Abstract 30: Urinary Exosome miRNome Analysis and its Application to Salt-Sensitivity of Blood Pressure
Definitive biomarkers are needed in order to improve diagnostics for salt-sensitivity of blood pressure and hypertension. Exosomes are small vesicles, 50-90 nm in diameter, released from renal tubular epithelial cells into urine, which may contain sub-cellular components that could serve as diagnostic biomarkers. Total miRNA (miRNome) in urinary exosomes has not been previously examined for disease biomarkers, particularly for hypertension and/or salt sensitivity. Following ultracentrifugation of urine, total RNA was collected from urinary exosomes and analyzed by array analysis by LC Sciences (miRBase Human version 18). Three samples per individual of urinary exosomes were isolated and pooled from five human subjects previously typed for salt-sensitivity index from a prior clinical study using a two week controlled sodium diet. Patients were stratified according to salt sensitivity status: High salt-sensitive (HSS) patients’ mean arterial blood pressure (MAP) increased on high salt diet by >7mmHg, low salt-sensitive (LSS) patients MAP increased on low salt diet by >7mmHg, and salt-resistant (SR) patients MAP changed <7mmHg between the high and low salt diet. 306 miRNA targets out of 1898 probes were above background providing the first data for urinary exosome miRNome in humans (n=5). Bioinformatic analysis determined 20 significant differences in miRNome patterns between the HSS, SR, and LSS individuals (n=4, P<0.01). These data demonstrate the first examination of the urinary exosomal miRNome as it relates to sodium-induced blood pressure changes and suggest that it may constitute a convenient diagnostic test for salt-sensitivity of blood pressure.
- © 2012 by American Heart Association, Inc.