Objectives: The local renin-angiotensin system is important in cardiovascular diseases. The present study examined the association between angiotensin (Ang) II-forming activity in fractionated peripheral leukocytes and atherosclerotic risks such as blood pressure, smoking, age and serum cholesterol level, and used a new analytical approach for the measurement of chymase-like activity in peripheral blood to assess the relationship between the chymase-like activities in leukocytes and atherosclerotic risks.
Methods: Peripheral blood samples were obtained from normal and high blood pressure patients in the presence or absence of ischemic heart disease. Mononuclear cell or polymorphonuclear cell fraction of leukocyte was isolated by centrifugation with either Lymphoprep or Polymorphprep, respectively. Chymase-like, angiotensin converting enzyme, and cathepsin G-dependent Ang II-forming activities in the homogenates of mononuclear cell or polymorphonuclear cell fraction were measured using Ang I as a substrate.
Results: The chymase-like Ang II-forming activity in the mononuclear cell fraction slightly or significantly increased in non-smoker patients with high blood pressure (systolic and diastolic blood pressure, p = 0.11; mean blood pressure, p < 0.05). Chymase-like Ang II-forming activity in the mononuclear cell fraction positively correlated with serum total cholesterol (p < 0.05) level.
Conclusions: Our data indicates that chymase in mononuclear cells from peripheral blood is activated by high blood pressure or hypercholesterolemia.