine output (OU)
Urine sample (unit of measurement= ml/min)
Time frame: Measured before and 3 hours after trial medicine intake
Urine osmolality (U-osm)
Urine sample (unit of measurement= mosmol/kg)
Time frame: measured before and 3 hours after trial medicine intake
Fractional excretion of sodium (FENa)
Blood and urine sample (unit of measurement= %)
Time frame: Measured before and 3 hours after trial medicine intake
Albumin excretion rate
Blood and urine sample (unit of measurement= mg/min)
Time frame: Measured before and 3 hours after trial medicine intake
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