Angiotensin II type 1 receptor antagonist versus angiotensin I-converting enzyme inhibitor in experimental renal diseases

Angiotensin II has an important role in the structural and functional regul ation of the cardiovascular and renal systems. Blockade of the renin-angiot ensin system can be achieved with angiotensin-converting enzyme (ACE) inhib itors and non-peptidic, orally active, angiotensin II type 1 receptor (AT1) antagonists. However, the question that has yet to be answered is whether ACE inhibitors and ATI receptor antagonists have similar renoprotective eff ects in various experimental diseases. Although many studies have assessed the role of either ACE inhibitors or AT1 receptor antagonists, we have revi ewed the literature comparing both types of blocker in the same experiment. In most models of hypertension or renal failure, both classes of blocker a ppear to have similar antihypertensive and renal profiles. In a few models, the influence of the ACE inhibitor on arterial pressure and/or renal funct ion is more marked than that of the ATI receptor antagonist. Even though th e maximum dose-effect curve for each compound was not often carried out for the systemic haemodynamics and renal alterations, the difference between b oth classes of blocker, when observed, appeared to favour the participation of non-angiotensin II or non-AT1-mediated mechanisms. Among them are the s timulation of prostaglandin production, kinin accumulation, nitric oxide ge neration and modulation of endothelin or TGF beta1 expression via direct or indirect pathways. Future experimental and probably human studies aimed at comparing angiotensin II receptor antagonists and ACE inhibitors, with res pect to blood pressure and renal damage, should be designed with all these concerns in mind. (C) 2000 Editions scientifiques et medicales Elsevier SAS .