Plasma angiotensinogen is associated with higher 24-hour ambulatory blood pressure independently of plasma angiotensin II in obese men

The introduction of liver-targeted antisense oligonucleotides and small interfering ribonucleic acids that inhibit hepatic angiotensinogen synthesis has led to renewed interest in the role of angiotensinogen in hypertension. Therefore, we decided to do further angiotensinogen analyses in a hypertension research program, where we found that obese hypertensive men, given their high salt intake and high 24-hour ambulatory blood pressure (ABP), had higher than expected renin-angiotensin-system (RAS) activity. In a cross-sectional study, we examined 64 newly diagnosed treatment-naïve obese hypertension men (body mass index (BMI) ≥ 30 kg/m2, 24-hour systolic ABP ≥ 130 mm Hg and/or 24-hour diastolic ABP ≥ 80 mm Hg), and 40 obese normotensive men (BMI ≥30 mg/m2, 24-hour systolic ABP <130 and 24-hour diastolic ABP <80 mm Hg). Blood for biochemical evaluation of the RAS was drawn after 60 minutes rest in the supine position. We applied multiple linear regression analysis to explore independent associations. The obese hypertensive men had a higher mean fasting plasma concentration of angiotensinogen than the obese normotensive men (970.4 ± 214.3 nmol/L versus 868.4 ± 173.0 nmol/L, P = 0.013). Adjusted for age and angiotensin II, angiotensinogen was significantly associated with 24-hour systolic ABP (regression coefficient±standard error (mm Hg/100 nmol/L angiotensinogen): 1.8 ± 0.6, P = 0.006), 24-hour diastolic ABP (0.8 ± 0.3, P = 0.021), and 24-hour pulse pressure (1.0 ± 0.4, P = 0.028). Thus, plasma angiotensinogen was associated with higher 24-hour ABPs independently of plasma angiotensin II in obese men. However, further studies are warranted to determine whether angiotensinogen is only a risk marker of high BP or has BP raising effects independent of angiotensin II.