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Free radical production and angiotensin
1University of Hamburg, University Hospital Eppendorf, Department of Medicine, Division of Nephrology and Osteology, Pavilion 61, Martinistrasse 52, D-20246 Hamburg, Germany. WOLF@UKE.uni-hamburg.de
Current Hypertension Reports
|September 12, 2000
Summary
Angiotensin II (ANG II) stimulates reactive oxygen species (ROS) production in cardiovascular and renal cells, contributing to diseases like hypertension. While some drugs targeting ANG II may offer antioxidant benefits, clinical evidence is limited to specific patient groups.
Area of Science:
- Cardiovascular Biology
- Renal Physiology
- Oxidative Stress
Background:
- Angiotensin II (ANG II) exerts significant effects on cardiovascular and renal cells, including vasoconstriction, cell growth, and inflammation.
- Emerging evidence indicates ANG II stimulates intracellular reactive oxygen species (ROS) formation, particularly superoxide anion (O2-), via NAD(P)H-oxidases.
- This ANG II-mediated ROS production, though distinct from phagocytic respiratory bursts, is linked to AT1-receptor activation and upregulation of enzyme subunits.
Purpose of the Study:
- To explore the role of ANG II-induced ROS in cardiovascular and renal pathophysiology.
- To investigate the potential of ANG II-targeting drugs as antioxidants in vascular and renal diseases.
- To clarify the clinical utility of ACE inhibitors and AT1-receptor antagonists in managing ANG II-related conditions.
Main Methods:
- Review of current literature on ANG II signaling and ROS generation.
- Analysis of studies investigating the involvement of ROS in cellular pathways (e.g., AP-1, NF-kappaB).
- Evaluation of clinical trial data for ACE inhibitors and AT1-receptor antagonists in hypertension and related conditions.
Main Results:
- ANG II significantly increases intracellular O2- concentration, playing a key role in hypertension, endothelial dysfunction, and atherosclerosis.
- ROS are integral to signaling pathways regulated by redox-sensitive transcriptional factors like AP-1 and NF-kappaB.
- Clinical benefits of ACE inhibitors as antioxidants are primarily observed in specific risk groups (e.g., diabetes, renal insufficiency), not in essential hypertension.
Conclusions:
- ANG II-induced ROS are critical mediators of vascular and renal pathobiology.
- While drugs targeting ANG II may possess antioxidant properties, their clinical efficacy as such is context-dependent.
- Current evidence does not broadly support the use of ACE inhibitors for antioxidant effects in all hypertensive patients.