Purpose: To review the evidence that links angiotensin II and endothelin as growth factors and as modifiers of extracellular matrix synthesis in renal cells, with particular reference to the effects of angiotensin converting enzyme (ACE) inhibition in models of renal injury.
In vitro studies: In cultured mesangial cells, both angiotensin II and endothelin promote contraction, proliferation/hypertrophy, signal transduction pathways, the activation of early growth genes, and the generation of inflammatory mediators, cytokines and growth factors. Both hormones have been shown to promote the synthesis of fibronectin and collagen in a dose-dependent manner. ACE inhibition attenuates the effect of endothelin-1, one of three isoforms of endothelin.
Animal studies: In experimental models of renal injury, chiefly in those characterized by increased intraglomerular pressure, ACE inhibition has reduced proteinuria and glomerular and interstitial sclerosis.
Human studies: ACE inhibition has been shown to have major beneficial effects in patients with diabetic nephropathy, even in those with normal blood pressure.
Conclusions: Although the renal-protective effects of ACE inhibitors in experimental and human renal injury may reflect systemic and/or local hemodynamic effects of these drugs, their modulatory actions on extracellular matrix synthesis and proteinuria may contribute to the benefit of ACE-inhibitor therapy.