Obese persons have low circulating natriuretic peptide concentrations. It has been proposed that this natriuretic handicap could play an important role in the early stage of obesity-related hypertension. The normal physiological response of the natriuretic peptide system to an increase in blood pressure is an increase in natriuretic peptide secretion with concomitant higher circulating natriuretic peptide concentrations. The objective of this study was to investigate whether higher blood pressure would also be related to higher circulating natriuretic peptide concentrations in obese men. To verify that blood pressure had affected the hearts of our study participants, left ventricular mass was estimated.Design and method:
The present study is a cross-sectional study of 103 obese healthy medication-free men. Blood pressure was measured using 24-hour ambulatory blood pressure recordings. Left ventricular mass was calculated using the Cornell voltage-duration product method. Fasting serum concentrations of midregional proatrial natriuretic peptide, a stable serum marker for active atrial natriuretic peptide, were measured. Linear regression analysis was used to calculate age-adjusted standardized regression coefficients (β)Results:
Left ventricular mass and blood pressure increased across systolic ambulatory blood pressure quartiles (mean left ventricular mass ± standard deviation: 1599.1 ± 387.2 mm·ms in the 1st vs. 2188.5 ± 551.3 mm·ms in the 4th quartile, P < 0.001; mean systolic ambulatory blood pressure ± standard deviation: 114.5 ± 4.2 mmHg in the 1st vs. 149.0 ± 7.7 mmHg in the 4th quartile, P < 0.001). Age-adjusted, mean systolic ambulatory blood pressure was robustly associated with left ventricular mass (β=0.48, P < 0.001). Despite evidence of blood pressure-related increases in left ventricular mass, serum midregional proatrial natriuretic peptide concentrations were negatively associated with mean systolic ambulatory blood pressure (β=-0.32, P = 0.004). Serum midregional proatrial natriuretic peptide concentrations were also negatively associated with mean diastolic ambulatory blood pressure (β=-0.45, P < 0.001).Conclusions:
Contrary to known physiological natriuretic peptide responses to increases in blood pressure, serum midregional proatrial natriuretic peptide concentrations were not positively but negatively associated with 24-hour ambulatory blood pressures in our study. Nevertheless, this adds further to the notion that a low amount of circulating natriuretic peptides could play an important role in the early stage of obesity-related hypertension.