Molecular forms of adrenomedullin in pericardial fluid and plasma in patients with ischaemic heart disease.
Experimental studies have demonstrated that adrenomedullin (AM) has a positive inotropic action and exerts inhibitory effects against ventricular remodelling as an autocrine and paracrine factor. However, there is no clinical evidence for AM acting as a local regulator in the human heart. We measured the levels of various molecular forms of AM, i.e. an active form of mature AM (AM-m), an intermediate inactive form of glycine-extended AM (AM-Gly) and total AM (AM-T=AM-m+AM-Gly), in plasma and pericardial fluid using our newly developed immunoradiometric assay in consecutive 67 patients undergoing coronary artery bypass graft surgery. Pericardial fluid and plasma cAMP, atrial natriuretic peptide and brain natriuretic peptide levels were also measured. The relationships between pericardial fluid AM levels and ventricular functions and other hormone levels were analysed. The level of each molecular form of AM in pericardial fluid was closely correlated with that of the other molecular forms of AM in the fluid. However, levels were not correlated with those in plasma. AM-T levels were slightly higher in pericardial fluid than in plasma (+72%; P<0.05), whereas AM-m levels and AM-m/AM-T ratios were markedly higher in pericardial fluid than in plasma (AM-m, +994%; AM-m/AM-T ratio, +443%; both P<0.01). AM-m, AM-Gly and AM-T levels in pericardial fluid were correlated with indices of left ventricular function, and with atrial natriuretic peptide and brain natriuretic peptide levels. Interestingly, AM and cAMP levels were positively correlated in plasma, but negatively correlated in pericardial fluid. In addition, AM-m, AM-Gly and AM-T levels in pericardial fluid were higher in patients with acute coronary syndrome than in those with stable ischaemic heart disease (AM-m, +80%; AM-Gly, +96%; AM-T, +83%; all P<0.01). These results suggest that AM in pericardial fluid reflects cardiac synthesis, and that enhanced cardiac secretion of AM is associated with left ventricular dysfunction, ventricular overload and myocardial ischaemia. Considering that AM has positive inotropic, coronary vasodilatory and anti-remodelling actions, increased cardiac AM may play a compensatory role in the ischaemic and failing myocardium.
Nishikimi
Toshio
T
Department of Hypertension and Cardiorenal Medicine, Dokkyo University School of Medicine, Mibu, Tochigi 321-0293, Japan. nishikim@dokkyomed.ac.jp
Shibasaki
Ikuko
I
Iida
Hiroshi
H
Asakawa
Hiroshi
H
Matsushita
Yasushi
Y
Mori
Hideaki
H
Mochizuki
Yoshihiko
Y
Okamura
Yoshitaka
Y
Horinaka
Shigeo
S
Kangawa
Kenji
K
Shimada
Koichiro
K
Matsuoka
Hiroaki
H
D053607:Adrenomedullin; D000368:Aged; D000369:Aged, 80 and over; D009320:Atrial Natriuretic Factor / Q000032:analysis; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000378:metabolism / Q000503:physiopathology; D000242:Cyclic AMP / Q000032:analysis; D005260:Female; D006801:Humans; D015592:Immunoradiometric Assay / Q000379:methods; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000503:physiopathology; D020097:Natriuretic Peptide, Brain / Q000032:analysis; D010455:Peptides / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D010490:Pericardial Effusion / Q000737:chemistry*; D016277:Ventricular Function, Left
D010455:Peptides; D020097:Natriuretic Peptide, Brain; D053607:Adrenomedullin; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP