Rapid actions of aldosterone in vascular health and disease--friend or foe?
The mineralocorticoid receptor (MR) and the enzyme 11betahydroxysteroid dehydrogenase type 2, which confers aldosterone specificity to the MR, are present in endothelium and vascular smooth muscle. In several pathological conditions aldosterone promotes vascular damage by formation of reactive oxygen species. The effect of aldosterone on vascular function, however, is far from clear. By rapid non-genomic mechanisms aldosterone may cause calcium mobilization and vasoconstriction, or may stimulate nitric oxide formation through the PI-3 kinase/Akt pathway and thereby counteract vasoconstriction. Vasoconstrictor, vasodilator or no effects of aldosterone have been reported from studies on human forearm blood flow. Inhibition of MR with spironolactone improves endothelial function in patients with heart failure but worsens endothelial function in type 2 diabetic patients. The aim of the present review is to reconcile some of the apparently conflicting data. A key observation is that reactive oxygen and nitrogen species serve as physiological signaling molecules at low concentrations, while they initiate pathological processes at higher concentrations. The net effect of aldosterone, which stimulates ROS production, therefore depends on the ambient level of oxidative stress. Thus, in situations with low levels of oxidative stress aldosterone may promote vasodilatation, while at higher oxidative stress (high NaCl intake, pre-existing vascular pathological conditions, high oxygen tension in vitro) aldosterone is likely to be associated with vasoconstriction and oxidative damage, and in this setting inhibition of the MR is likely to be beneficial.
Skøtt
Ole
O
Department of Physiology and Pharmacology, University of Southern Denmark, DK-5000 Odense, Denmark. oskott@health.sdu.dk
Uhrenholt
Torben R
TR
Schjerning
Jeppe
J
Hansen
Pernille B L
PB
Rasmussen
Lasse E
LE
Jensen
Boye L
BL
D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000378:metabolism; D000450:Aldosterone / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000502:physiology; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D018161:Receptors, Mineralocorticoid / Q000378:metabolism; D015398:Signal Transduction; D012965:Sodium Chloride / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology
D018161:Receptors, Mineralocorticoid; D012965:Sodium Chloride; D000450:Aldosterone; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2