Higher angiotensinogen levels tied to higher blood pressure

Despite lower levels on average in males compared to females, the researchers suggest "the association between angiotensinogen and blood pressure was more positive in males, which may be attributed to sex differences in angiotensinogen metabolism and the expression of receptors for Ang peptides."

Angiotensinogen is the precursor of the angiotensin peptide hormones of the RAAS (renin-angiotensin-aldosterone system); clinical trials are ongoing targeting angiotensinogen for treating hypertension and heart failure. There is no clear definition of the epidemiology of angiotensinogen, particularly its relationship to sex, ethnicity and BP/hypertension.

Against the above background, Patrick J. Trainor from New Mexico State University in Las Cruces, New Mexico, USA, and colleagues aimed to determine the relationship of circulating angiotensinogen levels to sex, ethnicity, BP, prevalent hypertension, and incident hypertension in a modern sex-balanced ethnically diverse cohort.

For this purpose, the researchers measured plasma angiotensinogen levels in 5,786 participants from the MESA (Multi-Ethnic Study of Atherosclerosis). The association of angiotensinogen were examined with BP, incident hypertension, and prevalent hypertension.

The study led to the following findings:

• Angiotensinogen levels were remarkably higher in females than males and variated across self-reported ethnicities with the ordering (from lowest to highest): Chinese, Hispanic, Black, and White adults.
• Higher levels were associated with higher BP and odds of prevalent hypertension after adjusting for other risk factors.
• Equivalent relative differences in angiotensinogen were associated with more significant differences in BP in males vs females.
• A standard deviation increment in log-angiotensinogen was associated with 2.61 mm Hg higher systolic BP in males not taking RAAS-blocking medications. The same increment in angiotensinogen was associated with 0.97 mm Hg more elevated systolic BP in females.

"Our findings revealed that females had higher median levels of angiotensinogen than males and that higher levels were linked with higher blood pressure and higher odds of hypertension," the authors wrote. "Despite males having lower levels on average than females, angiotensinogen and BP association were more positive in males, which may be due to sex differences in the angiotensinogen and expression of receptors for Ang peptides," they explained.

They also showed ethnicity-associated variation in angiotensinogen levels, with White participants having the highest levels than Hispanic, Black, and Chinese participants.

"Additional studies are indicated to evaluate the genetic determinants of angiotensinogen concentration and the sex hormones' effect on the relationship of angiotensin to BP," they concluded.

Reference:

The study titled "Blood Levels of Angiotensinogen and Hypertension in the Multi-Ethnic Study of Atherosclerosis (MESA)," was published in the Journal of the American College of Cardiology (JACC). DOI: https://www.jacc.org/doi/10.1016/j.jacc.2023.01.033