Apoptosis and angiotensin II: yet another renal regulatory system?

Apoptosis plays a key role in the regulation of normal renal structure and kidney remodeling in various renal diseases. Angiotensin II plays a prominent role in renal injury through its receptor subtypes, the type 1 (AT1) receptor and the type 2 (AT2) receptor, which involve different molecular mechanisms. In addition to its haemodynamic actions, angiotensin II induces apoptosis. Angiotensin II also increases proliferation in the kidney. A close correlation between renal cell proliferation and apoptosis has been shown in renal diseases as well as in the angiotensin II infusion model. Angiotensin induces upregulation of p53 and other pro-apoptotic proteins. Recent studies suggest that both AT1 and AT2 receptors influence the apoptotic process in the kidney. These apoptotic effects of angiotensin II should be considered as representing another regulatory mechanism that may modulate the balance between cell growth and proliferation within the kidney.