Title:Are Reactive Oxygen Species Important Mediators of Vascular Dysfunction?
VOLUME: 16 ISSUE: 3
Author(s):Gabriel T. do Vale* and Carlos R. Tirapelli
Affiliation:Escola de Enfermagem de Ribeirao Preto, Laboratory of Pharmacology, Universidade de Sao Paulo (USP), Ribeirão Preto, SP, Escola de Enfermagem de Ribeirao Preto - DEPCH / Faculdade de Ciencias Farmaceuticas de Ribeirao Preto - DFQ, USP, Ribeirao Preto, SP
Keywords:Reactive oxygen species, oxidative stress, hypertension, angiotensin II, antioxidants, oxygen metabolism.
Abstract:Reactive Oxygen Species (ROS) are reactive derivatives of oxygen metabolism. The
ROS generation can be mediated by distinctive enzymatic systems including NADPH oxidases. The
components of this enzyme are expressed in endothelial and vascular smooth muscle cells, adventitial
fibroblasts, and infiltrating monocytes/macrophages. Oxidative stress is a molecular dysregulation
in ROS generation/elimination, which plays a key role in the development of vascular dysfunction
in distinctive conditions including hypertension. It is characterized by vascular inflammation, a
loss of NO bioavailability and endothelial dysfunction. Considering that oxidative stress is a key
mediator of vascular dysfunction, antioxidant therapy with classic antioxidants seemed to be a
promising alternative for the treatment of vascular diseases. In this sense, some commonly used
drugs for the treatment of cardiovascular diseases such as Angiotensin Converting Enzyme (ACE)
inhibitors or angiotensin receptor AT1 antagonists showed antioxidant effects that might have contributed,
at least in part, to the beneficial effects of these drugs on the treatment of cardiovascular
diseases. The effectiveness of these drugs shows that ROS are in fact important mediators of vascular
dysfunction and that angiotensin II plays a critical role in such response.
