UROMODULIN - A LINK BETWEEN SODIUM EXCRETION AND ALTERATION IN CIRCADIAN BLOOD PRESSURE PATTERN IN PREHYPERTENSIVES.

ABSTRACT

Although changes in dietary sodium intake alter blood pressure (BP) in salt-sensitive individuals, pathophysiological mechanisms are still unknown. It has been reported that uromodulin is involved in sodium tubular transport, and genome-wide association studies pointed to UMOD gene as one of the most important gene candidates for arterial hypertension. Our aim was to analyze urinary uromodulin, salt intake and BP in 326 young middle-aged subjects (mean age 36±8 years, 49.4% male). In a subgroup of 175 individuals, ambulatory blood pressure monitoring and echocardiogram were performed. Uromodulin was determined by ELISA. According to the JNC-7 criteria, subjects were classified as optimal BP (n=103, men 72%), prehypertension (PHT) (n=143, men 43%) and hypertension (HT) (n= 80, men 38%). There were no differences in age, salt intake, estimated glomerular filtration rate, sodium excretion and uromodulin among BP groups. However, in PHT subjects, uromodulin was positively associated with fractional sodium excretion and negatively with 24-h sodium excretion and diastolic BP dip. These findings point to the effect of uromodulin on sodium reabsorption along the nephron and consequently circadian BP alteration in prehypertensives.