Medline ® Abstracts for References 2,3
of 'Actions of angiotensin II on the heart'
Aldosterone production is activated in failing ventricle in humans.
Mizuno Y, Yoshimura M, Yasue H, Sakamoto T, Ogawa H, Kugiyama K, Harada E, Nakayama M, Nakamura S, Ito T, Shimasaki Y, Saito Y, Nakao K
BACKGROUND: Recent reports have indicated that aldosterone is produced in extra-adrenal tissues in animals. The present study was designed to examine whether aldosterone is produced in human heart.
METHODS AND RESULTS: Plasma levels of aldosterone, BNP, and angiotensin-converting enzyme were measured in anterior interventricular vein (AIV), coronary sinus (CS), and aortic root (Ao), respectively, in 20 patients with left ventricular systolic dysfunction (LVSD), 25 patients with LV diastolic dysfunction (LVDD), and 23 control subjects. Aldosterone levels were significantly higher in AIV and CS than Ao in LVSD (98+/-10 versus 72+/-9 pg/mL, P:<0.001, and 97+/-11 versus 72+/-9 pg/mL, P:<0.001, respectively) and LVDD (87+/-10 versus 71+/-9 pg/mL, P:<0.01, and 84+/-10 versus 71+/-9 pg/mL, P:<0.01, respectively) groups, but no differences were observed in levels for these sites in the control group. Levels of ACE activity and BNP also were higher in AIV than Ao in both LV dysfunction groups. The difference in aldosterone levels between AIV and Ao and those in BNP and angiotensin-converting enzyme had a significant positive correlation with LVEDP and a significant negative correlation with LV ejection fraction in the LVSD group.
CONCLUSIONS: Production of aldosterone, angiotensin-converting enzyme, and BNP are activated in failing human ventricle in proportion to severity.
Division of Cardiology, Kumamoto Aging Research Institute, Yamamuro, Kumamoto City 860-8518, Japan.
Activation of cardiac aldosterone production in rat myocardial infarction: effect of angiotensin II receptor blockade and role in cardiac fibrosis.
Silvestre JS, Heymes C, Oubénaïssa A, Robert V, Aupetit-Faisant B, Carayon A, Swynghedauw B, Delcayre C
BACKGROUND: This study analyzed the regulation and the role of the cardiac steroidogenic system in myocardial infarction (MI).
METHODS AND RESULTS: Seven days after MI, rats were randomized to untreated infarcted group or spironolactone- (20 and 80 mg x kg-1 x d-1), losartan- (8 mg x kg-1 x d-1), spironolactone plus losartan-, and L-NAME- (5 mg x kg-1 x d-1) treated infarcted groups for 25 days. Sham-operated rats served as controls. In the noninfarcted myocardium of the left ventricle (LV), MI raised aldosterone synthase mRNA (the terminal enzyme of aldosterone synthesis) by 2. 0-fold and the aldosterone level by 3.7-fold. Conversely, MI decreased 11beta-hydroxylase mRNA (the terminal enzyme of corticosterone synthesis) by 2.4-fold and the corticosterone level by 1.9-fold. MI also induced a 1.9-fold increase in cardiac angiotensin II level. Such cardiac regulations were completely prevented by treatment of the infarcted heart with losartan. The MI-induced collagen deposition in noninfarcted LV myocardium was prevented by 1.6-fold by both low and high doses of spironolactone and by 2.5-fold by losartan. In addition, norepinephrine level was unchanged in infarcted heart but was attenuated by both losartan and spironolactone treatments.
CONCLUSIONS: MI is associated with tissue-specific activation of myocardial aldosterone synthesis. This increase is mediated primarily by cardiac angiotensin II via AT1-subtype receptor and may be involved in post-MI ventricular fibrosis and in control of tissue norepinephrine concentration.
INSERM U127, IFR Circulation, UniversitéD. Diderot, Paris, France.