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Angiotensin receptor antagonists in experimental models of chronic renal failure
1Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
Abstract:
The efficacy of angiotensin converting enzyme inhibitors (ACEI) in slowing the advancement of chronic renal disease attests to the importance of angiotensin II (Ang II) in the pathophysiological mechanisms underlying disease progression. It is apparent from studies of the effects of orally-active AT1 receptor antagonists (AT1RA) in experimental models of chronic progressive renal disease, that AT1RA have broadly similar effects to those of ACEI, implying that the favorable effects of ACEI on systemic and renal hemodynamics and indices of glomerular injury are mediated, in large part, by reducing the action of Ang II at AT1 receptors. The possibility remains, however, that differences in the modes of action of ACEI and AT1RA are significant in terms of renal protection and that the two classes of drugs are not therapeutically equivalent. Thus far, however, virtually all experimental studies comparing the renal protective effects of ACEI versus AT1RA have failed to show any convincing differences between the two classes of drug that cannot be attributed to discrepancies in the levels of blood pressure control achieved. As many rodent studies have adopted protocols originally designed to distinguish between the effects of treatment versus no treatment, however, it may be premature to conclude that ACEI and AT1RA are, essentially, therapeutically equivalent. Since both classes of drug have such potent renoprotective effects, the extent of injury that develops in treated rats may be so slight as to compromise the sensitivity of the experimental comparison. Fresh experimental approaches may be required to overcome this issue and resolve any outstanding questions concerning the therapeutic equivalence of AT1RA and ACEI in slowing the progression of renal disease.
Insights
Angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor antagonists (AT1RA) both protect kidneys by targeting angiotensin II. However, definitive therapeutic equivalence in slowing chronic kidney disease progression remains unproven.
Area of Science:
- Nephrology
- Pharmacology
- Cardiovascular Research
Background:
- Angiotensin II (Ang II) plays a key role in chronic kidney disease (CKD) progression.
- Angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor antagonists (AT1RA) are known to slow CKD.
- Both drug classes likely exert renoprotective effects by inhibiting Ang II actions at AT1 receptors.
Purpose of the Study:
- To investigate the therapeutic equivalence of ACEI and AT1RA in slowing the progression of chronic renal disease.
- To determine if differences in the mechanisms of action between ACEI and AT1RA have significant implications for renal protection.
- To assess whether current experimental models are sufficiently sensitive to detect potential therapeutic differences.
Main Methods:
- Review of experimental studies comparing the renal protective effects of ACEI and AT1RA in models of progressive renal disease.
- Analysis of findings in relation to blood pressure control achieved with each drug class.
- Consideration of limitations in existing study protocols, particularly those designed for treatment versus no-treatment comparisons.
Main Results:
- Most comparative studies show similar renoprotective effects between ACEI and AT1RA, often attributable to comparable blood pressure reduction.
- Existing studies may lack the sensitivity to detect subtle differences due to potent renoprotective effects limiting observable injury.
- Previous research has not conclusively demonstrated therapeutic superiority of one class over the other.
Conclusions:
- While both ACEI and AT1RA demonstrate significant renoprotection, their therapeutic equivalence in slowing CKD progression requires further investigation.
- Current evidence suggests similar efficacy, but potential differences in mechanism may be masked by effective blood pressure control and study design limitations.
- Novel experimental approaches may be necessary to definitively resolve questions regarding the comparative efficacy of ACEI and AT1RA in renal protection.