Interactions of angiotensin-converting enzyme, kinins and nitric oxide in circulation and the beneficial effects of ACE inhibitors in cardiovascular diseases

Renin-angiotensin-aldosterone systems play a critical role in the developme nt and progression of cardiovascular diseases, and inhibitors of angiotensi n-converting enzyme have proven effective for the treatment of these diseas es. Since angiotensin II receptor antagonists can inhibit the effects of an giotensin II via ACE-independent pathways, e.g., chymase, they were conside red to be more effective than ACEIs. On the other hand, ACE inhibitors can increase bradykinin, and thus, nitric oxide, which may cause potent cardiop rotection, inhibition of smooth muscle proliferation and attenuation of inf lammation mechanisms. It appears that angiotensin II receptor antagonists a nd ACEIs may mediate cardioprotection in different ways. This is the ration ale to explore the possibility of a combined administration of both drugs f or the treatment of chronic heart failure and other cardiovascular patholog y. In this review we try to analyze the role of ACE, kinins and chymase inh ibition in the pathophysiology and treatment of cardiovascular diseases.