Contribution of circulating renin to local synthesis of angiotensin peptides in the heart

The activity of a local cardiac renin-angiotensin system (RAS) has long bee n suspected in the promotion of cardiac pathologies including hypertrophy, ischemia, and infarction. All of the components of the RAS cascade have bee n demonstrated to be synthesized within the heart with the possible excepti on of the first enzyme in the cascade, renin. In the current study, we prov ide direct evidence that circulating renin can contribute to cardiac-specif ic synthesis of angiotensin peptides. Furthermore, we demonstrate this effe ct is independent of blood pressure and that in animals of comparable blood pressure, elevated circulating renin significantly enhances cardiac fibros is. These results may serve to explain some of the cardiac pathologies asso ciated with the RAS.